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Wan H, Li J, Chen X, Sellers ZM, Dong H. Divergent roles of estrogen receptor subtypes in regulating estrogen-modulated colonic ion transports and epithelial repair. J Biol Chem 2023; 299:105068. [PMID: 37468102 PMCID: PMC10448179 DOI: 10.1016/j.jbc.2023.105068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023] Open
Abstract
Although it was described previously for estrogen (E2) regulation of intestinal epithelial Cl- and HCO3- secretion in sex difference, almost nothing is known about the roles of estrogen receptor (ER) subtypes in regulating E2-modulated epithelial ion transports and epithelial restitution. Here, we aimed to investigate ERα and ERβ subtypes in the regulation of E2-modulated colonic epithelial HCO3- and Cl- secretion and epithelial restitution. Through physiological and biochemical studies, in combination of genetic knockdown, we showed that ERα attenuated female colonic Cl- secretion but promoted Ca2+-dependent HCO3- secretion via store-operated calcium entry (SOCE) mechanism in mice. However, ERβ attenuated HCO3- secretion by inhibiting Ca2+via the SOCE and inhibiting cAMP via protein kinases. Moreover, ERα but not ERβ promoted epithelial cell restitution via SOCE/Ca2+ signaling. ERα also enhanced cyclin D1, proliferating cell nuclear antigen, and β-catenin expression in normal human colonic epithelial cells. All ERα-mediated biological effects could be attenuated by its selective antagonist and genetic knockdown. Finally, both ERα and ERβ were expressed in human colonic epithelial cells and mouse colonic tissues. We therefore conclude that E2 modulates complex colonic epithelial HCO3- and Cl- secretion via ER subtype-dependent mechanisms and that ERα is specifically responsible for colonic epithelial regeneration. This study provides novel insights into the molecular mechanisms of how ERα and ERβ subtypes orchestrate functional homeostasis of normal colonic epithelial cells.
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Affiliation(s)
- Hanxing Wan
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China; Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Junhui Li
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China
| | - Xiongying Chen
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China
| | - Zachary M Sellers
- Pediatric Gastroenterology Hepatology & Nutrition, Stanford University School of Medicine, Palo Alto, California, USA.
| | - Hui Dong
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China.
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2
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Krishnan V, Ali S, Gonzales AL, Thakore P, Griffin CS, Yamasaki E, Alvarado MG, Johnson MT, Trebak M, Earley S. STIM1-dependent peripheral coupling governs the contractility of vascular smooth muscle cells. eLife 2022; 11:70278. [PMID: 35147077 PMCID: PMC8947769 DOI: 10.7554/elife.70278] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 02/10/2022] [Indexed: 11/28/2022] Open
Abstract
Peripheral coupling between the sarcoplasmic reticulum (SR) and plasma membrane (PM) forms signaling complexes that regulate the membrane potential and contractility of vascular smooth muscle cells (VSMCs). The mechanisms responsible for these membrane interactions are poorly understood. In many cells, STIM1 (stromal interaction molecule 1), a single-transmembrane-domain protein that resides in the endoplasmic reticulum (ER), transiently moves to ER-PM junctions in response to depletion of ER Ca2+ stores and initiates store-operated Ca2+ entry (SOCE). Fully differentiated VSMCs express STIM1 but exhibit only marginal SOCE activity. We hypothesized that STIM1 is constitutively active in contractile VSMCs and maintains peripheral coupling. In support of this concept, we found that the number and size of SR-PM interacting sites were decreased, and SR-dependent Ca2+-signaling processes were disrupted in freshly isolated cerebral artery SMCs from tamoxifen-inducible, SMC-specific STIM1-knockout (Stim1-smKO) mice. VSMCs from Stim1-smKO mice also exhibited a reduction in nanoscale colocalization between Ca2+-release sites on the SR and Ca2+-activated ion channels on the PM, accompanied by diminished channel activity. Stim1-smKO mice were hypotensive, and resistance arteries isolated from them displayed blunted contractility. These data suggest that STIM1 – independent of SR Ca2+ store depletion – is critically important for stable peripheral coupling in contractile VSMCs.
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Affiliation(s)
- Vivek Krishnan
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Sher Ali
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Albert L Gonzales
- Department of Physiology and Cell Biology, University of Nevada Reno, Reno, United States
| | - Pratish Thakore
- Department of Pharmacology, University of Nevada, Reno, Reno, United States
| | - Caoimhin S Griffin
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Evan Yamasaki
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Michael G Alvarado
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Martin T Johnson
- Department of Cellular and Molecular Physiology, Penn State University, Hershey, United States
| | - Mohamed Trebak
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, United States
| | - Scott Earley
- Department of Pharmacology, University of Nevada Reno, Reno, United States
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3
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Cui Y, Chu F, Yin K, Chen X, Wan H, Luo G, Dong H, Xu F. Role of Serosal TRPV4-Constituted SOCE Mechanism in Secretagogues-Stimulated Intestinal Epithelial Anion Secretion. Front Pharmacol 2021; 12:684538. [PMID: 34335254 PMCID: PMC8317263 DOI: 10.3389/fphar.2021.684538] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/24/2021] [Indexed: 12/05/2022] Open
Abstract
As little is known about the role of calcium (Ca2+) signaling mediating the small intestinal epithelial anion secretion, we aimed to study its regulatory role in secretagogue-stimulated duodenal anion secretion and the underlying molecular mechanisms. Therefore, intestinal anion secretion from native mouse duodenal epithelia was examined with Ussing chambers to monitor PGE2-, 5-HT-, and CCh-induced short-circuit currents (Isc). PGE2 (10 μM) and 5-HT (10 μM) induced mouse duodenal Isc, markedly attenuated by serosal Ca2+-free solution and selective blockers of store-operated Ca2+ channels on the serosal side of the duodenum. Furthermore, PGE2- and 5-HT-induced duodenal Isc was also inhibited by ER Ca2+ chelator TPEN. However, dantrolene, a selective blocker of ryanodine receptors, inhibited PGE2-induced duodenal Isc, while LiCl, an inhibitor of IP3 production, inhibited 5-HT-induced Isc. Moreover, duodenal Isc response to the serosal applications of both PGE2 and 5-HT was significantly attenuated in transient receptor potential vanilloid 4 (TRPV4) knockout mice. Finally, mucosal application of carbachol (100 μM) also induced duodenal Isc via selective activation of muscarinic receptors, which was significantly inhibited in serosal Ca2+-free solution but neither in mucosal Ca2+-free solution nor by nifedipine. Therefore, the serosal TRPV4-constituted SOCE mechanism is likely universal for the most common and important secretagogues-induced and Ca2+-dependent intestinal anion secretion. These findings will enhance our knowledge about gastrointestinal (G.I.) epithelial physiology and the associated G.I. diseases, such as diarrhea and constipation.
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Affiliation(s)
- Yinghui Cui
- Department of Pediatric Intensive Care Unit, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders; Ministry of Education Key Laboratory of Child Development and Disorders; Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Fenglan Chu
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Kai Yin
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Xiongying Chen
- Department of Pediatric Intensive Care Unit, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders; Ministry of Education Key Laboratory of Child Development and Disorders; Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Hanxing Wan
- Department of Pediatric Intensive Care Unit, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders; Ministry of Education Key Laboratory of Child Development and Disorders; Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Gang Luo
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hui Dong
- Department of Pediatric Intensive Care Unit, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders; Ministry of Education Key Laboratory of Child Development and Disorders; Chongqing Key Laboratory of Pediatrics, Chongqing, China.,Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Feng Xu
- Department of Pediatric Intensive Care Unit, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders; Ministry of Education Key Laboratory of Child Development and Disorders; Chongqing Key Laboratory of Pediatrics, Chongqing, China
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Wongdee K, Chanpaisaeng K, Teerapornpuntakit J, Charoenphandhu N. Intestinal Calcium Absorption. Compr Physiol 2021; 11:2047-2073. [PMID: 34058017 DOI: 10.1002/cphy.c200014] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this article, we focus on mammalian calcium absorption across the intestinal epithelium in normal physiology. Intestinal calcium transport is essential for supplying calcium for metabolism and bone mineralization. Dietary calcium is transported across the mucosal epithelia via saturable transcellular and nonsaturable paracellular pathways, both of which are under the regulation of 1,25-dihydroxyvitamin D3 and several other endocrine and paracrine factors, such as parathyroid hormone, prolactin, 17β-estradiol, calcitonin, and fibroblast growth factor-23. Calcium absorption occurs in several segments of the small and large intestine with varying rates and capacities. Segmental heterogeneity also includes differential expression of calcium transporters/carriers (e.g., transient receptor potential cation channel and calbindin-D9k ) and the presence of favorable factors (e.g., pH, luminal contents, and gut motility). Other proteins and transporters (e.g., plasma membrane vitamin D receptor and voltage-dependent calcium channels), as well as vesicular calcium transport that probably contributes to intestinal calcium absorption, are also discussed. © 2021 American Physiological Society. Compr Physiol 11:1-27, 2021.
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Affiliation(s)
- Kannikar Wongdee
- Faculty of Allied Health Sciences, Burapha University, Chonburi, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Krittikan Chanpaisaeng
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Jarinthorn Teerapornpuntakit
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.,The Academy of Science, The Royal Society of Thailand, Bangkok, Thailand
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Shan W, Hu Y, Ding J, Yang X, Lou J, Du Q, Liao Q, Luo L, Xu J, Xie R. Advances in Ca 2+ modulation of gastrointestinal anion secretion and its dysregulation in digestive disorders (Review). Exp Ther Med 2020; 20:8. [PMID: 32934673 PMCID: PMC7471861 DOI: 10.3892/etm.2020.9136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/22/2020] [Indexed: 11/29/2022] Open
Abstract
Intracellular calcium (Ca2+) is a critical cell signaling component in gastrointestinal (GI) physiology. Cytosolic calcium ([Ca2+]cyt), as a secondary messenger, controls GI epithelial fluid and ion transport, mucus and neuropeptide secretion, as well as synaptic transmission and motility. The key roles of Ca2+ signaling in other types of secretory cell (including those in the airways and salivary glands) are well known. However, its action in GI epithelial secretion and the underlying molecular mechanisms have remained to be fully elucidated. The present review focused on the role of [Ca2+]cyt in GI epithelial anion secretion. Ca2+ signaling regulates the activities of ion channels and transporters involved in GI epithelial ion and fluid transport, including Cl- channels, Ca2+-activated K+ channels, cystic fibrosis (CF) transmembrane conductance regulator and anion/HCO3- exchangers. Previous studies by the current researchers have focused on this field over several years, providing solid evidence that Ca2+ signaling has an important role in the regulation of GI epithelial anion secretion and uncovering underlying molecular mechanisms. The present review is largely based on previous studies by the current researchers and provides an overview of the currently known molecular mechanisms of GI epithelial anion secretion with an emphasis on Ca2+-mediated ion secretion and its dysregulation in GI disorders. In addition, previous studies by the current researchers demonstrated that different regulatory mechanisms are in place for GI epithelial HCO3- and Cl- secretion. An increased understanding of the roles of Ca2+ signaling and its targets in GI anion secretion may lead to the development of novel strategies to inhibit GI diseases, including the enhancement of fluid secretion in CF and protection of the GI mucosa in ulcer diseases.
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Affiliation(s)
- Weixi Shan
- Department of Gastroenterology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Yanxia Hu
- Department of Gastroenterology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Jianhong Ding
- Department of Gastroenterology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Xiaoxu Yang
- Department of Gastroenterology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Jun Lou
- Department of Gastroenterology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Qian Du
- Department of Gastroenterology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Qiushi Liao
- Department of Gastroenterology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Lihong Luo
- Department of Oncology and Geriatrics, Traditional Chinese Medicine Hospital of Chishui City, Guizhou 564700, P.R. China
| | - Jingyu Xu
- Department of Gastroenterology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Rui Xie
- Department of Gastroenterology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
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6
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Zhang F, Wan H, Yang X, He J, Lu C, Yang S, Tuo B, Dong H. Molecular mechanisms of caffeine-mediated intestinal epithelial ion transports. Br J Pharmacol 2019; 176:1700-1716. [PMID: 30808064 DOI: 10.1111/bph.14640] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 01/10/2019] [Accepted: 01/31/2019] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE As little is known about the effect of caffeine, one of the most widely consumed substances worldwide, on intestinal function, we aimed to study its action on intestinal anion secretion and the underlying molecular mechanisms. EXPERIMENTAL APPROACH Anion secretion and channel expression were examined in mouse duodenal epithelium by Ussing chambers and immunocytochemistry. Ca2+ imaging was also performed in intestinal epithelial cells (IECs). KEY RESULTS Caffeine (10 mM) markedly increased mouse duodenal short-circuit current (Isc ), which was attenuated by a removal of either Cl- or HCO3 - , Ca2+ -free serosal solutions and selective blockers of store-operated Ca2+ channels (SOC/Ca2+ release-activated Ca2+ channels), and knockdown of Orai1 channels on the serosal side of duodenal tissues. Caffeine induced SOC entry in IEC, which was inhibited by ruthenium red and selective blockers of SOC. Caffeine-stimulated duodenal Isc was inhibited by the endoplasmic reticulum Ca2+ chelator (N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine), selective blockers (ruthenium red and dantrolene) of ryanodine receptors (RyR), and of Ca2+ -activated Cl- channels (niflumic acid and T16A). There was synergism between cAMP and Ca2+ signalling, in which cAMP/PKA promoted caffeine/Ca2+ -mediated anion secretion. Expression of STIM1 and Orai1 was detected in mouse duodenal mucosa and human IECs. The Orai1 proteins were primarily co-located with the basolateral marker Na+ , K+ -ATPase. CONCLUSIONS AND IMPLICATIONS Caffeine stimulated intestinal anion secretion mainly through the RyR/Orai1/Ca2+ signalling pathway. There is synergism between cAMP/PKA and caffeine/Ca2+ -mediated anion secretion. Our findings suggest that a caffeine-mediated RyR/Orai1/Ca2+ pathway could provide novel potential drug targets to control intestinal anion secretion.
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Affiliation(s)
- Fenglian Zhang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Hanxing Wan
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Xin Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Jialin He
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Cheng Lu
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Shiming Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, and Digestive Disease Institute of Guizhou Province, Zunyi, China
| | - Hui Dong
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China.,Department of Medicine, School of Medicine, University of California, San Diego, California, USA
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7
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Yang X, Wen G, Tuo B, Zhang F, Wan H, He J, Yang S, Dong H. Molecular mechanisms of calcium signaling in the modulation of small intestinal ion transports and bicarbonate secretion. Oncotarget 2017; 9:3727-3740. [PMID: 29423078 PMCID: PMC5790495 DOI: 10.18632/oncotarget.23197] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/01/2017] [Indexed: 01/13/2023] Open
Abstract
Background and Purpose: Although Ca2+ signaling may stimulate small intestinal ion secretion, little is known about its critical role and the molecular mechanisms of Ca2+-mediated biological action. Key Results Activation of muscarinic receptors by carbachol(CCh) stimulated mouse duodenal Isc, which was significantly inhibited in Ca2+-free serosal solution and by several selective store-operated Ca2+ channels(SOC) blockers added to the serosal side of duodenal tissues. Furthermore, we found that CRAC/Orai channels may represent the molecular candidate of SOC in intestinal epithelium. CCh increased intracellular Ca2+ but not cAMP, and Ca2+ signaling mediated duodenal Cl- and HCO3- secretion in wild type mice but not in CFTR knockout mice. CCh induced duodenal ion secretion and stimulated PI3K/Akt activity in duodenal epithelium, all of which were inhibited by selective PI3K inhibitors with different structures. CCh-induced Ca2+ signaling also stimulated the phosphorylation of CFTR proteins and their trafficking to the plasma membrane of duodenal epithelial cells, which were inhibited again by selective PI3K inhibitors. Materials and Methods Functional, biochemical and morphological experiments were performed to examine ion secretion, PI3K/Akt and CFTR activity of mouse duodenal epithelium. Ca2+ imaging was performed on HT-29 cells. Conclusions and Implications Ca2+ signaling plays a critical role in intestinal ion secretion via CRAC/Orai-mediated SOCE mechanism on the serosal side of epithelium. We also demonstrated the molecular mechanisms of Ca2+ signaling in CFTR-mediated secretion via novel PI3K/Akt pathway. Our findings suggest new perspectives for drug targets to protect the upper GI tract and control liquid homeostasis in the small intestine.
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Affiliation(s)
- Xin Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Guorong Wen
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, and Digestive Disease Institute of Guizhou Province, Zunyi 563003, China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, and Digestive Disease Institute of Guizhou Province, Zunyi 563003, China
| | - Fenglian Zhang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Hanxing Wan
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Jialin He
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Shiming Yang
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, and Digestive Disease Institute of Guizhou Province, Zunyi 563003, China
| | - Hui Dong
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.,Department of Medicine, School of Medicine, University of California, San Diego, CA 92093, USA
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Clostridium difficile toxin CDT hijacks microtubule organization and reroutes vesicle traffic to increase pathogen adherence. Proc Natl Acad Sci U S A 2014; 111:2313-8. [PMID: 24469807 DOI: 10.1073/pnas.1311589111] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile causes antibiotic-associated diarrhea and pseudomembranous colitis by the actions of Rho-glucosylating toxins A and B. Recently identified hypervirulent strains, which are associated with increased morbidity and mortality, additionally produce the actin-ADP-ribosylating toxin C. difficile transferase (CDT). CDT depolymerizes actin, causes formation of microtubule-based protrusions, and increases pathogen adherence. Here we show that CDT-induced protrusions allow vesicle traffic and contain endoplasmic reticulum tubules, connected to microtubules via the calcium sensor Stim1. The toxin reroutes Rab11-positive vesicles containing fibronectin, which is involved in bacterial adherence, from basolateral to the apical membrane sides in a microtubule- and Stim1-dependent manner. The data yield a model of C. difficile adherence regulated by actin depolymerization, microtubule restructuring, subsequent Stim1-dependent Ca(2+) signaling, vesicle rerouting, and secretion of ECM proteins to increase bacterial adherence.
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