Thymosin beta 10 loaded ZIF-8/sericin hydrogel promoting angiogenesis and osteogenesis for bone regeneration.

Angiogenesis is pivotal for osteogenesis during bone regeneration. A hydrogel that promotes both angiogenesis and osteogenesis is essential in bone tissue engineering. However, creating scaffolds with the ideal balance of biodegradability, osteogenic, and angiogenic properties poses a challenge. Thymosin beta 10 (TMSB10), known for its dual role in angiogenesis and osteogenesis differentiation, faces limitations due to protein activity preservation. To tackle this issue, ZIF-8 was engineered as a carrier for TMSB10 (TMSB10@ZIF-8), and subsequently integrated into the self-assembled sericin hydrogel. The efficacy of the composite hydrogel in bone repair was assessed using a rat cranial defect model. Characterization of the nanocomposites confirmed the successful synthesis of TMSB10@ZIF-8, with a TMSB10 encapsulation efficiency of 88.21 %. The sustained release of TMSB10 from TMSB10@ZIF-8 has significantly enhanced tube formation in human umbilical vein endothelial cells (HUVECs) in vitro and promoted angiogenesis in the chicken chorioallantoic membrane (CAM) model in vivo. It has markedly improved the osteogenic differentiation ability of MC 3 T3-E1 cells in vitro. 8 weeks post-implantation, the TMSB10@ZIF-8/ Sericin hydrogel group exhibited significant bone healing (86.77 ± 8.91 %), outperforming controls. Thus, the TMSB10@ZIF-8/Sericin hydrogel, leveraging ZIF-8 for TMSB10 delivery, emerges as a promising bone regeneration scaffold with substantial clinical application potential.

The critical role of toll-like receptor 4 in bone remodeling of osteoporosis: from inflammation recognition to immunity.

Osteoporosis is a common chronic metabolic bone disorder. Recently, increasing numbers of studies have demonstrated that Toll-like receptor 4 (TLR4, a receptor located on the surface of osteoclasts and osteoblasts) plays a pivotal role in the development of osteoporosis. Herein, we performed a comprehensive review to summarize the findings from the relevant studies within this topic. Clinical data showed that TLR4 polymorphisms and aberrant TLR4 expression have been associated with the clinical significance of osteoporosis. Mechanistically, dysregulation of osteoblasts and osteoclasts induced by abnormal expression of TLR4 is the main molecular mechanism underlying the pathological processes of osteoporosis, which may be associated with the interactions between TLR4 and NF-κB pathway, proinflammatory effects, ncRNAs, and RUNX2. In vivo and in vitro studies demonstrate that many promising substances or agents (i.e., methionine, dioscin, miR-1906 mimic, artesunate, AEG-1 deletion, patchouli alcohol, and Bacteroides vulgatus) have been able to improve bone metabolism (i.e., inhibits bone resorption and promotes bone formation), which may partially attribute to the inhibition of TLR4 expression. The present review highlights the important role of TLR4 in the clinical significance and the pathogenesis of osteoporosis from the aspects of inflammation and immunity. Future therapeutic strategies targeting TLR4 may provide a new insight for osteoporosis treatment.

Degradation Kinetic Studies of BSA@ZIF-8 Nanoparticles with Various Zinc Precursors, Metal-to-Ligand Ratios, and pH Conditions.

Nanosized zeolitic imidazolate framework particles (ZIF-8 nanoparticles [NPs]) have strong potential as effective carriers for both in vivo and in vitro protein drug delivery. Synthesis of ZIF-8 and stability of protein encapsulation within ZIF-8 are affected by several factors, notably the metal ion source and molar ratio. To systematically investigate these factors, we investigated such effects using BSA as a model test protein to synthesize BSA@ZIF-8 NPs at various metal-to-ligand (M:L) ratios. SEM, FTIR, XRD, and DLS were applied to characterize the morphology and structure of BSA@ZIF-8 NPs and their effects on protein loading capacity. Degradation kinetics and protein release behavior of BSA@ZIF-8 NPs were evaluated at pH 5.0 (to simulate the tumor environment) and pH 7.4 (to mimic the blood environment). Our objective was to define optimal combinations of the high protein loading rate and rapid release under varying pH conditions, and we found that (i) the yield of BSA@ZIF-8 NPs decreased as the M:L ratio increased, but the protein content increased. This highlights the need to strike a balance between cost-effectiveness and practicality when selecting ZIF-8 NPs with different molar ratios for protein-based drug formulation. (ii) BSA@ZIF-8 NPs exhibited cruciate flower-like shapes when synthesized using Zn(NO3)2 as the zinc precursor at M:L ratios of 1:16 or 1:20. In all other cases, the NPs displayed a regular rhombic dodecahedral structure. Notably, the release behavior of the NPs did not differ significantly between these morphologies. (iii) When Zn(OAc)2 was used as the zinc precursor, the synthesized ZIF-8 NPs exhibited a smaller size compared to the Zn(NO3)2-derived ZIF-8 NPs. (iv) The release rate and amount of BSA protein were higher at pH 5.0 compared to pH 7.4. (v) Among the different formulations, BSA@ZIF-8 with an M:L ratio of 1:16 at pH 5.0 was observed to have a shorter time to reach a plateau (0.5 h) and higher protein release, making it suitable for locally rapid administration in a tumor environment. BSA@ZIF-8 prepared from Zn(OAc)2 at an M:L ratio of 1:140 showed the slower release of BSA protein over a 24-h period, indicating its suitability for sustained release delivery. In conclusion, our findings provide a useful basis for the practical application of ZIF-8 NPs in protein-based drug delivery systems.

Circ_0001825 promotes osteogenic differentiation in human-derived mesenchymal stem cells via miR-1270/SMAD5 axis.

BACKGROUND: The implication of deregulated circular RNAs in osteoporosis (OP) has gradually been proposed. Herein, we aimed to study the function and mechanism of circ_0001825 in OP using osteogenic-induced human-derived mesenchymal stem cells (hMSCs). METHODS: The content of genes and proteins was tested by quantitative real-time polymerase chain reaction and Western blotting. The osteogenic differentiation in hMSCs were evaluated by ALP activity and Alizarin Red staining, as well as the detection of osteogenesis-related markers. Cell viability and apoptosis were measured by CCK-8 assay and flow cytometry. The binding between miR-1270 and circ_0001825 or SMAD5 (SMAD Family Member 5) was confirmed by using dual-luciferase reporter assay and pull-down assay. RESULTS: Circ_0001825 was lowly expressed in OP patients and osteogenic induced hMSCs. Knockdown of circ_0001825 suppressed hMSC viability and osteogenic differentiation, while circ_0001825 overexpression showed the exact opposite effects. Mechanistically, circ_0001825/miR-1270/SMAD5 formed a feedback loop. MiR-1270 was increased and SMAD5 was decreased in OP patients and osteogenic induced hMSCs. MiR-1270 up-regulation suppressed hMSC viability and osteogenic differentiation, which was reversed by SMAD5 overexpression. Moreover, miR-1270 deficiency abolished the effects of circ_0001825 knockdown on hMSCs. CONCLUSION: Circ_0001825 promoted hMSC viability and osteogenic differentiation via miR-1270/SMAD5 axis, suggesting the potential involvement of circ_0001825 in osteoporosis.

Effects of basic medical insurance integration on subjective wellbeing of residents in China: empirical evidence from a quasi-experiment.

Introduction: Enhancing the wellbeing of residents through universal health coverage (UHC) is a long-term policy goal for China. In 2016, China integrated the New Rural Cooperative Medical Scheme (NRCMS) and the Urban Resident Basic Medical Insurance (URBMI) into the Urban and Rural Resident Basic Medical Insurance (URRBMI) to address the problem of fragmentation. Objective: The objective of this study was to investigate whether the integration of basic medical insurance had an impact on the subjective wellbeing of Chinese residents. Methods: Using the China Household Finance Survey data of 2015 and 2019, we empirically estimated the influence of the integration of basic medical insurance on Chinese residents through the difference-in-difference method based on propensity score matching (PSM-DID). Results: Our findings indicate that the integration of basic medical insurance improved the subjective wellbeing of the insured population. Additionally, through heterogeneity testing, we validated that the integration increased the subjective wellbeing of residents from less developed regions in West China and rural areas, as well as those with older adult dependents. However, the subjective wellbeing of low-income groups, who were expected to benefit more from the URRBMI, did not improve significantly, at least in the short term. Conclusion: According to our research, the integration of basic medical insurance in China supports the country's objective of achieving equality and providing universal benefits for its residents. The introduction of the URRBMI has had a positive impact on the subjective wellbeing of insured individuals. This is particularly beneficial for disadvantaged groups in less developed regions, as well as for residents with older adult dependents. However, the subjective wellbeing of the middle-income group has improved significantly, whereas that of the low-income group, despite being the intended beneficiaries of the integration, did not show significant improvement. Recommendations: From a funding perspective, we recommend establishing a dynamic adjustment funding system that links residents' medical insurance funding standards with their disposable income. Regarding the utilization of the URRBMI, the benefit packages should be expanded, particularly by covering more outpatient services through risk pooling. We call for further research with additional data and continued efforts on improving wellbeing of residents, particularly for disadvantaged populations.

Lupeol-loaded chitosan-Ag+ nanoparticle/sericin hydrogel accelerates wound healing and effectively inhibits bacterial infection.

Lupeol, a pentacyclic triterpene, has demonstrated significant wound healing properties; however, its low water solubility has limited its clinical applicability. To overcome this limitation, we utilized Ag+-modified chitosan (CS-Ag) nanoparticles to deliver lupeol, resulting in the formation of CS-Ag-L-NPs. These nanoparticles were then encapsulated within a temperature-sensitive, self-assembled sericin hydrogel. Various analytical methods, including SEM, FTIR, XRD, HPLC, TGA assay, hemolysis and antibacterial activity tests, were employed to characterize the nanoparticles. Additionally, an infectious wound model was used to evaluate the therapeutic and antibacterial efficacy of the CS-Ag-L-NPs modified sericin hydrogel. Our results showed that the encapsulation efficiency of lupeol in CS-Ag-L-NPs reached 62.1 %, with good antibacterial activity against both gram-positive and gram-negative bacteria and a low hemolysis ratio (<5 %). The CS-Ag-L-NPs sericin gel exhibited multiple beneficial effects, including inhibiting bacterial proliferation in wound beds, promoting wound healing via accelerated re-epithelialization, reducing inflammation, and enhancing collagen fiber deposition. We conclude that the CS-Ag-L-NPs loaded sericin hydrogel has tremendous potential for development as a multifunctional therapeutic platform capable of accelerating wound healing and effectively suppressing bacterial infections in clinical settings.

The best position of bone grafts in the medial open-wedge high tibial osteotomy: A finite element analysis.

BACKGROUND AND OBJECTIVE: The application of wedge-shaped bone grafts can increase the biomechanical stability of knee during the medial open-wedge high tibial osteotomy (MOWHTO) by reducing the von Mises stress of the medial plate and lateral cortical hinge area. However, the optimal position of bone grafts it remains unclear, so we aimed to determine search for the optimal position of the bone grafts in MOWHTO by using finite element analysis. METHODS: In the finite element analysis, MOWHTO models were established with three different osteotomy distraction heights and assembled into four groups according to different conditions, including the no bone grafts (NBG) group, the anterior bone grafts (ABG) group, the middle bone grafts (MBG) group, and the posterior bone grafts (PBG) group. Based on previous studies, 600 N and 1800 N loads were applied to the knee joint to simulate the static forces during a double and single leg stance to measure the von Mises stress of the medial implant area and lateral hinge area, the maximum displacement of different models, the relative displacement of the osteotomy area and the stress distribution in the bone grafts. RESULTS: Compared to the NBG and ABG groups, the stress of the lateral cortical hinge area and the medial implate area was significantly lower in the PBG group. For example, under the 600N force load, when the height of the osteotomy area was 10 mm, 15 mm, and 20 mm, the maximum von Mises stress of the medial implate area and lateral cortical hinge area in the NBG group were 140, 141, 172, and 53, 57, 60 MPa, respectively. Compared with the NBG group, the maximum von Mises stress of the medial implate area and lateral cortical hinge area in the PBG group were reduced by 45%, 56%, 63% and 14%, 39%, 68% at distraction height of 10 mm, 15 mm, and 20 mm, respectively. The bone grafts in the posterior parts provide the best stability,with the stress of the middle and posterior bone grafts are mainly concentrated in the edge. CONCLUSIONS: The posterior part of the osteotomy area is the best position for bone graft placement since it provides optimal stability and reduces von Mises stress in the medial plate and lateral cortex hinge area, with the stress of the posterior bone grafts mainly concentrated in the edge. These findings guide bone graft placement sites in clinical surgery and are a basis for future research on bone graft materials and structures in MOWHTO.

Current knowledge of leptin in wound healing: A collaborative review.

Efficacious wound healing is still a major concern for global healthcare due to the unsatisfactory outcomes under the current treatments. Leptin, an adipocyte-derived hormone, mainly acts in the hypothalamus and plays crucial roles in various biological processes. Recently, an increasing number of researches have shown that leptin played an important role in the wound healing process. In this review, we presented a first attempt to capture the current knowledge on the association between leptin and wound healing. After a comprehensive review, the molecular mechanisms underlying leptin in wound healing were speculated to be correlated to the regulation of inflammation of the macrophage and lymphocytes, angiogenesis, re-epithelialization, proliferation, and differentiation of fibroblasts. The affected genes and the signal pathways were multiple. For example, leptin was reported to ameliorate wound healing by its anti-inflammatory action, which might be correlated to the activation STAT1 and STAT3 via p38 MAPK or JAK2. However, the understanding of the specific role in each process (e.g., inflammatory, proliferative, and maturation phase) of wound repair is not entirely clear, and further studies are still warranted in both macrostructural and microscale factors. Therefore, identifying and validating the biological mechanisms of leptin in wound healing is of great significance to develop potential therapeutic targets for the treatment of wound healing in clinical practice.

Roles of ARID1A variations in colorectal cancer: a collaborative review.

Colorectal cancer (CRC), a common malignancy, is one of the leading cause of cancer death in adults. AT-rich interaction domain 1A (ARID1A), a critical portion of the SWItch/sucrose non-fermentation (SWI/SNF) chromatin remodeling complexes, shows one of the most frequent mutant genes across different human cancer types. Deleterious variations of ARID1A has been recognized to be correlated the tumorigenesis and the poor prognosis of CRC. Here, we summarize recent advances in the clinical implications and molecular pathogenesis of ARID1A variations in CRC. According to independent data of 23 included studies, ARID1A is mutated in 3.6-66.7%. Consistently, all of the 23 relevant studies report that ARID1A functions as a specific tumor suppressor in CRC. Clinically, ARID1A variation status serves as a biomarker for survival prognosis and various therapies for CRC. Mechanistically, the pathophysiologic impacts of ARID1A variations on CRC may be associated with the co-occurrence variations of other genes (i.e., TP53, KRAS, APC, FBXW7, and PIK3CA) and the regulation of several signaling pathways being affected (i.e., WNT signaling, Akt signaling, and MEK/ERK pathway), leading to cell cycle arrest, chromatin remodeling, chromosome organization, and DNA hypermethylation of the cancer cells. The present review highlights ARID1A serving as a potent tumor suppressor and an important prognostic factor in CRC. ARID1A variations hint towards a promising tool for diagnostic tumor profiling and individualized therapeutic targets for CRC in the future.

Role and Mechanism of circ_0058063/miR-635 Axis in the Malignant Phenotype of Multiple Myeloma RPMI8226 Cells.

OBJECTIVE: This study aims to explore circ_0058063 effect on multiple myeloma cells malignant phenotype and its feasible mechanism. METHODS: We selected 47 cases of multiple myeloma tissues and 47 cases of normal bone marrow tissues and then used RT-qPCR method to test circ_0058063 and miR-635 expression in the tissues. Myeloma cells RPMI8226 were transfected with si-circ_0058063, miR-635 mimic, and si-circ_0058063 + anti-miR-635, respectively. Then, we adopt CCK-8 method, flow cytometry method, and Transwell and western blot methods to detect the influences of knockdown of circ_0058063 or miR-635 overexpression on RPMI8226 cell proliferation, apoptosis, migration, and invasion and also Ki-67, Bax, Bcl-2, MMP-2, and MMP-9 protein expression. The dual luciferase reporter gene assay experiment proved that it has regulatory relationship between circ_0058063 and miR-635. RESULTS: circ_0058063 expression of multiple myeloma was higher than that in normal bone marrow tissue (P < 0.05), while miR-635 expression was lower than that in normal bone marrow tissue (P < 0.05). Knockdown of circ_0058063 or overexpression of miR-635 could reduce proliferation capacity, migration, invasion cell quantities, and Ki-67, MMP-2, MMP-9, and Bcl-2 protein expression (P < 0.05), while increasing apoptosis rate together with Bax protein expression (P < 0.05). circ_0058063 targets to negatively regulate miR-635, while knocking down miR-635 reverses the influences of knocking down circ_0058063 on RPMI8226 proliferation, apoptosis, migration, and invasion. CONCLUSION: circ_0058063 expression increased in multiple myeloma tissues. Knocking down its expression may inhibit myeloma proliferation, migration, and invasion by targeting and upregulating miR-635 and also promote cell apoptosis. As for multiple myeloma treatment, circ_0058063/miR-635 may provide new molecular targets.

Is there an association between peptic ulcer disease and osteoporosis: a systematic review and cumulative analysis.

BACKGROUND: Mounting studies have emerged indicating that patients with peptic ulcer disease (PUD) are at a high risk of developing osteoporosis, but the evidence has not been previously synthesized. The present study aims to examine whether patients with PUD have a significantly higher prevalence of osteoporosis than the healthy normal subjects. METHODS: Four electronic databases were systematically searched for eligible studies up to February 2020. The association between PUD and osteoporosis was evaluated by calculating the relative risk (RR) with a 95% confidence interval (CI). RESULTS: Six observational studies were finally included, enrolling a total of 216 122 individuals. Synthetic results from the six included studies providing the number of cases for both sexes demonstrated that PUD was significantly associated with an increased risk of osteoporosis (95% CI, 1.37-1.89; P < 0.001). In line with this finding, the combined effect from the three studies independently reporting the male subjects also yielded to a positive relationship between PUD and osteoporosis (RR = 2.08; 95% CI,1.10-3.93; P = 0.023). However, when restricted to female participants, pooled results indicated that women patients with PUD would not suffer significantly more risk of osteoporosis than the general women population (RR = 1.36; 95% CI, 0.84-2.21, P = 0.212). CONCLUSIONS: This is the first study for quantifying the positive association between PUD and the risk of osteoporosis by conducting a meta-analysis. In clinical practice, assessment of the bone mineral density and antiosteoporosis treatments are recommended for those potential patients with PUD.

PPAR-γ Is Critical for HDAC3-Mediated Control of Oligodendrocyte Progenitor Cell Proliferation and Differentiation after Focal Demyelination.

Disruption of remyelination contributes to neurodegeneration and cognitive impairment in chronically disabled patients. Valproic acid (VPA) inhibits histone deacetylase (HDAC) function and probably promotes oligodendrocyte progenitor cell (OPC) proliferation and differentiation; however, the relevant molecular mechanisms remain unknown. Here, focal demyelinating lesions (FDLs) were generated in mice by two-point stereotactic injection of lysophosphatidylcholine (LPC) into the corpus callosum. Cognitive functions, sensorimotor abilities and histopathological changes were assessed for up to 28 days post-injury with or without VPA treatment. Primary OPCs were harvested and used to study the effect of VPA on OPC differentiation under inflammatory conditions. VPA dose-dependently attenuated learning and memory deficits and robustly protected white matter after FDL induction, as demonstrated by reductions in SMI-32 and increases in myelin basic protein staining. VPA also promoted OPC proliferation and differentiation and increased subsequent remyelination efficiency by day 28 post-FDL induction. VPA treatment did not affect HDAC1, HDAC2 or HDAC8 expression but reduced HDAC3 protein levels. In vitro, VPA improved the survival of mouse OPCs and promoted their differentiation into oligodendrocytes following lipopolysaccharide (LPS) stimulation. LPS caused OPCs to overexpress HDAC3, which translocated from the cytoplasm into the nucleus, where it directly interacted with the nuclear transcription factor PPAR-γ and negatively regulated PPAR-γ expression. VPA decreased the expression of HDAC3 and promoted remyelination and functional neurological recovery after FDL. These findings may support the use of strategies modulating HDAC3-mediated regulation of protein acetylation for the treatment of demyelination-related cognitive dysfunction.

Hypoxic preconditioning enhances the differentiation of bone marrow stromal cells into mature oligodendrocytes via the mTOR/HIF-1α/VEGF pathway in traumatic brain injury.

OBJECTIVE: Traumatic brain injury (TBI) results not only in gray matter damage, but also in severe white matter injury (WMI). Previous findings support hypoxic preconditioning (HP) could augment the efficacy of bone marrow stromal cell (BMSC) transplantation in a TBI mouse model. However, whether HP-treated BMSCs (H-BMSCs) could overcome remyelination failure after WMI is unclear, and the molecular mechanisms remain to be explored. Here, we focused on the therapeutic benefits of H-BMSC transplantation for treating WMI, as well as its underlying mechanisms. METHODS: In vitro, BMSCs were incubated at passage 4 in the hypoxic preconditioning (1.0% oxygen) for 8 hr. In vivo, a TBI mouse model was established, and DMEM cell culture medium (control), normal cultured BMSCs (N-BMSCs), or H-BMSCs were transplanted to mice 24 hr afterward. Neurobehavioral function, histopathological changes, and oligodendrogenesis were assessed for up to 35 days post-TBI. RESULTS: Compared with the control group, improvement of cognitive functions and smaller lesion volumes was observed in the two BMSC-transplanted groups, especially the H-BMSC group. H-BMSC transplantation resulted in a greater number of neural/glial antigen 2 (NG2)-positive and adenomatous polyposis coli (APC)-positive cells than N-BMSC transplantation in both the corpus callosum and the striatum. In addition, we observed that the expression levels of hypoxia-inducible factor-1a (HIF-1α), phosphorylated mechanistic target of rapamycin (p-mTOR), and vascular endothelial growth factor (VEGF) were all increased in H-BMSC-transplanted mice. Furthermore, the mTOR pathway inhibitor rapamycin attenuated the impact of HP both in vivo and in vitro. CONCLUSION: The results provided mechanistic evidences suggesting that HP-treated BMSCs promoted remyelination partly by modulating the pro-survival mTOR/HIF-1α/VEGF signaling pathway.

Retraction Note to: The Association Between Modic Changes of Lumbar Endplates and Spontaneous Absorption of Herniated Intervertebral Discs.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Regulation of AKT phosphorylation by GSK3ß and PTEN to control chemoresistance in breast cancer.

BACKGROUND: Phosphorylated AKT is highly expressed or overexpressed in chemoresistant tumor samples. However, the precise molecular mechanism involved in AKT phosphorylation-related chemoresistance in breast cancer is still elusive. The present research was designed to estimate the effect of AKT phosphorylation on cell viability and chemoresistance in breast cancer. METHODS: We utilized MCF-7 and MDA-MB468 human breast cancer cell lines and developed multidrug-resistant MCF-7/MDR and cisplatin-resistant MDA-MB-468 cells. Immunofluorescence analysis and Western blotting were employed to test the level of glycogen synthase kinase 3 beta (GSK3ß), phosphorylated phosphatase and tension homologue (p-PTEN) and phosphorylated AKT (p-AKT) in MCF-7/MDR and MDA-MB468 cells. Xenograft assays in nude mice were performed with MCF-7/MDR cells to verify chemoresistance and the signaling pathway upstream of phosphatidylinositide 3-kinase (PI3K)/AKT. RESULTS: An increase in GSK3ß, p-PTEN and p-AKT expression was strongly induced in MCF-7/MDR and cisplatin-resistant MDA-MB-468 cells, and augmented GSK3ß phosphorylation and PTEN inactivation enhanced AKT signaling. The elevation in GSK3ß, p-PTEN and p-AKT was associated with cell viability based on a CCK-8 assay. The results of in vivo and in vitro assays indicated that GSK3ß knockdown with lentiviral shRNA (shRNA-GSK3ß) promoted apoptosis and suppressed the migration of cisplatin-resistant MCF-7/MDR cells, while these effects were reversed by activating p-AKT with the PTEN inhibitor bpV(pic). CONCLUSIONS: AKT phosphorylation mediated by GSK3ß and PTEN were correlated with cell viability, migration and apoptosis, which may promote chemoresistance in breast cancer. Furthermore, GSK3ß can regulate cell viability through the PTEN/PI3K/AKT signaling pathway and induce chemoresistance, serving as a valuable molecular strategy for breast cancer therapy.

Neuroprotective effect of l-serine against white matter demyelination by harnessing and modulating inflammation in mice.

Demyelination in white matter is the end product of numerous pathological processes. This study was designed to evaluate the neuroprotective effect of l-serine and the underlying mechanisms against the demyelinating injury of white matter. A model of focal demyelinating lesions (FDL) was established using the two-point stereotactic injection of 0.25% lysophosphatidylcholine (LPC, 10 µg per point) into the corpus callosum of mice. Mice were then intraperitoneally injected with one of three doses of l-serine (114, 342, or 1026 mg/kg) 2 h after FDL, and then twice daily for the next five days. Behavior tests and histological analysis were assessed for up to twenty-eight days post-FDL induction. Electron microscopy was used for ultrastructural investigation. In vitro, we applied primary co-cultures of microglia and oligodendrocytes for oxygen glucose deprivation (OGD). After establishing FDL, l-serine treatment: 1) improved spatial learning, memory and cognitive ability in mice, and relieved anxiety for 4 weeks post-FDL induction; 2) reduced abnormally dephosphorylated neurofilament proteins, increased myelin basic protein, and preserved anatomic myelinated axons; 3) inhibited microglia activation and reduced the release of inflammatory factors; 4) promoted recruitment and proliferation of oligodendrocyte progenitor cells, and the efficiency of subsequent remyelination on day twenty-eight post-FDL induction. In vitro experiments, showed that l-serine not only directly protected against oligodendrocytes from OGD damage, but also provided an indirect protective effect by regulating microglia. In our study, l-serine offered long-lasting behavioral and oligodendrocyte protection and promoted remyelination. Therefore, l-serine may be an effective clinical treatment aganist white matter injury.

A stable and easily reproducible model of focal white matter demyelination.

BACKGROUND: Demyelination is the end product of numerous pathological processes, and also is one of the main causes of neurological disability in Multiple sclerosis (MS). Research into the pathogenesis of MS is hampered by the conventional rodent models' inability to produce stable demyelination. NEW METHOD: Focal demyelinating lesions were stereotactically targeted to the corpus callosum with a two-point injection of lysophosphatidylcholine (LPC-2) in mice. Three groups were analyzed (n = 8, each) and water maze, sensorimotor test, and compound action potential were included in functional tests. Electron microscopy was used for morphological analyses while western blot and immunohistochemistry were included for molecular detection. RESULTS: Ten days after the LPC-2 injection, the expression of myelin basic protein (MBP) was reduced, while non-phosphorylated neurofilament (SMI-32) was increased. The amplitude of the N1 segment decreased and less well-defined myelin sheaths was found. Behavioral tests showed increased latency to escape and reduced time spent in target quadrant. Four weeks later, MBP expression still reduced, SMI-32 expression was increased, both spatial learning (D24-D27) and spatial memory (D28) were still significantly impaired in LPC-2 injection mice. COMPARISON WITH EXISTING METHOD(S): Compared with the classic single-point LPC-injection model, our studies showed that the two-point LPC-injection not only could induce demyelination in a short-term manner, but also could cause demyelination in a long-term manner with little remyelination in the mouse corpus callosum. CONCLUSIONS: We established a simple, reliable, and inexpensive model of demyelination in the corpus callosum in mice, with functional and morphological reproducibility, and good validity.

Mangiferin inhibits apoptosis and oxidative stress via BMP2/Smad-1 signaling in dexamethasone-induced MC3T3-E1 cells.

Mangiferin is a xanthone glucoside, which possesses antioxidant, antiviral, antitumor and anti-inflammatory functions, and is associated with gene regulation. However, it remains unknown whether mangiferin protects osteoblasts, such as the MC3T3-E1 cell line, against glucocorticoid-induced damage. In the present study, MC3T3-E1 cells were treated with dexamethasone (Dex), which is a well-known synthetic glucocorticoid, in order to establish a glucocorticoid-induced cell injury model. After Dex and/or mangiferin treatment, cell viability, apoptosis and reactive oxygen species (ROS) production was measured by Cell Counting kit-8 (CCK-8) and flow cytometry, respectively, and the concentration of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and macrophage colony-stimulating factor (M-CSF) was measured by ELISA. The expression of bone morphogenetic protein 2 (BMP2), phosphorylated­SMAD family member 1 (p-Smad-1), t-Smad-1, osterix (OSX), osteocalcin (OCN), osteoprotegerin (OPG), receptor activator of nuclear factor-κB (RANK), RANK ligand (RANKL), B­cell lymphoma 2 (Bcl-2) and Bcl­2­associated X protein (Bax) was measured by real-time PCR and/or western blot analysis. The results indicated that pretreatment of MC3T3-E1 cells with mangiferin for 3 h prior to exposure to Dex for 48 h significantly attenuated Dex-induced injury and inflammation, as demonstrated by increased cell viability, and decreases in apoptosis, ROS generation, and the secretion of TNF-α, IL-6 and M-CSF. In addition, pretreatment with mangiferin markedly reduced Dex-induced BMP2 and p­Smad-1 downregulation, and corrected the expression of differentiation­ and apoptosis­associated markers, including alkaline phosphatase, OSX, OCN, OPG, RANK, RANKL, Bcl-2 and Bax, which were altered by Dex treatment. Similar to the protective effects of mangiferin, overexpression of BMP2 suppressed not only Dex-induced cytotoxicity, but also ROS generation, and the secretion of TNF-α, IL-6 and M-CSF. In conclusion, the results of the present study are the first, to the best of our knowledge, to demonstrate that mangiferin protects MC3T3-E1 cells against Dex-induced apoptosis and oxidative stress by activating the BMP2/Smad-1 signaling pathway.

The Association Between Modic Changes of Lumbar Endplates and Spontaneous Absorption of Herniated Intervertebral Discs.

Herniated disc (HD) is one of the most common causes of lower back pain. Treatment for HD includes conservative therapy and surgical intervention. Following conservative treatment, spontaneous absorption of HD occurs in some patients. To assess whether modic changes are associated with spontaneous absorption of HD, 85 patients with or without modic changes were followed up after 6 months of conservative treatment. As result, we found modic changes of lumbar endplates are associated with poor absorption of HD after conservative treatment. In addition, patients with modic changes exhibit significantly increased cartilage content and decreased neovascularization and macrophage infiltration in HD tissues, all of which are known to impair spontaneous absorption of herniated tissues. At molecular level, modic changes are associated with decreased expression of matrix metalloproteinase-3 gene, which is a key matrix-degrading enzyme for tissue absorption. Our study established a strong association between modic changes of lumbar endplates and spontaneous absorption of lumbar HD, which provided a potential novel method for prediction of spontaneous absorption.

Meta-analysis of the association between COL9A2 genetic polymorphisms and lumbar disc disease susceptibility.

STUDY DESIGN: Meta-analysis to collect all the relevant studies to date to further investigate whether or not the COL9A2 gene rs12077871, rs12722877, and rs7533552 polymorphism are associated with susceptibility to lumbar disc disease (LDD). OBJECTIVE: The aim of this study was to assess the association between the COL9A2 gene rs12077871, rs12722877, and rs7533552 and LDD. SUMMARY OF BACKGROUND DATA: LDD is a common musculoskeletal disease with strong genetic determinants. COL9A2 encodes the α2 (IX) chain of type IX collagen, which is the major collagen component of the hyaline cartilage. Growing numbers of studies have revealed the association between COL9A2 polymorphisms and susceptibility to LDD. However, those studies have yielded contradictory results. METHODS: Data were collected from the following electronic databases: PubMed, Web of Knowledge, and China National Knowledge Infrastructure, with the last report up to November 30, 2013. The odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of association under the allelic genetic model. We summarized the data on the association between COL9A2 rs12077871, rs12722877, and rs7533552 polymorphism and LDD in the overall studies. RESULTS: Nine case-control studies, including 1522 LDD cases and 1646 controls, were identified. The results indicated that the rs12077871, rs12722877, and rs7533552 variants in COL9A2 were not associated with LDD (rs12077871: C vs. T, OR = 0.541, 95% CI = 0.256-1.147, P = 0.109; rs12722877: C vs. G, OR = 1.199, 95% CI = 0.992-1.448, P = 0.06; rs7533552: A vs. G, OR = 0.993, 95% CI = 0.815-1.069, P = 0.320). Furthermore, the Egger test and the Begg funnel plot did not show any evidence of publication bias. CONCLUSION: Our results suggest that the COL9A2 rs12077871, rs12722877, and rs7533552 polymorphisms may not be associated with LDD. More studies based on larger sample sizes and homogeneous samples of patients with LDD are needed to confirm these findings. LEVEL OF EVIDENCE: 2.