Down-regulation of histone deacetylase 7 reduces biological activities of retinal microvascular endothelial cells under high glucose condition and related mechanism

AIM

To investigate the expression and effect of histone deacetylase 7 (HDAC7) in human retinal microvascular endothelial cells (HRMECs) under high glucose condition and related mechanism, and the expression of HDAC7 in the retinal tissue in diabetic rats.

METHODS

The expression of HDAC7 in HRMECs under high glucose and the retinal tissue from normal or diabetic rats were detected with immunohistochemistry and Western blot. LV-shHDAC7 HRMECs were used to study the effect of HDAC7 on cell activities. Cell count kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, scratch test, Transwell test and tube formation assay were used to examine the ability of cell proliferation, migration, and angiogenesis. Finally, a preliminary exploration of its mechanism was performed by Western blot.

RESULTS

The expression of HDAC7 was both up-regulated in retinal tissues of diabetic rats and high glucose-treated HRMECs. Down-regulation of HDAC7 expression significantly reduced the ability of proliferation, migration, and tube formation, and reversed the high glucose-induced high expression of CDK1/Cyclin B1 and vascular endothelial growth factor in high glucose-treated HRMECs.

CONCLUSION

High glucose can up-regulate the expression of HDAC7 in HRMECs. Down-regulation of HDAC7 can inhibit HRMECs activities. HDAC7 is proposed to be involved in pathogenesis of diabetic retinopathy and a therapeutic target.

HDAC7 inhibits cell proliferation via NudCD1/GGH axis in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. In the absence of effective molecular markers for TNBC, there is an urgent clinical need for promising therapeutic target for TNBC. Histone deacetylases (HDACs), key regulators for chromatin remodeling and gene expression, have been suggested to play critical roles in cancer development. However, little is known ~the functions and implications of HDACs in TNBC treatment in the future. By analyzing the expression and prognostic significance of HDAC family members in TNBC through TCGA and METABRIC databases, HDAC7 was found to be downregulated in TNBC samples and the survival of patients with lower expression of HDAC7 was shorter. Furthermore, HDAC7 was negatively associated with NudC domain containing 1 (NudCD1) and γ-glutamyl hydrolase (GGH). Loss of NudCD1 or GGH predicted improved overall survival time (OS) of patients with TNBC. In vitro experiments showed that silencing of HDAC7 enhanced TNBC cell proliferation, while overexpression HDAC7 inhibited TNBC cell proliferation. The results of functional experiments confirmed that HDAC7 negatively modulated GGH and NudCD1 expression. Furthermore, decrease of NudCD1 or GGH inhibited cell proliferation. Notably, the HDAC7-NudCD1/GGH axis was found to be associated with NK cell infiltration. Overall, the present study revealed a novel role of HDAC7-NudCD1/GGH axis in TNBC, which might provide a promising treatment strategy for patients with TNBC.

OIP5-AS1 modulates epigenetic regulator HDAC7 to enhance non-small cell lung cancer metastasis via miR-140-5p

Long non-coding RNAs have been reported to be involved in non-small cell lung cancer (NSCLC) progression. However, whether Opa-interacting protein 5 antisense RNA 1 (OIP5-AS1) serves a role in NSCLC remains unclear. Bioinformatics analysis of The Cancer Genome Atlas datasets showed clinical significance and relevance of OIP5-AS1 in NSCLC. Western blotting and reverse transcription-quantitative PCR revealed protein and RNA expression levels of the genes [including OIP5-AS1, microRNA (miR)-140-5p, histone deacetylase 7 (HDAC7) and vascular endothelial growth factor A (VEGFA)]. Direct associations between the genes (miR-140-5p and OIP5-AS1, or miR-140-5p and HDAC7) were confirmed using a dual-luciferase reporter assay. Lymphatic vessel formation and invasion ability were detected using a lymphatic vessel formation assay and Transwell invasion assay. OIP5-AS1 knockdown attenuated lymphatic vessel length and invasion. The role of OIP5-AS1 was reverted by miR-140-5p. HDAC7 and VEGFA are downstream effectors of miR-140-5p-mediated NSCLC metastasis. OIP5-AS1, miR-140-5p, HDAC7 and VEGFA were all dysregulated in human clinical NSCLC tumor tissues. In conclusion, the present results demonstrated a novel mechanism for OIP5-AS1-induced metastatic phenotypes of NSCLC via the miR-140-5p/HDAC7/VEGFA axis.

A histone deacetylase 7-derived peptide promotes vascular regeneration via facilitating 14-3-3γ phosphorylation

Histone deacetylase 7 (HDAC7) plays a pivotal role in the maintenance of the endothelium integrity. In this study, we demonstrated that the intron-containing Hdac7 mRNA existed in the cytosol and that ribosomes bound to a short open reading frame (sORF) within the 5'-terminal noncoding area of this Hdac7 mRNA in response to vascular endothelial growth factor (VEGF) stimulation in the isolated stem cell antigen-1 positive (Sca1⁺ ) vascular progenitor cells (VPCs). A 7-amino acid (7A) peptide has been demonstrated to be translated from the sORF in Sca1⁺ -VPCs in vitro and in vivo. The 7A peptide was shown to receive phosphate group from the activated mitogen-activated protein kinase MEKK1 and transfer it to 14-3-3 gamma protein, forming an MEKK1-7A-14-3-3γ signal pathway downstream VEGF. The exogenous synthetic 7A peptide could increase Sca1⁺ -VPCs cell migration, re-endothelialization in the femoral artery injury, and angiogenesis in hind limb ischemia. A Hd7-7sFLAG transgenic mice line was generated as the loss-of-function model, in which the 7A peptide was replaced by a FLAG-tagged scrabbled peptide. Loss of the endogenous 7A impaired Sca1⁺ -VPCs cell migration, re-endothelialization of the injured femoral artery, and angiogenesis in ischemic tissues, which could be partially rescued by the addition of the exogenous 7A/7Ap peptide. This study provides evidence that sORFs can be alternatively translated and the derived peptides may play an important role in physiological processes including vascular remodeling.

miR-193b-5p regulates chondrocytes metabolism by directly targeting histone deacetylase 7 in interleukin-1β-induced osteoarthritis

There is increasing evidence regarding the pivotal roles of microRNAs (miRNAs) and histone deacetylases (HDACs) in the development of osteoarthritis (OA). This study aimed to determine whether miR-193b-5p regulates HDAC7 expression directly to affect cartilage degeneration. Expression levels of miR-193b-5p, HDAC7, matrix metalloproteinase 3 (MMP3), and MMP13 were determined in normal and OA cartilage and primary human chondrocytes (PHCs) stimulated with interleukin-1β (IL-1β). PHCs were transfected with a miR-193b-5p mimic or inhibitor to verify whether miR-193b-5p influences the expression of HDAC7 and MMPs. A luciferase reporter assay was performed to demonstrate the binding between miR-193b-5p and the 3'-untranslated region (UTR) of HDAC7. Expression of miR-193b-5p was reduced in IL-1β-stimulated PHCs and in OA cartilage compared to that in normal cartilage. Luciferase reporter assay exhibited the repressed activity of the reporter construct containing the 3'UTR of HDAC7. Both miR-193b-5p overexpression and HDAC7 inhibition decreased the expression of MMP3 and MMP13, whereas the inhibition of miR-193b-5p enhanced HDAC7, MMP3, and MMP13 expression. miR-193b-5p downregulates HDAC7 directly and, as a result, inhibits MMP3 and MMP13 expression, which suggests that miR-193b-5p has a protective role in OA.

Endothelial progenitor cells contribute to neovascularization of non-small cell lung cancer via histone deacetylase 7-mediated cytoskeleton regulation and angiogenic genes transcription

To supply tumor tissues with nutrients and oxygen, endothelial progenitor cells (EPCs) home to tumor sites and contribute to neovascularization. Although the precise mechanism of EPCs-induced neovascularization remains poorly understood in non-small cell lung cancer (NSCLC), histone deacetylase 7 (HDAC7) is considered as a critical regulator. To explore the function of HDAC7 in neovascularization induced by EPCs, tube formation assay, immunofluorescence, microarray, Western blot analysis and animal models were performed. In vitro, HDAC7 abrogation led to the activation of Rho-associated coiled-coil containing protein kinase/myosin light chain 2 pathway concomitant with ERK dephosphorylation, causing the instability of cytoskeleton and collapse of tube formation. In vivo, absence of HDAC7 impaired the vascular lumen integrity and decreased the functional blood perfusion, inhibiting the growth of tumor. At the level of transcription, HDAC7 silencing upregulated antiangiogenic genes and suppressed proangiogenic genes collectively, turning off the angiogenic switch during vessel formation. Taken together, HDAC7 plays a dual role in maintaining the structural and nonstructural functions of EPCs. Our work demonstrates the molecular mechanism by which HDAC7 contributes to the angiogenic property of EPCs and provides a rational basis for specific targeting of antiangiogenic strategies in lung cancer.