IL-6 regulates the bone metabolism and inflammatory microenvironment in aging mice by inhibiting Setd7

Aging, which has become a worldwide problem, leads to the degeneration of multiple organs and tissues. Two of the main changes in aging are dysregulation of the tissue microenvironment and abnormal functioning of specific stem cells. Bone marrow stem cells (BMSCs) in the aging microenvironment are not only effector cells but also immunomodulatory cells that change the microenvironment. IL-6 is a primary inflammatory response factor associated with bone diseases. In this study, we stimulated BMSCs with IL-6 to investigate a novel mechanism of age-related osteoporosis. IL-6 activated the TLR2, TLR4 and AKT pathway as well as inhibited the expression of β-catenin and Setd7. In addition, Setd7 expression in the bone tissues of aged mice was suppressed. Setd7 not only promoted BMSC osteogenic differentiation but also mediated proinflammatory gene expression in BMSCs under IL-6 stimulation. Due to its dual functions in BMSCs, Setd7 may be a novel molecular target for age-related osteoporosis prevention and treatment.

Transcriptomic Analysis of Histone Methyltransferase Setd7 Knockdown and Phenethyl Isothiocyanate in Human Prostate Cancer Cells

BACKGROUND/AIM

Transcriptomic analysis was performed to evaluate the differential gene expression profiles of Setd7 knockdown (KD) and the effects of phenethyl isothiocyanate (PEITC) in human prostate cancer (PCa) LNCaP cells.

MATERIALS AND METHODS

RNA isolated from wild-type and Setd7-KD LNCaP cells in the presence or absence of PEITC was subjected to microarray analysis followed by Ingenuity® Pathway Analysis (IPA).

RESULTS

Setd7 KD impacted a larger set of genes and caused a higher fold change compared to PEITC treatment. Several signaling pathways were altered particularly inflammation-related TNFR signaling and PTEN/PI3K/AKT signaling by Setd7 KD and PEITC. Interestingly, PEITC and Setd7 KD at a small subset of genes that could be potential molecular targets.

CONCLUSION

This study offers new insights into the mechanisms of action of the epigenetic modifier Setd7 and the effects of PEITC treatment in PCa cells and enhances our understanding of the potential cancer preventive/treatment effects of isothiocyanate compounds such as PEITC in PCa.

Histone Methyltransferase Setd7 Regulates Nrf2 Signaling Pathway by Phenethyl Isothiocyanate and Ursolic Acid in Human Prostate Cancer Cells

SCOPE

This study aims to investigate the role of the epigenetic regulator SET domain-containing lysine methyltransferase 7 (Setd7) in regulating the antioxidant Nrf2 pathway in prostate cancer (PCa) cells and examines the effects of two phytochemicals, phenethyl isothiocyanate (PEITC) and ursolic acid (UA).

METHODS AND RESULTS

Lentivirus-mediated shRNA knockdown of Setd7 in LNCaP and PC-3 cells decreases the expression of downstream Nrf2 targets, such as NAD(P)H: quinone oxidoreductase 1 (Nqo1) and glutathione S-transferase theta 2 (Gstt2). Downregulation of Setd7 decreases soft agar colony formation ability of PCa cells. Knockdown of Setd7 increases reactive oxygen species (ROS) generation. Furthermore, Setd7 knockdown attenuates Nqo1 and Gstt2 expression in response to H2 O2 challenge, whereas increased DNA damage is observed in Setd7 knockdown cells in comet assay. Interestingly, Setd7 expression could be induced by the dietary phytochemicals PEITC and UA. Chromatin immunoprecipitation (ChIP) assays show that Setd7 knockdown decreased H3K4me1 enrichment in the Nrf2 and Gstt2 promoter regions, while PEITC and UA treatments elevated the enrichment.

CONCLUSION

Taken together, these results indicate that Setd7 knockdown decreases Nrf2 and Nrf2-target genes expression and that PEITC and UA induce Setd7 expression, which activates the Nrf2/antioxidant response element (ARE) signaling pathway and protects DNA from oxidative damage.

Setd7 and its contribution to Boron-induced bone regeneration in Boron-mesoporous bioactive glass scaffolds

Boron (B), a trace element found in the human body, plays an important role for health of bone by promoting the proliferation and differentiation of osteoblasts. Our research group previously fabricated B-mesoporous bioactive glass (MBG) scaffolds, which successfully promoted osteogenic differentiation of osteoblasts when compared to pure MBG scaffolds without boron. However, the mechanisms of the positive effect of B-MBG scaffolds on osteogenesis remain unknown. Therefore, we performed in-vivo experiments in OVX rat models with pure MBG scaffolds and compared them to B-MBG scaffold. As a result, we found that B-MBG scaffold induced more new bone regeneration compared to pure MBG scaffold and examined genes related to bone regeneration induced by B-MBG scaffold through RNA-seq to obtain target genes and epigenetic mechanisms. The results demonstrated an increased expression and affiliation of Setd7 in the B-MBG group when compared to the MBG group. Immunofluorescent staining from our in vivo samples further demonstrated a higher localization of Setd7 and H3K4me3 in Runx2-positive cells in defects treated with B-MBG scaffolds. KEGG results suggested that specifically Wnt/β-catenin signaling pathway was highly activated in new bone area associated with B-MBG scaffolds. Thereafter, in vitro studies with human bone marrow stem cells (hBMSCs) stimulated by extracted liquid of B-MBG scaffolds was associated with significantly elevated levels of Setd7, as well as H3K4me3 when compared to MBG scaffolds alone. To verify the role of Setd7 in new bone formation in the presence of Boron, Setd7 was knocked down in hBMSCs with stimulation of the extracted liquids of B-MBG or MBG scaffolds. The result showed that osteoblast differentiation of hBMSCs was inhibited when Setd7 was knocked down, which could not be rescued by the extracted liquids of B-MBG scaffolds confirming its role in osteoblast differentiation and bone regeneration. As a histone methylase, Setd7 may be expected to be a potential epigenetic target for new treatment schemes of osteoporosis.

STATEMENT OF SIGNIFICANCE

Boron-containing MBG scaffold has already been proved to promote bone regeneration in femoral defects of OVX rats by our research group, however, the epigenetic mechanism of Boron's positive effects on bone generation remains ill-informed. In our present study, we found an increased expression and affiliation of Setd7 and H3K4me3 in Runx2-positive osteoblasts in vivo. And in vitro, the higher expression of Setd7 enhanced osteogenic differentiation of human BMSCs stimulated by extracted liquids of B-MBG scaffold compared to MBG scaffold, which was associated with the activation of Wnt/β-catenin signaling pathway. Above all, it suggests that Setd7 plays an positive role in osteogenic differentiation and it may become a potential epigenetic target for new schemes for osteoporosis.