Ultrastructure and immunocytochemistry of hepatic peroxisomes in rhizomelic chondrodysplasia punctata

Abstract

Peroxisomes were studied in the liver of two rhizomelic chondrodysplasia punctata patients using electron microscopy and catalase cytochemistry. Immunoelectron microscopy was carried out on the liver of one of these patients using antibodies to catalase, acyl-CoA oxidase, bifunctional protein, 3-ketoacyl-CoA thiolase and a 68 kDa peroxisomal membrane protein, in conjunction with protein-A colloidal gold. Moderately to markedly enlarged, flocculent peroxisomes were found in both patients. In one patient they were very heterogeneous with regard to the number per hepatocyte. The peroxisomes had very low levels of catalase as indicated by cytochemistry and immunocytochemistry. The three beta-oxidation enzymes were localised normally within the peroxisomes. The 68 kDa membrane protein was localised to the peroxisomal membranes. Some extra membrane loops were also identified using this antibody.

Human peroxisomal disorders

“…Peroxisomal thiolase localisation in RCDP: using immunopurified anti-thiolase antibodies from Hashimoto (1982), we found thiolase antigen inside enlarged hepatic Px of a typical RCDP patient , and of the atypical case of Smeitink et al (1992) (Espeel et al, 1993b). This is at variance with the current belief that in RCDP thiolase is not imported (Gould et al, 2001) because the receptor of the PTS2 sequence (Pex 7protein) is defective, but in agreement with Hughes et al (1992) in 1 patient. We propose that thiolase could make use of the PTS1 receptor, as is the case in C. elegans (Motley et al, 2000).…”

“…Hughes et al (1990Hughes et al ( , 1992) also measured enlarged Px in 2 RCDP, and in 2 mild Zellweger-like patients.…”

Biogenesis of peroxisomes in fetal liver

“…Thus, the typical feature of enlarged peroxisomes in the postnatal liver associated with these syndromes Heymans et al, 1986;Hughes et al, 1992;Poll-The et al, 1988) is already observed in the fetal liver. For a discussion on enlarged hepatic peroxisomes in peroxisomal disorder patients, see Roels (1991).…”

Pex13 Inactivation in the Mouse Disrupts Peroxisome Biogenesis and Leads to a Zellweger Syndrome Phenotype

“…Ultrathin sections (approximately 50 to 100 nm thick) were treated with 1% aqueous uranyl acetate and Reynold's lead citrate for contrast and viewed using a JEOL 1200EX electron microscope operating at 80 kV. For catalase cytochemistry, liver slices were fixed for 2 h at 4°C in 0.1 M sodium cacodylate buffer (pH 7.3) (19,20) containing 4% formaldehyde and 1% glutaraldehyde, incubated at 25°C for 1 h in Teorell & Stenhagen buffer (pH 10.5) (11) containing 3,3Ј-diaminobenzidine (DAB) tetrahydrochloride (2 mg/ ml) (Sigma Chemicals, St. Louis, Mo.) and 0.05% H 2 O 2 , and washed in 0.1 M sodium cacodylate buffer (pH 7.3).…”