%0 Journal Article %1 engevik2018myo5b %A Engevik, A. C. %A Kaji, I. %A Engevik, M. A. %A Meyer, A. R. %A Weis, V. G. %A Goldstein, A. %A Hess, M. W. %A Muller, T. %A Koepsell, H. %A Dudeja, P. K. %A Tyska, M. %A Huber, L. A. %A Shub, M. D. %A Ameen, N. %A Goldenring, J. R. %D 2018 %J Gastroenterology %K Animals myOwn %N 6 %P 1883-1897 e10 %R 10.1053/j.gastro.2018.08.025 %T Loss of MYO5B Leads to Reductions in Na(+) Absorption With Maintenance of CFTR-Dependent Cl(-) Secretion in Enterocytes %U https://www.ncbi.nlm.nih.gov/pubmed/30144427 %V 155 %X BACKGROUND & AIMS: Inactivating mutations in MYO5B cause microvillus inclusion disease (MVID), but the physiological cause of the diarrhea associated with this disease is unclear. We investigated whether loss of MYO5B results in aberrant expression of apical enterocyte transporters. METHODS: We studied alterations in apical membrane transporters in MYO5B-knockout mice, as well as mice with tamoxifen-inducible, intestine-specific disruption of Myo5b (VilCre(ERT2);Myo5b(flox/flox) mice) or those not given tamoxifen (controls). Intestinal tissues were collected from mice and analyzed by immunostaining, immunoelectron microscopy, or cultured enteroids were derived. Functions of brush border transporters in intestinal mucosa were measured in Ussing chambers. We obtained duodenal biopsy specimens from individuals with MVID and individuals without MVID (controls) and compared transporter distribution by immunocytochemistry. RESULTS: Compared to intestinal tissues from littermate controls, intestinal tissues from MYO5B-knockout mice had decreased apical localization of SLC9A3 (also called NHE3), SLC5A1 (also called SGLT1), aquaporin (AQP) 7, and sucrase isomaltase, and subapical localization of intestinal alkaline phosphatase and CDC42. However, CFTR was present on apical membranes of enterocytes from MYO5B knockout and control mice. Intestinal biopsies from patients with MVID had subapical localization of NHE3, SGLT1, and AQP7, but maintained apical CFTR. After tamoxifen administration, VilCre(ERT2);Myo5b(flox/flox) mice lost apical NHE3, SGLT1, DRA, and AQP7, similar to germline MYO5B knockout mice. Intestinal tissues from VilCre(ERT2);Myo5b(flox/flox) mice had increased CFTR in crypts and CFTR localized to the apical membranes of enterocytes. Intestinal mucosa from VilCre(ERT2);Myo5b(flox/flox) mice given tamoxifen did not have an intestinal barrier defect, based on Ussing chamber analysis, but did have decreased SGLT1 activity and increased CFTR activity. CONCLUSIONS: Although trafficking of many apical transporters is regulated by MYO5B, trafficking of CFTR is largely independent of MYO5B. Decreased apical localization of NHE3, SGLT1, DRA, and AQP7 might be responsible for dysfunctional water absorption in enterocytes of patients with MVID. Maintenance of apical CFTR might exacerbate water loss by active secretion of chloride into the intestinal lumen.

@article{engevik2018myo5b, abstract = {BACKGROUND & AIMS: Inactivating mutations in MYO5B cause microvillus inclusion disease (MVID), but the physiological cause of the diarrhea associated with this disease is unclear. We investigated whether loss of MYO5B results in aberrant expression of apical enterocyte transporters. METHODS: We studied alterations in apical membrane transporters in MYO5B-knockout mice, as well as mice with tamoxifen-inducible, intestine-specific disruption of Myo5b (VilCre(ERT2);Myo5b(flox/flox) mice) or those not given tamoxifen (controls). Intestinal tissues were collected from mice and analyzed by immunostaining, immunoelectron microscopy, or cultured enteroids were derived. Functions of brush border transporters in intestinal mucosa were measured in Ussing chambers. We obtained duodenal biopsy specimens from individuals with MVID and individuals without MVID (controls) and compared transporter distribution by immunocytochemistry. RESULTS: Compared to intestinal tissues from littermate controls, intestinal tissues from MYO5B-knockout mice had decreased apical localization of SLC9A3 (also called NHE3), SLC5A1 (also called SGLT1), aquaporin (AQP) 7, and sucrase isomaltase, and subapical localization of intestinal alkaline phosphatase and CDC42. However, CFTR was present on apical membranes of enterocytes from MYO5B knockout and control mice. Intestinal biopsies from patients with MVID had subapical localization of NHE3, SGLT1, and AQP7, but maintained apical CFTR. After tamoxifen administration, VilCre(ERT2);Myo5b(flox/flox) mice lost apical NHE3, SGLT1, DRA, and AQP7, similar to germline MYO5B knockout mice. Intestinal tissues from VilCre(ERT2);Myo5b(flox/flox) mice had increased CFTR in crypts and CFTR localized to the apical membranes of enterocytes. Intestinal mucosa from VilCre(ERT2);Myo5b(flox/flox) mice given tamoxifen did not have an intestinal barrier defect, based on Ussing chamber analysis, but did have decreased SGLT1 activity and increased CFTR activity. CONCLUSIONS: Although trafficking of many apical transporters is regulated by MYO5B, trafficking of CFTR is largely independent of MYO5B. Decreased apical localization of NHE3, SGLT1, DRA, and AQP7 might be responsible for dysfunctional water absorption in enterocytes of patients with MVID. Maintenance of apical CFTR might exacerbate water loss by active secretion of chloride into the intestinal lumen.}, added-at = {2024-02-15T15:08:22.000+0100}, author = {Engevik, A. C. and Kaji, I. and Engevik, M. A. and Meyer, A. R. and Weis, V. G. and Goldstein, A. and Hess, M. W. and Muller, T. and Koepsell, H. and Dudeja, P. K. and Tyska, M. and Huber, L. A. and Shub, M. D. and Ameen, N. and Goldenring, J. R.}, biburl = {https://www.bibsonomy.org/bibtex/21748919d9bbbc969b71544a36479da3f/jvsi_all}, doi = {10.1053/j.gastro.2018.08.025}, interhash = {5b1f55de4fdd71aa4758081d7d15612a}, intrahash = {1748919d9bbbc969b71544a36479da3f}, issn = {1528-0012 (Electronic) 0016-5085 (Print) 0016-5085 (Linking)}, journal = {Gastroenterology}, keywords = {Animals myOwn}, note = {Engevik, Amy C Kaji, Izumi Engevik, Melinda A Meyer, Anne R Weis, Victoria G Goldstein, Anna Hess, Michael W Muller, Thomas Koepsell, Hermann Dudeja, Pradeep K Tyska, Matthew Huber, Lukas A Shub, Mitchell D Ameen, Nadia Goldenring, James R eng R01 DK048370/DK/NIDDK NIH HHS/ T32 DK007673/DK/NIDDK NIH HHS/ P30 DK058404/DK/NIDDK NIH HHS/ R01 DK054016/DK/NIDDK NIH HHS/ F32 DK111101/DK/NIDDK NIH HHS/ I01 BX002011/BX/BLRD VA/ R01 DK070856/DK/NIDDK NIH HHS/ F31 DK117592/DK/NIDDK NIH HHS/ IS1 BX003097/BX/BLRD VA/ R01 DK081858/DK/NIDDK NIH HHS/ R01 DK111949/DK/NIDDK NIH HHS/ R01 DK077065/DK/NIDDK NIH HHS/ R01 DK095811/DK/NIDDK NIH HHS/ T32 CA106183/CA/NCI NIH HHS/ R01 DK092441/DK/NIDDK NIH HHS/ RC2 DK118640/DK/NIDDK NIH HHS/ P30 CA068485/CA/NCI NIH HHS/ T32 GM008554/GM/NIGMS NIH HHS/ Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2018/08/26 Gastroenterology. 2018 Dec;155(6):1883-1897.e10. doi: 10.1053/j.gastro.2018.08.025. Epub 2018 Aug 23.}, number = 6, pages = {1883-1897 e10}, timestamp = {2024-02-15T15:08:22.000+0100}, title = {Loss of MYO5B Leads to Reductions in Na(+) Absorption With Maintenance of CFTR-Dependent Cl(-) Secretion in Enterocytes}, type = {Journal Article}, url = {https://www.ncbi.nlm.nih.gov/pubmed/30144427}, volume = 155, year = 2018 }