Cinacalcet-mediated activation of the CaMKKβ-LKB1-AMPK pathway attenuates diabetic nephropathy in db/db mice by modulation of apoptosis and autophagy

Cell Death Dis. 2018 Feb 15;9(3):270. doi: 10.1038/s41419-018-0324-4.

Abstract

Apoptosis and autophagy are harmoniously regulated biological processes for maintaining tissue homeostasis. AMP-activated protein kinase (AMPK) functions as a metabolic sensor to coordinate cellular survival and function in various organs, including the kidney. We investigated the renoprotective effects of cinacalcet in high-glucose treated human glomerular endothelial cells (HGECs), murine podocytes and C57BLKS/J-db/db mice. In cultured HGECs and podocytes, cinacalcet decreased oxidative stress and apoptosis and increased autophagy that were attributed to the increment of intracellular Ca2+ concentration and the phosphorylation of Ca2+/calmodulin-dependent protein kinase kinaseβ (CaMKKβ)-Liver kinase B1 (LKB1)-AMPK and their downstream signals including the phosphorylation of endothelial nitric oxide synthase (eNOS) and increases in superoxide dismutases and B cell leukemia/lymphoma 2/BCL-2-associated X protein expression. Interestingly, intracellular chelator BAPTA-AM reversed cinacalcet-induced CaMKKβ elevation and LKB1 phosphorylation. Cinacalcet reduced albuminuria without influencing either blood glucose or Ca2+ concentration and ameliorated diabetes-induced renal damage, which were related to the increased expression of calcium-sensing receptor and the phosphorylation of CaMKKβ-LKB1. Subsequent activation of AMPK was followed by the activation of peroxisome proliferator-activated receptor γ coactivator-1α and phospho-Ser1177eNOS-nitric oxide, resulting in a decrease in apoptosis and oxidative stress as well as an increase in autophagy.Our results suggest that cinacalcet increases intracellular Ca2+ followed by an activation of CaMKKβ-LKB1-AMPK signaling in GECs and podocytes in the kidney, which provides a novel therapeutic means for type 2 diabetic nephropathy by modulation of apoptosis and autophagy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / genetics
  • AMP-Activated Protein Kinases / metabolism*
  • Albuminuria / enzymology
  • Albuminuria / pathology
  • Albuminuria / prevention & control
  • Animals
  • Apoptosis / drug effects*
  • Autophagy / drug effects*
  • Calcium-Calmodulin-Dependent Protein Kinase Kinase / genetics
  • Calcium-Calmodulin-Dependent Protein Kinase Kinase / metabolism*
  • Cells, Cultured
  • Cinacalcet / pharmacology*
  • Diabetic Nephropathies / enzymology
  • Diabetic Nephropathies / genetics
  • Diabetic Nephropathies / pathology
  • Diabetic Nephropathies / prevention & control*
  • Disease Models, Animal
  • Endothelial Cells / drug effects
  • Endothelial Cells / enzymology
  • Endothelial Cells / pathology
  • Enzyme Activation
  • Humans
  • Kidney Glomerulus / drug effects*
  • Kidney Glomerulus / enzymology
  • Kidney Glomerulus / pathology
  • Male
  • Mice, Inbred C57BL
  • Nitric Oxide Synthase Type III / metabolism
  • Oxidative Stress / drug effects
  • Phosphorylation
  • Podocytes / drug effects
  • Podocytes / enzymology
  • Podocytes / pathology
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Signal Transduction

Substances

  • Nitric Oxide Synthase Type III
  • Nos3 protein, mouse
  • Protein Serine-Threonine Kinases
  • Stk11 protein, mouse
  • Calcium-Calmodulin-Dependent Protein Kinase Kinase
  • AMP-Activated Protein Kinases
  • Cinacalcet