Unveiling the role of gut-brain axis in regulating neurodegenerative diseases: A comprehensive review.

Emerging evidence have shown the importance of gut microbiota in regulating brain functions. The diverse molecular mechanisms involved in cross-talk between gut and brain provide insight into importance of this communication in maintenance of brain homeostasis. It has also been observed that disturbed gut microbiota contributes to neurological diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis and aging. Recently, gut microbiome-derived exosomes have also been reported to play an essential role in the development and progression of neurodegenerative diseases and could thereby act as a therapeutic target. Further, pharmacological interventions including antibiotics, prebiotics and probiotics can influence gut microbiome-mediated management of neurological diseases. However, extensive research is warranted to better comprehend this interconnection in maintenance of brain homeostasis and its implication in neurological diseases. Thus, the present review is aimed to provide a detailed understanding of gut-brain axis followed by possibilities to target the gut microbiome for improving neurological health.

Bone marrow-derived extracellular vesicles modulate the abundance of infiltrating immune cells in the brain and exert an antiviral effect against the Japanese encephalitis virus.

Mesenchymal stem cells (MSCs) have regenerative capacity and have reported a beneficial effect on the Japanese encephalitis virus (JEV) in an encephalitis model. However, the MSCs do not cross the blood-brain barrier and have other disadvantages limiting their therapeutic utility scope. Recently, there has been a shift in concept from a cell-based to a cell-free approach using MSCs-derived extracellular vesicles (MSC-EVs). The MSC-EVs retain regenerative and immunomodulatory capacity as their parental cells. However, the role of MSC-EVs in limiting JEV pathology remains elusive. In this study, we have used Bone marrow (BM)-derived EV (BM-EVs) and assessed their effect on JEV replication and pathogenesis in primary neuronal stem cells and a murine model. The in vitro and in vivo studies suggested that BM-derived EVs delay JEV-induced symptoms and death in mice, improve the length of survival, accelerate neurogenesis in primary neuronal stem cells, reduce JEV-induced neuronal death, and attenuate viral replication. BM-EVs treatment upregulated interferon-stimulated genes. Flow cytometry analysis revealed a reduction in the frequency of macrophages. At the same time, CD4+ T cells and neutrophils were significantly augmented, accompanied by the alteration of cytokine expression with the administration of BM-EVs, reinforcing the immunomodulatory role of EVs during JEV-induced encephalitis. In conclusion, our study describes the beneficial role of BM-EVs in limiting JEV pathology by attenuating virus replication, enhancing antiviral response, and neurogenesis in primary neuronal stem cells. However, BM-EVs do not seem to protect BBB integrity and alter immune cell infiltration into the treated brain.

Comparative proteomic profiling of Small Extracellular vesicles derived from iPSCs and tissue specific mesenchymal stem cells.

BACKGROUND: Small Extracellular vesicles (EV) are emerging as crucial intercellular messengers that contribute to the physiological processes. EVs contain numerous functional proteins and nucleic acids derived from their parent cells and have different roles depending on their origin. Functionally, EVs transfer these biological materials from the parent cell to the recipient and thus exhibits a novel therapeutic platform for delivering therapeutics molecules to the target tissue. In this regard, EVs derived from stem cells such as Mesenchymal Stem Cells and iPSCs have demonstrated a higher ability to benefit regenerative medicine. Even though these stem cells share some common properties, due to the differences in their origin (cell sources, the hierarchy of potency, etc) the EVs cargo profiling and functionality may vary. METHOD: We used iTRAQ-based proteomic analysis to conduct a comprehensive and quantitative evaluation of EVs derived from iPSCs and various tissue-specific MSCs in this study. Additionally, the data was analyzed using a variety of bioinformatic tools, including ProteinPilot for peptide and protein identification and quantification; Funrich, GO, Reactome, and KEGG (Kyoto Encyclopedia of Genes and Genomes) for pathway enrichment; the STRING database, and the inBio Discover tool for identifying known and predicted Protein-Protein networks. RESULTS: Bioinformatics analysis revealed 223 differentially expressed proteins in these EVs; however, Wharton's jelly MSC-EV contained more exclusive proteins with higher protein expression levels. Additionally, 113 proteins were abundant in MSC-EVs, while others were shared between MSC-EVs and iPSC-EVs. Further, based on an in-depth examination of the proteins, their associated pathways, and their interactions with other proteins, it was determined that these proteins are involved in bone regeneration (9.3%), wound healing (4.4%), immune regulation (8.9%), cardiac regeneration (6.6%), neuro regeneration (8.9%), and hepatic regeneration (3.5%). CONCLUSION: Overall, the results of our proteomic analysis indicate that EVs derived from MSCs have a more robust profile of proteins with higher expression levels than iPSCs. This is a significant finding, as it demonstrates the critical therapeutic role of EVs in a variety of diseases, as demonstrated by enrichment analysis, their versatility, and broad application potential.

Targeting mitochondria in the regulation of neurodegenerative diseases: A comprehensive review.

Mitochondria are one of the essential cellular organelles. Apart from being considered as the powerhouse of the cell, mitochondria have been widely known to regulate redox reaction, inflammation, cell survival, cell death, metabolism, etc., and are implicated in the progression of numerous disease conditions including neurodegenerative diseases. Since brain is an energy-demanding organ, mitochondria and their functions are important for maintaining normal brain homeostasis. Alterations in mitochondrial gene expression, mutations, and epigenetic modification contribute to inflammation and neurodegeneration. Dysregulation of reactive oxygen species production by mitochondria and aggregation of proteins in neurons leads to alteration in mitochondria functions which further causes neuronal death and progression of neurodegeneration. Pharmacological studies have prioritized mitochondria as a possible drug target in the regulation of neurodegenerative diseases. Therefore, the present review article has been intended to provide a comprehensive understanding of mitochondrial role in the development and progression of neurodegenerative diseases mainly Alzheimer's, Parkinson's, multiple sclerosis, and amyotrophic lateral sclerosis followed by possible intervention and future treatment strategies to combat mitochondrial-mediated neurodegeneration.

Do Carbon Nanotubes and Asbestos Fibers Exhibit Common Toxicity Mechanisms?

During the last two decades several nanoscale materials were engineered for industrial and medical applications. Among them carbon nanotubes (CNTs) are the most exploited nanomaterials with global production of around 1000 tons/year. Besides several commercial benefits of CNTs, the fiber-like structures and their bio-persistency in lung tissues raise serious concerns about the possible adverse human health effects resembling those of asbestos fibers. In this review, we present a comparative analysis between CNTs and asbestos fibers using the following four parameters: (1) fibrous needle-like shape, (2) bio-persistent nature, (3) high surface to volume ratio and (4) capacity to adsorb toxicants/pollutants on the surface. We also compare mechanisms underlying the toxicity caused by certain diameters and lengths of CNTs and asbestos fibers using downstream pathways associated with altered gene expression data from both asbestos and CNT exposure. Our results suggest that indeed certain types of CNTs are emulating asbestos fiber as far as associated toxicity is concerned.

Hypoxia preconditioning elicit differential response in tissue-specific MSCs via immunomodulation and exosomal secretion.

Mesenchymal stromal cells (MSCs) are emerging as an ideal candidate for regenerative medicine. It is known that the culture conditions impact the cellular properties of MSCs and their therapeutic behavior. Moreover, maintenance of MSCs in low oxygen tension for a short duration has shown to be beneficial for MSCs as it is similar to that of their physiological niche. However, the precise mechanism through which hypoxia pre-conditioning affects MSCs is not clear yet. Thus, in this study, we have investigated the effect of hypoxia exposure (1% O2) on tissue-specific MSCs over a period of time under serum-free culture conditions and evaluated the changes in expression of immuno-modulatory molecules and exosome biogenesis and secretion markers. It was observed that all MSCs responded differentially towards hypoxia exposure as indicated by the expression of HIF-1α. Moreover, this short-term exposure did not induce any changes in MSCs cellular morphology, proliferation rate, and surface marker profiling. In addition, we observed an enhancement in the expression of immunomodulatory factors (HLA-G, PGE-2, and IDO) after hypoxia exposure of 12 to 24 h in all tissue-specific MSCs. Interestingly, we have also observed the upregulation in exosome secretion that was further corelated to the upregulation of expression of exosome biogenesis and secretion markers (ALIX, TSG101, RAB27a, RAB27b). Though there was a differential response of MSCs where WJ-MSCs and BM-MSCs showed upregulation of these markers at 6-12 h of hypoxia pre-conditioning, while AD-MSCs showed similar changes beyond 24 h of hypoxia exposure.

Comparative Evaluation of Anti-Fibrotic Effect of Tissue Specific Mesenchymal Stem Cells Derived Extracellular Vesicles for the Amelioration of CCl4 Induced Chronic Liver Injury.

Mesenchymal Stem Cells (MSCs) derived Extracellular Vesicles (EVs) have emerged as an effective candidate for amelioration of liver fibrosis. However, the effect and the mechanisms of MSC-EVs in liver repair remains elusive. In this study, we have evaluated the differential regenerative efficacy of EVs derived from two different human tissue-specific MSCs (Adipose tissue; AD-MSC and Wharton's Jelly; WJ-MSC), in a murine model of chronic liver fibrosis. Mouse model of chronic liver injury was induced by carbon tetrachloride (CCl4) injection, followed by administration of EVs via the tail vein. Both quantitative and qualitative assessment was done to evaluate the hepatic regenerative potential of tissue specific MSC-extracellular vesicles. EVs, regardless of their MSC source, were found to be effective in alleviating chronic liver fibrosis, as demonstrated by macroscopic alterations in the liver. According to the findings of the comprehensive study, there were subtle variations in the tissue specific MSCs-EVs mediated approaches. A greater anti-fibrotic impact was demonstrated by AD-MSC derived EVs through extracellular matrix alteration and hepatocyte proliferation. WJ-MSC EVs, on the other hand, have an anti-inflammatory effect, as evidenced by alterations in the expression of pro- and anti-inflammatory cytokines. Furthermore, cargo profiling of these EVs revealed differences in the miRNA and protein expression, as well as the pathways that they were associated. Comparative overview of regression of fibrosis using tissue specific MSC derived EVs (credits BioRender.com ).

Transcriptional and epigenetic regulation of microglia in maintenance of brain homeostasis and neurodegeneration.

The emerging role of microglia in brain homeostasis, neurodegeneration, and neurodevelopmental disorders has attracted considerable interest. In addition, recent developments in microglial functions and associated pathways have shed new light on their fundamental role in the immunological surveillance of the brain. Understanding the interconnections between microglia, neurons, and non-neuronal cells have opened up additional avenues for research in this evolving field. Furthermore, the study of microglia at the transcriptional and epigenetic levels has enhanced our knowledge of these native brain immune cells. Moreover, exploring various facets of microglia biology will facilitate the early detection, treatment, and management of neurological disorders. Consequently, the present review aimed to provide comprehensive insight on microglia biology and its influence on brain development, homeostasis, management of disease, and highlights microglia as potential therapeutic targets in neurodegenerative and neurodevelopmental diseases.

Establishment of a murine model of acute-on-chronic liver failure with multi-organ dysfunction.

BACKGROUND AND AIMS: Acute-on-chronic liver failure (ACLF) is a distinct clinical entity with high probability of organ failure and mortality. Since patients generally present late, experimental models are needed to understand the pathophysiology and natural course of the disease. METHODOLOGY: To reproduce the syndrome of ACLF, chronic liver disease was induced in C57BL6 mice (6-8 weeks; approximately 20-24 g weight) by intraperitoneal administration of carbon tetrachloride (CCl4) for 10 weeks followed by an acute injury with acetaminophen (APAP) and lipopolysaccharide (LPS). Blood, ascitic fluid, and organs were collected to study cell death, regeneration, and fibrosis. RESULTS: At 24 h post-APAP/LPS infusion, the liver tissue showed increased hepatocyte ballooning and endothelial cell TUNEL positivity. This was followed by progressive hepatocyte necrosis from perivascular region at day 7 to lobular region by day 11. ACLF (day 7 and day 11) animals showed increase in bilirubin (p < 0.05), prothrombin time (p < 0.0001), blood ammonia (p < 0.001), and portal pressure post-acute hepatocellular injury similar to human ACLF. Ascites was noticed by day 11 with median serum-ascites albumin gradient of 1.2 (1.1-1.3) g/dL. In comparison to cirrhosis, ACLF group (day 7 and day 11) showed significant decrease in Sirius red (p ≤ 0.0001), collagen1 (p < 0.0001), and a-SMA proportionate area (p < 0.0001) with loss of hepatocytes regeneration (p < 0.005). At day 11, ACLF animals also showed significant increase in serum creatinine (p < 0.05) and acute tubular necrosis suggestive of organ failure, compared to cirrhotic animals. CONCLUSION: The CCL4/APAP/LPS (CALPS) model of ACLF mimics the clinical, biochemical, and histological features of ACLF with demonstrable progressive hepatocellular necrosis, liver failure, impaired regeneration, development of portal hypertension, and organ dysfunction in an animal with chronic liver disease.

Mesenchymal Stem Cell-Derived Exosomes as an Emerging Paradigm for Regenerative Therapy and Nano-Medicine: A Comprehensive Review.

Mesenchymal Stem Cells are potent therapeutic candidates in the field of regenerative medicine, owing to their immunomodulatory and differentiation potential. However, several complications come with their translational application like viability, duration, and degree of expansion, long-term storage, and high maintenance cost. Therefore, drawbacks of cell-based therapy can be overcome by a novel therapeutic modality emerging in translational research and application, i.e., exosomes. These small vesicles derived from mesenchymal stem cells are emerging as new avenues in the field of nano-medicine. These nano-vesicles have caught the attention of researchers with their potency as regenerative medicine both in nanotherapeutics and drug delivery systems. In this review, we discuss the current knowledge in the biology and handling of exosomes, with their limitations and future applications. Additionally, we highlight current perspectives that primarily focus on their effect on various diseases and their potential as a drug delivery vehicle.

Human Acquired Aplastic Anemia Patients' Bone-Marrow-Derived Mesenchymal Stem Cells Are Not Influenced by Hematopoietic Compartment and Maintain Stemness and Immune Properties.

METHODS: In the current study, we investigated the morphological differences, proliferation capacity, population doubling time (PDT), surface marker profiling, trilineage differentiation potential, and immunosuppressive ability of BM Mesenchymal Stem Cells (BM-MSCs) from untreated aAA patients and in the same number of age- and gender-matched controls. RESULTS: We observed similar morphology, proliferation capacity, phenotype, trilineage differentiation potential, and immunomodulatory properties of BM-MSCs in aAA patients and control subjects. CONCLUSION: Our results confirm that the basic and immunosuppressive properties of BM-MSCs from aAA patients do not differ from normal BM-MSCs. Our data suggest that BM-MSCs from aAA patients might not be involved in disease pathogenesis. However, owing to a smaller number of samples, it is not conclusive, and future studies with more exhaustive investigation at transcriptome level are warranted.

MicroRNA-Enriched Exosomes from Different Sources of Mesenchymal Stem Cells Can Differentially Modulate Functions of Immune Cells and Neurogenesis.

Adult Mesenchymal stem cells-derived exosomes carry several biologically active molecules that play prominent roles in controlling disease manifestations. The content of these exosomes, their functions, and effect on the immune cells may differ depending on their tissue sources. Therefore, in this study, we purified the exosomes from three different sources and, using the RNA-Seq approach, highly abundant microRNAs were identified and compared between exosomes and parental cells. The effects of exosomes on different immune cells were studied in vitro by incubating exosomes with PBMC and neutrophils and assessing their functions. The expression levels of several miRNAs varied within the different MSCs and exosomes. Additionally, the expression profile of most of the miRNAs was not similar to that of their respective sources. Exosomes isolated from different sources had different abilities to induce the process of neurogenesis and angiogenesis. Moreover, these exosomes demonstrated their varying effect on PBMC proliferation, neutrophil survival, and NET formation, highlighting their versatility and broad interaction with immune cells. The knowledge gained from this study will improve our understanding of the miRNA landscape of exosomes from hMSCs and provide a resource for further improving our understanding of exosome cargo and their interaction with immune cells.

Mesenchymal Stem Cell Derived Exosomes: a Nano Platform for Therapeutics and Drug Delivery in Combating COVID-19.

The recent pandemic situation transpired due to coronavirus novel strain SARS-CoV-2 has become a global concern. This human coronavirus (HCov-19) has put the world on high alert as the numbers of confirmed cases are continuously increasing. The world is now fighting against this deadly virus and is leaving no stone unturned to find effective treatments through testing of various available drugs, including those effective against flu, malaria, etc. With an urgent need for the development of potential strategies, two recent studies from China using Mesenchymal Stem Cells (MSCs) to treat COVID-19 pneumonia have shed some light on a potential cure for the COVID-19 infected patients. However, MSCs, despite being used in various other clinical trials have always been questioned for their tendency to aggregate or form clumps in the injured or disease microenvironment. It has also been reported in various studies that exosomes secreted by these MSCs, contribute towards the cell's biological and therapeutic efficacy. There have been reports evaluating the safety and feasibility of these exosomes in various lung diseases, thereby proposing them as a cell-free therapeutic agent. Also, attractive features like cell targeting, low-immunogenicity, safety, and high biocompatibility distinguish these exosomes from other synthetic nano-vesicles and thus potentiate their role as a drug delivery nano-platform. Building upon these observations, herein, efforts are made to give an overview of stem cell-derived exosomes as an appealing therapeutic agent and drug delivery nano-carrier. In this review, we briefly recapitulate the recent evidence and developments in understanding exosomes as a promising candidate for novel nano-intervention in the current pandemic scenario. Furthermore, this review will highlight and discuss mechanistic role of exosomes to combat severe lung pathological conditions. We have also attempted to dwell into the nano-formulation of exosomes for its better applicability, storage, and stability thereby conferring them as off the shelf therapeutic.

WITHDRAWN: The Atlas of Inflammation Resolution (AIR).

The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.mam.2020.100894. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

The Atlas of Inflammation Resolution (AIR).

Acute inflammation is a protective reaction by the immune system in response to invading pathogens or tissue damage. Ideally, the response should be localized, self-limited, and returning to homeostasis. If not resolved, acute inflammation can result in organ pathologies leading to chronic inflammatory phenotypes. Acute inflammation and inflammation resolution are complex coordinated processes, involving a number of cell types, interacting in space and time. The biomolecular complexity and the fact that several biomedical fields are involved, make a multi- and interdisciplinary approach necessary. The Atlas of Inflammation Resolution (AIR) is a web-based resource capturing an essential part of the state-of-the-art in acute inflammation and inflammation resolution research. The AIR provides an interface for users to search thousands of interactions, arranged in inter-connected multi-layers of process diagrams, covering a wide range of clinically relevant phenotypes. By mapping experimental data onto the AIR, it can be used to elucidate drug action as well as molecular mechanisms underlying different disease phenotypes. For the visualization and exploration of information, the AIR uses the Minerva platform, which is a well-established tool for the presentation of disease maps. The molecular details of the AIR are encoded using international standards. The AIR was created as a freely accessible resource, supporting research and education in the fields of acute inflammation and inflammation resolution. The AIR connects research communities, facilitates clinical decision making, and supports research scientists in the formulation and validation of hypotheses. The AIR is accessible through https://air.bio.informatik.uni-rostock.de.

Efficient Labeling of Human Mesenchymal Stem Cells Using Iron Oxide Nanoparticles.

Stem cells have been used in multiple clinical trials. Tracking these transplanted cells in vivo will provide real-time information on the fate of these cells. Iron oxide labeling is one such uncomplicated noninvasive labeling method. These transformed nanocrystals can be used for varied applications including stem-cell tracking, magnetic resonance imaging, and theranostics. Here we elucidate the protocol for iron oxide nanoparticles synthesis (IONPS) and labeling of mesenchymal stem cells which can be used for imaging and tracking cells to understand their fate in in vivo studies.

Adipose tissue derived mesenchymal stem cells are better respondents to TGFß1 for in vitro generation of cardiomyocyte-like cells.

Mesenchymal stem cells (MSCs) are multipotent cells which hold immense potential in translational research as a novel treatment modality. In recent years, MSCs isolated from various tissues have been used in several clinical trials for the treatment of cardiac injury caused by permanent myocardial loss. However, a better MSCs source and an optimum inducer for in vitro cardiac differentiation are still far reaching and unexplored. The aim of the study was to compare the ability and efficiency of differentiation of MSCs isolated from bone marrow (BM-MSCs) and adipose tissue (ADSC) into cardiomyocyte-like cells to aid translational research. To fulfill this aim, freshly isolated BM-MSCs and ADSCs were differentiated into cardiomyocytes using 5-Azacytidine (6 µM) and TGF-ß1 (25 ng/ml). These two differentiation protocols were compared on the basis of morphological, transcriptional, translational and functionality analysis. Both tissue specific MSCs, ADSCs and BM-MSCs, have similar surface marker profile and population doubling time. In both the treatment regimes, BM-MSCs and ADSCs showed morphological changes like flattening of cells and myotube formation in concurrence with structure and multinucleation, with early sign of differentiation in ADSCs. Further, the expression of cardiac specific markers including myosin light chain-2v (Mlc-2v), cardiac troponin I (cTnI), and sarco/endoplasmic reticulum Ca2+-ATPase (SerCa2) were higher in AD-TGFß1 group, both at transcriptional and translational level. During functionality analysis by KCl stimulation, increased intracellular calcium fluorescence was observed in AD- TGFß1 group as compared to others. Thus, ADSCs proved to be a better choice for stem cell therapy in cardiovascular diseases when induced with TGF-ß1.

An improvised one-step sucrose cushion ultracentrifugation method for exosome isolation from culture supernatants of mesenchymal stem cells.

BACKGROUND: Exosomes are nanovesicles (30-120 nm) of endosomal origin. These exosomes contain various functional proteins and RNAs that could be used for therapeutic purposes. Currently, having a standard method for exosome isolation retaining its biological properties with increased yield and purity is a major challenge. The most commonly used method is differential ultracentrifugation but it has its own disadvantages, which include high time consumption, low yield due to disruption of exosome integrity, and high protein contaminants. In this study, we have identified an improved method addressing these problems for exosome isolation using ultracentrifugation since it is cost-effective and used worldwide. METHOD: We have compared differential ultracentrifugation with the modified method called one-step sucrose cushion ultracentrifugation for exosome isolation. The conditioned serum-free media from human mesenchymal stem cells cultured for 48 h was collected for exosome isolation. The cellular debris was removed by centrifugation at 300g for 10 min, followed by centrifugation at 10,000g for 30 min to remove microvesicles. Equal volumes of pre-processed conditioned media were used for exosome isolation by direct ultracentrifugation and one-step sucrose cushion ultracentrifugation. The exosomes isolated using these methods were characterized for their size, morphology, concentration, and surface marker protein expression. RESULT: It was observed that the recovery of exosomes with cup-shaped morphology from one-step sucrose cushion ultracentrifugation was comparatively high as estimated by nanoparticle tracking analysis and electron microscopy. These results were confirmed by Western blotting and flow cytometry. CONCLUSION: We conclude that this one-step sucrose cushion ultracentrifugation method provides an effective and reproducible potential standard method which could be used for various starting materials for isolating exosomes. We believe that this method will have a wide application in the field of extracellular vesicle research where exosome isolation with high yield and purity is an imperative step. Schematic representation of comparison of UC and SUC exosome isolation methods for tissue-specific human mesenchymal stem cells. The SUC isolation method yields a greater number of cup-shaped exosomes with a relatively homogenous population for mass-scale production of exosomes for downstream analysis. ABBREVIATIONS: SUC One-step sucrose cushion ultracentrifugation, UC Direct ultracentrifugation.