Discovery of 3-amino-4-{(3S)-3-[(2-ethoxyethoxy)methyl]piperidin-1-yl}thieno[2,3-b]pyridine-2-carboxamide (DS96432529): A potent and orally active bone anabolic agent.

The continuing investigation of SAR of 3-aminothieno[2,3-b]pyridine-2-carboxamide derivatives has been described. In this study, C4-piperidine derivatives with polar functional groups were synthesized to develop orally available bone anabolic agents. The optimized compound 9o (DS96432529), which exhibited the best PK profile and high in vitro activity, showed the highest in vivo efficacy in this series. Moreover, significant synergistic effects were observed following co-administration of DS96432529 and alendronate or parathyroid hormone. The mechanism of action is most likely mediated through CDK8 inhibition.

Synthesis and structure-activity relationship of 4-alkoxy-thieno[2,3-b]pyridine derivatives as potent alkaline phosphatase enhancers for osteoporosis treatment.

The synthesis and structure-activity relationships of a novel series of 3-aminothieno[2,3-b]pyridine-2-carboxamides were explored. Our efforts were focused on modifying the C-4 substituent of the thienopyridine ring to develop orally available bone anabolic agents. 4-Alkoxy derivatives were found to be novel ALPase enhancers without inhibitory effect on P450 activity. Among these derivatives, compound 6k was orally administered to ovariectomized rats, and it was found to significantly improve areal bone mineral density at a dose of 30 mg/kg/day.

MicroRNA Profiling Reveals Marker of Motor Neuron Disease in ALS Models.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder marked by the loss of motor neurons (MNs) in the brain and spinal cord, leading to fatally debilitating weakness. Because this disease predominantly affects MNs, we aimed to characterize the distinct expression profile of that cell type to elucidate underlying disease mechanisms and to identify novel targets that inform on MN health during ALS disease time course. microRNAs (miRNAs) are short, noncoding RNAs that can shape the expression profile of a cell and thus often exhibit cell-type-enriched expression. To determine MN-enriched miRNA expression, we used Cre recombinase-dependent miRNA tagging and affinity purification in mice. By defining the in vivo miRNA expression of MNs, all neurons, astrocytes, and microglia, we then focused on MN-enriched miRNAs via a comparative analysis and found that they may functionally distinguish MNs postnatally from other spinal neurons. Characterizing the levels of the MN-enriched miRNAs in CSF harvested from ALS models of MN disease demonstrated that one miRNA (miR-218) tracked with MN loss and was responsive to an ALS therapy in rodent models. Therefore, we have used cellular expression profiling tools to define the distinct miRNA expression of MNs, which is likely to enrich future studies of MN disease. This approach enabled the development of a novel, drug-responsive marker of MN disease in ALS rodents.SIGNIFICANCE STATEMENT Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which motor neurons (MNs) in the brain and spinal cord are selectively lost. To develop tools to aid in our understanding of the distinct expression profiles of MNs and, ultimately, to monitor MN disease progression, we identified small regulatory microRNAs (miRNAs) that were highly enriched or exclusive in MNs. The signal for one of these MN-enriched miRNAs is detectable in spinal tap biofluid from an ALS rat model, where its levels change as disease progresses, suggesting that it may be a clinically useful marker of disease status. Furthermore, rats treated with ALS therapy have restored expression of this MN RNA marker, making it an MN-specific and drug-responsive marker for ALS rodents.

Suppression of allergic inflammation by the prostaglandin E receptor subtype EP3.

Prostaglandins, including PGD(2) and PGE(2), are produced during allergic reactions. Although PGD(2) is an important mediator of allergic responses, aspirin-like drugs that inhibit prostaglandin synthesis are generally ineffective in allergic disorders, suggesting that another prostaglandin-mediated pathway prevents the development of allergic reactions. Here we show that such a pathway may be mediated by PGE(2) acting at the prostaglandin E receptor EP3. Mice lacking EP3 developed allergic inflammation that was much more pronounced than that in wild-type mice or mice deficient in other prostaglandin E receptor subtypes. Conversely, an EP3-selective agonist suppressed the inflammation. This suppression was effective when the agonist was administered 3 h after antigen challenge and was associated with inhibition of allergy-related gene expression. Thus, the PGE(2)-EP3 pathway is an important negative modulator of allergic reactions.

Pathogenic importance of intestinal hypermotility in NSAID-induced small intestinal damage in rats.

BACKGROUND/AIM: Nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin produce damage in the small intestine as a major adverse reaction. We examined the effect of various NSAIDs on intestinal motility and investigated the pathogenic importance of motility changes in the intestinal ulcerogenic response to indomethacin in rats. METHODS: Animals without fasting were given various NSAIDs (indomethacin 10 mg/kg, diclofenac 40 mg/kg, flurbiprofen 20 mg/kg, naproxen 40 mg/kg) s.c., and in the case of indomethacin, the following parameters were examined in the small intestine 24 h later; the lesion score, the number of enterobacteria and myeloperoxidase (MPO) as well as inducible nitric oxide (iNOS) activity. Intestinal motility was monitored as intraluminal pressure recordings using a balloon under anesthesia. RESULTS: All NSAIDs tested decreased mucosal PGE(2) levels and produced hemorrhagic lesions in the small intestine, accompanied by intestinal hypermotility. As representative of NSAIDs, indomethacin also increased the extent of enterobacterial invasion and MPO as well as iNOS activity before the occurrence of intestinal damage, and the hypermotility response was observed earlier than the onset of any other event caused by this agent. The intestinal lesions induced by indomethacin were prevented by either supplementation with dmPGE(2), inhibition of bacterial invasion with ampicillin or inhibition of iNOS activity with aminoguanidine, while the hypermotility response was prevented by dmPGE(2) only. In addition, the observed effects of dmPGE(2) were all mimicked by atropine when the intestinal hypermotility was suppressed by this agent. CONCLUSION: These results suggest the pathogenic importance of intestinal hypermotility in the intestinal ulcerogenic response to NSAIDs in rats and show that this event is critical for the occurrence of enterobacterial invasion under PG deficiency, followed by various inflammatory changes and damage in the mucosa. This study also suggests that the antispasmodic drug is protective against NSAID-induced intestinal lesions.

16,16-Dimethyl prostaglandin E2 inhibits indomethacin-induced small intestinal lesions through EP3 and EP4 receptors.

We evaluated the effect of various PGE analogs specific to EP receptor subtypes on indomethacin-induced small intestinal lesions in rats and investigated the relationship of EP receptor subtype with the PGE action using EP receptor knockout mice. Animals were administered indomethacin subcutaneously, and they were killed 24 hr later. 16,16-dimethyl prostaglandin E2 (dmPGE2) or various EP agonists were administered intravenously 10 min before indomethacin. Indomethacin caused hemorrhagic lesions in the rat small intestine, accompanied with an increase in intestinal motility and the number of enteric bacteria as well as iNOS and MPO activities. Prior administration of dmPGE2 dose-dependently prevented intestinal lesions, together with inhibition of those functional changes. These effects of dmPGE2 were mimicked by prostanoids (ONO-NT-012 and ONO-AE1-329), only specific to EP3 or EP4 receptors, although the intestinal motility was inhibited only by ONO-AE1-329. Intestinal mucus secretion and fluid accumulation were decreased by indomethacin but enhanced by dmPGE2, ONO-NT-012, and ONO-AE1-329 at the doses that prevented intestinal lesions. Indomethacin also caused intestinal lesions in both wild-type and knockout mice lacking EP1 or EP3 receptors, yet the protective action of dmPGE2 was observed in wild-type and EP1 receptor knockout mice but not the mice lacking EP3 receptors. These results suggest that the intestinal cytoprotective action of PGE2 against indomethacin is mediated by EP3/EP4 receptors and that this effect is functionally associated with an increase of mucus secretion and enteropooling as well as inhibition of intestinal hypermotility, the former two processes mediated by both EP3 and EP4 receptors, and the latter by EP4 receptors.

Protective effect of thiaton, an antispasmodic drug, against indomethacin-induced intestinal damage in rats.

The effect of thiaton [3-(di-2-thienylmethylene)-5-methyl-trans-quinolizidinium bromide], an antispasmodic drug, on indomethacin-induced intestinal damage was examined in rats. The animals were given indomethacin, s.c., and the intestinal mucosa was examined 24 h later. Thiaton or atropine was given s.c. twice, 30 min before and 8 h following indomethacin. Indomethacin caused intestinal damage, accompanied with increase in enterobacterial translocation as well as inducible nitric oxide synthase (iNOS) and myeloperoxidase (MPO) activities, and these changes were significantly prevented by supplementation with 16,16-dimethyl prostaglandin E2 (dmPGE2). Treatment of the animals with thiaton dose-dependently prevented the intestinal damage, together with the suppression of MPO and iNOS activities, and these effects were similarly observed by atropine. The increase of bacterial translocation was also significantly prevented by both thiaton and atropine, similar to dmPGE2. Indomethacin enhanced intestinal motility, and this effect was inhibited by either thiaton, atropine or dmPGE2. The intestinal mucus and fluid secretions were decreased by indomethacin but enhanced by dmPGE2. Both thiaton and atropine slightly decreased these secretions under basal conditions but significantly reversed the decrease in the secretions caused by indomethacin. These results suggest that thiaton protects the small intestine against indomethacin-induced damage and inflammatory changes, and this effect is related with prevention of enterobacterial translocation, the process being associated with inhibition of intestinal hypermotility caused by indomethacin, probably due to anti-muscarinic action.