Biased constitutive signaling of the G protein-coupled receptor GPR35 suppresses gut barrier permeability.

IF 4 2区 生物学 Q2 BIOCHEMISTRY & MOLECULAR BIOLOGY
Journal of Biological Chemistry Pub Date : 2025-01-01 Epub Date: 2024-11-29 DOI:10.1016/j.jbc.2024.108035
Tezz Quon, Li-Chiung Lin, Amlan Ganguly, Brian D Hudson, Andrew B Tobin, Graeme Milligan
{"title":"Biased constitutive signaling of the G protein-coupled receptor GPR35 suppresses gut barrier permeability.","authors":"Tezz Quon, Li-Chiung Lin, Amlan Ganguly, Brian D Hudson, Andrew B Tobin, Graeme Milligan","doi":"10.1016/j.jbc.2024.108035","DOIUrl":null,"url":null,"abstract":"<p><p>Agonist-independent, or constitutive, activity is an integral feature of G protein-coupled receptors, but its relevance in pathophysiological settings is generally poorly explored. GPR35 is a therapeutic target in inflammatory diseases of the lower gut. In colonic organoids from a human GPR35a-expressing transgenic mouse line, the GPR35 inverse agonist CID-2745687 increased barrier permeability substantially, indicating that constitutive receptor activity contributes to maintaining epithelial barrier integrity. High constitutive activity of GPR35 was also observed in both HT-29 and HEPG2 cells that express GPR35 endogenously. Mechanistic investigations in recombinant in vitro systems revealed that the constitutive activity of GPR35a was biased and not equivalent across signaling pathways. Hence, no constitutive interactions of the receptor with arrestin-adaptor proteins or activation of Gα<sub>o</sub>-containing G protein heterotrimers were detected while, even at low GPR35a expression levels, substantial constitutive activation of heterotrimers containing either Gα<sub>12</sub> or Gα<sub>13</sub> was observed. Similar biased constitutive activity was observed for the human GPR35b isoform. The extent of constitutive and agonist-mediated activity was dependent on receptor expression level. At high receptor levels, constitutive activation of Gα<sub>12</sub> or Gα<sub>13</sub> masked any agonist-induced effects while low expression levels with low constitutive activity allowed measurement of agonist-induced responses. These results highlight roles, selectivity, and the extent of constitutive activity of GPR35 in cells and tissues that express this receptor endogenously and highlight the contribution of its constitutive activity to maintaining the colonic epithelial barrier, potentially limiting the development of inflammatory bowel diseases.</p>","PeriodicalId":15140,"journal":{"name":"Journal of Biological Chemistry","volume":" ","pages":"108035"},"PeriodicalIF":4.0000,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732441/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Biological Chemistry","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1016/j.jbc.2024.108035","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/11/29 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0

Abstract

Agonist-independent, or constitutive, activity is an integral feature of G protein-coupled receptors, but its relevance in pathophysiological settings is generally poorly explored. GPR35 is a therapeutic target in inflammatory diseases of the lower gut. In colonic organoids from a human GPR35a-expressing transgenic mouse line, the GPR35 inverse agonist CID-2745687 increased barrier permeability substantially, indicating that constitutive receptor activity contributes to maintaining epithelial barrier integrity. High constitutive activity of GPR35 was also observed in both HT-29 and HEPG2 cells that express GPR35 endogenously. Mechanistic investigations in recombinant in vitro systems revealed that the constitutive activity of GPR35a was biased and not equivalent across signaling pathways. Hence, no constitutive interactions of the receptor with arrestin-adaptor proteins or activation of Gαo-containing G protein heterotrimers were detected while, even at low GPR35a expression levels, substantial constitutive activation of heterotrimers containing either Gα12 or Gα13 was observed. Similar biased constitutive activity was observed for the human GPR35b isoform. The extent of constitutive and agonist-mediated activity was dependent on receptor expression level. At high receptor levels, constitutive activation of Gα12 or Gα13 masked any agonist-induced effects while low expression levels with low constitutive activity allowed measurement of agonist-induced responses. These results highlight roles, selectivity, and the extent of constitutive activity of GPR35 in cells and tissues that express this receptor endogenously and highlight the contribution of its constitutive activity to maintaining the colonic epithelial barrier, potentially limiting the development of inflammatory bowel diseases.

G蛋白偶联受体GPR35的偏向组成信号抑制肠道屏障的通透性。
不依赖于激动剂或组成性的活性是G蛋白偶联受体的一个整体特征,但其在病理生理环境中的相关性通常很少被探索。GPR35是下肠炎性疾病的治疗靶点。在表达gpr35a的人转基因小鼠的结肠类器官中,GPR35逆激动剂CID-2745687显著增加了屏障的通透性,表明构成受体的活性有助于维持上皮屏障的完整性。在内源性表达GPR35的HT-29和HEPG2细胞中也观察到GPR35的高组成活性。重组体外系统的机制研究表明,GPR35a的组成活性是有偏的,并且在信号通路上不相等。因此,没有检测到受体与抑制素衔接蛋白的组成相互作用或含有Gαo的G蛋白异源三聚体的激活,而即使在低GPR35a表达水平下,也观察到含有Gα12或Gα13的异源三聚体的大量组成激活。人类GPR35b异构体也观察到类似的偏构象活性。组成和激动剂介导的活性程度取决于受体的表达水平。在高受体水平下,Gα12或Gα13的组成激活掩盖了任何激动剂诱导的效应,而低表达水平和低组成活性允许测量激动剂诱导的反应。这些结果强调了GPR35在内源性表达该受体的细胞和组织中的作用、选择性和组成活性的程度,并强调了其组成活性对维持结肠上皮屏障的贡献,可能限制炎症性肠病的发展。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Journal of Biological Chemistry
Journal of Biological Chemistry Biochemistry, Genetics and Molecular Biology-Biochemistry
自引率
4.20%
发文量
1233
期刊介绍: The Journal of Biological Chemistry welcomes high-quality science that seeks to elucidate the molecular and cellular basis of biological processes. Papers published in JBC can therefore fall under the umbrellas of not only biological chemistry, chemical biology, or biochemistry, but also allied disciplines such as biophysics, systems biology, RNA biology, immunology, microbiology, neurobiology, epigenetics, computational biology, ’omics, and many more. The outcome of our focus on papers that contribute novel and important mechanistic insights, rather than on a particular topic area, is that JBC is truly a melting pot for scientists across disciplines. In addition, JBC welcomes papers that describe methods that will help scientists push their biochemical inquiries forward and resources that will be of use to the research community.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信