Immunosuppressive effects of DTCM-G, a novel inhibitor of the mTOR downstream signaling pathway

Anti-inflammatory effects of novel AP-1 and NF-κB inhibitors in dextran-sulfate-sodium-induced colitis in rats

The aim of the present study was to elucidate the anti-inflammatory effects of the two novel anti-inflammatory substances, 3-[(dodecylthiocarbonyl)-methyl]-glutarimide (DTCM-G) and dehydroxymethylepoxyquinomicin (DHMEQ), on DSS-induced colitis in rats. For this purpose, rats with dextran sulfate sodium (DSS)-induced colitis were randomly divided into 3 groups with 10 animals in each group as follows: i) the control group, which received 0.5 ml of 0.5% carboxymethyl cellulose (CMC; vehicle), ii) rats that received DTCM-G (20 mg/kg body weight in 0.5% CMC; the DTCM-G group), and iii) rats that received DHMEQ (15 mg/kg body weight in 0.5% CMC; the DHMEQ group). The animals were sacrificed after the 5-day treatment period, and tissue samples were taken from their colons and sectioned for histological evaluation. The tissue sections were stained with hematoxylin and eosin, and immunostained for leukocytes, lymphocytes, macrophages/monocytes and mast cells. The disease activity index (DAI), histological grading of colitis, and densities of several types of submucosal immune cells were compared between the controls, and the DTCM-G and DHMEQ groups. The DAI values were significantly lower in both the DTCM-G and DHMEQ groups than in the control group. The total scores for the histological grading of colitis were also significantly lower in the DTCM-G and DHMEQ groups than in the control group. The submucosal densities of leucocytes, lymphocytes, macrophages/monocytes and mast cells were significantly lower in the DTCM-G and DHMEQ groups than in the control group. Our findings indicate that the anti-inflammatory and anticancer effects of DTCM-G and DHMEQ, and the absence of any associated toxicity render them excellent therapeutic candidates for clinical use in the treatment of colitis.

Treatment with novel AP-1 and NF-κB inhibitors restores the colonic endocrine cells to normal levels in rats with DSS-induced colitis

The aim of this study was to determine the effects of two anti-inflammatory agents on the abnormalities in colonic endocrine cells in dextran sodium sulfate (DSS)-induced colitis. Colitis was induced in male Wistar rats (n=45) using DSS; a further 15 rats without colitis were included in a healthy control group. The animals with DSS-induced colitis were randomly divided into 3 treatment groups as follows: i) DSS group, rats were treated with 0.5 ml of 0.5% carboxymethyl cellulose (CMC); ii) DSS‑G group, rats were treated with 3-[(dodecylthiocarbonyl)‑methyl]‑glutarimide (DTCM‑G), a novel activator protein 1 (AP-1) inhibitor, 20 mg/kg in CMC; and iii) DSS‑Q group, rats were treated with dehydroxymethylepoxyquinomicin, a nuclear factor κB (NF-κB) inhibitor, 15 mg/kg in CMC. The treatments were administered intraperitoneally, twice daily for 5 days, after which the animals were sacrificed and tissue samples from the colon were immunostained for chromogranin A (CgA), serotonin, peptide YY (PYY), enteroglucagon, pancreatic polypeptide (PP), somatostatin, leukocytes, B/T lymphocytes, B lymphocytes, T lymphocytes, macrophages/monocytes and mast cells. The densities of these endocrine and immune cells were quantified by computer‑aided image analysis. The densities of CgA-, serotonin-, PYY- and enteroglucagon-producing cells were significantly higher, and those of PP- and somatostatin-producing cells were significantly lower in the DSS‑G, DSS‑Q and control groups than in the DSS group. The densities of all the immune cells were lower in the DSS‑G, DSS‑Q and control groups than in the DSS group. The densities of all endocrine cell types and immune cells in both the DSS groups treated with anti‑inflammatory agents were restored to control levels. In conclusion, our data demonstrate that there is an interaction between endocrine and immune cells during inflammation. This interaction with subsequent changes in endocrine cells is responsible for the clinical manifestation of colitis symptoms.

3-[(dodecylthiocarbonyl)methyl]-glutarimide attenuates graft arterial disease by suppressing alloimmune responses and vascular smooth muscle cell proliferation

BACKGROUND

Graft arterial disease (GAD) is a major cause of late graft loss after organ transplantation. Alloimmune responses and vascular remodeling eventually cause the transplant organ to develop GAD. In this study, we aimed to limit the development of GAD by inhibiting alloimmune responses and vascular smooth muscle cell (VSMC) proliferation with a new compound, 3-[(dodecylthiocarbonyl)methyl]-glutarimide ([DTCM]-glutarimide), in a murine cardiac model of GAD.

METHODS

The hearts from B6.CH-2 mice were transplanted into C57BL/6 mouse recipients to examine the extent of GAD. The recipients were treated with either vehicle or DTCM-glutarimide intraperitoneally (40 mg/kg per day) for 4 weeks.

RESULTS

The administration of DTCM-glutarimide attenuated GAD formation (luminal occlusion: 37.9 ± 5.9% vs 14.8 ± 5.4%, P < 0.05) by inhibiting the number of graft-infiltrating cells and decreasing alloreactive interferon (IFN)-γ production compared with control mice, as measured by the Enzyme-linked ImmunoSpot assay. In vitro, VSMCs proliferated on stimulation with either basic fibroblast growth factor or IFN-γ and splenocytes after transplantation, but the addition of DTCM-glutarimide resulted in the inhibition of VSMC proliferation. Moreover, DTCM-glutarimide suppressed cyclin D1 expression and inhibited cell cycle progression from G1 to S in VSMCs.

CONCLUSIONS

The compound DTCM-glutarimide suppressed GAD development by inhibiting not only alloimmune responses but also VSMC proliferation in the graft.

Activation of apoptosis by caspase-3-dependent specific RelB cleavage in anticancer agent-treated cancer cells: involvement of positive feedback mechanism

DTCM-glutarimide (DTCM-G) is a newly found anti-inflammatory agent. In the course of experiments with lymphoma cells, we found that DTCM-G induced specific RelB cleavage. Anticancer agent vinblastine also induced the specific RelB cleavage in human fibrosarcoma HT1080 cells. The site-directed mutagenesis analysis revealed that the Asp205 site in RelB was specifically cleaved possibly by caspase-3 in vinblastine-treated HT1080 cells. Moreover, the cells stably overexpressing RelB Asp205Ala were resistant to vinblastine-induced apoptosis. Thus, the specific Asp205 cleavage of RelB by caspase-3 would be involved in the apoptosis induction by anticancer agents, which would provide the positive feedback mechanism.

Amelioration of severe TNBS induced colitis by novel AP-1 and NF- κ B inhibitors in rats

AP-1 and NF-κB inhibitors, namely, DTCM-G and DHMEQ, were investigated in male Wistar rats with severe colitis, induced by TNBS. The animals were randomized into 3 groups. The control group received 0.5 mL of 0.5% of the vehicle i.p., the DTCM-G group received 22.5 mg/kg body weight DTCM-G in 0.5% i.p., and the DHMEQ group received 15 mg/kg body weight DHMEQ i.p., all twice daily for 5 days. The body weight losses and mortality rates were significantly higher in the control group than those in DTCM-G-treated and DHMEQ-treated groups. The endoscopic inflammation scores in the control, DTCM-G-treated, and DHMEQ-treated groups were 6.3 ± 0.7, 1.0 ± 0.3, and 0.7 ± 0.3, respectively (P = 0.004 and 0.02, resp.). The inflammation scores as assessed by the macroscopic appearance were 4.3 ± 0.8, 0.7 ± 0.3, and 1.2 ± 0.4 in the control, DTCM-G-treated, and DHMEQ-treated groups, respectively (P = 0.01 and 0.009, resp.). The histopathological inflammation scores were 6.4 ± 0.7, 2.0 ± 1.0, and 2.2 ± 0.6 in the control, DTCM-G-treated, and DHMEQ-treated groups, respectively (P = 0.03 and 0.01, resp.). It was concluded that DTCM-G and DHMEQ exhibit strong anti-inflammatory and anticancer activities with no apparent toxicity, which make them excellent drug candidates for clinical use in inflammatory bowel diseases.