title: Calhex₂₃₁ Ameliorates Cardiac Hypertrophy by Inhibiting Cellular Autophagy in Vivo and in Vitro.
abstract: OBJECTIVE
  Intracellular calcium concentration ([Ca2+]i) homeostasis, an initial factor of cardiac hypertrophy, is regulated by the calcium-sensing receptor (CaSR) and is associated with the formation of autolysosomes. The aim of this study was to investigate the role of Calhex231, a CaSR inhibitor, on the hypertrophic response via autophagy modulation.
  
  
  METHODS
  Cardiac hypertrophy was induced by transverse aortic constriction (TAC) in 40 male Wistar rats, while 10 rats underwent a sham operation and served as controls. Cardiac function was monitored by transthoracic echocardiography, and the hypertrophy index was calculated. Cardiac tissue was stained with hematoxylin and eosin (H&E) or Masson’s trichrome reagent and examined by transmission electron microscopy. An angiotensin II (Ang II)-induced cardiomyocyte hypertrophy model was established and used to test the involvement of active molecules. Intracellular calcium concentration ([Ca2+]i) was determined by the introduction of Fluo-4/AM dye followed by confocal microscopy. The expression of various active proteins was analyzed by western blot.
  
  
  RESULTS
  The rats with TAC-induced hypertrophy had an increased heart size, ratio of heart weight to body weight, myocardial fibrosis, and CaSR and autophagy levels, which were suppressed by Calhex231. Experimental results using Ang II-induced hypertrophic cardiomyocytes confirmed that Calhex231 suppressed CaSR expression and downregulated autophagy by inhibiting the Ca2+/calmodulin-dependent-protein kinase-kinase-β (CaMKKβ)– AMP-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR) pathway to ameliorate cardiomyocyte hypertrophy.
  
  
  CONCLUSIONS
  Calhex231 ameliorates myocardial hypertrophy induced by pressure-overload or Ang II via inhibiting CaSR expression and autophagy. Our results may support the notion that Calhex231 can become a new therapeutic agent for the treatment of cardiac hypertrophy.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Dianjun
authors.initials: D
authors.lastname: Sun
authors.forename: Shuangquan
authors.initials: S
authors.lastname: Jiang
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Weihua
authors.initials: W
authors.lastname: Zhang
authors.forename: Yajun
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Xi
authors.forename: Sa
authors.initials: S
authors.lastname: Shi
authors.forename: Fanghao
authors.initials: F
authors.lastname: Lu
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.forename: Changqing
authors.initials: C
authors.lastname: Xu
authors.forename: Lina
authors.initials: L
authors.lastname: Wang
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D001549:Benzamides / Q000627:therapeutic use*; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D006332:Cardiomegaly / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D003514:Cyclohexylamines / Q000627:therapeutic use*; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D017208:Rats, Wistar; D044169:Receptors, Calcium-Sensing / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D001549:Benzamides; D003514:Cyclohexylamines; C482333:N(1)-(4-chlorobenzoyl)-N(2)-(1-(1-naphthyl)ethyl)-1,2-diaminocyclohexane; D044169:Receptors, Calcium-Sensing; C546845:mTOR protein, rat; D058570:TOR Serine-Threonine Kinases; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D055372:AMP-Activated Protein Kinases