Inflammatory cytokines in general and central obesity and modulating effects of physical activity

Targeting Neuroinflammation to Treat Alzheimer's Disease

Over the past few decades, research on Alzheimer's disease (AD) has focused on pathomechanisms linked to two of the major pathological hallmarks of extracellular deposition of beta-amyloid peptides and intra-neuronal formation of neurofibrils. Recently, a third disease component, the neuroinflammatory reaction mediated by cerebral innate immune cells, has entered the spotlight, prompted by findings from genetic, pre-clinical, and clinical studies. Various proteins that arise during neurodegeneration, including beta-amyloid, tau, heat shock proteins, and chromogranin, among others, act as danger-associated molecular patterns, that-upon engagement of pattern recognition receptors-induce inflammatory signaling pathways and ultimately lead to the production and release of immune mediators. These may have beneficial effects but ultimately compromise neuronal function and cause cell death. The current review, assembled by participants of the Chiclana Summer School on Neuroinflammation 2016, provides an overview of our current understanding of AD-related immune processes. We describe the principal cellular and molecular players in inflammation as they pertain to AD, examine modifying factors, and discuss potential future therapeutic targets.

Challenges in simulating the human gut for understanding the role of the microbiota in obesity

There is an elevated incidence of cases of obesity worldwide. Therefore, the development of strategies to tackle this condition is of vital importance. This review focuses on the necessity of optimising in vitro systems to model human colonic fermentation in obese subjects. This may allow to increase the resolution and the physiological relevance of the information obtained from this type of studies when evaluating the potential role that the human gut microbiota plays in obesity. In light of the parameters that are currently used for the in vitro simulation of the human gut (which are mostly based on information derived from healthy subjects) and the possible difference with an obese condition, we propose to revise and improve specific standard operating procedures.

Impact of Serum Cytokine Levels on EEG-Measured Arousal Regulation in Patients with Major Depressive Disorder and Healthy Controls

BACKGROUND

In major depressive disorder (MDD), findings include hyperstable regulation of brain arousal measured by electroencephalography (EEG) vigilance analysis and alterations in serum levels of cytokines. It is also known that cytokines affect sleep-wake regulation. This study investigated the relationship between cytokines and EEG vigilance in participants with MDD and nondepressed controls, and the influence of cytokines on differences in vigilance between the two groups.

METHODS

In 60 patients with MDD and 129 controls, 15-min resting-state EEG recordings were performed and vigilance was automatically assessed with the VIGALL 2.0 (Vigilance Algorithm Leipzig). Serum levels of the wakefulness-promoting cytokines interleukin (IL)-4, IL-10, IL-13 and somnogenic cytokines tumor necrosis factor-α, interferon-x03B3; and IL-2 were measured prior to the EEG.

RESULTS

Summed wakefulness-promoting cytokines, but not somnogenic cytokines, were significantly associated with the time course of EEG vigilance in the MDD group only. In both groups, IL-13 was significantly associated with the course of EEG vigilance. In MDD compared to controls, a hyperstable EEG vigilance regulation was found, significant for group and group × time course interaction. After controlling for wakefulness-promoting cytokines, differences in vigilance regulation between groups remained significant.

CONCLUSIONS

The present study demonstrated a relationship between wakefulness-promoting cytokines and objectively measured EEG vigilance as an indicator for brain arousal. Altered brain arousal regulation in MDD gives support for future evaluation of vigilance measures as a biomarker in MDD. Since interactions between cytokines and EEG vigilance only moderately differed between the groups and cytokine levels could not explain the group differences in EEG vigilance regulation, cytokines and brain arousal regulation are likely to be associated with MDD in independent ways.

Serum from obstructive sleep apnea patients induces inflammatory responses in coronary artery endothelial cells

BACKGROUND AND AIMS

Obstructive sleep apnea (OSA) is characterized by intermittent airway obstruction and systemic hypoxia during sleep, which can contribute to an increase in reactive oxygen species, vascular remodeling, vasoconstriction and ultimately cardiovascular disease. Continuous positive airway pressure (CPAP) is a clinical therapy that maintains airway patency and mitigates several symptoms of OSA. However, it is currently unknown whether CPAP therapy also reduces the overall inflammatory potential in the circulation; to address this in an unbiased manner, we applied a novel endothelial biosensor approach, the serum cumulative inflammatory potential (SCIP) assay.

METHODS

We studied healthy controls (n = 7), OSA subjects receiving no treatment, (OSA controls) (n = 7) and OSA subjects receiving CPAP for 3 months (n = 8). Serum was obtained from OSA subjects before and after CPAP or no treatment. A battery of quantitative and functional assays was performed to assess the serum inflammatory potential, in terms of endothelial responses. For the SCIP assay, human coronary artery endothelial cells (hCAECs) were incubated with 5% serum in media from individual subjects for 4 h. qPCR was performed to assess endothelial inflammatory transcript (ICAM-1, VCAM-1, IL-8, P-selectin, CCL5, and CXCL12) responses to serum. Additionally, transendothelial resistance was measured in serum-incubated hCAECs following leukocyte challenge.

RESULTS

hCAECs exhibited significant increases in VCAM-1, ICAM-1, IL-8 and P-selectin mRNA when incubated with serum from OSA patients compared to serum from healthy control subjects. Furthermore, compared to no treatment, serum from CPAP-treated individuals was less potent at inducing inflammatory gene expression in the SCIP assay. Similarly, in a leukocyte adhesion assay, naïve cells treated with serum from patients who received CPAP exhibited improved endothelial barrier function than cells treated with OSA control serum.

CONCLUSIONS

OSA results in greater serum inflammatory potential, thereby driving endothelial activation and dysfunction.

Metabolic risk factors and mechanisms of disease in epithelial ovarian cancer: A review

OBJECTIVE

Epithelial ovarian cancer continues to be the deadliest gynecologic malignancy. Patients with both diabetes mellitus and obesity have poorer outcomes, yet research correlating metabolic abnormalities, such as metabolic syndrome, to ovarian cancer risk and outcomes is lacking. This article reviews the literature regarding metabolic derangements and their relationship to epithelial ovarian cancer, with a focus on potential mechanisms behind these associations.

METHODS

PubMed and Google Scholar were searched for articles in the English language regarding epithelial ovarian cancer, obesity, diabetes mellitus, and metabolic syndrome, with a focus on studies conducted since 1990.

RESULTS

Obesity, type II diabetes mellitus, and metabolic syndrome have been associated with poor outcomes in epithelial ovarian cancer. More studies investigating the relationship between metabolic syndrome and epithelial ovarian cancer are needed. A variety of pathologic factors may contribute to cancer risk in patients with metabolic derangements, including altered adipokine and cytokine expression, altered immune responses to tumor cells, and changes in pro-tumorigenic signaling pathways.

CONCLUSION

More research is needed to examine the effects of metabolic syndrome on epithelial ovarian cancer risk and mortality, as well as the underlying pathophysiologies in patients with obesity, diabetes mellitus, and metabolic syndrome that may be targeted for therapeutic intervention.

Cytokine profiles in overweight and obese subjects and normal weight individuals matched for age and gender

Background Obesity is associated with a state of systemic inflammation, mediated by adipose tissue-derived cytokines that may also have metabolic effects, including an effect on insulin resistance. The aim of this study was to compare the serum profile of pro- and anti-inflammatory cytokines in obese and non-obese subjects. Methods A total of 242 subjects who were either overweight or obese (body mass index [BMI] ≥ 25 kg/m²) and non-obese subjects (body mass index <25 kg/m²), were recruited in Mashhad in northeastern Iran. The concentrations of serum interleukin-1α, -1β, -2, -4, -6, -8 and -10 (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8 and IL-10), were measured in all subjects, together with serum vascular endothelial growth factor, interferon-γ, epidermal growth factor, monocyte chemoattractant protein-1 and tumour necrosis factor-α. Results The groups differed significantly with respect to measures of adiposity and fasted lipid profile. Serum pro-inflammatory cytokines interferon-γ and interleukin-1α, and anti-inflammatory cytokines, interleukin-10, and epidermal growth factor were significantly different between obese and non-obese individuals, as was serum high-sensitivity C-reactive protein. Multivariate regression showed that waist circumference was significantly and independently related to serum monocyte chemoattractant protein-1concentrations ( P = 0.001). Conclusion Despite significant differences in several cytokines between the groups, only monocyte chemoattractant protein-1appeared to be independently related to a measure of adiposity in this population sample from Iran.

Immunomodulatory roles of CTRP3 in endotoxemia and metabolic stress

C1q/TNF‐related protein 3 (CTRP3) is a secreted hormone that modulates hepatic glucose and lipid metabolism. Its circulating levels are reduced in human and rodent models of obesity, a metabolic state accompanied by chronic low‐grade inflammation. Recent studies have demonstrated an anti‐inflammatory role for recombinant CTRP3 in attenuating LPS‐induced systemic inflammation, and its deficiency markedly exacerbates inflammation in a mouse model of rheumatoid arthritis. We used genetic mouse models to explore the immunomodulatory function of CTRP3 in response to acute (LPS challenge) and chronic (high‐fat diet) inflammatory stimuli. In a sublethal dose of LPS challenge, neither CTRP3 deficiency nor its overexpression in transgenic mice had an impact on IL‐1β, IL‐6, TNF‐α, or MIP‐2 induction at the serum protein or mRNA levels, contrary to previous findings based on recombinant CTRP3 administration. In a metabolic context, we measured 71 serum cytokine levels in wild‐type and CTRP3 transgenic mice fed a high‐fat diet or a matched control low‐fat diet. On a low‐fat diet, CTRP3 transgenic mice had elevated circulating levels of multiple chemokines (CCL11, CXCL9, CXCL10, CCL17, CX3CL1, CCL22 and sCD30). However, when obesity was induced with a high‐fat diet, CTRP3 transgenic mice had lower circulating levels of IL‐5, TNF‐α, sVEGF2, and sVEGFR3, and a higher level of soluble gp130. Contingent upon the metabolic state, CTRP3 overexpression altered chemokine levels in lean mice, and attenuated systemic inflammation in the setting of obesity and insulin resistance. These results highlight a context‐dependent immunomodulatory role for CTRP3.

Long-term chemotherapy-induced peripheral neuropathy among breast cancer survivors: prevalence, risk factors, and fall risk

Chemotherapy-induced peripheral neuropathy (CIPN) is a common toxicity associated with chemotherapy, but researchers rarely study its risk factors, fall risk, and prevalence in long-term breast cancer survivors. We aimed to determine CIPN prevalence, risk factors, and association with psychological distress and falls among long-term breast cancer survivors. We conducted Cross-sectional analyses among postmenopausal women with a history of stage I-III breast cancer who received taxane-based chemotherapy. Participants reported neuropathic symptoms of tingling/numbness in hands and/or feet on a 0-10 numerical rating scale. We conducted multivariate logistic regression analyses to evaluate risk factors associated with the presence of CIPN and the relationship between CIPN and anxiety, depression, insomnia, and patient-reported falls. Among 296 participants, 173 (58.4 %) reported CIPN symptoms, 91 (30.7 %) rated their symptoms as mild, and 82 (27.7 %) rated them moderate to severe. Compared with women of normal weight, being obese was associated with increased risk of CIPN (adjusted OR 1.94, 95 % CI: 1.03-3.65). Patients with CIPN reported greater insomnia severity, anxiety, and depression than those without (all p < 0.05). Severity of CIPN was associated with higher rates of falls, with 23.8, 31.9, and 41.5 % in the "no CIPN," "mild," and "moderate-to-severe" groups, respectively, experiencing falls (p = 0.028). The majority of long-term breast cancer survivors who received taxane-based chemotherapy reported CIPN symptoms; obesity was a significant risk factor. Those with CIPN also reported increased psychological distress and falls. Interventions need to target CIPN and comorbid psychological symptoms, and incorporate fall prevention strategies for aging breast cancer survivors.

Emodin Decreases Hepatic Hypoxia-Inducible Factor-1[Formula: see text] by Inhibiting its Biosynthesis

Hypoxia-inducible factor-1 (HIF-1) is an [Formula: see text] dimeric transcription factor. Because HIF-1[Formula: see text] is instable with oxygen, HIF-1 is scarce in normal mammalian cells. However, HIF-1[Formula: see text] is expressed in pathological conditions such as cancer and obesity. Inhibiting HIF-1[Formula: see text] may be of therapeutic value for these pathologies. Here, we investigated whether emodin, derived from the herb of Rheum palmatum L, which is also known as Chinese rhubarb, and is native to China, regulates HIF-1[Formula: see text] expression. Male C57BL/6 mice without or with diet-induced obesity were treated with emodin for two weeks, while control mice were treated with vehicle. HIF-1[Formula: see text] expression was determined by Western blot. We found that emodin inhibited obesity-induced HIF-1[Formula: see text] expression in liver and skeletal muscle but did not regulate HIF-1[Formula: see text] expression in the kidneys or in intra-abdominal fat. In vitro, emodin inhibited HIF-1[Formula: see text] expression in human HepG2 hepatic cells and Y1 adrenocortical cells. Further, we investigated the mechanisms of HIF-1[Formula: see text] expression in emodin-treated HepG2 cells. First, we found that HIF-1[Formula: see text] had normal stability in the presence of emodin. Thus, emodin did not decrease HIF-1[Formula: see text] by stimulating its degradation. Importantly, emodin decreased the activity of the signaling pathways that led to HIF-1[Formula: see text] biosynthesis. Interestingly, emodin increased HIF-1[Formula: see text] mRNA in HepG2 cells. This may be a result of feedback in response to the emodin-induced decrease in the protein of HIF-1[Formula: see text]. In conclusion, emodin decreases hepatic HIF-1[Formula: see text] by inhibiting its biosynthesis.

Abdominal Obesity and Type 2 Diabetes Mellitus are Associated With Higher Seric Levels of IL 4 in Adults

Aims: Study of IL4 in relation to the anthropometric, biochemical and immunological parameters in patients with obesity and/or diabetes. Methods: The relationship between IL4 and clinical and biological parameters was studied in 76 patients divided into 4 groups: obese diabetics (OD), n = 25; obese without diabetes (O), n = 25; non obese diabetics (NOD), n = 11; controls (M), n = 15. IL4 was determined using the ELISA method. Statistical analysis was done using the MedCalc statistical software, version 16.1. Results: Serum IL4 was 0.38 ±0,40 pg / mL in the Control group, 0.366 (0,100-2,35) pg / ml in group O, 4.66±3.73 pg / ml in group OD, 0.30 (0.10-1.35) pg / ml in NOD. When IL4 levels were compared between the four groups, statistical significance was reached for the comparison between groups OD and M. Statistically significant correlations were detected between IL4 and age, waist circumference and hip circumference, blood glucose, glycated hemoglobin (HbA1c), VLDL, triglycerides and serum protein fraction β1. In univariate regression, the IL4 level predictors were age, height, BMI, abdominal circumference, hip circumference, beta 1% glucose, HbA1c, total lipids, total cholesterol, VLDL triglycerides, CRP. In multivariate regression, waist circumference and glycemia were significant predictors of levels of IL4 (p = 0.0001).

The Statistical Value of Raw Fluorescence Signal in Luminex xMAP Based Multiplex Immunoassays

Tissue samples (plasma, saliva, serum or urine) from 169 patients classified as either normal or having one of seven possible diseases are analysed across three 96-well plates for the presences of 37 analytes using cytokine inflammation multiplexed immunoassay panels. Censoring for concentration data caused problems for analysis of the low abundant analytes. Using fluorescence analysis over concentration based analysis allowed analysis of these low abundant analytes. Mixed-effects analysis on the resulting fluorescence and concentration responses reveals a combination of censoring and mapping the fluorescence responses to concentration values, through a 5PL curve, changed observed analyte concentrations. Simulation verifies this, by showing a dependence on the mean florescence response and its distribution on the observed analyte concentration levels. Differences from normality, in the fluorescence responses, can lead to differences in concentration estimates and unreliable probabilities for treatment effects. It is seen that when fluorescence responses are normally distributed, probabilities of treatment effects for fluorescence based t-tests has greater statistical power than the same probabilities from concentration based t-tests. We add evidence that the fluorescence response, unlike concentration values, doesn’t require censoring and we show with respect to differential analysis on the fluorescence responses that background correction is not required.

Pro- and anti-inflammatory cytokines, but not CRP, are inversely correlated with severity and symptoms of major depression

To clarify findings of elevated cytokine levels in major depression (MD), this study aimed to investigate the relationship between serum levels of cytokines, symptoms of MD and antidepressant treatment outcome. At baseline (T0) and 4 weeks following initiation of antidepressant treatment (T1), levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12, IL-13, granulocyte-macrophage-colony-stimulating-factor (GM-CSF), CRP and depression ratings HAMD-17 and BDI-II were assessed in 30 patients with MD and 30 age-and sex-matched controls. At T0, in the patient group, cytokines, but not CRP, negatively correlated with individual BDI-II-items, factors and severities and showed both negative and positive correlations with HAMD-17 items. At T1 and within the controls, no such relationships were observed. At T0 and T1, levels of both pro- and anti-inflammatory cytokines were significantly higher in treatment responders (ΔHAMD-17T0-T1≥50%,n=15) compared to non-responders. When controlled for baseline BDI, differences between groups were only found significant for IL-2 at T0. The results suggest cytokines are not generally pro-depressive but rather relate to more specific regulation of symptoms and severities in MD. Together with the association between cytokines and treatment responder status, these data support cytokines as a promising but still controversial biomarker of depression.

Increased depression and metabolic risk in postmenopausal breast cancer survivors

OBJECTIVE

Breast cancer survivors (BCS) are at high risk for the development of obesity, type 2 diabetes mellitus, and metabolic syndrome. There is increasing interest in the association between depression and metabolic dysfunction, which is relevant in this population as depression is often present in the chronic phase of cancer recovery. Thus, the aim of this study was to evaluate metabolic risk in BCS with and without depression compared to non-cancer controls.

METHODS

African American (46 %) and Caucasian (54 %) postmenopausal BCS (N = 28; age: 60 ± 2 years; mean ± SEM) were matched for race, age (±2 years), and BMI (±2 kg/m(2)) to non-cancer controls (N = 28). Center for Epidemiologic Studies Depression Scale (CES-D) >16 or antidepressant medication usage was used to classify depression. Metabolic status was defined by 2-hr glucose during an OGTT and classification of metabolic syndrome.

RESULTS

Compared to non-cancer controls, BCS had similar 2-hr glucose, but higher fasting glucose and total cholesterol, and were 2.5 times more likely to have metabolic syndrome (21 vs. 52 %)(P's < 0.05). Conversely, HDL-C was 16 % higher in BCS (P < 0.05). Forty three % of BCS were on antidepressants compared to 14 % in non-cancer controls, despite similar mean CES-D scores (6 ± 1). Depressed BCS (46 %) had a higher BMI, waist circumference, fasting glucose, and more metabolic syndrome components than non-depressed BCS (P's < 0.05).

CONCLUSIONS

BCS have a heightened prevalence of depression that may be associated with an increased prevalence of metabolic syndrome. These results support the need to monitor weight gain, depression, and the progression of metabolic abnormalities after cancer diagnosis and treatment. Further studies into the mechanistic link between depression and metabolic disease are necessary to identify strategies that can offset their impact on obesity and associated cardiovascular risk following a breast cancer diagnosis.

Increased C-reactive protein and decreased Interleukin-2 content in serum from obese individuals with or without insulin resistance: Associations with leukocyte count and insulin and adiponectin content

AIMS

Chronic inflammation in obesity is associated with co-morbidities such as, hyperglycemia, hypertension and hyperlipidemia. Leukocytes play an important role in this inflammation and C-reactive protein (CRP) and Interleukin-2 (IL-2) can be important effectors during the immune response in obesity; however, the initial inflammatory events in obesity remain unclear. The aim of this study was to determine the circulating levels of CRP, IL-2, insulin and adiponectin, their association and the association with leukocyte count in obese individuals without co-morbidities and with or without insulin resistance (IR).

MATERIALS AND METHODS

Nineteen obese non-diabetic and 9 lean subjects were studied for serum levels of CRP, IL-2, insulin, adiponectin, lipids, glycated hemoglobin, glycemia, for homeostasis model assessment of insulin resistance (HOMA-IR), arterial pressure and anthropometric parameters, and for leukocyte counts. Neutrophil/lymphocyte ratio (N/L) was calculated using the loge of leukocyte counts. Associations were determined by Pearson's correlation.

RESULTS

None of the studied groups presented co-morbidities and two groups of obese individuals with normal or high levels of insulin (IR) were found. Increased CRP concentration and decreased IL-2 and adiponectin concentrations in obese were observed. Positive correlation between leukocyte type counts with CRP in obese with IR was found; however, no correlations with IL-2 in obese were observed. Insulin in obese were positively correlated with CRP and negatively correlated with IL-2 in IR obese individuals. Adiponectin in obese was negatively correlated with CRP.

CONCLUSION

CRP and IL-2 may represent two important effectors in the early inflammatory events in obese individuals without co-morbidities. Adiponectin and insulin may be involved in anti-inflammatory events.

Síndrome metabólica, aterosclerose e inflamação: tríade indissociável?

Resumo Observa-se, nas populações mundiais, aumento do sedentarismo e aumento do consumo de gorduras e açúcares, sendo estes vinculados normalmente aos alimentos industrializados. A consequência disso rapidamente se manifestou no aumento do sobrepeso/obesidade e na instalação de alterações fisiológicas e metabólicas, como a Síndrome Metabólica, que é representada por alterações na glicemia, nos lipídeos e na pressão arterial. Há evidências de ligação estreita entre estas alterações e os processos inflamatórios, que também podem estar associados ao estresse oxidativo. Estas condições levam à patogênese das alterações vasculares ou intensificam os processos metabólicos que acompanham a Síndrome Metabólica. O objetivo desta revisão foi comparar as inúmeras referências literárias que mostram correlação entre os componentes da Síndrome Metabólica e o aumento dos mediadores de inflamação. Para isso, utilizou-se Pubmed, Scopus, Lilacs e Scielo como base de dados, sendo que os artigos selecionados dataram principalmente dos últimos cinco anos.

High intensity interval exercise decreases IL-8 and enhances the immunomodulatory cytokine interleukin-10 in lean and overweight-obese individuals

PURPOSE

To compare the effects of two interval exercises with different intensities on acute inflammatory response in lean and overweight-obese subjects.

METHODS

Ten lean (BMI<24.9kg/m(2)) and 12 overweight-obese (BMI 25 to <34.9kg/m(2)) males performed two conditions in randomly assigned: (1) high intensity interval exercise (HIIE) 10×60s (85-90%PMax)/75s (50%PMax); (2) moderate intensity interval exercise (MIIE) 10×60s (70-75%PMax)/60s (50%PMax), with blood collections at pre, immediately and 30min post each exercise bouts to evaluate total and differential leukocyte counts, serum creatine kinase (CK), lactate dehydrogenase (LDH) and systemic levels of IL-1ra, IL-6, IL-8, IL-10, IL-17a and CCL2.

RESULTS

In lean group, HIIE induced a significant increase in total leukocytes and monocyte, while MIIE session did not change the number of leukocytes. Overweight-obese group presented similar increase in leukocytes, monocytes and lymphocytes in both HIIE and MIIE sessions. At baseline, overweight-obese group showed high levels of CK, IL-8, IL-6 and CCL2 and lower concentrations of IL-10 compared to lean group. The MIIE did not alter the cytokine concentrations in both groups, independently of the time analysis. The HIIE induced significant decrease in IL-8 levels 30min post session in both the groups, and a progressive elevation in IL-10 levels immediately and 30min post in lean and overweight-obese. Regarding IL-6, overweight-obese subjects presented progressive increase either immediately and 30min after HIIE, while lean individuals presented significant increase only 30min after exercise.

CONCLUSIONS

The acute inflammatory response to interval exercise is intensity-dependent. Although obesity influences the basal concentrations of several cytokines, only HIIE induced important alterations in IL-8 and IL-10 levels, which may have important implications in the control of chronic low-grade inflammation in obesity.

Weight Loss, Dietary Intake and Pulse Wave Velocity

We have recently conducted a meta-analysis to determine the effect of weight loss achieved by an energy-restricted diet with or without exercise, anti-obesity drugs or bariatric surgery on pulse wave velocity (PWV) measured at all arterial segments. Twenty studies, including 1,259 participants, showed that modest weight loss (8% of the initial body weight) caused a reduction in PWV measured at all arterial segments. However, due to the poor methodological design of the included studies, the results of this meta-analysis can only be regarded as hypothesis generating and highlight the need for further research in this area. In the future, well-designed randomised controlled trials are required to determine the effect of diet-induced weight loss on PWV and the mechanisms involved. In addition, there is observational evidence that dietary components such as fruit, vegetables, dairy foods, sodium, potassium and fatty acids may be associated with PWV, although evidence from well-designed intervention trials is lacking. In the future, the effect of concurrently improving dietary quality and achieving weight loss should be assessed in randomised controlled trials.

Class II transactivator (CIITA) mediates transcriptional repression of pdk4 gene by interacting with hypermethylated in cancer 1 (HIC1)

Increased accumulation and/or impaired utilization of fatty acid in extra-adipose tissues are implicated in the pathogenesis of insulin resistance and type 2 diabetes. Pyruvate dehydrogenase kinase 4 (Pdk4) is a key enzyme involved in fatty oxidation and energy expenditure, and its expression can be repressed by pro-inflammatory stimuli. Previously, we have shown that class II transactivator (CIITA) mediates the adverse effect of interferon gamma (IFN-γ) in skeletal muscle cells by cooperating with hypermethylated in cancer 1 (HIC1) to repress silent information regulator 1 (SIRT1) transcription. Building upon this finding, we report here that CIITA interacted with HIC1 via the GTP-binding domain (GBD) while HIC1 interacted with CIITA via the BTB/POZ domain. The GBD domain was required for CIITA to repress SIRT1 transcription probably acting as a bridge for CIITA to bind to HIC1 and consequently to bind to the SIRT1 promoter. IFN-γ stimulation, CIITA over-expression, or HIC1 over-expression repressed Pdk4 promoter activity while silencing either CIITA or HIC1 normalized Pdk4 expression in the presence of IFN-γ. An increase in SIRT1 expression or activity partially rescued Pdk4 expression in the presence of CIITA, but SIRT1 inhibition abrogated Pdk4 normalization even in the absence of CIITA. Taken together, our data have identified a HIC1-CIITA-SIRT1 axis that regulates Pdk4 transcription in response to IFN-γ stimulation.