Ocular neovascularization is a comprehensive process involved in retinal vascular development and several blinding diseases such as age-related macular degeneration and retinopathy of prematurity, with vascular endothelial growth factor (VEGF) regarded as the master regulator. However, the qualified effect of anti-VEGF therapy reveals that the underlying mechanisms are still not clearly identified. To initialize angiogenesis, endothelial cells undergo a phenotype switching to generate highly migratory and invasive cells. This process shares certain similar characters observed in endothelial-mesenchymal transition (EndMT). Here, we found that SNAI1, an EndMT transcription factor, was expressed by endothelial cells in both physiological and pathological ocular neovascularization. SNAI1 overexpression triggered cell morphological change and enhanced cell motility, while loss of SNAI1 attenuated migration, invasion and sprouting. RNA sequence analysis further revealed that SNAI1 knockdown decreased the expression of genes related to cytoskeleton rearrangement and ECM remodeling. Moreover, intravitreal injection of small interfering RNA of SNAI1 suppressed new vessel formation in developing retina as well as mice model of choroidal neovascularization and oxygen-induced retinopathy. Therefore, we propose that the EndMT transcription factor SNAI1 promotes the early phase of ocular neovascularization and may provide a potential therapeutic target.

To investigate the role of macrophages in oxygen-induced retinal neovascularization (NV) in mice, particularly the involvement of bone marrow-derived cells (BMCs) and the underlying mechanisms, BMCs from green fluorescent protein (GFP) transgenic mice were transplanted into postnatal day (P) 1 mice after irradiation. The mice were exposed to 75 % oxygen from P7 to P12 to initiate oxygen-induced retinopathy (OIR). The macrophages were depleted by injection of clodronate-liposomes (lip) intraperitoneally. The eyes were collected at P12 and P17. Retinal flatmounts and histopathological cross-sections were performed to analyze the severity of retinal NV and BMC recruitment. BMCs immunopositive for CD31 (PECAM-1; endothelial cell marker) and α-SMA (smooth muscle cell marker) antigens were detected using a confocal microscope. Expression of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) mRNA was detected by RT-PCR. The VEGF, SDF-1, CXCR4 and CD45 protein expression was detected by western blot examination. The retinal avascular area in OIR mice at P12 was unaffected after macrophage depletion carried out twice (38.27 ± 1.92 % reduction) using clodronate-lip. The retinal avascular area and the NV area at P17 were reduced after macrophage depletion four times (79.53 ± 1.02 % reduction); these findings were supported by retinal flatmounts and histopathological cross-sections. Macrophage depletion led to significant inhibition of BMC recruitment into the NV tufts at P17, with decreased expression of retinal VEGF, SDF-1, CXCR4 and CD45. The recruited BMCs differentiated primarily into CD31-positive endothelial cells (ECs) and α-SMA-positive smooth muscle cells (SMCs). This study suggested that macrophages promoted the vasculogenesis of retinal NV, particularly the contribution of BMCs in the mouse OIR model, which might be triggered by VEGF and SDF-1 production.

Background Intrahepatic cholangiocarcinoma (iCCA) is a highly lethal malignancy of the biliary tract. Analysis of somatic mutational profiling can reveal new prognostic markers and actionable treatment targets. In this study, we explored the utility of genomic mutation signature and tumor mutation burden (TMB) in predicting prognosis in iCCA patients. Methods Whole-exome sequencing and corresponding clinical data were collected from the ICGC portal and cBioPortal database to detect the prognostic mutated genes and determine TMB values. To identify the hub prognostic mutant signature, we used Cox regression and Lasso feature selection. Mutation-related signature (MRS) was constructed using multivariate Cox regression. The predictive performances of MRS and TMB were assessed using Kaplan–Meier (KM) analysis and receiver operating characteristic (ROC). We performed a functional enrichment pathway analysis using gene set enrichment analysis (GSEA) for mutated genes. Based on the MRS, TMB, and the TNM stage, a nomogram was constructed to visualize prognosis in iCCA patients. Results The mutation landscape illustrated distributions of mutation frequencies and types in iCCA, and generated a list of most frequently mutated genes (such as Tp53, KRAS, ARID1A, and IDH1). Thirty-two mutated genes associated with overall survival (OS) were identified in iCCA patients. We obtained a six-gene signature using the Lasso and Cox method. AUCs for the MRS in the prediction of 1-, 3-, and 5-year OS were 0.759, 0.732, and 0.728, respectively. Kaplan–Meier analysis showed a significant difference in prognosis for patients with iCCA having a high and low MRS score (P < 0.001). GSEA was used to show that several signaling pathways, including MAPK, PI3K-AKT, and proteoglycan, were involved in cancer. Conversely, survival analysis indicated that TMB was significantly associated with prognosis. GSEA indicated that samples with high MRS or TMB also showed an upregulated expression of pathways involved in tumor signaling and the immune response. Finally, the predictive nomogram (that included MRS, TMB, and the TNM stage) demonstrated satisfactory performance in predicting survival in patients with iCCA. Conclusions Mutation-related signature and TMB were associated with prognosis in patients with iCCA. Our study provides a valuable prognostic predictor for determining outcomes in patients with iCCA.