Análise transcriptômica parcial de himatanthus drasticus e avaliação de suas proteínas de látex: implicações para a viabilidade celular, imunomodulação e potencial terapêutico

Abstract

The latex of Himatanthus drasticus contains diverse bioactive compounds with therapeutic potential. However, research on its constituents, particularly the small protein fraction (HdLP) and its biological activities, remains limited. Additionally, no genomic or transcriptomic data for this plant are available in public databases. This study aims to bridge some of these gaps by partially characterizing the transcriptomic profile of leaves and bark and analyzing the composition and biological effects of latex proteins of H. drasticus. The protein fraction of H. drasticus latex was sub-fractionated using ion exchange chromatography (DEAE-Sepharose), analyzed via electrophoresis, and characterized through mass spectrometry. In vitro viability assays were conducted on RAW264.7, L929, and C2C12 cell lines to evaluate the cytotoxicity of HdLP and its sub-fractions. Additionally, in vivo experiments in Swiss mice were performed to assess the impact of HdLP on hyperglycemia, infection, and immunomodulation. Transcriptomic analysis identified differentially expressed transcripts between leaves and bark associated with metabolic regulation, defense responses, and synthesis of bioactive compounds, providing novel insights into the molecular landscape of this plant. Chromatographic analysis of HdLP showed the presence of two distinct sub-fractions, Hd-1 and Hd-2. Mass spectrometry (MS) analysis detected 27 proteins/peptides in subfraction Hd-1 and 26 in Hd-2. Cell viability assays demonstrated distinct concentration-dependent effects: HdLP reduced viability in RAW264.7 and L929 cells but increased it in C2C12 cells at the same concentration range (2-31.3 μg/mL). Hd-1 consistently promoted viability at almost all the tested concentrations (0.1-25 μg/mL), whereas Hd-2 displayed a biphasic response by increasing viability at lower concentrations (0.2-3.9 μg/mL) and reducing it at higher ones (62.5-125 μg/mL). In vivo studies indicated that HdLP had no significant impact on hyperglycemia or infection but exhibited immunomodulatory effects, including leukocyte depletion and increased platelet counts, along with mild hepatotoxicity. This study represents the first transcriptomic investigation of H. drasticus, provides a deeper understanding of HdLP composition, and lays the groundwork for future research into its mechanisms of action and potential applications in immunomodulation and regenerative medicine.