Proteínas antioxidantes sintetizadas por Ganoderma spp.: Produção em Fermentação Submersa e Potencial Terapêutico Frente ao HTLV

Abstract

The genus Ganoderma comprises medicinal mushroom species with considerable potential for the discovery of low-toxicity bioactive molecules. Although still poorly explored, their proteins have demonstrated remarkable potential as immunomodulatory, anticancer, antiviral, and antioxidant agents. These properties make them promising candidates for the development of therapies against Human T-cell Lymphotropic Virus Type 1 (HTLV-1), the etiological agent of Adult T-cell Leukemia/Lymphoma (ATL) and HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), diseases that severely compromise the quality of life and life expectancy of people living with HTLV-1 and for which no targeted therapies are currently available. In this context, the present study aimed to produce and characterize protein extracts from Ganoderma spp. cultivated under different submerged fermentation conditions and to investigate their selective cytotoxic potential against an HTLV-1-infected cell line. Two Ganoderma strains were evaluated: the reference medicinal species Ganoderma sichuanense (CC22) and an Amazonian isolate molecularly identified as Ganoderma multiplicatum (1962). The evaluation of cultivation conditions showed that static cultivation resulted in higher protein yields, particularly for G. sichuanense. Despite species-specific differences associated with fungal metabolism, all protein extracts exhibited antioxidant activity. The protein extract with the highest antioxidant activity from each strain was selected for subsequent cell-based assays. Protein extracts from both species showed no cytotoxicity toward healthy peripheral blood mononuclear cells (PBMCs). However, against the HTLV-1-infected MT-2 cell line, G. sichuanense exhibited a more pronounced selective cytotoxic effect. The immunomodulatory activity also differed between species, with G. multiplicatum displaying a predominantly pro-inflammatory profile, whereas G. sichuanense promoted a more immunoregulatory response. Based on these findings, G. sichuanense was selected for cultivation under different stress conditions as a strategy to redirect fungal metabolism toward the synthesis of proteins with enhanced biological activity. Thermal stress proved promising for this purpose, resulting in an approximately fourfold increase in cytotoxicity against the HTLV-1-infected MT-2 cell line, while also enhancing antioxidant activity and the immunomodulatory response. These findings provide a foundation for future studies aimed at elucidating the underlying mechanisms of action and identifying the proteins responsible for the observed biological activities. To the best of our knowledge, this is the first report describing proteins obtained from Ganoderma mushrooms with selective cytotoxic activity against an HTLV-1-infected cell line.