Development of a rectally administrable Dnase1 to treat septic shock by targeting NETs.

AIMS: Neutrophil extracellular trap (NET), which is formed by DNA threads, induces septic shock by aggravating systemic inflammation. An intravenous administration of deoxyribonuclease is regarded as a compelling modality for treating septic shock. However, alternative routes should be chosen when cutaneous veins are all collapsed due to hypotension. In this study, we genetically engineered this enzyme to develop a rectal suppository formulation to treat septic shock. MAIN METHODS: Dnase1 was mutated at two amino acid residues to increase its stability in the blood and fused with a cell-penetrating peptide CR8 to increase its absorption through the rectal mucosa, which is designated AR-CR8. The life-saving effect of AR-CR8 was evaluated in a LPS-induced shock mouse model. KEY FINDINGS: AR-CR8 was shown to remove NETs effectively in human neutrophils. When AR-CR8 was administered to the mouse rectum, the deoxyribonuclease activity in the mouse serum was significantly increased. In the LPS-induced shock model, 90 % of the control mice died over 72 h after LPS injection. In contrast, the rectal administration of AR-CR8 showed a mortality rate of 30 % by 72 h after LPS injection. The Log-rank test revealed that the survival rate is significantly higher in the AR-CR8 group. The NET markers in the mouse serum were enhanced by LPS, and significantly downregulated in the AR-CR8 group. These results suggest that AR-CR8 ameliorates LPS-induced shock by degrading NETs. SIGNIFICANCE: The engineered DNASE1 could be developed as a rectal suppository formulation to treat septic shock urgently at out-of-hospital places where no syringe is available.

The polyol pathway and nuclear ketohexokinase A signaling drive hyperglycemia-induced metastasis of gastric cancer.

Diabetes might be associated with increased cancer risk, with several studies reporting hyperglycemia as a primary oncogenic stimulant. Since glucose metabolism is linked to numerous metabolic pathways, it is difficult to specify the mechanisms underlying hyperglycemia-induced cancer progression. Here, we focused on the polyol pathway, which is dramatically activated under hyperglycemia and causes diabetic complications. We investigated whether polyol pathway-derived fructose facilitates hyperglycemia-induced gastric cancer metastasis. We performed bioinformatics analysis of gastric cancer datasets and immunohistochemical analyses of gastric cancer specimens, followed by transcriptomic and proteomic analyses to evaluate phenotypic changes in gastric cancer cells. Consequently, we found a clinical association between the polyol pathway and gastric cancer progression. In gastric cancer cell lines, hyperglycemia enhanced cell migration and invasion, cytoskeletal rearrangement, and epithelial-mesenchymal transition (EMT). The hyperglycemia-induced acquisition of metastatic potential was mediated by increased fructose derived from the polyol pathway, which stimulated the nuclear ketohexokinase-A (KHK-A) signaling pathway, thereby inducing EMT by repressing the CDH1 gene. In two different xenograft models of cancer metastasis, gastric cancers overexpressing AKR1B1 were found to be highly metastatic in diabetic mice, but these effects of AKR1B1 were attenuated by KHK-A knockdown. In conclusion, hyperglycemia induces fructose formation through the polyol pathway, which in turn stimulates the KHK-A signaling pathway, driving gastric cancer metastasis by inducing EMT. Thus, the polyol and KHK-A signaling pathways could be potential therapeutic targets to decrease the metastatic risk in gastric cancer patients with diabetes.

Tumor regionalization after surgery: Roles of the tumor microenvironment and neutrophil extracellular traps.

Surgery is unanimously regarded as the primary strategy to cure solid tumors in the early stages but is not always used in advanced cases. However, tumor surgery must be carefully considered because the risk of metastasis could be increased by the surgical procedure. Tumor surgery may result in a deep wound, which induces many biological responses favoring tumor metastasis. In particular, NETosis, which is the process of forming neutrophil extracellular traps (NETs), has received attention as a risk factor for surgery-induced metastasis. To reduce cancer mortality, researchers have made efforts to prevent secondary metastasis after resection of the primary tumor. From this point of view, a better understanding of surgery-induced metastasis might provide new strategies for more effective and safer surgical approaches. In this paper, recent insights into the surgical effects on metastasis will be reviewed. Moreover, in-depth opinions about the effects of NETs on metastasis will be discussed.

Artemisia Extract Suppresses NLRP3 and AIM2 Inflammasome Activation by Inhibition of ASC Phosphorylation.

Artemisia princeps var. orientalis (Asteraceae, A. princeps) is a well-known traditional medicinal herb used for treating various inflammatory disorders in Korea, Japan, China, and other Asian countries. In the present study, we investigated the effects of A. princeps extract (APO) on interleukin- (IL-) 1ß regulation and inflammasome activation in bone marrow-derived macrophages (BMDMs) and monosodium urate- (MSU-) induced peritonitis mouse model in vivo. The APO treatment to BMDMs primed with lipopolysaccharide (LPS) attenuated the NLRP3 and AIM2 inflammasome activation induced by danger signals, such as ATP, nigericin, silica crystals, and poly (dA:dT), respectively. Mechanistic study revealed that APO suppressed the ASC oligomerization and speck formation, which are required for inflammasome activation. APO treatment also reduced the ASC phosphorylation induced by the combination of LPS and a tyrosine phosphatase inhibitor. In vivo evaluation revealed that intraperitoneal administration of APO reduced IL-1ß levels, significantly (p < 0.05) and dose dependently, in the MSU-induced peritonitis mouse model. In conclusion, our study is the first to report that the extract of A. princeps inhibits inflammasome activation through the modulation of ASC phosphorylation. Therefore, APO might be developed as therapeutic potential in the treatment of inflammasome-mediated inflammatory disorders, such as gouty arthritis.

Inhibitory Effect and Mechanism of Arctium lappa Extract on NLRP3 Inflammasome Activation.

Arctium lappa (A. lappa), Compositae, is considered a potential source of nutrition and is used as a traditional medicine in East Asian countries for centuries. Although several studies have shown its biological activities as an anti-inflammatory agent, there have been no reports on A. lappa with regard to regulatory role in inflammasome activation. The purpose of this study was to investigate the inhibitory effects of A. lappa extract (ALE) on NLRP3 inflammasome activation and explore the underlying mechanisms. We found that ALE inhibited IL-1ß secretion from NLRP3 inflammasome activated bone marrow derived macrophages but not that secreted by NLRC4 and AIM2 inflammasomes activation. Mechanistic studies revealed that ALE suppressed the ATPase activity of purified NLRP3 and reduced mitochondrial reactive oxygen species (mROS) generated during NLRP3 activation. Therefore, the inhibitory effect of ALE on NLRP3 inflammasome might be attributed to its ability to inhibit the NLRP3 ATPase function and attenuated the mROS during inflammasome activation. In addition, ALE significantly reduced the LPS-induced increase of plasma IL-1ß in mouse peritonitis model. These results provide evidence of novel anti-inflammatory mechanisms of A. lappa, which might be used for therapeutic applications in the treatment of NLRP3 inflammasome-associated inflammatory disorders.

Anti-inflammatory properties of Morus bombycis Koidzumi via inhibiting IFN-ß signaling and NLRP3 inflammasome activation.

ETHNOPHARMACOLOGICAL RELEVANCE: Morus bombycis Koidzumi (M. bombycis, Moraceae) has been used in Asian countries as a traditional medicine for the treatment of hypertension, diabetes, and inflammation-related disorders. AIM OF STUDY: Although its anti-inflammatory actions have been partly documented, scientific evidence involving its molecular mechanisms related to inflammasome activation signaling pathways remains unknown. MATERIALS AND METHODS: Lipopolysaccharide-stimulated RAW 264.7 cells and bone marrow-derived murine macrophages were used to study the in vitro effect of methanolic extract of M. bombycis (MB) on inflammatory responses. A monosodium urate crystal (MSU)-induced peritonitis murine model was used to study the in vivo effects. RESULTS: MB attenuated the production of nitric oxide and interleukin-6, through the regulation of the interferon-ß receptor signaling pathway. MB also inhibited IL-1ß secretion via attenuation of NLRP3 inflammasome activation. Furthermore, MB inhibited MSU-induced peritonitis in the in vivo murine model. CONCLUSIONS: This study provides the key molecular mechanisms involved in the anti-inflammatory effects of M. bombycis, substantiating the traditional claims of its use in the treatment of inflammation-related disorders.

Anti-inflammatory effect of emodin via attenuation of NLRP3 inflammasome activation.

Emodin, an active constituent of oriental herbs, is widely used to treat allergy, inflammation, and other symptoms. This study provides the scientific basis for the anti-inflammasome effects of emodin on both in vitro and in vivo experimental models. Bone marrow-derived macrophages were used to study the effects of emodin on inflammasome activation by using inflammasome inducers such as ATP, nigericin, and silica crystals. The lipopolysaccharide (LPS)-induced endotoxin shock model was employed to study the effect of emodin on in vivo efficacy. Emodin treatment attenuated interleukin (IL)-1ß secretion via the inhibition of NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation induced by ATP, nigericin, and silica crystals. Further, emodin ameliorated the severity of NLRP3 inflammasome-mediated symptoms in LPS-induced endotoxin mouse models. This study is the first to reveal mechanism-based evidence, especially with respect to regulation of inflammasome activation, substantiating traditional claims of emodin in the treatment of inflammation-related disorders.

Syneilesis palmata (Thunb.) Maxim. extract attenuates inflammatory responses via the regulation of TRIF-dependent signaling and inflammasome activation.

ETHNOPHARMACOLOGICAL RELEVANCE: Syneilesis palmata (Thunb.) Maxim. (S. palmata, Asteraceae) is a traditional Korean therapeutic herb widely used to treat pain, arthritis, and other symptoms. This study provides the scientific basis for the anti-inflammatory effects of S. palmata extract (SP) in both in vitro and in vivo experimental models. MATERIALS AND METHODS: Lipopolysaccharide (LPS)-stimulated murine macrophages were used to study the regulatory effect of SP on the inflammatory mediators in vitro. Bone marrow-derived macrophages were used to study the effects of SP on inflammasome activation. Escherichia coli-induced sepsis mouse model and LPS-induced endotoxin shock model were employed to study the effect of SP on in vivo efficacy. RESULTS: SP inhibited the LPS-stimulated release of proinflammatory mediators, such as nitric oxide and interleukin (IL)-6 in RAW 264.7 cells. SP treatment also attenuated IL-1ß secretion via the inhibition of NLRP3 inflammasome activation induced by monosodium urate, ATP, and nigericin. Further, SP ameliorated the severity of NLRP3 inflammasome-mediated symptoms in LPS-induced endotoxin and E. coli-induced sepsis mouse models. Mechanistic studies revealed that inhibitory effects of SP were mediated through the regulation of TRIF-dependent signaling and inflammasome activation. CONCLUSION: This study was the first to reveal mechanistic-based evidence substantiating the traditional claims of SP in the treatment of inflammation-related disorders, such as pain and arthritis.