Modulating putative endothelial progenitor cells for the treatment of endothelial dysfunction and cardiovascular complications in diabetes

Tilianin attenuates inflammasome activation in endothelial progenitor cells to mitigate myocardial ischemia-reperfusion injury

Tilianin (TIL), a bioactive component derived from Dracocephalum Moldavica L., has been recognized for its anti-inflammatory properties. However, its effects on the Nlrp3 inflammasome within endothelial progenitor cells (EPCs) during myocardial ischemia-reperfusion injury (MIRI) remain unexplored. This study aimed to elucidate the role of TIL in modulating Nlrp3 inflammasome activation under MIRI conditions. A mouse model of MIRI was established to assess the therapeutic potential of TIL. EPCs treated with TIL at concentrations of 5, 10, and 20 μM were administered into the myocardium before reperfusion. Additionally, the cardioprotective effects of TIL were further examined by pre-treating EPCs with the compound before exposing them to hypoxia/reoxygenation (H/R) using cardiomyocyte supernatants. The impact on Nlrp3 inflammasome was assessed through western blotting, immunofluorescence, and ELISA. Our results showed that TIL concentration-dependently inhibited Nlrp3 inflammasome-related protein levels,and inhibited Asc oligomerization and Asc-Speck complex formation in EPCs, resulting in improved the migratory capacity and vascular structure formation of EPCs. In addition, TIL-treated EPCs significantly attenuated I/R injury and improved cardiac function. These results suggest that TIL ameliorates the inflammatory response in EPCs by suppressing Nlrp3 inflammasome activation, thereby facilitating neovascularization in the myocardium and conferring protection against MIRI. The study provides valuable insights into the potential of TIL as a therapeutic agent for cardiovascular diseases linked to ischemia-reperfusion injury.

Liraglutide ameliorates high glucose-induced vascular endothelial injury through TRIB3/NF-κB signaling pathway

As one of the most commonly used antidiabetic medications clinically, liraglutide is involved in the protection of vascular endothelium, and whether it can relieve high glucose-induced vascular endothelial damage was unknown. This study aims to address the response of liraglutide (LIRA) on human umbilical vein endothelial cells, as well as to elucidate its possible underlying mechanism. We established a vascular endothelial cell injury model by exposing human umbilical vein endothelial cells (HUVECs) to high glucose, and used LIRA pretreatment before HG treatment to address the endothelial protective effect of LIRA. Our results suggest that LIRA prevented HG-induced HUVEC apoptosis, oxidative stress, inflammasome activation, and pyroptosis. Furthermore, silencing of tribbles homolog 3 (TRIB3) could markedly reduce HG-induced HUVEC apoptosis, ROS level, the expressions of TXNIP, cleaved caspase3, NLRP3, and caspase1, indicating TRIB3 inhibition protected HUVECs against HG-induced vascular endothelial injury. In addition, LIRA restrained NF-κB/IκB-α signaling pathway activation in HUVECs. Thus, LIRA appears to mitigate HG-induced apoptosis, oxidative stress, inflammasome activation, and pyroptosis in HUVECs via regulating the TRIB3/NF-κB/IκB-α signaling pathway. Our study provides new insight into the mechanisms underlying the protective activity of LIRA against the vascular endothelial injury in diabetic vascular complication.

Enhancing endothelial colony-forming cells for treating diabetic vascular complications: challenges and clinical prospects

Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia, leading to various vascular complications. Accumulating evidence indicates that endothelial colony-forming cells (ECFCs) have attractive prospects for repairing and restoring blood vessels. Thus, ECFCs may be a novel therapeutic option for diabetic patients with vascular complications who require revascularization therapy. However, it has been reported that the function of ECFCs is impaired in DM, which poses challenges for the autologous transplantation of ECFCs. In this review, we summarize the molecular mechanisms that may be responsible for ECFC dysfunction and discuss potential strategies for improving the therapeutic efficacy of ECFCs derived from patients with DM. Finally, we discuss barriers to the use of ECFCs in human studies in light of the fact that there are no published reports using these cells in humans.

Research Advances in Stem Cell Therapy for Erectile Dysfunction

Erectile dysfunction (ED) is a common clinical condition that mainly affects men aged over 40 years. Various causes contribute to the progression of ED, including pelvic nerve injury, diabetes, metabolic syndrome, age, Peyronie's disease, smoking, and psychological disorders. Current treatments for ED are limited to symptom relief and do not address the root cause. Stem cells, with their powerful ability to proliferate and differentiate, are a promising approach for the treatment of male ED and are gradually gaining widespread attention. Current uses for treating ED have been studied primarily in experimental animals, with most studies observing improvements in erectile quality as well as improvements in erectile tissue. However, research on stem cell therapy for human ED is still limited. This article summarizes the recent literature on basic stem cell research on ED, including cavernous nerve injury, aging, diabetes, and sclerosing penile disease, and describes mechanisms of action and therapeutic effects of various stem cell therapies in experimental animals. Stem cells are also believed to interact with host tissue in a paracrine manner, and improved function can be supported through both implantation and paracrine factors. To date, stem cells have shown some preliminary promising results in animal and human models of ED.

The bone marrow endothelial progenitor cell response to septic infection

Early increase in the level of endothelial progenitor cells (EPCs) in the systemic circulation occurs in patients with septic infection/sepsis. The significance and underlying mechanisms of this response remain unclear. This study investigated the bone marrow EPC response in adult mice with septic infection induced by intravenous injection (i.v.) of Escherichia coli. For in vitro experiments, sorted marrow stem/progenitor cells (SPCs) including lineage(lin)-stem cell factor receptor (c-kit)+stem cell antigen-1 (Sca-1)-, lin-c-kit+, and lin- cells were cultured with or without lipopolysaccharides (LPSs) and recombinant murine vascular endothelial growth factor (VEGF) in the absence and presence of anti-Sca-1 crosslinking antibodies. In a separate set of experiments, marrow lin-c-kit+ cells from green fluorescence protein (GFP)+ mice, i.v. challenged with heat-inactivated E. coli or saline for 24 h, were subcutaneously implanted in Matrigel plugs for 5 weeks. Marrow lin-c-kit+ cells from Sca-1 knockout (KO) mice challenged with heat-inactivated E. coli for 24 h were cultured in the Matrigel medium for 8 weeks. The marrow pool of EPCs bearing the lin-c-kit+Sca-1+VEGF receptor 2 (VEGFR2)+ (LKS VEGFR2+) and LKS CD133+VEGFR2+ surface markers expanded rapidly following septic infection, which was supported by both proliferative activation and phenotypic conversion of marrow stem/progenitor cells. Increase in marrow EPCs and their reprogramming for enhancing angiogenic activity correlated with cell-marked upregulation of Sca-1 expression. Sca-1 was coupled with Ras-related C3 botulinum toxin substrate 2 (Rac2) in signaling the marrow EPC response. Septic infection caused a substantial increase in plasma levels of IFN-γ, VEGF, G-CSF, and SDF-1. The early increase in circulating EPCs was accompanied by their active homing and incorporation into pulmonary microvasculature. These results demonstrate that the marrow EPC response is a critical component of the host defense system. Sca-1 signaling plays a pivotal role in the regulation of EPC response in mice with septic infection.

Dapagliflozin alleviates high glucose-induced injury of endothelial cells via inducing autophagy

Hyperglycaemia is a key factor in the progression of diabetes complications. Dapagliflozin (DAPA), a new type of hypoglycaemic agent, has been shown to play an important role in anti-apoptotic, anti-inflammatory and antioxidant activities. Previous studies have demonstrated an endothelial protective effect of DAPA, but the underlying mechanism was still unclear. Autophagy is a homeostatic cellular mechanism that circulates unfolded proteins and damaged organelles through lysosomal dependent degradation. In this study, we aimed to investigate whether DAPA plays a protective role against high glucose (HG)-induced endothelial injury through regulating autophagy. The results showed that DAPA treatment resulted in increased cell viability. Additionally, DAPA treatment decreased interleukin (IL)-1β, IL-6, and tumour necrosis factor-α levels in endothelial cells subjected to HG conditions. We observed that HG inhibited autophagy, and DAPA increased the autophagy level by inhibiting the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signalling pathway. Chloroquine reversed all of these beneficial effects as an autophagy inhibitor. In summary, the endothelial protective effect of DAPA in HG can be attributed in part to its role in activating of autophagy via the AKT/mTOR signalling pathway. Therefore, suggesting that the activation of autophagy by DAPA may be a novel target for the treatment of HG-induced endothelial cell injury.

Retinoic acid signaling in development and differentiation commitment and its regulatory topology

Retinoic acid (RA), the derivative of vitamin A/retinol, is a signaling molecule with important implications in health and disease. It is a well-known developmental morphogen that functions mainly through the transcriptional activity of nuclear RA receptors (RARs) and, uncommonly, through other nuclear receptors, including peroxisome proliferator-activated receptors. Intracellular RA is under spatiotemporally fine-tuned regulation by synthesis and degradation processes catalyzed by retinaldehyde dehydrogenases and P450 family enzymes, respectively. In addition to dictating the transcription architecture, RA also impinges on cell functioning through non-genomic mechanisms independent of RAR transcriptional activity. Although RA-based differentiation therapy has achieved impressive success in the treatment of hematologic malignancies, RA also has pro-tumor activity. Here, we highlight the relevance of RA signaling in cell-fate determination, neurogenesis, visual function, inflammatory responses and gametogenesis commitment. Genetic and post-translational modifications of RAR are also discussed. A better understanding of RA signaling will foster the development of precision medicine to improve the defects caused by deregulated RA signaling.

Downregulated calmodulin expression contributes to endothelial cell impairment in diabetes

Endothelial dysfunction, a central hallmark of cardiovascular pathogenesis in diabetes mellitus, is characterized by impaired endothelial nitric oxide synthase (eNOS) and NO bioavailability. However, the underlying mechanisms remain unclear. Here in this study, we aimed to identify the role of calmodulin (CaM) in diabetic eNOS dysfunction. Human umbilical vein endothelial cells and murine endothelial progenitor cells (EPCs) treated with high glucose (HG) exhibited downregulated CaM mRNA/protein and vascular endothelial growth factor (VEGF) expression with impeded eNOS phosphorylation and cell migration/tube formation. These perturbations were reduplicated in CALM1-knockdown cells but prevented in CALM1-overexpressing cells. EPCs from type 2 diabetes animals behaved similarly to HG-treated normal EPCs, which could be rescued by CALM1-gene transduction. Consistently, diabetic animals displayed impaired eNOS phosphorylation, endothelium-dependent dilation, and CaM expression in the aorta, as well as deficient physical interaction of CaM and eNOS in the gastrocnemius. Local CALM1 gene delivery into a diabetic mouse ischemic hindlimb improved the blunted limb blood perfusion and gastrocnemius angiogenesis, and foot injuries. Diabetic patients showed insufficient foot microvascular autoregulation, eNOS phosphorylation, and NO production with downregulated CaM expression in the arterial endothelium, and abnormal CALM1 transcription in genome-wide sequencing analysis. Therefore, our findings demonstrated that downregulated CaM expression is responsible for endothelium dysfunction and angiogenesis impairment in diabetes, and provided a novel mechanism and target to protect against diabetic endothelial injury.

The Impact of Modern Anti-Diabetic Treatment on Endothelial Progenitor Cells

Diabetes is one of the leading chronic diseases globally with a significant impact on mortality. This condition is associated with chronic microvascular and macrovascular complications caused by vascular damage. Recently, endothelial progenitor cells (EPCs) raised interest due to their regenerative properties. EPCs are mononuclear cells that are derived from different tissues. Circulating EPCs contribute to regenerating the vessel's intima and restoring vascular function. The ability of EPCs to repair vascular damage depends on their number and functionality. Diabetic patients have a decreased circulating EPC count and impaired EPC function. This may at least partially explain the increased risk of diabetic complications, including the increased cardiovascular risk in these patients. Recent studies have confirmed that many currently available drugs with proven cardiovascular benefits have beneficial effects on EPC count and function. Among these drugs are also medications used to treat different types of diabetes. This manuscript aims to critically review currently available evidence about the ways anti-diabetic treatment affects EPC biology and to provide a broader context considering cardiovascular complications. The therapies that will be discussed include lifestyle adjustments, metformin, sulphonylureas, gut glucosidase inhibitors, thiazolidinediones, dipeptidyl peptidase 4 inhibitors, glucagon-like peptide 1 receptor analogs, sodium-glucose transporter 2 inhibitors, and insulin.

Endothelial Progenitor Cells in Autoimmune Disorders

Circulating endothelial progenitor cells (EPCs) were first described in 1997 by Asahara et al. as "putative endothelial cells" from human peripheral blood. The study of endothelial progenitors is also intensifying in several pathologies associated with endothelial damage, including diabetes, myocardial infarction, sepsis, pulmonary arterial hypertension, obstructive bronchopneumopathy and transplantation. EPCs have been studied in several autoimmune diseases with endothelial involvement such as systemic lupus erythematosus, thrombotic thrombocytopenic purpura, antineutrophil cytoplasmic antibodies, vasculitis, rheumatoid arthritis, Goujerot-Sjögren and antiphospholipid syndrome. Factors involved in endothelial damage are due to overexpression of pro-inflammatory cytokines and/or autoantibodies. Management of these pathologies, particularly the long-term use of glucocorticoids and methotrexate, promote atherosclerosis. A lack of standardized assessment of the number and function of EPCs represents a serious challenge for the use of EPCs as prognostic markers of cardiovascular diseases (CVD). The objective of this review was to describe EPCs, their properties and their involvement in several autoimmune diseases.

Omentin-1 enhances the inhibitory effect of endothelial progenitor cells on neointimal hyperplasia by inhibiting the p38 MAPK/CREB pathway

AIMS

Endothelial progenitor cells (EPCs) play an important role in vascular repair. However, they are dysfunctional in the inflammatory microenvironment during restenosis. In this study, we investigated whether omentin-1, an anti-inflammatory factor, could reduce neointima formation after carotid artery injury (CAI) in rats by improving EPC functions that were damaged by inflammation and the underlying mechanisms.

MAIN METHODS

EPCs were transfected with adenoviral vectors expressing human omentin-1 or green fluorescent protein (GFP). Then, the rats received 2 × 106 EPCs expressing omentin-1 or GFP by tail vein injection directly after CAI and again 24 h later. Hematoxylin-eosin staining and immunohistochemistry were used for analyzing neointimal hyperplasia. Besides, EPCs were treated with omentin-1 and TNF-α to examine the underlying mechanism.

KEY FINDINGS

Our results showed that omentin-1 could significantly improve EPC functions, including proliferation, apoptosis and tube formation. Meanwhile, EPCs overexpressed with omentin-1 could significantly reduce neointimal hyperplasia and tumor necrosis factor-α (TNF-α) expression after CAI in rats. TNF-α could notably induce EPC dysfunction, which could be markedly reversed by omentin-1 through the inhibition of the p38 MAPK/CREB pathway. Furthermore, a p38 MAPK agonist (anisomycin) significantly abrogated the protective effects of omentin-1 on EPCs damaged by TNF-α.

SIGNIFICANCE

Our results indicated that genetically modifying EPC with omentin-1 could be an alternative strategy for the treatment of restenosis.

Fabrication of a protein-dextran conjugates formed oral nanoemulsion and its application to deliver the essential oil from Alpinia zerumbet Fructus

The injury of vascular endothelial cells caused by high glucose (HG) is one of the driving factors of vascular complications of diabetes. Oral administration is the most common route of administration for the treatment of diabetes and its vascular complications. Essential oil extracts from Chinese medicine possess potential therapeutic effects on vascular endothelial injury. However, low solubility and volatility of essential oils generally result in poor oral absorption. Development of nanocarriers for essential oils is a promising strategy to overcome the physiological barriers of oral absorption. In this study, a nanoemulsion composed of bovine serum albumin (BSA)-dextran sulfate (DS) conjugate and sodium deoxycholate (SD) was constructed. The nanoemulsions were verified with promoted oral absorption and prolonged circulation time. After the primary evaluation of the nanoemulsion, essential oil from Alpinia zerumbet Fructus (EOFAZ)-loaded nanoemulsion (denoted as EOFAZ@BD5/S) was prepared and characterized. Compared to the free EOFAZ, EOFAZ@BD5/S increased the protective effects on HG-induced HUVEC injury in vitro and ameliorative effects on the vascular endothelium disorder and tunica media fibroelastosis in a T2DM mouse model. Collectively, this study provides a nanoemulsion for the oral delivery of essential oils, which holds strong promise in the treatment of diabetes-induced vascular endothelial injury.

Icariin alleviates ferroptosis-related atherosclerosis by promoting autophagy in xo-LDL-induced vascular endothelial cell injury and atherosclerotic mice

Vascular endothelial cells (VECs) are located between the blood plasma and the vascular tissue, and the ferroptosis (iron-dependent programmed cell death) of VECs can lead to a range of cardiovascular diseases. Icariin is the main active ingredient of Epimedium brevicornum Maxim., which can improve endothelial cell dysfunction. In the present study, the protective effects of icariin on oxidised low-density lipoprotein (ox-LDL)-treated VECs and high-fat diet-fed Apolipoprotein E-deficient mice were investigated. Inflammatory fibrosis in tissues and inflammatory factors in serum and cell supernatants were detected, and mitochondrial membrane potential and the expression levels of ferroptosis-associated proteins were also detected. The results revealed that icariin reduced the endothelial atherosclerotic plaque area and collagen fibres in aortic sinus tissue, and increased the viability and mitochondrial membrane potential, whereas it reduced the reactive oxygen species levels of VECs. The nucleation of transcription factor EB (TFEB) and subsequent autophagy were negatively associated with ferroptosis in endothelial cells, and the more prominent the autophagy, the lower the levels of ferroptosis. Furthermore, by co-treating the cells with icariin and the two autophagy inhibitors, Bafilomycin A1 (blocking autophagosome and lysosome fusion) and 3-methyladenine (blocking autophagosome formation), respectively, the promoting effects of icariin on autophagy were found to be mediated through the process of autophagosome-lysosome fusion. In in vivo experiments, icariin reduced ferroptosis, alleviated atherosclerotic lesions and increased the rate of TFEB nucleation. Additionally, it was found that ARG304, THR308 and GLN311 were the optimal binding sites for the interaction between icariin and TFEB. Taken together, these results suggest that the fusion of autophagosomes and lysosomes promoted by icarrin enhances autophagy and thus reduces ferroptosis. Therefore, icariin may be a potential candidate for the prevention of ferroptosis of VECs and, thus, for the treatment of cardiovascular diseases.

Platelet-Derived Growth Factor-BB Priming Enhances Vasculogenic Capacity of Bone Marrow-Derived Endothelial Precursor Like Cells

BACKGROUND

Human endothelial progenitor cells (EPCs) were first identified in the peripheral blood and later in the cord blood and bone marrow (BM) with different vascularization capacity and different surface marker profiles. However, their identity and functional roles in neovascularization have not been clearly demonstrated in vivo and in vitro.

METHODS

Characterization of BM-EPC like cells were performed by fluorescence-activated cell sorting, immunofluorescence staining, enzyme-linked immunosorbent assay, Matrigel tube formation assay, and western blot analysis.

RESULTS

BM-EPC like cells were identified by selective adhesion to fibronectin and collagen from BM mononuclear cells, which generate fast-growing colonies with spindle morphology, express surface markers of CD105, vWF, UEA-I lectin binding, secrete HGF, VEGF, TGF-beta1 but can be distinguished from circulating EPC and endothelial cells by no expression of surface markers such as CD31, CD309, CD45, and CD34. These BM-EPC like cells shared many cell surface markers of BM-mesenchymal stem cells (MSC) but also can be distinguished by their vasculogenic property and other unique surface markers. Furthermore, the vasculogenic capacity of BM-EPC like cells were enhanced by co-culture of BM-MSC or PDGF-BB priming. PDGF-BB stimulated cell migration, proliferation, and secretion of laminin β-1, which was proposed as one of the mechanisms involved in the better vascularization of BM-EPC like cells.

CONCLUSION

PDGF-BB priming may be applied to improve the potency and function of BM-EPC like cells as vasculogenic cell therapy for the ischemic vascular repair.

Dapagliflozin restores diabetes-associated decline in vasculogenic capacity of endothelial progenitor cells via activating AMPK-mediated inhibition of inflammation and oxidative stress

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) provide added vascular protection beyond glucose lowering to patients with type 2 diabetes mellitus (T2DM). Endothelial progenitor cells (EPCs) are an important endogenous repair mechanism for diabetic vascular complications. Yet, whether SGLT2i protect vessels in diabetic patients by improving the function of EPCs remains to be elucidated. Here we enrolled Sixty-three T2DM patients and 60 healthy participants and 15 of T2DM group took dapagliflozin for 3 months. Retinal capillary density (RCD) was examined before and after meditation. Moreover, vasculogenic capacity of EPCs cocultured with or without dapagliflozin in vitro and in vivo (hind limb ischemia model) were assessed. Mechanically, genes related to inflammation/oxidative stress, and the AMPK signaling of EPCs were determined. Our results found T2DM demonstrated a declined RCD and a decreased number of circulating EPCs compared with healthy controls. Compared with the EPCs from healthy individuals, vasculogenic capacity of T2DM EPCs was significantly impaired, which could be restored by dapagliflozin meditation or dapagliflozin coculture. Increased expression of inflammation correlative genes and decreased anti-oxidative stress related genes expression were found in EPCs form T2DM, which were accompanied with reduced phosphorylation level of AMPK. Dapagliflozin treatment activated AMPK signaling, decreased the level of inflammation and oxidative stress, and rescued vasculogenic capacity of EPCs from T2DM. Furthermore, AMPK inhibitor pretreatment diminished the enhancement vasculogenic capacity of diabetic EPCs from dapagliflozin treatment. This study demonstrates for the first time that dapagliflozin restores vasculogenic capacity of EPCs via activating AMPK-mediated inhibition of inflammation and oxidative stress in T2DM.

In vitro and in vivo effect of novel GA-CSNPs loaded col-fibrin nanocomposite scaffold on diabetic wound healing

A non-healing wound is a common problem associated with diabetes mellitus. Chronic inflammation, challenging re-epithelization, unusual growth factors, and impaired angiogenesis are the multifactorial events that contribute to impaired wounds. Hence, in the present work, an innovative GA-CSNPs nanocomposite scaffold has been fabricated by integrating Gallic acid (GA) loaded chitosan nanoparticles (GA-CSNPs) into a genipin crosslinked collagen-fibrin (Col-fibrin) scaffold as wound dressing material. The in vitro RT-PCR study carried out using NIH/3T3 mouse fibroblast cells showed that treatment with GA-CSNPs nanocomposite scaffold aids in an upsurge in the expression of Col-I, III, and VEGF, which further supports the synthesis of extracellular matrix, increases neovascularization and development of the established vascular system. In vivo wound contraction study results revealed that diabetic wounds treated with GA-CSNPs nanocomposite scaffold show a faster rate of wound closure (p < .001), histopathology results showed accelerated fibroblast cell migration, reduction of the inflammatory cells, enhanced collagen along with hexosamine synthesis. In addition, immunohistochemistry results showed increased vascularization, a significant decrease in macrophage recruitment, and reduced expression of MMP-9 compared to the Col-fibrin scaffold and Control groups. Overall data suggest that the fabricated GA-CSNPs nanocomposite porous 3-D scaffold can be a hopeful therapeutic choice for diabetic wound management.

Lpar1-mediated Effects in Endothelial Progenitor Cells Are Crucial for Lung Repair in Acute Respiratory Distress Syndrome/Acute Lung Injury

Acute respiratory distress syndrome/acute lung injury (ARDS/ALI) involves acute respiratory failure characterized by vascular endothelial and lung alveolar epithelial injury. Endothelial progenitor cells (EPCs) can mediate vasculogenesis. However, the limitations of EPCs, such as low survival and differentiation, are believed to inhibit the effectiveness of autologous cell therapies. This study demonstrated that lysophosphatidic acid (LPA), a bioactive small molecule without immunogenicity, is involved in the survival and antiapoptotic effects in human umbilical cord mesenchymal stem cells. This study aimed to explore whether LPA improves the survival of EPCs, enhancing the cellular therapeutic efficacy in ARDS, and these results will expand the application of LPA in stem cells and regenerative medicine. LPA promoted the colony formation, proliferation, and migration of EPCs and upregulated the expression of vascular endothelial-derived growth factor (VEGF) in EPCs. LPA pretreatment of transplanted EPCs improved the therapeutic effect by increasing EPC numbers in the rat lungs. LPA enhanced EPC proliferation and migration through Lpar1 coupled to G_i/o and G_q/11, respectively. Activation of extracellular signal-related kinase 1/2, or ERK1/2, was related to LPA-induced EPC proliferation but not migration. LPA/Lpar1-mediated G_i/o protein was also shown to be involved in promoting VEGF expression and inhibiting IL-1α expression in EPCs. Low LPA concentrations are present after lung injury; thus, the restoration of LPA may promote endothelial cell homeostasis and lung repair in ARDS. Inhalation of LPA significantly promoted the homing of endogenous EPCs to the lung and reduced lung injury in both rats with LPS-induced ALI and Streptococcus pneumoniae-infected mice. Taken together, these data indicated that LPA/Lpar1-mediated effects in EPCs are involved in maintaining endothelial cell homeostasis and lung tissue repair under physiological conditions.

Transplantation of Endothelial Progenitor Cells: Summary and prospect

Endothelial Progenitor Cells (EPCs) are precursor cells of endothelial cells (ECs), which can differentiate into vascular ECs, protect from endothelial dysfunction and tissue ischemia, and reduce vascular hyperplasia. Due to these functions, EPCs are used as a candidate cell source for transplantation strategies. In recent years, a great progress was achieved in EPCs biology research, and EPCs transplantation has become a research hotspot. At present, transplanted EPCs have been used to treat ischemic diseases due to their powerful vasculogenesis and beneficial paracrine effects. Although EPCs transplantation has been proved to play an important role, the clinical application of EPCs still faces many challenges. This review briefly summarized the basic characteristics of EPCs, the process of EPCs transplantation promoting the healing of ischemic tissue, and the ways to improve the efficiency of EPCs transplantation. In addition, the application of EPCs in neurological improvement, cardiovascular and respiratory diseases and the challenges and problems in clinical application of EPCs were also discussed. In the end, the application of EPCs transplantation in regenerative medicine and tissue engineering was discussed.

Liraglutide Improves the Angiogenic Capability of EPC and Promotes Ischemic Angiogenesis in Mice under Diabetic Conditions through an Nrf2-Dependent Mechanism

The impairment in endothelial progenitor cell (EPC) functions results in dysregulation of vascular homeostasis and dysfunction of the endothelium under diabetic conditions. Improving EPC function has been considered as a promising strategy for ameliorating diabetic vascular complications. Liraglutide has been widely used as a therapeutic agent for diabetes. However, the effects and mechanisms of liraglutide on EPC dysfunction remain unclear. The capability of liraglutide in promoting blood perfusion and angiogenesis under diabetic conditions was evaluated in the hind limb ischemia model of diabetic mice. The effect of liraglutide on the angiogenic function of EPC was evaluated by cell scratch recovery assay, tube formation assay, and nitric oxide production. RNA sequencing was performed to assess the underlying mechanisms. Liraglutide enhanced blood perfusion and angiogenesis in the ischemic hindlimb of db/db mice and streptozotocin-induced type 1 diabetic mice. Additionally, liraglutide improved tube formation, cell migration, and nitric oxide production of high glucose (HG)-treated EPC. Assessment of liraglutide target pathways revealed a network of genes involved in antioxidant activity. Further mechanism study showed that liraglutide decreased the production of reactive oxygen species and increased the activity of nuclear factor erythroid 2-related factor 2 (Nrf2). Nrf2 deficiency attenuated the beneficial effects of liraglutide on improving EPC function and promoting ischemic angiogenesis under diabetic conditions. Moreover, liraglutide activates Nrf2 through an AKT/GSK3β/Fyn pathway, and inhibiting this pathway abolished liraglutide-induced Nrf2 activation and EPC function improvement. Overall, these results suggest that Liraglutide represents therapeutic potential in promoting EPC function and ameliorating ischemic angiogenesis under diabetic conditions, and these beneficial effects relied on Nrf2 activation.

The mechanisms of glycolipid metabolism disorder on vascular injury in type 2 diabetes

Patients with diabetes have severe vascular complications, such as diabetic nephropathy, diabetic retinopathy, cardiovascular disease, and neuropathy. Devastating vascular complications lead to increased mortality, blindness, kidney failure, and decreased overall quality of life in people with type 2 diabetes (T2D). Glycolipid metabolism disorder plays a vital role in the vascular complications of T2D. However, the specific mechanism of action remains to be elucidated. In T2D patients, vascular damage begins to develop before insulin resistance and clinical diagnosis. Endothelial dysregulation is a significant cause of vascular complications and the early event of vascular injury. Hyperglycemia and hyperlipidemia can trigger inflammation and oxidative stress, which impair endothelial function. Furthermore, during the pathogenesis of T2D, epigenetic modifications are aberrant and activate various biological processes, resulting in endothelial dysregulation. In the present review, we provide an overview and discussion of the roles of hyperglycemia- and hyperlipidemia-induced endothelial dysfunction, inflammatory response, oxidative stress, and epigenetic modification in the pathogenesis of T2D. Understanding the connections of glucotoxicity and lipotoxicity with vascular injury may reveal a novel potential therapeutic target for diabetic vascular complications.

Nrf2 transcriptional upregulation of IDH2 to tune mitochondrial dynamics and rescue angiogenic function of diabetic EPCs

Endothelial progenitor cells (EPCs) are reduced in number and impaired in function in diabetic patients. Whether and how Nrf2 regulates the function of diabetic EPCs remains unclear. In this study, we found that the expression of Nrf2 and its downstream genes were decreased in EPCs from both diabetic patients and db/db mice. Survival ability and angiogenic function of EPCs from diabetic patients and db/db mice also were impaired. Gain- and loss-of-function studies, respectively, showed that knockdown of Nrf2 increased apoptosis and impaired tube formation in EPCs from healthy donors and wild-type mice, while Nrf2 overexpression decreased apoptosis and rescued tube formation in EPCs from diabetic patients and db/db mice. Additionally, proangiogenic function of Nrf2-manipulated mouse EPCs was validated in db/db mice with hind limb ischemia. Mechanistic studies demonstrated that diabetes induced mitochondrial fragmentation and dysfunction of EPCs by dysregulating the abundance of proteins controlling mitochondrial dynamics; upregulating Nrf2 expression attenuated diabetes-induced mitochondrial fragmentation and dysfunction and rectified the abundance of proteins controlling mitochondrial dynamics. Further RNA-sequencing analysis demonstrated that Nrf2 specifically upregulated the transcription of isocitrate dehydrogenase 2 (IDH2), a key enzyme regulating tricarboxylic acid cycle and mitochondrial function. Overexpression of IDH2 rectified Nrf2 knockdown- or diabetes-induced mitochondrial fragmentation and EPC dysfunction. In a therapeutic approach, supplementation of an Nrf2 activator sulforaphane enhanced angiogenesis and blood perfusion recovery in db/db mice with hind limb ischemia. Collectively, these findings indicate that Nrf2 is a potential therapeutic target for improving diabetic EPC function. Thus, elevating Nrf2 expression enhances EPC resistance to diabetes-induced oxidative damage and improves therapeutic efficacy of EPCs in treating diabetic limb ischemia likely via transcriptional upregulating IDH2 expression and improving mitochondrial function of diabetic EPCs.

Recombinant DTβ4-inspired porous 3D vascular graft enhanced antithrombogenicity and recruited circulating CD93+/CD34+ cells for endothelialization

Matching material degradation with host remodeling, including endothelialization and muscular remodeling, is important to vascular regeneration. We fabricated 3D PGS-PCL vascular grafts, which presented tunable polymer components, porosity, mechanical strength, and degrading rate. Furthermore, highly porous structures enabled 3D patterning of conjugated heparin-binding peptide, dimeric thymosin β4 (DTβ4), which played key roles in antiplatelets, fibrinogenesis inhibition, and recruiting circulating progenitor cells, thereafter contributed to high patency rate, and unprecedentedly acquired carotid arterial regeneration in rabbit model. Through single-cell RNA sequencing analysis and cell tracing studies, a subset of endothelial progenitor cells, myeloid-derived CD93⁺/CD34⁺ cells, was identified as the main contributor to final endothelium regeneration. To conclude, DTβ4-inspired porous 3DVGs present adjustable physical properties, superior anticoagulating, and re-endothelializing potentials, which leads to the regeneration of small-caliber artery, thus offering a promising tool for vessel replacement in clinical applications.

The Role of Endothelial Progenitor Cells in Atherosclerosis and Impact of Anti-Lipemic Treatments on Endothelial Repair

Cardiovascular complications are associated with advanced atherosclerosis. Although atherosclerosis is still regarded as an incurable disease, at least in its more advanced stages, the discovery of endothelial progenitor cells (EPCs), with their ability to replace old and injured cells and differentiate into healthy and functional mature endothelial cells, has shifted our view of atherosclerosis as an incurable disease, and merged traditional theories of atherosclerosis pathogenesis with evolving concepts of vascular biology. EPC alterations are involved in the pathogenesis of vascular abnormalities in atherosclerosis, but many questions remain unanswered. Many currently available drugs that impact cardiovascular morbidity and mortality have shown a positive effect on EPC biology. This review examines the role of endothelial progenitor cells in atherosclerosis development, and the impact standard antilipemic drugs, including statins, fibrates, and ezetimibe, as well as more novel treatments such as proprotein convertase subtilisin/kexin type 9 (PCSK9) modulating agents and angiopoietin-like proteins (Angtpl3) inhibitors have on EPC biology.

The Role of p66Shc in Diabetes: A Comprehensive Review from Bench to Bedside

It is well-documented that diabetes is an inflammatory and oxidative disease, with an escalating global burden. Still, there is no definite treatment for diabetes or even prevention of its harmful complications. Therefore, understanding the molecular pathways associated with diabetes might help in finding a solution. p66Shc is a member of Shc family proteins, and it is considered as an oxidative stress sensor and regulator in cells. There are inconsistent data about the role of p66Shc in inducing diabetes, but accumulating evidence supports its role in the pathogenesis of diabetes-related complications, including macro and microangiopathies. There is growing hope that by understanding and targeting molecular pathways involved in this network, prevention of diabetes or its complications would be achievable. This review provides an overview about the role of p66Shc in the development of diabetes and its complications.

Single Intraosseous Simvastatin Application Induces Endothelial Progenitor Cell Mobilization and Therapeutic Angiogenesis in a Diabetic Hindlimb Ischemia Rat Model

BACKGROUND

Endothelial progenitor cells have shown the ability to enhance neovascularization. In this study, the authors tested whether intraosseous delivery of simvastatin could mobilize endothelial progenitor cells and enhance recovery in a hindlimb ischemia model.

METHODS

There are eight groups of rats in this study: normal control; type 1 diabetes mellitus control group control without drug intervention; and type 1 diabetes mellitus rats that randomly received intraosseous simvastatin (0, 0.5, or 1 mg) or oral simvastatin administration (0, 20, or 400 mg). All type 1 diabetes mellitus rats had induced hindlimb ischemia. The number of endothelial progenitor cells in peripheral blood, and serum markers, were detected. The recovery of blood flow at 21 days after treatment was used as the main outcome.

RESULTS

The authors demonstrated that endothelial progenitor cell mobilization was increased in the simvastatin 0.5- and 1-mg groups compared with the type 1 diabetes mellitus control and simvastatin 0-mg groups at 1, 2, and 3 weeks. Serum vascular endothelial growth factor levels were significantly increased at 2 weeks in the simvastatin 0.5- and 1-mg groups, in addition to the increase of the blood flow and the gastrocnemius weight at 3 weeks. Similar increase can also been seen in simvastatin 400 mg orally but not in simvastatin 20 mg orally.

CONCLUSION

These findings demonstrate that a single intraosseous administration of simvastatin mobilized endothelial progenitor cells at a dose one-hundredth of the required daily oral dose in rats, and this potent mobilization of endothelial progenitor cells markedly improved diabetic limb ischemia by means of neovascularization.

Linking Diabetes Mellitus with Alzheimer's Disease: Bioinformatics Analysis for the Potential Pathways and Characteristic Genes

As the surging epidemics with significant disability, Alzheimer's disease (AD) and type II diabetes mellitus (T2DM) with microvascular complications are widely prevalent, sharing considerable similarities in putative pathomechanism. Despite a spurt of researches on the biology, knowledge about their interactive mechanisms is still rudimentary. Applying bioinformatics ways to explore the differentially co-expressed genes contributes to achieve our objectives to find new therapeutic targets. In this study, we firstly integrated gene expression omnibus datasets (GSE28146 and GSE43950) to identify differentially expressed genes. The enrichment analysis of pivotal genes, like gene ontology and pathway signaling proceeded subsequently. Besides, the related protein-protein interaction (PPI) network was then constructed. To further explain the inner connections, we ended up unearthing the biological significance of valuable targets. As a result, a set of 712, 630, 487, and 997 genes were differentially identified in T2DM with microvascular complications and AD at incipient, moderate, and severe, respectively. The enrichment analysis involving both diseases implicated the dominance of immune system, especially the noteworthy chemokine signaling. Multiple comparisons confirmed that CACNA2D3, NUMB, and IER3 were simultaneously participate in these two conditions, whose respective associations with neurological and endocrine diseases, and regulators including interacting chemicals, transcription factors, and miRNAs were analyzed. Bioinformatics analysis eventually concluded that immune-related biological functions and pathways closely link AD and T2DM with microvascular complications. Further exploration of the regulatory factors about CACNA2D3, NUMB, and IER3 in neuroendocrine field may provide us a promising direction to discover potential strategies for the comorbidity status.

Liraglutide via Activation of AMP-Activated Protein Kinase-Hypoxia Inducible Factor-1α-Heme Oxygenase-1 Signaling Promotes Wound Healing by Preventing Endothelial Dysfunction in Diabetic Mice

Background/Aims: Diabetic foot ulcers (DFUs) present a major challenge in clinical practice, and hyperglycemia-induced angiogenesis disturbance and endothelial dysfunction likely exacerbate DFUs. The long-acting glucagon-like peptide-1 (GLP-1) analog liraglutide (Lira) is a potential activator of AMP-activated protein kinase (AMPK) that appears to enhance endothelial function and have substantial pro-angiogenesis and antioxidant stress effects. Therefore, in this study, we aimed to investigate whether the protective role of Lira in diabetic wound healing acts against the mechanisms underlying hyperglycemia-induced endothelial dysfunction and angiogenesis disturbance. Methods: Accordingly, db/db mice were assessed after receiving subcutaneous Lira injections. We also cultured human umbilical vein endothelial cells (HUVECs) in either normal or high glucose (5.5 or 33 mM glucose, respectively) medium with or without Lira for 72 h. Results: An obvious inhibition of hyperglycemia-triggered endothelial dysfunction and angiogenesis disturbance was observed; follow by a promotion of diabetic wound healing under Lira treatment combined with restored hyperglycemia-impaired AMPK signaling pathway activity. AMPKα1/2 siRNA and Compound C (Cpd C), an inhibitor of AMPK, abolished both Lira-mediated endothelial protection and pro-angiogenesis action, as well as the diabetic wound healing promoted by Lira. Furthermore, hypoxia inducible factor-1α (Hif-1α; transcription factors of AMPK substrates) knockdown in HUVECs and db/db mice demonstrated that Lira activated AMPK to prevent hyperglycemia-triggered endothelial dysfunction and angiogenesis disturbance, with a subsequent promotion of diabetic wound healing that was Hif-1α-heme oxygenase-1 (HO-1) axis-dependent. Taken together, these findings reveal that the promotion of diabetic wound healing by Lira occurs via its AMPK-dependent endothelial protection and pro-angiogenic effects, which are regulated by the Hif-1α-HO-1 axis.

HIF-1α/JMJD1A signaling regulates inflammation and oxidative stress following hyperglycemia and hypoxia-induced vascular cell injury

Background

Endothelial cell (EC) injury accelerates the progression of diabetic macrovascular complications. Hypoxia is an important cause of EC injury. Hypoxia-inducible factor-1 alpha (HIF-1α) is an important hypoxia regulatory protein. Our previous studies showed that high-glucose and hypoxic conditions could upregulate HIF-1α expression and enhance EC inflammatory injury, independently of the nuclear factor kappa-B (NF-κB) pathway. However, it is not clear whether HIF-1α plays a role in vascular disease through epigenetic-related mechanisms.

Methods

We conducted gene expression analysis and molecular mechanistic studies in human umbilical vein endothelial cells (HUVECs) induced by hyperglycemia and hypoxia using RNA sequencing (RNA-seq) and small interfering HIF-1α (si-HIF-1α). We determined HIF-1α and Jumonji domain-containing protein 1 A (JMJD1A) expression by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot, analyzed inflammatory protein secretion in the cell supernatant by enzymelinked immunosorbent assay (ELISA), and assessed protein interaction between HIF-1α and JMJD1A by chromatin immunoprecipitation (Ch-IP). We used the Cell Counting Kit8 (CCK-8) assay to analyze cell viability, and assessed oxidative stress indicators by using a detection kit and flow cytometry.

Results

High glucose and hypoxia up-regulated HIF-1α expression, and down-regulated HIF-1α decreased the level of inflammation and oxidative stress in HUVECs. To determine the downstream pathways, we observed histone demethylases genes and related pathway by RNA-sEq. Among these, JMJD1A was the most upregulated gene in histone demethylases. Moreover, we observed that HIF-1α bound to the promoter of JMJD1A, and the ameliorative effects of si-HIF-1α on oxidative stress and inflammatory cytokines in high-glucose and hypoxia-induced HUVECs were reversed by JMJD1A overexpression. Furthermore, knockdown of JMJD1A decreased inflammatory and oxidative stress injury. To determine the JMJD1A-related factors, we conducted gene expression analysis on JMJD1A-knockdown HUVECs. We observed that downregulation of inflammation and the oxidative stress pathway were enriched and FOS and FOSB might be important protective transcription factors.

Conclusions

These findings provide novel evidence that the HIF-1α/JMJD1A signaling pathway is involved in inflammation and oxidative stress in HUVECs induced by high glucose and hypoxia. Also, this pathway might act as a novel regulator of oxidative stress and inflammatory-related events in response to diabetic vascular injury and thus contribute to the pathological progression of diabetes and vascular disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-021-00283-8.

Integrins α4β1 and αVβ3 are Reduced in Endothelial Progenitor Cells from Diabetic Dyslipidemic Mice and May Represent New Targets for Therapy in Aortic Valve Disease

Diabetes reduces the number and induces dysfunction in circulating endothelial progenitor cells (EPCs) by mechanisms that are still uncovered. This study aims to evaluate the number, viability, phenotype, and function of EPCs in dyslipidemic mice with early diabetes mellitus and EPC infiltration in the aortic valve in order to identify possible therapeutic targets in diabetes-associated cardiovascular disease. A streptozotocin-induced diabetic apolipoprotein E knock-out (ApoE^-/-) mouse model was used to identify the early and progressive changes, at 4 or 7 days on atherogenic diet after the last streptozotocin or citrate buffer injection. Blood and aortic valves from diabetic or nondiabetic ApoE^-/- animals were collected.EPCs were identified as CD34 and vascular endothelial growth factor receptor 2 positive monocytes, and the expression levels of α₄β₁, α_Vβ₃, α_Vβ₅, β₁, α_Lβ₂, α₅ integrins, and C-X-C chemokine receptor type 4 chemokine receptor on EPC surface were assessed by flow cytometry. The number of CD34 positive cells in the aortic valve, previously found to be recruited progenitor cells, was measured by fluorescence microscopy. Our results show that aortic valves from mice fed 7 days with atherogenic diet presented a significantly higher number of CD34 positive cells compared with mice fed only 4 days with the same diet, and diabetes reversed this finding. We also show a reduction of circulatory EPC numbers in diabetic mice caused by cell senescence and lower mobilization. Dyslipidemia induced EPC death through apoptosis regardless of the presence of diabetes, as shown by the higher percent of propidium iodide positive cells and higher cleaved caspase-3 levels. EPCs from diabetic mice expressed α4β1 and α_Vβ₃ integrins at a lower level, while the rest of the integrins tested were unaffected by diabetes or diet. In conclusion, reduced EPC number and expression of α4β1 and αVβ3 integrins on EPCs at 4 and 7 days after diabetes induction in atherosclerosis-prone mice have resulted in lower recruitment of EPCs in the aortic valve.

Circulating Endothelial Progenitor Cells Are Preserved in Female Mice Exposed to Ambient Fine Particulate Matter Independent of Estrogen

Males have a higher risk for cardiovascular diseases (CVDs) than females. Ambient fine particulate matter (PM) exposure increases CVD risk with increased reactive oxygen species (ROS) production and oxidative stress. Endothelial progenitor cells (EPCs) are important to vascular structure and function and can contribute to the development of CVDs. The aims of the present study were to determine if sex differences exist in the effect of PM exposure on circulating EPCs in mice and, if so, whether oxidative stress plays a role. Male and female C57BL/6 mice (8–10 weeks old) were exposed to PM or a vehicle control for six weeks. ELISA analysis showed that PM exposure substantially increased the serum levels of IL-6 and IL-1β in both males and females, but the concentrations were significantly higher in males. PM exposure only increased the serum levels of TNF-α in males. Flow cytometry analysis demonstrated that ROS production was significantly increased by PM treatment in males but not in females. Similarly, the level of circulating EPCs (CD34⁺/CD133⁺ and Sca-1⁺/Flk-1⁺) was significantly decreased by PM treatment in males but not in females. Antioxidants N-acetylcysteine (NAC) effectively prevented PM exposure-induced ROS and inflammatory cytokine production and restored circulating EPC levels in male mice. In sharp contrast, circulating EPC levels remained unchanged in female mice with PM exposure, an effect that was not altered by ovariectomy. In conclusion, PM exposure selectively decreased the circulating EPC population in male mice via increased oxidative stress without a significant impact on circulating EPCs in females independent of estrogen.

Effects of structured home-based exercise training on circulating endothelial progenitor cells and endothelial function in patients with intermittent claudication

INTRODUCTION

Exercise training improves walking capacity in patients with intermittent claudication (IC). Endothelial progenitor cells (EPCs), endothelial microparticles (EMPs), and endothelial dysfunction could play a role in this process.

METHODS

We measured EPCs and EMPs in a group of 60 patients with IC, and in a control group of 20 individuals without IC, before a treadmill test and 2, 24, and 48 hours after the test. Thirty patients with IC were randomly assigned to perform a 12-week home-based exercise training program. The EPC count, flow-mediated dilation (FMD) of the brachial artery, pain-free walking time (PFWT), and maximum walking time (MWT) were measured at the baseline and after the exercise training program.

RESULTS

In patients with IC, EMPs significantly increased 2 hours after the treadmill test, whereas EPCs significantly increased after 24 hours. Among the subjects assigned to complete the training program, we observed a significant increase in the number of EPCs after 12 weeks, as well as an improvement in FMD, PFWT, and MWT. A significant correlation between the variation of EPCs, FMD, and MWT was found. The increase of EPCs and FMD were independent determinants of the walking capacity improvement, without significant interaction.

CONCLUSION

Our results suggest that EPCs mobilization contributes to the improvement of walking capacity in patients with IC undergoing structured physical training. A number of different, partly independent, mechanisms are involved in this process, and our results highlight the potential role of EMPs release and endothelial function improvement. ClinicalTrials.gov Identifier: NCT04302571.

Combination of endothelial progenitor cells and BB-94 significantly alleviates brain damage in a mouse model of diabetic ischemic stroke

Ischemic stroke is a complication of chronic macrovascular disease in type 2 diabetes. However, the pathogenesis of diabetic ischemic stroke has not yet been fully clarified. The aim of the present study was to investigate the underlying effects of endothelial progenitor cells (EPCs) and the matrix metalloproteinase inhibitor BB-94 on diabetic stroke. In vitro experiments were performed using oxygen-glucose deprivation/reoxygenation (OGD/R) model cells, established using HT22 mouse hippocampal cells. MTT assays and flow cytometry revealed that BB-94 prominently induced the proliferation of the OGD/R model cells and prevented their apoptosis. When EPCs and BB-94 were applied to the OGD/R model cells in combination, proliferation was further accelerated and oxidative damage was attenuated. In vivo experiments were also performed using a middle cerebral artery occlusion (MCAO) mouse model. The results of modified neurological severity scoring and oxidative stress marker analysis demonstrated that EPCs and BB-94 prominently alleviated cerebral ischemia/reperfusion injury in the MCAO model mice. Furthermore, reverse transcription-quantitative PCR and western blot assays revealed that EPCs in combination with BB-94 significantly downregulated the expression of matrix metalloproteinases (MMPs) and upregulated the expression of tissue inhibitor of metalloproteinases 1 in OGD/R cells and MCAO model mice. The results suggest that EPCs were successfully isolated and identified, and the OGD/R cell and MCAO mouse models were successfully established. They also indicate that EPCs alone or in combination with BB-94 may exert protective effects against ischemic stroke via the reduction of MMP expression.

Nicotinamide Riboside Enhances Endothelial Precursor Cell Function to Promote Refractory Wound Healing Through Mediating the Sirt1/AMPK Pathway

Lack of vascularization is directly associated with refractory wound healing in diabetes mellitus (DM). Enrichment of endothelial precursor cells (EPCs) is a promising but challenging approach for the treatment of diabetic wounds. Herein, we investigate the action of nicotinamide riboside (NR) on EPC function for improved healing of diabetic wounds. Db/db mice that were treated with NR-supplemented food (400 mg/kg/d) for 12 weeks exhibited higher wound healing rates and angiogenesis than untreated db/db mice. In agreement with this phenotype, NR supplementation significantly increased the number of blood EPCs and bone marrow (BM)-derived EPCs of db/db mice, as well as the tube formation and adhesion functions of BM-EPCs. Furthermore, NR-supplemented BM-EPCs showed higher expression of sirtuin 1 (Sirt1), phosphorylated adenosine monophosphate–activated protein kinase (p-AMPK), and lower expression of acetylated peroxisome proliferator–activated receptor γ coactivator (PGC-1α) than BM-EPCs isolated from untreated db/db mice. Knockdown of Sirt1 in BM-EPCs significantly abolished the tube formation and adhesion function of NR as well as the expression of p-AMPK and deacetylated PGC-1a. Inhibition of AMPK abolished the NR-regulated EPC function but had no effect on Sirt1 expression, demonstrating that NR enhances EPC function through the Sirt1-AMPK pathway. Overall, this study demonstrates that the oral uptake of NR enhances the EPC function to promote diabetic wound healing, indicating that NR supplementation might be a promising strategy to prevent the progression of diabetic complications.

Scutellarin ameliorates high glucose-induced vascular endothelial cells injury by activating PINK1/Parkin-mediated mitophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Scutellarin (Scu) is one of the main active ingredients of Erigeron breviscapus (Vant.) Hand.-Mazz which has been used to treat cardiovascular disease including vascular dysfunction caused by diabetes. Scu also has a protective effect on vascular endothelial cells against hyperglycemia. However, molecular mechanisms underlying this effect are not clear.

AIM OF THE STUDY

This aim of this study was to investigate the effect of Scu on human umbilical vein endothelial cells (HUVECs) injury induced by high glucose (HG), especially the regulation of PTEN-induced kinase 1 (PINK1)/Parkin-mediated mitophagy.

MATERIALS AND METHODS

HUVECs were exposed to HG to induce vascular endothelial cells injury in vitro. Cell viability was assessed by MTT assay. The extent of cell apoptosis was measured by Hoechst staining and flow cytometry. Mitophagy was assayed by fluorescent immunostaining, transmission electron microscope and immunoblot. Besides, virtual docking was conducted to validate the interaction of PINK1 protein and Scu.

RESULTS

We found that Scu significantly increased cell viability in HG-treated HUVECs. Scu reduces the expression of Bcl-2, Bax and cytochrome C (Cyt.c) to inhibit apoptosis through a mitochondria-dependent pathway. Meanwhile, Scu improved the overload of reactive oxygen species (ROS), superoxide dismutase (SOD) activity and SOD2 protein expression, and reversed the collapse of mitochondrial membrane potential. Besides, Scu increased autophagic flux, improved the expression of microtubule-associated protein 1 light chain 3 Ⅱ (LC3 II), Beclin 1 and autophagy-related gene 5 (Atg 5) and decreased the expression of Sequestosome1/P62 in HG-treated HUVECs. Furthermore, Scu improved the expressions of PINK1, Parkin, and Mitofusin2, which revealed the enhancement of mitophagy. Moreover, the beneficial effects of Scu on HG-induced low expression of Parkin, overproduction of ROS, and over expressions of P62, Cyt.c and Cleaved caspase-3 were weakened by PINK1 gene knockdown. Molecular docking suggested good interaction of Scu and PINK1 protein.

CONCLUSION

These results suggest that Scu may protect vascular endothelial cells against hyperglycemia-induced injury by up-regulating mitophagy via PINK1/Parkin signal pathway.

Upregulating CXCR7 accelerates endothelial progenitor cell-mediated endothelial repair by activating Akt/Keap-1/Nrf2 signaling in diabetes mellitus

Background

Endothelial progenitor cell (EPC) dysfunction contributes to vascular disease in diabetes mellitus. However, the molecular mechanism underlying EPC dysfunction and its contribution to delayed reendothelialization in diabetes mellitus remain unclear. Our study aimed to illustrate the potential molecular mechanism underlying diabetic EPC dysfunction in vivo and in vitro. Furthermore, we assessed the effect of EPC transplantation on endothelial regeneration in diabetic rats.

Methods

Late outgrowth EPCs were isolated from the bone marrow of rats for in vivo and in vitro studies. In vitro functional assays and Western blotting were conducted to reveal the association between C-X-C chemokine receptor type 7 (CXCR7) expression and diabetic EPC dysfunction. To confirm the association between cellular CXCR7 levels and EPC function, CXCR7 expression in EPCs was upregulated and downregulated via lentiviral transduction and RNA interference, respectively. Western blotting was used to reveal the potential molecular mechanism by which the Stromal-Derived Factor-1 (SDF-1)/CXCR7 axis regulates EPC function. To elucidate the role of the SDF-1/CXCR7 axis in EPC-mediated endothelial regeneration, a carotid artery injury model was established in diabetic rats. After the model was established, saline-treated, diabetic, normal, or CXCR7-primed EPCs were injected via the tail vein.

Results

Diabetic EPC dysfunction was associated with decreased CXCR7 expression. Furthermore, EPC dysfunction was mimicked by knockdown of CXCR7 in normal EPCs. However, upregulating CXCR7 expression reversed the dysfunction of diabetic EPCs. The SDF-1/CXCR7 axis positively regulated EPC function by activating the AKT-associated Kelch-like ECH-associated protein 1 (keap-1)/nuclear factor erythroid 2-related factor 2 (Nrf2) axis, which was reversed by blockade of AKT and Nrf2. Transplantation of CXCR7-EPCs accelerated endothelial repair and attenuated neointimal hyperplasia in diabetes mellitus more significantly than transplantation of diabetic or normal EPCs. However, the therapeutic effect of CXCR7-EPC transplantation on endothelial regeneration was reversed by knockdown of Nrf2 expression.

Conclusions

Dysfunction of diabetic EPCs is associated with decreased CXCR7 expression. Furthermore, the SDF-1/CXCR7 axis positively regulates EPC function by activating the AKT/keap-1/Nrf2 axis. CXCR7-primed EPCs might be useful for endothelial regeneration in diabetes-associated vascular disease.

Chemically Modified SDF-1α mRNA Promotes Random Flap Survival by Activating the SDF-1α/CXCR4 Axis in Rats

Random skin flaps are frequently applied in plastic and reconstructive surgery for patients suffering from soft tissue defects caused by congenital deformities, trauma and tumor resection. However, ischemia and necrosis in distal parts of random skin flaps remains a common challenge that limits the clinical application of this procedure. Recently, chemically modified mRNA (modRNA) was found to have great therapeutic potential. Here, we explored the potential of fibroblasts engineered to express modified mRNAs encoding the stromal cell-derived factor-1α (SDF-1α) to improve vascularization and survival of therapeutic random skin flaps. Our study showed that fibroblasts pre-treated with SDF-1α modRNA have the potential to salvage ischemic skin flaps. Through a detailed analysis, we revealed that a fibroblast SDF-1α modRNA combinatorial treatment dramatically reduced tissue necrosis and significantly promoted neovascularization in random skin flaps compared to that in the control and vehicle groups. Moreover, SDF-1α modRNA transcription in fibroblasts promoted activation of the SDF-1α/CXCR4 pathway, with concomitant inactivation of the MEK/ERK, PI3K/AKT, and JAK2/STAT3 signaling pathways, indicating a possible correlation with cell proliferation and migration. Therefore, fibroblast-mediated SDF-1α modRNA expression represents a promising strategy for random skin flap regeneration.

The Effect of Sex Differences on Endothelial Function and Circulating Endothelial Progenitor Cells in Hypertriglyceridemia

Background

Men have a higher risk and earlier onset of cardiovascular diseases compared with premenopausal women. Hypertriglyceridemia is an independent risk factor for the occurrence of ischemic heart disease. Endothelial dysfunction is related to the development of ischemic heart disease. Whether sex differences will affect the circulating endothelial progenitor cells (EPCs) and endothelial function in hypertriglyceridemia patients or not is not clear.

Methods

Forty premenopausal women and forty age- and body mass index (BMI)-matched men without cardiovascular and metabolic disease were recruited and then divided into four groups: normotriglyceridemic women (women with serum triglycerides level <150 mg/dl), hypertriglyceridemic women (women with serum triglycerides level ≥150 mg/dl), normotriglyceridemic men (men with serum triglycerides level <150 mg/dl), and hypertriglyceridemic men (men with serum triglycerides level ≥150 mg/dl). Peripheral blood was obtained and evaluated. Flow-mediated dilatation (FMD), the number and activity of circulating EPCs, and the levels of nitric oxide (NO), vascular endothelial growth factor (VEGF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) in plasma and culture medium were measured.

Results

The number and activity of circulating EPCs, as well as the level of NO in plasma or culture medium, were remarkably increased in premenopausal females compared with those in males both in the hypertriglyceridemic group and the normotriglyceridemic group. The EPC counts and activity, as well as the production of NO, were restored in hypertriglyceridemic premenopausal women compared with those in normal women. However, in hypertriglyceridemic men, the EPC counts and activity, as well as levels of NO, were significantly reduced. The values of VEGF and GM-CSF were without statistical change.

Conclusions

The present study firstly demonstrated that there were sex differences in the number and activity of circulating EPCs in hyperglyceridemia patients. Hypertriglyceridemic premenopausal women displayed restored endothelial functions, with elevated NO production, probably mediated by estradiol. We provided a new insight to explore the clinical biomarkers and therapeutic strategies for hypertriglyceridemia-related vascular damage.

Endothelial progenitor cells as the target for cardiovascular disease prediction, personalized prevention, and treatments: progressing beyond the state-of-the-art

Stimulated by the leading mortalities of cardiovascular diseases (CVDs), various types of cardiovascular biomaterials have been widely investigated in the past few decades. Although great therapeutic effects can be achieved by bare metal stents (BMS) and drug-eluting stents (DES) within months or years, the long-term complications such as late thrombosis and restenosis have limited their further applications. It is well accepted that rapid endothelialization is a promising approach to eliminate these complications. Convincing evidence has shown that endothelial progenitor cells (EPCs) could be mobilized into the damaged vascular sites systemically and achieve endothelial repair in situ, which significantly contributes to the re-endothelialization process. Therefore, how to effectively capture EPCs via specific molecules immobilized on biomaterials is an important point to achieve rapid endothelialization. Further, in the context of predictive, preventive, personalized medicine (PPPM), the abnormal number alteration of EPCs in circulating blood and certain inflammation responses can also serve as important indicators for predicting and preventing early cardiovascular disease. In this contribution, we mainly focused on the following sections: the definition and classification of EPCs, the mechanisms of EPCs in treating CVDs, the potential diagnostic role of EPCs in predicting CVDs, as well as the main strategies for cardiovascular biomaterials to capture EPCs.

Combined Transplantation of Adipose Tissue-Derived Stem Cells and Endothelial Progenitor Cells Improve Diabetic Erectile Dysfunction in a Rat Model

Erectile dysfunction (ED) is a common complication in men suffered with diabetic mellitus. Stem cell transplantation is a promising strategy for the treatment of diabetic ED (DED). In this study, we evaluated whether combined transplantation of adipose tissue-derived stem cells (ADSCs) and endothelial progenitor cells (EPCs) could improve the erectile function of the DED rat model. DED rats were induced via intraperitoneal injection of streptozotocin (50 mg/kg), and ED was screened by apomorphine (100 mg/kg). DED rats were divided into 4 groups (n = 14 each): DED, ADSC, EPC, and ADSC/EPC group. Another 14 age-matched male SD rats with normal erectile function were served as the normal group. The normal group and the DED group were received intracavernous injection with phosphate-buffered saline (PBS). And the other groups were received intracavernous injection with ADSCs (1 × 10⁶), EPCs (1 × 10⁶), and ADSCs/EPCs (0.5 × 10⁶/0.5 × 10⁶), respectively. The total intracavernous pressure (ICP) and mean arterial pressure (MAP) were recorded at day 28 after injection. The endothelium, smooth muscle, and penile dorsal nerves were assessed within cavernoursal tissue. On day 28 after injection, the ADSC/EPC group displayed more significantly enhanced ICP and ICP/MAP than the DED or ADSC or EPC group (p < 0.05). Immunofluorescent analysis and western blot demonstrated that the improvement of erectile function in the ADSC/EPC5 group was associated with increased expression of endothelial marker (CD31) and the correction of eNOS-cGMP-NO signaling. More 5-ethynyl-2′-deoxyuridine- (EdU-) positive EPCs could be found lining in the cavernous endothelial layer in the ADSC/EPC group than the EPC group, which was attributed to the paracrine of vascular endothelial growth factor (VEGF) and stromal-derived factor-1 (SDF-1) by ADSCs. Combined transplantation of ADSCs and EPCs has a synergic effect in repairing the endothelial function of DED rats, and the underlying mechanism might be the paracrine of VEGF and SDF-1 by ADSCs, which improves the recruitment and proliferation of EPCs in the cavernosum.

Endothelial progenitor cell transplantation restores vascular injury in mice after whole-brain irradiation

Vascular damage plays an important role in the pathogenesis of radiation-induced brain injury (RBI). Endothelial progenitor cells (EPCs) are responsible for maintaining and repairing endothelial function, and have become a promising method for the treatment of cerebrovascular diseases. However, whether EPC transplantation plays a protective role in RBI has not been fully elucidated. Therefore, the present study investigated the effects of bone marrow-derived EPC transplantation in a whole-brain irradiation (WBI) mouse model. Mice were divided into the three groups: control group, irradiation group and EPCs group. Phosphate buffered saline or EPCs were intravenously injected into mice one week after irradiation, and brains were analyzed eight weeks after injection. Flow cytometry demonstrated that irradiation led to a significant reduction in the peripheral blood EPC count; however, EPC transplantation led to a significant increase in the circulating EPCs. Intravital two-photon imaging and western blotting demonstrated that EPC transplantation reversed the effects of irradiation by decreasing blood-brain barrier permeability and increasing the expression of tight junction proteins in the brain. Additionally, immunofluorescence staining revealed that the brain microvascular density was higher in the EPCs group than the irradiation group. Therefore, EPC transplantation may restore damage caused by WBI to the blood-brain barrier, tight junctions, and cerebral capillary density. These results highlight the potential beneficial effects of EPC transplantation on vascular damage induced by RBI.

Human umbilical cord blood-mesenchymal stem cell-derived secretome in combination with atorvastatin enhances endothelial progenitor cells proliferation and migration

Background: Human umbilical cord blood-mesenchymal stem cell (hUCB-MSC)-derived secretome is known to be able to promote neovascularization and angiogenesis, so it is also thought to have a capability to modulate endothelial progenitor cell (EPC) functions. Atorvastatin is the cornerstone of coronary artery disease (CAD) treatment which can enhance EPCs proliferation and migration. This study aims to analyze the effect of the hUCB-MSC-derived secretome and its combination with atorvastatin toward EPCs proliferation and migration. Methods: EPCs were isolated from a CAD patient's peripheral blood. Cultured EPCs were divided into a control group and treatment group of 2.5 µM atorvastatin, hUCB-MSC-derived secretome (2%, 10%, and 20% concentration) and its combination. EPCs proliferation was evaluated using an MTT cell proliferation assay, and EPC migration was evaluated using a Transwell migration assay kit. Results: This research showed that hUCB-MSC-derived secretomes significantly increase EPC proliferation and migration in a dose-dependent manner. The high concentration of hUCB-MSC-derived secretome were shown to be superior to atorvastatin in inducing EPC proliferation and migration (p<0.001). A combination of the hUCB-MSC-derived secretome and atorvastatin shown to improve EPCs proliferation and migration compared to hUCB-MSC-derived secretome treatment or atorvastatin alone (p<0.001). Conclusions: This study concluded that the hUCB-MSC-derived secretome work synergistically with atorvastatin treatment in improving EPCs proliferation and migration.

Human umbilical cord blood-mesenchymal stem cell-derived secretome in combination with atorvastatin enhances endothelial progenitor cells proliferation and migration

Background: Human umbilical cord blood-mesenchymal stem cell (hUCB-MSC)-derived secretome is known to be able to promote neovascularization and angiogenesis, so it is also thought to have a capability to modulate endothelial progenitor cell (EPC) functions. Atorvastatin is the cornerstone of coronary artery disease (CAD) treatment which can enhance EPCs proliferation and migration. This study aims to analyze the effect of the hUCB-MSC-derived secretome and its combination with atorvastatin toward EPCs proliferation and migration. Methods: EPCs were isolated from a CAD patient's peripheral blood. Cultured EPCs were divided into a control group and treatment group of 2.5 µM atorvastatin, hUCB-MSC-derived secretome (2%, 10%, and 20% concentration) and its combination. EPCs proliferation was evaluated using an MTT cell proliferation assay, and EPC migration was evaluated using a Transwell migration assay kit. Results: This research showed that hUCB-MSC-derived secretomes significantly increase EPC proliferation and migration in a dose-dependent manner. The high concentration of hUCB-MSC-derived secretome were shown to be superior to atorvastatin in inducing EPC proliferation and migration (p<0.001). A combination of the hUCB-MSC-derived secretome and atorvastatin shown to improve EPCs proliferation and migration compared to hUCB-MSC-derived secretome treatment or atorvastatin alone (p<0.001). Conclusions: This study concluded that the hUCB-MSC-derived secretome work synergistically with atorvastatin treatment in improving EPCs proliferation and migration.

When Good Guys Turn Bad: Bone Marrow's and Hematopoietic Stem Cells' Role in the Pathobiology of Diabetic Complications

Diabetes strongly contributes to the development of cardiovascular disease, the leading cause of mortality and morbidity in these patients. It is widely accepted that hyperglycemia impairs hematopoietic stem/progenitor cell (HSPC) mobilization from the bone marrow (BM) by inducing stem cell niche dysfunction. Moreover, a recent study demonstrated that type 2 diabetic patients are characterized by significant depletion of circulating provascular progenitor cells and increased frequency of inflammatory cells. This unbalance, potentially responsible for the reduction of intrinsic vascular homeostatic capacity and for the establishment of a low-grade inflammatory status, suggests that bone BM-derived HSPCs are not only victims but also active perpetrators in diabetic complications. In this review, we will discuss the most recent literature on the molecular mechanisms underpinning hyperglycemia-mediated BM dysfunction and differentiation abnormality of HSPCs. Moreover, a section will be dedicated to the new glucose-lowering therapies that by specifically targeting the culprits may prevent or treat diabetic complications.

Identification of differentially expressed genes in the endothelial precursor cells of patients with type 2 diabetes mellitus by bioinformatics analysis

Type 2 diabetes mellitus (DM) is a metabolic disease with worldwide prevalence that is associated with a decrease in the number and function of endothelial progenitor cells (EPCs). The aim of the present study was to explore the potential hub genes of EPCs in patients with type 2 DM. Differentially expressed genes (DEGs) were screened from a public microarray dataset (accession no. GSE43950). Pathway and functional enrichment analyses were performed using the Database for Annotation, Visualization and Integrated Discovery. The protein-protein interaction (PPI) network was visualized. The most significantly clustered modules and hub genes were identified using Cytoscape. Furthermore, hub genes were validated by quantitative PCR analysis of EPCs isolated from diabetic and normal subjects. Subsequently, weighted gene co-expression network analysis (WGCNA) was performed to identify the modules incorporating the genes exhibiting the most significant variance. A total of 970 DEGs were obtained and they were mainly accumulated in inflammation-associated pathways. A total of 9 hub genes were extracted from the PPI network and the highest differential expression was determined for the interleukin 8 (IL8) and CXC chemokine ligand 1 (CXCL1) genes. In the WGCNA performed to determine the modules associated with type 2 DM, one module incorporated IL8 and CXCL1. Finally, pathway enrichment of 10% genes in the pink module ordered by intramodular connectivity (IC) was associated with the IL17 and the chemokine signaling pathways. The present results revealed that the expression of IL8 and CXCL1 may serve important roles in the pathophysiology of EPCs during type 2 DM and inflammatory response may be critical for the reduced number and hypofunction of EPCs isolated from patients with diabetes.

Rosiglitazone accelerates wound healing by improving endothelial precursor cell function and angiogenesis in db/db mice

Background & Aims

Endothelial precursor cell (EPC) dysfunction is one of the risk factors for diabetes mellitus (DM) which results in delayed wound healing. Rosiglitazone (RSG) is a frequently prescribed oral glucose-lowering drug. Previous studies have shown the positive effects of RSG on ameliorating EPC dysfunction in diabetic patients. Interestingly, knowledge about RSG with regard to the wound healing process caused by DM is scarce. Therefore, in this study, we investigated the possible actions of RSG on wound healing and the related mechanisms involved in db/db diabetic mice.

Methods

Db/db mice with spontaneous glucose metabolic disorder were used as a type 2 DM model. RSG (20 mg/kg/d, i.g.,) was administered for 4 weeks before wound creation and bone marrow derived EPC (BM-EPC) isolation. Wound closure was assessed by wound area and CD31 staining. Tubule formation and migration assays were used to judge the function of the BM-EPCs. The level of vascular endothelial growth factor (VEGF), stromal cell derived factor-1α (SDF-1α) and insulin signaling was determined by ELISA. Cell viability of the BM-EPCs was measured by CCK-8 assay.

Results

RSG significantly accelerated wound healing and improved angiogenesis in db/db mice. Bioactivities of tube formation and migration were decreased in db/db mice but were elevated by RSG. Level of both VEGF and SDF-1α was increased by RSG in the BM-EPCs of db/db mice. Insulin signaling was elevated by RSG reflected in the phosphorylated-to-total AKT in the BM-EPCs. In vitro, RSG improved impaired cell viability and tube formation of BM-EPCs induced by high glucose, but this was prevented by the VEGF inhibitor avastin.

Conclusion

Our data demonstrates that RSG has benefits for wound healing and angiogenesis in diabetic mice, and was partially associated with improvement of EPC function through activation of VEGF and stimulation of SDF-1α in db/db mice.

Endothelial Toxicity of High Glucose and its by-Products in Diabetic Kidney Disease

Alterations of renal endothelial cells play a crucial role in the initiation and progression of diabetic kidney disease. High glucose per se, as well as glucose by-products, induce endothelial dysfunction in both large vessels and the microvasculature. Toxic glucose by-products include advanced glycation end products (AGEs), a group of modified proteins and/or lipids that become glycated after exposure to sugars, and glucose metabolites produced via the polyol pathway. These glucose-related endothelio-toxins notably induce an alteration of the glomerular filtration barrier by increasing the permeability of glomerular endothelial cells, altering endothelial glycocalyx, and finally, inducing endothelial cell apoptosis. The glomerular endothelial dysfunction results in albuminuria. In addition, high glucose and by-products impair the endothelial repair capacities by reducing the number and function of endothelial progenitor cells. In this review, we summarize the mechanisms of renal endothelial toxicity of high glucose/glucose by-products, which encompass changes in synthesis of growth factors like TGF-β and VEGF, induction of oxidative stress and inflammation, and reduction of NO bioavailability. We finally present potential therapies to reduce endothelial dysfunction in diabetic kidney disease.

YBX-1 mediated sorting of miR-133 into hypoxia/reoxygenation-induced EPC-derived exosomes to increase fibroblast angiogenesis and MEndoT

Background

Myocardial fibrosis is a common pathophysiological change in cardiovascular disease, which can cause cardiac dysfunction and even sudden death. Excessively activated fibroblasts proliferate and secret excessive extracellular matrix (ECM) components, resulting in normal cardiac structural damage and cardiac fibrosis. We previously found that human endothelial progenitor cell (EPC)-derived exosomes, after hypoxia/reoxygenation (H/R) induction, could significantly increase the mesenchymal-endothelial transition (MEndoT) compared to normal culture EPC-derived exosomes. Exosomes have been shown to carry different nucleic acids, including microRNAs. However, the effects of microRNAs in EPC-derived exosomes on MEndoT and myocardial fibrosis remain unknown.

Methods

EPCs were isolated from human peripheral blood, and fibroblasts were isolated from rat hearts, then transfected with miR-133 inhibitor, si-YBX-1, and ov-YBX-1 into EPCs. After H/R induction for 48 h, isolation and characterization of exosomes derived from human EPCs were performed. Finally, fibroblasts were treated by exosome at 48 h. The expression of miR-133 was measured by qRT-PCR; YBX-1 expression was measured by qRT-PCR and western blot. Angiopoiesis was measured by tube formation assay. Endothelial markers and fibrosis markers were measured by western blot.

Results

H/R treatment promoted miR-133 expression in EPCs and EPC-derived exosomes. miR-133 could be incorporated into exosomes and transmitted to cardiac fibroblasts, increasing the angiogenesis and MEndoT of cardiac fibroblasts. miR-133 silencing in H/R-induced EPCs could inhibit miR-133 expression in EPCs and EPCs-derived exosomes. miR-133 silencing in H/R-induced EPCs could inhibit the angiogenesis and MEndoT of cardiac fibroblasts and reverse the effect of H/R treatment. Additionally, miR-133 was specially sorted into H/R-induced EPC-derived exosomes via YBX-1. YBX-1 silencing inhibited miR-133 transfer and reduced fibroblast angiogenesis and MEndoT.

Conclusion

miR-133 was specially sorted into H/R-induced EPC-derived exosomes via YBX-1 to increase fibroblast angiogenesis and MEndoT.