Long-acting STK25 antisense oligonucleotide as a therapeutic candidate for MASLD

Metabolic dysfunction–associated steatotic liver disease (MASLD) is the most prevalent chronic liver disorder worldwide and a leading cause of liver-related morbidity. Insulin resistance and hepatic lipid metabolism dysfunction are recognized as central pathological mechanisms, yet no therapy is currently approved specifically for MASLD. Antisense oligonucleotides (ASOs) are single-stranded nucleotide drugs with high target specificity and long-lasting activity, making them well suited for chronic metabolic diseases. Here, we describe a novel ASO candidate targeting serine/threonine kinase 25 (STK25), a lipid droplet–associated kinase implicated in MASLD pathogenesis. In three human cell lines, the ASO (c337) robustly reduced STK25 expression. For in vivo validation, we generated Gc337 by GalNAc conjugation to enable liver-specific delivery. In a high-fat diet-induced MASLD mouse model, Gc337 significantly improved insulin sensitivity, reduced hepatic lipid accumulation, and lowered body weight, with efficacy comparable to resmetirom, the only FDA-approved therapy for metabolic-associated steatohepatitis. A single injection sustained >50% hepatic Stk25 knockdown for 35 days without hepatotoxicity, underscoring its long-acting therapeutic profile. Importantly, c337 was designed to avoid all known single-nucleotide polymorphisms (SNPs), ensuring efficacy across genetically diverse populations. Together, these findings establish Gc337 as a durable, SNP-aware, and clinically translatable nucleic acid–based therapeutic candidate for MASLD. Overall design: In a high-fat diet-induced MASLD mouse model, mice were treated with either resmetirom or STK25 knockdown using Gc337. After the treatment period, liver tissues were collected for sequencing analysis.代谢功能障碍相关脂肪性肝病（Metabolic dysfunction-associated steatotic liver disease, MASLD）是全球范围内最常见的慢性肝脏疾病，也是引发肝病相关发病率升高的首要原因。胰岛素抵抗与肝脏脂质代谢紊乱被认定为其核心病理机制，但目前尚无专门针对MASLD的获批治疗方案。反义寡核苷酸（Antisense oligonucleotides, ASOs）是一类具备高靶点特异性与持久活性的单链核苷酸类药物，十分适配慢性代谢性疾病的治疗需求。本研究报道一款靶向丝氨酸/苏氨酸激酶25（serine/threonine kinase 25, STK25）的新型ASO候选药物，STK25是一种与脂滴相关的激酶，已被证实参与MASLD的发病进程。 在三株人类细胞系中，该ASO（c337）可强效下调STK25的表达水平。为开展体内验证，我们通过N-乙酰半乳糖胺（GalNAc）偶联技术制备了Gc337，以实现肝脏特异性递送。在高脂饮食诱导的MASLD小鼠模型中，Gc337可显著改善胰岛素敏感性、减轻肝脏脂质蓄积并降低体重，其疗效与目前唯一获美国食品药品监督管理局（FDA）批准的代谢相关脂肪性肝炎疗法瑞美替罗（resmetirom）相当。单次注射即可使肝脏Stk25的沉默效果维持超过50%达35天，且未观察到肝毒性，凸显了其长效治疗特性。值得关注的是，c337的设计规避了所有已知的单核苷酸多态性（single-nucleotide polymorphisms, SNPs），可确保在遗传多样性人群中均能实现稳定疗效。综上，本研究结果证实Gc337是一款兼具持久性、适配单核苷酸多态性且具备临床转化潜力的核酸类MASLD治疗候选药物。 整体实验设计：在高脂饮食诱导的MASLD小鼠模型中，小鼠分别接受瑞美替罗或Gc337介导的STK25敲低治疗。治疗周期结束后，采集肝脏组织用于测序分析。