Endothelin-1 Downregulates Sulfur Dioxide/Aspartate Aminotransferase Pathway via Reactive Oxygen Species to Promote the Proliferation and Migration of Vascular Smooth Muscle Cells

Interdialytic home systolic blood pressure variability increases all-cause mortality in hemodialysis patients

BACKGROUND

The association between Interdialytic home blood pressure variability (BPV) and the prognosis of patients undergoing maintenance hemodialysis (MHD) largely unknown.

HYPOTHESIS

We proposed the hypothesis that interdialytic home BPV exert effect on cardiac and all-cause mortality among individuals undergoing MHD.

METHODS

A total of 158 patients receiving MHD at the hemodialysis unit of Wuhan Fourth Hospital between December 2019 and August 2020 were included in this prospective cohort study. Patients were divided into tertiles according to the systolic BPV (SBPV), and the primary endpoints were cardiac and all-cause death. Kaplan-Meier analysis was used to assess the relationship between long-term survival and interdialytic home SBPV. In addition, Cox proportional hazards regression models were used to identify risk factors contributing to poor prognosis.

RESULTS

The risk of cardiac death and all-cause death was gradually increased in patients according to tertiles of SBPV (3.5% vs. 14.8% vs. 19.2%, p for trend = .021; and 11.5% vs. 27.8% vs. 44.2%, p for trend <.001). The Cox regression analysis revealed that compared to Tertile 1, the hazard ratios for all-cause mortality in Tertile 2 and Tertile 3 were 3.13 (p = .026) and 3.24 (p = .021), respectively, after adjustment for a series of covariates.

CONCLUSIONS

The findings revealed a positive correlation between increased interdialytic home SBPV and elevated mortality risk in patients with MHD.

Changes in glutamic oxaloacetic transaminase 2 during rat physiological and pathological cardiomyocyte hypertrophy

BACKGROUND

Physiological and pathological cardiomyocyte hypertrophy are important pathophysiological processes of adult congenital heart disease-associated ventricular hypertrophy. Glutamic oxaloacetic transaminase (GOT) is a vital marker of myocardial injury. This study aimed to investigate the changes in GOT levels during physiological and pathological cardiomyocyte hypertrophy in rats.

METHODS

RNA-seq analysis and colorimetric methods were used to evaluate the changes in GOT mRNA and activity, respectively. GOT2 protein expression was detected by western blotting and immunofluorescence. Hematoxylin-eosin and wheat germ agglutinin methods were used to observe changes in rat cardiomyocyte morphology.

RESULTS

In juvenile rat hearts, GOT mRNA expression and activity, and GOT2 protein level increased with age-related physiological cardiomyocyte hypertrophy; however, GOT2 protein level was reduced in hypoxia-induced pathological cardiomyocyte hypertrophy.

CONCLUSIONS

GOT2 may regulate physiological and pathological myocardial hypertrophy in rats. We speculated that the low GOT2 level contributed to the rapid occurrence of pathological cardiomyocyte hypertrophy, causing strong plasticity of right ventricular cardiomyocytes in the early postnatal period and heart failure in adulthood.

NLRP3 inflammasome involves in the pathophysiology of sepsis-induced myocardial dysfunction by multiple mechanisms

Sepsis-induced myocardial dysfunction (SIMD) is one of the serious health-affecting problems worldwide. At present, the mechanisms of SIMD are still not clearly elucidated. The NOD-like receptor protein 3 (NLRP3) inflammasome has been assumed to be involved in the pathophysiology of SIMD by regulating multiple biological processes. NLRP3 inflammasome and its related signaling pathways might affect the regulation of inflammation, autophagy, apoptosis, and pyroptosis in SIMD. A few molecular specific inhibitors of NLRP3 inflammasome (e.g., Melatonin, Ulinastatin, Irisin, Nifuroxazide, and Ginsenoside Rg1, etc.) have been developed, which showed a promising anti-inflammatory effect in a cellular or animal model of SIMD. These experimental findings indicated that NLRP3 inflammasome could be a promising therapeutic target for SIMD treatment. However, the clinical translation of NLRP3 inhibitors for treating SIMD still requires robust in vivo and preclinical trials.

Advances in the research of sulfur dioxide and pulmonary hypertension

Pulmonary hypertension (PH) is a fatal disease caused by progressive pulmonary vascular remodeling (PVR). Currently, the mechanisms underlying the occurrence and progression of PVR remain unclear, and effective therapeutic approaches to reverse PVR and PH are lacking. Since the beginning of the 21st century, the endogenous sulfur dioxide (SO2)/aspartate transaminase system has emerged as a novel research focus in the fields of PH and PVR. As a gaseous signaling molecule, SO2 metabolism is tightly regulated in the pulmonary vasculature and is associated with the development of PH as it is involved in the regulation of pathological and physiological activities, such as pulmonary vascular cellular inflammation, proliferation and collagen metabolism, to exert a protective effect against PH. In this review, we present an overview of the studies conducted to date that have provided a theoretical basis for the development of SO2-related drug to inhibit or reverse PVR and effectively treat PH-related diseases.

Emerging role of metabolic reprogramming in hyperoxia-associated neonatal diseases

Oxygen therapy is common during the neonatal period to improve survival, but it can increase the risk of oxygen toxicity. Hyperoxia can damage multiple organs and systems in newborns, commonly causing lung conditions such as bronchopulmonary dysplasia and pulmonary hypertension, as well as damage to other organs, including the brain, gut, and eyes. These conditions are collectively referred to as newborn oxygen radical disease to indicate the multi-system damage caused by hyperoxia. Hyperoxia can also lead to changes in metabolic pathways and the production of abnormal metabolites through a process called metabolic reprogramming. Currently, some studies have analyzed the mechanism of metabolic reprogramming induced by hyperoxia. The focus has been on mitochondrial oxidative stress, mitochondrial dynamics, and multi-organ interactions, such as the lung-gut, lung-brain, and brain-gut axes. In this article, we provide an overview of the major metabolic pathway changes reported in hyperoxia-associated neonatal diseases and explore the potential mechanisms of metabolic reprogramming. Metabolic reprogramming induced by hyperoxia can cause multi-organ metabolic disorders in newborns, including abnormal glucose, lipid, and amino acid metabolism. Moreover, abnormal metabolites may predict the occurrence of disease, suggesting their potential as therapeutic targets. Although the mechanism of metabolic reprogramming caused by hyperoxia requires further elucidation, mitochondria and the gut-lung-brain axis may play a key role in metabolic reprogramming.

Role of ryanodine receptor 2 and FK506-binding protein 12.6 dissociation in pulmonary hypertension

Pulmonary hypertension (PH) is a devastating disease characterized by a progressive increase in pulmonary arterial pressure leading to right ventricular failure and death. A major cellular response in this disease is the contraction of smooth muscle cells (SMCs) of the pulmonary vasculature. Cell contraction is determined by the increase in intracellular Ca2+ concentration ([Ca2+]i), which is generated and regulated by various ion channels. Several studies by us and others have shown that ryanodine receptor 2 (RyR2), a Ca2+-releasing channel in the sarcoplasmic reticulum (SR), is an essential ion channel for the control of [Ca2+]i in pulmonary artery SMCs (PASMCs), thereby mediating the sustained vasoconstriction seen in PH. FK506-binding protein 12.6 (FKBP12.6) strongly associates with RyR2 to stabilize its functional activity. FKBP12.6 can be dissociated from RyR2 by a hypoxic stimulus to increase channel function and Ca2+ release, leading to pulmonary vasoconstriction and PH. More specifically, dissociation of the RyR2-FKBP12.6 complex is a consequence of increased mitochondrial ROS generation mediated by the Rieske iron-sulfur protein (RISP) at the mitochondrial complex III after hypoxia. Overall, RyR2/FKBP12.6 dissociation and the corresponding signaling pathway may be an important factor in the development of PH. Novel drugs and biologics targeting RyR2, FKBP12.6, and related molecules may become unique effective therapeutics for PH.

Guanxinping Tablets Inhibit ET-1-Induced Proliferation and Migration of MOVAS by Suppressing Activated PI3K/Akt/NF-κB Signaling Cascade

Background/Aim

Abnormal proliferation and migration of vascular smooth muscle cells is one of the main causes of atherosclerosis (AS). Therefore, the suppression of abnormal proliferation and migration of smooth muscle cells are the important means for the prevention and inhibition of AS. The clinical effects of Guanxinping (GXP) tablets and preliminary clinical research on the topic have proved that GXP can effectively treat coronary heart disease, but its underlying mechanism remains unclear. This study aimed to confirm the inhibitory effect of GXP on the abnormal proliferation of mouse aortic vascular smooth muscle (MOVAS) cells and to explore the underlying mechanism.

Methods

MOVAS cells were divided into two major groups: physiological and pathological groups. In the physiological group, MOVAS cells were directly stimulated with GXP, whereas in the pathological group, the cells were stimulated by endothelin-1 (ET-1) before intervention by GXP. At the same time, atorvastatin calcium, which effectively inhibits the abnormal proliferation of MOVAS cells, was used in the negative control group. CCK8 assay, scratch test, ELISA, Western blotting, and immunofluorescence staining were performed to observe the proliferation and migration of MOVAS cells and the expression levels of related factors after drug intervention in each group.

Results

In the physiological group, GXP had no significant effect on the proliferation and migration of MOVAS cells and the related factors. In the pathological group, a high dose of GXP reduced the abnormal proliferation and migration of MOVAS cells. Further, it reduced the expression levels of PI3K; inhibited the phosphorylation of Akt (protein kinase B); upregulated IκB-α levels; prevented nuclear factor kappa B (NF-κB) from entering the nucleus; downregulated the expression of interleukin 6 (IL6), IL-1β, and iNOS; and upregulated the ratio of apoptosis-related factor Bax/Bcl-2. There was no significant difference between the high-dose GXP group and the atorvastatin calcium group (negative control group).

Conclusion

Our findings revealed that GXP was able to inhibit the proliferation and migration of MOVAS cells by regulating the PI3K/Akt/NF-κB pathway.

Sulfur Dioxide: Endogenous Generation, Biological Effects, Detection, and Therapeutic Potential

Significance: Previously, sulfur dioxide (SO₂) was recognized as an air pollutant. However, it is found to be endogenously produced in mammalian tissues. As a new gasotransmitter, SO₂ is involved in regulating the structure and function of blood vessels, heart, lung, gastrointestinal tract, nervous system, etc.Recent Advances: Increasing evidence showed that endogenous SO₂ regulates cardiovascular physiological processes, such as blood pressure control, vasodilation, maintenance of the normal vascular structure, and cardiac negative inotropy. Under pathological conditions including hypertension, atherosclerosis, vascular calcification, aging endothelial dysfunction, myocardial injury, myocardial hypertrophy, diabetic myocardial fibrosis, sepsis-induced cardiac dysfunction, pulmonary hypertension, acute lung injury, colitis, epilepsy-related brain injury, depression and anxiety, and addictive drug reward memory consolidation, endogenous SO₂ protects against the pathological changes via different molecular mechanisms and the disturbed SO₂/aspartate aminotransferase pathway is likely involved in the mechanisms for the earlier mentioned pathologic processes. Critical Issues: A comprehensive understanding of the biological effects of endogenous SO₂ is extremely important for the development of novel SO₂ therapy. In this review, we summarized the biological effects, mechanism of action, SO₂ detection methods, and its related prodrugs. Future Directions: Further studies should be conducted to understand the effects of endogenous SO₂ in various physiological and pathophysiological processes and clarify its underlying mechanisms. More efficient and accurate SO₂ detection methods, as well as specific and effective SO₂-releasing systems should be designed for the treatment and prevention of clinical related diseases. The translation from SO₂ basic medical research to its clinical application is also worthy of further study. Antioxid. Redox Signal. 36, 256-274.

Andrographolide Promotes Interaction Between Endothelin-Dependent EDNRA/EDNRB and Myocardin-SRF to Regulate Pathological Vascular Remodeling

Introduction

Pathological vascular remodeling is a hallmark of various vascular diseases. Smooth muscle cell (SMC) phenotypic switching plays a pivotal role during pathological vascular remodeling. The mechanism of how to regulate SMC phenotypic switching still needs to be defined. This study aims to investigate the effect of Andrographolide, a key principle isolated from Andrographis paniculate, on pathological vascular remodeling and its underlying mechanism.

Methods

A C57/BL6 mouse left carotid artery complete ligation model and rat SMCs were used to determine whether Andrographolide is critical in regulating SMC phenotypic switching. Quantitative real-time PCR, a CCK8 cell proliferation assay, BRDU incorporation assay, Boyden chamber migration assay, and spheroid sprouting assay were performed to evaluate whether Andrographolide suppresses SMC proliferation and migration. Immunohistochemistry staining, immunofluorescence staining, and protein co-immunoprecipitation were used to observe the interaction between EDNRA, EDNRB, and Myocardin-SRF.

Results

Andrographolide inhibits neointimal hyperplasia in the left carotid artery complete ligation model. Andrographolide regulates SMC phenotypic switching characterized by suppressing proliferation and migration. Andrographolide activates the endothelin signaling pathway exhibited by dramatically inducing EDNRA and EDNRB expression. The interaction between EDNRA/EDNRB and Myocardin-SRF resulted in promoting SMC differentiation marker gene expression.

Conclusion

Andrographolide plays a critical role in regulating pathological vascular remodeling.

Role of advanced glycation end products on vascular smooth muscle cells under diabetic atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory disease and leading cause of cardiovascular diseases. The progression of AS is a multi-step process leading to high morbidity and mortality. Hyperglycemia, dyslipidemia, advanced glycation end products (AGEs), inflammation and insulin resistance which strictly involved in diabetes are closely related to the pathogenesis of AS. A growing number of studies have linked AGEs to AS. As one of the risk factors of cardiac metabolic diseases, dysfunction of VSMCs plays an important role in AS pathogenesis. AGEs are increased in diabetes, participate in the occurrence and progression of AS through multiple molecular mechanisms of vascular cell injury. As the main functional cells of vascular, vascular smooth muscle cells (VSMCs) play different roles in each stage of atherosclerotic lesions. The interaction between AGEs and receptor for AGEs (RAGE) accelerates AS by affecting the proliferation and migration of VSMCs. In addition, increasing researches have reported that AGEs promote osteogenic transformation and macrophage-like transformation of VSMCs, and affect the progression of AS through other aspects such as autophagy and cell cycle. In this review, we summarize the effect of AGEs on VSMCs in atherosclerotic plaque development and progression. We also discuss the AGEs that link AS and diabetes mellitus, including oxidative stress, inflammation, RAGE ligands, small noncoding RNAs.

β-HB inhibits the apoptosis of high glucose-treated astrocytes via activation of CREB/BDNF axis

OBJECTIVE

Nerve damage can cause severe limb dysfunction and even leave a lifelong disability. The apoptosis of astrocytes may contribute to the nerve damage. In this research, we sought to investigate the effect of β-HB on nerve damage in vitro.

DESIGN

Astrocytes were treated with high glucose (HG) to mimic in vitro model of nerve damage. RT-qPCR and western blot were used to detect expressions of CREB, BDNF, Ki-67, PCNA, Bax, Bcl-2 and cleaved caspase 3 in astrocytes, respectively. MTT was used to measure the cell viability. In addition, flow cytometry was used to detect the cell apoptosis.

RESULTS

β-HB significantly promoted the proliferation and inhibited apoptosis in HG-treated astrocytes. Results showed that of PCNA and Bcl-2 were upregulated, and Bax and cleaved caspase 3 were downregulated after β-HB stimulated in HG-treated astrocytes. In addition, HG-induced inhibition on BDNF expression in astrocytes was notably reversed by β-HB. Furthermore, β-HB promoted the growth and inhibited apoptosis of high glucose-treated astrocytes via activation of CREB/BDNF axis.

CONCLUSION

β-HB promotes the growth and inhibits the apoptosis of high glucose-treated astrocytes via activation of CREB/BDNF axis, which may serve as a new target for treatment of nerve damage.

Effect of sulfur dioxide on vascular biology

Gasotransmitters, such as nitric oxide, carbon monoxide and hydrogen sulfide, can be generated endogenously. These gasotransmitters play important roles in vascular biology, including vasorelaxation and inhibition of vascular smooth muscle cell (VSMC) proliferation. In recent years, sulfur dioxide (SO₂) has been considered as a fourth gasotransmitter. SO₂ is present in air pollution. Moreover, SO₂ toxicity, including oxidative stress and DNA damage, has been extensively reported in previous studies. Recent studies have shown that SO₂ can be endogenously generated in various organs and vascular tissues, where it regulates vascular tone, vascular smooth cell proliferation and collagen synthesis. SO₂ can decrease blood pressure in rats, inhibit smooth muscle cell proliferation and collagen accumulation and promote collagen degradation, and improve vascular remodelling. SO₂ can decrease cardiovascular atherosclerotic plaques by enhancing the antioxidant effect and upregulating nitric oxide/nitric oxide synthase and hydrogen sulfide/cystathionine-γ-lyase pathways. SO₂ can also ameliorate vascular calcification via the transforming growth factor - β1/Smad pathway. The effect of SO₂ on vascular regulation has attracted great interest. SO₂ may be a novel mediator in vascular biology.