The proliferative and migratory abilities of vascular smooth muscle cells (VSMCs) play a crucial role in neointima formation following vascular injury. Skp2 facilitates proliferation and migration in cells through cell cycle regulation, presenting an important therapeutic target for atherosclerosis, pulmonary hypertension, and vascular restenosis. This study aimed to identify a natural product capable of inhibiting neointima formation post vascular injury. Here, we demonstrate that troxerutin, a flavonoid, significantly reduced viability and downregulated Skp2 in VSMCs. Moreover, troxerutin exhibited anti-proliferative effects on VSMCs and mitigated neointima formation. These findings collectively elucidate the intrinsic mechanism of troxerutin in treating atherosclerosis, pulmonary hypertension, and vascular restenosis by targeting the E3-linked enzyme Skp2.

Myocardial ischemia/reperfusion (I/R) injury is a complex pathological process that is still not fully understood. The oxidative stress response has a critical role in the occurrence and progression of myocardial ischemia/reperfusion injury. This study investigated the specific mechanism of ubiquitin-specific protease 7 (USP7) regulation of myocardial ischemia/reperfusion injury from the perspective of proteasome degradation and its relation with the Keap1 pathway, a vital regulator of cytoprotective responses to endogenous and exogenous stress induced by reactive oxygen species (ROS) and electrophiles. Our data indicated that USP7 expression is increased during myocardial ischemia/reperfusion injury in mice, while its inhibiting suppressed the generation of oxygen free radicals and myocardial cell apoptosis, reduced myocardial tissue damage, and improved heart function. Mechanistically, USP7 stabilizes Keap1 by regulating its ubiquitination. Taken together, these findings demonstrate the potential therapeutic effect of USP7 on myocardial ischemia/reperfusion injury.

The underlying mechanism of neointima formation remains unclear. Ubiquitin-specific peptidase 10 (USP10) is a deubiquitinase that plays a major role in cancer development and progression. However, the function of USP10 in arterial restenosis is unknown. Herein, USP10 expression was detected in mouse arteries and increased after carotid ligation. The inhibition of USP10 exhibited thinner neointima in the model of mouse carotid ligation. In vitro data showed that USP10 deficiency reduced proliferation and migration of rat thoracic aorta smooth muscle cells (A7r5) and human aortic smooth muscle cells (HASMCs). Mechanically, USP10 can bind to Skp2 and stabilize its protein level by removing polyubiquitin on Skp2 in the cytoplasm. The overexpression of Skp2 abrogated cell cycle arrest induced by USP10 inhibition. Overall, the current study demonstrated that USP10 is involved in vascular remodeling by directly promoting VSMC proliferation and migration via stabilization of Skp2 protein expression.

Recent studies have highlighted observations regarding re-tested positivity (RP) of SARS-CoV-2 RNA in discharged COVID-19 patients, however, the immune mechanisms underlying SARS-CoV-2 RNA RP in immunocompetent patients remain elusive. Herein, we describe the case of an immunocompetent COVID-19 patient with moderate symptoms who was twice re-tested as positive for SARS-CoV-2 RNA, and the period between first and third viral RNA positivity was 95 days, longer than previously reported (18–25 days). The chest computed tomography findings, plasma anti-SARS-CoV-2 antibody, neutralizing antibodies (NAbs) titer, and whole blood transcriptic characteristics in the viral RNA RP patient and other COVID-19 patients were analyzed. During the SARS-CoV-2 RNA RP period, new lung lesions were observed. The COVID-19 patient with viral RNA RP had delayed seroconversion of anti-spike/receptor-binding domain (RBD) IgA antibody and NAbs and were accompanied with disappearance of the lung lesions. Further experimental data validated that NAbs titer was significantly associated with anti-RBD IgA and IgG, and anti-spike IgG. The RP patient had lower interferon-, T cells- and B cell-related genes expression than non-RP patients with mild-to-moderate symptoms, and displayed lower cytokines and chemokines gene expression than severe patients. Interestingly, the RP patient had low expression of antigen presentation-related genes and low B cell counts which might have contributed to the delayed anti-RBD specific antibody and low CD8+ cell response. Collectively, delayed antigen presentation-related gene expression was found related to delayed adaptive immune response and contributed to the SARS-CoV-2 RNA RP in this described immunocompetent patient.

Atherosclerosis is regarded as a chronic progressive inflammatory disease and is a basic pathophysiological process in coronary artery disease which is life threatening in clinic. The formation of foam cell plays a key role in the pathogenesis of atherosclerosis. OxLDL is a significant factor in progression of coronary artery disease. Our studies have demonstrated that USP14 promotes cancer development and mediates progression of cardiac hypertrophy and LPS-induced inflammation. However, the underlying mechanism of USP14 is unknown. In this study, we found that the inhibition of USP14 significantly suppressed the oxLDL uptake, subsequently decreased the foam cell formation. Surprisingly, USP14 has an effect on the expression of CD36 but not SR-A, ABCA1, Lox-1, ABCG1 and SR-Bl. Furthermore, USP14 stabilizes CD36 protein via cleaving the ubiquitin chain on CD36. Blocking CD36 activation using antibody-dependent blocking assay remarkably attenuated the function of USP14 on the formation of foam cell. In summary, our results suggested that the inhibition of USP14 decreases foam cell formation by down-regulating CD36-mediated lipid uptake and provides a potential therapeutic target for atherosclerosis.

b-AP15 is a deubiquitinase (DUB) inhibitor of 19S proteasomes, which in turn targets ubiquitin C-terminal hydrolase 5 (UCHL5) and ubiquitin-specific peptidase 14 (USP14). Nuclear factor kappa B (NF-κB) is closely linked to cellular response in macrophages when the organism is in the state of microbial infection, and it acts as a vital part in the mechanism of inflammatory reaction. However, the molecular mechanism by which DUB inhibitors, especially b-AP15, regulates inflammation remains poorly understood. This study aimed to investigate the relationship between b-AP15 and inflammation. The results showed that b-AP15 treatment significantly reduced the amounts of inflammatory indicators, such as tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) in lipopolysaccharide (LPS)-stimulated THP-1 and macrophages. Meanwhile, similar results were obtained from in vivo experiments. In addition, b-AP15 also significantly improved the survival rate of sepsis mouse via high-density LPS mediation. Furthermore, b-AP15 also inhibited the ERK1/2 and JNK phosphorylation, increased IκBα levels, and inhibited NF-κB p65 by removing them from the cytoplasm into the nucleus. All these findings suggested that b-AP15 has anti-inflammatory action and acts as a potential neoteric target drug for treating microbial infection.

Exosomes are served as substitutes for stem cell therapy, playing important roles in mediating heart repair during myocardial infarction injury. Evidence have indicated that lipopolysaccharide (LPS) pre‐conditioning bone marrow‐derived mesenchymal stem cells (BMSCs) and their secreted exosomes promote macrophage polarization and tissue repair in several inflammation diseases; however, it has not been fully elucidated in myocardial infarction (MI). This study aimed to investigate whether LPS‐primed BMSC‐derived exosomes could mediate inflammation and myocardial injury via macrophage polarization after MI. Here, we found that exosomes derived from BMSCs, in both Exo and L‐Exo groups, increased M2 macrophage polarization and decreased M1 macrophage polarization under LPS stimulation, which strongly depressed LPS‐dependent NF‐κB signalling pathway and partly activated the AKT1/AKT2 signalling pathway. Compared with Exo, L‐Exo had superior therapeutic effects on polarizing M2 macrophage in vitro and attenuated the post‐infarction inflammation and cardiomyocyte apoptosis by mediating macrophage polarization in mice MI model. Consequently, we have confidence in the perspective that low concentration of LPS pre‐conditioning BMSC‐derived exosomes may develop into a promising cell‐free treatment strategy for clinical treatment of MI.

Background/Aims: Cardiac hypertrophy is a major outcome and compensatory response of the cardiovascular system to hemodynamic and additional stress responses that ultimately lead to heart failure. Auranofin (Aur) has been used for treating rheumatic arthritis for several decades. Aur is a 19S proteasome-associated deubiquitinase inhibitor, and inhibition of the proteasome is speculated to reverse cardiac hypertrophy. However, the role of the deubiquitinases, especially 19S proteasome-associated deubiquitinases, in the regulation of cardiac remodeling remains poorly understood. The present study investigated the role of Aur in cardiac hypertrophy both in vitro and in vivo. Methods: Male Sprague–Dawley rats underwent abdominal aortic constriction to induce left ventricular hypertrophy. The neonatal rat primary myocardial cell hypertrophy model was induced by Ang II. Echocardiography, hematoxylin-eosin staining, Masson’s trichrome staining, immunochemistry, western blot analysis, a cell viability assay, and enzyme-linked immunosorbent assay were performed. Results: Aur significantly reduced the abdominal aortic constriction that led to left ventricular hypertrophy, reduced heart cavity expansion, and functional disorder, and thereby reduced fetal gene expression and attenuated cardiac fibrosis. Furthermore, Aur caused marked accumulation of ubiquitinated proteins and IκBα, as well as inactivation of NF-κB. This phenomenon was confirmed in the neonatal rat primary myocardial cell hypertrophy model. Conclusions: The present study indicated that Aur blocks the development of left ventricular hypertrophy induced by abdominal aortic constriction. This phenomenon might be attributed to inhibition of the 19S proteasome-associated deubiquitinase that can lead to aggregation of IκBα and inactivation of the NF-κB pathway. Thus, Aur could be a potential anti-cardiac hypertrophy agent.

Accumulated evidence indicates that polymorphisms in human leukocyte antigens (HLA) are associated with susceptibility to coronary artery disease (CAD). However, whether HLA-DQB1 alleles are correlated with susceptibility to CAD is unclear. In this study, significantly lower frequencies of the allele groups (DQB1*03:01:01G and DQB1*05:03:01G) and the genotypes (DQB1*03:01:01G/DQB1*03:01:01G and DQB1*03:01:01G/DQB1*05:03:01G) were observed in the CAD group compared with that in the controls. However, notably higher frequencies of DQB1*04:01:01G and genotype DQB1*05:01:01G/DQB1*03:01:01G were observed in the CAD patients than in the controls. Further analysis in subgroups showed that DQB1*03:01:01G was present at a significantly lower frequency in both female and male CAD patients compared with the corresponding controls; however, DQB1*04:01:01G was overtly high only in male CAD patients. CAD patients with diabetes showed a negative association with DQB1*03:01:01G and DQB1*05:03:01G and a positive association with DQB1*04:01:01G, DQB1*03:02:01G and DQB1*03:03:02G. Results of logistic regression analysis indicated that DQB1*03:01:01G and DQB1*05:03:01G were significantly associated with reduced susceptibility to CAD, but DQB1*04:01:01G, DQB1*03:02:01G and DQB1*03:03:02G had no correlation with CAD. Together, these findings indicate that CAD in Southern Han Chinese is negatively associated with HLA-DQB1*03:01:01G and DQB1*05:03:01G, and males with HLA-DQB1*04:01:01G are likely to have high risk for CAD.

Cardiac hypertrophy, a compensatory response to various stimuli in the heart, independently predicts cardiovascular ailments and related deaths. Increasing evidence indicates ubiquitin-proteasome signaling contributes to cardiac hypertrophy regulation. Here, we identified ubiquitin-specific protease 14 (USP14), a 19S proteasome associated deubiquitinase (DUB), as a novel target for cardiac hypertrophy therapy via inhibition of the GSK-3β pathway. Indeed, USP14 expression was increased in an animal model of abdominal aorta constriction. In an angiotensin II (AngII) induced primary neonatal rat cardiomyocyte hypertrophy model, USP14 expression was increased in a time-dependent manner, and reduced USP14 deubiquitinase activity or USP14 knockdown resulted in lower expression levels of the myocardial hypertrophy specific marker β-MHC, and subsequent decreased GSK-3β phosphorylation. In conclusion, USP14 mediates the development of cardiac hypertrophy by promoting GSK-3β phosphorylation, suggesting that USP14 might represent a novel therapeutic target for cardiac hypertrophy treatment.

Objective To investigate the factors related to recurrent coronary events in patients after coronary artery stent implantation. Methods We retrospectively studied the patients performing coronary angiography(CAG) who were admitted to the Department of Cardiology of the Second Affiliated Hospital of Guangzhou Medical University between January 2012 and June 2013. All of the enrolled patients had received CAG in our hospital, with complete coronary angiogram and clinical data. The patients were divided into two groups according to the coronary angiogram and clinical data: coronary event group and non-coronary event group. SPSS 16.0 software was employed for statistical analysis, and multivariate analysis was performed using binary logistic regression model to analyze the risk factors. Results A total of 115 patients were included, of which 50 patients had recurrent coronary events. Both the serum total bilirubin and unconjugated bilirubin in patients with coronary events were significantly lower compared with the patients without coronary events at baseline and at the time of CAG reexamination(P0.05 or P0.01). The serum total bilirubin at baseline and the serum total bilirubin and unconjugated bilirubin at the time of CAG reexamination were significantly lower in patients with revasculization due to the progression of coronary artery lesions compared with the patients without coronary events(P0.05 or P0.01). The serum unconjugated bilirubin in patients with in-stent restenosis were significantly lower compared with the patients without coronary events at baseline and at the time of CAG reexamination(P0.05). The results of logistic regression analysis showed that multi-vessel coronary artery disease(two-vessel coronary artery disease: OR=10.094, 95%CI 2.498 to 40.798, P=0.001; three-vessel coronary artery disease: OR=16.047, 95%CI 4.121 to 62.481, P=0.000) and low serum unconjugated bilirubin(OR=0.873, 95%CI 0.773 to 0.987, P=0.03) were independent risk factors of recurrent coronary events. Conclusion Multi-vessel coronary artery disease and low serum unconjugated bilirubin are independent risk factors of recurrent coronary events in patients after coronary artery stent implantation.