During ageing, the glomerular and tubular basement membranes (BM) of the kidney undergo a progressive decline in function that is underpinned by histological changes, including glomerulosclerosis and tubular interstitial fibrosis and atrophy. This BM-specific ageing is thought to result from damage accumulation to long-lived extracellular matrix (ECM) protein structures. Determining which BM proteins are susceptible to these structure-associated changes, and the possible mechanisms and downstream consequences, is critical to understand age-related kidney degeneration and to identify markers for therapeutic intervention. Peptide location fingerprinting (PLF) is an emerging proteomic mass spectrometry analysis technique capable of identifying ECM proteins with structure-associated differences that may occur by damage modifications in ageing. Here, we apply PLF as a bioinformatic screening tool to identify BM proteins with structure-associated differences between young and aged human glomerular and tubulointerstitial compartments. Several functional regions within key BM components displayed alterations in tryptic peptide yield, reflecting potential age-dependent shifts in molecular (e.g. laminin-binding regions in agrin) and cellular (e.g. integrin-binding regions in laminins 521 and 511) interactions, oxidation (e.g. collagen IV) and the fragmentation and release of matrikines (e.g. canstatin and endostatin from collagens IV and XVIII). Furthermore, we found that periostin and the collagen IV α2 chain exhibited structure-associated differences in ageing that were conserved between human kidney and previously analysed mouse lung, revealing BM components that harbour shared susceptibilities across species and organs.

在衰老过程中，肾脏的肾小球和肾小管基底膜（BM）的功能逐渐下降，其基础是组织学变化，包括肾小球硬化和肾小管间质纤维化和萎缩。这种 BM 特异性衰老被认为是由于长寿命细胞外基质 (ECM) 蛋白质结构的损伤积累造成的。确定哪些 BM 蛋白容易受到这些结构相关变化的影响，以及可能的机制和下游后果，对于了解与年龄相关的肾变性和识别治疗干预的标志物至关重要。肽位置指纹识别 (PLF) 是一种新兴的蛋白质组质谱分析技术，能够识别具有结构相关差异的 ECM 蛋白，这些差异可能因衰老过程中的损伤修饰而发生。在这里，我们应用 PLF 作为生物信息学筛选工具来识别年轻人和老年人肾小球和肾小管间质室之间具有结构相关差异的 BM 蛋白。关键 BM 成分内的几个功能区域显示胰蛋白酶肽产量的变化，反映了分子（例如集聚蛋白中的层粘连蛋白结合区域）和细胞（例如层粘连蛋白 521 和 511 中的整联蛋白结合区域）相互作用、氧化（例如IV 型胶原蛋白）以及基质蛋白（例如 IV 型胶原蛋白和 XVIII 型胶原蛋白中的坎抑素和内皮抑素）的碎裂和释放。此外，我们发现骨膜素和 IV 型胶原 α2 链在衰老过程中表现出与结构相关的差异，这些差异在人类肾脏和之前分析的小鼠肺之间是保守的，揭示了跨物种和器官具有共同易感性的 BM 成分。