Leucine-rich Repeat-containing G-protein-coupled Receptor 5 Marks Short-term Hematopoietic Stem and Progenitor Cells during Mouse Embryonic Development

Abstract

Background: Lgr5 was shown to mark proliferating stem cells in several adult organs. Results: Lgr5 expression was detected in proliferating hematopoietic stem and progenitor cells (HSPCs) at the early stage of hematopoiesis. Conclusion: Lgr5 marks short-term (ST) hematopoietic stem and progenitor cells during the embryonic and fetal hematopoiesis. Significance: Extending Lgr5 as a HSPC marker into the hematopoietic system during development.

Leucine-rich repeat–containing G-protein–coupled receptor 5–positive cells in the endometrial stem cell niche

“…The characterization of endometrial LGR5 þ cells reveals the absence of an endothelial, mesenchymal, or pure hematopoietic profile, but the presence of high CD45 expression. Clever's group also identified CD45 þ cells in an LGR5 þ hematopoietic stem cell fraction during mouse embryonic development and, consistently with our study, found that these cells reconstituted hematopoietic lineages in adult mice after transplantation although with very low efficiency (32). Moreover, the comparison of the gene expression profile of the positive and negative populations for CD45 (LGR5 þ CD45 þ versus LGR5 þ CD45 À ) revealed no significant differences between the subpopulations despite the small number of samples assessed (n ¼ 3).…”

“…The macroscopic appearance (morphology and thickening) of the reconstructed endometrial tissue was not like previous results in the in vivo nonhuman animal model (7)(8)(9)(10)(11), suggesting that we likely did not isolate a pure SSC population. Indeed, the reconstitution ability was very low, and a clear limitation is not only the low number of cells injected (2,000 and 20,000), but also the low efficiency of LGR5 þ cells to reconstitute original cell lineages after transplantation (corroborated by Clever' s group in 2014 [32]).…”

Lgr6 is a stem cell marker in mouse skin squamous cell carcinoma

“…Lrig1 3 , 4 defines a cell population in the HF junctional zone that serves to maintain the HF infundibulum 5 – 7 , while quiescent Krt15 -positive stem cells in the bulge region act as a reserve stem cell pool that becomes activated in response to stress 8 . Lgr4-6 are expressed in stem cells in many tissues, including the small intestine 9 , breast 10 , ovary 11 , 12 and haematopoietic system 13 . In the skin, Lgr5 has been genetically linked to a network of genes that are expressed specifically in the HF 14 , 15 , while Lgr6 is expressed in the isthmus region, sebaceous gland and interfollicular epidermis 16 17 .…”

Caught in a Wnt storm: Complexities of Wnt signaling in hematopoiesis

“…Lgr5 is not, or at very low levels, expressed in adult hematopoietic stem and progenitor cells (HSPCs). In aorta-gonad-mesonephros (AGM) derived and fetal liver derived HSCs Lgr5 is lowly expressed as well (72). A portion of these Lgr5+ cells express Runx1 and other HSPC surface markers like c-Kit and CD34 in the AGM, or CD41 in fetal liver.…”