A polymorphism of the interleukin-1 beta gene at position +3953 influences progression and neuro-pathological hallmarks of Alzheimer’s disease

DNA hypomethylation promotes the expression of CASPASE-4 which exacerbates inflammation and amyloid-β deposition in Alzheimer's disease

Alzheimer's disease (AD) is the sixth leading cause of death in the USA. It is established that neuroinflammation contributes to the synaptic loss, neuronal death, and symptomatic decline of AD patients. Accumulating evidence suggests a critical role for microglia, innate immune phagocytes of the brain. For instance, microglia release pro-inflammatory products such as IL-1β which is highly implicated in AD pathobiology. The mechanisms underlying the transition of microglia to proinflammatory promoters of AD remain largely unknown. To address this gap, we performed reduced representation bisulfite sequencing (RRBS) to profile global DNA methylation changes in human AD brains compared to no disease controls. We identified differential DNA methylation of CASPASE-4 (CASP4), which when expressed promotes the generation of IL-1β and is predominantly expressed in immune cells. DNA upstream of the CASP4 transcription start site was hypomethylated in human AD brains, which was correlated with increased expression of CASP4. Furthermore, microglia from a mouse model of AD (5xFAD) express increased levels of CASP4 compared to wild-type (WT) mice. To study the role of CASP4 in AD, we developed a novel mouse model of AD lacking the mouse ortholog of CASP4 and CASP11, which is encoded by mouse Caspase-4 (5xFAD/Casp4-/-). The expression of CASP11 was associated with increased accumulation of pathologic protein aggregate amyloid-β (Aβ) and increased microglial production of IL-1β in 5xFAD mice. Utilizing RNA-sequencing, we determined that CASP11 promotes unique transcriptomic phenotypes in 5xFAD mouse brains, including alterations of neuroinflammatory and chemokine signaling pathways. Notably, in vitro, CASP11 promoted generation of IL-1β from macrophages in response to cytosolic Aβ through cleavage of downstream effector Gasdermin D (GSDMD). Therefore, here we unravel the role for CASP11 and GSDMD in the generation of IL-1β in response to Aβ and the progression of pathologic inflammation in AD. Overall, our results demonstrate that overexpression of CASP4 due to differential DNA methylation in AD microglia contributes to the progression of AD pathobiology. Thus, we identify CASP4 as a potential target for immunotherapies for the treatment and prevention of AD.

DNA hypomethylation promotes the expression of CASPASE-4 which exacerbates neuroinflammation and amyloid-β deposition in Alzheimer's disease The Ohio State University College of Medicine

Alzheimer's Disease (AD) is the 6th leading cause of death in the US. It is established that neuroinflammation contributes to the synaptic loss, neuronal death, and symptomatic decline of AD patients. Accumulating evidence suggests a critical role for microglia, innate immune phagocytes of the brain. For instance, microglia release proinflammatory products such as IL-1β which is highly implicated in AD pathobiology. The mechanisms underlying the transition of microglia to proinflammatory promoters of AD remain largely unknown. To address this gap, we performed Reduced Representation Bisulfite Sequencing (RRBS) to profile global DNA methylation changes in human AD brains compared to no disease controls. We identified differential DNA methylation of CASPASE-4 (CASP4), which when expressed, can be involved in generation of IL-1β and is predominantly expressed in immune cells. DNA upstream of the CASP4 transcription start site was hypomethylated in human AD brains, which was correlated with increased expression of CASP4. Furthermore, microglia from a mouse model of AD (5xFAD) express increased levels of CASP4 compared to wild-type (WT) mice. To study the role of CASP4 in AD, we developed a novel mouse model of AD lacking the mouse ortholog of CASP4, CASP11, which is encoded by mouse Caspase-4 (5xFAD/Casp4-/-). The expression of CASP11 was associated with increased accumulation of pathologic protein aggregate amyloid-β (Aβ) and increased microglial production of IL-1β in 5xFAD mice. Utilizing RNA sequencing, we determined that CASP11 promotes unique transcriptomic phenotypes in 5xFAD mouse brains, including alterations of neuroinflammatory and chemokine signaling pathways. Notably, in vitro, CASP11 promoted generation of IL-1β from macrophages in response to cytosolic Aβ through cleavage of downstream effector Gasdermin D (G SDMD). We describe a role for CASP11 and GSDMD in the generation of IL-1β in response to Aβ and the progression of pathologic inflammation in AD. Overall, our results demonstrate that overexpression of CASP4 due to differential methylation in AD microglia contributes to the progression of AD pathobiology, thus identifying CASP4 as a potential target for immunotherapies for the treatment of AD.

Acute Pancreatitis and the Risk of Dementia in Diabetes: A Nationwide Cohort Study Using Korean Healthcare Claims Database

BACKGROUND

Diabetes is a major risk factor for the development of dementia, which has been proven to be associated with systemic inflammation. Acute pancreatitis, also a local and systemic inflammatory disease, is the most common gastrointestinal disease requiring acute hospitalization.

OBJECTIVE

The effect of acute pancreatitis on dementia was investigated in type 2 diabetic patients.

METHODS

Data was collected from the Korean National Health Insurance Service. The study sample included type 2 diabetes patients who received general health examination from 2009 to 2012. Cox proportional hazard regression analysis was used to evaluate the association between acute pancreatitis and dementia with adjustment of confounders. Stratified subgroup analysis by age, sex, smoking, alcohol consumption, hypertension, dyslipidemia, and body mass index was conducted.

RESULTS

Among the 2,328,671 participants in total, 4,463 patients had a history of acute pancreatitis before the health examination. During a median follow-up of 8.1 (IQR, 6.7-9.0) years, 194,023 participants (8.3%) developed all-cause dementia. Previous history of acute pancreatitis was a significant risk factor for dementia after adjustment of confounding variables (HR 1.39 [95% CI 1.26-1.53]). In the subgroup analysis, patient characteristics such as age under 65 years, male, current smoker, and alcohol consumption were significant risk factors for dementia in patients with a history of acute pancreatitis.

CONCLUSION

The history of acute pancreatitis was associated with the development of dementia in patients with diabetes. Because the risk of dementia increases with alcohol consumption and smoking in diabetic patients with history of acute pancreatitis, abstinence from alcohol and smoking should be recommended.

Hippocampal but Not Serum Cytokine Levels Are Altered by Traffic-Related Air Pollution in TgF344-AD and Wildtype Fischer 344 Rats in a Sex- and Age-Dependent Manner

Epidemiological studies have demonstrated that air pollution is a significant risk factor for age-related dementia, including Alzheimer's disease (AD). It has been posited that traffic-related air pollution (TRAP) promotes AD neuropathology by exacerbating neuroinflammation. To test this hypothesis, serum and hippocampal cytokines were quantified in male and female TgF344-AD rats and wildtype (WT) Fischer 344 littermates exposed to TRAP or filtered air (FA) from 1 to 15 months of age. Luminex™ rat 23-cytokine panel assays were used to measure the levels of hippocampal and serum cytokines in 3-, 6-, 10-, and 15-month-old rats (corresponding to 2, 5, 9, and 14 months of exposure, respectively). Age had a pronounced effect on both serum and hippocampal cytokines; however, age-related changes in hippocampus were not mirrored in the serum and vice versa. Age-related changes in serum cytokine levels were not influenced by sex, genotype, or TRAP exposure. However, in the hippocampus, in 3-month-old TgF344-AD and WT animals, TRAP increased IL-1ß in females while increasing TNF ɑin males. In 6-month-old animals, TRAP increased hippocampal levels of M-CSF in TgF344-AD and WT females but had no significant effect in males. At 10 and 15 months of age, there were minimal effects of TRAP, genotype or sex on hippocampal cytokines. These observations demonstrate that TRAP triggers an early inflammatory response in the hippocampus that differs with sex and age and is not reflected in the serum cytokine profile. The relationship of TRAP effects on cytokines to disease progression remains to be determined.

Polymorphisms in cytokine genes influence cognitive and functional performance in a population aged 75 years and above

OBJECTIVE

To investigate the frequency of the cytokine single nucleotide polymorphisms (SNPs) tumor necrosis factor (TNF)-α -308G > A, tumor growth factor (TGF)-β1 codon +10C > T, TGF-β1 codon +25G > C, interleukin (IL)-10 -1082A > G, IL-10 -819C > T, IL-10 -592C > A, IL-6 -174G > C, and IFN-γ +874T > A in a sample of healthy and cognitively impaired elderlies and to verify the probable association between these SNPs and cognitive and functional performance of subjects aged 75 years and above.

METHODS

259 Brazilian subjects were included, comprising 81 with cognitive impairment no dementia (CIND) and 54 demented seniors (together made up the cognitively impaired group, CI) and 124 age-matched and gender-matched cognitively healthy controls (CHS). The genotyping was performed by multiplex polymerase chain reaction. The cognitive performance was evaluated by Mini-Mental State Examination Brief Cognitive Screening Battery. The functional performance was accessed by Functional Activities Questionnaire.

RESULTS

The CC^lower genotype of TGF-β1 codon +25G > C was frequent in both patient groups. The TT^higher genotype of INF-γ +874T > A was less frequent in the dementia group. IL-10 haplotypes of lower expression were more frequent among CIND and demented patients. In CI, individuals with genetic variants that produce higher expression of TGF-β1, INF-γ, and IL-10 showed better normalized cognitive performance. Additionally, the A^lower allele of INF-γ +874T > A was related to worse functional performance in CI, while the A^lower allele of TNF-α -308G > A was associated with better cognitive and functional scores in the CIND group.

CONCLUSIONS

Our findings suggest a potential role for certain cytokine SNPs in the development of CIND and dementia, which may influence the functional and cognitive performance of these patients. Copyright © 2016 John Wiley & Sons, Ltd.

Inflammatory Cytokines and Alzheimer's Disease: A Review from the Perspective of Genetic Polymorphisms

Neuroinflammatory processes are a central feature of Alzheimer's disease (AD) in which microglia are over-activated, resulting in the increased production of pro-inflammatory cytokines. Moreover, deficiencies in the anti-inflammatory system may also contribute to neuroinflammation. Recently, advanced methods for the analysis of genetic polymorphisms have further supported the relationship between neuroinflammatory factors and AD risk because a series of polymorphisms in inflammation-related genes have been shown to be associated with AD. In this review, we summarize the polymorphisms of both pro- and anti-inflammatory cytokines related to AD, primarily interleukin-1 (IL-1), IL-6, tumor necrosis factor alpha, IL-4, IL-10, and transforming growth factor beta, as well as their functional activity in AD pathology. Exploration of the relationship between inflammatory cytokine polymorphisms and AD risk may facilitate our understanding of AD pathogenesis and contribute to improved treatment strategies.

Impaired regulation of immune responses in cognitive decline and Alzheimer’s disease: lessons from genetic association studies

Altered levels of cytokines and acute-phase proteins have been described in the blood and brain of patients with Alzheimer's disease. Microglia are resident cells of the brain and metabolic upregulation of these cells may play a crucial role in the development of the neurodegeneration associated with Alzheimer's disease. Studies focusing on gene polymorphisms of molecules with immune regulatory function have demonstrated an association with increased risk of the disease and confirmed the pivotal role of immune responses in Alzheimer's disease pathogenesis. Several gene variants may also influence the rate of the cognitive decline associated with the disease. A definite immune-related gene polymorphism profile may be a feature of a limited group of patients with early onset of the disease and fast clinical deterioration. Only this group of patients may benefit from anti-inflammatory treatment.

Association mapping of genetic risk factors for chronic wasting disease in wild deer

Chronic wasting disease (CWD) is a fatal transmissible spongiform encephalopathy affecting North American cervids. We assessed the feasibility of association mapping CWD genetic risk factors in wild white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) using a panel of bovine microsatellite markers from three homologous deer linkage groups predicted to contain candidate genes. These markers had a low cross-species amplification rate (27.9%) and showed weak linkage disequilibrium (<1 cM). Markers near the prion protein and the neurofibromin 1 (NF1) genes were suggestively associated with CWD status in white-tailed deer (P = 0.006) and mule deer (P = 0.02), respectively. This is the first time an association between the NF1 region and CWD has been reported.

Transgenic mouse models of Alzheimer disease: developing a better model as a tool for therapeutic interventions

Alzheimer disease (AD) is the leading cause of dementia among elderly. Currently, no effective treatment is available for AD. Analysis of transgenic mouse models of AD has facilitated our understanding of disease mechanisms and provided valuable tools for evaluating potential therapeutic strategies. In this review, we will discuss the strengths and weaknesses of current mouse models of AD and the contribution towards understanding the pathological mechanisms and developing effective therapies.

Psychotropic drug effects on gene transcriptomics relevant to Alzheimer disease

Psychotropics are widely prescribed in Alzheimer disease (AD) without regard to their pathobiological effects. Results summarize a comprehensive survey of psychotropic effects on messenger ribonucleic acid (mRNA) expression for 52 genes linked to AD. Pending future investigations, current data indicate that atypical antipsychotics, lithium, and fluoxetine reduce AD risk, whereas other drug classes promote risk. Risk may be attenuated by antipsychotics and lithium (down-regulate TNF), atypical antipsychotics (down-regulate TF), risperidone (down-regulates IL1B), olanzapine (up-regulates TFAM, down-regulates PRNP), fluoxetine (up-regulates CLU, SORCS1, NEDD9, GRN, and ECE1), and lithium coadministered with antipsychotics (down-regulates IL1B). Risk may be enhanced by neuroleptics (up-regulate TF), haloperidol (up-regulates IL1B and PION), olanzapine (down-regulates THRA and PRNP, up-regulates IL1A), and chlorpromazine, imipramine, maprotiline, fluvoxamine, and diazepam (up-regulate IL1B). There were no results for dextromethorphan-plus-quinidine. Fluoxetine effects on CLU, NEDD9, and GRN were statistically robust. Drug effects on specific variants, polymorphisms, genotypes, and other genes (CCR2, TF, and PRNP) are detailed. Translational AD risk applications and their limitations related to specific genes, mutations, variants, polymorphisms, genotypes, brain site, sex, clinical population, AD stage, and other factors are discussed. This report provides an initial summary and framework to understand the potential impact of psychotropic drugs on AD-relevant genes.

APOE epsilon-4 allele and cytokine production in Alzheimer's disease

OBJECTIVE

The APOE epsilon-4 allele has consistently emerged as a susceptibility factor for Alzheimer's disease (AD). Pro-inflammatory cytokines are detectable at abnormal levels in AD, and are thought to play a pathophysiological role. Animal studies have shown dose-dependent correlations between the number of APOE epsilon-4 alleles and the levels of pro-inflammatory cytokines. The aims of this study were to investigate the influence of APOE genotypes on TNF-alpha, IL-6, and IL-1beta secreted by peripheral blood mononuclear cells (PBMC) from human patients with AD and to analyze the correlation between cytokine production and AD clinical features.

METHODS

Outpatients with AD (n = 40) were clinically evaluated for cognitive decline (MMSE) and psychiatric symptoms (Cornell Scale for Depression in Dementia; Neuropsychiatric Inventory) and genotyped for APOE variants. PBMCs were isolated from the donors and used to assess spontaneous and PMA-stimulated secretion of TNF-alpha, IL-6, and IL-1beta. Cytokine production was determined by immuno-enzymatic assays (ELISA).

RESULTS

In comparison with their counterparts without APOE4, patients with at least one copy of the APOE epsilon-4 allele showed higher spontaneous (p = 0.037) and PMA-induced (p = 0.039) production of IL-1beta after controlling for clinical variables. Significant correlations were reported between NPI scores (psychotic symptoms) and IL-6 production.

CONCLUSION

These preliminary findings suggest the involvement of inflammatory response in the pathogenic effect of the APOE epsilon-4 allele in AD, although their replication in larger samples is mandatory. The modest correlations between pro-inflammatory cytokines released at peripheral level and AD features emphasizes the need for further research to elucidate the role of neuroinflammation in pathophysiology of AD.

Interleukin-1beta: a bridge between inflammation and excitotoxicity?

Interleukin-1 (IL-1) is a proinflammatory cytokine released by many cell types that acts in both an autocrine and/or paracrine fashion. While IL-1 is best described as an important mediator of the peripheral immune response during infection and inflammation, increasing evidence implicates IL-1 signaling in the pathogenesis of several neurological disorders. The biochemical pathway(s) by which this cytokine contributes to brain injury remain(s) largely unidentified. Herein, we review the evidence that demonstrates the contribution of IL-1beta to the pathogenesis of both acute and chronic neurological disorders. Further, we highlight data that leads us to propose IL-1beta as the missing mechanistic link between a potential beneficial inflammatory response and detrimental glutamate excitotoxicity.

Association between genetic variants of IL-1beta, IL-6 and TNF-alpha cytokines and cognitive performance in the elderly general population of the MEMO-study

This study is to investigate the associations between specific polymorphisms in three cytokine genes and domains of cognitive functioning in a population based study in the elderly. In a cross-sectional study of 369 community dwelling elderly subjects we examined the relationships between the polymorphisms IL-1beta-1418C-->T, IL-6-572G-->C and TNF-alpha-308G-->A and the cognitive function domains memory, processing speed and motor function using an extensive neuropsychological test battery. Linear regression models were used in the analysis and results adjusted for multiple comparisons. A significant association between the IL-1beta-1418C-->T polymorphism and memory performance was found with carriers of the T allele (dominant model) having worse memory performance than those with the C allele. In addition, a significant association between the TNF-alpha-308G-->A polymorphism and processing speed was observed, indicating better performance for heterozygous or homozygous carriers of the A allele. These results remained significant after adjustment for known confounders of cognitive function and additional Bonferroni correction for multiple comparisons. Our study provides first results on detrimental effects of the IL-1beta-1418C-->T polymorphism on memory performance and neuroprotective effects of the TNF-alpha-308G-->A polymorphism on processing speed in elderly individuals. Further research is needed to prospectively examine changes in cognitive performance in relation to cytokine genotypes.

Interleukin 1 beta gene polymorphism and risk of cervical cancer

OBJECTIVE

To determine whether a polymorphism at position +3953 in exon 5 of the lL-1beta gene (IL-1beta +3953), a condition associated with an increased risk for a number of inflammatory diseases, is also involved in the development of cervical cancer.

METHOD

We isolated DNA from peripheral blood in 150 women with cervical cancer and 200 healthy controls, and IL-1beta +3953 allele polymorphism was determined by polymerase chain reaction.

RESULTS

Genotypes A1/A2 and A2/A2+A1/A2 were associated with increased risk of cervical cancer (odds ratio [OR], 2.88; 95% confidence interval [CI], 1.78-4.67; P<0.001 and OR, 2.85; 95% CI, 1.77-4.6; P<0.001, respectively). The risk in a passive smoker with A2/A2 or A1/A2 genotype was increased more than 5-fold (OR, 5.69; 95% CI, 2.61-12.50; P<0.001) compared with a nonsmoker with the A1/A1 genotype.

CONCLUSION

This study provides evidence of an association between lL-1beta +3953 polymorphism and risk of cervical cancer.

Association of interleukin-1beta and interleukin-1 receptor antagonist polymorphisms with bacterial vaginosis in non-pregnant Italian women

Bacterial vaginosis (BV) is the most prevalent alteration of vaginal microflora worldwide. BV is a polymicrobial disorder, and its etiology is elusive. Factors predisposing to this recurrent condition are not fully characterized. We aimed to investigate whether interleukin-1beta (IL-1beta) and IL-1 receptor antagonist (IL-1ra) polymorphisms are associated with BV in non-pregnant white Italian women. Genomic DNA was obtained from 164 BV positive, and 406 control women. Two diallelic polymorphisms in the IL-1beta gene (IL-1B) representing C/T base transitions at - 511 and + 3954 positions and a variable number tandem repeats (VNTR) in intron 2 of the IL-1ra gene (IL-1RN) were assessed. We demonstrated that women who were homozygous for - 511 CC or + 3954 TT of the IL-1B gene were at increased risk for BV with an odds ratio (OR) = 1.5 [95% confidence interval (CI) = 1.03-2.14, P = 0.032], and OR = 2.8 (95% CI = 1.37-5.88, P = 0.004), respectively. The haplotype - 511/ + 3954 T-C was protective for BV, with an OR = 0.7 (95% CI = 0.49-0.90, P = 0.009). The IL-1RN VNTR genotype was not associated with BV, although the rare allele 3 showed a trend towards protection (P = 0.049). These data show that host genetic variants at the IL-1beta locus predispose to BV among Caucasian non-pregnant women. Further studies will determine whether these genetic polymorphisms modulate the risk for BV recurrence, and/or BV associated severe adverse outcomes as preterm birth and human immunodeficiency virus transmission.

IL-1 family members as candidate genes modulating scrapie susceptibility in sheep: localization, partial characterization, and expression

Scrapie (SC) is a transmissible spongiform encephalopathy (TSE) in sheep and goats. Susceptibility to this neurodegenerative disease is controlled mainly by point mutations at the PRNP locus. Other genes, apart from PRNP, have been reported to modulate resistance/susceptibility to SC. On the basis of several studies on Alzheimer's disease and different TSE models, and of requirement for correct homeostasis of cytokines in brain, IL1B and IL1RN were chosen as putative positional and functional candidate genes that might be involved in the polygenic variance mentioned above. In the present work, ovine IL1B and IL1RN genes were partially isolated and characterized, including promoter and other regulatory regions. In addition, several sequence polymorphisms were identified. Furthermore, their cytogenetic positions on sheep chromosomes were determined by FISH and confirmed by linkage analysis, localizing both genes in OAR3p22, a region previously described as carrying a QTL for SC incubation period in sheep. Finally, expression analyses were carried out in eight naturally SC-infected and five uninfected sheep with the same genotype for PRNP (ARQ/ARQ). This comparison was performed using real-time RT-PCR in samples of spleen and cerebellum. Results showed differences in the expression of both cytokines in cerebellum (p < 0.05) but not in spleen (p > 0.05).

(Peri)vascular production and action of pro-inflammatory cytokines in brain pathology

In response to tissue injury or infection, the peripheral tissue macrophage induces an inflammatory response through the release of IL-1β (interleukin-1β) and TNFα (tumour necrosis factor α). These cytokines stimulate macrophages and endothelial cells to express chemokines and adhesion molecules that attract leucocytes into the peripheral site of injury or infection. The aims of the present review are to (i) discuss the relevance of brain (peri)vascular cells and compartments to bacterial meningitis, HIV-1-associated dementia, multiple sclerosis, ischaemic and traumatic brain injury, and Alzheimer's disease, and (ii) to provide an overview of the production and action of pro-inflammatory cytokines by (peri)vascular cells in these pathologies of the CNS (central nervous system). The brain (peri)vascular compartments are highly relevant to pathologies affecting the CNS, as infections are almost exclusively blood-borne. Insults disrupt blood and energy flow to neurons, and active brain-to-blood transport mechanisms, which are the bottleneck in the clearance of unwanted molecules from the brain. Perivascular macrophages are the most reactive cell type and produce IL-1β and TNFα after infection or injury to the CNS. The main cellular target for IL-1β and TNFα produced in the brain (peri)vascular compartment is the endothelium, where these cytokines induce the expression of adhesion molecules and promote leucocyte infiltration. Whether this and other effects of IL-1 and TNF in the brain (peri)vascular compartments are detrimental or beneficial in neuropathology remains to be shown and requires a clear understanding of the role of these cytokines in both damaging and repair processes in the CNS.

Interleukin-1β and Serotonin Transporter Gene Polymorphisms in Burning Mouth Syndrome Patients

Burning mouth syndrome (BMS) is a chronic pain syndrome that encompasses all forms of burning sensations in the oral cavity when the oral mucosa is clinically normal. Neural, psychologic, and cytokine factors may be implicated in the pathogenesis of BMS. There are no studies of genetic factors associated with psychologic behavior and cytokine pain sensitivity in BMS patients. The purpose of the present study was to investigate a possible association between functional genetic polymorphisms, +3,954 (C/T) interleukin-1beta, and the polymorphic site on promoter region of the serotonin transporter gene (5-HTTLPR) in a sample of Brazilian patients. Thirty patients affected by BMS and 31 healthy volunteers were genotyped for 5-HTTLPR and IL-1beta gene. The chi-squared test was used for statistical analysis. There was no statistical difference in 5-HTTLPR genotypes between the case and control groups (P = .60), however a significant increase was observed in the IL-1beta high production genotype CT in BMS subjects (P = .005). In conclusion, the present study shows association between BMS and IL-1beta high producer genotype.

PERSPECTIVE

This article shows evidence that genetic polymorphisms associated with IL-1beta high production genotype are implicated on the pathogenesis of BMS. The modulation of IL1beta production may be an interesting tool in BMS management.

Single nucleotide polymorphisms in the human interleukin-1B gene affect transcription according to haplotype context

We questioned the significance of haplotype structure in gene regulation by testing whether individual single nucleotide polymorphisms (SNPs) within a gene promoter region [interleukin-1-beta (IL1B)] might affect promoter function and, if so, whether function was dependent on haplotype context. We sequenced genomic DNA from 25 individuals of diverse ethnicity, focusing on exons and upstream flanking regions of genes of the cluster. We identified four IL1B promoter region SNPs that were active in transient transfection reporter gene assays. To substantiate allelic differences found in reporter gene assays, we also examined nuclear protein binding to promoter sequence oligonucleotides containing different alleles of the SNPs. The effect of individual SNPs on reporter gene transcription varied according to which alleles of the three other SNPs were present in the promoter construct. The SNP patterns that influenced function reflected common haplotypes that occur in the population, suggesting functionally significant interactions between SNPs according to haplotype context. Of the haplotypes that include the four functional IL1B promoter SNPs (-3737, -1464, -511, -31), the four haplotypes that showed different contextual effects on SNP function accounted for >98% of the estimated haplotypes in Caucasian and African-American populations. This finding underlines the importance of understanding the haplotype structure of populations used for genetic studies and may be especially important in the functional analysis of genetic variation across gene regulatory regions.

Interleukins, inflammation, and mechanisms of Alzheimer's disease

Alzheimer's disease (AD) is the most common progressive neurodegenerative form of dementia in the elderly and is characterized neuropathologically by neurofibrillary tangles (NFT), amyloid neuritic plaques (NP), and prominent synaptic and eventually neuronal loss. Although the molecular basis of AD is not clearly understood, a neuroinflammatory process, triggered by Abeta42, plays a central role in the neurodegenerative process. This inflammatory process is driven by activated microglia, astrocytes and the induction of proinflammatory molecules and related signaling pathways, leading to both synaptic and neuronal damage as well as further inflammatory cell activation. Epidemiologic data as well as clinical trial evidence suggest that nonsteroidal anti-inflammatory drug (NSAID) use may decrease the incidence of AD, further supporting a role for inflammation in AD pathogenesis. Although the precise molecular and cellular relationship between AD and inflammation remains unclear, interleukins and cytokines might induce activation of signaling pathways leading to futher inflammation and neuronal injury. This chapter will discuss the association between interleukins and neurodegeneration in AD and highlight the significance of genetic and clinical aspects of interleukins in disease expression and progression. As part of an emerging inflammatory signaling network underlying AD pathogenesis, beta-amyloid (Abeta) stimulates the glial and microglial production of interleukins and other cytokines, leading to an ongoing inflammatory cascade and contributing to synaptic dysfunction and loss, and later, neuronal death. Inflammatory pathways involving interleukin and cytokine signaling might suggest potential targets for intervention and influence the development of novel therapies to circumvent synaptic and neuronal dysfunction ultimately leading to AD neurodegeneration.

Postoperative Cognitive Dysfunction After Cardiac Surgery

Prolonged postoperative cognitive dysfunction (POCD) is reported to occur frequently after cardiac surgery. However, it is rarely assessed in routine clinical practice and receives little attention. Although the cerebral consequences of cardiopulmonary bypass have been measured clinically, insights into the resulting molecular and pathologic events within the brain have only begun to be investigated. POCD is likely to impair quality of life and constitutes a large burden on society when elderly patients prematurely lose their independence. Numerous studies have reported that neurocognitive deficit is associated with heightened mortality, increased length of hospital stay, and discharge to a nursing home. This is linked with a tremendous demand for health-care resources. Because of the magnitude of the clinical problem, serious consideration must be directed toward understanding its etiology and the development of neuroprotective strategies. Clearly identifying the mechanisms of POCD is challenging. The purpose of this review is to discuss recent developments in our understanding of the pathophysiologic mechanisms, prevention, and treatments that have been designed to ameliorate brain dysfunction after cardiac surgery.

To be or not to be (inflamed) – is that the question in anti-inflammatory drug therapy of neurodegenerative disorders?

A sustained inflammatory reaction is present in acute (e.g. stroke) and chronic (e.g. Alzheimer's disease, Parkinson's disease and multiple sclerosis) neurodegenerative disorders. Inflammation, which is fostered by both residential glial cells and blood-circulating cells that infiltrate the diseased brain, probably starts as a time- and site-specific defense mechanism that could later evolve into a destructive and uncontrolled reaction. In this article, we review the crucial dichotomy of brain inflammation, where failure to resolve an acute beneficial response could lead to a vicious and anarchic state of chronic activation. The possible use of non-steroidal anti-inflammatory drugs for the management of neurodegenerative diseases is discussed in light of recent data demonstrating a neuroprotective role of local innate and adaptive immune responses. Novel therapeutic approaches must rely on potentiation of endogenous anti-inflammatory pathways, identification of early markers of neuronal deterioration and a combination treatment involving immune modulation and anti-inflammatory therapies.

Role of inflammation in neurodegenerative diseases

PURPOSE OF REVIEW

Inflammation is a self-defensive reaction aimed at eliminating or neutralizing injurious stimuli, and restoring tissue integrity. In neurodegenerative diseases inflammation occurs as a local response driven by microglia, in the absence of leucocyte infiltration. Like peripheral inflammation, neuroinflammation may become a harmful process, and it is now widely accepted that it may contribute to the pathogenesis of many central nervous system disorders, including chronic neurodegenerative diseases. This review addresses some of the most recent advances in our understanding of neuroinflammation.

RECENT FINDINGS

The presence of activated microglia surrounding amyloid plaques and increased levels of complement elements, cytokines, chemokines and free radicals support the existence of a self-propagating toxic cycle and provide a rationale for anti-inflammatory approaches to prevent or delay neurodegeneration. Nonetheless, recent studies have provided evidence that chronic stimulation leads microglia to acquire an anti-inflammatory phenotype, characterized by activated morphology and induction of neuroprotective and immunoregulatory molecules. The causes and consequences of this atypical phenotype have just begun to be unravelled.

SUMMARY

Although significant advances have been made in our knowledge of degenerative diseases, there remains controversy regarding whether neuroinflammation and microglial activation are beneficial or detrimental. Strategies aimed at both preventing and boosting microglial activation are presently under investigation, and these studies might reveal new potentially effective treatments for these neurological disorders.