Reprogramming tumor-associated macrophages to outcompete endovascular endothelial progenitor cells and suppress tumor neoangiogenesis.

Tumors develop by invoking a supportive environment characterized by aberrant angiogenesis and infiltration of tumor-associated macrophages (TAMs). In a transgenic model of breast cancer, we found that TAMs localized to the tumor parenchyma and were smaller than mammary tissue macrophages. TAMs had low activity of the metabolic regulator mammalian/mechanistic target of rapamycin complex 1 (mTORC1), and depletion of negative regulator of mTORC1 signaling, tuberous sclerosis complex 1 (TSC1), in TAMs inhibited tumor growth in a manner independent of adaptive lymphocytes. Whereas wild-type TAMs exhibited inflammatory and angiogenic gene expression profiles, TSC1-deficient TAMs had a pro-resolving phenotype. TSC1-deficient TAMs relocated to a perivascular niche, depleted protein C receptor (PROCR)-expressing endovascular endothelial progenitor cells, and rectified the hyperpermeable blood vasculature, causing tumor tissue hypoxia and cancer cell death. TSC1-deficient TAMs were metabolically active and effectively eliminated PROCR-expressing endothelial cells in cell competition experiments. Thus, TAMs exhibit a TSC1-dependent mTORC1-low state, and increasing mTORC1 signaling promotes a pro-resolving state that suppresses tumor growth, defining an innate immune tumor suppression pathway that may be exploited for cancer immunotherapy.

Novel Angiogenesis Role of GLP-1(32-36) to Rescue Diabetic Ischemic Lower Limbs via GLP-1R-Dependent Glycolysis in Mice.

BACKGROUND: Restoring the capacity of endothelial progenitor cells (EPCs) to promote angiogenesis is the major therapeutic strategy of diabetic peripheral artery disease. The aim of this study was to investigate the effects of GLP-1 (glucagon-like peptide 1; 32-36)-an end product of GLP-1-on angiogenesis of EPCs and T1DM (type 1 diabetes) mice, as well as its interaction with the classical GLP-1R (GLP-1 receptor) pathway and its effect on mitochondrial metabolism. METHODS: In in vivo experiments, we conducted streptozocin-induced type 1 diabetic mice as a murine model of unilateral hind limb ischemia to examine the therapeutic potential of GLP-1(32-36) on angiogenesis. We also generated Glp1r-/- mice to detect whether GLP-1R is required for angiogenic function of GLP-1(32-36). In in vitro experiments, EPCs isolated from the mouse bone marrow and human umbilical cord blood samples were used to detect GLP-1(32-36)-mediated angiogenic capability under high glucose treatment. RESULTS: We demonstrated that GLP-1(32-36) did not affect insulin secretion but could significantly rescue angiogenic function and blood perfusion in ischemic limb of streptozocin-induced T1DM mice, a function similar to its parental GLP-1. We also found that GLP-1(32-36) promotes angiogenesis in EPCs exposed to high glucose. Specifically, GLP-1(32-36) has a causal role in improving fragile mitochondrial function and metabolism via the GLP-1R-mediated pathway. We further demonstrated that GLP-1(32-36) rescued diabetic ischemic lower limbs by activating the GLP-1R-dependent eNOS (endothelial NO synthase)/cGMP/PKG (protein kinase G) pathway. CONCLUSIONS: Our study provides a novel mechanism with which GLP-1(32-36) acts in modulating metabolic reprogramming toward glycolytic flux in partnership with GLP-1R for improved angiogenesis in high glucose-exposed EPCs and T1DM murine models. We propose that GLP-1(32-36) could be used as a monotherapy or add-on therapy with existing treatments for peripheral artery disease. REGISTRATION: URL: www.ebi.ac.uk/metabolights/; Unique identifier: MTBLS9543.

Senescence induces miR-409 to down-regulate CCL5 and impairs angiogenesis in endothelial progenitor cells.

This study explores the impact of senescence on autocrine C-C motif chemokine ligand 5 (CCL5) in human endothelial progenitor cell (EPCs), addressing the poorly understood decline in number and function of EPCs during ageing. We examined the effects of replication-induced senescence on CCL5/CCL5 receptor (CCR5) signalling and angiogenic activity of EPCs in vitro and in vivo. We also explored microRNAs controlling CCL5 secretion in senescent EPCs, its impact on EPC angiogenic activity, and validated our findings in humans. CCL5 secretion and CCR5 levels in senescent EPCs were reduced, leading to attenuated angiogenic activity. CCL5 enhanced EPC proliferation via the CCR5/AKT/P70S6K axis and increased vascular endothelial growth factor (VEGF) secretion. Up-regulation of miR-409 in senescent EPCs resulted in decreased CCL5 secretion, inhibiting the angiogenic activity, though these negative effects were counteracted by the addition of CCL5 and VEGF. In a mouse hind limb ischemia model, CCL5 improved the angiogenic activity of senescent EPCs. Analysis involving 62 healthy donors revealed a negative association between CCL5 levels, age and Framingham Risk Score. These findings propose CCL5 as a potential biomarker for detection of EPC senescence and cardiovascular risk assessment, suggesting its therapeutic potential for age-related cardiovascular disorders.

HOXD9 regulated mitophagy to promote endothelial progenitor cells angiogenesis and deep vein thrombosis recanalization and resolution.

BACKGROUND: Deep vein thrombosis (DVT) is a common vascular surgical disease caused by the coagulation of blood in the deep veins, and predominantly occur in the lower limbs. Endothelial progenitor cells (EPCs) are multi-functional stem cells, which are precursors of vascular endothelial cells. EPCs have gradually evolved into a promising treatment strategy for promoting deep vein thrombus dissolution and recanalization through the stimulation of various physical and chemical factors. METHODS: In this study, we utilized a mouse DVT model and performed several experiments including qRT-PCR, Western blot, tube formation, wound healing, Transwell assay, immunofluorescence, flow cytometry analysis, and immunoprecipitation to investigate the role of HOXD9 in the function of EPCs cells. The therapeutic effect of EPCs overexpressing HOXD9 on the DVT model and its mechanism were also explored. RESULTS: Overexpression of HOXD9 significantly enhanced the angiogenesis and migration abilities of EPCs, while inhibiting cell apoptosis. Additionally, results indicated that HOXD9 specifically targeted the HRD1 promoter region and regulated the downstream PINK1-mediated mitophagy. Interestingly, intravenous injection of EPCs overexpressing HOXD9 into mice promoted thrombus dissolution and recanalization, significantly decreasing venous thrombosis. CONCLUSIONS: The findings of this study reveal that HOXD9 plays a pivotal role in stimulating vascular formation in endothelial progenitor cells, indicating its potential as a therapeutic target for DVT management.

Dulaglutide restores endothelial progenitor cell levels in diabetic mice and mitigates high glucose-induced endothelial injury through SIRT1-mediated mitochondrial fission.

Type 2 diabetes mellitus (T2DM) significantly impairs the functionality and number of endothelial progenitor cells (EPCs) and resident endothelial cells, critical for vascular repair and regeneration, exacerbating the risk of vascular complications. GLP-1 receptor agonists, like dulaglutide, have emerged as promising therapeutic agents due to their multifaceted effects, including the enhancement of EPC activity and protection of endothelial cells. This study investigates dulaglutide's effects on peripheral blood levels of CD34+ and CD133+ cells in a mouse model of lower limb ischemia and its protective mechanisms against high-glucose-induced damage in endothelial cells. Results demonstrated that dulaglutide significantly improves blood flow, reduces tissue damage and inflammation in ischemic limbs, and enhances glycemic control. Furthermore, dulaglutide alleviated high-glucose-induced endothelial cell damage, evident from improved tube formation, reduced reactive oxygen species accumulation, and restored endothelial junction integrity. Mechanistically, dulaglutide mitigated mitochondrial fission in endothelial cells under high-glucose conditions, partly through maintaining SIRT1 expression, which is crucial for mitochondrial dynamics. This study reveals the potential of dulaglutide as a therapeutic option for vascular complications in T2DM patients, highlighting its role in improving endothelial function and mitochondrial integrity.

Astragaloside IV promotes exosome secretion of endothelial progenitor cells to regulate PI3KR2/SPRED1 signaling and inhibit pyroptosis of diabetic endothelial cells.

BACKGROUND AIMS: Treating chronic non-healing diabetic wounds and achieving complete skin regeneration has always been a critical clinical challenge. METHODS: In order to address this issue, researchers conducted a study aiming to investigate the role of miR-126-3p in regulating the downstream gene PIK3R2 and promoting diabetic wound repair in endothelial progenitor cell (EPC)-derived extracellular vesicles. The study involved culturing EPCs with astragaloside IV, transfecting them with miR-126-3p inhibitor or mock plasmid, interfering with high glucose-induced damage in human umbilical vein endothelial cells (HUVECs) and treating diabetic skin wounds in rats. RESULTS: The healing of rat skin wounds was observed through histological staining. The results revealed that treatment with miR-126-3p-overexpressing EPC-derived extracellular vesicles accelerated the healing of rat skin wounds and resulted in better tissue repair with slower scar formation. In addition, the transfer of EPC-derived extracellular vesicles with high expression of miR-126-3p to high glucose-damaged HUVECs increased their proliferation and invasion, reduced necrotic and apoptotic cell numbers and improved tube formation. In this process, the expression of angiogenic factors vascular endothelial growth factor (VEGF)A, VEGFB, VEGFC, basic fibroblast growth factor and Ang-1 significantly increased, whereas the expression of caspase-1, NRLP3, interleukin-1ß, inteleukin-18, PIK3R2 and SPRED1 was suppressed. Furthermore, miR-126-3p was able to target and inhibit the expression of the PIK3R2 gene, thereby restoring the proliferation and migration ability of high glucose-damaged HUVEC. CONCLUSIONS: In summary, these research findings demonstrate the important role of miR-126-3p in regulating downstream genes and promoting diabetic wound repair, providing a new approach for treating chronic non-healing diabetic wounds.

LncRNA PVT1 promotes strong stemness and endothelial progenitor cell characteristics in renal carcinoma stem cells.

Renal cancer stem cells (RCSCs) derived from clear cell renal cell carcinoma (ccRCC) tissues with higher microvessel density (MVD) have strong stemness and endothelial progenitor cells-like (EPCs-like) characteristics. A high level of lncRNA PVT1 expression is essential for simultaneously retaining strong RCSC stemness and EPCs-like characteristics. PVT1 binds with TAZ protein and prevents its phosphorylation, which promotes RCSC stemness. Moreover, RCSCs support endothelial differentiation and angiogenesis, which are mediated via the PVT1/miR-15b/KDR axis. This report provides insight into the determinants of RCSC impact on stemness and highlights the critical role of RCSC in angiogenesis. The presented findings suggest that targeting RCSC through PVT1 expression may be a new treatment strategy for ccRCC.

14-3-3-η interacts with BCL-2 to protect human endothelial progenitor cells from ox-LDL-triggered damage.

Oxidized low-density lipoprotein (ox-LDL) causes dysfunction of endothelial progenitor cells (EPCs), and we recently reported that 14-3-3-η can attenuate the damage triggered by ox-LDL in EPCs. However, the molecular mechanisms by which 14-3-3-η protects EPCs from the damage caused by ox-LDL are not fully understood. In this study, we observed that the expression of 14-3-3-η and BCL-2 were downregulated in ox-LDL-treated EPCs. Overexpression of 14-3-3-η in ox-LDL-treated EPC significantly increased BCL-2 level, while knockdown of BCL-2 reduced 14-3-3-η expression and mitigated the protective effect of 14-3-3-η on EPCs. In addition, we discovered that 14-3-3-η colocalizes and interacts with BCL-2 in EPCs. Taken together, these data suggest that 14-3-3-η protects EPCs from ox-LDL-induced damage by its interaction with BCL-2.

Retracted: Osteoprotegerin (OPG) Promotes Recruitment of Endothelial Progenitor Cells (EPCs) via CXCR4 Signaling Pathway to Improve Bone Defect Repair.

The Editors of Medical Science Monitor wish to inform you that the above manuscript has been retracted from publication due to concerns with the credibility and originality of the study, the manuscript content, and the Figure images. Reference: Rongfeng Zhang, Jianwei Liu, Shengpeng Yu, Dong Sun, Xiaohua Wang, Jingshu Fu, Jie Shen, Zhao Xie. Osteoprotegerin (OPG) Promotes Recruitment of Endothelial Progenitor Cells (EPCs) via CXCR4 Signaling Pathway to Improve Bone Defect Repair. Med Sci Monit, 2019; 25: 5572-5579. DOI: 10.12659/MSM.916838.

Responses of Endothelial Progenitor Cells to Chronic and Acute Physical Activity in Healthy Individuals.

Endothelial progenitor cells (EPCs) are circulating cells of various origins that possess the capacity for renewing and regenerating the endothelial lining of blood vessels. During physical activity, in response to factors such as hypoxia, changes in osmotic pressure, and mechanical forces, endothelial cells undergo intense physiological stress that results in endothelial damage. Circulating EPCs participate in blood vessel repair and vascular healing mainly through paracrine signalling. Furthermore, physical activity may play an important role in mobilising this important cell population. In this narrative review, we summarise the current knowledge on the biology of EPCs, including their characteristics, assessment, and mobilisation in response to both chronic and acute physical activity in healthy individuals.

Human Cord Blood Endothelial Progenitor Cells and Pregnancy Complications (Preeclampsia, Gestational Diabetes Mellitus, and Fetal Growth Restriction).

Hemangioblasts give rise to endothelial progenitor cells (EPCs), which also express the cell surface markers CD133 and c-kit. They may differentiate into the outgrowth endothelial cells (OECs) that control neovascularization in the developing embryo. According to numerous studies, reduced levels of EPCs in circulation have been linked to human cardiovascular disorders. Furthermore, preeclampsia and senescence have been linked to levels of EPCs produced from cord blood. Uncertainties surround how preeclampsia affects the way EPCs function. It is reasonable to speculate that preeclampsia may have an impact on the function of fetal EPCs during the in utero period; however, the present literature suggests that maternal vasculopathies, including preeclampsia, damage fetal circulation. Additionally, the differentiation potential and general activity of EPCs may serve as an indicator of the health of the fetal vascular system as they promote neovascularization and repair during pregnancy. Thus, the purpose of this review is to compare-through the assessment of their quantity, differentiation potency, angiogenic activity, and senescence-the angiogenic function of fetal EPCs obtained from cord blood for normal and pregnancy problems (preeclampsia, gestational diabetes mellitus, and fetal growth restriction). This will shed light on the relationship between the angiogenic function of fetal EPCs and pregnancy complications, which could have an effect on the management of long-term health issues like metabolic and cardiovascular disorders in offspring with abnormal vasculature development.

Dihydrotestosterone Augments the Angiogenic and Migratory Potential of Human Endothelial Progenitor Cells by an Androgen Receptor-Dependent Mechanism.

Endothelial progenitor cells (EPCs) play a critical role in cardiovascular regeneration. Enhancement of their native properties would be highly beneficial to ensuring the proper functioning of the cardiovascular system. As androgens have a positive effect on the cardiovascular system, we hypothesized that dihydrotestosterone (DHT) could also influence EPC-mediated repair processes. To evaluate this hypothesis, we investigated the effects of DHT on cultured human EPCs' proliferation, viability, morphology, migration, angiogenesis, gene and protein expression, and ability to integrate into cardiac tissue. The results showed that DHT at different concentrations had no cytotoxic effect on EPCs, significantly enhanced the cell proliferation and viability and induces fast, androgen-receptor-dependent formation of capillary-like structures. DHT treatment of EPCs regulated gene expression of androgen receptors and the genes and proteins involved in cell migration and angiogenesis. Importantly, DHT stimulation promoted EPC migration and the cells' ability to adhere and integrate into murine cardiac slices, suggesting it has a role in promoting tissue regeneration. Mass spectrometry analysis further highlighted the impact of DHT on EPCs' functioning. In conclusion, DHT increases the proliferation, migration, and androgen-receptor-dependent angiogenesis of EPCs; enhances the cells' secretion of key factors involved in angiogenesis; and significantly potentiates cellular integration into heart tissue. The data offer support for potential therapeutic applications of DHT in cardiovascular regeneration and repair processes.

Dysfunction of circulating endothelial progenitor cells in major depressive disorder.

OBJECTIVES: Despite mounting evidence demonstrates circulating endothelial progenitor cells (cEPCs) quantitative changes in depression, no study has investigated cEPC functions in major depressive disorder (MDD). We investigated the role of cEPC adhesive and apoptotic functions in MDD. METHODS: We recruited 68 patients with MDD and 56 healthy controls (HCs). The depression symptoms, anxiety, psychosomatic symptoms, subjective cognitive dysfunction, quality of life, and functional disability were evaluated using the Hamilton Depression Rating Scale and Montgomery-Åsberg Depression Rating Scale, Hamilton Anxiety Rating Scale, Depression and Somatic Symptoms Scale (DSSS), Perceived Deficits Questionnaire-Depression, 12-Item Short Form Health Survey (SF-12), and Sheehan Disability Scale (SDS), respectively. Working memory and executive function were assessed using a 2-back task and Wisconsin Card Sorting Test (WCST). Inflammatory marker (soluble interleukin-6 receptor, C-reactive protein, and tumor necrosis factor-α receptor-1), cEPC adhesive, and apoptotic levels were measured using in vitro assays. RESULTS: The MDD patients showed significantly lower cEPC adhesive levels than the HCs, and this difference in adhesive function remained statistically significant even after adjusting for inflammatory marker levels. The cEPC adhesion levels were in inverse correlations with commission and omission errors in 2-back task, the percent perseverative response and percent perseverative errors in WCST, and the DSSS and SDS scores, but in positive correlations with SF-12 physical and mental component scores. cEPC apoptotic levels did not differ significantly between the groups. CONCLUSION: The findings indicate that cEPC adhesive function is diminished in MDD and impacts various aspects of cognitive and psychosocial functions associated with the disorder.

Hsa-miR-409-3p regulates endothelial progenitor senescence via PP2A-P38 and is a potential ageing marker in humans.

We explored the roles of hsa-microRNA (miR)-409-3p in senescence and signalling mechanism of human endothelial progenitor cells (EPCs). Hsa-miR-409-3p was found upregulated in senescent EPCs. Overexpression of miRNA mimics in young EPCs inhibited angiogenesis. In senescent EPCs, compared to young EPCs, protein phosphatase 2A (PP2A) was downregulated, with activation of p38/JNK by phosphorylation. Young EPCs treated with siPP2A caused inhibited angiogenesis with activation of p38/JNK, similar to findings in senescent EPCs. Time series analysis showed, in young EPCs treated with hsa-miR-409-3p mimics, PP2A was steadily downregulated for 72 h, while p38/JNK was activated with a peak at 48 hours. The inhibited angiogenesis of young EPCs after miRNA-409-3p mimics treatment was reversed by the p38 inhibitor. The effect of hsa-miR-409-3p on PP2A signalling was attenuated by exogenous VEGF. Analysis of human peripheral blood mononuclear cells (PBMCs) obtained from healthy people revealed hsa-miR-409-3p expression was higher in those older than 65 years, compared to those younger than 30 years, regardless of gender. In summary, hsa-miR-409-3p was upregulated in senescent EPCs and acted as a negative modulator of angiogenesis via targeting protein phosphatase 2 catalytic subunit alpha (PPP2CA) gene and regulating PP2A/p38 signalling. Data from human PBMCs suggested hsa-miR-409-3p a potential biomarker for human ageing.

Andrographolide improves the dysfunction of endothelial progenitor cells from angiotensin II-induced hypertensive mice through SIRT1 signaling.

Endothelial progenitor cells (EPCs) are crucial for the maintenance of vascular homeostasis. The dysfunction of EPCs contributes to the endothelial damage in hypertension. Andrographolide (AGP) is a traditional Chinese patent medicine that has been reported to have protective effects on cardiovascular system. However, the effect of AGP on the function of EPCs in hypertension remains unknown. In this study, we aimed to elucidate the effect of AGP on EPCs and the underlying mechanisms. In vivo, the blood pressure and endothelial function (indicated by endothelial dependent vasodilation) of AGP-fed angiotensin II (Ang II)-infused hypertensive mice were examined. In vitro, the function of EPCs isolated from bone marrow were evaluated by tube formation, migration, and adhesion assay. Additionally, a silent information regulator 1 (SIRT1) inhibitor/agonist and a small interfering RNA (si-RNA) targeting SIRT1 were used to determine the pathway involved. The results showed that AGP not only reduced blood pressure, improved endothelial function in hypertensive mice but also restored the dysfunction of EPCs of hypertension in vitro. Mechanistically, AGP up-regulated SIRT1 expression, decreased the Bax/Bcl-2 ratio and the expression level of Cleaved caspase-3, thus inhibiting the apoptosis of Ang II induced EPCs. However, the beneficial effects of AGP on EPCs disappeared after the inhibition or the knockdown of SIRT1. To summarize, this study demonstrates for the first time that AGP improves the dysfunction of EPCs through SIRT1-mediated anti-apoptotic effects. Our findings might provide a novel therapeutic strategy for treating vascular damage in hypertension.

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.

CXCL5 suppression recovers neovascularization and accelerates wound healing in diabetes mellitus.

BACKGROUND: Higher chemokine C-X-C motif ligand 5 (CXCL5) level was observed in type 2 diabetes mellitus (DM) patients; however, its role in diabetic vasculopathy was not clarified. This study aimed to explore the impacts and mechanistic insights of CXCL5 in neovasculogenesis and wound healing in DM. METHODS: Endothelial progenitor cells (EPCs) and human aortic endothelial cells (HAECs) were used in vitro. Streptozotocin-induced diabetic mice and Leprdb/JNarl mice were used as type 1 and type 2 DM models. Moreover, CXCL5 knockout mice were used to generate diabetic mice. Hindlimb ischemia surgery, aortic ring assays, matrigel plug assay, and wound healing assay were conducted. RESULTS: CXCL5 concentrations were increased in plasma and EPCs culture medium from type 2 DM patients. CXCL5 neutralizing antibody upregulated vascular endothelial growth factor (VEGF)/stromal cell-derived factor-1 (SDF-1) and promoted cell function in EPCs from type 2 DM patients and high glucose-treated EPCs from non-DM subjects as well as HAECs. CXCL5 directly up-regulated interleukin (IL)-1ß/IL-6/tumor necrosis factor-α and down-regulated VEGF/SDF-1 via ERK/p65 activation through chemokine C-X-C motif receptor 2 (CXCR2). CXCL5 neutralizing antibody recovered the blood flow after hindlimb ischemia, increased circulating EPC number, and enhanced VEGF and SDF-1 expression in ischemic muscle. CXCL5 suppression promoted neovascularization and wound healing in different diabetic animal models. The above observation could also be seen in streptozotocin-induced CXCL5 knockout diabetic mice. CONCLUSIONS: CXCL5 suppression could improve neovascularization and wound healing through CXCR2 in DM. CXCL5 may be regarded as a potential therapeutic target for vascular complications of DM.

Adenosine promoted angiogenesis mediated by the release of small extracellular vesicles from human endothelial progenitor cells.

Endothelial progenitor cells (EPCs) are stem cells mainly derived from bone marrow; from where they migrate to repair and regenerate damaged tissues. eEPCs have been classified into two sub-populations, early (eEPC) and late EPCs (lEPC), depending on maturation stages in vitro. In addition, eEPC release endocrine mediators, including small extracellular vesicles (sEVs), which in turn may enhance the eEPC-mediated wound healing properties. Nevertheless, adenosine contributes to angiogenesis by recruiting eEPC at the injury site. However, whether ARs may enhance the secretome of eEPC, including sEVs, is unknown. Therefore, we aimed to investigate whether AR activation increase the release of sEVs in eEPC, which in turn has paracrine effects on recipient endothelial cells. Results shown that 5'-N-ethylcarboxamidoadenosine (NECA), a non-selective agonist, increase both the protein levels of the vascular endothelial growth factor (VEGF), and the number of sEVs released to the conditioned medium (CM) in primary culture of eEPC. Importantly, CM and EVs harvested from NECA-stimulated eEPC promote in vitro angiogenesis, without changes in cell proliferation, in recipient ECV-304 endothelial cells. This constitutes the first evidence showing that adenosine enhances sEVs release from eEPC, which has pro-angiogenic capacity on recipient endothelial cells.

IL-10 promotes endothelial progenitor cell infiltration and wound healing via STAT3.

Endothelial progenitor cells (EPCs) contribute to de novo angiogenesis, tissue regeneration, and remodeling. Interleukin 10 (IL-10), an anti-inflammatory cytokine that primarily signals via STAT3, has been shown to drive EPC recruitment to injured tissues. Our previous work demonstrated that overexpression of IL-10 in dermal wounds promotes regenerative tissue repair via STAT3-dependent regulation of fibroblast-specific hyaluronan synthesis. However, IL-10's role and specific mode of action on EPC recruitment, particularly in dermal wound healing and neovascularization in both normal and diabetic wounds, remain to be defined. Therefore, inducible skin-specific STAT3 knockdown mice were studied to determine IL-10's impact on EPCs, dermal wound neovascularization and healing, and whether it is STAT3-dependent. We show that IL-10 overexpression significantly elevated EPC counts in the granulating wound bed, which was associated with robust capillary lumen density and enhanced re-epithelialization of both control and diabetic (db/db) wounds at day 7. We noted increased VEGF and high C-X-C motif chemokine 12 (CXCL12) levels in wounds and a favorable CXCL12 gradient at day 3 that may support EPC mobilization and infiltration from bone marrow to wounds, an effect that was abrogated in STAT3 knockdown wounds. These findings were supported in vitro. IL-10 promoted VEGF and CXCL12 synthesis in primary murine dermal fibroblasts, with blunted VEGF expression upon blocking CXCL12 in the media by antibody binding. IL-10-conditioned fibroblast media also significantly promoted endothelial sprouting and network formation. In conclusion, these studies demonstrate that overexpression of IL-10 in dermal wounds recruits EPCs and leads to increased vascular structures and faster re-epithelialization.

Downregulation of miR-1270 mediates endothelial progenitor cell function in preeclampsia: Role for ATM in the Src/VE-cadherin axis.

Preeclampsia, a pregnancy-related hypertensive disorder, is associated with endothelial dysfunction and increased cardiovascular risk of the offspring in adulthood. In preeclampsia, endothelial colony-forming cells (ECFC) are reduced in number and function. Recently, we have shown that miR-1270, which is involved in cancer in vitro proliferation, migration, and tumor progression, is downregulated in fetal ECFC from preeclamptic pregnancies. We now hypothesize that miR-1270 dysregulation contributes to vascular endothelial dysfunction occurring after preeclampsia via ATM (ataxia telangiectasia mutated) overexpression, the key kinase of DNA damage repair. Here, we show that miR-1270 silencing in normal ECFC and downregulation in preeclamptic ECFC are accompanied by an increase in the expression levels of ATM. Furthermore, ATM activation correlates with upregulated tyrosine kinase Src leading to phosphorylation and internalization of VE-cadherin (vascular endothelial-cadherin) which subsequently compromises endothelial barrier permeability and morphodynamic cell parameters. Treatment with specific ATM inhibitors reveals a novel role of ATM upstream of tyrosine kinase Src activation. Subsequently, Src phosphorylation and internalization of VE-cadherin compromise endothelial barrier permeability. Our findings suggest that downregulation of miR-1270 contributes to impaired ECFC function via the associated ATM overexpression, which further identifies ATM as a novel and critical factor for ECFC defects in preeclampsia. Our study provides new insights into the understanding of ECFC impairment associated with cardiovascular risk in preeclamptic offspring and identifies potential novel therapeutic targets.