Search results for "Intestines"
showing 10 items of 177 documents
Link between Intestinal CD36 Ligand Binding and Satiety Induced by a High Protein Diet in Mice
2012
International audience; CD36 is a ubiquitous membrane glycoprotein that binds long-chain fatty acids. The presence of a functional CD36 is required for the induction of satiety by a lipid load and its role as a lipid receptor driving cellular signal has recently been demonstrated. Our project aimed to further explore the role of intestinal CD36 in the regulation of food intake. Duodenal infusions of vehicle or sulfo-N-succinimidyl-oleate (SSO) was performed prior to acute infusions of saline or Intralipid (IL) in mice. Infusion of minute quantities of IL induced a decrease in food intake (FI) compared to saline. Infusion of SSO had the same effect but no additive inhibitory effect was obser…
Activated glycoprotein A repetitions predominant (GARP)-expressing regulatory T cells inhibit allergen-induced intestinal inflammation in humanized m…
2015
Background Recently, we developed a humanized mouse model of allergen-induced IgE-dependent gut inflammation in PBMC-engrafted immunodeficient mice. Objective In the present study, we wanted to investigate the role of regulatory T (Treg) cells and their activation status in this model. Methods Nonobese diabetic-severe combined immunodeficiency-γc −/− mice were injected intraperitoneally with human PBMCs from allergic donors together with the respective allergen or NaCl as control in the presence or absence of different concentrations of CD4 + CD25 + Treg cells of the same donor. After an additional allergen boost 1 week later, mice were challenged with the allergen rectally on day 21 and gu…
Maintenance of the intestinal tube in Caenorhabditis elegans: the role of the intermediate filament protein IFC-2.
2008
The Caenorhabditis elegans intestinal lumen is surrounded by a dense cytoplasmic network that is laterally attached to the junctional complex and is referred to as the endotube. It localizes to the terminal web region which anchors the microvillar actin filament bundles and is particularly rich in intermediate filaments. To examine their role in intestinal morphogenesis and function, C. elegans reporter strains were generated expressing intestine-specific CFP-tagged intermediate filament polypeptide IFB-2. When these animals were treated with dsRNA against intestinal intermediate filament polypeptide IFC-2, the endotube developed multiple bubble-shaped invaginations that protruded into the …
The human gene encoding cytokeratin 20 and its expression during fetal development and in gastrointestinal carcinomas
1993
The differentiation of the predominant cell types of the mucosal epithelium of the mammalian gastrointestinal tract is characterized by increasing amounts of an intermediate-sized filament (IF) protein designated cytokeratin (CK) 20 which is a major cellular protein of mature enterocytes and goblet cells. Here we report the isolation of the human gene encoding CK 20, its complete nucleotide sequence and the amino acid sequence deduced therefrom that identifies this polypeptide (mol. wt. 48553) as a member of the type I-CK subfamily. Remarkable, however, is the comparably great sequence divergence of CK 20 from all other known type I-CKs, with only 58% identical amino acids in the conserved …
Mammalian intestinal alkaline phosphatase acts as highly active exopolyphosphatase.
2001
Recent results revealed that inorganic polyphosphates (polyP), being energy-rich linear polymers of orthophosphate residues known from bacteria and yeast, also exist in higher eukaryotes. However, the enzymatic basis of their metabolism especially in mammalian cells is still uncertain. Here we demonstrate for the first time that alkaline phosphatase from calf intestine (CIAP) is able to cleave polyP molecules up to a chain length of about 800. The enzyme acts as an exopolyphosphatase degrading polyP in a processive manner. The pH optimum is in the alkaline range. Divalent cations are not required for catalytic activity but inhibit the degradation of polyP. The rate of hydrolysis of short-ch…
Optimization of the Ussing chamber setup with excised rat intestinal segments for dissolution/permeation experiments of poorly soluble drugs.
2016
AbstractContext: Prediction of the in vivo absorption of poorly soluble drugs may require simultaneous dissolution/permeation experiments. In vivo predictive media have been modified for permeation experiments with Caco-2 cells, but not for excised rat intestinal segments.Objective: The present study aimed at improving the setup of dissolution/permeation experiments with excised rat intestinal segments by assessing suitable donor and receiver media.Methods: The regional compatibility of rat intestine in Ussing chambers with modified Fasted and Fed State Simulated Intestinal Fluids (Fa/FeSSIFmod) as donor media was evaluated via several parameters that reflect the viability of the excised in…
Epithelial NEMO links innate immunity to chronic intestinal inflammation
2007
Deregulation of intestinal immune responses seems to have a principal function in the pathogenesis of inflammatory bowel disease(1-4). The gut epithelium is critically involved in the maintenance of intestinal immune homeostasis-acting as a physical barrier separating luminal bacteria and immune cells, and also expressing antimicrobial peptides(3,5,6). However, the molecular mechanisms that control this function of gut epithelial cells are poorly understood. Here we show that the transcription factor NF kappa B, a master regulator of pro-inflammatory responses(7,8), functions in gut epithelial cells to control epithelial integrity and the interaction between the mucosal immune system and gu…
Tolerance towards resident intestinal flora in mice is abrogated in experimental colitis and restored by treatment with interleukin-10 or antibodies …
1996
There is now increasing evidence that hyperresponsiveness towards intestinal flora is a crucial event in the pathogenesis of inflammatory bowel disease (IBD). In support of this hypothesis, we recently described in humans that tolerance exists towards indigenous intestinal flora but is broken in active IBD lesions. In the present study, we have attempted to transfer this model into mice from different genetic backgrounds (BALB/c, SJL/J, C3H/HeJ). We found that mononuclear cells from spleen, small bowel and large bowel of mice do not proliferate, i.e. are tolerant when exposed to bacterial sonicates derived from autologous intestine (BsA) but do proliferate, i.e. are immune when exposed to b…
Midgut microbiota and host immunocompetence underlie Bacillus thuringiensis killing mechanism
2016
Bacillus thuringiensis is a widely used bacterial entomopathogen producing insecticidal toxins, some of which are expressed in insect-resistant transgenic crops. Surprisingly, the killing mechanism of B. thuringiensis remains controversial. In particular, the importance of the septicemia induced by the host midgut microbiota is still debated as a result of the lack of experimental evidence obtained without drastic manipulation of the midgut and its content. Here this key issue is addressed by RNAi-mediated silencing of an immune gene in a lepidopteran host Spodoptera littoralis, leaving the midgut microbiota unaltered. The resulting cellular immunosuppression was characterized by a reduced …
Definition of the single integration site of the pathogenicity locus in Clostridium difficile.
1996
We determined the nucleotide sequence 3.8 kb upstream and 5.2 kb downstream of the toxin genes A and B of Clostridium difficile. Nine ORFs were discovered. Based on PCR-directed approaches, two were attributed to the pathogenicity locus (PaLoc). The other seven were found in every C. difficile isolate obtained from the human gastrointestinal tract, respectless of their toxinogenicity. The ORFs cdu1 and cdu2/2' upstream of the PaLoc displayed similarity to repressors of Gram-positive bacteria (cdu1), and to an Na+/H+ antiporter described for Enterococcus hirae (cdu2/2'). Downstream of the locus a putative ABC transporter (cdd2-4) was identified. With a set of three paired primers used in pol…