Figure 7. Endothelial Hippo signaling promotes coupling of angiogenesis and osteogenesis.

(A) Average body weight of P21 control and Yap1/Taz^iΔEC mutants (n = 6; data are presented as mean ±sem, P values, two-tailed unpaired t-test). (B, C) Representative images of P21 control and Yap1/Taz^iΔEC femur (C). Quantitation of femur length and weight show no changes between Yap1/Taz^iΔEC mutants and littermate controls (C) (n = 6; data are presented as mean ±sem, P values, two-tailed unpaired t-test). (D) Confocal images showing Osterix+ cells (green) in relation to Emcn+ ECs (red) in P21 Yap1/Taz^iΔEC and control metaphysis. Graph on the right shows quantitative analysis of Osterix+ (Osx+) cells (control n = 6 and Yap1/Taz^iΔECn = 6; data are presented as mean ±sem, P values, two-tailed unpaired t-test). (E) Confocal images showing bone vessels (Emcn), and the bone matrix protein Osteopontin in Yap1/Taz^iΔEC vs control femur. (F) Representative confocal images of Osterix+ cells (green) in relation to Emcn+ ECs (red) in the P21 control and Yap1-KI^iEC femoral metaphysis. Graph on the right shows significant reduction of Osterix+ cells in Yap1-KI^iEC mutants (n = 6; data are presented as mean ±sem, P values, two-tailed unpaired t-test). (G) Decreased bone matrix protein Osteopontin (Opn, green) deposition in P21 Yap1-KI^iEC femur relative to control. ECs, Emcn (red). (H, I) Representative μCT images of trabecular bone in P21 control and Yap1/Taz^iΔEC femur (H). Quantitative analysis of trabecular volume (BV/TV, bone volume/total volume) trabecular (Tb.) number, Tb. thickness, and Tb. separation (I). (n = 5; data are presented as mean ±sem, P values, two-tailed unpaired t-test).

Figure 7—figure supplement 1. Endothelial Yap1/Taz controls coupling of angiogenesis and osteogenesis.

(A) Quantifications of tibia weight and length show no changes between Yap1/Taz^iΔEC mutants and littermate controls (n = 6; data are presented as mean ±sem, P values, two-tailed unpaired t-test). (B) Confocal images showing osteoblast markers collagen type aI (Col type I, alpha 1) and Osteocalcin (Ocn), osteoprogenitor differentiation marker Runx2 and the osteoclast marker ATP6V1B1 and two in Yap1/Taz^iΔEC and control femur. (C–E) Average body weight of control and Yap1-KI ^iEC mice (C). Representative images of P21 control and Yap1-KI ^iEC femur (D). Quantification of femur and tibia weight and length in Yap1-KI ^iEC mutants relative to littermate controls (E) (n = 4, 5; data are presented as mean ±sem, P values, two-tailed unpaired t-test). (F) Representative confocal images of Osterix+ cells (red) in relation to Emcn+ ECs (blue) in P21 control, Yap1/Taz^iΔEC and Yap1/Taz; Hif-1a^iΔEC femoral metaphysis. Quantification of Osterix+ cells in Yap1/Taz^iΔEC and Yap1/Taz; Hif-1a^iΔEC mutants compared to control (n = 6; data are presented as mean ±sem, P values, two-tailed unpaired t-test).