HSD17B13 (hydroxysteroid 17-beta dehydrogenase 13) mRNA

Class

GalNAc-conjugated antisense oligonucleotide (ASO)

Pathway

RNase H-mediated hepatic mRNA knockdown — silences HSD17B13, a liver-disease-modifier gene, reducing hepatocyte lipid droplet-associated enzyme activity implicated in NASH progression

HSD17B13 is an enzyme found on lipid droplets inside liver cells (hepatocytes), where it participates in lipid handling. Human genetics identified a naturally occurring variant that produces little or no functional HSD17B13 protein; carriers of this variant show reduced risk of progressive liver disease, including inflammation and fibrosis associated with nonalcoholic steatohepatitis (NASH), without apparent harm. This human validation makes HSD17B13 an attractive target for pharmacological silencing rather than direct enzyme inhibition. The approach used here is a GalNAc-conjugated antisense oligonucleotide (ASO): a short synthetic nucleic acid strand chemically linked to N-acetylgalactosamine sugars that bind a receptor expressed almost exclusively on hepatocytes, concentrating the drug in the liver. Once inside the cell, the ASO binds the HSD17B13 messenger RNA (mRNA) by complementary base pairing, recruiting an enzyme called RNase H that cleaves the mRNA, preventing production of new protein. By mimicking the protective genetic state, this mechanism aims to slow fatty liver disease progression toward fibrosis and cirrhosis. Because the effect is liver-restricted and mirrors a variant already observed in healthy populations, the mechanism carries a distinct rationale compared with broader metabolic or anti-inflammatory approaches to NASH.