Trichostatin A induces a unique set of microRNAs including miR-129-5p that blocks cyclin-dependent kinase 6 expression and proliferation in H9c2 cardiac myocytes

The role of miR-129-5p in regulating γ-globin expression and erythropoiesis in β-thalassemia

The regulation of γ-globin expression is crucial due to its beneficial effects on diseases like β-thalassemia and sickle cell disease. B-cell lymphoma/leukemia 11A (BCL11A) is a significant suppressor of γ-globin, and microRNAs (miRNAs) targeting BCL11A have been shown to alleviate this suppression. In our previous high-throughput sequencing, we identified an 11.32-fold increase in miR-129-5p expression in β-thalassemia patients. However, the regulatory mechanisms of miR-129-5p in the context of erythroid differentiation remain to be elucidated. Our study aimed to elucidate the role of miR-129-5p in γ-globin regulation and erythropoiesis. We measured miR-129-5p levels in peripheral blood from β-thalassemia major and intermedia patients. Fluorescence in situ hybridization, dual-luciferase reporter assays, miRNA pull down assays and western blot analyses were conducted to examine the effects of miR-129-5p on γ-globin expression and BCL11A repression. Cell proliferation, apoptosis, and erythroid differentiation were assessed using cell counting kit-8, Wright-Giemsa, and benzidine staining, and flow cytometry assays. The expression levels of miR-129-5p were significantly elevated in β-thalassemia patients and positively correlated with γ-globin synthesis while negatively correlating with liver damage. miR-129- 5p enhanced γ-globin gene expression in K562 and HUDEP-2 cells by effectively repressing BCL11A. Overexpression of miR-129-5p inhibited cell proliferation, induced cell cycle arrest at the G1/G0 phase, promoted apoptosis and stimulated erythroid differentiation and maturation. Conversely, inhibition of miR-129-5p produced opposite cellular effects. miR-129-5p acts as a positive regulator of erythroid differentiation and γ-globin synthesis. It offers a promising miRNA target for activating the γ-globin gene and reducing ineffective erythropoiesis in β-thalassemia patients.

Epigenetic mechanisms differentially regulate blood pressure and renal dysfunction in male and female Npr1 haplotype mice

We determined the epigenetic mechanisms regulating mean arterial pressure (MAP) and renal dysfunction in guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) gene-targeted mice. The Npr1 (encoding NPRA) gene-targeted mice were treated with class 1 specific histone deacetylase inhibitor (HDACi) mocetinostat (MGCD) to determine the epigenetic changes in a sex-specific manner. Adult male and female Npr1 haplotype (1-copy; Npr1+/-), wild-type (2-copy; Npr1+/+), and gene-duplicated heterozygous (3-copy; Npr1++/+) mice were intraperitoneally injected with MGCD (2 mg/kg) for 14 days. BP, renal function, histopathology, and epigenetic changes were measured. One-copy male mice showed significantly increased MAP, renal dysfunction, and fibrosis than 2-copy and 3-copy mice. Furthermore, HDAC1/2, collagen1alpha-2 (Col1α-2), and alpha smooth muscle actin (α-SMA) were significantly increased in 1-copy mice compared with 2-copy controls. The expression of antifibrotic microRNA-133a was attenuated in 1-copy mice but to a greater extent in males than females. NF-κB was localized at significantly lower levels in cytoplasm than in the nucleus with stronger DNA binding activity in 1-copy mice. MGCD significantly lowered BP, improved creatinine clearance, and repaired renal histopathology. The inhibition of class I HDACs led to a sex-dependent distinctive stimulation of acetylated positive histone marks and inhibition of methylated repressive histone marks in Npr1 1-copy mice; however, it epigenetically lowered MAP, repaired renal fibrosis, and proteinuria and suppressed NF-kB differentially in males versus females. Our results suggest a role for epigenetic targets affecting hypertension and renal dysfunction in a sex-specific manner.

Endocardial HDAC3 is required for myocardial trabeculation

Failure of proper ventricular trabeculation is often associated with congenital heart disease. Support from endocardial cells, including the secretion of extracellular matrix and growth factors is critical for trabeculation. However, it is poorly understood how the secretion of extracellular matrix and growth factors is initiated and regulated by endocardial cells. We find that genetic knockout of histone deacetylase 3 in the endocardium in mice results in early embryo lethality and ventricular hypotrabeculation. Single cell RNA sequencing identifies significant downregulation of extracellular matrix components in histone deacetylase 3 knockout endocardial cells. Secretome from cultured histone deacetylase 3 knockout mouse cardiac endothelial cells lacks transforming growth factor ß3 and shows significantly reduced capacity in stimulating cultured cardiomyocyte proliferation, which is remarkably rescued by transforming growth factor ß3 supplementation. Mechanistically, we identify that histone deacetylase 3 knockout induces transforming growth factor ß3 expression through repressing microRNA-129-5p. Our findings provide insights into the pathogenesis of congenital heart disease and conceptual strategies to promote myocardial regeneration.

Endocardial HDAC3 is required for myocardial trabeculation

BACKGROUND

Trabeculation, a key process in early heart development, is the formation of myocardial trabecular meshwork. The failure of trabeculation often leads to embryonic lethality. Support from endocardial cells, including the secretion of extracellular matrix (ECM) and growth factors is critical for trabeculation; however, it is unknown how the secretion of ECM and growth factors is initiated and regulated by endocardial cells.

METHODS

Various cellular and mouse models in conjunction with biochemical and molecular tools were employed to study the role of histone deacetylase 3 (HDAC3) in the developing endocardium.

RESULTS

We found that genetic deletion of Hdac3 in endocardial cells in mice resulted in early embryo lethality presenting as a hypotrabeculation cardiac phenotype. Single cell RNA sequencing identified several ECM components including collagens that were significantly downregulated in Hdac3 knockout (KO) endocardial cells. When cultured with supernatant from Hdac3 KO mouse cardiac endothelial cells (MCECs), wild-type mouse embryonic cardiomyocytes showed decreased proliferation, suggesting that growth signaling from Hdac3 KO MCECs is disrupted. Subsequent transcriptomic analysis revealed that transforming growth factor β3 (TGFβ3) was significantly downregulated in Hdac3 KO MCECs and Hdac3 cardiac endothelial KO hearts. Mechanistically, we identified that microRNA (miR)-129-5p was significantly upregulated in Hdac3 KO MCECs and Hdac3 cardiac endothelial KO hearts. Overexpression of miR-129-5p repressed Tgfβ3 expression in wild-type MCECs, whereas knockdown of miR-129-5p restored Tgfβ3 expression in Hdac3 KO MCECs.

CONCLUSION

Our findings reveal a critical signaling pathway in which endocardial HDAC3 promotes trabecular myocardium growth by stimulating TGFβ signaling through repressing miR-129-5p, providing novel insights into the etiology of congenital heart disease and conceptual strategies to promote myocardial regeneration.

LncRNA ROR modulates myocardial ischemia-reperfusion injury mediated by the miR-185-5p/CDK6 axis

LncRNAs and miRNAs are correlated with the pathogenesis of myocardial ischemia-reperfusion injury (MIRI). Whether lncRNA ROR or miR-185-5p plays a crucial role in MIRI is still unclear. In in-vitro, human cardiac myocytes (HCMs) were treated with hypoxia/reoxygenation (H/R). Wistar rats were used to set up an in-vitro I/R model by means of recanalization after ligation. Evaluation of the myocardial injury marker lactate dehydrogenase (LDH) in HCMs cells was performed. The expression of miR-185-5p and ROR, IL-1β, and IL-18 were detected by qRT-PCR. ELISA was also performed to evaluate the secretion of IL-1β and IL-18. Western blotting was carried out to determine CDK6, NLRP3, GSDMD-N, ASC, and cleaved-caspase1 protein expression. The relationship between miR-185-5p and CDK6 or ROR was confirmed by a dual-luciferase reporter assay. Our findings revealed that H/R treated HCMs showed a significantly decreased miR-185-5p expression and increased expression of CDK6 and ROR. ROR knockdown reduced H/R induced pyroptosis and inflammation, while knockdown of miR-185-5p accelerated the effect. Furthermore, miR-185-5p was negatively regulated and absorbed by ROR in HCMs. Overexpression of miR-185-5p reversed the H/R-induced cell pyroptosis and upregulation of LDH, IL-1β, and IL-18. In HCMs, miR-185-5p was also negatively regulated and related to CDK6 expression. Moreover, overexpression of CDK6 significantly inhibited the effects of miR-185-5p mimics on the inflammatory response and pyroptosis of HCMs. Knockdown of ROR alleviated H/R-induced myocardial injury by elevating miR-185-5p and inhibiting CDK6 expression. Taken together, our results show that the ROR/miR-185-5p/CDK6 axis modulates cell pyroptosis induced by H/R and the inflammatory response of HCMs.

Epigenetics and microRNAs in cardiovascular diseases

Cardiovascular diseases are among the leading causes of mortality worldwide. Besides environmental and genetic changes, these disorders can be influenced by processes which do not affect DNA sequence yet still play an important role in gene expression and which can be inherited. These so-called 'epigenetic' changes include DNA methylation, histone modifications, and ATP-dependent chromatin remodeling enzymes, which influence chromatin remodeling and gene expression. Next to these, microRNAs are non-coding RNA molecules that silence genes post-transcriptionally. Both epigenetic factors and microRNAs are known to influence cardiac development and homeostasis, in an individual fashion but also in a complex regulatory network. In this review, we will discuss how epigenetic factors and microRNAs interact with each other and how together they can influence cardiovascular diseases.

Promoting role of circ-Jarid2/miR-129-5p/Celf1 axis in cardiac hypertrophy

Cardiac hypertrophy is imposed much pressure on heart and threatening our live. Previous study suggested that dysregulation of Celf1 is largely connecting to neonatal cardiac dysfunction. Hence, we aimed to explore the precise function and probable regulatory mechanism upstream of Celf1in cardiac hypertrophy. Here, Ang-II treatment was implemented to stimulate hypertrophic phenotypes inH9C2 and MCM cells. Immunofluorescence assay was conducted to measure the surface area of cardiomyocytes. And qRT-PCR assay was conducted to investigate gene expression. Moreover, western blot assay was conducted to probe the protein levels. Results uncovered that Celf1 expression was increased dependent on elevated Ang-II concentration, and that inhibited Celf1 could relieve the Ang-II-caused cardiac hypertrophy. Significantly, Celf1was found to be targeted by miR-129-5p but then released via the sponging role of circ-Jarid2. Furthermore, circ-Jarid2 was found to promote cardiac hypertrophy, whereas miR-129-5p played suppressing parts in hypertrophic cardiomyocytes. Moreover, we verified circ-Jarid2 contributed to cardiac hypertrophy via miR-129-5p/Celf1 axis both in vitro and in vivo. In conclusion, circ-Jarid2/miR-129-5p/Celf1 axis aggravates cardiac hypertrophy, which provides new ideas for developing treatment strategies for patients with cardiac hypertrophy.

MicroRNA-129-5p suppresses proliferation, migration and invasion of retinoblastoma cells through PI3K/AKT signaling pathway by targeting PAX6

BACKGROUND

Retinoblastoma (RB) is the most common primary intraocular malignancy in children. Accumulating evidences have clarified that microRNAs (miRNAs) modulated signaling molecules by acting as oncogenes or tumor-suppressor genes in RB. Thus, in our study, we aimed to investigate the function of miR-129-5p in RB cells through PI3K/AKT signaling pathway by targeting PAX6. Two RB cell lines, Y79 and WERI-Rb-1, were selected in our study, followed by transfection of miR-129-5p inhibitor or si-PAX6 to explore the regulatory role of miR-129-5p in RB cell proliferation, invasion and migration.

MATERIAL AND METHODS

Dual-luciferase assay was used for the detection of targeting relationship between miR-129-5p and PAX6. Besides, western blot analysis was applied to detect expression of cell cycle-related factors (CDK2 and Cyclin E) and PI3K/AKT signaling pathway-related factors (p-AKT and AKT). Nude mice tumorigenesis experiment was used to evaluate the effect of miR-129a-5p on RB growth in vivo.

RESULTS

miR-129-5p was down-regulated in RB cell lines. miR-129-5p directly targeted the 3'-untranslated region of PAX6. Artificial down-regulation of miR-129-5p promoted cell proliferation, migration and invasion in RB cell lines Y79 and WERI-Rb-1, and promoted RB growth in vivo via PI3K/AKT signaling pathway, which could be reversed by transfection with silencing PAX6.

CONCLUSION

This study provides evidences that RB progression was suppressed by overexpressed miR-129-5p via direct targeting of PAX6 through PI3K/AKT signaling pathway, which may provide a molecular basis for better treatment for RB.

Deduction of novel genes potentially involved in hypoxic AC16 human cardiomyocytes using next-generation sequencing and bioinformatics approaches

Atherosclerotic cardiovascular disease and acute myocardial infarction are the leading causes of mortality worldwide, and apoptosis is the major pathway of cardiomyocyte death under hypoxic conditions. Although studies have reported changes in the expression of certain pro‑apoptotic and anti‑apoptotic genes in hypoxic cardiomyocytes, genetic regulations are complex in human cardiomyocytes and there is much that remains to be fully elucidated. The present study aimed to identify differentially expressed genes in hypoxic human AC16 cardiomyocytes using next‑generation sequencing and bioinformatics. A total of 24 genes (15 upregulated and 9 downregulated) with potential micro (mi)RNA‑mRNA interactions were identified in the miRmap database. Utilising the Gene Expression Omnibus database of cardiac microvascular endothelial cells, tensin 1, B‑cell lymphoma 2‑interacting protein 3 like, and stanniocalcin 1 were found to be upregulated, and transferrin receptor and methyltransferase like 7A were found to be downregulated in response to hypoxia. Considering the results from miRmap, TargetScan and miRDB together, two potential miRNA‑mRNA interactions were identified: hsa‑miRNA (miR)‑129‑5p/CDC42EP3 and hsa‑miR‑330‑3p/HELZ. These findings contribute important insights into possible novel diagnostic or therapeutic strategies for targeting cardiomyocytes under acute hypoxic stress in conditions, including acute myocardial infarction. The results of the present study also introduce an important novel approach in investigating acute hypoxic pathophysiology.