p5 Peptide-Loaded Human Adipose-Derived Mesenchymal Stem Cells Promote Neurological Recovery After Focal Cerebral Ischemia in a Rat Model

Function of miR-21-5p derived from ADSCs-exos on the neuroinflammation after cerebral ischemia

INTRODUCTION

Cerebral ischemia (CI) induces a profound neuroinflammatory response, but the underlying molecular mechanism remains unclear. Exosomes from adipose-derived stem cells (ADSC-exos) have been found to play a crucial role in cell communication by transferring molecules including microRNAs (miRNAs), which have been shown to modulate the inflammatory response after CI and are viable molecular targets for altering brain function. The current study aimed to explore the contribution of ADSC-exosomal miR-21-5p to the neuroinflammation after CI.

METHODS

The differentially expressed miR-21-5p in CI was screened based on literature search. The target mRNAs of miR-21-5p were predicted using online databases and verified by luciferase reporter assay. Then, BV2 cells were treated with hemin to simulate the inflammatory response after CI, and its animal model was induced using the MCAO method. Ischemia was evaluated in rats using 2, 3, 5-triphenyl tetrazolium chloride (TTC) staining. ADSCs-exos were further isolated and identified by western blot analysis and transmission electron microscope.

RESULTS

MiR-21-5p was significantly down-regulated in CI and alleviated neuropathic damage after CI by the PIK3R1/PI3K/AKT signaling axis. And miR-21-5p derived from ADSCs-exos alleviated neuroinflammation after CI via promoting microglial M2 polarization.

CONCLUSION

We demonstrated that ADSC-exosomal miR-21-5p mitigated post-CI inflammatory response through the PIK3R1/PI3K/AKT signaling axis and could offer neuroprotection after CI through promoting polarization of M2 microglia.

Cathodal bilateral transcranial direct-current stimulation regulates selenium to confer neuroprotection after rat cerebral ischaemia-reperfusion injury

Non-invasive transcranial direct-current stimulation (tDCS) is a safe ischaemic stroke therapy. Cathodal bilateral tDCS (BtDCS) is a modified tDCS approach established by us recently. Because selenium (Se) plays a crucial role in cerebral ischaemic injury, we investigated whether cathodal BtDCS conferred neuroprotection via regulating Se-dependent signalling in rat cerebral ischaemia-reperfusion (I/R) injury. We first showed that the levels of Se and its transport protein selenoprotein P (SEPP1) were reduced in the rat cortical penumbra following I/R, whereas cathodal BtDCS prevented the reduction of Se and SEPP1. Interestingly, direct-current stimulation (DCS) increased SEPP1 level in cultured astrocytes subjected to oxygen-glucose deprivation reoxygenation (OGD/R) but had no effect on SEPP1 level in OGD/R-insulted neurons, indicating that DCS may increase Se in ischaemic neurons by enhancing the synthesis and secretion of SEPP1 in astrocytes. We then revealed that DCS reduced the number of injured mitochondria in OGD/R-insulted neurons cocultured with astrocytes. DCS and BtDCS prevented the reduction of the mitochondrial quality-control signalling, vesicle-associated membrane protein 2 (VAMP2) and syntaxin-4 (STX4), in OGD/R-insulted neurons cocultured with astrocytes and the ischaemic brain respectively. Under the same experimental conditions, downregulation of SEPP1 blocked DCS- and BtDCS-induced upregulation of VAMP2 and STX4. Finally, we demonstrated that cathodal BtDCS increased Se to reduce infract volume following I/R. Together, the present study uncovered a molecular mechanism by which cathodal BtDCS confers neuroprotection through increasing SEPP1 in astrocytes and subsequent upregulation of SEPP1/VAMP2/STX4 signalling in ischaemic neurons after rat cerebral I/R injury. KEY POINTS: Cathodal bilateral transcranial direct-current stimulation (BtDCS) prevents the reduction of selenium (Se) and selenoprotein P in the ischaemic penumbra. Se plays a crucial role in cerebral ischaemia injury. Direct-current stimulation reduces mitochondria injury and blocks the reduction of vesicle-associated membrane protein 2 (VAMP2) and syntaxin-4 (STX4) in oxygen-glucose deprivation reoxygenation-insulted neurons following coculturing with astrocytes. Cathodal BtDCS regulates Se/VAMP2/STX4 signalling to confer neuroprotection after ischaemia.

Priming and Combined Strategies for the Application of Mesenchymal Stem Cells in Ischemic Stroke: A Promising Approach

Ischemic stroke (IS) is a leading cause of death and disability worldwide. Tissue plasminogen activator (tPA) administration and mechanical thrombectomy are the main treatments but have a narrow time window. Mesenchymal stem cells (MSCs), which are easily scalable in vitro and lack ethical concerns, possess the potential to differentiate into various types of cells and secrete a great number of growth factors for neuroprotection and regeneration. Moreover, MSCs have low immunogenicity and tumorigenic properties, showing safety and preliminary efficacy both in preclinical studies and clinical trials of IS. However, it is unlikely that MSC treatment alone will be sufficient to maximize recovery due to the low survival rate of transplanted cells and various mechanisms of ischemic brain damage in the different stages of IS. Preconditioning was used to facilitate the homing, survival, and secretion ability of the grafted MSCs in the ischemic region, while combination therapies are alternatives that can maximize the treatment effects, focusing on multiple therapeutic targets to promote stroke recovery. In this case, the combination therapy can yield a synergistic effect. In this review, we summarize the type of MSCs, preconditioning methods, and combined strategies as well as their therapeutic mechanism in the treatment of IS to accelerate the transformation from basic research to clinical application.

GW0742 reduces mast cells degranulation and attenuates neurological impairments via PPARβ/δ/CD300a/SHP1 pathway after GMH in neonatal rats

BACKGROUND

Activation of mast cells plays an important role in brain inflammation. CD300a, an inhibitory receptor located on mast cell surfaces, has been reported to reduce the production of pro-inflammatory cytokines and exert protective effects in inflammation-related diseases. Peroxisome proliferator-activated receptor β/δ (PPARβ/δ), a ligand-activated nuclear receptor, activation upregulates the transcription of CD300a. In this study, we aim to investigate the role of PPARβ/δ in the attenuation of germinal matrix hemorrhage (GMH)-induced mast cell activation via CD300a/SHP1 pathway.

METHODS

GMH model was induced by intraparenchymal injection of bacterial collagenase into the right hemispheric ganglionic eminence in P7 Sprague Dawley rats. GW0742, a PPARβ/δ agonist, was administered intranasally at 1 h post-ictus. CD300a small interfering RNA (siRNA) and PPARβ/δ siRNA were injected intracerebroventricularly 5 days and 2 days before GMH induction. Behavioral tests, Western blot, immunofluorescence, Toluidine Blue staining, and Nissl staining were applied to assess post-GMH evaluation.

RESULTS

Results demonstrated that endogenous protein levels of PPARβ/δ and CD300a were decreased, whereas chymase, tryptase, IL-17A and transforming growth factor β1 (TGF-β1) were elevated after GMH. GMH induced significant short- and long-term neurobehavioral deficits in rat pups. GW0742 decreased mast cell degranulation, improved neurological outcomes, and attenuated ventriculomegaly after GMH. Additionally, GW0742 increased expression of PPARβ/δ, CD300a and phosphorylation of SHP1, decreased phosphorylation of Syk, chymase, tryptase, IL-17A and TGF-β1 levels. PPARβ/δ siRNA and CD300a siRNA abolished the beneficial effects of GW0742.

CONCLUSIONS

GW0742 inhibited mast cell-induced inflammation and improved neurobehavior after GMH, which is mediated by PPARβ/δ/CD300a/SHP1 pathway. GW0742 may serve as a potential treatment to reduce brain injury for GMH patients.

Caveolin-1 aggravates neurological deficits by activating neuroinflammation following experimental intracerebral hemorrhage in rats

BACKGROUND

Intracerebral hemorrhage (ICH) is one of the stroke subtypes with the highest mortality. Secondary brain injury is associated with neurological dysfunction and poor prognosis after ICH. Caveolin-1 (CAV1) is the key protein of Caveolae. Previous studies have shown that CAV1 plays an important role in central nervous system diseases, and pointed out that in a collagenase-induced ICH model in vivo, CAV1 is associated with neuroinflammatory activation and poor neurological prognosis. In this study, we explore the role and the molecular mechanism of CAV1 in brain injury via a rat autologous whole blood injection model and an in vitro model of ICH.

METHODS

Adult male Sprague-Dawley rats ICH model was induced through autologous whole blood injecting into the right basal ganglia. The changes in protein levels of CAV1 in brain tissues of ICH rats were detected by western blot analysis. The immunofluorescent staining was used to explore the changes of CAV1 in microglia/macrophages (Iba1+ cells). Lentivirus vectors were administered by intracerebroventricular injection to induce CAV1 overexpression and knockdown respectively. The western blot analysis, immunofluorescence staining, enzyme-linked immunosorbent assay, terminal deoxynucleotidyl transferase dUTP nick end labeling and Nissl staining were performed to explore the role of CAV1 in secondary brain injury after ICH. Meanwhile, the rotarod test, foot fault test, adhesive-removal test, and Modified Garcia Test, as well as Morris Water Maze test, were performed to evaluate the behavioral cognitive impairment of ICH rats after genetic intervention. Additionally, BV-2 cells treated with oxygen hemoglobin for 24 h, were used as an in vitro model of ICH in this study to explore the molecular mechanism of CAV1 in brain injury; we performed western blot analysis after precise regulation of CAV1 in BV2 cells to observe changes in protein levels and phosphorylated levels of C-Src, IKK-β, and NF-κB.

RESULTS

The expression of CAV1 in microglia/macrophages (Iba1+ cells) was elevated and reached the peak at 24 h after ICH. CAV1 knockdown ameliorated ICH-induced neurological deficits, while CAV1 overexpression significantly worsened neurological dysfunction of ICH rats. CAV1 knockdown attenuated cellular apoptosis and promoted neuronal survival in brain tissues of ICH rats, while the ICH rats with CAV1 overexpression presented more cellular apoptosis and neuronal loss. Meanwhile, CAV1 knockdown inhibited the microglia activation and neuroinflammatory response, while CAV1 overexpression abolished these effects and aggravated neuroinflammation in brain tissues of ICH rats. Additionally, by inducing to CAV1 knockdown in BV2 cells in an in vitro model of ICH, the levels of p-C-Src, CAV-1, p-CAV-1, and p-IKK-β in cytoplasm and the level of NF-κB p65 in nucleus of BV2 cells were significantly decreased, while they were increased by inducing to CAV1 overexpression.

CONCLUSIONS

Our research revealed CAV1 aggravated neurological dysfunction in a rat ICH model. CAV1 knockdown exerted neuroprotective effect by suppressing microglia activation and neuroinflammation after ICH might via the C-Src/CAV1/IKK-β/NF-κB signaling pathway.

Glutamate excitotoxicity: Potential therapeutic target for ischemic stroke

Glutamate-mediated excitotoxicity is an important mechanism leading to post ischemic stroke damage. After acute stroke, the sudden reduction in cerebral blood flow is most initially followed by ion transport protein dysfunction and disruption of ion homeostasis, which in turn leads to impaired glutamate release, reuptake, and excessive N-methyl-D-aspartate receptor (NMDAR) activation, promoting neuronal death. Despite extensive evidence from preclinical studies suggesting that excessive NMDAR stimulation during ischemic stroke is a central step in post-stroke damage, NMDAR blockers have failed to translate into clinical stroke treatment. Current treatment options for stroke are very limited, and there is therefore a great need to develop new targets for neuroprotective therapeutic agents in ischemic stroke to extend the therapeutic time window. In this review, we highlight recent findings on glutamate release, reuptake mechanisms, NMDAR and its downstream cellular signaling pathways in post-ischemic stroke damage, and review the pathological changes in each link to help develop viable new therapeutic targets. We then also summarize potential neuroprotective drugs and therapeutic approaches for these new targets in the treatment of ischemic stroke.

Adipose-Derived Mesenchymal Stem Cells Combined With Extracellular Vesicles May Improve Amyotrophic Lateral Sclerosis

The complexity of central nervous system diseases together with their intricate pathogenesis complicate the establishment of effective treatment strategies. Presently, the superiority of adipose-derived mesenchymal stem cells (ADSCs) on neuronal injuries has attracted significant attention. Similarly, extracellular vesicles (EVs) are potential interventional agents that could identify and treat nerve injuries. Herein, we reviewed the potential effects of ADSCs and EVs on amyotrophic lateral sclerosis (ALS) injured nerves, and expound on their practical application in the clinic setting. This article predominantly focused on the therapeutic role of ADSCs concerning the pathogenesis of ALS, the protective and reparative effects of EVs on nerve injury, as well as the impact following the combined usage of ADSCs and EVs in ALS.

The Role of miRNAs in Dexmedetomidine's Neuroprotective Effects against Brain Disorders

There are limited neuroprotective strategies for various central nervous system conditions in which fast and sustained management is essential. Neuroprotection-based therapeutics have become an intensively researched topic in the neuroscience field, with multiple novel promising agents, from natural products to mesenchymal stem cells, homing peptides, and nanoparticles-mediated agents, all aiming to significantly provide neuroprotection in experimental and clinical studies. Dexmedetomidine (DEX), an α2 agonist commonly used as an anesthetic adjuvant for sedation and as an opioid-sparing medication, stands out in this context due to its well-established neuroprotective effects. Emerging evidence from preclinical and clinical studies suggested that DEX could be used to protect against cerebral ischemia, traumatic brain injury (TBI), spinal cord injury, neurodegenerative diseases, and postoperative cognitive disorders. MicroRNAs (miRNAs) regulate gene expression at a post-transcriptional level, inhibiting the translation of mRNA into functional proteins. In vivo and in vitro studies deciphered brain-related miRNAs and dysregulated miRNA profiles after several brain disorders, including TBI, ischemic stroke, Alzheimer’s disease, and multiple sclerosis, providing emerging new perspectives in neuroprotective therapy by modulating these miRNAs. Experimental studies revealed that some of the neuroprotective effects of DEX are mediated by various miRNAs, counteracting multiple mechanisms in several disease models, such as lipopolysaccharides induced neuroinflammation, β-amyloid induced dysfunction, brain ischemic-reperfusion injury, and anesthesia-induced neurotoxicity models. This review aims to outline the neuroprotective mechanisms of DEX in brain disorders by modulating miRNAs. We address the neuroprotective effects of DEX by targeting miRNAs in modulating ischemic brain injury, ameliorating the neurotoxicity of anesthetics, reducing postoperative cognitive dysfunction, and improving the effects of neurodegenerative diseases.

Efficacy of Human Adipose Derived Mesenchymal Stem Cells in Promoting Skin Wound Healing

Background

The aim of this pilot clinical study is to evaluate the efficacy of human adipose derived mesenchymal stem cells (HAMSCs) treatment for the wound healing with patients.

Methods

This study was a clinical trial to investigate the efficacy of human adipose derived mesenchymal stem cells treatment for the wound healing with patients. 346 patients with skin wounds attending the central hospital of Yue Yang were enrolled in the study, setting in the period from January 2016 to January 2021. Patients were randomly allocated into two groups: experimental group received treatment with human adipose derived mesenchymal stem cells for each 10 cm2 of wound and control group received conventional dressing with normal saline for each 10 cm2 of wound.

Results

No adverse events were recorded during the period of treatment. The granulation tissue coverage rate and thickness of granulation tissue after 10 days of treatment in experimental group were significantly improved compared with control group. Furthermore, the occurrence of bleeding of wound and suppurative wounds between two groups had significant difference (P < 0.05).

Conclusion

The data in this pilot study indicated that human adipose derived mesenchymal stem cells may be a safe and effective alternative therapy for wound healing. Moreover, larger, placebo-controlled, perspective studies are necessity to evaluate the efficacy and safety of human adipose derived mesenchymal stem cells treatment for wound healing patients.

Mesenchymal Stem Cells: Therapeutic Mechanisms for Stroke

Due to aging of the world’s population, stroke has become increasingly prevalent, leading to a rise in socioeconomic burden. In the recent past, stroke research and treatment have become key scientific issues that need urgent solutions, with a sharp focus on stem cell transplantation, which is known to treat neurodegenerative diseases related to traumatic brain injuries, such as stroke. Indeed, stem cell therapy has brought hope to many stroke patients, both in animal and clinical trials. Mesenchymal stem cells (MSCs) are most commonly utilized in biological medical research, due to their pluripotency and universality. MSCs are often obtained from adipose tissue and bone marrow, and transplanted via intravenous injection. Therefore, this review will discuss the therapeutic mechanisms of MSCs and extracellular vehicles (EVs) secreted by MSCs for stroke, such as in attenuating inflammation through immunomodulation, releasing trophic factors to promote therapeutic effects, inducing angiogenesis, promoting neurogenesis, reducing the infarct volume, and replacing damaged cells.

Lung Fibrosis Is Improved by Extracellular Vesicles from IFNγ-Primed Mesenchymal Stromal Cells in Murine Systemic Sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a severe autoimmune disease for which mesenchymal stromal cells (MSCs)-based therapy was reported to reduce SSc-related symptoms in pre-clinical studies. Recently, extracellular vesicles released by MSCs (MSC-EVs) were shown to mediate most of their therapeutic effect. Here, we aimed at improving their efficacy by increasing the MSC-EV dose or by IFNγ-priming of MSCs.

METHODS

small size (ssEVs) and large size EVs (lsEVs) were recovered from murine MSCs that were pre-activated using 1 or 20 ng/mL of IFNγ. In the HOCl-induced model of SSc, mice were treated with EVs at day 21 and sacrificed at day 42. Lung and skin samples were collected for histological and molecular analyses.

RESULTS

increasing the dose of MSC-EVs did not add benefit to the dose previously reported to be efficient in SSc. By contrast, IFNγ pre-activation improved MSC-EVs-based treatment, essentially in the lungs. Low doses of IFNγ decreased the expression of fibrotic markers, while high doses improved remodeling and anti-inflammatory markers. IFNγ pre-activation upregulated iNos, IL1ra and Il6 in MSCs and ssEVs and the PGE2 protein in lsEVs.

CONCLUSION

IFNγ-pre-activation improved the therapeutic effect of MSC-EVs preferentially in the lungs of SSc mice by modulating anti-inflammatory and anti-fibrotic markers.

Ephrin-B2 PB-mononuclear cells reduce early post-stroke deficit in diabetic mice but not long-term memory impairment

BACKGROUND AND PURPOSE

Post-stroke cognitive impairment (PSCI) has become a major public health issue, as a leading cause of dementia. The inflammation that develops soon after cerebral artery occlusion and may persist for weeks or months after stroke is a key component of PSCI. Our aim was to take advantage of the immunomodulatory properties of peripheral blood mononuclear cells (PB-MNC) stimulated with ephrin-B2/fc (PB-MNC⁺) for preventing PSCI.

METHODS

Cortical infarct was induced by thermocoagulation of the middle cerebral artery in male diabetic mice (streptozotocin IP). PB-MNC were isolated from diabetic human donors, washed with recombinant ephrin-B2/Fc and injected into the mice intravenously on the following day. Infarct volume, sensorimotor deficit, cell death and immune cell densities were assessed on day 3. Six weeks later, cognitive assessment was performed using the Barnes maze.

RESULTS

PB-MNC⁺ transplanted in post-stroke diabetic mice reduced the neurological deficit, infarct volume and apoptosis at D3, without modification of microglial cells, astrocytes and T-lymphocytes densities in the brain. Barnes maze assessment of memory showed that the learning, retention and reversal phases were not significantly modified by cell therapy.

CONCLUSIONS

Intravenous PB-MNC⁺ administration the day after stroke induction in diabetic mice improved sensorimotor deficit and reduced infarct volume at the short term, but was unable to prevent long-term memory loss. To what extent diabetes impacts on cell therapy efficacy will have to be specifically investigated in the future. Including vascular risk factors systematically in preclinical studies of cell therapy will provide a comprehensive understanding of the mechanisms potentially limiting cell efficacy and also to identify good and bad responders, particularly in the long term.

Strategies to Improve the Efficiency of Transplantation with Mesenchymal Stem Cells for the Treatment of Ischemic Stroke: A Review of Recent Progress

Cerebral ischemia is a common global disease that is characterized by a loss of neurological function and a poor prognosis in many patients. However, only a limited number of treatments are available for this condition at present. Given that the efficacies of these treatments tend to be poor, cerebral ischemia can create a significant burden on patients, families, and society. Mesenchymal stem cell (MSC) transplantation treatment has shown significant potential in animal models of ischemic stroke; however, the specific mechanisms underlying this effect have yet to be elucidated. Furthermore, clinical trials have yet to yield promising results. Consequently, there is an urgent need to identify new methods to improve the efficiency of MSC transplantation as an optimal treatment for ischemic stroke. In this review, we provide an overview of recent scientific reports concerning novel strategies that promote MSC transplantation as an effective therapeutic approach, including physical approaches, chemical agents, traditional Chinese medicines and extracts, and genetic modification. Our analyses showed that two key factors need to be considered if we are to improve the efficacy of MSC transplantation treatments: survival ability and homing ability. We also highlight the importance of other significant mechanisms, including the enhanced activation of MSCs to promote neurogenesis and angiogenesis, and the regulation of permeability in the blood-brain barrier. Further in-depth investigations of the specific mechanisms underlying MSC transplantation treatment will help us to identify effective methods that improve the efficiency of MSC transplantation for ischemic stroke. The development of safer and more effective methods will facilitate the application of MSC transplantation as a promising adjuvant therapy for the treatment of poststroke brain damage.

Stem Cell-Based Therapy for Experimental Ischemic Stroke: A Preclinical Systematic Review

Stem cell transplantation offers promise in the treatment of ischemic stroke. Here we utilized systematic review, meta-analysis, and meta-regression to study the biological effect of stem cell treatments in animal models of ischemic stroke. A total of 98 eligible publications were included by searching PubMed, EMBASE, and Web of Science from inception to August 1, 2020. There are about 141 comparisons, involving 5,200 animals, that examined the effect of stem cell transplantation on neurological function and infarct volume as primary outcome measures in animal models for stroke. Stem cell-based therapy can improve both neurological function (effect size, −3.37; 95% confidence interval, −3.83 to −2.90) and infarct volume (effect size, −11.37; 95% confidence interval, −12.89 to −9.85) compared with controls. These results suggest that stem cell therapy could improve neurological function deficits and infarct volume, exerting potential neuroprotective effect for experimental ischemic stroke, but further clinical studies are still needed.

Protective effects of mesenchymal stem cells on ischemic brain injury: therapeutic perspectives of regenerative medicine

Cerebral ischemic injury as the main manifestation of stroke can occur in stroke patients (70-80%). Nowadays, the main therapeutic strategy used for ischemic brain injury treatment aims to achieve reperfusion, neuroprotection, and neurorecovery. Also, angiogenesis as a therapeutic approach maybe represents a promising tool to enhance the prognosis of cerebral ischemic stroke. Unfortunately, although many therapeutic approaches as a life-saving gateway for cerebral ischemic injuries like pharmacotherapy and surgical treatments are widely used, they all fail to restore or regenerate damaged neurons in the brain. So, the suitable therapeutic approach would focus on regenerating the lost cells and restore the normal function of the brain. Currently, stem cell-based regenerative medicine introduced a new paradigm approach in cerebral ischemic injuries treatment. Today, in experimental researches, different types of stem cells such as mesenchymal stem cells have been applied. Therefore, stem cell-based regenerative medicine provides the opportunity to inquire and develop a more effective and safer therapeutic approach with the capability to produce and regenerate new neurons in damaged tissues.