Even though an exact mechanism remains unclear, in a recent study GHK and its copper complexes decreased TNF-alpha-dependent IL-6 secretion in normal human dermal fibroblasts.
LDL in the blood binds to LDL receptors on the surface of fibroblasts; these receptors concentrate in coated pits (they are about 200x as concentrated here as along the rest of the cell’s plasma membrane) and are internalised when the pit becomes a coated vesicle.
In the lysosomal storage disorders Gaucher’s and Tay-Sachs disease, endoplasmic reticulum-associated degradation (ERAD) prevents the native folding of mutated lysosomal enzymes in a patient’s fibroblasts.