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Oxycodone is a potent medicinal opioid analgesic to treat pain. It is also addictive and a main cause for the current opioid crisis. At present, the impact of oxycodone on coordinated brain network activities, and contribution of the mu opioid receptor (MOR) to these effects, is unknown. We used pharmacological magnetic resonance imaging in mice to characterize MOR-mediated oxycodone effects on whole-brain functional connectivity (FC). Control (CTL) and MOR knockout (KO) animals were imaged under dexmedetomidine in a 7Tesla scanner. Acquisition was performed continuously before and after 2 mg/kg oxycodone administration (analgesic in CTL mice). Independent component analysis (data-driven) produced a correlation matrix, showing widespread oxycodone-induced reduction of FC across 71 components. Isocortex, nucleus accumbens (NAc), pontine reticular nucleus, and periacqueducal gray (PAG) components showed the highest number of significant changes. Seed-to-voxel FC analysis (hypothesis-driven) was then focused on PAG and NAc considered key pain and reward centers. The two seeds showed reduced FC with 8 and 22 Allen Brain Atlas-based regions, respectively, in CTL but not KO mice. Further seed-to-seed quantification showed highest FC modifications of both PAG and NAc seeds with hypothalamic and amygdalar areas, as well as between them, revealing the strongest impact across reward and aversion/pain centers of the brain. In conclusion, we demonstrate that oxycodone reduces brain communication in a MOR-dependent manner, and establish a preliminary whole-brain FC signature of oxycodone. This proof-of-principle study provides a unique platform and reference data set to test other MOR opioid agonists and perhaps discover new mechanisms and FC biomarkers predicting safer analgesics.

BackgroundsIn the present study, we aimed to examine the anti-aging properties of human placental hydrolysate (HPE) and dieckol (DE) from Ecklonia cava against free radical scavenging, muscle hypertrophy-related follistatin mRNA expression, amelioration of cognition-related genes and proteins, inhibition of collagenase-regulating genes, and elastinase activity.MethodsThe anti-aging effects were examined in human fibroblast (CCD986sk), mouse myoblast (C2C12), and neuroblastoma (N2a) cell models, by employing various assays such as 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) scavenging, hydroxyl radical-mediated oxidation, quantitative real-time polymerase chain reaction, enzyme activity, and immunocytochemistry observation.ResultsOur results show that HPE combined with DE (HPE:DE) strongly scavenged DPPH radicals and protected proteins against degradation by hydroxyl radical attack. HPE:DE effectively inhibited matrix metalloproteinase-1 expression, protein kinase C alpha expression, and elastinase activity. Furthermore, HPE:DE improved the expression of cognition-related genes (choline acetyltransferase and vesicular acetylcholine transporter). These events may proactively contribute to retard the aging processes and the abrupt physiological changes probably induced by mitochondrial dysfunction with aging.ConclusionsBased on these findings, we conclude that the combined treatment of HPE:DE may be useful for anti-aging therapy in which the accumulation of oxidative damage is the main driving force.

The aim of the present study was to examine the inhibitory roles and mechanisms of hirsutenone (HTN) in the regulation of osteoclastogenesis. Gene levels were compared to assure the effects of HTN on osteoclastogenesis in mouse splenocytes/CD4 T cells, mouse macrophage-like cell line RAW264.7 (preosteoclast), MG63 (osteoblast), and RPMI1788 (B cell) cells. The mechanism by which HTN regulates the degradation of tumor necrosis factor receptor-associated factor 6 (TRAF6) and inhibits inhibitor of kappaB (IκB) and nuclear factor-kappaB (NF-κB) signaling was examined by Western blotting and luciferase reporter assays. Our results demonstrated that HTN effectively downregulated the expression of interferon γ (IFNγ), interleukin-22 (IL-22), IL-1β, and tartrate-resistant acid phosphatase (TRAP) in splenocyte-/CD4 -RAW264.7 co-culture system. Moreover, receptor activator of nuclear factor-κB ligand (RANKL) and CD25 expression were also significantly inhibited in MG63 and CD4 single culture system, suggesting an additional independent effect of HTN on osteoclastogenesis. Notably, TRAF6 was markedly degraded along with a decrease in nuclear factor of activated T-cells (NFATc) and NF-κB activities in RAW264.7 cells. Finally, we concluded that HTN directly or indirectly inhibits osteoclastogenesis via the inhibition of NF-κB signaling by promoting TRAF6 degradation, and plays a crucial role in suppressing the expression of RANKL and cytokines expressed in IFNγ-producing T-helper 1 (Th1) cells. These findings suggest that HTN may be a promising therapeutic candidate for diseases resulting from bone loss.Key words osteoclastogenesis; hirsutenone; interferon γ; receptor activator of nuclear factor-κB ligand; tumor necrosis factor receptor-associated factor 6 Bone serves as an ion reservoir for the body, as well as the location of several specialized bone cells, such as osteoblasts, osteocytes, and osteoclasts, which reside within this complex tissue.1,2) Bone loss, which may induce an imbalance between bone formation and resorption, as a result of aging and after menopause, can lead to osteoporosis, which is characterized by reduced bone mass, deterioration of bone architecture, and an increased risk of fatal bone fractures.3,4) Osteoclasts (OC), the bone-resorbing cells generated from the same precursors as monocyte/macrophages, crosstalk with activated T cells to form activated osteoclasts directly by producing interleukin-7 (IL-7) and receptor activator of nuclear factor-κB ligand (RANKL), and indirectly by promoting the production of RANKL by osteoblasts and fibroblasts via the production of pro-inflammatory cytokines (i.e., IL-1, -6, -17, and interferon (IFN)-γ).5,6) Of these, interleukin-1β (IL-1β), one of the most well-known proinflammatory cytokines, has been reported as an effective stimulator of bone resorption through the upregulation of RANKL.7) In addition, IL-22 produced by activated T cells has been shown to promote osteoclastogenesis, leading to bone erosion in rheumatoid arthritis. 8)As the binding of RANKL to...