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Castro-Martinez F, Candelario-Martinez A, Encarnacion-Garcia MR, Piedra-Quintero Z, Bonilla-Moreno R, Betanzos A, Perez-Orozco R, Hernandez-Cueto MA, Muñoz-Medina JE, Patiño-Lopez G, Schnoor M, Villegas-Sepulveda N, Nava P. Rictor/Mammalian Target of Rapamycin Complex 2 Signaling Protects Colonocytes from Apoptosis and Prevents Epithelial Barrier Breakdown. Am J Pathol 2021; 191:1537-1549. [PMID: 34139193 DOI: 10.1016/j.ajpath.2021.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/18/2021] [Accepted: 06/07/2021] [Indexed: 11/29/2022]
Abstract
Epithelial barrier impairment is a hallmark of several pathologic processes in the gut, including inflammatory bowel diseases. Several intracellular signals prevent apoptosis in intestinal epithelial cells. Herein, we show that in colonocytes, rictor/mammalian target of rapamycin complex 2 (mTORC2) signaling is a prosurvival stimulus. Mechanistically, mTORC2 activates Akt, which, in turn, inhibits apoptosis by phosphorylating B-cell lymphoma 2 (BCL2) associated agonist of cell death (Bad) and preventing caspase-3 activation. Nevertheless, during inflammation, rictor/mTORC2 signaling declines and Akt activity is reduced. Consequently, active caspase-3 increases in surface colonocytes undergoing apoptosis/anoikis and causes epithelial barrier breakdown. Likewise, Rictor ablation in intestinal epithelial cells interrupts mTORC2/Akt signaling and increases apoptosis/anoikis of surface colonocytes without affecting the crypt architecture. The increase in epithelial permeability induced by Rictor ablation produces a mild inflammatory response in the colonic mucosa, but minimally affects the development/establishment of colitis. The data identify a previously unknown mechanism by which rictor/mTORC2 signaling regulates apoptosis/anoikis in intestinal epithelial cells during colitis and clarify its role in the maintenance of the intestinal epithelial barrier.
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Affiliation(s)
- Felipe Castro-Martinez
- Departments of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Aurora Candelario-Martinez
- Departments of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Maria R Encarnacion-Garcia
- Departments of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Zayda Piedra-Quintero
- Department of Molecular Biomedicine, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Raul Bonilla-Moreno
- Department of Molecular Biomedicine, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Abigail Betanzos
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Rocio Perez-Orozco
- Medicine Program for the Teaching and Development of Scientific Research in Iztacala (MEDICI Program), Faculty of Advanced Studies Iztacala, National Autonomous University of Mexico, Mexico-City, Mexico
| | - Maria A Hernandez-Cueto
- Central Laboratory of Epidemiology, Mexican. Institute of Social Security, Mexico-City, Mexico
| | - Jose E Muñoz-Medina
- Central Laboratory of Epidemiology, Mexican. Institute of Social Security, Mexico-City, Mexico
| | - Genaro Patiño-Lopez
- Laboratory of Research in Immunology and Proteomics, Federico Gómez Children's Hospital of Mexico, Mexico-City, Mexico
| | - Michael Schnoor
- Department of Molecular Biomedicine, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico
| | - Nicolas Villegas-Sepulveda
- Department of Molecular Biomedicine, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico.
| | - Porfirio Nava
- Departments of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies- National Polytechnic Institute (CINVESTAV-IPN), Mexico-City, Mexico.
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