Search results for " LINEAGE"
showing 10 items of 153 documents
A Cre-inducible diphtheria toxin receptor mediates cell lineage ablation after toxin administration.
2004
A new system for lineage ablation is based on transgenic expression of a diphtheria toxin receptor (DTR) in mouse cells and application of diphtheria toxin (DT). To streamline this approach, we generated Cre-inducible DTR transgenic mice (iDTR) in which Cre-mediated excision of a STOP cassette renders cells sensitive to DT. We tested the iDTR strain by crossing to the T cell- and B cell-specific CD4-Cre and CD19-Cre strains, respectively, and observed efficient ablation of T and B cells after exposure to DT. In MOGi-Cre/iDTR double transgenic mice expressing Cre recombinase in oligodendrocytes, we observed myelin loss after intraperitoneal DT injections. Thus, DT crosses the blood-brain bar…
Cdc42 in osterix-expressing cells alters osteoblast behavior and myeloid lineage commitment
2021
Osteoblasts are not only responsible for bone formation. They also support hematopoiesis. This requires responding to cues originating from several signaling pathways, a task performed by Rho GTPases. We therefore examined several transgenic mouse models and used inhibitors of Cdc42 in vitro. Deletion of Cdc42 in vivo using the Osterix promoter suppressed osteoblast function, while its deletion in differentiating osteoblasts using the Collagen-a1(I) promoter decreased osteoblast numbers. In both cases, bone mineral density diminished confirming the importance of Cdc42. Evaluation of hematopoiesis revealed that deletion of Cdc42 using the Osterix, but not the Collagen-a1(I) promoter increase…
Molecular evidence for the presence of cryptic evolutionary lineages in the freshwater copepod genus Hemidiaptomus G.O. Sars, 1903 (Calanoida, Diapto…
2010
The pattern of morphological and mtDNA cytochrome b diversity of three calanoid copepod species belonging to the diaptomid genus Hemidiaptomus has been investigated with the aim of checking the reliability of the morphological characters currently used for species identification, and the possible presence of cryptic taxa. A sharply different molecular structuring has been observed in the studied species: while Hemidiaptomus amblyodon exhibits a remarkable constancy throughout the European range of its distribution area (maximum inter-populations cytochrome b divergence of 3%), observed distances between presumed conspecific lineages of Hemidiaptomus gurneyi (maximum divergence of 21.5%) and…
Epigenetic and in vivo comparison of diverse MSC sources reveals an endochondral signature for human hematopoietic niche formation
2015
In the last decade there has been a rapid expansion in clinical trials using mesenchymal stromal cells (MSCs) from a variety of tissues. However, despite similarities in morphology, immunophenotype, and differentiation behavior in vitro, MSCs sourced from distinct tissues do not necessarily have equivalent biological properties. We performed a genome-wide methylation, transcription, and in vivo evaluation of MSCs from human bone marrow (BM), white adipose tissue, umbilical cord, and skin cultured in humanized media. Surprisingly, only BM-derived MSCs spontaneously formed a BM cavity through a vascularized cartilage intermediate in vivo that was progressively replaced by hematopoietic tissue…
Mechanisms underlying lineage commitment and plasticity of human γδ T cells.
2012
Phenotypic and functional heterogeneity are the hallmarks of effector and memory T cells. Upon antigen stimulation, γδ T cells differentiate into two major types of memory T cells: central memory cells, which patrol the blood and secondary lymphoid organs, and effector memory cells, which migrate to peripheral tissues. γδ T cells display in vitro a certain degree of plasticity in their function that is reminiscent of that which is observed in conventional CD4 T cells. Similar to CD4 T cells, in which a plethora of specialized subsets affect the host response, γδ T cells may readily and rapidly assume distinct Th1-, Th2-, Th17-, T(FH) and T regulatory-like effector functions, suggesting that…
Differentiation of Effector/Memory Vδ2 T Cells and Migratory Routes in Lymph Nodes or Inflammatory Sites
2003
Vδ2 T lymphocytes recognize nonpeptidic antigens without presentation by MHC molecules and mount both immediate effector functions and memory responses after microbial infection. However, how Vδ2 T cells mediate different facets of a memory response remains unknown. Here, we show that the expression of CD45RA and CD27 antigens defines four subsets of human Vδ2 T cells with distinctive compartmentalization routes. Naive CD45RA+CD27+ and memory CD45RA−CD27+ cells express lymph node homing receptors, abound in lymph nodes, and lack immediate effector functions. Conversely, memory CD45RA−CD27− and terminally differentiated CD45RA+CD27− cells, which express receptors for homing to inflamed tissu…
The evolution of the heat-shock protein GroEL from Buchnera, the primary endosymbiont of aphids, is governed by positive selection
2002
The heat-shock protein GroEL is a double-ring-structured chaperonin that assists the folding of many newly synthesized proteins in Escherichia coli and the refolding in vitro, with the cochaperonin GroES, of conformationally damaged proteins. This protein is constitutively overexpressed in the primary symbiotic bacteria of many insects, constituting approximately 10% of the total protein in Buchnera, the primary endosymbiont of aphids. In the present study, we perform a maximum likelihood (ML) analysis to unveil the selective constraints in GroEL. In addition, we apply a new statistical approach to determine the patterns of evolution in this highly interesting protein. The main conclusion d…
Expression and function of micro-RNAs in immune cells during normal or disease state.
2008
Micro-RNAs (miRNAs) are 19-24 nucleotide long non-coding RNAs that posttranscriptionally modulate gene expression. They are found in almost all species: viruses, plants, nematodes, fly, fish, mouse, human, and are implicated in a wide array of cellular and developmental processes. Microarray-based miRNA profiling brought to the discovery of miRNAs specific to different hematopoietic lineages. Furthermore, the functional assays performed in tissue cultures to discover miRNAs involved in immune responses in combination with the reports of miRNA-transgenic or miRNA -knockout mouse models has helped elucidating the miRNA roles in the development and function of immune system. Abnormal patterns …
Delayed healing of chronic leg ulcers can result from impaired trafficking of bone marrow-derived precursors of keratinocytes to the skin
2006
In this paper, it is hypothesized that in chronic wounds the process of homing of bone marrow-derived precursors of keratinocytes is disturbed, and that the interaction between cutaneous T-cell attracting chemokine (CTACK/CCL27) and soluble P-selectin glycoprotein ligand-1 (PSGL-1) can be the cause of this impairment. Several studies have revealed that bone marrow-derived cells (BMDC) trans-differentiate into various cellular lineages, and probably they participate also in healing of wounded skin. Recent studies have demonstrated that BMDC can engraft into the epidermis, and probably they do not engraft into epidermis as keratinocyte stem cells, but rather as transient amplifying cells. So,…
Multicolor fate mapping of Langerhans cell homeostasis
2013
The adult epidermal Langerhans cell network is formed by adjacent proliferative units composed of dividing cells and their terminally differentiated daughter cells.