Chemokines and Chemokine Receptors in the Development of NAFLD

Roh, Yoon-Seok,Seki, Ekihiro Kluwer Academic Publishers 2018 Advances in experimental medicine and biology Vol.1061 No.-

Neurotropin Treatment Can Lead to Autophagy in Liver by AMPK Phosphorylation

( Jeong Han Kim ),( Yoon Mee Yang ),( Ekihiro Seki ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: Autophagy has two main function: to eliminate potentially hazardous or dysfunctional organelles or proteins, and to obtain energy and new building blocks for protein synthesis. Neurotropin is a drug derived from a non-protein fraction extracted from the inflamed skin of rabbits after the administration of vaccina virus. We aimed to investigate whether neurotropin can induce autophagy in liver. Methods: We treated HepG2 cell line with neurotropin 0.2 NU/ ml and 0.4 NU/ml. As a positive control metformin 2mM was used. Samples were collected at baseline, 3 hours, 6 hours, 9 hours and overnight after treatment. Western blot was performed with Phospho-AMPK(p-AMPK), AMPK, LC3B and SQSTM1(p62) monoclonal antibodies as primary antibody. Results: Western blot showed enhanced expression of p-AMPK and LC3B II protein after neurotropin treatment. AMPK and p62 expressions were not different from baseline. Conclusions: Neurotropin treatment has possibility to induce autophagy in liver disease by AMPK phosphorylation. Further investigation including in vivo experiment is warranted.

The nicotinamide adenine dinucleotide phosphate oxidase (NOX) homologues NOX1 and NOX2/gp91^phox mediate hepatic fibrosis in mice

Paik, Yong‐,Han,Iwaisako, Keiko,Seki, Ekihiro,Inokuchi, Sayaka,Schnabl, Bernd,Ö,sterreicher, Christoph H.,Kisseleva, Tatiana,Brenner, David A. Wiley Subscription Services, Inc., A Wiley Company 2011 Hepatology Vol.53 No.5

<P><B>Abstract</B></P><P>Nicotinamide adenine dinucleotide phosphate oxidase (NOX) is a multicomponent enzyme that mediates electron transfer from nicotinamide adenine dinucleotide phosphate to molecular oxygen, which leads to the production of superoxide. NOX2/gp91<SUP>phox</SUP> is a catalytic subunit of NOX expressed in phagocytic cells. Several homologues of NOX2, including NOX1, have been identified in nonphagocytic cells. We investigated the contributory role of NOX1 and NOX2 in hepatic fibrosis. Hepatic fibrosis was induced in wild‐type (WT) mice, NOX1 knockout (NOX1KO) mice, and NOX2 knockout (NOX2KO) mice by way of either carbon tetrachloride (CCl<SUB>4</SUB>) injection or bile duct ligation (BDL). The functional contribution of NOX1 and NOX2 in endogenous liver cells, including hepatic stellate cells (HSCs), and bone marrow (BM)‐derived cells, including Kupffer cells (KCs), to hepatic reactive oxygen species (ROS) generation and hepatic fibrosis was assessed <I>in vitro</I> and <I>in vivo</I> using NOX1 or NOX2 BM chimeric mice. Hepatic NOX1 and NOX2 messenger RNA expression was increased in the two experimental mouse models of hepatic fibrosis. Whereas NOX1 was expressed in HSCs but not in KCs, NOX2 was expressed in both HSCs and KCs. Hepatic fibrosis and ROS generation were attenuated in both NOX1KO and NOX2KO mice after CCl<SUB>4</SUB> or BDL. Liver fibrosis in chimeric mice indicated that NOX1 mediates the profibrogenic effects in endogenous liver cells, whereas NOX2 mediates the profibrogenic effects in both endogenous liver cells and BM‐derived cells. Multiple NOX1 and NOX2 components were up‐regulated in activated HSCs. Both NOX1‐ and NOX2‐deficient HSCs had decreased ROS generation and failed to up‐regulate collagen α1(I) and transforming growth factor β in response to angiotensin II. <I>Conclusion:</I> Both NOX1 and NOX2 have an important role in hepatic fibrosis in endogenous liver cells, including HSCs, whereas NOX2 has a lesser role in BM‐derived cells. (H<SMALL>EPATOLOGY</SMALL> 2011;)</P>

Inhibition of hyaluronan synthesis by 4-methylumbelliferone ameliorates non-alcoholic steatohepatitis in choline-deficient L -amino acid-defined diet-induced murine model

Yoon Mee Yang,Zhijun Wang,Michitaka Matsuda,Ekihiro Seki 대한약학회 2021 Archives of Pharmacal Research Vol.44 No.2

Hyaluronan (HA) as a glycosaminoglycan canbind to cell-surface receptors, such as TLR4, to regulateinfl ammation, tissue injury, repair, and fi brosis. 4-methylumbelliferone(4-MU), an inhibitor of HA synthesis, is adrug used for the treatment of biliary spasms. Currently,therapeutic interventions are not available for non-alcoholicsteatohepatitis (NASH). In this study, we investigated theeff ects of 4-MU on NASH using a choline-defi cient aminoacid (CDAA) diet model. CDAA diet-fed mice showedNASH characteristics, including hepatocyte injury, hepaticsteatosis, infl ammation, and fi brogenesis. 4-MU treatmentsignifi cantly reduced hepatic lipid contents in CDAA dietfedmice. 4-MU reversed CDAA diet-mediated inhibitionof Ppara and induction of Srebf1 and Slc27a2 . Analysis ofserum ALT and AST levels revealed that 4-MU treatmentprotected against hepatocellular damage induced by CDAAdiet feeding. TLR4 regulates low molecular weight-HAinducedchemokine expression in hepatocytes. In CDAAdiet-fed, 4-MU-treated mice, the upregulated chemokine/cytokine expression, such as Cxcl1 , Cxcl2 , and Tnf wasattenuated with the decrease of macrophage infi ltration intothe liver. Moreover, HA inhibition repressed CDAA dietinducedmRNA expression of fi brogenic genes, Notch1 , and Hes1 in the liver. In conclusion, 4-MU treatment inhibitedliver steatosis and steatohepatitis in a mouse model ofNASH, implicating that 4-MU may have therapeutic potentialfor NASH.

Hyaluronan synthase 2, a target of miR-200c, promotes carbon tetrachloride-induced acute and chronic liver inflammation via regulation of CCL3 and CCL4

김선명,송가연,Shim Aeri,Lee Jee Hyung,엄철빈,Liu Cheng,양윤미,Seki Ekihiro 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Liver fibrosis occurs during wound healing after repeated liver injury and is characterized by extensive extracellular matrix deposition. We previously identified hyaluronan synthase 2 (HAS2) as a driver of liver fibrosis and hepatic stellate cell (HSC) activation. Developing strategies to suppress HSC activation is key to alleviating liver fibrosis, and HAS2 is an attractive candidate for intervention. To gain insight into the molecular function of HAS2, we investigated its posttranscriptional regulation. We found that miR-200c directly targets the 3’ untranslated regions of HAS2. Moreover, miR-200c and HAS2 were inversely expressed in fibrotic human and mouse livers. After establishing the direct interaction between miR-200c and HAS2, we investigated the functional outcome of regulating HAS2 expression in three murine models: CCl4-induced acute liver injury, CCl4-induced chronic liver fibrosis, and bile duct ligation-induced liver fibrosis. Hepatic Has2 expression was induced by acute and chronic CCl4 treatment. In contrast, miR-200c expression was decreased after CCl4 treatment. HSC-specific Has2 deletion reduced the expression of inflammatory markers and infiltration of macrophages in the models. Importantly, hyaluronidase-2 (HYAL2) but not HYAL1 was overexpressed in fibrotic human and murine livers. HYAL2 is an enzyme that can cleave the extracellular matrix component hyaluronan. We found that low-molecular-weight hyaluronan stimulated the expression of inflammatory genes. Treatment with the HA synthesis inhibitor 4-methylumbelliferone alleviated bile duct ligation-induced expression of these inflammatory markers. Collectively, our results suggest that HAS2 is negatively regulated by miR-200c and contributes to the development of acute liver injury and chronic liver inflammation via hyaluronan-mediated immune signaling.

The expression of KAP3K7 regulates the susceptibility to steatosis-associated liver injury and fibrosis

Yeojin Lee,Jeong-Su Park,Feng Wang,Hwan Ma,Ekihiro Seki,Hwan-Soo Yoo,Yoon-Seok Roh 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease, and its significant risk of steatohepatitis and liver fibrosis can result in cirrhosis and liver cancer. TAK1 (MAP3K7) is a MAP3K of TLRs, IL-1, TNF and TGF-β receptor signaling. In a previous study, we have been reported MAP3K7 protects against hepatocyte death, inflammation and fibrosis. Currently, we studied the mechanism how MAP3K7 affects on steatosis-associated liver fibrosis. Interestingly we found that liver of HFD+CCl4-treated mice have significantly decreased expression of MAP3K7 compared with those of LFD+CCl4 treated mice. These results are consistent with data showing reduced expression of MAP3K7 in (Ob / Ob) mice, indicating that lipid accumulation reduces MAP3K7 expression. Based on these data, we hypothesized that genetic deletion of MAP3K7 can mimic the phenotypes of HFD-induced MAP3K7 reduction. As we expected, hepatocyte-specific MAP3K7-deficient mice induced more severe CCl4-induced fibrosis than WT mice. In addition, we found that MAP3K7- defciency induces various pathologies vulnerable to autophagy defects, aberrant mTORC1 activation, Smad2 / 3 activation, cytokine-induced stem cell death, and PPAR-α suppression. Therefore, reduction of MAP3K7 in advanced fatty liver disease increases the susceptibility to toxin-induced hepatocellular toxicity, liver inflammation, and fibrosis.

IL6ST regulates liver tumorigenesis via the regulation of mitophagy

Hwan Ma,Jeong-Su Park,Feng Wang,Yeo-Jin Lee,Gyu-Rim Lee,Ekihiro Seki,Hwan-Soo Yoo,Yoon-Seok Roh 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7

Hepatocellular carcinoma (HCC) is the sixth most commonly occurring cancer in the world and the third largest cause of cancer mortality. There is increasing evidence that the inflammatory process is inherently associated with many different cancer types, including HCC. Cytokines are released in response to a diverse range of cellular stresses, including carcinogen-induced injury, infection, and inflammation. A number of cytokines that are produced in the tumor microenvironment have an important role in cancer pathogenesis. Among them, there are IL-6 family cytokines that share the common receptor subunit IL6ST. IL6ST regulates cell survival, growth, and proliferation through the regulation of JAK-Stat3 and PI3K-mTORC1. Both downstream pathways have been linked with autophagy and mitochondrial function. Moreover, mitophagy contributes to metabolic dysfunction syndrome and chronic liver diseases such as NAFLD, NASH, and HCC. However, the mechanism of how IL6ST modulates hepatocyte mitophagy and HCC development remains unclear. IL6ST activated Stat3 and mTORC1 signaling in HCC, as evidenced by the controls phosphorylation of Stat3 (Tyr705), P70S6K(T389), EIF4E(S209), and RPS6(S235). Interestingly, IL6ST prevents mitochondrial stress and improves cell viability by inhibition of Stat3 and mTORC1-ULK1 mediated mitophagy and apoptosis. In genetically engineered mouse models of HCC (TAK1ΔHep), hepatocyte-specific deletion of IL6ST suppressed the multiplicity and maximum size of naturally occurring cancer. In conclusion, IL6ST governs parallel activation of carcinogenic STAT3 along with mTORC1 in the pathogenesis of HCC by regulation of mitophagy-dependent apoptosis and cancer cell survival.

Gα12 ablation exacerbates liver steatosis and obesity by suppressing USP22/SIRT1-regulated mitochondrial respiration

Kim, Tae Hyun,Yang, Yoon Mee,Han, Chang Yeob,Koo, Ja Hyun,Oh, Hyunhee,Kim, Su Sung,You, Byoung Hoon,Choi, Young Hee,Park, Tae-Sik,Lee, Chang Ho,Kurose, Hitoshi,Noureddin, Mazen,Seki, Ekihiro,Wan, Yu-J American Society for Clinical Investigation 2018 The Journal of clinical investigation Vol.128 No.12