Sirtuin 1 suppresses nuclear factor κB induced transactivation and pro-inflammatory cytokine expression in cat fibroblast cells

Pleiotropic Effects of Resveratrol on Aging-Related Cardiovascular Diseases-What Can We Learn from Research in Dogs?

Resveratrol (RES) is a polyphenol with natural anti-inflammatory and antioxidant properties. It is found in abundance in plants, i.e., grapes and mulberry fruit. In addition, synthetic forms of RES exist. Since the discovery of its specific biological properties, RES has emerged as a candidate substance not only with modeling effects on the immune response but also as an important factor in preventing the onset and progression of cardiovascular disease (CVD). Previous research provided strong evidence of the effects of RES on platelets, mitochondria, cardiomyocytes, and vascular endothelial function. In addition, RES positively affects the coagulation system and vasodilatory function and improves blood flow. Not only in humans but also in veterinary medicine, cardiovascular diseases have one of the highest incidence rates. Canine and human species co-evolved and share recent evolutionary selection processes, and interestingly, numerous pathologies of companion dogs have a human counterpart. Knowledge of the impact of RES on the cardiovascular system of dogs is becoming clearer in the literature. Dogs have long been recognized as valuable animal models for the study of various human diseases as they share many physiological and genetic similarities with humans. In this review, we aim to shed light on the pleiotropic effects of resveratrol on cardiovascular health in dogs as a translational model for human cardiovascular diseases.

Shiitake mushroom powder supplementation increase antioxidative activity in dogs

Introduction

The prevalence of age-related diseases, including obesity (a lipid metabolism disorder), increases with the increase in a dog's lifespan. Most of age-related diseases are associated with oxidative stress by excessive production of reactive oxygen species (ROS) from impaired mitochondrial functions. Safe and effective supplements with antioxidative and anti-inflammatory activities are required to prevent obesity and associated complications. Shiitake mushroom exhibit various functions including antioxidant activity. We investigated the effect of shiitake powder supplementation in healthy dogs.

Methods

Shiitake powder was supplemented at a dose of 800 mg/kg body weight/day for 4 weeks. The dose was set as 0.60-0.65 mg/kg/day of eritadenine, a hypocholesterolemic factor.

Results

The body weight and body condition score of the dogs did not change after shiitake supplementation. In contrast, plasma total cholesterol concentrations decreased and superoxide dismutase activity and leukocyte sirtuin1 mRNA expression increased significantly in the dogs that received the supplement.

Discussion

Oral administration of shiitake powder increased antioxidative activity. The supplement may be useful in ameliorating the signs of age-related diseases, including obesity, in dogs.

Presence of the apolipoprotein E-ε4 allele is associated with an increased risk of sepsis progression

Growing evidence indicated that single nucleotide polymorphisms (SNPs) in the apolipoprotein E (APOE) gene are related to increase the risk of many inflammatory-related diseases. However, few genetic studies have associated the APOE gene polymorphism with sepsis. This study was to investigate the clinical relevance of the APOE gene polymorphism in the onset and progression of sepsis. A multicenter case–control association study with a large sample size (601 septic patients and 699 healthy individuals) was conducted. Clinical data showed that the APOEε4 allele was overrepresented among all patients with septic shock (p = 0.031) compared with sepsis subtype, suggesting that APOEε4 allele may associated with increased susceptibility to the progression of sepsis. Moreover, the APOE mRNA levels decreased after lipopolysaccharide (LPS) stimulation in cells in culture. Then 21 healthy individuals to extract PBMC for genotype grouping (APOE4+ group 8; APOE4− group 13) was selected to evaluate the effect on APOE level, and results showed that the expression level of APOE in APOE4+ group and APOE4− group did not differ in mRNA levels after an LPS challenge, but the protein levels in APOE4+ group decreased slower than that in APOE4− group, and this process was accompanied by the upregulation of proinflammatory cytokines. These results provide evidence that the APOEε4 allele might be associated with the development of sepsis and a potential risk factor that can be used in the prognosis of sepsis.

Liraglutide exerts an anti-inflammatory action in obese patients with type 2 diabetes

INTRODUCTION

Liraglutide (L) is the analogue of human glucagon-like peptide 1 which stimulates glucose-dependent insulin secretion and can modify the level of inflammatory biomarkers. L can influence NF-kB inflammatory cascade, but the mechanisms of anti-inflammatory activities of L remain to be determined. In animal models L influenced an activity of Sirtuin 1(SIRT1). Moreover, recent evidences strongly suggest that SIRT1 up-regulation may serve as a potent therapeutic approach against development and progression of diabetic complications. The aim of this study was to investigate L effects directed on the pro-inflammatory NF-kB pathway and expression of SIRT1 in obese patients with type 2 diabetes mellitus (DM).

MATERIALS AND METHODS

15 obese patients with type 2 diabetes were studied, all using metformin (1-2 g/day) and sulfonylurea (glimiperide). All patients received L 1.2 mg daily add-on to stable therapy for 6 weeks. Blood samples were collected before, 6 weeks after start of treatment and after an overnight fast 6 weeks after stopping L, mononuclear cells (MNC) were isolated. The mRNA expressions of TNF-α, TLR2, TLR4, NOD1, IL-2 and SIRT1 were measured in MNC by RT-PCR. Ceruloplasmin concentration was measured in plasma by photometric method.

RESULTS

In this add-on pilot clinical investigation we received new data that L can inhibit proinflammatory NF-kB pathway by increased SIRT1 expression in obese patients with type 2 DM improving metabolic profile. The mRNA expression in MNC of TNF-α, IkB, TLR2, TLR4, and plasma ceruloplasmin fell after 6 weeks of L. Expressions of IL-2 and NOD-1 were stable. There was a significant increase of SIRT1 mRNA expression. The mRNA expression in MNC of TNF-α, IkB, TLR2, TLR4, NOD1, SIRT1 and ceruloplasmin concentrations did not reverse to baseline levels after 6 weeks stopping of L treatment. IL-2 expression decreased in comparison with basic level.

CONCLUSIONS

L has a potent anti-inflammatory effect as do GLP-1 agonists due to inhibition of NF-kB pathways and up-regulate SIRT1 expression, down-regulating pro-inflammatory factors including cytokines (TNF-α), extra- and intracellular receptors (TLR2, TLR4), and inflammation markers such as ceruloplasmin. Long lasting effects of L can be mediated by epigenetic regulation of NF-kB pathway by SIRT-1.

Detection of Sirtuin-1 protein expression in peripheral blood leukocytes in dogs

Sirtuin-1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD⁺)-dependent histone deacetylase with a large number of protein substrates. It has attracted a lot of attention in association with extending lifespan. The objective of this study was to enable the evaluation of SIRT1 expression in peripheral blood mononuclear cells (PBMCs) from dogs by flow cytometry. Three transcript variants were amplified from PBMCs by reverse transcription PCR and the nucleotide sequences were analyzed. On the basis of deduced amino acid sequence, a monoclonal antibody against human SIRT1, 1F3, was selected to detect canine SIRT1. Canine SIRT1 in peripheral blood mononuclear cells was successfully detected by western blotting using this antibody. Intracellular canine SIRT1 was also detected in permeabilized 293T cells transfected with a canine SIRT1 expression plasmid by flow cytometry using this antibody. SIRT1 was detected in all leukocyte subsets including lymphocytes, granulocytes and monocytes. The expression level was markedly different among individual dogs. These results indicated that the method applied in this study is useful for evaluating canine SIRT1 levels in PBMCs from dogs.