scholarly journals Activation of adult mammalian retinal stem cells in vivo via antagonism of BMP and sFRP2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kenneth N. Grisé ◽  
Brenda L. K. Coles ◽  
Nelson X. Bautista ◽  
Derek van der Kooy

Abstract Background The adult mammalian retina does not have the capacity to regenerate cells lost due to damage or disease. Therefore, retinal injuries and blinding diseases result in irreversible vision loss. However, retinal stem cells (RSCs), which participate in retinogenesis during development, persist in a quiescent state in the ciliary epithelium (CE) of the adult mammalian eye. Moreover, RSCs retain the ability to generate all retinal cell types when cultured in vitro, including photoreceptors. Therefore, it may be possible to activate endogenous RSCs to induce retinal neurogenesis in vivo and restore vision in the adult mammalian eye. Methods To investigate if endogenous RSCs can be activated, we performed combinatorial intravitreal injections of antagonists to BMP and sFRP2 proteins (two proposed mediators of RSC quiescence in vivo), with or without growth factors FGF and Insulin. We also investigated the effects of chemically-induced N-methyl-N-Nitrosourea (MNU) retinal degeneration on RSC activation, both alone and in combination withthe injected factors. Further, we employed inducible Msx1-CreERT2 genetic lineage labeling of the CE followed by stimulation paradigms to determine if activated endogenous RSCs could migrate into the retina and differentiate into retinal neurons. Results We found that in vivo antagonism of BMP and sFRP2 proteins induced CE cells in the RSC niche to proliferate and expanded the RSC population. BMP and sFRP2 antagonism also enhanced CE cell proliferation in response to exogenous growth factor stimulation and MNU-induced retinal degeneration. Furthermore, Msx1-CreERT2 genetic lineage tracing revealed that CE cells migrated into the retina following stimulation and/or injury, where they expressed markers of mature photoreceptors and retinal ganglion cells. Conclusions Together, these results indicate that endogenous adult mammalian RSCs may have latent regenerative potential that can be activated by modulating the RSC niche and hold promise as a means for endogenous retinal cell therapy to repair the retina and improve vision.

2021 ◽  
Author(s):  
Xu Fan ◽  
Pei Lu ◽  
Xianghua Cui ◽  
Peng Wu ◽  
Weiran Lin ◽  
...  

Abstract Kupffer cells (KCs) originate from yolk sac progenitors before birth, but the origin of repopulating KCs in adult remains unclear. In current study, we firstly traced the fate of preexisting KCs and that of monocytic cells with tissue-resident macrophage-specific and monocytic cell-specific fate mapping mouse models, respectively, and found no evidences that repopulating KCs originate from preexisting KCs or MOs. Secondly, we performed genetic lineage tracing to determine the type of progenitor cells involved in response to KC depletion in mice, and found that in response to KC depletion, hematopoietic stem cells (HSCs) proliferated in the bone marrow, mobilized into the blood, adoptively transferred into the liver and differentiated into KCs. Finally, we traced the fate of HSCs in a HSC-specific fate-mapping mouse model, in context of chronic liver inflammation induced by repeated carbon tetrachloride treatment, and confirmed that repopulating KCs originated directly from HSCs. Taken together, these findings provided in vivo fate-mapping evidences that repopulating KCs originate directly from hematopoietic stem cells, which present a completely novel understanding of the cellular origin of repopulating Kupffer Cells and shedding light on the divergent roles of KCs in liver homeostasis and diseases.


2019 ◽  
Vol 98 (10) ◽  
pp. 1066-1072 ◽  
Author(s):  
V. Yianni ◽  
P.T. Sharpe

Cells have been identified in postnatal tissues that, when isolated from multiple mesenchymal compartments, can be stimulated in vitro to give rise to cells that resemble mature mesenchymal phenotypes, such as odontoblasts, osteoblasts, adipocytes, and myoblasts. This has made these adult cells, collectively called mesenchymal stem cells (MSCs), strong candidates for fields such as tissue engineering and regenerative medicine. Based on evidence from in vivo genetic lineage–tracing studies, pericytes have been identified as a source of MSC precursors in vivo in multiple organs, in response to injury or during homeostasis. Questions of intense debate and interest in the field of tissue engineering and regenerative studies include the following: 1) Are all pericytes, irrespective of tissue of isolation, equal in their differentiation potential? 2) What are the mechanisms that regulate the differentiation of MSCs? To gain a better understanding of the latter, recent work has utilized ChIP-seq (chromatin immunoprecipitation followed by sequencing) to reconstruct histone landscapes. This indicated that for dental pulp pericytes, the odontoblast-specific gene Dspp was found in a transcriptionally permissive state, while in bone marrow pericytes, the osteoblast-specific gene Runx2 was primed for expression. RNA sequencing has also been utilized to further characterize the 2 pericyte populations, and results highlighted that dental pulp pericytes are already precommitted to an odontoblast fate based on enrichment analysis indicating overrepresentation of key odontogenic genes. Furthermore, ChIP-seq analysis of the polycomb repressive complex 1 component RING1B indicated that this complex is likely to be involved in inhibiting inappropriate differentiation, as it localized to a number of loci of key transcription factors that are needed for the induction of adipogenesis, chondrogenesis, or myogenesis. In this review, we highlight recent data elucidating molecular mechanisms that indicate that pericytes can be tissue-specific precommitted MSC precursors in vivo and that this precommitment is a major driving force behind MSC differentiation.


2020 ◽  
Author(s):  
Xu Fan ◽  
Pei Lu ◽  
Xianghua Cui ◽  
Peng Wu ◽  
Weiran Lin ◽  
...  

AbstractKupffer cells (KCs) originate from yolk sac progenitors before birth. Throughout adulthood, they self-maintain independently from the input of circulating monocytes (MOs) at stead state, and are replenished within 2 weeks after having been depleted, but the origin of repopulating KCs in adult remains unclear. The current paradigm dictates that repopulating KCs originate from preexisting KCs or monocytes, but there remains a lack of fate-mapping evidence. In current study, we firstly traced the fate of preexisting KCs and that of monocytic cells with tissue-resident macrophage-specific and monocytic cell-specific fate mapping mouse models, respectively, and found no evidences that repopulating KCs originate from preexisting KCs or MOs. Secondly, we performed genetic lineage tracing to determine the type of progenitor cells involved in response to KC depletion in mice, and found that in response to KC depletion, hematopoietic stem cells (HSCs) proliferated in the bone marrow, mobilized into the blood, adoptively transferred into the liver and differentiated into KCs. Finally, we traced the fate of HSCs in a HSC-specific fate-mapping mouse model, in context of chronic liver inflammation induced by repeated carbon tetrachloride treatment, and confirmed that repopulating KCs originated directly from HSCs. Taken together, these findings provided strong in vivo fate-mapping evidences that repopulating KCs originate directly from Hematopoietic stem cells not from preexisting KCs or from MOs.SignificanceThere is a standing controversy in the field regarding the cellular origin of repopulating macrophages. This paper provides strong in vivo fate-mapping evidences that repopulating KCs originate directly from hematopoietic stem cells not from preexisting KCs or from MOs, which presenting a completely novel understanding of the cellular origin of repopulating Kupffer Cells and shedding light on the divergent roles of KCs in liver homeostasis and diseases.


2017 ◽  
Vol 216 (6) ◽  
pp. 1833-1847 ◽  
Author(s):  
Xia Tang ◽  
Jianan Gao ◽  
Xinling Jia ◽  
Wencao Zhao ◽  
Yijie Zhang ◽  
...  

In lower vertebrates, retinal stem cells (RSCs) capable of producing all retinal cell types are a resource for retinal tissue growth throughout life. However, the embryonic origin of RSCs remains largely elusive. Using a Zebrabow-based clonal analysis, we characterized the RSC niche in the ciliary marginal zone of zebrafish retina and illustrate that blood vessels associated with RSCs are required for the maintenance of actively proliferating RSCs. Full lineage analysis of RSC progenitors reveals lineage patterns of RSC production. Moreover, in vivo lineage analysis demonstrates that these RSC progenitors are the direct descendants of a set of bipotent progenitors in the medial epithelial layer of developing optic vesicles, suggesting the involvement of the mixed-lineage states in the RSC lineage specification.


2015 ◽  
Vol 34 (11) ◽  
pp. 1572-1588 ◽  
Author(s):  
Robert Reinhardt ◽  
Lázaro Centanin ◽  
Tinatini Tavhelidse ◽  
Daigo Inoue ◽  
Beate Wittbrodt ◽  
...  

Author(s):  
Wanbo Tang ◽  
Jian He ◽  
Tao Huang ◽  
Zhijie Bai ◽  
Chaojie Wang ◽  
...  

In the aorta-gonad-mesonephros (AGM) region of mouse embryos, pre-hematopoietic stem cells (pre-HSCs) are generated from rare and specialized hemogenic endothelial cells (HECs) via endothelial-to-hematopoietic transition, followed by maturation into bona fide hematopoietic stem cells (HSCs). As HECs also generate a lot of hematopoietic progenitors not fated to HSCs, powerful tools that are pre-HSC/HSC-specific become urgently critical. Here, using the gene knockin strategy, we firstly developed an Hlf-tdTomato reporter mouse model and detected Hlf-tdTomato expression exclusively in the hematopoietic cells including part of the immunophenotypic CD45– and CD45+ pre-HSCs in the embryonic day (E) 10.5 AGM region. By in vitro co-culture together with long-term transplantation assay stringent for HSC precursor identification, we further revealed that unlike the CD45– counterpart in which both Hlf-tdTomato-positive and negative sub-populations harbored HSC competence, the CD45+ E10.5 pre-HSCs existed exclusively in Hlf-tdTomato-positive cells. The result indicates that the cells should gain the expression of Hlf prior to or together with CD45 to give rise to functional HSCs. Furthermore, we constructed a novel Hlf-CreER mouse model and performed time-restricted genetic lineage tracing by a single dose induction at E9.5. We observed the labeling in E11.5 AGM precursors and their contribution to the immunophenotypic HSCs in fetal liver (FL). Importantly, these Hlf-labeled early cells contributed to and retained the size of the HSC pool in the bone marrow (BM), which continuously differentiated to maintain a balanced and long-term multi-lineage hematopoiesis in the adult. Therefore, we provided another valuable mouse model to specifically trace the fate of emerging HSCs during development.


2021 ◽  
Author(s):  
Camille Boudreau-Pinsonneault ◽  
Awais Javed ◽  
Michel Fries ◽  
Pierre Mattar ◽  
Michel Cayouette

Temporal identity factors are sufficient to reprogram developmental competence of neural progenitors, but whether they could also reprogram the identity of fully differentiated cells is unknown. To address this question, we designed a conditional gene expression system combined with genetic lineage tracing that allows rapid screening of potential reprogramming factors in the mouse retina. Using this assay, we report that co-expression of the early temporal identity transcription factor Ikzf1, together with Ikzf4, another Ikaros family member, is sufficient to directly convert adult Muller glial cells into neuron-like cells in vivo, without inducing a proliferative progenitor state. scRNA-seq analysis shows that the reprogrammed cells share some transcriptional signatures with both cone photoreceptors and bipolar cells. Furthermore, we show that co-expression of Ikzf1 and Ikzf4 can reprogram mouse embryonic fibroblasts to induced neurons by remodeling chromatin and promoting a neuronal gene expression program. This work uncovers general neuronal reprogramming properties for temporal identity factors in differentiated cells, opening new opportunities for cell therapy development.


2018 ◽  
Vol 115 (4) ◽  
pp. E610-E619 ◽  
Author(s):  
Onur Basak ◽  
Teresa G. Krieger ◽  
Mauro J. Muraro ◽  
Kay Wiebrands ◽  
Daniel E. Stange ◽  
...  

The adult mouse subependymal zone provides a niche for mammalian neural stem cells (NSCs). However, the molecular signature, self-renewal potential, and fate behavior of NSCs remain poorly defined. Here we propose a model in which the fate of active NSCs is coupled to the total number of neighboring NSCs in a shared niche. Using knock-in reporter alleles and single-cell RNA sequencing, we show that the Wnt target Tnfrsf19/Troy identifies both active and quiescent NSCs. Quantitative analysis of genetic lineage tracing of individual NSCs under homeostasis or in response to injury reveals rapid expansion of stem-cell number before some return to quiescence. This behavior is best explained by stochastic fate decisions, where stem-cell number within a shared niche fluctuates over time. Fate mapping proliferating cells using a Ki67iresCreER allele confirms that active NSCs reversibly return to quiescence, achieving long-term self-renewal. Our findings suggest a niche-based mechanism for the regulation of NSC fate and number.


Science ◽  
2019 ◽  
Vol 366 (6466) ◽  
pp. 734-738 ◽  
Author(s):  
Antoine de Morree ◽  
Julian D. D. Klein ◽  
Qiang Gan ◽  
Jean Farup ◽  
Andoni Urtasun ◽  
...  

Adult stem cells are essential for tissue homeostasis. In skeletal muscle, muscle stem cells (MuSCs) reside in a quiescent state, but little is known about the mechanisms that control homeostatic turnover. Here we show that, in mice, the variation in MuSC activation rate among different muscles (for example, limb versus diaphragm muscles) is determined by the levels of the transcription factor Pax3. We further show that Pax3 levels are controlled by alternative polyadenylation of its transcript, which is regulated by the small nucleolar RNA U1. Isoforms of the Pax3 messenger RNA that differ in their 3′ untranslated regions are differentially susceptible to regulation by microRNA miR206, which results in varying levels of the Pax3 protein in vivo. These findings highlight a previously unrecognized mechanism of the homeostatic regulation of stem cell fate by multiple RNA species.


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