Potential Application of Stem Cells in Treating
Retinal Degenerative Diseases
Ting Xie, PhD
Presented at the
Saudi Ophthalmology (SO) 2013 Symposium
03 – 06 March 2013
Riyadh, KSA
Potential Application of Stem Cells in
Treating Retinal Degenerative Diseases
Ting Xie PhD
Investigator
Stowers Institute for Medical Research
Professor
University of Kansas Medical Center
Saudi Ophthalmology 2013
Stem cell types
• Embryonic stem cells (ESCs): in vitro cultured stem
cells derived from the inner cell mass of the embryo at
the blastocyst stage.
• Induced pluripotent cells (iPSCs): in vitro
reprogrammed ESC-like cells from differentiated
cells using defined factors.
• Adult stem cells: rare cells in adult tissues that are
capable of self-renewing and generating functional
differentiated cells that replenish lost cells caused by
natural turnover, disease or injury.
Pluripotent ESCs can generate all the cells
derived from three embryonic germ cell layers
Chickarmane and Peterson (2008).
ESCs
Advantages:
1) Can be expanded indefinitely in vitro.
2) Have the ability to generate various cell types for
treating degenerative diseases.
Disadvantages:
1) Still challenging to differentiate ESCs efficiently into a
particular cell type.
2) Immunal rejection.
3) Teratoma formation.
4) Ethical concern.
Induced pluripotent stem cells: iPSCs
Sox2/Oct4/c-Myc/Klf4
2012 Noble Laureate
Takahashi and Yamanaka, 2006.
iPSCs
Advantages:
1) Can be expanded indefinitely in vitro like ESCs.
2) Have the ability to generate various differentiated cell types
for treating degenerative diseases like ESCs.
3) Differentiated cell types from patient-specific iPSCs lack
immunal rejection.
Disadvantages:
1) Still challenging to differentiate ESCs efficiently into a
particular cell type.
2) Teratoma formation.
Adult stem cells/progenitors
Retinal progenitor cells
Hematopoietic stem cells
Adult stem cells/progenitors
Advantages
1) Relatively easy to be guided to differentiate into a
particular cell type.
2) Normally generate only cell types in the tissue they reside in.
3) No tumor formation.
4) Some of them have been tested in clinical application:
hematopoietic stem cells, skin stem cells and corneal stem
cells.
Disadvantages
1) Difficult to be expanded in vitro.
Retinal Degenerative Diseases
Age-related macular degeneration (AMD): defective RPE cells and
photoreceptor cell loss.
Retinitis pigmentosa (RP): RPE or photoreceptor cell degeneration.
Glaucoma: loss of optic nerve and retinal ganglion cells.
Strategies for treating photoreceptor degenerative
diseases
Age-related macular degeneration (AMD):
Replacing defective RPE cells
and
Replenishing lost photoreceptor cells
Retinitis pigmentosa (RP):
Replacing defective RPE cells
and/or
Replenishing lost photoreceptor cells
Strategies for replacing defective RPE cells
1. Human ESC-derived RPE.
2. Human iPSC-derived RPE.
3. Culturing RPE cells from cadaveric eyes.
Human ESC-derived RPE
Step-wise RPE differentiation from hESCs using
growth factors.
Osakada et al. (2009). Nature Protocols 4: 811-924.
Derivation of RPE cells from hESCs
2004:
Takahashi group at RIKEN differentiated primate ESCs into functional
RPE cells. IVOS 45: 1020-5.
2008:
Coffey group in University College London differentiated hESCs into
RPE cells. Exp Neurol 214: 347-61.
2009:
Reubinoff group in Hadassah-Hebrew University generated functional
RPEs from hESCs . Cell Stem Cell 5: 396-408.
Lund group in Oregon Health and Science University also
produced functional RPEs from hESCs. Stem Cells 27: 2126-35.
2011:
On January 3, 2011, Advanced Cell Technology (ACT) was approved by
US FDA to treat dry AMD using hESC-derived RPE cells.
2012:
Schwartz group in UCLA and scientists in ACT announced their clinical
trial preliminary report on AMD. Lancet (Jan 23, 2012 online).
Efficient generation of RPE cells from hESCs
Idelson et al. (2009). Cell Stem Cell 5: 396-408.
hESC-derived RPE cells are functional
Idelson et al. (2009). Cell Stem Cell 5: 396-408.
Generation of RPE sheets directly from optic
cups formed by hESCs.
Engineering optic cups from hESCs
Nakano et al. (2012) Cell Stem Cell 10: 771-785.
hESC-derived RPE
Advantages:
-- Human ESC-derived RPEs are functional in vitro
and in vivo.
--Many available human ESC lines
Disadvantage
--Immunal rejection.
--Ethical concern
Human iPSC-derived RPE
Step-wise RPE differentiation from human
iPSCs using growth factors.
2009:
Takahashi group at RIKEN differentiated mouse and human iPSCs
into RPE cells. Neurosci Letter 458: 126-131.
2009:
Clegg group in University of California differentiated iPSCs into
functional RPEs. Stem Cells 27: 2427-34.
2011:
Golestaneh group at Georgetown University showed that human iPSCderived RPE exhibits ion transport, membrane potential, polarized
vascular endothelial growth factor secretion, and gene expression
pattern similar to native RPE. Stem Cells 29: 825-835.
Human iPSC-derived RPE cells express known markers
for native RPE cells
Na2+/K+ ATPase
Occludin
ZO-1
Native
Human
RPE
iPSCderived
RPE
Kokkinaki et al. (2011). Stem Cells 29: 825-835.
Human iPSC-derived RPE cells exhibit apico-basal
polarity and phagocytosis activity
Kokkinaki et al. (2011). Stem Cells 29: 825-835.
Human iPSC-derived RPE cells have functional voltagegated sodium channels
Kokkinaki et al. (2011). Stem Cells 29: 825-835.
Deriving RPE from optic vesicles formed by
human iPSCs.
Human iPSCs can form optic vesicle-like structures
expressing Chx10
Myer et al. (2011). Stem Cells 29: 1206-1218.
Human iPSC-derived optic vesicles can efficientlly
produce RPE cells
Myer et al. (2011). Stem Cells 29: 1206-1218.
Human iPSC-derived RPE
Advantages:
--No immunal rejection.
--No ethical concern
--Efficient generation of RPE cells
Disadvantages
--Human iPSC-derived RPE has not been shown to
be functional in vivo.
Culturing RPE cells from cadaveric eyes
Salero et al. (2012). Cell Stem Cell 10: 88-95.
Culturing RPE cells from cadaveric eyes
Advantages:
--Native and functional RPE cells
--No ethical concern
--Easy access
Disadvantages
--Difficult expansion in vitro.
--Immunal rejection
Strategies for replacing lost photoreceptor cells
Transplanted photoreceptor precursors can integrate
into the adult mouse retina
McLauren et al. (2006). Nature 444: 203-207.
Transplanted photoreceptors can form synapses with
bipolar cells of the host retina
McLauren et al. (2006). Nature 444: 203-207.
Transplanted photoreceptor precursors can restore light
response of the rho mutant retina
McLauren et al. (2006). Nature 444: 203-207.
Strategies for replacing lost photoreceptor cells
1. Human ESC-derived photoreceptor cells.
2. Human iPSC-derived photoreceptor cells.
3. Culturing human retinal stem/progenitor cells.
Step-wise differentiation of hESCs into
photoreceptor cells
Myer et al. (2009). PNAS 106: 16698-16703.
Generation of Photoreceptors from ESC-derived
retinal progenitors
2005: Sasai group at Riken Center for Developmental Biology generated
retinal progenitor cells from mouse ESCs. PNAS 102: 11331-6.
2006:
Kirk group in University of Missouri-Columbia produced mouse
ESC-derived retinal progenitor cells. Stem Cells 24:274-83.
Reubinoff group in Hadassah-Hebrew University produced human
ESC-derived retinal progenitors. Stem Cells 24: 246-57.
Reh group in University of Washington derived retinal progenitors
from human ESCs. PNAS 103: 12769-74.
2009:
Reh group in University of Washington showed that hESC-derived
photoreceptors restored the function of the crx-deficient eye.
Cell Stem Cell 4: 73-9.
hESC-derived retinal progenitors
Myer et al. (2009). PNAS 106: 16698-16703.
hESC-derived retinal progenitors differentiate
into photoreceptors in vitro
Myer et al. (2009). PNAS 106: 16698-16703.
Generation of functional photoreceptors from
hESC-derived retinal progenitors
Lamba et al. (2009). Cell Stem Cell 4: 73-9.
Isolation of photoreceptor precursors from hESCderived optic cups
Eiraku et al. (2011), Nature 472: 51-7.
Human iPSC-derived photoreceptor cells
2009:
Takahashi group at RIKEN showed that mouse and human iPSCs can
differentiated into retinal cells . Neurosci Lett 458: 126-31.
Gamm group from University of Wisconsin showed that human iPSCs
differentiate into retinal cells in vitro. Stem Cells 29: 1206-1218.
2012:
Lako group from Newcastle University developed an efficient strategy to
differentiate human ESCs and iPSCs into photoreceptor cells.
Stem Cells (Jan 20. doi: 10.1002/stem.1037.)
Human iPSCs can form optic vesicle-like structures
expressing Chx10
Myer et al. (2011). Stem Cells 29: 1206-1218.
Human iPSC-derived optic vesicles can be used to
generate functional photoreceptors in vitro
Myer et al. (2011). Stem Cells 29: 1206-1218.
Human retinal stem cell (RSC)-photoreceptors
2004:
Klassen group in U California at Irvine cultured retinal progenitors
from post-mortem human eyes, but the cell origin is not clear.
2007:
Khaw and Limb groups in Institute of Ophthalmology-London
showed that human Müller cells exhibit neural stem cell characteristics,
differentiating into retinal lineages. Stem Cells 25: 2033-43.
2009:
Young group at Schepens Eye Research Institute characterized human
fetal retinal progenitor cells.
Transplanted RSC-derived photoreceptor cells can
integrate into the degenerating retina
Rhodopsin: Rod photoreceptor marker
GFP: transplanted cells
DNA
RSC-derived photoreceptor cells can regain light
response in the rd1 mouse lacking photoreceptors.
GFP: transplanted cells
Li, Lewallen and Chen et al. Cell Research (In press)
Transplantation of stem cell-derived retinal
ganglion cells (RGCs) in treating glaucoma
1. Human ESC/iPSC-derived RGCs.
2. Human RSC-derived RGCs.
ESC/iPSC-derived RGCs
2009: James group at Rajiv Ganhdi Center for Biotechnology
differentiated mouse ESCs into RGCs. BBRC 380;230235.
2010 : Ahmad group in University of Nebraska generated
RGCs from mouse iPSCs. Stem Cells 28(4):
695-703.
2010: Ge group from Zhongshan Eye Center generated RGCs
from mouse iPSCs. IVOS 51: 5970-8..
So far, there are no human ESC/iPSC-derived RGCs!
Mouse iPSC-derived RGCs
Chen et al. (2010). IVOS 51: 5970-5978.
Mouse RSC-derived RGCs
Xie Lab (unpublished results)
RSC-derived RGCs can integrate into the injured
retina
GFP
β3 tubulin
Normal retina
GFP
Brn3b
NMDA-treated retina
GFP
Xie Lab (unpublished results) β3 tubulin
Major challenges for using stem cellderived RGCs to treat glaucoma
1. Difficult to generate large quantity of pure RGCs
from any stem cell types for transplantation.
2. It remains unknown if transplanted RGCs can
make correct synaptic connections with retinal
neurons, including bipolar cells.
3. It remains unknown if transplanted RGCs can
grow long axons to reach and correctly target to
LGN.
Conclusions
ESCs, iPSCs, adult stem cells and fetal progenitors could
be used to produce desired retinal cell types and RPE.
Different stem cells or approaches have their own
advantages and shortcomings, and should be tested
Experimentally on animal models.
Large animal retinal disease models are urgently needed
to test potential application of retinal cells derived from
various stem cell types.
Acknowledgements
Wei Yu, PhD
Tianqing Li, PhD
Shuyi Chen, PhD
Michelle Lewallen, PhD
Liang Tang, MD/PhD
Hui Lin, MD/PhD
Juan Ouyang
Yi Zhou
Yifeng Wang
Thank you!