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Aberrant subcellular targeting of the G185R neutrophil elastase mutant associated with severe congenital neutropenia induces premature apoptosis of differentiating promyelocytes & expression and function of the transient receptor potential 2 (TRPM2) i

Massullo, Pam
http://rave.ohiolink.edu/etdc/view?acc_num=osu1172865905

Abstract Details

2007, Doctor of Philosophy, Ohio State University, Molecular, Cellular, and Developmental Biology.
Part I: Severe congenital neutropenia (SCN) is a bone marrow failure disorder characterized by extremely low numbers of peripheral blood neutrophils, a myeloid maturation arrest in the bone marrow, and recurrent infections. Despite dramatic improvements in survival and quality of life with granulocyte colony-stimulating factor (G-CSF) therapy, patients with SCN have a life-long increased risk of developing leukemia. Mutations in the neutrophil elastase (NE) gene are present in most patients with SCN. However, the mechanisms by which these mutations cause neutropenia remain unknown. The effects of expression of the G185R mutation associated with a severe SCN phenotype was examined. We show that the mutant enzyme accelerates apoptosis of differentiating but not of proliferating cells. Using metabolic labeling, confocal immunofluorescence microscopy, and immunoblot analysis of subcellular fractions, we also demonstrate that the G185R mutant is abnormally processed and localizes predominantly to the nuclear and plasma membranes rather than to the cytoplasmic compartment observed with the wildtype enzyme. Expression of the G185R mutant appeared to alter the subcellular distribution and expression of adaptor protein 3 (AP3), which traffics proteins from the trans-Golgi apparatus to the endosome. These observations provide further insight into potential mechanisms by which NE mutations cause neutropenia and suggest that abnormal protein trafficking and accelerated apoptosis of differentiating myeloid cells contribute to the severe SCN phenotype resulting from the G185R mutation. A novel mutation in the extracellular portion of the G-CSFR in a patient with SCN without AML who was refractory to G-CSF treatment is reported. Part II: Dendritic cells (DCs) orchestrate immunity by amplifying innate and initiating adaptive immune responses. DCs traffic in response to chemokines and inflammatory mediators. Although most chemokine receptor stimulation in DCs is accompanied by intracellular Ca2+ release and Ca2+ influx, the identity and functions of the ion channels responsible remains largely unknown. Here we aimed to investigate the expression and function of the transient receptor potential (melastatin-related) 2 (TRPM2) ion channel to provide insights into mechanisms of ADPR-gated TRPM2 activation, and advances our understanding of how inflammatory signals, such as chemokines, modulate immunity, as DC trafficking is critical for efficacious immune responses.
Belinda Avalos (Advisor)
209 p.
severe congenital neutropenia; granulopoiesis; G-CSFR; TRPM2

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Citations

  • Massullo, P. (2007). Aberrant subcellular targeting of the G185R neutrophil elastase mutant associated with severe congenital neutropenia induces premature apoptosis of differentiating promyelocytes & expression and function of the transient receptor potential 2 (TRPM2) i [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1172865905

    APA Style (7th edition)

  • Massullo, Pam. Aberrant subcellular targeting of the G185R neutrophil elastase mutant associated with severe congenital neutropenia induces premature apoptosis of differentiating promyelocytes & expression and function of the transient receptor potential 2 (TRPM2) i. 2007. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1172865905.

    MLA Style (8th edition)

  • Massullo, Pam. "Aberrant subcellular targeting of the G185R neutrophil elastase mutant associated with severe congenital neutropenia induces premature apoptosis of differentiating promyelocytes & expression and function of the transient receptor potential 2 (TRPM2) i." Doctoral dissertation, Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1172865905

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.