Stem Cell Reports Ar ticle Multipotent Hematopoietic Progenitors Divide Asymmetrically to Create Progenitors of the Lymphomyeloid and Erythromyeloid Lineages Andre ´ Go ¨rgens, 1,2, * Anna-Kristin Ludwig, 1 Michael Mo ¨llmann, 3 Adalbert Krawczyk, 4 Jan Du ¨rig, 3 Helmut Hanenberg, 5 Peter A. Horn, 1,2 and Bernd Giebel 1,2, * 1 Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Virchowstraße 179, 45147 Essen, Germany 2 German Cancer Consortium (DKTK) 3 Department of Hematology, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45122 Essen, Germany 4 Institute of Virology, University Hospital Essen, University of Duisburg-Essen, Virchowstraße 179, 45147 Essen, Germany 5 Riley Hospital for Children, Indiana University School of Medicine, 705 Riley Hospital Drive, Indianapolis, IN 46202, USA *Correspondence: andre.goergens@uk-essen.de (A.G.), bernd.giebel@uk-essen.de (B.G.) http://dx.doi.org/10.1016/j.stemcr.2014.09.016 This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). SUMMARY Hematopoietic stem and progenitor cells (HSPCs) can self-renew and create committed progenitors, a process supposed to involve asym- metric cell divisions (ACDs). Previously, we had linked the kinetics of CD133 expression with ACDs but failed to detect asymmetric segre- gation of classical CD133 epitopes on fixed, mitotic HSPCs. Now, by using a novel anti-CD133 antibody (HC7), we confirmed the occur- rence of asymmetric CD133 segregation on paraformaldehyde-fixed and living HSPCs. After showing that HC7 binding does not recognizably affect biological features of human HSPCs, we studied ACDs in different HSPC subtypes and determined the developmental potential of arising daughter cells at the single-cell level. Approximately 70% of the HSPCs of the multipotent progenitor (MPP) fraction studied performed ACDs, and about 25% generated lymphoid-primed multipotent progenitor (LMPP) as wells as erythromyeloid progen- itor (EMP) daughter cells. Since MPPs hardly created daughter cells maintaining MPP characteristics, our data suggest that under conven- tional culture conditions, ACDs are lineage instructive rather than self-renewing. INTRODUCTION Hematopoietic stem cells (HSCs) are defined as clono- genic cells that are able to self-renew and generate he- matopoietic progenitor cells (HPCs) of all hematopoietic lineages. Triggered by the discovery of HSC niches (Calvi et al., 2003; Schofield, 1978; Zhang et al., 2003), the un- derstanding of the mechanisms and molecules involved in cell-fate decisions of HSCs has increased considerably (Le ´vesque et al., 2010; Lymperi et al., 2010). Recently, experimental evidence has been provided that HSCs and distinct HPCs occupy different cellular niches: while lymphoid progenitors inhabit endosteal niches, murine HSCs reside in perivascular niches that specifically depend on mesenchymal stromal cells (MSCs) and endo- thelial cells (Ding and Morrison, 2013; Greenbaum et al., 2013). In addition to extrinsic factors provided by the environments of the different hematopoietic niches, he- matopoietic stem and progenitor cells (HSPCs) contain the capability to divide asymmetrically, demonstrating that intrinsically controlled programs also participate in cell-fate specification processes (Giebel, 2008; Go ¨rgens and Giebel, 2010). Evidence for the occurrence of asymmetric cell divisions (ACDs) during human early hematopoiesis was initially provided by the observation that 30% of dividing CD34 + or CD34 + CD38 low/ cells created daughter cells that followed different proliferation kinetics and adopted different cell fates (Brummendorf et al., 1998; Huang et al., 1999; Punzel et al., 2002). At a similar proportion, dividing CD133 + CD34 + HSPCs were found to create CD133 low CD34 + cells (Beckmann et al., 2007). By studying the subcellular distribution of cell-surface antigens that are differentially expressed on CD133 + CD34 + and CD133 low CD34 + cells, we previously identified four cell- surface antigens that segregate asymmetrically in 20%– 30% of dividing HSPCs and confirmed the hypothesis that human HSPCs can divide asymmetrically (Beckmann et al., 2007). Recently, we comprehensively compared the developmental potential of human umbilical cord blood (UCB)-derived CD34 + cells that expressed either high CD133 (CD133 + ) or low/no CD133 (CD133  ) levels on their cell surface. We demonstrated that CD133 + CD34 + HSPCs can be subdivided by means of their CD45RA, CD38, and CD10 expression into different cell fractions, being enriched for multipotent progenitors (MPPs; CD133 + CD34 + CD38  CD45RA  CD10  ), lymphoid-primed multi- potent progenitors (LMPPs; CD133 + CD34 + CD38  CD45RA + CD10  ), multilymphoid progenitors (MLPs; CD133 + CD34 + CD38  CD45RA + CD10 + ), or granulocyte-macro- phage progenitors (GMPs; CD133 + CD34 + CD38 + CD45RA + CD10  ). The vast majority of CD133  CD34 + progenitors were found to belong to the erythromyeloid lineage whose common progenitors were determined to be er- ythromyeloid progenitors (EMPs; CD133  CD34 + CD38 + CD45RA  CD10  )(Go ¨rgens et al., 2013b). Stem Cell Reports j Vol. 3 j 1–15 j December 9, 2014 j ª2014 The Authors 1 Please cite this article in press as: Go ¨rgens et al., Multipotent Hematopoietic Progenitors Divide Asymmetrically to Create Progenitors of the Lymphomyeloid and Erythromyeloid Lineages, Stem Cell Reports (2014), http://dx.doi.org/10.1016/j.stemcr.2014.09.016