ABSTRACT
The incidence of inflammatory bowel diseases has increased during recent decades. Within the colon, the families of mucins (MUC) and trefoil factors (TFF) facilitate mucosal protection. Probiotic administration influences the intestinal MUC layer. Additionally, food components may affect gut microflora or have direct effects on the MUC barrier. Our objective was to determine whether diet and/or Lactobacillus rhamnosus GG (LGG) would mediate dextran sodium sulfate (DSS)-induced colitis by altering expression of the MUC and TFF genes. C57BL/6 mice were fed diets containing 20% (wt:wt) casein, soy, or whey proteins with or without LGG for 12 d. Seven days after starting LGG diets, the mice were given 2% DSS in drinking water for 4 d. Two additional casein groups with or without LGG were given tap water, for a total of 8 groups. One day after the DSS treatment, the mice were killed and the colon and cecum tissues and cecum contents were collected and analyzed by qRT-PCR. Whey protein significantly increased cecal LGG content compared with the other diets. In the casein diet groups, MUC1 and TFF-3 expression in colon was significantly induced by DSS independent of LGG. Compared with other DSS-treated groups, soy protein decreased MUC-1 and TFF-3 in the colon. Similarly, soy protein decreased the impact of DSS on inflammatory scores, TNFα gene expression, and colon shortening. There was no overall effect of LGG on these measurements. In conclusion, soy protein suppressed the DSS-induced inflammatory stimulation of MUC, TFF, and TNFα gene expression independently of LGG.
Subject(s)
Colitis, Ulcerative/diet therapy , Colitis, Ulcerative/genetics , Lacticaseibacillus rhamnosus , Mucin-1/genetics , Mucins/genetics , Probiotics/administration & dosage , Soybean Proteins/administration & dosage , Tumor Necrosis Factor-alpha/genetics , Animals , Base Sequence , Caseins/administration & dosage , Cecum/metabolism , Cecum/microbiology , Colitis, Ulcerative/chemically induced , Colitis, Ulcerative/therapy , Colon/metabolism , Colon/microbiology , Dextran Sulfate/toxicity , Disease Models, Animal , Female , Gene Expression , Mice , Mice, Inbred C57BL , Milk Proteins/administration & dosage , RNA, Messenger/genetics , RNA, Messenger/metabolism , Trefoil Factor-3 , Whey ProteinsABSTRACT
Dietary energy restriction (DER, 40% calorie reduction from fat and carbohydrate) inhibited mouse skin carcinogenesis and decreased 12-O-tetradecanoyl-13-phorbol acetate (TPA)-induced activator protein-1 (AP-1):DNA binding previously. This study measured protein levels of c-jun, jun B, jun D, c-fos, fra-1, and fra-2 and examined their contribution to AP-1:DNA binding by electrophoretic mobility shift assay (EMSA) with supershift analysis in the epidermis of control and DER Sencar mice exposed to TPA. TPA significantly increased c-jun, jun B, c-fos, fra-1, and fra-2 and decreased jun D within 3-6 h after treatment. AP-1:DNA binding reached a maximum 2.5-fold induction over controls 4 h after TPA treatment and antibodies to jun B, jun D, and fra-2 in the EMSA binding reaction resulted in supershifts in both acetone- and TPA-treated mice 1-6 h after treatment. The effect of corticosterone (CCS) and DER on the AP-1 proteins and on the composition of the AP-1:DNA complex was measured in adrenalectomized (adx) mice. DER reduced the TPA impact on jun D and enhanced the induction of fra-1. In addition, CCS-supplemented groups had significantly lower jun D and higher fra-2 than adx groups and sham groups. While sham animals treated with either acetone or TPA contained jun B, jun D, and fra-2 proteins in the AP-1:DNA complex by supershift analysis, fra-2 was no longer seen in adx DER animals. In summary, our study supports potential roles for jun D, jun B, and fra-1 in the DER regulation of AP-1 function in the Sencar mouse skin carcinogenesis model.
Subject(s)
Caloric Restriction , Epidermis/drug effects , Glucocorticoids/metabolism , Proto-Oncogene Proteins c-fos/metabolism , Proto-Oncogene Proteins c-jun/metabolism , Skin Neoplasms/prevention & control , Animals , Body Weight , Corticosterone/metabolism , DNA/metabolism , Epidermis/pathology , Female , Mice , Mice, Inbred SENCAR , Protein Binding/drug effects , Skin/drug effects , Skin/pathology , Skin Neoplasms/chemically induced , Skin Neoplasms/metabolism , Tetradecanoylphorbol Acetate , Transcription Factor AP-1/metabolismABSTRACT
The study examined the timing of modulation of activator protein 1(AP-1):DNA binding and production of AP-1 constituent proteins by ultraviolet B (UVB) radiation and effect of dietary energy restriction [DER, 40% calorie reduction from fat and carbohydrate compared to control ad libitum (AL) diet] in SKH-1 mouse epidermis. AP-1:DNA binding by electromobility shift assay (EMSA) was increased in a biphasic manner after treatment with a tumor-promoting suberythemal dose (750 mJ/cm(2)) of UVB light (311-313 nm) with peaks at 3 and 18 h postirradiation. DER overall reduced AP-1:DNA binding in mock-treated and UVB-treated skin at 3 and 18 h after UVB treatment. The timing of modulation of production of AP-1 constituent proteins by Western blot analysis was examined at 0 h (mock treatment), 3, 9, 18, and 24 h. We found that c-jun (9 h), jun-B (9 and 18 h), phosphorylated c-jun (3 h), and fra-1 (18 h) protein levels were increased after UVB treatment compared to mock controls. In a follow-up diet experiment, animals were placed on DER or AL diet for 10-12 wk and treated with UVB as before. DER was found to completely block the UVB-induced increase in phosphorylated c-jun protein levels and decrease in fra-2 protein levels at 18 h. In addition, DER enhanced UVB-induced increase in jun B levels and lowered basal levels of c-fos seen 18 h after UVB. These data suggest that DER may be able to assist in the prevention of UVB-induced skin carcinogenesis by modulating AP-1:DNA binding and AP-1 constituent protein levels.
