Adenovirus-mediated overexpression of glutathione-s-transferase mitigates transplant arteriosclerosis in rabbit carotid allografts

Early, rapidly progressive vasculopathy in a transplanted heart: A possible complication of COVID-19

The epidemic caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has had a significant global impact, especially on immunosuppressed populations such as heart transplant recipients. While SARS-CoV-2 initially infects the respiratory system, cardiovascular complications induced by coronavirus disease 2019 (COVID-19) include cardiac arrest, myocardial infarction, heart failure, myocarditis, arrhythmia, acute myocyte injury, thrombotic events, and cardiogenic shock. Here, we present a case of a 45-year-old African American male who tested positive for COVID-19 infection six months after receiving a heart transplant. The patient was asymptomatic initially, but two weeks later he developed dyspnea, early satiety, and abdominal bloating. The patient was admitted to the hospital for acute renal failure and subsequently diagnosed with moderate acute T cell-mediated allograft rejection (Grade 2R) by endomyocardial biopsy. Three months after testing positive for COVID-19, the patient suffered a sudden cardiac death. At autopsy, the epicardium was diffusely edematous and showed vascular congestion. The coronary arteries showed a striking concentric narrowing of lumens and diffusely thickened arterial walls of all major extramural arteries deemed consistent with a rapidly progressive form of cardiac allograft vasculopathy (CAV). SARS-CoV-2 nucleocapsid protein was localized by immunohistochemistry (IHC) in endothelial cells of venules and capillaries within the epicardium. Our localization of SARS-CoV-2 in coronary vessel endothelial cells by IHC suggests that endothelial cell infection, endotheliitis, and immune-related inflammation may be a primary mechanism of vascular injury. The present case represents an early onset rapidly progressive form of CAV. This case may be the first case of post-transplant arteriopathy occurring in such a short time that includes corresponding autopsy, surgical pathology, and IHC data.

DNA methylation and mRNA expression of glutathione S-transferase alpha 4 are associated with intracranial aneurysms in a gender-dependent manner

Objective: We performed a case-control study to investigate the correlation between DNA methylation and mRNA expression of the glutathione S-transferase alpha 4 (GSTA4) gene and the risk of intracranial aneurysm (IA) in the Chinese Han population. Methods: After propensity score matching, 44 pairs of cases and controls were collected in this study. Fasting blood samples were collected for DNA and RNA extraction within 24 h of admission. Nine CpG dinucleotides were selected from the GSTA4 promoter region for DNA methylation pyrosequencing. mRNA expression of GSTA4 was measured by quantitative real-time polymerase chain reaction (RT-qPCR). In vitro cell experiments were conducted to verify the association between 5-aza-2'-deoxycytidine induced DNA hypomethylation and GSTA4 mRNA expression. Results: The mean methylation level of GSTA4 was much lower in IA patients, especially in IA patients, especially in unruptured IA (UIA), than that in controls (IA vs. Control, p < .001; ruptured IA (RIA) vs. Control, p = .005; UIA vs. Control, p < .001). With sex stratification, we further found that the association between GSTA4 methylation and IA risk presented only in women (mean methylation level: IA vs. Control, p < .001; RIA vs. Control, p = .009; UIA vs. Control, p < .001). GSTA4 mRNA expression was significantly higher in the IA group than in the control group (p < .01) and negatively correlated with DNA methylation in all individuals (r = -.746, p < .001). DNA hypomethylation can increase GSTA4 mRNA expression in human primary artery smooth muscle cells. The receiver operating characteristic (ROC) curve showed that GSTA4 mean methylation (AUC = .80, p < .001) was a reliable predictor of women intracranial aneurysm, among which CpG 1 exhibited the best predictive value (AUC = .89, p < .001). In addition, GSTA4 expression levels could also predict the risk of IA in women (AUC = .87, p = .005). Conclusion: Decreased DNA methylation and increased mRNA expression of the GSTA4 gene are associated with the risk of IA in women.

Incomplete Kawasaki disease with development of fatal coronary artery thrombosis in a 13-year-old male

Kawasaki disease (KD) is among one of the most common causes of vasculitis in children. Since KD was first described in 1967, there have been several reports of patients who did not meet the full diagnostic criteria for KD but who ultimately developed significant coronary artery lesions. Children with incomplete KD are at similar risk of developing coronary artery abnormalities to those with complete Kawasaki. A previously healthy 13-year-old Asian male was seen at a clinic for fever, pharyngitis, and conjunctivitis. He was given antibiotics for a presumed streptococcal pharyngitis. Two weeks later, the decedent complained of chest pain, collapsed, and was transported by Emergency Medical Services to a nearby hospital where he was pronounced deceased on arrival. A complete autopsy was done by the local medical examiner. Histologically, all three coronary arteries showed varying degrees of severe transmural lymphoplasmacytic inflammation, marked vascular smooth muscle intimal proliferation, focal destruction of muscular and elastic layers, and luminal stenosis. Some vessels had recent thrombi. We present an example of incomplete KD in an older child and reiterate the importance of obtaining relevant medical history in sudden death cases that come to the Medical Examiner Office, especially in the pediatric age group.

Impaired enzymatic reactive aldehyde-detoxifying capacity and glutathione peroxidase activity in the aged human arterial tissue

It is not known whether aging alters the enzymatic reactive aldehyde- and lipid hydroperoxide-detoxifying capacity of the human arterial tissue favoring vascular oxidative stress. To address this issue, we studied the specific enzymatic activities of class 1, 2 and 3 aldehyde dehydrogenase (ALDH1, ALDH2 and ALDH3), glutathione S‑transferase (isozyme A4-4, GSTA4-4) and aldose reductase (AR), namely the major reactive aldehyde-scavenging enzymes, together with the activity of the lipid hydroperoxide-removing enzyme glutathione peroxidase (GSH-Px), in superior thyroid arteries (STA) specimens obtained in the thyroid surgery setting in aged subjects (age 72.3 ± 3.6 years) and young adult controls (age 31.9 ± 3.5 years). Vascular lipid peroxidation was also studied by assessing in STA fluorescent damage products of lipid peroxidation (FDPL), which reflect oxidant-induced 4‑hydroxynonenal and lipid hydroperoxide formation. Remarkably, the activities of ALDH1, ALDH2, ALDH3, GSTA4-4, AR and GSH-Px were significantly lower, and FDPL levels higher, in the arterial tissue of the aged subjects than in that of the young adult controls. Moreover, the enzymatic activities were inversely and significantly correlated with the levels of FDPL in the arterial tissue of both the aged and young subjects, highlighting their vascular antioxidant/antilipoperoxidative role in vivo. Thus, aging impairs the enzymatic reactive aldehyde-detoxifying capacity and GSH-Px activity of the human arterial tissue eventually favoring vascular oxidative stress.

Impaired glutathione-related antioxidant defenses in the arterial tissue of diabetic patients

We studied the specific enzymatic activities of selenium-dependent (GSH-Px) and -independent (GST-Px) glutathione peroxidase, glutathione reductase (GSSG-Red), and glutathione S-transferase (GST) in internal mammary arteries (IMArt) specimens obtained during coronary artery bypass surgery in 18 patients with type 2 diabetes mellitus as compared to 18 non-diabetic controls; vascular lipid peroxidation, namely fluorescent damage products of lipid peroxidation (FDPL) as 4-hydroxynonenal-related oxidative stress indicators, was also studied. Moreover, in other 16 diabetic patients and 16 controls, total glutathione (TGlut) was determined in IMArt specimens specifically homogenized in sulfosalycilic acid to prevent vascular GSH depletion. The activities of GSH-Px, GSSG-Red, and GST were significantly lower, and FDPL levels higher, in the arterial tissue of diabetic patients than in that of controls; GST-Px was undetectable. Such enzymatic activities were inversely correlated with vascular lipid peroxidation, highlighting their antioxidant role in the arterial tissue, as were HbA1c and FDPL levels with the enzymatic activities, suggesting that glycation, oxidant species and lipoperoxidation aldehydes may be involved in glutathione-related enzyme inactivation. Further, in the diabetic patients HbA1c was correlated directly with lipid peroxidation but inversely with TGlut of the arterial tissue. In the patients considered for vascular enzymatic activities and FDPL assay, 3/4-vessel coronary artery disease (CAD) as expression of atherosclerosis severity was present in 9 diabetic patients and in 3 controls. Notably, vascular glutathione-related enzymatic activities were significantly lower, and FDPL levels higher, in the 9 diabetic patients with 3/4-vessel CAD than in the 9 without, as well as in the total of 12 patients with 3/4-vessel CAD than in the total of 24 patients without. Moreover, vascular TGlut content was significantly lower in the diabetic than in the control patients. Three/4-vessel CAD was present in 6 diabetic patients and in 2 controls considered for determination of vascular Tglut content, which was significantly lower in the diabetic patients with 3/4-vessel CAD than in those without, as well in the total of 8 patients with 3/4-vessel CAD than in the total of 24 patients without. Thus, weakened glutathione-related antioxidant capacity and oxidative stress of the arterial tissue are associated with the severity of atherosclerosis. In conclusion, impaired glutathione-related antioxidant defenses of the arterial tissue occur in diabetic patients, eventually favoring vascular oxidative stress and the severity of atherosclerosis.

Reduced Expression of Glutathione S-Transferase 4 Promotes Vascular Neointimal Hyperplasia in CKD

Neointima formation is the leading cause of arteriovenous fistula (AVF) failure. We have shown that CKD accelerates this process by transforming the vascular smooth muscle cells (SMCs) lining the AVF from a contractile to the synthetic phenotype. However, the underlying mechanisms affecting this transformation are not clear. Previous studies have shown that the α-class glutathione transferase isozymes have an important role in regulating 4-hydroxynonenal (4-HNE)-mediated proliferative signaling of cells. Here, using both the loss- and gain-of-function approaches, we investigated the role of glutathione S-transferase α4 (GSTA4) in modulating cellular 4-HNE levels for the transformation and proliferation of SMCs. Compared with non-CKD controls, mice with CKD had downregulated expression of GSTA4 at the mRNA and protein levels, with concomitant increase in 4-HNE in arteries and veins. This effect was associated with upregulated phosphorylation of MAPK signaling pathway proteins in proliferating SMCs. Overexpressing GSTA4 blocked 4-HNE-induced SMC proliferation. Additionally, inhibitors of MAPK signaling inhibited the 4-HNE-induced responses. Compared with wild-type mice, mice lacking GSTA4 exhibited increased CKD-induced neointima formation in AVF. Transient expression of an activated form of GSTA4, achieved using a combined Tet-On/Cre induction system in mice, lowered levels of 4-HNE and reduced the proliferation of SMCs. Together, these results demonstrate the critical role of GSTA4 in blocking CKD-induced neointima formation and AVF failure.

Mechanism of the protective effects of the combined treatment with rhynchophylla total alkaloids and sinapine thiocyanate against a prothrombotic state caused by vascular endothelial cell inflammatory damage

The aim of the present study was to investigate the effect and the underlying mechanism of the combined treatment of rhynchophylla total alkaloids (RTA) and sinapine thiocyanate for protection against a prothrombotic state (PTS) associated with the tumor necrosis factor-alpha (TNF-α)-induced inflammatory injury of vascular endothelial cells (VECs). A TNF-α-induced VEC inflammatory injury model was established, and cell morphology of VECs was evaluated using scanning electron microscopy. In addition, reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to examine the mRNA and protein expression of coagulation-related factors, including nuclear factor-κB (NF-κB), transforming growth factor-β1 (TGF-β1), tissue factor (TF), plasminogen activator inhibitor (PAI-1), protease-activation receptors (PAR-1) and protein kinase C (PKC-α) in VECs. Combined treatment with RTA and sinapine thiocyanate was demonstrated to reduce, to a varying extent, the mRNA and protein expression of NF-κB, TGF-β1, TF, PAR-1, PKC-α and PAI-1. Furthermore, combined treatment with RTA and sinapine thiocyanate was able to downregulate the expression of coagulation-related factors in injured VECs, thereby inhibiting the PTS induced by vascular endothelial injury. The underlying mechanism is partially associated with the TF-mediated activation of the thrombin-receptor signaling pathway that suppresses coagulation during inflammation and balances fibrinolysis in order to inhibit fibrin generation and deposition.

Leukemia Inhibitory Factor and Fibroblast Growth Factor 2 Critically and Mutually Sustain Pluripotency of Rabbit Embryonic Stem Cells

Effects of leukemia inhibitory factor (LIF) and fibroblast growth factor 2 (FGF2) on establishment and maintenance of rabbit embryonic stem cell (rESC) lines were assessed. When grown on MEF feeders, rESC lines derived from fertilized embryos were established and maintained in medium containing paracrine factors LIF (via STAT3) and/or FGF2 (via MEK-ERK1/2 and PI3K-AKT). However, high levels of ERK1/2 and AKT activities in rESCs were crucial for maintaining their undifferentiated proliferation. Although rESCs under the influence of either LIF (500, 1,000, and 2,000 U/ml) or FGF2 (5, 10, and 20 ng/ml) alone had enhanced expression of pluripotency markers, peak expression occurred when both LIF (1,000 U/ml) and FGF2 (10 ng/ml) were applied. Induced dephosphorylation of STAT3, ERK1/2, and AKT by specific inhibitors limited growth of rESCs and caused remarkable losses of self-renewal capacity; therefore, we inferred that STAT3, ERK, and AKT had essential roles in maintaining rESC proliferation and self-renewal. We concluded that LIF and FGF2 jointly maintained the undifferentiated state and self-renewal of rESCs through an integrative signaling module.

Novel random peptide libraries displayed on AAV serotype 9 for selection of endothelial cell-directed gene transfer vectors

We have demonstrated the potential of random peptide libraries displayed on adeno-associated virus (AAV)2 to select for AAV2 vectors with improved efficiency for cell type-directed gene transfer. AAV9, however, may have advantages over AAV2 because of a lower prevalence of neutralizing antibodies in humans and more efficient gene transfer in vivo. Here we provide evidence that random peptide libraries can be displayed on AAV9 and can be utilized to select for AAV9 capsids redirected to the cell type of interest. We generated an AAV9 peptide display library, which ensures that the displayed peptides correspond to the packaged genomes and performed four consecutive selection rounds on human coronary artery endothelial cells in vitro. This screening yielded AAV9 library capsids with distinct peptide motifs enabling up to 40-fold improved transduction efficiencies compared with wild-type (wt) AAV9 vectors. Incorporating sequences selected from AAV9 libraries into AAV2 capsids could not increase transduction as efficiently as in the AAV9 context. To analyze the potential on endothelial cells in the intact natural vascular context, human umbilical veins were incubated with the selected AAV in situ and endothelial cells were isolated. Fluorescence-activated cell sorting analysis revealed a 200-fold improved transduction efficiency compared with wt AAV9 vectors. Furthermore, AAV9 vectors with targeting sequences selected from AAV9 libraries revealed an increased transduction efficiency in the presence of human intravenous immunoglobulins, suggesting a reduced immunogenicity. We conclude that our novel AAV9 peptide library is functional and can be used to select for vectors for future preclinical and clinical gene transfer applications.