Charting mast cell development in health and systemic mastocytosis

Hematopoietic stem and progenitor cells give rise to various blood and immune cells, including mast cells. In adults, bone marrow hematopoietic stem cells give rise to mast cell progenitors. These mast cell progenitors circulate in the peripheral blood and mature in peripheral tissues. Mast cells are activated by the cross-linking of immunoglobulin E (IgE) immune complexes bound to the high-affinity receptors, FcεRI. This event causes the release of a series of bioactive substances involved in various physiological and pathological processes. Mast cells play a key role in immunological homeostasis as essential immune cells. By contrast, mast cell dysfunction causes mast cell-related diseases. Systemic mastocytosis is a rare systemic disorder caused by abnormal accumulation of aberrant mast cells. However, in-depth studies of mast cell development in healthy individuals and in patients with mastocytosis are scarce. In the past decade, single-cell RNA sequencing technology has revolutionized the hematopoietic models, making it possible to analyze differentiation trajectories at single cell resolution. Leveraging single-cell RNA-sequencing and cell culture assays, this thesis aims to systematically explore mast cell development in healthy individuals and patients with systemic mastocytosis. In study I, we examined the cell-forming capacity of FcεRI+ progenitors in the bone marrow. In this study we found that CD203c distinguishes the erythroid and mast cell/basophil differentiation trajectories within the FcεRI+ progenitors. In study II, we analyzed the hematopoietic landscape in peripheral blood using single-cell RNA sequencing (scRNA-seq). Transcriptome analysis indicated that the genes encoding FcεRI were expressed at the hematopoietic progenitor cell stage and increased in cells that showed a mast cell gene expression signature. In vitro culture revealed the ability of the FcεRI+ progenitor population to rapidly differentiate into mature mast cells. Together, the transcriptome and cell culture assays demonstrated that CD34+ c-Kit+ FcεRI+ progenitors constitute mast cell progenitors (MCPs) in peripheral blood. Subsequent screening of cell surface receptors on the gene expression level and in vitro culture experiments identified novel regulators of MCPs. IL-3 and IL-5 promoted MCP survival. In addition, IL-3 showed a proproliferative effect on MCPs, whereas IL-5 did not. Interestingly, IL-33 significantly downregulated the expression of FcεRI on MCP, suggesting that FcεRI expression can be influenced by the extracellular environment. In study III, we aimed to explore the hematopoietic landscape in the bone marrow of patients with systemic mastocytosis (SM). In this study, we utilized single-cell RNA-sequencing to analyze the hematopoietic landscape of c-Kit+ hematopoietic progenitors isolated from bone marrow, with a focus on mast cells. Our results provide a comprehensive and in-depth analytical resource for research related to hematopoiesis in mastocytosis. Furthermore, using integrated single-cell transcriptome and immunophenotype data, we identified two distinct mast cell subpopulations with distinct expression of CD25, which is as diagnostic marker. Further comparison of CD25+ aberrant mast cells with CD25− mast cells identified a panel of disease-associated markers and revealed new potential pathogenic factors. Altogether, this thesis provides a comprehensive map of mast cell development in healthy individuals and systemic mastocytosis, laying the foundation for further studies on mast cell development in physiological and pathological states

Bodily expressed emotion understanding through integrating Laban movement analysis

Body movements carry important information about a person's emotions or mental state and are essential in daily communication. Enhancing the ability of machines to understand emotions expressed through body language can improve the communication of assistive robots with children and elderly users, provide psychiatric professionals with quantitative diagnostic and prognostic assistance, and aid law enforcement in identifying deception. This study develops a high-quality human motor element dataset based on the Laban Movement Analysis movement coding system and utilizes that to jointly learn about motor elements and emotions. Our long-term ambition is to integrate knowledge from computing, psychology, and performing arts to enable automated understanding and analysis of emotion and mental state through body language. This work serves as a launchpad for further research into recognizing emotions through analysis of human movement

RNA interference in cytochrome P450 monooxygenase (CYP) gene results in reduced insecticide resistance in Megalurothrips usitatus Bagnall

Genes of the cytochrome P450 (CYP450) superfamily are known to be involved in the evolution of insecticide resistance. In this study, the transcriptomes of two Megalurothrips usitatus Bagnall (Thysanoptera: Thripidae) strains (resistant and susceptible) were screened for detoxification genes. MusiDN2722 encodes a protein composed of 504 amino acid residues with a relative molecular mass of 57.3 kDa. Multiple sequence alignment and phylogenetic analysis showed that MusiDN2722 is a member of the CYP450 family and has characteristics of the conserved CYP6 domain shared by typical CYP450 family members. RT-qPCR (real-time quantitative polymerase chain reaction) analysis showed that MusiDN2722 was upregulated in the acetamiprid-resistant strain compared with the susceptible strain (p < 0.05), and the relative expression level was significantly higher at 48 h after exposure than at 24 h after exposure. The interference efficiency of the injection method was higher than that of the membrane-feeding method. Silencing of MusiDN2722 through RNA interference significantly increased the sensitivity of M. usitatus to acetamiprid. Overall, this study revealed that MusiDN2722 plays a crucial role in the resistance of M. usitatus to acetamiprid. The findings will not only advance our understanding of the role of P450s in insecticide resistance but also provide a potential target for the sustainable control of destructive pests such as thrips