Glucocorticoid Receptor Regulates TNFSF11 Transcription by Binding to Glucocorticoid Responsive Element in TNFSF11 Proximal Promoter Region

USP10-mediated deubiquitination of NR3C1 regulates bone homeostasis by controlling CST3 expression

Dysregulated bone homeostasis contributes to multiple diseases including osteoporosis (OP). In this study, osteoporotic mice were successfully generated using ovariectomy to investigate the role of nuclear receptor subfamily 3 group C member 1 (NR3C1) in OP. NR3C1, identified as a significantly upregulated gene in OP using bioinformatic tools, was artificially downregulated in osteoporotic mice. NR3C1 expression was significantly elevated in the femoral tissues of osteoporotic patients, and downregulation of NR3C1 alleviated bone loss and restored bone homeostasis in osteoporotic mice, as manifested by increased ALP- and OCN-positive cells and reduced RANKL/OPG ratio. Downregulation of NR3C1 inhibited osteoclastic differentiation of RAW264.7 cells and mouse bone marrow-derived macrophages (BMDM) and promoted osteogenic differentiation of MC3T3-E1 cells. The transcription factor NR3C1 bound to the cystatin-3 (CST3) promoter to repress its transcription in both RAW264.7 and MC3T3-E1 cells. The downregulation of CST3 reversed the protective effect of NR3C1 downregulation against OP. Ubiquitin-specific-processing protease 10 (USP10)-mediated deubiquitination of NR3C1 improved NR3C1 stability. Downregulation of USP10 inhibited osteoclastic differentiation of RAW264.7 cells and BMDM while promoting osteogenic differentiation of MC3T3-E1 cells. Taken together, USP10-mediated deubiquitination of NR3C1 regulates bone homeostasis by controlling CST3 transcription, providing an attractive therapeutic strategy to alleviate OP.

Changes in RANKL, OPG, and 25(OH)D Levels in Children with Leukemia from Diagnosis to Remission

BACKGROUND

The receptor activator of the nuclear factor-kB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) pathway is a determining pathway in the balance between bone formation and resorption, and disruptions in this complex can affect bone metabolism.

METHODS

This study analyzes the changes in RANKL, OPG, and 25(OH)D levels; the RANKL/OPG ratio; and other bone turnover markers (BTMs) from diagnosis to complete remission in children with acute lymphoblastic leukemia (ALL). This is a prospective observational cohort study, carried out at the Instituto Mexicano del Seguro Social, Mexico City, including 33 patients (4-17 years) with newly diagnosed B-cell ALL. The patients were treated with the HP09 chemotherapy protocol. Children who had previously been treated with corticosteroids were excluded. A peripheral blood sample at diagnosis and remission was collected to determine the 25(OH)D and BTM concentrations.

RESULTS

Increased RANKL (p = 0.001) and osteocalcin (p < 0.001) levels and RANKL/OPG ratio (<0.001) and a decreased OPG level (p = 0.005) were observed at remission, predominantly in the high-risk (HR) relapse and vitamin D deficiency groups. A negative association between RANKL and OPG (r = -0.454, p = 0.008) was observed.

CONCLUSIONS

we suggest that the RANKL/OPG ratio could serve as a bone remodeling marker in ALL patients.

Zuogui Pill Ameliorates Glucocorticoid-Induced Osteoporosis through ZNF702P-Based ceRNA Network: Bioinformatics Analysis and Experimental Validation

Glucocorticoid-induced osteoporosis (GIOP) is a musculoskeletal disease with increased fracture risk caused by long-term application of glucocorticoid, but there exist few effective interventions. Zuogui Pill (ZGP) has achieved clinical improvement for GIOP as an ancient classical formula, but its molecular mechanisms remain unclear due to scanty relevant studies. This study aimed to excavate the effective compounds and underlying mechanism of ZGP in treating GIOP and construct relative ceRNA network by using integrated analysis of bioinformatics analysis and experimental validation. Results show that ZNF702P is significantly upregulated in GIOP than normal cases based on gene chip sequencing analysis. Totally, 102 ingredients and 535 targets of ZGP as well as 480 GIOP-related targets were selected, including 122 common targets and 8 intersection targets with the predicted mRNAs. The ceRNA network contains one lncRNA (ZNF702P), 6 miRNAs, and 8 mRNAs. Four hub targets including JUN, CCND1, MAPK1, and MAPK14 were identified in the PPI network. Six ceRNA interaction axes including ZNF702P-hsa-miR-429-JUN, ZNF702P-hsa-miR-17-5p/hsa-miR-20b-5p-CCND1, ZNF702P-hsa-miR-17-5p/hsa-miR-20b-5p-MAPK1, and ZNF702P-hsa-miR-24-3p-MAPK14 were obtained. By means of molecular docking, we found that all the hub targets could be effectively combined with related ingredients. GO enrichment analysis showed 649 biological processes, involving response to estrogen, response to steroid hormone, inflammatory response, macrophage activation, and osteoclast differentiation, and KEGG analysis revealed 102 entries with 36 relative signaling pathways, which mainly contained IL-17 signaling pathway, T cell receptor signaling pathway, FoxO signaling pathway, the PD-L1 expression and PD-1 checkpoint pathway, MAPK signaling pathway, TNF signaling pathway, Estrogen signaling pathway, and Wnt signaling pathway. Our experiments confirmed that ZNF702P exhibited gradually increasing expression levels during osteoclast differentiation of human peripheral blood monocytes (HPBMs) induced by RANKL, while ZGP could inhibit osteoclast differentiation of HPBMs induced by RANKL in a concentration-dependent manner. Therefore, by regulating inflammatory response, osteoclast differentiation, and hormone metabolism, ZGP may treat GIOP by regulating hub target genes, such as JUN, CCND1, MAPK1, and MAPK14, and acting on numerous key pathways, which involve the ZNF702P-based ceRNA network.

Stimulation of osteoclast formation and bone resorption by glucocorticoids: Synergistic interactions with the calcium regulating hormones parathyroid hormone and 1,25(OH)2-vitamin D3

Osteoporosis is a significant health problem, with skeletal fractures increasing morbidity and mortality. Excess glucocorticoids (GC) represents the leading cause of secondary osteoporosis. The first phase of glucocorticoid-induced osteoporosis is increased bone resorption. In this Chapter, in vitro studies of the direct glucocorticoid receptor (GR) mediated cellular effects of GC on osteoclasts to affect bone resorption and indirect effects on osteoblast lineage cells to increase the RANKL/OPG ratio and stimulate osteoclastogenesis and bone resorption are reviewed in detail, together with detailed descriptions of in vivo effects of GC in different portions of the skeleton in research animals and humans. Brief sections are devoted to contrasting functions of GC in osteonecrosis, vitamin D formation, in vitro and in vivo bone resorptive actions dependent on vitamin D receptor and vitamin D toxicity, as well as the molecular basis of GR action. Included are also more detailed assessments of the interactions of GC with the major calcium regulating hormones, 1,25(OH)₂-vitamin D3 and parathyroid hormone, describing the in vitro increases in RANKL/OPG ratios, osteoclastogenesis and synergistic bone resorption that occurs when GC is combined with either 1,25(OH)₂-vitamin D3 or parathyroid hormone. Additionally, a molecular basic for the synergistic interaction of GC with 1,25(OH)₂-vitamin D3 is provided along with a suggested molecular basic for the interaction between GC and parathyroid hormone.

Midkine promotes breast cancer cell proliferation and migration by upregulating NR3C1 expression and activating the NF-κB pathway

BACKGROUND

Breast cancer (BC) is the most common malignancy in females and is the second leading cause of cancer-related death among women worldwide. Midkine (MDK) is a heparin-binding growth factor that is abnormally expressed at high levels in various human malignancies. We aimed to uncover the biological function and molecular mechanism of MDK in BC cells.

METHODS AND RESULTS

MDA-MB-231-shMDK and T47D-shMDK BC cells were established. The in vitro biological functions of MDK were demonstrated by CCK-8 assays, Transwell assays and Western blotting, whereas qPCR pathway arrays were implemented to explore the mechanism of MDK in BC cells. Functionally, we verified that silencing MDK significantly suppressed BC cell proliferation and migration by inhibiting the activation of the nuclear factor kappa B (NF-κB) pathway and the nuclear distribution of NF-κB. Meanwhile, Ingenuity Pathway Analysis (IPA) and a qPCR pathway array revealed that silencing MDK decreased the expression of NR3C1, a potential downstream target of the NF-κB pathway. We also confirmed that treatment with an NF-κB inhibitor suppressed NR3C1 expression in BC cells. Finally, we demonstrated that silencing NR3C1 repressed BC cell proliferation and migration.

CONCLUSIONS

Our findings highlight a novel mechanism by which MDK influences BC progression via regulation of the NF-κB-NR3C1 pathway.