Proteomic profiling in mouse kidneys post-UUO

Increased export of transglutaminase-2 (TG2) by tubular epithelial cells (TECs) into the surrounding interstitium modifies the extracellular homeostatic balance leading to fibrotic membrane expansion. Although silencing of extracellular TG2 ameliorates progressive kidney scarring in animal models of chronic kidney disease, the pathway through which TG2 is secreted from TECs and contributes to disease progression has not been elucidated. In this study, we developed a global proteomic approach to identify binding partners of TG2 responsible for TG2 externalization in kidneys subjected to unilateral ureteric obstruction, using TG2-knockout kidneys as negative controls. We report a robust and unbiased analysis of the membrane interactome of TG2 in fibrotic kidneys relative to the entire proteome post-UUO detected by SWATH-mass spectrometry.

肾小管上皮细胞（tubular epithelial cells，TECs）向周围间质分泌的谷氨酰胺转移酶2（transglutaminase-2，TG2）增多，会打破细胞外稳态平衡，进而引发纤维化膜扩张。尽管在慢性肾脏病（chronic kidney disease）动物模型中，沉默细胞外TG2可缓解进行性肾瘢痕化，但肾小管上皮细胞分泌TG2并促进疾病进展的具体通路仍未阐明。本研究开发了一种全局蛋白质组学方法，以TG2基因敲除肾脏作为阴性对照，在单侧输尿管梗阻（unilateral ureteric obstruction，UUO）模型的肾脏中鉴定介导TG2外泌的TG2结合伴侣。本研究通过SWATH质谱（SWATH-mass spectrometry）检测，相较于单侧输尿管梗阻术后的全蛋白质组，对纤维化肾脏中TG2的膜相互作用组进行了可靠且无偏倚的分析。