Journal: bioRxiv

Article Title: Macrophages regulate meiotic initiation and germ cell clearance in the developing ovary

doi: 10.64898/2026.02.28.708733

Figure Lengend Snippet: (a) Representative whole-mount images of E13.5 ovaries from C57BL/6J embryos exposed at E6.5 to either control rat IgG2a antibody or anti-CSF1R blocking antibody to deplete YS-derived macrophages. For F4/80, PECAM1, and FOXL2 staining, n =5 control and n =6 anti-CSF1R-treated independent gonads; for CD11b and CD45 staining, n =3 control and n =3 anti-CSF1R-treated independent gonads. Insets show higher-magnification views of boxed regions; dashed lines mark the gonad-mesonephros boundary. (b) qRT-PCR analysis of macrophage-associated genes ( Adgre1, Cx3cr1, Csf1r, Mrc1 ) and endothelial marker Cdh5 , showing fold change in gene expression in E13.5 anti-CSF1R-treated ovaries versus controls. (c) Representative E14.5 sections stained for SYCP3 and TRA98 showing increased meiotic germ cells in anti-CSF1R-treated ovaries ( n =4) compared with control ovaries ( n =4). (d) qRT-PCR analysis of germ cell and meiotic genes ( Kit, Pou5f1, Ddx4, Stra8, Sycp1, Sycp3, Syce1, Smc1b ), showing fold change in gene expression in E14.5 anti-CSF1R-treated ovaries versus controls. (e) Representative E18.5 sections stained for F4/80 and CD45, and for SYCP3 and FOXL2, showing recovery of F4/80⁺ macrophages and advanced meiotic progression in anti-CSF1R-treated ovaries compared with control ovaries. For F4/80 and CD45 staining, n =4 control and n =4 anti-CSF1R-treated independent gonads; for SYCP3 and FOXL2 staining, n =3 control and n =3 anti-CSF1R-treated independent gonads. Arrows indicate SYCP3⁺ dictyate-stage oocytes. (f) Percentage of SYCP3⁺ germ cells at the dictyate stage among total SYCP3⁺ cells at E18.5. Data are shown as mean +/− SD. * P <0.05, ** P <0.01, *** P <0.001 (two-tailed Student’s t -tests). Scale bars, 100 μm (overview) and 50 μm (higher magnification/insets).

Article Snippet: To transiently deplete yolk-sac-derived and fetal CSF1R + macrophages, pregnant C57BL/6J females were injected intraperitoneally with 3 mg anti-CSF1R monoclonal antibody (mAb; clone AFS98, Bio X Cell #BP0213) or rat IgG2a isotype control (Bio X Cell #BP0089).

Techniques: Control, Blocking Assay, Derivative Assay, Staining, Quantitative RT-PCR, Marker, Gene Expression, Two Tailed Test

Journal: bioRxiv

Article Title: Macrophages regulate meiotic initiation and germ cell clearance in the developing ovary

doi: 10.64898/2026.02.28.708733

Figure Lengend Snippet: (a) Representative images of E18.5, P3, and P10 ovaries from C57BL/6J embryos exposed at E6.5 and E14.5 to either control rat IgG2a antibody or anti-CSF1R blocking antibody to deplete fetal ovarian macrophages. For E18.5, n =4 control and n =4 anti-CSF1R-treated independent gonads; for P3, n =6 control and n =6 anti-CSF1R-treated independent gonads; for P10, n =4 control and n =4 anti-CSF1R-treated independent gonads. Insets show higher-magnification views of boxed regions; red and green dashed outlines demarcate the ovary. (b) Representative sections stained for DDX4, showing developmental germ cell attrition at E18.5, P3, and P10 in control and anti-CSF1R-treated ovaries. For each time point, n =4 control and n =4 anti-CSF1R-treated independent gonads. (c) Quantification of CD45⁺IBA1 + macrophages per 0.1 mm² ovarian area at E18.5, P3, and P10. (d) Quantification of CD45⁺IBA1 − monocyte-like cells per 0.1 mm² ovarian area at the indicated stages. (e) Quantification of DDX4⁺ germ cell number per 0.1 mm² ovarian area at E18.5, P3, and P10, showing reduced physiological germ cell loss after macrophage depletion. Data are shown as mean +/− SD. * P <0.05, ** P <0.01, *** P <0.001 (two-tailed Student’s t -tests). Scale bars, 100 μm (overview) and 50 μm (higher magnification/insets).

Article Snippet: To transiently deplete yolk-sac-derived and fetal CSF1R + macrophages, pregnant C57BL/6J females were injected intraperitoneally with 3 mg anti-CSF1R monoclonal antibody (mAb; clone AFS98, Bio X Cell #BP0213) or rat IgG2a isotype control (Bio X Cell #BP0089).

Techniques: Control, Blocking Assay, Staining, Two Tailed Test