Research Grant Reviews 2004 In 2004 the National MPS Society awarded grants to Dr. Maria Pia Cosma for her work "Gene Therapy for MPS II" and to Dr. Mark Sands for his work, "Systemic inflammation associated with lysosomal storage diseases". Below are the reviews they submitted summarizing the second year of their research. "Systemic Inflammation Associated with Lysosomal Storage Diseases" Dr. Mark S. Sands, Washington University, St. Louis, MO The goal of this research was to determine the underlying cause of the anemia and adipose storage deficiency associated with MPS I and whether this phenotype was common to other lysosomal storage diseases (LSDs). We also proposed to determine if the systemic inflammation associated with MPS I was common to other LSDs and whether a reduction in the levels of certain pro-inflammatory molecules affected the disease progression. We initially showed that MPS I mice had a 41% decrease in body fat and an 18% decrease in hematocrit when compared to normal litter mates. The anemia was not a common finding among the other models of LSD. However, the inability to accumulate normal fat stores is common to other LSDs. Mouse models of MPS IIIB, MPS VII, Niemann-Pick AB (NPAB), and Infantile Neuronal Ceroid Lipofuscinosis (INCL) have 37, 51, 42, and 15% decreases in body fat, respectively, when compared to normal litter mates. We tested a number of simple hypotheses that might explain this decrease in fat stores. There was no significant difference in food intake, physical activity (open field test), metabolic rate (O2 consumption), fecal content (free fatty acids, triglycerides, cholesterol), serum content (free fatty acids, triglycerides, cholesterol), muscle triglycerides, or liver triglycerides between affected animals and normal controls. However, in the process of searching for the cause of the adipose storage deficiency, we discovered that the level of pro-inflammatory molecules (specifically chemokines) was significantly elevated in the MPS I mouse. We discovered similar changes in the other models of LSD. Interestingly, MCP-1, MCP-3 and soluble VCAM were elevated in the serum of every model we tested, and lymphotactin, M-CSF, MIP-1, and TIMP-1 were elevated in 3 out of 5 of the models. There is growing evidence that chemokines can have a direct effect on adipocytes and fat metabolism. We hypothesized that inhibition or genetic deletion of certain chemokines would affect, perhaps ameliorate the adipose deficiency associated with the models of LSD. We created a mouse model of MPS I that also expressed the pan chemokine-binding protein M3. M3 is a -herpes virus-encoded protein that binds and inactivates many chemokines. We also moved the MPS I and NPAB mutations onto a mouse model that is genetically deficient in MCP-1. We chose the knockout animal of MCP-1 since it is one of the chemokines that is elevated to the highest levels in every animal model of LSD. Neither the inhibition of the chemokines by M3 nor the genetic deletion of MCP-1 led to any increases in adiposity in either the MPS I or the NPAB mouse. Although our hypothesis that chronic inflammation associated with LSDs leads to adipose storage deficiency appears to be incorrect, these studies have enabled us to develop several additional hypotheses that could explain this phenotype. We are currently testing the hypotheses that either malabsorption or a change in the gut biota result in the adipose deficiency that is common to the mouse models of LSD. We believe that the adipose storage deficiency is an important clinical finding and correction of this phenotype might improve the quality of life of the affected children. "Gene Therapy for MPS II: Strengthening Iduronate Sulfatase Enzymatic Activity Through the Action of the Sulfatase Modifying Factor 1" Dr. Maria Pia Cosma, TIGEM, Naples, Italy Our results have been published in the following paper: Cardone M, Polito VA, Pepe S, Mann L, D'Azzo A, Auricchio A, Ballabio A and Cosma MP.(2006). Correction of Hunter syndrome in the MPS II mouse model by AAV2/8-mediated gene delivery. Human Mol Genet, April,15(7), 1225-36 Mucopolysaccharidosis type II (MPS II; Hunter syndrome) is a lysosomal storage disorder caused by a deficiency in the enzyme iduronate 2-sulfatase (IDS). At present, the therapeutic approaches for MPS II are enzyme replacement therapy and bone marrow transplantation, although these therapies have some limitations. The availability of new AAV serotypes that display tissue-specific tropism and promote sustained expression of transgenes offers the possibility of AAV-mediated gene therapy for the systemic treatment of lysosomal diseases, including MPS II. We have characterized in detail the phenotype of IDS-deficient mice, a model of human MPS II. These mice display a progressive accumulation of glycosaminoglycans (GAGs) in many organs and excessive excretion of these compounds in their urine. Furthermore, they develop skeleton deformities, particularly of the craniofacial bones, and alopecia, they perform poorly in open-field tests and they have a severely compromised walking pattern. In addition, they present neuropathological defects. We identified loss of Purkinje cells and cellular vacuolization in different regions of the brain: the hippocampus, thalamus, cerebellum and brainstem. We have designed an efficient gene therapy approach for the treatment of these MPS II mice. AAV2/8TBG-IDS viral particles were administrated intravenously to adult MPS II mice. The plasma and tissue IDS activities were completely restored in all of the treated mice. This rescue of the enzymatic activity resulted in the full clearance of the accumulated GAGs in all of the tissues analyzed, the normalization of the GAG levels in the urine and the correction of the skeleton malformations and of the locomotor disabilities. Furthermore a partial clearance of the GAG accumulation was also evident within the choroid plexus in the treated mice. This was surprising given the presence of the hemato-encephalic barrier. We predict that due to the very high levels of IDS in the plasma, which ranged from 16 to 70 times higher than the normal wild-type values, a fractional amount of the enzyme crossed the barrier and corrected the defect. Overall, our findings suggest that this in vivo gene transfer approach has potential for the systemic treatment of patients with Hunter syndrome.