Vertebral bone quality score was associated with paraspinal muscles fat infiltration, but not modic classification in patients with chronic low back pain: a prospective cross-sectional study.

BACKGROUND: The lumbar vertebra and paraspinal muscles play an important role in maintaining the stability of the lumbar spine. Therefore, the aim of this study was to investigate the relationship between paraspinal muscles fat infiltration and vertebral body related changes [vertebral bone quality (VBQ) score and Modic changes (MCs)] in patients with chronic low back pain (CLBP). METHODS: Patients with CLBP were prospectively collected in four hospitals and all patients underwent 3.0T magnetic resonance scanning. Basic clinical information was collected, including age, sex, course of disease (COD), and body mass index (BMI). MCs were divided into 3 types based on their signal intensity on T1 and T2-weighted imaging. VBQ was obtained by midsagittal T1-weighted imaging (T1WI) and calculated using the formula: SIL1-4/SICSF. The Proton density fat fraction (PDFF) values and cross-sectional area (CSA) of paraspinal muscles were measured on the fat fraction map from the iterative decomposition of water and fat with the echo asymmetry and least-squares estimation quantitation (IDEAL-IQ) sequences and in/out phase images at the central level of the L4/5 and L5/S1 discs. RESULTS: This study included 476 patients with CLBP, including 189 males and 287 females. 69% had no Modic changes and 31% had Modic changes. There was no difference in CSA and PDFF for multifidus(MF) and erector spinae (ES) at both levels between Modic type I and type II, all P values>0.05. Spearman correlation analysis showed that VBQ was weakly negatively correlated with paraspinal muscles CSA (all r values < 0.3 and all p values < 0.05), moderately positive correlation with PDFF of MF at L4/5 level (r values = 0.304, p values<0.001) and weakly positively correlated with PDFF of other muscles (all r values<0.3 and all p values<0.001). Multivariate linear regression analysis showed that age (ß = 0.141, p < 0.001), gender (ß = 4.285, p < 0.001) and VBQ (ß = 1.310, p = 0.001) were related to the total PDFF of muscles. For MCs, binary logistic regression showed that the odds ratio values of age, BMI and COD were 1.092, 1.082 and 1.004, respectively (all p values ＜ 0.05). CONCLUSIONS: PDFF of paraspinal muscles was not associated with Modic classification. In addition to age and gender, PDFF of paraspinal muscles is also affected by VBQ. Age and BMI are considered risk factors for the MCs in CLBP patients.

Multidimensional risk factor analysis of acute low back pain progressing to chronicity: a longitudinal cohort study protocol.

Introduction: Approximately 40% of patients with acute low back pain (LBP) develop chronic low back pain, which significantly increases the risk of poor prognosis. To reduce the risk of acute LBP becoming chronic, effective preventive strategies are needed. Early identification of risk factors for the development of chronic LBP can help clinicians choose appropriate treatment options and improve patient outcomes. However, previous screening tools have not considered medical imaging findings. The aim of this study is to identify factors that can predict the risk of acute LBP becoming chronic based on clinical information, pain and disability assessment, and MRI imaging findings. This protocol describes the methodology and plan for investigating multidimensional risk factors for acute LBP becoming chronic, in order to better understand the development of acute LBP and prevent chronic LBP. Methods: This is a prospective multicenter study. We plan to recruit 1,000 adult patients with acute low back pain from four centers. In order to select four representative centers, we find the larger hospitals from different regions in Yunnan Province. The study will use a longitudinal cohort design. Patients will undergo baseline assessments upon admission and will be followed up for 5 years to collect the time of chronicity and associated risk factors. Upon admission, patients will be collected detailed demographic information, subjective and objective pain scores, disability scale, and lumbar spine MRI scanning. In addition, patient's medical history, lifestyle, psychological factors will be collected. Patients will be followed up at 3 months, 6 months, 1 year, 2 years and up for 5 years after admission to collect the time of chronicity and associated factors. Multivariate analysis will be used to explore the multidimensional risk factors affecting the chronicity of acute LBP patients (such as age, gender, BMI, degree of intervertebral disc degeneration, etc.), and survival analysis will be performed to explore the impact of each factor on the time of chronicity. Ethics and dissemination: The study has been approved by the institutional research ethics committee of each study center (main center number: 2022-L-305). Results will be disseminated through scientific conferences and peer-reviewed publications, as well as meetings with stakeholders.

Periplogenin Activates ROS-ER Stress Pathway to Trigger Apoptosis via BIP-eIF2α- CHOP and IRE1α-ASK1-JNK Signaling Routes.

BACKGROUND: Periplogenin (PPG), a natural compound isolated from traditional Chinese herb Cortex Periplocae, has been reported to possess anti-inflammatory and anti-cancer properties. OBJECTIVE: The present study aims to investigate the antitumor effects of PPG and the underlying mechanism in human colorectal cancer cells. METHODS: The inhibition of cell growth in vitro was assessed by MTT assay. The induction of apoptosis and the ROS production induced by PPG was investigated by flow cytometry analysis. Western blotting was applied to measure the protein expression. Small interference RNA (siRNA) and a specific pharmacological inhibitor were used to knock down or inhibit the expression of related genes. RESULTS: PPG was able to cause the production of ROS, inhibit the cancer cell growth and induce apoptosis. Nacetylcysteine was able to inhibit ROS production and apoptosis. PPG up-regulated the protein levels of BIP, peIF2α and CHOP as well as IRE1α and p-JNK, and down-regulated the protein level of p-ASK1, all of which were reversed by N-acetylcysteine. Importantly, knockdown of CHOP or JNK protein level attenuated the PPGelicited apoptosis. CONCLUSION: PPG-induced apoptosis was regulated by ROS-mediated BIP/eIF2α/CHOP and BIP/ASK1/JNK signaling pathways in colon cancer cells, suggesting that PPG is a promising therapeutic agent for the treatment of human colon cancer.

Predicting human disease-associated circRNAs based on locality-constrained linear coding.

Circular RNAs (circRNAs) are a new kind of endogenous non-coding RNAs, which have been discovered continuously. More and more studies have shown that circRNAs are related to the occurrence and development of human diseases. Identification of circRNAs associated with diseases can contribute to understand the pathogenesis, diagnosis and treatment of diseases. However, experimental methods of circRNA prediction remain expensive and time-consuming. Therefore, it is urgent to propose novel computational methods for the prediction of circRNA-disease associations. In this study, we develop a computational method called LLCDC that integrates the known circRNA-disease associations, circRNA semantic similarity network, disease semantic similarity network, reconstructed circRNA similarity network, and reconstructed disease similarity network to predict circRNAs related to human diseases. Specifically, the reconstructed similarity networks are obtained by using Locality-Constrained Linear Coding (LLC) on the known association matrix, cosine similarities of circRNAs and diseases. Then, the label propagation method is applied to the similarity networks, and four relevant score matrices are respectively obtained. Finally, we use 5-fold cross validation (5-fold CV) to evaluate the performance of LLCDC, and the AUC value of the method is 0.9177, indicating that our method performs better than the other three methods. In addition, case studies on gastric cancer, breast cancer and papillary thyroid carcinoma further verify the reliability of our method in predicting disease-associated circRNAs.

Integrating Bipartite Network Projection and KATZ Measure to Identify Novel CircRNA-Disease Associations.

Accumulating biological experiments have shown that circRNAs are closely related to the occurrence and development of many complex human diseases. During recent years, the associations of circRNA with disease have caused more and more researchers to pay attention and to analyze their correlation mechanisms. However, experimental methods for determining the associations of circRNA with a particular disease are still expensive, difficult, and time consuming. Moreover, the available databases related to circRNA-disease correlations have only recently been updated, and only a few computational methods are constructed to predict potential circRNA-disease correlations. Taking into account the limitations of experimental studies, we develop a novel computational method, named IBNPKATZ, for predicting potential circRNA-disease associations, which integrates the bipartite network projection algorithm and KATZ measure. This model is based on the known circRNA-disease associations, combining circRNA similarity and disease similarity. Specifically, the circRNA similarity is derived from the average of the semantic similarity and the Gaussian interaction profile (GIP) kernel similarity of circRNA. Similarly, disease similarity is the mean of the semantic similarity and the GIP kernel similarity of disease. Furthermore, it is semi-supervised and does not require negative samples. Finally, IBNPKATZ achieves reliable AUC of 0.9352 in the leave-one-out cross validation, and case studies show that the circRNA-disease correlations predicted by our method can be successfully demonstrated by relevant experiments. The IBNPKATZ is expected to be a useful biomedical research tool for predicting potential circRNA-disease associations.

[High frequency electrical stimulation of sciatic nerve enhances skeletal muscle autophagy in mice].

The aim of the present study was to investigate the effects of exercise on skeletal muscle autophagy. Trains of high-frequency electrical stimulation (pulses frequency: 100 Hz) were used to stimulate sciatic nerve and consequently induce muscle contraction of the left hindlimb. The unstimulated right hindlimb muscles were taken as control. The mice were sacrificed immediately (0), 30 or 60 min after the electrical stimulation by cervical dislocation, and gastrocnemius muscles were rapidly dissected and freeze-clamped in liquid nitrogen. AMP-activated protein kinase (AMPK) and the autophagy marker protein LC3 were detected by Western blotting, and muscle atrophy related genes including atrogin-1, MuRF-1, Bnip3, Bnip3l and CathepsinL were detected by using real-time qPCR. The results showed that, at 0 min after the electrical stimulation, the activity of AMPK and LC3-II/I ratio were significantly increased in left gastrocnemius muscles, compared with those of the muscles in the right hindlimb. The levels of atrogin-1, MuRF-1, Bnip3, Bnip3l and CathepsinL mRNA expressions were up-regulated by electrical stimulation. Meanwhile, the activity of autophagy related protein, ULK1 was significantly enhanced by electrical stimulation. These results suggest that electrical stimulation of sciatic nerve may induce the skeletal muscle autophagy, and this may be regulated through AMPK/ULK1-mediated signaling pathway.

Levistolide A Induces Apoptosis via ROS-Mediated ER Stress Pathway in Colon Cancer Cells.

BACKGROUND/AIMS: Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Levistolide A (LA), a natural compound isolated from the traditional Chinese herb Ligusticum chuanxiong Hort, is used for treating cancer. In this study, we investigated the anticancer effect of LA in HCT116 and its isogenic p53-/- colon cancer cells, as well as the underlying mechanisms. METHODS: MTT assay was used to evaluate the effect of LA on the viability of cancer cells. Apoptosis and reactive oxygen species (ROS) production by the cells were determined by flow cytometry. Protein expression was detected by western blotting. RESULTS: The results showed that LA inhibited viability and caused apoptosis of both wild-type and p53-/- HCT116 cells. LA was able to trigger production of ROS and endoplasmic reticulum (ER) stress. Inhibition of ROS using N-acetylcysteine abrogated LA-induced ER stress and apoptosis, as well as the reduction in cancer cell viability. CONCLUSION: Our results indicate that LA causes apoptosis of colon cancer cells via ROS-mediated ER stress pathway. It will be interesting to develop the natural compound for chemotherapy of cancers such as CRC.

Suppression of mTORC1 activation in acid-α-glucosidase-deficient cells and mice is ameliorated by leucine supplementation.

Pompe disease is due to a deficiency in acid-α-glucosidase (GAA) and results in debilitating skeletal muscle wasting, characterized by the accumulation of glycogen and autophagic vesicles. Given the role of lysosomes as a platform for mTORC1 activation, we examined mTORC1 activity in models of Pompe disease. GAA-knockdown C2C12 myoblasts and GAA-deficient human skin fibroblasts of infantile Pompe patients were found to have decreased mTORC1 activation. Treatment with the cell-permeable leucine analog L-leucyl-L-leucine methyl ester restored mTORC1 activation. In vivo, Pompe mice also displayed reduced basal and leucine-stimulated mTORC1 activation in skeletal muscle, whereas treatment with a combination of insulin and leucine normalized mTORC1 activation. Chronic leucine feeding restored basal and leucine-stimulated mTORC1 activation, while partially protecting Pompe mice from developing kyphosis and the decline in muscle mass. Leucine-treated Pompe mice showed increased spontaneous activity and running capacity, with reduced muscle protein breakdown and glycogen accumulation. Together, these data demonstrate that GAA deficiency results in reduced mTORC1 activation that is partly responsible for the skeletal muscle wasting phenotype. Moreover, mTORC1 stimulation by dietary leucine supplementation prevented some of the detrimental skeletal muscle dysfunction that occurs in the Pompe disease mouse model.

Alteration of de novo glucose production contributes to fasting hypoglycaemia in Fyn deficient mice.

Previous studies have demonstrated that glucose disposal is increased in the Fyn knockout (FynKO) mice due to increased insulin sensitivity. FynKO mice also display fasting hypoglycaemia despite decreased insulin levels, which suggested that hepatic glucose production was unable to compensate for the increased basal glucose utilization. The present study investigates the basis for the reduction in plasma glucose levels and the reduced ability for the liver to produce glucose in response to gluconeogenic substrates. FynKO mice had a 5-fold reduction in phosphoenolpyruvate carboxykinase (PEPCK) gene and protein expression and a marked reduction in pyruvate, pyruvate/lactate-stimulated glucose output. Remarkably, de novo glucose production was also blunted using gluconeogenic substrates that bypass the PEPCK step. Impaired conversion of glycerol to glucose was observed in both glycerol tolerance test and determination of the conversion of (13)C-glycerol to glucose in the fasted state. α-glycerol phosphate levels were reduced but glycerol kinase protein expression levels were not changed. Fructose-driven glucose production was also diminished without alteration of fructokinase expression levels. The normal levels of dihydroxyacetone phosphate and glyceraldehyde-3-phosphate observed in the FynKO liver extracts suggested normal triose kinase function. Fructose-bisphosphate aldolase (aldolase) mRNA or protein levels were normal in the Fyn-deficient livers, however, there was a large reduction in liver fructose-6-phosphate (30-fold) and fructose-1,6-bisphosphate (7-fold) levels as well as a reduction in glucose-6-phosphate (2-fold) levels. These data suggest a mechanistic defect in the allosteric regulation of aldolase activity.

Accumulation of ß-catenin by lithium chloride in porcine myoblast cultures accelerates cell differentiation.

The Wnt/ß-catenin signaling pathway regulates cell proliferation and differentiation to determine cell fate during embryogenesis. Lithium chloride (LiCl) is known to activate canonical Wnt signaling by inhibiting glycogen synthetase kinase-3ß and consequently stabilizing free cytosolic ß-catenin. To understand the role of the Wnt/ß-catenin pathway in the regulation of porcine myoblast differentiation, we studied the effects of LiCl on cultured porcine myoblasts and ß-catenin expression. A supplementation of 25 mM LiCl induced myoblast differentiation into myotubes over 3 days of culture. By semi-quantitative RT-PCR analyses, levels of mRNA encoding MyoD, Myogenin, Myf5 and several Wnt-responsive genes in the cultured myoblast cells were significantly increased after LiCl treatment. Using Western blotting and immunofluorescence analysis, we found that the protein levels of ß-catenin were consistently increased by LiCl. Meanwhile, phosphorylated GSK-3ß at Ser9 levels were also increased as an indicator of GSK-3ß inactivation. Additionally, the nuclear staining of endogenous ß-catenin was also significantly increased in porcine myoblasts 48 h after LiCl treatment. These results provided additional evidence that Wnt/ß-catenin is a significant pathway that regulates myogenic differentiation. An enhanced level of ß-catenin plays a positive role in porcine myoblast differentiation.

Beta-catenin protein utilized by Tumour necrosis factor-alpha in porcine preadipocytes to suppress differentiation.

The Wnt/beta-catenin signaling pathway alters adipocyte differentiation by inhibiting adipogenic gene expression. beta-catenin plays a central role in the Wnt/beta-catenin signaling pathway. In this study, we revealed that tumour necrosis factor-alpha (TNF-alpha), a potential negative regulator of adipocyte differentiation, inhibits porcine adipogenesis through activation of the Wnt/beta-catenin signaling pathway. Under the optimal concentration of TNF-alpha, the intracellular beta-catenin protein was stabilized. Thus, the intracellular lipid accumulation of porcine preadipocyte was suppressed and the expression of important adipocyte marker genes, including peroxisome proliferator-activated receptor-gamma (PPARgamma) and CCAAT/enhancer binding protein-alpha (C/EBPalpha), were inhibited. However, a loss of beta-catenin in porcine preadipocytes enhanced the adipogenic differentiation and attenuated TNF-alpha induced anti-adipogenesis. Taken together, this study indicated that TNF-alpha inhibits adipogenesis through stabilization of beta-catenin protein in porcine preadipocytes.

Roles of Wnt/beta-catenin signaling in adipogenic differentiation potential of adipose-derived mesenchymal stem cells.

Wnt/beta-catenin signaling pathway controls differentiation of various cells by regulating the expression of target genes. beta-Catenin plays a central role in Wnt/beta-catenin signaling pathway. To investigate the molecular mechanisms of fate determination in adipose-derived mesenchymal stem cells (AMSCs), we investigated effects of Wnt3a and beta-catenin, two key members of the Wnt/beta-catenin signaling, in adipogenic differentiation of porcine AMSCs. We demonstrated that Wnt3a protein can inhibit the adipogenic differentiation of porcine AMSCs in vitro culture. By stabilization of cytoplasmic beta-catenin with continuous treatment by LiCl, the adipogenic differentiation of AMSCs was also suppressed and the osteogenesis was stimulated. In contrast, a loss of beta-catenin in AMSCs enhanced the adipogenic differentiation and rescued LiCl-induced anti-adipogenesis. In addition, the mutual activation of CCAAT/enhancer-binding protein-alpha (C/EBPalpha) and peroxisome proliferator-activated receptor-gamma (PPARgamma) were repressed in the presence of Wnt3a or LiCl, but increased in the gene silencing of beta-catenin. Taken together, our study indicated that Wnt/beta-catenin signaling pathway inhibited the adipogenic differentiation potential and alter the cell fate from adipocytes to osteoblasts.