OPG/RANKL/RANK gene methylation among alcohol-induced femoral head necrosis in northern Chinese men

Elevated tissue expression of RANKL and RANK is associated with poorer survival rates in pancreatic cancer patients

Pancreatic cancer is a highly lethal malignancy with a growing incidence reported worldwide. Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer, which is often diagnosed at advanced stages, making its prognosis and medical management difficult. The identification of histopathological biomarkers has allowed a more precise stratification of pancreatic cancer patients, providing additional information about their prognosis and offering possible therapeutic targets to be explored. The prognostic value of the receptor activator of nuclear factor-kappa B (RANK) and its ligand (RANKL) has been evaluated in breast and prostate tumors, however, their usefulness has not been assessed in pancreatic cancer. In the present work, we analyzed the relationship between the protein expression of RANK and RANKL with the survival of 41 patients with pancreatic cancer followed for 60 months, by performing immunohistochemistry and Kaplan-Meier curves. Our results demonstrate a direct association of high expression levels of RANK and RANKL with poorer survival of pancreatic cancer patients in comparison to those with low/medium and null expression levels of both markers. Further studies should be conducted to explore the carcinogenic role of both components in this type of tumor, as well as additional promising translational uses.

The Effects of Acute and Chronic Alcohol Administration and Withdrawal on Bone Microstructure, Mechanical Strength, and Remodeling Protein Expression and Their Relation to an Antioxidant and FGF23 In Vivo

Alcohol's detrimental effects on bone health are well established, yet some literature suggests moderate consumption may offer benefits. With alcohol use on the rise, we investigate the impact of acute and chronic alcohol administration, along with withdrawal, on male Wistar rat femurs. We observed a transient cortical thickness increase with acute alcohol (AA) compared to chronic exposure (CA) but no significant changes in trabecular parameters or mechanical properties. High osteocalcin and osteopontin expression levels were noted in AA, alongside elevated RANKL expression. Conversely, CA showed low TRAP levels. FGF23 expression significantly increased during alcohol withdrawal (AW), while GPX decreased after chronic exposure but rose during withdrawal. Although mechanical strength changes were insignificant, biochemical shifts suggest alcohol exposure promotes bone resorption, reduces antioxidant protection, and potentially hampers active vitamin D and phosphate reabsorption via FGF23 upregulation.

Effects of external environment on promoter methylation of PIK3R5 and related pathway regulation in steroid-induced femoral head necrosis

BACKGROUND

Steroid-induced Avascular Necrosis of the Femoral Head (SANFH) is a condition characterized by the necrosis of the femoral head caused by long-term or high-dose hormone usage. Studies have shown that the PI3K/AKT pathway plays a crucial regulatory role in the development of SANFH. The aim of this study is to determine how external environmental factors induce changes in endogenous hormone levels, how these changes lead to steroid-induced femoral head necrosis, and the interrelationship between the changes in PIK3R5 promoter methylation levels and the regulation of the associated signaling pathways.

METHODS

Femoral head samples underwent molecular sequencing analysis. Candidate genes were screened by differential gene analysis and functional enrichment analysis.Methylation level of candidate gene PIK3R5 was verified by methylation-specific PCR(MS-PCR). SANFH model was constructed in New Zealand white rabbits, and the model results were verified by magnetic resonance imaging (MRI) and haematoxylin-eosin (HE) staining.The expression of PIK3R5, PI3K and AKT in rabbit models and human specimens was verified by real-time fluorescence quantitative PCR(RT-qPCR) and Western Blot(WB), respectively.

RESULTS

Human femoral head sequencing results indicate distinct differences in the methylation level and mRNA expression of PIK3R5 in SANFH. MS-PCR results showed the methylation level of SANFH patients was significantly higher than that of the control group (P < 0.01). The RT-qPCR results showed that PIK3R5 and PI3K expression levels in the SANFH group were lower than those in the control group (P < 0.05), and the WB experiment results were consistent with the RT-qPCR results. The MRI and HE staining results showed that the rabbit model of SANFH was successfully constructed, and the results of RT-qPCR and WB were consistent with the results of human tissues.

CONCLUSION

During the occurrence and development of SANFH, PIK3R5 gene regulates the PI3K/AKT pathway through methylation modification, promotes the oxidative stress response of cells, and accelerates the disease process.

Effect of Aerobic/Strength Training on RANKL Gene DNA Methylation Levels

BACKGROUND

The osteoclastogenesis RANKL gene plays a key role in bone remodeling. The hypomethylation of its promoter region may cause osteoporosis. The present study aimed to elucidate the influence of physical activity on DNA methylation changes of RANKL promoter cytosine-phosphate-guanine (CpG)-rich region in active and sedentary adults and to assess the effect of aerobic and strength training on RANKL DNA methylation changes among Tunisian-North African adults.

METHODS

A total of 104 participants including 52 adults (58% males and 42% females) and 52 adults (31% males and 69% females) were recruited for the observational and interventional part of the study, respectively. The intervention consisted of 12 weeks of aerobic training (30 min/session) followed by 10 minutes of strengthening exercises. All participants completed the International Physical Activity Questionnaire and provided blood samples for quantitative methylation-specific polymerase chain reaction (PCR) analysis.

RESULTS

The study revealed a significant difference (P = 6 × 10-10) in the methylation level of the RANKL promoter region between active and sedentary adults, with a 6.68-fold increase observed in the active group. After the intervention, both the trained (P = 41 × 10-5) and untrained (P = .002) groups displayed high methylation levels in the RANKL promoter region. In addition, the trained group exhibited significant improvements in heart rate (P = 2.2 × 10-16), blood pressure (P = 39 × 10-3), maximal oxygen uptake (P = 1.5 × 10-7), and fat mass (P = 7 × 10-4).

CONCLUSION

Exploring epigenetic modifications in the RANKL promoter region may contribute to a more comprehensive understanding of the complexity of osteoporosis. This suggests that aerobic/strength training could potentially improve the bone system, reducing its vulnerability to osteoporosis by increasing RANKL DNA methylation.

Multigenerational genetic effects of paternal cadmium exposure on ovarian granulosa cell apoptosis

To explore whether paternal cadmium (Cd) exposure causes ovarian granulosa cell (GC) apoptosis in offspring and the multigenerational genetic effects. From postnatal day 28 (PND28) until adulthood (PND56), SPF male Sprague-Dawley (SD) rats were gavaged daily with varying concentrations of CdCl_2. (0, 0.5, 2, and 8 mg/kg). After treatment, the F1 generation was produced by mating with untreated female rats, and the F1 generation male rats were mated with untreated female rats to produce the F2 generation. Apoptotic bodies (electron microscopy) and significantly higher apoptotic rates (flow cytometry) were observed in both F1 and F2 ovarian GCs following paternal Cd exposure. Moreover, the mRNA (qRTPCR) or protein (Western blotting) levels of bax, bcl2, bcl-xl, caspase 3, caspase 8, and caspase 9 were changed to varying degrees. Apoptosis-related miRNAs (qRTPCR) and methylation modifications of apoptosis-related genes (bisulfite-sequencing PCR) in ovarian GCs were further detected. Compared with those of controls, the expression patterns of miRNAs in F1 and F2 offspring were different after paternal Cd exposure, while the average methylation level of apoptosis-related genes did not change significantly (except for individual loci). In summary, there are paternal genetic intergenerational and transgenerational effects on ovarian GC apoptosis induced by paternal Cd exposure. These genetic effects were related to the upregulation of BAX, BCL-XL, Cle-CASPASE 3, and Cle-CASPASE 9 in F1 and the upregulation of Cle-CASPASE 3 in F2 progeny. Important changes in apoptosis-related miRNAs were also observed.

Gadus morhua Eggs Sialoglycoprotein Prevent Estrogen Deficiency-Induced High Bone Turnover by Controlling OPG/RANKL/TRAF6 Pathway and Serum Metabolism

In recent years, the development of safe and effective anti-osteoporosis factors has attracted extensive attention. In this study, an estrogen-deficient osteoporosis rat model was employed to study the improving mechanism of sialoglycoprotein isolated from Gadus morhua eggs (Gds) against osteoporosis. The results showed that compared with OVX, Gds ameliorated the trabecular microstructure, especially the increased trabecular thickness, decreased trabecular separation, and enhanced the trabecular number. The analysis of qRT-PCR and western blotting found that Gds reduced bone resorption by inhibiting RANKL-induced osteoclastogenesis. The LC-MS/MS was used to investigate serum metabolism, and the enrichment metabolites were analyzed by the KEGG pathway. The results revealed that the Gds significantly altered the fat anabolism pathway, which includes ovarian steroidogenesis pathway and arachidonic acid metabolism pathway. Altogether, Gds could improve osteoporosis by suppressing high bone turnover via controlling OPG/RANKL/TRAF6 pathway, which is implicated with ovarian steroidogenesis pathway and arachidonic acid metabolism pathway. These findings indicated that Gds could be a candidate factor for anti-osteoporosis.