Sox9 knockout mice have improved recovery following stroke

Corticospinal tract: a new hope for the treatment of post-stroke spasticity

Stroke is the third leading cause of death and disability worldwide. Post-stroke spasticity (PSS) is the most common complication of stroke but represents only one of the many manifestations of upper motor neuron syndrome. As an upper motor neuron, the corticospinal tract (CST) is the only direct descending motor pathway that innervates the spinal motor neurons and is closely related to the recovery of limb function in patients with PSS. Therefore, promoting axonal remodeling in the CST may help identify new therapeutic strategies for PSS. In this review, we outline the pathological mechanisms of PSS, specifically their relationship with CST, and therapeutic strategies for axonal regeneration of the CST after stroke. We found it to be closely associated with astroglial scarring produced by astrocyte activation and its secretion of neurotrophic factors, mainly after the onset of cerebral ischemia. We hope that this review offers insight into the relationship between CST and PSS and provides a basis for further studies.

Peptide-mediated targeted delivery of SOX9 nanoparticles into astrocytes ameliorates ischemic brain injury

Astrocytes are highly activated following brain injuries, and their activation influences neuronal survival. Additionally, SOX9 expression is known to increase in reactive astrocytes. However, the role of SOX9 in activated astrocytes following ischemic brain damage has not been clearly elucidated yet. Therefore, in the present study, we investigated the role of SOX9 in reactive astrocytes using a poly-lactic-co-glycolic acid (PLGA) nanoparticle plasmid delivery system in a photothrombotic stroke animal model. We designed PLGA nanoparticles to exclusively enhance SOX9 gene expression in glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes. Our observations indicate that PLGA nanoparticles encapsulated with GFAP:SOX9:tdTOM reduce ischemia-induced neurological deficits and infarct volume through the prostaglandin D2 pathway. Thus, the astrocyte-targeting PLGA nanoparticle plasmid delivery system provides a potential opportunity for stroke treatment. Since the only effective treatment currently available is reinstating the blood supply, cell-specific gene therapy using PLGA nanoparticles will open a new therapeutic paradigm for brain injury patients in the future.

Astrocyte Regulation of Neuronal Function and Survival in Stroke Pathophysiology

The interactions between astrocytes and neurons in the context of stroke play crucial roles in the disease's progression and eventual outcomes. After a stroke, astrocytes undergo significant changes in their morphology, molecular profile, and function, together termed reactive astrogliosis. Many of these changes modulate how astrocytes relate to neurons, inducing mechanisms both beneficial and detrimental to stroke recovery. For example, excessive glutamate release and astrocytic malfunction contribute to excitotoxicity in stroke, eventually causing neuronal death. Astrocytes also provide essential metabolic support and neurotrophic signals to neurons after stroke, ensuring homeostatic stability and promoting neuronal survival. Furthermore, several astrocyte-secreted molecules regulate synaptic plasticity in response to stroke, allowing for the rewiring of neural circuits to compensate for damaged areas. In this chapter, we highlight the current understanding of the interactions between astrocytes and neurons in response to stroke, explaining the varied mechanisms contributing to injury progression and the potential implications for future therapeutic interventions.

Astrocytes in stroke-induced neurodegeneration: a timeline

Stroke is a condition characterized by sudden deprivation of blood flow to a brain region and defined by different post-injury phases, which involve various molecular and cellular cascades. At an early stage during the acute phase, fast initial cell death occurs, followed by inflammation and scarring. This is followed by a sub-acute or recovery phase when endogenous plasticity mechanisms may promote spontaneous recovery, depending on various factors that are yet to be completely understood. At later time points, stroke leads to greater neurodegeneration compared to healthy controls in both clinical and preclinical studies, this is evident during the chronic phase when recovery slows down and neurodegenerative signatures appear. Astrocytes have been studied in the context of ischemic stroke due to their role in glutamate re-uptake, as components of the neurovascular unit, as building blocks of the glial scar, and synaptic plasticity regulators. All these roles render astrocytes interesting, yet understudied players in the context of stroke-induced neurodegeneration. With this review, we provide a summary of previous research, highlight astrocytes as potential therapeutic targets, and formulate questions about the role of astrocytes in the mechanisms during the acute, sub-acute, and chronic post-stroke phases that may lead to neurorestoration or neurodegeneration.

Emerging Role of MicroRNA-30c in Neurological Disorders

MicroRNAs (miRNAs or miRs) are a class of small non-coding RNAs that negatively regulate the expression of target genes by interacting with 3' untranslated regions of target mRNAs to induce mRNA degradation and translational repression. The miR-30 family members are involved in the development of many tissues and organs and participate in the pathogenesis of human diseases. As a key member of the miR-30 family, miR-30c has been implicated in neurological disorders such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and stroke. Mechanistically, miR-30c may act as a multi-functional regulator of different pathogenic processes such as autophagy, apoptosis, endoplasmic reticulum stress, inflammation, oxidative stress, thrombosis, and neurovascular function, thereby contributing to different disease states. Here, we review and discuss the biogenesis, gene regulation, and the role and mechanisms of action of miR-30c in several neurological disorders and therapeutic potential in clinics.

Sam50 exerts neuroprotection by maintaining the mitochondrial structure during experimental cerebral ischemia/reperfusion injury in rats

AIM

To investigate the role of Sam50, a barrel protein on the surface of the mitochondrial outer membrane, in cerebral ischemia-reperfusion (I/R) injury and its underlying mechanisms.

METHODS

A middle cerebral artery occlusion/reperfusion (MCAO/R) model in adult male Sprague-Dawley rats was established in vivo, and cultured neurons were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate I/R injury in vitro. Lentiviral vector encoding Sam50 or Sam50 shRNA was constructed and administered to rats by intracerebroventricular injection to overexpress and knockdown Sam50, respectively.

RESULTS

First, after MCAO/R induction, the mitochondrial structure was damaged, and Sam50 protein levels were increased responsively both in vivo and in vitro. Then, it was found that Sam50 overexpression could reduce infarction size, inhibit neuronal cell death, improve neurobehavioral disability, protect mitochondrial structure integrity, and ameliorate mitochondrial dysfunction, which was induced by I/R injury both in vivo and in vitro. However, Sam50 downregulation showed the opposite results and aggravated I/R injury by inducing neuronal cell death, neurobehavioral disability, and mitochondrial dysfunction. Moreover, we found that the interaction between Sam50 and Mic19 was broken off after OGD/R, showing that the Sam50-Mic19-Mic60 axis was breakage in neurons, which would be a reason for mitochondrial structure and function abnormalities induced by I/R injury.

CONCLUSION

Sam50 played a vital role in the protection of neurons and mitochondria in cerebral I/R injury, which could be a novel target for mitochondrial protection and ameliorating I/R injury.

Single-Cell Transcriptomic Analysis Demonstrates the Regulation of Peach Polysaccharides on Circadian Rhythm Disturbance

SCOPE

Plant polysaccharides are thought to have a prebiotic effect, promoting the growth of probiotics, which may regulate circadian rhythms. This study evaluates the regulation of peach polysaccharides (PPS) on circadian rhythm disturbance through intestinal microbiota by a mouse model.

METHODS AND RESULTS

PPS is administered to mice with circadian rhythm disturbance for 4 weeks. The study finds that PPS ameliorated the structural disorder of intestinal microbiota induced by continuous darkness, decreasing the ratio of Firmicutes/Bacteroidetes (F/B), thereby regulating furfural degradation, penicillin and cephalosporin biosynthesis, and antibiotic biosynthesis. Single-cell transcriptomics is used to determine the type of hypothalamus cells and the expression of clock genes in mice, showing that the number of astrocytes and oligoendrocytes cells in the hypothalamus of the transplanted mice is up-regulated, and the expression of neuroprotective genes such as Sox9 and Mobp increased. In addition, clock genes such as Cry2 and Per3 show significant callback.

CONCLUSION

This study shows that PPS can ameliorate the imbalance of intestinal microbiota and cell dysfunction caused by circadian rhythm disorder, suggesting that PPS is a feasible strategy for the prevention and treatment of circadian rhythm disorder and related cognitive impairment.

Flurbiprofen axetil protects against cerebral ischemia/reperfusion injury via regulating miR-30c-5p and SOX9

The modulatory mechanism of flurbiprofen axetil (FPA) by which it relieves cerebral ischemia/reperfusion (I/R) injury (CIRI) is still obscure. In the present work, adult male Sprague-Dawley (SD) rats were pre-treated with FPA before the construction of a rat model of CIRI. Longa's scoring method and dry-wet method were employed to examine the neurological function and brain water content of the rats. MiR-30c-5p, SOX9, AQP4, SOX9, NF-κB, and p-NF-κB expression levels in the brain tissues of the rats were examined by qRT-PCR or Western blot. ELISA was executed to evaluate the IL-10, IL-6, and TNF-α levels in the serum of rat. SOD and MDA levels in rat brain homogenates were also examined to indicate the oxidative stress. Hematoxylin-eosin (HE) staining was used to examine the pathological changes of the brain tissues. Dual-luciferase reporter gene experiment was implemented to validate the binding relationship between miR-30c-5p and SOX9. In the present work, compared with the rats with CIRI, FPA pre-treatment attenuated neurological injury, cerebral edema, oxidative stress, inflammatory response, and cerebral pathological changes in the rat model with CIRI. FPA up-modulated miR-30c-5p expression. SOX9 was a downstream target of miR-30c-5p. In conclusion, FPA ameliorates CIRI through up-modulating miR-30c-5p expression and reducing SOX9 expression.

Reconstruction of the corticorubral tract in the human brain using diffusion tensor tractography

The corticorubral tract (CRT) facilitates fine motor coordination. However, no diffusion tensor tractography (DTT) study has been conducted although a few studies have reported on the cortical connection of the red nucleus. In this study, we investigated the DTT reconstruction method and DTT characteristics of the CRT in normal subjects. Thirty-six right-handed normal subjects were recruited. Diffusion tensor images were scanned using a 1.5 T MRI scanner. For analysis of the CRT, the seed region of interest (ROI) was placed on the red nucleus of the midbrain, and the target ROI was placed on the primary sensorimotor cortex. Values of fractional anisotropy (FA), mean diffusivity (MD), and tract volume (TV) of the CRT were obtained for both hemispheres. Among the 72 cerebral hemispheres of the 36 normal subjects, the neural tract between the red nucleus and the primary sensorimotor cortex was reconstructed in 66 hemispheres (92%). The reconstructed CRT, which originated from the primary sensorimotor cortex, descended through the posterior portion of the centrum semiovale, the corona radiata and posterior limb of the internal capsule, and terminated at the red nucleus. Analysis of the FA, MD, and TV values revealed no significant differences between the right and left hemispheres (p > 0.05). We describe the method of DTT reconstruction and the imaging parameters of the CRT in the brain of normal subjects. We believe that the DTT method and associated parameter results for the CRT in normal subjects will be useful in future neuroscience studies.

SOX9 Knockdown-Mediated FOXO3 Downregulation Confers Neuroprotection Against Ischemic Brain Injury

Background

Evidence exists uncovering that SRY-box transcription factor 9 (SOX9) plays a role in ischemic brain injury (IBI). Thus, the current study was conducted to elucidate the specific role of SOX9 and the mechanism by which SOX9 influenced IBI.

Methods

The IBI-associated regulatory factors were searched by bioinformatics analysis. The rat model of IBI was generated using middle cerebral artery occlusion (MCAO) treatment. Neuronal cells were exposed to oxygen-glucose deprivation (OGD). The expressions of SOX9, forkhead box O3 (FOXO3), transcription of Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2), and IκB kinase α (IKKα) in OGD-treated neuronal cells were characterized using reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay. The interaction among CITED2, IKKα, and FOXO3 was identified by chromatin immunoprecipitation (ChIP) and dual luciferase reporter gene assays. Gain- and loss-of-function experiments were performed to verify the relationship among SOX9, FOXO3, CITED2, and IKKα and to investigate their functional effects on apoptosis and the inflammatory response of OGD-treated neuronal cells as well as neurological deficit and infarct area of the rat brain.

Results

SOX9, FOXO3, CITED2, and IKKα were highly expressed in OGD-treated neuronal cells. Silencing of SOX9 inhibited OGD-induced neuronal apoptosis and inflammatory response and reduced the neurological deficit and infarct area of the brain in the rats, which were caused by MCAO but were reversed by overexpressing FOXO3, CITED2, or IKKα.

Conclusion

Taken together, our study suggested that upregulation of SOX9 promoted IBI though upregulation of the FOXO3/CITED2/IKKα axis, highlighting a basic therapeutic consideration for IBI treatment.

H3K27 demethylase KDM6B aggravates ischemic brain injury through demethylation of IRF4 and Notch2-dependent SOX9 activation

Lysine demethylase 6B (KDM6B) is a histone H3 lysine 27 (H3K27) demethylase that serves as a key mediator of gene transcription. Although KDM6B has been reported to modulate neuroinflammation after ischemic stroke, its role in ischemic brain injury is yet to be well elucidated. Therefore, this study aimed to thoroughly demonstrate the molecular mechanism underlying the effect of KDM6B on neurological function and astrocyte response in post-ischemic brain injury. Middle cerebral artery occlusion/reperfusion (MCAO) mouse models were constructed, while the oxygen-glucose deprivation/reperfusion (OGD/R) model was developed in astrocytes to mimic injury conditions. KDM6B was upregulated post-MCAO in mice and in astrocytes following the induction of OGD/R. Silencing of KDM6B resulted in suppressed neurological deficit, reduced cerebral infarction volume, attenuated neuronal cell apoptosis, and disrupted inflammation. Dual-luciferase reporter gene and chromatin immunoprecipitation-quantitative polymerase chain reaction assays revealed that KDM6B inhibited H3K27 trimethylation in the interferon regulatory factor 4 (IRF4) promoter region, resulting in the upregulation of IRF4 expression, which in turn bound to the Notch2 promoter region to induce its downstream factor SRY-related high-mobility group box 9 (SOX9). SOX9 knockdown reversed the effects of KDM6B overexpression on ischemia-triggered brain damage. Based on these findings, we concluded that KDM6B-mediated demethylation of IRF4 contributes to aggravation of ischemic brain injury through SOX9 activation.

Virtual Screening of the Multi-pathway and Multi-gene Regulatory Molecular Mechanism of Dachengqi Decoction in the Treatment of Stroke Based on Network Pharmacology

BACKGROUND

Stroke is ranked second among diseases that cause mortality worldwide. Owing to its complicated pathogenesis, no satisfactory treatment strategies for stroke are available. Dachengqi decoction (DCQD), a traditional Chinese herbal medicine, has been widely used in China for a long time, as it has a good effect on stroke. However, the molecular mechanism underlying this effect of DCQD is unclear.

OBJECTIVE

In the present study, we aimed to reveal and explore the multi-pathway and multi-gene regulatory molecular mechanism of Dachengqi decoction in the treatment of stroke.

METHODS

In this study, a network pharmacology method, in combination with oral bioavailability prediction and drug-likeness evaluation, was employed to predict the active ingredients of DCQD. The target genes of the active components and the traced pathways related to these target genes were predicted. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using clusterProfiler software package on the R platform and ClueGo+CluePedia plug-ins. Finally, the key DCQD targets were verified using the Gene Expression Omnibus (GEO) dataset.

RESULTS AND DISCUSSION

According to the ADME model, 52 active components were screened from 296 active components of DCQD. After prediction and screening, 215 stroke-related targets were obtained and analyzed via GO and KEGG analyses. GO analysis showed that DCQD targets were mainly involved in the regulation of oxidative stress, lipid metabolism, inflammation, and other biological processes. KEGG pathway analysis further revealed pathways involved in stroke, such as arachidonic acid metabolic, HIF-1 signaling pathway, estrogen signaling pathway, MAPK signaling pathway, PI3K-Akt signaling pathway, platelet activation pathway, VEGF signaling pathway, and cAMP signaling pathway. Network analysis revealed that DCQD might be involved in the regulation of lipid metabolism, blood pressure, inflammation, angiogenesis, neuroprotection, platelet aggregation, apoptosis, and oxidation in stroke treatment. GEO dataset analysis showed that DCQD's therapeutic effects might be exerted via the bidirectional regulation principle.

CONCLUSION

Based on the methods of network pharmacology and GEO analysis, it was found that, during stroke treatment, DCQD regulates and controls multiple genes and multiple pathways in a synergistic manner, providing a new strategy for stroke treatment.

Curcumin Can Improve Spinal Cord Injury by Inhibiting TGF-β-SOX9 Signaling Pathway

Spinal cord injury (SCI) is a severe nervous system disease with high morbidity and disability rate. Signaling pathways play a key role in the neuronal restorative mechanism following SCI. SRY-related high mobility group (HMG)-box gene 9 (SOX9) affects glial scar formation via Transforming growth factor beta (TGF-β) signaling pathway. Activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is transferred into nucleus to upregulate TGF-β-SOX9. Curcumin exhibits potent anti-inflammatory and anti-oxidant properties. Curcumin can play an important role in SCI recovery by inhibiting the expression of NF-κB and TGF-β-SOX9. Herein, we review the potential mechanism of curcumin-inhibiting SOX9 signaling pathway in SCI treatment. The inhibition of NF-κB and SOX9 signaling pathway by curcumin has the potentiality of serving as neuronal regenerative mechanism following SCI.

CRISPR-mediated SOX9 knockout inhibits GFAP expression in retinal glial (Müller) cells

Müller cells, as the predominant glial element in the sensory retina, play a crucial role in healthy and diseased retina. Overactivation of Müller cells in response to damage is detrimental to the retina tissue. Current research shows that inhibiting glial fibrillary acidic protein (GFAP), a sensitive indicator of Müller cell activation, attenuated glial reactions and promoted neuroprotection. Recent evidence suggests that the transcript factor SOX9 (sex-determining region Y box 9), part of the SOX family, regulates GFAP expression of astrocytes in the central nervous system. However, in retina Müller cells, it is still unknown whether GFAP can be downregulated by reduced SOX9 function. The present results show that clustered regularly interspaced short palindromic repeats/Cas9-mediated SOX9 knockout not only inhibited GFAP expression in rat Müller cells but also attenuated cell migration ability. These results suggest that inhibition of SOX9 activity may be a novel therapeutic strategy for reduction of glial cell activity.

Gasdermin D serves as a key executioner of pyroptosis in experimental cerebral ischemia and reperfusion model both in vivo and in vitro

Even though ischemic stroke is among the leading causes of death worldwide, the pathogenic mechanisms underlying ischemia reperfusion (I/R) brain injury remain unclear. Gasdermin D (GSDMD), as an important factor of pyroptotic death execution downstream of caspase-11 (noncanonical inflammasome) and caspase-1 (canonical inflammasome), may be implicated in I/R injury. The current study aimed to investigate the role and possible underlying mechanisms of GSDMD in pyroptosis during I/R injury. Results indicated that the nucleotide-binding oligomerization domain-like receptors (NLR family) pyrin domain containing 3 (NLRP3) inflammasomes were assembled and activated after middle cerebral artery occlusion/reperfusion (MCAO/R), leading to increased levels of IL-1β and IL-18. Additionally, GSDMD levels were elevated, and its N-terminal fragment (GSDMD-N) was cleaved to induce pyroptosis after MCAO/R, which was partly dependent on caspase-1 activation and its Asp280 amino acid site. Furthermore, it was found that GSDMD-N could bind to membrane lipids and exhibit membrane-disrupting cytotoxicity, depending on its Glu15 and Leu156 amino acid sites. Nevertheless, the C-terminal fragment of gasdermin (GSDMD-C) exhibited an auto-inhibitory effect on GSDMD-N-induced pyroptosis via binding to GSDMD in the cytoplasm. Taken together, this information suggests that GSDMD may participate in caspase-1-mediated pyroptosis during I/R injury both in vivo and in vitro, which could be a potential therapeutic target to reduce brain I/R injury.

Spinal Cord Injury Scarring and Inflammation: Therapies Targeting Glial and Inflammatory Responses

Deficits in neuronal function are a hallmark of spinal cord injury (SCI) and therapeutic efforts are often focused on central nervous system (CNS) axon regeneration. However, secondary injury responses by astrocytes, microglia, pericytes, endothelial cells, Schwann cells, fibroblasts, meningeal cells, and other glia not only potentiate SCI damage but also facilitate endogenous repair. Due to their profound impact on the progression of SCI, glial cells and modification of the glial scar are focuses of SCI therapeutic research. Within and around the glial scar, cells deposit extracellular matrix (ECM) proteins that affect axon growth such as chondroitin sulfate proteoglycans (CSPGs), laminin, collagen, and fibronectin. This dense deposition of material, i.e., the fibrotic scar, is another barrier to endogenous repair and is a target of SCI therapies. Infiltrating neutrophils and monocytes are recruited to the injury site through glial chemokine and cytokine release and subsequent upregulation of chemotactic cellular adhesion molecules and selectins on endothelial cells. These peripheral immune cells, along with endogenous microglia, drive a robust inflammatory response to injury with heterogeneous reparative and pathological properties and are targeted for therapeutic modification. Here, we review the role of glial and inflammatory cells after SCI and the therapeutic strategies that aim to replace, dampen, or alter their activity to modulate SCI scarring and inflammation and improve injury outcomes.