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Introduction We investigated the mechanisms of the glucose-lowering effects of teneligliptin and canagliflozin, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, by monitoring several gastrointestinal peptides using the most appropriate measuring methods during multiple meal tolerance tests (MTTs) and flash glucose monitoring. Methods Twelve Japanese patients with type 2 diabetes were enrolled in the 14-day study. Subjects were treated with teneligliptin 20 mg/day from day 4, followed by a combination tablet of teneligliptin 20 mg and canagliflozin 100 mg (T/C) per day from day 11. MTTs were conducted on days 3 (premedication; Pre), 10 (teneligliptin; T) and 13 (T/C) to evaluate plasma glucose, C-peptide, glucagon, active glucagon-like peptide-1 (GLP-1), active gastric inhibitory polypeptide (GIP), ghrelin and des-acyl ghrelin. Results Plasma glucose was significantly decreased with the progress of treatment intervention, and C-peptide was significantly decreased in T/C compared to the others. Plasma postprandial glucagon was increased for 90 min from fasting in Pre, but only for 30 min in T and T/C. Plasma postprandial active GLP-1 was significantly increased in T compared to Pre, and that of T/C was significantly higher than T. Plasma postprandial active GIP was increased in T and T/C compared to Pre. Plasma ghrelin and des-acyl ghrelin levels did not change during the treatment. Conclusion Teneligliptin increased incretin hormones and suppressed postprandial glucagon secretion as expected. Concurrent use of canagliflozin and teneligliptin improved glycemic control without increasing postprandial glucagon secretion, and increased postprandial GLP-1 secretion and decreased the required amount of postprandial insulin secretion. The underlying mechanisms may involve canagliflozin’s inhibitory activity against not only SGLT2 but also SGLT1. Trial Registration UMIN identifier, UMIN000030043. Funding Mitsubishi Tanabe Pharma Corporation and a Grant for Clinical Research from Miyazaki University Hospital. Electronic supplementary material The online version of this article (10.1007/s13300-019-0666-7) contains supplementary material, which is available to authorized users.

Engagement of the BCR with Ags triggers signaling pathways for commitment of B lymphocyte responses that can be regulated, in part, by reactive oxygen species. To investigate the functional relevance of reactive oxygen species produced in primary B cells, we focused on the role of the hydrogen peroxide generator Duox1 in stimulated splenic B cells under the influence of the TH2 cytokine IL-4. We found that H2O2 production in wild type (WT) and Nox2-deficient CD19+ B cells was boosted concomitantly with enhanced expression of Duox1 following costimulation with BCR agonists together with IL-4, whereas stimulated Duox1−/− cells showed attenuated H2O2 release. We examined whether Duox1-derived H2O2 contributes to proliferative activity and Ig isotype production in CD19+ cells upon BCR stimulation. Duox1−/− CD19+ B cells showed normal responses of Ig production but a higher rate of proliferation than WT or Nox2-deficient cells. Furthermore, we demonstrated that the H2O2 scavenger catalase mimics the effect of Duox1 deficiency by enhancing proliferation of WT CD19+ B cells in vitro. Results from immunized mice reflected the in vitro observations: T cell–independent Ag induced increased B cell expansion in germinal centers from Duox1−/− mice relative to WT and Nox2−/− mice, whereas immunization with T cell–dependent or –independent Ag elicited normal Ig isotype secretion in the Duox1 mutant mice. These observations, obtained both by in vitro and in vivo approaches, strongly suggest that Duox1-derived hydrogen peroxide negatively regulates proliferative activity but not Ig isotype production in primary splenic CD19+ B cells.

Hermansky-Pudlak syndrome (HPS) encompasses disorders with abnormal function of lysosomes and lysosome-related organelles, and some patients who develop immunodeficiency. The basic mechanisms contributing to immune dysfunction in HPS are ill-defined. We analysed Natural Killer (NK) cells from patients diagnosed with HPS-1, HPS-2, HPS-4, and an unreported HPS subtype. NK cells from an HPS-2 and an unreported HPS subtype share a similar cellular phenotype with defective granule release and cytotoxicity, but differ in cytokine exocytosis. Defining NK cell activity in several types of HPS provides insights into cellular defects of the disorder and understanding of mechanisms contributing to HPS pathogenesis.

Homeostasis requires the immunologically silent clearance of apoptotic cells before they become pro-inflammatory necrotic cells. CD300f (CLM-1) is a phosphatidylserine receptor known to positively regulate efferocytosis by macrophages, and CD300f gene-deficient mice are predisposed to develop a lupus-like disease. Here we show that, in contrast to CD300f function in macrophages, its expression inhibits efferocytosis by DC, and its deficiency leads to enhanced antigen processing and T-cell priming by these DC. The consequences are the expansion of memory T cells and increased ANA levels in aged CD300f-deficient mice, which predispose CD300f-deficient mice to develop an overt autoimmune disease when exposed to an overload of apoptotic cells, or an exacerbated autoimmunity when combined with FcγRIIB deficiency. Thus, our data demonstrates that CD300f helps to maintain immune homeostasis by promoting macrophage clearance of self-antigens, while conversely inhibiting DC uptake and presentation of self-antigens.

FcR specific for pentameric IgM (FCMR) is expressed at high levels by B cells. Although circulating IgM has profound effects on responses to pathogens, autoimmunity, and B cell homeostasis, the biologic consequences of its binding to FCMR are poorly understood. We interrogated FCMR contributions to B cell function by studying mice that lack FCMR. FCMR transcripts are expressed at different levels by various B cell subsets. FCMR-deficient mice have reduced numbers of developing B cells, splenic follicular and peritoneal B-2 cells, but increased levels of peritoneal B-1a cells and autoantibodies. After immunization, germinal center B cell and plasma cell numbers are increased. FCMR-deficient B cells are sensitive to apoptosis induced by BCR ligation. Our studies demonstrate that FCMR is required for B cell differentiation and homeostasis, the prevention of autoreactive B cells, and responsiveness to antigenic challenge.

The present study describes the isolation, cloning and characterization of adipogenic progenitor cells from rat skeletal muscle. Among the obtained 10 clones, the most highly adipogenic progenitor, 2G11 cells, were further characterized. In addition to their adipogenicity, 2G11 cells retain myogenic potential as revealed by formation of multinucleated myotubes when co-cultured with myoblasts. 2G11 cells were resistant to an inhibitory effect of basic fibroblast growth factor on adipogenesis, while adipogenesis of widely used preadipogenic cell line, 3T3-L1 cells, was suppressed almost completely by the same treatment. In vivo transplantation experiments revealed that 2G11 cells are able to possess both adipogenicity and myogenicity in vivo. These results indicate the presence of bipotent progenitor cells in rat skeletal muscle, and suggest that such cells may contribute to ectopic fat formation in skeletal muscle.

Objective Triggering receptor expressed on myeloid cells 1 (TREM-1) is inducible on monocyte/macrophages and neutrophils and accelerates tissue destruction by propagating inflammatory responses in disease related to bacterial infections. Its blockade rescues the hosts in murine models of sepsis, to clear the bacteria without impairing the host defense. The aim of this study was to investigate the involvement of TREM-1 in an autoimmune, noninfectious disease. Methods Synovial tissue specimens from the joints of patients with rheumatoid arthritis (RA) and the joints of mice with collagen-induced arthritis (CIA) were examined for TREM-1 expression, using flow cytometric analysis. Expression of TREM-1 on macrophages was induced by lipopolysaccharide, with or without a cyclooxygenase inhibitor. Rheumatoid synovial cells were stimulated with agonistic anti–TREM-1 antibodies. Recombinant adenovirus encoding the extracellular domain of TREM-1 fused with IgG-Fc (AxCATREM-1 Ig) or synthetic TREM-1 antagonistic peptides were injected to treat CIA, and the clinical manifestations of the antigen-specific T cell and B cell responses were evaluated. Results TREM-1 was expressed on CD14+ cells in rheumatoid synovial tissue and synovial macrophages from mice with CIA. Unlike murine macrophages, human monocyte/macrophages did not depend on prostaglandin E2 for up-regulation of TREM-1. Agonistic anti–TREM-1 antibodies promoted tumor necrosis factor α production from rheumatoid synovial cells. Blockade of TREM-1 using AxCATREM-1 Ig and antagonistic peptides ameliorated CIA without affecting the serum levels of anti–type II collagen antibodies or the proliferative responses of splenocytes to type II collagen. Conclusion TREM-1 ligation contributes to the pathology of autoimmune arthritis. The results of this study implied that blockade of TREM-1 could be a new approach to rheumatic diseases that is safer than the presently available immunosuppressive treatments.

Satellite cells are skeletal muscle progenitor/stem cells that reside between the basal lamina and plasma membranes of skeletal muscle fibers in vivo and can give rise to both myogenic and adipogenic cells. The isolated skeletal muscle single fiber culture is an in vitro model that has the advantage of enabling the researcher to monitor the differentiation of satellite cells in a closer microenvironment found in living muscle in vivo. The aim of the present study was to establish single fiber culture of goat skeletal muscle and monitor satellite cell differentiation in this system. Fine single fibers were isolated from goat intercostal muscle by enzymatic treatment, and satellite cells on the fibers were analyzed immunocytochemically. Satellite cells on freshly isolated fibers were positive for Pax7, but negative for MyoD and myogenin, indicating that they are quiescent. As the culture period progressed, the satellite cells became positive for myogenic markers MyoD and myogenin. The satellite cells that detached from the fiber and migrated onto the culture dish were positive for both MyoD and myogenin, and some of them formed multinucleated myosin heavy chain-positive myotubes. In addition, hypercontraction of isolated fine fibers induced adipogenic differentiation of satellite cells. The present study is the first to describe establishment of a goat skeletal muscle single fiber culture that can be used as a model system for further studies on satellite cell behavior in ruminants.

The mouse IGF-I gene contains six exons, and exon 1 and exon 2 gene are considered to be leader exons. The regulatory mechanism of alternative usage of the leader exons is unclear in mice. The present study, was aimed at clarifying changes in class 1 (derived from exon 1) and class 2 (derived from exon 2) IGF-I mRNA expression in mice under various conditions. Both class 1 and class 2 IGF-I mRNAs were expressed in the mouse uterus, liver and kidney, and class 1 IGF-I mRNA was the major transcript in all organs studied. In the uterus, both class 1 and class 2 IGF-I mRNA expression changed markedly during the estrous cycle, with the highest level at proestrus, but in the liver and kidney there were no significant changes in IGF-I mRNA expression during the estrous cycle. Estrogen treatment increased both class 1 and class 2 IGF-I mRNA levels in the uterus of ovariectomized mice, but class 1 mRNA expression increased more in response to estrogen treatment than class 2 mRNA expression. These findings suggest that estrogen stimulates IGF-I gene expression in, uterine cells, and that a promoter involved in transcription of class 1 IGF-I mRNA is more responsive to estrogen. In conclusion, the present study revealed that two leader exons of mouse IGF-I gene are used in the uterus, liver and kidney. IGF-I mRNA levels of both classes changed during the estrous cycle in the uterus, but not in the liver or kidney. Estrogen increased IGF-I mRNA levels of both classes in the uterus.

Triggering receptor expressed on myeloid cells-1 (TREM-1) is a recently identified cell surface molecule that is expressed by neutrophils and monocytes. TREM-1 expression is modulated by various ligands for TLRs in vitro and in vivo. However, the influence of PGE2, a potential mediator of inflammation, on TREM-1 expression has not been elucidated. In this study, we examined the effects of PGE2 on LPS-induced TREM-1 expression by resident murine peritoneal macrophages (RPM) and human PBMC. PGE2 significantly induced murine TREM-1 (mTREM-1) expression by RPM. Up-regulation of TREM-1 expression was specific to PGE2 among arachidonic acid metabolites, while ligands for chemoattractant receptor-homologous molecule expressed on Th2 cells and the thomboxane-like prostanoid receptor failed to induce mTREM-1 expression. PGE2 also increased expression of the soluble form of TREM-1 by PBMC. LPS-induced TREM-1 expression was regulated by endogenous PGE2 especially in late phase (>2 h after stimulation), because cyclooxygenase-1 and -2 inhibitors abolished this effect at that points. A synthetic EP4 agonist and 8-Br-cAMP also enhanced mTREM-1 expression by RPM. Furthermore, protein kinase A, PI3K, and p38 MAPK inhibitors prevented PGE2-induced mTREM-1 expression by RPM. Activation of TREM-1 expressed on PGE2-pretreated PBMC by an agonistic TREM-1 mAb significantly enhanced the production of IL-8 and TNF-α. These findings indicate that LPS-induced TREM-1 expression on macrophages is mediated, at least partly, by endogenous PGE2 followed by EP4 and cAMP, protein kinase A, p38 MAPK, and PI3K-mediated signaling. Regulation of TREM-1 and the soluble form of TREM-1 expression by PGE2 may modulate the inflammatory response to microbial pathogens.

The aims of the present study were to establish a culture system for goat skeletal muscle stem cells and to examine their myogenic and adipogenic properties in vitro. Cells were isolated from the skeletal muscle of the Shiba goat and cultured in vitro. Most of the cells were positive for myogenic markers, such as Pax7, MyoD, and desmin, and immunocytochemistry revealed they differentiated to form myotubes expressing myosin heavy chain, indicating they were highly myogenic. Myogenic differentiation was strongly suppressed by the addition of basic fibroblast growth factor, while proliferation was unaffected. When the cells were cultured in adipogenic differentiation medium, some of the cells differentiated into mature adipocytes that stained with Oil Red-O. These cells were immunocytochemically positive for adipogenic markers, including peroxisome proliferator-activated receptor-gamma (PPAR gamma) and CCAAT/enhancer-binding protein-alpha (C/EBP alpha). These results clearly demonstrate the presence of both myogenic and adipogenic stem cells in goat skeletal muscle.

Interleukin-18 (IL-18) is a proinflammatory cytokine involved in chronic inflammation, autoimmune diseases, and a variety of cancers, and is expressed in mouse uteri. Our previous study suggested that IL-18 acts as a paracrine factor, regulating endometrial function. To elucidate the physiological roles of IL-18 in the mouse endometrium, the expression of the IL-18 receptor (IL-18R) alpha subunit was analyzed. IL-18Ralpha mRNA was expressed in several mouse organs in addition to the endometrium. In situ hybridization analysis using a biotin-labeled mouse IL-18Ralpha riboprobe demonstrated that IL-18Ralpha mRNA expression was detected in glandular epithelial cells, stromal cells around uterine glands, and myometrial cells in the mouse uterus, suggesting that these cells are targets for IL-18. The uterine IL-18Ralpha mRNA expression level changed with the estrous cycle. The uterine IL-18Ralpha mRNA levels of estrous mice were higher than those of diestrous mice. In addition, the IL-18Ralpha mRNA levels in uteri at 3 and 14 days after ovariectomy were higher than those at diestrus and decreased following treatment with estradiol-17beta or progesterone. These findings suggest that IL-18Ralpha gene expression is regulated by estrogen and progesterone and that the uterine IL-18 system is involved in the regulation of uterine functions in a paracrine manner.

Engulfment of apoptotic cells is predominantly executed by phagocytes via the recognition of “eat me” signals like phosphatidylserine (PS). Various PS-specific receptors exist on phagocytes, including Tyro3, Axl, and MerTK receptor tyrosine kinases (TAMs), T-cell immunoglobulin and mucin domain containing 1 and 4 (TIM1/4), and the newly identified CD300 family. The aim of the present auto-commentary is to highlight recent findings regarding the Cd300lf and Cd300lb receptors and their emerging roles in the development of autoimmune disease.

Background Mutations in lysosomal trafficking regulator (LYST) cause Chediak-Higashi syndrome (CHS), a rare immunodeficiency with impaired cytotoxic lymphocyte function, mainly that of natural killer (NK) cells. Our understanding of NK cell function deficiency in patients with CHS and how LYST regulates lytic granule exocytosis is very limited. Objective We sought to delineate cellular defects associated with LYST mutations responsible for the impaired NK cell function seen in patients with CHS. Methods We analyzed NK cells from patients with CHS with missense mutations in the LYST ARM/HEAT (armadillo/huntingtin, elongation factor 3, protein phosphatase 2A, and the yeast kinase TOR1) or BEACH (beige and Chediak-Higashi) domains. Results NK cells from patients with CHS displayed severely reduced cytotoxicity. Mutations in the ARM/HEAT domain led to a reduced number of perforin-containing granules, which were significantly increased in size but able to polarize to the immunologic synapse; however, they were unable to properly fuse with the plasma membrane. Mutations in the BEACH domain resulted in formation of normal or slightly enlarged granules that had markedly impaired polarization to the IS but could be exocytosed on reaching the immunologic synapse. Perforin-containing granules in NK cells from patients with CHS did not acquire certain lysosomal markers (lysosome-associated membrane protein 1/2) but were positive for markers of transport vesicles (cation-independent mannose 6-phosphate receptor), late endosomes (Ras-associated binding protein 27a), and, to some extent, early endosomes (early endosome antigen 1), indicating a lack of integrity in the endolysosomal compartments. NK cells from patients with CHS had normal cytokine compartments and cytokine secretion. Conclusion LYST is involved in regulation of multiple aspects of NK cell lytic activity, ranging from governance of lytic granule size to control of their polarization and exocytosis, as well as regulation of endolysosomal compartment identity. LYST functions in the regulated exocytosis but not in the constitutive secretion pathway.

Insulin-like growth factor-I (IGF-I) gene generates several IGF-I mRNA variants by alternative splicing. Two promoters are present in mouse IGF-I gene. Each promoter encodes two IGF-I mRNA variants (IGF-IA and IGF-IB mRNAs). Variants differ by the presence (IGF-IB) or absence (IGF-IA) of a 52-bp insert in the E domain-coding region. Functional differences among IGF-I mRNAs, and regulatory mechanisms for alternative splicing of IGF-I mRNA are not yet known. We analyzed the expression of mouse IGF-IA and IGF-IB mRNAs using SYBR Green real-time RT-PCR. In the liver, IGF-I mRNA expression increased from 10 days of age to 45 days. In the uterus and ovary, IGF-I mRNA expression increased from 21 days of age, and then decreased at 45 days. In the kidney, IGF-I mRNA expression decreased from 10 days of age. IGF-IA mRNA levels were higher than IGF-IB mRNA levels in all organs examined. Estradiol-17 beta (E2) treatment in ovariectomized mice increased uterine IGF-IA and IGF-IB mRNA levels from 3 hr after injection, and highest levels for both mRNAs were detected at 6 hr, and relative increase was greater for IGF-IB mRNA than for IGF-IA mRNA. These results suggest that expression of IGF-I mRNA variants is regulated in organ-specific and age-dependent manners, and estrogen is involved in the change of IGF-I mRNA variant expression.

Lipoxins (LXs) are members of eicosanoid family that can be endogenously produced during cell-to-cell interactions such as platelet-leukocyte interactions. Anti-inflammatory function of lipoxin A4 (LXA4) as "braking signals" is mediated by the receptor. On the other hand, thromboxane A2 (TXA2) produced by catalysis of cyclooxygenase and thromboxane synthetase is released during platelet aggregation as a vasoconstrictor and a pro-inflammatory factor. To investigate interaction of TXA2 receptor (TP) and LXA4 receptor, effects of a TP agonist and a thromboxane synthetase inhibitor on expression of LXA4 receptor were examined in vitro and in vivo. A TP agonist, U46619 showed a down-regulation of LXA4 receptor induced by interleukin-1beta (IL-1beta) in RAW246.7 cells. In bleomycin-induced lung fibrosis in mice, administration of a thromboxane synthetase inhibitor DP-1904 increased LXA4 receptor mRNA and decreased type I collagen mRNA. In vitro experiments indicate that LXA4 significantly prevented enhanced proliferation of NIH3T3 fibroblasts and the collagen expression by transforming growth factor-beta (TGF-beta). These results suggest that TXA2-TP signaling could cause negative regulation of lipoxin A4 receptor under the transcriptional level during inflammatory process mediated by IL-1beta and TGF-beta induce the expression of LXA4 receptor. Furthermore, the down-regulation of LXA4 receptor by TXA2 implies a possibility that a cellular signaling by TXA2 may have a novel and potential function as a pro-inflammatory factor to inhibit anti-inflammatory effect of LXA4. Concomitantly, selective blockade of TXA2-TP signaling could be suggested to lead to anti-inflammation through active role of LXA4.

Objective Hematopoietic prostaglandin D synthase (H-PGDS) is a key enzyme in the production of prostaglandin D and its J series metabolites. We evaluated the antiinflammatory effect of retrovirally transfected H-PGDS in order to investigate the role of H-PGDS in monosodium urate monohydrate (MSU) crystal–induced acute inflammation. Methods Expression of endogenous PGDS in a murine air-pouch model of MSU crystal–induced acute inflammation was determined by real-time polymerase chain reaction. H-PGDS complementary DNA (cDNA) was retrovirally transfected into C57BL/6J fibroblasts, and the cells were designated as C57-PGDS cells. Production of prostaglandins by C57-PGDS cells was measured by enzyme immunoassay. The effect of C57-PGDS cells on crystal-induced inflammation was investigated. Results Injection of the crystals caused a rapid decrease in H-PGDS expression by infiltrating cells and by the soft tissues around the air pouches. In contrast, expression of interleukin-1β (IL-1β) and macrophage inflammatory protein 2 (MIP-2) as well as cellular infiltration were significantly increased during the early stage of inflammation. C57-PGDS cells, but not control cells, produced an increased amount of PGD2 in vitro, but suppressed production of PGE2. Injection of C57-PGDS cells into air pouches inhibited cellular infiltration and MIP-2 and IL-1β expression. Conclusion In this murine air-pouch model of MSU crystal–induced inflammation, retrovirally transfected H-PGDS cDNA could reduce cellular infiltration, at least partly by inhibiting MIP-2 and IL-1β. These findings suggest that gene therapy with H-PGDS may be useful for treating inflammatory diseases.

High-quality single-walled carbon nanotubes (SWNTs) were obtained from arc-produced soot using a three-step purification process consisting of soft oxidation, air oxidation, and a high-temperature vacuum treatment. Firstly an oxide layer was formed on the surface of the metal catalyst, which prevents the SWNTs from undergoing metal-assisted dissociation during the process. After the final step, about 20% of the weight of the initial raw soot remained and the final product contained less than 1% metal. Scanning electron microscopy, transmission electron microscopy and Raman spectroscopy were used to characterize the SWNTs obtained.

Objective: To study the role of the Ras/mitogen-activated protein kinase (MAPK) pathway in the proliferative response of rheumatoid synovial fibroblast (RSF) to tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-α.¶Methods: V-Ki-ras gene was introduced into RSF using a retrovirus and the proliferative response of these cells to TNF-α or TGF-α was estimated by measuring the uptake of 3H-thymidine. The effect of a mitogen-activated protein kinase kinase (MEK) inhibitor, PD98059, was also investigated.¶Results: Consistent with previous reports, TNF-α and TGF-α stimulated the proliferation of RSF. When the v-Ki-ras gene was expressed, the basal growth rate of these cells was increased, but their growth was suppressed by TNF-α or TGF-α. The latter effect was abolished when the cells were exposed to a relatively low concentration of PD98059.¶Conclusion: Ras modulates the proliferative response of RSF to TNF-α and TGF-α.

Apoptotic cell (AC) clearance is essential for immune homeostasis. Here we show that mouse CD300f (CLM-1) recognizes outer membrane-exposed phosphatidylserine, and regulates the phagocytosis of ACs. CD300f accumulates in phagocytic cups at AC contact sites. Phosphorylation within CD300f cytoplasmic tail tyrosine-based motifs initiates signals that positively or negatively regulate AC phagocytosis. Y276 phosphorylation is necessary for enhanced CD300f-mediated phagocytosis through the recruitment of the p85α regulatory subunit of phosphatidylinositol-3-kinase (PI3K). CD300f-PI3K association leads to activation of downstream Rac/Cdc42 GTPase and mediates changes of F-actin that drive AC engulfment. Importantly, primary macrophages from CD300f-deficient mice have impaired phagocytosis of ACs. The biological consequence of CD300f deficiency is predisposition to autoimmune disease development, as FcγRIIB-deficient mice develop a systemic lupus erythematosus-like disease at a markedly accelerated rate if CD300f is absent. In this report we identify the mechanism and role of CD300f in AC phagocytosis and maintenance of immune homeostasis.

Induction of cyclin-dependent kinase (CDK) inhibitor gene p16INK4a into the synovial tissues suppresses rheumatoid arthritis in animal models. In vitro studies have shown that the cell-cycle inhibitor p16INK4a also exerts anti-inflammatory effects on rheumatoid synovial fibroblasts (RSF) in CDK activity-dependent and -independent manners. The present study was conducted to discern how p16INK4a modulates macrophages, which are the major source of inflammatory cytokines in inflamed synovial tissues. We found that p16INK4a suppresses LPS-induced production of IL-6 but not of TNF-α from macrophages. This inhibition did not depend on CDK4/6 activity and was not observed in RSF. p16INK4a gene transfer accelerated LPS-triggered IL-1R–associated kinase 1 (IRAK1) degradation in macrophages but not in RSF. The degradation inhibited the AP-1 pathway without affecting the NF-κB pathway. Treatment with a proteosome inhibitor prevented the acceleration of IRAK1 degradation and downregulation of the AP-1 pathway. THP-1 macrophages with forced IRAK1 expression were resistant to the p16INK4a-induced IL-6 suppression. Senescent macrophages with physiological expression of p16INK4a upregulated IL-6 production when p16INK4a was targeted by specific small interfering RNA. These findings indicate that p16INK4a promotes ubiquitin-dependent IRAK1 degradation, impairs AP-1 activation, and suppresses IL-6 production. Thus, p16INK4a senescence gene upregulation inhibits inflammatory cytokine production in macrophages in a different way than in RSF.

Retinoids are known to promote T helper (Th)2 and regulatory T cell (Treg) differentiation, and suppress Th1 and Th17 in vitro. Am80, a synthetic retinoid, is reported to ameliorate collagen-induced arthritis (CIA). The aims of this study are to determine the effects of Am80 on CIA in detail, and on Th development and antibody (Ab) production in vivo. Murine CIA was induced by immunization with bovine type II collagen (CII) at days 1 and 22. Treatment with Am80 from day 1 to 35 significantly lowered clinical arthritis score, suppressed cellular infiltration and bone destruction in the joint, decreased interleukin (IL)-17 and increased interferon (IFN)-gamma production by CII-stimulated splenocytes, and decreased proportion of Foxp3(+) splenic CD4 T cells and serum anti-CII Ab levels. Thus, Am80 inhibited Th17 and Treg and enhanced Th1 differentiation in vivo. In contrast, Am80 applied from day 15 to 35 did not alter arthritis score, IL-17 or IFN-gamma production by CII-stimulated splenocytes, but decreased the proportion of Foxp3(+) splenic CD4 T cells and serum anti-CII Ab levels. Am80 exhibits inhibitory effects on CIA and might regulate both Th development and Ab production in vivo. Decreased Th17 by treatment with Am80 might be responsible for the attenuation of arthritis.

Triggering receptor expressed on myeloid cells (TREM)-1 is inducible on monocyte/macrophages and neutrophils and accelerates tissue destruction by propagating inflammatory responses in diseases related to bacterial infection. Its blockade suppressed fatal immune responses in mice models of sepsis without impairing the host defense. However, the influence of TREM-1 on non-bacterial diseases was not elucidated. We describe here that TREM-1 expression was up-regulated by prostaglandin (PG) E(2) as well as lipopolysaccharide. Activation of TREM-1 expressed on PGE(2)-pretreated peripheral blood mononuclear cells by an agonistic TREM-1 mAb significantly enhanced the production of TNFalpha. Indeed, monosodium urate monohydrate (MSU) crystals induced TREM-1 expression in vitro and in vivo. MSU crystals and an anti-TREM-1 agonistic antibody synergistically increased the production of interleukin-1beta compared with stimulation with the crystals alone. Furthermore, TREM-1 was expressed on CD14+ cells in rheumatoid synovial tissue and synovial macrophages from mice with collagen-induced arthritis (CIA). Blockade of TREM-1 ameliorated CIA without affecting T cell and B cell immune responses to the inducing antigen. These results provide evidence that TREM-1 may contribute the development of non-microbial inflammatory diseases through the enhancement of inflammatory responses.

Purpose of review The aim of this article is to highlight recent advances suggesting essential involvement of the innate immune system in crystal-induced acute inflammation. Recent findings Gout is a disease caused by the deposition of monosodium urate monohydrate crystals. Precise mechanisms underlying the initiation of monosodium urate monohydrate crystal-induced acute inflammation, however, are not known. Recent investigations provided novel evidence in the pathology of acute gout. Immunological study indicated that monosodium urate monohydrate crystals can act as a 'danger signal' that resembles exogenous adjuvants. Two laboratories have documented interesting findings that Toll-like receptor-mediated pathways or MyD88-dependent pathways are involved in monosodium urate monohydrate crystal-induced acute inflammation. Upregulation of the triggering receptor expressed on myeloid cells 1 (TREM-1) in phagocytes by the stimulation with monosodium urate monohydrate crystals has been demonstrated. Furthermore, pathological significance of NALP 3 inflammasome in gout has been shown. These findings provide a new concept that the innate immune system may play a crucial role on the triggering of crystal-induced acute inflammation. Spontaneous resolution is a characteristic feature of acute gout. Involvement of nuclear hormone receptors, peroxisome proliferator-activated receptor gamma and liver X receptor alpha, during the termination of acute gout has been also shown. Summary These studies provided a new insight into the mechanisms underlying the initiation and the termination of monosodium urate monohydrate crystal-induced acute inflammation.

The present study was conducted to investigate whether goat fetal myoblasts with no inherent adipogenic potential can be induced to transdifferentiate into adipocytes. Goat fetal myoblasts were transiently transfected by the adipogenic transcription factors, peroxisome proliferator-activated receptor-gamma (PPARgamma) and CCAAT/enhancer-binding protein-alpha (C/EBPalpha). Both PPARgamma and C/EBPalpha were capable of inducing adipogenic transdifferentiation as indicated by the appearance of mature adipocytes when the transfected cells were cultured in adipogenic differentiation medium (ADM). Ectopic expression of PPARgamma induced endogenous C/EBPalpha expression and vice versa only when the cells were cultured in ADM. Removal of troglitazone, a PPARgamma agonist, from the ADM resulted in a dramatic decline in the number of adipocytes, indicating that PPARgamma stimulation is necessary to induce adipogenic transdifferentiation of goat fetal myoblasts. These results demonstrate for the first time that primary cultured myoblasts can be transdifferentiated into adipocytes.

Lipoxin A 4 (LXA 4 ) is an eicosanoid which is produced via lipoxygenases and characteristic of its anti-inflammatory effect in many metabolites of arachidonic acid, which are mostly pro-inflammatory. Glucocorticoids are well known also for their strong anti-inflammatory action but induce 5-lipoxygenase, essential to synthesize leukotrienes, which are pro-inflammatory. To elucidate the interaction of glucocorticoids and lipoxin A 4 for anti-inflammation, we analyzed in vitro expression of lipoxin A 4 receptor (ALX) on human neutrophils and the in vivo anti-inflammatory effect of glucocorticoids and LXA 4 using a dermal inflammation mouse model. ALX mRNA was up-regulated by dexamethasone (Dex) in human neutrophils. A glucocorticoid receptor antagonist, mifepristone, suppressed up-regulation of ALX induced by Dex. LXA 4 and/or Dex decreased CD11b expression on human neutrophils and suppressed mouse dermatitis induced by LTB 4 . These results suggest that anti-inflammatory effects of glucocorticoids depend at least partly on up-regulation of ALX and that the lipoxin system could be a negative feedback regulator for LTB 4 .

Objective Triggering receptor expressed on myeloid cells 1 (TREM-1) is a cell surface molecule that was recently identified on monocytes and neutrophils. TREM-1 has been implicated in the early inflammatory responses induced by microbes, but its pathophysiologic role in nonmicrobial inflammation remains unknown. In the present study, we investigated the role of TREM-1 in acute inflammation induced by monosodium urate monohydrate (MSU) crystals. Induction of TREM-1 expression by MSU crystal–stimulated murine resident peritoneal macrophages and infiltrating leukocytes in a murine air-pouch model of crystal-induced acute inflammation was determined. The biologic role of TREM-1 in crystal-induced cytokine production by resident peritoneal macrophages was also investigated. Methods TREM-1 expression by resident peritoneal macrophages and infiltrating leukocytes in a murine air-pouch model was determined by quantitative real-time polymerase chain reaction, Western blot analysis, and flow cytometry. Cytokine production by resident peritoneal macrophages after incubation with MSU crystals in the presence or absence of an anti–TREM-1 agonist antibody was determined by enzyme-linked immunosorbent assay. Results TREM-1 expression by resident peritoneal macrophages was significantly induced after stimulation with the crystals. Maximum expression of TREM-1 transcripts and protein occurred at 1 and 4 hours after exposure to the crystals, respectively. Costimulation of resident peritoneal macrophages with MSU crystals and an anti–TREM-1 agonist antibody synergistically increased the production of both interleukin-1β and monocyte chemotactic protein 1 compared with stimulation with the crystals alone. MSU crystals also induced TREM-1 expression in infiltrating leukocytes in a murine air-pouch model of crystal-induced acute inflammation. Conclusion These findings suggest that rapid induction of TREM-1 expression on resident peritoneal macrophages and neutrophils by MSU crystals may contribute to the development of acute gout through enhancement of inflammatory responses.

Interleukin-18 (IL-18) belongs to the interleukin-1 family and was identified as an interferon-gamma inducing factor. We investigated IL-18 mRNA-expressing cells in the mouse uterus. By RNase protection assay, IL-18 mRNA and alpha subunit of IL-18 receptor mRNA were detected in the uterus. In the uterus, IL-18 mRNA levels increased during sexual maturation. In situ hybridization analysis demonstrated IL-18 mRNA-expressing cells in the mouse uterus of different ages. At 21 days of age, IL-18 mRNA-expressing cells were detected in the luminal epithelial cells and stromal cells although the IL-18 mRNA signal was weak. At 42 days of age, IL-18 mRNA signal was mainly detected in the stromal cells located near the myometrium, and in some of the luminal and glandular epithelial cells. In the uterus of 63-day-old adult mice, a strong hybridization signal for IL-18 mRNA was detected at estrus, but was weak at diestrus. IL-18 mRNA was mainly detected in the glandular epithelial cells and stromal cells. The effect of estradiol-17beta (E(2)) on IL-18 mRNA-expressing cells in the uterus was examined in ovariectomized mice. In oil-treated mice IL-18 mRNA signal was localized in luminal epithelial cells and stromal cells, while in E(2)-treated mice IL-18 mRNA signal was localized in stromal cells alone. These results suggest that the mouse uterus has an IL-18 system, and IL-18 exerts a physiological role within the uterus in a paracrine manner, and that IL-18 gene expression is regulated by estrogen.

Interleukin-18 (IL-18) is a proinflammatory cytokine expressed in female reproductive organs in humans, rats and mice. The physiological roles of uterine IL-18 and the regulatory mechanisms of IL-18 gene expression are unclear. The present study aimed to clarify the effects of estradiol-17beta (E2) and progesterone (P4) on IL-18 mRNA expression in the mouse uterus. Distribution and expression levels of IL-18 mRNA were studied using an RNase protection assay. Expression of IL-18 mRNA was observed in all organs studied, including testes, ovaries and uteri. The uterine IL-18 mRNA level of estrous mice was higher than that of diestrous mice. E2 treatment (1, 5, 25 or 250 ng/mouse) decreased uterine IL-18 mRNA levels in ovariectomized mice dose-dependently. E2 treatment acutely decreased IL-18 mRNA levels 3 h after injection, but these levels returned to the initial level after 48 h. P4 treatment (1 mg/mouse) decreased uterine IL-18 mRNA levels after 12 h, but levels returned to the initial level after 48 h. Both uterine IL-18 and IL-18Ralpha mRNAs were detected in cultured endometrial epithelial and stromal cells. These results suggest that uterine IL-18 expression is reduced by sex steroid hormones and that IL-18 acts on endometrial cells in a paracrine or autocrine manner.

Hematopoietic prostaglandin D synthase (PGDS) is a key enzyme to produce prostaglandin (PG) D and J series. These PGs are involved in inflammation and immune system. The PGDS complementary DNA (cDNA)-expressing retrovirally transfected fibroblasts were introduced in vivo, and effect of the expression on lung injury induced by bleomycin was investigated in mice. Intravenous injection of PGDS cDNA-expressing fibroblasts significantly reduced lung edema, leukocyte infiltration in bronchoalveolar lavage (BAL) fluid, and pulmonary collagen content at 4 wk after instillation of bleomycin. Survival rate in mice instilled with the PGDS-expressing fibroblasts was higher than that in mice that received the mock transfection. Administration of 15-deoxy-Delta 12,14-PGJ2, which is a nonenzymatic metabolite of PGD2, also attenuated the lung injury, suggesting mediation of PGs produced by PGDS for the attenuation. Introduction of PGDS cDNA-expressing fibroblasts suppressed expression of basic fibroblast growth factor, connective tissue growth factor, and collagen messenger RNAs in the lungs, as well as the levels of total proteins and hemoglobin in BAL fluid. These data suggest that the suppressive effect of PGDS on the lung injury could be partly mediated by edema formation and inhibition of genes involved in the fibrotic change.

Objective Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a member of the nuclear hormone receptor superfamily and functions as a key regulator of lipid and glucose metabolism, atherosclerosis, and inflammatory responses. This study was undertaken to evaluate the biologic role of PPAR gamma in self-limiting episodes of acute gouty arthritis. To do this, we investigated PPAR gamma expression by monosodium urate monohydrate (MSU) crystal-stimulated monocytes, and we studied the effects of PPAR gamma ligands on crystal-induced acute inflammation. Methods PPAR gamma expression by MSU crystal-stimulated human peripheral blood mononuclear cells was determined by reverse transcription-polymerase chain reaction and immunostaining. Expression of CD36 on monocytes was detected by flow cytometric analysis. The effects of PPAR gamma ligands on in vitro crystal-induced cytokine production and on in vivo cellular infiltration during crystal-induced acute inflammation were also investigated. Results MSU crystals rapidly and selectively induced PPAR gamma expression by monocytes. Gene expression was detected as early as 2 hours, and maximum expression was observed at 4 hours after stimulation. The induced PPAR gamma was functional, since a PPAR gamma ligand was able to up-regulate CD36 expression on monocytes. A natural ligand of PPAR gamma, 15-deoxy-Delta(12,14)-prostaglandin J(2) (15deoxy-PGJ(2)), significantly reduced the crystal-induced production of cytokines by monocytes. Indomethacin inhibited cytokine production only at high concentrations, and an antidiabetic thiazolidinedione (troglitazone) failed to exert significant effects. Administration of troglitazone and 15deoxy-PGJ(2) significantly prevented cellular accumulation in a mouse air-pouch model of MSU crystal-induced acute inflammation. Conclusion Rapid induction of PPAR gamma expression on monocytes by MSU crystals may contribute, at least in part, to the spontaneous resolution of acute attacks of gout.

Objective To investigate the role of interleukin-10 (IL-10) in the inflammatory response, the antiinflammatory effect of retrovirally transfected IL-10 was evaluated both in vitro and in vivo. Methods A recombinant retrovirus containing the murine IL-10 gene was constructed using the pLXSN vector and was designated as LXSN-IL-10. Murine IL-10 was introduced into embryonic C57BL/6J fibroblast cells using LXSN-IL-10 to create C57-IL-10 cells. The effect of IL-10 in the culture supernatant of these cells was then evaluated by determining changes in the production of tumor necrosis factor α (TNFα), macrophage inflammatory protein 1α (MIP-1α), and MIP-1β by macrophages. The antiinflammatory effect of C57-IL-10 cells was also investigated using an in vivo model of monosodium urate monohydrate (MSU) crystal–induced acute inflammation. Results The IL-10 gene transcript and its product were detected by reverse transcriptase–polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The level of IL-10 in the culture supernatant of C57-IL-10 cells was estimated to be 50 ng/ml. The culture supernatant of these cells exerted the biologic activity of IL-10, showing inhibition of TNFα, MIP-1α, and MIP-1β production by macrophages. Injection of C57-IL-10 cells into murine air pouches significantly inhibited MSU crystal–induced cellular infiltration (P < 0.01) and production of the mouse CXC chemokine KC (P < 0.05). These findings were consistent with the results obtained by the injection of recombinant human IL-10 into air pouches. Conclusion In this murine air pouch model of MSU crystal–induced inflammation, IL-10 seemed to inhibit the recruitment of neutrophils at least partly by suppressing KC production. These findings seem to suggest that IL-10 gene therapy may be useful for inflammatory diseases.

Virus-infection-associated (VIA) antigen of foot-and-mouth disease (FMD) virus was prepared from an inactivated FMD vaccine. The VIA antigen coupled with an adjuvant of aluminium hydroxide gel supplemented vaccine was efficiently eluted by suspending and stirring in high concentration of phosphate buffer solution (0.3M, pH 7.6). The final elute purified by DEAE-Sephadex A50 from the vaccine was concentrated in 1/500-1/1,000 of the original volume. VIA antigens prepared from two kinds of vaccine (Type O and Asia-1) were antigenically identical to one prepared from a cell culture infected with live virus. Two cattle were infected with FMD virus (Type O) and sera were obtained from each cattle every week. The VIA antigens from the inactivated vaccine were compared with the ones from the cell culture infected with live virus in agar gel diffusion tests using sera from cattle infected with live virus. The antibodies against the VIA antigen were detected between the second week and the 13th or 14th week after infection. The VIA antigen from an inactivated vaccine would be very useful in FMD free countries like Japan to avoid the risk of using live FMD viruses.

Introduction Increased activity of osteoclasts is responsible for bone loss and joint destruction in rheumatoid arthritis. For osteoclast development and bone resorption activity, cytoskeletal organization must be properly regulated. MicroRNAs (miRNAs) are endogenous small noncoding RNAs that suppress expression of their target genes. This study was conducted to identify crucial miRNAs to control osteoclasts. Methods miRNA expression in the bone marrow-derived macrophages (BMM) with or without receptor activator of nuclear factor κB ligand (RANKL) stimulation was analyzed by miRNA array. To examine the role of specific miRNAs in osteoclast formation, bone resorption activity and actin ring formation, the BMM were retrovirally transduced with miRNA antagomirs. To confirm whether the suppressive effects on osteoclastogenesis by miR-31 inhibition were mediated by targeting RhoA, osteoclast formation was analyzed in the presence of the RhoA inhibitor, exoenzyme C3. Results miR-31 was identified as one of the highly upregulated miRNAs during osteoclast development under RANKL stimulation. Inhibition of miR-31 by specific antagomirs suppressed the RANKL-induced formation of osteoclasts and bone resorption. Phalloidin staining of osteoclasts revealed that actin ring formation at the cell periphery was severely impaired by miR-31 inhibition, and clusters of small ringed podosomes were observed instead. In these osteoclasts, expression of RhoA, one of the miR-31 target genes, was upregulated by miR-31 inhibition in spite of the impaired osteoclastogenesis. Treatment with the RhoA inhibitor, exoenzyme C3, rescued the osteoclastogenesis impaired by miR-31 inhibition. Conclusions miR-31 controls cytoskeleton organization in osteoclasts for optimal bone resorption activity by regulating the expression of RhoA.