Lymphoblastoid cell lines (LCLs), originally collected as renewable sources of DNA, are now being used as a model system to study genotype-phenotype relationships in human cells. These cell lines have been used to search for genetic variants that are associated with drug response as well as with more basic cellular traits such as RNA levels. In setting out to extend such studies by searching for genetic variants contributing to drug response, we observed that phenotypes in LCLs were, in our lab and others, significantly affected by experimental confounders (i.e. in vitro growth rate, metabolic state, and relative levels of the Epstein-Barr virus used to transform the cells). As we did not find any SNPs associated with genome-wide significance to drug response, we evaluated whether incorporating RNA expression levels (and eQTLs) in the analysis could increase power to detect such effects. As previously shown, cis-acting eQTLs were detectable for a sizeable fraction of RNAs and baseline levels of many RNAs predicted response to several drugs. However, we found only limited evidence that SNPs influenced drug response through their effect on expression of RNA. Efforts to use LCLs to map genes underlying cellular traits will require great care to control experimental confounders, unbiased methods for integrating and interpreting such multi-dimensional data, and much larger sample sizes than have been applied to date.
Genetic analysis of human traits in vitro: drug response and gene expression in lymphoblastoid cell lines.
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View SamplesMouse keratinocytes were isolated from K15-EGFP transgenic mice for FACS sorting. RNA samples from EGFP-high and alpha-6 integrin positive cells (hair follicle stem cells) and from EGFP negative and alpha-6 integrin positive cells were used for Microarray analysis.
Capturing and profiling adult hair follicle stem cells.
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View SamplesAnalysis of root gene expression of salt-tolerant genotypes FL478, Pokkali and IR63731, and salt-sensitive genotype IR29 under control and salinity-stressed conditions during vegetative growth. Results provide insight into the genetic basis of salt tolerance in indica rice.
Root-specific transcript profiling of contrasting rice genotypes in response to salinity stress.
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View SamplesAndrogenetic alopecia (AGA) or common baldness results from a marked decrease in hair follicle size. This miniaturization may be related to loss of hair follicle stem or progenitor cells. To test this hypothesis, we analyzed bald and non-bald scalp from the same individuals for the presence of hair follicle stem and progenitor cells using flow cytometry to quantitate cells expressing CYTOKERATIN 15 (KRT15), CD200, CD34 and ALPHA-6-INTEGRIN (ITGA6). High levels of KRT15 expression correlated with stem cell properties of small cell size and quiescence. Cells with the highest level of KRT15 expression were maintained in bald scalp; however, distinct populations of CD200high ITGA6high cells and CD34-positive cells were markedly diminished. Consistent with a progenitor cell phenotype, the diminished populations localized closely to the stem-cell rich bulge area but were larger and more proliferative than the bulge stem cells. In functional assays, analogous CD200 high /Itga6 high cells from murine hair follicles were multipotent and generated new hair follicles in skin reconstitution assays. These findings suggest that a defect in stem cell activation plays a role in the pathogenesis of AGA.
Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells.
Sex, Age, Specimen part
View SamplesMouse back skin was disassociated to single cells, sorted by cell surface markers and tested by microarrray
Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells.
Sex, Age, Specimen part
View SamplesHuman hair follicles from normal areas of the scalp were disassociated to single cells, sorted and tested by microarrray
Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells.
Sex, Specimen part
View SamplesCD133 is expressed by a subpopulation of human fetal hair follicle placode cells during early hair development. Its expression, which is gradually lost as the placode matures, correlates with early morphogenesis.
CD133 expression correlates with membrane beta-catenin and E-cadherin loss from human hair follicle placodes during morphogenesis.
Age, Specimen part
View SamplesWe report transcriptomes of pre-sorted skin wound dermal cells. Post-wounding day (PWD) 12, 15 and 21 Zombie-neg;tdTomatoHi cells were FACS sorted from Sm22-Cre;TdTomato mice. Overall design: Examination of single cell heteregeneity in large skin wounds on PWD 12, 15 and 21
Single-cell analysis reveals fibroblast heterogeneity and myeloid-derived adipocyte progenitors in murine skin wounds.
Specimen part, Cell line, Treatment, Subject
View SamplesTestosterone is necessary for the development of male pattern baldness, known as androgenetic alopecia (AGA); yet the mechanisms for decreased hair growth in this disorder are unclear. Here, we show that prostaglandin D2 synthase (PTGDS) is elevated at the mRNA and protein levels in bald scalp compared to haired scalp of men with AGA. The product of PTGDS enzyme activity, prostaglandin D2 (PGD2), is similarly elevated in bald scalp. During normal follicle cycling in mice Ptgds and PGD2 levels increase immediately preceding the regression phase, suggesting an inhibitory effect on hair growth. We show that PGD2 inhibits hair growth in explanted human hair follicles and when applied topically to mice. Hair growth inhibition requires the PGD2 receptor G protein-coupled receptor 44 (GPR44), but not the prostaglandin D2 receptor 1(PTGDR). Furthermore, we find that a transgenic mouse, K14-Ptgs2, which targets prostaglandin-endoperoxide synthase 2 expression to the skin, demonstrates elevated levels of PGD2 in the skin and develops alopecia, follicular miniaturization and sebaceous gland hyperplasia, which are all hallmarks of human AGA. These results define PGD2 as an inhibitor of hair growth in AGA and suggest the PGD2-GPR44 pathway as a potential target for treatment.
Prostaglandin D2 inhibits hair growth and is elevated in bald scalp of men with androgenetic alopecia.
Specimen part, Subject
View SamplesEfficient growth cone regeneration requires protein synthesis in the adult mammalian brain and spinal cord. Recent evidence suggests that the local availability of protein synthesis machinery in adult mammalian axons may be an indicator of their regenerative capacity. Here we investigated the local protein synthesis capacity in matured cortical axons, which have poor regenerative capacity, yet are critical for recovery following injury due to traumatic brain injury and stroke. This work is the first to biochemically isolate and identify mRNA from mammalian cortical axons, making use of a unique microfluidic platform to isolate axons free of other cellular debris. We first sought to identify mRNA in nave axons that makes up the pool of mRNA available for translation initiated following axotomy. Next, we investigated changes in the mRNA population localized to axons 2 days following axotomy and growth cone regeneration.
Axonal mRNA in uninjured and regenerating cortical mammalian axons.
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