Tauroursodeoxycholic acid alleviates secondary injury in spinal cord injury mice by reducing oxidative stress, apoptosis, and inflammatory response

PTX promotes breast cancer migration and invasion by recruiting ATF4 to upregulate FGF19

BACKGROUND

Widely-spread among women, breast cancer is a malignancy with fatalities, and chemotherapy is a vital treatment option for it. Recent studies have underscored the potential of chemotherapeutic agents such as paclitaxel, adriamycin, cyclophosphamide, and gemcitabine, among others, in facilitating tumor metastasis, with paclitaxel being extensively researched in this context. The molecular mechanism of these genes and their potential relevance to breast cancer is noteworthy.

METHOD

Clinical tissue specimens were used to analyze the expression and clinical significance of FGF19 or P-FGFR4 in patients with breast cancer before and after chemotherapy. qRT-PCR, ELISA, immunofluorescence and Western blotting were used to detect the expression level of FGF19 in breast cancer cells. The biological impacts of paclitaxel, FGF19, and ATF4 on breast cancer cells were assessed through CCK8, Transwell, and Western blot assays. The expression of ATF4 in breast cancer cells was determined through database analysis, Western blot analysis, qRT-PCR, and immunofluorescence. The direct interaction between FGF19 and ATF4 was confirmed by a luciferase assay, and Western blotting was used to assess the levels of key proteins in the stress response pathway. To confirm the effects of PTX and FGF19 in vivo, we established a lung metastasis model in nude mice.

RESULTS

FGF19 expression was increased in breast cancer patients after chemotherapy. Paclitaxel can boost the migration and invasion of breast cancer cells, accompanied by an increase in FGF19 expression. ATF4 might be involved in facilitating the enhancing effect of FGF19 on breast cancer cell migration. Finally, stimulation during paclitaxel treatment could trigger a stress response, influencing the expression of FGF19 and the migration of breast cancer cells.

CONCLUSION

These data suggest that paclitaxel regulates FGF19 expression through ATF4 and thus promotes breast cancer cell migration and invasion.

Phillygenin inhibits neuroinflammation and promotes functional recovery after spinal cord injury via TLR4 inhibition of the NF-κB signaling pathway

Background

Spinal cord injuries (SCIs) trigger a cascade of detrimental processes, encompassing neuroinflammation and oxidative stress (OS), ultimately leading to neuronal damage. Phillygenin (PHI), isolated from forsythia, is used in a number of biomedical applications, and is known to exhibit anti-neuroinflammation activity. In this study, we investigated the role and mechanistic ability of PHI in the activation of microglia-mediated neuroinflammation and subsequent neuronal apoptosis following SCI.

Methods

A rat model of SCI was used to investigate the impact of PHI on inflammation, axonal regeneration, neuronal apoptosis, and the restoration of motor function. In vitro, neuroinflammation models were induced by stimulating microglia with lipopolysaccharide (LPS); then, we investigated the influence of PHI on pro-inflammatory mediator release in LPS-treated microglia along with the underlying mechanisms. Finally, we established a co-culture system, featuring microglia and VSC 4.1 cells, to investigate the role of PHI in the activation of microglia-mediated neuronal apoptosis.

Results

In vivo, PHI significantly inhibited the inflammatory response and neuronal apoptosis while enhancing axonal regeneration and improving motor function recovery. In vitro, PHI inhibited the release of inflammation-related factors from polarized BV2 cells in a dose-dependent manner. The online Swiss Target Prediction database predicted that toll-like receptor 4 (TLR4) was the target protein for PHI. In addition, Molecular Operating Environment software was used to perform molecular docking for PHI with the TLR4 protein; this resulted in a binding energy interaction of -6.7 kcal/mol. PHI inhibited microglia-mediated neuroinflammation, the production of reactive oxygen species (ROS), and activity of the NF-κb signaling pathway. PHI also increased mitochondrial membrane potential (MMP) in VSC 4.1 neuronal cells. In BV2 cells, PHI attenuated the overexpression of TLR4-induced microglial polarization and significantly suppressed the release of inflammatory cytokines.

Conclusion

PHI ameliorated SCI-induced neuroinflammation by modulating the TLR4/MYD88/NF-κB signaling pathway. PHI has the potential to be administered as a treatment for SCI and represents a novel candidate drug for addressing neuroinflammation mediated by microglial cells.

The translational potential of this article

We demonstrated that PHI is a potential drug candidate for the therapeutic management of SCI with promising developmental and translational applications.

The effects of hyaluronan and proteoglycan link protein 1 (HAPLN1) in ameliorating spinal cord injury mediated by Nrf2

Excessive inflammatory response and oxidative stress (OS) play an important role in the pathogenesis of spinal cord injury (SCI). Balance of inflammation and prevention of OS have been considered an effective strategy for the treatment of SCI. Hyaluronan and proteoglycan link protein 1 (HAPLN1), also known as cartilage link protein, has displayed a wide range of biological and physiological functions in different types of tissues and cells. However, whether HAPLN1 regulates inflammation and OS during SCI is unknown. Therefore, we aimed to examine whether HAPLN1 can have a protective effect on SCI. In this study, both in vitro and in vivo SCI models were established. Nissl staining and terminal deoxynucleotidyl transferase dUTP nick end labeling staining assays were used. Western blotting and enzyme-linked immunosorbent assay were employed to assess the expression of proteins. Our results demonstrate that the administration of HAPLN1 promoted the recovery of motor neurons after SCI by increasing the Basso mouse scale score, increasing the numbers of motor neurons, and preventing apoptosis of spinal cord cells. Additionally, HAPLN1 mitigated OS in spinal cord tissue after SCI by increasing the content of superoxide dismutase SOD and the activity of glutathione peroxidase but reducing the levels of malondialdehyde. Importantly, we found that HAPLN1 stimulated the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway and stimulated the expression of heme oxygenase-1 and nicotinamide adenine dinucleotide phosphate quinone oxidoreductase-1, which mediated the attenuation of HAPLN1 in activation of the NOD-like receptor protein 3 (NLRP3) inflammasome by reducing the levels of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, and interleukin-1β. Correspondingly, in vitro experiments show that the presence of HAPLN1 suppressed the NLRP3 inflammasome and prevented cell injury against H2O2 in PC12 cells. These effects were mediated by the Nrf2/ARE pathway, and inhibition of Nrf2 with ML385 abolished the beneficial effects of HAPLN1. Based on these findings, we conclude that HAPLN1 inhibits the NLRP3 inflammasome through the stimulation of the Nrf2/ARE pathway, thereby suppressing neuroinflammation, enhancing motor neuronal survival, and improving the recovery of nerve function after SCI.

Tauroursodeoxycholic Acid Inhibited Apoptosis and Oxidative Stress in H2O2-Induced BMSC Death via Modulating the Nrf-2 Signaling Pathway: the Therapeutic Implications in a Rat Model of Spinal Cord Injury

Spinal cord injury (SCI) is a prevalent and significant injury to the central nervous system, resulting in severe consequences. This injury is characterized by motor, sensory, and excretory dysfunctions below the affected spinal segment. Transplantation of bone marrow mesenchymal stem cells (BMSCs) has emerged as a potential treatment for SCI. However, the low survival as well as the differentiation rates of BMSCs within the spinal cord microenvironment significantly limit their therapeutic efficiency. Tauroursodeoxycholic acid (TUDCA), an active ingredient found in bear bile, has demonstrated its neuroprotective, antioxidant, and antiapoptotic effects on SCI. Thus, the present study was aimed to study the possible benefits of combining TUDCA with BMSC transplantation using an animal model of SCI. The results showed that TUDCA significantly enhanced BMSC viability and reduced apoptosis (assessed by Annexin V-FITC, TUNEL, Bax, Bcl-2, and Caspase-3) as well as oxidative stress (assessed by ROS, GSH, SOD, and MDA) both in vitro and in vivo. Additionally, TUDCA accelerated tissue regeneration (assessed by HE, Nissl, MAP2, MBP, TUJ1, and GFAP) and improved functional recovery (assessed by BBB score) following BMSC transplantation in SCI. These effects were mediated via the Nrf-2 signaling pathway, as evidenced by the upregulation of Nrf-2, NQO-1, and HO-1 expression levels. Overall, these results indicate that TUDCA could serve as a valuable adjunct to BMSC transplantation therapy for SCI, potentially enhancing its therapeutic efficacy.

Injectable, Electroconductive, Free Radical Scavenging Silk Fibroin/Black Phosphorus/Glycyrrhizic Acid Nanocomposite Hydrogel for Enhancing Spinal Cord Repair

Spinal cord injury (SCI) often leads to a severe permanent disability. A poor inflammatory microenvironment and nerve electric signal conduction block are the main reasons for difficulty in spinal cord nerve regeneration. In this study, black phosphorus (BP) and glycyrrhizic acid (GA) are integrated into methacrylate-modified silk fibroin (SF) to construct a bifunctional injectable hydrogel (SF/BP/GA) with appropriate conductivity and the ability to inhibit inflammation to promote neuronal regeneration after SCI. This work discovers that the SF/BP/GA hydrogel can reduce the oxidative damage mediated by oxygen free radicals, promote the polarization of macrophages toward the anti-inflammatory M2 phenotype, reduce the expression of inflammatory factors, and improve the inflammatory microenvironment. Moreover, it induces neural stem cell (NSC) differentiation and neurosphere formation, restores signal conduction at the SCI site in vivo, and ameliorates motor function in mice with spinal cord hemisection, revealing a significant neural repair effect. An injectable, electroconductive, free-radical-scavenging hydrogel is a promising therapeutic strategy for SCI repair.

Tauroursodeoxycholic Acid (TUDCA) Relieves Streptozotocin (STZ)-Induced Diabetic Rat Model via Modulation of Lipotoxicity, Oxidative Stress, Inflammation, and Apoptosis

Tauroursodeoxycholic acid (TUDCA) is approved for the treatment of liver diseases. However, the antihyperglycemic effects/mechanisms of TUDCA are still less clear. The present study aimed to evaluate the antidiabetic action of TUDCA in streptozotocin (STZ)-induced type 2 diabetes mellitus (T2DM) in rats. Fifteen adult Wistar albino male rats were randomly divided into three groups (n = five in each): control, diabetic (STZ), and STZ+TUDCA. The results showed that TUDCA treatment significantly reduced blood glucose, HbA1c%, and HOMA-IR as well as elevated the insulin levels in diabetic rats. TUDCA therapy increased the incretin GLP-1 concentrations, decreased serum ceramide synthase (CS), improved the serum lipid profile, and restored the glycogen content in the liver and skeletal muscles. Furthermore, serum inflammatory parameters (such as TNF-α, IL-6, IL-1ß, and PGE-2) were substantially reduced with TUDCA treatment. In the pancreas, STZ+TUDCA-treated rats underwent an obvious enhancement of enzymatic (CAT and SOD) and non-enzymatic (GSH) antioxidant defense systems and a marked decrease in markers of the lipid peroxidation rate (MDA) and nitrosative stress (NO) compared to STZ-alone. At the molecular level, TUDCA decreased the pancreatic mRNA levels of iNOS and apoptotic-related factors (p53 and caspase-3). In conclusion, TUDCA may be useful for diabetes management and could be able to counteract diabetic disorders via anti-hyperlipidemic, antioxidant, anti-inflammatory, and anti-apoptotic actions.

Tauroursodeoxycholic Acid Reverses Dextran Sulfate Sodium-Induced Colitis in Mice via Modulation of Intestinal Barrier Dysfunction and Microbiome Dysregulation

Ulcerative colitis (UC) is an immune-mediated inflammatory disease that can lead to persistent damage and even cancer without any intervention. Conventional treatments can alleviate UC symptoms but are costly and cause various side effects. Tauroursodeoxycholic acid (TUDCA), a secondary bile acid derivative, possesses anti-inflammatory and cytoprotective properties for various diseases, but its potential therapeutic benefits in UC have not been fully explored. Mice were subjected to colitis induction using 3% dextran sulfate sodium (DSS). The therapeutic effect of TUDCA was evaluated by body weight loss, disease activity index (DAI), colon length, and spleen weight ratio. Tissue pathology was assessed using H&E staining, while the levels of pro-inflammatory and anti-inflammatory cytokines in colonic tissue were quantified via ELISA. Tight junction proteins were detected by immunoblotting and intestinal permeability was assessed using fluorescein isothiocyanate (FITC)-dextran. Moreover, the gut microbiota was profiled using high-throughput sequencing of the 16S rDNA gene. TUDCA alleviated the colitis in mice, involving reduced DAI, attenuated colon and spleen enlargement, ameliorated histopathological lesions, and normalized levels of pro-inflammatory and anti-inflammatory cytokines. Furthermore, TUDCA treatment inhibited the downregulation of intestinal barrier proteins, including zonula occludens-1 and occludin, thus reducing intestinal permeability. The analysis of gut microbiota suggested that TUDCA modulated the dysbiosis in mice with colitis, especially for the remarkable rise in Akkermansia TUDCA exerted a therapeutic efficacy in DSS-induced colitis by reducing intestinal inflammation, protecting intestinal barrier integrity, and restoring gut microbiota balance. SIGNIFICANCE STATEMENT: This study demonstrates the potential therapeutic benefits of Tauroursodeoxycholic acid (TUDCA) in ulcerative colitis. TUDCA effectively alleviated colitis symptoms in mice, including reducing inflammation, restoring intestinal barrier integrity and the dysbiosis of gut microbiota. This work highlights the promising role of TUDCA as a potentially alternative treatment, offering new insights into managing this debilitating condition.

Transplantation of MiR-28-5p-Modified BMSCs Promotes Functional Recovery After Spinal Cord Injury

Traumatic spinal cord injury (TSCI) is a prevalent central nervous system condition that imposes a significant burden on both families and society, affecting more than 2 million people worldwide. Recently, there has been increasing interest in bone marrow mesenchymal stem cell (BMSC) transplantation as a promising treatment for spinal cord injury (SCI) due to their accessibility and low immunogenicity. However, the mere transplantation of BMSCs has limited capacity to directly participate in the repair of host spinal cord nerve function. MiR-28-5p, identified as a key differentially expressed miRNA in spinal cord ischemia-reperfusion injury, exhibits differential expression and regulation in various neurological diseases. Nevertheless, its involvement in this process and its specific regulatory mechanisms in SCI remain unclear. Therefore, this study aimed to investigate the potential mechanisms through which miR-28-5p promotes the neuronal differentiation of BMSCs both in vivo and in vitro. Our results indicate that miR-28-5p may directly target Notch1, thereby facilitating the neuronal differentiation of BMSCs in vitro. Furthermore, the transplantation of lentivirus-mediated miR-28-5p-overexpressed BMSCs into SCI rats effectively improved footprint tests and Basso, Beattie, and Bresnahan (BBB) scores, ameliorated histological morphology (hematoxylin-eosin [HE] and Nissl staining), promoted axonal regeneration (MAP2 and growth-associated protein 43 [GAP43]), and facilitated axonal remyelination (myelin basic protein [MBP]). These findings may suggest that miR-28-5p-modified BMSCs could serve as a therapeutic target to enhance the behavioral and neurological recovery of SCI rats.

Propofol Ameliorates Spinal Cord Injury Process by Mediating miR-672-3p/TNIP2 Axis

Propofol has been found to have a protective effect against spinal cord injury (SCI). However, the underlying molecular mechanism of propofol regulating SCI process remains unclear. In this study, lipopolysaccharide (LPS)-induced PC12 cells were used to build SCI cell models. Cell viability and apoptosis were determined by cell counting kit 8 assay, flow cytometry, and caspase-3 activity detection. The protein levels of apoptosis-related markers and TNFAIP3 interacting protein 2 (TNIP2) were assessed using western blot analysis, and the levels of inflammatory factors were detected using ELISA. Cell oxidative stress was evaluated by measuring malondialdehyde (MDA) and reactive oxygen species (ROS) levels. The expression of microRNA (miR)-672-3p was examined by quantitative real-time PCR. SCI rat models were constructed to assess the effect of propofol in vivo. We found that propofol treatment promoted viability, while inhibited apoptosis, inflammation and oxidative stress of LPS-induced PC12 cells. Propofol decreased miR-672-3p expression, and miR-672-3p overexpression eliminated the inhibiting effect of propofol on LPS-induced PC12 cell injury. Besides, miR-672-3p targeted TNIP2, and TNIP2 knockdown reversed the protective effect of miR-672-3p inhibitor or propofol against LPS-induced PC12 cell injury. In vivo experiments, propofol treatment enhanced the motor function recovery and inhibited apoptosis of SCI rat models. In conclusion, propofol increased TNIP2 level by reducing miR-672-3p expression, thereby alleviating LPS-induced PC12 cell injury and improving the motor function of SCI rat models.

The compensatory increase of Gli-similar 3 inhibited neuronal apoptosis through regulating Mps one binder kinase activator 1b (MOB1b): a possible strategy for the functional recovery after spinal cord injury

Spinal cord injury (SCI) is a devastating disease characterized by neuronal apoptosis. Gli-similar 3 (GLIS3), a transcriptional factor, was involved in cell apoptosis and associated with the transcription of downstream target genes related to neuronal function. However, the function of GLIS3 in SCI remains unknown. Therefore, we used the mouse model of SCI to explore the role of GLIS3 in SCI. The results showed that GLIS3 expression was significantly increased in spinal cord tissues of SCI mice, and GLIS3 overexpression promoted the functional recovery, reserved histological changes, and inhibited neuronal apoptosis after SCI. Through online tools, the potential target genes of GLIS3 were analyzed and we found that Mps one binder kinase activator 1b (Mob1b) had a strong association with SCI among these genes. MOB1b is a core component of Hippo signaling pathway, which was reported to inhibit cell apoptosis. MOB1b expression was significantly increased in mice at 7 days post-SCI and GLIS3 overexpression further increased its expression. Dual-luciferase reporter assay revealed that GLIS3 bound to the promoter of Mob1b and promoted its transcription. In conclusion, our findings reveal that the compensatory increase of GLIS3 promotes functional recovery after SCI through inhibiting neuronal apoptosis by transcriptionally regulating MOB1b. Our study provides a novel target for functional recovery after SCI.

Screening and evaluation of metabolites binding PRAS40 from Erxian decoction used to treat spinal cord injury

Objective: The PRAS40 is an essential inhibitory subunit of the mTORC1 complex, which regulates autophagy. It has been suggested that Erxian Decoction (EXD) could treat spinal cord injury (SCI) via the autophagy pathway. However, the mechanism of whether EXD acts through PRAS40 remains unclear. Methods: With the help of immobilized PRAS40, isothermal titration calorimetry (ITC) and molecular docking, the bioactive metabolites in the EXD were screened. To establish in vitro SCI models, PC12 cells were exposed to hydrogen peroxide (H2O2) and then treated with the identified EXD substances. Furthermore, Western blot assay was carried out to identify potential molecular mechanisms involved. For assessing the effect of metabolites in vivo, the SCI model rats were first pretreated with or without the metabolite and then subjected to the immunohistochemistry (IHC) staining, Basso, Beattie & Bresnahan (BBB) locomotor rating scale, and H&E staining. Results: The immobilized PRAS40 isolated indole, 4-nitrophenol, terephthalic acid, palmatine, sinapinaldehyde, and 3-chloroaniline as the potential ligands binding to PRAS40. Furthermore, the association constants of palmatine and indole as 2.84 × 106 M-1 and 3.82 × 105 M-1 were elucidated via ITC due to the drug-like properties of these two metabolites. Molecular docking results also further demonstrated the mechanism of palmatine binding to PRAS40. Western blot analysis of PC12 cells demonstrated that palmatine inhibited the expression of p-mTOR by binding to PRAS40, activating the autophagic flux by markedly increasing LC3. The injection of palmatine (10μM and 20 μM) indicated notably increased BBB scores in the SCI rat model. Additionally, a dose-dependent increase in LC3 was observed by IHC staining. Conclusion: This research proved that EXD comprises PRAS40 antagonists, and the identified metabolite, palmatine, could potentially treat SCI by activating the autophagic flux.

HGF secreted by hUC-MSCs mitigates neuronal apoptosis to repair the injured spinal cord via phosphorylation of Akt/FoxO3a pathway

Spinal cord injury (SCI) can cause severe and permanent neurological damage, and neuronal apoptosis could inhibit functional recovery of damaged spinal cord greatly. Human umbilical cord mesenchymal stem cells (hUC-MSCs) have great potential to repair SCI because of a series of advantages, including inhibition of neuronal apoptosis and multiple differentiation. The former may play an important role. However, the detailed regulatory mechanism associated with the inhibition of neuronal apoptosis after hUC-MSCs administration has not been elucidated. In this study, proteomics analysis of precious human cerebrospinal fluid (CSF) samples collected from SCI subjects receiving hUC-MSCs delivery indicated that hepatocyte growth factor (HGF) is largely involved in SCI repair. Furthermore, overexpression of HGF derived from hUC-MSCs could decrease reactive oxygen species to prevent neuron apoptosis to the maximum, and thus lead to significant recovery of spinal cord dysfunction. Moreover, HGF could promote phosphorylation of Akt/FoxO3a pathway to decrease reactive oxygen species to reduce neuron apoptosis. For the first time, our research revealed that HGF secreted by hUC-MSCs inhibits neuron apoptosis by phosphorylation of Akt/FoxO3a to repair SCI. This study provides important clues associated with drug selection for the effective treatment of SCI in humans.

Resveratrol can improve spinal cord injury by activating Nrf2/HO-1 signaling pathway

Spinal cord injury (SCI) often induces severe sensory and motor dysfunction. Oxidative stress is an important pathophysiological process of secondary SCI, and its inhibition could facilitate the alleviation of the injury. Resveratrol is a natural plant polyphenol compound that has significant antioxidant and anti-inflammatory effects. It can inhibit oxidative stress by activating the Nrf2/HO-1 signal pathway. In this report, we analyze the antioxidant effect of resveratrol in SCI, clarify the specific mechanism of action and provide a theoretical basis for the clinical employment of resveratrol for SCI.

Hydrogel and Nanomedicine-Based Multimodal Therapeutic Strategies for Spinal Cord Injury

Spinal cord injury (SCI) is a severe neurodegenerative disease caused by mechanical and biological factors, manifesting as a loss of motor and sensory functions. Inhibition of injury expansion and even reversal of injury in the acute damage stage of SCI are important strategies for treating this disease. Hydrogels and nanoparticle (NP)-based drugs are the most effective, widely studied, and clinically valuable therapeutic strategies in the field of repair and regeneration. Hydrogels are 3D flow structures that fill the pathological gaps in SCI and provide a microenvironment similar to that of the spinal cord extracellular matrix for nerve cell regeneration. NP-based drugs can easily penetrate the blood-spinal cord barrier, target SCI lesions, and are noninvasive. Hydrogels and NPs as drug carriers can be loaded with various drugs and biological therapeutic factors for slow release in SCI lesions. They help drugs function more efficiently by exerting anti-inflammatory, antioxidant, and nerve regeneration effects to promote the recovery of neurological function. In this review, the use of hydrogels and NPs as drug carriers and the role of both in the repair of SCI are discussed to provide a multimodal strategic reference for nerve repair and regeneration after SCI.

MiR-203a-3p attenuates apoptosis and pyroptosis of chondrocytes by regulating the MYD88/NF-κB pathway to alleviate osteoarthritis progression

BACKGROUND

Osteoarthritis (OA) is a degenerative joint disease that imposes a significant socioeconomic burden worldwide. Our previous studies revealed a down-regulation of miR-203a-3p in the knee tissues of OA patients. However, the underlying mechanism through which miR-203a-3p mediates the pathological process of OA remains unknown. Thus, we aimed to determine the effects of miR-203a-3p in the progression of OA.

METHODS

Rat primary chondrocytes were stimulated with 10 μg/mL lipopolysaccharide (LPS) for 24 hours, followed by transfection with 50 nM miR-203a-3p mimic, inhibitor, and siRNA for MYD88 or consistent negative controls for 48 hours. To evaluate the effects of miR-203a-3p on cartilage matrix degradation, oxidative stress, apoptosis, and pyroptosis in chondrocytes, various techniques such as immunofluorescence staining, biochemical analysis, Western blotting, and the TUNEL staining were utilized. In the rat OA model, all rats were randomly divided into four groups: Sham, OA, OA+Agomir negative control (NC), and OA+Agomir. They received intra-articular injections of 25 nmol miR-203a-3p agomir, agomir NC, or normal saline twice a week for the duration of 8 weeks after OA induction. Immunofluorescence staining was performed to evaluate the effects of miR-203a-3p on cartilage matrix degradation in rats.

RESULTS

MiR-203a-3p was down-regulated in LPS-treated rat chondrocytes and OA cartilage, and directly targeted MYD88. Moreover, miR-203a-3p significantly inhibited LPS-induced cartilage matrix degradation, oxidative stress, apoptosis, and pyroptosis of chondrocytes via targeting MYD88. Mechanistically, miR-203a-3p exerted protective effects via the inhibition of the MYD88/NF-κB pathway. In the rat OA model, intra-articular injections of miR-203a-3p agomir also significantly inhibited cartilage matrix degradation, thereby alleviating OA progression. Furthermore, the miR-203a-3p agomir-treated arthritic rat dramatically exhibited better articular tissue morphology and lower OARSI scores.

CONCLUSIONS

MiR-203a-3p plays a role in alleviating the progression of OA by regulating the MYD88/NF-κB pathway, thereby inhibiting cartilage matrix degradation, oxidative stress, apoptosis, and pyroptosis of chondrocytes. It highlights the potential significance of miR-203a-3p as an important regulator of OA.

Formononetin ameliorates the LPS-induced inflammatory response and apoptosis of neuronal cells via NF-κB/NLRP3 signaling pathway

The objective of this study was to investigate the impact of formononetin on cellular apoptosis and inflammatory responses following spinal cord injury (SCI), as well as the underlying mechanisms involved. In this study, PC12 cells were treated with lipopolysaccharide (LPS) and different concentrations of Formononetin (FT) (50 μM, 100 μM, 200 μM). To confirm the effect of nuclear factor-κB (NF-κB)/NLR family pyrin domain containing 3 (NLRP3) signaling pathways, the cells in the phorbol-12-myristate-13-acetate (PMA) group were treated with 0.1 μmol/L PMA (NF-κB/NLRP3 signaling pathway activators). The lactate dehydrogenase (LDH) concentration and cell viability, proliferating cell nuclear antigen (PCNA) fluorescence intensity, and cell apoptosis were determined using an LDH kit, Cell Counting Kit-8 (CCK-8), immunofluorescence, and flow cytometry assays, respectively. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-16 (IL-6) expression levels were detected by quantitative ELISA assay. The expression of proteins related to the NF-κB/NLRP3 signaling pathway was detected by western blotting. Our results showed that LPS increased LDH levels in PC12 cells, suggesting that inflammation caused PC12 cell damage. However, the PC12 cell damage was decreased by methylprednisolone. Formononetin promotes cell survival and proliferation, and prevents apoptosis in a concentration-dependent manner. Formononetin reduced the TNF-α, IL-1β, and IL-6 levels in the LPS-treated model. Moreover, formononetin decreased the levels of p-p65 NF-κB and NLRP3 in PC12 cells. We conclude that formononetin ameliorated the inflammatory response and apoptosis in LPS-induced inflammatory injury in neuronal cells via the NF-κB/NLRP3 signaling pathway.

LncRNA TSIX aggravates spinal cord injury by regulating the PI3K/AKT pathway via the miR-532-3p/DDOST axis

Long noncoding RNA (lncRNA)-X-inactive-specific transcript (TSIX) expression is upregulated in spinal cord tissues following spinal cord injury (SCI). However, the role of lncRNA-TSIX in SCI remains elusive. SCI animal model was established using C57BL/6 mice. LncRNA TSIX and miR-532-3p expression were determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Apoptosis, cell proliferation, and migration were evaluated by transferase dUTP nick end labeling staining, CCK-8, and Transwell assays, respectively. The interaction of miR-532-3p with lncRNA TSIX and DDOST was explored via a dual-luciferase reporter system. Hematoxylin-eosin staining and the Basso, Beattie, and Bresnahan locomotor rating (BBB) scale were performed to investigate SCI progression. The expression of the lncRNA TSIX was found to be significantly upregulated in the serum of SCI patients and spinal cord tissues of SCI mice. The overexpression of lncRNA TSIX enhanced spinal cord neural stem cell (SC-NSC) proliferation and migration in vitro while inhibiting apoptosis and inflammatory cell infiltration in vivo. Moreover, lncRNA TSIX acted as a molecular sponge for miR-532-3p, and the knockdown of miR-532-3p promoted proliferation and migration and inhibited apoptosis of SC-NSCs. Moreover, DDOST was found to be the downstream target of miR-532-3p, and DDOST overexpression showed a similar effect as miR-532-3p silencing on the proliferation, migration, and apoptosis of SC-NSCs. Furthermore, we found that lncRNA TSIX overexpression promoted the activation of the PI3K/AKT signaling pathway. LncRNA TSIX aggravates SCI by regulating the PI3K/AKT pathway via the miR-532-3p/DDOST axis, indicating potential applications for targeted therapy of SCI regeneration.

Deletion of Transferrin Receptor 1 in Parvalbumin Interneurons Induces a Hereditary Spastic Paraplegia-Like Phenotype

Hereditary spastic paraplegia (HSP) is a severe neurodegenerative movement disorder, the underlying pathophysiology of which remains poorly understood. Mounting evidence has suggested that iron homeostasis dysregulation can lead to motor function impairment. However, whether deficits in iron homeostasis are involved in the pathophysiology of HSP remains unknown. To address this knowledge gap, we focused on parvalbumin-positive (PV+) interneurons, a large category of inhibitory neurons in the central nervous system, which play a critical role in motor regulation. The PV+ interneuron-specific deletion of the gene encoding transferrin receptor 1 (TFR1), a key component of the neuronal iron uptake machinery, induced severe progressive motor deficits in both male and female mice. In addition, we observed skeletal muscle atrophy, axon degeneration in the spinal cord dorsal column, and alterations in the expression of HSP-related proteins in male mice with Tfr1 deletion in the PV+ interneurons. These phenotypes were highly consistent with the core clinical features of HSP cases. Furthermore, the effects on motor function induced by Tfr1 ablation in PV+ interneurons were mostly concentrated in the dorsal spinal cord; however, iron repletion partly rescued the motor defects and axon loss seen in both sexes of conditional Tfr1 mutant mice. Our study describes a new mouse model for mechanistic and therapeutic studies relating to HSP and provides novel insights into iron metabolism in spinal cord PV+ interneurons and its role in the regulation of motor functions.SIGNIFICANCE STATEMENT Iron is crucial for neuronal functioning. Mounting evidence suggests that iron homeostasis dysregulation can induce motor function deficits. Transferrin receptor 1 (TFR1) is thought to be the key component in neuronal iron uptake. We found that deletion of Tfr1 in parvalbumin-positive (PV+) interneurons in mice induced severe progressive motor deficits, skeletal muscle atrophy, axon degeneration in the spinal cord dorsal column, and alterations in the expression of hereditary spastic paraplegia (HSP)-related proteins. These phenotypes were highly consistent with the core clinical features of HSP cases and partly rescued by iron repletion. This study describes a new mouse model for the study of HSP and provides novel insights into iron metabolism in spinal cord PV+ interneurons.

Roles of bile acids signaling in neuromodulation under physiological and pathological conditions

Bile acids (BA) are important physiological molecules not only mediating nutrients absorption and metabolism in peripheral tissues, but exerting neuromodulation effect in the central nerve system (CNS). The catabolism of cholesterol to BA occurs predominantly in the liver by the classical and alternative pathways, or in the brain initiated by the neuronal-specific enzyme CYP46A1 mediated pathway. Circulating BA could cross the blood brain barrier (BBB) and reach the CNS through passive diffusion or BA transporters. Brain BA might trigger direct signal through activating membrane and nucleus receptors or affecting activation of neurotransmitter receptors. Peripheral BA may also provide the indirect signal to the CNS via farnesoid X receptor (FXR) dependent fibroblast growth factor 15/19 (FGF15/19) pathway or takeda G protein coupled receptor 5 (TGR5) dependent glucagon-like peptide-1 (GLP-1) pathway. Under pathological conditions, alterations in BA metabolites have been discovered as potential pathogenic contributors in multiple neurological disorders. Attractively, hydrophilic ursodeoxycholic acid (UDCA), especially tauroursodeoxycholic acid (TUDCA) can exert neuroprotective roles by attenuating neuroinflammation, apoptosis, oxidative or endoplasmic reticulum stress, which provides promising therapeutic effects for treatment of neurological diseases. This review summarizes recent findings highlighting the metabolism, crosstalk between brain and periphery, and neurological functions of BA to elucidate the important role of BA signaling in the brain under both physiological and pathological conditions.

Monotropein attenuates apoptosis and pyroptosis in chondrocytes and alleviates osteoarthritis progression in mice

BACKGROUND

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by loss of joint function, which seriously reduces the quality of life of the elderly and imposes a heavy socioeconomic burden worldwide. Monotropein (MON), the main active ingredient of Morinda officinalis F.C. How, has exhibited therapeutic effects in different disease models. However, its potential effects on chondrocytes in an arthritic model remain unclear. This study aimed to evaluate the effects of MON in chondrocytes and a mouse model of OA, and explore the potential mechanisms.

MATERIALS AND METHODS

Murine primary chondrocytes were pretreated with 10 ng/ml interleukin (IL)-1β for 24 h to establish an in vitro model of OA, and then treated with different concentrations of MON (0, 25, 50 and 100 μM) for 24 h. The proliferation of the chondrocytes was assayed using ethynyl-deoxyuridine (EdU) staining. Immunofluorescence staining, western blotting and TUNEL staining were performed to assess the effects of MON on cartilage matrix degradation, apoptosis and pyroptosis. The mouse model of OA was constructed by surgical destabilization of the medial meniscus (DMM), and the animals were randomly divided into the sham-operated, OA and OA + MON groups. Following OA induction, the mice were given intraarticular injection of 100 μM MON or equal volume of normal saline twice a week for 8 weeks. The effects of MON on cartilage matrix degradation, apoptosis and pyroptosis were assessed as indicated.

RESULTS

MON significantly accelerated the proliferation of chondrocytes, and inhibited cartilage matrix degradation, apoptosis and pyroptosis in the IL-1β-stimulated cells by blocking the nuclear factor-kappa B (NF-κB) signaling pathway. In the mouse model as well, MON treatment alleviated OA progression and promoted cartilage repair by inhibiting cartilage matrix degradation, and chondrocyte apoptosis and pyroptosis through the inactivation of the NF-κB signaling pathway. Furthermore, the MON-treated arthritic mice exhibited better articular tissue morphology and lower OARSI scores.

CONCLUSIONS

MON alleviated OA progression by inhibiting cartilage matrix degradation, and the apoptosis and pyroptosis of chondrocytes via NF-κB pathway inactivation, and is a promising alternative for the treatment of OA.

Bile Acids Induce Neurite Outgrowth in Nsc-34 Cells via TGR5 and a Distinct Transcriptional Profile

Increasing evidence supports a neuroprotective role for bile acids in major neurodegenerative disorders. We studied major human bile acids as signaling molecules for their two cellular receptors, farnesoid X receptor (FXR or NR1H4) and G protein-coupled bile acid receptor 1 (GPBAR1 or TGR5), as potential neurotrophic agents. Using quantitative image analysis, we found that 20 μM deoxycholic acid (DCA) could induce neurite outgrowth in NSC-34 cells that was comparable to the neurotrophic effects of the culture control 1 μM retinoic acid (RA), with lesser effects observed for chenodexoycholic acid (CDCA) at 20 μM, and similar though less robust neurite outgrowth in SH-SY5Y cells. Using chemical agonists and antagonists of FXR, LXR, and TGR5, we found that TGR5 agonism was comparable to DCA stimulation and stronger than RA, and that neither FXR nor liver X receptor (LXR) inhibition could block bile acid-induced neurite growth. RNA sequencing identified a core set of genes whose expression was regulated by DCA, CDCA, and RA. Our data suggest that bile acid signaling through TGR5 may be a targetable pathway to stimulate neurite outgrowth.

Experimental Treatments for Spinal Cord Injury: A Systematic Review and Meta-Analysis

Spinal cord injury (SCI) is characterized by a complex and prolonged injury process that exacerbates the damage induced by the primary injury and inhibits the potential for regeneration. SCI frequently results in the devastating loss of neurological functions and thus has serious consequences on patient quality of life. Current treatments are limited and focus on early interventions for the acute management of complications. Therefore, the development of novel treatments targeting ongoing injury processes is required to improve SCI outcomes. We aimed to systematically review studies published in the last 10 years that examined experimental treatments with neuroregenerative and neuroprotective capabilities for the improvement of SCI. We analyzed treatments from 44 studies that were identified through a systematic literature search using three databases: PubMed, Web of Science and EMBASE (searched through Ovid). We performed a meta-analysis for Basso-Beattie-Bresnahan (BBB) locomotion test data and collected immunohistochemistry results to demonstrate neuroregenerative and neuroprotective properties of the treatments, respectively. The two treatments that illustrated the most significant improvements in functional recovery using the BBB test were the combined use of tetrahedral framework nucleic acid (tFNA) with neural stem cells (NSCs) and Fortasyn® Connect (FC) supplementation. Both treatments also attenuated secondary injury processes as demonstrated through immunohistochemistry. Combined tFNA with NSCs and FC supplementation are promising treatments for the improvement of SCI as they both demonstrate neuroregenerative and neuroprotective properties. Further pre-clinical testing is required to validate and determine the long-term efficacies of these treatments for the improvement of SCI.

Andrographolide contributes to spinal cord injury repair via inhibition of apoptosis, oxidative stress and inflammation

Background: Spinal cord injury (SCI) is a common disorder of the central nervous system with considerable socio-economic burden. Andrographolide (Andro), the main active component of Andrographis paniculata, has exhibited neuroprotective effects in different models of neurological diseases. The aim of this study was to evaluate the neuroprotective effects of Andro against SCI and explore the related mechanisms.

Methods: SCI was induced in rats by the Allen method, and the modeled animals were randomly divided into sham-operated, SCI, SCI + normal saline (NS) and SCI + Andro groups. The rats were injected intraperitoneally with Andro (1 mg/kg) or the same volume of NS starting day one after the establishment of the SCI model for 28 consecutive days. Post-SCI tissue repair and functional recovery were evaluated by measuring the spinal cord water content, footprint tests, Basso-Beattie-Bresnahan (BBB) scores, hematoxylin-eosin (HE) staining and Nissl staining. Apoptosis, oxidative stress and inflammation, as well as axonal regeneration and remyelination were analyzed using suitable markers. The in vitro model of SCI was established by treating cortical neurons with H₂O₂. The effects of Andro on apoptosis, oxidative stress and inflammation were evaluated as indicated.

Results: Andro treatment significantly improved tissue repair and functional recovery after SCI by reducing apoptosis, oxidative stress and inflammation through the nuclear factor E2-related factor 2/heme oxygenase-1 (Nrf-2/HO-1) and nuclear factor-kappa B (NF-κB) signaling pathways. Furthermore, Andro treatment promoted M2 polarization of the microglial cells and contributed to axonal regeneration and remyelination to improve functional recovery after SCI. In addition, Andro also attenuated apoptosis, oxidative stress and inflammation in H₂O₂-stimulated cortical neurons in vitro.

Conclusion: Andro treatment alleviated SCI by reducing apoptosis, oxidative stress and inflammation in the injured tissues and cortical neurons, and promoted axonal regeneration and remyelination for functional recovery.

A bibliometric of research trends in acupuncture for spinal cord injury: Quantitative and qualitative analyses

Introduction

Spinal cord injury (SCI) is a severe disease of the central nervous system with a very high disability rate that seriously affects the daily life of patients. Acupuncture is one of the rehabilitation therapies that has shown significant efficacy in treating post-SCI complications such as motor disorders, neuropathic pain, and neurogenic bladder. Current studies have focused on the effectiveness and mechanisms of acupuncture for SCI, but no studies are available to analyze the bibliometrics of publications related to this area.

Methods

Publications related to acupuncture for SCI were retrieved from the Web of Science Core Collection for quantitative and qualitative analyses. The quantitative analysis was unfolded in the following six main areas: annual publications, countries, institutions, authors, sources, and keywords. The qualitative analysis section screened out publications with high annual citation rates and categorized them according to the study content.

Results

There were 213 relevant publications, more than half of which were journal articles. The number of publications showed a fluctuating upward trend. China and the United States were hub countries for related publications and had extensive cooperation with other countries. The most relevant author was Yuanshan Zeng from Sun Yat-sen University, China. The efficacy and mechanism of acupuncture for neuropathic pain after SCI was the first research hotspot in this field, and electroacupuncture was the most widely used technique. In the past 5 years, the mechanism of acupuncture to improve the local microenvironment of SCI and promote nerve regeneration had become a new research trend. At the same time, acupuncture had been gradually applied to various complications after SCI and in veterinary medicine.

Conclusion

The findings suggest that research on acupuncture for SCI is still flourishing, and more research on electroacupuncture for promoting nerve repair and regeneration after SCI will be available in the future.

Inhibition of Endoplasmic Reticulum Stress Improves Acetylcholine-Mediated Relaxation in the Aorta of Type-2 Diabetic Rats

Endoplasmic reticulum (ER) stress contributes to insulin resistance and macro- and microvascular complications associated with diabetes. This study aimed to evaluate the effect of ER stress inhibition on endothelial function in the aorta of type-2 diabetic rats. Type-2 diabetes was developed in male Sprague-Dawley rats using a high-fat diet and low-dose streptozotocin. Rat aortic tissues were harvested to study endothelial-dependent relaxation. The mechanisms for acetylcholine-mediated relaxation were investigated using pharmacological blockers, Western blotting, oxidative stress, and inflammatory markers. Acetylcholine-mediated relaxation was diminished in the aorta of diabetic rats compared to control rats; supplementation with TUDCA improved relaxation. In the aortas of control and diabetic rats receiving TUDCA, the relaxation was mediated via eNOS/PI3K/Akt, NAD(P)H, and the KATP channel. In diabetic rats, acetylcholine-mediated relaxation involved eNOS/PI3K/Akt and NAD(P)H, but not the KATP channel. The expression of ER stress markers was upregulated in the aorta of diabetic rats and reduced with TUDCA supplementation. The expression of eNOS and Akt were lower in diabetic rats but were upregulated after supplementation with TUDCA. The levels of MDA, IL-6, and SOD activity were higher in the aorta of the diabetic rats compared to control rats. This study demonstrated that endothelial function was impaired in diabetes, however, supplementation with TUDCA improved the function via eNOS/Akt/PI3K, NAD(P)H, and the KATP channel. The improvement of endothelial function was associated with increased expressions of eNOS and Akt. Thus, ER stress plays a crucial role in the impairment of endothelial-dependent relaxation. Mitigating ER stress could be a potential strategy for improving endothelial dysfunction in type-2 diabetes.

Forsythoside B attenuates neuro-inflammation and neuronal apoptosis by inhibition of NF-κB and p38-MAPK signaling pathways through activating Nrf2 post spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is a ruinous neurological pathology that results in locomotor and sensory impairment. Neuro-inflammation and secondary neuronal apoptosis contribute to SCI, with anti-inflammatory therapies the focus of many SCI studies. Forsythoside B (FTS•B), a phenylethanoid glycoside extracted from the leaves of Lamiophlomis rotata Kudo, has been shown previously to have anti-inflammatory properties. Nevertheless, the therapeutic effect of FTS•B on neuro-inflammation after SCI is unknown.

METHODS

Neuro-inflammation was assessed by western blotting (WB), immunofluorescence (IF) staining, and enzyme-linked immunosorbent assay (ELISA) both in vitro and in vivo. Secondary neuronal apoptosis was simulated in a microglia-neuron co-culture model with the degree of apoptosis measured by WB, IF, and TUNEL staining. In vivo, FTS•B (10 mg/kg, 40 mg/kg) were intraperitoneally injected into SCI mice. Morphological changes following SCI were evaluated by Nissl, Hematoxylin-eosin, and Luxol Fast Blue staining. Basso Mouse Scale scores were used to evaluate locomotor function recovery.

RESULTS

FTS•B markedly decreased the levels of iNOS, COX-2 and signature mediators of inflammation. Phosphorylated p38 and nuclear factor-kappa B (NF-κB) were markedly decreased by FTS•B. Additionally, FTS•B-induced inhibition of NF-κB and p38-MAPK signaling pathways was reversed by Nrf2 downregulation. Administration of FTS•B also significantly reduced apoptosis-related protein levels indicating that FTS•B ameliorated secondary neuronal apoptosis. FTS•B administration inhibited glial scar formation, decreased neuronal death, tissue deficiency, alleviated demyelination, and promoted locomotor recovery.

CONCLUSION

FTS•B effectively attenuates neuro-inflammation and secondary neuronal apoptosis by inhibition of NF-κB and p38-MAPK signaling pathways through activating Nrf2 after SCI. This study demonstrates FTS•B to be a potential therapeutic for SCI.

TUDCA protects against tunicamycin-induced apoptosis of dorsal root ganglion neurons by suppressing activation of ER stress

The existence of endoplasmic reticulum (ER) stress in neurodegenerative diseases has been well established. Tauroursodeoxycholic acid (TUDCA) is a bile acid taurine conjugate derived from ursodeoxycholic acid, which has been reported to exert cytoprotective effects on several types of cells by inhibiting ER stress. The present study explored the effects of TUDCA on primary cultured rat dorsal root ganglion (DRG) neurons. Cell viability and apoptosis of DRG neurons treated with TUDCA and tunicamycin were detected by CellTiter-Blue assay and TUNEL staining, respectively. The protein levels and phosphorylation of apoptosis and ERS-related signaling pathway molecules were detected by western blot, and the mRNA levels of related genes were assessed by reverse transcription-quantitative PCR. Notably, TUDCA had no significant cytotoxic effect on DRG neurons at concentrations ≤250 µM. In addition, the apoptosis induced by tunicamycin exposure was markedly suppressed by TUDCA, as indicated by the percentage of TUNEL-positive cells, the activities of caspases and the changes in expression levels of critical apoptosis factors. Furthermore, the cytotoxicity of tunicamycin in DRG neurons was accompanied by an increase in malondialdehyde (MDA) content, reactive oxygen species (ROS) and lactate dehydrogenase (LDH) production, and a decrease in glutathione (GSH) levels. The changes in oxidative stress-related factors (ROS, LDH, MDA and GSH) were reversed by TUDCA. Furthermore, as determined by western blotting, the increase in C/EBP homologous protein, glucose-regulated protein 78 and cleaved caspase-12 expression following tunicamycin treatment suggested the activation of ER stress. Downregulation of ER stress components and unfolded protein response sensors by TUDCA confirmed the implication of ER stress in the effects of TUDCA on DRG neurons. In conclusion, the present study indicated that TUDCA may protect against tunicamycin-induced DRG apoptosis by suppressing the activation of ER stress. The protective effect and the therapeutic value of TUDCA in nervous system injury require further study in animal models.

Bu Shen Huo Xue decoction promotes functional recovery in spinal cord injury mice by improving the microenvironment to promote axonal regeneration

BACKGROUND

Bu-Shen-Huo-Xue (BSHX) decoction has been used in the postoperative rehabilitation of patients with spinal cord injury in China. In the present study, we aim to reveal the bioactive compounds in BSHX decoction and comprehensively explore the effects of BSHX decoction and the underlying mechanism in spinal cord injury recovery.

METHODS

The main chemical constituents in BSHX decoction were determined by UPLC-MS/MS. SCI mice were induced by a pneumatic impact device at T9-T10 level of the vertebra, and treated with BSHX decoction. Basso-Beattie-Bresnahan (BBB) score, footprint analysis, hematoxylin-eosin (H&E) staining, Nissl staining and a series of immunofluorescence staining were performed to investigate the functional recovery, glial scar formation and axon regeneration after BSHX treatment. Immunofluorescent staining of bromodeoxyuridine (BrdU), neuronal nuclei (NeuN) and glial fibrillary acidic protein (GFAP) was performed to evaluate the effect of BSHX decoction on neural stem cells (NSCs) proliferation and differentiation.

RESULTS

We found that the main compounds in BSHX decoction were Gallic acid, 3,4-Dihydroxybenzaldehyde, (+)-Catechin, Paeoniflorin, Rosmarinic acid, and Diosmetin. BSHX decoction improved the pathological findings in SCI mice through invigorating blood circulation and cleaning blood stasis in the lesion site. In addition, it reduced tissue damage and neuron loss by inhibiting astrocytes activation, and promoting the polarization of microglia towards M2 phenotype. The functional recovery test revealed that BSHX treatment improved the motor function recovery post SCI.

CONCLUSIONS

Our study provided evidence that BSHX treatment could improve the microenvironment of the injured spinal cord to promote axonal regeneration and functional recovery in SCI mice.

[Advances of the role of mitochondrial dysfunction in the spinal cord injury and its relevant treatments]

OBJECTIVE

To review the advances of the role of mitochondrial dysfunction in the spinal cord injury (SCI) and its relevant treatments.

METHODS

Focusing on various mechanisms of mitochondrial dysfunction, recent relevant literature at home and abroad was identified to summarize the therapeutic strategies for SCI.

RESULTS

Mitochondrial dysfunction is mainly manifested in abnormalities in mitochondrial energy metabolism, mitochondrial oxidative stress, mitochondrial-mediated apoptosis, mitophagy, mitochondrial permeability transition, and mitochondrial biogenesis, playing a vital role in the development of SCI. Drug that enhanced mitochondrial function have been proved beneficial for the treatment of SCI.

CONCLUSION

Mitochondrial dysfunction can serve as a potential therapeutic target for SCI, providing ideas and basis for the development of SCI therapeutic candidates in the future.

DJ-1 Alleviates Neuroinflammation and the Related Blood-Spinal Cord Barrier Destruction by Suppressing NLRP3 Inflammasome Activation via SOCS1/Rac1/ROS Pathway in a Rat Model of Traumatic Spinal Cord Injury

DJ-1 has been shown to play essential roles in neuronal protection and anti-inflammation in nervous system diseases. This study aimed to explore how DJ-1 regulates neuroinflammation after traumatic spinal cord injury (t-SCI). The rat model of spinal cord injury was established by the clamping method. The Basso, Beattie, Bresnahan (BBB) score and the inclined plane test (IPT) were used to evaluate neurological function. Western blot was then applied to test the levels of DJ-1, NLRP3, SOCS1, and related proinflammatory factors (cleaved caspase 1, IL-1β and IL-18); ROS level was also examined. The distribution of DJ-1 was assessed by immunofluorescence staining (IF). BSCB integrity was assessed by the level of MMP-9 and tight junction proteins (Claudin-5, Occludin and ZO-1). We found that DJ-1 became significantly elevated after t-SCI and was mainly located in neurons. Knockdown of DJ-1 with specific siRNA aggravated NLRP3 inflammasome-related neuroinflammation and strengthened the disruption of BSCB integrity. However, the upregulation of DJ-1 by Sodium benzoate (SB) reversed these effects and improved neurological function. Furthermore, SOCS1-siRNA attenuated the neuroprotective effects of DJ-1 and increased the ROS, Rac1 and NLRP3. In conclusion, DJ-1 may alleviate neuroinflammation and the related BSCB destruction after t-SCI by suppressing NLRP3 inflammasome activation by SOCS1/Rac1/ROS pathways. DJ-1 shows potential as a feasible target for mediating neuroinflammation after t-SCI.

Tauroursodeoxycholic Acid Reduces Neuroinflammation but Does Not Support Long Term Functional Recovery of Rats with Spinal Cord Injury

The bile acid tauroursodeoxycholic acid (TUDCA) reduces cell death under oxidative stress and inflammation. Implants of bone marrow-derived stromal cells (bmSC) are currently under investigation in clinical trials of spinal cord injury (SCI). Since cell death of injected bmSC limits the efficacy of this treatment, the cytoprotective effect of TUDCA may enhance its benefit. We therefore studied the therapeutic effect of TUDCA and its use as a combinatorial treatment with human bmSC in a rat model of SCI. A spinal cord contusion injury was induced at thoracic level T9. Treatment consisted of i.p. injections of TUDCA alone or in combination with one injection of human bmSC into the cisterna magna. The recovery of motor functions was assessed during a surveillance period of six weeks. Biochemical and histological analysis of spinal cord tissue confirmed the anti-inflammatory activity of TUDCA. Treatment improved the recovery of autonomic bladder control and had a positive effect on motor functions in the subacute phase, however, benefits were only transient, such that no significant differences between vehicle and TUDCA-treated animals were observed 1–6 weeks after the lesion. Combinatorial treatment with TUDCA and bmSC failed to have an additional effect compared to treatment with bmSC only. Our data do not support the use of TUDCA as a treatment of SCI.

Selenium nanoparticles derived from Proteus mirabilis YC801 alleviate oxidative stress and inflammatory response to promote nerve repair in rats with spinal cord injury

Microbial biotransformation and detoxification of biotoxic selenite into selenium nanoparticles (SeNPs) has emerged as an efficient technique for the utilization of selenium. SeNPs are characterized by high bioavailability and have several therapeutic effects owing to their antioxidant, anti-inflammatory and neuroprotective activities. However, their influence on microenvironment disturbances and neuroprotection after spinal cord injury (SCI) is yet to be elucidated. This study aimed to assess the influence of SeNPs on SCI and explore the underlying protective mechanisms. Overall, the proliferation and differentiation of neural stem cells were facilitated by SeNPs derived from Proteus mirabilis YC801 via the Wnt/β-catenin signaling pathway. The SeNPs increased the number of neurons to a greater extent than astrocytes after differentiation and improved nerve regeneration. A therapeutic dose of SeNPs remarkably protected the integrity of the spinal cord to improve the motor function of the hind limbs after SCI and decreased the expression of several inflammatory factors such as tumor necrosis factor-α and interleukin-6 in vivo and enhanced the production of M2-type macrophages by regulating their polarization, indicating the suppressed inflammatory response. Besides, SeNPs reversed the SCI-mediated production of reactive oxygen species. In conclusion, SeNPs treatment holds the potential to improve the disturbed microenvironment and promote nerve regeneration, representing a promising therapeutic approach for SCI.

Significant Therapeutic Effects of Adult Human Neural Stem Cells for Spinal Cord Injury Are Mediated by Monocyte Chemoattractant Protein-1 (MCP-1)

The limited capability of regeneration in the human central nervous system leads to severe and permanent disabilities following spinal cord injury (SCI) while patients suffer from no viable treatment option. Adult human neural stem cells (ahNSCs) are unique cells derived from the adult human brain, which have the essential characteristics of NSCs. The objective of this study was to characterize the therapeutic effects of ahNSCs isolated from the temporal lobes of focal cortical dysplasia type IIIa for SCI and to elucidate their treatment mechanisms. Results showed that the recovery of motor functions was significantly improved in groups transplanted with ahNSCs, where, in damaged regions of spinal cords, the numbers of both spread and regenerated nerve fibers were observed to be higher than the vehicle group. In addition, the distance between neuronal nuclei in damaged spinal cord tissue was significantly closer in treatment groups than the vehicle group. Based on an immunohistochemistry analysis, those neuroprotective effects of ahNSCs in SCI were found to be mediated by inhibiting apoptosis of spinal cord neurons. Moreover, the analysis of the conditioned medium (CM) of ahNSCs revealed that such neuroprotective effects were mediated by paracrine effects with various types of cytokines released from ahNSCs, where monocyte chemoattractant protein-1 (MCP-1, also known as CCL2) was identified as a key paracrine mediator. These results of ahNSCs could be utilized further in the preclinical and clinical development of effective and safe cell therapeutics for SCI, with no available therapeutic options at present.

Comparative Analysis of Urso- and Tauroursodeoxycholic Acid Neuroprotective Effects on Retinal Degeneration Models

Ursodeoxycholic (UDCA) and tauroursodeoxycholic (TUDCA) acids have shown neuroprotective properties in neurodegenerative diseases, but differential effects of the two bile acids have been poorly explored. The aim of this study was to evaluate the neuroprotective effects of UDCA versus TUDCA in a neuroretinal degeneration model and to compare transcriptionally regulated pathways. The WERI-Rb-1 human cone-like cell line and retinal explants were exposed to albumin and TUDCA or UDCA. Viability, cell death, and microglial activation were quantified. Transcriptionally regulated pathways were analyzed after RNA sequencing using the edgeR bioconductor package. Pre-treatment of cone-like cells with UDCA or TUDCA significantly protected cells from albumin toxicity. On retinal explants, either bile acid reduced apoptosis, necroptosis, and microglia activation at 6 h. TUDCA induced the regulation of 463 genes, whilst 31 genes were regulated by UDCA. Only nineteen common genes were regulated by both bile acids, mainly involved in iron control, cell death, oxidative stress, and cell metabolism. As compared to UDCA, TUDCA up-regulated genes involved in endoplasmic reticulum stress pathways and down-regulated genes involved in axonal and neuronal development. Either bile acid protected against albumin-induced cell loss. However, TUDCA regulated substantially more neuroprotective genes than UDCA.

Evaluation of neuroprotective and immunomodulatory properties of mesenchymal stem cells in an ex vivo retinal explant model

BACKGROUND

Glaucoma is a blinding degenerative neuropathy in which the death of retinal ganglion cells (RGCs) causes progressive loss of visual field and eventually vision. Neuroinflammation appears to be a key event in the progression and spread of this disease. Thus, microglial immunomodulation represents a promising therapeutic approach in which mesenchymal stem cells (MSCs) might play a crucial role. Their neuroprotective and regenerative potentials have already raised hope in animal models. Yet no definitive treatment has been developed, and some safety concerns have been reported in human trials. In the present study, we investigated the neuroprotective and immunomodulatory properties as well as the safety of MSCs in an ex vivo neuroretina explant model.

METHODS

Labeled rat bone marrow MSCs were placed in coculture with rat retinal explants after optic nerve axotomy. We analyzed the neuroprotective effect of MSCs on RGC survival by immunofluorescence using RBPMS, Brn3a, and NeuN markers. Gliosis and retinal microglial activation were measured by using GFAP, CD68, and ITGAM mRNA quantification and GFAP, CD68, and Iba1 immunofluorescence stainings. We also analyzed the mRNA expression of both 'M1' or classically activated state inflammatory cytokines (TNFα, IL1β, and IL6), and 'M2' or alternatively activated state microglial markers (Arginase 1, IL10, CD163, and TNFAIP6).

RESULTS

The number of RGCs was significantly higher in retinal explants cultured with MSCs compared to the control group at Day 7 following the optic nerve axotomy. Retinal explants cultured with MSCs showed a decrease in mRNA markers of gliosis and microglial activations, and immunostainings revealed that GFAP, Iba1, and CD68 were limited to the inner layers of the retina compared to controls in which microglial activation was observed throughout the retina. In addition, MSCs inhibited the M1 phenotype of the microglia. However, edema of the explants was observed in presence of MSCs, with an increase in fibronectin labeling at the surface of the explant corresponding to an epiretinal membrane-like phenotype.

CONCLUSION

Using an ex vivo neuroretina model, we demonstrated a neuroprotective and immunomodulatory effect of MSCs on RGCs. Unfortunately, the presence of MSCs also led to explant edema and epiretinal membrane formation, as described in human trials. Using the MSC secretome might offer the beneficial effects of MSCs without their potential adverse effects, through paracrine signaling.