Effects of bone marrow mesenchymal cells from immune thrombocytopenia patients on the biological behaviors of megakaryocytes / 上海交通大学学报（医学版）

ABSTRACT

Objective • To investigate changes of immune thrombocytopenia (ITP) patients-derived bone marrow mesenchymal cells (BMCs) in cells survival, cytokines expression as well as the effects of BMCs on the biological behaviors of megakaryocytes. Methods • BMCs were collected from 7 ITP patients and 5 normal controls (NC), and cultivated by the whole marrow adherent method. Surface markers and basal apoptosis rate of BMCs were analyzed by flow cytometry (FCM). Proliferation of BMCs was assessed by CCK-8 method. Phorbol 12-myristate 13-acetate (PMA) was used to stimulate differentiation of HEL cells. The induced HEL cells (inHEL) were divided into 3 groups: inHEL cultured alone (group a), inHEL co-cultured with BMCs derived from ITP patients (group b), inHEL co-cultured with BMCs derived from NC (group c). After 72 h incubation, the expression of cell surface proteins (CD41a, CD42b) and cell apoptosis rate were analyzed by FCM. The mRNA and proteins expression levels of cytokines IL6, IL11, TPO, SCF were detected by real-time fluorescent quantitative PCR (RT-qPCR) and enzyme linked immunosorbent assay (ELISA), respectively. Results • Compared with NC, BMCs from ITP patients grew progressively slowly (Day 4, P=0.039; Day 6, 10, P=0.009; Day 8, P=0.007), cell basal apoptosis rates were increased [AV+PI- (early apoptosis rate), P=0.036; AV+PI+ (late apoptosis rate), P=0.003; AV+PI-/+ (total apoptosis rate), P=0.004]. Compared with group a, the expression of CD41a in group c was much higher (P=0.000). The expression of CD41a in group b was higher than that in group a (P=0.015), but still much less than that in group c (P=0.000). Compared with group a, the early and total apoptosis rate in group b, c and the late apoptosis rate in group c were decreased obviously (all P=0.000), whereas there was no obvious change of the late apoptosis rate in group b. However, compared with group c, the late and total apoptosis rate in group b were significantly increased (both P=0.000). The expression levels of IL6, SCF mRNA and IL6 protein were significantly decreased in ITP BMCs (all P=0.000), but there was no obvious difference in the expression levels of IL11 and TPO between ITP BMCs and NC BMCs. Conclusion • BMCs from ITP patients show some defects in supporting megakaryocytic differentiation and survival under co-culture conditions, which mechanisms are related to the reduction of IL6 and SCF expression.