Additive hepatotoxicity of seneciphylline and lasiocarpine mixtures: multi-omics insights into P53 driven apoptosis and a Warburg-like metabolic reprogramming.

Pyrrolizidine alkaloids (PAs) are widespread food contaminants whose co-occurrence poses serious yet poorly understood cumulative health risks. Here, using primary mouse hepatocytes and C57BL/6J mice combined with concentration addition (CA) and combination index (CI) models, we demonstrate that co-exposure to the prevalent 1,2-unsaturated PAs seneciphylline (Sp) and lasiocarpine (La) produces strictly additive hepatotoxicity across a wide concentration range (CI ≈ 1.0; 1/8 EC50 to 8 EC50). Mechanistically, combined exposure triggers mitochondrial calcium overload, ROS burst, and membrane potential collapse, leading to ultrastructural disintegration. Integrated targeted metabolomics and MitoCarta 3.0-based transcriptomics reveal a previously unappreciated Warburg-like metabolic reprogramming characterized by TCA cycle uncoupling, ATP depletion despite heightened cycle activity, and intracellular lactate acidosis driven by Pdk1-mediated pyruvate dehydrogenase inhibition and Slc16a3 downregulation. In vivo, co-exposure faithfully recapitulates human hepatic sinusoidal obstruction syndrome (HSOS) pathology, with additive activation of P53 target genes (Pmaip1, Hrk, Septin4) that dismantle anti-apoptotic BCL-2 defenses, culminating in cytochrome c release and caspase-9 cleavage. This multi-omics investigation establishes that additive hepatotoxicity of Sp and La arises from the convergence of two lethal cascades P53-driven mitochondrial apoptosis and metabolic energy catastrophe providing a mechanistic rationale for treating structurally related 1,2-unsaturated PAs as toxicological dose-surrogates in cumulative food safety risk assessment.