Transcriptomics of post-stroke angiogenesis in the aged brain

Enriched environment enhances angiogenesis in ischemic stroke through SDF-1/CXCR4/AKT/mTOR pathway

Environmental-gene interactions significantly influence various bodily functions. Enriched environment (EE), a non-pharmacological treatment method, enhances angiogenesis in ischemic stroke (IS). However, underlying the role of EE in angiogenesis in aged mice post-IS remain unclear. This study aimed to determine the potential mechanism by which EE mediates angiogenesis in 12-month-old IS mice and oxygen-glucose deprivation/reperfusion (OGD/R)-induced bEnd.3 cells. In vivo, EE treatment alleviated the neurological deficits, enhanced angiogenesis, upregulated SDF-1, VEGFA, and the AKT/mTOR pathway. In addition, exogenous SDF-1 treatment had a protective effect similar to that of EE treatment in aged mice with IS. However, SDF-1 neutralizing antibody, AMD3100 (CXCR4 inhibitor), ARQ092 (AKT inhibitor), and rapamycin (mTOR inhibitor) treatment blocked the neuroprotective effect of EE treatment and inhibited angiogenesis in IS mice. In vitro, exogenous SDF-1 promoted migration of OGD/R-induced bEnd.3 cells and activated the AKT/mTOR pathway. AMD3100, ARQ092, and rapamycin inhibited SDF-1-induced cell migration. Collectively, these findings demonstrate that EE enhances angiogenesis and improves the IS outcomes through SDF-1/CXCR4/AKT/mTOR pathway.

Extracellular Vesicles Obtained from Hypoxic Mesenchymal Stromal Cells Induce Neurological Recovery, Anti-inflammation, and Brain Remodeling After Distal Middle Cerebral Artery Occlusion in Rats

Small extracellular vesicles (sEVs) obtained from mesenchymal stromal cells (MSCs) have shown considerable promise as restorative stroke treatment. In a head-to-head comparison in mice exposed to transient proximal middle cerebral artery occlusion (MCAO), sEVs obtained from MSCs cultured under hypoxic conditions particularly potently enhanced long-term brain tissue survival, microvascular integrity, and angiogenesis. These observations suggest that hypoxic preconditioning might represent the strategy of choice for harvesting MSC-sEVs for clinical stroke trials. To test the efficacy of hypoxic MSCs in a second stroke model in an additional species, we now exposed 6-8-month-old Sprague-Dawley rats to permanent distal MCAO and intravenously administered vehicle, platelet sEVs, or sEVs obtained from hypoxic MSCs (1% O2; 2 × 106 or 2 × 107 cell equivalents/kg) at 24 h, 3, 7, and 14 days post-MCAO. Over 28 days, motor-coordination recovery was evaluated by rotating pole and cylinder tests. Ischemic injury, brain inflammatory responses, and peri-infarct angiogenesis were assessed by infarct volumetry and immunohistochemistry. sEVs obtained from hypoxic MSCs did not influence infarct volume in this permanent MCAO model, but promoted motor-coordination recovery over 28 days at both sEV doses. Ischemic injury was associated with brain ED1+ macrophage infiltrates and Iba1+ microglia accumulation in the peri-infarct cortex of vehicle-treated rats. Hypoxic MSC-sEVs reduced brain macrophage infiltrates and microglia accumulation in the peri-infarct cortex. In vehicle-treated rats, CD31+/BrdU+ proliferating endothelial cells were found in the peri-infarct cortex. Hypoxic MSC-sEVs increased the number of CD31+/BrdU+ proliferating endothelial cells. Our results provide evidence that hypoxic MSC-derived sEVs potently enhance neurological recovery, reduce neuroinflammation. and increase angiogenesis in rat permanent distal MCAO.

Insulin-like growth factor-binding protein 7 (IGFBP7): A microenvironment-dependent regulator of angiogenesis and vascular remodeling

Insulin-like Growth Factor-Binding Protein 7 (IGFBP7) is an extracellular matrix (ECM) glycoprotein, highly enriched in activated vasculature during development, physiological and pathological tissue remodeling. Despite decades of research, its role in tissue (re-)vascularization is highly ambiguous, exhibiting pro- and anti-angiogenic properties in different tissue remodeling states. IGFBP7 has multiple binding partners, including structural ECM components, cytokines, chemokines, as well as several receptors. Based on current evidence, it is suggested that IGFBP7's bioactivity is strongly dependent on the microenvironment it is embedded in. Current studies indicate that during physiological angiogenesis, IGFBP7 promotes endothelial cell attachment, luminogenesis, vessel stabilization and maturation. Its effects on other stages of angiogenesis and vessel function remain to be determined. IGFBP7 also modulates the pro-angiogenic properties of other signaling factors, such as VEGF-A and IGF, and potentially acts as a growth factor reservoir, while its actual effects on the factors' signaling may depend on the environment IGFBP7 is embedded in. Besides (re-)vascularization, IGFBP7 clearly promotes progenitor and stem cell commitment and may exhibit anti-inflammatory and anti-fibrotic properties. Nonetheless, its role in inflammation, immunomodulation, fibrosis and cellular senescence is again likely to be context-dependent. Future studies are required to shed more light on the intricate functioning of IGFBP7.

Age-Related Alterations in Immune Function and Inflammation: Focus on Ischemic Stroke

The aging of the global population poses significant scientific challenges. Moreover, the biological process of aging is the most significant risk factor for most chronic illnesses; therefore, understanding the molecular and cellular mechanisms underlying these aging-related challenges is crucial for extending the healthy lifespan of older individuals. Preventing brain aging remains a priority public health goal, and integrative and comprehensive aging analyses have revealed that immunosenescence is a potential cause of age-related brain damage and disease (e.g., stroke). Importantly, the neuroinflammatory and immune systems present two-way contact and thus can affect each other. Emerging evidence supports the numerous effects of immunosenescence- and inflammation-mediated immunity in neurologically injured brains. In this study, we briefly outline how aging alters the pathophysiology and transcriptional amplitude in patients who experienced stroke and then discuss how the immune system and its cellular components and molecular mechanisms are affected by age after stroke. Finally, we highlight emerging interventions with the potential to slow down or reduce aging and prevent stroke onset.

Angiopoietin-Like Proteins: Cardiovascular Biology and Therapeutic Targeting for the Prevention of Cardiovascular Diseases

Despite the best pharmacologic tools available, cardiovascular diseases (CVDs) remain a major cause of morbidity and mortality in developed countries. After 2 decades of research, new therapeutic targets, such as angiopoietin-like proteins (ANGPTLs), are emerging. ANGPTLs belong to a family of 8 members, from ANGPTL1 to ANGPTL8; they have structural homology with angiopoietins and are secreted in the circulation. ANGPTLs display a multitude of physiological and pathologic functions; they contribute to inflammation, angiogenesis, cell death, senescence, hematopoiesis, and play a role in repair, maintenance, and tissue homeostasis. ANGPTLs-particularly the triad ANGPTL3, 4, and 8-have an established role in lipid metabolism through the regulation of triacylglycerol trafficking according to the nutritional status. Some ANGPTLs also contribute to glucose metabolism. Therefore, dysregulation in ANGPTL expression associated with abnormal circulating levels are linked to a plethora of CVD and metabolic disorders including atherosclerosis, heart diseases, diabetes, but also obesity and cancers. Because ANGPTLs bind to different receptors according to the cell type, antagonists are therapeutically inadequate. Recently, direct inhibitors of ANGPTLs, mainly ANGPTL3, have been developed, and specific monoclonal antibodies and antisense oligonucleotides are currently being tested in clinical trials. The aim of the current review is to provide an up-to-date preclinical and clinical overview on the function of the 8 members of the ANGPTL family in the cardiovascular system, their contribution to CVD, and the therapeutic potential of manipulating some of them.

Shared metabolic shifts in endothelial cells in stroke and Alzheimer's disease revealed by integrated analysis

Since metabolic dysregulation is a hallmark of both stroke and Alzheimer's disease (AD), mining shared metabolic patterns in these diseases will help to identify their possible pathogenic mechanisms and potential intervention targets. However, a systematic integration analysis of the metabolic networks of the these diseases is still lacking. In this study, we integrated single-cell RNA sequencing datasets of ischemic stroke (IS), hemorrhagic stroke (HS) and AD models to construct metabolic flux profiles at the single-cell level. We discovered that the three disorders cause shared metabolic shifts in endothelial cells. These altered metabolic modules were mainly enriched in the transporter-related pathways and were predicted to potentially lead to a decrease in metabolites such as pyruvate and fumarate. We further found that Lef1, Elk3 and Fosl1 may be upstream transcriptional regulators causing metabolic shifts and may be possible targets for interventions that halt the course of neurodegeneration.

Bystanders or not? Microglia and lymphocytes in aging and stroke

As the average age of the world population increases, more people will face debilitating aging-associated conditions, including dementia and stroke. Not only does the incidence of these conditions increase with age, but the recovery afterward is often worse in older patients. Researchers and health professionals must unveil and understand the factors behind age-associated diseases to develop a therapy for older patients. Aging causes profound changes in the immune system including the activation of microglia in the brain. Activated microglia promote T lymphocyte transmigration leading to an increase in neuroinflammation, white matter damage, and cognitive impairment in both older humans and rodents. The presence of T and B lymphocytes is observed in the aged brain and correlates with worse stroke outcomes. Preclinical strategies in stroke target either microglia or the lymphocytes or the communications between them to promote functional recovery in aged subjects. In this review, we examine the role of the microglia and T and B lymphocytes in aging and how they contribute to cognitive impairment. Additionally, we provide an important update on the contribution of these cells and their interactions in preclinical aged stroke.

The Haematopoietically-expressed homeobox transcription factor: roles in development, physiology and disease

The Haematopoietically expressed homeobox transcription factor (Hhex) is a transcriptional repressor that is of fundamental importance across species, as evident by its evolutionary conservation spanning fish, amphibians, birds, mice and humans. Indeed, Hhex maintains its vital functions throughout the lifespan of the organism, beginning in the oocyte, through fundamental stages of embryogenesis in the foregut endoderm. The endodermal development driven by Hhex gives rise to endocrine organs such as the pancreas in a process which is likely linked to its role as a risk factor in diabetes and pancreatic disorders. Hhex is also required for the normal development of the bile duct and liver, the latter also importantly being the initial site of haematopoiesis. These haematopoietic origins are governed by Hhex, leading to its crucial later roles in definitive haematopoietic stem cell (HSC) self-renewal, lymphopoiesis and haematological malignancy. Hhex is also necessary for the developing forebrain and thyroid gland, with this reliance on Hhex evident in its role in endocrine disorders later in life including a potential role in Alzheimer's disease. Thus, the roles of Hhex in embryological development throughout evolution appear to be linked to its later roles in a variety of disease processes.

Integrated analysis of circRNA-associated ceRNA network in ischemic stroke

Introduction: Stroke, of which ischemic stroke (IS) is the major type, is the second leading cause of disability and death worldwide. Circular RNAs (circRNAs) are reported to play important role in the physiology and pathology of IS. CircRNAs often act as competing endogenous RNA (ceRNA) to regulate gene expression by acting as miRNA sponges. However, whole transcriptome-wide screenings of circRNA-mediated ceRNA networks associated with IS are still lacking. In the present study, we constructed a circRNA-miRNA-mRNA ceRNA network by whole transcriptome-wide analysis. Methods: CircRNAs, miRNAs and mRNAs expression profiles were downloaded from the Gene Expression Omnibus (GEO) datasets. We identified differentially expressed (DE) circRNAs, miRNAs, and mRNAs in IS patients. StarBase and CircBank databases were used to predict the miRNA targets of DEcircRNAs, and mirDIP database was used to predict the mRNA targets of DEmiRNAs. CircRNA-miRNA pairs and miRNA-mRNA pairs were established. Then, we identified hub genes via protein-protein interaction analysis and constructed a core ceRNA sub-network. Results: In total, 276 DEcircRNAs, 43 DEmiRNAs, and 1926 DEmRNAs were explored. The ceRNA network included 69 circRNAs, 24 miRNAs, and 92 mRNAs. The core ceRNA subnetwork included hsa_circ_0011474, hsa_circ_0023110, CDKN1A, FHL2, RPS2, CDK19, KAT6A, CBX1, BRD4, and ZFHX3. Discussion: In conclusion, we established a novel hsa_circ_0011474 - hsa-miR-20a-5p/hsa-miR-17-5p - CDKN1A ceRNA regulatory axis associated with IS. Our findings provide new insights into the pathogenesis of IS and offer promising diagnostic and predictive biomarkers.

TMT proteomics analysis of cerebrospinal fluid from patients with cerebral venous sinus thrombosis

CVST is a type of venous stroke that mainly affects young adults with no reliable diagnostic markers and effective treatment strategies for secondary pathologies. However, the underlying pathological molecular mechanisms remain unclear. Here, we systematically analyzed the molecule profiling of the cerebrospinal fluid (CSF) in CVST patients via tandem mass tag (TMT)-based proteomics for the first time, aiming to reveal the pathogenesis and provide evidence for the diagnosis and treatment of CVST. Five CVST patients and five control patients were selected, and CSF samples were analyzed by TMT proteomics. Differentially expressed proteins (DEPs) were acquired and bioinformatics analysis was performed. Besides, parallel reaction monitoring (PRM) was utilized to validate the DEPs. 468 differentially expressed proteins were screened, 185 of which were up-regulated and 283 were down-regulated (fold change >1.2, P < 0.05). Bioinformatics analysis displayed that these proteins were significantly enriched in multiple pathways related to a variety of pathophysiological processes. PRM verification showed that apolipoprotein E, MMP-2, neuroserpin, clusterin, and several other molecules were down-regulated. These identified proteins reveal unique pathophysiological characteristics secondary to CVST. Further characterization of these proteins in future research could enable their application as potential therapeutic targets and biomarkers in CVST therapy. SIGNIFICANCE: Cerebral venous sinus thrombosis (CVST) is an underrated and potentially fatal cause of stroke with a reported mortality of 5-10% worldwide. Currently, in addition to anticoagulant and thrombolytic therapy, effective treatments targeting the injured brain parenchyma after CVST remain limited. Besides, accurate diagnostic markers are still sorely lacking. In the present study, we will detect the alterations of the CSF protein spectrum of CVST patients by TMT technique, screen differentially expressed proteins, analyze the functions of these signals through bioinformatics methods, and finally validate the key molecules through parallel reaction monitoring (PRM) technique. Collectively, the study aimed to offer a reference for the discovery of specific protein/pathway alterations in the CSF of CVST patients and further reveal the underlying pathogenesis, thereby providing evidence for the diagnosis and treatment of CVST.

Microglial depletion exacerbates motor impairment and dopaminergic neuron loss in a 6-OHDA model of Parkinson's disease

6-hydroxydopamine (6-OHDA) is a common neurotoxin used to induce Parkinson's disease (PD) in mice, exerting neurotoxic effects through the production of reactive oxygen species and microglial activation. However, the role of microglia in PD is still not clear, with contradictory reports showing neuroprotection or exacerbation of neuronal death. Microglial depletion aggravates motor coordination impairments and reduces tyrosine hydroxylase positive neurons in the substantia nigra pars compacta. Moreover, MeCP2 and Adora1 genes expression were downregulated, suggesting they may be involved in the neurodegenerative process. This study highlights that microglia plays a protective role in dopaminergic neuron survival during the initial phase of PD, and the investigation of the mechanisms of this effect in future studies will help elucidate the pathophysiology of PD.

The age-dependent immune response to ischemic stroke

Stroke is a devastating cause of global morbidity and mortality. Ischemic brain injury triggers a profound local and systemic immune response that participates in stroke pathophysiology. In turn, this immune response has emerged as a potential therapeutic target. In order to maximize its therapeutic potential, it is critical to understand how the immune response to ischemic brain injury is affected by age - the strongest non-modifiable risk factor for stroke. The development of multi-omics and single-cell technologies has provided a more comprehensive characterization of transcriptional and cellular changes that occur during aging. In this review, we summarize recent advances in our understanding of how age-related immune alterations shape differential stroke outcomes in older versus younger organisms, highlighting studies in both experimental mouse models and patient cohorts. Wherever possible, we emphasize outstanding questions that present important avenues for future investigation with therapeutic value for the aging population.

3D printed multi-growth factor delivery patches fabricated using dual-crosslinked decellularized extracellular matrix-based hybrid inks to promote cerebral angiogenesis

Generally, brain angiogenesis is a tightly regulated process, which scarcely occurred in the absence of specific pathological conditions. Delivery of exogenous angiogenic factors enables the induction of desired angiogenesis by stimulating neovasculature formation. However, effective strategies of mimicking the angiogenesis process with exogenous factors have not yet been fully explored. Herein, we develop a 3D printed spatiotemporally compartmentalized cerebral angiogenesis inducing (SCAI) hydrogel patch, releasing dual angiogenic growth factors (GFs), using extracellular matrix-based hybrid inks. We introduce a new hybrid biomaterial-based ink for printing patches through dual crosslinking mechanisms: Chemical crosslinking with aza-Michael addition reaction with combining methacrylated hyaluronic acid (HAMA) and vascular-tissue-derived decellularized extracellular matrix (VdECM), and thermal crosslinking of VdECM. 3D printing technology, a useful approach with fabrication versatility with customizable systems and multiple biomaterials, is adopted to print three-layered hydrogel patch with spatially separated dual GFs as outer- and inner-layers that provide tunable release profiles of multiple GFs and fabrication versatility. Consequently, these layers of the patch spatiotemporally separated with dual GFs induce excellent neovascularization in the brain area, monitored by label-free photoacoustic microscopy in vivo. The developed multi-GFs releasing patch may offer a promising therapeutic approach of spatiotemporal drugs releasing such as cerebral ischemia, ischemic heart diseases, diabetes, and even use as vaccines. STATEMENT OF SIGNIFICANCE: Effective strategies of mimicking the angiogenesis process with exogenous factors have not yet been fully explored. In this study, we develop a 3D printed spatiotemporally compartmentalized cerebral angiogenesis inducing (SCAI) hydrogel patch, releasing dual angiogenic growth factors (GFs) using extracellular matrix-based hybrid inks. We introduce a new hybrid biomaterial-based ink through dual crosslinking mechanisms: Chemical crosslinking with aza-Michael addition, and thermal crosslinking. 3D printing technology is adopted to print three-layered hydrogel patch with spatially separated dual GFs as outer- and inner-layers that provide tunable release profiles of multiple GFs and fabrication versatility. Consequently, these layers of the patch spatiotemporally separated with dual GFs induce excellent neovascularization in the brain area, monitored by photoacoustic microscopy in vivo.

Sex-Mediated Differences in TNF Signaling- and ECM-Related Gene Expression in Aged Rat Kidney

Aging leads to the functional decline of an organism, which is associated with age and sex. To understand the functional change of kidneys depending on age and sex, we carried out a transcriptome analysis using RNA sequencing (RNA-Seq) data from rat kidneys. Four differentially expressed gene (DEG) sets were generated according to age and sex, and Gene Ontology analysis and overlapping analysis of Kyoto Encyclopedia of Genes and Genomes pathways were performed for the DEG sets. Through the analysis, we revealed that inflammation- and extracellular matrix (ECM)-related genes and pathways were upregulated in both males and females during aging, which was more prominent in old males than in old females. Furthermore, quantitative real-time PCR analysis confirmed that the expression of tumor necrosis factor (TNF) signaling-related genes, Birc3, Socs3, and Tnfrsf1b, and ECM-related genes, Cd44, Col3a1, and Col5a2, which showed that the genes were markedly upregulated in males and not females during aging. Also, hematoxylin-eosin (H&E) staining for histological analysis showed that renal damage was highly shown in old males rather than old females. In conclusion, in the rat kidney, the genes involved in TNF signaling and ECM accumulation are upregulated in males more than in females during aging. These results suggest that the upregulation of the genes may have a higher contribution to age-related kidney inflammation and fibrosis in males than in females.

General Characteristics and Promotion Properties of Circular PLOD2 in Patients with Glioma

BACKGROUND

Circular RNAs are closed endogenous RNAs that are involved in the progression of diverse tumors. Even with the most advanced combined treatments, patients with glioblastoma multiforme have a median survival time of <15 months. This study aimed to investigate the roles of circular PLOD2 (circPLOD2) in glioma tumorigenesis and tumor development and to clarify its tumor-promoting effects by bioinformatics analysis and molecular experiments.

METHODS

To determine the characteristics of circPLOD2 expression, quantitative real-time polymerase chain reaction was conducted. Stable knockdown of circPLOD2 was implemented for functional assays. Cell Counting Kit-8 and colony formation assays were used to measure cell proliferation. Transwell assays and tube formation assays were used to evaluate cell invasion and angiogenesis abilities, respectively. An intracranial xenograft model was established to determine the function of circPLOD2 in vivo. Further biochemical and Western blot analyses were conducted to evaluate proteins associated with circPLOD2.

RESULTS

circPLOD2 was upregulated in glioma tissues and cells. High expression of circPLOD2 was significantly associated with tumor size, World Health Organization grade, and molecular characteristics of glioma. circPLOD2 deregulation affected glioblastoma multiforme cell proliferation, invasion, and angiogenesis. Knockdown of circPLOD2 inhibited tumorigenesis in vivo. Further biochemical analysis showed that circPLOD2 was involved in oncogenic pathways and correlated with the expression of proteins related to proliferation, invasion, and angiogenesis.

CONCLUSIONS

Our data indicate that circPLOD2 promotes glioma tumorigenesis and tumor development in vitro and in vivo and that suppressing circPLOD2 could be a novel therapeutic strategy for glioma.

Neutrophil dynamics and inflammaging in acute ischemic stroke: A transcriptomic review

Stroke is among the leading causes of death and disability worldwide. Restoring blood flow through recanalization is currently the only acute treatment for cerebral ischemia. Unfortunately, many patients that achieve a complete recanalization fail to regain functional independence. Recent studies indicate that activation of peripheral immune cells, particularly neutrophils, may contribute to microcirculatory failure and futile recanalization. Stroke primarily affects the elderly population, and mortality after endovascular therapies is associated with advanced age. Previous analyses of differential gene expression across injury status and age identify ischemic stroke as a complex age-related disease. It also suggests robust interactions between stroke injury, aging, and inflammation on a cellular and molecular level. Understanding such interactions is crucial in developing effective protective treatments. The global stroke burden will continue to increase with a rapidly aging human population. Unfortunately, the mechanisms of age-dependent vulnerability are poorly defined. In this review, we will discuss how neutrophil-specific gene expression patterns may contribute to poor treatment responses in stroke patients. We will also discuss age-related transcriptional changes that may contribute to poor clinical outcomes and greater susceptibility to cerebrovascular diseases.

Data-Independent Acquisition-Based Serum Proteomic Profiling of Adult Moyamoya Disease Patients Reveals the Potential Pathogenesis of Vascular Changes

Moyamoya disease (MMD) is a chronic cerebrovascular disease with unknown etiology. The pathogenesis of vascular changes remains unclear. Ischemic and hemorrhagic adult MMD patients and healthy volunteers were enrolled to collect serum for data-independent acquisition (DIA)-based proteomic analysis and ELISA validation. DIA serum proteomic revealed that apolipoprotein C-I (APOC1), apolipoprotein D (APOD), and apolipoprotein A-IV (APOA4) were decreased. The reductases glutathione S-transferase omega-1 (GSTO1) and peptidyl-prolyl cis-trans isomerase A (PPIA) were upregulated, and ADAMTS-like protein 4 (ADAMTSL4) was downregulated in both ischemic and hemorrhagic MMD. Afamin (AFM) and transforming growth factor-beta-induced protein ig-h3 (TGFBI) increased in ischemic patients but decreased in hemorrhagic patients. Serum ELISA results confirmed that APOA4, APOC1, and APOD were decreased compared to controls. Then, we retrospectively analyzed biochemical indexes of 200 MMD patients. A total of 54 enrolled MMD patients showed decreased total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-c). APOA4, APOC1, and APOD were vital factors in the HDL decrease in MMD patients. Lipoprotein dysfunction in MMD patients is involved in MMD. Intimal thickening by enhanced adhesion, middle layer vascular smooth muscle cell migration, and decreased lipid antioxidant function represented by HDL are potential pathogeneses of vascular changes in MMD.

The Brain’s Microvascular Response to High Glycemia and to the Inhibition of Soluble Epoxide Hydrolase Is Sexually Dimorphic

Biological sex and a high glycemic diet (HGD) contribute to dementia, yet little is known about the operative molecular mechanisms. Our goal was to understand the differences between males and females in the multi-genomic response of the hippocampal microvasculature to the HGD, and whether there was vasculoprotection via the inhibition of soluble epoxide hydrolase (sEHI). Adult wild type mice fed high or low glycemic diets for 12 weeks, with or without an sEHI inhibitor (t-AUCB), had hippocampal microvessels isolated by laser-capture microdissection. Differential gene expression was determined by microarray and integrated multi-omic bioinformatic analyses. The HGD induced opposite effects in males and females: the HGD-upregulated genes were involved in neurodegeneration or neuroinflammation in males, whereas in females they downregulated the same pathways, favoring neuroprotection. In males, the HGD was associated with a greater number of clinical diseases than in females, the sEHI downregulated genes involved in neurodegenerative diseases to a greater extent with the HGD and compared to females. In females, the sEHI downregulated genes involved in endothelial cell functions to a greater extent with the LGD and compared to males. Our work has potentially important implications for sex-specific therapeutic targets for vascular dementia and cardiovascular diseases in males and females.

Conditioned Medium of Human Pluripotent Stem Cell-Derived Neural Precursor Cells Exerts Neurorestorative Effects against Ischemic Stroke Model

Previous studies have shown that early therapeutic events of neural precursor cells (NPCs) transplantation to animals with acute ischemic stroke readily protected neuronal cell damage and improved behavioral recovery through paracrine mechanisms. In this study, we tested the hypothesis that administration of conditioned medium from NPCs (NPC-CMs) could recapitulate the beneficial effects of cell transplantation. Rats with permanent middle cerebral artery occlusion (pMCAO) were randomly assigned to one of the following groups: PBS control, Vehicle (medium) controls, single (NPC-CM(S)) or multiple injections of NPC-CM(NPC-CM(M)) groups. A single intravenous injection of NPC-CM exhibited strong neuroregenerative potential to induce behavioral recovery, and multiple injections enhanced this activity further by suppressing inflammatory damage and inducing endogenous neurogenesis leading to histopathological and functional recovery. Proteome analysis of NPC-CM identified a number of proteins that are known to be associated with nervous system development, neurogenesis, and angiogenesis. In addition, transcriptome analysis revealed the importance of the inflammatory response during stroke recovery and some of the key hub genes in the interaction network were validated. Thus, our findings demonstrated that NPC-CM promoted functional recovery and reduced cerebral infarct and inflammation with enhanced endogenous neurogenesis, and the results highlighted the potency of NPC-CM in stroke therapy.

Alzheimer's Disease Connected Genes in the Post-Ischemic Hippocampus and Temporal Cortex

It is considered that brain ischemia can be causative connected to Alzheimer’s disease. In the CA1 and CA3 regions of the hippocampus and temporal cortex, genes related to Alzheimer’s disease, such as the amyloid protein precursor (APP), β-secretase (BACE1), presenilin 1 (PSEN1) and 2 (PSEN2), are deregulated by ischemia. The pattern of change in the CA1 area of the hippocampus covers all genes tested, and the changes occur at all post-ischemic times. In contrast, the pattern of gene changes in the CA3 subfield is much less intense, does not occur at all post-ischemic times, and is delayed in time post-ischemia relative to the CA1 field. Conversely, the pattern of gene alterations in the temporal cortex appears immediately after ischemia, and does not occur at all post-ischemic times and does not affect all genes. Evidence therefore suggests that various forms of dysregulation of the APP, BACE1 and PSEN1 and PSEN2 genes are associated with individual neuronal cell responses in the CA1 and CA3 areas of the hippocampus and temporal cortex with reversible cerebral ischemia. Scientific data indicate that an ischemic episode of the brain is a trigger of amyloidogenic processes. From the information provided, it appears that post-ischemic brain injury additionally activates neuronal death in the hippocampus and temporal cortex in an amyloid-dependent manner.

Potential Variables for Improved Reproducibility of Neuronal Cell Grafts at Stroke Sites

Interest is growing in using cell replacements to repair the damage caused by an ischemic stroke. Yet, the usefulness of cell transplants can be limited by the variability observed in their successful engraftment. For example, we recently showed that, although the inclusion of donor-derived vascular cells was necessary for the formation of large grafts (up to 15 mm3) at stroke sites in mice, the size of the grafts overall remained highly variable. Such variability can be due to differences in the cells used for transplantation or the host environment. Here, as possible factors affecting engraftment, we test host sex, host age, the extent of ischemic damage, time of transplant after ischemia, minor differences in donor cell maturity, and cell viability at the time of transplantation. We find that graft size at stroke sites correlates with the size of ischemic damage, host sex (females having graft sizes that correlate with damage), donor cell maturity, and host age, but not with the time of transplant after stroke. A general linear model revealed that graft size is best predicted by stroke severity combined with donor cell maturity. These findings can serve as a guide to improving the reproducibility of cell-based repair therapies.

Cerebroprotein hydrolysate injection is involved in promoting long-term angiogenesis, vessel diameter and density after cerebral ischemia in mice

AIMS

In this study, we aimed investigate the impacts of CH-I on angiogenesis, effects for vascular structure changes and long-term neurological recovery after ischemic stroke as well as the potential mechanisms.

MAIN METHODS

Young male mice subjected to intraluminal middle cerebral artery occlusion were administrated with CH-I once daily from day 1 to day 14 after stroke. The infarct volume was evaluated by TTC staining at day 7 after stroke. Neurological deficits were measured 1 to 28 days after stroke. Microvascular density, astrocyte coverage, and angiogenesis were assessed by IF, qRT-PCR, and WB at regular intervals after stroke. LSCI and TPMI measured changes in blood flow and vascular density and width from the day after stroke to day 28.

KEY FINDINGS

Compared with the dMCAO group, CH-I treatment significantly improved neurological recovery and reduced the infarct at day 7 after stroke. CH-I treatment increased the expression of the CD31, BrdU⁺/CD31⁺ microvessels and GFAP positive vessels in the peri-infarct cortex at day 7 to 28 after stroke. The expression of protein and gene were enhanced in CH-I group. CH-I significantly improved cerebral blood flow at day 7 after stroke. CH-I increased the vascular density and vascular width at day 14 after stroke.

SIGNIFICANCE

CH-I has been shown to restore nerve function, reduce the rate of cerebral infarction, increase microvascular density, and promote angiogenesis. CH-I improved cerebral blood flow, protected blood vessels from postoperative stenosis, and improved vascular plasticity.

Evaluation of anti-inflammatory diphenyldihaloketone EF24 in transient ischemic stroke model

OBJECTIVES

Revascularization is necessary in patients with ischemic stroke, however it does not address inflammation that contribute to reperfusion injury and the early growth of ischemic core. We investigated EF24, an anti-inflammatory agent, in a stroke model.

METHODS

Ischemic stroke was induced in mice by occluding middle cerebral artery for 1 h followed by reperfusion. EF24 was given either 10 min post-reperfusion (EF24_Post) or 10 min before occlusion (prophylactic, EF24_Pro). Survival, ipsilateral uptake of radioactive infarct marker ¹⁸F-fluoroglucaric acid (FGA), inflammatory cytokines, and tetrazolium chloride (TTC) staining were assessed.

RESULTS

Survival was increased in both EF24-treated groups compared to the stroke+vehicle group. Ipsilateral ¹⁸F-FGA uptake increased 2.6-fold in stroke+vehicle group compared to sham group (p < 0.05); the uptake in EF24-treated groups and sham group was not significantly different. TTC-staining also showed reduction in infarct size by EF24 treatment. Plasma IL-6, TNF-α, and corticosterone did not show significant changes among groups. However, ipsilateral tissue in stroke+vehicle mice showed increased IL-6 (>90-fold) and TNF-α (3-fold); the tissue IL-6 and TNF-α were significantly reduced in stroke+EF24_Pro and stroke+EF24_Post groups. ¹⁸F-FGA uptake significantly correlated with tissue IL-6 levels.

CONCLUSIONS

EF24 controls infarct growth and suppresses tissue inflammation in ischemic stroke, which can be monitored by ¹⁸F-FGA uptake.

Combination of Genomic and Transcriptomic Approaches Highlights Vascular and Circadian Clock Components in Multiple Sclerosis

Aiming at exploring vascular components in multiple sclerosis (MS) with brain outflow disturbance, we combined transcriptome analysis in MS internal jugular vein (IJV) wall with WES in MS families with vertical transmission of disease. Main results were the differential expression in IJV wall of 16 MS-GWAS genes and of seven genes (GRIN2A, GRIN2B, IL20RB, IL26, PER3, PITX2, and PPARGC1A) not previously indicated by GWAS but encoding for proteins functionally interacting with MS candidate gene products. Strikingly, 22/23 genes have been previously associated with vascular or neuronal traits/diseases, nine encoded for transcriptional factors/regulators and six (CAMK2G, GRIN2A, GRIN2B, N1RD1, PER3, PPARGC1A) for circadian entrainment/rhythm components. Among the WES low-frequency (MAF ≤ 0.04) SNPs (n = 7) filtered in the 16 genes, the NR1D1 rs17616365 showed significantly different MAF in the Network for Italian Genomes affected cohort than in the 1000 Genome Project Tuscany samples. This pattern was also detected in five nonintronic variants (GRIN2B rs1805482, PER3 rs2640909, PPARGC1A rs2970847, rs8192678, and rs3755863) in genes coding for functional partners. Overall, the study proposes specific markers and low-frequency variants that might help (i) to understand perturbed biological processes in vascular tissues contributing to MS disease, and (ii) to characterize MS susceptibility genes for functional association with disease-pathways.

Angptl2 is a Marker of Cellular Senescence: The Physiological and Pathophysiological Impact of Angptl2-Related Senescence

Cellular senescence is a cell fate primarily induced by DNA damage, characterized by irreversible growth arrest in an attempt to stop the damage. Senescence is a cellular response to a stressor and is observed with aging, but also during wound healing and in embryogenic developmental processes. Senescent cells are metabolically active and secrete a multitude of molecules gathered in the senescence-associated secretory phenotype (SASP). The SASP includes inflammatory cytokines, chemokines, growth factors and metalloproteinases, with autocrine and paracrine activities. Among hundreds of molecules, angiopoietin-like 2 (angptl2) is an interesting, although understudied, SASP member identified in various types of senescent cells. Angptl2 is a circulatory protein, and plasma angptl2 levels increase with age and with various chronic inflammatory diseases such as cancer, atherosclerosis, diabetes, heart failure and a multitude of age-related diseases. In this review, we will examine in which context angptl2 was identified as a SASP factor, describe the experimental evidence showing that angptl2 is a marker of senescence in vitro and in vivo, and discuss the impact of angptl2-related senescence in both physiological and pathological conditions. Future work is needed to demonstrate whether the senescence marker angptl2 is a potential clinical biomarker of age-related diseases.

Mesenchymal stromal cell-derived small extracellular vesicles promote neurological recovery and brain remodeling after distal middle cerebral artery occlusion in aged rats

Small extracellular vesicles (sEVs) obtained from mesenchymal stromal cells (MSCs) promote neurological recovery after middle cerebral artery occlusion (MCAO) in young rodents. Ischemic stroke mainly affects aged humans. MSC-sEV effects on stroke recovery in aged rodents had not been assessed. In a head-to-head comparison, we exposed young (4-5 months) and aged (19-20 months) male Sprague-Dawley rats to permanent distal MCAO. At 24 h, 3 and 7 days post-stroke, vehicle or MSC-sEVs (2 × 10⁶ or 2 × 10⁷ MSC equivalents/kg) were intravenously administered. Neurological deficits, ischemic injury, brain inflammatory responses, post-ischemic angiogenesis, and endogenous neurogenesis were evaluated over 28 days. Post-MCAO, aged vehicle-treated rats exhibited more severe motor-coordination deficits evaluated by rotating pole and cylinder tests and larger brain infarcts than young vehicle-treated rats. Although infarct volume was not influenced by MSC-sEVs, sEVs at both doses effectively reduced motor-coordination deficits in young and aged rats. Brain macrophage infiltrates in periinfarct tissue, which were evaluated as marker of a recovery-aversive inflammatory environment, were significantly stronger in aged than young vehicle-treated rats. sEVs reduced brain macrophage infiltrates in aged, but not young rats. The tolerogenic shift in immune balance paved the way for structural brain tissue remodeling. Hence, sEVs at both doses increased periinfarct angiogenesis evaluated by CD31/BrdU immunohistochemistry in young and aged rats, and low-dose sEVs increased neurogenesis in the subventricular zone examined by DCX/BrdU immunohistochemistry. Our study provides robust evidence that MSC-sEVs promote functional neurological recovery and brain tissue remodeling in aged rats post-stroke. This study encourages further proof-of-concept studies in clinic-relevant stroke settings.

Identification of transcriptome alterations in the prefrontal cortex, hippocampus, amygdala and hippocampus of suicide victims

Suicide is one of the leading causes of death globally for all ages, and as such presents a very serious problem for clinicians worldwide. However, the underlying neurobiological pathology remains to a large extent unknown. In order to address this gap, we have carried out a genome-wide investigation of the gene expression in the amygdala, hippocampus, prefrontal cortex and thalamus in post-mortem brain samples obtained from 20 suicide completers and 7 control subjects. By KEGG enrichment analysis indicated we identified novel clusters of downregulated pathways involved in antigen neutralization and autoimmune thyroid disease (amygdala, thalamus), decreased axonal plasticity in the hippocampus. Two upregulated pathways were involved in neuronal death in the hippocampus and olfactory transduction in the thalamus and the prefrontal cortex. Autoimmune thyroid disease pathway was downregulated only in females. Metabolic pathways involved in Notch signaling amino acid metabolism and unsaturated lipid synthesis were thalamus-specific. Suicide-associated changes in the expression of several genes and pseudogenes that point to various functional mechanisms possibly implicated in the pathology of suicide. Two genes (SNORA13 and RNU4-2) involved in RNA processing were common to all brain regions analyzed. Most of the identified gene expression changes were related to region-specific dysregulated manifestation of genetic and epigenetic mechanisms underlying neurodevelopmental disorders (SNORD114-10, SUSd1), motivation, addiction and motor disorders (CHRNA6), long-term depression (RAB3B), stress response, major depression and schizophrenia (GFAP), signal transduction at the neurovascular unit (NEXN) and inhibitory neurotransmission in spatial learning, neural plasticity (CALB2; CLIC6, ENPP1). Some of the differentially expressed genes were brain specific non-coding RNAs involved in the regulation of translation (SNORA13). One, (PARM1) is a potential oncogene and prognostic biomarker for colorectal cancer with no known function in the brain. Disturbed gene expression involved in antigen neutralization, autoimmunity, neural plasticity, stress response, signal transduction at the neurovascular unit, dysregulated nuclear RNA processing and translation and epigenetic imprinting signatures is associated with suicide and point to regulatory non-coding RNAs as potential targets of new drugs development.

A "Janus" face of the RASSF4 signal in cell fate

RASSF4 (Ras-association domain family 4) is a protein-coding gene, regarded as a tumor suppressor regulated by DNA methylation. However, RASSF4 acts as a "Janus" in cell fate: death and survival. This review article focuses on the regulatory mechanisms of RASSF4 on cell death and cell survival and puts forward a comprehensive analysis of the relevant signaling pathways. The participation of RASSF4 in the regulation of intracellular store-operated Ca²⁺ entry also affects cell survival. Moreover, the mechanism of inducing abnormal expression of RASSF4 was summarized. We highlight recent advances in our knowledge of RASSF4 function in the development of cancer and other clinical diseases, which may provide insight into the controversial functions of RASSF4 and its potential application in disease therapy.

Decoding the Transcriptional Response to Ischemic Stroke in Young and Aged Mouse Brain

Ischemic stroke is a well-recognized disease of aging, yet it is unclear how the age-dependent vulnerability occurs and what are the underlying mechanisms. To address these issues, we perform a comprehensive RNA-seq analysis of aging, ischemic stroke, and their interaction in 3- and 18-month-old mice. We assess differential gene expression across injury status and age, estimate cell type proportion changes, assay the results against a range of transcriptional signatures from the literature, and perform unsupervised co-expression analysis, identifying modules of genes with varying response to injury. We uncover downregulation of axonal and synaptic maintenance genetic program, and increased activation of type I interferon (IFN-I) signaling following stroke in aged mice. Together, these results paint a picture of ischemic stroke as a complex age-related disease and provide insights into interaction of aging and stroke on cellular and molecular level.

Reactive astrocytes facilitate vascular repair and remodeling after stroke

Brain injury causes astrocytes to assume a reactive state that is essential for early tissue protection, but how reactive astrocytes affect later reparative processes is incompletely understood. In this study, we show that reactive astrocytes are crucial for vascular repair and remodeling after ischemic stroke in mice. Analysis of astrocytic gene expression data reveals substantial activation of transcriptional programs related to vascular remodeling after stroke. In vivo two-photon imaging provides evidence of astrocytes contacting newly formed vessels in cortex surrounding photothrombotic infarcts. Chemogenetic ablation of a subset of reactive astrocytes after stroke dramatically impairs vascular and extracellular matrix remodeling. This disruption of vascular repair is accompanied by prolonged blood flow deficits, exacerbated vascular permeability, ongoing cell death, and worsened motor recovery. In contrast, vascular structure in the non-ischemic brain is unaffected by focal astrocyte ablation. These findings position reactive astrocytes as critical cellular mediators of functionally important vascular remodeling during neural repair.

RNA-Seq analysis of knocking out the neuroprotective proton-sensitive GPR68 on basal and acute ischemia-induced transcriptome changes and signaling in mouse brain

Brain acid signaling plays important roles in both physiological and disease conditions. One key neuronal metabotropic proton receptor in the brain is GPR68, which contributes to hippocampal long-term potentiation (LTP) and mediates neuroprotection in acidotic and ischemic conditions. Here, to gain greater understanding of GPR68 function in the brain, we performed mRNA-Seq analysis in mice. First, we studied sham-operated animals to determine baseline expression. Compared to wild type (WT), GPR68-/- (KO) brain downregulated genes that are enriched in Gene Ontology (GO) terms of misfolding protein binding, response to organic cyclic compounds, and endoplasmic reticulum chaperone complex. Next, we examined the expression profile following transient middle cerebral artery occlusion (tMCAO). tMCAO-upregulated genes cluster to cytokine/chemokine-related functions and immune responses, while tMCAO-downregulated genes cluster to channel activities and synaptic signaling. For proton-sensitive receptors, tMCAO downregulated ASIC1a and upregulated GPR4 and GPR65, but had no effect on ASIC2, PAC, or GPR68. GPR68 deletion did not alter the expression of these proton receptors, either at baseline or after ischemia. Lastly, we performed GeneVenn analysis of differential genes at baseline and post-tMCAO. Ischemia upregulated the expression of three hemoglobin genes, along with H2-Aa, Ppbp, Siglece, and Tagln, in WT but not in KO. Immunostaining showed that tMCAO-induced hemoglobin localized to neurons. Western blot analysis further showed that hemoglobin induction is GPR68-dependent. Together, these data suggest that GPR68 deletion at baseline disrupts chaperone functions and cellular signaling responses and imply a contribution of hemoglobin-mediated antioxidant mechanism to GPR68-dependent neuroprotection in ischemia.

The Association of Suppressed Hypoxia-Inducible Factor-1 Transactivation of Angiogenesis With Defective Recovery From Cerebral Ischemic Injury in Aged Rats

Elderly patients suffer more brain damage in comparison with young patients from the same ischemic stroke. The present study was undertaken to test the hypothesis that suppressed hypoxia-inducible factor-1 (HIF-1) transcription activity is responsible for defective recovery after ischemic stroke in the elders. Aged and young rats underwent 1-h transient middle cerebral artery occlusion (MCAO) to produce cerebral ischemic injury. The initial cerebral infarct volume in the young gradually declined as time elapsed, but in the aged rats remained the same. The defective recovery in the aged was associated with depressed angiogenesis and retarded neurorestoration. There was no difference in HIF-1α accumulation in the brain between the two age groups, but the expression of HIF-1 regulated genes involved in cerebral recovery was suppressed in the aged. In confirmation, inhibition of HIF-1 transactivation of gene expression in the young suppressed cerebral recovery from MCAO as the same as that observed in the aged rats. Furthermore, a copper metabolism MURR domain 1 (COMMD1) was significantly elevated after MCAO only in the brain of aged rats, and suppression of COMMD1 by siRNA targeting COMMD1 restored HIF-1 transactivation and improved recovery from MCAO-induced damage in the aged brain. These results demonstrate that impaired HIF-1 transcription activity, due at least partially to overexpression of COMMD1, is associated with the defective cerebral recovery from ischemic stroke in the aged rats.

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

Adipose-derived mesenchymal stem cells markedly attenuated brain infarct size and improved neurological function in rats. The mechanisms for neuronal cell death have previously been defined in stress states to suggest that an influx of calcium ions into the neurons activates calpain cleavage of p35 into p25 forming a hyperactive complex that induces cell death. Now we report that p5, a 24-residue peptide derived from p35, offers protection to neurons and endothelial cells in vitro. In vivo administration of human adipose-derived mesenchymal stem cells (hADMSCs) loaded with this therapeutic peptide to post-stroke rats had no effect on the infarct volume. Nevertheless, the treatment led to improvement in functional recovery in spatial learning and memory (water maze), bilateral coordination and sensorimotor function (rotating pole), and asymmetry of forelimb usage (cylinder test). However, the treatment may not impact on cutaneous sensitivity (adhesive tape removal test). In addition, the double immunofluorescence with human cell-specific antibodies revealed that the number of surviving transplanted cells was higher in the peri-infarcted area of animals treated with hADMSCs + P5 than that in hADMSC-treated or control animals, concomitant with reduced number of phagocytic, annexin3-positive cells in the peri-infarcted region. However, the combination therapy did not increase the vascular density in the peri-infarcted area after stroke. In conclusion, administration of hADMSC-loaded p5 peptide to post-stroke rats created conditions that supported survival of drug-loaded hADMSCs after cerebral ischemia, suggesting its therapeutic potential in patients with stroke.

An Integrated Transcriptome Analysis Reveals IGFBP7 Upregulation in Vasculature in Traumatic Brain Injury

Vasculature plays critical roles in the pathogenesis and neurological repair of traumatic brain injury (TBI). However, how vascular endothelial cells respond to TBI at the molecular level has not been systematically reviewed. Here, by integrating three transcriptome datasets including whole cortex of mouse brain, FACS-sorted mouse brain endothelial cells, and single cell sequencing of mouse brain hippocampus, we revealed the key molecular alteration of endothelial cells characterized by increased Myc targets and Epithelial-Mesenchymal Transition signatures. In addition, immunofluorescence staining of patients’ samples confirmed that IGFBP7 was up-regulated in vasculature in response to TBI. TGFβ1, mainly derived from microglia and endothelial cells, sufficiently induces IGFBP7 expression in cultured endothelial cells, and is significantly upregulated in response to TBI. Our results identified IGFBP7 as a potential biomarker of vasculature in response to TBI, and indicate that TGFβ signaling may contribute to the upregulation of IGFBP7 in the vasculature.

Cerebral small vessel disease genomics and its implications across the lifespan

White matter hyperintensities (WMH) are the most common brain-imaging feature of cerebral small vessel disease (SVD), hypertension being the main known risk factor. Here, we identify 27 genome-wide loci for WMH-volume in a cohort of 50,970 older individuals, accounting for modification/confounding by hypertension. Aggregated WMH risk variants were associated with altered white matter integrity (p = 2.5×10-7) in brain images from 1,738 young healthy adults, providing insight into the lifetime impact of SVD genetic risk. Mendelian randomization suggested causal association of increasing WMH-volume with stroke, Alzheimer-type dementia, and of increasing blood pressure (BP) with larger WMH-volume, notably also in persons without clinical hypertension. Transcriptome-wide colocalization analyses showed association of WMH-volume with expression of 39 genes, of which four encode known drug targets. Finally, we provide insight into BP-independent biological pathways underlying SVD and suggest potential for genetic stratification of high-risk individuals and for genetically-informed prioritization of drug targets for prevention trials.

WNT11-Conditioned Medium Promotes Angiogenesis through the Activation of Non-Canonical WNT-PKC-JNK Signaling Pathway

BACKGROUND

We demonstrated that the transduction of Wnt11 into mesenchymal stem cells (MSCs) (MSCWnt11) promotes these cells differentiation into cardiac phenotypes. In the present study, we investigated the paracrine effects of MSCWnt11 on cardiac function and angiogenesis.

METHODS AND RESULTS

Conditioned medium was collected from MSCWnt11 (CdMWnt11) and their control cells (CdMGFP). CdMWnt11, especially obtained from MSCWnt11 exposed to hypoxia, significantly promoted human umbilical vein endothelial cells (HUVECs) migration and increased capillary-like tube (CLT) formation, which was blocked by Wnt11 neutralizing antibody. Wnt11 protein was significantly higher in CdMWnt11 compared to that in CdMGFP. Directly treating HUVECs with recombinant Wnt11 protein significantly increased CLT formation, which was abrogated by treating cells with the JNK inhibitor SP600125, as well as the PKC inhibitor Calphostin-C. Moreover, the transfection of Wnt11 to HUVECs (HWnt11) significantly increased CLT formation and HUVEC migration, as well as upregulated p-pan-PKC and p-JNK expression. Injection of CdMWnt11 into the peri-infarct region in a rat acute myocardial infarction (AMI) model significantly improved cardiac function, reduced infarct size, and increased myocardial blood flow and blood vessel density in the ischemic area.

CONCLUSION

Wnt11 released from MSCWnt11 increased angiogenesis and improved cardiac function via non-canonical Wnt-PKC-JNK dependent pathways.

A Window of Vascular Plasticity Coupled to Behavioral Recovery after Stroke

Stroke causes remodeling of vasculature surrounding the infarct, but whether and how vascular remodeling contributes to recovery are unclear. We established an approach to monitor and compare changes in vascular structure and blood flow with high spatiotemporal precision after photothrombotic infarcts in motor cortex using longitudinal 2-photon and multiexposure speckle imaging in mice of both sexes. A spatially graded pattern of vascular structural remodeling in peri-infarct cortex unfolded over the first 2 weeks after stroke, characterized by vessel loss and formation, and selective stabilization of a subset of new vessels. This vascular structural plasticity was coincident with transient activation of transcriptional programs relevant for vascular remodeling, reestablishment of peri-infarct blood flow, and large improvements in motor performance. Local vascular plasticity was strongly predictive of restoration of blood flow, which was in turn predictive of behavioral recovery. These findings reveal the spatiotemporal evolution of vascular remodeling after stroke and demonstrate that a window of heightened vascular plasticity is coupled to the reestablishment of blood flow and behavioral recovery. Our findings support that neovascularization contributes to behavioral recovery after stroke by restoring blood flow to peri-infarct regions. These findings may inform strategies for enhancing recovery from stroke and other types of brain injury.SIGNIFICANCE STATEMENT An improved understanding of neural repair could inform strategies for enhancing recovery from stroke and other types of brain injury. Stroke causes remodeling of vasculature surrounding the lesion, but whether and how the process of vascular remodeling contributes to recovery of behavioral function have been unclear. Here we used longitudinal in vivo imaging to track vascular structure and blood flow in residual peri-infarct cortex after ischemic stroke in mice. We found that stroke created a restricted period of heightened vascular plasticity that was associated with restoration of blood flow, which was in turn predictive of recovery of motor function. Therefore, our findings support that vascular remodeling facilitates behavioral recovery after stroke by restoring blood flow to peri-infarct cortex.

A NOTCH3 homozygous nonsense mutation in familial Sneddon syndrome with pediatric stroke

Sneddon syndrome is a rare disorder affecting small and medium-sized blood vessels that is characterized by the association of livedo reticularis and stroke. We performed whole-exome sequencing (WES) in 2 affected siblings of a consanguineous family with childhood-onset stroke and identified a homozygous nonsense mutation within the epidermal growth factor repeat (EGFr) 19 of NOTCH3, p.(Arg735Ter). WES of 6 additional cases with adult-onset stroke revealed 2 patients carrying heterozygous loss-of-function variants in putative NOTCH3 downstream genes, ANGPTL4, and PALLD. Our findings suggest that impaired NOTCH3 signaling is one underlying disease mechanism and that bi-allelic loss-of-function mutation in NOTCH3 is a cause of familial Sneddon syndrome with pediatric stroke.

Wnt Pathway: An Emerging Player in Vascular and Traumatic Mediated Brain Injuries

The Wnt pathway, which comprises the canonical and non-canonical pathways, is an evolutionarily conserved mechanism that regulates crucial biological aspects throughout the development and adulthood. Emergence and patterning of the nervous and vascular systems are intimately coordinated, a process in which Wnt pathway plays particularly important roles. In the brain, Wnt ligands activate a cell-specific surface receptor complex to induce intracellular signaling cascades regulating neurogenesis, synaptogenesis, neuronal plasticity, synaptic plasticity, angiogenesis, vascular stabilization, and inflammation. The Wnt pathway is tightly regulated in the adult brain to maintain neurovascular functions. Historically, research in neuroscience has emphasized essentially on investigating the pathway in neurodegenerative disorders. Nonetheless, emerging findings have demonstrated that the pathway is deregulated in vascular- and traumatic-mediated brain injuries. These findings are suggesting that the pathway constitutes a promising target for the development of novel therapeutic protective and restorative interventions. Yet, targeting a complex multifunctional signal transduction pathway remains a major challenge. The review aims to summarize the current knowledge regarding the implication of Wnt pathway in the pathobiology of ischemic and hemorrhagic stroke, as well as traumatic brain injury (TBI). Furthermore, the review will present the strategies used so far to manipulate the pathway for therapeutic purposes as to highlight potential future directions.

Combining Gene-Disease Associations with Single-Cell Gene Expression Data Provides Anatomy-Specific Subnetworks in Age-Related Macular Degeneration

Background: Age-related macular degeneration (AMD) is the most common cause of visual impairment in the developed world. Despite some treatment options for late AMD, there is no intervention that blocks early AMD proceeding to the late and blinding forms. This is partly due to the lack of precise drug targets, despite great advances in genetics, epidemiology, and protein-protein interaction (PPI) networks proposed to be driving the disease pathology. A systems approach to narrow down PPI networks to specific protein drug targets would provide new therapeutic options. Materials and Methods: In this study we analyzed single cell RNAseq (RNA sequencing) datasets of 17 cell types present in choroidal, retinal pigment epithelium (RPE), and neural retina (NR) tissues to explore if a more granular analysis incorporating different cell types exposes more specific pathways and relationships. Furthermore, we developed a novel and systematic gene ontology database (SysGO) to explore if a subcellular classification of processes will further enhance the understanding of the pathogenesis of this complex disorder and its comorbidities with other age-related diseases. Results: We found that 57% of the AMD (risk) genes are among the top 25% expressed genes in ∼1 of the 17 choroidal/RPE/NR cell types, and 9% were among the top 1% of expressed genes. Using SysGO, we identified an enrichment of AMD genes in cell membrane and extracellular anatomical locations, and we found both functional enrichments (e.g., cell adhesion) and cell types (e.g., fibroblasts, microglia) not previously associated with AMD pathogenesis. We reconstructed PPI networks among the top expressed AMD genes for all 17 choroidal/RPE/NR cell types, which provides molecular and anatomical definitions of AMD phenotypes that can guide therapeutic approaches to target this complex disease. Conclusion: We provide mechanism-based AMD endophenotypes that can be exploited in vitro, using computational models and for drug discovery/repurposing.

Electric Stimulation of Neurogenesis Improves Behavioral Recovery After Focal Ischemia in Aged Rats

The major aim of stroke therapies is to stimulate brain repair and to improve behavioral recuperation after cerebral ischemia. Despite remarkable advances in cell therapy for stroke, stem cell-based tissue replacement has not been achieved yet stimulating the search for alternative strategies for brain self-repair using the neurogenic zones of the brain, the dentate gyrus and the subventricular zone (SVZ). However, during aging, the potential of the hippocampus and the SVZ to generate new neuronal precursors, declines. We hypothesized that electrically stimulation of endogenous neurogenesis in aged rats could increase the odds of brain self-repair and improve behavioral recuperation after focal ischemia. Following stroke in aged animals, the rats were subjected to two sessions of electrical non-convulsive stimulation using ear-clip electrodes, at 7- and 24 days after MCAO. Animal were sacrificed after 48 days. We report that electrical stimulation (ES) stimulation of post-stroke aged rats led to an improved functional recovery of spatial long-term memory (T-maze) but not on the rotating pole or the inclined plane, both tests requiring complex sensorimotor skills. Surprisingly, ES had a detrimental effect on the asymmetric sensorimotor deficit. Histologically, there was a robust increase in the number of doublecortin-positive cells in the dentate gyrus and SVZ of the infarcted hemisphere and the presence of a considerable number of neurons expressing tubulin beta III in the infarcted area. Among the gene that were unique to ES, we noted increases in the expression of seizure related 6 homolog like which is one of the physiological substrate of the β-secretase BACE1 involved in the pathophysiology of the Alzheimer’s disease and Igfbp3 and BDNF receptor mRNAs which has been shown to have a neuroprotective effect after cerebral ischemia. However, ES was associated with a long-term down regulation of cortical gene expression after stroke in aged rats suggesting that gene expression in the peri-infarcted cortical area may not be related to electrical stimulation induced-neurogenesis in the subventricular zone and hippocampus.

Angiomodulin (IGFBP7) is a cerebral specific angiocrine factor, but is probably not a blood-brain barrier inducer

BACKGROUND

Several secreted factors have been identified as drivers of cerebral vasculature development and inducers of blood-brain barrier (BBB) differentiation. Vascular endothelial growth factor A (VEGF-A) is central for driving cerebral angiogenesis and Wnt family factors (Wnt7a, Wnt7b and norrin) are central for induction and maintenance of barrier properties. Expressed by developing neural tissue (neuron and glia progenitors), they influence the formation of central nervous system (CNS) vascular networks. Another type of factors are tissue-specific paracrine factors produced by endothelial cells (ECs), also known as 'angiocrine' factors, that provide instructive signals to regulate homeostatic and regenerative processes. Very little is known about CNS angiocrine factors and their role in BBB development. Angiomodulin (AGM) was reported to be expressed by developing vasculature and by pathological tumor vasculature. Here we investigated AGM in the developing CNS and its function as a potential BBB inducer.

METHODS

We analyzed microarray data to identify potential angiocrine factors specifically expressed at early stages of barrier formation. We then tested AGM expression with immunofluorescence and real-time PCR in various organs during development, post-natal and in adults. Permeability induction with recombinant proteins (Miles assay) was used to test potential interaction of AGM with VEGF-A.

RESULTS

Several angiocrine factors are differentially expressed by CNS ECs and AGM is a prominent CNS-specific angiocrine candidate. Contrary to previous reports, we found that AGM protein expression is specific to developing CNS endothelium and not to highly angiogenic developing vasculature in general. In skin vasculature we found that AGM antagonizes VEGF-A-induced vascular hyperpermeability. Finally, CNS AGM expression is not specific to BBB vasculature and AGM is highly expressed in non-BBB choroid-plexus vasculature.

CONCLUSIONS

We propose AGM as a developmental CNS vascular-specific marker. AGM is not a pan-endothelial marker, nor a general marker for developing angiogenic vasculature. Thus, AGM induction in the developing CNS might be distinct from its induction in pathology. While AGM is able to antagonize VEGF-A-induced vascular hyperpermeability in the skin, its high expression levels in non-BBB CNS vasculature does not support its potential role as a BBB inducer. Further investigation including loss-of-function approaches might elucidate AGM function in the developing CNS.

Post-stroke remodeling processes in animal models and humans

After cerebral ischemia, events like neural plasticity and tissue reorganization intervene in lesioned and non-lesioned areas of the brain. These processes are tightly related to functional improvement and successful rehabilitation in patients. Plastic remodeling in the brain is associated with limited spontaneous functional recovery in patients. Improvement depends on the initial deficit, size, nature and localization of the infarction, together with the sex and age of the patient, all of them affecting the favorable outcome of reorganization and repair of damaged areas. A better understanding of cerebral plasticity is pivotal to design effective therapeutic strategies. Experimental models and clinical studies have fueled the current understanding of the cellular and molecular processes responsible for plastic remodeling. In this review, we describe the known mechanisms, in patients and animal models, underlying cerebral reorganization and contributing to functional recovery after ischemic stroke. We also discuss the manipulations and therapies that can stimulate neural plasticity. We finally explore a new topic in the field of ischemic stroke pathophysiology, namely the brain-gut axis.

MicroRNA-22 exerts its neuroprotective and angiogenic functions via regulating PI3K/Akt signaling pathway in cerebral ischemia-reperfusion rats

The aims of this study were to study the effects of miR-2 on cerebral ischemia-reperfusion rats and to explore its further mechanism. Rats were assigned into sham, model, miR-22 control and miR-22 groups. Observation of neurological behaviors at 24 h after operation found that neurological functions were severely damaged in the model and miR-22 control groups and these damages were improved by miR-22. RT-PCR indicated that miR-22 mRNA level in the brain tissue was significantly decreased in the model and miR-22 control groups, but increased in the miR-22 group. TTC staining showed increased percentage of cerebral infarction volume in the model and miR-22 control groups and this increase was reduced by miR-22. Immunohistochemistry showed increased densities of CD34⁺ and VEGF⁺ microvessels in the cortex in the model and miR-22 control groups, which were further increased in the miR-22 group. ELISA showed increased serum VEGF and Ang-1 levels in the model and miR-22 control groups, which were also further increased in the miR-22 group. Western blot analysis showed increased phosphorylation level of PI3K and Akt in brain tissue in the model and miR-22 control groups, which were further increased in the miR-22 group. Administration of LY294002, a specific PI3K pathway inhibitor, significantly reversed all the effects of miR-22 on rats in the model group. miR-22 exerts its neuroprotective and angiogenic functions via the PI3K/Akt signaling pathway, at least partly, in rats under cerebral ischemia-reperfusion.

Scleral ossicles: angiogenic scaffolds, a novel biomaterial for regenerative medicine applications

Given the current prolonged life expectancy, various pathologies affect increasingly the aging subjects. Regarding the musculoskeletal apparatus, bone fragility induces more susceptibility to fractures, often not accompanied by good ability of self-repairing, in particular when critical-size defects (CSD) occur. Currently orthopedic surgery makes use of allografting and autografting which, however, have limitations due to the scarce amount of tissue that can be taken from the donor, the possibility of disease transmission and donor site morbidity. The need to develop new solutions has pushed the field of tissue engineering (TE) research to study new scaffolds to be functionalized in order to obtain constructs capable of promoting tissue regeneration and achieve stable bone recovery over time. This investigation focuses on the most important aspect related to bone tissue regeneration: the angiogenic properties of the scaffold to be used. As an innovative solution, scleral ossicles (SOs), previously characterized as natural, biocompatible and spontaneously decellularized scaffolds used for bone repair, were tested for angiogenic potential and biocompatibility. To reach this purpose, in ovo Chorioallantoic Membrane Assay (CAM) was firstly used to test the angiogenic potential; secondly, in vivo subcutaneous implantation of SOs (in a rat model) was performed in order to assess the biocompatibility and the inflammatory response. Finally, thanks to the analysis of mass spectrometry (LCMSQE), the putative proteins responsible for the SO angiogenic properties were identified. Thus, a novel natural biomaterial is proposed, which is (i) able to induce an angiogenic response in vivo by subcutaneous implantation in a non-immunodeficient animal model, (ii) which does not induce any inflammatory response, and (iii) is useful for regenerative medicine application for the healing of bone CSD.

Sequential Transcriptome Changes in the Penumbra after Ischemic Stroke

To investigate the changes in the expression of specific genes that occur during the acute-to-chronic post-stroke phase, we identified differentially expressed genes (DEGs) between naive cortical tissues and peri-infarct tissues at 1, 4, and 8 weeks after photothrombotic stroke. The profiles of DEGs were subjected to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and gene ontology analyses, followed by string analysis of the protein-protein interactions (PPI) of the products of these genes. We found 3771, 536, and 533 DEGs at 1, 4, and 8 weeks after stroke, respectively. A marked decrease in biological-process categories, such as brain development and memory, and a decrease in neurotransmitter synaptic and signaling pathways were observed 1 week after stroke. The PPI analysis showed the downregulation of Dlg4, Bdnf, Gria1, Rhoa, Mapk8, and glutamatergic receptors. An increase in biological-process categories, including cell population proliferation, cell adhesion, and inflammatory responses, was detected at 4 and 8 weeks post-stroke. The KEGG pathways of complement and coagulation cascades, phagosomes, antigen processing, and antigen presentation were also altered. CD44, C1, Fcgr2b, Spp1, and Cd74 occupied a prominent position in network analyses. These time-dependent changes in gene profiles reveal the unique pathophysiological characteristics of stroke and suggest new therapeutic targets for this disease.

Candesartan Neuroprotection in Rat Primary Neurons Negatively Correlates with Aging and Senescence: a Transcriptomic Analysis

Preclinical experiments and clinical trials demonstrated that angiotensin II AT₁ receptor overactivity associates with aging and cellular senescence and that AT₁ receptor blockers (ARBs) protect from age-related brain disorders. In a primary neuronal culture submitted to glutamate excitotoxicity, gene set enrichment analysis (GSEA) revealed expression of several hundred genes altered by glutamate and normalized by candesartan correlated with changes in expression in Alzheimer's patient's hippocampus. To further establish whether our data correlated with gene expression alterations associated with aging and senescence, we compared our global transcriptional data with additional published datasets, including alterations in gene expression in the neocortex and cerebellum of old mice, human frontal cortex after age of 40, gene alterations in the Werner syndrome, rodent caloric restriction, Ras and oncogene-induced senescence in fibroblasts, and to tissues besides the brain such as the muscle and kidney. The most significant and enriched pathways associated with aging and senescence were positively correlated with alterations in gene expression in glutamate-injured neurons and, conversely, negatively correlated when the injured neurons were treated with candesartan. Our results involve multiple genes and pathways, including CAV1, CCND1, CDKN1A, CHEK1, ICAM1, IL-1B, IL-6, MAPK14, PTGS2, SERPINE1, and TP53, encoding proteins associated with aging and senescence hallmarks, such as inflammation, oxidative stress, cell cycle and mitochondrial function alterations, insulin resistance, genomic instability including telomere shortening and DNA damage, and the senescent-associated secretory phenotype. Our results demonstrate that AT₁ receptor blockade ameliorates central mechanisms of aging and senescence. Using ARBs for prevention and treatment of age-related disorders has important translational value.

Identification of differential gene expression in endothelial cells from young and aged mice using RNA-Seq technique

Aging is a complex phenomenon. Endothelial cell senescence is regarded as a vital characteristic of cardiovascular diseases. This study aims to identify differentially expressed genes in vascular endothelial cells (ECs) of different age groups by RNA sequencing (RNA-Seq) technique, and to explore which molecular pathways differentially expressed genes (DEGs) may enrich in. In this study, we used RNA-Seq to analyze DEGs in primary endothelial cells of young and old mice, and further analyzed them by gene ontology (GO) enrichment and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Our results showed that in total identified 229 of the DEGs, 104 were upregulated and 125 were downregulated in endothelial cells of aged mice compared with young mice. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the involvement of these DEGs in the regulation of morphogenesis of a branching structure, angiogenesis, upregulation of cell proliferation, and extracellular matrix (ECM)-receptor interaction. These results provided a novel insight to understand the molecular mechanisms underlying aortic endothelial cell senescence, and some of the novel candidate genes identified in this study may be valuable in elucidating the molecular mechanisms underlying endothelial cell senescence.

Chemobrain in rats: Behavioral, morphological, oxidative and inflammatory effects of doxorubicin administration

Doxorubicin (DOX) is known to cause cognitive impairments in patients submitted to long-term chemotherapy (deficits also known as chemobrain). The present study investigated whether DOX administration could affect behavior and brain morphology, as well as oxidative and inflammatory status in rats. Male Wistar rats were injected with DOX (2.5 mg/kg/week, 4 weeks, i.p.) or saline. Behavioral analyses were performed. Brains were collected and analyzed by hematoxylin-eosin and luxol fast blue staining techniques and by immunohistochemistry (for glial fibrillary acidic protein expression in astrocytes; GFAP). Serum and brain levels of TNF-α, IL-1β, IL-6, IL-8, IL-10 and CXCL-1 were determined. Oxidative parameters, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), nitric oxide (NO•), brain iron and ferritin levels, as well as reduced and oxidized glutathione (GSH and GSSG, respectively) and thiobarbituric acid reactive substances (TBARS) were also assessed in brain. DOX-injected rats presented cognitive/memory impairments, increased GFAP expression, increased levels of TBARS, NO and GR, but decreased GSSG and ferritin levels in brain homogenate. In addition, increased serum and brain levels of IL-6, IL-8 and CXCL1 were noted in the DOX group, although IL-10 decreased. As DOX has a poor penetration across the blood-brain barrier (BBB), it is proposed that this drug elicits a systemic proinflammatory response with increase of proinflammatory cytokines which cross the BBB and can be involved in the induction of oxidative molecules and proinflammatory cytokines that altogether induce astrogliosis all over the brain. These events may be responsable for chemotherapy-induced cognitive/memory deficits.