PTPN2 alleviates Silicotic pulmonary fibrosis by inhibiting senescence of type II alveolar epithelial cells via retinol metabolism regulated by ALDH1A2.

Overexpression of PTPN2 significantly reduced the degree of pulmonary fibrosis in silicosis model mice.

• Effects were evaluated using microcomputed tomography, histological examination, and western blot analysis.
• Transcriptome sequencing was used to assess pathway-level changes.
• The protective effect was observed both in vitro and in vivo.

Alveolar epithelial cell-specific knockout of PTPN2 exacerbated pulmonary fibrosis in silicosis.

• Cell-type specific knockout was used to confirm the role of PTPN2 in alveolar epithelial cells.
• The abstract refers to these cells as 'alveolar endothelial cells' but the paper's focus is on type II alveolar epithelial cells.
• This finding contrasts with the protective effect seen with PTPN2 overexpression.

PTPN2 overexpression upregulated retinol metabolism signaling pathway-related molecules ALDH1A2, RDH10, and DHRS3.

• These findings were observed both in vitro and in vivo.
• ALDH1A2 was identified as a key regulator of the retinol metabolism pathway through which PTPN2 acts.
• Western blot analysis was among the methods used to assess protein expression.

PTPN2 overexpression reversed expression of TGF-β1 signaling pathway components and reduced Smad2/3 phosphorylation.

• TGF-β1, TGF-βR1, and TGF-βR2 expression were all reversed by PTPN2 overexpression.
• Phosphorylation of Smad2/3 was downregulated following PTPN2 overexpression.
• These changes were confirmed both in vitro and in vivo.

PTPN2 overexpression downregulated the expression of senescence-associated factors in type II alveolar epithelial cells.

• Senescence-associated factors assessed included β-galactosidase, p-p53, p21, and p16.
• Results were confirmed both in vitro and in vivo.
• Inhibition of type II alveolar epithelial cell senescence was identified as a key mechanism by which PTPN2 alleviates fibrosis.

PTPN2 ameliorated silicotic pulmonary fibrosis by regulating key enzymes in retinol metabolism and downregulating the TGF-β1 signaling pathway.

• The study used transcriptome sequencing to identify retinol metabolism as a relevant signaling pathway.
• The mechanism links PTPN2 activity to ALDH1A2-regulated retinol metabolism, which in turn modulates TGF-β1 signaling and cellular senescence.
• Both in vitro and in vivo experimental approaches were used to confirm these mechanistic findings.