Uric acid aggravates myocardial ischemia-reperfusion injury via ROS/NLRP3 pyroptosis pathway

Myeloid SHP2 attenuates myocardial ischemia‑reperfusion injury via regulation of BRD4/SYK/STING/NOX4/NLRP3 signaling

The objective of the present study was to investigate the impact of myeloid Src homology region 2‑containing protein tyrosine phosphatase 2 (SHP2) on myocardial ischemia reperfusion (MI/R) injury and the underlying mechanism. Bioinformatics was used to analyze genes specifically associated with MI/R. In addition, myeloid‑specific SHP2 knockout mice and wild‑type mice were subjected to MI/R or sham surgery. Echocardiography and Masson's staining were used to observe the myocardial function and infarct area of the mice. In addition, double immunofluorescence staining was used to detect the relative fluorescence intensity of SHP2 and bromodomain‑containing protein 4 (BRD4) in bone marrow‑derived macrophages (BMMs) from the mice. Western blot analysis was conducted to determine the expression levels of SHP2, BRD4, spleen tyrosine kinase (SYK), stimulator of interferon genes (STING), NADPH oxidase 4 (NOX4), NLR family pyrin domain containing 3 (NLRP3), IL‑1β and gasdermin D (GSDMD) in BMMs and mouse myocardial cells co‑cultured with the BMMs. In addition, flow cytometry was employed to assess myocardial cell apoptosis. Bioinformatics analysis revealed the downregulated expression of SHP2 and upregulated expression of BRD4 and SYK in mice with MI/R. The deletion of myeloid SHP2 aggravated MI/R injury, impaired cardiac function and increased the infarct area in mice. In addition, myeloid SHP2 deletion in BMMs promoted the expression of BRD4, SYK, STING, NOX4 and NLRP3 in BMMs, and the expression of IL‑1β and GSDMD in mouse myocardial cells co‑cultured with the BMMs. In addition, the deletion of myeloid SHP2 promoted cardiomyocyte apoptosis. These results indicate that myeloid SHP2 inhibits MI/R injury by regulating BRD4/SYK/STING/NOX4/NLRP3 signaling in BMMs.

Hyperuricemia Exacerbates Experimental Periodontitis via Uric Acid-Induced Periodontal Inflammation and Oxidative Stress

AIM

To investigate the effects of hyperuricemia on periodontitis and the underlying mechanisms by establishing combined animal and cell models.

METHODS

A hyperuricemia mouse model was established by potassium oxonate injection, with sodium carboxymethylcellulose treatment serving as controls. Both models were treated with or without periodontitis induction (n = 10/group). RAW264.7 macrophages and THP-1-derived macrophages were stimulated with Porphyromonas gingivalis -lipopolysaccharide in the presence of normal or excessive concentrations of uric acid. Allopurinol intervention was applied to both animal and cell models. Periodontal destruction was measured by micro-computed tomography and histology. The immune response and oxidative stress in the periodontium and macrophages were assessed using various methods including immunohistochemistry, quantitative PCR, western blotting, flow cytometry and multiplex cytokine assays.

RESULTS

Potassium oxonate successfully induced hyperuricemia without affecting serum glucose/lipid levels or xanthine oxidoreductase activity. In mice with periodontitis, hyperuricemia exacerbated alveolar bone loss and the presence of osteoclasts and M1 macrophages. Mechanistically, hyperuricemia promoted NLRP3 inflammasome activation, disrupted the inflammatory cytokine response and exacerbated oxidative stress both in the periodontium and in vitro. Allopurinol treatment reversed all relevant changes in both mice and macrophages.

CONCLUSION

Hyperuricemia exacerbates periodontitis possibly via uric acid-induced periodontal inflammation and oxidative stress.

The Regulatory Role of NcRNAs in Pyroptosis and Disease Pathogenesis

Non-coding RNAs (ncRNAs), as critical regulators of gene expression, play a pivotal role in the modulation of pyroptosis and exhibit a close association with a wide range of diseases. Pyroptosis is a form of programmed cell death mediated by inflammasomes, characterized by cell membrane perforation, release of inflammatory cytokines, and a robust immune response. Recent studies have revealed that ncRNAs influence the initiation and execution of pyroptosis by regulating the expression of pyroptosis-related genes or modulating associated signaling pathways. This review systematically summarizes the molecular mechanisms and applications of ncRNAs in diseases such as cancer, infectious diseases, neurological disorders, cardiovascular diseases, and metabolic disorders. It further explores the potential of ncRNAs as diagnostic biomarkers and therapeutic targets, elucidates the intricate interactions among ncRNAs, pyroptosis, and diseases, and provides novel strategies and directions for the precision treatment of related diseases.

Shen-fu Injection Modulates HIF- 1α/BNIP3-Mediated Mitophagy to Alleviate Myocardial Ischemia-Reperfusion Injury

Coronary reperfusion therapy is the most common surgical treatment for myocardial infarction, but it can further induce myocardial ischemia-reperfusion injury (MIRI). Therefore, MIRI following coronary intervention is a challenging clinical issue. This study aims to investigate the involvement of HIF- 1α/BNIP3-mediated mitophagy in the protective effects of Shen-fu Injection (SFI) on MIRI in rats. Key targets and signaling pathways of myocardial MIRI were analyzed using high-throughput transcriptome data from the GSE240842 dataset in the GEO database.To establish the MIRI rat model, the left anterior descending coronary artery was ligated for 30 min, followed by reperfusion for 120 min. Hypoxia/reoxygenation (H/R) in neonatal rat primary cardiomyocytes was induced by oxygen-glucose deprivation for 4 h, followed by reoxygenation for 2 h. Two hours after reperfusion, assessments included myocardial infarction area, CK-MB, CTnI, HE staining, TUNEL, mitochondrial ultrastructure and autophagosomes, HIF- 1α, BNIP3, LC3B-II, LC3B-I protein expression, immunofluorescence, and qRT-PCR. Cardiac function was also evaluated using M-mode ultrasound 2 h after reperfusion. In cardiomyocytes, CCK- 8, EdU cell proliferation levels, scratch assay, mitochondrial membrane potential, ROS levels, cardiomyocyte apoptosis, protein expression levels, and immunofluorescence were assessed 2 h after reoxygenation. Our results indicate that HIF- 1α and BNIP3 are key targets in MIRI. SFI upregulates HIF- 1α expression, promoting moderate mitophagy. This process clears excessively damaged mitochondria, reduces cardiomyocyte apoptosis, and decreases myocardial injury. Additionally, SFI reduces autophagosome accumulation, lowers ROS production, and stabilizes membrane potential. Consequently, the area of myocardial infarction is reduced, and cardiac function is improved. SFI activates the HIF- 1α/BNIP3 pathway to mediate moderate mitophagy, effectively reducing cardiomyocyte apoptosis and alleviating myocardial ischemia-reperfusion injury, thereby protecting cardiomyocytes.

Dynamic and Static Effects of the Systemic Inflammatory Response Index on All-Cause Mortality in Individuals With Atherosclerotic Cardiovascular Disease: Evidence From National Health and Nutrition Examination Survey

Objective: This research focuses on analyzing the link between the systemic inflammatory response index (SIRI) and all-cause mortality in individuals with atherosclerotic cardiovascular disease (ASCVD) . Methods: This research analyzed data from 4693 patients using nine cycles of the National Health and Nutrition Examination Survey (NHANES). The connection between SIRI and mortality was determined by employing survey-weighted Cox models, with hazard ratios (HRs) and 95% confidence intervals (CIs) being computed. Kaplan-Meier method illustrated survival differences across SIRI levels. Sensitivity analyses involved restricted cubic splines (RCS), stratified analysis, and E-value calculations. Landmark analysis assessed survival differences at multiple follow-up intervals, while time-dependent receiver operating characteristic curves evaluated SIRI's prognostic value. Mediation analysis identified potential intermediaries impacting the SIRI-mortality relationship. Results: Over 406,564 person-months, 1933 deaths occurred. Adjusted Cox models discovered that higher SIRI was connected with elevated overall mortality [HR 1.192, (95% CI 1.131-1.256), p < 0.001]. Higher SIRI consistently showed lower survival probabilities. RCS and stratified analysis confirmed the robustness of these findings. Survival probability at different follow-up periods was considerably lower in those with higher SIRI. Additionally, SIRI demonstrated a prognostic value of 0.66 for all-cause mortality at 1 year and 3 years, and 0.65 at 5 years. Notably, serum uric acid (6.2%) partially mediated the connection between SIRI and mortality from all causes. Conclusion: In ASCVD patients, SIRI was robustly correlated with all-cause mortality, partially mediated by serum uric acid.

Hydrolysate of goat milk casein supplementation alleviates hyperuricemia and modulates gut microbiota in C57BL6/J mice

Over the past two decades, the occurrence of hyperuricemia and its influence on health have drawn lots of concern all over the world. Despite significant advances in understanding the pathogenesis of hyperuricemia in various studies, effective medications without side effects are not available. Nutraceutical supplements have attracted much attention due to their beneficial and non-toxic side effects compared to chemical compounds. In the present study, mice with hyperuricemia induced by potassium oxalate and hypoxanthine were given hydrolysate of goat milk casein (HGMC) to investigate its beneficial effects on hyperuricemia. HGMC significantly alleviated body weight loss and abnormal water consumption in hyperuricemic mice. Further study showed that HGMC effectively eliminated renal histological damage in mice with hyperuricemia. Real-time PCR and western blot results revealed that HGMC alleviated protein levels of inflammation-associated proteins and cellular pyroptosis-associated proteins, including NLRP3, TNF-α, Caspase1 and TGF-β. Intestinal microbial sequencing showed that supplementation of HGMC increased the abundance of beneficial bacteria and decreased pathogenic flora. In conclusion, our results suggest that the beneficial effects of HGMC on hyperuricemia are associated with regulating inflammation and modulating intestinal bacteria in mice.

Targeting the NLRP3 inflammasome in Parkinson's disease: From molecular mechanism to therapeutic strategy

Parkinson's disease is the second most common neurodegenerative disease, characterized by substantial loss of dopaminergic (DA) neurons, the formation of Lewy bodies (LBs) in the substantia nigra, and pronounced neuroinflammation. The nucleotide-binding domain like leucine-rich repeat- and pyrin domain-containing protein 3 (NLRP3) inflammasome is one of the pattern recognition receptors (PRRs) that function as intracellular sensors in response to both pathogenic microbes and sterile triggers associated with Parkinson's disease. These triggers include reactive oxygen species (ROS), misfolding protein aggregation, and potassium ion (K+) efflux. Upon activation, it recruits and activates caspase-1, then processes the pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18, which mediate neuroinflammation in Parkinson's disease. In this review, we provide a comprehensive overview of NLRP3 inflammasome, detailing its structure, activation pathways, and the factors that trigger its activation. We also explore the pathological mechanisms by which NLRP3 contributes to Parkinson's disease and discuss potential strategies for targeting NLRP3 as a therapeutic approach.

Programmed cardiomyocyte death in myocardial infarction

Cardiovascular disease (CVD) is a leading cause of human mortality worldwide, with patients often at high risk of heart failure (HF) in myocardial infarction (MI), a common form of CVD that results in cardiomyocyte death and myocardial necrosis due to inadequate myocardial perfusion. As terminally differentiated cells, cardiomyocytes possess a severely limited capacity for regeneration, and an excess of dead cardiomyocytes will further stress surviving cells, potentially exacerbating to more extensive heart disease. The article focuses on the relationship between programmed cell death (PCD) of cardiomyocytes, including different forms of apoptosis, necrosis, and autophagy, and MI, as well as the potential application of these mechanisms in the treatment of MI. By gaining a deeper understanding of the mechanisms of cardiomyocyte death, it aims to provide new insights into the prevention and treatment of MI.

Different types of cell death and their interactions in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R) injury is a multifaceted process observed in patients with coronary artery disease when blood flow is restored to the heart tissue following ischemia-induced damage. Cardiomyocyte cell death, particularly through apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, is pivotal in myocardial I/R injury. Preventing cell death during the process of I/R is vital for improving ischemic cardiomyopathy. These multiple forms of cell death can occur simultaneously, interact with each other, and contribute to the complexity of myocardial I/R injury. In this review, we aim to provide a comprehensive summary of the key molecular mechanisms and regulatory patterns involved in these five types of cell death in myocardial I/R injury. We will also discuss the crosstalk and intricate interactions among these mechanisms, highlighting the interplay between different types of cell death. Furthermore, we will explore specific molecules or targets that participate in different cell death pathways and elucidate their mechanisms of action. It is important to note that manipulating the molecules or targets involved in distinct cell death processes may have a significant impact on reducing myocardial I/R injury. By enhancing researchers' understanding of the mechanisms and interactions among different types of cell death in myocardial I/R injury, this review aims to pave the way for the development of novel interventions for cardio-protection in patients affected by myocardial I/R injury.

Injured Myocardium-Targeted Theranostic Nanoplatform for Multi-Dimensional Immune-Inflammation Regulation in Acute Myocardial Infarction

Pyroptosis is a key mode of programmed cell death during the early stages following acute myocardial infarction (AMI), driving immune-inflammatory responses. Cardiac resident macrophages (CRMs) are the primary mediators of cardiac immunity, and they serve a dual role through their shaping of both myocardial injury and post-AMI myocardial repair. To appropriately regulate AMI-associated inflammation, HM4oRL is herein designed, an innovative bifunctional therapeutic nanoplatform capable of inhibiting cardiomyocyte pyroptosis while reprogramming inflammatory signaling. This HM4oRL platform is composed of a core of 4-Octyl itaconate (4-OI)-loaded liposomes, a middle layer consisting of a metal-polyphenol network (MPN) film, and an optimized outer hybrid immune-cell membrane layer. The unique properties of this hybrid membrane layer facilitated HM4oRL targeting to the injured myocardium during early-stage AMI in mice, whereupon the release of 4-Ol and modified MPN synergistically inhibited cardiomyocyte pyroptosis while suppressing inflammatory monocytes/macrophage responses at the infarcted site. Mechanistically, HM4oRL preserved cardiac metabolic homeostasis through AMPK signaling activation, establishing favorable microenvironmental conditions for the reprogramming of CRM-mediated inflammation. Ultimately, HM4oRL treatment is able to resolve inflammation, enhance neovascularization, and suppress myocardial fibrosis, reducing the infarct size and enhancing post-AMI cardiac repair such that it is an innovative approach to the targeted treatment of AMI.

A New Perspective on the Prediction and Treatment of Stroke: The Role of Uric Acid

Stroke, a major cerebrovascular disease, has high morbidity and mortality. Effective methods to reduce the risk and improve the prognosis are lacking. Currently, uric acid (UA) is associated with the pathological mechanism, prognosis, and therapy of stroke. UA plays pro/anti-oxidative and pro-inflammatory roles in vivo. The specific role of UA in stroke, which may have both neuroprotective and damaging effects, remains unclear. There is a U-shaped association between serum uric acid (SUA) levels and ischemic stroke (IS). UA therapy provides neuroprotection during reperfusion therapy for acute ischemic stroke (AIS). Urate-lowering therapy (ULT) plays a protective role in IS with hyperuricemia or gout. SUA levels are associated with the cerebrovascular injury mechanism, risk, and outcomes of hemorrhagic stroke. In this review, we summarize the current research on the role of UA in stroke, providing potential targets for its prediction and treatment.

N-benzyl-N-methyldecane-1-amine derived from garlic ameliorates UVB-induced photoaging in HaCaT cells and SKH-1 hairless mice

Skin tissue is susceptible to oxidative stress-induced senescence provoked by ultraviolet (UV) exposure in our daily lives, resulting in photoaging. Herein, we explore whether N-benzyl-N-methyldecan-1-amine (BMDA) derived from garlic ameliorates UVB-induced photoaging. To address this issue, HaCaT keratinocytes were exposed to UVB irradiation under BMDA treatment. The presence of BMDA substantially reduced UVB-induced ROS levels in a dose-dependent manner. BMDA administration counteracted UVB-induced senescence in the β-galactosidase assay. Treatment with BMDA also rescued UVB-exposed cells (S phase; from 18.3 to 25.8%) from cell cycle arrest, similar to the level observed in untreated normal cells. These findings might support our observation that elevated levels of γ-H2AX, a DNA damage marker, under UVB exposure were reduced following BMDA administration. Additionally, BMDA treatment indirectly reduced UVB-induced melanin synthesis in melanocytes since BMDA failed to inhibit tyrosinase activity, a crucial enzyme in melanin synthesis. The topical application of BMDA on the skin of SKH-1 hairless mice also diminished wrinkle formation, supported by recovered collagen levels and the thickness of the epidermis and dermis, compared to those of UVB-control mice. Finally, the BMDA treatment diminished the expression of inflammatory cytokine transcripts such as TNF-α, IL-1β, IL-4, and IL-6 in the UVB-exposed skin tissues. This finding is further supported by Immunofluorescence microscopy, which showed a decrease in the expression of TNF-α, and IL-1β during BMDA treatment. Altogether, as BMDA mitigates UVB-induced photoaging by reducing ROS production, protecting against DNA damage, and suppressing inflammatory cytokine production, it has been proposed as an effective anti-photoaging molecule.

Artemisinin antagonizes cognitive disorder in hyperuricemia through glutamate receptor-interacting protein 1-suppressed pyroptosis

The prevalence of hyperuricemia (HUA) is climbing worldwide and persistent elevation of serum uric acid impairs cognitive function. This study aimed to explore the mechanisms of Artemisinin (Art) antagonizing cognitive disorder in HUA by suppressing pyroptosis. A mouse model of HUA was established by intraperitoneal injection of 300 mg/kg potassium oxonate (PO) in C57BL/6 mice for 14 days. The mice were simultaneously treated with Art, an agonist of pyroptosis Polyphyllin VI (PPVI), or glutamate receptor-interacting protein 1 (GRIP1) knockdown lentiviral plasmid. After treatment, serum uric acid, IL-6, and TNF-ɑ levels were examined, as well as hippocampal IL-1β and IL-18 levels, and the cognitive function of mice was assessed by the Morris water maze test. Pathological changes in the CA1 of the hippocampus were observed. Cleave-caspase-1, GSDMD-N, and GRIP1 protein level in the hippocampus was quantified by western blot. After PO induction, the escape latency and the time spent in the target quadrant increased in mice, cell arrangement in CA1 hippocampus was loose and disorganized, with obvious inflammatory infiltration and serious damage being observed, and the mouse hippocampus had elevated cleaved-caspase-1, GSDMD-N, IL-1β, and IL-18. Art treatment reduced pyroptosis in the hippocampus and improved cognitive disorder in HUA mice. Administration of PPVI aggravated cognitive disorder in Art-treated HUA mice, and Art improved cognitive dysfunction in HUA mice by inhibiting pyroptosis through upregulation of GRIP1. Art blunts pyroptosis in the hippocampus of HUA mice suffering from cognitive disorder by upregulating GRIP1.

The cascade of cadmium toxicity: from cellular damage to pyroptotic responses in fish Channa punctatus

Cadmium pollution is a major environmental issue threatening aquatic ecosystems and the health of aquatic organisms. Our study examines cadmium toxicity at different levels, highlighting pyroptotic cell death in the freshwater fish Channa punctatus (spotted snakehead). For this purpose, 90 well-acclimatized fish were categorized into three groups: one control and two treatment groups, i.e., T1 and T2, which were exposed to two sub-lethal concentrations of cadmium chloride (Cdcl2), i.e., 1.18 mg/L (one-tenth of 96-h lethal concentration [LC50]) and 2.36 mg/L (one-fifth of 96-h LC50), respectively, for a duration of 7, 14, and 21 days. Post-completion of experimental periods, various assessments were carried out. Reactive oxygen species levels significantly increased, indicating enhanced oxidative stress, along with elevated activities of superoxide dismutase and catalase (P < 0.05). In contrast, reduced glutathione levels decreased in a dose- and duration-dependent manner (P < 0.05). Additionally, lipid peroxidation increased markedly, and liver biomarkers, including serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, alkaline phosphatase, and lactate dehydrogenase, were significantly elevated (P < 0.05) in a time- and concentration-dependent pattern. Histopathological investigations of liver revealed pronounced deformities that were dose-dependent, with higher concentrations of cadmium causing more severe damage. Subsequently, prolonged cadmium exposure led to pyroptosis in the hepatocytes, characterized by the elevated expression of nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3; caspase-1, interleukin-1β, interleukin-18; apoptosis-associated speck-like protein containing a CARD; and Gasdermin E. These results highlighted the significant impact of cadmium on C. punctatus, underscoring its importance as a key bio-indicator for aquatic pollution. The study emphasizes the urgent need to monitor and regulate cadmium levels to protect aquatic life and maintain ecological balance.

TRIM44 alleviates renal ischemia-reperfusion injury by inhibiting pyroptosis through the NLRP3 pathway

BACKGROUND

Renal ischemia-reperfusion injury (IRI) is a prevailing manifestation of acute kidney injury (AKI) with limited treatment options. TRIM44 has emerged as a possible target for treatment due to its regulatory function in inflammatory pathways.

METHODS

In vivo and in vitro models were employed to ascertain the TRIM44 impact on renal IRI. In vivo, we induced IRI in mice and assessed histological changes, oxidative stress markers, and pyroptosis-related proteins. In vitro, we subjected renal cells to hypoxia/reoxygenation (H/R) and manipulated TRIM44 expression to evaluate its effects on cell viability and pyroptosis.

RESULTS

IRI significantly increased inflammation, oxidative stress, and pyroptosis in both animal and cell models, evidenced by elevated cleaved caspase-1, GSDMD-N, and IL-1β/-18 levels. IRI conditions experienced a mitigated TRIM44 expression. Overexpression of TRIM44 in renal cells reduced pyroptosis, as shown by decreased levels of pyroptosis-related proteins and inflammatory cytokines and improved cell viability. Mechanistically, TRIM44 inhibited the NLRP3 inflammasome, as evidenced with reduced NLRP3 and cleaved caspase-1 levels upon TRIM44 overexpression and NLRP3 inhibition. In vivo, intravenous administration of TRIM44-expressing adenovirus post-IRI ameliorated renal damage, as reported with mitigated serum creatinine and blood urea nitrogen levels.

CONCLUSION

TRIM44 protects against renal IRI by inhibiting pyroptosis via the NLRP3 pathway, suggesting its potential to be targeted therapeutically for treating AKI.

Ubiquitin-specific protease 25 improves myocardial ischemia-reperfusion injury by deubiquitinating NLRP3 and negatively regulating NLRP3 inflammasome activity in cardiomyocytes

BACKGROUND

Myocardial ischemia/reperfusion injury (MI/RI) restricts the effect of myocardial reperfusion therapy and lacks effective prevention and treatment methods. Deubiquitinating enzymes (DUBs), especially members of the ubiquitin-specific protease (USP) family of DUBs, are key proteins in the ubiquitination modification process and play a vital role in MI/RI. Therefore, we aimed to investigate the role of USP25, as a member of the USP family, in MI/RI and its molecular mechanism.

METHODS

Transcriptome sequencing was applied to evaluate the differential expression of USP families during hypoxia/reoxygenation (H/R) and validated in human and mouse heart samples and cardiomyocytes by performing quantitative polymerase chain reaction. Wild-type or USP25-/- mice were used to develop the MI/RI model. Co-immunoprecipitation (Co-IP) combined with liquid chromatography-tandem mass spectrometry analysis was used to screen the potential substrate protein of USP25 in H/R-induced cardiomyocyte injury. TUNEL and Hoechst/propidium iodide staining and western blot were used to detect the level of pyroptosis. In addition, cardiomyocyte-specific USP25 overexpression in NLRP3-/- mice with AAV9 vectors was used to validate the biological function of USP25 and NLRP3 interaction.

RESULTS

We found that the expression level of USP25 was significantly decreased in I/R-induced mouse heart tissues and primary cardiomyocytes in a time-dependent manner. USP25 deficiency exacerbated MI/RI and aggravated I/R-induced cardiac remodelling in mice. Mechanistically, USP25 directly binds to NLRP3 protein and K63-linkedly deubiquitinates NLRP3 at residue K243 via its active site C178, thus hindering NLRP3-ASC interaction and ASC oligomerization to inhibit NLRP3 activation and pyroptosis in cardiomyocytes. We further showed that the overexpression of USP25 in cardiomyocytes ameliorated MI/RI in mice, whereas this protective effect disappeared when NLRP3 is knocked out.

CONCLUSIONS

Our study demonstrated that USP25 ameliorates MI/RI by regulating NLRP3 activation and its mediated pyroptosis. This finding extends the protective role of USP25 in cardiovascular disease and provides an experimental basis for future USP25-based drug development for the treatment of MI/RI.

KEY POINTS

The deubiquitinating enzyme USP25 was down-regulated both in myocardial ischemia/reperfusion injury (MI/RI) myocardium tissues. The deficiency of USP25 worsened exacerbated MI/RI in mice, whereas the overexpression of USP25 in cardiomyocytes mitigated this pathological phenotype. USP25 directly interacts with the NLRP3 protein and deubiquitinates it via K63 linkage at residue K243 through its active site C178, thus affecting NLRP3-ASC interaction and ASC oligomerization to inhibit NLRP3 activation and pyroptosis in cardiomyocytes.

Therapeutic Potential of Gasdermin D-Mediated Myocardial Pyroptosis in Ischaemic Heart Disease: Expanding the Paradigm From Bench to Clinical Insights

Ischaemic heart disease (IHD) remains a leading cause of global morbidity and mortality. One significant contributor to the pathology of IHD is the excessive release of inflammatory mediators during the disease progression. Pyroptosis is a form of programmed cell death (PCD) triggered by the activation of inflammasomes and caspase 1. The activation of inflammatory caspase 1 proteolytically cleaves gasdermin D (GSDMD) to the activated form amino acid terminus (GSDMD-NT), leading to disruption of the plasma membrane. This cascade of events is considered the canonical pathway of pyroptosis. IHD also caused oxidative stress, thereby triggering noncanonical pyroptosis via the activation of caspases 4/5/11. Previous studies have provided compelling evidence of the close relationship between pyroptosis and the aetiology of IHD (e.g., acute myocardial infarction, myocardial ischaemia and reperfusion injury and chronic myocardial infarction), as well as the association of pyroptosis with unfavourable clinical outcomes. Several interventions aimed at targeting pyroptosis have demonstrated promising therapeutic benefits against IHD-related pathologies. This review provides mechanistic insights into the roles of pyroptosis in IHD from in vitro, in vivo and clinical perspectives. In-depth understanding into this area could also pave the way for the future development of novel therapeutic strategies targeting pyroptosis in IHD.

Proteomic Screening of Early Reperfusion in Acute Ischemic Heart and Insights into Mitochondrial-Associated Cell Damage: Role of RIP3

BACKGROUND

Regulated forms of necrosis-like cell death (e.g., necroptosis) have been shown to contribute to cardiac ischemia/reperfusion (I/R) injury. However, pro-inflammatory necroptosis is unlikely to be involved during early reperfusion and little is known about the associated molecular changes. Thus, this study aimed to provide an in-depth protein screening with a particular focus on pro-pyroptotic and mitochondrial damage-related pathways.

METHODS

Langendorff-perfused rat hearts were subjected to 30-minute global ischemia followed by 10-minute reperfusion. Liquid chromatography coupled with mass spectrometry (LC-MS/MS) and immunoblotting techniques were used to study the complex cardiac proteome. In addition, calcium-induced mitochondrial swelling and lactate dehydrogenase (LDH) release were examined to assess mitochondrial stress and necrosis phenotype, respectively.

RESULTS

Approximately 160 proteins linked to cell death signaling, cellular metabolism, and post-translational modifications were significantly differentially expressed in I/R hearts compared to controls. Conventional proteins of pyroptosis, either of canonical or non-canonical signaling, were not affected during the short reperfusion. Notably, this type of I/R was associated with increased expression of p25 cleaved form of poly [ADP-ribose] polymerase 1 (PARP1 p25) and mature apoptosis-inducing factor (AIF), alongside nitrosative stress and mitochondrial swelling. Conversely, a receptor-interacting protein kinase 3 (RIP3) inhibitor (GSK'872, 250 nM) reversed mitochondrial swelling and plasma membrane rupture and mitigated the increase in the expression of PARP1 p25 and AIF.

CONCLUSIONS

This study shows for the first time that necrosis-like injury during early I/R of the isolated heart is associated with mitochondrial events, rather than pro-inflammatory pyroptotic cell death. Furthermore, the inhibition of RIP3 mitigates this injury independent of targeting pro-inflammatory signaling.

A Cell Autonomous Free fatty acid receptor 4 - ChemR23 Signaling Cascade Protects Cardiac Myocytes from Ischemic Injury

Acute myocardial infarction (AMI) causes ischemic damage and cardiac remodeling that ultimately progresses into ischemic cardiomyopathy (ICM). Coronary revascularization reduces morbidity and mortality from an MI, however, reperfusion also induces oxidative stress that drives cardiac myocyte (CM) dysfunction and ICM. Oxidative stress in CMs leads to reactive oxygen species (ROS) production and mitochondrial damage. Free fatty acid receptor 4 (Ffar4) is a GPCR for long chain fatty acids (FA) that is expressed in multiple cell types including CMs. We have recently shown that CM-specific overexpression of Ffar4 protects the heart from systolic dysfunction in the context of ischemic injury. Mechanistically, in CMs, Ffar4 increases the levels of 18-hydroxyeicosapentaenoic acid (18-HEPE), an eicosapentaenoic acid (EPA)-derived, cardioprotective oxylipin (oxidatively modified FA). 18-HEPE is the precursor for resolvin E1 (RvE1), a cardioprotective, specialized pro-resolving mediator (SPM) that activates the GPCR ChemR23. We hypothesize Ffar4 in CMs protects the heart from oxidative stress and ischemic injury through activation of a CM-autonomous, Ffar4-ChemR23 cardioprotective signaling pathway. Here, we developed an in vitro hypoxia reoxygenation (H/R) model (3 hours of hypoxia, 17 hours of reoxygenation) in adult CMs as a model for ischemic injury. In adult CMs subjected to H/R, TUG-891, an Ffar4 agonist, attenuated ROS generation and TUG-891, 18-HEPE, and RvE1 protected CMs from H/R-induced cell death. More importantly, we found that the ChemR23 antagonist α-NETA prevented TUG-891 cytoprotection in adult CMs subjected to H/R, demonstrating that ChemR23 is required for Ffar4 cardioprotection. In summary, our data demonstrate co-expression of Ffar4 and ChemR23 in the same CM, that Ffar4, 18-HEPE, and RvE1 attenuate H/R-induced CM death, and that ChemR23 is required for Ffar4 cardioprotection in H/R support a CM-autonomous Ffar4-ChemR23 cardioprotective signaling pathway.

Uric acid mediates kidney tubular inflammation through the LDHA/ROS/NLRP3 pathway

PURPOSE

Hyperuricemia (HUA) is an important factor leading to chronic kidney disease (CKD). The kidney tubular inflammatory response is activated in HUA. This study aimed to investigate whether lactate dehydrogenase A (LDHA) is involved in mediating uric acid-induced kidney tubular inflammatory response.

METHODS

In vivo, an HUA mouse model was established by continuous intraperitoneal injection of potassium oxonate (PO) for one week. A total of 18 C57BL/6J male adult mice were divided into three groups: control group, HUA group, and HUA+oxamate group, with six mice in each group. Oxamate was intraperitoneally injected into the mice one hour after PO injection. In vitro, an HUA model was simulated by stimulating HK-2 cells with uric acid. Oxamate and tempol inhibited LDHA and reactive oxygen species (ROS) in HK-2 cells.

RESULTS

In HUA mice, blood uric acid levels were significantly elevated. LDHA in kidney tubular cells was significantly increased in both in vivo and in vitro HUA models, accompanied by an increase in kidney tubular inflammation and ROS. Mechanistically, LDHA mediates uric acid-induced inflammation to kidney tubular cells through the ROS/NLRP3 pathway. Pharmacologic inhibition of LDHA or ROS in kidney tubular cells can significantly ameliorate inflammation response caused by uric acid.

CONCLUSIONS

LDHA in kidney tubular cells significantly was increased in HUA models. LDHA mediates kidney inflammation response induced by uric acid through the ROS/NLRP3 pathway. This study may provide a new intervention target for preventing kidney tubular inflammation caused by uric acid.

Analysis of uric acid and high-density lipoprotein levels in refractory posner-schlossman syndrome patients: a matched case-control study by the propensity score

BACKGROUND

Recent studies have indicated that oxidative stress is a crucial pathophysiological process in glaucoma. We hypothesized that Posner-Schlossman syndrome (PSS) is a vascular inflammation in the ciliary body due to oxidative stress and endothelial dysfunction. Thus, we investigated serum uric acid (UA) and lipid levels in patients with refractory PSS with the aim of providing basic evidence for the mechanism of PSS.

METHODS

This is a retrospective, case-control study. A total of 81 refractory PSS and 409 control participants were included in this study. Clinical and laboratory characteristics were reviewed using an electronic medical system. Propensity score-matched (PSM) analysis was performed to reduce demographic differences. The t-test, Mann-Whitney U test, and χ2 test were used to assess the differences between the PSS and control groups. Logistic regression analysis was used to identify the predictors of PSS.

RESULTS

The higher serum UA (364.14 ± 98.72µmol/L vs. 322.38 ± 72.09µmol/L), higher low-density lipoprotein (LDL) / High-density lipoprotein (HDL) ratio (2.50 ± 0.97 vs. 1.95 ± 0.72) and lower HDL (1.29 ± 0.32 mmol/L vs. 1.59 ± 0.38 mmol/L) can be noticed in refractory PSS than control group. Logistics regression identified UA > 420 µmol/L (OR = 4.461) and the HDL < 1.03 mmol/L (OR = 3.896) were the independent risk factors for refractory PSS.

CONCLUSIONS

Increasing serum UA and decreasing HDL levels were positively correlated with the incidence risk of refractory PSS. Further prospective longitudinal studies and animal models are needed.

METTL3, m6A modification, and EGR1: interplay affecting myocardial I/R injury outcomes

The occurrence of severe myocardial ischemia/reperfusion (I/R) injury is associated with the clinical application of reestablishment technique for heart disease, and understanding its underlying mechanisms is currently an urgent issue. Prior investigations have demonstrated the potential enhancement of MIRI through EGR1 suppression, although the precise underlying regulatory pathways require further elucidation. The core focus of this investigation is to examine the molecular pathways through EGR1 regulates mitophagy-mediated myocardial cell pyroptosis and its impact on MIRI. Cardiomyocyte hypoxia/reoxygenation (H/R) injury models and mouse models of myocardial I/R injury were used to investigate the involvement of EGR1 in regulating mitophagy-mediated myocardial cell pyroptosis in myocardial I/R injury. The research outcomes demonstrated that under H/R conditions, EGR1 expression was upregulated and inhibited the JAK2/STAT3 pathway, leading to enhanced mitophagy and disrupted mitochondrial fusion/fission dynamics, ultimately resulting in myocardial cell pyroptosis. Further research revealed that the upregulation of EGR1 expression was mediated by methyltransferase like 3 (METTL3)-mediated m6A modification of EGR1 mRNA and depended on the binding of insulin like growth factor 2 mrna binding protein 2 (IGF2BP2) to the N6-methyladenosine (m6A) modification site to enhance mRNA stability. In vivo animal experiments confirmed that METTL3 upregulated EGR1 expression through IGF2BP2 and suppressed activation of the janus kinase 2 (JAK2) /signal transducer and activator of transcription 3 (STAT3) pathway, thereby inhibiting mitophagy, disrupting mitochondrial dynamics, promoting myocardial cell pyroptosis, and exacerbating I/R injury.

Advances in research on the impact and mechanisms of pathogenic microorganism infections on pyroptosis

Pyroptosis, also known as inflammatory necrosis, is a form of programmed cell death characterized by the activation of gasdermin proteins, leading to the formation of pores in the cell membrane, continuous cell swelling, and eventual membrane rupture. This process results in the release of intracellular contents, including pro-inflammatory cytokines like IL-1β and IL-18, which subsequently trigger a robust inflammatory response. This process is a crucial component of the body's innate immune response and plays a significant role in combating infections. There are four main pathways through which pathogenic microorganisms induce pyroptosis: the canonical inflammasome pathway, the non-canonical inflammasome pathway, the apoptosis-associated caspase-mediated pathway, and the granzyme-mediated pathway. This article provides a brief overview of the effects and mechanisms of pathogen infections on pyroptosis.

Causal association between cardiovascular risk factors and common skin diseases: A multivariate Mendelian randomization study

Cardiovascular diseases and dermatological conditions are prevalent health issues worldwide. Previous studies have suggested that risk factors for cardiovascular diseases may be associated with the development of dermatological conditions. However, the causal association between these factors remain unclear. This study utilized data from genome-wide association studies and applied Mendelian randomization (MR) to explore the potential causal association between cardiovascular risk factors and common dermatological conditions. Genetic variants significantly associated with low-density lipoprotein cholesterol (LDL-C), serum uric acid, blood glucose, and hypertension were selected as instrumental variables. We employed inverse variance weighted, MR Egger, and weighted mode methods for analysis. Sensitivity analyses, including Cochran Q test, MR-Egger intercept test, MR-PRESSO global test, and leave-one-out analysis, were conducted to ensure the robustness of the results. The MR analysis indicated a positive association between LDL-C levels and the risk of psoriasis (odds ratio [OR] = 1.23, 95% confidence interval [CI]: 1.03-1.47, P = .02). Additionally, hypertension and serum uric acid levels were positively associated with the risk of dermatitis eczema (hypertension: OR = 2.77, 95% CI: 1.23-6.24, P = .01; serum uric acid: OR = 1.09, 95% CI: 1.01-1.06, P = .01). This study provides evidence of a potential causal association between LDL-C levels and psoriasis, as well as between hypertension and serum uric acid levels and dermatitis eczema. These findings highlight the potential importance of cardiovascular health management in the prevention and treatment of common dermatological conditions. Further research is needed to validate these results and explore the underlying biological mechanisms.

Fucoidan from Laminaria japonica protects renal tubular epithelial cells from uric acid induced NLRP3-mediated pyroptosis through inhibition of NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Hyperuricemia is a common metabolic disease with prominent morbidity, it can lead to many adverse effects and complications, such as chronic nephrosis. Fucoidan has been used as natural drug for acute and chronic kidney disease for over 20 years in China, but the precise mechanisms underlying the renal protective function are still indefinable.

PURPOSE

This study is conducted to explore alleviation of fucoidan (FPS) from Laminaria japonica on urate-induced NOD-like receptor family, pyrin domain-containing 3 (NLRP3)-mediated pyroptosis in renal tubular epithelial cells HK-2, as well as the mechanism of nuclear factor κB (NF-κB) signaling pathway involved.

MATERIALS AND METHODS

HK-2 cells were treated with FPS, uric acid (UA), and inhibitor of NF-κB signaling pathway. Nitric oxide (NO) content and inducible nitric oxide synthase (iNOS) activity were determined with detection kits. Activation of intercellular NLRP3 inflammasome and NF-κB signaling pathway, gasdermin D (GSDMD) expression level were evaluated with Western blot and quantitative reverse transcription-PCR (qRT-PCR), and immunofluorescent analysis.

RESULTS

Data showed that UA induced cellular inflammatory response demonstrated by elevated NO content, iNOS activity and expression level of NLRP3 inflammasome-mediated pyroptosis associated molecules including NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), Caspase-1, interleukin 18 (IL-18) and GSDMD, moreover the NF-κB signaling pathway was activated by UA. However, FPS exposure inhibited efficiently the UA induced adverse effect.

CONCLUSION

It can be concluded that FPS inhibited UA-induced NLRP3-mediated pyroptosis in HK-2 cells through repressing NF-κB signaling pathway.

Tyrobp deficiency blocks NLRP3-mediated inflammation and pyroptosis to alleviate myocardial ischemia-reperfusion injury through regulating Syk

PURPOSE

The present study aims to investigate the biological function of Tyrobp in myocardial ischemia-reperfusion injury (MIRI) and to clarify its potential reaction mechanisms.

METHODS

AC16 cells were induced by oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate the MIRI in vitro. The cell transfection technology was used to downregulate Tyrobp, followed by assessment of cell damage, apoptosis and cytokines production via Cell Counting Kit (CCK)-8 assay, lactate dehydrogenase (LDH) release assay, TUNEL and ELISA assays, respectively. Immunofluorescence assay was performed to assess GSDMD. Corresponding proteins were detected via western blotting, and Co-immunoprecipitation (Co-IP) assay was used to validate proteins interaction.

RESULTS

Tyrobp was upregulated in OGD/R-exposed AC16 cells, and Tyrobp deficiency significantly alleviated OGD/R-caused cell viability loss, LDH release and cell apoptosis in AC16 cells. Meanwhile, Tyrobp deficiency inhibited the activation of NLRP3 inflammasome, reduced the production of cytokines and inhibited GSDMD intensity and GSDMD-N expression. Additionally, Tyrobp could interact with Syk and regulate Syk/NF-κB signaling. The rescue experiments showed that the above effects of Tyrobp deficiency on OGD/R-exposed AC16 cells were partly weakened by Syk overexpression.

CONCLUSION

Tyrobp deficiency alleviated MIRI by inhibiting NLRP3-mediated inflammation and pyroptosis through regulating Syk, providing a novel target for the treatment of MIRI.

Tryptophan Metabolism-Regulating Probiotics Alleviate Hyperuricemia by Protecting the Gut Barrier Integrity and Enhancing Colonic Uric Acid Excretion

The balance of gut microbiota affects uric acid synthesis and excretion, influencing the development of hyperuricemia. This study aimed to investigate the effects and mechanisms of probiotics on hyperuricemia and adenine- and potassium oxonate-induced colonic damage. After two months of gavage at 109 CFU/day, the probiotic strains Lactobacillus rhamnosus UA260 and Lactobacillus plantarum YU28, identified through in vitro screening, significantly reduced serum uric acid levels in hyperuricemia mice from 109.71 ± 56.33 to 38.76 ± 15.06 and 33.22 ± 6.91 μmol/L, respectively. These strains attenuated inflammatory, repaired gut barrier damage, and enhanced colonic uric acid transporter function, thereby promoting uric acid excretion. Furthermore, the probiotics significantly reshaped gut microbiota by increasing the abundance of beneficial bacteria, including Lactobacillus and Coprococcus, while modulating tryptophan, purine, and riboflavin metabolism. Changes in tryptophan metabolites, specifically indole-3-propionic acid and indole-3-acetic acid, were correlated with xanthine oxidase activity, colonic injury, and the expression of the uric acid transporter protein ABCG2 during treatment. Probiotics intervention activated aryl hydrocarbon receptor pathways. These findings suggest that probiotics alleviate hyperuricemia and colonic inflammatory by regulating gut microbiota composition and tryptophan microbial metabolite pathways. Probiotics that modulate tryptophan microbial metabolism may provide a potential strategy for treating or preventing hyperuricemia.

Targeted Delivery and ROS-Responsive Release of Lutein Nanoassemblies Inhibit Myocardial Ischemia-Reperfusion Injury by Improving Mitochondrial Function

Purpose

Myocardial ischemia-reperfusion injury (MI/RI) is associated with increased oxidative damage and mitochondrial dysfunction, resulting in an elevated risk of mortality. MI/RI may be alleviated by protecting cardiomyocytes from oxidative stress. Lutein, which belongs to a class of carotenoids, has proven to be effective in cardiovascular disease treatment due to its remarkable antioxidant properties, but its application is limited due to its poor stability and low bioavailability in vivo.

Methods

In this study, a delivery system was developed based on distearoyl phosphatidyl ethanolamine (DSPE)-thiol-ketone (TK)-PEG2K (polyethylene glycol 2000) (abbreviated as DTP) and PCM-SH (CWLSEAGPVVTVRALRGTGSW) to deliver lutein (abbreviated as lutein@DTPP) to damaged myocardium. First, lutein, lutein@DTP, or lutein@DTPP were injected through the tail vein once a day for 3 days and then MI/RI model rats were established by exposing rats to ischemia for 45 min and reperfusion for 6 h. We employed a range of experimental techniques including qRT-PCR, Western blotting, transmission electron microscopy, immunohistochemistry, immunofluorescence, flow cytometry, immunoprecipitation, molecular docking, and molecular dynamics simulations.

Results

Lutein@DTPP exhibited good myocardial targeting and ROS-responsive release. Our data suggested that lutein@DTPP effectively suppresses ferroptosis in cardiomyocytes. Mechanistically, we observed an upregulation of mouse double minute-2 (MDM2) in the hearts of MI/RI models and cardiomyocytes exposed to hypoxia/reoxygenation (H/R) conditions. In addition, NADH-ubiquinone oxidoreductase 75 kDa Fe-S protein 1 (NDUFS1) translocation from the cytosol to the mitochondria was inhibited by MDM2 upregulation. Notably, no significant variation in the total NDUFS1 expression was observed in H/R-exposed cardiomyocytes following treatment with siMDM2. Further study indicated that lutein facilitates the translocation of NDUFS1 from the cytosol to mitochondria by directly binding and sequestering MDM2, thereby improving mitochondrial function and inhibiting ferroptosis.

Conclusion

Lutein@DTPP promoted the mitochondrial translocation of NDUFS1 to restore mitochondrial function and inhibited the ferroptosis of cardiomyocytes by directly binding and sequestering MDM2.

Scutellarin: pharmacological effects and therapeutic mechanisms in chronic diseases

Scutellarin (SCU), a flavonoid glucuronide derived from Scutellaria barbata and Erigeron breviscapus, exhibits broad pharmacological effects with promising therapeutic potential in treating various chronic diseases. It has demonstrated efficacy in modulating multiple biological pathways, including antioxidant, anti-inflammatory, anti-apoptotic, and vasodilatory mechanisms. These protective roles make SCU a valuable compound in treating chronic diseases such as cerebrovascular diseases, cardiovascular diseases, neurodegenerative disorders, and metabolic diseases. Despite its multi-targeted effects, SCU faces challenges such as low bioavailability and limited clinical data, which hinder its widespread therapeutic application. Current research supports its potential to prevent oxidative stress, reduce inflammatory responses, and enhance cell survival in cells and rats. However, more comprehensive studies are required to clarify its molecular mechanisms and to develop strategies that enhance its bioavailability for clinical use. SCU could emerge as a potent therapeutic agent for the treatment of chronic diseases with complex pathophysiological mechanisms. This review examines the current literature on Scutellarin to provide a comprehensive understanding of its pharmacological activity, mechanisms of action, and therapeutic potential in treating chronic diseases.

Association of serum uric acid with all-cause and cardiovascular mortality in cardiovascular disease patients

The relationship between serum uric acid (SUA) and mortality in patients with cardiovascular disease (CVD) remains controversial. We aimed to explore the relationship between SUA and all-cause mortality (ACM) and cardiovascular mortality (CVM) in adult patients with CVD. This cohort study included 3977 patients with CVD from the National Health and Nutrition Examination Survey (2005-2018). Death outcomes were determined by linking National Death Index (NDI) records through December 31, 2019. We explored the association of SUA with mortality using weighted Cox proportional hazards regression models, subgroup analysis, Kaplan-Meier survival curves, weighted restricted cubic spline (RCS) models, and weighted threshold effect analysis among patients with CVD. During a median follow-up of 68 months (interquartile range, 34-110 months), 1,360 (34.2%) of the 3,977 patients with cardiovascular disease died, of which 536 (13.5%) died of cardiovascular deaths and 824 (20.7%) died of non-cardiovascular deaths. In a multivariable-adjusted model (Model 3), the risk of ACM (HR 1.38, 95% CI 1.16-1.64) and the risk of CVM (HR 1.39, 95% CI 1.04-1.86) for participants in the SUA Q4 group were significantly higher. In patients with CVD, RCS regression analysis revealed a nonlinear association (p < 0.001 for all nonlinearities) between SUA, ACM, and CVM in the overall population and in men. Subgroup analysis showed a nonlinear association between ACM and CVM with SUA in patients with CVD combined with chronic kidney disease (CKD), with thresholds of 5.49 and 5.64, respectively. Time-dependent ROC curves indicated areas under the curve of 0.61, 0.60, 0.58, and 0.55 for 1-, 3-, 5-, and 10-year survival for ACM and 0.69, 0.61, 0.59, and 0.56 for CVM, respectively. We demonstrate that SUA is an independent prognostic factor for the risk of ACM and CVM in patients with CVD, supporting a U-shaped association between SUA and mortality, with thresholds of 5.49 and 5.64, respectively. In patients with CVD combined with CKD, the association of the ACM and the CVM with SUA remains nonlinear.

The Role of Cardiac Macrophages in Inflammation and Fibrosis after Myocardial Ischemia-Reperfusion

According to current statistics, the mortality rate of cardiovascular diseases remains high, with coronary artery disease being the primary cause of death. Despite the widespread adoption of percutaneous coronary intervention (PCI) in recent years, which has led to a notable decrease in the mortality rate of myocardial infarction (MI), the pathological cardiac remodeling and heart failure that follow myocardial infarction still pose significant clinical challenges. Myocardial ischemia-reperfusion (MIR) injury represents a complex pathophysiological process, and the involvement of macrophages in this injury has consistently been a subject of significant focus. Following MIR, macrophages infiltrate, engulfing tissue debris and necrotic cells, and secreting pro-inflammatory factors. This initial response is crucial for clearing damaged tissue. Subsequently, the pro-inflammatory macrophages (M1) transition to an anti-inflammatory phenotype (M2), a shift that is essential for myocardial fibrosis and cardiac remodeling. This process is dynamic, complex, and continuous. To enhance understanding of this process, this review elaborates on the classification and functions of macrophages within the heart, covering recent research on signaling pathways involved in myocardial infarction through subsequent MIR injury and fibrosis. The ultimate aim is to reduce MIR injury, foster a conducive environment for cardiac recovery, and improve clinical outcomes for MI patients.

Oroxylin A alleviates myocardial ischemia-reperfusion injury by quelling ferroptosis via activating the DUSP10/MAPK-Nrf2 pathway

Reperfusion therapy is the primary treatment strategy for acute myocardial infarction (AMI). Paradoxically, it can lead to myocardial damage, namely myocardial ischemia/reperfusion injury (MIRI). This study explored whether oroxylin A (OA) protects the myocardium after MIRI by inhibiting ferroptosis and the underlying mechanism. In vivo, we established an MIRI model to investigate the protective effect of OA. In vitro, H9C2 cells were used to explore the regulation of ferroptosis by OA through immunofluorescence staining, western blotting, assay kits, etc. Additionally, RNA sequencing analysis (RNA-seq) and network pharmacology analyses were conducted to elucidate the molecular mechanisms. Our results showed that MIRI caused cardiac structural and functional damage in rats. MIRI promoted ferroptosis, which was consistently observed in vitro. However, pretreatment with OA reversed these effects. The mitogen-activated protein kinases (MAPK) signaling pathway participated in the MIRI process, with dual-specificity phosphatase 10 (DUSP10) found to regulate it. Further confirmation was provided by knocking down DUSP10 using small interfering RNA (siRNA), demonstrating the activation of the DUSP10/MAPK-Nrf2 pathway by OA to protect H9C2 cells from ferroptosis. Our research has demonstrated the mitigating effect of OA on MIRI and the improvement of myocardial function for the first time. The inhibition of ferroptosis has been identified as one of the mechanisms through which OA exerts its myocardial protective effects. Moreover, we have first unveiled that DUSP10 serves as an upstream target involved in mediating ferroptosis, and the regulation of the DUSP10/MAPK-Nrf2 pathway by OA is crucial in inhibiting ferroptosis to protect the myocardium.

Oxidative Stress and Inflammation in Myocardial Ischemia-Reperfusion Injury: Protective Effects of Plant-Derived Natural Active Compounds

Acute myocardial infarction (AMI) remains a leading cause of death among patients with cardiovascular diseases. Percutaneous coronary intervention (PCI) has been the preferred clinical treatment for AMI due to its safety and efficiency. However, research indicates that the rapid restoration of myocardial oxygen supply following PCI can lead to secondary myocardial injury, termed myocardial ischemia-reperfusion injury (MIRI), posing a grave threat to patient survival. Despite ongoing efforts, the mechanisms underlying MIRI are not yet fully elucidated. Among them, oxidative stress and inflammation stand out as critical pathophysiological mechanisms, playing significant roles in MIRI. Natural compounds have shown strong clinical therapeutic potential due to their high efficacy, availability, and low side effects. Many current studies indicate that natural compounds can mitigate MIRI by reducing oxidative stress and inflammatory responses. Therefore, this paper reviews the mechanisms of oxidative stress and inflammation during MIRI and the role of natural compounds in intervening in these processes, aiming to provide a basis and reference for future research and development of drugs for treating MIRI.

Hyperuricaemia elevates risk of short-term readmission and mortality in patients with heart failure

BACKGROUND

Heart failure (HF) is a leading cause of morbidity and mortality worldwide. Serum uric acid (SUA), a product of purine metabolism, has been implicated in HF progression. However, the association between hyperuricaemia and the short-term readmission and mortality in patients with HF remains controversial.

METHODS

In this retrospective cohort study, we analysed data from a HF database specific to the Chinese population. The primary endpoint was short-term readmission or all-cause mortality within 90 days. Participants with HF were categorised into normouricaemia group (NUA) and hyperuricaemia group (HUA) based on a SUA threshold of 420 µmol/L. The association between SUA and primary endpoint was evaluated using Kaplan-Meier survival curves and Cox regression analysis.

RESULTS

Baseline characteristics revealed significant differences between NUA and HUA groups, with the latter exhibiting a higher prevalence of males, chronic kidney disease (CKD) and elevated levels of various biomarkers. During a 90-day follow-up, 493 (26.6%) participants reached the primary endpoint, with a higher incidence observed in the HUA group at 31.2%, compared with 20.1% in the NUA group. When a threshold effect was identified at 420 µmol/L, a non-linear association was observed between SUA and the primary endpoint. After adjusting for gender, age, New York Heart Association class, CKD, systolic blood pressure (SBP) and potassium, the HUA group exhibited a higher risk for the primary endpoint compared with the NUA group (HR: 1.40, 95% CI: 1.14 to 1.72, p=0.001). Additionally, the risk increased across quartiles of SUA (P for trend=0.002). Furthermore, stratified analyses indicated a stronger association in patients without CKD (P interaction=0.033).

CONCLUSION

Hyperuricaemia is independently associated with an increased risk of short-term readmission and mortality in patients with HF. Our findings suggest that monitoring and managing SUA could be crucial in improving patient with HF outcomes.

Pyroptosis: An Accomplice in the Induction of Multisystem Complications Triggered by Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common respiratory disorder, primarily characterized by two pathological features: chronic intermittent hypoxia (CIH) and sleep deprivation (SD). OSA has been identified as a risk factor for numerous diseases, and the inflammatory response related to programmed cell necrosis is believed to play a significant role in the occurrence and progression of multisystem damage induced by OSA, with increasing attention being paid to pyroptosis. Recent studies have indicated that OSA can elevate oxidative stress levels in the body, activating the process of pyroptosis within different tissues, ultimately accelerating organ dysfunction. However, the molecular mechanisms of pyroptosis in the multisystem damage induced by OSA remain unclear. Therefore, this review focuses on four major systems that have received concentrated attention in existing research in order to explore the role of pyroptosis in promoting renal diseases, cardiovascular diseases, neurocognitive diseases, and skin diseases in OSA patients. Furthermore, we provide a comprehensive overview of methods for inhibiting pyroptosis at different molecular levels, with the goal of identifying viable targets and therapeutic strategies for addressing OSA-related complications.

Uric acid is associated with increased risk of myocardial infarction: results from NHANES 2009-2018 and bidirectional two-sample Mendelian randomization analysis

Aim

Although a growing number of studies have shown that elevated uric acid (UA) levels are associated with multiple cardiovascular risk factors and progression of coronary artery disease, the causal relationship between UA and the occurrence of myocardial infarction (MI) remains uncertain. The aim of this study was to investigate the relationship between UA and the risk of MI.

Methods

We screened 23,080 patients in the National Health and Nutrition Examination Survey (NHANES) database for 2009-2018 and explored the association between UA and MI risk using multivariate logistic regression model. In addition, a two-way two-sample Mendelian randomization (TSMR) analysis was performed to examine the causal relationship of UA on MI, and inverse variance-weighted (IVW) results were used as the primary outcome in this study. Sensitivity analysis and horizontal multiple validity test were also performed to verify the reliability of the results.

Results

After multivariable adjustment, individuals with the severe elevation of UA levels have a significantly increased risk of MI (OR=2.843, 95%CI: 1.296-6.237, P=0.010). In TSMR analysis, the IVW method demonstrated a significant association between UA and increased risk of MI (OR=1.333, 95%CI: 1.079-1.647, P=0.008). Results from the MR-Egger intercept test, Cochran's Q test, and MR-PRESSO test all suggest the reliability of the IVW analysis. Reverse TSMR analysis did not indicate a causal relationship between genetic susceptibility to MI and UA levels (IVW: OR=1.001, 95%CI: 0.989-1.012, P=0.922).

Conclusion

Based on cross-sectional study and Mendelian randomization analysis, it has been demonstrated that UA is an independent risk factor for MI. Elevated levels of UA increase the risk of MI, particularly in cases of severe elevation.

Interference with GPR4 inactivates NLRP3 inflammasome signaling by inhibiting LPAR1 expression to ameliorate oxygen-glucose deprivation/reoxygenation-induced inflammation and apoptosis of cardiomyocytes

Myocardial ischemia/reperfusion (MI/R) injury is a detrimental disease with high mortality worldwide. We aimed to explore the role of G protein-coupled receptor 4 (GPR4) and lysophosphatidic acid receptor 1 (LPAR1) in MI/R injury in vitro. H9c2 cells were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) conditions to simulate the MI/R injury and GPR4 expression was detected. Then, GPR4 was knocked down and cell viability was examined with a CCK-8 assay. The activities of LDH, CK and CK-MB were detected to evaluate the damage of OGD/R-induced H9c2 cells. ELISA kits and TUNEL staining were used to examine the inflammation and apoptosis of H9c2 cells exposed to OGD/R conditions. Western blot was employed to detect the expression of proteins related to apoptosis and NLRP3 inflammasome signaling. Additionally, Co-IP analyzed the binding between GPR4 and LPAR1. Finally, LPAR1 was overexpressed to conduct the rescue experiments. Results revealed that GPR4 was upregulated in OGD/R-treated H9c2 cells and GPR4 knockdown attenuated the damage of H9c2 cells. OGD/R induced inflammation and apoptosis were markedly inhibited by GPR4 silencing, as evidenced by the decreased TNF-α, IL-6 and IL-8 levels as well as the elevated Bcl-2 expression and reduced Bax and cleaved caspase3 expression. Moreover, GPR4 bound to LPAR1 and upregulated LPAR1 expression. Interference with GPR4 inactivated the NLRP3 inflammasome signaling. Besides, LPAR1 overexpression abrogated the effects of GPR4 silencing on the damage, inflammation and apoptosis of H9c2 cells induced by OGD/R. Particularly, LPAR1 upregulation promoted the activation of NLRP3 inflammasome signaling in GPR4-silenced H9c2 cells induced by OGD/R. To be concluded, GPR4 deficiency inactivates NLRP3 inflammasome signaling by inhibiting LPAR1 expression to ameliorate OGD/R -induced inflammation and apoptosis of cardiomyocytes.

ACE2 Alleviates Endoplasmic Reticulum Stress and Protects against Pyroptosis by Regulating Ang1-7/Mas in Ventilator-Induced Lung Injury

BACKGROUND

Ventilator-induced lung injury (VILI) is a consequence of inflammation and increased alveolar-capillary membrane permeability due to alveolar hyperdistention or elevated intrapulmonary pressure, but the precise mechanisms remain unclear. The aim of the study was to analyze the mechanism by which angiotensin converting enzyme 2 (ACE2) alleviates endoplasmic reticulum stress (ERS) and protects alveolar cells from pyroptosis in VILI by regulating angiotensin (Ang)1-7/Mas.

METHODS

VILI was induced in mice by mechanical ventilation by regulating the tidal volume. The alveolar cell line, A549, mimics VILI in vitro by cyclic stretch (CS). Ang (1-7) (100 nmol/L) was added to the medium. ERS was induced in cells by stimulating with tunicamycin (TM, 2 μg/mL). ERS was inhibited by tracheal instillation of 4-phenylbutyric acid (4-PBA) (1 mg/kg). ACE2's enzymatic function was activated or inhibited by subcutaneous injection of resorcinolnaphthalein (RES, 20 μg/kg) or MLN-4760 (20 μg/kg). pGLV-EF1a-GFP-ACE2 was instilled into the trachea to increase the protein expression of ACE2. The Ang (1-7) receptor, Mas, was antagonized by injecting A779 subcutaneously (80 μg/kg).

RESULTS

ACE2 protein levels decreased after modeling. Ang (1-7) level was decreased and Ang II was accumulated. ERS was significantly induced in VILI mice, and pyroptosis was observed in cells. When ERS was inhibited, pyroptosis under the VILI condition was significantly inhibited. Ang (1-7) alleviated ERS and pyroptosis under CS. When ERS was continuously activated, the function of Ang (1-7) in inhibiting pyroptosis was blocked. Resorcinolnaphthalein (RES) effectively promoted Ang II conversion, alleviated the Ang (1-7) level in VILI, ameliorated lung injury, and inhibited ERS and cell pyroptosis. Inhibiting ACE2's function in VILI hindered the production of Ang (1-7), promoted the accumulation of Ang II, and exacerbated ERS and pyroptosis, along with lung injury. The Mas antagonist significantly blocked the inhibitory effects of ACE2 on ERS and pyroptosis in VILI.

CONCLUSIONS

Reduced ACE2 expression in VILI is involved in ERS and pyroptosis-related injury. ACE2 can alleviate ERS in alveolar cells by catalyzing the production of Ang (1-7), thus inhibiting pyroptosis in VILI.

Pyroptosis in health and disease: mechanisms, regulation and clinical perspective

Pyroptosis is a type of programmed cell death characterized by cell swelling and osmotic lysis, resulting in cytomembrane rupture and release of immunostimulatory components, which play a role in several pathological processes. Significant cellular responses to various stimuli involve the formation of inflammasomes, maturation of inflammatory caspases, and caspase-mediated cleavage of gasdermin. The function of pyroptosis in disease is complex but not a simple angelic or demonic role. While inflammatory diseases such as sepsis are associated with uncontrollable pyroptosis, the potent immune response induced by pyroptosis can be exploited as a therapeutic target for anti-tumor therapy. Thus, a comprehensive review of the role of pyroptosis in disease is crucial for further research and clinical translation from bench to bedside. In this review, we summarize the recent advancements in understanding the role of pyroptosis in disease, covering the related development history, molecular mechanisms including canonical, non-canonical, caspase 3/8, and granzyme-mediated pathways, and its regulatory function in health and multiple diseases. Moreover, this review also provides updates on promising therapeutic strategies by applying novel small molecule inhibitors and traditional medicines to regulate pyroptosis. The present dilemmas and future directions in the landscape of pyroptosis are also discussed from a clinical perspective, providing clues for scientists to develop novel drugs targeting pyroptosis.

Escin alleviates cerebral ischemia-induced intestinal pyroptosis via the GR-dependent p38 MAPK/NF-κB signaling and NLRP3 inflammasome activation

Cerebral ischemia-induced systemic inflammation and inflammasome-dependent pyroptotic cell death in ileum, causing serious intestinal injury. Glucocorticoid receptor (GR) mediates the effects of glucocorticoids and participates in inflammation. Escin has corticosteroid-like, neuroprotective, and anti-intestinal dysfunction effects. This study aimed to investigate the effect of Escin on the intestinal barrier injury in rats subjected to middle cerebral artery occlusion (MCAO) and on Caco-2 cells exposed to lipopolysaccharides. The MCAO-caused brain injury was evaluated by assessing neurological function, cerebral infarct volume, and plasma corticosterone (Cort) levels. Intestinal injury was evaluated by observing the histopathological changes, assessing the intestinal barrier function, and determining blood FD4, endotoxin and IL-1β levels. The levels of the tight-junction proteins such as claudin-1, occludin, and ZO-1, and proteins involved in the GR/p38 MAPK/NF-κB pathway and NLRP3-inflammasome activation were evaluated using western blotting or immunofluorescence. Administration of Escin suppressed the cerebral ischemia-induced increases in Garcia-test scores and infarct volume, alleviated the injury to the intestinal barrier, and decreased the levels of Cort, endotoxin, and IL-1β. Additionally, Escin upregulated GR and downregulated phospho(p)-p65, p-p38MAPK, NLRP3, GSDMD-N, and cleaved-caspase-1 in the intestine. The effects of Escin could be suppressed by the GR antagonist RU486 or enhanced by the p38 MAPK antagonist SB203580. We revealed details how Escin improves cerebral ischemia-induced intestinal barrier injury by upregulating GR and thereby inhibiting the pyroptosis induced by NF-κB-mediated NLRP3 activation. This study will provide a experimental foundation for the features of glucocorticoid-like activity and the discovery of new clinical application for Escin.

A new insight into the mechanism of dichlorodiphenyltrichloroethane-induced hepatotoxicity based on GSDME-mediated pyroptosis

There have been persistent concerns about the safety risks associated with DDT residues in the environment. Studies have shown that exposure to DDT or its metabolites can cause various liver diseases. However, the mechanisms of liver toxicity haven't been well studied. In our current investigation, we observed that DDT triggers pyroptosis in human liver cells (HL-7702), representing a novel form of programmed cell death. Our results delineated DDT (0-100 μM) induced pyroptosis in HL-7702 cells, which was confirmed through morphological changes, lactate dehydrogenase (LDH) release, gasdermin E (GSDME) cleavage and Annexin-V/PI staining. Knockdown of GSDME reduced cell death and transferred the mode of cell death from pyroptosis to apoptosis. Notably, DDT exposure markedly increased reactive oxygen species (ROS) production, concurrent with c-Jun N-terminal kinase (JNK) phosphorylation. Intervention with a ROS inhibitor or JNK inhibitor SP600125 restored cell viability and hindered GSDME-mediated pyroptosis. Our results firstly demonstrate that DDT suppresses HL-7702 cells growth by inducing pyroptosis mainly through the ROS/JNK/GSDME pathway. These findings not only contribute to an in-depth understanding of DDT toxicity but also open avenues for gaining valuable insights into potential mitigation strategies and therapeutic interventions.

Hyperuricemia and its related diseases: mechanisms and advances in therapy

Hyperuricemia, characterized by elevated levels of serum uric acid (SUA), is linked to a spectrum of commodities such as gout, cardiovascular diseases, renal disorders, metabolic syndrome, and diabetes, etc. Significantly impairing the quality of life for those affected, the prevalence of hyperuricemia is an upward trend globally, especially in most developed countries. UA possesses a multifaceted role, such as antioxidant, pro-oxidative, pro-inflammatory, nitric oxide modulating, anti-aging, and immune effects, which are significant in both physiological and pathological contexts. The equilibrium of circulating urate levels hinges on the interplay between production and excretion, a delicate balance orchestrated by urate transporter functions across various epithelial tissues and cell types. While existing research has identified hyperuricemia involvement in numerous biological processes and signaling pathways, the precise mechanisms connecting elevated UA levels to disease etiology remain to be fully elucidated. In addition, the influence of genetic susceptibilities and environmental determinants on hyperuricemia calls for a detailed and nuanced examination. This review compiles data from global epidemiological studies and clinical practices, exploring the physiological processes and the genetic foundations of urate transporters in depth. Furthermore, we uncover the complex mechanisms by which the UA induced inflammation influences metabolic processes in individuals with hyperuricemia and the association with its relative disease, offering a foundation for innovative therapeutic approaches and advanced pharmacological strategies.

Genetic liability to human serum metabolites is causally linked to telomere length: insights from genome-wide Mendelian randomization and metabolic pathways analysis

Background

Telomere has been recognized as a biomarker of accelerating aging, and telomere length (TL) shortening is closely related to diverse chronic illnesses. Human serum metabolites have demonstrated close correlations with TL maintenance or shortening in observational studies. Nevertheless, little is known about the underlying pathological mechanisms, and Mendelian randomization (MR) analysis of serum metabolites may provide a more comprehensive understanding of the potential biological process.

Methods

We employed a two-sample MR analysis method to assess the causal links between 486 serum metabolites and TL. We applied the inverse-variance weighted (IVW) approach as our primary analysis, and to assure the stability and robustness of our results, additional analysis methods including the weighted median, MR-Egger, and weighted mode were conducted. MR-Egger intercept test was utilized to detect the pleiotropy. Cochran's Q test was implemented to quantify the extent of heterogeneity. Furthermore, the pathway analysis was conducted to identify potential metabolic pathways.

Results

We identified 11 known blood metabolites associated with TL. Among these metabolites, four were lipid (taurocholate, dodecanedioate, 5,8-tetradecadienoate, and 15-methylpalmitate), one amino acid (levulinate (4-oxovaleate)), one carbohydrate (lactate), one nucleotide (pseudouridine), one energy (phosphate), and three xenobiotics (2-hydroxyacetaminophen sulfate, paraxanthine, and ergothioneine). The known protective metabolites included levulinate (4-oxovaleate), dodecanedioate, 5,8-tetradecadienoate, lactate, phosphate, paraxanthine, and ergothioneine. Multiple metabolic pathways have been identified as being implicated in the maintenance of telomere length.

Conclusion

Our MR analysis provided suggestive evidence supporting the causal relationships between 11 identified blood metabolites and TL, necessitating further exploration to clarify the mechanisms by which these serum metabolites and metabolic pathways may affect the progression of telomeres.

Inhibitors of NLRP3 Inflammasome Formation: A Cardioprotective Role for the Gasotransmitters Carbon Monoxide, Nitric Oxide, and Hydrogen Sulphide in Acute Myocardial Infarction

Myocardial ischaemia reperfusion injury (IRI) occurring from acute coronary artery disease or cardiac surgical interventions such as bypass surgery can result in myocardial dysfunction, presenting as, myocardial "stunning", arrhythmias, infarction, and adverse cardiac remodelling, and may lead to both a systemic and a localised inflammatory response. This localised cardiac inflammatory response is regulated through the nucleotide-binding oligomerisation domain (NACHT), leucine-rich repeat (LRR)-containing protein family pyrin domain (PYD)-3 (NLRP3) inflammasome, a multimeric structure whose components are present within both cardiomyocytes and in cardiac fibroblasts. The NLRP3 inflammasome is activated via numerous danger signals produced by IRI and is central to the resultant innate immune response. Inhibition of this inherent inflammatory response has been shown to protect the myocardium and stop the occurrence of the systemic inflammatory response syndrome following the re-establishment of cardiac circulation. Therapies to prevent NLRP3 inflammasome formation in the clinic are currently lacking, and therefore, new pharmacotherapies are required. This review will highlight the role of the NLRP3 inflammasome within the myocardium during IRI and will examine the therapeutic value of inflammasome inhibition with particular attention to carbon monoxide, nitric oxide, and hydrogen sulphide as potential pharmacological inhibitors of NLRP3 inflammasome activation.

Targeted H2S-Mediated Gas Therapy with pH-Sensitive Release Property for Myocardial Ischemia-Reperfusion Injury by Platelet Membrane

Management of myocardial ischemia-reperfusion injury (MIRI) in reperfusion therapy remains a major obstacle in the field of cardiovascular disease, but current available therapies have not yet been achieved in mitigating myocardial injury due to the complex pathological mechanisms of MIRI. Exogenous delivery of hydrogen sulfide (H2S) to the injured myocardium can be an effective strategy for treating MIRI due to the multiple physiologic functions of H2S, including anti-inflammatory, anti-apoptotic, and mitochondrial protective effects. Here, to realize the precise delivery and release of H2S, we proposed the targeted H2S-mediated gas therapy with pH-sensitive release property mediated by platelet membranes (PMs). In this study, a biomimetic functional poly(lactic-co-ethanolic acid) nanoparticle (RAPA/JK-1-PLGA@PM) was fabricated by loading rapamycin (RAPA; mTOR inhibitor) and JK-1 (H2S donor) and then coated with PM. In vitro observations were conducted including pharmaceutical evaluation, H2S release behaviors, hemolysis analysis, serum stability, cellular uptake, cytotoxicity, inhibition of myocardial apoptosis, and anti-inflammation. In vivo examinations were performed including targeting ability, restoration of cardiac function, inhibition of pathological remodeling, and anti-inflammation. RAPA/JK-1-PLGA@PM was successfully prepared with good size distribution and stability. Utilizing the natural infarct-homing ability of PM, RAPA/JK-1-PLGA@PM could be effectively targeted to the damaged myocardium. RAPA/JK-1-PLGA@PM continuously released H2S triggered by inflammatory microenvironment, which could inhibit cardiomyocyte apoptosis, realize the transition of pro-inflammation, and alleviate myocardial injury demonstrated in hypoxia/reoxygenation myocardial cell in vitro. Precise delivery and release of H2S attenuated inflammatory response and cardiac damage, promoted cardiac repair, and ameliorated cardiac function proven in MIRI mouse model in vivo. This research outlined the novel nanoplatform that combined immunosuppressant agents and H2S donor with the pH-sensitive release property, offering a promising therapeutic for MIRI treatment that leveraged the synergistic effects of gas therapy.

The interplay between T lymphocytes and macrophages in myocardial ischemia/reperfusion injury

Acute myocardial infarction is one of the most important causes of death in the world, causing a huge health and economic burden to the world. It is still a ticklish problem how to effectively prevent reperfusion injury while recovering the blood flow of ischemic myocardium. During the process of myocardial ischemia/reperfusion injury (MI/RI), the modulation of immune cells plays an important role. Monocyte/macrophage, neutrophils and endothelial cells initiate the inflammatory response and induce the release of various inflammatory cytokines, resulting in increased vascular permeability, tissue edema and damage. Meanwhile, T cells were recruited to impaired myocardium and release pro-inflammatory and anti-inflammatory cytokines. T cells and macrophages play important roles in keeping cardiac homeostasis and orchestrate tissue repair. T cells differentiation and macrophages polarization precisely regulates the tissue microenvironment in MI/RI, and shows cross action, but the mechanism is unclear. To identify potential intervention targets and propose ideas for treatment and prevention of MI/RI, this review explores the crosstalk between T lymphocytes and macrophages in MI/RI.

Enhanced Cardiomyocyte NLRP3 Inflammasome-Mediated Pyroptosis Promotes d-Galactose-Induced Cardiac Aging

BACKGROUND

Cardiac aging represents an independent risk factor for aging-associated cardiovascular diseases. Although evidence suggests an association between NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome formation and numerous cardiovascular diseases, its role in cardiac aging remains largely unclear.

METHODS AND RESULTS

The longevity of mice with wild-type and NLRP3 knockout (NLRP3-/-) genotypes was assessed, with or without d-galactose treatment. Cardiac function was evaluated using echocardiography, and cardiac histopathology was examined through hematoxylin and eosin and Masson's trichrome staining. Senescence-associated β-galactosidase (SA-β-gal) staining was employed to detect cardiac aging. Western blotting was used to assess aging-related proteins (p53, p21) and pyroptosis-related proteins. Additionally, dihydroethidium staining, lactate dehydrogenase release, and interleukin-1β ELISA assays were performed, along with measurements of total superoxide dismutase and malondialdehyde levels. In vitro, H9c2 cells were exposed to d-galactose for 24 hours in the absence or presence of N-acetyl-l-cysteine (reactive oxygen species inhibitor), BAY-117082 (nuclear factor κ-light-chain enhancer of activated B cells inhibitor), MCC950 (NLRP3 inhibitor), and VX-765 (Caspase-1 inhibitor). Immunofluorescence staining was employed to detect p53, gasdermin D, and apoptosis-associated speck-like protein proteins. Intracellular reactive oxygen species levels were assessed using fluorescence microscopy and flow cytometry. Senescence-associated β-galactosidase staining and Western blotting were also employed in vitro for the same purpose. The results showed that NLRP3 upregulation was implicated in aging and cardiovascular diseases. Inhibition of NLRP3 extended life span, mitigated the aging phenotype, improved cardiac function and blood pressure, ameliorated lipid metabolism abnormalities, inhibited pyroptosis in cardiomyocytes, and ultimately alleviated cardiac aging. In vitro, the inhibition of reactive oxygen species, nuclear factor κ-light-chain enhancer of activated B cells, NLRP3, or caspase-1 attenuated NLRP3 inflammasome-mediated pyroptosis.

CONCLUSIONS

The reactive oxygen species/nuclear factor κ-light-chain enhancer of activated B cells/NLRP3 signaling pathway loop contributes to d-galactose-treated cardiomyocyte senescence and cardiac aging.

Alpha-cyperone mitigates renal ischemic injury via modulation of HDAC-2 expression in diabetes: Insights from molecular dynamics simulations and experimental evaluation

Chronic diabetes mellitus is reported to be associated with acute kidney injury. The enzyme histone deacetylase-2 (HDAC-2) was found to be upregulated in diabetes-related kidney damage. Alpha-cyperone (α-CYP) is one of the active ingredients of Cyperus rotundus that possesses antioxidant and anti-inflammatory effects. We evaluated the effect of α-CYP on improving oxidative stress and tissue inflammation following renal ischemia/reperfusion (I/R) injury in diabetic rats. The effect of α-CYP on HDAC-2 expression in renal homogenates and in the NRK-52 E cell line was evaluated following renal I/R injury and high glucose conditions, respectively. Molecular docking was used to investigate the binding of α-CYP with the HDAC-2 active site. Both renal function and oxidative stress were shown to be impaired in diabetic rats due to renal I/R injury. Significant improvements in kidney/body weight ratio, creatinine clearance, serum creatinine, blood urea nitrogen (BUN), and uric acid were observed in diabetic rats treated with α-CYP (50 mg/kg) two weeks prior to renal I/R injury. α-CYP treatment also improved histological alterations in renal tissue and lowered levels of malondialdehyde, myeloperoxidase, and hydroxyproline. Treatment with α-CYP suppressed the increased HDAC-2 expression in the renal tissue of diabetic rats and in the NRK-52 E cell line. The molecular docking reveals that α-CYP binds to HDAC-2 with good affinity, ascertained by molecular dynamics simulations and binding free energy analysis. Overall, our data suggest that α-CYP can effectively prevent renal injury in diabetic rats by regulating oxidative stress, tissue inflammation, fibrosis and inhibiting HDAC-2 activity.

Activation of PPAR-α attenuates myocardial ischemia/reperfusion injury by inhibiting ferroptosis and mitochondrial injury via upregulating 14-3-3η

This study aimed to explore the effects of peroxisome proliferator-activated receptor α (PPAR-α), a known inhibitor of ferroptosis, in Myocardial ischemia/reperfusion injury (MIRI) and its related mechanisms. In vivo and in vitro MIRI models were established. Our results showed that activation of PPAR-α decreased the size of the myocardial infarct, maintained cardiac function, and decreased the serum contents of creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and Fe2+ in ischemia/reperfusion (I/R)-treated mice. Additionally, the results of H&E staining, DHE staining, TUNEL staining, and transmission electron microscopy demonstrated that activation of PPAR-α inhibited MIRI-induced heart tissue and mitochondrial damage. It was also found that activation of PPAR-α attenuated MIRI-induced ferroptosis as shown by a reduction in malondialdehyde, total iron, and reactive oxygen species (ROS). In vitro experiments showed that intracellular contents of malondialdehyde, total iron, LDH, reactive oxygen species (ROS), lipid ROS, oxidized glutathione disulphide (GSSG), and Fe2+ were reduced by the activation of PPAR-α in H9c2 cells treated with anoxia/reoxygenation (A/R), while the cell viability and GSH were increased after PPAR-α activation. Additionally, changes in protein levels of the ferroptosis marker further confirmed the beneficial effects of PPAR-α activation on MIRI-induced ferroptosis. Moreover, the results of immunofluorescence and dual-luciferase reporter assay revealed that PPAR-α achieved its activity via binding to the 14-3-3η promoter, promoting its expression level. Moreover, the cardioprotective effects of PPAR-α could be canceled by pAd/14-3-3η-shRNA or Compound C11 (14-3-3η inhibitor). In conclusion, our results indicated that ferroptosis plays a key role in aggravating MIRI, and PPAR-α/14-3-3η pathway-mediated ferroptosis and mitochondrial injury might be an effective therapeutic target against MIRI.

Protective effects of 4-methylumbelliferone on myocardial ischemia/reperfusion injury in rats through inhibition of oxidative stress and downregulation of TLR4/NF-κB/NLRP3 signaling pathway

Myocardial ischemia-reperfusion injury (MI/R) has been found to be one of the important risk factors for global cardiac mortality and morbidity. The study was conducted to inquire into the protective effect of 4-methylumbilliferon (4-MU) against MI/R in rats and clarify its potential underlying mechanism. Animals were divided into four groups (n = 15) including sham, MI/R, MI/R + vehicle, and MI/R + 4-MU. MI/R was established in Wistar rats by occluding the left anterior descending (LAD) coronary artery for 30 min. 4-MU (25 mg/kg) was injected intraperitoneally before the induction of reperfusion. Cardiac function, fibrosis, oxidant/antioxidant markers, and inflammatory cytokines were evaluated using echocardiography, ELISA, and Western blot assay. As a result of MI/R induction, a decrease in left ventricular contractile function occurred along with increased cardiac fibrosis and tissue damage. The serum levels of TNF-α, IL-1β, and IL-18 increased, while IL-10 decreased. Oxidant/antioxidant changes were evident with increased MDA levels and decreased GSH, SOD, and CAT in the MI/R group. Furthermore, the protein levels of TLR4, NF-κB, and NLRP3 were significantly increased in the heart tissue of MI/R group. Treatment with 4-MU significantly prevented the reduction of cardiac contractile function and its pathological changes as a result of MI/R by inhibiting the increase of serum inflammatory factors and improving the oxidant/antioxidant balance probably through the TLR4/NF-κB/NLRP3 axis. The results of a current study showed that 4-MU had a potential ability to attenuate the cardiac injury by reducing oxidative stress and inflammation in a TLR4/NF-κB/NLRP3-dependent mechanism.