Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, Tennessee.
Department of Biochemistry, Vanderbilt University, Nashville, Tennessee.
Am J Physiol Renal Physiol. 2020 Mar 1;318(3):F647-F659. doi: 10.1152/ajprenal.00288.2019. Epub 2020 Jan 27.
CD148 is a transmembrane protein tyrosine phosphatase (PTP) that is expressed in the renal vasculature, including the glomerulus. Previous studies have shown that CD148 plays a role in the negative regulation of growth factor signals (including epidermal growth factor and vascular endothelial growth factor), suppressing cell proliferation and transformation. However, the role of CD148 in kidney disease remains unknown. Here, we generated an agonistic anti-CD148 antibody and evaluated its effects in murine diabetic nephropathy (DN). Monoclonal antibodies (mAbs) against the mouse CD148 ectodomain sequence were generated by immunizing CD148 knockout (CD148KO) mice. The mAbs that increased CD148 activity were selected by biological (proliferation) and biochemical (PTP activity) assays. The mAb (18E1) that showed strong agonistic activity was injected (10 mg/kg ip) in streptozotocin-induced wild-type and CD148KO diabetic mice for 6 wk, and the renal phenotype was then assessed. The effects of 18E1 mAb in podocyte growth factor signals were also assessed in culture. Compared with control IgG, 18E1 mAb significantly decreased albuminuria and mesangial expansion without altering hyperglycemia and blood pressure in wild-type diabetic mice. Immunohistochemical evaluation showed that 18E1 mAb significantly prevented the reduction of podocyte number and nephrin expression and decreased glomerular fibronectin expression and renal macrophage infiltration. The 18E1 mAb showed no effects in CD148KO diabetic mice. Furthermore, we demonstrated that 18E1 mAb reduces podocyte epidermal growth factor receptor signals in culture and in diabetic mice. These findings suggest that agonistic anti-CD148 mAb attenuates DN in mice, in part by reducing epidermal growth factor receptor signals in podocytes. This antibody may be used for the treatment of early DN.
CD148 是一种跨膜蛋白酪氨酸磷酸酶（PTP），在包括肾小球在内的肾脏脉管系统中表达。先前的研究表明，CD148 在生长因子信号（包括表皮生长因子和血管内皮生长因子）的负调控中发挥作用，抑制细胞增殖和转化。然而，CD148 在肾脏疾病中的作用尚不清楚。在这里，我们生成了一种激动型抗 CD148 抗体，并在小鼠糖尿病肾病（DN）中评估了其效果。通过免疫 CD148 敲除（CD148KO）小鼠产生了针对小鼠 CD148 外显子序列的单克隆抗体（mAbs）。通过生物（增殖）和生化（PTP 活性）测定选择增加 CD148 活性的 mAbs。显示出强激动活性的 mAb（18E1）以 10 mg/kg ip 注射到链脲佐菌素诱导的野生型和 CD148KO 糖尿病小鼠中 6 周，然后评估肾脏表型。还在培养物中评估了 18E1 mAb 在足细胞生长因子信号中的作用。与对照 IgG 相比，18E1 mAb 可显著降低白蛋白尿和系膜扩张，而不改变野生型糖尿病小鼠的高血糖和血压。免疫组织化学评估显示，18E1 mAb 可显著防止足细胞数量和 Nephrin 表达减少，并减少肾小球纤维连接蛋白表达和肾脏巨噬细胞浸润。18E1 mAb 在 CD148KO 糖尿病小鼠中没有作用。此外，我们证明 18E1 mAb 在培养物和糖尿病小鼠中减少足细胞表皮生长因子受体信号。这些发现表明，激动型抗 CD148 mAb 可部分通过减少足细胞中的表皮生长因子受体信号来减轻小鼠的 DN。该抗体可用于早期 DN 的治疗。
