Adipokines oversecreted by omental adipose tissue in human obesity

Central-omental obesity plays a causative role in the pathogenesis of the metabolic syndrome. Adipokines are involved in the pathogenesis of this syndrome. However, adipokines secreted by omental adipose tissue (OAT) are still poorly characterized in human obesity. Therefore, we searched for novel adipokines abnormally secreted by OAT in obesity and examined their relationships with some features of metabolic syndrome and the respective contribution of adipocytes vs. stromal-vascular cells. OAT from obese and nonobese men was fractionated into adipocytes and SV cells, which were then cultured. Medium was screened by medium-scale protein arrays and ELISAs. Adipokine mRNA levels were measured by real-time RT-qPCR. We detected 16 cytokines secreted by each cellular fraction of lean and obese subjects. Of the 16 cytokines, six adipokines were newly identified as secretory products of OAT, which were dysregulated in obesity: three chemokines (growth-related oncogen factor, RANTES, macrophage inflammatory protein-1beta), one interleukin (IL-7), one tissue inhibitor of metalloproteinases (TIMP-1), and one growth factor (thrombopoietin). Their secretion and expression were enhanced in obesity, with a relatively similar contribution of the two fractions. The higher proportion of macrophages and endothelial cells in obesity may contribute to this enhanced production as well as changes in intrinsic properties of hypertrophied adipocytes. Accordingly, mRNA concentrations of most of these adipokines increased during adipocyte differentiation. Eventually, expression of the investigated adipokines did correlate with several features of the metabolic syndrome. In conclusion, six adipokines were newly identified as oversecreted by OAT in obesity. These adipokines may link obesity to its cardiovascular or metabolic comorbidities.     

Giant reticulospinal synapse in lamprey: molecular links between active and periactive zones

Deciphering the function of synaptic release sites is central to understanding neuronal communication. Here, we review studies of the lamprey giant reticulospinal synapse, a model that can be used to dissect synaptic vesicle trafficking at single release sites. The presynaptic axon is large and contains active zones that are spatially separated from each other. During activity, synaptic vesicle membrane is shuttled between the active zone and the periactive zone at which endocytosis occurs. Recent studies have shown that the periactive zone contains an actin-rich cytomatrix that expands during synaptic activity. This cytomatrix has been implicated in multiple functions that include (1) activity-dependent trafficking of proteins between the synaptic vesicle cluster and the periactive zone, (2) synaptic vesicle endocytosis, and (3) the movement of newly formed synaptic vesicles to the vesicle cluster. The actin cytomatrix thus provides a link between the active zone and the periactive zone; this link appears to be critical for sustained cycling of synaptic vesicles.This work was supported by Swedish Research Council grants (K2004-33X-11287-10A, LB; K2005-32X-13473-06A, OS).     

The mahogany mouse mutation: further links between pigmentation, obesity and the immune system.

Completely different lines of experimentation have identified attractin, a protein that seems to have multiple roles in regulating physiological processes. It affects the balance between agonist and antagonist at receptors on melanocytes, modifies behaviour and basal metabolic rate, and mediates an interaction between activated T cells and macrophages. It may well be a target for development of drugs to treat obesity.     

Charting the molecular links between driver and susceptibility genes in colorectal cancer

Despite significant advances in the identification of specific genes and pathways important in the onset and progression of colorectal cancer (CRC), mechanistic insight into the relationship between driver and susceptibility genes is needed. In this paper, we systematically explore physical interactions between causative and putative CRC susceptibility genes to reveal the molecular mechanisms involved in tumor biology. In total, we identify 622 high-confidence protein–protein interactions between 42 CRC causative and 65 candidate susceptibility genes. Among the latter, 28 are located in the CRCS9 loci, related to the etiology of CRC, and 17 are co-expressed with well-established CRC drivers, which makes them excellent candidates for further functional studies. Moreover, we find a high degree of functional coherence between connected driver and susceptibility genes, which indicates that our network-based strategy is useful to gain insight into the underlying mechanisms of those proteins with unknown roles in CRC.     

The peptide molecular links between the central nervous and the immune systems

Summary. The central nervous system (CNS) and the immune system were for many years considered as two autonomous systems. Now, the reciprocal connections between them are generally recognized and very well documented. The links are realized mainly by various immuno- and neuropeptides. In the review the influence of the following immunopeptides on CNS is presented: tuftsin, thymulin, thymopoietin and thymopentin, thymosins, and thymic humoral factor. On the other side, the activity in the immune system of such neuropeptides as substance P, neurotensin, some neurokinins, enkephalins, and endorphins is discussed.     

连接肥胖和糖尿病的激素——抵抗素

2型糖尿病的发生主要是因为组织对胰岛素抵抗的缘故,往往与肥胖症相伴随,肥胖引起胰岛素抵抗的确切机制尚不清楚。抵抗素（resistin)是新近发现的一种由脂肪细胞分泌的激素,其作用是对抗胰岛素,使血糖水平升高,脂肪细胞增生繁殖而致肥胖,是糖尿病和肥胖症研究领域的突破性进展。抵抗素的发现对于糖尿病的治疗具有重要的指导意义。     

Adipokines underlie the early origins of obesity and associated metabolic comorbidities in the offspring of women with pregestational obesity

Maternal pregestational obesity is a well-known risk factor for offspring obesity, metabolic syndrome, cardiovascular disease and type 2 diabetes. The mechanisms by which maternal obesity can induce alterations in fetal and later neonatal metabolism are not fully elucidated due to its complexity and multifactorial causes. Two adipokines, leptin and adiponectin, are involved in fetal and postnatal growth trajectories, and both are altered in women with pregestational obesity. The placenta synthesizes leptin, which goes mainly to the maternal circulation and in lesser amount to the developing fetus. Maternal pregestational obesity and hyperleptinemia are associated with placental dysfunction and changes in nutrient transporters which directly affect fetal growth and development. By the other side, the embryo can produce its own leptin from early in development, which is associated to fetal weight and adiposity. Adiponectin, an insulin-sensitizing adipokine, is downregulated in maternal obesity. High molecular weight (HMW) adiponectin is the most abundant form and with most biological actions. In maternal obesity lower total and HMW adiponectin levels have been described in the mother, paralleled with high levels in the umbilical cord. Several studies have found that cord blood adiponectin levels are related with postnatal growth trajectories, and it has been suggested that low adiponectin levels in women with pregestational obesity enhance placental insulin sensitivity and activation of placental amino acid transport systems, supporting fetal overgrowth. The possible mechanisms by which maternal pregestational obesity, focusing in the actions of leptin and adiponectin, affects the fetal development and postnatal growth trajectories in their offspring are discussed.     

Deciphering the molecular and physiological connections between obesity and breast cancer

Obesity is associated with the higher risk of breast cancer in postmenopausal women. The leptin signaling pathway is recognized to primarily regulate energy balance and associated with breast cancer. Furthermore, the estrogen signaling pathway plays a critical role in breast carcinogenesis. In this review, we discuss how obesity is linked to breast cancer via cross-talk of leptin and estrogen pathways.     

Molecular links between endometriosis and cancer

Endometriosis is the leading cause of morbidity among premenopausal women affecting about 1 in 10 females. The features shared by endometriosis and cancer include the ability to evade apoptosis, the stem cell-like ability and angiogenic potential. As such characteristics are encoded by the cell's genetic constitution, acquired mutations are responsible for the malignant transformation of endometriosis. Indeed, a number of tumour-suppressor genes and proto-oncogenes, such as protein 53 (P53) and B-cell lymphoma 2 (BCL-2) respectively, are mutated and as a result differentially expressed between endometriotic and malignant tissue associated with endometriosis. Moreover, cytokines and macrophages, both of which are inflammatory mediators have been implicated in the transformation process. The angiogenic properties possessed by cancer arising from endometriosis signifies a bad prognosis, while the stem cell-like activity possessed by both endometriosis and cancer has been attributed to the effect of oestrogen. A number of differences between endometriosis and cancer are found at the molecular level. Considering the link between these two pathologies, the three components which fuel the malignant transformation of endometriosis can be embodied in the endometriosis-induced carcinoma (EIC) triangle which shows the intricate relationship between endocrinologic, immunologic and genetic components.     

Molecular links between centrosome and midbody

The terminal step in cytokinesis that severs a cell in two-abscission-is poorly understood. In Developmental Cell, Fabbro et al (2005) identify a centrosome protein whose multiple phosphorylations regulate its movement from centrosome to midbody and completion of abscission.