scholarly journals Integrated gut–liver-on-a-chip platform as an in vitro human model of non-alcoholic fatty liver disease

2020 ◽  
Author(s):  
Jiandong Yang ◽  
Yoshikazu Hirai ◽  
Kei Iida ◽  
Shinji Ito ◽  
Marika Trumm ◽  
...  

AbstractNon-alcoholic fatty liver disease (NAFLD) afflicts a large percentage of the population, but no effective treatments have been established so far because of the unsuitability of in vitro assays and experimental models using animals. By co-culturing human gut and liver cell lines interconnected via microfluidics for a closed circulation loop, we created a gut–liver-on-a-chip (iGLC) platform as an in vitro human model of the gut–liver axis (GLA) for the initiation and progression of NAFLD. Microscopic high-content analysis followed by mRNA sequencing showed that co-culturing the gut and liver cells significantly affected each cell type compared to culturing them separately. NAFLD-inducing free fatty acids (FFAs) accumulated in the gut cells and elevated gene expressions associated with retinol metabolism and glucuronidation. The FFA-treated liver cells accumulated intracellular lipid droplets and showed an increase in gene expressions associated with a cellular response to copper ions and endoplasmic reticulum stress. As an in vitro human GLA model, the iGLC platform may serve as an alternative to animal experiments for investigating NAFLD mechanisms.

2018 ◽  
Vol 23 (2) ◽  
pp. 84
Author(s):  
Eunice Limantara ◽  
Felicia Kartawidjajaputra ◽  
Antonius Suwanto

Early detection of insulin resistance (IR) or non-alcoholic fatty liver disease (NAFLD) is crucial to preventing future risks of developing chronic diseases. The Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), Liver Fat Score (LFS), and Fatty Liver Index (FLI) are generally employed to measure severity stages of IR and NAFLD. The study of gene expressions could explain the molecular mechanisms that occur early on in IR and NAFLD; thus providing potential early markers for both diseases. This study was conducted to evaluate the gene expressions that could potentially be early markers of IR and NAFLD. All participants (n = 21) had normal blood glucose and were categorized as without hepatosteatosis (n = 10), at higher risk of hepatosteatosis (n = 6), and hepatosteatosis (n = 5). Gene expression analysis was performed using the 2-∆∆CT relative quantification method. There were significant differences in galnt2 (p < 0.002) and sirt1 (p < 0.010) expression between the first and the third tertiles of HOMA-IR; and in ptpn1 (p < 0.012) expression between the first and the second tertiles of LFS. In conclusion, the expressions of galnt2 and sirt1 could be used as early markers of IR, while the expression of ptpn1 could be employed as an early marker of NAFLD.


Author(s):  
Lingling Guan ◽  
Lan Guo ◽  
Heng Zhang ◽  
Hao Liu ◽  
Yuan Qiao ◽  
...  

Abstract Background and Purpose: The autophagic degradation of lipid droplets (LDs), termed lipophagy, is the main mechanism contributing to lipid consumption in hepatocytes. The identification of effective and safe natural compounds that target lipophagy to eliminate excess lipids may be a potential therapeutic strategy for non-alcoholic fatty liver disease (NAFLD). Here, we investigated the effects of naringin on NAFLD and the underlying mechanism. Experimental Approach: The role of naringin was investigated in mice fed a high-fat diet (HFD) to induce NAFLD, as well as in AML12 cells and primary hepatocytes stimulated by palmitate (PA). Transcription factor EB (TFEB)-knockdown AML12 cells and hepatocyte-specific TFEB-knockout mice were also used for the mechanism study. In vivo and in vitro studies were conducted using transmission electron microscopy, immunofluorescence techniques and western blot analysis. Key Results: We found that naringin treatment effectively relieved HFD-induced hepatic steatosis in mice and inhibited palmitate (PA)-induced lipid accumulation in hepatocytes. The increased p62 and LC3-II levels observed with excess lipid-support autophagosome accumulation and impaired autophagic flux. Treatment with naringin restored TFEB-mediated lysosomal biogenesis, thereby promoting the fusion of autophagosomes and lysosomes, restoring impaired autophagic flux and further inducing lipophagy. However, the knockdown of TFEB in hepatocytes or the hepatocyte-specific knockout of TFEB in mice abrogated naringin-induced lipophagy, which eliminated the therapeutic effect of naringin on hepatic steatosis. Conclusion and Implications: These results demonstrate that TFEB-mediated lysosomal biogenesis and subsequent lipophagy play essential roles in the ability of naringin to mitigate hepatic steatosis and suggest that naringin is a promising drug for treating or relieving NAFLD.


2017 ◽  
Vol 23 (2) ◽  
pp. 204 ◽  
Author(s):  
Tomasz Kostrzewski ◽  
Terri Cornforth ◽  
Sophie A Snow ◽  
Larissa Ouro-Gnao ◽  
Cliff Rowe ◽  
...  

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