Navegando por Palavras-chave "Histidine Kinases"

Agora exibindo 1 - 1 de 1
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Estudo do papel da Histidina quinase reguladora do dimorfismo (DRK1) do fungo patogênico Paracoccidioides brasiliensis
    (Universidade Federal de São Paulo (UNIFESP), 2021) Navarro, Marina Valente [UNIFESP]; Batista, Wagner Luiz [UNIFESP]; Universidade Federal de São Paulo
    Thermal dimorphic fungi of Paracoccidioides genus are the causative agents of paracoccidioidomycosis (PCM), a systemic endemic disease in Latin America with high incidence in Brazil. This pathogen presents as infective mycelium at 25°C in the soil, reverting to its pathogenic form when inhaled by mammalian host (37°C). This ability to switch from mycelium to yeast form is essential to disease development. Among dimorphic fungus species, dimorphism regulating histidine kinase (Drk1) plays an essential role to morphological transition. Histidine kinases (HK) are very important as virulence and cellular survival regulators. These kinases are present in bacteria and fungi, but absent in mammalian cells. This evidence suggests that HKs are interesting pharmacological targets to fungal diseases. Recently, our group characterized P. brasiliensis DRK1 (PbDRK1) expression during mycelium-yeast transition. It was observed that this gene is predominantly expressed in pathogenic yeast phase. In addition, we verified that when Dkr1 pharmacological inhibitor (iDrk1) was incubated with mycelium at 37°C, it alters the dimorphic switch. Hence, the purpose of this study was to investigate the role of PbDrk1 in cell wall modulation of P. brasiliensis. Previous data indicates a correlation between PbDrk1 and MAP kinase Hog1 over osmotic stress condition. In the present work it was observed decreased Hog1 phosphorylation levels after incubation with iDrk1 over osmotic stress but also related with cell wall integrity, confirming the participation of this HK in Hog1 signaling pathway. Additionally, we observed that PbDrk1 participates in fungal resistance to different cell wall disturbing agents, such as Congo Red, Calcofluor White and sodium chloride, by reducing yeasts viability after treatment with iDrk1. In order to verify the role of PbDRK1 in cell wall morphogenesis, we performed RTqPCR analysis. The results indicated that samples previously exposed to iDrk1 presented higher expression levels in several genes related to cell wall modulation. Among the genes analyzed, we highlighted FKS1, a β-glucan synthase which was 3,6-fold increase when compared to no treatment control. Confocal microscopy analysis and flow cytometry showed higher β-glucan exposure in cell surface of P. brasiliensis after 24 h incubation with iDrk1. Accordingly, through phagocytosis assay, it was observed a significant higher phagocytic index in yeasts treated with iDrk1 than control group, evidencing the role of PbDrk1 in cell wall modulation, which becomes a relevant target to be investigated. In parallel, the immune response profile was also assayed, with increased levels of pro-inflammatory cytokines. It is important to highlight that iDrk1 concentration used on this study did not reduce yeast viability. Finally, our data strongly suggests that PbDrk1 modulates cell wall components expression,among which we can point out b-glucan. The comprehension of this signaling pathway may be of great value to identify targets to antifungal molecular activity, since HK are not present in mammals.