Casticin elicits inflammasome-induced pyroptosis through activating PKR/JNK/NF-κB signal in 5-8F cells

25-hydroxycholesterol aggravates oxygen-glucose deprivation/reoxygenation-induced pyroptosis through promoting activation of NLRP3 inflammasome in H9C2 cardiomyocytes

25-hydroxycholesterol (25-HC) plays a role in the regulation of cell survival and immunity. However, the effect of 25-HC on myocardial ischemia/reperfusion (MI/R) injury remains unknown. Our present study aimed to investigate whether 25-HC aggravated MI/R injury through NLRP3 inflammasome-mediated pyroptosis. The overlapping differentially expressed genes (DEGs) in MI/R were identified from the GSE775, GSE45818, GSE58486, and GSE46395 datasets in Gene Expression Omnibus (GEO) database. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted using the database of Annotation, Visualization and Integration Discovery (DAVID). The protein-protein interaction (PPI) network of the overlapping DEGs was established using the Search Tool for the Retrieval of Interacting Genes (STRING) database. These bioinformatics analyses indicated that cholesterol 25-hydroxylase (CH25H) was one of the crucial genes in MI/R injury. The oxygen-glucose deprivation/reoxygenation (OGD/R) cell model was established to simulate MI/R injury. Western blot and RT-qPCR analysis demonstrated that CH25H was significantly upregulated in OGD/R-stimulated H9C2 cardiomyocytes. Moreover, knockdown of CH25H inhibited the OGD/R-induced pyroptosis and nod-like receptor protein 3 (NLRP3) inflammasome activation, as demonstrated by cell counting kit-8 (CCK8), lactate dehydrogenase (LDH), RT-qPCR, and western blotting assays. Conversely, 25-HC, which is synthesized by CH25H, promoted activation of NLRP3 inflammasome in OGD/R-stimulated H9C2 cardiomyocytes. In addition, the NLRP3 inhibitor BAY11-7082 attenuated 25-HC-induced H9C2 cell injury and pyroptosis under OGD/R condition. In conclusion, 25-HC could aggravate OGD/R-induced pyroptosis through promoting activation of NLRP3 inflammasome in H9C2 cells.

Pyroptosis in cancer treatment and prevention: the role of natural products and their bioactive compounds

Targeting programmed cell death (PCD) has been emerging as a promising therapeutic strategy in cancer. Pyroptosis, as a type of PCDs, leads to the cleavage of the gasdermin family and the secretion of pro-inflammatory factors. Gasdermin D (GSDMD) and gasdermin E (GSDME) are the two main executors of pyroptosis. Pyroptosis in tumor and immune cells is essential for tumor progression. Natural products, especially Chinese medicinal herb and their bioactive compounds have recently been regarded as anti-tumor agents that regulate cell pyroptosis under different circumstances. Here, we review the underlying mechanisms of natural products that activate pyroptosis in tumor cells and inhibit pyroptosis in immune cells. Pyroptosis activation in tumor cells leads to tumor cell death, yet pyroptosis inhibition in immune cells may prevent tumor occurrence. Elucidation of the signaling pathways involved in pyroptosis contributes to the understanding of the anti-tumor role of natural products and their potential clinical applications. Therefore, we outline a promising strategy for cancer therapy and prevention using natural products via modulation of pyroptosis.

SHP2 potentiates anti-PD-1 effectiveness through intervening cell pyroptosis resistance in triple-negative breast cancer

Triple negative breast cancer (TNBC) presents a formidable challenge due to the lack of effective treatment modalities. Immunotherapy stands as a promising therapeutic approach; however, the emergence of drug resistance mechanisms within tumor cells, particularly those targeting apoptosis and pyroptosis, has hampered its clinical efficacy. SHP2 is intricately involved in diverse physiological processes, including immune cell proliferation, infiltration, and tumor progression. Nevertheless, the precise contribution of SHP2 to tumor cell pyroptosis resistance remains inadequately understood. Herein, we demonstrate that SHP2 inhibition hampers the proliferative, migratory, and invasive capabilities of TNBC, accompanied by noticeable alterations in cellular membrane architecture. Mechanistically, we provide evidence that SHP2 depletion triggers the activation of Caspase-1 and GSDMD, resulting in GSDMD-dependent release of LDH, IL-1β, and IL-18. Furthermore, computational analyses and co-localization investigations substantiate the hypothesis that SHP2 may hinder pyroptosis through direct binding to JNK, thereby impeding JNK phosphorylation. Our cellular experiments further corroborate these findings by demonstrating that JNK inhibition rescues pyroptosis induced by SHP2 knockdown. Strikingly, in vivo experiments validate the suppressive impact of SHP2 knockdown on tumor progression via enhanced JNK phosphorylation. Additionally, SHP2 knockdown augments tumor sensitivity to anti-PD-1 therapy, thus reinforcing the pro-pyroptotic effects and inhibiting tumor growth. In summary, our findings elucidate the mechanism by which SHP2 governs TNBC pyroptosis, underscoring the potential of SHP2 inhibition to suppress cell pyroptosis resistance and its utility as an adjunctive agent for tumor immunotherapy.

Traditional use, phytochemistry and pharmacology of Viticis Fructus

Ethnopharmacological relevance

Viticis Fructus (called Manjingzi in China) is the dried ripe fruits of the plant species Vitex trifolia subsp. litoralis Steenis and Vitex trifolia L. in the family Lamiaceae. Viticis Fructus has been used as a traditional Chinese medicine for thousands of years to treat illness such as colds, headache, vertigo, anesthesia, and hyperkinesias. More chemical constituents and medicinal effects have been discovered in Viticis Fructus with the development of modern technology.The aim of the review: This review aims to analyze the research progress of Viticis Fructus from the aspects of botany, ethnopharmacology, phytochemistry, and pharmacological activity, as well as to provide an outlook on the research and use prospects of Viticis Fructus.

Material and methods

A comprehensive literature search using online databases such Science Direct, CNKI, Wiley online library, Spring Link, Web of Science, PubMed, Wanfang Data and SCI-Finder. In addition, information was obtained from local and foreign books on ethnobotany and ethnomedicine.

Results

The application of Viticis Fructus as a medicine can be traced back to around 480 AD. So far, more than 190 compounds have been isolated from Viticis Fructus, including flavonoids, sterols, cyclic enol ether terpenoids, and diterpenoids. Modern pharmacological studies have shown that the extracts of Viticis Fructus have various pharmacological effects, such as anti-allergic, antioxidant, anti-inflammatory, anti-cancer, and anti-bacterial effects.

Conclusion

As a widely used traditional medicine, Viticis Fructus is rich in chemical compositions and has an obvious biological activity. However, the application and pharmacological activity of Viticis Fructus have not been scientifically evaluated or convincing due to poor methodology, unclear results and lack of clinical data. Systematic and comprehensive research evaluations are needed to verify its pharmaceutical activity, clinical therapeutic efficacy and safety. As an important herbal medicine, it should be further explored to facilitate the development of new medicines and treatments for a variety of diseases.

Unveiling the therapeutic potential of natural-based anticancer compounds inducing non-canonical cell death mechanisms

In the Mid-19th century, Rudolf Virchow considered necrosis to be a prominent form of cell death; since then, pathologists have recognized necrosis as both a cause and a consequence of disease. About a century later, the mechanism of apoptosis, another form of cell death, was discovered, and we now know that this process is regulated by several molecular mechanisms that "programme" the cell to die. However, discoveries on cell death mechanisms are not limited to these, and recent studies have allowed the identification of novel cell death pathways that can be molecularly distinguished from necrotic and apoptotic cell death mechanisms. Moreover, the main goal of current cancer therapy is to discover and develop drugs that target apoptosis. However, resistance to chemotherapeutic agents targeting apoptosis is mainly responsible for the failure of clinical therapy and adverse side effects of the chemotherapeutic agents currently in use pose a major threat to the well-being and lives of patients. Therefore, the development of natural-based anticancer drugs with low cellular and organismal side effects is of great interest. In this comprehensive review, we thoroughly examine and discuss natural anticancer compounds that specifically target non-canonical cell death mechanisms.

Progress in the study of molecular mechanisms of cell pyroptosis in tumor therapy

Pyroptosis, also known as cellular inflammatory necrosis, is a programmed cell death mediated by the Gasdermin family of proteins. The mechanisms by which pyroptosis occurs are divided into the GSDMD-mediated Caspase-1 and Caspase-4/-5/-11-dependent classical inflammatory vesicle pathway and the GSDME-mediated Caspase-3 and granzyme-dependent non-classical inflammatory vesicle pathways, among others. Recent studies have shown that pyroptosis has both inhibitory and promotive effects on tumor development. Pyroptosis induction also plays a dual role in antitumor immunotherapy: on the one hand, it suppresses antitumor immunity by promoting the release of inflammatory factors, and on the other hand, it inhibits tumor cell proliferation by triggering antitumor inflammatory responses. In addition, cell scorching plays an essential role in chemotherapy. It has been found that natural drugs modulating the induction of cell scorch are necessary to treat tumors. Therefore, studying the specific mechanisms of cell pyroptosis in different tumors can provide more ideas for developing oncology drugs. In this paper, we review the molecular mechanisms of pyroptosis and the role of pyroptosis in tumor development and treatment to provide new targets for clinical tumor treatment, prognosis, and antitumor drug development.

Saturated Fatty Acid-Induced Endoplasmic Reticulum Stress and Insulin Resistance Are Prevented by Imoxin in C2C12 Myotubes

In obesity, plasma free fatty acids (FFAs) levels are elevated due to enlarged adipose tissue mass. Saturated fatty acids can induce prolonged ER stress and insulin resistance. Double-stranded RNA-dependent Protein Kinase (PKR) is activated under stress conditions in skeletal muscle. The current study aimed to investigate the effect of imoxin (IMX), a selective PKR inhibitor, on palmitate-induced ER stress and insulin resistance in C2C12 myotubes. Cells were treated with 5 μM imoxin and exposed to 0.5 mM bovine serum albumin (BSA)-conjugated PA for 24 h. A subset of cells was stimulated with 50 nM insulin for the last 15 min. Glucose uptake was monitored and protein levels involved in ER stress and insulin signaling were measured by Western blotting. Palmitate stimulated PKR phosphorylation, which was prevented by imoxin. Moreover, imoxin reduced protein levels of ER stress-related markers including glucose-regulating protein 78 (GRP78), CCAAT-enhancer-binding protein homologous protein (CHOP), activating transcription factor 6 (ATF6) and spliced X-box binding protein 1 (XBP-1s) which were induced by palmitate. Furthermore, imoxin ameliorated palmitate-induced suppression of phospho-insulin receptor beta (p-IRβ) and Akt phosphorylation in myotubes. In addition, imoxin promoted glucose uptake in response to insulin under palmitate exposure. Furthermore, imoxin reduced phospho-c-Jun N-terminal kinase (p-JNK) induced by palmitate treatment. These findings suggest that imoxin may protect against saturated fatty acid-induced ER stress and insulin resistance in skeletal muscle, which are potentially mediated by PKR.

LncRNA ROR modulates myocardial ischemia-reperfusion injury mediated by the miR-185-5p/CDK6 axis

LncRNAs and miRNAs are correlated with the pathogenesis of myocardial ischemia-reperfusion injury (MIRI). Whether lncRNA ROR or miR-185-5p plays a crucial role in MIRI is still unclear. In in-vitro, human cardiac myocytes (HCMs) were treated with hypoxia/reoxygenation (H/R). Wistar rats were used to set up an in-vitro I/R model by means of recanalization after ligation. Evaluation of the myocardial injury marker lactate dehydrogenase (LDH) in HCMs cells was performed. The expression of miR-185-5p and ROR, IL-1β, and IL-18 were detected by qRT-PCR. ELISA was also performed to evaluate the secretion of IL-1β and IL-18. Western blotting was carried out to determine CDK6, NLRP3, GSDMD-N, ASC, and cleaved-caspase1 protein expression. The relationship between miR-185-5p and CDK6 or ROR was confirmed by a dual-luciferase reporter assay. Our findings revealed that H/R treated HCMs showed a significantly decreased miR-185-5p expression and increased expression of CDK6 and ROR. ROR knockdown reduced H/R induced pyroptosis and inflammation, while knockdown of miR-185-5p accelerated the effect. Furthermore, miR-185-5p was negatively regulated and absorbed by ROR in HCMs. Overexpression of miR-185-5p reversed the H/R-induced cell pyroptosis and upregulation of LDH, IL-1β, and IL-18. In HCMs, miR-185-5p was also negatively regulated and related to CDK6 expression. Moreover, overexpression of CDK6 significantly inhibited the effects of miR-185-5p mimics on the inflammatory response and pyroptosis of HCMs. Knockdown of ROR alleviated H/R-induced myocardial injury by elevating miR-185-5p and inhibiting CDK6 expression. Taken together, our results show that the ROR/miR-185-5p/CDK6 axis modulates cell pyroptosis induced by H/R and the inflammatory response of HCMs.

Metadherin silencing results in the inhibition of pyroptosis in lipopolysaccharide/adenosine triphosphate - stimulated renal tubular epithelial cells

Pyroptosis is induced following inflammation via activation of the NLRP3 inflammasome. Lipopolysaccharide (LPS)-induced acute inflammation causes pyroptosis in renal tubular epithelial cells, which aggravates kidney damage and is involved in physiopathological processes in multiple renal diseases. Metadherin (Mtdh) induces inflammation by NLRP3 inflammasome activation. Specifically, it induces inflammatory injury in the kidney by activating the nuclear factor kappa B (NF-κB) signaling pathway, which is involved in NLRP3 inflammasome activation. However, the role of Mtdh in pyroptosis in renal tubular epithelial cells is unclear. Therefore, we investigated whether Mtdh participates in pyroptosis in LPS/adenosine triphosphate (ATP)-treated NRK-52E cells by activating the NLRP3 inflammasome and NF-κB signaling pathway. We induced pyroptosis in NRK-52E cells with LPS/ATP, after which Mtdh was silenced via transfection with small interfering RNA. LPS/ATP upregulated Mtdh expression and induced pyroptosis and NLRP3 inflammasome activation in NRK-52E cells. However, downregulation of Mtdh expression resulted in the alleviation of pyroptosis in LPS/ATP-treated NRK-52E cells. Additionally, activation of the NLRP3 inflammasome and NF-κB signaling pathway was inhibited. This demonstrates that downregulation of Mtdh expression results in the inhibition of pyroptosis in LPS/ATP-treated NRK-52E cells through the suppression of NLRP3 inflammasome activation, which occurs via inhibition of the NF-κB signaling pathway.

Do pyroptosis, apoptosis, and necroptosis (PANoptosis) exist in cerebral ischemia? Evidence from cell and rodent studies

Some scholars have recently developed the concept of PANoptosis in the study of infectious diseases where pyroptosis, apoptosis and necroptosis act in consort in a multimeric protein complex, PANoptosome. This allows all the components of PANoptosis to be regulated simultaneously. PANoptosis provides a new way to study the regulation of cell death, in that different types of cell death may be regulated at the same time. To test whether PANoptosis exists in diseases other than infectious diseases, we chose cerebral ischemia/reperfusion injury as the research model, collected articles researching cerebral ischemia/reperfusion from three major databases, obtained the original research data from these articles by bibliometrics, data mining and other methods, then integrated and analyzed these data. We selected papers that investigated at least two of the components of PANoptosis to check its occurrence in ischemia/reperfusion. In the cell model simulating ischemic brain injury, pyroptosis, apoptosis and necroptosis occur together and this phenomenon exists widely in different passage cell lines or primary neurons. Pyroptosis, apoptosis and necroptosis also occurred in rat and mouse models of ischemia/reperfusion injury. This confirms that PANoptosis is observed in ischemic brain injury and indicates that PANoptosis can be a target in the regulation of various central nervous system diseases.

Pyroptosis in stroke-new insights into disease mechanisms and therapeutic strategies

Stroke is a common disease with high mortality and disability worldwide. Different forms of cell deaths, including apoptosis and necrosis, occur in ischemic or hemorrhagic brain tissue, among which pyroptosis, a newly discovered inflammation-related programmed cell death, is generally divided into two main pathways, the canonical inflammasome pathway and the non-canonical inflammasome pathway. Caspase-mediated pyroptosis requires the assembly of inflammasomes such as NLRP3, which leads to the release of inflammatory cytokines IL-1β and IL-18 through the pores formed in the plasma membrane by GSDMD followed by neuroinflammation. Recently, pyroptosis and its relationship with inflammation have attracted more and more attention in the study of cerebral ischemia or hemorrhage. In addition, many inhibitors of pyroptosis targeting caspase, NLRP3, and the upstream pathway have been found to reduce brain tissue damage after stroke. In this review, we mainly introduce the pathology of stroke, the molecular mechanism, and process of pyroptosis, as well as the pivotal roles of pyroptosis in stroke, in order to provide new insights for the treatment of stroke.

Casticin protected against neuronal injury and inhibited the TLR4/NF-κB pathway after middle cerebral artery occlusion in rats

Although stroke is a major human neurological disease, there is a paucity of effective neuroprotectants that can improve its treatment. Casticin is a natural monomer drug with many biological effects such as anti-inflammatory and anti-tumor actions. However, it is not clear whether it has a neuroprotective effect in ischemic stroke. In this study, the neuroprotective effect of casticin in a rat middle cerebral artery occlusion (MCAO) model was investigated. Results showed that casticin reduced the volume of the cerebral infarction, mNSS scores, swimming distance, time to find the submerged platform, and serum concentrations of TNF-α, TGF-β, IL-6 in MCAO rats. Moreover, casticin also decreased the expression of TLR4, NF-κB p65, and NF-κB p50 proteins and reversed the reduced expression of IκB protein in the brain tissue of MCAO rats. The in vitro study revealed that casticin decreased apoptosis of OGD/R-PC12 cells, reduced the expression of TLR4, NF-κB p65, and NF-κB p50, while increased IκB protein expression. In conclusion, casticin improved the neurological functions of MCAO rats via inhibiting the TLR4/NF-κB pathway and might have the potential to be developed into a neuroprotective agent for stroke patients.

Induction of Pyroptosis: A Promising Strategy for Cancer Treatment

Pyroptosis, a lytic pro-inflammatory type of programmed cell death, has been widely studied in diverse inflammatory disease models. Membrane perforation and cell swelling induced by cleaved gasdermin family members is the main characteristic of pyroptosis. Emerging evidence has revealed a complicated relationship between pyroptosis and cancer. On the one hand, as inflammatory cell death, pyroptosis provides a comfortable environment for tumor proliferation. On the other hand, excessive activation of pyroptosis can inhibit the development of tumor cells. In this review, we first summarized the latest progress about the molecular mechanism of pyroptosis. Then, members from gasdermin family, the central molecules of pyroptosis which formed pores on the cell membrane, were highlighted. In the second part of this review, we summarized drugs that induced pyroptosis in different tumors and their concrete mechanisms based on recent literature reports. In the final section, we discussed several hotspots in pyroptosis and cancer therapy, which will point out the direction of sequent research. In brief, inducing pyroptosis in cancer cells is a promising strategy for cancer therapy.

Natural Products as Inducers of Non-Canonical Cell Death: A Weapon against Cancer

Simple Summary

Anticancer therapeutic approaches based solely on apoptosis induction are often unsuccessful due to the activation of resistance mechanisms. The identification and characterization of compounds capable of triggering non-apoptotic, also called non-canonical cell death pathways, could represent an important strategy that may integrate or offer alternative approaches to the current anticancer therapies. In this review, we critically discuss the promotion of ferroptosis, necroptosis, and pyroptosis by natural compounds as a new anticancer strategy.

Abstract

Apoptosis has been considered the main mechanism induced by cancer chemotherapeutic drugs for a long time. This paradigm is currently evolving and changing, as increasing evidence pointed out that antitumor agents could trigger various non-canonical or non-apoptotic cell death types. A considerable number of antitumor drugs derive from natural sources, both in their naturally occurring form or as synthetic derivatives. Therefore, it is not surprising that several natural compounds have been explored for their ability to induce non-canonical cell death. The aim of this review is to highlight the potential antitumor effects of natural products as ferroptosis, necroptosis, or pyroptosis inducers. Natural products have proven to be promising non-canonical cell death inducers, capable of overcoming cancer cells resistance to apoptosis. However, as discussed in this review, they often lack a full characterization of their antitumor activity together with an in-depth investigation of their toxicological profile.

Periostin aggravates NLRP3 inflammasome-mediated pyroptosis in myocardial ischemia-reperfusion injury

Pyroptosis is a form of caspase-1-induced programmed cell death. This study aimed to investigate the effect of periostin (postn) on pyroptosis in myocardial ischemia-reperfusion injury (MIRI). To this end, the differentially expressed genes were obtained from the GSE4105 dataset using the "GEO2R" online tool. Protein-protein interaction networks were constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) database, and Module and Go analysis were conducted using the Cytoscape 3.6 plugs-in MCODE and BINGO, respectively. The analysis showed that postn was a critical gene in the most significant module. Experimental results, including triphenyltetrazolium chloride staining, pathological analysis, TUNEL staining, western blotting, and RT-qPCR assays, showed that MIRI induced caspase-1-mediated pyroptosis by activating the NLRP3 inflammasome. Postn was significantly upregulated in the heart tissues of MIRI rats and in H9C2 cells following hypoxia/reoxygenation (H/R) treatment. In addition, knockdown of postn suppressed the caspase-1-mediated pyroptosis and H/R-mediated NLRP3 inflammasome activation, as evidenced by flow cytometry, CCK8, RT-qPCR, western blotting, and ELISA assays. In contrast, overexpression of postn promoted NLRP3 inflammasome-mediated pyroptosis of H/R-treated H9C2 cells. According to the results of rescue experiments, a caspase-1 inhibitor reduced the increase in NLRP3 inflammasome-mediated pyroptosis induced by overexpression of postn, and the pyroptosis-promoting function of postn overexpression in H/R treated H9C2 cells was reversed by inhibition of NLRP3. In conclusion, postn overexpression promoted the caspase-1-mediated pyroptosis during MIRI by activating the NLRP3.