Charlie Norwood VA Medical Center

The mechanism of mitochondrial damage, a key contributor to renal tubular cell death during acute kidney injury, remains largely unknown. Here, we have demonstrated a striking morphological change of mitochondria in experimental models of renal ischemia/reperfusion and cisplatin-induced nephrotoxicity. This change contributed to mitochondrial outer membrane permeabilization, release of apoptogenic factors, and consequent apoptosis. Following either ATP depletion or cisplatin treatment of rat renal tubular cells, mitochondrial fragmentation was observed prior to cytochrome c release and apoptosis. This mitochondrial fragmentation was inhibited by Bcl2 but not by caspase inhibitors. Dynamin-related protein 1 (Drp1), a critical mitochondrial fission protein, translocated to mitochondria early during tubular cell injury, and both siRNA knockdown of Drp1 and expression of a dominant-negative Drp1 attenuated mitochondrial fragmentation, cytochrome c release, caspase activation, and apoptosis. Further in vivo analysis revealed that mitochondrial fragmentation also occurred in proximal tubular cells in mice during renal ischemia/reperfusion and cisplatin-induced nephrotoxicity. Notably, both tubular cell apoptosis and acute kidney injury were attenuated by mdivi-1, a newly identified pharmacological inhibitor of Drp1. This study demonstrates a rapid regulation of mitochondrial dynamics during acute kidney injury and identifies mitochondrial fragmentation as what we believe to be a novel mechanism contributing to mitochondrial damage and apoptosis in vivo in mouse models of disease.

AKI is pathologically characterized by sublethal and lethal damage of renal tubules. Under these conditions, renal tubular cell death may occur by regulated necrosis (RN) or apoptosis. In the last two decades, tubular apoptosis has been shown in preclinical models and some clinical samples from patients with AKI. Mechanistically, apoptotic cell death in AKI may result from well described extrinsic and intrinsic pathways as well as ER stress. Central converging nodes of these pathways are mitochondria, which become fragmented and sensitized to membrane permeabilization in response to cellular stress, resulting in the release of cell death-inducing factors. Whereas apoptosis is known to be regulated, tubular necrosis was thought to occur by accident until recent work unveiled several RN subroutines, most prominently receptor-interacting protein kinase-dependent necroptosis and RN induced by mitochondrial permeability transition. Additionally, other cell death pathways, like pyroptosis and ferroptosis, may also be of pathophysiologic relevance in AKI. Combination therapy targeting multiple cell-death pathways may, therefore, provide maximal therapeutic benefits.

Myosin Va is associated with discrete vesicle populations in a number of cell types, but little is known of the function of myosin Vb. Yeast two-hybrid screening of a rabbit parietal cell cDNA library with dominant active Rab11a (Rab11aS20V) identified myosin Vb as an interacting protein for Rab11a, a marker for plasma membrane recycling systems. The isolated clone, corresponding to the carboxyl terminal 60 kDa of the myosin Vb tail, interacted with all members of the Rab11 family (Rab11a, Rab11b, and Rab25). GFP-myosin Vb and endogenous myosin Vb immunoreactivity codistributed with Rab11a in HeLa and Madin-Darby canine kidney (MDCK) cells. As with Rab11a in MDCK cells, the myosin Vb immunoreactivity was dispersed with nocodazole treatment and relocated to the apical corners of cells with taxol treatment. A green fluorescent protein (GFP)-myosin Vb tail chimera overexpressed in HeLa cells retarded transferrin recycling and caused accumulation of transferrin and the transferrin receptor in pericentrosomal vesicles. Expression of the myosin Vb tail chimera in polarized MDCK cells stably expressing the polymeric IgA receptor caused accumulation of basolaterally endocytosed polymeric IgA and the polymeric IgA receptor in the pericentrosomal region. The myosin Vb tail had no effects on transferrin trafficking in polarized MDCK cells. The GFP-myosin Va tail did not colocalize with Rab11a and had no effects on recycling system vesicle distribution in either HeLa or MDCK cells. The results indicate myosin Vb is associated with the plasma membrane recycling system in nonpolarized cells and the apical recycling system in polarized cells. The dominant negative effects of the myosin Vb tail chimera indicate that this unconventional myosin is required for transit out of plasma membrane recycling systems.

Oxidative stress is a common denominator in the pathology of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis, as well as in ischemic and traumatic brain injury. The brain is highly vulnerable to oxidative damage due to its high metabolic demand. However, therapies attempting to scavenge free radicals have shown little success. By shifting the focus to inhibit the generation of damaging free radicals, recent studies have identified NADPH oxidase as a major contributor to disease pathology. NADPH oxidase has the primary function to generate free radicals. In particular, there is growing evidence that the isoforms NOX1, NOX2, and NOX4 can be upregulated by a variety of neurodegenerative factors. The majority of recent studies have shown that genetic and pharmacological inhibition of NADPH oxidase enzymes are neuroprotective and able to reduce detrimental aspects of pathology following ischemic and traumatic brain injury, as well as in chronic neurodegenerative disorders. This review aims to summarize evidence supporting the role of NADPH oxidase in the pathology of these neurological disorders, explores pharmacological strategies of targeting this major oxidative stress pathway, and outlines obstacles that need to be overcome for successful translation of these therapies to the clinic.

Despite breakthroughs in immune checkpoint inhibitor (ICI) immunotherapy, not all human cancers respond to ICI immunotherapy and a large fraction of patients with the responsive types of cancers do not respond to current ICI immunotherapy. This clinical conundrum suggests that additional immune checkpoints exist. We report here that interferon regulatory factor 8 (IRF8) deficiency led to impairment of cytotoxic T lymphocyte (CTL) activation and allograft tumor tolerance. However, analysis of chimera mice with competitive reconstitution of WT and IRF8-KO bone marrow cells as well as mice with IRF8 deficiency only in T cells indicated that IRF8 plays no intrinsic role in CTL activation. Instead, IRF8 functioned as a repressor of osteopontin (OPN), the physiological ligand for CD44 on T cells, in CD11b+Ly6CloLy6G+ myeloid cells and OPN acted as a potent T cell suppressor. IRF8 bound to the Spp1 promoter to repress OPN expression in colon epithelial cells, and colon carcinoma exhibited decreased IRF8 and increased OPN expression. The elevated expression of OPN in human colon carcinoma was correlated with decreased patient survival. Our data indicate that myeloid and tumor cell-expressed OPN acts as an immune checkpoint to suppress T cell activation and confer host tumor immune tolerance.

BACKGROUND: In obesity, the excessive synthesis of aldosterone contributes to the development and progression of metabolic and cardiovascular dysfunctions. Obesity-induced hyperaldosteronism is independent of the known regulators of aldosterone secretion, but reliant on unidentified adipocyte-derived factors. We hypothesized that the adipokine leptin is a direct regulator of aldosterone synthase (CYP11B2) expression and aldosterone release and promotes cardiovascular dysfunction via aldosterone-dependent mechanisms. METHODS AND RESULTS: Immunostaining of human adrenal cross-sections and adrenocortical cells revealed that adrenocortical cells coexpress CYP11B2 and leptin receptors. Measurements of adrenal CYP11B2 expression and plasma aldosterone levels showed that increases in endogenous (obesity) or exogenous (infusion) leptin dose-dependently raised CYP11B2 expression and aldosterone without elevating plasma angiotensin II, potassium or corticosterone. Neither angiotensin II receptors blockade nor α and β adrenergic receptors inhibition blunted leptin-induced aldosterone secretion. Identical results were obtained in cultured adrenocortical cells. Enhanced leptin signaling elevated CYP11B2 expression and plasma aldosterone, whereas deficiency in leptin or leptin receptors blunted obesity-induced increases in CYP11B2 and aldosterone, ruling out a role for obesity per se. Leptin increased intracellular calcium, elevated calmodulin and calmodulin-kinase II expression, whereas calcium chelation blunted leptin-mediated increases in CYP11B2, in adrenocortical cells. Mineralocorticoid receptor blockade blunted leptin-induced endothelial dysfunction and increases in cardiac fibrotic markers. CONCLUSIONS: Leptin is a newly described regulator of aldosterone synthesis that acts directly on adrenal glomerulosa cells to increase CYP11B2 expression and enhance aldosterone production via calcium-dependent mechanisms. Furthermore, leptin-mediated aldosterone secretion contributes to cardiovascular disease by promoting endothelial dysfunction and the expression of profibrotic markers in the heart.

Exosomes, which are nanosized vesicles secreted by cells, are attracting increasing interest in the field of biomedical research due to their unique properties, including biocompatibility, cargo loading capacity, and deep tissue penetration. They serve as natural signaling agents in intercellular communication, and their inherent ability to carry proteins, lipids, and nucleic acids endows them with remarkable therapeutic potential. Thus, exosomes can be exploited for diverse therapeutic applications, including chemotherapy, gene therapy, and photothermal therapy. Moreover, their capacity for homotypic targeting and self-recognition provides opportunities for personalized medicine. Despite their advantages as novel therapeutic agents, there are several challenges in optimizing cargo loading efficiency and structural stability and in defining exosome origins. Future research should include the development of large-scale, quality-controllable production methods, the refinement of drug loading strategies, and extensive in vivo studies and clinical trials. Despite the unresolved difficulties, the use of exosomes as efficient, stable, and safe therapeutic delivery systems is an interesting area in biomedical research. Therefore, this review describes exosomes and summarizes cutting-edge studies published in high-impact journals that have introduced novel or enhanced therapeutic effects using exosomes as a drug delivery system in the past 2 years. We provide an informative overview of the current state of exosome research, highlighting the unique properties and therapeutic applications of exosomes. We also emphasize challenges and future directions, underscoring the importance of addressing key issues in the field. With this review, we encourage researchers to further develop exosome-based drugs for clinical application, as such drugs may be among the most promising next-generation therapeutics.

For many years, modulators of the renin angiotensin system (RAS) have been trusted by clinicians for the control of essential hypertension. It was recently demonstrated that these modulators have other pleiotropic properties independent of their hypotensive effects, such as enhancement of cognition. Within the brain, different components of the RAS have been extensively studied in the context of neuroprotection and cognition. Interestingly, a crosstalk between the RAS and other systems such as cholinergic, dopaminergic and adrenergic systems have been demonstrated. In this review, the preclinical and clinical evidence for the impact of RAS modulators on cognitive impairment of multiple etiologies will be discussed. In addition, the expression and function of different receptor subtypes within the RAS such as: Angiotensin II type I receptor (AT1R), Angiotensin II type II receptor (AT2R), Angiotensin IV receptor (AT4R), Mas receptor (MasR), and Mas-related-G protein-coupled receptor (MrgD), on different cell types within the brain will be presented. We aim to direct the attention of the scientific community to the plethora of evidence on the importance of the RAS on cognition and to the different disease conditions in which these agents can be beneficial.

Cisplatin is one of the most effective anti-cancer drugs; however, the use of cisplatin is limited by its toxicity in normal tissues, particularly injury of the kidneys. The mechanisms underlying the therapeutic effects of cisplatin in cancers and side effects in normal tissues are largely unclear. Recent work has suggested a role for p53 in cisplatin-induced renal cell apoptosis and kidney injury; however, the signaling pathway leading to p53 activation and renal apoptosis is unknown. Here we demonstrate an early DNA damage response during cisplatin treatment of renal cells and tissues. Importantly, in the DNA damage response, we demonstrate a critical role for ATR, but not ATM (ataxia telangiectasia mutated) or DNA-PK (DNA-dependent protein kinase), in cisplatin-induced p53 activation and apoptosis. We show that ATR is specifically activated during cisplatin treatment and co-localizes with H2AX, forming nuclear foci at the site of DNA damage. Blockade of ATR with a dominant-negative mutant inhibits cisplatin-induced p53 activation and renal cell apoptosis. Consistently, cisplatin-induced p53 activation and apoptosis are suppressed in ATR-deficient fibroblasts. Downstream of ATR, both Chk1 and Chk2 are phosphorylated during cisplatin treatment in an ATR-dependent manner. Interestingly, following phosphorylation, Chk1 is degraded via the proteosomal pathway, whereas Chk2 is activated. Inhibition of Chk2 by a dominant-negative mutant or gene deficiency attenuates cisplatin-induced p53 activation and apoptosis. In vivo in C57BL/6 mice, ATR and Chk2 are activated in renal tissues following cisplatin treatment. Together, the results suggest an important role for the DNA damage response mediated by ATR-Chk2 in p53 activation and renal cell apoptosis during cisplatin nephrotoxicity. Cisplatin is one of the most effective anti-cancer drugs; however, the use of cisplatin is limited by its toxicity in normal tissues, particularly injury of the kidneys. The mechanisms underlying the therapeutic effects of cisplatin in cancers and side effects in normal tissues are largely unclear. Recent work has suggested a role for p53 in cisplatin-induced renal cell apoptosis and kidney injury; however, the signaling pathway leading to p53 activation and renal apoptosis is unknown. Here we demonstrate an early DNA damage response during cisplatin treatment of renal cells and tissues. Importantly, in the DNA damage response, we demonstrate a critical role for ATR, but not ATM (ataxia telangiectasia mutated) or DNA-PK (DNA-dependent protein kinase), in cisplatin-induced p53 activation and apoptosis. We show that ATR is specifically activated during cisplatin treatment and co-localizes with H2AX, forming nuclear foci at the site of DNA damage. Blockade of ATR with a dominant-negative mutant inhibits cisplatin-induced p53 activation and renal cell apoptosis. Consistently, cisplatin-induced p53 activation and apoptosis are suppressed in ATR-deficient fibroblasts. Downstream of ATR, both Chk1 and Chk2 are phosphorylated during cisplatin treatment in an ATR-dependent manner. Interestingly, following phosphorylation, Chk1 is degraded via the proteosomal pathway, whereas Chk2 is activated. Inhibition of Chk2 by a dominant-negative mutant or gene deficiency attenuates cisplatin-induced p53 activation and apoptosis. In vivo in C57BL/6 mice, ATR and Chk2 are activated in renal tissues following cisplatin treatment. Together, the results suggest an important role for the DNA damage response mediated by ATR-Chk2 in p53 activation and renal cell apoptosis during cisplatin nephrotoxicity. Cisplatin is a highly effective antineoplastic agent that has been widely used for cancer therapy (1Siddik Z.H. Oncogene. 2003; 22: 7265-7279Crossref PubMed Scopus (2672) Google Scholar, 2Wang D. Lippard S.J. Nat. Rev. Drug Discov. 2005; 4: 307-320Crossref PubMed Scopus (3056) Google Scholar). However, the therapeutic efficacy of cisplatin is limited by its toxicity to normal tissues, notably the kidneys (3Arany I. Safirstein R.L. Semin. Nephrol. 2003; 23: 460-464Abstract Full Text Full Text PDF PubMed Scopus (825) Google Scholar, 4Parant J. Chavez-Reyes A. Little N.A. Yan W. Reinke V. Jochemsen A.G. Lozano G. Nat. Genet. 2001; 29: 92-95Crossref PubMed Scopus (416) Google Scholar). In the kidneys, cisplatin induces cell injury and death in renal tubular cells, leading to acute renal failure (3Arany I. Safirstein R.L. Semin. Nephrol. 2003; 23: 460-464Abstract Full Text Full Text PDF PubMed Scopus (825) Google Scholar, 4Parant J. Chavez-Reyes A. Little N.A. Yan W. Reinke V. Jochemsen A.G. Lozano G. Nat. Genet. 2001; 29: 92-95Crossref PubMed Scopus (416) Google Scholar). Indeed, about a quarter of acute renal failure cases are attributable to cisplatin nephrotoxicity (5Berns J.S. Ford P.A. Semin. Nephrol. 1997; 17: 54-66PubMed Google Scholar). Multiple signaling pathways are activated by cisplatin in renal tubular cells (6Ramesh G. Reeves W.B. Kidney Int. Suppl. 2004; 91: 56-61Abstract Full Text Full Text PDF PubMed Scopus (155) Google Scholar, 7Arany I. Megyesi J.K. Kaneto H. Price P.M. Safirstein R.L. Am. J. Physiol. 2004; 287: F543-F549Crossref PubMed Scopus (200) Google Scholar, 8Price P.M. Megyesi J. Safirstein R.L. Semin. Nephrol. 2003; 23: 449-459Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar, 9Baliga R. Ueda N. Walker P.D. Shah S.V. Drug Metab. Rev. 1999; 31: 971-997Crossref PubMed Scopus (312) Google Scholar, 10Cummings B.S. Schnellmann R.G. J. Pharmacol. Exp. Ther. 2002; 302: 8-17Crossref PubMed Scopus (313) Google Scholar, 11Zhuang S. Schnellmann R.G. J. Pharmacol. Exp. Ther. 2006; 319: 991-997Crossref PubMed Scopus (324) Google Scholar, 12Nowak G. J. Biol. Chem. 2002; 277: 43377-43388Abstract Full Text Full Text PDF PubMed Scopus (235) Google Scholar, 13Li S. Basnakian A. Bhatt R. Megyesi J. Gokden N. Shah S.V. Portilla D. Am. J. Physiol. 2004; 287: F990-F998Crossref PubMed Scopus (87) Google Scholar, 14Agarwal A. Balla J. Alam J. Croatt A.J. Nath K.A. Kidney Int. 1995; 48: 1298-1307Abstract Full Text PDF PubMed Scopus (235) Google Scholar); nevertheless, the mechanism of renal cell death during cisplatin nephrotoxicity remains largely unclear. As a result, effective interventions for renoprotection during cisplatin chemotherapy are currently lacking. Recent work has suggested a role for p53 signaling in renal cell apoptosis and cisplatin nephrotoxicity (10Cummings B.S. Schnellmann R.G. J. Pharmacol. Exp. Ther. 2002; 302: 8-17Crossref PubMed Scopus (313) Google Scholar, 15Jiang M. Yi X. Hsu S. Wang C.Y. Dong Z. Am. J. Physiol. 2004; 287: F1140-F1147Crossref PubMed Scopus (148) Google Scholar, 16Seth R. Yang C. Kaushal V. Shah S.V. Kaushal G.P. J. Biol. Chem. 2005; 280: 31230-31239Abstract Full Text Full Text PDF PubMed Scopus (156) Google Scholar, 17Wei Q. Dong G. Yang Megyesi J. Price P.M. Dong Z. Am. J. Physiol. PubMed Scopus Google Scholar). p53 is activated early during cisplatin treatment and induces the of M. Yi X. Hsu S. Wang C.Y. Dong Z. Am. J. Physiol. 2004; 287: F1140-F1147Crossref PubMed Scopus (148) Google Scholar, M. Q. Wang J. Q. J. Dong Z. Oncogene. 2006; PubMed Scopus Google Scholar). of p53 cisplatin-induced renal cell apoptosis in and nephrotoxicity in vivo M. Yi X. Hsu S. Wang C.Y. Dong Z. Am. J. Physiol. 2004; 287: F1140-F1147Crossref PubMed Scopus (148) Google Scholar, 17Wei Q. Dong G. Yang Megyesi J. Price P.M. Dong Z. Am. J. Physiol. PubMed Scopus Google Scholar). the signaling that to p53 activation remains mechanism of p53 activation during cisplatin nephrotoxicity is DNA damage (1Siddik Z.H. Oncogene. 2003; 22: 7265-7279Crossref PubMed Scopus (2672) Google Scholar, 2Wang D. Lippard S.J. Nat. Rev. Drug Discov. 2005; 4: 307-320Crossref PubMed Scopus (3056) Google Scholar). is that cisplatin with the in the in or D. Lippard S.J. Nat. Rev. Drug Discov. 2005; 4: 307-320Crossref PubMed Scopus (3056) Google Scholar, Lippard S.J. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar, P.M. Lippard S.J. 1995; PubMed Scopus Google Scholar). by cisplatin DNA and gene and in D. Lippard S.J. Nat. Rev. Drug Discov. 2005; 4: 307-320Crossref PubMed Scopus (3056) Google Scholar, Lippard S.J. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar). The the activation of a signaling to p53 and The of DNA damage ATM (ataxia telangiectasia ATR (ataxia telangiectasia and and DNA-PK (DNA-dependent protein J. 2003; PubMed Scopus Google Scholar, 2006; Full Text Full Text PDF PubMed Scopus Google Scholar). In response to DNA damage or protein are to the site of DNA forming nuclear 2006; Full Text Full Text PDF PubMed Scopus Google Scholar, 2001; PubMed Scopus Google Scholar, A. S. Rev. 2004; PubMed Scopus Google Scholar). is by and activation of signaling Chk1 and cell or apoptosis 2006; Full Text Full Text PDF PubMed Scopus Google Scholar, Oncogene. 2004; 23: PubMed Scopus Google Scholar). Importantly, protein and p53 2006; Full Text Full Text PDF PubMed Scopus Google Scholar, Oncogene. 2004; 23: PubMed Scopus Google Scholar). the of DNA damage response, is not the DNA by cisplatin is and to p53 activation and cell death (1Siddik Z.H. Oncogene. 2003; 22: 7265-7279Crossref PubMed Scopus (2672) Google Scholar, 2Wang D. Lippard S.J. Nat. Rev. Drug Discov. 2005; 4: 307-320Crossref PubMed Scopus (3056) Google Scholar). In the of cisplatin a DNA damage response is and is in p53 activation and renal cell apoptosis are J. Chavez-Reyes A. Little N.A. Yan W. Reinke V. Jochemsen A.G. Lozano G. Nat. Genet. 2001; 29: 92-95Crossref PubMed Scopus (416) Google Scholar). of the signaling activated by cisplatin in cell of cisplatin toxicity in normal tissues. In the we show that ATR, but not ATM or is activated during cisplatin treatment of renal cells and tissues. ATR Chk2 to p53 activation and apoptosis. results suggest an important role for the ATR-Chk2 signaling in p53 activation and renal cell apoptosis during cisplatin nephrotoxicity. The kidney tubular cell used kidney tubular and M. Yi X. Hsu S. Wang C.Y. Dong Z. Am. J. Physiol. 2004; 287: F1140-F1147Crossref PubMed Scopus (148) Google Scholar, W. Kidney Int. Full Text PDF PubMed Scopus Google Scholar). kidney cells in with and and ATR-deficient the and in with and and cells in C. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar, J. Wang C. J. C. S.J. Wang W. J. Biol. Chem. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar). kidney tubular cell kidney protein phosphorylated p53 ATR the following and and at the of p53 and for Cisplatin treatment of cells M. Yi X. Hsu S. Wang C.Y. Dong Z. Am. J. Physiol. 2004; 287: F1140-F1147Crossref PubMed Scopus (148) Google Scholar, M. Q. Wang J. Q. J. Dong Z. Oncogene. 2006; PubMed Scopus Google Scholar, M. N. Yang Dong Z. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). Cisplatin used at for cells, for cells, for normal and ATR-deficient and for cisplatin cells or to cell for in vivo C57BL/6 of with a of cisplatin to kidney injury M. Q. N. Dong G. Wang C.Y. Yang Dong Z. Pharmacol. PubMed Scopus Google Scholar, Q. Dong G. J. Dong Z. Kidney Int. Full Text Full Text PDF PubMed Scopus Google Scholar, Q. Wang Dong Z. Am. J. Nephrol. 2005; PubMed Scopus (87) Google Scholar). work in with the use by the and of the of and at ATR, and Chk2 site J. Wang C. J. C. S.J. Wang W. J. Biol. Chem. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar, S. A. PubMed Scopus Google Scholar, H. H. Biol. 2001; PubMed Scopus Google Scholar, Google Scholar). and cells cells the cells, protein with the gene at a of The the cells a used for and cell to the effects of As a used for tissues and cells with the in the of and J. N. Wang C.Y. Wang W. Dong Z. Am. J. Physiol. 2006; PubMed Scopus Google Scholar). The to for ATR, or The to a protein and p53 the a at to the The to and to the of p53 to the protein of protein the cells and tissues. with the in the of and and to J. N. Wang C.Y. Wang W. Dong Z. Am. J. Physiol. 2006; PubMed Scopus Google Scholar, J. Q. Wang C.Y. Dong Z. J. Biol. Chem. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar). The in for by in cell by the of protein in for The The in a and to the at by the the the cells cisplatin the cells with and with in and normal in The cells with and by with a of and by and or cells with for and used to the and nuclear apoptosis nuclear and and of with in to the of used a of apoptosis M. N. Yang Dong Z. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). by to an with a of of at at of the in the a M. N. Yang Dong Z. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). cells by and by at for The cells in at a of The cell of with of and of for at the with of and with a of and by at the M. Q. Wang J. Q. J. Dong Z. Oncogene. 2006; PubMed Scopus Google Scholar, J. Q. Wang C.Y. Dong Z. J. Biol. Chem. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar). the cells with in an and for at The a and used for of by the The by to of ATR, but ATM or during Cisplatin of work has an in of cisplatin nephrotoxicity cells M. Yi X. Hsu S. Wang C.Y. Dong Z. Am. J. Physiol. 2004; 287: F1140-F1147Crossref PubMed Scopus (148) Google Scholar). In cisplatin induces apoptosis in p53 is activated early following cisplatin and its the DNA protein we cell of cisplatin treatment and and The to an in p53 by p53 in the As in the of ATM phosphorylated p53 of cisplatin treatment and at DNA-PK in cells with work J. N. Wang C.Y. Wang W. Dong Z. Am. J. Physiol. 2006; PubMed Scopus Google protein of ATM and DNA-PK not during of cisplatin and The results suggest that the of ATM and DNA-PK during cisplatin treatment to of protein In we a of ATR during cisplatin treatment whereas ATR by of the is in ATM and DNA-PK are whereas ATR is activated during cisplatin treatment of cells the activation of we cells with cisplatin or and ATM at 2003; PubMed Scopus Google Scholar). As in cisplatin not ATM phosphorylation, whereas in the ATR activation during cisplatin we the of the protein has been in ATR activation during 2001; PubMed Scopus Google Scholar, A. S. Rev. 2004; PubMed Scopus Google Scholar). ATR and The for the of As in cisplatin treatment of ATR with In and in protein In ATM not with during cisplatin treatment Together, the results suggest a activation of ATR during cisplatin treatment of renal tubular of ATR to during Cisplatin critical of ATR activation during is the of ATR to nuclear signaling and in response to DNA damage 2001; PubMed Scopus Google Scholar, A. S. Rev. 2004; PubMed Scopus Google Scholar). the of ATR we In cells, ATR a in the cisplatin ATR and the of nuclear foci Cisplatin Importantly, at the nuclear ATR with phosphorylated a DNA damage response protein and of The of ATR and phosphorylated to nuclear foci at of cisplatin treatment and we that phosphorylated during cisplatin treatment in a in ATR-deficient cells but not in cells that ATR is the protein for at the nuclear foci during cisplatin treatment. Together, results for an early DNA damage response and ATR activation during cisplatin nephrotoxicity. of ATR in p53 during Cisplatin induces an early p53 activation in renal tubular cells, leading to gene and apoptosis M. Yi X. Hsu S. Wang C.Y. Dong Z. Am. J. Physiol. 2004; 287: F1140-F1147Crossref PubMed Scopus (148) Google Scholar, 16Seth R. Yang C. Kaushal V. Shah S.V. Kaushal G.P. J. Biol. Chem. 2005; 280: 31230-31239Abstract Full Text Full Text PDF PubMed Scopus (156) Google Scholar, M. Q. Wang J. Q. J. Dong Z. Oncogene. 2006; PubMed Scopus Google Scholar). results the activation of ATR, but not ATM or during cisplatin treatment of we that the DNA damage response mediated by ATR to cisplatin-induced p53 activation in renal tubular we the effects of dominant-negative ATR p53 cells with or a to the cells for cisplatin by to p53 In cells, the of cisplatin the cells that with Cisplatin whereas the cells with dominant-negative ATR not Cisplatin p53 activation not suppressed in cells in the The in cells not for of the effects of we the effects of ATR in cells, a of cells with or and with As in cisplatin p53 activation or in cells but not in the cells that with a role for ATR in p53 activation during cisplatin treatment. we cisplatin-induced p53 activation in and fibroblasts. cisplatin-induced p53 in ATR-deficient cells In p53 not but in cells results suggest that ATR has a critical role in p53 activation during cisplatin treatment. Blockade of ATR tubular cell apoptosis during cisplatin nephrotoxicity is by signaling pathways (6Ramesh G. Reeves W.B. Kidney Int. Suppl. 2004; 91: 56-61Abstract Full Text Full Text PDF PubMed Scopus (155) Google Scholar, 7Arany I. Megyesi J.K. Kaneto H. Price P.M. Safirstein R.L. Am. J. Physiol. 2004; 287: F543-F549Crossref PubMed Scopus (200) Google Scholar, 8Price P.M. Megyesi J. Safirstein R.L. Semin. Nephrol. 2003; 23: 449-459Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar, 9Baliga R. Ueda N. Walker P.D. Shah S.V. Drug Metab. Rev. 1999; 31: 971-997Crossref PubMed Scopus (312) Google Scholar, 10Cummings B.S. Schnellmann R.G. J. Pharmacol. Exp. Ther. 2002; 302: 8-17Crossref PubMed Scopus (313) Google Scholar, 11Zhuang S. Schnellmann R.G. J. Pharmacol. Exp. Ther. 2006; 319: 991-997Crossref PubMed Scopus (324) Google Scholar, 12Nowak G. J. Biol. Chem. 2002; 277: 43377-43388Abstract Full Text Full Text PDF PubMed Scopus (235) Google Scholar, 13Li S. Basnakian A. Bhatt R. Megyesi J. Gokden N. Shah S.V. Portilla D. Am. J. Physiol. 2004; 287: F990-F998Crossref PubMed Scopus (87) Google Scholar, 14Agarwal A. Balla J. Alam J. Croatt A.J. Nath K.A. Kidney Int. 1995; 48: 1298-1307Abstract Full Text PDF PubMed Scopus (235) Google and p53 activation (10Cummings B.S. Schnellmann R.G. J. Pharmacol. Exp. Ther. 2002; 302: 8-17Crossref PubMed Scopus (313) Google Scholar, 15Jiang M. Yi X. Hsu S. Wang C.Y. Dong Z. Am. J. Physiol. 2004; 287: F1140-F1147Crossref PubMed Scopus (148) Google Scholar, 16Seth R. Yang C. Kaushal V. Shah S.V. Kaushal G.P. J. Biol. Chem. 2005; 280: 31230-31239Abstract Full Text Full Text PDF PubMed Scopus (156) Google Scholar, 17Wei Q. Dong G. Yang Megyesi J. Price P.M. Dong Z. Am. J. Physiol. PubMed Scopus Google Scholar). we a role for ATR in p53 activation during cisplatin treatment we that of ATR cisplatin-induced tubular cell apoptosis. we cells with dominant-negative ATR or a by and nuclear As in cisplatin apoptosis in of cells in the or but in of the cells with Consistently, ATR-deficient to cisplatin-induced apoptosis cells ATR deficiency cisplatin-induced activation in cells We the effects of dominant-negative ATR cisplatin-induced apoptosis in cells by following As in cells cells that for cisplatin cells in the that with In apoptosis suppressed to in the with dominant-negative ATR ATR p53 and to cisplatin-induced apoptosis. Chk2 and Chk1 during Cisplatin and of one of the most protein activated during ATR a of protein leading to the activation of a signaling J. 2003; PubMed Scopus Google Scholar, K.A. DNA PubMed Scopus Google Scholar). Chk1 and Chk2 are the protein that are activated of ATM and ATR J. 2003; PubMed Scopus Google Scholar, A. S. Rev. 2004; PubMed Scopus Google Scholar). Chk1 and we in cells following cisplatin treatment. As in Chk1 phosphorylated at of cisplatin treatment. Interestingly, early Chk1 by of As a result, both and phosphorylated Chk1 of cisplatin Cisplatin Chk2 however, Chk2 not degraded during cisplatin treatment that by to of Chk1 via the pathway W. 2005; Full Text Full Text PDF PubMed Scopus (235) Google Scholar). Consistently, we that a proteosomal cisplatin-induced Chk1 We the role of ATR in Chk1 and Chk2 a mutant of In cells with cisplatin Chk1 at and at both Chk1 and in cells with ATR Cisplatin Chk2 at by the of dominant-negative ATR Together, results demonstrate an early activation of Chk1 and Chk2 during cisplatin treatment of renal Importantly, ATR to a critical of Chk1 and Chk2 the of Chk2 in p53 during Cisplatin both Chk1 and Chk2 phosphorylated early during cisplatin Chk1 degraded whereas Chk2 a or activation We Chk2 for its in p53 and cisplatin-induced apoptosis. We Chk2 activation during cisplatin treatment by the in that Chk2 activated following cisplatin the effects of dominant-negative Chk2 cisplatin-induced p53 activation in cells with or to the cells for p53 or activation by As in p53 activation during cisplatin treatment in cells that with Consistently, cisplatin-induced p53 in cells, by In Chk1 not p53 We that cisplatin-induced p53 in cells the results of a role for Chk2 in p53 during cisplatin treatment. of Chk2 Inhibition to the role of Chk2 signaling in cisplatin-induced apoptosis. cells with and dominant-negative Chk2 or and to of cisplatin in cells by and nuclear As in cisplatin apoptosis in or cells but in the cells with Interestingly, apoptosis during cisplatin treatment by the of with for a role of Chk2 in cisplatin the cells apoptosis and activation and In we the effects of dominant-negative Chk2 cisplatin-induced apoptosis in cells by following As in cisplatin suppressed to by Chk2 an important role in cisplatin-induced apoptosis. of Chk2 by ATR, is suggested that the ATR-Chk2 signaling to p53 activation and tubular cell apoptosis during cisplatin nephrotoxicity. ATR and Chk2 in and during Cisplatin work that a is by cisplatin in a M. Q. Wang J. Q. J. Dong Z. Oncogene. 2006; PubMed Scopus Google Scholar). in to leading to activation and apoptosis M. Q. Wang J. Q. J. Dong Z. Oncogene. 2006; PubMed Scopus Google Scholar). to the that are by we and activation during cisplatin treatment. we the effects of dominant-negative ATR and Chk2 in As in by cisplatin in cells, and the by both and Consistently, and and activation during cisplatin treatment p53 the of and 1995; Full Text PDF PubMed Scopus Google Scholar, R. H. J. N. PubMed Scopus Google Scholar). However, not show an of during cisplatin treatment in results suggest by ATR-Chk2 and pathway of apoptosis. of ATR and Chk2 during Cisplatin in cisplatin induces and a DNA damage response in vivo in the kidneys is unknown. we used a of cisplatin nephrotoxicity M. Q. N. Dong G. Wang C.Y. Yang Dong Z. Pharmacol. PubMed Scopus Google Scholar, Q. Dong G. J. Dong Z. Kidney Int. Full Text Full Text PDF PubMed Scopus Google Scholar, Q. Wang Dong Z. Am. J. Nephrol. 2005; PubMed Scopus (87) Google Scholar). In of cisplatin C57BL/6 to acute kidney injury in by and tubular apoptosis M. Q. N. Dong G. Wang C.Y. Yang Dong Z. Pharmacol. PubMed Scopus Google Scholar, Q. Dong G. J. Dong Z. Kidney Int. Full Text Full Text PDF PubMed Scopus Google Scholar, Q. Wang Dong Z. Am. J. Nephrol. 2005; PubMed Scopus (87) Google Scholar). tissues of cisplatin treatment for in DNA damage As in ATM of cisplatin whereas ATM at ATR not a in Chk1 at of cisplatin but both and at and The most or activation in and cisplatin kidney tissues of not the in vivo activation of we ATR, or Chk2 for an in The to an in p53 the by p53 As in ATM by of cisplatin of protein during cisplatin nephrotoxicity. In the of both ATR and Chk2 and of cisplatin treatment and results that a DNA damage response mediated by ATR-Chk2 is activated in vivo during cisplatin nephrotoxicity. has the for an early DNA damage response mediated by ATR and Chk2 during cisplatin nephrotoxicity. Importantly, has a role for signaling in p53 activation and apoptosis. a signaling is DNA damage or by cisplatin to a activation of ATR and of ATM and ATR Chk1 and Chk2 and phosphorylation, Chk1 is but Chk2 is activated to and p53 induces the of in to for leading to by activation and apoptosis As of the results been in and and cells, is suggested that cisplatin signaling in cell renal tubular cell apoptosis during cisplatin nephrotoxicity pathways (3Arany I. Safirstein R.L. Semin. Nephrol. 2003; 23: 460-464Abstract Full Text Full Text PDF PubMed Scopus (825) Google Scholar, 4Parant J. Chavez-Reyes A. Little N.A. Yan W. Reinke V. Jochemsen A.G. Lozano G. Nat. Genet. 2001; 29: 92-95Crossref PubMed Scopus (416) Google Scholar). The pathway is a signaling pathway for DNA damage response the is not of The DNA damage response is a highly and signaling A. S. Rev. 2004; PubMed Scopus Google Scholar). that ATR, and DNA-PK that and the damage and Chk1 and that cell DNA and apoptosis J. 2003; PubMed Scopus Google Scholar, 2006; Full Text Full Text PDF PubMed Scopus Google Scholar, A. S. Rev. 2004; PubMed Scopus Google Scholar). The signaling activated is the and of DNA damage and the cell In we show ATM and DNA-PK are not activated but during cisplatin treatment work that ATM a role during cisplatin treatment J. N. Wang C.Y. Wang W. Dong Z. Am. J. Physiol. 2006; PubMed Scopus Google Scholar). Consistently, Wang Wang G. J. Biol. Chem. 2006; Full Text Full Text PDF PubMed Scopus Google that in ATM is activated during cisplatin treatment and is for leading to of apoptosis. of ATM in the a mechanism to DNA damage and apoptosis. results demonstrate the of DNA-PK during cisplatin treatment of renal tubular cells, an that is with results by PubMed Scopus Google Scholar). ATM and DNA-PK are we show that ATR is activated by cisplatin in renal tubular cells and tissues. The ATR activation is not by a of but by the of ATR in nuclear with phosphorylated H2AX, a of DNA damage the of ATR during cisplatin treatment is not is in with the that ATR activation is by its in nuclear foci during 2001; PubMed Scopus Google Scholar). is ATR is specifically activated during cisplatin treatment. we demonstrate the of the in the is with and ATR, the of a In ATM not with following cisplatin treatment. is that the ATR activation by cisplatin to the and and of signaling at DNA damage is by the of DNA damage by or K.A. DNA PubMed Scopus Google Scholar, S.J. Full Text Full Text PDF PubMed Scopus Google Scholar). in a and of the signaling protein that are at the of DNA Downstream of ATR, we show that both Chk1 and Chk2 are phosphorylated during cisplatin treatment. Chk1 at and are to for J. 2003; PubMed Scopus Google Scholar). Interestingly, we show that early of Chk1 is by Chk1 and both are by dominant-negative ATR Chk1 following cisplatin treatment is that of Chk1 during treatment not to Chk1 activation but to its via the pathway W. 2005; Full Text Full Text PDF PubMed Scopus (235) Google Scholar). Consistently, we demonstrate for a role of the pathway in Chk1 during cisplatin treatment the Chk1 following activation not a role for Chk1 in cisplatin-induced DNA damage response and apoptosis. we show that Chk1 not p53 activation In cisplatin-induced apoptosis is not by Chk1 Together, the results suggest that Chk1 not a role in the DNA damage response during cisplatin treatment. Chk2 is not to Chk1 but has with the J. M. C. DNA 2004; PubMed Scopus Google Scholar). Chk2 is activated by at J. M. C. DNA 2004; PubMed Scopus Google Scholar). phosphorylation, the Chk2 leading to J. M. C. DNA 2004; PubMed Scopus Google Scholar). Chk2 is to phosphorylated and activated by ATM J. M. C. DNA 2004; PubMed Scopus Google Scholar, A. A. G. P.M. A.J. A. H. R.G. P.A. S.J. Biol. 2002; 22: PubMed Scopus Google Scholar). However, ATR-dependent activation of Chk2 has been Yang S. H. N. J. Biol. Chem. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar). results show during cisplatin Chk2 is phosphorylated at and activated in an ATR-dependent we show that Chk2 is activated in vivo during cisplatin nephrotoxicity. ATR and Chk2 for signaling during cisplatin-induced we show that signaling is largely for p53 and activation during cisplatin treatment and As a result, of by dominant-negative or p53 activation the and Recent and suggested a role for p53 in tubular cell apoptosis and cisplatin nephrotoxicity (10Cummings B.S. Schnellmann R.G. J. Pharmacol. Exp. Ther. 2002; 302: 8-17Crossref PubMed Scopus (313) Google Scholar, 15Jiang M. Yi X. Hsu S. Wang C.Y. Dong Z. Am. J. Physiol. 2004; 287: F1140-F1147Crossref PubMed Scopus (148) Google Scholar, 16Seth R. Yang C. Kaushal V. Shah S.V. Kaushal G.P. J. Biol. Chem. 2005; 280: 31230-31239Abstract Full Text Full Text PDF PubMed Scopus (156) Google Scholar, 17Wei Q. Dong G. Yang Megyesi J. Price P.M. Dong Z. Am. J. Physiol. PubMed Scopus Google Scholar). work has that are cisplatin-induced nephrotoxicity in the is but and Q. Dong G. Yang Megyesi J. Price P.M. Dong Z. Am. J. Physiol. PubMed Scopus Google Scholar). The has a of the pathway that to p53 activation the the of the pathway, we that the and are suppressed ATR or Chk2 is and remains to and to to the of renal injury in In we for activation in vivo during cisplatin nephrotoxicity the ATR-Chk2 pathway a for renoprotection during cisplatin chemotherapy in cancer that renal injury by However, remains the therapeutic effects of cisplatin in or cancer that ATR in cancer cell the cells to a role for ATR in cancer cells D. Ther. PubMed Scopus Google Scholar). suggested that ATR a or role in cells p53 Full Text Full Text PDF PubMed Scopus Google a for of suggested by and ATR signaling is in cancer cells in kidneys, of ATR an effective for renoprotection during cancer therapy with cisplatin and its We at The at the of at in and Wang at for cell and

Renal ischemia-reperfusion leads to acute kidney injury (AKI), a major kidney disease associated with an increasing prevalence and high mortality rates. A variety of experimental models, both in vitro and in vivo, have been used to study the pathogenic mechanisms of ischemic AKI and to test renoprotective strategies. Among them, the mouse model of renal clamping is popular, mainly due to the availability of transgenic models and the relatively small animal size for drug testing. However, the mouse model is generally less stable, resulting in notable variations in results. Here, we describe a detailed protocol of the mouse model of bilateral renal ischemia-reperfusion. We share the lessons and experiences gained from our laboratory in the past decade. We further discuss the technical issues that account for the variability of this model and offer relevant solutions, which may help other investigators to establish a well-controlled, reliable animal model of ischemic AKI.

Damaged or dysfunctional mitochondria are toxic to the cell by producing reactive oxygen species and releasing cell death factors. Therefore, timely removal of these organelles is critical to cellular homeostasis and viability. Mitophagy is the mechanism of selective degradation of mitochondria via autophagy. The significance of mitophagy in kidney diseases, including ischemic acute kidney injury (AKI), has yet to be established, and the involved pathway of mitophagy remains poorly understood. Here, we show that mitophagy is induced in renal proximal tubular cells in both in vitro and in vivo models of ischemic AKI. Mitophagy under these conditions is abrogated by Pink1 and Park2 deficiency, supporting a critical role of the PINK1-PARK2 pathway in tubular cell mitophagy. Moreover, ischemic AKI is aggravated in pink1 andpark2 single- as well as double-knockout mice. Mechanistically, Pink1 and Park2 deficiency enhances mitochondrial damage, reactive oxygen species production, and inflammatory response. Taken together, these results indicate that PINK1-PARK2-mediated mitophagy plays an important role in mitochondrial quality control, tubular cell survival, and renal function during AKI.

Angiogenesis, a new vessel formation from the pre-existing ones, is essential for embryonic development, wound repair and treatment of ischemic heart and limb diseases. However, dysregulated angiogenesis contributes to various pathologies such as diabetic retinopathy, atherosclerosis and cancer. Reactive oxygen species (ROS) derived from NADPH oxidase (NOX) as well as mitochondria play an important role in promoting the angiogenic switch from quiescent endothelial cells (ECs). However, how highly diffusible ROS produced from different sources and location can communicate with each other to regulate angiogenesis remains unclear. To detect a localized ROS signal in distinct subcellular compartments in real time in situ, compartment-specific genetically encoded redox-sensitive fluorescence biosensors have been developed. Recently, the intercellular communication, "cross-talk", between ROS derived from NOX and mitochondria, termed "ROS-induced ROS release", has been proposed as a mechanism for ROS amplification at distinct subcellular compartments, which are essential for activation of redox signaling. This "ROS-induced ROS release" may represent a feed-forward mechanism of localized ROS production to maintain sustained signaling, which can be targeted under pathological conditions with oxidative stress or enhanced to promote therapeutic angiogenesis. In this review, we summarize the recent knowledge regarding the role of the cross-talk between NOX and mitochondria organizing the sustained ROS signaling involved in VEGF signaling, neovascularization and tissue repair.

I t is now appreciated that emerging therapeutic strategies for recovery must include the cerebral vasculature and that induction of angiogenesis will stimulate endogenous recovery mechanisms, including neurogenesis, synaptogenesis, and neuronal and synaptic plasticity. These events are all involved in the long-term repair and restoration process of the brain after an ischemic event. Several recent excellent reviews provided detailed information on the mechanisms and molecular targets for angiogenesis after stroke. The purpose of this review is to evaluate the evidence that angiogenesis is a target for recovery after an ischemic stroke.

BACKGROUND: Pancreatic cancer is one of the cancers where anti-PD-L1/PD-1 immunotherapy has been unsuccessful. What confers pancreatic cancer resistance to checkpoint immunotherapy is unknown. The aim of this study is to elucidate the underlying mechanism of PD-L1 expression regulation in the context of pancreatic cancer immune evasion. METHODS: Pancreatic cancer mouse models and human specimens were used to determine PD-L1 and PD-1 expression and cancer immune evasion. Histone methyltransferase inhibitors, RNAi, and overexpression were used to elucidate the underlying molecular mechanism of PD-L1 expression regulation. All statistical tests were two-sided. RESULTS: PD-L1 is expressed in 60% to 90% of tumor cells in human pancreatic carcinomas and in nine of 10 human pancreatic cancer cell lines. PD-1 is expressed in 51.2% to 52.1% of pancreatic tumor-infiltrating cytotoxic T lymphocytes (CTLs). Tumors grow statistically significantly faster in FasL-deficient mice than in wild-type mice (P = .03-.001) and when CTLs are neutralized (P = .03-<.001). H3K4 trimethylation (H3K4me3) is enriched in the cd274 promoter in pancreatic tumor cells. MLL1 directly binds to the cd274 promoter to catalyze H3K4me3 to activate PD-L1 transcription in tumor cells. Inhibition or silencing of MLL1 decreases the H3K4me3 level in the cd274 promoter and PD-L1 expression in tumor cells. Accordingly, inhibition of MLL1 in combination with anti-PD-L1 or anti-PD-1 antibody immunotherapy effectively suppresses pancreatic tumor growth in a FasL- and CTL-dependent manner. CONCLUSIONS: The Fas-FasL/CTLs and the MLL1-H3K4me3-PD-L1 axis play contrasting roles in pancreatic cancer immune surveillance and evasion. Targeting the MLL1-H3K4me3 axis is an effective approach to enhance the efficacy of checkpoint immunotherapy against pancreatic cancer.

The usefulness and efficacy of cisplatin, a chemotherapeutic drug, are limited by its toxicity to normal tissues and organs, including the kidneys. The uptake of cisplatin in renal tubular cells is high, leading to cisplatin accumulation and tubular cell injury and death, culminating in acute renal failure. While extensive investigations have been focused on the signaling pathways of cisplatin nephrotoxicity, much less is known about the mechanism of cisplatin uptake by renal cells and tissues. In this regard, evidence has been shown for the involvement of organic cation transporters (OCT), specifically OCT2. The copper transporter Ctr1 is highly expressed in the renal tubular cells; however, its role in cisplatin nephrotoxicity is not known. In this study, we demonstrate that Ctr1 is mainly expressed in both proximal and distal tubular cells in mouse kidneys. We further show that Ctr1 is mainly localized on the basolateral side of these cells, a proposed site for cisplatin uptake. Importantly, downregulation of Ctr1 by small interfering RNA or copper pretreatment results in decreased cisplatin uptake. Consistently, downregulation of Ctr1 suppresses cisplatin toxicity, including cell death by both apoptosis and necrosis. Cimetidine, a pharmacological inhibitor of OCT2, can also partially attenuate cisplatin uptake. Notably, cimetidine can further reduce cisplatin uptake and cisplatin toxicity in Ctr1-downregulated cells. The results have demonstrated the first evidence for a role of Ctr1 in cisplatin uptake and nephrotoxicity.

Brain-derived neurotrophic factor (BDNF), which plays an important role in neurodevelopmental plasticity and cognitive performance, has been implicated in neuropsychopathology of schizophrenia. We examined the levels of both cerebrospinal fluid (CSF) and plasma BDNF concomitantly in drug-naive first-episode psychotic (FEP) subjects with ELISA to determine if these levels were different from control values and if any correlation exists between CSF and plasma BDNF levels. A significant reduction in BDNF protein levels was observed in both plasma and CSF of FEP subjects compared to controls. BDNF levels showed significant negative correlation with the scores of baseline PANSS positive symptom subscales. In addition, there was a significant positive correlation between plasma and CSF BDNF levels in FEP subjects. The parallel changes in BDNF levels in plasma and CSF indicate that plasma BDNF levels reflect the brain changes in BDNF levels in schizophrenia.

Vacuolar protein sorting-35 (VPS35) is essential for endosome-to-Golgi retrieval of membrane proteins. Mutations in the VPS35 gene have been identified in patients with autosomal dominant PD. However, it remains poorly understood if and how VPS35 deficiency or mutation contributes to PD pathogenesis. Here we provide evidence that links VPS35 deficiency to PD-like neuropathology. VPS35 was expressed in mouse dopamine (DA) neurons in substantia nigra pars compacta (SNpc) and STR (striatum)--regions that are PD vulnerable. VPS35-deficient mice exhibited PD-relevant deficits including accumulation of α-synuclein in SNpc-DA neurons, loss of DA transmitter and DA neurons in SNpc and STR, and impairment of locomotor behavior. Further mechanical studies showed that VPS35-deficient DA neurons or DA neurons expressing PD-linked VPS35 mutant (D620N) had impaired endosome-to-Golgi retrieval of lysosome-associated membrane glycoprotein 2a (Lamp2a) and accelerated Lamp2a degradation. Expression of Lamp2a in VPS35-deficient DA neurons reduced α-synuclein, supporting the view for Lamp2a as a receptor of chaperone-mediated autophagy to be critical for α-synuclein degradation. These results suggest that VPS35 deficiency or mutation promotes PD pathogenesis and reveals a crucial pathway, VPS35-Lamp2a-α-synuclein, to prevent PD pathogenesis. Significance statement: VPS35 is a key component of the retromer complex that is essential for endosome-to-Golgi retrieval of membrane proteins. Mutations in the VPS35 gene have been identified in patients with PD. However, if and how VPS35 deficiency or mutation contributes to PD pathogenesis remains unclear. We demonstrated that VPS35 deficiency or mutation (D620N) in mice leads to α-synuclein accumulation and aggregation in the substantia nigra, accompanied with DA neurodegeneration. VPS35-deficient DA neurons exhibit impaired endosome-to-Golgi retrieval of Lamp2a, which may contribute to the reduced α-synuclein degradation through chaperone-mediated autophagy. These results suggest that VPS35 deficiency or mutation promotes PD pathogenesis, and reveals a crucial pathway, VPS35-Lamp2a-α-synuclein, to prevent PD pathogenesis.

Vacuolar protein sorting-35 (VPS35) is a retromer component for endosomal trafficking. Mutations of VPS35 have been linked to familial Parkinson's disease (PD). Here, we show that specific deletion of the VPS35 gene in dopamine (DA) neurons resulted in PD-like deficits, including loss of DA neurons and accumulation of α-synuclein. Intriguingly, mitochondria became fragmented and dysfunctional in VPS35-deficient DA neurons, phenotypes that could be restored by expressing VPS35 wild-type, but not PD-linked mutant. Concomitantly, VPS35 deficiency or mutation increased mitochondrial E3 ubiquitin ligase 1 (MUL1) and, thus, led to mitofusin 2 (MFN2) degradation and mitochondrial fragmentation. Suppression of MUL1 expression ameliorated MFN2 reduction and DA neuron loss but not α-synuclein accumulation. These results provide a cellular mechanism for VPS35 dysfunction in mitochondrial impairment and PD pathogenesis.

Acute kidney injury (AKI) is a major kidney disease characterized by an abrupt loss of renal function. Accumulating evidence indicates that incomplete or maladaptive repair after AKI can result in kidney fibrosis and the development and progression of chronic kidney disease (CKD). Hypoxia, a condition of insufficient supply of oxygen to cells and tissues, occurs in both acute and chronic kidney diseases under a variety of clinical and experimental conditions. Hypoxia-inducible factors (HIFs) are the "master" transcription factors responsible for gene expression in hypoxia. Recent researches demonstrate that HIFs play an important role in kidney injury and repair by regulating HIF target genes, including microRNAs. However, there are controversies regarding the pathological roles of HIFs in kidney injury and repair. In this review, we describe the regulation, expression, and functions of HIFs, and their target genes and related functions. We also discuss the involvement of HIFs in AKI and kidney repair, presenting HIFs as effective therapeutic targets.

Angiogenesis, a process of new blood vessel formation, is a prerequisite for tumour growth to supply the proliferating tumour with oxygen and nutrients. The angiogenic process may contribute to tumour progression, invasion and metastasis, and is generally accepted as an indicator of tumour prognosis. Therefore, targeting tumour angiogenesis has become of high clinical relevance. The current review aimed to highlight mechanistic details of anti-angiogenic therapies and how they relate to classification and treatment rationales. Angiogenesis inhibitors are classified into either direct inhibitors that target endothelial cells in the growing vasculature or indirect inhibitors that prevent the expression or block the activity of angiogenesis inducers. The latter class extends to include targeted therapy against oncogenes, conventional chemotherapeutic agents and drugs targeting other cells of the tumour micro-environment. Angiogenesis inhibitors may be used as either monotherapy or in combination with other anticancer drugs. In this context, many preclinical and clinical studies revealed higher therapeutic effectiveness of the combined treatments compared with individual treatments. The proper understanding of synergistic treatment modalities of angiogenesis inhibitors as well as their wide range of cellular targets could provide effective tools for future therapies of many types of cancer.