Hepatic Pin1 Expression, Particularly in Nuclei, Is Increased in NASH Patients in Accordance with Evidence of the Role of Pin1 in Lipid Accumulation Shown in Hepatoma Cell Lines.

Our previous studies using rodent models have suggested an essential role for Pin1 in the pathogenesis of non-alcoholic steatohepatitis (NASH). In addition, interestingly, serum Pin1 elevation has been reported in NASH patients. However, no studies have as yet examined the Pin1 expression level in human NASH livers. To clarify this issue, we investigated the expression level and subcellular distribution of Pin1 in liver specimens obtained using needle-biopsy samples from patients with NASH and healthy liver donors. Immunostaining using anti-Pin1 antibody revealed the Pin1 expression level to be significantly higher, particularly in nuclei, in the livers of NASH patients than those of healthy donors. In the samples from patients with NASH, the amount of nuclear Pin1 was revealed to be negatively related to serum alanine aminotransferase (ALT), while tendencies to be associated with other serum parameters such as aspartate aminotransferase (AST) and platelet number were noted but did not reach statistical significance. Such unclear results and the lack of a significant relationship might well be attributable to our small number of NASH liver samples (n = 8). Moreover, in vitro, it was shown that addition of free fatty acids to medium induced lipid accumulation in human hepatoma HepG2 and Huh7 cells, accompanied with marked increases in nuclear Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1), in accordance with the aforementioned observations in human NASH livers. In contrast, suppression of Pin1 gene expression using siRNAs attenuated the free fatty acid-induced lipid accumulation in Huh7 cells. Taken together, these observations strongly suggest that increased expression of Pin1, particularly in hepatic nuclei, contributes to the pathogenesis of NASH with lipid accumulation.

Auraptene Enhances AMP-Activated Protein Kinase Phosphorylation and Thereby Inhibits the Proliferation, Migration and Expression of Androgen Receptors and Prostate-Specific Antigens in Prostate Cancer Cells.

Citrus hassaku extract reportedly activates AMPK. Because this extract contains an abundance of auraptene, we investigated whether pure auraptene activates AMPK and inhibits proliferation using prostate cancer cell lines. Indeed, auraptene inhibited the proliferation and migration of LNCaP cells and induced phosphorylation of AMPK or its downstream ACC in LNCaP, PC3, and HEK-293 cells, but not in DU145 cells not expressing LKB1. In addition, the mTOR-S6K pathway, located downstream from activated AMPK, was also markedly suppressed by auraptene treatment. Importantly, it was shown that auraptene reduced androgen receptor (AR) and prostate-specific antigen (PSA) expressions at both the protein and the mRNA level. This auraptene-induced downregulation of PSA was partially but significantly reversed by treatment with AMPK siRNA or the AMPK inhibitor compound C, suggesting AMPK activation to, at least partially, be causative. Finally, in DU145 cells lacking the LKB1 gene, exogenously induced LKB1 expression restored AMPK phosphorylation by auraptene, indicating the essential role of LKB1. In summary, auraptene is a potent AMPK activator that acts by elevating the AMP/ATP ratio, thereby potentially suppressing prostate cancer progression, via at least three molecular mechanisms, including suppression of the mTOR-S6K pathway, reduced lipid synthesis, and AR downregulation caused by AMPK activation.

Clinical Study of Cerebral Ischemia in Moyamoya Disease from the View of Development of the Anterior Choroidal Artery.

OBJECTIVES: The anterior choroidal artery (AchA) is one of the collateral vessels in moyamoya disease (MMD). The incidence of cerebral ischemia in MMD was analyzed through the association between development of the AchA and advancement of MMD stage. MATERIALS AND METHODS: Twelve patients of MMD with cerebral ischemia (infarction; 9 patients, transient ischemic attack; 3 patients) were enrolled. Advancement of MMD was evaluated using Suzuki's stage. The grades in Suzuki's stage were subclassified into a non-progressive stage for grades 1 and 2, and a progressive stage for grades 4 and 5. Dilatation of the AchA was judged as the presence of development of this artery. Development of the AchA was grouped into proximal type and proximal and distal type. RESULTS: Most frequent locations of infarcts were the anterior and parietal lobes in 6 patients each. Development of the AchA was confirmed on the ischemic side in all patients and on the non-ischemic side in 9 patients. Development of the AchA in the progressive stage was limited in the proximal and distal type on both sides. Development of the AchA in the non-progressive stage was the proximal type on the ischemic side. CONCLUSIONS: The cause of cerebral ischemia was possibly associated with inadequate blood supply of the AchA in the non-progressive stage, and the lower blood flow from the internal carotid artery (ICA) in the progressive stage. Disparity between collateral blood flow from the AchA and the blood flow from the ICA was considered to relate to incidence of cerebral ischemia in MMD.

Carnosic Acid and Carnosol Activate AMPK, Suppress Expressions of Gluconeogenic and Lipogenic Genes, and Inhibit Proliferation of HepG2 Cells.

Carnosic acid (CA), carnosol (CL) and rosmarinic acid (RA), components of the herb rosemary, reportedly exert favorable metabolic actions. This study showed that both CA and CL, but not RA, induce significant phosphorylation of AMP-dependent kinase (AMPK) and its downstream acetyl-CoA carboxylase 1 (ACC1) in HepG2 hepatoma cells. Glucose-6-phosphatase (G6PC) and phosphoenolpyruvate carboxykinase 1 (PCK1), rate-limiting enzymes of hepatic gluconeogenesis, are upregulated by forskolin stimulation, and this upregulation was suppressed when incubated with CA or CL. Similarly, a forskolin-induced increase in CRE transcriptional activity involved in G6PC and PCK1 regulations was also stymied when incubated with CA or CL. In addition, mRNA levels of ACC1, fatty acid synthase (FAS) and sterol regulatory element-binding protein 1c (SREBP-1c) were significantly reduced when incubated with CA or CL. Finally, it was shown that CA and CL suppressed cell proliferation and reduced cell viability, possibly as a result of AMPK activation. These findings raise the possibility that CA and CL exert a protective effect against diabetes and fatty liver disease, as well as subsequent cases of hepatoma.

Comparison of tofogliflozin versus glimepiride as the third oral agent added to metformin plus a dipeptidyl peptidase-4 inhibitor in Japanese patients with type 2 diabetes: A randomized, 24-week, open-label, controlled trial (STOP-OB).

Metformin plus a dipeptidyl peptidase-4 inhibitor (DPP-4i) is the most common therapy for Japanese patients with type 2 diabetes. This 24-week, multicentre, open-label, parallel-group trial randomized patients on dual therapy to add-on tofogliflozin (20 mg/day, n = 33) or glimepiride (0.5 mg/day, n = 31). The primary outcome was change in body fat percentage. The secondary outcomes included changes in HbA1c, fat mass, fat-free mass, liver function variables and uric acid. Tofogliflozin and glimepiride reduced HbA1c to a similar extent. Body fat percentage did not change from baseline in either group. Fat mass was reduced by tofogliflozin but was increased by glimepiride (by -2.0 ± 1.7 kg and +1.6 ± 1.6 kg, P = .002). Fat-free mass was also reduced by tofogliflozin and increased by glimepiride (by -1.3 ± 1.3 kg and +0.9 ± 2.0 kg, P < .001). Alanine aminotransferase and uric acid levels were reduced by tofogliflozin (P = .006 and P < .001, respectively). These data provide novel information useful for selecting the third oral agent for patients whose diabetes is inadequately controlled with metformin plus DPP-4i dual therapy.

A case of prosopometamorphopsia caused by infarction of the splenium of the corpus callosum and major forceps.

An adult female complained of enlargement of right eyes in other people. Diffusion-weighted imaging detected an abnormal high-intensity area in the region from the splenium of the corpus callosum to the major forceps on the right side. The patient reported that right eyes appeared larger in size, which suggested prosopometamorphopsia. Adichotic listening test identified left-ear deficit. Acombination of prosopometamorphopsia and left-ear deficit was not identified in the reported patients. Prosopometamorphopsia in most of the reported patients included the eye as did that in our patient. This result suggested the importance of information on the eye in recognizing faces.

Clinical Study of Thirteen Patients with Spinal Cord Infarction.

BACKGROUND: A concept of sensory tracts in the spinal cord has been established in relation to a dorsolateral pathway which is located in the posterior part of the lateral column and conveys the deep sense. METHODS: The clinical status at onset, neurological symptoms, and magnetic resonance imaging (MRI) findings in 13 patients of spinal cord infarction were studied. RESULTS: The clinical status was acute in 11 patients and subacute in 2 patients. Palsy of the extremities was noted in 11 patients. Segmental sensory disturbance was shown in all patients. One patient showed disturbance of all senses and paraplegia, which indicated transverse myelopathy. In the other 12 patients, 11 patients showed impairment of pain sense although joint position sense was preserved, excluding 1 patient whose sensory disturbance showed dysesthesia alone. In these 11 patients, soft touch and vibration senses were impaired in 7 patients. Abnormality of spinal cord MRI was detected 7 patients. The lesions were located in the cervical cord in 3 patients, cervical to thoracic cord in 1 patient, and thoracic cord in 3 patients. CONCLUSIONS: In the 11 patients in whom pain sense was impaired and joint position sense was preserved, involvement of the anterior spinal cord artery (ASCA) was the mainstay. Impairment of vibration sense was accompanied in 7 patients in patients of ASCA infarction. It was speculated that impairment of vibration sense can occur in patients with ASCA infarction whose ischemia spread to the dorsolateral pathway in the posterior part of the lateral column.

Xanthine Oxidase Inhibitor Febuxostat Exerts an Anti-Inflammatory Action and Protects against Diabetic Nephropathy Development in KK-Ay Obese Diabetic Mice.

Hyperuricemia has been recognized as a risk factor for insulin resistance as well as one of the factors leading to diabetic kidney disease (DKD). Since DKD is the most common cause of end-stage renal disease, we investigated whether febuxostat, a xanthine oxidase (XO) inhibitor, exerts a protective effect against the development of DKD. We used KK-Ay mice, an established obese diabetic rodent model. Eight-week-old KK-Ay mice were provided drinking water with or without febuxostat (15 µg/mL) for 12 weeks and then subjected to experimentation. Urine albumin secretion and degrees of glomerular injury judged by microscopic observations were markedly higher in KK-Ay than in control lean mice. These elevations were significantly normalized by febuxostat treatment. On the other hand, body weights and high serum glucose concentrations and glycated albumin levels of KK-Ay mice were not affected by febuxostat treatment, despite glucose tolerance and insulin tolerance tests having revealed febuxostat significantly improved insulin sensitivity and glucose tolerance. Interestingly, the IL-1ß, IL-6, MCP-1, and ICAM-1 mRNA levels, which were increased in KK-Ay mouse kidneys as compared with normal controls, were suppressed by febuxostat administration. These data indicate a protective effect of XO inhibitors against the development of DKD, and the underlying mechanism likely involves inflammation suppression which is independent of hyperglycemia amelioration.

The prolyl isomerase Pin1 increases ß-cell proliferation and enhances insulin secretion.

The prolyl isomerase Pin1 binds to the phosphorylated Ser/Thr-Pro motif of target proteins and enhances their cis-trans conversion. This report is the first to show that Pin1 expression in pancreatic ß cells is markedly elevated by high-fat diet feeding and in ob/ob mice. To elucidate the role of Pin1 in pancreatic ß cells, we generated ß-cell-specific Pin1 KO (ßPin1 KO) mice. These mutant mice showed exacerbation of glucose intolerance but had normal insulin sensitivity. We identified two independent factors underlying impaired insulin secretion in the ßPin1 KO mice. Pin1 enhanced pancreatic ß-cell proliferation, as indicated by a reduced ß-cell mass in ßPin1 KO mice compared with control mice. Moreover, a diet high in fat and sucrose failed to increase pancreatic ß-cell growth in the ßPin1 KO mice, an observation to which up-regulation of the cell cycle protein cyclin D appeared to contribute. The other role of Pin1 was to activate the insulin-secretory step: Pin1 KO ß cells showed impairments in glucose- and KCl-induced elevation of the intracellular Ca2+ concentration and insulin secretion. We also identified salt-inducible kinase 2 (SIK2) as a Pin1-binding protein that affected the regulation of Ca2+ influx and found Pin1 to enhance SIK2 kinase activity, resulting in a decrease in p35 protein, a negative regulator of Ca2+ influx. Taken together, our observations demonstrate critical roles of Pin1 in pancreatic ß cells and that Pin1 both promotes ß-cell proliferation and activates insulin secretion.

Protective Effect of Sex Hormone-Binding Globulin against Metabolic Syndrome: In Vitro Evidence Showing Anti-Inflammatory and Lipolytic Effects on Adipocytes and Macrophages.

Sex hormone-binding globulin (SHBG) is a serum protein released mainly by the liver, and a low serum level correlates with a risk for metabolic syndrome including diabetes, obesity, and cardiovascular events. However, the underlying molecular mechanism(s) linking SHBG and metabolic syndrome remains unknown. In this study, using adipocytes and macrophages, we focused on the in vitro effects of SHBG on inflammation as well as lipid metabolism. Incubation with 20 nM SHBG markedly suppressed lipopolysaccharide- (LPS-) induced inflammatory cytokines, such as MCP-1, TNFα, and IL-6 in adipocytes and macrophages, along with phosphorylations of JNK and ERK. Anti-inflammatory effects were also observed in 3T3-L1 adipocytes cocultured with LPS-stimulated macrophages. In addition, SHBG treatment for 18 hrs or longer significantly induced the lipid degradation of differentiated 3T3-L1 cells, with alterations in its corresponding gene and protein levels. Notably, these effects of SHBG were not altered by coaddition of large amounts of testosterone or estradiol. In conclusion, SHBG suppresses inflammation and lipid accumulation in macrophages and adipocytes, which might be among the mechanisms underlying the protective effect of SHBG, that is, its actions which reduce the incidence of metabolic syndrome.

Roles of Gut-Derived Secretory Factors in the Pathogenesis of Non-Alcoholic Fatty Liver Disease and Their Possible Clinical Applications.

The rising prevalence of non-alcoholic fatty liver disease (NAFLD) parallels the global increase in the number of people diagnosed with obesity and metabolic syndrome. The gut-liver axis (GLA) plays an important role in the pathogenesis of NAFLD/non-alcoholic steatohepatitis (NASH). In this review, we discuss the clinical significance and underlying mechanisms of action of gut-derived secretory factors in NAFLD/NASH, focusing on recent human studies. Several studies have identified potential causal associations between gut-derived secretory factors and NAFLD/NASH, as well as the underlying mechanisms. The effects of gut-derived hormone-associated drugs, such as glucagon-like peptide-1 analog and recombinant variant of fibroblast growth factor 19, and other new treatment strategies for NAFLD/NASH have also been reported. A growing body of evidence highlights the role of GLA in the pathogenesis of NAFLD/NASH. Larger and longitudinal studies as well as translational research are expected to provide additional insights into the role of gut-derived secretory factors in the pathogenesis of NAFLD/NASH, possibly providing novel markers and therapeutic targets in patients with NAFLD/NASH.

The Xanthine Oxidase Inhibitor Febuxostat Suppresses the Progression of IgA Nephropathy, Possibly via Its Anti-Inflammatory and Anti-Fibrotic Effects in the gddY Mouse Model.

Recent clinical studies have demonstrated the protective effect of xanthine oxidase (XO) inhibitors against chronic kidney diseases, although the underlying molecular mechanisms remain unclear. However, to date, neither clinical nor basic research has been carried out to elucidate the efficacy of XO inhibitor administration for IgA nephropathy. We thus investigated whether febuxostat, an XO inhibitor, exerts a protective effect against the development of IgA nephropathy, using gddY mice as an IgA nephropathy rodent model. Eight-week-old gddY mice were provided drinking water with (15 µg/mL) or without febuxostat for nine weeks and then subjected to experimentation. Elevated serum creatinine and degrees of glomerular sclerosis and fibrosis, judged by microscopic observations, were significantly milder in the febuxostat-treated than in the untreated gddY mice, while body weights and serum IgA concentrations did not differ between the two groups. In addition, elevated mRNA levels of inflammatory cytokines such as TNFα, MCP-1, IL-1ß, and IL-6, collagen isoforms and chemokines in the gddY mouse kidneys were clearly normalized by the administration of febuxostat. These data suggest a protective effect of XO inhibitors against the development of IgA nephropathy, possibly via suppression of inflammation and its resultant fibrotic changes, without affecting the serum IgA concentration.

Reduced SHARPIN and LUBAC Formation May Contribute to CCl4- or Acetaminophen-Induced Liver Cirrhosis in Mice.

Linear ubiquitin chain assembly complex (LUBAC), composed of SHARPIN (SHANK-associated RH domain-interacting protein), HOIL-1L (longer isoform of heme-oxidized iron-regulatory protein 2 ubiquitin ligase-1), and HOIP (HOIL-1L interacting protein), forms linear ubiquitin on nuclear factor-κB (NF-κB) essential modulator (NEMO) and induces NF-κB pathway activation. SHARPIN expression and LUBAC formation were significantly reduced in the livers of mice 24 h after the injection of either carbon tetrachloride (CCl4) or acetaminophen (APAP), both of which produced the fulminant hepatitis phenotype. To elucidate its pathological significance, hepatic SHARPIN expression was suppressed in mice by injecting shRNA adenovirus via the tail vein. Seven days after this transduction, without additional inflammatory stimuli, substantial inflammation and fibrosis with enhanced hepatocyte apoptosis occurred in the livers. A similar but more severe phenotype was observed with suppression of HOIP, which is responsible for the E3 ligase activity of LUBAC. Furthermore, in good agreement with these in vivo results, transduction of Hepa1-6 hepatoma cells with SHARPIN, HOIL-1L, or HOIP shRNA adenovirus induced apoptosis of these cells in response to tumor necrosis factor-α (TNFα) stimulation. Thus, LUBAC is essential for the survival of hepatocytes, and it is likely that reduction of LUBAC is a factor promoting hepatocyte death in addition to the direct effect of drug toxicity.

The SGLT2 Inhibitor Luseogliflozin Rapidly Normalizes Aortic mRNA Levels of Inflammation-Related but Not Lipid-Metabolism-Related Genes and Suppresses Atherosclerosis in Diabetic ApoE KO Mice.

Recent clinical studies have revealed the treatment of diabetic patients with sodium glucose co-transporter2 (SGLT2) inhibitors to reduce the incidence of cardiovascular events. Using nicotinamide and streptozotocin (NA/STZ) -treated ApoE KO mice, we investigated the effects of short-term (seven days) treatment with the SGLT2 inhibitor luseogliflozin on mRNA levels related to atherosclerosis in the aorta, as well as examining the long-term (six months) effects on atherosclerosis development. Eight-week-old ApoE KO mice were treated with NA/STZ to induce diabetes mellitus, and then divided into two groups, either untreated, or treated with luseogliflozin. Seven days after the initiation of luseogliflozin administration, atherosclerosis-related mRNA levels in the aorta were compared among four groups; i.e., wild type C57/BL6J, native ApoE KO, and NA/STZ-treated ApoE KO mice, with or without luseogliflozin. Short-term luseogliflozin treatment normalized the expression of inflammation-related genes such as F4/80, TNFα, IL-1ß, IL-6, ICAM-1, PECAM-1, MMP2 and MMP9 in the NA/STZ-treated ApoE KO mice, which showed marked elevations as compared with untreated ApoE KO mice. In contrast, lipid metabolism-related genes were generally unaffected by luseogliflozin treatment. Furthermore, after six-month treatment with luseogliflozin, in contrast to the severe and widely distributed atherosclerotic changes in the aortas of NA/STZ-treated ApoE KO mice, luseogliflozin treatment markedly attenuated the progression of atherosclerosis, without affecting serum lipid parameters such as high density lipoprotein, low density lipoprotein and triglyceride levels. Given that luseogliflozin normalized the aortic mRNA levels of inflammation-related, but not lipid-related, genes soon after the initiation of treatment, it is not unreasonable to speculate that the anti-atherosclerotic effect of this SGLT2 inhibitor emerges rapidly, possibly via the prevention of inflammation rather than of hyperlipidemia.

Prolyl isomerase Pin1 negatively regulates AMP-activated protein kinase (AMPK) by associating with the CBS domain in the γ subunit.

AMP-activated protein kinase (AMPK) plays a critical role in metabolic regulation. In this study, first, it was revealed that Pin1 associates with any isoform of γ, but not with either the α or the ß subunit, of AMPK. The association between Pin1 and the AMPK γ1 subunit is mediated by the WW domain of Pin1 and the Thr(211)-Pro-containing motif located in the CBS domain of the γ1 subunit. Importantly, overexpression of Pin1 suppressed AMPK phosphorylation in response to either 2-deoxyglucose or biguanide stimulation, whereas Pin1 knockdown by siRNAs or treatment with Pin1 inhibitors enhanced it. The experiments using recombinant Pin1, AMPK, LKB1, and PP2C proteins revealed that the protective effect of AMP against PP2C-induced AMPKα subunit dephosphorylation was markedly suppressed by the addition of Pin1. In good agreement with the in vitro data, the level of AMPK phosphorylation as well as the expressions of mitochondria-related genes, such as PGC-1α, which are known to be positively regulated by AMPK, were markedly higher with reduced triglyceride accumulation in the muscles of Pin1 KO mice as compared with controls. These findings suggest that Pin1 plays an important role in the pathogenic mechanisms underlying impaired glucose and lipid metabolism, functioning as a negative regulator of AMPK.

Role of Uric Acid Metabolism-Related Inflammation in the Pathogenesis of Metabolic Syndrome Components Such as Atherosclerosis and Nonalcoholic Steatohepatitis.

Uric acid (UA) is the end product of purine metabolism and can reportedly act as an antioxidant. However, recently, numerous clinical and basic research approaches have revealed close associations of hyperuricemia with several disorders, particularly those comprising the metabolic syndrome. In this review, we first outline the two molecular mechanisms underlying inflammation occurrence in relation to UA metabolism; one is inflammasome activation by UA crystallization and the other involves superoxide free radicals generated by xanthine oxidase (XO). Importantly, recent studies have demonstrated the therapeutic or preventive effects of XO inhibitors against atherosclerosis and nonalcoholic steatohepatitis, which were not previously considered to be related, at least not directly, to hyperuricemia. Such beneficial effects of XO inhibitors have been reported for other organs including the kidneys and the heart. Thus, a major portion of this review focuses on the relationships between UA metabolism and the development of atherosclerosis, nonalcoholic steatohepatitis, and related disorders. Although further studies are necessary, XO inhibitors are a potentially novel strategy for reducing the risk of many forms of organ failure characteristic of the metabolic syndrome.

Physiological and Pathogenic Roles of Prolyl Isomerase Pin1 in Metabolic Regulations via Multiple Signal Transduction Pathway Modulations.

Prolyl isomerases are divided into three groups, the FKBP family, Cyclophilin and the Parvulin family (Pin1 and Par14). Among these isomerases, Pin1 is a unique prolyl isomerase binding to the motif including pSer/pThr-Pro that is phosphorylated by kinases. Once bound, Pin1 modulates the enzymatic activity, protein stability or subcellular localization of target proteins by changing the cis- and trans-formations of proline. Several studies have examined the roles of Pin1 in the pathogenesis of cancers and Alzheimer's disease. On the other hand, recent studies have newly demonstrated Pin1 to be involved in regulating glucose and lipid metabolism. Interestingly, while Pin1 expression is markedly increased by high-fat diet feeding, Pin1 KO mice are resistant to diet-induced obesity, non-alcoholic steatohepatitis and diabetic vascular dysfunction. These phenomena result from the binding of Pin1 to several key factors regulating metabolic functions, which include insulin receptor substrate-1, AMPK, Crtc2 and NF-κB p65. In this review, we focus on recent advances in elucidating the physiological roles of Pin1 as well as the pathogenesis of disorders involving this isomerase, from the viewpoint of the relationships between signal transductions and metabolic functions.

DPP-IV inhibitor anagliptin exerts anti-inflammatory effects on macrophages, adipocytes, and mouse livers by suppressing NF-κB activation.

Dipeptidyl peptidase IV (DPP-IV) expression in visceral adipose tissue is reportedly increased in obese patients, suggesting an association of DPP-IV with inflammation. In this study, first, lipopolysaccharide (LPS)- or palmitate-induced elevations of inflammatory cytokine mRNA expressions in RAW264.7 macrophages were shown to be significantly suppressed by coincubation with a DPP-IV inhibitor, anagliptin (10 µM), despite low DPP-IV expression in the RAW264.7 cells. Regarding the molecular mechanism, LPS-induced degradation of IκBα and phosphorylations of p65, JNK, and p38, as well as NF-κB and AP-1 promoter activities, were revealed to be suppressed by incubation with anagliptin, indicating suppressive effects of anagliptin on both NF-κB and AP-1 signaling pathways. Anagliptin also acted on 3T3-L1 adipocytes, weakly suppressing the inflammatory cytokine expressions induced by LPS and TNFα. When 3T3-L1 and RAW cells were cocultured and stimulated with LPS, the effects of anagliptin on the suppression of cytokine expressions in 3T3-L1 adipocytes were more marked and became evident at the 10 µM concentration. Anti-inflammatory effects of anagliptin were also observed in vivo on the elevated hepatic and adipose expressions and serum concentrations of inflammatory cytokines in association with the suppression of hepatic NF-κB transcriptional activity in LPS-infused mice. Taking these observations together, the anti-inflammatory properties of anagliptin may be beneficial in terms of preventing exacerbation of diabetes and cardiovascular events.

The xanthine oxidase inhibitor febuxostat suppresses development of nonalcoholic steatohepatitis in a rodent model.

Xanthine oxidase (XO) is an enzyme involved in the production of uric acid (UA) from purine nucleotides. Numerous recent studies have revealed the likelihood of metabolic syndrome including nonalcoholic fatty liver disease (NAFLD) or steatohepatitis (NASH) to be related to hyperuricemia. However, it remains unclear whether elevated serum UA during the development of NAFLD or NASH is a cause or a consequence of these diseases. In this study, the XO inhibitor febuxostat was administered to two types of NASH model mice. Febuxostat exerted a strong protective effect against NASH development induced by a high-fat diet containing trans fatty acid (HFDT). In contrast, methionine choline-deficient-diet-induced NASH development not accompanied by hyperuricemia showed no UA normalization, suggesting that the ameliorating effect of febuxostat occurs via the normalization of hyperuricemia itself and/or accompanying molecular mechanism(s) such as oxidative stress. In the HFDT-fed mice, hyperuricemia, elevated alanine aminotransferase, and increased Tunnel-positive cells in the liver were normalized by febuxostat administration. In addition, upregulation of fatty acid oxidation-related genes, fibrotic change, and increases in collagen deposition, inflammatory cytokine expressions, and lipid peroxidation in the HFDT-fed mice were also normalized by febuxostat administration. Taken together, these observations indicate that administration of febuxostat has a protective effect against HFDT-induced NASH development, suggesting the importance of XO in its pathogenesis. Thus XO inhibitors are potentially potent therapies for patients with NASH, particularly that associated with hyperuricemia.

Mosapride citrate improves nonalcoholic steatohepatitis with increased fecal lactic acid bacteria and plasma glucagon-like peptide-1 level in a rodent model.

Several lines of evidence have suggested a role of gut microbiota in the etiology of nonalcoholic steatohepatitis (NASH). NASH subjects reportedly showed a prolonged orocecal transit time coexistent with small intestinal bacterial overgrowth. We considered the possibility that enhanced gastrointestinal motility would influence gut microbiota and thus investigated the effects of the gastroprokinetic agent mosapride citrate (MC) on gut microbiota and the development of NASH using a methionine-choline deficient (MCD) diet-fed rodent model. Mice were divided into three groups, given the normal chow diet (NCD), the MCD diet, or the MCD diet containing 10 mg·kg(-1)·day(-1) of MC (MCD plus MC) for 6 wk. NASH development was evaluated based on hepatic histochemical findings, serum parameters and various mRNA and/or protein expression levels. MC treatment suppressed MCD diet-induced NASH development, with reduced serum lipopolysaccharide and increased plasma glucagon-like peptide-1 (GLP-1) concentrations. Calculation of the relative abundance of each strain based on gut microbiota analyses indicated lactic acid bacteria specifically, such as Bifidobacterium and Lactobacillus, in feces to be decreased in the MCD, compared with the NCD group. Interestingly, the reduction in lactic acid bacteria in the MCD diet group was reversed in the MCD plus MC group. In addition, colon inflammation observed in the MCD diet group was reduced in the MCD plus MC group. Therefore, MC showed a protective effect against MCD diet-induced NASH development in our rodent model, with possible involvements of increased fecal lactic acid bacteria, protection against colon inflammation and elevated plasma GLP-1.