Micheliolide Attenuates Lipopolysaccharide-Induced Inflammation by Modulating the mROS/NF-κB/NLRP3 Axis in Renal Tubular Epithelial Cells

Micheliolide ameliorates lipopolysaccharide-induced acute kidney injury through suppression of NLRP3 activation by promoting mitophagy via Nrf2/PINK1/Parkin axis

BACKGROUND

Sepsis-associated acute kidney injury (SA-AKI) represents a frequent complication of in critically ill patients. The objective of this study is to illuminate the potential protective activity of Micheliolide (MCL) and its behind mechanism against SA-AKI.

METHODS

The protective potential of MCL on SA-AKI was investigated in lipopolysaccharide (LPS) treated HK2 cells and SA-AKI mice model. The mitochondrial damage was determined by detection of reactive oxygen species and membrane potential. The Nrf2 silencing was achieved by transfection of Nrf2-shRNA in HK2 cells, and Nrf2 inhibitor, ML385 was employed in SA-AKI mice. The mechanism of MCL against SA-AKI was evaluated through detecting hallmarks related to inflammation, mitophagy and Nrf2 pathway via western blotting, immunohistochemistry, and enzyme linked immunosorbent assay.

RESULTS

MCL enhanced viability, suppressed apoptosis, decreased inflammatory cytokine levels and improved mitochondrial damage in LPS-treated HK2 cells, and ameliorated renal injury in SA-AKI mice. Moreover, MCL could reduce the activation of NLRP3 inflammasome via enhancing mitophagy. Additionally, Nrf2 deficiency reduced the suppression effect of MCL on NLRP3 inflammasome activation and blocked the facilitation effect of MCL on mitophagy in LPS-treated HK2 cells, the consistent is true for ML385 treatment in SA-AKI mice.

CONCLUSIONS

MCL might target Nrf2 and further reduce the NLRP3 inflammasome activation via enhancing mitophagy, which alleviated SA-AKI.

Crosstalk between Dysfunctional Mitochondria and Proinflammatory Responses during Viral Infections

Mitochondria play pivotal roles in sustaining various biological functions including energy metabolism, cellular signaling transduction, and innate immune responses. Viruses exploit cellular metabolic synthesis to facilitate viral replication, potentially disrupting mitochondrial functions and subsequently eliciting a cascade of proinflammatory responses in host cells. Additionally, the disruption of mitochondrial membranes is involved in immune regulation. During viral infections, mitochondria orchestrate innate immune responses through the generation of reactive oxygen species (ROS) and the release of mitochondrial DNA, which serves as an effective defense mechanism against virus invasion. The targeting of mitochondrial damage may represent a novel approach to antiviral intervention. This review summarizes the regulatory mechanism underlying proinflammatory response induced by mitochondrial damage during viral infections, providing new insights for antiviral strategies.

ZBP1 promotes hepatocyte pyroptosis in acute liver injury by regulating the PGAM5/ROS pathway

INTRODUCTION AND OBJECTIVES

Acute liver injury (ALI) is characterized by massive hepatocyte death with high mortality and poor prognosis. Hepatocyte pyroptosis plays a key role in the physiopathological processes of ALI, which can damage mitochondria and release NLRP3 inflammasome particles, causing systemic inflammatory responses. Z-DNA Binding Protein 1 (ZBP1) is a sensor that induces cell death. Here, we investigated whether ZBP1 participates in hepatocyte pyroptosis and explored the possible pathogenesis of ALI.

MATERIALS AND METHODS

Hepatocyte pyrotosis was induced with lipopolysaccharide (LPS) and nigericin (Nig), and the expression of Zbp1 (ZBP1) was examined by western blot analysis and RT-qPCR. Further, we transfected AML-12 (LO2 and HepG2) cell lines with Zbp1 (ZBP1) siRNA. After ZBP1 was silenced, LDH release and flow cytometry were used to measure the cell death; Western blot analysis and RT-qPCR were used to detect the marker of NLRP3 inflammasome activation and pyroptosis. We also detected the expression of mitochondrial linear rupture marker phosphoglycerate mutase family member 5 (PGAM5) using western blot analysis and reactive oxygen species (ROS) using the DCFH-DA method.

RESULTS

The expression of ZBP1 was up-regulated in LPS/Nig-induced hepatocytes. Si-Zbp1 (Si-ZBP1) inhibited NLRP3 inflammasome activation and pyroptosis in LPS/Nig-induced hepatocytes. Moreover, ZBP1 silencing inhibited the expression of PGAM5 by reducing ROS production.

CONCLUSIONS

ZBP1 promotes hepatocellular pyroptosis by modulating mitochondrial damage, which facilitates the extracellular release of ROS.

The combined effects of polystyrene nanoplastics with nickel on oxidative stress and related toxic effects to earthworms from individual and cellular perspectives

Nanoplastics may adsorb other pollutants in the environment due to their high specific surface area and small size. We used earthworms as experimental organisms to evaluate the ecotoxicity of NPs and Ni combined pollution at the individual and cellular levels. The results showed that when only 20 mg/L Ni2+ was added to the combined pollution system, the antioxidant system of earthworm coelomocytes was destroyed to a certain extent, the ROS level increased, the cell viability decreased significantly, and the redox balance was destroyed. With the introduction of PS-NPs and the increase of concentration, the oxidative damage in the coelomocytes of earthworms gradually increased, and finally tended to be stable when the maximum concentration of 50 mg/L PS-NPs and Ni were exposed together. At the animal level, the activities of CAT and SOD decreased within 28 days of exposure, and the combined pollution showed a synergistic effect. At the same time, it promoted the synthesis of GST in earthworms, improved their detoxification ability and reduced oxidative damage. The changes of T-AOC and MDA showed that the combined pollution caused the accumulation of ROS and caused more serious toxicological effects. With the increase of exposure time, the antioxidant system of earthworms was continuously destroyed, and the oxidative damage was serious, which induced more serious lipid peroxidation and caused the damage of earthworm body wall structure.

Potential therapeutic medicines for renal fibrosis: Small-molecule compounds and natural products

Renal fibrosis is the pathological change process of chronic kidney disease deteriorating continuously. When the renal organ is stimulated by external stimuli, it will trigger the damage and phenotypic changes of some intrinsic cells in the kidney. When the body's autoimmune regulation or external treatment is not prompted enough to restore the organ, the pathological process is gradually aggravating, inducing a large amount of intracellular collagen deposition, which leads to the appearance of fibrosis and scarring. The renal parenchyma (including glomeruli and tubules) begins to harden, making it difficult to repair the kidney lesions. In the process of gradual changes in the kidney tissue, the kidney units are severely damaged and the kidney function shows a progressive decline, eventually resulting in the clinical manifestation of end-stage renal failure, namely uremia. This review provides a brief description of the diagnosis, pathogenesis, and potential therapeutic inhibitors of renal fibrosis. Since renal fibrosis has not yet had a clear therapeutic target and related drugs, some potential targets and relevant inhibitors are discussed, especially pharmacological effects and interactions with targets. Some existing natural products have potential efficacy for renal fibrosis, which is also roughly summarized, hoping that this article would have reference significance for the treatment of renal fibrosis.

MCL attenuates atherosclerosis by suppressing macrophage ferroptosis via targeting KEAP1/NRF2 interaction

BACKGROUND

Micheliolide (MCL), which is the active metabolite of parthenolide, has demonstrated promising clinical application potential. However, the effects and underlying mechanisms of MCL on atherosclerosis are still unclear.

METHOD

ApoE-/- mice were fed with high fat diet, with or without MCL oral administration, then the plaque area, lipid deposition and collagen content were determined. In vitro, MCL was used to pretreat macrophages combined by ox-LDL, the levels of ferroptosis related proteins, NRF2 activation, mitochondrial function and oxidative stress were detected.

RESULTS

MCL administration significantly attenuated atherosclerotic plaque progress, which characteristics with decreased plaque area, less lipid deposition and increased collagen. Compared with HD group, the level of GPX4 and xCT in atherosclerotic root macrophages were increased in MCL group obviously. In vitro experiment demonstrated that MCL increased GPX4 and xCT level, improved mitochondrial function, attenuated oxidative stress and inhibited lipid peroxidation to suppress macrophage ferroptosis induced with ox-LDL. Moreover, MCL inhibited KEAP1/NRF2 complex formation and enhanced NRF2 nucleus translocation, while the protective effect of MCL on macrophage ferroptosis was abolished by NRF2 inhibition. Additionally, molecular docking suggests that MCL may bind to the Arg483 site of KEAP1, which also contributes to KEAP1/NRF2 binding. Furthermore, Transfection Arg483 (KEAP1-R483S) mutant plasmid can abrogate the anti-ferroptosis and anti-oxidative effects of MC in macrophages. KEAP1-R483S mutation also limited the protective effect of MCL on atherosclerosis progress and macrophage ferroptosis in ApoE-/- mice.

CONCLUSION

MCL suppressed atherosclerosis by inhibiting macrophage ferroptosis via activating NRF2 pathway, the related mechanism is through binding to the Arg483 site of KEAP1 competitively.

Micheliolide exerts effects in myeloproliferative neoplasms through inhibiting STAT3/5 phosphorylation via covalent binding to STAT3/5 proteins

Ruxolitinib is a cornerstone of management for some subsets of myeloproliferative neoplasms (MPNs); however, a considerable number of patients respond suboptimally. Here, we evaluated the efficacy of micheliolide (MCL), a natural guaianolide sesquiterpene lactone, alone or in combination with ruxolitinib in samples from patients with MPNs, JAK2V617F-mutated MPN cell lines, and a Jak2V617F knock-in mouse model. MCL effectively suppressed colony formation of hematopoietic progenitors in samples from patients with MPNs and inhibited cell growth and survival of MPN cell lines in vitro. Co-treatment with MCL and ruxolitinib resulted in greater inhibitory effects compared with treatment with ruxolitinib alone. Moreover, dimethylaminomicheliolide (DMAMCL), an orally available derivative of MCL, significantly increased the efficacy of ruxolitinib in reducing splenomegaly and cytokine production in Jak2V617F knock-in mice without evident effects on normal hematopoiesis. Importantly, MCL could target the Jak2V617F clone and reduce mutant allele burden in vivo. Mechanistically, MCL can form a stable covalent bond with cysteine residues of STAT3/5 to suppress their phosphorylation, thus inhibiting JAK/STAT signaling. Overall, these findings suggest that MCL is a promising drug in combination with ruxolitinib in the setting of suboptimal response to ruxolitinib.

Brahma-related gene 1 acts as a profibrotic mediator and targeting it by micheliolide ameliorates peritoneal fibrosis

BACKGROUND

Progressive peritoneal fibrosis is a worldwide public health concern impacting patients undergoing peritoneal dialysis (PD), yet there is no effective treatment. Our previous study revealed that a novel compound, micheliolide (MCL) inhibited peritoneal fibrosis in mice. However, its mechanism remains unclear. Brahma-related gene 1 (BRG1) is a key contributor to organ fibrosis, but its potential function in PD-related peritoneal fibrosis and the relationship between MCL and BRG1 remain unknown.

METHODS

The effects of MCL on BRG1-induced fibrotic responses and TGF-β1-Smads pathway were examined in a mouse PD model and in vitro peritoneal mesothelial cells. To investigate the targeting mechanism of MCL on BRG1, coimmunoprecipitation, MCL-biotin pulldown, molecular docking and cellular thermal shift assay were performed.

RESULTS

BRG1 was markedly elevated in a mouse PD model and in peritoneal mesothelial cells cultured in TGF-β1 or PD fluid condition. BRG1 overexpression in vitro augmented fibrotic responses and promoted TGF-β1-increased-phosphorylation of Smad2 and Smad3. Meanwhile, knockdown of BRG1 diminished TGF-β1-induced fibrotic responses and blocked TGF-β1-Smad2/3 pathway. MCL ameliorated BRG1 overexpression-induced peritoneal fibrosis and impeded TGF-β1-Smad2/3 signaling pathway both in a mouse PD model and in vitro. Mechanically, MCL impeded BRG1 from recognizing and attaching to histone H3 lysine 14 acetylation by binding to the asparagine (N1540) of BRG1, in thus restraining fibrotic responses and TGF-β1-Smad2/3 signaling pathway. After the mutation of N1540 to alanine (N1540A), MCL was unable to bind to BRG1 and thus, unsuccessful in suppressing BRG1-induced fibrotic responses and TGF-β1-Smad2/3 signaling pathway.

CONCLUSION

Our research indicates that BRG1 may be a crucial mediator in peritoneal fibrosis and MCL targeting N1540 residue of BRG1 may be a novel therapeutic strategy to combat PD-related peritoneal fibrosis.

Exosomes: A novel insight into traditional Chinese medicine

Exosomes are small extracellular vesicles and play an essential role in the mediation of intercellular communication both in health and disease. Traditional Chinese medicine (TCM) has historically been used to maintain human health and treat various diseases up till today. The interplay between exosomes and TCM has attracted researchers’ growing attention. By integrating the available evidence, TCM formulas and compounds isolated from TCM as exosome modulators have beneficial effects on multiple disorders, such as tumors, kidney diseases, and hepatic disease, which may associate with inhibiting cells proliferation, anti-inflammation, anti-oxidation, and attenuating fibrosis. Exosomes, a natural delivery system, are essential in delivering compounds isolated from TCM to target cells or tissues. Moreover, exosomes may be the potential biomarkers for TCM syndromes, providing strategies for TCM treatment. These findings may provide a novel insight into TCM from exosomes and serve as evidence for better understanding and development of TCM.

Cancer metabolism control by natural products: Pyruvate kinase M2 targeting therapeutics

Glycolysis is the primary source of energy for cancer growth and metastasis. The shift in metabolism from mitochondrial oxidative phosphorylation to aerobic glycolysis is called the Warburg effect. Cancer progression due to aerobic glycolysis is often associated with the activation of oncogenes or the loss of tumor suppressors. Therefore, inhibition of glycolysis is one of the effective strategies in cancer control. Pyruvate kinase M2 (PKM2) is a key glycolytic enzyme overexpressed in breast, prostate, lung, colorectal, and liver cancers. Here, we discuss published studies regarding PKM2 inhibitors from natural products that are promising drug candidates for cancer therapy. We have highlighted the potential of natural PKM2 inhibitors for various cancer types. Moreover, we encourage researchers to evaluate the combinational effects between natural and synthetic PKM2 inhibitors. Also, further high-quality studies are needed to firmly establish the clinical efficacy of natural products.

ACT001 suppressing M1 polarization against inflammation via NF-κB and STAT1 signaling pathways alleviates acute lung injury in mice

ACT001 has been shown to exhibit excellent antitumor and anti-fibrosis activities. However, the role of ACT001 in acute lung injury (ALI) and the underlying mechanism remains largely unclear. The present study aimed to investigate the protective effects of ACT001 on ALI and explore the potential mechanisms. Herein, we firstly established the ALI mouse model induced by intratracheal instillation of lipopolysaccharide (LPS). ACT001 treatment significantly alleviated histopathological changes of lung tissues with lower infiltration of pulmonary M1 macrophages in ALI mice. Then, we performed in vitro experiment and found that ACT001 treatment effectively inhibited the M1 phenotype of RAW264.7 and THP-1.. Next, we performed pull-down and mass spectrometry analysis to screen the interacting proteins of ACT001, identifying IKKβ and STAT1 as the critical target proteins of ACT001. And ACT001 treatment significantly suppressed the NF-κB and STAT1 pathways, thereby inhibiting the M1 polarization against inflammation in vivo and in vitro. Finally, we used IMD 0354 (IMD) and Fludarabine (Flud) to specifically block the activity of IKKβ and STAT1, and stimulated macrophages through IKKβ and STAT1 overexpression. Our data clearly showed that ACT001-induced decrease of the M1 polarization was blocked by IMD and Flud treatment, and reversed by IKKβ and STAT1 overexpression in RAW264.7 cells. In conclusion, we discovered that ACT001 significantly alleviates inflammation and limits M1 phenotype of pulmonary macrophages via suppressing NF-κB and STAT1 signaling pathways, providing new insights for the development of drugs to treat ALI/ARDS.

Paeoniflorin ameliorates lipopolysaccharide-induced acute liver injury by inhibiting oxidative stress and inflammation via SIRT1/FOXO1a/SOD2 signaling in rats

Acute liver injury (ALI) is a poor prognosis and high mortality complication of sepsis. Paeoniflorin (PF) has remarkable anti-inflammatory effects in different disease models. Here, we explored the protective effect and underlying molecular mechanisms of PF against lipopolysaccharide (LPS)-induced ALI. Sprague-Dawley rats received intraperitoneal (i.p.) injection of PF for 7 days, 1 h after the last administration, and rats were injected i.p. 10 mg/kg LPS. PF improved liver structure and function, reduced hepatic reactive oxygen species (ROS) and methane dicarboxylic aldehyde (MDA) levels, and increased superoxide dismutase (SOD) activity. Western blot analysis suggested that PF significantly inhibited expression of inflammatory cytokines (TNF-α, IL-1β, and IL-18) and inhibited activation of the NLRP3 inflammasome. PF or mitochondrial ROS scavenger (mito-TEMPO) significantly improved liver mitochondrial function by scavenging mitochondrial ROS (mROS), restoring mitochondrial membrane potential loss and increasing level of ATP and enzyme activity of complex I and III. In addition, PF increased expression of sirtuin-1 (SIRT1), forkhead box O1 (FOXO1a) and manganese superoxide dismutase (SOD2), and increased FOXO1a nuclear retention. However, the inhibitor of SIRT1 (EX527) abolished the protective effect of PF. Taken together, PF promotes mROS clearance to inhibit mitochondrial damage and activation of the NLRP3 inflammasome via SIRT1/FOXO1a/SOD2 signaling.

Suppression of NLRP3 inflammasome by Platycodin D via the TLR4/MyD88/NF-κB pathway contributes to attenuation of lipopolysaccharide induced acute lung injury in rats

Acute lung injury (ALI) is a common clinical condition with a high mortality rate and no specific treatment is available. An excessive inflammatory response contributes to the development of ALI and accelerates its progression, and the NLRP3 inflammasome and NF-κB signaling pathways are key players in inflammation. Platycodin D has been reported to have anti-oxidant and anti-stress properties in various diseases. However, the effects of PLD in ALI has not been clearly demonstrated. The aim of this study was to investigate the therapeutic effects of PLD on ALI and its possible mechanism. Our study found that PLD pre-treatment attenuated lung histopathological injury in LPS-induced SD rats and reduced the levels of inflammatory cytokines and lung wet/dry ratio in bronchoalveolar lavage fluid (BALF). In addition, PLD modulate LPS-induced production of MDA, MPO, GSH, GSH-Px and CAT in lung tissue. In addition, PLD suppressed the activation of NLRP3 inflammatory microsomes and the NF-κB signaling pathway. Thus, our results suggest that PLD are protective against LPS-induced ALI by inhibiting NLRP3 and NF-κB signaling pathway.

Protective Effect of Mitochondria-Targeted Antioxidants against Inflammatory Response to Lipopolysaccharide Challenge: A Review

Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, is the most abundant proinflammatory agent. Considerable evidence indicates that LPS challenge inescapably causes oxidative stress and mitochondrial dysfunction, leading to cell and tissue damage. Increased mitochondrial reactive oxygen species (mtROS) generation triggered by LPS is known to play a key role in the progression of the inflammatory response. mtROS at excessive levels impair electron transport chain functioning, reduce the mitochondrial membrane potential, and initiate lipid peroxidation and oxidative damage of mitochondrial proteins and mtDNA. Over the past 20 years, a large number of mitochondria-targeted antioxidants (mito-AOX) of different structures that can accumulate inside mitochondria and scavenge free radicals have been synthesized. Their protective role based on the prevention of oxidative stress and the restoration of mitochondrial function has been demonstrated in a variety of common diseases and pathological states. This paper reviews the current data on the beneficial application of different mito-AOX in animal endotoxemia models, in either in vivo or in vitro experiments. The results presented in our review demonstrate the promising potential of approaches based on mito-AOX in the development of new treatment strategies against Gram-negative infections and LPS per se.