The expression of GapA and CrmA correlates with the Mycoplasma gallisepticum in vitro infection process in chicken TOCs

Abstract

Mycoplasma (M.) gallisepticum is the most pathogenic mycoplasma species in poultry. Infections cause mild to severe clinical symptoms associated with respiratory epithelial lesion development. Adherence, biofilm formation, and cell invasion of M. gallisepticum contribute to successful infection, immune evasion, and survival within the host. The important M. gallisepticum membrane-bound proteins, GapA and CrmA, are key factors for host cell interaction and the bacterial life-cycle, including its gliding motility, although their precise role in the individual infection step is not yet fully understood. In this study, we investigated the correlation between the host–pathogen interaction and the GapA/CrmA expression in an environment that represents the natural host’s multicellular compartment. We used an in vitro tracheal organ culture (TOC) model, allowing the investigation of the M. gallisepticum variants, Rlow, RCL1, RCL2, and Rhigh, under standardised conditions. In this regard, we examined the bacterial adherence, motility and colonisation pattern, host lesion development and alterations of mucociliary clearance. Compared to low virulent RCL2 and Rhigh, the high virulent Rlow and RCL1 were more efficient in adhering to TOCs and epithelium colonisation, including faster movement from the cilia tips to the apical membrane and subsequent cell invasion. RCL2 and Rhigh showed a more localised invasion pattern, accompanied by significantly fewer lesions than Rlow and RCL1. Unrelated to virulence, comparable mucus production was observed in all M. gallisepticum infected TOCs. Overall, the present study demonstrates the role of GapA/CrmA in virulence factors from adherence to colonisation, as well as the onset and severity of lesion development in the tracheal epithelium.

Unmasking the dynamics of Mycoplasma gallisepticum: deciphering HD11 macrophage polarization for innovative infection control strategies

“…This finding is consistent with previous reports by Cui et al (2021) , which demonstrated that Avian Tembusu virus ( TMUV ) infection induced alterations in HD11 cell morphology. In the tracheal organ culture ( TOC ) model, the expression of MG virulence genes gapA/crmA increased with infection time in the presence of different MG virulence level ( Ruger et al, 2022 ). Here, we observed that as the duration of MG infection increased, the morphology of MG-infected HD11 cells changed more significantly compared to the control group, accompanied by a gradual increase in MG virulence gene pMGA1.2 expression and copy numbers ( Figure 1 ).…”

In Vitro Investigation of the Interaction of Avian Metapneumovirus and Newcastle Disease Virus with Turkey Respiratory and Reproductive Tissue

“…A reduction in ciliary activity is a common consequence of pathogen-host interactions at the epithelial surfaces associated with several respiratory viruses [55][56][57][58]. Ciliary movement is part of the mucociliary clearance in the trachea, a key defence mechanism against invading respiratory pathogens and inhaled molecules [59].…”

Drug sensitivity and genome-wide analysis of two strains of Mycoplasma gallisepticum with different biofilm intensity

“…It helps them survive under pressure ( Fisunov et al, 2022 ). GapA is an essential protein for MG host cell adhesion and virulence and may be involved in biofilm formation ( Goh et al, 1998 ; Ruger et al, 2022 ). Quorum-sensing phenomenon (QS) is interdependent with biofilm formation, and rpoS is considered the major positive modulator of QS response.…”