NRSF-GNAO1 Pathway Contributes to the Regulation of Cardiac Ca2+ Homeostasis.

BACKGROUND: During the development of heart failure, a fetal cardiac gene program is reactivated and accelerates pathological cardiac remodeling. We previously reported that a transcriptional repressor, NRSF (neuron restrictive silencer factor), suppresses the fetal cardiac gene program, thereby maintaining cardiac integrity. The underlying molecular mechanisms remain to be determined, however. METHODS: We aim to elucidate molecular mechanisms by which NRSF maintains normal cardiac function. We generated cardiac-specific NRSF knockout mice and analyzed cardiac gene expression profiles in those mice and mice cardiac-specifically expressing a dominant-negative NRSF mutant. RESULTS: We found that cardiac expression of Gαo, an inhibitory G protein encoded in humans by GNAO1, is transcriptionally regulated by NRSF and is increased in the ventricles of several mouse models of heart failure. Genetic knockdown of Gnao1 ameliorated the cardiac dysfunction and prolonged survival rates in these mouse heart failure models. Conversely, cardiac-specific overexpression of GNAO1 in mice was sufficient to induce cardiac dysfunction. Mechanistically, we observed that increasing Gαo expression increased surface sarcolemmal L-type Ca2+ channel activity, activated CaMKII (calcium/calmodulin-dependent kinase-II) signaling, and impaired Ca2+ handling in ventricular myocytes, which led to cardiac dysfunction. CONCLUSIONS: These findings shed light on a novel function of Gαo in the regulation of cardiac Ca2+ homeostasis and systolic function and suggest Gαo may be an effective therapeutic target for the treatment of heart failure.

The Inhibition of TREK-1 K+ Channels via Multiple Compounds Contained in the Six Kamikihito Components, Potentially Stimulating Oxytocin Neuron Pathways.

Oxytocin, a significant pleiotropic neuropeptide, regulates psychological stress adaptation and social communication, as well as peripheral actions, such as uterine contraction and milk ejection. Recently, a Japanese Kampo medicine called Kamikihito (KKT) has been reported to stimulate oxytocin neurons to induce oxytocin secretion. Two-pore-domain potassium channels (K2P) regulate the resting potential of excitable cells, and their inhibition results in accelerated depolarization that elicits neuronal and endocrine cell activation. We assessed the effects of KKT and 14 of its components on a specific K2P, the potassium channel subfamily K member 2 (TREK-1), which is predominantly expressed in oxytocin neurons in the central nervous system (CNS). KKT inhibited the activity of TREK-1 induced via the channel activator ML335. Six of the 14 components of KKT inhibited TREK-1 activity. Additionally, we identified that 22 of the 41 compounds in the six components exhibited TREK-1 inhibitory effects. In summary, several compounds included in KKT partially activated oxytocin neurons by inhibiting TREK-1. The pharmacological effects of KKT, including antistress effects, may be partially mediated through the oxytocin pathway.

Therapeutic Potential of Orally Administered Rubiscolin-6.

Rubiscolins are naturally occurring opioid peptides derived from the enzymatic digestion of the ribulose bisphosphate carboxylase/oxygenase protein in spinach leaves. They are classified into two subtypes based on amino acid sequence, namely rubiscolin-5 and rubiscolin-6. In vitro studies have determined rubiscolins as G protein-biased delta-opioid receptor agonists, and in vivo studies have demonstrated that they exert several beneficial effects via the central nervous system. The most unique and attractive advantage of rubiscolin-6 over other oligopeptides is its oral availability. Therefore, it can be considered a promising candidate for the development of a novel and safe drug. In this review, we show the therapeutic potential of rubiscolin-6, mainly focusing on its effects when orally administered based on available evidence. Additionally, we present a hypothesis for the pharmacokinetics of rubiscolin-6, focusing on its absorption in the intestinal tract and ability to cross the blood-brain barrier.

Distinct Profiles of Desensitization of µ-Opioid Receptors Caused by Remifentanil or Fentanyl: In Vitro Assay with Cells and Three-Dimensional Structural Analyses.

Remifentanil (REM) and fentanyl (FEN) are commonly used analgesics that act by activating a µ-opioid receptor (MOR). Although optimal concentrations of REM can be easily maintained during surgery, it is sometimes switched to FEN for optimal pain regulation. However, standards for this switching protocol remain unclear. Opioid anesthetic efficacy is decided in part by MOR desensitization; thus, in this study, we investigated the desensitization profiles of REM and FEN to MOR. The efficacy and potency during the 1st administration of REM or FEN in activating the MOR were almost equal. Similarly, in ß arrestin recruitment, which determines desensitization processes, they showed no significant differences. In contrast, the 2nd administration of FEN resulted in a stronger MOR desensitization potency than that of REM, whereas REM showed a higher internalization potency than FEN. These results suggest that different ß arrestin-mediated signaling caused by FEN or REM led to their distinct desensitization and internalization processes. Our three-dimensional analysis, with in silico binding of REM and FEN to MOR models, highlighted that REM and FEN bound to similar but distinct sites of MOR and led to distinct ß arrestin-mediated profiles, suggesting that distinct binding profiles to MOR may alter ß arrestin activity, which accounts for MOR desensitization and internalization.

Discovery of 7-Azanorbornane-Based Dual Agonists for the Delta and Kappa Opioid Receptors through an In Situ Screening Protocol.

In medicinal chemistry, the copper-catalyzed click reaction is used to prepare ligand candidates. This reaction is so clean that the bioactivities of the products can be determined without purification. Despite the advantages of this in situ screening protocol, the applicability of this method for transmembrane proteins has not been validated due to the incompatibility with copper catalysts. To address this point, we performed ligand screening for the µ, δ, and κ opioid receptors using this protocol. As we had previously reported the 7-azanorbornane skeleton as a privileged scaffold for the G protein-coupled receptors, we performed the click reactions between various 7-substituted 2-ethynyl-7-azanorbornanes and azides. Screening assays were performed without purification using the CellKeyTM system, and the putative hit compounds were re-synthesized and re-evaluated. Although the "hit" compounds for the µ and the δ receptors were totally inactive after purifications, three of the four "hits" for the κ receptor were true agonists for this receptor and also showed activities for the δ receptor. Although false positive/negative results exist as in other screening projects for soluble proteins, this in situ method is effective in identifying novel ligands for transmembrane proteins.

Novel Opioid Analgesics for the Development of Transdermal Opioid Patches That Possess Morphine-Like Pharmacological Profiles Rather Than Fentanyl: Possible Opioid Switching Alternatives Among Patch Formula.

BACKGROUND: Transdermal fentanyl is widely used in the treatment of severe pain because of convenience, safety, and stable blood concentrations. Nevertheless, patients often develop tolerance to fentanyl, necessitating the use of other opioids; transdermal buprenorphine patch is widely used as an analgesic agent, though available formulation does not provide comparable analgesic effect as transdermal fentanyl patch. Opioids bind to the opioid receptor (OR) to activate both G protein-mediated and ß-arrestin-mediated pathways. We synthesized morphine-related compounds with high transdermal absorbability (N1 and N2) and evaluated their OR activities pharmacologically in comparison with fentanyl and morphine. METHODS: In cells stably expressing µ-opioid receptor (MOR), δ-opioid receptor (DOR), and κ-opioid receptor (KOR), G protein-mediated pathways were assessed using the CellKey and an intracellular cyclic adenosine monophosphate (cAMP) assay, while ß-arrestin-mediated pathways were analyzed with ß-arrestin recruitment and receptor internalization assays. Furthermore, analgesic effects were evaluated using a tail-flick test in mice, and the analgesic effect on fentanyl-tolerant mice was evaluated. RESULTS: In the CellKey and cAMP assays, both N1 and N2 showed the highest affinity for MOR and acted as full agonists as well as partial agonists for DOR and KOR. In the ß-arrestin and internalization assays, only fentanyl acted as a full agonist; N1 and N2 acted as partial agonists of MOR. In the mouse tail-flick test, N1 and N2 showed analgesic effects equivalent to those of fentanyl and morphine. In fentanyl-tolerant mice, fentanyl showed a diminished analgesic effect, whereas N1 and N2 as well as morphine retained their analgesic effects. CONCLUSIONS: While N1 and N2 have higher transdermal absorbability than fentanyl, they also have analgesic effects comparable to those of morphine, suggesting that they may be attractive compounds for the development of novel opioid patches for transitioning from fentanyl patches.

Evaluation of the Intracellular Signaling Activities of κ-Opioid Receptor Agonists, Nalfurafine Analogs; Focusing on the Selectivity of G-Protein- and ß-Arrestin-Mediated Pathways.

Opioid receptors (ORs) are classified into three types (µ, δ, and κ), and opioid analgesics are mainly mediated by µOR activation; however, their use is sometimes restricted by unfavorable effects. The selective κOR agonist nalfurafine was initially developed as an analgesic, but its indication was changed because of the narrow safety margin. The activation of ORs mainly induces two intracellular signaling pathways: a G-protein-mediated pathway and a ß-arrestin-mediated pathway. Recently, the expectations for κOR analgesics that selectively activate these pathways have increased; however, the structural properties required for the selectivity of nalfurafine are still unknown. Therefore, we evaluated the partial structures of nalfurafine that are necessary for the selectivity of these two pathways. We assayed the properties of nalfurafine and six nalfurafine analogs (SYKs) using cells stably expressing κORs. The SYKs activated κORs in a concentration-dependent manner with higher EC50 values than nalfurafine. Upon bias factor assessment, only SYK-309 (possessing the 3S-hydroxy group) showed higher selectivity of G-protein-mediated signaling activities than nalfurafine, suggesting the direction of the 3S-hydroxy group may affect the ß-arrestin-mediated pathway. In conclusion, nalfurafine analogs having a 3S-hydroxy group, such as SYK-309, could be considered G-protein-biased κOR agonists.

In Vitro Analyses of Spinach-Derived Opioid Peptides, Rubiscolins: Receptor Selectivity and Intracellular Activities through G Protein- and ß-Arrestin-Mediated Pathways.

Activated opioid receptors transmit internal signals through two major pathways: the G-protein-mediated pathway, which exerts analgesia, and the ß-arrestin-mediated pathway, which leads to unfavorable side effects. Hence, G-protein-biased opioid agonists are preferable as opioid analgesics. Rubiscolins, the spinach-derived naturally occurring opioid peptides, are selective δ opioid receptor agonists, and their p.o. administration exhibits antinociceptive effects. Although the potency and effect of rubiscolins as G-protein-biased molecules are partially confirmed, their in vitro profiles remain unclear. We, therefore, evaluated the properties of rubiscolins, in detail, through several analyses, including the CellKeyTM assay, cADDis® cAMP assay, and PathHunter® ß-arrestin recruitment assay, using cells stably expressing µ, δ, κ, or µ/δ heteromer opioid receptors. In the CellKeyTM assay, rubiscolins showed selective agonistic effects for δ opioid receptor and little agonistic or antagonistic effects for µ and κ opioid receptors. Furthermore, rubiscolins were found to be G-protein-biased δ opioid receptor agonists based on the results obtained in cADDis® cAMP and PathHunter® ß-arrestin recruitment assays. Finally, we found, for the first time, that they are also partially agonistic for the µ/δ dimers. In conclusion, rubiscolins could serve as attractive seeds, as δ opioid receptor-specific agonists, for the development of novel opioid analgesics with reduced side effects.

A novel method for evaluating activity of transient receptor potential channels using a cellular dielectric spectroscopy.

Cellular dielectric spectroscopy (CDS) is a novel technology enabling pharmacological evaluation of multiple receptor types with a label-free cell-based assay. We evaluated activities of a family of ligand-gated channels, transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1) channels by an electrical impedance-based biosensor (CellKey™ system) using CDS. Measures of both potency (EC50) and efficacy (Emax) of these agonists with CellKey™ were almost identical to those made using the traditional Ca2+ influx assay in TRPV1- or TRPA1-expressing cells, suggesting that CellKey™ is a simpler and easier means of evaluating TRP activities.

A novel strategy for treatment of cancer cachexia targeting xanthine oxidase in the brain.

Cancer cachexia is a systemic wasting syndrome characterized by anorexia and loss of body weight. The xanthine oxidase (XO) inhibitor febuxostat is one of the promising candidates for cancer cachexia treatment. However, cachexic symptoms were not alleviated by oral administration of febuxostat in our cancer cachexia model. Metabolomic analysis with brains of our cachexic model showed that purine metabolism was activated and XO activity was increased, and thus suggested that febuxostat would not reach the brain. Accordingly, targeting XO in the brain, which controls appetite, may be an effective strategy for treatment of cancer cachexia.

Possible biased analgesic of hydromorphone through the G protein-over ß-arrestin-mediated pathway: cAMP, CellKey™, and receptor internalization analyses.

Morphine, fentanyl, and oxycodone are widely used as analgesics, and recently hydromorphone has been approved in Japan. Although all of these are selective for µ-opioid receptors (MORs) and have similar structures, their analgesic potencies and adverse effects (AEs) are diverse. Recent molecular analyses of MOR signaling revealed that the G protein-mediated signaling pathway causes analgesic effects and the ß-arrestin-mediated signaling pathway is responsible for AEs. We used several cell-based analyses that selectively measure cellular responses activated by either G protein- or ß-arrestin-mediated pathways. GloSensor™ cAMP, CellKey™, and receptor internalization assays were performed with four different types of cells stably expressing differentially labelled MOR. EC50 values measured by cAMP and CellKey™ assays had potencies in the order fentanyl ≤ hydromorphone < morphine ≤ oxycodone, all also exhibiting full agonist responses. However, in the internalization assay, only fentanyl elicited a full agonist response. Hydromorphone had the strongest potency next to fentanyl; however, contribution of the ß-arrestin-mediated pathway was small, suggesting that its effect could be biased toward the G protein-mediated pathway. Based on these properties, hydromorphone could be chosen as an effective analgesic.

Carboplatin Enhances the Activity of Human Transient Receptor Potential Ankyrin 1 through the Cyclic AMP-Protein Kinase A-A-Kinase Anchoring Protein (AKAP) Pathways.

Carboplatin, an anticancer drug, often causes chemotherapy-induced peripheral neuropathy (PN). Transient receptor potential ankyrin 1 (TRPA1), a non-selective cation channel, is a polymodal nociceptor expressed in sensory neurons. TRPA1 is not only involved in pain transmission, but also in allodynia or hyperalgesia development. However, the effects of TRPA1 on carboplatin-induced PN is unclear. We revealed that carboplatin induced mechanical allodynia and cold hyperalgesia, and the pains observed in carboplatin-induced PN models were significantly suppressed by the TRPA1 antagonist HC-030031 without a change in the level of TRPA1 protein. In cells expressing human TRPA, carboplatin had no effects on changes in intracellular Ca2+ concentration ([Ca2+]i); however, carboplatin pretreatment enhanced the increase in [Ca2+]i induced by the TRPA1 agonist, allyl isothiocyanate (AITC). These effects were suppressed by an inhibitor of protein kinase A (PKA). The PKA activator forskolin enhanced AITC-induced increase in [Ca2+]i and carboplatin itself increased intracellular cyclic adenosine monophosphate (cAMP) levels. Moreover, inhibition of A-kinase anchoring protein (AKAP) significantly decreased the carboplatin-induced enhancement of [Ca2+]i induced by AITC and improved carboplatin-induced mechanical allodynia and cold hyperalgesia. These results suggested that carboplatin induced mechanical allodynia and cold hyperalgesia by increasing sensitivity to TRPA1 via the cAMP-PKA-AKAP pathway.

Cardiotonic actions of quercetin and its metabolite tamarixetin through a digitalis-like enhancement of Ca2+ transients.

The plant-derived flavonoid, quercetin (QCT), has many biological actions, including cardioprotective actions, resulting from its antioxidant and anti-inflammatory effects. In this study, effects of QCT and its metabolites on the contraction and Ca2+ transients (CaT) of mouse single cardiomyocytes were simultaneously measured and compared with those of isoproterenol and digoxin. Furthermore, cardiac function and plasma concentrations were analyzed after bolus intravenous administration of QCT in mice. QCT and its metabolite, tamarixetin, as well as isoproterenol and digoxin, enhanced the contraction and CaT of cardiomyocytes. The inotropic action of isoproterenol was accompanied by an increase in the velocities of sarcomere shortening and relengthening and CaT decay through activation of cAMP-dependent protein kinase; however, no such lusitropic effects accompanied the inotropic action of QCT, tamarixetin or digoxin. Intravenous administration of QCT to mice resulted in a sustained increase in cardiac systolic function; QCT was rapidly metabolized to tamarixetin and its plasma concentration was maintained at high levels over a similar time frame as the enhancement of cardiac systolic function. These results suggest that QCT exerts a cardiotonic action in vivo at least, in part, through digitalis-like enhancement of CaT by itself and its metabolite tamarixetin.

Neuropeptide oxytocin enhances µ opioid receptor signaling as a positive allosteric modulator.

Oxytocin (OT) is a 9-amine neuropeptide that plays an essential role in mammalian labor, lactation, maternal bonding, and social affiliation. OT has been reported to exert an analgesic effect in both humans and animals, and the results of certain animal experiments have shown that the analgesic effect of OT is partially blocked by opioid receptor antagonists. To investigate the relationship between OT and µ opioid receptor (MOR), we evaluated how OT affects MOR in vitro by performing an electrical impedance-based receptor biosensor assay (CellKey™ assay), an intracellular cAMP assay, and a competitive receptor-binding analysis by using cells stably expressing human MOR and OT receptor. In both the CellKey™ assay and the intracellular cAMP assay, OT alone exerted no direct agonistic effect on human MOR, but treatment with 10-6 M OT markedly enhanced the MOR signaling induced by 10-6 M endomorphin-1, ß-endorphin, morphine, fentanyl, and DAMGO. Moreover, in the competitive receptor-binding assay, 10-6 M OT did not alter the affinity of endomorphin-1 or morphine for MOR. These results suggest that OT could function as a positive allosteric modulator that regulates the efficacy of MOR signaling, and thus OT might represent a previously unrecognized candidate analgesic agent.

Usefulness for the combination of G-protein- and ß-arrestin-biased ligands of µ-opioid receptors: Prevention of antinociceptive tolerance.

Background: µ-Opioid receptor internalization is considered to be critically linked to antinociceptive tolerance. Although µ-opioid receptor agonists have been administered simultaneously with other drugs to control pain, little information is available regarding opioid­opioid interactions. Therefore, the present study was designed to further investigate the utility of a new G protein-biased ligand for µ-opioid receptors, TRV130, which has an antinociceptive effect without ß-arrestin-dependent µ-opioid receptor internalization, and its combination with fentanyl using µ-opioid receptor-expressing cells and mice. Results: In the present study, we confirmed that fentanyl produced a profound increase in ß-arrestin-2 recruitment accompanied by µ-opioid receptor internalization, whereas TRV130 did not induce either the recruitment of ß-arrestin-2 or µ-opioid receptor internalization in µ-opioid receptor-expressing cells. Under these conditions, ß-arrestin-2 recruitment accompanied by µ-opioid receptor internalization induced by fentanyl was abolished by TRV130, whereas TRV130 did not alter the reduction of cyclic adenosine monophosphate formation by fentanyl in µ-opioid receptor-expressing cells. In a behavioral assay, TRV130 exerted an antinociceptive effect in a hot-plate test in mice. In a combination test, the antinociceptive effect of TRV130 was synergistically increased by fentanyl. Fentanyl induced antihyperalgesia and development of its tolerance under a neuropathic pain-like state following sciatic nerve ligation. However, treatment of mice with an antinociceptive dose of TRV130 did not induce the rapid development of tolerance to its antihyperalgesic effect under a neuropathic pain-like state. Furthermore, the rapid development of tolerance to the antihyperalgesic effect induced by fentanyl plus TRV130 in mice with sciatic nerve ligation was not observed, unlike in the case of fentanyl alone. Conclusions: These findings provide evidence that activation of the G protein-biased pathway through µ-opioid receptors can alter signaling in the ß-arrestin-2 pathway linked to the stimulation of µ-opioid receptors. Furthermore, the combination of G protein-biased and ß-arrestin-biased ligands of µ-opioid receptors exerts an ideal antinociceptive effect without the rapid development of antinociceptive tolerance.

Therapeutic potential of ghrelin and des-acyl ghrelin against chemotherapy-induced cardiotoxicity.

Cancer was considered an incurable disease for many years; however, with the development of anticancer drugs and state-of-the art technologies, it has become curable. Cardiovascular diseases in patients with cancer or induced by cancer chemotherapy have recently become a great concern. Certain anticancer drugs and molecular targeted therapies cause cardiotoxicity, which limit the widespread implementation of cancer treatment and decrease the quality of life in cancer patients significantly. The anthracycline doxorubicin (DOX) causes cardiotoxicity. The cellular mechanism underlying DOX-induced cardiotoxicity include free-radical damage to cardiac myocytes, leading to mitochondrial injury and subsequent death of myocytes. Recently, circulating orexigenic hormones, ghrelin and des-acyl ghrelin, have been reported to inhibit DOX-induced cardiotoxicity. However, little is known about the molecular mechanisms underlying their preventive effects. In the present study, we show the possible mechanisms underlying the effects of ghrelin and des-acyl ghrelin against DOX-induced cardiotoxicity through in vitro and in vivo researches.

The first structure-activity relationship study of oxytocin as a positive allosteric modulator for the µ opioid receptor.

Positive allosteric modulators (PAMs) of G protein-coupled receptors (GPCRs) have drawn attention as novel drug candidates. PAMs can enhance the activities of endogenous agonists which are not only secreted at appropriate times and in parts of the body, but also are immediately metabolized. Therefore, they are expected to show fewer side effects than exogeneous orthosteric ligands. Recently, we have reported that oxytocin (OT) functioned as a PAM of the µ opioid receptor (MOR) which was one of the most potent targets for analgesics. OT is thus thought to be a useful compound for the development of novel analgesics. In this study, several OT analogs were synthesized and evaluated with an intact cell-based assay to investigate the crucial structures of OT for exerting the PAM activity. The assay results indicated that the cyclic structure formed by an intramolecular disulfide bond and the three C-terminal residues containing a small Gly residue of OT were essential for their function as a MOR-PAM. Intriguingly, two analogs having an amide or an ethylene tether instead of the intramolecular disulfide bridge did not have any PAM effects. The results suggested that the disulfide linkage of OT would be a key structure for exerting the PAM activity at the MOR.

Ketamine Improves Desensitization of µ-Opioid Receptors Induced by Repeated Treatment with Fentanyl but Not with Morphine.

The issue of tolerance to continuous or repeated administration of opioids should be addressed. The ability of ketamine to improve opioid tolerance has been reported in clinical studies, and its mechanism of tolerance may involve improved desensitization of µ-opioid receptors (MORs). We measured changes in MOR activity and intracellular signaling induced by repeated fentanyl and morphine administration and investigated the effects of ketamine on these changes with human embryonic kidney 293 cells expressing MOR using the CellKey™, cADDis cyclic adenosine monophosphate, and PathHunter® ß-arrestin recruitment assays. Repeated administration of fentanyl or morphine suppressed the second MOR responses. Administration of ketamine before a second application of opioids within clinical concentrations improved acute desensitization and enhanced ß-arrestin recruitment elicited by fentanyl but not by morphine. The effects of ketamine on fentanyl were suppressed by co-treatment with an inhibitor of G-protein-coupled receptor kinase (GRK). Ketamine may potentially reduce fentanyl tolerance but not that of morphine through modulation of GRK-mediated pathways, possibly changing the conformational changes of ß-arrestin to MOR.

The Steroidal Alkaloid Tomatidine and Tomatidine-Rich Tomato Leaf Extract Suppress the Human Gastric Cancer-Derived 85As2 Cells In Vitro and In Vivo via Modulation of Interferon-Stimulated Genes.

The steroidal alkaloid tomatidine is an aglycone of α-tomatine, which is abundant in tomato leaves and has several biological activities. Tomatidine has been reported to inhibit the growth of cultured cancer cells in vitro, but its anti-cancer activity in vivo and inhibitory effect against gastric cancer cells remain unknown. We investigated the efficacy of tomatidine using human gastric cancer-derived 85As2 cells and its tumor-bearing mouse model and evaluated the effect of tomatidine-rich tomato leaf extract (TRTLE) obtained from tomato leaves. In the tumor-bearing mouse model, tumor growth was significantly inhibited by feeding a diet containing tomatidine and TRTLE for 3 weeks. Tomatidine and TRTLE also inhibited the proliferation of cultured 85As2 cells. Microarray data of gene expression analysis in mouse tumors revealed that the expression levels of mRNAs belonging to the type I interferon signaling pathway were altered in the mice fed the diet containing tomatidine and TRTLE. Moreover, the knockdown of one of the type I interferon-stimulated genes (ISGs), interferon α-inducible protein 27 (IFI27), inhibited the proliferation of cultured 85As2 cells. This study demonstrates that tomatidine and TRTLE inhibit the tumor growth in vivo and the proliferation of human gastric cancer-derived 85As2 cells in vitro, which could be due to the downregulation of ISG expression.

Intravenous administration of human mesenchymal stem cells derived from adipose tissue and umbilical cord improves neuropathic pain via suppression of neuronal damage and anti-inflammatory actions in rats.

Mesenchymal stem cells (MSCs), which are isolated from adipose tissue (AD-MSCs), umbilical cord (UC-MSCs), or bone marrow, have therapeutic potential including anti-inflammatory and immunomodulatory activities. It was recently reported that MSCs are also effective as a therapeutic treatment for neuropathic pain, although the underlying mechanisms have yet to be resolved. Therefore, in this study, we investigated the effects of human AD- and UC-MSCs on neuropathic pain and its mechanisms using rat models of partial sciatic nerve ligation (PSNL). AD- or UC-MSCs were intravenously administered 4 days after PSNL. Antinociceptive effects were then evaluated using the von Frey and weight-bearing tests. We found that, 3-9 days after the administration of AD- or UC-MSCs to PSNL-exposed rats, both the mechanical threshold and differences in weight-bearing of the right and left hind paws were significantly improved. To reveal the potential underlying antinociceptive mechanisms of MSCs, the levels of activation transcription factor 3- and ionized calcium-binding adapter molecule 1-positive cells were measured by immunohistochemical analysis. AD- and UC-MSCs significantly decreased the levels of these proteins that were induced by PSNL in the dorsal root ganglia. Additionally, UC-MSC significantly improved the PSNL-induced decrease in the myelin basic protein level in the sciatic nerve, indicating that UC-MSC reversed demyelination of the sciatic nerve produced by PSNL. These data suggest that AD- and UC-MSCs may help in the recovery of neuropathic pain via the different regulation; AD-MSCs exhibited their effects via suppressed neuronal damage and anti-inflammatory actions, while UC-MSCs exhibited their effects via suppressed neuronal damage, anti-inflammatory actions and remyelination.