Browsing by Author "Carson, Daniel"

Now showing 1 - 5 of 5
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    Highly glycosylated MUC1 mediates high affinity L-selectin binding at the human endometrial surface
    (Springer Nature, 2021) Francis, Lewis W.; Yao, Seydou N.; Powell, Lydia C.; Griffiths, Sean; Berquand, Alexander; Piasecki, Thomas; Howe, William; Gazze, Andrea S.; Farach-Carson, Mary C.; Constantinou, Pamela; Carson, Daniel; Margarit, Lavinia; Gonzalez, Deya; Conlan, R. Steven
    Sialyl-Lewis X/L-selectin high affinity binding interactions between transmembrane O-glycosylated mucins proteins and the embryo have been implicated in implantation processes within the human reproductive system. However, the adhesive properties of these mucins at the endometrial cell surface are difficult to resolve due to known discrepancies between in vivo models and the human reproductive system and a lack of sensitivity in current in vitro models. To overcome these limitations, an in vitro model of the human endometrial epithelial was interrogated with single molecule force spectroscopy (SMFS) to delineate the molecular configurations of mucin proteins that mediate the high affinity L-selectin binding required for human embryo implantation.
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    Molecular Imaging of Mucin-Expressing Colon tumors Using Targeted Hyperpolarized Silicon Nanoparticles
    (2016-11-22) Liu, Julie Xinli; Constantinou Papadopoulos, Pamela; Carson, Daniel
    Colon cancer remains a leading cause of death due to limitations in clinical detection and prevention. Accordingly, an improved method with higher degree of detection sensitivity is due, where tumor surface markers can be targeted, and non-invasively imaged. MUC1 is a transmembrane mucin that is normally expressed only the apical aspect of colonic epithelia. MUC1 is a heavily glycosylated, large molecular weight protein that extends 200 to 500 nm above the cell surface. Accompanying cellular transformation and tumor development, MUC1 often becomes aberrantly expressed, including loss of polarized expression and altered glycosylation. With MUC1 as target, MUC1 antibody-functionalized silicon nanoparticles (SiNP may be used as uniquely hyperpolarizable imaging agents for the ultimate purpose of in vivo clinical applications for early colon tumor detection. This study aims to develop MUC1-targeting SiNPs that can undergo the hyperpolarization process to be utilized as sensitive image contrast agents to detect MUC1-expressing tumors. With cancer-associated transmembrane mucins found in most GI tract cancers, this silicon nanoparticle-based tumor diagnostic approach offers the potential to be expanded to detect tumors of other GI tissues and organs and establishes the basis for using other surface markers as detection targets.
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    Neural Crest and the Cornea: Transformation of the transcriptome and the role of Nephronectin during ocular development
    (2020-09-15) Ma, Justin; Lwigale, Peter; Carson, Daniel
    Corneal development is an intricate process that involves signaling and interactions between the periocular neural crest cells (pNC)s, presumptive corneal epithelium, lens, and the extracellular matrix. Cross-talk between these divisions are critical in regulating the migration, proliferation, and differentiation of the periocular neural crest to form the cornea. Major signaling pathways (retinoic acid, TGFβ, and Wnt) and cell-matrix interactions are essential for corneal formation, but the mechanisms of how they influence pNC behavior are not well understood. In this study, I use RNA-sequencing to establish the transformation in the transcriptomic profile from the pNC to the formation of the cornea. With this data, I establish the pNC identity and analyze how differential regulation of the major signaling pathways regulate pNC behavior and contribute to the corneal cell fate. In addition, I take note of the expression of key extracellular matrix, matrix-remodeling, and cell-matrix receptor genes and link their differential regulation to essential corneal developmental events. Within this niche, I focused on studying the role of a particular strongly expressed matrix protein, nephronectin (Npnt). Npnt has been linked to many embryonic developmental roles including the kidney, bone, heart, tooth, and lungs. However, a role for it has yet to be described in the cornea. Using both the chick and mouse as my model organisms, I found that both Npnt and its cellular receptor integrin α8β1 were strongly expressed in the migrating pNC. This led to the hypothesis that Npnt/Itgα8β1 has a role in regulating pNC behavior during corneal development. Using functional studies by knocking down or overexpressing Npnt in the chick, I show that loss or gain of Npnt correlates to a decrease or increase of corneal thickness and cell counts, respectively. This result was further confirmed by knocking down Itga8 and see corresponding decrease in corneal thickness, suggesting that Npnt/Itgα8β1 has a role in cell migration and/or proliferation. In clarifying respective assays. I found that cell proliferation was not increased by overexpressing Npnt and that Npnt-mediated signaling, which is a stronger inducer of periocular neural crest migration in vitro, is abrogated by inhibition of Itgα8β1. Altogether, in this thesis, I analyzed the transcriptomic profile in the developing cornea and characterize a previously unknown ECM-receptor interaction (Npnt/Itgα8β1), which may be a novel regulator of pNC migration and corneal development. Identifying a functional role for Npnt also validates the potential of the transcriptomic study as a valuable resource to identify novel genes essential for corneal development and potential targets for corneal therapies.
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    Role of Chemokine Signaling and Heparin Binding Growth Factors During Ocular Neurovascular Patterning
    (2019-08-07) Cui, Ruda; Lwigale, Peter Y; Carson, Daniel
    The embryonic eye provides a unique context in which we can study the mechanisms of neurovascular patterning and wound healing. The anterior eye requires highly regulated signaling for the proper formation of an avascular, highly innervated, and transparent cornea. By studying ocular development in avian and murine models, we can begin to understand how signals in the embryo regulate interactions of the neural crest cells and ocular ectoderm for the proper formation of the anterior eye structures. The purpose of this work is to elucidate the functions of a chemokine (CXCL12), and two heparin-binding growth factors (midkine and pleiotrophin) during anterior eye development and neurovascular patterning. CXCL12 and its receptor CXCR4 are required for the proper vascular patterning in other organ systems, but their functions in the eye have yet to be discovered. Here I demonstrate that CXCL12-CXCR4 signaling has two major functions during ocular development: first, CXCL12 expression in the trigeminal placode is required for the proper formation of the trigeminal ganglion; second, CXCL12 expression in the periocular neural crest is required for proper vascular remodeling during later ocular development. Disruption of CXCL12 signaling in either the placode or neural crest result in significant neurovascular defects of the anterior eye. Midkine (MDK) and pleiotrophin (PTN) are two secreted proteins which make up their own family of heparin-binding growth factors. MDK expression can be induced by retinoic acid, which is an important signal for general ocular development. Here I report MDK and PTN expression during corneal and retinal development. Both MDK and PTN were expressed in the migrating neural crest, but otherwise had generally complimentary expression patterns. Although MDK and PTN were conserved in the anterior eye between chick and mouse, they had differential expression during retinal development. I also demonstrate that MDK and PTN in the anterior eye may signal to trigeminal nerves through ITGB1 and RPTPZ. Lastly, I present a novel method to study embryonic wound healing in culture. The embryonic cornea possesses regenerative properties not found in the adult, and can maintain its transparency by healing nonfibrotically. However, current methods of studying embryonic wound healing are limited in its efficiency and adaptability. Here I provide a protocol to study mechanisms of wound healing in an ex vivo model that allows for higher throughput, reproducibility, and adaptability. The results presented in this document give a glimpse of the intricate and highly regulated signaling required during ocular development. Better understanding of the molecular mechanisms are required for the creation of better therapeutics for ocular neurovascular diseases and wound healing.
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    Targeting Mitochondria Metabolisms for Novel AML Therapy Development
    (2021-12-03) Pei, Jingqi; Kirienko, Natasha V.; Carson, Daniel
    Mitochondrial dysfunction contributes to a wide variety of pathologies, including neurodegenerative diseases, cancer, metabolic diseases, and aging. As a consequence, oncogenesis and tumor progression heavily depends on the mitochondrial metabolism. I investigated the potential of using mitochondrial targeting drugs to selectively remove leukemia, a type of cancer that has been previously identified to be sensitive to mitochondria-targeting drugs. I optimized Hoeschst/PI dual-staining assay for quick, high-throughput screening of leukemia cell’ viability under mitochondria-targeting drugs treatments. Through combination of mitochondria-targeting drugs and anti-cancer chemotherapeutic agents, I observed high synergistic effect in the removal of leukemia in these combinations. I characterized several changes in mitochondria bioenergetic parameters that are correlated with the sensitivity of mitochondria-targeting drug to leukemia. These observations also applied to primary AML samples extracted from patients. Mitochondria health is actively surveilled by several different systems to ensure the preservation of cellular viability. Mitophagy is a conservative process that removes superfluous or damaged mitochondria. I identified 8 compounds with mitophagy activation effect that can stabilize PINK-1/PINK1 in C. elegans with my colleague Dr. Elissa Tjahjono. I observed these compounds induced selective removal of leukemia alone or in combination with other anti-cancer chemotherapeutic agents. Furthermore, these compounds reduced paralysis level in C. elegans model of neurodegenerative diseases. Taken together, activation of mitophagy using these compounds may be a novel method to develop selective therapy for leukemia and neurodegenerative diseases.