miR-30b Promotes spinal cord sensory function recovery via the Sema3A/NRP-1/PlexinA1/RhoA/ROCK Pathway

TsMS combined with EA promotes functional recovery and axonal regeneration via mediating the miR-539-5p/Sema3A/PlexinA1 signalling axis in sciatic nerve-injured rats

Enhancing axonal regeneration is one of the most important processes in treating nerve injuries. Both magnetic and electrical stimulation have the effect of promoting nerve axon regeneration. But few study has investigated the effects of trans-spinal magnetic stimulation (TsMS) combined with electroacupuncture (EA) on nerve regeneration in rats with sciatic nerve injury. In this study, we compared the improvement of neurological function in rats with sciatic nerve crush injuries after 4 weeks of different interventions (EA, TsMS, or TsMS combined with EA). We further explored the morphological and molecular biological alterations following sciatic nerve injury by HE, Masson, RT-PCR, western blotting, immunofluorescence staining and small RNA transcriptome sequencing. The results showed that TsMS combined with EA treatment significantly promoted axonal regeneration, increased the survival rate of neurons, and suppressed denervation atrophy of the gastrocnemius muscle. Subsequent experiments suggested that the combination treatment may play an active role by mediating the miR-539-5p/Sema3A/PlexinA1 signaling axis.

The role and mechanisms of mesenchymal stem cells regulating macrophage plasticity in spinal cord injury

Spinal Cord Injury (SCI) is a devastating neurological disorder comprising primary mechanical injury and secondary inflammatory response-mediated injury for which an effective treatment is still unavailable. It is well known that secondary inflammatory responses are a significant cause of difficulties in neurological recovery. An immune imbalance between M1/M2 macrophages at the sites of injury is involved in developing and progressing the secondary inflammatory response. Recently, Mesenchymal Stem Cells (MSCs) have shown significant therapeutic potential in tissue engineering and regenerative medicine due to their potential multidirectional differentiation and immunomodulatory properties. Accumulating evidence shows that MSCs can regulate the balance of M1/M2 macrophage polarization, suppress downstream inflammatory responses, facilitate tissue repair and regeneration, and improve the prognosis of SCI. This article briefly overviews the impact of macrophages and MSCs on SCI and repair. It discusses the mechanisms by which MSCs regulate macrophage plasticity, including paracrine action, release of exosomes and apoptotic bodies, and metabolic reprogramming. Additionally, the article summarizes the relevant signaling pathways of MSCs that regulate macrophage polarization.

Focal ischemic stroke modifies microglia-derived exosomal miRNAs: potential role of mir-212-5p in neuronal protection and functional recovery

BACKGROUND

Ischemic stroke is a severe type of stroke with high disability and mortality rates. In recent years, microglial exosome-derived miRNAs have been shown to be promising candidates for the treatment of ischemic brain injury and exert neuroprotective effects. Mechanisms underlying miRNA dysregulation in ischemic stroke are still being explored. Here, we aimed to verify whether miRNAs derived from exosomes exert effects on functional recovery.

METHODS

MiR-212-5p agomir was employed to upregulate miR-212-5p expression in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R) as well as an oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro. Western blot analysis, qRT-PCR and immunofluorescence staining and other methods were applied to explore the underlying mechanisms of action of miR-212-5p.

RESULTS

The results of our study found that intervention with miR-212-5p agomir effectively decreased infarct volume and restored motor function in MCAO/R rats. Mechanistically, miR-212-5p agomir significantly reduced the expression of PlexinA2 (PLXNA2). Additionally, the results obtained in vitro were similar to those achieved in vivo.

CONCLUSION

In conclusion, the present study indicated that PLXNA2 may be a target gene of miR-212-5p, and miR-212-5p has great potential as a target for the treatment and diagnosis of ischemic stroke.

IGF-1 Combined with OPN Promotes Neuronal Axon Growth in Vitro Through the IGF-1R/Akt/mTOR Signaling Pathway in Lipid Rafts

This study aims to investigate the effect of insulin-like growth factor 1 (IGF-1) combined with osteopontin (OPN) on the protein expression levels and growth of neuronal axons and its possible mechanism. In this study, IGF-1 combined with OPN promoted neuronal axon growth through the IGF-1R/Akt/mTOR signaling pathway in lipid rafts, and the effect was better than that of either agent alone. This effect was suppressed when given the mTOR inhibitor rapamycin or the lipid raft cholesterol extraction agent methyl-β-cyclodextrin (M-β-CD). Rapamycin could inhibit the expression of phosphorylated ribosomal S6 protein (p-S6) and phosphorylated protein kinase B (p-Akt) and limit axon growth. In addition to the above effects, M-β-CD significantly downregulated the expression of phosphorylated insulin-like growth factor 1 receptor (p-IR). To further investigate the changes in lipid rafts when stimulated by different recombinant proteins, membrane lipid rafts were isolated to observe the changes by western blot. The expression levels of insulin-like growth factor 1 receptor (IR) and P-IR in the IGF-1 combined with OPN group were the highest. When M-β-CD was administered to the lipid rafts of neurons, the enrichment of IR by IGF-1 combined with OPN was weakened, and the p-IR was decreased. Our study found that IGF-1 combined with OPN could promote axon growth by activating the IGF-1R/Akt/mTOR signaling pathway in neuronal lipid rafts.

GLP-1 rescued gestational diabetes mellitus-induced suppression of fetal thalamus development

Diabetes can be classified as type 1, type 2, and gestational diabetes mellitus (GDM). It has been reported that children born from mothers with GDM present motor impairment, however, underlying mechanisms of GDM-induce fetal neurological diseases remain unknown. In this study, NOD (nonobese diabetic) mice were used to construct the GDM model; after 2 weeks of gestation, thalamocortical axon development of fetal was evaluated by immunofluorescence. PCR of LRRC4C was used to confirm axon development of the thalamus cortex. RNA array was used to predict possible targets affected by GDM during fetal neurodevelopment. Western blot was used to investigate the underlying mechanism, PI3K inhibitor, and MAPK inhibitor was used to determine key pathway involved in this model, in vitro axonal growth was evaluated using neural stem cells, tactile sensory behavior of offspring was assessed to confirm neurological influence further. The result shown that maternal diabetes significantly suppressed axonal development of fetal thalamus cortex, PCR array of GDM fetal brain indicated that upregulation of GLP-1R compared with normal fetal, ELISA confirmed that GLP-1 level was decreased in GDM maternal serum compared with that of wild type pregnant mice. In vitro study observed enhanced axonal elongation after supplements of GLP-1 analog, GLP-1 analog PI3K-dependently active ROCK1 activity, IP injection of GLP-1 analog could partly reverse GDM-induced suppression of fetal thalamocortical axon development and improve tactile sensory behavior of GDM offspring. Our study provided a novel mechanism of GDM induced-neurological diseases and predicted GLP-1 as possible prevention supplement during gestation.

Investigation of Naoluoxintong on the neural stem cells by facilitating proliferation and differentiation in vitro and on protecting neurons by up-regulating the expression of nestin in MCAO rats

ETHNOPHARMACOLOGICAL RELEVANCE

The classic traditional Chinese compound Naoluoxintong (NLXT) has been proven an effective remedy for ischemic stroke (IS). The protective effect of NLXT on neural stem cells (NSCs), however, remains unclear.

AIM OF THE STUDY

To investigate the protective effect of NLXT on NSCs in rats with middle cerebral artery occlusion (MCAO) and the effect of Nestin expression in vivo.

MATERIALS AND METHODS

Sprague-Dawley (SD) rats were randomly divided into three groups: the sham-operated group, the MCAO model group and the NLXT group. The MCAO model in rats was established by modified Longa wire embolization method. The sham-operated group, the model group and the NLXT groups were divided into three subgroups according to the sampling time points of 1 d, 3 d and 7 d after successful model-making. Immunofluorescence staining, including bromodeoxyuridine (BrdU)/glial fibrillary acidic protein (GFAP), β-tubulinIII/GFAP, BrdU/doublecortin (DCX) and BrdU/neuronal nuclei (NeuN), was used to detect the proliferation and survival of NSCs in the hippocampal after drug administration. Protein expression of Nestin, DCX, GFAP and NeuN in the hippocampal was detected by Western blot (WB).

RESULTS

Immunofluorescence experiment of Nestin labeled: on the first day, a few Nestin-positive cells were found in the hippocampal DG area. Afterwards, the number of Nestin-labeled positive cells in the model group increased, while the number of cells in the sham group did not fluctuate significantly. The number of positive cells in each administration group increased more than that in the model and normal group. β-tubulin III/GFAP double-labeled: a small amount of double labeled cells was expressed in the normal group, and the number subsequently fluctuated little. In the model group, β-tubulin III/GFAP positive cells increased initially after acute ischemia, and gradually decreased afterwards. In the NLXT-treated group, β-Tubulin III positive cells were significantly increased on day 1, 3 and 7, while GFAP positive cells had little change. BrdU/DCX double-labeled: initially, a small number of BrdU/DCX-labeled positive cells were observed in the normal group and the model group, but there was no increasing trend over time. The positive cells in the NLXT group increased over time, and those in the seven-day group were significantly higher than those in the one-day and three-day groups. BrdU/NEUN double-labeled: in the normal group, BrdU/NEUN positive cells were enriched and distributed regularly. The number of positive cells in the model group was small and decreased gradually with time, and the decrease was most obvious on the third day. The number of positive cells in the NLXT group was significantly higher than that in the model group, and the number of positive cells in the seven-day group was significantly higher than that in the one-day and three-day groups. WB results reflected those three proteins, Nestin, NeuN and DCX, showed an increase in expression, except GFAP, which showed a decreasing trend.

CONCLUSIONS

Preliminarily, NLXT can promote the migration and differentiation of NSCs. It may have a protective effect on the brain by promoting repair of brain tissue damage through upregulation of Nestin after IS.

Integrated bioinformatics analysis identifies the effects of Sema3A/NRP1 signaling in oligodendrocytes after spinal cord injury in rats

Objective

To investigate the effect of Sema3A/NRP1 signaling in oligodendrocytes (OLs) after spinal cord injury.

Methods

Three analysis strategies, namely differential expression gene analysis, Gene Ontology (GO) enrichment, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, were applied. The protein-protein interaction (PPI) network was constructed using the STRING website to explore the correlation between Sema3A/NRP1 and oligodendrocytes. Then, the T10 spinal cord segment of rats was injured by the Allen method to establish a spinal cord injury (SCI) model. Real-time quantitative PCR, Western blotting, Nissl staining and immunofluorescence staining were used to detect the effect of Sema3A/NRP1 signaling on oligodendrocytes in vivo.

Results

After the SCI model was established, significantly fewer oligodendrocytes were observed. At the same time, R software was used to analyze the expression of related genes, and NRP1 expression was increased. PCR also demonstrated similar results, and NRP1 ligand Sema3A was also upregulated. KEGG and GO functional enrichment analysis indicated that the SCI model was mainly related to cytokine interaction, cell proliferation, differentiation and maturation. Interestingly, we found that NRP1 was involved in semaphorin-plexin signaling pathway neuronal projection guidance and axon guidance, mediating cell growth and migration. Moreover, Sema3A/NRP1 signaling was closely associated with platelet-derived growth factor receptor α (PDGFRα) in the PPI network. When Sema3A/NRP1 signaling was specifically blocked at early stages, PDGFRα expression was effectively inhibited, and the expression of OLs was promoted. Furthermore, inhibition of Sema3A/NRP1 signaling increased the Basso-Beattie-Bresnahan (BBB) score of lower limb motor function in SCI rats and promoted the survival of motor neurons in the ventral horn of the injured spinal cord.

Conclusion

Our data suggest that Sema3A/NRP1 signaling may regulate the development of OPCs and OLs after SCI, thereby affecting functional recovery.

Loureirin A Exerts Antikeloid Activity by Antagonizing the TGF-β1/Smad Signalling Pathway

It has been recently shown that loureirin A (LA), a major active component of resina draconis, might be effective in the prevention and treatment of liver fibrosis. We examined whether LA could inhibit the formation of keloids. To investigate the pharmacological effects of loureirin A on keloid formation and the underlying mechanisms. CellTiter-Blue viability assays were used to examine the proliferation of keloid fibroblasts (KFs) that were treated with LA. Fibroblast migration was evaluated using a cell migration assay. Immunofluorescence staining was used to measure the expression of α-SMA in KFs. RT-qPCR was used to evaluate the mRNA expression of Col-I, Col-III, α-SMA, Bax, and Caspase-3, while Western blotting was used to evaluate the protein expression of Col-I, Col-III, α-SMA, Bax, Caspase-3, p-Smad2, and p-Smad3. LA inhibited the proliferation of KFs and suppressed the migration and TGF-β1-induced myofibroblast differentiation of KFs. In addition, LA downregulated the mRNA and protein levels of Col-I, Col-III, and α-SMA while promoting the mRNA and protein levels of Bax and Caspase-3. Moreover, LA downregulated the protein levels of p-Smad2 and p-Smad3 in cultured TGF-β1-treated KFs ex vivo. These results show that LA has an antikeloid effect on KFs by suppressing the TGF-β1/Smad signalling pathway. Our findings suggest that LA may be a potential candidate drug for the prevention and treatment of keloids.

MiRNAs as Promising Translational Strategies for Neuronal Repair and Regeneration in Spinal Cord Injury

Spinal cord injury (SCI) represents a devastating injury to the central nervous system (CNS) that is responsible for impaired mobility and sensory function in SCI patients. The hallmarks of SCI include neuroinflammation, axonal degeneration, neuronal loss, and reactive gliosis. Current strategies, including stem cell transplantation, have not led to successful clinical therapy. MiRNAs are crucial for the differentiation of neural cell types during CNS development, as well as for pathological processes after neural injury including SCI. This makes them ideal candidates for therapy in this condition. Indeed, several studies have demonstrated the involvement of miRNAs that are expressed differently in CNS injury. In this context, the purpose of the review is to provide an overview of the pre-clinical evidence evaluating the use of miRNA therapy in SCI. Specifically, we have focused our attention on miRNAs that are widely associated with neuronal and axon regeneration. “MiRNA replacement therapy” aims to transfer miRNAs to diseased cells and improve targeting efficacy in the cells, and this new therapeutic tool could provide a promising technique to promote SCI repair and reduce functional deficits.

Rho/ROCK Pathway and Noncoding RNAs: Implications in Ischemic Stroke and Spinal Cord Injury

Ischemic strokes (IS) and spinal cord injuries (SCI) are major causes of disability. RhoA is a small GTPase protein that activates a downstream effector, ROCK. The up-regulation of the RhoA/ROCK pathway contributes to neuronal apoptosis, neuroinflammation, blood-brain barrier dysfunction, astrogliosis, and axon growth inhibition in IS and SCI. Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), were previously considered to be non-functional. However, they have attracted much attention because they play an essential role in regulating gene expression in physiological and pathological conditions. There is growing evidence that ROCK inhibitors, such as fasudil and VX-210, can reduce injury in IS and SCI in animal models and clinical trials. Recently, it has been reported that miRNAs are decreased in IS and SCI, while lncRNAs are increased. Inhibiting the Rho/ROCK pathway with miRNAs alleviates apoptosis, neuroinflammation, oxidative stress, and axon growth inhibition in IS and SCI. Further studies are required to explore the significance of ncRNAs in IS and SCI and to establish new strategies for preventing and treating these devastating diseases.

miR-30b Promotes spinal cord sensory function recovery via the Sema3A/NRP-1/PlexinA1/RhoA/ROCK Pathway

Spinal cord injury (SCI) induces both motor and sensory dysfunctions. We wondered whether miR-30b could promote primary sensory neuron (PSN) axon growth in inhibitory microenvironment. The neurite growth was promoted by miR-30b agomir and inhibited by antagomir. MiR-30b targeted and degraded sema3A mRNA. MiR-30b regulated the formation of sema3A-NRP-1-PlexinA1 complex via targeting sema3A. The neurite length was induced by the miR-30b agomir, and the application of sema3A protein could reverse the effect of agomir. GTP-RhoA and ROCK expression were down-regulated by miR-30b. Neurite outgrowth that inhibited by sema3A and the miR-30b antagomir was increased by Y-27632. Agomir promoted neurite growth in NogoA inhibitory conditions, which indicated miR-30b could both enhance neuronal intrinsic regenerative ability and promote neurite growth against inhibitory microenvironment via Sema3A/NRP-1/PlexinA1/RhoA/ROCK axis. The agomir could also regulate Sema3A/NRP-1/PlexinA1/RhoA/ROCK axis in vivo and restore spinal cord sensory conductive function. In conclusion, miR-30b could be a novel target for sensation recovery after SCI.