Thyroid hormone receptor-beta agonist HSK31679 alleviates MASLD by modulating gut microbial sphingolipids.

Abstract

Background & aims: As the first approved medication for metabolic dysfunction-associated steatohepatitis (MASH), thyroid hormone receptor-beta (THR-β) agonist MGL-3196 (Resmetirom) is highly spotlighted as the liver-directed, bioactive oral drug. However, it was also identified with remarkable heterogeneity of individual clinical efficacy and its interference with gut microbiota in host hepatoenteral circulation was still undocumented.

Methods: We compared MASH attenuation by MGL-3196 and its derivative drug HSK31679 between germ-free (GF) and specific-pathogen free (SPF) mice to evaluate the role of gut microbiota. Then cross-omics analyses of microbial metagenome, metabolome and single-cell RNA-sequencing were applied into the randomized, double-blind, placebo-controlled multiple-ascending-dose (MAD) cohort of HSK31679 treatment (n = 40), to comprehensively investigate the altered gut microbiota metabolism and circulating immune signatures.

Results: HSK31679 outperformed MGL-3196 in ameliorating MASH diet-induced steatohepatitis of SPF mice but not GF mice. In the MAD cohort of HSK31679, relative abundance of B. thetaiotaomicron was significantly enriched to impair glucosylceramide synthase (GCS)-catalyzed monoglucosylation of microbial Cer(d18:1/16:0) and Cer(d18:1/24:1). In stark contrast to the non-inferiority MASH resolution between MGL-3196 and HSK31679 for GF^BTΔGCS mice, HSK31679 manifested superior steatohepatitis alleviation than MGL-3196 for GF^BTWT mice, due to its steric hindrance with R123 and Y401 of gut microbial GCS. For participants with high fecal GCS activity, the administration of 160 mg HSK31679 induced a shift in peripheral compartments towards an immunosuppressive niche, characterized by decreased CD8α⁺ dendritic cells and MINCLE⁺ macrophages.

Conclusions: This study provided novel insights into the indispensable gut microbiota for HSK31679 treatment, which revealed microbial GCS may serve as its prognostic biomarker of MASH treatment, as well as the new target for further strategies of microbiota-based MASH therapeutics.

Impact and implications: Remarkable heterogeneity of individual clinical efficacy of THR-β agonists and their interferences with microbiome in host hepatoenteral circulation are poorly understood. In our current germ-free mice models and randomized, double-blind multiple-dose cohort study, we identified microbial GCS as the prognostic biomarker of HSK31679 treatment, as well as the new target for further strategies of microbiota-based MASLD therapeutics.