TY - JOUR
T1 - BNIP3L/Nix-induced mitochondrial fission, mitophagy, and impaired myocyte glucose uptake are abrogated by PRKA/PKA phosphorylation
AU - da Silva Rosa, Simone C.
AU - Martens, Matthew D.
AU - Field, Jared T.
AU - Nguyen, Lucas
AU - Kereliuk, Stephanie M.
AU - Hai, Yan
AU - Chapman, Donald
AU - Diehl-Jones, William
AU - Aliani, Michel
AU - West, Adrian R.
AU - Thliveris, James
AU - Ghavami, Saeid
AU - Rampitsch, Christof
AU - Dolinsky, Vernon W.
AU - Gordon, Joseph W.
N1 - Funding Information:
This work was supported by the Canadian Institutes of Health Research [N/A]; Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada [N/A]; Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada [N/A]; Children’s Hospital Research Institute of Manitoba [N/A]. This work was support by the Natural Science and Engineering Research Council (NSERC) Canada, through Discovery Grants to JWG and ARW. Seed funding was provided by the Children’s Hospital Research Institute of Manitoba, the DREAM research theme, and the Manitoba Centre for Nursing and Health Research. V.W.D is supported by CIHR and is the Allen Rouse Basic Scientist of the Manitoba Medical Services Foundation. J.W.G., A.R.W., and V.W.D are members of the DEVOTION Research Cluster. Open access support was provided by the College of Nursing Endowment Fund, University of Manitoba. S.C.d.S.R. is supported by a University of Manitoba Graduate Studentship, J.T.F. is supported by an Alexander Graham Bell studentship from NSERC Canada, and M.D.M. and S.M.K. are supported by a studentship from the Children’s Hospital Foundation of Manitoba and Research Manitoba. We wish to thank Drs. Christine Doucette and Grant Hatch for helpful discussions on the manuscript.
Funding Information:
This work was support by the Natural Science and Engineering Research Council (NSERC) Canada, through Discovery Grants to JWG and ARW. Seed funding was provided by the Children’s Hospital Research Institute of Manitoba, the DREAM research theme, and the Manitoba Centre for Nursing and Health Research. V.W.D is supported by CIHR and is the Allen Rouse Basic Scientist of the Manitoba Medical Services Foundation. J.W.G., A.R.W., and V.W.D are members of the DEVOTION Research Cluster. Open access support was provided by the College of Nursing Endowment Fund, University of Manitoba. S.C.d.S.R. is supported by a University of Manitoba Graduate Studentship, J.T.F. is supported by an Alexander Graham Bell studentship from NSERC Canada, and M.D.M. and S.M.K. are supported by a studentship from the Children’s Hospital Foundation of Manitoba and Research Manitoba. We wish to thank Drs. Christine Doucette and Grant Hatch for helpful discussions on the manuscript.
Publisher Copyright:
© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
PY - 2021
Y1 - 2021
N2 - Lipotoxicity is a form of cellular stress caused by the accumulation of lipids resulting in mitochondrial dysfunction and insulin resistance in muscle. Previously, we demonstrated that the mitophagy receptor BNIP3L/Nix is responsive to lipotoxicity and accumulates in response to a high-fat (HF) feeding. To provide a better understanding of this observation, we undertook gene expression array and shot-gun metabolomics studies in soleus muscle from rodents on an HF diet. Interestingly, we observed a modest reduction in several autophagy-related genes. Moreover, we observed alterations in the fatty acyl composition of cardiolipins and phosphatidic acids. Given the reported roles of these phospholipids and BNIP3L in mitochondrial dynamics, we investigated aberrant mitochondrial turnover as a mechanism of impaired myocyte insulin signaling. In a series of gain-of-function and loss-of-function experiments in rodent and human myotubes, we demonstrate that BNIP3L accumulation triggers mitochondrial depolarization, calcium-dependent activation of DNM1L/DRP1, and mitophagy. In addition, BNIP3L can inhibit insulin signaling through activation of MTOR-RPS6KB/p70S6 kinase inhibition of IRS1, which is contingent on phosphatidic acids and RHEB. Finally, we demonstrate that BNIP3L-induced mitophagy and impaired glucose uptake can be reversed by direct phosphorylation of BNIP3L by PRKA/PKA, leading to the translocation of BNIP3L from the mitochondria and sarcoplasmic reticulum to the cytosol. These findings provide insight into the role of BNIP3L, mitochondrial turnover, and impaired myocyte insulin signaling during an overfed state when overall autophagy-related gene expression is reduced. Furthermore, our data suggest a mechanism by which exercise or pharmacological activation of PRKA may overcome myocyte insulin resistance. Abbreviations: BCL2: B cell leukemia/lymphoma 2; BNIP3L/Nix: BCL2/adenovirus E1B interacting protein 3-like; DNM1L/DRP1: dynamin 1-like; FUNDC1: FUN14 domain containing 1; IRS1: insulin receptor substrate 1; MAP1LC3A/LC3: microtubule-associated protein 1 light chain 3 alpha; MFN1: mitofusin 1; MFN2: mitofusin 2; MTOR: mechanistic target of rapamycin kinase; OPA1: OPA1 mitochondrial dynamin like GTPase; PDE4i: phosphodiesterase 4 inhibitor; PLD1: phospholipase D1; PLD6: phospholipase D family member 6; PRKA/PKA: protein kinase, AMP-activated; PRKCD/PKCδ: protein kinase C, delta; PRKCQ/PKCθ: protein kinase C, theta; RHEB: Ras homolog enriched in brain; RPS6KB/p70S6K: ribosomal protein S6 kinase; SQSTM1/p62: sequestosome 1; YWHAB/14-3-3β: tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein beta.
AB - Lipotoxicity is a form of cellular stress caused by the accumulation of lipids resulting in mitochondrial dysfunction and insulin resistance in muscle. Previously, we demonstrated that the mitophagy receptor BNIP3L/Nix is responsive to lipotoxicity and accumulates in response to a high-fat (HF) feeding. To provide a better understanding of this observation, we undertook gene expression array and shot-gun metabolomics studies in soleus muscle from rodents on an HF diet. Interestingly, we observed a modest reduction in several autophagy-related genes. Moreover, we observed alterations in the fatty acyl composition of cardiolipins and phosphatidic acids. Given the reported roles of these phospholipids and BNIP3L in mitochondrial dynamics, we investigated aberrant mitochondrial turnover as a mechanism of impaired myocyte insulin signaling. In a series of gain-of-function and loss-of-function experiments in rodent and human myotubes, we demonstrate that BNIP3L accumulation triggers mitochondrial depolarization, calcium-dependent activation of DNM1L/DRP1, and mitophagy. In addition, BNIP3L can inhibit insulin signaling through activation of MTOR-RPS6KB/p70S6 kinase inhibition of IRS1, which is contingent on phosphatidic acids and RHEB. Finally, we demonstrate that BNIP3L-induced mitophagy and impaired glucose uptake can be reversed by direct phosphorylation of BNIP3L by PRKA/PKA, leading to the translocation of BNIP3L from the mitochondria and sarcoplasmic reticulum to the cytosol. These findings provide insight into the role of BNIP3L, mitochondrial turnover, and impaired myocyte insulin signaling during an overfed state when overall autophagy-related gene expression is reduced. Furthermore, our data suggest a mechanism by which exercise or pharmacological activation of PRKA may overcome myocyte insulin resistance. Abbreviations: BCL2: B cell leukemia/lymphoma 2; BNIP3L/Nix: BCL2/adenovirus E1B interacting protein 3-like; DNM1L/DRP1: dynamin 1-like; FUNDC1: FUN14 domain containing 1; IRS1: insulin receptor substrate 1; MAP1LC3A/LC3: microtubule-associated protein 1 light chain 3 alpha; MFN1: mitofusin 1; MFN2: mitofusin 2; MTOR: mechanistic target of rapamycin kinase; OPA1: OPA1 mitochondrial dynamin like GTPase; PDE4i: phosphodiesterase 4 inhibitor; PLD1: phospholipase D1; PLD6: phospholipase D family member 6; PRKA/PKA: protein kinase, AMP-activated; PRKCD/PKCδ: protein kinase C, delta; PRKCQ/PKCθ: protein kinase C, theta; RHEB: Ras homolog enriched in brain; RPS6KB/p70S6K: ribosomal protein S6 kinase; SQSTM1/p62: sequestosome 1; YWHAB/14-3-3β: tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein beta.
KW - Insulin signaling
KW - MTOR
KW - Nix
KW - PKA
KW - mitochondria
KW - mitophagy
KW - muscle
UR - http://www.scopus.com/inward/record.url?scp=85092451639&partnerID=8YFLogxK
U2 - 10.1080/15548627.2020.1821548
DO - 10.1080/15548627.2020.1821548
M3 - Journal Article
C2 - 33044904
AN - SCOPUS:85092451639
SN - 1554-8627
VL - 17
SP - 2257
EP - 2272
JO - Autophagy
JF - Autophagy
IS - 9
ER -