A blood atlas of COVID-19 defines hallmarks of disease severity and specificity.

Treatment of severe COVID-19 is currently limited by clinical heterogeneity and incomplete description of specific immune biomarkers. We present here a comprehensive multi-omic blood atlas for patients with varying COVID-19 severity in an integrated comparison with influenza and sepsis patients versus healthy volunteers. We identify immune signatures and correlates of host response. Hallmarks of disease severity involved cells, their inflammatory mediators and networks, including progenitor cells and specific myeloid and lymphocyte subsets, features of the immune repertoire, acute phase response, metabolism, and coagulation. Persisting immune activation involving AP-1/p38MAPK was a specific feature of COVID-19. The plasma proteome enabled sub-phenotyping into patient clusters, predictive of severity and outcome. Systems-based integrative analyses including tensor and matrix decomposition of all modalities revealed feature groupings linked with severity and specificity compared to influenza and sepsis. Our approach and blood atlas will support future drug development, clinical trial design, and personalized medicine approaches for COVID-19

Abstracts from the 20th International Symposium on Signal Transduction at the Blood-Brain Barriers

https://deepblue.lib.umich.edu/bitstream/2027.42/138963/1/12987_2017_Article_71.pd

Selective permeabilisation of the blood-brain barrier during brain metastasis via TNFR1

The presence of an intact, impermeable blood-brain barrier (BBB) during the early stages of metastatic colonisation significantly limits early detection and effective treatment of brain metastasis. Systemic tumour necrosis factor (TNF) administration transiently permeabilises the metastasis-associated vasculature, whilst retaining the integrity of the surrounding the BBB. This approach enables both the enhanced detection of metastatic colonies with contrast-enhanced MRI and the improved delivery of therapeutically relevant molecules to the tumour site. The aim of this thesis was to unravel the mechanism underlying the TNF-induced BBB breakdown. TNFR1, but not TNFR2, is upregulated on tumour-associated vasculature in experimental models, human brain metastasis resections and endothelial cells co-cultured with metastatic tumour cells (breast, lung or melanoma) or stimulated with relevant tumour cell conditioned media. Treatment of an endothelial monolayer with either TNF or a TNR1-selective mutein increased permeability, which was eliminated in TNFR1-silenced endothelial cells stimulated with TNF. TNFR2 silencing did not alter TNF-induced endothelial permeability. In vitro studies revealed that the blockade of the Ras/PI3K/Akt/mTOR signalling cascade, alongside components of the RhoGTPase family and NFκΒ pathway prevented the TNF-induced permeabilisation of the brain endothelium. On the contrary, targeting of the MAPK pathways had no effect on TNF-induced permeabilisation. The results of this study suggest that TNF-induced BBB permeabilisation is TNFR1-mediated and involves activation of the Ras/PI3K, the Ras/ RhoGTPases and NFκΒ pathways. These findings support the concept that TNFR1-targeted agents may provide a sensitive and specific means to selectively and transiently modulate the BBB at sites of brain micrometastasis.</p

Modelling the pathology and treatment of cardiac fibrosis in vascularised atrial and ventricular cardiac microtissues

Introduction: Recent advances in human cardiac 3D approaches have yielded progressively more complex and physiologically relevant culture systems. However, their application in the study of complex pathological processes, such as inflammation and fibrosis, and their utility as models for drug development have been thus far limited. Methods: In this work, we report the development of chamber-specific, vascularised human induced pluripotent stem cell-derived cardiac microtissues, which allow for the multi-parametric assessment of cardiac fibrosis. Results: We demonstrate the generation of a robust vascular system in the microtissues composed of endothelial cells, fibroblasts and atrial or ventricular cardiomyocytes that exhibit gene expression signatures, architectural, and electrophysiological resemblance to in vivo-derived anatomical cardiac tissues. Following pro-fibrotic stimulation using TGFβ, cardiac microtissues recapitulated hallmarks of cardiac fibrosis, including myofibroblast activation and collagen deposition. A study of Ca2+ dynamics in fibrotic microtissues using optical mapping revealed prolonged Ca2+ decay, reflecting cardiomyocyte dysfunction, which is linked to the severity of fibrosis. This phenotype could be reversed by TGFβ receptor inhibition or by using the BET bromodomain inhibitor, JQ1. Discussion: In conclusion, we present a novel methodology for the generation of chamber-specific cardiac microtissues that is highly scalable and allows for the multi-parametric assessment of cardiac remodelling and pharmacological screening

In utero origin of myelofibrosis presenting in adult monozygotic twins

The latency between acquisition of an initiating somatic driver mutation by a single-cell and clinical presentation with cancer is largely unknown. We describe a remarkable case of monozygotic twins presenting with CALR mutation-positive myeloproliferative neoplasms (MPNs) (aged 37 and 38 years), with a clinical phenotype of primary myelofibrosis. The CALR mutation was absent in T cells and dermal fibroblasts, confirming somatic acquisition. Whole-genome sequencing lineage tracing revealed a common clonal origin of the CALR-mutant MPN clone, which occurred in utero followed by twin-to-twin transplacental transmission and subsequent similar disease latency. Index sorting and single-colony genotyping revealed phenotypic hematopoietic stem cells (HSCs) as the likely MPN-propagating cell. Furthermore, neonatal blood spot analysis confirmed in utero origin of the JAK2V617F mutation in a patient presenting with polycythemia vera (aged 34 years). These findings provide a unique window into the prolonged evolutionary dynamics of MPNs and fitness advantage exerted by MPN-associated driver mutations in HSCs