Loading…

TDP-43 regulates early-phase insulin secretion via CaV1.2-mediated exocytosis in islets

TAR DNA-binding protein 43 kDa (TDP-43), encoded by TARDBP, is an RNA-binding protein, the nuclear depletion of which is the histopathological hallmark of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder affecting both upper and lower motor neurons. Besides motor symptoms, pat...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of clinical investigation 2019-09, Vol.130 (9), p.3578-3593
Main Authors: Araki, Kunihiko, Araki, Amane, Honda, Daiyu, Izumoto, Takako, Hashizume, Atsushi, Hijikata, Yasuhiro, Yamada, Shinichiro, Iguchi, Yohei, Hara, Akitoshi, Ikumi, Kazuhiro, Kawai, Kaori, Ishigaki, Shinsuke, Nakamichi, Yoko, Tsunekawa, Shin, Seino, Yusuke, Yamamoto, Akiko, Takayama, Yasunori, Hidaka, Shihomi, Tominaga, Makoto, Ohara-Imaizumi, Mica, Suzuki, Atsushi, Ishiguro, Hiroshi, Enomoto, Atsushi, Yoshida, Mari, Arima, Hiroshi, Muramatsu, Shin-Ichi, Sobue, Gen, Katsuno, Masahisa
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:TAR DNA-binding protein 43 kDa (TDP-43), encoded by TARDBP, is an RNA-binding protein, the nuclear depletion of which is the histopathological hallmark of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder affecting both upper and lower motor neurons. Besides motor symptoms, patients with ALS often develop nonneuronal signs including glucose intolerance, but the underlying pathomechanism is still controversial, i.e., whether it is impaired insulin secretion and/or insulin resistance. Here, we showed that ALS subjects reduced early-phase insulin secretion and that the nuclear localization of TDP-43 was lost in the islets of autopsied ALS pancreas. Loss of TDP-43 inhibited exocytosis by downregulating CaV1.2 calcium channels, thereby reducing early-phase insulin secretion in a cultured β cell line (MIN6) and β cell-specific Tardbp knockout mice. Overexpression of CaV1.2 restored early-phase insulin secretion in Tardbp knocked-down MIN6 cells. Our findings suggest that TDP-43 regulates cellular exocytosis mediated by L-type voltage-dependent calcium channels and thus plays an important role in the early phase of insulin secretion by pancreatic islets. Thus, nuclear loss of TDP-43 is implicated in not only the selective loss of motor neurons but also in glucose intolerance due to impaired insulin secretion at an early stage of ALS.
ISSN:0021-9738
1558-8238
DOI:10.1172/jci124481