Beyond the Macrophage: System-wide Cellular and Molecular Dysregulation in GBA1 Deficient Mice Recapitulates Human Non-neuronopathic, Type 1 Gaucher Disease

In non-neuronopathic type 1 Gaucher disease (GD1) mutations in GBA1 gene results in deficiency of glucocerebrosidase and the accumulation of glucocerebroside in lysosomes of mononuclear phagocytes. The metabolic defect leads to a complex phenotype involving the viscera, the bone marrow and the skeleton. However the prevailing macrophage-centric view of the disease does not explain emerging aspects of the disease such as hematological malignancies, autoimmune diathesis, Parkinsons disease and osteoporosis poorly responsive to macrophage targeted enzyme therapy or anti-resorptive therapies. We developed a conditional KO mouse model of GD1 to delineate cells and pathways in GD1. By targeting the cells of the hematopoetic and mesenchymal cell lineages through an Mx1 promoter, we recapitulated human GD1. We show that, in addition to significant visceral and hematologic disease, GD1 mice show profound osteopenia due to a bone formation defect. Cytokine measurements, microarray analysis and cellular immunophenotyping together point to widespread dysfunction of macrophages and other immune cells together with a striking abnormality in thymic T-cell development. Our study provides the first direct evidence for the involvement of cell lineages other than mononuclear phagocytes, most notably osteoblasts and T cells, in the pathophysiology of the clinical spectrum of type 1 GD. These findings have important implications for treatment of GD1.

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Mistry PK, Liu J, Yang M, Nottoli T, McGrath J, Jain D, Zhang K, Keutzer J, Chuang WL, Mehal WZ, Zhao H, Lin A, Mane S, Liu X, Peng YZ, Li JH, Agrawal M, Zhu LL, Blair HC, Robinson LJ, Iqbal J, Sun L, Zaidi M