Nuclear receptor Nur77 protects against oxidative stress by maintaining mitochondrial homeostasis via regulating mitochondrial fission and mitophagy in smooth muscle cell.

Angiotensin II (AngII) induces disruption of mitochondrial homeostasis and oxidative stress. Nuclear receptor NR4A1 (Nur77) plays an important role in vascular smooth muscle cells (VSMCs) function. However, the role of Nur77 in AngII-induced mitochondrial dynamics and oxidative stress in VSMCs remains unknown. In an in vitro model of AngII-treated cells, we discovered that Nur77 knockout aggravated AngII-induced oxidative stress in VSMCs, whereas activation of Nur77 by celastrol diminished them. Concomitantly, disturbance of mitochondrial dynamics induced by AngII was further exacerbated in Nur77 deficient VSMCs compared to wild-type (WT) VSMCs. Interestingly, Nur77 deletion increased mitochondrial fission but not fusion as evidenced by upregulated fission related genes (Fis1 and Drp1) but not fusion (Opa1 and Mfn2) under AngII stimulation in VSMCs. Mechanically, Nur77 could directly bind to the promoter regions of Fis1 and Drp1 and repress their transcription. Furthermore, we observed that Nur77 additionally promoted mitochondrial homeostasis by increasing mitophagic flux in a transcription-independent manner upon AngII challenge. By using an in vivo model of AngII-induced abdominal aortic aneurysm (AAA), we finally validated the protective role of Nur77 involved in the mitochondrial fission process and mitophagic flux in aortas, which was correlated with the occurrence and development of AAA in AngII-infused mice. Our data defines an essential role of Nur77 in regulating oxidative stress by maintaining mitochondrial homeostasis in VSMCs via both transcription-dependent and transcription-independent manner, supporting the therapeutic potential of Nur77 targeting in vascular diseases.

Macrophage autophagy regulates mitochondria-mediated apoptosis and inhibits necrotic core formation in vulnerable plaques.

The vulnerable plaque is a key distinguishing feature of atherosclerotic lesions that can cause acute atherothrombotic vascular disease. This study was designed to explore the effect of autophagy on mitochondria-mediated macrophage apoptosis and vulnerable plaques. Here, we generated the mouse model of vulnerable carotid plaque in ApoE-/- mice. Application of ApoE-/- mice with rapamycin (an autophagy inducer) inhibited necrotic core formation in vulnerable plaques by decreasing macrophage apoptosis. However, 3-methyladenine (an autophagy inhibitor) promoted plaque vulnerability through deteriorating these indexes. To further explore the mechanism of autophagy on macrophage apoptosis, we used macrophage apoptosis model in vitro and found that 7-ketocholesterol (7-KC, one of the primary oxysterols in oxLDL) caused macrophage apoptosis with concomitant impairment of mitochondria, characterized by the impairment of mitochondrial ultrastructure, cytochrome c release, mitochondrial potential dissipation, mitochondrial fragmentation, excessive ROS generation and both caspase-9 and caspase-3 activation. Interestingly, such mitochondrial apoptotic responses were ameliorated by autophagy activator, but exacerbated by autophagy inhibitor. Finally, we found that MAPK-NF-κB signalling pathway was involved in autophagy modulation of 7-KC-induced macrophage apoptosis. So, we provide strong evidence for the potential therapeutic benefit of macrophage autophagy in regulating mitochondria-mediated apoptosis and inhibiting necrotic core formation in vulnerable plaques.

Atorvastatin ameliorates LPS-induced inflammatory response by autophagy via AKT/mTOR signaling pathway.

Macrophages play crucial roles in immune response and atherosclerosis-related cardiovascular disease. Recent evidence of macrophage autophagy has demonstrated a novel pathway through which contributes to vascular inflammation. The aim of this study was to elucidate the role of autophagy in the inhibition of inflammatory response in macrophages by atorvastatin. We found that atorvastatin promoted autophagy flow determined by up-regulating the expression of autophagy-related protein microtubule-associated protein light chain (LC3B), inducing the formation of autophagosomes and down-regulating the expression of SQSTM1/P62, which is consumed during autophagy. Atorvastatin also inhibited the expression of inflammatory factors IL-1ß and TNFα induced by LPS in RAW264.7 cells. Furthermore, pretreatment with an autophagy inhibitor 3MA or LY294002 attenuated the suppressive effect of atorvastatin on LPS-induced IL-1ß and TNFα expression. Additionally, knockdown autophagy-related gene 5(Atg5) with a special siRNA also prevented the role of atorvastatin in decreasing IL-1ß and TNFα release induced by LPS. Finally, we detected that AKT/mTOR/P70S6K signaling pathway was involved in atorvastatin-induced autophagy in macrophages. These data suggest that atorvastatin attenuates LPS-induced inflammatory factors secretion, at least in part, through enhancing autophagy by AKT/mTOR signaling pathway. Our findings provide a novel evidence that statins exert anti-inflammatory effect in atherosclerosis by autophagy activation.

Efficacy of concurrent chemoradiotherapy with thalidomide and S-1 for esophageal carcinoma and its influence on serum tumor markers.

BACKGROUND: Although the current conventional treatment strategies for esophageal carcinoma (EC) have been proven effective, they are often accompanied by serious adverse events. Therefore, it is still necessary to continue to explore new therapeutic strategies for EC to improve the clinical outcome of patients. AIM: To elucidate the clinical efficacy of concurrent chemoradiotherapy (CCRT) with thalidomide (THAL) and S-1 (tegafur, gimeracil, and oteracil potassium capsules) in the treatment of EC as well as its influence on serum tumor markers (STMs). METHODS: First, 62 patients with EC treated at the Zibo 148 Hospital between November 2019 and November 2022 were selected and grouped according to the received treatment. Among these, 30 patients undergoing CCRT with cis-platinum and 5-fluorouracil were assigned to the control group (Con), and 32 patients receiving CCRT with THAL and S-1 were assigned to the research group (Res). Second, inter-group comparisons were carried out with respect to curative efficacy, incidence of drug toxicities, STMs [carbohydrate antigen 125 (CA125) and macrophage inflammatory protein-3α (MIP-3α)], angiogenesis-related indicators [vascular endothelial growth factor (VEGF); VEGF receptor-1 (VEGFR-1); basic fibroblast growth factor (bFGF); angiogenin-2 (Ang-2)], and quality of life (QoL) [QoL core 30 (QLQ-C30)] after one month of treatment. RESULTS: The analysis showed no statistical difference in the overall response rate and disease control rate between the two patient cohorts; however, the incidences of grade I-II myelosuppression and gastrointestinal reactions were significantly lower in the Res than in the Con. Besides, the post-treatment CA125, MIP-3α, VEGF, VEGFR-1, bFGF, and Ang-2 Levels in the Res were markedly lower compared with the pre-treatment levels and the corresponding post-treatment levels in the Con. Furthermore, more evident improvements in QLQ-C30 scores from the dimensions of physical, role, emotional, and social functions were determined in the Res. CONCLUSION: The above results demonstrate the effectiveness of THAL + S-1 CCRT for EC, which contributes to mild side effects and significant reduction of CA125, MIP-3α, VEGF, VEGFR-1, bFGF, and Ang-2 Levels, thus inhibiting tumors from malignant progression and enhancing patients' QoL.

Association between NLRP3 inflammasome and periprocedural myocardial injury following elective PCI.

Background: Periprocedural myocardial injury (PMI) is a common complication of percutaneous coronary intervention (PCI) associated with poor prognosis. Inflammation has been demonstrated to exert a crucial role in PMI. However, how the inflammation is initiated or sustained in PMI remains elusive. Methods: RNA-seq in peripheral blood mononuclear cells (PBMCs) from 3 Non-PMI and 6 PMI patients was performed with subsequent bioinformatics analysis. RNA-seq results were verified in a patient cohort. We also established the coronary microembolization (CME) mice model to mimic PMI. The activity of caspase-1 in PBMCs was detected by flow cytometry. The levels of interleukin (IL)-1ß, IL-18 and cardiac troponin in plasma were measured by enzyme-linked immunosorbent assay. Results: We identified a total of 901 differentially expressed genes (DEGs) between Non-PMI and PMI patients. These DEGs participated in several inflammation-related processes. NOD-like receptor signaling pathway was significantly enriched in pathway analysis. All the key genes composed in the NLRP3 inflammasome, including NLRP3, PYCARD, CASP1 and IL1B, were upregulated in PMI patients. The activation of NLRP3 inflammasome was then verified by increased activity of caspase-1 in PBMCs, and elevated levels of IL-1ß and IL-18 in plasma in PMI patients. Spearman analysis confirmed tight correlations between caspase-1 activity, IL-1ß, IL-18 levels and troponin T level. In addition, caspase-1 activity, IL-1ß and IL-18 levels were also enhanced in CME mice. Conclusions: We discovered that NLRP3 inflammasome was involved in PMI, thus providing evidence supporting the therapeutic value of NLRP3 inflammasome-targeted strategies in PMI.

Mitochondrial aspartate/glutamate carrier AGC1 regulates cardiac function via Drp1-mediated mitochondrial fission in doxorubicin-induced cardiomyopathy.

Mitochondrial fission has been noted in the pathogenesis of dilated cardiomyopathy (DCM), but the underlying specific regulatory mechanism, especially in the development of doxorubicin (DOX)-induced cardiomyopathy remains unclear. In the present study, we explore whether the aspartate-glutamate carrier1 (AGC1) interacts with the fission protein dynamin-related protein 1 (Drp1) and reveal the functional and molecular mechanisms contributing to DOX-induced cardiomyopathy. Results of co-immunoprecipitation mass spectrometry (CO-IP MS) analysis based on heart tissue of DCM patients revealed that AGC1 expression was significantly upregulated in DCM-induced injury and AGC1 level was closely correlated with mitochondrial morphogenesis and function. We showed that AGC1 knockdown protected mice from DOX-induced cardiomyopathy by preventing mitochondrial fission, while the overexpression of AGC1 in the mouse heart led to impairment of cardiac function. Mechanistically, AGC1 overexpression could upregulate Drp1 expression and contribute to subsequent excessive mitochondrial fission. Specifically, AGC1 knockdown or the use of Drp1-specific inhibitor Mdivi-1 alleviated cardiomyocyte apoptosis and inhibited impairment of mitochondrial function induced by DOX exposure. In summary, our data illustrate that AGC1, as a novel contributor to DCM, regulates cardiac function via Drp1-mediated mitochondrial fission, indicating that targeting AGC1-Drp1 axis could be a potential therapeutic strategy for DOX-induced cardiomyopathy.

Regulating mitochondrial homeostasis and inhibiting inflammatory responses through Celastrol.

Background: The high morbidity and mortality rate of coronary heart disease poses a serious threat to human health. Atherosclerosis, a chronic inflammation of the blood vessel wall, is a significant pathological process leading to coronary heart disease. Macrophage inflammation plays a crucial role in the occurrence and development of atherosclerosis. Methods: Macrophage inflammation model was constructed by lipopolysaccharide (LPS), and macrophages were treated with Celastrol at different concentrations (0, 0.1, 1, 10, 100 ng/mL) and different time points (0, 1, 3, 6, 12 h). Real-time quantitative PCR (qPCR) and Western Blot were used to detect the expression of Nur77 mRNA and protein. Macrophages were then pretreated with 100 nmol/L tripterine for 40min and co-cultured with 100 ng/mL LPS. The expression levels of inflammatory factors and chemokines, phosphorylation of phospho-dynamin-related protein 1 (p-Drp1) at Ser637 and expression of mitochondrial fusion protein mitochondrial fusion protein mitofusin-2 (Mfn2) were detected by qPCR, Western blot and ELISA, respectively. The changes of mitochondrial membrane potential were detected by JC-1 probe. Results: 100 nmol/L Celastrol can significantly inhibit LPS-induced inflammatory responses and down-regulate the expression levels of cytokines such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), tumor necrosis factor-α (TNF-α), chemokines (CCL-2, and CXCL-10), as well as chemokines. And Celastrol could regulate mitochondrial fission and fusion by promoting the phosphorylation of the Drp1 at the Ser637 site, thereby inhibiting mitochondrial fission. At the same time, by up-regulating the level of the Mfn2, Celastrol also promoted mitochondrial fusion. In addition, we found that the nuclear factor-k-gene binding (NF-κB), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 signaling pathways aided the drug's anti-inflammatory effects. We also explored the relationship between Celastrol and the nuclear receptor Nur77 and found that it could up-regulate the expression of Nur77. Conclusions: Our study found that Celastrol could reduce inflammation by regulating Drp1 dependent mitochondrial fission and fusion, as well as the ERK1/2, p38, NF-κB signaling pathways. This finding provides a strong direction for the development of new anti-inflammatory drugs for atherosclerosis.

Nuclear Receptor Nur77 Protects Against Abdominal Aortic Aneurysm by Ameliorating Inflammation Via Suppressing LOX-1.

Background Abdominal aortic aneurysm (AAA) is a life-threatening vascular disorder characterized by chronic inflammation of the aortic wall, which lacks effective pharmacotherapeutic remedies and has an extremely high mortality. Nuclear receptor NR4A1 (Nur77) functions in various chronic inflammatory diseases. However, the influence of Nur77 on AAA has remained unclear. Herein, we sought to determine the effects of Nur77 on the development of AAA. Methods and Results We observed that Nur77 expression decreased significantly in human and mice AAA lesions. Deletion of Nur77 accelerated the development of AAA in mice, as evidenced by increased AAA incidence, abdominal aortic diameters, elastin fragmentation, and collagen content. Consistent with genetic manipulation, pharmacological activation of Nur77 by celastrol showed beneficial effects against AAA. Microscopic and molecular analyses indicated that the detrimental effects of Nur77 deficiency were associated with aggravated macrophage infiltration in AAA lesions and increased pro-inflammatory cytokines secretion and matrix metalloproteinase (MMP-9) expression. Bioinformatics analyses further revealed that LOX-1 was upregulated by Nur77 deficiency and consequently increased the expression of cytokines and MMP-9. Moreover, rescue experiments verified that LOX-1 notably aggravated inflammatory response, an effect that was blunted by Nur77. Conclusions This study firstly demonstrated a crucial role of Nur77 in the formation of AAA by targeting LOX-1, which implicated Nur77 might be a potential therapeutic target for AAA.

Protective Functions of Liver X Receptor α in Established Vulnerable Plaques: Involvement of Regulating Endoplasmic Reticulum-Mediated Macrophage Apoptosis and Efferocytosis.

Background Liver X receptor (LXR) belongs to the metabolic nuclear receptor superfamily, which plays a critical regulatory role in vascular physiology/pathology. However, effects of systemic LXR activation on established vulnerable plaques and the potential isotype-specific role involved remain unclear. Methods and Results The 8-week-old male apolipoprotein E-/- mice went through carotid branch ligation and renal artery constriction, combined with a high-fat diet. Plaques in the left carotid artery acquired vulnerable features 4 weeks later, confirmed by magnetic resonance imaging scans and histological analysis. From that time on, mice were injected intraperitoneally daily with PBS or GW3965 (10 mg/kg per day) for an additional 4 weeks. Treatment with LXR agonists reduced the lesion volume by 52.61%, compared with the vehicle group. More important, a profile of less intraplaque hemorrhage detection and necrotic core formation was found. These actions collectively attenuated the incidence of plaque rupture. Mechanistically, reduced lesional apoptosis, enhanced efferocytosis, and alleviated endoplasmic reticulum stress are involved in the process. Furthermore, genetic ablation of LXRα, but not LXRß, blunted the protective effects of LXR on the endoplasmic reticulum stress-elicited C/EBP-homologous protein pathway in peritoneal macrophages. In concert with the LXRα-predominant role in vitro, activated LXR failed to stabilize vulnerable plaques and correct the acquired cellular anomalies in LXRα-/- apolipoprotein E-/- mice. Conclusions Our results revealed that LXRα mediates the capacity of LXR activation to stabilize vulnerable plaques and prevent plaque rupture via amelioration of macrophage endoplasmic reticulum stress, lesional apoptosis, and defective efferocytosis. These findings might expand the application scenarios of LXR therapeutics for atherosclerosis.

New Thio-Compounds and Monoterpenes With Anti-inflammatory Activities From the Fungus Aspergillus sp. CYH26.

Two new thio-compounds named aspergerthinol A and B (1 and 2) and two new monoterpenes named aspergerthinacids A and B (3 and 4) were isolated from the fungus Aspergillus sp. CYH26 from the rhizosphere soil of Cynanchum bungei Decne. The structures of compounds were elucidated by spectroscopic data and quantum NMR and ECD calculations. Compounds 1 and 2 represented a new family of sulfur containing natural products with a 3-methyl-4H-cyclopenta[b]thiophen-4-one skeleton. Compounds 1-4 showed inhibitory activities against nitric oxide (NO) with IC50 values of 38.0, 19.8, 46.3, and 56.6 µM, respectively.

Atorvastatin Inhibits Inflammatory Response, Attenuates Lipid Deposition, and Improves the Stability of Vulnerable Atherosclerotic Plaques by Modulating Autophagy.

Atherosclerosis is a chronic disease comprising intima malfunction and arterial inflammation. Recent studies have demonstrated that autophagy could inhibit inflammatory response in atherosclerosis and exert subsequent atheroprotective effects. Our previous study also demonstrated the role of autophagy in the inhibition of inflammation by atorvastatin in vitro. Therefore, in the present study, we aimed to determine whether atorvastatin could upregulate autophagy to inhibit inflammatory cytokines secretion, lipid accumulation, and improve vulnerable plaque stability, both in vitro and in vivo. First, we established a vulnerable atherosclerotic plaque mouse model through partial ligation of left common carotid artery and left renal artery to explore the effect of atorvastatin on vulnerable plaques. The results showed that atorvastatin could enhance the stability of vulnerable atherosclerotic plaques and reduce the lesion area in the aorta. Atorvastatin could also inhibit NLRP3 inflammasome activation and inflammatory cytokines, such as IL-1ß, TNF-α, and IL-18 secretion in vivo. Atorvastatin treatment upregulated the expression of autophagy-related protein microtubule-associated protein light chain (LC3B) and downregulated the expression of SQSTM1/p62, which suggested that autophagy was activated in vulnerable plaques. Transmission electron microscopy further demonstrated the atorvastatin-induced increase in autophagy activity in vulnerable atherosclerotic plaques. We employed oxidized low-density lipoprotein (ox-LDL) to stimulate RAW264.7 cells with atorvastatin, which showed that atorvastatin could attenuate lipid deposition, ameliorate inflammation, inhibit NLRP3 inflammasome activation, and enhance autophagy in vitro. All these beneficial effects were abolished by 3-methyladenine treatment, an autophagy inhibitor. Atorvastatin also significantly inhibited the phosphorylation of mTOR, which strongly suggested the involvement of the mTOR pathway. Our study proposed a new role for atorvastatin as an autophagy inducer to exert anti-inflammatory and atheroprotective effects, to stabilize vulnerable atherosclerotic plaques.