Publikationsdatenbank

Stimulatory effects of butyrate on TRPV3 and TRPV4 with implications for Ca2+ uptake in ruminants (2021)

Art

Poster

Autoren

Liebe, Franziska (WE 2)

Liebe, Hendrik (WE 2)

Mergler, Stefan

Sponder, Gerhard (WE 2)

Stumpff, Friederike (WE 2)

Kongress

100th annual meeting of the German Physiological Society

Frankfurt am Main, 30.09. – 02.10.2021

Quelle

100th annual meeting of the German Physiological Society : book of abstracts : 30.09.– 02.10.2021 Frankfurt am Main — DPG, Deutsche Physiologische Gesellschaft (Hrsg.)

— S. 410

Sprache

Englisch

Verweise

URL (Volltext): https://www.dpg2021.de/wp-content/uploads/DPG2021_Abstract-Book.pdf

Kontakt

Institut für Veterinär-Physiologie

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

Abstract / Zusammenfassung

Microbial fermentation of plant material within the rumen releases large quantities of short-chain fatty acids (SCFA), which stimulate the transport of Ca2+ across the rumen in vivo and in vitro [4,3]and induce a rise in short-circuit current. Although typical Ca2+ channels (TRPV5, TRPV6) are not expressed by the rumen, TRPV3 has emerged as a possible candidate [1,2]. Furthermore, qPCR data suggest expression of TRPV4. We confirm protein expression
of the bovine form of TRPV4 (bTRPV4) by the ruminal epithelium, which could be detected on the level of the protein in Immunoblots, but also via immunofluorescence staining in native ruminal epithelium and model epithelia grown in cell culture. Apart from cytosolic expression, faint staining of the apical membranes was observed. We further investigated effects of Na-butyrate (30 mmol∙L‐1) on bTRPV3 and bTRPV4 via patch-clamp measurements and calcium fluorescence imaging. The effects of Na-butyrate on whole-cell currents tended to be small and variable in both bTRPV4 and non-expressing control cells. Conversely, in cells overexpressing bTRPV3, a strong stimulation on Na+ currents was observed with highest effect at pH 6.4 (p < 0.001 versus bTRPV4 and control). Furthermore, current kinetics were affected with activation of current at positive potentials and pronounced tail-currents upon repolarization. In calcium fluorescence imaging at pH 6.4, initial cytosolic calcium concentration [Ca2+]i was similar in all three cell-types (~ 30 nmol·L-1). In both bTRPV3 and bTRPV4 HEK-293 cells, [Ca2+]i rose to a peak-value within one minute after application of NaBu 6.4, subsequently dropping to a lower plateau of 170 ± 18 (bTRPV3) and 135 ± 7 nmol·L‐1 (bTRPV4) (p < 0.001 versus baseline). In control cells, a significantly smaller increase (p < 0.001) in [Ca2+]i was observed that remained constant at 101 ± 8 nmol·L-1. We conclude that both bTRPV3 and bTRPV4 may contribute to the stimulatory effects of SCFA on the absorption of cations across the rumen.