| dc.contributor.advisor | Katschinski, Dörthe Prof. Dr. | |
| dc.contributor.author | Swain, Lija | |
| dc.date.accessioned | 2014-07-14T09:29:36Z | |
| dc.date.available | 2014-07-14T09:29:36Z | |
| dc.date.issued | 2014-07-14 | |
| dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-0022-5F15-A | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-4592 | |
| dc.language.iso | eng | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/3.0/ | |
| dc.title | Prolyl-4-hydroxylase domain 3 (PHD3) is a critical terminator for cell survival of macrophages under stress conditions | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Nikolaev, Viacheslav Dr. | |
| dc.date.examination | 2014-07-07 | |
| dc.description.abstracteng | On molecular level, cells sense changes in oxygen availability through the prolyl-4-hydroxylase domain enzymes (PHDs), which in turn regulate the protein stability of the α-subunit of the transcription factor hypoxia-inducible factor (HIF). By using molecular oxygen PHDs 1 - 3 hydroxylate two specific proline residues thereby marking HIFα for proteasomal degradation. Among the three PHD isoforms the constitutively expressed PHD2 is the main regulator of HIFα stability and thus hypoxia-inducible gene expression in normoxia. PHD3 is highly induced under hypoxic conditions and serves as a negative feedback regulator. Especially PHD3 has been additionally associated with apoptotic cell death. I hypothesized that PHD3 plays a role in cell-fate decisions in macrophages. Therefore, myeloid-specific PHD3 knockout mice (PHD3-/-) were created and analyzed. PHD3-deficient bone marrow-derived macrophages (BMDM) showed no altered HIF-1α or HIF-2α stabilization or increased HIF target gene expression in normoxia or hypoxia. Macrophage M1 and M2-polarization was unchanged likewise. Compared to macrophages from wild type littermates PHD3-/- exhibited a significant reduction in TUNEL positive cells after serum withdrawal. Under the same conditions the PHD3-/- macrophages also showed less Annexin V staining which detects the membrane disruption indicating a reduced early apoptosis. Application of apoptotic inducers such as S-nitroso-N-acetyl penicillamine (SNAP) or staurosporine also showed PHD3-/- cells to be less apoptotic. Additionally, calcein uptake results indicate that PHD3-/- macrophages are more viable. When the supernatant (medium) from the cultured macrophages was exchanged between the genotypes after 24 hrs of culture, then PHD3-/- macrophages showed more Annexin V staining suggesting that at least in part a secreted factor is involved in the PHD3 induced apoptosis mechanism. In an unbiased transcriptome screen the expression of a secretory glycoprotein angiopoietin-like protein 2 (Angptl2) expressions was found to be reduced in PHD3-/- BMDM under stress conditions. Addition of recombinant Angptl2 rescued the anti-apoptotic phenotype demonstrating that it is involved in the PHD3-mediated response towards apoptotic stimuli in macrophages. Additionally Angptl2-/- BMDM showed decreased apoptosis compared to wild type which support the lower expression of Angptl2 in PHD3-/- BMDM followed by decreased apoptosis. My data suggests that the anti-apoptotic effects in the PHD3-/- BMDMs are at least partially mediated by an altered production and response to Angptl2. | de |
| dc.contributor.coReferee | Schwappach, Blanche Prof. Dr. | |
| dc.contributor.thirdReferee | Dobbelstein, Matthias Prof. Dr. | |
| dc.contributor.thirdReferee | Lutz, Susanne Prof. Dr. | |
| dc.contributor.thirdReferee | Meyer, Thomas Prof. Dr. | |
| dc.subject.eng | Angptl2 - angiopoietin-like protein 2 | de |
| dc.subject.eng | PHD3- prolyl-4-hydroxylase domain 3 | de |
| dc.subject.eng | BMDM - Bone marrow derived macrophages | de |
| dc.subject.eng | HIF- Hypoxia inducible factor | de |
| dc.subject.eng | SNAP - S-nitroso-N-acetylpenicillamine | de |
| dc.subject.eng | Stauro - Staurosporine | de |
| dc.subject.eng | TUNEL - Terminal deoxynucleotidyl transferase dUTP nick end labeling | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-11858/00-1735-0000-0022-5F15-A-9 | |
| dc.affiliation.institute | Medizinische Fakultät | de |
| dc.identifier.ppn | 790447940 | |