Cellular re- and de-programming by microenvironmental memory: why short TGF-β1 pulses can have long effects

Area of Science:

• Cell Biology
• Regenerative Medicine
• Biochemistry

Background:

• Fibrosis, characterized by excessive collagen accumulation by myofibroblasts, hinders regenerative medicine.
• Transforming growth factor (TGF)-β1 is a key mediator, driving fibroblast differentiation into myofibroblasts.
• The kinetics of cellular responses to growth factor pulses remain poorly understood.

Purpose of the Study:

• To investigate the impact of short TGF-β1 pulses on the induction and maintenance of the myofibroblast phenotype.
• To understand the cellular response kinetics following growth factor stimulation.

Main Methods:

• Exposure of fibroblasts to short pulses of TGF-β1.
• Analysis of fibrogenic gene transcription and collagen I secretion.
• Assessment of α-smooth muscle actin (α-SMA) presence.
• Evaluation of the role of extracellular matrix (ECM) in mediating cellular responses.

Main Results:

• A single 30-minute TGF-β1 pulse upregulated fibrogenic genes and increased collagen I secretion and α-SMA for 7 days.
• A second pulse extended these effects to 14 days.
• Deposited ECM could induce myofibroblast features in untreated fibroblasts, with efficacy dependent on ECM age.

Conclusions:

• Short TGF-β1 pulses induce long-lasting fibroblast changes via microenvironmental modifications, creating a feedback loop.
• The ECM may serve as a mid-term memory for pathobiochemical events, potentially erasable through matrix turnover.
• Findings inform the development of antifibrotic therapies by highlighting ECM-mediated memory effects.