GPCR Compound Library

Thereby emerging as potential attractive targets for future therapeutic approaches. Work from our laboratory has recently identified a yet unrecognized pathway promoting inflammation in experimental steatohepatitis in mice. Using mice either deficient for the chemokine receptor CXCR6 or transgenic for a fluorescent protein in one of the CXCR6 alleles, the accumulation of natural killer T cells was identified as a rapid response to hepatocyte injury. Cxcr62/2 mice lacking type-I NKT cells were protected against acute- and chronic liver failure in two independent models of liver fibrosis, showed significantly attenuated hepatic inflammation and reduced levels of pro-inflammatory cytokines like tumor necrosis factor, monocyte chemoattractant protein-1 and interferon-c. The adoptive transfer of wildtype NKT cells into Cxcr6-deficient mice in a model of steatohepatitis restored inflammation and liver fibrosis. Our experimental data indicated that hepatic NKT cells specifically utilize its receptor CXCR6 for the rapid accumulation in injured livers, where they produce and release cytokines like interleukin 4 and IFNc that act on macrophages and possibly other hepatic cell compartments to initiate and perpetuate inflammation. We thus reasoned that inhibiting the cognate ligand for CXCR6, CXCL16, might hold therapeutic potential in steatohepatitis. Whereas in human inflamed livers CXCR6 is expressed by CD4 as well as CD8 T cells, NK cells and NKT cells the chemokine CXCL16 exists in a soluble and transmembrane form and is expressed by liver sinusoids, possibly allowing NKT cells to patrol hepatic vessels. CXCL16 is also expressed by hepatic macrophages, likely favoring interactions between NKT and Kupffer cells. Importantly, CXCL16 expression is up-regulated in acute or chronic liver injury in mice, but also in chronic liver diseases in humans. In this study, we investigated the pharmacological inhibition of CXCL16 using a monoclonal antibody as a novel therapeutic approach in experimental steatohepatitis in mice. Non-alcoholic fatty liver disease is a raising health burden in Western countries, which affect about 30% of the general adult population, is associated with an increased mortality and promote several medical complications like hepatocarcinogenesis in humans. Within the liver, hepatocyte apoptosis, ER stress and oxidative stress are key contributors to hepatocellular injury. Moreover, lipotoxic mediators and danger signals activate the hepatic macrophage pool, mainly Kupffer cells, which are critical for the initiation and perpetuation of the inflammatory response and release several inflammatory mediators. Such mediators, mainly cytokines and chemokines, attract inflammatory cells and activate parenchymal as well as non-parenchymal liver cells during NAFLD progression. In our study, we provide experimental Reversine evidence that interfering with the CXCR6-CXCL16 pathway might hold therapeutic potential in NAFLD. The administration of an anti-CXCL16 antibody blocked the rapid accumulation of patrolling hepatic NKT cells.

We studied the prevalence of high blood ASP1517 pressure in a longitudinal cohort study of children with NAFLD from pediatric centers across the United States. Children with NAFLD had a high rate of high blood pressure both at baseline and again at 48 weeks. The odds of having high blood pressure at baseline and high blood pressure that persisted at 48 weeks were associated with BMI, LDL-cholesterol and uric acid. Hepatic steatosis was associated with high blood pressure at baseline. The rates of high blood pressure in children with NAFLD exceeded what would be expected based upon the contribution of obesity alone. Population-based cohort studies estimate the prevalence of high blood pressure in obese, Although most children with NAFLD are overweight or obese, our finding that more than one of every three children with NAFLD had high blood pressure at baseline indicates that children with NAFLD are at particularly increased risk for high blood pressure. A previous single center study in overweight and obese children with biopsy-confirmed NAFLD demonstrated that mean systolic and diastolic blood pressure were significantly higher compared to overweight and obese controls without evidence of NAFLD. Similarly, studies in children have shown that hepatic steatosis, independent of degree of obesity, is associated with cardiac dysfunction., Notably, in our cohort, children with NAFLD who had high blood pressure at baseline had higher degrees of hepatic steatosis. Data are extremely limited on the persistence of high blood pressure in children. In our study, the prevalence of 21.4% for persistent high blood pressure over 48 weeks in children with NAFLD was much higher than reported for other groups of children with longitudinal data available. For example, in the National Heart, Lung, and Blood Institute Growth and Health Study, the rate of persistent high blood pressure over 18 months in girls was 0.6% overall and 3% in obese girls. NAFLD and high blood pressure share pathophysiologic factors such as systemic oxidative stress and vascular and adipose tissue inflammation, which can produce vascular endothelial dysfunction. In the setting of hepatic steatosis, liver endothelial dysfunction can occur even prior to development of hepatic inflammation and fibrosis. While it is not yet clear whether hypertension is a cause or consequence of endothelial dysfunction, exogenous infusion of endothelium-derived nitric oxide synthase inhibitors can produce hypertension in humans. Our finding that elevated serum levels of LDL-cholesterol and uric acid were associated with increased odds for both baseline and persistent high blood pressure in this cohort also supports a possible role for underlying endothelial dysfunction. High levels of LDL cholesterol have been shown to alter the activity of endothelial-derived nitric oxide synthase. Oxidized LDL is also associated with endothelial dysfunction and activation of the renin-angiotensin system., Likewise, elevated uric acid has been functionally linked to decreased endothelial nitric oxide synthase activity and nitric oxide production and in turn endothelial dysfunction.

The organ systems involved in energy homeostasis work in synergy to achieve the maintenance of whole body energy balance. As the largest metabolically active tissue in the body, skeletal muscle is a key determinant of resting energy expenditure and therefore plays a vital role in maintaining energy balance. Communication with other organs, including adipose tissue, is achieved through the secretion of molecular messengers into the circulation, termed myokines. Myostatin, a member of the transforming growth factor b family of secreted growth factors, is one such myokine. The initial studies showed that mice lacking the myostatin gene were kinase inhibitors extremely hypermuscular and had minimal body fat when compared to their wild-type counterparts. To date, myostatin has been widely characterised as a potent negative regulator of skeletal muscle mass and methods to inhibit myostatin function as a potential therapeutic treatment for increasing muscle mass in diseases such as muscular dystrophy and cancer cachexia have been explored. Myostatin is synthesised as an inactive precursor protein which subsequently undergoes two cleavages to produce the mature, active form of the protein. Mature myostatin is bound noncovalently to its propeptide and circulates in serum as an inactive complex. Active, mature myostatin binds selectively to the activin type II receptor kinase, ActRIIB. Studies in rodents and humans generally report that myostatin expression levels are highest in skeletal muscle, although it has also been identified in adipose tissue. Previous work from this laboratory supports these findings and extends them to the horse. These data confirmed that myostatin gene and precursor protein expression is greatest in skeletal muscles and that in the horse, although low levels of expression were detected in adipose tissue at the gene level, myostatin precursor protein was absent. Work in murine models and humans has identified that myostatin may have an important role in obesity development. Myostatin knock-out mice offered high-fat diets are resistant to gains in body fat, and although this effect may be secondary to the increases in lean body mass, myostatin had direct effects on adipocyte differentiation. Furthermore, blocking myostatin increased the functional capacity of brown adipose tissue and may even drive the browning of white adipose tissue through the up-regulation of BAT-specific genes. Myostatin gene expression was positively associated with obesity in both mouse and human studies, whilst blocking myostatin function in mature mice elicited positive effects on glucose and insulin dynamics. In comparison to human and rodent studies, there are fewer studies of myostatin in horses and ponies, and the extant reports generally focus on the identification of a number of single nucleotide polymorphisms in the myostatin gene. SNPs have been associated with different attributes including breeds of different morphological type, optimal race distance in Thoroughbred horses and skeletal muscle fibre type proportions in Quarter horses. To date, no work has been conducted to characterize the expression myostatin and its receptor against the setting of obesity in the horse or pony.

Multiple genera of fungi. In the first study to show inoculation of bats with Pd causes WNS, Lorch and colleagues noted that their captive study was not long enough to result in mortality despite histological evidence of infection among inoculated bats. Density-dependent growth of Pd may explain why mortality did not occur within the time period of their study, which inoculated bats with 500 000 conidia. Our mortality data are only suggestive of self-inhibition in Pd, however, and research documenting germination at varying concentrations of conidia is needed to directly address this hypothesis. Such research, along with studies documenting natural exposure dynamics among freeranging bats, are needed to better TWS119 inform captive studies of WNS, which typically inoculate bats with 500 000 conidia. Inoculations resulting in mortality patterns that differ from wild populations may produce misleading insights into WNS. It is notable that we were often unable to detect Pd DNA on swabs from bats inoculated with 500 conidia. This demonstrates that the number of Pd conidia did not exponentially increase on bats in this treatment. We hypothesize that bats have some ability to control the fungal infection at this level of exposure. Although the mechanism of control is uncertain, the increased frequency of periodic arousals observed in these treatments likely plays some role. Arousals provide opportunities for euthermic rest, grooming, and immune upregulation, although the brevity of periodic arousals in bats compared to other hibernating mammals likely limits potential immune responses to Pd. As previously discussed, however, the number of arousals bats can energetically sustain are limited, and the frequent arousals in bats inoculated with 500 conidia resulted in high mortality despite an ability to control the fungus. Furthermore, Pd always remained on some bats within the 500 conidia treatment groups, serving as vectors for continued Pd exposure within this hibernation chamber. Mortality in the remaining inoculation treatments was not significantly greater than controls in our model. This lack of difference was driven by the low mortality observed in the remaining inoculation treatments hibernated at 4uC and relatively high mortality in the 10uC control group. The mortalities in the 10uC control group are well explained by the logistic regression model. Mortalities in this group were primarily males with body condition indices at the onset of hibernation that were below the median body condition. It is well documented that lower temperatures are more energetically favorable for hibernating bats, a conclusion supported by our own data. Thus, it is not surprising that we observed high mortality among male bats, which aroused more frequently from hibernation, with low fat reserves when placed in an energetically unfavorable environment. Mortality among bats with low body condition in both control groups may also result from placing bats in environmental conditions that differ from their native hibernacula. The 4u and 10uC environmental chambers represented temperatures that are colder and warmer, respectively, than both of the hibernacula we sampled in Illinois and Michigan.

While some data support this hypothesis, the large variation observed in winter torpor behavior provides evidence that each sex exhibits diversity in their torpor behaviors. Furthermore, arousal from hibernation and energy savings while torpid are not only determined by sex. Frequency of arousals and torpid metabolic rates decrease with temperature, resulting in greater energy savings. Boyles and colleagues suggested that both sexes of little brown myotis select microclimates within caves for hibernation based upon their body condition, i.e. bats with less fat hibernating in colder regions to conserve energy. Thus, torpor patterns in free-ranging little brown myotis are influenced by the interaction of numerous variables, including sex, body condition, and environmental conditions. Because colder temperatures are conducive to greater energy savings for bats and are associated with slower fungal growth, we predicted that WNS mortality would be greater at higher temperatures. This was supported by our mortality and torpor duration results, the Ibrutinib latter of which found a significant interaction between Pd inoculation and temperature, and is consistent with population declines observed in little brown myotis hibernacula, where warmer hibernacula exhibited the largest declines. Similarly, we hypothesized fungal loads would be greater at 10uC, but contrary to our expectations, we did not detect differences in Pd loads between temperatures. Thus, Pd loads appear to be poor indicators of the severity of infection and WNS, as both mortality and frequency of arousals from hibernation increased at 10uC. It is important to note, however, that because 90% relative humidity was maintained in environmental chambers at both temperatures, the absolute humidity of the air was approximately 40% greater at 10uC. This difference in absolute humidity between temperatures could potentially result in different progressions of WNS, resulting in differences in the rates of evaporative water loss in bats or fungal invasion of the skin. Thus, the role of absolute humidity was unclear from our experiment. Regardless, the high variability in Pd loads detected at both temperatures highlights the variability in Pd growth on bats relative to growth patterns in culture. In free-ranging bats exposed to more variable initial Pd exposures than those used in our experiment, and inhabiting hibernacula with conditions that can fluctuate throughout the winter, change in fungal loads are likely to be even more variable. In addition to being more variable, exposure to Pd in free-ranging bats is likely to occur repeatedly during the winter, as bats move about within and among hibernacula. These dynamics of Pd spread are poorly understood, however, and more research in this area is needed. Also contrary to our prediction, we observed the greatest mortality and shortest torpor bouts in bats inoculated with the least concentrated solution of Pd conidia. This paradoxical result could be explained if lower concentrations of Pd grow differently than Pd at high densities. We hypothesize that Pd germination is inversely related to the density of conidia, resulting in more rapid fungal invasion and mortality in bats inoculated with 500 conidia.