TRPV3 and TRPV4 as candidate proteins for intestinal ammonium absorption
TRPV3 and TRPV4 as candidate proteins for intestinal ammonium absorption
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DOI：
10.1111/apha.13694
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发表时间：
2021-06-07
影响因子：
6.3
通讯作者：
Stumpff, Friederike
中科院分区：
文献类型：
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作者：
Manneck, David;Braun, Hannah-Sophie;Stumpff, Friederike
目的 肠道吸收氨会产生一系列后果，从肝病中的脑炎到牲畜含氮排泄物引起的全球气候变化。由于膜片钳数据显示瞬时受体电位（TRP）家族的某些成员可渗透NH4+，因此对铵外流的参与进行了研究。方法通过比色法、qPCR、Western blot、免疫组化和Ussing小室对猪的胃、十二指肠、空肠、回肠、盲肠和结肠的消化液、粘膜和肌肉样本进行分析。结果qPCR数据显示TRPV6在十二指肠中高表达。 TRPM6 在空肠和结肠中表达最高，TRPM7 表达普遍存在。 TRPM8 和 TRPV1 低于检测值。 TRPV2 在空肠中最高，但在结肠中几乎检测不到。 TRPV4 普遍表达于粘膜层和肌肉层。 TRPV3 mRNA 仅在盲肠和结肠的粘膜中发现，这些器官中 NH4+ 最高（>7 mmol 中心点 L-1）。免疫组织化学显示，在所有组织中均可检测到 TRPV3 和 TRPV4 的顶端表达，2-APB 和 GSK106790A 的作用支持功能性表达。在对称 NaCl Ringer 中，去除粘膜 Ca2+ 和 Mg2+ 会使结肠短路电流 (I-sc) 和电导 (G(t)) 增加 0.18 +/- 0.06 mu eq center dot cm(-2)center dot h(-1) 和 4.70 +/- 0.85 mS center dot cm(-2) (P < .05，N/n = 4/17)。粘膜 NH4Cl 的应用导致 G(t) 和 I-sc 呈剂量依赖性和二价敏感性增加，在盲肠和结肠中效果最高。结论我们认为 TRP 通道有助于铵的肠道转运，其中 TRPV3 和 TRPV4 有希望成为候选蛋白。药理学调节是可能的。
Aim Absorption of ammonia from the gut has consequences that range from encephalitis in hepatic disease to global climate change induced by nitrogenous excretions from livestock. Since patch clamp data show that certain members of the transient receptor potential (TRP) family are permeable to NH4+, participation in ammonium efflux was investigated.Methods Digesta, mucosa and muscular samples from stomach, duodenum, jejunum, ileum, caecum and colon of pigs were analysed via colourimetry, qPCR, Western blot, immunohistochemistry and Ussing chambers.Results qPCR data show high duodenal expression of TRPV6. TRPM6 was highest in jejunum and colon, with expression of TRPM7 ubiquitous. TRPM8 and TRPV1 were below detection. TRPV2 was highest in the jejunum but almost non-detectable in the colon. TRPV4 was ubiquitously expressed by mucosal and muscular layers. TRPV3 mRNA was only found in the mucosa of the caecum and colon, organs in which NH4+ was highest (>7 mmol center dot L-1). Immunohistochemically, an apical expression of TRPV3 and TRPV4 could be detected in all tissues, with effects of 2-APB and GSK106790A supporting functional expression. In symmetrical NaCl Ringer, removal of mucosal Ca2+ and Mg2+ increased colonic short circuit current (I-sc) and conductance (G(t)) by 0.18 +/- 0.06 mu eq center dot cm(-2)center dot h(-1) and 4.70 +/- 0.85 mS center dot cm(-2) (P < .05, N/n = 4/17). Application of mucosal NH4Cl led to dose-dependent and divalent-sensitive increases in G(t) and I-sc, with effects highest in the caecum and colon.Conclusion We propose that TRP channels contribute to the intestinal transport of ammonium, with TRPV3 and TRPV4 promising candidate proteins. Pharmacological regulation may be possible.