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Asahara S, Shibutani Y, Teruyama K, Inoue HY, Kawada Y, Etoh H, Matsuda T, Kimura-Koyanagi M, Hashimoto N, Sakahara M, Fujimoto W, Takahashi H, Ueda S, Hosooka T, Satoh T, Inoue H, Matsumoto M, Aiba A, Kasuga M, Kido Y. Ras-related C3 botulinum toxin substrate 1 (RAC1) regulates glucose-stimulated insulin secretion via modulation of F-actin. Diabetologia 2013; 56:1088-97. [PMID: 23412604 PMCID: PMC3622740 DOI: 10.1007/s00125-013-2849-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 01/17/2013] [Indexed: 11/03/2022]
Abstract
AIMS/HYPOTHESIS The small G-protein ras-related C3 botulinum toxin substrate 1 (RAC1) plays various roles in mammalian cells, such as in the regulation of cytoskeletal organisation, cell adhesion, migration and morphological changes. The present study examines the effects of RAC1 ablation on pancreatic beta cell function. METHODS Isolated islets from pancreatic beta cell-specific Rac1-knockout (betaRac1(-/-)) mice and RAC1 knockdown INS-1 insulinoma cells treated with small interfering RNA were used to investigate insulin secretion and cytoskeletal organisation in pancreatic beta cells. RESULTS BetaRac1(-/-) mice showed decreased glucose-stimulated insulin secretion, while there were no apparent differences in islet morphology. Isolated islets from the mice had blunted insulin secretion in response to high glucose levels. In RAC1 knockdown INS-1 cells, insulin secretion was also decreased in response to high glucose levels, consistent with the phenotype of betaRac1(-/-) mice. Even under high glucose levels, RAC1 knockdown INS-1 cells remained intact with F-actin, which inhibits the recruitment of the insulin granules, resulting in an inhibition of insulin secretion. CONCLUSIONS/INTERPRETATION In RAC1-deficient pancreatic beta cells, F-actin acts as a barrier for insulin granules and reduces glucose-stimulated insulin secretion.
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Affiliation(s)
- S. Asahara
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Y. Shibutani
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - K. Teruyama
- Division of Medical Chemistry, Kobe University Graduate School of Health Sciences, Kobe, 654-0142 Japan
| | - H. Y. Inoue
- Division of Medical Chemistry, Kobe University Graduate School of Health Sciences, Kobe, 654-0142 Japan
| | - Y. Kawada
- Division of Medical Chemistry, Kobe University Graduate School of Health Sciences, Kobe, 654-0142 Japan
| | - H. Etoh
- Division of Medical Chemistry, Kobe University Graduate School of Health Sciences, Kobe, 654-0142 Japan
| | - T. Matsuda
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - M. Kimura-Koyanagi
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - N. Hashimoto
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - M. Sakahara
- Cancer Institute, Japanese Foundation of Cancer Research, Tokyo, Japan
| | - W. Fujimoto
- Division of Cellular and Molecular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - H. Takahashi
- Division of Cellular and Molecular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - S. Ueda
- Kobe University Graduate School of Agricultural Science, Kobe, Japan
| | - T. Hosooka
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - T. Satoh
- Division of Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - H. Inoue
- Department of Physiology and Metabolism, Brain/Liver Interface Medicine Research Center, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - M. Matsumoto
- Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - A. Aiba
- Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - M. Kasuga
- Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Y. Kido
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, Japan
- Division of Medical Chemistry, Kobe University Graduate School of Health Sciences, Kobe, 654-0142 Japan
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Reiche EM, Morimoto HK, Farias GN, Hisatsugu KR, Geller L, Gomes AC, Inoue HY, Rodrigues G, Matsuo T. [Prevalence of American trypanosomiasis, syphilis, toxoplasmosis, rubella, hepatitis B, hepatitis C, human immunodeficiency virus infection, assayed through serological tests among pregnant patients, from 1996 to 1998, at the Regional University Hospital Norte do Paraná]. Rev Soc Bras Med Trop 2000; 33:519-27. [PMID: 11175581 DOI: 10.1590/s0037-86822000000600002] [Citation(s) in RCA: 31] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In order to evaluate the seroprevalence of the american trypanosomiasis, syphilis, toxoplasmosis, rubella, hepatitis B infection, hepatitis C infection and human immunodeficiency virus infection among pregnant women attended at the Hospital Universitário Regional Norte do Paraná, Londrina State University, Paraná, a retrospective study of the serologic results performed in the prenatal routine during the period of June 1996 to June 1998 was carried out. The rates of seropositivity were as follows: american trypanosomiasis = 0.9%, syphilis = 1.6%, toxoplasmosis = 67% (IgG) and 1.8% (IgM), rubella = 89% (IgG) and 1.2% (IgM), hepatitis B surface antigen = 0.8%, hepatitis C virus = 0.8% and human immunodeficiency virus infection = 0.6%. An association between the increase in the seroprevalence of Chagas' disease and patient age was detected (p=0.006). The results underscore the importance of the serological tests in perinatal care, to prevent both the congenital and perinatally transmitted forms of theses infectious diseases.
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Affiliation(s)
- E M Reiche
- Departamento de Patologia Aplicada, Legislação e Deontologia, Centro de Ciências da Saúde, Universidade Estadual de Londrina, Londrina, Paraná, Brazil.
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