RESUMO
Astrocytes are multi-functional glial cells in the central nervous system that play critical roles in modulation of metabolism, extracellular ion and neurotransmitter levels, and synaptic plasticity. Astrocyte-derived signaling molecules mediate many of these modulatory functions of astrocytes, including vesicular release of ATP. In the present study, we used a unique genetic mouse model to investigate the functional significance of astrocytic exocytosis of ATP. Using primary cultured astrocytes, we show that loss of vesicular nucleotide transporter (Vnut), a primary transporter responsible for loading cytosolic ATP into the secretory vesicles, dramatically reduces ATP loading into secretory lysosomes and ATP release, without any change in the molecular machinery of exocytosis or total intracellular ATP content. Deletion of astrocytic Vnut in adult mice leads to increased anxiety, depressive-like behaviors, and decreased motivation for reward, especially in females, without significant impact on food intake, systemic glucose metabolism, cognition, or sociability. These behavioral alterations are associated with significant decreases in the basal extracellular dopamine levels in the nucleus accumbens. Likewise, ex vivo brain slices from these mice show a strong trend toward a reduction in evoked dopamine release in the nucleus accumbens. Mechanistically, the reduced dopamine signaling we observed is likely due to an increased expression of monoamine oxidases. Together, these data demonstrate a key modulatory role of astrocytic exocytosis of ATP in anxiety, depressive-like behavior, and motivation for reward, by regulating the mesolimbic dopamine circuitry.
RESUMO
The bacterial SOS response plays a key role in adaptation to DNA damage, including genomic stress caused by antibiotics. SOS induction begins when activated RecA*, an oligomeric nucleoprotein filament that forms on single-stranded DNA, binds to and stimulates autoproteolysis of the repressor LexA. Here, we present the structure of the complete Escherichia coli SOS signal complex, constituting full-length LexA bound to RecA*. We uncover an extensive interface unexpectedly including the LexA DNA-binding domain, providing a new molecular rationale for ordered SOS gene induction. We further find that the interface involves three RecA subunits, with a single residue in the central engaged subunit acting as a molecular key, inserting into an allosteric binding pocket to induce LexA cleavage. Given the pro-mutagenic nature of SOS activation, our structural and mechanistic insights provide a foundation for developing new therapeutics to slow the evolution of antibiotic resistance.
RESUMO
Background: The majority of randomized controlled trials (RCTs) investigating venous thromboembolism (VTE) prophylaxis in patients with cancer involve commercial sponsorship. Commercial sponsorship overcomes feasibility limitations inherent in RCTs, such as recruitment and funding, but has attracted scrutiny for its potential for bias. Objectives: In RCTs of VTE prophylaxis in patients with cancer, how do trial characteristics compare between commercially sponsored RCTs and noncommercially sponsored RCTs? Methods: Medline, Embase, and Cochrane Central Register of Controlled Trials were searched for RCTs that investigated at least 1 pharmacologic intervention for VTE prophylaxis in adult patients with cancer. Screening and data extraction were conducted by independent reviewers. Outcomes included trial characteristics, reporting of favorable outcomes, protocol-manuscript discrepancies, and appraisal of spin. Outcomes were compared using the independent t-test, Mann-Whitney U-test, Pearson chi-squared test, and Fisher's exact test. Logistic regression was performed to identify factors associated with possible bias. Results: Of the 54 trials analyzed, 34 (63%) reported commercial sponsorship. Commercial sponsorship was not associated with the reporting of favorable outcomes, presence of spin, retrospective registration, or protocol-manuscript discrepancy. Spin was most prevalent in the abstract conclusions (9 out of 17 [53.3%]) and manuscript conclusions (8 out of 17 [46.7%]).Commercially sponsored trials had a higher rate of intention-to-treat analysis. Noncommercially sponsored trials were more likely to report retrospective registration of trial protocol and the use of composite primary outcomes. Conclusion: There were few significant differences between trial characteristics, suggesting that the evidence from commercially sponsored trials investigating VTE prophylaxis in patients with cancer is unlikely to be subject to bias attributable to commercial sponsorship.
RESUMO
Background: Lung metastasectomy is an accepted treatment modality worldwide. Whether the addition of lymph node dissection to the procedure is useful remains, however, unknown. Methods: We performed a systematic review of the literature analyzing MEDLINE, Embase, until 31st October 2021. We included all studies which met the inclusion criteria aiming to determine if the addition of lymph node tissue dissection/sampling to lung metastasectomy offers survival benefits when compared to patients who do receive lymph node tissue dissection. Secondary outcomes were 3- and 5-year overall survival (OS) and disease-free survival (DFS). Each study was assessed for risk of bias. The data collected from the included studies were pooled using reconstruction of individual-level patient data and pooling of reported 5-year odds ratios (ORs). Interstudy heterogeneity was estimated with visual inspection of forest plots and calculation of the I2 inconsistency statistic. Results: We found 11 eligible studies that included a total of 3,310 patients. The most common primary tumor type was colorectal cancer (1,740 patients) and the most commonly performed operative procedure was wedge resection (57%) followed by lobectomy (39%). When resection status was reported, R0 resection was achieved in 90% of the cases. Nine studies did not show a statistically significant effect of lymph nodes dissection or sampling on the 5-year OS with a pooled hazard ratio (HR) of 0.94 [95% confidence interval (CI): 0.82, 1.08; I2=26%; 95% prediction interval (PI): 0.70, 1.24]. Regarding DFS, the pooled HR 0.60 (95% CI: 0.44, 0.80; I2=31%; 95% PI: 0.12, 2.09). Conclusions: The addition of lymph node tissue dissection during lung metastasectomy was not associated with a significant benefit in OS and showed a slight tendency towards a better DFS.