Typing characteristics of metabolism-related genes in osteoporosis.

Objective: Osteoporosis is a common musculoskeletal disease. Fractures caused by osteoporosis place a huge burden on global healthcare. At present, the mechanism of metabolic-related etiological heterogeneity of osteoporosis has not been explored, and no research has been conducted to analyze the metabolic-related phenotype of osteoporosis. This study aimed to identify different types of osteoporosis metabolic correlates associated with underlying pathogenesis by machine learning. Methods: In this study, the gene expression profiles GSE56814 and GSE56815 of osteoporosis patients were downloaded from the GEO database, and unsupervised clustering analysis was used to identify osteoporosis metabolic gene subtypes and machine learning to screen osteoporosis metabolism-related characteristic genes. Meanwhile, multi-omics enrichment was performed using the online Proteomaps tool, and the results were validated using external datasets GSE35959 and GSE7429. Finally, the immune and stromal cell types of the signature genes were inferred by the xCell method. Results: Based on unsupervised cluster analysis, osteoporosis metabolic genotyping can be divided into three distinct subtypes: lipid and steroid metabolism subtypes, glycolysis-related subtypes, and polysaccharide subtypes. In addition, machine learning SVM identified 10 potentially metabolically related genes, GPR31, GATM, DDB2, ARMCX1, RPS6, BTBD3, ADAMTSL4, COQ6, B3GNT2, and CD9. Conclusion: Based on the clustering analysis of gene expression in patients with osteoporosis and machine learning, we identified different metabolism-related subtypes and characteristic genes of osteoporosis, which will help to provide new ideas for the metabolism-related pathogenesis of osteoporosis and provide a new direction for follow-up research.

Reversing impact of phytoplankton phosphorus limitation on coastal hypoxia due to interacting changes in surface production and shoreward bottom oxygen influx.

Phosphorus (P) limitation of phytoplankton growth is increasingly common in estuarine and coastal waters due to rising anthropogenic nitrogen input faster than that of phosphorus. However, the impact of P limitation on coastal hypoxia remains inconclusive and is challenging to observe. By combining observations with results from a three-dimensional physical-biogeochemical model off the Pearl River Estuary, we illustrate that during the summer upwelling period, the impact of P limitation reverses from suppressing hypoxia to amplifying hypoxia as P-limitation severity decreases. When P limitation is severe in the ecosystem (i.e., P limitation extensively covers the stratified waters where hypoxia tends to develop), the surface primary production and the coupled bottom oxygen consumption are diluted along the upstream-downstream axis because of the P limitation. In addition, the increased downstream bottom oxygen level enhances the shoreward bottom oxygen influx. These effects, together, reduce coastal hypoxia. In contrast, when P-limitation severity is low (i.e., P limitation is spatially constrained), the downstream relocated surface production reduces upstream hypoxia but increases downstream hypoxia, which subsequently weakens the shoreward bottom oxygen influx and hence lowers its capacity to relieve upstream hypoxia. The net effect can amplify the coastal hypoxic extent. Our results emphasize how different P-limitation severity can reverse its impact on coastal hypoxia due to the interacting changes in surface production and bottom oxygen influx. We propose the potential of using the spatial extent of P limitation as a proxy to predict its impact on coastal hypoxia and support ecosystem nutrient management.

Mitigation of Eutrophication and Hypoxia through Oyster Aquaculture: An Ecosystem Model Evaluation off the Pearl River Estuary.

Shellfish aquaculture has been proposed to abate eutrophication because it can remove nutrients via shellfish filter-feeding. Using a three-dimensional physical-biogeochemical model, we investigate how effective oyster aquaculture can alleviate eutrophication-driven hypoxia off the Pearl River Estuary. Results show that oysters reduce sediment oxygen consumption and thus hypoxia, by reducing both particulate organic matter directly and regenerated nutrients that support new production of organic matter. The hypoxia reduction is largest when oysters are farmed within the upper water of the low-oxygen zone, and the reduction increases with increasing oyster density although oyster growth becomes slower due to food limitation. When oysters are farmed upstream of the hypoxic zone, the farming-induced hypoxia reduction is small and it declines with increasing oyster density because the nutrients released from the farm can increase downstream organic matter production. An oyster farming area of 10 to 200 km2 yields a hypoxic volume reduction of 10% to 78%, equaling the impact of reducing 10% to 60% of river nutrient input. Our results demonstrate that oyster aquaculture can mitigate eutrophication and hypoxia, but its effectiveness depends on the farming location, areal size, and oyster density, and optimal designs must take into account the circulation and biogeochemical characteristics of the specific ecosystem.

Dihydrotanshinone I Alleviates Spinal Cord Injury via Suppressing Inflammatory Response, Oxidative Stress and Apoptosis in Rats.

BACKGROUND Spinal cord injury (SCI) is a serious nervous system injury, causing extremely low quality of life and immensurable economic losses. However, there is few therapies that can effectively cure the injury. The goal of the present study was to explore the potential therapeutic effects of dihydrotanshinone I (DI) for SCI and the involving mechanism. MATERIAL AND METHODS A SCI rat model was structured to investigate the effects of DI on recovery of SCI. Tarlov's scale was employed to assess the neuronal function and histopathological examination was carried out by hematoxylin and eosin staining. In addition, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-1ß, inducible nitric oxide synthase (iNOS), total oxidant status (TOS) and total antioxidant status (TAS) levels were detected. Tunel assay and western blot analysis were performed to evaluate cell apoptosis. Furthermore, western blot assay was used to measure the protein expressions. RESULTS The results demonstrated that the treatment of DI alleviated the pathological damage induced by SCI and promoted the neuronal functional recovery. DI suppressed TNF-alpha, IL-1ß, IL-6, iNOS, and TOS levels while improved the TAS level. Moreover, increased cell apoptosis in SCI rats was inhibited by administration of DI. Most importantly, DI reserved the soaring of TLR4, MyD88, HMGB1, and NOX4 level after induction of SCI. Thus, the observation revealed that the HMGB1/TLR4/NOX4 pathway may be involved in the protective effects of DI on SCI. CONCLUSIONS In conclusion, the findings suggest that DI alleviates SCI by restraining secretion of inflammatory factors, and occurrence of oxidative stress and apoptosis in vivo. DI may be developed into an effective alternative therapy for SCI in clinic.

Elevated Contribution of Low Nucleic Acid Prokaryotes and Viral Lysis to the Prokaryotic Community Along the Nutrient Gradient From an Estuary to Open Ocean Transect.

Prokaryotes represent the largest living biomass reservoir in aquatic environments and play a crucial role in the global ocean. However, the factors that shape the abundance and potential growth rate of the ecologically distinct prokaryotic subgroups [i.e., high nucleic acid (HNA) and low nucleic acid (LNA) cells] along varying trophic conditions in the ocean remain poorly understood. This study conducted a series of modified dilution experiments to investigate how the abundance and potential growth rate of HNA and LNA prokaryotes and their regulating factors (i.e., protozoan grazing and viral lysis) change along a cross-shore nutrient gradient in the northern South China Sea. The results showed that the abundance of both HNA and LNA cells was significantly positively correlated with the abundance of heterotrophic nanoflagellates and viruses, whereas only HNA abundance exhibited a significant positive correlation with nutrient level. With a decreasing nutrient concentration, the potential growth rate of the HNA subgroup declined significantly, while that of the LNA subgroup was significantly enhanced, leading to an elevated relative potential growth rate of the LNA to HNA subgroup under decreasing nutrient levels. Furthermore, our data revealed different regulatory roles of protozoan grazing and viral lysis on the HNA and LNA subgroups, with HNA suffering higher mortality pressure from grazing than from lysis in contrast to LNA, which experienced equivalent pressures. As the nutrient levels declined, the relative contribution of lysis to the mortality of the HNA subgroup increased significantly, in contrast to the insignificant change in that of the LNA subgroup. Our results indicated the elevated role of LNA cells in the prokaryotic community and the enhanced viral lysis pressure on the total prokaryotes under oligotrophic conditions. This implies a weakened efficiency of carbon cycling within the microbial loop and enhanced viral lysis to shunt more carbon and energy flow in the future ocean, in which oligotrophication will be strengthened due to global warming.

Bioavailability of Polycyclic Aromatic Hydrocarbons and their Potential Application in Eco-risk Assessment and Source Apportionment in Urban River Sediment.

Traditional risk assessment and source apportionment of sediments based on bulk polycyclic aromatic hydrocarbons (PAHs) can introduce biases due to unknown aging effects in various sediments. We used a mild solvent (hydroxypropyl-ß-cyclodextrin) to extract the bioavailable fraction of PAHs (a-PAHs) from sediment samples collected in Pearl River, southern China. We investigated the potential application of this technique for ecological risk assessments and source apportionment. We found that the distribution of PAHs was associated with human activities and that the a-PAHs accounted for a wide range (4.7%-21.2%) of total-PAHs (t-PAHs), and high risk sites were associated with lower t-PAHs but higher a-PAHs. The correlation between a-PAHs and the sediment toxicity assessed using tubificid worms (r = -0.654, P = 0.021) was greater than that from t-PAH-based risk assessment (r = -0.230, P = 0.472). Moreover, the insignificant correlation between a-PAH content and mPEC-Q of low molecular weight PAHs implied the potential bias of t-PAH-based risk assessment. The source apportionment from mild extracted fractions was consistent across different indicators and was in accordance with typical pollution sources. Our results suggested that mild extraction-based approaches reduce the potential error from aging effects because the mild extracted PAHs provide a more direct indicator of bioavailability and fresher fractions in sediments.