Yuji Matsuya

Treatment with SRT1720, a SIRT1 activator, ameliorates fatty liver with reduced expression of lipogenic enzymes in MSG mice

Nonalcoholic fatty liver disease (NAFLD) is an abnormal liver metabolism often observed with insulin resistance and metabolic syndrome. Calorie restriction is a useful treatment for NAFLD and reportedly prolongs the life spans of several species in which sirtuin plays an important role. In this study, we examined whether the activation of SIRT1, a mammalian ortholog of sirtuin, may ameliorate the development of NAFLD. Monosodium glutamate (MSG) mice, which exhibited obesity and insulin resistance, were treated with SRT1720, a specific SIRT1 activator from the age of 6-16 wk. Sixteen-week-old MSG mice exhibited increased liver triglyceride content and elevated levels of aminotransferase. SRT1720 treatment significantly reduced these levels without affecting body weight or food intake. These results suggested that the administration of SRT1720 ameliorated the development of NAFLD in MSG mice. The expressions of lipogenic genes, such as sterol regulatory element-binding protein-1c, acetyl-CoA carboxylase, and fatty acid synthase, and the serum lipid profiles, including free fatty acids, were elevated in MSG mice and were reduced by SRT1720 treatment. SRT1720 treatment also reduced the expressions of lipogenic genes in cultured HepG2 cells. Furthermore, SRT1720 treatment decreased the expressions of marker genes for oxidative stress and inflammatory cytokines in the liver of MSG mice. Taken together, SRT1720 treatment may reduce liver lipid accumulation, at least in part, by directly reducing the expressions of lipogenic genes. The reduction of oxidative stress and inflammation may also be involved in the amelioration of NAFLD.

SRT1720, a SIRT1 activator, promotes tumor cell migration, and lung metastasis of breast cancer in mice

Silent information regulator 2 (SIR2) is a highly conserved protein, the mammalian orthologue of which, SIRT1, exhibits histone deacetylase activity. SIRT1 is involved not in only longevity due to caloric restriction but in a variety of diseases such as diabetes, cardiovascular dysfunction and neurodegeneration. However, accumulating evidence shows that SIRT1 is overexpressed in various types of malignant cells, and its inhibitors suppress the growth of tumor cells. The relationship between SIRT1 and metastasis remains to be clarified. Here, we examined the effect of SRT1720, a SIRT1 activator, on lung metastasis of breast cancer cells. 4T1 breast cancer cells were subcutaneously implanted into syngeneic BALB/c mice and SRT1720 was administered alone or with an antitumor agent, cisplatin. As expected, cisplatin decreased the lung metastasis score, whereas SRT1720 increased metastasis irrespective of cisplatin. In the primary tumors, cisplatin suppressed the mRNA level of angiopoietin-like protein 4 (angptl4), a lung metastasis-promoting gene product of breast cancer, but SRT1720 reduced the effectiveness of cisplatin. The results obtained with animal experiments were in accordance with those in human cancer cells; SRT1720 significantly increased the amount of VEGF secreted from MDA-MB-231 cells. Moreover, a transendothelial cell migration assay showed that SRT1720 promotes the migration of MDA-MB-231 cells across an endothelial cell layer despite the presence of cisplatin. These findings imply that SRT1720 promotes the pulmonary metastasis of breast cancer cells and SIRT1 may be an important target for suppressing metastasis to the lung.

Sirtuin 1 activator SRT1720 suppresses inflammation in an ovalbumin-induced mouse model of asthma.

Background and objective:  In asthma, reduced histone deacetylase activity and enhanced histone acetyltransferase activity in the lungs have been reported. However, the precise function of Sirtuin 1 (Sirt1), a class III histone deacetylase, and the effect of the Sirt1 activator SRT1720 on allergic inflammation have not been fully elucidated.

A novel compound, denosomin, ameliorates spinal cord injury via axonal growth associated with astrocyte-secreted vimentin

In the spinal cord injury (SCI) axon regeneration is inhibited by the glial scar, which contains reactive astrocytes that secrete inhibitory chondroitin sulphate proteoglycan (CSPG). We previously reported that a novel compound, denosomin, promotes axonal growth under degenerative conditions in cultured cortical neurons. In this study, we investigated the effects of denosomin on functional recovery in SCI mice and elucidated the mechanism though which denosomin induces axonal growth in the injured spinal cord.

Synthesis of sominone and its derivatives based on an RCM strategy: discovery of a novel anti-Alzheimer's disease medicine candidate "denosomin".

Synthesis of sominone was achieved starting from dehydroepiandrosterone on the basis of an RCM strategy for the construction of a delta-lactone side chain. This synthetic protocol was applied for the synthesis of several analogous derivatives including 1-deoxy-24-norsominone (denosomin), which was revealed to exhibit notable bioactivities for new antidementia chemotherapy, exceeding the original natural compound sominone.

Synthesis and antitumor evaluation of arctigenin derivatives based on antiausterity strategy.

A series of new (-)-arctigenin derivatives with variably modified O-alkyl groups were synthesized and their preferential cytotoxicity was evaluated against human pancreatic cancer cell line PANC-1 under nutrient-deprived conditions. The results showed that monoethoxy derivative 4i (PC(50), 0.49 μM), diethoxy derivative 4h (PC(50), 0.66 μM), and triethoxy derivative 4m (PC(50), 0.78 μM) showed the preferential cytotoxicities under nutrient-deprived conditions, which were identical to or more potent than (-)-arctigenin (1) (PC(50), 0.80 μM). Among them, we selected the triethoxy derivative 4m and examined its in vivo antitumor activity using a mouse xenograft model. Triethoxy derivative 4m exhibited also in vivo antitumor activity with the potency identical to or slightly more than (-)-arctigenin (1). These results would suggest that a modification of (-)-arctigenin structure could lead to a new drug based on the antiausterity strategy.

Reaction of amides with nitric oxide (NO)

Amides were allowed to react with nitric oxide in aprotic and non-ethereal solvents to give the corresponding N-nitroso derivatives. The reaction was accelerated by addition of oxygen. The solvent effect revealed that the reaction did not proceed in the presence of protic media.

Efficient Approach to 1,2-Diazepines via Formal Diazomethylene Insertion into the C–C bond of Cyclobutenones

Efficient monocyclic 1,2-diazepine formation via a tandem electrocyclization reaction of cyclobutenones with lithiodiazoacetate is demonstrated. The reaction proceeds through an oxy anion-accelerated 4π-ring opening of cyclobutene followed by an 8π-ring closure of the resultant oxy anion-substituted diazo-diene under mild conditions to furnish a 1,2-diazepine via formal diazomethylene insertion into the C-C bond of cyclobutenone.

Radical scavenging by N-aminoazaaromatics

N-Aminoazaaromatics were found to react with nitric oxide in the presence of oxygen to afford deaminated products in high yields. The reaction proceeded almost instantaneously in various solvents including water, and one to two equivalent of NO was consumed depending upon the amount of oxygen coexisted, and 1 equivalent of N2O was released in the reaction. In addition, N-aminoazoles were deaminated by potassium superoxide to give parent azoles in good yields. Two equivalents of superoxide was consumed, and about half equivalents of both nitrite and nitrate ion were released. The results demonstrated that N-aminoazoles have ability to protect the biological system against the oxidation promoted by radicals such as nitrogen oxides and superoxide.

Reductive deamination of aromatic amines with nitric oxide (NO)

Abstract Aromatic amines were treated with nitric oxide in tetrahydrofuran or chloroform under argon atmosphere to afford deaminated aromatic compounds in good yields. The reaction is suggested to proceed via aryl radicals, which are supposed to be formed by reduction of aryldiazonium salts with NO.