Cerebral aneurysm (CA) is a significant health concern that results from pathological dilations of blood vessels in the brain and can lead to severe and potentially life-threatening conditions. While the pathogenesis of CA is complex, emerging studies suggest that endothelial progenitor cells (EPCs) play a crucial role. In this paper, we conducted a comprehensive literature review to investigate the potential role of EPCs in the pathogenesis and treatment of CA. Current research indicates that a decreased count and dysfunction of EPCs disrupt the balance between endothelial dysfunction and repair, thus increasing the risk of CA formation. Reversing these EPCs abnormalities may reduce the progression of vascular degeneration after aneurysm induction, indicating EPCs as a promising target for developing new therapeutic strategies to facilitate CA repair. This has motivated researchers to develop novel treatment options, including drug applications, endovascular-combined and tissue engineering therapies. Although preclinical studies have shown promising results, there is still a considerable way to go before clinical translation and eventual benefits for patients. Nonetheless, these findings offer hope for improving the treatment and management of this condition.

Endothelial progenitor cells (EPCs) play a crucial role in maintaining vascular health and aiding in the repair of damaged blood vessels. However, the specific impact of EPCs-derived exosomes on vascular endothelial cell injury caused by lipopolysaccharide (LPS) remains inadequately understood. This study aims to explore the potential benefits of EPC-exosomes in mitigating LPS-induced vascular injury and to elucidate the underlying mechanism. Initially, EPCs were isolated from mouse peripheral blood, and their identity was confirmed through flow cytometry and immunocytochemistry. Subsequently, the exosomes derived from EPCs were identified using transmission electron microscopy (TEM) and western blot analysis. A sepsis model was induced by subjecting brain microvascular endothelial cells (BMECs) to LPS-induced injury. Both EPC and their exosomes demonstrated a significant increase in BMECs proliferation, reduced apoptosis, decreased levels of pro-inflammatory factors (TNF-α, IL-6, and caspase-3), and enhanced sprouting and angiogenesis of BMECs. Notable, the Exosomes demonstrated a more pronounced impact on these parameters. Furthermore, both EPCs and Exosomes exhibited significantly increased levels of miR-126a-5p, with the Exosomes showing a more substantial enhancement. These findings suggest that supplementing exosomal miR-126a-5p from EPCs can provide protective effects on BMECs, offering a potential therapeutic option for treating sepsis-induced microvascular endothelial cell injury.

UNASSIGNED: Venous leg ulcers (VLUs) are prevalent chronic wounds with limited treatment options. This study aimed to investigate the potential of berberine to enhance endothelial progenitor cell (EPC) function in VLU healing.
UNASSIGNED: Histopathological changes and inflammatory cytokine levels in a deep venous thrombosis (DVT) mouse model were assessed using HE staining and ELISA assays. A luciferase reporter assay was employed to identify the miR-21-3p and RRAGB targeting relationship. EPC proliferation, migration, and tube formation were evaluated through CCK-8, Transwell, and tubule formation assays, while the mTOR pathway and autophagy-related proteins were analyzed by immunofluorescence staining and western blotting.
UNASSIGNED: Berberine significantly improved EPC functions, such as proliferation, migration, and tube formation in vitro, and enhanced in vivo EPC-mediated wound healing in a DVT mouse model. Furthermore, miR-21-3p was downregulated in EPCs from VLU patients, and its overexpression improved model EPC functions. Mechanistically, RRAGB, which regulates the mTOR pathway, was identified as a potential miR-21-3p target in EPCs. Overexpression of RRAGB inhibited autophagic activity and impaired EPC function.
UNASSIGNED: Berberine shows promise in ameliorating EPC function and promoting wound healing in VLUs. The regulation of the miR-21-3p/RRAGB axis by berberine could offer a promising therapeutic approach for managing VLUs.

Delta like non-canonical Notch ligand 1 (DLK1), as a member of epidermal growth factor-like family, plays a critical role in somatic growth, tissue development and possibly tissue renewal. Though previous studies had indicated that DLK1 contributed to adipogenesis and myogenesis, it\'s still controversial whether DLK1 affects angiogenesis and how it interacts with Notch signaling with numerous conflicting reports from different models. Based on our preliminary finding that DLK1 expression was up-regulated in mice ischemic gastrocnemius and in the border zone of infarcted myocardium, we administered either recombinant DLK1 (rDLK1) or PBS in C57BL/6 mice after establishment of hindlimb ischemia (HLI) and myocardial infarction (MI), respectively. Exogenous rDLK1 administration significantly improved both blood perfusion of mice ischemic hindlimbs and muscle motor function on the 3rd, 7th day after HLI, by promoting neovascularization. Similar effect on neovascularization was verified in mice on the 28th day after MI as well as improvement of cardiac failure. Correspondingly, the number of CD34+KDR+ cells, indicated as endothelial progenitor cells (EPCs), was significantly in mice ischemic gastrocnemius by rDLK1 administration, which was abrogated by DAPT as the specific inhibitor of Notch intracellular domain (NICD). Furthermore, bone marrow mononuclear cells were obtained from C57BL/6 mice and differentiated to EPCs ex vivo. Incubation with rDLK1 triggered Notch1 mRNA and NICD protein expressions in EPCs as exposed to hypoxia and serum deprivation, promoting EPCs proliferation, migration, anti-apoptosis and tube formation. Otherwise, rDLK1 incubation significantly decreased intracellular and mitochondrial reactive oxygen species, increased ATP content and mitochondrial membrane potential, downregulated short isoform of OPA-1 expression whereas upregulated mitofusin (-1, -2) expression in EPCs by Notch1 signaling, which were all abrogated by DAPT. In summary, the present study unveils the pro-angiogenesis and its mechanism of rDLK1 through activation of Notch1 signaling in endothelial progenitor cells.

OBJECTIVE: Endothelial progenitor cells (EPCs) play a crucial role in acquired angiogenesis and endothelial injury repair. Transient receptor potential canonical channel 4 (TRPC4), a key component of store-operated calcium channels, is essential for EPC function. While the role of TRPCs has been clarified in vascular diseases, the relationship between TRPC4 and EPC function, along with the underlying molecular mechanisms, remains unclear and requires further elucidation.
METHODS: EPCs were isolated from canine bone marrow and identified by morphology and flow cytometry. TRPC4 was transfected into EPCs using lentivirus or negative control, and its expression was assessed using real-time polymerase chain reaction (RT-PCR). Proliferation, migration, and tube formation were evaluated using Cell Counting Kit-8 (CCK-8), Transwell, and Matrigel assays, respectively. Levels of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) were measured using enzyme-linked immunosorbent assay (ELISA).
RESULTS: TRPC4 mRNA expression was significantly reduced in TRPC4-short hairpin RNA (shRNA) transfected EPCs compared to the normal control (NC)-shRNA groups. Migration and tube formation were significantly decreased after TRPC4 silencing, while proliferation showed no difference. Additionally, levels of SDF-1 and VEGF in EPCs were markedly reduced following TRPC4 silencing.
CONCLUSIONS: TRPC4 plays a crucial role in regulating angiogenesis in EPCs. Silencing of TRPC4 can lead to decreased angiogenesis by inhibiting VEGF and SDF-1 expression, suggesting that TRPC4 knockdown might be a novel therapeutic strategy for vascular diseases.

The treatment of osteoporotic bone defects poses a challenge due to the degradation of the skeletal vascular system and the disruption of local bone metabolism within the osteoporotic microenvironment. However, it is feasible to modulate the disrupted local bone metabolism imbalance through enhanced vascularization, a theory termed \"vascularization-bone metabolic balance\". This study developed a 3D-printed polycaprolactone (PCL) scaffold modified with EPLQLKM and SVVYGLR peptides (PCL-SE). The EPLQLKM peptide attracts bone marrow-derived mesenchymal stem cells (BMSCs), while the SVVYGLR peptide enhances endothelial progenitor cells (EPCs) vascular differentiation, thus regulating bone metabolism and fostering bone regeneration through the paracrine effects of EPCs. Further mechanistic research demonstrated that PCL-SE promoted the vascularization of EPCs, activating the Notch signaling pathway in BMSCs, leading to the upregulation of osteogenesis-related genes and the downregulation of osteoclast-related genes, thereby restoring bone metabolic balance. Furthermore, PCL-SE facilitated the differentiation of EPCs into \"H\"-type vessels and the recruitment of BMSCs to synergistically enhance osteogenesis, resulting in the regeneration of normal microvessels and bone tissues in cases of femoral condylar bone defects in osteoporotic SD rats. This study suggests that PCL-SE supports in-situ vascularization, remodels bone metabolic translational balance, and offers a promising therapeutic regimen for osteoporotic bone defects.

UNASSIGNED: Cerebral vascular malformations (CCMs) are primarily found within the brain, where they result in increased risk for stroke, seizures, and focal neurological deficits. The unique feature of the brain vasculature is the blood-brain barrier formed by the brain neurovascular unit. Recent studies suggest that loss of CCM genes causes disruptions of blood-brain barrier integrity as the inciting events for CCM development. CCM lesions are proposed to be initially derived from a single clonal expansion of a subset of angiogenic venous capillary endothelial cells (ECs) and respective resident endothelial progenitor cells (EPCs). However, the critical signaling events in the subclass of brain ECs/EPCs for CCM lesion initiation and progression are unclear.
UNASSIGNED: Brain EC-specific CCM3-deficient (Pdcd10BECKO) mice were generated by crossing Pdcd10fl/fl mice with Mfsd2a-CreERT2 mice. Single-cell RNA-sequencing analyses were performed by the chromium single-cell platform (10× genomics). Cell clusters were annotated into EC subtypes based on visual inspection and GO analyses. Cerebral vessels were visualized by 2-photon in vivo imaging and tissue immunofluorescence analyses. Regulation of mTOR (mechanistic target of rapamycin) signaling by CCM3 and Cav1 (caveolin-1) was performed by cell biology and biochemical approaches.
UNASSIGNED: Single-cell RNA-sequencing analyses from P10 Pdcd10BECKO mice harboring visible CCM lesions identified upregulated CCM lesion signature and mitotic EC clusters but decreased blood-brain barrier-associated EC clusters. However, a unique EPC cluster with high expression levels of stem cell markers enriched with mTOR signaling was identified from early stages of the P6 Pdcd10BECKO brain. Indeed, mTOR signaling was upregulated in both mouse and human CCM lesions. Genetic deficiency of Raptor (regulatory-associated protein of mTOR), but not of Rictor (rapamycin-insensitive companion of mTOR), prevented CCM lesion formation in the Pdcd10BECKO model. Importantly, the mTORC1 (mTOR complex 1) pharmacological inhibitor rapamycin suppressed EPC proliferation and ameliorated CCM pathogenesis in Pdcd10BECKO mice. Mechanistic studies suggested that Cav1/caveolae increased in CCM3-depleted EPC-mediated intracellular trafficking and complex formation of the mTORC1 signaling proteins.
UNASSIGNED: CCM3 is critical for maintaining blood-brain barrier integrity and CCM3 loss-induced mTORC1 signaling in brain EPCs initiates and facilitates CCM pathogenesis.

BACKGROUND: Peripheral artery disease (PAD) is an ischemic disease with a rising incidence worldwide. The lncRNA H19 (H19) is enriched in endothelial progenitor cells (EPCs), and transplantation of pyroptosis-resistant H19-overexpressed EPCs (oe-H19-EPCs) may promote vasculogenesis and blood flow recovery in PAD, especially with critical limb ischemia (CLI).
METHODS: EPCs isolated from human peripheral blood was characterized using immunofluorescence and flow cytometry. Cell proliferation was determined with CCK8 and EdU assays. Cell migration was assessed by Transwell and wound healing assays. The angiogenic potential was evaluated using tube formation assay. The pyroptosis pathway-related protein in EPCs was detected by western blot. The binding sites of H19 and FADD on miR-107 were analyzed using Luciferase assays. In vivo, oe-H19-EPCs were transplanted into a mouse ischemic limb model, and blood flow was detected by laser Doppler imaging. The transcriptional landscape behind the therapeutic effects of oe-H19-EPCs on ischemic limbs were examined with whole transcriptome sequencing.
RESULTS: Overexpression of H19 in EPCs led to an increase in proliferation, migration, and tube formation abilities. These effects were mediated through pyroptosis pathway, which is regulated by the H19/miR-107/FADD axis. Transplantation of oe-H19-EPCs in a mouse ischemic limb model promoted vasculogenesis and blood flow recovery. Whole transcriptome sequencing indicated significant activation of vasculogenesis pathway in the ischemic limbs following treatment with oe-H19-EPCs.
CONCLUSIONS: Overexpression of H19 increases FADD level by competitively binding to miR-107, leading to enhanced proliferation, migration, vasculogenesis, and inhibition of pyroptosis in EPCs. These effects ultimately promote the recovery of blood flow in CLI.

BACKGROUND: The transplantation of endothelial progenitor cells (EPCs) has been shown to reduce neointimal hyperplasia following arterial injury. However, the efficacy of this approach is hampered by limited homing of EPCs to the injury site. Additionally, the in vivo recruitment and metabolic activity of transplanted EPCs have not been continuously monitored.
METHODS: EPCs were labeled with indocyanine green (ICG)-conjugated superparamagnetic iron oxide nanoparticles (SPIONs) and subjected to external magnetic field targeting to enhance their delivery to a carotid balloon injury (BI) model in Sprague-Dawley rats. Magnetic particle imaging (MPI)/ fluorescence imaging (FLI) multimodal in vivo imaging, 3D MPI/CT imaging and MPI/FLI ex vivo imaging was performed after injury. Carotid arteries were collected and analyzed for pathology and immunofluorescence staining. The paracrine effects were analyzed by enzyme-linked immunosorbent assay.
RESULTS: The application of a magnetic field significantly enhanced the localization and retention of SPIONs@PEG-ICG-EPCs at the site of arterial injury, as evidenced by both in vivo continuous monitoring and ex vivo by observation. This targeted delivery approach effectively inhibited neointimal hyperplasia and increased the presence of CD31-positive cells at the injury site. Moreover, serum levels of SDF-1α, VEGF, IGF-1, and TGF-β1 were significantly elevated, indicating enhanced paracrine activity.
CONCLUSIONS: Our findings demonstrate that external magnetic field-directed delivery of SPIONs@PEG-ICG-EPCs to areas of arterial injury can significantly enhance their therapeutic efficacy. This enhancement is likely mediated through increased paracrine signaling. These results underscore the potential of magnetically guided SPIONs@PEG-ICG-EPCs delivery as a promising strategy for treating arterial injuries.

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.