The highly expressed calcium-insensitive synaptotagmin-11 and synaptotagmin-13 modulate insulin secretion
(2022) In Acta Physiologica 236(1).- Abstract
AIM: SYT11 and SYT13, two calcium-insensitive synaptotagmins, are downregulated in islets from type-2 diabetic donors, but their function in insulin secretion is unknown. To address this, we investigated the physiological role of these two synaptotagmins in insulin secreting cells.
METHODS: Correlations between gene expression levels were performed using previously described RNA-seq data on islets from 188 human donors. SiRNA knockdown was performed in EndoC-βH1 and INS-1 832/13 cells. Insulin secretion was measured with ELISA. Patch clamp was used for single cell electrophysiology. Confocal microscopy was used to determine intra-cellular localization.
RESULTS: Human islet expression of the transcription factor PDX-1 was... (More)
AIM: SYT11 and SYT13, two calcium-insensitive synaptotagmins, are downregulated in islets from type-2 diabetic donors, but their function in insulin secretion is unknown. To address this, we investigated the physiological role of these two synaptotagmins in insulin secreting cells.
METHODS: Correlations between gene expression levels were performed using previously described RNA-seq data on islets from 188 human donors. SiRNA knockdown was performed in EndoC-βH1 and INS-1 832/13 cells. Insulin secretion was measured with ELISA. Patch clamp was used for single cell electrophysiology. Confocal microscopy was used to determine intra-cellular localization.
RESULTS: Human islet expression of the transcription factor PDX-1 was positively correlated with SYT11 (p = 2.4e
-10 ) and SYT13 (p<2.2 e
-16 ). Syt11 and Syt13 both co-localized with insulin, indicating their localization in insulin granules. Downregulation of Syt11 in INS-1 832/13 cells (siSYT11) resulted in increased basal and glucose-induced insulin secretion. Downregulation of Syt13 (siSYT13) decreased insulin secretion induced by glucose and K
+ .Interestingly, the cAMP raising agent forskolin was unable to enhance insulin secretion in siSYT13 cells. There was no difference in insulin content, exocytosis, or voltage-gated Ca
2+ currents in the two models. Double knockdown of Syt11 and Syt13 (DKD) resembled the results in siSYT13 cells.
CONCLUSION: SYT11 and SYT13 have similar localization and transcriptional regulation but they regulate insulin secretion differentially. While downregulation of SYT11 might be a compensatory mechanism in type-2 diabetes, downregulation of SYT13 reduces the insulin secretory response and overrules the compensatory regulation of SYT11 in a way that could aggravate the disease.
(Less)
- author
- Ofori, Jones K LU ; Karagiannopoulos, Alexandros LU ; Barghouth, Mohammad LU ; Nagao, Mototsugu LU ; Andersson, Markus E LU ; Salunkhe, Vishal A LU ; Zhang, Enming LU ; Wendt, Anna LU and Eliasson, Lena LU
- organization
- publishing date
- 2022
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Acta Physiologica
- volume
- 236
- issue
- 1
- publisher
- Wiley-Blackwell
- external identifiers
-
- pmid:35753051
- scopus:85133212893
- ISSN
- 1748-1716
- DOI
- 10.1111/apha.13857
- language
- English
- LU publication?
- yes
- additional info
- This article is protected by copyright. All rights reserved.
- id
- c125c0fd-2ca7-4ef5-8812-8855717dacbf
- date added to LUP
- 2022-06-28 21:02:58
- date last changed
- 2024-09-19 22:54:58
@article{c125c0fd-2ca7-4ef5-8812-8855717dacbf, abstract = {{<p>AIM: SYT11 and SYT13, two calcium-insensitive synaptotagmins, are downregulated in islets from type-2 diabetic donors, but their function in insulin secretion is unknown. To address this, we investigated the physiological role of these two synaptotagmins in insulin secreting cells.</p><p>METHODS: Correlations between gene expression levels were performed using previously described RNA-seq data on islets from 188 human donors. SiRNA knockdown was performed in EndoC-βH1 and INS-1 832/13 cells. Insulin secretion was measured with ELISA. Patch clamp was used for single cell electrophysiology. Confocal microscopy was used to determine intra-cellular localization.</p><p>RESULTS: Human islet expression of the transcription factor PDX-1 was positively correlated with SYT11 (p = 2.4e<br> -10 ) and SYT13 (p<2.2 e<br> -16 ). Syt11 and Syt13 both co-localized with insulin, indicating their localization in insulin granules. Downregulation of Syt11 in INS-1 832/13 cells (siSYT11) resulted in increased basal and glucose-induced insulin secretion. Downregulation of Syt13 (siSYT13) decreased insulin secretion induced by glucose and K<br> + .Interestingly, the cAMP raising agent forskolin was unable to enhance insulin secretion in siSYT13 cells. There was no difference in insulin content, exocytosis, or voltage-gated Ca<br> 2+ currents in the two models. Double knockdown of Syt11 and Syt13 (DKD) resembled the results in siSYT13 cells.<br> </p><p>CONCLUSION: SYT11 and SYT13 have similar localization and transcriptional regulation but they regulate insulin secretion differentially. While downregulation of SYT11 might be a compensatory mechanism in type-2 diabetes, downregulation of SYT13 reduces the insulin secretory response and overrules the compensatory regulation of SYT11 in a way that could aggravate the disease.</p>}}, author = {{Ofori, Jones K and Karagiannopoulos, Alexandros and Barghouth, Mohammad and Nagao, Mototsugu and Andersson, Markus E and Salunkhe, Vishal A and Zhang, Enming and Wendt, Anna and Eliasson, Lena}}, issn = {{1748-1716}}, language = {{eng}}, number = {{1}}, publisher = {{Wiley-Blackwell}}, series = {{Acta Physiologica}}, title = {{The highly expressed calcium-insensitive synaptotagmin-11 and synaptotagmin-13 modulate insulin secretion}}, url = {{http://dx.doi.org/10.1111/apha.13857}}, doi = {{10.1111/apha.13857}}, volume = {{236}}, year = {{2022}}, }