Figure 6. Targeting YAP1 is sufficient... | American Society of Hematology

Figure 6.

$Targeting YAP1 is sufficient to rescue thrombopoiesis in YAP1+/− ITP mice and patients with ITP. (A) Comprehensive schematic overview of the YAP1 rescue mouse model. ckit+ HSCs were isolated from WT mice, and further conducted GATA1 knockdown HSCs using short hairpin RNA. Subsequently, BMT mouse models using GATA1 knockdown BM were established. Seven days after BMT, XMU-MP-1 was administrated once per day for the following 3 days. (B) Changes in the peripheral platelet levels in mice during BMT reconstruction (n ≥ 5). (C) Confocal images of BM sections from WT mice in groups after immunostaining for vascular sinusoids (yellow, laminin A) and MKs (red, CD41). Scale bar, 100 μm. Analysis of MK numbers (top) and the number of MKs located around the sinusoids (bottom; n ≥ 10). (D) The anti-CD41 antibody–induced ITP mouse model was established for 7 days, and XMU-MP-1 was administrated once per day for the following 3 days. Changes in peripheral platelet levels in mice during antibody administration and recovery (n ≥ 6). (E) Confocal images of BM sections from WT and YAP1+/− mice after immunostaining for YAP1 (green, YAP1), vascular sinusoids (yellow, laminin A), and MKs (red, CD41). Scale bar, 50 μm. Analysis of MK numbers (middle) and number of MKs located around the sinusoids (right; n ≥ 10). (F) Confocal images of spreading and cytoskeletal organization in MKs from WT and YAP1+/− mice in groups after immunostaining for YAP1 (green, YAP1), F-actin (yellow, phalloidin), and MKs (red, CD41). Scale bar, 10 μm. (G) XMU-MP-1 (300 nM for 24 hours) treatment facilitated proplatelet formation in MKs from patients with refractory ITP (ITP1) and chronic ITP (ITP2). (H) Proposed model. YAP1 regulates thrombopoiesis by binding to MYH9 in the context of ITP. ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001. G sh1, GATA1sh1; G sh2, GATA1sh2; sh, short hairpin; Sh1 X, GATA1sh1 + XMU; Sh2 X, GATA1sh2 + XMU; W, WT.$

Targeting YAP1 is sufficient to rescue thrombopoiesis in YAP1^+/− ITP mice and patients with ITP. (A) Comprehensive schematic overview of the YAP1 rescue mouse model. ckit⁺ HSCs were isolated from WT mice, and further conducted GATA1 knockdown HSCs using short hairpin RNA. Subsequently, BMT mouse models using GATA1 knockdown BM were established. Seven days after BMT, XMU-MP-1 was administrated once per day for the following 3 days. (B) Changes in the peripheral platelet levels in mice during BMT reconstruction (n ≥ 5). (C) Confocal images of BM sections from WT mice in groups after immunostaining for vascular sinusoids (yellow, laminin A) and MKs (red, CD41). Scale bar, 100 μm. Analysis of MK numbers (top) and the number of MKs located around the sinusoids (bottom; n ≥ 10). (D) The anti-CD41 antibody–induced ITP mouse model was established for 7 days, and XMU-MP-1 was administrated once per day for the following 3 days. Changes in peripheral platelet levels in mice during antibody administration and recovery (n ≥ 6). (E) Confocal images of BM sections from WT and YAP1^+/− mice after immunostaining for YAP1 (green, YAP1), vascular sinusoids (yellow, laminin A), and MKs (red, CD41). Scale bar, 50 μm. Analysis of MK numbers (middle) and number of MKs located around the sinusoids (right; n ≥ 10). (F) Confocal images of spreading and cytoskeletal organization in MKs from WT and YAP1^+/− mice in groups after immunostaining for YAP1 (green, YAP1), F-actin (yellow, phalloidin), and MKs (red, CD41). Scale bar, 10 μm. (G) XMU-MP-1 (300 nM for 24 hours) treatment facilitated proplatelet formation in MKs from patients with refractory ITP (ITP1) and chronic ITP (ITP2). (H) Proposed model. YAP1 regulates thrombopoiesis by binding to MYH9 in the context of ITP. ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001. G sh1, GATA1sh1; G sh2, GATA1sh2; sh, short hairpin; Sh1 X, GATA1sh1 + XMU; Sh2 X, GATA1sh2 + XMU; W, WT.

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