Modeling bone marrow microenvironment and hematopoietic dysregulation in Gaucher disease through VavCre mediated Gba deletion.

Abstract

Biallelic mutations in Gba cause Gaucher disease (GD), a lysosomal disorder characterized by deficient glucocerebrosidase activity and the accumulation of glucosylceramide (GlcCer) and glucosylsphingosine (GlcSph), primarily in macrophages. Beyond macrophages, GD pathology affects additional hematopoietic lineages, contributing to immune dysregulation. Existing Mx1-Cre Gba knockout models require induction protocols that lead to gene deletion outside hematopoietic cells, limiting the study of hematopoietic-specific effects. To overcome these limitations, we generated a hematopoietic-specific Gba knockout model by crossing Gbafl/fl mice with Vav-Cre, enabling early deletion of Gba exons 8-11 in hematopoietic stem and progenitor cells. These mice were backcrossed to 129X1/SvJ and C57BL/6 J backgrounds, revealing that genetic background significantly influences disease severity. Efficient Gba excision was confirmed in bone marrow, spleen, and thymus, with minimal recombination in the liver. In VavCre 129 GD mice, glucocerebrosidase activity in the spleen was severely reduced, leading to GlcCer and GlcSph accumulation and Gaucher cell infiltration in the spleen and femurs. Transcriptomic analysis identified upregulation of inflammatory and lysosomal pathways. Immune cell deconvolution from RNA-seq data further revealed an expansion of monocytes, dendritic cells, and pro-inflammatory macrophage subsets, suggesting an altered immune landscape. Additionally, GPNMB, a potential GD biomarker, was significantly elevated in both spleens and sera of VavCre 129 GD mice. This hematopoietic-specific GD model provides a powerful platform for studying GD pathophysiology, modifier genes, and immune dysregulation. It offers new opportunities for biomarker discovery and for developing strategies targeting hematopoietic and immune mechanisms in GD and related lysosomal storage disorders.