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Functional near-infrared spectroscopy (fNIRS) long channels signals are contaminated by motion artifacts and extra-cerebral tissues activity during motor production. In this study, we aimed at quantifying these limitations using an fNIRS continuous-wave system during whole-body movement (i.e., cycling task). Using motion-capture recordings, physiological monitoring and short channels, our results showed a high stability of the headset during whole-body movements production and demonstrated the ability of short channels to capture physiological extra-cerebral activity., {"references":["https://doi.org/10.1016/j.neuroimage.2020.117597","https://doi.org/10.1016/j.neuroimage.2013.05.004"]}

Even with the recent works on fNIRS robustness and reproducibility, this technique still lacks of standardised methodological precautions and evidence-based recommendations to guide whole-body movement protocol building. We present a procedure that aimed at verifying the stability of the fNIRS headset during whole-body movements, to properly track the anatomical locations of the recorded signals. In addition, we showed that averaging at least 10 trials for a block-design procedure is necessary to improve fNIRS reproducibility and to obtain a robust haemodynamic response. Finally, we demonstrated that the test–retest reliability of fNIRS signals is high, even in whole-body movement motor paradigms., {"references":["] Guérin, S. M. R., Vincent, M. A., Karageorghis, C. I., & Delevoye-Turrell, Y. N. (2021). Effects of motor tempo on frontal brain activity: An fNIRS study. NeuroImage, 230, Article 117597. https://doi.org/10.1016/j.neuroimage.2020.117597"]}

Adipose tissue is a key regulator of whole-body metabolic fitness because of its role in controlling insulin sensitivity. Obesity is associated with hypertrophic adipocytes with impaired glucose absorption; a phenomenon existing in the ultra-rare monogenic disorder Alström syndrome consisting of severe insulin resistance. Inactivation of ALMS1 directly inhibits insulin-mediated glucose absorption in the white adipose tissue and induces severe insulin resistance, which leads to type 2 diabetes, accelerated non-alcoholic liver disease and fibrosis. These phenotypes were reversed by specific adipocyte-ALMS1 reactivation in vivo. Subsequently, ALMS1 was found to bind to PKC alpha in the adipocyte and upon insulin signaling PKC alpha is released from ALMS1. Alpha helices in the kinase domain of PKC alpha were therefore screened to identify a peptide sequence that interfered with the ALMS1-PKC alpha protein interaction. When incubated with cultured human adipocytes, the stapled peptide termed PATAS, for Peptide derived of PKC Alpha Targeting AlmS, triggered insulin-independent glucose absorption, de novo lipogenesis and cellular glucose utilization. In vivo, PATAS reduced whole-body insulin resistance, improved glucose intolerance, fasting glucose, liver steatosis and fibrosis in rodents. Thus, PATAS represents a novel first-in-class peptide that targets the adipocyte to ameliorate insulin resistance and its associated comorbidities.

Barded-Biedl syndrome (BBS) is a rare genetic disorder with an unmet medical need for retinal degeneration. Small-molecule drugs were previously identified to slow down the apoptosis of photoreceptors in BBS mouse models. Clinical translation was not practical due to the necessity of repetitive invasive intravitreal injections for pediatric populations. Non-invasive methods of retinal drug targeting are a prerequisite for acceptable adaptation to the targeted pediatric patient population. Here, we present the development and functional testing of a non-invasive, topical, magnetically assisted delivery system, harnessing the ability of magnetic nanoparticles (MNPs) to cargo two drugs (guanabenz and valproic acid) with anti-unfolded protein response (UPR) properties towards the retina. Using magnetic resonance imaging (MRI), we showed the MNPs’ presence in the retina of Bbs wild-type mice, and their photoreceptor localization was validated using transmission electron microscopy (TEM). Subsequent electroretinogram recordings (ERGs) demonstrated that we achieved beneficial biological effects with the magnetically assisted treatment translating the maintained light detection in Bbs−/− mice (KO). To our knowledge, this is the first demonstration of efficient magnetic drug targeting in the photoreceptors in vivo after topical administration. This non-invasive, needle-free technology expands the application of SMDs for the treatment of a vast spectrum of retinal degenerations and other ocular diseases.

International audience; People are able to modify the spontaneous pace of their actions to interact with their environment and others. This ability is underpinned by high-level cognitive functions but little is known in regard to the brain areas that underlie such temporal control. A salient practical issue is that current neuroimaging techniques (e.g., EEG, fMRI) are extremely sensitive to movement, which renders challenging any investigation of brain activity in the realm of whole-body motor paradigms. Within the last decade, the noninvasive imaging method of functional near-infrared spectroscopy (fNIRS) has become the reference tool for experimental motor paradigms due to its tolerance to motion artefacts. In the present study, we used a continuous-wave fNIRS system to record the prefrontal and motor hemodynamic responses of 16 participants, while they performed a spatial-tapping task varying in motor complexity and externally-paced tempi (i.e., 300 ms, 500 ms, 1200 ms). To discriminate between physiological noise and cerebral meaningful signals, the physiological data (i.e., heart and respiratory rates) were recorded so that frequency bands of such signals could be regressed from the fNIRS data. Particular attention was taken to control the precise position of the optodes in reference to the cranio-cerebral correlates of the NIR channels throughout the experimental session. Results indicated that fast pacing relied on greater activity of the motor areas whereas moving at close-to-spontaneous pace placed a heavier load on posterior prefrontal processes. These results provide new insight concerning the role of frontal cognitive control in modulating the pacing of voluntary motor behaviors.

Obesity is a major risk factor for insulin resistance (IR) and its attendant complications. The pathogenic mechanisms linking them remain poorly understood, partly due to a lack of intermediary monogenic human phenotypes. Here, we report on a monogenic form of IR-prone obesity, Alström syndrome (ALMS). Twenty-three subjects with monogenic or polygenic obesity underwent hyperinsulinaemic-euglycemic clamping with concomitant adipose tissue (AT) microdialysis and an in-depth analysis of subcutaneous AT histology. We have shown a relative adipose tissue failure in monogenic obese cohort; a finding supported by observations in a novel conditional mouse model (Almsflin/flin) and ALMS1-silenced human primary adipocytes. Whereas, selective reactivation of ALMS1 gene in adipose tissue of an ALMS conditional knockdown mice model (Almsflin/flin;Adipo-Cre+/-) restores systemic insulin sensitivity and glucose tolerance. Hence, we show for the first time the relative adipose tissue failure in human obese cohorts to be a major determinant of accelerated IR without evidence of lipodystrophy. These new insights into adipocyte driven insulin resistance may assist development of adipose tissue targeted therapeutic strategies for diabetes.

Alström Syndrome (ALMS) is an ultra-rare multisystem genetic disorder caused by autosomal recessive variants in the ALMS1 gene, which is located on chromosome 2p13. ALMS is a multisystem, progressive disease characterised by visual disturbance, hearing impairment, cardiomyopathy, childhood obesity, extreme insulin resistance, accelerated non-alcoholic fatty liver disease (NAFLD), renal dysfunction, respiratory disease, endocrine and urologic disorders. Clinical symptoms first appear in infancy with great variability in age of onset and severity. ALMS has an estimated incidence of 1 case per 1,000,000 live births and ethnically or geographically isolated populations have a higher-than-average frequency. The rarity and complexity of the syndrome and the lack of expertise can lead to delayed diagnosis, misdiagnosis and inadequate care. Multidisciplinary and multiprofessional teams of experts are essential for the management of patients with ALMS, as early diagnosis and intervention can slow the progression of multi-organ dysfunctions and improve patient quality of life.These guidelines are intended to define standard of care for patients suspected or diagnosed with ALMS of any age. All information contained in this document has originated from a systematic review of the literature and the experiences of the authors in their care of patients with ALMS. The Appraisal of Guidelines for Research & Evaluation (AGREE II) system was adopted for the development of the guidelines and for defining the related levels of evidence and strengths of recommendations.These guidelines are addressed to: a) specialist centres, other hospital-based medical teams and staffs involved with the care of ALMS patients, b) family physicians and other primary caregivers and c) patients and their families.

Bardet Biedl syndrome (BBS) is a rare inherited syndromic condition characterized by renal and extra-renal disorders. Renal defect, at either structural or functional level, is one of the cardinal clinical features, and is a major cause of morbidity. However, the pathogenic mechanism underlying its dysfunction remains largely unknown, and to date only symptomatic treatment with no specific therapy is available for these patients. Elucidating aberrant cellular and/or systemic processes that impact kidney function is therefore a prerequisite to develop targeted innovative therapeutic strategies for the BBS patients. Given the proven role of BBS proteins in the function of the primary cilium (PC) and considering the clinical overlapping of BBS with other ciliopathies, BBS is considered the result of disruption of ciliary activities. The present review aims at giving an updated overview of the spectrum of renal abnormalities in BBS patients according to the existing scientific literature, and discusses the possible role of intrinsic PC dysfunction into the pathogenesis of renal defects based on the most recent findings demonstrating a possible role of systemic factors in favoring the progression of renal disease. (c) 2017 The Author(s) Published by S. Karger AG, Basel

The development of an innovative drug delivery system to target, after topical administration, the retina with bioactive agents against retinal pathologies is a major challenge. Currently, the sole approach to target these tissues is through intravitreous injection, but this is not free from problematics such as severe side effects and rapid clearance of small molecules from the vitreous.We aim to synthesize, develop and formulate a new magnetic nanoparticle‐mediated delivery technology that shall allow achieving needle‐free, anesthesia‐free delivery of active drugs to the retina after topical administration assisted by magnetic targeting.

International audience; Cilia are highly conserved and ubiquitously expressed organelles. Ciliary defects of genetic origins lead to ci-liopathies, in which retinal degeneration (RD) is one cardinal clinical feature. In order to efficiently find and design new therapeutic strategies the underlying mechanism of retinal degeneration of three murine model was compared. The rodent models correspond to three emblematic ciliopathies, namely: Bardet-Biedl Syndrome (BBS), Alström Syndrome (ALMS) and CEP290-mediated Leber Congenital Amaurosis (LCA). Scotopic rodent electroretinography (ERG) was used to test the retinal function of mice, Transmitted Electron microscopy (T.E.M) was performed to assess retinal structural defects and real-time PCR for targeted genes was used to monitor the expression levels of the major apoptotic Caspase-related pathways in retinal extracts to identify pathological pathways driving the RD in order to identify potential therapeutic targets. We found that BBS and CEP290-mediated LCA mouse models exhibit perinatal retinal degeneration associated with rhodopsin mis-localization in the photoreceptor and the induction of an Endoplasmic Reticulum (ER) stress. On the other hand, the tested ALMS mouse model, displayed a slower degeneration phenotype, with no Rhodopsin mislocalization nor ER-stress activity. Our data points out that behind the general phenotype of vision loss associated with these ciliopathies, the mechanisms and kinetics of disease progression are different.

Studying rare genetic disorders, associating type 2 diabetes, is a valuable approach to decipher disease origins as a specific causal gene can be linked to the diabetic phenotype. Understanding the related protein functions favors the discovery of new pathways, hence the design of new therapies. We focused on an ultra-rare genetic disorder, the Alström syndrome, associated with severe early-onset type 2 diabetes, obesity, steatosis and generalized fibrosis and for which a unique gene is consistently found mutated in ALMS patients, ALMS1 gene. Combining clinical, multiomics and in vivo mouse data, we discovered that ALMS1 regulates the ultimate steps of insulin signaling in the adipocyte, controlling fusion of GLUT4 sorting vesicles with the plasma membrane. ALMS1 binds to αPKC in the GLUT4 sorting vesicles vicinity and, under insulin stimulus, releases αPKC to trigger GLUT4 plasma membrane entry and glucose absorption. ALMS1 inactivation specifically inhibits adipocyte’s glucose absorption. In mice, the diabetic, steatotic and fibrotic phenotypes were linked to switching adipocyte energy tropism from glucose to lipids corelated with fatty acid transporters’ upregulation like FATP2 in the adipocyte; also observed in ALMS patients’ adipocytes. This change in fuel source in the adipocyte is the underlying cause for the observed metabolic disorders in vivo; primarily mediated through lipid signaling. Insulin-independent glucose absorption was achieved in normal adipocytes using a cell-penetrant, stapled peptide termed PATAS that targets ALMS1/αPKC protein interaction and in vivo can restore physiological adipocyte’s glucose energy tropism. Several in-house and outsourced experiments have demonstrated that PATAS administration significantly improves glucose intolerance, fasting blood glucose levels, liver steatosis and fibrosis in different mouse and rat models thereby making PATAS a potential novel drug to treat type 2 diabetes and its associated complications. Disclosure V. Marion: Research Support; Self; Rhythm Pharmaceuticals, Inc. Stock/Shareholder; Self; ALMS THERAPEUTICS.

Olfactory bulb (OB) volume evaluation by magnetic resonance imaging (MRI) has been demonstrated to be related to olfactory dysfunction in many different diseases. Olfactory dysfunction is often overlooked in Bardet-Biedl syndrome (BBS) patients and is rarely objectively evaluated by MRI. We present a series of 20 BBS patients with olfactory dysfunction. The OB was evaluated separately and blindly by two radiologists (SR and SM) with 3 Tesla MRI imaging comparatively to 12 normal control subjects by global visual evaluation and by quantitative measurement of OB volume. In the 12 control cases OB visual evaluation was considered as normal in all cases for radiologist (SR) and in 10 cases for radiologist (SM). In the 20 BBS patients, OB visual evaluation was considered as abnormal in 18 cases for SR and in all cases for SM. OB volumetric evaluation for SR and SM in BBS patients was able to provide significant correlation between BBS and olfactory dysfunction. This study indicates that OB volume evaluation by MRI imaging like structural MRI scan for gray matter modifications demonstrates that olfactory dysfunction in BBS patients is a constant and cardinal symptom integrated in a genetical syndrome with peripheral and central olfactory structure alterations.

The primary cilium is a specialized organelle, present at the surface of most eukaryotic cells, whose main function is to detect, integrate and transmit intra- and extra-cellular signals. Its dysfunction usually results in a group of severe clinical manifestations nowadays termed ciliopathies. The latter can be of syndromic nature with multi-organ dysfunctions and can also be associated with a morbid obese phenotype, like it is the case in the iconic ciliopathy, the Bardet Biedl syndrome (BBS). This review will discuss the contribution of the unique context offered by the emblematic BBS for understanding the mechanisms leading to obesity via the involvement of the primary cilium together with identification of novel molecular players and signaling pathways it has helped to highlight. In the current context of translational medicine and system biology, this article will also discuss the potential benefits and challenges posed by these techniques via multi-level approaches to better dissect the underlying mechanisms leading to the complex condition of obesity.

Bardet-Biedl syndrome (BBS) is a well-recognized ciliopathy characterized by cardinal features namely: early onset retinitis pigmentosa, polydactyly, obesity, hypogonadism, renal and cognitive impairment. Recently, disorders of olfaction (anosmia, hyposmia) have been also described in BBS patients. Moreover, morphological brain anomalies have been reported and prompt for further investigations to determine whether they are primary or secondary to peripheral organ involvement (i.e. visual or olfactory neuronal tissue). The objective of this article is to evaluate olfactory disorders in BBS patients and to investigate putative correlation with morphological cerebral anomalies. To this end, 20 BBS patients were recruited and evaluated for olfaction using the University of Pennsylvania Smell Identification Test (UPSIT). All of them underwent a structural magnetic resonance imaging (MRI) scan. We first investigated brain morphological differences between BBS subjects and 14 healthy volunteers. Then, we showed objective olfaction disorders in BBS patients and highlight correlation between gray matter volume reduction and olfaction dysfunction in several brain areas.

International audience; IRECT electrical stimulation (DES) has long been used to perform real-time functional mapping of the brain. More recently, this technique was introduced in the neurosurgery of slow-growing and infiltrative brain tumors to guide the resection with great success. By generating transient perturbations, this method allows the real-time identification of both cortical areas and subcortical networks that are essential for the function. Thus, as much as possible, non-functional tissue can be removed while minimizing the sequelae. However, the understanding of the electrophysiological effects of DES and, in particular its remote propagation, remains an open and key question. DES can be used to probe on-line and in-vivo the spatio-temporal connectivity and the dynamics of functional networks by associating electrophysiological recordings. Such methodology has been performed using electrocorticography (ECoG) and implanted grids on the surface of grey matter for pre-surgical planning of drug resistant epileptic patients. Some of these results suggest a local cortico-cortical propagation of evoked potentials (EPs) with DES. However, the propagation through subcortical pathways and at distant sites needs more direct evidences. To investigate more remote effects of DES (i.e. cortico-subcortico-cortical EPs), electroencephalographic (EEG) recordings would be of some interest. Intra-operative EEG recordings were studied to analyze if and how stimulation currents spread at distant sites and more especially if they can be perceptible in the " controlesional " hemisphere. In other words, does DES induce EPs? Does DES modify the frequency contents included in the natural activity of the brain? We also aimed to measure the effects of DES on functional connectivity, i.e. to determine if DES modifies the correlation between the different EEG signals between the pre, intra and post-DES phases. To our knowledge, this approach has never been performed. Data were collected during an awake brain surgery (without interfering with the surgical routine) for one patient harboring a right frontal hemisphere tumor and under local anesthesia. Neural activity was recorded from the surface of the skull (EEG, sampling frequency of 2048 Hz) on 4 sites (3 controlesional sites: F3, C3 and O1 and 1 ipsilesional site: O2; the lesion was centered on F4, Fp2 and F8). DES was delivered with a bipolar electrode using standard parameters (biphasic square pulse, 60 Hz, ~ 2 mA). First we tried to measure EPs when DES is applied cortically and subcortically. To maximize the EPs while minimizing the noise and the artifacts, EEG signals were synchronized and averaged upon a given time window (500 ms). The phases when DES is applied can be recognized by the appearance of artefacts on the natural EEG activity. However, whereas EPs have been observed in ECoG [2, 3], no EP was detected in our EEG data. With a 60 Hz frequency, stimulation artefacts can hide EPs. Indeed, the nervous time of conduction is close to the stimulation period, in particular for the interhemispheric transfer (around 20 ms). Choosing a stimulation frequency lower than 60 Hz could limit artefacts and make the detection of EPs easier. In consequence it is planned to study the time-frequency content of the neural data. To reduce bias and variance problems, multitaper spectral estimation could be used. We will look for modifications of the spectrum for each period of stimulation, before, during and after DES. In addition, functional connectivity also remains to be studied by looking at the correlation between signals from various electrodes, especially between electrodes located in the ipsi vs. controlesional hemisphere. We will present the setup, the data analysis protocol and the preliminary results.

Ciliopathies are heterogeneous disorders sharing different clinical signs due to a defect at the level of the primary cilia/centrosome complex. Postaxial polydactyly is frequently reported in ciliopathies, especially in Bardet-Biedl syndrome (BBS). Clinical features and genetic results observed in a pair of dizygotic twins with BBS are reported. The following manifestations were present: retinitis pigmentosa, bilateral insertional polydactyly, cognitive impairment and renal dysfunction. X-rays of the hands confirmed the presence of a 4th mesoaxial extra-digit with Y-shaped metacarpal bones. The sequencing of LZTFL1 identified a missense mutation (NM_020347.2: p.Leu87Pro; c.260T>C) and a nonsense mutation (p.Glu260*; c.778G>T), establishing a compound heterozygous status for the twins. A major decrease of LZTFL1 transcript and protein was observed in the patient's fibroblasts. This is the second report of LZTFL1 mutations in BBS patients confirming LZTFL1 as a BBS gene. Interestingly, the only two families reported in literature thus far with LZTFL1 mutations have in common mesoaxial polydactyly, a very uncommon feature for BBS. This special subtype of polydactyly in BBS patients is easily identified on clinical examination and prompts for priority sequencing of LZTFL1 (BBS17).

Ciliopathies, a class of rare genetic disorders, present often with retinal degeneration caused by protein transport defects between the inner segment and the outer segment of the photoreceptors. Bardet-Biedl syndrome is one such ciliopathy, genetically heterogeneous with 17 BBS genes identified to date, presenting early onset retinitis pigmentosa. By investigating BBS12-deprived retinal explants and the Bbs12(-/-) murine model, we show that the impaired intraciliary transport results in protein retention in the endoplasmic reticulum. The protein overload activates a proapoptotic unfolded protein response leading to a specific Caspase12-mediated death of the photoreceptors. Having identified a therapeutic window in the early postnatal retinal development and through optimized pharmacological modulation of the unfolded protein response, combining three specific compounds, namely valproic acid, guanabenz, and a specific Caspase12 inhibitor, achieved efficient photoreceptor protection, thereby maintaining light detection ability in vivo.

Summary Studying ciliopathies, like the Bardet-Biedl syndrome (BBS), allow the identification of signaling pathways potentially involved in common diseases, sharing phenotypic features like obesity or type 2 diabetes. Given the close association between obesity and insulin resistance, obese BBS patients would be expected to be insulin resistant. Surprisingly, we found that a majority of obese BBS patients retained normal glucose tolerance and insulin sensitivity. Patient's adipose tissue biopsies revealed upregulation of adipogenic genes and decrease of inflammatory mediators. In vitro studies on human primary mesenchymal stem cells (MSCs) showed that BBS12 inactivation facilitated adipogenesis, increased insulin sensitivity, and glucose utilization. We generated a Bbs12 −/− mouse model to assess the impact of Bbs12 inactivation on adipocyte biology. Despite increased obesity, glucose tolerance was increased with specific enhanced insulin sensitivity in the fat. This correlated with an active recruitment of MSCs resulting in adipose tissue hyperplasia and decreased in inflammation.

Background Bardet–Biedl Syndrome (BBS) is an emblematic recessive genetically highly heterogeneous ciliopathy characterised mainly by polydactyly, retinitis pigmentosa, obesity, cognitive impairment, and kidney dysfunction. The 16 BBS genes known to date are implied in the primary cilia related cellular pathways. Methods and results Single nucleotide polymorphism (SNP) array analysis followed by exome sequencing was performed in a consanguineous family diagnosed with BBS with unusual developmental features, namely situs inversus and insertional polydactyly. A homozygous 5 bp deletion (NM_020347.2:c.402-406del, p.Pro136ThrfsX5) in LZTFL1 was identified. No LZTFL1 transcript was found in the patient's fibroblasts and no protein could be detected. The sonic hedgehog (Shh) pathway analysis conducted on the patient's fibroblast showed a significant increase in Smo. Patched1 as well as the downstream target GLI2 were also found to be upregulated, indicating an overall massive activation of the Shh signalling in the absence of LZTFL1. Conclusion LZTFL1 , encoding the human leucine zipper transcription factor like 1, has been recently shown to be an important negative regulator of BBSome ciliary trafficking and Shh signalling. This study shows that absence of LZTFL1 leads to a BBS phenotype with enhanced developmental abnormalities associated with cellular Shh dysfunction. LZTFL1 is a novel BBS gene ( BBS17 ).

Inherited dental malformations constitute a clinically and genetically heterogeneous group of disorders. Here, we report on a severe developmental dental defect that results in a dentin dysplasia phenotype with major microdontia, oligodontia, and shape abnormalities in a highly consanguineous family. Homozygosity mapping revealed a unique zone on 6q27-ter. The two affected children were found to carry a homozygous mutation in SMOC2. Knockdown of smoc2 in zebrafish showed pharyngeal teeth that had abnormalities reminiscent of the human phenotype. Moreover, smoc2 depletion in zebrafish affected the expression of three major odontogenesis genes: dlx2, bmp2, and pitx2.

Studies of the primary cilium, now known to be present in all cells, have undergone a revolution, in part, because mutation of many of its proteins causes a large number of diseases, including cystic kidney disease. Bardet-Biedl syndrome (BBS) is an inherited ciliopathy characterized, among other dysfunctions, by renal defects for which the precise role of the cilia in kidney function remains unclear. We studied a cohort of patients with BBS where we found that these patients had a urinary concentration defect even when kidney function was near normal and in the absence of major cyst formation. Subsequent in vitro analysis showed that renal cells in which a BBS gene was knocked down were unciliated, but did not exhibit cell cycle defects. As the vasopressin receptor 2 is located in the primary cilium, we studied BBS-derived unciliated renal epithelial cells and found that they were unable to respond to luminal arginine vasopressin treatment and activate their luminal aquaporin 2. The ability to reabsorb water was restored by treating these unciliated renal epithelial cells with forskolin, a receptor-independent adenylate cyclase activator, showing that the intracellular machinery for water absorption was present but not activated. These findings suggest that the luminal receptor located on the primary cilium may be important for efficient transepithelial water absorption. Kidney International (2011) 79, 1013-1025; doi:10.1038/ki2010.538; published online 26 January 2011

The ciliopathies are an expanding group of disorders caused by mutations in genes implicated in the biogenesis and function of primary cilia. Bardet-Biedl syndrome (BBS) is a model ciliopathy characterized by progressive retinal degeneration, obesity, polydactyly, cognitive impairment, kidney anomalies and hypogonadism. Mutations in SDCCAG8(NPHP10) were described recently in patients with nephronophthisis and retinal degeneration (Senior-Loken syndrome; SLS). Given the phenotypic and genetic overlap between known ciliopathy genes, we hypothesized that mutations in SDCCAG8 might also contribute alleles to more severe, multisystemic ciliopathies. We performed genetic and phenotypic analyses of 2 independent BBS cohorts. Subsequent to mutation screening, we made a detailed phenotypic analysis of 5 families mutated for SDCCAG8 (3 homozygous and 2 compound heterozygous mutations) and conducted statistical analyses across both cohorts to examine possible phenotype-genotype correlations with mutations at this locus. All patients with mutations in SDCCAG8 fulfilled the diagnostic criteria for BBS (retinal degeneration, obesity, cognitive defects, renal failure, hypogonadism). Interestingly, none of the patients with primary SDCCAG8 mutations had polydactyly, a frequent but not obligatory BBS feature. In contrast, the same patients displayed early-onset renal failure, obesity, as well as recurrent pulmonary and ENT infections. Comparison of the phenotypes of these families with our entire BBS cohort indicated that renal impairment and absent polydactyly correlated significantly with causal SDCCAG8 mutations. Thus, SDCCAG8 mutations are sufficient to cause BBS in 1–2% of our combined cohorts, and define this gene as the sixteenth BBS locus (BBS16). The absence of polydactyly and the concomitant, apparently fully penetrant association with early kidney failure represents the first significant genotype-phenotype correlation in BBS that potentially represents an indicator for phenotype-driven priority screening and informs specific patient management.

We have identified TUBGCP4 variants in individuals with autosomal-recessive microcephaly and chorioretinopathy. Whole-exome sequencing performed on one family with two affected siblings and independently on another family with one affected child revealed compound-heterozygous mutations in TUBGCP4. Subsequent Sanger sequencing was performed on a panel of individuals from 12 French families affected by microcephaly and ophthalmic manifestations, and one other individual was identified with compound-heterozygous mutations in TUBGCP4. One synonymous variant was common to all three families and was shown to induce exon skipping; the other mutations were frameshift mutations and a deletion. TUBGCP4 encodes γ-tubulin complex protein 4, a component belonging to the γ-tubulin ring complex (γ-TuRC) and known to regulate the nucleation and organization of microtubules. Functional analysis of individual fibroblasts disclosed reduced levels of the γ-TuRC, altered nucleation and organization of microtubules, abnormal nuclear shape, and aneuploidy. Moreover, zebrafish treated with morpholinos against tubgcp4 were found to have reduced head volume and eye developmental anomalies with chorioretinal dysplasia. In summary, the identification of TUBGCP4 mutations in individuals with microcephaly and a spectrum of anomalies in eye development, particularly photoreceptor anomalies, provides evidence of an important role for the γ-TuRC in brain and eye development.

Background Bardet–Biedl Syndrome (BBS) is a genetically heterogeneous ciliopathy with clinical cardinal features including retinal degeneration, obesity and renal dysfunction. To date, 20 BBS genes have been identified with BBS10 being a major BBS gene found to be mutated in almost 20 percent of all BBS patients worldwide. It codes for the BBS10 protein which forms part of a chaperone complex localized at the basal body of the primary cilium. Renal dysfunction in BBS patients is one of the major causes of morbidity in human patients and is associated initially with urinary concentration defects related to water reabsorption impairment in renal epithelial cells. The aim of this study was to study and compare the impact of a total Bbs10 inactivation (Bbs10−/−) with that of a specific renal epithelial cells inactivation (Bbs10 fl/fl; Cdh16-Cre+/−). Results We generated the Bbs10−/−and Bbs10 fl/fl; Cadh16-Cre+/− mouse model and characterized them. Bbs10−/− mice developed obesity, retinal degeneration, structural defects in the glomeruli, polyuria associated with high circulating arginine vasopressin (AVP) concentrations, and vacuolated, yet ciliated, renal epithelial cells. On the other hand, the Bbs10 fl/fl; Cadh16-Cre+/−mice displayed no detectable impairment. Conclusions These data highlight the importance of a systemic Bbs10 inactivation to trigger averted renal dysfunction whereas a targeted absence of BBS10 in the renal epithelium is seemingly non-deleterious. Electronic supplementary material The online version of this article (doi:10.1186/s13630-015-0019-8) contains supplementary material, which is available to authorized users.

The primary cilium is a specialized organelle, present at the surface of most eukaryotic cells, whose main function is to detect, integrate and transmit intra- and extra-cellular signals. Its dysfunction usually results in a group of severe clinical manifestations nowadays termed ciliopathies. The latter can be of syndromic nature with multi-organ dysfunctions and can also be associated with a morbid obese phenotype, like it is the case in the iconic ciliopathy, the Bardet Biedl syndrome (BBS). This review will discuss the contribution of the unique context offered by the emblematic BBS for understanding the mechanisms leading to obesity via the involvement of the primary cilium together with identification of novel molecular players and signaling pathways it has helped to highlight. In the current context of translational medicine and system biology, this article will also discuss the potential benefits and challenges posed by these techniques via multi-level approaches to better dissect the underlying mechanisms leading to the complex condition of obesity.

AIM: Argininosuccinate synthetase (ASS) is essential for recycling L-citrulline, the by-product of NO synthase (NOS), to the NOS substrate L-arginine. Here, we assessed whether disturbed arginine resynthesis modulates endothelium-dependent vasodilatation in normal and diabetic male mice.METHODS AND RESULTS: Endothelium-selective Ass-deficient mice (Assfl/fl/Tie2Cretg/- = Ass-KOTie2) were generated by crossing Assfl/fl mice ( = control) with Tie2Cre mice. Gene ablation in endothelial cells was confirmed by immunohistochemistry. Blood pressure (MAP) was recorded in 34-week-old male mice. Vasomotor responses were studied in isolated saphenous arteries of 12- and 34-week-old Ass-KOTie2 and control animals. At the age of 10 weeks, diabetes was induced in control and Ass-KOTie2 mice by streptozotocin injections. Vasomotor responses of diabetic animals were studied 10 weeks later. MAP was similar in control and Ass-KOTie2 mice. Depletion of circulating L-arginine by arginase 1 infusion or inhibition of NOS activity with L-NAME resulted in an increased MAP (10 and 30 mmHg, respectively) in control and Ass-KOTie2 mice. Optimal arterial diameter, contractile responses to phenylephrine, and relaxing responses to acetylcholine and sodium nitroprusside were similar in healthy control and Ass-KOTie2 mice. However, in diabetic Ass-KOTie2 mice, relaxation responses to acetylcholine and endothelium-derived NO (EDNO) were significantly reduced when compared to diabetic control mice.CONCLUSIONS: Absence of endothelial citrulline recycling to arginine did not affect blood pressure and systemic arterial vasomotor responses in healthy mice. EDNO-mediated vasodilatation was significantly more impaired in diabetic Ass-KOTie2 than in control mice demonstrating that endothelial arginine recycling becomes a limiting endothelial function in diabetes.

Background Bardet–Biedl syndrome (BBS) is a recessive and genetically heterogeneous ciliopathy characterised by retinitis pigmentosa, obesity, kidney dysfunction, postaxial polydactyly, behavioural dysfunction and hypogonadism. 7 of the 17 BBS gene products identified to date assemble together with the protein BBIP1/BBIP10 into the BBSome, a protein complex that ferries signalling receptors to and from cilia. Methods and results Exome sequencing performed on a sporadic BBS case revealed for the first time a homozygous stop mutation (NM_001195306: c.173T>G, p.Leu58*) in the BBIP1 gene. This mutation is pathogenic since no BBIP1 protein could be detected in fibroblasts from the patient, and BBIP1[Leu58*] is unable to associate with the BBSome subunit BBS4. Conclusions These findings identify BBIP1 as the 18th BBS gene ( BBS18 ) and suggest that BBSome assembly may represent a unifying pathomechanism for BBS.

Suckling mammals, including mice, differ from adults in the abundant expression of enzymes that synthesize arginine from citrulline in their enterocytes. To investigate the importance of the small-intestinal arginine synthesis for whole-body arginine production in suckling mice, we floxed exon 13 of the argininosuccinate synthetase (Ass) gene, which codes for a key enzyme in arginine biosynthesis, and specifically and completely ablated Ass in enterocytes by crossing Ass (fl) and Villin-Cre mice. Unexpectedly, Ass (fl/fl) /VilCre (tg/-) mice showed no developmental impairments. Amino-acid fluxes across the intestine, liver, and kidneys were calculated after determining the blood flow in the portal vein, and hepatic and renal arteries (86%, 14%, and 33%, respectively, of the transhepatic blood flow in 14-day-old mice). Relative to control mice, citrulline production in the splanchnic region of Ass (fl/fl) /VilCre (tg/-) mice doubled, while arginine production was abolished. Furthermore, the net production of arginine and most other amino acids in the liver of suckling control mice declined to naught or even changed to consumption in Ass (fl/fl) /VilCre (tg/-) mice, and had, thus, become remarkably similar to that of post-weaning wild-type mice, which no longer express arginine-biosynthesizing enzymes in their small intestine. The adaptive changes in liver function were accompanied by an increased expression of genes involved in arginine metabolism (Asl, Got1, Gpt2, Glud1, Arg1, and Arg2) and transport (Slc25a13, Slc25a15, and Slc3a2), whereas no such changes were found in the intestine. Our findings suggest that the genetic premature deletion of arginine synthesis in enterocytes causes a premature induction of the post-weaning pattern of amino-acid metabolism in the liver.

Mutations in the DYNC1H1 gene encoding for dynein heavy chain cause two closely related human motor neuropathies, dominant spinal muscular atrophy with lower extremity predominance (SMA-LED) and axonal Charcot-Marie-Tooth (CMT) disease, and lead to sensory neuropathy and striatal atrophy in mutant mice. Dynein is the molecular motor carrying mitochondria retrogradely on microtubules, yet the consequences of dynein mutations on mitochondrial physiology have not been explored. Here, we show that mouse fibroblasts bearing heterozygous or homozygous point mutation in Dync1h1, similar to human mutations, show profoundly abnormal mitochondrial morphology associated with the loss of mitofusin 1. Furthermore, heterozygous Dync1h1 mutant mice display progressive mitochondrial dysfunction in muscle and mitochondria progressively increase in size and invade sarcomeres. As a likely consequence of systemic mitochondrial dysfunction, Dync1h1 mutant mice develop hyperinsulinemia and hyperglycemia and progress to glucose intolerance with age. Similar defects in mitochondrial morphology and mitofusin levels are observed in fibroblasts from patients with SMA-LED. Last, we show that Dync1h1 mutant fibroblasts show impaired perinuclear clustering of mitochondria in response to mitochondrial uncoupling. Our results show that dynein function is required for the maintenance of mitochondrial morphology and function with aging and suggest that mitochondrial dysfunction contributes to dynein-dependent neurological diseases, such as SMA-LED.

Ciliopathies are responsible for multiple organ dysfunctions with chronic kidney disease as one of cardinal clinical features. We studied the renal phenotype in 33 patients diagnosed with Bardet-Biedl Syndrome (BBS) and found renal abnormalities to be present in 82% of patients (27/33). An impaired urinary concentrating ability was the most frequent manifestation (63%, 19/30) in non dialyzed and non transplanted patients, which could be observed even in the absence of renal failure or cystic formation identified by ultrasonographic and magnetic resonance imaging. In order to specify the pathophysiology involved in this urinary concentrating defect, we focused on the role of the primary cilia and its interaction with the anti-diuretic hormone, arginine-vasopressin (AVP) as it was previously shown that the AVP-Receptor-2 (AVPR2) was localized on the primary cilia. To do so, we studied the effects of vertebrate-specific chaperonin-like proteins (BBS6, 10 and 12) inactivation in cultured cell line HCD (Human Collecting Duct) by way of RNA interference techniques. Our results show that chaperonin-like proteins deprivation in vitro leads to primary cilia loss in HCD cells, resulting in an inability to detect luminal AVP and to activate the targeting of aquaporin-2 (AQP-2) to the apical membrane of the renal epithelial cell, thus unable to absorb water. Interestingly, water reabsorption through restored targeting of AQP-2 was achieved by forskolin treatment – a receptor-independent adenylate cyclase activator – demonstrating that intracellular machinery was present but not activated. This study highlights the major role of primary cilia in efficient water reabsorption in the collecting duct.

Suckling "F/A2" mice, which overexpress arginase-I in their enterocytes, develop a syndrome (hypoargininemia, reduced hair and muscle growth, impaired B-cell maturation) that resembles IGF1 deficiency. The syndrome may result from an impaired function of the GH-IGF1 axis, activation of the stress-kinase GCN2, and/or blocking of the mTORC1-signaling pathway. Arginine deficiency inhibited GH secretion and decreased liver Igf1 mRNA and plasma IGF1 concentration, but did not change muscle IGF1 concentration. GH supplementation induced Igf1 mRNA synthesis, but did not restore growth, ruling out direct involvement of the GH-IGF1 axis. In C2C12 muscle cells, arginine withdrawal activated GCN2 signaling, without impacting mTORC1 signaling. In F/A2 mice, the reduction of plasma and tissue arginine concentrations to similar to 25% of wild-type values activated GCN2 signaling, but mTORC1-mediated signaling remained unaffected. Gcn2-deficient F/A2 mice suffered from hypoglycemia and died shortly after birth. Because common targets of all stress kinases (eIF2 alpha phosphorylation, Chop mRNA expression) were not increased in these mice, the effects of arginine deficiency were solely mediated by GCN2

Summary Background and Objectives Bardet-Biedl Syndrome (BBS) is a rare autosomal recessive ciliopathy with a wide spectrum of clinical features including obesity, retinitis pigmentosa, polydactyly, mental retardation, hypogonadism, and renal abnormalities. The molecular genetic profile of BBS is currently being investigated after the recent identification of 14 BBS genes involved in primary cilia-linked disease. This study aims to characterize the renal and cardiovascular presentations and to analyze possible relationships between genotypes and clinical phenotypes. Design, setting, participants & measurements This clinical study was performed in a national cohort of 33 BBS patients, 22 men and 11 women, all aged >16 years (mean age 26.3 years). Results Renal abnormalities, including impairment of renal function and signs of chronic interstitial nephropathy of dysplastic nature, were documented in 82% of the patients. Cardiovascular evaluations revealed that this group of young patients had significant cardiovascular risk factors. Hypertension was found in >30% of the patients and hyperlipidemia in >60%, and almost 50% had other metabolic abnormalities. Overt diabetes was present in only 6%. With regard to genotype-phenotype correlation, patients with a mutation in the BBS6, BBS10, or BBS12 gene (10 of 33 patients) had more severe renal disease. Conclusions Our study results confirm the frequent occurrence of renal involvement in patients with BBS, underscore the high risk of cardiovascular disease in these patients, and provide new information on a possible genotype-phenotype correlation.

International audience; Bardet-Biedl syndrome (BBS), an emblematic disease in the rapidly evolving field of ciliopathies, is characterized by pleiotropic clinical features and extensive genetic heterogeneity. To date, 14 BBS genes have been identified, 3 of which have been found mutated only in a single BBS family each (BBS11/TRIM32, BBS13/MKS1 and BBS14/MKS4/NPHP6). Previous reports of systematic mutation detection in large cohorts of BBS families (n > 90) have dealt only with a single gene, or at most small subsets of the known BBS genes. Here we report extensive analysis of a cohort of 174 BBS families for 12/14 genes, leading to the identification of 28 novel mutations. Two pathogenic mutations in a single gene have been found in 117 families, and a single heterozygous mutation in 17 families (of which 8 involve the BBS1 recurrent mutation, M390R). We confirm that BBS1 and BBS10 are the most frequently mutated genes, followed by BBS12. No mutations have been found in BBS11/TRIM32, the identification of which as a BBS gene only relies on a single missense mutation in a single consanguineous family. While a third variant allele has been observed in a few families, they are in most cases missenses of uncertain pathogenicity, contrasting with the type of mutations observed as two alleles in a single gene. We discuss the various strategies for diagnostic mutation detection, including homozygosity mapping and targeted arrays for the detection of previously reported mutations.

International audience; Hydrometrocolpos and polydactyly diagnosed in the prenatal period or early childhood may raise diagnostic dilemmas especially in distinguishing McKusick-Kaufman syndrome (MKKS) and the Bardet-Biedl syndrome (BBS). These two conditions can initially overlap. With time, the additional features of BBS appearing in childhood, such as retinitis pigmentosa, obesity, learning disabilities and progressive renal dysfunction allow clear differentiation between BBS and MKKS. Genotype overlap also exists, as mutations in the MKKS-BBS6 gene are found in both syndromes. We report 7 patients diagnosed in the neonatal period with hydrometrocolpos and polydactyly who carry mutations in various BBS genes (BBS6, BBS2, BBS10, BBS8 and BBS12), stressing the importance of wide BBS genotyping in patients with this clinical association for diagnosis, prognosis and genetic counselling.

International audience; Bardet-Biedl syndrome (BBS) is an inherited ciliopathy generally associated with severe obesity, but the underlying mechanism remains hypothetical and is generally proposed to be of neuroendocrine origin. In this study, we show that while the proliferating preadipocytes or mature adipocytes are nonciliated in culture, a typical primary cilium is present in differentiating preadipocytes. This transient cilium carries receptors for Wnt and Hedgehog pathways, linking this organelle to previously described regulatory pathways of adipogenesis. We also show that the BBS10 and BBS12 proteins are located within the basal body of this primary cilium and inhibition of their expression impairs ciliogenesis, activates the glycogen synthase kinase 3 pathway, and induces peroxisome proliferator-activated receptor nuclear accumulation, hence favoring adipogenesis. Moreover, adipocytes derived from BBS-patients' dermal fibroblasts in culture exhibit higher propensity for fat accumulation when compared to controls. This strongly suggests that a peripheral primary dysfunction of adipogenesis participates to the pathogenesis of obesity in BBS.

The autosomal recessive disorder, Bardet-Biedl syndrome (BBS) is an iconic ciliopathy, clinically characterized by obesity, retinopathy, polydactyly and renal dysfunction. To date, 19 BBS genes have been identified, with BBS10 being one of the most commonly mutated genes in human patients. The historical origin of the BBS-induced obesity has been associated with leptin resistance correlated with hyperleptinemia as well as decreased signaling in the appetite-governing arcuate nucleus neurons (ARC) of the hypothalamus. The ARC controls energy homeostasis, food intake and energy expenditure, through the detection of peripheral hormones by POMC and AgRP/NPY expressing neurons. POMC neurons are anorexigenic while NPY/AgRP are orexigenic, and both are ciliated cells. Several hormone receptors have ciliary localization, as the leptin receptor, and inactivation of the BBS proteins results in their mislocalization and signaling impairment. The present work aims at investigating the origins of obesity in the BBS by comparing the phenotype of a BBS10 total knockout (Bbs10-/-) with that of two BBS10 hypothalamic-specific KO mice: namely the POMC (Bbs10fl/fl;POMC-Cre+/-) and the AgRP (Bbs10fl/fl;AgRP-Cre+/-). Bbs10-/- mice develop obesity, together with other BBS cardinal traits, but surprisingly, both Bbs10fl/fl;AgRP-Cre+/- and Bbs10fl/fl;POMC-Cre+/- display a lean phenotype. Further characterizations of these mice highlighted the activation of compensatory mechanisms in response to the specific BBS10 inactivation probably forestalling the obese phenotype. These results indicate the complexity of the BBS-related obese phenotype, and support the need for an integrative approach that would include the contribution of other peripheral organs to better understand the origins of obesity in BBS.

International audience; Context: Sport training enhances the ability to use somato-sensory and otolithic information, which improves postural capabilities. Postural changes are different according to the sport practiced, but few authors have analyzed subjects' postural performances to discriminate the expertise level among highly skilled athletes within a specific discipline. Objective: To compare the postural performance and the postural strategy between soccer players at different levels of competition (national and regional). Design: Repeated measures with 1 between-groups factor (lev-el of competition: national or regional) and 1 within-groups factor (vision: eyes open or eyes closed). Dependent variables were center of pressure surface area and velocity; total spectral energy; and percentage of low-, medium-, and high-frequency band. Setting: Sports performance laboratory. Patients or Other Participants: Fifteen national male soccer players (age ϭ 24 Ϯ 3 years, height ϭ 179 Ϯ 5 cm, mass ϭ 72 Ϯ 3 kg) and 15 regional male soccer players (age ϭ 23 Ϯ 3 years, height ϭ 174 Ϯ 4 cm, mass ϭ 68 Ϯ 5 kg) participated in the study. Intervention(s): The subjects performed posturographic tests with eyes open and closed. Main Outcome Measure(s): While subjects performed static and dynamic posturographic tests, we measured the center of foot pressure on a force platform. Spatiotemporal center-of-pressure measurements were used to evaluate the postural performance, and a frequency analysis of the center-of-pressure excursions (fast Fourier transform) was conducted to estimate the postural strategy. Results: Within a laboratory task, national soccer players produced better postural performances than regional players and had a different postural strategy. The national players were more stable than the regional players and used proprioception and vision information differently. Conclusions: In the test conditions specific to playing soccer , level of playing experience influenced postural control performance measures and strategies. P ostural regulation is organized in hierarchic and stereotypic patterns 1 and requires the integration of afferent information from the visual, vestibular, and proprioceptive systems. 2 Sport training enhances the ability to use somatosensory and otolithic information, which improves postural capabilities. 3 Postural changes are different according to the sport practiced. 4 For example, judo training leads to greater importance being placed on somatosensory information, whereas dance training results in more attention to visual information. 5 Each sport develops specific postural adaptations that are not transferable to the usual upright postures. 6,7 Indeed, Asseman et al 6 evaluated elite gymnasts in 3 postural conditions: bipedal, unipedal, and hand-stands. The gymnasts who were best in the specific unipedal or handstand conditions were not the same as those who were best in the nonspecific bipedal task. Even though nonspecific tasks such as bipedal stance are typically used in activities of daily living, in athletes, it is more relevant to evaluate postural abilities in specific conditions relative to the particular sport. Soccer requires a unipedal posture to perform different technical movements (eg, shooting, passing). The stability of the supporting foot turns out to be critical to shoot as accurately as possible. Therefore, soccer players' postural control should be evaluated in a unipedal stance to respect the specific conditions of soccer. Previous authors have studied soccer players' postural control in a unipedal stance to reduce the risk of traumatic injuries to the lower extremities 8 or to evaluate the effects of rehabilitative training of the ankle joint. 9,10 However, as far as we know, no study has yet been carried out comparing postural performance and strategy in soccer players of different levels of expertise. The postural performance can be characterized by the ability to minimize postural sway, and the postural strategy corresponds to the preferential involvement of short or long neuronal loops in balance regulation. Our aim was to compare postural performance and strategy in unipedal stance between players at different levels of soccer competition .

Human cytomegalovirus (HCMV) is known to carry host cell-derived proteins and mRNAs whose role in cell infection is not understood. We have identified a phospholipase A2 (PLA2) activity borne by HCMV by using an assay based on the hydrolysis of fluorescent phosphatidylcholine. This activity was found in all virus strains analyzed and in purified strains. It was calcium dependent and was sensitive to inhibitors of cytosolic PLA2 (cPLA2) but not to inhibitors of soluble PLA2 or calcium-independent PLA2. No other phospholipase activity was detected in the virus. Purified virus was found to contain human cellular cPLA2α, as detected by monoclonal antibody. No homology with PLA2 was found in the genome of HCMV, indicating that HCMV does not code for a PLA2. Decreased de novo expression of immediate-early proteins 1 and 2 (IE1 and IE2), tegument phosphoprotein pp65, and virus production was observed when HCMV was treated with inhibitors of cPLA2. Cell entry of HCMV was not altered by those inhibitors, suggesting the action of cPLA2 was postentry. Together, our results indicate a selective sorting of a cell-derived cPLA2 during HCMV maturation, which is further required for infectivity.

Primary cilia play key roles in development, cell signalling and cancer, and are involved in signal transduction pathways such as Hh and Wnt signalling. The adrenal cortex produces steroid hormones essential for controlling homeostasis and mediating the stress response. Signalling pathways involved in the process of its development and differentiation are still being identified but include Hh and Wnt, and adrenal development is thus likely to require cilia. I have demonstrated that inhibiting cilia formation, using siRNA targeted to different ciliary components, results in reduced differentiation of the human adrenal carcinoma cell line H295R towards a zona glomerulosa (zG)-like phenotype. These data suggest that primary cilia play a key role in adrenal differentiation, but which signalling pathways are involved still remains unclear. I have also discovered that adrenals from Bardet-Biedl syndrome (BBS) mice, the most prominently studied ciliopathy, have thin capsules, the proposed adrenal stem cell niche, and abnormal histology, while zebrafish embryos injected with morpholinos targeting BBS genes show delayed and reduced expression of ff1b, a marker of interrenal tissue. These data further suggest a role for primary cilia in adrenal development and maintenance. These studies are the foundation for elucidating the role of primary cilia in the development and function of the adrenal gland, and furthering our understanding of adrenocortical development. This promises to lead to improved management of adrenal dysfunction, and demonstrating that adrenal defects are a characteristic of ciliopathies will potentially inform new strategies for patient care.

Many human diseases are linked to mutations in genes encoding membrane trafficking proteins, among them the X-linked centronuclear myopathy (XLCNM) and ciliopathies. We use yeast Saccharomyces cerevisiae as a model system to study these human disease trafficking genes. It is a good model because yeast and human cells present similar intracellular organization and its membrane trafficking and metabolism are well characterized. We first studied the MTM1 gene, responsible for XLCNM, which codes for a myotubularin, a lipid phosphatase required for endosomal sorting. The heterologous expression of wild-type MTM1 or XLCNM patient mutants in yeast allowed comparing their in vivo phosphatase activity and their cellular function in trafficking. The yeast results showed that the phosphatase activity is not defective in patient mutants, further confirmed in the mouse Mtm1 KO model for myopathy [1]. Ciliopathies are complex genetic disorders that result from defects in the formation and/or function of the primary cilium. They include disorders such as Bardet-Biedl syndrome (BBS), Joubert syndrome (JBTS) and Alstrom syndrome (ALS) [2]. Cilia are involved in development and in signaling cascades. Despite, the identification of a large number of genes involved in ciliopathies (http://www.syscilia.org/goldstandard.shtml), the molecular and cellular mechanisms by which they cause the disease are largely unknown. In collaboration with the laboratory of Helene Dollfus, we aim at understanding the cellular roles of membrane trafficking genes involved in ciliopathies by using the yeast model system. Indeed, organization of the primary cilium depends on membrane trafficking since many genes linked to ciliopathies are involved in membrane trafficking [3].