Aim: Differentiation of cardiac fibroblasts (Fb) into myofibroblasts (MyoFb) is responsible for connective tissue buildup in myocardial remodeling. We examined reversibility of MyoFb differentiation. Methods and Results: Adult rat cardiac Fb were cultured on a plastic substratum providing mechanical stress, with conditions to obtain different Fb phenotypes. Fb spontaneously differentiated to proliferating MyoFb (p-MyoFb) with stress fiber formation decorated with alpha-smooth muscle actin (-SMA). Transforming growth factor-1 (TGF-1) promoted terminal differentiation into -SMA positive MyoFb showing near absence of proliferation i.e. non-p-MyoFb (2-fold increase in cell number after 12 days vs 11-fold for p-MyoFb). SD-208, a TGF--receptor-I kinase blocker, inhibited p-MyoFb differentiation as shown by stress fiber absence, low levels of -SMA protein expression, and high levels of proliferation (32-fold increase after 12 days). Fb seeded in collagen matrices induced no contraction, whereas p-MyoFb and non-p-MyoFb induced 2.5- and 4-fold contraction. Fb produced low levels of collagen and secreted high levels of IL-10. Non-p-MyoFb showed high collagen production and high MCP-1 and TIMP-1 secretion. Transcriptome analysis indicated differential gene expression between all phenotypes. Dedifferentiation of p-MyoFb, but not of non-p-MyoFb, was induced by SD-208 despite maintained stress, shown by stress fiber de-polymerization in 30% of p-MyoFb vs in 8% of non-p-MyoFb. Stress fiber de-polymerization could be induced by mechanical strain release in p-MyoFb and non-p-MyoFb (2 day culture in unrestrained 3-D collagen matrices). Only p-MyoFb showed true dedifferentiation after long-term 3-D culture. Conclusions: Both reduction in mechanical strain and TGF--receptor-I kinase inhibition can reverse p-MyoFb differentiation but not in non-p-MyoFb.
Reversible and irreversible differentiation of cardiac fibroblasts.
Sex, Specimen part
View SamplesWe used microarrays to compare gene expression across different murine tissues.
Mice deficient in the respiratory chain gene Cox6a2 are protected against high-fat diet-induced obesity and insulin resistance.
Sex, Specimen part
View SamplesTranscriptional profiling of 6-day-old seedlings of Arabidopsis wild type control and mutants is performed using Affymetrix IVT Arabidopsis ATH1 Genome Array.
Interactive and noninteractive roles of histone H2B monoubiquitination and H3K36 methylation in the regulation of active gene transcription and control of plant growth and development.
Age, Specimen part
View SamplesTranscription profiling of Arabidopsis mutant ron1-1 vs the wild type Ler
The RON1/FRY1/SAL1 gene is required for leaf morphogenesis and venation patterning in Arabidopsis.
Specimen part
View Samples