Proteomic profile of TGF-β1 treated lung fibroblasts identifies novel markers of activated fibroblasts in the silica exposed rat lung

Abstract

We performed liquid chromatography-tandem mass spectrometry (LC-MS/MS) on control and TGF-β1-exposed rat lung fibroblasts to identify proteins differentially expressed between cell populations. A total of 1648 proteins were found to be differentially expressed in response to TGF-β1 treatment and 196 proteins were expressed at ≥ 1.2 fold relative to control. Guided by these results, we next determined whether similar changes in protein expression were detectable in the rat lung after chronic exposure to silica dust. Of the five proteins selected for further analysis, we found that levels of all proteins were markedly increased in the silica-exposed rat lung, including the proteins for the very low density lipoprotein receptor (VLDLR) and the transmembrane (type I) heparin sulfate proteoglycan called syndecan 2 (SDC2). Because VLDLR and SDC2 have not, to our knowledge, been previously linked to the pathobiology of silicosis, we next examined whether knockdown of either gene altered responses to TGF-β1 in MRC-5 lung fibroblasts. Interestingly, we found knockdown of either VLDLR or SDC2 dramatically reduced collagen production to TGF-β1, suggesting that both proteins might play a novel role in myofibroblast biology and pathogenesis of silica-induced pulmonary fibrosis. In summary, our findings suggest that performing LC-MS/MS on TGF-β1 stimulated lung fibroblasts can uncover novel molecular targets of activated myofibroblasts in silica-exposed lung.

RETRACTED: IL‐17A‐producing T cells exacerbate fine particulate matter‐induced lung inflammation and fibrosis by inhibiting PI3K/Akt/mTOR‐mediated autophagy

“…Moreover, we also found that PM2.5 promoted the secretion of IL‐17A, activated the TGF signalling pathway and promoted EMT in bronchial epithelial cells, thereby leading to pulmonary fibrosis. In agreement with our results, previous reports have also found IL‐17A to be closely related with pulmonary fibrosis‐related signalling pathways 27‐32 . Moreover, the role of TGF‐β is well known in migration, invasion as well as hyperplastic changes of lung fibroblasts in pulmonary fibrosis 28,33,34 .…”

Pulmonary Silicosis Alters MicroRNA Expression in Rat Lung and miR-411-3p Exerts Anti-fibrotic Effects by Inhibiting MRTF-A/SRF Signaling

“…The differentiation of fibroblasts to myofibroblasts can be induced by TGF-b1 and is associated with excessive extracellular matrix deposition. 14,15 It has been well documented that serum response factor (SRF) and its transcription cofactor, myocardin-related transcription factor A (MRTF-A), can regulate the expression of a-SMA at the transcriptional level, 16 and they have also been reported to promote the synthesis of collagen type I (Col I) and play a key role in pulmonary fibrosis. 17 In the present study, we found that many of the miRNAs differentially expressed in pulmonary fibrosis had effects on myofibroblast differentiation and the production of extracellular matrix in vitro.…”

The role of macrophage-derived TGF-β1 on SiO2-induced pulmonary fibrosis: A review

“…The sources of myofibroblasts should be investigated more in detail. According to the pedigree tracing experiment, many kinds of cells in interstitial lung tissue differentiate into myofibroblasts, and their main source is the fibroblast-derived myofibroblasts (Na et al, 2019; Sakai and Tager, 2013). The expression of type I collagen and α-SMA can be detected in fibroblasts when co-cultured with silica-exposed macrophages.…”