FBXW5 reduction alleviates spinal cord injury (SCI) by blocking microglia activity: A mechanism involving p38 and JNK

Injectable Hydrogel To Deliver Bone Mesenchymal Stem Cells Preloaded with Azithromycin To Promote Spinal Cord Repair

Spinal cord injury is a disease that causes severe damage to the central nervous system. Currently, there is no cure for spinal cord injury. Azithromycin is commonly used as an antibiotic, but it can also exert anti-inflammatory effects by down-regulating M1-type macrophage genes and up-regulating M2-type macrophage genes, which may make it effective for treating spinal cord injury. Bone mesenchymal stem cells possess tissue regenerative capabilities that may help promote the repair of the injured spinal cord. In this study, our objective was to explore the potential of promoting repair in the injured spinal cord by delivering bone mesenchymal stem cells that had internalized nanoparticles preloaded with azithromycin. To achieve this objective, we formulated azithromycin into nanoparticles along with a trans-activating transcriptional activator, which should enhance nanoparticle uptake by bone mesenchymal stem cells. These stem cells were then incorporated into an injectable hydrogel. The therapeutic effects of this formulation were analyzed in vitro using a mouse microglial cell line and a human neuroblastoma cell line, as well as in vivo using a rat model of spinal cord injury. The results showed that the formulation exhibited anti-inflammatory and neuroprotective effects in vitro as well as therapeutic effects in vivo. These results highlight the potential of a hydrogel containing bone mesenchymal stem cells preloaded with azithromycin and trans-activating transcriptional activator to mitigate spinal cord injury and promote tissue repair.

Patients with Systemic Juvenile Idiopathic Arthritis (SJIA) Show Differences in Autoantibody Signatures Based on Disease Activity

Systemic juvenile idiopathic arthritis (SJIA) is a severe rheumatic disease in children. It is a subgroup of juvenile idiopathic arthritis (JIA; MIM #604302), which is the most common rheumatic disease in children. The diagnosis of SJIA often comes with a significant delay, and the classification between autoinflammatory and autoimmune disease is still discussed. In this study, we analyzed the immunological responses of patients with SJIA, using human proteome arrays presenting immobilized recombinantly expressed human proteins, to analyze the involvement of autoantibodies in SJIA. Results from group comparisons show several differentially reactive antigens involved in inflammatory processes. Intriguingly, many of the identified antigens had a high reactivity against proteins involved in the NF-κB pathway, and it is also notable that many of the detected DIRAGs are described as dysregulated in rheumatoid arthritis. Our data highlight novel proteins and pathways potentially dysregulated in SJIA and offer a unique approach to unraveling the underlying disease pathogenesis in this chronic arthropathy.

DKK3 ameliorates neuropathic pain via inhibiting ASK-1/JNK/p-38-mediated microglia polarization and neuroinflammation

BACKGROUND

Neuropathic pain is a common and severely disabling state that affects millions of people worldwide. Microglial activation in the spinal cord plays a critical role in the pathogenesis of neuropathic pain. However, the mechanisms underlying spinal microglial activation during neuropathic pain remain incompletely understood. Here, we investigated the role of Dickkopf (DKK) 3 and its interplay with microglial activation in the spinal cord in neuropathic pain.

METHODS

In this study, we investigated the effects of intrathecal injection of recombinant DKK3 (rDKK3) on mechanical allodynia and microglial activation in the spinal cord after spared nerve injury (SNI) in rats by western blot (WB), immunofluorescence (IF), quantitative polymerase chain reaction (qPCR), and enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found that SNI induced a significant decrease in the levels of DKK3, Kremen-1 and Dishevelled-1 (DVL-1) and up-regulated the expression of phosphorylated apoptosis signal-regulating kinase 1 (p-ASK1), phosphorylated c-JUN N-terminal kinase (p-JNK), phosphorylated p38 (p-p38) in the spinal cord. Moreover, our results showed that exogenous intrathecal administration of rDKK3 inhibited expression of p-ASK1, p-JNK, p-p38, promoted the transformation of microglia from M1 type to M2 type, and decreased the production of pro-inflammatory cytokines compared to the rats of SNI + Vehicle. However, these effects were reversed by intrathecal administration of Kremen-1 siRNA or Dishevelled-1 (DVL-1) siRNA.

CONCLUSIONS

These results suggest that DKK3 ameliorates neuropathic pain via inhibiting ASK-1/JNK/p-38-mediated microglia polarization and neuroinflammation, at least partly, by the Kremen-1 and DVL-1 pathways.

FBXW7alpha Promotes the Recovery of Traumatic Spinal Cord

BACKGROUND

White matter damage and neuronal cell death are incurred by spinal cord injury (SCI). FBXW7α, an important mediator of cell division and growth was investigated to explore its role in repairing the traumatic spinal cord in rats. Underlying mechanisms such as oxidative stress and inflammasomes signaling were also studied.

METHODS

Spinal cord injury in rats was established by longitudinal surgical incision from the lower to mid-thoracic vertebrae on the backside, followed by 20-g weight placed on the exposed Th12 surface for 30 min. AAV-delivered FBXW7α and -sh-FBXW7α were intrathecally injected into the rat spinal cord. Indices of oxidation, neurotrophic factors, and pyroptosis were measured by Western blot, Elisa, and RT-PCR.

RESULTS

We found the overexpression of FBXW7α in spinal cord rescue neuronal death triggered by the injury. Specifically, the nutritional condition, oxidative stress, and pyroptosis were improved. A synchronization of BNDF and GDNF expression patterns in various groups indicated the secretion of neurotrophic factors affect the outcome of SCI. The SOD1, CAT, and GSH-px were suppressed after trauma but all restored in response to FBXW7α overexpression. Inflammasomes-activated pyroptosis was incurred after the injury, and relevant biomarkers such as GSDMD, caspase-1, caspase- 11, IL-1β, and IL-18 were down-regulated after the introduction of FBXW7α into the injured cord. Additionally, up-regulating FBXW7α also repaired the mitochondria dysfunction.

CONCLUSION

Our data indicate FBXW7α probably serves as an important molecular target for the therapy of spinal cord injury.

Effects of repetitive magnetic stimulation on motor function and GAP43 and 5-HT expression in rats with spinal cord injury

Objectives

Spinal cord injury (SCI) is a disabling central nervous system disorder. This study aimed to explore the effects of repetitive trans-spinal magnetic stimulation (rTSMS) of different spinal cord segments on movement function and growth-associated protein-43 (GAP43) and 5-hydroxytryptamine (5-HT) expression in rats after acute SCI and to preliminarily discuss the optimal rTSMS treatment site to provide a theoretical foundation and experimental evidence for clinical application of rTSMS in SCI.

Methods

A rat T10 laminectomy SCI model produced by transient application of an aneurysm clip was used in the study. The rats were divided into group A (sham surgery), group B (acute SCI without stimulation), group C (T6 segment stimulation), group D (T10 segment stimulation), and group E (L2 segment stimulation).

Results

In vivo magnetic stimulation protected motor function, alleviated myelin sheath damage, decreased NgR and Nogo-A expression levels, increased GAP43 and 5-HT expression levels, and inhibited terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells and apoptosis-related protein expression in rats at 8 weeks after the surgery.

Conclusions

This study suggests that rTSMS can promote GAP43 and 5-HT expression and axonal regeneration in the spinal cord, which is beneficial to motor function recovery after acute SCI.

JNK/c-Jun-driven NLRP3 inflammasome activation in microglia contributed to retinal ganglion cells degeneration induced by indirect traumatic optic neuropathy

BACKGROUND

Indirect traumatic optic neuropathy (ITON) is a major cause of permanent loss of vision after blunt head trauma. Neuroinflammation plays a crucial role in neurodegenerative diseases. The present study concentrated on JNK/c-Jun-driven NLRP3 inflammasome activation in microglia during the degeneration of retinal ganglion cells (RGCs) in ITON.

METHODS

An impact acceleration (IA) model was employed to induce ITON, which could produce significant neurodegeneration in the visual system. Pharmacological approaches were employed to disrupt JNK and to explore whether JNK and the microglial response contribute to RGC death and axonal degeneration.

RESULTS

Our results indicated that the ITON model induced significant RGC death and axonal degeneration and activated JNK/c-Jun signaling, which could further induce the microglial response and NLRP3 inflammasome activation. Moreover, JNK disruption is sufficient to suppress NLRP3 inflammasome activation in microglia and to prevent RGC death and axonal degeneration.

CONCLUSIONS

ITON could promote JNK/c-Jun signaling, which further activates the NLRP3 inflammasome in microglia and contributes to the degeneration of axons and death of RGCs. JNK inhibition is able to suppress the inflammatory reaction and improve RGC survival. Although further work is needed to determine whether pharmacological inhibition of the NLRP3 inflammasome can prevent ITON, our findings indicated that such intervention could be promising for translational work.

Treatment with 5-methoxytryptophan attenuates microglia-induced neuroinflammation in spinal cord trauma

Neuroinflammation following spinal cord injury (SCI) leads to extensive secondary damage in neural tissue adjacent to the primary lesion foci. 5-Methoxytryptophan (5MTP) is a metabolite of tryptophan and proven to play a protective role in several inflammation-related diseases. However, the specific efficacy and molecular mechanism of 5MTP in SCI remains unknown. Here, we aimed to investigate the anti-inflammatory role of 5MTP in microglia-induced neuroinflammation and its therapeutic effect in SCI. To assess the effect of 5MTP in neuroinflammation, we used lipopolysaccharide (LPS) to stimulate microglia in vitro and detected the microglial phenotype using immunofluorescence staining, the inflammatory-related pathway using western blotting, and pro-inflammatory cytokines using ELISA and immunofluorescence. To explore the therapeutic effect of 5MTP in SCI, we performed contusion of the spinal cord in mice and measured the levels of neuroinflammation, glial accumulation, histological and functional recovery using ELISA, immunofluorescence staining, immunohistochemical staining, hematoxylin-eosin staining, Nissl staining and the Basso Mouse Scale, respectively. We found that treatment with 5MTP contributed to decreased activation of pro-inflammatory microglia and reduced the generation of inflammatory cytokines, including TNF-α, IL-1β, IL-6 and IL-18, by negative regulation of the p38-MAPK signaling pathway and NLRP3/caspase-1 expression. In vivo, administration of 5MTP showed mitigatory neuroinflammation levels associated with alleviated glial scar in SCI mice; hence, the neurological integrity and the neuronal survival, as well as locomotor function, were improved following 5MTP administration. 5MTP, as a novel anti-neuroinflammatory reagent, can attenuate activated microglia-induced secondary injury following SCI, and therefore, shows promise as a potential compound for application in a clinical trial for SCI therapy.

Butylphthalide has an Anti-Inflammatory Role in Spinal Cord Injury by Promoting Macrophage/Microglia M2 Polarization via p38 Phosphorylation

STUDY DESIGN

An experimental animal study of treatment of spinal cord injury (SCI).

OBJECTIVE

This report aims to evaluate the in vivo effects of butylphthalide NBP on SCI biology and to explore its potential mechanism.

SUMMARY OF BACKGROUND DATA

SCI causes great damage to humans. The inflammatory and reconstructive processes after SCI is regulated by activation of astroglial and microglial cells. Activated microglia/macrophages can be divided into M2 (anti-inflammatory) and M1 (pro-inflammatory) phenotypes. Butylphthalide (3-n-butylphthalide or NBP) treatment can significantly alleviate ischemic brain damage, and further study has confirmed that central neuroprotective effects can be realized by converting M1 polarized microglia/macrophages to the M2 phenotype. Thus far, it remains unknown whether NBP can modulate the transition of macrophages/microglia between the M1 and M2 phenotypes.

METHODS

We randomly divided male mice into three groups (sham group, SCI group, SCI+ NBP group). Molecular and histological tests were performed to detect the macrophage/microglia polarization as well as the potential mechanism of NBP in vivo and in vitro.

RESULT

It was found that NBP treatment significantly attenuated the motor dysfunction and neuronal apoptosis induced by SCI. Treatment with NBP could also reduce pro-inflammatory cytokine release after SCI and could facilitate macrophage/microglia M2 polarization and inhibit M1 polarization after SCI. To verify the findings in animal experiments, we examined the effect of NBP on BV2 cell polarization, the results showed that NBP treatment could enhance M2 polarization and inhibit M1 polarization, and that M2 polarization occurred in a p38-dependent manner.

CONCLUSION

NBP plays an important role in the anti-inflammatory response in SCI via the facilitation of macrophage/microglia M2 polarization as well as the inhibition of macrophage/microglia M1 polarization. The M2 polarization of macrophages/microglia occurs via activation of p38 pathway.

LEVEL OF EVIDENCE

3.

CacyBP/SIP in the rat spinal cord in norm and after transection - Influence on the phosphorylation state of ERK1/2 and p38 kinases

INTRODUCTION

CacyBP/SIP is a multifunctional protein present in various mammalian tissues, among them in brain. Recently, it has been shown that CacyBP/SIP exhibits phosphatase activity towards ERK1/2 and p38 kinases.

OBJECTIVES

The aim of our study was to analyze the localization and level of CacyBP/SIP and its substrates, phosphorylated ERK1/2 (p-ERK1/2) and phosphorylated p38 (p-p38) kinases, in an intact and transected rat spinal cord.

METHODS

To achieve our goals we have performed Western blot/densitometric analysis and double immunofluorescence staining using rat spinal cord tissue, intact and after total transection at different time points.

RESULTS

We have observed a decrease in the level of CacyBP/SIP and an increase in the level of p-ERK1/2 and of p-p38 in fragments of the spinal cord excised 1 and 3 months after transection. Moreover, immunofluorescence staining has shown that CacyBP/SIP, p-ERK1/2 or p-p38 co-localized with a neuronal marker, NeuN, and with an oligodendrocyte marker, Olig2.

CONCLUSION

The inverse correlation between CacyBP/SIP and p-ERK1/2 or p-p38 levels suggests that CacyBP/SIP may dephosphorylate p-ERK1/2 and p-p38 kinases and be involved in neural plasticity following spinal cord injury.