A multistep kinase-based sertoli cell autocrine-amplifying loop regulates prostaglandins, their receptors, and cytokines.
In Sertoli epithelial cells, the IL-1beta induces prostaglandins (PG) PGE(2), PGF(2alpha) and PGI(2) (7-, 11-, and 2-fold, respectively), but not PGD(2), production. Cyclohexamide pretreatment inhibiting protein synthesis prevents IL-1beta increases in PG levels, indicating that induction requires de novo protein synthesis. IL-1beta-regulated PGE(2) and PGF(2alpha) production and cytokine expression require activation of cyclooxygenase-2 (COX-2) and c-Jun NH(2)-terminal kinase, as shown using specific enzyme inhibition. PGE(2) and PGF(2alpha) stimulate expression of IL-1alpha, -1beta, and -6, findings consistent with PG involvement in IL signaling within the seminiferous tubule. PGE(2) and PGF(2alpha) reverse COX-2-mediated inhibition of IL-1beta induction of cytokine expression and PG production. Sertoli PG receptor expression was determined; four known E-prostanoid receptor (EP) subtypes (1-4) and the F-prostanoid and prostacyclin prostanoid receptors were demonstrated using RNA and protein analyses. Pharmacological characterization of Sertoli PG receptors associated with cytokine regulation was ascertained by quantitative real-time RT-PCR analyses. IL-1beta regulates both EP(2) mRNA and protein levels, data consistent with a regulatory feedback loop. Butaprost (EP(2) agonist) and 11-deoxy PGE(1) (EP(2) and EP(4) agonist) treatments show that EP(2) receptor activation stimulates Sertoli cytokine expression. Consistent with EP(2)-cAMP signaling, protein kinase A inhibition blocks both IL-1beta- and PGE(2)-induced cytokines. Together, the data indicate an autocrine-amplifying loop involving IL-1beta-regulated Sertoli function mediated by COX-2-induced PGE(2) and PGF(2alpha) production. PGE(2) activates EP(2) and/or EP(4) receptor(s) and the protein kinase A-cAMP pathway; PGF(2alpha) activates F-prostanoid receptor-protein kinase C signaling. Further identification of the molecular mechanisms subserving these mediators may offer new insights into physiological events as well as proinflammatory-mediated pathogenesis in the testis.
Ishikawa
Tomomoto
T
Center for Biomedical Research, Population Council, New York, New York 10021, USA.
Morris
Patricia L
PL
D000818:Animals; D000242:Cyclic AMP / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D051546:Cyclooxygenase 2 / Q000502:physiology; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D007375:Interleukin-1 / Q000494:pharmacology; D008297:Male; D011453:Prostaglandins / Q000096:biosynthesis*; D011493:Protein Kinase C / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011982:Receptors, Prostaglandin / Q000502:physiology*; D012708:Sertoli Cells / Q000378:metabolism*
D016207:Cytokines; D007375:Interleukin-1; D011453:Prostaglandins; D012333:RNA, Messenger; D011982:Receptors, Prostaglandin; D000242:Cyclic AMP; D051546:Cyclooxygenase 2; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C