Glomerular hyperfiltration is an important mechanism in the development of albuminuria. During hyperfiltration, podocytes are exposed to increased fluid flow shear stress (FFSS) in Bowman's space. Elevated Prostaglandin E2 (PGE2) synthesis and upregulated cyclooxygenase 2 (Cox2) are associated with podocyte injury by FFSS. We aimed to elucidate a PGE2 autocrine/paracrine pathway in human podocytes (hPC). We developed a modified liquid chromatography tandem mass spectrometry (LC/ESI-MS/MS) protocol to quantify cellular PGE2, 15-keto-PGE2, and 13,14-dihydro-15-keto-PGE2 levels. hPC were treated with PGE2 with or without separate or combined blockade of prostaglandin E receptors (EP), EP2, and EP4. Furthermore, the effect of FFSS on COX2, PTGER2, and PTGER4 expression in hPC was quantified. In hPC, stimulation with PGE2 led to an EP2- and EP4-dependent increase in cyclic adenosine monophosphate (cAMP) and COX2, and induced cellular PGE2. PTGER4 was downregulated after PGE2 stimulation in hPC. In the corresponding LC/ESI-MS/MS in vivo analysis at the tissue level, increased PGE2 and 15-keto-PGE2 levels were observed in isolated glomeruli obtained from a well-established rat model with glomerular hyperfiltration, the Munich Wistar Frömter rat. COX2 and PTGER2 were upregulated by FFSS. Our data thus support an autocrine/paracrine COX2/PGE2 pathway in hPC linked to concerted EP2 and EP4 signaling.
Keywords: COX2; EP2; EP4; G protein-coupled receptor (GPCR) signaling; LC/ESI-MS/MS; MWF; SHR; chronic kidney disease; hyperfiltration; podocyte; prostaglandin E2.
Cyclooxygenase-2, prostaglandin E2, and prostanoid receptor EP2 in fluid flow shear stress-mediated injury in the solitary kidney.Am J Physiol Renal Physiol. 2014 Dec 15;307(12):F1323-33. doi: 10.1152/ajprenal.00335.2014. Epub 2014 Sep 18. Am J Physiol Renal Physiol. 2014. PMID: 25234310
Fluid flow shear stress upregulates prostanoid receptor EP2 but not EP4 in murine podocytes.Prostaglandins Other Lipid Mediat. 2013 Jul-Aug;104-105:49-57. doi: 10.1016/j.prostaglandins.2012.11.001. Epub 2012 Dec 20. Prostaglandins Other Lipid Mediat. 2013. PMID: 23262148
Mechanotransduction signaling in podocytes from fluid flow shear stress.Am J Physiol Renal Physiol. 2018 Jan 1;314(1):F22-F34. doi: 10.1152/ajprenal.00325.2017. Epub 2017 Sep 6. Am J Physiol Renal Physiol. 2018. PMID: 28877882 Free PMC article.
Hyperfiltration-associated biomechanical forces in glomerular injury and response: Potential role for eicosanoids.Prostaglandins Other Lipid Mediat. 2017 Sep;132:59-68. doi: 10.1016/j.prostaglandins.2017.01.003. Epub 2017 Jan 17. Prostaglandins Other Lipid Mediat. 2017. PMID: 28108282 Free PMC article. Review.
[Cooperation of two subtypes of PGE2 receptor, Gi coupled EP3 and Gs coupled EP2 or EP4 subtype].Yakugaku Zasshi. 2003 Oct;123(10):837-43. doi: 10.1248/yakushi.123.837. Yakugaku Zasshi. 2003. PMID: 14577329 Review. Japanese.