Ferritin L and H protein and mRNA levels and iron deposits in the hippocampus of Pfn2^−/−mice. (A) Hippocampal ferritin L (Ftl) and ferritin H (Fth1) protein measured by western blotting are reduced in Pfn2 KO mice compared with WT controls. Ribosomal protein S6 levels were used for calibration. Graphs represent quantified data normalized to the WT control (set as 100%). Sample size (n) is indicated. (B) Hippocampal ferritin L (Ftl) and ferritin H (Fth1) mRNA levels measured by qPCR show no difference between Pfn2^−/− and WT control mice. mRNA expression was calibrated with ribosomal protein L19 (Rpl19) and TATA box binding protein (Tbp) mRNA expression and normalized to WT mice (set as 100%). Sample size (n) is indicated. (C) On the left side, TEM sample image from the hippocampus of a Pfn2^−/−mouse. The boxed area is magnified on its right. On the right side, sample image from the spleen of a Pfn2^−/− mouse. TEM images of hippocampus (second image) and spleen (third image from left) are at the same magnification for comparison of the aggregates size and morphology. Lamellae structures characterizing a mitochondrion are highlighted by a white arrow. Iron aggregates of different morphologies are indicated by yellow arrows: mitochondrial amorphous and big clustered aggregates (1), isolated biomineral nanoparticles (2), cytoplasm dispersed ferritin cores (3), and spleen hemosiderin aggregates (4). Small insets from center and right TEM images are at the same magnification, showing the smaller particle size observed in hippocampus (2) in comparison with the spleen ferritin cores (3). (D) In the hippocampus and spleen of Pfn2^−/−mice, electron-dense areas have been tested by EDS to confirm the presence of iron. **P ≤ .01.