A metazoan-specific C-terminal motif in EXC-4 and Gα-Rho/Rac signaling regulate cell outgrowth during tubulogenesis in C. elegans.

Chloride intracellular channels (CLICs) are conserved proteins for which the cellular and molecular functions remain mysterious. An important insight into CLIC function came from the discovery that Caenorhabditis elegans EXC-4/CLIC regulates morphogenesis of the excretory canal (ExCa) cell, a single-cell tube. Subsequent work showed that mammalian CLICs regulate vascular development and angiogenesis, and human CLIC1 can rescue exc-4 mutants, suggesting conserved function in biological tube formation (tubulogenesis) and maintenance. However, the cell behaviors and signaling pathways regulated by EXC-4/CLICs during tubulogenesis in vivo remain largely unknown. We report a new exc-4 mutation, affecting a C-terminal residue conserved in virtually all metazoan CLICs, that reveals a specific role for EXC-4 in ExCa outgrowth. Cell culture studies suggest a function for CLICs in heterotrimeric G protein (Gα/ß/γ)-Rho/Rac signaling, and Rho-family GTPases are common regulators of cell outgrowth. Using our new exc-4 mutant, we describe a previously unknown function for Gα-encoding genes (gpa-12/Gα12/13, gpa-7/Gαi, egl-30/Gαq and gsa-1/Gαs), ced-10/Rac and mig-2/RhoG in EXC-4-mediated ExCa outgrowth. Our results demonstrate that EXC-4/CLICs are primordial players in Gα-Rho/Rac-signaling, a pathway that is crucial for tubulogenesis in C. elegans and in vascular development.

Novel feature selection methods for construction of accurate epigenetic clocks.

Epigenetic clocks allow us to accurately predict the age and future health of individuals based on the methylation status of specific CpG sites in the genome and are a powerful tool to measure the effectiveness of longevity interventions. There is a growing need for methods to efficiently construct epigenetic clocks. The most common approach is to create clocks using elastic net regression modelling of all measured CpG sites, without first identifying specific features or CpGs of interest. The addition of feature selection approaches provides the opportunity to optimise the identification of predictive CpG sites. Here, we apply novel feature selection methods and combinatorial approaches including newly adapted neural networks, genetic algorithms, and 'chained' combinations. Human whole blood methylation data of ~470,000 CpGs was used to develop clocks that predict age with R2 correlation scores of greater than 0.73, the most predictive of which uses 35 CpG sites for a R2 correlation score of 0.87. The five most frequent sites across all clocks were modelled to build a clock with a R2 correlation score of 0.83. These two clocks are validated on two external datasets where they maintain excellent predictive accuracy. When compared with three published epigenetic clocks (Hannum, Horvath, Weidner) also applied to these validation datasets, our clocks outperformed all three models. We identified gene regulatory regions associated with selected CpGs as possible targets for future aging studies. Thus, our feature selection algorithms build accurate, generalizable clocks with a low number of CpG sites, providing important tools for the field.

Estimation of Admission D-dimer Cut-off Value to Predict Venous Thrombotic Events in Hospitalized COVID-19 Patients: Analysis of the SEMI-COVID-19 Registry.

BACKGROUND: Venous thrombotic events (VTE) are frequent in COVID-19, and elevated plasma D-dimer (pDd) and dyspnea are common in both entities. OBJECTIVE: To determine the admission pDd cut-off value associated with in-hospital VTE in patients with COVID-19. METHODS: Multicenter, retrospective study analyzing the at-admission pDd cut-off value to predict VTE and anticoagulation intensity along hospitalization due to COVID-19. RESULTS: Among 9386 patients, 2.2% had VTE: 1.6% pulmonary embolism (PE), 0.4% deep vein thrombosis (DVT), and 0.2% both. Those with VTE had a higher prevalence of tachypnea (42.9% vs. 31.1%; p = 0.0005), basal O2 saturation <93% (45.4% vs. 33.1%; p = 0.0003), higher at admission pDd (median [IQR]: 1.4 [0.6-5.5] vs. 0.6 [0.4-1.2] µg/ml; p < 0.0001) and platelet count (median [IQR]: 208 [158-289] vs. 189 [148-245] platelets × 109/L; p = 0.0013). A pDd cut-off of 1.1 µg/ml showed specificity 72%, sensitivity 49%, positive predictive value (PPV) 4%, and negative predictive value (NPV) 99% for in-hospital VTE. A cut-off value of 4.7 µg/ml showed specificity of 95%, sensitivity of 27%, PPV of 9%, and NPV of 98%. Overall mortality was proportional to pDd value, with the lowest incidence for each pDd category depending on anticoagulation intensity: 26.3% for those with pDd >1.0 µg/ml treated with prophylactic dose (p < 0.0001), 28.8% for pDd for patients with pDd >2.0 µg/ml treated with intermediate dose (p = 0.0001), and 31.3% for those with pDd >3.0 µg/ml and full anticoagulation (p = 0.0183). CONCLUSIONS: In hospitalized patients with COVID-19, a pDd value greater than 3.0 µg/ml can be considered to screen VTE and to consider full-dose anticoagulation.

SUMOylation determines the voltage required to activate cardiac IKs channels.

IKs channels open in response to depolarization of the membrane voltage during the cardiac action potential, passing potassium ions outward to repolarize ventricular myocytes and end each beat. Here, we show that the voltage required to activate IKs channels depends on their covalent modification by small ubiquitin-like modifier (SUMO) proteins. IKs channels are comprised of four KCNQ1 pore-forming subunits, two KCNE1 accessory subunits, and up to four SUMOs, one on Lys424 of each KCNQ1 subunit. Each SUMO shifts the half-maximal activation voltage (V1/2) of IKs ∼ +8 mV, producing a maximal +34-mV shift in neonatal mouse cardiac myocytes or Chinese hamster ovary (CHO) cells expressing the mouse or human subunits. Unexpectedly, channels formed without KCNE1 carry at most two SUMOs despite having four available KCNQ1-Lys424 sites. SUMOylation of KCNQ1 is KCNE1 dependent and determines the native attributes of cardiac IKs in vivo.

Factors Associated with Incomplete Endodontic Care.

INTRODUCTION: Incomplete endodontic treatment has been associated with detrimental health outcomes. METHODS: This retrospective study reviewed charts of patients receiving endodontic care over a 1-year period at the Postgraduate Endodontic Clinic at Rutgers School of Dental Medicine, Newark, NJ, to assess whether factors such as receipt of palliative endodontic care and demographic factors were associated with completion, or noncompletion, of initial nonsurgical root canal therapy (RCT). RESULTS: A total of 1806 patient charts met the study inclusion criteria. With descriptive statistics and bivariate analysis, the variables of palliative care, Medicaid recipient, age group, and distance from the clinic were significantly associated with RCT completion (P < .05). In the binary logistic regression with all independent variables, palliative care and age group variables were the significant factors (P < .05). Patients who had no palliative care had 8.5 times the odds of completing RCT than patients who had received palliative care. The age group of 18-35 years had 0.59 times the odds of complete RCT than the age group <18 years. CONCLUSIONS: Incomplete nonsurgical endodontic treatment is highly associated with the receipt of prior palliative care. Further research is indicated to investigate additional factors that may influence patient completion of endodontic care and opportunities to improve public health care program design to obtain optimal patient-centered outcomes.

Prey capture behavior of native vs. nonnative fishes: a case study from the Colorado River drainage basin (USA).

The Colorado River drainage basin is home to a diverse but imperiled fish fauna; one putative challenge facing natives is competition with nonnatives. We examined fishes from Colorado River tributaries to address the following questions: Do natives and nonnatives from the same trophic guild consume the same prey items? Will a given species alter its behavior when presented with different prey types? Do different species procure the same prey types via similar feeding behaviors? Roundtail chub (Gila robusta) and smallmouth bass (Micropterus dolomieu), midwater predators, and Sonora sucker (Catostomus insignis) and common carp (Cyprinus carpio), benthic omnivores, were offered six ecologically relevant prey types in more than 600 laboratory trials. Native species consumed a broader array of prey than nonnatives, and species from a given trophic guild demonstrated functional convergence in key aspects of feeding behavior. For example, roundtail chub and smallmouth bass consume prey attached to the substrate by biting, then ripping the prey from its point of attachment; in contrast, Sonora sucker remove attached prey via scraping. When presented with different prey types, common carp, roundtail chub, and smallmouth bass altered their prey capture behavior by modifying strike distance, gape, and angle of attack. Gape varied among the species examined here, with smallmouth bass demonstrating the largest functional and anatomical gape at a given body size. Because fish predators are gape-limited, smallmouth bass will be able to consume a variety of large prey items in the wild, including large, invasive crayfish and young roundtail chub-their presumptive trophic competitors.