Zinc promotes functional recovery after spinal cord injury by activating Nrf2/HO-1 defense pathway and inhibiting inflammation of NLRP3 in nerve cells

Cynarin inhibits microglia-induced pyroptosis and neuroinflammation via Nrf2/ROS/NLRP3 axis after spinal cord injury

BACKGROUND

Spinal cord injury (SCI) elicits excess neuroinflammation and resident microglial pyroptosis, leading further terrible neurological collapse and locomotor dysfunction. However, the current clinical therapy is useless and a feasible treatment is urgent to be explored. Cynarin is a natural component in artichoke playing anti-inflammatory and anti-aging roles in hepatoprotection and cardioprotection, but it is unclear that the pharmacologic action and underlying mechanism of Cynarin in neuropathy.

METHODS

Using the SCI mouse model and the BV2 cell line, we here investigated whether Cynarin reduces neuroinflammation and pyroptosis to promote neurological recovery after SCI.

RESULTS

Our results showed that treatment with Cynarin reduces the level of neuroinflammation and microglial pyroptosis. Moreover, the mice treated with Cynarin exhibited lower level of reactive oxygen species (ROS) and cell death, less damage of neurohistology and better locomotor improvement of hindlimbs than the untreated mice and the nuclear factor erythroid 2-related factor 2 (Nrf2)-inhibited mice. Mechanically, Cynarin inhibited the assembly of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome by Nrf2-dependent expression to attenuate microglial pyroptosis and neuroinflammation.

CONCLUSIONS

To sum up, the current study suggested that administration of Cynarin is a promising compound for anti-neuroinflammation and anti-pyroptosis after SCI. It may be an efficient Nrf2 activator and a NLRP3 inhibitor for microglia in neuropathies.

Dietary zinc status is associated with ZnT3 (SLC30A3), IL-6 gene expressions and spinal cord tissue damage in spinal cord tissue in a cuprizone-induced rat Multiple Sclerosis model

The aim of this study was to investigate the effects of dietary zinc status on spinal cord tissue damage and ZnT3, IL-6 gene expressions in a cuprizone-induced rat Multiple Sclerosis (MS) model. The study was carried out on 46 adult male rats of the genus Wistar. The animals used in the study were divided into 5 groups (G) (Control 6, other groups 10). G1, Control. G2, Sham-MS: Carboxy-methyl-cellulose (KMS) solution in which Cuprizon was dissolved was given to rats by gavage daily for 8 weeks at the rate of 1 % of daily feed consumption. MS was formed by giving 1 % of the daily feed consumption cuprizon in KMS solution by gavage to the animals in G3, 4 and 5 for 8 weeks. G4 was fed with a zinc deficient (50 µg/kg zinc) diet. G5 was given intraperitoneal (ip) zinc sulfate (5 mg/kg/day) supplementation. MS formation in animals was determined by Rotarod tests and Myelin Basic Protein (MBP) gene expression analysis. ZNT3 and IL-6 gene expression levels in spinal cord tissue samples of animals by Real-Time-PCR method; MDA and GSH levels were determined by ELISA method. The highest spinal cord MDA and IL-6 levels were obtained in G3 and G4 (P<0.05). Zinc supplementation in G5 prevented the increase in the mentioned parameters and turned them into control values (P<0.05). The spinal cord GSH and ZnT3 levels of G3 and G4 were lower than all other groups (P<0.05). Zinc supplementation prevented suppression in the same parameters in G5 and reached the control values (P<0.05). The findings of the current study suggest that zinc supplementation in addition to treatment for MS may be beneficial in reducing the severity of the disease.

Zinc: a potential star for regulating peritoneal fibrosis

Peritoneal dialysis (PD) is a commonly used renal replacement therapy for patients with end-stage renal disease (ESRD). During PD, the peritoneum (PM), a semi-permeable membrane, is exposed to nonbiocompatible PD solutions. Peritonitis can occur, leading to structural and functional PM disorders, resulting in peritoneal fibrosis and ultrafiltration failure, which are important reasons for patients with ESRD to discontinue PD. Increasing evidence suggests that oxidative stress (OS) plays a key role in the pathogenesis of peritoneal fibrosis. Furthermore, zinc deficiency is often present to a certain extent in patients undergoing PD. As an essential trace element, zinc is also an antioxidant, potentially playing an anti-OS role and slowing down peritoneal fibrosis progression. This study summarises and analyses recent research conducted by domestic and foreign scholars on the possible mechanisms through which zinc prevents peritoneal fibrosis.

Malondialdehyde and Zinc May Relate to Severity of Microvascular Complications in Diabetes: A Preliminary Study on Older Adults with Type 2 Diabetes Mellitus in Northeast China

Background

Serum trace elements and oxidative stress factors are related to diabetic microvascular complications. The study was to investigate the complex relationship between trace elements, oxidative stress factors, and the severity of microvascular complications of diabetes in older adults.

Methods

The present study included patients with or without type 2 diabetes, and blood glucose, blood lipids, trace elements (iron, magnesium, zinc), oxidative stress factors (malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC)) were evaluated. Risk factors for the severity of diabetic microvascular complications in older adults with diabetes were also estimated.

Results

There were statistically significant differences in fasting blood glucose (FBG), triglycerides (TG), low density lipoprotein (LDL), glycated hemoglobin (HbAlc), MDA, NO, SOD, T-AOC, magnesium, and zinc between the two groups (P<0.05). Iron (rZinc = 0.147, rSOD = 0.180, rT-AOC = 0.193, P < 0.05) was positively correlated with zinc, SOD and T-AOC. Iron was negatively correlated with MDA (rMDA = -0.146, P < 0.05). Magnesium was positively correlated with SOD (rMagnesium = 0.147, P < 0.05). Zinc (rSOD = 0.616, rT-AOC = 0.575, P < 0.01) was positively correlated with SOD and T-AOC. Zinc (rMDA =-0.636, rNO=-0.616, P<0.01) was positively correlated with MDA and negatively correlated with NO. The course of disease (18.653, [5.726; 60.764], P <0.01), FBG (1.265, [1.059; 1.511], P <0.05), HbAlc (1.545, [1.431; 1.680], P <0.01), MDA (2.989, [1.900; 4.702], P <0.01) were risk factor for the severity of diabetic microvascular complications. Zinc (0.680, [0.503; 0.919], P < 0.05) and SOD (0.820, [0.698; 0.964], P < 0.05) were protective factors for the severity of diabetic microvascular complications.

Conclusion

Serum trace elements are related to oxidative stress levels in older adults with type 2 diabetes. The more stable trace element in older adults with diabetes, the lower the oxidative stress and the fewer microvascular complications of diabetes.

The Role of Vitamins in Spinal Cord Injury: Mechanisms and Benefits

Spinal cord injury (SCI) is a common neurological disease worldwide, often resulting in a substantial decrease in quality of life, disability, and in severe cases, even death. Unfortunately, there is currently no effective treatment for this disease. Nevertheless, current basic and clinical evidence suggests that vitamins, with their antioxidant properties and biological functions, may play a valuable role in improving the quality of life for individuals with SCI. They can promote overall health and facilitate the healing process. In this review, we discuss the mechanisms and therapeutic potential of vitamins in the treatment of SCI.

Alpha-tocopherol inhibits ferroptosis and promotes neural function recovery in rats with spinal cord injury via downregulating Alox15

Spinal cord injury (SCI) is a type of central nervous system (CNS) injury in which ferroptosis is becoming a promising target for treatment. Alpha-tocopherol (Vitamin E, Vit E) is a compound with anti-ferroptosis activity. The mechanism of alpha-tocopherol in regulating ferroptosis after SCI has not been deeply studied. In this study, rats with SCI were treated by Alpha-tocopherol based on bioinformatic analysis and molecular docking prediction. Behavioral tests and histological findings showed that Alpha-tocopherol promoted neural function recovery and tissue repairment in rats with SCI. Subsequently, regulatory effects of Alpha-tocopherol on Alox15 and ferroptosis were detected and then localized by immunofluorescence. In vitro, alpha-tocopherol improved the ROS accumulation, iron overload, lipid peroxidation and mitochondrial dysfunction. The effects of Alpha-tocopherol on the expression of Alox15, Ptgs2 and 4Hne were validated in vitro. Finally, the inhibitory effects of Alpha-tocopherol on Alox15 and ferroptosis were weakened by the mutation of 87th residue of Alox15. In summary, alpha-tocopherol could alleviate SCI-induced ferroptosis by downregulating Alox15 to promote neural function recovery in rats with SCI. Findings in this study could help further our understanding on SCI-induced ferroptosis and provide a novel insight for treating SCI.

Zinc utilization by microglia in Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia defined by two key pathological characteristics in the brain, amyloid-β (Aβ) plaques and neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau. Microglia, the primary innate immune cells of the central nervous system (CNS), provide neuroprotection through Aβ and tau clearance but may also be neurotoxic by promoting neuroinflammation to exacerbate Aβ and tau pathogenesis in AD. Recent studies have demonstrated the importance of microglial utilization of nutrients and trace metals in controlling their activation and effector functions. Trace metals, such as zinc, have essential roles in brain health and immunity, and zinc dyshomeostasis has been implicated in AD pathogenesis. As a result of these advances, the mechanisms by which zinc homeostasis influences microglial-mediated neuroinflammation in AD is a topic of continuing interest since new strategies to treat AD are needed. Here, we review the roles of zinc in AD, including zinc activation of microglia, the associated neuroinflammatory response, and the application of these findings in new therapeutic strategies.

Mechanism of Fat Mass and Obesity-Related Gene-Mediated Heme Oxygenase-1 m6A Modification in the Recovery of Neurological Function in Mice with Spinal Cord Injury

OBJECTIVES

This study examined the mechanism of fat mass and obesity-related gene (FTO)-mediated heme oxygenase-1 (HO-1) m6A modification facilitating neurological recovery in spinal cord injury (SCI) mice. FTO/HO-1 was identified as a key regulator of SCI as well as a potential target for treatment of SCI.

METHODS

An SCI mouse was treated with pcDNA3.1-FTO/pcDNA3.1-NC/Dac51. An oxygen/glucose deprivation (OGD) cell model simulated SCI, with cells treated with pcDNA3.1-FTO/si-HO-1/Dac51. Motor function and neurobehavioral evaluation were assessed using the Basso, Beattie, and Bresnahan (BBB) scale and modified neurological severity score (mNSS). Spinal cord pathology and neuronal apoptosis were assessed. Further, FTO/HO-1 mRNA and protein levels, HO-1 mRNA stability, the interaction of YTHDF2 with HO-1 mRNA, neuronal viability/apoptosis, and HO-1 m6A modification were evaluated.

RESULTS

Spinal cord injury mice exhibited reduced BBB, elevated mNSS scores, disorganized spinal cord cells, scattered nuclei, and severe nucleus pyknosis. pcDNA3.1-FTO elevated FTO mRNA, protein expression, and BBB score; reduced the mNSS score of SCI mice; decreased neuronal apoptosis; improved the cell arrangement; and improved nucleus pyknosis in spinal cord tissues. OGD decreased FTO expression. FTO upregulation ameliorated OGD-induced neuronal apoptosis. pcDNA3.1-FTO reduced HO-1 mRNA and protein and HO-1 m6A modification, while increasing HO-1 mRNA stability and FTO in OGD-treated cells. FTO upregulated HO-1 by modulating m6A modification. HO-1 downregulation attenuated the effect of FTO. pcDNA3.1-FTO/Dac51 increased the HO-1 m6A level in mouse spinal cord tissue homogenate, reduced BBB, boosted mNSS scores of SCI mice, aggravated nucleus pyknosis, and increased neuronal apoptosis in spinal cord tissues, confirming that FTO mediated HO-1 m6A modification facilitated neurological recovery in SCI mice.

CONCLUSION

The fat mass and obesity-related gene modulates HO-1 mRNA stability by regulating m6A modification levels, thereby influencing HO-1 expression and promoting neurological recovery in SCI mice.

Inhibition of UHRF1 Improves Motor Function in Mice with Spinal Cord Injury

Spinal-cord injury (SCI) is a severe condition that can lead to limb paralysis and motor dysfunction, and its pathogenesis is not fully understood. The objective of this study was to characterize the differential gene expression and molecular mechanisms in the spinal cord of mice three days after spinal cord injury. By analyzing RNA sequencing data, we identified differentially expressed genes and discovered that the immune system and various metabolic processes play crucial roles in SCI. Additionally, we identified UHRF1 as a key gene that plays a significant role in SCI and found that SCI can be improved by suppressing UHRF1. These findings provide important insights into the molecular mechanisms of SCI and identify potential therapeutic targets that could greatly contribute to the development of new treatment strategies for SCI.

Nrf2/HO-1 signaling activation alleviates cigarette smoke-induced inflammation in chronic obstructive pulmonary disease by suppressing NLRP3-mediated pyroptosis

BACKGROUND

This study examined the effect of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway on chronic obstructive pulmonary disease (COPD) and the potential molecular mechanism.

METHODS

A COPD mouse model was established by cigarette smoke exposure and administered with either ML385 or dimethyl fumarate (DMF). Airway resistance of mice was detected. IL-1β and IL-6 levels in mice alveolar lavage fluid were examined by enzyme-linked immunosorbent assay. Hematoxylin and eosin staining and immunohistochemical of lung tissues were utilized to detect lung injury and NLRP3 expression. DMF was used to treat COPD cell model constructed by exposing normal human bronchial epithelial (NHBE) cells to cigarette smoke extract. NHBE cells were transfected by NLRP3-expression vectors. Expression of proteins was detected by Western blot.

RESULTS

COPD mice showed the enhanced airway resistance, the inactivated Nrf2/HO-1 pathway and the overexpressed NLRP3, Caspase-1 and GSDMD-N proteins in lung tissues, and the increased IL-1β and IL-6 levels in alveolar lavage fluid. ML385 treatment augmented these indicators and lung injury in COPD mice. However, DMF intervention attenuated these indicators and lung injury in COPD mice. Nrf2/HO-1 pathway inactivation and overexpression of NLRP3, Caspase-1 and GSDMD-N proteins were observed in COPD cells. DMF intervention activated Nrf2/HO-1 pathway and down-regulated NLRP3, Caspase-1 and GSDMD-N proteins in COPD cells. However, NLRP3 overexpression abolished the effect of DMF on COPD cells.

CONCLUSION

Nrf2/HO-1 pathway activation may alleviate inflammation in COPD by suppressing the NLRP3-related pyroptosis. Activating the Nrf2/HO-1 pathway may be an effective method to treat COPD.

Metal profiling in coronary ischemia-reperfusion injury: Implications for KEAP1/NRF2 regulated redox signaling

Coronary ischemia-reperfusion (IR) injury results from a blockage of blood supply to the heart followed by restoration of perfusion, leading to oxidative stress induced pathological processes. Nuclear factor erythroid 2-related factor 2 (NRF2), a master antioxidant transcription factor, plays a key role in regulating redox signaling. Over the past decades, the field of metallomics has provided novel insights into the mechanism of pro-oxidant and antioxidant pathological processes. Both redox-active (e.g. Fe and Cu) and redox-inert (e.g. Zn and Mg) metals play unique roles in establishing redox balance under IR injury. Notably, Zn protects against oxidative stress in coronary IR injury by serving as a cofactor of antioxidant enzymes such as superoxide dismutase [Cu-Zn] (SOD1) and proteins such as metallothionein (MT) and KEAP1/NRF2 mediated antioxidant defenses. An increase in labile Zn2+ inhibits proteasomal degradation and ubiquitination of NRF2 by modifying KEAP1 and glycogen synthase kinase 3β (GSK3β) conformations. Fe and Cu catalyse the formation of reactive oxygen species via the Fenton reaction and also serve as cofactors of antioxidant enzymes and can activate NRF2 antioxidant signaling. We review the evidence that Zn and redox-active metals Fe and Cu affect redox signaling in coronary cells during IR and the mechanisms by which oxidative stress influences cellular metal content. In view of the unique double-edged characteristics of metals, we aim to bridge the role of metals and NRF2 regulated redox signaling to antioxidant defenses in IR injury, with a long-term aim of informing the design and application of novel therapeutics.

Traumatic Human Spinal Cord Injury: Are Single Treatments Enough to Solve the Problem?

Traumatic spinal cord injury (SCI) results in partial or complete motor deficits, such as paraplegia, tetraplegia, and sphincter control, as well as sensory disturbances and autonomic dysregulation such as arterial hypotension, lack of sweating, and alterations in skin lability. All this has a strong psychological impact on the affected person and his/her family, as well as costs to healthcare institutions with an economic burden in the short, medium, and long terms. Despite at least forty years of experimental animal studies and several clinical trials with different therapeutic strategies, effective therapy is not universally accepted. Most of the published works on acute and chronic injury use a single treatment, such as medication, trophic factor, transplant of a cell type, and so on, to block some secondary injury mechanisms or promote some mechanisms of structural/functional restoration. However, despite significant results in experimental models, the outcome is a moderate improvement in muscle strength, sensation, or eventually in sphincter control, which has been considered non-significant in human clinical trials. Here we present a brief compilation of successful individual treatments that have been applied to secondary mechanisms of action. These studies show limited neuroprotective or neurorestorative approaches in animal models and clinical trials. Thus, the few benefits achieved so far represent a rationale to further explore other strategies that seek better structural and functional restoration of the injured spinal cord.

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.

Metallothionein 3 promotes osteoclast differentiation and survival by regulating the intracellular Zn2+ concentration and NRF2 pathway

In osteoclastogenesis, the metabolism of metal ions plays an essential role in controlling reactive oxygen species (ROS) production, mitochondrial biogenesis, and survival, and differentiation. However, the mechanism regulating metal ions during osteoclast differentiation remains unclear. The metal-binding protein metallothionein (MT) detoxifies heavy metals, maintains metal ion homeostasis, especially zinc, and manages cellular redox levels. We carried out tests using murine osteoclast precursors to examine the function of MT in osteoclastogenesis and evaluated their potential as targets for future osteoporosis treatments. MT genes were significantly upregulated upon differentiation from osteoclast precursors to mature osteoclasts in response to receptor activators of nuclear factor-κB (NF-κB) ligand (RANKL) stimulation, and MT3 expression was particularly pronounced in mature osteoclasts among MT genes. The knockdown of MT3 in osteoclast precursors demonstrated a remarkable inhibition of differentiation into mature osteoclasts. In preosteoclasts, MT3 knockdown suppressed the activity of mitogen-activated protein kinase (MAPK) and NF-κB signaling pathways upon RANKL stimulation, leading to affect cell survival through elevated cleaved Caspase 3 and poly (ADP-ribose) polymerase (PARP) levels. Additionally, ROS levels were decreased, and nuclear factor erythroid 2-related factor 2 (NRF2) (a suppressor of ROS) and the downstream antioxidant proteins, such as catalase (CAT) and heme oxygenase 1 (HO-1), were more highly expressed in the MT3 preosteoclast knockdowns. mitochondrial ROS, which is involved in mitochondrial biogenesis and the production of reactive oxygen species, were similarly decreased because cAMP response element-binding (CREB) and peroxisome proliferator-activated receptor γ coactivator 1β (PGC-1β) were less activated due to MT3 depletion. Thus, by modulating ROS through the NRF2 pathway, MT3 plays a crucial role in regulating osteoclast differentiation and survival, acting as a metabolic modulator of intracellular zinc ions.

Pregnane X receptor (PXR) deficiency protects against spinal cord injury by activating NRF2/HO-1 pathway

INTRODUCTION

As a devastating neurological disease, spinal cord injury (SCI) results in severe tissue loss and neurological dysfunction. Pregnane X receptor (PXR) is a ligand-activated nuclear receptor with a major regulatory role in xenobiotic and endobiotic metabolism and recently has been implicated in the central nervous system. In the present study, we aimed to investigate the role and mechanism of PXR in SCI.

METHODS

The clip-compressive SCI model was performed in male wild-type C57BL/6 (PXR+/+ ) and PXR-knockout (PXR-/- ) mice. The N2a H2 O2 -induced injury model mimicked the pathological process of SCI in vitro. Pregnenolone 16α-carbonitrile (PCN), a mouse-specific PXR agonist, was used to activate PXR in vivo and in vitro. The siRNA was applied to knock down the PXR expression in vitro. Transcriptome sequencing analysis was performed to discover the relevant mechanism, and the NRF2 inhibitor ML385 was used to validate the involvement of PXR in influencing the NRF2/HO-1 pathway in the SCI process.

RESULTS

The expression of PXR decreased after SCI and reached a minimum on the third day. In vivo, PXR knockout significantly improved the motor function of mice after SCI, meanwhile, inhibited apoptosis, inflammation, and oxidative stress induced by SCI. On the contrary, activation of PXR by PCN negatively influenced the recovery of SCI. Mechanistically, transcriptome sequencing analysis revealed that PXR activation downregulated the mRNA level of heme oxygenase-1 (HO-1) after SCI. We further verified that PXR deficiency activated the NRF2/HO-1 pathway and PXR activation inhibited this pathway in vitro.

CONCLUSION

PXR is involved in the recovery of motor function after SCI by regulating NRF2/HO-1 pathway.

HIF-1, an important regulator in potential new therapeutic approaches to ischemic stroke

Ischemic stroke is a leading cause of disability and mortality worldwide due to the narrow therapeutic window of the only approved therapies like intravenous thrombolysis and thrombectomy. Hypoxia inducible factor-1α (HIF-1α) is a sensitive regulator of oxygen homeostasis, and its expression is rapidly induced after hypoxia/ischemia. It plays an extensive role in the pathophysiology of stroke by regulating multiple pathways including glucose metabolism, angiogenesis, neuronal survival, neuroinflammation and blood brain barrier regulation. Here, we give a brief overview of the HIF-1α-targeting strategies currently under investigation and summarise recent research on how HIF-1α is regulated in various brain cells, including neurons and microglia, at various stages in ischemic stroke. The roles of HIF-1 in stroke varies with ischemic time and degree of ischemia, are still up for debate. More focus has been placed on prospective HIF-1α targeting drugs, such as HIF-1α activator, HIF-1α stabilizers, and natural compounds. In this review, we have highlighted the regulation of HIF-1α in the novel therapeutic approaches for treatment of stroke.

Role of the NLRP3 inflammasome in gynecological disease

The NLR family pyrin domain containing 3 (NLRP3) inflammasome is involved in the innate immune system and is a three-part macromolecular complex comprising the NLRP3 protein, apoptosis-associated speck-like protein containing a CARD (ASC) and the cysteine protease pro-caspase-1. When the NLRP3 inflammasome is activated, it can produce interleukin (IL)- 1β and IL-18 and eventually lead to inflammatory cell pyroptosis. Related studies have demonstrated that the NLRP3 inflammasome can induce an immune response and is related to the occurrence and development of gynecological diseases, such as endometriosis, polycystic ovary syndrome and breast cancer. NLRP3 inflammasome inhibitors are beneficial for maintaining cellular homeostasis and tissue health and have been found effective in targeting some gynecological diseases. However, excessive inhibitor concentrations have been found to cause adverse effects. Therefore, proper control of NLRP3 inflammasome activity is critical. This paper summarizes the structure and function of the NLRP3 inflammasome and highlights the therapeutic potential of targeting it in gynecological diseases, such as endometriosis, polycystic ovary syndrome and breast cancer The application of NLRP3 inflammasome inhibitors is also discussed.

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy

INTRODUCTION

Spinal cord injury (SCI) is a central nervous system injury that is primarily traumatic and manifests as motor, sensory, and autonomic dysfunction below the level of damage. Our previous studies confirmed the ability of zinc to protect mitochondria, protect neurons and promote spinal cord recovery. However, the role of zinc in Parthanatos is unknown.

AIM

We investigated the effects of zinc in Parthanatos from oxidative stress and mitophagy. We elucidated the role of SIRT3 in providing new ideas for treating spinal cord injury.

THE RESULTS

Zinc protected SCI mice by regulating Parthanatos. On the one hand, zinc eliminated ROS directly through SIRT3 deacetylation targeting SOD2 to alleviate Parthanatos. On the other hand, zinc eliminated ROS indirectly through SIRT3-mediated promotion of mitophagy to alleviate Parthanatos.

CONCLUSION

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy.

Use of Cells, Supplements, and Peptides as Therapeutic Strategies for Modulating Inflammation after Spinal Cord Injury: An Update

Spinal cord injury is a traumatic lesion that causes a catastrophic condition in patients, resulting in neuronal deficit and loss of motor and sensory function. That loss is caused by secondary injury events following mechanical damage, which results in cell death. One of the most important events is inflammation, which activates molecules like proinflammatory cytokines (IL-1β, IFN-γ, and TNF-α) that provoke a toxic environment, inhibiting axonal growth and exacerbating CNS damage. As there is no effective treatment, one of the developed therapies is neuroprotection of the tissue to preserve healthy tissue. Among the strategies that have been developed are the use of cell therapy, the use of peptides, and molecules or supplements that have been shown to favor an anti-inflammatory environment that helps to preserve tissue and cells at the site of injury, thus favoring axonal growth and improved locomotor function. In this review, we will explain some of these strategies used in different animal models of spinal cord injury, their activity as modulators of the immune system, and the benefits they have shown.

Curcumin-Loaded Macrophage-Derived Exosomes Effectively Improve Wound Healing

This study aims to investigate the potential therapeutic effect of exosomes derived from macrophages loaded with curcumin (Exos-cur) on the healing of diabetic wounds. As a new type of biomaterial, Exos-cur has better stability, anti-inflammation, and antioxidation biological activity. In in vitro experiments, Exos-cur can promote the proliferation, migration, and angiogenesis of HUVECs (human umbilical vein endothelial cells) while reducing the ROS (reactive oxygen species) produced by HUVECs induced by high glucose, regulating the mitochondrial membrane potential, reducing cell oxidative damage, and inhibiting oxidative stress and inflammation. In the in vivo experiment, the Exos-cur treatment group had an increased percentage of wound closure and contraction compared with the diabetic wound control group. Hematoxylin-eosin staining (HE) and Masson staining showed that the Exos-cur treatment group had more advanced re-epithelialization, and the generated mature granulation tissue was rich in a large number of capillaries and newly deposited collagen fibers. Western blot and immunofluorescence analyses showed that Exos-cur can inhibit inflammation by activating the Nrf2/ARE pathway, upregulate the expression of wound healing-related molecules, promote angiogenesis, and accelerate wound healing in diabetic rats. These results show that Exos-cur has a good therapeutic effect on diabetic skin defects and provide experimental evidence for the potential clinical benefits of Exos-cur.

USP7 regulates HMOX-1 via deubiquitination to suppress ferroptosis and ameliorate spinal cord injury in rats

Heme oxygenase 1 (HMOX-1) is overexpressed in spinal cord injury (SCI) and relevant to ferroptosis. Ubiquitin-specific-processing protease 7 (USP7) has unveiled its role in regulating HMOX-1 stabilization while its function in SCI remains unknown. This study is to explore the potential molecular mechanism of the USP7-HMOX-1 axis in ferroptosis in a SCI rat model. SCI was assessed with Basso, Beattie, Bresnahan locomotion evaluation, hematoxylin-eosin histological staining, and immunofluorescence detection of NeuN. Ferroptosis was assessed by detections of the iron content, malondialdehyde and glutathione levels, mitochondrial damage, and glutathione peroxidase 4, 4-hydroxynonenal, USP7, and HMOX-1 expression in spinal cord. Co-immunoprecipitation was used to detect the binding of USP7 to HMOX-1. The ubiquitination level of HMOX-1 was measured after USP7 overexpression. USP7 expression was downregulated and HMOX-1 expression was upregulated in SCI rat models. HMOX-1 or USP7 overexpression promoted motor function recovery, ameliorated spinal cord damage, increased NeuN expression, and blocked the occurrence of ferroptosis in SCI rat models. In SCI rats, USP7 directly bound to HMOX-1 and its overexpression promoted HMOX-1 expression via deubiquitination. To sum up, USP7 overexpression facilitated the expression of HMOX-1 through deubiquitination, thereby reducing ferroptosis and alleviating SCI.

Hesperetin ameliorates spinal cord injury by inhibiting NLRP3 inflammasome activation and pyroptosis through enhancing Nrf2 signaling

Neuroinflammation is a prominent feature of traumatic spinal cord injuries (SCIs). Hesperetin exhibits anti-inflammatory effects in neurological disorders; however, the potential neuroprotective effects of hesperetin in cases of SCI remain unclear. Sprague-Dawley rats with C5 hemi-contusion injuries were used as an SCI model. Hesperetin was administered to the experimental rats in order to investigate its neuroprotective effects after SCI, and BV2 cells were pretreated with hesperetin or silencing of nuclear factor erythroid 2-related factor 2 (siNrf2), and then stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP). The therapeutic impact and molecular mechanism of hesperetin were elucidated in a series of in vivo and in vitro investigations conducted using a combination of experiments. The results of the present in vivo experiment indicated that hesperetin improved functional recovery and protected spinal cord tissue after SCI. Hesperetin attenuated oxidative stress and microglial activation, lowered malondialdehyde (MDA) levels, and elevated catalase (CAT), glutathione (GSH)-Px, and superoxide dismutase (SOD) levels. Moreover, hesperetin downregulated the expression of advanced oxygenation protein products (AOPPs), ionized calcium-binding adapter molecule 1 (Iba-1), NOD-like receptor protein 3 (NLRP3), and interleukin-1 beta (IL-1β), but increased the expression of Nrf2. In vitro studies have shown that hesperetin inhibits the generation of reactive oxygen species (ROS), as well as the neuroinflammation associated with the upregulation of Nrf2 and heme oxygenase-1 (HO-1) in BV2 cells. The results of the present study indicated that hesperetin inhibited BV2 cell pyroptosis and significantly blocked the expression of NLRP3 inflammasome proteins (NLRP3 Caspase-1 p10 apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain [ASC]) and pro-inflammatory mediators (IL-18, IL-1β). Furthermore, the silencing of Nrf2 by small interfering ribonucleic acid (siRNA) partially abolished its antioxidant effect in the aforementioned cell experiments. Collectively, these findings illustrate that through an increase in Nrf2 signaling hesperetin reduces oxidative stress and neuroinflammation by suppressing NLRP3 inflammasome activation and pyroptosis.

Zinc Promotes Spinal Cord Injury Recovery by Blocking the Activation of NLRP3 Inflammasome Through SIRT3-Mediated Autophagy

Spinal cord injuries (SCI) are complex and cause complex neurological disorders with serious implications for the health of society. Excessive neuroinflammation is one of the pathogenesis of trauma-related central nervous system (CNS) dysfunction. The initiation of inflammatory response mainly stems from neuronal necrosis in the central nervous system. The therapeutic effects and underlying mechanisms of zinc targeting neurons were investigated in vivo and in vitro using protein chips, western blotting, reactive oxygen species (ROS) activity assays, ELISA, RT-qPCR, and immunostaining. In this study, we found that zinc promotes functional recovery. Specifically, we found that zinc increased neuronal survival and suppressed lesion size and focal apoptosis levels in vivo. Zinc administration confers neuroprotection by inhibiting NLRP3 inflammasome-associated cytokine levels probed with a protein chip. Furthermore, we found that zinc promoted SIRT3-mediated induction of autophagy, which abrogated inflammatory responses and mitochondrial ROS production in the injured spinal cord and cultured neurons. These findings suggest that zinc improves neuroinflammation and improves dyskinesia after SCI. In conclusion, zinc may be a potential therapeutic immunomodulatory challenge for the treatment of trauma-related CNS dysfunction.

Therapeutic Hypothermia after Cardiac Arrest Attenuates Hindlimb Paralysis and Damage of Spinal Motor Neurons and Astrocytes through Modulating Nrf2/HO-1 Signaling Pathway in Rats

Cardiac arrest (CA) and return of spontaneous circulation (ROSC), a global ischemia and reperfusion event, lead to neuronal damage and/or death in the spinal cord as well as the brain. Hypothermic therapy is reported to protect neurons from damage and improve hindlimb paralysis after resuscitation in a rat model of CA induced by asphyxia. In this study, we investigated roles of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in the lumbar spinal cord protected by therapeutic hypothermia in a rat model of asphyxial CA. Male Sprague-Dawley rats were subjected to seven minutes of asphyxial CA (induced by injection of 2 mg/kg vecuronium bromide) and hypothermia (four hours of cooling, 33 ± 0.5 °C). Survival rate, hindlimb motor function, histopathology, western blotting, and immunohistochemistry were examined at 12, 24, and 48 h after CA/ROSC. The rats of the CA/ROSC and hypothermia-treated groups had an increased survival rate and showed an attenuated hindlimb paralysis and a mild damage/death of motor neurons located in the anterior horn of the lumbar spinal cord compared with those of the CA/ROSC and normothermia-treated groups. In the CA/ROSC and hypothermia-treated groups, expressions of cytoplasmic and nuclear Nrf2 and HO-1 were significantly higher in the anterior horn compared with those of the CA/ROSC and normothermia-treated groups, showing that cytoplasmic and nuclear Nrf2 was expressed in both motor neurons and astrocytes. Moreover, in the CA/ROSC and hypothermia-treated group, interleukin-1β (IL-1β, a pro-inflammatory cytokine) expressed in the motor neurons was significantly reduced, and astrocyte damage was apparently attenuated compared with those found in the CA/ROSC and normothermia group. Taken together, our results indicate that hypothermic therapy after CA/ROSC attenuates CA-induced hindlimb paralysis by protecting motor neurons in the lumbar spinal cord via activating the Nrf2/HO-1 signaling pathway and attenuating pro-inflammation and astrocyte damage (reactive astrogliosis).

Role of Transcription Factor Nrf2 in Pyroptosis in Spinal Cord Injury by Regulating GSDMD

Spinal cord injury (SCI) is a prevalent disease that debilitates millions of people. Nuclear factor E2-related factor 2 (Nrf2) is an important regulator of SCI. The current study sought to elaborate on the effects of Nrf2 on gasdermin D (GSDMD)-mediated microglia pyroptosis to repair SCI. The SCI rat model was established via the percussion of the T10 spinal cord and in vitro SCI model was established on BV-2 cells via lipopolysaccharide (LPS)/adenosine triphosphate (ATP) treatment. Nrf2 expression in SCI rats and BV-2 cells was overexpressed via pcDNA3.1-Nrf2 injection. Functional assays were carried out to evaluate SCI rat pathological injury, BV-2 cell viability, the release of lactate dehydrogenase (LDH), and pyroptotic factors. The binding relations of Nrf2 and microRNA (miR)-146a and miR-146a and GSDMD were verified. BV-2 pyroptosis was analyzed after the combined experiment of miR-146a-inhibitor and pcDNA3.1-GSDMD. Our experiments revealed that Nrf2 was downregulated in SCI, and Nrf2 overexpression relieved SCI pathological injury, promoted BV-2 cell viability, inhibited the release of LDH, and repressed pyroptosis. Mechanically, Nrf2 bound to the miR-146a promoter and promoted miR-146a expression, and miR-146a targeted GSDMD transcription. Rescue experiments revealed that miR-146a knockdown or GSDMD overexpression annulled the inhibitory function of Nrf2 overexpression in LPS/ATP-induced microglia pyroptosis. Overall, our findings initially highlighted that Nrf2 inhibited GSDMD-mediated microglia pyroptosis and accelerated SCI repair by repressing miR-146a.

Zinc supplementation ameliorates sorafenib-induced cognitive impairment through ROS/JNK signaling pathway

Sorafenib, a multiple kinase inhibitor, is widely used in cancer patients. Recently, clinical studies highlighted the relationship between cognitive deficits and sorafenib exposure. Zinc abundant in the body has been reported to exert neuroprotective activities. However, the effects of zinc supplementation on sorafenib-induced cognitive impairment are still unknown. In the current study, we verified that mice challenged with sorafenib displayed characteristic features of cognitive impairment. However, zinc treatment effectively improved these changes. Histopathological staining also showed that zinc significantly alleviated hippocampal microstructural and ultrastructural damages induced by sorafenib. Meanwhile, zinc significantly reduced sorafenib-induced ROS production and neuronal cells apoptosis in vivo and vitro. Additionally, we also investigated whether zinc protected against sorafenib-induced neuronal cells apoptosis via ROS/JNK pathway through treating SH-SY5Y cells with the NAC or the specific JNK activator anisomycin. The results indicated that NAC performed the same protective effects as zinc in sorafenib-challenged SH-SY5Y cells and activation of JNK by anisomycin partly abolished the protective effects of zinc. Collectively, the present study suggested that inhibition of oxidative stress and the JNK pathway might contribute to the protective effects of zinc against sorafenib-caused cognitive impairment in vivo and vitro.

Quercetin enhances survival and axonal regeneration of motoneurons after spinal root avulsion and reimplantation: experiments in a rat model of brachial plexus avulsion

BACKGROUND

Brachial plexus avulsion (BPA) physically involves the detachment of spinal nerve roots themselves and the associated spinal cord segment, leading to permanent paralysis of motor function of the upper limb. Root avulsion induces severe pathological changes, including inflammatory reaction, oxidative damage, and finally massive motoneuron apoptosis. Quercetin (QCN), a polyphenolic flavonoid found in abundance in fruit and vegetables, has been reported to possess anti-oxidative, anti-inflammatory, and neuroprotective effects in many experimental models of both central nervous system (CNS) and peripheral nervous system (PNS) disorders. The purpose of this study was to investigate whether QCN could improve motor function recovery after C5-7 ventral root avulsion and C6 reimplantation in a rat model of BPA.

METHODS

The right fifth cervical (C5) to C7 ventral roots were avulsed followed by re-implantation of only C6 to establish the spinal root avulsion plus re-implantation model in rats. After surgery, rats were treated with QCN (25, 50, and 100 mg/kg) by gavage for 2 or 8 consecutive weeks. The effects of QCN were assessed using behavior test (Terzis grooming test, TGT) and histological evaluation. The molecular mechanisms were determined by immunohistochemistry analysis and western blotting.

RESULTS

Our results demonstrated that QCN significantly expedited motor function recovery in the forelimb as shown by the increased Terzis grooming test score, and accelerated motor axon regeneration as evidenced by the ascending number of Fluoro-Ruby-labeled and P75-positive regenerative motoneurons. The raised ChAT-immunopositive and cresyl violet-stained neurons indicated the enhanced survival of motoneurons by QCN administration. Furthermore, QCN treatment markedly alleviated muscle atrophy, restored functional motor endplates in biceps and inhibited the microglial and astroglia activation via modulating Nrf2/HO-1 and neurotrophin/Akt/MAPK signaling pathway.

CONCLUSIONS

Taken together, these findings have for the first time unequivocally indicated that QCN has promising potential for further development into a novel therapeutic in conjunction with reimplantation surgery for the treatment of BPA. .

HO-1/autophagic flux axis alleviated sepsis-induced acute lung injury via inhibiting NLRP3 inflammasome

Among the multiple organ injuries induced by sepsis, acute lung injury (ALI) triggered by an excessive inflammatory response is one of the main causes contributing to patient death, and inhibition of the inflammation cascade is the key therapeutic strategy to improve prognosis. The NLRP3 inflammasome complex is considered an intracellular signaling molecule closely associated with the uncontrolled inflammatory response in sepsis-induced ALI. Therefore, exploring new targets to repress its activation is regarded as a potential therapeutic strategy. Growing evidence demonstrated that heme oxygenase-1 (HO-1) contributed to general anti-inflammation and exerted a protective role in ALI, but its underlying mechanisms have not been clarified completely. Herein, we investigated HO-1 was elevated in alveolar macrophages isolated from bronchoalveolar lavage fluid (BALF) of sepsis mice. HO-1 abundance suppressed NLRP3 inflammasome complex activation and attenuated pro-inflammatory cytokines release, thereby alleviating sepsis-induced ALI. Whereas inhibition of HO-1 reached the opposite effect. Meanwhile, HO-1 is an effective and functionally relevant regulator of autophagic flux. HO-1 activator decreased the expression of P62 and enhanced the LC3 II/LC3 I ratio, resulting in autophagic flux activation. In addition, the protective effects HO-1 exerted in sepsis-induced ALI could be abolished by autophagic flux inhibitor. Autophagic flux activator could suppress NLRP3 inflammasome activation and attenuate ALI, while autophagic flux inhibitor had the opposite effect. In conclusion, our study revealed increased HO-1 expression inhibited the level of NLRP3 inflammasome via regulating the activation of autophagic flux, thus attenuating inflammatory response and alleviating sepsis-induced ALI.

Pyroptosis in spinal cord injury

Spinal cord injury (SCI) often brings devastating consequences to patients and their families. Pathophysiologically, the primary insult causes irreversible damage to neurons and glial cells and initiates the secondary damage cascade, further leading to inflammation, ischemia, and cells death. In SCI, the release of various inflammatory mediators aggravates nerve injury. Pyroptosis is a new pro-inflammatory pattern of regulated cell death (RCD), mainly mediated by caspase-1 or caspase-11/4/5. Gasdermins family are pore-forming proteins known as the executor of pyroptosis and the gasdermin D (GSDMD) is best characterized. Pyroptosis occurs in multiple central nervous system (CNS) cell types, especially plays a vital role in the development of SCI. We review here the evidence for pyroptosis in SCI, and focus on the pyroptosis of different cells and the crosstalk between them. In addition, we discuss the interaction between pyroptosis and other forms of RCD in SCI. We also summarize the therapeutic strategies for pyroptosis inhibition, so as to provide novel ideas for improving outcomes following SCI.

Trehalose-Carnosine Prevents the Effects of Spinal Cord Injury Through Regulating Acute Inflammation and Zinc(II) Ion Homeostasis

Spinal cord injury (SCI) leads to long-term and permanent motor dysfunctions, and nervous system abnormalities. Injury to the spinal cord triggers a signaling cascade that results in activation of the inflammatory cascade, apoptosis, and Zn(II) ion homeostasis. Trehalose (Tre), a nonreducing disaccharide, and L-carnosine (Car), (β-alanyl-L-histidine), one of the endogenous histidine dipeptides have been recognized to suppress early inflammatory effects, oxidative stress and to possess neuroprotective effects. We report on the effects of the conjugation of Tre with Car (Tre-car) in reducing inflammation in in vitro and in vivo models. The in vitro study was performed using rat pheochromocytoma cells (PC12 cell line). After 24 h, Tre-car, Car, Tre, and Tre + Car mixture treatments, cells were collected and used to investigate Zn²⁺ homeostasis. The in vivo model of SCI was induced by extradural compression of the spinal cord at the T6-T8 levels. After treatments with Tre, Car and Tre-Car conjugate 1 and 6 h after SCI, spinal cord tissue was collected for analysis. In vitro results demonstrated the ionophore effect and chelating features of L-carnosine and its conjugate. In vivo, the Tre-car conjugate treatment counteracted the activation of the early inflammatory cascade, oxidative stress and apoptosis after SCI. The Tre-car conjugate stimulated neurotrophic factors release, and influenced Zn²⁺ homeostasis. We demonstrated that Tre-car, Tre and Car treatments improved tissue recovery after SCI. Tre-car decreased proinflammatory, oxidative stress mediators release, upregulated neurotrophic factors and restored Zn²⁺ homeostasis, suggesting that Tre-car may represent a promising therapeutic agent for counteracting the consequences of SCI.

Melatonin Attenuates Spinal Cord Injury in Mice by Activating the Nrf2/ARE Signaling Pathway to Inhibit the NLRP3 Inflammasome

Background: Spinal cord injury (SCI) is a central nervous system (CNS) trauma involving inflammation and oxidative stress, which play important roles in this trauma’s pathogenesis. Therefore, controlling inflammation is an effective strategy for SCI treatment. As a hormone, melatonin is capable of producing antioxidation and anti-inflammation effects. In the meantime, it also causes a neuroprotective effect in various neurological diseases. Nrf2/ARE/NLRP3 is a well-known pathway in anti-inflammation and antioxidation, and Nrf2 can be positively regulated by melatonin. However, how melatonin regulates inflammation during SCI is poorly explored. Therefore, it was investigated in this study whether melatonin can inhibit the NLRP3 inflammasome through the Nrf2/ARE signaling pathway in a mouse SCI model. Methods: A model of SCI was established in C57BL/6 mice and PC12 cells. The motor function of mice was detected by performing an open field test, and Nissl staining and terminal deoxynucleotidyl transferase dUTP nick end labeling were carried out to evaluate the survival of neurons. Mitochondrial dysfunction was detected by transmission electron microscopy (TEM) and by assessing the mitochondrial membrane potential. In addition, the expression of NLRP3 inflammasome and oxidative-stress-related proteins were detected through Western blot and immunofluorescence double staining. Results: By inhibiting neuroinflammation and reducing neuronal death, melatonin promotes the recovery of neuromotor function. Besides this, melatonin is able to reduce the damage that causes neuronal mitochondrial dysfunction, reduce the level of reactive oxygen species (ROS) and malondialdehyde, and enhance the activity of superoxide dismutase and the production of glutathione peroxidase. Mechanically, melatonin inhibits the activation of NLRP3 inflammasomes and reduces the secretion of pro-inflammatory factors through the Nrf2/ARE signaling. Conclusions: In conclusion, melatonin inhibits the NLRP3 inflammasome through stimulation of the Nrf2/ARE pathway, thereby suppressing neuroinflammation, reducing mitochondrial dysfunction, and improving the recovery of nerve function after SCI.

Polyphenols Targeting Oxidative Stress in Spinal Cord Injury: Current Status and Future Vision

A spinal cord injury (SCI) occurs when the spinal cord is deteriorated or traumatized, leading to motor and sensory functions lost even totally or partially. An imbalance within the generation of reactive oxygen species and antioxidant defense levels results in oxidative stress (OS) and neuroinflammation. After SCI, OS and occurring pathways of inflammations are significant strenuous drivers of cross-linked dysregulated pathways. It emphasizes the significance of multitarget therapy in combating SCI consequences. Polyphenols, which are secondary metabolites originating from plants, have the promise to be used as alternative therapeutic agents to treat SCI. Secondary metabolites have activity on neuroinflammatory, neuronal OS, and extrinsic axonal dysregulated pathways during the early stages of SCI. Experimental and clinical investigations have noted the possible importance of phenolic compounds as important phytochemicals in moderating upstream dysregulated OS/inflammatory signaling mediators and axonal regeneration's extrinsic pathways after the SCI probable significance of phenolic compounds as important phytochemicals in mediating upstream dysregulated OS/inflammatory signaling mediators. Furthermore, combining polyphenols could be a way to lessen the effects of SCI.

Main Cations and Cellular Biology of Traumatic Spinal Cord Injury

Traumatic spinal cord injury is a life-changing condition with a significant socio-economic impact on patients, their relatives, their caregivers, and even the community. Despite considerable medical advances, there is still a lack of options for the effective treatment of these patients. The major complexity and significant disabling potential of the pathophysiology that spinal cord trauma triggers are the main factors that have led to incremental scientific research on this topic, including trying to describe the molecular and cellular mechanisms that regulate spinal cord repair and regeneration. Scientists have identified various practical approaches to promote cell growth and survival, remyelination, and neuroplasticity in this part of the central nervous system. This review focuses on specific detailed aspects of the involvement of cations in the cell biology of such pathology and on the possibility of repairing damaged spinal cord tissue. In this context, the cellular biology of sodium, potassium, lithium, calcium, and magnesium is essential for understanding the related pathophysiology and also the possibilities to counteract the harmful effects of traumatic events. Lithium, sodium, potassium-monovalent cations-and calcium and magnesium-bivalent cations-can influence many protein-protein interactions, gene transcription, ion channel functions, cellular energy processes-phosphorylation, oxidation-inflammation, etc. For data systematization and synthesis, we used the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) methodology, trying to make, as far as possible, some order in seeing the "big forest" instead of "trees". Although we would have expected a large number of articles to address the topic, we were still surprised to find only 51 unique articles after removing duplicates from the 207 articles initially identified. Our article integrates data on many biochemical processes influenced by cations at the molecular level to understand the real possibilities of therapeutic intervention-which must maintain a very narrow balance in cell ion concentrations. Multimolecular, multi-cellular: neuronal cells, glial cells, non-neuronal cells, but also multi-ionic interactions play an important role in the balance between neuro-degenerative pathophysiological processes and the development of effective neuroprotective strategies. This article emphasizes the need for studying cation dynamics as an important future direction.

Zinc improves neurological recovery by promoting angiogenesis via the astrocyte-mediated HIF-1α/VEGF signaling pathway in experimental stroke

BACKGROUND

Ischemic stroke is a serious cerebrovascular disease with high morbidity and disability. Zinc accumulation has been shown to play a vital role in neuronal death and blood-brain barrier damage following ischemia in acute stage. However, almost nothing is known about whether zinc is involved in neurological recovery in ischemic prolonged period. This study investigates whether zinc promotes neurological recovery through astrocytes-induced angiogenesis during ischemic repair phase.

METHODS

Sprague-Dawley rats were subjected to 2 h ischemia/14, 21, and 28 days reperfusion by middle cerebral artery occlusion, then administered ZnCl₂ (10 mg/kg) via intraperitoneally daily from 7 days to tissue collection to observe brain tissue morphology, neurological function recovery by cortical width index, Adhesive removal test, and Forelimb placing test. Angiogenesis, astrocyte activation, and HIF-1α/VEGF pathway were assessed via Western blot, immunofluorescence, and BrdU method in vivo and in vitro.

RESULTS

The results showed that zinc significantly alleviated brain atrophy and improved neurological function recovery during the cerebral ischemia repair stage. Zinc significantly increased the protein levels of HIF-1α, VEGF-A, and VEGF-R2 in astrocytes, and promoted angiogenesis during cerebral ischemia repair. In vitro and in vivo studies confirmed that zinc promoted angiogenesis via the astrocyte-mediated HIF-1α/VEGF signaling pathway.

CONCLUSIONS

Zinc significantly improves neurological function recovery during the cerebral ischemia repair stage, providing new evidence supporting zinc as a potential therapeutic target for ischemic stroke by promoting astrocyte induced angiogenesis.

Nrf2 signaling in the oxidative stress response after spinal cord injury

Spinal cord injury (SCI) is a central nervous system trauma that can cause severe neurological impairment. A series of pathological and physiological changes after SCI (e.g., inflammation, oxidative stress, apoptosis, and mitochondrial dysfunction) promotes further deterioration of the microenvironment at the site of injury, leading to aggravation of neurological function. The multifunctional transcription factor NF-E2 related factor 2 (Nrf2) has long been considered a key factor in antioxidant stress. Therefore, Nrf2 may be an ideal therapeutic target for SCI. A comprehensive understanding of the function and regulatory mechanism of Nrf2 in the pathophysiology of SCI will aid in the development of targeted therapeutic strategies for SCI. This review discusses the roles of Nrf2 in SCI, with the aim of aiding in further elucidation of SCI pathophysiology and in efforts to provide Nrf2-targeted strategies for the treatment of SCI.

Recent Advances in the Role of Nuclear Factor Erythroid-2-Related Factor 2 in Spinal Cord Injury: Regulatory Mechanisms and Therapeutic Options

Nuclear factor erythroid-2-related factor 2 (Nrf2) is a pleiotropic transcription factor, and it has been documented that it can induce defense mechanisms both oxidative stress and inflammatory injury. At present, more and more evidences show that the Nrf2 signaling pathway is a key pharmacological target for the treatment of spinal cord injury (SCI), and activating the Nrf2 signaling pathway can effectively treat the inflammatory injury and oxidative stress after SCI. This article firstly introduces the biological studies of the Nrf2 pathway. Meanwhile, it is more powerful to explain that activating the Nrf2 signaling pathway can effectively treat SCI by deeply exploring the relationship between Nrf2 and oxidative stress, inflammatory injury, and SCI. In addition, several potential drugs for the treatment of SCI by promoting Nrf2 activation and Nrf2-dependent gene expression are reviewed. And some other treatment strategies of SCI by modulating the Nrf2 pathway are also summarized. It will provide new ideas and directions for the treatment of SCI.

Astrocytic Nrf2 expression protects spinal cord from oxidative stress following spinal cord injury in a male mouse model

BACKGROUND

Spinal cord injury (SCI) induces a multitude of deleterious processes, including neuroinflammation and oxidative stress (OS) which contributed to neuronal damage and demyelination. Recent studies have suggested that increased formation of reactive oxygen species (ROS) and the consequent OS are critical events associated with SCI. However, there is still little information regarding the impact of these events on SCI. Astrocytes are key regulators of oxidative homeostasis in the CNS and astrocytic antioxidant responses promote the clearance of oxidants produced by neurons. Therefore, dysregulation of astrocyte physiology might largely contribute to oxidative damage. Nuclear factor erythroid 2-related factor 2 (Nrf2) is the main transcriptional regulator of cellular anti-oxidative stress responses.

METHODS

In the current study, we hypothesized that astrocytic activation of Nrf2 protects the spinal cord post injury via suppression of neuroinflammation. Thus, using mice line with a GFAP-specific kelch-like ECH-associated protein 1 (Keap1)-deletion, we induced a hyperactivation of Nrf2 in astrocytes and further its effects on SCI outcomes. SCI-induction was performed in mice using the Infinite Horizon Spinal Cord Impactor with a force of 60 kdyn. To assess the quantitative pattern of Nrf2/ARE-activation, we included transgenic ARE-Luc mice. Data were analyzed with GraphPad Prism 8 (GraphPad Software Inc., San Diego, CA, USA). Brown-Forsythe test was performed to test for equal variances and normal distribution was tested with Shapiro-Wilk.

RESULTS

In ARE-Luc mice, a significant induction of luciferase-activity was observed as early as 1 day post-injury, indicating a functional role of Nrf2-activity at the epicenter of SCI. Furthermore, SCI induced loss of neurons and oligodendrocytes, demyelination and inflammation in wild type mice. The loss of myelin and oligodendrocytes was clearly reduced in Keap1 KO mice. In addition, Keap-1 KO mice showed a significantly better locomotor function and lower neuroinflammation responses compared to wild type mice.

CONCLUSIONS

In summary, our in vivo bioluminescence data showed Nrf2-ARE activation during primary phase of SCI. Furthermore, we found that cell specific hyperactivation of Nrf2 was sufficient to protect the spinal cord against injury which indicate a promising therapeutic approach for SCI-treatment.

Quercetin Can Improve Spinal Cord Injury by Regulating the mTOR Signaling Pathway

The pathogenesis of spinal cord injury (SCI) is complex. At present, there is no effective treatment for SCI, with most current interventions focused on improving the symptoms. Inflammation, apoptosis, autophagy, and oxidative stress caused by secondary SCI may instigate serious consequences in the event of SCI. The mammalian target of rapamycin (mTOR), as a key signaling molecule, participates in the regulation of inflammation, apoptosis, and autophagy in several processes associated with SCI. Quercetin can reduce the loss of myelin sheath, enhance the ability of antioxidant stress, and promote axonal regeneration. Moreover, quercetin is also a significant player in regulating the mTOR signaling pathway that improves pathological alterations following neuronal injury. Herein, we review the therapeutic effects of quercetin in SCI through its modulation of the mTOR signaling pathway and elaborate on how it can be a potential interventional agent for SCI.

Reverse Adverse Immune Microenvironments by Biomaterials Enhance the Repair of Spinal Cord Injury

Spinal cord injury (SCI) is a severe and traumatic disorder that ultimately results in the loss of motor, sensory, and autonomic nervous function. After SCI, local immune inflammatory response persists and does not weaken or disappear. The interference of local adverse immune factors after SCI brings great challenges to the repair of SCI. Among them, microglia, macrophages, neutrophils, lymphocytes, astrocytes, and the release of various cytokines, as well as the destruction of the extracellular matrix are mainly involved in the imbalance of the immune microenvironment. Studies have shown that immune remodeling after SCI significantly affects the survival and differentiation of stem cells after transplantation and the prognosis of SCI. Recently, immunological reconstruction strategies based on biomaterials have been widely explored and achieved good results. In this review, we discuss the important factors leading to immune dysfunction after SCI, such as immune cells, cytokines, and the destruction of the extracellular matrix. Additionally, the immunomodulatory strategies based on biomaterials are summarized, and the clinical application prospects of these immune reconstructs are evaluated.

Regulation of NLRP3 inflammasome by zinc supplementation in Behçet's disease patients: A double-blind, randomized placebo-controlled clinical trial

BACKGROUND

Overproduction of NLRP3 inflammasome complex is one of the causes of Behcet's disease's (BD) auto-inflammatory nature. The aim of current study was to examine the effect of zinc supplementation on NLRP3 inflammasome expression; as well as clinical manifestations of BD.

METHODS

In this double-blind parallel placebo-controlled randomized clinical trial, 50 BD patients were randomly allocated into either zinc gluconate (30 mg/day elemental zinc) or placebo groups for 12 weeks. The mRNA expression of NLRP3 and caspase-1 in the leukocytes, serum level of zinc and IL-1β, anthropometric measures, and clinical manifestations of patients were collected at pre- and post-intervention phase. The Iranian Behçet's disease dynamic activity measure (IBDDAM) was scored to measure the treatment effect using the calculation of number needed to treat (NNT). Analysis of covariance was performed to obtain the corresponding effect sizes.

RESULTS

Zinc gluconate led to a significant improvement in genital ulcer (P = 0.019). Zinc supplementation decreased NLRP3 and caspase-1 genes expression compared with placebo group (baseline-adjusted P-value = 0.046 for NLRP3 and P-value = 0.003 for caspase-1), even after adjustment for the effect of confounding factors (baseline- and confounders-adjusted P-value = 0.032 for NLRP3 and P-value = 0.004 for caspase-1). Baseline and confounders adjusted effect size demonstrated that zinc was effective in reducing the serum level of IL-1β (P = 0.046). The NNT [95 %CI] for the rate of IBDDAM improvement was 3 [1.7-8.5].

CONCLUSIONS

Zinc gluconate supplementation (30 mg/day) for a 3-month period can be considered as an adjuvant therapy in alleviating inflammation and genital ulcer among BD patients.

Effects of faba bean (Vicia faba L.) on fillet quality of Yellow River carp (Cyprinus carpio) via the oxidative stress response

In order to further explain the fillet texture improvement of Yellow River carp (Cyprinus carpio) fed with faba bean (Vicia faba L.), a three-month rearing trial was conducted to investigate fatty acid composition, antioxidant capacity, myofiber development, collagen deposition and transcriptome in white muscle of two farmed carp groups (One was fed only faba bean, the other was fed commercial diet). As a strong oxidant, faba bean changed fatty acids composition in white muscle, especially DHA and EPA, up-regulated the levels of reactive oxygen species (ROS) and down-regulated major antioxidant enzyme activities in the hepatopancreas and white muscle. Through the analysis of transcriptome and subsequent verification analysis, we speculated that the increase of ROS led to the decrease of myofiber diameter and collagen metabolism. This study provides a theoretical basis for further understanding the regulation of faba bean on fillet texture characteristic of Yellow River carp.

Homeodomain Interacting Protein Kinase 2-Modified Rat Spinal Astrocytes Affect Neurofunctional Recovery After Spinal Cord Injury

BACKGROUND

Spinal cord injury (SCI) is regarded as an acute neurological disorder, and astrocytes play a role in the progression of SCI.

OBJECTIVE

Herein, we investigated the roles of homeodomain-interacting protein kinase 2 (HIPK2)- modified rat spinal astrocytes in neurofunctional recovery after SCI.

METHODS

Rat spinal astrocytes were cultured, isolated, and then identified through microscopic observation and immunofluorescence staining. Astrocytes were infected with the adenovirus vector overexpressing HIPK2 for modification, and proliferation and apoptosis of astrocytes were examined using Cell Counting Kit-8 method and flow cytometry. SCI rat models were established and treated with astrocytes or HIPK2-modified astrocytes. Subsequently, rat motor ability was analyzed via the Basso-Beattie-Bresnahan (BBB) scoring and inclined-plane test, and the damage to spinal cord tissues and neuronal survival were observed via Hematoxylin-eosin staining and Nissl staining. The levels of HIPK2, brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and nuclear factor erythroid 2- related transcription factor 2 (Nrf2)/antioxidant response element (ARE) pathway-related proteins were detected.

RESULTS

Rat spinal astrocytes were harvested successfully. HIPK2 overexpression accelerated the proliferation and repressed the apoptosis of rat spinal astrocytes. Rat spinal astrocytes treatment increased BBB points and the maximum angle at which SCI rats remained stable, ameliorated damage to spinal cord tissues, increased the number of neurons, and attenuated neural damage and inflammation, while the treatment of HIPK2-modified rat spinal astrocytes imparted more pronounced effects to the neurofunctional recovery of SCI rats. Meanwhile, HIPK2-modified rat spinal astrocytes further activated the Nrf2/ARE pathway.

CONCLUSION

HIPK2-modified rat spinal astrocytes facilitated neurofunctional recovery and activated the Nrf2/ARE pathway after SCI.

Supplementation With Vitamin E, Zinc, Selenium, and Copper Re-Establishes T-Cell Function and Improves Motor Recovery in a Rat Model of Spinal Cord Injury

Spinal cord injury (SCI) causes a dysfunction of sympathetic nervous system innervation that affects the immune system, leading to immunosuppression syndrome (ISS) and contributing to patient degeneration and increased risk of several infections. A possible therapeutic strategy that could avoid further patient deterioration is the supplementation with Vitamin E or trace elements, such as Zinc, Selenium, and Copper, which individually promotes T-cell differentiation and proliferative responses. For this reason, the aim of the present study was to evaluate whether Vitamin E, Zinc, Selenium, and Copper supplementation preserves the number of T-lymphocytes and improves their proliferative function after traumatic SCI. Sprague–Dawley female rats were subjected to moderate SCI and then randomly allocated into three groups: (1) SCI + supplements; (2) SCI + vehicle (olive oil and phosphate-buffered saline); and (3) sham-operated rats. In all rats, the intervention was initiated 15 min after SCI and then administered daily until the end of study. Locomotor recovery was assessed at 7 and 15 days after SCI. At 15 days after supplementation, the quantification of the number of T-cells and its proliferation function were examined. Our results showed that the SCI + supplements group presented a significant improvement in motor recovery at 7 and 15 days after SCI. In addition, this group showed a better T-cell number and proliferation rate than that observed in the group with SCI + vehicle. Our findings suggest that Vitamin E, Zinc, Selenium, and Copper supplementation could be part of a therapy for patients suffering from acute SCI, helping to preserve T-cell function, avoiding complications, and promoting a better motor recovery. All procedures were approved by the Animal Bioethics and Welfare Committee (Approval No. 201870; CSNBTBIBAJ 090812960).

Zinc Promotes Microglial Autophagy Through NLRP3 Inflammasome Inactivation via XIST/miR-374a-5p Axis in Spinal Cord Injury

Zinc has reported to play a neuroprotective role in the development of spinal cord injury (SCI). The protective mechanism of zinc remains to be uncovered. The aim of the current study was to investigate the neuroprotective mechanism of zinc in the progression of SCI. The C57BL/6J mouse SCI model was established to confirm the protective role of zinc in vivo, while the cellular model was induced in mouse microglial BV2 cells by using lipopolysaccharide (LPS). The expression levels of XIST, miR-374a-5p and NLRP3 inflammasome as well as the autophagy-related proteins were detected using real-time PCR and immunoblotting. Cell viability was assessed by CCK-8 assay. Apoptosis was evaluated by TUNEL staining, flow cytometry, the determination of apoptosis-related proteins. The target relationship was confirmed by luciferase reporter assays. Zinc improved locomotor function in SCI mice and alleviated LPS-induced BV2 cell injuries by inhibiting apoptosis and initiating autophagy processes. XIST and NLRP3 inflammasome was upregulated while miR-374a-5p was downregulated in spinal cords of SCI mice and LPS-treated BV2 cells. All these effects were inhibited by Zinc treatment. XIST knockdown triggered microglial autophagy-mediated NLRP3 inactivation in LPS-induced BV2 cells by regulating miR-374a-5p. Zinc treatment protected BV2 cells from LPS-induced cell injury by the downregulation of XIST. This process might be through autophagy‑mediated NLRP3 inflammasome inactivation by targeting miR-374a-5p. Zinc downregulates XIST and induces neuroprotective effects against SCI by promoting microglial autophagy-induced NLRP3 inflammasome inactivation through regulating miR-374a-5p. Our finding provides novel opportunities for the understanding of zinc-related therapy of SCI.

Zinc Regulates Glucose Metabolism of the Spinal Cord and Neurons and Promotes Functional Recovery after Spinal Cord Injury through the AMPK Signaling Pathway

Spinal cord injury (SCI) is a traumatic disease that can cause severe nervous system dysfunction. SCI often causes spinal cord mitochondrial dysfunction and produces glucose metabolism disorders, which affect neuronal survival. Zinc is an essential trace element in the human body and plays multiple roles in the nervous system. This experiment is intended to evaluate whether zinc can regulate the spinal cord and neuronal glucose metabolism and promote motor functional recovery after SCI. Then we explore its molecular mechanism. We evaluated the function of zinc from the aspects of glucose uptake and the protection of the mitochondria in vivo and in vitro. The results showed that zinc elevated the expression level of GLUT4 and promoted glucose uptake. Zinc enhanced the expression of proteins such as PGC-1α and NRF2, reduced oxidative stress, and promoted mitochondrial production. In addition, zinc decreased neuronal apoptosis and promoted the recovery of motor function in SCI mice. After administration of AMPK inhibitor, the therapeutic effect of zinc was reversed. Therefore, we concluded that zinc regulated the glucose metabolism of the spinal cord and neurons and promoted functional recovery after SCI through the AMPK pathway, which is expected to become a potential treatment strategy for SCI.

Nerve growth factor loaded macrophage-derived nanovesicles for inhibiting neuronal apoptosis after spinal cord injury

Spinal cord injury (SCI) is an extremely destructive central nervous system lesion. Studies have shown that NGF can promote nerve regeneration after SCI. However, it cannot produce the desired effect due to its stability in the body and is difficulty in passing through the blood-brain barrier. In this study, we prepared nanovesicles derived from macrophage membrane encapsulating NGF (NGF-NVs) as a drug carrier for the treatment of SCI. Cell experiments showed that NGF-NVs were effectively taken up by PC12 cells and inhibited neuronal apoptosis. In vivo imaging experiments, a large quantity of NGF was delivered to the injured site with the aid of the good targeting of NVs. In animal experiments, NGF-NVs improved the survival of neurons by significantly activating the PI3K/AKT signaling pathway and had good behavioral and histological recovery effects after SCI. Therefore, NVs are a potential drug delivery vector for SCI therapy.

Protective Effects of Zinc on Spinal Cord Injury

Spinal cord injury is a serious disease of the central nervous system, but there is no effective treatment. And zinc is an essential nutrient for human body and participates in many physiological processes, such as immune response, homeostasis, oxidative stress, cell cycle progression, DNA replication, DNA damage repair, apoptosis, and aging. This article mainly summarizes that zinc could predict the prognosis and treat the spinal cord injury. Especially, zinc could help to inhibit inflammation, regulate autophagy, and reduce oxidative stress. However, excessive zinc will damage neurons.

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

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

Zinc attenuates ferroptosis and promotes functional recovery in contusion spinal cord injury by activating Nrf2/GPX4 defense pathway

AIM

Spinal cord injury (SCI) involves multiple pathological processes. Ferroptosis has been shown to play a critical role in the injury process. We wanted to explore whether zinc can inhibit ferroptosis, reduce inflammation, and then exert a neuroprotective effect.

METHODS

The Alice method was used to establish a spinal cord injury model. The Basso Mouse Scale (BMS), Nissl staining, hematoxylin-eosin staining, and immunofluorescence analysis were used to investigate the protective effect of zinc on neurons on spinal cord neurons and the recovery of motor function. The regulation of the nuclear factor E2/heme oxygenase-1 (NRF2/HO-1) pathway was assessed, the levels of essential ferroptosis proteins were measured, and the changes in mitochondria were confirmed by transmission electron microscopy and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine iodide (JC-1) staining. In vitro experiments using VSC4.1 (spinal cord anterior horn motor neuroma cell line), 4-hydroxynonenal (4HNE), reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), lipid peroxides, and finally the levels of inflammatory factors were detected to assess the effect of zinc.

RESULTS

Zinc reversed behavioral and structural changes after SCI. Zinc increased the expression of NRF2/HO-1, thereby increasing the content of glutathione peroxidase 4 (GPX4), SOD, and GHS and reducing the levels of lipid peroxides, MDA, and ROS. Zinc also rescued injured mitochondria and effectively reduced spinal cord injury and the levels of inflammatory factors, and the NRF2 inhibitor Brusatol reversed the effects of zinc.

CONCLUSION

Zinc promoted the degradation of oxidative stress products and lipid peroxides through the NRF2/HO-1 and GPX4 signaling pathways to inhibit ferroptosis in neurons.