BM hypoplasia and stem cell impairment in agrin-deficient (Musk-L;Agrn^−/−) mice. (A) Representative flow cytometric analysis of the LSK population for control and Musk-L;Agrn^−/− mice and mean numbers relative to controls are shown. Dot plots correspond to the Lin⁻/IL7R⁻ gate and the indicated values represent the percentage among total BM cells (ctrl, n = 26; Musk-L;Agrn^−/−, n = 11; *P < .05). (B) Representative flow cytometric analysis on LSK population: the analysis of CD150 versus CD41/48 expression and the analysis of CD135 versus CD34 expression were done on the Lin⁻IL7R⁻c-Kit⁺Sca-1⁺ population; the indicated values represent the percentage among total LSK cells. Pie charts represent average frequencies of the 3 subsets within LSK population (ctrl, n = 6; Musk-L;Agrn^−/−, n = 4;). CD150⁺CD41/48⁻ LSK and CD34⁺CD135⁻ LSK population frequencies are statistically different (P < .05). (C) Annexin V (top row) and cleaved caspase-3 (bottom row) analysis on CD34⁺CD135⁻ LSK cells. Left, representative flow cytometry profiles; right, statistical analysis (annexin: ctrl, n = 6; Musk-L;Agrn^−/−, n = 4; cleaved caspase-3: ctrl, n = 5; Musk-L;Agrn^−/−, n = 3; **P < .01). (D) Mean numbers relative to controls of the hematopoietic progenitors for control and Musk-L;Agrn^−/− mice are shown. CMPs are defined as Lin⁻IL7R⁻Sca-1⁻c-Kit⁺CD34⁺CD16/32^low, GMPs as Lin⁻IL7R⁻Sca-1⁻c-Kit⁺ CD34⁺CD16/3²⁺, MEPs as Lin⁻IL7R⁻Sca-1⁻c-Kit⁺CD34⁻CD16/32⁻, and CLPs are defined as Lin⁻IL7R⁺Sca-1^loc-Kit⁺ (ctrl, n = 15; Musk-L;Agrn^−/−, n = 8; *P < .05). In all panels, error bars represent SEM.