Modified pedicle screw-rod fixation versus open reduction plate fixation for the management of pubic symphysis diastasis: A retrospective study.

Objective: Surgical intervention and fixation is the recognized measurement to treat pubic symphysis diastasis caused by high-energy trauma. The purpose of this retrospective study was to assess the clinical application of modified pedicle screw-rod fixation (modified PSRF) and open reduction plate fixation (ORPF) for treating pubic symphysis diastasis. Methods: The data of this retrospective analysis were collected from 32 patients with pubic symphysis diastasis managed with modified PSRF or ORPF from January 2012 to December 2017, with or without posterior fixation. Indicators of clinical assessments including operating time, intraoperative blood loss, relevant surgical complications as well as follow-up were recorded. Majeed scores were performed for functional evaluation, as well as Matta criteria were applied to evaluate the quality of reduction. Results: The average time from injury to operation was 2.9 days in modified PSRF group and 3.2 days in ORPF group. Significant differences regarding average operation time (41.8 min versus 64.3 min) and average intraoperative blood loss (46.6 ml versus 304.6 ml) were presented between modified PSRF groups and ORPF group. Neither Majeed scores nor Matta evaluation showed a significant difference between two groups. In ORPF group, the incision infection occurred in one patient and two patients developed loosening of screws. In modified PSRF group, loosening of screws was found in one patient during the operative procedure and one patient experienced femoral nerve palsy. Irritation to the lateral femoral cutaneous nerve (LFCN) was detected in two patients in modified PSRF group. Conclusions: Satisfactory clinical outcomes were provided with applications of both fixation methods for treating pubic symphysis diastasis. Modified PSRF, as a minimal invasive technique, could serve as an effective and reasonable option for treating pubic symphysis diastasis.Level of evidence: III: retrospective cohort study.Trial registration: researchregistry3906.

The ARK2N-CK2 complex initiates transcription-coupled repair through enhancing the interaction of CSB with lesion-stalled RNAPII.

Transcription is extremely important for cellular processes but can be hindered by RNA polymerase II (RNAPII) pausing and stalling. Cockayne syndrome protein B (CSB) promotes the progression of paused RNAPII or initiates transcription-coupled nucleotide excision repair (TC-NER) to remove stalled RNAPII. However, the specific mechanism by which CSB initiates TC-NER upon damage remains unclear. In this study, we identified the indispensable role of the ARK2N-CK2 complex in the CSB-mediated initiation of TC-NER. The ARK2N-CK2 complex is recruited to damage sites through CSB and then phosphorylates CSB. Phosphorylation of CSB enhances its binding to stalled RNAPII, prolonging the association of CSB with chromatin and promoting CSA-mediated ubiquitination of stalled RNAPII. Consistent with this finding, Ark2n-/- mice exhibit a phenotype resembling Cockayne syndrome. These findings shed light on the pivotal role of the ARK2N-CK2 complex in governing the fate of RNAPII through CSB, bridging a critical gap necessary for initiating TC-NER.

[Experimental study on promotion of peripheral nerve regeneration by selenium-methylselenocysteine].

Objective: To investigate the feasibility of selenium-methylselenocysteine (SMC) to promote peripheral nerve regeneration and its mechanism of action. Methods: Rat Schwann cells RSC96 cells were randomly divided into 5 groups, which were group A (without any treatment, control group), group B (adding 100 µmol/L H 2O 2), group C (adding 100 µmol/L H 2O 2+100 µmol/L SMC), group D (adding 100 µmol/L H 2O 2+200 µmol/L SMC), group E (adding 100 µmol/L H 2O 2+400 µmol/L SMC); the effect of SMC on cell proliferation was detected by MTT method, and the level of oxidative stress was detected by immunofluorescence for free radicals [reactive oxygen species (ROS)] after determining the appropriate dose group. Thirty-six 4-week-old male Sprague Dawley rats were randomly divided into 3 groups, namely, the sham operation group (Sham group), the sciatic nerve injury group (PNI group), and the SMC treatment group (SMC group), with 12 rats in each group; the rats in the PNI group were fed with food and water normally after modelling operation, and the rats in the SMC group were added 0.75 mg/kg SMC to the drinking water every day. At 4 weeks after operation, the sciatic nerves of rats in each group were sampled for neuroelectrophysiological detection of highest potential of compound muscle action potential (CMAP). The levels of inflammatory factors [interleukin 17 (IL-17), IL-6, IL-10 and oxidative stress factors catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA)] were detected by ELISA assay. The luxol fast blue (LFB) staining was used to observe the myelin density, fluorescence intensity of glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) was observed by immunofluorescence staining, and myelin morphology was observed by transmission electron microscopy with measurement of axon diameter. Western blot was used to detect the protein expressions of p38 mitogen-activated protein kinases (p38MAPK), phosphorylated p38MAPK (p-p38MAPK), heme oxygenase 1 (HO-1), and nuclear factor erythroid 2-related factor 2 (Nrf2). Results: MTT assay showed that the addition of SMC significantly promoted the proliferation of RSC96 cells, and the low concentration could achieve an effective effect, so the treatment method of group C was selected for the subsequent experiments; ROS immunofluorescence test showed that group B showed a significant increase in the intensity of ROS fluorescence compared with that of group A, and group C showed a significant decrease in the intensity of ROS fluorescence compared with that of group B ( P<0.05). Neuroelectrophysiological tests showed that the highest potential of CMAP in SMC group was significantly higher than that in PNI and Sham groups ( P<0.05). ELISA assay showed that the levels of IL-6, IL-17, and MDA in PNI group were significantly higher than those in Sham group, and the levels of IL-10, SOD, and CAT were significantly lower; the levels of IL-6, IL-17, and MDA in SMC group were significantly lower than those in PNI group, and the levels of IL-10, SOD, and CAT were significantly higher ( P<0.05). LFB staining and transmission electron microscopy showed that the myelin density and the diameter of axons in the SMC group were significantly higher than those of the PNI group and the Sham group ( P<0.05). Immunofluorescence staining showed that the fluorescence intensity of GFAP and MBP in the SMC group were significantly stronger than those in the PNI group and Sham group ( P<0.05). Western blot showed that the relative expressions of Nrf2 and HO-1 proteins in the SMC group were significantly higher than those in the PNI group and Sham group, and the ratio of p-p38MAPK/p38MAPK proteins was significantly higher in the PNI group than that in the SMC group and Sham group ( P<0.05). Conclusion: SMC may inhibit oxidative stress and inflammation after nerve injury by up-regulating the Nrf2/HO-1 pathway, and then inhibit the phosphorylation of p38MAPK pathway to promote the proliferation of Schwann cells, which ultimately promotes the formation of myelin sheaths and accelerates the regeneration of peripheral nerves.

Expert consensus on Prospective Precision Diagnosis and Treatment Strategies for Osteoporotic Fractures.

Osteoporotic fractures are the most severe complications of osteoporosis, characterized by poor bone quality, difficult realignment and fixation, slow fracture healing, and a high risk of recurrence. Clinically managing these fractures is relatively challenging, and in the context of rapid aging, they pose significant social hazards. The rapid advancement of disciplines such as biophysics and biochemistry brings new opportunities for future medical diagnosis and treatment. However, there has been limited attention to precision diagnosis and treatment strategies for osteoporotic fractures both domestically and internationally. In response to this, the Chinese Medical Association Orthopaedic Branch Youth Osteoporosis Group, Chinese Geriatrics Society Geriatric Orthopaedics Committee, Chinese Medical Doctor Association Orthopaedic Physicians Branch Youth Committee Osteoporosis Group, and Shanghai Association of Integrated Traditional Chinese and Western Medicine Osteoporosis Professional Committee have collaborated to develop this consensus. It aims to elucidate emerging technologies that may play a pivotal role in both diagnosis and treatment, advocating for clinicians to embrace interdisciplinary approaches and incorporate these new technologies into their practice. Ultimately, the goal is to improve the prognosis and quality of life for elderly patients with osteoporotic fractures.

Bromocriptine protects perilesional spinal cord neurons from lipotoxicity after spinal cord injury.

Recent studies have revealed that lipid droplets accumulate in neurons after brain injury and evoke lipotoxicity, damaging the neurons. However, how lipids are metabolized by spinal cord neurons after spinal cord injury remains unclear. Herein, we investigated lipid metabolism by spinal cord neurons after spinal cord injury and identified lipid-lowering compounds to treat spinal cord injury. We found that lipid droplets accumulated in perilesional spinal cord neurons after spinal cord injury in mice. Lipid droplet accumulation could be induced by myelin debris in HT22 cells. Myelin debris degradation by phospholipase led to massive free fatty acid production, which increased lipid droplet synthesis, ß-oxidation, and oxidative phosphorylation. Excessive oxidative phosphorylation increased reactive oxygen species generation, which led to increased lipid peroxidation and HT22 cell apoptosis. Bromocriptine was identified as a lipid-lowering compound that inhibited phosphorylation of cytosolic phospholipase A2 by reducing the phosphorylation of extracellular signal-regulated kinases 1/2 in the mitogen-activated protein kinase pathway, thereby inhibiting myelin debris degradation by cytosolic phospholipase A2 and alleviating lipid droplet accumulation in myelin debris-treated HT22 cells. Motor function, lipid droplet accumulation in spinal cord neurons and neuronal survival were all improved in bromocriptine-treated mice after spinal cord injury. The results suggest that bromocriptine can protect neurons from lipotoxic damage after spinal cord injury via the extracellular signal-regulated kinases 1/2-cytosolic phospholipase A2 pathway.

Research progress on the reduced neural repair ability of aging Schwann cells.

Peripheral nerve injury (PNI) is associated with delayed repair of the injured nerves in elderly patients, resulting in loss of nerve function, chronic pain, muscle atrophy, and permanent disability. Therefore, the mechanism underlying the delayed repair of peripheral nerves in aging patients should be investigated. Schwann cells (SCs) play a crucial role in repairing PNI and regulating various nerve-repair genes after injury. SCs also promote peripheral nerve repair through various modalities, including mediating nerve demyelination, secreting neurotrophic factors, establishing Büngner bands, clearing axon and myelin debris, and promoting axon remyelination. However, aged SCs undergo structural and functional changes, leading to demyelination and dedifferentiation disorders, decreased secretion of neurotrophic factors, impaired clearance of axonal and myelin debris, and reduced capacity for axon remyelination. As a result, aged SCs may result in delayed repair of nerves after injury. This review article aimed to examine the mechanism underlying the diminished neural repair ability of aging SCs.

4D printed tri-segment nerve conduit using zein gel as the ink for repair of rat sciatic nerve large defect.

Zein has enormous potential for application in biomedical field due to biodegradation and biocompatibility, we have recently prepared zein gel as a possible 3D printing ink. Our previous studies found that the pore structure in zein material can reduce early inflammation, promote the polarization of macrophages toward the M2 phenotype, and accelerate nerve regeneration. To further explore the role of zein in nerve repair, we used 4D printing technique to create nerve conduits with zein protein gel, and designed 2 types of tri-segment conduits with different degradation rates. Structural parts printed in support baths with higher water content show faster degradation rates than those printed in support baths with lower water content. The conduits that degraded quickly at both ends and slowly in the middle (CB75-CB40-CB75) and the conduits that degraded slowly at both ends and quickly in the middle (CB40-CB75-CB40) were 4D printed, respectively. Animal experiments suggest that the CB75-CB40-CB75 conduit is better for nerve repair, which may be because its degradation pattern can match to the pattern of nerve regeneration better. Our new strategy through 4D printing indicated that fine modulation in conduit degradation can affect efficacy of nerve repair significantly.

Fecal Microbiota Transplantation Revealed a Pain-related Gut Microbiota Community in Ovariectomized Mice.

Higher sensitivity to pain is a common clinical symptom in postmenopausal females. The gut microbiota (GM) has recently been identified as participating in various pathophysiological processes and may change during menopause and contribute to multiple postmenopausal symptoms. Here, we investigated the possible correlation between GM alteration and allodynia in ovariectomized (OVX) mice. Results showed that OVX mice exhibited allodynia from 7 weeks after surgery compared with sham-operated (SHAM) mice by comparing pain-related behaviors. Fecal microbiota transplantation (FMT) from OVX mice induced allodynia in normal mice while FMT from SHAM mice alleviated allodynia in OVX mice. Microbiome 16S rRNA sequencing and linear discriminant analysis revealed alteration of the GM after OVX. Furthermore, Spearman's correlation analysis showed associations between pain-related behaviors and genera, and further verification identified the possible pain-related genera complex. Our findings provide new insights into the underlying mechanisms of postmenopausal allodynia, and suggest pain-related microbiota community as a promising therapeutic target. PERSPECTIVE: This article provided the evidence of gut microbiota playing essential roles in postmenopausal allodynia. This work intended to offer a guidance for further mechanism investigation into gut-brain axis and probiotics screening for postmenopausal chronic pain.

Canceling Notch Improves the Mechanical Safety of Clavicle Locking Plate: A 3D Finite Element Study.

OBJECTIVE: Implant failure is a disastrous complication of the operative treatment of midshaft clavicle fractures, and improving the osteosynthesis plate is a strategy for preventing this. We aimed to investigate whether canceling the notch and adding screw-hole inserts enhanced the mechanical properties of the plate. METHODS: A clavicle model was generated based on the CT images of six adult volunteers (age range, 20-40 years; three males and three females; height range 160-175) using dedicated software, and a midshaft fracture model was created. The domestically made seven-hole locking plate commonly used for midshaft clavicle fractures was simulated (Model I); modifications were made to the plate (Model II). Using 3D finite element analysis, we simulated the fracture construct under three different load conditions-downward cantilever bending, axial compression, and axial torsion-and compared the stress distribution. RESULTS: We found that under axial compression, Model II experienced its maximum stress on the plate at 551.9MPa, which was less than that in Model I (790.4 MPa). Moreover, a greater stress concentration at the fracture site was observed under axial torsion, despite the maximum stress of both the models being similar. CONCLUSION: Canceling the notch and filling the screw holes near the fracture can ameliorate stress concentration on the internal fixation construct and enhance its reliability under axial compression. This improvement has substantial effects on the mechanical properties of implants and potentially prevents implant failure. Modern osteosynthesis anatomical implants need to be improved.

A Novel and Open Classification Emphasizing on Osteoligamentous Complex for Distal Clavicle Fractures.

OBJECTIVE: Current X-ray-based classification methods cannot describe all distal clavicle fracture (DCF) patterns, especially the osteoligamentous injury pattern of DCFs. We aimed to develop a novel classification based on the osteoligamentous injury pattern of the DCFs and investigated its reliability. METHODS: All DCFs from January 2017 to January 2022 were respectively screened and 45 cases (mean age 20-78; male 31, female 14) met the including criteria and were enrolled. Based on their Zanca view X-ray radiograph and three-dimensional CT construction images, we analyzed the osteoligamentous injury pattern of each case, particularly the acromioclavicular (AC) and coracoclavicular ligaments and their bone attachment. Then we developed a novel classification method, five types in total, sorting all DCFs according to their lesion manifestations of osteoligamentous complex. Also, we investigated the inter- and intra-observer reliability using kappa value. RESULTS: A novel classification method for DCF was developed, manifesting the avulsion or rupture of conoid and trapezoid ligaments, and involvement of AC joint. Forty-five cases of DCFs were included in this study. Among them, 11 (24.4%) were Type 1 fracture, three (6.7%) cases were Type 2, six cases (13.3%) were Type 3, 21 (46.7%) were Type 4, four (8.9%) were Type 5. Kappa values for inter-observer agreement were 0.57 after first evaluation and 0.61 after second evaluation. Intra-observer agreement was 0.72 for experienced shoulder specialist and 0.63 for radiologist. CONCLUSION: This new classification method is reliable to use, supplementary to current classification systems, and emphasizes on the osteoligamentous complex injury when opting for the treatment.

DNA methyltransferases are complementary in maintaining DNA methylation in embryonic stem cells.

ZFP57 and ZFP445 maintain genomic imprinting in mouse embryos. We found DNA methylation was lost at most examined imprinting control regions (ICRs) in mouse Zfp57 mutant ES cells, which could not be prevented by the elimination of three TET proteins. To elucidate methylation maintenance mechanisms, we generated mutant ES clones lacking three major DNA methyltransferases (DNMTs). Intriguingly, DNMT3A and DNMT3B were essential for DNA methylation at a subset of ICRs in mouse ES cells although DNMT1 maintained DNA methylation at most known ICRs. These were similarly observed after extended culture. Germline-derived DNA methylation was lost at the examined ICRs lacking DNMTs according to allelic analysis. Similar to DNMT1, DNMT3A and DNMT3B were required for maintaining DNA methylation at repeats, genic regions, and other genomic sequences. Therefore, three DNA methyltransferases play complementary roles in maintaining DNA methylation in mouse ES cells including DNA methylation at the ICRs primarily mediated through the ZFP57-dependent pathway.

Upregulated lncARAT in Schwann cells promotes axonal regeneration by recruiting and activating proregenerative macrophages.

BACKGROUND: Axonal regeneration following peripheral nerve injury (PNI) depends on the complex interaction between Schwann cells (SCs) and macrophages, but the mechanisms underlying macrophage recruitment and activation in axonal regeneration remain unclear. METHODS: RNA sequencing (RNA-seq) was conducted to identify differentially expressed long noncoding RNAs (DElncRNAs) between crushed sciatic nerves and intact contralateral nerves. The putative role of lncRNAs in nerve regeneration was analyzed in vitro and in vivo. RESULTS: An lncRNA, called axon regeneration-associated transcript (lncARAT), was upregulated in SCs and SC-derived exosomes (SCs-Exo) after sciatic nerve injury. LncARAT contributed to axonal regeneration and improved motor function recovery. Mechanistically, lncARAT epigenetically activated C-C motif ligand 2 (CCL2) expression by recruiting KMT2A to CCL2 promoter, resulting in increased histone 3 lysine 4 trimethylation (H3K4me3) and CCL2 transcription in SCs. CCL2 facilitated the infiltration of macrophages into the injured nerves. Meanwhile, lncARAT-enriched exosomes were released from SCs and incorporated into macrophages. LncARAT functioned as an endogenous sponge to adsorb miRNA-329-5p in macrophages, resulting in increased suppressor of cytokine signaling (SOCS) 2 expression, which induced a proregenerative function of macrophages through a signal transducer and activator of transcription (STAT) 1/6-dependent pathway. CONCLUSIONS: LncARAT may represent a promising therapeutic avenue for peripheral nerve repair.

Statistic Copolymers Working as Growth Factor-Binding Mimics of Fibronectin.

Growth factors (GFs) play important roles in biological system and are widely used in tissue regeneration. However, their application is greatly hindered by short in vivo lifetime of GFs. GFs are bound to fibronectin dynamically in the extracellular matrix, which inspired the authors to mimic the GF binding domain of fibronectin and design GF-binding amphiphilic copolymers bearing positive charges. The optimal amino acid polymer can bind to a variety of representative GFs, such as bone morphogenetic protein-2 (BMP-2) and TGF-ß1 from the transforming growth factor-ß superfamily, PDGF-AA and PDGF-BB from the platelet-derived growth factor family, FGF-10 and FGF-21 from the fibroblast growth factor family, epidermal growth factor from the EGF family and hepatocyte growth factor from the plasminogen-related growth factor family, with binding affinities up to the nanomolar level. 3D scaffolds immobilized with the optimal copolymer enable sustained release of loaded BMP-2 without burst release and significantly enhances the in vivo function of BMP-2 for bone formation. This strategy opens new avenues in designing GF-binding copolymers as synthetic mimics of fibronectin for diverse applications.

Zein-induced immune response and modulation by size, pore structure and drug-loading: Application for sciatic nerve regeneration.

Zein is a biodegradable material with great potential in biomedical applications. However, as a plant-derived protein material, body's immune response is the key factor to determine its clinical performance. Herein, for the first time, the zein-induced immune response is evaluated systemically and locally, comparing with typical materials including alginate (ALG), poly(lactic-co-glycolic) acid (PLGA) and polystyrene (PS). Zein triggers an early inflammatory response consistent with the non-degradable PS, but this response decreases to the same level of the biosafe ALG and PLGA with zein degradation. Changing sphere sizes, pore structure and encapsulating dexamethasone can effectively modulate the zein-induced immune response, especially the pore structure which also inhibits neutrophil recruitment and promotes macrophages polarizing towards M2 phenotype. Thus, porous zein conduits with high and low porosity are further fabricated for the 15 mm sciatic nerve defect repair in rats. The conduits with high porosity induce more M2 macrophages to accelerate nerve regeneration with shorter degradation period and better nerve repair efficacy. These findings suggest that the pore structure in zein materials can alleviate the zein-induced early inflammation and promote M2 macrophage polarization to accelerate nerve regeneration. STATEMENT OF SIGNIFICANCE: Zein is a biodegradable material with great potential in biomedical applications. However, as a plant protein, its possible immune response in vivo is always the key issue. Until now, the systemic study on the immune responses of zein in vivo is still very limited, especially as an implant. Herein, for the first time, the zein-induced immune response was evaluated systemically and locally, comparing with typical biomaterials including alginate, poly(lactic-co-glycolic) acid and polystyrene. Changing sphere sizes, pore structure and encapsulating dexamethasone could effectively modulate the zein-induced immune response, especially the pore structure which also inhibited neutrophil recruitment and promoted macrophages polarizing towards M2 phenotype. Furthermore, the pore structure in zein nerve conduits was proved to alleviate the early inflammation and promote M2 macrophage polarization to accelerate nerve regeneration.

[Regulatory role of long non-coding RNA in peripheral nerve injury and neural regeneration].

OBJECTIVE: To summarize the regulatory role of long non-coding RNA (lncRNA) in peripheral nerve injury (PNI) and neural regeneration. METHODS: The characteristics and mechanisms of lncRNA were summarized and its regulatory role in PNI and neural regeneration were elaborated by referring to relevant domestic and foreign literature in recent years. RESULTS: Neuropathic pain and denervated muscle atrophy are common complications of PNI, affecting patients' quality of life. Numerous lncRNAs are upregulated after PNI, which promote the progress of neuropathic pain by regulating nerve excitability and neuroinflammation. Several lncRNAs are found to promote the progress of denervated muscle atrophy. Importantly, peripheral nerve regeneration occurs after PNI. LncRNAs promote peripheral nerve regeneration through promoting neuronal axonal outgrowth and the proliferation and migration of Schwann cells. CONCLUSION: At present, the research on lncRNA regulating PNI and neural regeneration is still in its infancy. The specific mechanism remains to be further explored. How to achieve clinical translation of experimental results is also a major challenge for future research.

Contralateral S1 nerve root transfer for motor function recovery in the lower extremity among patients with central nervous system injury: study protocol for a randomized controlled trial.

BACKGROUND: Central nervous system injury (CNSI) comprises a series of common diseases that severely affect patients' motor function and quality of life and is associated with high disability and mortality rates. Previous studies have shown that contralateral lumbosacral nerve root transfer significantly improved the function of the paralyzed limb in rat models of CNSI. These studies showed that severing the sacral 1 nerve root (S1) did not damage the function of the ipsilateral lower extremity. Thus, we speculate that contralateral S1 nerve root transfer can improve the recovery of a paralyzed limb. Because no associated rigorously designed randomized controlled trial has evaluated the effectiveness of contralateral S1 nerve transfer thus far, we designed this clinical trial to compare the effects of this new treatment approach with those of traditional treatments in paralyzed patients after chronic CNSI. METHODS: This is a single-center, prospective, randomized controlled trial. Forty patients, who meet the inclusion criteria and have hemiplegia caused by chronic CNSI, will be randomly divided into the surgical or non-surgical group. The treatment effect in the 2 groups will be assessed before and 3, 6, 9, 12, 18, and 24 months after intervention by using numerous scales and resting-state functional magnetic resonance imaging. The primary outcome will be the Fugl-Meyer score for the lower limbs 24 months after treatment. The secondary outcomes include the modified Ashworth spasm scale, the modified Barthel scale, 10-m walking speed measurement results, three-dimensional gait analysis, muscle strength testing, electromyography, and resting-state functional magnetic resonance imaging findings. Safety outcomes and adverse events will be observed simultaneously. DISCUSSION: We expect that the surgery will improve the sensorimotor functions of the paralyzed limb, and the results of this trial will provide high-quality clinical evidence for a new efficient treatment strategy for disability after CNSI. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR1800014414, registration date: 12 January 2018.

MicroRNA-182 improves spinal cord injury in mice by modulating apoptosis and the inflammatory response via IKKß/NF-κB.

Spinal cord injury (SCI) is one common neurological condition which involves primary injury and secondary injury. Neuron inflammation and apoptosis after SCI is the most important pathological process of this disease. Here, we tried to explore the influence and mechanism of miRNAs on the neuron inflammatory response and apoptosis after SCI. First, by re-analysis of Gene Expression Omnibus dataset (accession GSE19890), miR-182 was selected for further study because of its suppressive effects on the inflammatory response in the various types of injuries. Functional experiments demonstrated that miR-182 overexpression promoted functional recovery, reduced histopathological changes, and alleviated spinal cord edema in mice. It was also observed that miR-182 overexpression reduced apoptosis and attenuated the inflammatory response in spinal cord tissue, as evidenced by the reduction of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1ß, and the induction of IL-10. Using a lipopolysaccharide (LPS)-induced SCI model in BV-2 cells, we found that miR-182 was downregulated in the BV-2 cells following LPS stimulation, and upregulation of miR-182 improved LPS-induced cell damage, as reflected by the inhibition of apoptosis and the inflammatory response. IκB kinase ß (IKKß), an upstream target of the NF-κB pathway, was directly targeted by miR-182 and miR-182 suppressed its translation. Further experiments revealed that overexpression of IKKß reversed the anti-apoptosis and anti-inflammatory effects of miR-182 in LPS stimulated BV-2 cells. Finally, we found that miR-182 overexpression blocked the activation of the NF-κB signaling pathway in vitro and in vivo, as demonstrated by the downregulation of phosphorylated (p­) IκB-α and nuclear p-p65. Taken together, these data indicate that miR-182 improved SCI-induced secondary injury through inhibiting apoptosis and the inflammatory response by blocking the IKKß/NF-κB pathway. Our findings suggest that upregulation of miR-182 may be a novel therapeutic target for SCI.

Long Non-coding RNA MSTRG.24008.1 Regulates the Regeneration of the Sciatic Nerve via the miR-331-3p-NLRP3/MAL Axis.

Peripheral nerve injury (PNI) is a common clinical problem, which can cause severe disability and dramatically affect a patient's quality of life. Neural regeneration after PNI is a complex biological process that involves a variety of signaling pathways and genes. Emerging studies demonstrated that long non-coding RNAs (lncRNAs) were abnormally expressed after PNI and played pivotal roles in peripheral nerve regeneration. Based on the rat sciatic nerve injury model, we found that the expression levels of several lncRNAs were increased significantly in the sciatic nerve after injury. Software prediction prompted us to focus on one up-regulated lncRNA, MSTRG.24008.1. Dual-luciferase reporter assay, RNA pull-down assay and RNA interference approach verified that MSTRG.24008.1 regulated neuroregeneration via the miR-331-3p/nucleotide-binding oligomerization domain-like pyrin domain containing 3 (NLRP3)/myelin and lymphocyte protein (MAL) axis in vitro. Subsequently, we performed gastrocnemius muscle gravity and sciatic functional index experiments to evaluate the recovery of injured sciatic nerves after MSTRG.24008.1 siRNA interference in vivo. In conclusion, knockdown of MSTRG.24008.1 promotes the regeneration of the sciatic nerve via the miR-331-3p/NLRP3/MAL axis, which may provide a new strategy to evaluate and repair injured peripheral nerves clinically.

Silencing of Long Noncoding RNA Growth Arrest-Specific 5 Alleviates Neuronal Cell Apoptosis and Inflammatory Responses Through Sponging microRNA-93 to Repress PTEN Expression in Spinal Cord Injury.

A secondary injury induced by a spinal cord injury (SCI) remains the main cause of devastating neural dysfunction; therefore, it has been the subject of focused research for many years. Long noncoding RNA (lncRNA) has been found to participate in the SCI process, and this finding presents a high potential for diagnosis and treatment; however, the role of lncRNA in a secondary injury induced by SCI remains unclear. The aim of this study was to investigate the regulatory effect of lncRNA growth arrest-specific transcript 5 (GAS5) in secondary injury during SCI. The SCI mice model and hypoxic cellular model were established to research the roles of lncRNA GAS5 during SCI. Reverse transcription quantitative polymerase chain reaction (qRT-PCR) was conducted to determine the expression levels of microR-93 (miR-93) and lncRNA GAS5. Western blot analysis of the apoptosis regulator protein and terminal deoxynucleotidyl transferase dUTP nick end labeling assay was conducted to evaluate neuron cell apoptosis. Basso, Beattie, and Bresnahan (BBB) scores were calculated to assess neurological function. Flow cytometry was used to determine neuron cell apoptosis. The associations among GAS5, miR-93, and the phosphatase and tensin homolog (PTEN) were disclosed using RNA immunoprecipitation (RIP) assay, RNA pulldown assay, and dual-luciferase reporter assay. QRT-PCR demonstrated that GAS5 was significantly upregulated in both the SCI mice and hypoxic cellular models. GAS5 knockdown suppressed neuron cell apoptosis and inflammatory response in the SCI mice model. Further studies have indicated that GAS5 functions as a competing endogenous RNA (ceRNA) by sponging miR-93 in neuronal cells. In addition, PTEN was a target of miR-93, and GAS5 knockdown exhibited its anti-apoptotic and anti-inflammatory effects through the miR-93/PTEN axis. These findings suggest that the GAS5/miR-93/PTEN axis may be a promising therapeutic target for SCI.

Effective and biocompatible antibacterial surfaces via facile synthesis and surface modification of peptide polymers.

It is an urgent need to tackle drug-resistance microbial infections that are associated with implantable biomedical devices. Host defense peptide-mimicking polymers have been actively explored in recent years to fight against drug-resistant microbes. Our recent report on lithium hexamethyldisilazide-initiated superfast polymerization on amino acid N-carboxyanhydrides enables the quick synthesis of host defense peptide-mimicking peptide polymers. Here we reported a facile and cost-effective thermoplastic polyurethane (TPU) surface modification of peptide polymer (DLL: BLG = 90 : 10) using plasma surface activation and substitution reaction between thiol and bromide groups. The peptide polymer-modified TPU surfaces exhibited board-spectrum antibacterial property as well as effective contact-killing ability in vitro. Furthermore, the peptide polymer-modified TPU surfaces showed excellent biocompatibility, displaying no hemolysis and cytotoxicity. In vivo study using methicillin-resistant Staphylococcus aureus (MRSA) for subcutaneous implantation infectious model showed that peptide polymer-modified TPU surfaces revealed obvious suppression of infection and great histocompatibility, compared to bare TPU surfaces. We further explored the antimicrobial mechanism of the peptide polymer-modified TPU surfaces, which revealed a surface contact-killing mechanism by disrupting the bacterial membrane. These results demonstrated great potential of the peptide-modified TPU surfaces for practical application to combat bacterial infections that are associated with implantable materials and devices.