VX-765 enhances autophagy of human umbilical cord mesenchymal stem cells against stroke-induced apoptosis and inflammatory responses via AMPK/mTOR signaling pathway

Targeting pyroptosis to treat ischemic stroke: From molecular pathways to treatment strategy

Ischemic stroke is the primary reason for human disability and death, but the available treatment options are limited. Hence, it is imperative to explore novel and efficient therapies. In recent years, pyroptosis (a pro-inflammatory cell death characterized by inflammation) has emerged as an important pathological mechanism in ischemic stroke that can cause cell death through plasma membrane rupture and release of inflammatory cytokines. Pyroptosis is closely associated with inflammation, which exacerbates the inflammatory response in ischemic stroke. The level of inflammasomes, GSDMD, Caspases, and inflammatory factors is increased after ischemic stroke, exacerbating brain injury by mediating pyroptosis. Hence, inhibition of pyroptosis can be a therapeutic strategy for ischemic stroke. In this review, we have summarized the relationship between pyroptosis and ischemic stroke, as well as a series of treatments to attenuate pyroptosis, intending to provide insights for new therapeutic targets on ischemic stroke.

Mesenchymal stem cells and their extracellular vesicles as emerging therapeutic tools in the treatment of ischemic stroke

Ischemic stroke (IS) is a neurological condition characterized by severe long-term consequences and an unfavorable prognosis for numerous patients. Despite advancements in stroke treatment, existing therapeutic approaches possess certain limitations. However, accumulating evidence suggests that mesenchymal stem/stromal cells (MSCs) hold promise as a potential therapy for various neurological disorders, including IS, owing to their advantageous properties, such as immunomodulation and tissue regeneration. Additionally, MSCs primarily exert their therapeutic effects through the release of extracellular vesicles (EVs), highlighting the significance of their paracrine activities. These EVs are small double-layered phospholipid membrane vesicles, carrying a diverse cargo of proteins, lipids, and miRNAs that enable effective cell-to-cell communication. Notably, EVs have emerged as attractive substitutes for stem cell therapy due to their reduced immunogenicity, lower tumorigenic potential, and ease of administration and handling. Hence, this review summarizes the current preclinical and clinical studies performed to investigate the safety and therapeutic potential of MSCs and their EVs derived from different sources, including bone marrow, adipose tissue, umbilical cord blood, and Wharton's jelly in IS.

Lycium barbarum polysaccharide inhibits ischemia-induced autophagy by promoting the biogenesis of neural stem cells-derived extracellular vesicles to enhance the delivery of miR-133a-3p

BACKGROUND

Neural stem cell-derived extracellular vesicles (NSC-EVs) mediated endogenous neurogenesis determines a crucial impact on spontaneous recovery after stroke. Here, we checked the influence of Lycium barbarum polysaccharide (LBP) on the biogenesis of NSC-EVs and then focused on studying mechanisms of LBP in ameliorating ischemic stroke outcome.

METHODS

LBP was prepared to precondition NSCs and isolate EVs. MCAO models and primary NSCs were administrated to evaluate the therapeutic effect. RT-PCR, western blot, flow cytometry, and immunofluorescence techniques were performed to explore the mechanism.

RESULTS

LBP pretreatment increased the production of NSC-EVs and improved the neuroprotective and recovery effects of NSC-EV in ischemic stroke mice. LBP-pretreated NSC-EV in a dose-dependent manner substantially reduced neuronal death compared with NSC-EV. Screening of the signaling cascade involved in the interaction between NSC-EV and neurons revealed that AMPK/mTOR signaling pathway inhibited autophagic activity in neurons receiving either treatment paradigm. NSC-EVs but not EVs collected from NSCs pretreated with the anti-miR-133a-3p oligonucleotide reduced cell death, whereas the anti-oligonucleotide promoted autophagy activity and cell death by modulating AMPK/mTOR signaling in OGD-induced primary neurons.

CONCLUSION

LBP activated AMPK/mTOR signaling pathway by increasing the enrichment and transfer of miR-133a-3p in NSC-EVs to inhibit stroke-induced autophagy activity.

NLRP3 inflammasome activation after ischemic stroke

Cerebral ischemia is a pathological condition resulting from the cessation or reduction of blood supply to the cerebral arteries. Neurological deficits that are clinically relevant can arise as a result of brain damage. The etiology of stroke is multifaceted and intricate, with the inflammatory response being a crucial component that warrants significant attention. Following a cerebrovascular accident, the levels of interleukin-1 beta and interleukin-18 within the central nervous system escalate due to the activation of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasome. The inflammation is aggravated by the subsequent occurrence of pyroptosis. The mechanisms that activate the NLRP3 inflammasome pyroptosis signaling pathway axis are described in this article. In addition, we go over how pyroptosis interacts with other processes for regulated cell death. In addition, specific NLRP3 inflammasome pathway inhibitors are identified, which offer new approaches to preventing ischemic brain injury.

A cross-talk between sestrins, chronic inflammation and cellular senescence governs the development of age-associated sarcopenia and obesity

The rapid increase in both the lifespan and proportion of older adults is accompanied by the unprecedented rise in age-associated chronic diseases, including sarcopenia and obesity. Aging is also manifested by increased susceptibility to multiple endogenous and exogenous stresses enabling such chronic conditions to develop. Among the main physiological regulators of cellular adaption to various stress stimuli, such as DNA damage, hypoxia, and oxidative stress, are sestrins (Sesns), a family of three evolutionarily conserved proteins, Sesn1, 2, and 3. Age-associated sarcopenia and obesity are characterized by two key processes: (i) accumulation of senescent cells in the skeletal muscle and adipose tissue and (ii) creation of a systemic, chronic, low-grade inflammation (SCLGI). Presumably, failed SCLGI resolution governs the development of these chronic conditions. Noteworthy, Sesns activate senolytics, which are agents that selectively eliminate senescent cells, as well as specialized pro-resolving mediators, which are factors that physiologically provide inflammation resolution. Sesns reveal clear beneficial effects in pre-clinical models of sarcopenia and obesity. Based on these observations, we propose a novel treatment strategy for age-associated sarcopenia and obesity, complementary to the conventional therapeutic modalities: Sesn activation, SCLGI resolution, and senescent cell elimination.

Contemplating IL-6, a double-edged sword cytokine: Which side to use for stroke pathology?

Interleukin (IL)-6 is a unique cytokine due to its dual signaling, with one pathway being pro-inflammatory (trans) and the other homeostatic (classical). Both of these pathways have been implicated in neuroinflammation following stroke, with initial inflammatory mechanisms being protective and later anti-inflammatory signaling promoting ischemic tissue recovery. IL-6 plays a major role in stroke pathology. However, given these distinctive IL-6 signaling consequences, IL-6 is a difficult cytokine to target for stroke therapies. Recent research suggests that the ratio between the pro-inflammatory binary IL6:sIL6R complex and the inactive ternary IL6:sIL6R:sgp130 complex may be a novel way to measure IL-6 signaling at different time points following ischemic injury. This ratio may approximate functional consequences on individualized stroke therapies, allowing clinicians to determine whether IL-6 agonists or antagonists should be used at specific time points.

Probing Interleukin-6 in Stroke Pathology and Neural Stem Cell Transplantation

Stem cell transplantation is historically understood as a powerful preclinical therapeutic following stroke models. Current clinical strategies including clot busting/retrieval are limited by their time windows (tissue plasminogen activator: 3-4 h) and inevitable reperfusion injuries. However, 24+ h post-stroke, stem cells reduce infarction size, improve neurobehavioral performance, and reduce inflammatory agents including interleukins. Typically, interleukin-6 (IL-6) is regarded as proinflammatory, and thus, preclinical studies often discuss it as beneficial for neurological recuperation when stem cells reduce IL-6's expression. However, some studies have also demonstrated neurological benefit with upregulation of IL-6 or preconditioning of stem cells with IL-6. This review specifically focuses on stem cells and IL-6, and their occasionally disparate, occasionally synergistic roles in the setting of ischemic cerebrovascular insults.

Lipopolysaccharide Promotes the Proliferation and Differentiation of Goose Embryonic Myoblasts by Promoting Cytokine Expression and Appropriate Apoptosis Processes

Lipopolysaccharide (LPS) can trigger a series of immune reactions, leading to the occurrence of disease and a decrease in the growth performance of geese. However, the mechanisms of LPS in geese muscle development have not been reported. This study aimed to investigate the effects and mechanisms of LPS on proliferation and differentiation of goose embryonic myoblasts. Embelin and belnacasan combined with LPS were used to explore these effects. Our results demonstrated that LPS significantly induced inflammatory cytokine production in both proliferation and differentiation stages. LPS and embelin treatment significantly improved the proliferation ability (p < 0.05), while LPS reduced the differentiation ability of goose embryonic myoblasts. By adding embelin, the differentiation ability of myoblasts was enhanced, while by adding belnacasan, LPS treatment led to a lower differentiation ability. Combined with the correlation of the expression levels of myogenic, cell cycle, and inflammatory-related genes and proteins, it is speculated that one of the reason for the decrease of differentiation ability of goose embryo myoblasts induced by LPS is the increase of the expression levels of pro-inflammatory factors. Moreover, LPS, embelin and belnacasan, and LPS treatments could significantly increase the apoptosis rate of goose embryonic myoblasts. Taken together, these findings suggest that LPS promotes the proliferation and differentiation of goose embryonic myoblasts by promoting cytokine expression and appropriate apoptosis processes. These findings lay a foundation for the study of the mechanisms of LPS in goose muscle development.

Melatonin attenuates chronic stress-induced hippocampal inflammatory response and apoptosis by inhibiting ADAM17/TNF-α axis

Melatonin, as a dietary supplement, has a potent neuroprotective effect and exerts a certain antidepressant effect. This study explored the molecular mechanisms and targets of melatonin on chronic stress-induced hippocampal damage from the perspective of inhibiting inflammatory cytokines release. Our results indicated that melatonin alleviated chronic restraint stress (CRS)-induced inflammatory response and apoptosis, thus improving hippocampal structural damage and subsequent depression-like behaviors in rats. The radar map displayed that the change of TNF-α content was the most significant. Meanwhile, correlation analysis showed that TNF-α content was highly positively correlated with apoptosis. Molecular autodocking studies suggested that TNF-α converting enzyme ADAM17 as a potential target has a priority in docking with melatonin. Molecular mechanism studies indicated that melatonin inhibited CRS-induced activation of the ADAM17/TNF-α axis and its downstream proteins p38 and p53 phosphorylation in the hippocampus. Analogously, Both ADAM17 inhibitor TMI-1 and TNF-α inhibitor thalidomide relieved the effects of CRS on ADAM17/TNF-α axis and its downstream proteins phosphorylation, hippocampal apoptosis, hippocampal inflammatory response, and depression-like behaviors in rats. Altogether, these findings reveal that melatonin relieves CRS-induced inflammatory response and apoptosis, and subsequent depression-like behaviors by inhibiting ADAM17/TNF-α axis.

Glutamate excitotoxicity: Potential therapeutic target for ischemic stroke

Glutamate-mediated excitotoxicity is an important mechanism leading to post ischemic stroke damage. After acute stroke, the sudden reduction in cerebral blood flow is most initially followed by ion transport protein dysfunction and disruption of ion homeostasis, which in turn leads to impaired glutamate release, reuptake, and excessive N-methyl-D-aspartate receptor (NMDAR) activation, promoting neuronal death. Despite extensive evidence from preclinical studies suggesting that excessive NMDAR stimulation during ischemic stroke is a central step in post-stroke damage, NMDAR blockers have failed to translate into clinical stroke treatment. Current treatment options for stroke are very limited, and there is therefore a great need to develop new targets for neuroprotective therapeutic agents in ischemic stroke to extend the therapeutic time window. In this review, we highlight recent findings on glutamate release, reuptake mechanisms, NMDAR and its downstream cellular signaling pathways in post-ischemic stroke damage, and review the pathological changes in each link to help develop viable new therapeutic targets. We then also summarize potential neuroprotective drugs and therapeutic approaches for these new targets in the treatment of ischemic stroke.

Erythropoietin promotes the differentiation of fetal neural stem cells into glial cells via the erythropoietin receptor-β common receptor/Syne-1/H3K9me3 pathway

Aims

To investigate the effect of erythropoietin (EPO) on the differentiation of neural stem cells (NSCs)/neural progenitors (NPs) in the treatment of hypoxic–ischemic injury and its potential mechanisms.

Methods

Fetal NSCs/NPs were treated with EPO after oxygen and glucose deprivation/reoxygenation (OGD/R). Cell viability, proliferation, and differentiation of NSCs/NPs were detected by CellTiter‐Glo, Edu assay, flow cytometry, and quantitative real‐time PCR (qPCR). Immunofluorescence staining, co‐immunoprecipitation (Co‐IP), and western blotting were used to test the existence of EPO receptor/β common receptor (EPOR/βCR) heterodimer on NSCs/NPs and the possible pathway.

Results

EPO treatment at different time points increased cell viability without affecting proliferation. EPO treatment immediately after OGD/R promoted oligodendrocyte and astrocyte differentiation, while decreasing neuronal differentiation of NSCs/NPs. EPOR/βCR heterodimer existed on the cell surface of the fetal cortical NSCs/NPs, EPO treatment significantly increased the mRNA expression of βCR and elevated the correlation between EPOR and βCR levels. In addition, mass spectrometry analysis identified Syne‐1 as a downstream signaling molecule of the EPOR/βCR heterodimer. Immunofluorescence staining and western blotting indicated that the βCR/Syne‐1/H3K9me3 pathway was possibly involved in the differentiation of fetal neural stem cells into the glial cell effect of EPO.

Conclusion

EPO treatment immediately after OGD/R could not facilitate fetal NSCs/NPs neurogenesis but promoted the formation of the EPOR/βCR heterodimer on fetal NSCs/NPs, which mediates its function in glial differentiation.

MiR-153 downregulation alleviates PTSD-like behaviors and reduces cell apoptosis by upregulating the Sigma-1 receptor in the hippocampus of rats exposed to single-prolonged stress

Posttraumatic stress disorder (PTSD) is a psychiatric disorder that may lead to a series of changes in the central nervous system, including impaired synaptic plasticity, neuronal dendritic spine loss, enhanced apoptosis and increased inflammation. However, the specific mechanism of PTSD has not been studied clearly. In the present study, we found that the level of miR-153-3p in the hippocampus of rats exposed tosingle-prolonged stresss (SPS) was upregulated, but its downstream target σ-1R showed a significant decrease. The downregulation of miR-153 could alleviate the PTSD-like behaviors in the rats exposed to SPS, and this effect might be related to the upregulation of σ-1R and PSD95. Furthermore, anti-miR-153 could also increase the dendritic spine density and reduce cell apoptosis in the hippocampus of SPS rats. In addition, we showed that the mTOR signaling pathway might be involved in the regulation of σ-1R in the hippocampus of rats exposed to SPS. The results of this study indicated that miR-153 might alleviate PTSD-like behaviors by regulating cell morphology and reducing cell apoptosis in the hippocampus of rats exposed to SPS by targeting σ-1R, which might be related to the mTOR signaling pathway.

Perioperative stroke: A perspective on challenges and opportunities for experimental treatment and diagnostic strategies

Perioperative stroke is an ischemic or hemorrhagic cerebral event during or up to 30 days after surgery. It is a feared condition due to a relatively high incidence, difficulties in timely detection, and unfavorable outcome compared to spontaneously occurring stroke. Recent preclinical data suggest that specific pathophysiological mechanisms such as aggravated neuroinflammation contribute to the detrimental impact of perioperative stroke. Conventional treatment options are limited in the perioperative setting due to difficult diagnosis and medications affecting coagulation in may cases. On the contrary, the chance to anticipate cerebrovascular events at the time of surgery may pave the way for prevention strategies. This review provides an overview on perioperative stroke incidence, related problems, and underlying pathophysiological mechanisms. Based on this analysis, we assess experimental stroke treatments including neuroprotective approaches, cell therapies, and conditioning medicine strategies regarding their potential use in perioperative stroke. Interestingly, the specific aspects of perioperative stroke might enable a more effective application of experimental treatment strategies such as classical neuroprotection whereas others including cell therapies may be of limited use. We also discuss experimental diagnostic options for perioperative stroke augmenting classical clinical and imaging stroke diagnosis. While some experimental stroke treatments may have specific advantages in perioperative stroke, the paucity of established guidelines or multicenter clinical research initiatives currently limits their thorough investigation.

The role of hypoxia in stem cell regulation of the central nervous system: From embryonic development to adult proliferation

Hypoxia is involved in the regulation of various cell functions in the body, including the regulation of stem cells. The hypoxic microenvironment is indispensable from embryonic development to the regeneration and repair of adult cells. In addition to embryonic stem cells, which need to maintain their self-renewal properties and pluripotency in a hypoxic environment, adult stem cells, including neural stem cells (NSCs), also exist in a hypoxic microenvironment. The subventricular zone (SVZ) and hippocampal dentate gyrus (DG) are the main sites of adult neurogenesis in the brain. Hypoxia can promote the proliferation, migration, and maturation of NSCs in these regions. Also, because most neurons in the brain are non-regenerative, stem cell transplantation is considered as a promising strategy for treating central nervous system (CNS) diseases. Hypoxic treatment also increases the effectiveness of stem cell therapy. In this review, we firstly describe the role of hypoxia in different stem cells, such as embryonic stem cells, NSCs, and induced pluripotent stem cells, and discuss the role of hypoxia-treated stem cells in CNS diseases treatment. Furthermore, we highlight the role and mechanisms of hypoxia in regulating adult neurogenesis in the SVZ and DG and adult proliferation of other cells in the CNS.

Strategies to Improve the Efficiency of Transplantation with Mesenchymal Stem Cells for the Treatment of Ischemic Stroke: A Review of Recent Progress

Cerebral ischemia is a common global disease that is characterized by a loss of neurological function and a poor prognosis in many patients. However, only a limited number of treatments are available for this condition at present. Given that the efficacies of these treatments tend to be poor, cerebral ischemia can create a significant burden on patients, families, and society. Mesenchymal stem cell (MSC) transplantation treatment has shown significant potential in animal models of ischemic stroke; however, the specific mechanisms underlying this effect have yet to be elucidated. Furthermore, clinical trials have yet to yield promising results. Consequently, there is an urgent need to identify new methods to improve the efficiency of MSC transplantation as an optimal treatment for ischemic stroke. In this review, we provide an overview of recent scientific reports concerning novel strategies that promote MSC transplantation as an effective therapeutic approach, including physical approaches, chemical agents, traditional Chinese medicines and extracts, and genetic modification. Our analyses showed that two key factors need to be considered if we are to improve the efficacy of MSC transplantation treatments: survival ability and homing ability. We also highlight the importance of other significant mechanisms, including the enhanced activation of MSCs to promote neurogenesis and angiogenesis, and the regulation of permeability in the blood-brain barrier. Further in-depth investigations of the specific mechanisms underlying MSC transplantation treatment will help us to identify effective methods that improve the efficiency of MSC transplantation for ischemic stroke. The development of safer and more effective methods will facilitate the application of MSC transplantation as a promising adjuvant therapy for the treatment of poststroke brain damage.

Targeting autophagy in ischemic stroke: From molecular mechanisms to clinical therapeutics

Stroke constitutes the second leading cause of death and a major cause of disability worldwide. Stroke is normally classified as either ischemic or hemorrhagic stroke (HS) although 87% of cases belong to ischemic nature. Approximately 700,000 individuals suffer an ischemic stroke (IS) in the US each year. Recent evidence has denoted a rather pivotal role for defective macroautophagy/autophagy in the pathogenesis of IS. Cellular response to stroke includes autophagy as an adaptive mechanism that alleviates cellular stresses by removing long-lived or damaged organelles, protein aggregates, and surplus cellular components via the autophagosome-lysosomal degradation process. In this context, autophagy functions as an essential cellular process to maintain cellular homeostasis and organismal survival. However, unchecked or excessive induction of autophagy has been perceived to be detrimental and its contribution to neuronal cell death remains largely unknown. In this review, we will summarize the role of autophagy in IS, and discuss potential strategies, particularly, employment of natural compounds for IS treatment through manipulation of autophagy.

Hypoxic preconditioning rejuvenates mesenchymal stem cells and enhances neuroprotection following intracerebral hemorrhage via the miR-326-mediated autophagy

BACKGROUND

Intracerebral hemorrhage (ICH) is a major public health concern, and mesenchymal stem cells (MSCs) hold great potential for treating ICH. However, the quantity and quality of MSCs decline in the cerebral niche, limiting the potential efficacy of MSCs. Hypoxic preconditioning is suggested to enhance the survival of MSCs and augment the therapeutic efficacy of MSCs in ICH. MicroRNAs (miRNAs) are known to mediate cellular senescence. However, the precise mechanism by which miRNAs regulate the senescence of hypoxic MSCs remains to be further studied. In the present study, we evaluated whether hypoxic preconditioning enhances the survival and therapeutic effects of olfactory mucosa MSC (OM-MSC) survival and therapeutic effects in ICH and investigated the mechanisms by which miRNA ameliorates hypoxic OM-MSC senescence.

METHODS

In the in vivo model, ICH was induced in mice by administration of collagenase IV. At 24 h post-ICH, 5 × 10⁵ normoxia or hypoxia OM-MSCs or saline was administered intracerebrally. The behavioral outcome, neuronal apoptosis, and OM-MSC survival were evaluated. In the in vitro model, OM-MSCs were exposed to hemin. Cellular senescence was examined by evaluating the expressions of P16INK4A, P21, P53, and by β-galactosidase staining. Microarray and bioinformatic analyses were performed to investigate the differences in the miRNA expression profiles between the normoxia and hypoxia OM-MSCs. Autophagy was confirmed using the protein expression levels of LC3, P62, and Beclin-1.

RESULTS

In the in vivo model, transplanted OM-MSCs with hypoxic preconditioning exhibited increased survival and tissue-protective capability. In the in vitro model, hypoxia preconditioning decreased the senescence of OM-MSCs exposed to hemin. Bioinformatic analysis identified that microRNA-326 (miR-326) expression was significantly increased in the hypoxia OM-MSCs compared with that of normoxia OM-MSCs. Upregulation of miR-326 alleviated normoxia OM-MSC senescence, whereas miR-326 downregulation increased hypoxia OM-MSC senescence. Furthermore, we showed that miR-326 alleviated cellular senescence by upregulating autophagy. Mechanistically, miR-326 promoted the autophagy of OM-MSCs via the PI3K signaling pathway by targeting polypyrimidine tract-binding protein 1 (PTBP1).

CONCLUSIONS

Our study shows that hypoxic preconditioning delays OM-MSC senescence and augments the therapeutic efficacy of OM-MSCs in ICH by upregulating the miR-326/PTBP1/PI3K-mediated autophagy.

Progress in Mesenchymal Stem Cell Therapy for Ischemic Stroke

Ischemic stroke (IS) is a serious cerebrovascular disease with high morbidity and disability worldwide. Despite the great efforts that have been made, the prognosis of patients with IS remains unsatisfactory. Notably, recent studies indicated that mesenchymal stem cell (MSCs) therapy is becoming a novel research hotspot with large potential in treating multiple human diseases including IS. The current article is aimed at reviewing the progress of MSC treatment on IS. The mechanism of MSCs in the treatment of IS involved with immune regulation, neuroprotection, angiogenesis, and neural circuit reconstruction. In addition, nutritional cytokines, mitochondria, and extracellular vesicles (EVs) may be the main mediators of the therapeutic effect of MSCs. Transplantation of MSCs-derived EVs (MSCs-EVs) affords a better neuroprotective against IS when compared with transplantation of MSCs alone. MSC therapy can prolong the treatment time window of ischemic stroke, and early administration within 7 days after stroke may be the best treatment opportunity. The deliver routine consists of intraventricular, intravascular, intranasal, and intraperitoneal. Furthermore, several methods such as hypoxic preconditioning and gene technology could increase the homing and survival ability of MSCs after transplantation. In addition, MSCs combined with some drugs or physical therapy measures also show better neurological improvement. These data supported the notion that MSC therapy might be a promising therapeutic strategy for IS. And the application of new technology will promote MSC therapy of IS.

Gut dysbiosis in stroke and its implications on Alzheimer's disease-like cognitive dysfunction

Various neurological disorders, such as stroke and Alzheimer's disease (AD), involve neuroinflammatory responses. The advent of the gut‐brain axis enhances our understanding of neurological disease progression and secondary cell death. Gut microbiomes, especially those associated with inflammation, may reflect the dysbiosis of both the brain and the gut, opening the possibility to utilize inflammatory microbiomes as biomarkers and therapeutic targets. The gut‐brain axis may serve as a contributing factor to disease pathology and offer innovative approaches in cell‐based regenerative medicine for the treatment of neurological diseases. In reviewing the pathogenesis of stroke and AD, we also discuss the effects of gut microbiota on cognitive decline and brain pathology. Although the underlying mechanism of primary cell death from either disease is clearly distinct, both may be linked to gut‐microbial dysfunction as a consequential aberration that is unique to each disease. Targeting peripheral cell death pathways that exacerbate disease symptoms, such as those arising from the gut, coupled with conventional central therapeutic approach, may improve stroke and AD outcomes.

Neurovascular Unit: A critical role in ischemic stroke

Ischemic stroke (IS), a common cerebrovascular disease, results from a sudden blockage of a blood vessel in the brain, thereby restricting blood supply to the area in question, and making a significantly negative impact on human health. Unfortunately, current treatments, that are mainly based on a recanalization of occluded blood vessels, are insufficient or inaccessible to many stroke patients. Recently, the profound influence of the neurovascular unit (NVU) on recanalization and the prognosis of IS have become better understood; in‐depth studies of the NVU have also provided novel approaches for IS treatment. In this article, we review the intimate connections between the changes in the NVU and IS outcomes, and discuss possible new management strategies having practical significance to IS. We discuss the concept of the NVU, as well as its roles in IS blood‐brain barrier regulation, cell preservation, inflammatory immune response, and neurovascular repair. Besides, we also summarize the influence of noncoding RNAs in NVU, and IS therapies targeting the NVU. We conclude that both the pathophysiological and neurovascular repair processes of IS are strongly associated with the homeostatic state of the NVU and that further research into therapies directed at the NVU could expand the range of treatments available for IS.

Growth factors-based beneficial effects of platelet lysate on umbilical cord-derived stem cells and their synergistic use in osteoarthritis treatment

Poor viability of mesenchymal stem cells (MSCs) at the transplanted site often hinders the efficacy of MSCs-based therapy. Platelet lysate (PL) contains rich amounts of growth factors, which benefits cell growth. This study aimed to explore how human PL benefits umbilical cord-derived MSCs (huc-MSCs), and whether they have synergistic potential in osteoarthritis (OA) treatment. As quality control, flow cytometry and specific staining were performed to identify huc-MSCs, and ELISA was used to quantify growth factors in PL. CCK-8 and flow cytometry assays were performed to evaluate the effects of PL on the cell viability and cell cycle progression of huc-MSCs. Wound healing and transwell assays were conducted to assess the migration of huc-MSCs. RNA sequencing, real time PCR, and Western blot assays were conducted to explore the growth factors-based mechanism of PL. The in vitro results showed that PL significantly promoted the proliferation, cell cycle, and migration of huc-MSCs by upregulating relevant genes/proteins and activating beclin1-dependent autophagy via the AMPK/mTOR signaling pathway. The main growth factors (PDGF-AA, IGF-1, TGF-β, EGF, and FGF) contributed to the effects of PL in varying degrees. The in vivo data showed that combined PL and huc-MSCs exerted significant synergistic effect against OA. The overall study determined the beneficial effects and mechanism of PL on huc-MSCs and indicated PL as an adjuvant for huc-MSCs in treating OA. This is the first report on the growth factors-based mechanism of PL on huc-MSCs and their synergistic application. It provides novel knowledge of PLʹs roles and offers a promising strategy for stem cell-based OA therapy by combining PL and huc-MSCs.

VX-765 enhances autophagy of human umbilical cord mesenchymal stem cells against stroke-induced apoptosis and inflammatory responses via AMPK/mTOR signaling pathway

INTRODUCTION

To investigate the protective effect of VX-765 on human umbilical mesenchymal stem cells (HUMSCs) in stroke and its mechanism.

MATERIALS AND METHODS

Mouse models of ischemic stroke were established using the distal middle cerebral artery occlusion (dMCAO) method. The dMCAO mice were accordingly transplanted with HUMSCs, VX-765-treated HUMSCs, or VX-765 + MHY185-treated HUMSCs. The HUMSCs were inserted with green fluorescent protein (GFP) for measurement of transplantation efficiency which was determined by immunofluorescence assay. Oxygen-glucose deprivation (OGD) was applied to mimic ischemic environment in vitro experiments, and the HUMSCs herein were transfected with AMPK inhibitor Compound C or autophagy inhibitor 3-MA. MTT assay was used to test the toxicity of VX-765. TUNEL staining and ELISA were applied to measure the levels of apoptosis and inflammatory cytokines (IL-1β, IL-6, and IL-10), respectively. The expressions of autophagy-associated proteins, AMPK, and mTOR were detected by Western blotting. TTC staining was applied to reveal the infarct lesions in the brain of dMCAO mice.

RESULTS

The pro-inflammatory cytokines, TUNEL-positive cells, and p-mTOR were decreased while the anti-inflammatory cytokine, autophagy-related proteins, and p-AMPK were increased in HUMSCs treated with VX-765 under OGD condition. Different expression patterns were found with the above factors after transfection of 3-MA or Compound C. The pro-inflammatory cytokines, TUNEL-positive cells, and infarct sections were decreased while the anti-inflammatory cytokine and autophagy-related proteins were increased in dMCAO mice transplanted with VX-765-treated HUMSCs compared to those transplanted with HUMSCs only. The autophagy was inhibited while p-mTOR was up-regulated after transfection of MHY.

CONCLUSION

VX-765 protects HUMSCs against stroke-induced apoptosis and inflammatory responses by activating autophagy via the AMPK/mTOR signaling pathway in vivo and in vitro.