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Tuck, C.

Publications and source records attributed to Tuck, C..

4 recordsLinked to original sources

Astrocyte-oligodendrocyte crosstalk dependent myelination via secreted protein YKL40

Although oligodendrocyte differentiation and myelin formation are inherent properties of oligodendrocyte progenitor cells (OPCs) that are guided by intrinsic transcriptional and epigenetic programs, this process in the brain is finely regulated by signals coming from other cells, including astrocytes. Here, we identified the astrocyte secreted protein YKL40 at the center of astrocyte-OPC cross-communication and myelination in the developing brain. We find that YKL40 is expressed by astrocytes within white matter areas in the developing brain, coinciding with the OPC differentiation and myelination. Deletion of YKL40 in astrocytes showed delayed developmental myelination and reduced OPC proliferation. Interestingly, coculture with OPCs in vitro specifically induces YKL40 expression in astrocytes, which in turn promotes OPC differentiation and OPC proliferation. Mechanistically, purified YKL40 significantly induced the expression of transcription factors Olig2 and MYRF (Myeline regulatory factor) in OPCs. Therefore, we identified a novel mechanism of OPC-astrocyte crosscommunication dependent myelination by astrocytic YKL40 in the developing brain.

neuroscience↗

Aberrant neuronal differentiation and splicing defects in Congenital Myotonic Dystrophy (DM1) iPSC models

Myotonic Dystrophy type 1 (DM1) is an autosomal multisystem disorder manifested due to unstable CTG nucleotide repeat expansion within the 3'-untranslated region of the dystrophia myotonica protein kinase (DMPK) gene. Although progress towards understanding of molecular pathogenesis in muscle and heart has been made, the pathways that affect the brain in DM1 is fundamentally unknown. In addition, the congenital DM1 manifest even more complicated brain abnormalities. Despite the wealth of existing cellular and animal models, iPSCs based studies are being fostered as they replicate the human model more closely to the disease. In view of this context, we set out to characterize the differentiation potential of congenital DM1 patient derived iPSC lines towards neuronal cells. Using neurogenin2 (NGN2) induced direct reprogramming of iPSCs into neurons and chemically defined media-induced neural induction protocol, we find that congenital DM1 mutant iPSC derived neurons exhibited precocious differentiation, as evidenced by their expression of pan-neuronal markers TUJ1 and Map2, along with increased processes extension and neurite length. Moreover, unbiased RNA sequencing analyses and qPCR validation revealed precocious and enhanced expression of several neurogenic transcription factors including, Ascl1, NeuroG2, and NeuroD1. Furthermore, immunofluorescence imaging of MBNL1 and MBNL2, RNA-splicing factors, displayed enhanced nuclear aggregations, a hallmark of the DM1 disease, in the mutant lines. Moreover, investigation of RNA splicing events identified mis-splicing in many important genes/transcripts including RMST, ANK3 and MBD1 during the neural conversion of congenital DM1 lines. These studies reveal novel paradigms that may contribute to neurological pathogenesis in CDM1 patients. These studies also provide a strong foundation for future mechanistic investigation aimed at understanding CDM1 pathology and may open new avenues for the development of gene therapy approaches for individuals with DM1.

neuroscience↗

Sphingosine-1-Phosphate Receptor 1 regulates competition dependent astrocyte morphogenesis and tiling in murine cortex.

Astrocytes are highly abundant in the mammalian brain and coordinate with neurons and other glial cells to regulate neural circuit structure, function, and blood brain barrier integrity among many to maintain proper brain homeostasis. Astrocytes perform most of these functions owing to their highly complex morphologies and hundreds of thousands of fine processes that are important in contacting neuronal synapses and other glial cells. In fact, the morphological complexity of astrocytes is regulated by the presence and activity of neurons and helps establish astrocyte territory/tiling in a non-overlapping pattern; however, the mechanisms of astrocyte tiling are not well characterized. Using a human astrocyte-mouse neuron coculture system, we previously showed that sphingosine-1-phosphate receptor 1 (S1PR1) regulates astrocyte morphogenesis in a neuronal contact dependent manner. In this study, we find that S1PR1, in vivo, regulates astrocyte morphogenesis in a cortical layer specific manner. Using astrocyte-specific S1PR1 knock out mouse models and adenoassociated viral labeling methods, we show that S1PR1 is crucial in establishing competition driven astrocyte tiling and morphogenesis in the developing brain. Furthermore, we show that JAK-STAT3 signaling regulates neuronal contact induced expression of S1PR1 in cocultured astrocytes. These studies therefore uncover a lipid signaling receptor as a major regulator of astrocyte morphogenesis and tiling in murine cortical layers.

neuroscience↗

Inkjet based 3D Printing of bespoke medical devices that resist bacterial biofilm formation

We demonstrate the formulation of advanced functional 3D printing inks that prevent the formation of bacterial biofilms in vivo. Starting from polymer libraries, we show that a biofilm resistant object can be 3D printed with the potential for shape and cell instructive function to be selected independently. When tested in vivo, the candidate materials not only resisted bacterial attachment but drove the recruitment of host defences in order to clear infection. To exemplify our approach, we manufacture a finger prosthetic and demonstrate that it resists biofilm formation – a cell instructive function that can prevent the development of infection during surgical implantation. More widely, cell instructive behaviours can be ‘dialled up’ from available libraries and may include in the future such diverse functions as the modulation of immune response and the direction of stem cell fate.Competing Interest StatementThe authors have declared no competing interest.View Full Text

bioengineering↗