Liver Biopsy Hydroxyproline Content Is a Diagnostic for Hepatocellular Carcinoma in Murine Models of Nonalcoholic Steatohepatitis

miR-12135 ameliorates liver fibrosis accompanied with the downregulation of integrin subunit alpha 11

Cirrhosis is becoming one of the most common diseases worldwide. Abnormal upregulation of transforming growth factor β (TGF-β) signaling plays a pivotal role in the excess activation of hepatic stellate cells. However, an efficient countermeasure against abnormal hepatic stellate cell activation is yet to be established because TGF-β signaling is involved in several biological processes. Herein, we demonstrated the antifibrotic effect of miR-12135, a microRNA with unknown function upregulated by isoflavone. Comprehensive transcriptome assay demonstrated that miR-12135 suppressed Integrin Subunit Alpha 11 (ITGA11) and that ITGA11 expression is correlated with alpha smooth muscle actin expression in patients with cirrhosis. miR-12135 suppressed the expression level of ITGA11 and liver fibrosis. Importantly, ITGA11 is overexpressed in activated hepatic stellate cells, whereas ITGA11 knockout mice are viable and fertile. In conclusions, the miR-12135/ITGA11 axis can be an ideal therapeutic target to suppress fibrosis by precisely targeting abnormally upregulated TGF-β signaling in hepatic stellate cells.

Hydroxyproline metabolism enhances IFN-γ-induced PD-L1 expression and inhibits autophagic flux

The immune checkpoint protein PD-L1 plays critical roles in both immune system homeostasis and tumor progression. Impaired PD-1/PD-L1 function promotes autoimmunity and PD-L1 expression within tumors promotes immune evasion. If and how changes in metabolism or defined metabolites regulate PD-L1 expression is not fully understood. Here, using a metabolomics activity screening-based approach, we have determined that hydroxyproline (Hyp) significantly and directly enhances adaptive (i.e., IFN-γ-induced) PD-L1 expression in multiple relevant myeloid and cancer cell types. Mechanistic studies reveal that Hyp acts as an inhibitor of autophagic flux, which allows it to regulate this negative feedback mechanism, thereby contributing to its overall effect on PD-L1 expression. Due to its prevalence in fibrotic tumors, these findings suggest that hydroxyproline could contribute to the establishment of an immunosuppressive tumor microenvironment and that Hyp metabolism could be targeted to pharmacologically control PD-L1 expression for the treatment of cancer or autoimmune diseases.

Identification of disease-associated microRNA in a diet-induced model of nonalcoholic steatohepatitis

Emerging evidence suggests that microRNA dysregulation plays an important role in nonalcoholic steatohepatitis. Using a model of diet-induced liver disease that progresses to fibrosis and hepatocellular carcinoma, we identify a set of 22 microRNA with robust correlation with liver enzyme levels and liver collagen content. These disease-asssociated miRs play pivotal roles in steatosis, extracellular matrix deposition and liver cancer, and may form the basis for identification of therapeutic strategies against this form of liver disease.

Hepatic mRNA Expression Levels of the Oncogenes Alpha-Fetoprotein and Osteopontin as Diagnostics for Liver Cancer in a Murine Model of Diet-Induced Non-Alcoholic Steatohepatitis

Non-alcoholic steatohepatitis (NASH) is associated with an increased risk of hepatocellular carcinoma (HCC). Expression levels of hepatic oncogenes, alpha-fetoprotein (afp) and osteopontin (opn)/secreted phosphoprotein 1 (spp1), were investigated using a model of diet-induced NASH. Mice were randomized to a standard diet or a fast-food diet (FFD) for 17 months. Livers from the FFD cohort exhibited hallmark characteristics of NASH with liver fibrosis, with a subset of animals exhibiting HCC. Expression levels of hepatic afp and opn/spp1 were elevated ~2.5 and ~5-fold, respectively, in the FFD cohort. Hepatic opn/spp1 exhibited a direct (r = 0.65) and significant (p < 0.01) correlation with liver hydroxyproline content. Receiver operating characteristic (ROC) curve analysis for hepatic afp, as a diagnostic for HCC, returned an area under (AU) ROC 0.84, a sensitivity of 87.5%, a specificity of 77% and a threshold of >1.05-fold change in mRNA level. The use of hepatic opn/ssp1 as a diagnostic for HCC returned an AUROC 0.88, a sensitivity of 83.3%, a specificity of 86.7% and a threshold of >2.4-fold change in mRNA level. These data point to a transformation of NASH to an oncotype with hepatic oncogene levels as a diagnostic for NASH.

Collagen Characterization in a Model of Nonalcoholic Steatohepatitis with Fibrosis; A Call for Development of Targeted Therapeutics

Left untreated, nonalcoholic fatty liver disease can progress to nonalcoholic steatohepatitis (NASH), fibrosis, and end-stage liver disease. To date, few if any therapies have proven effective against NASH with fibrosis. Quantification and qualification of hepatic scar might enable development of more effective targeted therapies. In a murine model of NASH induced by diet, we characterized fibrillar collagen deposition within the hepatic parenchyma. At harvest, livers from the modified diet cohort exhibited NASH with fibrosis. Transcriptomic analysis of hepatic tissue revealed increased col1a1, col1a2, and col3a1, each of which correlated directly with hepatic hydroxyproline content. Circular polarized microscopic analysis of Picrosirius red-stained liver sections revealed deposition of collagen type I within the parenchyma. Development of therapeutics designed to mitigate collagen type I accumulation might prove effective in NASH with fibrosis.