Vascular Cell Death Research Articles

Eugenol restrains Angiotensin II-induced death, inflammation and ferroptosis of vascular smooth muscle cells by targeting STAT3/HMGB2 axis.

Eugenol has been found to inhibit a variety of disease processes, including abdominal aortic aneurysm (AAA) formation. However, the specific role and the underlying molecular mechanism of Eugenol in AAA progression need to be further revealed. Vascular smooth muscle cells (VSMCs) were pre-treated with Eugenol, followed by treated with Angiotensin II (Ang-II). VSMCs were transfected with HMGB2 siRNA or overexpression vector and treated with Ang-II to confirm the effect of HMGB2 on AAA progression. Cell proliferation and death were determined using cell counting kit 8 (CCK8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay and flow cytometry. Inflammatory factors were examined by ELISA. Fe2+, glutathione (GSH) and malondialdehyde (MDA) levels were tested to evaluate cell ferroptosis. The protein levels of ferroptosis-related markers, high mobility group box 2 (HMGB2) and STAT3 were measured using western blot. Human AAA tissues and normal abdominal aortic tissues were collected to detect HMGB2 mRNA expression by quantitative real-time PCR. The interaction between HMGB2 and STAT3 was confirmed by chromatin immunoprecipitation (ChIP) assay and dual-luciferase reporter assay. Eugenol enhanced VSMCs proliferation, while restrained Ang-II-induced death, inflammation and ferroptosis. HMGB2 was upregulated in AAA tissues and Ang-II-induced VSMCs, and Eugenol significantly decreased HMGB2 expression. HMGB2 knockdown reduced Ang-II-induced VSMCs death, inflammation and ferroptosis, Besides, HMGB2 overexpression abolished the effect of Eugenol on Ang-II-induced VSMCs injury. Transcription factor STAT3 bound to HMGB2 promoter region to increase its expression. In addition, Eugenol decreased STAT3 expression to regulate HMGB2. Eugenol could slow down the development of AAA, which might be achieved by regulating STAT3/HMGB2 axis.

Intracellular Iron Deficiency and Abnormal Metabolism, Not Ferroptosis, Contributes to Homocysteine-Induced Vascular Endothelial Cell Death.

Background/Objectives: Homocysteine (Hcy) and iron are factors co-related with the progression of cardiovascular diseases. The vascular endothelium is an important barrier for physiological homeostasis, and its impairment initiates cardiovascular injury. However, the mechanism underlying Hcy-caused vascular endothelial cell injury and the participation of iron are not fully elucidated. This study aims to investigate the Hcy-induced vascular endothelial injury and iron metabolism dysfunction as well as the underlying molecular mechanism. Methods: Human umbilical vein endothelial cells (HUVECs) were employed as the experimental model to examine the Hcy-induced endothelial injury and its underlying mechanism via various biochemical assays. Results: Hcy suppressed the cell viability and proliferation and caused cell death in a concentration-dependent manner. Hcy induced cell cycle arrest, apoptosis, and autophagy as well as impairment of intracellular energy metabolism. Hcy disrupted the intracellular antioxidant system and mitochondrial function by increasing intracellular ROS, MDA and mitochondrial content, and decreasing the SOD activity and mitochondrial membrane potential. Hcy significantly reduced the GSH-Px activity along with the accumulation of intracellular GSH in a concentration-dependent manner. Ferroptosis inhibitors, Ferrostatin-1 (Fer-1), and Deferoxamine (DFO) significantly decreased the Hcy-caused cytotoxicity accompanied by a reduction in dysregulated mitochondria content, but only DFO ameliorated the elevation of intracellular ROS, and neither Fer-1 nor DFO affected the Hcy-caused reduction in intracellular ATP. In addition, Hcy decreased the intracellular concentration of iron, and supplementing Hcy with various concentrations of Fe3+ increased the cell viability and decreased the LDH release in a concentration-dependent manner. Hcy dramatically decreased the mRNA expression level of transferrin receptor while increasing the mRNA expression levels of transferrin, ferritin light chain, ferritin heavy chain, ferroportin, and SLC7A11. Moreover, Hcy suppressed the protein expression of phospho-Akt, phospho-mTOR, Beclin-1, LC3A/B, Nrf2, HO-1, phospho-MEK1/2, phospho-ERK1/2, and Caspase-3 in concentration- and time-dependent manners. Conclusions: Hcy-induced vascular endothelial injury is likely to be associated with apoptosis and autophagy, but not ferroptosis. The key underlying mechanisms are involved in the disruption of the intracellular antioxidant system and iron metabolism via regulation of PI3K/Akt/mTOR, MAPKs, Nrf2/HO-1, and iron metabolism.

The use of a protein network analysis to explore the complexity of early skin inflammation after oronasal mask application- A pilot study

Medical devices, such as non-invasive ventilation masks, save lives in health care settings but can be a cause of tissue injuries due to the pressure and shear loads on skin and soft tissue. These pressure injuries could be painful for the individual and cause a significant economic impact on healthcare providers. In the etiology of device related pressure ulcers, inflammation plays an important role. However, the exact nature and timing of inflammatory biomarker upregulation is still unknown in the early stages of skin damage. This study aimed to explore the inflammatory profile of vulnerable skin sites following non-invasive mask application on a convenience sample of eleven hospital patients. Seventy-one inflammatory proteins were explored from sebum sampled at the skin surface after oronasal mask application. A multivariate analysis to investigate differences between loaded and control site was conducted, with a protein network analysis used to explore interactions in the early inflammation. The study revealed that 21 cytokines and chemokines were important for the separation between loaded and control site. These proteins were associated with remodeling of tissue, vascular wound healing and/or cell death.

The suppression of FSP1 expression via NRF2 promotes ferroptosis induced by reactive oxygen species in vascular smooth muscle cells

Death of vascular smooth muscle cells (VSMC) induced by reactive oxygen species (ROS) may occur as ferroptosis, contributing to atherosclerotic plaque instability and rupture. Although it is involved in ROS-induced VSMC death, the role of nuclear transcription factors erythroid 2 related factor 2 (NRF2) in ferroptosis remains unclear. This study was designed to determine the coupling between NRF2 and antioxidant ferroptosis suppressor protein 1 (FSP1) in ROS-induced VSMC ferroptosis. We exposed mouse aortic VSMCs to hydrogen peroxide (H2O2), and cell death was characterized by increased NRF2 expression and inhibition of FSP1 expression. The results demonstrated that VSMC exposure to H2O2 emerged as the characteristic of ferroptosis·H2O2 promoted the expression and nuclear translocation of NRF2 and downregulated FSP1 expression. These data imply a novel and important role for NRF2/FSP1 in ferroptosis for treating VSMCs ferroptosis-associated diseases.

Activation of the IKK2/NF-κB pathway in VSMCs inhibits calcified vascular stiffness in CKD.

IKK2/NF-κB pathway-mediated inflammation in vascular smooth muscle cells (VSMCs) has been proposed to be an etiologic factor in medial calcification and stiffness. However, the role of the IKK2/NF-κB pathway in medial calcification remains to be elucidated. In this study, we found that chronic kidney disease (CKD) induces inflammatory pathways through the local activation of the IKK2/NF-κB pathway in VMSCs associated with calcified vascular stiffness. Despite reducing the expression of inflammatory mediators, complete inhibition of the IKK2/NF-κB pathway in vitro and in vivo unexpectedly exacerbated vascular mineralization and stiffness. In contrast, activation of NF-κB by SMC-specific IκBα deficiency attenuated calcified vascular stiffness in CKD. Inhibition of the IKK2/NF-κB pathway induced cell death of VSMCs by reducing anti-cell death gene expression, whereas activation of NF-κB reduced CKD-dependent vascular cell death. In addition, increased calcification of extracellular vesicles through the inhibition of the IKK2/NF-κB pathway induced mineralization of VSMCs, which was significantly reduced by blocking cell death in vitro and in vivo. This study reveals that activation of the IKK2/NF-κB pathway in VSMCs plays a protective role in CKD-dependent calcified vascular stiffness by reducing the release of apoptotic calcifying extracellular vesicles.

Design of a Zn-based nanozyme injectable multifunctional hydrogel with ROS scavenging activity for myocardial infarction therapy

The existing strategies for myocardial infarction therapy mainly focus on reinstating myocardial blood supply, often disregarding the intrinsic and intricate microenvironment created by elevated levels of reactive oxygen species (ROS) that accompanies myocardial infarction. This microenvironment entails cardiomyocytes apoptosis, substantial vascular cell death, excessive inflammatory infiltration and fibrosis. In such situation, the present study introduces a zinc-based nanozyme injectable multifunctional hydrogel, crafted from ZIF-8, to counteract ROS effects after myocardial infarction. The hydrogel exhibits both superoxide dismutase (SOD)-like and catalase (CAT)-like enzymatic activities, proficiently eliminating surplus ROS in the infarcted region and interrupting ROS-driven inflammatory cascades. Furthermore, the hydrogel's exceptional immunomodulatory ability spurs a notable transformation of macrophages into the M2 phenotype, effectively neutralizing inflammatory factors and indirectly fostering vascularization in the infarcted region. For high ROS and demanding for zinc of the infarcted microenvironment, the gradual release of zinc ions as the hydrogel degrades further enhances the bioactive and catalytic performance of the nanozymes, synergistically promoting cardiac function post myocardial infarction. In conclusion, this system of deploying catalytic nanomaterials within bioactive matrices for ROS-related ailment therapy not only establishes a robust foundation for biomedical material development, but also promises a holistic approach towards addressing myocardial infarction complexities. Statement of significanceMyocardial infarction remains the leading cause of death worldwide. However, the existing strategies for myocardial infarction therapy mainly focus on reinstating myocardial blood supply. These therapies often ignore the intrinsic and intricate microenvironment created by elevated levels of reactive oxygen species (ROS). Hence, we designed an injectable Zn-Based nanozyme hydrogel with ROS scavenging activity for myocardial infarction therapy. ALG-(ZIF-8) can significantly reduce ROS in the infarcted area and alleviate the ensuing pathological process. ALG-(ZIF-8) gradually releases zinc ions to participate in the repair process and improves cardiac function. Overall, this multifunctional hydrogel equipped with ZIF-8 makes full use of the characteristics of clearing ROS and slowly releasing zinc ions, and we are the first to test the therapeutic efficacy of Zinc-MOFs crosslinked-alginate hydrogel for myocardial infarction.

Impaired neuronal activity as a potential factor contributing to the underdeveloped cerebrovasculature in a young Parkinson’s disease mouse model

Misfolding of α-synuclein (α-Syn) in the brain causes cellular dysfunction, leading to cell death in a group of neurons, and consequently causes the progression of Parkinson’s disease (PD). Although many studies have demonstrated the pathological connections between vascular dysfunction and neurodegenerative diseases, it remains unclear how neuronal accumulation of α-Syn affects the structural and functional aspects of the cerebrovasculature to accelerate early disease progression. Here, we demonstrated the effect of aberrant α-Syn expression on the brain vasculature using a PD mouse model expressing a familial mutant form of human α-Syn selectively in neuronal cells. We showed that young PD mice have an underdeveloped cerebrovasculature without significant α-Syn accumulation in the vasculature. During the early phase of PD, toxic α-Syn was selectively increased in neuronal cells, while endothelial cell proliferation was decreased in the absence of vascular cell death or neuroinflammation. Instead, we observed altered neuronal activation and minor changes in the activity-dependent gene expression in brain endothelial cells (ECs) in young PD mice. These findings demonstrated that neuronal expression of mutant α-Syn in the early stage of PD induces abnormal neuronal activity and contributes to vascular patterning defects, which could be associated with a reduced angiogenic potential of ECs.

Photodynamic therapy for arthritis: A promising therapeutic strategy

AbstractPhotodynamic therapy (PDT) is a novel therapy that combines photosensitizers, light, and oxygen molecules to treat diseases such as joint lesions and microbial infections through photodynamic reactions. The photosensitizers are activated under specific wavelengths of laser radiation to generate reactive oxygen species, which alter the microenvironment of the diseased tissue, cause ischemia and target cell death, and thus effectively treat cancer. Now that there is growing evidence that nonlethal doses of PDT reduce inflammation and treat infections in multiple animal models of arthritis, PDT should be considered as a new option for the treatment of arthritis. This article presents a literature review of published original articles and review articles concerning photodynamic therapy and arthritis. We conducted a comprehensive literature search in PubMed, Web of Science and Google Scholar databases, excluding duplicated and irrelevant studies. In cases of duplicated research, we selected articles with higher impact factors for the review. In this review, we summarize the application and progress of PDT in the treatment of rheumatoid arthritis, osteoarthritis, psoriatic arthritis, and infectious arthritis, and clarify the advantages and limitations of PDT for arthritis. PDT offers therapeutic value for patients with inflammatory and infectious arthritis through promoting vascular occlusion, cell death, and antibacterial therapy.

Alzheimer's Disease: Novel Targets and Investigational Drugs for Disease Modification.

Novel agents addressing non-amyloid, non-tau targets in Alzheimer's Disease (AD) comprise 70% of the AD drug development pipeline of agents currently in clinical trials. Most of the target processes identified in the Common Alzheimer's Disease Research Ontology (CADRO) are represented by novel agents in trials. Inflammation and synaptic plasticity/neuroprotection are the CADRO categories with the largest number of novel candidate therapies. Within these categories, there are few overlapping targets among the test agents. Additional categories being evaluated include apolipoprotein E [Formula: see text] 4 (APOE4) effects, lipids and lipoprotein receptors, neurogenesis, oxidative stress, bioenergetics and metabolism, vascular factors, cell death, growth factors and hormones, circadian rhythm, and epigenetic regulators. We highlight current drugs being tested within these categories and their mechanisms. Trials will be informative regarding which targets can be modulated to produce a slowing of clinical decline. Possible therapeutic combinations of agents may be suggested by trial outcomes. Biomarkers are evolving in concert with new targets and novel agents, and biomarker outcomes offer a means of supporting disease modification by the putative treatment. Identification of novel targets and development of corresponding therapeutics offer an important means of advancing new treatments for AD.

Atorvastatin rescues vascular endothelial injury in hypertension by WWP2-mediated ubiquitination and degradation of ATP5A

As a widely used lipid-lowering drug in clinical practice, atorvastatin is widely recognized for its role in protecting vascular endothelium in the cardiovascular system. However, a clear mechanistic understanding of its action is lacking. Here, we found that atorvastatin counteracted angiotensin II-induced vascular endothelial injury in mice with hypertension. Mechanistically, atorvastatin up-regulated WWP2, a E6AP C-terminus (HECT)-type E3 ubiquitin ligase with an essential role in regulating protein ubiquitination and various biological processes, thereby rescuing vascular endothelial injury. By ubiquitinating ATP5A (ATP synthase mitochondrial F1 complex subunit alpha), WWP2 degraded ATP5A via the proteasome pathway, stabilizing Bcl-2/Bax in the mitochondrial pathway of apoptosis. Moreover, atorvastatin further ameliorated death of vascular endothelial cells and improved vascular endothelial functions under WWP2 overexpression, whereas WWP2 knockout abrogated these beneficial effects of atorvastatin. Furthermore, we generated endothelial cell-specific WWP2 knockout mice, and this WWP2-mediated mechanism was faithfully recapitulated in vivo. Thus, we propose that activation of a WWP2-dependent pathway that is pathologically repressed in damaged vascular endothelium under hypertension is a major mechanism of atorvastatin. Our findings are also pertinent to develop novel therapeutic strategies for vascular endothelial injury-related cardiovascular diseases.

Sparing and enhancing dose protraction effects for radiation damage to the aorta of wild-type mice

Purpose Our previous work indicated the greater magnitude of damage to the thoracic aorta at 6 months after starting 5 Gy irradiation in descending order of exposure to X-rays in 25 fractions > acute X-rays > acute γ-rays > X-rays in 100 fractions ≫ chronic γ-rays, in which the limitations of the study included a lack of data for fractionated γ-ray exposure. To better understand effects of dose protraction and radiation quality, the present study examined changes after exposure to γ-rays in 25 fractions, and compared its biological effectiveness with five other irradiation regimens. Materials and Methods Male C57BL/6J mice received 5 Gy of 137Cs γ-rays delivered in 25 fractions spread over six weeks. At 6 months after starting irradiation, mice were subjected to echocardiography, followed by tissue sampling. The descending thoracic aorta underwent scanning electron microscopy, immunofluorescence staining and histochemical staining. The integrative analysis of multiple aortic endpoints was conducted for inter-regimen comparisons. Results Exposure to γ-rays in 25 fractions induced vascular damage (evidenced by increases in endothelial detachment and vascular endothelial cell death, decreases in endothelial waviness, CD31, endothelial nitric oxide synthase and vascular endothelial cadherin), inflammation (evidenced by increases in tumor necrosis factor α, CD68 and F4/80) and fibrosis (evidenced by increases in transforming growth factor β1, alanine blue stain and intima-media thickness). The integrative analysis revealed biological effectiveness in descending order of exposure to X-rays in 25 fractions > acute X-rays > γ-rays in 25 fractions > acute γ-rays > X-rays in 100 fractions ≫ chronic γ-rays. Conclusions The results suggest that dose protraction effects on aortic damage depend on radiation quality, and are not a simple function of dose rate and the number of fractions.

Differential Effects of High Fat Diets on Resilience to H2O2-Induced Cell Death in Mouse Cerebral Arteries: Role for Processed Carbohydrates.

High fat, western-style diets increase vascular oxidative stress. We hypothesized that smooth muscle cells and endothelial cells adapt during the consumption of high fat diets to become more resilient to acute oxidative stress. Male C57Bl/6J mice were fed a western-style diet high in fat and processed carbohydrates (WD), a high fat diet that induces obesity (DIO), or their respective control (CD) and standard (SD) diets for 16 weeks. Posterior cerebral arteries (PCAs) were isolated and pressurized for study. During acute exposure to H2O2 (200 µM), smooth muscle cell and endothelial cell death were reduced in PCAs from WD, but not DIO mice. WD selectively attenuated mitochondrial membrane potential depolarization and vessel wall Ca2+ influx during H2O2 exposure. Selective inhibition of transient receptor potential (TRP) V4 or TRPC3 channels reduced smooth muscle cell and endothelial cell death in concert with the vessel wall [Ca2+]i response to H2O2 for PCAs from CD mice and eliminated differences between CD and WD. Inhibiting Src kinases reduced smooth muscle cell death along with [Ca2+]i response to H2O2 only in PCAs from CD mice and eliminated differences between diets. However, Src kinase inhibition did not alter endothelial cell death. These findings indicate that consuming a WD, but not high fat alone, leads to adaptations that limit Ca2+ influx and vascular cell death during exposure to acute oxidative stress.

New Insights into the Role of Ferroptosis in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the principal cause of disease burden and death worldwide. Ferroptosis is a new form of regulated cell death mainly characterized by altered iron metabolism, increased polyunsaturated fatty acid peroxidation by reactive oxygen species, depletion of glutathione and inactivation of glutathione peroxidase 4. Recently, a series of studies have indicated that ferroptosis is involved in the death of cardiac and vascular cells and has a key impact on the mechanisms leading to CVDs such as ischemic heart disease, ischemia/reperfusion injury, cardiomyopathies, and heart failure. In this article, we reviewed the molecular mechanism of ferroptosis and the current understanding of the pathophysiological role of ferroptosis in ischemic heart disease and in some cardiomyopathies. Moreover, the comprehension of the machinery governing ferroptosis in vascular cells and cardiomyocytes may provide new insights into preventive and therapeutic strategies in CVDs.

Vascular dysfunction in HFpEF: Potential role in the development, maintenance, and progression of the disease.

Heart failure with preserved ejection fraction (HFpEF) is a complex, heterogeneous disease characterized by autonomic imbalance, cardiac remodeling, and diastolic dysfunction. One feature that has recently been linked to the pathology is the presence of macrovascular and microvascular dysfunction. Indeed, vascular dysfunction directly affects the functionality of cardiomyocytes, leading to decreased dilatation capacity and increased cell rigidity, which are the outcomes of the progressive decline in myocardial function. The presence of an inflammatory condition in HFpEF produced by an increase in proinflammatory molecules and activation of immune cells (i.e., chronic low-grade inflammation) has been proposed to play a pivotal role in vascular remodeling and endothelial cell death, which may ultimately lead to increased arterial elastance, decreased myocardium perfusion, and decreased oxygen supply to the tissue. Despite this, the precise mechanism linking low-grade inflammation to vascular alterations in the setting of HFpEF is not completely known. However, the enhanced sympathetic vasomotor tone in HFpEF, which may result from inflammatory activation of the sympathetic nervous system, could contribute to orchestrate vascular dysfunction in the setting of HFpEF due to the exquisite sympathetic innervation of both the macro and microvasculature. Accordingly, the present brief review aims to discuss the main mechanisms that may be involved in the macro- and microvascular function impairment in HFpEF and the potential role of the sympathetic nervous system in vascular dysfunction.

Иммунный статус и спектр цитокинов как прогностические признаки риска тяжело-го течения заболевания и эффективности интенсивной терапии пациентов с коронавирусной инфекцией covid-19

The pandemic caused by a new strain of the SARS-CoV-2 coronavirus has swept the whole world but effective methods for treating this severe pathology have not yet been created. It has now been established that a risk of a severe course of COVID-19 is not so much a patient's age itself, but so-called age-related diseases; the renin-angiotensin system (RAS) is directly or indirectly involved into their development. The SARS-CoV-19 virus interacts with one of the main regulatory elements of this system, ACE2, and disrupts the balance between the two RAS branches. This ultimately manifests itself in an increase in levels of angiotensin II, which, through binding to the angiotensin type 1 receptor (AT1R), causes a number of pathological conditions, including hypertension, atherosclerosis, and cardiovascular diseases, enhances cell proliferation, apoptosis, death of vascular endothelial cells, etc. This process has been described in many reviews by Russian and foreign authors. However, cells of innate and adaptive immunity are another less well-described but no less important target of angiotensin II. The consequences of this interaction are analyzed in detail in this review. With COVID-19, dendritic cells are activated, macrophage proliferation and neutrophil infiltration increase with further involvement of CD4-lymphocytes and other cellular elements of the adaptive immunity in this process. Hyperactivation of the immune system is accompanied with the release of a large amount of pro-inflammatory cytokines, which can lead to the occurrence of a cytokine storm. The picture is aggravated by the inhibitory effect produced by the virus itself on the synthesis of signaling interferons at initial stages in its internalization into the cell. A separate section in the review ad-dresses the problem how to predict a risk of a developing serious condition and search for its predictors by analyzing the state of the RAS and ratios of key cellular elements in the immune system. This is extremely important for making decisions concerning the amount of necessary medical care and strategies for subsequent treatment.

Immune status and cytokine spectrum as predictors of the risk of severe disease and performance indicators of intensive therapy in patients with coronavirus infection COVID-19

The pandemic caused by a new strain of the SARS-CoV-2 coronavirus has swept the whole world but effective methods for treating this severe pathology have not yet been created. It has now been established that a risk of a severe course of COVID-19 is not so much a patient's age itself, but so-called age-related diseases; the renin-angiotensin system (RAS) is directly or indirectly involved into their development. The SARS-CoV-19 virus interacts with one of the main regulatory elements of this system, ACE2, and disrupts the balance between the two RAS branches. This ultimately manifests itself in an increase in levels of angiotensin II, which, through binding to the angiotensin type 1 receptor (AT1R), causes a number of pathological conditions, including hypertension, atherosclerosis, and cardiovascular diseases, enhances cell proliferation, apoptosis, death of vascular endothelial cells, etc. This process has been described in many reviews by Russian and foreign authors. However, cells of innate and adaptive immunity are another less well-described but no less important target of angiotensin II. The consequences of this interaction are analyzed in detail in this review. With COVID-19, dendritic cells are activated, macrophage proliferation and neutrophil infiltration increase with further involvement of CD4-lymphocytes and other cellular elements of the adaptive immunity in this process. Hyperactivation of the immune system is accompanied with the release of a large amount of pro-inflammatory cytokines, which can lead to the occurrence of a cytokine storm. The picture is aggravated by the inhibitory effect produced by the virus itself on the synthesis of signaling interferons at initial stages in its internalization into the cell. A separate section in the review ad-dresses the problem how to predict a risk of a developing serious condition and search for its predictors by analyzing the state of the RAS and ratios of key cellular elements in the immune system. This is extremely important for making decisions concerning the amount of necessary medical care and strategies for subsequent treatment.

Abstract 268: Single Cell Gene Expression Of Brachial Artery In Response To Increased Shear Stress

Blood flow dynamics modulate vascular development, homeostasis, and contribute to vascular pathobiology. However, it is unknown how shear stress influences cellular transcriptomics of the arterial wall. Two-stage hemodialysis access surgeries provide an opportunity to compare native vessel to vessel after exposure to significantly altered hemodynamics. Single-cell sequencing was performed on brachial artery samples obtained from 3 patients at the time of 1 st and 2 nd stage surgery. Arterial cellular composition and temporal changes in gene expression were quantified after sequencing and functional analyses were performed on differentially expressed genes. Compositional changes and gene expression dynamics were highest in the smooth muscle cell (SMC) populations followed by fibroblasts. SMCs were clustered into contractile (classical) and “modified” populations, with the latter having lower expression of contractile markers. Downregulation of transcription factor ARNTL was the most significant controller in contractile SMCs and fibroblasts, and second behind HIF1α in modified SMCs. Macrophages had a significant increase in composition, but few dynamic genes suggest a return to quiescence. Endothelial cells showed minimal changes with dynamic genes responding to mechanical stimulus. Ingenuity pathway analysis revealed activation of EIF2 signaling in both SMC and fibroblast clusters, promoting translation. The top divergent pathway among SMC clusters is PI3/AKT signaling, with increased vascular remodeling, proliferation and cell death in the contractile group. Cellular processes are overall downregulated in modified SMCs, which represent the majority of SMCs after vascular adaption. This study is the first single-cell characterization of normal human artery and its cellular response to increased hemodynamic forces, specifically detailing cellular compositional changes and their associated dynamic genes.

Angiopoietin 2 Is Associated with Vascular Necroptosis Induction in Coronavirus Disease 2019 Acute Respiratory Distress Syndrome

Vascular injury is a well-established, disease-modifying factor in acute respiratory distress syndrome (ARDS) pathogenesis. Recently, coronavirus disease 2019 (COVID-19)–induced injury to the vascular compartment has been linked to complement activation, microvascular thrombosis, and dysregulated immune responses. This study sought to assess whether aberrant vascular activation in this prothrombotic context was associated with the induction of necroptotic vascular cell death. To achieve this, proteomic analysis was performed on blood samples from COVID-19 subjects at distinct time points during ARDS pathogenesis (hospitalized at risk, N = 59; ARDS, N = 31; and recovery, N = 12). Assessment of circulating vascular markers in the at-risk cohort revealed a signature of low vascular protein abundance that tracked with low platelet levels and increased mortality. This signature was replicated in the ARDS cohort and correlated with increased plasma angiopoietin 2 levels. COVID-19 ARDS lung autopsy immunostaining confirmed a link between vascular injury (angiopoietin 2) and platelet-rich microthrombi (CD61) and induction of necrotic cell death [phosphorylated mixed lineage kinase domain-like (pMLKL)]. Among recovery subjects, the vascular signature identified patients with poor functional outcomes. Taken together, this vascular injury signature was associated with low platelet levels and increased mortality and can be used to identify ARDS patients most likely to benefit from vascular targeted therapies.

Abstract 53: Covid-19 Spike-protein Causes Cerebrovascular Rarefaction And Deteriorates Cognitive Functions In A Mouse Model Of Humanized ACE2

COVID-19 pandemic has affected our health and economy. Clinical trials confirmed multiple neurological symptoms due to COVID-19, ranging from headaches, insomnia to stroke, and encephalopathy. More studies are required to unravel the cellular and molecular mechanisms to find a cure for these neurological symptoms. Here, we investigate the effect of COVID-19 spike protein (S-protein) on the cerebrovasculature and cognitive functions in two mouse models that express humanized ACE-2 (h ACE2), a receptor essential for cellular infection and COVID-19 internalization. We hypothesize that COVID-19 S-protein causes cognitive dysfunction via the deterioration of cerebrovascular functions. Methods: S-protein was either injected intravenously or directly into the hippocampus of K-18 (h ACE2 in epithelial cells) or global h-ACE2 knock-in (h ACE2 KI) mice or wild-type mice. Cognitive functions were assessed by Y-maze and Barnes maze. Cerebrovascular density was determined using confocal 3-D image reconstruction. Human brain microvascular endothelial cells (HBMVEC) were treated with S-protein and assessed for apoptosis and inflammatory markers using immunoblotting and RT-PCR. K-18 and h-ACE2 KI mice received intraocular injections of S-protein; retinas were evaluated for vascular cell death and inflammation. Results: S-protein injections caused significant deterioration in memory and learning function of K-18 and h-ACE2 KI mice but not in the wild-type mice (P<0.05). S-protein significantly increased inflammatory mediators, cytokine production, and apoptosis in the brains and HBMVECs (P<0.05). Significant cerebrovascular rarefaction was detected only in K-18 and h-ACE2 KI mice compared to wild-type mice (P<0.05). Retinal vascular cell death and inflammation were significantly increased after S-protein injection. (P<0.05) Conclusions: COVID-19 spike protein decreases cognitive function via increased endothelial cell inflammation, apoptosis, and cerebrovascular rarefaction. Humanized ACE2 animal models are excellent and reliable for investigating the neurological symptoms of COVID-19.

Cross-Talk between Amyloid, Tau Protein and Free Radicals in Post-Ischemic Brain Neurodegeneration in the Form of Alzheimer's Disease Proteinopathy.

Recent years have seen remarkable progress in research into free radicals oxidative stress, particularly in the context of post-ischemic recirculation brain injury. Oxidative stress in post-ischemic tissues violates the integrity of the genome, causing DNA damage, death of neuronal, glial and vascular cells, and impaired neurological outcome after brain ischemia. Indeed, it is now known that DNA damage and repair play a key role in post-stroke white and gray matter remodeling, and restoring the integrity of the blood-brain barrier. This review will present one of the newly characterized mechanisms that emerged with genomic and proteomic development that led to brain ischemia to a new level of post-ischemic neuropathological mechanisms, such as the presence of amyloid plaques and the development of neurofibrillary tangles, which further exacerbate oxidative stress. Finally, we hypothesize that modified amyloid and the tau protein, along with the oxidative stress generated, are new key elements in the vicious circle important in the development of post-ischemic neurodegeneration in a type of Alzheimer’s disease proteinopathy.