The rockefeller university

Breaking the anterior-posterior symmetry in mammals occurs at gastrulation. Much of the signalling network underlying this process has been elucidated in the mouse; however, there is no direct molecular evidence of events driving axis formation in humans. Here, we use human embryonic stem cells to generate an in vitro three-dimensional model of a human epiblast whose size, cell polarity and gene expression are similar to a day 10 human epiblast. A defined dose of BMP4 spontaneously breaks axial symmetry, and induces markers of the primitive streak and epithelial-to-mesenchymal transition. We show that WNT signalling and its inhibitor DKK1 play key roles in this process downstream of BMP4. Our work demonstrates that a model human epiblast can break axial symmetry despite the absence of asymmetry in the initial signal and of extra-embryonic tissues or maternal cues. Our three-dimensional model is an assay for the molecular events underlying human axial symmetry breaking.

Purpose: China recently commenced several pre-exposure prophylaxis (PrEP) projects, but little work has characterized potential users. This study describes awareness of, intention to use, and uptake of PrEP in a sample of men who have sex with men (MSM), a key population experiencing high rates of HIV in China. Methods: Through a cross-sectional survey administered to 708 MSM in four cities, we mapped respondents onto a Motivational PrEP Cascade. We conducted bivariable and multivariable analysis to examine factors associated with progression through the Cascade. Results: Among 45.6% of MSM who were PrEP eligible, 36% were in Contemplation, 9% were in PrEParation, 2% were in PrEP Action and Initiation, and none reached Maintenance and Adherence. We found no association between individual risk factors and progression through the Cascade. In multivariable analysis, friends' positive attitudes toward PrEP, more frequent sexually transmitted infection testing, and higher scores on the perceived PrEP benefits scale were positively associated with entering PrEP Contemplation. Having higher condom use self-efficacy was associated with decreased odds of entering PrEP Contemplation. Having sex with men and women in the past 6 months, having heard of PrEP from medical providers, and knowing a PrEP user were positively associated with entering PrEParation. Conclusion: We found a high proportion of MSM who were PrEP eligible and identified several intervention targets to prepare for PrEP introduction in China: community education to increase accurate knowledge, gain-framed messaging for PrEP and sexual health, and provider trainings to build MSM-competent services that can support shared decision-making for PrEP initiation.

The 3rd Annual Symposium on Hidradenitis Suppurativa Advances (SHSA) took place on 12-14 October 2018 at the Women's College Hospital in Toronto, Ontario, Canada. This symposium was a joint meeting of the Hidradenitis Suppurativa Foundation (HSF) founded in the USA and the Canadian Hidradenitis Suppurativa Foundation (CHSF). This cross-disciplinary meeting with experts from around the world was an opportunity to discuss the most recent advances in the study of hidradenitis suppurativa pathogenesis, epidemiology, classification, scoring systems, radiologic diagnosis, treatment approaches and psychologic assessment. Two special sessions this year were HS as a systemic disease and HS management guidelines. There were focused workshops on wound healing and ultrasound. There were two sessions primarily for patients and their families in the HS School programme: One workshop focused on mindfulness, and the second involved discussion among clinicians and patients about various disease aspects and the latest management. To facilitate networking between clinical and research experts and those early in their career, a mentoring breakfast was held.

Twin CMG complexes are assembled head-to-head around duplex DNA at

The eukaryotic replicative helicase CMG is a closed ring around double-stranded (ds)DNA at origins yet must transition to single-stranded (ss)DNA for helicase action. CMG must also handle repair intermediates, such as reversed forks that lack ssDNA. Here, using correlative single-molecule fluorescence and force microscopy, we show that CMG harbors a ssDNA gate that enables transitions between ss and dsDNA. When coupled to DNA polymerase, CMG remains on ssDNA, but when uncoupled, CMG employs this gate to traverse forked junctions onto dsDNA. Surprisingly, CMG undergoes rapid diffusion on dsDNA and can transition back onto ssDNA to nucleate a functional replisome. The gate-distinct from that between Mcm2/5 used for origin loading-is intrinsic to CMG; however, Mcm10 promotes strand passage by enhancing the affinity of CMG to DNA. This gating process may explain the dsDNA-to-ssDNA transition of CMG at origins and help preserve CMG on dsDNA during fork repair.

Mutations in coiled-coil-helix-coiled-coil-helix domain containing 10 (CHCHD10), a mitochondrial protein of unknown function, cause a disease spectrum with clinical features of motor neuron disease, dementia, myopathy and cardiomyopathy. To investigate the pathogenic mechanisms of CHCHD10, we generated mutant knock-in mice harboring the mouse-equivalent of a disease-associated human S59L mutation, S55L in the endogenous mouse gene. CHCHD10(S55L) mice develop progressive motor deficits, myopathy, cardiomyopathy and accelerated mortality. Critically, CHCHD10 accumulates in aggregates with its paralog CHCHD2 specifically in affected tissues of CHCHD10(S55L) mice, leading to aberrant organelle morphology and function. Aggregates induce a potent mitochondrial integrated stress response (mtISR) through mTORC1 activation, with elevation of stress-induced transcription factors, secretion of myokines, upregulated serine and one-carbon metabolism, and downregulation of respiratory chain enzymes. Conversely, CHCHD10 ablation does not induce disease pathology or activate the mtISR, indicating that CHCHD10(S55L)-dependent disease pathology is not caused by loss-of-function. Overall, CHCHD10(S55L) mice recapitulate crucial aspects of human disease and reveal a novel toxic gain-of-function mechanism through maladaptive mtISR and metabolic dysregulation.

Multiple areas within the reticular activating system (RAS) can hasten awakening from sleep or light planes of anesthesia. However, stimulation in individual sites has shown limited recovery from deep global suppression of brain activity, such as coma. Here we identify a subset of RAS neurons within the anterior portion of nucleus gigantocellularis (aNGC) capable of producing a high degree of awakening represented by a broad high frequency cortical reactivation associated with organized movements and behavioral reactivity to the environment from two different models of deep pharmacologically-induced coma (PIC): isoflurane (1.25%-1.5%) and induced hypoglycemic coma. Activating aNGC neurons triggered awakening by recruiting cholinergic, noradrenergic, and glutamatergic arousal pathways. In summary, we identify an evolutionarily conserved population of RAS neurons, which broadly restore cerebral cortical activation and motor behavior in rodents through the coordinated activation of multiple arousal-promoting circuits.

Purpose of ReviewIn this review, we summarize the recent literature regarding the incidence and treatment of seizures arising after ischemic and hemorrhagic strokes. Additionally, we identify open questions in guidelines and standard clinical care to aid future studies aiming to improve management of seizures in post-stroke patients.Recent FindingsStudies demonstrate an increasing prevalence of seizures following strokes, probably a consequence of advances in post-stroke management and expanding use of continuous EEG monitoring. Post-stroke seizures are associated with longer hospitalization and increased mortality; therefore, prevention and timely treatment of seizures are important. The standard of care is to treat recurrent seizures with anti-epileptic drugs (AEDs) regardless of the etiology. However, there are no established guidelines currently for prophylactic use of AEDs following a stroke.SummaryThe prevalence of post-stroke seizures is increasing. Further studies are needed to determine the risk factors for recurrent seizures and epilepsy after strokes and optimal treatment strategies.

To define the cell populations that drive joint inflammation in rheumatoid arthritis (RA), we applied single-cell RNA sequencing (scRNA-seq), mass cytometry, bulk RNA sequencing (RNA-seq) and flow cytometry to Tcells, B cells, monocytes, and fibroblasts from 51 samples of synovial tissue from patients with RA or osteoarthritis (OA). Utilizing an integrated strategy based on canonical correlation analysis of 5,265 scRNA-seq profiles, we identified 18 unique cell populations. Combining mass cytometry and transcriptomics revealed cell states expanded in RA synovia: THY1(CD90)(+)HLA-DRA(hi) sublining fibroblasts, IL1B(+) pro-inflammatory monocytes, ITGAX(+)TBX21(+) autoimmune-associated B cells and PDCD1(+) peripheral helper T (T-PH) cells and follicular helper T (T-FH) cells. We defined distinct subsets of CD8(+)Tcells characterized by GZMIK(+), GZMB(+), and GNLY(+) phenotypes. We mapped inflammatory mediators to their source cell populations; for example, we attributed 1L6 expression to THYl(+)HLA-DRA(hi )fibroblasts and IL1B production to pro-inflammatory monocytes. These populations are potentially key mediators of RA pathogenesis.

BackgroundBiomedical interventions such as antiretroviral therapy (ART)