Fraunhofer Chile Research Foundation

UNLABELLED: Stress induced by the accumulation of unfolded proteins in the endoplasmic reticulum (ER) is observed in many human diseases, including cancers. Cellular adaptation to ER stress is mediated by the unfolded protein response (UPR), which aims at restoring ER homeostasis. The UPR has emerged as a major pathway in remodeling cancer gene expression, thereby either preventing cell transformation or providing an advantage to transformed cells. UPR sensors are highly regulated by the formation of dynamic protein scaffolds, leading to integrated reprogramming of the cells. Herein, we describe the regulatory mechanisms underlying UPR signaling upon cell intrinsic or extrinsic challenges, and how they engage cell transformation programs and/or provide advantages to cancer cells, leading to enhanced aggressiveness or chemoresistance. We discuss the emerging cross-talk between the UPR and related metabolic processes to ensure maintenance of protein homeostasis and its impact on cell transformation and tumor growth. SIGNIFICANCE: ER stress signaling is dysregulated in many forms of cancer and contributes to tumor growth as a survival factor, in addition to modulating other disease-associated processes, including cell migration, cell transformation, and angiogenesis. Evidence for targeting the ER stress signaling pathway as an anticancer strategy is compelling, and novel agents that selectively inhibit the UPR have demonstrated preliminary evidence of preclinical efficacy with an acceptable safety profile.

While mesenchymal stem cells (MSCs)-based therapy appears to be promising, there are concerns regarding possible side effects related to the unwanted suppression of antimicrobial immunity leading to an increased risk of infection. Conversely, recent data show that MSCs exert strong antimicrobial effects through indirect and direct mechanisms, partially mediated by the secretion of antimicrobial peptides and proteins (AMPs). In fact, MSCs have been reported to increase bacterial clearance in preclinical models of sepsis, acute respiratory distress syndrome, and cystic fibrosis-related infections. This article reviews the current evidence regarding the direct antimicrobial effector function of MSCs, focusing mainly on the role of MSCs-derived AMPs. The strategies that might modulate the expression and secretion of these AMPs, leading to enhanced antimicrobial effect, are highlighted. Furthermore, studies evaluating the presence of AMPs in the cargo of extracellular vesicles (EVs) are underlined as perspective opportunities to develop new drug delivery tools. The antimicrobial potential of MSCs-derived EVs can also be heightened through cell conditioning and/or drug loading. Finally, improving the pharmacokinetics and delivery, in addition to deciphering the multi-target drug status of AMPs, should synergistically lead to key advances against infections caused by drug-resistant strains.

Even though exosome-based therapy has been shown to be able to control the progression of different pathologies, the data revealed by pharmacokinetic studies warn of the low residence time of exogenous exosomes in circulation that can hinder the clinical translation of therapeutic exosomes. The macrophages related to the organs of the mononuclear phagocytic system are responsible primarily for the rapid clearance and retention of exosomes, which strongly limits the amount of exosomal particles available to reach the target tissue, accumulate in it and release with high efficiency its therapeutic cargo in acceptor target cells to exert the desired biological effect. Endowing exosomes with surface modifications to evade the immune system is a plausible strategy to contribute to the suppression of exosomal clearance and increase the efficiency of their targeted content delivery. Here, we summarize the current evidence about the mechanisms underlying the recognition and sequestration of therapeutic exosomes by phagocytic cells. Also, we propose different strategies to generate 'invisible' exosomes for the immune system, through the incorporation of different anti-phagocytic molecules on the exosomes’ surface that allow increasing the circulating half-life of therapeutic exosomes with the purpose to increase their bioavailability to reach the target tissue, transfer their therapeutic molecular cargo and improve their efficacy profile. Macrophage-mediated phagocytosis are the main responsible behind the short half-life in circulation of systemically injected exosomes, hindering their therapeutic effect. Exosomes ‘Camouflage Cloak’ strategy using antiphagocytic molecules can contribute to the inhibition of exosomal clearance, hence, increasing the on-target effect. Some candidate molecules that could exert an antiphagocytic role are CD47, CD24, CD44, CD31, β2M, PD-L1, App1, and DHMEQ. Pre- and post-isolation methods for exosome engineering are compatible with the loading of therapeutic cargo and the expression of antiphagocytic surface molecules.

Abstract General circulation models (GCMs) allow the analysis of potential changes in the climate system under different emissions scenarios. However, their spatial resolution is too coarse to produce useful climate information for impact/adaptation assessments. This is especially relevant for regions with complex orography and coastlines, such as in Chile. Downscaling techniques attempt to reduce the gap between global and regional/local scales; for instance, statistical downscaling methods establish empirical relationships between large-scale predictors and local predictands. Here, statistical downscaling was employed to generate climate change projections of daily maximum/minimum temperatures and precipitation in more than 400 locations in Chile using the analog method, which identifies the most similar or analog day based on similarities of large-scale patterns from a pool of historical records. A cross-validation framework was applied using different sets of potential predictors from the NCEP/NCAR reanalysis following the perfect prognosis approach. The best-performing set was used to downscale six different CMIP5 GCMs (forced by three representative concentration pathways, RCPs). As a result, minimum and maximum temperatures are projected to increase in the entire Chilean territory throughout all seasons. Specifically, the minimum (maximum) temperature is projected to increase by more than 2 °C (6 °C) under the RCP8.5 scenario in the austral winter by the end of the twenty-first century. Precipitation changes exhibit a larger spatial variability. By the end of the twenty-first century, a winter precipitation decrease exceeding 40% is projected under RCP8.5 in the central-southern zone, while an increase of over 60% is projected in the northern Andes.

INTRODUCTION: Stem cells isolated from menstrual fluid (MenSCs) exhibit mesenchymal stem cell (MSCs)-like properties including multi-lineage differentiation capacity. Besides, menstrual fluid has important advantages over other sources for the isolation of MSCs, including ease of access and repeated sampling in a noninvasive manner. Such attributes allow the rapid culture of MenSCs in numbers that are sufficient for therapeutical doses, at lower cell passages. METHODS: In this study, we advance the characterization of MenSC populations in comparison to bone marrow derived mesenchymal stem cells (BM-MSCs) with regards to proliferation, lineage differentiation, migration potential, secretion profile and angiogenic properties in vitro and in a matrigel plug assay in mice. We additionally tested their ability to support hematopoietic stem cell (HSC) expansion in vitro. RESULTS: The phenotypic analysis of MenSCs revealed a profile largely similar to the BM-MSCs with the exception of a higher expression of the adhesion molecule CD49a (alpha1-integrin). Furthermore, the fibroblast colony forming units (CFU-F) from MenSCs yielded a 2 to 4 fold higher frequency of progenitors and their in vitro migration capacity was superior to BM-MSCs. In addition, MenSCs evidenced a superior paracrine response to hypoxic conditions as evidenced by the secretion of vascular endothelial growth factor and basic fibroblast growth factor and also improved angiogenic effect of conditioned media on endothelial cells. Furthermore, MenSCs were able to induce angiogenesis in a matrigel plug assay in vivo. Thus, an 8-fold increase in hemoglobin content was observed in implanted plugs containing MenSCs compared to BM-MSCs. Finally, we demonstrated, for the first time, the capacity of MenSCs to support the ex-vivo expansion of HSCs, since higher expansion rates of the CD34+CD133+ population as well as higher numbers of early progenitor (CFU-GEMM) colonies were observed in comparison to the BM source. CONCLUSIONS: We present evidence showing superiority of MenSCs with respect to several functional aspects, in comparison with BM-MSCs. However, the impact of such properties in their use as adult-derived stem cells for regenerative3 medicine remains to be clarified.

Contextual memory formation relies on the induction of new genes in the hippocampus. A polymorphism in the promoter of the transcription factor XBP1 was identified as a risk factor for Alzheimer's disease and bipolar disorders. XBP1 is a major regulator of the unfolded protein response (UPR), mediating adaptation to endoplasmic reticulum (ER) stress. Using a phenotypic screen, we uncovered an unexpected function of XBP1 in cognition and behavior. Mice lacking XBP1 in the nervous system showed specific impairment of contextual memory formation and long-term potentiation (LTP), whereas neuronal XBP1s overexpression improved performance in memory tasks. Gene expression analysis revealed that XBP1 regulates a group of memory-related genes, highlighting brain-derived neurotrophic factor (BDNF), a key component in memory consolidation. Overexpression of BDNF in the hippocampus reversed the XBP1-deficient phenotype. Our study revealed an unanticipated function of XBP1 in cognitive processes that is apparently unrelated to its role in ER stress.

The metabolic profile of Streptomyces sp. strain C34, isolated from the Chilean hyper-arid Atacama Desert soil, is dependent on the culture media used for its growth. The application of an OSMAC approach on this strain using a range of cultivation media resulted in the isolation and identification of three new compounds from the rare class of 22-membered macrolactone polyketides, named chaxalactins A-C (1-3). In addition, the known compounds deferroxamine E (4), hygromycin A (5), and 5″-dihydrohygromycin A (6) were detected. The isolated compounds were characterized by NMR spectroscopy and accurate mass spectrometric analysis. Compounds 1-3 displayed strong activity against Gram-positive but weak activity Gram-negative strains tested.

Estrogens and estrogen-like molecules can modify the biology of several cell types. Estrogen receptors alpha (ERα) and beta (ERβ) belong to the so-called classical family of estrogen receptors, while the G protein-coupled estrogen receptor 1 (GPER-1) represents a non-classical estrogen receptor mainly located in the plasma membrane. As estrogen receptors are ubiquitously distributed, they can modulate cell proliferation, differentiation, and survival in several tissues and organs, including the central nervous system (CNS). Estrogens can exert neuroprotective roles by acting as anti-oxidants, promoting DNA repair, inducing the expression of growth factors, and modulating cerebral blood flow. Additionally, estrogen-dependent signaling pathways are involved in regulating the balance between proliferation and differentiation of neural stem/progenitor cells (NSPCs), thus influencing neurogenic processes. Since several estrogen-based therapies are used nowadays and estrogen-like molecules, including phytoestrogens and xenoestrogens, are omnipresent in our environment, estrogen-dependent changes in cell biology and tissue homeostasis have gained attention in human health and disease. This article provides a comprehensive literature review on the current knowledge of estrogen and estrogen-like molecules and their impact on cell survival and neurodegeneration, as well as their role in NSPCs proliferation/differentiation balance and neurogenesis.

The objective of this review is to outline existing artificial mitochondria transfer techniques and to describe the future steps necessary to develop new therapeutic applications in medicine. Inspired by the symbiotic origin of mitochondria and by the cell's capacity to transfer these organelles to damaged neighbors, many researchers have developed procedures to artificially transfer mitochondria from one cell to another. The techniques currently in use today range from simple coincubations of isolated mitochondria and recipient cells to the use of physical approaches to induce integration. These methods mimic natural mitochondria transfer. In order to use mitochondrial transfer in medicine, we must answer key questions about how to replicate aspects of natural transport processes to improve current artificial transfer methods. Another priority is to determine the optimum quantity and cell/tissue source of the mitochondria in order to induce cell reprogramming or tissue repair, in both in vitro and in vivo applications. Additionally, it is important that the field explores how artificial mitochondria transfer techniques can be used to treat different diseases and how to navigate the ethical issues in such procedures. Without a doubt, mitochondria are more than mere cell power plants, as we continue to discover their potential to be used in medicine.

Streptomyces sp. strain C34, isolated from soil collected in the Chilean hyper-arid Atacama Desert, was cultured on different media, resulting in the isolation and identification of four new ansamycin-type polyketides. The organism was selected for chemical investigation on the basis of a genome-mining PCR-based experiment targeting the gene encoding rifamycin-specific 3-amino-5-hydroxybenzoic acid synthetase (AHBA). The isolated compounds were structurally characterized using NMR and MS techniques and named chaxamycins A-D (1-4). Compounds 1-4 were tested for their antibacterial activity against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 and for their ability to inhibit the intrinsic ATPase activity of the heat shock protein 90 (Hsp90). Chaxamycin D (4), which showed a selective antibacterial activity against S. aureus ATCC 25923, was tested further against a panel of MRSA clinical isolates. In a virtual screening experiment, chaxamycins A-D (1-4) have also been docked into the ATP-binding pocket in the N-terminal domain of the Hsp90, and the observed interactions are discussed.

Polyethylene (PE) is one of the most recalcitrant carbon-based synthetic materials produced and, currently, the most ubiquitous plastic pollutant found in nature. Over time, combined abiotic and biotic processes are thought to eventually breakdown PE. Despite limited evidence of biological PE degradation and speculation that hydrocarbon-degrading bacteria found within the plastisphere is an indication of biodegradation, there is no clear mechanistic understanding of the process. Here, using high-throughput proteomics, we investigated the molecular processes that take place in the hydrocarbon-degrading marine bacterium Alcanivorax sp. 24 when grown in the presence of low density PE (LDPE). As well as efficiently utilising and assimilating the leachate of weathered LDPE, the bacterium was able to reduce the molecular weight distribution (Mw from 122 to 83 kg/mol) and overall mass of pristine LDPE films (0.9 % after 34 days of incubation). Most interestingly, Alcanivorax acquired the isotopic signature of the pristine plastic and induced an extensive array of metabolic pathways for aliphatic compound degradation. Presumably, the primary biodegradation of LDPE by Alcanivorax sp. 24 is possible via the production of extracellular reactive oxygen species as observed both by the material’s surface oxidation and the measurement of superoxide in the culture with LDPE. Our findings confirm that hydrocarbon-biodegrading bacteria within the plastisphere may in fact have a role in degrading PE.

Without a cure, vaccine, or proven long-term immunity against SARS-CoV-2, test-trace-and-isolate (TTI) strategies present a promising tool to contain its spread. For any TTI strategy, however, mitigation is challenged by pre- and asymptomatic transmission, TTI-avoiders, and undetected spreaders, which strongly contribute to "hidden" infection chains. Here, we study a semi-analytical model and identify two tipping points between controlled and uncontrolled spread: (1) the behavior-driven reproduction number [Formula: see text] of the hidden chains becomes too large to be compensated by the TTI capabilities, and (2) the number of new infections exceeds the tracing capacity. Both trigger a self-accelerating spread. We investigate how these tipping points depend on challenges like limited cooperation, missing contacts, and imperfect isolation. Our results suggest that TTI alone is insufficient to contain an otherwise unhindered spread of SARS-CoV-2, implying that complementary measures like social distancing and improved hygiene remain necessary.

A randomized controlled phase I/II clinical trial was designed to evaluate the safety and efficacy of encapsulated human umbilical cord mesenchymal stem cells in a plasma-derived biomaterial for regenerative endodontic procedures (REPs) in mature permanent teeth with apical lesions. The trial included 36 patients with mature incisors, canines, or mandibular premolars showing pulp necrosis and apical periodontitis. Patients were randomly and equally allocated between experimental (REP) or conventional root canal treatment (ENDO) groups. On the first visit, cavity access and mechanical preparation of the root canal were performed. Calcium hydroxide medication was used, and the cavity was sealed. Three weeks later, patients were treated following their assigned protocol of ENDO or REP. Clinical follow-up examinations were performed at 6 and 12 mo. Categorical variables were evaluated by Fisher's exact test. Quantitative variables were compared using the Mann-Whitney test. The evolution over time of the percentage of perfusion units and the dimensions of lesion and cortical compromise were explored. After the 12-mo follow-up, no adverse events were reported, and the patients showed 100% clinical efficacy in both groups. Interestingly, in the REP group, the perfusion unit percentage measured by laser Doppler flowmetry revealed an increase from 60.6% to 78.1% between baseline and 12-mo follow-up. Sensitivity tests revealed an increase of the positive pulp response in the REP group at 12-mo follow-up (from 6% to 56% on the cold test, from 0% to 28% on the hot test, and from 17% to 50% on the electrical test). We present the first clinical safety and efficacy evidence of the endodontic use of allogenic umbilical cord mesenchymal stem cells encapsulated in a plasma-derived biomaterial. The innovative approach, based on biological principles that promote dentin-pulp regeneration, presents a promising alternative for the treatment of periapical pathology (ClinicalTrials.gov NCT03102879).

Recently, exosomes secreted by menstrual mesenchymal stem cells have been identified as inhibitory agents of tumor angiogenesis and modulators of the tumor cell secretome in prostate and breast cancer. However, their direct effect on endothelial cells and paracrine mediators have not yet been investigated. Using a carrier-based cell culture system to test the scalability for exosome production, we showed that different types of endothelial cells present specific kinetics for exosomes internalization. Exosome-treatment of endothelial cells increased cytotoxicity and reduced VEGF secretion and angiogenesis in a dose-dependent manner. Using the hamster buccal pouch carcinoma as a preclinical model for human oral squamous cell carcinoma, we demonstrated a significant antitumor effect of intra-tumoral injection of exosomes associated with a loss of tumor vasculature. These results address up-scaling of exosome production, a relevant issue for their clinical application, and also assess menstrual stem cell exosomes as potential anti-angiogenic agents for the treatment of neoplastic conditions.

Pressurized liquid extraction (PLE) is a clean and environmentally friendly alternative for the recovery of bioactive compounds from fruit by-products. Herein we focused on PLE for the extraction of bioactive compounds from pomegranate peel using a combination of pressurized water and ethanol. The main aim was to determine the optimal PLE conditions, i.e., ethanol percentage and process temperature, to obtain a pomegranate peel extract (PPE) with maximum total phenolic content (TPC), punicalagin content, and antimicrobial activity (AMA). The experimental design was conducted using a central composite design with axial points. Response surface methodology was applied to optimize the response variables using the desirability function. Multiple response optimization indicated a process temperature of 200 °C and ethanol of 77% as optimal conditions. The TPC and the punicalagin content of PPE-PLE obtained under optimal conditions were 164.3 ± 10.7 mg GAE/g DW and 17 ± 3.6 mg/g DW, respectively. Our findings support the efficacy of PLE on TPC recovery but not in punicalagin recovery. The AMA against S. aureus was 14 mm. The efficacy of PPE-PLE in food applications must continue to be studied in order to achieve adequate information on its potential for developing new food additives.

Normal pregnancy is considered as a Th2 type immunological state that favors an immune-tolerance environment in order to prevent fetal rejection. Preeclampsia (PE) has been classically described as a Th1/Th2 imbalance; however, the Th1/Th2 paradigm has proven insufficient to fully explain the functional and molecular changes observed during normal/pathological pregnancies. Recent studies have expanded the Th1/Th2 into a Th1/Th2/Th17 and regulatory T-cells paradigm and where dendritic cells could have a crucial role. Recently, some evidence has emerged supporting the idea that mesenchymal stem cells might be part of the feto-maternal tolerance environment. This review will discuss the involvement of the innate immune system in the establishment of a physiological environment that favors pregnancy and possible alterations related to the development of PE.

The capacity to explore soft tissue structures in detail is important in understanding animal physiology and how this determines features such as movement, behaviour and the impact of trauma on regular function. Here we use advances in micro-computed tomography (micro-CT) technology to explore the brain of an important insect pollinator and model organism, the bumblebee (Bombus terrestris). Here we present a method for accurate imaging and exploration of insect brains that keeps brain tissue free from trauma and in its natural stereo-geometry, and showcase our 3D reconstructions and analyses of 19 individual brains at high resolution. Development of this protocol allows relatively rapid and cost effective brain reconstructions, making it an accessible methodology to the wider scientific community. The protocol describes the necessary steps for sample preparation, tissue staining, micro-CT scanning and 3D reconstruction, followed by a method for image analysis using the freeware SPIERS. These image analysis methods describe how to virtually extract key composite structures from the insect brain, and we demonstrate the application and precision of this method by calculating structural volumes and investigating the allometric relationships between bumblebee brain structures.

With their diverse biological activities, peptides are promising candidates for therapeutic applications, showing antimicrobial, antitumour and hormonal signalling capabilities. Despite their advantages, therapeutic peptides face challenges such as short half-life, limited oral bioavailability and susceptibility to plasma degradation. The rise of computational tools and artificial intelligence (AI) in peptide research has spurred the development of advanced methodologies and databases that are pivotal in the exploration of these complex macromolecules. This perspective delves into integrating AI in peptide development, encompassing classifier methods, predictive systems and the avant-garde design facilitated by deep-generative models like generative adversarial networks and variational autoencoders. There are still challenges, such as the need for processing optimization and careful validation of predictive models. This work outlines traditional strategies for machine learning model construction and training techniques and proposes a comprehensive AI-assisted peptide design and validation pipeline. The evolving landscape of peptide design using AI is emphasized, showcasing the practicality of these methods in expediting the development and discovery of novel peptides within the context of peptide-based drug discovery.

The olive oil industry produces large volumes of wastes, which are also potential sources of bioactive compounds by developing healthy and/or functional foods. Extraction of phenolic compounds from the residues of the olive oil is mainly carried out with solvents. However, there is currently a growing public awareness about the use of organic solvents in food processing, which has pointed out the need for the application of clean technologies such as pressurized liquid extraction (PLE). Therefore, the aim of this research was to optimize the phenolic compound extraction from olive pomace by PLE, establishing the qualitative and quantitative phenolic profile by HPLC-ESI-TOF/MS. The extraction design to recover phenolics from olive pomace demonstrates a great compositional variability of PLE extracts obtained under different experimental conditions. Indeed, quantitative results have pointed out the selectivity of PLE extraction when this technique is applied to the treatment of olive pomace. PLE-optimized conditions showed higher total phenolic compound content than conventional extraction (1659 mg/kg d.w. and 281.7 mg/kg d.w., respectively). Among these phenolics, the quantity of secoiridoids and flavonoids in the optimized PLE extract was three and four times higher than in conventional extracts. Furthermore, optimal PLE conditions allowed to obtain an enriched hydroxytyrosol extract which was not detected in the conventional one.

Lasso peptides are ribosomally synthesized and post-translationally modified peptides (RiPPs) that possess a unique "lariat knot" structural motif. Genome mining-targeted discovery of new natural products from microbes obtained from extreme environments has led to the identification of a gene cluster directing the biosynthesis of a new lasso peptide, designated as chaxapeptin 1, in the genome of Streptomyces leeuwenhoekii strain C58 isolated from the Atacama Desert. Subsequently, 1 was isolated and characterized using high-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance methods. The lasso nature of 1 was confirmed by calculating its nuclear Overhauser effect restraint-based solution structure. Chaxapeptin 1 displayed a significant inhibitory activity in a cell invasion assay with human lung cancer cell line A549.