Down-regulation of TUFM impairs host cell interaction and virulence by Paracoccidioides brasiliensis

Abstract

The genus Paracoccidioides consist of dimorphic fungi geographically limited to the subtropical regions of Latin America, which are responsible for causing deep systemic mycosis in humans. However, the molecular mechanisms by which Paracoccidioides spp. causes the disease remain poorly understood. Paracoccidioides spp. harbor genes that encode proteins involved in host cell interaction and mitochondrial function, which together are required for pathogenicity and mediate virulence. Previously, we identified TufM (previously known as EF-Tu) in Paracoccidioides brasiliensis (PbTufM) and suggested that it may be involved in the pathogenicity of this fungus. In this study, we examined the effects of downregulating PbTUFM using a silenced strain with a 55% reduction in PbTUFM expression obtained by antisense-RNA (aRNA) technology. Silencing PbTUFM yielded phenotypic differences, such as altered translation elongation, respiratory defects, increased sensitivity of yeast cells to reactive oxygen stress, survival after macrophage phagocytosis, and reduced interaction with pneumocytes. These results were associated with reduced virulence in Galleria mellonella and murine infection models, emphasizing the importance of PbTufM in the full virulence of P. brasiliensis and its potential as a target for antifungal agents against paracoccidioidomycosis.

Molecular characterization of siderophore biosynthesis in Paracoccidioides brasiliensis

“…The ethical reasons linked to vertebrate models, as well as the high costs for animal management have propelled the examination of viable substitutes (Wilson-Sanders 2011 ). Several studies have demonstrated the use of Galleria mellonella larvae to characterize the infection process in pathogenic fungi, such as Histoplasma capsulatum , C. albicans , Cryptococcus neoformans and P. brasiliensis (Thomaz et al 2013 ; Vargas et al 2015 ; Bouklas et al 2015 ; Scorzoni et al 2015 ; Marcos et al 2019 ). However, G. mellonella is an animal that requires almost daily handling, as well as these insects are not sold worldwide (Jorjao et al 2018 ).…”

On the relationship between Pathogenic Potential and Infective Inoculum

“…Future studies may want to further investigate the mechanism underlying the unique dose-dependency, or independency, of H. capsulatum and P. lutzii infections in G. mellonella. The general dose-independent effect on survival could be the result of the slow and irregular growth of the microbe (11)(12)(13), or a damaging immune response that kills the host in response to few or many microbes (Table 1). In this regard, P.…”

Mitochondrial Protein Translation: Emerging Roles and Clinical Significance in Disease

“…Some studies have shown that EFTU also participates in the process of disease by regulating oxidative stress. Silencing TUFM in Paracoccidioides brasiliensis reportedly alters translation elongation, causes respiratory defects, and increases the sensitivity of yeast cells to reactive oxygen stress, indicating the involvement of TUFM in the pathogenicity of this fungus ( Marcos et al, 2019 ). Moreover, EFTU can physically interact with Xeroderma pigmentosum group D (XPD) protein, which is involved in mitochondrial oxidative DNA damage repair ( Liu et al, 2015 ).…”