Heterogeneity in vascular smooth muscle cell gene expression and its association with clonal proliferation in models of vascular disease

Deregulation of vascular smooth muscle cell (VSMC) phenotypic switching is implicated in vascular disease development and VSMCs produce the majority of cells in late-stage atherosclerotic plaques. However, VSMC accumulation in mouse models of vascular disease arises from clonal expansion of very few medial cells. The source of these cells and mechanism of their selection are unknown. Hypothesising that VSMCs which expand in disease would be distinctive within the healthy population, single cell RNA sequencing (scRNA-seq) was combined with mouse VSMC-specific lineage tracing to profile VSMC transcriptomes from healthy aorta and two in vivo disease models (CL – carotid ligation and HFD – high-fat diet-induced atherosclerosis). This identified VSMCs expressing stem cell antigen-1 (Sca1), which lacked expression of conventional VSMC markers, but were also distinct from adventitial and endothelial cell profiles. Induction of Sca1 was evident in phenotypically switched VSMCs in vitro and in both in vivo disease models. Notably, Sca1+ VSMCs were a rare subset in the healthy aorta, but more prevalent in the two disease datasets and expressed an activated, responsive gene signature in all three environments. This gene signature contains known regulators of plaque progression; suggestive that they may be candidates for those cells selectively proliferating in disease. Focusing on VSMCs from CL, the scRNA-seq dataset lacked discrete clusters of gene expression. Instead a transition in expression profiles could be seen, allowing for cells to be mapped onto a linear trajectory, using an unbiased approach. This trajectory showed contractile marker downregulation over pseudotime, corresponding to increased expression of Sca1 and proliferation marker Ki67. Moreover, Ki67+Sca1+ VSMCs were identified post-CL via flow cytometry, indicating that Sca1+ VSMCs indeed expand in disease. Investigation of candidate genes with differential expression across this pseudotime revealed enrichment for VSMC activation and disease-relevant gene ontology pathways. Further disease relevance of these candidates was highlighted using immunostaining of mouse and human plaque sections and comparison to other scRNA-seq datasets. Finally, a lineage traced tissue explant model was developed to study clonal VSMC proliferation in vitro. Traditional dissociated primary cell culture causes spontaneous VSMC phenotypic switching and general proliferation, which is not representative of the in vivo VSMC response. The explant model presented here maintains cell-cell and cell-extracellular matrix contact, resulting in limited proliferation of VSMCs and formation of monoclonal patches of VSMCs, comparable to those seen in vivo. Additionally, the model replicated published observations of differences in proliferation of VSMCs derived from two distinct aortic regions and increased proliferation with growth factor treatment. Lentiviral transduction of the explanted VSMCs allowed for genetic manipulation, providing a platform to test the influence of individual genes on VSMC clonal expansion. In summary, this work identified a rare Sca1+ VSMC population which may represent a source of clonally expanding VSMCs. A comprehensive resource of transcriptional data from healthy and disease associated VSMCs has been generated and interrogation revealed commonality in activated Sca1+ VSMC expression profiles. Further investigation demonstrated a trajectory of gene expression, implicating many disease-relevant genes in VSMC activation. When combined with the in vitro lineage labelled model of VSMC proliferation, this provides a basis for identification and screening of genes involved in clonal expansion, with the ultimate aim to isolate or selectively target specific detrimental VSMC subpopulations.BHF grant code FS/14/59/3128

Social factors in dementia praecox

Thesis (M.A.)--University of Kansas, Sociology, 1930

Toward a transformed system to address child abuse and family violence in New Zealand

Executive Summary Introduction The Glenn Inquiry (TGI) has contracted Institute of Environmental Science and Research Limited (ESR) to bring together the relevant experience and expertise to collaboratively model a transformed system to address child abuse and neglect (CAN) and family violence (FV) in New Zealand. Our approach We have treated the task of reducing FV and CAN as a ‘wicked problem’1; that is, reducing FV and CAN is a problem that cannot be solved once and for all, and is not a matter of simply applying expert knowledge. The methods used in this project have been chosen because they are appropriate for working with wicked problems: stakeholder engagement, systems thinking and inter-disciplinary analysis. In this report, we refer to both CAN and FV. We recognise that, for some purposes, dealing with CAN requires particular strategies and treatment; however, the purpose of this report is to develop a transformed system that will reduce both CAN and other forms of FV. While the underlying causes of CAN and other FV may be considered independently, and some responses to each form of abuse will need to be particular, this report proposes a wider system of responses that will enable targeted interventions for each form of abuse. We use the term ‘family violence’ in this report in the sense it has come to be understood in Aotearoa, and is used in Te Rito: New Zealand Family Violence Prevention Strategy. In this use, FV includes intimate partner violence, child abuse and neglect, elder abuse, inter-sibling abuse and parental abuse. The project consisted of four work-streams: A review of the international and national literature on what would constitute a high performing system to address CAN and FV, including a review of New Zealand’s current approach with a focus on government legalisation, policies and initiatives; Qualitative modelling of the system dynamics associated with the existing way in which New Zealand has responded to CAN and FV; A secondary (sociological) analysis of suggestions for system improvement from the People’s Report; and, Developing a systemic model of a transformed system through collaborative workshops with sector experts

What are parents’ and children’s co-constructed views on mobile phone use and policies in school?

Increasing ownership of mobile phones by children increases pressure on schools to create mobile phone policies. This study investigated parents’ and children’s co-constructed views of mobile phone use at school. Nine parent and child (aged 10 to 11 years) dyads were interviewed. The data was analysed using Reflexive Thematic Analysis. Generally, parents and children held shared views of the importance of having phones to keep in contact alongside an awareness of the risks. Hearing the children’s and parents’ co-constructed views and solutions highlights the potential positive impact of their involvement in co-developing school mobile phone policies

A Shorter Form of the Work Extrinsic and Intrinsic Motivation Scale: Construction and Factorial Validation

While workplace mental health has attracted attention in many countries, work motivation remains under-researched. Research identified that work motivation is associated with many organisational positive outcomes including workplace mental health. One well-recognised measure is the Work Extrinsic and Intrinsic Motivation Scale (WEIMS). Conceptualised on the Self-Determination Theory, this 18-item scale examines six types of work motivation: Intrinsic Motivation, Integrated Regulation, Identified Regulation, Introjected Regulation, External Regulation, and Amotivation. WEIMS can be too long for busy people at work. Accordingly, we constructed and validated a shorter form of WEIMS (SWEIMS), comprising 12 items that evaluate the same six work motivation types. Data collected from two professional samples were analysed to construct and validate the factorial structure: 155 construction workers (138 males and 17 females, Age 40.28 ± 11.05) and 103 hospitality workers (47 males and 56 females, Age 28.2 ± 8.6 years). Correlation analyses and confirmatory factor analyses were performed. Two items from each type were selected based on the strength of correlations with the target WEIMS subscale. SWEIMS demonstrated adequate internal consistency (α ≧ 0.65), and strong correlations with the original version of WEIMS (r = 0.73) in both samples. SWEIMS confirmatory factor analysis replicated the six-factor model of the original SWEIMS. SWEIMS can be a reliable, valid, and user-friendly alternative to WEIMS

Disease-relevant transcriptional signatures identified in individual smooth muscle cells from healthy mouse vessels.

Vascular smooth muscle cells (VSMCs) show pronounced heterogeneity across and within vascular beds, with direct implications for their function in injury response and atherosclerosis. Here we combine single-cell transcriptomics with lineage tracing to examine VSMC heterogeneity in healthy mouse vessels. The transcriptional profiles of single VSMCs consistently reflect their region-specific developmental history and show heterogeneous expression of vascular disease-associated genes involved in inflammation, adhesion and migration. We detect a rare population of VSMC-lineage cells that express the multipotent progenitor marker Sca1, progressively downregulate contractile VSMC genes and upregulate genes associated with VSMC response to inflammation and growth factors. We find that Sca1 upregulation is a hallmark of VSMCs undergoing phenotypic switching in vitro and in vivo, and reveal an equivalent population of Sca1-positive VSMC-lineage cells in atherosclerotic plaques. Together, our analyses identify disease-relevant transcriptional signatures in VSMC-lineage cells in healthy blood vessels, with implications for disease susceptibility, diagnosis and prevention.BH

Vascular Smooth Muscle Cell Plasticity and Autophagy in Dissecting Aortic Aneurysms.

Objective- Recent studies suggested the occurrence of phenotypic switching of vascular smooth muscle cells (VSMCs) during the development of aortic aneurysm (AA). However, lineage-tracing studies are still lacking, and the behavior of VSMCs during the formation of dissecting AA is poorly understood. Approach and Results- We used multicolor lineage tracing of VSMCs to track their fate after injury in murine models of Ang II (angiotensin II)-induced dissecting AA. We also addressed the direct impact of autophagy on the response of VSMCs to AA dissection. Finally, we studied the relevance of these processes to human AAs. Here, we show that a subset of medial VSMCs undergoes clonal expansion and that VSMC outgrowths are observed in the adventitia and borders of the false channel during Ang II-induced development of dissecting AA. The clonally expanded VSMCs undergo phenotypic switching with downregulation of VSMC differentiation markers and upregulation of phagocytic markers, indicative of functional changes. In particular, autophagy and endoplasmic reticulum stress responses are activated in the injured VSMCs. Loss of autophagy in VSMCs through deletion of autophagy protein 5 gene ( Atg5) increases the susceptibility of VSMCs to death, enhances endoplasmic reticulum stress activation, and promotes IRE (inositol-requiring enzyme) 1α-dependent VSMC inflammation. These alterations culminate in increased severity of aortic disease and higher incidence of fatal AA dissection in mice with VSMC-restricted deletion of Atg5. We also report increased expression of autophagy and endoplasmic reticulum stress markers in VSMCs of human dissecting AAs. Conclusions- VSMCs undergo clonal expansion and phenotypic switching in Ang II-induced dissecting AAs in mice. We also identify a critical role for autophagy in regulating VSMC death and endoplasmic reticulum stress-dependent inflammation with important consequences for aortic wall homeostasis and repair

Brain Imaging With Portable Low-Field MRI

The advent of portable, low-field MRI (LF-MRI) heralds new opportunities in neuroimaging. Low power requirements and transportability have enabled scanning outside the controlled environment of a conventional MRI suite, enhancing access to neuroimaging for indications that are not well suited to existing technologies. Maximizing the information extracted from the reduced signal-to-noise ratio of LF-MRI is crucial to developing clinically useful diagnostic images. Progress in electromagnetic noise cancellation and machine learning reconstruction algorithms from sparse k-space data as well as new approaches to image enhancement have now enabled these advancements. Coupling technological innovation with bedside imaging creates new prospects in visualizing the healthy brain and detecting acute and chronic pathological changes. Ongoing development of hardware, improvements in pulse sequences and image reconstruction, and validation of clinical utility will continue to accelerate this field. As further innovation occurs, portable LF-MRI will facilitate the democratization of MRI and create new applications not previously feasible with conventional systems