Western blotting and densitometry analysis with Image J software (NIH) was performed with cell lysates equalized for protein or cell culture supernatants (conditioned media) equalized for total protein and cell number as previously described (Forsyth et al., 2007, Forsyth et al., 2002). To our knowledge there is no loading control marker for serum-free cell culture conditioned media for Fig. 2, all other western blotting data was normalized to densitometry values for the loading controls.
