Biofluid GPNMB/osteoactivin as a potential biomarker of ageing: A cross-sectional study.

Background: Glycoprotein non-metastatic melanoma B (GPNMB)/osteoactivin was first identified in the human melanoma cell lines. GPNMB plays a key role in the anti-inflammatory and antioxidative functions as well as osteoblast differentiation, cancer progression, and tissue regeneration. Recently, GPNMB was used as an anti-aging vaccine for mice. The present study aimed to investigate the potential of biofluid GPNMB as an aging biomarker in humans using serum and urine samples from an aging Chinese population. Methods: We analyzed RNA-sequencing data (GSE132040) from 17 murine organs across different ages to assess the gene expression of potential ageing biomarkers. Spearman's correlation coefficients were used to evaluate the relationship between gene expression and age. Meanwhile, a cross-sectional population study was conducted, which included 473 participants (aged 25-91 years), a representative subset of participants from the Peng Zu Study on Healthy Ageing in China (Peng Zu Cohort). Biofluid GPNMB levels were measured by ELISA. The associations of serum and urine GPNMB levels with various clinical and anthropometrical indices were assessed using ANOVA, Kruskal-Wallis H test, and univariate and multivariate linear regression analyses. Results: In mice, the Gpnmb mRNA expression levels showed a significant positive association with age in multiple organs in mice (P < 0.05). In Peng Zu Cohort, biofluid (both serum and urine) GPNMB levels showed a positive correlation with age (P < 0.05). Univariate linear regression analysis revealed that serum GPNMB levels were negatively associated with skeletal muscle mass index (SMI, P < 0.05) and insulin-like growth factor 1 (IGF-1, P < 0.05), and urine GPNMB levels showed a negative association with total bile acids (TBA, P < 0.05). Multivariate linear regression analysis further indicated that serum GPNMB levels negatively correlated with the systemic immune-inflammation index (SII, P < 0.05), and the urine GPNMB levels maintained a negative association with TBA (P < 0.05), additionally, urine GPNMB levels in men were significantly lower than in women (P < 0.05). Conclusions: The biofluid GPNMB was a strong clinical biomarker candidate for estimating biological aging.

A modified nucleoside O6-methyl-2'-deoxyguanosine-5'-triphosphate exhibits anti-glioblastoma activity in a caspase-independent manner.

Resistance to temozolomide (TMZ), the frontline chemotherapeutic agent for glioblastoma (GBM), has emerged as a formidable obstacle, underscoring the imperative to identify alternative therapeutic strategies to improve patient outcomes. In this study, we comprehensively evaluated a novel agent, O6-methyl-2'-deoxyguanosine-5'-triphosphate (O6-methyl-dGTP) for its anti-GBM activity both in vitro and in vivo. Notably, O6-methyl-dGTP exhibited pronounced cytotoxicity against GBM cells, including those resistant to TMZ and overexpressing O6-methylguanine-DNA methyltransferase (MGMT). Mechanistic investigations revealed that O6-methyl-dGTP could be incorporated into genomic DNA, disrupting nucleotide pools balance, and inducing replication stress, resulting in S-phase arrest and DNA damage. The compound exerted its anti-tumor properties through the activation of AIF-mediated apoptosis and the parthanatos pathway. In vivo studies using U251 and Ln229 cell xenografts supported the robust tumor-inhibitory capacity of O6-methyl-dGTP. In an orthotopic transplantation model with U87MG cells, O6-methyl-dGTP showcased marginally superior tumor-suppressive activity compared to TMZ. In summary, our research, for the first time, underscores the potential of O6-methyl-dGTP as an effective candidate against GBM, laying a robust scientific groundwork for its potential clinical adoption in GBM treatment regimens.

Serum glycoprotein non-metastatic melanoma protein B (GPNMB) level as a potential biomarker for diabetes mellitus-related cataract: A cross-sectional study.

Background: Diabetes mellitus (DM), a metabolic disease that has attracted significant research and clinical attention over the years, can affect the eye structure and induce cataract in patients diagnosed with DM. Recent studies have indicated the relationship between glycoprotein non-metastatic melanoma protein B (GPNMB) and DM and DM-related renal dysfunction. However, the role of circulating GPNMB in DM-associated cataract is still unknown. In this study, we explored the potential of serum GPNMB as a biomarker for DM and DM-associated cataract. Methods: A total of 406 subjects were enrolled, including 60 and 346 subjects with and without DM, respectively. The presence of cataract was evaluated and serum GPNMB levels were measured using a commercial enzyme-linked immunosorbent assay kit. Results: Serum GPNMB levels were higher in diabetic individuals and subjects with cataract than in those without DM or cataract. Subjects in the highest GPNMB tertile group were more likely to have metabolic disorder, cataract, and DM. Analysis performed in subjects with DM elucidated the correlation between serum GPNMB levels and cataract. Receiver operating characteristic (ROC) curve analysis also indicated that GPNMB could be used to diagnose DM and cataract. Multivariable logistic regression analysis illustrated that GPNMB levels were independently associated with DM and cataract. DM was also found to be an independent risk factor for cataract. Further surveys revealed the combination of serum GPNMB levels and presence of DM was associated with a more precise identification of cataract than either factor alone. Conclusions: Increased circulating GPNMB levels are associated with DM and cataract and can be used as a biomarker of DM-associated cataract.

Increased systemic RNA oxidative damage and diagnostic value of RNA oxidative metabolites during Shigella flexneri-induced intestinal infection.

BACKGROUND: Shigella flexneri (S. flexneri) is a major pathogen causing acute intestinal infection, but the systematic oxidative damage incurred during the course of infection has not been investigated. AIM: To investigate the incurred systemic RNA oxidative damage and the diagnostic value of RNA oxidative metabolites during S. flexneri-induced intestinal infection. METHODS: In this study, a Sprague-Dawley rat model of acute intestinal infection was established by oral gavage with S. flexneri strains. The changes in white blood cells (WBCs) and cytokine levels in blood and the inflammatory response in the colon were investigated. We also detected the RNA and DNA oxidation in urine and tissues. RESULTS: S. flexneri infection induced an increase in WBCs, C-reactive protein, interleukin (IL)-6, IL-10, IL-1ß, IL-4, IL-17a, IL-10, and tumor necrosis factor α (TNF-α) in blood. Of note, a significant increase in urinary 8-oxo-7,8-dihydroguanosine (8-oxo-Gsn), an important marker of total RNA oxidation, was detected after intestinal infection (P = 0.03). The urinary 8-oxo-Gsn level returned to the baseline level after recovery from infection. In addition, the results of a correlation analysis showed that urinary 8-oxo-Gsn was positively correlated with the WBC count and the cytokines IL-6, TNF-α, IL-10, IL-1ß, and IL-17α. Further detection of the oxidation in different tissues showed that S. flexneri infection induced RNA oxidative damage in the colon, ileum, liver, spleen, and brain. CONCLUSION: Acute infection induced by S. flexneri causes increased RNA oxidative damage in various tissues (liver, spleen, and brain) and an increase of 8-oxo-Gsn, a urinary metabolite. Urinary 8-oxo-Gsn may be useful as a biomarker for evaluating the severity and prognosis of infection.

The high expression of MTH1 and NUDT5 promotes tumor metastasis and indicates a poor prognosis in patients with non-small-cell lung cancer.

MutT Homolog 1 (MTH1) is a mammalian 8-oxodGTPase for sanitizing oxidative damage to the nucleotide pool. Nudix type 5 (NUDT5) also sanitizes 8-oxodGDP in the nucleotide pool. The role of MTH1 and NUDT5 in non-small-cell lung cancer (NSCLC) progression and metastasis remains unclear. In the present study, we reported that MTH1 and NUDT5 were upregulated in NSCLC cell lines and tissues, and higher levels of MTH1 or NUDT5 were associated with tumor metastasis and a poor prognosis in patients with NSCLC. Their suppression also restrained tumor growth and lung metastasis in vivo and significantly inhibited NSCLC cell migration, invasion, cell proliferation and cell cycle progression while promoting apoptosis in vitro. The opposite effects were observed in vitro following MTH1 or NUDT5 rescue. In addition, the upregulation of MTH1 or NUDT5 enhanced the MAPK pathway and PI3K/AKT activity. Furthermore, MTH1 and NUDT5 induce epithelial-mesenchymal transition both in vitro and in vivo. These results highlight the essential role of MTH1 and NUDT5 in NSCLC tumor tumorigenesis and metastasis as well as their functions as valuable markers of the NSCLC prognosis and potential therapeutic targets.