No Evidence for Cardiac Dysfunction in Kif6 Mutant Mice
Citation: Hameed A, Bennett E, Ciani B, Hoebers LPC, Milner R, et al. (
No Evidence for Cardiac Dysfunction in Kif6 Mutant Mice
Abdul Hameed 0
Ellen Bennett 0
Barbara Ciani 0
Loes P. C. Hoebers 0
Roy Milner 0
Allan Lawrie 0
Sheila E. Francis 0
Andrew J. Grierson 0
Katriina Aalto-Setala, University of Tampere, Finland
0 1 Department of Cardiovascular Science, Medical School, University of Sheffield , Sheffield , United Kingdom , 2 Sheffield Institute for Translational Neuroscience, University of Sheffield , Sheffield , United Kingdom , 3 Department of Chemistry, University of Sheffield , Sheffield , United Kingdom
A KIF6 variant in man has been reported to be associated with adverse cardiovascular outcomes after myocardial infarction. No clear biological or physiological data exist for Kif6. We sought to investigate the impact of a deleterious KIF6 mutation on cardiac function in mice. Kif6 mutant mice were generated and verified. Cardiac function was assessed by serial echocardiography at baseline, after ageing and after exercise. Lipid levels were also measured. No discernable adverse lipid or cardiac phenotype was detected in Kif6 mutant mice. These data suggest that dysfunction of Kif6 is linked to other more complex biological/biochemical parameters or is unlikely to be of material consequence in cardiac function.
-
Funding: This study was supported by the Research and Innovation Fund, University of Sheffield. The funders had no role in study design, data collection and
analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
. These authors contributed equally to this work.
There has been considerable debate within the cardiovascular
community regarding the role of kinesin-like protein 6 (Kif6) in
coronary artery disease. Initial reports using a candidate gene
based approach in several atherosclerosis population cohorts
observed an increase risk of adverse coronary events in carriers of
the rs20455 C variant in the KIF6 gene which leads to
a Trp719Arg substitution in the Kif6 protein [1,2,3,4]. These
findings were controversial and refuted by a large GWAS
metaanalysis using 19 case-control studies [5] where cases were defined
either by a history of prior myocardial infarction and/or the
presence of coronary artery disease at angiography. Furthermore
no association between the kif6 variant and coronary events was
observed in the most recent large meta-analysis [6]. However,
evidence from interventional randomized controlled trials (RCTs)
with statins associated carriage of this genotype with a greater
clinical response to statin therapy [7,8,9,10]. As a clinical test
based on KIF6 genotype was already on the market, the utility and
clinical significance of this was in doubt [11,12]. More recently,
retrospective analyses from several large independent RCTs
[13,14,15,16,17] have not observed an increased risk of adverse
vascular events or an attenuated response to statin therapy
amongst Kif6 719Arg carriers. In an attempt to reconcile these
discrepant findings, Ference et al hypothesized that the rs20455 C
variant in the KIF6 gene may influence LDL levels. By performing
a regression meta-analysis involving almost 145,000 patients, they
reported that carriers demonstrated greater reductions in LDL,
when treated with statins and consequently greater reduction in
clinical events when compared to non-carriers [6].
Kif6 is a member of the Kinesin 9 superfamily but the precise
molecular function of Kif6 is not known. It is likely to play a role in
the cellular transport of proteins along microtubules [18,19] and
could plausibly be involved in cellular transport in the
cardiovascular system. Hitherto, all studies have focused on investigating
polymorphism in the KIF6 gene within the context of coronary
artery disease yet to our knowledge there has been no investigation
(experimental or clinical) into its function (if any) on heart
function. We hypothesised that if loss of Kif6 function was
associated with cardiovascular disease, then mice with a deleterious
mutation in the Kif6 motor domain may exhibit defects in cardiac
physiology.
Therefore, we identified mice with an N-ethyl-N-nitrosourea
(ENU) induced mutation in the Kif6 motor, and investigated the
structural and functional cardiac phenotypes by high frequency
transthoracic echocardiography.
Kif6 mutant mice were obtained from the RIKEN Bioresource
Centre (Japan, RBRC03194), backcrossed 5 generations to
C57BL/6 and classed as incipient congenics. The likelihood that
a phenotype would arise because of a confounding mutation in the
RIKEN library is statistically slim (p,0.002) [20].
RT-PCR and Western blot analysis of Kif6 expression was
performed according to standard methods [21]. A rabbit
polyclonal antibody (Kif6 C165) was generated using a peptide
containing 20 C-terminal amino acids of human Kif6 as an
immunogen. Specificity of the antibody was demonstra (...truncated)