Anti-inflammation effects of naloxone involve phosphoinositide 3-kinase delta and gamma

Caffeine and naloxone treated mesenchymal stem cells improve symptoms and reduce inflammation in a mouse model of ulcerative colitis

BACKGROUND AND OBJECTIVE

Ulcerative colitis (UC) causes ulcers in the colon and rectum, leading to abdominal pain, diarrhea, and rectal bleeding, and if left untreated, can lead to serious complications. The therapeutic effects of mesenchymal stem cells (MSCs) on experimental models of UC have been proven. Since the microenvironment around these cells is crucial in maintaining cell proliferation, differentiation, metabolism, and overall function, this study aims to evaluation the role of caffeine and naloxone as a new microenvironment for MSCs in reducing inflammation and improving symptoms in an experimental model of UC.

MATERIAL AND METHOD

A group of 40 outbred NMRI mice were studied and divided randomly into four equal groups (N = 10 each group). UC was induced in all groups using acetic acid. The first group (control) was treated with phosphate buffer saline (PBS), the second group with MSCs-Caffeine, the third with MSCs-Naloxone, and the fourth with Mesalazine. The disease activity index (DAI), tissue damage, myeloperoxidase (MPO) activity, nitric oxide (NO) levels, and the production of IL-1, IL-6, and TNF-α cytokines were evaluated.

RESULT

Our research demonstrated that all treatments were effective in improving the symptoms and reducing inflammatory markers in mice with colitis. Among the two MSCs treatments, the MSCs-Caffeine was found to be the most potent in reducing the levels of NO, IL-1, IL-6, tissue damage (P < 0.001) and as well as TNF-α (P < 0.0001) in compared to the control group.

CONCLUSION

MSCs treated with caffeine and naloxone can enhance the immunoregulatory potential of these. As a result, treated MSCs can lead to improved clinical signs and reduced inflammatory parameters in mice with UC, making this approach a useful way for controlling and treating the disease. However, additional research is needed to access the mechanism behind the stronger immune system regulatory effects of treated MSCs in UC treatment.

Inhibition of the NLRP3 Inflammasome Activation/Assembly through the Activation of the PI3K Pathway by Naloxone Protects Neural Stem Cells from Ischemic Condition

Naloxone is a well-known opioid antagonist and has been suggested to have neuroprotective effects in cerebral ischemia. We investigated whether naloxone exhibits anti-inflammatory and neuroprotective effects in neural stem cells (NSCs) injured by oxygen-glucose deprivation (OGD), whether it affects the NOD-like receptor protein 3 (NLRP3) inflammasome activation/assembly, and whether the role of the phosphatidylinositol 3-kinase (PI3K) pathway is important in the control of NLRP3 inflammasome activation/assembly by naloxone. Primary cultured NSCs were subjected to OGD and treated with different concentrations of naloxone. Cell viability, proliferation, and the intracellular signaling proteins associated with the PI3K pathway and NLRP3 inflammasome activation/assembly were evaluated in OGD-injured NSCs. OGD significantly reduced survival, proliferation, and migration and increased apoptosis of NSCs. However, treatment with naloxone significantly restored survival, proliferation, and migration and decreased apoptosis of NSCs. Moreover, OGD markedly increased NLRP3 inflammasome activation/assembly and cleaved caspase-1 and interleukin-1β levels in NSCs, but naloxone significantly attenuated these effects. These neuroprotective and anti-inflammatory effects of naloxone were eliminated when cells were treated with PI3K inhibitors. Our results suggest that NLRP3 inflammasome is a potential therapeutic target and that naloxone reduces ischemic injury in NSCs by inhibiting NLRP3 inflammasome activation/assembly mediated by the activation of the PI3K signaling pathway.

The role of phosphoinositide 3-kinases in immune-inflammatory responses: potential therapeutic targets for abdominal aortic aneurysm

The pathogenesis of abdominal aortic aneurysm (AAA) includes inflammatory responses, matrix metalloproteinases (MMPs) degradation, VSMC apoptosis, oxidative stress, and angiogenesis, among which the inflammatory response plays a key role. At present, surgery is the only curing treatment, and no effective drug can delay AAA progression in clinical practice. Therefore, searching for a signaling pathway related to the immune-inflammatory response is an essential direction for developing drugs targeting AAA. Recent studies have confirmed that the PI3K family plays an important role in many inflammatory diseases and is involved in regulating various cellular functions, especially in the immune-inflammatory response. This review focuses on the role of each isoform of PI3K in each stage of AAA immune-inflammatory response, making available explorations for a deeper understanding of the mechanism of inflammation and immune response during the formation and development of AAA.

Targeting Toll-like receptor-4 to tackle preterm birth and fetal inflammatory injury

Every year, 15 million pregnancies end prematurely, resulting in more than 1 million infant deaths and long-term health consequences for many children. The physiological processes of labour and birth involve essential roles for immune cells and pro-inflammatory cytokines in gestational tissues. There is compelling evidence that the mechanisms underlying spontaneous preterm birth are initiated when a premature and excessive inflammatory response is triggered by infection or other causes. Exposure to pro-inflammatory mediators is emerging as a major factor in the 'fetal inflammatory response syndrome' that often accompanies preterm birth, where unscheduled effects in fetal tissues interfere with normal development and predispose to neonatal morbidity. Toll-like receptors (TLRs) are critical upstream gatekeepers of inflammatory activation. TLR4 is prominently involved through its ability to sense and integrate signals from a range of microbial and endogenous triggers to provoke and perpetuate inflammation. Preclinical studies have identified TLR4 as an attractive pharmacological target to promote uterine quiescence and protect the fetus from inflammatory injury. Novel small-molecule inhibitors of TLR4 signalling, specifically the non-opioid receptor antagonists (+)-naloxone and (+)-naltrexone, are proving highly effective in animal models for preventing preterm birth induced by bacterial mimetic LPS, heat-killed Escherichia coli, or the TLR4-dependent pro-inflammatory lipid, platelet-activating factor (PAF). Here, we summarise the rationale for targeting TLR4 as a master regulator of inflammation in fetal and gestational tissues, and the potential utility of TLR4 antagonists as candidates for preventative and therapeutic application in preterm delivery and fetal inflammatory injury.

Toll-Like Receptor-4 Antagonist (+)-Naloxone Confers Sexually Dimorphic Protection From Inflammation-Induced Fetal Programming in Mice

Inflammation elicited by infection or noninfectious insults during gestation induces proinflammatory cytokines that can shift the trajectory of development to alter offspring phenotype, promote adiposity, and increase susceptibility to metabolic disease in later life. In this study, we use mice to investigate the utility of a small molecule Toll-like receptor (TLR)4 antagonist (+)-naloxone, the nonopioid isomer of the opioid receptor antagonist (-)-naloxone, for mitigating altered fetal metabolic programming induced by a modest systemic inflammatory challenge in late gestation. In adult progeny exposed to lipopolysaccharide (LPS) challenge in utero, male but not female offspring exhibited elevated adipose tissue, reduced muscle mass, and elevated plasma leptin at 20 weeks of age. Effects were largely reversed by coadministration of (+)-naloxone following LPS. When given alone without LPS, (+)-naloxone elicited accelerated postweaning growth and elevated muscle and fat mass in adult male but not female offspring. LPS induced expression of inflammatory cytokines Il1a, Il1b, Il6, Tnf, and Il10 in fetal brain, placental, and uterine tissues, and (+)-naloxone suppressed LPS-induced cytokine expression. Fetal sex-specific regulation of cytokine expression was evident, with higher Il1a, Il1b, Il6, and Il10 induced by LPS in tissues associated with male fetuses, and greater suppression by (+)-naloxone of Il6 in females. These data demonstrate that modulating TLR4 signaling with (+)-naloxone provides protection from inflammatory diversion of fetal developmental programming in utero, associated with attenuation of gestational tissue cytokine expression in a fetal sex-specific manner. The results suggest that pharmacologic interventions targeting TLR4 warrant evaluation for attenuating developmental programming effects of fetal exposure to maternal inflammatory mediators.

Behavioral, histopathological, and biochemical evaluations on the effects of cinnamaldehyde, naloxone, and their combination in morphine-induced cerebellar toxicity

Long-term morphine use for therapeutic approaches may lead to serious side effects. Several studies have suggested opioid antagonist and antioxidant therapy for reducing adverse effects of morphine. Cinnamaldehyde has a potent anti-oxidant property. In this study, separate and combined effects of cinnamaldehyde and naloxone (an opioid receptor antagonist) on behavioral changes and cerebellar histological and biochemical outcomes were investigated after long-term morphine administration. Seventy-eight rats were divided into two major morphine-treated and morphine-untreated groups. Morphine-treated group was subdivided into seven subgroups for receiving vehicle, normal saline, cinnamaldehyde (1.25, 5, and 20 mg/kg), naloxone, and cinnamaldehyde plus naloxone before morphine. Morphine-untreated group was subdivided into six subgroups and treated with vehicle, cinnamaldehyde (1.25, 5, and 20 mg/kg), naloxone, and their combination. Chemical compounds were administered for 28 consecutive days. Behavioral tests including footprint, rotarod, and beam balance tests were employed. Histopathological and biochemical alterations of cerebellum were determined. Body and cerebellum weights, stride width, time spent on the rotarod, Purkinje cell number, thickness of molecular and granular layers, superoxide dismutase (SOD), and total antioxidant capacity (TAC) decreased as a result of administrating morphine. Morphine increased beam transverse time, malondealdehyde (MDA), tumor necrosis factor-α (TNF-α), and caspase-3 levels. Histopathological changes such as cellular vacuolation and loss were also produced as a result of treatment with morphine. Cinnamaldehyde, naloxone, and their combination treatments improved all the above-mentioned alterations induced by morphine. We concluded that cinnamaldehyde produced a neuroprotective effect through anti-oxidant, anti-inflammatory, apoptotic, and probably naloxone-sensitive opioid receptor interaction mechanisms.

Evidence for a dynorphin-mediated inner ear immune/inflammatory response and glutamate-induced neural excitotoxicity: an updated analysis

Acoustic overstimulation (AOS) is defined as the stressful overexposure to high-intensity sounds. AOS is a precipitating factor that leads to a glutamate (GLU)-induced Type I auditory neural excitotoxicity and an activation of an immune/inflammatory/oxidative stress response within the inner ear, often resulting in cochlear hearing loss. The dendrites of the Type I auditory neural neurons that innervate the inner hair cells (IHCs), and respond to the IHC release of the excitatory neurotransmitter GLU, are themselves directly innervated by the dynorphin (DYN)-bearing axon terminals of the descending brain stem lateral olivocochlear (LOC) system. DYNs are known to increase GLU availability, potentiate GLU excitotoxicity, and induce superoxide production. DYNs also increase the production of proinflammatory cytokines by modulating immune/inflammatory signal transduction pathways. Evidence is provided supporting the possibility that the GLU-mediated Type I auditory neural dendritic swelling, inflammation, excitotoxicity, and cochlear hearing loss that follow AOS may be part of a brain stem-activated, DYN-mediated cascade of inflammatory events subsequent to a LOC release of DYNs into the cochlea. In support of a DYN-mediated cascade of events are established investigations linking DYNs to the immune/inflammatory/excitotoxic response in other neural systems.

In contrast to morphine, buprenorphine enhances macrophage-induced humoral immunity and, as oxycodone, slightly suppresses the effector phase of cell-mediated immune response in mice

BACKGROUND

Opioid receptors are commonly expressed on various immune cells, macrophages especially. Thus, these cells are prone to stimulation with opioids, which seems to be responsible for opioid-induced immunomodulatory effects. While morphine, fentanyl and methadone influence on mouse immune response was recently studied, little is known about the potential immunomodulatory impact of buprenorphine and oxycodone.

AIM

The current research aimed to investigate the influence of buprenorphine and oxycodone on immune responses in mice under homeostatic conditions.

METHODS AND RESULTS

Repeated administration of morphine led to intensification of CHS response in actively sensitized mice, while buprenorphine or oxycodone administration exerted the opposite effect. Further, hapten-conjugated macrophages from mice treated with morphine, when transferred into naive recipients, induced more potent CHS response. The enhanced generation of reactive oxygen intermediates and nitric oxide by macrophages from mice treated with buprenorphine, oxycodone or morphine was also shown, along with increased release of IL-6, TNFα and TGFβ. Treatment with opioids altered expression of antigen phagocytosis and presentation markers. Finally, the inhibitory effect of morphine treatment on induction of humoral immunity by macrophages was demonstrated, while oxycodone failed to influence humoral immune response and buprenorphine actually enhanced B-cell activation.

CONCLUSIONS

Current observations confirm that macrophages greatly contribute to immunomodulatory effects of opioids. Studies on immunomodulation by opioids have great importance related to the evaluation of its beneficial and adverse effects on patient condition. Our research showed that oxycodone exerts the weakest immunomodulatory properties, allowing us to assume this drug as safer than morphine during prolonged therapy.

Heterogeneity of atherosclerotic plaque macrophage origin, phenotype and functions: Implications for treatment

Macrophages are key players in atherosclerotic lesions, regulating the local inflammatory milieu and plaque stability by the secretion of many inflammatory molecules, growth factors and cytokines. Monocytes have long been considered to be the main source of plaque macrophages. However, recent findings provide evidence for proliferation of local macrophages or transdifferentiation from other vascular cells as alternative sources. Recent years of research focused on the further identification and characterisation of macrophage phenotypes and functions. In this review we describe the advances in our understanding of monocyte and macrophage heterogeneity and its implications for specific therapeutic interventions, aiming to reduce the ever growing significant risk of cardiovascular events without any detrimental side effects on the patient's immune response.

Akt Signaling Pathway in Macrophage Activation and M1/M2 Polarization

Macrophages become activated initiating innate immune responses. Depending on the signals, macrophages obtain an array of activation phenotypes, described by the broad terms of M1 or M2 phenotype. The PI3K/Akt/mTOR pathway mediates signals from multiple receptors including insulin receptors, pathogen-associated molecular pattern receptors, cytokine receptors, adipokine receptors, and hormones. As a result, the Akt pathway converges inflammatory and metabolic signals to regulate macrophage responses modulating their activation phenotype. Akt is a family of three serine-threonine kinases, Akt1, Akt2, and Akt3. Generation of mice lacking individual Akt, PI3K, or mTOR isoforms and utilization of RNA interference technology have revealed that Akt signaling pathway components have distinct and isoform-specific roles in macrophage biology and inflammatory disease regulation, by controlling inflammatory cytokines, miRNAs, and functions including phagocytosis, autophagy, and cell metabolism. Herein, we review the current knowledge on the role of the Akt signaling pathway in macrophages, focusing on M1/M2 polarization and highlighting Akt isoform-specific functions.

Recent advances in the prevention of preterm birth

Preterm birth (PTB) remains a major obstetric healthcare problem and a significant contributor to perinatal morbidity, mortality, and long-term disability. Over the past few decades, the perinatal outcomes of preterm neonates have improved markedly through research and advances in neonatal care, whereas rates of spontaneous PTB have essentially remained static. However, research into causal pathways and new diagnostic and treatment modalities is now bearing fruit and translational initiatives are beginning to impact upon PTB rates. Successful PTB prevention requires a multifaceted approach, combining public health and educational programs, lifestyle modification, access to/optimisation of obstetric healthcare, effective prediction and diagnostic modalities, and the application of effective, targeted interventions. Progress has been made in some of these areas, although there remain areas of controversy and uncertainty. Attention is now being directed to areas where greater gains can be achieved. In this mini-review, we will briefly and selectively review a range of PTB prevention strategies and initiatives where progress has been made and where exciting opportunities await exploitation, evaluation, and implementation.

Naloxone inhibits nod-like receptor protein 3 inflammasome

BACKGROUND

Naloxone, an opioid receptor antagonist, possesses potent anti-inflammation effects. We previously confirmed the effects of naloxone on inhibiting upregulation of inflammatory cytokine interleukin-1β (IL-1β). Production of mature form IL-1β is mediated by the nod-like receptor protein 3 (NLRP3) inflammasome, a multiprotein complex composed of NLRP3, and the adaptor protein apoptosis-associated speck-like protein contains a caspase recruitment domain (ASC). We elucidated whether naloxone could inhibit the activation of NLRP3 inflammasome.

MATERIAL AND METHODS

To induce IL-1β production and NLRP3 inflammasome activation, the human monocytic leukemia cell line THP-1 cells were first primed with lipopolysaccharide (LPS, 1 μg/mL) and then activated with adenosine triphosphate (ATP, 1 mM). For NLRP3 transcription, THP-1 cells were only treated with LPS priming.

RESULTS

Enzyme-link immunosorbent assay data revealed that the concentration of IL-1β in THP-1 cells treated with LPS plus ATP was significantly higher than that in THP-1 cells treated with LPS plus ATP plus naloxone (0.1 μM) (P < 0.001). Real-time quantitative reverse transcription and polymerase chain reaction data also revealed that NLRP3 mRNA concentration in THP-1 cells treated with LPS was significantly higher than that in THP-1 cells treated with LPS plus naloxone (P = 0.001). ASC speck formation, that is, ASC assembles into a large protein complex, is an indicator for NLRP3 inflammasome activation. Our data revealed that the percentage of cells containing ASC specks in THP-1 cells treated with LPS plus ATP was also significantly higher than that in THP-1 cells treated with LPS plus ATP plus naloxone (P < 0.001).

CONCLUSIONS

Naloxone inhibits NLRP3 inflammasome activation.

Novel Toll-like receptor-4 antagonist (+)-naloxone protects mice from inflammation-induced preterm birth

Toll-like receptor 4 (TLR4) activation by bacterial infection, or by sterile inflammatory insult is a primary trigger of spontaneous preterm birth. Here we utilize mouse models to investigate the efficacy of a novel small molecule TLR4 antagonist, (+)-naloxone, the non-opioid isomer of the opioid receptor antagonist (−)-naloxone, in infection-associated preterm birth. Treatment with (+)-naloxone prevented preterm delivery and alleviated fetal demise in utero elicited by i.p. LPS administration in late gestation. A similar effect with protection from preterm birth and perinatal death, and partial correction of reduced birth weight and postnatal mortality, was conferred by (+)-naloxone administration after intrauterine administration of heat-killed E. coli. Local induction by E. coli of inflammatory cytokine genes Il1b, Il6, Tnf and Il10 in fetal membranes was suppressed by (+)-naloxone, and cytokine expression in the placenta, and uterine myometrium and decidua, was also attenuated. These data demonstrate that inhibition of TLR4 signaling with the novel TLR4 antagonist (+)-naloxone can suppress the inflammatory cascade of preterm parturition, to prevent preterm birth and perinatal death. Further studies are warranted to investigate the utility of small molecule inhibition of TLR-driven inflammation as a component of strategies for fetal protection and delaying preterm birth in the clinical setting.

Endogenous opiates and behavior: 2014

This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants).