Extracellular Protons Inhibit Charge Immobilization in the Cardiac Voltage-Gated Sodium Channel

AbstractLow pH depolarizes the voltage-dependence of cardiac voltage-gated sodium (NaV1.5) channel activation and fast inactivation and destabilizes the fast-inactivated state. The molecular basis for these changes in protein behavior has not been reported. We hypothesized that changes in the kinetics of voltage sensor movement may destabilize the fast-inactivated state in NaV1.5. To test this idea, we recorded NaV1.5 gating currents in Xenopus oocytes using a cut-open voltage-clamp with extracellular solution titrated to either pH 7.4 or pH 6.0. Reducing extracellular pH significantly depolarized the voltage-dependence of both the QON/V and QOFF/V curves, and reduced the total charge immobilized during depolarization. We conclude that destabilized fast-inactivation and reduced charge immobilization in NaV1.5 at low pH are functionally related effects

Psychotic experiences, working memory, and the developing brain: a multimodal neuroimaging study

Psychotic experiences (PEs) occur in the general population, especially in children and adolescents, and are associated with poor psychosocial outcomes, impaired cognition, and increased risk of transition to psychosis. It is unknown how the presence and persistence of PEs during early adulthood affects cognition and brain function. The current study assessed working memory as well as brain function and structure in 149 individuals, with and without PEs, drawn from a population cohort. Observer-rated PEs were classified as persistent or transient on the basis of longitudinal assessments. Working memory was assessed using the n-back task during fMRI. Dynamic causal modeling (DCM) was used to characterize frontoparietal network configuration and voxel-based morphometry was utilized to examine gray matter. Those with persistent, but not transient, PEs performed worse on the n-back task, compared with controls, yet showed no significant differences in regional brain activation or brain structure. DCM analyses revealed greater emphasis on frontal connectivity within a frontoparietal network in those with PEs compared with controls. We propose that these findings portray an altered configuration of working memory function in the brain, potentially indicative of an adaptive response to atypical development associated with the manifestation of PEs

A functional role for the cancer disparity-linked genes, CRYβB2 and CRYβB2P1, in the promotion of breast cancer

Background: In the USA, the breast cancer mortality rate is 41% higher for African-American women than non-Hispanic White women. While numerous gene expression studies have classified biological features that vary by race and may contribute to poorer outcomes, few studies have experimentally tested these associations. CRYβB2 gene expression has drawn particular interest because of its association with overall survival and African-American ethnicity in multiple cancers. Several reports indicate that overexpression of the CRYβB2 pseudogene, CRYβB2P1, and not CRYβB2 is linked with race and poor outcome. It remains unclear whether either or both genes are linked to breast cancer outcomes. This study investigates CRYβB2 and CRYβB2P1 expression in human breast cancers and breast cancer cell line models, with the goal of elucidating the mechanistic contribution of CRYβB2 and CRYβB2P1 to racial disparities. Methods: Custom scripts for CRYβB2 or CRYβB2P1 were generated and used to identify reads that uniquely aligned to either gene. Gene expression according to race and tumor subtype were assessed using all available TCGA breast cancer RNA sequencing alignment samples (n = 1221). In addition, triple-negative breast cancer models engineered to have each gene overexpressed or knocked out were developed and evaluated by in vitro, biochemical, and in vivo assays to identify biological functions. Results: We provide evidence that CRYβB2P1 is expressed at higher levels in breast tumors compared to CRYβB2, but only CRYβB2P1 is significantly increased in African-American tumors relative to White American tumors. We show that independent of CRYβB2, CRYβB2P1 enhances tumorigenesis in vivo via promoting cell proliferation. Our data also reveal that CRYβB2P1 may function as a non-coding RNA to regulate CRYβB2 expression. A key observation is that the combined overexpression of both genes was found to suppress cell growth. CRYβB2 overexpression in triple-negative breast cancers increases invasive cellular behaviors, tumor growth, IL6 production, immune cell chemoattraction, and the expression of metastasis-associated genes. These data underscore that both CRYβB2 and CRYβB2P1 promote tumor growth, but their mechanisms for tumor promotion are likely distinct. Conclusions: Our findings provide novel data emphasizing the need to distinguish and study the biological effects of both CRYβB2 and CRYβB2P1 as both genes independently promote tumor progression. Our data demonstrate novel molecular mechanisms of two understudied, disparity-linked molecules

A User‐Friendly Workbook to Facilitate Rapid and Accurate Rare Earth Element Analyses by ICP‐MS for Multispiked Samples

The rare earth elements (REEs) are widely used as geochemical tracers in the earth, planetary, and ocean sciences. Inductively coupled plasma‐mass spectrometry (ICP‐MS) has become the method of choice to analyze REE concentrations because it can rapidly measure the entire REE spectrum at the same time. This Technical Report presents a user‐friendly "REE Calculation Workbook" in Microsoft Excel to be used for calculating REE abundances in samples equilibrated with a multielement REE spike. This Workbook can be conveniently used to calculate REE concentrations in natural samples for spiked and unspiked elements measured by ICP‐MS. For the spiked elements, their concentrations are calculated using isotope dilution equations. Using these spiked elements as references, concentrations of the four mono‐isotopic REE elements, and other REE elements that are treated as mono‐isotopic elements (in our case, La and Lu), can be calculated. The REE Workbook can be easily set up for use with different REE spikes. Evaluation of our analytical quality using a quadrupole ICP‐MS on 10‐ml‐sized seawater samples shows that our analyses are comparable to high‐precision thermal ionization mass spectrometry (TIMS) studies, with much less time spent processing and analyzing, and with the added advantages of determining mono‐isotopic elements. An important result is the clear demonstration of enrichments in Gd and Er compared to neighboring elements in seawater samples. In addition, we compare and evaluate commonly used reference standards BCR‐1, Post‐Archean Australian Shale (PAAS), and North American Shale Composite (NASC)

A Novel Sparse Graphical Approach for Multimodal Brain Connectivity Inference

International audienceDespite the clear potential benefits of combining fMRI and diffusion MRI in learning the neural pathways that underlie brain functions, little methodological progress has been made in this direction. In this paper, we propose a novel multimodal integration approach based on sparse Gaussian graphical model for estimating brain connectivity. Casting functional connectivity estimation as a sparse inverse covariance learning problem, we adapt the level of sparse penalization on each connection based on its anatomical capacity for functional interactions. Functional connections with little anatomical support are thus more heavily penalized. For validation, we showed on real data collected from a cohort of 60 subjects that additionally modeling anatomical capacity significantly increases subject consistency in the detected connection patterns. Moreover, we demonstrated that incorporating a connectivity prior learned with our multimodal connectivity estimation approach improves activation detection

Developmental contexts and features of elite academy football players: Coach and player perspectives

Player profiling can reap many benefits; through reflective coach-athlete dialogue that produces a profile the athlete has a raised awareness of their own development, while the coach has an opportunity to understand the athlete's viewpoint. In this study, we explored how coaches and players perceived the development features of an elite academy footballer and the contexts in which these features are revealed, in order to develop a player profile to be used for mentoring players. Using a Delphi polling technique, coaches and players experienced a number of 'rounds' of expressing their opinions regarding player development contexts and features, ultimately reduced into a consensus. Players and coaches had differing priorities on the key contexts of player development. These contexts, when they reflect the consensus between players and coaches were heavily dominated by ability within the game and training. Personal, social, school, and lifestyle contexts featured less prominently. Although 'discipline' was frequently mentioned as an important player development feature, coaches and players disagreed on the importance of 'training'