Institute of Laboratory Animal Science

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in an unprecedented public health crisis. Because of the novelty of the virus, there are currently no SARS-CoV-2-specific treatments or vaccines available. Therefore, rapid development of effective vaccines against SARS-CoV-2 are urgently needed. Here, we developed a pilot-scale production of PiCoVacc, a purified inactivated SARS-CoV-2 virus vaccine candidate, which induced SARS-CoV-2-specific neutralizing antibodies in mice, rats, and nonhuman primates. These antibodies neutralized 10 representative SARS-CoV-2 strains, suggesting a possible broader neutralizing ability against other strains. Three immunizations using two different doses, 3 or 6 micrograms per dose, provided partial or complete protection in macaques against SARS-CoV-2 challenge, respectively, without observable antibody-dependent enhancement of infection. These data support the clinical development and testing of PiCoVacc for use in humans.

The recent outbreak of coronavirus disease (COVID-19) caused by SARS-CoV-2 infection in Wuhan, China has posed a serious threat to global public health. To develop specific anti-coronavirus therapeutics and prophylactics, the molecular mechanism that underlies viral infection must first be defined. Therefore, we herein established a SARS-CoV-2 spike (S) protein-mediated cell-cell fusion assay and found that SARS-CoV-2 showed a superior plasma membrane fusion capacity compared to that of SARS-CoV. We solved the X-ray crystal structure of six-helical bundle (6-HB) core of the HR1 and HR2 domains in the SARS-CoV-2 S protein S2 subunit, revealing that several mutated amino acid residues in the HR1 domain may be associated with enhanced interactions with the HR2 domain. We previously developed a pan-coronavirus fusion inhibitor, EK1, which targeted the HR1 domain and could inhibit infection by divergent human coronaviruses tested, including SARS-CoV and MERS-CoV. Here we generated a series of lipopeptides derived from EK1 and found that EK1C4 was the most potent fusion inhibitor against SARS-CoV-2 S protein-mediated membrane fusion and pseudovirus infection with IC50s of 1.3 and 15.8 nM, about 241- and 149-fold more potent than the original EK1 peptide, respectively. EK1C4 was also highly effective against membrane fusion and infection of other human coronavirus pseudoviruses tested, including SARS-CoV and MERS-CoV, as well as SARSr-CoVs, and potently inhibited the replication of 5 live human coronaviruses examined, including SARS-CoV-2. Intranasal application of EK1C4 before or after challenge with HCoV-OC43 protected mice from infection, suggesting that EK1C4 could be used for prevention and treatment of infection by the currently circulating SARS-CoV-2 and other emerging SARSr-CoVs.

BACKGROUND: Human infections with zoonotic coronaviruses (CoVs), including severe acute respiratory syndrome (SARS)-CoV and Middle East respiratory syndrome (MERS)-CoV, have raised great public health concern globally. Here, we report a novel bat-origin CoV causing severe and fatal pneumonia in humans. METHODS: We collected clinical data and bronchoalveolar lavage (BAL) specimens from five patients with severe pneumonia from Wuhan Jinyintan Hospital, Hubei province, China. Nucleic acids of the BAL were extracted and subjected to next-generation sequencing. Virus isolation was carried out, and maximum-likelihood phylogenetic trees were constructed. RESULTS: Five patients hospitalized from December 18 to December 29, 2019 presented with fever, cough, and dyspnea accompanied by complications of acute respiratory distress syndrome. Chest radiography revealed diffuse opacities and consolidation. One of these patients died. Sequence results revealed the presence of a previously unknown β-CoV strain in all five patients, with 99.8% to 99.9% nucleotide identities among the isolates. These isolates showed 79.0% nucleotide identity with the sequence of SARS-CoV (GenBank NC_004718) and 51.8% identity with the sequence of MERS-CoV (GenBank NC_019843). The virus is phylogenetically closest to a bat SARS-like CoV (SL-ZC45, GenBank MG772933) with 87.6% to 87.7% nucleotide identity, but is in a separate clade. Moreover, these viruses have a single intact open reading frame gene 8, as a further indicator of bat-origin CoVs. However, the amino acid sequence of the tentative receptor-binding domain resembles that of SARS-CoV, indicating that these viruses might use the same receptor. CONCLUSION: A novel bat-borne CoV was identified that is associated with severe and fatal respiratory disease in humans.

Coronaviruses (CoVs) have formerly been regarded as relatively harmless respiratory pathogens to humans. However, two outbreaks of severe respiratory tract infection, caused by the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), as a result of zoonotic CoVs crossing the species barrier, caused high pathogenicity and mortality rates in human populations. This brought CoVs global attention and highlighted the importance of controlling infectious pathogens at international borders. In this review, we focus on our current understanding of the epidemiology, pathogenesis, prevention, and treatment of SARS-CoV and MERS-CoV, as well as provides details on the pivotal structure and function of the spike proteins (S proteins) on the surface of each of these viruses. For building up more suitable animal models, we compare the current animal models recapitulating pathogenesis and summarize the potential role of host receptors contributing to diverse host affinity in various species. We outline the research still needed to fully elucidate the pathogenic mechanism of these viruses, to construct reproducible animal models, and ultimately develop countermeasures to conquer not only SARS-CoV and MERS-CoV, but also these emerging coronaviral diseases.

The gut microbiota, the largest symbiotic ecosystem with the host, has been shown to play important roles in maintaining intestinal homeostasis. Dysbiosis of the gut microbiome is caused by the imbalance between the commensal and pathogenic microbiomes. The commensal microbiome regulates the maturation of the mucosal immune system, while the pathogenic microbiome causes immunity dysfunction, resulting in disease development. The gut mucosal immune system, which consists of lymph nodes, lamina propria and epithelial cells, constitutes a protective barrier for the integrity of the intestinal tract. The composition of the gut microbiota is under the surveillance of the normal mucosal immune system. Inflammation, which is caused by abnormal immune responses, influences the balance of the gut microbiome, resulting in intestinal diseases. In this review, we briefly outlined the interaction between the gut microbiota and the immune system and provided a reference for future studies.

Newly emerging viruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV), Middle Eastern respiratory syndrome CoVs (MERS-CoV), and H7N9, cause fatal acute lung injury (ALI) by driving hypercytokinemia and aggressive inflammation through mechanisms that remain elusive. In SARS-CoV/macaque models, we determined that anti-spike IgG (S-IgG), in productively infected lungs, causes severe ALI by skewing inflammation-resolving response. Alveolar macrophages underwent functional polarization in acutely infected macaques, demonstrating simultaneously both proinflammatory and wound-healing characteristics. The presence of S-IgG prior to viral clearance, however, abrogated wound-healing responses and promoted MCP1 and IL-8 production and proinflammatory monocyte/macrophage recruitment and accumulation. Critically, patients who eventually died of SARS (hereafter referred to as deceased patients) displayed similarly accumulated pulmonary proinflammatory, absence of wound-healing macrophages, and faster neutralizing antibody responses. Their sera enhanced SARS-CoV-induced MCP1 and IL-8 production by human monocyte-derived wound-healing macrophages, whereas blockade of FcγR reduced such effects. Our findings reveal a mechanism responsible for virus-mediated ALI, define a pathological consequence of viral specific antibody response, and provide a potential target for treatment of SARS-CoV or other virus-mediated lung injury.

This article reviews and summarizes 200 years of Parkinson's disease. It comprises a relevant history of Dr. James Parkinson's himself and what he described accurately and what he missed from today's perspective. Parkinson's disease today is understood as a multietiological condition with uncertain etiopathogenesis. Many advances have occurred regarding pathophysiology and symptomatic treatments, but critically important issues are still pending resolution. Among the latter, the need to modify disease progression is undoubtedly a priority. In sum, this multiple-author article, prepared to commemorate the bicentenary of the shaking palsy, provides a historical state-of-the-art account of what has been achieved, the current situation, and how to progress toward resolving Parkinson's disease. © 2017 International Parkinson and Movement Disorder Society.

The differentiation capacity of human embryonic stem cells (hESCs) holds great promise for therapeutic applications. We report a novel three-stage method to efficiently direct the differentiation of human embryonic stem cells into hepatic cells in serum-free medium. Human ESCs were first differentiated into definitive endoderm cells by 3 days of Activin A treatment. Next, the presence of fibroblast growth factor-4 and bone morphogenetic protein-2 in the culture medium for 5 days induced efficient hepatic differentiation from definitive endoderm cells. Approximately 70% of the cells expressed the hepatic marker albumin. After 10 days of further in vitro maturation, these cells expressed the adult liver cell markers tyrosine aminotransferase, tryptophan oxygenase 2, phosphoenolpyruvate carboxykinase (PEPCK), Cyp7A1, Cyp3A4 and Cyp2B6. Furthermore, these cells exhibited functions associated with mature hepatocytes including albumin secretion, glycogen storage, indocyanine green, and low-density lipoprotein uptake, and inducible cytochrome P450 activity. When transplanted into CCl4 injured severe combined immunodeficiency mice, these cells integrated into the mouse liver and expressed human alpha-1 antitrypsin for at least 2 months. In addition, we found that the hESC-derived hepatic cells were readily infected by human immunodeficiency virus-hepatitis C virus pseudotype viruses. Conclusion: We have developed an efficient way to direct the differentiation of human embryonic stem cells into cells that exhibit characteristics of mature hepatocytes. Our studies should facilitate searching the molecular mechanisms underlying human liver development, and form the basis for hepatocyte transplantation and drug tests. (HEPATOLOGY 2007;45:1229–1239.)

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe disease in human with an overall case-fatality rate of >35%. Effective antivirals are crucial for improving the clinical outcome of MERS. Although a number of repurposed drugs, convalescent-phase plasma, antiviral peptides, and neutralizing antibodies exhibit anti-MERS-CoV activity in vitro, most are not readily available or have not been evaluated in nonhuman primates. We assessed 3 repurposed drugs with potent in vitro anti-MERS-CoV activity (mycophenolate mofetil [MMF], lopinavir/ritonavir, and interferon-β1b) in common marmosets with severe disease resembling MERS in humans. The lopinavir/ritonavir-treated and interferon-β1b-treated animals had better outcome than the untreated animals, with improved clinical (mean clinical scores ↓50.9%-95.0% and ↓weight loss than the untreated animals), radiological (minimal pulmonary infiltrates), and pathological (mild bronchointerstitial pneumonia) findings, and lower mean viral loads in necropsied lung (↓0.59-1.06 log10 copies/glyceraldehyde 3-phosphate dehydrogenase [GAPDH]; P < .050) and extrapulmonary (↓0.11-1.29 log10 copies/GAPDH; P < .050 in kidney) tissues. In contrast, all MMF-treated animals developed severe and/or fatal disease with higher mean viral loads (↑0.15-0.54 log10 copies/GAPDH) than the untreated animals. The mortality rate at 36 hours postinoculation was 67% (untreated and MMF-treated) versus 0-33% (lopinavir/ritonavir-treated and interferon-β1b-treated). Lopinavir/ritonavir and interferon-β1b alone or in combination should be evaluated in clinical trials. MMF alone may worsen MERS and should not be used.

Abstract Cigarette smoking is a major risk factor for atherosclerosis and other cardiovascular diseases. Increasing evidence has demonstrated that nicotine impairs the cardiovascular system by targeting vascular endothelial cells, but the underlying mechanisms remain obscure. It is known that cell death and inflammation are crucial processes leading to atherosclerosis. We proposed that pyroptosis may be implicated in nicotine-induced atherosclerosis and therefore conducted the present study. We found that nicotine resulted in larger atherosclerotic plaques and secretion of inflammatory cytokines in ApoE −/− mice fed with a high-fat diet (HFD). Treatment of human aortic endothelial cells (HAECs) with nicotine resulted in NLRP3-ASC inflammasome activation and pyroptosis, as evidenced by cleavage of caspase-1, production of downstream interleukin (IL)-1β and IL-18, and elevation of LDH activity and increase of propidium iodide (PI) positive cells, which were all inhibited by caspase-1 inhibitor. Moreover, silencing NLRP3 or ASC by small interfering RNA efficiently suppressed nicotine-induced caspase-1 cleavage, IL-18 and IL-1β production, and pyroptosis in HAECs. Further experiments revealed that the nicotine-NLRP3-ASC-pyroptosis pathway was activated by reactive oxygen species (ROS), since ROS scavenger (N-acetyl-cysteine, NAC) prevented endothelial cell pyroptosis. We conclude that pyroptosis is likely a cellular mechanism for the pro-atherosclerotic property of nicotine and stimulation of ROS to activate NLRP3 inflammasome is a signaling mechanism for nicotine-induced pyroptosis.

General anesthetics are widely used in clinical practice. On the molecular level, these compounds have been shown to modulate the activity of various neuronal ion channels. However, the functional relevance of identified sites in mediating essential components of the general anesthetic state, such as immobility and hypnosis, is still unknown. Using gene-targeting technology, we generated mice harboring a subtle point mutation (N265M) in the second transmembrane region of the beta3 subunit of the GABA(A) receptor. In these mice, the suppression of noxious-evoked movements in response to the intravenous anesthetics etomidate and propofol is completely abolished, while only slightly decreased with the volatile anesthetics enflurane and halothane. beta3(N265M) mice also display a profound reduction in the loss of righting reflex duration in response to intravenous but not volatile anesthetics. In addition, electrophysiological recordings revealed that anesthetic agents were significantly less effective in enhancing GABA(A) receptor-mediated currents, and in decreasing spontaneous action potential firing in cortical brain slices derived from mutant mice. Taken together, our results demonstrate that a single molecular target, and indeed a specific residue (N265) located within the GABA(A) receptor beta3 subunit, is a major determinant of behavioral responses evoked by the intravenous anesthetics etomidate and propofol, whereas volatile anesthetics appear to act via a broader spectrum of molecular targets.

Coronavirus disease 2019 (COVID-19), which is caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic. It is unclear whether convalescing patients have a risk of reinfection. We generated a rhesus macaque model of SARS-CoV-2 infection that was characterized by interstitial pneumonia and systemic viral dissemination mainly in the respiratory and gastrointestinal tracts. Rhesus macaques reinfected with the identical SARS-CoV-2 strain during the early recovery phase of the initial SARS-CoV-2 infection did not show detectable viral dissemination, clinical manifestations of viral disease, or histopathological changes. Comparing the humoral and cellular immunity between primary infection and rechallenge revealed notably enhanced neutralizing antibody and immune responses. Our results suggest that primary SARS-CoV-2 exposure protects against subsequent reinfection in rhesus macaques.

Middle East respiratory syndrome (MERS) is associated with a mortality rate of >35%. We previously showed that MERS coronavirus (MERS-CoV) could infect human macrophages and dendritic cells and induce cytokine dysregulation. Here, we further investigated the interplay between human primary T cells and MERS-CoV in disease pathogenesis. Importantly, our results suggested that MERS-CoV efficiently infected T cells from the peripheral blood and from human lymphoid organs, including the spleen and the tonsil. We further demonstrated that MERS-CoV infection induced apoptosis in T cells, which involved the activation of both the extrinsic and intrinsic apoptosis pathways. Remarkably, immunostaining of spleen sections from MERS-CoV-infected common marmosets demonstrated the presence of viral nucleoprotein in their CD3(+) T cells. Overall, our results suggested that the unusual capacity of MERS-CoV to infect T cells and induce apoptosis might partly contribute to the high pathogenicity of the virus.

The shedding of severe acute respiratory syndrome coronavirus (SARS-CoV) into saliva droplets plays a critical role in viral transmission. The source of high viral loads in saliva, however, remains elusive. Here we investigate the early target cells of infection in the entire array of respiratory tissues in Chinese macaques after intranasal inoculations with a single-cycle pseudotyped virus and a pathogenic SARS-CoV. We found that angiotensin-converting enzyme 2-positive (ACE2(+)) cells were widely distributed in the upper respiratory tract, and ACE2(+) epithelial cells lining salivary gland ducts were the early target cells productively infected. Our findings also have implications for SARS-CoV early diagnosis and prevention.

Experimental evidence supporting 1,1'-dimethyl-4,4'-bipyridinium [paraquat (PQ)] as a risk factor for Parkinson's disease (PD) is equivocal. Other agricultural chemicals, including dithiocarbamate fungicides such as manganese ethylenebisdithiocarbamate [maneb (MB)], are widely used in the same geographical regions as paraquat and also impact dopamine systems, suggesting that mixtures may be more relevant etiological models. This study therefore proposed that combined PQ and MB exposures would produce greater effects on dopamine (DA) systems than would either compound administered alone. Male C57BL/6 mice were treated twice a week for 6 weeks with intraperitoneal saline, 10 mg/kg paraquat, 30 mg/kg maneb, or their combination (PQ + MB). MB, but not PQ, reduced motor activity immediately after treatment, and this effect was potentiated by combined PQ + MB treatment. As treatments progressed, only the combined PQ + MB group evidenced a failure of motor activity levels to recover within 24 hr. Striatal DA and dihydroxyphenylacetic acid increased 1-3 d and decreased 7 d after injections. Only PQ + MB reduced tyrosine hydroxylase (TH) and DA transporter immunoreactivity and did so in dorsal striatum but not nucleus accumbens. Correspondingly, striatal TH protein levels were decreased only by combined PQ + MB 5 d after injection. Reactive gliosis occurred only in response to combined PQ + MB in dorsal-medial but not ventral striatum. TH immunoreactivity and cell counts were reduced only by PQ + MB and in the substantia nigra but not ventral tegmental area. These synergistic effects of combined PQ + MB, preferentially expressed in the nigrostriatal DA system, suggest that such mixtures could play a role in the etiology of PD.

The topic of gut microbiota is currently attracting considerable interest as a potential factor in Alzheimer's disease (AD). However, the extent and time course of alterations in the gut microbiota, and their effects on AD pathology remain uncertain. Herein, we compared the fecal microbiomes and fecal short chain fatty acid composition (SCFAs) between wild-type and AD model mice at different ages under strictly controlled specific pathogen free conditions, and also conducted microscopic investigations of intestinal structures. Our results showed that the microbiota composition and diversity were perturbed and the level of SCFAs was reduced in AD mice, predicting alterations in more than 30 metabolic pathways, which may be associated with amyloid deposition and ultrastructural abnormalities in AD mouse intestine. These findings indicate that AD pathology might not only affect brain function directly, but also exacerbate cognitive deficits through reducing the level of SCFAs via alterations of gut microbiota induced by intestinal amyloid deposition. Our data may support a role of gut microbiota, and suggest a novel route for therapeutic intervention in AD.

Prostate cancer (CaP) forms osteoblastic skeletal metastases with an underlying osteoclastic component. However, the importance of osteoclastogenesis in the development of CaP skeletal lesions is unknown. In the present study, we demonstrate that CaP cells directly induce osteoclastogenesis from osteoclast precursors in the absence of underlying stroma in vitro. CaP cells produced a soluble form of receptor activator of NF-kappaB ligand (RANKL), which accounted for the CaP-mediated osteoclastogenesis. To evaluate for the importance of osteoclastogenesis on CaP tumor development in vivo, CaP cells were injected both intratibially and subcutaneously in the same mice, followed by administration of the decoy receptor for RANKL, osteoprotegerin (OPG). OPG completely prevented the establishment of mixed osteolytic/osteoblastic tibial tumors, as were observed in vehicle-treated animals, but it had no effect on subcutaneous tumor growth. Consistent with the role of osteoclasts in tumor development, osteoclast numbers were elevated at the bone/tumor interface in the vehicle-treated mice compared with the normal values in the OPG-treated mice. Furthermore, OPG had no effect on CaP cell viability, proliferation, or basal apoptotic rate in vitro. These results emphasize the important role that osteoclast activity plays in the establishment of CaP skeletal metastases, including those with an osteoblastic component.

Acne inversa (AI), also known as hidradenitis suppurativa, is a chronic, recurrent, inflammatory disease of hair follicles that often runs in families. We studied six Chinese families with features of AI as well as additional skin lesions on back, face, nape, and waist and found independent loss-of-function mutations in PSENEN, PSEN1, or NCSTN, the genes encoding essential components of the γ-secretase multiprotein complex. Our results identify the γ-secretase component genes as the culprits for a subset of familial AI, implicate the γ-secretase-Notch pathway in the molecular pathogenesis of AI, and demonstrate that familial AI can be an allelic disorder of early-onset familial Alzheimer's disease.

Virtually of the all recent therapeutic interventions for treating sepsis have failed to improve survival. One potential explanation is that the heterogeneity of the immune response to the septic challenge is such that only a portion of the patients die as a result of excessive inflammation. The clinical trials lacked power because traditional measurements do not accurately identify these patients. Previous work has shown that higher levels of interleukin (IL)-6 are found in those mice that die from septic peritonitis; therefore, we sought to determine whether IL-6 measured 6 h after surgery could predict outcome. Adult, female BALB/c mice (n = 79) were subjected to cecal ligation and puncture with a 21-gauge needle and treated with imipenem in D5W every 12 h for 5 days, resulting in a homogenous population at the outset. Six hours after surgery, 20 microL of blood was obtained from the tail vein to measure IL-6. Mortality was followed for 21 days. Overall 3-day survival was 77%, and 21-day mortality was 56%. Plasma IL-6 levels >2,000 pg/mL were determined to predict mortality within the first 3 days with a sensitivity of 58% and specificity of 97%. To further refine the mortality prediction, body weight and a complete blood count were performed 24 hours after cecal ligation and puncture. Discriminate analysis indicated that a weighted formula combining body mass, lymphocyte, and platelet count would predict death with sensitivity of 83% and a specificity of 79%. We tested the value of the IL-6 prediction by surgically resecting the cecum in those animals with IL-6 > 2000 pg/mL, which resulted in a significant improvement in survival. These data demonstrate that IL-6 measured 6 h after injury accurately predicts mortality resulting from experimental sepsis. This measurement may be determined quickly so that therapy may be targeted only to those individuals at significant risk of dying and initiated within sufficient time to be effective.

Con A-induced hepatitis (Con A-hepatitis) is a hepatitis model in which hepatic injury is supposed to be caused by cytokines from activated T cells. To elucidate the pathogenesis of this disease, we analyzed the roles of IFN-gamma and TNF-alpha using deficient mice of these cytokines. Development of hepatitis was reduced significantly in IFN-gamma(-/-) mice, while susceptibility of TNF-alpha(-/-) mice was not changed. Interestingly, apoptotic cell death was observed in the affected livers of control or TNF-alpha(-/-) mice, but not in those of IFN-gamma(-/-) mice. Fas mRNA expression was increased in the livers of hepatitis mice, but less abundantly in those of IFN-gamma(-/-) mice. Since apoptosis of liver cells was rarely observed in Con A-treated lpr/lpr mice, involvement of the Fas-Fas ligand system in this apoptotic process was suggested. These observations suggest that IFN-gamma plays a central role in Con A-hepatitis by activating Fas-induced apoptosis of liver cells.