The reactive oxygen species- (ROS-) induced nod-like receptor protein-3 (NLRP3) inflammasome triggers sterile inflammatory responses and pyroptosis, which is a proinflammatory form of programmed cell death initiated by the activation of inflammatory caspases. NLRP3 inflammasome activation plays an important role in myocardial ischemia/reperfusion (MI/R) injury. Our present study investigated whether diabetes aggravated MI/R injury through NLRP3 inflammasome-mediated pyroptosis. Type 1 diabetic rat model was established by intraperitoneal injection of streptozotocin (60 mg/kg). MI/R was induced by ligating the left anterior descending artery (LAD) for 30 minutes followed by 2 h reperfusion. H9C2 cardiomyocytes were exposed to high glucose (HG, 30 mM) conditions and hypoxia/reoxygenation (H/R) stimulation. The myocardial infarct size, CK-MB, and LDH release in the diabetic rats subjected to MI/R were significantly higher than those in the nondiabetic rats, accompanied with increased NLRP3 inflammasome activation and increased pyroptosis. Inhibition of inflammasome activation with BAY11-7082 significantly decreased the MI/R injury. In vitro studies showed similar effects, as BAY11-7082 or the ROS scavenger N-acetylcysteine, attenuated HG and H/R-induced H9C2 cell injury. In conclusion, hyperglycaemia-induced NLRP3 inflammasome activation may be a ROS-dependent process in pyroptotic cell death, and NLRP3 inflammasome-induced pyroptosis aggravates MI/R injury in diabetic rats.

Diabetes aggravates myocardial ischemia-reperfusion (I/R) injury because of the combination effects of changes in glucose and lipid energy metabolism, oxidative stress, and systemic inflammatory response. Studies have indicated that myocardial I/R may coincide and interact with sepsis and inflammation. However, the role of LPS in hypoxia/reoxygenation (H/R) injury in cardiomyocytes under high glucose conditions is still unclear. Our objective was to examine whether lipopolysaccharide (LPS) could aggravate high glucose- (HG-) and hypoxia/reoxygenation- (H/R-) induced injury by upregulating ROS production to activate NLRP3 inflammasome-mediated pyroptosis in H9C2 cardiomyocytes. H9C2 cardiomyocytes were exposed to HG (30 mM) condition with or without LPS, along with caspase-1 inhibitor (Ac-YVAD-CMK), inflammasome inhibitor (BAY11-7082), ROS scavenger N-acetylcysteine (NAC), or not for 24 h, then subjected to 4 h of hypoxia followed by 2 h of reoxygenation (H/R). The cell viability, lactate dehydrogenase (LDH) release, caspase-1 activity, and intracellular ROS production were detected by using assay kits. The incidence of pyroptosis was detected by calcein-AM/propidium iodide (PI) double staining kit. The concentrations of IL-1β and IL-18 in the supernatants were assessed by ELISA. The mRNA levels of NLRP3, ASC, and caspase-1 were detected by qRT-PCR. The protein levels of NF-κB p65, NLRP3, ASC, cleaved caspase-1 (p10), IL-1β, and IL-18 were detected by western blot. The results indicated that pretreatment LPS with 1 μg/ml not 0.1 μg/ml could efficiently aggravate HG and H/R injury by activating NLRP3 inflammasome to mediate pyroptosis in H9C2 cells, as evidenced by increased LDH release and decreased cell viability in the cells, and increased expression of NLRP3, ASC, cleaved caspase-1 (p10), IL-1β, and IL-18. Meanwhile, Ac-YVAD-CMK, BAY11-7082, or NAC attenuated HG- and H/R-induced H9C2 cell injury with LPS stimulated by reversing the activation of NLRP3 inflammasome-mediated pyroptosis. In conclusion, LPS could increase the sensitivity of H9C2 cells to HG and H/R and aggravated HG- and H/R-induced H9C2 cell injury by promoting ROS production to induce NLRP3 inflammasome-mediated pyroptosis.

Patients with diabetes are more vulnerable to myocardial ischemia/reperfusion (MI/R) injury, which is associated with excessive reactive oxygen species (ROS) generation and decreased antioxidant defense. Histone deacetylase 6 (HDAC6), a regulator of the antioxidant protein peroxiredoxin 1 (Prdx1), is associated with several pathological conditions in the cardiovascular system. This study investigated whether tubastatin A (TubA), a highly selective HDAC6 inhibitor, could confer a protective effect by modulating Prdx1 acetylation in a rat model of MI/R and an in vitro model of hypoxia/reoxygenation (H/R). Here, we found that diabetic hearts with excessive HDAC6 activity and decreased acetylated-Prdx1 levels were more vulnerable to MI/R injury. TubA treatment robustly improved cardiac function, reduced cardiac infarction, attenuated ROS generation, and increased acetylated-Prdx1 levels in diabetic MI/R rats. These results were further confirmed by an in vitro study using H9c2 cells. Furthermore, a study using Prdx1 acetyl-silencing mutants (K197R) showed that TubA only slightly attenuated H/R-induced cell death and ROS generation in K197R-transfected H9c2 cells exposed to high glucose (HG), but these differences were not statistically significant. Taken together, these findings suggest that HDAC6 inhibition reduces ROS generation and confers a protective effect against MI/R or H/R injury by modulating Prdx1 acetylation at K197.

Objective Tumour necrosis factor-α-induced protein 8-like 2 (TIPE2) has strong anti-inflammatory properties. However, it is unknown whether increased TIPE2 is protective against lipopolysaccharide (LPS)-induced ALI. In the current study, we aimed to investigate whether increased TIPE2 can exert protective effects in a mouse model of ALI induced by LPS. Methods We administered TIPE2 adeno-associated virus (AAV-TIPE2) intratracheally into the lungs of mice. Three weeks later, ALI was induced by intratracheal injection of LPS into BALB/c mice. Twenty-four hours later, lung bronchoalveolar lavage fluid (BALF) was acquired to analyse cells and protein, arterial blood was collected for arterial blood gas analysis and the determination of pro-inflammatory factor levels, and lung issues were collected for histologic examination, transmission electron microscopy (TEM), TUNEL staining, wet/dry (W/D) weight ratio analysis, myeloperoxidase (MPO) activity analysis and blot analysis of protein expression. Results We found that TIPE2 overexpression markedly mitigated LPS-induced lung injury, which was evaluated by the deterioration of histopathology, histologic scores, the W/D weight ratio, and total protein expression in the BALF. Moreover, TIPE2 overexpression markedly attenuated lung inflammation, as evidenced by the downregulation of polymorphonuclear neutrophils (PMNs) in the BALF, lung MPO activity, and pro-inflammatory cytokine levels in the serum. Moreover, TIPE2 overexpression not only dramatically prevented LPS-induced pulmonary cell apoptosis in mice but also blocked LPS-activated JNK phosphorylation and NF-κB p65 nuclear translocation. Conclusions Our study shows that the increased expression of AAV-mediated TIPE2 in the lungs of mice inhibits acute inflammation and apoptosis and suppresses the activation of NF-κB and JNK in a murine model of ALI. Keywords Acute lung injury • TIPE2 • Apoptosis • Inflammation • Cytokines • NF-κB • JNK Abbreviations ALI Acute lung injury ARDS Acute respiratory distress syndrome BALF Bronchoalveolar lavage fluid ELISA Enzyme-linked immunosorbent assay i.t. Intratracheal LPS Lipopolysaccharide MPO Myeloperoxidase PBS Phosphate-buffered saline PMNs Polymorphonuclear neutrophils TUNEL Deoxynucleotidyl transferase dUTP nick end labeling W/D Wet-to-dry TIPE2 Tumor necrosis factor-α-induced protein 8-like 2

In patients with ischemic heart disease, myocardial ischemia–reperfusion injury (IRI) can aggravate their condition even worse, and diabetes increases their risk of myocardial IRI. Pathological pathways of common diseases and surgical operations like diabetes, obesity, coronary artery angioplasty, and heart transplantation entail disorders of iron metabolism. Ferroportin1 (FPN1) is the only mammalian protein associated with iron release and thus plays a vital role in iron homeostasis, while nuclear factor E2-related factor 2 (NRF2) controls the transcription of FPN1. Since the NRF2/FPN1 pathway may play a favorable role in the therapy of diabetic myocardial IRI, this work investigated the possible mechanism. In this study, we investigated the effects of ferroptosis in STZ-induced diabetic rats following myocardial IRI in vivo, and its alteration in glucose and hypoxia/reoxygenation-induced cardiomyocytes injury in vitro. Rats and H9c2 cardiomyocytes were randomly divided into 6 groups and treated with sulforaphane and erastin besides the establishment of diabetic myocardial IRI and hyperglycemic hypoxia-reoxygenation models. Cardiac functional and structural damage were detected by Evans blue/TTC double staining, echocardiography, HE staining, and serological indices. CCK-8 assay and ROS production were used to measure cardiomyocyte viability and oxidative stress level. Additionally, the changes in cell supernatant levels of Fe2+, SOD, MDA, and mRNA and protein expression of ferroptosis marker proteins confirmed the beneficial effects of the NRF2/FPN1 pathway on diabetic myocardial IRI related to iron metabolism and ferroptosis. Overall, these findings suggest that iron homeostasis-related ferroptosis plays an important role in aggravating myocardial IRI in diabetic rats, and NRF2/FPN1 pathway-mediated iron homeostasis and ferroptosis might be a promising therapeutic target against myocardial IRI in diabetes.

The coronavirus disease 2019 (COVID-19) became a global pandemic. Males, compared to females, seem to be more susceptible to COVID-19, but related evidence is scarce, especially in severe patients. We explored sex differences in clinical characteristics and potential risk factors for mortality in severe COVID-19 patients. In this retrospective cohort study, we included all severe COVID-19 patients admitted to Eastern Renmin Hospital of Wuhan University, Wuhan, China, with a definitive clinical outcome as of Apr 10, 2020. Of the included 651 patients, 332 were male, and 319 were female. Males and females did not differ in age and underlying comorbidities. Males were more likely than females to report fever and develop serious complications, including acute respiratory distress syndrome, secondary infection, acute cardiac injury, coagulopathy, acute kidney injury and arrhythmia. Further, males had much higher mortality relative to females. Multivariable regression showed neutrophilia (odds ratio 6.845, 95% CI 1.227-38.192, p=0.028), thrombocytopenia (19.488, 3.030-25.335, p=0.002), hypersensitive troponin I greater than 0.04 pg/mL (6.058, 1.545-23.755, p=0.010), and procalcitonin greater than 0.1 ng/mL (6.350, 1.396-28.882, p=0.017) on admission were associated with inhospital death. With either of these risk factors, the cumulative survival rate was relatively lower in males than in females. In conclusion, males are more likely than females to develop serious complications and progress to death. The potential risk factors of neutrophilia, thrombocytopenia, hypersensitive troponin I greater than 0.04 pg/mL and procalcitonin more than 0.1 ng/mL may help clinicians to identify patients with poor outcomes at an early stage, especially in males.

We study a practical domain adaptation task, called source-free unsupervised domain adaptation (UDA) problem, in which we cannot access source domain data due to data privacy issues but only a pre-trained source model and unlabeled target data are available. This task, however, is very difficult due to one key challenge: the lack of source data and target domain labels makes model adaptation very challenging. To address this, we propose to mine the hidden knowledge in the source model and exploit it to generate source avatar prototypes (i.e. representative features for each source class) as well as target pseudo labels for domain alignment. To this end, we propose a Contrastive Prototype Generation and Adaptation (CPGA) method. Specifically, CPGA consists of two stages: (1) prototype generation: by exploring the classification boundary information of the source model, we train a prototype generator to generate avatar prototypes via contrastive learning. (2) prototype adaptation: based on the generated source prototypes and target pseudo labels, we develop a new robust contrastive prototype adaptation strategy to align each pseudo-labeled target data to the corresponding source prototypes. Extensive experiments on three UDA benchmark datasets demonstrate the effectiveness and superiority of the proposed method.

The circadian clock is closely related to the development of diabetes mellitus and cardiovascular disease, and disruption of the circadian clock exacerbates myocardial ischaemia/reperfusion injury (MI/RI). HDAC3 is a key component of the circadian negative feedback loop that controls the expression pattern of the circadian nuclear receptor Rev-erbα to maintain the stability of circadian genes such as BMAL1. However, the mechanism by which the HDAC3-orchestrated Rev-erbα/BMAL1 pathway increases MI/RI in diabetes and its relationship with mitophagy have yet to be elucidated. Here, we observed that the clock genes Rev-erbα, BMAL1, and C/EBPβ oscillations were altered in the hearts of rats with streptozotocin (STZ)-induced diabetes, with upregulated HDAC3 expression. Oscillations of Rev-erbα and BMAL1 were rapidly attenuated in diabetic MI/R hearts versus non-diabetic I/RI hearts, in accordance with impaired and rhythm-disordered circadian-dependent mitophagy that increased injury. Genetic knockdown of HDAC3 significantly attenuated diabetic MI/RI by mediating the Rev-erbα/BMAL1 circadian pathway to recover mitophagy. Primary cardiomyocytes with or without HDAC3 siRNA and Rev-erbα siRNA were exposed to hypoxia/reoxygenation (H/R) in vitro. The expression of HDAC3 and Rev-erbα in cardiomyocytes was increased under high-glucose conditions compared with low-glucose conditions, with decreased BMAL1 expression and mitophagy levels. After H/R stimulation, high glucose aggravated H/R injury, with upregulated HDAC3 and Rev-erbα expression and decreased BMAL1 and mitophagy levels. HDAC3 and Rev-erbα siRNA can alleviate high glucose-induced and H/R-induced injury by upregulating BMAL1 to increase mitophagy. Collectively, these findings suggest that disruption of HDAC3-mediated circadian gene expression oscillations induces mitophagy dysfunction, aggravating diabetic MI/RI. Cardiac-specific HDAC3 knockdown could alleviate diabetic MI/RI by regulating the Rev-erbα/BMAL1 pathway to restore the activation of mitophagy.