Integrative analysis identifies key molecular signatures underlying neurodevelopmental deficits in fragile X syndrome

BACKGROUND: Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by epigenetic silencing of FMR1 and loss of FMRP expression. Efforts to understand the molecular underpinnings of the disease have been largely performed in rodent or nonisogenic settings. A detailed examination of the impact of FMRP loss on cellular processes and neuronal properties in the context of isogenic human neurons remains lacking. METHODS: Using CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 to introduce indels in exon 3 of FMR1, we generated an isogenic human pluripotent stem cell model of FXS that shows complete loss of FMRP expression. We generated neuronal cultures and performed genome-wide transcriptome and proteome profiling followed by functional validation of key dysregulated processes. We further analyzed neurodevelopmental and neuronal properties, including neurite length and neuronal activity, using multielectrode arrays and patch clamp electrophysiology. RESULTS: We showed that the transcriptome and proteome profiles of isogenic FMRP-deficient neurons demonstrate perturbations in synaptic transmission, neuron differentiation, cell proliferation and ion transmembrane transporter activity pathways, and autism spectrum disorder-associated gene sets. We uncovered key deficits in FMRP-deficient cells demonstrating abnormal neural rosette formation and neural progenitor cell proliferation. We further showed that FMRP-deficient neurons exhibit a number of additional phenotypic abnormalities, including neurite outgrowth and branching deficits and impaired electrophysiological network activity. These FMRP-deficient related impairments have also been validated in additional FXS patient-derived human-induced pluripotent stem cell neural cells. CONCLUSIONS: Using isogenic human pluripotent stem cells as a model to investigate the pathophysiology of FXS in human neurons, we reveal key neural abnormalities arising from the loss of FMRP.Peer reviewe

Intrinsic mutant HTT-mediated defects in oligodendroglia cause myelination deficits and behavioral abnormalities in Huntington disease

White matter abnormalities are a nearly universal pathological feature of neurodegenerative disorders including Huntington disease (HD). A long-held assumption is that this white matter pathology is simply a secondary outcome of the progressive neuronal loss that manifests with advancing disease. Using a mouse model of HD, here we show that white matter and myelination abnormalities are an early disease feature appearing before the manifestation of any behavioral abnormalities or neuronal loss. We further show that selective inactivation of mutant huntingtin (mHTT) in the NG2+ oligodendrocyte progenitor cell population prevented myelin abnormalities and certain behavioral deficits in HD mice. Strikingly, the improvements in behavioral outcomes were seen despite the continued expression of mHTT in nonoligodendroglial cells including neurons, astrocytes, and microglia. Using RNA-seq and ChIP-seq analyses, we implicate a pathogenic mechanism that involves enhancement of polycomb repressive complex 2 (PRC2) activity by mHTT in the intrinsic oligodendroglial dysfunction and myelination deficits observed in HD. Our findings challenge the long-held dogma regarding the etiology of white matter pathology in HD and highlight the contribution of epigenetic mechanisms to the observed intrinsic oligodendroglial dysfunction. Our results further suggest that ameliorating white matter pathology and oligodendroglial dysfunction may be beneficial for HD.Agency for Science, Technology and Research (A*STAR)Accepted versionWe thank members of the M.A.P. laboratory for helpful discussions and comments. C.F.B. is supported by a Singapore International Graduate Award from the Agency for Science, Technology and Research (A*STAR). M.A.P. is supported by grants from A*STAR and the National University of Singapore

A retrospective cohort study of risk factors for mortality among nursing homes exposed to COVID-19 in Spain

Long-term care (LTC) facilities have shown remarkably high mortality rates during the coronavirus disease 2019 (COVID-19) outbreak in many countries1, and different risk factors for mortality have been identified in this setting2–5. Using facilities as the unit of analysis, we investigated multiple variables covering facility characteristics and socioeconomic characteristics of the geographic location to identify risk factors for excess mortality from a comprehensive perspective. Furthermore, we used a clustering approach to detect patterns in datasets and generate hypotheses regarding potential relationships between types of nursing homes and mortality trends. Our retrospective analysis included 167 nursing homes providing LTC to 8,716 residents during the COVID-19 outbreak in Catalonia (northeast Spain). According to multiple regression analysis, COVID-19-related and overall mortality at the facility level were significantly associated with a higher percentage of patients with complex diseases, lower scores on pandemic preparedness measures and higher population incidence of COVID-19 in the surrounding population. When grouping nursing homes into eight clusters based on common features, we found higher mortality rates in four clusters, mainly characterized by a higher proportion of residents with complex chronic conditions or advanced diseases, lower scores on pandemic preparedness, being located in rural areas and larger capacity, respectively

ARHGEF7 (BETA-PIX) Acts as Guanine Nucleotide Exchange Factor for Leucine-Rich Repeat Kinase 2

Background: Mutations within the leucine-rich repeat kinase 2 (LRRK2) gene are a common cause of familial and sporadic Parkinson’s disease. The multidomain protein LRRK2 exhibits overall low GTPase and kinase activity in vitro. Methodology/Principal Findings: Here, we show that the rho guanine nucleotide exchange factor ARHGEF7 and the small GTPase CDC42 are interacting with LRRK2 in vitro and in vivo. GTPase activity of full-length LRRK2 increases in the presence of recombinant ARHGEF7. Interestingly, LRRK2 phosphorylates ARHGEF7 in vitro at previously unknown phosphorylation sites. We provide evidence that ARHGEF7 might act as a guanine nucleotide exchange factor for LRRK2 and that R1441C mutant LRRK2 with reduced GTP hydrolysis activity also shows reduced binding to ARHGEF7. Conclusions/Significance: Downstream effects of phosphorylation of ARHGEF7 through LRRK2 could be (i) a feedback control mechanism for LRRK2 activity as well as (ii) an impact of LRRK2 on actin cytoskeleton regulation. A newly identified familial mutation N1437S, localized within the GTPase domain of LRRK2, further underlines the importance of the GTPas

Ermin deficiency leads to compromised myelin, inflammatory milieu, and susceptibility to demyelinating insult

Ermin is an actin-binding protein found almost exclusively in the central nervous system (CNS) as a component of myelin sheaths. Although Ermin has been predicted to play a role in the formation and stability of myelin sheaths, this has not been directly examined in vivo. Here, we show that Ermin is essential for myelin sheath integrity and normal saltatory conduction. Loss of Ermin in mice caused de-compacted and fragmented myelin sheaths and led to slower conduction along with progressive neurological deficits. RNA sequencing of the corpus callosum, the largest white matter structure in the CNS, pointed to inflammatory activation in aged Ermin-deficient mice, which was corroborated by increased levels of microgliosis and astrogliosis. The inflammatory milieu and myelin abnormalities were further associated with increased susceptibility to immune-mediated demyelination insult in Ermin knockout mice. Supporting a possible role of Ermin deficiency in inflammatory white matter disorders, a rare inactivating mutation in the ERMN gene was identified in multiple sclerosis patients. Our findings demonstrate a critical role for Ermin in maintaining myelin integrity. Given its near-exclusive expression in myelinating oligodendrocytes, Ermin deficiency represents a compelling “inside-out” model of inflammatory dysmyelination and may offer a new paradigm for the development of myelin stability-targeted therapies

Management and Outcome of Cardiac and Endovascular Cystic Echinococcosis

Cardiac and vascular involvement are infrequent in classical cystic echinococcosis (CE), but when they occur they tend to present earlier and are associated with complications that may be life threatening. Cardiovascular CE usually requires complex surgery, so in low-income countries the outcome is frequently fatal. This case series describes the characteristics of cardiovascular CE in patients diagnosed and treated at a Tropical Medicine & Clinical Parasitology Center in Spain. A retrospective case series of 11 patients with cardiac and/or endovascular CE, followed-up over a period of 15 years (1995–2009) is reported. The main clinical manifestations included thoracic pain or dyspnea, although 2 patients were asymptomatic. The clinical picture and complications vary according to cyst location. Isolated cardiac CE may be cured after surgery, while endovascular extracardiac involvement is associated with severe chronic complications. CE should be included in the differential diagnosis of cardiovascular disease in patients from endemic areas. CE is a neglected disease and further studies are necessary in order to make more definite management recommendations for this rare and severe form of the disease. The authors propose a general approach based on cyst location: exclusively cardiac, endovascular or both

Clustering COVID-19 ARDS patients through the first days of ICU admission. An analysis of the CIBERESUCICOVID Cohort

Background Acute respiratory distress syndrome (ARDS) can be classified into sub-phenotypes according to different inflammatory/clinical status. Prognostic enrichment was achieved by grouping patients into hypoinflammatory or hyperinflammatory sub-phenotypes, even though the time of analysis may change the classification according to treatment response or disease evolution. We aimed to evaluate when patients can be clustered in more than 1 group, and how they may change the clustering of patients using data of baseline or day 3, and the prognosis of patients according to their evolution by changing or not the cluster.Methods Multicenter, observational prospective, and retrospective study of patients admitted due to ARDS related to COVID-19 infection in Spain. Patients were grouped according to a clustering mixed-type data algorithm (k-prototypes) using continuous and categorical readily available variables at baseline and day 3.Results Of 6205 patients, 3743 (60%) were included in the study. According to silhouette analysis, patients were grouped in two clusters. At baseline, 1402 (37%) patients were included in cluster 1 and 2341(63%) in cluster 2. On day 3, 1557(42%) patients were included in cluster 1 and 2086 (57%) in cluster 2. The patients included in cluster 2 were older and more frequently hypertensive and had a higher prevalence of shock, organ dysfunction, inflammatory biomarkers, and worst respiratory indexes at both time points. The 90-day mortality was higher in cluster 2 at both clustering processes (43.8% [n = 1025] versus 27.3% [n = 383] at baseline, and 49% [n = 1023] versus 20.6% [n = 321] on day 3). Four hundred and fifty-eight (33%) patients clustered in the first group were clustered in the second group on day 3. In contrast, 638 (27%) patients clustered in the second group were clustered in the first group on day 3.Conclusions During the first days, patients can be clustered into two groups and the process of clustering patients may change as they continue to evolve. This means that despite a vast majority of patients remaining in the same cluster, a minority reaching 33% of patients analyzed may be re-categorized into different clusters based on their progress. Such changes can significantly impact their prognosis

Epidemiological trends of HIV/HCV coinfection in Spain, 2015-2019

Altres ajuts: Spanish AIDS Research Network; European Funding for Regional Development (FEDER).Objectives: We assessed the prevalence of anti-hepatitis C virus (HCV) antibodies and active HCV infection (HCV-RNA-positive) in people living with HIV (PLWH) in Spain in 2019 and compared the results with those of four similar studies performed during 2015-2018. Methods: The study was performed in 41 centres. Sample size was estimated for an accuracy of 1%. Patients were selected by random sampling with proportional allocation. Results: The reference population comprised 41 973 PLWH, and the sample size was 1325. HCV serostatus was known in 1316 PLWH (99.3%), of whom 376 (28.6%) were HCV antibody (Ab)-positive (78.7% were prior injection drug users); 29 were HCV-RNA-positive (2.2%). Of the 29 HCV-RNA-positive PLWH, infection was chronic in 24, it was acute/recent in one, and it was of unknown duration in four. Cirrhosis was present in 71 (5.4%) PLWH overall, three (10.3%) HCV-RNA-positive patients and 68 (23.4%) of those who cleared HCV after anti-HCV therapy (p = 0.04). The prevalence of anti-HCV antibodies decreased steadily from 37.7% in 2015 to 28.6% in 2019 (p < 0.001); the prevalence of active HCV infection decreased from 22.1% in 2015 to 2.2% in 2019 (p < 0.001). Uptake of anti-HCV treatment increased from 53.9% in 2015 to 95.0% in 2019 (p < 0.001). Conclusions: In Spain, the prevalence of active HCV infection among PLWH at the end of 2019 was 2.2%, i.e. 90.0% lower than in 2015. Increased exposure to DAAs was probably the main reason for this sharp reduction. Despite the high coverage of treatment with direct-acting antiviral agents, HCV-related cirrhosis remains significant in this population