|
1
|
Ninagawa S, Tada S, Okumura M, Inoguchi K, Kinoshita M, Kanemura S, Imami K, Umezawa H, Ishikawa T, Mackin RB, Torii S, Ishihama Y, Inaba K, Anazawa T, Nagamine T, Mori K. Antipsychotic olanzapine-induced misfolding of proinsulin in the endoplasmic reticulum accounts for atypical development of diabetes. eLife 2020; 9:60970. [PMID: 33198886 PMCID: PMC7671685 DOI: 10.7554/elife.60970] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/22/2020] [Indexed: 12/20/2022] Open
Abstract
Second-generation antipsychotics are widely used to medicate patients with schizophrenia, but may cause metabolic side effects such as diabetes, which has been considered to result from obesity-associated insulin resistance. Olanzapine is particularly well known for this effect. However, clinical studies have suggested that olanzapine-induced hyperglycemia in certain patients cannot be explained by such a generalized mechanism. Here, we focused on the effects of olanzapine on insulin biosynthesis and secretion by mouse insulinoma MIN6 cells. Olanzapine reduced maturation of proinsulin, and thereby inhibited secretion of insulin; and specifically shifted the primary localization of proinsulin from insulin granules to the endoplasmic reticulum. This was due to olanzapine's impairment of proper disulfide bond formation in proinsulin, although direct targets of olanzapine remain undetermined. Olanzapine-induced proinsulin misfolding and subsequent decrease also occurred at the mouse level. This mechanism of olanzapine-induced β-cell dysfunction should be considered, together with weight gain, when patients are administered olanzapine.
Collapse
Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Seiichiro Tada
- Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masaki Okumura
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Kenta Inoguchi
- Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Misaki Kinoshita
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Shingo Kanemura
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan.,School of Science and Technology, Kwansei Gakuin University, Sanda, Japan
| | - Koshi Imami
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hajime Umezawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Tokiro Ishikawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Robert B Mackin
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, United States
| | - Seiji Torii
- Laboratory of Secretion Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Yasushi Ishihama
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| | - Takayuki Anazawa
- Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| |
Collapse
|
|
2
|
Hormones Secretion and Rho GTPases in Neuroendocrine Tumors. Cancers (Basel) 2020; 12:cancers12071859. [PMID: 32664294 PMCID: PMC7408961 DOI: 10.3390/cancers12071859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 12/14/2022] Open
Abstract
Neuroendocrine tumors (NETs) belong to a heterogeneous group of neoplasms arising from hormone secreting cells. These tumors are often associated with a dysfunction of their secretory activity. Neuroendocrine secretion occurs through calcium-regulated exocytosis, a process that is tightly controlled by Rho GTPases family members. In this review, we compiled the numerous mutations and modification of expression levels of Rho GTPases or their regulators (Rho guanine nucleotide-exchange factors and Rho GTPase-activating proteins) that have been identified in NETs. We discussed how they might regulate neuroendocrine secretion.
Collapse
|