Refolding-free, tag-free production of functional platelet-derived growth factor-BB at gram-per-liter scale in...

Platelet-derived growth factor-BB (PDGF-BB) is a homodimeric growth factor essential for angiogenesis, wound healing, and tissue regeneration with well-established therapeutic potential. However, scalable microbial production of bioactive PDGF-BB is hindered by its structural complexity, requiring precise folding and disulfide bond formation. In the present study, we developed a recombinant Escherichia coli expression and purification strategy to obtain soluble PDGF-BB. Fusion with 6HFh8 increased solubility and streamlined purification. After TEV protease cleavage, a two-step process involving immobilized metal affinity and cation-exchange chromatography yielded tag-free PDGF-BB with >95% purity, as confirmed using sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE) and reverse-phase high-performance liquid chromatography (RP-HPLC). High-cell-density fed-batch fermentation further increased productivity, achieving gram-per-liter-scale production of recombinant protein. Functional assays, including cell migration and wound-healing assays, revealed that the recombinant protein retained comparable biological activity to that of a commercial standard. This workflow eliminates the need for refolding, simplifies production, and enables the reproducible, scalable preparation of bioactive rhPDGF-BB. The approach may be applicable to the microbial production of other disulfide-rich growth factors, thereby expanding opportunities for therapeutic and biotechnological applications.