Hepatocytes are very difficult to expand in vitro. A few studies have demonstrated that chemical cocktails with growth factors or Wnt ligands can support long-term expansion of hepatocytes via dedifferentiation. However, the culture conditions are complex, and clonal expansion of hepatic progenitors with full differentiation capacity are rarely reported. Here, we discover IL6, combined with EGF and HGF, promotes long-term expansion (>30 passages in ~150 days with theoretical expansion of ~10³⁵ times) of primary mouse hepatocytes in vitro in simple 2D culture, by converting hepatocytes into induced hepatic progenitor cells (iHPCs), which maintain the capacity of differentiation into hepatocytes. IL6 also supports the establishment of single hepatocyte-derived iHPC clones. The summation of the downstream STAT3, ERK and AKT pathways induces a number of transcription factors which support rapid growth. This physiological and simple way may provide ideas for culturing previously difficult-to-culture cell types and support their future applications.

肝细胞很难在体外扩增。一些研究表明，含有生长因子或 Wnt 配体的化学混合物可以通过去分化支持肝细胞的长期扩增。但培养条件复杂，克隆扩增具有完全分化能力的肝祖细胞鲜见报道。在这里，我们发现 IL6 与 EGF 和 HGF 相结合，促进了长期扩增（在 ~150 天内 >30 代，理论扩增为 ~10 ³⁵通过将肝细胞转化为诱导性肝祖细胞 (iHPC)，在简单的二维培养中对原代小鼠肝细胞进行体外培养，从而保持分化为肝细胞的能力。IL6 还支持建立单个肝细胞衍生的 iHPC 克隆。下游 STAT3、ERK 和 AKT 通路的总和诱导了许多支持快速生长的转录因子。这种生理和简单的方法可能为培养以前难以培养的细胞类型提供思路，并支持它们未来的应用。