L Cells were cultured for 3 days before transfection: SilenceMag was mixed with siRNA (final concentration 20 to 50 nmol/L and incubated for 20 min at 37°C and complexes were added onto L Cells for 15 min on a magnetic plate.
This article highlights the capacity of Magnetofection technology to
efficiently silence gene expression into primary epithelial cells with
siRNA using SilenceMag from OZ Biosciences.
article reference: Am J Pathol, 2014, doi:10.1016/j.ajpath.2014.09.010
Tumor Necrosis Factor α Decreases Glucagon-Like Peptide-2 Expression by Up-Regulating G-Protein–Coupled Receptor 120 in Crohn Disease
Takuya Tsukahara, Kenji Watanabe, Toshio Watanabe, Hirokazu Yamagami, Mitsue Sogawa, Tetsuya Tanigawa, Masatsugu Shiba, Kazunari Tominaga, Yasuhiro Fujiwara, Kiyoshi Maeda, Kosei Hirakawa, Tetsuo Arakawa,
Abstract
Glucagon-like peptide (GLP)-2, secreted by L cells in the small
intestine, has anti-inflammatory effects in the gastrointestinal tract. A
GLP-2 analogue has been an effective treatment for Crohn disease (CD).
G-protein–coupled receptor (GPR) 40 and GPR120 are probably involved in
GLP-2 production, the mechanisms of which remain unclear. In our
experiments, normal ileal mucosa expressed GPR40, but rarely expressed
GPR120. However, both GPRs were overexpressed in the L cells of the
inflamed ileal mucosa of CD patients. Mucosal inflammation induced the
overexpression of GPR40, GPR120, and several inflammatory cytokines,
with correlations between ileal concentrations of tumor necrosis factor
(TNF)-α and GPR expression levels; however, inflammation did not induce
the expression of proglucagon, a precursor of GLP-2 in CD patients. In
rat L cells and GLUTag cells, TNF-α treatment increased GPR120 mRNA
expression without affecting GPR40 mRNA expression. Dual agonists of
GPR40 and GPR120, GW9508 and linoleic acid, respectively, increased
GLP-2 production from L cells, but these agonists decreased it in the
presence of TNF-α. The GPR40 antagonist, GW1100, inhibited the
GW9508-induced increase in GLP-2 production, and silencing GPR120
resulted in further elevation of GLP-2 production. Thus,
GPR120-dependent signaling inhibited the stimulatory effects of GPR40 on
GLP-2 expression, and TNF-α treatment decreased GLP-2 expression by
up-regulating GPR120 expression in L cells.
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