LPCAT4 Knockdown Alters Barrier Integrity and Cellular Bioenergetics in Human Urothelium

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...

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Bibliographic Details
Published in:	International journal of molecular sciences 2022-10, Vol.23 (19), p.11871
Main Authors:	Mason, Andrew S., Varley, Claire L., Foody, Olivia M., Li, Xiang, Skinner, Katie, Walker, Dawn, Larson, Tony R., Wakamatsu, Daisuke, Baker, Simon C., Southgate, Jennifer
Format:	Article
Language:	eng
Subjects:	Bioenergetics Differentiation Diglycerides Epithelium Flow velocity Glycerol glycerophospholipids Homeostasis Kinases lipidomics Lipids Membrane proteins Membranes Motility Peroxisome proliferator-activated receptors Phenotypes Phosphate esters phosphatidylcholine Proteins Restitution Structural integrity Transcriptomics transepithelial electrical resistance Urinary tract Urine Urothelium Wounding
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Summary:	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 LPCAT4. LPCAT4 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 LPCAT4 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.
ISSN:	1422-0067 1661-6596 1422-0067