Development of conditional-siRNA programmable riboswitch for targeting adverse cardiac remodeling

Area of Science:

• Biomedical Engineering
• Molecular Biology
• Cardiovascular Research

Background:

• Heart failure (HF) presents a significant healthcare challenge, necessitating innovative therapies targeting pathological cardiac hypertrophy.
• Current treatments lack specificity, highlighting the need for approaches that can selectively inhibit disease-causing genes within affected cells.

Purpose of the Study:

• To develop and validate novel conditional-siRNA (Cond-siRNA) constructs for targeted gene silencing in cardiomyocytes.
• To demonstrate the cell-specific activation of Cond-siRNA by disease biomarkers and its efficacy in reducing cardiac hypertrophy.

Main Methods:

• Design of a Cond-siRNA activated by Nppa mRNA, a biomarker upregulated in stressed cardiomyocytes.
• Utilized neonatal rat ventricular myocytes (NRVMs), H9c2 cells, and a heart-on-a-chip model subjected to phenylephrine (PE) or pressure overload (PO).
• Assessed calcineurin (CaN) gene silencing, protein levels, NFATc1 translocation, and cardiomyocyte hypertrophy.

Main Results:

• Cond-siRNA demonstrated minimal baseline activity but selectively silenced CaN upon Nppa mRNA induction under PE or PO stress.
• Specificity was confirmed in non-cardiomyocyte cells lacking Nppa expression.
• Reduced CaN levels and NFATc1 nuclear translocation correlated with decreased cardiomyocyte hypertrophy.

Conclusions:

• Conditional-siRNA represents a viable strategy for targeted gene inhibition in pathological hypertrophy.
• This technology offers a proof-of-concept for developing novel, cell-specific therapies for heart failure.
• The Nppa-activated Cond-siRNA effectively mitigated cardiac hypertrophy in preclinical models.