Matrine promotes neural circuit remodeling to regulate motor function in a mouse model of chronic spinal cord injury

Pharmacological intervention for chronic phase of spinal cord injury

Spinal cord injury is an intractable traumatic injury. The most common hurdles faced during spinal cord injury are failure of axonal regrowth and reconnection to target sites. These also tend to be the most challenging issues in spinal cord injury. As spinal cord injury progresses to the chronic phase, lost motor and sensory functions are not recovered. Several reasons may be attributed to the failure of recovery from chronic spinal cord injury. These include factors that inhibit axonal growth such as activated astrocytes, chondroitin sulfate proteoglycan, myelin-associated proteins, inflammatory microglia, and fibroblasts that accumulate at lesion sites. Skeletal muscle atrophy due to denervation is another chronic and detrimental spinal cord injury-specific condition. Although several intervention strategies based on multiple outlooks have been attempted for treating spinal cord injury, few approaches have been successful. To treat chronic spinal cord injury, neural cells or tissue substitutes may need to be supplied in the cavity area to enable possible axonal growth. Additionally, stimulating axonal growth activity by extrinsic factors is extremely important and essential for maintaining the remaining host neurons and transplanted neurons. This review focuses on pharmacotherapeutic approaches using small compounds and proteins to enable axonal growth in chronic spinal cord injury. This review presents some of these candidates that have shown promising outcomes in basic research ( in vivo animal studies) and clinical trials: AA-NgR(310)ecto-Fc (AXER-204), fasudil, phosphatase and tensin homolog protein antagonist peptide 4, chondroitinase ABC, intracellular sigma peptide, (-)-epigallocatechin gallate, matrine, acteoside, pyrvate kinase M2, diosgenin, granulocyte-colony stimulating factor, and fampridine-sustained release. Although the current situation suggests that drug-based therapies to recover function in chronic spinal cord injury are limited, potential candidates have been identified through basic research, and these candidates may be subjects of clinical studies in the future. Moreover, cocktail therapy comprising drugs with varied underlying mechanisms may be effective in treating the refractory status of chronic spinal cord injury.

Mobilizing endogenous neuroprotection: the mechanism of the protective effect of acupuncture on the brain after stroke

Given its high morbidity, disability, and mortality rates, ischemic stroke (IS) is a severe disease posing a substantial public health threat. Although early thrombolytic therapy is effective in IS treatment, the limited time frame for its administration presents a formidable challenge. Upon occurrence, IS triggers an ischemic cascade response, inducing the brain to generate endogenous protective mechanisms against excitotoxicity and inflammation, among other pathological processes. Stroke patients often experience limited recovery stages. As a result, activating their innate self-protective capacity [endogenous brain protection (EBP)] is essential for neurological function recovery. Acupuncture has exhibited clinical efficacy in cerebral ischemic stroke (CIS) treatment by promoting the human body's self-preservation and "Zheng Qi" (a term in traditional Chinese medicine (TCM) describing positive capabilities such as self-immunity, self-recovery, and disease prevention). According to research, acupuncture can modulate astrocyte activity, decrease oxidative stress (OS), and protect neurons by inhibiting excitotoxicity, inflammation, and apoptosis via activating endogenous protective mechanisms within the brain. Furthermore, acupuncture was found to modulate microglia transformation, thereby reducing inflammation and autoimmune responses, as well as promoting blood flow restoration by regulating the vasculature or the blood-brain barrier (BBB). However, the precise mechanism underlying these processes remains unclear. Consequently, this review aims to shed light on the potential acupuncture-induced endogenous neuroprotective mechanisms by critically examining experimental evidence on the preventive and therapeutic effects exerted by acupuncture on CIS. This review offers a theoretical foundation for acupuncture-based stroke treatment.

Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Promote the Recovery of Spinal Cord Injury and Inhibit Ferroptosis by Inactivating IL-17 Pathway

Mesenchymal stem cell (MSC)-derived exosomes are considered as alternative to cell therapy in various diseases. This study aimed to understand the effect of bone marrow MSC-derived exosomes (BMMSC-exos) on spinal cord injury (SCI) and to unveil its regulatory mechanism on ferroptosis. Exosomes were isolated from BMMSCs and the uptake of BMMSCs-exos by PC12 cells was determined using PKH67 staining. The effect of BMMSC-exos on SCI in rats was studied by evaluating pathological changes of spinal cord tissues, inflammatory cytokines, and ferroptosis-related proteins. Transcriptome sequencing was used to discover the differential expressed genes (DEGs) between SCI rats and BMMSC-exos-treated rats followed by functional enrichment analyses. The effect of BMMSC-exos on ferroptosis and interleukin 17 (IL-17) pathway was evaluated in SCI rats and oxygen-glucose deprivation (OGD)-treated PC12 cells. The results showed that particles extracted from BMMSCs were exosomes that could be taken up by PC12 cells. BMMSC-exos treatment ameliorated injuries of spinal cord, suppressed the accumulation of Fe2+, malondialdehyde (MDA), and reactive oxygen species (ROS), with the elevated glutathione (GSH). Also, BMMSC-exos downregulated the expression of acyl-CoA synthetase long chain family member 4 (ACSL4) and upregulated glutathione peroxidase 4 (GPX4) and cysteine/glutamate antiporter xCT. A total of 110 DEGs were discovered and they were mainly enriched in IL-17 signaling pathway. Further in vitro and in vivo experiments showed that BMMSC-exos inactivated IL-17 pathway. BMMSC-exos promote the recovery of SCI and inhibit ferroptosis by inhibiting the IL-17 pathway, which provides BMMSC-exos as an alternative to the management of SCI.

Small molecule regulators of microRNAs identified by high-throughput screen coupled with high-throughput sequencing

MicroRNAs (miRNAs) regulate fundamental biological processes by silencing mRNA targets and are dysregulated in many diseases. Therefore, miRNA replacement or inhibition can be harnessed as potential therapeutics. However, existing strategies for miRNA modulation using oligonucleotides and gene therapies are challenging, especially for neurological diseases, and none have yet gained clinical approval. We explore a different approach by screening a biodiverse library of small molecule compounds for their ability to modulate hundreds of miRNAs in human induced pluripotent stem cell-derived neurons. We demonstrate the utility of the screen by identifying cardiac glycosides as potent inducers of miR-132, a key neuroprotective miRNA downregulated in Alzheimer's disease and other tauopathies. Coordinately, cardiac glycosides downregulate known miR-132 targets, including Tau, and protect rodent and human neurons against various toxic insults. More generally, our dataset of 1370 drug-like compounds and their effects on the miRNome provides a valuable resource for further miRNA-based drug discovery.

Research progress on the pharmacological effects of matrine

Matrine possesses anti-cancer properties, as well as the prevention and treatment of allergic asthma, and protection against cerebral ischemia-reperfusion injury. Its mechanism of action may be (1) regulation of cancer cell invasion, migration, proliferation, and cell cycle to inhibit tumor growth; (2) reduction of oxidized low-density lipoprotein and advanced glycation end products from the source by exerting anti-inflammatory and antioxidant effects; (3) protection of brain damage and cortical neurons by regulating apoptosis; (4) restoration of the intestinal barrier and regulation of the intestinal microbiota. This article aims to explore matrine’s therapeutic potential by summarizing comprehensive information on matrine’s pharmacology, toxicity, and bioavailability.

miR-672-3p Promotes Functional Recovery in Rats with Contusive Spinal Cord Injury by Inhibiting Ferroptosis Suppressor Protein 1

Aberrantly expressed microRNAs (miRNAs) after spinal cord injury (SCI) participate in diverse biological pathways and processes, including apoptosis, inflammation, oxidative stress responses, peroxidation, and ferroptosis. This study was aimed at exploring the mechanisms underlying miRNA-mediated ferroptosis in an SCI rat model. In the present study, a T10 weight-dropping SCI model was established and miRNA profiling was used to detect miRNA expression profiles post-SCI. Basso-Beattie-Bresnahan scores and inclined plane test, hematoxylin and eosin (HE) and Nissl staining, immunohistochemistry and immunofluorescence, western blotting, cell viability, and Annexin V/7-aminoactinomycin D (7-AAD) assays were used to evaluate locomotor activity, histological changes in the injured spinal cords, neuronal ferroptosis, ferroptosis suppressor protein 1 (FSP1) expression, and cell death, respectively. It was observed that many miRNAs were differentially expressed after SCI, and miR-672-3p, which increased significantly, was selected after cross-referencing with predicted target miRNAs. The luciferase reporter assay demonstrated that miR-672-3p downregulated FSP1, a glutathione-independent ferroptosis suppressor, by binding to its 3 ${}^{\prime }$ untranslated region. Oxygen and glucose deprivation- (OGD-) treated PC12 and AGE1.HN cells were treated with miR-672-3p mimics or inhibitors in vitro. The effect of miR-672-3p mimics or inhibitor on OGD-PC12/AGE1.HN ferroptosis was evaluated by flow cytometry, immunohistochemistry, immunofluorescence, and western blotting. The miR-672-3p mimics promoted ferroptosis after SCI, whereas the miR-672-3p inhibitor inhibited this process. Rats with SCI treated with miR-672-3p mimics or inhibitor showed similar results in vivo. Furthermore, the ferroptosis-related changes caused by SCI or miR-672-3p were reversed by overexpression of FSP1 lentivirus in vivo and in vitro. These results indicated that sh-miR-672-3p exerted a neural restoration effect in vivo and in vitro by inhibiting ferroptosis via the FSP1 pathway.

The Advances on Bioactivities, Mechanisms of Action, and Structural Optimizations of Matrine and Its Derivatives

Matrine, a tetracyclo-quinolizidine alkaloid, is isolated from the industrial crop plant Sophora flavescens. Due to a wide range of pharmacological and agricultural properties, the research on the phytochemistry, pharmacology, toxicology and mechanisms of action of matrine and its derivatives has received much attention. On the other hand, to improve their biological activities, the study on structural optimizations and structure-activity relationships of matrine and its derivatives has also attached more and more importance. In this review article, the update advances on bioactivities, mechanisms of action, structural modifications and structure-activity relationships of matrine and its derivatives from 2017 to 2020 are presented. We hope that this review will provide a reference for the development and application of matrine and its derivatives as drugs or pesticides in the future.

Matrine: A review of its pharmacology, pharmacokinetics, toxicity, clinical application and preparation researches

ETHNOPHARMACOLOGICAL RELEVANCE

"Dogel ebs" was known as Sophora flavescens Ait., which has been widely utilized in the clinical practice of traditional Chinese Mongolian herbal medicine for thousands of years. Shen Nong's Materia Medica (Shen Nong Ben Cao Jing in Chinese pinyin) recorded that it is bitter in taste and cold in nature with the effect of clearing heat and eliminating dampness, insecticide, diuresis. Due to its extensive application in the fields of ethnopharmacological utilization, the pharmaceutical researches of Sophora flavescens Ait.s keeps deepening. Modern pharmacological studies have exhibited that matrine, which is rich in this traditional herbal medicine, mediates its main biological properties.

AIMS OF THE REVIEW

This review aimed at summarizing the latest and comprehensive information of matrine on the pharmacology, pharmacokinetics, toxicity, clinical application and preparation researches to explore the therapeutic potential of this natural ingredient. In addition, outlooks and perspective for possible future researches that related are also discussed.

MATERIALS AND METHODS

Related information concerning matrine was gathered from the internet database of Google scholar, Pubmed, ResearchGate, Web of Science and Wiley Online Library with the keywords including "matrine", "pharmacology", "toxicology" and "pharmacokinetics", "clinical application", etc. RESULTS: Based on literatures, matrine has a variety of pharmacological effects, including anti-cancer, anti-inflammatory, anti-microbial, detoxification and so on. Nevertheless, there are still some doubts about it due to the toxicity and questionable bioavailability that does exist.

CONCLUSIONS

Future researches directions probably include elucidate the mechanism of its toxicity and accurately tracing the in vivo behavior of its drug delivery system. Without doubt, integration of toxicity and efficiency and structure modification based on it are also pivotal methods to enhance pharmacological activity and bioavailability.

Multimodal treatment for spinal cord injury: a sword of neuroregeneration upon neuromodulation

Spinal cord injury is linked to the interruption of neural pathways, which results in irreversible neural dysfunction. Neural repair and neuroregeneration are critical goals and issues for rehabilitation in spinal cord injury, which require neural stem cell repair and multimodal neuromodulation techniques involving personalized rehabilitation strategies. Besides the involvement of endogenous stem cells in neurogenesis and neural repair, exogenous neural stem cell transplantation is an emerging effective method for repairing and replacing damaged tissues in central nervous system diseases. However, to ensure that endogenous or exogenous neural stem cells truly participate in neural repair following spinal cord injury, appropriate interventional measures (e.g., neuromodulation) should be adopted. Neuromodulation techniques, such as noninvasive magnetic stimulation and electrical stimulation, have been safely applied in many neuropsychiatric diseases. There is increasing evidence to suggest that neuromagnetic/electrical modulation promotes neuroregeneration and neural repair by affecting signaling in the nervous system; namely, by exciting, inhibiting, or regulating neuronal and neural network activities to improve motor function and motor learning following spinal cord injury. Several studies have indicated that fine motor skill rehabilitation training makes use of residual nerve fibers for collateral growth, encourages the formation of new synaptic connections to promote neural plasticity, and improves motor function recovery in patients with spinal cord injury. With the development of biomaterial technology and biomechanical engineering, several emerging treatments have been developed, such as robots, brain-computer interfaces, and nanomaterials. These treatments have the potential to help millions of patients suffering from motor dysfunction caused by spinal cord injury. However, large-scale clinical trials need to be conducted to validate their efficacy. This review evaluated the efficacy of neural stem cells and magnetic or electrical stimulation combined with rehabilitation training and intelligent therapies for spinal cord injury according to existing evidence, to build up a multimodal treatment strategy of spinal cord injury to enhance nerve repair and regeneration.

PLG Bridge Implantation in Chronic SCI Promotes Axonal Elongation and Myelination

Spinal cord injury (SCI) is a devastating condition that may cause permanent functional loss below the level of injury, including paralysis and loss of bladder, bowel, and sexual function. Patients are rarely treated immediately, and this delay is associated with tissue loss and scar formation that can make regeneration at chronic time points more challenging. Herein, we investigated regeneration using a poly(lactide-co-glycolide) multichannel bridge implanted into a chronic SCI following surgical resection of necrotic tissue. We characterized the dynamic injury response and noted that scar formation decreased at 4 and 8 weeks postinjury (wpi), yet macrophage infiltration increased between 4 and 8 wpi. Subsequently, the scar tissue was resected and bridges were implanted at 4 and 8 wpi. We observed robust axon growth into the bridge and remyelination at 6 months after initial injury. Axon densities were increased for 8 week bridge implantation relative to 4 week bridge implantation, whereas greater myelination, particularly by Schwann cells, was observed with 4 week bridge implantation. The process of bridge implantation did not significantly decrease the postinjury function. Collectively, this chronic model follows the pathophysiology of human SCI, and bridge implantation allows for clear demarcation of the regenerated tissue. These data demonstrate that bridge implantation into chronic SCI supports regeneration and provides a platform to investigate strategies to buttress and expand regeneration of neural tissue at chronic time points.