Altered ubiquitin-proteasome signaling in right ventricular hypertrophy and failure

Viswanathan Rajagopalan, Mingming Zhao, Sushma Reddy, Giovanni Fajardo, Xuejun Wang, Shannamar Dewey, Aldrin V. Gomes, Daniel Bernstein

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Alterations in the ubiquitin-proteasome system (UPS) have been described in left ventricular hypertrophy and failure, although results have been inconsistent. The role of the UPS in right ventricular (RV) hypertrophy (RVH) and RV failure (RVF) is unknown. Given the greater percent increase in RV mass associated with RV afterload stress, as present in many congenital heart lesions, we hypothesized that alterations in the UPS could play an important role in RVH/RVF. UPS expression and activity were measured in the RV from mice with RVH/RVF secondary to pulmonary artery constriction (PAC). Epoxomicin and MG132 were used to inhibit the proteasome, and overexpression of the 11S PA28α subunit was used to activate the proteasome. PAC mice developed RVH (109.3% increase in RV weight to body weight), RV dilation with septal shift, RV dysfunction, and clinical RVF. Proteasomal function (26S β5 chymotrypsin-like activity) was decreased 26% (P < 0.05). Protein expression of 19S subunit Rpt5 (P < 0.05), UCHL1 deubiquitinase (P < 0.0001), and Smurf1 E3 ubiquitin ligase (P < 0.01) were increased, as were polyubiquitinated proteins (P < 0.05) and free-ubiquitins (P = 0.05). Pro-apoptotic Bax was increased (P < 0.0001), whereas anti-apoptotic Bcl-2 decreased (P < 0.05), resulting in a sixfold increase in the Bax/Bcl-2 ratio. Proteasomal inhibition did not accelerate RVF. However, proteasome enhancement by cardiacspecific proteasome overexpression partially improved survival. Proteasome activity is decreased in RVH/RVF, associated with upregulation of key UPS regulators and pro-apoptotic signaling. Enhancement of proteasome function partially attenuates RVF, suggesting that UPS dysfunction contributes to RVF.

Original languageEnglish (US)
Pages (from-to)H551-H562
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume305
Issue number4
DOIs
StatePublished - May 8 2013

Fingerprint

Right Ventricular Hypertrophy
Proteasome Endopeptidase Complex
Ubiquitin
Hypertrophy
Constriction
Pulmonary Artery
Ubiquitins
Right Ventricular Dysfunction
Ubiquitin-Protein Ligases
Chymotrypsin
Left Ventricular Hypertrophy
Dilatation
Proteins

Keywords

  • Cardiac hypertrophy
  • Heart failure
  • Proteasome
  • Right ventricle
  • Ubiquitin

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Altered ubiquitin-proteasome signaling in right ventricular hypertrophy and failure. / Rajagopalan, Viswanathan; Zhao, Mingming; Reddy, Sushma; Fajardo, Giovanni; Wang, Xuejun; Dewey, Shannamar; Gomes, Aldrin V.; Bernstein, Daniel.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 305, No. 4, 08.05.2013, p. H551-H562.

Research output: Contribution to journalArticle

Rajagopalan, Viswanathan ; Zhao, Mingming ; Reddy, Sushma ; Fajardo, Giovanni ; Wang, Xuejun ; Dewey, Shannamar ; Gomes, Aldrin V. ; Bernstein, Daniel. / Altered ubiquitin-proteasome signaling in right ventricular hypertrophy and failure. In: American Journal of Physiology - Heart and Circulatory Physiology. 2013 ; Vol. 305, No. 4. pp. H551-H562.
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