ABSTRACT
BACKGROUND: In the present study we determined whether the cystatin c gene (CST3) is genetically associated with late-onset Alzheimer's disease (AD). METHODS: Two informative flanking single nucleotide polymorphisms (SNP), rs2424577 and rs3827143, of the CST3 gene and apolipoprotein E (APOE) gene were assessed in 568 Finnish AD patients and 688 cognitively healthy controls. Samples were genotyped with the TaqMan technique, and we conducted a single allele and genotypic distribution comparison as well as an estimation of haplotype frequencies between cases and controls. RESULTS: The APOE genotype distribution differed as expected between the AD cases and controls (p < 0.001). On the whole, any significant differences in AD risk were not found in single SNP and haplotype analyses for the CST3 gene between the whole study cohorts or in the stratified subgroups. Interestingly, AG-genotype carriers of rs3827143 showed a significant difference (p = 0.04) between cases and controls when compared to AA-genotype carriers, but this finding remained insignificant in the adjusted model. CONCLUSION: Although flanking SNP cover the whole gene transcript with strong linkage disequilibrium, our data show that the CST3 gene is not associated with AD risk in the Finnish population.
Subject(s)
Alzheimer Disease/epidemiology , Alzheimer Disease/genetics , Cystatin C/genetics , Aged , Apolipoproteins E/genetics , Cohort Studies , Female , Finland/epidemiology , Gene Frequency , Genetic Markers , Genotype , Humans , Linkage Disequilibrium/genetics , Male , Polymorphism, Single Nucleotide , Risk AssessmentABSTRACT
BACKGROUND/AIMS: Fatty infiltration initiates alcohol-induced liver changes and complement component C3 affects lipid metabolism. We recently observed that ethanol-induced steatosis seen in normal (C3(+/+)) mice was absent in livers of C3-deficient (C3(-/-)) mice. To understand the underlying molecular mechanisms we analyzed lipid parameters and liver gene expression profiles in these mice. METHODS: A Western-type high-fat diet with ethanol or carbohydrates (control) was fed for 6 weeks to C3(+/+) and C3(-/-) mice. Serum and liver lipid parameters were analyzed and liver mRNA expression patterns studied by micro-array analysis and RT-PCR. RESULTS: In both genotypes ethanol markedly reduced serum cholesterol, apolipoprotein A-I, phospholipid transfer protein activity and hepatic mRNA levels of fatty acid-binding proteins and fatty acid beta-oxidation enzymes. In contrast, exclusively in C3(-/-) mice, ethanol treatment increased serum and liver adiponectin levels but down-regulated transcripts of lipogenic enzymes, adiponectin receptor 2 and adipose differentiation-related protein and up-regulated phospholipase D1. CONCLUSIONS: We propose that these ethanol-induced alterations observed exclusively in C3(-/-) mice contribute to protection against fatty infiltration and subsequent inflammatory processes in the liver of these mice. The results suggest important cross-talk between complement factor C3 and lipid regulators in ethanol-induced steatosis.
Subject(s)
Complement C3/deficiency , Fatty Liver, Alcoholic/genetics , Fatty Liver, Alcoholic/metabolism , Gene Expression , Liver/metabolism , Adiponectin/metabolism , Animals , Biosynthetic Pathways/drug effects , Complement C3/genetics , Complement C3/metabolism , Dietary Fats/administration & dosage , Ethanol , Fatty Liver, Alcoholic/pathology , Interleukin-10/blood , Lipid Metabolism , Liver/drug effects , Liver/pathology , Liver Cirrhosis, Experimental/chemically induced , Liver Cirrhosis, Experimental/genetics , Liver Cirrhosis, Experimental/metabolism , Liver Cirrhosis, Experimental/pathology , Mice , Mice, Inbred C57BL , Mice, Knockout , Oligonucleotide Array Sequence Analysis , RNA/genetics , Tumor Necrosis Factor-alpha/metabolismABSTRACT
The complement system can promote tissue damage or play a homeostatic role in the clearance and disposal of damaged tissue. We assessed the role of the terminal complement pathway in alcohol-induced liver damage in complement C6 (C6-/-) genetically deficient rats. C6-/- and corresponding C6+/+ rats were continuously exposed to ethanol by feeding ethanol-supplemented liquid diet for six weeks. Liver samples were analyzed for histopathology and complement component deposition by immunofluorescence microscopy. Prostaglandin E receptors and cytokine mRNA levels were analyzed by RT-PCR and plasma cytokines by ELISA. Deposition of complement components C1, C3, C8 and C9 was observed in C6+/+ rats, but not in C6-/- animals. The histopathological changes, the liver weight increase and the elevation of the plasma pro-/anti-inflammatory TNF-alpha/IL-10 ratio were, on the other hand, more marked in C6-/- rats. Furthermore, ethanol enhanced the hepatic mRNA expression of the prostaglandin E receptors EP2R and EP4R exclusively in the C6-/- rats. Our results indicate that a deficient terminal complement pathway predisposes to tissue injury and promotes a pro-inflammatory cytokine response. This suggests that an intact complement system has a protective function in the development of alcoholic liver damage.
Subject(s)
Alcoholism/complications , Complement System Proteins/immunology , Liver Diseases, Alcoholic/immunology , Liver/immunology , Alcoholism/immunology , Alcoholism/metabolism , Alcoholism/pathology , Animals , Complement C6/genetics , Complement C6/immunology , Complement C6/metabolism , Complement System Proteins/genetics , Complement System Proteins/metabolism , Cytokines/immunology , Cytokines/metabolism , Disease Models, Animal , Liver/metabolism , Liver/pathology , Liver Diseases, Alcoholic/etiology , Liver Diseases, Alcoholic/metabolism , Liver Diseases, Alcoholic/pathology , Liver Function Tests , Male , Organ Size , RNA, Messenger/metabolism , Rats , Rats, Inbred Strains , Receptors, Prostaglandin/immunology , Receptors, Prostaglandin/metabolism , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
The purpose of this study was to evaluate the possible contribution of complement-mediated inflammation to the development of alcoholic liver disease. Male Wistar rats were fed ethanol by liquid diet in a model that results in continuous ethanol intoxication and induces early signs of alcoholic liver injury. After a six-week study period liver samples were analyzed for the deposition of complement components (C1, C3, and C8) and expression of cell membrane-bound regulators (Crry and CD59). Activation of the homologous complement system in vitro was tested by treating frozen liver sections with normal rat serum (NRS). Immunohistochemical analysis showed deposits of C8 in the liver sections of ethanol-treated rats. When frozen liver sections from these rats were treated with NRS, periportal deposition of both C3 and C8, but only slight C1 deposition, was observed. Immunohistochemical and Western blot analysis both revealed a reduced expression of the complement regulators Crry and CD59. These results suggest an induction of complement-activating capacity in the liver after chronic ethanol treatment. Lack of C1 deposition in the lesions suggests that complement activation occurs primarily via the alternative pathway. The reduced expression of the critical complement regulatory proteins Crry and CD59 may sensitize the liver to complement-mediated damage.
