Pharmacological targeting of AKAP-directed compartmentalized cAMP signalling

The second messenger cyclic adenosine monophosphate (cAMP) can bind and activate protein kinase A (PKA). The cAMP/PKA system is ubiquitous and involved in a wide array of biological processes and therefore requires tight spatial and temporal regulation. Important components of the safeguard system are the A-kinase anchoring proteins (AKAPs), a heterogeneous family of scaffolding proteins defined by its ability to directly bind PKA. AKAPs tether PKA to specific subcellular compartments, and they bind further interaction partners to create local signalling hubs. The recent discovery of new AKAPs and advances in the field that shed light on the relevance of these hubs for human disease highlight unique opportunities for pharmacological modulation. This review exemplifies how interference with signalling, particularly cAMP signalling, at such hubs can reshape signalling responses and discusses how this could lead to novel pharmacological concepts for the treatment of disease with an unmet medical need such as cardiovascular disease and cancer

Estimating the number of livebirths to Hepatitis C seropositive women in England in 2013 and 2018 using Bayesian modelling.

BACKGROUND: The UK National Screening Committee currently recommends against antenatal screening for Hepatitis C virus (HCV) infection in England due to lack of HCV prevalence data and treatment licensed for use in pregnancy. We aimed to produce regional and national estimates of the number and proportion of livebirths to HCV seropositive women in England in 2013 and 2018. METHODS: A logistic regression model fitted in the Bayesian framework estimated probabilities of HCV seropositivity among 24,599 mothers delivering in the North Thames area of England in 2012 adjusted by maternal age and region of birth. These probabilities were applied to the underlying population structures of women delivering livebirths in England in 2013 and 2018 to estimate the number of livebirths to HCV seropositive women in these years nationally and by region. The Bayesian approach allowed the uncertainty associated with all estimates to be properly quantified. RESULTS: Nationally, the estimated number of livebirths to women seropositive for HCV for England was 464 (95% credible interval [CI] 300-692) in 2013 and 481 (95%CI 310-716) in 2018, or 70.0 (95%CI 45.0-104.1) per 100,000 and 76.9 (95%CI 49.5-114.4) per 100,000 in these years respectively. Regions with the highest estimated number of livebirths to HCV seropositive women in 2013 and 2018 included London with 118.5 and 124.4 and the South East with 67.0 and 74.0 per 100,000 livebirths. CONCLUSION: Few previous studies have investigated HCV among pregnant women in England. These findings complement and supplement existing research by providing national and regional estimates for the number of livebirths to HCV seropositive women in England. Bayesian modelling allows future national and regional estimates to be produced and the associated uncertainty to be properly quantified

The A-kinase anchoring protein (AKAP) glycogen synthase kinase 3β interaction protein (GSKIP) regulates β-catenin through its interactions with both protein kinase A (PKA) and GSK3β

The A-kinase anchoring protein (AKAP) GSK3beta interaction protein (GSKIP) is a cytosolic scaffolding protein binding protein kinase A (PKA) and glycogen synthase kinase 3beta (GSK3beta). Here we show that both the AKAP function of GSKIP, i.e. its direct interaction with PKA, and its direct interaction with GSK3beta are required for the regulation of beta-catenin and thus Wnt signaling. A cytoplasmic destruction complex targets beta-catenin for degradation and thus prevents Wnt signaling. Wnt signals cause beta-catenin accumulation and translocation into the nucleus, where it induces Wnt target gene expression. GSKIP facilitates control of the beta-catenin stabilizing phosphorylation at Ser-675 by PKA. Its interaction with GSK3beta facilitates control of the destabilizing phosphorylation of beta-catenin at Ser-33/Ser-37/Thr-41. The influence of GSKIP on beta-catenin is explained by its scavenger function; it recruits the kinases away from the destruction complex without forming a complex with beta-catenin. The regulation of beta-catenin by GSKIP is specific for this AKAP as AKAP220, which also binds PKA and GSK3beta, did not affect Wnt signaling. We find that the binding domain of AKAP220 for GSK3beta is a conserved GSK3beta interaction domain (GID), which is also present in GSKIP. Our findings highlight an essential compartmentalization of both PKA and GSK3beta by GSKIP, and ascribe a function to a cytosolic AKAP-PKA interaction as a regulatory factor in the control of canonical Wnt signaling. Wnt signaling controls different biological processes, including embryonic development, cell cycle progression, glycogen metabolism, and immune regulation; deregulation is associated with diseases such as cancer, type 2 diabetes, inflammatory, and Alzheimer's and Parkinson's diseases

Citron kinase controls abscission through RhoA and Anillin.

The small GTPase RhoA plays a crucial role in the different stages of cytokinesis, including contractile ring formation, cleavage furrow ingression, and midbody abscission. Citron kinase (CIT-K), a protein required for cytokinesis and conserved from insects to mammals, is currently considered a cytokinesis-specific effector of active RhoA. In agreement with previous observations, we show here that, as in Drosophila cells, CIT-K is specifically required for abscission in mammalian cells. However, in contrast with the current view, we provide evidence that CIT-K is an upstream regulator rather than a downstream effector of RhoA during late cytokinesis. In addition, we show that CIT-K is capable of physically and functionally interacting with the actin-binding protein anillin. Active RhoA and anillin are displaced from the midbody in CIT-K-depleted cells, while only anillin, but not CIT-K, is affected if RhoA is inactivated in late cytokinesis. The overexpression of CIT-K and of anillin leads to abscission delay. However, the delay produced by CIT-K overexpression can be reversed by RhoA inactivation, while the delay produced by anillin overexpression is RhoA-independent. Altogether, these results indicate that CIT-K is a crucial abscission regulator that may promote midbody stability through active RhoA and anillin

Methodology of Natsal-COVID Wave 1: a large, quasi-representative survey with qualitative follow-up measuring the impact of COVID-19 on sexual and reproductive health in Britain [version 1; peer review: awaiting peer review]

Background: Britain’s National Surveys of Sexual Attitudes and Lifestyles (Natsal) have been undertaken decennially since 1990 and provide a key data source underpinning sexual and reproductive health (SRH) policy. The COVID-19 pandemic disrupted many aspects of sexual lifestyles, triggering an urgent need for population-level data on sexual behaviour, relationships, and service use at a time when gold-standard in-person, household-based surveys with probability sampling were not feasible. We designed the Natsal-COVID study to understand the impact of COVID-19 on the nation’s SRH and assessed the sample representativeness. Methods: Natsal-COVID Wave 1 data collection was conducted four months (29/7-10/8/2020) after the announcement of Britain’s first national lockdown (23/03/2020). This was an online web-panel survey administered by survey research company, Ipsos MORI. Eligible participants were resident in Britain, aged 18-59 years, and the sample included a boost of those aged 18-29. Questions covered participants’ sexual behaviour, relationships, and SRH service use. Quotas and weighting were used to achieve a quasi-representative sample of the British general population. Participants meeting criteria of interest and agreeing to recontact were selected for qualitative follow-up interviews. Comparisons were made with contemporaneous national probability surveys and Natsal-3 (2010-12) to understand bias. Results: 6,654 participants completed the survey and 45 completed follow-up interviews. The weighted Natsal-COVID sample was similar to the general population in terms of gender, age, ethnicity, rurality, and, among sexually-active participants, numbers of sexual partners in the past year. However, the sample was more educated, contained more sexually-inexperienced people, and included more people in poorer health. Conclusions: Natsal-COVID Wave 1 rapidly collected quasi-representative population data to enable evaluation of the early population-level impact of COVID-19 and lockdown measures on SRH in Britain and inform policy. Although sampling was less representative than the decennial Natsals, Natsal-COVID will complement national surveillance data and Natsal-4 (planned for 2022)

Cyclin-dependent kinase 18 controls trafficking of aquaporin-2 and its abundance through ubiquitin ligase STUB1, which functions as an AKAP

Arginine-vasopressin (AVP) facilitates water reabsorption in renal collecting duct principal cells through regulation of the water channel aquaporin-2 (AQP2). The hormone binds to vasopressin V2 receptors (V2R) on the surface of the cells and stimulates cAMP synthesis. The cAMP activates protein kinase A (PKA), which initiates signaling that causes an accumulation of AQP2 in the plasma membrane of the cells facilitating water reabsorption from primary urine and fine-tuning of body water homeostasis. AVP-mediated PKA activation also causes an increase in the AQP2 protein abundance through a mechanism that involves dephosphorylation of AQP2 at serine 261 and a decrease in its poly-ubiquitination. However, the signaling downstream of PKA that controls the localization and abundance of AQP2 is incompletely understood. We carried out an siRNA screen targeting 719 kinase-related genes, representing the majority of the kinases of the human genome and analyzed the effect of the knockdown on AQP2 by high-content imaging and biochemical approaches. The screening identified 13 hits whose knockdown inhibited the AQP2 accumulation in the plasma membrane. Amongst the candidates was the so far hardly characterized cyclin-dependent kinase 18 (CDK18). Our further analysis revealed a hitherto unrecognized signalosome comprising CDK18, an E3 ubiquitin ligase, STUB1 (CHIP), PKA and AQP2 that controls the localization and abundance of AQP2. CDK18 controls AQP2 through phosphorylation at serine 261 and STUB1-mediated ubiquitination. STUB1 functions as an A-kinase anchoring protein (AKAP) tethering PKA to the protein complex and bridging AQP2 and CDK18. The modulation of the protein complex may lead to novel concepts for the treatment of disorders which are caused or are associated with dysregulated AQP2 and for which a satisfactory treatment is not available, e.g., hyponatremia, liver cirrhosis, diabetes insipidus, ADPKD or heart failure

Late post-operative paraparesis after rib penetration of the spinal canal in a patient with neurofibromatous scoliosis

Rib displacement into the spinal canal is a rare cause of paraplegia or paraparesis in patients affected by neurofibromatous scoliosis. We describe a case of paraparesis in a 14-year-old child affected by neurofibromatous dystrophic kyphoscoliosis, treated with combined posterior and anterior spinal arthrodesis. Seventeen days after the surgical treatment the patient developed clinical signs and symptoms of paraparesis. A CT scan showed the head of the fifth rib protruding into the spinal canal with cord compression. Rib resection and posterior cord decompression were carried out following complete neurological recovery

Th17-Related Genes and Celiac Disease Susceptibility

Th17 cells are known to be involved in several autoimmune or inflammatory diseases. In celiac disease (CD), recent studies suggest an implication of those cells in disease pathogenesis. We aimed at studying the role of genes relevant for the Th17 immune response in CD susceptibility. A total of 101 single nucleotide polymorphisms (SNPs), mainly selected to cover most of the variability present in 16 Th17-related genes (IL23R, RORC, IL6R, IL17A, IL17F, CCR6, IL6, JAK2, TNFSF15, IL23A, IL22, STAT3, TBX21, SOCS3, IL12RB1 and IL17RA), were genotyped in 735 CD patients and 549 ethnically matched healthy controls. Case-control comparisons for each SNP and for the haplotypes resulting from the SNPs studied in each gene were performed using chi-square tests. Gene-gene interactions were also evaluated following different methodological approaches. No significant results emerged after performing the appropriate statistical corrections. Our results seem to discard a relevant role of Th17 cells on CD risk

Lack of association of the CIITA -168A→G promoter SNP with myasthenia gravis and its role in autoimmunity

<p>Abstract</p> <p>Background</p> <p>The major histocompatibility complex class II transactivator (CIITA) regulates MHC class II gene expression. A promoter SNP -168A→G (rs3087456) has previously been shown to be associated with susceptibility to several immune mediated disorders, including rheumatoid arthritis (RA), multiple sclerosis (MS) and myocardial infarction (MI). Myasthenia gravis (MG) is an autoimmune disorder which has previously been shown to be associated with polymorphisms of several autoimmune predisposing genes, including <it>IL-1</it>, <it>PTPN22</it>, <it>TNF-α </it>and the <it>MHC</it>. In order to determine if allelic variants of rs3087456 increase predisposition to MG, we analyzed this SNP in our Swedish cohort of 446 MG patients and 1866 controls.</p> <p>Results</p> <p>No significant association of the SNP with MG was detected, neither in the patient group as a whole, nor in any clinical subgroup. The vast majority of previous replication studies have also not found an association of the SNP with autoimmune disorders.</p> <p>Conclusions</p> <p>We thus conclude that previous findings with regard to the role of the <it>CIITA </it>-168A→G SNP in autoimmunity may have to be reconsidered.</p