Piezo1 selectively enhances TGF-β1-induced IgA class switching by B cells

Piezo1 is a mechanosensitive cationic channel that regulates Ca²⁺ influx, gene transcription, and cell migration. Recent studies suggest that Piezo1 affects regulatory T cells differentiation and is critical in B cell responses to membrane-presented antigens. However, the role of Piezo1 in B cells function is not completely elucidated. This study investigated the role of Piezo1 in IgA class switching and Ab production by mouse B cells using qRT-PCR, flow cytometric analysis, and isotype-specific ELISA. The Piezo1 agonist Yoda1 selectively upregulated TGF-β1-induced germline α transcripts (GLTα) /post-switch α transcripts (GLTα) expression, surface IgA expression, and IgA production. Conversely, the Piezo1 inhibitor OB-1 reduced IgA class switching. TGF-β1-induced IgA class switching and IgA production decreased in Piezo1 knockdown B cells. Additionally, Piezo1 enhanced TGF-β1-induced Smad3 phosphorylation. These results demonstrate that Piezo1 selectively enhances TGF-β1-induced IgA class switching via Smad3 phosphorylation, leading to IgA production in B cells.