Altered phagocytosis and morphogenesis of phenotypic switching-derived strains of the pathogenic Candida tropicalis co-cultured with phagocytic cells

• Published in: Microbial pathogenesis 2023-08, Vol.181, p.106186-106186, Article 106186
• Main Authors: Paulo, Eloiza A., de Souza, Cassia M., Perini, Hugo F., de Almeida, Ricardo S.Couto, Costa, Ivete C., Pavanelli, Wander R., Furlaneto-Maia, Luciana, Furlaneto, Marcia C.
• Format: Article
• Language: English
• Subjects: Candida albicans; Candida tropicalis; Coculture Techniques; Humans; Hyphal growth; Macrophages, Peritoneal; Morphogenesis; Phagocytosis; Phenotypic switching; WOR1 transcription factor
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1016/j.micpath.2023.106186

Candida tropicalis is among the most prevalent human pathogenic yeast species. Switch states of C. tropicalis differ in virulence traits. Here, we evaluate the effect of phenotypic switching on phagocytosis and yeast-hyphae transition in C. tropicalis. C. tropicalis morphotypes included a clinical strain and two switch strains (rough variant and rough revertant). In vitro, phagocytosis assay was performed using peritoneal macrophages and hemocytes. The proportion of hyphal cells was ascertained by scoring morphology using optical microscopy. Expression of the WOR1 (White-opaque regulator 1) and EFG1 (Enhanced filamentous growth protein 1) was determined by quantitative PCR. The rough variant was more resistant to in vitro phagocytosis by peritoneal macrophages than that observed for the clinical strain, while hemocytes phagocytosed clinical and rough variant to the same extent. The rough revertant was more phagocytosed than the clinical strain by both phagocytes. During co-incubation with phagocytic cells, the clinical strain of C. tropicalis exists mainly as blastoconidia. The co-culture of the rough variant with macrophages resulted in a higher percentage of hyphae than blastoconidia cells, while in co-culture with hemocytes, no differences were observed between the percentage of hyphae and blastoconidia. The expression levels of WOR1 in the rough variant co-cultured with phagocytes were significantly higher than they were in the clinical strain. Differences on phagocytosis and hyphal growth between switch states cells of C. tropicalis co-cultured with phagocytic cells were observed. The pronounced hyphal growth may affect the complex host-pathogen relationship and favor the pathogen to escape phagocytosis. The pleiotropic effects of phenotypic switching suggest that this event may contribute to the success of infection associated with C. tropicalis. •In vitro phagocytosis of switch states cells of C. tropicalis was determined.•The percentage of the cells that underwent hyphal morphogenesis was assessed.•Phenotypic switching had effect on phagocytosis and yeast-hyphae transition.•Exposure to Congo red affected hyphal morphogenesis and phagocytosis in switch strain.•Expression of WOR1 was upregulated in the most filamentous switch strain.