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Chrétien NM, Zenab Linda FN, Brice Junior NN, Marcelle Olga FY, Vanessa Mba MM, Stephanie Flore DN, Yacine Karelle MK, Elvira NA, Marius M, Gilbert A. Anti-inflammatory, anti-oxidant and anti-ulcer activities of aqueous lyophilizate of Markhamia lutea (Bignoniaceae). JOURNAL OF COMPLEMENTARY & INTEGRATIVE MEDICINE 2024; 21:248-257. [PMID: 38721816 DOI: 10.1515/jcim-2024-0059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 04/10/2024] [Indexed: 06/27/2024]
Abstract
OBJECTIVES This work was carried out with a view to determining the antioxidant, anti-inflammatory and anti-ulcer properties of the aqueous lyophilized extract of Markhamia lutea. METHODS In vitro proteinases inhibition, albumin denaturation, hemolysis of red blood cells by heat, inhibition of the proton pump H+/K+ATPase, FRAP (Ferric reducing antioxidant power) and DPPH (1,1-diphenyl-2-picrylhydrazyl) assays were performed. In vivo, cold water immersion-induced ulceration and methylene blue-induced ulceration was used to determine the anti-ulcer properties of the lyophilizate (100, 200 and 300 mg/kg). RESULTS In vitro, the lyophilizate (400 μg/mL) significantly inhibited protein denaturation (66.65 %), hemolysis of red blood cells (56.54 %), proteinase activity (69.22 %); then the IC50 was 26.31 μg/mL on proton pump activity. It has also developed a strong ferric reducing antioxidant power (EC50=52.96 mmol FeSO4/g) as well as free radicals scavenging activity (EC50=22.38 μg/mL). In vivo, the aqueous lyophilizate (200 and 300 mg/kg) protected the gastric mucosa (70.68 and 79.00 % protection respectively) and reduced (p<0.05) acetylcholine, calcium and corticosterone concentrations. A decrease in malondialdehyde level, an increased glutathione level and an increased in catalase and SOD activities were recorded. In the methylene blue test, it significantly increased gastric fluid pH, while reducing gastric volume and improving hematological parameters in ulcer animals. In addition, the histological sections show that the aqueous lyophilizate of M. lutea protected the gastric mucosa from the deleterious effects of stress. CONCLUSIONS The aqueous lyophilizate of M. lutea has anti-ulcer properties thanks to its anti-inflammatory, antioxidant and anti-secretory properties.
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Affiliation(s)
- Noungoua Mbeugangkeng Chrétien
- Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, 107819 University of Dschang , Douala, Cameroon
| | - Fagni Njoya Zenab Linda
- Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, 107819 University of Dschang , Douala, Cameroon
| | - Nzeumo Nziid Brice Junior
- Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, 107819 University of Dschang , Douala, Cameroon
| | - Feigni Youyi Marcelle Olga
- Laboratory of Biology and Physiology of Animal Organisms, Department of Biology of Animal Organisms, Faculty of Science, The University of Douala Cameroon, Douala, Cameroon
| | - Matah Marthe Vanessa Mba
- Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, 107819 University of Dschang , Douala, Cameroon
| | | | - Madjo Kouam Yacine Karelle
- Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, 107819 University of Dschang , Douala, Cameroon
| | - Ngoufack Azanze Elvira
- Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, 107819 University of Dschang , Douala, Cameroon
| | - Mbiantcha Marius
- Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, 107819 University of Dschang , Douala, Cameroon
| | - Ateufack Gilbert
- Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, 107819 University of Dschang , Douala, Cameroon
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Noor S, Mohammad T, Ashraf GM, Farhat J, Bilgrami AL, Eapen MS, Sohal SS, Yadav DK, Hassan MI. Mechanistic insights into the role of serum-glucocorticoid kinase 1 in diabetic nephropathy: A systematic review. Int J Biol Macromol 2021; 193:562-573. [PMID: 34715204 DOI: 10.1016/j.ijbiomac.2021.10.165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 12/13/2022]
Abstract
Aberrant expression of serum-glucocorticoid kinase 1 (SGK1) contributes to the pathogenesis of multiple disorders, including diabetes, hypertension, obesity, fibrosis, and metabolic syndrome. SGK1 variant is expressed in the presence of insulin and several growth factors, eventually modulating various ion channels, carrier proteins, and transcription factors. SGK1 also regulates the enzymatic activity of Na+ K+ ATPase, glycogen synthase kinase-3, ubiquitin ligase Nedd4-2, and phosphomannose mutase impacting cell cycle regulation, neuroexcitation, and apoptosis. Ample evidence supports the crucial role of aberrant SGK1 expression in hyperglycemia-mediated secondary organ damage. Diabetic nephropathy (DN), a dreadful microvascular complication of diabetes, is the leading cause of end-stage renal failures with high morbidity and mortality rate. The complex pathogenesis of DN encompasses several influencing factors, including transcriptional factors, inflammatory markers, cytokines, epigenetic modulators, and abnormal enzymatic activities. SGK1 plays a pivotal role by controlling various physiological functions associated with the occurrence and progression of DN; therefore, targeting SGK1 may favorably influence the clinical outcome in patients with DN. This review aimed to provide mechanistic insights into SGK1 regulated DN pathogenesis and summarize the evidence supporting the therapeutic potential of SGK1 inhibition and its consequences on human health.
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Affiliation(s)
- Saba Noor
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Taj Mohammad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Gulam M Ashraf
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia; Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Joviana Farhat
- College of Pharmacy, Al Ain University, Abu Dhabi 112612, United Arab Emirates
| | - Anwar L Bilgrami
- Deanship of Scientific Research, King Abdulaziz University, Jeddah, Saudi Arabia; Department of Entomology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Mathew Suji Eapen
- Respiratory Translational Research Group, Department of Laboratory Medicine, School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, TAS, Australia
| | - Sukhwinder Singh Sohal
- Respiratory Translational Research Group, Department of Laboratory Medicine, School of Health Sciences, College of Health and Medicine, University of Tasmania, Launceston, TAS, Australia
| | - Dharmendra Kumar Yadav
- College of Pharmacy, Gachon University of Medicine and Science, Hambakmoeiro, Yeonsu-gu, Incheon City 21924, South Korea.
| | - Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
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Engevik AC, Kaji I, Goldenring JR. The Physiology of the Gastric Parietal Cell. Physiol Rev 2020; 100:573-602. [PMID: 31670611 PMCID: PMC7327232 DOI: 10.1152/physrev.00016.2019] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 10/10/2019] [Accepted: 10/13/2019] [Indexed: 12/11/2022] Open
Abstract
Parietal cells are responsible for gastric acid secretion, which aids in the digestion of food, absorption of minerals, and control of harmful bacteria. However, a fine balance of activators and inhibitors of parietal cell-mediated acid secretion is required to ensure proper digestion of food, while preventing damage to the gastric and duodenal mucosa. As a result, parietal cell secretion is highly regulated through numerous mechanisms including the vagus nerve, gastrin, histamine, ghrelin, somatostatin, glucagon-like peptide 1, and other agonists and antagonists. The tight regulation of parietal cells ensures the proper secretion of HCl. The H+-K+-ATPase enzyme expressed in parietal cells regulates the exchange of cytoplasmic H+ for extracellular K+. The H+ secreted into the gastric lumen by the H+-K+-ATPase combines with luminal Cl- to form gastric acid, HCl. Inhibition of the H+-K+-ATPase is the most efficacious method of preventing harmful gastric acid secretion. Proton pump inhibitors and potassium competitive acid blockers are widely used therapeutically to inhibit acid secretion. Stimulated delivery of the H+-K+-ATPase to the parietal cell apical surface requires the fusion of intracellular tubulovesicles with the overlying secretory canaliculus, a process that represents the most prominent example of apical membrane recycling. In addition to their unique ability to secrete gastric acid, parietal cells also play an important role in gastric mucosal homeostasis through the secretion of multiple growth factor molecules. The gastric parietal cell therefore plays multiple roles in gastric secretion and protection as well as coordination of physiological repair.
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Affiliation(s)
- Amy C Engevik
- Departments of Surgery and of Cell and Developmental Biology and the Epithelial Biology Center, Vanderbilt University School of Medicine, Vanderbilt University Medical Center and the Nashville VA Medical Center, Nashville, Tennessee
| | - Izumi Kaji
- Departments of Surgery and of Cell and Developmental Biology and the Epithelial Biology Center, Vanderbilt University School of Medicine, Vanderbilt University Medical Center and the Nashville VA Medical Center, Nashville, Tennessee
| | - James R Goldenring
- Departments of Surgery and of Cell and Developmental Biology and the Epithelial Biology Center, Vanderbilt University School of Medicine, Vanderbilt University Medical Center and the Nashville VA Medical Center, Nashville, Tennessee
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Alanyl-glutamine Heals Indomethacin-induced Gastric Ulceration in Rats Via Antisecretory and Anti-apoptotic Mechanisms. J Pediatr Gastroenterol Nutr 2019; 69:710-718. [PMID: 31764439 DOI: 10.1097/mpg.0000000000002474] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES Alanylglutamine (AG) is a dipeptide that fuels enterocytes and has a coadjuvant role during gut healing. The current study aimed to investigate the potential ulcer-healing effect of AG in indomethacin-induced gastropathy. METHODS Animals (n = 10 rats/group) were randomly allocated into 5 groups. Gastric ulcerated rats were administered AG, AG + dexamethasone, or pantoprazole after indomethacin exposure. RESULTS Comparable to pantoprazole, AG inhibited H-KATPase pump, and elevated the pH of gastric juice. Moreover, the dipeptide increased the serum/mucosal contents of glucagon-like peptide-1 (GLP-1), pS473-Akt, and cyclin-D1. On the contrary, AG abated serum tumor necrosis factor-α and gastric mucosal content of pS45-β catenin, pS9-GSK3β, pS133-CREB, pS536-NF-κB, H2O2, claudin-1, and caspase-3. The administration of dexamethasone before AG hampered its effect on almost all the measured parameters. CONCLUSIONS AG confers its antiulcerogenic/antisecretory potentials by repressing the proton pump to increase the gastric juice pH via boosting p-CREB, p-Akt, p-GSK-3β, and GLP-1. Also, it inhibits apoptosis through suppressing nuclear factor-kappa B/tumor necrosis factor-α/H2O2/claudin-1 cue. This trajectory contributes to loosen the tight junction priming AG-mediated GLP-1/β-catenin/cyclin-D1 that results in pronounced increase in gastric mucosa proliferation. Therefore, the crosstalk between multiple pathways orchestrates the action of AG against gastric ulceration.
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Hynes D, Harvey BJ. Dexamethasone reduces airway epithelial Cl - secretion by rapid non-genomic inhibition of KCNQ1, KCNN4 and KATP K + channels. Steroids 2019; 151:108459. [PMID: 31330137 DOI: 10.1016/j.steroids.2019.108459] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/05/2019] [Accepted: 07/07/2019] [Indexed: 11/26/2022]
Abstract
Basolateral membrane K+ channels play a key role in basal and agonist stimulated Cl- transport across airway epithelial cells by generating a favourable electrical driving force for Cl- efflux. The K+ channel sub-types and molecular mechanisms of regulation by hormones and secretagoues are still poorly understood. Here we have identified the type of K+ channels involved in cAMP and Ca2+ stimulated Cl- secretion and uncovered a novel anti-secretory effect of dexamethasone mediated by inhibition of basolateral membrane K+ channels in a human airway cell model of 16HBE14o- cells commonly used for ion transport studies. Dexamethasone produced a rapid inhibition of transepithelial chloride ion secretion under steady state conditions and after stimulation with cAMP agonist (forskolin) or a Ca2+ mobilizing agonist (ATP). Our results show three different types of K+ channels are targeted by dexamethasone to reduce airway secretion, namely Ca2+-activated secretion via KCNN4 (KCa3.1) channels and cAMP-activated secretion via KCNQ1 (Kv7.1) and KATP (Kir6.1,6.2) channels. The down-regulation of KCNN4 and KCNQ1 channel activities by dexamethasone involves rapid non-genomic activation of PKCα and PKA signalling pathways, respectively. Dexamethasone signal transduction for PKC and PKA activation was demonstrated to occur through a rapid non-genomic pathway that did not implicate the classical nuclear receptors for glucocorticoids or mineralocorticoids but occurred via a novel signalling cascade involving sequentially a Gi-protein coupled receptor, PKC, adenylyl cyclase Type IV, cAMP, PKA and ERK1/2 activation. The rapid, non-genomic, effects of dexamethasone on airway epithelial ion transport and cell signalling introduces a new paradigm for glucocorticoid actions in lung epithelia which may serve to augment the anti-inflammatory activity of the steroid and enhance its therapeutic potential in treating airway hypersecretion in asthma and COPD.
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Affiliation(s)
- Darina Hynes
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland
| | - Brian J Harvey
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland; Centro di Estudios Cientificos CECs, Valdivia, Chile.
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Neonatal- maternal separation primes zymogenic cells in the rat gastric mucosa through glucocorticoid receptor activity. Sci Rep 2018; 8:9823. [PMID: 29959361 PMCID: PMC6026145 DOI: 10.1038/s41598-018-28223-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/19/2018] [Indexed: 12/21/2022] Open
Abstract
Neonatal- Maternal Separation (NMS) deprives mammals from breastfeeding and maternal care, influencing growth during suckling- weaning transition. In the gastric mucosa, Mist1 (encoded by Bhlha15 gene) and moesin organize the secretory apparatus for pepsinogen C in zymogenic cells. Our current hypothesis was that NMS would change corticosterone activity through receptors (GR), which would modify molecules involved in zymogenic cell differentiation in rats. We found that NMS increased corticosterone levels from 18 days onwards, as GR decreased in the gastric mucosa. However, as nuclear GR was detected, we investigated receptor binding to responsive elements (GRE) and observed an augment in NMS groups. Next, we demonstrated that NMS increased zymogenic population (18 and and 30 days), and targeted Mist1 and moesin. Finally, we searched for evolutionarily conserved sequences that contained GRE in genes involved in pepsinogen C secretion, and found that the genomic regions of Bhlha15 and PgC contained sites highly likely to be responsive to glucocorticoids. We suggest that NMS triggers GR- GRE to enhance the expression and to prime genes that organize cellular architecture in zymogenic population for PgC function. As pepsinogen C- pepsin is essential for digestion, disturbance of parenting through NMS might alter functions of gastric mucosa in a permanent manner.
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Zulian JG, Hosoya LYM, Figueiredo PM, Ogias D, Osaki LH, Gama P. Corticosterone activity during early weaning reprograms molecular markers in rat gastric secretory cells. Sci Rep 2017; 7:45867. [PMID: 28361902 PMCID: PMC5374460 DOI: 10.1038/srep45867] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/03/2017] [Indexed: 12/19/2022] Open
Abstract
Gastric epithelial cells differentiate throughout the third postnatal week in rats, and become completely functional by weaning time. When suckling is interrupted by early weaning (EW), cell proliferation and differentiation change in the gastric mucosa, and regulatory mechanisms might involve corticosterone activity. Here we used EW and RU486 (glucocorticoid receptor antagonist) to investigate the roles of corticosterone on differentiation of mucous neck (MNC) and zymogenic cells (ZC) in rats, and to evaluate whether effects persisted in young adults. MNC give rise to ZC, and mucin 6, Mist1, pepsinogen a5 and pepsinogen C are produced to characterize these cells. We found that in pups, EW augmented the expression of mucins, Mist1 and pepsinogen C at mRNA and protein levels, and it changed the number of MNC and ZC. Corticosterone regulated pepsinogen C expression, and MNC and ZC distributions. Further, the changes on MNC population and pepsinogen C were maintained until early- adult life. Therefore, by using EW as a model for altered corticosterone activity in rats, we demonstrated that the differentiation of secretory epithelial cells is sensitive to the type of nutrient in the lumen. Moreover, this environmental perception activates corticosterone to change maturation and reprogram cellular functions in adulthood.
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Affiliation(s)
- Juliana Guimarães Zulian
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | | | - Priscila Moreira Figueiredo
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Daniela Ogias
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Luciana Harumi Osaki
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Patricia Gama
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
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Reichardt SD, Weinhage T, Rotte A, Föller M, Oppermann M, Lühder F, Tuckermann JP, Lang F, van den Brandt J, Reichardt HM. Glucocorticoids induce gastroparesis in mice through depletion of l-arginine. Endocrinology 2014; 155:3899-908. [PMID: 25057793 DOI: 10.1210/en.2014-1246] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glucocorticoids (GCs) constitute a highly pleiotropic class of drugs predominantly employed in the treatment of inflammatory diseases. In our search for new mechanisms of action, we identified a hitherto unknown effect of GCs in the gastrointestinal tract. We found that oral administration of dexamethasone (Dex) to mice caused an enlargement of the stomach due to the induction of gastroparesis and that this effect was abolished in GR(dim) mice carrying the A458T mutation in the GC receptor (GR). Gastroparesis was unrelated to the enhanced gastric acid secretion observed after Dex treatment, although both effects were mediated by the same molecular mechanism of the GR. Using conditional GR-knockout mice, we could further rule out that GC effects on enterocytes or myeloid cells were involved in the induction of gastroparesis. In contrast, we found that Dex upregulated arginase 2 (Arg2) in the stomach both at the mRNA and protein level. This suggests that GC treatment leads to a depletion of l-arginine thereby impeding the production of nitric oxide (NO), which is required for gastric motility. We tested this hypothesis by supplementing the drinking water of the mice with exogenous l-arginine to compensate for the presumed shortage of this major substrate of NO synthases. Importantly, this measure completely prevented both the enlargement of the stomach and the induction of gastroparesis after Dex treatment. Our findings raise considerations of combining orally applied GCs with l-arginine to improve tolerability of GC treatment and provide a possible explanation for the antiemetic effects of GCs widely exploited in chemotherapy.
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Affiliation(s)
- Sybille D Reichardt
- Institute for Cellular and Molecular Immunology (S.D.R., T.W., M.O., J.v.d.B., H.M.R.) and Department of Neuroimmunology (F.L.), Institute for Multiple Sclerosis Research, The Hertie Foundation and MPI for Experimental Medicine, University of Göttingen Medical School, 37073 Göttingen, Germany; Institute of Physiology (A.R., M.F., F.L.), University of Tübingen, 72076 Tübingen, Germany; and Institute of General Zoology and Endocrinology (J.P.T.), University of Ulm, 89081 Ulm, Germany
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Andersen MN, Krzystanek K, Petersen F, Bomholtz SH, Olesen SP, Abriel H, Jespersen T, Rasmussen HB. A phosphoinositide 3-kinase (PI3K)-serum- and glucocorticoid-inducible kinase 1 (SGK1) pathway promotes Kv7.1 channel surface expression by inhibiting Nedd4-2 protein. J Biol Chem 2013; 288:36841-54. [PMID: 24214981 DOI: 10.1074/jbc.m113.525931] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Epithelial cell polarization involves several kinase signaling cascades that eventually divide the surface membrane into an apical and a basolateral part. One kinase, which is activated during the polarization process, is phosphoinositide 3-kinase (PI3K). In MDCK cells, the basolateral potassium channel Kv7.1 requires PI3K activity for surface-expression during the polarization process. Here, we demonstrate that Kv7.1 surface expression requires tonic PI3K activity as PI3K inhibition triggers endocytosis of these channels in polarized MDCK. Pharmacological inhibition of SGK1 gave similar results as PI3K inhibition, whereas overexpression of constitutively active SGK1 overruled it, suggesting that SGK1 is the primary downstream target of PI3K in this process. Furthermore, knockdown of the ubiquitin ligase Nedd4-2 overruled PI3K inhibition, whereas a Nedd4-2 interaction-deficient Kv7.1 mutant was resistant to both PI3K and SGK1 inhibition. Altogether, these data suggest that a PI3K-SGK1 pathway stabilizes Kv7.1 surface expression by inhibiting Nedd4-2-dependent endocytosis and thereby demonstrates that Nedd4-2 is a key regulator of Kv7.1 localization and turnover in epithelial cells.
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Affiliation(s)
- Martin Nybo Andersen
- From The Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark and
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Hou G, Tang M, Yan L, Wang M. Changes of ultrastructure and downregulation of heat shock protein 70 and fibroblast growth factor 2 in gastric mucosa of rats with depressive-like behaviour. Acta Neuropsychiatr 2012; 24:160-5. [PMID: 26953009 DOI: 10.1111/j.1601-5215.2011.00599.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To understand the underlying mechanism of gastric symptoms in patients with depressive disorder. METHODS This study tested in the rat depression model evoked with chronic mild stress whether the microstructure gastric mucosa is injured using scanning electronic microscopy and transmission electronic microscopy (TEM). In addition, the expression of heat shock protein 70 (HSP70) and fibroblast growth factor 2 (FGF2) proteins in the gastric mucosa were measured by Western blotting. RESULTS We found that the gastric epithelial cells were ruptured and the gastric pits were widened in rats with depression. The amount of mucous granules was also reduced in the surface mucous cells. Moreover, parietal cells became active, and the secretory canaliculi were magnified. Expression of HSP70 and FGF2 was reduced in the gastric mucosa. CONCLUSIONS These findings suggested that gastric symptoms in rats with depressive-like behaviour were caused by the injury of the gastric mucosa, AQ1 and HSP70 and FGF2 may be key molecules in the pathogenesis.
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Affiliation(s)
- Gonglin Hou
- Department of psychology, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Mingming Tang
- Department of psychology, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Linlin Yan
- Department of psychology, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Mingming Wang
- Department of psychology, Zhejiang Sci-Tech University, Hangzhou 310018, China
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Serum- and glucocorticoid-inducible kinase 1 in the regulation of renal and extrarenal potassium transport. Clin Exp Nephrol 2011; 16:73-80. [DOI: 10.1007/s10157-011-0488-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 04/08/2010] [Indexed: 01/24/2023]
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Beck IM, De Bosscher K, Haegeman G. Glucocorticoid receptor mutants: man-made tools for functional research. Trends Endocrinol Metab 2011; 22:295-310. [PMID: 21549614 DOI: 10.1016/j.tem.2011.03.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 03/20/2011] [Accepted: 03/31/2011] [Indexed: 12/18/2022]
Abstract
The glucocorticoid receptor (GR) is a ligand-dependent transcription factor that can bind to glucocorticoids (GCs). Upon ligand binding, GR sheds its cytoplasmic chaperoning complex and translocates to the nucleus, where it can act as a ligand-dependent transcription factor, transactivating or transrepressing specific gene promoters. Often, GR interacts with specific cofactors to implement a variety of gene promoter effects. GR activity and function is further modulated by post-translational modifications. To assess the diverse aspects of GR mechanisms of activation and gene regulation, researchers continue to use a range of artificial GR mutants. In this review we analyze the characteristics of GR mutants with the aim of assisting the design and interpretation of GR mutant-based experiments.
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Affiliation(s)
- Ilse M Beck
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Department of Physiology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
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Rexhepaj R, Alesutan I, Gu S, Pelzl L, Eichenmüller M, Pathare G, Föller M, Kuhl D, Lang F. SGK1-dependent stimulation of intestinal SGLT1 activity by vitamin D. Pflugers Arch 2011; 462:489-94. [PMID: 21735060 DOI: 10.1007/s00424-011-0987-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 06/10/2011] [Accepted: 06/11/2011] [Indexed: 12/26/2022]
Abstract
The serum- and glucocorticoid-inducible kinase SGK1 has previously been shown to mediate the glucocorticoid-dependent stimulation of several intestinal transport systems including the electrogenic glucose transporter SGLT1. In squamous carcinoma cells, SGK1 expression is stimulated by 1,25(OH)₂D₃, the biologically active metabolite of vitamin D. The present study explored whether vitamin D influences the intestinal SGLT1 activity. Jejunal SGLT1 activity was determined by Ussing chamber experiments. Under a normal diet, the electrogenic glucose transport was similar in SGK1 knockout (sgk1 ( -/- )) and wild type mice (sgk1 ( +/+ )). Following a vitamin D-rich diet (14 days 10,000 I.U. vitamin D), the SGK1 transcript levels as well as the SGLT1 protein abundance were increased in sgk1(+/+) mice. Moreover, SGLT1 activity was increased in sgk1(+/+) mice but not in sgk1(-/-) mice following a vitamin D-rich diet. Furthermore, an oral glucose load was followed by an increase in the plasma glucose concentration to significantly higher values in sgk1(+/+) mice treated with a vitamin D-rich diet than in untreated sgk1(+/+) mice. In conclusion, vitamin D treatment upregulates the expression of SGK1, which in turn enhances SGLT1 activity.
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Affiliation(s)
- Rexhep Rexhepaj
- Department of Physiology, University of Tübingen, Tübingen, Germany
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Pasham V, Rotte A, Bhandaru M, Eichenmüller M, Bobbala D, Yang W, Pearce D, Lang F, Pearce D, Lang F. Regulation of gastric acid secretion by the serum and glucocorticoid inducible kinase isoform SGK3. J Gastroenterol 2011; 46:305-17. [PMID: 21113728 PMCID: PMC6049078 DOI: 10.1007/s00535-010-0348-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 10/26/2010] [Indexed: 02/04/2023]
Abstract
BACKGROUND The serum and glucocorticoid inducible kinase isoform SGK3 is ubiquitously expressed and has been shown to participate in the regulation of cell survival and transport. Similar to SGK1 and protein kinase B (PKB/Akt) isoforms, SGK3 may phosphorylate glycogen synthase kinase (GSK) 3α,β, which has recently been shown to participate in the regulation of basal gastric acid secretion. The present study thus explored the role of SGK3 in the regulation of gastric acid secretion. METHODS Experiments were performed in isolated glands from gene-targeted mice lacking functional SGK3 (sgk3-/-) or from their wild-type littermates (sgk3+/+). Utilizing 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, acetoxymethyl ester (BCECF) fluorescence, gastric acid secretion was determined from Na(+)-independent pH recovery (∆pH/min) following an ammonium pulse, which reflects H+/K+ adenosine triphosphatase (ATP) ase activity. RESULTS Cytosolic pH in isolated gastric glands was similar in sgk3-/- and sgk3+/+ mice. ∆pH/min was, however, significantly larger in sgk3-/- than in sgk3+/+ mice. In both genotypes, ∆pH/min was virtually abolished in the presence of the H(+)/K(+) ATPase inhibitor omeprazole (100 μM) and SCH28080 (500 nM). Increase of extracellular K+ concentrations to 35 mM (replacing Na+/NMDG) or treatment with 5 μM forskolin increased ∆pH/min in sgk3+/+ mice to a larger extent than in sgk3-/- mice and abrogated the differences between genotypes. The protein kinase A inhibitor H89 (150 nM) decreased ∆pH/min to similarly low values in both genotypes. CONCLUSIONS SGK3 suppresses gastric acid secretion, an effect presumably mediated by the stimulation of protein kinase A with the subsequent activation of K+ channels.
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Affiliation(s)
| | - Anand Rotte
- Department of Physiology, University of Tübingen, Germany
| | | | | | | | - Wenting Yang
- Department of Physiology, University of Tübingen, Germany
| | - David Pearce
- Department of Medicine (Nephrology), University of California, San Francisco, CA 94122, USA
| | - Florian Lang
- Department of Physiology, University of Tübingen, Germany
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Regulation of basal gastric acid secretion by the glycogen synthase kinase GSK3. J Gastroenterol 2010; 45:1022-32. [PMID: 20552232 DOI: 10.1007/s00535-010-0260-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 05/05/2010] [Indexed: 02/04/2023]
Abstract
BACKGROUND According to previous observations, basal gastric acid secretion is downregulated by phosphoinositol-3-(PI3)-kinase, phosphoinositide-dependent kinase (PDK1), and protein kinase B (PKBβ/Akt2) signaling. PKB/Akt phosphorylates glycogen synthase kinase GSK3. The present study explored whether PKB/Akt-dependent GSK3-phosphorylation modifies gastric acid secretion. METHODS Utilizing 2',7'-bis-(carboxyethyl)-5(6')-carboxyfluorescein (BCECF)-fluorescence, basal gastric acid secretion was determined from Na(+)-independent pH recovery (∆pH/min) following an ammonium pulse, which reflects H(+)/K(+)-ATPase activity. Experiments were performed in gastric glands from gene-targeted mice (gsk3 ( KI )) with PKB/serum and glucocorticoid-inducible kinase (SGK)-insensitive GSKα,β, in which the serines within the PKB/SGK phosphorylation site were replaced by alanine (GSK3α(21A/21A), GSK3β(9A/9A)). RESULTS The cytosolic pH in isolated gastric glands was similar in gsk3 ( KI ) and their wild-type littermates (gsk3 ( WT )). However, ∆pH/min was significantly larger in gsk3 ( KI ) than in gsk3 ( WT ) mice and ∆pH/min was virtually abolished by the H(+)/K(+)-ATPase inhibitor omeprazole (100 μM) in gastric glands from both gsk3 ( KI ) and gsk3 ( WT ). Plasma gastrin levels were lower in gsk3 ( KI ) than in gsk3 ( WT ). Both, an increase of extracellular K(+) concentration to 35 mM [replacing Na(+)/N-methyl-D: -glucamine (NMDG)] and treatment with forskolin (5 μM), significantly increased ∆pH/min to virtually the same value in both genotypes. The protein kinase A (PKA) inhibitor H89 (150 nM) and the H(2)-receptor antagonist ranitidine (100 μM) decreased ∆pH/min in gsk3 ( KI ) but not gsk3 ( WT ) and again abrogated the differences between the genotypes. The protein abundance of phosphorylated but not of total PKA was significantly larger in gsk3 ( KI ) than in gsk3 ( WT ). CONCLUSIONS Basal gastric acid secretion is enhanced by the disruption of PKB/SGK-dependent phosphorylation and the inhibition of GSK3. Thus, the inhibition of GSK3 participates in the signaling of PI3-kinase-dependent downregulation of basal gastric acid secretion.
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Rotte A, Pasham V, Bhandaru M, Eichenmüller M, Yang W, Qadri SM, Kempe DS, Puchchakayala G, Pearce D, Birnbaum MJ, Lang F. Regulation of gastric acid secretion by PKB/Akt2. Cell Physiol Biochem 2010; 25:695-704. [PMID: 20511715 DOI: 10.1159/000315089] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2010] [Indexed: 12/16/2022] Open
Abstract
Pharmacological inhibition of phosphoinositol 3 kinase (PI3K) and partial deficiency of phosphoinositide dependent kinase PDK1 have previously been shown to enhance basal gastric acid secretion. PI3K/PDK1 dependent signaling involves activation of protein kinase B/Akt, which may thus be similarly involved in the regulation of gastric acid secretion. To test that hypothesis, gastric acid secretion was determined in isolated glands from gene targeted mice lacking functional Akt2 (akt2(-/-)) or from their wild type littermates (akt2(+/+)). According to BCECF-fluorescence cytosolic pH in isolated gastric glands was similar in akt2(-/-) and akt2(+/+) mice. Na(+)-independent pH recovery (DeltapH/min) following an ammonium pulse, a measure of H(+)/K(+) ATPase activity, was, however, significantly faster in akt2(-/-) than in akt2(+/+) mice. In both genotypes, DeltapH/min was virtually abolished by H(+)/K(+) ATPase inhibitor omeprazole (100 muM). Increase of extracellular K(+) concentrations to 35 mM (replacing Na(+)) increased DeltapH/min to a significantly larger extent in akt2(+/+) than in akt2(-/-) mice and dissipated the differences between the genotypes. Similarly, treatment with 5 muM forskolin enhanced DeltapH/min significantly only in akt2(+/+) mice and abolished the differences between the genotypes. Conversely, protein kinase A inhibitor H89 (50 nM) decreased DeltapH/min to similarly low values in both genotypes. In conclusion, Akt2 suppresses gastric acid secretion and contributes to or even accounts for the inhibition of gastric acid secretion by PI3K.
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Affiliation(s)
- Anand Rotte
- Department of Physiology, University of Tübingen, D-72076 Tübingen, Germany
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Sopjani M, Kunert A, Czarkowski K, Klaus F, Laufer J, Föller M, Lang F. Regulation of the Ca2+ Channel TRPV6 by the Kinases SGK1, PKB/Akt, and PIKfyve. J Membr Biol 2009; 233:35-41. [DOI: 10.1007/s00232-009-9222-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 12/02/2009] [Indexed: 12/29/2022]
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Abstract
Compelling evidence is accumulating indicating a pathophysiological role of the serum-and-glucocorticoid-inducible-kinase-1 (SGK1) in the development and complications of diabetes. SGK1 is ubiquitously expressed with exquisitely high transcriptional volatility. Stimulators of SGK1 expression include hyperglycemia, cell shrinkage, ischemia, glucocorticoids and mineralocorticoids. SGK1 is activated by insulin and growth factors via PI3K, 3-phosphoinositide dependent kinase PDK1 and mTOR. SGK1 activates ion channels (including ENaC, TRPV5, ROMK, KCNE1/KCNQ1 and CLCKa/Barttin), carriers (including NCC, NKCC, NHE3, SGLT1 and EAAT3), and the Na(+)/K(+)-ATPase. It regulates the activity of several enzymes (e.g., glycogen-synthase-kinase-3, ubiquitin-ligase Nedd4-2, phosphomannose-mutase-2), and transcription factors (e.g., forkhead-transcription-factor FOXO3a, beta-catenin and NF-kappaB). A common SGK1 gene variant ( approximately 3 - 5% prevalence in Caucasians, approximately 10% in Africans) is associated with increased blood pressure, obesity and type 2 diabetes. In patients suffering from type 2 diabetes, SGK1 presumably contributes to fluid retention and hypertension, enhanced coagulation and increased deposition of matrix proteins leading to tissue fibrosis such as diabetic nephropathy. Accordingly, targeting SGK1 may favourably influence occurrence and course of type 2 diabetes.
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Affiliation(s)
- Florian Lang
- Eberhard-Karls-University of Tuebingen, Department of Physiology, Gmelinstrasse 5, Tuebingen 72076, Germany.
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Lang F, Görlach A. Heterocyclic indazole derivatives as SGK1 inhibitors, WO2008138448. Expert Opin Ther Pat 2009; 20:129-35. [DOI: 10.1517/13543770903365209] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Beck IME, Vanden Berghe W, Vermeulen L, Yamamoto KR, Haegeman G, De Bosscher K. Crosstalk in inflammation: the interplay of glucocorticoid receptor-based mechanisms and kinases and phosphatases. Endocr Rev 2009; 30:830-82. [PMID: 19890091 PMCID: PMC2818158 DOI: 10.1210/er.2009-0013] [Citation(s) in RCA: 221] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 08/18/2009] [Indexed: 12/20/2022]
Abstract
Glucocorticoids (GCs) are steroidal ligands for the GC receptor (GR), which can function as a ligand-activated transcription factor. These steroidal ligands and derivatives thereof are the first line of treatment in a vast array of inflammatory diseases. However, due to the general surge of side effects associated with long-term use of GCs and the potential problem of GC resistance in some patients, the scientific world continues to search for a better understanding of the GC-mediated antiinflammatory mechanisms. The reversible phosphomodification of various mediators in the inflammatory process plays a key role in modulating and fine-tuning the sensitivity, longevity, and intensity of the inflammatory response. As such, the antiinflammatory GCs can modulate the activity and/or expression of various kinases and phosphatases, thus affecting the signaling efficacy toward the propagation of proinflammatory gene expression and proinflammatory gene mRNA stability. Conversely, phosphorylation of GR can affect GR ligand- and DNA-binding affinity, mobility, and cofactor recruitment, culminating in altered transactivation and transrepression capabilities of GR, and consequently leading to a modified antiinflammatory potential. Recently, new roles for kinases and phosphatases have been described in GR-based antiinflammatory mechanisms. Moreover, kinase inhibitors have become increasingly important as antiinflammatory tools, not only for research but also for therapeutic purposes. In light of these developments, we aim to illuminate the integrated interplay between GR signaling and its correlating kinases and phosphatases in the context of the clinically important combat of inflammation, giving attention to implications on GC-mediated side effects and therapy resistance.
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Affiliation(s)
- Ilse M E Beck
- Laboratory of Eukaryotic Gene Expression and Signal Transduction, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium
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The physiological impact of the serum and glucocorticoid-inducible kinase SGK1. Curr Opin Nephrol Hypertens 2009; 18:439-48. [PMID: 19584721 DOI: 10.1097/mnh.0b013e32832f125e] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW The role of serum and glucocorticoid-inducible kinase 1 (SGK1) in renal physiology and pathophysiology is reviewed with particular emphasis on recent advances. RECENT FINDINGS The mammalian target of rapamycin complex 2 has been shown to phosphorylate SGK1 at Ser422 (the so-called hydrophobic motif). Ser397 and Ser401 are two additional SGK1-phosphorylation sites required for maximal SGK1 activity. A 5' variant alternate transcript of human Sgk1 has been identified that is widely expressed and shows improved stability, enhanced membrane association, and greater stimulation of epithelial Na+ transport. SGK1 is essential for optimal processing of the epithelial sodium channel and also regulates the expression of the Na+-Cl- cotransporter. With regard to pathophysiology, SGK1 participates in the stimulation of renal tubular glucose transport in diabetes, the renal profibrotic effect of both angiotensin II and aldosterone, and in fetal programing of arterial hypertension. SUMMARY The outlined recent findings advanced our understanding of the molecular regulation of SGK1 as well as the role of the kinase in renal physiology and the pathophysiology of renal disease and hypertension. Future studies using pharmacological inhibitors of SGK1 will reveal the utility of the kinase as a new therapeutic target.
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Rexhepaj R, Rotte A, Kempe DS, Sopjani M, Föller M, Gehring EM, Bhandaru M, Gruner I, Mack AF, Rubio-Aliaga I, Nässl AM, Daniel H, Kuhl D, Lang F. Stimulation of electrogenic intestinal dipeptide transport by the glucocorticoid dexamethasone. Pflugers Arch 2009; 459:191-202. [PMID: 19672619 DOI: 10.1007/s00424-009-0701-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 06/03/2009] [Accepted: 07/11/2009] [Indexed: 01/09/2023]
Abstract
According to recent in vitro experiments, the peptide transporter PepT2 is stimulated by the serum- and glucocorticoid-inducible kinase SGK1. The present study explored the contribution of SGK1 to the regulation of electrogenic intestinal peptide transport. Intestinal PepT1 was expressed in Xenopus oocytes, and peptide transport was determined by dual electrode voltage clamping. Peptide transport in intestinal segments was determined utilizing Ussing chamber. Cytosolic pH (pH( i )) was determined by BCECF fluorescence and Na(+)/H(+) exchanger activity was estimated from Na(+)-dependent pH recovery (pH ( i )) following an ammonium pulse. In PepT1-expressing Xenopus oocytes, coexpression of SGK1 enhanced electrogenic peptide transport. Intestinal transport and pH( i ) of untreated mice were similar in SGK1 knockout mice (sgk1 ( -/- )) and their wild-type littermates (sgk1 ( +/+ )). Glucocorticoid treatment (4 days 10 microg/g body weight (bw)/day dexamethasone) increased peptide transport in sgk1 ( +/+ ) but not in sgk1 (-/-) mice. Irrespective of dexamethasone treatment, luminal peptide (5 mM glycyl-glycine) led to a similar early decrease of pH( i ) in sgk1 (-/-) and sgk1 (+/+) mice, but to a more profound and sustained decline of pH( i ) in sgk1 (-/-) than in sgk1 ( +/+ ) mice. In the presence and absence of glycyl-glycine, pH ( i ) was significantly enhanced by dexamethasone treatment in sgk1 ( +/+ ) mice, an effect significantly blunted in sgk1 ( -/- ) mice. During sustained exposure to glycyl-glycine, pH ( i ) was significantly larger in sgk1 (+/+) mice than in sgk1 (-/-) mice, irrespective of dexamethasone treatment. In conclusion, basal intestinal peptide transport does not require stimulation by SGK1. Glucocorticoid treatment stimulates both Na(+)/H(+) exchanger activity and peptide transport, effects partially dependent on SGK1. Moreover, chronic exposure to glycyl-glycine stimulates Na(+)/H(+) exchanger activity, an effect again involving SGK1.
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Affiliation(s)
- Rexhep Rexhepaj
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
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Abstract
PURPOSE OF REVIEW This review summarizes the past year's literature regarding the regulation and assessment of gastric acid secretion. RECENT FINDINGS Gastric acid secretion is regulated by biologic agents produced and released by enteroendocrine cells and neurons as well as by exogenously administered substances and infection. Too much acid can lead to gastroesophageal reflux disease, peptic ulcer disease, and stress-related erosion/ulcer disease. Too little acid can interfere with the absorption of certain nutrients, predispose to enteric infection, and interfere with the absorption of some medications. Gastrin, histamine, gastrin-releasing peptide, ghrelin, orexin, and glucocorticoids stimulate whereas leptin, glucagon-like peptide 1, and Helicobacter pylori inhibit acid secretion. Helicobacter pylori inhibits the transcriptional activity of HK-ATPase, the proton pump of the parietal cell. SUMMARY A better understanding of the pathways and mechanisms regulating gastric acid secretion should lead to improved management of patients with acid-induced disorders as well as those who secrete too little acid.
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