Figure 6.
Transcriptome analysis of individually isolated cochlear Dio2+ cell types. A, Heatmap of representative, differentially expressed genes identifying major osteoblast and fibrocyte groups in single cell datasets from mice heterozygous for the Dio2CreERt2 allele (Dio2CreERt2;Ai6). Tamoxifen was given at P3/P4 and cells analyzed at P10. A few cells (7/46) lacked consistent osteoblast or fibrocyte markers and may represent less-differentiated mesenchyme-derived cell types based on early markers (eg, Pou3f4). Four macrophages were identified. Data shown as log2 (CPM + 1). B, Candidate membrane transporters for thyroid hormone. Most fibrocytes express Slco1c1 and often Slc16a2 and Slco1a4; osteoblasts most consistently express Slco3a1. Most cells lacked Dio3 or Dio1 but expressed some level of Dio2, as expected. C, Gene ontology analysis of selected top categories for osteoblast and fibrocyte groups. D, Aif1 (Iba1) staining (magenta) shows macrophages in a dispersed pattern over most cochlear tissues compared with the restricted pattern of Dio2+ cells (pale blue) (D). E, Rare double-positive cell (arrowhead) in the spiral ligament (area “e” in panel D). In Aif1 + cells, Dio2CreERt2;Ai6 signal tended to clump rather than fill the cell. DAPI (dark blue), general nuclear stain.