Processed Buthus martensii Karsch scorpions ameliorate diet-induced NASH in mice by attenuating Kv1.3-mediated macrophage activation

Ethnopharmacological relevance: Processed Buthus martensii Karsch (BmK) scorpion, also known as Quan-Xie, is a traditional Chinese medicine that is clinically used for the treatment of NAFLD due to its Tong-Luo-San-Jie effects. Our previous study showed that aqueous extract of processed BmK scorpion venom gland (pVg AE) inhibited macrophage inflammation by targeting Kv1.3 and identified the thermostable peptide BmKK2 as a potent Kv1.3 blocker.

Aim of the study: This study examined the therapeutic effects of processed BmK scorpions on NASH, specifically focusing on the involvement of their anti-inflammatory effects mediated by macrophage-expressed Kv1.3 in NASH.

Materials and methods: In the present study, the anti-NASH effects of pVg AE were evaluated in high-fat diet (HFD)-induced NASH mouse models. Additionally, the in vitro anti-inflammatory mechanisms of pVg AE and BmKK2 were assessed using a palmitic acid (PA)-induced mouse bone marrow-derived macrophages (BMDMs) inflammation model. Protein and cytokine expression related to the Kv1.3-NF-κB pathway was analyzed by real-time PCR, immunoblotting and ELISA. The effect of pVg AE and BmKK2 on potassium channels was detected by whole-cell voltage-clamp recordings on transfected HEK293T cells or mouse BMDMs. Calcium ion imaging was used to evaluate intracellular calcium signaling. Furthermore, the study utilized Kv1.3 siRNA and a BMDMs and hepatocytes co-culture model to investigate the specific role of Kv1.3 in mediating the anti-NASH effects of pVg AE and BmKK2.

Results: Lipid accumulation upregulated Kv1.3 expression in macrophages in vivo and in vitro. However, pVg AE significantly reduced Kv1.3 expression and Kv1.3-positive macrophage infiltration. Treatment with pVg AE improved obesity, insulin resistance (IR), hepatic steatosis (HS), inflammation, and fibrosis in HFD-fed mice. Mechanistically, pVg AE and BmKK2 inhibited macrophage inflammation by targeting Kv1.3, which reduced PA-induced intracellular Ca²⁺ levels, resulting in the inhibition of the NF-κB pathway and TNFα release.

Conclusions: This study demonstrates that Kv1.3-mediated macrophage inflammation is involved in the pathogenesis and treatment of NASH. pVg AE effectively alleviates metabolic stress-induced NASH by inhibiting this inflammation.