Ubiquitin-Related Proteostatic Programs in Cycling Fibroblast-Lineage Remodeling After Myocardial Ischemic Injury: A...

Area of Science:

• Cardiovascular Biology
• Cellular Biology
• Molecular Medicine

Background:

• Myocardial ischemia and reperfusion (I/R) trigger complex injury-repair processes in the heart.
• Cardiac fibroblasts are crucial for scar formation during ventricular remodeling.
• Fibroblast populations exhibit dynamic, region-specific states revealed by single-cell and spatial transcriptomics.

Purpose of the Study:

• To review and integrate evidence on cardiac fibroblast biology in myocardial I/R.
• To explore the role of ubiquitin-proteasome system (UPS) and cell-cycle regulation in fibroblast remodeling.
• To propose a framework linking fibroblast lineage, injury context, and proteostatic dependencies.

Main Methods:

• Narrative review integrating direct I/R studies with evidence from permanent infarction, human infarction, and in vitro systems.
• Analysis of fibroblast-specific ubiquitin biology, including deubiquitination axes (e.g., HSP47-USP10-SMAD4).
• Examination of cell-cycle regulation (e.g., CCNB1) and fibroblast atlases.

Main Results:

• A direct I/R study identified an HSP47-USP10-SMAD4 deubiquitination axis in fibroblasts.
• Most UPS mechanisms in fibroblasts are derived from permanent infarction or non-ischemic models.
• CCNB1-associated, G2/M-enriched fibroblast states may increase proteostatic demands post-ischemia.

Conclusions:

• Fibroblast lineage, injury model, niche, and temporal window may jointly define proteostatic dependencies during post-ischemic remodeling.
• RNA signatures for ubiquitin are proxies; protein-level and spatial analyses are needed.
• Further validation in human infarct tissue is required to resolve proposed relationships.