State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China.
State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China.
Vet Microbiol. 2023 Jul;282:109748. doi: 10.1016/j.vetmic.2023.109748. Epub 2023 Apr 18.
Glaesserella parasuis is an important pathogen that causes fibrinous polyserositis, peritonitis and meningitis in pigs, leading to considerable economic losses to the swine industry worldwide. It is well established that the serine protease HtrA is closely associated with bacterial virulence, but the role of HtrA in G. parasuis pathogenesis remains largely unknown. To characterize the function of the htrA gene in G. parasuis, a ΔhtrA mutant was constructed. We found that the ΔhtrA mutant showed significant growth inhibition under heat shock and alkaline stress conditions, indicating HtrA is involved in stress tolerance and survival of G. parasuis. In addition, deletion of htrA gene resulted in decreased adherence to PIEC and PK-15 cells and increased phagocytic resistance to 3D4/2 macrophages, suggesting that htrA is essential for adherence of G. parasuis. Scanning electron microscopy revealed morphological surface changes of the ΔhtrA mutant, and transcription analysis confirmed that a number of adhesion-associated genes are downregulated, which corroborated the aforementioned phenomenon. Furthermore, G. parasuis HtrA induced a potent antibody response in piglets with Glässer's disease. These observations confirmed that the htrA gene is related to the survival and pathogenicity of G. parasuis.
副猪嗜血杆菌是一种重要的病原体，可引起猪的纤维蛋白性多发性浆膜炎、腹膜炎和脑膜炎，给全球养猪业造成了巨大的经济损失。丝氨酸蛋白酶 HtrA 与细菌毒力密切相关，这已得到充分证实，但 HtrA 在副猪嗜血杆菌发病机制中的作用在很大程度上仍不清楚。为了研究 htrA 基因在副猪嗜血杆菌中的功能，构建了Δ htrA 突变株。我们发现，Δ htrA 突变株在热激和碱性应激条件下表现出明显的生长抑制，表明 HtrA 参与副猪嗜血杆菌的应激耐受和存活。此外， htrA 基因缺失导致对 PIEC 和 PK-15 细胞的黏附能力降低，对 3D4/2 巨噬细胞的吞噬抵抗力增加，表明 htrA 对于副猪嗜血杆菌的黏附是必需的。扫描电子显微镜显示Δ htrA 突变株的表面形态发生了变化，转录分析证实了许多与黏附相关的基因下调，这与上述现象一致。此外，副猪嗜血杆菌 HtrA 在患有格拉泽氏病的仔猪中诱导了强烈的抗体反应。这些观察结果证实 htrA 基因与副猪嗜血杆菌的存活和致病性有关。
