High-Level Secretory Expression of Recombinant Type XVII Human-like Collagen in Komagataella phaffii

Type XVII collagen (COL17) is crucial for skin integrity but difficult to produce. To achieve high-level secretory expression, a human COL17 segment was designed and cloned into the pPIC9K vector with six different α-mating factor signal peptides and integrated into Komagataella phaffii GS115. Fed-batch fermentation in a 5 L bioreactor yielded 4.7 g/L of recombinant COL17. Functional assays showed that it promoted the proliferation of human skin fibroblast (HFF) and immortalized keratinocytes (HaCaT), upregulated COL1A1, COL3A1, and TIMP1 in HFF cells, and enhanced skin barrier-related genes (KRT1, KRT5, KRT10, KRT14, IVL, LOR, FLG) in HaCaT cells. In a UVB-induced photoaging model, COL17 reduced reactive oxygen species (ROS) and matrix metalloproteinase 3 (MMP3) activity. This recombinant collagen exhibits photoprotective, regenerative, and barrier-enhancing activities, offering potential for skincare and tissue engineering.