Work

Transcriptomic analysis reveals the molecular mechanisms of methylene blue-mediated photodynamic therapy against Microsporum canis

Year: 2026

Type: article

Abstract: BackgroundMicrosporum canis, a primary cause of dermatophytosis, presents a growing therapeutic challenge due to the limitations and emerging resistance associated with conventional antifungals. Methylene Blue-mediated Photodynamic Therapy (MB-PDT) is a promising alternative, but its molecular mechanisms against this pathogen are poorly understood.MethodsThis study employed RNA-sequencing (RNA-Seq) to investigate the global transcriptomic response of M. canis to a sub-inhibitory concentration of MB-PDT. Differentially expressed genes (DEGs) were identified, and their biological functions were explored through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Key gene expression changes were validated using qRT-PCR.ResultsA total of 619 DEGs (341 upregulated, 278 downregulated) were identified. Enrichment analysis revealed that MB-PDT significantly disrupts fundamental cellular processes, with the "ribosome" and "steroid biosynthesis" pathways being the most affected. The transcriptomic profile indicated that MB-PDT induces widespread oxidative damage to the cell membrane, mitochondria, and ribosomes, while also causing genotoxicity. In response, M. canis activated pathways related to membrane repair, stress response, and ribosome biogenesis. Crucially, the upregulation of genes associated with programmed cell death (PCD), such as Vegetative incompatibility protein HET-E-1 and Acid ceramidase, suggests that overwhelming cellular damage triggers an intrinsic suicide pathway.ConclusionMB-PDT appears to exert its potent antifungal effect against M. canis through a multi-targeted mechanism that may overwhelm cellular repair systems, leading to the induction of PCD. This non-specific mode of action is thought to minimize the risk of resistance, highlighting MB-PDT as a promising therapeutic alternative for dermatophytosis.

Source: Photodiagnosis and Photodynamic Therapy

DOI: 10.1016/j.pdpdt.2026.105364