Triptolide improves myocardial fibrosis in rats through inhibition of nuclear factor kappa B and NLR family pyrin domain containing 3 inflammasome pathway

Molecular mechanism of triptolide in myocardial fibrosis through the Wnt/β-catenin signaling pathway

Objective. Myocardial fibrosis (MF) is a common manifestation of end-stage cardiovascular diseases. Triptolide (TP) provides protection against cardiovascular diseases. This study was to explore the functional mechanism of TP in MF rats via the Wnt/β-catenin pathway. Methods. The MF rat model was established via subcutaneous injection of isoproterenol (ISO) and treated with low/medium/high doses of TP (L-TP/M-TP/H-TP) or Wnt agonist BML-284. Cardiac function was examined by echocardiography. Pathological changes of myocardial tissues were observed by HE and Masson staining. Col-I/Col-III/Vimentin/α-SMA levels were detected by immunohistochemistry, RT-qPCR, and Western blot. Collagen volume fraction content was measured. Expression levels of the Wnt/β-catenin pathway-related proteins (β-catenin/c-myc/Cyclin D1) were detected by Western blot. Rat cardiac fibroblasts were utilized for in vitro validation experiments. Results. MF rats had enlarged left ventricle, decreased systolic and diastolic function and cardiac dysfunction, elevated collagen fiber distribution, collagen volume fraction and hydroxyproline content. Levels of Col-I/Col-III/Vimentin/α-SMA, and protein levels of β-catenin/c-myc/Cyclin D1 were increased in MF rats. The Wnt/β-catenin pathway was activated in the myocardial tissues of MF rats. TP treatment alleviated impairments of cardiac function and myocardial tissuepathological injury, decreased collagen fibers, collagen volume fraction, Col-I, Col-III, α-SMA and Vimentin levels, HYP content, inhibited Wnt/β-catenin pathway, with H-TP showing the most significant effects. Wnt agonist BML-284 antagonized the inhibitive effect of TP on MF. TP inhibited the Wnt/β-catenin pathway to repress the proliferation and differentiation of mouse cardiac fibroblasts in vitro. Conclusions. TP was found to ameliorate ISO-induced MF in rats by inhibiting the Wnt/β-catenin pathway.

The role of pyroptosis in heart failure and related traditional chinese medicine treatments

Pyroptosis is a type of programmed cell death that is mediated by both typical and atypical pathways and ultimately leads to the lysis and rupture of cell membranes and the release of proinflammatory factors, triggering an intense inflammatory response. Heart failure (HF) is a serious and terminal stage of various heart diseases. Myocardial hypertrophy, myocardial fibrosis, ventricular remodeling, oxidative stress, the inflammatory response and cardiomyocyte ionic disorders caused by various cardiac diseases are all risk factors for and aggravate HF. Numerous studies have shown that pyroptosis can induce and exacerbate these reactions, causing progression to HF. Therefore, targeting pyroptosis is a promising strategy to treat HF. This paper summarizes the role of pyroptosis in the development of HF and the underlying mechanism involved. Recent research progress on the ability of traditional Chinese medicine (TCM) extracts and formulas to inhibit pyroptosis and treat HF was summarized, and some traditional Chinese medicine extracts and formulas can alleviate different types of HF, including heart failure with preserved ejection fraction (HFpEF), heart failure with reduced ejection fraction (HFrEF), and heart failure with midrange ejection fraction (HFmrEF), by targeting pyroptosis. These findings may provide new ideas and evidence for the treatment or adjuvant treatment of HF by targeting pyroptosis.

Fibroblast-derived interleukin-6 exacerbates adverse cardiac remodeling after myocardial infarction

Myocardial infarction is one of the leading causes of mortality globally. Currently, the pleiotropic inflammatory cytokine interleukin-6 (IL-6) is considered to be intimately related to the severity of myocardial injury during myocardial infarction. Interventions targeting IL-6 are a promising therapeutic option for myocardial infarction, but the underlying molecular mechanisms are not well understood. Here, we report the novel role of IL-6 in regulating adverse cardiac remodeling mediated by fibroblasts in a mouse model of myocardial infarction. It was found that the elevated expression of IL-6 in myocardium and cardiac fibroblasts was observed after myocardial infarction. Further, fibroblast-specific knockdown of Il6 significantly attenuated cardiac fibrosis and adverse cardiac remodeling and preserved cardiac function induced by myocardial infarction. Mechanistically, the role of Il6 contributing to cardiac fibrosis depends on signal transduction and activation of transcription (STAT)3 signaling activation. Additionally, Stat3 binds to the Il11 promoter region and contributes to the increased expression of Il11, which exacerbates cardiac fibrosis. In conclusion, these results suggest a novel role for IL-6 derived from fibroblasts in mediating Stat3 activation and substantially augmented Il11 expression in promoting cardiac fibrosis, highlighting its potential as a therapeutic target for cardiac fibrosis.

Targeting the NLRP3 inflammasome for the treatment of hypertensive target organ damage: Role of natural products and formulations

BACKGROUND AND AIM

Hypertension is a major global health problem that causes target organ damage (TOD) in the heart, brain, kidney, and blood vessels. The mechanisms of hypertensive TOD are not fully understood, and its treatment is challenging. This review provides an overview of the current knowledge on the role of Nod-like receptor pyrin domain containing 3 (NLRP3) inflammasome in hypertensive TOD and the natural products and formulations that inhibit it.

METHODS

We searched PubMed, Web of Science, Google Scholar, and CNKI for relevant articles using the keywords "hypertension," "target organ damage," "NLRP3 inflammasome," "natural products," and "formulations." We reviewed the effects of the NLRP3 inflammasome on hypertensive TOD in different organs and discussed the natural products and formulations that modulate it.

KEY RESULTS

In hypertensive TOD, the NLRP3 inflammasome is activated by various stimuli such as oxidative stress and inflammation. Activation of NLRP3 inflammasome leads to the production of pro-inflammatory cytokines that exacerbate tissue damage and dysfunction. Natural products and formulations, including curcumin, resveratrol, triptolide, and allicin, have shown protective effects against hypertensive TOD by inhibiting the NLRP3 inflammasome.

CONCLUSIONS AND IMPLICATIONS

The NLRP3 inflammasome is a promising therapeutic target in hypertensive TOD. Natural products and formulations that inhibit the NLRP3 inflammasome may provide novel drug candidates or therapies for hypertensive TOD. Further studies are needed to elucidate the molecular mechanisms and optimize the dosages of these natural products and formulations and evaluate their clinical efficacy and safety.

Triptolide protects against podocyte injury in diabetic nephropathy by activating the Nrf2/HO-1 pathway and inhibiting the NLRP3 inflammasome pathway

Objectives: Diabetic nephropathy (DN) is the most common microvascular complication of diabetes mellitus. This study investigated the mechanism of triptolide (TP) in podocyte injury in DN.Methods: DN mouse models were established by feeding with a high-fat diet and injecting with streptozocin and MPC5 podocyte injury models were induced by high-glucose (HG), followed by TP treatment. Fasting blood glucose and renal function indicators, such as 24 h urine albumin (UAlb), serum creatinine (SCr), blood urea nitrogen (BUN), and kidney/body weight ratio of mice were examined. H&E and TUNEL staining were performed for evaluating pathological changes and apoptosis in renal tissue. The podocyte markers, reactive oxygen species (ROS), oxidative stress (OS), serum inflammatory cytokines, nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway-related proteins, and pyroptosis were detected by Western blotting and corresponding kits. MPC5 cell viability and pyroptosis were evaluated by MTT and Hoechst 33342/PI double-fluorescence staining. Nrf2 inhibitor ML385 was used to verify the regulation of TP on Nrf2.Results: TP improved renal function and histopathological injury of DN mice, alleviated podocytes injury, reduced OS and ROS by activating the Nrf2/heme oxygenase-1 (HO-1) pathway, and weakened pyroptosis by inhibiting the nod-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome pathway. In vitro experiments further verified the inhibition of TP on OS and pyroptosis by mediating the Nrf2/HO-1 and NLRP3 inflammasome pathways. Inhibition of Nrf2 reversed the protective effect of TP on MPC5 cells.Conclusions: Overall, TP alleviated podocyte injury in DN by inhibiting OS and pyroptosis via Nrf2/ROS/NLRP3 axis.

A comprehensive review of Tripterygium wilfordii hook. f. in the treatment of rheumatic and autoimmune diseases: Bioactive compounds, mechanisms of action, and future directions

Rheumatic and autoimmune diseases are a group of immune system-related disorders wherein the immune system mistakenly attacks and damages the body's tissues and organs. This excessive immune response leads to inflammation, tissue damage, and functional impairment. Therapeutic approaches typically involve medications that regulate immune responses, reduce inflammation, alleviate symptoms, and target specific damaged organs. Tripterygium wilfordii Hook. f., a traditional Chinese medicinal plant, has been widely studied in recent years for its application in the treatment of autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis. Numerous studies have shown that preparations of Tripterygium wilfordii have anti-inflammatory, immunomodulatory, and immunosuppressive effects, which effectively improve the symptoms and quality of life of patients with autoimmune diseases, whereas the active metabolites of T. wilfordii have been demonstrated to inhibit immune cell activation, regulate the production of inflammatory factors, and modulate the immune system. However, although these effects contribute to reductions in inflammatory responses and the suppression of autoimmune reactions, as well as minimize tissue and organ damage, the underlying mechanisms of action require further investigation. Moreover, despite the efficacy of T. wilfordii in the treatment of autoimmune diseases, its toxicity and side effects, including its potential hepatotoxicity and nephrotoxicity, warrant a thorough assessment. Furthermore, to maximize the therapeutic benefits of this plant in the treatment of autoimmune diseases and enable more patients to utilize these benefits, efforts should be made to strengthen the regulation and standardized use of T. wilfordii.

Friend or foe? The dual role of triptolide in the liver, kidney, and heart

Triptolide, a controversial natural compound due to its significant pharmacological activities and multiorgan toxicity, has gained much attention since it was isolated from the traditional Chinese herb Tripterygium wilfordii Hook F. However, in addition to its severe toxicity, triptolide also presents powerful therapeutic potency in the same organs, such as the liver, kidney, and heart, which corresponds to the Chinese medicine theory of You Gu Wu Yun (anti-fire with fire) and deeply interested us. To determine the possible mechanisms involved in the dual role of triptolide, we reviewed related articles about the application of triptolide in both physiological and pathological conditions. Inflammation and oxidative stress are the two main ways triptolide exerts different roles, and the cross-talk between NF-κB and Nrf2 may be one of the mechanisms responsible for the dual role of triptolide and may represent the scientific connotation of You Gu Wu Yun. For the first time, we present a review of the dual role of triptolide in the same organ and propose the possible scientific connotation of the Chinese medicine theory of You Gu Wu Yun, hoping to promote the safe and efficient use of triptolide and other controversial medicines.

The role of discoid domain receptor 1 on renal tubular epithelial pyroptosis in diabetic nephropathy

Pyroptosis, a form of cell death associated with inflammation, is known to be involved in diabetic nephropathy (DN), and discoid domain receptor 1 (DDR1), an inflammatory regulatory protein, is reported to be associated with diabetes. However, the mechanism underlying DDR1 regulation and pyroptosis in DN remains unknown. We aimed to investigate the effect of DDR1 on renal tubular epithelial cell pyroptosis and the mechanism underlying DN. In this study, we used high glucose (HG)-treated HK-2 cells and rats with a single intraperitoneal injection of streptozotocin as DN models. Subsequently, the expression of pyroptosis-related proteins (cleaved caspase-1, GSDMD-N, Interleukin-1β [IL-1β], and interleukin-18 [IL-18]), DDR1, phosphorylated NF-κB (p-NF-κB), and NLR family pyrin domain-containing 3 (NLRP3) inflammasomes were determined through Western blotting. IL-1β and IL-18 levels were determined using ELISA. The rate of pyroptosis was assessed by propidium iodide (PI) staining. The results revealed upregulated expression of pyroptosis-related proteins and increased concentration of IL-1β and IL-18, accompanied by DDR1, p-NF-κB, and NLRP3 upregulation in DN rat kidney tissues and HG-treated HK-2 cells. Moreover, DDR1 knockdown in the background of HG treatment resulted in inhibited expression of pyroptosis-related proteins and attenuation of IL-1β and IL-18 production and PI-positive cell frequency via the NF-κB/NLRP3 pathway in HK-2 cells. However, NLRP3 overexpression reversed the effect of DDR1 knockdown on pyroptosis. In conclusion, we demonstrated that DDR1 may be associated with pyroptosis, and DDR1 knockdown inhibited HG-induced renal tubular epithelial cell pyroptosis. The NF-κB/NLRP3 pathway is probably involved in the underlying mechanism of these findings.

Therapeutic Implications of Targeting Pyroptosis in Cardiac-related Etiology of Heart Failure

Heart failure remains a considerable clinical and public health problem, it is the dominant cause of death from cardiovascular diseases, besides, cardiovascular diseases are one of the leading causes of death worldwide. The survival of patients with heart failure continues to be low with 45-60% reported deaths within five years. Apoptosis, necrosis, autophagy, and pyroptosis mediate cardiac cell death. Acute cell death is the hallmark pathogenesis of heart failure and other cardiac pathologies. Inhibition of pyroptosis, autophagy, apoptosis, or necrosis reduces cardiac damage and improves cardiac function in cardiovascular diseases. Pyroptosis is a form of inflammatory deliberate cell death that is characterized by the activation of inflammasomes such as NOD-like receptors (NLR), absent in melanoma 2 (AIM2), interferon-inducible protein 16 (IFI-16), and their downstream effector cytokines: Interleukin IL-1β and IL-18 leading to cell death. Recent studies have shown that pyroptosis is also the dominant cell death process in cardiomyocytes, cardiac fibroblasts, endothelial cells, and immune cells. It plays a crucial role in the pathogenesis of cardiac diseases that contribute to heart failure. This review intends to summarize the therapeutic implications targeting pyroptosis in the main cardiac pathologies preceding heart failure.