Brown adipose tissue (BAT) is a primary site of energy expenditure through thermogenesis, which is mediated by the uncoupling protein-1 (UCP-1) in mitochondria. Here, we show that protein kinase G (PKG) is essential for brown fat cell differentiation. Induction of adipogenic markers and fat storage was impaired in the absence of PKGI. Furthermore, PKGI mediated the ability of nitric oxide (NO) and guanosine 3',5'-monophosphate (cGMP) to induce mitochondrial biogenesis and increase the abundance of UCP-1. Mechanistically, we found that PKGI controlled insulin signaling in BAT by inhibiting the activity of RhoA and Rho-associated kinase (ROCK), thereby relieving the inhibitory effects of ROCK on insulin receptor substrate-1 and activating the downstream phosphoinositide 3-kinase-Akt cascade. Thus, PKGI links NO and cGMP signaling with the RhoA-ROCK and the insulin pathways, thereby controlling induction of adipogenic and thermogenic programs during brown fat cell differentiation.

Morphine and the endogenous opioid peptide ␤-endorphin exert neuromodulatory as well as immunomodulatory effects, which are transduced by -opioid receptors. In this report we show that stimulation with interleukin-4 induces -opioid receptor transcripts in human primary blood cells (T cells and polymorphonuclear leukocytes), immune cell lines (Raji, U-937, and HMEC-1), and dendritic cells. In nonstimulated immune cells this gene is silent. In addition, receptor transcription is up-regulated by interleukin-4 in cultures of primary rat neurons. Transient transfection experiments in Raji and SH SY5Y neuronal cells with human and rat reporter gene constructs linked the interleukin-4 effect directly to cis-active receptor promoter elements located at nucleotide ؊997 on the human gene and nucleotide ؊727 on the rat gene. The interleukin-4 response elements function orientation independently. They bind STAT6 transcription factors as shown by electrophoretic mobility shift assays. In the human gene, a single nucleotide polymorphism within the interleukin-4 response element reduces the trans-activating potential of this element by 50%, which may affect the phenotype of persons carrying this variation. These findings provide a molecular basis for understanding bidirectional interactions between the opioid system and the immune system.Opioids are classically associated with phenomena such as analgesia, respiratory depression, and addiction. The effects of opioids are mediated by at least three different opioid receptors, termed , ␦, and , which belong to the G-protein-coupled membrane receptor family (1, 2). During the last years, evidence has accumulated showing that exogenous opiates like morphine and endogenous opioid peptides derived from the precursors proopiomelanocortin, proenkephalin, and prodynorphin have multiple immunomodulatory properties in addition to their classical functions as neuromodulators. It was stated that the endogenous opioid peptides would now be considered members of the cytokine family if they had been first discovered by immunologists (3). Elucidation of a broad bidirectional communication between the opioid system and the immune system strengthens this concept. Thus, morphine, the prototypical exogenous ligand for the receptor, is an immunosuppressive drug and is responsible for increased susceptibility of opioid addicts to infections (4 -8). Studies with -opioid receptor knockout mice emphasized the role of this receptor in immunosuppression (9). After chronic morphine treatment, these mice developed none of the symptoms characteristic of wild type mice, namely lymphoid organ atrophy, diminished CD4 ϩ / CD8 ϩ cell ratio and strongly reduced natural killer cell activity. In contrast, cytokines modulate the expression of opioid peptide genes and opioid receptor genes. For example, studies with IL-6 1 knockout mice revealed decreased levels of receptors in the brain compared with wild type animals, suggesting a positive regulation of this receptor by IL-6 in vivo (10). In vitro, up-regulation of ...

(Me-Ile-4)cyclosporin (SDZ NIM 811) is a 4-substituted cyclosporin which is devoid of immunosuppressive activity but retains full capacity for binding to cyclophilin and exhibits potent anti-human immunodeficiency virus type 1 (HIV-1) activity. SDZ NIM 811 selectively inhibits HIV-1 replication in T4 lymphocyte cell lines, in a monocytic cell line, and in HeLa T4 cells. Furthermore, its antiviral activity against laboratory strains and against clinical isolates from geographically distinct regions in primary T4 lymphocytes and in primary monocytes (50%o inhibitory concentration = 0.011 to 0.057 ,g/ml) was demonstrated. SDZ NIM 811 does not inhibit proviral gene expression or virus-specific enzyme functions, either free or bound to cyclophilin. The compound does not influence CD4 expression or inhibit fusion between virus-infected and uninfected cells. SDZ NIM 811 was, however, found to block formation of infectious particles from chronically infected cells. Oral administration to mice, rats, dogs, and monkeys resulted in levels in blood considerably exceeding the drug concentration, which completely blocked virus replication in primary cells. SDZ NIM 811 caused changes of toxicity parameters in rats to a smaller degree than cyclosporine (formerly cyclosporin A). Thus, the potent and selective anti-HIV-1 activity of SDZ NIM 811 and its favorable pharmacokinetic behavior together with its lower nephrotoxicity than that of cyclosporine make this compound a promising candidate for development as an anti-HIV drug.

With more than half a billion individuals affected worldwide, obesity has reached pandemic proportions. Development of "brown-like" or "brite" adipocytes within white adipose tissue (WAT) has potential antiobesity and insulin-sensitizing effects. We investigated the role of cyclic GMP (cGMP) signaling, focusing on cGMP-dependent protein kinase I (PKGI) in WAT. PKGI is expressed in murine WAT, primary adipocytes, and 3T3-L1. Treatment of adipocytes with cGMP resulted in increased adipogenesis, with a 54% increase in expression of peroxisome proliferator-activated receptor-γ. Lentiviral overexpression of PKGI further increased adipogenesis, whereas loss of PKGI significantly reduced adipogenic differentiation. In addition to adipogenic effects, PKGI had an antihypertrophic and anti-inflammatory effect via RhoA phosphorylation and reduction of proinflammatory adipokine expression. Moreover, PKGI induced a 4.3-fold increase in abundance of UCP-1 and the development of a brown-like thermogenic program in primary adipocytes. Notably, treatment of C57BL/6 mice with phosphodiesterase inhibitor sildenafil (12 mg/kg/d) for 7 d caused 4.6-fold increase in uncoupling protein-1 expression and promoted establishment of a brown fat cell-like phenotype ("browning") of WAT in vivo. Taken together, PKGI is a key regulator of cell size, adipokine secretion and browning of white fat depots and thus could be a valuable target in developing novel treatments for obesity.

Prodynorphin, the precursor of the dynorphin opioid peptides, has been shown to play an important role in several aspects of human diseases and complex traits, e.g., drug abuse, epilepsy, and mood disorders. The objective of this study was to identify polymorphisms in the 5Ј control region of the human prodynorphin gene and to relate these polymorphisms to prodynorphin gene expression. Within the core promoter region, a 68-bp sequence was found to occur as a polymorphic element, either singular or as tandemly repeated element two, three, or four times. This 68-bp repeat element contains an AP-1 transcription factor binding site as demonstrated by electrophoretic mobility shift assay. Reporter gene assays were performed and provided evidence for allele dependent different promoter activity. Dynorphin was found to be involved in many pathophysiological processes so that the described prodynorphin alleles may correlate with the occurrence of several diseases, for example, drug addiction. However, prodynorphin allelic distributions were not significantly different in heroin addicts and control subjects.