Eupalinolide B attenuates lipopolysaccharide-induced acute lung injury through inhibition of NF-κB and MAPKs signaling by targeting TAK1 protein

Eupalinolide B targets DEK and PANoptosis through E3 ubiquitin ligases RNF149 and RNF170 to negatively regulate asthma

PURPOSE

We investigated the mechanism by which eupalinolide B (EB) regulates DEK protein ubiquitination and degradation, and its impact on DEK-mediated receptor-interacting protein kinase 1 (RIPK)-PANoptosis pathway in allergic asthma.

STUDY DESIGN AND METHODS

In vitro studies were conducted on human bronchial epithelial cells (BEAS-2B) treated with EB and human-recombinant DEK. Mass spectrometry analysis, RNA sequencing, molecular docking, and functional assays were used to assess the interactions and effects of EB, DEK, and ring finger protein 149 and 170 (RNF149 and RNF170). In vivo experiments involved a house dust mite-induced asthma model in mice and evaluation of airway inflammation, DEK expression, and PANoptosis markers.

RESULTS

In vitro, EB could bind to DEK. RNF149 and RNF170 were identified as regulatory factors of DEK, polyubiquitinating the K349 site in the DEK coding DNA sequence region 270-350 through K48 linkages and leading to its degradation. RNA sequencing showed that DEK overexpression upregulated the expression of genes such as RIPK1, FADD, and Caspase 8. Treatment with DEK siRNA or EB reduced the activation of the RIPK1-PANoptosis pathway in BEAS-2B-DEK cells. In vivo, EB significantly reduced the levels of DEK in house dust mite-induced mice and alleviated pulmonary inflammatory cell infiltration, goblet cell hyperplasia, collagen fiber deposition, and eosinophil proportion in BALF. Knocking out the DEK gene reduced RIPK1-induced PANoptosis, and inhibited airway inflammation and cell apoptosis.

CONCLUSION

EB promotes the degradation of DEK by RNF149 and RNF170, inhibits the RIPK1-PANoptosis pathway, and may effectively suppress asthma. EB may become a potential drug for treating airway inflammation in asthma.

Eupalinolide B alleviates corticosterone-induced PC12 cell injury and improves depression-like behaviors in CUMS rats by regulating the GSK-3β/β-catenin pathway

Eupalinolide B (EB), a primary bioactive compound isolated from Eupatorium lindleyanum DC., has exhibited various pharmacological properties, such as antitumor, anti-inflammatory, and notably, neuroprotective effects in neurodegenerative diseases. However, the in-depth studies on the antidepressant potential of EB and its underlying mechanisms are still lacking. Herein, we investigated the therapeutic effects of EB on corticosterone (CORT)-induced neurotoxicity in PC12 cells and its antidepressant-like effects in rats subjected to chronic unpredictable mild stress (CUMS). In particular, we focused on the molecular mechanisms related to modulating the GSK-3β/β-catenin pathway. Our findings revealed that EB promoted cell proliferation while decreasing apoptosis and oxidative stress in CORT-induced PC12 cells. In vivo, EB alleviated the depressive-like behaviors in CUMS rats, as assayed by the sucrose preference test, open field test, and forced swim test. Additionally, EB attenuated the hippocampal pathological damage and increased Ki67- and doublecortin-positive cell numbers in hippocampal dentate gyrus, thus restoring hippocampal neurogenesis in CUMS rats. The binding of EB to GSK-3β was confirmed using molecular docking and cellular thermal shift assays. Overexpression of GSK-3β diminished the therapeutic effects of EB on CORT-induced PC12 cells, further indicating that GSK-3β is the target of EB. Mechanistically, EB hindered GSK-3β activity and thus activated β-catenin signaling in both CORT-induced PC12 cells and CUMS rat hippocampus, as demonstrated by increased p-GSK-3β (Ser9), reduced p-β-catenin, and elevated β-catenin expression. Collectively, this study offers new insights into the antidepressant mechanisms of EB, highlighting its potential as a candidate for depression treatment.

TAK1-mediated phosphorylation of PLCE1 represses PIP2 hydrolysis to impede esophageal squamous cancer metastasis

TAK1 is a serine/threonine protein kinase that is a key regulator in a wide variety of cellular processes. However, the functions and mechanisms involved in cancer metastasis are still not well understood. Here, we found that TAK1 knockdown promoted esophageal squamous cancer carcinoma (ESCC) migration and invasion, whereas TAK1 overexpression resulted in the opposite outcome. These in vitro findings were recapitulated in vivo in a xenograft metastatic mouse model. Mechanistically, co-immunoprecipitation and mass spectrometry demonstrated that TAK1 interacted with phospholipase C epsilon 1 (PLCE1) and phosphorylated PLCE1 at serine 1060 (S1060). Functional studies revealed that phosphorylation at S1060 in PLCE1 resulted in decreased enzyme activity, leading to the repression of phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis. As a result, the degradation products of PIP2 including diacylglycerol (DAG) and inositol IP3 were reduced, which thereby suppressed signal transduction in the axis of PKC/GSK-3β/β-Catenin. Consequently, expression of cancer metastasis-related genes was impeded by TAK1. Overall, our data indicate that TAK1 plays a negative role in ESCC metastasis, which depends on the TAK1-induced phosphorylation of PLCE1 at S1060.

Eupalinolide B alleviates rheumatoid arthritis through the promotion of apoptosis and autophagy via regulating the AMPK/mTOR/ULK-1 signaling axis

The excessive proliferation of fibroblast-like synoviocytes (FLS) leads to synovial hyperplasia, a key pathological hallmark of rheumatoid arthritis (RA). Eupalinolide B (EB), a sesquiterpene lactone of Eupatorium lindleyanum DC., has anti-inflammatory effects and anti-proliferative activity in tumor cells. However, its potential use in RA treatment is unclear. This study explored EB's anti-rheumatoid activities by promoting apoptosis and autophagy in RA-FLS and the synovium of adjuvant-induced arthritis (AIA) rats, focusing on its regulation of the AMPK/mTOR/ULK-1 axis. Our findings revealed that EB inhibited proliferation, induced apoptosis, and promoted autophagy in RA-FLS. Autophagy inhibition using 3-methyladenine (3-MA) diminished EB's anti-proliferative effects, suggesting that EB promotes RA-FLS autophagy as a death mechanism. Z-VAD-FMK, a pan-caspase inhibitor, decreased EB-induced autophagy, while 3-MA co-treatment reduced caspase-3 activity, demonstrating that EB-induced apoptosis and autophagy promoted each other to support its anti-proliferative effects. In vivo, EB exhibited clear anti-arthritic effects in AIA rats, as shown by reduced paw swelling, arthritis index, serum levels of TNF-α, IL-1β, and MCP-1, and joint damage, along with decreased Ki67 expression, increased apoptosis, and enhanced autophagy in AIA rat synovium. Mechanistically, EB regulated the AMPK/mTOR/ULK-1 axis in RA-FLS and AIA rat synovium, as evidenced by higher expression of p-AMPK and p-ULK-1 and lower levels of p-mTOR. Notably, co-treatment of the AMPK inhibitor compound C negated EB's beneficial effects in RA-FLS and AIA rats. Collectively, EB demonstrated exact anti-RA effects by inducing apoptosis and autophagy via the regulation of the AMPK/mTOR/ULK-1 axis, highlighting its potential for RA therapy.

Sesquiterpene Lactones as Promising Anti-Glioblastoma Drug Candidates Exerting Complex Effects on Glioblastoma Cell Viability and Proneural-Mesenchymal Transition

Glioblastoma is one of the most aggressive brain cancers, characterized by active infiltrative growth and high resistance to radiotherapy and chemotherapy. Sesquiterpene triterpenoids (STLs) and their semi-synthetic analogs are considered as a promising source of novel anti-tumor agents due to their low systemic toxicity and multi-target pharmacological effects on key processes associated with tumor progression. The current review aims to systematize the knowledge on the anti-glioblastoma potential of STLs accumulated over the last decade and to identify key processes in glioblastoma cells that are most susceptible to the action of STLs. An analysis of published data clearly demonstrated that STLs, which can successfully cross the blood-brain barrier, exert a complex inhibitory effect on glioblastoma cells through the induction of the "mitochondrial dysfunction-oxidative stress-apoptosis" axis, the inhibition of glucose metabolism and cell cycle phase transition, and the suppression of glioblastoma cell motility and invasion through the blockade of proneural-mesenchymal transition. Taken together, this review highlights the promising anti-glioblastoma potential of STLs, which are not only able to induce glioblastoma cell death, but also effectively affect their diffusive spread, and suggests the possible directions for further investigation of STLs in the context of glioblastoma to better understand their mechanism of action.

Eupalinolide B inhibits periodontitis development by targeting ubiquitin conjugating enzyme UBE2D3

Periodontitis is a chronic periodontal inflammatory disease caused by periodontal pathogens commonly seen in adults. Eupalinolide B (EB) is a sesquiterpenoid natural product extracted from Eupatorium lindleyanum and has been reported as a potential drug for cancers and immune disorders. Here, we explored the ameliorative effects and underlying molecular mechanism of EB on periodontitis for the first time. We demonstrated that EB ameliorates periodontal inflammation and alveolar bone resorption with a ligated periodontitis mouse model. In addition, the impact of EB on macrophages inflammation was examined in the Raw264.7 cell line. We identified ubiquitin-conjugating enzyme, UBE2D3, as the direct covalent binding protein targets of EB by using a chemoproteomic method based on activity-based protein profiling, biolayer interferometry method, and cellular thermal shift assay. Furthermore, the direct binding site of EB to UBE2D3 was identified using high-resolution mass spectrometry and confirmed by experiments. Taken together, EB ameliorates periodontitis by targeting UBE2D3 to suppress the ubiquitination degradation of IκBα, leading to inactivation of nuclear transcription factor-κB signaling pathway. And this was confirmed by siRNA-mediated gene knockdown in inflammatory macrophages. Our results suggested that EB may be a new kind of UBE2D3 inhibitor and may become a promising therapeutic agent for anti-periodontitis.

Eupalinolide B suppresses pancreatic cancer by ROS generation and potential cuproptosis

Pancreatic cancer is highly lethal with limited effective treatments. This study explores the therapeutic effects of eupalinolide B (EB) from Eupatorium lindleyanum DC on pancreatic cancer cells. Through cellular functional assays, we observed that EB effectively inhibits cell viability, proliferation, migration, and invasion. In a xenograft mouse model, EB treatment resulted in reduced pancreatic cancer tumor growth and decreased expression of Ki-67. Mechanistically, EB induces apoptosis, elevates reactive oxygen species (ROS) levels, and disrupts copper homeostasis. RNA sequencing (RNA-seq) and gene set enrichment analysis (GSEA) identified copper ion binding pathways and potential involvement in cuproptosis. Furthermore, EB enhances the cytotoxic effects of elesclomol (ES), increasing ROS levels in a copper-dependent manner and exhibiting synergistic cytotoxicity. These findings suggest that EB, either alone or in combination with ES, represents a promising strategy for targeting metal ion dysregulation and inducing potential cuproptosis in pancreatic cancer, offering a potential improvement in therapeutic outcomes.

Homoplantaginin alleviates intervertebral disc degeneration by blocking the NF-κB/MAPK pathways via binding to TAK1

Intervertebral disc degeneration (IVDD) is a common degenerative disease which is closely related to low back pain (LBP) and brings huge economic and social burdens. In this study, we explored the therapeutic effects of Homoplantaginin (Hom) for IVDD due to its convincing anti-inflammatory and antioxidant functions. TNF-α was used to simulate the inflammatory environment for nucleus pulposus (NP) cells in vitro. We verified that Hom could alleviate the TNF-α-induced inflammation and disturbance of ECM homeostasis through blocking the NF-κB/MAPK signaling pathways. Subsequently, we screened the binding targets of Hom and confirmed that Hom could directly bind to TAK1 and inhibit its phosphorylation to down-regulate the inflammation-related pathways. The therapeutic effects of Hom on IVDD were further validated through a needle puncture rat model in vivo. Overall, Hom was a promising small molecule for IVDD early intervention, possessing huge clinical translational value.

Echinatin attenuates acute lung injury and inflammatory responses via TAK1-MAPK/NF-κB and Keap1-Nrf2-HO-1 signaling pathways in macrophages

Echinatin is an active ingredient in licorice, a traditional Chinese medicine used in the treatment of inflammatory disorders. However, the protective effect and underlying mechanism of echinatin against acute lung injury (ALI) is still unclear. Herein, we aimed to explore echinatin-mediated anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated ALI and its molecular mechanisms in macrophages. In vitro, echinatin markedly decreased the levels of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated murine MH-S alveolar macrophages and RAW264.7 macrophages by suppressing inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) expression. Furthermore, echinatin reduced LPS-induced mRNA expression and release of interleukin-1β (IL-1β) and IL-6 in RAW264.7 cells. Western blotting and CETSA showed that echinatin repressed LPS-induced activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) pathways through targeting transforming growth factor-beta-activated kinase 1 (TAK1). Furthermore, echinatin directly interacted with Kelch-like ECH-associated protein 1 (Keap1) and activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway to enhance heme oxygenase-1 (HO-1) expression. In vivo, echinatin ameliorated LPS-induced lung inflammatory injury, and reduced production of IL-1β and IL-6. These findings demonstrated that echinatin exerted anti-inflammatory effects in vitro and in vivo, via blocking the TAK1-MAPK/NF-κB pathway and activating the Keap1-Nrf2-HO-1 pathway.

Low shear stress induces macrophage infiltration and aggravates aneurysm wall inflammation via CCL7/CCR1/TAK1/ NF-κB axis

BACKGROUND

This study aimed to elucidate the mechanism by which wall shear stress (WSS) influences vascular walls, accounting for the susceptibility of intracranial aneurysms (IAs) to rupture.

METHOD

We collected blood samples from the sacs of 24 ruptured and 28 unruptured IAs and analyzed the expression of chemokine CCL7 using enzyme-linked immunosorbent assay (ELISA). Univariate and multivariate logistic regression analyses were employed to assess clinical data, aneurysm morphology, and hemodynamics in both groups. Pearson correlation analysis investigated the relationship between CCL7 expression in aneurysm sac blood and WSS. Additionally, we established a bionic cell parallel plate co-culture shear stress model and a mouse low shear stress (LSS) model. The model was modulated using CCL7 recombinant protein, CCR1 inhibitor, and TAK1 inhibitor. We further evaluated CCL7 expression in endothelial cells and the levels of TAK1, NF-κB, IL-1β, and TNF-α in macrophages. Subsequently, the intergroup differences in expression were calculated.

RESULTS

CCL7 expression was significantly higher in the ruptured group compared to the unruptured group. Hemodynamic analysis indicated that WSS was an independent predictor of the risk of aneurysm rupture. A negative linear correlation was observed between CCL7 expression and WSS. Upon addition of CCL7 recombinant protein, upregulation of CCR1 expression and increased levels of p-TAK1 and p-p65 were observed. Treatment with CCR1 and TAK1 inhibitors reduced inflammatory cytokine expression in macrophages under LSS conditions. Overexpression of TAK1 significantly alleviated the inhibitory effects of CCR1 inhibitors on p-p65 and inflammatory cytokines.

CONCLUSION

LSS prompts endothelial cells to secrete CCL7, which, upon binding to the macrophage surface receptor CCR1, stimulates the release of macrophage inflammatory factors via the TAK1/NF-κB signaling pathway. This process exacerbates aneurysm wall inflammation and increases the risk of aneurysm rupture.

SP-8356 inhibits acute lung injury by suppressing inflammatory cytokine production and immune cell infiltration

This study investigated the anti-inflammatory and protective properties of SP-8356, a synthetic derivative of (1S)-(-)-verbenone, in a mouse model of LPS-induced acute lung injury (ALI). By targeting intracellular signaling pathways and inflammatory responses, SP-8356 demonstrated a potent ability to attenuate deleterious effects of proinflammatory stimuli. Specifically, SP-8356 effectively inhibited the activation of crucial signaling molecules such as NF-κB and Akt, and subsequently dampened the expression of inflammatory cytokines in various lung cellular components. Intervention with SP-8356 treatment also preserved the structural integrity of the epithelial and endothelial barriers. By reducing immune cell infiltration into inflamed lung tissue, SP-8356 exerted a broad protective effect against ALI. These findings position SP-8356 as a promising therapeutic candidate for pulmonary inflammatory diseases that cause ALI.

Rosavin Alleviates LPS-Induced Acute Lung Injure by Modulating the TLR-4/NF-κB/MAPK Singnaling Pathways

Acute lung injury (ALI) is a serious inflammatory disease with high morbidity and mortality. Rosavin is an anti-inflammatory and antioxidant phenylpropanoid and glucoside, which is isolated from Rhodiola rosea L. However, its potential molecular mechanisms and whether it has protective effects against lipopolysaccharide (LPS)-induced ALI remain to be elucidated. To assess the in vitro anti-inflammatory effects and anti-lung injury activity of rosavin, RAW264.7 and A549 cells were stimulated using 1 μg/mL LPS. Rosavin attenuated LPS-induced activation of the TLR-4/NF-κB signaling pathway in RAW264.7 cells and inhibited LPS-induced release of inflammatory factors in A549 cells. A mouse model of acute lung injury was constructed by intraperitoneal injection of 5 mg/kg LPS to observe the therapeutic effect of rosavin. Transcriptomics analysis and Western blot assays were utilized to verify the molecular mechanism, rosavin (20, 40, and 80 mg/kg) dose-dependently ameliorated histopathological alterations, reduced the levels of inflammatory factors, and inhibited the TLR-4/NF-κB/MAPK signaling pathway and apoptosis activation. Rosavin is a promising therapeutic candidate for acute lung injury by inhibiting the TLR-4/NF-κB/MAPK pathway.

Arteannuin B, a sesquiterpene lactone from Artemisia annua, attenuates inflammatory response by inhibiting the ubiquitin-conjugating enzyme UBE2D3-mediated NF-κB activation

BACKGROUND

Anomalous activation of NF-κB signaling is associated with many inflammatory disorders, such as ulcerative colitis (UC) and acute lung injury (ALI). NF-κB activation requires the ubiquitination of receptor-interacting protein 1 (RIP1) and NF-κB essential modulator (NEMO). Therefore, inhibition of ubiquitation of RIP1 and NEMO may serve as a potential approach for inhibiting NF-κB activation and alleviating inflammatory disorders.

PURPOSE

Here, we identified arteannuin B (ATB), a sesquiterpene lactone found in the traditional Chinese medicine Artemisia annua that is used to treat malaria and inflammatory diseases, as a potent anti-inflammatory compound, and then characterized the putative mechanisms of its anti-inflammatory action.

METHODS

Detections of inflammatory mediators and cytokines in LPS- or TNF-α-stimulated murine macrophages using RT-qPCR, ELISA, and western blotting, respectively. Western blotting, CETSA, DARTS, MST, gene knockdown, LC-MS/MS, and molecular docking were used to determine the potential target and molecular mechanism of ATB. The pharmacological effects of ATB were further evaluated in DSS-induced colitis and LPS-induced ALI in vivo.

RESULTS

ATB effectively diminished the generation of NO and PGE2 by down-regulating iNOS and COX2 expression, and decreased the mRNA expression and release of IL-1β, IL-6, and TNF-α in LPS-exposed RAW264.7 macrophages. The anti-inflammatory effect of ATB was further demonstrated in LPS-treated BMDMs and TNF-α-activated RAW264.7 cells. We further found that ATB obviously inhibited NF-κB activation induced by LPS or TNF-α in vitro. Moreover, compared with ATB, dihydroarteannuin B (DATB) which lost the unsaturated double bond, completely failed to repress LPS-induced NO release and NF-κB activation in vitro. Furthermore, UBE2D3, a ubiquitin-conjugating enzyme, was identified as the functional target of ATB, but not DATB. UBE2D3 knockdown significantly abolished ATB-mediated inhibition on LPS-induced NO production. Mechanistically, ATB could covalently bind to the catalytic cysteine 85 of UBE2D3, thereby inhibiting the function of UBE2D3 and preventing ubiquitination of RIP1 and NEMO. In vivo, ATB treatment exhibited robust protective effects against DSS-induced UC and LPS-induced ALI.

CONCLUSION

Our findings first demonstrated that ATB exerted anti-inflammatory functions by repression of NF-κB pathway via covalently binding to UBE2D3, and raised the possibility that ATB could be effective in the treatment of inflammatory diseases and other diseases associated with abnormal NF-κB activation.

TIPE3 protects mice from lipopolysaccharide-induced acute lung injury

BACKGROUND

Acute lung injury (ALI) is a severe inflammatory disease with high morbidity and mortality in patients and lung transplant recipients. Tumor necrosis factor-α-induced protein 8-like 3 (TIPE3) is one of the members of the TIPE family. While TIPE2 has been demonstrated to be protective against lipopolysaccharide (LPS)-induced ALI, the role of TIPE3 in ALI is currently unidentified.

METHODS

To examine the role of TIPE3 in ALI, we pretreated C57BL/6 mice with control or TIPE3-lentivirus in LPS-induced ALI models. The C57BL/6 mice were randomly divided into four groups: control group; ALI-induced group; ALI-induced group with control lentivirus; and ALI-induced group with TIPE3-lentivirus. Additionally, RAW 264.7 cells were used to validate the role and molecular mechanism of TIPE3 signaling in vitro.

RESULTS

An increased expression of TIPE3 reduced lung histopathological damage in ALI-affected mice. ALI-affected mice treated with TIPE3-lentivirus exhibited reduced lung microvascular permeability, myeloperoxidase (MPO) activity, neutrophil buildup, and inflammation response. Additionally, over-expression of TIPE3 significantly inhibited NF-κB activation and promoted the activation of Liver X receptors alpha (LXRα). In LPS-treated RAW264.7 cells, enforced TIPE3 expression produced anti-inflammatory effects, whereas the LXR inhibitor geranylgeranyl pyrophosphate (GGPP) reversed these effects.

CONCLUSIONS

TIPE3 protected against LPS-induced ALI by regulating the LXRα/NF-κB signaling pathway. These results suggest that TIPE3 might provide a novel insight into the prevention of ALI.

Characterization of the metabolism of eupalinolide A and B by carboxylesterase and cytochrome P450 in human liver microsomes

Eupalinolide A (EA; Z-configuration) and eupalinolide B (EB; E-configuration) are bioactive cis-trans isomers isolated from Eupatorii Lindleyani Herba that exert anti-inflammatory and antitumor effects. Although one pharmacokinetic study found that the metabolic parameters of the isomers were different in rats, metabolic processes relevant to EA and EB remain largely unknown. Our preliminary findings revealed that EA and EB are rapidly hydrolyzed by carboxylesterase. Here, we investigated the metabolic stability and enzyme kinetics of carboxylesterase-mediated hydrolysis and cytochrome P450 (CYP)-mediated oxidation of EA and EB in human liver microsomes (HLMs). We also explored differences in the hydrolytic stability of EA and EB in human liver microsomes and rat liver microsomes (RLMs). Moreover, cytochrome P450 reaction phenotyping of the isomers was performed via in silico methods (i.e., using a quantitative structure-activity relationship model and molecular docking) and confirmed using human recombinant enzymes. The total normalized rate approach was considered to assess the relative contributions of five major cytochrome P450s to EA and EB metabolism. We found that EA and EB were eliminated rapidly, mainly by carboxylesterase-mediated hydrolysis, as compared with cytochrome P450-mediated oxidation. An inter-species difference was observed as well, with faster rates of EA and EB hydrolysis in rat liver microsomes. Furthermore, our findings confirmed EA and EB were metabolized by multiple cytochrome P450s, among which CYP3A4 played a particularly important role.