Stem cells and fluid flow drive cyst formation in an invertebrate excretory organ.
Ontology highlight
ABSTRACT:
SUBMITTER: Thi-Kim Vu H
PROVIDER: S-EPMC4500094 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Researchers have long awaited the technology to develop an in vitro kidney model. Here, we establish a rapid fabricating technique for kidney-like tissues (cysts) using a combination of an organ-derived extracellular matrix (ECM) gel format culture system and a renal stem cell line (CHK-Q cells). CHK-Q cells, which are spontaneously immortalized from the renal stem cells of the Chinese hamster, formed renal cyst-like structures in a type-I collagen gel sandwich culture on day 1 of culture. The cysts fused together and expanded while maintaining three-dimensional structures. The expression of genes related to kidney development and maturation was increased compared with that in a traditional monolayer. Under the kidney-derived ECM (K-ECM) gel format culture system, cyst formation and maturation were induced rapidly. Gene expressions involved in cell polarities, especially for important material transporters (typical markers Slc5a1 and Kcnj1), were restored. K-ECM composition was an important trigger for CHK-Q cells to promote kidney-like tissue formation and maturation. We have established a renal cyst model which rapidly expressed mature kidney features via the combination of K-ECM gel format culture system and CHK-Q cells.
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Project description:Liquid in a Petri dish spontaneously circulates in a radial pattern, even when the dish is at rest. These fluid flows have been observed and utilized for biological research, but their origins have not been well-studied. Here we used particle-tracking to measure velocities of radial fluid flows, which are shown to be linked to evaporation. Infrared thermal imaging was used to identify thermal gradients at the air-liquid interface and at the bottom of the dish. Two-color ratiometric fluorescence confocal imaging was used to measure thermal gradients in the vertical direction within the fluid. A finite-element model of the fluid, incorporating the measured temperature profiles, shows that buoyancy forces are sufficient to produce flows consistent with the measured particle velocity results. Such flows may arise in other dish or plate formats, and may impact biological research in positive or negative ways.
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Project description:In common with most mammals, humans form only two dentitions during their lifetime. Occasionally, supernumerary teeth develop in addition to the normal complement. Odontoma represent a small group of malformations containing calcified dental tissues of both epithelial and mesenchymal origin, with varying levels of organization, including tooth-like structures. The specific cell type responsible for the induction of odontoma, which retains the capacity to re-initiate de novo tooth development in postnatal tissues, is not known. Here we demonstrate that aberrant activation of WNT signaling by expression of a non-degradable form of β-catenin specifically in SOX2-positive postnatal dental epithelial stem cells is sufficient to generate odontoma containing multiple tooth-like structures complete with all dental tissue layers. Genetic lineage-tracing confirms that odontoma form in a similar manner to normal teeth, derived from both the mutation-sustaining epithelial stem cells and adjacent mesenchymal tissues. Activation of the WNT pathway in embryonic SOX2-positive progenitors results in ectopic expression of secreted signals that promote odontogenesis throughout the oral cavity. Significantly, the inductive potential of epithelial dental stem cells is retained in postnatal tissues, and up-regulation of WNT signaling specifically in these cells is sufficient to promote generation and growth of ectopic malformations faithfully resembling human odontoma.
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Project description:Genomic and genetic analyses have demonstrated that many species contain multiple chemotaxis-like signal transduction cascades that likely control processes other than chemotaxis. The Che? signal transduction cascade from Rhodospirillum centenum is one such example that regulates development of dormant cysts. This Che-like cascade contains two hybrid response regulator-histidine kinases, CheA? and CheS?, and a single-domain response regulator CheY?. We demonstrate that cheS? is epistatic to cheA? and that only CheS??P can phosphorylate CheY?. We further show that CheA? derepresses cyst formation by phosphorylating a CheS? receiver domain. These results demonstrate that the flow of phosphate as defined by the paradigm E. coli chemotaxis cascade does not necessarily hold true for non-chemotactic Che-like signal transduction cascades.
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Project description:BACKGROUND: There is little knowledge concerning the content and the mechanisms of filling of arachnoid cysts. The aim of this study was to compare the protein content of arachnoid cysts and cerebrospinal fluid by quantitative proteomics to increase the understanding of arachnoid cysts. METHODS: Arachnoid cyst fluid and cerebrospinal fluid from five patients were analyzed by quantitative proteomics in two separate experiments.In a label-free experiment arachnoid cyst fluid and cerebrospinal fluid samples from individual patients were trypsin digested and analyzed by Orbitrap mass spectrometry in a label-free manner followed by data analysis using the Progenesis software.In the second proteomics experiment, a patient sample pooling strategy was followed by MARS-14 immunodepletion of high abundant proteins, trypsin digestion, iTRAQ labelling, and peptide separation by mix-phase chromatography followed by Orbitrap mass spectrometry analysis. The results from these analyzes were compared to previously published mRNA microarray data obtained from arachnoid membranes. RESULTS: We quantified 348 proteins by the label-free individual patient approach and 1425 proteins in the iTRAQ experiment using a pool from five patients of arachnoid cyst fluid and cerebrospinal fluid. This is by far the largest number of arachnoid cyst fluid proteins ever identified, and the first large-scale quantitative comparison between the protein content of arachnoid cyst fluid and cerebrospinal fluid from the same patients at the same time. Consistently in both experiment, we found 22 proteins with significantly increased abundance in arachnoid cysts compared to cerebrospinal fluid and 24 proteins with significantly decreased abundance. We did not observe any molecular weight gradient over the arachnoid cyst membrane. Of the 46 proteins we identified as differentially abundant in our study, 45 were also detected from the mRNA expression level study. None of them were previously reported as differentially expressed. We did not quantify any of the proteins corresponding to gene products from the ten genes previously reported as differentially abundant between arachnoid cysts and control arachnoid membranes. CONCLUSIONS: From our experiments, the protein content of arachnoid cyst fluid and cerebrospinal fluid appears to be similar. There were, however, proteins that were significantly differentially abundant between arachnoid cyst fluid and cerebrospinal fluid. This could reflect the possibility that these proteins are affected by the filling mechanism of arachnoid cysts or are shed from the membranes into arachnoid cyst fluid. Our results do not support the proposed filling mechanisms of oncotic pressure or valves.
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Project description:Background:
* Researchers are trying to learn what causes certain types of cancer to spread to other organs in the body (metastasis). Cancer tumors may produce a very small number of specific cells (cancer stem cells) that cause the tumors to grow in other organs throughout the body.
* By examining cancer tumor tissue, normal tissue, blood, bone marrow, and other body fluids, researchers may determine whether these samples contain cancer stem cells. Cancer stem cells may provide information on whether the cancer will come back or spread before other routine x-ray studies or lab tests indicate its presence.
Objectives:
* To acquire a collection of solid organ cancer stem cells for future study.
* To analyze solid organ cancer stem cells from various types of cancer on a genetic level.
* To determine if solid organ cancer stem cells are present in the blood or bone marrow.
Eligibility:
* Patients 16 years of age and older who have solid organ cancer (cancer in the liver, colon, rectum, anus, pancreas, stomach, breast, skin, muscles, fat, connective tissue, uterus, ovary, cervix, vagina, vulva, or inner lining of the abdomen) or a precancerous growth, and who are scheduled to have a biopsy or surgery to remove the cancer as part of their treatment.
Design:
* This is a prospective trial designed to procure solid organ cancer stem cells before either surgery or biopsy.
* All patients registered to this trial will undergo surgery to extirpate their cancer in the NCI
* Prior to surgery or biopsy, 8 tablespoons of blood will be drawn.
* During the surgery or biopsy, a sample of normal tissue will be removed along with the cancerous or precancerous tissue. If separate consent is given, samples of bone marrow will also be taken.
* After discharge, patients will return to the clinic for routine visits every month for the first 3 months following surgery, and then about every 3 months for 2 years, and then every 6 months for 3 years. During the visits, patients will have routine blood and imaging studies done, and researchers will take additional blood samples (about 8 tablespoons at each visit) and optional bone marrow samples (4 teaspoons every 6 months) to be used for research.
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Project description:Doublecortin-like kinase 1 (DCLK1)-positive pancreatic cancer stem cells develop at a precancerous stage and may contribute to the lack of efficacy of pancreatic cancer therapy. Although PanIN cells express oncogenic KRas and have an increased activity of epidermal growth factor receptor (EGFR), we demonstrate that, in DCLK1+ PanIN cells, EGFR signaling is not propagated to the nucleus. Mimicking blockage of EGFR with erlotinib in PanIN organoid culture or in p48cre;KrasG12D mice led to a significant increase in DCLK1+ PanIN cells. As a mechanism of how EGFR inhibition leads to formation of DCLK1+ cells, we identify an increase in hydrogen peroxide contributing to activation of Protein Kinase D1 (PKD1). Active PKD1 then drives stemness and abundance of DCLK1+ cells in lesions. Our data suggest a signaling mechanism that leads to the development of DCLK1+ pancreatic cancer stem cells, which can be exploited to target this population in potential therapeutic approaches.
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