(+)‐Z‐Bisdehydrodoisynolic Acid Ameliorates Obesity and the Metabolic Syndrome in Female ZDF Rats

Objective: The putative selective estrogen receptor modulator (+)‐Z‐bisdehydrodoisynolic acid (Z‐BDDA) has been found to improve cardiovascular risk in rodents. The objective of this study was to investigate the effectiveness of (+)‐Z‐BDDA compared with the antidiabetic drug, rosiglitazone, in treating obesity and risk factors associated with the metabolic syndrome. Research Methods and Procedures: Female Zucker Diabetic Fatty rats were randomly assigned to three treatment groups for 29 weeks: control (C), 1.8 mg (+)‐Z‐BDDA/kg diet [control diet + (+)‐Z‐BDDA (CB)], or 100 mg rosiglitazone/kg diet [control diet + rosiglitazone (CR)]. At sacrifice, physiological, biochemical, and molecular parameters were examined. Results: CB animals gained less weight and exhibited a decrease in total body lipids (p < 0.05) as compared with C or CR rats. Body weight and total body lipids were the highest in CR rats (p < 0.05). Liver weights in CB and CR rats were lower (p < 0.05) than in C rats, whereas kidney weights were lower in CB (p < 0.05) than in C and CR animals. Fasting plasma glucose was lower (p < 0.05) in the CB and CR animals when compared with C animals. C rats exhibited the highest concentration of total plasma cholesterol, and CR‐treated rats exhibited the lowest concentration. Plasma triglycerides followed the same pattern as plasma cholesterol. Histomorphometry of heart vasculature revealed that CB and CR treatments produced a significant shift from small to large venules and arterioles compared with C (p < 0.05). Liver expression profiles of peroxisome proliferator‐activated receptor (PPAR) α, PPARγ, and PPAR‐regulated genes revealed encouraging CB‐induced effects. Discussion: These results suggest that (+)‐Z‐BDDA may have applications in treating obesity and complications associated with the metabolic syndrome.     

Do gut symbiotes reflect the endemism of their host black flies (Diptera: Simuliidae) in the Caucasus of Armenia?

Aim We tested the hypothesis that endemism of black flies in the Caucasus of Armenia is reflected in their gut symbiotes, i.e. trichomycete fungi and ichthyosporean protists. Location The study area, Armenia, is a biodiversity hotspot, with high levels of plant and animal endemism. Located in the southern Caucasus, Armenia is a rugged, mountainous, landlocked country of 29,800 km², with fast‐flowing rivers and little forested land. About half of the 51 species of black flies in Armenia are endemic to the Caucasus. Methods The larvae of 22 species of black flies, including seven endemic to the Caucasus, were collected from 35 sites throughout Armenia, from 1998 to 2004, and assayed microscopically for gut‐inhabiting trichomycete fungi and ichthyosporean protists. Results Nearly 68% of larval black flies in Armenia contained at least one species of gut symbiote, with a mean of 0.9 ± 0.04 species per host larva. Eight species of trichomycete fungi and two species of ichthyosporeans were found in larval guts. Seven of these species were recorded for the first time in Asian black flies. Species accumulation curves showed no additional species of gut symbiotes after 17 host species and 22 sites had been examined. All gut symbiotes were widely distributed, indicating an absence of endemic trichomycetes in the black flies of Armenia. Main conclusions Although the Caucasus Region is noted for its high levels of endemism for plants and animals, including black flies, the gut symbiotes of black flies are all widespread species. The absence of endemic gut symbiotes in larval black flies might be explained by their lack of host specificity; an absence of host specificity would not constrain the geographical distribution of the symbiotes.     

Identification and characterization of a small molecule AMPK activator that treats key components of type 2 diabetes and the metabolic syndrome

AMP-activated protein kinase (AMPK) is a key sensor and regulator of intracellular and whole-body energy metabolism. We have identified a thienopyridone family of AMPK activators. A-769662 directly stimulated partially purified rat liver AMPK (EC₅₀ = 0.8 μM) and inhibited fatty acid synthesis in primary rat hepatocytes (IC₅₀ = 3.2 μM). Short-term treatment of normal Sprague Dawley rats with A-769662 decreased liver malonyl CoA levels and the respiratory exchange ratio, VCO₂/VO_2, indicating an increased rate of whole-body fatty acid oxidation. Treatment of ob/ob mice with 30 mg/kg b.i.d. A-769662 decreased hepatic expression of PEPCK, G6Pase, and FAS, lowered plasma glucose by 40%, reduced body weight gain and significantly decreased both plasma and liver triglyceride levels. These results demonstrate that small molecule-mediated activation of AMPK in vivo is feasible and represents a promising approach for the treatment of type 2 diabetes and the metabolic syndrome.     

Human cytomegalovirus immediate-early-gene expression disrupts embryogenesis in transgenic Drosophila

Intrauterine infection with human cytomegalovirus (HCMV) is the leading viral cause of birth defects involving the central nervous system. Due to the highly species specific nature of the virus, its course of natural infection cannot be studied in animal models. Here we introduce a novel transgenic Drosophila model system for studying the effects of the major viral regulatory genes, the immediate-early genes, on normal embryonic development. We show that ectopic expression of the immediate-early genes in Drosophila led to increased embryonic lethality manifested in disintegration of the embryos. Further analysis suggested that immediate-early gene expression interfered with adherens junction maintenance, leading to the disruption of embryonic epithelial integrity. Owing to the evolutionary conservation of developmental mechanisms from invertebrates to mammals, we anticipate that the studies in Drosophila will be relevant also to humans and will ultimately provide a versatile system for studying different aspects of viral-host interactions.     

Selective expansion of the beta-cell compartment in the pancreas of keratinocyte growth factor transgenic mice

Epithelial-mesenchymal interactions are essential for growth, differentiation, and regeneration of exocrine and endocrine cells in the pancreas. The keratinocyte growth factor (KGF) is derived from mesenchyme and has been shown to promote epithelial cell differentiation and proliferation in a paracrine fashion. Here, we have examined the effect of ectopic expression of KGF on pancreatic differentiation and proliferation in transgenic mice by using the proximal elastase promoter. KGF transgenic mice were generated following standard procedures and analyzed by histology, morphometry, immunohistochemistry, Western blot analysis, and glucose tolerance testing. In KGF transgenic mice, the number of islets, the average size of islets, and the relation of endocrine to exocrine tissue are increased compared with littermate controls. An expansion of the beta-cell population is responsible for the increase in the endocrine compartment. Ectopic expression of KGF results in proliferation of beta-cells and pancreatic duct cells most likely through activation of the protein kinase B (PKB)/Akt signaling pathway. Glucose tolerance and insulin secretion are impaired in transgenic animals. These results provide evidence that ectopic expression of KGF in acinar cells promotes the expansion of the beta-cell lineage in vivo through activation of the PKB/Akt pathway. Furthermore, the observed phenotype demonstrates that an increase in the beta-cell compartment does not necessarily result in an improved glucose tolerance in vivo.     

Dating the demise: neandertal extinction and the establishment of modern humans in the southern Caucasus

This paper considers the recent radiometric dating (¹⁴C-AMS, TL, ESR) of 76 late Middle and early Upper Paleolithic samples from Ortvale Klde Rockshelter, located in the Republic of Georgia. We present a critical evaluation of each date based on its stratigraphic and archaeological context, its pretreatment and contamination history, and its resulting accuracy and precision, the goal being to establish a sound chronology for the site. Only by systematically identifying aberrant dates within a data set and isolating them from further analysis can we hope to understand cultural and biological phenomena on an accurate temporal scale. Based on the strict discard protocol outlined here, we omit 25% of the dated samples from the analysis. The remaining data speak to the lengthy tenure of Neandertals in the region, but also to their relatively rapid demise and the establishment of modern human populations ∼38-34 ka ¹⁴C BP (42-39 ka cal BP_Hulu). We compare these chronometric data with those from the neighboring sites of Bronze and Dzudzuana caves, as well as Mezmaiskaya Cave, located in the northern Caucasus. While the lack of key contextual information limit our ability to subject these other data sets to the same critical evaluation procedure, they provide the first interregional temporal assessment of the Middle to Upper Paleolithic “transition,” the results of which suggest an initial expansion of modern humans into the southern Caucasus followed by expansion along the Black Sea coast and into the northern Caucasus.     

The role of heterogeneity in the persistence and prevalence of Sin Nombre virus in deer mice

Many diseases persist at a relatively low prevalence, seemingly close to extinction. For a chronic disease in a homogeneous population, reducing the transmission rate by a fraction proportional to the prevalence would be sufficient to eradicate the disease. This study examines how higher prevalence of the Sin Nombre virus in male deer mice (Peromyscus maniculatus) might contribute to disease persistence. Analyzing data from over 2,000 individual mice captured in 19 sites over 4 years, we found prevalences of 18.5% in males and 8.8% in females. By examining recaptures, we determined that males are more likely to contract the infection because of higher susceptibility or higher encounter rates. Comparing across 86 sampling periods, we found a higher proportion of males when population densities were low. A capture-recapture analysis indicates that males live longer than females. A mathematical model based on the measured parameters and population size trajectories suggests that the combined heterogeneity in encounters, susceptibility, and mortality may buffer the disease from extinction by concentrating disease in the subgroup most likely to transmit the disease. This buffering effect is not significantly stronger in a fluctuating population, indicating that these forms of heterogeneity might not be the key for disease persistence through host population bottlenecks.     

The multiple-wing-hairs gene encodes a novel GBD-FH3 domain-containing protein that functions both prior to and after wing hair initiation

The frizzled signaling/signal transduction pathway controls planar cell polarity (PCP) in both vertebrates and invertebrates. Epistasis experiments argue that in the Drosophila epidermis multiple wing hairs (mwh) acts as a downstream component of the pathway. The PCP proteins accumulate asymmetrically in pupal wing cells where they are thought to form distinct protein complexes. One is located on the distal side of wing cells and a second on the proximal side. This asymmetric protein accumulation is thought to lead to the activation of the cytoskeleton on the distal side, which in turn leads to each cell forming a single distally pointing hair. We identified mwh as CG13913, which encodes a novel G protein binding domain–formin homology 3 (GBD–FH3) domain protein. The Mwh protein accumulated on the proximal side of wing cells prior to hair formation. Unlike planar polarity proteins such as Frizzled or Inturned, Mwh also accumulated in growing hairs. This suggested that mwh had two temporally separate functions in wing development. Evidence for these two functions also came from temperature-shift experiments with a temperature-sensitive allele. Overexpression of Mwh inhibited hair initiation, thus Mwh acts as a negative regulator of the cytoskeleton. Our data argued early proximal Mwh accumulation restricts hair initiation to the distal side of wing cells and the later hair accumulation of Mwh prevents the formation of ectopic secondary hairs. This later function appears to be a feedback mechanism that limits cytoskeleton activation to ensure a single hair is formed.     

Commensal gut flora drives the expansion of proinflammatory CD4 T cells in the colonic lamina propria under normal and inflammatory conditions

We tested in B6 mice whether the local expansion of CD4 T cells producing proinflammatory cytokines including IL-17 (Th17 cells) in the colonic lamina propria (cLP) depends on the commensal microflora. High numbers of CD4 Th17 cells were found in the lamina propria of the ileum and colon but not the duodenum, jejunum, mesenteric lymph nodes, spleen, or liver of specific pathogen-free (SPF) mice. The microflora is required for the accumulation of cytokine (IL-17, IFN-gamma, TNF-alpha, IL-10)-producing CD4 T cells in the cLP because only low numbers of cytokine-producing cLP CD4 T cells were found in syngeneic (age- and sex-matched) germfree mice. The fraction of cLP Th17 cells was higher in (type I and type II) IFN- but not IL-4- or IL-12p40-deficient SPF congenics. cLP CD4 Th17 cells produce IL-17 but not IFN-gamma, TNF-alpha, IL-4, or IL-10. cLP CD4 Th17 cells accumulate locally in colitis induced by adoptive transfer of IFN-gamma+/+ or IFN-gamma-/- CD4 T cells into congenic SPF (but not germfree) RAG-/- hosts. In this colitis model, cLP CD4 T cells that "spontaneously" produce IL-17 progressively increase in number in the inflamed cLP, and increasing serum IL-17 levels appear as the disease progresses. Commensal bacteria-driven, local expansion of cLP CD4 Th17 cells may contribute to the pathogenesis of this inflammatory bowel disease.