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MedRxiv : the Preprint Server For... May 2024Opioid use disorders cause major morbidity and mortality, and there is a pressing need for novel mechanistic targets and biomarkers for diagnosis and prognosis. Exposure...
Opioid use disorders cause major morbidity and mortality, and there is a pressing need for novel mechanistic targets and biomarkers for diagnosis and prognosis. Exposure to mu-opioid receptor (MOR) agonists causes changes in cytokine and inflammatory protein networks in peripheral blood, and also in brain glia and neurons. Individuals with heroin use disorder (iHUD) show dysregulated levels of several cytokines in blood. However, there is limited data on a comprehensive panel of such markers in iHUD versus healthy controls (HC), especially as a multi-target biomarker. We used a validated proximity extension assay for relative quantification of 92 cytokines and inflammatory proteins in serum of iHUD on medication assisted therapy (MAT; n=21), versus HC (n=24). Twenty-nine targets showed significant group differences (primarily iHUD>HC), surviving multiple comparison correction (p=0.05). This included 19 members of canonical cytokine families, including specific chemokines, interleukins, growth factors, and tumor necrosis factor (TNF)-related proteins. For dimensionality reduction, data from these 19 cytokines were entered into a principal component (PC) analysis, and PC1 scores were iHUD>HC (p<0.0001). A receiver-operating characteristic (ROC) curve analysis yielded an AUROC=91.7% (p<0.0001). This PC1 score remained a positive predictor of being in the HUD group in a multivariable logistic regression, which included demographic/clinical variables. Overall, this study shows a panel of cytokines that differ significantly between iHUD and HC, and provides a multi-target "cytokine biomarker score" for potential diagnostic purposes, and examination of disease severity.
PubMed: 38746340
DOI: 10.1101/2024.04.29.24306559 -
BioRxiv : the Preprint Server For... Apr 2024Persistent pain affects one in five people worldwide, often with severely debilitating consequences. Current treatment options, which can be effective for mild or acute...
UNLABELLED
Persistent pain affects one in five people worldwide, often with severely debilitating consequences. Current treatment options, which can be effective for mild or acute pain, are ill-suited for moderate-to-severe persistent pain, resulting in an urgent need for new therapeutics. In recent years, the somatostatin receptor 4 (SSTR ), which is expressed in sensory neurons of the peripheral nervous system, has emerged as a promising target for pain relief. However, the presence of several closely related receptors with similar ligand-binding surfaces complicates the design of receptor-specific agonists. In this study, we report the discovery of a potent and selective SSTR peptide, consomatin Fj1, derived from extensive venom gene datasets from marine cone snails. Consomatin Fj1 is a mimetic of the endogenous hormone somatostatin and contains a minimized binding motif that provides stability and drives peptide selectivity. Peripheral administration of synthetic consomatin Fj1 provided analgesia in mouse models of postoperative and neuropathic pain. Using structure-activity studies, we designed and functionally evaluated several Fj1 analogs, resulting in compounds with improved potency and selectivity. Our findings present a novel avenue for addressing persistent pain through the design of venom-inspired SSTR -selective pain therapeutics.
ONE SENTENCE SUMMARY
Venom peptides from predatory marine mollusks provide new leads for treating peripheral pain conditions through a non-opioid target.
PubMed: 38746149
DOI: 10.1101/2024.04.29.591104 -
BioRxiv : the Preprint Server For... May 2024Mild traumatic brain injury (mTBI) increases the risk of cognitive deficits, affective disorders, anxiety and substance use disorder in affected individuals. Substantial...
Mild traumatic brain injury (mTBI) increases the risk of cognitive deficits, affective disorders, anxiety and substance use disorder in affected individuals. Substantial evidence suggests a critical role for the lateral habenula (LHb) in pathophysiology of psychiatric disorders. Recently, we demonstrated a causal link between persistent mTBI-induced LHb hyperactivity due to synaptic excitation/inhibition (E/I) imbalance and motivational deficits in self-care grooming behavior in young adult male mice using a repetitive closed head injury mTBI model. One of the major neuromodulatory systems that is responsive to traumatic brain and spinal cord injuries, influences affective states and also modulates LHb activity is the dynorphin/kappa opioid receptor (Dyn/KOR) system. However, the effects of mTBI on KOR neuromodulation of LHb function is unknown. To address this, we first used retrograde tracing to anatomically verify that the mouse LHb indeed receives Dyn/KOR expressing projections. We identified several major KOR-expressing and Dyn-expressing synaptic inputs projecting to the mouse LHb. We then functionally evaluated the effects of KOR modulation of spontaneous synaptic activity within the LHb of male and female sham and mTBI mice at 4week post-injury using the repetitive closed head injury mTBI model. Similar to what we previously reported in the LHb of male mTBI mice, mTBI presynaptically diminished spontaneous synaptic activity onto LHb neurons, while shifting synaptic E/I toward excitation in female mouse LHb. Furthermore, KOR activation in either mouse male/female LHb generally suppressed spontaneous glutamatergic transmission without altering GABAergic transmission, resulting in a significant reduction in E/I ratios and decreased excitatory synaptic drive to LHb neurons of male and female sham mice. Interestingly following mTBI, while responses to KOR activation at LHb glutamatergic synapses were observed comparable to those of sham, LHb GABAergic synapses acquired an additional sensitivity to KOR-mediated inhibition. Thus, in contrast to sham LHb, we observed a reduction in GABA release probability in response to KOR stimulation in mTBI LHb, resulting in a chronic loss of KOR-mediated net synaptic inhibition within the LHb. Overall, our findings uncovered the previously unknown sources of major Dyn/KOR-expressing synaptic inputs projecting to the mouse LHb. Further, we demonstrate that an engagement of intra-LHb Dyn/KOR signaling provides a global suppression of excitatory synaptic drive to the mouse LHb which could act as an inhibitory braking mechanism to prevent LHb hyperexcitability. The additional engagement of KOR-mediated modulatory action on LHb GABAergic transmission by mTBI could contribute to the E/I imbalance after mTBI, with Dyn/KOR signaling serving as a disinhibitory mechanism for LHb neurons in male and female mTBI mice.
PubMed: 38746139
DOI: 10.1101/2024.05.01.592017 -
BioRxiv : the Preprint Server For... Apr 2024The anterior cingulate cortex plays a pivotal role in the cognitive and affective aspects of pain perception. Both endogenous and exogenous opioid signaling within the...
The anterior cingulate cortex plays a pivotal role in the cognitive and affective aspects of pain perception. Both endogenous and exogenous opioid signaling within the cingulate mitigate cortical nociception, reducing pain unpleasantness. However, the specific functional and molecular identities of cells mediating opioid analgesia in the cingulate remain elusive. Given the complexity of pain as a sensory and emotional experience, and the richness of ethological pain-related behaviors, we developed a standardized, deep-learning platform for deconstructing the behavior dynamics associated with the affective component of pain in mice-LUPE (Light aUtomated Pain Evaluator). LUPE removes human bias in behavior quantification and accelerated analysis from weeks to hours, which we leveraged to discover that morphine altered attentional and motivational pain behaviors akin to affective analgesia in humans. Through activity-dependent genetics and single-nuclei RNA sequencing, we identified specific ensembles of nociceptive cingulate neuron-types expressing mu-opioid receptors. Tuning receptor expression in these cells bidirectionally modulated morphine analgesia. Moreover, we employed a synthetic opioid receptor promoter-driven approach for cell-type specific optical and chemical genetic viral therapies to mimic morphine's pain-relieving effects in the cingulate, without reinforcement. This approach offers a novel strategy for precision pain management by targeting a key nociceptive cortical circuit with on-demand, non-addictive, and effective analgesia.
PubMed: 38746090
DOI: 10.1101/2024.04.26.591113 -
Nature Communications May 2024G-protein-coupled receptors (GPCRs) play pivotal roles in various physiological processes. These receptors are activated to different extents by diverse orthosteric...
G-protein-coupled receptors (GPCRs) play pivotal roles in various physiological processes. These receptors are activated to different extents by diverse orthosteric ligands and allosteric modulators. However, the mechanisms underlying these variations in signaling activity by allosteric modulators remain largely elusive. Here, we determine the three-dimensional structure of the μ-opioid receptor (MOR), a class A GPCR, in complex with the G protein and an allosteric modulator, BMS-986122, using cryogenic electron microscopy. Our results reveal that BMS-986122 binding induces changes in the map densities corresponding to R167 and Y254, key residues in the structural motifs conserved among class A GPCRs. Nuclear magnetic resonance analyses of MOR in the absence of the G protein reveal that BMS-986122 binding enhances the formation of the interaction between R167 and Y254, thus stabilizing the fully-activated conformation, where the intracellular half of TM6 is outward-shifted to allow for interaction with the G protein. These findings illuminate that allosteric modulators like BMS-986122 can potentiate receptor activation through alterations in the conformational dynamics in the core region of GPCRs. Together, our results demonstrate the regulatory mechanisms of GPCRs, providing insights into the rational development of therapeutics targeting GPCRs.
Topics: Receptors, Opioid, mu; Allosteric Regulation; Humans; Cryoelectron Microscopy; Protein Binding; GTP-Binding Protein alpha Subunits, Gi-Go; HEK293 Cells; Ligands; Models, Molecular; Protein Conformation
PubMed: 38740791
DOI: 10.1038/s41467-024-47792-6 -
Annals of Medicine Dec 2024Opioids are the most prescribed drugs for the alleviation of pain. Both clinical and preclinical studies have reported strong evidence for sex-related divergence... (Review)
Review
Opioids are the most prescribed drugs for the alleviation of pain. Both clinical and preclinical studies have reported strong evidence for sex-related divergence regarding opioid analgesia. There is an increasing amount of evidence indicating that gonadal hormones regulate the analgesic efficacy of opioids. This review presents an overview of the importance of gonadal steroids in modulating opioid analgesic responsiveness and focuses on elaborating what is currently known regarding the underlyingmechanism. We sought to identify the link between gonadal hormones and the effect of oipiod antinociception.
Topics: Analgesics, Opioid; Humans; Animals; Gonadal Hormones; Male; Pain; Female
PubMed: 38738380
DOI: 10.1080/07853890.2024.2329259 -
Molecules (Basel, Switzerland) Apr 2024The synthesis of stereochemically pure oximes, amines, saturated and unsaturated cyanomethyl compounds, and methylaminomethyl compounds at the C9 position in...
The synthesis of stereochemically pure oximes, amines, saturated and unsaturated cyanomethyl compounds, and methylaminomethyl compounds at the C9 position in 3-hydroxy--phenethyl-5-phenylmorphans provided μ-opioid receptor (MOR) agonists with varied efficacy and potency. One of the most interesting compounds, (2-((1,5,9)-5-(3-hydroxyphenyl)-2-phenethyl-2-azabicyclo[3.3.1]nonan-9-yl)acetonitrile), was found to be a potent partial MOR agonist (EC = 2.5 nM, %E = 89.6%), as determined in the forskolin-induced cAMP accumulation assay. Others ranged in potency and efficacy at the MOR, from nanomolar potency with a C9 cyanomethyl compound (EC = 0.85 nM) to its totally inactive diastereomer, and three compounds exhibited weak MOR antagonist activity (the primary amine , the secondary amine , and the cyanomethyl compound ). Many of the compounds were fully efficacious; their efficacy and potency were affected by both the stereochemistry of the molecule and the specific C9 substituent. Most of the MOR agonists were selective in their receptor interactions, and only a few had δ-opioid receptor (DOR) or κ-opioid receptor (KOR) agonist activity. Only one compound, a C9-methylaminomethyl-substituted phenylmorphan, was moderately potent and fully efficacious as a KOR agonist (KOR EC = 18 nM (% E = 103%)).
Topics: Oximes; Stereoisomerism; Structure-Activity Relationship; Amines; Receptors, Opioid, mu; Humans; Animals; Molecular Structure; CHO Cells; Morphinans
PubMed: 38731416
DOI: 10.3390/molecules29091926 -
Frontiers in Cell and Developmental... 2024Acute lymphoblastic leukemia (ALL) is a hematologic cancer that mostly affects children. It accounts for over a quarter of ALL pediatric cancers, causing most of the...
Acute lymphoblastic leukemia (ALL) is a hematologic cancer that mostly affects children. It accounts for over a quarter of ALL pediatric cancers, causing most of the cancer death among children. Previously, we demonstrated that D,L-methadone causes ALL cell apoptosis via μ-opioid receptor 1 (OPRM1)-triggered ER Ca release and decrease in Ca efflux, elevating [Ca]. However, the precise mechanism by which D,L-methadone induces ER Ca release remains to be defined. Here, we show that in ALL cells, D,L-methadone-induced ER Ca release is blocked by inhibition of G, but not G, indicating that the process is dependent on G. Activation of adenylyl cyclase (AC) with forskolin or treatment with 8-CPT-cAMP blocks D,L-methadone-induced ER Ca release, indicating that the latter results from G-dependent downregulation of AC and cAMP. The 14-22 amide (myr) PKA inhibitor alone elicits ER Ca release, and subsequent treatment with D,L-methadone does not cause additional ER Ca release, indicating that PKA inhibition is a key step in D,L-methadone-induced ER Ca release and can bypass the D,L-methadone-OPRM1-AC-cAMP step. This is consistent with the decrease in PKA-dependent (i) inhibitory PLCβ3 Ser1105 phosphorylation that leads to PLCβ3 activation and ER Ca release, and (ii) BAD Ser118 phosphorylation, which together ultimately result in caspase activation and apoptosis. Thus, our findings indicate that D,L-methadone-induced ER Ca release and subsequent apoptosis in ALL cells is mediated by G-dependent downregulation of the AC-cAMP-PKA-PLCβ3/BAD pathway. The fact that 14-22 amide (myr) alone effectively kills ALL cells suggests that PKA may be targeted for ALL therapy.
PubMed: 38721527
DOI: 10.3389/fcell.2024.1388745 -
BioRxiv : the Preprint Server For... Apr 2024The lateral septum (LS) is a midline, subcortical structure, which regulates social behaviors that are frequently impaired in neurodevelopmental disorders including...
The lateral septum (LS) is a midline, subcortical structure, which regulates social behaviors that are frequently impaired in neurodevelopmental disorders including schizophrenia and autism spectrum disorder. Mouse studies have identified neuronal populations within the LS that express a variety of molecular markers, including vasopressin receptor, oxytocin receptor, and corticotropin releasing hormone receptor, that control specific facets of social behavior. Despite its critical role in the regulation of social behavior and notable gene expression patterns, comprehensive molecular profiling of the human LS has not been performed. Here, we conducted single nucleus RNA-sequencing (snRNA-seq) to generate the first transcriptomic profiles of the human LS using postmortem human brain tissue samples from 3 neurotypical donors. Our analysis identified 4 transcriptionally distinct neuronal cell types within the human LS that are enriched for , the gene encoding Trp-related protein 4. Differential expression analysis revealed a distinct LS neuronal cell type that is enriched for , the gene encoding the μ-opioid receptor. Leveraging recently collected mouse LS snRNA-seq datasets, we also conducted a cross-species analysis. Our results demonstrate that enrichment in the LS is highly conserved between human and mouse, while which encodes FRAS1 related extracellular matrix protein 2, is enriched only in the human LS. Together, these results highlight transcriptional heterogeneity of the human LS, and identify robust marker genes for the human LS.
PubMed: 38712125
DOI: 10.1101/2024.04.22.590602 -
Psychopharmacology Jul 2024Medications are urgently needed to treat symptoms of drug withdrawal and mitigate dysphoria and psychiatric comorbidities that drive opioid abuse and relapse. ITI-333 is...
RATIONALE
Medications are urgently needed to treat symptoms of drug withdrawal and mitigate dysphoria and psychiatric comorbidities that drive opioid abuse and relapse. ITI-333 is a novel molecule in development for treatment of substance use disorders, psychiatric comorbidities, and pain.
OBJECTIVE
Characterize the preclinical profile of ITI-333 using pharmacological, behavioral, and physiological assays.
METHODS
Cell-based assays were used to measure receptor binding and intrinsic efficacy of ITI-333; animal models were employed to assess effects on opioid reinstatement, precipitated oxycodone withdrawal, and drug abuse liability.
RESULTS
In vitro, ITI-333 is a potent 5-HT receptor antagonist (K = 8 nM) and a biased, partial agonist at μ-opioid (MOP) receptors (K = 11 nM; lacking β-arrestin agonism) with lesser antagonist activity at adrenergic α (K = 28 nM) and dopamine D (K = 50 nM) receptors. In vivo, ITI-333 blocks 5-HT receptor-mediated head twitch and MOP receptor-mediated effects on motor hyperactivity in mice. ITI-333 alone is a naloxone-sensitive analgesic (mice) which suppresses somatic signs of naloxone-precipitated oxycodone withdrawal (mice) and heroin cue-induced reinstatement responding without apparent tolerance or physical dependence after chronic dosing (rats). ITI-333 did not acutely impair gastrointestinal or pulmonary function (rats) and was not intravenously self-administered by heroin-maintained rats or rhesus monkeys.
CONCLUSIONS
ITI-333 acts as a potent 5-HT receptor antagonist, as well a biased MOP receptor partial agonist with low intrinsic efficacy. ITI-333 mitigates opioid withdrawal/reinstatement, supporting its potential utility as a treatment for OUD.
Topics: Animals; Mice; Male; Substance Withdrawal Syndrome; Rats; Humans; Rats, Sprague-Dawley; Receptors, Opioid, mu; Serotonin 5-HT2 Receptor Antagonists; Substance-Related Disorders; Opioid-Related Disorders; Dose-Response Relationship, Drug; Oxycodone; Analgesics, Opioid; Self Administration; Cricetulus; CHO Cells
PubMed: 38710856
DOI: 10.1007/s00213-024-06578-w