BGN stimulates retinal pathological angiogenesis via up-regulation of CXCL12 expression in pericytes (human)

Retinal pathological angiogenesis (PA) is a common hallmark in proliferative retinopathies, including age-related macular degeneration (AMD), proliferative diabetic retinopathy (PDR), and retinopathy of prematurity (ROP). The mechanisms underlying PA is complex and incompletely understood. Using oxygen-induced retinopathy (OIR) mouse as a model, the role of extracellular matrix (ECM) protein biglycan (BGN) in PA was studied. Significant upregulation of BGN in the retina of OIR mice and in neovascular proliferative membranes of PDR patients was found. The reduction of BGN expression by Bgn-specific small interfering RNA (siRNA) effectively diminished retinal PA in OIR mouse. Subsequent analysis of the mouse OIR retinal single-cell RNA sequencing data from the Gene Expression Omnibus dataset (GSE150703) suggested pericyte as a source of BGN. This was verified using cultured retinal capillary pericytes. BGN expression in pericytes was highly sensitive to hypoxic stimulation. BGN stimulated retinal PA via the upregulation of C-X-C motif chemokine ligand 12 (CXCL12). Inhibition of the CXCL12-CXCR4 axis effectively diminished PA in OIR mouse. In conclusion, this study demonstrated the stimulatory role of BGN in retinal PA, identified the link between BGN and CXCL12 expression, and further highlighted the role of pericytes in retinal PA. To investigate the role of pericyte-derived BGN in the retinal PA, the gene expression changes of HRMVPCs treated with BGN-specific siRNA or control siRNA under hypoxic conditions for 24 hours was compared.

视网膜病理性血管生成（Retinal pathological angiogenesis，PA）是增生性视网膜病变的常见标志性特征，涵盖年龄相关性黄斑变性（age-related macular degeneration，AMD）、增生性糖尿病视网膜病变（proliferative diabetic retinopathy，PDR）及早产儿视网膜病变（retinopathy of prematurity，ROP）。该病理过程的发病机制复杂，目前尚未完全阐明。本研究以氧诱导视网膜病变（oxygen-induced retinopathy，OIR）小鼠为模型，探究了细胞外基质（extracellular matrix，ECM）蛋白饰胶蛋白聚糖（biglycan，BGN）在病理性血管生成中的作用。研究发现，OIR小鼠的视网膜组织以及PDR患者的新生血管增生膜中，BGN的表达均显著上调。通过BGN特异性小干扰RNA（small interfering RNA，siRNA）降低BGN的表达，可有效抑制OIR小鼠的视网膜病理性血管生成。随后，对取自基因表达综合数据库（Gene Expression Omnibus，GEO）数据集GSE150703的OIR小鼠视网膜单细胞RNA测序数据进行分析，结果提示周细胞为BGN的来源之一，该结论通过培养的视网膜毛细血管周细胞实验得以验证。周细胞内的BGN表达对缺氧刺激呈现高度敏感性。BGN可通过上调C-X-C基序趋化因子配体12（C-X-C motif chemokine ligand 12，CXCL12）的表达，促进视网膜病理性血管生成。抑制CXCL12-CXCR4轴可有效减轻OIR小鼠的视网膜病理性血管生成。综上，本研究证实了BGN在视网膜病理性血管生成中的促进作用，明确了BGN与CXCL12表达之间的关联，并进一步凸显了周细胞在视网膜病理性血管生成中的功能。为探究周细胞来源的BGN在视网膜病理性血管生成中的作用，本研究比较了缺氧条件下经BGN特异性siRNA或对照siRNA处理24小时的HRMVPCs的基因表达变化。