Genetic polymorphisms of serum amyloid A1 and coronary artery disease risk
TISSUE ANTIGENS
Authors: Xie, X.; Ma, Y-T.; Yang, Y-N.; Li, X-M.; Zheng, Y-Y.; Liu, F.; Ma, X.; Fu, Z-Y.; Yu, Z-X.; Chen, Y.; Chen, B-D.; Huang, Y.
Abstract
Serum amyloid A (SAA) protein is not only an inflammatory factor but also an apolipoprotein that can replace apolipoprotein A1 (apoA1) as the major apolipoprotein of high-density lipoprotein cholesterol (HDL-C). However, the relationship between genetic polymorphisms of SAA and coronary artery disease (CAD) remains unclear. A total of four single nucleotide polymorphisms (rs12218, rs4638289, rs7131332, and rs11603089) of the SAA gene were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in two independent case-control studies, one of the Han population (1416 CAD patients and 1373 control subjects) and the other of the Uygur population (588 CAD patients and 529 control subjects). We found that the rs12218 CC genotype was more frequent among the CAD patients than among the controls in both the Han (8.3% vs. 4.8%, P<0.001) and Uygur populations (15.5% vs. 11.3%, P<0.05). After adjustments for confounding factors, such as sex, age, smoking, drinking, hypertension, diabetes, and serum levels of triglycerides, total cholesterol, HDL, and plasma SAA, the differences remained significant in the Han (CC vs. CT+TT, P<0.001, OR=3.863, 95% CI: 1.755-12.477) and Uygur groups (CC vs. CT+TT, P=0.031, OR=3.022, 95% CI: 1.033-8.840). Genetic polymorphisms in SAA1 are associated with CAD in the Han and Uygur populations in western China.
Organization and Biology of the Porcine Serum Amyloid A (SAA) Gene Cluster: Isoform Specific Responses to Bacterial Infection
PLOS ONE
Authors: Olsen, Helle G.; Skovgaard, Kerstin; Nielsen, Ole L.; Leifsson, Pall S.; Jensen, Henrik E.; Iburg, Tine; Heegaard, Peter M. H.
Abstract
Serum amyloid A (SAA) is a prominent acute phase protein. Although its biological functions are debated, the wide species distribution of highly homologous SAA proteins and their uniform behavior in response to injury or inflammation in itself suggests a significant role for this protein. The pig is increasingly being used as a model for the study of inflammatory reactions, yet only little is known about how specific SAA genes are regulated in the pig during acute phase responses and other responses induced by pro-inflammatory host mediators. We designed SAA gene specific primers and quantified the gene expression of porcine SAA1, SAA2, SAA3, and SAA4 by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) in liver, spleen, and lung tissue from pigs experimentally infected with the Gram-negative swine specific bacterium Actinobacillus pleuropneumoniae, as well as from pigs experimentally infected with the Gram-positive bacterium Staphylococcus aureus. Our results show that: 1) SAA1 may be a pseudogene in pigs; 2) we were able to detect two previously uncharacterized SAA transcripts, namely SAA2 and SAA4, of which the SAA2 transcript is primarily induced in the liver during acute infection and presumably contributes to circulating SAA in pigs; 3) Porcine SAA3 transcription is induced both hepatically and extrahepatically during acute infection, and may be correlated to local organ affection; 4) Hepatic transcription of SAA4 is markedly induced in pigs infected with A. pleuropneumoniae, but only weakly in pigs infected with S. aureus. These results for the first time establish the infection response patterns of the four porcine SAA genes which will be of importance for the use of the pig as a model for human inflammatory responses, e. g. within sepsis, cancer, and obesity research.