Candida parapsilosis virulenciájának vizsgálata = Regulation, Function and Structure of Virulence Factors of Candida parapsilosis

A Candida parapsilosis mint humán opportunista kórokozó komoly egészségügyi problémát jelent világszerte. Ennek ellenére keveset tudunk a patogén virulencia faktorairól, illetve a kiváltott kórfolyamat immunulógiai hátteréről. Munkánk célja a gomba virulencia faktorainak megismerése illetve a gazda-patogén interakciók vizsgálata volt. A szekretált hidrolitikus enzimek potenciális virulencia faktorok lehetnek, aminek bizonyítására szekretált proteináz gének delécióját hajtottuk végre. Sikeresen hoztunk létre Sapp1 deficiens mutánsokat és bizonyítottuk, hogy a fehérjének szerepe van az emberi szérum komponensei elleni védelemben, a professzionális immunsejtek fagocitózis és gombaölő folyamatinak gátlásában. Kimutattuk továbbá, hogy a Sapp1 fehérje elvesztését a patogén más Sapp fehérjék túltermelésével kompenzálja. Bebizonyítottuk, hogy az extracelluláris lipázok képesek a humán dendritikus sejtek aktivációját csökkenteni a fagocitózis és a gombaölőképesség csökkentésével illetve különböző gyulladásos citokinek termelésének gátlásával, valamint azt hogy a zsírsav bioszintézisben szerepet játszó Ole1 fehérje jelentős szerepet játszik a gazda-patogén interakciókban. Kifejlesztettünk egy újszülött patkányokat alkalmazó in vivo fertőzési modellt, amelynek segítségével bizonyítottuk, hogy a szekretált lipázok mind a C. albicans mind a C. parapsilosis esetében fontos virulencia faktorok. | Candida parapsilosis typically is a commensal of human skin. However, when host immune defense is compromised or the normal microflora balance is disrupted, C. parapsilosis transforms itself into a pathogen. Candida-derived hidrolytic enzymes have been identified as potential virulence factor. Thus, the aim of our work was to assess the function of secreted hidrolytic enzymes in C. parapsilosis virulence and to determine the role that C. parapsilosis-derived lipase and proteinase play in the interaction with host immune cells. We have successfully generated a sapp1 minus strain and showed elevated activity of SAPP2 in both on mRNA and protein level in the mutant strain. Phagocytosis and killing assays showed increased level of intracellular pahgocytosis and killing in the case of the sapp1 minus strain, and the macrophage damage caused the mutant strain was lower compared to that of the wild type. Taken together, these data strongly suggest the involvement of sapp1p in virulence and pathogenicity of C. parapsilosis. Furthermore, our results show that DCs are activated by exposure to C. parapsilosis, as shown by increased phagocytosis, killing and proinflammatory protein secretion. Moreover, the results strongly suggest that C. parapsilosis derived lipase has a protective role during yeast:DC interactions, since lipase production in wt yeast cells decreased the phagocytic capacity and killing efficiency of host cells and downregulated the expression of host effector molecules

Candida auris az új "szupergomba"

A gombák által kiváltott fertőzések száma évek óta növekvő tendenciát mutat világszerte. Ezen megbetegedésekért nagy arányban a Candida nemzetség képviselői a felelősek, azonban a nemzetségen belül a fertőzést okozó fajok arányában változások figyelhetők meg az elmúlt években. Az egyik feltörekvő Candida faj a Candida auris, mely alig több mint 10 éves múltra tekint vissza, mégis a gomba ellenes szerekkel szembeni kiemelkedő arányú rezisztenciája, illetve klinikai környezetben való terjedése miatt kiemelt figyelemre tett szert. Ezen tulajdonságai miatt az antifungális rezisztencia kialakulásának, illetve hatásának vizsgálata C. auris esetében kiemelten fontos feladat

In vitro interactions of Candida parapsilosis wild type and lipase deficient mutants with human monocyte derived dendritic cells

<p>Abstract</p> <p>Background</p> <p><it>Candida parapsilosis </it>typically is a commensal of human skin. However, when host immune defense is compromised or the normal microflora balance is disrupted, <it>C. parapsilosis </it>transforms itself into an opportunistic pathogen. <it>Candida</it>-derived lipase has been identified as potential virulence factor. Even though cellular components of the innate immune response, such as dendritic cells, represent the first line of defense against invading pathogens, little is known about the interaction of these cells with invading <it>C. parapsilosis</it>. Thus, the aim of our study was to assess the function of dendritic cells in fighting <it>C. parapsilosis </it>and to determine the role that <it>C. parapsilosis</it>-derived lipase plays in the interaction with dendritic cells.</p> <p>Results</p> <p>Monocyte-derived immature and mature dendritic cells (iDCs and mDCs, respectively) co-cultured with live wild type or lipase deficient <it>C. parapsilosis </it>strains were studied to determine the phagocytic capacity and killing efficiency of host cells. We determined that both iDCs and mDCs efficiently phagocytosed and killed <it>C. parapsilosis</it>, furthermore our results show that the phagocytic and fungicidal activities of both iDCs and mDCs are more potent for lipase deficient compared to wild type yeast cells. In addition, the lipase deficient <it>C. parapsilosis </it>cells induce higher gene expression and protein secretion of proinflammatory cytokines and chemokines in both DC types relative to the effect of co-culture with wild type yeast cells.</p> <p>Conclusions</p> <p>Our results show that DCs are activated by exposure to <it>C. parapsilosis</it>, as shown by increased phagocytosis, killing and proinflammatory protein secretion. Moreover, these data strongly suggest that <it>C. parapsilosis </it>derived lipase has a protective role during yeast:DC interactions, since lipase production in wt yeast cells decreased the phagocytic capacity and killing efficiency of host cells and downregulated the expression of host effector molecules.</p

The effect of antifungal resistance development on the virulence of Candida species

In recent years, the relevance of diseases associated with fungal pathogens increased worldwide. Members of the Candida genus are responsible for the greatest number of fungal bloodstream infections every year. Epidemiological data consistently indicate a modest shift toward non-albicans species, albeit Candidaalbicans is still the most recognizable species within the genus. As a result, the number of clinically relevant pathogens has increased, and, despite their distinct pathogenicity features, the applicable antifungal agents remained the same. For bloodstream infections, only three classes of drugs are routinely used, namely polyenes, azoles and echinocandins. Antifungal resistance toward all three antifungal drug classes frequently occurs in clinical settings. Compared with the broad range of literature on virulence and antifungal resistance of Candida species separately, only a small portion of studies examined the effect of resistance on virulence. These studies found that resistance to polyenes and echinocandins concluded in significant decrease in the virulence in different Candida species. Meanwhile, in some cases, resistance to azole type antifungals resulted in increased virulence depending on the species and isolates. These findings underline the importance of studies aiming to dissect the connections of virulence and resistance in Candida species

Kinetic studies of Candida parapsilosis phagocytosis by macrophages and detection of intracellular survival mechanisms

Peer reviewedPublisher PD

Characterization and functional analysis of zinc trafficking in the human fungal pathogen Candida parapsilosis

The zinc restriction and zinc toxicity are part of host defence, called nutritional immunity. The crucial role of zinc homeostasis in microbial survival within a host is established, but little is known about these processes in the opportunistic human fungal pathogen Candida parapsilosis. Our in silico predictions suggested the presence of at least six potential zinc transporters (ZnTs) in C. parapsilosis-orthologues of ZRC1, ZRT3 and ZRT101-but an orthologue of PRA1 zincophore was not found. In addition, we detected a species-specific gene expansion of the novel ZnT ZRT2, as we identified three orthologue genes in the genome of C. parapsilosis. Based on predictions, we created homozygous mutant strains of the potential ZnTs and characterized them. Despite the apparent gene expansion of ZRT2 in C. parapsilosis, only CpZRT21 was essential for growth in a zinc-depleted acidic environment, in addition we found that CpZrc1 is essential for zinc detoxification and also protects the fungi against the elimination of murine macrophages. Significantly, we demonstrated that C. parapsilosis forms zincosomes in a Zrc1-independent manner and zinc detoxification is mediated by the vacuolar importer CpZrc1. Our study defines the functions of C. parapsilosis ZnTs, including a species-specific survival and zinc detoxification system