Bone marrow-derived mesenchymal stem cells enhance autophagy via PI3K/AKT signalling to reduce the severity of ischaemia/reperfusion-induced lung injury

Placenta-derived mesenchymal stem cells protect against diabetic kidney disease by upregulating autophagy-mediated SIRT1/FOXO1 pathway

Diabetic kidney disease (DKD) is a common chronic microvascular complication of diabetes mellitus. Although studies have indicated the therapeutic potential of mesenchymal stem cells (MSCs) for DKD, the underlying molecular mechanisms remain unclear. Herein, we explored the renoprotective effect of placenta-derived MSCs (P-MSCs) and the potential mechanism of SIRT1/FOXO1 pathway-mediated autophagy in DKD. The urine microalbumin/creatinine ratio was determined using ELISA, and renal pathological changes were detected by special staining techniques. Immunofluorescence was used for detecting the renal tissue expression of podocin and nephrin; immunohistochemistry for the renal expression of autophagy-related proteins (LC3, Beclin-1, SIRT1, and FOXO1); and western blotting and PCR for the expression of podocyte autophagy- and pathway-related indicators. We found that P-MSCs ameliorated renal tubular injury and glomerular mesangial matrix deposition and alleviated podocyte damage in DKD rats. PMSCs enhanced autophagy levels and increased SIRT1 and FOXO1 expression in DKD rat renal tissue, whereas the autophagy inhibitor 3-methyladenine significantly attenuated the renoprotective effect of P-MSCs. P-MSCs improved HG-induced Mouse podocyte clone5(MPC5)injury, increased podocyte autophagy, and upregulated SIRT1 and FOXO1 expression. Moreover, downregulation of SIRT1 expression blocked the P-MSC-mediated enhancement of podocyte autophagy and improvement of podocyte injury. Thus, P-MSCs can significantly improve renal damage and reduce podocyte injury in DKD rats by modulating the SIRT1/FOXO1 pathway and enhancing podocyte autophagy.

The protective effect of carbamazepine on acute lung injury induced by hemorrhagic shock and resuscitation in rats

Hemorrhagic shock and resuscitation (HSR) enhances the risk of acute lung injury (ALI). This study investigated the protective effect of carbamazepine (CBZ) on HSR-induced ALI in rats. Male Sprague-Dawley rats were allocated into five distinct groups through randomization: control (SHAM), saline + HSR (HSR), CBZ + HSR (CBZ/HSR), dimethyl sulfoxide (DMSO) + HSR (DMSO/HSR), and CBZ + chloroquine (CQ) + HSR (CBZ/CQ/HSR). Subsequently, HSR models were established. To detect tissue damage, we measured lung histological changes, lung injury scores, and wet/dry weight ratios. We measured neutrophil counts as well as assessed the expression of inflammatory factors using RT-PCR to determine the inflammatory response. We detected autophagy-related proteins LC3II/LC3I, P62, Beclin-1, and Atg12-Atg5 using western blotting. Pretreatment with CBZ improved histopathological changes in the lungs and reduced lung injury scores. The CBZ pretreatment group exhibited significantly reduced lung wet/dry weight ratio, neutrophil aggregation and number, and inflammation factor (TNF-α and iNOS) expression. CBZ changed the expression levels of autophagy-related proteins (LC3II/LC3I, beclin-1, Atg12-Atg5, and P62), suggesting autophagy activation. However, after injecting CQ, an autophagy inhibitor, the beneficial effects of CBZ were reversed. Taken together, CBZ pretreatment improved HSR-induced ALI by suppressing inflammation, at least in part, through activating autophagy. Thus, our study offers a novel perspective for treating HSR-induced ALI.

Sevoflurane enhances autophagy via Rac1 to attenuate lung ischaemia‒reperfusion injury

Sevoflurane can attenuate lung ischaemia‒reperfusion injury (LIRI). However, the protective mechanism is unclear. In this study, we developed a LIRI model in vivo that animals (SD, n = 15) were subjected to the administration of 2.2 % sevoflurane 30 min before the onset of left pulmonary artery clamping for 45 min, which was then followed by 60 min of reperfusion treatment. Then, transcriptome sequencing was used to analyse lung tissues. Autophagy inhibition (3-MA) and Rac1-overexpression transfection plasmids were used in BEAS-2B cells, and BEAS-2B cells were subjected to hypoxia reoxygenation (H/R) and sevoflurane treatment. In both animal tissue and cells, inflammatory cytokines and apoptotic and autophagy molecules were measured by quantitative real-time PCR, western blotting and immunostaining. As a result, decreased arterial partial oxygen and damage to the histological structure of lung tissues were observed in LIRI model rats, and these effects were reversed by sevoflurane treatment. Activation of inflammation (elevated IL-1β, IL-6, and TNF-α) and apoptosis (elevated cleaved caspase3/caspase3 and Bax, degraded expression of Bcl2) and inhibition of autophagy (elevated P62, degraded expression of Beclin1 and LC3-II/LC3I) in the model group were ameliorated by sevoflurane. Transcriptome sequencing indicated that the PI3K/Akt pathway regulated by Rac1 plays an important role in LIRI. Furthermore, overexpression of Rac1 in a cell line inhibited the protective effect of sevoflurane in LIRI. Autophagy inhibition (3-MA) also prevented the protective effect of sevoflurane on inflammation and apoptosis. As shown in the present study, sevoflurane enhances autophagy via Rac1/PI3K/AKT signalling to attenuate lung ischaemia‒reperfusion injury.

Human umbilical cord mesenchymal stem cells alleviate fatty liver ischemia-reperfusion injury by activating autophagy through upregulation of IFNγ

Liver ischemia-reperfusion injury (IRI) is an important factor affecting the prognosis of liver transplantation, and extended criteria donors (e.g., steatosis donor livers) are considered to be more sensitive to ischemia-reperfusion injury in liver transplantation. Currently, the application of human umbilical cord mesenchymal stem cells (hMSCs) has great promise in the treatment of various injuries in the liver. This study aimed to investigate the therapeutic role and mechanism of hMSCs in fatty liver IRI. After more than 8 weeks of high-fat chow feeding, we constructed a fatty liver mouse model and established ischemic injury of about 70% of the liver. Six hours after IRI, liver injury was significantly alleviated in hMSCs-treated mice, and the expression levels of liver enzyme, inflammatory factor TNF-α, and apoptotic proteins were significantly lower than those of the control group, which were also significant in pathological sections. Transcriptomics analysis showed that IFNγ was significantly upregulated in the hMSCs group. Mechanistically, IFNγ, which activates the MAPK pathway, is a potent agonist that promotes the occurrence of autophagy in hepatocytes to exert a protective function, which was confirmed by in vitro experiments. In summary, hMSCs treatment could slow down IRI in fatty liver by activating autophagy through upregulation of IFNγ, and this effect was partly direct.

Research Progress on Autophagy Regulation by Active Ingredients of Traditional Chinese Medicine in the Treatment of Acute Lung Injury

Autophagy is a highly conserved process that maintains cell stability in eukaryotes, participates in the turnover of intracellular substances to maintain cell function, helps to resist pathogen invasion, and improves cell tolerance to environmental changes. Autophagy has been observed in many diseases, and the symptoms of these diseases are significantly improved by regulating autophagy. Autophagy is also involved in the development of lung diseases. Studies have shown that autophagy may play a beneficial or harmful role in acute lung injury (ALI), and ALI has been treated with traditional Chinese medicine designed to promote or inhibit autophagy. In this paper, the molecular mechanism and common pathways regulating autophagy and the relationship between autophagy and ALI are introduced, and the active ingredients of traditional Chinese medicine that improve ALI symptoms by regulating autophagy are summarized.

The multifunctional roles of autophagy in the innate immune response: Implications for regulation of transplantation rejection

Organ transplantation is the main treatment for end-stage organ failure, which has rescued tens of thousands of lives. Immune rejection is the main factor affecting the survival of transplanted organs. How to suppress immune rejection is an important goal of transplantation research. A graft first triggers innate immune responses, leading to graft inflammation, tissue injury and cell death, followed by adaptive immune activation. At present, the importance of innate immunity in graft rejection is poorly understood. Autophagy, an evolutionarily conserved intracellular degradation system, is proven to be involved in regulating innate immune response following graft transplants. Moreover, there is evidence indicating that autophagy can regulate graft dysfunction. Although the specific mechanism by which autophagy affects graft rejection remains unclear, autophagy is involved in innate immune signal transduction, inflammatory response, and various forms of cell death after organ transplantation. This review summarizes how autophagy regulates these processes and proposes potential targets for alleviating immune rejection.

miR-193-5p negatively regulates PIK3CD to promote crop fibrocyte proliferation in pigeon (Columba livia)

The crop of pigeon has specific characteristics as producing crop milk in the lactating period. However, the exact mechanisms underlying the regulation of crop lactation remain unclear. miRNAs, the essential regulators of gene expression, are implicated in various physiological and biological activities. In this study, we discovered a new miRNA that regulated phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta (PIK3CD) and crop fibrocyte proliferation. Results of the luciferase reporter assay suggested that miR-193-5p suppressed PIK3CD expression by targeting a conserved binding site in the 3'-untranslated region (UTR) of PIK3CD mRNA. MiR-193-5p promoted crop fibrocyte proliferation and migration, whereas PIK3CD inhibited these effects. These findings suggested an important regulatory role of miR-193-5p in crop fibrocyte proliferation, suggesting that miR-193-5p and PIK3CD might be important regulators of crop milk production.

The pathological and therapeutic roles of mesenchymal stem cells in preeclampsia

Mesenchymal stem cells (MSCs) have made progress in the treatment of ischemic and inflammatory diseases. Preeclampsia (PE) is characterized by placenta ischemic and inflammatory injury. Our paper summarized the new role of MSCs in PE pathology and its potency in PE therapy and analyzed its current limitations. Intravenously administered MSCs dominantly distributed in perinatal tissues. There may be additional advantages to using MSCs-based therapies for reproductive disorders. It will provide new ideas for future research in this field.

Role of Chaperone-Mediated Autophagy in Ageing Biology and Rejuvenation of Stem Cells

What lies at the basis of the mechanisms that regulate the maintenance and self-renewal of pluripotent stem cells is still an open question. The control of stemness derives from a fine regulation between transcriptional and metabolic factors. In the last years, an emerging topic has concerned the involvement of Chaperone-Mediated Autophagy (CMA) as a key mechanism in stem cell pluripotency control acting as a bridge between epigenetic, transcriptional and differentiation regulation. This review aims to clarify this new and not yet well-explored horizon discussing the recent studies regarding the CMA impact on embryonic, mesenchymal, and haematopoietic stem cells. The review will discuss how CMA influences embryonic stem cell activity promoting self-renewal or differentiation, its involvement in maintaining haematopoietic stem cell function by increasing their functionality during the normal ageing process and its effects on mesenchymal stem cells, in which modulation of CMA regulates immunosuppressive and differentiation properties. Finally, the importance of these new discoveries and their relevance for regenerative medicine applications, from transplantation to cell rejuvenation, will be addressed.

BMSCs mediates endothelial cell autophagy by upregulating miR-155-5p to alleviate ventilator-induced lung injury

In this study, we explored to detect the effects and mechanism of bone-marrow-derived mesenchymal stem cells (BMSCs) on ventilator-induced lung injury (VILI). We transplanted BMSCs in mice and then induced VILI using mechanical ventilation (MV) treatment. The pathological changes, the content of PaO₂ and PaCO₂ , wet/dry weight ratio (W/D) of the lung, levels of tumor necrosis factor-α and interleukin-6 in bronchoalveolar lavage fluid, and apoptosis were detected. The autophagy-associated factor p62, LC3, and Beclin-1 expression were analyzed by western blot. The quantitative polymerase chain reaction was applied to detect abnormally expressed microRNAs, including miR-155-5p. Subsequently, we overexpressed miR-155-5p in VILI mice to detect the effects of miR-155-5p on MV-induced lung injury. Then, we carried out bioinformatics analysis to verify the BMSCs-regulated miR-155-5p that target messenger RNA. It was observed that BMSCs transplantation mitigated the severity of VILI in mice. BMSCs transplantation reduced lung inflammation, strengthened the arterial oxygen partial pressure, and reduced apoptosis and the W/D of the lung. BMSCs promoted autophagy of pulmonary endothelial cells accompanied by decreased p62 and increased LC3 II/I and Beclin-1. BMSCs increased the levels of miR-155-5p in VILI mice. Overexpression of miR-155-5p alleviated lung injury in VILI mice following reduced apoptosis and increased autophagy. Finally, TAB2 was identified as a downstream target of miR-155-5p and regulated by miR-155-5p. BMSCs may protect lung tissues from MV-induced injury, inhibit lung inflammation, promote autophagy through upregulating of miR-155-5p.

Menstrual blood-derived endometrial stem cells ameliorate the viability of ovarian granulosa cells injured by cisplatin through activating autophagy

Although the cancer incidence showed a yearly increasing trend, the long-term survival rate of cancer patients significantly increased with the continuous improvements in cancer diagnosis and treatment. Therefore, recent strategies for cancer treatment not only focus on improving the survival rate of patients but also simultaneously consider the life quality of cancer patients, especially for those with fertility requirements. Stem cell-based therapies have exhibited promising improvement in various disease treatments, and provide hope for diseases without effective treatment. Menstrual blood-derived endometrial stem cells (MenSCs) can be noninvasively and periodically obtained from discarded menstrual blood samples and exhibit high proliferative capacity, low immunogenicity and autologous transplantation. As expected, MenSCs treatment effectively improved the viability of cisplatin-injured ovarian granulosa cells (GCs) and significantly upregulated their antiapoptotic capacity. Further results demonstrated that MenSCs treatment significantly upregulated autophagy activity in cisplatin-injured ovarian GCs, and the degree of autophagy activation was positively correlated with the viability improvement of ovarian GCs, while autophagy inhibitors significantly impaired MenSC-promoted viability improvement of cisplatin-injured ovarian GCs. Additionally, MenSCs treatment can also significantly promote the proliferation of normal GCs by activating the PI3K/Akt signaling pathway. Conclusively, MenSCs treatment not only enhanced the antiapoptotic capacity and survival of cisplatin-injured ovarian GCs by upregulating autophagy activity but also improved the viability of normal ovarian GCs by activating the PI3K/Akt signal pathway. These results provide a theoretical and experimental foundation for the clinical application of MenSCs in improving chemotherapy-induced ovarian injury and delaying ovarian senescence.

Are mesenchymal stem cells able to manage cytokine storm in COVID-19 patients? A review of recent studies

The Covid-19 disease has recently become one of the biggest challenges globally, and there is still no specific medication. Findings showed the immune system in severe Covid-19 patients loses regulatory control of pro-inflammatory cytokines, especially IL-6 production, called the "Cytokine storm" process. This process can cause injury to vital organs, including lungs, kidneys, liver, and ultimately death if not inhibited. While many treatments have been proposed to reduce cytokine storm, but the safety and effectiveness of each of them are still in doubt. Mesenchymal stem cells (MSCs) are multipotent cells with self-renewal potential capable of suppressing overactive immune responses and leading to tissue restoration and repair. These immuno-modulatory properties of MSCs and their derivatives (like exosomes) can improve the condition of Covid-19 patients with serious infectious symptoms caused by adaptive immune system dysfunction. Many clinical trials have been conducted in this field using various MSCs around the world. Some of these have been published and summarized in the present article, while many have not yet been completed. Based on these available data, MSCs can reduce inflammatory cytokines, increase oxygen saturation, regenerate lung tissue and improve clinical symptoms in Covid-19 patients. The review article aims to collect available clinical data in more detail and investigate the role of MSCs in reducing cytokine storms as well as improving clinical parameters of Covid-19 patients for use in future clinical studies.

Mesenchymal Stem Cells and Tuberculosis: Clinical Challenges and Opportunities

Tuberculosis (TB) is one of the communicable diseases caused by Mycobacterium tuberculosis (Mtb) infection, affecting nearly one-third of the world's population. However, because the pathogenesis of TB is still not fully understood and the development of anti-TB drug is slow, TB remains a global public health problem. In recent years, with the gradual discovery and confirmation of the immunomodulatory properties of mesenchymal stem cells (MSCs), more and more studies, including our team's research, have shown that MSCs seem to be closely related to the growth status of Mtb and the occurrence and development of TB, which is expected to bring new hope for the clinical treatment of TB. This article reviews the relationship between MSCs and the occurrence and development of TB and the potential application of MSCs in the treatment of TB.

Hypoxic mesenchymal stem cells ameliorate acute kidney ischemia-reperfusion injury via enhancing renal tubular autophagy

BACKGROUND

Acute kidney injury (AKI) is an emerging global healthcare issue without effective therapy yet. Autophagy recycles damaged organelles and helps maintain tissue homeostasis in acute renal ischemia-reperfusion (I/R) injury. Hypoxic mesenchymal stem cells (HMSCs) represent an innovative cell-based therapy in AKI. Moreover, the conditioned medium of HMSCs (HMSC-CM) rich in beneficial trophic factors may serve as a cell-free alternative therapy. Nonetheless, whether HMSCs or HMSC-CM mitigate renal I/R injury via modulating tubular autophagy remains unclear.

METHODS

Renal I/R injury was induced by clamping of the left renal artery with right nephrectomy in male Sprague-Dawley rats. The rats were injected with either PBS, HMSCs, or HMSC-CM immediately after the surgery and sacrificed 48 h later. Renal tubular NRK-52E cells subjected to hypoxia-reoxygenation (H/R) injury were co-cultured with HMSCs or treated with HMSC-CM to assess the regulatory effects of HSMCs on tubular autophagy and apoptosis. The association of tubular autophagy gene expression and renal recovery was also investigated in patients with ischemic AKI.

RESULT

HMSCs had a superior anti-oxidative effect in I/R-injured rat kidneys as compared to normoxia-cultured mesenchymal stem cells. HMSCs further attenuated renal macrophage infiltration and inflammation, reduced tubular apoptosis, enhanced tubular proliferation, and improved kidney function decline in rats with renal I/R injury. Moreover, HMSCs suppressed superoxide formation, reduced DNA damage and lipid peroxidation, and increased anti-oxidants expression in renal tubular epithelial cells during I/R injury. Co-culture of HMSCs with H/R-injured NRK-52E cells also lessened tubular cell death. Mechanistically, HMSCs downregulated the expression of pro-inflammatory interleukin-1β, proapoptotic Bax, and caspase 3. Notably, HMSCs also upregulated the expression of autophagy-related LC3B, Atg5 and Beclin 1 in renal tubular cells both in vivo and in vitro. Addition of 3-methyladenine suppressed the activity of autophagy and abrogated the renoprotective effects of HMSCs. The renoprotective effect of tubular autophagy was further validated in patients with ischemic AKI. AKI patients with higher renal LC3B expression were associated with better renal recovery.

CONCLUSION

The present study describes that the enhancing effect of MSCs, and especially of HMCSs, on tissue autophagy can be applied to suppress renal tubular apoptosis and attenuate renal impairment during renal I/R injury in the rat. Our findings provide further mechanistic support to HMSCs therapy and its investigation in clinical trials of ischemic AKI.

Oxidative Stress, Inflammation, and Autophagy: Potential Targets of Mesenchymal Stem Cells-Based Therapies in Ischemic Stroke

Ischemic stroke is a leading cause of death worldwide; currently available treatment approaches for ischemic stroke are to restore blood flow, which reduce disability but are time limited. The interruption of blood flow in ischemic stroke contributes to intricate pathophysiological processes. Oxidative stress and inflammatory activity are two early events in the cascade of cerebral ischemic injury. These two factors are reciprocal causation and directly trigger the development of autophagy. Appropriate autophagy activity contributes to brain recovery by reducing oxidative stress and inflammatory activity, while autophagy dysfunction aggravates cerebral injury. Abundant evidence demonstrates the beneficial impact of mesenchymal stem cells (MSCs) and secretome on cerebral ischemic injury. MSCs reduce oxidative stress through suppressing reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation and transferring healthy mitochondria to damaged cells. Meanwhile, MSCs exert anti-inflammation properties by the production of cytokines and extracellular vesicles, inhibiting proinflammatory cytokines and inflammatory cells activation, suppressing pyroptosis, and alleviating blood–brain barrier leakage. Additionally, MSCs regulation of autophagy imbalances gives rise to neuroprotection against cerebral ischemic injury. Altogether, MSCs have been a promising candidate for the treatment of ischemic stroke due to their pleiotropic effect.

Bone marrow-derived mesenchymal stem cells modulate autophagy in RAW264.7 macrophages via the phosphoinositide 3-kinase/protein kinase B/heme oxygenase-1 signaling pathway under oxygen-glucose deprivation/restoration conditions

Background

Autophagy of alveolar macrophages is a crucial process in ischemia/reperfusion injury-induced acute lung injury (ALI). Bone marrow-derived mesenchymal stem cells (BM-MSCs) are multipotent cells with the potential for repairing injured sites and regulating autophagy. This study was to investigate the influence of BM-MSCs on autophagy of macrophages in the oxygen-glucose deprivation/restoration (OGD/R) microenvironment and to explore the potential mechanism.

Methods

We established a co-culture system of macrophages (RAW264.7) with BM-MSCs under OGD/R conditions in vitro. RAW264.7 cells were transfected with recombinant adenovirus (Ad-mCherry-GFP-LC3B) and autophagic status of RAW264.7 cells was observed under a fluorescence microscope. Autophagy-related proteins light chain 3 (LC3)-I, LC3-II, and p62 in RAW264.7 cells were detected by Western blotting. We used microarray expression analysis to identify the differently expressed genes between OGD/R treated macrophages and macrophages co-culture with BM-MSCs. We investigated the gene heme oxygenase-1 (HO-1), which is downstream of the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signaling pathway.

Results

The ratio of LC3-II/LC3-I of OGD/R treated RAW264.7 cells was increased (1.27 ± 0.20 vs. 0.44 ± 0.08, t = 6.67, P < 0.05), while the expression of p62 was decreased (0.77 ± 0.04 vs. 0.95 ± 0.10, t = 2.90, P < 0.05), and PI3K (0.40 ± 0.06 vs. 0.63 ± 0.10, t = 3.42, P < 0.05) and p-Akt/Akt ratio was also decreased (0.39 ± 0.02 vs. 0.58 ± 0.03, t = 9.13, P < 0.05). BM-MSCs reduced the LC3-II/LC3-I ratio of OGD/R treated RAW264.7 cells (0.68 ± 0.14 vs. 1.27 ± 0.20, t = 4.12, P < 0.05), up-regulated p62 expression (1.10 ± 0.20 vs. 0.77 ± 0.04, t = 2.80, P < 0.05), and up-regulated PI3K (0.54 ± 0.05 vs. 0.40 ± 0.06, t = 3.11, P < 0.05) and p-Akt/Akt ratios (0.52 ± 0.05 vs. 0.39 ± 0.02, t = 9.13, P < 0.05). A whole-genome microarray assay screened the differentially expressed gene HO-1, which is downstream of the PI3K/Akt signaling pathway, and the alteration of HO-1 mRNA and protein expression was consistent with the data on PI3K/Akt pathway.

Conclusions

Our results suggest the existence of the PI3K/Akt/HO-1 signaling pathway in RAW264.7 cells under OGD/R circumstances in vitro, revealing the mechanism underlying BM-MSC-mediated regulation of autophagy and enriching the understanding of potential therapeutic targets for the treatment of ALI.

CUEDC2 ablation enhances the efficacy of mesenchymal stem cells in ameliorating cerebral ischemia/reperfusion insult

Mesenchymal stem cell (MSC) therapy has been reported to be a promising therapeutic option for cerebral ischemia/reperfusion (I/R) insult. However, the poor survival rate of engrafted MSCs under unfavorable cerebral I/R-induced microenvironment inhibits their efficiency during clinical application. CUE domain-containing 2(CUECD2) exhibits its protective role on cardiomyocytes by mediating the antioxidant capacity. Our study explored the functional role of CUEDC2 in cerebral I/R challenge and determined whether CUECD2-modified MSCs could improve the efficacy of treatment of the insulted neurons. We also evaluated the possible mechanisms involved in cerebral I/R condition. Cerebral I/R stimulation suppressed CUEDC2 levels in brain tissues and neurons. siRNA-CUEDC2 in neurons significantly inhibited cerebral I/R-induced apoptosis and oxidative stress levels in vitro. Moreover, siRNA-CUEDC2 in the MSCs group remarkably enhanced the therapeutic efficacies in cerebral I/R-induced neuron injury and brain tissue impairment when compared to the non-genetic MSCs treatment group. At the molecular level, siRNA-CUEDC2 in MSCs markedly enhanced its antioxidant and anti-inflammatory effect in co-cultured neurons by upregulating glutathione peroxidase 1 (GPX1) expression levels while suppressing NF-kB activation. These findings provide a novel strategy for the utilization of MSCs to promote cerebral ischemic stroke outcomes.

Combination of mesenchymal stromal cells and machine perfusion is a novel strategy for organ preservation in solid organ transplantation

Organ preservation is a prerequisite for an urgent increase in the availability of organs for solid organ transplantation (SOT). An increasing amount of expanded criteria donor (ECD) organs are used clinically. Currently, the paradigm of organ preservation is shifting from simple reduction of cellular metabolic activity to maximal simulation of an ex vivo physiological microenvironment. An ideal organ preservation technique should not only preserve isolated organs but also offer the possibility of rehabilitation and evaluation of organ function prior to transplantation. Based on the fact that mesenchymal stromal cells (MSCs) possess strong regeneration properties, the combination of MSCs with machine perfusion (MP) is expected to be superior to conventional preservation methods. In recent years, several studies have attempted to use this strategy for SOT showing promising outcomes. With better organ function during ex vivo preservation and the potential of utilization of organs previously deemed untransplantable, this strategy is meaningful for patients with organ failure to help overcome organ shortage in the field of SOT.

Mesenchymal stromal cells to fight SARS-CoV-2: Taking advantage of a pleiotropic therapy

The devastating global impact of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has prompted scientists to develop novel strategies to fight Coronavirus Disease of 2019 (COVID-19), including the examination of pre-existing treatments for other viral infections in COVID-19 patients. This review provides a reasoned discussion of the possible use of Mesenchymal Stromal Cells (MSC) or their products as a treatment in SARS-CoV-2-infected patients. The main benefits and concerns of using this cellular therapy, guided by preclinical and clinical data obtained from similar pathologies will be reviewed. MSC represent a highly immunomodulatory cell population and their use may be safe according to clinical studies developed in other pathologies. Notably, four clinical trials and four case reports that have already been performed in COVID-19 patients obtained promising results. The clinical application of MSC in COVID-19 is very preliminary and further investigational studies are required to determine the efficacy of the MSC therapy. Nevertheless, these preliminary studies were important to understand the therapeutic potential of MSC in COVID-19. Based on these encouraging results, the United States Food and Drug Administration (FDA) authorized the compassionate use of MSC, but only in patients with Acute Respiratory Distress Syndrome (ARDS) and a poor prognosis. In fact, patients with severe SARS-CoV-2 can present infection and tissue damage in different organs, such as lung, heart, liver, kidney, gut and brain, affecting their function. MSC may have pleiotropic activities in COVID-19, with the capacity to fight inflammation and repair lesions in several organs.

Acute and chronic effects of polystyrene microplastics on brine shrimp: First evidence highlighting the molecular mechanism through transcriptome analysis

Microplastics contamination is one of the leading environmental catastrophes for the marine ecosystem, but the molecular toxicity mechanism of those microplastics remains elusive. This study aims to determine the acute and chronic toxicity after exposure to polystyrene microplastics in brine shrimp with various concentrations. Our results demonstrated that acute exposure to polystyrene microplastics induced no significant effects on the survival of brine shrimp. Interestingly, the concentration-dependent increase in both bioaccumulation and the generation of reactive oxygen species (ROS) was observed after acute and chronic exposure. Moreover, the histopathology analysis revealed the deformation of epithelial cells in the midgut region after both acute exposures at 100 mg/L and chronic exposure at 1 mg/L to polystyrene microplastics. To elucidate the underlying mechanisms of microplastics-mediated toxicity, the transcriptome analysis was performed after chronic exposure, and the result showed 721 differentially expressed genes (DEGs) associated with 156 known KEGG pathways. 292 DEGs genes were significantly upregulated and 429 genes were significantly downregulated. The transcriptome analysis further revealed the DEGs related pathways. Taken together, this study not only highlighted the negative effects but also provided detailed sequencing data from transcriptome profiling to enhance our understanding of the molecular toxicity of polystyrene microplastics in brine shrimp.

Prevention and treatment of radiation-induced lung injury

Radiation-induced lung injury (RILI) is a common complication in cancer patients receiving local thoracic radiation and bone marrow transplantation conditioning. It is divided into early-stage radiation pneumonitis and advanced radiation fibrosis of the lung. This severely hampers the quality of life and survival of cancer patients. Meanwhile, RILI is a major factor limiting radiation doses in clinical practice, which affects the local control of cancer. Unfortunately, the mechanism of RILI is still not well defined, and there are no treatment options available for these patients. In this review we summarize the methods and agents used for the treatment and prevention of RILI, with the aim of increasing understanding of RILI.

Unraveling the therapeutic effects of mesenchymal stem cells in asthma

Asthma is a chronic inflammatory disease associated with airway hyper-responsiveness, chronic inflammatory response, and excessive structural remodeling. The current therapeutic strategies in asthmatic patients are based on controlling the activity of type 2 T helper lymphocytes in the pulmonary tissue. However, most of the available therapies are symptomatic and expensive and with diverse side outcomes in which the interruption of these modalities contributes to the relapse of asthmatic symptoms. Up to date, different reports highlighted the advantages and beneficial outcomes regarding the transplantation of different stem cell sources, and relevant products from for the diseases' alleviation and restoration of injured sites. However, efforts to better understand by which these cells elicit therapeutic effects are already underway. The precise understanding of these mechanisms will help us to translate stem cells into the clinical setting. In this review article, we described current knowledge and future perspectives related to the therapeutic application of stem cell-based therapy in animal models of asthma, with emphasis on the underlying therapeutic mechanisms.

An injectable liposome for sustained release of tanshinone IIA to the treatment of acute blunt muscle injury by augmenting autophagy and alleviating oxidative stress

Acute blunt skeletal muscle injury occurs frequently in sports and traffic accidents, and even leads to muscle necrosis and impaired functionality. Current treatment options for muscle injuries remain suboptimal and often result in delayed/incomplete recovery of damaged muscles. Tanshinone IIA is extracted from Salvia Miltiorrhizae, which is effective in the treatment of injury repair. But the clinical application of tanshinone IIA is limited due to its low water solubility, low permeability to biofilm and low bioavailability. In this study, tanshinone IIA liposomes were prepared to improve the bioavailability and sustained release of tanshinone IIA. The particle size, dispersion coefficient, zeta potential, encapsulation efficiency (EE) and drug loading (DL) of tanshinone IIA liposomes were 150.67 ± 27.23 nm, 0.20 ± 0.015, -8.73 ± 2.28 mV, 70.32 ± 4.04% and 15.63%, respectively. The results of quantitative real-time polymerase chain reaction (QRT-PCR) showed that tanshinone IIA liposome significantly promoted the expression of vimentin and reduce MHCIIB expression compared with other groups (P < 0.05). Western blotting showed that tanshinone IIA liposome could effectively promote the expression of autophagy-related proteins (VPS34, Beclin 1 and CTSD) and decrease p62 expression levels to treat injured muscle. Through HE, immunohistochemistry, ELISA and serological tests, we found that tanshinone IIA liposome not only effectively promoted the expression of desmin, but also reduced the expression of collagen-I and inhibited the production of pro-inflammatory factors, such as tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) (P < 0.05). In addition, tanshinone IIA liposome therapy significantly reduced the level of malondialdehyde (MDA) and increased the activity of superoxide dismutase (SOD) after muscle injury compared with other groups (P < 0.05). In conclusion, tanshinone IIA liposome possesses an effective therapeutic effect on acute blunt muscle injury in rats by augmenting autophagy and alleviating oxidative stress. The continuous release of tanshinone IIA encapsulated by liposomes for disease treatment provide a new idea for the efficient and safe use of drugs with low lipid solubility and bioavailability for the treatment of acute blunt muscle injury and repair of other injuries.

Cell-Based Therapeutic Approaches for Cystic Fibrosis

Cystic Fibrosis (CF) is a chronic autosomal recessive disease caused by defects in the cystic fibrosis transmembrane conductance regulator gene (CFTR). Cystic Fibrosis affects multiple organs but progressive remodeling of the airways, mucus accumulation, and chronic inflammation in the lung, result in lung disease as the major cause of morbidity and mortality. While advances in management of CF symptoms have increased the life expectancy of this devastating disease, and there is tremendous excitement about the potential of new agents targeting the CFTR molecule itself, there is still no curative treatment. With the recent advances in the identification of endogenous airway progenitor cells and in directed differentiation of pluripotent cell sources, cell-based therapeutic approaches for CF have become a plausible treatment method with the potential to ultimately cure the disease. In this review, we highlight the current state of cell therapy in the CF field focusing on the relevant autologous and allogeneic cell populations under investigation and the challenges associated with their use. In addition, we present advances in induced pluripotent stem (iPS) cell approaches and emerging new genetic engineering methods, which have the capacity to overcome the current limitations hindering cell therapy approaches.

Silica dust exposure induces autophagy in alveolar macrophages through switching Beclin1 affinity from Bcl-2 to PIK3C3

Increased deposition of silica dust in pulmonary interstitial tissues leads to silicosis, in which autophagy plays a defensive role in silica dust-associated stress response and cell death. Our previous studies revealed that silica dust exposure contributed to autophagy in pulmonary macrophages in vivo, while the specific regulatory mechanism is still unclear. This study aimed to figure out the regulatory mechanism as well as the role of autophagy in the pathogenesis of experimental silicosis. We used 3-methyladenine (3-MA) and ABT-737 to suppress the expression of phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3) and B cell leukemia/lymphoma 2 (Bcl-2), two critical initiators of autophagy, and detected and evaluated the autophagy in NR8383 cells with or without silica dust exposure. We found that exposure of silica dust increased autophagy in NR8383 cells and elevated the expression of Beclin1 and PIK3C3, but it reduced the expression of Bcl-2. The relationship among Beclin1, PIK3C3, and Bcl-2 were then investigated using immunoprecipitation analysis, and we found that suppression of PIK3C3 and/or Bcl-2 using 3-MA and/or ABT-737 could alter the autophagy induced by silica dust in NR8383 cells, and the complexes of Beclin1/PIK3C3 and Beclin1/Bcl-2 were both downregulated, which may be that inhibition of PIK3C3 and Bcl-2 altered the affinity of Beclin1 with PIK3C3 and Bcl-2 and lead to the silence of PIK3C3 signaling. These findings indicate that silica dust exposure induces autophagy via changing the connectivity of Beclin1 from Bcl-2 to PIK3C3.

Mesenchymal stem cells repair bone marrow damage of aging rats and regulate autophagy and aging genes

The current study investigated the role of mesenchymal stem cells (MSCs) in repairing senile bone marrow injury and the underlying mechanism. Adenoviral vectors expressing green fluorescent protein (GFP) were used to label MSCs. The level of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) were detected by thiobarbituric acid (TBA) and xanthine oxidation (XTO) methods. The proportions of CD34, CD3⁺ cells, cell proliferation and apoptosis were determined by flow cytometry, Cell counting kit (CCK)-8 and comet assay. Tissues were stained by haematoxylin-eosin (HE) staining and their changes were observed under a transmission electron microscopy. Expression levels of age-related and autophagy-related genes were detected by RT-qPCR and Western Blot. MSCs were successfully implanted into the bone marrow of aging rats. We found that the SOD activity was increased and MDA content was reduced in MSCs group. The proportions of CD34 cells were significantly more in the MSCs group than those in the Model group, and bone marrow cell colony formation and cell viability were both greatly increased in MSCs group. The proportions of CD3⁺ cells and level of Vascular endothelial growth factor (VEGF) were increased significantly, while IL-6 level was reduced greatly in MSCs group. Moreover, the bone marrow tissues of the model group were severely damaged, but those of the MSCs group were significantly improved. In addition, MSCs were involved in regulation of aging-related genes and autophagy-related genes. In conclusion, our findings showed that MSCs can repair bone marrow damage in aging rats, and regulate aging- and autophagy-related genes and immune response. SIGNIFICANCE: This study investigated the role of MSCs in the repair of senile bone marrow injury and the underlying mechanism. The effects of MSCs on physiological and biochemical indicators, cell function, tissue structure differences and pathological changes in aging rats were studied. It was found that MSCs can repair bone marrow damage in aging rats. MSCs regulate aging and autophagy-related genes and its involvement in immune response. Our findings improve the understandings on the regulatory mechanism of MSCs and provide key evidence for the study of MSCs in bone marrow repair.

Rationale for the clinical use of adipose-derived mesenchymal stem cells for COVID-19 patients

In late 2019, a novel coronavirus (SARS-CoV-2) emerged in Wuhan, capital city of Hubei province in China. Cases of SARS-CoV-2 infection quickly grew by several thousand per day. Less than 100 days later, the World Health Organization declared that the rapidly spreading viral outbreak had become a global pandemic. Coronavirus disease 2019 (COVID-19) is typically associated with fever and respiratory symptoms. It often progresses to severe respiratory distress and multi-organ failure which carry a high mortality rate. Older patients or those with medical comorbidities are at greater risk for severe disease. Inflammation, pulmonary edema and an over-reactive immune response can lead to hypoxia, respiratory distress and lung damage. Mesenchymal stromal/stem cells (MSCs) possess potent and broad-ranging immunomodulatory activities. Multiple in vivo studies in animal models and ex vivo human lung models have demonstrated the MSC's impressive capacity to inhibit lung damage, reduce inflammation, dampen immune responses and aid with alveolar fluid clearance. Additionally, MSCs produce molecules that are antimicrobial and reduce pain. Upon administration by the intravenous route, the cells travel directly to the lungs where the majority are sequestered, a great benefit for the treatment of pulmonary disease. The in vivo safety of local and intravenous administration of MSCs has been demonstrated in multiple human clinical trials, including studies of acute respiratory distress syndrome (ARDS). Recently, the application of MSCs in the context of ongoing COVID-19 disease and other viral respiratory illnesses has demonstrated reduced patient mortality and, in some cases, improved long-term pulmonary function. Adipose-derived stem cells (ASC), an abundant type of MSC, are proposed as a therapeutic option for the treatment of COVID-19 in order to reduce morbidity and mortality. Additionally, when proven to be safe and effective, ASC treatments may reduce the demand on critical hospital resources. The ongoing COVID-19 outbreak has resulted in significant healthcare and socioeconomic burdens across the globe. There is a desperate need for safe and effective treatments. Cellular based therapies hold great promise for the treatment of COVID-19. This literature summary reviews the scientific rationale and need for clinical studies of adipose-derived stem cells and other types of mesenchymal stem cells in the treatment of patients who suffer with COVID-19.

Forkhead box K1 regulates the malignant behavior of gastric cancer by inhibiting autophagy

Background

Forkhead box K1 (FOXK1) is a transcription factor that contributes to cancer development, but it is unclear how FOXK1 regulates the proliferation and migration of gastric cancer (GC) cells. The purpose of this study was to investigate the clinical significance, biological function, and molecular mechanisms of FOXK1 in GC.

Methods

We conducted bioinformatics assays and western blotting to assess FOXK1 expression. Then, we performed immunohistochemistry (IHC) with tissue microarrays (TMAs) to assess FOXK1 expression in order to identify an association between FOXK1 expression levels and clinical parameters. We used 5-ethynyl-2'-deoxyuridine (EdU), wound healing and Transwell assays to determine whether FOXK1 promotes malignant behaviors in GC. Furthermore, immunofluorescence staining, transmission electron microscopy and western blotting were used to verify an association between FOXK1 and autophagy.

Results

We observed high levels of FOXK1 expression in GC tissues, which were associated with the degree of malignancy in GC. FOXK1 promotes the malignant behavior of GC by regulating autophagy via activation of the class I phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway and inhibition of the expression of class III PI3K.

Conclusions

These findings provide a new target for the comprehensive treatment of GC by highlighting the relationship between FOXK1 and malignant behaviors in GC.

Combined Antioxidant, Anti-inflammaging and Mesenchymal Stem Cell Treatment: A Possible Therapeutic Direction in Elderly Patients with Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) is a worldwide health problem associated with high morbidity and mortality, especially in elderly patients. Aging functions include mitochondrial dysfunction, cell-to-cell information exchange, protein homeostasis and extracellular matrix dysregulation, which are closely related to chronic inflammatory response and oxidation-antioxidant imbalance in the pathogenesis of COPD. COPD displays distinct inflammaging features, including increased cellular senescence and oxidative stress, stem cell exhaustion, alterations in the extracellular matrix, reduced levels of endogenous anti-inflammaging molecules, and reduced autophagy. Given that COPD and inflammaging share similar general features, it is very important to identify the specific mechanisms of inflammaging, which involve oxidative stress, inflammation and lung mesenchymal stem cell function in the development of COPD, especially in elderly COPD patients. In this review, we highlight the studies relevant to COPD progression, and focus on mechanisms associated with inflammaging.

Bone marrow mesenchymal stem cells enhance autophagy and help protect cells under hypoxic and retinal detachment conditions

Our study aimed to evaluate the protective role and mechanisms of bone marrow mesenchymal stem cells (BMSCs) in hypoxic photoreceptors and experimental retinal detachment. The cellular morphology, viability, apoptosis and autophagy of hypoxic 661w cells and cells cocultured with BMSCs were analysed. In retinal detachment model, BMSCs were intraocularly transplanted, and then, the retinal morphology, outer nuclear layer (ONL) thickness and rhodopsin expression were studied as well as apoptosis and autophagy of the retinal cells. The hypoxia‐induced apoptosis of 661w cells obviously increased together with autophagy levels increasing and peaking at 8 hours after hypoxia. Upon coculturing with BMSCs, hypoxic 661w cells had a better morphology and fewer apoptosis. After autophagy was inhibited, the apoptotic 661w cells under the hypoxia increased, and the cell viability was reduced, even in the presence of transplanted BMSCs. In retina‐detached eyes transplanted with BMSCs, the retinal ONL thickness was closer to that of the normal retina. After transplantation, apoptosis decreased significantly and retinal autophagy was activated in the BMSC‐treated retinas. Increased autophagy in the early stage could facilitate the survival of 661w cells under hypoxic stress. Coculturing with BMSCs protects 661w cells from hypoxic damage, possibly due to autophagy activation. In retinal detachment models, BMSC transplantation can significantly reduce photoreceptor cell death and preserve retinal structure. The capacity of BMSCs to reduce retinal cell apoptosis and to initiate autophagy shortly after transplantation may facilitate the survival of retinal cells in the low‐oxygen and nutrition‐restricted milieu after retinal detachment.

Autophagy: a potential key contributor to the therapeutic action of mesenchymal stem cells

Macroautophagy/autophagy occurs at basal levels in all eukaryotic cells and plays an important role in maintaining bio-energetic homeostasis through the control of molecule degradation and organelle turnover. It can be induced by environmental conditions such as starvation, and is deregulated in many diseases including autoimmune diseases, neurodegenerative disorders, and cancer. Interestingly, the modulation of autophagy in mesenchymal stem cells (MSCs) represents a possible mechanism which, affecting MSC properties, may have an impact on their regenerative, therapeutic potential. Furthermore, the ability of MSCs to modulate autophagy of cells in injured tissues/organs has been recently proposed to be involved in the regeneration of damaged tissues and organs. In particular, MSCs can affect autophagy in immune cells involved in injury-induced inflammation reducing their survival, proliferation, and function and favoring the resolution of inflammation. In addition, MSCs can affect autophagy in endogenous adult or progenitor cells, promoting their survival, proliferation and differentiation supporting the restoration of functional tissue. This review provides, for the first time, an overview of the studies which highlight a possible link between the therapeutic properties of MSCs and their ability to modulate autophagy, and it summarizes examples of disorders where these therapeutic properties have been correlated with such modulation. A better elucidation of the mechanism(s) through which MSCs can modulate the autophagy of target cells and how autophagy can affect MSCs therapeutic properties, can provide a wider perspective for the clinical application of MSCs in the treatment of many diseases.Abbreviations: 3-MA: 3-methyladenine; AD: Alzheimer disease; ATG: autophagy-related; BECN1: beclin 1; BM: bone marrow; CD: cluster of differentiation; EAE: experimental autoimmune encephalomyelitis; IL: interleukin; INF: interferon; LAP: LC3-associated phagocytosis; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MSCs: mesenchymal stem cells; MTOR: mechanistic target of rapamycin kinase; PD: Parkinson disease; PtdIns3K: class III phosphatidylinositol 3-kinase; ROS: reactive oxygen species; SLE: systemic lupus erythematosus; SQSTM1: sequestosome 1; TBI: traumatic brain injury; TGF: transforming growth factor; TNF: tumor necrosis factor.

Human mesenchymal stem cells-derived conditioned medium inhibits hypoxia-induced death of neonatal porcine islets by inducing autophagy

BACKGROUND

The dysfunction of islet grafts is generally attributed to hypoxia-induced damage. Mesenchymal stem cells (MSCs) are currently thought to effectively protect cells from various risk factors via regulating autophagy. In our study, we investigated if human umbilical cord-derived MSCs could ameliorate hypoxia-induced apoptosis in porcine islets by modulating autophagy, and we explored the underlying mechanisms.

METHODS

Neonatal porcine islet cell clusters (NICCs) were cultured with human umbilical cord-derived MSC conditioned medium (huc-MSC-CM) and RPMI-1640 medium (control) under hypoxic conditions (1% O₂ ) in vitro. NICCs were treated with 3-methyladenine (3-MA) and chloroquine (CQ) to examine the role of huc-MSC-CM in regulating autophagy. Finally, the levels of several cytokines secreted by huc-MSCs were detected by ELISAs, and the corresponding inhibitors were applied to investigate which cytokine mediates the protective effects of huc-MSC-CM. The effects of huc-MSC-CM on NICCs viability and autophagy were examined using AO/PI staining, flow cytometry analysis, transmission electron microscopy (TEM) and confocal fluorescence microscopy analysis. The insulin secretion of NICCs was tested with an insulin immunoradiometric assay kit.

RESULTS

Compared to the control, the huc-MSC-CM treatment improved the viability of NICCs, inhibited apoptosis, increased autophagic activity and the levels of PI3K class III and phosphorylated Akt, while the ratio of phosphorylated mTOR/mTOR was reduced. These changes were reversed by CQ and 3-MA treatments. High concentrations of IL-6 were detected in hu-MSC-CM. Furthermore, recombinant IL-6 pre-treatment exerted similar effects as huc-MSC-CM, and these effects were reversed by a specific inhibitor of IL-6 (Sarilumab).

CONCLUSIONS

Our results demonstrated that huc-MSC-CM improved islet viability and function by increasing autophagy through the PI3K/Akt/mTOR pathway under hypoxic conditions. Additionally, IL-6 plays an important role in the function of huc-MSC-CM.

Betulinic Acid Enhances the Viability of Random-Pattern Skin Flaps by Activating Autophagy

Random-pattern skin flap replantation is commonly used to repair skin defects during plastic and reconstructive surgery. However, flap necrosis due to ischemia and ischemia-reperfusion injury limits clinical applications. Betulinic acid, a plant-derived pentacyclic triterpene, may facilitate flap survival. In the present study, the effects of betulinic acid on flap survival and the underlying mechanisms were assessed. Fifty-four mice with a dorsal random flap model were randomly divided into the control, betulinic acid group, and the betulinic acid + 3-methyladenine group. These groups were treated with dimethyl sulfoxide, betulinic acid, and betulinic acid plus 3-methyladenine, respectively. Flap tissues were acquired on postoperative day 7 to assess angiogenesis, apoptosis, oxidative stress, and autophagy. Betulinic acid promoted survival of the skin flap area, reduced tissue edema, and enhanced the number of microvessels. It also enhanced angiogenesis, attenuated apoptosis, alleviated oxidative stress, and activated autophagy. However, its effects on flap viability and angiogenesis, apoptosis, and oxidative stress were reversed by the autophagy inhibitor 3-methyladenine. Our findings reveal that betulinic acid improves survival of random-pattern skin flaps by promoting angiogenesis, dampening apoptosis, and alleviating oxidative stress, which mediates activation of autophagy.

Mesenchymal stem cell-derived extracellular vesicles improve the molecular phenotype of isolated rat lungs during ischemia/reperfusion injury

BACKGROUND

Lung ischemia/reperfusion (IR) injury contributes to the development of severe complications in patients undergoing transplantation. Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) exert beneficial actions comparable to those of MSCs without the risks of the cell-based strategy. This research investigated EV effects during IR injury in isolated rat lungs.

METHODS

An established model of 180-minutes ex vivo lung perfusion (EVLP) was used. At 60 minutes EVs (n = 5) or saline (n = 5) were administered. Parallel experiments used labeled EVs to determine EV biodistribution (n = 4). Perfusate samples were collected to perform gas analysis and to assess the concentration of nitric oxide (NO), hyaluronan (HA), inflammatory mediators, and leukocytes. Lung biopsies were taken at 180 minutes to evaluate HA, adenosine triphosphate (ATP), gene expression, and histology.

RESULTS

Compared with untreated lungs, EV-treated organs showed decreased vascular resistance and a rise of perfusate NO metabolites. EVs prevented the reduction in pulmonary ATP caused by IR. Increased medium-high-molecular-weight HA was detected in the perfusate and in the lung tissue of the IR + EV group. Significant differences in cell count on perfusate and tissue samples, together with induction of transcription and synthesis of chemokines, suggested EV-dependent modulation of leukocyte recruitment. EVs upregulated genes involved in the resolution of inflammation and oxidative stress. Biodistribution analysis showed that EVs were retained in the lung tissue and internalized within pulmonary cells.

CONCLUSIONS

This study shows multiple novel EV influences on pulmonary energetics, tissue integrity, and gene expression during IR. The use of cell-free therapies during EVLP could constitute a valuable strategy for reconditioning and repair of injured lungs before transplantation.

Human umbilical cord-derived mesenchymal stem cells enhanced HK-2 cell autophagy through MicroRNA-145 by inhibiting the PI3K/AKT/mTOR signaling pathway

Recent studies have shown that autophagy exhibits a protective role in acute kidney injury (AKI), and the accumulation of advanced oxidation protein products (AOPP) participates in the progression of kidney diseases. Our previous study indicated that AOPP induced injury in renal tubular epithelial cells (RTECs) through autophagy inhibition. Besides, we found that human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) enhanced autophagy in AOPP-treated RTECs, but the underlying mechanism remains unclear. We regulated microRNA-145 (miR-145) expression in HK-2 cells (a cell line of RTECs), or co-cultured hUC-MSCs with HK-2 cells and studied the autophagic activity in HK-2 cells to explore the underlying mechanism. Our data demonstrated that upregulated miR-145 increased LC3 II and Beclin 1 levels, decreased p62 level, three autophagy related proteins, inhibited the phosphorylation of PI3K/AKT/mTOR, and increased LC3B-positive staining and the autophagosome number. Furthermore, hUC-MSCs enhanced autophagy and inhibited phosphorylation of PI3K/AKT/mTOR in AOPP-treated HK-2 cells, which was then partially rescued using miR-145 knockdown in the hUC-MSCs co-culture system. In conclusion, our study showed that hUC-MSCs enhanced autophagy in AOPP-treated HK-2 cells mediated by miR-145 via inhibition of the PI3K/AKT/mTOR pathway, which indicated that hUC-MSCs might serve as a prospective therapy for AKI.

Bone marrow mesenchymal stem cell transplantation exerts neuroprotective effects following cerebral ischemia/reperfusion injury by inhibiting autophagy via the PI3K/Akt pathway

Although cerebral ischemia itself is associated with a high rate of disability, secondary cerebral ischemia/reperfusion (I/R) injury following recanalization is associated with much more severe outcomes. The mechanisms underlying cerebral I/R injury are complex, involving neuronal death caused by apoptosis and autophagy. Autophagy is critical for cell survival and plays an important role in the pathogenesis of cerebral I/R injury. Research has indicated that transplantation of bone marrow mesenchymal stem cells (BMSCs) is effective in repairing and reconstructing brain tissue, and that this effect may be associated with the regulation of autophagy. To explore this hypothesis, we intravenously transplanted BMSCs into a rat model of cerebral I/R injury (middle cerebral artery occlusion [MCAO]). Our results indicated that BMSCs transplantation promoted behavioral recovery, reduced cerebral infarction volume, and decreased the number of apoptotic cells in rats exposed to cerebral I/R injury. Moreover, this effect was associated with reduced expression of the autophagy-associated proteins microtubule-associated protein 1 light chain 3 (LC3) and Beclin-1. Furthermore, BMSCs remarkably increased the expression of p-Akt and p-mTOR following cerebral I/R injury. Expression of LC3 also increased when the PI3K pathway was blocked using LY294002. In summary, our results indicated that the protective effects of BMSCs in cerebral I/R injury may be associated with the inhibition of autophagy via the activation of the PI3K/Akt/mTOR signaling pathway.

Curcumin Attenuates gp120-Induced Microglial Inflammation by Inhibiting Autophagy via the PI3K Pathway

Microglial inflammation plays an essential role in the pathogenesis of HIV-associated neurocognitive disorders. A previous study indicated that curcumin relieved microglial inflammatory responses. However, the mechanism of this process remained unclear. Autophagy is a lysosome-mediated cell content-dependent degradation pathway, and uncontrolled autophagy leads to enhanced inflammation. The role of autophagy in curcumin-attenuating BV2 cell inflammation caused by gp120 was investigated with or without pretreatment with the autophagy inhibitor 3-MA and blockers of NF-κB, IKK, AKT, and PI3K, and we then detected the production of the inflammatory mediators monocyte chemoattractant protein-1 (MCP-1) and IL17 using ELISA, and autophagy markers ATG5 and LC3 II by Western Blot. The autophagic flux was observed by transuding mRFP-GFP-LC3 adenovirus. The effect of the blockers on gp120-induced BV2 cells was examined by the expression of p-AKT, p-IKK, NF-κB, and p65 in the nuclei and LC3 II and ATG5. gp120 promoted the expression of MCP-1 and IL-17, enhanced autophagic flux, and up-regulated the expression of LC3 II and ATG5, while the autophagy inhibitor 3-MA down-regulated the phenomena above. Curcumin has similar effects with 3-MA, in which curcumin inhibited NF-κB by preventing the translocation of NF-κB p65. Curcumin also inhibited the phosphorylation of p-PI3K, p-AKT, and p-IKK, which leads to down-regulation of NF-κB. Curcumin reduced autophagy via PI3K/AKT/IKK/NF-κB, thereby reducing BV2 cellular inflammation induced by gp120.

RAB26-dependent autophagy protects adherens junctional integrity in acute lung injury

Microvascular barrier dysfunction is the central pathophysiological feature of acute lung injury (ALI). RAB26 is a newly identified small GTPase involved in the regulation of endothelial cell (EC) permeability. However, the mechanism behind this protection has not been clearly elucidated. Here we found that RAB26 promoted the integrity of adherens junctions (AJs) in a macroautophagy/autophagy-dependent manner in ALI. RAB26 is frequently downregulated in mouse lungs after LPS treatment. Mice lacking Rab26 exhibited phosphorylated SRC expression and increased CDH5/VE-cadherin phosphorylation, leading to AJ destruction. rab26-null mice showed further aggravation of the effects of endotoxin insult on lung vascular permeability and water content. Depletion of RAB26 resulted in upregulation of phosphorylated SRC, enhancement of CDH5 phosphorylation, and aggravation of CDH5 internalization, thereby weakening AJ integrity and endothelial barrier function in human pulmonary microvascular endothelial cells (HPMECs). RAB26 overexpression caused active interaction between SRC and the autophagy marker LC3-II and promoted degradation of phosphorylated SRC. Furthermore, RAB26 was involved in a direct and activation-dependent manner in autophagy induction through interaction with ATG16L1 in its GTP-bound form. These findings demonstrate that RAB26 exerts a protective effect on endothelial cell (EC) permeability, which is in part dependent on autophagic targeting of active SRC, and the resultant CDH5 dephosphorylation maintains AJ stabilization. Thus, RAB26-mediated autophagic targeting of phosphorylated SRC can maintain barrier integrity when flux through the RAB26-SRC pathway is protected. These findings suggest that activation of RAB26-SRC signaling provides a new therapeutic opportunity to prevent vascular leakage in ALI.

ABBREVIATIONS

AJs: adherens junctions; ALI: acute lung injury; ARDS: acute respiratory distress syndrome; ATG5: autophagy related 5; ATG12: autophagy related 12; ATG 16L1: autophagy related 16 like; 1 BALF: bronchoalveolar lavage fluidCQ: chloroquine; Ctrl: control; EC: endothelial cell; GFP: green fluorescent protein; HA-tagged; RAB26^WT: HA-tagged wild-type; RAB26  HA-tagged; RAB26^QL: HA-tagged; RAB26^Q123LHA-tagged; RAB26^NI: HA-tagged; RAB26^N177IHPMECs: human pulmonary microvascular endothelial cells; H&E: hematoxylin & eosin; IgG: immunoglobulin; GIF: immunofluorescence; IP: immunoprecipitationi;. p.: intraperitoneal; LPS: lipopolysaccharide; PBS: phosphate-buffered salinesi; RNA: small interfering;RNASQSTM1/p62, sequestosome; 1TBS: Tris-buffered saline; VEGF: vascular endothelial growth factor; WB: western blot; WT: wild-type.

Mesenchymal stem cells enhance autophagy of human intrahepatic biliary epithelial cells in vitro

Dysfunctional autophagy in intrahepatic biliary epithelial cells (IBECs) is the main mechanism underlying the pathogenesis of bile duct lesions in primary biliary cholangitis. Autophagy may be a key pathogenesis for aetiology of primary biliary cholangitis. Immunoblotting and immunofluorescence analyses were used for the evaluation of autophagy in human intrahepatic biliary epithelial cells (HiBECs) at various time points. Glycochenodeoxycholate (GCDC) induced autophagy in HiBECs; the ratio of microtubule-associated protein light chain 3-II/microtubule-associated protein light chain 3-I (LC3-II/LC3-I) expression markedly increased at 48 hours, and then declined. However, compared with cells treated with GCDC alone, the expression of LC3-II increased and the clearance of autophagosome enhanced in GCDC-treated cells cocultured with mesenchymal stem cells (MSCs). Furthermore, the level of phosphorylation of signal transducer and activator of transcription 3 (pSTAT3) decreased in HiBECs cocultured with MSCs relative to those cultured without MSCs. Following STAT3 silencing, decreased expression of phosphorylated eukaryotic initiation factor 2α was consistently observed. The present data suggest that mesenchymal stem cells may enhance autophagic flux of HiBECs through the inhibition of STAT3 activity.

SIGNIFICANCE PARAGRAPH

The present findings constitute the first report that human umbilical cord-derived MSCs enhance autophagic flux in HiBECs through a STAT3-dependent way: MSCs enhance the autophagic flux by increasing the formation of autophagosome and autolysosome in GCDC-treated HiBECs. MSCs decrease the STAT3 activity and the expression of eIF2α in GCDC-treated HiBECs; in addition, MSCs increase the expression of PKR. With STAT3 silencing, MSCs enhance neither the levels of LC3II nor the expression of PKR in GCDC-treated HiBECs.

BM‑MSCs protect against liver ischemia/reperfusion injury via HO‑1 mediated autophagy

Ischemia/reperfusion (I/R) injury is considered to be a contributing factor in liver injury following major hepatic resection or liver transplantation. Bone marrow mesenchymal stem cells (BM‑MSCs) have the potential to protect against liver I/R injury; however, the precise mechanisms have not been completely elucidated. Autophagy serves an important role in protecting against various injuries, including I/R injury. The present study aimed to determine the role of autophagy and its potential regulatory mechanism in BM‑MSC‑mediated protection against liver I/R injury in rats. The results demonstrated that BM‑MSCs mitigated I/R injury and enhanced autophagy in vivo. In addition, inhibition of autophagy by 3‑methyladenine reversed the positive effects of BM‑MSCs. Furthermore, heme oxygenase‑1 (HO‑1) expression was promoted by BM‑MSCs. Using zinc protoporphyrin IX to inhibit HO‑1 demonstrated that HO‑1 was important for the promotion of autophagy. In conclusion, the present study revealed that BM‑MSCs protected against liver I/R injury via the promotion of HO‑1‑mediated autophagy.

FGF21 attenuates hypoxia‑induced dysfunction and apoptosis in HPAECs through alleviating endoplasmic reticulum stress

Vascular endothelial apoptosis and dysfunction have a crucial role in triggering pathological vascular remodeling of hypoxia‑induced pulmonary arterial hypertension (PAH). Fibroblast growth factor (FGF)21, an endocrine regulator, has recently been reported to protect cardiac endothelial cells from damage and suppress inflammatory responses. In addition, FGF21 is reported to be involved in endoplasmic reticulum stress (ERS). Previous studies have suggested that ERS participates in the development of PAH, and attenuation of ERS could be an effective therapeutic strategy for the protection of pulmonary arteries. However, whether FGF21 has a protective function via suppression of ERS in pulmonary arterial endothelial cells in hypoxia remains unclear. The present study aimed to explore whether FGF21 could reduce the hypoxia‑induced apoptosis of human pulmonary arterial endothelial cells (HPAECs) and prevent endothelial dysfunction via the inhibition of ERS. HPAECs were divided into six groups: Normoxia, hypoxia, hypoxia plus FGF21, hypoxia plus salubrinal (an ERS inhibitor), hypoxia plus tunicamycin (an ERS agonist), and hypoxia plus tunicamycin plus FGF21. The endoplasmic reticulum ultrastructure in HPAECs was assessed by transmission electron microscopy, and proliferation and apoptosis were examined by cell counting kit‑8 and terminal deoxyribonucleotide transferase‑mediated dUTP nick end‑labelling assays, respectively. The expression levels of ERS‑related proteins, including binding immunoglobulin protein (BiP), protein kinase R‑like endoplasmic reticulum kinase (PERK), phosphorylated (p‑) PERK, transcription factor C/EBP homologous protein (CHOP), B‑cell lymphoma-2 (Bcl‑2) and caspase‑4 were detected by western blotting. Transwell migration chamber assays were performed, and the concentration of nitric oxide (NO)/endothelin‑1 (ET‑1) in the culture medium was determined to examine endothelial function. The results revealed that hypoxia increased the % of apoptotic cells and diminished the viability of HPAECs, accompanied by an upregulation of ERS‑dependent apoptosis by increasing the expression of the proapoptotic caspase‑4 and decreasing the antiapoptotic Bcl‑2. Additionally, hypoxia upregulated the expression of representative proteins in the PERK branch of ERS, including BiP, p‑PERK and CHOP, while it downregulated the expression of PERK. Furthermore, the secretion of NO/ET‑1 and the migration rate of HPAECs were downregulated under conditions of hypoxia. FGF21 significantly attenuated the hypoxia‑induced apoptosis and dysfunction of HPAECs through alleviating the aforementioned changes in ERS‑dependent signaling pathways. In conclusion, ERS may be a crucial mechanism in the hypoxia‑induced apoptosis and endothelial dysfunction of HPAECs. FGF21 may attenuate the hypoxia‑induced apoptosis and dysfunction of HPAECs through alleviating ERS, via the PERK/CHOP signaling pathway and inhibition of caspase‑4 expression.

Hepatic miR-125b inhibits insulin signaling pathway by targeting PIK3CD

Insulin resistance is often characterized as the most critical factor contributing to the development of (T2D) type 2 diabetes. MicroRNAs (miRNAs) are endogenous non-coding short single-stranded RNAs that function as negative regulators in many physiological and pathological processes. The objective of this study was to evaluate the roles of miR-125b in the regulation of insulin sensitivity in hepatocytes. We found that hepatic miR-125b levels were significantly increased in the patients with type 2 diabetes, high fat diet (HFD) mice, ob/ob and db/db mice. In vitro, miR-125b was also significantly up-regulated in tumor necrosis factor-alpha- (TNF-α) and glucosamine-induced insulin resistance conditions. Furthermore, miR-125b overexpression impaired the insulin signaling pathway in HepG2 cells, L02c cells, and primary hepatocytes. Inhibition of miR-125b improved insulin sensitivity, especially in insulin-resistant cells induced by either TNF-α or glucosamine. We demonstrated that miR-125b targeted the 3'-untranslated region (3'-UTR) of phosphoinositide 3-kinase catalytic subunit delta (PIK3CD) mRNA. The hepatic PIK3CD protein levels were markedly decreased in patients with type 2 diabetes, HFD, ob/ob, and db/db mice. Inhibition of PIK3CD markedly attenuated the improvement of insulin sensitivity induced by miR-125b inhibitors. More importantly, overexpressing miR-125b in mice causes insulin resistance and impairs glucose homeostasis. Together, these findings indicate that miR-125b inhibits insulin sensitivity by targeting PIK3CD in hepatocytes, supporting hepatic miR-125b, or PIK3CD are potential therapeutic target of insulin resistance.

The promise of mesenchymal stem cell therapy for acute respiratory distress syndrome

This review describes the current state of the science on mesenchymal stem cell (MSC) treatment for acute lung injury (ALI). The general characteristics, regenerative potential, and mechanism of action of MSCs are first presented. Next, particular emphasis is placed on the application of MSCs for the treatment of acute respiratory distress syndrome (ARDS) in preclinical and clinical studies. Finally, we discuss current challenges and future directions in the field presented from a clinician-researcher perspective. The objective of this work is to provide the readership with a current review of the literature discussing the hurdles and overall promise of MSCs as therapeutic interventions for the treatment of ARDS.

Autophagy: A new treatment strategy for MSC-based therapy in acute kidney injury (Review)

Acute kidney injury (AKI) is a common and serious medical condition associated with poor health outcomes. Autophagy is a conserved multistep pathway that serves a major role in many biological processes and diseases. Recent studies have demonstrated that autophagy is induced in proximal tubular cells during AKI. Autophagy serves a pro‑survival or pro‑death role under certain conditions. Furthermore, mesenchymal stem cells (MSCs) have therapeutic potential in the repair of renal injury. This review summarizes the recent progress on the role of autophagy in AKI and MSCs‑based therapy for AKI. Further research is expected to prevent and treat acute kidney injury.

ATG101 Single-Stranded Antisense RNA-Loaded Triangular DNA Nanoparticles Control Human Pulmonary Endothelial Growth via Regulation of Cell Macroautophagy

Autophagy plays a key role in pulmonary vascular remodeling via regulation of apoptosis and hyperproliferation of pulmonary arterial endothelial cells, which are the subject of increased attention. Autophagy-related 101 (ATG101) is an essential gene for the initiation of autophagy. Although the structure of ATG101 has been well-characterized, its exact biological function in autophagy is still unknown. In this study, an ATG101 single-stranded antisense RNA-loaded DNA triangular nanoparticle (ssATG101-TNP) is constructed to knock down the ATG101 gene expression. ssATG101-TNP can be effectively transfected into human pulmonary arterial endothelial cells (HPAECs) in time- and dose-dependent manners. Knockdown of ATG101 promotes cell apoptosis as well as inhibits cell autophagy and proliferation with hypoxic stimulation. Additionally, the hedgehog/Gli signal pathway is involved in ATG101-mediated macroautophagy and HPAEC proliferation. This study found that ATG101, an important member of the autophagy gene family, can regulate cell macroautophagy, apoptosis, and growth in HPAECs. ssATG101-TNP is demonstrated to be a nontoxic, highly efficient, gene-delivery vehicle for HPAECs. These findings also suggest that ATG101 might be a potential therapeutic target in diseases involving endothelial injury.

Mechanisms of lung ischemia-reperfusion injury

PURPOSE OF REVIEW

Lungs are extremely susceptible to injury, and despite advances in surgical management and immunosuppression, outcomes for lung transplantation are the worst of any solid organ transplant. The success of lung transplantation is limited by high rates of primary graft dysfunction because of ischemia-reperfusion injury characterized by robust inflammation, alveolar damage, and vascular permeability. This review will summarize major mechanisms of lung ischemia-reperfusion injury with a focus on the most recent findings in this area.

RECENT FINDINGS

Over the past 18 months, numerous studies have described strategies to limit lung ischemia-reperfusion injury in experimental settings, which often reveal mechanistic insight. Many of these strategies involved the use of various antioxidants, anti-inflammatory agents, mesenchymal stem cells, and ventilation with gaseous molecules. Further advancements have been achieved in understanding mechanisms of innate immune cell activation, neutrophil infiltration, endothelial barrier dysfunction, and oxidative stress responses.

SUMMARY

Methods for prevention of primary graft dysfunction after lung transplant are urgently needed, and understanding mechanisms of ischemia-reperfusion injury is critical for the development of novel and effective therapeutic approaches. In doing so, both acute and chronic outcomes of lung transplant recipients will be significantly improved.

The Expression of Dectin-1, Irak1 and Rip2 During the Host Response to Aspergillus fumigatus

BACKGROUND

C-type lectin receptors (CLRs), Toll-like receptors (TLRs), and Nod-like receptors (NLRs) have the ability to recognize Aspergillus fumigatus (A. fumigates) and induce innate immune response. Dectin-1 is a well-described CLR, while interleukin-1 receptor-associated kinase 1 (Irak1) and receptor-interacting protein 2 (Rip2) are pivotal adaptor proteins of TLRs and NLRs signaling pathways, respectively.

OBJECTIVES

Our primary aim is to elucidate whether Dectin-1 regulates the expression of Irak1 and Rip2, and confirm that CLRs, TLRs, and NLRs pathways act synergistically in response to A. fumigatus infection.

METHODS

Pulmonary infection mouse models were established. Myeloid cells were differentiated in cell culture and examined by inverted microscopy, flow cytometry, and scanning electron microscopy. The relative mRNA levels were determined by qRT-PCR. The protein expression levels were determined by immunohistochemistry and Western blot.

RESULTS

The expression of Dectin-1, Irak1, Rip2, and phosphorylation level of nuclear factor (NF)-κB p65 were induced by conidia in immunocompetent mice, while their expression and phosphorylation level were inhibited in immunocompromised mice after the administration of conidia. Conidia increased the expression of Dectin-1, Irak1, and Rip2 in myeloid cells, while Dectin-1 silencing significantly reduced their expression.

CONCLUSION

Our findings demonstrate that Dectin-1, Irak1, and Rip2 are involved in response to A. fumigatus infection. Dectin-1 modulates the expression of Irak1 and Rip2. Additionally, these three signaling pathways are interconnected, and CLRs pathway plays a dominant role against A. fumigatus invasion.

Role of autophagy and its signaling pathways in ischemia/reperfusion injury

This study was conducted to investigate the mechanism of autophagy and its signaling pathways in ischemia/reperfusion injury (IRI). Pulmonary microvascular endothelial cells (PMVECs) were used to construct I/R models. The cells were then treated with autophagy inhibitor 3-MA and infected with adenovirus expressing Beclin 1-shRNA. The expression of CD31, LC3-II, Bcl-2, Bax, LC3-II, Beclin 1, AKT, p-AKT, AMPK and p-AMPK, apoptosis, cell viability and migration ability were determined. Over 95% isolated PMVECs were positive for CD31. The expression of LC3-II and Beclin 1 was up-regulated in I/R cells. 3-MA and Beclin 1 knockdown inhibited the expression of LC3-II and Beclin 1 and autophagosome formation. Autophagy induced by hypoxia was antagonistic against apoptosis, which increased after treatment with 3-MA and knockdown of Beclin 1. 3-MA and Beclin 1 knockdown downregulated and upregulated the expression of Bcl-2 and Bax, respectively. Apoptosis mediated by hypoxia and reperfusion-induced autophagy was reduced by 3-MA and Beclin-1 knockdown, which increased and reduced the expression of Bcl-2 and Bax, respectively, leading to significant decreased Bax/Bcl-2 ratio. In these cells, expression of p-AKT, p-AMPK and p-mTOR was up-regulated. After treatment with 3-MA and Beclin 1 knockdown, expression of p-AKT and p-AMPK was significantly reduced.

Regulation on Toll-like Receptor 4 and Cell Barrier Function by Rab26 siRNA-loaded DNA Nanovector in Pulmonary Microvascular Endothelial Cells

The small GTPase Rab26 is involved in multiple processes, such as vesicle-mediated secretion and autophagy. However, the mechanisms and functions of Rab26 in the human pulmonary microvascular endothelial cells (HPMVECs) are not clear. In this study, we thoroughly investigated the role and novel mechanism of Rab26 in permeability and apoptosis of HPMVECs using a self-assembled Rab26 siRNA loaded DNA Y-motif nanoparticle (siRab26-DYM) and Rab26 adenovirus. We found that siRab26-DYM could be efficiently transfected into HPMVECs in a time- and dose-dependent manner. Importantly, the siRab26-DYM nanovector markedly aggravated the LPS-induced apoptosis and hyper-permeability of HPMVECs by promoting the nuclear translocation of Foxo1, and subsequent activation of Toll-like receptor 4 (TLR4) signal pathway. Overexpression of Rab26 by Rab26 adenoviruses partially inactivated LPS-induced TLR4 signaling pathway, suppressed the cell apoptosis and attenuated the hyperpermeability of HPMVECs. These results suggest that the permeability and apoptosis of HPMVECs can be modulated by manipulating Rab26 derived TLR4 signaling pathway, and that Rab26 can be potential therapeutic target for the treatment of vascular diseases related to endothelial barrier functions.