8 research outputs found
Evaluation and Recommendations on Good Clinical Laboratory Practice Guidelines for Phase IāIII Clinical Trials
Marcella Sarzotti-Kelsoe and colleagues harmonize various approaches to Good Clinical Laboratory Practice for clinical trials into a single set of recommendations
Neural precursor cell chain migration and division are regulated through different Ī²1 integrins
Proliferation and tangential migration of neural precursor cells are essential determinants of CNS development. We have established cell culture models of both these processes using neural precursor cells grown as neurospheres. The pattern of migration that we observe in these cells is homotypic and occurs in the absence of a glial or neuronal scaffold, and is therefore equivalent to that previously described as chain migration. To determine the role of integrins in proliferation and migration, we have analysed the expression pattern of integrins on neurosphere cells and then performed blocking peptide and antibody experiments. Neurosphere cells express five major integrins, Ī±5Ī²1, Ī±6AĪ²1, Ī±vĪ²1, Ī±vĪ²5 and Ī±vĪ²8 and, in addition, express low levels of Ī±6BĪ²1. Chain migration is inhibited by blocking the Ī±6Ī²1 integrin. Proliferation, by contrast, is inhibited by blocking the other Ī²1 integrins, Ī±vĪ²1 and Ī±5Ī²1. These results show that integrins are important regulators of neural precursor cell behaviour, with distinct Ī²1 integrins regulating proliferation and migration. They also demonstrate a novel role for the Ī±6Ī²1 integrin in the cell-cell interactions underlying homotypic chain migration
Structural mutants of dengue virus 2 transmembrane domains exhibit host-range phenotype
Abstract Background There are over 700 known arboviruses and at least 80 immunologically distinct types that cause disease in humans. Arboviruses are transmitted among vertebrates by biting insects, chiefly mosquitoes and ticks. These viruses are widely distributed throughout the world, depending on the presence of appropriate hosts (birds, horses, domestic animals, humans) and vectors. Mosquito-borne arboviruses present some of the most important examples of emerging and resurgent diseases of global significance. Methods A strategy has been developed by which host-range mutants of Dengue virus can be constructed by generating deletions in the transmembrane domain (TMD) of the E glycoprotein. The host-range mutants produced and selected favored growth in the insect hosts. Mouse trials were conducted to determine if these mutants could initiate an immune response in an in vivo system. Results The DV2 E protein TMD defined as amino acids 452SWTMKILIGVIITWIG467 was found to contain specific residues which were required for the production of this host-range phenotype. Deletion mutants were found to be stable in vitro for 4 sequential passages in both host cell lines. The host-range mutants elicited neutralizing antibody above that seen for wild-type virus in mice and warrant further testing in primates as potential vaccine candidates. Conclusions Novel host-range mutants of DV2 were created that have preferential growth in insect cells and impaired infectivity in mammalian cells. This method for creating live, attenuated viral mutants that generate safe and effective immunity may be applied to many other insect-borne viral diseases for which no current effective therapies exist.</p
CGI-58/ABHD5-Derived Signaling Lipids Regulate Systemic Inflammation and Insulin Action
Mutations of comparative gene identification 58 (CGI-58) in humans cause Chanarin-Dorfman syndrome, a rare autosomal recessive disease in which excess triacylglycerol (TAG) accumulates in multiple tissues. CGI-58 recently has been ascribed two distinct biochemical activities, including coactivation of adipose triglyceride lipase and acylation of lysophosphatidic acid (LPA). It is noteworthy that both the substrate (LPA) and the product (phosphatidic acid) of the LPA acyltransferase reaction are wellknown signaling lipids. Therefore, we hypothesized that CGI-58 is involved in generating lipid mediators that regulate TAG metabolism and insulin sensitivity. Here, we show that CGI-58 is required for the generation of signaling lipids in response to inflammatory stimuli and that lipid second messengers generated by CGI-58 play a critical role in maintaining the balance between inflammation and insulin action. Furthermore, we show that CGI- 58 is necessary for maximal TH1 cytokine signaling in the liver. This novel role for CGI-58 in cytokine signaling may explain why diminished CGI-58 expression causes severe hepatic lipid accumulation yet paradoxically improves hepatic insulin action. Collectively, these findings establish that CGI-58 provides a novel source of signaling lipids. These findings contribute insight into the basic mechanisms linking TH1 cytokine signaling to nutrient metabolism
The Serine Hydrolase ABHD6 Is a Critical Regulator of the Metabolic Syndrome
The serine hydrolase Ī±/Ī² hydrolase domain 6 (ABHD6) has recently been implicated as a key lipaseĀ for the endocannabinoid 2-arachidonylglycerol (2-AG) in the brain. However, the biochemical and physiological function for ABHD6 outside of the central nervous system has not been established. To address this, we utilized targeted antisense oligonucleotides (ASOs) to selectively knock down ABHD6 inĀ peripheral tissues in order to identify inĀ vivo substrates and understand ABHD6ās role in energy metabolism. Here, we show that selective knockdown of ABHD6 in metabolic tissues protects mice from high-fat-diet-induced obesity, hepatic steatosis, and systemic insulin resistance. Using combined inĀ vivo lipidomic identification andĀ inĀ vitro enzymology approaches, we show that ABHD6 can hydrolyze several lipid substrates, positioning ABHD6 at the interface of glycerophospholipid metabolism and lipid signal transduction. Collectively, these data suggest that ABHD6 inhibitors may serve as therapeutics for obesity, nonalcoholic fatty liver disease, and type II diabetes