Publikationsdatenbank

Effects of butyrate- on ruminal Ca2+ transport:
evidence for the involvement of apically expressed TRPV3 and TRPV4 channels (2022)

Art

Zeitschriftenartikel / wissenschaftlicher Beitrag

Autoren

Liebe, Franziska (WE 2)

Liebe, Hendrik (WE 2)

Sponder, Gerhard (WE 2)

Mergler, Stefan

Stumpff, Friederike (WE 2)

Quelle

Pflügers Archiv : European journal of physiology

Bandzählung: 474

Heftzählung: 3

Seiten: 315 – 342

ISSN: 1432-2013

Sprache

Englisch

Verweise

URL (Volltext): https://link.springer.com/article/10.1007/s00424-021-02647-7

DOI: 10.1007/s00424-021-02647-7

Pubmed: 35098357

Kontakt

Institut für Veterinär-Physiologie

Oertzenweg 19 b
14163 Berlin
+49 30 838 62600
physiologie@vetmed.fu-berlin.de

Abstract / Zusammenfassung

The ruminal epithelium absorbs large quantities of NH4+ and Ca2+. A role for TRPV3 has emerged, but data on TRPV4 are lacking. Furthermore, short-chain fatty acids (SCFA) stimulate ruminal Ca2+ and NH4+ uptake in vivo and in vitro, but the pathway is unclear. Sequencing of the bovine homologue (bTRPV4) revealed 96.79% homology to human TRPV4. Two commercial antibodies were tested using HEK-293 cells overexpressing bTRPV4, which in ruminal protein detected a weak band at the expected ~ 100 kDa and several bands ≤ 60 kDa. Immunofluorescence imaging revealed staining of the apical membrane of the stratum granulosum for bTRPV3 and bTRPV4, with cytosolic staining in other layers of the ruminal epithelium. A similar expression pattern was observed in a multilayered ruminal cell culture which developed resistances of > 700 Ω · cm2 with expression of zonula occludens-1 and claudin-4. In Ussing chambers, 2-APB and the TRPV4 agonist GSK1016790A stimulated the short-circuit current across native bovine ruminal epithelia. In whole-cell patch-clamp recordings on HEK-293 cells, bTRPV4 was shown to be permeable to NH4+, K+, and Na+ and highly sensitive to GSK1016790A, while effects of butyrate- were insignificant. Conversely, bTRPV3 was strongly stimulated by 2-APB and by butyrate- (pH 6.4 > pH 7.4), but not by GSK1016790A. Fluorescence calcium imaging experiments suggest that butyrate- stimulates both bTRPV3 and bTRPV4. While expression of bTRPV4 appears to be weaker, both channels are candidates for the ruminal transport of NH4+ and Ca2+. Stimulation by SCFA may involve cytosolic acidification (bTRPV3) and cell swelling (bTRPV4).