Oxycodone-Mediated Activation of the Mu Opioid Receptor Reduces Whole Brain Functional Connectivity in Mice.

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.

Diarylheptanoid Hirsutenone Attenuates Osteoclastogenesis by Suppressing IFNγ and NF-κB Signaling in Th1 and Preosteoclastic Cells.

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-1ß, 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.

The anti-aging properties of a human placental hydrolysate combined with dieckol isolated from Ecklonia cava.

BACKGROUNDS: In 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. METHODS: The 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. RESULTS: Our 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. CONCLUSIONS: Based 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.

An Aß42 uptake and degradation via Rg3 requires an activation of caveolin, clathrin and Aß-degrading enzymes in microglia.

We demonstrated previously that ginsenoside Rg3 enhances the expression of macrophage scavenger receptor class A (SRA) and amyloid ß peptide 1-42 (Aß42) uptake in BV2 cells. In this study, we investigated the biochemical and mechanistic roles of Rg3 in human microglia and animal models to identify the determinants that participate in restoring memory and learning in brains disrupted by the Aß42 peptide. SRA was expressed highly in Rg3-treated rats, and learning and memory functions were maintained at a normal level after the infusion of Aß42. SRA-transfected HMO6 human microglial cells (HMO6.hSRA) overexpressed SRA and took up a remarkable amount of Aß42. Rg3-treated HMO6 cells showed highly enhanced SRA expression and dramatically promoted Aß42 uptake. Moreover, high levels of clathrin and caveolin1 supported the roles of Rg3 in endocytic biogenesis by activating p38 and extracellular signal-regulated protein kinase signaling. Notably, both neprilysin (NEP) and insulin-degrading enzyme (IDE) were significantly expressed by Rg3, suggesting independent and compensatory hydrolytic activity for the Aß peptide. In conclusion, Rg3 successfully triggered Aß42 uptake via SRA and clathrin-/caveolae-mediated endocytic mechanisms and further contributed to accelerate the degradation of Aß peptide via the increase of intracellular NEP and IDE, which may be a promising Alzheimer׳s disease therapy.