Previous research has demonstrated a significant relationship between ferroptosis and various forms of cardiomyopathy[6, 7]. Hypertrophic cardiomyopathy, which is a prevalent form of cardiomyopathy, is more closely linked to genetic factors in its pathogenesis. It is possible that the pathophysiology of hypertrophic cardiomyopathy involves ferroptosis. In this study, bioinformatics analysis, GEO database and FerrDB V2 were used to investigate the correlation between ferroptosis and hypertrophic cardiomyopathy, as well as the lncRNA-associated competing endogenous RNA (ceRNA) network of ferroptosis-related genes.
We initially screened 64 ferroptosis-related genes associated with HCM by WGCNA and FerrDB V2. Out of these, 32 were classified as driver genes and 30 as suppressor genes, with the remaining 2 classified as marker genes. The majority of ferroptosis-related genes in HCM belonging to the categories of driver and suppressor genes. Enrichment analysis of these genes indicated that they were mainly enriched in pathways concerning iron ion homeostasis and lipid metabolism. This implies that ferroptosis may have a regulatory role in HCM[14]. Following subsequent screening by the PPI network, seven hub genes were identified: PPARG, CD44, ACO1, SIRT1, CDKN2A, ADIPOQ, and TFRC. After validating in other gene expression datasets, we obtained five hub-genes, which were further screened by constructing a ceRNA network to acquire two key regulatory lncRNAs, namely NUTM2B-AS1 and XIST, and two hub-genes, PPARG and CD44.
Peroxisome proliferator-activated receptor gamma (PPARG) is a ligand-activated transcription factor of the nuclear hormone receptor superfamily that is abundant in adipose tissue [15]. Previous research has indicated that the activation of PPARG plays a crucial role in regulating several pathophysiological functions in the cardiovascular system[16, 17]. PPARγ activation has been demonstrated to impact mitochondrial function, leading to the activation of cardiac hypertrophy[18]. The present study's findings were consistent with the notion that PPARG may have a role in HCM's pathophysiology. Moreover, the enrichment analysis suggests the PPAR signalling pathway's significant contribution to HCM. CD44, a multifunctional transmembrane glycoprotein, is broadly expressed throughout the body. HA serves as the principal ligand for CD44. The interactions between CD44, HA, and their contribution to myocardial fibrosis and cardiac remodelling are critical pathophysiological mechanisms in the development of HCM[19, 20]. The aforementioned outcomes additionally corroborate the conclusions of this research, showing a significant association between HCM and CD44.
The two hub genes mentioned above were both related to ferroptosis and the results suggest that they influenced HCM pathogenesis, a conclusion supported by previous studies. Therefore, these two hub genes were potentially crucial in regulating the ferroptosis process and their involvement may be significant in the development of HCM. To investigate the specific regulatory mechanisms, further experimental studies are required.
Long non-coding RNAs (lncRNAs) are described as untranslated transcripts with more than 200 nucleotides. Although cannot translated into proteins, lncRNAs play an important role in controlling gene expression. The competitive endogenous RNA (ceRNA) theory depicts that lncRNAs can act as miRNA “sponges”, and kept miRNAs away from their target mRNAs, consequently constituting a regulatory network[21]. The regulatory function of lncRNA-associated ceRNA networks was explored by comparing the predicted data from bioinformatics analysis with differentially expand miRNAs obtained from GEO data. Constructing ceRNA networks was done according to ceRNA theory, allowing for reliable and possible ceRNA regulatory mechanisms. The result showed that the lncRNA-associated ceRNA network consisted of 39 lncRNA nodes, 5 miRNA nodes, and 2 mRNAs nodes. LncRNA NUTM2B-AS1 and lncRNA XIST were the two key lncRNA nodes of the ceRNA network for sponging four miRNA nodes simultaneously.
The impact of lncRNA XIST on cardiomyocytes has been well investigated. lncRNA XIST manages myocardial cell injury by its miRNAs sponging, including miR-130-3p[22], miR-449[23], miR-150-5p[24], miR-191-5p[25], etc. In the case of cardiac hypertrophy, lncRNA XIST regulates cardiomyocyte hypertrophy by targeting miR-330-3p[26] and miR-101[27]. The function of lncRNA XIST in ferroptosis has yet to be reported. Our research presents an alternative mechanism for how lncRNA XIST regulated cardiomyocyte hypertrophy and requires further experimental investigation. Research on the lncRNA NUTM2B-AS1 is scarce, and its involvement in HCM and ferroptosis has not been documented previously. The current study reveals the potential of its regulatory function in HCM, but additional experimental confirmation is required.
There were a number of limitations to this study. Firstly, the availability of datasets was limited. The number of differentially expressed miRNAs and lncRNAs obtained was also restricted, and the constructed ceRNA network was imperfect. Secondly, FerrDb v2 was used to derive the ferroptosis-related genes, which is continuously updated and may require discovering more genes in the future. Thirdly, the potential HCM ferroptosis-associated genes and their ceRNA regulatory network identified in this study still need further support in the literature and validation by laboratory evidence.