Bowles, K. R. | Search bioRxiv

bioRxiv2020

Cell-type specific gene expression profiling in heterogeneous in vitro cultures using epitope-tagged RPL22

Genetic and genomic studies of brain disease increasingly demonstrate disease-associated interactions between the cell types of the brain. Increasingly complex and more physiologically relevant human induced pluripotent stem cell (hiPSC)-based models better explore the molecular mechanisms underlying disease, but also challenge our ability to resolve cell-type specific perturbations. Here we report an extension of the RiboTag system, first developed to achieve cell-type restricted expression of epitope-tagged ribosomal protein (RPL22) in mouse tissue, to a variety of in vitro applications, including immortalized cell lines, primary mouse astrocytes, and hiPSC-derived neurons. RiboTag expression enables efficient depletion of off-target RNA in mixed species primary co-cultures and in hiPSC-derived neural progenitor cells, motor neurons, and GABAergic neurons. Nonetheless, depletion efficiency varies across independent experimental replicates. The challenges and potential of implementing RiboTags in complex in vitro cultures are discussed.

molecular biology↗

bioRxiv2019

17q21.31 sub-haplotypes underlying H1-associated risk for Parkinson's disease and progressive supranuclear palsy converge on altered glial regulation

Parkinsons disease (PD) is genetically associated with the H1 haplotype of the MAPT 17q.21.31 locus, although the causal gene and variants underlying this association have not been identified. To better understand the genetic contribution of this region to PD, we fine-mapped the 17q21.31 locus in order to identify novel mechanisms conferring risk for the disease. We identified three novel H1 sub-haplotype blocks across the 17q21.31 locus associated with PD risk. Protective sub-haplotypes were associated with increased LRRC37A/2 copy number and expression in human brain tissue. We found that LRRC37A/2 is a membrane-associated protein that plays a role in cellular migration, chemotaxis and astroglial inflammation. In human substantia nigra, LRRC37A/2 was primarily expressed in astrocytes, interacted directly with soluble -synuclein, and co-localized with Lewy bodies in PD brain tissue. These data indicate that a novel candidate gene, LRRC37A/2, contributes to the association between the 17q21.31 locus and PD via its interaction with -synuclein and its effects on astrocytic function and inflammatory response. These data are the first to associate the genetic association at the 17q21.31 locus with PD pathology, and highlight the importance of variation at the 17q21.31 locus in the regulation of multiple genes other than MAPT and KANSL1, as well as its relevance to non-neuronal cell types.

neuroscience↗