Jeeyoung Kim

Dimethyl sulfoxide inhibits NLRP3 inflammasome activation

Dimethyl sulfoxide (DMSO) is an amphipathic molecule that is commonly/widely used as a solvent for biological compounds. In addition, DMSO has been studied as a medication for the treatment of inflammation, cystitis, and arthritis. Based on the anti-inflammatory characteristics of DMSO, we elucidated the effects of DMSO on activation of inflammasomes, which are cytoplasmic multi-protein complexes that mediate the maturation of interleukin (IL)-1β by activating caspase-1 (Casp1). In the present study, we prove that DMSO attenuated IL-1β maturation, Casp1 activity, and ASC pyroptosome formation via NLRP3 inflammasome activators. Further, NLRC4 and AIM2 inflammasome activity were not affected, suggesting that DMSO is a selective inhibitor of the NLRP3 inflammasomes. The anti-inflammatory effect of DMSO was further confirmed in animal, LPS-endotoxin sepsis and inflammatory bowel disease models. In addition, DMSO inhibited LPS-mediating IL-1s transcription. Taken together, DMSO shows anti-inflammatory characteristics, attenuates NLRP3 inflammasome activation, and mediates inhibition of IL-1s transcription.

Korean red ginseng extracts inhibit NLRP3 and AIM2 inflammasome activation

Korean red ginseng extract (RGE) is one of the most popular natural herbs modulating the immune system. Although the effects of RGE on immunity have been reported, its effects on inflammasomes, multi-protein complexes that activate caspase-1 to induce maturation of interleukin (IL)-1β, have not been studied yet. In this study, we elucidated the effect of RGE on inflammasome activation using mouse and human macrophages. In our results, RGE inhibited IL-1β maturation resulting from NLRP3 inflammasome activation in both in vitro and in vivo models. In addition, RGE strongly attenuated IL-1β secretion as well as pathogen clearance via pyroptotic cell death by macrophages through inhibition of AIM2 inflammasome activation. Ginsenosides Rg1 and Rh3 were suggested as inhibitors of the inflammasome activation. Thus, we demonstrated that RGE inhibits both NLRP3 and AIM2 inflammasome activation, with predominant involvement of the AIM2 inflammasome.

Methylsulfonylmethane inhibits NLRP3 inflammasome activation

Methylsulfonylmethane (MSM) is an organosulfur compound and the health benefits associated with MSM include inflammation. Although MSM has been shown to have various physiological effects, no study has yet focused on inflammasome activation. The inflammasome is a multiprotein complex that serves as a platform for caspase 1-dependent proteolytic maturation and secretion of interleukin-1β (IL-1β). In this study, we tested the effect of MSM on inflammasome activation using mouse and human macrophages. In our results, MSM significantly attenuated NLRP3 inflammasome activation in lipopolysaccharide-primed macrophages, although it had no effect on NLCR4 or AIM2 inflammasome activation. Extracts of MSM-enriched vegetables presented the same inhibitory effect on NLRP3 inflammasome activation as MSM. MSM also attenuated the transcriptional expression of IL-1α, IL-1β, IL-6, and NLRP3. Taken together, these results show that MSM has anti-inflammatory characteristics, interrupts NLRP3 inflammasome activation, and inhibits pro-cytokine expression. We further confirmed the intracellular mechanism of MSM in relation to NLRP3 inflammasome activation, followed by comparison with that of DMSO. Both chemicals showed a synergic effect on anti-NLRP3 activation and attenuated production of mitochondrial reactive oxygen species (ROS). Thus, MSM is a selective inhibitor of NLRP3 inflammasome activation and can be developed as a supplement to control several metabolic disorders.

Characterization of porcine NLRP3 inflammasome activation and its upstream mechanism

Inflammasomes, which are intracellular sensors of endogenous or exogenous danger signals, activate caspase-1, resulting in interleukin (IL)-1β maturation. Although most studies on inflammasomes have been performed in human and/or mouse-derived macrophages, porcine inflammasome activation has not been elucidated even though pigs are considered one of the best animal models for translational and preclinical investigations. In this study, we optimized detection of porcine IL-1β secretion, which is the most well established indicator of inflammasome activation, and compared inflammasome activation between miniature and domestic pigs as well as between porcine and murine macrophages. In our results, anti-sera against murine IL-1β had higher affinity to porcine IL-1β than anti-sera against human IL-1β, even though the amino acid sequence of porcine IL-1β was more similar to that of human IL-1β. In addition, there was no significant difference in inflammasome activation between miniature and domestic pigs. Furthermore, well established inflammasome triggers (ATP, nigericin, and crystals) in humans and mice had similar effects on porcine NLRP3 inflammasome activation. We further elucidated the upstream signaling pathway of porcine inflammasome activation using pharmacological inhibitors. Similar to the mechanisms of inflammasome activation in humans and mice, potassium efflux and reactive oxygen species generation were confirmed as key pathways in porcine inflammasome activation. Thus, inflammasome activation in pigs is not different from that in humans or mice.

Cadmium-induced ER stress and inflammation are mediated through C/EBP–DDIT3 signaling in human bronchial epithelial cells

Cadmium (Cd), a major component of cigarette smoke, disrupts the normal functions of airway cells and can lead to the development of various pulmonary diseases such as chronic obstructive pulmonary disease (COPD). However, the molecular mechanisms involved in Cd-induced pulmonary diseases are poorly understood. Here, we identified a cluster of genes that are altered in response to Cd exposure in human bronchial epithelial cells (BEAS-2B) and demonstrated that Cd-induced ER stress and inflammation are mediated via CCAAT-enhancer-binding proteins (C/EBP)-DNA-damaged-inducible transcript 3 (DDIT3) signaling in BEAS-2B cells. Cd treatment led to marked upregulation and downregulation of genes associated with the cell cycle, apoptosis, oxidative stress and inflammation as well as various signal transduction pathways. Gene set enrichment analysis revealed that Cd treatment stimulated the C/EBP signaling pathway and induced transcriptional activation of its downstream target genes, including DDIT3. Suppression of DDIT3 expression using specific small interfering RNA effectively alleviated Cd-induced ER stress and inflammatory responses in both BEAS-2B and normal primary normal human bronchial epithelial cells. Taken together, these data suggest that C/EBP signaling may have a pivotal role in the early induction of ER stress and inflammatory responses by Cd exposure and could be a molecular target for Cd-induced pulmonary disease.

Generation of liver-specific TGF-α and c-Myc-overexpressing fibroblasts for future creation of a liver cancer porcine model.

Liver cancer is one of the most serious life-threatening diseases in the world. Although the rodent model of hepatocellar carcinoma (HCC) is commonly used, it is limited when considering preclinical applications, including transarterial chemoembolization. The pig is a more appropriate model for applying preclinical procedures as it has similar anatomical and physiological characteristics to humans. In the current study, transgenic fibroblasts were generated that overexpressed two proto-oncogenes specifically in hepatocytes. Porcine TGF-α and c-myc genes were isolated and these were linked with the porcine albumin promoter, which has exhibited selective activity in liver cells. Targeting vectors were introduced into the porcine fibroblasts using a liposome-mediated delivery system and the transgenic cell line was screened with 3 weeks of G-418 treatment. Selected vector‑positive colonies were further confirmed with polymerase chain reaction-based genotyping. Thus, the transgenic cell lines created in the current study should induce liver cancer in pig models following somatic cell nuclear transfer.

ACN9 Regulates the Inflammatory Responses in Human Bronchial Epithelial Cells

Background Airway epithelial cells are the first line of defense, against pathogens and environmental pollutants, in the lungs. Cellular stress by cadmium (Cd), resulting in airway inflammation, is assumed to be directly involved in tissue injury, linked to the development of lung cancer, and chronic obstructive pulmonary disease (COPD). We had earlier shown that ACN9 (chromosome 7q21), is a potential candidate gene for COPD, and identified significant interaction with smoking, based on genetic studies. However, the role of ACN9 in the inflammatory response, in the airway cells, has not yet been reported. Methods We first checked the anatomical distribution of ACN9 in lung tissues, using mRNA in situ hybridization, and immunohistochemistry. Gene expression profiling in bronchial epithelial cells (BEAS-2B), was performed, after silencing ACN9. We further tested the roles of ACN9, in the intracellular mechanism, leading to Cd-induced production, of proinflammatory cytokines in BEAS-2B. Results ACN9 was localized in lymphoid, and epithelial cells, of human lung tissues. ACN9 silencing, led to differential expression of 216 genes. Pathways of sensory perception to chemical stimuli, and cell surface receptor-linked signal transduction, were significantly enriched. ACN9 silencing, further increased the expression of proinflammatory cytokines, in BEAS-2B after Cd exposure. Conclusion Our findings suggest, that ACN9 may have a role, in the inflammatory response in the airway.