Iron Homeostasis and Energy Metabolism in Obesity.

Iron plays a role in energy metabolism as a component of vital enzymes and electron transport chains (ETCs) for adenosine triphosphate (ATP) synthesis. The tricarboxylic acid (TCA) cycle and oxidative phosphorylation are crucial in generating ATP in mitochondria. At the mitochondria matrix, heme and iron-sulfur clusters are synthesized. Iron-sulfur cluster is a part of the aconitase in the TCA cycle and a functional or structural component of electron transfer proteins. Heme is the prosthetic group for cytochrome c, a principal component of the respiratory ETC. Regarding fat metabolism, iron regulates mitochondrial fat oxidation and affects the thermogenesis of brown adipose tissue (BAT). Thermogenesis is a process that increases energy expenditure, and BAT is a tissue that generates heat via mitochondrial fuel oxidation. Iron deficiency may impair mitochondrial fuel oxidation by inhibiting iron-containing molecules, leading to decreased energy expenditure. Although it is expected that impaired mitochondrial fuel oxidation may be restored by iron supplementation, its underlying mechanisms have not been clearly identified. Therefore, this review summarizes the current evidence on how iron regulates energy metabolism considering the TCA cycle, oxidative phosphorylation, and thermogenesis. Additionally, we relate iron-mediated metabolic regulation to obesity and obesity-related complications.

Co-occurrence of cfr-mediated linezolid-resistance in ST398 LA-MRSA and non-aureus staphylococci isolated from a pig farm.

Linezolid resistance, mediated by the cfr gene, which confers resistant phenotypes to phenicols, lincosamides, oxazolidinones, pleuromutilins, and streptogramin A antimicrobials, has emerged in S. aureus and non-aureus staphylococci (NAS). Moreover, due to the transferable potential via plasmids, the spread of cfr among staphylococci is of great concern. In the present study, we investigated the prevalence of cfr-mediated linezolid resistance in ST398 methicillin-resistant S. aureus (MRSA) and NAS strains isolated from a pig farm. Among the 26 staphylococci isolates collected from a pig farm, 14 cfr-harboring ST398 MRSA and NAS (S. epidermidis, S. pasteuri, S. cohnii, and S. rostri) strains were resistant to linezolid and also carried the fexA gene. Comparative genome analysis of cfr-carrying linezolid-resistant ST398 MRSA and NAS (S. pasteuri, S. cohnii, and S. epidermidis) strains revealed that the segments harboring cfr in different staphylococcal strains showed ≥ 99 % sequence identity and the corresponding region containing the cfr, fexA, and Tn558 elements were located in a 38-kb plasmid, designated pSA12 of ST398 MRSA. These observations indicate that the cfr-carrying plasmids and/or fragments may be disseminated among staphylococci in a pig farm and possibly transmitted to staphylococci of human origin, subsequently posing a threat to public health. This is the first report of the co-existence of cfr in linezolid-resistant ST398 MRSA and NAS isolated from a pig farm in South Korea.

Greater adherence to the dietary approaches to stop hypertension dietary pattern is associated with preserved muscle strength in patients with autosomal dominant polycystic kidney disease: a single-center cross-sectional study.

The present study aimed to determine whether certain diets lower the risk of low muscle strength in patients with autosomal dominant polycystic kidney disease (ADPKD). In this cross-sectional study, outpatient ADPKD patients were enrolled from a tertiary care hospital. Muscle strength was assessed on the basis of handgrip strength (HGS), and dietary pattern indices were calculated using dietary intake data. Among the 68 participants included in this study, 19 (27.9%) had low HGS. Cystatin C concentrations were significantly higher in all participants, and in women in the low compared to the normal HGS group in the unadjusted analyses (P = 0.004). Among analyzed dietary pattern indices, the Dietary Approaches to Stop Hypertension (DASH) score was lower, for all participants and men, in the low compared to the normal HGS group (P < 0.05). Especially, the component score for whole grains of the DASH score was significantly lower in men in the low compared to the normal HGS group in unadjusted analyses. The DASH score was positively correlated with HGS in men (r = 0.387, P = 0.046). In addition, logistic regression analysis showed that the DASH score was negatively associated with low HGS, for all participants (odds ratio = 0.851, P = 0.049) and men (odds ratio = 0.716, P = 0.043), after adjusting for age, sex, and body weight. These findings suggest that the DASH dietary pattern may promote the preservation of muscle strength in ADPKD patients. The DASH diet can be considered as a nutritional strategy to maintain muscle strength and prevent sarcopenia in ADPKD patients.

Rapid Weight Change Over Time Is a Risk Factor for Adverse Outcomes in Patients With Predialysis Chronic Kidney Disease: A Prospective Cohort Study.

OBJECTIVE: Both obesity and being underweight are risk factors for adverse outcomes in chronic kidney disease (CKD) patients. However, the effects of longitudinal weight changes on patients with predialysis CKD have not yet been studied. In this study, we analyzed the effects of weight change over time on the adverse outcomes in predialysis CKD population. METHODS: Longitudinal data from a multicenter prospective cohort study (KNOW-CKD) were analyzed. In a total of 2,022 patients, the percent weight change per year were calculated using regression analysis and the study subjects were classified into five categories: group 1, ≤ -5%/year; group 2, -5< to ≤ -2.5%/year; group 3, -2.5< to <2.5%/year; group 4, 2.5≤ < 5%/year; and group 5, ≥5%/year. The incidences of end-stage renal disease (ESRD) and the composite outcome of cardiovascular disease (CVD) and death were calculated in each group and compared to group 3 as reference. RESULTS: During a median 4.4 years of follow-up, 414 ESRD, and 188 composite of CVD and mortality events occurred. Both weight gain and loss were independent risk factors for adverse outcomes. There was a U-shaped correlation between the degree of longitudinal weight change and ESRD (hazard ratio 3.61, 2.15, 1.86 and 3.66, for group 1, 2, 4 and 5, respectively) and composite of CVD and death (hazard ratio 2.92, 2.15, 1.73 and 2.54, respectively), when compared to the reference group 3. The U-shape correlation was most prominent in the subgroup of estimated glomerular filtration rate <45 mL/min/1.73 m2. CONCLUSION: Both rapid weight gain and weight loss are associated with high risk of adverse outcomes, particularly in the advanced CKD.

Unveiling the Crucial Role of Type IV Secretion System and Motility of Helicobacter pylori in IL-1ß Production via NLRP3 Inflammasome Activation in Neutrophils.

Helicobacter pylori is a gram-negative, microaerophilic, and spiral-shaped bacterium and causes gastrointestinal diseases in human. IL-1ß is a representative cytokine produced in innate immune cells and is considered to be a key factor in the development of gastrointestinal malignancies. However, the mechanism of IL-1ß production by neutrophils during H. pylori infection is still unknown. We designed this study to identify host and bacterial factors involved in regulation of H. pylori-induced IL-1ß production in neutrophils. We found that H. pylori-induced IL-1ß production is abolished in NLRP3-, ASC-, and caspase-1/11-deficient neutrophils, suggesting essential role for NLRP3 inflammasome in IL-1ß response against H. pylori. Host TLR2, but not TLR4 and Nod2, was also required for transcription of NLRP3 and IL-1ß as well as secretion of IL-1ß. H. pylori lacking cagL, a key component of the type IV secretion system (T4SS), induced less IL-1ß production in neutrophils than did its isogenic WT strain, whereas vacA and ureA were dispensable. Moreover, T4SS was involved in caspase-1 activation and IL-1ß maturation in H. pylori-infected neutrophils. We also found that FlaA is essential for H. pylori-mediated IL-1ß production in neutrophils, but not dendritic cells. TLR5 and NLRC4 were not required for H. pylori-induced IL-1ß production in neutrophils. Instead, bacterial motility is essential for the production of IL-1ß in response to H. pylori. In conclusion, our study shows that host TLR2 and NLRP3 inflammasome and bacterial T4SS and motility are essential factors for IL-1ß production by neutrophils in response to H. pylori.

Acinetobacter pullorum sp. nov., Isolated from Chicken Meat.

A bacterial strain, designated B301T and isolated from raw chicken meat obtained from a local market in Korea, was characterized and identified using a polyphasic taxonomic approach. Cells were gram-negative, non-motile, obligate-aerobic coccobacilli that were catalase-positive and oxidase-negative. The optimum growth conditions were 30°C, pH 7.0, and 0% NaCl in tryptic soy broth. Colonies were round, convex, smooth, and cream-colored on tryptic soy agar. Strain B301T has a genome size of 3,102,684 bp, with 2,840 protein-coding genes and 102 RNA genes. The 16S rRNA gene analysis revealed that strain B301T belongs to the genus Acinetobacter and shares highest sequence similarity (97.12%) with A. celticus ANC 4603T and A. sichuanensis WCHAc060041T. The average nucleotide identity and digital DNA-DNA hybridization values for closely related species were below the cutoff values for species delineation (95-96% and 70%, respectively). The DNA G+C content of strain B301T was 37.0%. The major respiratory quinone was Q-9, and the cellular fatty acids were primarily summed feature 3 (C16:1 ω6c/C16:1 ω7c), C16:0, and C18:1 ω9c. The major polar lipids were phosphatidylethanolamine, diphosphatidyl-glycerol, phosphatidylglycerol, and phosphatidyl-serine. The antimicrobial resistance profile of strain B301T revealed the absence of antibiotic-resistance genes. Susceptibility to a wide range of antimicrobials, including imipenem, minocycline, ampicillin, and tetracycline, was also observed. The results of the phenotypic, chemotaxonomic, and phylogenetic analyses indicate that strain B301T represents a novel species of the genus Acinetobacter, for which the name Acinetobacter pullorum sp. nov. is proposed. The type strain is B301T (=KACC 21653T = JCM 33942T).

Supplementation with Nicotinamide Riboside Reduces Brain Inflammation and Improves Cognitive Function in Diabetic Mice.

The purpose of this study is to investigate whether nicotinamide riboside (NR) can improve inflammation and cognitive function in diabetic mice. ICR male mice were fed for 14 weeks with either high-fat chow diet (HF, 60% kcal fat) or standard chow diet (CON, 10% kcal fat). HF, streptozotocin, and nicotinamide were used to induce hyperglycemia. NR or vehicle was delivered via stomach gavage for six weeks. Oral glucose tolerance test, Y-maze test, and nest construction test were conducted before and after the NR treatment period. NR treatment induced down-regulation of NLRP3, ASC, and caspase-1. NR reduced IL-1 expression significantly by 50% in whole brains of hyperglycemic mice. Other inflammatory markers including TNF-α and IL-6 were also attenuated by NR. Brain expression of amyloid-ß precursor protein and presenilin 1 were reduced by NR. In addition, NR induced significant reduction of amyloid-ß in whole brains of diabetic mice. NR treatment restored hyperglycemia-induced increases in brain karyopyknosis to the levels of controls. Nest construction test showed that NR improved hippocampus functions. Spatial recognition memory and locomotor activity were also improved by NR supplementation. These findings suggest that NR may be useful for treating cognitive impairment by inhibiting amyloidogenesis and neuroinflammation.

Effects of Piceatannol and Resveratrol on Sirtuins and Hepatic Inflammation in High-Fat Diet-Fed Mice.

Piceatannol (PIC) is a natural hydroxylated analog of resveratrol (RSV) and considered as a potential metabolic regulator. The purpose of this study was to compare the effects of PIC and RSV on parameters affecting inflammation, oxidative stress, and sirtuins (Sirt). Male C57BL/6J mice, 20 weeks old, were assigned to the following groups; (1) lean control, (2) high-fat diet control (HF), (3) HF_PIC, and (4) HF_RSV. Oral administration of PIC and RSV (10 mg/kg/day) for 4 weeks improved glucose control as shown by decreasing levels of area under the curve (AUC) during the oral glucose tolerance test compared with HF group. PIC improved glycemic control by increasing hepatic levels of insulin receptor and AMP-activated protein kinase. PIC increased the levels of Sirt1, Sirt3, and Sirt6 and also increased two downstream targets of Sirt, peroxisome proliferator-activated receptor gamma coactivator 1-alpha and forkhead box O1, in the liver. The inflammatory markers, interleukin (IL)-1 and IL-6, in the liver were downregulated by RSV treatment. Exposure to PIC and RSV significantly lowered hepatic levels of tumor necrosis factor-alpha. However, PIC and RSV treatments showed minimal effects on hepatic markers of oxidative stress. The levels of antioxidant enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO1), were only increased in livers of RSV-treated mice compared with HF control mice. In conclusion, PIC was superior to an equal concentration of RSV in the regulation of Sirt and its downstream targets as well as insulin signaling-related parameters, while RSV potentially suppressed levels of proinflammatory markers and increased NQO1 protein levels.

Nicotinamide riboside regulates inflammation and mitochondrial markers in AML12 hepatocytes.

BACKGROUND/OBJECTIVES: The NAD+ precursor nicotinamide riboside (NR) is a type of vitamin B3 found in cow's milk and yeast-containing food products such as beer. Recent studies suggested that NR prevents hearing loss, high-fat diet-induced obesity, Alzheimer's disease, and mitochondrial myopathy. The objective of this study was to investigate the effects of NR on inflammation and mitochondrial biogenesis in AML12 mouse hepatocytes. MATERIALS/METHODS: A subset of hepatocytes was treated with palmitic acid (PA; 250 µM) for 48 h to induce hepatocyte steatosis. The hepatocytes were treated with NR (10 µM and 10 mM) for 24 h with and without PA. The cell viability and the levels of sirtuins, inflammatory markers, and mitochondrial markers were analyzed. RESULTS: Cytotoxicity of NR was examined by PrestoBlue assay. Exposure to NR had no effect on cell viability or morphology. Gene expression of sirtuin 1 (Sirt1) and Sirt3 was significantly upregulated by NR in PA-treated hepatocytes. However, Sirt1 activities were increased in hepatocytes treated with low-dose NR. Hepatic pro-inflammatory markers including tumor necrosis factor-alpha and interleukin-6 were decreased in NR-treated cells. NR upregulated anti-inflammatory molecule adiponectin, and, tended to down-regulate hepatokine fetuin-A in PA-treated hepatocytes, suggesting its inverse regulation on these cytokines. NR increased levels of mitochondrial markers including peroxisome proliferator-activated receptor γ coactivator-1α, carnitine palmitoyltransferase 1, uncoupling protein 2, transcription factor A, mitochondrial and mitochondrial DNA in PA-treated hepatocytes. CONCLUSIONS: These data demonstrated that NR attenuated hepatic inflammation and increased levels of mitochondrial markers in hepatocytes.

Potential role of host defense antimicrobial peptide resistance in increased virulence of health care-associated MRSA strains of sequence type (ST) 5 versus livestock-associated and community-associated MRSA strains of ST72.

The most significant community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in Korea is sequence type (ST) 72 with staphylococcal cassette chromosome mec (SCCmec) type IV (ST72-MRSA-IV). Although the impact of CA-MRSA on the clinical outcomes versus healthcare-associated (HA)-MRSA remains unclear, it has recently been revealed that ST5 HA-MRSA-II is associated with higher mortality compared with ST72 CA-MRSA-IV, suggesting higher virulence in ST5 HA-MRSA-II strains. In this investigation, human-/animal-originated ST72-MRSA-IV strains were examined for virulence phenotypes and compared with those of ST5-MRSA-II strains, the established HA-MRSA in Korea. Overall, ST5 HA-MRSA-II strains demonstrated higher levels of resistance to host defense-cationic antimicrobial peptides of human (LL-37), bovine (BMAP-28), and bacterial (polymyxin B) origins versus ST72-MRSA-IV strains via enhanced surface positive charge. Hemolysis profiles, gelatinase activity, and staphylococcal superantigen gene profiles were not different between ST72 CA-MRSA and ST5 HA-MRSA strains. However, ST5 HA-MRSA strains were able to downregulate initial cytokine response in murine macrophages.

Serum metabolite profile associated with incident type 2 diabetes in Koreans: findings from the Korean Genome and Epidemiology Study.

The identification of metabolic alterations in type 2 diabetes (T2D) is useful for elucidating the pathophysiology of the disease and in classifying high-risk individuals. In this study, we prospectively examined the associations between serum metabolites and T2D risk in a Korean community-based cohort (the Ansan-Ansung cohort). Data were obtained from 1,939 participants with available metabolic profiles and without diabetes, cardiovascular disease, or cancer at baseline. The acylcarnitine, amino acid, amine, and phospholipid levels in fasting serum samples were analyzed by targeted metabolomics. During the 8-year follow-up period, we identified 282 cases of incident T2D. Of all metabolites measured, 22 were significantly associated with T2D risk. Specifically, serum levels of alanine, arginine, isoleucine, proline, tyrosine, valine, hexose and five phosphatidylcholine diacyls were positively associated with T2D risk, whereas lyso-phosphatidylcholine acyl C17:0 and C18:2 and other glycerophospholipids were negatively associated with T2D risk. The associated metabolites were further correlated with T2D-relevant risk factors such as insulin resistance and triglyceride indices. In addition, a healthier diet (as measured by the modified recommended food score) was independently associated with T2D risk. Alterations of metabolites such as amino acids and choline-containing phospholipids appear to be associated with T2D risk in Korean adults.

Nucleotide-Binding Oligomerization Domain 2 Contributes to Limiting Growth of Mycobacterium abscessus in the Lung of Mice by Regulating Cytokines and Nitric Oxide Production.

Mycobacterium abscessus is a prominent cause of pulmonary infection in immunosuppressed patients and those with cystic fibrosis. Nucleotide-binding oligomerization domain (NOD) 2 is a cytosolic receptor which senses a bacterial peptidoglycan component, muramyl dipeptide (MDP). Although nucleotide-binding oligomerization domain 2 (NOD2) contributes to protect host against various microbial infections, it is still unclear whether NOD2 is essential to regulate host immune responses against M. abscessus infection. In this study, we sought to clarify the role of NOD2 and the underlying mechanism in host defense against M. abscessus infection. Mice were infected intranasally with M. abscessus and sacrificed at indicated time points. Bacterial survival, cytokines production, and pathology in the lungs were determined. Bone marrow-derived macrophages were used to clarify cellular mechanism of NOD2-mediated immune response. Bacterial clearance was impaired, and pathology was more severe in the lungs of NOD2-deficient mice compared with the wild-type mice. In macrophages, NOD2-mediated activation of p38 and JNK were required for production of proinflammatory cytokines and nitric oxide (NO) and expression of iNOS in response to M. abscessus. NO was critical for limiting intracellular growth of the pathogen. Intranasal administration of MDP reduced in vivo bacterial replication and thus improved lung pathology in M. abscessus-infected mice. This study offers important new insights into the potential roles of the NOD2 in initiating and potentiating innate immune response against M. abscessus pulmonary infection.

Safflower bud inhibits RANKL-induced osteoclast differentiation and prevents bone loss in ovariectomized mice.

BACKGROUND: The powder and extract of safflower seeds are known to be effective in the prevention of bone loss in ovariectomized animals. However, the inhibitory effect and molecular mechanisms of safflower bud (SB), the germinated safflower, on bone destruction is unclear. PURPOSE: The present study was designed to investigate the inhibitory effect and molecular mechanism of SB on osteoclastic differentiation and on bone loss in ovarietomized (OVX) mice. METHODS: Osteoclastogenesis was determined by TRAP staining, F-actin ring formation, and bone resorption assay. NF-κB and MAPKs activation was analyzed by transfection assay and Western blot, respectively. Real-time PCR was performed to examine the expression of osteoclastogenesis-related genes. Histological changes, increases in TRAP-positive cells, and cathepsin K expression were examined in the metaphysis of OVX mice. Density of bone marrow was evaluated by µCT. RESULTS: SB inhibited the RANKL-induced differentiation of BMDMs into osteoclasts in a dose-dependent manner. F-actin ring formation and bone resorption were also reduced by SB in RANKL-treated BMDMs. In addition, SB decreased the activation of NF-κB and MAPKs and the expression of osteoclastogenesis-related genes in BMDMs treated with RANKL. Feeding of SB-included diet prevented bone loss in OVX mice. The number of TRAP-positive cells and level of protein expression of cathepsin K was reduced and bone mineral density was increased in the metaphysis of mice fed SB compared with OVX mice. CONCLUSION: These findings suggest that SB can be a preventive and therapeutic candidate for destructive bone diseases.

Genetic alterations responsible for reduced susceptibility to vancomycin in community-associated MRSA strains of ST72.

Objectives: We previously reported the first case of vancomycin treatment failure due to development of vancomycin-intermediate resistance in a patient with an MRSA of ST72, a community genotype in Korea. We investigated two isogenic MRSA strains from this patient, who experienced treatment failure with vancomycin and rifampicin. Methods: We tracked the genetic alterations that confer reduced susceptibility to vancomycin on those two isogenic MRSA strains by WGS. Results: Five non-synonymous mutations were identified, including rpoB (H481Y), dprA (G196C), femA (F92C), vraR (E127K) and agrC (E391stop). We further studied the role of a mutation of vraR in reduced susceptibility to vancomycin. Introduction of the mutated vraR (E127K) into a vancomycin-susceptible Staphylococcus aureus strain resulted in an increase in vraSR mRNA expression and vancomycin MIC and development of the hetero-VISA phenotype, which was confirmed by the population analysis profile (PAP)/AUC. Electron microscopy showed increased cell wall thickness in the strains with mutated vraR. Conclusions: Based on the genomic data, molecular experiments and PAP and cell wall analyses, we propose that a single mutation of vraR is associated with the reduced susceptibility to vancomycin in MRSA and further treatment failure.

TLR2 contributes to trigger immune response of pleural mesothelial cells against Mycobacterium bovis BCG and M. tuberculosis infection.

Mycobacterium tuberculosis is a causative agent leading to pleural effusion, characterized by the accumulation of fluid and immune cells in the pleural cavity. Although this phenomenon has been described before, detailed processes or mechanisms associated with the pleural effusion are still not well understood. Pleural mesothelial cells (PMCs) are specialized epithelial cells that cover the body wall and internal organs in pleural cavity playing a central role in pleural inflammation. Toll-like receptors are expressed in various cell types including mesothelial cells and initiate the recognition and defense against mycobacterial infection. In the present study, we investigated direct immune responses of PMCs against two mycobacterial strains, M. bovis vaccine strain Bacille Calmette-Guérin (BCG) and M. tuberculosis virulent strain H37Rv, and the role of TLR2 in such responses. Infection with BCG and H37Rv increased the production of IL-6, CXCL1, and CCL2 in WT PMCs, which was partially impaired in TLR2-deficient cells. In addition, the activation of NF-κB and MAPKs induced by BCG and H37Rv was suppressed in TLR2-deficient PMCs, as compared with the WT cells. TLR2 deficiency led to the decrease of nitric oxide (NO) production through the delayed gene expression of iNOS in PMCs. TLR2 was also shown to be essential for optimal expression of cellular adhesion molecules such as ICAM-1 and VCAM-1 in PMCs in response to BCG and H37Rv. These findings strongly suggest that TLR2 participates in mycobacteria-induced innate immune responses in PMCs and may play a role in pathogenesis of tuberculosis pleural effusion.

Gamma-tocopherol supplementation ameliorated hyper-inflammatory response during the early cutaneous wound healing in alloxan-induced diabetic mice.

Delayed wound healing is one of the major diabetic complications. During wound healing process, the early inflammatory stage is important for better prognosis. One of antioxidant nutrient, gamma-tocopherol (GT) is considered to regulate inflammatory conditions. This study investigated the effect of GT supplementation on mechanism associated with inflammation, oxidative stress, and apoptosis during early cutaneous wound healing in diabetic mice. Diabetes was induced by alloxan injection in ICR mice. All mice were divided into three groups: non-diabetic control mice (CON), diabetic control mice (DMC), and diabetic mice supplemented with GT (GT). After two weeks of GT supplementation, excisional wounds were made by biopsy punches (4 mm). Diabetic mice showed increases in fasting blood glucose (FBG) level, hyper-inflammatory response, oxidative stress, and delayed wound closure rate compared to non-diabetic mice. However, GT supplementation reduced FBG level and accelerated wound closure rate by regulation of inflammatory response-related proteins such as nuclear factor kappa B, interleukin-1ß, tumor necrosis factor-α, and c-reactive protein, and oxidative stress-related markers including nuclear factor (erythroid derived 2)-like 2, NAD(P)H dehydrogenase quinone1, heme oxygenase-1, manganese superoxide dismutase, catalase and glutathione peroxidase and apoptosis-related markers such as sirtuin-1, peroxisome proliferator-activated receptor gamma coactivator 1- α, and p53 in diabetic mice. Taken together, GT would be a potential therapeutic to prevent diabetes-induced delayed wound healing by regulation of inflammatory response, apoptosis, and oxidative stress. Impact statement Gamma tocopherol has shown ameliorative effect on diabetic wound healing by regulation of inflammation, oxidative stress, and apoptosis demonstrated by nuclear factor kappa B, nuclear factor (erythroid derived 2)-like 2, and sirtuin-1.

Toll/IL-1 domain-containing adaptor inducing IFN-ß (TRIF) mediates innate immune responses in murine peritoneal mesothelial cells through TLR3 and TLR4 stimulation.

Mesothelial cells are composed of monolayer of the entire surface of serosal cavities including pleural, pericardial, and peritoneal cavity. Although mesothelial cells are known to express multiple Toll-like receptors (TLRs) which contribute to trigger innate immune responses against infections, the precise molecular mechanism remains still unclear. In the present study, we investigated the role of Toll/IL-1 domain-containing adaptor inducing IFN-ß (TRIF), one of the two major TLRs-adaptor molecules, on innate immune response induced by TLR3 and TLR4 stimulation in murine peritoneal mesothelial cells (PMCs). TRIF was strongly expressed in PMCs and its deficiency led to impaired production of cytokines and chemokines by poly I:C and LPS in the cells. Activation of NF-κB or MAPKs through poly I:C and LPS stimulation was reduced in TRIF-deficient PMCs as compared to the WT cells. TRIF was also necessary for optimal nitric oxide synthesis and gene expression of inducible nitric oxide synthase (iNOS) and IFN-ß in PMCs in response to poly I:C and LPS. Furthermore, both Escherichia coli and Pseudomonas aeruginosa induced high level of IL-6, CXCL1, and CCL2 production in PMCs, which was significantly impaired by TRIF deficiency. These results demonstrated that TRIF is required for optimal activation of innate immune responses in mesothelial cells against microbial infections.

Nicotinamide Riboside Ameliorates Hepatic Metaflammation by Modulating NLRP3 Inflammasome in a Rodent Model of Type 2 Diabetes.

Low-grade chronic inflammation (metaflammation) is a major contributing factor for the onset and development of metabolic diseases, such as type 2 diabetes, obesity, and cardiovascular disease. Nicotinamide riboside (NR), which is present in milk and beer, is a functional vitamin B3 having advantageous effects on metabolic regulation. However, the anti-inflammatory capacity of NR is unknown. This study evaluated whether NR modulates hepatic nucleotide binding and oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome. Male, 8-week-old KK/HlJ mice were allocated to the control or NR group. NR (100 mg/kg/day) or vehicle (phosphate-buffered saline) was administrated by an osmotic pump for 7 days. Glucose control, lipid profiles, NLRP3 inflammasome, and inflammation markers were analyzed, and structural and histological analyses were conducted. NR treatment did not affect body weight gain, food intake, and liver function. Glucose control based on the oral glucose tolerance test and levels of serum insulin and adiponectin was improved by NR treatment. Among tested lipid profiles, NR lowered the total cholesterol concentration in the liver. Histological and structural analysis by hematoxylin and eosin staining and transmission electron microscopy, respectively, showed that NR rescued the disrupted cellular integrity of the mitochondria and nucleus in the livers of obese and diabetic KK mice. In addition, NR treatment significantly improved hepatic proinflammatory markers, including tumor necrosis factor-alpha, interleukin (IL)-6, and IL-1. These ameliorations were accompanied by significant shifts of NLRP3 inflammasome components (NLRP3, ASC, and caspase1). These results demonstrate that NR attenuates hepatic metaflammation by modulating the NLRP3 inflammasome.

Characterization of a novel two-component regulatory system, HptRS, the regulator for the hexose phosphate transport system in Staphylococcus aureus.

Hexose phosphate is an important carbon source within the cytoplasm of host cells. Bacterial pathogens that invade, survive, and multiply within various host epithelial cells exploit hexose phosphates from the host cytoplasm through the hexose phosphate transport (HPT) system to gain energy and synthesize cellular components. In Escherichia coli, the HPT system consists of a two-component regulatory system (UhpAB) and a phosphate sensor protein (UhpC) that tightly regulate expression of a hexose phosphate transporter (UhpT). Although growing evidence suggests that Staphylococcus aureus also can invade, survive, and multiply within various host epithelial cells, the genetic elements involved in the HPT system in S. aureus have not been characterized yet. In this study, we identified and characterized the HPT system in S. aureus that includes the hptRS (a novel two-component regulatory system), the hptA (a putative phosphate sensor), and the uhpT (a hexose phosphate transporter) genes. The hptA, hptRS, and uhpT markerless deletion mutants were generated by an allelic replacement method using a modified pMAD-CM-GFPuv vector system. We demonstrated that both hptA and hptRS are required to positively regulate transcription of uhpT in response to extracellular phosphates, such as glycerol-3-phosphate (G3P), glucose-6-phosphate (G6P), and fosfomycin. Mutational studies revealed that disruption of the hptA, hptRS, or uhpT gene impaired the growth of bacteria when the available carbon source was limited to G6P, impaired survival/multiplication within various types of host cells, and increased resistance to fosfomycin. The results of this study suggest that the HPT system plays an important role in adaptation of S. aureus within the host cells and could be an important target for developing novel antistaphylococcal therapies.

Preventive effects of bitter melon (Momordica charantia) against insulin resistance and diabetes are associated with the inhibition of NF-κB and JNK pathways in high-fat-fed OLETF rats.

Bitter melon (BM; Momordica charantia) has been used as a treatment method for various diseases including cancer and diabetes. The objective of this study was to investigate whether BM has preventive effects against insulin resistance and diabetes and to identify the underlying mechanism by which BM ameliorates insulin resistance in obese and diabetic rats. The rats were separated into three groups as follows: (a) high-fat (HF) diet control, (b) HF diet and 1% BM and (c) HF diet and 3% BM. After 6 weeks of assigned treatments, body weight and food intake were not altered by BM administration. Bitter melon treatment significantly improved glucose tolerance and insulin sensitivity. The levels of proinflammatory cytokines were significantly down-regulated in liver, muscle and epididymal fats from BM-treated rats. The activation of nuclear factor-κB (NF-κB) in the liver and muscle was decreased by BM compared with HF controls. The 3% BM supplementation significantly increased the levels of phospho-insulin receptor substrate-1 (Tyr612) and phospho-Akt (Ser473). It also significantly decreased the levels of phospho-NF-κB (p65) (Ser536) and phospho-c-Jun N-terminal kinase (JNK) (Thr183/Tyr185) in liver, muscle and epididymal fats. The findings of this study indicate that BM exerted preventive effects against insulin resistance and diabetes through the modulation of NF-κB and JNK pathways. Therefore, BM may be useful in the prevention of insulin resistance and diabetes.