Characterization of human PDGFR-β-positive pericytes from IPF and non-IPF lungs

Abstract

Pericytes are key regulators of the microvasculature through their close interactions with the endothelium. However, pericytes play additional roles in tissue homeostasis and repair, in part by transitioning into myofibroblasts. Accumulation of myofibroblasts is a hallmark of fibrotic diseases such as idiopathic pulmonary fibrosis (IPF). To understand the contribution and role of pericytes in human lung fibrosis, we isolated these cells from non-IPF control and IPF lung tissues based on expression of platelet-derived growth factor receptor-β (PDGFR-β), a common marker of pericytes. When cultured in a specialized growth medium, PDGFR-β+ cells retain the morphology and marker profile typical of pericytes. We found that IPF pericytes migrated more rapidly and invaded a basement membrane matrix more readily than control pericytes. Exposure of cells to transforming growth factor-β, a major fibrosis-inducing cytokine, increased expression of α-smooth muscle actin and extracellular matrix genes in both control and IPF pericytes. Given that pericytes are uniquely positioned in vivo to respond to danger signals of both systemic and tissue origin, we stimulated human lung pericytes with agonists having pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs). Both control and IPF lung pericytes increased expression of proinflammatory chemokines in response to specific PAMPs and DAMPs released from necrotic cells. Our results suggest that control and IPF lung pericytes are poised to react to tissue damage, as well as microbial and fibrotic stimuli. However, IPF pericytes are primed for migration and matrix invasion, features that may contribute to the function of these cells in lung fibrosis.

Early time course of change in angiogenic proteins in human skeletal muscle and vascular cells with endurance training

“…In addition, pericytes were tagged by PDGFR‐β antibody and it was found that on average 88% of the NG2‐positive cells were also positive for PDGFR‐β. Previous studies have shown that PDGFR‐β is a valid marker of pericytes, for example, 40 and although a large fraction of the pericytes was indeed positive, a smaller fraction of the Ulex1 positive cells were also positive to this marker. Western blot of endothelial cells revealed presence of PECAM‐1 (CD31) and VE‐cadherin which were absent in the pericyte populations.…”

Are Liver Pericytes Just Precursors of Myofibroblasts in Hepatic Diseases? Insights from the Crosstalk between Perivascular and Inflammatory Cells in Liver Injury and Repair

“…Increased production of proinflammatory molecules by pericytes in the lungs of mice can be detected as early as six hours after the experimental administration of LPS [67]. Another reported characteristic of pericytes in other tissues is the ability to respond not only to PAMPs but also to DAMPs by secreting proinflammatory cytokines, as demonstrated in pericytes from the lungs of mice [67] and humans [68], and in human placental pericytes [69]. Secretion of inflammatory cytokines by HSCs after stimulation with DAMPs has not been demonstrated in vivo yet, even though an HSC cell line has been shown to exhibit greater expression of activation markers after stimulation with the DAMP high-mobility group box 1 (HMGB1) [70].…”

Pericytes as novel targets for HIV/SIV infection in the lung

“…Isolation and culture of PDGFRb + lung pericytes. Pericytes were isolated from macaque lungs, as previously described (36). Briefly, single-cell lung digests were plated and expanded in Pericyte Medium (ScienCell) to enrich for pericytes (2) and then underwent negative selection for endothelial, epithelial, and leukocyte markers, followed by positive selection for PDGFRb.…”

“…Briefly, single-cell lung digests were plated and expanded in Pericyte Medium (ScienCell) to enrich for pericytes (2) and then underwent negative selection for endothelial, epithelial, and leukocyte markers, followed by positive selection for PDGFRb. Previously isolated pericytes from HIVÀ human lungs (36) were cultured from frozen stocks. We confirmed absence of a-smooth muscle actin expression by RT-PCR and immunofluorescence.…”