Development Of Metabolic Phenotype Research Articles

Метаболічний фенотип остеоартриту: подвійна роль ожиріння

Останніми роками спостерігається зростання інте-ресу до метаболічних змін при остеоартриті. В оглядовій статті підсумовані дані щодо метаболічного фенотипу остеоартриту, ролі ожиріння, дисліпідемії, цукрового діабету в розвитку метаболічного фенотипу. Поточні проспективні епідеміологічні дослідження демонструють наявність чітких асоціацій між остеоартритом і компонентами метаболічного синдрому. Деякі дослідники схильні розглядати метаболічний остеоартрит тільки як наслідок надлишкового навантаження на опорні суглоби внаслідок ожиріння. Однак численні недавні дослідження продемонстрували, що адипокіни і цитокіни, що продукуються жировою тканиною, гіперглікемія, інсулінорезистентність та дисліпідемія здатні порушувати метаболізм суглобових тканин. Вісцеральне ожиріння, дисліпідемія й інсулінорезистентність формують особливий вид запалення — низькорівневе, хронічне, пов’язане з метаболічними розладами, що отримало назву «метазапалення». Саме цей вид запалення відіграє вирішальну роль в патогенезі ожиріння, цукрового діабету 2-го типу та його ускладнень, а множинні сигнальні шляхи пов’язують інсулінорезистентність та імунну відповідь. Ожиріння здійснює двояку дію на перебіг остеоартриту: механічний вплив на опорні суглоби, а також генерація метазапалення, що порушує метаболізм суглобових тканин неопірних суглобів. Таким чином, ожиріння може впливати на патогенез і прогресування остеоартриту за допомогою біомеханічних ефектів, а також при збільшенні метастимулюючого запалення.

Epigenetic regulation of oxidative and inflammatory phenotypes in women with gestational diabetes and offspring

Abstract Background Hyperglycemia-induced oxidative stress and inflammation are potent drivers of atherosclerotic cardiovascular disease (ASCVD). Gestational diabetes (GDM) is characterized by chronic hyperglycemia during pregnancy and may represent a clinical model to study the mechanisms of oxidative stress and inflammation induced by hyperglycemia. GDM is associated with a range of adverse perinatal and long-term outcomes for both mother and offspring. In this perspective, it is emerging a putative association between maternal GDM and offspring's epigenetic trait. Purpose To investigate the link between histone modifications, oxidative stress and inflammatory phenotype as well as the transmission of epigenetic signatures to the offspring. Methods We analyzed peripheral blood mononuclear cells (PBMC) from GDM and control mothers as well as human umbilical vein endothelial cells (HUVEC) and cord blood mononuclear cells (CBMC) isolated from newborn umbilical cords obtained at delivery from both groups. Histone methyltransferase MLL1-dependent trimethylation of histone 3 at lysine 4 amino residue (H3K4me3) on NF-kB p65 subunit promoter region was assessed by chromatin immunoprecipitation (ChIP) and real-time qPCR in HUVEC, PBMC and CBMC, respectively. MLL1 and downstream inflammatory and redox genes were determined by real-time qPCR and immunocytochemistry in the presence and in the absence of MLL1 inhibitor MM-102. Measurement of reactive oxygen species (ROS) was performed by electron spin resonance spectroscopy. Results For the first time, we demonstrated a significant increase of MLL1 expression with subsequent MLL1-induced upregulation of NF-kB p65 gene via H3K4me3 in GDM as compared to control cells. MLL1-driven epigenetic remodeling of NF-kB p65 promoter is upstream to the activation of inflammatory pathway. Indeed, treatment with MM-102 decreased H3K4me3 and blunted expression of NF-kB p65 as well as VCAM-1, MCP-1 and IL-6 genes. We also found that expression of ROS scavenger aldehyde dehydrogenase 2 is reduced, whereas pro-oxidant nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit NOX4 is upregulated. Interestingly, the increased ROS generation observed in GDM is involved in the upregulation of MLL1 as shown by the restoring effect of antioxidant vitamin C on MLL1 expression levels. Conclusions Our results suggest that a complex interplay between oxidative stress and histone modifications are responsible for the GDM maternal inflammatory and oxidative phenotypes and its transmission to the offspring. The deciphering of epigenetic-induced chromatin remodelling opens the perspective for pharmacological reprogramming of adverse chromatin changes to reduce the burden of early development of metabolic phenotypes and ASCVD. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): University G. d'Annunzio MIUR fundings Schematic figure

Impact of Adaptive Thermogenesis in Mice on the Treatment of Obesity.

Obesity and associated metabolic diseases have become a priority area of study due to the exponential increase in their prevalence and the corresponding health and economic impact. In the last decade, brown adipose tissue has become an attractive target to treat obesity. However, environmental variables such as temperature and the dynamics of energy expenditure could influence brown adipose tissue activity. Currently, most metabolic studies are carried out at a room temperature of 21 °C, which is considered a thermoneutral zone for adult humans. However, in mice this chronic cold temperature triggers an increase in their adaptive thermogenesis. In this review, we aim to cover important aspects related to the adaptation of animals to room temperature, the influence of housing and temperature on the development of metabolic phenotypes in experimental mice and their translation to human physiology. Mice studies performed in chronic cold or thermoneutral conditions allow us to better understand underlying physiological mechanisms for successful, reproducible translation into humans in the fight against obesity and metabolic diseases.

Effects of temperature, dissolved oxygen, and substrate on the development of metabolic phenotypes in age-0 lake sturgeon (Acipenser fulvescens): implications for overwintering survival

The impact of early rearing environment on phenotypic development in teleosts has been reasonably well-documented, but only recently has attention been paid to sturgeon raised for conservation purposes. In the present study, we hypothesized that rearing environment will result in the development of distinct metabolic phenotypes in age-0 lake sturgeon (Acipenser fulvescens) and that these phenotypes will drive differential survival rates during a simulated overwintering event. Lake sturgeon gametes were fertilized and raised in one of three different environments: 16 °C + 100% dissolved oxygen (DO), 14 °C + 100% DO, and 16 °C + 80% DO, each with or without substrate. We measured standard metabolic rate, forced maximum metabolic rate, metabolic scope, energy density, hepatosomatic index, Fulton’s condition factor, and enzyme activities associated with ATP production. Our results suggest that subtle changes in abiotic environments during early life history result in the development of distinct metabolic phenotypes during the first year of life. These have important implications for survival of age-0 lake sturgeon when stocked in the fall of their first year.

Influence of a dynamic rearing environment on development of metabolic phenotypes in age-0 Lake Sturgeon, Acipenser fulvescens.

Environment–phenotype interactions are the most pronounced during early life stages and can strongly influence metabolism and ultimately ecological fitness. In the present study, we examined the effect of temperature [ambient river temperature (ART) vs ART+2°C], dissolved oxygen (DO; 100% vs 80%) and substrate (presence vs absence) on standard metabolic rate, forced maximum metabolic rate and metabolic scope with Fulton’s condition factor (K), energy density (ED) and critical thermal maximum (CTmax) in age-0 Lake Sturgeon, Acipenser fulvescens, before and after a simulated overwintering event. We found that all the environmental variables strongly influenced survival, K, ED and CTmax. Fish reared in elevated temperature showed higher mortality and reduced K pre-winter at 127 days post-hatch (dph). Interestingly, we did not find any significant difference in terms of metabolic rate between treatments at both sampling points of pre- and post-winter. Long-term exposure to 80% DO reduced ED in Lake Sturgeon post-winter at 272 dph. Our data suggest that substrate should be removed at the onset of exogenous feeding to enhance the survival rate of age-0 Lake Sturgeon in the first year of life. Effects of early rearing environment during larval development on survival over winter are discussed with respect to successful recruitment of stock enhanced Lake Sturgeon, a species that is at risk throughout its natural range.

Functional Roles of Proline/Arginine-Rich End Leucine-Rich Repeat Protein (PRELP) in Adipocytes

Adipose tissue fibrosis is recognized as a hallmark of adipose tissue dysfunction. We have previously identified PRELP as a novel regulator of adipogenesis by using lentiviral short hairpin RNA libraries targeting murine genomes. PRELP belongs to the family of leucine-rich repeat proteins, which are characterized by a series of adjacent leucine-rich motifs flanked by disulfide-bounded domains. Functionally, PRELP anchors basement membranes to connective tissues. However, roles of PRELP in adipocytes remain unclear. In the present study, we show that PRELP expression is up-regulated both in adipocytes of high-fat diet induced obesity mice and ob/ob mice. PRELP reduction in 3T3-L1 adipocytes leads to enhanced insulin signaling and insulin-stimulated glucose uptake. To determine functions of PRELP in the development of metabolic phenotypes, we generated adipocyte-specific PRELP transgenic mice. Adipose-specific overexpression of PRELP results in the development of significant adipose tissue fibrosis and insulin resistance on high fat diet without difference of body weight and adiposity. This phenotype is associated with increased expression of inflammation genes and decreased insulin signaling in adipose tissue of PRELP transgenic mice. Furthermore, we find that global Prelp deficient mice are protected from adipose tissue fibrosis and insulin resistance associated with high fat feeding. These data suggest that PRELP might play a key role in the development of adipose tissue remodeling in obesity. Disclosure J. Eguchi: None. J. Wada: None.

Abstract 1127: Natural-Killer T Cells are Involved in the Development of Glucose Intolerance and Microalbuminuria in Diet-Induced Obese Mice

Introduction: Natural killer T (NKT) cells are a unique subset of T lymphocytes, which recognize glycolipids and integrate inflammation producing pro-inflammatory cytokines on activation. We have demonstrated that NKT cells are present in atherosclerotic lesions and play a pivotal role in atherogenesis. NKT cells also reside in visceral adipose tissues, however, their pathogenic role has not been studied in metabolic derangements. Methods and Results: To determine whether NKT cells are involved in the development of metabolic phenotypes, male β 2 microglobulin knockout (KO) mice, which lack T cells and NKT cells, and C57BL/6J (WT) mice were fed an western diet (WD) containing 21% fat and 0.15% cholesterol or a chow diet for 13 weeks. In both KO (n=14) and WT (n=10) mice fed WD, visceral adipose-tissue weight, adipose cell size, and plasma leptin and non-HDL cholesterol levels were significantly increased compared to those fed a chow ( p< 0.05) but did not differ between KO and WT mice. However, in KO mice fed WD, impaired glucose tolerance (plasma glucose 15 minutes after intraperitoneal glucose injection, 228±7 vs 343±31 mg/dl, p< 0.001) and microalbuminuria (urine albumin/creatinin ratio, 10±1 vs 24±2 μg/mg, p< 0.0001) were significantly ameliorated, but not in WT mice. Plasma TNF-α was significantly lower in KO mice than in WT mice (29±6 vs 85±40 pg/ml, p< 0.05). Immunohistochemical staining of visceral adipose tissues revealed that F4/80 (+) macrophages in KO mice were markedly reduced to 34% of those in WT mice ( p< 0.0001). To further confirm that NKT cells can aggravate metabolic derangements, WT mice received α-galactosylceramide (0.1μg/g), which specifically activates NKT cells, (αgC, n=5) or saline (PBS, n=5) injection after 13 weeks of feeding WD. In αgC mice, impaired glucose tolerance (347±9 vs 308±13 mg/dl, p< 0.05) and microalbuminuria (35±8 vs 17±1 μg/mg, p< 0.05) were significantly exacerbated as compared to PBS mice. Conclusions: NKT cells enhance chronic inflammation in visceral adipose tissues and contribute to the development of metabolic derangements in diet-induced obese mice. NKT cells may be novel therapeutic targets in the prevention of metabolic syndrome.

C3H/HeJ mice carrying a toll-like receptor 4 mutation are protected against the development of insulin resistance in white adipose tissue in response to a high-fat diet

Inflammation is associated with obesity and has been implicated in the development of diabetes and atherosclerosis. During gram-negative bacterial infection, lipopolysaccharide causes an inflammatory reaction via toll-like receptor 4 (TLR4), which has an essential function in the induction of innate and adaptative immunity. Our aim was to determine what role TLR4 plays in the development of metabolic phenotypes during high-fat feeding. We evaluated metabolic consequences of a high-fat diet in TLR4 mutant mice (C3H/HeJ) and their respective controls. TLR4 inactivation reduced food intake without significant modification of body weight, but with higher epididymal adipose tissue mass and adipocyte hypertrophy. It also attenuated the inflammatory response and increased glucose transport and the expression levels of adiponectin and lipogenic markers in white adipose tissue. In addition, TLR4 inactivation blunted insulin resistance induced by lipopolysaccharide in differentiated adipocytes. Increased feeding efficiency in TLR4 mutant mice was associated with lower mass and lower expression of uncoupling protein 1 gene in brown adipose tissue. Finally, TLR4 inactivation slowed the development of hepatic steatosis, reducing the liver triacylglycerol content and also expression levels of lipogenic and fibrosis markers. TLR4 influences white adipose tissue inflammation and insulin sensitivity, as well as liver fat storage, and is important in the regulation of metabolic phenotype during a fat-enriched diet.

CCR2 modulates inflammatory and metabolic effects of high-fat feeding

The C-C motif chemokine receptor-2 (CCR2) regulates monocyte and macrophage recruitment and is necessary for macrophage-dependent inflammatory responses and the development of atherosclerosis. Although adipose tissue expression and circulating concentrations of CCL2 (also known as MCP1), a high-affinity ligand for CCR2, are elevated in obesity, the role of CCR2 in metabolic disorders, including insulin resistance, hepatic steatosis, and inflammation associated with obesity, has not been studied. To determine what role CCR2 plays in the development of metabolic phenotypes, we studied the effects of Ccr2 genotype on the development of obesity and its associated phenotypes. Genetic deficiency in Ccr2 reduced food intake and attenuated the development of obesity in mice fed a high-fat diet. In obese mice matched for adiposity, Ccr2 deficiency reduced macrophage content and the inflammatory profile of adipose tissue, increased adiponectin expression, ameliorated hepatic steatosis, and improved systemic glucose homeostasis and insulin sensitivity. In mice with established obesity, short-term treatment with a pharmacological antagonist of CCR2 lowered macrophage content of adipose tissue and improved insulin sensitivity without significantly altering body mass or improving hepatic steatosis. These data suggest that CCR2 influences the development of obesity and associated adipose tissue inflammation and systemic insulin resistance and plays a role in the maintenance of adipose tissue macrophages and insulin resistance once obesity and its metabolic consequences are established.

CCR2 modulates inflammatory and metabolic effects of high-fat feeding

The C-C motif chemokine receptor-2 (CCR2) regulates monocyte and macrophage recruitment and is necessary for macrophage-dependent inflammatory responses and the development of atherosclerosis. Although adipose tissue expression and circulating concentrations of CCL2 (also known as MCP1), a high-affinity ligand for CCR2, are elevated in obesity, the role of CCR2 in metabolic disorders, including insulin resistance, hepatic steatosis, and inflammation associated with obesity, has not been studied. To determine what role CCR2 plays in the development of metabolic phenotypes, we studied the effects of Ccr2 genotype on the development of obesity and its associated phenotypes. Genetic deficiency in Ccr2 reduced food intake and attenuated the development of obesity in mice fed a high-fat diet. In obese mice matched for adiposity, Ccr2 deficiency reduced macrophage content and the inflammatory profile of adipose tissue, increased adiponectin expression, ameliorated hepatic steatosis, and improved systemic glucose homeostasis and insulin sensitivity. In mice with established obesity, short-term treatment with a pharmacological antagonist of CCR2 lowered macrophage content of adipose tissue and improved insulin sensitivity without significantly altering body mass or improving hepatic steatosis. These data suggest that CCR2 influences the development of obesity and associated adipose tissue inflammation and systemic insulin resistance and plays a role in the maintenance of adipose tissue macrophages and insulin resistance once obesity and its metabolic consequences are established.