Genome-wide analysis of dorsal root ganglion (DRG) gene expression after morphine or oxycodone treatment
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ABSTRACT: Analyse of gene expression modification after chronic analgesic treatment. The hypothesis tested in the present study was that oxycodone and morphine induced gene expression modification. Results provide important information to understand the analgesic effects of oxycodone as compared to morphine in a neuropathic pain model
Project description:Analyse of gene expression modification after chronic analgesic treatment. The hypothesis tested in the present study was that oxycodone and morphine induced gene expression modification. Results provide important information to understand the analgesic effects of oxycodone as compared to morphine in a neuropathic pain model Total RNA obtained from DRG of neuropathic or control animals after oxycodone or morphine treatment
Project description:The development of physical dependence and addiction disorders due to misuse of opioid analgesics is a major concern with pain therapeutics. In this study, we developed a mouse model of oxycodone exposure to gain insight into genes and molecular pathways in reward-related brain regions that are affected by prolonged exposure to oxycodone and subsequent withdrawal in the presence or absence of chronic neuropathic pain. RNA-Sequencing (RNA-Seq) and bioinformatic analyses revealed that oxycodone withdrawal alone triggers robust gene expression adaptations in the nucleus accumbens (NAc), medial prefrontal cortex (mPFC), and ventral tegmental area (VTA), with numerous genes and pathways selectively affected by oxycodone withdrawal under peripheral nerve injury states. Our pathway analysis predicted that histone deacetylase 1 (HDAC1), an epigenetic modifier with a prominent role in striatal plasticity, is a top upstream regulator in opioid withdrawal in both the NAc and mPFC. Indeed, treatment with the novel HDAC1/2 inhibitor RBC1HI (Regenacy Brain Class 1 HDAC Inhibitor) attenuated behavioral manifestations of oxycodone withdrawal, with the drug being more efficacious under states of neuropathic pain. Since RBC1HI displays antiallodynic actions in models of neuropathic pain, inhibition of HDAC1/2 may provide an avenue for chronic pain patients dependent on opioids to transition to non-opioid analgesics. Overall, our study highlights transcriptomic events in components of the reward circuitry associated with oxycodone withdrawal under pain-free and prolonged neuropathic pain states, thereby providing information on possible new targets for the treatment of physical dependence to opioids and transitioning individuals to non-opioid medications for chronic pain management.
Project description:Sickle cell disease is the most common genetic disorder in African-Americans. The opioid analgesic, morphine, has long been the treatment for the severe pain associated with this disease. Here we reveal that the opioid antagonist, naloxone, possesses potent analgesic activity in two strains of sickle cell mice (NY1DD and hBERK1) and not in their respective controls (ICR-CD1 and C57BL/6J) when administered by three parenteral routes. In the NY1DD sickle mice, naloxone (i.c.v.) possessed ~300-fold greater potency than morphine (i.c.v.). Other opioid antagonists (naltrexone, norbinaltorphimine, naltrindole) were substantially less effective in producing analgesia. Naloxone and morphine were synergistic in NY1DD mice, suggesting that analgesia was mediated via different receptor systems. Since microarray analysis suggested naloxone-induced down-regulation of the CCR5 chemokine receptor in NY1DD mice but not in control mice, the role of its endogenous ligand, CCL5 (RANTES), was investigated. Keywords: Comparison of drug induced gene expression
Project description:Nociceptive response belongs to a basic animal behavior facilitating adaptability and survival upon external or internal stimuli. Fish, similarly to higher vertebrates, also possess nociceptive machinery. Current protocols involving procedures performed on adult zebrafish including heart cryoinjury do not, however, take into account the adverse effects including pain that may potentially arise from these methodologies. Here, we assess the effect of two analgesics, lidocaine and morphine, followed after the heart cryoinjury in zebrafish. Monitoring swimming behaviour together with histology and gene expression analysis at the single cell level using scRNA sequencing and RNAscope fluorescent in situ hybridization technology, we show morphine, but not lidocaine, significantly improves animal welfare 6 hours post-cryoinjury, without impairing heart regeneration process. Altogether, morphine should be considered as the analgesic of choice to reduce post-surgical pain in adult zebrafish.
Project description:To investigate the involvement of Neat1 in neuropathic pain, Neat1 was knocked down in DRG neurons by the injection of AAV vector encoding shRNA for Neat1.
Project description:Our previous study showed that Dicer1 expression is positively correlated with the development of analgesic tolerance. To further understand the miRNA regulation by Dicer in the development of tolerance, we performed microRNA profiling using Agilent mouse miRNA arrays to identify the miRNA profiles in the prefrontal cortex from C57BL/6J (C57) mice under saline or morphine treatment.
Project description:Epigenetic changes are essential for normal development and ageing, but there is still limited understanding of how environmental factors can cause epigenetic changes that leads to health problems or diseases. Morphine is known to pass through the placental barrier and impact normal embryo development by affecting the neural tube, frontal cortex and spinal cord development, and, as a consequence, delaying nervous system development. In fact, in-utero morphine exposure has shown alterations in anxiety-like behaviours, analgesic tolerance, synaptic plasticity and the neuronal structure of offspring. However, how morphine leads to abnormal neurogenesis and other physiological consequences during embryo development is still unknown. Considering that DNA methylation is a key epigenetic factor crucial for embryo development, our aim is to elucidate the role of methylation in response to morphine. Chronic morphine treatment (24h, 10μM) induces a global hypomethylation in mESC. WGBSeq identifies 16,808 sensitive to morphine which are involved in embryo development, signalling pathways, metabolism and/or gene expression, suggesting that morphine might impact methylation levels at developmental genes. Integrative analyses between WGBSeq and RNASeq identified Tet1 as morphine-sensitive gene. Morphine increased the gene expression of Tet1, modifying the methylation levels at the promoter. On the other hand, RNASeq and qRT-PCR analyses revealed that Dnmt1 gene expression decreased after morphine treatment, without altering the methylation patter at its promoters. By MS/MS approaches confirms a decrease in DNA methylation after chronic morphine treatment, together with an increase in hydroxymethylation global levels in mESCs. In conclusion, morphine induces a global hypomethylation in mESC through different mechanisms that involves passive demethylation and a self-regulatory mechanism via active demethylation.
Project description:Using an oral self-administration paradigm, we have seen morphine increase neural activity in the Paraventricular Nucleus of the Thalamus (PVT). Morphine binds primarily to Mu Opioid Receptors (MORs), which are highly expressed in the PVT. Translating Ribosome Affinity Purification (TRAP)-Sequencing was conducted on PVT neurons that express MORs
Project description:Histone deacetylase inhibitors (HDACIs) interfere with the epigenetic process of histone acetylation and are known to have analgesic properties in models of chronic inflammatory pain. The aim of this study was to determine whether these compounds could also affect neuropathic pain. Different class I HDACIs were delivered intrathecally into rat spinal cord in models of traumatic nerve injury and antiretroviral drug-induced peripheral neuropathy (stavudine, d4T). Mechanical and thermal hypersensitivity was attenuated by 40% to 50% as a result of HDACI treatment, but only if started before any insult. The drugs globally increased histone acetylation in the spinal cord, but appeared to have no measurable effects in relevant dorsal root ganglia in this treatment paradigm, suggesting that any potential mechanism should be sought in the central nervous system. Microarray analysis of dorsal cord RNA revealed the signature of the specific compound used (MS-275) and suggested that its main effect was mediated through HDAC1. Taken together, these data support a role for histone acetylation in the emergence of neuropathic pain. n = 4, HDACi treated vs. vehicle treated. Injured ipsilateral DRG after L5 spinal nerve transection. Spinal cord tissue was run in a separate Affymetrix experiment.
Project description:Visium Spatial Gene Expression by the 10X genomics protocol was performed on 2 sections of human DRG tissue to elucidate the spatial transcriptomic organization.