3,367 research outputs found
An examination of the verbal behaviour of intergroup discrimination
This thesis examined relationships between psychological flexibility, psychological inflexibility, prejudicial attitudes, and dehumanization across three cross-sectional studies with an additional proposed experimental study. Psychological flexibility refers to mindful attention to the present moment, willing acceptance of private experiences, and engaging in behaviours congruent with one’s freely chosen values. Inflexibility, on the other hand, indicates a tendency to suppress unwanted thoughts and emotions, entanglement with one’s thoughts, and rigid behavioural patterns. Study 1 found limited correlations between inflexibility and sexism, racism, homonegativity, and dehumanization. Study 2 demonstrated more consistent positive associations between inflexibility and prejudice. And Study 3 controlled for right-wing authoritarianism and social dominance orientation, finding inflexibility predicted hostile sexism and racism beyond these factors. While showing some relationships, particularly with sexism and racism, psychological inflexibility did not consistently correlate with varied prejudices across studies.
The proposed randomized controlled trial aims to evaluate an Acceptance and Commitment Therapy intervention to reduce sexism through enhanced psychological flexibility. Overall, findings provide mixed support for the utility of flexibility-based skills in addressing complex societal prejudices. Research should continue examining flexibility integrated with socio-cultural approaches to promote equity
Pathophysiological role and therapeutic potential of extracellular vesicles in cancer
Extracellular vesicles (EVs) are nanosized lipid bilayer vesicles that are endogenously
generated through various biogenesis pathways within most cellular entities. Subsequently,
they are released into the extracellular milieu to facilitate intercellular communication. They
are composed of diverse bioactive molecules with important roles in physiological and
pathological states. Over the past few decades, the therapeutic potential of EVs has garnered
significant interest in the drug delivery field. However, deepened understanding of EV biology
and further technological advances are needed to bridge the gap between research and clinical
translation. In this thesis, we address these challenges and investigate EVs as novel biomedical
agents.
EVs are crucial components of physiological processes and disease development. Sensitive
visualisation techniques are needed to better understand their function as therapeutic agents. In
paper I, a bioluminescent labelling system was developed to track EVs in vitro and in vivo. The
system uses genetic modifications to enable the encapsulation of sensitive luciferase-variants
in EVs. The system was used in vivo to enable highly sensitive detection of EV distribution
pattern. Exogenously administered EVs were found to rapidly distribute within different organs,
with a preference for the spleen, lung, and liver.
In addition to endogenously engineered EVs for in vivo tracking, exogenously engineered EVs
can be utilised as promising drug delivery platforms. However, cargo loading is often
insufficient, requiring improved EV loading approaches. In paper II, we developed an optimised
cargo loading method using electroporation. An optimised protocol was designed to load EVs
with doxorubicin, which increased cargo loading, EV recovery, and drug potency by 190-fold
over free doxorubicin.
Owing to their potential to cross biological barriers, transport bioactive cargo, and targetability,
EVs can be exploited as delivery vehicles for targeting of therapeutics. EVs were used as
delivery vectors in paper III by coating their surfaces with an Fc domain-specific antibodybinding
moiety. These Fc-EVs were then decorated with various IgG antibodies and targeted to
cells of interest. In vitro and in vivo antibody targeting studies showed the broad potential of
this technology for cancer therapy. The platform efficiently targeted EVs to cancer cells,
including HER2 and PD-L1 positive cells. As proof of concept, Fc-EVs with PD-L1 antibody
accumulate in tumour tissue and, when loaded with doxorubicin, reduce tumour burden, and
increase survival in melanoma-bearing mice.
Despite significant EV engineering advances, we have a limited understanding of the biology
of tumour-derived extracellular vesicles (tEVs). In paper IV, we investigated the role of in vitrogenerated
melanoma-derived EVs as indirect communicators in tumour-induced
haematopoiesis dysregulation. The tEVs, which contain high levels of angiogenic factors like
VEGF, osteopontin, and tissue factor, were found to cause splenomegaly, extramedullary
haematopoiesis, expansion of splenic immature erythroid progenitors, reduced bone marrow
cellularity, medullary expansion of granulocytic myeloid suppressor cells, and anaemia in
syngeneic mice. These findings suggest that tEVs dysregulate haematopoiesis during the
immune escape phase of cancer immunoediting, making them potential targets for overcoming
immune evasion and restoring normal haematopoiesis.
To summarise, the tools generated in this thesis, including the ability to detect EVs in vivo,
effective cargo loading, display antibody binding moieties on EV surfaces for targeting, and
understanding the pathophysiological role of tEVs, contribute to the advancement of EVs for
biomedical purposes, and clinical translation down the line
Stony coral tissue loss disease: a review of emergence, impacts, etiology, diagnostics, and intervention
Stony coral tissue loss disease (SCTLD) is destructive and poses a significant threat to Caribbean coral reef ecosystems. Characterized by the acute loss of coral tissue, SCTLD has impacted over 22 stony coral species across the Caribbean region, leading to visible declines in reef health. Based on the duration, lethality, host range, and spread of this disease, SCTLD is considered the most devastating coral disease outbreak ever recorded. Researchers are actively investigating the cause and transmission of SCTLD, but the exact mechanisms, triggers, and etiological agent(s) remain elusive. If left unchecked, SCTLD could have profound implications for the health and resilience of coral reefs worldwide. To summarize what is known about this disease and identify potential knowledge gaps, this review provides a holistic overview of SCTLD research, including species susceptibility, disease transmission, ecological impacts, etiology, diagnostic tools, host defense mechanisms, and treatments. Additionally, future research avenues are highlighted, which are also relevant for other coral diseases. As SCTLD continues to spread, collaborative efforts are necessary to develop effective strategies for mitigating its impacts on critical coral reef ecosystems. These collaborative efforts need to include researchers from diverse backgrounds and underrepresented groups to provide additional perspectives for a disease that requires creative and urgent solutions
Analytical validation of innovative magneto-inertial outcomes: a controlled environment study.
peer reviewe
Managing risks and harms associated with the use of anabolic steroids
Background: People using AAS may adopt a range of strategies to prevent and treat adverse health conditions potentially associated with the use of these substances (AAS-HC). These strategies include seeking support from physicians, using the needle and syringe exchange programme (NSP) and seeking support from informal sources such as coaches and online forums. The process of identifying risks and harms, adopting and modifying health-related strategies is similar to the methods of risk-management employed in other fields of human activity. This approach recognises the importance of the informal body of knowledge produced by decades of AAS-related folk-pharmacology and seeks to understand harm-reduction from the users’ perspective.Objectives: The primary objective of this thesis is to investigate the strategies adopted by people using AAS to prevent and treat AAS-HC. Secondary objectives include to explore the factors associated with the adoption of health strategies and the occurrence of AAS-HC, as well as the barriers and facilitators experienced by AAS users when accessing health services and other sources of support.Methods: To achieve the objectives above, three work packages (WP) were produced as part of a mixed-methods research design. WP1 is a systematic review and meta-analysis of the prevalence of AAS users seeking support from physicians. WP2 is a cross-sectional online survey that identified AAS-HC, risk factors and health-related strategies adopted by AAS users in the UK. WP3 is a qualitative study based on in-depth interviews to discuss the experiences of AAS users and their risk-management strategies (RMS).Results: The estimated overall prevalence of AAS users seeking support from physicians is 37.1%. Higher prevalence rates were observed in studies from Australia (67.3%) and amongst clients of the NSP (54.1%), whilst the lowest was observed among adolescents (17.3%). The health conditions most commonly reported by the 883 participants of the online survey were insomnia (33.3%) and anxiety (32.2%). Most participants adopted preventive strategies such as having blood tests in the last 12 months (86.2%) and seeking a GP to treat AAS-HC (55.0%). Those who sought a GP for AAS-related information were 76% less likely to report an AAS-HC in the last 12 months. The interviews described AAS users’ RMS as a continuous process of awareness and behavioural changes. Participants described an extensive use of private health services and other sources of support to bypass the barriers experienced by AAS users engaging with the public health system.Conclusion: A large number of AAS users refrain from seeking support from physicians. Health professionals should be trained to recognise and manage the most common AAS-HC and help users improve their RMS. Further studies should investigate the efficacy of AAS-related RMS and the subpopulations of AAS users more likely to experience AAS-HC and less likely to engage with health services.<br/
The role of AD protective variant PLCγ2P522R in modulating microglia mediated clearance and synaptic pruning
PLCG2-P522R, a rare coding variant in the Phospholipase C gamma-2 (PLCG2) gene, has been found to be protective against late onset Alzheimer's disease (AD). Within the central nervous system, PLCγ2 is most abundantly expressed in microglia, and microglial mediated neuroinflammatory system has emerged as a major contributor to the molecular and phenotypic changes observed in the AD brain. However, the mechanism by which the P522R variant of PLCγ2 reduces AD pathology is still unknown. BV2 (mouse microglia) cells and human induced pluripotent stem-cells (hiPSC) derived microglia were used in this thesis work to evaluate the role of PLCγ2 in modifying various disease-relevant microglia functions. PLCγ2WT and PLCγ2P522R expression constructs were transfected into BV2 cells to examine the effects of PLCγ2 overexpression on various microglia functions including amyloid beta (Aβ) clearance and synaptic targeting, and various transcriptional changes linked to AD. hiPSCs were genome edited using CRISPR/Cas9 to generate both heterozygous and homozygous forms of the PLCG2_P522R variant in healthy controls. These hiPSC derived microglia were used to explore the effects of the PLCγ2P522R basal level on disease-relevant processes, such as microglial capacity to uptake Aβ and synapses. Microglia transcriptional changes were examined using targeted qPCR analysis to investigate changes in expression of key microglial genes. Mitochondrial function and calcium level changes were also investigated in these microglia cells to determine their metabolic fitness. In addition, the microglia were subjected to acute and chronic treatment of oligomeric Aβ to examine the impact of PLCγ2P522R on microglia's ability to respond to acute and chronic stress. As a result, the effects of Aβ oligomers on lysosomal biogenesis and phagocytic capacities of these microglia were examined further. As a result of PLCγ2 overexpression, Aβ uptake and other immune- provoking cargoes like zymosan were significantly increased. In contrast, the uptake of synaptosomes in BV2 cells overexpressing PLCγ2 was considerably reduced. Similarly, microglia generated from hiPSCs also showed enhanced clearance of Aβ and preservation of synapses by PLCγ2P522R variants. In the PLCγ2P522R microglia variants, the expression of multiple genes, including IL-10 and CX3CR1, as well as mitochondrial function, cytoplasmic calcium flux, and cellular motility were all increased. It was found that the protective effect of PLCγ2P522R was vitally dependent on 'allelic-dose', as homozygous cells displayed a lower preservation of synapse and a distinct gene expression profile compared to heterozygous cells. Similarly, microglia with the protective mutation PLCγ2P522R displayed higher inflammatory cytokine IL-1β level, and better response to acute treatment with Aβ oligomers. PLCγ2P522R appeared to resist the quiescence that was seen in WT microglia variants, by increasing cytokine production and lysosomal biogenesis. My findings suggest that the P522R variant in PLCγ2 increases microglia capacity to clear toxic aggregates such as Aβ while preserving synapses. Furthermore, my findings suggests that PLCγ2P522R contributes to greater microglial surveillance, as well as microglia priming towards a pro-inflammatory state, along with an increased capacity to adapt to growing energy demands. This, however, also shows the delicate balance of this system, as increasing the 'dosage' of PLCγ2P522R may result in diminished favourable benefits
Homeostasis in Immunity-Related Pupal Tissues of the Malaria Mosquito Anopheles gambiae and its regulation by the NF-kappaB-like Factor Rel2
Die Haut ist eine oft übersehene Komponente des angeborenen Immunsystems der Mücken. Die Haut der Mücke bildet eine physische Barriere, die die mikrobielle Homöostase aufrechterhält, das Eindringen von Toxinen wie Insektiziden verhindert und das Austrocknen verhindert. Die am meisten untersuchten Akteure des Immunsystems von Stechmücken sind das Fettgewebe und die Blutzellen, aber die Hauttalg-Fabriken, die Oenozyten, werden in Studien nur selten berücksichtigt.
Mückenpuppen haben aktiv funktionierende immunitätsbezogene Organe, einschließlich derjenigen, die Hautbarrieren produzieren. Ihre biologische Rolle in diesem Entwicklungsstadium ist kaum bekannt, aber der Übergang von der Puppen- zur Erwachsenenhaut und die Auffälligkeit der talgproduzierenden Zellen machen dieses Stadium zu einem vielversprechenden Entwicklungsstadium für die Untersuchung der Hautbildung.
Mit Hilfe der Transkriptomanalyse beschreiben wir die Rolle der Blutzellen bei der Entwicklung des chitinösen Teils der Insektenhaut, die Beteiligung des Fettkörpers an der Immunität und bestätigen die Rolle der talgproduzierenden Zellen im Lipidstoffwechsel. Darüber hinaus beschreiben wir talgsezernierende Zellen als einen bedeutenden Wirkungsort des NF-kappaB-ähnlichen IMD-Rel2-Pathway, in dem der Transkriptionsfaktor Rel2 die Retinoid-Homöostase reguliert. Schließlich bestätigen wir eine 100 Jahre alte Beobachtung, wonach sebumsezernierende Zellen der Stechmücke ihren Zellinhalt in einem Netzwerk von Vesikeln absondern. Wir beschreiben extrazelluläres Chromatin als Fracht in diesem Vesikelnetzwerk und sein antimikrobielles Potenzial.The skin is an often overlooked component of the mosquito's innate immune system. The mosquito skin provides a physical barrier that maintains microbial homeostasis, prevents the entry of toxins like insecticides, and avoids desiccation. The most studied players in the immune system of mosquitoes are the adipose tissue and blood cells, but studies rarely consider the skin sebum factories, oenocytes.
Mosquito pupae have actively functional immunity-related organs, including those producing skin barriers. Their biological roles at this developmental stage are poorly understood, but the pupae-to-adult metamorphic skin transition and the conspicuity of sebum-secreting cells make it a promising developmental stage to study skin formation.
We use transcriptomics to describe the role of blood cells in the development of the chitinous section of the insect skin, the involvement of the fat body in immunity, and confirm the lipid metabolism role of sebum-secreting cells. Furthermore, we describe sebum-secreting cells as a significant action site of the NF-kappaB-like IMD-Rel2 pathway where the transcription factor Rel2 regulates retinoid homeostasis. Finally, we confirm a 100-year-old observation of how mosquito sebum-secreting cells secrete their cellular contents in a network of vesicles. We describe extracellular chromatin as cargo inside this vesicle network and its antimicrobial potential
Phenotyping single-cell motility in microfluidic confinement.
This is the final version. Available from eLife Sciences Publications via the DOI in this record. Data availability:
New data and analysis codes generated as part of this study are available for download from Zenodo. The dataset includes all raw cell trajectories and motility states, as well as analysis and simulation codes.
The following data sets were generated:
Bentley SALaeverenz-Schlogelhofer HAnagnostidis VCammann JMazza MGGielen FWan KY (2022) Zenodo Dataset for: Phenotyping single-cell motility in microfluidic confinement. https://doi.org/10.5281/zenodo.7226288The movement trajectories of organisms serve as dynamic read-outs of their behaviour and physiology. For microorganisms this can be difficult to resolve due to their small size and fast movement. Here, we devise a novel droplet microfluidics assay to encapsulate single micron-sized algae inside closed arenas, enabling ultralong high-speed tracking of the same cell. Comparing two model species - Chlamydomonas reinhardtii (freshwater, 2 cilia), and Pyramimonas octopus (marine, 8 cilia), we detail their highly-stereotyped yet contrasting swimming behaviours and environmental interactions. By measuring the rates and probabilities with which cells transition between a trio of motility states (smooth-forward swimming, quiescence, tumbling or excitable backward swimming), we reconstruct the control network that underlies this gait switching dynamics. A simplified model of cell-roaming in circular confinement reproduces the observed long-term behaviours and spatial fluxes, including novel boundary circulation behaviour. Finally, we establish an assay in which pairs of droplets are fused on demand, one containing a trapped cell with another containing a chemical that perturbs cellular excitability, to reveal how aneural microorganisms adapt their locomotor patterns in real-time.European CommissionAcademy of Medical SciencesBiotechnology and Biological Sciences Research Counci
Spatiotemporal transcriptomic maps of whole mouse embryos at the onset of organogenesis
Spatiotemporal orchestration of gene expression is required for proper embryonic development. The use of single-cell technologies has begun to provide improved resolution of early regulatory dynamics, including detailed molecular definitions of most cell states during mouse embryogenesis. Here we used Slide-seq to build spatial transcriptomic maps of complete embryonic day (E) 8.5 and E9.0, and partial E9.5 embryos. To support their utility, we developed sc3D, a tool for reconstructing and exploring three-dimensional ‘virtual embryos’, which enables the quantitative investigation of regionalized gene expression patterns. Our measurements along the main embryonic axes of the developing neural tube revealed several previously unannotated genes with distinct spatial patterns. We also characterized the conflicting transcriptional identity of ‘ectopic’ neural tubes that emerge in Tbx6 mutant embryos. Taken together, we present an experimental and computational framework for the spatiotemporal investigation of whole embryonic structures and mutant phenotypes
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