title: Disruption of endothelial cell mitochondrial bioenergetics in lambs with increased pulmonary blood flow.
abstract: OBJECTIVE
  The mitochondrial dysfunction in our lamb model of congenital heart disease with increased pulmonary blood flow (PBF) (Shunt) is associated with disrupted carnitine metabolism. Our recent studies have also shown that asymmetric dimethylarginine (ADMA) levels are increased in Shunt lambs and ADMA increases the nitration of mitochondrial proteins in lamb pulmonary arterial endothelial cells (PAEC) in a nitric oxide synthase (NOS)-dependent manner. Thus, we determined whether there was a mechanistic link between endothelial nitric oxide synthase (eNOS), ADMA, and the disruption of carnitine homeostasis in PAEC.
  
  
  RESULTS
  Exposure of PAEC to ADMA induced the redistribution of eNOS to the mitochondria, resulting in an increase in carnitine acetyl transferase (CrAT) nitration and decreased CrAT activity. The resulting increase in acyl-carnitine levels resulted in mitochondrial dysfunction and the disruption of mitochondrial bioenergetics. Since the addition of L-arginine prevented these pathologic changes, we examined the effect of L-arginine supplementation on carnitine homeostasis, mitochondrial function, and nitric oxide (NO) signaling in Shunt lambs. We found that the treatment of Shunt lambs with L-arginine prevented the ADMA-mediated mitochondrial redistribution of eNOS, the nitration-mediated inhibition of CrAT, and maintained carnitine homeostasis. In turn, adenosine-5'-triphosphate levels and eNOS/heat shock protein 90 interactions were preserved, and this decreased NOS uncoupling and enhanced NO generation.
  
  
  METHODS
  Our data link alterations in cellular L-arginine metabolism with the disruption of mitochondrial bioenergetics and implicate altered carnitine homeostasis as a key player in this process.
  
  
  CONCLUSIONS
  L-arginine supplementation may be a useful therapy to prevent the mitochondrial dysfunction involved in the pulmonary vascular alterations secondary to increased PBF.
authors.affiliation: Pulmonary Disease Program, Vascular Biology Center, Georgia Health Sciences University, Augusta, GA 30912, USA. xsun@georgiahealth.edu
authors.forename: Xutong
authors.initials: X
authors.lastname: Sun
authors.forename: Shruti
authors.initials: S
authors.lastname: Sharma
authors.forename: Sohrab
authors.initials: S
authors.lastname: Fratz
authors.forename: Sanjiv
authors.initials: S
authors.lastname: Kumar
authors.forename: Ruslan
authors.initials: R
authors.lastname: Rafikov
authors.forename: Saurabh
authors.initials: S
authors.lastname: Aggarwal
authors.forename: Olga
authors.initials: O
authors.lastname: Rafikova
authors.forename: Qing
authors.initials: Q
authors.lastname: Lu
authors.forename: Tantiana
authors.initials: T
authors.lastname: Burns
authors.forename: Sridevi
authors.initials: S
authors.lastname: Dasarathy
authors.forename: Johnny
authors.initials: J
authors.lastname: Wright
authors.forename: Christian
authors.initials: C
authors.lastname: Schreiber
authors.forename: Monique
authors.initials: M
authors.lastname: Radman
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Fineman
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Black
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D002331:Carnitine / Q000378:metabolism; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006330:Heart Defects, Congenital / Q000150:complications; D006706:Homeostasis / Q000187:drug effects; D006976:Hypertension, Pulmonary / Q000209:etiology; D008168:Lung / Q000098:blood supply* / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D011652:Pulmonary Circulation / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D012756:Sheep; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D009569:Nitric Oxide; C018524:N,N-dimethylarginine; D000255:Adenosine Triphosphate; D001120:Arginine; D052250:Nitric Oxide Synthase Type III; D002331:Carnitine