Journal: MedComm

Article Title: Nitrate Enhances Gastric Mucosa Defense and Repair Process in Ethanol‐Induced Gastric Ulcer Rats via the Notch–Tff2 Pathway

doi: 10.1002/mco2.70628

Figure Lengend Snippet: Nitrate functions by Notch pathway inhibition positively transcripting TFF2 in vitro. (A) Diagram of the wild‐type and mutant sequences for the three predicted RBPJ binding sites within the 251 bp TFF2 promoter probes. (B) Representative electrophoretic mobility shift assay (EMSA) autoradiograph. Hot probe is the biotin‐labeled wild‐type oligonucleotides of the truncated TFF2 promoter containing the binding motif; Mutant probe is the labeled oligonucleotides sequence with nucleotides mutated. The cold probe is nonlabeled competitive wild‐type probes (100 and 50 that of the concentrations). The shifted bands are indicated by arrows, which suggested the formation of DNA–protein complexes (lane 2, 3, 7). The super shifted bands indicated the formation of DNA–protein–antibody complexes (lane 3, 7). “+” and “−” represent presence and absence, respectively. (C) Relative TFF2 promoter (Full, Mut1, Mut2, and Mut3) luciferase activity was detected by DLR assays in RBPJ overexpressed and normal‐expressed GES‐1 cells. (D) A schematic diagram showing the location of RBPJ putative binding regions on the TFF2 promoter. (E) RT‐qPCR analysis of TFF2 binding site expression of GES‐1 cells. Target site expression in RBPJ‐treated groups was normalized to IgG negative control groups and expressed as fold change relative to the IgG groups. (F) IF staining of NICD (pink) and DAPI (blue). Scale bar = 50 µm. (G) IF analysis of MFI of nuclear NICD in positive cells. (H) Representative immunoblotting band of Notch signaling pathway in GES‐1 cells. (I–K) Analyses of immunoblotting band gray value of (H). (L) RT‐qPCR analysis of TFF2 mRNA expression of DMSO/DAPT treated GES‐1 cells. Target gene expression was normalized to GAPDH mRNA and expressed as fold change relative to the DMSO vehicle group. (M) RT‐qPCR analysis of TFF2 mRNA expression in RBPJ overexpressed and NICD deprived GES‐1 cells. The target gene expression was normalized to GAPDH mRNA and expressed as fold change relative to the vector + DMSO group. (N) RT‐qPCR analysis of TFF2 mRNA expression in RBPJ overexpressed and NICD‐RBPJ overexpressed GES‐1 cells. The target gene expression was normalized to GAPDH mRNA and expressed as fold change relative to the vector1 + vector2 group. (O) Representative image of PLA of NICD–RBPJ proximity. Each red dot represents a positive signal of NICD–RBPJ interaction and nuclei were counterstained with DAPI (blue). Scale bar = 20 µm. Quantitative data are expressed as the mean ± SD. * p < 0.05, ** p < 0.01, *** p < 0.001, and ns denotes no significance. Nit, nitrate; EtOH, ethanol; GES‐1, human gastric epithelial; NICD, intracellular structural domain; RBPJ, recombination signal binding protein for immunoglobulin kappa J region; EMSA, electrophoretic mobility shift assay; TFF2, trefoil factor 2; DAPI, 2‐(4‐amidinophenyl)‐6‐indolecarbamidine dihydrochloride; Yhhu‐3792, N2‐(4‐isopropylphenyl)‐5‐(3‐methoxyphenoxy) quinazoline‐2,4‐diamine; Luc, luciferase; SD, standard deviation; DLR, dual‐luciferase report; PLA, proximity ligation assay.

Article Snippet: The probes were incubated with the GES‐1 cells extract and RBPJ antibody (5313; Cell Signaling Technology, USA) at room temperature for 50 min. To comprehend the specificity of the DNA/protein binding reactions, competition assays were performed with 50/100 excessive unlabeled cold probes.

Techniques: Inhibition, In Vitro, Mutagenesis, Binding Assay, Electrophoretic Mobility Shift Assay, Autoradiography, Labeling, Sequencing, Luciferase, Activity Assay, Quantitative RT-PCR, Expressing, Negative Control, Staining, Western Blot, Targeted Gene Expression, Plasmid Preparation, Standard Deviation, Proximity Ligation Assay