Abstract：
Porcine infectious pleuropneumonia (PCP) is a severe disease of porcine caused by Actinobacillus pleuropneumoniae (APP). The spread of PCP remains a threat to the porcine farms and has been known to cause severe economic losses. The cAMP receptor protein (CRP) serves as a pivotal player in helping bacteria adapt to shifts in their environment, particularly when facing the challenges posed by bacterial infections. In this study, we investigated the role of CRP in APP. Our results revealed that crp mutant (Δcrp) strains were more sensitive to acidic and osmotic stress resistance and had lower biofilm formation ability than wild-type (WT) strains. Furthermore, the Δcrp strains showed deficiencies in anti-phagocytosis, adhesion, and invasion upon interaction with host cells. Mice infected with the Δcrp strains demonstrated reduced bacterial loads in their lungs compared to those infected with the WT strains. This study reveals the pivotal role of crp gene expression in regulating pleuropneumonia growth, stress resistance, iron utilization, biofilm formation, phagocytosis, adhesion, invasion and colonization. Our discoveries offer novel perspectives on understanding the development and progression of APP infections.
摘要：
猪传染性胸膜肺炎(PCP)是由猪胸膜肺炎放线杆菌(APP)引起的严重疾病。PCP的传播仍然是对猪场的威胁，并且已知会造成严重的经济损失。cAMP受体蛋白（CRP）是帮助细菌适应环境变化的关键角色，特别是在面对细菌感染带来的挑战时。在这项研究中,我们研究了CRP在APP中的作用。我们的结果表明，crp突变体（Δcrp）菌株对酸性和渗透胁迫抗性更敏感，并且比野生型（WT）菌株具有更低的生物膜形成能力。此外，Δcrp菌株表现出抗吞噬作用的缺陷，附着力,和与宿主细胞相互作用时的侵袭。与用WT菌株感染的小鼠相比,用Δcrp菌株感染的小鼠在其肺中显示出减少的细菌负荷。这项研究揭示了crp基因表达在调节胸膜肺炎生长中的关键作用，抗应力，铁的利用，生物膜的形成，吞噬作用,附着力,入侵和殖民。我们的发现为理解APP感染的发展和进展提供了新的视角。
