USP1/UAF1-Stabilized METTL3 Promotes Reactive Astrogliosis and Improves Functional Recovery after Spinal Cord Injury through m6A Modification of YAP1 mRNA.

RNA N6-methyladenosine (m6A) modification is involved in diverse biological processes. However, its role in spinal cord injury (SCI) is poorly understood. The m6A level increases in injured spinal cord, and METTL3, which is the core subunit of methyltransferase complex, is upregulated in reactive astrocytes and further stabilized by the USP1/UAF1 complex after SCI. The USP1/UAF1 complex specifically binds to and subsequently removes K48-linked ubiquitination of the METTL3 protein to maintain its stability after SCI. Moreover, conditional knockout of astrocytic METTL3 in both sexes of mice significantly suppressed reactive astrogliosis after SCI, thus resulting in widespread infiltration of inflammatory cells, aggravated neuronal loss, hampered axonal regeneration, and impaired functional recovery. Mechanistically, the YAP1 transcript was identified as a potential target of METTL3 in astrocytes. METTL3 could selectively methylate the 3'-UTR region of the YAP1 transcript, which subsequently maintains its stability in an IGF2BP2-dependent manner. In vivo, YAP1 overexpression by adeno-associated virus injection remarkably contributed to reactive astrogliosis and partly reversed the detrimental effects of METTL3 knockout on functional recovery after SCI. Furthermore, we found that the methyltransferase activity of METTL3 plays an essential role in reactive astrogliosis and motor repair, whereas METTL3 mutant without methyltransferase function failed to promote functional recovery after SCI. Our study reveals the previously unreported role of METTL3-mediated m6A modification in SCI and might provide a potential therapy for SCI.SIGNIFICANCE STATEMENT Spinal cord injury is a devastating trauma of the CNS involving motor and sensory impairments. However, epigenetic modification in spinal cord injury is still unclear. Here, we propose an m6A regulation effect of astrocytic METTL3 following spinal cord injury, and we further characterize its underlying mechanism, which might provide promising strategies for spinal cord injury treatment.

Necroptosis pathway emerged as potential diagnosis markers in spinal cord injury.

The present research focused on identifying necroptosis-related differentially expressed genes (NRDEGs) in spinal cord injury (SCI) to highlight potential therapeutic and prognostic target genes in clinical SCI. Three SCI-related datasets were downloaded, including GSE151371, GSE5296 and GSE47681. MSigDB and KEGG datasets were searched for necroptosis-related genes (NRGs). Differentially expressed genes (DEGs) and NRGs were intersected to obtain NRDEGs. The MCC algorithm was employed to select the first 10 genes as hub genes. A protein-protein interaction (PPI) network related to NRDEGs was developed utilizing STRING. Several databases were searched to predict interactions between hub genes and miRNAs, transcription factors, potential drugs, and small molecules. Immunoassays were performed to identify DEGs using CIBERSORTx. Additionally, qRT-PCR was carried out to verify NRDEGs in an animal model of SCI. Combined analysis of all datasets identified 15 co-expressed DEGs and NRGs. GO and KEGG pathway analyses highlighted DEGs mostly belonged to pathways associated with necroptosis and apoptosis. Hub gene expression analysis showed high accuracy in SCI diagnosis was associated with the expression of CHMP7 and FADD. A total of two hub genes, i.e. CHMP7, FADD, were considered potential targets for SCI therapy.

Necroptosis-related LncRNAs in skin cutaneous melanoma: evaluating prognosis, predicting immunity, and guiding therapy.

BACKGROUND: An increasing amount of research has speculated that necroptosis could be a therapeutic strategy for treating cancer. However, understanding the prognostic value of the necroptosis-related long non-coding RNAs (NRLs) in skin cutaneous melanoma (SKCM, hereafter referred to as melanoma) remains poor and needs to be developed. Our research aims to construct a model based on NRLs for the prognosis of patients with melanoma. METHODS: We obtained the RNA-seq and clinical data from The Cancer Genome Atlas (TCGA) database and retrieved 86 necroptosis-related genes from the GeneCards database. The lncRNAs associated with necroptosis were identified via the Pearson correlation coefficient, and the prognostic model of melanoma was constructed using LASSO regression. Next, we employed multiple approaches to verify the accuracy of the model. Melanoma patients were categorized into two groups (high-risk and low-risk) according to the results of LASSO regression. The relationships between the risk score and survival status, clinicopathological correlation, functional enrichment, immune infiltration, somatic mutation, and drug sensitivity were further investigated. Finally, the functions of AL162457.2 on melanoma proliferation, invasion, and migration were validated by in vitro experiments. RESULTS: The prognostic model consists of seven NRLs (EBLN3P, AC093010.2, LINC01871, IRF2-DT, AL162457.2, AC242842.1, HLA-DQB1-AS1) and shows high diagnostic efficiency. Overall survival in the high-risk group was significantly lower than in the low-risk group, and risk scores could be used to predict melanoma survival outcomes independently. Significant differences were evident between risk groups regarding the expression of immune checkpoint genes, immune infiltration, immunotherapeutic response and drug sensitivity analysis. A series of functional cell assays indicated that silencing AL162457.2 significantly inhibited cell proliferation, invasion, and migration in A375 cells. CONCLUSION: Our prognostic model can independently predict the survival of melanoma patients while providing a basis for the subsequent investigation of necroptosis in melanoma and a new perspective on the clinical diagnosis and treatment of melanoma.

Transplantation of A2 type astrocytes promotes neural repair and remyelination after spinal cord injury.

BACKGROUND: Limited progress in terms of an effective treatment for spinal cord injury (SCI) emphasizes the urgent need for novel therapies. As a vital central nervous system component, the resident astrocytes play crucial roles in regulating recovery after SCI. In this study, recovery after SCI was compared following the transplantation of either A1 or A2 astrocytes. A1 astrocytes are harmful as they upregulate the neurotoxic classical complement cascade genes. Conversely, A2 astrocytes are characterized as neuroprotective as they upregulate the production of many neurotrophic factors. METHODS: We used different supernatant obtained from microglia stimulated with lipopolysaccharide or interleukin-4 to generate A1 and A2 astrocytes. We detected the influence of astrocytes on neurons by co-culturing A1 and A2 astrocytes with neurons. We transplanted astrocytes into the lesion site of the spinal cord and assessed lesion progression, neural restoration, glia formation and locomotor recovery. RESULTS: Astrocytes were polarized into A1 and A2 phenotypes following culture in the supernatant obtained from microglia stimulated with lipopolysaccharide or interleukin-4, respectively. Furthermore, co-culturing A2 astrocytes with neurons significantly suppressed glutamate-induced neuronal apoptosis and promoted the degree of neuron arborization. Transplantation of these A2 astrocytes into the lesion site of the spinal cord of mice significantly improved motor function recovery, preserved spared supraspinal pathways, decreased glia scar deposition, and increased neurofilament formation at the site of injury compared to the transplantation of A1 astrocytes. Additionally, enhanced A2 astrocytes with potentially beneficial A2-like genes were also detected in the A2 group. Moreover, luxol fast blue staining and electron microscopy indicated increased preservation of myelin with organized structure after transplantation of A2 astrocytes than of A1 astrocytes. CONCLUSIONS: A2 astrocyte transplantation could be a promising potential therapy for SCI. Video abstract.

Epinephrine Stimulates Mycobacterium tuberculosis Growth and Biofilm Formation.

The human stress hormones catecholamines play a critical role in communication between human microbiota and their hosts and influence the outcomes of bacterial infections. However, it is unclear how M. tuberculosis senses and responds to certain types of human stress hormones. In this study, we screened several human catecholamine stress hormones (epinephrine, norepinephrine, and dopamine) for their effects on Mycobacterium growth. Our results showed that epinephrine significantly stimulated the growth of M. tuberculosis in the serum-based medium as well as macrophages. In silico analysis and molecular docking suggested that the extra-cytoplasmic domain of the MprB might be the putative adrenergic sensor. Furthermore, we showed that epinephrine significantly enhances M. tuberculosis biofilm formation, which has distinct texture composition, antibiotic resistance, and stress tolerance. Together, our data revealed the effect and mechanism of epinephrine on the growth and biofilm formation of M. tuberculosis, which contributes to the understanding of the environmental perception and antibiotic resistance of M. tuberculosis and provides important clues for the understanding of bacterial pathogenesis and the development of novel antibacterial therapeutics.

OASs in Defense of Mycobacterial Infection: Angels or Demons?

The interaction between pattern-recognition receptors (PRRs) and pathogen- associated molecular patterns (PAMPs) induces type I interferon (IFN) responses. IFNs stimulates hundreds of genes to exert its biological effects. OASs are the members of IFN-stimulate genes (ISGs). Among them, OAS1 activates RNase L to cleave RNA viruses genome, OAS2 activates downstream immune signaling pathways of IFNs, OAS3 induces RNase L to cut the genome of RNA virus and activate IFN I response to enhance the immune effect, and OASL inhibits the survival of RNA viruses by activating RIG-I signaling pathway but promotes the reproduction of DNA viruses by inhibiting the cGAS signaling pathway. However, the role of OASs in mycobacterial infection remains incomprehensible. In this review, we summarized the latest literature regarding the roles of OASs in mycobacterial infection.

A comparison of the bilateral decompression via unilateral approach versus conventional approach transforaminal lumbar interbody fusion for the treatment of lumbar degenerative disc disease in the elderly.

BACKGROUND: Bilateral decompression via unilateral approach (BDUA) is an effective surgical approach for treating lumbar degenerative diseases. However, no studies of prognosis, especially the recovery of the soft tissue, have reported using BDUA in an elderly population. The aims of these research were to investigate the early efficacy of the bilateral decompression via unilateral approach versus conventional approach transforaminal lumbar interbody fusion (TLIF) for the treatment of lumbar degenerative disc disease in the patients over 65 years of age, especially in the perioperative factors and the recovery of the soft tissue. METHODS: The clinical data from 61 aging patients with lumbar degenerative disease who received surgical treatment were retrospectively analyzed. 31 cases who received the lumbar interbody fusion surgery with bilateral decompression via unilateral approach (BDUA) were compared with 30 cases who received conventional approach transforaminal lumbar interbody fusion. The radiographic parameters were measured using X-ray including lumbar lordosis angle and fusion rate. Japanese Orthopedic Association (JOA), Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) scores were used to evaluate the clinical outcomes at different time points. Fatty degeneration ratio and area of muscle/vertebral body were used to detect recovery of soft tissue. RESULTS: The BDUA approach group was found to have significantly less intraoperative blood loss(p < 0.05) and postoperative drainage(p < 0.05) compared to conventional approach transforaminal lumbar interbody fusion group. Symptoms of spinal canal stenosis and nerve compression were significantly relieved postoperatively, as compared with the preoperative state. However, the opposite side had a lower rate of fatty degeneration (9.42 ± 3.17%) comparing to decompression side (11.68 ± 3.08%) (P < 0.05) six months after surgery in the BDUA group. While there were no significant differences (P > 0.05) in two sides of conventional transforaminal lumbar interbody fusion approach group six months after surgery. CONCLUSIONS: Bilateral decompression via unilateral approach (BDUA) is able to reduce the intraoperative and postoperative body fluid loss in the elderly. The opposite side of decompression in BDUA shows less fatty degeneration in 6 months, which indicates better recovery of the soft tissue of the aging patients.

Excess administration of miR-340-5p ameliorates spinal cord injury-induced neuroinflammation and apoptosis by modulating the P38-MAPK signaling pathway.

Spinal cord injury (SCI) is a destructive polyneuropathy that can result in loss of sensorimotor function and sphincter dysfunction, and even death in critical situations. MicroRNAs (miRs) are a series of non-coding RNA molecules that are involved in transcriptional regulation. Previous studies have demonstrated that modulation of multiple miRs is involved in neurological recovery after SCI. However, the functions of miR-340-5p in SCI remain uncertain. Therefore, we probed the therapeutic effect and mechanism of miR-340-5p in microglia in vitro and in vivo in SCI rats. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were employed to examine the alterations in miR-340-5p and P38 levels in SCI rats. miR-340-5p targets in microglia were ascertained using luciferase reporter assays, immunofluorescence analyses, and western blotting. We also established an SCI model and administered miR-340-5p. The effects of miR-340-5p on the amelioration of inflammation, oxidative stress, and apoptosis following SCI were assessed using immunofluorescence, immunohistochemistry, and histological analyses. Finally, locomotor function recovery was determined using the Basso, Beattie, Bresnahan rating scale. In our study, the expression profiles and luciferase assay results clarified that P38 was a target of miR-340-5p, which was associated with activation of the P38-MAPK signaling pathway. Elevation of miR-340-5p decreased P38 expression, subsequently inhibiting the inflammatory reaction. SCI-induced secondary neuroinflammation was relieved under miR-340-5p treatment. Moreover, by controlling neuroinflammation, the increased levels of miR-340-5p might counter oxidative stress and reduce the degree of apoptosis. We also observed decreasing gliosis and glial scar formation and increasing neurotrophin expression at the chronic stage of SCI. Together, these potential effects of miR-340-5p treatment ultimately improved locomotor function recovery in SCI rats.

MiR-214 Attenuates Osteogenic Differentiation of Mesenchymal Stem Cells via Targeting FGFR1.

BACKGROUND/AIMS: Postmenopausal osteoporosis is closely associated with reduction in the differentiation of mesenchymal stem cells (MSCs) into osteoblasts. Previous studies have demonstrated that miR-214 plays an important role in the genesis and development of postmenopausal osteoporosis. Here, we performed this study to investigate the potential mechanism by which miR-214 regulates osteoblast differentiation of MSCs. METHODS: First, we explored the expression of miR-214 in MSCs of osteoporotic mice. Next, we examined the change of miR-214 during osteoblast differentiation of MSCs. Then, MSCs were infected with lentiviral vectors expressing miR-214 or miR-214 sponge to investigate the effect of miR-214 on osteoblast differentiation of MSCs. Further, bioinformatics analysis and luciferase reporter assay were performed to identify and validate the target gene of miR-214. RESULTS: MiR-214 was up-regulated in MSCs of osteoporotic mice and down-regulated during osteoblast differentiation of MSCs. Furthermore, overexpression of miR-214 inhibited osteoblast differentiation of MSCs in vitro, whereas inhibition of miR-214 function promoted this process, evidenced by increased expression of osteoblast-specific genes, alkaline phosphatase (ALP) activity, and matrix mineralization. Bioinformatics, Western blot analysis and luciferase reporter assay demonstrated that FGFR1 is a direct target of miR-214. CONCLUSIONS: MiR-214 attenuates osteogenesis by inhibiting the FGFR1/FGF signaling pathway. Our findings suggest that targeting miR-214 promises to be a potential therapy in treatment of postmenopausal osteoporosis.

ER Stress via CHOP Pathway is Involved in FK506-Induced Apoptosis in Rat Fibroblasts.

BACKGROUND/AIMS: Hypertrophic scars (HS) formation results from reduced apoptosis and increased proliferation of fibroblasts. Therefore, apoptosis of fibroblasts is a key target for the development of novel therapeutic strategies for HS. Previous reports demonstrated that FK506 could attenuate scar formation in vivo and FK506 could also induce endoplasmic reticulum stress (ER stress). However, the effects of FK506 on ER stress-mediated apoptosis in fibroblasts remain unclear. METHODS: Rat skin fibroblasts were used in the study. Cell viability was examined using cell counting Kit-8. Apoptosis was detected by Annexin V/Propidium Iodide Double Staining. Gene silencing was performed using Small Interfering RNAs (siRNAs) or via lentiviral infection. The expression of apoptosis-related proteins was determined via Western blot. Interaction between proteins was explored by co-immunoprecipitation. RESULTS: FK506 significantly reduced cell viability and induced apoptosis in fibroblasts. Interestingly, ER stress was also activated after FK506 treatment. We further demonstrated that FK506-induced apoptosis was mediated by ER stress via activating CHOP, evidenced by decreased apoptosis after inhibition of ER stress using TUDCA or silencing expression of CHOP. Furthermore, Co-immunoprecipitation results indicated that treatment of FK506 induced disassociation of FKBP12.6 from RyR2 and its translocation from ER membrane to cytosol, consequently promoting ER stress-mediated apoptosis. CONCLUSION: FK506-induced fibroblasts apoptosis was mediated by ER stress via CHOP signaling pathway.

Taurine Reduced Epidural Fibrosis in Rat Models after Laminectomy via Downregulating EGR1.

BACKGROUND/AIMS: Epidural fibrosis, a common complication after laminectomy, has been demonstrated to be closely associated with poor surgical outcomes. Previous studies showed that taurine had remarkable anti-fibrotic effects on lung and liver fibrosis. We performed this study to investigate the effects of taurine in rat models of epidural fibrosis after laminectomy and to explore the potential molecular mechanism. METHODS: Laminectomy was performed on each rat to establish epidural fibrosis model. After taurine treatment, Masson's trichrome and immunohistochemistry staining were used to examine epidural fibrosis. Cell viability was determined using the Cell Counting Kit-8 assay. Annexin V/Propidium Iodide double staining was performed to detect fibroblasts apoptosis. Microarray was adopted to identify significantly changed mRNAs. mRNA expression was measured by qRT-PCR. Lentivirus infection was performed to establish stable knockdown and overexpression cell lines. The expression of fibrosis-related proteins was determined via Western blot. RESULTS: Taurine treatment markedly reduced laminectomy-induced epidural fibrosis in rat models. However, this effect of taurine was independent on TGF-ß/Smad pathway, evidenced by no change in the expression of TGF-ß and its receptors. Besides, taurine had almost no effect on cell apoptosis. Interestingly, taurine treatment significantly decreased expression of EGR1 (Early growth response protein 1), an enhancer of fibrosis, both in vivo and in vitro. Furthermore, overexpression of EGR1 increased activation of fibroblasts, while EGR1 knockdown achieved an opposite effect, indicating that EGR1 plays a key role in the inhibitory effect of taurine on TGF-ß-induced fibrosis. CONCLUSIONS: Reduced epidural fibrosis in vivo and decreased activation of fibroblasts in vitro after taurine treatment was mediated by EGR1. Taurine promises to be a potential prevention for epidural fibrosis after laminectomy.

Comparison of perpendicular to the coronal plane versus medial inclination for atlas pedicle screw insertion: an anatomic and radiological study in human cadavers.

PURPOSE: To ascertain the anatomic and radiological parameters of the atlas (C1) pedicle and to explore a preferable method of C1 pedicle screw insertion. METHODS: Thirty-four conserved human cadaveric cervical spines (20 males, 14 females) underwent computed tomography (CT) scanning. Trajectories P (perpendicular to the coronal plane) and I (with medial inclination) were designed for each C1 pedicle on CT images. External pedicle wall width, medullary cavity width, transverse angle, and optimal entry point along each trajectory were measured. Cortical screws of 3.5 mm in diameter were inserted into C1 pedicles along trajectory P and I, respectively, and wall perforation was assessed (post-operative CT scanning). RESULTS: The external pedicle wall width and medullary cavity width along trajectory I were significantly wider than trajectory P (P < 0.01). Although external pedicle wall widths were all greater than 3.5 mm, medullary cavity width <3.5 mm was found in 16.1 % pedicles along trajectory P and only 2.9 % along trajectory I. Transverse angle was 21.8° along trajectory I and 0° along trajectory P. Optimal entry point of trajectory I was 4.1 mm lateral from that of trajectory P. The lateral wall perforation rate was significantly lower along trajectory I than trajectory P (P < 0.05). CONCLUSIONS: C1 pedicle screw trajectory with medial inclination and more lateral entry points yielded wider medullary cavity width than that perpendicular to the coronal plane, and might minimize lateral wall perforation.

Schwann Cells Transplantation Improves Locomotor Recovery in Rat Models with Spinal Cord Injury: a Systematic Review and Meta-Analysis.

BACKGROUND/AIMS: Schwann cells (SCs) which were demonstrated to be responsible for axonal myelination and ensheathing are widely studied and commonly used for cell transplantation to treat spinal cord injury (SCI). We performed this meta-analysis to summarize the effects of SCs versus controls for locomotor recovery in rat models of traumatic SCI. METHODS: Studies of the BBB scores after transplantation of SCs were searched out from Pubmed, Cochrane Library Medline databases and analyzed by Review Manager 5.2.5. RESULTS: Thirteen randomized controlled animal trials were selected with 283 rats enrolled. The studies were divided to different subgroups by different models of SCI, different cell doses for transplantation, different sources of SCs and different transplantation ways. The pooled results of this meta-analysis suggested that SCs transplantation cannot significantly improve the locomotor recovery at a short time after intervention (1 week after transplantation) in both impacted and hemi-sected SCI models. However, at a longer time after intervention (3, 5-7 and over 8 weeks after transplantation), significant improvement of BBB score emerged in SCs groups compared with control groups. Subgroup analyses revealed that SCs transplantation can significantly promote locomotor recovery regardless of in high or low doses of cells, from different sources (isolated from sciatic nerves or differentiated from bone marrow stromal cells(BMSCs)) and with or without scaffolding. CONCLUSION: SCs seem to demonstrate substantial beneficial effects on locomotor recovery in a widely-used animal models of SCI.

Mitomycin C induces apoptosis in rheumatoid arthritis fibroblast-like synoviocytes via a mitochondrial-mediated pathway.

BACKGROUND/AIMS: Rheumatoid arthritis (RA) is a systemic chronic inflammatory disease characterised by prominent synoviocyte hyperplasia and a potential imbalance between the growth and death of fibroblast-like synoviocytes (FLS). Mitomycin C (MMC) has previously been demonstrated to inhibit fibroblast proliferation and to induce fibroblast apoptosis. However, the effects of MMC on the proliferation and apoptosis of human RA FLS and the potential mechanisms underlying its effects remain unknown. METHODS: Cell viability was determined using the Cell Counting Kit-8 assay. Apoptotic cell death was analysed via Annexin V-FITC/PI double staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling. The production of intracellular reactive oxygen species (ROS) was assessed via flow cytometry, and the changes in mitochondrial membrane potential (ΔΨm) were visualized based on JC-1 staining via fluorescence microscopy. The expression of apoptosis-related proteins was determined via Western blot. RESULTS: Treatment with MMC significantly reduced cell viability and induced apoptosis in RA FLS. Furthermore, MMC exposure was found to stimulate the production of ROS and to disrupt the ΔΨm compared to the control treatment. Moreover, MMC increased the release of mitochondrial cytochrome c, the ratio of Bax/Bcl-2, the activation of caspase-9 and caspase-3, and the subsequent cleavage of poly(ADP-ribose) polymerase. CONCLUSION: Our findings suggest that MMC inhibits cell proliferation and induces apoptosis in RA FLS, and the mechanism underlying this MMC-induced apoptosis may involve a mitochondrial signalling pathway.

K6PC-5, a novel sphingosine kinase 1 (SphK1) activator, alleviates dexamethasone-induced damages to osteoblasts through activating SphK1-Akt signaling.

Long-term glucocorticoid usage is a common cause of non-traumatic femoral head osteonecrosis. Glucocorticoids (i.e. dexamethasone (Dex)) could directly induce damages to osteoblasts. In the current study, we investigated the potential activity of K6PC-5 [N-(1,3-dihydroxyisopropyl)-2-hexyl-3-oxo-decanamide], a novel sphingosine kinase 1 (SphK1) activator, against this process. Our data revealed that both osteoblastic-like MC3T3-E1 cells and primary murine osteoblasts were responsible to K6PC-5. K6PC-5 activated SphK1, increased sphingosine-1-phosphate (S1P) production and induced Akt phosphorylation in cultured osteoblasts. Functionally, K6PC-5 protected osteoblasts from Dex-induced apoptosis and necrosis. Such signaling and functional effects by K6PC-5 were prevented by the SphK1 inhibitor N,N-dimethylsphingosine (DMS), and by SphK1-siRNAs. On the other hand, exogenously-added S1P activated Akt and reduced Dex-induced osteoblast damages. LY294002 and MK-2206, two established Akt inhibitors, alleviated K6PC-5- or S1P-mediated osteoblast protection against Dex. Together, our results suggest that K6PC-5 alleviates Dex-induced osteoblast injuries through activating SphK1-Akt signaling. K6PC-5 might be further investigated in animal or clinical studies for its anti-glucocorticoids-associated osteonecrosis potential.

An MRI-based feasibility study of unilateral percutaneous vertebroplasty.

BACKGROUND: Percutaneous vertebroplasty (PVP) has been demonstrated to be effective in the treatment of osteoporotic fracture. The bilateral pedicular approach is the most frequently used method. However, unilateral PVP is becoming increasingly more attractive for surgeons because of its numerous benefits, including lower radiation exposure, less tissue injury, and less bone cement leakage. The purpose of this study was to investigate the anatomical feasibility of unilateral PVP by exploring the differences in the puncture success rate of the unilateral pedicular approach among different lumbar segments, between men and women, and between the left and right sides. METHODS: Punctures were simulated on magnetic resonance imaging scans of 200 patients (100 men, 100 women) at a maximum angle via a pedicular approach. The distance between the entry point and the midline of the vertebral body, the maximum puncture angle, the puncture success value, and the puncture success rate were measured and compared among different lumbar levels, between the two sexes, and between the left and right sides. RESULTS: The maximum puncture distance between the entry point and the midline gradually increased from L1 to L5, and the maximum puncture angle showed the same tendency from L1 to L5. The puncture success values for L3 and L4 were higher than those for the other lumbar levels (L1, 31.53 ± 34.45; L2, 42.15 ± 28.06; L3, 56.21 ± 18.30; L4, 56.20 ± 12.93; and L5, 48.01 ± 6.88). The puncture success rates varied from 69.5 to 98.0 % among the different lumbar levels; L3 and L4 were the two highest (L3, 95.5 %; L4, 98.0 %). There were significant differences in these measurements between men and women and between the left and right sides. CONCLUSIONS: PVP with the unilateral puncture approach appears more likely to succeed at L3 to L5 than at L1 and L2. The unilateral approach might be more suitable for men than women at levels other than L5. Additionally, the left pedicular approach might be optimal for unilateral PVP procedures.

The diameters and number of nerve fibers in spinal nerve roots.

OBJECTIVE: To investigate the anatomical and histological features of spinal nerve roots and provide base data for neuroanastomosis therapy for paraplegia. METHODS: Spinal nerve roots from C1 to S5 were exposed on six adult cadavers. The diameter and the number of nerve fibers of each nerve root were measured, respectively, with a caliper and image analysis software. RESULTS: As for ventral roots, the diameter of C5 (2.50 ± 0.55 mm) was the largest in cervical segments. In thoracic and lumbosacral segments, the diameter gradually increased from T11 to S1 and then decreased from S1 to S5 except L3. S1 (1.43 ± 0.16 mm) was the thickest root and S5 (0.14 ± 0.02 mm) was the thinnest one. As for dorsal roots, the diameter of C7 (4.61 ± 0.87 mm) was the largest in cervical segments. From T11 to S1, the diameter increased and then decreased gradually from S1 to S5. The diameter of dorsal roots from T1 to S5 was largest at S1 (2.95 ± 0.57 mm) and smallest at S5 (0.27 ± 0.13 mm), respectively. C7 (8467 ± 1019), T12 (6538 ± 892), L3 (9169 ± 1160), and S1 (8253 ± 1419) ventral roots contained the most nerve fibers in cervical, thoracic, lumbar, and sacral segments, respectively. Similarly, C7 (39 653 ± 8458), T1 (26 507 ± 7617), L5 (34 455 ± 2740), and S1 (41 543 ± 3036) dorsal roots, respectively, contained the most nerve fibers in their corresponding segments. CONCLUSION: The findings in the current study provided the imperative data and may be valuable for spinal nerve root microanastomosis surgery in the paraplegic patients.

Effect of ultrasonic surface impact on the microstructural characterization and mechanical properties of 316L austenitic stainless steel.

In the present study, effect of ultrasonic impact treatment (UIT) on the microstructural characterization and mechanical properties of 316L stainless steel (hereinafter referred to as 316L) was investigated experimentally. The fatigue fracture mechanism of 316L before and after UIT was revealed. The experimental results indicated that the martensitic grain size induced at the impact edge was about 2.00 Å. The surface modified 316L formed a gradient nanostructure and induced a martensitic phase transformation. The hardness of the surface layer of the modified 316L was twice the hardness of its matrix. The tensile strengths of 316L before and after UIT were 576 MPa and 703 MPa, respectively. The stretching stripes of 316L were more disordered after UIT. The fatigue strengths of 316L before and after UIT were 267 MPa and 327 MPa, respectively. The fatigue cracking of 316L started from the austenite grain boundaries. The fatigue fracture surface was relatively rough. The fatigue crack sources of the modified 316L came from internal inclusions. The inclusions were oxides dominated by SiO2. As the stress range increased, the crack initiation site migrated to the interior and the fatigue fracture surface became flatter.

Osteoclast-derived exosomes influence osteoblast differentiation in osteoporosis progression via the lncRNA AW011738/ miR-24-2-5p/ TREM1 axis.

AIMS: To investigate the molecular mechanism of osteoclast-derived exosomes in osteoporosis. MAIN METHODS: RANKL induced osteoclast model was screened for significantly differentially expressed lncRNAs and mRNAs by whole RNA sequencing. Exosomes were characterized using electron microscopy, western blotting and nanosight. Overexpression or knockdown of AW011738 was performed to explore its function. The degree of osteoporosis in an osteoporosis model was assessed by mirco-CT. The osteoclast model, osteoblast differentiation ability and the molecular mechanism of lncRNA AW011738/miR-24-2-5p/TREM1 axis in osteoporosis were assessed by dual luciferase reporter gene assay, Western blotting (WB), immunofluorescence and ALP staining. Bioinformatics was used to predict interactions of key osteoporosis-related genes with miRNAs, transcription factors, and potential drugs after upregulation of AW011738. To predict the protein-protein interaction (PPI) network associated with key genes, GO and KEGG analyses were performed on the key genes. The ssGSVA was used to predict changes in the immune microenvironment. KEY FINDINGS: Osteoclast-derived exosomes containing lncRNA AW011738 decreased the osteogenesis-related markers and accelerated bone loss in OVX mice. Osteoclast (si-AW011738)-derived exosomes showed a significant increase in biomarkers of osteoblast differentiation in vitro compared to the si-NC group. As analyzed by mirco-CT, tail vein injected si-AW011738 OVX mice were less osteoporotic than the control group. AW011738 inhibited osteoblast differentiation by regulating TREM1 expression through microRNA. Meanwhile, overexpression of miR-24-2-5p inhibited TREM1 expression to promote osteoblast differentiation. SIGNIFICANCE: Osteoclast-derived exosomes containing lncRNA AW011738 inhibit osteogenesis in MC3T3-E1 cells through the lncRNA AW011738/miR-24-2-5p/TREM1 axis and exacerbate osteoporosis in OVX mice.

Treadmill exercise improves cerebral ischemia injury by regulating microglia polarization via downregulation of MMP12.

BACKGROUD: Exercise training is the main strategy for stroke rehabilitation, and it has shown that shifting microglia toward M2 phenotype is beneficial for the recovery of neurological function after stroke. The mechanisms governing exercise training and inflammatory response after cerebral ischemia remain largely unexplored. Herein, the aim of this study was to investigate the role of exercise training in immune response after cerebral ischemia. METHODS: The transient middle cerebral artery occlusion (MCAO) rat model and primary microglia under oxygen-glucose deprivation/reoxygenation (OGD/R) conditions were used to mimic the ischemic stroke in vivo and in vitro respectively. Treadmill exercise with gradually increased intensity was initiated the second day after MCAO for a maximum of 14 days. The beam balance test, forelimb placement test, cornering test, modified adhesive removal test were used to assess the behavioral recovery. The right peri-infarct cortex was taken from 3 rats per group for RNA sequencing (RNA-seq) analysis. Real-time PCR, western blot, immunofluorescence, and phagocytosis assay was performed after MCAO and/or OGD/R. RESULTS: Treadmill exercise could significantly improve behavioral outcomes and reduce the infarct volumes. In addition, treadmill exercise switched microglia polarization toward M2 phenotype (Iba+/CD206+) in the peri-infarct cortex, and significantly increased the levels of anti-inflammatory factors (TGF-ß, IL10, Arg-1, CD206) and decreased a pool of pro-inflammatory factors (IL-1ß, IL-6, TNF-α, iNOS, CD68) in the peri-infarct areas. RNA-seq analysis and further studies demonstrated that exercise training could significantly reduce the expression of MMP12. Through further immunofluorescence co-labeling analysis, we found that treadmill exercise predominantly reduced the expression of MMP-12 in microglia but not in neuron after MCAO. In primary microglia after OGD/R, MMP12 inhibition switched microglia polarization toward to M2 phenotype, increased the expression of M2 markers, and enhanced its phagocytic capacities. CONCLUSIONS: Our data demonstrate that treadmill exercise could improve the inflammatory microenvironment in the brain after ischemic stroke, which may be caused by inhibition of MMP12 expression. MMP12 suppression in primary microglia could remodel microglia immune functions. In summary, this study may provide novel insights into the immune mechanism of exercise training for stroke and suggests potential targets for therapeutic approaches.