Proteomic Analysis of the Peri-Infarct Area after Human Umbilical Cord Mesenchymal Stem Cell Transplantation in Experimental Stroke

A systematic review and in silico analysis of studies investigating the ischaemic penumbra proteome in animal models of experimental stroke

Ischaemic stroke results in the formation of a cerebral infarction bordered by an ischaemic penumbra. Characterising the proteins within the ischaemic penumbra may identify neuro-protective targets and novel circulating markers to improve patient care. This review assessed data from studies using proteomic platforms to compare ischaemic penumbra tissues to controls following experimental stroke in animal models. Proteins reported to differ significantly between penumbra and control tissues were analysed in silico to identify protein-protein interactions and over-represented pathways. Sixteen studies using rat (n = 12), mouse (n = 2) or primate (n = 2) models were included. Heterogeneity in the design of the studies and definition of the penumbra were observed. Analyses showed high abundance of p53 in the penumbra within 24 hours of permanent ischaemic stroke and was implicated in driving apoptosis, cell cycle progression, and ATM- MAPK- and p53- signalling. Between 1 and 7 days after stroke there were changes in the abundance of proteins involved in the complement and coagulation pathways. Favourable recovery 1 month after stroke was associated with an increase in the abundance of proteins involved in wound healing. Poor recovery was associated with increases in prostaglandin signalling. Findings suggest that p53 may be a target for novel therapeutics for ischaemic stroke.

Identification of Novel Circulating miRNAs in Patients with Acute Ischemic Stroke

Ischemic strokes are associated with significant morbidity and mortality, but currently there are no reliable prognostic or diagnostic blood biomarkers. MicroRNAs (miRNAs) regulate various molecular pathways and may be used as biomarkers. Using RNA-Seq, we conducted comprehensive circulating miRNA profiling in patients with ischemic stroke compared with healthy controls. Samples were collected within 24 h of clinical diagnosis. Stringent analysis criteria of discovery (46 cases and 95 controls) and validation (47 cases and 96 controls) cohorts led to the identification of 10 differentially regulated miRNAs, including 5 novel miRNAs, with potential diagnostic significance. Hsa-miR-451a was the most significantly upregulated miRNA (FC; 4.8, FDR; 3.78 × 10⁻⁸⁵), while downregulated miRNAs included hsa-miR-574-5p and hsa-miR-142-3p, among others. Importantly, we computed a multivariate classifier based on the identified miRNA panel to differentiate between ischemic stroke patients and healthy controls, which showed remarkably high sensitivity (0.94) and specificity (0.99). The area under the ROC curve was 0.97 and it is superior to other current available biomarkers. Moreover, in samples collected one month following stroke, we found sustained upregulation of hsa-miR-451a and downregulation of another 5 miRNAs. Lastly, we report 3 miRNAs that were significantly associated with poor clinical outcomes of stroke, as defined by the modified Rankin scores. The clinical translation of the identified miRNA panel may be explored further.

Use of ATP-Binding Cassette Subfamily A Member 13 (ABCA13) for Sensitive Detection of Focal Pathological Forms of Subclinical Bovine Paratuberculosis

Bovine paratuberculosis (PTB) is a chronic enteritis caused by Mycobacterium avium subspecies paratuberculosis (Map) that causes a heavy economic impact worldwide. Map infected animals can remain asymptomatic for years while transmitting the mycobacteria to other members of the herd. Therefore, accurate detection of subclinically infected animals is crucial for disease control. In a previous RNA-Seq study, we identified several mRNAs that were overexpressed in whole blood of cows with different PTB-associated histological lesions compared with control animals without detected lesions. The proteins encoded by two of these mRNAs, ATP binding cassette subfamily A member 13 (ABCA13) and Matrix Metallopeptidase 8 (MMP8) were significantly overexpressed in whole blood of animals with focal histological lesions, the most frequent pathological form in the subclinical stages of the disease. In the current study, the potential of sensitive early diagnostic tools of commercial ELISAs, based on the detection of these two biomarkers, was evaluated in serum samples of 704 Holstein Friesian cows (566 infected animals and 138 control animals from PTB-free farms). For this evaluation, infected animals were classified into three groups, according to the type of histological lesions present in their gut tissues: focal (n = 447), multifocal (n = 59), and diffuse (n = 60). The ELISA based on the detection of ABCA13 was successfully validated showing good discriminatory power between animals with focal lesions and control animals (sensitivity 82.99% and specificity 80.43%). Conversely, the MMP8-based ELISA showed a poor discriminatory power between the different histological groups and non-infected controls. The ABCA13-based ELISA showed a higher diagnostic value (0.822) than the IDEXX ELISA (0.517), the fecal bacterial isolation (0.523) and the real-time PCR (0.531) for the detection of animals with focal lesions. Overall, our results indicate that this ABCA13 ELISA greatly improves the identification of subclinically infected animals with focal lesions that are undetectable using current diagnostic methods.

Synthetic VSMCs induce BBB disruption mediated by MYPT1 in ischemic stroke

Vascular smooth muscle cells (VSMCs) have been widely recognized as key players in regulating blood-brain barrier (BBB) function, and their roles are unclear in ischemic stroke. Myosin phosphatase target subunit 1 (MYPT1) is essential for VSMC contraction and maintaining healthy vasculature. We generated VSMC-specific MYPT1 knockout (MYPT1^SMKO) mice and cultured VSMCs infected with Lv-shMYPT1 to explore phenotypic switching of VSMCs and the accompanied impacts on BBB integrity. We found that MYPT1 deficiency induced phenotypic switching of synthetic VSMCs, which aggravated BBB disruption. Proteomic analysis identified evolutionarily conserved signaling intermediates in Toll pathways (ECSIT) as a downstream molecule that promotes activation of synthetic VSMCs and contributed to IL-6 expression. Knocking down ECSIT rescued phenotypic switching of VSMCs and BBB disruption. Additionally, inhibition of IL-6 decreased BBB permeability. These findings reveal that MYPT1 deficiency activated phenotypic switching of synthetic VSMCs and induced BBB disruption through ECSIT-IL-6 signaling after ischemic stroke.

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MYPT1 deficiency induces activation of synthetic VSMCs and aggravates BBB disruption

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Synthetic VSMCs release more IL-6 to destroy BBB in a contact-independent way

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MYPT1-ECSIT-IL-6 signaling pathway regulates synthetic VSMC-mediated BBB disruption

The CD200/CD200R mechanism in mesenchymal stem cells' regulation of dendritic cells

OBJECTIVE

To investigate the CD200/CD200R pathway mechanism in mesenchymal stem cells' (MSC) regulation of dendritic cells (DC) (MSc).

METHODS

We collected marrow samples from 40 patients admitted to our hospital from January 2018 to December 2019. The bone marrow MSCs were cultivated, and the peripheral blood mononuclear cells (PBMC) and peripheral blood DC were isolated to establish an in vitro immune response model. The expressions of the CD200 molecule on the surface of MSC were measured. Anti-CD200 blocking antibodies were added to the culture system to observe the effect of the PBMC differentiation and the immature DC (imDC) to mature DC (mDC). Then the impact of the different positive rates of CD200 in the same MSC on imDC maturity was measured.

RESULTS

After adding mitogen pHA, the IL-4, IL-10, and TNF-α secretions were increased (all P<0.05), and the OD value of the PBMC+pHA group was higher than it was in the PBMC group. After stimulated by pHA, the CD200 of the MSC group was higher than it was in the MSC+PBMC group (P<0.05). The MSC+PBMC group co-culture inhibited the development of imDC to mDC. Adding anti-CD200 antibodies to the MSC+PBMC co-culture system, MSC could still inhibit the differentiation of PBMC to imDC, and MSC had a significant inhibition effect on imDC to mDC maturation (P=0.006). The addition of MSC reduces the maturation markers on the surface of mDC (P<0.05). The addition of MSC inhibited the ability of mDC to stimulate PBMC (P_OD<0.05) and decreased the IL-12 (P_IL-12<0.05) levels. The addition of the anti-CD200 antibody increased the proliferation ability of mDC to stimulate PBMC (P_OD<0.05), and it also increased the IL-12 levels in mDC (P_IL-12<0.05). The expression of the DC mature immune phenotype in the CD200 high expression group was weak (P_{CD83, CD86}<0.05).

CONCLUSION

The mechanism by which MSC inhibits DC may be achieved through the CD200/CD200R pathway, and the CD200/CD200R pathway mainly acts on the process from imDC to mDC.

Quantitative proteomics revealed extensive microenvironmental changes after stem cell transplantation in ischemic stroke

The local microenvironment is essential to stem cell-based therapy for ischemic stroke, and spatiotemporal changes of the microenvironment in the pathological process provide vital clues for understanding the therapeutic mechanisms. However, relevant studies on microenvironmental changes were mainly confined in the acute phase of stroke, and long-term changes remain unclear. This study aimed to investigate the microenvironmental changes in the subacute and chronic phases of ischemic stroke after stem cell transplantation. Herein, induced pluripotent stem cells (iPSCs) and neural stem cells (NSCs) were transplanted into the ischemic brain established by middle cerebral artery occlusion surgery. Positron emission tomography imaging and neurological tests were applied to evaluate the metabolic and neurofunctional alterations of rats transplanted with stem cells. Quantitative proteomics was employed to investigate the protein expression profiles in iPSCs-transplanted brain in the subacute and chronic phases of stroke. Compared with NSCs-transplanted rats, significantly increased glucose metabolism and neurofunctional scores were observed in iPSCs-transplanted rats. Subsequent proteomic data of iPSCs-transplanted rats identified a total of 39 differentially expressed proteins in the subacute and chronic phases, which are involved in various ischemic stroke-related biological processes, including neuronal survival, axonal remodeling, antioxidative stress, and mitochondrial function restoration. Taken together, our study indicated that iPSCs have a positive therapeutic effect in ischemic stroke and emphasized the wide-ranging microenvironmental changes in the subacute and chronic phases.

Intracerebral Transplantation of Neural Stem Cells Restores Manganese-Induced Cognitive Deficits in Mice

Manganese (Mn) is a potent neurotoxin known to cause long-lasting structural damage and progressive cognitive deficits in the brain. However, new therapeutic approaches are urgently needed since current treatments only target symptoms of Mn exposure. Recent studies have suggested a potential role for multipotent neural stem cells (NSCs) in the etiology of Mn-induced cognitive deficits. In this study, we evaluated the effect of direct intracerebral transplantation of NSCs on cognitive function of mice chronically exposed to MnCl₂, and further explored the distribution of transplanted NSCs in brain tissues. NSCs were isolated and bilaterally injected into the hippocampal regions or lateral ventricles of Mn-exposed mice. The results showed that many transplanted cells migrated far away from the injection sites and survived in vivo in the Mn-exposed mouse brain, implying enhanced neurogenesis in the host brain. We found that NSCs transplanted into either the hippocampal regions or the lateral ventricles significantly improved spatial learning and memory function of the Mn-exposed mice in the Morris water maze. Immunofluorescence analyses indicated that some surviving NSCs differentiated into neurons or glial cells, which may have become functionally integrated into the impaired local circuits, providing a possible cellular basis for the improvement of cognitive function in NSC-transplanted mice. Taken together, our findings confirm the Mn-induced impairment of neurogenesis in the brain and underscore the potential of treating Mn exposure by NSC transplantation, providing a practical therapeutic strategy against this type of neurotoxicity.

Competing endogenous RNA network analysis for screening inflammation‑related long non‑coding RNAs for acute ischemic stroke

Long non-coding RNAs (lncRNAs) represent potential biomarkers for the diagnosis and treatment of various diseases; however, the role of circulating acute ischemic stroke (AIS)-related lncRNAs remains relatively unknown. The present study aimed to screen crucial lncRNAs for AIS based on the competing endogenous RNA (ceRNA) hypothesis. The expression profile datasets for one mRNA, accession no. GSE16561, and four microRNAs (miRNAs), accession nos. GSE95204, GSE86291, GSE55937 and GSE110993, were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs), lncRNAs (DELs), and miRNAs (DEMs) were identified, and ClusterProfiler was used to interpret the function of the DEGs. Based on the protein-protein interaction (PPI) network and module analyses, hub DEGs were identified. A ceRNA network was established based on miRNA-mRNA or miRNA-lncRNA interaction pairs. In total, 2,041 DEGs and 5 DELs were identified between the AIS and controls samples in GSE16561, and 10 DEMs between at least two of the four miRNA expression profiles. A PPI network was constructed with 1,235 DEGs, among which 20 genes were suggested to be hub genes. The hub genes paxillin (PXN), FYN-proto-oncogene, Src family tyrosine kinase (FYN), ras homolog family member A (RHOA), STAT1, and growth factor receptor-bound protein 2 (GRB2), were amongst the most significantly enriched modules extracted from the PPI network. Functional analysis revealed that these hub genes were associated with inflammation-related signaling pathways. An AIS-related ceRNA network was constructed, in which 4 DELs were predicted to function as ceRNAs for 9 DEMs, to regulate the five identified hub genes; that is, minichromosome maintenance complex component 3 associated protein-antisense RNA 1 (MCM3AP-AS1)/long intergenic non-protein coding RNA 1089 (LINC01089)/hsa-miRNA (miR)-125a/FYN, inositol-tetrakisphosphate 1-kinase-antisense RNA 1 (ITPK1-AS1)/hsa-let-7i/RHOA/GRB2/STAT1, and human leukocyte antigen complex group 27 (HCG27)/hsa-miR-19a/PXN interaction axes. In conclusion, MCM3AP-AS1, LINC01089, ITPK1-AS1, and HCG27 may represent new biomarkers and underlying targets for the treatment of AIS.

Umbilical cord stem cells: Background, processing and applications

Stem cells have currently gained attention in the field of medicine not only due to their ability to repair dysfunctional or damaged cells, but also they could be used as drug delivery system after being engineered to do so. Human umbilical cord is attractive source for autologous and allogenic stem cells that are currently amenable to treatment of various diseases. Human umbilical cord stem cells are -in contrast to embryonic and fetal stem cells- ethically noncontroversial, inexpensive and readily available source of cells. Umbilical cord, umbilical cord vein, amnion/placenta and Wharton's jelly are all rich of many types of multipotent stem cell populations capable of forming many different cell types. This review will focus on umbilical cord stem cells processing and current application in medicine.

Oligodendrocyte precursor cells transplantation protects blood-brain barrier in a mouse model of brain ischemia via Wnt/β-catenin signaling

Blood–brain barrier damage is a critical pathological feature of ischemic stroke. Oligodendrocyte precursor cells are involved in maintaining blood–brain barrier integrity during the development. However, whether oligodendrocyte precursor cell could sustain blood–brain barrier permeability during ischemic brain injury is unknown. Here, we investigate whether oligodendrocyte precursor cell transplantation protects blood–brain barrier integrity and promotes ischemic stroke recovery. Adult male ICR mice (n = 68) underwent 90 min transient middle cerebral artery occlusion. After ischemic assault, these mice received stereotactic injection of oligodendrocyte precursor cells (6 × 10⁵). Oligodendrocyte precursor cells transplantation alleviated edema and infarct volume, and promoted neurological recovery after ischemic stroke. Oligodendrocyte precursor cells reduced blood–brain barrier leakage via increasing claudin-5, occludin and β-catenin expression. Administration of β-catenin inhibitor blocked the beneficial effects of oligodendrocyte precursor cells. Wnt7a protein treatment increased β-catenin and claudin-5 expression in endothelial cells after oxygen–glucose deprivation, which was similar to the results of the conditioned medium treatment of oligodendrocyte precursor cells on endothelial cells. We demonstrated that oligodendrocyte precursor cells transplantation protected blood–brain barrier in the acute phase of ischemic stroke via activating Wnt/β-catenin pathway. Our results indicated that oligodendrocyte precursor cells transplantation was a novel approach to the ischemic stroke therapy.

Why not Intravenous Thrombolysis in Patients with Recurrent Stroke within 3 Months?

Acute ischemic stroke continues to be a very severe disorder that has significant impact on human health. Its treatment options are limited and alteplase remains the only American Food and Drug Administration-approved drug for patients with acute ischemic stroke. Furthermore, intravenous thrombolysis remains substantially underutilized, because it has rigorous indications and contraindications. Most patients simply do not meet these criteria and cannot receive thrombolytic treatment. Guidelines in many countries currently include a history of stroke within months as one of the exclusion criteria for intravenous thrombolysis. Although this is based on previous data, it lacks strong evidentiary support. Several recent studies suggested that intravenous thrombolysis may be beneficial for this patient population. We reviewed relevant publications of intravenous thrombolysis or repeated intravenous thrombolysis in patients with a history of stroke in the past 3 months. We found that intravenous thrombolysis in these patients is not as hazardous as previously believed. Among patients with relatively small infarctions and a good prognosis, intravenous thrombolysis may be a good treatment option. We hope that more research will be carried out on this topic to reexamine the criteria for intravenous thrombolysis to allow more patients to benefit from treatment.

Proteomic Analysis of a Rat Cerebral Ischemic Injury Model after Human Cerebral Endothelial Cell Transplantation

Objective

Cerebral endothelial cells have unique biological features and are fascinating candidate cells for stroke therapy.

Methods

In order to understand the molecular mechanisms of human cerebral endothelial cell (hCMEC/D3) transplantation in a rat stroke model, we performed proteomic analysis using 2-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Protein expression was confirmed by quantitative real-time PCR and Western blot.

Results

Several protein spots were identified by gel electrophoresis in the sham, cerebral ischemia (CI), and CI with hCMEC/D3 treatment cerebral ischemia with cell transplantation (CT) groups, and we identified 14 differentially expressed proteins in the CT group. Proteins involved in mitochondrial dysfunction (paraplegin matrix AAA peptidase subunit, SPG7), neuroinflammation (peroxiredoxin 6, PRDX6), and neuronal death (zinc finger protein 90, ZFP90) were markedly reduced in the CT group compared with the CI group. The expression of chloride intracellular channel 4 proteins involved in post-ischemic vasculogenesis was significantly decreased in the CI group but comparable to sham in the CT group.

Conclusion

These results contribute to our understanding of the early phase processes that follow cerebral endothelial cell treatment in CI. Moreover, some of the identified proteins may present promising new targets for stroke therapy.