GRK2 participation in cardiac hypertrophy induced by isoproterenol through the regulation of Nrf2 signaling and the promotion of NLRP3 inflammasome and oxidative stress

Effects of Dictyophora polysaccharide on cerebellar Purkinje cell degeneration in a chronic alcohol mouse model

BACKGROUND

Recent research showed that the NLRP3 inflammasome was activated in the central nervous system of mice administered chronic ethanol (EtOH). Dictyophora polysaccharides (DIPs) are essential components of the valuable edible fungus Dictyophora, which has antioxidant properties that can delay the aging process of the body. This study aimed to investigate the roles of NLRP3 in chronic EtOH-induced cerebellar Purkinje cell (PC) degeneration and behavioral changes.

METHODS

C57BL/6J normal and NLRP3 knockout mice were exposed to EtOH for 14 days. Dictyophora polysaccharide (DIP) and NLRP3 inhibitor were administered to the EtOH mice. The pathology and NLRP3-ASC-caspase-1 signaling pathway proteins were analyzed in EtOH mice cerebellar tissues and behavioral performance was assessed in the mice.

RESULTS

In the EtOH mouse model, we observed increases in the NLRP3 inflammasome proteins, including NLRP3, ASC, caspase-1, mature IL-1β and pro IL-1β, loss of PCs, and motor coordination disorders. We found that DIPs could suppress the NLRP3-ASC-caspase-1 signaling pathway, and alleviate the motor deficits and cerebellar pathological changes in chronic EtOH mice. Next, we used MCC950, a NLRP3 inhibitor, and an NLRP3 knockout strategy to further verify the effects of NLRP3-ASC-caspase-1 signaling in chronic EtOH mice. MCC950 or NLRP3 knockout alleviated the EtOH-induced latency to decreases in fall time, increases in stride width and decreases in stride length. MCC950 or NLRP3 knockout also attenuated PC number loss and suppressed NLRP3 inflammation induced by EtOH. Taken together, pharmacologically or genetically inhibiting NLRP3 alleviated EtOH-induced cerebellar degeneration and behavioral deficits.

CONCLUSION

These findings indicated that DIPs might diminish EtOH-induced cerebellar degeneration and behavioral deficits through the NLRP3-ASC-caspase-1 signaling pathway, which provides a potential therapeutic target for the prevention and treatment of alcoholism and EtOH-induced cerebellar pathology.

Icariin improves erectile function in spontaneously hypertensive rats by downregulating GRK2 in penile cavernous tissue

BACKGROUND

Hypertension is an independent risk factor for erectile dysfunction (ED). Icariin can improve erectile function of spontaneous hypertensive rats (SHRs). GRK2 is closely related to the phosphorylation of eNOS and endothelial function.

AIM

To explore whether icariin can improve erectile function in SHRs by regulating the expression of GRK2 in penile cavernous tissue.

METHODS

Eight-week-old WKY and SHR rats were randomly divided into four groups (n = 6 per group) as follows: WKY, WKY + icariin, SHR and SHR + icariin. The WKY + icariin and SHR + icariin groups were treated with 10 mg/kg/day icariin. After 4 weeks, the ICPmax/mean arterial pressure (MAP), serum testosterone, the levels of GRK2, p-AKT/AKT, p-eNOS/eNOS, and caspase-3; the protein interaction between GRK2 and AKT; the levels of nitric oxide (NO), superoxide dismutase (SOD), and malondialdehyde (MDA); and the level of apoptosis in rat penile cavernous tissue were measured.

OUTCOME

The expression of GRK2 in penile cavernous tissue of SHR was significantly higher than that in WKY rats, resulting in the inhibition of the AKT/eNOS/NO pathway, increased levels of oxidative stress and apoptosis, and the impairment of erectile function.

RESULTS

The ICPmax/MAP ratio in the SHR group was significantly lower than those in WKY and SHR + icariin groups (P < .01). In the SHR + icariin group, the expression levels of GRK2 and caspase-3, the interaction between GRK2 and AKT, the level of MDA and the rate of apoptosis in the penile cavernous tissue were significantly lower, and the levels of p-AKT and p-eNOS, the p-AKT/AKT and p-eNOS/eNOS ratios, and NO and SOD were significantly greater than those in the SHR group (P < .01).

CLINICAL IMPLICATIONS

Icariin may improve the erectile function of hypertension by downregulating GRK2 expression in penile cavernous tissue.

STRENGTHS AND LIMITATIONS

The specific mechanism via which icariin downregulates GRK2 needs to be further elucidated.

CONCLUSION

Icariin downregulates the expression of GRK2 in the penile cavernous tissue of SHRs, upregulates the AKT/eNOS/NO pathway, decreases oxidative stress and apoptosis, and ultimately improves erectile function.

Inhibition of GRK2 reduced doxorubicin-induced oxidative stress and apoptosis through upregulating ADH1

OBJECTIVE

Patients undergoing anti-cancer therapy with doxorubicin (DOX) face the risk of cumulative, irreversible cardiotoxicity. In failing hearts, the overexpressed and activated G protein-coupled receptor kinase 2 (GRK2) initiates pathological signaling, leading to cardiomyocyte death. This study aimed to investigate the potential role of GRK2 in DOX-induced cardiotoxicity (DIC).

METHODS

Mice were administered intraperitoneal injections of DOX (5 mg/kg) weekly for four weeks to induce DIC. Small interfering RNAs (siRNAs) targeting GRK2, ADH1, and PABPC1 were employed in H9c2 cells. Oxidative stress and cell apoptosis were assessed using Reactive Oxygen Species (ROS) staining and TUNEL staining, respectively. Co-immunoprecipitation (Co-IP) was utilized to detect the interaction between GRK2 and PABPC1. RNA immunoprecipitation (RIP) assay was employed to evaluate the binding between PABPC1 and ADH1 mRNA.

RESULTS

GRK2 was found to be upregulated in DOX-treated mouse hearts and H9c2 cells. Cardiomyocyte-specific GRK2 knockout partially mitigated oxidative stress, apoptosis, and cardiac dysfunction. Additionally, GRK2 knockdown attenuated DOX-induced oxidative damage and apoptosis both in vivo and in H9c2 cells. Furthermore, a reduction in ADH1 expression was observed in DOX-treated hearts and cardiomyocytes, with a pronounced increase following GRK2 knockdown. Notably, the beneficial effects of GRK2 knockdown in H9c2 cells were abolished after ADH1 knockdown. Mechanistically, GRK2 knockdown promoted the binding of PABPC1 to ADH1 mRNA, thereby inhibiting the degradation of ADH1 mRNA. Increased ADH1 expression alleviated DOX-induced oxidative stress and apoptosis in cardiomyocytes.

CONCLUSION

In conclusion, our study demonstrates that targeting GRK2 may represent a promising therapeutic strategy for mitigating DOX-associated cardiotoxicity.

Global Research Trends and Focus on the Link Between Heart Failure and NLRP3 Inflammasome: A Bibliometric Analysis From 2010 to 2024

Background

Heart failure (HF) is characterized by elevated morbidity, mortality, and rehospitalization frequencies. This condition imposes a considerable medical burden and fiscal strain on society. Inflammation plays a crucial role in the inception, advancement, and outcome of HF. Despite mounting evidence demonstrating the pivotal function of the NLRP3 inflammasome in HF, a thorough bibliometric examination of research focal points and trajectories in this domain has yet to be undertaken.

Methods

Publications related to the NLRP3 inflammasome in HF were retrieved from the Web of Science database spanning 2010-2024. The acquired data were subsequently analyzed utilizing various visualization instruments, including Citespace, VOSviewer, Scimago Graphica, and Microsoft Office Excel 2021.

Results

A total of 282 papers were included in the analysis, authored by 2,130 researchers from 500 institutions across 34 nations/regions. China emerged as a significant contributor to this field, producing the highest number of outputs. Antonio Abbate was identified as the most prolific author. Virginia Commonwealth University and Wuhan University were the institutions with the highest publication output. INTERNATIONAL IMMUNOPHARMACOLOGY was the periodical with the most numerous publications in this sphere. CIRCULATION, however, received the highest number of citations, indicating its substantial influence on investigations in this field. Contemporary research focal points primarily concentrate on the activation and inhibition pathways of the NLRP3 inflammasome, the exploration of novel HF targets, and the association between HF and mitochondrial function. Future research trajectories are likely to encompass investigations into the relationship between HF and pyroptosis, as well as clinical studies on pharmaceuticals targeting the NLRP3 inflammasome as a therapeutic approach for HF.

Conclusion

This investigation provides a comprehensive bibliometric analysis and synopsis of NLRP3 inflammable-related studies in HF. The findings offer a conceptual foundation for further research on the NLRP3 inflammasome in HF and provide valuable guidance for future research directions in this domain.

Active ingredients of traditional Chinese medicine inhibit NOD-like receptor protein 3 inflammasome: a novel strategy for preventing and treating heart failure

Heart failure (HF) has emerged as a significant global public health challenge owing to its high rates of morbidity and mortality. Activation of the NOD-like receptor protein 3 (NLRP3) inflammasome is regarded as a pivotal factor in the onset and progression of HF. Therefore, inhibiting the activation of the NLRP3 inflammasome may represent a promising therapeutic approach for preventing and treating HF. The active ingredients serve as the foundation for the therapeutic effects of traditional Chinese medicine (TCM). Recent research has revealed significant advantages of TCM active ingredients in inhibiting the activation of the NLRP3 inflammasome and enhancing cardiac structure and function in HF. The study aimed to explore the impact of NLRP3 inflammasome activation on the onset and progression of HF, and to review the current advancements in utilizing TCM active ingredients to inhibit the NLRP3 inflammasome for preventing and treating HF. This provides a novel perspective for the future development of precise intervention strategies targeting the NLRP3 inflammasome to prevent and treat HF.

G protein-coupled receptor kinases in hypertension: physiology, pathogenesis, and therapeutic targets

G protein-coupled receptors (GPCRs) mediate cellular responses to a myriad of hormones and neurotransmitters that play vital roles in the regulation of physiological processes such as blood pressure. In organs such as the artery and kidney, hormones or neurotransmitters, such as angiotensin II (Ang II), dopamine, epinephrine, and norepinephrine exert their functions via their receptors, with the ultimate effect of keeping normal vascular reactivity, normal body sodium, and normal blood pressure. GPCR kinases (GRKs) exert their biological functions, by mediating the regulation of agonist-occupied GPCRs, non-GPCRs, or non-receptor substrates. In particular, increasing number of studies show that aberrant expression and activity of GRKs in the cardiovascular system and kidney inhibit or stimulate GPCRs (e.g., dopamine receptors, Ang II receptors, and α- and β-adrenergic receptors), resulting in hypertension. Current studies focus on the effect of selective GRK inhibitors in cardiovascular diseases, including hypertension. Moreover, genetic studies show that GRK gene variants are associated with essential hypertension, blood pressure response to antihypertensive medicines, and adverse cardiovascular outcomes of antihypertensive treatment. In this review, we present a comprehensive overview of GRK-mediated regulation of blood pressure, role of GRKs in the pathogenesis of hypertension, and highlight potential strategies for the treatment of hypertension. Schematic representation of GPCR desensitization process. Activation of GPCRs begins with the binding of an agonist to its corresponding receptor. Then G proteins activate downstream effectors that are mediated by various signaling pathways. GPCR signaling is halted by GRK-mediated receptor phosphorylation, which causes receptor internalization through β-arrestin.

Omaveloxolone ameliorates isoproterenol-induced pathological cardiac hypertrophy in mice

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important transcriptional regulator that plays a protective role against various cardiovascular diseases. Omaveloxolone is a newly discovered potent activator of Nrf2 that has a variety of cytoprotective functions. However, the potential role of omaveloxolone in the process of pathological cardiac hypertrophy and heart failure are still unknown. In this study, an isoproterenol (ISO)-induced pathological cardiac hypertrophy model was established to investigate the protective effect of omaveloxolone in vivo and in vitro. Our study first confirmed that omaveloxolone administration improved ISO-induced pathological cardiac hypertrophy in mice and neonatal cardiomyocytes. Omaveloxolone administration also diminished ISO-induced cardiac oxidative stress, inflammation and cardiomyocyte apoptosis. In addition, omaveloxolone administration activated the Nrf2 signaling pathway, and Nrf2 knockdown almost completely abolished the cardioprotective effect of omaveloxolone, indicated that the cardioprotective effect of omaveloxolone was directly related to the activation of the Nrf2 signaling. In summary, our study identified that omaveloxolone may be a promising therapeutic agent to mitigate pathological cardiac hypertrophy.