Parallel expression profiling of hepatic and serum microRNA-122 associated with clinical features and treatment responses in chronic hepatitis C patients

Abstract

MicroRNAs (miRNAs) are small, non-coding RNAs that regulate a variety of biological processes. Recently, human liver-specific miRNA miR-122 has been reported to facilitate hepatitis C virus (HCV) replication in liver cells. HCV is one of the leading causes of liver diseases worldwide. In Pakistan, the estimated prevalence is up to 10%. Here, we report hepatic and serum miR-122 expression profiling from paired liver and serum samples from treatment-naive chronic hepatitis C (CHC) patients and controls. We aimed to elucidate the biomarker potential of serum miR-122 for monitoring disease progression and predicting end treatment response (ETR). Hepatic miR-122 levels were significantly down-regulated in CHC patients. A significant inverse correlation was observed between hepatic and serum miR-122 levels, indicating that serum miR-122 levels reflect HCV-associated disease progression. Both hepatic and serum miR-122 were significantly correlated (P < 0.05) with several clinicopathological features of CHC. Receiver operator curve analysis showed that serum miR-122 had superior discriminatory ability even in patients with normal alanine transaminase levels. Multivariate logistic regression analysis highlighted pre-treatment serum miR-122 levels as independent predictors of ETR. In conclusion, serum miR-122 holds the potential to serve as a promising biomarker of disease progression and ETR in CHC patients.

Figure 1. Relative expression levels of microRNA-122.

The expression levels of hepatic (a) and serum (b) miR-122 in chronic hepatitis C patients with normal and elevated alanine transaminase (ALT) levels were compared with those of healthy controls. Boxes represent range, median and quartiles of the normalized miR-122 expression (∆Cq) levels. Asterisks indicate level of significant difference between analysed groups and are as follows: ****P < 0.0001, ***P < 0.001, **P < 0.01 and *P < 0.05.

Figure 2. Correlation analysis of hepatic miR-122.

The expression levels of hepatic miR-122 were significantly correlated with the following clinicopathological features in chronic hepatitis C patients: (a) Necroinflammatory scores. (b) Fibrosis scores. (c) Prothrombin time (PT). (d) International normalized ratio (INR). (e) Alanine transaminase (ALT). (f) Aspartate transaminase (AST). (g) AST/ALT ratio. (h) Total proteins (TP), and (i) Gamma-glutamyl transferase (γ-GT).

Figure 3. Correlation analysis of serum miR-122.

The expression levels of serum miR-122 were significantly correlated with the following clinicopathological features in chronic hepatitis C patients: (a) Necroinflammatory scores. (b) Fibrosis scores. (c) Prothrombin time (PT). (d) International normalized ratio (INR). (e) Alanine transaminase (ALT). (f) Aspartate transaminase (AST). (g) Albumin (Alb). (h) Gamma-glutamyl transferase (γ-GT). (i) AST/ALT ratio, and (j) Total cholesterol (TC).

Figure 4. Expression levels of hepatic and serum miR-122 in sustained virological responder (SVR) and non-responder (NR) groups.

The differences in expression levels of hepatic (a) and serum (b) miR-122 were computed between SVR and NR groups. Boxes represent range, median and quartiles of the normalized miR-122 expression (∆Cq) levels. Asterisks indicate level of significant difference between analysed groups and are as follows: ****P < 0.0001, ***P < 0.001, **P < 0.01 and *P < 0.05.

Figure 5. Receiver operator characteristic (ROC) curve analysis.

ROC curves were drawn and the area under the curve (AUC) was calculated to evaluate and compare the diagnostic and prognostic potential of serum miR-122 and alanine transaminase (ALT) levels in (a) chronic hepatitis C (CHC) patients (normal plus elevated ALT group) versus healthy controls, (b) CHC patients (normal ALT group) versus healthy controls, (c) SVR group versus NR+RR group, and in the (d) SVR group versus NR only group.