Signaling Mechanisms of Stem Cell Therapy for Intervertebral Disc Degeneration.

Low back pain is the leading cause of disability worldwide. Intervertebral disc degeneration (IDD) is the primary clinical risk factor for low back pain and the pathological cause of disc herniation, spinal stenosis, and spinal deformity. A possible approach to improve the clinical practice of IDD-related diseases is to incorporate biomarkers in diagnosis, therapeutic intervention, and prognosis prediction. IDD pathology is still unclear. Regarding molecular mechanisms, cellular signaling pathways constitute a complex network of signaling pathways that coordinate cell survival, proliferation, differentiation, and metabolism. Recently, stem cells have shown great potential in clinical applications for IDD. In this review, the roles of multiple signaling pathways and related stem cell treatment in IDD are summarized and described. This review seeks to investigate the mechanisms and potential therapeutic effects of stem cells in IDD and identify new therapeutic treatments for IDD-related disorders.

Oxytocin treatment for core symptoms in children with autism spectrum disorder: a systematic review and meta-analysis.

PURPOSE: The purpose of this article is to examine the efficacy of oxytocin in treating core symptoms of autism spectrum disorder (ASD) with children. METHODS: A systematic literature search was conducted to identify randomized controlled trials (RCTs) of oxytocin for the treatment of core symptoms in children with ASD. The search included studies published between January 1, 1999 and March 15, 2023, that were randomized, single or double-blinded, and included a placebo control group. Standard screening rules were applied to select relevant studies, resulting in the inclusion of five RCTs involving 486 children with ASD. RESULTS: Ultimately, a total of five RCTs, involving 486 children with ASD, were included in the review using standard screening rules.One of the included studies demonstrated a statistically significant improvement in Social Responsiveness Scale (SRS) and Repetitive Behavior Scale-Revised (RBS) scores when children with ASD were treated with oxytocin (24 IU/2 days for 6 weeks). The improvement in core symptoms persisted at the 6-month follow-up. The meta-analysis findings suggested that oxytocin might have a moderate effect in improving the core symptom of narrow interests and repetitive stereotyped behaviors in children with ASD. CONCLUSION: While the therapeutic value of oxytocin in treating core symptoms of ASD in children is not fully established, the results of this meta-analysis indicate a potential moderate effect. However, further studies with larger sample sizes and more robust RCTs are needed to directly demonstrate the efficacy of oxytocin. Future research should also focus on effect size and outcome evaluation accuracy while minimizing bias in RCT experiments.

Lumbar disc herniation in juveniles: A case-control study of MRI characteristics and etiological insights.

Lumbar disc herniation (LDH) is rare in juveniles. LDH occurring at age 20 years or younger is referred to as juvenile disc herniation (JDH). While adult LDH is regarded as an advanced stage of disc degeneration, it remains unclear why intervertebral discs rupture in youth. This study aimed to characterize magnetic resonance imaging (MRI) findings of JDH and investigate possible etiological factors. From 2013 to 2020, JDH patients and controls were identified and interviewed to assess demographics, general lifestyles, and family histories. MRIs were evaluated for disc degeneration, epiphyseal ring separation, Modic changes and endplate lesions. The relationships between JDH and suspected risk factors were examined. A total of 297 JDH patients (199 boys and 98 girls, age 17.3 ± 2.1 years) and 185 controls (age 17.1 ± 2.4 years) were studied. Age, body mass index, exposures to daily physical labor, regular exercise, and daily sitting time were similar between JDH cases and controls. A family medical history of serious back pain was more common in JDH patients than in controls (59.4% vs. 26.5%, p < 0.001), as well as family history of clinically established LDH (45.0% vs. 12.4%, p < 0.001). Epiphyseal ring separation was identified in 102 (29.2%) herniated discs in 91 (36.4%) JDH patients, while occurring in only 5 (1.4%) control participants (p < 0.001). Overall, severe disc degeneration was not a prominent finding in JDH patients. In conclusion, epiphyseal ring separation was a common magnetic resonance feature in JDH. Findings suggest a genetically mediated developmental model of JDH, rather than a model of premature disc degeneration.

Conservative Treatments for Lumbar Disc Herniation at L3-4 or L4-5 Were More Likely to Fail When Ipsilateral Foraminal Stenosis Was Present at the Caudally Adjacent Segment.

BACKGROUND: Conservative treatments are important in lumbar disc herniation (LDH), but predictors for poor outcomes are unclear. METHODS: Consecutive patients with unilateral single-level LDH at L3-4 or L4-5 were enrolled. Baseline clinical data were collected, and lumbar spine magnetic resonance imaging was evaluated. Foraminal stenosis was evaluated using Lee's approach and further categorized as absence (grade 0 and 1) or presence (grade 2 or 3). Each patient underwent conservative treatments (oral meloxicam and dexamethasone, corset, back extension exercise, physiotherapy, and manual therapy) for 6 weeks. Conservative treatments were defined as failed if a patient underwent surgery within 6 weeks or reported poor recovery at 6-week follow-up. Multivariate logistic regressions were used to examine the associations of failed conservative treatments with baseline characteristics and magnetic resonance imaging findings. RESULTS: The study included 222 patients (mean age 45.5 ± 9.8 years). Of patients, 48 (21.6%) had concurrent ipsilateral foraminal stenosis at the caudal segment, and conservative treatments failed in 39 (17.6%). At baseline, patients with LDH and caudal foraminal stenosis were older (50.79 ± 6.14 years vs. 44.10 ± 10.13 years, P < 0.001), had greater leg pain (7.06 ± 1.17 vs. 6.39 ± 1.40, P = 0.003), and had a higher rate of positive straight leg raising test (54.2% vs. 33.3%, P = 0.008) than patients without caudal foraminal stenosis. In multivariate regression, failure of conservative treatments was associated with positive straight leg raising test (odds ratio 2.26, P = 0.046), and caudal foraminal stenosis (odds ratio 3.20, P = 0.007). CONCLUSIONS: In the presence of caudal foraminal stenosis and positive SLR test, conservative treatments were more likely to fail in patients with LDH.

Mohawk impedes angiofibrosis by preventing the differentiation of tendon stem/progenitor cells into myofibroblasts.

Adult tendons heal via fibrovascular scarring with inferior biomechanical properties. Mohawk (Mkx) emerged as a pivotal actor in tenolineage commitment. However, its precise function in tendinopathy remains poorly understood. This study investigates the cellular and molecular mechanisms underlying Mkx' role in fibrovascular healing. Human samples were collected to test fibrovascular markers. We then performed RNAseq on Mkx-/- mice compared to their wild type littermates to decipher Mkx regulome. We therefore sought to reproduce TSPCs transition to myofibroblasts in-vitro by over-expressing MyoD and followed by phenotypic and experimental cells' characterization using microscopy, qRT-PCR, flow cytometry sorting, presto-blue cell viability assay and immunofluorescence. Two different in vivo models were used to assess the effect of the MyoD-expressing myofibroblasts: transplantation in the dorsal area of immunodeficient mice and in an adult Achilles tendon injury model. To prevent angiofibrosis, we tested the molecule Xav939 and proceeded with histological stainings, q-RT PCR transcriptional quantification of angifibrotic markers, mechanical tests, and immunofluorescence. Tendinopathy samples showed fibrovascular healing with decreased tenolineage phenotype. Transcriptomic analysis of Mkx-/- tendons revealed myofibroblast-associated biological processes. Over-expression of MyoD in WT tendon stem progenitor cells (TSPCs) gave rise to myofibroblasts reprogramming in-vitro and fibrovascular scarring in-vivo. MKX directly binds to MyoD promoter and underlies global regulative processes related to angiogenesis and Wnt signaling pathway. Blocking Wnt signaling with the small molecule Xav393 resulted in higher histological and biomechanical properties. Taken together, our data provide the first in vivo and in-vitro evidence of tendon stem progenitor cells to myofibroblasts transition and show improved tendon healing via angiofibrosis modulation, thus opening potential therapeutic avenues to treat tendinopathy patients.

MCAM is associated with metastasis and poor prognosis in osteosarcoma by modulating tumor cell migration.

BACKGROUND: Although there are standard treatment options for osteosarcoma (OS), the prognoses of patients with OS remain varied. Therefore, it is important to profile OS patients at a high risk of mortality to develop focused interventions. Although tumor biomarkers are closely associated with clinical outcomes, data on prognostic biomarkers for OS remain scarce. METHODS: We collected RNA expression profiles and clinical data of 90 OS patients from the GEO database (dataset GSE21257 and GSE39055) and 96 patients in the TARGET program. The data were analyzed using univariate Kaplan-Meier survival analysis to screen candidate gene sets that might be associated with OS survival. RESULTS: Our analysis demonstrated that melanoma cell adhesion molecule (MCAM) was associated with overall survival of patients with OS in the three cohorts. The data showed that MCAM was upregulated in OS patients who had metastases within 5 years compared to those without metastases. GO analysis revealed that genes correlated with MCAM were mainly involved in cell migration and wound healing processes. In addition, wound healing assays and gene set enrichment analysis results from RNA sequencing data of small interfering (si)-MCAM-transfected OS cells demonstrated that MCAM modulated tumor cell migration. CONCLUSIONS: Our data demonstrate that MCAM may be a novel prognostic biomarker for OS. MCAM is associated with increased cell migration ability and risk of metastasis, thus leading to poor prognoses in OS patients.

Association between social supports and negative emotions among pediatric residents in China: The chain-mediating role of psychological resilience and burnout.

Background: Chinese pediatricians are facing challenges, and there is a need to examine the issue of negative emotions, namely, stress, anxiety and depression, among front-line pediatric residents in clinical settings. Understanding the current situation and influencing factors of negative emotions among pediatric residents in China and exploring the formation mechanism can lay a foundation for psychological interventions. Methods: A total of 138 pediatric residents in the Children's Hospital, Zhejiang University School of Medicine, China, were surveyed using the Depression Anxiety Stress Scale-21 (DASS-21), Social Support Rating Scale (SSRS), Connor-Davidson Resilience Scale (CD-RISC), and Maslach Burnout Inventory-General Survey (MBI-GS). Results: (1) The incidence of abnormal stress, anxiety, and depression among pediatric residents was 18.8%, 47.8%, and 47.8% respectively. (2) Negative emotions were significantly negatively correlated with social supports and psychological resilience, and positively correlated with burnout. (3) The chain-mediating effect of resilience and burnout between social supports and negative emotions was significant. Conclusion: Psychological resilience and burnout played a chain-mediating role between social supports and negative emotions. Measures should be taken to improve the mental health of Chinese pediatric residents.

A promising prognostic signature for lung adenocarcinoma (LUAD) patients basing on 6 hypoxia-related genes.

BACKGROUND: Hypoxia signaling plays a critical role in the development of lung adenocarcinoma (LUAD). We herein aimed to explore the prognostic value of hypoxia-related genes and construct the hypoxia-related prognostic signature for LUAD patients. METHODS: A total of 26 hypoxia-related genes were collected. Five hundred thirteen and 246 LUAD samples were obtained from the Cancer Genome Atlas and Gene Expression Omnibus databases, respectively. Univariate Cox regression and LASSO Cox regression analyses were conducted to screen the hypoxia-related genes associated with the prognosis of LUAD patients, which would be used for constructing prognosis predictive model for LUAD patients. Multivariate Cox regression analysis was done to determine the independent prognostic factors. The Nomogram model was constructed to predict the prognosis of LUAD patients. RESULTS: Based on 26 hypoxia-related genes, LUAD samples could be divided into 4 clusters with different prognoses. Among which, 6 genes were included to construct the Risk Score and the LUAD patients with higher Risk Score had worse prognosis. Besides, the Nomogram based on all the independent risk factors could relatively reliably predict the survival probability. And 9 types of immune cells' infiltration was significantly differential between high and low risk LUAD patients. CONCLUSION: The Risk Score model based on the 6 crucial hypoxia-related genes could relatively reliably predict the prognosis of LUAD patients.

Broadband electrical impedance as a novel characterization of oxidative stress in single L6 skeletal muscle cells.

Oxidative stress (OS) is one of the leading causes of cytotoxicity and is linked to many human physio-pathological conditions. In particular, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) induced by OS is debilitating to quality of life, while no clear biological markers have been identified for diagnostic measures. Recently, impedance measurements of peripheral blood cells of ME/CFS patients have been shown as a promising approach to diagnose the disease. Inspired by this study and aiming to interrogate muscle cells directly, we investigated if broadband measurements of single muscle cells could differentiate normal and oxidatively stressed cell populations. We first optimized a protocol through H2O2 treatment to introduce oxidative stress to cultured rat L6 skeletal muscle cells. The treated cells were further characterized through broadband impedance spectroscopy of single cells using a microfluidic lab-on-a-chip system. The resulting dielectric properties of cytoplasm permittivity and conductivity are electrically distinct from normally cultured cells. The reflection and transmission coefficients, ΔS11 and ΔS21, of the normal cells are tightly clustered and closely resemble those of the cell-free solution across the frequency range of 9 kHz to 9 GHz. On the other hand, dielectric properties of the oxidized cells have a wide distribution in the GHz range, deviating both in the positive and negative directions from the normally cultured cells. Simulation results guide our hypothesis that the dielectric differences could be linked to ion alterations, while calcium imaging directly supports the contribution of calcium flux to the observed deviation of S parameters. The unique electrical profile associated with oxidized cells in the GHz frequencies provide a framework for future development of technologies to diagnose oxidative-stress related diseases such as ME/CFS.

T851I mutation of human large tumor suppressor 1 disrupts its kinase activity and tumor-suppressor functions.

AIM: Large tumor suppressor 1 (LATS1) is a Ser/Thr kinase to mediate Hippo signaling pathway and plays a pivotal role in tumor suppression. By searching the COSMIC database, we found a somatic missense mutation (NM_004690.4:c.2552C>T) of human LATS1 (NP_004681.1:p.851T>I) in two colorectal cancer cell lines, and investigated the role and underlying mechanism of this mutation in the colorectal tumorigenesis. MAIN METHODS: We performed structural and biochemistry analyses to investigate the role of LATS1 T851I mutation in Hippo signaling activation and used the mouse xenograft model to assess the role of this mutation in the colorectal tumorigenesis. KEY FINDINGS: By structural and biochemistry approaches, we propose that T851 is an active residue other than Ser909 on the activation loop and is essential for LATS1 phosphorylation and kinase activity. We then reveal that T851I mutation in LATS1 not only destabilizes the phospho-Thr1079-LATS1, a prerequisite of LATS1 kinase activity, but also reduces its binding to the downstream effectors, YAP and TAZ. As a result, T851I mutation in LATS1 attenuates Hippo signaling and decreases its tumor-suppressor functions in the colorectal cancer. SIGNIFICANCE: The present study identifies the T851 as an essential residue for LATS1 kinase activity and uncovers the T851I mutation of LATS1 and consequent Hippo signaling suppression as a hitherto uncharacterized mechanism controlling colorectal tumorigenesis.

Broadband Electrical Sensing of a Live Biological Cell with In Situ Single-Connection Calibration.

Single-connection in situ calibration using biocompatible solutions is demonstrated in single-cell sensing from 0.5 to 9 GHz. The sensing is based on quickly trapping and releasing a live cell by dielectrophoresis on a coplanar transmission line with a little protrusion in one of its ground electrodes. The same transmission line is used as the calibration standard when covered by various solutions of known permittivities. The results show that the calibration technique may be precise enough to differentiate cells of different nucleus sizes, despite the measured difference being less than 0.01 dB in the deembedded scattering parameters. With better accuracy and throughput, the calibration technique may allow broadband electrical sensing of live cells in a high-throughput cytometer.

High-Resolution Dissection of Chemical Reprogramming from Mouse Embryonic Fibroblasts into Fibrocartilaginous Cells.

Articular cartilage injury and degeneration causing pain and loss of quality-of-life has become a serious problem for increasingly aged populations. Given the poor self-renewal of adult human chondrocytes, alternative functional cell sources are needed. Direct reprogramming by small molecules potentially offers an oncogene-free and cost-effective approach to generate chondrocytes, but has yet to be investigated. Here, we directly reprogrammed mouse embryonic fibroblasts into PRG4+ chondrocytes using a 3D system with a chemical cocktail, VCRTc (valproic acid, CHIR98014, Repsox, TTNPB, and celecoxib). Using single-cell transcriptomics, we revealed the inhibition of fibroblast features and activation of chondrogenesis pathways in early reprograming, and the intermediate cellular process resembling cartilage development. The in vivo implantation of chemical-induced chondrocytes at defective articular surfaces promoted defect healing and rescued 63.4% of mechanical function loss. Our approach directly converts fibroblasts into functional cartilaginous cells, and also provides insights into potential pharmacological strategies for future cartilage regeneration.

Ezh2 Ameliorates Osteoarthritis by Activating TNFSF13B.

Epigenetic regulation is highly correlated with osteoarthritis (OA) development, whereas its role and detailed mechanisms remain elusive. In this study, we explored the expression of EZH2, an H3K27me3 transferase, in human OA cartilages and its roles in regulating OA pathogenesis. Here, we found EZH2 was highly expressed in both mice and human OA cartilage samples by using histological analysis and RNA sequencing (RNA-Seq). The medial meniscectomy (MMx) OA model results indicated the conditional knockout of Ezh2 deteriorated OA pathological conditions. Furthermore, we showed the positive role of Ezh2 in cartilage wound healing and inhibition of hypertrophy through activating TNFSF13B, a member of the tumor necrosis factor superfamily. Further, we also indicated that the effect of TNFSF13B, increased by Ezh2, might boost the healing of chondrocytes through increasing the phosphorylation of Akt. Taken together, our results uncovered an EZH2-positive subpopulation existed in OA patients, and that EZH2-TNFSF13B signaling was responsible for regulating chondrocyte healing and hypertrophy. Thus, EZH2 might act as a new potential target for OA diagnosis and treatment. © 2020 American Society for Bone and Mineral Research.

Correlation Between Optical Fluorescence and Microwave Transmission During Single-Cell Electroporation.

OBJECTIVE: Multimodal characterization of a mammalian cell by optical and microwave techniques simultaneously during electroporation. METHODS: Using a coplanar waveguide with a Jurkat cell trapped in the middle of its center conductor, continuous waves at 100 kHz of different amplitudes were applied for 20 s, while microwave transmission coefficients at 9 GHz were measured every 0.4 s. RESULTS: The onset of electroporation was indicated by abrupt changes in both fluorescence intensity and transmission coefficient. Additionally, in measurements that lasted 300 s, the transmission coefficient was found to recover to the pre-poration level, while the fluorescence intensity remained different. Since the cells were confirmed viable through post-poration staining, the recovery of the transmission coefficient suggested reversible electroporation. CONCLUSION: These experimental results showed that the transmission coefficient could serve as a label-free indicator of cell membrane permeability during and after electroporation. Furthermore, it could be used to expeditiously differentiate reversible electroporation from the irreversible one. SIGNIFICANCE: This study should aid fundamental analysis of cell physiology, as well as molecular delivery, in cell engineering and electrotherapy.

[Correlation between histone methylation level and pathological development of osteoarthritis].

Osteoarthritis is the most common degenerative cartilage disease. A large number of studies have shown the close association between epigenetics and osteoarthritis. Histone methylation is a type of epigenetic modification, and the link between histone methylation and osteoarthritis has also been revealed. In this article, we summarize the correlation between methylation levels of different histones and osteoarthritis in an attempt to explore the changes and regulation mechanisms of histone methylation in osteoarthritis. It has been shown that there are possible relations between the methylation levels of different amino acids on histone H3 and the pathological development of osteoarthritis; specifically, the rise of methylation level at the lysine 4 would aggravate the pathological development of osteoarthritis, while the the pattern of lysine 9 and 27 would be the opposite. These results indicate the possible existence of a complex network of histone methylation modifications. And the specific regulation of histone methylation levels in different positions may delay or prevent the occurrence and development of osteoarthritis.