DJ-1 Alleviates Angiotensin II-Induced Endothelial Progenitor Cell Damage by Activating the PPARγ/HO-1 Pathway

Syndecan-1, an indicator of endothelial glycocalyx degradation, predicts outcome of patients admitted to an ICU with COVID-19

Background

We investigated the feasibility of two biomarkers of endothelial damage (Syndecan-1 and thrombomodulin) in coronavirus disease 2019 (COVID-19), and their association with inflammation, coagulopathy, and mortality.

Methods

The records of 49 COVID-19 patients who were admitted to an intensive care unit (ICU) in Wuhan, China between February and April 2020 were examined. Demographic, clinical, and laboratory data, and outcomes were compared between survivors and non-survivors COVID-19 patients, and between patients with high and low serum Syndecan-1 levels. The dynamics of serum Syndecan-1 levels were also analyzed.

Results

The levels of Syndecan-1 were significantly higher in non-survivor group compared with survivor group (median 1031.4 versus 504.0 ng/mL, P = 0.002), and the levels of thrombomodulin were not significantly different between these two groups (median 4534.0 versus 3780.0 ng/mL, P = 0.070). Kaplan–Meier survival analysis showed that the group with high Syndecan-1 levels had worse overall survival (log-rank test: P = 0.023). Patients with high Syndecan-1 levels also had significantly higher levels of thrombomodulin, interleukin-6, and tumor necrosis factor-α. Data on the dynamics of Syndecan-1 levels indicated much greater variations in non-survivors than survivors.

Conclusions

COVID-19 patients with high levels of Syndecan-1 develop more serious endothelial damage and inflammatory reactions, and have increased mortality. Syndecan-1 has potential for use as a marker for progression or severity of COVID-19. Protecting the glycocalyx from destruction is a potential treatment for COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00412-1.

Remifentanil Suppresses Oxidative Stress and Inflammation Induced by Glutamate via Activation of PPARγ/HO-1 Signaling Pathway in Hippocampal Neuronal Cells

Excitotoxicity caused by glutamate severely damages the central nervous system, contributing to the progress of neurodegenerative diseases. Remifentanil is an ultra-short acting synthetic α-opioid receptor agonist and it protects the body against oxidative stress. Oxidative stress is a causative factor for neuronal cell death, contributing to the pathogenesis of neurological diseases. More importantly, remifentanil has been confirmed to have neuroprotective effects on cerebral ischemia. Hence, the aim of the present study was to investigate the molecular mechanism underlying the effect of remifentanil on glutamate (Glu)-induced oxidative stress and inflammation in hippocampal cells. In present study, the cell viability was detected via CCk-8 assay. The cell apoptosis was evaluated by tunel assay. Western blot was performed for measurement of protein expression level. Generation of ROS level was detected by the ROS Activity Assay Kit (KA3842, Abnova) and DCF-DA staining method. MDA and SOD levels were detected by corresponding kits. The results from the present study suggested that remifentanil enhanced cell viability, reduced cell apoptosis rate and prevented oxidative stress in glutamate-induced HT22 cells. The PPARγ/HO-1 pathway was activated by remifentanil. After inhibition of PPARγ/HO-1 pathway, the anti-apoptosis and anti-oxidative stress effects of remifentanil were abolished. In conclusion, remifentanil has anti-apoptosis and anti-oxidative stress effects on glutamate-induced HT22 Cells via PPARγ/HO-1 pathway. Hence, remifentanil is a promising agent for attenuation of cytotoxicity induced by glutamate, providing a new strategy for treatment of excitotoxicity caused by glutamate in the central nervous system.

DJ-1 activates the noncanonical NF-κB pathway via interaction with Cezanne to inhibit the apoptosis and promote the proliferation of Ishikawa cells

BACKGROUND

Endometrial cancer is generally one of the most evident malignant tumours of the female reproductive system, and the mechanisms underlying its cell proliferation and apoptosis are key to research in gynaecological oncology. In the paper, the in-depth molecular mechanism by which DJ-1 protein regulates the proliferation and apoptosis of Ishikawa cells was investigated.

METHODS AND RESULTS

DJ-1 knockdown and overexpressing Ishikawa stable cell lines were established by lentiviral transduction. The levels of DJ-1 and noncanonical NF-κB signaling key proteins were evaluated by Western blotting. Cell counting kit-8 (CCK-8) and flow cytometry were applied to analyze the cell viability and apoptosis. Co-immunoprecipitation experiment was utilized to assess the DJ-1-Cezanne interaction. The results showed that DJ-1 overexpression conferred apoptosis resistance and high proliferation on Ishikawa cells, while DJ-1 knockdown in Ishikawa cells produced the opposite results. These findings again suggested that DJ-1 inhibits the apoptosis and promotes the proliferation of Ishikawa cells. More crucially, further data showed that the noncanonical NF-κB activation was required for the regulation of Ishikawa cell proliferation and apoptosis by DJ-1. Meanwhile, it was found that noncanonical NF-κB pathway may be activated by DJ-1 interacting with and negatively regulating Cezanne in Ishikawa cells.

CONCLUSIONS

Overall, this work revealed that DJ-1 associates with and negatively regulates Cezanne and consequently triggers the noncanonical NF-κB activation, thereby regulating Ishikawa cell proliferation and apoptosis.

Sesn2 attenuates the damage of endothelial progenitor cells induced by angiotensin II through regulating the Keap1/Nrf2 signal pathway

Endothelial progenitor cell (EPC) dysfunction is an important physiopathological mechanism in the dynamics of the formation of atherosclerosis. It has been reported that angiotensin II (Ang-II) damages the function of EPCs in atherosclerotic plaque through induction of oxidative stress. Sestrin 2 (Sesn2) serves as an antioxidant role in oxidative stress, however, the exact mechanisms underlying the dynamics of how Sesn2 may factor into EPCs after Ang-II treatments needs to be illustrated. We isolated EPCs from human umbilical cord blood samples and treated with Ang-II. Western blotting, qRT-PCR, transwell assays, immunofluorescence and so on were used to investigate the mechanisms underlying the roles of Sesn2 in EPCs treated with Ang-II. Ang-II was found to promote the apoptosis of EPCs as well as inhibited the mRNA and protein expression of Sesn2. Upregulation of Sesn2 attenuated the negative effect of Ang-II. Sesn2 increased the protein expression of Nrf2 by enhancing P62-dependent autophagy. Silencing of Nrf2 enhanced the degree of apoptosis of EPCs as well as resulted in the impairment of EPC functions through inducing the promotion of (reactive oxygen species) ROS production. Our study results indicated that Sesn2 facilitated the viability of EPCs After treatment with Ang-II, as well as provided a potential therapeutic target to alleviate the progression of atherosclerosis.

Machine learning discriminates a movement disorder in a zebrafish model of Parkinson's disease

Animal models of human disease provide an in vivo system that can reveal molecular mechanisms by which mutations cause pathology, and, moreover, have the potential to provide a valuable tool for drug development. Here, we have developed a zebrafish model of Parkinson's disease (PD) together with a novel method to screen for movement disorders in adult fish, pioneering a more efficient drug-testing route. Mutation of the PARK7 gene (which encodes DJ-1) is known to cause monogenic autosomal recessive PD in humans, and, using CRISPR/Cas9 gene editing, we generated a Dj-1 loss-of-function zebrafish with molecular hallmarks of PD. To establish whether there is a human-relevant parkinsonian phenotype in our model, we adapted proven tools used to diagnose PD in clinics and developed a novel and unbiased computational method to classify movement disorders in adult zebrafish. Using high-resolution video capture and machine learning, we extracted novel features of movement from continuous data streams and used an evolutionary algorithm to classify parkinsonian fish. This method will be widely applicable for assessing zebrafish models of human motor diseases and provide a valuable asset for the therapeutics pipeline. In addition, interrogation of RNA-seq data indicate metabolic reprogramming of brains in the absence of Dj-1, adding to growing evidence that disruption of bioenergetics is a key feature of neurodegeneration.This article has an associated First Person interview with the first author of the paper.

Angiotensin II-induced superoxide and decreased glutathione in proximal tubules: effect of dietary fructose

Angiotensin II exacerbates oxidative stress in part by increasing superoxide (O2-) production by many renal tissues. However, whether it does so in proximal tubules and the source of O2- in this segment are unknown. Dietary fructose enhances the stimulatory effect of angiotensin II on proximal tubule Na⁺ reabsorption, but whether this is true for oxidative stress is unknown. We hypothesized that angiotensin II causes proximal nephron oxidative stress in part by stimulating NADPH oxidase (NOX)4-dependent O2- production and decreasing the amount of the antioxidant glutathione, and this is exacerbated by dietary fructose. We measured basal and angiotensin II-stimulated O2- production with and without inhibitors, NOX1 and NOX4 expression, and total and reduced glutathione (GSH) in proximal tubules from rats drinking either tap water (control) or 20% fructose. Angiotensin II (10 nM) increased O2- production by 113 ± 42 relative light units·mg protein^-1·s^-1 in controls and 401 ± 74 relative light units·mg protein^-1·s^-1 with 20% fructose (n = 11 for each group, P < 0.05 vs. control). Apocynin and the Nox1/4 inhibitor GKT136901 prevented angiotensin II-induced increases in both groups. NOX4 expression was not different between groups. NOX1 expression was undetectable. Angiotensin II decreased GSH by 1.8 ± 0.8 nmol/mg protein in controls and by 4.2 ± 0.9 nmol/mg protein with 20% fructose (n = 18 for each group, P < 0.047 vs. control). We conclude that 1) angiotensin II causes oxidative stress in proximal tubules by increasing O2- production by NOX4 and decreasing GSH and 2) dietary fructose enhances the ability of angiotensin II to stimulate O2- and diminish GSH, thereby exacerbating oxidative stress in this segment.

Emerging Role of Vitamin D and its Associated Molecules in Pathways Related to Pathogenesis of Thrombosis

Vitamin D, besides having an essential role in calcium and bone metabolism, also acts as a mediator of many non-calcemic effects through modulations of several biological responses. Vitamin D exists in its two major forms, vitamin D₂, or commonly known as ergocalciferol, and vitamin D₃, or commonly known as cholecalciferol. Both of these forms bind to vitamin D-binding protein to get transported to all vital target organs, where it serves as a natural ligand to vitamin D receptors for enabling their biological actions. Clinical reports corroborating vitamin D deficiency with an increase in thrombotic episodes implicate the role of vitamin D and its associated molecule in the regulation of thrombosis-related pathways. Thrombosis is the formation and propagation of a blood clot, known as thrombus. It can occur either in the arterial or the venous system resulting in many severe complications, including myocardial infarction, stroke, ischemia, and venous thromboembolism. Vitamin D, directly or indirectly, controls the expression of several genes responsible for the regulation of cellular proliferation, differentiation, apoptosis, and angiogenesis. All of these are the processes of potential relevance to thrombotic disorders. This review, thus, discussed the effects of vitamin D on pathways involved in thrombosis, such as hemostatic process, inflammatory pathway, and endothelial cell activation, with a focus on the molecular mechanisms associated with them.

LncRNA AK094457 promotes AngII-mediated hypertension and endothelial dysfunction through suppressing of activation of PPARγ

Hypertension is one of the major risk factors for cardiovascular disease worldwide and is striking more young people, which is characterized by impaired vascular endothelial function. To find the functional lncRNAs associated with hypertension, high throughput lncRNA microarray were used to analyze expression profile of the lncRNAs in the aortic vascular endothelial cells (VECs) of spontaneously hypertensive rats (SHRs). The tail vein injection of siRNA was used to study the influence of lncRNA AK094457 inhibition on endothelial function in vivo. In vitro, endothelial function was studied in endothelial cells transfected with lncRNA AK094457-overexpressed vectors and siRNAs. pPPARγ and iNOS protein levels were detected with Western blot. Elisa assay was used to analyze the secretion of AngII, ET-1, ROS and LDH level. The nitrite/nitrate (NO₂^-/NO₃^-) concentration was measured using a colorimetric assay. LncRNA AK094457 was a most upregulated lncRNA in SHRs. It is showed that downregulation of AK094457 significantly reduced rat arterial pressure, increased activation of endothelial PPARγ, and suppressed serum contents of AngII and NO in vivo. Furthermore, results from gain-and-loss of function in primary aortic endothelial cells indicated that AK094457 negatively regulated activation of PPARγ and promoted AngII-mediated endothelial dysfunction, manifested by decreased capacities of cell proliferation and migration, and increased levels of ROS production and LDH release. In conclusion, lncRNA AK094457 is identified as a key regulator in blood pressure and endothelial function, which can increase AngII-induced hypertension and endothelial dysfunction via suppression of PPARγ.

Inhibition of Mitochondrial Oxidative Damage Improves Reendothelialization Capacity of Endothelial Progenitor Cells via SIRT3 (Sirtuin 3)-Enhanced SOD2 (Superoxide Dismutase 2) Deacetylation in Hypertension

OBJECTIVE

Dysfunction of endothelial progenitor cells (EPCs) leads to impaired endothelial repair capacity in patients with hypertension, but the mechanisms remain incompletely understood. Mitochondrial oxidative stress is involved in endothelial injury in hypertension. In this study, we aim to investigate the role of mitochondrial oxidative stress in the deficient endothelial reparative capacity of EPCs and identify enhanced SIRT3 (sirtuin 3)-mediated SOD2 (superoxide dismutase 2) deacetylation as a novel endothelial protective mechanism in hypertension. Approach and Results: Hypertension-EPCs displayed increased mitochondrial reactive oxygen species and mitochondrial damage, including loss of mitochondrial membrane potential, abnormal mitochondrial ultrastructure, and mtDNA oxidative injury, which was coincided with impaired in vitro function and in vivo reendothelialization capacity. The harmful effects of hypertension on mitochondrial function of EPCs were in vitro mimicked by angiotensin II coincubation. Scavenging of mitochondrial reactive oxygen species with mitoTEMPO attenuated mitochondrial oxidative damage and rescued reendothelialization capacity. Enzymatic activity and deacetylation level of SOD2 were significantly reduced in hypertension-EPCs, which was accompanied with decreased SIRT3 expression. Knockdown of SIRT3 in EPCs resulted in mitochondrial oxidative damage, hyperacetylation of SOD2, and suppression of reendothelialization capacity. SIRT3 physically interacted with SOD2 and eliminated excess mitochondrial reactive oxygen species, restored mitochondrial function through enhancing SOD2 activity by deacetylation of K68. Upregulation of SIRT3/SOD2 signaling improved reendothelialization capability of EPCs.

CONCLUSIONS

The present study demonstrated for the first time that mitochondrial oxidative damage because of deficient SIRT3/SOD2 signaling contributes to the decline in reendothelialization capacity of EPCs in hypertension. Maintenance of mitochondrial redox homeostasis in EPCs may be a novel therapeutic target for endothelial injury.

The Nuclear Export and Ubiquitin-Proteasome-Dependent Degradation of PPARγ Induced By Angiotensin II

Evidence has documented local angiotensin II (Ang II) as a pro-oxidant and pro-inflammatory molecule contributes to progressive deterioration of organ function in diseases. Peroxisome proliferator-activated receptor γ (PPARγ), a ligand-activated transcription factor, plays crucial roles in protection against oxidative stress and inflammation. Ang II stimulation decreases PPARγ protein in multiple types of cells, while the regulatory role of Ang II on PPARγ is not clear. Here we show that Ang II down-regulated PPARγ in ECV304 cells through 2 actions, inducing nuclear export and loss of protein. The nuclear export of PPARγ occurred transiently in the early phase, while the reduction in PPARγ protein happened in the later phase and was more persistent. Both alterations in PPARγ were accompanied by the decrease in PPARγ-DNA binding activity. Reduction of PPARγ protein levels was also coupled with the inhibition of PPARγ target genes. In addition, activation of PPARγ by its ligand troglitazone could completely counteract both 2 actions of Ang II on PPARγ. Further studies demonstrated that the decline of PPARγ protein was in association with ubiquitin-proteasome-dependent degradation, which was supported by the increase in polyubiquitin-PPARγ conjugates and the inhibitory effect of lactacystin, a specific proteasome inhibitor, on the loss of PPARγ. Taken together, this study uncovers a novel means by which Ang II down-regulates PPARγ. This down-regulation disrupts nuclear PPARγ function, which may lead to the loss of beneficial effects of PPARγ in response to Ang II stress.

Angiotensin II Attenuates the Bioactivities of Human Endothelial Progenitor Cells via Downregulation of β2-Adrenergic Receptor

Cross talks between the renin-angiotensin system (RAS), sympathetic nervous system, and vascular homeostasis are tightly coordinated in hypertension. Angiotensin II (Ang II), a key factor in RAS, when abnormally activated, affects the number and bioactivity of circulating human endothelial progenitor cells (hEPCs) in hypertensive patients. In this study, we investigated how the augmentation of Ang II regulates adrenergic receptor-mediated signaling and angiogenic bioactivities of hEPCs. Interestingly, the short-term treatment of hEPCs with Ang II drastically attenuated the expression of beta-2 adrenergic receptor (ADRB2), but did not alter the expression of beta-1 adrenergic receptor (ADRB1) and Ang II type 1 receptor (AT1R). EPC functional assay clearly demonstrated that the treatment with ADRB2 agonists significantly increased EPC bioactivities including cell proliferation, migration, and tube formation abilities. However, EPC bioactivities were decreased dramatically when treated with Ang II. Importantly, the attenuation of EPC bioactivities by Ang II was restored by treatment with an AT1R antagonist (telmisartan; TERT). We found that AT1R binds to ADRB2 in physiological conditions, but this binding is significantly decreased in the presence of Ang II. Furthermore, TERT, an Ang II-AT1R interaction blocker, restored the interaction between AT1R and ADRB2, suggesting that Ang II might induce the dysfunction of EPCs via downregulation of ADRB2, and an AT1R blocker could prevent Ang II-mediated ADRB2 depletion in EPCs. Taken together, our report provides novel insights into potential therapeutic approaches for hypertension-related cardiovascular diseases.

Apelin/APJ system: A novel promising target for anti-aging intervention

Apelin, an endogenous ligand for the G protein-coupled receptor APJ, is widely expressed in various organs. Recent research has indicated that the Apelin/APJ system plays an important role in aging. Apelin and APJ receptor expression are down-regulated with increasing age. In murine models, Apelin and APJ knockouts exhibit accelerated senescence whereas Apelin-restoration results in enhanced vigor and rejuvenated behavioral and circadian phenotypes. Furthermore, aged Apelin knockout mice develop progressive impairment of cardiac contractility associated with systolic dysfunction. Apelin is crucial to maintain cardiac contractility in aging. Moreover, the Apelin/APJ system appears to be involved in regulation of renin-angiotensin-aldosterone system (RAAS), apoptosis, inflammation and oxidative stress which promotes aging. Likewise, the Apelin/APJ system regulates autophagy, stem cells and the sirtuin family thus contributing to anti-aging. In this review, we describe the relationship between Apelin/APJ system and aging. We elaborate on the role of the Apelin/APJ system in aging stimulators, aging inhibitors and age-related diseases such as obesity, diabetes and cardiovascular disease. We conclude that Apelin/APJ system might become a novel promising therapeutic target for anti-aging.

Puerarin protects endothelial progenitor cells from damage of angiotensin II via activation of ERK1/2‑Nrf2 signaling pathway

Endothelial progenitor cell (EPC) dysfunction is associated with the formation of carotid atherosclerosis. It has been demonstrated that angiotensin II (Ang II) may impair the function of EPCs and puerarin, a natural product, possesses cardiovascular protective effects against oxidative stress and inflammation. Therefore, the present study aimed to investigate the beneficial effects of puerarin in Ang II‑induced EPC injury, and to elucidate the underlying mechanisms. Treatment with Ang II suppressed EPC proliferation and migration, increased the expression of the senescence marker β‑galactosidase, and the adhesion molecules intracellular adhesion molecule‑1 and vascular cell adhesion molecule‑1. However, the above effects were markedly alleviated by treatment with puerarin in a dose‑dependent manner (1, 10 and 100 µM). In addition, Ang II significantly increased reactive oxygen species production and the levels of the inflammatory cytokine tumor necrosis factor‑α and interleukin‑6. Notably, these effects were reversed by puerarin. However, it was identified that the impaired EPC functions were due to inhibition of the phosphorylation of extracellular signal‑regulated kinase 1 and 2 (ERK1/2) and the degradation of nuclear factor erythroid 2 like 2 (Nrf2), and treatment with puerarin activated the ERK1/2‑Nrf2 signaling pathway. The results of the present study indicated that puerarin protected Ang II‑induced EPC dysfunction via activation of the ERK1/2‑Nrf2 signaling pathway.