Blockade of NF-kappaB via p50 subunit disruption significantly attenuated myocardial hypertrophy in response to chronic angiotensin II infusion in mice without deteriorating cardiac function.
Does blockade of NF-kappaB via targeted disruption of the p50 subunit ameliorate ventricular hypertrophy in response to chronic infusion of angiotensin II in mice?
Blockade of NF-kappaB activation attenuates angiotensin II-induced myocardial hypertrophy without worsening cardiac function, suggesting a role for NF-kappaB in cardiac remodeling beyond inflammation.
OBJECTIVE: Nuclear factor (NF)-kappaB is a key transcription factor that regulates inflammatory processes. In the present study, we assessed the hypothesis that blockade of NF-kappaB may ameliorate ventricular hypertrophy in response to chronic infusion of angiotensin II. METHODS: Mice with targeted disruption of the p50 subunit of NF-kappaB (KO) were used to block the activation of NF-kappaB. Male KO and age-matched wild-type (WT) mice were chronically infused with angiotensin II at the rate of 0.2 (low dose) or 2 microg/kg/min (high dose) for 4 weeks. RESULTS: High- but not low-dose angiotensin II significantly increased systemic blood pressure and left ventricular weight in WT mice. In contrast, although the pressor response was slightly but significantly augmented, the hypertrophic effect of angiotensin II was significantly attenuated in KO mice. The attenuated hypertrophic responsiveness was confirmed histologically (cross-sectional area) and transcriptionally (atrial natriuretic peptide). Echocardiography revealed no evidence of cardiac dysfunction in angiotensin II-treated KO mice. Although phosphorylation of MAPKs, including ERK, JNK, or p38-MAPK, was not affected after 4 weeks of angiotensin II treatment in WT mice, phosphorylation of JNK was specifically abrogated in KO mice. Angiotensin II increased myocardial expression of proinflammatory cytokines and chemokines in WT mice, while expression of TNF-alpha and RANTES was paradoxically augmented in KO mice. CONCLUSION: Blockade of NF-kappaB activation attenuated myocardial hypertrophy without deteriorating cardiac function. NF-kappaB may play an important role in cardiac hypertrophy and remodeling besides promoting inflammation.
Kawano et al. (Wed,) conducted a other in Myocardial hypertrophy. Targeted disruption of the p50 subunit of NF-kappaB (KO) vs. Wild-type (WT) mice was evaluated on Ventricular hypertrophy (left ventricular weight and cross-sectional area). Blockade of NF-kappaB via p50 subunit disruption significantly attenuated myocardial hypertrophy in response to chronic angiotensin II infusion in mice without deteriorating cardiac function.