Ischemia-induced Neurogenesis of Neocortical Layer 1 Progenitor Cells

Nature Neuroscience VOLUME 13 | NUMBER 2 | February 2010

Speaker : 陳意涵

Date : 2010/10/04

Commentator : 許桂森 老師

View of Adult Neurogenesis

Nature Reviews Neuroscience Vol.8 Jun. 2007

Adult Neurogenesis

Annu. Rev. Neurosci. 2005.28:223-250.

Adult Neurogenesis

Annu. Rev. Neurosci. 2005.28:223-250.

Factors Modulate Neurogenesis

• Upregulate NeurogenesisExerciseEnvironmental Enrichment Pregnancy Stroke

• Downregulate NeurogenesisStress Aging

Physiol Rev 85: 523–569, 2005

Neocortical Neurogenesis

Ann Neurol 2007;61:199–208

NeuN : Neuronal nucleiDCX : doublecortin

2 weeks after H-I

5 weeks after H-I

Brain Injury & Stroke

Ischemia

http://www.biologycorner.com/worksheets/rat_circulatory.html

Ki67 : cell proliferation marker

BrdU & pH3 : cell proliferation marker

GAD67 :

Nkx2.1 & MafB : ganglionic eminence

Layer 1 Ki67 and GAD67 double-positive cells might be ganglionic eminence–derived proliferating cells.

NeuN : Neuronal cell markerCD11b : microglia cell marker

Time-course quantification

Time-course quantification

F : FrontalM : Motor S : SomatosensoryV : Visual

Left : neostriatumRight : thalamic nuclei

1.56 fold

NG2 / Olig2 : Reactive Gliosis

Time course Ki67-/GAD67+/ GFP+ cells, which were produced from

layer 1 Ki67+/ GAD67+/GFP+ cells by the ischemic stimuli, migrated to the deepest layers within 7–10 d of

the ischemia treatment

TuJ1 & HuC/D : immature neuronal markerMAP2 : mature neuronal markerGFP-positive cells in layer 2–6 share the

morphological and molecular characteristics of neurons

SYN1 (synapsin 1) promoter

Few layer 2–6 GFP-positive cells were colabeled with glial marker antibodies

GFAP: astrocytesOligo : Oligodendrocytes (rat glial membrane & whole-brain white matter )CD11b : microglia

GFAP : astrocyteOligo : oligodendrocyte

Magenta : neuron marker HuC/D

New neocortical neurons may not be generated in the SVZ or white matter in these conditions

8 weeks post ischemia

NPY : neuropeptide Y ChAT : choline acetyltransferaseSOM : somatostatinCR : Calretinen

Newly generated neurons matured and/or that the newly generated immature neurons died

New neurons might be short lived

The expression of CR and SOM is mutually exclusive

Layer1 Ki67+/GAD67+/GFP+Efficiency r =

Layer1 Ki67+/GAD67+

Environmental Enrichment

Nature Vol.386 493-495,3, April ,1997

1.Attenuates stress responses2.Protects rats from excessive anxiety in the face of new challenges

c-FOSEnriched Environment

Standard

Neuroscience Vol. 99, No. 1, pp. 7±16, 2000

Barrel cortex of the primary somatosensory cortex

Control : original cage Enriched : new enriched environment

At least some of the newly generated neurons were functionally incorporated into the cortical circuit

Glial cells in the layer 3–4 of somatosensory cortex

NeuN & GAD67 : neuronsS100 β : astrocytesOligo : oligodendrocytesCD11b : microglias

Almost all c-Fos expression was confined to neurons 4 weeks after ischemia

Summary

• NPCs exist in the neocortical layer 1 of the adult rats

• The layer 1 NPCs produced GABAergicinterneurons under ischemic conditions

Discussion

Discussion

Thank you for attention!

Recombinant Retrovirus Vector is Confined in Layer1

Inject Hoechst 33258

Markers

Neurogenesis Neuron migration(cell proliferation)

VZ IZ CP SVZ

Whisker System