Biophysical ordering transitions underlie genome 3D re-organization during cricket spermiogenesis.

Spermiogenesis is a radical process of differentiation whereby sperm cells acquire a compact and specialized morphology to cope with the constraints of sexual reproduction while preserving their main cargo, an intact copy of the paternal genome. In animals, this often involves the replacement of most histones by sperm-specific nuclear basic proteins (SNBPs). Yet, how the SNBP-structured genome achieves compaction and accommodates shaping remain largely unknown. Here, we exploit confocal, electron and super-resolution microscopy, coupled with polymer modeling to identify the higher-order architecture of sperm chromatin in the needle-shaped nucleus of the emerging model cricket Gryllus bimaculatus. Accompanying spermatid differentiation, the SNBP-based genome is strikingly reorganized as ~25nm-thick fibers orderly coiled along the elongated nucleus axis. This chromatin spool is further found to achieve large-scale helical twisting in the final stages of spermiogenesis, favoring its ultracompaction. We reveal that these dramatic transitions may be recapitulated by a surprisingly simple biophysical principle based on a nucleated rigidification of chromatin linked to the histone-to-SNBP transition within a confined nuclear space. Our work highlights a unique, liquid crystal-like mode of higher-order genome organization in ultracompact cricket sperm, and establishes a multidisciplinary methodological framework to explore the diversity of non-canonical modes of DNA organization.

The neurodevelopmental gene MSANTD2 belongs to a gene family formed by recurrent molecular domestication of Harbinger transposons at the base of vertebrates.

The formation of new genes is a major source of organism evolutionary innovation. Beyond their mutational effects, transposable elements can be co-opted by host genomes to form different types of sequences including novel genes, through a mechanism named molecular domestication.We report the formation of four genes through molecular domestication of Harbinger transposons, three in a common ancestor of jawed vertebrates about 500 million years ago and one in sarcopterygians approx. 430 million years ago. Additionally, one processed pseudogene arose approx. 60 million years ago in simians. In zebrafish, Harbinger-derived genes are expressed during early development but also in adult tissues, and predominantly co-expressed in male brain. In human, expression was detected in multiple organs, with major expression in the brain particularly during fetal development. We used CRISPR/Cas9 with direct gene knock-out in the F0 generation and the morpholino antisense oligonucleotide knock-down technique to study in zebrafish the function of one of these genes called MSANTD2, which has been suggested to be associated to neuro-developmental diseases such as autism spectrum disorders and schizophrenia in human. MSANTD2 inactivation led to developmental delays including tail and nervous system malformation at one day post fertilization. Affected embryos showed dead cell accumulation, major anatomical defects characterized by impaired brain ventricle formation and alterations in expression of some characteristic genes involved in vertebrate nervous system development. Hence, the characterization of MSANTD2 and other Harbinger-derived genes might contribute to a better understanding of the genetic innovations having driven the early evolution of the vertebrate nervous system.

Adherence to Adalimumab Was Not Improved by a Reminder-Based Intervention with an Electronic Needle Container.

BACKGROUND: Adherence to adalimumab in inflammatory bowel disease (IBD) patients is reported to be below par. Non-adherence may result in loss-of-response and increased hospitalization. We analyzed the effect of an electronic needle container (ENC) on adherence to adalimumab. METHODS: In this multicenter, 12-months observational study, we included adalimumab treated IBD patients. All patients were invited to receive an ENC. Patients who declined or did not complete the registration for an ENC served as controls. Primary endpoint was whether an ENC increased adherence, calculated from pharmacy refills as proportion of days covered (PDC). Secondary endpoints were clinical outcomes, including loss-of-response, identification of predictors of adherence and correlation between different modalities for measuring adherence. Loss-of-response was defined as a disease flare, dose-escalation or IBD-related hospitalization or surgery. RESULTS: The pharmacies' records identified 198 eligible patients, of whom 32 were excluded. The ENC was supplied to 69 patients, the remaining 97 patient formed the control group. Median baseline PDC (98.4% vs. 96.1%, p = 0.047) and the proportion of adherent (PDC ≥ 86%) patients (87.0% vs. 74.2%, p = 0.045) was higher for the ENC group. The ENC did not improve the adherence of patients during follow-up (odds ratio 1.26, 95% CI 0.55-2.86). During follow-up, five (7.2%) patients in the ENC group and 13 (13.4%) in the control group discontinued adalimumab (log-rank p = 0.22). Loss-of-response occurred in 12 (17.4%) and 14 (14.4%) patients, respectively (log-rank p = 0.66). CONCLUSIONS: Our results show no beneficial effect of a reminder-based intervention on adherence or treatment outcomes.

Decision aids can decrease decisional conflict in patients with hip or knee osteoarthritis: Randomized controlled trial.

BACKGROUND: The interest in shared decision making has increased considerably over the last couple of decades. Decision aids (DAs) can help in shared decision making. Especially when there is more than one reasonable option and outcomes between treatments are comparable. AIM: To investigate if the use of DAs decreases decisional conflict in patients when choosing treatment for knee or hip osteoarthritis (OA). METHODS: In this multi-center unblinded randomized controlled trial of patients with knee or hip OA were included from four secondary and tertiary referral centers. One-hundred-thirty-one patients who consulted an orthopedic surgeon for the first time with knee or hip OA were included between December 2014 and January 2016. After the first consultation, patients were randomly assigned by a computer to the control group which was treated according to standard care, or to the intervention group which was treated with standard care and provided with a DA. After the first consultation, patients were asked to complete questionnaires about decisional conflict (DCS), satisfaction, anxiety (PASS-20), gained knowledge, stage of decision making and preferred treatment. Follow-up was carried out after 26 wk and evaluated decisional conflict, satisfaction, anxiety, health outcomes (HOOS/KOOS), quality of life (EQ5D) and chosen treatment. RESULTS: After the first consultation, patients in the intervention group (mean DCS: 25 out of 100, SD: 13) had significantly (P value: 0.00) less decisional conflict compared to patients in the control group (mean DCS: 39 out of 100, SD 11). The mean satisfaction score for the given information (7.6 out of 10, SD: 1.8 vs 8.6 out of 10, SD: 1.1) (P value: 0.00), mean satisfaction score with the physician (8.3 out of 10, SD: 1.7 vs 8.9 out of 10, SD: 0.9) (P value: 0.01) and the mean knowledge score (3.3 out of 4, SD: 0.9 vs 3.7 out of, SD: 0.6) (P value: 0.01) were all significantly higher in the intervention group. At 26-wk follow-up, only 75 of 131 patients (57%) were available for analysis. This sample is too small for meaningful analysis. CONCLUSION: Providing patients with an additional DA may have a positive effect on decisional conflict after the first consultation. Due to loss to follow-up we are unsure if this effect remains over time.

Interplay of RFX transcription factors 1, 2 and 3 in motile ciliogenesis.

Cilia assembly is under strict transcriptional control during animal development. In vertebrates, a hierarchy of transcription factors (TFs) are involved in controlling the specification, differentiation and function of multiciliated epithelia. RFX TFs play key functions in the control of ciliogenesis in animals. Whereas only one RFX factor regulates ciliogenesis in C. elegans, several distinct RFX factors have been implicated in this process in vertebrates. However, a clear understanding of the specific and redundant functions of different RFX factors in ciliated cells remains lacking. Using RNA-seq and ChIP-seq approaches we identified genes regulated directly and indirectly by RFX1, RFX2 and RFX3 in mouse ependymal cells. We show that these three TFs have both redundant and specific functions in ependymal cells. Whereas RFX1, RFX2 and RFX3 occupy many shared genomic loci, only RFX2 and RFX3 play a prominent and redundant function in the control of motile ciliogenesis in mice. Our results provide a valuable list of candidate ciliary genes. They also reveal stunning differences between compensatory processes operating in vivo and ex vivo.

Wound complications after total hip arthroplasty: a prospective, randomised controlled trial comparing staples with sutures.

OBJECTIVE: Does the use of staples or sutures for wound closure have a lower surgical site infection rate in patients receiving primary total hip arthroplasty (THA)? DESIGN: Prospective, randomised controlled multicentre trial. METHODS: 535 patients undergoing THA were included and randomised into 2 groups: 268 wounds were closed with staples, and 267 with sutures. Primary outcome was surgical site infection (SSI). Secondary outcomes were prosthetic joint infection (PJI), other wound complications (dehiscence, necrosis and prolonged drainage) and duration of admittance. Follow-up occurred at 2, 6, and 12 weeks, and at 1 year. RESULTS: There were no significant demographic differences between the 2 groups. SSI occurred more frequently when wounds were closed with staples (4% compared to 1% with sutures; OR 2.8; CI, 0.885-0.952; p = 0.057). SSI was treated with oral antibiotics. The staples group showed significantly more wound complications (17% compared to 5%; OR 3.943, CI 2.073-7.498; p = 0.000). Wound discharge was significantly prolonged in the staples group (n = 40, compared to n = 12 in the sutures group; OR 3.728; CI, 1.909-7.281; p = 0.000). There was no significant difference in PJI (p = 0.364). CONCLUSIONS: In this large RCT comparing staples with sutures after THA, the use of staples is associated with a nearly 3 times greater risk of SSI (OR 2.8; p = 0.057). Staples significantly prolong wound discharge. The use of sutures for wound closure after THA is advised. Trial registration: Staples Or Sutures trial (S.O.S. trial) http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=3946 , NTR3946.

Altered GLI3 and FGF8 signaling underlies acrocallosal syndrome phenotypes in Kif7 depleted mice.

Acrocallosal syndrome (ACLS) is a rare genetic disorder characterized by agenesis or hypoplasia of corpus callosum (CC), polydactyly, craniofacial dysmorphism and severe intellectual deficiency. We previously identified KIF7, a key ciliary component of the Sonic hedgehog (SHH) pathway, as being a causative gene for this syndrome, thus including ACLS in the group of ciliopathies. In both humans and mice, KIF7 depletion leads to abnormal GLI3 processing and over-activation of SHH target genes. To understand the pathological mechanisms involved in CC defects in this syndrome, we took advantage of a previously described Kif7-/- mouse model to demonstrate that in addition to polydactyly and neural tube closure defects, these mice present CC agenesis with characteristic Probst bundles, thus recapitulating major ACLS features. We show that CC agenesis in these mice is associated with specific patterning defects of the cortical septum boundary leading to altered distribution of guidepost cells required to guide the callosal axons through the midline. Furthermore, by crossing Kif7-/- mice with Gli3Δ699 mice exclusively producing the repressive isoform of GLI3 (GLI3R), we demonstrate that decreased GLI3R signaling is fully responsible for the ACLS features in these mice, as all phenotypes are rescued by increasing GLI3R activity. Moreover, we show that increased FGF8 signaling is responsible in part for CC defects associated to KIF7 depletion, as modulating FGF8 signaling rescued CC formation anteriorly in Kif7-/- mice. Taken together our data demonstrate that ACLS features rely on defective GLI3R and FGF8 signaling.

Perforator-Based Interposition Flaps Perform Better Than Full-Thickness Grafts for the Release of Burn Scar Contractures: A Multicenter Randomized Controlled Trial.

BACKGROUND: Burn scar contractures remain a significant problem for the severely burned patient. Reconstructive surgery is often indicated to improve function and quality of life. Skin grafts (preferably full-thickness grafts) are frequently used to cover the defect that remains after scar release. Local flaps are also used for this purpose and provide healthy skin subcutaneous tissue. The vascularization and versatility of local flaps can be further improved by enclosing a perforator at the base of the flap. Until now, no randomized controlled trial has been performed to determine which technique has the best effectiveness in burn scar contracture releasing procedures. METHODS: A multicenter randomized controlled trial was performed to compare the effectiveness of perforator-based interposition flaps to full-thickness skin grafts for the treatment of burn scar contractures. The primary outcome parameter was change in the surface area of the flap or full-thickness skin graft. Secondary outcome parameters were width, elasticity, color, Patient and Observer Scar Assessment Scale score, and range of motion. Measurements were performed after 3 and 12 months. RESULTS: The mean surface area between flaps (n = 16) and full-thickness skin grafts (n = 14) differed statistically significantly at 3 months (123 percent versus 87 percent; p < 0.001) and 12 months (142 percent versus 92 percent; p < 0.001). In terms of the secondary outcome parameters (specifically, the Patient and Observer Scar Assessment Scale observer score and color), interposition flaps showed superior results compared with full-thickness skin grafts. CONCLUSION: Perforator-based interposition flaps result in a more effective scar contracture release than full-thickness skin grafts and should therefore be preferred over full-thickness skin grafts when possible. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, I.

mTOR inactivation in myocardium from infant mice rapidly leads to dilated cardiomyopathy due to translation defects and p53/JNK-mediated apoptosis.

Mechanistic target of rapamycin (mTOR) is a central regulator of cell growth, proliferation, survival and metabolism, as part of mTOR complex 1 (mTORC1) and mTORC2. While partial inhibition of mTORC1 using rapamycin was shown to be cardioprotective, genetic studies in mouse models revealed that mTOR is essential for embryonic heart development and cardiac function in adults. However, the physiological role of mTOR during postnatal cardiac maturation is not fully elucidated. We have therefore generated a mouse model in which cardiac mTOR was inactivated at an early postnatal stage. Mutant mTORcmKO mice rapidly developed a dilated cardiomyopathy associated with cardiomyocyte growth defects, apoptosis and fibrosis, and died during their third week. Here, we show that reduced cardiomyocyte growth results from impaired protein translation efficiency through both 4E-BP1-dependent and -independent mechanisms. In addition, infant mTORcmKO hearts displayed markedly increased apoptosis linked to stretch-induced ANKRD1 (Ankyrin repeat-domain containing protein 1) up-regulation, JNK kinase activation and p53 accumulation. Pharmacological inhibition of p53 with pifithrin-α attenuated caspase-3 activation. Cardiomyocyte death did not result from activation of the MST1/Hippo pro-apoptotic pathway as reported in adult rictor/mTORC2 KO hearts. As well, mTORcmKO hearts showed a strong downregulation of myoglobin content, thereby leading to a hypoxic environment. Nevertheless, they lacked a HIF1α-mediated adaptive response, as mTOR is required for hypoxia-induced HIF-1α activation. Altogether, our results demonstrate that mTOR is critically required for cardiomyocyte growth, viability and oxygen supply in early postnatal myocardium and provide insight into the molecular mechanisms involved in apoptosis of mTOR-depleted cardiomyocytes.

Transepidermal water loss measured with the Tewameter TM300 in burn scars.

Transepidermal water loss (TEWL) is a physiological characteristic to measure the efficiency of the skin barrier. The aim was to investigate the reliability of the Tewameter TM300 for the assessment of TEWL (g/m2/h) in burn scars. Also the relation between TEWL scar values and scar quality parameters was investigated. Three different study areas (scar, healthy adjacent and contralateral skin) were assessed in 55 adult patients. The intra- and inter-observer reliability were tested using the intra-class correlation coefficient (ICC) and the standard error of measurement (SEM). The inter-observer reliability for the three areas was excellent with ICC values between 0.85 and 0.94. SEM values were between 1.76 and 3.97g/m2/h. Bland-Altman plots showed relatively wide LoA values for scar and healthy skin. Mean TEWL scar values were significantly higher than healthy skin (p<0.001). Significant correlations were found between TEWL hypertrophic scar values and erythema (r=0.60, p=0.001) and a negative correlation for weeks after burn (r=-0.61, p=0.001). TEWL values were significantly different between 3 and 6 months and 3 and 12 months old scars (respectively p=0.021 and p=0.002). To evaluate the skin barrier function over time as a measure for scar maturation, Tewameter TM300 measurements have to be performed according to strict and standardized protocols.

RFX2 Is a Major Transcriptional Regulator of Spermiogenesis.

Spermatogenesis consists broadly of three phases: proliferation of diploid germ cells, meiosis, and finally extensive differentiation of the haploid cells into effective delivery vehicles for the paternal genome. Despite detailed characterization of many haploid developmental steps leading to sperm, only fragmentary information exists on the control of gene expression underlying these processes. Here we report that the RFX2 transcription factor is a master regulator of genes required for the haploid phase. A targeted mutation of Rfx2 was created in mice. Rfx2-/- mice are perfectly viable but show complete male sterility. Spermatogenesis appears to progress unperturbed through meiosis. However, haploid cells undergo a complete arrest in spermatid development just prior to spermatid elongation. Arrested cells show altered Golgi apparatus organization, leading to a deficit in the generation of a spreading acrosomal cap from proacrosomal vesicles. Arrested cells ultimately merge to form giant multinucleated cells released to the epididymis. Spermatids also completely fail to form the flagellar axoneme. RNA-Seq analysis and ChIP-Seq analysis identified 139 genes directly controlled by RFX2 during spermiogenesis. Gene ontology analysis revealed that genes required for cilium function are specifically enriched in down- and upregulated genes showing that RFX2 allows precise temporal expression of ciliary genes. Several genes required for cell adhesion and cytoskeleton remodeling are also downregulated. Comparison of RFX2-regulated genes with those controlled by other major transcriptional regulators of spermiogenesis showed that each controls independent gene sets. Altogether, these observations show that RFX2 plays a major and specific function in spermiogenesis.

The role of primary cilia in corpus callosum formation is mediated by production of the Gli3 repressor.

Agenesis of the corpus callosum (AgCC) is a frequent brain disorder found in over 80 human congenital syndromes including ciliopathies. Here, we report a severe AgCC in Ftm/Rpgrip1l knockout mouse, which provides a valuable model for Meckel-Grüber syndrome. Rpgrip1l encodes a protein of the ciliary transition zone, which is essential for ciliogenesis in several cell types in mouse including neuroepithelial cells in the developing forebrain. We show that AgCC in Rpgrip1l(-/-) mouse is associated with a disturbed location of guidepost cells in the dorsomedial telencephalon. This mislocalization results from early patterning defects and abnormal cortico-septal boundary (CSB) formation in the medial telencephalon. We demonstrate that all these defects primarily result from altered GLI3 processing. Indeed, AgCC, together with patterning defects and mispositioning of guidepost cells, is rescued by overexpressing in Rpgrip1l(-/-) embryos, the short repressor form of the GLI3 transcription factor (GLI3R), provided by the Gli3(Δ699) allele. Furthermore, Gli3(Δ699) also rescues AgCC in Rfx3(-/-) embryos deficient for the ciliogenic RFX3 transcription factor that regulates the expression of several ciliary genes. These data demonstrate that GLI3 processing is a major outcome of primary cilia function in dorsal telencephalon morphogenesis. Rescuing CC formation in two independent ciliary mutants by GLI3(Δ699) highlights the crucial role of primary cilia in maintaining the proper level of GLI3R required for morphogenesis of the CC.

Underdiagnosis of foodborne hepatitis A, The Netherlands, 2008-2010(1.).

Outbreaks of foodborne hepatitis A are rarely recognized as such. Detection of these infections is challenging because of the infection's long incubation period and patients' recall bias. Nevertheless, the complex food market might lead to reemergence of hepatitis A virus outside of disease-endemic areas. To assess the role of food as a source of infection, we combined routine surveillance with real-time strain sequencing in the Netherlands during 2008-2010. Virus RNA from serum of 248 (59%) of 421 reported case-patients could be sequenced. Without typing, foodborne transmission was suspected for only 4% of reported case-patients. With typing, foodborne transmission increased to being the most probable source of infection for 16%. We recommend routine implementation of an enhanced surveillance system that includes prompt forwarding and typing of hepatitis A virus RNA isolated from serum, standard use of questionnaires, data sharing, and centralized interpretation of data.

The coiled-coil domain containing protein CCDC151 is required for the function of IFT-dependent motile cilia in animals.

Cilia are evolutionarily conserved organelles endowed with essential physiological and developmental functions. In humans, disruption of cilia motility or signaling leads to complex pleiotropic genetic disorders called ciliopathies. Cilia motility requires the assembly of multi-subunit motile components such as dynein arms, but mechanisms underlying their assembly pathway and transport into the axoneme are still largely unknown. We identified a previously uncharacterized coiled-coil domain containing protein CCDC151, which is evolutionarily conserved in motile ciliated species and shares ancient features with the outer dynein arm-docking complex 2 of Chlamydomonas. In Drosophila, we show that CG14127/CCDC151 is associated with motile intraflagellar transport (IFT)-dependent cilia and required for geotaxis behavior of adult flies. In zebrafish, Ccdc151 is expressed in tissues with motile cilia, and morpholino-induced depletion of Ccdc151 leads to left-right asymmetry defects and kidney cysts. We demonstrate that Ccdc151 is required for proper motile function of cilia in the Kupffer's vesicle and in the pronephros by controlling dynein arm assembly, showing that Ccdc151 is a novel player in the control of IFT-dependent dynein arm assembly in animals. However, we observed that CCDC151 is also implicated in other cellular functions in vertebrates. In zebrafish, ccdc151 is involved in proper orientation of cell divisions in the pronephros and genetically interacts with prickle1 in this process. Furthermore, knockdown experiments in mammalian cells demonstrate that CCDC151 is implicated in the regulation of primary cilium length. Hence, CCDC151 is required for motile cilia function in animals but has acquired additional non-motile functions in vertebrates.

Detection of influenza A virus homo- and heterosubtype-specific memory B-cells using a novel protein microarray-based analysis tool.

The emergence of the A(H1N1) 2009 pandemic influenza virus was initially seen as a major world-wide health concern since a low degree of immunity to this virus strain was anticipated. However, age-specific infection attack rates and age-specific differences in seroresponse indicate that pre-existing immunity may have played a significant role in protection especially in older age groups. This study describes the use of a protein microarray as a multiplex analysis tool for detection of influenza virus H1 strain-specific memory B-cells before and after infection with A(H1N1)pdm09. The discrimination was based on detection of specific antibodies in culture supernatants from polyclonally stimulated B-cells against recombinant influenza virus HA1 proteins representing influenza virus subtypes H1 through H9. The protein microarray proved sensitive and specific for antibody detection in culture supernatants of B-cells, and with the potential to deduce a person's history of infection with particular influenza virus variants, including A(H1N1)pdm09. Blood samples obtained from different age groups prior to the pandemic in 2009 partly showed the presence of B-cells producing antibodies binding to the closely related A(H1N1) 1918 pandemic influenza virus, and of which the magnitude increased with age. These cross-reactive antibodies were produced by single memory B-cells present in these donors, and either bind to epitopes on HA1 which are shared within different H1 strains (homosubtypic response) or shared between different subtypes (heterosubtypic response).

CKIP-1 regulates mammalian and zebrafish myoblast fusion.

Multinucleated muscle fibres arise by fusion of precursor cells called myoblasts. We previously showed that CKIP-1 ectopic expression in C2C12 myoblasts increased cell fusion. In this work, we report that CKIP-1 depletion drastically impairs C2C12 myoblast fusion in vitro and in vivo during zebrafish muscle development. Within developing fast-twich myotome, Ckip-1 localises at the periphery of fast precursor cells, closed to the plasma membrane. Unlike wild-type myoblasts that form spatially arrayed multinucleated fast myofibres, Ckip-1-deficient myoblasts show a drastic reduction in fusion capacity. A search for CKIP-1 binding partners identified the ARPC1 subunit of Arp2/3 actin nucleation complex essential for myoblast fusion. We demonstrate that CKIP-1, through binding to plasma membrane phosphoinositides via its PH domain, regulates cell morphology and lamellipodia formation by recruiting the Arp2/3 complex at the plasma membrane. These results establish CKIP-1 as a regulator of cortical actin that recruits the Arp2/3 complex at the plasma membrane essential for muscle precursor elongation and fusion.

Multicenter cohort association study of SLC2A1 single nucleotide polymorphisms and age-related macular degeneration.

PURPOSE: Age-related macular degeneration (AMD) is a major cause of blindness in older adults and has a genetically complex background. This study examines the potential association between single nucleotide polymorphisms (SNPs) in the glucose transporter 1 (SLC2A1) gene and AMD. SLC2A1 regulates the bioavailability of glucose in the retinal pigment epithelium (RPE), which might influence oxidative stress-mediated AMD pathology. METHODS: Twenty-two SNPs spanning the SLC2A1 gene were genotyped in 375 cases and 199 controls from an initial discovery cohort (the Amsterdam-Rotterdam-Netherlands study). Replication testing was performed in The Rotterdam Study (the Netherlands) and study populations from Würzburg (Germany), the Age Related Eye Disease Study (AREDS; United States), Columbia University (United States), and Iowa University (United States). Subsequently, a meta-analysis of SNP association was performed. RESULTS: In the discovery cohort, significant genotypic association between three SNPs (rs3754219, rs4660687, and rs841853) and AMD was found. Replication in five large independent (Caucasian) cohorts (4,860 cases and 4,004 controls) did not yield consistent association results. The genotype frequencies for these SNPs were significantly different for the controls and/or cases among the six individual populations. Meta-analysis revealed significant heterogeneity of effect between the studies. CONCLUSIONS: No overall association between SLC2A1 SNPs and AMD was demonstrated. Since the genotype frequencies for the three SLC2A1 SNPs were significantly different for the controls and/or cases between the six cohorts, this study corroborates previous evidence that population dependent genetic risk heterogeneity in AMD exists.

Complement factor H genetic variant and age-related macular degeneration: effect size, modifiers and relationship to disease subtype.

BACKGROUND: Variation in the complement factor H gene (CFH) is associated with risk of late age-related macular degeneration (AMD). Previous studies have been case-control studies in populations of European ancestry with little differentiation in AMD subtype, and insufficient power to confirm or refute effect modification by smoking. METHODS: To precisely quantify the association of the single nucleotide polymorphism (SNP rs1061170, 'Y402H') with risk of AMD among studies with differing study designs, participant ancestry and AMD grade and to investigate effect modification by smoking, we report two unpublished genetic association studies (n = 2759) combined with data from 24 published studies (26 studies, 26,494 individuals, including 14,174 cases of AMD) of European ancestry, 10 of which provided individual-level data used to test gene-smoking interaction; and 16 published studies from non-European ancestry. RESULTS: In individuals of European ancestry, there was a significant association between Y402H and late-AMD with a per-allele odds ratio (OR) of 2.27 [95% confidence interval (CI) 2.10-2.45; P = 1.1 x 10(-161)]. There was no evidence of effect modification by smoking (P = 0.75). The frequency of Y402H varied by ancestral origin and the association with AMD in non-Europeans was less clear, limited by paucity of studies. CONCLUSION: The Y402H variant confers a 2-fold higher risk of late-AMD per copy in individuals of European descent. This was stable to stratification by study design and AMD classification and not modified by smoking. The lack of association in non-Europeans requires further verification. These findings are of direct relevance for disease prediction. New research is needed to ascertain if differences in circulating levels, expression or activity of factor H protein explain the genetic association.

The ERCC6 gene and age-related macular degeneration.

BACKGROUND: Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the developed countries and is caused by both environmental and genetic factors. A recent study (Tuo et al., PNAS) reported an association between AMD and a single nucleotide polymorphism (SNP) (rs3793784) in the ERCC6 (NM_000124) gene. The risk allele also increased ERCC6 expression. ERCC6 is involved in DNA repair and mutations in ERCC6 cause Cockayne syndrome (CS). Amongst others, photosensitivity and pigmentary retinopathy are hallmarks of CS. METHODOLOGY/PRINCIPAL FINDINGS: Separate and combined data from three large AMD case-control studies and a prospective population-based study (The Rotterdam Study) were used to analyse the genetic association between ERCC6 and AMD (2682 AMD cases and 3152 controls). We also measured ERCC6 mRNA levels in retinal pigment epithelium (RPE) cells of healthy and early AMD affected human donor eyes. Rs3793784 conferred a small increase in risk for late AMD in the Dutch population (The Rotterdam and AMRO-NL study), but this was not replicated in two non-European studies (AREDS, Columbia University). In addition, the AMRO-NL study revealed no significant association for 9 other variants spanning ERCC6. Finally, we determined that ERCC6 expression in the human RPE did not depend on rs3793784 genotype, but, interestingly, on AMD status: Early AMD-affected donor eyes had a 50% lower ERCC6 expression than healthy donor eyes (P = 0.018). CONCLUSIONS/SIGNIFICANCE: Our meta-analysis of four Caucasian cohorts does not replicate the reported association between SNPs in ERCC6 and AMD. Nevertheless, our findings on ERCC6 expression in the RPE suggest that ERCC6 may be functionally involved in AMD. Combining our data with those of the literature, we hypothesize that the AMD-related reduced transcriptional activity of ERCC6 may be caused by diverse, small and heterogeneous genetic and/or environmental determinants.

DHPR alpha1S subunit controls skeletal muscle mass and morphogenesis.

The alpha1S subunit has a dual function in skeletal muscle: it forms the L-type Ca(2+) channel in T-tubules and is the voltage sensor of excitation-contraction coupling at the level of triads. It has been proposed that L-type Ca(2+) channels might also be voltage-gated sensors linked to transcriptional activity controlling differentiation. By using the U7-exon skipping strategy, we have achieved long-lasting downregulation of alpha1S in adult skeletal muscle. Treated muscles underwent massive atrophy while still displaying significant amounts of alpha1S in the tubular system and being not paralysed. This atrophy implicated the autophagy pathway, which was triggered by neuronal nitric oxide synthase redistribution, activation of FoxO3A, upregulation of autophagy-related genes and autophagosome formation. Subcellular investigations showed that this atrophy was correlated with the disappearance of a minor fraction of alpha1S located throughout the sarcolemma. Our results reveal for the first time that this sarcolemmal fraction could have a role in a signalling pathway determining muscle anabolic or catabolic state and might act as a molecular sensor of muscle activity.