Gene expression of steroid biosynthetic enzymes in murine DCs and their progenitors. (A, top) Steroid biosynthetic pathway is shown for generation of corticosterone (“B”) from cholesterol or from 11-dehydrocorticosterone (“A”). Individual steps in biosynthesis are catalyzed by enzymes shown: P450, cholesterol side chain–cleaving enzyme; 3βHSD, 3β-hydroxysteroid dehydrogenase; P450c21, 21-hydroxylase; P450c11, 11β-hydroxylase; 11βHSD1; and H6PDH. (A, bottom) Heat map showing expression of corresponding genes (in order from top to bottom) from (1) lymphoid tissue DCs: CD8α⁺CD11b^– DCs derived from spleen and lymph nodes, thymic CD8α⁺ DCs, and CD8α^–CD11b⁺ DCs derived from spleen and lymph nodes; (2) migratory DCs: CD103⁺CD11b^–, CD103^–CD11b⁺, Langerhans cells (LCs) from draining lymph nodes, and pDCs from spleen and lymph nodes; (3) nonlymphoid tissue DCs: lung CD103⁺CD11b^– DCs with or without prior polyinosinic:polycytidylic acid (poly I:C) treatment in vivo; liver and small intestinal (SI) CD103⁺CD11b^– DCs; lung, liver, SI, and kidney CD103^–CD11b⁺ DCs; SI CD103⁺CD11b⁺ DCs; and LCs within epidermis; (4) myeloid progenitors: GMP, granulocyte-macrophage progenitor; MDP, macrophage-dendritic cell progenitor; and CDP, common dendritic cell progenitor; and (5) monocytes (Mo) and macrophages (Mac). Methods and selection markers used to isolate individual subsets are available from the Immunological Gene Project.²⁴  (B) Scatter plots showing gene expression (mean centered log₂ expression units) in relation to the mean of the whole data set for individual steroid biosynthetic genes. Values in bottom right corner of each plot show the coefficient of determination (R²) for each x-y comparison. (C) Graph showing mean centered relative expression of H6pd and Hsd11b1 in whole data set (light gray), with expressions highlighted in color for pDC (green squares), CD8α⁺ DC (red upward triangles) and CD8α^– DC (blue downward triangles) subsets. (D) Graphs showing H6pd and Hsd11b1 messenger RNA (mRNA) expression as evaluated by quantitative reverse-transcription polymerase chain reaction in CD8α^– DCs (n = 3 to 4) and pDCs (n = 3 to 6), relative to CD8α⁺ DCs (n = 3 to 4). P value represents comparison of pDCs to each of the other subsets.