The Dual-Specificity Phosphatase 2 (DUSP2) Does Not Regulate Obesity-Associated Inflammation or Insulin Resistance in Mice

Alterations in the immune cell profile and the induction of inflammation within adipose tissue are a hallmark of obesity in mice and humans. Dual-specificity phosphatase 2 (DUSP2) is widely expressed within the immune system and plays a key role promoting immune and inflammatory responses dependent on mitogen-activated protein kinase (MAPK) activity. We hypothesised that the absence of DUSP2 would protect mice against obesity-associated inflammation and insulin resistance. Accordingly, male and female littermate mice that are either wild-type (wt) or homozygous for a germ-line null mutation of the dusp2 gene (dusp2^−/−) were fed either a standard chow diet (SCD) or high fat diet (HFD) for 12 weeks prior to metabolic phenotyping. Compared with mice fed the SCD, all mice consuming the HFD became obese, developed glucose intolerance and insulin resistance, and displayed increased macrophage recruitment and markers of inflammation in epididymal white adipose tissue. The absence of DUSP2, however, had no effect on the development of obesity or adipose tissue inflammation. Whole body insulin sensitivity in male mice was unaffected by an absence of DUSP2 in response to either the SCD or HFD; however, HFD-induced insulin resistance was slightly, but significantly, reduced in female dusp2^−/− mice. In conclusion, DUSP2 plays no role in regulating obesity-associated inflammation and only a minor role in controlling insulin sensitivity following HFD in female, but not male, mice. These data indicate that rather than DUSP2 being a pan regulator of MAPK dependent immune cell mediated inflammation, it appears to differentially regulate inflammatory responses that have a MAPK component.     

An Apolipoprotein A-I Mimetic Peptide Designed with a Reductionist Approach Stimulates Reverse Cholesterol Transport and Reduces Atherosclerosis in Mice

Apolipoprotein A-I (apoA-I) mimetic peptides are considered a promising novel therapeutic approach to prevent and/or treat atherosclerosis. An apoA-I mimetic peptide ELK-2A2K2E was designed with a reductionist approach and has shown exceptional activity in supporting cholesterol efflux but modest anti-inflammatory and anti-oxidant properties in vitro. In this study we compared these in vitro properties with the capacity of this peptide to modify rates of reverse cholesterol transport and development of atherosclerosis in mouse models. The peptide enhanced the rate of reverse cholesterol transport in C57BL/6 mice and reduced atherosclerosis in Apoe^−/− mice receiving a high fat diet. The peptide modestly reduced the size of the plaques in aortic arch, but was highly active in reducing vascular inflammation and oxidation. Administration of the peptide to Apoe^−/− mice on a high fat diet reduced the levels of total, high density lipoprotein and non-high density lipoprotein cholesterol and triglycerides. It increased the proportion of smaller HDL particles in plasma at the expense of larger HDL particles, and increased the capacity of the plasma to support cholesterol efflux. Thus, ELK-2A2K2E peptide reduced atherosclerosis in Apoe^−/− mice, however, the functional activity profile after chronic in vivo administration was different from that found in acute in vitro studies.     

Dim Light at Night Does Not Disrupt Timing or Quality of Sleep in Mice

Artificial nighttime illumination has recently become commonplace throughout the world; however, in common with other animals, humans have not evolved in the ecological context of chronic light at night. With prevailing evidence linking the circadian, endocrine, immune, and metabolic systems, understanding these relationships is important to understanding the etiology and progression of several diseases. To eliminate the covariate of sleep disruption in light at night studies, researchers often use nocturnal animals. However, the assumption that light at night does not affect sleep in nocturnal animals remains unspecified. To test the effects of light at night on sleep, we maintained Swiss-Webster mice in standard light/dark (LD) or dim light at night (DLAN) conditions for 8–10 wks and then measured electroencephalogram (EEG) and electromyogram (EMG) biopotentials via wireless telemetry over the course of two consecutive days to determine differences in sleep timing and homeostasis. Results show no statistical differences in total percent time, number of episodes, maximum or average episode durations in wake, slow-wave sleep (SWS), or rapid eye movement (REM) sleep. No differences were evident in SWS delta power, an index of sleep drive, between groups. Mice kept in DLAN conditions showed a relative increase in REM sleep during the first few hours after the dark/light transition. Both groups displayed normal 24-h circadian rhythms as measured by voluntary running wheel activity. Groups did not differ in body mass, but a marked negative correlation of body mass with percent time spent awake and a positive correlation of body mass with time spent in SWS was evident. Elevated body mass was also associated with shorter maximum wake episode durations, indicating heavier animals had more trouble remaining in the wake vigilance state for extended periods of time. Body mass did not correlate with activity levels, nor did activity levels correlate with time spent in different sleep states. These data indicate that heavier animals tend to sleep more, potentially contributing to further weight gain. We conclude that chronic DLAN exposure does not significantly affect sleep timing or homeostasis in mice, supporting the use of dim light with nocturnal rodents in chronobiology research to eliminate the possible covariate of sleep disruption.     

研究: 载脂蛋白E拟肽EpK对apoE-/-小鼠动脉粥样硬化的影响

前期设计合成了一种模拟人载脂蛋白E(apoE)结构域的小分子多肽EpK,体外实验证实该拟肽具有抑制巨噬细胞炎症及增强高密度脂蛋白(HDL)介导细胞胆固醇外流的作用．本文拟借助慢病毒体系分泌性表达EpK,研究EpK在体对apoE基因敲除(apoE^-/-)小鼠动脉粥样硬化斑块的影响．将11月龄雌性apoE^-/-小鼠18只,随机分两组,分别经眼球后静脉丛注射pWPI慢病毒(Lv-GFP对照组)和含EpK的重组慢病毒(Lv-EpK组)．小鼠普食喂养,间隔采血监测血脂状态,检测血浆对氧磷酯酶(PON1)活性,病毒注射18周后小鼠安乐死,从主动脉根部连续冰冻切片及主动脉胸腹段纵剖面(en face)进行油红O染色分析斑块面积,采用实时荧光定量PCR检测小鼠肝脏相关基因的mRNA表达水平,蛋白质印迹检测血浆中apoA-Ⅰ、PON1及血清淀粉样蛋白A(SAA)水平．结果显示：慢病毒感染小鼠可成功在血循环中检测到EpK,与Lv-GFP对照组比较,Lv-EpK组apoE^-/-小鼠的血脂及脂蛋白分布、apoA-Ⅰ水平、PON1活性无明显改变,但EpK组小鼠的主动脉斑块面积较对照组显著减少(主动脉根部斑块面积(0.87±0.07) mm² vs (1.03±0.08) mm²,P < 0.05;主动脉胸腹段斑块占管腔比42.0% vs 55.8%,P < 0.01)．EpK可显著降低血中SAA水平,并抑制肝脏炎症因子TNF?琢和IL-6的表达．结果说明,EpK拟肽具有减退apoE^-/-小鼠动脉粥样硬化斑块的作用,其机制可能与其发挥的抗炎作用有关．     

Depletion of Endothelial or Smooth Muscle Cell-Specific Angiotensin II Type 1a Receptors Does Not Influence Aortic Aneurysms or Atherosclerosis in LDL Receptor Deficient Mice

Background

Whole body genetic deletion of AT1a receptors in mice uniformly reduces hypercholesterolemia and angiotensin II-(AngII) induced atherosclerosis and abdominal aortic aneurysms (AAAs). However, the role of AT1a receptor stimulation of principal cell types resident in the arterial wall remains undefined. Therefore, the aim of this study was to determine whether deletion of AT1a receptors in either endothelial cells or smooth muscle cells influences the development of atherosclerosis and AAAs.

Methodology/Principal Findings

AT1a receptor floxed mice were developed in an LDL receptor −/− background. To generate endothelial or smooth muscle cell specific deficiency, AT1a receptor floxed mice were bred with mice expressing Cre under the control of either Tie2 or SM22, respectively. Groups of males and females were fed a saturated fat-enriched diet for 3 months to determine effects on atherosclerosis. Deletion of AT1a receptors in either endothelial or smooth muscle cells had no discernible effect on the size of atherosclerotic lesions. We also determined the effect of cell-specific AT1a receptor deficiency on atherosclerosis and AAAs using male mice fed a saturated fat-enriched diet and infused with AngII (1,000 ng/kg/min). Again, deletion of AT1a receptors in either endothelial or smooth muscle cells had no discernible effects on either AngII-induced atherosclerotic lesions or AAAs.

Conclusions

Although previous studies have demonstrated whole body AT1a receptor deficiency diminishes atherosclerosis and AAAs, depletion of AT1a receptors in either endothelial or smooth muscle cells did not affect either of these vascular pathologies.     

Deficiency of Thrombospondin-4 in Mice Does Not Affect Skeletal Growth or Bone Mass Acquisition,but Causes a Transient Reduction of Articular Cartilage Thickness

Although articular cartilage degeneration represents a major public health problem, the underlying molecular mechanisms are still poorly characterized. We have previously utilized genome-wide expression analysis to identify specific markers of porcine articular cartilage, one of them being Thrombospondin-4 (Thbs4). In the present study we analyzed Thbs4 expression in mice, thereby confirming its predominant expression in articular cartilage, but also identifying expression in other tissues, including bone. To study the role of Thbs4 in skeletal development and integrity we took advantage of a Thbs4-deficient mouse model that was analyzed by undecalcified bone histology. We found that Thbs4-deficient mice do not display phenotypic differences towards wildtype littermates in terms of skeletal growth or bone mass acquisition. Since Thbs4 has previously been found over-expressed in bones of Phex-deficient Hyp mice, we additionally generated Thbs4-deficient Hyp mice, but failed to detect phenotypic differences towards Hyp littermates. With respect to articular cartilage we found that Thbs4-deficient mice display transient thinning of articular cartilage, suggesting a protective role of Thbs4 for joint integrity. Gene expression analysis using porcine primary cells revealed that Thbs4 is not expressed by synovial fibroblasts and that it represents the only member of the Thbs gene family with specific expression in articular, but not in growth plate chondrocytes. In an attempt to identify specific molecular effects of Thbs4 we treated porcine articular chondrocytes with human THBS4 in the absence or presence of conditioned medium from porcine synovial fibroblasts. Here we did not observe a significant influence of THBS4 on proliferation, metabolic activity, apoptosis or gene expression, suggesting that it does not act as a signaling molecule. Taken together, our data demonstrate that Thbs4 is highly expressed in articular chondrocytes, where its presence in the extracellular matrix is required for articular cartilage integrity.     

Fibrinogen,Other Putative Markers of Inflammation,and Weight Gain in Middle‐aged Adults—The ARIC Study

Purpose: Weight gain is an important risk factor for the development of the metabolic syndrome, and inflammatory mediators are strongly associated with this syndrome. Our aim was to investigate whether inflammation predicts the development of weight gain in populations. Research Methods and Procedures: We investigated selected markers of inflammation in the prediction of weight gain over an approximately 3‐year period in a biethnic cohort of 13,017 men and women, 45 to 64 years of age, using multiple linear and logistic regression modeling. Results: In adjusted models, those in the highest quartile of fibrinogen gained, during the first 3 years of follow‐up, an estimated 0.23 kg/year more than those in the lowest quartile (p < 0.001). Adjusted odds of a large (greater than the 90th percentile) weight gain for those in the highest quartile of fibrinogen were 1.65 (95% confidence interval [CI], 1.38 to 1.97) times those in the lowest quartile. Similarly adjusted odds ratios for a large weight gain for those with high levels of white blood cell count, factor VIII, and von Willebrand factor were 1.38 (1.14 to 1.67), 1.28 (1.08 to 1.53), and 1.28 (1.08 to 1.51), respectively. Discussion: Fibrinogen and other putative markers of inflammation predict weight gain in middle‐aged adults. Given the known links between the inflammatory response and intermediary metabolism and the methodological strengths of the Atherosclerosis Risk in Communities (ARIC) cohort, these findings, though without immediate clinical applicability, suggest that inflammatory processes play a role in the development of the metabolic syndrome and cardiovascular disease in part through stimulation of weight gain.     

Ablation of Ghrelin O-Acyltransferase Does Not Improve Glucose Intolerance or Body Adiposity in Mice on a Leptin-Deficient ob/ob Background

Type 2 Diabetes is a global health burden and based on current estimates will become an even larger problem in the future. Developing new strategies to prevent and treat diabetes is a scientific challenge of high priority. The stomach hormone ghrelin has been associated with playing a role in the regulation of glucose homeostasis. However, its precise mechanism and impact on whole glucose metabolism remains to be elucidated. This study aims to clarify the role of the two ghrelin isoforms acyl- and desacyl ghrelin in regulating glucose homeostasis. Therefore ghrelin activating enzyme Ghrelin-O-acyltransferase (GOAT) was ablated in leptin-deficient ob/ob mice to study whether specific acyl ghrelin deficiency or desacyl ghrelin abundance modifies glucose tolerance on a massively obese background. As targeted deletion of acyl ghrelin does not improve glucose homeostasis in our GOAT-ob/ob mouse model we conclude that neither acyl ghrelin nor the increased ratio of desacyl/acyl ghrelin is crucial for controlling glucose homeostasis in the here presented model of massive obesity induced by leptin deficiency.     

L. plantarum,L. salivarius,and L. lactis Attenuate Th2 Responses and Increase Treg Frequencies in Healthy Mice in a Strain Dependent Manner

Many studies on probiotics are aimed at restoring immune homeostasis in patients to prevent disease recurrence or reduce immune-mediated pathology. Of equal interest is the use of probiotics in sub-clinical situations, which are characterized by reduced immune function or low-grade inflammation, with an increased risk of infection or disease as a consequence. Most mechanistic studies focus on the use of probiotics in experimental disease models, which may not be informative for these sub-clinical conditions. To gain better understanding of the effects in the healthy situation, we investigated the immunomodulatory effects of two Lactobacillus probiotic strains, i.e. L. plantarum WCFS1 and L. salivarius UCC118, and a non-probiotic lactococcus strain, i.e. L. lactis MG1363, in healthy mice. We studied the effect of these bacteria on the systemic adaptive immune system after 5 days of administration. Only L. plantarum induced an increase in regulatory CD103⁺ DC and regulatory T cell frequencies in the spleen. However, all three bacterial strains, including L. lactis, reduced specific splenic T helper cell cytokine responses after ex vivo restimulation. The effect on IFN-γ, IL5, IL10, and IL17 production by CD4⁺ and CD8⁺ T cells was dependent on the strain administered. A shared observation was that all three bacterial strains reduced T helper 2 cell frequencies. We demonstrate that systemic immunomodulation is not only observed after treatment with probiotic organisms, but also after treatment with non-probiotic bacteria. Our data demonstrate that in healthy mice, lactobacilli can balance T cell immunity in favor of a more regulatory status, via both regulatory T cell dependent and independent mechanisms in a strain dependent manner.     

The Glucagon-Like Peptide 1 Analogue,Exendin-4, Attenuates the Rewarding Properties of Psychostimulant Drugs in Mice

Glucagon-like peptide 1 (GLP-1) is an incretine hormone that controls consummatory behavior and glucose homeostasis. It is released in response to nutrient ingestion from the intestine and production in the brain has also been identified. Given that GLP-1 receptors are expressed in reward areas, such as the nucleus accumbens and ventral tegmental area, and that common mechanisms regulate food and drug-induced reward we hypothesize that GLP-1 receptors are involved in reward regulation. Herein the effect of the GLP-1 receptor agonist Exendin-4 (Ex4), on amphetamine- and cocaine-induced activation of the mesolimbic dopamine system was investigated in mice. In a series of experiments we show that treatment with Ex4, at a dose with no effect per se, reduce amphetamine- as well as cocaine-induced locomotor stimulation, accumbal dopamine release as well as conditioned place preference in mice. Collectively these data propose a role for GLP-1 receptors in regulating drug reward. Moreover, the GLP-1 signaling system may be involved in the development of drug dependence since the rewarding effects of addictive drugs involves interferences with the mesolimbic dopamine system. Given that GLP-1 analogues, such as exenatide and liraglutide, are clinically available for treatment of type II diabetes, we propose that these should be elucidated as treatments of drug dependence.     

The Endosymbiont Arsenophonus Is Widespread in Soybean Aphid,Aphis glycines,but Does Not Provide Protection from Parasitoids or a Fungal Pathogen

Aphids commonly harbor bacterial facultative symbionts that have a variety of effects upon their aphid hosts, including defense against hymenopteran parasitoids and fungal pathogens. The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is infected with the symbiont Arsenophonus sp., which has an unknown role in its aphid host. Our research goals were to document the infection frequency and diversity of the symbiont in field-collected soybean aphids, and to determine whether Arsenophonus is defending soybean aphid against natural enemies. We performed diagnostic PCR and sequenced four Arsenophonus genes in soybean aphids from their native and introduced range to estimate infection frequency and genetic diversity, and found that Arsenophonus infection is highly prevalent and genetically uniform. To evaluate the defensive role of Arsenophonus, we cured two aphid genotypes of their natural Arsenophonus infection through ampicillin microinjection, resulting in infected and uninfected isolines within the same genetic background. These isolines were subjected to parasitoid assays using a recently introduced biological control agent, Binodoxys communis [Braconidae], a naturally recruited parasitoid, Aphelinus certus [Aphelinidae], and a commercially available biological control agent, Aphidius colemani [Braconidae]. We also assayed the effect of the common aphid fungal pathogen, Pandora neoaphidis (Remaudiere & Hennebert) Humber (Entomophthorales: Entomophthoraceae), on the same aphid isolines. We did not find differences in successful parasitism for any of the parasitoid species, nor did we find differences in P. neoaphidis infection between our treatments. Our conclusion is that Arsenophonus does not defend its soybean aphid host against these major parasitoid and fungal natural enemies.     

Excessive Weight Gain during the First Year of Peritoneal Dialysis Is Associated with Inflammation,Diabetes Mellitus,and a Rapid Decrease in Residual Renal Function

Objectives

Significant weight gain is a potential problem in most patients starting peritoneal dialysis (PD); however, few studies have explored the clinical effects of increased body weight (BW) in these patients. We evaluated the effect of excess weight gain during the first year after PD on residual renal function (RRF).

Methods

A total of 148 incident PD patients were analyzed in a longitudinal observational study. The mean duration of follow-up was 23.8 months. RRF was measured at baseline (within 1 month of starting PD) and thereafter at 6-month intervals for 2–3 years or until loss of RRF. BW was measured at the time of RRF measurement, and excess weight gain was defined as a BW increase over the median value (3.0%).

Results

The median 1-year increase in BW was 2.3kg (IQR, 1.01–4.58) or 3.0% (IQR, 1.13–5.31). The mean slope of RRF decline was –0.068 ± 0.053 mL/min/month/1.73m², and RRF loss developed in 48 patients at a mean follow-up time of 19.4 ± 6.8 months. Patients with BW increases > 3.0% showed significantly increased RRF decline rate compared to those without excess weight gain (p<0.001), and the BW increase (%/year) correlated significantly with higher hs-CRP levels and RRF decline rate. High systolic blood pressure, diabetes, large amount of proteinuria and excess BW gain significantly influenced the RRF decline rate. Also, it increased the risk of RRF loss by 4.17-fold (95% confidence intervals, 1.87–9.28; p<0.001).

Conclusions

Excess weight gain during the first year of PD was closely linked to systemic inflammation, diabetes and rapid decline in RRF.     

The Lung Inflammation and Skeletal Muscle Wasting Induced by Subchronic Cigarette Smoke Exposure Are Not Altered by a High-Fat Diet in Mice

Obesity and cigarette smoking independently constitute major preventable causes of morbidity and mortality and obesity is known to worsen lung inflammation in asthma. Paradoxically, higher body mass index (BMI) is associated with reduced mortality in smoking induced COPD whereas low BMI increases mortality risk. To date, no study has investigated the effect of a dietary-induced obesity and cigarette smoke exposure on the lung inflammation and loss of skeletal muscle mass in mice. Male BALB/c mice were exposed to 4 cigarettes/day, 6 days/week for 7 weeks, or sham handled. Mice consumed either standard laboratory chow (3.5 kcal/g, 12% fat) or a high fat diet (HFD, 4.3 kcal/g, 32% fat). Mice exposed to cigarette smoke for 7 weeks had significantly more inflammatory cells in the BALF (P<0.05) and the mRNA expression of pro-inflammatory cytokines and chemokines was significantly increased (P<0.05); HFD had no effect on these parameters. Sham- and smoke-exposed mice consuming the HFD were significantly heavier than chow fed animals (12 and 13%, respectively; P<0.05). Conversely, chow and HFD fed mice exposed to cigarette smoke weighed 16 and 15% less, respectively, compared to sham animals (P<0.05). The skeletal muscles (soleus, tibialis anterior and gastrocnemius) of cigarette smoke-exposed mice weighed significantly less than sham-exposed mice (P<0.05) and the HFD had no protective effect. For the first time we report that cigarette smoke exposure significantly decreased insulin-like growth factor-1 (IGF-1) mRNA expression in the gastrocnemius and tibialis anterior and IGF-1 protein in the gastrocnemius (P<0.05). We have also shown that cigarette smoke exposure reduced circulating IGF-1 levels. IL-6 mRNA expression was significantly elevated in all three skeletal muscles of chow fed smoke-exposed mice (P<0.05). In conclusion, these findings suggest that a down-regulation in local IGF-1 may be responsible for the loss of skeletal muscle mass following cigarette smoke exposure in mice.     

4-Aminopyridine Does Not Enhance Flocculus Function in Tottering,a Mouse Model of Vestibulocerebellar Dysfunction and Ataxia

The potassium channel antagonist 4-aminopyridine (4-AP) improves a variety of motor abnormalities associated with disorders of the cerebellum. The most rigorous quantitative data relate to 4-AP''s ability to improve eye movement deficits in humans referable to dysfunction of the cerebellar flocculus. Largely based on work in the ataxic mouse mutant tottering (which carries a mutation of the Cacna1a gene of the P/Q voltage-activated calcium channel), 4-AP is hypothesized to function by enhancing excitability or rhythmicity of floccular Purkinje cells. We tested this hypothesis by determining whether systemic or intrafloccular administration of 4-AP would ameliorate the eye movement deficits in tottering that are attributable to flocculus dysfunction, including the reductions in amplitude of the yaw-axis vestibulo-ocular reflex (VOR) and vision-enhanced vestibulo-ocular reflex (VVOR), and the optokinetic reflex (OKR) about yaw and roll axes. Because tottering''s deficits increase with age, both young and elderly mutants were tested to detect any age-dependent 4-AP effects. 4-AP failed to improve VOR, VVOR, and OKR gains during sinusoidal stimuli, although it may have reduced the tendency of the mutants'' responses to VOR and VVOR to decline over the course of a one-hour recording session. For constant-velocity optokinetic stimuli, 4-AP generated some enhancement of yaw OKR and upward-directed roll OKR, but the effects were also seen in normal C57BL/6 controls, and thus do not represent a specific reversal of the electrophysiological consequences of the tottering mutation. Data support a possible extra-floccular locus for the effects of 4-AP on habituation and roll OKR. Unilateral intrafloccular 4-AP injections did not affect ocular motility, except to generate mild eye elevations, consistent with reduced floccular output. Because 4-AP did not produce the effects expected if it normalized outputs of floccular Purkinje cells, there is a need for further studies to elucidate the drug''s mechanism of action on cerebellar motor dysfunction.     

The Intra- or Extracellular Redox State Was Not Affected by a High vs. Low Glycemic Response Diet in Mice

A low glycemic response (LGR) vs. high glycemic response (HGR) diet helps curtail the development of obesity and diabetes, though the mechanisms are unknown. We hypothesized that consumption of a HGR vs. a LGR diet would lead to a more oxidized circulating redox state and predicted that a HGR diet would increase fat accumulation, reduce insulin sensitivity, and impair metabolic acclimation to a high fat diet in a mouse model. Hence, male C57BL/6 mice consumed a HGR or LGR diet for 16 weeks and a subset of the mice subsequently consumed a high fat diet for 4 weeks. We found that body mass increased at a faster rate for those consuming the HGR diet. Percent body fat was greater and percent lean mass was lesser in the HGR group starting at 12 weeks. However, the groups did not differ in terms of glucose tolerance at week 14 and metabolic parameters (respiratory exchange ratio, heat production, activity) at weeks 4 or 15. Moreover, mice on either diet did not show differences in metabolic acclimation to the high fat leg of the study. At the termination of the study, the groups did not differ in terms of redox pairs (lactate/pyruvate and β-hydroxybutyrate/acetoacetate) or thioredoxin reductase activity in blood. Also, total and oxidized glutathione levels and lipid peroxidation were similar in blood and liver. Correlations between baseline measures, longitudinal parameters, environmental conditions, and terminal metrics revealed that individual mice have innate propensities to metabolic regulation that may be difficult to perturb with diet alone; for example, starting mass correlated negatively with energy expenditure 4 weeks into the study and total hepatic glutathione at the end of the study. In conclusion, these data suggest that the mechanism by which HGR carbohydrates contributes to obesity is not via prolonged oxidation of the circulating redox state.     

Prophylactic Application of MA-[d-Leu-4]-OB3, a Small Molecule Synthetic Peptide Leptin Mimetic,Prevents or Slows the Progression of Obesity,Insulin Resistance,and Cognitive Impairment in a Mouse Model of Type 2 Diabetes Mellitus

International Journal of Peptide Research and Therapeutics - Oral delivery of MA-[d-Leu-4]-OB3 has been shown to significantly improve energy balance, glycemic control, dyslipidemia, and episodic...     

The Axl-Regulating Tumor Suppressor miR-34a Is Increased in ccRCC but Does Not Correlate with Axl mRNA or Axl Protein Levels

Background

High expression of the receptor tyrosine kinase Axl is associated with poor prognosis in patients with Renal Cell Carcinoma (RCC), the most common malignancy of the kidney. The miR-34a has been shown to directly regulate Axl in cancer cells. The miR-34a is a mediator of p53-dependent tumor suppression, and low expression of miR-34a has been associated with worse prognosis in several cancers. Our aim was to elucidate whether miR-34a or the other members of the miR-34 family (miR-34b/c) regulate Axl in RCC.

Methodology and Results

Using western blot, flow cytometry, and RT-qPCR, we showed that Axl mRNA and protein are downregulated in 786-O cells by miR-34a and miR-34c but not by miR-34b. A luciferase reporter assay demonstrated direct interaction between the Axl 3’ UTR and miR-34a and miR-34c. The levels of miR-34a/b/c were measured in tumor tissue in a cohort of 198 RCC patients, and the levels of miR-34a were found to be upregulated in clear cell RCC (ccRCC) tumors, but not associated with patient outcome. Neither of the miR-34 family members correlated with Axl mRNA, soluble Axl protein in serum, nor with immunohistochemistry of Axl in tumor tissue. In addition, we measured mRNA levels of a known miR-34a target, HNF4A, and found the HNF4A levels to be decreased in ccRCC tumors, but unexpectedly correlated positively rather than negatively with miR-34a.

Conclusions

Although miR-34a and miR-34c can regulate Axl expression in vitro, our data indicates that the miR-34 family members are not the primary regulators of Axl expression in RCC.     

MA-[D-Leu-4)-OB3, a Small Molecule Synthetic Peptide Leptin Mimetic,Improves Serum Lipid Profiles in Mouse Models of Type 1 and Type 2 Diabetes Mellitus

International Journal of Peptide Research and Therapeutics - Diabetic dyslipidemia, a common pattern of lipid abnormalities associated with diabetes, is characterized by hyperglycemia, elevated...