Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


osu1281536983.pdf (15.67 MB)

ETD Abstract Container

Abstract Header

Regulation of Cell Fate by Caspase-3

Voss, Oliver H.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1281536983

Abstract Details

2010, Doctor of Philosophy, Ohio State University, Molecular Genetics.
Monocytes and lymphocytes are crucial components of the innate and adaptive immune system. These cells are generated daily in the bone marrow and, when unchallenged, undergo spontaneous apoptosis while requiring the activation of caspase-3. Differentiation factors, pathogens or antigens inhibit caspase-3 thereby promoting prolonged cellular life span. Upon clearance of the inflammation, activated monocytes or lymphocytes re-enter the apoptotic program allowing the restoration of cell numbers. However, dysregulation of apoptosis has been linked to numerous inflammatory diseases and hematologic malignancies including rheumatoid arthritis, atherosclerosis, monocytic leukemia, and T-cell large granular lymphocyte (T-LGL) leukemia. In this study, we found, using primary human monocytes and monocytic THP-1 cells, that caspase-3 associates with PKCδ in vitro and in vivo. We demonstrated that caspase-3 is a phosphoprotein using in vivo labeling experiments and in vitro kinase assays. We mapped the domains of these molecules involved in the interaction using purified proteins and transient over-expression expriments both in vitro and in vivo. Moreover, we identified the PKCδ-dependent phosphorylation sites on caspase-3 using mass spectrometry. In addition, we found that direct binding of the caspase-3 prodomain with Hsp27 in non-apoptotic primary human monocytes regulates monocyte survival and differentiation into primary macrophages. We found that over-expression of Hsp27 promoted survival, while silencing of Hsp27 induced caspase-3-mediated cell death. We showed a differential localization of caspase-3 and its regulator Hsp27 during the life span of monocytes and during monocyte to macrophage differentiation. These results support a model in which Hsp27 acts as an anti-apoptotic regulator of caspase-3. Moreover, we showed that Hsp27 is a key regulator of lymphocyte cell fate. Unlike other Hsps and pro- and anti-apoptotic BCL-2-family members, we found that Hsp27 expression was tightly associated with cellular life span of CD8+CD57+/-. We demonstrated that Hsp27, in a concentration-dependent manner, prolonged survival of cytotoxic CD8+CD57+, whereas silencing promoted the activity and activation of caspase-3 initiated apoptosis in CD8+CD57-. Collectively, these results provide preliminary evidence on how Hsp27 and PKCδ act as anti- and pro-apoptotic regulators, respectively, in caspase-3 mediated apoptosis. Furthermore, they emphasize the potential of Hsp27 as a useful marker of cellular life span in cells of the innate and acquired immune system and highlight Hsp27 a possible therapeutic target to induce cell death in cancer cells.
Andrea Doseff, I (Advisor)
Stephen Osmani, PhD (Committee Member)
Venkat Gopalan, PhD (Committee Member)
Harold Fisk, PhD (Committee Member)
Mary Reyland, PhD (Committee Member)
261 p.
Molecular Biology
Caspase-3, Hsp27, PKC&948; , Apoptosis, Monocytes, Macrophages, Lymphocytes

Recommended Citations

Citations

  • Voss, O. H. (2010). Regulation of Cell Fate by Caspase-3 [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281536983

    APA Style (7th edition)

  • Voss, Oliver. Regulation of Cell Fate by Caspase-3. 2010. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1281536983.

    MLA Style (8th edition)

  • Voss, Oliver. "Regulation of Cell Fate by Caspase-3." Doctoral dissertation, Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281536983

    Chicago Manual of Style (17th edition)

osu1281536983
357
© 2010, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.