Blockade of MCU-Mediated Ca2+ Uptake Perturbs Lipid Metabolism via PP4-Dependent AMPK Dephosphorylation

Dhanendra Tomar; Fabián Jaña; Zhiwei Dong; William J Quinn 3rd; Pooja Jadiya; Sarah L Breves; Cassidy C Daw; Subramanya Srikantan; Santhanam Shanmughapriya; Neeharika Nemani; Edmund Carvalho; Aparna Tripathi; Alison M Worth; Xueqian Zhang; Roshanak Razmpour; Ajay Seelam; Stephen Rhode; Anuj V Mehta; Michael Murray; Daniel Slade; Servio H Ramirez; Prashant Mishra; Glenn S Gerhard; Jeffrey Caplan; Luke Norton; Kumar Sharma; Sudarsan Rajan; Darius Balciunas; Dayanjan S Wijesinghe; Rexford S Ahima; Joseph A Baur; Muniswamy Madesh

doi:10.1016/j.celrep.2019.02.107

Blockade of MCU-Mediated Ca²⁺ Uptake Perturbs Lipid Metabolism via PP4-Dependent AMPK Dephosphorylation

Cell Rep. 2019 Mar 26;26(13):3709-3725.e7. doi: 10.1016/j.celrep.2019.02.107.

Authors

Dhanendra Tomar¹, Fabián Jaña¹, Zhiwei Dong¹, William J Quinn 3rd², Pooja Jadiya³, Sarah L Breves¹, Cassidy C Daw⁴, Subramanya Srikantan⁴, Santhanam Shanmughapriya¹, Neeharika Nemani¹, Edmund Carvalho¹, Aparna Tripathi¹, Alison M Worth¹, Xueqian Zhang³, Roshanak Razmpour⁵, Ajay Seelam¹, Stephen Rhode¹, Anuj V Mehta⁶, Michael Murray¹, Daniel Slade¹, Servio H Ramirez⁵, Prashant Mishra⁷, Glenn S Gerhard⁸, Jeffrey Caplan⁹, Luke Norton¹⁰, Kumar Sharma⁴, Sudarsan Rajan¹, Darius Balciunas¹¹, Dayanjan S Wijesinghe¹², Rexford S Ahima¹³, Joseph A Baur², Muniswamy Madesh¹⁴

Affiliations

¹ Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
² Department of Physiology and Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
³ Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
⁴ Department of Medicine and Nephrology, Center for Precision Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA.
⁵ Department of Pathology and Laboratory Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
⁶ Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Department of Biology, Temple University, Philadelphia, PA 19122, USA.
⁷ Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
⁸ Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
⁹ Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA.
¹⁰ Diabetes Division, University of Texas Health Science Center, San Antonio, TX, USA.
¹¹ Department of Biology, Temple University, Philadelphia, PA 19122, USA.
¹² Department of Surgery, Virginia Commonwealth University, Richmond, VA 23298, USA.
¹³ Division of Endocrinology, Diabetes and Metabolism, John Hopkins University School of Medicine, Baltimore, MD 21287, USA.
¹⁴ Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Department of Medicine and Nephrology, Center for Precision Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA. Electronic address: [email protected].

Abstract

Mitochondrial Ca²⁺ uniporter (MCU)-mediated Ca²⁺ uptake promotes the buildup of reducing equivalents that fuel oxidative phosphorylation for cellular metabolism. Although MCU modulates mitochondrial bioenergetics, its function in energy homeostasis in vivo remains elusive. Here we demonstrate that deletion of the Mcu gene in mouse liver (MCU^Δhep) and in Danio rerio by CRISPR/Cas9 inhibits mitochondrial Ca²⁺ (_mCa²⁺) uptake, delays cytosolic Ca²⁺ (_cCa²⁺) clearance, reduces oxidative phosphorylation, and leads to increased lipid accumulation. Elevated hepatic lipids in MCU^Δhep were a direct result of extramitochondrial Ca²⁺-dependent protein phosphatase-4 (PP4) activity, which dephosphorylates AMPK. Loss of AMPK recapitulates hepatic lipid accumulation without changes in MCU-mediated Ca²⁺ uptake. Furthermore, reconstitution of active AMPK, or PP4 knockdown, enhances lipid clearance in MCU^Δhep hepatocytes. Conversely, gain-of-function MCU promotes rapid _mCa²⁺ uptake, decreases PP4 levels, and reduces hepatic lipid accumulation. Thus, our work uncovers an MCU/PP4/AMPK molecular cascade that links Ca²⁺ dynamics to hepatic lipid metabolism.

Keywords: AMPK; MCU; bioenergetics; calcium; diabetes; hepatocyte; lipid metabolism; metabolic diseases; mitochondrial Ca(2+) uniporter; phosphatase.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

AMP-Activated Protein Kinase Kinases
Animals
Calcium / metabolism*
Calcium Channels / genetics
Calcium Channels / metabolism*
Cells, Cultured
Female
Hep G2 Cells
Hepatocytes / metabolism*
Humans
Lipid Metabolism*
Male
Mice
Mice, Inbred C57BL
Mitochondria, Liver / metabolism
Mitochondrial Proteins / genetics
Mitochondrial Proteins / metabolism*
Phosphoprotein Phosphatases / metabolism
Protein Kinases / metabolism
Zebrafish

Substances

Calcium Channels
Mcu protein, mouse
Mitochondrial Proteins
Protein Kinases
AMP-Activated Protein Kinase Kinases
Phosphoprotein Phosphatases
protein phosphatase 4
Calcium

Abstract

Publication types

MeSH terms

Substances

Grants and funding