mDia1 cooperates with mDia2 to regulate HSPC functions and hematopoiesis under a steady state and during stress.

(A) Chimerism study of the peripheral blood from CD45.1+ recipient mice transplanted with BMMCs (2x106) from either double wild type (DWT), mDia1-/- (mDia1 KO), mDia2fl/fl Mx-Cre or mDia1-/-/mDia2fl/fl Mx-Cre (DKO Mx-Cre) mice before pIpC treatment. An equal number of BMMCs from wild-type CD45.1+ mice were used as competitors. The mice were treated with pIpC one month after transplantation. (B) Kaplan-Meier survival curve of the indicated mice. (C) Growth curve of the survived mice in B. (D) Reduction of white blood cell, red blood cell, and lymphocyte counts in DKO Vav-Cre mice. Peripheral blood was obtained from one-month-old indicated mice. DKO Vav-Cre offspring were pooled from 5–10 breeding cohorts. (E) Representative pictures showing reduced body size (upper) and severe anemia as indicated by pale forelimb in DKO Vav-Cre newborns on P8 (lower). (F) Wright-Giemsa stains of the peripheral blood smear from neonates in D. (G-I) Flow cytometric analysis and quantification of HSPCs (LSK) (G), common lymphoid progenitors (CLP) (H), and megakaryocytes-erythroid progenitors (MEP) (I) in infant mice. Data are presented as relative numbers to wild-type control mice. (J) Kaplan-Meier survival curve of indicated recipient mice receiving 5x105 donor BMMCs from neonatal mice in G. Error bars represent the SEM of the mean. * ppppp values were generated by a two-tailed unpaired student’s t-test, except the p-value in J was analyzed by the Mantel-Cox log-rank test.