Establishment of Ferroptosis-Associated Molecular Subtypes and Hub Genes Related to the Immune Microenvironment of Heart Failure

Background: Ferroptosis is a form of iron-dependent regulated cell death, and prior work has highlighted the potential utility of ferroptosis-inducing agents as tools to treat heart failure (HF). To date, however, no detailed examinations of the prognostic utility of ferroptosis-related genes (FRGs) in HF have been conducted. Methods: We used established genomic identification of FRGs for total samples in the gene expression omnibus (GEO) database, screened for differentially expressed FRGs, performed protein-protein interaction analysis and functional analysis of HF immune microenvironment subtypes. Subsequently, we applied tools to calculate immune cell infiltration, compare immune cell, immune response genomic and HLA gene differences between subtypes, and perform candidate drug identification. Finally, preliminary in vivo validation of the screened central genes was performed in animal models. Results: FRGs were compared between samples from HF and healthy control donors, revealing 62 of these genes to be differentially expressed as a function of HF status. HF patient-derived tissues exhibited significant changes in the expression of HLA genes, increase immune cell infiltration, and higher levels of other immune-related genes within the associated immune microenvironment. These FRGs were then leveraged to establish two different immune-related subtypes of HF based on clustering analysis results, after which these subtypes were characterized in further detail. Functional enrichment analyses revealed the identified differentially expressed genes to be enriched in key immune-related pathways including the primary immunodeficiency, natural killer cell-mediated cytotoxicity, FcϵRI signaling, and antigen processing and presentation pathways. The impact of the immune microenvironment was also explored through functional analyses, core gene analyses, and efforts to identify potential drug candidates for HF patients. Moreover, four key hub genes were identified as promising targets for therapeutic intervention in HF, including HDAC1, LNPEP, PSMA1, and PSMA6. Subsequent preclinical work in a mouse model system supported a potential role for HDAC1 as an important biomarker associated with the incidence of HF. Conclusions: To sum up, these results emphasize the importance of ferroptosis as a regulator of the HF-related immune microenvironment, highlighting viable avenues for the further study of molecular targets amenable to pharmacological intervention with the aim of treating this debilitating disease.