High Glucose–Induced Dysfunction of Endothelial Cells can be Restored by HoxA9EC

Comprehensive analysis of the m6A demethylase FTO in endothelial dysfunction by MeRIP sequencing

N6-methyladenosine (m6A) is the most general post-transcriptional modification of eukaryotic mRNAs and long-stranded non-coding RNAs. In this process, It has been shown that FTO associates with the m6A mRNA demethylase and plays a role in diabetic vascular endothelial dysfunction. In the present study, we detected FTO protein expression in HUVECs by Western blot and found that FTO was highly expressed in all disease groups relative to the control group. To explore the mechanism of FTO in T2DM vasculopathy, we performed an analysis by methylated RNA immunoprecipitation sequencing (MeRIP-seq) to elucidate the role of aberrant m6A modification and mRNA expression in endothelial dysfunction. The results showed 202 overlapping genes with varying m6A modifications and varied mRNA expression, and GO and KEGG enrichment analysis revealed that these genes were predominantly enriched in pathways associated with T2DM complications and endothelial dysfunction. By an integrated analysis of MeRIP-seq and RNA-seq results, the IGV plots showed elevated kurtosis of downstream candidate gene modifications, which may be downstream targets for FTO to exercise biological functions. HOXA9 and PLAU mRNA expression levels were significantly down after FTO inhibition. In the current work, we set up a typological profile of the m6A genes among HUVECs as well as uncovered a hidden relationship between RNA methylation modifications for T2DM vasculopathy-associated genes. Taken together, this study indicates that endothelial functional impairment is present in T2DM patients and may be related to aberrant expression of FTO.

HOXA9 transcription factor is a double-edged sword: from development to cancer progression

The HOXA9 transcription factor serves as a molecular orchestrator in cancer stemness, epithelial-mesenchymal transition (EMT), metastasis, and generation of the tumor microenvironment in hematological and solid malignancies. However, the multiple modes of regulation, multifaceted functions, and context-dependent interactions responsible for the dual role of HOXA9 as an oncogene or tumor suppressor in cancer remain obscure. Hence, unravelling its molecular complexities, binding partners, and interacting signaling molecules enables us to comprehend HOXA9-mediated transcriptional programs and molecular crosstalk. However, it is imperative to understand its central role in fundamental biological processes such as embryogenesis, foetus implantation, hematopoiesis, endothelial cell proliferation, and tissue homeostasis before designing targeted therapies. Indeed, it presents an enormous challenge for clinicians to selectively target its oncogenic functions or restore tumor-suppressive role without altering normal cellular functions. In addition to its implications in cancer, the present review also focuses on the clinical applications of HOXA9 in recurrence and drug resistance, which may provide a broader understanding beyond oncology, open new avenues for clinicians for accurate diagnoses, and develop personalized treatment strategies. Furthermore, we have also discussed the existing therapeutic options and accompanying challenges in HOXA9-targeted therapies in different cancer types.

MicroRNA-139-5p mediates BMSCs impairment in diabetes by targeting HOXA9/c-Fos

The properties and functions of BMSCs were altered by the diabetic microenvironment, and its mechanism was not very clear. In recent years, the regulation of the function of BMSCs by microRNA has become a research hotspot, meanwhile, HOX genes also have been focused on and involved in multiple functions of stem cells. In this study, we investigated the role of miR-139-5p in diabetes-induced BMSC impairment. Since HOXA9 may be a target gene of miR-139-5p, we speculated that miR-139-5p/HOXA9 might be involved in regulating the biological characteristics and the function of BMSCs in diabetes. We demonstrated that the miR-139-5p expression was increased in BMSCs derived from STZ-induced diabetic rats. MiR-139-5p mimics were able to inhibit cell proliferation, and migration and promoted senescence and apoptosis in vitro. MiR-139-5p induced the down-regulated expression of HOXA9 and c-Fos in BMSCs derived from normal rats. Moreover, miR-139-5p inhibitors reversed the tendency in diabetic-derived BMSCs. Further, gain-and-loss function experiments indicated that miR-139-5p regulated the functions of BMSCs by targeting HOXA9 and c-Fos. In vivo wound model experiments showed that the downregulation of miR-139-5p further promoted the epithelialization and angiogenesis of diabetic BMSC-mediated skin. In conclusion, induction of miR-139-5p upregulation mediated the impairment of BMSCs through the HOXA9/c-Fos pathway in diabetic rats. Therefore, miR-139-5p/HOXA9 might be an important therapeutic target in treating diabetic BMSCs and diabetic complications in the future.

Nuclear Factor Kappa-B/Homeobox A9-Mediated Modulation of Leucine-Rich Repeat Flightless-Interacting Protein 1 Is Involved in Advanced Glycation End Product-Induced Endothelial Dysfunction

BACKGROUND

Pathogenesis of cardiovascular diseases begins with endothelial dysfunction. Our previous study has shown that advanced glycation end products (AGE) could inhibit the expression of homeobox A9 (Hoxa9), thereby inducing endothelial dysfunction. Leucine-rich repeat flightless-interacting protein 1 (LRRFIP1) has been found to participate in a variety of pathological processes, but reports of its role in endothelial dysfunction are rare.

OBJECTIVES

This study aims to investigate whether LRRFIP1 is involved in AGE-induced endothelial dysfunction through Hoxa9-mediated transcriptional activation.

METHODS

Chromatin immunoprecipitation was used to detect the transcriptional regulation of Hoxa9 on LRRFIP1 promoters. Human umbilical vein endothelial cells were treated with AGE or pyrrolidinedithiocarbamate (nuclear factor kappa-B [NF-κB] inhibitor). Moreover, changes in apoptosis, proliferation, migration, release of nitric oxide, and angiogenesis were detected.

RESULTS

Hoxa9 promotes LRRFIP1 expression by binding to the -LRRFIP1 promoter. Meanwhile, overexpression of LRRFIP1 inhibited phosphorylation of P65 and elevated expression of Hoxa9. Overexpression of LRRFIP1 or/and Hoxa9 reversed the effects of AGE on HUVEC. AGE-induced inhibition on the expression of LRRFIP1 and Hoxa9 could be reversed by the NF-κB inhibitor.

CONCLUSION

LRRFIP1 is involved in AGE-induced endothelial dysfunction via being regulated by the NF-κB/Hoxa9 axis.