Progranulin deficiency exacerbates spinal cord injury by promoting neuroinflammation and cell apoptosis in mice

Selenomethionine Inhibited HADV-Induced Apoptosis Mediated by ROS through the JAK-STAT3 Signaling Pathway

Adenovirus (HAdV) can cause severe respiratory infections in children and immunocompromised patients. There is a lack of specific therapeutic drugs for HAdV infection, and the study of anti-adenoviral drugs has far-reaching clinical implications. Elemental selenium can play a specific role as an antioxidant in the human immune cycle by non-specifically binding to the amino acid methionine in body proteins. Methods: The antiviral mechanism of selenomethionine was explored by measuring cell membrane status, intracellular DNA status, cytokine secretion, mitochondrial membrane potential, and ROS production. Conclusions: Selenomethionine improved the regulation of ROS-mediated apoptosis by modulating the expression of Jak1/2, STAT3, and BCL-XL, which led to the inhibition of apoptosis. It is anticipated that selenomethionine will offer a new anti-adenoviral therapeutic alternative.

20-Deoxyingenol Activates Mitophagy Through TFEB and Promotes Functional Recovery After Spinal Cord Injury

Spinal cord injury (SCI) can lead to permanent paralysis and various motor, sensory and autonomic nervous system dysfunction. The complex pathophysiological processes limit the effectiveness of many clinical treatments. Mitochondria has been reported to play a key role in the pathogenesis of SCI; while mitophagy is a protective mechanism against mitochondrial dysfunction. However, there is recently little drugs that may targeted activate mitophagy to treat SCI. In this study, we evaluated the role of 20-Deoxyingenol (20-DOI) in SCI and explored its potential mechanisms. We used a SCI rat model and evaluated the functional outcomes after the injury. Western blotting and immunofluorescence techniques were used to analyze the levels of mitophagy, apoptosis, and TFEB-related signaling pathways. Our research results show that 20-DOI significantly improves the apoptosis of neural cells after TBHP stimulation and functional recovery after spinal cord injury. In addition, mitophagy, TFEB levels, and apoptosis are related to the mechanism of 20-DOI treatment for spinal cord injury. Specifically, our research results indicate that 20-DOI restored the autophagic flux after injury, thereby inducing mitophagy, eliminating the accumulation of Cyto C, and inhibiting apoptosis. Further mechanism research suggests that 20-DOI may regulate mitophagy by promoting TFEB nuclear translocation. These results indicate that 20-DOI can significantly promote recovery after spinal cord injury, which may be a promising treatment method for spinal cord injury.

Crosstalk Between Cell Death and Spinal Cord Injury: Neurology and Therapy

Spinal cord injury (SCI) often leads to neurological dysfunction, and neuronal cell death is one of the main causes of neurological dysfunction. After SCI, in addition to necrosis, programmed cell death (PCD) occurs in nerve cells. At first, studies recognized only necrosis, apoptosis, and autophagy. In recent years, researchers have identified new forms of PCD, including pyroptosis, necroptosis, ferroptosis, and cuproptosis. Related studies have confirmed that all of these cell death modes are involved in various phases of SCI and affect the direction of the disease through different mechanisms and pathways. Furthermore, regulating neuronal cell death after SCI through various means has been proven to be beneficial for the recovery of neural function. In recent years, emerging therapies for SCI have also provided new potential methods to restore neural function. Thus, the relationship between SCI and cell death plays an important role in the occurrence and development of SCI. This review summarizes and generalizes the relevant research results on neuronal necrosis, apoptosis, autophagy, pyroptosis, necroptosis, ferroptosis, and cuproptosis after SCI to provide a new understanding of neuronal cell death after SCI and to aid in the treatment of SCI.

Sortilin inhibition in microglial cells cannot alleviate ischemia and hypoxia-induced neuronal injury in co-culture

Sortilin is a single-pass type I transmembrane protein which can bind to various cargo proteins, regulating their surface location, secretion, or degradation in lysosomes. In our previous study, we found that sortilin can regulate progranulin expression by transporting it to lysosomes and reduce neuronal cell injury in hypoxia-ischemia, but the expression and function of sortilin in microglial cells during hypoxia-ischemia are unknown. The purpose of this study was to further investigate the function of sortilin in microglial cells and its effect on neuron cells. In rat BV2 microglial cells, sortilin was knocked down by lentivirus. After oxygen-glucose deprivation/reperfusion (OGD/R), expression of sortilin, progranulin (PGRN) and JNK pathway was detected by western blot, immunofluorescence was used to show the localization of PGRN, secretion of TNFα/IL-6 was measured by Elisa. Then co-culture microglial cells with neuron cells during hypoxia-ischemia and detected the neuron injury by CCK-8 and TUNEL. The expression of sortilin, mature and cleaved PGRN were all increased after OGD/R in microglial cells. Furthermore, sortilin inhibition accompany with less PGRN localization in lysosomes and more mature and less cleaved PGRN expression in microglial cells. Sortilin inhibition also can reduce the inflammatory response in microglial cells, but it does not alleviate neuronal injury in co-culture. This study demonstrated that sortilin can regulate the expression of PGRN and reduce the inflammatory response in microglial cells. However, only inhibiting sortilin in microglial cells did not have an impact on the survival of neurons during ischemia-hypoxia.

The secretome of macrophages has a differential impact on spinal cord injury recovery according to the polarization protocol

Introduction

The inflammatory response after spinal cord injury (SCI) is an important contributor to secondary damage. Infiltrating macrophages can acquire a spectrum of activation states, however, the microenvironment at the SCI site favors macrophage polarization into a pro-inflammatory phenotype, which is one of the reasons why macrophage transplantation has failed.

Methods

In this study, we investigated the therapeutic potential of the macrophage secretome for SCI recovery. We investigated the effect of the secretome in vitro using peripheral and CNS-derived neurons and human neural stem cells. Moreover, we perform a pre-clinical trial using a SCI compression mice model and analyzed the recovery of motor, sensory and autonomic functions. Instead of transplanting the cells, we injected the paracrine factors and extracellular vesicles that they secrete, avoiding the loss of the phenotype of the transplanted cells due to local environmental cues.

Results

We demonstrated that different macrophage phenotypes have a distinct effect on neuronal growth and survival, namely, the alternative activation with IL-10 and TGF-β1 (M(IL-10+TGF-β1)) promotes significant axonal regeneration. We also observed that systemic injection of soluble factors and extracellular vesicles derived from M(IL-10+TGF-β1) macrophages promotes significant functional recovery after compressive SCI and leads to higher survival of spinal cord neurons. Additionally, the M(IL-10+TGF-β1) secretome supported the recovery of bladder function and decreased microglial activation, astrogliosis and fibrotic scar in the spinal cord. Proteomic analysis of the M(IL-10+TGF-β1)-derived secretome identified clusters of proteins involved in axon extension, dendritic spine maintenance, cell polarity establishment, and regulation of astrocytic activation.

Discussion

Overall, our results demonstrated that macrophages-derived soluble factors and extracellular vesicles might be a promising therapy for SCI with possible clinical applications.

Syringaresinol promotes the recovery of spinal cord injury by inhibiting neuron apoptosis via activating the ubiquitination factor E4B/AKT Serine/Threonine kinase signal pathway

Spinal cord injury (SCI) is a serious traumatic disease with no effective treatment. This study aimed to explore the therapeutic effect of syringaresinol on SCI. First, the potential targets and associated signaling pathways of syringaresinol were predicted by bioinformatics analysis and molecular docking. Second, MTT was employed to evaluate cell proliferation rate, Western blot was performed to detect protein expression, RT-qPCR was conducted to detect mRNA expression levels, flow cytometry and 5-ethynyl-2'-deoxyuridine (EDU) staining were used to determine cell apoptosis, and immunofluorescence and immunohistochemistry were used to estimate the expression of RNA binding fox-1 homolog 3 and clipped caspase 3. Basso-Beattie-Bresnahan scores and inclined plate tests were conducted to analyze hindlimb locomotor function. Results showed that syringaresinol could inhibit the apoptosis of glutamate-treated SHSY5Y cells by upregulating the expression of ubiquitination factor E4B (UBE4B) and activating the AKT serine/threonine kinase (AKT) signaling pathway. This effect can be rescued by UBE4B knockdown or AKT pathway inhibition. Syringaresinol remarkably improved locomotor function and increased neuronal survival in SCI rats. Our results suggested that syringaresinol could promote locomotor functional recovery by reducing neuronal apoptosis by activating the UBE4B/AKT signaling pathway.

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

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

The role of apoptosis in spinal cord injury: a bibliometric analysis from 1994 to 2023

Background

Apoptosis after spinal cord injury (SCI) plays a pivotal role in the secondary injury mechanisms, which cause the ultimate neurologic insults. A better understanding of the molecular and cellular basis of apoptosis in SCI allows for improved glial and neuronal survival via the administrations of anti-apoptotic biomarkers. The knowledge structure, development trends, and research hotspots of apoptosis and SCI have not yet been systematically investigated.

Methods

Articles and reviews on apoptosis and SCI, published from 1st January 1994 to 1st Oct 2023, were retrieved from the Web of Science™. Bibliometrix in R was used to evaluate annual publications, countries, affiliations, authors, sources, documents, key words, and hot topics.

Results

A total of 3,359 publications in accordance with the criterions were obtained, which exhibited an ascending trend in annual publications. The most productive countries were the USA and China. Journal of Neurotrauma was the most impactive journal; Wenzhou Medical University was the most prolific affiliation; Cuzzocrea S was the most productive and influential author. "Apoptosis," "spinal-cord-injury," "expression," "activation," and "functional recovery" were the most frequent key words. Additionally, "transplantation," "mesenchymal stemness-cells," "therapies," "activation," "regeneration," "repair," "autophagy," "exosomes," "nlrp3 inflammasome," "neuroinflammation," and "knockdown" were the latest emerging key words, which may inform the hottest themes.

Conclusions

Apoptosis after SCI may cause the ultimate neurological damages. Development of novel treatments for secondary SCI mainly depends on a better understanding of apoptosis-related mechanisms in molecular and cellular levels. Such therapeutic interventions involve the application of anti-apoptotic agents, free radical scavengers, as well as anti-inflammatory drugs, which can be targeted to inhibit core events in cellular and molecular injury cascades pathway.

Microarray analysis of lncRNAs and mRNAs in spinal cord contusion rats with iPSC-derived A2B5+ oligodendrocyte precursor cells transplantation

Spinal cord injury (SCI) is a severe complication of spinal trauma with high disability and mortality rates. Effective therapeutic methods to alleviate neurobehavioural deficits in patients with SCI are still lacking. In this study, we established a spinal cord contusion (SCC) model in adult Sprague Dawley rats. Induced pluripotent stem cell-derived A2B5+ oligodendrocyte precursor cells (iP-A2B5+OPCs) were obtained from mouse embryonic fibroblasts and injected into the lesion sites of SCC rats. Serological testing and magnetic resonance imaging were employed to determine the effect of iP-A2B5+OPCs cell therapy. The Basso-Beattie-Bresnahan score and inclined plane test were performed on days 1, 3, 7, and 14 after cell transplantation, respectively. Differentially expressed long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) were detected by microarray analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to analyse the biological functions of these lncRNAs and mRNAs. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to verify variations in the expression of crucial target genes. The results demonstrated that induced pluripotent stem cells exhibited embryonic stem cell-like morphology and could differentiate into diverse neural cells dominated by oligodendrocytes. The neurobehavioural performance of rats treated with iP-A2B5+OPCs transplantation was better than that of rats with SCC without cell transplantation. Notably, we found that 22 lncRNAs and 42 mRNAs were concurrently altered after cell transplantation, and the key lncRNA (NR_037671) and target gene (Cntnap5a) were identified in the iP-A2B5+OPCs group. Moreover, RT-qPCR revealed that iP-A2B5+OPCs transplantation reversed the downregulation of NR_037671 induced by SCC. Our findings indicated that iP-A2B5+OPCs transplantation effectively improves neurological function recovery after SCC, and the mechanism might be related to alterations in the expression of lncRNAs and mRNAs, such as NR_037671 and Cntnap5a.

Palmatine attenuates LPS-induced neuroinflammation through the PI3K/Akt/NF-κB pathway

To investigate the key molecular mechanisms of palmatine for the treatment of neuroinflammation through modulation of a pathway using molecular docking, molecular dynamics (MD) simulation combined with network pharmacology, and animal experiments. Five alkaloid components were obtained from the traditional Chinese medicine Huangteng through literature mining. Molecular docking and MD simulation with acetylcholinesterase were used to screen palmatine. At the animal level, mice were injected with LPS intracerebrally to cause a neuroinflammatory model, and the Morris water maze experiment was performed to examine the learning memory of mice. Anxiety levels were tested using the autonomous activity behavior experiment with the open field and elevated behavior experiments. HE staining and Niss staining were performed on brain tissue sections to observe morphological lesions and apoptosis; serum was examined for inflammatory factors TNF-α, IL-6, and IL-1β; Western blot was performed to detect the protein expression. The expression of PI3K/AKT/NFkB signaling pathway-related proteins was examined by Western blot. The results of network pharmacology showed that the screening of palmatine activation containing the PI3K/Akt/NFkB signaling pathway exerts antineuroinflammatory effects. Results from behavioral experiments showed that Pal enhanced learning memory in model mice, improved anxiety behavior, and significantly improved brain damage caused by neuroinflammation. The results of HE staining and Niss staining of brain tissue sections showed that palmatine could alleviate morphological lesions and nucleus damage in brain tissue. Palmatine improved the levels of serum inflammatory factors TNF-α, IL-6, and IL-1β. SOD, MDA, CAT, ACH, and ACHE in the hippocampus were improved. Western blot results showed that palmatine administration ameliorated LPS-induced neuroinflammation through the PI3K/Akt/NFkB pathway.

Harnessing the power of biological macromolecules in hydrogels for controlled drug release in the central nervous system: A review

Hydrogels have immense potential in revolutionizing central nervous system (CNS) drug delivery, improving outcomes for neurological disorders. They serve as promising tools for controlled drug delivery to the CNS. Available hydrogel types include natural macromolecules (e.g., chitosan, hyaluronic acid, alginate), as well as hybrid hydrogels combining natural and synthetic polymers. Each type offers distinct advantages in terms of biocompatibility, mechanical properties, and drug release kinetics. Design and engineering considerations encompass hydrogel composition, crosslinking density, porosity, and strategies for targeted drug delivery. The review emphasizes factors affecting drug release profiles, such as hydrogel properties and formulation parameters. CNS drug delivery applications of hydrogels span a wide range of therapeutics, including small molecules, proteins and peptides, and nucleic acids. However, challenges like limited biodegradability, clearance, and effective CNS delivery persist. Incorporating 3D bioprinting technology with hydrogel-based CNS drug delivery holds the promise of highly personalized and precisely controlled therapeutic interventions for neurological disorders. The review explores emerging technologies like 3D bioprinting and nanotechnology as opportunities for enhanced precision and effectiveness in hydrogel-based CNS drug delivery. Continued research, collaboration, and technological advancements are vital for translating hydrogel-based therapies into clinical practice, benefiting patients with CNS disorders. This comprehensive review article delves into hydrogels for CNS drug delivery, addressing their types, design principles, applications, challenges, and opportunities for clinical translation.

GPNMB Modulates Autophagy to Enhance Functional Recovery After Spinal Cord Injury in Rats

Spinal cord injury (SCI) severely affects the quality of life and autonomy of patients, and effective treatments are currently lacking. Autophagy, an essential cellular metabolic process, plays a crucial role in neuroprotection and repair after SCI. Glycoprotein non-metastatic melanoma protein B (GPNMB) has been shown to promote neural regeneration and synapse reconstruction, potentially through the facilitation of autophagy. However, the specific role of GPNMB in autophagy after SCI is still unclear. In this study, we utilized the spinal cord transection method to establish SCI rats model and overexpressed GPNMB using adenoviral vectors. We assessed tissue damage using hematoxylin and eosin (H&E) and Nissl staining, and observed cell apoptosis using TUNEL staining. We evaluated the inflammatory response by measuring inflammatory factors using enzyme-linked immunosorbent assay (ELISA). In addition, we measured reactive oxygen species (ROS) levels using 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), and assessed oxidative stress levels by measuring malondialdehyde (MDA) and glutathione (GSH) using ELISA. To evaluate autophagy levels, we performed immunofluorescence staining for the autophagy marker Beclin-1 and conducted Western blot analysis for autophagy-related proteins. We also assessed limb recovery through functional evaluation. Meanwhile, we induced cell injury using lipopolysaccharide (LPS) and added an autophagy inhibitor to verify the impact of GPNMB on SCI through autophagy modulation. The results demonstrated that GPNMB alleviated the inflammatory response, reduced oxidative stress levels, inhibited cell apoptosis, and promoted autophagy following SCI. Inhibiting autophagy reversed the effects of GPNMB. These findings suggest that GPNMB promotes neural injury repair after SCI, potentially through attenuating the inflammatory response, reducing oxidative stress, and inhibiting cell apoptosis.

Progranulin and GPNMB: interactions in endo-lysosome function and inflammation in neurodegenerative disease

BACKGROUND

Alterations in progranulin (PGRN) expression are associated with multiple neurodegenerative diseases (NDs), including frontotemporal dementia (FTD), Alzheimer's disease (AD), Parkinson's disease (PD), and lysosomal storage disorders (LSDs). Recently, the loss of PGRN was shown to result in endo-lysosomal system dysfunction and an age-dependent increase in the expression of another protein associated with NDs, glycoprotein non-metastatic B (GPNMB).

MAIN BODY

It is unclear what role GPNMB plays in the context of PGRN insufficiency and how they interact and contribute to the development or progression of NDs. This review focuses on the interplay between these two critical proteins within the context of endo-lysosomal health, immune function, and inflammation in their contribution to NDs.

SHORT CONCLUSION

PGRN and GPNMB are interrelated proteins that regulate disease-relevant processes and may have value as therapeutic targets to delay disease progression or extend therapeutic windows.

IRE1α protects against osteoarthritis by regulating progranulin-dependent XBP1 splicing and collagen homeostasis

Osteoarthritis (OA) is a full-joint, multifactorial, degenerative and inflammatory disease that seriously affects the quality of life of patients due to its disabling and pain-causing properties. ER stress has been reported to be closely related to the progression of OA. The inositol-requiring enzyme 1α/X-box-binding protein-1 spliced (IRE1α/XBP1s) pathway, which is highly expressed in the chondrocytes of OA patients, promotes the degradation and refolding of abnormal proteins during ER stress and maintains the stability of the ER environment of chondrocytes, but its function and the underlying mechanisms of how it contributes to the progression of OA remain unclear. This study investigates the role of IRE1α/ERN1 in OA. Specific deficiency of ERN1 in chondrocytes spontaneously resulted in OA-like cartilage destruction and accelerated OA progression in a surgically induced arthritis model. Local delivery of AdERN1 relieved degradation of the cartilage matrix and prevented OA development in an ACLT-mediated model. Mechanistically, progranulin (PGRN), an intracellular chaperone, binds to IRE1α, promoting its phosphorylation and splicing of XBP1u to generate XBP1s. XBP1s protects articular cartilage through TNF-α/ERK1/2 signaling and further maintains collagen homeostasis by regulating type II collagen expression. The chondroprotective effect of IRE1α/ERN1 is dependent on PGRN and XBP1s splicing. ERN1 deficiency accelerated cartilage degeneration in OA by reducing PGRN expression and XBP1s splicing, subsequently decreasing collagen II expression and triggering collagen structural abnormalities and an imbalance in collagen homeostasis. This study provides new insights into OA pathogenesis and the UPR and suggests that IRE1α/ERN1 may serve as a potential target for the treatment of joint degenerative diseases, including OA.

FHL2 regulates microglia M1/M2 polarization after spinal cord injury via PARP14-depended STAT1/6 pathway

Neuronal apoptosis and inflammation exacerbate the secondary injury after spinal cord injury (SCI). Four and a half domains 2 (FHL2) is a multifunctional scaffold protein with tissue- and cell-type specific effects on the regulation of inflammation, but its role in SCI remains unclear. The T10 mouse spinal cord contusion model was established, and the mice were immediately injected with lentiviruses carrying FHL2 shRNA after SCI. The results showed that FHL2 expression was increased following SCI, and then gradually decreased. Moreover, FHL2 depletion aggravated functional impairment, neuronal necrosis, and enlarged lesion cavity areas in the injured spinal cord. FHL2 deficiency facilitated neuronal apoptosis by elevating cleaved caspase 3/9 expression, neuroinflammation by regulating microglia polarization, and bone loss. Indeed, FHL2 deficiency increased the secretion of TNF-α and IL-6, M1 microglia polarization, and the activation of STAT1 pathway but decreased the secretion of IL-10 and IL-4, M2 microglia polarization, and the activation of the STAT6 pathway in the spinal cord. In vitro, FHL2 silencing promoted LPS + IFN-γ-induced microglia M1 polarization through activating the STAT1 pathway and alleviated IL-4-induced microglia M2 polarization via inhibiting the STAT6 pathway. FHL2 positively regulated the expression of poly (ADP-ribose) polymerase family member 14 (PARP14) by promoting its transcription. PARP14 overexpression inhibited FHL2 silencing-induced microglia M1 polarization and relieved the inhibitory effect of FHL2 silencing on microglia M2 polarization. Collectively, the study suggests that FHL2 reduces the microglia M1/M2 polarization-mediated inflammation via PARP14-dependent STAT1/6 pathway and thereby improves functional recovery after SCI.

Long-term oral tribasic copper chloride exposure impedes cognitive function and disrupts mitochondrial metabolism by inhibiting mitophagy in rats

Copper (Cu) is an essential micronutrient element that commonly acted as a feed additive and antimicrobial in agricultural production. Tribasic copper chloride (TBCC) is a relatively new dietary Cu source, and its exposure directly or indirectly affects the safety of animals and ecological environment, thus posing a potential risk to human health. Cu overexposure would produce toxic reactive oxygen species (ROS) that may have toxic effects on the host, but the mechanism of neurotoxicity remains unclear. Herein, to explore the effects of long-term TBCC-induced neurotoxicity, 150 male Sprague-Dawley rats were randomly allocated and treated with different doses of TBCC, and the cortical and hippocampus tissues were harvested at 0, 6, and 12 weeks after treatment. Morris Water Maze (MWM) test showed that excessive intake of TBCC could induce cognitive dysfunction in rats. Moreover, after treatment with 160 mg/kg Cu (276 mg/kg TBCC) for 12 weeks, pathological changes were observed in the cortex and hippocampus, and the number of Nissl bodies decreased significantly in the hippocampus. Additionally, mitochondrial structure was significantly altered and neuronal mitochondrial fusion/fission equilibrium was disrupted in 80 mg/kg and 160 mg/kg Cu groups at 12 weeks. With an increase in TBCC dose and treatment time, the number of mitophagosomes and the expression of mitophagy-related genes were significantly decreased after initially increasing. Furthermore, metformin (Met) and 3-methyladenine (3-MA) were used to regulate the level of mitophagy to further explore the mechanism of Cu-induced nerve cell injury in vitro., and it found that mitophagy activator (Met) would increase mitochondrial fission, while mitophagy inhibitors (3-MA) would aggravate mitochondrial metabolic disorders by promoting mitochondrial fusion and inhibiting mitochondrial division. These results indicate that long-term oral TBCC could impede cognitive function and disrupts mitochondrial metabolism by inhibiting mitophagy, providing an insightful perspective on the neurotoxicity of dietary TBCC.

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

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

The Role of Progranulin (PGRN) in the Pathogenesis of Ischemic Stroke

Stroke is a life-threatening medical condition and is a leading cause of disability. Cerebral ischemia is characterized by a distinct inflammatory response starting with the production of various cytokines and other inflammation-related agents. Progranulin (PGRN), a multifunctional protein, is critical in diverse physiological reactions, such as cell proliferation, inflammation, wound healing, and nervous system development. A mature PGRN is anti-inflammatory, while granulin, its derivative, conversely induces pro-inflammatory cytokine expression. PGRN is significantly involved in the brain tissue and its damage, for example, improving mood and cognitive disorders caused by cerebral ischemia. It may also have protective effects against nerve and spinal cord injuries by inhibiting neuroinflammatory response and apoptosis or it may be related to the proliferation, accumulation, differentiation, and activation of microglia. PGRN is a neurotrophic factor in the central nervous system. It may increase post-stroke neurogenesis of the subventricular zone (SVZ), which is particularly important in improving long-term brain function following cerebral ischemia. The neurogenesis enhanced via PGRN in the ischemic brain SVZ may be attributed to the induction of PI3K/AKT and MAPK/ERK signaling routes. PGRN can also promote the proliferation of neural stem/progenitor cells through PI3K/AKT signaling pathway. PGRN increases hippocampal neurogenesis, reducing anxiety and impaired spatial learning post-cerebral ischemia. PGRN alleviates cerebral ischemia/reperfusion injury by reducing endoplasmic reticulum stress and suppressing the NF-κB signaling pathway. PGRN can be introduced as a potent neuroprotective agent capable of improving post-ischemia neuronal actions, mainly by reducing and elevating the inflammatory and anti-inflammatory cytokines. Expression, storage, cleavage, and function of progranulin (PGRN) in the pathogenesis of ischemic stroke.

Bone marrow mesenchymal stem cell exosomes-derived microRNA-216a-5p on locomotor performance, neuronal injury, and microglia inflammation in spinal cord injury

Background: MicroRNA-216a-5p (miR-216a-5p) mediates inflammatory responses and neuronal injury to participate in the pathology of spinal cord injury (SCI). This study intended to explore the engagement of bone marrow mesenchymal stem cell exosomes (BMSC-Exo)-derived miR-216a-5p in locomotor performance, neuronal injury, and microglia-mediated inflammation in SCI rats. Methods: Rat BMSC or BMSC-Exo was injected into SCI rats. GW4869 treatment was adopted to suppress the exosome secretion from BMSC. Subsequently, miR-216a-5p-overexpressed BMSC-Exo (BMSC-miR-Exo) or negative-control-overexpressed BMSC-Exo (BMSC-NC-Exo) were injected into SCI rats. Results: The injection of BMSC or BMSC-Exo enhanced locomotor performance reflected by Basso, Beattie & Bresnahan score (p < 0.001), and neuronal viability reflected by NeuN+ cells (p < 0.01), but attenuated neuronal apoptosis reflected by TUNEL positive rate, cleaved-caspase-3 expression, and B-cell leukemia/lymphoma-2 expression (p < 0.05). Additionally, the injection of BMSC or BMSC-Exo suppressed microglia M1 polarization-mediated inflammation reflected by IBA1+iNOS+ cells, tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 (p < 0.01). Notably, the effect of BMSC on the above functions was retarded by the GW4869 treatment (most p < 0.05). Subsequently, the injection of BMSC-miR-Exo further improved locomotor performance (p < 0.05), while inhibiting neuronal apoptosis (p < 0.05) and microglia M1 polarization-mediated inflammation (p < 0.05) compared to BMSC-NC-Exo. Interestingly, the injection of BMSC-miR-Exo reduced toll-like receptor 4 (TLR4) (p < 0.01), myeloid differentiation factor 88 (p < 0.05), and nuclear factor kappa B (NF-κB) (p < 0.05) expressions versus BMSC-NC-Exo. Conclusion: BMSC-Exo-derived miR-216a-5p enhances functional recovery by attenuating neuronal injury and microglia-mediated inflammation in SCI, which may be attributable to its inhibition of the TLR4/NF-κB pathway.

Inhibition of complement C3 signaling ameliorates locomotor and visual dysfunction in autoimmune inflammatory diseases

Neuromyelitis optica (NMO) is an autoimmune inflammatory disease of the central nervous system (CNS) characterized by transverse myelitis and optic neuritis. The pathogenic serum IgG antibody against the aquaporin-4 (AQP4) on astrocytes triggers the activation of the complement cascade, causing astrocyte injury, followed by oligodendrocyte injury, demyelination, and neuronal loss. Complement C3 is positioned as a central player that relays upstream initiation signals to activate downstream effectors, potentially stimulating and amplifying host immune and inflammatory responses. However, whether targeting the inhibition of C3 signaling could ameliorate tissue injury, locomotor defects, and visual impairments in NMO remains to be investigated. In this study, using the targeted C3 inhibitor CR2-Crry led to a significant decrease in complement deposition and demyelination in both slice cultures and focal intracerebral injection models. Moreover, the treatment downregulated the expression of inflammatory cytokines and improved motor dysfunction in a systemic NMO mouse model. Similarly, employing serotype 2/9 adeno-associated virus (AAV2/9) to induce permanent expression of CR2-Crry resulted in a reduction in visual dysfunction by attenuating NMO-like lesions. Our findings reveal the therapeutic value of inhibiting the complement C3 signaling pathway in NMO.

Progranulin promoted the proliferation, metastasis, and suppressed apoptosis via JAK2-STAT3/4 signaling pathway in papillary thyroid carcinoma

BACKGROUND

Progranulin (PGRN), a glycoprotein secreted by a wide range of epithelial cells and plays an important role in inflammatory mechanisms and tumor progression. In this study, the expression, and functions of PGRN in papillary thyroid carcinoma (PTC) was examined to explore the potential pathogenesis of PTC.

METHODS

Western blotting and qRT-PCR were used to detect the relationship between PGRN expression and clinicopathological characteristics of patients with PTC. PTC cell lines with PGRN overexpression and with PGRN knockdown were established to explore their effects on the biological behavior. Western blotting was used to detect the changes of relevant molecules and JAK2-STAT3/4 signaling pathway. Moreover, rescue experiments validated the involvement of the JAK2-STAT3/4 signaling pathway. And statistical analyses were analyzed using SPASS 21.0 and graph generation were performed using GraphPad Prism 8.0.

RESULTS

PGRN was overexpressed in PTC tissue and increased by 75% at mRNA level and 161% at relative protein level in the patients with lymph node metastasis compared to without lymph node metastasis. Besides, PGRN regulated and promoted PTC cell proliferation, migration, invasion, and inhibited cell apoptosis. With PGRN overexpressed, relevant molecules including the expression of BCL2/BAX, BCL2/BAD, CyclinD1, MMP2, vimentin and N-cadherin were increased, the expression level of E-cadherin was decreased, and the phosphorylation of JAK2 and STAT3/4 were increased. JAK inhibitor (JSI-124) rescued these changes of PTC cells induced by overexpressed PGRN.

CONCLUSIONS

These findings revealed that PGRN promote the progression of PTC through the JAK2-STAT3/4 pathway, and PGRN could be served as a potential therapeutic target for PTC.

Identification of Cathepsin B as a Therapeutic Target for Ferroptosis of Macrophage after Spinal Cord Injury

Hemorrhage and immune cell infiltration are the main pathological features of spinal cord injury (SCI). Excessive iron deposition is caused by leaking hemosiderin which may over-activate ferroptosis pathways, resulting in lipid peroxidation and mitochondrial dysfunction in cells. Inhibiting ferroptosis after SCI has been shown to aid functional recovery. However, the essential genes involved in cellular ferroptosis following SCI are still unknown. Here we show that Ctsb is a statistical significance gene by collecting multiple transcriptomic profiles and identifying differentially expressed ferroptosis-related genes, which are abundantly expressed in myeloid cells after SCI and widely distributed at the epicenter of the injury. The expression score of ferroptosis, calculated by ferroptosis driver/suppressor genes, was high in macrophages. Furthermore, we discovered that inhibiting cathepsin B (CTSB), specifically with a small-molecule drug, CA-074-methyl ester (CA-074-me), reduced lipid peroxidation and mitochondrial dysfunction in macrophages. We also found that alternatively activated M2-polarized macrophages are more susceptible to hemin-induced ferroptosis. Consequently, CA-074-me could reduce ferroptosis, induce M2 macrophage polarization, and promote the neurological function recovery of mice after SCI. Our study comprehensively analyzed the ferroptosis after SCI from the perspective of multiple transcriptomes and provided a novel molecular target for SCI treatment.

Different Ways to Die: Cell Death Pathways and Their Association With Spinal Cord Injury

Cell death is a systematic/nonsystematic process of cessation of normal morphology and functional properties of the cell to replace and recycle old cells with new also promoting inflammation in some cases. It is a complicated process comprising multiple pathways. Some are well-explored, and others have just begun to be. The research on appropriate control of cell death pathways after acute and chronic damage of neuronal cells is being widely researched today due to the lack of regeneration and recovering potential of a neuronal cell after sustaining damage and the inability to control the direction of neuronal growth. In the progression and onset of various neurological diseases, impairments in programmed cell death signaling processes, like necroptosis, apoptosis, ferroptosis, pyroptosis, and pathways directly or indirectly linked, like autophagy as in nonprogrammed necrosis, are observed. Spinal cord injury (SCI) involves the temporary or permanent disruption of motor activities due to the death of a neuronal and glial cell in the spinal cord accompanied by axonal degeneration. Recent years have seen a significant increase in research on the intricate biochemical interactions that occur after a SCI. Different cell death pathways may significantly impact the subsequent damage processes that lead to the eventual neurological deficiency after an injury to the spinal cord. A better knowledge of the molecular basis of the involved cell death pathways might help enhance neuronal and glial survival and neurological deficits, promoting a curative path for SCI.

Organokines in COVID-19: A Systematic Review

Coronavirus disease 2019 (COVID-19) is a viral infection caused by SARS-CoV-2 that induces a generalized inflammatory state. Organokines (adipokines, osteokines, myokines, hepatokines, and cardiokines) can produce beneficial or harmful effects in this condition. This study aimed to systematically review the role of organokines on COVID-19. PubMed, Embase, Google Scholar, and Cochrane databases were searched, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and 37 studies were selected, comprising more than 2700 individuals infected with the virus. Among COVID-19 patients, organokines have been associated with endothelial dysfunction and multiple organ failure due to augmented cytokines and increased SARS-CoV-2 viremia. Changes in the pattern of organokines secretion can directly or indirectly contribute to aggravating the infection, promoting immune response alterations, and predicting the disease progression. These molecules have the potential to be used as adjuvant biomarkers to predict the severity of the illness and severe outcomes.

Gelatin methacryloyl hydrogel scaffold loaded with activated Schwann cells attenuates apoptosis and promotes functional recovery following spinal cord injury

Spinal cord injury (SCI) is a refractory disease of the central nervous system with a high disability and incidence rate. In recent years, bioactive material combined with cell transplantation has been considered an effective method for the treatment of SCI. The present study encapsulated activated Schwann cells (ASCs) in a 3D gelatin methacryloyl (GelMA) hydrogel in order to investigate its therapeutic effects on SCI. ASCs were isolated from previously ligated rat sciatic nerves. Scanning electron microscopy and live/dead staining were used to evaluate the biocompatibility of hydrogels with the ASCs. The scaffold was transplanted into the spinal cord of rats in the hemisection model. Behavioral tests and hematoxylin and eosin staining were employed to assess the locomotion recovery and lesion areas before and after treatment. Cell apoptosis was evaluated using TUNEL staining and immunochemistry, and apoptosis-related protein expression was detected using western blot analysis. The ASCs exhibited a favorable survival and proliferative ability in the 3D GelMA hydrogel. The scaffold transplantation significantly reduced the cavities and improved functional recovery. Moreover, the GelMA/ASCs implants significantly inhibited cell apoptosis following SCI and this effect may be mediated via the p38 MAPK pathway. Overall, these findings indicated that ASCs combined with the 3D GelMA hydrogel may be a promising therapeutic strategy for SCI.

Sodium houttuyfonate exerts its neuroprotection effect by inhibiting the M1 microglia polarization in a TLR4/NF-κB signal pathway

Neuroinflammation plays an important role in secondary injury after spinal cord injury (SCI) and may aggravate neurological dysfunction. Several studies have indicated that sodium houttuyfonate (SH) can significantly inhibit macrophage- mediated inflammation; however, its effects on SCI still needs to be elucidated. We found that SH improved Basso, Beattie, and Bresnahan scores and performance in the inclined plane test of SCI model rats. The injured spinal cord exhibited less neuronal loss, cell apoptosis, and M1 microglial polarization after SH treatment. In vitro, SH reduced TLR4/NF-κB expression in cultured primary microglia and decreased M1 microglial polarization and cell apoptosis in a lipopolysaccharide (LPS)-pretreated microglia and neuron coculture system. These results indicated that SH may exert a neuroprotective effect by inhibiting M1 microglial polarization after SCI via the TLR4/NF-κB signalling pathway.

Role of inflammation in neurological damage and regeneration following spinal cord injury and its therapeutic implications

Spinal cord injury (SCI) is an incurable trauma that frequently results in partial or complete loss of motor and sensory function. Massive neurons are damaged after the initial mechanical insult. Secondary injuries, which are triggered by immunological and inflammatory responses, also result in neuronal loss and axon retraction. This results in defects in the neural circuit and a deficiency in the processing of information. Although inflammatory responses are necessary for spinal cord recovery, conflicting evidence of their contributions to specific biological processes have made it difficult to define the specific role of inflammation in SCI. This review summarizes our understanding of the complex role of inflammation in neural circuit events following SCI, such as cell death, axon regeneration and neural remodeling. We also review the drugs that regulate immune responses and inflammation in the treatment of SCI and discuss the roles of these drugs in the modulation of neural circuits. Finally, we provide evidence about the critical role of inflammation in facilitating spinal cord neural circuit regeneration in zebrafish, an animal model with robust regenerative capacity, to provide insights into the regeneration of the mammalian central nervous system.

Double-target neural circuit-magnetic stimulation improves motor function in spinal cord injury by attenuating astrocyte activation

Multi-target neural circuit-magnetic stimulation has been clinically shown to improve rehabilitation of lower limb motor function after spinal cord injury. However, the precise underlying mechanism remains unclear. In this study, we performed double-target neural circuit-magnetic stimulation on the left motor cortex and bilateral L5 nerve root for 3 successive weeks in a rat model of incomplete spinal cord injury caused by compression at T10. Results showed that in the injured spinal cord, the expression of the astrocyte marker glial fibrillary acidic protein and inflammatory factors interleukin 1β, interleukin-6, and tumor necrosis factor-α had decreased, whereas that of neuronal survival marker microtubule-associated protein 2 and synaptic plasticity markers postsynaptic densification protein 95 and synaptophysin protein had increased. Additionally, neural signaling of the descending corticospinal tract was markedly improved and rat locomotor function recovered significantly. These findings suggest that double-target neural circuit-magnetic stimulation improves rat motor function by attenuating astrocyte activation, thus providing a theoretical basis for application of double-target neural circuit-magnetic stimulation in the clinical treatment of spinal cord injury.

Application of natural antioxidants from traditional Chinese medicine in the treatment of spinal cord injury

Spinal cord injury (SCI) is a devastating central nervous system disease, caused by physical traumas. With the characteristic of high disability rate, catastrophic dysfunction, and enormous burden on the patient’s family, SCI has become a tough neurological problem without efficient treatments. Contemporarily, the pathophysiology of SCI comprises complicated and underlying mechanisms, in which oxidative stress (OS) may play a critical role in contributing to a cascade of secondary injuries. OS substantively leads to ion imbalance, lipid peroxidation, inflammatory cell infiltration, mitochondrial disorder, and neuronal dysfunction. Hence, seeking the therapeutic intervention of alleviating OS and appropriate antioxidants is an essential clinical strategy. Previous studies have reported that traditional Chinese medicine (TCM) has antioxidant, anti-inflammatory, antiapoptotic and neuroprotective effects on alleviating SCI. Notably, the antioxidant effects of some metabolites and compounds of TCM have obtained numerous verifications, suggesting a potential therapeutic strategy for SCI. This review aims at investigating the mechanisms of OS in SCI and highlighting some TCM with antioxidant capacity used in the treatment of SCI.

Granulin as an important immune molecule involved in lamprey tissue repair and regeneration by promoting cell proliferation and migration

Progranulin (PGRN) is an autocrine growth factor that regulates cell proliferation, migration, wound healing, and tissue repair in mammals. Lamprey is the most primitive of the extant vertebrates and is regarded as the survivor of a once flourishing group of paleozoic vertebrates, with a history of more than 500 million years. To date, the evolutionary dynamics and the underlying function of the PGRNs remain largely unclear in lamprey. Here, we screened four genes encoding PGRNs from the genomes of Lethenteron reissneri and Petromyzon marinus, including one long form (named Lr-PGRN-L) and three short forms (named Lr-PGRN-S1, Lr-PGRN-S2, and Lr-PGRN-S3), and performed phylogenetic tree, functional domain, and synteny analyses to identify the evolutionary history of the four Lr-PGRNs. In addition, the expressions of the four Lr-pgrn family genes and the immune response against various pathogenic challenges were also investigated. We found that these genes were widely distributed in various tissues of lamprey and performed a variety of functions. Moreover, our results suggest that Lr-PGRN-S1 induces cell migration and proliferation, and is involved in repair after skin and spinal cord injury under appropriate conditions. Our findings are valuable because they improve the understanding of the evolutionary relationship of vertebrate pgrn genes, as well as providing new insights into the diverse and important roles of Lr-PGRNs.

An anti-inflammatory and neuroprotective biomimetic nanoplatform for repairing spinal cord injury

Spinal cord regeneration after a spinal cord injury (SCI) remains a difficult challenge due to the complicated inflammatory microenvironment and neuronal damage at the injury sites. In this study, retinoic acid (RA) and curcumin (Cur) were co-loaded with bovine serum albumin (BSA) self-assembly to obtain RA@BSA@Cur nanoparticles (NPs) for SCI treatment. Cur, as an antioxidant drug, facilitated reactive oxygen species (ROS) scavenging, and decreased the amount of inflammatory factors secreted by macrophages, while RA could enhance neurite extensions and neural differentiation. The constructed RA@BSA@Cur NPs not only induced polarization of macrophages toward pro-regenerative phenotypes and markedly reduced the inflammatory response of macrophages or microglia, but also increased neurite length in PC12 cells and neuronal differentiation of bone marrow mesenchymal stem cells, improved the differentiation of neural stem cells (NSCs) into β3-tubulin⁺ neurons, and reversed the pro-astrocyte differentiation effect of inflammatory cytokines on NSCs. In vivo experiments revealed that RA@BSA@Cur NPs regulated the phenotypic polarization of macrophages, inhibited the release of inflammatory mediators, promoted functional neuron regeneration and motor function, and further inhibited scar tissue formation. This study highlighted that the BSA-based biomimetic nanomaterials could be used as ROS scavengers and nerve regeneration promoters for treating SCI.

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Retinoic acid and Curcumin with remarkable neuroprotective and antioxidant activities are prepared for spinal cord injury.

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RA@BSA@Cur NPs induce polarization of macrophages, reduce levels of tumor necrosis factor-α and interleukin-6, and thus reduce the inflammatory response.

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RA@BSA@Cur NPs increase neurite length in PC12 cells and neuronal differentiation of bone marrow mesenchymal stem cells, and regulate the neurons/astrocytes differentiation of NSCs.

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RA@BSA@Cur NPs reverse the pro-astrocyte differentiation effect of macrophages-derived inflammatory cytokines on NSCs.

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RA@BSA@Cur NPs promote neuron regeneration and motor function, inhibit scar tissue formation, and regulate the phenotypic polarization of macrophages.

Progranulin Promotes Functional Recovery in Rats with Acute Spinal Cord Injury via Autophagy-Induced Anti-inflammatory Microglial Polarization

Since microglia-associated neuroinflammation plays a critical role in the progression of acute spinal cord injury, modulation of microglial activation has been suggested as a potential therapeutic strategy. Progranulin has been reported to exert neuroprotective effects by attenuating neuroinflammation, but whether these effects are due to the modulation of microglial polarization and the underlying mechanism remain unclear. Here, we investigated the effect of progranulin on microglial polarization and analyzed the crosstalk between microglial autophagy and polarization. We found that progranulin could reduce proinflammatory cytokine production at the lesion site and promote locomotor functional recovery after acute spinal cord injury. In vitro, we found that progranulin could activate microglia to acquire an anti-inflammatory phenotype and express IL-10. Moreover, progranulin-mediated enhancement of anti-inflammatory microglial polarization was attributed to the protection of lysosomal function and the enhancement of autophagic flux. Above all, progranulin exerts anti-inflammatory effects by protecting lysosomal function to enhance microglial autophagy, induce M2 microglial polarization, and ultimately improve neurological function after acute spinal cord injury. These results suggest that targeting the autophagy-lysosomal pathway to modulate microglial polarization and reduce neuroinflammation is a potential treatment for spinal cord injury.

Vagus Nerve Stimulation Reduces Neuroinflammation Through Microglia Polarization Regulation to Improve Functional Recovery After Spinal Cord Injury

Background

Spinal cord injury (SCI) is a devastating disease that lacks effective treatment. Interestingly, recent studies indicated that vagus nerve stimulation (VNS), neuromodulation that is widely used in a variety of central nervous system (CNS) diseases, improved motor function recovery after SCI. But the exact underlying mechanism of how VNS ameliorates SCI is unclear. This study aimed to confirm the efficacy and further explore the potential therapeutic mechanism of VNS in SCI.

Method

A T10 spinal cord compression model was established in adult female Sprague-Dawley rats. Then the stimulation electrode was placed in the left cervical vagus nerve (forming Sham-VNS, VNS, and VNS-MLA groups). Basso-Beattie-Bresnahan (BBB) behavioral scores and Motor evoked potentials (MEPs) analysis were used to detect motor function. A combination of histological and molecular methods was used to clarify the relevant mechanism.

Results

Compared with the Sham-VNS group, the VNS group exhibited better functional recovery, reduced scar formation (both glial and fibrotic scars), tissue damage, and dark neurons, but these beneficial effects of VNS were diminished after alpha 7 nicotinic acetylcholine receptor (α7nAchR) blockade. Specifically, VNS inhibited the pro-inflammatory factors TNF-α, IL-1β, and IL-6 and increased the expression of the anti-inflammatory factors IL-10. Furthermore, we found that VNS promotes the shift of M1-polarized Iba-1+/CD86+ microglia to M2-polarized Iba-1+/CD206+ microglia via upregulating α7nAchR to alleviate neuroinflammation after SCI.

Conclusion

Our results demonstrated that VNS promotes microglial M2 polarization through upregulating α7nAChR to reduce neuroinflammation, thus improving motor function recovery after SCI. These findings indicate VNS might be a promising neuromodulation strategy for SCI.

Progranulin deficiency promotes persistent neuroinflammation and causes regional pathology in the hippocampus following traumatic brain injury

Traumatic brain injury (TBI) can be progressive and can lead to the development of a long-term complication termed chronic traumatic encephalopathy. The mechanisms underlying the progressive changes are still unknown; however, studies have suggested that microglia-mediated neuroinflammation in response to TBI may play a fundamental role. This study aimed to determine whether progranulin (PGRN), a major modulator of microglial activity, plays a role in the progressive damage following TBI. PGRN-deficient and wild-type mice were subjected to controlled cortical impact and were observed neuropathologically after 3 days, 7 days, and 5 months. Compared to sham and wild-type mice, the PGRN-deficient mice showed overall stronger microgliosis and astrocytosis. The astrocytosis involved broader areas than the microgliosis and was more prominent in the basal ganglia, hippocampus, and internal capsule in PGRN-deficient mice. Ongoing neuronal death was uniquely observed in the hippocampal CA3 region of PGRN-deficient mice at 5 months after TBI, accompanying the regional chronic microgliosis and astrocytosis involving the CA3 commissural pathway. In addition, there was M1 microglial polarization in the pericontusional area with activated TLR4/MyD88/NF-κB signaling; however, the hippocampus showed only mild M1 polarization 7 days after TBI. Lastly, Morris water maze tests showed PGRN-deficient mice had poorer spatial learning and memory 5 months after TBI than wild-type or sham mice. The data indicated the PGRN deficiency caused TBI progression by promoting persistent microgliosis with microglial polarization and astrocytosis, as well as regional pathology in the hippocampus. The study suggests that PGRN should be evaluated as a potential therapy for TBI.

Elucidating the Potential Mechanisms Underlying Distraction Spinal Cord Injury-Associated Neuroinflammation and Apoptosis

The incidence of distraction spinal cord injury (DSCI), which results from spinal cord ischemia due to vascular compromise and spinal cord tract disturbances, remains high. Furthermore, because no ideal animal model that mimics DSCI in clinical settings is available thus far, the related molecular mechanisms underlying DSCI remain unclear. Thus, this study aimed to establish a porcine model of DSCI and investigate the neuroinflammation and apoptosis mechanisms in these pigs. Before surgery, all pigs were randomly divided into three groups: sham group, osteotomy surgery only; the incomplete distraction spinal cord injury (IDSCI) and complete distraction spinal cord injury (CDSCI) group, osteotomy plus DSCI surgery with a motor-evoked potential (MEP) amplitude decreased by approximately 75% and 100%, respectively. After surgery, modified Tarlov scoring and MRC muscle strength scoring were used to evaluate neurologic function in each group. We observed the distracted spinal cord using MRI, and then all pigs were sacrificed. Inflammatory cytokine levels in the spinal cord and cerebrospinal fluid (CSF) were also analyzed. We used immunofluorescence staining to assess the neuronal and microglial structure and function and astrocyte hyperplasia in the central DSCI lesions (T15). Western blotting was used to determine the expression of apoptosis-related proteins. Results showed that the modified Tarlov scoring and muscle strength decreased significantly in the two DSCI groups. T2-MRI showed a relative enhancement at the center of the DSCI lesions. H&E and Lxol fast blue staining revealed that spinal cord distraction destroyed the normal structure of spinal cord tissues and nerve fiber tracts, exacerbating inflammatory cell infiltration, hyperemia, and edema. The IL-1β, IL-6, and TNF-α levels increased in the spinal cord and CSF following DSCI. Immunofluorescence staining results indicated the GFAP, Iba-1 expression increased following DSCI, whereas the NeuN expression reduced. Moreover, DSCI promoted the protein expression of P53, Bcl-2-associated X protein (Bax), and Caspase-3 in the spinal cord tissues, whereas it reduced the Bcl-2 expression. This study successfully established a porcine DSCI model that closely mimics DSCI in clinical settings, and clarified the mechanisms underlying DSCI-associated neuroinflammation and apoptosis; thus, our findings highlight potential DSCI-treatment strategies for further establishing suitable drug therapies.

Blockage of ERCC6 Alleviates Spinal Cord Injury Through Weakening Apoptosis, Inflammation, Senescence, and Oxidative Stress

Objective: Spinal cord injury (SCI) is a devastating disease resulting in lifelong disability, but the molecular mechanism remains unclear. Our study was designed to observe the role of excision repair cross-complementing group 6 (ERCC6) following SCI and to determine the underlying mechanism.

Methods: SCI mouse models and LPS-induced microglia cell models were established. ERCC6 expression was blocked by ERCC6-siRNA-carrying lentivirus. Nissl staining was utilized for detecting neuronal damage, and apoptosis was analyzed with TUNEL and Western blotting (apoptotic markers). Immunofluorescence was used for measuring macrophage markers (CD68 and F4/80) and astrocyte and microglia markers (GFAP and Iba-1). Pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) were measured via ELISA. Senescent cells were estimated via SA-β-Gal staining as well as Western blot (senescent markers p21 and p27). Oxidative stress was investigated by detecting the expression of 4-HNE, Nrf2, and Keap1, and intracellular ROS levels.

Results: ERCC6 expression was remarkably upregulated both in the spinal cord of SCI mice and LPS-induced microglia cells. ERCC6 deficiency alleviated neuronal damage and apoptosis. Macrophage infiltration and inflammatory response were suppressed by si-ERCC6 treatment. Moreover, ERCC6 blockage ameliorated astrocyte and microglia activation and cell senescence in the damaged spinal cord. Excessive oxidative stress was significantly decreased by ERCC6 knockdown in SCI.

Conclusion: Collectively, ERCC6 exerts crucial functions in mediating physiological processes (apoptosis, inflammation, senescence, and oxidative stress), implying that ERCC6 might act as a prospective therapeutic target against SCI.

Injectable recombinant block polymer gel for sustained delivery of therapeutic protein in post traumatic osteoarthritis

Protein-based biomaterials offer several advantages over synthetic materials, owing to their unique stimuli-responsive properties, biocompatibility and modular nature. Here, we demonstrate that E5C, a recombinant protein block polymer, consisting of five repeats of elastin like polypeptide (E) and a coiled-coil domain of cartilage oligomeric matrix protein (C), is capable of forming a porous networked gel at physiological temperature, making it an excellent candidate for injectable biomaterials. Combination of E5C with Atsttrin, a chondroprotective engineered derivative of anti-inflammatory growth factor progranulin, provides a unique biochemical and biomechanical environment to protect against post-traumatic osteoarthritis (PTOA) onset and progression. E5C gel was demonstrated to provide prolonged release of Atsttrin and inhibit chondrocyte catabolism while facilitating anabolic signaling in vitro. We also provide in vivo evidence that prophylactic and therapeutic application of Atsttrin-loaded E5C gels protected against PTOA onset and progression in a rabbit anterior cruciate ligament transection model. Collectively, we have developed a unique protein-based gel capable of minimally invasive, sustained delivery of prospective therapeutics, particularly the progranulin-derivative Atsttrin, for therapeutic application in OA.

Analysis of the Biomarkers for Neurodegenerative Diseases in Aged Progranulin Deficient Mice

Neurodegenerative diseases are debilitating impairments that affect millions of people worldwide and are characterized by progressive degeneration of structure and function of the central or peripheral nervous system. Effective biomarkers for neurodegenerative diseases can be used to improve the diagnostic workup in the clinic as well as facilitate the development of effective disease-modifying therapies. Progranulin (PGRN) has been reported to be involved in various neurodegenerative disorders. Hence, in the current study we systematically compared the inflammation and accumulation of typical neurodegenerative disease markers in the brain tissue between PGRN knockout (PGRN KO) and wildtype (WT) mice. We found that PGRN deficiency led to significant neuron loss as well as activation of microglia and astrocytes in aged mice. Several characteristic neurodegenerative markers, including α-synuclein, TAR DNA-binding protein 43 (TDP-43), Tau, and β-amyloid, were all accumulated in the brain of PGRN-deficient mice as compared to WT mice. Moreover, higher aggregation of lipofuscin was observed in the brain tissue of PGRN-deficient mice compared with WT mice. In addition, the autophagy was also defective in the brain of PGRN-deficient mice, indicated by the abnormal expression level of autophagy marker LC3-II. Collectively, comprehensive assays support the idea that PGRN plays an important role during the development of neurodegenerative disease, indicating that PGRN might be a useful biomarker for neurodegenerative diseases in clinical settings.

Gold nanoclusters conjugated berberine reduce inflammation and alleviate neuronal apoptosis by mediating M2 polarization for spinal cord injury repair

Spinal cord injury (SCI) leads to nerve cell apoptosis and loss of motor function. Herein, excessive activation of the M1 phenotype macrophages/microglia is found to be the main reason for the poor prognosis of SCI, but the selective activation phenotype (M2) macrophages/microglia facilitates the recovery of SCI. Thereafter, we used gold nanoclusters loaded berberine (BRB-AuNCs) to reduce inflammation by inhibiting the activation of M1 phenotype macrophages/microglia, which simultaneously inhibited neuronal apoptosis after SCI. In vitro and in vivo experiments showed that BRB-AuNCs reduced M1 protein marker CD86, increased M2 protein marker CD206, reduced inflammation and apoptotic cytokines (IL-1β, IL-6, TNF-α, Cleaved Caspase-3 and Bax). These results indicate that BRB-AuNCs have excellent anti-inflammatory and anti-apoptotic effects by inducing the polarization of macrophages/microglia from M1 phenotype to M2 phenotype. Thereafter, the motor functions of SCI rats were significantly improved after treatment with BRB-AuNCs. This work not only provides a new way for the treatment of SCI but also broadens BRB utilization strategies.

Functional hydrogels as therapeutic tools for spinal cord injury: New perspectives on immunopharmacological interventions

Spinal cord injury (SCI) is a complex medical and psychological challenge for which there is no curative therapy currently available. Despite major progress in pharmacological and surgical approaches, clinical trials for SCI patients have been uniformly disappointing thus far as there are many practical and biological issues yet to be resolved. Neuroinflammation is a critical event of the secondary injury phase after SCI, and recent research strategies have focused on modulating the immune response after injury to provide a more favorable recovery environment. Biomaterials can serve this purpose by providing physical and trophic support to the injured spinal cord after SCI. Of all potential biomaterials, functional hydrogels are emerging as a key component in novel treatment strategies for SCI, including controlled and localized delivery of immunomodulatory therapies to drive polarization of immune cells towards a pro-regenerative phenotype. Here, we extensively review recent developments in the use of functional hydrogels as immunomodulatory therapies for SCI. We briefly describe physicochemical properties of hydrogels and demonstrate how advanced fabrication methods lead to the required heterogeneity and hierarchical arrangements that increasingly mimic complex spinal cord tissue. We then summarize potential SCI therapeutic modalities including: (i) hydrogels alone; (ii) hydrogels as cellular or (iii) bioactive molecule delivery vehicles, and; (iv) combinatorial approaches. By linking the structural properties of hydrogels to their functions in treatment with particular focus on immunopharmacological stimuli, this may accelerate further development of functional hydrogels for SCI, and indeed next-generation central nervous system regenerative therapies.

Cross-Sectional and Longitudinal Associations Between Plasma Neurodegenerative Biomarkers and Physical Performance Among Community-Dwelling Older Adults

BACKGROUND

Plasma amyloid-beta (Aβ), neurofilament light chain (NfL), and progranulin (PGRN) have been related to multiple neurodegenerative conditions that might affect physical performance. The aim of this study was to explore the relationship between these plasma neurodegenerative markers and physical performance among community-dwelling older adults.

METHODS

Five hundred and seven older adults (aged 76 ± 5 years) previously recruited in the Multidomain Alzheimer's Preventive Trial, and had received blood and physical performance tests, were included in this study. Plasma Aβ (Aβ 42/Aβ 40 ratio), NfL, and PGRN levels were measured. Physical performance was assessed by handgrip strength and the Short Physical Performance Battery (combining gait speed, chair stands, and balance tests). Physical performance measured at the same time point and after the blood tests were used. Mixed-effect linear models were performed with age, sex, allocation to Multidomain Alzheimer's Preventive Trial group, body mass index, and Mini-Mental State Examination score as covariates.

RESULTS

The mean values of Aβ 42/Aβ 40 ratio, NfL, and PGRN were 0.11, 84.06 pg/mL, and 45.43 ng/mL, respectively. At the cross-sectional level, higher plasma NfL was associated with a lower Short Physical Performance Battery score (β = -0.004, 95% CI [-0.007, -0.001]). At the longitudinal level, higher PGRN levels were associated with decreasing handgrip strength over time (β = -0.02, 95% CI [-0.04, -0.007]). All the other associations were statistically nonsignificant.

CONCLUSION

Our findings suggest the possibility of using plasma NfL and PGRN as markers of physical performance in older adults.

Small extracellular vesicles encapsulating CCL2 from activated astrocytes induce microglial activation and neuronal apoptosis after traumatic spinal cord injury

Background

Spinal cord injury (SCI) is a severe traumatic disease which causes high disability and mortality rates. The molecular pathological features after spinal cord injury mainly involve the inflammatory response, microglial and neuronal apoptosis, abnormal proliferation of astrocytes, and the formation of glial scars. However, the microenvironmental changes after spinal cord injury are complex, and the interactions between glial cells and nerve cells remain unclear. Small extracellular vesicles (sEVs) may play a key role in cell communication by transporting RNA, proteins, and bioactive lipids between cells. Few studies have examined the intercellular communication of astrocytes through sEVs after SCI. The inflammatory signal released from astrocytes is known to initiate microglial activation, but its effects on neurons after SCI remain to be further clarified.

Methods

Electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blotting were applied to characterize sEVs. We examined microglial activation and neuronal apoptosis mediated by astrocyte activation in an experimental model of acute spinal cord injury and in cell culture in vitro.

Results

Our results indicated that astrocytes activated after spinal cord injury release CCL2, act on microglia and neuronal cells through the sEV pathway, and promote neuronal apoptosis and microglial activation after binding the CCR2. Subsequently, the activated microglia release IL-1β, which acts on neuronal cells, thereby further aggravating their apoptosis.

Conclusion

This study elucidates that astrocytes interact with microglia and neurons through the sEV pathway after SCI, enriching the mechanism of CCL2 in neuroinflammation and spinal neurodegeneration, and providing a new theoretical basis of CCL2 as a therapeutic target for SCI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02268-y.

Effect of electroacupuncture on inhibition of inflammatory response and oxidative stress through activating ApoE and Nrf2 in a mouse model of spinal cord injury

INTRODUCTION

Electroacupuncture protects neurons and myelinated axons after spinal cord injury by mitigating the inflammatory response and oxidative stress, but how it exerts these effects is unclear.

METHODS AND RESULTS

Spinal cord injury was induced in C57BL/6 wild-type and apolipoprotein E (ApoE) knockout (ApoE^-/- ) mice, followed by electroacupuncture or ApoE mimetic peptide COG112 treatment. Mice with spinal cord injury suffered loss of myelinated axons and hindlimb motor function through the detections of Basso mouse scale, histology, and transmission electron microscopy; electroacupuncture partially reversed these effects in wild-type mice but not in ApoE^-/- mice. Combining exogenous ApoE administration with electroacupuncture significantly mitigated the effects of spinal cord injury in both mouse strains, and these effects were associated with up-regulation of anti-inflammatory cytokines and down-regulation of pro-inflammatory cytokines which were detected by quantitative reverse transcription-polymerase chain reaction. Combination treatment also reduced oxidative stress by up-regulating ApoE and Nrf2/HO-1 signaling pathway through the detections of immunofluorescence and western blot analysis.

CONCLUSIONS

These results suggest that electroacupuncture protects neurons and myelinated axons following spinal cord injury through an ApoE-dependent mechanism.

Resveratrol Can Attenuate Astrocyte Activation to Treat Spinal Cord Injury by Inhibiting Inflammatory Responses

Several preclinical and clinical studies have attempted to elucidate the pathophysiological mechanism associated with spinal cord injury. However, investigations have been unable to define the precise related mechanisms, and this has led to the lack of effective therapeutic agents for the condition. Neuroinflammation is one of the predominant processes that hinder spinal cord injury recovery. Resveratrol is a compound that has several biological features, such as antioxidation, antibacterial, and antiinflammation. Herein, we reviewed preclinical and clinical studies to delineate the role of toll-like receptors, nod-like receptors, and astrocytes in neuroinflammation. In particular, the alteration of astrocytes in SCI causes glial scar formation that impedes spinal cord injury recovery. Therefore, to improve injury recovery would be to prevent the occurrence of this process. Resveratrol is safe and effective in the significant modulation of neuroinflammatory factors, particularly those mediated by astrocytes. Thus, its potential ability to enhance the injury recovery process and ameliorate spinal cord injury.

Abnormal spatiotemporal expression pattern of progranulin and neurodevelopment impairment in VPA-induced ASD rat model

Some environmental risk factors have been proven to contribute to the etiology of autism spectrum disorder (ASD). Exposure to the antiepileptic drug valproic acid (VPA) during pregnancy significantly increases the risk of ASD in humans, and consequently is utilized as a validated animal model of ASD in rodents; however, the precise molecular and cellular mechanisms remain ill-defined. In the present study, we investigated the effect of prenatal VPA exposure on the spatiotemporal dynamics of Progranulin (PGRN) expression, neuronal apoptosis, synapse density, and AKT/GSK-3β pathway activation in the brains of VPA-exposed offspring. Results from behavioral tests were consistent with prior studies showing impaired sociability, restricted interests and increased repetitive behaviors in VPA rats at postnatal days 28-32. Our data also indicated that VPA exposure resulted in abnormal dynamics of PGRN expression in different brain regions at the different development stages. The temporal and spatial patterns of PGRN expression were consistent with the spatiotemporal regularity of abnormalities, which observed in apoptosis-related protein levels, neuron numbers, dendritic spine density, synapse-related protein levels, and AKT/GSK-3β phosphorylation in VPA rats. It suggests that prenatal VPA exposure may affect the spatiotemporal regularity of neuronal apoptosis and synaptic development/regression via interfering with the spatiotemporal process of PGRN expression and downstream AKT/GSK-3β pathway activation. This may be a potential mechanism of the abnormal neuroanatomical changes and ASD-like behaviors in VPA-induced ASD.

Single intracerebroventricular progranulin injection adversely affects the blood-brain barrier in experimental traumatic brain injury

Progranulin (PGRN) is a neurotrophic and anti-inflammatory factor with protective effects in animal models of ischemic stroke, subarachnoid hemorrhage, and traumatic brain injury (TBI). Administration of recombinant (r) PGRN prevents exaggerated brain pathology after TBI in Grn-deficient mice, suggesting that local injection of recombinant progranulin (rPGRN) provides therapeutic benefit in the acute phase of TBI. To test this hypothesis, we subjected adult male C57Bl/6N mice to the controlled cortical impact model of TBI, administered a single dose of rPGRN intracerebroventricularly (ICV) shortly before the injury, and examined behavioral and biological effects up to 5 days post injury (dpi). The anti-inflammatory bioactivity of rPGRN was confirmed by its capability to inhibit the inflammation-induced hypertrophy of murine primary microglia and astrocytes in vitro. In C57Bl/6N mice, however, ICV administration of rPGRN failed to attenuate behavioral deficits over the 5-day observation period. (Immuno)histological gene and protein expression analyses at 5 dpi did not reveal a therapeutic benefit in terms of brain injury size, brain inflammation, glia activation, cell numbers in neurogenic niches, and neuronal damage. Instead, we observed a failure of TBI-induced mRNA upregulation of the tight junction protein occludin and increased extravasation of serum immunoglobulin G into the brain parenchyma at 5 dpi. In conclusion, single ICV administration of rPGRN had not the expected protective effects in the acute phase of murine TBI, but appeared to cause an aggravation of blood-brain barrier disruption. The data raise questions about putative PGRN-boosting approaches in other types of brain injuries and disease.

Progranulin promotes functional recovery and neurogenesis in the subventricular zone of adult mice after cerebral ischemia

Progranulin (PGRN), a secreted glycosylated protein, has been reported to attenuate ischemia-induced cerebral injury through anti-inflammation, attenuation of blood-brain barrier disruption and neuroprotection. However, the effect of PGRN on neurogenesis in the subventricular zone (SVZ) after cerebral ischemia remains unclear. In this study, adult C57BL/6 mice were subjected to permanent middle cerebral artery occlusion (pMCAO), and different doses of recombinant mouse PGRN (r-PGRN, 0.3 ng, 1 ng, 5 ng) were intracerebroventricularly administered 30 min after pMCAO. Results showed that 1 ng r-PGRN markedly reduced infarct volume and rescued functional deficits 24 h after pMCAO. Meanwhile, 1 ng r-PGRN increased SVZ cell proliferation, as shown by a high number of bromodeoxyuridine-positive (BrdU+) cells and Ki-67+ cells in the ischemic ipsilateral SVZ 7 d after pMCAO. Additionally, PGRN increased the percentage of BrdU+/Doublecortin (DCX)+ cells in the ipsilateral SVZ 14 d after pMCAO and increased the percentage of new neurons (BrdU+/NeuN+ cells) in the peri-infarct striatum 28 d after pMCAO, suggesting that PGRN promotes neuronal differentiation. PGRN also upregulated phosphorylation of ERK1/2 and Akt in the ipsilateral SVZ 3 d after pMCAO. Our data indicate that PGRN treatment promotes acute functional recovery; most importantly, it also stimulates neurogenesis in the SVZ, which could be beneficial for long-term recovery after cerebral ischemia. The increase in neurogenesis could be associated with activation of the MAPK/ERK and PI3K/Akt pathways. These results suggest a potential new strategy utilizing PGRN in ischemic stroke therapy.

Programmed cell death in spinal cord injury pathogenesis and therapy

Spinal cord injury (SCI) always leads to functional deterioration due to a series of processes including cell death. In recent years, programmed cell death (PCD) is considered to be a critical process after SCI, and various forms of PCD were discovered in recent years, including apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis and paraptosis. Unlike necrosis, PCD is known as an active cell death mediated by a cascade of gene expression events, and it is crucial for elimination unnecessary and damaged cells, as well as a defence mechanism. Therefore, it would be meaningful to characterize the roles of PCD to not only enhance our understanding of the pathophysiological processes, but also improve functional recovery after SCI. This review will summarize and explore the most recent advances on how apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis and paraptosis are involved in SCI. This review can help us to understand the various functions of PCD in the pathological processes of SCI, and contribute to our novel understanding of SCI of unknown aetiology in the near future.

Human progranulin-expressing mice as a novel tool for the development of progranulin-modulating therapeutics

The granulin protein (also known as, and hereafter referred to as, progranulin) is a secreted glycoprotein that contributes to overall brain health. Heterozygous loss-of-function mutations in the gene encoding the progranulin protein (Granulin Precursor, GRN) are a common cause of familial frontotemporal dementia (FTD). Gene therapy approaches that aim to increase progranulin expression from a single wild-type allele, an area of active investigation for the potential treatment of GRN-dependent FTD, will benefit from the availability of a mouse model that expresses a genomic copy of the human GRN gene. Here we report the development and characterization of a novel mouse model that expresses the entire human GRN gene in its native genomic context as a single copy inserted into a defined locus (Hprt) in the mouse genome. We show that human and mouse progranulin are expressed in a similar tissue-specific pattern, suggesting that the two genes are regulated by similar mechanisms. Human progranulin rescues a phenotype characteristic of progranulin-null mice, the exaggerated and early deposition of the aging pigment lipofuscin in the brain, indicating that the two proteins are functionally similar. Longitudinal behavioural and neuropathological analyses revealed no significant differences between wild-type and human progranulin-overexpressing mice up to 18 months of age, providing evidence that long-term increase of progranulin levels is well tolerated in mice. Finally, we demonstrate that human progranulin expression can be increased in the brain using an antisense oligonucleotide that inhibits a known GRN-regulating micro-RNA, demonstrating that the transgene is responsive to potential gene therapy drugs. Human progranulin-expressing mice represent a novel and valuable tool to expedite the development of progranulin-modulating therapeutics.

The protective mechanism of action of plantamajoside on a rat model of acute spinal cord injury

Acute spinal cord injury (ASCI) is a severe traumatic disease of the central nervous system, characterized by a high incidence and high morbidity, for which there are no effective drug therapies in the clinic. A rat model of ASCI was established to study the effects of plantamajoside (PMS) treatment on the expression of apoptotic factors, including caspase-3, caspase-9, poly (ADP-ribose) polymerase (PARP), Bax and Bcl-2. The Allen's weight hit rat ASCI model was used for the present study, and the rats were treated with various concentrations of PMS. The behavior of rats was assessed using the Basso-Beattle-Bresnahan locomotor rating scale (BBB), the histopathologic changes of spinal cord tissue were observed by hematoxylin and eosin staining, the survival of neurons was assessed by TUNEL staining and the expression levels of apoptotic proteins such as caspase-3, caspase-9, PARP, Bcl-2 and Bax was measured using western blot assays and RT-qPCR. It was observed that PMS could reverse the decrease in the BBB score after ASCI, improve the morphological characteristics of the spinal cord, reduce the degree apoptosis and affect the expression of caspase-3, caspase-9, PARP, Bax and Bcl-2 in a concentration dependent manner. In conclusion, PMS protected ASCI rats by inhibiting apoptosis; therefore PMS may be a potential candidate for ASCI therapy.