B-cell Lymphoma-2 (Bcl-2) is an Essential Regulator of Adult Hippocampal Neurogenesis

Get your researcher involved to increase the number of surviving neurogenesis neurons. Another good dissertation. Only 89 pages.
http://www.ruor.uottawa.ca/fr/bitstream/handle/10393/23287/Ceizar_Maheen_2012_thesis.pdf?sequence=3
ABSTRACT
Of the thousands of dividing progenitor cells (PCs) generated daily in the adult
brain only a very small proportion survive to become mature neurons through the
process of neurogenesis. Identification of the mechanisms that regulate cell
death associated with neurogenesis would aid in harnessing the potential
therapeutic value of PCs. Apoptosis, or programmed cell death, is suggested to
regulate death of PCs in the adult brain as overexpression of B-cell lymphoma 2
(Bcl-2), an anti-apoptotic protein, enhances the survival of new neurons. To
directly assess if Bcl-2 is a regulator of apoptosis in PCs, this study examined the
outcome of removal of Bcl-2 from the developing PCs in the adult mouse brain.
Retroviral mediated gene transfer of Cre into adult floxed Bcl-2 mice eliminated
Bcl-2 from developing PCs and resulted in the complete absence of new neurons
at 30 days post viral injection. Similarly, Bcl-2 removal through the use of nestininduced
conditional knockout mice resulted in reduced number of mature
neurons. The function of Bcl-2 in the PCs was also dependent on Bcl-2-
associated X (BAX) protein, as demonstrated by an increase in new neurons
formed following viral-mediated removal of Bcl-2 in BAX knockout mice. Together
these findings demonstrate that Bcl-2 is an essential regulator of neurogenesis in
the adult hippocampus.

Authorizations .............................................................................................. i
Abstract........................................................................................................ xi
List of Tables ............................................................................................... xiv
List of Figures .............................................................................................. xv
List of Abbreviations..................................................................................... xvii
Acknowledgements...................................................................................... xx
Chapter 1: Introduction ............................................................................ 1
1.1 ..Adult Neurogenesis ........................................................................ 1
1.2 Progenitor Cell (PC) Development in the Hippocampus................. 2
1.3 Cell Death Occurring During Adult Neurogenesis........................... 7
1.4 Apoptosis ....................................................................................... 9
1.5 The Intrinsic Apoptotic Pathway ..................................................... 12
1.6 Players Involved with Apoptosis in Adult Neurogenesis ................. 15
Objectives and Statement of Hypothesis ................................................ 18
Chapter 2: Materials and Methods ........................................................... 19
2.1 Animals .......................................................................................... 19
2.2 Genotyping .................................................................................... 19
2.3 Retroviral Vectors & Injections ....................................................... 20
2.4 Tamoxifen Treatments ................................................................... 22
2.5 Perfusion and Tissue Collection .................................................... 23
2.6 Immunohistochemistry.................................................................... 23
2.7 Quantification Using Microscopy ................................................... 26
2.8 Statistical Analysis ......................................................................... 27
Chapter 3: Results
3.1 Retroviral-Mediated Removal of Bcl-2 Prevents the
Survival of Newborn Mature Neurons ............................................ 28
3.2 Bcl-2 Functions in the Adult Hippocampus in a BAX
xiii
Dependent Manner ........................................................................ 33
3.3 Generation of the Inducible Triple Transgenic Bcl-2
Knockout Mouse ............................................................................ 35
3.4 Removal of Bcl-2 in Nestin-Expressing Cells and their
Progeny Reduces the Recombined, Stem and Immature
Neurons at 12 days ....................................................................... 37
3.5 Removal of Bcl-2 in Nestin-Expressing Cells and Their
Progeny Altered the Mature Neuron Population 30
Days After Removal ....................................................................... 45
Chapter 4: Discussion .............................................................................. 51
4.1 Bcl-2 has a Cell-Autonomous Essential Role in
Adult Neurogenesis ........................................................................ 51
4.2 Bcl-2-Mediated Effects on the Stem-cell Like
Population ...................................................................................... 53
4.3 Differences in Neurogenesis between Floxed
Bcl-2 Mice Infected with Retroviral Cre and
nBcl-2 KO Mice............................................................................... 55
4.4 The Expression of Bcl-2 During Adult Neurogenesis .................... 56
4.5 The Role of Bcl-2 in Regulating Apoptosis in
Adult Neurogenesis ........................................................................ 56
References ................................................................................................. 59