25/12/50. Delayed Transplantation of Adult Neural Precursor Cells Promotes Remyelination and Functional Neurological Recovery after Spinal Cord Injury

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1 2 Karimi-Abdolrezaee et al. J Neuroscience 26(13): ; (2006) Delayed Transplantation of Adult Neural Precursor Cells Promotes Remyelination and Functional Neurological Recovery after Spinal Cord Injury Akkradate Siriphorn SIMP/D Dec 26 th, Spinal Cord Injury (SCI) 2.5 million SCI Thuret (2006) Sensory function Motor function 130,000 new case/year Thuret (2006) 5 Spinal Cord Injury 6 Surviving axons exhibit demyelination after SNI Necrosis cell death Apoptosis cell death Vascular disruption Glial scar Excitatory cytotoxicity Surviving axon Cause 1. Oligodendroglial cell death 2. Limited myelin gene expression 3. Limited oligodendrocyte renewal Li (1996), Crowe (1997), Casha (2001) Central cavitation Degeneration of spinal cord white matter Major contribution to pathophysiology of SCI Demyelinated fiber Dysfunction of conduction properties because of the changes in axonal K + channel expression and distribution Blight (1983), Fehlings (1996), Nashmi (2001) 1

2 7 Endogenous NSCs can differentiate to oligodendrocyte but not enough 8 Cell Replacement Therapy As Potential Strategy Endogenous Neural Stem Cell Neural Stem Cell Cell replacement therapy Oligodendrocyte Oligodendrocyte Even after infusion of exogenous growth factor, endogenous oligodendrocyte renewal is not enough to promote remyelination Kojima (2002), Martens (2002) Oligodendrocyte Transplanted cells To restore oligodendrocyte population To promote remyelination after SCI 9 Adult neural stem cells: new avenue for Cell Therapy 10 Neural Precursor cells Adult Neural Stem Cell Embryonic Stem Cells Stem cell Progenitor cell Self renewal Adult Neural Stem Cells (NSC) Forebrain Single ecell Growth factor Proliferation and formation a free-floating colony Neurosphere Adult Neural Stem Cell Embryonic Stem Cells Multipotency Raynold (1992), Richards (1992) Spinal cord Residing in forebrain spinal cord Maintaining for life 1% NSCs 99% Progenitor cells Neural Precursor cells (NPCs) 11 NPCs for spinal cord repair Adult Neural Precursor Cells (NPC) Forebrain SNI Spinal cord Adult NPCs Not been fully characterized 2

3 13 Objective To explore the potential efficacy Adult neural precursor cells (NPCs) transplantation Promote: 1. Remyelination 2. Functional recovery? Compressive Spinal Cord Injury Isolations of Adult Neural Precursor cells (NPCs) 18 Culturing of Adult Neural Precursor cells (NPCs) Yellow fluorescent protein (YFP) - expressing i mice i Killed by cervical dislocation Brain were removed Transferred to artificial CFS (acsf) solution Free-floating neurospheres Mechanically Dissociated Single cell suspension Cells were plated on uncoated flasks in serum-free medium for 7d Mechanically dissociated into a cell suspension Trypsin was inactivated Transferred to acsf + Trypsin, hyaluronidase + kynurenic acid Subventricular zone of forebrain were dissected Cells were grown in a culture medium + neurosphere growth medium + 1% FCS, EGF and bfgf for 2 days Cells were plated on Matrigel-coated multichamber glass slide (4000 cells/chamber) 3

4 19 RESULT Morphology of dissociated cells from neurosphere colonies 20 2 days cultured in media containing EGF and bfgf YFP = cell from YFP-expressing mice Nestin = neural precursor cells 21 In vitro immunocytochemistry 22 Heterogeneous population of differentiated cells from NPCs 1 week cultured in media containing 1%FCS without growth factor 4% PFA PBS Blocking 60% 20% Cells were induced differentiation by culture in culture media without growth factor for 7 days Fixed with 4% PFA Washed with PBS Blocked with 1% BSA, 5% normal goat serum, 0.3% triton X-100 in PBS for 1 hour at room temp Astroglia NPCs Mature oligodendrocyte Confocal microscope DAPI Counterstained with DAPI Incubated with fluorescent Alexia o Ab for 1 hour at room temp anti nestin (1:200) anti-gfap (1:100) anti-pdgf-α R (1:40) anti-cnpase (1:100) anti-map-2 (1:200) Incubated with 1 o Ab for 2 hour at room temp <1% Neural Stem Cells (NSC) 5% Oligodendrocyte precursor cells 10% Mature neuron Animal groups Transplantation ti of adult NPC 97 adult female Wistar rats Plain injured group Only received SCI Injured control group Received SCI + growth factors, minocyclin and cyclosporine A Injured NPC-transplanted group Received SCI + growth factors, minocycline, cyclosporine A and NPC transplantation 4

5 25 26 Spinal cord injury model Anesthetized with 1% halothane T6-T8 laminectomy Their bladders were manually expressed (3 times/day) until return of reflexive bladder control 23 g aneurysm clip compression injury for 1 min at T7 levels NPCs transplantation 2 week after injury Anesthetized with 1% halothane Spinal cord was reopened at injury site 300, NPCs were injected into dorsal spinal cord Osmotic minipump Enhanced survival of transplanted cells by infusion with PDGF-AA, bfgf, EGF, gentamycine, cyclosporine A, minocyclin Tissue sections Immunostaining Anesthetized with pentobarbital Transcardially Post-fixed with perfused with NSS + 4% PFA + 10% 4%PFA sucrose at 4 o C overnight Cryoprotected in 20% sucrose for hat4 o C SC 4-03 Air dried at room temp for 10 min PBS Washed with PBS for 10 min Blocking Blocked with 1% BSA, 5% non-fat milk, 0.3% triton X-100 in PBS for 1 hour at room temp Incubated with 1 o Ab at 4 o C overnight SC 4-03 DAPI Stored at -70 o C until use Mounted on gelatin-coated slide 10 µm Cryosectioning Confocal microscope Counterstained with DAPI Incubated with fluorescent Alexia 594 or Alexia o Ab for 1 hour at room temp 5

6 31 Primary antibody 32 Transplanted cells survive within injured spinal cord 1 o Antibody Dilution Marker for Anti-nestin 1:200 Neural precursor cells Anti-PDGF-αR 1:40 Oligodendrocyte progenitor Anti-GFAP 1:100 Astrocytes Anti-APC 1:40 Anti-MBP 1:1000 Mature oligodendrocyte Anti-MAP-2a,b 1:200 Neurons Anti-β tubulin III (TujI) 1:500 Anti-NF200 1:500 Axons Anti-p75 1:500 Schwannn cells 8 Week after transplantation 8 week Survival (YFP-positive) cells = 110,204 ± 61,911 cells Original cell numbers = 300, cells Percentage of cell survival = % 33 Transplanted cells migrate within injured spinal cord 34 Dorso-ventral direction Transplanted cells migrate within injured spinal cord 8 week Rosto-caudal direction The rostocaudal direction was the preferred direction of migration. 35 NPCs reside predominantly in the white matter area 36 Transplanted NPCs differentiated in vivo Tuj1 = neuronal marker 53% YFP = Transplanted NPCs YFP+ cells reside mainly in the white matter 6

7 37 Transplanted cells ensheath the axon 38 YFP MBP Transplanted cells NF200 Mature Oligodendrocyte YFP MBP NF200 Axon BrdU incorporation study BrdU incoperation study 2 h BrdU = proliferating cells Transcardially Rats received BrdU injection perfused with NSS + (3 injection/day for 3 day; i.p.).) 4% PFA Cryoprotected in 20% sucrose for h at 4 o C 10 µm Cryosectioning SC 4-03 YFP = cell from transgenic mice Rare YFP+/BrdU+ cells Confocal microscope Incubated with fluorescent Alexia o Ab for 1 hour at room temp Incubated with BrdU Ab at 4 o C overnight 10 µm Cryosectioning Few proliferative profiles among the transplanted NPCs Assessment of myelination Toluidine blue Spinal cord underwent postfixation and osmification in 1% OsO 4 Embedded in Araldite 502 embedding media Semithin section were cut Stained with Toluidine blue Viewed under Deconvolution microscope 7

8 43 Remyelinating ability of transplanted NPCs 44 Myelin Ratio Plain injured Injured control NPC-Transplanted (SCI alone) (SCI + Factor) (SCI + Factor + NPC) D Myelin Ratio (MR) = d d Axon diameter D Fiber diameter Completely demyelination MR = 1 Myelinated fiber MR > Myelin ratio (SCI alone) (SCI + Factor) (SCI + Factor + NPC) Immunoelectron microscopy Immunoelectron microscopy DAB DAB OsO 4 EtOH Transcardially perfused with 4% PFA % glutaraldehyde Embedded in 3% agar Vibrotome Preincubated in section ( µm) H 2 O 2 Incubated in 0.04% DAB for 30 min Incubated in 0.04% DAB % H 2 O 2 for 15 min Treated with 1% osmiun tetroxide overnight Dehydrated in graded EtOH GTA Post-fixed in 0.1% glutaradehyde for 10 min at room temp Incubated with anti-rabbit HRP 2 o Ab at 4 o C overnight Incubated with Rabbit Anti-GFP Ab at 4 o C overnight Blocking Blocked with 1% BSA, 5% non-fat milk, 0.05% triton X-100 in PBS for 3 hour at room temp Examined with TEM Uranyl Lead citrate citrate Counterstained with Uranyl and lead citrate Thin section were cut on ultratome Embedded in Araldite-502 / Embed-812 embedding media 8

9 49 Remyelination was derived from transplanted cells 50 NPC-Transplanted Footprint analysis Footprint Analysis Green dye Red dye Angle of rotation Forelimb Hindlimb Line connecting 3 rd toe Stride line at the center of paw pad 1-m-long paper covered narrow runway Interlimb coordination Forelimb Hindlimb Distance between the center of pads of the ipsilateral forelimb-hindlimb Plain injured (SCI alone) Control (SCI + Factor) NPCs (SCI + Factor + NPC) Footprint Analysis Plain injured (SCI alone) Control (SCI + Factor) NPCs (SCI + Factor + NPC) 9

10 55 56 Grid-Walking Analysis Grid-walking analysis 1-m-long horizontal runway of wooden grid hindlimb falls 30 cm hindlimb falls Camera Number of hindlimb falls were counted. Baseline for each animal was performed before injury. In baseline measurements, no stepping errors were observed. Plain injured (SCI alone) Control (SCI + Factor) NPCs (SCI + Factor + NPC) Basso-Beattie and Bresnahan open-field locomotion score 21-POINT SCALE HINDLIMB MVT TWO EXAMINERS 4 MIN/RAT 59 BBB score 0 = No movement 21 = Normal locomotion Plain injured (SCI alone) Control (SCI + Factor) NPCs (SCI + Factor + NPC) 10

11 61 Discussion 62 Promoting survival of transplanted cell Transplantation of brain derived adult NPCs Replace oligodendrocyte Promote remyelination Improve functional Neurological recovery Preliminary transplanted experiments Potential therapeutic intervention for SNI and other myelin deficiency diseases 63 Promoting survival of transplanted cell 64 Promoting survival of transplanted cell EGF bfgf PDGF-AA Infusion of growth factor Inhibited invasion of macrophages/ microglia Used to expand NPCs isolated from subventricular zone Reynold (1992), Vescovi (1993), Craig (1996) Minocycline Enhance proliferation of NPCs Inhibits microglia Vescovi (1993), Ray (1994) activation after brain ischemia and SCI Stimulate differentiation of oligodendrocyte Raff (1988) Regulate proliferative response of adult oligodendrocyte Lachapelle (2002), Frost (2003) Yrjan-heikki (1999), Stirling (2004) Neuroprotective by block cytochrome C and caspase dependent apoptosis Zhu (2002), Wang (2003) This study Percentage of Survival Cell = 36.7 % Suppress the immune response Cycloporin A 65 In vitro differentiation of adult NPCs 66 Transplanted cells remain confined to white matter 60% <1% Astroglia Neural Stem Cell (NSC) 5% NPCs Oligodendrocyte precursor cells 20% Mature oligodendrocyte 10% Mature neuron Reynolds (1992), Morshead (1994) NPCs Multipotent cells Attracted by demyelinated axons? GM WM Transplanted cells reside mainly in the white matter Repelled by gray matter 11

12 67 Transplanted cells differentiated into oligodendrocyte linage 68 Lack of neurogenesis by transplanted adult NPCs ~ 50% of transplanted NPCs differentiated into oligodendrocyte lineage 53% Demyelination Loss of oligodendrocyte 19% oligodendrocyte precursor cells 33% mature oligodendrocyte Transplantation of adult NPCs can compensate the loss of oligodendrocyte population after spinal cord injury Lack of neurogenesis by adult derived progenitor cells when transplanted in vivo Cao (2001), Vroemen (2003), Pferfer (2004) 69 Transplanted cells differentiated into oligodendrocyte linage Infusion of growth factors induced generation of neurons from endogenous NPCs around Lateral ventricles 4 th ventricle Spinal canal Marten (2002) Endogenous environment of spinal cord may be Promoting factors Inhibitory factors Appropriate strategies are required to induce adult NPCs neuron 71 CONCLUSION Conclusion Adult neural precursor cells (NPCs) Compression Spinal Cord Injury Promote: 1. Remyelination 2. Functional recovery The strategy of using adult NPCs for repair of CNS lesions in the clinical setting requires further development. 12