Peroxisome through cell differentiation and neoplasia

Abstract

Peroxisomes are essential in cellular metabolism as their dysgenesis or defects in single enzymes or impairment of multiple peroxisomal enzymatic functions have been found in several inherited metabolic diseases with serious clinical sequelae. The assembly and formation of these cytoplasmic organelles constitute a major and intriguing research topic. In the present study the biogenesis of peroxisomes and the developmental patterns of their enzymes have been reviewed during embryonic and/or post-embryonic ontogenesis of lower (amphibians) and higher (avians, mammals) vertebrates. In developing vertebrates, epithelial cell differentiation is accompanied by increases in frequency and size of peroxisomes. The tissue-specific expression of peroxisomal enzymes contributes substantially to the biochemical maturation of epithelial cells. The relationship between biogenesis of peroxisomes, expression of peroxisomal enzymes and structural and functional cellular phenotype has also been investigated in differentiating epithelial cells along the crypt-villus axis of the adult rat intestine. Cytochemical studies at the ultrastructural level have provided evidence that peroxisomes are already present in proliferating cells of the intestinal crypt region before they begin to differentiate. Migration and differentiation of intestinal epithelial cells from crypt to villus compartments are marked by significant increases in number and size of catalase-positive structures. Increasing activity gradients from crypt to surface areas are found for the peroxisomal oxidases examined (enzymes of the peroxisomal beta-oxidation system, D-amino acid oxidase and polyamine oxidase). Thus, peroxisomes are more and more involved in oxidative metabolic pathways as intestinal epithelial cells differentiate. Finally, we have analyzed the peroxisomal behaviour in human neoplastic epithelial cells. The presence of peroxisomes has been cytochemically revealed in human breast and colon carcinomas. Peroxisomal enzyme specific activities are significantly lower in human breast and colon carcinomas than in the adjacent healthy mucosa. Furthermore, a relationship is found between the specific activities of some peroxisomal enzymes and the histological tumour grades.

Hypoxia induces peroxisome proliferator-activated receptor α (PPARα) and lipid metabolism peroxisomal enzymes in human glioblastoma cells

“…The content and function of the enzymes within the peroxisome may vary in the different cell types. In environments with competing metabolic needs, the physiological needs of the cellular environment dictate the state of the peroxisome population and peroxisomal protein content (Keller et al, 1993(Keller et al, , 2000. In our previous study we have demonstrated that peroxisomal number and peroxisomal enzymes, mainly those related to lipid metabolism, are strongly upregulated in function of the glioma malignancy grade (Benedetti et al, 2010), in this study we evaluated the expression profiles of several peroxisomal proteins on primary cultures derived from patients affected by glioma at different grades of malignancy.…”

The Gallbladder ofUranoscopus ScaberL. (Teleost Perciform Fish) is Lined by Specialized Cholecystocytes

“…When their electron density is less opaque, one can also find a straight, twisted, or curved, narrow crystal of catalase (Baumgart et al, 1997). Their apical and near apical location is typical for the bile tract as the same kind of peroxisomes are always found associated with the apices of cells in developing and differentiated bile canaliculi (Keller et al, 1993), bile ducts and in the mammalian gallbladder epithelium (Depreter et al, 2002;Kojima et al, 2003); they are similarly located in the gallbladder of other fish species (Kramar et al, 1974;Ruiter et al, 1985Ruiter et al, , 1988. The peroxisome-mitochondria association is a metabolic requirement in all cells as the peroxisomes offer protection against oxidative species and assist in oxidations of long lipids, while the mitochondria are needed for the oxidative phosphorylation pathways and, in association with peroxisomes, to perform some b-oxidation and other metabolic functions while ''protecting'' the cells against toxic bile acids in this large gallbladder.…”

Mouse PeP: A novel peroxisomal protein linked to myoblast differentiation and development

“…Earlier studies had suggested that peroxisomes form a homogeneous population without further differences between organs or stages of development. Nevertheless, subsequent cytochemical and ultrastructural analyses showed that in vertebrates the peroxisome undergoes a process of maturation, increasing in size and number and gaining new capabilities along the embryonic development and early infancy (Keller et al, 1993).…”