Production of the Cytokine VEGF-A by CD4+ T and Myeloid Cells Disrupts the Corneal Nerve Landscape and Promotes Herpes Stromal Keratitis.

Herpes simplex virus type 1 (HSV-1)-infected corneas can develop a blinding immunoinflammatory condition called herpes stromal keratitis (HSK), which involves the loss of corneal sensitivity due to retraction of sensory nerves and subsequent hyperinnervation with sympathetic nerves. Increased concentrations of the cytokine VEGF-A in the cornea are associated with HSK severity. Here, we examined the impact of VEGF-A on neurologic changes that underly HSK using a mouse model of HSV-1 corneal infection. Both CD4+ T cells and myeloid cells produced pathogenic levels of VEGF-A within HSV-1-infected corneas, and CD4+ cell depletion promoted reinnervation of HSK corneas with sensory nerves. In vitro, VEGF-A from infected corneas repressed sensory nerve growth and promoted sympathetic nerve growth. Neutralizing VEGF-A in vivo using bevacizumab inhibited sympathetic innervation, promoted sensory nerve regeneration, and alleviated disease. Thus, VEGF-A can shape the sensory and sympathetic nerve landscape within the cornea, with implications for the treatment of blinding corneal disease.

Svep1 stabilises developmental vascular anastomosis in reduced flow conditions.

Molecular mechanisms controlling the formation, stabilisation and maintenance of blood vessel connections remain poorly defined. Here, we identify blood flow and the large extracellular protein Svep1 as co-modulators of vessel anastomosis during developmental angiogenesis in zebrafish embryos. Both loss of Svep1 and blood flow reduction contribute to defective anastomosis of intersegmental vessels. The reduced formation and lumenisation of the dorsal longitudinal anastomotic vessel (DLAV) is associated with a compensatory increase in Vegfa/Vegfr pERK signalling, concomittant expansion of apelin-positive tip cells, but reduced expression of klf2a. Experimentally, further increasing Vegfa/Vegfr signalling can rescue the DLAV formation and lumenisation defects, whereas its inhibition dramatically exacerbates the loss of connectivity. Mechanistically, our results suggest that flow and Svep1 co-regulate the stabilisation of vascular connections, in part by modulating the Vegfa/Vegfr signalling pathway.

Upregulation of circ-IGF1R increased therapeutic effect of hypoxia-pretreated ADSC-derived extracellular vesicle by regulating miR-503-5p/HK2/VEGFA axis.

Diabetes mellitus is a major cause of blindness and chronic ulcers in the working-age population worldwide. Wound healing is deeply dependent on neovascularization to restore blood flow. Former research has found that differentially expressed circular RNAs (circRNAs) are associated with hyperglycaemia-induced endothelial cell damage, and hypoxia-pretreated adipose-derived stem cells (ADSCs)-extracellular vesicle (HEV) transplants have a more therapeutic effect to enhance wound healing in diabetic mice by delivery circRNA. The current investigation employed high-throughput sequencing to identify circRNAs that are abnormally expressed between EV and HEV. The regulatory mechanism and predicted targets of one differentially expressed circRNA, circ-IGF1R, were investigated utilizing bioinformatics analyses, luciferase reporter assays, angiogenic differentiation assays, flow cytometric apoptosis analysis and RT-qPCR. Circ-IGF1R expression increased in HEV, and downregulation of circ-IGF1R suppressed and reversed the promotion effect of HEV on angiogenesis in ulcerated tissue. Bioinformatics analyses and luciferase reporter assays confirmed that miR-503-5p was the downstream target of circ-IGF1R, and inhibiting miR-503-5p restored the promotion effect of HEV on angiogenesis after circ-IGF1R silence. The study also found that miR-503-5p can interact with 3'-UTR of both HK2 and VEGFA. Overexpression of HK2 or VEGFA restored the promotion effect of HExo on angiogenesis after circ-IGF1R silence. Overexpression miR-503-5p or silence HK2/VEGFA reversed the protective effect of circ-IGF1R to MLMECs angiogenic differentiation. Overexpression of circ-IGF1R increased the protective effect of HEV on the promotion of wound healing in mice with diabetes. Circ-IGF1R promotes HIF-1α expression through miR-503-5p sponging. Our data demonstrate that circ-IGF1R overexpression EVs from ADSCs suppress high glucose-induced endothelial cell damage by regulating miR-503-5p/HK2/VEGFA axis.

Serine/threonine-protein kinase STK24 induces tumorigenesis by regulating the STAT3/VEGFA signaling pathway.

Lung cancer is the most common cause of cancer-related death. Although anti-angiogenesis therapy has been effective in the treatment of nonsmall cell lung cancer (NSCLC), drug-resistance is a common challenge. Therefore, there is a need to develop new therapeutic strategies for NSCLC. Serine/threonine-protein kinase 24 (STK24), also known as MST3, belongs to the germinal center kinase III subfamily, and the biological function of STK24 in NSCLC tumorigenesis and tumor angiogenesis is still unclear. In this study, we demonstrated that STK24 was overexpressed in lung cancer tissues compared with normal lung tissues, and lung cancer patients with higher STK24 expression levels had shorter overall survival time. In addition, our in vitro assays using A549 and H226 cell lines revealed that the STK24 expression level of cancer cells was positively correlated with cancer cells proliferation, migration, invasion, and tumor angiogenesis ability; in vivo assays also demonstrated that silencing of STK24 dramatically inhibited tumor progress and tumor angiogenesis. To investigate a mechanism, we revealed that STK24 positively regulated the signal transducer and activator of transcription 3 (STAT3)/vascular endothelial growth factor A (VEGFA) signaling pathway by inhibiting polyubiquitin-proteasomal-mediated degradation of STAT3. Furthermore, we performed in vivo assays in BALB/c nude mice and in vitro assays to show that STK24-regulated tumor angiogenesis depends on STAT3. These findings deepened our understanding of tumor angiogenesis, and the STK24/STAT3/VEGFA signaling pathway might be a novel therapeutic target for NSCLC treatment.

ILT4 facilitates angiogenesis in non-small cell lung cancer.

Antiangiogenic therapy targeting VEGF-A has become the standard of first-line therapy for non-small cell lung cancer (NSCLC). However, its clinical response rate is still less than 50%, and most patients eventually develop resistance, even when using combination therapy with chemotherapy. The major cause of resistance is the activation of complex bypass signals that induce angiogenesis and tumor progression. Therefore, exploring novel proangiogenic mechanisms and developing promising targets for combination therapy are crucial for improving the efficacy of antiangiogenic therapy. Immunoglobulin-like transcript (ILT) 4 is a classic immunosuppressive molecule that inhibits myeloid cell activation. Recent studies have shown that tumor cell-derived ILT4 drives tumor progression via the induction of malignant biologies and creation of an immunosuppressive microenvironment. However, whether and how ILT4 participates in NSCLC angiogenesis remain elusive. Herein, we found that enriched ILT4 in NSCLC is positively correlated with high microvessel density, advanced disease, and poor overall survival. Tumor cell-derived ILT4 induced angiogenesis both in vitro and in vivo and tumor progression and metastasis in vivo. Mechanistically, ILT4 was upregulated by its ligand angiopoietin-like protein 2 (ANGPTL2). Their interaction subsequently activated the ERK1/2 signaling pathway to increase the secretion of the proangiogenic factors VEGF-A and MMP-9, which are responsible for NSCLC angiogenesis. Our study explored a novel mechanism for ILT4-induced tumor progression and provided a potential target for antiangiogenic therapy in NSCLC.

VEGF-A plasma levels are associated with impaired DLCO and radiological sequelae in long COVID patients.

BACKGROUND: Long COVID, also known as post-acute sequelae of COVID-19 (PASC), is characterized by persistent clinical symptoms following COVID-19. OBJECTIVE: To correlate biomarkers of endothelial dysfunction with persistent clinical symptoms and pulmonary function defects at distance from COVID-19. METHODS: Consecutive patients with long COVID-19 suspicion were enrolled. A panel of endothelial biomarkers was measured in each patient during clinical evaluation and pulmonary function test (PFT). RESULTS: The study included 137 PASC patients, mostly male (68%), with a median age of 55 years. A total of 194 PFTs were performed between months 3 and 24 after an episode of SARS-CoV-2 infection. We compared biomarkers evaluated in PASC patients with 20 healthy volunteers (HVs) and acute hospitalized COVID-19 patients (n = 88). The study found that angiogenesis-related biomarkers and von Willebrand factor (VWF) levels were increased in PASC patients compared to HVs without increased inflammatory or platelet activation markers. Moreover, VEGF-A and VWF were associated with persistent lung CT scan lesions and impaired diffusing capacity of the lungs for carbon monoxide (DLCO) measurement. By employing a Cox proportional hazards model adjusted for age, sex, and body mass index, we further confirmed the accuracy of VEGF-A and VWF. Following adjustment, VEGF-A emerged as the most significant predictive factor associated with persistent lung CT scan lesions and impaired DLCO measurement. CONCLUSION: VEGF-A is a relevant predictive factor for DLCO impairment and radiological sequelae in PASC. Beyond being a biomarker, we hypothesize that the persistence of angiogenic disorders may contribute to long COVID symptoms.

Balance of Gata3 and Ramp2 in hepatocytes regulates hepatic vascular reconstitution in postoperative liver regeneration.

BACKGROUND & AIMS: Post-hepatectomy liver failure (PHLF) leads to poor prognosis in patients undergoing hepatectomy, with hepatic vascular reconstitution playing a critical role. However, the regulators of hepatic vascular reconstitution remain unclear. In this study, we aimed to investigate the regulatory mechanisms of hepatic vascular reconstitution and identify biomarkers predicting PHLF in patients undergoing hepatectomy. METHODS: Candidate genes that were associated with hepatic vascular reconstitution were screened using adeno-associated virus vectors in Alb-Cre-CRISPR/Cas9 mice subjected to partial hepatectomy. The biological activities of candidate genes were estimated using endothelial precursor transfusion and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) models. The level of candidates was detected in biopsies from patients undergoing ALPPS. Risk factors for PHLF were also screened using retrospective data. RESULTS: Downregulation of Gata3 and upregulation of Ramp2 in hepatocytes promoted the proliferation of liver sinusoidal endothelial cells and hepatic revascularization. Pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor A (VEGFA) played opposite roles in regulating the migration of endothelial precursors from bone marrow and the formation of new sinusoids after hepatectomy. Gata3 restricted endothelial cell function in patient-derived hepatic organoids, which was abrogated by a Gata3 inhibitor. Moreover, overexpression of Gata3 led to higher mortality in ALPPS mice, which was improved by a PEDF-neutralizing antibody. The expression of Gata3/RAMP and PEDF/VEGFA tended to have a negative correlation in patients undergoing ALPPS. A nomogram incorporating multiple factors, such as serum PEDF/VEGF index, was constructed and could efficiently predict the risk of PHLF. CONCLUSIONS: The balance of Gata3 and Ramp2 in hepatocytes regulates the proliferation of liver sinusoidal endothelial cells and hepatic revascularization via changes in the expression of PEDF and VEGFA, revealing potential targets for the prevention and treatment of PHLF. IMPACT AND IMPLICATIONS: In this study, we show that the balance of Gata3 and Ramp2 in hepatocytes regulates hepatic vascular reconstitution by promoting a shift from pigment epithelium-derived factor (PEDF) to vascular endothelial growth factor A (VEGFA) expression during hepatectomy- or ALLPS (associating liver partition and portal vein ligation for staged hepatectomy)-induced liver regeneration. We also identified serum PEDF/VEGFA index as a potential predictor of post-hepatectomy liver failure in patients who underwent hepatectomy. This study improves our understanding of how hepatocytes contribute to liver regeneration and provides new targets for the prevention and treatment of post-hepatectomy liver failure.

VEGF-A controls the expression of its regulator of angiogenic functions, dopamine D2 receptor, on endothelial cells.

We have previously demonstrated significant upregulation of dopamine D2 (DAD2) receptor (DRD2) expression on tumor endothelial cells. The dopamine D2 receptors, upon activation, inhibit the proangiogenic actions of vascular endothelial growth factor-A (VEGF-A, also known as vascular permeability factor). Interestingly, unlike tumor endothelial cells, normal endothelial cells exhibit very low to no expression of dopamine D2 receptors. Here, for the first time, we demonstrate that through paracrine signaling, VEGF-A can control the expression of dopamine D2 receptors on endothelial cells via Krüppel-like factor 11 (KLF11)-extracellular signal-regulated kinase (ERK) 1/2 pathway. These results thus reveal a novel bidirectional communication between VEGF-A and DAD2 receptors.

Prospective Observational Study of Ramucirumab Plus Docetaxel After Combined Chemoimmunotherapy in Patients With Non-Small-Cell Lung Cancer.

BACKGROUND: A history of pre-administration of immune checkpoint inhibitors has been reported to be associated with good outcomes of ramucirumab (RAM) plus docetaxel (DOC) combination therapy for advanced non-small-cell lung cancer (NSCLC). However, existing knowledge on the clinical significance of RAM and DOC following combined chemoimmunotherapy is limited. Therefore, we evaluated the efficacy and safety of RAM plus DOC therapy after combined chemoimmunotherapy and attempted to identify the predictors of its outcomes. PATIENTS AND METHODS: This multicenter, prospective study investigated the efficacy and safety of RAM plus DOC after combined chemoimmunotherapy. The primary endpoint was progression-free survival (PFS). Secondary endpoints were the objective response rate (ORR), disease control rate (DCR), overall survival (OS), and incidence of adverse events. An exploratory analysis measured serum cytokine levels at the start of treatment. RESULTS: Overall, 44 patients were enrolled from 10 Japanese institutions between April 2020 and June 2022. The median PFS and OS were 6.3 and 22.6 months, respectively. Furthermore, the ORR and DCR were 36.4% and 72.7%, respectively. The high vascular endothelial growth factor D (VEGF-D) group had a significantly shorter PFS and OS. A combination of high VEGF-A and low VEGF-D levels was associated with a longer PFS. CONCLUSION: Our results showed that RAM plus DOC after combined chemoimmunotherapy might be an effective and relatively feasible second-line treatment for patients with advanced NSCLC in a real-world setting.

MicroRNA-299-3p inhibits cell proliferation, motility, invasion and angiogenesis via VEGFA in upper tract urothelial carcinoma.

BACKGROUND: Upper tract urothelial carcinoma (UTUC) is a rare tumor with extraordinarily different features between Eastern and Western countries. Vascular endothelial growth factor-A (VEGFA) was originally identified as a secreted signaling protein and regulator of vascular development and cancer progression. In this study, we aimed to elucidate the molecular mechanisms underlying the regulation of VEGFA by microRNA in UTUC. METHODS: VEGFA expression was evaluated by immunohistochemistry in 140 human UTUC tissue samples. Next, we assessed the regulatory relationship between VEGFA and miR-299-3p by real-time PCR, western blotting, ELISA and dual-luciferase reporter assays using two UTUC cell lines. The role of miR-299-3p/VEGFA in cell proliferation, motility, invasion, and tube formation was analyzed in vitro. RESULTS: High VEGFA expression was significantly associated with tumor stage, grade, distant metastasis and cancer-related death and correlated with poor progression-free and cancer-specific survival. VEGFA knockdown repressed proliferation, migration, invasion and angiogenesis in UTUC cell lines. miR-299-3p significantly reduced VEGFA protein expression and miR-299-3p overexpression inhibited VEGFA mRNA and protein expression by directly targeting its 3'-UTR. Functional studies indicated that VEGFA overexpression reversed the miR-299-3p-mediated suppression of tumor cell proliferation, migration, invasion and angiogenesis. In addition, miR-299-3p/VEGFA suppressed cellular functions in UTUC by modulating the expression of P18 and cyclin E2. CONCLUSIONS: Our findings suggest that miR-299-3p possibly suppresses UTUC cell proliferation, motility, invasion and angiogenesis via VEGFA. VEGFA may act as a prognostic predictor, and both VEGFA and miR-299-3p could be potential therapeutic targets for UTUC.

Overexpression of VEGFA mediated by HIF-1 is associated with higher rate of spread through air spaces in resected lung adenocarcinomas.

BACKGROUND: Spread through air spaces (STAS), a newly identified pattern of invasion in lung adenocarcinomas (LACs), is an unfavorable prognostic factor for patients with LAC, but the molecular characteristics and mechanisms underlying STAS have not been adequately explored. METHODS: In total, 650 pathologically confirmed invasive LAC patients who underwent curative resection between December 2019 and April 2020 were reviewed. Disease-free survival (DFS) and overall survival (OS) were analyzed using the log-rank test and the Cox proportional hazards model. A comparative deep sequencing analysis was conducted to explore the molecular characteristics underlying STAS. Vascular endothelial growth factor A (VEGFA) expression was evaluated by immunoblotting and immunohistochemical analysis using fresh tumor tissue and tissue microarray. RESULTS: STAS was more prevalent in patients with a smoking history (p < 0.001), high pathological TNM stage (p < 0.001), lymphovascular invasion (p < 0.001), visceral pleural invasion (p < 0.001) and micropapillary/solid histological subtypes (p < 0.001). STAS-negative patients had better DFS (p < 0.001) and OS (p = 0.003) compared to STAS-positive patients with invasive LACs, especially in the lymph node-negative population (p < 0.001). After RNA-sequencing analysis, hypoxia-inducible factor-1 (HIF-1) signaling was enriched and appeared to be strongly correlated with STAS, and more STAS-positive individuals were detected in the higher VEGFA-expressing group (p = 0.042). CONCLUSIONS: We demonstrated that STAS was an independent prognostic marker of poor clinical outcome, especially in lymph node-negative patients, and that higher VEGFA expression mediated by HIF-1 signaling was associated with an increased STAS rate.

Polyene phosphatidylcholine promotes tibial fracture healing in rats by stimulating angiogenesis dominated by the VEGFA/VEGFR2 signaling pathway.

One of the factors that predispose to fractures is liver damage. Interestingly, fractures are sometimes accompanied by abnormal liver function. Polyene phosphatidylcholine (PPC) is an important liver repair drug. We wondered if PPC had a role in promoting fracture healing. A rat model of tibial fracture was developed using the modified Einhorn model method. X-rays were used to detect the progression of fracture healing. Progress of ossification and angiogenesis at the fracture site were analyzed by Safranin O/fast green staining and CD31 immunohistochemistry. To investigate whether PPC has a direct angiogenesis effect, HUVECs were used. We performed MTT, wound healing, Transwell migration, and tube formation assays. Finally, RT-qPCR and Western blot analysis were used to study the underlying mechanism. The results showed that PPC significantly shortened the apparent recovery time of mobility in rats. PPC treatment significantly promoted the formation of cartilage callus, endochondral ossification, and angiogenesis at the fracture site. In vitro, PPC promoted the proliferative viability of HUVECs, their ability to heal wounds, and their ability to penetrate membranes in the Transwell apparatus and increased the tube formation of cells. The transcription of VEGFA, VEGFR2, PLCγ, RAS, ERK1/2 and MEK1/2 was significantly up regulated by PPC. Further, the protein level results demonstrated a significant increase in the expression of VEGFA, VEGFR2, MEK1/2, and ERK1/2 proteins. In conclusion, our findings suggest that PPC promotes angiogenesis by activating the VEGFA/VEGFR2 and downstream signaling pathway, thereby accelerating fracture healing.

S6K1 deficiency in tumor stroma impairs lung metastasis of melanoma in mice.

Accumulating data suggest that ribosomal protein S6 kinase 1 (S6K1), an effector in the mammalian target of rapamycin (mTOR) pathway, plays pleiotropic roles in tumor progression. However, to date, while the tumorigenic function of S6K1 in tumor cells has been well elucidated, its role in the tumor stroma remains poorly understood. We recently showed that S6K1 mediates vascular endothelial growth factor A (VEGF-A) production in macrophages, thereby supporting tumor angiogenesis and growth. As macrophage-derived VEGF-A is crucial for both tumor cell intravasation and extravasation across the vascular endothelium, our previous findings suggest that stromal S6K1 signaling is required for tumor metastatic spread. Therefore, we aimed to determine the impact of host S6K1 depletion on tumor metastasis using a murine model of pulmonary metastasis (S6k1-/- mice implanted with B16F10 melanoma). The ablation of S6K1 in the host microenvironment significantly reduced the metastasized B16F10 melanoma cells on the lung surface in both spontaneous and intravenous lung metastasis mouse models without affecting the incidence of metastasis to distant lymph nodes. In addition, stromal S6K1 loss decreased the number of tumor cells circulating in the peripheral blood of mice bearing B16F10 xenografts without affecting the vascular leakage induced by VEGF-A in vivo. These observations demonstrate that S6K1 signaling in host cells other than endothelial cells is required to modulate the host microenvironment to facilitate the metastatic spread of tumors via blood circulation, thus revealing its novel role in the tumor stroma during tumor progression.

Tibial transverse transport induces mobilization of endothelial progenitor cells to accelerate angiogenesis and ulcer wound healing through the VEGFA/CXCL12 pathway.

BACKGROUND: Tibial transverse transport (TTT) can promote the healing of chronic foot ulcers, but the specific cellular and molecular mechanisms by which TTT promotes wound healing remain unclear. METHODS: New Zealand White rabbits were selected to induce foot ulcer models. The treatment included unilateral TTT surgery and bilateral TTT surgery. Observation of tissue neovascularization structure by HE staining and CD31 immunofluorescence detection. Collagen fiber formation was detected through the Masson staining. The mobilization of endothelial progenitor cell (EPCs) were analyzed by VEGFR2 immunofluorescence detection and flow cytometry detection of the number of VEGFR2/Tie-2-positive cells in peripheral blood. ELISA and qPCR assay were performed to detect VEGFA and CXCL12 levels. RESULTS: The complete healing time of ulcer surfaces in sham, unilateral and bilateral TTT groups was about 22 days, 17 days and 13 days, respectively. TTT treatment significantly increased the deposition of granulation tissue and epithelialization of wounds. It also led to an increase in collagen fiber content and the level of the microvascular marker CD31. Furthermore, TTT treatment upregulated the levels of VEGFA and CXCL12 in peripheral blood and wound tissues, as well as increased the expression of VEGFR2 in wound tissues and the proportion of VEGFR2/Tie-2 in peripheral blood. Moreover, these effects of TTT treatment in the bilateral group was more significant than that in the unilateral group. CONCLUSIONS: TTT may facilitate wound fibroblasts to release VEGFA and CXCL12, causing EPC mobilization, thus promoting angiogenesis and ulcer wound healing.

m6A modification of VEGFA mRNA by RBM15/YTHDF2/IGF2BP3 contributes to angiogenesis of hepatocellular carcinoma.

Vascular endothelial growth factor A (VEGFA) plays a critical role as a potent angiogenesis factor and is highly expressed in hepatocellular carcinoma (HCC). Although the expression of VEGFA has been strongly linked to the aggressive nature of HCC, the specific posttranscriptional modifications that might contribute to VEGFA expression and HCC angiogenesis are not yet well understood. In this study, we aimed to investigate the epitranscriptome regulation of VEGFA in HCC. A comprehensive analysis integrating MeRIP-seq, RNA-seq, and crosslinking-immunprecipitation-seq data revealed that VEGFA was hypermethylated in HCC and identified the potential m6A regulators of VEGFA including a m6A methyltransferase complex component RBM15 and the two readers, YTHDF2 and IGF2BP3. Through rigorous cell and molecular biology experiments, RBM15 was validated as a key component of methyltransferase complex responsible for m6A methylation of VEGFA, which was subsequently recognized and stabilized by IGF2BP3 and YTHDF2, leading to enhanced VEGFA expression and VEGFA-related functions such as human umbilical vascular endothelial cells (HUVEC) migration and tube formation. In the HCC xenograft model, knockdown of RBM15, IGF2BP3, or YTHDF2 resulted in reduced expression of VEGFA, accompanied by significant inhibition of tumor growth closely associated with VEGFA expression and angiogenesis. Furthermore, our analysis of HCC clinical samples identified positive correlations between the expression levels of VEGFA and the regulators RBM15, IGF2BP3, and YTHDF2. Collectively, these findings offer novel insights into the posttranscriptional modulation of VEGFA and provide potential avenues for alternative approaches to antiangiogenesis therapy targeting VEGFA.

Serum VEGF-A levels on admission in COVID-19 patients correlate with SP-D and neutrophils, reflecting disease severity: A prospective study.

BACKGROUND AND OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in significant global morbidity and mortality. This study aimed to investigate the clinical significance of serum vascular endothelial growth factor A (VEGF-A) in COVID-19 patients and its association with disease severity and pulmonary injury. METHODS: We prospectively collected data from 71 hospitalized COVID-19 patients between June 2020 and January 2021. Patients were classified as either mild or severe based on their oxygen requirements during hospitalization. Serum VEGF-A levels were measured using an ELISA kit. RESULTS: In comparison to mild cases, significantly elevated serum VEGF-A levels were observed in severe COVID-19 patients. Furthermore, VEGF-A levels exhibited a positive correlation with white blood cell count, neutrophil count, and lymphocyte count. Notably, serum surfactant protein-D (SP-D), an indicator of alveolar epithelial cell damage, was significantly higher in patients with elevated VEGF-A levels. CONCLUSION: These results suggest that elevated serum VEGF-A levels could serve as a prognostic biomarker for COVID-19 as it is indicative of alveolar epithelial cell injury caused by SARS-CoV-2 infection. Additionally, we observed a correlation between VEGF-A and neutrophil activation, which plays a role in the immune response during endothelial cell injury, indicating a potential involvement of angiogenesis in disease progression. Further research is needed to elucidate the underlying mechanisms of VEGF-A elevation in COVID-19.

Tanshinone IIA attenuates osteoarthritis via inhibiting aberrant angiogenesis in subchondral bone.

Excessive angiogenesis in subchondral bone is a pathological feature of osteoarthritis (OA). Tanshinone IIA (TIIA), an active compound found in Salvia miltiorrhiza, demonstrates significant anti-angiogenic properties. However, the effect of TIIA on abnormal subchondral angiogenesis in OA is still unclear. This study aims to investigate the mechanism of TIIA in modulating subchondral bone angiogenesis during OA and assess its therapeutic potential in OA. Our findings demonstrate that TIIA attenuated articular cartilage degeneration, normalized subchondral bone remodeling, and effectively suppressed aberrant angiogenesis within subchondral bone in monosodium iodoacetate (MIA)-induced OA mice. Additionally, the angiogenesis capacity of primary CD31hiEmcnhi endothelial cells was observed to be significantly reduced after treatment with TIIA in vitro. Mechanically, TIIA diminished the proportion of hypertrophic chondrocytes, ultimately leading to a substantial reduction in the secretion of vascular endothelial growth factor A (VEGFA). The supernatant of hypertrophic chondrocytes promoted the tube formation of CD31hiEMCNhi endothelial cells, whereas TIIA inhibited this process. Furthermore, TIIA effectively suppressed the expression of vascular endothelial growth factor receptor 2 (VEGFR2) along with its downstream MAPK pathway in CD31hiEmcnhi endothelial cells. In conclusion, our data indicated that TIIA could effectively inhibit the abnormal angiogenesis in subchondral bone during the progression of OA by suppressing the VEGFA/VEFGR2/MAPK pathway. These findings significantly contribute to our understanding of the abnormal angiogenesis in OA and offer a promising therapeutic target for OA treatment.

Umbilical cord mesenchymal stem cells from gestational diabetes show impaired ability to up-regulate paracellular permeability from sub-endothelial niche.

In vitro studies have shown that Wharton's jelly mesenchymal stem cells (WJ-MSCs) can cross umbilical and uterine endothelial barriers and up-regulate endothelial junctional integrity from sub-endothelial niches. This pericytic behaviour may be lost in pregnancies complicated by gestational diabetes (GDM), where increased vascular permeability and junctional disruption are reported. The aim of the present study was to investigate whether WJ-MSCs isolated from GDM pregnancies displayed any changes in morphology, proliferation, VEGF-A secretion, and their ability to influence paracellular junctional composition and permeability. WJ-MSCs were isolated from human umbilical cords from normal pregnancies (nWJ-MSCs, n=13) and those complicated by GDM (gWJ-MSCs), either diet-controlled (d-GDM, n=13) or metformin-treated (m-GDM, n=9). We recorded that 4-fold more WJ-MSCs migrated from m-GDM, and 2.5-fold from d-GDM cord samples compared with the normal pregnancy. gWJ-MSCs showed a less predominance of spindle-shaped morphology and secreted 3.8-fold more VEGF-A compared with nWJ-MSCs. The number of cells expressing CD105 (Endoglin) was higher in gWJ-MSCs compared with nWJ-MSCs (17%) at P-2. The tracer leakage after 24 h across the HUVEC + gWJ-MSCs bilayer was 22.13% and 11.2% higher in the m-GDM and d-GDM, respectively, HUVEC + nWJ-MSCs. Transfection studies with siRNAs that target Endoglin were performed in n-WJ-MSCs; transfected cells were co-cultured with HUVEC followed by permeability studies and VE-cadherin analyses. Loss of Endoglin also led to increased VEGF-A secretion, increased permeability and affected endothelial stabilization. These results reinforce the pericytic role of nWJ-MSCs to promote vascular repair and the deficient ability of gWJ-MSCs to maintain endothelial barrier integrity.

WTAP activates MAPK signaling through m6A methylation in VEGFA mRNA-mediated by YTHDC1 to promote colorectal cancer development.

N6-methyladenosine modification, especially Wilms tumor 1-associated protein (WTAP), is reportedly associated with a variety of cancers, including colorectal cancer (CRC). Angiogenesis also plays an important role in the occurrence and development of CRC. However, only a few studies have reported the biological mechanisms underlying this connection. Therefore, tissue microarray and public database were used to explore WTAP levels in CRC. Then, WTAP was down-regulated and over-expressed, respectively. CCK8, EdU, colony formation, and transwell experiments were performed to study the role of WTAP in CRC. Combined RNA sequencing and m6A RNA immunoprecipitation (MeRIP) sequencing, we found downstream molecules VEGFA. Moreover, a tube formation assay was executed for tumor angiogenesis. Finally, a subcutaneous tumorigenesis assay in nude mice was used to examine the tumor-promoting effect of WTAP in vivo. In the present study, WTAP was significantly upregulated in CRC cells and patients with CRC. Moreover, higher WTAP expression was observed in the TCGA and CPATC databases in CRC tissues. WTAP over-expression exacerbates cell proliferation, migration, invasion, and angiogenesis. Conversely, WTAP knockdown inhibited the malignant biological behavior of CRC cells. Mechanistically, WTAP positively regulated VEGFA, as identified using RNA sequencing and MeRIP sequencing. Moreover, we identified YTHDC1 as a downstream effector of the YTHDC1-VEGFA axis in CRC. Furthermore, increased WTAP expression activated the MAPK signaling pathway, which led to enhanced angiogenesis. In conclusion, our study revealed that the WTAP/YTHDC1/VEGFA axis promotes CRC development, especially angiogenesis, suggesting that it may act as a potential biomarker of CRC.

Transcriptomic signatures of individual cell types in cerebral cavernous malformation.

Cerebral cavernous malformation (CCM) is a hemorrhagic neurovascular disease with no currently available therapeutics. Prior evidence suggests that different cell types may play a role in CCM pathogenesis. The contribution of each cell type to the dysfunctional cellular crosstalk remains unclear. Herein, RNA-seq was performed on fluorescence-activated cell sorted endothelial cells (ECs), pericytes, and neuroglia from CCM lesions and non-lesional brain tissue controls. Differentially Expressed Gene (DEG), pathway and Ligand-Receptor (LR) analyses were performed to characterize the dysfunctional genes of respective cell types within CCMs. Common DEGs among all three cell types were related to inflammation and endothelial-to-mesenchymal transition (EndMT). DEG and pathway analyses supported a role of lesional ECs in dysregulated angiogenesis and increased permeability. VEGFA was particularly upregulated in pericytes. Further pathway and LR analyses identified vascular endothelial growth factor A/ vascular endothelial growth factor receptor 2 signaling in lesional ECs and pericytes that would result in increased angiogenesis. Moreover, lesional pericytes and neuroglia predominantly showed DEGs and pathways mediating the immune response. Further analyses of cell specific gene alterations in CCM endorsed potential contribution to EndMT, coagulation, and a hypoxic microenvironment. Taken together, these findings motivate mechanistic hypotheses regarding non-endothelial contributions to lesion pathobiology and may lead to novel therapeutic targets. Video Abstract.