Dataset Information

An endoplasmic reticulum protein, Nogo-B, facilitates alcoholic liver disease through regulation of kupffer cell polarization.

ABSTRACT: Nogo-B (Reticulon 4B) is an endoplasmic reticulum (ER) resident protein that regulates ER structure and function. Because ER stress is known to induce M2 macrophage polarization, we examined whether Nogo-B regulates M1/M2 polarization of Kupffer cells and alters the pathogenesis of alcoholic liver disease (ALD). M1 and M2 phenotypes were assessed in relation to Nogo-B expression and disease severity in liver specimens from ALD patients (NCT01875211). Liver specimens from wild-type (WT) and Nogo-B knockout (KO) mice fed a control or Lieber-DeCarli ethanol liquid diet (5% ethanol) for 6 weeks were analyzed for liver injury and steatosis. Kupffer cells isolated from WT and Nogo-B KO mice were assessed for M1 and M2 activation. A significant positive correlation was observed between Nogo-B positive Kupffer cells and disease severity in ALD patients (n = 30, r = 0.66, P = 0.048). Furthermore, Nogo-B-positive Kupffer cells were correlated with M1 activation (inducible nitric oxide synthase) (r = 0.50, P = 0.05) and negatively with markers of M2 status (CD163) (r = -0.48, P = 0.07) in these patients. WT mice exhibited significantly increased liver injury (P < 0.05) and higher hepatic triglyceride levels (P < 0.01) compared with Nogo-B KO mice in response to chronic ethanol feeding. Nogo-B in Kupffer cells promoted M1 polarization, whereas absence of Nogo-B increased ER stress and M2 polarization in Kupffer cells.

Conclusion

Nogo-B is permissive of M1 polarization of Kupffer cells, thereby accentuating liver injury in ALD in humans and mice. Nogo-B in Kupffer cells may represent a new therapeutic target for ALD. (Hepatology 2017;65:1720-1734).

SUBMITTER: Park JK

PROVIDER: S-EPMC5397326 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

An endoplasmic reticulum protein, Nogo-B, facilitates alcoholic liver disease through regulation of kupffer cell polarization.

Park Jin-Kyu JK Shao Mingjie M Kim Moon Young MY Baik Soon Koo SK Cho Mee Yon MY Utsumi Teruo T Satoh Ayano A Ouyang Xinsho X Chung Chuhan C Iwakiri Yasuko Y

Hepatology (Baltimore, Md.) 20170322 5

Nogo-B (Reticulon 4B) is an endoplasmic reticulum (ER) resident protein that regulates ER structure and function. Because ER stress is known to induce M2 macrophage polarization, we examined whether Nogo-B regulates M1/M2 polarization of Kupffer cells and alters the pathogenesis of alcoholic liver disease (ALD). M1 and M2 phenotypes were assessed in relation to Nogo-B expression and disease severity in liver specimens from ALD patients (NCT01875211). Liver specimens from wild-type (WT) and Nogo- ...[more]

PMID: 28090670

Similar Datasets

Project description:Non-esterified fatty acids (NEFAs) promote de novo lipogenesis, which caused abnormal hepatic lipid accumulation, by the NF?B-Orai1 pathway. Oxidative stress and endoplasmic reticulum (ER) stress have been recognized as key mechanisms in non-alcoholic fatty liver disease (NAFLD) pathogenesis. Whether Orai1 facilitates ER stress by oxidative stress remains unknown. The rat model of NAFLD was constructed by feeding high-fat diet (HFD). BRL-3A cells were treated with NEFAs, Orai1inhibtor BTP2, NF?B inhibitor wogonin, or small interfering Orai (siOrai) 1, respectively. The content of intracellular reduced glutathione (GSH) and malondialdehyde (MDA), indicating oxidative stress, was measured by a spectrophotometer. ER stress major proteins PERK, IRE1, ATF6, CHOP, and GRP78 were quantified using Western blot and qRT-PCR analyses. For the intracellular location of reactive oxygen species (ROS) and Orai1 were measured by Western blot and immunofluorescence, and cytosolic Ca2+ was measured by flow cytometry. As we expected, the liver of rats with NAFLD showed lipid droplets in HE and Oil Red O. The decreased GSH and increased MDA were found in rats fed with HFD. ER stress major proteins PERK, IRE1, ATF6, GRP78, and CHOP were significantly increased in the HFD group. In BRL-3A cells, GSH content dramatically decreased from 1 h, MDA content dramatically increased from 3 h, and expression levels of ER stress significantly increased from 3 h by NEFA treatment. Furthermore, cytosolic Ca2+ increased from 0.5 h by NEFAs treated in BRL-3A cells. It indicated that NEFAs increased cytosolic Ca2+ to induce oxidative stress, thus ER stress. The content of oxidative stress and ER stress proteins showed the same trends by NEFAs treated in BRL-3A cells. These effects were reversed by the Orai1 inhibitor BTP2 and the NF?B inhibitor wogonin. Moreover, siOrai1 abrogated NEFAs' influence in BRL-3A cells. Last, ROS was found by NEFAs treated in BRL-3A cells, and NEFA treatment enhanced the nuclear localization of NF-?B p65 and ORAI1. It was considered that high NEFAs increased cytosolic Ca2+ and enhanced NF?B-dependent SOCE and its moiety protein Orai1 to decrease GSH and thus induced oxidative stress at earlier stages and furthermore tempted ER stress in the pathologic progress of NAFLD.

Project description:Cellular stress-mediated chaperones are linked to liver macrophage activation and inflammation in alcohol-associated liver disease (ALD). In this study, we investigate the role of endoplasmic reticulum (ER) resident stress chaperone GP96/HSP90B1/GRP94, paralog of the HSP90 family, in ALD pathogenesis. We hypothesize that ER resident chaperone, heat shock protein GP96, plays a crucial role in alcohol-associated liver inflammation and contributes to liver injury. We show high expression of GP96/HSP90B1 and GRP78/HSPA5 in human alcohol-associated hepatitis livers as well as in mouse ALD livers with induction of GP96 prominent in alcohol-exposed macrophages. Myeloid-specific GP96 deficient (M-GP96KO) mice failed to induce alcohol-associated liver injury. Alcohol-fed M-GP96KO mice exhibit significant reduction in steatosis, serum endotoxin, and pro-inflammatory cytokines compared with wild-type mice. Anti-inflammatory cytokines interleukin-10 and transforming growth factor β, as well as activating transcription factor 3 and triggering receptor expressed on myeloid cells 2, markers of restorative macrophages, were higher in alcohol-fed M-GP96KO livers. M-GP96KO mice exhibit protection in a model of endotoxin-mediated liver injury in vivo, which is in agreement with reduced inflammatory responses during ex vivo lipopolysaccharide/endotoxin- stimulated bone marrow-derived macrophages from M-GP96KO mice. Furthermore, we show that liver macrophages from alcohol-fed M-GP96KO mice show compensatory induction of GRP78 messenger RNA, likely due to increased splicing of X-box binding protein-1. Finally, we show that inhibition of GP96 using a specific pharmacological agent, PU-WS13 or small interfering RNA, alleviates inflammatory responses in primary macrophages. Conclusion: Myeloid ER resident GP96 promotes alcohol-induced liver damage through activation of liver macrophage inflammatory responses, alteration in lipid homeostasis, and ER stress. These findings highlight a critical role for liver macrophage ER resident chaperone GP96/HSP90B1 in ALD, and its targeted inhibition represents a promising therapeutic approach in ALD.

Dataset Information

An endoplasmic reticulum protein, Nogo-B, facilitates alcoholic liver disease through regulation of kupffer cell polarization.

Conclusion

Publications

An endoplasmic reticulum protein, Nogo-B, facilitates alcoholic liver disease through regulation of kupffer cell polarization.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets