The mechanism of G protein-coupled receptor (GPCR) signal integration is controversial. While GPCR assembly into hetero-oligomers facilitates signal integration of different receptor types, cross-talk between Gai-and Gaqcoupled receptors is often thought to be oligomerization independent. In this study, we examined the mechanism of signal integration between the Gai-coupled type I cannabinoid receptor (CB 1 R) and the Gaq-coupled AT1R. We find that these two receptors functionally interact, resulting in the potentiation of AT1R signalling and coupling of AT1R to multiple G proteins. Importantly, using several methods, that is, co-immunoprecipitation and resonance energy transfer assays, as well as receptor-and heteromerselective antibodies, we show that AT1R and CB 1 R form receptor heteromers. We examined the physiological relevance of this interaction in hepatic stellate cells from ethanol-administered rats in which CB 1 R is upregulated. We found a significant upregulation of AT1R-CB 1 R heteromers and enhancement of angiotensin II-mediated signalling, as compared with cells from control animals. Moreover, blocking CB 1 R activity prevented angiotensin II-mediated mitogenic signalling and profibrogenic gene expression. These results provide a molecular basis for the pivotal role of heteromer-dependent signal integration in pathology.

Multiple peptide systems, including neuropeptide Y, leptin, ghrelin, and others, are involved with the control of food intake and body weight. The peptide LENSSPQAPARRLLPP (BigLEN) has been proposed to act through an unknown receptor to regulate body weight. In the present study, we used a combination of ligandbinding and receptor-activity assays to characterize a Gα i/o proteincoupled receptor activated by BigLEN in the mouse hypothalamus and Neuro2A cells. We then selected orphan G protein-coupled receptors expressed in the hypothalamus and Neuro2A cells and tested each for activation by BigLEN. G protein-coupled receptor 171 (GPR171) is activated by BigLEN, but not by the C terminally truncated peptide LittleLEN. The four C-terminal amino acids of BigLEN are sufficient to bind and activate GPR171. Overexpression of GPR171 leads to an increase, and knockdown leads to a decrease, in binding and signaling by BigLEN and the C-terminal peptide. In the hypothalamus GPR171 expression complements the expression of BigLEN, and its level and activity are elevated in mice lacking BigLEN. In mice, shRNA-mediated knockdown of hypothalamic GPR171 leads to a decrease in BigLEN signaling and results in changes in food intake and metabolism. The combination of GPR171 shRNA together with neutralization of BigLEN peptide by antibody absorption nearly eliminates acute feeding in food-deprived mice. Taken together, these results demonstrate that GPR171 is the BigLEN receptor and that the BigLEN-GPR171 system plays an important role in regulating responses associated with feeding and metabolism in mice.proSAAS | NPY/AgRP | neuroendocrine peptide | deorphanization | orexigenic

Interleukin (IL)-12 is a heterodimeric cytokine that is

The prenatal brain develops under the influence of an ever-changing hormonal milieu that includes endogenous fetal gonadal and adrenal hormones, placental and maternal hormones, and exogenous substances with hormonal activity that can cross the placental barrier. This review discusses the influences of endogenous fetal and maternal hormones on normal brain development and potential consequences of pathophysiological hormonal perturbations to the developing brain, with particular reference to autism. We also consider the effects of hormonal pharmaceuticals used for assisted reproduction, the maintenance of pregnancy, the prevention of congenital adrenal hypertrophy, and hormonal contraceptives continued into an unanticipated pregnancy, among others. These treatments, although in some instances life-saving, may have unintended consequences on the developing fetuses. Additional concern is raised by fetal exposures to endocrine-disrupting chemicals encountered universally by pregnant women from food/water containers, contaminated food, household chemicals, and other sources. What are the potential outcomes of prenatal steroid perturbations on neurodevelopmental and behavioral disorders, including autism-spectrum disorders? Our purposes here are 1) to summarize some consequences of steroid exposures during pregnancy for the development of brain and behavior in the offspring; 2) to summarize what is known about the relationships between exposures and behavior, including autism spectrum disorders; 3) to discuss the molecular underpinnings of such effects, especially molecular epigenetic mechanisms of prenatal steroid manipulations, a field that may explain effects of direct exposures, and even transgenerational effects; and 4) for all of these, to add cautionary notes about their interpretation in the name of scientific rigor.

Interleukin (IL)-12 is a heterodimeric cytokine produced by macrophages in response to intracellular pathogens and provides an obligatory signal for the differentiation of T-helper-1 cells. We previously reported an analysis of the IL-12 p40 promoter in RAW264.7 macrophages. Multiple control elements were involved in activation of transcription by bacterial products. A critical control element, located between ؊96 and ؊88, interacts with C/EBP family members. In this study, using a strategy to demonstrate functional activity in a minimal promoter context, three novel cis-acting elements are found to have an important role in IL-12 p40 promoter activation by lipopolysaccharide. One of these elements is characterized in detail. Mutations from ؊79 to ؊74 in the murine IL-12 p40 promoter significantly reduce lipopolysaccharide-induced promoter activity. Electrophoretic mobility shift assays demonstrate binding of AP-1 family members to this region. Spacing between the C/EBP and AP-1 site is important for promoter activation, suggesting cooperativity between these elements. c-Jun and a mutant c-Jun molecule activate the IL-12 p40 promoter and synergistically activate the promoter when co-expressed with C/EBP␤. Finally, this region of the promoter is demonstrated to be a target for mitogen-activated protein kinase and tolllike receptor signaling pathways.