# The Effect of Ursodeoxycholic Acid (UDCA) on Serum Expression of miR-34a and miR-506 in Patients with Chronic Cholestatic Liver Diseases

## TL;DR

This study shows that ursodeoxycholic acid (UDCA) reduces specific microRNAs and inflammatory markers in patients with primary biliary cholangitis (PBC), offering new insight into its therapeutic mechanism.

## Contribution

The study reveals UDCA's effect on miR-34a, miR-506, TREM-2, and sCD163 in PBC, providing novel mechanistic understanding of UDCA's anti-inflammatory role.

## Key findings

- Baseline miR-34a and miR-506 levels were elevated in PBC patients and reduced after UDCA therapy.
- UDCA decreased serum TREM-2 and sCD163 levels in PBC patients.
- In vitro, UDCA suppressed LPS-induced miR-34a and ADAM17 while enhancing TREM-2 expression.

## Abstract

Ursodeoxycholic acid (UDCA) is widely used to treat cholestatic liver diseases such as primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), yet its molecular mechanisms remain unclear. This study investigated the impact of long-term UDCA therapy on circulating levels of the microRNAs miR-34a and miR-506, which are implicated in PBC pathogenesis, and explored associated changes in inflammatory markers and signaling pathways. Serum samples from patients with PBC and PSC were collected before and after UDCA treatment and analyzed for miRNA expression as well as levels of TREM-2 and sCD163. In vitro studies using human cholangiocytes and lipopolysaccharide (LPS) stimulation assessed changes in the expression of miR-34a, TREM-2, and ADAM17. The results showed that the baseline levels of miR-34a and miR-506 were significantly elevated in PBC patients compared to controls and were significantly reduced after UDCA therapy in PBC but not in PSC. UDCA also decreased serum levels of TREM-2 and sCD163. In vitro, it suppressed the LPS-induced expression of miR-34a and ADAM17 while enhancing TREM-2 expression. Single-cell RNA sequencing of liver tissue and immunofluorescence staining confirmed TREM-2 expression in cholangiocytes. These findings suggest that UDCA modulates key inflammatory pathways and miRNAs in PBC, providing mechanistic insights into its therapeutic effect