P2Y2 receptor activation regulates the expression of acetylcholinesterase and acetylcholine receptor genes at vertebrate neuromuscular junctions

ABSTRACT At the vertebrate neuromuscular junction (nmj), ATP is known to be coreleased with acetylcholine from the synaptic vesicles. We have previously shown that the P2Y 1 receptor is localized at the nmj. Here, we extend the findings to show that another nucleotide receptor, P2Y 2 , is also localized there and with P2Y 1 jointly mediates trophic responses to ATP. The P2Y 2 receptor mRNA in rat muscle increased during development and peaked in adulthood. The P2Y 2 receptor protein was shown to become restricted to the nmjs during embryonic development, in chick and in rat. In both rat and chick myotubes, P2Y 1 and P2Y 2 are expressed, increasing with differentiation, but P2Y 4 is absent. The P2Y 2 agonist UTP stimulated there inositol trisphosphate production and phosphorylation of extracellular signal-regulated kinases, in a dose-dependent manner. These UTP-induced responses were insensitive to the P2Y 1 -specific antagonist MRS 2179 (2Ј-deoxy-N 6 -methyl adenosine 3Ј,5Ј-diphosphate diammonium salt). In differentiated myotubes, P2Y 2 activation induced expression of acetylcholinesterase (AChE) protein (but not control ␣-tubulin). This was shown to arise from AChE promoter activation, mediated by activation of the transcription factor Elk-1. Two Elk-1-responsive elements, located in intron-1 of the AChE promoter, were found by mutation to act in this gene activation initiated at the P2Y 2 receptor and also in that initiated at the P2Y 1 receptor. Furthermore, the promoters of different acetylcholine receptor subunits were also stimulated by application of UTP to myotubes. These results indicate that ATP regulates postsynaptic gene expressions via a common pathway triggered by the activation of P2Y 1 and P2Y 2 receptors at the nmjs

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

ATP potentiates the formation of AChR aggregate in the co-culture of NG108-15 cells with C2C12 myotubes

AbstractThe role of adenosine 5′-triphosphate (ATP) and P2Y1 nucleotide receptor in potentiating agrin-induced acetylcholine receptor (AChR) aggregation is being demonstrated in a co-culture system of NG108-15 cell, a mouse neuroblastoma X rat glioma hybrid cell line that resembles spinal motor neuron, with C2C12 myotube. In the co-cultures, antagonized P2Y1 receptors showed a reduction in NG108-15 cell-induced AChR aggregation. Parallel to this observation, cultured NG108-15 cell secreted ATP into the conditioned medium in a time-dependent manner. Enhancement of ATP release from the cultured NG108-15 cells by overexpression of active mutants of small GTPases increased the aggregation of AChRs in co-culturing with C2C12 myotubes. In addition, ecto-nucleotidase was revealed in the co-culture, which rapidly degraded the applied ATP. These results support the notion that ATP has a role in directing the formation of post-synaptic apparatus in vertebrate neuromuscular junctions

Calcitonin gene-related peptide induces the expression of acetylcholinesterase-associated collagen ColQ in muscle: a distinction in driving two different promoters between fast- and slow-twitch muscle fibers

The presence of a collagenous protein (CoIQ) characterizes the collagen-tailed forms of acetylcholinesterase at vertebrate neuromuscular junctions (nmjs). Two ColQ transcripts as CoIQ-1 and CoIQ-1a, driven by two promoters: pCoIQ-1 and pCoIQ-1a, were found in mammalian slow- and fast-twitch muscles, respectively, which have distinct expression pattern in different muscle fibers. In this study, we show the differential expression of CoQ in different muscles is triggered by calcitonin gene-related peptide (CGRP), a known motor neuron-derived factor. Application of CGRP, or dibutyryl-cAMP (Bt(2)-cAMP), in cultured myotubes induced the expression of CoIQ-1a transcript and promoter activity; however, the expression of CoIQ-1 transcript did not respond to CGRP (Bt(2)-cAMP). The CGRP-induced gene activation was blocked by an adenylyl cyclase inhibitor or a dominant negative mutant of cAMP-responsive element (CRE) binding protein (CREB). Two CRE sites were mapped within the CoIQ-1a promoter, and mutations of the CRE sites abolished the response of CGRP or Bt(2)-cAMP. In parallel, CGRP receptor complex was dominantly expressed at the nmjs of fast muscle but not of slow muscle. These results suggested that the expression of CoIQ-1a at the nmjs of fast-twitch muscle was governed by a CGRP-mediated cAMP signaling mechanism

ATP Induces Synaptic Gene Expressions in Cortical Neurons: Transduction and Transcription Control via P2Y1 ReceptorsS⃞

Studies in vertebrate neuromuscular synapses have revealed previously that ATP, via P2Y receptors, plays a critical role in regulating postsynaptic gene expressions. An equivalent regulatory role of ATP and its P2Y receptors would not necessarily be expected for the very different situation of the brain synapses, but we provide evidence here for a brain version of that role. In cultured cortical neurons, the expression of P2Y1 receptors increased sharply during neuronal differentiation. Those receptors were found mainly colocalized with the postsynaptic scaffold postsynaptic density protein 95 (PSD-95). This arises through a direct interaction of a PDZ domain of PSD-95 with the C-terminal PDZ-binding motif, D-T-S-L of the P2Y1 receptor, confirmed by the full suppression of the colocalization upon mutation of two amino acids therein. This interaction is effective in recruiting PSD-95 to the membrane. Specific activation of P2Y1 (G-protein-coupled) receptors induced the elevation of intracellular Ca2+ and activation of a mitogen-activated protein kinase/Raf-1 signaling cascade. This led to distinct up-regulation of the genes encoding acetylcholinesterase (AChET variant), choline acetyltransferase, and the N-methyl-d-aspartate receptor subunit NR2A. This was confirmed, in the example of AChE, to arise from P2Y1-dependent stimulation of a human ACHE gene promoter. That involved activation of the transcription factor Elk-1; mutagenesis of the ACHE promoter revealed that Elk-1 binding at its specific responsive elements in that promoter was induced by P2Y1 receptor activation. The combined findings reveal that ATP, via its P2Y1 receptor, can act trophically in brain neurons to regulate the gene expression of direct effectors of synaptic transmission