43 research outputs found
Apontic regulates somatic stem cell numbers in Drosophila testes
BACKGROUND: Microenvironments called niches maintain resident stem cell populations by balancing self-renewal with differentiation, but the genetic regulation of this process is unclear. The niche of the Drosophila testis is well-characterized and genetically tractable, making it ideal for investigating the molecular regulation of stem cell biology. The JAK/STAT pathway, activated by signals from a niche component called the hub, maintains both germline and somatic stem cells.
RESULTS: This study investigated the molecular regulation of the JAK/STAT pathway in the stem cells of the Drosophila testis. We determined that the transcriptional regulator Apontic (Apt) acts in the somatic (cyst) stem cells (CySCs) to balance differentiation and maintenance. We found Apt functions as a negative feedback inhibitor of STAT activity, which enables cyst cell maturation. Simultaneous loss of the STAT regulators apt and Socs36E, or the Stat92E-targeting microRNA miR-279, expanded the somatic stem cell-like population.
CONCLUSIONS: Genetic analysis revealed that a conserved genetic regulatory network limits JAK/STAT activity in the somatic stem cells of Drosophila testis. In these cells, we determined JAK/STAT signaling promotes apt expression. Then, Apt functions through Socs36E and miR-279 to attenuate pathway activation, which is required for timely CySC differentiation. We propose that Apt acts as a core component of a STAT-regulatory circuit to prevent stem cell overpopulation and allow stem cell maturation
Therapeutic efficacy of anti-MMP9 antibody in combination with nab-paclitaxel-based chemotherapy in pre-clinical models of pancreatic cancer
Matrix metalloproteinase 9 (MMP9) is involved in the proteolysis of extracellular proteins and plays a critical role in pancreatic ductal adenocarcinoma (PDAC) progression, invasion and metastasis. The therapeutic potential of an anti-MMP9 antibody (αMMP9) was evaluated in combination with nab-paclitaxel (NPT)-based standard cytotoxic therapy in pre-clinical models of PDAC. Tumour progression and survival studies were performed in NOD/SCID mice. The mechanistic evaluation involved RNA-Seq, Luminex, IHC and Immunoblot analyses of tumour samples. Median animal survival compared to controls was significantly increased after 2-week therapy with NPT (59%), Gem (29%) and NPT+Gem (76%). Addition of αMMP9 antibody exhibited further extension in survival: NPT+αMMP9 (76%), Gem+αMMP9 (47%) and NPT+Gem+αMMP9 (94%). Six-week maintenance therapy revealed that median animal survival was significantly increased after NPT+Gem (186%) and further improved by the addition of αMMP9 antibody (218%). Qualitative assessment of mice exhibited that αMMP9 therapy led to a reduction in jaundice, bloody ascites and metastatic burden. Anti-MMP9 antibody increased the levels of tumour-associated IL-28 (1.5-fold) and decreased stromal markers (collagen I, αSMA) and the EMT marker vimentin. Subcutaneous tumours revealed low but detectable levels of MMP9 in all therapy groups but no difference in MMP9 expression. Anti-MMP9 antibody monotherapy resulted in more gene expression changes in the mouse stroma compared to the human tumour compartment. These findings suggest that anti-MMP9 antibody can exert specific stroma-directed effects that could be exploited in combination with currently used cytotoxics to improve clinical PDAC therapy
HLA-DQA1*05 carriage associated with development of anti-drug antibodies to infliximab and adalimumab in patients with Crohn's Disease
Anti-tumor necrosis factor (anti-TNF) therapies are the most widely used biologic drugs for treating immune-mediated diseases, but repeated administration can induce the formation of anti-drug antibodies. The ability to identify patients at increased risk for development of anti-drug antibodies would facilitate selection of therapy and use of preventative strategies.This article is freely available via Open Access. Click on Publisher URL to access the full-text
The genetic architecture of the human cerebral cortex
The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder
ReaDAPting the Role of PGRP-SD in Bacterial Sensing and Immune Activation
Contradictory to previous reports, Iatsenko et al. (2016) reveal that PGRP-SD regulates the Imd signaling pathway rather than the Toll pathway in Drosophila and shed light on a decade-old mystery of conflicting structural and phenotypic data
Enabling students to participate in school improvement through a students as researchers programme
âThe final, definitive version of this article has been published in the Journal Improving Schools, 12 (2), 2009, © SAGE Publications Ltd, 2009: on SAGE Journals Online: http://online.sagepub.com/âThis paper explores studentsâ potential to make a difference to their school through a Students as Researchers programme. It begins by discussing the impetus for the current increase in student voice initiatives in schools. It continues the debate around issues of student empowerment and studentsâ identity as change agents through an analysis of the development of a Students as Researchers (SAR) programme designed to support school improvement. The article investigates the possibilities for impact offered by a stepped approach to the student research process, early planning for impact and a strong student/teacher partnership. Issues are illuminated though reference to the authorsâ work with Students as Researchers groups in several UK schools. The article concludes with an exploration of ways of enhancing the impact of studentsâ work on the development of their schools.Peer reviewe
Unique patterns of substance misuse associated with PSTD, depression, and social phobia
This study investigated the relations between post-trauma psychopathology and substance abuse in a sample of trauma-exposed college students (N = 136) assigned to four groups based on primary diagnosis: post-traumatic stress disorder (PTSD), depression, social phobia, or well-adjusted (participants who had low levels of distress). Groups were compared on a series of dimensions of substance use/abuse. Participants in the PTSD group evidenced greater substance use and abuse than those in the social phobia and well-adjusted groups on several dimensions and greater alcohol consumption than the depressed group. Correlation analyses suggested that most dimensions of substance abuse were related more strongly to avoidance and numbing (cluster C) symptoms than to re-experiencing and hyperarousal. The present findings suggest that trauma-related psychopathology may be associated with a more hazardous pattern of substance use than depression and social phobia. Copyright © Taylor & Francis Group, LLC
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Continuous Transversus Abdominis Plane Nerve Blocks: Does Varying Local Anesthetic Delivery Method-Automatic Repeated Bolus Versus Continuous Basal Infusion-Influence the Extent of Sensation to Cold?: A Randomized, Triple-Masked, Crossover Study in Volunteers.
BackgroundIt remains unknown whether continuous or scheduled intermittent bolus local anesthetic administration is preferable for transversus abdominis plane (TAP) catheters. We therefore tested the hypothesis that when using TAP catheters, providing local anesthetic in repeated bolus doses increases the cephalad-caudad cutaneous effects compared with a basal-only infusion.MethodsBilateral TAP catheters (posterior approach) were inserted in 24 healthy volunteers followed by ropivacaine 2 mg/mL administration for a total of 6 hours. The right side was randomly assigned to either a basal infusion (8 mL/h) or bolus doses (24 mL administered every 3 hours for a total of 2 bolus doses) in a double-masked manner. The left side received the alternate treatment. The primary end point was the extent of sensory deficit as measured by cool roller along the axillary line at hour 6 (6 hours after the local anesthetic administration was initiated). Secondary end points included the extent of sensory deficit as measured by cool roller and Von Frey filaments along the axillary line and along a transverse line at the level of the anterior superior iliac spine at hours 0 to 6.ResultsAlthough there were statistically significant differences between treatments within the earlier part of the administration period, by hour 6 the difference in extent of sensory deficit to cold failed to reach statistical significance along the axillary line (mean = 0.9 cm; SD = 6.8; 95% confidence interval -2.0 to 3.8; P = .515) and transverse line (mean = 2.5 cm; SD = 10.1; 95% confidence interval -1.8 to 6.8; P = .244). Although the difference between treatments was statistically significant at various early time points for the horizontal, vertical, and estimated area measurements of both cold and mechanical pressure sensory deficits, no comparison remained statistically significant by hour 6.ConclusionsNo evidence was found in this study involving healthy volunteers to support the hypothesis that changing the local anesthetic administration technique (continuous basal versus hourly bolus) when using ropivacaine 0.2% and TAP catheters at 8 mL/h and 24 mL every 3 hours significantly influences the cutaneous effects after 6 hours of administration. Additional research is required to determine whether changing variables (eg, local anesthetic concentration, basal infusion rate, bolus dose volume, and/or interval) would provide different results