Mapping, genetic isolation, and characterization of genetic loci that determine resistance to atherosclerosis in C3H mice
ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY
Authors: Wang, Susanna S.; Shi, Weibin; Wang, Xuping; Velky, Leandra; Greenlee, Sarah; Wang, Min T.; Drake, Thomas A.; Lusis, Aldons J.
Abstract
Objective-C3H/HeJ (C3H) mice are extremely resistant to atherosclerosis. To identify the genetic factors involved in lesion initiation, we studied a cross between C3H and the susceptible strain C57BL/6J (B6) on a hyperlipidemic ( apolipoprotein E - null) background. Methods and Results-Whereas a previous cross in mice fed a Western diet for 16 weeks revealed a very complex inheritance pattern with many significant lesion QTLs, the present cross, on a chow diet, revealed a single major locus on chromosome 9 (lod = 5.0, Ath29*), and a suggestive locus on chromosome 4 (lod = 2.6, Ath8). QTLs for plasma HDL, total cholesterol, and triglyceride levels were found on chromosome 1 over the ApoA2 gene. Neither of the lesion QTLs were associated with differences in plasma lipid levels or other systemic risk factors, consistent with the concept that genetic factors affecting cellular functions of the vessel wall are important determinants of atherosclerosis susceptibility. We generated a congenic strain for Ath29 and confirmed its contribution to lesion development. Toll-like receptor 4 (Tlr4), the lipopolysaccharide (LPS) receptor, is located in the Ath8 region and is known to be defective in C3H/HeJ mice. We constructed a congenic strain carrying a normal Tlr4 gene on the C3H Apoe-null background and found that the defective Tlr4 does not contribute significantly to lesion resistance during early lesion development. Conclusions-We identified one major QTL on chromosome 9, Ath29, for early lesion development in the BXH ApoE(-/-) cross fed on a chow diet and confirmed its contribution in congenic mice. We have also determined that Tlr4 on the C3H ApoE(-/-) background does not contribute to early lesion development. *Ath29 is referred to as Ath22 in Su et al 2006.
Plasma Apolipoprotein Levels Are Associated with Cognitive Status and Decline in a Community Cohort of Older Individuals
PLOS ONE
Authors: Song, Fei; Poljak, Anne; Crawford, John; Kochan, Nicole A.; Wen, Wei; Cameron, Barbara; Lux, Ora; Brodaty, Henry; Mather, Karen; Smythe, George A.; Sachdev, Perminder S.
Abstract
Objectives: Apolipoproteins have recently been implicated in the etiology of Alzheimer's disease (AD). In particular, Apolipoprotein J (ApoJ or clusterin) has been proposed as a biomarker of the disease at the pre-dementia stage. We examined a group of apolipoproteins, including ApoA1, ApoA2, ApoB, ApoC3, ApoE, ApoH and ApoJ, in the plasma of a longitudinal community based cohort. Methods: 664 subjects (257 with Mild Cognitive Impairment [MCI] and 407 with normal cognition), mean age 78 years, from the Sydney Memory and Aging Study (MAS) were followed up over two years. Plasma apolipoprotein levels at baseline (Wave 1) were measured using a multiplex bead fluorescence immunoassay technique. Results: At Wave 1, MCI subjects had lower levels of ApoA1, ApoA2 and ApoH, and higher levels of ApoE and ApoJ, and a higher ApoB/ApoA1 ratio. Carriers of the apolipoprotein E epsilon 4 allele had significantly lower levels of plasma ApoE, ApoC3 and ApoH and a significantly higher level of ApoB. Global cognitive scores were correlated positively with ApoH and negatively with ApoJ levels. ApoJ and ApoE levels were correlated negatively with grey matter volume and positively with cerebrospinal fluid (CSF) volume on MRI. Lower ApoA1, ApoA2 and ApoH levels, and higher ApoB/ApoA1 ratio, increased the risk of cognitive decline over two years in cognitively normal individuals. ApoA1 was the most significant predictor of decline. These associations remained after statistically controlling for lipid profile. Higher ApoJ levels predicted white matter atrophy over two years. Conclusions: Elderly individuals with MCI have abnormal apolipoprotein levels, which are related to cognitive function and volumetric MRI measures cross-sectionally and are predictive of cognitive impairment in cognitively normal subjects. ApoA1, ApoH and ApoJ are potential plasma biomarkers of cognitive decline in non-demented elderly individuals.