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205 result(s) for "Meng, Yichen"
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Spatial variability and source analysis of soil heavy metals: A case study of the key planting area of special agricultural products in Cangxi County, China
Heavy metal pollution in farmland soil represents a considerable risk to ecosystems and human health, constituting a global concern. Focusing on a key area for the cultivation of special agricultural products in Cangxi County, we collected 228 surface soil samples. We analyzed the concentration, spatial distribution, and pollution levels of six heavy metals (Cr, Cu, Pb, Ni, Zn, and Hg) in the soil. Moreover, we investigated the sources and contribution rates of these heavy metals using Principal Component Analysis/Absolute Principal Component Scores (PCA/APCS) and Positive Matrix Factorization (PMF) models. Our findings indicate that none of the six metals exceeded the pollution thresholds for farmland soils. However, the mean concentrations of Cr and Ni surpassed the background levels of Sichuan Province. A moderate spatial correlation existed between Pb and Ni, attributable to both natural and anthropogenic factors, whereas Zn, Cu, Hg, and Cr displayed a strong spatial correlation, mainly due to natural factors. The spatial patterns of Cr, Cu, Zn, Pb, and Ni were similar, with higher concentrations in the northern and eastern regions and lower concentrations centrally. Hg’s spatial distribution differed, exhibiting a broader range of lower values. The single pollution index evaluation showed that Cr and Ni were low pollution, and the other elements were no pollution. The average value of comprehensive pollution index is 0.994, and the degree of pollution is close to light pollution. Predominantly, higher pollution levels in the northern and eastern regions, lower around reservoirs. The PCA/APCS model identified two main pollution sources: agricultural traffic mixed source (65.2%) and natural parent source (17.2%). The PMF model delineated three sources: agricultural activities (32.59%), transportation (30.64%), and natural parent sources (36.77%). Comparatively, the PMF model proved more accurate and reliable, yielding findings more aligned with the study area’s actual conditions.
Endothelial Cell‐Derived Lactate Triggers Bone Mesenchymal Stem Cell Histone Lactylation to Attenuate Osteoporosis
Blood vessels play a role in osteogenesis and osteoporosis; however, the role of vascular metabolism in these processes remains unclear. The present study finds that ovariectomized mice exhibit reduced blood vessel density in the bone and reduced expression of the endothelial glycolytic regulator pyruvate kinase M2 (PKM2). Endothelial cell (EC)‐specific deletion of Pkm2 impairs osteogenesis and worsens osteoporosis in mice. This is attributed to the impaired ability of bone mesenchymal stem cells (BMSCs) to differentiate into osteoblasts. Mechanistically, EC‐specific deletion of Pkm2 reduces serum lactate levels secreted by ECs, which affect histone lactylation in BMSCs. Using joint CUT&Tag and RNA sequencing analyses, collagen type I alpha 2 chain (COL1A2), cartilage oligomeric matrix protein (COMP), ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), and transcription factor 7 like 2 (TCF7L2) as osteogenic genes regulated by histone H3K18la lactylation are identified. PKM2 overexpression in ECs, lactate addition, and exercise restore the phenotype of endothelial PKM2‐deficient mice. Furthermore, serum metabolomics indicate that patients with osteoporosis have relatively low lactate levels. Additionally, histone lactylation and related osteogenic genes of BMSCs are downregulated in patients with osteoporosis. In conclusion, glycolysis in ECs fuels BMSC differentiation into osteoblasts through histone lactylation, and exercise partially ameliorates osteoporosis by increasing serum lactate levels.
A novel DCSTAMP antagonist impedes preosteoclast fusion via modulation of RAP1B–RAC1-mediated cytoskeletal remodeling
DCSTAMP serves as a critical fusogenic protein orchestrating cell–cell fusion during osteoclastogenesis. The disruption of DCSTAMP functionality preserves preosteoclasts, thereby augmenting bone mass through both anabolic and anti-catabolic mechanisms. Despite its therapeutic potential, specific DCSTAMP inhibitors remain undiscovered. Here we used structure-based virtual screening utilizing AlphaFold predictions to identify a novel small molecule, E8431, which selectively targets the endoplasmic domain of DCSTAMP. In vitro investigations confirm E8431’s capacity to impede preosteoclast fusion, concurrently inhibiting bone resorption while stimulating PDGFBB secretion, thus promoting osteogenic and angiogenic processes. We further elucidated a previously uncharacterized DCSTAMP signaling cascade involving DCSTAMP–RAP1B interaction, which activates RAP1–RAC1 signaling-dependent cytoskeletal reorganization. Notably, E8431 demonstrates potent inhibitory effects on this DCSTAMP–RAP1B molecular interface. Moreover, E8431 administration effectively attenuates ovariectomy-induced bone loss in murine models without apparent toxicity, underscoring its potential as a therapeutic agent for osteoporosis. E8431 targets DCSTAMP to enhance bone mass and health This study explores how bone health is maintained and how it can be disrupted, leading to conditions such as osteoporosis. Researchers aimed to find a better treatment by targeting a protein called DCSTAMP, which plays a role in bone cell formation. They used advanced computer models to predict the structure of DCSTAMP and identify potential drugs that could inhibit its function. They tested these drugs in lab experiments and found that E8431 effectively reduced the formation of bone-resorbing cells without harming other cells. E8431 also promote bone formation and blood vessel growth, making it a promising candidate for osteoporosis treatment. E8431 could also offer a new way to treat osteoporosis by addressing multiple aspects of bone health. Future research may focus on refining E8431 for clinical use and exploring its long-term effects. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.
MicroRNA-140-5p regulates osteosarcoma chemoresistance by targeting HMGN5 and autophagy
Chemotherapy is an important treatment modality for osteosarcoma. However, it often fails because of chemoresistance, especially multidrug resistance. Previously, we found several genes were involved in chemoresistance development. In this report, we used high-throughput microRNA (miRNA) expression analysis to reveal that expression of miR-140-5p was associated with chemosensitivity in osteosarcoma. The exact roles of miR-140-5p in the chemoresistance of osteosarcoma were then investigated, we found that knockdown of miR-140-5p enhanced osteosarcoma cells resistance to multiple chemotherapeutics while overexpression of miR-140-5p sensitized tumors to chemotherapy in vitro . Moreover, in vivo , knockdown of miR-140-5p also increased the osteosarcoma cells resistance to chemotherapy. Luciferase assay and Western blot analysis showed that HMGN5 was the direct target of miR-140-5p which could positively regulated autophagy. Silencing these target genes by siRNA or inhibition of autophagy sensitized osteosarcoma cells to chemotherapy. These findings suggest that a miR-140-5p/HMGN5/autophagy regulatory loop plays a critical role in chemoresistance in osteosarcoma. In conclusion, our data elucidated that miR-140-5p promoted autophagy mediated by HMGN5 and sensitized osteosarcoma cells to chemotherapy. These results suggest a potential application of miR-140-5p in overall survival, chemoresistance prognosis and treatment.
Effects of landscape pattern changes on ecosystem services: a case study of Ruoergai Plateau
This study investigates the impact of landscape patterns on ecosystem services in the Ruoergai Plateau from 1990 to 2020. Ecosystem services play a crucial role in maintaining the balance of natural ecosystems and facilitating socio-economic development. Using the InVEST model, it quantifies and assesses carbon storage, soil conservation, water yield, and habitat quality. Correlation analysis is employed to explore the interrelationships and constraints among different ecosystem services, while stepwise regression analysis and bivariate spatial autocorrelation are utilized to investigate the impact mechanisms of landscape patterns on ecosystem services. Results indicate that the Ruoergai Plateau has experienced changes and transitions in land use, with grasslands being the primary type showing a decreasing trend. Landscape patterns have significantly altered, with a mitigation of fragmentation observed. Overall, ecosystem services show a declining trend initially followed by an increase. Carbon stock showed a decreasing trend from 1990 to 2010, with a significant increase from 2010 to 2020 and an increase of 0.41 × 10 8 t. The average carbon density and stock in the study area in 2020 reached 78.48 t.hm − 2 and 3.64 × 10 8 t, which were mainly concentrated in the wetland and forested land, distributed in the eastern and southwestern parts of the study area. There exist varied trade-offs and coordination among ecosystem services across different regions and temporal scales, while demonstrating a certain correlation with landscape indices. These findings enhance our understanding of how landscape pattern dynamics shape ecosystem service functions, providing valuable insights for regional ecological management and sustainable development.
Naringenin is a Potential Anabolic Treatment for Bone Loss by Modulating Osteogenesis, Osteoclastogenesis, and Macrophage Polarization
Bone undergoes constant remodeling of formation by osteoblasts and resorption by osteoclasts. In particular, macrophages have been reported to play an essential role in the regulation of bone homeostasis and regeneration. Naringenin, the predominant flavanone in citrus fruits, is reported to exert anti-inflammatory, anti-osteoclastic, and osteogenic effects. However, whether naringenin could modulate the crosstalk between macrophages and osteoblasts/osteoclasts remains to be investigated. In this study, we confirmed that naringenin enhanced osteogenesis and inhibited osteoclastogenesis directly. Naringenin promoted M2 transition and the secretion of osteogenic cytokines including IL-4, IL-10, BMP2, and TGF-β, while suppressing LPS-induced M1 polarization and the production of proinflammatory factors such as TNF-α and IL-1β. In addition, the coculture of primary bone mesenchymal stem cells (BMSCs)/bone marrow monocytes (BMMs) with macrophages showed that the naringenin-treated medium significantly enhanced osteogenic differentiation and impeded osteoclastic differentiation in both inflammatory and non-inflammatory environment. Moreover, in vivo experiments demonstrated that naringenin remarkably reversed LPS-induced bone loss and assisted the healing of calvarial defect. Taken together, naringenin serves as a potential anabolic treatment for pathological bone loss.
Asymmetric expression of H19 and ADIPOQ in concave/convex paravertebral muscles is associated with severe adolescent idiopathic scoliosis
Background Adolescent idiopathic scoliosis (AIS) is the most common paediatric spinal deformity. The etiology and pathology of AIS remain unexplained, and have been reported to involve a combination of genetic and epigenetic factors. Since paravertebral muscle imbalance plays an important role in the onset and progression of scoliosis, we aimed to investigate transcriptomic differences by RNA-seq and identify significantly differentially expressed transcripts in two sides of paravertebral muscle in AIS. Methods RNA-seq was performed on 5 pairs of paravertebral muscle from 5 AIS patients. Significantly differentially expressed transcripts were validated by quantitative reverse polymerase chain reaction. Gene expression difference was correlated to clinical characteristics. Results We demonstrated that ADIPOQ mRNA and H19 is significantly differentially expressed between two sides of paravertebral muscle, relatively specific in the context of AIS. Relatively low H19 and high ADIPOQ mRNA expression levels in concave-sided muscle are associated with larger spinal curve and earlier age at initiation. We identified miR-675-5p encoded by H19 as a mechanistic regulator of ADIPOQ expression in AIS. We demonstrated that significantly reduced CCCTC-binding factor (CCTF) occupancy in the imprinting control region (ICR) of the H19 gene in the concave-sided muscle contributes to down-regulated H19 expression. Conclusions RNA-seq revealed transcriptomic differences between two sides of paravertebral muscle in AIS patients. Our findings imply that transcriptomic differences caused by epigenetic factors in affected individuals may account for the structural and functional imbalance of paravertebral muscle, which can expand our etiologic understanding of this disease.
Vertebral artery injury following combination Jefferson fracture of C1 and Type II odontoid fracture: A case report
Key Clinical Message Traumatic posterior atlantoaxial dislocation combined with Jefferson fracture and odontoid process fracture with vertebral artery injury is rare. The management of such injury raises controversial issues and is still open to debate. A 74‐year‐old Chinese male presented with sustained neck pain and stiffness after falling from height. The patient was neurologically intact. Preoperative radiographs demonstrated a Jefferson burst fracture with a posterior dislocation of the atlantoaxial joints and odontoid process Anderson and D'alonzo type II fracture. A computed tomography angiography (CTA) showed an occluded left vertebral artery. Coil embolization in the proximal portion of the occluded vertebral artery was performed to prevent further cerebral infarction due to distal embolization of the thrombus. Then a second stage occipito‐cervical fusion was performed to reconstruct cervical spine stability. A systematic screening of blunt trauma vertebral artery injuries through CTA is required when dealing with upper cervical fracture. For cases with vertebral artery occlusion secondary to cervical spine injury, endovascular treatment preceding cervical spine surgery is a feasible and a safe treatment.
Modified C7 pedicle subtraction osteotomy for the correction of cervicothoracic kyphosis
Background Osteotomies in the cervical spine are technically challenging. The purpose of this study was to evaluate the feasibility of the modified pedicle subtraction osteotomy (PSO) technique at C7 to be used for the treatment of cervicothoracic kyphosis secondary to ankylosing spondylitis. Methods A total of 120 cervical spine computed tomography (CT) scans (of 82 male and 38 female patients) were evaluated. The scans were taken parallel to the middle sagittal plane and the sagittal plane intersecting the pedicles. Simulated osteotomy was performed by setting the apex of the wedge osteotomy at different points, and morphologic measurements were obtained. Seven patients with cervicothoracic kyphosis who underwent a modified PSO at C7 between May 2009 and June 2015 were retrospectively evaluated. The mean follow up was 32.9 months (range 21–54 months). Preoperative and postoperative chin-brow vertical angle (CBVA), sagittal vertical axis (SVA) and sagittal Cobb angle of the cervical region were reviewed. The outcomes were analyzed through various measures, which included the 36-Item Short Form Health Survey (SF-36) and a visual analog scale for neck pain. Results In this morphometric study, a modified PSO was performed on 87 patients (59 male and 28 female) with a reasonable ratio of 72.5%. In the case series, radiographic parameters and health-related quality-of-life measures were found to show significant postoperative improvement in all patients. No major complications occurred, and no implant failures were noted until the latest follow up. Conclusions The modified PSO is a safe and valid alternative to the classic PSO, allowing for excellent correction of cervical kyphosis and improvement in health-related quality-of-life measures.
Pulmonary Recovery Following Corrective Surgery in Adult Patients With Severe Scoliosis: A Minimum of Five-Year Follow-Up
BackgroundHalo gravity traction (HGT) has been reported to be a safe and effective adjunctive method for the management of scoliosis. However, the direct effects of HGT on the lung recovery of adult patients with scoliosis remain obscure.ObjectiveTo investigate changes in lung volume and pulmonary function in adult patients with severe scoliosis who underwent posterior spinal fusion concomitant with preoperative halo gravity traction.MethodsA total of 47 patients with a minimum 5-year follow-up who underwent posterior spinal instrumentation and fusion using preoperative halo–gravity traction were analyzed. Pulmonary function tests and three-dimensional CT were performed to evaluate changes in lung function and lung volume, respectively.ResultsThere was significant change in the Cobb angle of the major curve after halo gravity traction ( P < 0.0001). Significant improvement in both Cobb angle ( P < 0.0001) and thoracic kyphosis ( P = 0.034) after corrective surgery was observed. Pulmonary function did not change significantly during traction. However, a significant decline in absolute and percent-predicted pulmonary function values was noted following surgery. The average change in lung volume did not show statistical differences during traction. At 5-year postoperative follow-up, the mean values revealed a significant increase in total lung volume ( P < 0.0001) and concave lung volume ( P < 0.0001) with surgical correction, but no statistically significant change in lung volume on the convex side ( P = 0.57). Postoperative pulmonary complications occurred in nine cases with lower preoperative pulmonary function, indicating the importance of performing spirometry before corrective surgery.ConclusionsWe found that halo gravity traction prior to corrective surgery was less useful in improving pulmonary function in adult patients with severe scoliosis. However, these patients were expected to have increased lung volume after correction of the deformity.