Synthetic VSMCs induce BBB disruption mediated by MYPT1 in ischemic stroke

MYPT1SMKO Mice Function as a Novel Spontaneous Age- and Hypertension-Dependent Animal Model of CSVD

Cerebral small vessel disease (CSVD) is the most common progressive vascular disease that causes vascular dementia. Aging and hypertension are major contributors to CSVD, but the pathophysiological mechanism remains unclear, mainly due to the lack of an ideal animal model. Our previous study revealed that vascular smooth muscle cell (VSMC)-specific myosin phosphatase target subunit 1 (MYPT1) knockout (MYPT1SMKO) leads to constant hypertension, prompting us to explore whether hypertensive MYPT1SMKO mice can be considered a novel CSVD animal model. Here, we found that MYPT1SMKO mice displayed age-dependent CSVD-like neurobehaviors, including decreased motion speed, anxiety, and cognitive decline. MYPT1SMKO mice exhibited remarkable white matter injury compared with control mice, as shown by the more prominent loss of myelin at 12 months of age. Additionally, MYPT1SMKO mice were found to exhibit CSVD-like small vessel impairment, including intravascular hyalinization, perivascular space enlargement, and microbleed and blood-brain barrier (BBB) disruption. Last, our results revealed that the brain of MYPT1SMKO mice was characterized by an exacerbated inflammatory microenvironment, which is similar to patients with CSVD. In light of the above structural and functional phenotypes that closely mimic the conditions of human CSVD, we suggest that MYPT1SMKO mice are a novel age- and hypertension-dependent animal model of CSVD.

FGF17 protects cerebral ischemia reperfusion-induced blood-brain barrier disruption via FGF receptor 3-mediated PI3K/AKT signaling pathway

Maintaining blood-brain barrier (BBB) integrity is critical components of therapeutic approach for ischemic stroke. Fibroblast growth factor 17 (FGF17), a member of FGF8 superfamily, exhibits the strongest expression throughout the wall of all major arteries during development. However, its molecular action and potential protective role on brain endothelial cells after stroke remains unclear. Here, we observed reduced levels of FGF17 in the serum of patients with ischemic stroke, as well as in the brains of mice subjected to middle cerebral artery occlusion (MCAO) injury and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced brain microvascular endothelial cells (bEnd.3) cells. Moreover, treatment with exogenous recombinant human FGF17 (rhFGF17) decreased infarct volume, improved neurological deficits, reduced Evans Blue leakage and upregulated the expression of tight junctions in MCAO-injured mice. Meanwhile, rhFGF17 increased cell viability, enhanced trans-endothelial electrical resistance, reduced sodium fluorescein leakage, and alleviated reactive oxygen species (ROS) generation in OGD/R-induced bEnd.3 cells. Mechanistically, the treatment with rhFGF17 resulted in nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation and upregulation of heme oxygenase-1 (HO-1) expression. Additionally, based on in-vivo and in-vitro research, rhFGF17 exerted protective effects against ischemia/reperfusion (I/R) -induced BBB disruption and endothelial cell apoptosis through the activation of the FGF receptor 3/PI3K/AKT signaling pathway. Overall, our findings indicated that FGF17 may hold promise as a novel therapeutic strategy for ischemic stroke patients.

The Role of NRF2 in Cerebrovascular Protection: Implications for Vascular Cognitive Impairment and Dementia (VCID)

Vascular cognitive impairment and dementia (VCID) represents a broad spectrum of cognitive decline secondary to cerebral vascular aging and injury. It is the second most common type of dementia, and the prevalence continues to increase. Nuclear factor erythroid 2-related factor 2 (NRF2) is enriched in the cerebral vasculature and has diverse roles in metabolic balance, mitochondrial stabilization, redox balance, and anti-inflammation. In this review, we first briefly introduce cerebrovascular aging in VCID and the NRF2 pathway. We then extensively discuss the effects of NRF2 activation in cerebrovascular components such as endothelial cells, vascular smooth muscle cells, pericytes, and perivascular macrophages. Finally, we summarize the clinical potential of NRF2 activators in VCID.

IGF1R deficiency in vascular smooth muscle cells impairs myogenic autoregulation and cognition in mice

Introduction

Cerebrovascular pathologies contribute to cognitive decline during aging, leading to vascular cognitive impairment and dementia (VCID). Levels of circulating insulin-like growth factor 1 (IGF-1), a vasoprotective hormone, decrease during aging. Decreased circulating IGF-1 in animal models leads to the development of VCID-like symptoms, but the cellular mechanisms underlying IGF-1-deficiency associated pathologies in the aged cerebrovasculature remain poorly understood. Here, we test the hypothesis that vascular smooth muscle cells (VSMCs) play an integral part in mediating the vasoprotective effects of IGF-1.

Methods

We used a hypertension-based model of cerebrovascular dysfunction in mice with VSMC-specific IGF-1 receptor (Igf1r) deficiency and evaluated the development of cerebrovascular pathologies and cognitive dysfunction.

Results

VSMC-specific Igf1r deficiency led to impaired cerebral myogenic autoregulation, independent of blood pressure changes, which was also associated with impaired spatial learning and memory function as measured by radial arm water maze and impaired motor learning measured by rotarod. In contrast, VSMC-specific IGF-1 receptor knockdown did not lead to cerebral microvascular rarefaction.

Discussion

These studies suggest that VSMCs are key targets for IGF-1 in the context of cerebrovascular health, playing a role in vessel stability alongside other cells in the neurovascular unit, and that VSMC dysfunction in aging likely contributes to VCID.

Linarin ameliorates ischemia-reperfusion injury by the inhibition of endoplasmic reticulum stress targeting AKR1B1

Due to various factors, there is still a lack of effective neuroprotective agents for ischemic stroke in clinical practice. Neuroinflammation and neuronal apoptosis mediated by endoplasmic reticulum stress are some of the important pathological mechanisms in ischemic stroke. Linarin has been reported to have anti-inflammation, antioxidant, and anti-apoptotic effects in myocardial ischemia, osteoarthritis, and kidney disease. Whether it exerts neuroprotective functions in ischemic stroke has not been investigated. The results showed that linarin could reduce the infarct volume in cerebral ischemia animal models, improve the neurological function scores and suppress the expression of inflammatory factors mediating the NF-κB. Meanwhile, it could protect the neurons from OGD/R-induced-apoptosis, which was related to the PERK-eIF2α pathway. Our results suggested linarin could inhibit neuronal inflammation and apoptosis induced by endoplasmic reticulum stress. Furthermore, the neuroprotective effect of linarin may be related to the inhibition of AKR1B1. Our study offers new insight into protecting against ischemia-reperfusion injury by linarin treatment in stroke.

Microvascular smooth muscle cells exhibit divergent phenotypic switching responses to platelet-derived growth factor and insulin-like growth factor 1

OBJECTIVE

Vascular smooth muscle cell (VSMC) phenotypic switching is critical for normal vessel formation, vascular stability, and healthy brain aging. Phenotypic switching is regulated by mediators including platelet derived growth factor (PDGF)-BB, insulin-like growth factor (IGF-1), as well as transforming growth factor-β (TGF-β) and endothelin-1 (ET-1), but much about the role of these factors in microvascular VSMCs remains unclear.

METHODS

We used primary rat microvascular VSMCs to explore PDGF-BB- and IGF-1-induced phenotypic switching.

RESULTS

PDGF-BB induced an early proliferative response, followed by formation of polarized leader cells and rapid, directionally coordinated migration. In contrast, IGF-1 induced cell hypertrophy, and only a small degree of migration by unpolarized cells. TGF-β and ET-1 selectively inhibit PDGF-BB-induced VSMC migration primarily by repressing migratory polarization and formation of leader cells. Contractile genes were downregulated by both growth factors, while other genes were differentially regulated by PDGF-BB and IGF-1.

CONCLUSIONS

These studies indicate that PDGF-BB and IGF-1 stimulate different types of microvascular VSMC phenotypic switching characterized by different modes of cell migration. Our studies are consistent with a chronic vasoprotective role for IGF-1 in VSMCs in the microvasculature while PDGF is more involved in VSMC proliferation and migration in response to acute activities such as neovascularization. Better understanding of the nuances of the phenotypic switching induced by these growth factors is important for our understanding of a variety of microvascular diseases.

Proteomic advance of ischemic stroke: preclinical, clinical, and intervention

Ischemic stroke (IS) is the most common type of stroke and is characterized by high rates of mortality and long-term injury. The prediction and early diagnosis of IS are therefore crucial for optimal clinical intervention. Proteomics has provided important techniques for exploring protein markers associated with IS, but there has been no systematic evaluation and review of research that has used these techniques. Here, we review the differential proteins that have been found in cell- and animal- based studies and clinical trials of IS in the past 10 years; determine the key pathological proteins that have been identified in clinical trials; summarize the target proteins affected by interventions aimed at treating IS, with a focus on traditional Chinese medicine treatments. Overall, we clarify findings and problems that have been identified in recent proteomics research on IS and provide suggestions for improvements in this area. We also suggest areas that could be explored for determining the pathogenesis and developing interventions for IS.

Identification of novel key markers that are induced during traumatic brain injury in mice

Background

Traumatic brain injury (TBI) has emerged as an increasing public health problem but has not been well studied, particularly the mechanisms of brain cellular behaviors during TBI.

Methods

In this study, we established an ischemia/reperfusion (I/R) brain injury mice model using transient middle cerebral artery occlusion (tMCAO) strategy. After then, RNA-sequencing of frontal lobes was performed to screen key inducers during TBI. To further verify the selected genes, we collected peripheral blood mononuclear cells (PBMCs) from TBI patients within 24 h who attended intensive care unit (ICU) in the Affiliated Hospital of Yangzhou University and analyzed the genes expression using RT-qPCR. Finally, the receiver operator characteristic (ROC) curves and co-expression with cellular senescence markers were applied to evaluate the predictive value of the genes.

Results

A total of six genes were screened out from the RNA-sequencing based on their novelty in TBI and implications in apoptosis and cellular senescence signaling. RT-qPCR analysis of PBMCs from patients showed the six genes were all up-regulated during TBI after comparing with healthy volunteers who attended the hospital for physical examination. The area under ROC (AUC) curves were all >0.7, and the co-expression scores of the six genes with senescence markers were all significantly positive. We thus identified TGM1, TGM2, ATF3, RCN3, ORAI1 and ITPR3 as novel key markers that are induced during TBI, and these markers may also serve as potential predictors for the progression of TBI.

MicroRNA-361-5p acts as a biomarker for carotid artery stenosis and promotes vascular smooth muscle cell proliferation and migration

BACKGROUND

Vascular smooth muscle cells (VSMCs) dysfunction participates in carotid artery stenosis (CAS). The study aimed to examine the expression pattern of miR-361-5p in CAS patients, and explore its role in VSMCs proliferation and migration.

METHODS

qRT-PCR was performed for the detection of miR-361-5p in serum samples of 150 CAS cases and 150 healthy people. Multiple logistic regression analysis and receiver operating characteristic (ROC) curve was accomplished to detect diagnostic value via SPSS 21.0 statistical software. Cell function of VSMCs was evaluated. Target association was predicted through bioinformatic analysis and confirmed via luciferase activity.

RESULTS

Serum miR-361-5p was enhanced in CAS cases and was positively correlated with CAS degree. Logistic regression analysis determined the independent influence of miR-361-5p in CAS, and ROC curve demonstrated its diagnostic value with AUC of 0.892. miR-361-5p promoted VSMCs proliferation and migration, but the influence was counteracted by TIMP4.

CONCLUSIONS

MiR-361-5p is a promising biomarker for CAS, and can be used as a potential target for early diagnosis and treatment of CAS. MiR-361-5p can promote VSMCs proliferation and migration via targeting TIMP4.

Vascular smooth muscle cell dysfunction in neurodegeneration

Vascular smooth muscle cells (VSMCs) are the key moderators of cerebrovascular dynamics in response to the brain's oxygen and nutrient demands. Crucially, VSMCs may provide a sensitive biomarker for neurodegenerative pathologies where vasculature is compromised. An increasing body of research suggests that VSMCs have remarkable plasticity and their pathophysiology may play a key role in the complex process of neurodegeneration. Furthermore, extrinsic risk factors, including environmental conditions and traumatic events can impact vascular function through changes in VSMC morphology. VSMC dysfunction can be characterised at the molecular level both preclinically, and clinically ex vivo. However the identification of VSMC dysfunction in living individuals is important to understand changes in vascular function at the onset and progression of neurological disorders such as dementia, Alzheimer's disease, and Parkinson's disease. A promising technique to identify changes in the state of cerebral smooth muscle is cerebrovascular reactivity (CVR) which reflects the intrinsic dynamic response of blood vessels in the brain to vasoactive stimuli in order to modulate regional cerebral blood flow (CBF). In this work, we review the role of VSMCs in the most common neurodegenerative disorders and identify physiological systems that may contribute to VSMC dysfunction. The evidence collected here identifies VSMC dysfunction as a strong candidate for novel therapeutics to combat the development and progression of neurodegeneration, and highlights the need for more research on the role of VSMCs and cerebrovascular dynamics in healthy and diseased states.

A monoamine oxidase B inhibitor ethyl ferulate suppresses microglia-mediated neuroinflammation and alleviates ischemic brain injury

Microglia are the resident macrophages in the brain, which play a critical role in post-stroke neuroinflammation. Accordingly, targeting neuroinflammation could be a promising strategy to improve ischemic stroke outcomes. Ethyl ferulate (EF) has been confirmed to possess anti-inflammatory properties in several disease models, including acute lung injury, retinal damage and diabetes-associated renal injury. However, the effects of EF on microglial activation and the resolution of post-stroke neuroinflammation remains unknown. Here, we found that EF suppressed pro-inflammatory response triggered by lipopolysaccharide (LPS) stimulation in primary microglia and BV2 cell lines, as well as post-stroke neuroinflammation in an in vivo transient middle cerebral artery occlusion (tMCAO) stroke model in C57BL/6 mice, consequently ameliorating ischemic brain injury. Furthermore, EF could directly bind and inhibit the activity of monoamine oxidase B (MAO-B) to reduce pro-inflammatory response. Taken together, our study identified a MAO-B inhibitor, Ethyl ferulate, as an active compound with promising potentials for suppressing post-stroke neuroinflammation.

Regulation of Microglia-Activation-Mediated Neuroinflammation to Ameliorate Ischemia-Reperfusion Injury via the STAT5-NF-κB Pathway in Ischemic Stroke

Inflammatory reaction after ischemia-reperfusion contributes significantly to a worsened prognosis, and microglia activation is the main resource of inflammation in the nervous system. Targeting STAT5 has been shown to be a highly effective anti-inflammatory therapy; however, the mechanism by which the STAT5 signaling pathway regulates neuroinflammation following brain injury induced by ischemia-reperfusion remains unclear. Dauricine is an effective agent in anti-inflammation and neuroprotection, but the mechanism by which dauricine acts in ischemia-reperfusion remained unknown. This study is the first to find that the anti-inflammation mechanism of dauricine mainly occurs through the STAT5-NF-κB pathway and that it might act as a STAT5 inhibitor. Dauricine suppresses the inflammation caused by cytokines Eotaxin, KC, TNF-α, IL-1α, IL-1β, IL-6, IL-12β, and IL-17α, as well as inhibiting microglia activation. The STAT5b mutant at Tyr-699 reverses the protective effect of dauricine on the oxygen-glucose deprivation-reperfusion injury of neurons and reactivates the P-NF-κB expression in microglia. These results suggest that dauricine might be able to suppress the neuroinflammation and protect the neurons from the injury of post-ischemia-reperfusion injury via mediating the microglia activation through the STAT5-NF-κB pathway. As a potential therapeutic target for neuroinflammation, STAT5 needs to be given further attention regarding its role in ischemic stroke.

Serpine1 Regulates Peripheral Neutrophil Recruitment and Acts as Potential Target in Ischemic Stroke

Introduction

Peripheral neutrophil infiltration can exacerbate ischemia–reperfusion injury. We focused on the relationship between various peripheral immune cells and cerebral ischemia–reperfusion (I/R) injury.

Methods

In this study, we investigated the effects of dauricine on neuronal injury induced by ischemia–reperfusion and peripheral immune cells after ischemic stroke in mouse model, and we explored the undefined mechanisms of regulating peripheral immune cells through RNA sequencing and various biochemical verification in vitro and in vivo.

Results

We found that dauricine improved the neurological deficits of I/R injury, reduced the infarct volume, and improved the neurological scores. Furthermore, dauricine reduced the infiltration of neutrophils into the brain after MCAO-R and increased peripheral neutrophils but unchanged the permeability of the endotheliocyte Transwell system in an in vitro blood-brain barrier (BBB) model. RNA sequencing showed that chemotaxis factors, such as CXCL3, CXCL11, CCL20, CCL22, IL12a, IL23a, and serpine1, might play a crucial role. Overexpression of serpine1 reversed LPS-induced migration of neutrophils. Dauricine can directly bind with serpine1 in ligand–receptor docking performed with the Autodock and analyzed with PyMOL.

Conclusion

We identified chemotaxis factor serpine1 played a crucial role in peripheral neutrophil infiltration, which may contribute to reduce the neuronal injury induced by ischemia–reperfusion. These findings reveal that serpine1 may act as a potential treatment target in the acute stage of ischemic stroke.