Sunny Kataria, PhD
University of Michigan
Targeted degradation of p300 reverses dermal fibroblast activation in systemic sclerosis
Fibrosis in systemic sclerosis (SSc) is driven by persistent activation of fibroblasts into collagen-producing myofibroblasts. The histone acetyltransferase p300 (EP300) is a key epigenetic regulator that integrates multiple fibrotic signaling to sustain profibrotic transcriptional programs in dermal fibroblasts, but therapeutic targeting of p300 in SSc fibrosis remains unexplored. We used, a p300-targeting PROTAC, to induce degradation of p300 in primary human dermal fibroblasts from healthy and SSc patients. Healthy fibroblasts were activated with TGFbeta, and constitutively activated fibroblasts were isolated using SSc tissue. Nanomolar concentration of PROTAC induced rapid and near-complete degradation of p300 and CBP in both activated healthy and SSc dermal fibroblasts. p300 degradation was accompanied by marked reductions in collagen I and α-smooth muscle actin protein levels, along with consistent ~30 to 60% suppression of key fibrotic and inflammatory transcripts (COL1A1, COL1A2, FN1, ACTA2, IL6) across donors. Loss of p300 significantly reduced histone H3 and H2B acetylation without detectable cytotoxicity, indicating epigenetic reprogramming. Our data demonstrates that targeted degradation of p300 is sufficient to reverse dermal fibroblast activation and fibrotic gene expression in SSc. p300 PROTACs represent a novel epigenetic strategy to therapeutically reprogram fibroblasts, with strong translational potential.
Fibrosis in systemic sclerosis (SSc) is driven by persistent activation of fibroblasts into collagen-producing myofibroblasts. The histone acetyltransferase p300 (EP300) is a key epigenetic regulator that integrates multiple fibrotic signaling to sustain profibrotic transcriptional programs in dermal fibroblasts, but therapeutic targeting of p300 in SSc fibrosis remains unexplored. We used, a p300-targeting PROTAC, to induce degradation of p300 in primary human dermal fibroblasts from healthy and SSc patients. Healthy fibroblasts were activated with TGFbeta, and constitutively activated fibroblasts were isolated using SSc tissue. Nanomolar concentration of PROTAC induced rapid and near-complete degradation of p300 and CBP in both activated healthy and SSc dermal fibroblasts. p300 degradation was accompanied by marked reductions in collagen I and α-smooth muscle actin protein levels, along with consistent ~30 to 60% suppression of key fibrotic and inflammatory transcripts (COL1A1, COL1A2, FN1, ACTA2, IL6) across donors. Loss of p300 significantly reduced histone H3 and H2B acetylation without detectable cytotoxicity, indicating epigenetic reprogramming. Our data demonstrates that targeted degradation of p300 is sufficient to reverse dermal fibroblast activation and fibrotic gene expression in SSc. p300 PROTACs represent a novel epigenetic strategy to therapeutically reprogram fibroblasts, with strong translational potential.
