1
|
Beltrán AR, Carraro-Lacroix LR, Bezerra CNA, Cornejo M, Norambuena K, Toledo F, Araos J, Pardo F, Leiva A, Sanhueza C, Malnic G, Sobrevia L, Ramírez MA. Escherichia coli Heat-Stable Enterotoxin Mediates Na+/H+ Exchanger 4 Inhibition Involving cAMP in T84 Human Intestinal Epithelial Cells. PLoS One 2015; 10:e0146042. [PMID: 26713849 PMCID: PMC4699896 DOI: 10.1371/journal.pone.0146042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/11/2015] [Indexed: 01/05/2023] Open
Abstract
The enterotoxigenic Escherichia coli strains lead to diarrhoea in humans due to heat-labile and heat-stable (STa) enterotoxins. STa increases Cl-release in intestinal cells, including the human colonic carcinoma T84 cell line, involving increased cGMP and membrane alkalization due to reduced Na+/H+ exchangers (NHEs) activity. Since NHEs modulate intracellular pH (pHi), and NHE1, NHE2, and NHE4 are expressed in T84 cells, we characterized the STa role as modulator of these exchangers. pHi was assayed by the NH4Cl pulse technique and measured by fluorescence microscopy in BCECF-preloaded cells. pHi recovery rate (dpHi/dt) was determined in the absence or presence of 0.25 μmol/L STa (30 minutes), 25 μmol/L HOE-694 (concentration inhibiting NHE1 and NHE2), 500 μmol/L sodium nitroprusside (SNP, spontaneous nitric oxide donor), 100 μmol/L dibutyryl cyclic GMP (db-cGMP), 100 nmol/L H89 (protein kinase A inhibitor), or 10 μmol/L forskolin (adenylyl cyclase activator). cGMP and cAMP were measured in cell extracts by radioimmunoassay, and buffering capacity (ßi) and H+ efflux (JH+) was determined. NHE4 protein abundance was determined by western blotting. STa and HOE-694 caused comparable reduction in dpHi/dt and JH+ (~63%), without altering basal pHi (range 7.144-7.172). STa did not alter ßi value in a range of 1.6 pHi units. The dpHi/dt and JH+ was almost abolished (~94% inhibition) by STa + HOE-694. STa effect was unaltered by db-cGMP or SNP. However, STa and forskolin increased cAMP level. STa-decreased dpHi/dt and JH+ was mimicked by forskolin, and STa + HOE-694 effect was abolished by H89. Thus, incubation of T84 cells with STa results in reduced NHE4 activity leading to a lower capacity of pHi recovery requiring cAMP, but not cGMP. STa effect results in a causal phenomenon (STa/increased cAMP/increased PKA activity/reduced NHE4 activity) ending with intracellular acidification that could have consequences in the gastrointestinal cells function promoting human diarrhoea.
Collapse
Affiliation(s)
- Ana R. Beltrán
- Cellular Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta 1270300, Chile
- Department of Education, Faculty of Education, Universidad de Antofagasta, Antofagasta 1270300, Chile
| | - Luciene R. Carraro-Lacroix
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo 3550308–1009, Brazil
| | - Camila N. A. Bezerra
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo 3550308–1009, Brazil
| | - Marcelo Cornejo
- Cellular Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta 1270300, Chile
| | - Katrina Norambuena
- Cellular Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta 1270300, Chile
| | - Fernando Toledo
- Department of Basic Sciences, Faculty of Sciences, Universidad del Bío-Bío, Chillán 3780000, Chile
| | - Joaquín Araos
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Fabián Pardo
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Andrea Leiva
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Carlos Sanhueza
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Gerhard Malnic
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo 3550308–1009, Brazil
| | - Luis Sobrevia
- Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain
- University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, QLD 4029, Queensland, Australia
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
- * E-mail: (MAR); (LS)
| | - Marco A. Ramírez
- Cellular Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta 1270300, Chile
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
- * E-mail: (MAR); (LS)
| |
Collapse
|
2
|
Jin LG, Chu JJ, Pang QF, Zhang FZ, Wu G, Zhou LY, Zhang XJ, Xing CG. Caffeic acid phenethyl ester attenuates ionize radiation-induced intestinal injury through modulation of oxidative stress, apoptosis and p38MAPK in rats. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:156-163. [PMID: 26122083 DOI: 10.1016/j.etap.2015.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 05/26/2015] [Accepted: 05/26/2015] [Indexed: 06/04/2023]
Abstract
Caffeic acid phenyl ester (CAPE) is a potent anti-inflammatory agent and it can eliminate the free radicals. This study aimed to investigate the radioprotective effects of CAPE on X-ray irradiation induced intestinal injury in rats. Rats were intragastrically administered with 10 μmol/kg/d CAPE for 7 consecutive days before exposing them to a single dose of X-ray irradiation (9Gy) to abdomen. Rats were sacrificed 72 h after exposure to radiation. We found that pretreatment with CAPE effectively attenuated intestinal pathology changes, apoptosis, oxidative stress, bacterial translocation, the content of nitric oxide and myeloperoxidase as well as the concentration of plasma tumor necrosis factor-α. Pretreatment with CAPE also reversed the activation of p38MAPK and the increased expression of intercellular cell adhesion molecule-1 induced by radiation in intestinal mucosa. Taken together, these results suggest that pretreatment with CAPE could be a promising candidate for treating radiation-induced intestinal injury.
Collapse
Affiliation(s)
- Liu-Gen Jin
- Department of Surgery, The Second Affiliated Hospital of Soochow University, 1055 Sanxiang Road, 215004 Suzhou, China
| | - Jian-Jun Chu
- Department of Oncology, The Affiliated Hospital of Jiangnan University, 200 Huihe Road, 214122 Wuxi, China
| | - Qing-Feng Pang
- Wuxi Medical School, Jiangnan University, 1800 Lihu Road, 214122 Wuxi, China
| | - Fu-Zheng Zhang
- Department of Oncology, The Affiliated Hospital of Jiangnan University, 200 Huihe Road, 214122 Wuxi, China
| | - Gang Wu
- Department of Oncology, The Affiliated Hospital of Jiangnan University, 200 Huihe Road, 214122 Wuxi, China
| | - Le-Yuan Zhou
- Department of Oncology, The Affiliated Hospital of Jiangnan University, 200 Huihe Road, 214122 Wuxi, China
| | - Xiao-Jun Zhang
- Department of Oncology, The Affiliated Hospital of Jiangnan University, 200 Huihe Road, 214122 Wuxi, China
| | - Chun-Gen Xing
- Department of Surgery, The Second Affiliated Hospital of Soochow University, 1055 Sanxiang Road, 215004 Suzhou, China.
| |
Collapse
|
3
|
Zarate N, Wang XY, White EJ, Boreham D, Rangachari PK, Huizinga JD. Low doses of ionizing radiation can prevent radiation-induced colonic epithelial hyporesponsiveness to muscarinic agonists. Int J Radiat Biol 2009; 82:887-98. [PMID: 17178629 DOI: 10.1080/09553000600969820] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE Colonic epithelium hyporesponsiveness to different secretagogues occurs after exposure to ionizing radiation, increasing susceptibility to bacterial translocation and intraluminal toxins. Growing evidence suggests that the biological effects of radiation might be hormetic in nature. We investigated if exposure to low doses of ionizing radiation (LDR) can prevent colon hyposecretion due to subsequent larger doses. METHODS Rats were exposed to LDR (0.05 Gy) 24 h prior to 6 Gy, high dose radiation (HDR). The cyclic adenosine monophosphate (cAMP)-mediated pathway was explored using forskolin (FSK) and the intracellular Ca2+-mediated pathway through cholinergic stimulation. Changes in the colonic epithelium at the ultrastructural level were also explored. RESULTS Maximal short circuit current (Isc) response to carbachol was significantly reduced in the group exposed to 6 Gy HDR and this was completely prevented by prior exposure to LDR. Responses to both FSK and electrical field stimulation (EFS) were significantly reduced after HDR but they were not prevented by prior adaption of LDR. Hyposecretion was not prevented by the inducible nitric oxide synthase (iNOS) inhibitor L-N6-(l-iminoethyl)lysine (L-NIL) ruling out a role for iNOS-derived nitric oxide (NO) in the colonic hyposecretion associated with whole body radiation. Prior exposure to LDR diminished the deleterious effect of full HDR on the ultrastructure of colonic epithelium as colonocytes vacuolization, microvilli lost and separation between neighboring cells were less evident. CONCLUSIONS Previous exposure to LDR can prevent intracellular Ca2+-mediated colonic hyposecretion associated with exposure to HDR but fails to modify cAMP-mediated hyposecretion. Morphological damage at the ultrastructural level is less evident after prior LDR.
Collapse
Affiliation(s)
- N Zarate
- Intestinal Disease Research Program, Health Science Center, McMaster University, hamilton, Ontario, Canada.
| | | | | | | | | | | |
Collapse
|