A Selective Adenosine A3 Receptor Antagonist, HL3501, Has Therapeutic Potential in Preclinical Liver and Renal Fibrosis Models

Abstract

Background/aim: Adenosine and 4 G-protein-associated membrane receptors (A₁, A_2A, A_2B, and A₃) and their derivatives regulate the central nervous, cardiovascular, peripheral, and immune system. We developed a novel selective A₃ AR antagonist, HL3501, and examined its anti-fibrotic effects across various models.

Materials and methods: The anti-fibrotic activity of HL3501 was evaluated in three cell lines (HK2, LX2, and Primary hepatic stellate cell) and a methionine-choline-deficient (MCD) model including use of mouse pharmacokinetics (PK).

Results: HL3501 decreased alpha-smooth muscle actin (α-SMA) and collagen 1 in TGF-β1-induced pro-fibrotic activation in HK2 cells. HL3501 also inhibited TGF-β1-induced HSC activation, which resulted in reduction of α-SMA and fibronectin in LX2 and human primary HSCs. In the nonalcoholic fatty liver disease activity score (NAS) analysis, HL3501 showed improved anti-steatosis and anti-inflammatory activity. The mouse PK study revealed the oral bioavailability (%F) of HL3501 at 30 mg/kg and 60 mg/kg as 92.5 and 107.2%, respectively.

Conclusion: HL3501 presents anti-fibrotic effects in in vitro and in vivo studies. We also demonstrated that HL3501 is orally available and has a good bioavailability (BA >90%) profile from in mouse PK. HL3501, therefore, has a therapeutic potential for various fibrotic diseases, including those of liver and kidney tissues.

Keywords: A3 AR antagonist; HL3501; liver fibrosis; preclinical model; renal fibrosis.