Inheritance of Lysosomal Acid β-Galactosidase Activity and Gangliosides in Crosses of DBA/2J and Knockout Mice

Abstract

GM1 gangliosidosis is a progressive neurodegenerative disease caused by deficiencies in lysosomal acid beta-galactosidase (beta-gal) and involves accumulation and storage of ganglioside GM1 and its asialo form (GA1) in brain and visceral tissues. Similar to the infantile/juvenile human disease forms, B6/129Sv beta-gal knockout (ko) mice express residual tissue beta-gal activity and significant elevations of brain GM1, GA1, and total gangliosides. Previous studies suggested that inbred DBA/2J (D2) mice may model a mild form of the human disease since total brain ganglioside and GM1 concentration is higher while beta-gal specific activity is lower (by 70-80%) in D2 mice than in inbred C57BL/6J (B6) mice and other mouse strains. A developmental genetic analysis was conducted to determine if the genes encoding beta-gal (Bgl) in the D2 and the ko mice were functionally allelic and if the reduced brain beta-gal activity in D2 mice could account for elevations in total brain gangliosides and GM1. Crosses were made between D2 mice homozygous for the Bgld allele (d/d), and either B6/129Sv mice heterozygous for the Bgl+ allele (+/-) or homozygous for the ko Bgl- allele (-/-) to generate d/+ and d/- mice. Specific beta-gal activity (nmol/mg protein/h) showed additive inheritance in brain, liver, and kidney at juvenile (21 days) and adult (255 days) ages with the d/- mice having only about 16% of the beta-gal activity as that in the +/+ mice. These results indicate that the Bgl genes in the D2 and the ko mice are noncomplementing functional alleles. However, the d/- mice did not express GA1 and had total brain ganglioside and GM1 concentrations similar to those in the d/+ and +/+ mice. These results suggest that the reduced brain beta-gal activity alone cannot account for the elevation of total brain gangliosides and GM1 in the D2 mice.

Bis(monoacylglycero)phosphate: a secondary storage lipid in the gangliosidoses

“…An aliquot was taken from the ganglioside fraction for sialic acid determination and sialic acid was quantifi ed by resorcinol assay. Gangliosides were further purifi ed with base treatment and desalting, as previously described ( 12,13,45 ). Treatment of gangliosides with mild base is needed to remove contaminating phospholipids and any ganglioside internal esters or salt forms that might arise as artifacts of the lipid isolation procedures ( 48,49 ).…”

“…Homozygous ( Ϫ / Ϫ ) mouse pups were derived from crossing heterozygous females with heterozygous male mice. Genotypes were determined as described previously ( 31,32 ). Cortex brain samples were collected at humane end point and stored at Ϫ 80°C.…”

Glycolipid and ganglioside metabolism imbalances in Huntington's disease

“…Total lipids were isolated and purified from lyophilized brain tissue by using modifications of previously described procedures (Seyfried et al, 1978a, Seyfried et al, 1978b, Hauser et al, 2004, Kasperzyk et al, 2005, Denny et al, 2006. Neutral and acidic lipids were separated by using DEAE-Sephadex (A-25; Pharmacia Biotech, Upsala, Sweden) column chromatography as previously described (Macala et al, 1983, Kasperzyk et al, 2005.…”

126. Comparative Analysis of brain lipids in Mice, Cats, and Humans with Sandhoff disease

“…Hexb −/− mice were derived from crosses of Hexb +/− females with Hexb −/− males. Genotypes of mice were determined by measuring the specific activity of total hexosaminidase using a modification of the Galjaard procedure as previously described (23,24). Hexb +/− and Hexb −/− mice were propagated in the Boston College Animal Facility and were housed in plastic cages with filter tops containing Sani-Chip bedding (P.J.…”

“…The amount of sialic acid in the ganglioside fraction was determined by the resorcinol assay and then the ganglioside fraction was further purified with base treatment and desalting, as previously described (24,26).…”