Modulation of vH+-ATPase is part of the functional adaptation of sheep rumen epithelium to high-energy diet
Modulation of vH+-ATPase is part of the functional adaptation of sheep rumen epithelium to high-energy diet
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DOI：
10.1152/ajpregu.00597.2011
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发表时间：
2012-11-01
影响因子：
2.8
通讯作者：
Schweigel-Roentgen, Monika
中科院分区：
文献类型：
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作者：
Kuzinski, Judith;Zitnan, Rudolf;Schweigel-Roentgen, Monika
[10]李晓，李晓. vH（+）-ATP酶的调节是绵羊瘤胃上皮对高能饮食功能适应的一部分。Am J Physiol Regul Integr Comp Physiol 303：R909-R920，2012年。首次发表于2012年9月12日; doi：10.1152/ajpregu.00597.2011。瘤胃液泡H+-ATP酶（vH（+）-ATP酶）活性受代谢信号的调节。因此，我们测试了其定位，表达和活性是否因不同的喂养而改变。年轻的雄性绵羊（n = 12）喂干草自由采食（h）或干草自由采食加额外的浓缩物（h/c）2周。vH（+）-ATP酶B亚基信号主要分布在基底/副基底型瘤胃上皮细胞（REC）的细胞膜和胞浆中。在h/c饲养的绵羊的瘤胃粘膜中这些细胞的数量增加（3倍）反映了高增殖能力，并且解释了表达vH（+）-ATP酶的REC的总数增加2.3倍。然而，与h/c饲养的绵羊中vH（+）-ATP酶B亚基mRNA表达减少58%一致，其单个REC的蛋白量减少。用荧光探针BCECF和选择性抑制剂（foliomycin，amiloride）研究了vH（+）-ATPase和Na+/H+交换体在细胞内pH（pH（i））调节中的作用。从h/c喂养的绵羊中分离的REC将其pH（i）保持在显著更高的水平（6.91 +/- 0.03对h喂养的绵羊中的6.74 +/- 0.05）。当将Foliomycin或Amiloride应用于来自h-饲喂绵羊的REC时，pH（i）降低0.16 +/- 0.02和0.57 +/- 0.04 pH单位，但在精料饲喂后，效果显著降低（-88和-33%）。然而，我们发现，在Foliomycin诱导的vH（+）-ATP酶抑制后，REC增殖率和[cAMP]（i）降低。我们的研究结果提供了第一个证据vH（+）-ATP酶在调节REC增殖的作用，最有可能是通过连接代谢诱导的pH（i）的变化，调节这一过程的信号通路。
Kuzinski J, Zitnan R, Albrecht E, Viergutz T, Schweigel-Rontgen M. Modulation of vH(+)-ATPase is part of the functional adaptation of sheep rumen epithelium to high-energy diet. Am J Physiol Regul Integr Comp Physiol 303: R909-R920, 2012. First published September 12, 2012; doi:10.1152/ajpregu.00597.2011.-Ruminal vacuolar H+-ATPase (vH(+)-ATPase) activity is regulated by metabolic signals. Thus, we tested whether its localization, expression, and activity were changed by different feeding. Young male sheep (n = 12) were either fed hay ad libitum (h) or hay ad libitum plus additional concentrate (h/c) for 2 wk. The vH(+)-ATPase B subunit signal was predominantly found in the cell membrane and cytosol of rumen epithelial cells (REC) with basal/parabasal phenotype. The elevated number (threefold) of these cells in rumen mucosa of h/c-fed sheep reflects a high proliferative capacity and, explains the 2.3-fold increase of the total number of vH(+)-ATPase-expressing REC. However, in accordance with a 58% reduction of the vH(+)-ATPase B subunit mRNA expression in h/c-fed sheep, its protein amount per single REC was decreased. Using the fluorescent probe BCECF and selective inhibitors (foliomycin, amiloride), the contribution of vH(+)-ATPase and Na+/H+ exchanger to intracellular pH (pH(i)) regulation was investigated. REC isolated from h/c-fed sheep keep their pH(i) at a significantly higher level (6.91 +/- 0.03 vs. 6.74 +/- 0.05 in h-fed sheep). Foliomycin or amiloride decreased pH(i) by 0.16 +/- 0.02 and 0.57 +/- 0.04 pH units when applied to REC from h-fed sheep, but the effects were markedly reduced (-88 and -33%) after concentrate feeding. Nevertheless, we found that REC proliferation rate and [cAMP](i) were reduced after foliomycin-induced vH(+)-ATPase inhibition. Our results provide the first evidence for a role of vH(+)-ATPase in regulation of REC proliferation, most probably by linking metabolically induced pH(i) changes to signaling pathways regulating this process.