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Found 37769 matches. Displaying 2621-2630
Butelman ER, Chen CY, Brown KG, Kreek MJ
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Escalation of drug use in persons dually diagnosed with opioid and cocaine dependence: Gender comparison and dimensional predictors

DRUG AND ALCOHOL DEPENDENCE 2019 DEC 1; 205(?):? Article UNSP 107657
Background: Persons dually diagnosed with opioid and cocaine dependence (OD + CD) present a clinical challenge and are at risk of morbidity and mortality. The time of escalation of heroin and cocaine exposure in persons with OD + CD remain understudied, and the influence of gender and other variables have not been examined. This observational study focused on the time of escalation of heroin and cocaine in volunteers with OD + CD, examining gender and exposure to other drugs (e.g., cannabis or alcohol) as predictors. Ages of first use and of onset of heaviest use of each drug were collected (in whole years). Time of escalation was defined as the interval between age of first use and onset of heaviest use. Volunteers: sequentially ascertained adult volunteers recruited from the New York Metropolitan area, of which n = 297 were diagnosed with OD + CD. Methods: Instruments administered were the SCID-I diagnostic interview (DSM-IV criteria), BIS-11 impulsiveness scale, and KMSK scales, dimensional measures of maximal exposure to specific drugs. Results: In volunteers with OD + CD, ages of onset of heaviest use of cannabis (median age = 15) and alcohol (median age = 19) were in adolescence or emerging adulthood and preceded those for heroin and cocaine (median ages = 26 and 25, respectively). Maximal levels of cannabis and alcohol exposure were high, in volunteers with OD + CD. In adjusted Cox regressions, gender was not a significant predictor of time of heroin or cocaine escalation. However, more rapid time of alcohol escalation was a predictor of more rapid time of escalation of both heroin and cocaine, in volunteers with OD + CD.
We study the spatial and temporal variation of the human population in the United States (US) counties from 1790 to 2010, using an ecological scaling pattern called Taylor's law (TL). TL states that the variance of population abundance is a power function of the mean population abundance. Despite extensive studies of TL for non-human populations, testing and interpreting TL using data on human populations are rare. Here we examine three types of TL that quantify the spatial and temporal variation of US county population abundance. Our results show that TL and its quadratic extension describe the mean-variance relationship of county population distribution well. The slope and statistics of TL reveal economic and demographic trends of the county populations. We propose TL as a useful statistical tool for analyzing human population variability. We suggest new ways of using TL to select and make population projections.
Tao X, MacKinnon R
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Molecular structures of the human Slo1 K+ channel in complex with beta 4

ELIFE 2019 DEC 9; 8(?):? Article e51409
Slo1 is a Ca2+- and voltage-activated K+ channel that underlies skeletal and smooth muscle contraction, audition, hormone secretion and neurotransmitter release. In mammals, Slol is regulated by auxiliary proteins that confer tissue-specific gating and pharmacological properties. This study presents cryo-EM structures of Slo1 in complex with the auxiliary protein, beta 4. Four beta 4, each containing two transmembrane helices, encircle Slot, contacting it through helical interactions inside the membrane. On the extracellular side, beta 4 forms a tetrameric crown over the pore. Structures with high and low Ca(2+ )concentrations show that identical gating conformations occur in the absence and presence of beta 4, implying that beta 4 serves to modulate the relative stabilities of 'pre-existing' conformations rather than creating new ones. The effects of beta 4 on scorpion toxin inhibition kinetics are explained by the crown, which constrains access but does not prevent binding.
Kueck T, Bloyet LM, Cassella E, Zang T, Schmidt F, Brusic V, Tekes G, Pornillos O, Whelan SPJ, Bieniasz PD
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Vesicular Stomatitis Virus Transcription Is Inhibited by TRIM69 in the Interferon-Induced Antiviral State

JOURNAL OF VIROLOGY 2019 DEC; 93(24):? Article e01372-19
Interferons (IFNs) induce the expression of interferon-stimulated genes (ISGs), many of which are responsible for the cellular antiviral state in which the replication of numerous viruses is blocked. How the majority of individual ISGs inhibit the replication of particular viruses is unknown. We conducted a loss-of-function screen to identify genes required for the activity of alpha interferon (IFN-alpha) against vesicular stomatitis virus, Indiana serotype (VSVIND), a prototype negative-strand RNA virus. Our screen revealed that TRIM69, a member of the tripartite motif (TRIM) family of proteins, is a VSVIND inhibitor. TRIM69 potently inhibited VSVIND replication through a previously undescribed transcriptional inhibition mechanism. Specifically, TRIM69 physically associates with the VSVIND phosphoprotein (P), requiring a specific peptide target sequence encoded therein. P is a cofactor for the viral polymerase and is required for viral RNA synthesis, as well as the assembly of replication compartments. By targeting P, TRIM69 inhibits pioneer transcription of the incoming virion-associated minus-strand RNA, thereby preventing the synthesis of viral mRNAs, and consequently impedes all downstream events in the VSVIND replication cycle. Unlike some TRIM proteins, TRIM69 does not inhibit viral replication by inducing degradation of target viral proteins. Rather, higher-order TRIM69 multimerization is required for its antiviral activity, suggesting that TRIM69 functions by sequestration or anatomical disruption of the viral machinery required for VSVIND RNA synthesis. IMPORTANCE Interferons are important antiviral cytokines that work by inducing hundreds of host genes whose products inhibit the replication of many viruses. While the antiviral activity of interferon has long been known, the identities and mechanisms of action of most interferon-induced antiviral proteins remain to be discovered. We identified gene products that are important for the antiviral activity of interferon against vesicular stomatitis virus (VSV), a model virus that whose genome consists of a single RNA molecule with negative-sense polarity. We found that a particular antiviral protein, TRIM69, functions by a previously undescribed molecular mechanism. Specifically, TRIM69 interacts with and inhibits the function of a particular phosphoprotein (P) component of the viral transcription machinery, preventing the synthesis of viral messenger RNAs.
Chen J, Gopalkrishnan S, Chiu C, Chen AY, Campbell EA, Gourse RL, Ross W, Darst SA
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E. coli TraR allosterically regulates transcription initiation by altering RNA polymerase conformation

ELIFE 2019 DEC 16; 8(?):? Article e49375
TraR and its homolog DksA are bacterial proteins that regulate transcription initiation by binding directly to RNA polymerase (RNAP) rather than to promoter DNA. Effects of TraR mimic the combined effects of DksA and its cofactor ppGpp, but the structural basis for regulation by these factors remains unclear. Here, we use cryo-electron microscopy to determine structures of Escherichia coli RNAP, with or without TraR, and of an RNAP-promoter complex. TraR binding induced RNAP conformational changes not seen in previous crystallographic analyses, and a quantitative analysis revealed TraR-induced changes in RNAP conformational heterogeneity. These changes involve mobile regions of RNAP affecting promoter DNA interactions, including the Globe, the clamp, the bridge helix, and several lineage-specific insertions. Using mutational approaches, we show that these structural changes, as well as effects on sigma(70) region 1.1, are critical for transcription activation or inhibition, depending on the kinetic features of regulated promoters.
Storace A, Daniels S, Zhou Y, Kalisch B, Parker L, Rock E, Limebeer C, Lapointe T, Leri F
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A study of limbic brain derived neurotrophic factor gene expression in male Sprague-Dawley rats trained on a learned helplessness task

BEHAVIOURAL BRAIN RESEARCH 2019 DEC 30; 376(?):? Article 112174
Background: Brain derived neurotrophic factor (BDNF) has been linked to the etiology and pathology of Major Depressive Disorder (MDD). Here, the relationship between learned helplessness (LH), a cognitive/motivational state relevant to MDD, and BDNF mRNA in various limbic regions, was investigated. Methods: In Sprague-Dawley male rats, LH was induced by escape training, using a triadic design of stressor controllability involving exposure to no shocks (NS), escapable shocks (ES) or yoked inescapable shocks (IES). LH was subsequently assessed in an active avoidance task, and levels of BDNF mRNA in limbic brain regions were compared across the triad following testing. Results: Although the IES group displayed greater LH, BDNF mRNA levels were lower in the hippocampus and higher in the nucleus accumbens of both IES and ES groups. In contrast, BDNF mRNA in the basolateral amygdala was elevated only in rats exposed to IES. Conclusion: These results suggest that the inability to control an aversive stimulus can lead to a LH behavioural phenotype that is associated with region-specific alterations of BDNF gene expression in limbic nuclei.
Kampf LL, Schneider R, Gerstner L, Thunauer R, Chen MM, Helmstadter M, Amar A, Onuchic-Whitford AC, Munarriz RL, Berdeli A, Muller D, Schrezenmeier E, Budde K, Mane S, Laricchia KM, Rehm HL, MacArthur DG, Lifton RP, Walz G, Romer W, Bergmann C, Hildebrandt F, Hermle T
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TBC1D8B Mutations Implicate RAB11-Dependent Vesicular Trafficking in the Pathogenesis of Nephrotic Syndrome

JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY 2019 DEC; 30(12):2338-2353
Background Mutations in about 50 genes have been identified as monogenic causes of nephrotic syndrome, a frequent cause of CKD. These genes delineated the pathogenetic pathways and rendered significant insight into podocyte biology. Methods We used whole-exome sequencing to identify novel monogenic causes of steroid-resistant nephrotic syndrome (SRNS). We analyzed the functional significance of an SRNS-associated gene in vitro and in podocyte-like Drosophila nephrocytes. Results We identified hemizygous missense mutations in the gene TBC1D8B in five families with nephrotic syndrome. Coimmunoprecipitation assays indicated interactions between TBC1D8B and active forms of RAB11. Silencing TBC1D8B in HEK293T cells increased basal autophagy and exocytosis, two cellular functions that are independently regulated by RAB11. This suggests that TBC1D8B plays a regulatory role by inhibiting endogenous RAB11. Coimmunoprecipitation assays showed TBC1D8B also interacts with the slit diaphragm protein nephrin, and colocalizes with it in immortalized cell lines. Overexpressed murine Tbc1d8b with patient-derived mutations had lower affinity for endogenous RAB11 and nephrin compared with wild-type Tbc1d8b protein. Knockdown of Tbc1d8b in Drosophila impaired function of the podocyte-like nephrocytes, and caused mistrafficking of Sns, the Drosophila ortholog of nephrin. Expression of Rab11 RNAi in nephrocytes entailed defective delivery of slit diaphragm protein to the membrane, whereas RAB11 overexpression revealed a partial phenotypic overlap to Tbc1d8b loss of function. Conclusions Novel mutations in TBC1D8B are monogenic causes of SRNS. This gene inhibits RAB11. Our findings suggest that RAB11-dependent vesicular nephrin trafficking plays a role in the pathogenesis of nephrotic syndrome.
Woolston C, Ellis S
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ACADEMIA OR BUST

NATURE 2019 DEC 19; 576(7787):501-501
Piccolo FM, Liu Z, Dong P, Hsu CL, Stoyanova EI, Rao A, Tjian R, Heintz N
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MeCP2 nuclear dynamics in live neurons results from low and high affinity chromatin interactions

ELIFE 2019 DEC 23; 8(?):? Article e51449
Methyl-CpG-binding-Protein 2 (MeCP2) is an abundant nuclear protein highly enriched in neurons. Here we report live-cell single-molecule imaging studies of the kinetic features of mouse MeCP2 at high spatial-temporal resolution. MeCP2 displays dynamic features that are distinct from both highly mobile transcription factors and immobile histones. Stable binding of MeCP2 in living neurons requires its methyl-binding domain and is sensitive to DNA modification levels. Diffusion of unbound MeCP2 is strongly constrained by weak, transient interactions mediated primarily by its AT-hook domains, and varies with the level of chromatin compaction and cell type. These findings extend previous studies of the role of the MeCP2 MBD in high affinity DNA binding to living neurons, and identify a new role for its AT-hooks domains as critical determinants of its kinetic behavior. They suggest that limited nuclear diffusion of MeCP2 in live neurons contributes to its local impact on chromatin structure and gene expression.
Guttman-Yassky E, Diaz A, Pavel AB, Fernandes M, Lefferdink R, Erickson T, Canter T, Rangel S, Peng XY, Li R, Estrada Y, Xu H, Krueger JG, Paller AS
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Use of Tape Strips to Detect Immune and Barrier Abnormalities in the Skin of Children With Early-Onset Atopic Dermatitis

JAMA DERMATOLOGY 2019 DEC; 155(12):1358-1370
Question Can tape strips serve as a minimally invasive approach to assess biomarkers for early-onset pediatric atopic dermatitis? Findings In this cross-sectional study of 51 children younger than 5 years with and without atopic dermatitis, the use of tape strips, a minimally invasive approach for skin sampling, detected the cutaneous immune and barrier abnormalities of early-onset atopic dermatitis in infants and young children and defined biomarkers that are associated with disease severity, pruritus, and transepidermal water loss. Meaning Minimally invasive tape strips can be used to broadly characterize immune and epidermal barrier biomarkers of the lesional and nonlesional skin of children with early-onset pediatric atopic dermatitis, providing a useful, noninvasive approach for pediatric clinical trials and longitudinal studies. Importance Molecular profiling of skin biopsies is the criterion standard for evaluating the cutaneous atopic dermatitis (AD) phenotype. However, skin biopsies are not always feasible in children. A reproducible minimally invasive approach that can track cutaneous disease in pediatric longitudinal studies or clinical trials is lacking. Objective To assess a minimally invasive approach using tape strips to identify skin biomarkers that may serve as a surrogate to biomarkers identified using whole-tissue biopsies. Design, Setting, and Participants This cross-sectional study of 51 children younger than 5 years recruited children with moderate to severe AD and children without AD from the dermatology outpatient clinics at a children's hospital. Sixteen tape strips were serially collected from the nonlesional and lesional skin of 21 children who had AD and were less than 6 months from disease initiation and from the normal skin of 30 children who did not have AD between January 22, 2016, and April 20, 2018. Main Outcomes and Measures Gene and protein expression were evaluated using quantitative real-time polymerase chain reaction and immunohistochemistry. Results A total of 51 children younger than 5 years were included in the study; 21 children had moderate to severe AD with less than 6 months of disease duration, and 30 children did not have AD. Of the 21 children with AD, the mean (SD) age was 1.7 (1.7) years, and most were male (15 [71.4%] and white (15 [71.4%]). Of the 30 children without AD, the mean (SD) age was 1.8 (2.0) years, and most were female (20 [66.7%]) and white (22 [73.3%]). Seventy-seven of 79 evaluated immune and barrier gene products were detected (gene detection rate, 97%) in 70 of 71 tape strips (sample detection rate, 99%), with 53 of 79 markers differentiating between children with lesional and/or nonlesional AD from children without AD. Many cellular markers of T cells (CD3), AD-related dendritic cells (Fc epsilon RI and OX40 ligand receptors), and key inflammatory (matrix metallopeptidase 12), innate (interleukin 8 [IL-8] and IL-6), helper T cell 2 (T(H)2; IL-4, IL-13, and chemokines CCL17 and CCL26), and T(H)17/T(H)22 (IL-19, IL-36G, and S100A proteins) genes were significantly increased in lesional and nonlesional AD compared with tape strips from normal skin. For example, IL-4 mean (SE) for lesional was -15.2 (0.91) and normal was -19.5 (0.48); P < .001. Parallel decreases occurred in epidermal barrier gene products (FLG, CLDN23, and FA2H) and negative immune regulators (IL-34 and IL-37). For example, the decrease for FLG lesional was mean (SE) -2.9 (0.42) and for normal was 2.2 (0.45); P < .001. Associations were found between disease severity or transepidermal water loss and T(H)2 (IL-33 and IL-4R) and T(H)17/T(H)22 (IL-36G and S100As) products in lesional and nonlesional AD skin (evaluated using the SCORing Atopic Dermatitis, Eczema Area and Severity Index, and Pruritus Atopic Dermatitis Quickscore tools). Conclusions and Relevance In this study, tape strips provide a minimally invasive alternative for serially evaluating AD-associated cutaneous biomarkers and may prove useful for tracking pediatric AD therapeutic response and predicting future course and comorbidities. This cross-sectional study examines whether tape strips might be used to detect immune and barrier abnormalities and to define biomarkers associated with atopic dermatitis in children younger than 5 years with early-onset atopic dermatitis