RESUMO
Previous studies have shown that selection for starvation resistance in Drosophila melanogaster results in delayed eclosion and increased adult fat stores. It is assumed that these traits are caused by the starvation selection pressure, but its mechanism is unknown. We found that our starvation-selected (SS) population stores more fat during larval development and has extended larval development and pupal development time. Developmental checkpoints in the third instar associated with ecdysteroid hormone pulses are increasingly delayed. The delay in the late larval period seen in the SS population is indicative of reduced and delayed ecdysone signaling. An enzyme immunoassay for ecdysteroids (with greatest affinity to the metabolically active 20-hydroxyecdysone and the α-ecdysone precursor) confirmed that the SS population had reduced and delayed hormone production compared with that of fed control (FC) flies. Feeding third instar larvae on food supplemented with α-ecdysone partially rescued the developmental delay and reduced subsequent adult starvation resistance. This work suggests that starvation selection causes reduced and delayed production of ecdysteroids in the larval stage and affects the developmental delay phenotype that contributes to subsequent adult fat storage and starvation resistance.
Assuntos
Ecdisona , Ecdisteroides , Animais , Ecdisona/genética , Drosophila melanogaster/genética , Larva , FenótipoRESUMO
INTRODUCTION: Rates of cigarette use remain elevated among those living in rural areas. Depressive symptoms, risky alcohol use, and weight concerns frequently accompany cigarette smoking and may adversely affect quitting. Whether treatment for tobacco use that simultaneously addresses these issues affects cessation outcomes is uncertain. METHODS: The study was a multicenter, two-group, randomized controlled trial involving mostly rural veterans who smoke (N = 358) receiving treatment at one of five Veterans Affairs Medical Centers. The study randomly assigned participants to a tailored telephone counseling intervention or referral to their state tobacco quitline. Both groups received guideline-recommended smoking cessation pharmacotherapy, selected using a shared decision-making approach. The primary outcome was self-reported seven-day point prevalence abstinence (PPA) at three and six months. The study used salivary cotinine to verify self-reported quitting at six months. RESULTS: Self-reported PPA was significantly greater in participants assigned to Tailored Counseling at three (OR = 1.66; 95 % CI: 1.07-2.58) but not six (OR = 1.35; 95 % CI: 0.85-2.15) months. Post hoc subgroup analyses examining treatment group differences based on whether participants had a positive screen for elevated depressive symptoms, risky alcohol use, and/or concerns about weight gain indicated that the cessation benefit of Tailored Counseling at three months was limited to those with ≥1 accompanying concern (OR = 2.02, 95 % CI: 1.20-3.42). Biochemical verification suggested low rates of misreporting. CONCLUSIONS: A tailored smoking cessation intervention addressing concomitant risk factors enhanced short-term abstinence but did not significantly improve long-term quitting. Extending the duration of treatment may be necessary to sustain treatment effects.
Assuntos
Abandono do Hábito de Fumar , Tabagismo , Veteranos , Humanos , Tabagismo/terapia , Aconselhamento , Produtos do TabacoRESUMO
Autotaxin (ATX) facilitates the hydrolysis of lysophosphatidylcholine to lysophosphatidic acid (LPA), a bioactive phospholipid, which facilitates a diverse range of cellular effects in multiple tissue types. Abnormal LPA expression can lead to the progression of diseases such as cancer and fibrosis. Previously, we identified a potent ATX steroid-derived hybrid (partially orthosteric and allosteric) inhibitor which did not form interactions with the catalytic site. Herein, we describe the design, synthesis, and biological evaluation of a focused library of novel steroid-derived analogues targeting the bimetallic catalytic site, representing an entirely unique class of ATX inhibitors of type V designation, which demonstrate significant pathway-relevant biochemical and phenotypic biological effects. The current compounds modulated LPA-mediated ATX allostery and achieved indirect blockage of LPA1 internalization, in line with the observed reduction in downstream signaling cascades and chemotaxis induction. These novel type V ATX inhibitors represent a promising tool to inactivate the ATX-LPA signaling axis.