Differential expression of peroxisomal matrix and membrane proteins during postnatal development of mouse brain

Abstract

In peroxisomal biogenesis disorders, serious neurological abnormalities can be observed in the patients and the respective knockout mouse models. As a prerequisite for a better understanding of the relationship between the absence of peroxisomes and the observed neuropathology, knowledge of the regional and cell-type specific distribution of peroxisomal proteins in mouse brain is necessary. Therefore, we investigated the expression of distinct peroxins, peroxisomal membrane and matrix proteins (e.g. Pex5p, Pex14p, Pex13p, PMP70, catalase, peroxisomal thiolase, Acox1, "SKL"-PTS1 proteins) by indirect immunofluorescence 1) in primary cultures of the medial neocortex, hippocampus, and cerebellum of newborn mice and 2) in paraffin sections of mouse brain of different ages (newborn-adult). Quantitative analysis revealed a comparable abundance (number/microm(2)) of peroxisomes in cultured neurons and astrocytes of all three brain regions. In contrast, catalase immunoreactivity was higher in cultured astrocytes than in neurons. In mouse brain tissue, the abundance of peroxisomes decreased by half during postnatal development, also exhibiting prominent differences between distinct brain regions and cell types. Catalase protein levels in neuronal peroxisomes, however, decreased much more strongly in the neocortex, CA1-3 areas of the hippocampus, dentate gyrus, cerebellar nuclei, and cerebellar cortex but remained high in Bergmann glia and other astrocytes, epithelial cells of the choroid plexus, and ependyma. Similar age-dependent changes were found for thiolase and Acox1 protein levels. Developmental changes were confirmed by Western blot analysis using enriched peroxisomal and cytosolic fractions of the brain tissue as well as by measurement of catalase activity.

Lipid Metabolism Impairment in Human Gliomas: Expression of Peroxisomal Proteins in Human Gliomas at Different Grades of Malignancy

“…2-4). Densitometric analysis of the immunoreactive staining of PEX 14p, marker of peroxisomal number (27), confirmed these data, indicating that the peroxisomes are significantly upregulated in higher grade gliomas (Fig. 2).…”

Compromised peroxisomes in idiopathic pulmonary fibrosis, a vicious cycle inducing a higher fibrotic response via TGF-β signaling

“…DHE is oxidized by superoxide to its fluorescent product, ethidine. Ethidine remains intracellularly after it is oxidized, thus allowing quantitative estimations of the intracellular ROS level (40). See SI Materials and Methods.…”

Peroxisomes in mouse and human lung: their involvement in pulmonary lipid metabolism

“…For staining of peroxisomes, several antibodies against (a) peroxisomal membrane proteins, e.g., rabbit anti-biogenesis proteins Pex13p and Pex14p (Maxwell et al 2003) and the ABC-transporter D3 (ABCD3/PMP70) (Fang et al 2004;Islinger et al 2006) and (b) peroxisomal matrix proteins such as rabbit anti-catalase (Maxwell et al 2003), acyl-CoA oxidase 1 (Huyghe et al 2001), and peroxisomal 3-oxo-acyl-CoA thiolase (Antonenkov et al 1999) were used. Most antibodies against peroxisomal proteins were already tested for speciWcity in immunoXuorescence preparations of paraYn sections of other tissues (brain, Ahlemeyer et al 2007; testis, Nenicu et al 2007). The antibodies were kind gifts from Profs.…”