Abstract:Leucine-rich repeat-containing G-protein coupled receptor 5-expressing
(Lgr5+) cells have been identified as stem/progenitor cells in
the circumvallate papillae, and single cultured Lgr5+ cells give rise
to taste cells. Here we use circumvallate papilla tissue to establish a
three-dimensional culture system (taste bud organoids) that develops phenotypic
characteristics similar to native tissue, including a multilayered epithelium
containing stem/progenitor in the outer layers and taste cells in the inner layer… Show more
“…To follow the generation of taste cells in real time, we generated organoids from transgenic mice that express green fluorescent protein (GFP) under the control of the promoters of Trpm5 (type II cell marker) 22, 23 or Gad1 (type III cell marker) 24, 25 . We previously succeeded to generate taste organoids directly from isolated circumvallate papilla tissue 12 , and others have reported that dissociated lingual epithelial cells can generate organoids 26 . However, most of these organoids appear to be non-taste organoids, as taste cell markers could not be detected 26 .Figure 1Tracking the generation of taste cells in cultured organoids.…”
Taste cells undergo constant turnover throughout life; however, the molecular mechanisms governing taste cell generation are not well understood. Using RNA-Seq, we systematically surveyed the transcriptome landscape of taste organoids at different stages of growth. Our data show the staged expression of a variety of genes and identify multiple signaling pathways underlying taste cell differentiation and taste stem/progenitor cell proliferation. For example, transcripts of taste receptors appear only or predominantly in late-stage organoids. Prior to that, transcription factors and other signaling elements are upregulated. RNA-Seq identified a number of well-characterized signaling pathways in taste organoid cultures, such as those involving Wnt, bone morphogenetic proteins (BMPs), Notch, and Hedgehog (Hh). By pharmacological manipulation, we demonstrate that Wnt, BMPs, Notch, and Hh signaling pathways are necessary for taste cell proliferation, differentiation and cell fate determination. The temporal expression profiles displayed by taste organoids may also lead to the identification of currently unknown transducer elements underlying sour, salt, and other taste qualities, given the staged expression of taste receptor genes and taste transduction elements in cultured organoids.
“…To follow the generation of taste cells in real time, we generated organoids from transgenic mice that express green fluorescent protein (GFP) under the control of the promoters of Trpm5 (type II cell marker) 22, 23 or Gad1 (type III cell marker) 24, 25 . We previously succeeded to generate taste organoids directly from isolated circumvallate papilla tissue 12 , and others have reported that dissociated lingual epithelial cells can generate organoids 26 . However, most of these organoids appear to be non-taste organoids, as taste cell markers could not be detected 26 .Figure 1Tracking the generation of taste cells in cultured organoids.…”
Taste cells undergo constant turnover throughout life; however, the molecular mechanisms governing taste cell generation are not well understood. Using RNA-Seq, we systematically surveyed the transcriptome landscape of taste organoids at different stages of growth. Our data show the staged expression of a variety of genes and identify multiple signaling pathways underlying taste cell differentiation and taste stem/progenitor cell proliferation. For example, transcripts of taste receptors appear only or predominantly in late-stage organoids. Prior to that, transcription factors and other signaling elements are upregulated. RNA-Seq identified a number of well-characterized signaling pathways in taste organoid cultures, such as those involving Wnt, bone morphogenetic proteins (BMPs), Notch, and Hedgehog (Hh). By pharmacological manipulation, we demonstrate that Wnt, BMPs, Notch, and Hh signaling pathways are necessary for taste cell proliferation, differentiation and cell fate determination. The temporal expression profiles displayed by taste organoids may also lead to the identification of currently unknown transducer elements underlying sour, salt, and other taste qualities, given the staged expression of taste receptor genes and taste transduction elements in cultured organoids.
“…The circadian clock synchronizes the timing of cell division cycles with 1:1 or 1:2 coupling ratios in different subpopulations of cells, depending on their inherent CCTs (Figure 4C). Intriguingly, these synchronized cell division cycles emerge from heterogeneous CCTs with a multimodal distribution as a result of the coupling (Figure 3; Aihara et al, 2015; Nagoshi et al, 2004). Importantly, we also uncover WNT-mediated intercellular coupling between circadian rhythms and the cell cycle in 3D enteroids.…”
SUMMARY
Circadian clock-gated cell division cycles are observed from cyanobacteria to mammals via intracellular molecular connections between these two oscillators. Here we demonstrate WNT-mediated intercellular coupling between the cell cycle and circadian clock in 3D murine intestinal organoids (enteroids). The circadian clock gates a population of cells with heterogeneous cell-cycle times that emerge as 12-hr synchronized cell division cycles. Remarkably, we observe reduced-amplitude oscillations of circadian rhythms in intestinal stem cells and progenitor cells, indicating an intercellular signal arising from differentiated cells governing circadian clock-dependent synchronized cell division cycles. Stochastic simulations and experimental validations reveal Paneth cell-secreted WNT as the key intercellular coupling component linking the circadian clock and cell cycle in enteroids.
“…Sutherland and colleagues termed their Chinese hamster V79 lung cell aggregates "multicellular spheroids" and further described the three typical zones found in most of these 3D spherical cultures: an inner necrotic layer, an intermediate zone of quiescent cells as well as an outer stratum of proliferating cells [18]. However, depending on the application, small spheroids can be generated to avoid a necrotic core [19]. Spheroids are mostly made by the hanging drop method [20,21] or by the use of non-adherent U-bottom shaped plates [22].…”
Abstract. Skin fulfils a plethora of eminent physiological functions ranging from physical barrier over immunity shield to the interface mediating social interaction. Prone to several acquired and inherited diseases, skin is therefore a major target of pharmaceutical and cosmetic research. The lack of similarity between human and animal skin and rising ethical concerns in the use of animal models have driven the search for novel realistic three-dimensional skin models. This review provides a survey of contemporary skin models and compares them in terms of applicability, reliability, cost and complexity.Keywords: Skin, phenotypic screening, 3D models, pharmaceutical research
Skin -composition and functionHuman skin covers an area of almost 2 m 2 in the adult and consists of the three major layers, subcutis, dermis, and epidermis. The subcutis is composed of adipose and epithelial cells. It harbours blood vessels, neurites of peripheral neurons, Vater-Pacini mechanosensors, and, partially, also sweat glands and hair follicles. It connects the skin to periosteum and fascia, absorbs forces, and mediates thermal insulation. The dermis supplies the epidermis with mechanical support and nutrients. It is stratified into an inner, reticular, and an outer, papillary, zone. The dermis houses most sebaceous glands, sweat glands, hair follicles, smooth muscle cells, and capillary beds and, thus, regulates skin moisture, body temperature, and performs the secretory function of skin. The papillary layer is characterized by relatively loose connective tissue, where Meissner corpuscles sense touch. Immune cells, particularly mast cells and dendritic cells, are patrolling in the papillary layer and mediate local inflammatory reactions and immune surveillance. Finally, dermal fibroblasts secrete extracellular matrix (ECM) and basement membrane components. These are primarily collagens I and III, and a proteoglycan-rich ground substance [1]. The resulting ECM mediates tensile strength of the dermis. The dermo-epidermal junction is centered around a special basement membrane. This is composed of a laminin/collagen IV scaffold and further typical basement membrane components such as perlecans and nidogens [1].The epidermis is a squamous epithelium of 50-100 m thickness. It is devoid of blood vessels but contains keratinocytes, Merkel cell mechanosensors, Langerhans immune cells, and melanocytes. The 1 These authors contributed equally.
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