Identification of Novel Fibrosis Modifiers by In Vivo siRNA Silencing

Area of Science:

• Biomedical research
• Molecular biology
• Pathophysiology

Background:

• Fibrotic diseases cause 45% of deaths globally, necessitating a deeper understanding of their mechanisms.
• Myofibroblasts and their progenitors play a key role in tissue fibrosis development.
• Identifying novel fibrosis modifiers is crucial for developing effective treatments.

Purpose of the Study:

• To identify novel genes that modify tissue fibrosis.
• To investigate the role of myofibroblast-expressed genes in fibrogenesis.
• To validate these genes as potential therapeutic targets in vivo.

Main Methods:

• Utilized RNA silencing in vivo using small interfering RNA (siRNA)-formulated lipid nanoparticles.
• Targeted genes upregulated during liver and kidney fibrosis in mice.
• Induced liver fibrosis using carbon tetrachloride in a mouse model.

Main Results:

• Identified five genes (Egr2, Atp1a2, Fkbp10, Fstl1, Has2) that modify fibrogenesis upon silencing.
• Silencing these genes reduced Col1a1 mRNA levels and collagen accumulation in the liver.
• Egr2 silencing demonstrated the most significant effects in vivo and in human fibroblasts, reducing fibrogenic gene expression.

Conclusions:

• The study provides the first targeted siRNA assay to identify novel fibrosis modifiers in vivo.
• Egr2, Atp1a2, and Fkbp10 were functionally validated in fibrosis in vivo for the first time.
• These findings advance the understanding of fibrogenic pathways and offer potential therapeutic targets for fibrotic diseases.