Nicotinic acetylcholine receptors are sensors for ethanol in lung fibroblasts.
Nicotinic acetylcholine receptors are sensors for ethanol in lung fibroblasts.
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DOI：
10.1111/acer.12044
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发表时间：
2013-06
期刊：
影响因子：
--
通讯作者：
Roman J
中科院分区：
文献类型：
--
作者：
Ritzenthaler JD;Roser-Page S;Guidot DM;Roman J
已知人类慢性乙醇滥用可单独增加高危个体急性肺损伤的发生率和死亡率。然而，乙醇影响肺细胞的机制仍未完全阐明。在早期的研究中，我们报道了乙醇增加了肺成纤维细胞中纤维连接蛋白的表达，纤维连接蛋白是一种与肺损伤和修复有关的基质糖蛋白。这种作用被α-班加罗毒素阻断，这是一种结合某些烟碱乙酰胆碱受体（nachr）的神经毒素，从而暗示nachr参与了这一过程。在这里，我们检查这些受体的身份。用乙醇（60 mM）或乙酰胆碱（100-500 μM）刺激小鼠肺成纤维细胞，观察纤维连接蛋白和nachr的表达。使用nachr抑制剂或抗氧化剂n -乙酰半胱氨酸来评估纤维连接蛋白表达的变化。动物暴露于乙醇长达6周，用于评估体内nachr的表达。首先，在乙醇处理的成纤维细胞中，我们观察到α4和α9 nAChR亚基的表达增加。其次，我们发现乙酰胆碱，nachr的天然配体，模仿乙醇的作用。二氢β-红素氢溴化物（DβH）是α4 nAChR的竞争性抑制剂，可抑制纤维连接蛋白表达的增加和细胞增殖。此外，在α4 nAChR沉默的细胞中，乙醇诱导的纤维连接蛋白表达被抑制。然而，乙醇处理的细胞显示α-班加罗毒素结合增加，这表明α4 nAChR通过不依赖配体的途径介导乙醇的作用。我们知道在α4 nAChRs的配体结合位点附近有几个重要的半胱氨酸残基，我们测试了抗氧化剂n -乙酰半胱氨酸，发现它也阻断了乙醇对纤维连接蛋白表达的诱导。此外，暴露于氧化应激的成纤维细胞显示α-班加罗毒素阻断的纤维连接蛋白表达增加。最后，我们发现暴露于乙醇的小鼠和大鼠肺组织中α4 nachr的表达增加，这表明这些受体在体内发挥了作用。总之，我们的观察结果表明α4 nAChRs在肺成纤维细胞中作为乙醇诱导氧化应激的传感器，从而揭示了乙醇可能影响肺细胞和组织重塑的新机制，并指出nAChRs可能是干预的潜在靶点。
Chronic ethanol abuse in humans is known to independently increase the incidence of and mortality due to acute lung injury in at-risk individuals. However, the mechanisms by which ethanol affects lung cells remain incompletely elucidated. In earlier work, we reported that ethanol increased the expression in lung fibroblasts of fibronectin, a matrix glycoprotein implicated in lung injury and repair. This effect was blocked by α-bungarotoxin, a neurotoxin that binds certain nicotinic acetylcholine receptors (nAChRs) thereby implicating nAChRs in this process. Here, we examine the identity of these receptors. Mouse lung fibroblasts were stimulated with ethanol (60 mM) or acetylcholine (100–500 μM) and evaluated for the expression of fibronectin and nAChRs. Inhibitors to nAChRs or the antioxidant N-acetyl cysteine were used to assess changes in fibronectin expression. Animals exposed to ethanol for up to 6 weeks were used to evaluate the expression of nAChRs in vivo. First, in ethanol-treated fibroblasts, we observed increased expression of α4 and α9 nAChR subunits. Second, we found that acetylcholine, a natural ligand for nAChRs, mimicked the effects of ethanol. Dihydro-β-erythroidin hydrobromide (DβH), a competitive inhibitor of α4 nAChR, blocked the increase in fibronectin expression and cell proliferation. Furthermore, ethanol-induced fibronectin expression was inhibited in cells silenced for α4 nAChR. However, ethanol-treated cells showed increased α-bungarotoxin binding suggesting that α4 nAChR mediates the effects of ethanol via a ligand-independent pathway. Knowing there are several important cysteine residues near the ligand binding site of α4 nAChRs, we tested the antioxidant N-acetyl cysteine and found that it too blocked the induction of fibronectin expression by ethanol. Also, fibroblasts exposed to oxidant stress showed increased fibronectin expression that was blocked with α-bungarotoxin. Finally, we showed increased expression of α4 nAChRs in the lung tissue of mice and rats exposed to ethanol suggesting a role for these receptors in vivo. Altogether, our observations suggest that α4 nAChRs serve as sensors for ethanol-induced oxidant stress in lung fibroblasts, thereby revealing a new mechanism by which ethanol may affect lung cells and tissue remodeling, and pointing to nAChRs as potential targets for intervention.
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影响因子：
5
作者：
Bagnardi, Vincenzo;Randi, Giorgia;Landi, Maria Teresa
通讯作者：
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影响因子：
2.5
作者：
Hiemke, C;Stolp, M;Schroder, H
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DOI：
10.1164/ajrccm.160.4.9811060
发表时间：
1999-10-01
影响因子：
24.7
作者：
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通讯作者：
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影响因子：
4.4
作者：
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通讯作者：
Barrantes, FJ
DOI：
10.1152/ajplung.00445.2000
发表时间：
2002-02-01
影响因子：
4.9
作者：
Michaelson, JE;Ritzenthaler, JD;Roman, J
通讯作者：
Roman, J