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With the rapid development of biotechnologies, single-cell sequencing has become an important tool for understanding the molecular mechanisms of diseases, defining cellular heterogeneities and characteristics, and identifying intercellular communications and single-cell-based biomarkers. Providing a clear overview of the clinical applications, the book presents state-of-the-art information on immune cell function, cancer progression, infection, and inflammation gained from single-cell DNA or RNA sequencing. Furthermore, it explores the role of target gene methylation in the pathogenesis of diseases, with a focus on respiratory cancer, infection and chronic diseases. As such it is a valuable resource for clinical researchers and physicians, allowing them to refresh their knowledge and improve early diagnosis and therapy for patients.

Biomathematics. Biometry. Biostatistics --- Molecular biology --- Oncology. Neoplasms --- bio-informatica --- oncologie --- moleculaire biologie

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Cartilage is an important tissue in the skeleton. During skeletal development transient cartilage forms a template for the skeletal elements before it is replaced by bone. In the joints a non-transient form of cartilage, the articular cartilage, caps the ends of the bones and ensures very low friction between the bones to support mobility. Damage to this articular cartilage is a main feature of joint diseases. Osteoarthritis is the most common chronic joint disease, affecting millions of people world-wide and is characterized by progressive structural damage to the articular cartilage and the underlying subchondral bone, leading to pain and disability. Currently, no disease modifying treatments are available for patients with osteoarthritis, thereby defining an important unmet medical need.The Wnt signaling pathway has been identified as a key player in cartilage development, homeostasis and disease. Hyperactivation of Wnt signaling inhibits early cartilage differentiation but stimulates the last stages of the developmental differentiation process. In the articular cartilage, low levels of active Wnt signaling appear important for cell survival, but hyperactivation of the pathway is associated with abnormal differentiation of the cells and an increase in the production of tissue-destructive enzymes thereby contributing to disease processes active in osteoarthritis. Hence, Wnt signaling is considered to be a therapeutic target for this disease. Therefore, understanding of the mechanisms that regulate this pathway in cartilage is important.In this thesis, two regulatory mechanisms are investigated and demonstrated. First, activation of Wnt signaling is demonstrated to be dependent on the presence of heparin sulfate proteoglycans. Exostosin-1 (Ext1) encodes a glycosyltransferase that is required for heparan sulfate (HS) chain elongation in proteoglycan biosynthesis. HS chains serve as binding partners for signaling proteins, affecting their distribution and activity. In knockdown experiments in a chondrocyte development model, HS levels were reduced and this positively impacted on chondrogenic differentiation and proteoglycan accumulation. Ext1 knock-down reduced active Wnt signaling. Conversely, Ext1 overexpressing cells, with higher HS content, showed decreased chondrogenic differentiation and enhanced Wnt. Wnt signaling activation led to a down-regulation of Ext1 expression in chondrocytes.EXT1 therefore affects chondrogenic differentiation of precursor cells, in part via changes in the activity of Wnt signaling. As Wnt signaling also controls Ext1 expression, a regulatory loop between EXT1 and Wnt signaling during chondrogenesis is proposed.Second, interactions between Wnt signaling and intracellular multifunctional molecule ANP32A were demonstrated. ANP32A was previously shown to protect against cartilage damage by limiting oxidative stress through regulation of key anti-oxidant regulator molecule ATM expression. However, anti-oxidant treatment only partially rescued joint damage in Anp32a KO mice with osteoarthritis. Analysis of global gene expression levels by microarray in the articular cartilage of Anp32a KO mouse cartilage suggested that ANP32A also can regulate Wnt signaling. Lack of Anp32a in a cartilage differentiation process resulted in inhibition of differentiation and lack of proteoglycan accumulation, associated with Wnt hyper-activation. In human and mouse articular cartilage, Anp32a deficiency was also linked to hyper-activation of Wnt signaling.Therefore, this work reveals that EXT1 and ANP32A regulate the activity of Wnt signaling and can be considered potential targets to modulate this pathway in the treatment of osteoarthritis.