Liraglutide protects pancreatic β cells from endoplasmic reticulum stress by upregulating MANF to promote autophagy turnover
Jili Fu
Liraglutide protects pancreatic β cells from endoplasmic reticulum stress by upregulating MANF to promote autophagy turnover - Mwanza, Tanzania: Pergamon & Catholic University of Health and Allied Sciences [CUHAS – Bugando] 2020/7/1 - Pages 117648 - Life sciences Volume 252 .
Abstract:
Aims: This study was conducted to determine the relationship between mesencephalic astrocyte-derived neurotrophic factor (MANF), autophagy and endoplasmic reticulum (ER) stress, and whether liraglutide (LRG) can protect β cells, promote autophagy and alleviate ER stress by regulating MANF expression.
Main methods: Human serum samples were collected from healthy controls (NC), simple hyperlipidemia (HLD), and newly diagnosed type 2 diabetes (T2D). The MANF levels were detected using ELISA. In vitro, after the mouse islet MIN6 cells were treated with glucose (GLU), palmitate (PA), thapsigargin (TG), LRG, and chloroquine (CQ), cell proliferation was detected using cell counting kit-8 (CCK-8), apoptosis-related protein cleaved caspase 3 (C-cas-3), ER stress, and autophagy-related proteins were detected by Western blotting, MANF, insulin, and C-cas-3 proteins were detected via immunofluorescence. Subcellular structures and autophagosomes were examined using electron microscopy.
Key findings: Compared with the NC group, the MANF levels in the HLD and T2D groups increased significantly. After ER stress induced by GLU, PA, and TG, cell viability decreased, while MANF, c-cas3, ERS, and autophagy-related proteins increased, which was related to the concentration of GLU, PA, and TG. Compared with the BSA group, the number of mitochondria and autophagosomes in the PA group increased and the mitochondria were damaged. In the PA and TG plus CQ groups, the effect was further exaggerated. But after co-treatment with LRG, the effects of GLU, PA, and TG were attenuated.
Significance: LRG protects islet β cells from ER stress by upregulating MANF to promote autophagy turnover. = Liraglutide MANF Autophagy Endoplasmic reticulum stress β cells = Abbreviations AKTserine/threonine kinase ATF4activating transcription factor 4 ATF6activating transcription factor 6 BSAbull serum albumin C-cas-3cleaved-caspase-3 CCK-8cell counting kit-8 CHOPC/EBP homologous protein CQchloroquine DMSOdimethyl sulfoxide ECLenhanced chemiluminescence ERendoplasmic reticulum FFAfree fatty acid GLUglucose HLDhyperlipidemia IRE1αinositol-requiring enzyme 1α LC3Bmicrotubule-associated protein 1 light chain 3B LRGliraglutide MANFmesencephalic astrocyte derived neurotrophic factor mTORmammalian target of rapamycin PApalmitate p-AKTphosphorylation serine/threonine kinase PBSphosphate buffered saline p-mTORmammalian target phosphorylated of rapamycin PMSFphenylrnethanesulfony1 fluoride p62/SQSTM1sequestosome 1 PVDFpolyvinylidene difluoride rpmrevolutions per minute T2Dtype 2 diabetes TBStri buffered saline TBSTtris-buffered saline with tween TEMtransmission electron microscope TGthapsigargin UPRunfolded protein response XBP-1sX-box binding protein 1 spliced
Phone: +255 28 298 3384 Fax: +255 28 298 3386 Email: vc@bugando.ac.tz Website: www.bugando.ac.tz
Liraglutide protects pancreatic β cells from endoplasmic reticulum stress by upregulating MANF to promote autophagy turnover - Mwanza, Tanzania: Pergamon & Catholic University of Health and Allied Sciences [CUHAS – Bugando] 2020/7/1 - Pages 117648 - Life sciences Volume 252 .
Abstract:
Aims: This study was conducted to determine the relationship between mesencephalic astrocyte-derived neurotrophic factor (MANF), autophagy and endoplasmic reticulum (ER) stress, and whether liraglutide (LRG) can protect β cells, promote autophagy and alleviate ER stress by regulating MANF expression.
Main methods: Human serum samples were collected from healthy controls (NC), simple hyperlipidemia (HLD), and newly diagnosed type 2 diabetes (T2D). The MANF levels were detected using ELISA. In vitro, after the mouse islet MIN6 cells were treated with glucose (GLU), palmitate (PA), thapsigargin (TG), LRG, and chloroquine (CQ), cell proliferation was detected using cell counting kit-8 (CCK-8), apoptosis-related protein cleaved caspase 3 (C-cas-3), ER stress, and autophagy-related proteins were detected by Western blotting, MANF, insulin, and C-cas-3 proteins were detected via immunofluorescence. Subcellular structures and autophagosomes were examined using electron microscopy.
Key findings: Compared with the NC group, the MANF levels in the HLD and T2D groups increased significantly. After ER stress induced by GLU, PA, and TG, cell viability decreased, while MANF, c-cas3, ERS, and autophagy-related proteins increased, which was related to the concentration of GLU, PA, and TG. Compared with the BSA group, the number of mitochondria and autophagosomes in the PA group increased and the mitochondria were damaged. In the PA and TG plus CQ groups, the effect was further exaggerated. But after co-treatment with LRG, the effects of GLU, PA, and TG were attenuated.
Significance: LRG protects islet β cells from ER stress by upregulating MANF to promote autophagy turnover. = Liraglutide MANF Autophagy Endoplasmic reticulum stress β cells = Abbreviations AKTserine/threonine kinase ATF4activating transcription factor 4 ATF6activating transcription factor 6 BSAbull serum albumin C-cas-3cleaved-caspase-3 CCK-8cell counting kit-8 CHOPC/EBP homologous protein CQchloroquine DMSOdimethyl sulfoxide ECLenhanced chemiluminescence ERendoplasmic reticulum FFAfree fatty acid GLUglucose HLDhyperlipidemia IRE1αinositol-requiring enzyme 1α LC3Bmicrotubule-associated protein 1 light chain 3B LRGliraglutide MANFmesencephalic astrocyte derived neurotrophic factor mTORmammalian target of rapamycin PApalmitate p-AKTphosphorylation serine/threonine kinase PBSphosphate buffered saline p-mTORmammalian target phosphorylated of rapamycin PMSFphenylrnethanesulfony1 fluoride p62/SQSTM1sequestosome 1 PVDFpolyvinylidene difluoride rpmrevolutions per minute T2Dtype 2 diabetes TBStri buffered saline TBSTtris-buffered saline with tween TEMtransmission electron microscope TGthapsigargin UPRunfolded protein response XBP-1sX-box binding protein 1 spliced
Phone: +255 28 298 3384 Fax: +255 28 298 3386 Email: vc@bugando.ac.tz Website: www.bugando.ac.tz