Biomedical subjects

Gouri Yogalingam

Publications and source records attributed to Gouri Yogalingam.

6 recordsLinked to original sources

PubMed2005

Short-term, high dose enzyme replacement therapy in sialidosis mice.

Given the success of enzyme replacement therapy (ERT) in treating the systemic manifestations in a number of lysosomal storage disorders (LSDs), we evaluated the effect of ERT on the mouse model of sialidosis. This glycoproteinosis, which affects primarily the reticuloendothelial (RE) system, is caused by deficiency of lysosomal neuraminidase (NEU1) and consequent accumulation of sialylated glycoconjugates. NEU1 lacks a functional mannose-6-phosphate recognition marker and is not endocytosed by mammalian cells. However, the enzyme produced in insect cells has features that allow its effective uptake by RE cells and macrophages via the mannose receptor, and therefore represent an alternative method of therapy. In this study we tested the therapeutic efficacy of baculovirus (BV) expressed mouse neuraminidase (Neu1) in sialidosis mice. Four-week-old Neu1-/- mice were first injected intravenously with a single dose of the recombinant enzyme for assessment of the half-life of mannosylated Neu1 in vivo. Afterwards, a short-term ERT with a total of five enzyme injections over a 2-week period was performed for evaluation of phenotype correction. Neu1 infused alone or co-administered with its associated protein, protective protein/cathepsin A (PPCA) was effectively taken up by resident macrophages in many tissues. Restored Neu1 activity persisted for up to 4 days, depending on the tissue, and resulted in a significant reduction of lysosomal storage. However, beyond 2 weeks of treatment, ERT mice developed a severe immune response towards the exogenous Neu1 enzyme. These results may have important implications for ERT in sialidosis patients.

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PubMed2004

Targeting macrophages with baculovirus-produced lysosomal enzymes: implications for enzyme replacement therapy of the glycoprotein storage disorder galactosialidosis.

Lysosomal storage diseases (LSDs) are monogenic disorders of metabolism caused by deficiency of hydrolytic enzymes. In several LSDs, cells of the reticuloendothelial (RE) system are the primary targets of the disease. Exogenous administration of recombinant enzymes overproduced in mammalian cells has proved effective for treating the systemic phenotype in nonneuropathic patients with LSDs. However, for the treatment of diseases with primary involvement of the RE system, the production of the therapeutic enzyme in insect cells could be an alternative and advantageous method because glycoproteins expressed in insect cells carry carbohydrates of the pauci-mannose or core-type. These recombinant enzymes are in principle already poised to be internalized by cells that express mannose receptors, including macrophages. Here, we demonstrate that three baculovirus-expressed enzymes, protective protein/cathepsin A (PPCA), neuraminidase (Neu1), and beta-glucosidase, were readily taken up and restored lysosomal function in enzyme-deficient mouse macrophages. The capacity of recombinant PPCA and Neu1 to clear the lysosomal storage in target cells was assessed in PPCA-/- mice, a model of galactosialidosis. Intravenously injected PPCA-/- mice efficiently internalized the corrective enzymes in resident macrophages of many organs. In addition, treated mice showed overall clearance of lysosomal storage in the most affected systemic organs, kidney, liver, and spleen. Our results suggest that ERT with baculovirus-expressed enzymes might be an effective treatment for nonneuropathic patients with galactosialidosis and possibly for others with LSDs that primarily involve the RE system.

Animals↗

PubMed2004

Aryplase (Biomarin).

BioMarin is developing Aryplase (BM-102), a recombinant form of the enzyme N-acetylgalactosamine 4-sulfatase, for the potential treatment of mucopolysaccharidosis type VI (Maroteaux-Lamy Syndrome). By November 2003 enrollment for a pivoltal phase III trial was complete.

Animals↗

PubMed2003

Molecular cloning of feline CD34.

In humans, baboons, dogs and mice CD34 is a cell surface molecule that is expressed on primitive hematopoietic cells and in all these species CD34 positive cells can be used to effect long-term haematopoietic reconstitution. CD34 positive haematopoietic cells therefore provide a convenient and relatively small cell population to target when attempting gene therapy via the haematopoietic system. In order to develop the mucopolysaccharidosis type VI (MPS VI) cat as a model for haematopoietic cell-mediated gene therapy we have isolated the feline CD34 gene as a first step in the generation of antibodies for purification of feline CD34 positive cells. The coding sequence for feline CD34 was isolated from brain cDNA using the polymerase chain reaction (PCR) with oligonucleotides designed to conserved regions of known CD34 gene sequences as primers. Sequence analysis of PCR products revealed the complete amino acid sequence of feline CD34 and allowed analysis of sequence conservation with CD34 from other species. Northern blot analysis showed a 2.6 kb CD34 transcript was present in feline brain, spleen, heart, testis and thymus, and to a lesser extent, in liver. A full-length cDNA clone of the feline CD34 coding sequence was assembled and expressed in CHO-K1 cells. The isolation and expression of the feline CD34 cDNA should facilitate the production of antibodies suitable for the purification of CD34 positive cells.

Amino Acid Sequence↗

PubMed2003

Identification and characterization of 13 new mutations in mucopolysaccharidosis type I patients.

In this study we have investigated a group of 29 Brazilian patients, who had been diagnosed with the lysosomal storage disorder, Mucopolysaccharidosis type I (MPS-I). MPS I is caused by a deficiency in the lysosomal hydrolase, alpha-L-iduronidase. Ninety percent of the MPS I patients in this study were genotyped and revealed 10 recurrent and thirteen novel IDUA gene mutations. Eight of these new mutations and three common mutations W402X, P533R, and R383H were individually expressed in CHO-K1 cells and analyzed for alpha-L-iduronidase protein and enzyme activity. A correlation was observed between the MPS I patient clinical phenotype and the associated mutant alpha-L-iduronidase protein/enzyme activity expressed in CHO-K1 cells. This was the first time that Brazilian MPS I patients had been thoroughly analyzed and highlighted the difficulties of mutation screening and clinical phenotype assessment in populations with high numbers of unique mutations.

Animals↗

PubMed2002

Identification of a mutation causing mucopolysaccharidosis type IIIA in New Zealand Huntaway dogs.

Mucopolysaccharidosis type IIIA (MPS IIIA) is an autosomal recessive disease that occurs due to a deficiency of heparan sulfate sulfamidase (SGSH). The deficiency of SGSH results in the lysosomal accumulation and urinary excretion of the glycosaminoglycan heparan sulfate. The clinical severity of MPS IIIA is predominantly characterized by severe central nervous system degeneration. Naturally occurring MPS IIIA has recently been described in New Zealand Huntaway dogs, with similar disease progression and biochemical characteristics observed in severely affected MPS IIIA patients. Here, we identify the disease-causing mutation in the MPS IIIA Huntaway dog as 708-709insC. The frequency of the 708-709insC mutation in a sample group of 203 New Zealand Huntaway dogs was determined to be 3.8%. The identification of the 708-709insC mutation will permit the identification of heterozygous carriers as an initial step toward establishing a breeding colony of MPS IIIA dogs for the study of various therapeutic strategies targeted to the central nervous system.

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