Light-induced multi-site phosphorylation attenuates the activity of White Collar Complex

The White Collar Complex (WCC) is a transcription factor and light receptor formed by two subunits. Only White Collar-1 (WC 1) has a light receptor domain but both WC-1 and White Collar-2 (WC-2) have zinc finger DNA binding domains. In the negative feedback loop of the circadian clock in Neurospora crassa, WCC is the positive element that drives the clock and synchronizes it with the external cycle of day and night. According to these two functions, there are two groups of target genes, the clock-controlled genes (ccgs) and the light-inducible genes. The latter subset is activated by binding of the light-activated WCC (L-WCC). FREQUENCY (FRQ) is a target of WCC and is the negative element in the feedback loop of the circadian clock in N. crassa. FRQ recruits Casein Kinase 1a (CK1a) to inactivate WCC by phosphorylation. This circadian phosphorylation also stabilizes WCC, so the feedback of FRQ on WCC is both negative and positive. The light-induced activity of L-WCC is regulated by phosphorylation as well, the mechanism of this light-induced phosphorylation is the subject of this study. L-WCC was proven to consist of two molecules WC-1 and two molecules WC-2. In this work, 34 phosphorylation sites of WC-1 (27 new) and 23 sites of WC-2 (22 new) have been determined. Neither phosphorylation of a protein domain, nor light- or dark-specific phosphorylation were found. There seems to be a pool of poorly and differently phosphorylated WCC molecules in the dark, and light increases the phosphorylation of each molecule. The search for kinase(s) revealed that FRQ also mediates the light-induced phosphorylation of WCC by CK1a and the activity of other kinases is presumed. Phosphorylation site mutants of WC 2 revealed a gradual reduction of the transcriptional activity of WCC, a regulatory compensation of WC-1 and WC-2 and suggested identity of circadian and light-induced phosphorylation. Phosphorylation sites followed by proline are overrepresented on WCC and were shown to be a trigger for FRQ-mediated phosphorylation. Other triggers of phosphorylation of WCC are DNA-binding and most likely light-induced dimerization. DNA-binding brings WCC close to the proline-directed kinases of the transcriptional machinery (TM). It was hypothesized that the TM feeds back on the active WCC to mark it for subsequent, activity-attenuating, FRQ-mediated phosphorylation. A recently published study of the circadian phosphorylation of WCC largely confirms these results but does not touch the topic of proline-directed phosphorylation although these sites are overrepresented in that study as well. Proline-directed phosphorylation is also overrepresented on CLOCK, the WCC ortholog in Drosophila melanogaster, further supporting the hypothesis of a feedback of the TM on WCC

Bayesian Semiparametric Estimation of Heterogeneous Effects in Matched Case-Control Studies with an Application to Alzheimer's Disease and Heat

Epidemiological approaches for examining human health responses to environmental exposures in observational studies often control for confounding by implementing clever matching schemes and using statistical methods based on conditional likelihood. Nonparametric regression models have surged in popularity in recent years as a tool for estimating individual-level heterogeneous effects, which provide a more detailed picture of the exposure-response relationship but can also be aggregated to obtain improved marginal estimates at the population level. In this work we incorporate Bayesian additive regression trees (BART) into the conditional logistic regression model to identify heterogeneous effects of environmental exposures in a case-crossover design. Conditional logistic BART (CL-BART) utilizes reversible jump Markov chain Monte Carlo to bypass the conditional conjugacy requirement of the original BART algorithm. Our work is motivated by the growing interest in identifying subpopulations more vulnerable to environmental exposures. We apply CL-BART to a study of the impact of heatwaves on people with Alzheimer's Disease in California and effect modification by other chronic conditions. Through this application, we also describe strategies to examine heterogeneous odds ratios through variable importance, partial dependence, and lower-dimensional summaries. CL-BART is available in the clbart R package.Comment: 36 pages, 5 figure

Neuroblastoma in a 55-Year-Old Patient: A Case Report

Background: Neuroblastomas account for 97% of all neuroblastic tumors and for approximately 15% of all pediatric cancer fatalities. However, in adults neuroblastoma is a very rare finding. Case Report: Here, we present the case of a 55-year-old patient who was diagnosed with neuroblastoma stage IV one year after the false diagnosis of a non-secretory multiple myeloma. Results: The patient received six cycles of a chemotherapy protocol with cisplatin, etoposide and vindesine alternating with vincristine, dacarbazine, ifosfamide and doxorubicin, but the response to treatment was insufficient (stable disease). Conclusion: The standard chemotherapy protocols used for children are not sufficient for adult patients. Different treatment approaches are needed to improve the prognosis of adult patients with neuroblastoma

Predicting the need for renal replacement therapy using a vascular occlusion test and tissue oxygen saturation in patients in the early phase of multiorgan dysfunction syndrome

Background: Acute kidney injury (AKI) is associated with an increased mortality in critically ill patients, especially in patients with multiorgan dysfunction syndrome (MODS). In daily clinical practice, the grading of AKI follows the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. In most cases, a relevant delay occurs frequently between the onset of AKI and detectable changes in creatinine levels as well as clinical symptoms. The aim of the present study was to examine whether a near infrared spectroscopy (NIRS)-based, non-invasive ischemia–reperfusion test (vascular occlusion test (VOT)) together with unprovoked (under resting conditions) tissue oxygen saturation (StO 2 ) measurements, contain prognostic information in the early stage of MODS regarding the developing need for renal replacement therapy (RRT). Methods: Within a period of 18 months, patients at the medical intensive care unit of a tertiary university hospital with newly developed MODS (≤24 h after diagnosis, APACHE II score ≥20) were included in our study. The VOT occlusion slope (OS) and recovery slope (RS) were recorded in addition to unprovoked StO 2 . StO 2 was determined non-invasively in the area of the thenar muscles using a bedside NIRS device. The VOT was carried out by inflating a blood pressure cuff on the upper arm. AKI stages were determined by the changes in creatinine levels, urinary output, and/or the need for RRT according to KDIGO. Results: 56 patients with MODS were included in the study (aged 62.5 ± 14.4 years, 40 men and 16 women, APACHE II score 34.5 ± 6.4). Incidences of the different AKI stages were: no AKI, 16.1% ( n = 9); AKI stage I, 19.6% ( n = 11); AKI stage II, 25% ( n = 14); AKI stage III, 39.3% ( n = 22). Thus, 39.3% of the patients ( n = 22) developed the need for renal replacement therapy (AKI stage III). These patients had a significantly higher mortality over 28 days (RRT, 72% ( n = 16/22) vs. no RRT, 44% ( n = 15/34); p = 0.03). The mean unprovoked StO 2 of all patients at baseline was 81.7 ± 11.1%, and did not differ between patients with or without the need for RRT. Patients with RRT showed significantly weaker negative values of the OS (−9.1 ± 3.7 vs. −11.7 ± 4.1%/min, p = 0.01) and lower values for the RS (1.7 ± 0.9 vs. 2.3 ± 1.6%/s, p = 0.02) compared to non-dialysis patients. Consistent with these results, weaker negative values of the OS were found in higher AKI stages (no AKI, −12.7 ± 4.1%/min; AKI stage I, −11.5 ± 3.0%/min; AKI stage II, −11.1 ± 3.3%/min; AKI stage III, −9.1 ± 3.7%/min; p = 0.021). Unprovoked StO 2 did not contain prognostic information regarding the AKI stages. Conclusions: The weaker negative values of the VOT parameter OS are associated with an increased risk of developing AKI and RRT, and increased mortality in the early phase of MODS, while unprovoked StO 2 does not contain prognostic information in that regard

Factors Affecting the Association between Ambient Concentrations and Personal Exposures to Particles and Gases

Results from air pollution exposure assessment studies suggest that ambient fine particles [particulate matter with aerodynamic diameter ≤ 2.5 μg (PM(2.5))], but not ambient gases, are strong proxies of corresponding personal exposures. For particles, the strength of the personal–ambient association can differ by particle component and level of home ventilation. For gases, however, such as ozone (O(3)), nitrogen dioxide (NO(2)), and sulfur dioxide (SO(2)), the impact of home ventilation on personal–ambient associations is untested. We measured 24-hr personal exposures and corresponding ambient concentrations to PM(2.5), sulfate (SO(4)(2−)), elemental carbon, O(3), NO(2), and SO(2) for 10 nonsmoking older adults in Steubenville, Ohio. We found strong associations between ambient particle concentrations and corresponding personal exposures. In contrast, although significant, most associations between ambient gases and their corresponding exposures had low slopes and R(2) values; the personal–ambient NO(2) association in the fall season was moderate. For both particles and gases, personal–ambient associations were highest for individuals spending most of their time in high- compared with low-ventilated environments. Cross-pollutant models indicated that ambient particle concentrations were much better surrogates for exposure to particles than to gases. With the exception of ambient NO(2) in the fall, which showed moderate associations with personal exposures, ambient gases were poor proxies for both gas and particle exposures. In combination, our results suggest that a) ventilation may be an important modifier of the magnitude of effect in time-series health studies, and b) results from time-series health studies based on 24-hr ambient concentrations are more readily interpretable for particles than for gases