Margatoxin mitigates CCl4‑induced hepatic fibrosis in mice via macrophage polarization, cytokine secretion and STAT signaling

Abstract

A number of macrophage phenotypes have been previously identified as crucial regulators in the progression of hepatic fibrosis (HF). Cytokines from macrophages or Kupffer cells (KCs) have also been identified to be important regulators in HF. Blocking Kv1.3 in models of HF, regulating macrophage polarization and cytokine secretion have not yet been assessed as potential treatments options for this condition. In the current study, a model of carbon tetrachloride (CCl4)-induced HF was established and examined the effects of margatoxin (MgTX; an inhibitor of Kv1.3) on HF. Hematoxylin and eosin, Masson's trichrome and immunohistochemistry staining were performed to determine whether MgTX can alleviate liver fibrosis. To elucidate the mechanisms through which MgTX attenuates liver injury, reverse transcription-quantitative PCR and western blot analysis were used to detect polarized macrophage markers in RAW264.7 cells and cytokines were examined using ELISA. Furthermore, macrophage polarization signal transducer and activator of transcription (STAT) signaling, which is associated with macrophage polarization, was identified in RAW264.7 cells. The results revealed that MgTX protected the mice from CCl4-induced liver fibrosis. Furthermore, MgTX decreased the expression of M1 phenotype biomarkers, and increased the expression of M2 phenotype biomarkers in CCl4-induced HF. Additionally, the production of pro-inflammatory cytokines was decreased and interleukin-10 production was increased in the serum of mice with HF injected with MgTX. Furthermore, MgTX was found to regulate the expression of M1 markers by suppressing p-STAT1 activity and increasing the expression of M2 markers by promoting p-STAT6 activity. On the whole, the findings of this study demonstrate that MgTX is able to alleviate CCl4-induced HF in mice, possibly via macrophage polarization, cytokine secretion and STAT signaling.

Macrophage Polarization and Its Role in Liver Disease

“…Therefore, the inhibition of M1 and M2 macrophage polarization may respectively alleviate CCl 4 - and schistosome infection-induced LF. For example, margatoxin reduced M1 and increased M2 macrophage polarization by inhibiting STAT1 and promoting the phosphorylation of STAT6, which down-regulated pro-inflammatory cytokines and increased IL-10 expression, alleviating CCl 4 -induced LF in mice ( 195 ). Corilagin inhibited M2 polarization by inhibiting IL-13Rα1 signaling pathway, which alleviated schistosome egg-induced LF ( 196 ).…”

Anti-inflammatory effects of FS48, the first potassium channel inhibitor from the salivary glands of the flea Xenopsylla cheopis

“…For example, MgTx can suppress the maturation, migration, phagocytosis, inflammatory cytokines release, Kv-like currents, and Ca 2+ influx of LPS-stimulated DCs ( 37 ). Consistently, MgTx is also reported to alleviate CCl 4 -induced HF in mice through the regulation of cytokine secretion and the polarization of macrophages ( 38 ). Furthermore, according to another study by our group (unpublished data), FS48 has similar suppression effects of most Kv1.3 inhibitors reported on T cells and can relieve the delayed-type hypersensitivity response caused by skin-homing effector memory T cells.…”

Increased expression levels of inflammatory cytokines and adhesion molecules in lipopolysaccharide‑induced acute inflammatory apoM‑/‑ mice

“…Hepatic samples were fixed in 10% formalin for 24 h at room temperature and then embedded in paraffin. Hepatic sections were cut into 5-µm-thick slices and used for H&E staining according to the established method ( 21 ). All slides were examined under an inverted microscope (Olympus IX73, magnification, ×200) by an experienced pathologist.…”