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An 8-membered 3-acetoxydioxocanone and dioxocan-2-en-1-one were synthesized by the reaction of 2-(3'-diazo-2'-oxopropyl)-2-methyldioxane with AcOH. The Rh(II)-catalyzed reaction was characterized by the Stevens rearrangement of the bicyclooxonium ylides after protonation by NuH and ring enlargement. The ring enlargement reaction was also dependent on the function of the strained bicyclooxonium ylide intermediates including the stability of the ylides and their ring-opened monocyclic zwitterion.

Microglia are the primary immune cells of the central nervous system and crucial to proper development and maintenance of the brain. Microglia have been recognized to be associated with neurodegenerative diseases and neuroinflammatory disorders. CX3C chemokine receptor 1 (CX3CR1), which is specifically expressed in microglia, regulates microglia homeostatic functions such as microglial activation and is downregulated in aged brain and disease‐associated microglia in rodents, yet its role in human microglia is not fully understood. In this study, we investigated the function of CX3CR1 in human microglia using human induced pluripotent stem (iPS) cell‐derived microglia‐like cells. Human iPS cell‐derived microglia‐like cells expressed microglial markers and showed an activated state and phagocytic activity. Using CRISPR/Cas9 genome editing, we deleted CX3CR1 in human iPS cells and found increased inflammatory responses and phagocytic activity in mutant as compared to wild‐type microglia‐like cells. In addition, the CX3C chemokine ligand 1 (CX3CL1, a ligand for CX3CR1) significantly decreased the upregulation of IL‐6 by lipopolysaccharide stimulation in human iPS cell‐derived microglia‐like cells. These results suggest that CX3CR1 in human microglia may contribute to microglial homeostasis by regulating inflammatory response and phagocytosis. [ABSTRACT FROM AUTHOR]

Objectives: The (+)-isomer of indeloxazine AS1069562 has multiple pharmacological actions, such as serotonin (5-HIT) and norepinephrine (NE) reuptake inhibition and analgesic effects in animal models of neuropathic pain. Here, we investigated the analgesic effects of AS1069562 in rat models of inflammatory and noninflammatory nociceptive pain. Methods: Adjuvant-induced arthritis (AIA) and bradykinin-induced knee joint pain were used as rat models of inflammatory pain. The chronic phase of monoiodoacetate-induced arthritis (MIA) was used as a rat model of noninflammatory pain. Analgesic effects were evaluated by weight-bearing deficit in the AIA and MIA models and by pain response in the bradykinin-induced knee joint pain model. Results: In the AIA model and the bradykinin-induced knee joint pain model, AS1069562 significantly ameliorated the pain-related behavior of weight-bearing deficit and the pain response, respectively. AS1069562 also significantly improved the pain-related behavior of weight-bearing deficit in the chronic phase of the MIA model. Further, following monoiodoacetate injection, repeated administration of AS1069562 or duloxetine significantly improved weight-bearing deficit in the MIA model. Interestingly, the analgesic effect of AS1069562 was sustained for 24 hours after the last administration, although the plasma concentration of AS1069562 was reduced to undetectable levels. In contrast, the analgesic effect of duloxetine did not continue after treatment discontinuation. Discussion: AS1069562 exerts analgesic effects on inflammatory and noninflammatory nociceptive pain in rat models of arthritis pain, and repeated administration of AS1069562 exerts a more persistent analgesic effect on arthritis pain than duloxetine. These findings suggest that AS1069562 has an attractive analgesic profile for the treatment of nociceptive pain. [ABSTRACT FROM AUTHOR]

Objectives: FK1706, a non-immunosuppressive immunophilin ligand, potentiated nerve growth factor- induced neurite outgrowth, putatively mediated via FKBP-52 and the Ras/Raf/MAPK signaling pathway. It also improved mechanical allodynia accompanied by the recovery of intraepidermal nerve fiber density in a painful diabetic neuropathy in rats. The aim of this study was to demonstrate the gene expression profiling in dorsal root ganglion in streptozotocin-induced diabetic rats related to pain and anti-allodynia effects of FK1706 administration to elucidate the putative mechanisms of its neurotrophic activity in vivo. Here, we analyzed gene expression of the dorsal root ganglia using microarray together with behavioral measurement of mechanical allodynia in diabetic rats to try to capture the global fingerprint of changes in gene expression associated with FK1706 administration. Methods: The withdrawal threshold of streptozotocin-induced diabetic rats was measured by an electronic von Frey system. The gene expression of the ganglia from L4 to L6 obtained from streptozotocin-treated rats with or without chronic administration of FK1706 was analyzed using an Affymetrix GeneChip to extract interesting genes in the development of mechanical allodynia in diabetes and anti-allodynia effect of FK1706. Results: Daily oral administration of FK1706 improved mechanical allodynia without decreasing plasma glucose levels. From gene expression analysis, the expression of thioredoxin interacting protein gene was sustained to increased change, whereas those of collagen I alpha1, II alpha1 and IX alpha1 genes were decreased from 2 to 4 weeks after streptozotocin injection. While no changes occurred after 1 week of commencing of FK1706 administration (2 weeks after streptozotocin injection), changes in expression more than 1.5-fold were observed for genes such as Ckm, Actn3, Atp2a1, Bglap, Acta1, Myl1, Tnnc2, and Mylpf at 2 weeks of FK1706 administration (3 weeks after streptozotocin injection). The genes RGD1564519, Hbb, LOC689064, Arpc4 and S100a9 were upregulated in comparison with streptozoto- cin-injected control group at 3 weeks of FK1706 administration; on the other hand, those of Actn3, Atp2a1 were downregulated by FK1706. Discussion: FK1706 ameliorates mechanical allodynia with accompanying increases in gene expressions possibly related to neurite outgrowth, development, differentiation, and nociceptive sensitivity. [ABSTRACT FROM AUTHOR]

The article reports on the study regarding matriptase, a type-II transmembrane serine protease, its structural requirements on ectodomain release in polarized epithelial cells. The study uses monkey kidney, the cell line establishes a tight junctions used as a model of polarized epithelia. The study found that the pos-translational cleavage between Gly149 and Ser150 and the existence of catalytic domain are critical for the ectodomain release of matriptase in stable transfection experiments.

The gamma-aminobutyric acid type B (GABA B) receptor agonist, the sodium salt of gamma-hydroxybutyrate (GHB), significantly improved pain, sleep disturbance and fatigue in fibromyalgia (FM) patients. However, the use of GABA B receptor agonists is limited by their undesirable side-effects. To clarify whether GABA B receptor positive allosteric modulator (PAM) approach would achieve analgesia with less side-effects than GABA B receptor agonist in FM, we investigated the potential of a novel GABA B receptor PAM, ASP8062, for FM treatment. We examined the in vitro profiles of ASP8062, the effects of a GABA B receptor PAM and an agonist on pain in a rat model of FM, and the sleep/wake cycle, EEG during sleep stages and motor coordination in rats. ASP8062 showed PAM activity on human and rat GABA B receptors. Oral administration of ASP8062 significantly reversed the decrease in muscle pressure threshold in reserpine-induced myalgia rats. The analgesic effects of ASP8062 were significantly blocked by a GABA B receptor antagonist. ASP8062 had a significant effect on motor coordination at a 1000-fold higher dose than the analgesic dose in rats. ASP8062 significantly decreased total REM sleep time and frequency of sleep interruptions, and increased the power in delta waves frequency during non-REM sleep in rats. ASP8062, a novel GABA B receptor PAM, has therapeutic potential to exert analgesic effects with less side-effects compared to GABA B receptor agonists in patients with FM. [ABSTRACT FROM AUTHOR]

Abstract: FK1706, a derivative of FK506, is a non-immunosuppressive immunophilin ligand with significant neurotrophic activity mediated via FKBP-52 and the RAS/RAF/MAPK signaling pathway. Here, we tested the effect of FK1706 on painful diabetic neuropathy in rat model of diabetes induced by streptozotocin (STZ). FK1706 ameliorated mechanical allodynia in this model at doses over 0.32mg/kg, p.o., even if treatment was initiated after neuropathy was established, and did not affect plasma glucose levels. Furthermore, this improvement continued at least 4 weeks after the last administration. In morphological analysis, FK1706 treatment also restored intraepidermal nerve fiber density in footpad skin to almost normal levels. Gabapentin also improved mechanical allodynia in the same model, but efficacy disappeared the day after administration stopped. Allodynia responses were potentiated by co-administration of both compounds. Thus, FK1706 ameliorated painful diabetic neuropathy via a different mechanism from gabapentin and improved morphological outcomes, indicating that FK1706 improves painful diabetic neuropathy by modifying the underlying disease pathology. [Copyright &y& Elsevier]

The aim of this study was to clarify the mechanism of disuse-induced muscle hyperalgesia through the evaluation of the pharmacological behaviour of muscle hyperalgesia profiles in chronic post-cast pain (CPCP) rats with acute and chronic-phase mirror-image muscle hyperalgesia treated with diclofenac (NSAID), pregabalin (an inhibitor of Ca 2+ channel α2δ), and duloxetine (SNRI). After 2 weeks of cast immobilization, the peak cross-sectional area and muscle wet weight of the ipsilateral soleus and gastrocnemius muscles decreased more significantly in CPCP rats than in untreated rats. Histological findings revealed disuse-induced muscle atrophy in CPCP rats. The blood biochemical parameters of CPCP rats in acute and chronic phases did not differ significantly from those of untreated rats. The diclofenac and pregabalin-treated groups exhibited no improvement in acute or chronic muscle hyperalgesia. In contrast, the duloxetine-treated group exhibited an improvement in acute muscle hyperalgesia, but showed no apparent effect on chronic muscle hyperalgesia on ipsilateral or contralateral sides. However, the chronic muscle hyperalgesia was reversed by intrathecal administration of DAMGO (a μ-opioid receptor agonist). The results suggest that chronic muscle hyperalgesia in CPCP rats did not result from an inflammatory mechanism, and there is only a low probability that it's caused by a neuropathic mechanism.

AS1069562 [(R)-2-[(1H-inden-7-yloxy)methyl]morpholine monobenzenesulfonate] is the (+)-isomer of indeloxazine, which had been used clinically for the treatment of cerebrovascular diseases with multiple pharmacological actions, including serotonin (5-HT) and norepinephrine (NE) reuptake inhibition. Here we investigated the analgesic effects of AS1069562 in a rat model of chronic constriction injury (CCI)-induced neuropathic pain and the spinal monoamine turnover. These effects were compared with those of the antidepressants duloxetine and amitriptyline. AS1069562 significantly elevated extracellular 5-HT and NE levels in the rat spinal dorsal horn, although its 5-HT and NE reuptake inhibition was much weaker than that of duloxetine in vitro. In addition, AS1069562 increased the ratio of the contents of both 5-HT and NE to their metabolites in rat spinal cord, whereas duloxetine slightly increased only the ratio of the content of 5-HT to its metabolite. In CCI rats, AS1069562 and duloxetine significantly ameliorated mechanical allodynia, whereas amitriptyline did not. AS1069562 and amitriptyline significantly ameliorated thermal hyperalgesia, and duloxetine tended to ameliorate it. Furthermore, AS1069562, duloxetine, and amitriptyline significantly improved spontaneous pain-associated behavior. In a gastric emptying study, AS1069562 affected gastric emptying at the same dose that exerted analgesia in CCI rats. On the other hand, duloxetine and amitriptyline significantly reduced gastric emptying at lower doses than those that exerted analgesic effects. These results indicate that AS1069562 broadly improved various types of neuropathic pain-related behavior in CCI rats with unique characteristics in spinal monoamine turnover, suggesting that AS1069562 may have potential as a treatment option for patients with neuropathic pain, with a different profile from currently available antidepressants.

MT-SP1 (membrane-type serine protease 1)/matriptase is an epithelial-derived integral membrane enzyme. The purpose of the present study was to examine whether the enzyme exists on the basolateral side of simple columnar epithelial cells, such as enterocytes, of normal adult animals. Using COS-1 monkey kidney cells transiently transfected with rat MT-SP1/matriptase expression plasmids, we found that the enzyme is post-translationally processed by the cleavage between Gly149 and Ser150, that a portion of the C-terminal part (Ser150-Val855) remains in the cells by association with the NTF (N-terminal fragment) (Met1-Gly149), while the other portions are released into the medium and that the release is increased on activation by co-expression with hepatocyte growth factor activator inhibitor type-1. Western-blot analysis of crude membranes prepared from rat jejunum demonstrated the presence of the NTF but negligible or no occurrence of the C-terminal part of the protein. Fractionation of the crude membranes by ultracentrifugation with Percoll followed by Western-blot analysis showed that the fractionation profile of the NTF correlated significantly with that of E-cadherin, an adhesion molecule on the lateral membrane. Immunostaining of the jejunum demonstrated the occurrence of the NTF on the lateral membranes but not on the apical membranes. These results suggest that considerable MT-SP1/matriptase molecules occur on the basolateral sides of normal epithelial cells and support our hypothesis that a possible physiological function of this enzyme is the control of epithelial-cell turnover by regulating cell-cell and/or cell-substratum adhesions.

Membrane-type serine protease 1 (MT-SP1), identical to matriptase, is a recently identified type II transmembrane serine protease. MT-SP1/matriptase is of considerable interest for the development, homeostasis, and cancer invasion and metastasis of epithelial tissues. The administration of inhibitors for MT-SP1/matriptase may be effective to suppress the development of tumors where the enzyme may be involved. In the present study, we produced a secreted form of recombinant MT-SP1/matriptase (ekMT-SP1s) that can be activated by enterokinase in vitro and investigated the inhibitory ability of various protease inhibitors toward the recombinant enzyme. The enterokinase-treated ekMT-SP1s (active ekMT-SP1s) cleaved various peptidyl-4-methylcoumaryl-7-amide (MCA) substrates with arginine (or lysine) residue at position P1, and the best substrate was t-butyloxycarbonyl (Boc)-Gln-Ala-Arg-MCA. The specificity for the synthetic and natural substrates of the active ekMT-SP1s was in good agreement with that of the natural enzyme. Endogenous protease inhibitors tested, except for antithrombin III, showed no or little inhibition on the cleavage of Boc-Gln-Ala-Arg-MCA by the active ekMT-SP1s. Aprotinin showed strong inhibitory activity toward the cleavage. Food-derived inhibitors, such as soybean trypsin inhibitor, Bowman-Birk inhibitor, and lima bean trypsin inhibitor inhibited it, while chicken ovomucoid did not. Synthetic inhibitors tested inhibited it, and among them, the inhibitory effect of FOY-305 was strongest. The present findings provide important information for the suppression of cancer invasion and metastasis for which MT-SP1/matriptase is responsible.