Abstract:This paper reviews the importance of mesenchymal-epithelial interactions in development and gives detailed technical protocols for investigating these interactions. Successful analysis of mesenchymal-epithelial interactions requires knowing the ages in which embryonic, neonatal and adult organs can be separated into mesenchymal and epithelial tissues. Methods for separation of mesenchymal and epithelial and preparation of tissue recombinants are described.
“…2a ). These data provided a valuable chance to identify the interactions between epithelium and mesenchyme, one of the fundamental developmental mechanisms responsible for the development of the majority of organs [ 1 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The onset of mouse organogenesis begins at approximately E8.0, and the buds of all major organs are essentially formed at E9.5. Along with development, interactions between epithelium and mesenchyme are crucial for the proper development of all organs with epithelial parenchyma [ 1 ]. Through interactions with the mesenchyme, epithelial identity is induced and specified [ 2 , 3 ].…”
BackgroundOrganogenesis is crucial for proper organ formation during mammalian embryonic development. However, the similarities and shared features between different organs and the cellular heterogeneity during this process at single-cell resolution remain elusive.ResultsWe perform single-cell RNA sequencing analysis of 1916 individual cells from eight organs and tissues of E9.5 to E11.5 mouse embryos, namely, the forebrain, hindbrain, skin, heart, somite, lung, liver, and intestine. Based on the regulatory activities rather than the expression patterns, all cells analyzed can be well classified into four major groups with epithelial, mesodermal, hematopoietic, and neuronal identities. For different organs within the same group, the similarities and differences of their features and developmental paths are revealed and reconstructed.ConclusionsWe identify mutual interactions between epithelial and mesenchymal cells and detect epithelial cells with prevalent mesenchymal features during organogenesis, which are similar to the features of intermediate epithelial/mesenchymal cells during tumorigenesis. The comprehensive transcriptome at single-cell resolution profiled in our study paves the way for future mechanistic studies of the gene-regulatory networks governing mammalian organogenesis.Electronic supplementary materialThe online version of this article (10.1186/s13059-018-1416-2) contains supplementary material, which is available to authorized users.
“…2a ). These data provided a valuable chance to identify the interactions between epithelium and mesenchyme, one of the fundamental developmental mechanisms responsible for the development of the majority of organs [ 1 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The onset of mouse organogenesis begins at approximately E8.0, and the buds of all major organs are essentially formed at E9.5. Along with development, interactions between epithelium and mesenchyme are crucial for the proper development of all organs with epithelial parenchyma [ 1 ]. Through interactions with the mesenchyme, epithelial identity is induced and specified [ 2 , 3 ].…”
BackgroundOrganogenesis is crucial for proper organ formation during mammalian embryonic development. However, the similarities and shared features between different organs and the cellular heterogeneity during this process at single-cell resolution remain elusive.ResultsWe perform single-cell RNA sequencing analysis of 1916 individual cells from eight organs and tissues of E9.5 to E11.5 mouse embryos, namely, the forebrain, hindbrain, skin, heart, somite, lung, liver, and intestine. Based on the regulatory activities rather than the expression patterns, all cells analyzed can be well classified into four major groups with epithelial, mesodermal, hematopoietic, and neuronal identities. For different organs within the same group, the similarities and differences of their features and developmental paths are revealed and reconstructed.ConclusionsWe identify mutual interactions between epithelial and mesenchymal cells and detect epithelial cells with prevalent mesenchymal features during organogenesis, which are similar to the features of intermediate epithelial/mesenchymal cells during tumorigenesis. The comprehensive transcriptome at single-cell resolution profiled in our study paves the way for future mechanistic studies of the gene-regulatory networks governing mammalian organogenesis.Electronic supplementary materialThe online version of this article (10.1186/s13059-018-1416-2) contains supplementary material, which is available to authorized users.
“…Timed-pregnant mice at gestational days 14–16 were used to obtain fetal urogenital sinus (UGS), as previously described (Cunha and Donjacour, 1987; Cunha and Baskin, 2016a). The UGS tissue was incubated in 1% trypsin (#215240, BD Diagnostic Systems, Sparks, MD) in Hanks CMF for 90 min at 4°C to digest the basement membrane between the UGM and urogenital sinus epithelium (UGE), then washed in Hanks CMF and placed into 20% fetal calf serum/Hanks CMF to halt trypsinization.…”
Section: Methodsmentioning
confidence: 99%
“…Resultant tissue recombinants were incubated overnight at 37°C and 5% CO 2 . The following day, tissue recombinants were grafted under the kidney capsule of nude male hosts (Cunha and Baskin, 2016a). As controls, GFP − -UGM alone or GFP − -UGM + GFP + -UtE were also grafted under the kidney capsule of nude mouse hosts.…”
Section: Methodsmentioning
confidence: 99%
“…Back skin (1 mm 2 ) was obtained from gestational day 14–16 fetuses and grafts prepared as described previously (Simon et al , 2009; Simon et al , 2013; Cunha and Baskin, 2016a). The FD and epidermis was separated after trypsinization.…”
Stem Leydig cells (SLCs), precursors of testicular Leydig cells that secrete testosterone required for male sexual differentiation, spermatogenesis and fertility, were recently identified in rat testes. Various types of stem cells have shown the ability to differentiate into other tissues, but there is no information on the plasticity of adult rat SLCs (rSLCs). This study investigated the ability of rSLCs to transdifferentiate into cell types from all three germ layers—prostatic epithelium (endoderm), uterine epithelium (mesoderm) and epidermis (ectoderm)—under the influence of inductive mesenchyme from fetal and neonatal tissues. To differentiate rSLCs into cells of other lineages, mesenchyme from green fluorescent protein (GFP)-expressing mice was used. Tissue recombinants of urogenital sinus mesenchyme (a potent prostate inducer) and rSLCs grafted into adult male hosts formed ductal structures resembling prostate after 5 weeks. Prostate epithelium was of rSLC origin as determined by absence of GFP expression, and expressed characteristic markers of prostatic epithelium. Similarly, uterine mesenchyme + rSLCs tissue recombinants contained a simple columnar epithelium that was histologically similar to normal uterine epithelium and expressed typical uterine epithelial markers, but was of rSLC origin. In contrast, epidermal tissue was absent in fetal dermis + rSLCs recombinants, suggesting rSLCs did not form skin epithelium. Thus, rSLCs can transdifferentiate into uterine and prostatic epithelium, mesodermal and endodermal derivatives, respectively, but they may have a limited transdifferentiation potential, as shown by their inability to form epidermis, an ectodermal derivative.
Exosomes are nanosized membrane-bound extracellular vesicles with the capacity to modify functions and behaviors of recipient cells via transferring unique biological information. Mounting evidence suggests that under developmental conditions, mesenchymal cell-derived exosomes are capable of mediating intercellular communication between epithelium and mesenchyme during organogenesis of salivary gland, tooth, hair follicle, and kidney, shedding light on potential therapeutic benefits elicited by mesenchymal exosomes in nanomedicine. Representing the most extensively investigated multipotent stem cells, mesenchymal stem cells (MSCs) have been identified and extracted from a wide variety of tissues. Accordingly, exosomes derived from MSCs (MSC-Exos) can be easily accessed and manipulated as nanoparticles, giving rise to an entirely new therapeutic agents for nanomedicine. MSC-Exos have presently emerged as efficacious alternatives to MSCs for cell-free therapeutic strategies in disease contexts of ischemic heart disease, cutaneous wound healing and coronavirus disease 2019. In this review, we first present a critical analysis of research state of exosomes in terms of their biogenesis, molecular composition, isolation and characterization, then summarize current understanding of developmental regulation mediated by mesenchymal cell-derived exosomes and reparative potential conferred by MSC-Exos, along with particular emphasis onThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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