Higginslassen5396

BACKGROUND/AIMS Alterations in Parkin (PRKN) have been described in many cancers; however, the molecular mechanism that contributes to loss of Parkin expression in colorectal cancer (CRC) remains unclear. The aim of this study was to investigate the involvement of PRKN mutation and loss of heterozygosity (LOH) in loss of Parkin expression. To understand the role of PRKN in cancer progression, we also evaluated the association of Parkin expression with clinicopathological parameters in North Indian population. MATERIALS AND METHODS We studied 219 CRC samples and their adjacent normal tissues (control) obtained from North Indian patients with CRC. The expression of Parkin was analyzed by immunohistochemistry (IHC). PRKN mutations were analyzed by single-stranded conformational polymorphism (SSCP) and sequencing. For loss of heterozygosity (LOH), we employed two intragenic, D6S305 and D6S1599, and one telomeric marker, D6S1008. RESULTS In our study, we found four novel somatic mutations, namely, C166G, K413N, R420P (exon 4), and V425E (exon 11). Both mutation in Parkin (p = 0.0014) and LOH (p = 0.0140) were significantly associated with loss of Parkin expression. Additionally, Parkin mutations were not associated with the clinicopathological parameters of the patients. Furthermore, both, LOH in Parkin and Parkin expression were significantly correlated with different clinicopathological variables (p less then 0.05). CONCLUSION Our results indicate that Parkin expression is not regulated by a single mechanism, but both mutation and LOH contribute to loss of Parkin expression. We also provide evidence of involvement of Parkin in metastasis and cancer progression. We, therefore, suggest Parkin as a potential prognostic marker and warrant further analysis in this direction.BACKGROUND/AIMS The association of Epstein-Barr virus (EBV) with gastric malignancies has been proven by many studies in the literature. However, information about EBV-associated inflammation/gastritis remains limited. The aim of this study is to establish the prevalence of latent EBV infection in patients with chronic gastritis without H. pylori infection. MATERIALS AND METHODS In this study, 119 patients with gastritis without H. pylori infection were included. Furthermore, 28 patients with H. pylori gastritis were included in the study as a control group. Chromogenic in situ hybridization (EBV-encoded RNA) and immunohistochemistry (LMP-1 antibody) were performed in all 147 cases. The prevalence of EBV and its relationship with age, sex, the affected part of the stomach, the density of inflammation, inflammatory activity, intestinal metaplasia, and atrophy were analyzed. RESULTS In this study, 14 cases showed positive immunostaining for EBV. EBV positivity was seen mostly in the lymphoid tissue (13 cases), but it was also detected at the gastric epithelium (7 cases). The mean age of the patients was 44 years, which was slightly younger than that of the EBV-negative cases (48 years). The inflammation density was higher in EBV-positive cases than the EBV-negative gastritis cases (p=0.002). Intestinal metaplasia was detected in 7% of the cases. EBV-positive cases had a higher incidence of atrophy without intestinal metaplasia (21% vs 3.8% without EBV). CONCLUSION EBV was detected in 12% of the cases with gastritis without H. pylori infection. Endoscopic follow-up may be appropriate for patients with gastritis, who have atrophy without intestinal metaplasia and are H. pylori negative but EBV positive.Research conclusions differ on the impact of periampullary diverticulum (PAD) on endoscopic retrograde cholangiopancreatography (ERCP). An up-to-date meta-analysis evaluated the role of PAD in ERCP, especially in terms of cannulation failure and early complications. A comprehensive literature search was performed. All statistical analyses were carried out with the Review Manager 5.3 software. Horizontal lines represented a 95% confidence interval (CI) and the area of each square in forest plots. Twenty-six studies including 23 826 patients with or without PAD who underwent ERCP were evaluated. PAD was associated with an increase in the overall cannulation failure rate (RR=1.46, 95% CI 1.27-1.67; p less then .00001), but in the subgroup of studies performed post-2000, PAD was irrelevant to cannulation failure (RR=1.16, 95% CI 0.96-1.41; p=0.12). In overall analyses, PAD was also associated with a high risk of ERCP-related pancreatitis (RR=1.32, 95% CI 1.10-1.59; p=0.003), perforation (RR=1.73, 95% CI 1.06-2.82; p=0.030), and bleeding (RR=1.48, 95% CI 1.13-1.93; p=0.005). The presence of PAD increased the overall cannulation failure rate, but not the rate post-2000. PAD also affected the occurrence of early pancreatitis, perforation, and bleeding.A key challenge in precise genome editing is the low efficiency of homology-directed repair (HDR). Here we describe a strategy for increasing the efficiency of HDR in cells by using a chromatin donor template instead of a naked DNA donor template. The use of chromatin, which is the natural form of DNA in the nucleus, increases the frequency of HDR-edited clones as well as homozygous editing. In addition, transfection of chromatin results in negligible cytotoxicity. These findings suggest that a chromatin donor template should be useful for a wide range of HDR applications such as the precise insertion or replacement of DNA fragments that contain the coding regions of genes. © 2020, Cruz-Becerra & Kadonaga.Synchronous neurotransmitter release is triggered by Ca2+ binding to the synaptic vesicle protein Synaptotagmin 1, while asynchronous fusion and short-term facilitation is hypothesized to be mediated by plasma membrane-localized Synaptotagmin 7 (SYT7). We generated mutations in Drosophila Syt7 to determine if it plays a conserved role as the Ca2+ sensor for these processes. Electrophysiology and quantal imaging revealed evoked release was elevated 2-fold. Syt7 mutants also had a larger pool of readily-releasable vesicles, faster recovery following stimulation, and intact facilitation. Syt1/Syt7 double mutants displayed more release than Syt1 mutants alone, indicating SYT7 does not mediate the residual asynchronous release remaining in the absence of SYT1. SYT7 localizes to an internal membrane tubular network within the peri-active zone, but does not enrich at active zones. These findings indicate the two Ca2+ sensor model of SYT1 and SYT7 mediating all phases of neurotransmitter release and facilitation is not applicable at Drosophila synapses. © 2020, Guan et al.The CLC family comprises H+-coupled exchangers and Cl- channels, and mutations causing their dysfunction lead to genetic disorders. The CLC exchangers, unlike canonical 'ping-pong' antiporters, simultaneously bind and translocate substrates through partially congruent pathways. How ions of opposite charge bypass each other while moving through a shared pathway remains unknown. Here, we use MD simulations, biochemical and electrophysiological measurements to identify two conserved phenylalanine residues that form an aromatic pathway whose dynamic rearrangements enable H+ movement outside the Cl- pore. These residues are important for H+ transport and voltage-dependent gating in the CLC exchangers. The aromatic pathway residues are evolutionarily conserved in CLC channels where their electrostatic properties and conformational flexibility determine gating. Lapatinib inhibitor We propose that Cl- and H+ move through physically distinct and evolutionarily conserved routes through the CLC channels and transporters and suggest a unifying mechanism that describes the gating mechanism of both CLC subtypes. © 2020, Leisle et al.Transient Receptor Potential Melastatin 3 (TRPM3) is a Ca2+ permeable non-selective cation channel activated by heat and chemical agonists such as pregnenolone sulfate and CIM0216. TRPM3 mutations in humans were recently reported to be associated with intellectual disability and epilepsy; the functional effects of those mutations however were not reported. Here we show that both disease-associated mutations in the human TRPM3 render the channel overactive, but likely via different mechanisms. The Val to Met substitution in the S4-S5 loop induced a larger increase in basal activity and agonist sensitivity at room temperature than the Pro to Gln substitution in the extracellular segment of S6. In contrast, heat activation was increased more by the S6 mutant than by the S4-S5 segment mutant. Both mutants were inhibited by the TRPM3 antagonist primidone, suggesting a potential therapeutic intervention to treat this disease. © 2020, Zhao et al.Rett Syndrome is a devastating neurodevelopmental disorder resulting from mutations in the gene MECP2. Mutations of Mecp2 that are restricted to GABAergic cell types largely replicate the behavioral phenotypes associated with mouse models of Rett Syndrome, suggesting a pathophysiological role for inhibitory interneurons. Recent work has suggested that vasoactive intestinal peptide-expressing (VIP) interneurons may play a critical role in the proper development and function of cortical circuits, making them a potential key point of vulnerability in neurodevelopmental disorders. However, little is known about the role of VIP interneurons in Rett Syndrome. Here we find that loss of MeCP2 specifically from VIP interneurons replicates key neural and behavioral phenotypes observed following global Mecp2 loss of function. © 2020, Mossner et al.Although the cerebellum is traditionally associated with balance and motor function, it also plays wider roles in affective and cognitive behaviors. Evidence suggests that the cerebellar vermis may regulate aggressive behavior, though the cerebellar circuits and patterns of activity that influence aggression remain unclear. We used optogenetic methods to bidirectionally modulate the activity of spatially-delineated cerebellar Purkinje cells to evaluate the impact on aggression in mice. Increasing Purkinje cell activity in the vermis significantly reduced the frequency of attacks in a resident-intruder assay. Reduced aggression was not a consequence of impaired motor function, because optogenetic stimulation did not alter motor performance. In complementary experiments, optogenetic inhibition of Purkinje cells in the vermis increased the frequency of attacks. These results suggest Purkinje cell activity in the cerebellar vermis regulates aggression, and further support the importance of the cerebellum in driving affective behaviors that could contribute to neurological disorders. © 2020, Jackman et al.From the northernmost tip of Scandinavia to the southernmost corner of Patagonia, and across six continents, house sparrows (Passer domesticus) inhabit most human-modified habitats of the globe. With over 7,000 articles published, the species has become a workhorse for not only the study of self-urbanized wildlife, but also for understanding life history and body size evolution, sexual selection and many other biological phenomena. Traditionally, house sparrows were studied for their adaptations to local biotic and climatic conditions, but more recently, the species has come to serve as a focus for studies seeking to reveal the genomic, epigenetic and physiological underpinnings of success among invasive vertebrate species. Here, we review the natural history of house sparrows, highlight what the study of these birds has meant to bioscience generally, and describe the many resources available for future work on this species. © 2020, Hanson et al.