Direct Causal Role Research Articles

PO-328 No such thing as a perfect copy – DNA replication profoundly influences how most environmental carcinogens and epigenetic marks induce mutations

IntroductionUnderstanding the mechanisms of mutagenesis in cancer is important for the prevention and treatment of the disease. While it is well known that environmental carcinogens such as tobacco smoke substantially increase disease incidence, other studies have suggested that the number of replicative cycles a cell undergoes is the biggest risk factor for cancer. To reconcile these divergent observations, it is critical to understand of and how DNA replication influences distinct mechanisms of mutagenesis.Material and methodsHere, we developed a methodology to identify replication-strand and timing asymmetry of mutational signatures, representing different mutagenic mechanisms.Results and discussionsApplying this computational framework to whole-genome sequencing data from over 3000 patients, spanning 19 cancer types, reveals a significant impact of DNA replication in 22 out of 29 mutational signatures. This includes some well-known examples, such as the APOBEC class of enzymes that preferentially attack cytosine residues on the lagging strand. Notably, however, we find that most exogenous mutagens, such as UV light or tobacco smoke, also exhibit significant replication strand and timing asymmetry. Even more surprisingly, mutations of epigenetically methylated cytosine residues show clear replication strand asymmetry in cancers deficient of different error correction mechanisms. Finally, our results shed light on the potential mechanisms underlying several unknown mutagenic signatures, such as Signature 17 which is associated with gastric and oesophageal cancers. We show that this process is likely to involve reactive oxygen species altering the composition of the dNTP pool, leading to replication-associated mutations.ConclusionOur findings demonstrate that DNA replication and the associated repair have a bigger influence on the fixation of DNA damage into somatic mutations than previously acknowledged. In some cases, such as for Signature 17 or methylated cytosine, our results point towards a direct causal role of the replicative machinery in the formation of mutations. In summary, our discoveries shed new light onto the link between tissue regeneration, mutagenesis and cancer.

Mitochondrial DNA DAMPs Induce Inflammation and Insulin Resistance

Increasing evidence showed that mitochondrial DNA (mtDNA), as a part of mitochondrial damage-associated molecular patterns (DAMPs), induces an immune response and inflammation in immune, as well as in cells of nonnimmune origin. As insulin resistance and type 2 diabetes are characterized by a persistent chronic inflammation, the aim if this study was to evaluate if mtDNA DAMPs induce an inflammatory responses in skeletal muscle cells and induce insulin resistance both in vitro and vivo. In vitro study showed that exogenous mtDNA fragments induced TLR9-mediated NF-κB activation in primary muscle cells. Also, we found that mtDNA DAMPs and palmitate increased TLR9 content in muscle cells. Furthermore, mtDNA DAMPs reduced insulin signaling and insulin stimulated glucose uptake in primary muscle cells. Importantly, administration of exogenous mtDNA DAMPs induced inflammatory signaling, hyperglycemia and insulin resistance in vivo, providing a direct causative role for mtDNA DAMPs in the development of insulin resistance. Parallel studies in vivo showed that high fat diet-induced insulin resistant mice (Yuzefovych et al, 2013, PLOS One) have elevated circulating mtDNA DAMPs contents which were associated with increased mtDNA damage in skeletal muscle and liver, increased oxidative stress and content of TLR9 in skeletal muscle. Collectively, this study identifies a novel role for mtDNA as a pro-inflammatory molecule which promotes insulin resistance. Ultimately, this can provide new clinical implications both to design novel therapeutic strategies and cost-effective biomarkers of insulin resistance progression. Disclosure L. Yuzefovych: None. V.M. Pastukh: None. L. Rachek: None.

Iatrogenic Takotsubo Cardiomyopathy Secondary to Norepinephrine by Continuous Infusion for Shock.

Takotsubo cardiomyopathy is a condition characterized by transient left ventricular systolic and diastolic dysfunction, with a possible direct causal role of catecholamine in its pathophysiology. We present a case of a woman with shock and adrenal insufficiency in whom Takotsubo cardiomyopathy developed after treatment with norepinephrine. This case confirms the direct causal role of catecholamine in the pathophysiology of Takotsubo cardiomyopathy. An 82-year-old woman presented with asthenia, anorexia, nausea and abdominal pain. The patient had been on chronic corticosteroid therapy until 3 months before, when she underwent abdominal surgery and corticosteroids were stopped. She now presented with acute kidney injury, hyponatremia and hyperkalemia and shock. A norepinephrine continuous infusion was administered to maintain a mean arterial pressure over 65 mmHg. An echocardiogram showed severe hypokinesis in the apical segments and hyperdynamic basal segments, with an ejection fraction of 25%. Plasma cortisol level was 4.5 μg/dL (reference range 5–25). Corticosteroid therapy was begun and norepinephrine was tapered and stopped. A new echocardiogram showed normalization of cardiac wall motion and an ejection fraction of 70%. This case highlights the importance of the correction of the cause of shock, as well as the risks associated with the use of norepinephrine if hypotension is severe or if it persists despite fluid administration, as usually recommended. It also confirms the direct causal role of catecholamine in the pathophysiology of Takotsubo cardiomyopathy. To the best of our knowledge, this is the first report of stress-induced cardiomyopathy secondary to norepinephrine by continuous infusion for shock.LEARNING POINTSTakotsubo cardiomyopathy is a condition characterized by transient left ventricular dysfunction of the apex and midventricle in the absence of attributable coronary artery disease.In patients with shock and adrenal insufficiency, who can be erroneously interpreted as septic shock, Takotsubo cardiomyopathy can develop after treatment with norepinephrine.In the management of shock, there are risks associated with recommending the use of norepinephrine if hypotension is severe or if it persists despite fluid administration, when the cause of shock is other than septic shock and is not corrected.There is a direct causal role of catecholamine in the pathophysiology of Takotsubo cardiomyopathy.

OP.5C.05] SERUM URIC ACID IS INCREASED IN NORMOTENSIVE OBESE CHILDREN WITH A PARENTAL HYSTORY OF HYPERTENSION

Objective: Increased uric acid levels are closely associated with new-onset hypertension in children, and pilot studies showed that pharmacological lowering of uric acid may reduce blood pressure (BP) in obese pediatric patients. Nevertheless, controversy remains concerning a direct causative role of serum uric acid (SUA) in the pathogenesis of essential hypertension (EH). Our study was aimed to determine if normotensive obese children and adolescent offspring of adults with EH show SUA levels different than those of pediatric subjects in whom there is non family history of EH. Design and method: Fifty-nine obese normotensive children and adolescents, attending for metabolic assessment the Pediatric Diabetes Unit, Children's Hospital “G. Di Cristina”, and for cardiovascular evaluation the ESH Hypertension excellence center of the University of Palermo, were studied. All the subjects, aged between 8 and 17 years, underwent routine blood chemistry and oral glucose tolerance test with glucose and insulin determinations. All subjects had blood pressure determinations below the 90th percentile and had no previous history of elevated blood pressure. Results: There were 14 subjects whose parents were both normotensive (FH—), and the remaining 45 subjects whose one or both parents were hypertensive. FH + did not differ regarding age, sex distribution, blood pressure values, body mass index, waist circumference, serum glucose levels when compared to FH-. Among the metabolic parameters assessed, only SUA was significantly higher in FH+ than in FH - (p = 0.007; figure 1).This difference held after adjusting for age, gender and BMI (p = 0.01). Conclusions: Our results, showing higher values of SUA in normotensive obese children and adolescents with parental history of EH, seem to support the hypothesis that increased uric acid may precede and determine the development of hypertension.

HDL and atherosclerotic cardiovascular disease: genetic insights into complex biology

Plasma levels of HDL cholesterol (HDL-C) predict the risk of cardiovascular disease at the epidemiological level, but a direct causal role for HDL in cardiovascular disease remains controversial. Studies in animal models and humans with rare monogenic disorders link only particular HDL-associated mechanisms with causality, including those mechanisms related to particle functionality rather than cholesterol content. Mendelian randomization studies indicate that most genetic variants that affect a range of pathways that increase plasma HDL-C levels are not usually associated with reduced risk of cardiovascular disease, with some exceptions, such as cholesteryl ester transfer protein variants. Furthermore, only a fraction of HDL-C variation has been explained by known loci from genome-wide association studies (GWAS), suggesting the existence of additional pathways and targets. Systems genetics can enhance our understanding of the spectrum of HDL pathways, particularly those pathways that involve new and non-obvious GWAS loci. Bioinformatic approaches can also define new molecular interactions inferred from both large-scale genotypic data and RNA sequencing data to reveal biologically meaningful gene modules and networks governing HDL metabolism with direct relevance to disease end points. Targeting these newly recognized causal networks might inform the development of novel therapeutic strategies to reduce the risk of cardiovascular disease.

Role of the fatty acid-binding protein 4 in heart failure and cardiovascular disease

Obesity and ectopic fat accumulation in non-adipose tissues are major contributors to heart failure (HF) and cardiovascular disease (CVD). Adipocytes act as endocrine organs by releasing a large number of bioactive molecules into the bloodstream, which participate in a communication network between white adipose tissue and other organs, including the heart. Among these molecules, fatty acid-binding protein 4 (FABP4) has recently been shown to increase cardiometabolic risk. Both clinical and experimental evidence have identified FABP4 as a relevant player in atherosclerosis and coronary artery disease, and it has been directly related to cardiac alterations such as left ventricular hypertrophy (LVH) and both systolic and diastolic cardiac dysfunction. The available interventional studies preclude the establishment of a direct causal role of this molecule in CVD and HF and propose FABP4 as a biomarker rather than as an aetiological factor. However, several experimental reports have suggested that FABP4 may act as a direct contributor to cardiac metabolism and physiopathology, and the pharmacological targeting of FABP4 may restore some of the metabolic alterations that are conducive to CVD and HF. Here, we review the current knowledge regarding FABP4 in the context of HF and CVD as well as the molecular basis by which this protein participates in the regulation of cardiac function.

Lipid metabolism and its implications for type 1 diabetes-associated cardiomyopathy.

Diabetic cardiomyopathy was first defined over four decades ago. It was observed in small post-mortem studies of diabetic patients who suffered from concomitant heart failure despite the absence of hypertension, coronary disease or other likely causal factors, as well as in large population studies such as the Framingham Heart Study. Subsequent studies continue to demonstrate an increased incidence of heart failure in the setting of diabetes independent of established risk factors, suggesting direct effects of diabetes on the myocardium. Impairments in glucose metabolism and handling receive the majority of the blame. The role of concomitant impairments in lipid handling, particularly at the level of the myocardium, has however received much less attention. Cardiac lipid accumulation commonly occurs in the setting of type 2 diabetes and has been suggested to play a direct causal role in the development of cardiomyopathy and heart failure in a process termed as cardiac lipotoxicity. Excess lipids promote numerous pathological processes linked to the development of cardiomyopathy, including mitochondrial dysfunction and inflammation. Although somewhat underappreciated, cardiac lipotoxicity also occurs in the setting of type 1 diabetes. This phenomenon is, however, largely understudied in comparison to hyperglycaemia, which has been widely studied in this context. The current review addresses the changes in lipid metabolism occurring in the type 1 diabetic heart and how they are implicated in disease progression. Furthermore, the pathological pathways linked to cardiac lipotoxicity are discussed. Finally, we consider novel approaches for modulating lipid metabolism as a cardioprotective mechanism against cardiomyopathy and heart failure.

Alcohol and Cardiovascular Disease: How Much is Too Much?

Previous research suggests that low-moderate alcohol consumption may have cardioprotective effects, while heavy or binge-pattern drinking is harmful. New evidence and research methodology may inform safe thresholds of alcohol use. This review examines recent evidence regarding alcohol's effect on cardiovascular disease, with a special consideration of pattern, drink type, and total quantity. New epidemiologic research confirms the potential harmful cardiovascular effects of heavy episodic alcohol use and does not support the previous observation that low-moderate alcohol use protects against stroke. Alcohol consumption also appears to have a continuous positive relationship with the risk of atrial fibrillation. In addition, Mendelian randomization analyses suggest that alcohol may have a direct causal role in adverse cardiovascular effects. Recent studies have confirmed that heavy alcohol use (>14 drinks per week in women and >21 drinks per week in men) and heavy episodic drinking are associated with an increased risk of mortality. New research raises concerns that even low-moderate alcohol use may not offer cardio- or cerebrovascular protection. Drinking ≥3 drinks per day on a regular basis or ≥5 drinks in any one episode should be discouraged.

Disentangling life: Darwin, selectionism, and the postgenomic return of the environment

In this paper, I analyze the disruptive impact of Darwinian selectionism for the century-long tradition in which the environment had a direct causative role in shaping an organism's traits. In the case of humans, the surrounding environment often determined not only the physical, but also the mental and moral features of individuals and whole populations. With its apparatus of indirect effects, random variations, and a much less harmonious view of nature and adaptation, Darwinian selectionism severed the deep imbrication of organism and milieu posited by these traditional environmentalist models. This move had radical implications well beyond strictly biological debates. In my essay, I discuss the problematization of the moral idiom of environmentalism by William James and August Weismann who adopted a selectionist view of the development of mental faculties. These debates show the complex moral discourse associated with the environmentalist-selectionist dilemma. They also well illustrate how the moral reverberations of selectionism went well beyond the stereotyped associations with biological fatalism or passivity of the organism. Rereading them today may be helpful as a genealogical guide to the complex ethical quandaries unfolding in the current postgenomic scenario in which a revival of new environmentalist themes is taking place.

Redox Signaling and Persistent Pulmonary Hypertension of the Newborn.

Reactive oxygen species (ROS) are redox-signaling molecules that are critically involved in regulating endothelial cell functions, host defense, aging, and cellular adaptation. Mitochondria are the major sources of ROS and important sources of redox signaling in pulmonary circulation. It is becoming increasingly evident that increased mitochondrial oxidative stress and aberrant signaling through redox-sensitive pathways play a direct causative role in the pathogenesis of many cardiopulmonary disorders including persistent pulmonary hypertension of the newborn (PPHN). This chapter highlights redox signaling in endothelial cells, antioxidant defense mechanism, cell responses to oxidative stress, and their contributions to disease pathogenesis.

Anti-citrullinated protein antibodies and high levels of rheumatoid factor are associated with systemic bone loss in patients with early untreated rheumatoid arthritis.

BackgroundAutoantibodies such as anti-citrullinated protein antibodies (ACPA) are major risk factors for articular bone destruction from the earliest phases of rheumatoid arthritis (RA). The aim of the current study was to determine whether RA-associated autoantibodies also impact on systemic bone loss in patients with early disease.MethodsSystemic bone mineral density (BMD) was measured in the lumbar spine and the hip in 155 consecutive treatment-naïve patients with early RA (median symptom duration 13 weeks). Demographic and disease-specific parameters, including clinical disease activity, ultrasonographic (US) examination of the hands and wrists, radiographic scoring of joint damage, ACPA and rheumatoid factor (RF) levels were recorded from all patients. Reduced BMD was defined as Z score ≤ -1 SD and analysed in relation to disease-related characteristics and autoantibody subgroups.ResultsReduced BMD was found in 25.5 % of the patients in the spine and 19.4 % in the hip. Symptom duration, clinical and US disease activity, functional disability and radiographic damage did not significantly impact on spine and hip BMD loss in regression analyses adjusted for possible confounders (age, gender, menopausal status, current smoking, body mass index). In contrast, ACPA positivity (at any level) negatively affected the spine Z-score (adjusted OR (95 % CI) 2.76 (1.19 to 6.42)); the hip Z score was affected by high titres only (adjusted OR (95 % CI) 2.96 (1.15 to 7.66)). The association of ACPA with reduced BMD in the spine was confirmed even at low levels of RF (adjusted OR (95 % CI) 2.65 (1.01 to 7.24)), but was further increased by concomitant high RF (adjusted OR (95 % CI) 3.38 (1.11 to 10.34)). In contrast, Z scores in the hip were significantly reduced only in association with high ACPA and RF (adjusted OR (95 % CI) 4.96 (1.48 to 16.64)).ConclusionsSystemic BMD in patients with early RA is reduced in relation with ACPA positivity and high RF levels. This finding supports the notion that RA-associated autoimmunity may have a direct causative role in bone remodeling.

Triglyceride-rich lipoproteins as a causal factor for cardiovascular disease.

Approximately 25% of US adults are estimated to have hypertriglyceridemia (triglyceride [TG] level ≥150 mg/dL [≥1.7 mmol/L]). Elevated TG levels are associated with increased cardiovascular disease (CVD) risk, and severe hypertriglyceridemia (TG levels ≥500 mg/dL [≥5.6 mmol/L]) is a well-established risk factor for acute pancreatitis. Plasma TG levels correspond to the sum of the TG content in TG-rich lipoproteins (TRLs; ie, very low-density lipoproteins plus chylomicrons) and their remnants. There remains some uncertainty regarding the direct causal role of TRLs in the progression of atherosclerosis and CVD, with cardiovascular outcome studies of TG-lowering agents, to date, having produced inconsistent results. Although low-density lipoprotein cholesterol (LDL-C) remains the primary treatment target to reduce CVD risk, a number of large-scale epidemiological studies have shown that elevated TG levels are independently associated with increased incidence of cardiovascular events, even in patients treated effectively with statins. Genetic studies have further clarified the causal association between TRLs and CVD. Variants in several key genes involved in TRL metabolism are strongly associated with CVD risk, with the strength of a variant’s effect on TG levels correlating with the magnitude of the variant’s effect on CVD. TRLs are thought to contribute to the progression of atherosclerosis and CVD via a number of direct and indirect mechanisms. They directly contribute to intimal cholesterol deposition and are also involved in the activation and enhancement of several proinflammatory, proapoptotic, and procoagulant pathways. Evidence suggests that non-high-density lipoprotein cholesterol, the sum of the total cholesterol carried by atherogenic lipoproteins (including LDL, TRL, and TRL remnants), provides a better indication of CVD risk than LDL-C, particularly in patients with hypertriglyceridemia. This article aims to provide an overview of the available epidemiological, clinical, and genetic evidence relating to the atherogenicity of TRLs and their role in the progression of CVD.

Editorial: Limbic Encephalitis: Autoimmune Impact on Inhibitory GABAergic Neuronal Pathways in Temporal Lobe Epilepsy.

The Editorial on the Research Topic Limbic Encephalitis: Autoimmune Impact on Inhibitory GABAergic Neuronal Pathways in Temporal Lobe Epilepsy Mesial temporal lobe epilepsy (mTLE), a common adult epilepsy syndrome, is generally acquired. Recent data have demonstrated autoimmune inflammation predominantly affecting the limbic structures of the brain as a cause of adult mTLE development (1–3). Patients usually present with mesial temporal lobe seizures with interictal temporal epileptiform activity and slowing, episodic memory disturbance, and a variety of other behavioral, emotional, and cognitive changes. Magnetic resonance imaging typically exhibits volume and signal changes of the amygdala and hippocampus, and specific anti-neuronal antibodies binding to either intracellular or plasma membrane neuronal antigens can be detected in sera and cerebrospinal fluid. Glutamic acid decarboxylase (GAD) (4) and γ-aminobutyric acid (GABA)-B receptors (5) have recently been identified as distinct neuronal antigens in limbic encephalitis. This suggests a possible involvement of disturbed inhibitory GABAergic signaling in the etiology of seizures and neuropsychiatric symptoms characterizing this form of autoimmune epilepsy. Due to restricted access to their target antigen, autoantibodies directed toward intracellular GAD are believed to bear limited pathogenic potential, and neurons may be affected by autoreactive T cells instead (1). In contrast, autoantibodies against plasma membrane GABA-B receptors have been suggested to exert direct pathogenic effects (6), and the role of autoreactive T cells in these disorders is unclear at present (1). In the Frontiers in Neurology Research Topic “Limbic Encephalitis: Autoimmune Impact on Inhibitory GABAergic Neuronal Pathways in Temporal Lobe Epilepsy,” authors provide a survey on clinical and scientific aspects of autoimmune inflammation in mTLE. Ehling et al. review and discuss the role of CD8+ T cells–neuron interactions, whereas Seebohm et al. summarize the current knowledge and discuss technical approaches to study the autoantibody–receptor interactions in limbic encephalitis. Haselmann et al. present a methodical approach to investigate the impact of stereotactically injected human IgG fractions on GABAergic signaling in intact murine hippocampal network ex vivo. Stemmler et al. could not detect any effect of serum of a patient with confirmed GAD antibody-associated limbic encephalitis on GABAergic neurotransmission in murine cultured hippocampal networks, challenging the view that the presence of such autoantibodies compromise inhibitory network function. Widman et al. report a correlation of the CD8+ T cells in the cerebrospinal fluid with clinical and paraclinical measures of disease activity together with an unambiguous response to treatment with basiliximab, a chimeric mouse–human monoclonal antibody to the α-chain of the interleukin-2 receptor (CD25) on T cells in a patient with GAD antibody-associated limbic encephalitis. This strongly argues in favor of a pathogenic role of CD8+ T cells in this form of autoimmune temporal lobe epilepsy. The amygdala is central for the generation of adequate homoeostatic behavioral responses to emotionally significant external stimuli following processing in a variety of parallel neuronal circuits. Melzer et al. hypothesize that adaptive cellular and humoral autoimmunity may target and modulate distinct inhibitory or excitatory neuronal networks within the amygdala and thereby strongly impact processing of emotional stimuli and corresponding behavioral responses in patients with limbic encephalitis. Indeed, Schroder et al. show defective modulation of sympathetic ­autonomic responses during emotional stimulation in limbic encephalitis probably due to impaired functioning of the amygdala. Witt et al. present a case of GAD antibody-associated limbic encephalitis with predominant involvement of the left amygdala that presented with retrograde episodic memory impairment, characterized by loss of emotional attachment and autonoetic awareness of usually highly emotional autobiographical memories consistent with the known role of the amygdala as part of the basolateral limbic circuit relevant for emotional valence of memories. Furthermore, a special form of anterograde episodic memory impairment was present called accelerated long-term forgetting, consisting of accelerated loss or impaired access to newly encoded episodes. These cognitive and emotional disturbances occurred in the absence of overt epileptic seizures, suggesting a direct causal role of autoimmune inflammation within temporomesial structures.

The Editor's Round Table: Current Perspectives on Triglycerides and Atherosclerosis

Despite several decades of research about triglycerides and atherosclerotic cardiovascular disease, controversy still surrounds the question whether triglycerides are more than a biomarker and play a direct causative role in atherogenesis. In this Editor’s Roundtable, a panel of leading lipid experts was invited to address this question and several closely related issues about triglycerides, including:

K-Ras protein as a drug target.

K-Ras proteins are major drivers of human cancers, playing a direct causal role in about one million cancer cases/year. In cancers driven by mutant K-Ras, the protein is locked in the active, GTP-bound state constitutively, through a defect in the off-switch mechanism. As such, the mutant protein resembles the normal K-Ras protein from a structural perspective, making therapeutic attack extremely challenging. K-Ras is a member of a large family of related proteins, which share very similar GDP/GTP-binding domains, making specific therapies more difficult. Furthermore, Ras proteins lack pockets to which small molecules can bind with high affinity, with a few interesting exceptions. However, new insights into the structure and function of K-Ras proteins reveal opportunities for intervention that were not appreciated many years ago, when efforts were launched to develop K-Ras therapies. Furthermore, K-Ras undergoes post-translational modification and interactions with cellular signaling proteins that present additional therapeutic opportunities, such as specific binding to calmodulin and regulation of non-canonical Wnt signaling.

Birth Weight, Gestational Age, Fetal Growth and Childhood Asthma Hospitalization.

Background: Childhood asthma may have a fetal origin through fetal growth and development of the immunocompetence or respiratory organs. Objective: We examined to which extent short gestational age, low birth weight and fetal growth restriction were associated with an increased risk of asthma hospitalization in childhood. Methods: We undertook a cohort study based on several national registers in Denmark, Sweden and Finland. We included all live singleton born children in Denmark during 1979-2005 (N = 1,538,093), in Sweden during 1973-2004 (N = 3,067,670), and a 90% random sample of singleton children born in Finland during 1987-2004 (N = 1,050,744). The children were followed from three years of age to first hospitalization for asthma, emigration, death, their 18th birthday, or the end of study (the end of 2008 in Denmark, and the end of 2007 in Sweden or Finland), whichever came first. We computed the pseudo-values for each observation and used them in a generalized estimating equation to estimate relative risks (RR) for asthma hospitalization. Results: A total of 131,783 children were hospitalized for asthma during follow-up. The risk for asthma hospitalization consistently increased with lower birth weight and shorter gestational age. A 1000-g decrease in birth weight corresponded to a RR of 1.17 (95% confidence interval (CI) 1.15-1.18). A one-week decrease in gestational age corresponded to a RR of 1.05 (95% CI 1.04-1.06). Small for gestational age was associated with an increased risk of asthma hospitalization in term but not in preterm born children. Conclusions: Fetal growth and gestational age may play a direct or indirect causal role in the development of childhood asthma.

MicroRNA circulating in the early aftermath of motor vehicle collision predict persistent pain development and suggest a role for microRNA in sex-specific pain differences.

BackgroundMolecular mediators influencing the transition from acute to persistent musculoskeletal pain following common stress exposures such as motor vehicle collision (MVC) remain poorly understood. In this exploratory, proof of concept study, we compared circulating microRNA (miRNA) expression profiles in the early aftermath of MVC among individuals who did and did not subsequently develop persistent pain. Blood RNA samples were obtained from African American individuals (n = 53) who presented to the emergency department after MVC and were discharged to home after evaluation. The presence or absence of severe pain in the axial region, the most common and morbid region in which post-MVC pain occurs, was assessed 6 weeks following MVC via standardized questionnaire. miRNA expression was determined using miRNA-sequencing; nonparametric analyses were used to compare miRNA expression levels among individuals with and without persistent pain.ResultsThirty-two mature miRNA were differentially expressed (p < 0.05) in those with and without severe axial pain at 6 weeks. miR-135a-5p, a regulator of the serotonin receptor that is known to be stress-responsive, differed most significantly between groups (p = 3 × 10−4). This miRNA, and miR-3613-3p (p = 0.001) survived correction for multiple testing (FDR = 0.15) in this small sample. Interestingly, differentially expressed miRNA were enriched for X chromosome location. In secondary analyses, the eight X chromosome miRNA were (a) more significantly associated with axial pain in women than men, (b) expressed more highly in the peripheral blood of women than men, and (c) predicted in pathway analyses (DIANA miRPath v 2.0) to regulate neuronal and neuroendocrine pathways previously implicated in various pain pathologies.ConclusionsThese results show that circulating miRNA predict persistent severe axial pain after MVC and suggest that they may be involved in the pathogenesis of post-traumatic musculoskeletal pain. However, further studies are needed to determine if these miRNA play a direct causal role.Electronic supplementary materialThe online version of this article (doi:10.1186/s12990-015-0069-3) contains supplementary material, which is available to authorized users.

Abstract 5083: Adipocytes promote pancreatic cancer cell proliferation and progression

Abstract Pancreatic cancer (PC) is a devastating disease with an extremely low survival rate. By the year 2030, this disease is projected to be the second deadliest cancer, bypassing breast, prostate and colorectal cancer-related fatalities. While population-based epidemiological studies have reported that obesity and a higher BMI (body mass index) not only increase the risk of developing PC but also promote tumor aggressiveness, and reduce overall patient survival, how obesity may influence pancreatic tumor progression and aggressiveness is not well understood. We hypothesize that the increased local presence of mature adipocytes (in obesity) within the pancreatic microenvironment markedly enhances the tumorigenic functions of pancreatic tumors and tumor-associated stroma, thereby accelerating tumor growth and progression. In this study, we used mature adipocytes and pancreatic cancer (PC) and pancreatic stellate (PSC) cell lines and a variety of in vitro functional assays including migration, proliferation, gemcitabine chemoresistance and development of a fibrotic phenotype, to determine whether local interactions between adipocytes and tumor cells promote PC growth and to identify the underlying mechanism/s. In cell migration assays, both PCs (MiaPaca-2, AsPC-1 and BxPC-3) and PSCs (HImPSC) migrated at significantly higher rates towards adipocyte conditioned medium (ACM) compared to serum-free or normal human fibroblast conditioned medium. The ACM-mediated stimulation of migration was dose-dependent and adipocyte-specific. ACM pretreatment of PC cells as well as PSCs resulted in a significant increase in proliferation rates. Given that the development of chemoresistance is a critical challenge in PC therapy, we next investigated the effects of adipocytes on PC cell gemcitabine toxicity. Pretreatment with ACM resulted in 50-70% increased cell viability for PC and PSC's in the presence of gemcitabine. Extensive fibrosis is a hallmark of pancreatic tumors and both PC and PSCs contribute to excessive ECM production in the PC microenvironment. Compared to cells treated with full medium, ACM-treated PSC and PC cells significantly upregulated their expression of fibronectin and Collagen VI. Taken together, our results indicate that secreted factor/s present in ACM promote cell migration, proliferation, gemcitabine resistance and induce a fibrotic phenotype in PC and PSC. Current efforts in our laboratory are focused on identifying the adipocyte-secreted factor/s that may mediate these effects. Our findings will establish a direct causal role for obesity in pancreatic cancer progression and identify molecular determinants that may drive this process, thereby delineating important pathways in the obesity-pancreatic cancer axis that may be therapeutically targeted in the future. [Supported by: The Advanced Medical Foundation] Citation Format: Roopali Roy, Marsha A. Moses. Adipocytes promote pancreatic cancer cell proliferation and progression. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5083. doi:10.1158/1538-7445.AM2015-5083

Immunoinflammatory diseases of the central nervous system - the tale of two cytokines.

Cytokines are potent mediators of cellular communication that have crucial roles in the regulation of innate and adaptive immunoinflammatory responses. Clear evidence has emerged in recent years that the dysregulated production of cytokines may in itself be causative in the pathogenesis of certain immunoinflammatory disorders. Here we review current evidence for the involvement of two different cytokines, IFN-α and IL-6, as principal mediators of specific immunoinflammatory disorders of the CNS. IFN-α belongs to the type I IFN family and is causally linked to the development of inflammatory encephalopathy exemplified by the genetic disorder, Aicardi-Goutières syndrome. IL-6 belongs to the gp130 family of cytokines and is causally linked to a number of immunoinflammatory disorders of the CNS including neuromyelitis optica, idiopathic transverse myelitis and genetically linked autoinflammatory neurological disease. In addition to clinical evidence, experimental studies, particularly in genetically engineered mouse models with astrocyte-targeted, CNS-restricted production of IFN-α or IL-6 replicate many of the cardinal neuropathological features of these human cytokine-linked immunoinflammatory neurological disorders giving crucial evidence for a direct causative role of these cytokines and providing further rationale for the therapeutic targeting of these cytokines in neurological diseases where indicated.

Surgical attenuation of spontaneous congenital portosystemic shunts in dogs resolves hepatic encephalopathy but not hypermanganesemia.

Hypermanganesemia is commonly recognized in human patients with hepatic insufficiency and portosystemic shunting. Since manganese is neurotoxic, increases in brain manganese concentrations have been implicated in the development of hepatic encephalopathy although a direct causative role has yet to be demonstrated. Evaluate manganese concentrations in dogs with a naturally occurring congenital shunt before and after attenuation as well as longitudinally following the changes in hepatic encephalopathy grade. Our study demonstrated that attenuation of the shunt resolved encephalopathy, significantly reduced postprandial bile acids, yet a hypermanganasemic state persisted. This study demonstrates that resolution of hepatic encephalopathy can occur without the correction of hypermanganesemia, indicating that increased manganese concentrations alone do not play a causative role in encephalopathy. Our study further demonstrates the value of the canine congenital portosystemic shunt as a naturally occurring spontaneous model of human hepatic encephalopathy.