CRIF1 overexpression activates SIRT1/eNOS, protecting against Angiotensin II-induced atrial fibrillation and remodeling
Background
Atrial fibrillation (AF) is a prevalent arrhythmia characterized by myocardial injury, oxidative stress, and inflammatory remodeling, often leading to severe adverse outcomes, particularly in heart failure patients. Current therapies frequently fall short in targeting the underlying atrial remodeling processes. Mitochondrial protein CR6-interacting factor 1 (CRIF1) is known to regulate cardiomyocyte homeostasis, but its specific role and therapeutic potential in AF, especially concerning its impact on mitochondrial function and related pathways, have remained largely unexplored.
Study Design
Researchers established an AF model in C57BL/6 mice by subcutaneously infusing Angiotensin II (Ang II, 2.0 mg/kg/day) for 28 days. They evaluated CRIF1 expression and its functional effects in atrial tissue and Ang II-treated HL-1 cardiomyocytes using RT-qPCR, immunohistochemistry, ELISA, TUNEL, and DHE staining. To assess its protective role, CRIF1 was overexpressed, and its impact on the SIRT1/eNOS pathway, apoptosis, hypertrophy, inflammation, and oxidative stress was meticulously examined.
Results
Ang II infusion significantly promoted atrial remodeling and increased susceptibility to atrial fibrillation. Electrophysiological assessments revealed prolonged AF duration and increased AF inducibility in Ang II-treated mice compared to controls. Additionally, these mice exhibited elevated levels of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH), alongside enhanced expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). CRIF1 expression was markedly downregulated in the atrial tissue of AF mice and in Ang II-treated HL-1 cells. Overexpression of CRIF1 activated the SIRT1/eNOS pathway, significantly attenuating cardiomyocyte apoptosis and reducing Ang II-induced hypertrophy. Furthermore, CRIF1 suppressed the expression of inflammatory cytokines, including TNF-α, IL-1β, and IL-6, while diminishing intracellular reactive oxygen species accumulation. This restoration of antioxidant enzyme activity also led to increased nitric oxide (NO) production.
The protective effects of CRIF1 on apoptosis were largely dependent on
SIRT1signaling, highlighting a crucial mechanistic link.
Key Findings
- Angiotensin II infusion for 28 days induced atrial remodeling and increased AF susceptibility in C57BL/6 mice.
- CRIF1 expression was markedly downregulated in AF atrial tissue and Ang II-treated HL-1 cardiomyocytes.
- CRIF1 overexpression activated the
SIRT1/eNOSsignaling pathway. - CRIF1 attenuated cardiomyocyte apoptosis and reduced Ang II-induced hypertrophy.
- CRIF1 suppressed inflammatory cytokines (
TNF-α,IL-1β,IL-6) and diminished intracellular reactive oxygen species.
Why It Matters
This research positions CRIF1 as a critical protective factor and a novel therapeutic target for Ang II-induced atrial remodeling and AF. By activating the SIRT1/eNOS pathway and mitigating oxidative stress, inflammation, and hypertrophy, CRIF1 offers a multi-faceted approach to addressing the complex pathology of AF. For peptide users and biohackers, this highlights the potential of mitochondrial-targeted interventions, suggesting future research could explore compounds that modulate CRIF1 or its downstream SIRT1 pathway. While this is a preclinical animal study, it provides a strong mechanistic foundation, indicating that strategies to enhance CRIF1 activity could eventually lead to new pharmacological interventions or adjunctive therapies to prevent or treat AF, moving beyond current standard-of-care limitations.
atrial-fibrillation
crif1
sirt1
enos
oxidative-stress
inflammation