A LATS2 and ALKBH5 positive feedback loop supports their oncogenic roles.

N(6)-methyladenosine (m6A) critically regulates RNA dynamics in various biological processes. The m6A demethylase ALKBH5 promotes tumorigenesis of glioblastoma, while the intricate web that orchestrates its regulation remains enigmatic. Here, we discover that cell density affects ALKBH5 subcellular localization and m6A dynamics. Mechanistically, ALKBH5 is phosphorylated by the large tumor suppressor kinase 2 (LATS2), preventing its nuclear export and enhancing protein stability. Furthermore, phosphorylated ALKBH5 reciprocally erases m6A from LATS2 mRNA, thereby stabilizing this transcript. Unexpectedly, LATS2 depletion suppresses glioblastoma stem cell self-renewal independent of yes-associated protein activation. Additionally, deficiency in either LATS2 or ALKBH5 phosphorylation impedes tumor progression in mouse xenograft models. Moreover, high levels of LATS2 expression and ALKBH5 phosphorylation are associated with tumor malignancy in patients with gliomas. Collectively, our study unveils an oncogenic positive feedback loop between LATS2 and ALKBH5, revealing a non-canonical branch of the Hippo pathway for RNA processing and suggesting potential anti-cancer interventions.

A Study on Interobserver and Intraobserver Reliability of the Huashan Radiologic Classification System for Cervical Spinal Cord Injury Without Fracture and Dislocation.

STUDY DESIGN: Observational study. OBJECTIVE: To assess the reproducibility and reliability of the system. BACKGROUND: The Huashan radiologic classification system for cervical spinal cord injury without fracture and dislocation (CSCIWFD) was recently proposed and found useful for clinical practice. PATIENTS AND METHODS: Patients diagnosed with CSCIWFD between 2015 and 2021 were recruited. Six spine surgeons from different institutions, three experienced and other inexperienced respectively, were trained as observers of the system, and these surgeons classified the recruited patients using the system. Then, 8 weeks later, they repeated the classification on the same patients in a different order. The interobserver and intraobserver agreement between the results was analyzed using percentage agreement, weighted kappa, and Cohen kappa (κ) statistics. RESULTS: A total of 60 patients were included in the analysis. Type I was the most frequent type (29 cases, 48.3%), followed by type II (13 cases, 21.7%), type III (12 cases, 20%), and type IV (6 cases, 10%). For all the observers, experienced observers, and inexperienced observers, the overall agreement percentages were 77.6% (κ = 0.78), 84.4% (κ = 0.84), and 72.8% (κ = 0.74), respectively, indicating substantial to nearly perfect interobserver reproducibility. A higher level of agreement was found for differentiating type I from other types, with the percentage agreement ranging from 87.8% to 94.4% (κ= 0.74-0.88). For distinguishing compression on the spinal cord (types I and II vs types III and IV) among the different groups of observers, the percentage agreement was 97.8% (κ = 0.94), indicating nearly perfect reproducibility. As for intraobserver agreement, the percentage agreement ranged from 86.7% to 96.7% (κ = 0.78-0.95), indicating at least substantial reliability. CONCLUSIONS: The Huashan radiologic classification system for CSCIWFD was easy to learn and apply in a clinical environment, showing excellent reproducibility and reliability. Therefore, it would be promising to apply and promote this system for the precise evaluation and personalized treatment strategy.

Metformin rejuvenates Nap1l2-impaired immunomodulation of bone marrow mesenchymal stem cells via metabolic reprogramming.

Ageing and cell senescence of mesenchymal stem cells (MSCs) limited their immunomodulation properties and therapeutic application. We previously reported that nucleosome assembly protein 1-like 2 (Nap1l2) contributes to MSCs senescence and osteogenic differentiation. Here, we sought to evaluate whether Nap1l2 impairs the immunomodulatory properties of MSCs and find a way to rescue the deficient properties. We demonstrated that metformin could rescue the impaired migration properties and T cell regulation properties of OE-Nap1l2 BMSCs. Moreover, metformin could improve the impaired therapeutic efficacy of OE-Nap1l2 BMSCs in the treatment of colitis and experimental autoimmune encephalomyelitis in mice. Mechanistically, metformin was capable of upregulating the activation of AMPK, synthesis of l-arginine and expression of inducible nitric oxide synthase in OE-Nap1l2 BMSCs, leading to an increasing level of nitric oxide. This study indicated that Nap1l2 negatively regulated the immunomodulatory properties of BMSCs and that the impaired functions could be rescued by metformin pretreatment via metabolic reprogramming. This strategy might serve as a practical therapeutic option to rescue impaired MSCs functions for further application.

Protein Crotonylation Promotes Osteogenic Differentiation of Periodontal Ligament Stem Cells via the PI3K-AKT Pathway.

Posttranslational modifications (PTMs) are crucial regulatory mechanisms for cellular differentiation and organismal development. Acylation modification is one of the main PTMs that plays a pivotal role in regulating the osteogenic differentiation of mesenchymal stem cells and is a focal point of research in bone tissue regeneration. However, its mechanism remains incompletely understood. This article aims to investigate the impact of protein crotonylation on osteogenic differentiation in periodontal ligament stem cells (PDLSCs) and elucidate its underlying mechanisms. Western blot analysis identified that the modification level of acetylation, crotonylation, and succinylation were significantly upregulated after osteogenic induction of PDLSCs. Subsequently, sodium crotonate (NaCr) was added to the medium and acyl-CoA synthetase short-chain family member 2 (ACSS2) was knocked down by short hairpin RNA plasmids to regulate the total level of protein crotonylation. The results indicated that treatment with NaCr promoted the expression of osteogenic differentiation-related factors in PDLSCs, whereas silencing ACSS2 had the opposite effect. In addition, mass spectrometry analysis was used to investigate the comprehensive analysis of proteome-wide crotonylation in PDLSCs under osteogenic differentiation. The analysis revealed that the level of protein crotonylation related to the PI3K-AKT signaling pathway was significantly upregulated in PDLSCs after osteogenic induction. Treatment with NaCr and silencing ACSS2 affected the activation of the PI3K-AKT signaling pathway. Collectively, our study demonstrates that protein crotonylation promotes osteogenic differentiation of PDLSCs via the PI3K-AKT pathway, providing a novel targeting therapeutic approach for bone tissue regeneration.

Role of Doping Effect and Chemical Pressure Effect Introduced by Alkali Metal Substitution on 1144 Iron-Based Superconductors.

CaAFe4As4 with A = K, Rb, and Cs are close to the doped 122 system, and the parent material can reach a superconducting transition temperature of 31-36 K without doping. To study the role of alkali metals, we investigated the induced hole doping and chemical pressure effects as a result of the introduction of alkali metals using density-functional-based methods. These two effects can affect the superconducting transition temperature by changing the number of electrons and the structure of the FeAs conductive layer, respectively. Our study shows that the dxz and dyz orbitals, which are degenerate in CaFe2As2, become nondegenerate in CaAFe4As4 due to two nonequivalent arsenic atoms (As1 and As2). The unusual oblate ellipsoid hole pocket at Γ point in CaAFe4As4 results from a divalent cation Ca2+ replaced by a monovalent cation A+. It shows one of the main differences in fermiology compared to a particular form of CaFe2As2 with reduced 1144 symmetry, due to the enhancement of As2-Fe hybridization. The unusual band appears in CaFe2As2 (1144) and gradually disappears in the change of K to Cs. Further analysis shows that this band is contributed by As1 and has strong dispersion perpendicular to the FeAs layer, suggesting that it is related to the peculiar van Hove singularity below the Fermi level. In addition, various aspects of CaFe2As2 (1144) and CaAFe4As4 in the ground state are discussed in terms of the influence of hole doping and chemical pressure.

CYLD inhibits osteoclastogenesis to ameliorate alveolar bone loss in mice with periodontitis.

Periodontitis is a chronic immune inflammatory disease that can lead to the destruction and loss of the tooth-supporting apparatus. During this process, the balance between bone absorption mediated by osteoclasts and bone formation mediated by osteoblasts is damaged. Consistent with previous studies, we observed that depletion of cylindromatosis (CYLD) resulted in an osteoporotic bone phenotype. However, the effect of CYLD deficiency on periodontitis is undetermined. Here, we investigated whether CYLD affects periodontal tissue homeostasis in experimental periodontitis in Cyld knockout (KO) mice, and we explored the underlying mechanisms. Interestingly, we discovered significant alveolar bone density loss and severely reduced alveolar bone height in Cyld KO mice with experimentally induced periodontitis. We observed increased osteoclast number and activity in both the femurs and alveolar bones, accompanied by the downregulation of osteogenesis genes and upregulation of osteoclastogenesis genes of alveolar bones in ligatured Cyld KO mice. Taken together, our findings demonstrate that the deletion of CYLD in mice plays a vital role in the pathogenesis of periodontal bone loss and suggest that CYLD might exert an ameliorative effect on periodontal inflammatory responses.

Melatonin activates mitochondrial unfolded protein response to preserve osteogenic potential of senescent BMSCs via upregulating PDI-6.

Bone marrow stromal cells (BMSCs) possess the capability to differentiate into osteogenic or adipogenic lineages. With aging, BMSCs suffer from mitochondrial dysfunction and undergo senescence, favoring adipogenesis at the expense of osteoblastogenesis. It leads to decreased bone formation and contributes to senile osteoporosis (SOP). In the current study, RNA-seq analysis unveiled that senescent BMSCs from mice exhibited a significant suppression in the expression of the protein disulfide isomerase PDI-6, an important regulator of mitochondrial unfolded protein response (UPRmt) as well as maintenance of mitochondrial homeostasis. Overexpression of PDI-6 in senescent BMSCs partially rescued mitochondrial function and enhanced osteogenic differentiation. In contrast, osteoblastogenesis of BMSCs remarkably deteriorated under the condition of PDI-6 silencing. Furthermore, melatonin, an endocrine hormone, effectively enhanced PDI-6 expression and repaired injured mitochondria, and the effect of melatonin on PDI-6 expression was melatonin receptor dependent. We further identified that PDI-6 was a downstream effector of Wnt/ß-catenin pathway, as the inhibitor of Wnt3A/TCF signaling, Wnt-C59, inhibited PDI-6 expression. Potential ß-catenin-TCF/LEF binding sites on the promoter of PDI-6 gene were also validated by chromatin immunoprecipitation (ChIP) assay. Thus, our study suggests that PDI-6 is a pharmacological target of melatonin for the intervention of age-related osteoporosis via mitigating mitochondrial dysfunction in senescent BMSCs.

Effects of exercise training on neurological recovery, TGF-β1, HIF-1α, and Nogo-NgR signaling pathways after spinal cord injury in rats

Abstract Objective To evaluate the effects of exercise training on neurological recovery, Growth Transforming Factor-β1 (TGF-β1), Hypoxia Inducible Factor-1α (HIF-1α), and Nogo-NgR signaling pathways after spinal cord injury in rats. Methods Forty-eight male Sprague-Dawley rats were randomly divided into four groups: normal group, sham-operated group, model group, and training group. The rat spinal cord injury model was established using Allen's method, and the training group received exercise training on the 8th day postoperatively. The Basso, Beattie and Bresnahan (BBB) score, modified Tarlow score, and inclined plane test scores were compared in each group before injury and 1, 7, 14, 21 and 28 days after injury. Results The BBB score and modified Tarlow score of the model group and the training group were 0 at the first day after the injury, and gradually increased on the seventh day onwards (p < 0.05). The BBB score and modified Tarlow score of the training group were higher than those of the model group at the 14th, 21st and 28th day (p < 0.05). The angles of the inclined plate at multiple time points after injury were lower in the model group and the training group than in the normal group and the sham-operated group (p < 0.05); The angles of the inclined plate at the 14th, 21st and 28th day after injury were higher in the training group than in the model group (p < 0.05). Conclusion The mechanism of exercise training may be connected to the inhibition of the Nogo-NgR signaling pathway to promote neuronal growth.

Type-2 epithelial-mesenchymal transition in oral mucosal nonneoplastic diseases.

The oral mucosa is a membranous structure comprising epithelial and connective tissue that covers the oral cavity. The oral mucosa is the first immune barrier to protect the body against pathogens for systemic protection. It is frequently exposed to mechanical abrasion, chemical erosion, and pathogenic invasion, resulting in oral mucosal lesions, particularly inflammatory diseases. Epithelial-mesenchymal transition (EMT) is a crucial biological process in the pathogenesis of oral mucosal disorders, which are classified into three types (types 1, 2, and 3) based on their physiological consequences. Among these, type-2 EMT is crucial in wound repair, organ fibrosis, and tissue regeneration. It causes infectious and dis-infectious immunological diseases, such as oral lichen planus (OLP), oral leukoplakia, oral submucosal fibrosis, and other precancerous lesions. However, the mechanism and cognition between type-2 EMT and oral mucosal inflammatory disorders remain unknown. This review first provides a comprehensive evaluation of type-2 EMT in chronically inflammatory oral mucosal disorders. The aim is to lay a foundation for future research and suggest potential treatments.

NAP1L2 drives mesenchymal stem cell senescence and suppresses osteogenic differentiation.

Senescence of bone marrow mesenchymal stem cells (BMSCs) impairs stemness and osteogenic differentiation, but the key regulators for senescence and the related osteogenesis are not well defined. Herein, we screened the gene expression profiles of human BMSCs from young and old donors and identified that elevation of the nucleosome assembly protein 1-like 2 (NAP1L2) expression was correlated with BMSC senescence and impaired osteogenesis. Elevated NAP1L2 expression was observed in replicative cell senescence and induced cell senescence in vitro, and in age-related senescent human and mouse BMSCs in vivo, concomitant with significantly augmented chromatin accessibility detected by ATAC-seq. Loss- and gain-of-functions of NAP1L2 affected activation of NF-κB pathway, status of histone 3 lysine 14 acetylation (H3K14ac), and chromatin accessibility on osteogenic genes in BMSCs. Mechanistic studies revealed that NAP1L2, a histone chaperone, recruited SIRT1 to deacetylate H3K14ac on promoters of osteogenic genes such as Runx2, Sp7, and Bglap and suppressed the osteogenic differentiation of BMSCs. Importantly, molecular docking analysis showed a possible bond between NAP1L2 and an anti-aging reagent, the nicotinamide mononucleotide (NMN), and indeed, administration of NMN alleviated senescent phenotypes of BMSCs. In vivo and clinical evidence from aging mice and patients with senile osteoporosis also confirmed that elevation of NAP1L2 expression was associated with suppressed osteoblastogenesis. Taken together, our findings suggest that NAP1L2 is a regulator of both BMSC cell senescence and osteogenic differentiation, and provide a new theoretical basis for aging-related disease.

Interobserver and Intraobserver Reproducibility and Reliability of the Huashan Clinical Classification System for Hirayama Disease.

Purpose: The Huashan clinical classification system for Hirayama disease has recently been proposed and has been found useful for diagnosis and treatment. So far, however, there has been little in-depth evaluation of its reliability. Thus, this study aimed to assess the reproducibility and reliability of the system. Methods: Patients diagnosed with Hirayama disease between 2019 and 2020 were recruited. Seven spine surgeons from four different institutions, including an experienced group of three and an inexperienced group of four, were trained as observers of the Huashan clinical classification system for Hirayama disease, and these surgeons classified the recruited patients using the system. Then, 2 months later, they repeated the classification on the same patients in a different order. The interobserver and intraobserver agreement between the results was analyzed using percentage agreement and weighted kappa (κ) statistics. Results: A total of 60 patients were included in the analysis. For all the observers, experienced observers, and inexperienced observers, the agreement percentages were, respectively, 78.5% (κ = 0.76), 80.0% (κ = 0.78), and 78.9% (κ = 0.77), indicating substantial interobserver reproducibility. For distinguishing typical (Types I and II) and atypical (Type III) Hirayama disease among the different groups of observers, the percentage agreement ranged from 95.6 to 98.9% (κ = 0.74-0.92), indicating substantial to nearly perfect reproducibility. For suggesting conservative treatment (Types I and III) or surgery (Type II), the percentage agreement ranged from 93.3 to 96.4% (κ = 0.81-0.90), indicating nearly perfect reproducibility. As for intraobserver agreement, the percentage agreement ranged from 68.3 to 81.7% (κ = 0.65-0.79), indicating substantial reliability. Conclusion: The Huashan clinical classification system for Hirayama disease was easy to learn and apply in a clinical environment, showing excellent reproducibility and reliability. Therefore, it would be promising to apply and promote this system for the precise and individualized future treatment of Hirayama disease.

Epigenetic modifier trichostatin A enhanced osteogenic differentiation of mesenchymal stem cells by inhibiting NF-κB (p65) DNA binding and promoted periodontal repair in rats.

We wished to evaluate whether epigenetic modifiers have a beneficial effect on treating experimental periodontitis and mechanisms for regulating the cell fate of mesenchymal stem cells (MSCs) in inflammatory microenvironments. We isolated MSCs from healthy and inflamed gingival tissues to investigate whether trichostatin A (TSA) could improve osteogenic differentiation and resolve inflammation in vitro. The tissue regenerative potentials were evaluated when treated with a temperature-dependent, chitosan-scaffold-encapsulated TSA, in a rat model of periodontitis. After induction with the conditioned medium, TSA treatment increased the osteogenic differentiation potential of inflamed MSCs and healthy MSCs. In addition, interleukin-6 and interleukin-8 levels in supernatants were significantly decreased after TSA treatment. Moreover, TSA promoted osteogenic differentiation by inhibiting nuclear factor-κB (p65) DNA binding in MSCs. In rats with experimental periodontitis, 7 weeks after local injections of chitosan-scaffold-encapsulated TSA, histology and microcomputed tomography showed a significant increase in alveolar bone volume and less inflammatory infiltration compared with vehicle-treated rats. The concentrations of interferon-γ and interleukin-6 were significantly decreased in the gingival crevicular fluid after TSA treatment. This study demonstrated that TSA had anti-inflammatory properties and could promote periodontal tissue repair, which indicated that epigenetic modifiers hold promise as a potential therapeutic option for periodontal tissue repair.

Arf1-mediated lipid metabolism sustains cancer cells and its ablation induces anti-tumor immune responses in mice.

Cancer stem cells (CSCs) may be responsible for treatment resistance, tumor metastasis, and disease recurrence. Here we demonstrate that the Arf1-mediated lipid metabolism sustains cells enriched with CSCs and its ablation induces anti-tumor immune responses in mice. Notably, Arf1 ablation in cancer cells induces mitochondrial defects, endoplasmic-reticulum stress, and the release of damage-associated molecular patterns (DAMPs), which recruit and activate dendritic cells (DCs) at tumor sites. The activated immune system finally elicits antitumor immune surveillance by stimulating T-cell infiltration and activation. Furthermore, TCGA data analysis shows an inverse correlation between Arf1 expression and T-cell infiltration and activation along with patient survival in various human cancers. Our results reveal that Arf1-pathway knockdown not only kills CSCs but also elicits a tumor-specific immune response that converts dying CSCs into a therapeutic vaccine, leading to durable benefits.

Fabrication of pH-responsive TA-keratin bio-composited hydrogels encapsulated with photoluminescent GO quantum dots for improved bacterial inhibition and healing efficacy in wound care management: In vivo wound evaluations.

Wounds origins serious complications of lives of human beings which may leads to death. The important issue for the problem is infection during wound care management which delays wound healing process. These kinds of infections may be caused by the overuse or misuse of antibiotics, antidotes, usage of new drugs, not properly sterilized surgical instruments, not appropriate for pH level and imperfect wound dressing etc. during or after surgery. Hence in this report, antimicrobial action of pH responsive TA/KA composited hydrogel crosslinked with GO-QDs (TA/KA-GOQDs) using citric acid as cross-linker has been reported by demonstrating in-vitro and in-vivo studies for wound care management. The prepared samples of GOQDs, TA/KA hydrogel and TA/KA-GOQDs were characterized using FT-IR, XRD, SEM and TEM techniques. pH responsive hydrogel property of TA/KA was evaluated by swelling studies. In-vitro antibacterial studies was carried out by direct contact test method. Further, the prepared samples were tested in a wound healing model of rate with the wound of size 1.5 cm2 for in-vivo studies. After 16 days of treatment, the prepared samples for wound healing causes 100% wound areas closure. Histological observations were made by MT and HE staining process which proves keratinocytes proliferation by biocompatible and biocomposited TA/KA-GOQDs. The pH responsive TA/KA-GOQDs proved as efficient wound healing agent by faster keratinocytes proliferation within a compact period.

IGFBP2 upregulates ZEB1 expression and promotes hepatocellular carcinoma progression through NF-κB signaling pathway.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most lethal cancers owing to the high metastasis rate. The molecular mechanism underlying HCC progression remains unclear. AIMS: We aimed to explore the function and mechanism of action of insulin-like growth factor binding protein 2 (IGFBP2) in HCC. METHODS: Expression of IGFBP2 was evaluated with western blotting and reverse transcription polymerase chain reaction (RT-PCR). Loss- and gain-function assays were conducted to evaluate the effects of IGFBP2 on HCC cell proliferation, migration, and invasion. Signaling pathways were screened with a dual-fluorescein reporting system, and levels of epithelial and mesenchymal markers were measured after altering IGFBP2 expression. Cell fractionation analysis was conducted to evaluate the nuclear translocation of p65. RESULTS: IGFBP2 expression was upregulated in HCC tissues, predicted worse prognosis, and was associated with strong metastatic potentials. IGFBP2 depletion significantly inhibited HCC cell proliferation, migration, and invasion, whereas IGFBP2 overexpression showed reverse phenotypes. The underlying mechanism involved IGFBP2-mediated nuclear localization of p65, which activated nuclear factor kappa B (NF-κB) and zinc finger E-Box binding homeobox 1 (ZEB1) transcription via binding to the gene promoter. CONCLUSION: This study for the first time identifies IGFBP2 as a novel therapeutic target in HCC that activates the NF-κB-ZEB1 signaling axis and promotes HCC tumorigenesis.

Long non-coding RNA LINC01617 promotes proliferation and metastasis of esophageal cancer cells through AKT pathway.

OBJECTIVE: To investigate the clinical significance of long non-coding RNA LINC01617 in esophageal cancer and explore the effect of LINC01617 on the proliferation and metastasis of esophageal cancer cells. METHODS: Real time fluorescence PCR was used to detect the expression of LINC01617 in 142 cases of esophageal cancer and adjacent tissues. The relationship between the expression level of LINC01617 and the survival rate of esophageal cancer patients was analyzed. The function of LINC01617 was detected in esophageal cancer cell lines. The tumor growth ability test was carried out in the nude mice. RESULTS: We found that LINC01617 was overexpressed in esophageal cancer, and its expression was associated with poor prognosis of esophageal cancer. In vitro experiments confirmed that knockout of LINC01617 significantly inhibited the proliferation, migration and invasion of esophageal cancer cells. Moreover, knockout of LNC01617 can inhibit the growth of esophageal cancer in nude mice. The Akt pathway may be involved in the regulation of cell activity in esophageal cancer. CONCLUSIONS: LINC01617 may be involved in the occurrence and development of esophageal cancer, suggesting that LINC01617 can be used as a biomarker and potential therapeutic target for esophageal cancer.

MiR-93-5p up-regulation is involved in non-small cell lung cancer cells proliferation and migration and poor prognosis.

BACKGROUND/AIM: MicroRNA-93-5p (miR-93-5p) dysregulation has been reported in many types of human cancer. However, the collective effect of miR-93-5p in both lung adenocarcinoma and squamous cell carcinoma and the mechanism underlying miR-93-5p involvement in non-small cell lung cancer cells (NSCLC) is unknown. Herein, our purpose was to reveal the role and explain this mechanism, with the goal of contributing to the development of new diagnostic biomarkers and individualized therapeutic targets. MATERIALS AND METHODS: We examined miR-93-5p expression in NSCLC specimens (including lung adenocarcinoma and squamous cell carcinoma) by qPCR. The effects of miR-93-5p inhibitor on proliferation, migration, and invasion of NSCLC cells were determined by MTT assay, colony formation assays, apoptosis assay, cell cycle assay and transwell chamber assays, respectively. The molecular mechanisms underlying these effects were investigated via dual luciferase reporter assay and western blotting. RESULTS: MiR-93-5p expression levels were significantly correlated with NSCLC patients overall survival rate. Cell proliferation, migration, and invasion were significantly inhibited by miR-93-5p down-regulation. Dual luciferase reporter assay demonstrated that miR-93-5p directly bound with the 3'-untranslated region of the tumor suppressor gene PTEN and RB1. CONCLUSION: MiR-93-5p is up-regulated in NSCLC and plays an oncogenic role by inhibiting PTEN and RB1, suggesting miR-93-5p may be a novel prognostic indicator and a therapeutic target in NSCLC.

IGFBP2 enhances adipogenic differentiation potentials of mesenchymal stem cells from Wharton's jelly of the umbilical cord via JNK and Akt signaling pathways.

Mesenchymal stem cell (MSC)-mediated tissue engineering represents a promising strategy to address adipose tissue defects. MSCs derived from Wharton's jelly of the umbilical cord (WJCMSCs) may serve as an ideal source for adipose tissue engineering due to their abundance, safety profile, and accessibility. How to activate the directed differentiation potentials of WJCMSCs is the core point for their clinical applications. A thorough investigation of mechanisms involved in WJCMSC adipogenic differentiation is necessary to support their application in adipose tissue engineering and address shortcomings. Previous study showed, compared with periodontal ligament stem cells (PDLSCs), WJCMSCs had a weakened adipogenic differentiation potentials and lower expression of insulin-like growth factor binding protein 2 (IGFBP2). IGFBP2 may be involved in the adipogenesis of MSCs. Generally, IGFBP2 is involved in regulating biological activity of insulin-like growth factors, however, its functions in human MSCs are unclear. Here, we found IGFBP2 expression was upregulated upon adipogenic induction, and that IGFBP2 enhanced adipogenic differentiation of WJCMSCs and BMSCs. Moreover, IGFBP2 increased phosphorylation of c-Jun N-terminal kinase (p-JNK) and p-Akt, and activated JNK or Akt signaling significantly promoted adipogenic differentiation of MSCs. Furthermore, inhibitor-mediated blockage of either JNK or Akt signaling dramatically reduced IGFBP2-mediated adipogenic differentiation. And the JNK inhibitor, SP600125 markedly blocked IGFBP2-mediated Akt activation. Moreover, IGFBP2 was negatively regulated by BCOR, which inhibited adipogenic differentiation of WJCMSCs. Overall, our results reveal a new function of IGFBP2, providing a novel insight into the mechanism of adipogenic differentiation and identifying a potential target mediator for improving adipose tissue engineering based on WJCMSCs.

Treatment for Thoracic Ossification of Posterior Longitudinal Ligament with Posterior Circumferential Decompression.

OBJECTIVE: To report the results of the posterior approach for thoracic ossification of posterior longitudinal ligament (TOPLL) by using a special "L" osteotome. METHODS: The present study enrolled 16 consecutive patients (9 men and 7 women) between May 2009 and September 2013. All patients underwent a posterior circumferential decompression osteotomy and segmental instrumentation with interbody fusion. The mean age at surgery was 57.3 years (range, 37-68 years). Patients' data, clinical manifestation, blood loss, length of surgery, complications, visual analog scale (VAS), Japanese Orthopedic Association (JOA), and Frankel grading system before and after surgery were collected and evaluated, retrospectively. RESULTS: The average follow-up period was 30 ± 19 months (range, 12-50 months). All patients were successfully treated with posterior compression and segmental instrumentation with interbody fusion. The average operation time was 261.6 ± 51.3 min (range, 190-310 min). The mean blood loss was 980.3 ± 370.5 mL (range, 600-2100 mL). All patients had subjective improvement of motor power and gait. Average preoperative and postoperative JOA scores were 4.2 ± 1.7 and 7.8 ± 2.5 points, respectively. Differences in the overall JOA scores showed significant postoperative improvement. At the last follow-up, all patients improved either by one or two Frankel grades. There was a significant difference between preoperative VAS scores and those 3 months after surgery (P < 0.05). No significant difference was observed between the 3-month and 12-month results (P > 0.05). Cerebrospinal fluid (CSF) leakage occurred in 3 patients. Acute neurological deterioration was encountered postoperatively in 1 patient. CONCLUSION: Treatment with posterior transpedicular osteotomy and circumferential decompression was found to be safe, effective, reliable, and technically feasible, and keeping the thoracic cavity intact avoids many shortcomings of anterior surgery and results in a satisfactory spinal decompression.

IGFBP5 enhances osteogenic differentiation potential of periodontal ligament stem cells and Wharton's jelly umbilical cord stem cells, via the JNK and MEK/Erk signalling pathways.

OBJECTIVES: Mesenchymal stem cell (MSC)-mediated tissue regeneration represents a promising strategy for repair of tissue defects, but its molecular mechanisms remain unclear, restricting the use of MSCs. Our previous study indicated that insulin-like growth factor-binding protein 5 (IGFBP5) exerted a valuable effect on osteogenic differentiation of MSCs, but its molecular mechanisms underlying directed differentiation remained unclear. In this study, we have investigated the molecular role of IGFBP5 in regulating this osteogenic differentiation potential. MATERIALS AND METHODS: Periodontal ligament stem cells (PDLSCs) were isolated from periodontal ligament tissue. Wharton's jelly of umbilical cord stem cells (WJCMSCs) was obtained commercially. Lentiviral IGFBP5 shRNA was used to silence IGFBP5. Retroviruses expressing wild-type IGFBP5 were used to overexpress IGFBP5 in the WJCMSCs. Recombinant human IGFBP5 protein (rhIGFBP5) was used to treat PDLSCs for 24 h. Western blot analysis was used to detect the MAPK signalling pathway, and alkaline phosphatase (ALP) activity, Alizarin Red staining and quantitative calcium analysis were used to study osteogenic differentiation potentials. RESULTS: Overexpression of IGFBP5 or rhIGFBP5 increased expression levels of phosphorylated c-Jun N-terminal kinase (p-JNK), phosphorylated mitogen-activated protein kinase 1 and 2 (p-MEK1/2) and phosphorylated extracellular regulated protein kinases (p-Erk1/2) in both WJCMSCs and PDLSCs. Consistently, silenced IGFBP5 was found to effectively inhibit expression of p-JNK, p-Erk1/2 and p-MEK1/2 in PDLSCs and WJCMSCs. Furthermore, inhibition of JNK by its inhibitor, SP600125, or MEK/Erk signalling by its inhibitor, PD98059, dramatically blocked IGFBP5-enhanced ALP activity and in vitro mineralization in both PDLSCs and WJCMSCs. CONCLUSIONS: Our results demonstrated that IGFBP5 promoted osteogenic differentiation potentials of PDLSCs and WJCMSCs via the JNK and MEK/Erk signalling pathways.