Zimering M B, Grinberg M, Burton J, Pang Kch
Medical Service, Veterans Affairs New Jersey Healthcare System, East Orange, New Jersey, USA.
Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ.
Endocrinol Diabetes Metab J. 2020 Aug;4(3). Epub 2020 Aug 28.
Circulating neurotoxic autoantibodies to the 5-hydroxytryptamine 2A receptor were increased in older adult type 2 diabetes in association with certain neurodegenerative complications. The male Zucker diabetic fatty (ZDF) rat is a model system for studies of obese, type 2 diabetes mellitus. The aim of the current study was to test for (and compare) circulating neurotoxic autoantibodies to the 5-hydroxytryptamine 2A receptor in the Zucker diabetic fatty rat and age-matched lean Zucker rat strains.
Plasma from lean and Zucker diabetic fatty rat (obtained at different developmental stages) was subjected to protein G affinity chromatography. The resulting immunoglobulin G fraction was tested for neurotoxicity (acute neurite retraction, accelerated neuron loss) in N2A mouse neuroblastoma cells and for binding to a linear synthetic peptide corresponding to the second extracellular loop of the 5-hydroxytryptamine 2A receptor.
The male Zucker diabetic fatty rat () and two Zucker lean strains (+/?) and (/+) harbored autoantibodies to the 5-hydroxytryptamine 2A receptor which appeared spontaneously around 7-8.5 weeks of age. The circulating autoantibodies persisted until at least 25 weeks of age in the Zucker diabetic fatty rat and in the Zucker heterozygote (/+), but were no longer detectable in 25-week-old lean (+/?) Zucker rats. Autoantibody-induced acute neurite retraction and accelerated loss in mouse neuroblastoma N2A cells was dose-dependently prevented by selective antagonists of the 5-hydroxytryptamine 2A receptor. It was also substantially prevented by co-incubation with antagonists of RhoA/Rho kinase-mediated signaling (Y27632) or Gq11/phospholipase C/inositol triphosphate receptor-coupled signaling.
These data suggest that neurotoxic 5-hydroxytryptamine 2A receptor-targeting autoantibodies increase in the aging male Zucker diabetic fatty rat and in male Zucker lean rats harboring a heterozygous mutation, but not in age-matched, older Zucker lean rats lacking a known leptin receptor mutation. The Zucker genetic strain may be useful in studies of the role of humoral and/or innate immunity in late neurodegeneration.
在老年2型糖尿病患者中，针对5-羟色胺2A受体的循环神经毒性自身抗体增加，且与某些神经退行性并发症相关。雄性Zucker糖尿病肥胖（ZDF）大鼠是用于研究肥胖型2型糖尿病的模型系统。本研究的目的是检测（并比较）Zucker糖尿病肥胖大鼠和年龄匹配的瘦型Zucker大鼠品系中针对5-羟色胺2A受体的循环神经毒性自身抗体。
对来自瘦型和Zucker糖尿病肥胖大鼠（在不同发育阶段获取）的血浆进行蛋白G亲和层析。对所得的免疫球蛋白G组分进行检测，观察其对N2A小鼠神经母细胞瘤细胞的神经毒性（急性神经突回缩、加速神经元丢失）以及与对应于5-羟色胺2A受体第二细胞外环的线性合成肽的结合情况。
雄性Zucker糖尿病肥胖大鼠（）以及两个Zucker瘦型品系（+/?）和（/+）体内存在针对5-羟色胺2A受体的自身抗体，这些抗体在7 - 8.5周龄左右自发出现。在Zucker糖尿病肥胖大鼠和Zucker杂合子（/+）中，循环自身抗体至少持续到25周龄，但在25周龄的瘦型（+/?）Zucker大鼠中不再能检测到。5-羟色胺2A受体的选择性拮抗剂可剂量依赖性地阻止自身抗体诱导的小鼠神经母细胞瘤N2A细胞急性神经突回缩和加速丢失。与RhoA/Rho激酶介导的信号传导拮抗剂（Y27632）或Gq11/磷脂酶C/肌醇三磷酸受体偶联信号传导拮抗剂共同孵育也可显著阻止这种情况。
这些数据表明，在衰老的雄性Zucker糖尿病肥胖大鼠以及携带杂合突变的雄性Zucker瘦型大鼠中，针对神经毒性5-羟色胺2A受体的自身抗体增加，但在年龄匹配、无已知瘦素受体突变的老年Zucker瘦型大鼠中未增加。Zucker遗传品系可能有助于研究体液和/或固有免疫在晚期神经退行性变中的作用。
