Anterograde trafficking of KCa3.1 in polarized epithelia is Rab1- And Rab8-Dependent and recycling endosome-independent

The intermediate conductance, Ca2+-activated K+ channel (KCa3.1) targets to the basolateral (BL) membrane in polarized epithelia where it plays a key role in transepithelial ion transport. However, there are no studies defining the anterograde and retrograde trafficking of KCa3.1 in polarized epithelia. Herein, we utilize Biotin Ligase Acceptor Peptide (BLAP)-tagged KCa3.1 to address these trafficking steps in polarized epithelia, using MDCK, Caco-2 and FRT cells. We demonstrate that KCa3.1 is exclusively targeted to the BL membrane in these cells when grown on filter supports. Following endocytosis, KCa3.1 degradation is prevented by inhibition of lysosomal/proteosomal pathways. Further, the ubiquitylation of KCa3.1 is increased following endocytosis from the BL membrane and PR-619, a deubiquitylase inhibitor, prevents degradation, indicating KCa3.1 is targeted for degradation by ubiquitylation. We demonstrate that KCa3.1 is targeted to the BL membrane in polarized LLC-PK1 cells which lack the m1B subunit of the AP-1 complex, indicating BL targeting of KCa3.1 is independent of μ1B. As Rabs 1, 2, 6 and 8 play roles in ER/Golgi exit and trafficking of proteins to the BL membrane, we evaluated the role of these Rabs in the trafficking of KCa3.1. In the presence of dominant negative Rab1 or Rab8, KCa3.1 cell surface expression was significantly reduced, whereas Rabs 2 and 6 had no effect. We also co-immunoprecipitated KCa3.1 with both Rab1 and Rab8. These results suggest these Rabs are necessary for the anterograde trafficking of KCa3.1. Finally, we determined whether KCa3.1 traffics directly to the BL membrane or through recycling endosomes in MDCK cells. For these studies, we used either recycling endosome ablation or dominant negative RME-1 constructs and determined that KCa3.1 is trafficked directly to the BL membrane rather than via recycling endosomes. These results are the first to describe the anterograde and retrograde trafficking of KCa3.1 in polarized epithelia cells. © 2014 Bertuccio et al

Identification of Molecular Pathologies Sufficient to Cause Neuropathic Excitability in Primary Somatosensory Afferents Using Dynamical Systems Theory

Pain caused by nerve injury (i.e. neuropathic pain) is associated with development of neuronal hyperexcitability at several points along the pain pathway. Within primary afferents, numerous injury-induced changes have been identified but it remains unclear which molecular changes are necessary and sufficient to explain cellular hyperexcitability. To investigate this, we built computational models that reproduce the switch from a normal spiking pattern characterized by a single spike at the onset of depolarization to a neuropathic one characterized by repetitive spiking throughout depolarization. Parameter changes that were sufficient to switch the spiking pattern also enabled membrane potential oscillations and bursting, suggesting that all three pathological changes are mechanistically linked. Dynamical analysis confirmed this prediction by showing that excitability changes co-develop when the nonlinear mechanism responsible for spike initiation switches from a quasi-separatrix-crossing to a subcritical Hopf bifurcation. This switch stems from biophysical changes that bias competition between oppositely directed fast- and slow-activating conductances operating at subthreshold potentials. Competition between activation and inactivation of a single conductance can be similarly biased with equivalent consequences for excitability. “Bias” can arise from a multitude of molecular changes occurring alone or in combination; in the latter case, changes can add or offset one another. Thus, our results identify pathological change in the nonlinear interaction between processes affecting spike initiation as the critical determinant of how simple injury-induced changes at the molecular level manifest complex excitability changes at the cellular level. We demonstrate that multiple distinct molecular changes are sufficient to produce neuropathic changes in excitability; however, given that nerve injury elicits numerous molecular changes that may be individually sufficient to alter spike initiation, our results argue that no single molecular change is necessary to produce neuropathic excitability. This deeper understanding of degenerate causal relationships has important implications for how we understand and treat neuropathic pain

Evolution of MicroRNA Genes in Oryza sativa and Arabidopsis thaliana: An Update of the Inverted Duplication Model

The origin and evolution of microRNA (miRNA) genes, which are of significance in tuning and buffering gene expressions in a number of critical cellular processes, have long attracted evolutionary biologists. However, genome-wide perspectives on their origins, potential mechanisms of their de novo generation and subsequent evolution remain largely unsolved in flowering plants. Here, genome-wide analyses of Oryza sativa and Arabidopsis thaliana revealed apparently divergent patterns of miRNA gene origins. A large proportion of miRNA genes in O. sativa were TE-related and MITE-related miRNAs in particular, whereas the fraction of these miRNA genes much decreased in A. thaliana. Our results show that the majority of TE-related and pseudogene-related miRNA genes have originated through inverted duplication instead of segmental or tandem duplication events. Based on the presented findings, we hypothesize and illustrate the four likely molecular mechanisms to de novo generate novel miRNA genes from TEs and pseudogenes. Our rice genome analysis demonstrates that non-MITEs and MITEs mediated inverted duplications have played different roles in de novo generating miRNA genes. It is confirmed that the previously proposed inverted duplication model may give explanations for non-MITEs mediated duplication events. However, many other miRNA genes, known from the earlier proposed model, were rather arisen from MITE transpositions into target genes to yield binding sites. We further investigated evolutionary processes spawned from de novo generated to maturely-formed miRNA genes and their regulatory systems. We found that miRNAs increase the tunability of some gene regulatory systems with low gene copy numbers. The results also suggest that gene balance effects may have largely contributed to the evolution of miRNA regulatory systems

Standards of Care for the Health of Transsexual, Transgender and Gender Nonconforming People

The World Professional Association for Transgender Health promotes the highest standards of health care for individuals through the articulation of Standards of Care (SOC) for the Health of Transsexual, Transgender, and Gender Nonconforming People. The SOC are based on the best available science and expert professional consensus. The overall goal of the SOC is to provide clinical guidance for health professionals to assist transsexual, transgender, and gender nonconforming people with safe and effective pathways to achieving lasting personal comfort with their gendered selves, in order to maximize their overall health, psychological well-being, and self-fulfillment. This assistance may include primary care, gynecologic and urologic care, reproductive options, voice and communication therapy, mental health services (e.g., assessment, counseling, psychotherapy), and hormonal and surgical treatments. While this is primarily a document for health professionals, the SOC may also be used by individuals, their families, and social institutions to understand how they can assist with promoting optimal health for members of this diverse population. This is the 7th version of the Standards of Care since the original 1979 document. The first six versions were published in 1979, 1980, 1981, 1990, 1998, and 2001. Version 7 of the Standards of Care (SOC) for the Health of Transsexual, Transgender, and Gender Nonconforming People will be available in several additional places for wide distribution and ease of access

25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

Two Babinski signs in seropositive (HAM) and seronegative tropical spastic paraparesis Dos signos de Babinski en pacientes con paraparesia espástica tropical seropositiva (HAM) y seronegativa

Tropical spastic paraparesis (TSP) may or may not be associated to HTLV-I antibodies and is usually characterized by clinical and pathological spinal cord abnormalities at thoracic levels. We present here five Brazilian patients who had typical chronic idiopatic spastic paraparesis; two of them were HTLV-I seropositive (HAM) and three HTLV-I seronegative (TSP) - associated-myelopathy. Three out of these five patients also displayed clinical supraspinal involvement, indeed, platysma muscle hypotrophy or atrophy (the Babinski plus sign). These findings support the view that clinical involvement in HAM and TSP is wider than the spinal cord abnormalities usually considered. Possible non-infectious co-factors (e.g., mycotoxins) may be involved in disease pathogenesis in a multistep process of viruses, toxins and environment which may account for serological differences found in this group of patients.<br>La paraparesia espástica tropical (PET), puede o no estar asociada con anticuerpos contra el HTLV-I y se caracteriza, usualmente, por alteraciones clínicas y patológicas a nivel de region dorso-lumbar de la medula espinal. Presentamos cinco pacientes brasileros, quienes tuvieron hallazgos típicos de paraparesia espástica crónica idiopática; dos de ellos tuvieron (HAM) y tres no tuvieron (TSP) anticuerpos, en el suero, contra el HTLV-I. En tres pacientes se encontró hipotrofia o atrofia del músculo platisma (signo de Babinski plus), demostrando que el compromiso clínico en pacientes con HAM y TSP se extiende más allá de la médula espinal torácica. Cofactores (por ejemplo, micotoxinas) podrían estar involucrados en la patogénesis de esta enfermedad, en una interacción compleja de virus, toxinas y medio ambiente, lo cual explicaría las diferencias serológicas encontradas en este grupo de pacientes