Background/Aims: Neurotoxic A1 astrocytes are induced by inflammation after spinal cord injury (SCI), and the inflammation-related Nuclear Factor Kappa B (NFκB) pathway may be related to A1-astrocyte activation. Mesenchymal stem cell (MSC) transplantation is a promising therapy for SCI, where transplanted MSCs exhibit anti-inflammatory effects by downregulating proinflammatory factors, such as Tumor Necrosis Factor (TNF)-α and NFκB. MSC-exosomes (MSC-exo) reportedly mimic the beneficial effects of MSCs. Therefore, in this study, we investigated whether MSCs and MSC-exo exert inhibitory effects on A1 astrocytes and are beneficial for recovery after SCI. Methods: The effects of MSC and MSC-exo on SCIinduced A1 astrocytes, and the potential mechanisms were investigated in vitro and in vivo using immunofluorescence and western blot. In addition, we assessed the histopathology, levels of proinflammatory cytokines and locomotor function to verify the effects of MSC and MSC-exo on SCI rats. Results: MSC or MSC-exo co-culture reduced the proportion of SCIinduced A1 astrocytes. Intravenously-injected MSC or MSC-exo after SCI significantly reduced the proportion of A1 astrocytes, the percentage of p65 positive nuclei in astrocytes, and the percentage of TUNEL-positive cells in the ventral horn. Additionally, we observed decreased lesion area and expression of TNFα, Interleukin (IL)-1α and IL-1β, elevated expression of Myelin Basic Protein (MBP), Synaptophysin (Syn) and Neuronal Nuclei (NeuN), and improved Basso, Beattie & Bresnahan (BBB) scores and inclined-plane-test angle. In vitro assay showed that MSC and MSC-exo reduced SCI-induced A1 astrocytes, probably via inhibiting the nuclear translocation of the NFκB p65. Conclusion: MSC and MSC-exo reduce SCI-induced A1 astrocytes, probably via inhibiting nuclear translocation of NFκB p65, and exert antiinflammatory and neuroprotective effects following SCI, with the therapeutic effect of MSCexo comparable with that of MSCs when applied intravenously.

Mesenchymal stem cell (MSC) transplantation has been shown to represent a potential treatment for traumatic spinal cord injury (SCI). However, there are several obstacles that need to be overcome before MSCs can be considered for clinical application, such as failure of MSCs to reach the spinal cord lesion core and possible tumor formation. Recent studies have suggested that MSC treatment is beneficial owing to paracrine-secreted factors. Extracellular vesicles are considered to be some of the most valuable paracrine molecules. However, the therapeutic mechanism of extracellular vesicles on spinal cord injury has not been studied clearly. Therefore, our study investigated the effect of systemic administration of extracellular vesicles on the loss of motor function after SCI and examined the potential mechanisms underlying their effects. Disruption of the blood-spinal cord barrier (BSCB) is a crucial factor that can be detrimental to motor function recovery. Pericytes are an important component of the neurovascular unit, and play a pivotal role in maintaining the structural integrity of the BSCB. Our study demonstrated that administration of bone mesenchymal stem cell-derived extracellular vesicles (BMSC-EV) reduced brain cell death, enhanced neuronal survival and regeneration, and improved motor function compared with the administration of BMSC-EV free culture media (EV-free CM). Besides, the BSCB was attenuated and pericyte coverage was significantly decreased in vivo. Furthermore, we found that exosomes reduced pericyte migration via downregulation of NF-κB p65 signaling, with a consequent decrease in the permeability of the BSCB. In summary, we identified that extracellular vesicles treatment suppressed the migration of pericytes and further improved the integrity of the BSCB via NF-κB p65 signaling in pericytes. Our data suggest that extracellular vesicles may serve as a promising treatment strategy for SCI.

Widespread death of transplanted mesenchymal stem cells (MSCs) hampers the development of stem cell therapy for Alzheimer disease (AD). Cell pre-conditioning might help cope with this challenge. We tested whether let-7f-5p-modified MSCs could prolong the survival of MSCs after transplantation. When exposed to Aβ25−35 in vitro, MSCs showed significant early apoptosis with decrease in the let-7f-5p levels and increased caspase-3 expression. Upregulating microRNA let-7f-5p in MSCs alleviated Aβ25−35-induced apoptosis by decreasing the caspase-3 levels. After computerized analysis and the luciferase reporter assay, we identified that caspases-3 was the target gene of let-7f-5p. In vivo, hematoxylin and eosin staining confirmed the success of MSCs transplantation into the lateral ventricles, and the let-7f-5p upregulation group showed the lowest apoptotic rate of MSCs detected by TUNEL immunohistochemistry analysis and immunofluorescence. Similarly, bioluminescent imaging showed that let-7f-5p upregulation moderately prolonged the retention of MSCs in brain. In summary, we identified the anti-apoptotic role of let-7f-5p in Aβ25−35-induced cytotoxicity, as well as the protective effect of let-7f-5p on survival of grafted MSCs by targeting caspase-3 in AD models. These findings show a promising approach of microRNA-modified MSCs transplantation as a therapy for neurodegenerative diseases.

BackgroundNeural stem cells (NSCs) are able to differentiate into neurons and astroglia. miRNAs have been demonstrated to be involved in NSC self-renewal, proliferation and differentiation. However, the exact role of miR-124 in the development of NSCs and its underlying mechanism remain to be explored.MethodsPrimary NSCs were isolated from embryos of Wistar rats. Immunocytochemistry was used to stain purified NSCs. miR-124, Delta-like 4 (DLL4), ki-67, Nestin, β-tubulin III, glial fibrillary acidic protein (GFAP), HES1, HEY2, and cyclin D1 (CCND1) expressions were detected by qRT-PCR and western blot. The interaction between miR-124 and DLL4 was confirmed by luciferase reporter assay. Cell proliferation was assessed by MTT assay.ResultsNSCs could self-proliferate and differentiate into neurons and astrocyte. miR-124 was up-regulated and DLL4 was down-regulated during NSC differentiation. DLL4 was identified as a target of miR-124 in NSCs. Ectopic expression of miR-124 or knockdown of DLL4 promoted the proliferation and the formation of NSCs to neurospheres. Moreover, miR-124 overexpression or DLL4 down-regulation improved β-tubulin III expression but decreased GFAP expression in NSCs. Furthermore, enforced expression of DLL4 partially reversed the effects of miR-124 on NSCs proliferation and differentiation. Elevated expression of miR-124 suppressed the expressions of HES1, HEY2, and CCND1 in NSCs, while these effects were attenuated following the enhancement of DLL4 expression.ConclusionmiR-124 promoted proliferation and differentiation of NSCs through inactivating Notch pathway.

Neural stem cells (NSCs) are multipotent and undifferentiated cells with the potential to differentiate into neuronal lineages and gliocytes. NSCs have the ability to generate and regenerate the brain, indicating the possibility of cell-based therapies for neurological disorders. miR-124 has been demonstrated as a modulator in the survival, expansion, and differentiation of NSCs. However, the underlying molecular mechanisms of miR-124 in NSC development are still far from being understood. The expressions of miR-124, dishevelled binding antagonist of beta-catenin 1 (DACT1), ki-67, Nestin, β-tubulin III, glial fibrillary acidic protein (GFAP), β-catenin, cyclinD1, and glycogen synthase kinase-3β (GSK-3β) were examined by qRT-PCR or western blot. Bioinformatics and Dual-Luciferase reporter assay were used to identify the interaction between miR-124 and DACT1. MTS analysis was performed to measure the viability of NSCs. Enhanced expression of miR-124 and lowered expression of DACT1 were observed during a 14-day NSC differentiation period. DACT1 was verified as a direct target of miR-124. Moreover, overexpression of miR-124 promoted NSC proliferation and induced neuron-specific differentiation, presented as increased cell viability, higher neurosphere number, elevated ki-67, Nestin, β-tubulin III expressions, and decreased GFAP expression. Similarly, DACT1 downregulation facilitated proliferation and neuronal differentiation of NSCs. Furthermore, DACT1 overexpression impaired miR-124-induced proliferation and differentiation of NSCs. Additionally, miR-124 stimulated Wnt/β-catenin signaling via suppressing DACT1 expression. miR-124 promoted proliferation and induced NSC differentiation to neurons by activation of Wnt/β-catenin pathway via targeting DACT1, providing a potential target and aiding the development of cell-based therapies for neurological disorders.

microRNAs are a class of non-coding RNAs including approximately 22 nucleotides in length and play a pivotal role in post-transcriptional gene regulation. Currently, the role of miRNAs in the pathophysiology of ischemic stroke has been the subject of recent investigations. In particular, antagomirs to microRNA (miRNA) let-7f have been found to be neuroprotective in vivo, although the detailed function of let-7f during cerebral ischemia has not been fully illustrated. NDRG3 is an N-myc downstream-regulated gene (NDRG) family member that has been observed in the nuclei in most brain cells. Recently, a NDRG3-mediated lactate signaling, in which stabilized NDRG3 protein can promote angiogenesis and cell growth by activating the Raf-ERK pathway in hypoxia was discovered. In this study, we preliminarily explored the change in the expression of the NDRG3 protein which indicated that NDRG3 protein is an oxygen-regulated protein in neurons in rat cerebral ischemia in vivo and in vitro. We further identified let-7f as an upstream regulator of NDRG3 by the lentiviral transfection of rat cortical neurons and the dual luciferase analysis of human genes. In addition, a dual-color fluorescence in situ hybridization assay showed that when the expression of let-7f was elevated, the expression of NDRG3 mRNA was accordingly reduced in rat cerebral ischemia. Taken together, our results identify a new regulatory mechanism of let-7f on NDRG3 expression in the hypoxic response of cerebral ischemia and raise the possibility that the let-7f/NDRG3 pathway may serve as a potential target for the treatment of ischemic stroke.

Purpose: To investigate the relationship between the neutrophil-to-lymphocyte ratio (NLR) and the severity of neurological impairment at disease onset in patients with a first episode of neuromyelitis optica spectrum disorder (NMOSD). Patients and Methods: This retrospective study included 259 patients with newly diagnosed NMOSD who were hospitalized at our institution between January 2013 and January 2020 (NMOSD group) and 169 healthy control subjects who underwent a physical examination at our hospital during the same period (control group). The clinical data collected included general information, past medical history, biochemical test results, imaging findings, NLR, AQP-4 antibody status, and initial Expanded Disability Status Scale score. A logistic regression model was used to analyze NLR as an independent risk factor for the severity of neurological impairment at disease onset in the NMOSD group. Receiver-operating characteristic curve analysis was used to evaluate the ability of the NLR to predict the severity of neurological impairment at disease onset in the NMOSD group and to determine its critical value. Results: The NLR was significantly higher in the NMOSD group than in the control group (P<0.001). In the NMOSD group, neurological impairment at disease onset was more severe in those with a high NLR than in those with a low NLR (P<0.001). At onset of disease, patients with severe neurological impairment had a more significant increase in NLR than those with mild-to-moderate neurological impairment (P<0.001). Both univariate (OR 1.180, 95% CI 1.046-1.331, P=0.007) and multivariate (OR 1.146, 95% CI 1.003-1.308, P=0.044) logistic regression analyses showed that the NLR was positively correlated with the severity of neurological impairment at onset of disease in the NMOSD group. The area under the receiver-operating characteristic curve was 0.687. Conclusion:The NLR is an independent risk factor for the severity of neurological impairment at disease onset in patients with a first episode of NMOSD.

Objective: To investigate prospective associations between triglyceride (TG) level and prognosis of first-attacked patients with neuromyelitis optica spectrum disorders (NMOSD).Methods: This retrospective study included 196 patients newly diagnosed with NMOSD from June 2014 to December 2018. Data of clinical parameters, including age of onset, sex, BMI, blood lipid levels, anti-aquaporin-4 status, serum glucose level, therapy regimens, comorbidities, initial Expanded Disability Status Scale (EDSS), relapses, and outcomes were collected. We used logistic regression models to examine the associations among relevant clinical factors and outcomes, and statistical analyses were performed using the SPSS 23.0 software.Results: Compared with the high TG group, residual EDSS was relatively lower in the normal TG group (median 1.0 vs. 2.0, P = 0.002). In the univariate analysis, TG level was positively correlated with outcomes (OR 1.75, 95% CI 1.18–2.60, P = 0.005) and relapses (OR 1.57, 95% CI 1.07–2.31, P = 0.02). Our stratified analysis suggested that patients with normal BMI (OR 4.90, 95% CI 2.10–11.44, P = 0.001) were closely correlated with poor recovery owing to increased TG level. In the multivariate analysis, a statistically significant association still existed between TG level and outcomes (OR 3.44, 95% CI 1.02–11.64; P = 0.040) after adjusting for various variables.Conclusions: In first-attacked NMOSD patients, TG level was positively associated with poor recovery. Early monitoring and treatment of elevated TG level in NMOSD patients are important.