44 research outputs found
Integrative mapping analysis of chicken microchromosome 16 organization
<p>Abstract</p> <p>Background</p> <p>The chicken karyotype is composed of 39 chromosome pairs, of which 9 still remain totally absent from the current genome sequence assembly, despite international efforts towards complete coverage. Some others are only very partially sequenced, amongst which microchromosome 16 (GGA16), particularly under-represented, with only 433 kb assembled for a full estimated size of 9 to 11 Mb. Besides the obvious need of full genome coverage with genetic markers for QTL (Quantitative Trait Loci) mapping and major genes identification studies, there is a major interest in the detailed study of this chromosome because it carries the two genetically independent <it>MHC </it>complexes <it>B </it>and <it>Y</it>. In addition, GGA16 carries the ribosomal RNA (<it>rRNA</it>) genes cluster, also known as the <it>NOR </it>(nucleolus organizer region). The purpose of the present study is to construct and present high resolution integrated maps of GGA16 to refine its organization and improve its coverage with genetic markers.</p> <p>Results</p> <p>We developed 79 STS (Sequence Tagged Site) markers to build a physical RH (radiation hybrid) map and 34 genetic markers to extend the genetic map of GGA16. We screened a BAC (Bacterial Artificial Chromosome) library with markers for the <it>MHC-B</it>, <it>MHC-Y </it>and <it>rRNA </it>complexes. Selected clones were used to perform high resolution FISH (Fluorescent <it>In Situ </it>Hybridization) mapping on giant meiotic lampbrush chromosomes, allowing meiotic mapping in addition to the confirmation of the order of the three clusters along the chromosome. A region with high recombination rates and containing PO41 repeated elements separates the two <it>MHC </it>complexes.</p> <p>Conclusions</p> <p>The three complementary mapping strategies used refine greatly our knowledge of chicken microchromosome 16 organisation. The characterisation of the recombination hotspots separating the two <it>MHC </it>complexes demonstrates the presence of PO41 repetitive sequences both in tandem and inverted orientation. However, this region still needs to be studied in more detail.</p
Role of Eosinophils in Inflammatory Bowel and Gastrointestinal Diseases
Inflammatory bowel diseases (IBD) are characterized by the invasion of
leukocytes into the intestinal mucosa. However, a mixed inflammatory
picture is observed that includes neutrophils, lymphocytes, monocytes,
and eosinophils. To this day, the role of eosinophils in health and in disease
remains unclear. Investigations into their function stem primarily from
allergic diseases, asthma, and parasitic infections. This makes it even more
difficult to discern a role for the fascinating eosinophil in IBDs because,
unlike the lung or the skin, eosinophils reside in normal intestinal mucosa
and increase in disease states; consequently, an intricate system must
regulate their migration and numbers. These granulocytes are equipped
with the machinery to participate in gastrointestinal (GI) inflammation and
in the susceptible microenvironment, they may initiate or perpetuate an
inflammatory response. A significant body of literature characterizes eosinophils present in the GI microenvironment where they have the potential to
interact with other resident cells, thus promoting intestinal remodeling,
mucus production, epithelial barrier, cytokine production, angiogenesis, and
neuropeptide release. A number of lines of evidence support both potential
beneficial and deleterious roles of eosinophils in the gut. Although studies
from the gut and other mucosal organs suggest eosinophils affect mucosal GI
inflammation, definitive roles for eosinophils in IBDs await discovery
CCR3 Blockade Attenuates Eosinophilic Ileitis and Associated Remodeling
Intestinal remodeling and stricture formation is a complication of inflammatory bowel disease (IBD) that often requires surgical intervention. Although eosinophils are associated with mucosal remodeling in other
organs and are increased in IBD tissues, their role in
IBD-associated remodeling is unclear. Histological and
molecular features of ileitis and remodeling were assessed using immunohistochemical, histomorphometric, flow cytometric, and molecular analysis (real-time
RT-PCR) techniques in a murine model of chronic eosinophilic ileitis. Collagen protein was assessed by Sircol
assay. Using a spontaneous eosinophilic Crohn’s-like
mouse model SAMP1/SkuSlc, we demonstrate an association between ileitis progression and remodeling over
the course of 40 weeks. Mucosal and submucosal eosinophilia increased over the time course and correlated
with increased histological inflammatory indices. Ileitis
and remodeling increased over the 40 weeks, as did
expression of fibronectin. CCR3-specific antibody-mediated reduction of eosinophils resulted in significant decrease in goblet cell hyperplasia, muscularis propria
hypertrophy, villus blunting, and expression of inflammatory and remodeling genes, including fibronectin.
Cellularity of local mesenteric lymph nodes, including
T- and B-lymphocytes, was also significantly reduced.
Thus, eosinophils participate in intestinal remodeling, supporting eosinophils as a novel therapeutic
target
Esophageal human β-defensin expression in eosinophilic esophagitis.
Background: Defensins are antimicrobial peptides
expressed on mucosal surfaces that contribute to maintaining
intestinal homeostasis by providing innate defense mechanisms for the epithelia. Defensin expression is altered in a number of diseases that affect mucosal surfaces, such as atopic
dermatitis, allergic rhinitis, and inflammatory bowel disease.
Similar to atopic dermatitis, eosinophilic esophagitis (EoE) is
a chronic disease in which the squamous epithelial surface is
affected by a similar TH2 microenvironment and eosinophilpredominant inflammation. Therefore, we hypothesized that
defensin expression would be decreased in EoE.
Methods: To address this, we measured defensin expression
invitro in cell lines derived from patients with EoE (EoE1-T) or gastroesophageal reflux disease (GERD) (NES-G4T cells) and ex vivo
in esophageal mucosal biopsy samples from children with EoE
or GERD and control children without esophageal disease.
Results: Interleukin-5 induced a decrease in human
β-defensin (hBD) -1 and hBD3 expression in EoE1-T but not in
NES-G4T cells. Compared with esophageal biopsy specimens
from GERD and control children, specimens from EoE pediatric
patients revealed a significant decrease in mRNA and protein
expression for hBD1 and hBD3.
Conclusion: Diminished expression of hBD1 and hBD3
may make the esophageal epithelium more susceptible to the
development and/or perpetuation of EoE
S1070 Identification of Epithelial Mesenchymal Transition in Eosinophilic Esophagitis and Its Relationship to Esophageal Remodeling and Fibrosis
Local hypersensitivity reaction in transgenic mice with squamous epithelial IL-5 overexpression provides a novel model of eosinophilic oesophagitis
Objective: Eosinophilic oesophagitis (EoE) is a chronic
inflammatory condition of the oesophagus with limited
treatment options. No previous transgenic model has
specifically targeted the oesophageal mucosa to induce
oesophageal eosinophilia.
Design: We developed a mouse model that closely
resembles EoE by utilising oxazolone haptenation in mice
with transgenic overexpression of an eosinophil poietic
and survival factor (interleukin (IL)-5) in resident
squamous oesophageal epithelia.
Results: Overexpression of IL-5 in the healthy
oesophagus was achieved in transgenic mice (L2-IL5)
using the squamous epithelial promoter Epstein–Barr
virus ED-L2. Oxazolone-challenged L2-IL5 mice
developed dose-dependent pan-oesophageal
eosinophilia, including eosinophil microabscess formation
and degranulation as well as basal cell hyperplasia.
Moreover, oesophagi expressed increased IL-13 and the
eosinophil agonist chemokine eotaxin-1. Treatment of
these mice with corticosteroids significantly reduced
eosinophilia and epithelial inflammation.
Conclusions: L2-IL5 mice provide a novel experimental
model that can potentially be used in preclinical testing
of EoE-related therapeutics and mechanistic studies
identifying pathogenetic features associated with
mucosal eosinophilia