HFF-1 Cells

HFF-1 is a human foreskin fibroblast cell line frequently used as a feeder layer for the culture of human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs). Derived from neonatal dermal tissue, HFF-1 cells provide essential extracellular matrix components and secrete key signaling molecules that promote hESC attachment and partially support their pluripotent state. These fibroblasts have been evaluated for their expression of several pluripotency-supporting growth factors, including TGFβ1, activin A, and fibroblast growth factor 2 (FGF-2), although their effectiveness as feeder cells can vary depending on the specific line and culture conditions.

In comparative studies, human foreskin fibroblasts like HFF-1 secrete detectable levels of FGF-2 and activin A, though their secretion levels are generally lower than those observed in mouse embryonic fibroblasts. HFF-1 cells also express BMP-4 mRNA and protein, although secreted levels of BMP-4 dimers are extremely low and often undetectable in conditioned media, likely due to intracellular sequestration or inhibition by gremlin. Importantly, the secretion of growth factors by HFF-1 is modulated by mitotic inactivation (e.g., mitomycin C treatment) and media composition (e.g., KnockOut Serum Replacement vs. fetal bovine serum). The ability of HFF-1 cells to support undifferentiated hESC growth correlates with their secretion of activin A and TGFβ1, although supplementation with exogenous activin A can improve the maintenance of pluripotency markers such as SSEA3 when these cells are used as feeders.

Overall, HFF-1 serves as a useful human-derived feeder cell model for stem cell culture systems aiming to reduce xeno-components. However, their capacity to maintain long-term undifferentiated hESC cultures is generally considered less robust than that of mouse-derived feeder cells unless combined with specific growth factor supplementation. Their human origin, however, makes them particularly attractive for clinical and translational stem cell applications where xeno-free conditions are essential.