Machine learning and experiments revealed a novel pyroptosis-based classification linked to diagnosis and immune landscape in spinal cord injury.

Background: Rising evidence indicates the development of pyroptosis in the initiation and pathogenesis of spinal cord injury (SCI). However, the associated effects of pyroptosis-related genes (PRGs) in SCI are unclear. Methods: We obtained the gene expression profiles of SCI and normal samples in the GEO. Database: The R package limma screened for differentially expressed (DE) PRGs and performed functional enrichment analysis. Mechanical learning and PPI analysis helped filter essential PRGs to diagnose SCI. Peripheral blood was collected for validation from ten SCI patients and eight healthy individuals. The association of essential PRGs with immune infiltration was evaluated, and pyroptosis subtypes were recognized in SCI patients by unsupervised cluster analysis. Besides, a SCI model was built for in vivo validation of essential PRGs. Result: We identified 25 DE-PRGs between SCI and normal controls. Functional enrichment analysis revealed the principal involvement of DE-PRGs in pyroptosis, inflammasome complex, interleukin-1 beta production, etc. Subsequently, three essential PRGs were identified and validated, showing excellent diagnostic efficacy and significant correlation with immune cell infiltration. Additionally, we developed diagnostic nomograms to predict the occurrence of SCI. Two pyroptosis subtypes exhibited distinct biological functions and immune landscapes among SCI patients. Finally, the expression of these essential PRGswas verified in vivo. Conclusion: The current study described the vital effects of pyroptosis-related genes in SCI, providing a novel direction for effective assessment and management of SCI.

Photobiomodulation Increases M2-Type Polarization of Macrophages by Inhibiting Versican Production After Spinal Cord Injury.

Spinal cord injury (SCI) is a catastrophic accidence with little effective treatment, and inflammation played an important role in that. Previous studies showed photobiomodulation (PBM) could effectively downregulate the process of inflammation with modification of macrophage polarization after SCI; however, the potential mechanism behind that is still unclear. In the presented study, we aimed to investigate the effect of PBM on the expression level of versican, a matrix molecular believed to be associated with inflammation, and tried to find the mechanism on how that could regulate the inflammation process. Using immunofluorescence technique and western blot, we found the expression level of versican is increased after injury and markedly downregulated by irradiation treatment. Using virus intrathecal injection, we found the knock-down of versican could produce the effect similar to that of PBM and might have an effect on inflammation and macrophage polarization after SCI. To further verify the deduction, we peptide the supernatant of astrocytes to induce M0, M1, and M2 macrophages. We found that the versican produced by astrocytes might have a role on the promotion of M2 macrophages to inflammatory polarization. Finally, we investigated the potential pathway in the regulation of M2 polarization with the induction of versican. This study tried to give an interpretation on the mechanism of inflammation inhibition for PBM in the perspective of matrix regulation. Our results might provide light on the inflammation regulation after SCI.

Photobiomodulation reduces neuropathic pain after spinal cord injury by downregulating CXCL10 expression.

BACKGROUND: Many studies have recently highlighted the role of photobiomodulation (PBM) in neuropathic pain (NP) relief after spinal cord injury (SCI), suggesting that it may be an effective way to relieve NP after SCI. However, the underlying mechanisms remain unclear. This study aimed to determine the potential mechanisms of PBM in NP relief after SCI. METHODS: We performed systematic observations and investigated the mechanism of PBM intervention in NP in rats after SCI. Using transcriptome sequencing, we screened CXCL10 as a possible target molecule for PBM intervention and validated the results in rat tissues using reverse transcription-polymerase chain reaction and western blotting. Using immunofluorescence co-labeling, astrocytes and microglia were identified as the cells responsible for CXCL10 expression. The involvement of the NF-κB pathway in CXCL10 expression was verified using inhibitor pyrrolidine dithiocarbamate (PDTC) and agonist phorbol-12-myristate-13-acetate (PMA), which were further validated by an in vivo injection experiment. RESULTS: Here, we demonstrated that PBM therapy led to an improvement in NP relative behaviors post-SCI, inhibited the activation of microglia and astrocytes, and decreased the expression level of CXCL10 in glial cells, which was accompanied by mediation of the NF-κB signaling pathway. Photobiomodulation inhibit the activation of the NF-κB pathway and reduce downstream CXCL10 expression. The NF-κB pathway inhibitor PDTC had the same effect as PBM on improving pain in animals with SCI, and the NF-κB pathway promoter PMA could reverse the beneficial effect of PBM. CONCLUSIONS: Our results provide new insights into the mechanisms by which PBM alleviates NP after SCI. We demonstrated that PBM significantly inhibited the activation of microglia and astrocytes and decreased the expression level of CXCL10. These effects appear to be related to the NF-κB signaling pathway. Taken together, our study provides evidence that PBM could be a potentially effective therapy for NP after SCI, CXCL10 and NF-kB signaling pathways might be critical factors in pain relief mediated by PBM after SCI.

Photobiomodulation augments the effects of mitochondrial transplantation in the treatment of spinal cord injury in rats by facilitating mitochondrial transfer to neurons via Connexin 36.

Mitochondrial transplantation is a promising treatment for spinal cord injury (SCI), but it has the disadvantage of low efficiency of mitochondrial transfer to targeted cells. Here, we demonstrated that Photobiomodulation (PBM) could promote the transfer process, thus augmenting the therapeutic effect of mitochondrial transplantation. In vivo experiments, motor function recovery, tissue repair, and neuronal apoptosis were evaluated in different treatment groups. Under the premise of mitochondrial transplantation, the expression of Connex36 (Cx36), the trend of mitochondria transferred to neurons, and its downstream effects, such as ATP production and antioxidant capacity, were evaluated after PBM intervention. In in vitro experiments, dorsal root ganglia (DRG) were cotreated with PBM and 18ß-GA (a Cx36 inhibitor). In vivo experiments showed that PBM combined with mitochondrial transplantation could increase ATP production and reduce oxidative stress and neuronal apoptosis levels, thereby promoting tissue repair and motor function recovery. In vitro experiments further verified that Cx36 mediated the transfer of mitochondria into neurons. PBM could facilitate this progress via Cx36 both in vivo and in vitro. The present study reports a potential method of using PBM to facilitate the transfer of mitochondria to neurons for the treatment of SCI.

Photobiomodulation provides neuroprotection through regulating mitochondrial fission imbalance in the subacute phase of spinal cord injury.

Increasing evidence indicates that mitochondrial fission imbalance plays an important role in delayed neuronal cell death. Our previous study found that photobiomodulation improved the motor function of rats with spinal cord injury. However, the precise mechanism remains unclear. To investigate the effect of photobiomodulation on mitochondrial fission imbalance after spinal cord injury, in this study, we treated rat models of spinal cord injury with 60-minute photobiomodulation (810 nm, 150 mW) every day for 14 consecutive days. Transmission electron microscopy results confirmed the swollen and fragmented alterations of mitochondrial morphology in neurons in acute (1 day) and subacute (7 and 14 days) phases. Photobiomodulation alleviated mitochondrial fission imbalance in spinal cord tissue in the subacute phase, reduced neuronal cell death, and improved rat posterior limb motor function in a time-dependent manner. These findings suggest that photobiomodulation targets neuronal mitochondria, alleviates mitochondrial fission imbalance-induced neuronal apoptosis, and thereby promotes the motor function recovery of rats with spinal cord injury.

Potential targets and mechanisms of photobiomodulation for spinal cord injury.

As a classic noninvasive physiotherapy, photobiomodulation, also known as low-level laser therapy, is widely used for the treatment of many diseases and has anti-inflammatory and tissue repair effects. Photobiomodulation has been shown to promote spinal cord injury repair. In our previous study, we found that 810 nm low-level laser therapy reduced the M1 polarization of macrophages and promoted motor function recovery. However, the mechanism underlying this inhibitory effect is not clear. In recent years, transcriptome sequencing analysis has played a critical role in elucidating the progression of diseases. Therefore, in this study, we performed M1 polarization on induced mouse bone marrow macrophages and applied low-level laser therapy. Our sequencing results showed the differential gene expression profile of photobiomodulation regulating macrophage polarization. We analyzed these genes using gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. Networks of protein-protein interactions and competing RNA endogenous networks were constructed. We found that photobiomodulation inhibited STAT3 expression through increasing the expression of miR-330-5p, and that miR-330-5p binding to STAT3 inhibited STAT3 expression. Inducible nitric oxide synthase showed trends in changes similar to the changes in STAT3 expression. Finally, we treated a mouse model of spinal cord injury using photobiomodulation and confirmed that photobiomodulation reduced inducible nitric oxide synthase and STAT3 expression and promoted motor function recovery in spinal cord injury mice. These findings suggest that STAT3 may be a potential target of photobiomodulation, and the miR-330-5p/STAT3 pathway is a possible mechanism by which photobiomodulation has its biological effects.

A systematic morphology study on the effect of high glucose on intervertebral disc endplate degeneration in mice.

To explore the relationship between diabetes and intervertebral disc degeneration in mice and the associated underlying mechanism. Four-week-old male Kunming mice were used to model diabetes using a high-fat diet combined with streptozotocin injection. After 6 months, morphological and pathological changes in L4-L6 intervertebral discs were detected by magnetic resonance imaging, micro-CT and histological staining. Immunostaining of CD31, F4/80 and CD16/32 receptors was used to detect vascular invasion and inflammatory infiltration in endplates; the exact changes were then explored by the transmission electron microscopy. The nucleus pulposus of the control and the diabetic group had a clear boundary and regular shape without collapse, while endplate calcification and chondrocyte abnormality in the diabetic group were more obvious. Immunofluorescence confirmed that compared to control, expression levels of CD31 (vascular endothelial marker) and F4/80 (monocyte/macrophage marker) in the diabetic group were significantly increased (P < 0.05), with an elevated number of F4/80 (+)/CD16/32 (+) cells (P < 0.05). The morphology of endplates was observed by transmission electron microscopy, which showed monocytes/macrophage accumulation in the endplate of the diabetic group, accompanied by increased vascular density, collagen fiber distortion and chondrocyte abnormality. In a conclusion, diabetes promotes endplate degeneration with vascular invasion, monocyte/macrophage infiltration and inflammation in mice.

Comprehensive landscape of immune-based classifier related to early diagnosis and macrophage M1 in spinal cord injury.

Numerous studies have documented that immune responses are crucial in the pathophysiology of spinal cord injury (SCI). Our study aimed to uncover the function of immune-related genes (IRGs) in SCI. Here, we comprehensively evaluated the transcriptome data of SCI and healthy controls (HC) obtained from the GEO Database integrating bioinformatics and experiments. First, a total of 2067 DEGs were identified between the SCI and HC groups. Functional enrichment analysis revealed substantial immune-related pathways and functions that were abnormally activated in the SCI group. Immune analysis revealed that myeloid immune cells were predominantly upregulated in SCI patients, while a large number of lymphoid immune cells were dramatically downregulated. Subsequently, 51 major IRGs were screened as key genes involved in SCI based on the intersection of the results of WGCNA analysis, DEGs, and IRGs. Based on the expression profiles of these genes, two distinct immune modulation patterns were recognized exhibiting opposite immune characteristics. Moreover, 2 core IRGs (FCER1G and NFATC2) were determined to accurately predict the occurrence of SCI via machine learning. qPCR analysis was used to validate the expression of core IRGs in an external independent cohort. Finally, the expression of these core IRGs was validated by sequencing, WB, and IF analysis in vivo. We found that these two core IRGs were closely associated with immune cells and verified the co-localization of FCER1G with macrophage M1 via IF analysis. Our study revealed the key role of immune-related genes in SCI and contributed to a fresh perspective for early diagnosis and treatment of SCI.

Photobiomodulation promotes spinal cord injury repair by inhibiting macrophage polarization through lncRNA TUG1-miR-1192/TLR3 axis.

BACKGROUND: Secondary spinal cord injury (SCI) often causes the aggravation of inflammatory reaction and nerve injury, which affects the recovery of motor function. Bone-marrow-derived macrophages (BMDMs) were recruited to the injured area after SCI, and the M1 polarization is the key process for inducing inflammatory response and neuronal apoptosis. We previously showed that photobiomodulation (PBM) can inhibit the polarization of M1 phenotype of BMDMs and reduce inflammation, but the underlying mechanisms are unclear. The purpose of this study is to explore the potential target and mechanism of PBM in treating SCI. METHODS: Transcriptome sequencing and bioinformatics analysis showed that long noncoding RNA taurine upregulated gene 1 (lncRNA TUG1) was a potential target of PBM. The expression and specific mechanism of lncRNA TUG1 were detected by qPCR, immunofluorescence, flow cytometry, western blotting, fluorescence in situ hybridization, and luciferase assay. The Basso mouse scale (BMS) and gait analysis were used to evaluate the recovery of motor function in mice. RESULTS: Results showed that lncRNA TUG1 may be a potential target of PBM, regulating the polarization of BMDMs, inflammatory response, and the axial growth of DRG. Mechanistically, TUG1 competed with TLR3 for binding to miR-1192 and attenuated the inhibitory effect of miR-1192 on TLR3. This effect protected TLR3 from degradation, enabling the high expression of TLR3, which promoted the activation of downstream NF-κB signal and the release of inflammatory cytokines. In vivo, PBM treatment could reduce the expression of TUG1, TLR3, and inflammatory cytokines and promoted nerve survival and motor function recovery in SCI mice. CONCLUSIONS: Our study clarified that the lncRNA TUG1/miR-1192/TLR3 axis is an important pathway for PBM to inhibit M1 macrophage polarization and inflammation, which provides theoretical support for its clinical application in patients with SCI.

Epothilone B inactivation of Sirtuin1 promotes mitochondrial reactive oxygen species to induce dysfunction and ferroptosis of Schwann cells.

Epothilone B (EpoB) is an FDA-approved anti-neoplastic agent used to treat metastatic breast cancer; However, its usage is limited due to its severe peripheral neurotoxicity. Ferroptosis is a type of programmed cell death triggered by iron accumulation, and it is induced by lipid peroxidation. Ferroptosis has been linked to multiple diseases, including cancer, type 2 diabetes, and neurodegenerative disorders. Here, we assessed the role of ferroptosis in EpoB-induced neural dysfunction. Our results revealed that EpoB induced ferroptosis, which was significantly reduced by the ferroptosis inhibitor Fer-1. In addition, EpoB decreased the mitochondrial membrane potential and the cytochrome c levels in Schwann cells (SCs). The antioxidant MitoTEMPO, which targets the mitochondria, reduced ferroptosis brought on by EpoB. Moreover, we demonstrated that in vivo EpoB-induced myelin degradation and neuronal dysfunction were mitigated by SRT1720, a Sirtuin1 (SIRT1) activator, and by SRT1720 and mitoquinone mesylate (mitoQ). Our results suggest that ferroptosis elicited by EpoB is caused by mitochondrial damage mediated by SIRT1 inactivation and that ferroptosis causes neural dysfunction following EpoB.

Protective Effect of Photobiomodulation against Hydrogen Peroxide-Induced Oxidative Damage by Promoting Autophagy through Inhibition of PI3K/AKT/mTOR Pathway in MC3T3-E1 Cells.

Photobiomodulation (PBM) has been repeatedly reported to play a major role in the regulation of osteoblast proliferation and mineralization. Autophagy is closely associated with various pathophysiological processes in osteoblasts, while its role in oxidative stress is even more critical. However, there is still no clear understanding of the mechanism of the role of autophagy in the regulation of osteoblast mineralization and apoptosis under oxidative stress by PBM. It was designed to investigate the impact of 808 nm PBM on autophagy and apoptosis in mouse preosteoblast MC3T3-E1 treated with hydrogen peroxide (H2O2) through PI3K/AKT/mTOR pathway. PBM could inhibit MC3T3-E1 cell apoptosis under oxidative stress and promote the expression of osteogenic proteins, while enhancing the level of autophagy. In contrast, 3-methyladenine (3-MA) inhibited the expression of osteoblast autophagy under oxidative stress conditions, increased apoptosis, and plus counteracted the effect of PBM on osteoblasts. We also found that PBM suppressed the activated PI3K/AKT/mTOR pathway during oxidative stress and induced autophagy in osteoblasts. PBM promoted autophagy of MC3T3 cells and was further blocked by 740 Y-P, which reversed the effect of PBM on MC3T3 cells with H2O2. In conclusion, PBM promotes autophagy and improves the level of osteogenesis under oxidative stress by inhibiting the PI3K/AKT/mTOR pathway. Our results can lay the foundation for the clinical usage of PBM in the treatment of osteoporosis.

Photobiomodulation promotes repair following spinal cord injury by restoring neuronal mitochondrial bioenergetics via AMPK/PGC-1α/TFAM pathway.

Background: Insufficient neuronal mitochondrial bioenergetics supply occurs after spinal cord injury (SCI), leading to neuronal apoptosis and impaired motor function. Previous reports have shown that photobiomodulation (PBM) could reduce neuronal apoptosis and promote functional recovery, but the underlying mechanism remains unclear. Therefore, we aimed to investigate whether PBM improved prognosis by promoting neuronal mitochondrial bioenergetics after SCI. Methods: Sprague Dawley rats were randomly divided into four groups: a Sham group, an SCI group, an SCI + PBM group and an SCI + PBM + Compound C group. After SCI model was established, PBM and Compound C (an AMPK inhibitor) injection were carried out. The level of neuron apoptosis, the recovery of motor function and mitochondrial function were observed at different times (7, 14, and 28 days). The AMPK/PGC-1α/TFAM pathway was hypothesized to be a potential target through which PBM could affect neuronal mitochondrial bioenergetics. In vitro, ventral spinal cord 4.1 (VSC4.1) cells were irradiated with PBM and cotreated with Compound C after oxygen and glucose deprivation (OGD). Results: PBM promoted the recovery of mitochondrial respiratory chain complex activity, increased ATP production, alleviated neuronal apoptosis and reversed motor dysfunction after SCI. The activation of the AMPK/PGC-1α/TFAM pathway after SCI were facilitated by PBM but inhibited by Compound C. Equally important, PBM could inhibit OGD-induced VSC4.1 cell apoptosis by increasing ATP production whereas these changes could be abolished by Compound C. Conclusion: PBM activated AMPK/PGC-1α/TFAM pathway to restore mitochondrial bioenergetics and exerted neuroprotective effects after SCI.

Clinical safety study of photobiomodulation in acute spinal cord injury by scattering fiber.

The study aimed to design a reliable and straightforward PBM method by implanting a medical scattering fiber above surgically exposed spinal cord in SCI patients. Moreover, the safety of this method was examined. Twelve patients with acute SCI (ASIA B) requiring posterior decompression were recruited. The medical scattering fiber was implanted above the spinal cord, and was continuously irradiated at 810 nm, 300 mW, 30 min/day, once per day for 7 days. The vital signs (temperature, blood pressure, respiratory rate, heart rate, and oxygen saturation), infection indicators (WBC, NEUT, hs-CRP, and PCT), photo-allergic reaction indicators (Eosinophil and Basophil), coagulation function indicators (PT, APTT, TT) and neurological stability indicators (ASIA sensory and motor scores) were recorded to evaluate the safety of PBM. Three months after surgery, 12 patients completed follow-up. In our study, direct PBM on SCI site did not cause clinically pathologic changes in vital signs of the patients. All patients had higher WBC, NEUT, and hs-CRP at day 3 during irradiation than those before surgery, and returned to normal at day 7. The changes in Eosinophil and Basophil that were closely associated with allergic reactions were within normal limits throughout the course of irradiation. The coagulation function (PT, APTT, and TT) of patients were also in the normal range. The ASIA sensory and motor scores of all patients had no changes throughout the irradiation process. However, in the follow-up, both ASIA sensory and motor scores of all patients had minor improvement than those in pre-irradiation, and 7 patients had adverse events, but they were not considered to be related to PBM. Our study might firstly employ direct PBM in the SCI by using scattered optical fibers. In a limited sample size, our study concluded that direct PBM at the site of SCI would not produce adverse effects within the appropriate irradiation parameters. The method is safe, feasible, and does not add additional trauma to the patient. Our preliminary study might provide a new methodology for the clinical PBM treatment of acute SCI.

Photobiomodulation Attenuates Neurotoxic Polarization of Macrophages by Inhibiting the Notch1-HIF-1α/NF-κB Signalling Pathway in Mice With Spinal Cord Injury.

Spinal cord injury (SCI) is a catastrophic disease with a complex pathogenesis that includes inflammation, oxidative stress, and glial scar formation. Macrophages are the main mediators of the inflammatory response and are distributed in the epicentre of the SCI. Macrophages have neurotoxic and neuroprotective phenotypes (also known as classically and alternatively activated macrophages or M1 and M2 macrophages) that are associated with pro- or anti- inflammatory gene expression. Our previous study demonstrated that photobiomodulation (PBM) alters the polarization state of macrophages in the SCI region towards the M2 phenotype and promotes the recovery of motor function in rats with SCI. However, the mechanism by which PBM promotes SCI repair remains largely undefined. This study is based on the replacement of conventional percutaneous irradiation with implantable biofibre optic in vivo irradiation. The aim was to further investigate the effects of PBM on SCI in mice under new irradiation patterns and its potential mechanisms of action. PBM was administered to male mice with clamped SCI for four consecutive weeks and significantly promoted the recovery of motor function in mice. Analysis of the macrophage phenotypes in the epicentre of the SCI in mice showed that PBM mainly inhibited the neurotoxic activation of macrophages in the SCI area and reduced the secretion of inflammatory factors such as IL-1α and IL-6; PBM had no effect on M2 macrophages. Immediately afterwards, we constructed in vitro models of the inflammatory polarization of macrophages and PBM intervention. We found that PBM attenuated the neurotoxicity of M1 macrophages on VSC 4.1 motor neurons and dorsal root ganglion (DRG) neurons. The effects of PBM on neurotoxic macrophages and the possible mechanisms of action were analysed using RNA sequencing (RNA-seq), which confirmed that the main role of PBM was to modulate the inflammatory response and immune system processes. Analysis of the differentially expressed genes (DEGs) associated with the inflammatory response showed that PBM had the most significant regulatory effects on genes such as interleukin (IL)-1α, IL-6, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) and had obvious inhibitory effects on inflammation-related Notch1 and hypoxia-inducible factor-1α (HIF-1α) pathway genes. RNA-seq analysis of the effect of PBM on gene expression in resting-state macrophages and M2 macrophages did not show significant differences (data not shown). In conclusion, PBM promoted better motor recovery after SCI in mice by inhibiting the neurotoxic polarization of macrophages and the release of inflammatory mediators by acting on the Notch1-HIF-1α/NF-κB Signalling Pathway.

Photobiomodulation inhibits the activation of neurotoxic microglia and astrocytes by inhibiting Lcn2/JAK2-STAT3 crosstalk after spinal cord injury in male rats.

BACKGROUND: Neurotoxic microglia and astrocytes begin to activate and participate in pathological processes after spinal cord injury (SCI), subsequently causing severe secondary damage and affecting tissue repair. We have previously reported that photobiomodulation (PBM) can promote functional recovery by reducing neuroinflammation after SCI, but little is known about the underlying mechanism. Therefore, we aimed to investigate whether PBM ameliorates neuroinflammation by modulating the activation of microglia and astrocytes after SCI. METHODS: Male Sprague-Dawley rats were randomly divided into three groups: a sham control group, an SCI + vehicle group and an SCI + PBM group. PBM was performed for two consecutive weeks after clip-compression SCI models were established. The activation of neurotoxic microglia and astrocytes, the level of tissue apoptosis, the number of motor neurons and the recovery of motor function were evaluated at different days post-injury (1, 3, 7, 14, and 28 days post-injury, dpi). Lipocalin 2 (Lcn2) and Janus kinase-2 (JAK2)-signal transducer and activator of transcription-3 (STAT3) signaling were regarded as potential targets by which PBM affected neurotoxic microglia and astrocytes. In in vitro experiments, primary microglia and astrocytes were irradiated with PBM and cotreated with cucurbitacin I (a JAK2-STAT3 pathway inhibitor), an adenovirus (shRNA-Lcn2) and recombinant Lcn2 protein. RESULTS: PBM promoted the recovery of motor function, inhibited the activation of neurotoxic microglia and astrocytes, alleviated neuroinflammation and tissue apoptosis, and increased the number of neurons retained after SCI. The upregulation of Lcn2 and the activation of the JAK2-STAT3 pathway after SCI were suppressed by PBM. In vitro experiments also showed that Lcn2 and JAK2-STAT3 were mutually promoted and that PBM interfered with this interaction, inhibiting the activation of microglia and astrocytes. CONCLUSION: Lcn2/JAK2-STAT3 crosstalk is involved in the activation of neurotoxic microglia and astrocytes after SCI, and this process can be suppressed by PBM.

Photobiomodulation Promotes Repair Following Spinal Cord Injury by Regulating the Transformation of A1/A2 Reactive Astrocytes.

After spinal cord injury (SCI), reactive astrocytes can be classified into two distinctive phenotypes according to their different functions: neurotoxic (A1) astrocytes and neuroprotective (A2) astrocytes. Our previous studies proved that photobiomodulation (PBM) can promote motor function recovery and improve tissue repair after SCI, but little is known about the underlying mechanism. Therefore, we aimed to investigate whether PBM contributes to repair after SCI by regulating the activation of astrocytes. Male rats subjected to clip-compression SCI were treated with PBM for two consecutive weeks, and the results showed that recovery of motor function was improved, the lesion cavity size was reduced, and the number of neurons retained was increased. We determined the time course of A1/A2 astrocyte activation after SCI by RNA sequencing (RNA-Seq) and verified that PBM inhibited A1 astrocyte activation and promoted A2 astrocyte activation at 7 days postinjury (dpi) and 14 dpi. Subsequently, potential signaling pathways related to A1/A2 astrocyte activation were identified by GO function analysis and KEGG pathway analysis and then studied in animal experiments and preliminarily analyzed in cultured astrocytes. Next, we observed that the expression of basic fibroblast growth factor (bFGF) and transforming growth factor-ß (TGF-ß) was upregulated by PBM and that both factors contributed to the transformation of A1/A2 astrocytes in a dose-dependent manner. Finally, we found that PBM reduced the neurotoxicity of A1 astrocytes to dorsal root ganglion (DRG) neurons. In conclusion, PBM can promote better recovery after SCI, which may be related to the transformation of A1/A2 reactive astrocytes.

RIP2 knockdown inhibits cartilage degradation and oxidative stress in IL-1ß-treated chondrocytes via regulating TRAF3 and inhibiting p38 MAPK pathway.

Receptor-interacting protein 2 (RIP2) is a key mediator implicated in multiple cellular processes, and its dysregulation has been recently reported in colitis, asthma and other inflammatory diseases. However, the effects of RIP2 on osteoarthritis (OA) and the underlying mechanisms remain unclear. In this study, we found that RIP2 expression was upregulated in human articular cartilage tissues with OA and interleukin-1ß (IL-1ß)-treated chondrocytes. Knockdown of RIP2 inhibited IL-1ß-induced extracellular matrix (ECM) and oxidative stress. Moreover, knockdown of TRAF3 reversed the effects of RIP2 silencing on cartilage degradation and oxidative stress in IL-1ß-induced chondrocytes. In addition, p38 mitogen-activated protein kinase (MAPK) activator dehydrocorydalmine chloride (Dc) also reversed the effects of RIP2 silencing on IL-1ß-induced chondrocytes. Taken together, our data reveal that RIP2 knockdown inhibits cartilage degradation and oxidative stress in IL-1ß-treated chondrocytes by regulating TRAF3 expression and p38 MAPK pathway activation.

A novel thiazolidinediones ATZD2 rescues memory deficits in a rat model of type 2 diabetes through antioxidant and antiinflammation.

Type 2 diabetes (T2DM) has been associated with learning and memory impairment; however, drugs for diabetes could not prevent the development of cognitive decline in T2DM patients. In the present study, compounds derived from thiazolidinediones (TZD), a PPAR-γ agonist, were synthesized by conjuncting the alkyl-substituted benzimidazole group to TZD group (ATZDs). Based on the in vitro evaluation, the neuroprotection of ATZD2 was further investigated using a streptozotocin-induced T2DM rat model. Pharmacokinetic study showed that ATZD2 could pass the blood-brain barrier (BBB) while the rosiglitazone (RSG, the precursor compound of ATZD2) not. Administration of ATZD2 significantly promoted the survival rate and attenuated fasting blood glucose (FBG) levels as compared to RSG treatment in T2DM rats. Furthermore, ATZD2 treatment ameliorated the impairment of learning and memory by Morris water maze test. The beneficial effects of ATZD2 were associated with the down-regulation of hypoxia induced factor-1α, aldose reductase, and Bax expression which are related to T2DM pathology. ATZD2 treatment also attenuated the expression of inflammatory cytokines and restored the balance of redox in the diabetic hippocampus. These effects were more potent as compared with that of RSG at the same dose. The data indicate that ATZD2 may be a potent agent for the treatment of cognitive dysfunction in T2DM.