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Updated: May 28, 2026
09:53
In Vivo Nanovector Delivery of a Heart-specific MicroRNA-sponge
Published on: June 15, 2018
Cardiac insulin resistance and microRNA modulators
Lakshmi Pulakat1, Annayya R Aroor, Rukhsana Gul
1Department of Internal Medicine, School of Medicine, University of Missouri, Columbia, MO 65212, USA.
Experimental Diabetes Research
|October 7, 2011
Summary
Chronic alcohol consumption worsens cardiac insulin resistance by inhibiting mTOR/S6K1 signaling, potentially exacerbating cardiorenal metabolic syndrome (CRS) and heart failure. Protective feedback mechanisms in obese rats suggest pathways to mitigate these effects.
Area of Science:
- Cardiovascular Biology
- Metabolic Disorders
- Molecular Cardiology
Background:
- Cardiac insulin resistance (CIR) is linked to obesity and cardiorenal metabolic syndrome (CRS), often worsened by alcohol.
- Overnutrition activates mTOR/S6K1 signaling, while alcohol inhibits it in cardiac tissue.
- Excessive mTOR/S6K1 activation causes insulin resistance but can offer cardioprotection via AT2R.
Purpose of the Study:
- To investigate the role of mTOR/S6K1 signaling in cardiac insulin resistance.
- To explore the impact of chronic alcohol consumption on cardiac metabolic pathways.
- To understand regulatory mechanisms in obese Zucker rats with CRS.
Main Methods:
- Utilized the Zucker obese (ZO) rat model for cardiorenal metabolic syndrome (CRS).
- Examined mammalian target of rapamycin (mTOR)/p70 S6 kinase (S6K1) signaling pathways in cardiac tissue.
- Analyzed microRNA profiles and insulin receptor substrate (IRS) phosphorylation.
Main Results:
- In ZO rats, protective feedback loops involving mTOR↔AT2R signaling and microRNAs regulate S6K1 activation, potentially mitigating heart failure.
- Alcohol consumption inhibits cardiac mTOR/S6K1, downregulates insulin receptors and mir-200 family, and upregulates mir-212.
- These alcohol-induced changes may worsen CRS-related cardiomyopathy.
Conclusions:
- Cardiac insulin resistance and CRS are complex metabolic disorders influenced by diet and alcohol.
- mTOR/S6K1 signaling and associated microRNAs play a critical role in cardiac adaptation and pathology.
- Alcohol exacerbates cardiac dysfunction in CRS by disrupting key metabolic and signaling pathways.
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