Disturbed Matrix Metalloproteinase Pathway in Both Age-Related Macular Degeneration and Alzheimer’s Disease

Figure 4

Presence of LMMC in brain tissue. Brain supernatant preparations (3.35 mg protein/0.75 mls) were fractionated on a gel filtration column (Sepharose CL-6B) and the resultant fractions were examined by zymography. Representative samples were obtained from two control (Gels 1 and 2) and two AD (Gels 7 and 9) donors. Gel lanes labelled Ext represent the content of MMP species present in the original supernatant extract applied to the column. The fractionation procedure resulted in considerable dilution of the MMP species. Due to its large size, the LMMC complex is expected to be appear at the elution forefront (fractions 11–13) followed by elution of the free MMP species (fractions 24 onwards). In control samples, LMMC constituents (HMW2 and pro-MMP9) are observed at the elution forefront but the gels show absence of free MMP species. In AD samples, MMPs associated with the LMMC complex are just discernible at the elution forefront but the gels are dominated by the presence of free MMP species.