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Fan W, Tan Q. Application of the steady-state intestinal perfusion system in measuring intestinal fluid absorption and bicarbonate secretion in vivo. Front Physiol 2023; 14:1163888. [PMID: 37497438 PMCID: PMC10366686 DOI: 10.3389/fphys.2023.1163888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 06/26/2023] [Indexed: 07/28/2023] Open
Abstract
Background: The steady-state intestinal perfusion system represents a tool used in measuring intestinal fluid absorption and bicarbonate secretion in vivo; however, detailed procedures and parameters were not elucidated fully. Aim: We focused on the methods of the steady-state intestinal perfusion system comprehensively including the blood pressure, hematocrit, blood gas, and heart rate of mouse. Methods: Anesthetized, tracheally intubated, and artificially ventilated mice were used for this system. The blood pressure, hematocrit, blood gas, heart rate, and rate of fluid absorption and HCO3 - secretion of the small intestine and colon at different time points were evaluated. Results: Blood pressure, hematocrit, blood gas, and heart rate became stable at the 30 min time point after completion of surgery and could be maintained for 2 h. Rates of fluid absorption and bicarbonate secretion were also kept stable during the period of steady state of mice. Rates of fluid absorption and bicarbonate secretion were different among the jejunum, ileum, proximal, and mid-distal colon. Conclusion: The steady-state intestinal perfusion system is a reliable system for measuring intestinal fluid absorption and bicarbonate secretion in vivo.
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Sauer AK, Malijauskaite S, Meleady P, Boeckers TM, McGourty K, Grabrucker AM. Zinc is a key regulator of gastrointestinal development, microbiota composition and inflammation with relevance for autism spectrum disorders. Cell Mol Life Sci 2021; 79:46. [PMID: 34936034 PMCID: PMC11072240 DOI: 10.1007/s00018-021-04052-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/31/2021] [Accepted: 11/18/2021] [Indexed: 12/15/2022]
Abstract
Gastrointestinal (GI) problems and microbiota alterations have been frequently reported in autism spectrum disorders (ASD). In addition, abnormal perinatal trace metal levels have been found in ASD. Accordingly, mice exposed to prenatal zinc deficiency display features of ASD-like behavior. Here, we model GI development using 3D intestinal organoids grown under zinc-restricted conditions. We found significant morphological alterations. Using proteomic approaches, we identified biological processes affected by zinc deficiency that regulate barrier permeability and pro-inflammatory pathways. We confirmed our results in vivo through proteomics studies and investigating GI development in zinc-deficient mice. These show altered GI physiology and pro-inflammatory signaling, resulting in chronic systemic and neuroinflammation, and gut microbiota composition similar to that reported in human ASD cases. Thus, low zinc status during development is sufficient to compromise intestinal barrier integrity and activate pro-inflammatory signaling, resulting in changes in microbiota composition that may aggravate inflammation, altogether mimicking the co-morbidities frequently observed in ASD.
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Affiliation(s)
- Ann Katrin Sauer
- Cellular Neurobiology and Neuro-Nanotechnology Lab, Department of Biological Sciences, University of Limerick, Bernal Institute, Analog Devices Building AD3-018, Castletroy, Limerick, V94PH61, Ireland
- Bernal Institute, University of Limerick, Limerick, Ireland
- Health Research Institute (HRI), University of Limerick, Limerick, Ireland
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Sigita Malijauskaite
- Bernal Institute, University of Limerick, Limerick, Ireland
- Department of Chemical Sciences, University of Limerick, Limerick, Ireland
| | - Paula Meleady
- School of Biotechnology and National Institute for Cellular Biotechnology, Dublin City University, Dublin, Ireland
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- DZNE, Ulm Unit, Ulm, Germany
| | - Kieran McGourty
- Bernal Institute, University of Limerick, Limerick, Ireland
- Health Research Institute (HRI), University of Limerick, Limerick, Ireland
- Department of Chemical Sciences, University of Limerick, Limerick, Ireland
| | - Andreas M Grabrucker
- Cellular Neurobiology and Neuro-Nanotechnology Lab, Department of Biological Sciences, University of Limerick, Bernal Institute, Analog Devices Building AD3-018, Castletroy, Limerick, V94PH61, Ireland.
- Bernal Institute, University of Limerick, Limerick, Ireland.
- Health Research Institute (HRI), University of Limerick, Limerick, Ireland.
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Dobrinskikh E, Lewis L, Brian Doctor R, Okamura K, Lee MG, Altmann C, Faubel S, Kopp JB, Blaine J. Shank2 Regulates Renal Albumin Endocytosis. Physiol Rep 2015; 3:e12510. [PMID: 26333830 PMCID: PMC4600376 DOI: 10.14814/phy2.12510] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 07/22/2015] [Accepted: 07/26/2015] [Indexed: 12/22/2022] Open
Abstract
Albuminuria is a strong and independent predictor of kidney disease progression but the mechanisms of albumin handling by the kidney remain to be fully defined. Previous studies have shown that podocytes endocytose albumin. Here we demonstrate that Shank2, a large scaffolding protein originally identified at the neuronal postsynaptic density, is expressed in podocytes in vivo and in vitro and plays an important role in albumin endocytosis in podocytes. Knockdown of Shank2 in cultured human podocytes decreased albumin uptake, but the decrease was not statistically significant likely due to residual Shank2 still present in the knockdown podocytes. Complete knockout of Shank2 in podocytes significantly diminished albumin uptake in vitro. Shank2 knockout mice develop proteinuria by 8 weeks of age. To examine albumin handling in vivo in wild-type and Shank2 knockout mice we used multiphoton intravital imaging. While FITC-labeled albumin was rapidly seen in the renal tubules of wild-type mice after injection, little albumin was seen in the tubules of Shank2 knockout mice indicating dysregulated renal albumin trafficking in the Shank2 knockouts. We have previously found that caveolin-1 is required for albumin endocytosis in cultured podocytes. Shank2 knockout mice had significantly decreased expression and altered localization of caveolin-1 in podocytes suggesting that disruption of albumin endocytosis in Shank2 knockouts is mediated via caveolin-1. In summary, we have identified Shank2 as another component of the albumin endocytic pathway in podocytes.
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Affiliation(s)
| | - Linda Lewis
- University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | | | - Kayo Okamura
- University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Min Goo Lee
- Department of Pharmacology, Severance Biomedical Science Institute Yonsei University College of Medicine, Seoul, Korea
| | | | - Sarah Faubel
- University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Jeffrey B Kopp
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, Bethesda, Maryland
| | - Judith Blaine
- University of Colorado Anschutz Medical Campus, Aurora, Colorado
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Koeppen K, Coutermarsh BA, Madden DR, Stanton BA. Serum- and glucocorticoid-induced protein kinase 1 (SGK1) increases the cystic fibrosis transmembrane conductance regulator (CFTR) in airway epithelial cells by phosphorylating Shank2E protein. J Biol Chem 2014; 289:17142-50. [PMID: 24811177 DOI: 10.1074/jbc.m114.555599] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The glucocorticoid dexamethasone increases cystic fibrosis transmembrane conductance regulator (CFTR) abundance in human airway epithelial cells by a mechanism that requires serum- and glucocorticoid-induced protein kinase 1 (SGK1) activity. The goal of this study was to determine whether SGK1 increases CFTR abundance by phosphorylating Shank2E, a PDZ domain protein that contains two SGK1 phosphorylation consensus sites. We found that SGK1 phosphorylates Shank2E as well as a peptide containing the first SGK1 consensus motif of Shank2E. The dexamethasone-induced increase in CFTR abundance was diminished by overexpression of a dominant-negative Shank2E in which the SGK1 phosphorylation sites had been mutated. siRNA-mediated reduction of Shank2E also reduced the dexamethasone-induced increase in CFTR abundance. Taken together, these data demonstrate that the glucocorticoid-induced increase in CFTR abundance requires phosphorylation of Shank2E at an SGK1 consensus site.
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Affiliation(s)
- Katja Koeppen
- From the Department of Microbiology and Immunology and
| | | | - Dean R Madden
- Department of Biochemistry, The Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755
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