Abstract Rationale Pericytes are mesenchymal stromal cells that support vascular stability and homeostasis. Following injury, pericytes can adopt proinflammatory phenotypes and differentiate into myofibroblasts, contributing to fibrotic remodeling. Both lung and skin function as barrier organs with constant exposure to inflammatory challenges. Prior RNA-seq analysis demonstrated significant downregulation of proinflammatory and matrix remodeling genes in skin relative to lung pericytes. We sought to determine if skin pericytes differ from lung pericytes at baseline and in response to proinflammatory and profibrotic stimulation. Methods Tissue from normal lungs and abdominal skin was mechanically disrupted and enzymatically digested, then cultured in specialized pericyte medium. Pericytes were enriched via selection for the pericyte marker PDGFRβ. To assess profibrotic response, pericytes were stimulated with transforming growth factor-β (TGFβ) for 24 and 48 hours. To model acute inflammation, pericytes were cultured and exposed to the pathogen-associated molecular pattern (PAMP) lipopolysaccharide (LPS) or to the damage-associated molecular pattern (DAMP) necrotic cell lysate for 6 hours. Cytoskeletal changes were evaluated via fluorescent phalloidin staining to assess stress fiber formation following stimulation of skin and lung pericytes with TGFβ. Results While our previous transcriptomics analysis suggested distinct differences between skin and lung pericytes in expression of proinflammatory genes at baseline, both mounted comparable responses to acute proinflammatory stimuli (LPS and necrotic cell lysate). In contrast, skin pericytes showed reduced transcriptional responses to TGFβ, with significantly lower induction of profibrotic markers (ACTA2, COL1A1, FN1) than lung pericytes. Interestingly, ACTA2, which encodes a key cytoskeletal protein upregulated in myofibroblastic cells, was also identified as a downregulated gene in skin pericytes by RT-PCR but was not a differentially expressed gene in the RNA-seq analysis. Preliminary cytoskeletal assays revealed that while exposure to TGFβ resulted in uniform actin stress fiber formation in lung pericytes, the response was more heterogeneous in skin pericytes. Conclusions Skin and lung pericytes display distinct baseline transcriptomics signatures, with skin pericytes demonstrating reduced activation of matrix-remodeling and proinflammatory pathways. While their responses to acute proinflammatory challenges are similar, skin pericytes appear less prone to TGFβ-driven profibrotic differentiation. These findings suggest that skin pericytes may be intrinsically less fibrogenic than lung pericytes, potentially reflecting tissue-specific adaptation to barrier functions and injury response. This abstract is funded by: NIH
Lafflam et al. (Fri,) studied this question.