STAT5-regulated microRNA-193b controls haematopoietic stem and progenitor cell expansion by modulating cytokine receptor signalling.

Haetscher N, Feuermann Y, Wingert S, Rehage M, Thalheimer FB, Weiser C, Bohnenberger H, Jung K, Schroeder T, Serve H, Oellerich T, Hennighausen L, Rieger MA
Nature communications 2015; 62015: 8928


Haematopoietic stem cells (HSCs) require the right composition of microRNAs (miR) for proper life-long balanced blood regeneration. Here we show a regulatory circuit that prevents excessive HSC self-renewal by upregulation of miR-193b upon self-renewal promoting thrombopoietin (TPO)-MPL-STAT5 signalling. In turn, miR-193b restricts cytokine signalling, by targeting the receptor tyrosine kinase c-KIT. We generated a miR-193b knockout mouse model to unravel the physiological function of miR-193b in haematopoiesis. MiR-193b(-/-) mice show a selective gradual enrichment of functional HSCs, which are fully competent in multilineage blood reconstitution upon transplantation. The absence of miR-193b causes an accelerated expansion of HSCs, without altering cell cycle or survival, but by decelerating differentiation. Conversely, ectopic miR-193b expression restricts long-term repopulating HSC expansion and blood reconstitution. MiR-193b-deficient haematopoietic stem and progenitor cells exhibit increased basal and cytokine-induced STAT5 and AKT signalling. This STAT5-induced microRNA provides a negative feedback for excessive signalling to restrict uncontrolled HSC expansion.

Affiliation: LOEWE Center for Cell and Gene Therapy and Department of Medicine, Hematology/Oncology, Goethe University Frankfurt, Theodor-Stern-Kai 7, Frankfurt 60590, Germany.

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