ABSTRACT
To investigate the effects of miR-31 on TLR4/NF-κB signaling pathway and
apoptosis-related
proteins in
dextran sulfate sodium (DSS) induced
mouse colon colitis.
Methods:
①
Mouse model of
colon colitis 1% DSS was used to induce
mouse ulcerative colitis (UC). Fourteen FVB non-
transgenic mice were randomly divided into
control group (n= 6), DSS group (n= 8), and 16 FVB miR-31
transgenic mice were randomly divided into miR-31 overexpression group (n= 8), miR-31 overexpression +DSS group (n= 8). DSS was dissolved in
water and administered to
mice by
drinking water. The DSS group and miR-31+DSS group drank 1% DSS
water in the first week, normal
sterilized water in the second week, and 1% DSS
water in the third week, after 5 weeks, the modeling was completed, then the
colon tissues of the
mice were collected.
Western blot and IHC were used to detect the expressions of NF-κB p65, TLR4, Bax and Bcl-2
proteins in
mouse colon tissue,
TUNEL was used to detect
apoptosis of
mouse colon tissues. ②
Cell culture experiments
Transfection of miR-31mimic and inhibitor by lipofectamine resulted in overexpression or knockdown of miR-31 in
human colon epithelial cell line
HCT 116 cells, each group was repeated three times and
cells were collected 48 h later,
Western blot was used to detect the expressions of NF-κB p65 and TLR4
protein. ① In
animal experiments, compared with the
control group, the expression levels of NF-κB p65, TLR4
protein and apoptotic
cell index in the DSS group and miR-31 overexpression group in
mouse colon tissue were significantly increased (P<0.05 or P<0.01), and the Bcl-2 / Bax ratio was significantly reduced (P<0.05 or P<0.01); and compared with the DSS group, the expression levels of NF-κB p65, TLR4
protein and apoptotic
cell index in the miR-31+DSS group were significantly increased (P<0.01), while the Bcl-2/Bax ratio was significantly decreased (P<0.01). ② In
cell experiments, compared with the
control group, the expression levels of NF-κB p65 and TLR4
protein in the over-expressed miR-31 group of
HCT 116 cells were significantly increased (P<0.05 or P<0.01), the expressions of NF-κB p65 and TLR4
protein in miR-31 knockdown group were decreased (P<0.05). miR-31 promotes the development of
colitis by promoting TLR4/NF-κB signaling pathway and
mediating apoptosis of intestinal
epithelial cells.