Yao Youxiu, Yang Xiaomei, Moore Brittni N, Zhu Tianyue, Lester Laeben, Johns Roger A, Pluznick Jennifer L, Gao Wei Dong
Department of Anesthesiology, Peking University Third Hospital, Beijing, China.
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
FASEB J. 2024 Dec 15;38(23):e70207. doi: 10.1096/fj.202402027R.
G-protein-coupled receptor 41 (GPR41) is a Gα-coupled receptor activated by short-chain fatty acids (SCFAs). Here, we tested that GPR41 is also expressed in cardiomyocytes and exerts a direct negative inotropic effect when activated by SCFA butyrate. Primary cardiomyocytes were isolated from wild-type (WT) and GPR41 knockout (GPR41) adult mice and intracellular Ca concentration and cell shortening were measured using the IonOptix system. RNA localization (RNAScope), quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence staining, and western blot were used to examine the expression of GPR41 in adult primary cardiomyocytes of WT and GPR41 mice. The effect of butyrate on shortening and intracellular Ca transient via GPR41 was also tested in cardiomyocytes. We demonstrated for the first time the presence of GPR41s on cardiomyocytes. Butyrate dose-dependently decreased cell shortening and the amplitude of intracellular Ca transients in cardiomyocytes from WT but not GPR41 mice. In WT cardiomyocytes, butyrate decreased caffeine-mediated amplitudes of intracellular Ca transients from the sarcoplasmic reticulum (SR). Moreover, the inhibitory effects of butyrate on cell shortening and intracellular Ca were pertussis toxin (PTX)-sensitive. Finally, butyrate decreased the activity of sarcoendoplasmic reticulum Ca-ATPase (SERCA) and cellular 3'-5'-cyclic adenosine monophosphate (cAMP) content. In conclusion, GPR41 is expressed on cardiomyocytes. Butyrate, a known GPR41 agonist, reduces cardiomyocyte shortening and intracellular Ca transient via decreasing Ca content in the SR by inhibiting SERCA activity in a PTX-dependent manner. These findings establish that GPR41 is directly activated by SCFAs to decrease contraction and intracellular Ca transient, highlighting the potential inhibitory role of GPR41 in cardiomyocytes.
G蛋白偶联受体41（GPR41）是一种由短链脂肪酸（SCFAs）激活的Gα偶联受体。在此，我们测试了GPR41也在心肌细胞中表达，并且当被SCFA丁酸盐激活时会产生直接的负性肌力作用。从野生型（WT）和GPR41基因敲除（GPR41 -/-）成年小鼠中分离出原代心肌细胞，并使用IonOptix系统测量细胞内钙浓度和细胞缩短情况。采用RNA定位（RNAScope）、定量实时聚合酶链反应（qRT-PCR）、免疫荧光染色和蛋白质免疫印迹法检测WT和GPR41 -/-小鼠成年原代心肌细胞中GPR41的表达。还在心肌细胞中测试了丁酸盐通过GPR41对细胞缩短和细胞内钙瞬变的影响。我们首次证明了心肌细胞上存在GPR41。丁酸盐剂量依赖性地降低了WT小鼠而非GPR41 -/-小鼠心肌细胞的缩短程度和细胞内钙瞬变的幅度值。在WT心肌细胞中，丁酸盐降低了咖啡因介导的肌浆网（SR）细胞内钙瞬变幅度。此外，丁酸盐对细胞缩短和细胞内钙的抑制作用对百日咳毒素（PTX）敏感。最后，丁酸盐降低了肌浆网钙ATP酶（SERCA）的活性和细胞内3'-5'-环磷酸腺苷（cAMP）含量。总之，GPR41在心肌细胞上表达。丁酸盐作为一种已知的GPR41激动剂，通过以PTX依赖的方式抑制SERCA活性来降低SR中的钙含量，从而减少心肌细胞缩短和细胞内钙瞬变。这些发现证实GPR41被SCFAs直接激活，从而降低收缩力和细胞内钙瞬变，突出了GPR41在心肌细胞中的潜在抑制作用。
