Role of protein kinase C-delta in the age-dependent secretagogue action of bile acids in mammalian colon.
Role of protein kinase C-delta in the age-dependent secretagogue action of bile acids in mammalian colon.
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蛋白激酶 C-δ 在哺乳动物结肠胆汁酸年龄依赖性促分泌作用中的作用。
DOI：
10.1152/ajpcell.00194.2007
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Rao,MrinaliniC
中科院分区：
文献类型：
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作者：
Kanchanapoo,Jainuch;Ao,Mei;Prasad,Roli;Moore,Christopher;Kay,Cynthia;Piyachaturawat,Pawinee;Rao,MrinaliniC
特异性PKC亚型在钙依赖性促分泌素调节上皮细胞Cl−分泌中的作用仍有争议。在发育中的兔远端结肠中，胆汁酸牛磺脱氧胆酸盐（TDC）通过细胞内钙来刺激成年动物的Cl−转运，而在年轻动物中则不然，而PKC激活剂佛波醇二丁酸酯（PDB）则刺激所有年龄段的Cl−转运。我们测试的假设，具体的PKC亚型占TDC的年龄特异性影响。使用6-甲氧基喹啉乙酰乙酯评估了常规（cPKC）和新型（nPKC）PKC特异性抑制剂对TDC和PDB刺激的成年和断奶结肠细胞Cl−转运的影响。在成年结肠细胞中，cPKC抑制剂Go NPK-6976抑制PDB作用，但不抑制TDC作用，而cPKC和nPKC抑制剂Go NPK-6850阻断TDC和PDB作用。此外，rottlerin和PKC-δ特异性抑制肽（δV1-1）抑制TDC和PDB刺激的成年结肠细胞中的Cl−转运。Rottlerin还降低了完整结肠上皮中TDC刺激的短路电流。在离乳结肠细胞中，只有Go α-6976抑制PDB刺激的转运，而rottlerin和δV1-1均不抑制。结肠裂解物在所有年龄段均表达PKC-α、-λ和-I蛋白，但在任何年龄段均不表达PKC-γ或-θ。PKC-β和PKC-ε蛋白表达为新生>成体>断乳，而PKC-δ在成体表达，断乳和新生结肠不表达。TDC（1.6倍）和PDB（2.0倍）可刺激成年结肠细胞的PKC-δ酶活性，但对断奶结肠细胞无此作用。PKC-δ mRNA表达呈年龄依赖性。因此，PKC-δ似乎是TDC在成年结肠中的作用的关键，并且其在幼年动物中的低表达可能是它们不能响应胆汁酸而分泌的原因。
The role of specific PKC isoforms in the regulation of epithelial Cl−secretion by Ca2+-dependent secretagogues remains controversial. In the developing rabbit distal colon, the bile acid taurodeoxycholate (TDC) acts via intracellular calcium to stimulate Cl−transport in adult, but not in young, animals, whereas the PKC activator phorbol dibutyrate (PDB) stimulates Cl−transport at all ages. We tested the hypothesis that specific PKC isoforms account for the age-specific effects of TDC. The effects of conventional (cPKC) and novel (nPKC) PKC-specific inhibitors on TDC- and PDB-stimulated Cl−transport in adult and weanling colonocytes were assessed by using 6-methoxy-quinolyl acetoethyl ester. In adult colonocytes, the cPKC inhibitor Gö-6976 inhibited PDB action but not TDC action, whereas the cPKC and nPKC inhibitor Gö-6850 blocked both TDC and PDB actions. Additionally, rottlerin and the PKC-δ-specific inhibitor peptide (δV1-1) inhibited TDC- and PDB-stimulated Cl−transport in adult colonocytes. Rottlerin also decreased TDC-stimulated short-circuit current in intact colonic epithelia. Only Gö-6976, but neither rottlerin nor δV1-1, inhibited PDB-stimulated transport in weanling colonocytes. Colonic lysates express PKC-α, -λ, and -ι protein equally at all ages, but they do not express PKC-γ or -θ at any age. Expression of PKC-β and PKC-ε protein was newborn>adult>weanling, whereas PKC-δ was expressed in adult but not in weanling or newborn colonocytes. TDC (1.6-fold) and PDB (2.0-fold) stimulated PKC-δ enzymatic activity in adult colonocytes but failed to do so in weanling colonocytes. PKC-δ mRNA expression showed age dependence. Thus PKC-δ appears critical for the action of TDC in the adult colon, and its low expression in young animals may account for their inability to secrete in response to bile acids.