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Biology subjects

Stefanovic, T.

Publications and source records attributed to Stefanovic, T..

3 recordsLinked to original sources

DOCK2-deficiency causes defects in anti-viral T cell responses and poor control of herpes simplex virus infection

The expanding number of rare immunodeficiency syndromes offers an opportunity to understand key genes that support immune defence against infectious diseases. However, patients with these diseases are by definition rare. In addition, any analysis is complicated by treatments and co-morbid infections requiring the use of mouse models for detailed investigations. Here we develop a mouse model of DOCK2 immunodeficiency and demonstrate that these mice have delayed clearance of herpes simplex virus type 1 (HSV-1) infections. Further, we found that they have a critical, cell intrinsic role of DOCK2 in the clonal expansion of anti-viral CD8+ T cells despite normal early activation of these cells. Finally, while the major deficiency is in clonal expansion, the ability of primed and expanded DOCK2-deficient CD8+ T cells to protect against HSV-1-infection is also compromised. These results provide a contributing cause for the frequent and devastating viral infections seen in DOCK2-deficient patients and improve our understanding of anti-viral CD8+ T cell immunity.

immunology↗

Single Cell Transcriptomics-informed Induced Pluripotent Stem Cells Differentiation to Tenogenic Lineage

During vertebrate embryogenesis, axial tendons develop from the paraxial mesoderm and differentiate through specific developmental stages to reach the syndetome stage. While the main roles of signaling pathways in the earlier stages of the differentiation have been well established, pathway nuances in syndetome specification from the sclerotome stage have yet to be explored. Here, we show stepwise differentiation of human iPSCs to the syndetome stage using chemically defined media and small molecules that were modified based on single cell RNA-sequencing and pathway analysis. We identified a significant population of branching off-target cells differentiating towards a neural phenotype overexpressing Wnt. Further transcriptomics post-addition of a WNT inhibitor at the somite stage and onwards revealed not only total removal of the neural off-target cells, but also increased syndetome induction efficiency. Fine-tuning tendon differentiation in vitro is essential to address the current challenges in developing a successful cell-based tendon therapy.

developmental biology↗

Directing iPSC Differentiation into iTenocytes using Combined Scleraxis Overexpression and Cyclic Loading

Regenerative therapies for tendon are falling behind other tissues due to the lack of an appropriate and potent cell therapeutic candidate. This study aimed to induce cell tenogenesis using stable Scleraxis (Scx) overexpression in combination with uniaxial mechanical stretch of mesenchymal stromal cells (MSCs) of different origins. Scleraxis (Scx) is the single direct molecular regulator of tendon differentiation known to date. Mechanoregulation is known to be a central element guiding tendon development and healing. Cells explored were bone marrow-derived (BM-)MSCs as well as MSCs differentiated from induced pluripotent stem cells (iMSCs). Mechanical stimulation combined with Scx overexpression resulted in morphometric and cytoskeleton-related changes, upregulation of early and late tendon markers, increased ECM deposition and alignment, and tenomodulin perinuclear localization in iMSCs, which was greater compared to BM-MSCs and controls. Our findings suggest that these cells can be differentiated into tenocytes and may be a better candidate for tendon cell therapy applications than BM-MSCs.

cell biology↗