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Diabetic nephropathy (DN) is the result of abnormal systemic and local changes in metabolism and hemodynamics. We have reported that many glycolytic enzymes, such as pyruvate kinase M2 (PKM2), were elevated in the renal glomeruli of type 1 and type 2 diabetic patients who were protected from DN. TEPP46, a small-molecule which activates PKM2 by inducing oligomerization, reversed glomerular pathology in diabetic mice. After 7 months of STZ induced diabetes, mice with PKM2 specific overexpression in podocytes (PPKM2Tg) with podocin promoter, exhibited lower albumin-creatinine ratio (ACR), kidney-body weight ratio, mesangial expansion, basement membrane thickness and podocyte foot process effacement vs. WT diabetic littermates. PPKM2Tg mice exhibited lower expression of fibrotic (FN, TGFβ1 and Col4a) and oxidative stress (p47phox, NOX2 and NOX4) genes and improvement in endothelial function with increased eNOS and VEGF expressions in the glomeruli, compared to diabetic WT mice. Glycolytic and mitochondrial metabolisms as measured by oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) using Seahorse showed striking improvement of impaired mitochondrial maximal respiration capacity and glycolytic rate in isolated glomeruli of diabetic PPKM2Tg mice, in concordance with elevated expressions of mitochondrial related-genes, such as PGC1α. Knocking-down PKM by shRNA in podocyte cell line (pPKMKD) replicated metabolic findings induced by diabetes with dramatic decline of both OCR and glycolytic rate. Re-expressing human PKM1 or PKM2 in pPKMKD cell line reversed impaired mitochondrial function and glycolysis, which were not improved in pPKMKD cells re-expressing with enzymatically inactive human PKM2 gene. These results indicate that PKM2 and its enzymatical function are both necessary in podocytes to improve glomerular mitochondrial abnormalities and delay the progression of DN. Disclosure J. Fu: None. G. L. King: Consultant; Self; Agios, Inc., Medtronic, Other Relationship; Self; Janssen Pharmaceuticals, Inc. T. Shinjo: None. Q. Li: None. R. St-louis: None. K. Park: None. H. Yokomizo: None. M. Yu: None. H. Shah: None. I. Wu: None. Funding Iacocca Family Foundation

SPOCK1 is a calcium-binding matricellular proteoglycan that has been extensively studied in several cancer cells. Previously, we generated a mouse line overexpressing SPOCK1 (Spock1-Tg mouse) and showed that SPOCK1 might play an important role in drug-induced gingival overgrowth, indicating that it possesses physiological functions in non-cancer diseases as well. Although SPOCK1 was reported to be secreted from human adipocytes, its role in adipocyte physiology has not been addressed yet. In this study, SPOCK1 protein expression was confirmed in pancreas, adipose tissues, spleen, and liver of normal diet (ND)-fed mice. Interestingly, SPOCK1 was up-regulated in the pancreas and adipose tissues of the high-fat diet (HFD)-fed mice. Spock1-Tg mice fed with ND showed increased maturation in epididymal and inguinal adipose tissues. In addition, Spock1 overexpression strongly decreased expression of UCP-1 in adipose tissues, suggesting that SPOCK1 might regulate thermogenic function through suppression of UCP-1 expression. Finally, exogenous SPOCK1 treatment directly accelerated the differentiation of 3T3-L1 adipocytes, accompanied by the up-regulation of adipocyte differentiation-related gene expression. In conclusion, we demonstrated for the first time that SPOCK1 induced adipocyte differentiation via the up-regulation of adipogenesis-related genes.

Mesenchymal stem cell (MSC)-derived exosome plays a central role in the cell-free therapeutics involving MSCs and the contents can be customized under disease-associated microenvironments. However, optimal MSC-preconditioning to enhance its therapeutic potential is largely unknown. Here, we show that preconditioning of gingival tissue-derived MSCs (GMSCs) with tumor necrosis factor-alpha (TNF-α) is ideal for the treatment of periodontitis. TNF-α stimulation not only increased the amount of exosome secreted from GMSCs, but also enhanced the exosomal expression of CD73, thereby inducing anti-inflammatory M2 macrophage polarization. The effect of GMSC-derived exosomes on inflammatory bone loss were examined by ligature-induced periodontitis model in mice. Local injection of GMSC-derived exosomes significantly reduced periodontal bone resorption and the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, and these effects were further enhanced by preconditioning of GMSCs with TNF-α. Thus, GMSC-derived exosomes also exhibited anti-osteoclastogenic activity. Receptor activator of NF-κB ligand (RANKL) expression was regulated by Wnt5a in periodontal ligament cells (PDLCs), and exosomal miR-1260b was found to target Wnt5a-mediated RANKL pathway and inhibit its osteoclastogenic activity. These results indicate that significant ability of the TNF-α-preconditioned GMSC-derived exosomes to regulate inflammation and osteoclastogenesis paves the way for establishment of a therapeutic approach for periodontitis.

Clinical studies have suggested that loss of insulin’s action and excessive IGF-1 levels in the glomeruli elevate the risk for diabetic kidney disease (DKD). To define the potential pathogenic role of IGF-1 and insulin signaling in DKD, we generated mice with selective loss of insulin receptor (IR) or IGF-1 receptor (IGF-1R) in the mesangial cells (MCs) by cross breeding IRflox/flox mice with Sm22α-Cre mice (SMIRKO) or IGF-1Rflox/flox mice with Myh11-Cre mice (SMIGF1RKO), and examined urinary albumin excretion (ACR) and mesangial expansion with 6 month duration of streptozotocin (STZ)-induced diabetes. IGF-1 levels were significantly increased by 1.5 fold in the renal cortex, but not in the plasma of all three types of diabetic mice. Diabetes induced elevation of ACR (2.0 fold), glomerular size and mesangial expansion (2.1 fold), in parallel with increased glomerular expressions of fibrosis-related (Tgfβ1, fibronectin and Col3a) and matrix (Has2) genes by 2-3 fold, significantly, in Wt and SMIRKO mice, but were prevented in diabetic SMIGF1RKO mice. In cultured MCs, IGF-1, at physiological levels, and insulin, only at supra-physiological levels, induced the expressions of Has2 (3.8 fold) and Tgfβ1 (1.7 fold). Deletion of IGF-1R, but not IR, in MCs inhibited both IGF-1 and insulin-induced expressions of Has2. Inhibitor of MAP kinase pathway, but not inhibitor of PI3 kinase reduced insulin or IGF-1-induced expressions of Has2 in MCs. IGF-1-induced phosphorylations of IGF-1R (39 fold), Akt (34 fold) and Erk/MAPK (8 fold) were significantly inhibited in both IR or IGF-1R-deleted MCs. Insulin-induced phosphorylations of IR-β (11 fold) and Akt (27 fold) were also decreased in IR-deleted MCs, but surprisingly increased in IGF-1R-deleted MCs. Thus, MAPK activation by elevated glomerular IGF-1 levels via IGF-1R, but not IR, on MCs, may contribute to the pathogenesis of DKD through induction of Has2 and fibrotic genes. Disclosure A. Ishikado: Employee; Self; Sunstar Group. Employee; Spouse/Partner; Sunstar Group. T. Shinjo: None. H. Yokomizo: None. Y. Maeda: None. K. Park: None. W. Qi: None. R. St-Louis: None. Q. Li: None. G.L. King: Research Support; Self; Janssen Pharmaceuticals, Inc.

Increased white rice (WR) with parallel decreased brown rice (BR) consumption has been associated with increased prevalence of type 2 diabetes (T2DM). To test whether WR and BR have differential effects on energy and glucose metabolism, C57BL/6 mice were fed 6 different diets: control diet (CD, 10% Fat), high-fat diet (HFD, 46% Fat) with either no rice, WR or BR. BR and, surprisingly, WR activated PGC1α and UCP-1 expressions in brown adipose tissue (BAT) and increased energy expenditure as measured by oxygen consumption, CO2 release and heat production, resulting in reduced body weight (36%, 23%) and improvements of glucose tolerance and insulin sensitivity while on HFD after 18 weeks. To investigate the underlying mechanism, gut microbial analysis was performed. Gut microbiota composition showed clear differences between HFD vs. CD or vs. the addition of BR or WR. Ratio of Firmicutes to Bacteroidetes was 3.7-fold increased in HFD vs.CD, but decreased by the WR (46%) or BR (59%). Increased alpha diversity was observed by WR and BR on HFD. Heat map binary showed that several genera are different in HFD+BR vs. HFD or HFD+WR vs. HFD. Analysis of family abundance revealed that Lachnospiraceae, Ruminococcaceae and Streptococcaceae are 2.5, 1.2 and 2.6-fold increased in HFD, which were reduced by WR or BR. Analysis of genus abundance showed that Lactococcus, Dorea, Peptococcus, Clostridium XIVb, Johnsonella, Anaerovorax are 2.6, 3.7, 2.9, 2.7, 4.7 and 1.7-fold respectively, increased in HFD, which were reduced by WR or BR on HFD. In addition, mice on BR+HFD showed greater reductions than mice on WR+HFD in family and genus levels. Our results demonstrated that supplementation with BR or WR, to a lesser degree, changed HFD-induced gut microbial composition at family and genus levels, in parallel with improved systemic energy and glucose metabolism via activation of BAT and increased energy expenditure, resulting in reduced body weight and improved insulin sensitivity. Disclosure H. Yokomizo: None. A. Ishikado: Employee; Self; Sunstar Group. Employee; Spouse/Partner; Sunstar Group. T. Shinjo: None. K. Park: None. Y. Maeda: None. Q. Li: None. I. Wu: None. M. Matsumoto: Employee; Self; Sunstar Group. S. Devkota: None. A. Kostic: None. G.L. King: Research Support; Self; Janssen Pharmaceuticals, Inc.

Enamel matrix derivatives (EMDs)-based periodontal tissue regenerative therapy is known to promote healing with minimal inflammatory response after periodontal surgery, i. e., it promotes wound healing with reduced pain and swelling. It has also been reported that macrophages stimulated with amelogenin, a major component of EMD, produce various anti-inflammatory cytokines and growth factors. We previously found that stimulation of monocytes with murine recombinant M180 (rM180) amelogenin suppresses major histocompatibility complex class II (MHC II) gene expression using microarray analysis. However, the detailed molecular mechanisms for this process remain unclear. In the present study, we demonstrated that rM180 amelogenin selectively downmodulates the interferon gamma (IFNγ)-induced cell surface expression of MHC II molecules in macrophages and this mechanism mediated by rM180 appeared to be widely conserved across species. Furthermore, rM180 accumulated in the nucleus of macrophages at 15 min after stimulation and inhibited the protein expression of class II transactivator (CIITA) which controls the transcription of MHC II by IFNγ. In addition, reduced MHC II expression on macrophages pretreated with rM180 impaired the expression of T cell activation markers CD25 and CD69, T cell proliferation ability, and IL-2 production by allogenic CD4+ T lymphocytes in mixed lymphocyte reaction assay. The chromatin immunoprecipitation assay showed that IFNγ stimulation increased the acetylation of histone H3 lysine 27, which is important for conversion to euchromatin, as well as the trimethylation of histone H3 lysine 4 levels in the CIITA promoter IV (p-IV) region, but both were suppressed in the group stimulated with IFNγ after rM180 treatment. In conclusion, the present study shows that amelogenin suppresses MHC II expression by altering chromatin structure and inhibiting CIITA p-IV transcription activity, and attenuates subsequent T cell activation. Clinically observed acceleration of wound healing after periodontal surgery by amelogenin may be partially mediated by the mechanism elucidated in this study. In addition, the use of recombinant amelogenin is safe because it is biologically derived protein. Therefore, amelogenin may also be used in future as an immunosuppressant with minimal side effects for organ transplantation or MHC II-linked autoimmune diseases such as type I diabetes, multiple sclerosis, and rheumatoid arthritis, among others.

Metabolic endotoxemia has been implicated in the pathogenesis of type 2 diabetes. In addition to adipose tissue inflammation, inflammatory cell infiltration is also observed in islets, although its effect on islets is largely unknown. We hypothesized that macrophage infiltration into islets leads to impairment of α or β cell function, which ultimately act to exacerbate the pathophysiology of diabetes. Gene expression in a murine α cell line, αTC1, and β cell line, βTC6, was investigated by DNA microarray after co-culturing the cells with a murine macrophage cell line, RAW 264.7, in the presence or absence of bacterial endotoxin. Among the genes showing highly upregulated expression, genes specifically upregulated only in β cells were evaluated to determine the roles of the gene products on the cellular function of β cells. In both α and β cells, expression of type I interferon-responsive genes was highly upregulated upon endotoxin stimulation. Among these genes, expression of the X-linked inhibitor of apoptosis (Xiap)-associated factor 1 (Xaf1) gene, which is associated with the induction of apoptosis, was specifically enhanced in β cells by endotoxin stimulation. This upregulation appeared to be mediated by macrophage-derived interferon β (IFNβ), as endotoxin-stimulated macrophages produced higher amounts of IFNβ, and exogenous addition of IFNβ into βTC6 cultures resulted in increased Xaf1 protein production and cleaved caspase 3, which accelerated β-cell apoptosis. Macrophages activated by metabolic endotoxemia infiltrated into islets and produced IFNβ, which induced β-cell apoptosis by increasing the expression of Xaf1.

Introduction and Aims Several studies have reported that angiopoietin-like protein 2 (Angptl2) is expressed abundantly in adipocytes and is associated with adipose tissue inflammation. In the present study, we found that osteoblasts and mesenchymal stem cells also expressed Angptl2 at high levels. The aim of this study was to understand the role of Angptl2 in osteoblastic cell differentiation. Methods Angptl2 expression was examined during osteoblast and adipocyte differentiation. The role of Angptl2 on cell differentiation and associated signaling was analyzed by gene knockdown using Angptl2 small interfering ribonucleic acid (siRNA). Results Angptl2 was highly expressed in MC3T3-E1 cells, ST2 cells and primary osteoblasts, but not in RAW264 cells. Inhibition of Angptl2 expression using siRNA markedly inhibited alkaline phosphatase (ALP) expression and osteoblastic differentiation in MC3T3-E1, ST2 cells and primary osteoblasts. Angptl2 siRNA also inhibited adipocyte differentiation in ST2 cells. Treatment of MC3T3-E1 cells with Angptl2 siRNA led to the down-regulation of the activities of several cell signaling pathways, including extracellular signal-regulated kinase (ERK), Jun amino-terminal kinase (JNK), Akt, and nuclear factor kappa B (NF-κB) signals. It also down-regulated the expression of Osterix, but not that of runt-related transcription factor 2 (Runx2), suggesting that Angptl2 is a positive activator of Osterix and its down-stream signals. Treatment of MC3T3-E1 cells with anti-Angptl2 antibodies suppressed ALP gene expression. In addition, treatment of Angptl2 siRNA-treated cells with culture supernatants of normal MC3T3-E1 cells restored ALP gene expression, indicating that Angptl2 acts in an autocrine manner. Conclusions The results suggest that Angptl2 is an autocrine positive regulator of cell differentiation. Thus, it is suggested that Angptl2 regulates not only adipose tissue metabolism but also bone metabolism.

Background and aims Epicatechin (EC) intake has been suggested to be beneficial for the prevention of cardiovascular disorders, and it is well known that adipose tissue inflammation is one of the major risk factors for coronary heart diseases. The purpose of the present study was to determine the in vitro and in vivo effects of EC on adipose tissue inflammation and obesity. Methods and results DNA microarray analysis was performed to evaluate the effects of EC on gene expression in adipocytes co-cultured with bacterial endotoxin-stimulated macrophages. To determine the in vivo effects of the catechin, C57BL/6 mice were fed either a high-fat diet (HFD) or HFD combined with EC, and metabolic changes were observed EC suppressed the expression of many inflammatory genes in the adipocytes co-cultured with endotoxin-stimulated macrophages. Specifically, EC markedly suppressed chemokine (C C motif) ligand 19 (CCL19) expression. The target cell of EC appeared to macrophages. The in vivo study indicated that mice fed the EC-supplemented HFD were protected from diet-induced obesity and insulin resistance. Accordingly, the expression levels of genes associated with inflammation in adipose tissue and in the liver were downregulated in this group of mice. Conclusions EC exerts beneficial effects for the prevention of adipose tissue inflammation and insulin resistance. Since we previously reported that mice deficient in the CCL19 receptor were protected from diet-induced obesity and insulin resistance, it can be concluded that the beneficial effects of EC could be mediated, at least in part, by marked suppression of CCL19 expression.

Few studies have investigated the role of extracellular-matrix proteoglycans in the pathogenesis of drug-induced gingival overgrowth (DIGO). SPOCK1 is an extracellular proteoglycan that induces epithelial to mesenchymal transition (EMT) in several cancer cell lines and exhibits protease-inhibitory activity. However, the role of SPOCK1 in non-cancerous diseases such as DIGO has not been well-addressed. We demonstrated that the expression of SPOCK1, TGF-β1, and MMP-9 in calcium channel blocker-induced gingival overgrowth is higher than that in non-overgrowth tissues. Transgenic mice overexpressing Spock1 developed obvious gingival-overgrowth and fibrosis phenotypes, and positively correlated with EMT-like changes. Furthermore, in vitro data indicated a tri-directional interaction between SPOCK1, TGF-β1, and MMP-9 that led to gingival overgrowth. Our study shows that SPOCK1 up-regulation in a noncancerous disease and SPOCK1-induced EMT in gingival overgrowth occurs via cooperation and crosstalk between several potential signaling pathways. Therefore, SPOCK1 is a novel therapeutic target for gingival overgrowth and its expression is a potential risk of EMT induction in cancerous lesions.

Mesenchymal stem cell (MSC)–derived exosome plays a central role in the cell-free therapeutics involving MSCs and the contents can be customized under disease-associated microenvironments. However, optimal MSC-preconditioning to enhance its therapeutic potential is largely unknown. Here, we show that preconditioning of gingival tissue-derived MSC (GMSC) with tumor necrosis factor-alpha (TNF-α) is ideal for the treatment of periodontitis. TNF-α stimulation not only increased the amount of exosome secreted from GMSC, but also enhanced the exosomal expression of CD73, thereby inducing anti-inflammatory M2 macrophage polarization. The effect of GMSC-derived exosomes on inflammatory bone loss were examined by ligature-induced periodontitis model in mice. Local injection of GMSCs-derived exosomes significantly reduced periodontal bone resorption and the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, and these effects were further enhanced by preconditioning of GMSCs with TNF-α. Thus, GMSCs-derived exosomes also exhibited anti-osteoclastogenic activity. Receptor activator of NF-κB ligand (RANKL) expression was regulated by Wnt5a in periodontal ligament cells (PDLCs), and exosomal miR-1260b was found to target Wnt5a-mediated RANKL pathway and inhibit its osteoclastogenic activity. These results indicate that significant ability of the TNF-α-preconditioned GMSC-derived exosomes to regulate inflammation and osteoclastogenesis paves the way for establishment of a new therapeutic approach for periodontitis.

Background The chemokine receptor CCR7, expressed on various immune cells, is associated with cell migration and lympho-node homing. Mice lacking Ccr7 are protected from diet-induced obesity and subsequent insulin resistance. We evaluated the mechanism underlying these protective effects from the standpoint of energy expenditure. Methods Wild-type and Ccr7 null mice were fed a high-fat diet, and the regulation of energy metabolism and energy metabolism-related molecules, e.g., Ucp1, Cidea, and Pgc1α, were evaluated. Results Food intake did not differ between groups. O2 consumption and CO2 production were higher in Ccr7 null mice than in wild-type mice, despite a similar respiratory quotient and glucose and lipid utilization, suggesting that energy expenditure increased in Ccr7 null mice via enhanced metabolism. In white adipose tissues of Ccr7 null mice, Prdm16, Cd137, Tmem26, Th, and Tbx1 expression increased. Similarly, in brown adipose tissues of Ccr7 null mice, Dio2, Pgc1α, Cidea, Sirt1, and Adiponectin expression increased. In both white and brown adipose tissues, Ucp1 gene and protein expression levels were higher in null mice than in wild-type mice. Conclusions In Ccr7 null mice, browning of white adipocytes as well as the activation of brown adipocytes cause enhanced energy metabolism, resulting in protection against diet-induced obesity. Electronic supplementary material The online version of this article (10.1186/s12986-019-0372-5) contains supplementary material, which is available to authorized users.

Elevated expression of pyruvate kinase isoform M2 (PKM2) in the renal glomeruli of people with diabetes is associated with protection from nephropathy even with hyperglycemia. Furthermore, systemic use of PKM2 activators (TEPP46) can prevent or reverse glomerular pathology in diabetic mice. To determine specifically the role of PKM2 in the development or progression of diabetic glomerulopathy, we generated transgenic mice overexpressing PKM2 specific targeted to the podocytes (PPKM2Tg mice) driven by the podocin promoter. Analysis of the glomeruli from these mice showed 1.5-fold increases in mRNA and protein levels without changes in PKM1, compared to wild type (WT) littermates (p400mg/dL for 7 months. Diabetic PPKM2Tg mice showed significantly lower urinary albumin-creatinine ratio (ACR) and kidney weight-body weight ratios (p Disclosure T. Shinjo: None. R. St-Louis: None. J. Fu: None. K. Park: None. Q. Li: None. H. Yokomizo: None. M. Yu: None. H. Wang: None. A. Kannt: Employee; Self; Sanofi. T. Sadowski: Employee; Self; Sanofi-Aventis Deutschland GmbH. G.L. King: Research Support; Self; Sanofi. Funding National Institutes of Health; Sanofi

Increased consumption of white rice (WR) with parallel decreased use of brown rice (BR) have been associated with increased prevalence of type 2 diabetes (T2DM), suggesting WR may elevate the risk of T2DM. To test whether WR or BR have differential effects on glucose metabolism in diet-induced obesity, C57BL/6 mice were fed 6 different diets: control diet (CD, 10%), high fat diet (HFD, 46%) and CD and HFD with either WR or BR. Diets with WR or BR were controlled with comparable carbohydrate and protein contents. After 18 weeks, the median weights of HFD mice were greater (36%) than those on CD. Surprisingly, adding WR or BR to HFD decreased weight gains equally by 53% with parallel reduction of abdominal, visceral, subcutaneous, and total fat vs. HFD. Activity and food intake did not change among mice on HFD. However, HFD decreased heat, VO2, and VCO2 production vs. CD which were normalized by adding WR or BR, per indirect calorimetry with metabolic cages. Intraperitoneal glucose tolerance test on HFD were improved by either WR or BR, although mice on BR+HFD exhibited greater improvements than mice on WR+HFD (P Disclosure H. Yokomizo: None. A. Ishikado: Employee; Self; Sunstar Inc.. Employee; Spouse/Partner; Sunstar Inc.. T. Shinjo: None. K. Park: None. Y. Maeda: None. I. Wu: None. D.M. Pober: None. S. Devkota: None. M. Matsumoto: Employee; Self; Sunstar Inc.. A. Kostic: None. G.L. King: Research Support; Self; Sanofi-Aventis.

Objectives It is well-known that the complement system plays an essential role in host immunity. Observational studies have indicated that complement system-related molecules such as complement factor B (CfB) and other components are correlated with obesity and/or insulin resistance parameters. In this study, we investigated the role of adipocyte-derived CfB in adipose tissue metabolism. Methods We investigated the expression level of complement system-related genes in adipocytes. To understand the role of CfB in adipocyte, we performed Cfb overexpression in 3T3-L1 preadipocytes and generated adipocyte-specific Cfb transgenic mice. Results Cfb expression was markedly enhanced in 3T3-L1 adipocytes co-cultured with macrophages following endotoxin stimulation. In Cfb-overexpressing cells, the expression of adipocyte differentiation/maturation-related genes encoding peroxisome proliferator-activated receptor γ (Pparγ), adipocyte Protein 2 and perilipin was significantly enhanced. Cfb transgenic mice showed a marked increase in the expression of genes encoding Pparγ, perilipin, sterol regulatory element-binding protein 1 c, and Cd36 in the subcutaneous adipose tissue. Conclusions CfB plays a crucial role in late-phase of adipocyte differentiation and subsequent lipid droplet formation.

Periodontal disease is known as the sixth complication of diabetes. Recently, many clinical and epidemiologic reports have shown that local periodontal inflammation induces systemic micro-inflammation, contributing to insulin resistance and increasing the risk of cardiovascular diseases. We have used in vitro and in vivo studies to address the amplification mechanism of periodontal inflammation from the viewpoint of adipocyte–macrophage interaction. Our studies suggest that inflammatory cytokines, such as tumor necrosis factor-alpha (TNFα), are secreted from monocytes and macrophages that are stimulated by periodontal pathogen-derived Toll-like receptor ligands, such as lipopolysaccharides (LPS). TNFα then activates both adipocytes and infiltrated macrophages, thereby amplifying micro-inflammation through the synergistic production of inflammatory cytokines, including interleukin-6 and monocyte chemoattractant protein-1. Additionally, the expression of chemokine (C-C motif) ligand 19 (CCL19), involved in homing of dendritic cells, was found to be markedly upregulated in adipocytes co-cultured with LPS-stimulated macrophages. In vivo studies suggest that CCR7-CCL19 signaling possibly plays a critical role in adipose tissue metabolism through infiltration of immune cells, such as dendritic cells. Furthermore, the Hiroshima study, a clinical intervention study on diabetic patients receiving periodontal treatment, clearly showed that periodontal treatment combined with local oral antibiotic administration could improve glycated hemoglobin levels in subjects with a high-sensitivity C-reactive protein level > 500 ng/ml and a body mass index of approximately 25 kg/m2. A series of our studies suggests that periodontal treatment could improve glycemic control in diabetic patients with mild obesity.

Interleukin-17A (IL-17A) is known to induce inflammatory responses and to be involved in the pathogenesis of not only autoimmune diseases, but also several metabolic and infectious diseases. In this study, IL-17A is shown to induce IL-6 expression in 3T3-L1 mature adipocytes. Interestingly, we found that IL-17A synergistically amplified TNFα-induced secretion of IL-6 and upregulation of IL-17RA expression in 3T3-L1 adipocytes. Its synergistic effects on IL-6 production were inhibited by pre-treatment with inhibitors of IκBα and JNK. Furthermore, IL-17A cooperatively enhanced LPS-mediated IL-6 production in 3T3-L1 adipocytes co-cultured with RAW264.7 macrophages. In addition, IL-17A also enhanced CCL20 production in 3T3-L1 adipocytes stimulated with TNFα or co-cultured with LPS-stimulated RAW macrophages. In high-fat diet-fed mouse epididymal adipose tissues, IL-17RA and RORγt mRNA levels were significantly increased and the serum level of CCL20 was also upregulated. Taken together, these data show that, in adipose tissues, IL-17A contributes to exacerbating insulin resistance-enhancing IL-6 production and promotes the infiltration of Th17 cells in cooperation with TNFα; these findings represent a novel hypothesis for the association between IL-17A-producing cells and type 2 diabetes.

Gut microbiota play essential roles in host physiology. The gut microbiota both influence and are influenced by gastrointestinal (GI) motility. Disruption of intestinal homeostasis and alterations of the gut microbiota are considered to contribute to the pathogenesis of several disorders. Patients suffering from inflammatory disorders, such as inflammatory bowel disease (IBD) and non-alcoholic steatohepatitis (NASH), reportedly have prolonged orocecal transit times with small intestinal bacterial overgrowth and alterations of gut microbiota. These forms of dysbiosis have been suggested to elicit distinct intestinal immune responses, increased intestinal permeability and bacterial translocation, thereby contributing to the pathogenesis of IBD and/or NASH. In a recent report, we raised the possibility that a drug affecting GI motility might influence gut microbiota and the development of NASH. Thus, we investigated the effects of the gastroprokinetic agent mosapride citrate (MC) using a methionine-choline deficient (MCD) diet-induced NASH rodent model. MC treatment exerted a protective effect against MCD diet-induced GI transit time delay, diminished lactic acid bacteria and colonic inflammation, thereby ameliorating NASH with reduced serum endotoxin and increased glucagon-like peptiede-1. Recently, the correction of dysbiosis employing probiotics or fecal transplantation has been investigated as a therapeutic strategy for IBD and NASH. Given the interactive functions of gut microbiota and mediators of GI motility, there is possibility that altering GI motility also has potential as a therapeutic strategy.