Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Genome-Wide Association Study in BRCA1 Mutation Carriers Identifies Novel Loci Associated with Breast and Ovarian Cancer Risk

BRCA1-associated breast and ovarian cancer risks can be modified by common genetic variants. To identify further cancer risk-modifying loci, we performed a multi-stage GWAS of 11,705 BRCA1 carriers (of whom 5,920 were diagnosed with breast and 1,839 were diagnosed with ovarian cancer), with a further replication in an additional sample of 2,646 BRCA1 carriers. We identified a novel breast cancer risk modifier locus at 1q32 for BRCA1 carriers (rs2290854, P = 2.7×10-8, HR = 1.14, 95% CI: 1.09-1.20). In addition, we identified two novel ovarian cancer risk modifier loci: 17q21.31 (rs17631303, P = 1.4×10-8, HR = 1.27, 95% CI: 1.17-1.38) and 4q32.3 (rs4691139, P = 3.4×10-8, HR = 1.20, 95% CI: 1.17-1.38). The 4q32.3 locus was not associated with ovarian cancer risk in the general population or BRCA2 carriers, suggesting a BRCA1-specific associat

An original phylogenetic approach identified mitochondrial haplogroup T1a1 as inversely associated with breast cancer risk in BRCA2 mutation carriers

Introduction: Individuals carrying pathogenic mutations in the BRCA1 and BRCA2 genes have a high lifetime risk of breast cancer. BRCA1 and BRCA2 are involved in DNA double-strand break repair, DNA alterations that can be caused by exposure to reactive oxygen species, a main source of which are mitochondria. Mitochondrial genome variations affect electron transport chain efficiency and reactive oxygen species production. Individuals with different mitochondrial haplogroups differ in their metabolism and sensitivity to oxidative stress. Variability in mitochondrial genetic background can alter reactive oxygen species production, leading to cancer risk. In the present study, we tested the hypothesis that mitochondrial haplogroups modify breast cancer risk in BRCA1/2 mutation carriers. Methods: We genotyped 22,214 (11,421 affected, 10,793 unaffected) mutation carriers belonging to the Consortium of Investigators of Modifiers of BRCA1/2 for 129 mitochondrial polymorphisms using the iCOGS array. Haplogroup inference and association detection were performed using a phylogenetic approach. ALTree was applied to explore the reference mitochondrial evolutionary tree and detect subclades enriched in affected or unaffected individuals. Results: We discovered that subclade T1a1 was depleted in affected BRCA2 mutation carriers compared with the rest of clade T (hazard ratio (HR) = 0.55; 95% confidence interval (CI), 0.34 to 0.88; P = 0.01). Compared with the most frequent haplogroup in the general population (that is, H and T clades), the T1a1 haplogroup has a HR of 0.62 (95% CI, 0.40 to 0.95; P = 0.03). We also identified three potential susceptibility loci, including G13708A/rs28359178, which has demonstrated an inverse association with familial breast cancer risk. Conclusions: This study illustrates how original approaches such as the phylogeny-based method we used can empower classical molecular epidemiological studies aimed at identifying association or risk modification effects.Peer reviewe

Novel Reporter Alleles of GSK-3 alpha and GSK-3 beta

Glycogen Synthase Kinase 3 (GSK-3) is a key player in development, physiology and disease. Because of this, GSK-3 inhibitors are increasingly being explored for a variety of applications. In addition most analyses focus on GSK-3β and overlook the closely related protein GSK-3α. Here, we describe novel GSK-3α and GSK-3β mouse alleles that allow us to visualise expression of their respective mRNAs by tracking β-galactosidase activity. We used these new lacZ alleles to compare expression in the palate and cranial sutures and found that there was indeed differential expression. Furthermore, both are loss of function alleles and can be used to generate homozygous mutant mice; in addition, excision of the lacZ cassette from GSK-3α creates a Cre-dependent tissue-specific knockout. As expected, GSK3α mutants were viable, while GSK3β mutants died after birth with a complete cleft palate. We also assessed the GSK-3α mutants for cranial and sternal phenotypes and found that they were essentially normal. Finally, we observed gestational lethality in compound GSK-3β(-/-); GSK3α(+/-) mutants, suggesting that GSK-3 dosage is critical during embryonic development

New directions in craniofacial morphogenesis

AbstractThe vertebrate head is an extremely complicated structure: development of the head requires tissue–tissue interactions between derivates of all the germ layers and coordinated morphogenetic movements in three dimensions. In this review, we highlight a number of recent embryological studies, using chicken, frog, zebrafish and mouse, which have identified crucial signaling centers in the embryonic face. These studies demonstrate how small variations in growth factor signaling can lead to a diversity of phenotypic outcomes. We also discuss novel genetic studies, in human, mouse and zebrafish, which describe cell biological mechanisms fundamental to the growth and morphogenesis of the craniofacial skeleton. Together, these findings underscore the complex interactions leading to species-specific morphology. These and future studies will improve our understanding of the genetic and environmental influences underlying human craniofacial anomalies

Targeted mutations in GSK-3α and GSK-3β.

<p>A. Top row: schematic of mouse GSK-3α locus. Middle row: region containing exons 1–3 are depicted showing cartoon of GSK-3α^L allele. Bottom row: schematic depicting genomic locus after crossing with “FLPeR” mice, deleting the FRT flanked region between exon 1 and 2. Maps adapted from <a href="http://www.knockoutmouse.org/martsearch/project/27450" target="_blank">http://www.knockoutmouse.org/martsearch/project/27450</a>. Not to scale. B. Top row: schematic of mouse GSK-3β locus. Second row: cartoon of lacZ/neo cassette inserted into exon 2. Not to scale. Abbreviations: FRT = flip recombinase target; En2 SA = En2 splice acceptor; T2A = T2A oligopeptide for ribosomal skipping; pA = polyadenylation; neo = neomycin resistance gene C. Genotyping of GSK-3α^LacZ allele from heterozygous (+/L), wildtype (+/+) and mutant (L/L) animals. PCR products: wildtype band (227 bp), mutant band (182 bp). D. Genotyping of GSK-3α^Flox allele from wildtype (+/+), homozygous (fl/fl) and heterozygous (+/fl) animals. PCR products: wildtype (227 bp), mutant bands (182 bp with two accessory bands at ∼400 bp and ∼500 bp E. Genotyping of GSK-3β^LacZ allele from wildtype (+/+), homozygous (L/L) and heterozygous (+/L) animals. PCR products: wildtype band (263 bp), mutant band (500 bp). F. Western blot analysis of e17.5 kidneys. Genotypes are indicated below. Note expression of both GSK-3α and GSK-3β proteins in wildtype (+/+) animals. Heterozygous (+/L) animals have decreased expression of GSK-3α while homozygous mutants (L/L) samples express no GSK-3α protein. HSP90 was used as a loading control. G. Western blot analysis of adult brains from GSK-3α^fl/fl mice show normal expression of GSK-3α and GSK-3β, compared to heterozygous GSK-3α^+/fl mice, confirming return of protein expression after intercross with FLPeR mice. HSP90 serves as a loading control. H. Western blot analysis of e13.5 brains show loss of GSK-3β protein in GSK-3β mutant (L/L) animals, compared to wildtype (+/+). HSP90 serves as a loading control.</p

GSK-3α and GSK-3β <i>lacZ</i> reporter expression in the postnatal skull vault was visualized by X-gal staining (blue). Scale bar = 1 mm.

<p>A–B. Dorsal view of GSK-3α and GSK-3β reporter expression in postnatal sutures (P6 and P9, respectively). Robust GSK-3α reporter expression is seen in the sutures compared to minimal GSK-3β reporter activity. C–D. Nasal suture region. Both GSK-3α and β expression is seen in the frontonasal (FNS) and frontomaxillary (FMS) suture. Expression of the GSK-3α reporter is also found in the internasal (INS) and premaxillary-maxillary (PMS) suture (C). GSK-3β is also expressed in the premaxillary-maxillary suture but only in the anterior internasal (INS) suture. E–F. Cranial suture region. GSK-3α is expressed in the interfrontal (IFS), coronal (CS) and sagittal (SS) sutures (E); but, GSK-3β is only expressed in the sagittal suture (F).</p