Figure 2.

Changes in glomerular matrix composition are exacerbated with aging in Col4a mutant mice. Mouse glomerular extracts were fractionated to cellular and matrix fractions. All fractions were analyzed by mass spectrometry; proteins were identified with Mascot and quantified using Progenesis. (A) MATLAB was used for PCA of all detected proteins. Components 1 and 2 are presented; the percentage variance explained by component 1 is indicated on the x axis, and that of component 2 on the y axis. Samples were fractionated and the matrix fraction was further analyzed. (B–E) Volcano plots of proteins detected in matrix fractions demonstrate differential expression shown as log₂(fold change) compared with age-matched control on the x axis and −log₁₀(P value) onthe y axis. (B) Col4a3^−/− mice at 6–8 weeks old, (C) Col4a3^−/− mice at 16–18 weeks, (D) Col4a5^−/− mice at 6–8 weeks old, and (E) Col4a5^−/− mice at 16–18 weeks old. (F) Detected matrix proteins at 6–8 weeks of age were clustered in MeV using Euclidean distance complete-linkage clustering. The clustered dendrogram is presented as a heat map, with orange representing increased abundance in Col4a mutant relative to control. FC, fold change; WT, wild type.