Jack Birch Unit for Molecular Carcinogenesis, Department of Biology and York Biomedical Research Institute, University of York, Heslington, York YO10 5DD, UK.
Department of Computer Science, University of Sheffield, Regent Court, 211 Portobello, Sheffield S1 4DP, UK.
Int J Mol Sci. 2022 Oct 6;23(19):11871. doi: 10.3390/ijms231911871.
Urothelium is a transitional, stratified epithelium that lines the lower urinary tract, providing a tight barrier to urine whilst retaining the capacity to stretch and rapidly resolve damage. The role of glycerophospholipids in urothelial barrier function is largely unknown, despite their importance in membrane structural integrity, protein complex assembly, and the master regulatory role of PPARγ in urothelial differentiation. We performed lipidomic and transcriptomic characterisation of urothelial differentiation, revealing a metabolic switch signature from fatty acid synthesis to lipid remodelling, including 5-fold upregulation of . knockdown urothelial cultures exhibited an impaired proliferation rate but developed elevated trans-epithelial electrical resistances upon differentiation, associated with a reduced and delayed capacity to restitute barrier function after wounding. Specific reduction in 18:1 PC fatty acyl chains upon knockdown was consistent with LPCAT4 specificity, but was unlikely to elicit broad barrier function changes. However, transcriptomic analysis of knockdown supported an LPC-induced reduction in DAG availability, predicted to limit PKC activity, and TSPO abundance, predicted to limit endogenous ATP. These phenotypes were confirmed by PKC and TSPO inhibition. Together, these data suggest an integral role for lipid mediators in urothelial barrier function and highlight the strength of combined lipidomic and transcriptomic analyses for characterising tissue homeostasis.
尿路上皮是一种过渡性的、复层上皮细胞，位于下尿路，为尿液提供紧密的屏障，同时保持伸展和迅速解决损伤的能力。尽管甘油磷脂在膜结构完整性、蛋白质复合物组装以及 PPARγ 在尿路上皮分化中的主要调节作用中非常重要，但它们在尿路上皮屏障功能中的作用在很大程度上尚不清楚。我们对尿路上皮分化进行了脂质组学和转录组学特征分析，揭示了从脂肪酸合成到脂质重塑的代谢转换特征，包括. 敲低尿路上皮培养物表现出增殖率受损，但在分化时会发展出更高的跨上皮电阻，与损伤后恢复屏障功能的能力降低和延迟相关。敲低后 18:1 PC 脂肪酸链的特异性减少与 LPCAT4 的特异性一致，但不太可能引起广泛的屏障功能变化。然而，. 敲低的转录组分析支持 LPC 诱导的 DAG 可用性降低，预测会限制 PKC 活性，以及 TSPO 丰度，预测会限制内源性 ATP。这些表型通过 PKC 和 TSPO 抑制得到证实。综上所述，这些数据表明脂质介体在尿路上皮屏障功能中具有重要作用，并强调了脂质组学和转录组学联合分析在表征组织稳态方面的优势。
