Morphine administration induces change in anxiety-related behavior via Wnt/β-catenin signaling

Vilazodone Alleviates Neurogenesis-Induced Anxiety in the Chronic Unpredictable Mild Stress Female Rat Model: Role of Wnt/β-Catenin Signaling

Defective β-catenin signaling is accompanied with compensatory neurogenesis process that may pave to anxiety. β-Catenin has a distinct role in alleviating anxiety in adolescence; however, it undergoes degradation by the degradation complex Axin and APC. Vilazodone (VZ) is a fast, effective antidepressant with SSRI activity and 5-HT1A partial agonism that amends somatic and/or psychic symptoms of anxiety. Yet, there is no data about anxiolytic effect of VZ on anxiety-related neurogenesis provoked by stress-reduced β-catenin signaling. Furthermore, females have specific susceptibility toward psychopathology. The aim of the present study is to uncover the molecular mechanism of VZ relative to Wnt/β-catenin signaling in female rats. Stress-induced anxiety was conducted by subjecting the rats to different stressful stimuli for 21 days. On the 15th day, stressed rats were treated with VZ(10 mg/kg, p.o.) alone or concomitant with the Wnt inhibitor: XAV939 (0.1 mg/kg, i.p.). Anxious rats showed low β-catenin level turned over by Axin-1 with unanticipated reduction of APC pursued with elevated protein levels of neurogenesis-stimulating proteins: c-Myc and pThr183-Erk likewise gene expressions of miR-17-5p and miR-18. Two weeks of VZ treatment showed anxiolytic effect figured by alleviation of hippocampal histological examination. VZ protected β-catenin signal via reduction in Axin-1 and elevation of APC conjugated with modulation of β-catenin downstream targets. The cytoplasmic β-catenin turnover by Axin-1 was restored by XAV939. Herein, VZ showed anti-anxiety effect, which may be in part through regaining the balance of the reduced β-catenin and its subsequent exaggerated response of p-Erk, c-Myc, Dicer-1, miR-17-5p, and miR-18.

Influence of β-catenin signaling on neurogenesis in neuropsychiatric disorders: Anxiety and depression

It has been proven that stress, mainly in the early years of life, can lead to anxiety and mood problems. Current treatments for psychiatric disorders are not enough, and some of them show intolerable side effects, emphasizing the urgent need for new treatment targets. Hence, a better understanding of the different brain networks, which are involved in the response to anxiety and depression, may evoke treatments with more specific targets. One of these targets is β-catenin that regulates brain circuits. β-Catenin has a dual response toward stress, which may influence coping or vulnerability to stress response. Indeed, β-catenin signaling involves several processes such as inflammation-directed brain repair, inflammation-induced brain damage, and neurogenesis. Interestingly, β-catenin reduction is accompanied by low neurogenesis, which leads to anxiety and depression. However, in another state, this reduction activates a compensatory mechanism that enhances neurogenesis to protect against depression but may precipitate anxiety. Thus, understanding the molecular mechanism of β-catenin could enhance our knowledge about anxiety and depression's pathophysiology, potentially improving clinical results by targeting it. Herein, the different states of β-catenin were discussed, shedding light on possible drugs that showed action on psychiatric disorders through β-catenin.

Wnt signaling is involved in crotalphine-induced analgesia in a rat model of neuropathic pain

The aberrant activation of Wnt/β-catenin and atypical Wnt/Ryk signaling pathways in the spinal cord is critical for the development and maintenance of neuropathic pain. Crotalphine is a structural analog to a peptide first identified in Crotalus durissus terrificus snake venom, which induces antinociception by activating kappa-opioid and CB2 cannabinoid receptors. Consistent with previous data, we showed that the protein levels of the canonical Wnt/β-catenin and the atypical Wnt/Ryk signaling pathways are increased in neuropathic rats. Importantly, the administration of crotalphine downregulates these protein levels, including its downstream cascades, such as TCF4 from the canonical pathway and NR2B glutamatergic receptor and Ca2+-dependent signals, via the Ryk receptor. The CB2 receptor antagonist, AM630, abolished the crotalphine-induced atypical Wnt/Ryk signaling pathway activation. However, the selective CB2 agonist affects both canonical and non-canonical Wnt signaling in the spinal cord. Next, we showed that crotalphine blocked hypersensitivity and significantly decreased the concentration of IL-1ɑ, IL-1β, IL-6, IL-10, IL-18, TNF-ɑ, MIP-1ɑ and MIP-2 induced by intrathecal injection of exogenous Wnt-3a agonist. Taken together, our findings show that crotalphine induces analgesia in a neuropathic pain model by down-regulating the canonical Wnt/β-catenin and the atypical Wnt/Ryk signaling pathways and, consequently controlling neuroinflammation. This effect is, at least in part, mediated by CB2 receptor activation. These results open a perspective for new approaches that can be used to target Wnt signaling in the context of chronic pain. PERSPECTIVE: Our work identified that crotalphine-induced activation of CB2 receptors plays a critical role in the impairment of Wnt signaling during neuropathic pain. This work suggests that drugs with opioid/cannabinoid activity may be a useful strategy to target Wnt signaling in the context of chronic pain.

Exendin-4 ameliorates tau hyperphosphorylation and cognitive impairment in type 2 diabetes through acting on Wnt/β-catenin/NeuroD1 pathway

BACKGROUND

Type 2 diabetes (T2D) is an independent risk factor for Alzheimer's disease (AD). Exendin-4 (Ex-4), a widely used glucagon-like peptide-1 receptor agonist drug in the treatment of T2D, has been demonstrated the therapeutic effects on diabetic encephalopathy (DE). Especially, the Ex-4 ameliorates the tau hyperphosphorylation and cognitive impairment in DE. And these crucial alterations are also important bridge between T2D and AD. However, its unique mechanism is unclear.

METHODS

The db/db mice, high-fat-diet (HFD) / streptozotocin (STZ)-induced diabetic (HF-diabetic) mice, and high-glucose-damaged (HGD) HT-22 hippocampal cells were enrolled to examine the effects of Ex-4 on AD-like changes in T2D. The Novel object recognition test (NORT) and Morris water maze test (MWMT) were conducted to evaluate the cognitive impairment. The Dickkopf-1 (DKK1) was employed to weaken the activation of the Wnt/β-catenin pathway to explore the mechanism of Ex-4 in protecting the brain functions. The JASPAR was based to predict the interaction between NeuroD1 and the promoter region of Ins2. Moreover, the chromatin immunoprecipitation coupled with quantitative polymerase chain reaction (ChIP-qPCR) and luciferase reporter assays were performed.

RESULTS

Ex-4 alleviated the tau hyperphosphorylation, increased the brain-derived insulin, and improved the PI3K/AKT/GSK3-β signalling in db/db mice, HF-diabetic mice, and HGD HT-22 hippocampal neuronal cells. The NORT and MWMT indicated that Ex-4 alleviated the learning and memory deficits in HF-diabetic mice. The inhibitor Dickkopf-1 (DKK1) of the Wnt/β-catenin pathway significantly blocked the protective effects of Ex-4. Regarding further molecular mechanisms, NeuroD1 was affected by Ex-4 in vivo and in vitro, and the knockdown or overexpression of NeuroD1 suggested its crucial role in promoting the brain insulin by Ex-4. Meanwhile, the ChIP‒qPCR and luciferase reporter assays confirmed the combination between NeuroD1 and the promoter region of the insulin-encoding gene Ins2. And this interaction could be promoted by Ex-4.

CONCLUSIONS

Our study proposes that Ex-4 alleviates tau hyperphosphorylation and cognitive dysfunction by increasing Ins2-derived brain insulin through the Wnt/β-catenin/NeuroD1 signaling in T2D. And its also show new lights on part of the progress and mechanism on treatment targets for the DE in T2D.

The YTHDF1-TRAF6 pathway regulates the neuroinflammatory response and contributes to morphine tolerance and hyperalgesia in the periaqueductal gray

Long-term use of opioids such as morphine has negative side effects, such as morphine analgesic tolerance and morphine-induced hyperalgesia (MIH). These side effects limit the clinical use and analgesic efficacy of morphine. Elucidation of the mechanisms and identification of feasible and effective methods or treatment targets to solve this clinical phenomenon are important. Here, we discovered that YTHDF1 and TNF receptor-associated factor 6 (TRAF6) are crucial for morphine analgesic tolerance and MIH. The m6A reader YTHDF1 positively regulated the translation of TRAF6 mRNA, and chronic morphine treatments enhanced the m6A modification of TRAF6 mRNA. TRAF6 protein expression was drastically reduced by YTHDF1 knockdown, although TRAF6 mRNA levels were unaffected. By reducing inflammatory markers such as IL-1β, IL-6, TNF-α and NF-κB, targeted reduction of YTHDF1 or suppression of TRAF6 activity in ventrolateral periaqueductal gray (vlPAG) slows the development of morphine analgesic tolerance and MIH. Our findings provide new insights into the mechanism of morphine analgesic tolerance and MIH indicating that YTHDF1 regulates inflammatory factors such as IL-1β, IL-6, TNF-α and NF-κB by enhancing TRAF6 protein expression.

The long-term effects of repeated heroin vapor inhalation during adolescence on measures of nociception and anxiety-like behavior in adult Wistar rats

RATIONALE

Adolescents represent a vulnerable group due to increased experimentation with illicit substances that is often associated with the adolescent period, and because adolescent drug use can result in long-term effects that differ from those caused by drug use initiated during adulthood.

OBJECTIVES

The purpose of the present study was to determine the effects of repeated heroin vapor inhalation during adolescence on measures of nociception, and anxiety-like behavior during adulthood in female and male Wistar rats.

METHODS

Rats were exposed twice daily to 30 min of heroin vapor from post-natal day (PND) 36 to PND 45. At 12 weeks of age, baseline thermal nociception was assessed across a range of temperatures with a warm-water tail-withdrawal assay. Anxiety-like behavior was assessed in an elevated plus-maze (EPM) and activity was measured in an open-field arena. Starting at 23 weeks of age, baseline thermal nociception was re-assessed, nociception was determined after acute heroin or naloxone injection, and anxiety-like behavior was redetermined in the EPM.

RESULTS

Adolescent heroin inhalation altered baseline thermal nociception in female rats at 12 weeks of age and in both female and male rats at ~ 23 weeks. Heroin-treated animals exhibited anxiety-like behavior when tested in the elevated plus-maze, showed blunted heroin-induced analgesia, but exhibited no effect on naloxone-induced hyperalgesia.

CONCLUSIONS

The present study demonstrates that heroin vapor inhalation during adolescence produces behavioral and physiological consequences in rats that persist well into adulthood.

Gene expression associated with human brain activations in facial expression recognition

Previous studies identified some genetic loci of emotion, but few focused on human emotion-related gene expression. In this study, the facial expression recognition (FER) task-based high-resolution fMRI data of 203 subjects in the Human Connectome Project (HCP) and expression data of the six healthy human postmortem brain tissues in the Allen Human Brain Atlas (AHBA) were used to conduct a transcriptome-neuroimaging spatial association analysis. Finally, 371 genes were identified to be significantly associated with FER-related brain activations. Enrichment analyses revealed that FER-related genes were mainly expressed in the brain, especially neurons, and might be related to cell junction organization, synaptic functions, and nervous system development regulation, indicating that FER was a complex polygenetic biological process involving multiple pathways. Moreover, these genes exhibited higher enrichment for psychiatric diseases with heavy emotion impairments. This study provided new insight into understanding the FER-related biological mechanisms and might be helpful to explore treatment methods for emotion-related psychiatric disorders.

Hair Growth Promotion by δ-Opioid Receptor Activation

Literature has revealed that the delta opioid receptor (DOR) exhibited diverse pharmacological effects on neuron and skin. In the present study, we have investigated whether the activation of DOR has hair-growth promotion effects. Compared with other opioid receptor, DOR was highly expressed in epidermal component of hair follicle in human and rodents. The expression of DOR was high in the anagen phase, but it was low in the catagen and telogen phases during mouse hair cycle. Topical application of UFP-512, a specific DOR agonist, significantly accelerated the induction of the anagen in C₃H mice. Topical application of UFP-512 also increased the hair length in hair organ cultures and promoted the proliferation and the migration of outer root sheath (ORS) cells. Similarly, pharmacological inhibition of DOR by naltrindole significantly inhibited the anagen transition process and decreased hair length in hair organ cultures. Thus, we further examined whether Wnt/β-catenin pathway was related to the effects of DOR on hair growth. We found that Wnt/β-catenin pathway was activated by UFP-512 and siRNA for β-catenin attenuated the UFP-512 induced proliferation and migration of ORS cells. Collectively, result established that DOR was involved in hair cycle regulation, and that DOR agonists such as UFP-512 should be developed for novel hair-loss treatment.

P53/miR-154 Pathway Regulates the Epithelial-Mesenchymal Transition in Glioblastoma Multiforme Cells by Targeting TCF12

PURPOSE

Glioblastoma multiforme (GBM) is an aggressive brain tumor with a rather short survival time. Mutation of p53 has been observed and reported to play critical roles in the progression of GBM. However, the pathological mechanisms are still unclear. This study was designed to identify the role of miR-154 in mediating the biological functions of p53 in glioblastoma multiforme.

METHODS

In the current study, the expression of miR-154 in GBM tissue samples and cell lines with wt-p53 or mutant p53 was evaluated. The functions of miR-154 in tumor migration, invasion and epithelial-mesenchymal transition were analyzed in vitro. A luciferase reporter assay was used to identify the target of miR-154.

RESULTS

We found that expression of miR-154 was much lower in patient tissues with mutant p53. Further study revealed that p53 was a transcription factor of miR-154 and that the R273H mutation led to its inactivation. In addition, overexpression of miR-154 remarkably suppressed cell migration, invasion and EMT in vitro and tumor growth in vivo. Moreover, TCF12 was proven to be a direct target of miR-154, and the tumor suppressive effect of miR-154 was reversed by TCF12.

CONCLUSION

Overall, miR-154, which was regulated by wt-p53, inhibited migration, invasion and EMT of GBM cells by targeting TCF12, indicating that miR-154 may act as a biomarker and that the p53/miR-154/TCF12 pathway could be a potential therapeutic target for GBM.

Propoxyphene Mediates Oxyhemoglobin-Induced Injury in Rat Cortical Neurons Through Up-Regulation of Active-β-Catenin

Wnt/β-catenin signaling is involved in various biological processes, including the development of the central nervous system. The dysfunction of mitochondria has been shown to participate in the progress of subarachnoid hemorrhage (SAH). Traumatic subarachnoid hemorrhage (tSAH) is a serious complication in acute craniocerebral trauma. Opioids can activate the canonical Wnt/β-catenin signaling pathway. c-Myc, a downstream protein of Wnt/β-catenin signaling, contributes to the fusion of mitochondria. Here, we investigated the protective roles of Propoxyphene (Pro) against Oxyhemoglobin (OxyHb)-induced primary cultured neuron apoptosis. The data indicated that Pro rescued active-β-catenin from OxyHb-induced decline. Furthermore, Pro attenuated OxyHb-induced apoptosis and fission of mitochondria in primary cortical neurons. However, the protective effects were abrogated under active-β-catenin-deficient conditions. Together, the data presented here showed that Pro, a weak opioid analgesic drug, attenuates OxyHb-induced mitochondria-dependent apoptosis in an active-β-catenin-c-Myc-dependent manner.

Synergistic effect between citalopram and citicoline on anxiolytic effect in non-sensitized and morphine-sensitized mice: An isobologram analysis

In the present study, the effects of intraperitoneal (i.p.) injections of citalopram and citicoline on morphine-induced anxiolytic effects were investigated in non-sensitized and morphine-sensitized mice using elevated plus-maze (EPM). Subcutaneous (s.c.) administration morphine (5 mg/kg) increased the percentage of open arm time (%OAT, in morphine-sensitized mice), and open arm entries (%OAE, in non-sensitized mice), but not a locomotor activity, indicating an anxiolytic response to morphine. On the other hand, i.p. administration of naloxone decreased %OAT (morphine-sensitized mice), and %OAE (non-sensitized and morphine-sensitized mice), but not a locomotor activity, showing an anxiogenic effect to naloxone. Moreover, i.p.co-administration of citalopram (5 and 10 mg/kg) and citicoline (75 mg/kg) induced the anxiolytic effect. Interestingly, i.p. co-administration of low doses of citalopram (0.5, 1 and 2.5 mg/kg) and citicoline (25 mg/kg) significantly increased %OAT and %OAE in non-sensitized as well as %OAT in morphine-sensitized mice, indicating an anxiolytic effect. An isobolographic analysis of data was performed, presenting a synergistic interaction between citalopram and citicoline upon the production of anxiolytic effect in non-sensitized and morphine-sensitized mice. In conclusion, it seems that (1) morphine sensitization affects the anxiety behavior in the EPM, (2) μ-opioid receptors play an important role in morphine anxiolytic effect, (3) citalopram and citicoline induced anti-anxiety effect, (4) a synergistic effect of citalopram and citicoline upon induction of anti-anxiety behavior in non-sensitized and morphine-sensitized mice.

Endogenous opiates and behavior: 2017

This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Loss of Sfrp2 contributes to the neurological disorders related with morphine withdrawal via Wnt/β-catenin signaling

Morphine administration is a medical problem characterized by compulsive opioid use that causes terrible negative consequences. The exact mechanisms of morphine-induced dependence and morphine withdrawal symptoms remain unclear. Recent studies have revealed that the upregulation of Wnt/β-catenin signaling plays important roles in morphine exposure and morphine withdrawal. Secreted frizzled-related protein 2 (Sfrp2) can prevent the activation of Wnt/β-catenin signaling by competing with the Frizzled receptor for Wnt ligands. We conducted this study aimed to evaluate the effect of iatrogenic trauma induced by stereotactic surgery and the protective effect of stereotaxic Sfrp2 injection on morphine withdrawal symptoms in Male Sprague Dawley (SD) rats. Many techniques including western blot analysis and immunoprecipitation were used. Anxiety-related behaviors, morphine withdrawal syndrome, and dendritic spines were also examined in male SD rats after morphine treatment and stereotaxic injection of Sfrp2. Western blot results suggested that Wnt signaling was activated in the nucleus accumbens of SD rats suffering from morphine withdrawal and that Sfrp2 attenuated the overexpression of Wnt signaling. Similarly, the withdrawal-like symptoms of morphine dependent rats were abrogated by intracerebral Sfrp2 injection. The iatrogenic trauma induced by stereotactic surgery showed no influence on the Wnt signaling and withdrawal-like symptoms. Moreover, the results of Golgi-cox staining and DiI staining indicated that the damage on proximal spine density caused by morphine treatment was restored by intracerebral Sfrp2 injection. Together, the data presented here indicated that Sfrp2 abrogated the neurological disorders and loss of proximal spine related with morphine withdrawal via Wnt/β-catenin signaling.

Wnt7a in Mouse Insular Cortex Contributes to Anxiety-like Behavior During Protracted Abstinence from Morphine

Anxiety is considered an important protracted abstinence symptom that can aggravate craving and relapse risk in opioid addicts. Although the insular cortex (IC) has been reported to be a key brain region in mediating emotional and motivational alterations induced by drug consumption and withdrawal, the role of IC in anxiety related to protracted abstinence remains elusive. In this study, we found that: (1) anxiety-like behavior in morphine-dependent mice became significant after 28 days of withdrawal, while their physical symptoms became undetectable. (2) Activated glutamatergic neurons in the medial IC, but not the anterior or posterior IC were significantly increased after 28 days of withdrawal. Bilateral lesion of the medial IC, but not the anterior or posterior IC with ibotenic acid (IBO) alleviated the anxiety-like behavior. (3) Expression of Wnt7a in the medial IC was significantly increased after 28 days of withdrawal, and specific down-regulation of Wnt7a with AAV-shWnt7a also alleviated the anxiety-like behavior. The findings reveal the medial IC is involved in mediating anxiety-like behavior related to morphine protracted abstinence, in which Wnt7a plays a critical role.

GSK-3β Inhibitor Alsterpaullone Attenuates MPP+-Induced Cell Damage in a c-Myc-Dependent Manner in SH-SY5Y Cells

Mitochondrial dysfunction plays significant roles in the pathogenesis of Parkinson’s Disease (PD). The inactivation of c-Myc, a down-stream gene of Wnt/β-catenin signaling, may contribute to the mitochondria dysfunction. Inhibition of glycogen synthase kinase 3β (GSK-3β) with Alsterpaullone (Als) can activate the down-stream events of Wnt signaling. Here, we investigated the protective roles of Als against MPP⁺-induced cell apoptosis in SH-SY5Y cells. The data showed that Als effectively rescued c-Myc from the MPP⁺-induced decline via Wnt signaling. Furthermore, Als protected SH-SY5Y cells from the MPP⁺-induced mitochondrial fission and cell apoptosis. However, the protective roles of Als were lost under β-catenin-deficient conditions. These findings indicate that Als, a GSK-3β inhibitor, attenuated the MPP⁺-induced mitochondria-dependent apoptotic via up-regulation of the Wnt signaling.

Pentazocine Protects SN4741 Cells Against MPP+-Induced Cell Damage via Up-Regulation of the Canonical Wnt/β-Catenin Signaling Pathway

The Wnt/β-catenin signaling pathway has been linked to many neurodegenerative diseases including Parkinson’s disease (PD). A glycoprotein named Dickkopf-1 (Dkk1) can combine with the receptor complex on cell membrane to inhibit Wnt/β-catenin signaling. Opioids, a series of compounds including morphine, fentanyl and pentazocine, have been reported to contribute to the up-regulation of Wnt/β-catenin signaling. Naloxone is an antagonist that has been used as an antidote to opioids through mu-opioid receptor. 1-methyl-4-phenylpyridinium (MPP⁺), which serves as a selective toxin for dopaminergic neurons, has been used to create experimental models of PD. In our study, we examined the protective effects of pentazocine against MPP⁺-induced cell death in the nigral dopaminergic cell line, SN4741 and tried to elucidate the molecular mechanisms underlying such protective effects. The data showed that pretreatment with pentazocine significantly rescued the SN4741 cell against MPP⁺. Moreover, the MPP⁺-exposed SN4741 cells exhibited a down-regulation of β-catenin, which could be restored by treatment with pentazocine. However, Dkk1 but not naloxonewas associated with the abrogation of protective effect of pentazocine. These results suggest that pentazocine alleviates MPP⁺-induced SN4741 cells apoptosis via the up-regulation of canonical Wnt/β-catenin signaling.