Gut-derived Endotoxin-TLR4 Signaling Drives MYC-Ig Translocation to Promote Lymphoproliferation through c-JUN and STAT3 Activation.

Synergism between obesity and virus infection promotes the development of B-cell lymphoma. In this study, we tested whether obesity-associated endotoxin release induced activation-induced cytidine deaminase (AID). TLR4 activation in turn caused c-JUN-dependent and STAT3-dependent translocations of MYC loci to suppress transactivation of CD95/FAS. We used viral nucleocapside Core transgenic (Tg) mice fed alcohol Western diet to determine whether oncogenesis arising from obesity and chronic virus infection occurred through TLR4-c-JUN-STAT3 pathways. Our results showed B cell-specific, c-Jun and/or Stat3 disruption reduced the incidence of splenomegaly in these mice. AID-dependent t(8;14) translocation was observed between the Ig promoter and MYC loci. Comparison with human B cells showed MYC-immunoglobulin (Ig) translocations after virus infection with lipopolysaccharide stimulation. Accordingly, human patients with lymphoma with virus infections and obesity showed a 40% incidence of MYC-Ig translocations. Thus, obesity and virus infection promote AID-mediated translocation between the Ig promoter and MYC through the TLR4-c-JUN axis, resulting in lymphoproliferation. Taken together, preventative treatment targeting either c-JUN and/or STAT3 may be effective strategies to prevent tumor development. IMPLICATIONS: Obesity increases gut-derived endotoxin which induces Toll-like receptor-mediated MYC-Ig translocation via c-JUN-STAT3, leading to lymphoproliferation.

Rebamipide suppresses diclofenac-induced intestinal permeability via mitochondrial protection in mice.

AIM: To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice. METHODS: Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally. A control group received the vehicle by gavage. Rebamipide (100 mg/kg, 200 mg/kg, 400 mg/kg) was administered intragastrically once a day for 3 d 4 h after diclofenac administration. Intestinal permeability was evaluated by Evans blue and the FITC-dextran method. The ultrastructure of the mucosal barrier was evaluated by transmission electron microscopy (TEM). Mitochondrial function including mitochondrial swelling, mitochondrial membrane potential, mitochondrial nicotinamide adenine dinucleotide-reduced (NADH) levels, succinate dehydrogenase (SDH) and ATPase activities were measured. Small intestinal mucosa was collected for assessment of malondialdehyde (MDA) content and myeloperoxidase (MPO) activity. RESULTS: Compared with the control group, intestinal permeability was significantly increased in the diclofenac group, which was accompanied by broken tight junctions, and significant increases in MDA content and MPO activity. Rebamipide significantly reduced intestinal permeability, improved inter-cellular tight junctions, and was associated with decreases in intestinal MDA content and MPO activity. At the mitochondrial level, rebamipide increased SDH and ATPase activities, NADH level and decreased mitochondrial swelling. CONCLUSION: Increased intestinal permeability induced by diclofenac can be attenuated by rebamipide, which partially contributed to the protection of mitochondrial function.

[Significance of plasmic homocysteine, folate and Vitamin B(12) in ulcerative colitis].

OBJECTIVE: To investigate the clinical significance of plasmic homocysteine (Hcy), folate (FA) and Vitamin B(12) (VitB(12)) in patients with ulcerative colitis (UC). METHODS: Plasmic Hcy in 112 cases of UC patients and 110 controls were detected by HPLC-FD method. Plasmic FA, VitB(12) in 76 cases of UC patients and 12 controls were detected by enzyme-linked immunosorbent assay (ELISA) method. RESULTS: The level of plasmic Hcy in UC patients was(11.27±7.26) µmol/L, significantly higher than that in controls[(8.19±4.81) µmol/L, P<0.05], and was not significantly correlated with disease index, extent and duration of UC(P>0.05). The level of FA and VitB(12) in UC patients were (7.64±1.95) nmol/L and (108.64±32.22) pmol/L respectively, lower than those in controls[(9.14±1.23) nmol/L and (112.64±33.33) pmol/L, P<0.05]. The level of plasmic Hcy was negatively correlated with the level of FA and VitB(12) in UC patients(P<0.05). The level of plasmic FA decreased to some extent with UC disease duration. CONCLUSION: Plasmic Hcy is elevated in UC patients, which may be related to the decrease of FA and VitB(12).

Involvement of cytochrome P450 3A4 and P-glycoprotein in first-pass intestinal extraction of omeprazole in rabbits.

AIM: To quantitatively evaluate in vivo first-pass intestinal extraction of omeprazole and to investigate the possible involvement of cytochrome P450 3A4 (CYP3A4) and P-glycoprotein (P-gp) in this process in rabbits. METHODS: Pharmacokinetic parameters were examined after intraduodenal (id), intraportal venous (ipv), and intravenous (iv) administration of omeprazole at various doses to intestinal and vascular access-ported rabbits. Extraction ratios in the liver and intestinal tract were determined from the area under the plasma concentration-time curve (AUC). In addition, omeprazole was administered by id or iv to rabbits alone or 30 min after the id administration of CYP3A4 or P-gp inhibitors (ketoconazole or verapamil, respectively). RESULTS: Pharmacokinetic parameters of omeprazole were dose-dependent after id, ipv, and iv administration at various doses. After id administration of 3 mg/kg omeprazole, the hepatic and intestinal extraction ratio was 57.18%+/-2.73% and 54.94%+/-1.85%, while the value was 59.29%+/-3.14% and 54.20%+/-1.53% after given 6 mg/kg, respectively. Compared with the control group, the presence of ketoconazole (60 mg/kg) or verapamil (9 mg/kg) significantly increased the area under the plasma concentration time curve (AUC) and the peak concentration (C(max)) of id-administered omeprazole, while it had no significant effect on omeprazole administered by iv. CONCLUSION: Oral omeprazole undergoes marked extraction in the small intestine, and increased bioavailability of the drug after id administration of ketoconazole and verapamil suggests that this increase results from inhibition of CYP3A4 and P-gp function in the intestine rather than the liver.