Hnf1aos1 as a Metabolic Coordinator of Hepatic Lipid Homeostasis and Feedback Control-Raw qPCR Data

Abstract: Long noncoding RNAs (lncRNAs) have emerged as critical regulators of hepatic metabolism and disease progression. The hepatocyte nuclear factor 1 alpha antisense 1 (HNF1A-AS1) lncRNA modulates liver‑specific transcription factors; however, its physiological role in diet‑dependent lipid homeostasis remains poorly defined. In this study, we investigated the mouse ortholog, Hnf1aos1, using AAV-mediated knockdown in C57BL/6J mice fed either a chow diet (10% kcal from fat) or a high‑fat diet (HFD; 60% kcal from fat) for 12 weeks. Metabolic phenotyping included hepatic lipid quantification, histological analysis, serum biochemistry, and quantitative gene expression profiling. Loss of Hnf1aos1 produced distinct, diet‑dependent alterations in hepatic lipid handling. Under chow conditions, knockdown mice exhibited selective hepatic cholesterol accumulation (6.10 ± 2.9 mg/g tissue vs. 3.51 ± 1.1 mg/g in controls), accompanied by dysregulation of cholesterol clearance pathways. In contrast, under HFD conditions, knockdown precipitated severe macrovesicular degeneration, with hepatic triglyceride levels approximately doubled relative to HFD‑fed controls (51.72 ± 19.8 mg/g vs. 26.34 ± 11.9 mg/g) and a markedly elevated triglyceride‑to‑cholesterol ratio (TG:TC ≈ 6.1:1). Chow/Kd mice gained sig-nificantly less weight than chow‑fed controls, whereas HFD/Kd mice exhibited weight gain comparable to HFD controls despite severe hepatic steatosis. This paradoxical phenotype suggests impaired metabolic feedback, in which compensatory upregulation of Hnf1a transcription is associated with increased ex-pression of lipid‑associated genes such as Cd36, despite profound lipid overload. Collectively, these findings identify Hnf1aos1 as a regulator of hepatic lipid homeostasis whose loss produces a phenotype consistent with inappropriate lipid accumulation during nutrient excess, without defining the underlying molecular mechanism. Our results support a role for Hnf1aos1 in shaping hepatic metabolic plasticity and provide insight into lncRNA‑associated MASLD phenotypes.