Functional role of ADAMTS5 in adiposity and metabolic health.

Previous studies with gene-deficient mice (ADAMTS5-P) revealed that ADAMTS5 (A Disintegrin And Metalloproteinase with Thrombospondin type 1 motifs, member 5) plays a functional role in adiposity and metabolic health. To confirm these observations, we have performed similar studies with an independently generated strain of ADAMTS5 deficient mice (ADAMTS5-J). Upon cold exposure as well as after high-fat diet feeding (diet-induced obesity or DIO model), these knockout (KO) mice developed less subcutaneous and gonadal white adipose tissue (WAT) as compared to their wild-type (WT) littermates (reduction was more pronounced in ADAMTS5-P mice).

Antioxidant Treatment Improves Cardiac Dysfunction in a Murine Model of Premature Aging.

Bmal1-(brain and muscle ARNT-like protein-1) deficient (Bmal1) mice prematurely age because of an increased reactive oxygen species (ROS) production. These mice also show a decline in cardiac function with age. We investigated whether an antioxidant treatment can ameliorate the declining cardiac function in prematurely aged Bmal1 mice.

CD36 deficiency blunts effects of diet on regulatory T cells in murine gonadal adipose tissue and mesenteric lymph nodes.

The effect of cluster of differentiation (CD)36 on regulatory T cells (Treg) was investigated in gonadal (GN) adipose tissues and mesenteric lymph nodes (MLN) of wild-type (WT) and CD36 deficient (CD36(-/-)) mice kept on standard fat (SFD, lean) or on high fat diet (HFD, obese). GN adipose tissue mass was smaller, but MLN size larger for obese CD36(-/-) versus obese WT mice. Overall, the reduction of Treg cells in GN adipose tissue and MLN after a HFD is much more prominent in WT than CD36(-/-) mice.

ADAMTS13 deficiency in mice does not affect adipose tissue development.

Background: BMI and ADAMTS13 levels are positively correlated in man. Development of obesity is associated with angiogenesis and inflammation, and increased ADAMTS13 synthesis in the liver.

Methods: Male wild-type (WT) and ADAMTS13 deficient (Adamts13-/-) mice were kept on normal chow (SFD) or high fat diet (HFD) for 15 weeks.

Gelatinase B (MMP-9) gene silencing does not affect murine preadipocyte differentiation.

Growth of adipose tissue involves differentiation of preadipocytes into mature lipid-containing adipocytes. The matrix metalloproteinases (MMPs) are known regulators of adipose tissue biology, and previous studies suggested a key role for gelatinase B (MMP-9) in adipogenesis. In the present study we have evaluated a potential functional role of MMP-9 by performing gene silencing in 3T3-F442A preadipocytes.

FGF receptor antagonism does not affect adipose tissue development in nutritionally induced obesity.

The fibroblast growth factor (FGF)-FGF receptor (FGFR) system plays a role in angiogenesis and maintenance of vascular integrity, but its potential role in adipose tissue related angiogenesis and development is still unknown. Administration of SSR, a low molecular weight inhibitor of multiple FGFRs, did not significantly affect body weight nor weight of subcutaneous or gonadal (GON) fat, as compared with pair-fed control mice. Adipocyte hypertrophy and reduced adipocyte density were only observed in GON adipose tissues of treated mice.

Effect of rosiglitazone on liver structure and function in genetically diabetic Akita mice.

Genetically diabetic Akita mice, kept on a high-fat and high-cholesterol diet, and treated with the peroxisome proliferator-activated receptor-γ agonist rosiglitazone (10 mg/kg per day during 4 months), displayed rosiglitazone-induced side effects, similar to those observed in patients, including weight and fat gain and early signs of hypertrophic cardiomyopathy. As several cases of hepatotoxicity were reported in patients receiving rosiglitazone treatment, this study evaluated whether rosiglitazone also induced hepatotoxicity in these diabetic animals. Liver structure and function was analysed in wild-type and rosiglitazone-treated and untreated Akita mice, kept for 4 months on the high-fat and high-cholesterol diet.

Mice deficient in the respiratory chain gene Cox6a2 are protected against high-fat diet-induced obesity and insulin resistance.

Oxidative phosphorylation in mitochondria is responsible for 90% of ATP synthesis in most cells. This essential housekeeping function is mediated by nuclear and mitochondrial genes encoding subunits of complex I to V of the respiratory chain. Although complex IV is the best studied of these complexes, the exact function of the striated muscle-specific subunit COX6A2 is still poorly understood.

Effect of weight loss on gelatinase levels in obese mice.

1. Gelatinases (matrix metalloproteinase (MMP)-2 and MMP-9) might play a role in the development and structural organization of adipose tissue. Obese mice were subjected to caloric restriction (from 82 to 27 kJ/day) for 6 weeks, in order to investigate the effect of drastic weight loss on gelatinase mRNA, protein and activity levels.

Plasminogen activator inhibitor-1 impairs plasminogen activation-mediated vascular smooth muscle cell apoptosis.

The role of plasminogen activator inhibitor-1 (PAI-1) in vascular smooth muscle cell (VSMC) apoptosis mediated by plasminogen activation was studied with the use of aorticVSMC derived from mice with deficiency of PAI-1 (PAI-1 (-/-) ), tissue-type (t-PA (-/-) ) or urokinase-type (u-PA (-/-) ) plasminogen activator or from wildtype (WT) mice with corresponding genetic background. Plasminogen incubated with confluent VSMC was activated in a concentration-dependent and saturable manner for all four cell types, with maximal activation rates that were comparable for WT, u-PA (-/-) and t-PA (-/-) cells, but about two-fold higher for PAI-1 (-/-) cells. Plasminogen activation was impaired by addition of the lysine analogue 6-aminohexanoic acid, and by addition of t-PA and u-PA neutralizing antibodies, suggesting that it depends on binding to cell surface COOH-terminal lysine residues, and on plasminogen activator activity.

Generation of a stable activated thrombin activable fibrinolysis inhibitor variant.

Activated thrombin activable fibrinolysis inhibitor (TAFIa), generated upon activation of TAFI, exerts an antifibrinolytic effect. TAFIa is a thermolabile enzyme, inactivated through a conformational change. The objective of the current study was to generate a stable variant of human TAFIa.