Glaucocalyxin A alleviates LPS-mediated septic shock and inflammation via inhibiting NLRP3 inflammasome activation

Pyroptosis in sepsis induced organ dysfunction

As an uncontrolled inflammatory response to infection, sepsis and sepsis induced organ dysfunction are great threats to the lives of septic patients. Unfortunately, the pathogenesis of sepsis is complex and multifactorial, which still needs to be elucidated. Pyroptosis is a newly discovered atypical form of inflammatory programmed cell death, which depends on the Caspase-1 dependent classical pathway or the non-classical Caspase-11 (mouse) or Caspase-4/5 (human) dependent pathway. Many studies have shown that pyroptosis is related to sepsis. The Gasdermin proteins are the key molecules in the membrane pores formation in pyroptosis. After cut by inflammatory caspase, the Gasdermin N-terminal fragments with perforation activity are released to cause pyroptosis. Pyroptosis is closely related to the occurrence and development of sepsis induced organ dysfunction. In this review, we summarized the molecular mechanism of pyroptosis, the key role of pyroptosis in sepsis and sepsis induced organ dysfunction, with the aim to bring new diagnostic biomarkers and potential therapeutic targets to improve sepsis clinical treatments.

Dimeric ent-kauranoids isolated from Isodon japonica var. Glaucocalyx and their anti-inflammatory activities

The phytochemical investigation of the aerial parts of Isodon japonica var. glaucocalyx afforded four undescribed (glaucocalyxin O-R, 1-4) and six known ent-kauranoids (5-10). Their structures were established using NMR and MS measurements. Compounds 1 and 2 are dimeric ent-kaurane-type diterpenoids. Moreover, the plausible biogenetic pathways for compounds 1 and 2 were proposed as Michael addition between two monomers. Eight compounds were assayed for their anti-inflammatory activity by evaluating NO production in LPS-induced RAW 267.4 cells, and compounds 7, 8 and 9 exhibited relatively remarkable anti-inflammatory activities at 10 μM.

Glaucocalyxin A delays the progression of OA by inhibiting NF-κB and MAPK signaling pathways

BACKGROUND

Osteoarthritis (OA) is a common degenerative joint condition marked by inflammation and cartilage breakdown. Currently, there is a dearth of treatment medications that can clearly slow the course of OA. Glaucocalyxin A (GLA) is a diterpene chemical identified and extracted from Rabdosia japonica with antithrombotic, anticoagulant, anti-tumor, anti-inflammatory, anti-oxidant, and other pharmacological properties. Previous research has linked inflammation to abnormalities in the homeostasis of the extracellular matrix (ECM). Although GLA has been shown to have anti-inflammatory qualities, its effects on the progression of OA are unknown. As a result, the goal of this study was to see if GLA could slow the course of OA.

METHODS

ATDC5 cells were stimulated by IL-1β to create an inflammatory chondrocyte damage model. Quantitative polymerase chain reaction, Western Blot, high-density culture, and immunofluorescence were used to detect the expression levels of associated gene phenotypes. We also created a mouse model of OA induced by destabilization of the medial meniscus (DMM) instability, and GLA was administered intraperitoneally once every two days for eight weeks. Mice knee specimens were stained with hematoxylin-eosin, Safranin O/fast green, and immunohistochemical, and the Osteoarthritis Research Society International grade system and Mankin's score were used to assess the protective effect of GLA on cartilage.

RESULTS

In vitro and in vivo, we explored the effects and molecular processes of GLA as a therapy for OA. The findings demonstrated that GLA might reduce the expression of associated inflammatory mediators and protect the ECM by inhibiting the NF-κB and MAPK signaling pathways. Animal research revealed that GLA could protect against the DMM-induced OA model mice by stabilizing ECM.

CONCLUSION

Taken together, our findings show that GLA has a protective impact on cartilage throughout OA progression, implying that GLA could be employed as a possible therapeutic agent for OA, thus giving a new therapeutic method for the treatment of OA.

Ciclopirox mitigates inflammatory response in LPS-induced septic shock via inactivation of SORT1-mediated wnt/β-Catenin signaling pathway

OBJECTIVE

Septic shock, the most severe stage of sepsis, is a deadly inflammatory disorder with high mortality. Ciclopirox (CPX) is a broad-spectrum antimycotic agent which also exerts anti-inflammatory effects in human diseases. However, whether CPX can relieve inflammatory response in LPS-induced septic shock remains unclear.

MATERIALS AND METHODS

Male C57BL/6 mice LPS were injected intraperitoneally with LPS to simulate septic shock in vivo. RAW264.7 cells and bone marrow-derived macrophages (BMDMs) were subject to LPS treatment to simulate septic shock in vitro. ELISA was applied to detect the level of pro-inflammatory cytokines. Cell viability was assessed by CCK-8 assay. Protein levels was detected by western blotting.

RESULTS

CPX enhanced the survival rate and attenuated inflammation in mice with LPS-induced septic shock. Similarly, CPX dose-dependently mitigated LPS-induced inflammation in BMDMs. It was also found that Sortilin 1 (SORT1) was upregulated in both in vivo and in vitro models of LPS-induced septic shock. In addition, SORT1 overexpression counteracted the alleviative effects of CPX on the inflammation response of LPS-challenged BMDMs by activating the Wnt/β-Catenin signaling. Furthermore, BML-284 (a Wnt/β-Catenin agonist) treatment also abrogated CPX-mediated moderation of LPS-triggered inflammatory reaction in BMDMs.

CONCLUSIONS

In sum, we found that CPX protected against LPS-induced septic shock by mitigating inflammation via SORT1-mediated Wnt/β-Catenin signaling pathway.

Glaucocalyxin A attenuates carbon tetrachloride-induced liver fibrosis and improves the associated gut microbiota imbalance

Liver fibrosis refers to the pathophysiological process of dysplasia on the connective tissue of the liver, caused by a variety of pathogenic factors. Glaucocalyxin A (GLA) has anticoagulation, antibacterial, anti-inflammation, antioxidant and antitumour properties. However, whether GLA ameliorates liver fibrosis or not is still unclear. In this study, a liver fibrosis model was established using male C57BL/6 mice. The mice were treated with 5 and 10 mg/kg GLA via intraperitoneal injection, respectively. The ones that were treated with 5 mg/kg OCA were used as the positive control group. The levels of liver function, liver fibrosis biomarkers and liver pathological changes were then evaluated. We also explored the effects of GLA on inflammatory response and liver cell apoptosis. In addition, we investigated the gut microbiota mechanisms of GLA on liver fibrosis. The results from this study that GLA could significantly decrease the level of liver function (AST, ALT, TBA) and liver fibrosis (HA, LN, PC-III, IV-C). On the other hand, a significant decrease in inflammation levels (IL-1β, TNF-α) were also noted. GLA also improves CCl4-induced pathological liver injuries and collagen deposition, in addition to decreasing apoptosis levels. In addition, an increase in the ratio of Bacteroidetes and Firmicutes in liver disease was also observed. GLA also improves the gut microbiota. In conclusion, GLA attenuates CCl4-induced liver fibrosis and improves the associated gut microbiota imbalance.

Parthenolide targets NLRP3 to treat inflammasome-related diseases

Natural products have attracted extensive attention from researchers in medical fields due to their abundant biological activities. Parthenolide (PTL) is a sesquiterpene lactone originally purified from herb Feverfew (Tanacetum parthenium), recent studies have showed its potential activities of anti-cancer and anti-inflammatory. Acting as the most studied inflammasome, NLRP3 inflammasome played an important role in human diseases including type-2 diabetes (T2D), Alzheimer's disease (AD) and cryopyrin-associated periodic syndromes (CAPS). In this article, we show that PTL specially inhibits the activation of NLRP3 inflammation by block the upstream signal and prevent the assembly of NLRP3 inflammasome complex. Furthermore, we showed the treatment of PTL significantly attenuates the symptoms of lipopolysaccharide (LPS)-induced systemic inflammation and dextran sulfate sodium (DSS)-induced colitis in mice models. Thus, our results demonstrate that PTL alleviates inflammation by targeting NLRP3 inflammasome, which indicate that PTL acting as a promising natural product for the treatment of NLRP3 inflammasome-related diseases.

Protective effects of glaucocalyxin A on the airway of asthmatic mice

The aim of this study is to investigate the protective effects of glaucocalyxin A (GLA) on airways in mouse models of asthma, concerning the inflammatory mediators, Th1/Th2 subgroup imbalance, and Toll-like receptor 4 (TLR4)/NF-κB signaling pathway. Hematoxylin and eosin/periodic acid–Schiff staining was used to observe the pathological changes in lung tissues. Inflammatory cytokine contents in the bronchoalveolar lavage fluid were detected by enzyme-linked immunosorbent assay. Protein expression levels were detected with Western blot, immunohistochemistry, and immunofluorescence. In vivo studies showed that, in ovalbumin (OVA)-induced asthmatic mouse models, the GLA treatments reduced the airway hyperresponsiveness and the secretion of inflammatory cells, declined the proliferation of goblet cells, decreased the levels of IL-4, IL-5, and IL-13, and increased the contents of interferon-γ and IL-12. Moreover, GLA inhibited the protein expression levels of TLR4, MyD88, TRAF6, and NF-κB in OVA-induced asthmatic mouse models. Further in vitro studies showed that GLA inhibited the expression of NF-κB, p-IκBα, tumor necrosis factor-α, IL-6, and IL-1β and blocked the nuclear transfer of NF-κB in lipopolysaccharide-stimulated RAW264.7 macrophages. Conclusively, GLA can inhibit the inflammatory responses in OVA-induced asthmatic mice and inhibit the release of inflammatory factors in LPS-induced RAW264.7 macrophages, which may be related to the inhibition of TLR4/NF-κB signaling pathway.

Glaucocalyxin a protect liver function via inhibiting platelet over-activation during sepsis

BACKGROUND

Rabdosia japonica (Burm. f.) var. glaucocalyx (Maxim.) is a perennial herb, and is traditionally used as folk medicine for treating inflammatory diseases and cancer. Gaucocalyxin A (GLA) is an ent‑kaurane diterpenoid that is isolated from the aerial parts of R. japonica (Burm. f.) var. glaucocalyx (Maxim.). In a recent study, we found that GLA protects against acute liver dysfunction induced by Escherichia coli, which is likely related to its anti-inflammatory effects. However, the mechanism by which GLA protects liver injury during sepsis is unknown.

AIM

To evaluate the anti-inflammatory function of GLA and its regulatory effect on platelet function.

METHOD

An in vivo model of sepsis was established by inoculating mice with E. coli. Live function and platelet activation were evaluated through standard assays. The levels of pro-inflammatory factors were measured through ELISA and qRT-PCR.

RESULTS

GLA alleviated liver dysfunction in the mouse model of sepsis. GLA-treated mice displayed lower complement activation and liver dysfunction after E. coli infection. GLA alleviated the decrease in peripheral platelet counts by inhibiting their clearance by Kupffer cells in liver. Furthermore, GLA inhibited platelet activation through the RIP1/RIP3/AKT pathway and downregulated C3aR expression on the platelets, thereby inhibiting liver injury and dysfunction due to excessive complement activation.

CONCLUSION

GLA can inhibit platelet activation by reducing surface expression of C3aR, which protect the liver from injury induced by excessive complement activation. GLA is a novel therapeutic agent for controlling sepsis-related liver dysfunction.

Necroptosis, Pyroptosis, Ferroptosis in Sepsis and Treatment

ABSTRACT

As a global major health problem and a leading cause of death, sepsis is defined as a failure of homeostasis, which is mainly initiated by an infection and followed by sustained excessive inflammation until immune suppression. Despite advances in the identification and management of clinical sepsis, morbidity, and mortality remain high. In addition, clinical trials have failed to yield promising results. In recent years, the mechanism of regulated cell death (RCD) in sepsis has attracted more and more attention, because these dying cells could release a large number of danger signals which contribute to inflammatory responses and exacerbation of sepsis, providing a new direction for us to make treatment strategy. Here we summarize mechanisms of several forms of RCD in sepsis including necroptosis, pyroptosis, ferroptosis. In conclusion, targeting RCD is considered a promising approach to treat sepsis.

Glaucocalyxin A induces apoptosis of NSCLC cells by inhibiting the PI3K/Akt/GSK3β pathway

Lung cancer is one of the fastest growing malignancies in morbidity and mortality, and current therapies are in general not sufficiently effective for this deadly disease. This study characterizes the anti-cancer effects of Glaucocalyxin A (GLA) and explores the underlying mechanisms using human non-small cell lung carcinoma (NSCLC) cells. First, our data showed that GLA suppressed the viability of cancer cells, while no effect was observed in the normal bronchial epithelial cell Bease 2B cells. Second, GLA inhibited colony formation, induced apoptosis of cancer cells. Third, GLA down-regulated the expression of B-cell lymphoma-2 (Bcl-2) protein, up-regulated the expression of Bcl2-associated X protein (Bax) , and strengthened cleavage of Caspase-3 and poly ADP-ribose polymerase (PARP). Fourth, GLA also diminished mitochondrial membrane potential and inhibited phosphatidylinositol 3-kinase (PI3K)/Akt/ glycogen synthase kinase-3β (GSK3β) pathway. In addition, injection of GLA (20 mg/kg) every two days significantly inhibited A549 xenograft tumor growth, accompanied by increased apoptosis and decreased proliferation. Together, our study provides evidence that the anticancer effect of GLA in NSCLC is mediated by inducing apoptosis through inhibiting PI3K/Akt/GSK3β pathway and suggests that GLA may be used as a promising natural medicine for NSCLC therapy. This article is protected by copyright. All rights reserved.

Tectoridin alleviates lipopolysaccharide -induced inflammaion via inhibiting TLR4-NF-κB/NLRP3 signaling in vivo and in vitro

BACKGROUD

Tectoridin, widely extracted and separated from the rhizome of Iris tectorum Maxium, is extensively reported to have affluent bioactivity, but rarely reported to have anti-inflammatory effects. In this study, we aim to investigate the anti-inflammatory effects and the underlying mechanisms of tectoridin.

METHODS

Here, RAW264.7 macrophages were stimulated with Lipopolysaccharide (LPS) for the inflammation model in vitro. Experimental animals received tectoridin and Dexamethasone (DEX) before LPS injection for endotoxic shock mouse model in vivo. The pro-inflammatory mediators and cytokines in the cell supernatant and serum were detected by ELISA kits. The tissue damages were assessed by biochemical indexes and H&E staining. Immunohistochemistry and Western blot were performed for the detection of proteins.

RESULTS

Our data showed that tectoridin attenuated the LPS-up-regulated nitric oxide (NO), interleukin-6, (IL-6) and interleukin-18, (IL-18) from macrophages and tumor necrosis factor-α, (TNF-α); (IL-6) and (IL-1β) in the serum levels. Besides, our histopathological study showed that the damages caused by LPS in the lung, liver and kidney tissues were decreased. Furthermore, our results demonstrated that tectoridin inhibited the activation of TLR4-NF-κB/NLRP3 signaling proved by immunohistochemistry assay and Western blot.

CONCLUSION

Taken all together, tectoridin might have the potential ability of anti-inflammatory effects and the possible mechanism may be relevant to its inhibition of TLR4-NF-κB/NLRP3 signaling.

Anti-inflammatory activity of Anchusa italica Retz. in LPS-stimulated RAW264.7 cells mediated by the Nrf2/HO-1, MAPK and NF-κB signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Anchusa italica Retz. (Boraginaceae) is an important medicinal plant for the treatment of meningitis and pneumonia in traditional Uygur medicines.

AIM OF THE STUDY

To clarify the anti-inflammatory activity of A. italica, to reveal its molecular mechanisms, and to discover the anti-inflammatory active ingredients.

MATERIALS AND METHODS

Dried and crushed aerial parts of A. italica were extracted with 75% ethanol to yield crude extract (AICE) and AICE was fractionated to obtain petroleum ether extract (AIPE), dichloromethane extract (AIDE), ethyl acetate extract (AIEE), n-butanol extract (AIBE) and residues (AIW). By measuring the effects of AIPE, AIDE, AIEE, AIBE and AIW on cell viability and nitric oxide (NO) in Lipopolysaccharide (LPS) stimulated RAW264.7 cell lines, AIDE with the lowest cytotoxicity and NO contents was finally selected for further chemical and anti-inflammatory investigations. LC-MS/MS experiment was applied to analyze the chemical composition of AIDE. MTT and Griess methods were used to detect the cell viability and to quantify the nitrite levels in culture supernatants, respectively. Prostaglandin E₂ (PGE₂), interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α) production was examined by ELISA assays. Real-time quantitative PCR was used to detect the expression of hemeoxygenase-1 (HO-1), Nrf2-mediated quinone oxidoreductase 1 (NQO-1), glutathione S-transferase A 1 (GSTA1) and glutathione S-transferase M 1 (GSTM1) mRNA. Western blot analysis was employed to examine the protein expression and enzymatic activities.

RESULTS

In preliminary anti-inflammatory screening, AIDE showed the lowest cytotoxicity and the most significant inhibitory effect on the production of NO (the inhibitory is 89%) induced by LPS among the tested five extracts. Thirty-three compounds including twenty-five triterpenoids were identified by LC-MS/MS analysis. AIDE could inhibit LPS-induced the over-expression of NO, IL-6, PGE₂, IL-1β and TNF-α and down-regulate the levels of extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), P38-MAPK (P38) and nuclear transcription factors κB-P65 (P65) phosphorylation. It promoted the mRNA expression level of HO-1, NQO-1, GSTA1 and GSTM1 and the protein expression level of nuclear factor erythroid 2-related factor 2 (Nrf2) and HO-1. After the treatment of AIDE, P65 nuclear translocation was inhibited and Nrf2 nuclear translocation was increased. In addition, the protein expression of pyrolytic relevant protein nod-like receptor family pyrin domain-containing 3 (NLRP3) and IL-1β were decreased after the AIDE treatment.

CONCLUSIONS

Anchusa italica Retz. exerted its anti-inflammatory activity by inhibiting the mitogen-activated protein kinase (MAPK), nuclear transcription factors κB (NF-κB) and pyrolytic relevant proteins, down-regulating inflammatory factor levels, and activating the Nrf2/HO-1 pathway. Triterpenoids might be its major active anti-inflammatory ingredients.

Glaucocalyxin A alleviates lipopolysaccharide‑induced inflammation and apoptosis in pulmonary microvascular endothelial cells and permeability injury by inhibiting STAT3 signaling

Glaucocalyxin A (GLA), an ent-kauranoid diterpene derived from Rabdosia japonica var. glaucocalyx, possesses antibacterial, anti-oxidative and anti-neuroinflammatory properties. The present study aimed to investigate the potential mechanisms underlying GLA in the pathogenesis of pneumonia. Human pulmonary microvascular endothelial cells (hPMVECs) treated with lipopolysaccharide (LPS) were treated with GLA, followed by the detection of cell viability, inflammation, apoptosis and cell permeability. Furthermore, the protein expression levels of apoptosis- and permeability-associated proteins were determined using western blot analysis. Following treatment with a signal transducer and activator of transcription 3 (STAT3) activator, the protein expression levels of STAT3 and endoplasmic reticulum stress-associated proteins were determined, to confirm whether STAT3 signaling was mediated by GLA. Lastly, the mRNA expression level of inflammatory cytokines, apoptosis and permeability injury were also determined following treatment with a STAT3 activator. The results revealed that GLA ameliorated inflammation, apoptosis and permeability injury in LPS-induced hPMVECs. Following treatment with a STAT3 activator, the therapeutic effects of GLA on LPS-induced hPMVECs were abrogated. In conclusion, GLA alleviated LPS-induced inflammation, apoptosis and permeability injury in hPMVECs by inhibiting STAT3 signaling, which highlighted the potential therapeutic value of GLA in the treatment of pneumonia.

Licochalcone B specifically inhibits the NLRP3 inflammasome by disrupting NEK7-NLRP3 interaction

The activation of the nucleotide oligomerization domain (NOD)-like receptor (NLR) family, pyrin domain-containing protein 3 (NLRP3) inflammasome is related to the pathogenesis of a wide range of inflammatory diseases, but drugs targeting the NLRP3 inflammasome are still scarce. In the present study, we demonstrated that Licochalcone B (LicoB), a main component of the traditional medicinal herb licorice, is a specific inhibitor of the NLRP3 inflammasome. LicoB inhibits the activation of the NLRP3 inflammasome in macrophages but has no effect on the activation of AIM2 or NLRC4 inflammasome. Mechanistically, LicoB directly binds to NEK7 and inhibits the interaction between NLRP3 and NEK7, thus suppressing NLRP3 inflammasome activation. Furthermore, LicoB exhibits protective effects in mouse models of NLRP3 inflammasome-mediated diseases, including lipopolysaccharide (LPS)-induced septic shock, MSU-induced peritonitis and non-alcoholic steatohepatitis (NASH). Our findings indicate that LicoB is a specific NLRP3 inhibitor and a promising candidate for treating NLRP3 inflammasome-related diseases.

Dihydrotanshinone I Specifically Inhibits NLRP3 Inflammasome Activation and Protects Against Septic Shock In Vivo

The abnormal activation of the NLRP3 inflammasome is closely related to the occurrence and development of many inflammatory diseases. Targeting the NLRP3 inflammasome has been considered an efficient therapy to treat infections. We found that dihydrotanshinone I (DHT) specifically blocked the canonical and non-canonical activation of the NLRP3 inflammasome. Nevertheless, DHT had no relation with the activation of AIM2 or the NLRC4 inflammasome. Further study demonstrated that DHT had no influences on potassium efflux, calcium flux, or the production of mitochondrial ROS. We also discovered that DHT suppressed ASC oligomerization induced by NLRP3 agonists, suggesting that DHT inhibited the assembly of the NLRP3 inflammasome. Importantly, DHT possessed a significant therapeutic effect on NLRP3 inflammasome–mediated sepsis in mice. Therefore, our results aimed to clarify DHT as a specific small-molecule inhibitor for the NLRP3 inflammasome and suggested that DHT can be used as a potential drug against NLRP3-mediated diseases.

Glaucocalyxin A suppresses osteoclastogenesis induced by RANKL and osteoporosis induced by ovariectomy by inhibiting the NF-κB and Akt pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Glaucocalyxin A (GLA), the most abundant active component of the aboveground sections of Rabdosia japonica (Burm. f.) Hara var. glaucocalyx (Maxim.) Hara, possesses various pharmacological activities, such as antioxidant, antithrombosis, anticoagulation, antibacterial, antitumor, anti-inflammatory activities. According to previous studies, inflammation is closely associated with osteoclast differentiation and activity. Although GLA has demonstrated effective anti-inflammatory properties, its effects on osteoclast differentiation remain unclear.

AIM OF THE STUDY

To examine the possible inhibitory effects of GLA and its molecular mechanisms in osteogenesis induced by RANKL as well as ovariectomy (OVX)-induced osteoporosis (OP) in mice.

MATERIALS AND METHODS

Tartrate-resistant acid phosphatase (TRAP) staining, F-actin staining, and a bone resorption pit assay were applied for identifying the effects of GLA on the differentiation of osteoclasts and the function of bone resorption. The mRNA expression of the genes related to osteoclast differentiation was measured by quantitative PCR. Protein expression of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), c-fos and phosphorylation of inhibitor of nuclear factor kappa B (IκBα), protein kinase B (AKT), c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 in RANKL-induced osteoclasts was determined using western blotting. The effect of GLA on OP was studied using a mouse model of OVX.

RESULTS

At nontoxic concentrations ≤0.5 μM in vitro, GLA suppressed the formation of osteoclasts induced by RANKL with the decreased number and area size of TRAP-positive multinuclear osteoclasts, and the resorption of bone function by reducing F-actin ring number and bone resorption pit areas. It also reduced the expression of the genes specific for osteoclasts, which included genes encoding NFATc1, cathepsin K, c-fos, TRAP, vacuolar-type ATPase d2, and dendritic cell-specific transmembrane protein. Moreover, GLA repressed NF-κB and Akt pathway activation induced by RANKL. Micro-CT analysis of femur samples indicated decreased bone loss and greater trabecular bone density after GLA treatment, which showed that GLA played a protective role by inhibiting bone loss in OVX-induced OP mice in vivo.

CONCLUSIONS

Our study is the first to show that GLA has significant therapeutic potential in OP, which is the disease of osteoclast increase caused by estrogen deficiency.

Pretreatment with Coenzyme Q10 Combined with Aescin Protects against Sepsis-Induced Acute Lung Injury

Sepsis-associated acute lung injury (ALI) is a critical condition characterized by severe inflammatory response and mitochondrial dysfunction. Coenzyme Q10 (CoQ10) and aescin (AES) are well-known for their anti-inflammatory activities. However, their effects on lipopolysaccharide (LPS)-induced lung injury have not been explored yet. Here, we asked whether combined pretreatment with CoQ10 and AES synergistically prevents LPS-induced lung injury. Fifty male rats were randomized into 5 groups: (1) control; (2) LPS-treated, rats received a single i.p. injection of LPS (8 mg/kg); (3) CoQ10-pretreated, (4) AES-pretreated, or (5) combined-pretreated; animals received CoQ10 (100 mg/kg), AES (5 mg/kg), or both orally for 7 days before LPS injection. Combined CoQ10 and AES pretreatment significantly reduced lung injury markers; 52.42% reduction in serum C-reactive protein (CRP), 53.69% in alkaline phosphatase (ALKP) and 60.26% in lactate dehydrogenase (LDH) activities versus 44.58, 37.38, and 48.6% in CoQ10 and 33.81, 34.43, and 39.29% in AES-pretreated groups, respectively. Meanwhile, combination therapy significantly reduced interleukin (IL)-1β and tumor necrosis factor (TNF)-α expressions compared to monotherapy (p < 0.05). Additionally, combination therapy prevented LPS-induced histological and mitochondrial abnormalities greater than separate drugs. Western blotting indicated that combination therapy significantly suppressed nucleotide-binding oligomerization domain (NOD)-like receptors-3 (NLRP-3) inflammasome compared to separate drugs (p < 0.05). Further, combination therapy significantly decreased the expression of signaling cascades, p38 mitogen-activated protein kinases (p38 MAPK), nuclear factor kappa B (NF-κB)-p65, and extracellular-regulated kinases 1/2 (ERK1/2) versus monotherapy (p < 0.05). Interestingly, combined pretreatment significantly downregulated high mobility group box-1 (HMGB1) by 72.93%, and toll-like receptor 4 (TLR4) by -0.93-fold versus 61.92%, -0.83-fold in CoQ10 and 38.67%, -0.70-fold in AES pretreatment, respectively. Our results showed for the first time that the enhanced anti-inflammatory effect of combined CoQ10 and AES pretreatment prevented LPS-induced ALI via suppression of NLRP-3 inflammasome through regulation of HMGB1/TLR4 signaling pathway and mitochondrial stabilization.

The Role and Mechanism of Pyroptosis and Potential Therapeutic Targets in Sepsis: A Review

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Recently was been found that pyroptosis is a unique form of proinflammatory programmed death, that is different from apoptosis. A growing number of studies have investigated pyroptosis and its relationship with sepsis, including the mechanisms, role, and relevant targets of pyroptosis in sepsis. While moderate pyroptosis in sepsis can control pathogen infection, excessive pyroptosis can lead to a dysregulated host immune response and even organ dysfunction. This review provides an overview of the mechanisms and potential therapeutic targets underlying pyroptosis in sepsis identified in recent decades, looking forward to the future direction of treatment for sepsis.

Phytochemical inhibitors of the NLRP3 inflammasome for the treatment of inflammatory diseases

The NLRP3 inflammasome holds a crucial role in innate immune responses. Pathogen- and danger-associated molecular patterns may initiate inflammasome activation and following inflammatory cytokine release. The inflammasome formation and its-associated activity are involved in various pathological conditions such as cardiovascular, central nervous system, metabolic, renal, inflammatory and autoimmune diseases. Although the mechanism behind NLRP3-mediated disorders have not been entirely illuminated, many phytochemicals and medicinal plants have been described to prevent inflammatory disorders. In the present review, we mainly introduced phytochemicals inhibiting NLRP3 inflammasome in addition to NLRP3-mediated diseases. For this purpose, we performed a systematic literature search by screening PubMed, Scopus, and Google Scholar databases. By compiling the data of phytochemical inhibitors targeting NLRP3 inflammasome activation, a complex balance between inflammasome activation or inhibition with NLRP3 as central player was pointed out in NLRP3-driven pathological conditions. Phytochemicals represent potential therapeutic leads, enabling the generation of chemical derivatives with improved pharmacological features to treat NLRP3-mediated inflammatory diseases.

Glaucocalyxin A suppresses inflammatory responses and induces apoptosis in TNF-a-induced human rheumatoid arthritis via modulation of the STAT3 pathway

The pathogenesis of rheumatoid arthritis (RA) is characterized by synoviocyte hyperplasia and proinflammatory cytokine secretion, as well as the destruction of cartilage and bone. Glaucocalyxin A (GLA) is an alkaloid derived from a Chinese medicinal plant that exhibits anti-inflammatory, anti-tumor and neuroprotective properties. We investigated the effects of GLA on RA-fibroblast-like synoviocytes (FLS cells), and collagen-induced arthritis (CIA), and further explored the underlying mechanisms. GLA inhibited TNF-a-induced RA-FLS proliferation, increased apoptotic ratios and upregulated levels of caspase-3, cleaved PARP, and Bax. GLA also inhibited the expression of IL-10, IL-1β, and IL-6 in vitro. Levels of p-STAT3 were downregulated in a dose-dependent manner. Over-expression of STAT3 partly neutralized the GLA-mediated elevation of caspase-3 and cleaved PARP levels as well as the downregulation of IL-10, IL-1B and IL-6 expression levels. This suggests that GLA inactivated the STAT3 pathway. Furthermore, the production of inflammatory cytokines in RA-FLS and a CIA rat model were inhibited effectively by GLA. Taken together, our data suggest that GLA is a potential long-term therapeutic agent for patients with RA.

Tranilast: a potential anti-Inflammatory and NLRP3 inflammasome inhibitor drug for COVID-19

SARS-CoV-2 is a type of beta-CoV that develops acute pneumonia, which is an inflammatory condition. A cytokine storm has been recognized as one of the leading causes of death in patients with COVID-19. ALI and ARDS along with multiple organ failure have also been presented as the consequences of acute inflammation and cytokine storm. It has been previously confirmed that SARS-CoV, as another member of the beta-CoV family, activates NLRP3 inflammasome and consequently develops acute inflammation in a variety of ways through having complex interactions with the host immune system using structural and nonstructural proteins. Numerous studies conducted on Tranilast have further demonstrated that the given drug can act as an effective anti-chemotactic factor on controlling inflammation, and thus, it can possibly help the improvement of the acute form of COVID-19 by inhibiting some key inflammation-associated transcription factors such as NF-κB and impeding NLRP3 inflammasome. Several studies have comparably revealed the direct effect of this drug on the prevention of inappropriate tissue's remodeling; inhibition of neutrophils, IL-5, and eosinophils; repression of inflammatory cell infiltration into inflammation site; restriction of factors involved in acute airway inflammation like IL-33; and suppression of cytokine IL-13, which increase mucosal secretions. Therefore, Tranilast may be considered as a potential treatment for patients with the acute form of COVID-19 along with other drugs.

Brevilin A inhibits NLRP3 inflammasome activation in vivo and in vitro by acting on the upstream of NLRP3-induced ASC oligomerization

Brevilin A (BA), is a natural biologically active ingredient derived from Centipeda minima with several reports of anti-cancer, while its anti-inflammatory activity is rarely reported. Current studies have found the dysregulated activation of NLRP3 inflammasome cause a variety of inflammatory diseases. Targeting the NLRP3 inflammasome contributes to the treatment of NLRP3-induced diseases. Here, we found that BA significantly attenuates the activation of caspase-1 and the subsequent secretion of the interleukin-1β (IL-1β) in mouse macrophages and human THP-1 cells, showing the inhibitory effect of BA on the NLRP3 inflammasome activation. Moreover, BA specifically inhibits NLRs inflammasomes activation triggered by multi-stimuli, but it has no effect on the AIM2 inflammasome activation, indicating that BA is a specific inhibitor of the NLRs inflammasomes. Research on the mechanism found BA inhibits NLRP3 inflammasome activation by blocking the upstream of ASC oligomerization. Importantly, in vivo experiments showed that BA markedly reduces the secretion of IL-1β to suppress NLRP3 inflammasome in the LPS-induced inflammation and MSU-challenged peritonitis model. In conclusion, our experiments show that BA is an effective NLRP3 inflammasome inhibitor and can be regarded as a drug candidate for NLRP3 inflammasome-driven diseases.

Glaucocalyxin A induces cell cycle arrest and apoptosis via inhibiting NF-κB/p65 signaling pathway in melanoma cells

AIMS

Melanoma is a malignant tumor of the skin with a high metastasis rate and poor prognosis. Glaucocalyxin A (GLA), isolated from Rabdosia japonica, is a diterpenoid compound with anticancer properties. Here, we investigated the anticancer properties and explored the mechanisms underlying GLA activity in melanoma cells in vitro and in vivo.

MAIN METHODS

Cell Counting Kit-8 and colony formation assays were used to assess the effects of GLA on cell proliferation. Flow cytometry was used to evaluate the cell cycle, apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS), and western blot analysis and immunofluorescence staining were used to examine protein expression. Immunohistochemical analysis was performed to examine animal tissues and tumors in mice.

KEY FINDINGS

GLA could effectively inhibit cell proliferation and induce cell apoptosis. GLA induced an overproduction of cellular ROS, decreased MMP, and upregulated the Bax/Bcl-2 ratio, which is an indicator of apoptosis. Phosphorylation of nuclear factor κB (NF-κB)/p65 and NF-κB/p65 nuclear expression decreased after GLA treatment in vitro and in vivo, suggesting that the anticancer effects of GLA are mediated through the NF-κB/p65 pathway. Moreover, we observed that GLA was effective in inhibiting tumor growth without obvious toxicity to major organs in mice.

SIGNIFICANCE

This is the first study to show that GLA inhibits cell proliferation, arrests the cell cycle in the G2/M phase, and induces mitochondrial apoptosis via the NF-κB/p65 pathway in melanoma cells. Overall, our results demonstrate that GLA may be a potential anticancer agent for the treatment of melanoma.