Echinatin attenuates LPS-induced mastitis by suppressing IL-17RA and MAPK/NF-κB signaling

Mastitis severely impairs milk yield and quality, as well as the health and productivity of dairy animals. Although antibiotics are the primary therapeutic option, their associated side effects drive the search for safer alternatives from botanical sources. Echinatin (Ech), a natural chalcone with known anti-inflammatory properties, has not been evaluated for its efficacy against mastitis. This study aimed to investigate the anti-inflammatory effects and underlying mechanisms of Ech using lipopolysaccharide (LPS)-induced bovine mammary epithelial cells (BMECs) and a mouse mastitis model.

The results demonstrated that Ech exhibited an anti-inflammatory effect by reducing the levels of inflammatory factors (tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and IL-17A) and decreasing protein levels of inflammatory mediators (cyclooxygenase-2 (COX2), and inducible nitric oxide synthase (iNOS)) in vitro and in vivo. Mechanistically, RNA-seq analysis identified an association with the IL-17 A receptor (IL-17RA) signaling following Ech intervention, which was subsequently validated by western blot showing that Ech suppressed the activation of both IL-17RA and the downstream MAPK/NF-κB pathways. Furthermore, in a recombine IL-17A (rIL-17A)-induced inflammatory model in BMECs, Ech attenuated the exacerbated inflammatory response by restraining IL-17RA and the downstream MAPK/NF-κB activation. Importantly, blocking IL-17RA signaling abolished the anti-inflammatory and pathway-inhibitory effects of Ech. Collectively, these results demonstrate a vital role of IL-17RA and MAPK/NF-κB pathway for Ech-mediated protection against mammary gland inflammation.

Our findings reveal that Ech attenuates LPS‑induced inflammation in BMECs and a mouse model of mastitis by suppressing IL-17RA signaling and thereby inactivating the MAPK/NF-κB pathway, offering new insights for optimizing preventive strategies against mastitis in dairy cows.