Circadian pacemaking requires the orderly synthesis, posttranslational modification, and degradation of clock proteins. In mammals, mutations in casein kinase 1 (CK1) ε or δ can alter the circadian period, but the particular functions of the WT isoforms within the pacemaker remain unclear. We selectively targeted WT CK1ε and CK1δ using pharmacological inhibitors (PF-4800567 and PF-670462, respectively) alongside genetic knockout and knockdown to reveal that CK1 activity is essential to molecular pacemaking. Moreover, CK1δ is the principal regulator of the clock period: pharmacological inhibition of CK1δ, but not CK1ε, significantly lengthened circadian rhythms in locomotor activity in vivo and molecular oscillations in the suprachiasmatic nucleus (SCN) and peripheral tissue slices in vitro. Period lengthening mediated by CK1δ inhibition was accompanied by nuclear retention of PER2 protein both in vitro and in vivo. Furthermore, phase mapping of the molecular clockwork in vitro showed that PF-670462 treatment lengthened the period in a phase-specific manner, selectively extending the duration of PER2-mediated transcriptional feedback. These findings suggested that CK1δ inhibition might be effective in increasing the amplitude and synchronization of disrupted circadian oscillators. This was tested using arrhythmic SCN slices derived from Vipr2 −/− mice, in which PF-670462 treatment transiently restored robust circadian rhythms of PER2::Luc bioluminescence. Moreover, in mice rendered behaviorally arrhythmic by the Vipr2 −/− mutation or by constant light, daily treatment with PF-670462 elicited robust 24-h activity cycles that persisted throughout treatment. Accordingly, selective pharmacological targeting of the endogenous circadian regulator CK1δ offers an avenue for therapeutic modulation of perturbed circadian behavior.circadian clock | suprachiasmatic nucleus | period protein | Tau mutation | pacemaking

Lithium salt has been widely used in treatment of Bipolar Disorder, a mental disturbance associated with circadian rhythm disruptions. Lithium mildly but consistently lengthens circadian period of behavioural rhythms in multiple organisms. To systematically address the impacts of lithium on circadian pacemaking and the underlying mechanisms, we measured locomotor activity in mice in vivo following chronic lithium treatment, and also tracked clock protein dynamics (PER2::Luciferase) in vitro in lithium-treated tissue slices/cells. Lithium lengthens period of both the locomotor activity rhythms, as well as the molecular oscillations in the suprachiasmatic nucleus, lung tissues and fibroblast cells. In addition, we also identified significantly elevated PER2::LUC expression and oscillation amplitude in both central and peripheral pacemakers. Elevation of PER2::LUC by lithium was not associated with changes in protein stabilities of PER2, but instead with increased transcription of Per2 gene. Although lithium and GSK3 inhibition showed opposing effects on clock period, they acted in a similar fashion to up-regulate PER2 expression and oscillation amplitude. Collectively, our data have identified a novel amplitude-enhancing effect of lithium on the PER2 protein rhythms in the central and peripheral circadian clockwork, which may involve a GSK3-mediated signalling pathway. These findings may advance our understanding of the therapeutic actions of lithium in Bipolar Disorder or other psychiatric diseases that involve circadian rhythm disruptions.

Summary The nuclear receptor REV-ERBα is a key negative-feedback regulator of the biological clock. REV-ERBα binds to ROR elements of the Bmal1 (Arntl) promoter and represses Bmal1 transcription. This stabilizing negative loop is important for precise control of the circadian pacemaker. In the present study, we identified a novel synthetic REV-ERBα ligand, which enhances the recruitment of nuclear receptor co-repressor (NCoR) to REV-ERBα. In order to explore REV-ERBα action on resetting responses of the molecular clock, we first established the rhythmic transcription profile and expression level of REV-ERBα in Rat-1 fibroblasts. When applied at different phases of the circadian oscillation to cell models containing stably transfected Bmal1::Luc or Per2::Luc, the REV-ERBα ligand induced phase-dependent bi-directional phase shifts. When the phase changes were plotted against time, a clear phase response curve was revealed, with a significant peak-to-trough amplitude of ca. 5 hours. The phase-resetting effect was also observed when the compound was applied to primary lung fibroblasts and ectopic lung slices from transgenic PER2::Luc mice. Therefore, similar regulation of REV-ERBα function by endogenous ligands, such as heme, is likely to be an important mechanism for clock resetting. In addition, we identify a new means to generate phasic shifts in the clock.

ObjectiveTo compare the outcomes of routine provider-initiated HIV testing and counselling (PITC) and oral rapid HIV testing for dental clinic outpatients in a hospital.DesignWe employed a case–control study design and recruited dental outpatients into routine serum-based and oral rapid testing groups. We compared the acceptance, completion and result notification rate between groups.SettingA dental outpatient clinic in the Yuxi People's Hospital, Yunnan.ParticipantsA total of 758 and 816 dental outpatients were enrolled for routine and oral rapid testing, respectively.ResultsThe percentage of participants willing to receive routine HIV testing was 28.1% (95% CI 24.9% to 31.3%) and 96.1% (95% CI 94.8% to 97.4%, χ2=186.4, p<0.001) for the rapid testing. Among accepted participants, the percentage of participants who received HIV testing was 26.8% (95% CI 20.9% to 32.7%) in the routine testing group and 100.0% in the oral rapid HIV testing group (χ2=77.5, p<0.001). About 93.0% of routine testers returned for the test results on the next day, whereas all rapid testers received their test results on the same day (χ2=34.6, p<0.001). These correspond to an overall completion rate of 7.0% (95% CI 5.2% to 8.8%) and 96.1% (95% CI 94.8% to 97.4%, p<0.001), respectively. Among the 545 patients who declined routine serum-based HIV testing, the main reasons included, an unnecessary hassle (254/545, 46.6%), having been previously tested (124/545, 22.8%) and self-perceived low risk of HIV infection (103/545, 18.9%). In contrast, only 32 individuals declined oral rapid testing, and having received a previous test was the primary reason. Three patients in the rapid testing group were later confirmed HIV-positive, yielding an HIV prevalence of 0.38%.ConclusionOral rapid HIV testing is a feasible and efficient approach in a clinical setting.

Purpose: The purpose of this study was to evaluate the relationship between apolipoprotein A-IV (apoA-IV) plasma concentrations and acute coronary syndrome (ACS). Methods: Plasma apoA-IV concentrations were measured in 115 patients with different types of ACS and in 68 gender- and age-matched control subjects using Enzyme-Linked Immunosorbent Assay (ELISA) kits. The clinical data were collected by an internist, who was blinded to plasma apoA-IV concentrations. Results: Plasma apoA-IV levels in ACS patients were significantly decreased compared to the levels in control subjects (437.0 ± 157.5 μg/mL vs. 590.2 ± 183.7 μg/mL, P < 0.001). An statistically significant decreasing trend of plasma apoA-IV levels from the control subjects, to patients with unstable angina pectoris (UAP) (457.3 ± 152.9 μg/mL), to patients with acute myocardial infarction (AMI) (311.7 ± 127.8 μg/mL), was observed. Moreover, plasma apoA-IV level was negatively associated with New York Heart Association (NYHA) functional class. NYHA class II (467.2 ± 142.1 μg/mL, P < 0.001) and class III/IV (368.1 ± 170.8 μg/mL, P < 0.001) patients had statistically decreased levels of plasma apoA-IV when compared to the control subjects. A stepwise multivariate regression analysis identified types of ACS, NYHA classes, and plasma fibrinogen levels as the most important determinants of plasma apoA-IV levels in ACS patients. Conclusions: Low plasma apoA-IV levels are associated with ACS, and plasma apoA-IV levels may be a potential treatment target for ACS patients.