Association between gut microbiota and spinal stenosis: a two-sample mendelian randomization study.

Introduction: Considerable evidence has unveiled a potential correlation between gut microbiota and spinal degenerative diseases. However, only limited studies have reported the direct association between gut microbiota and spinal stenosis. Hence, in this study, we aimed to clarify this relationship using a two-sample mendelian randomization (MR) approach. Materials and Methods: Data for two-sample MR studies was collected and summarized from genome-wide association studies (GWAS) of gut microbiota (MiBioGen, n = 13, 266) and spinal stenosis (FinnGen Biobank, 9, 169 cases and 164, 682 controls). The inverse variance-weighted meta-analysis (IVW), complemented with weighted median, MR-Egger, weighted mode, and simple mode, was used to elucidate the causality between gut microbiota and spinal stenosis. In addition, we employed mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) and the MR-Egger intercept test to assess horizontal multiplicity. Cochran's Q test to evaluate heterogeneity, and "leave-one-out" sensitivity analysis to determine the reliability of causality. Finally, an inverse MR analysis was performed to assess the reverse causality. Results: The IVW results indicated that two gut microbial taxa, the genus Eubacterium fissicatena group and the genus Oxalobacter, have a potential causal relationship with spinal stenosis. Moreover, eight potential associations between genetic liability of the gut microbiota and spinal stenosis were implied. No significant heterogeneity of instrumental variables or horizontal pleiotropy were detected. In addition, "leave-one-out" sensitivity analysis confirmed the reliability of causality. Finally, the reverse MR analysis revealed that no proof to substantiate the discernible causative relationship between spinal stenosis and gut microbiota. Conclusion: This analysis demonstrated a possible causal relationship between certain particular gut microbiota and the occurrence of spinal stenosis. Further studies focused on the mechanism of gut microbiota-mediated spinal stenosis can lay the groundwork for targeted prevention, monitoring, and treatment of spinal stenosis.

Scutellarein Ameliorated Chondrocyte Inflammation and Osteoarthritis in Rats.

OBJECTIVE: Osteoarthritis (OA) is a degenerative joint disorder characterized by the gradual degradation of joint cartilage and local inflammation. This study aimed to investigate the anti-OA effect of scutellarein (SCU), a single-unit flavonoid compound obtained from Scutellaria barbata D. Don, in rats. METHODS: The extracted rat chondrocytes were treated with SCU and IL-1ß. The chondrocytes were divided into control group, IL-1ß group, IL-1ß+SCU 50 µmol/L group, and IL-1ß+SCU 100 µmol/L group. Morphology of rat chondrocytes was observed by toluidine blue and safranin O staining. CCK-8 method was used to detect the cytotoxicity of SCU. ELISA, qRT-PCR, Western blotting, immunofluorescence, SAß-gal staining, flow cytometry, and bioinformatics analysis were applied to evaluate the effect of SCU on rat chondrocytes under IL-1ß intervention. Additionally, anterior cruciate ligament transection (ACL-T) was used to establish a rat OA model. Histological changes were detected by safranin O/fast green, hematoxylin-eosin (HE) staining, and immunohistochemistry. RESULTS: SCU protected cartilage and exhibited anti-inflammatory effects via multiple mechanisms. Specifically, it could enhance the synthesis of extracellular matrix in cartilage cells and inhibit its degradation. In addition, SCU partially inhibited the nuclear factor kappa-B/mitogen-activated protein kinase (NF-κB/MAPK) pathway, thereby reducing inflammatory cytokine production in the joint cartilage. Furthermore, SCU significantly reduced IL-1ß-induced apoptosis and senescence in rat chondrocytes, further highlighting its potential role in OA treatment. In vivo experiments revealed that SCU (at a dose of 50 mg/kg) administered for 2 months could significantly delay the progression of cartilage damage, which was reflected in a lower Osteoarthritis Research Society International (OARSI) score, and reduced expression of matrix metalloproteinase 13 (MMP13) in cartilage. CONCLUSION: SCU is effective in the therapeutic management of OA and could serve as a potential candidate for future clinical drug therapy for OA.

Elucidation of the mechanism of Zhenbao pills for the treatment of spinal cord injury by network pharmacology and molecular docking: A review.

To explore the mechanism of the Zhenbao pill (ZBP) in treating spinal cord injury (SCI). The TCMSP Database, HERB Database and literature search were used to screen the effective ingredients and targets of ZBP; SCI-related genes were searched in GeneCards, OMIM, PharmGkb, TTD and DrugBank databases; the potential targets of ZBP for treating SCI were predicted and Venn diagrams were drawn, and the "herb-ingredient-target" network was constructed by Cytoscape software. The PPI network was constructed by STRING software, and the core targets were screened by cytoNCA plug-in; GO enrichment and KEGG pathway analysis were performed on the predicted targets using the DAVID Platform, and visualized with the Microbiology Network Platform. The molecular docking between the key ingredients and the core target was carried out by AutoDockVina software. 391 active ingredients and 836 action targets were obtained from ZBP and there are 1557 SCI related genes in 5 disease databases. The top 5 active ingredients were Quercetin, Camptothecin, Kaempferol, Ethyl iso-allocholate, and Ethyl linoleate, and 5 core genes were SRC, CTNNB1, TP53, AKT1, and STAT3. GO enrichment analysis showed that the core targets were involved in 1206 biological processes, 120 cellular components and 160 molecular functions; KEGG enrichment analysis showed that the core targets involved 183 pathways, including PI3K-Akt signaling pathway and other signaling pathways. Molecular docking indicated that CTNNB1, SRC, TP53, AKT1 and STAT3 showed good binding ability with the active ingredients quercetin, kaempferol and ethyl isobutyric acid. ZBP improves SCI through multi-components, multi-targets and multi-pathways.

S100a9 inhibits Atg9a transcription and participates in suppression of autophagy in cardiomyocytes induced by ß1-adrenoceptor autoantibodies.

BACKGROUND: Cardiomyocyte death induced by autophagy inhibition is an important cause of cardiac dysfunction. In-depth exploration of its mechanism may help to improve cardiac dysfunction. In our previous study, we found that ß1-adrenergic receptor autoantibodies (ß1-AAs) induced a decrease in myocardial autophagy and caused cardiomyocyte death, thus resulting in cardiac dysfunction. Through tandem mass tag (TMT)-based quantitative proteomics, autophagy-related S100a9 protein was found to be significantly upregulated in the myocardial tissue of actively immunized mice. However, whether S100a9 affects the cardiac function in the presence of ß1-AAs through autophagy and the specific mechanism are currently unclear. METHODS: In this study, the active immunity method was used to establish a ß1-AA-induced mouse cardiac dysfunction model, and RT-PCR and western blot were used to detect changes in gene and protein expression in cardiomyocytes. We used siRNA to knockdown S100a9 in cardiomyocytes. An autophagy PCR array was performed to screen differentially expressed autophagy-related genes in cells transfected with S100a9 siRNA and negative control siRNA. Cytoplasmic nuclear separation, co-immunoprecipitation (Co-IP), and immunofluorescence were used to detect the binding of S100a9 and hypoxia inducible factor-1α (HIF-1α). Finally, AAV9-S100a9-RNAi was injected into mice via the tail vein to knockdown S100a9 in cardiomyocytes. Cardiac function was detected via ultrasonography. RESULTS: The results showed that ß1-AAs induced S100a9 expression. The PCR array indicated that Atg9a changed significantly in S100a9siRNA cells and that ß1-AAs increased the binding of S100a9 and HIF-1α in cytoplasm. Knockdown of S100a9 significantly improved autophagy levels and cardiac dysfunction. CONCLUSION: Our research showed that ß1-AAs increased S100a9 expression in cardiomyocytes and that S100a9 interacted with HIF-1α, which prevented HIF-1α from entering the nucleus normally, thus inhibiting the transcription of Atg9a. This resulted in autophagy inhibition and cardiac dysfunction.

Epac1 participates in ß1-adrenoreceptor autoantibody-mediated decreased autophagic flux in cardiomyocytes.

Decreased autophagic flux in cardiomyocytes is an important mechanism by which the ß1-adrenoreceptor (ß1-AR) autoantibody (ß1-AA) induces heart failure. A previous study found that ß1-AA imparts its biological effects via the ß1-AR/Gs/AC/cAMP/PKA canonical signaling pathway, but PKA inhibition does not completely reverse ß1-AA-induced reduction in autophagy in myocardial tissues, suggesting that other signaling molecules participate in this process. This study confirmed that Epac1 upregulation is indeed involved ß1-AA-induced decreased cardiomyocyte autophagy through CE3F4 pretreatment, Epac1 siRNA transfection, western blot and immunofluorescence methods. On this basis, we constructed ß1-AR and ß2-AR knockout mice, and used receptor knockout mice, ß1-AR selective blocker (atenolol), and the ß2-AR/Gi-biased agonist ICI 118551 to show that ß1-AA upregulated Epac1 expression through ß1-AR and ß2-AR to inhibit autophagy, and biased activation of ß2-AR/Gi signaling downregulated myocardial Epac1 expression to reverse ß1-AA-induced myocardial autophagy inhibition. This study aimed to test the hypothesis that Epac1 acts as another effector downstream of cAMP on ß1-AA-induced reduction in cardiomyocyte autophagy, and ß1-AA upregulates myocardial Epac1 expression through ß1-AR and ß2-AR, and biased activation of the ß2-AR/Gi signaling pathway can reverse ß1-AA-induced myocardial autophagy inhibition. This study provides new ideas and therapeutic targets for the prevention and treatment of cardiovascular diseases related to dysregulated autophagy.

miR-339-3p promotes AT1-AA-induced vascular inflammation by upregulating NFATc3 protein expression in vascular smooth muscle cells.

Vascular inflammation induced by angiotensin II-1 receptor autoantibody (AT1-AA) is involved in the occurrence and development of various cardiovascular diseases. miR-339-3p is closely related to the degree of vasodilation of aortic aneurysm and is also involved in the occurrence and development of acute pancreatitis. However, it is still unclear whether miR-339-3p influences AT1-AA-induced vascular inflammation. In this study, the role and mechanism of miR-339-3p in AT1-AA-induced vascular inflammation are studied. RT-PCR detection shows that the miR-339-3p levels in the thoracic aorta and serum exosomes of AT1-AA-positive rats are significantly increased. The miRwalk database predicts the mRNAs that miR-339-3p can bind to their 5'UTR. Subsequently, it is found that the number of genes contained in the T cell receptor pathway is high through KEGG analysis, and NFATc3 among them can promote the secretion of various inflammatory cytokines. AT1-AA-induced upregulation of miR-339-3p expression in vascular smooth muscle cells (VSMCs) can lead to a significant increase in NFATc3 protein level and promote vascular inflammation. Inhibition of miR-339-3p with antagomir-339-3p can significantly reverse AT1-AA-induced high expressions of IL-6, IL-1ß and TNF-α proteins in rat thoracic aorta and VSMCs. That is, AT1-AA can upregulate the expression of miR-339-3p in VSMCs, and the increased miR-339-3p targets the 5'UTR of NFATc3 mRNA to increase the protein level of NFATc3, thereby aggravating the occurrence of vascular inflammation. These findings provide new experimental evidence for the involvement of miRNAs in regulating vascular inflammatory diseases.

Carpal tunnel syndrome caused by tophi in the superficial flexor tendon: a case report.

Carpal tunnel syndrome (CTS) is the most common disease among peripheral nerve entrapment diseases. CTS is often caused by the hyperplasia of the transverse carpal ligament and edema of tissue in the carpal tunnel, resulting in compression of the median nerve. Specific manifestations of CTS include numbness, loss of skin sensation in the palm and three and a half fingers on the radial side, and decreased muscle strength; however, CTS caused by wrist tophi is very rare. To our knowledge, CTS with median nerve compression caused by tophi in the superficial flexor tendon of the index finger of the wrist has not been reported before. Here, we will report a case of CTS caused by tophi in the wrist in a 37-year-old patient with no history of gout. CTS caused by tophi is uncommon, but if the patient has high uric acid, CTS may be due to tophi.

Adiponectin improves amyloid-ß 31-35-induced circadian rhythm disorder in mice.

Adiponectin is an adipocyte-derived hormone, which is closely associated with the development of Alzheimer's disease (AD) and has potential preventive and therapeutic significance. In the present study, we explored the relationship between adiponectin and circadian rhythm disorder in AD, the effect of adiponectin on the abnormal expression of Bmal1 mRNA/protein induced by amyloid-ß protein 31-35 (Aß31-35), and the underlying mechanism of action. We found that adiponectin-knockout mice exhibited amyloid-ß deposition, circadian rhythm disorders and abnormal expression of Bmal1. Adiponectin ameliorated the abnormal expression of the Bmal1 mRNA/protein caused by Aß31-35 by inhibiting the activity of glycogen synthase kinase 3ß (GSK3ß). These results suggest that adiponectin deficiency could induce circadian rhythm disorders and abnormal expression of the Bmal1 mRNA/protein, whilst exogenous administration of adiponectin may improve Aß31-35-induced abnormal expression of Bmal1 by inhibiting the activity of GSK3ß, thus providing a novel idea for the treatment of AD.

Adiponectin up-regulates the decrease of myocardial autophagic flux induced by ß1 -adrenergic receptor autoantibody partly dependent on AMPK.

Cardiomyocytes autophagy is essential for maintaining cardiac function. Our previous studies have found that ß1 -adrenergic receptor autoantibody (ß1 -AA) induced the decreased myocardial autophagic flux, which resulted in cardiomyocyte death and cardiac dysfunction. And other studies demonstrated that ß1 -AA induced the decrease of AMPK phosphorylation, the key hub of autophagy pathway, while adiponectin up-regulated autophagic flux mediated by AMPK. However, it is not clear whether adiponectin improves the inhibition of myocardial autophagic flux induced by ß1 -AA by up-regulating the level of AMPK phosphorylation. In this study, it has been confirmed that ß1 -AA induced the decrease of AMPK phosphorylation level in both vivo and vitro. Moreover, pretreatment of cardiomyocytes with AMPK inhibitor Compound C could further reduce the autophagic flux induced by ß1 -AA. Adiponectin deficiency could aggravate the decrease of myocardial AMPK phosphorylation level, autophagic flux and cardiac function induced by ß1 -AA. Further, exogenous adiponectin could reverse the decline of AMPK phosphorylation level and autophagic flux induced by ß1 -AA and even reduce cardiomyocyte death. While pretreated with the Compound C, the adiponectin treatment did not improve the decreased autophagosome formation, but still improved the decreased autophagosome clearance induced by ß1 -AA in cardiomyocytes. This study is the first time to confirm that ß1 -AA could inhibit myocardial autophagic flux by down-regulating AMPK phosphorylation level. Adiponectin could improve the inhibition of myocardial autophagic flux induced by ß1 -AA partly dependent on AMPK, so as to provide an experimental basis for the treatment of patients with ß1 -AA-positive cardiac dysfunction.

LncRNA small nucleolar RNA host gene 8 promotes cell growth and migration of osteosarcoma in vitro and in vivo by functioning as a ceRNA of microRNA-876-5p.

Osteosarcoma (OS) is the most leading primary malignant tumor of the bone in adolescents and young adults worldwide. Increasing data have suggested that long non-coding RNA (lncRNA) small nucleolar RNA host gene 8 (SNHG8) plays a key role in the progression of various types of human malignancy. However, the roles and potential mechanisms of SNHG8 in OS remain unclear. In this study, we found that SNHG8 levels were obviously upregulated in OS tissues and cell lines. High expression of SNHG8 was significantly correlated with increased tumor size and advanced Enneking stage, and predicted a poor prognosis of OS patients. Functional assays revealed that SNHG8 knockdown inhibited OS cell growth and migration in vitro, and restrained tumor growth of OS in nude mice in vivo. Mechanistically, SNHG8 functioned as a competing endogenous RNA (ceRNA) of miR-876-5p in OS cells. Notably, knockdown of miR-876-5p reversed the inhibitory effects of SNHG8 inhibition on OS cell proliferation and migration. In conclusion, our study suggested that SNHG8 stimulates cell growth and migration of OS cells by functioning as a ceRNA of miR-876-5p, indicating SNHG8 may be served as a novel prognostic biomarker and therapeutic target for the treatment of OS.

Simvastatin inhibits the adipogenesis of bone marrow­derived mesenchymal stem cells through the downregulation of chemerin/CMKLR1 signaling.

Simvastatin is effective in the treatment of osteoporosis, partly through the inhibition of the adipogenesis of bone­marrow derived mesenchymal stem cells (BMSCs). The present study focused on the mechanisms responsible for the inhibitory effects of simvastatin on adipogenesis and examined the effects of simvastatin on the expression of peroxisome proliferator­activated receptor γ (PPARγ), chemerin, chemokine­like receptor 1 (CMKLR1), G protein­coupled receptor 1 (GPR1) and the adipocyte marker gene, adiponectin. BMSCs were isolated from 4­week­old female Sprague­Dawley (SD) rats, and adipogenesis was measured by the absorbance values at 490 nm of Oil Red O dye. The expression of each gene was evaluated by western blot analysis or reverse transcription­quantitative PCR (RT­qPCR). The expression of chemerin increased during adipogenesis, while CMKLR1 exhibited a trend towards a decreased expression. On days 7 and 14, the simvastatin­treated cells exhibited a downregulated expression of chemerin, whereas the upregulated expression of its receptor, CMKLR1 was observed. The results also revealed that CMKLR1 is required for adipogenesis and the simvastatin­mediated inhibitory effect on adipogenesis. Simvastatin regulated adipogenesis by negatively modulating chemerin­CMKLR1 signaling. Importantly, simvastatin stimulation inhibited the upregulation of PPARγ and PPARγ­mediated chemerin expression to prevent adipogenesis. Treatment with the PPARγ agonist, rosiglitazone, partially reversed the negative regulatory effects of simvastatin. On the whole, the findings of the present study demonstrate that simvastatin inhibits the adipogenesis of BMSCs through the downregulation of PPARγ and subsequently prevents the PPARγ­mediated induction of chemerin/CMKLR1 signaling.

Bone marrow-derived mesenchymal stem cells expressing the Shh transgene promotes functional recovery after spinal cord injury in rats.

Spinal cord injury (SCI) is one of the most disabling diseases. Cell-based gene therapy is becoming a major focus for the treatment of SCI. Bone marrow-derived mesenchymal stem cells (BMSCs) are a promising stem cell type useful for repairing SCI. However, the effects of BMSCs transplants are likely limited because of low transplant survival after SCI. Sonic hedgehog (Shh) is a multifunctional growth factor which can facilitate neuronal and BMSCs survival, promote axonal growth, prevent activation of the astrocyte lineage, and enhance the delivery of neurotrophic factors in BMSCs. However, treatment of SCI with Shh alone also has limited effects on recovery, because the protein is cleared quickly. In this study, we investigated the use of BMSCs overexpressing the Shh transgene (Shh-BMSCs) in the treatment of rats with SCI, which could stably secrete Shh and thereby enhance the effects of BMSCs, in an attempt to combine the advantages of Shh and BMSCs and so to promote functional recovery. After Shh-BMSCs treatment of SCI via the subarachnoid, we detected significantly greater damage recovery compared with that seen in rats treated with phosphate-buffered saline (PBS) and BMSCs. Use of Shh-BMSCs increased the expression and secretion of Shh, basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF), improved the behavioral function, enhanced the BMSCs survival, promoted the expression level of neurofilament 200 (NF200), and reduced the expression of glial fibrillary acidic protein (GFAP). Thus, our results indicated that Shh-BMSCs enhanced recovery of neurological function after SCI in rats and could be a potential valuable therapeutic intervention for SCI in humans.

Decreased autophagy in rat heart induced by anti-ß1-adrenergic receptor autoantibodies contributes to the decline in mitochondrial membrane potential.

It has been recognized that changes in mitochondrial structure plays a key role in development of cardiac dysfunction, and autophagy has been shown to exert maintenance of mitochondrial homeostasis effects. Our previous study found that anti-ß1-adrenergic receptor autoantibodies (ß1-AABs) could lead to cardiac dysfunction along with abnormalities in mitochondrial structure. The present study tested the hypothesis that ß1-AABs may induce the decline in mitochondrial membrane potential (ΔΨm) by suppression of cardiac autophagy, which contributed to cardiac dysfunction. Male adult rats were randomized to receive a vehicle or peptide corresponding to the second extracellular loop of the ß1 adrenergic receptor (ß1-AAB group, 0.4 µg/g every two weeks for 12 weeks) and treated with rapamycin (RAPA, an autophagy agonist) at 5 mg/kg/day for two days before detection. At the 4th week, 8th week and 12th week of active immunization, the rats were sacrificed and cardiac function and the levels of cardiac LC3 and Beclin-1 were detected. ΔΨm in cardiac myocytes was determined by myocardial radionuclide imaging technology and JC-1 staining. In the present study, ß1-AABs caused cardiac dysfunction, reduced ΔΨm and decreased cardiac autophagy. Treatment with RAPA markedly attenuated ß1-AABs-induced cardiac injury evidenced by recovered ΔΨm. Taken together, these results suggested that ß1-AABs exerted significant decreased ΔΨm, which may contribute to cardiac dysfunction, most likely by decreasing cardiac autophagy in vivo. Moreover, myocardial radionuclide imaging technology may be needed to assess the risk in developing cardiac dysfunction for the people who have ß1-AABs in their blood.

Valproic acid reduces autophagy and promotes functional recovery after spinal cord injury in rats.

Secondary damage is a critical determinant of the functional outcome in patients with spinal cord injury (SCI), and involves multiple mechanisms of which the most important is the loss of nerve cells mediated by multiple factors. Autophagy can result in cell death, and plays a key role in the development of SCI. It has been recognized that valproic acid (VPA) is neuroprotective in certain experimental animal models, however, the levels of autophagic changes in the process of neuroprotection by VPA treatment following SCI are still unknown. In the present study, we determined the extent of autophagy after VPA treatment in a rat model of SCI. We found that both the mRNA and protein levels of Beclin-1 and LC3 were significantly increased at 1, 2, and 6 h after SCI and peaked at 2 h; however, Western blot showed that autophagy was markedly decreased by VPA treatment at 2 h post-injury. Besides, post-SCI treatment with VPA improved the Basso-Beattie-Bresnahan scale, increased the number of ventral horn motoneurons, and reduced myelin sheath damage compared with vehicle-treated animals at 42 days after SCI. Together, our results demonstrated the characteristics of autophagy expression following SCI, and found that VPA reduced autophagy and enhanced motor function.