Bioinsecticide PA1b alleviates lipopolysaccharide-induced inflammation and impairment of bovine mammary epithelial cells

Pea Albumin 1, subunit b (PA1b) is a 37 amino acid peptide. It was extracted from pea seeds and showed significant insecticidal activity against certain insects, such as the mosquitoes Culex pipiens and Aedes aegyptii, cereal weevils (genus Sitophilus), and certain species of aphids. Considering that pea seeds are regularly consumed by humans and mammals, PA1b is assumed to be a promising bioinsecticide with no allergenicity or toxicity to hosts. To clarify this aspect, PA1b was applied to bovine mammary epithelial cells challenged with lipopolysaccharide (LPS). The results revealed that LPS induced inflammatory cytokine tumor necrosis factor-alpha (TNF alpha), interleukin 6 (IL6) and monocyte chemoattractant protein 1 (MCP-1) secretion, while PA1b depressed these cytokines release via inhibiting NF-kappa B signaling activation. In addition, PA1b protected mammary epithelial cells from impairment caused by LPS, because it reduced cell membrane permeability and subsequently reconstructed mammary epithelial cell viability. Moreover, it inhibited cell apoptosis accompanied with alleviated oxidative stress. Furthermore, PA1b prevented opening of mitochondrial permeability transition pores, in turn upregulated mitochondrial membrane potential and ATP production. Therefore, PA1b improved mitochondrial function, which contributed to re-construction of mammary epithelial cell viability. In conclusion, PA1b alleviates LPS-induced inflammation of bovine mammary epithelial cells via inhibiting NF-kappa B signaling activation and protects bovine mammary epithelial cells by improving mitochondrial function. PA1b is a good therapeutic survival factor for mammary epithelial cells.