40103 Baraban Celluar Therapies

Cellular Therapies
December 9, 2013
Scott C. Baraban, Ph.D.
University of California, San Francisco
American Epilepsy Society | Annual Meeting
Disclosure
Neurona Therapeutics – Co-founder
BioCrea - Consultant
Dravet Syndrome Foundation – SAB
Grant Support
NIH (NINDS), C.U.R.E., DSF, AES, CIRM
American Epilepsy Society | 2013 Annual Meeting
Learning Objectives
• Understand current cell therapy approaches
to control intractable seizures
• Discuss potential limitations in moving these
approaches toward the clinic
American Epilepsy Society | 2013 Annual Meeting
Problem: epilepsy is a network phenomena
• increased neuronal bursting and synchronization
are a hallmark of seizures
Worrell G A et al. Brain 2004
Morgan RJ, Soltesz I. Proc Natl Acad Sci 2008
Inhibition may be the best way to constrain
an epileptic network
• Evidence of an inhibitory restraint of seizure activity in humans. Schevon et al. Nat Comm 2012
• How inhibition influences seizure propagation. Trevelyan AJ, Schevon CA. Neuropharmacology 2013
How do we increase inhibition?
• GABA mimetic drugs
• Modulation of postsynaptic GABA receptors
• Block GABA re-uptake
• New GABA interneurons?
A strategy for cell therapy
1. Identify epileptic zone
2. Cell transplantation
3. Cell integration and
seizure control
Adapted from Parent & Murphy
News & Views; Nature Neuroscience 2013
Modulation of experimentally induced epilepsy by intracerebral
grafts of fetal GABAergic neurons
Fine A, Meldrum BS. Neuropsychologia 1990
Benefits and risks of intranigral transplantation of GABAproducing cells subsequent to the establishment of kindlinginduced seizures
Nolte MW, Löscher W, Herden C, Freed WJ, Gernert M. Neurobiol Dis. 2008
Why earlier approaches did not work?
• Failure of transplanted cells to integrate
• Mixed populations of transplanted cells
• Mechanism of action??
• Not tested in appropriate animal model
A path to the clinic: preclinical studies
Obtain proof-of-principle data in an animal model of
epilepsy
• Generation of inhibitory interneurons
• Functional integration following transplantation
• Disease-modifying activity (DMA) against spontaneous
seizures and related co-morbidities
American Epilepsy Society | 2013 Annual Meeting
How to make an interneuron for cell therapy
E13.5 mouse
Source: embryonic medial
ganglionic eminence (MGE)
• neuron expressing GABA
• migration in host brain
• mature firing properties
• integration in host circuitry
MGE cells migrate widely in host brain
• P2 transplant (up to 5 mm)
• P60 transplant (up to 2 mm)
• cortex, hippocampus, amygdala
MGE cells enhance inhibition in host brain
• fetal MGE progenitor cells
• IPSC onto host pyramidal
• cortex and hippocampus
Optogenetic manipulation of MGE-derived
interneurons following transplantation
Robert F. Hunt III
MGE cells in a genetic form of epilepsy
• Kv1.1 null mice
• P2 MGE transplant
• 96% seizure reduction
Baraban SC, Southwell DG, Estrada RC, Jones DL, Sebe JY, Alfaro-Cervello C, Garcia-Verdugo JM,
Rubenstein JL, Alvarez-Buylla A. Proc. Natl. Acad. Sci. USA 2009
MGE cells in an acquired form of epilepsy
• pilocarpine model of TLE
• adult MGE transplant
• 92% seizure reduction
Hunt RF, Girskis KM, Rubenstein JL, Alvarez-Buylla A, Baraban SC. Nat. Neuroscience 2013
How to make a neuron: induced neural cells
• defined transcription factors direct cell fate
Yang N, Ng YH, Pang ZP, Sudhof TC, Wernig M. Cell Stem Cell 2011
Features of an ideal human
MGE cell line
• GABA interneuron specificity – PV, SOM, NPY
• Robust migration
• Functional integration
• Safety
• Efficacy
American Epilepsy Society | 2013 Annual Meeting
Some currently available human
stem cell lines
1. Sox1-expressing embryonic stem cells (ESC)
2. Nkx2.1-expressing embryonic stem cells (ESC)
3. induced pluripotent stem cells (iPSC) from Dravet patients
Maisano et al. J Neurosci 2012; Liu et al. Nat Biotechnol 2013; Maroof et al. Cell Stem Cell 2013; Nicholas et
al. 2013; Liu et al. Ann Neurol 2013; Jiao et al. Hum Mol Genet 2013; Shirasaka et al. Mol Brain 2013
Human SC-derived interneurons in vitro
Kevin Ess
Arturo Alvarez-Buylla, John Rubenstein
Arnold Kriegstein
GABA / b-tubulin III
Stewart Anderson
Lorenz Studer
Lori Isom
Jack Parent
Su-Chun Zhang
Potential problems: Slow differentiation
• NKX2.1::GFP human ES cells
• FACS sorted and transplanted into neonatal cortex
• 6 wk - 3 mo. post-transplantation: “undifferentiated appearance . . .
often tipped by growth cones”
Maroof AM, Keros S, Tyson JA, Ying SW, Ganat YM, Merkle FT, Liu B, Goulburn A, Stanley EG, Elefanty
AG, Widmer HR, Eggan K, Goldstein PA, Anderson SA, Studer L. Cell Stem Cell 2013
Potential problems: Slow functional
maturation
• NKX2.1::GFP human ES cells
• FACS sorted/neonatal cortex
• 7 months post-transplant
Nicholas CR, Chen J, Tang Y, Southwell DG, Chalmers N, Vogt D, Arnold CM, Chen YJ, Stanley EG,
Elefanty AG, Sasai Y, Alvarez-Buylla A, Rubenstein JL, Kriegstein AR. Cell Stem Cell 2013
Potential problems: Teratocarcinoma
• undifferentiated hES cells
• hippocampus transplant
• Sox1:GFP::Ubi:RFP cells
Germain ND, Hartman NW, Cai C, Becker S, Naegele J, Grabel LB. Cell Transplant 2012
How do we address these problems?
• Learn more about the properties of fetal human MGE cells
• Improve methods or techniques for generating hMGE cells
• Develop and characterize more appropriate animal models
for evaluation of human MGE cells
Properties of human MGE cells
• Subcortical origins of human and monkey neocortical interneurons. Ma et al. Nat Neuroscience 2013
• Non-epithelial stem cells and cortical interneuron production in the human ganglionic eminences.
Hansen et al. Nat Neuroscience 2013
“Cerebral organoids” as MGE donors?
• Cerebral organoids model human brain development and microcephaly. Lancaster et al. Nature 2013
• Self-organization of axial polarity, inside-out layer pattern, and species progenitor dynamics in human
ES cell-derived neocortex. Kadoshima et al. Proc Natl Acad Sci USA 2013
Human stem cell therapies that are
showing some promise
(but not epilepsy, yet)
• Neural stem cell engraftment and myelination in the human
brain. [leukodystrophy] Gupta et al. Sci Transl Med 2012
• Central nervous system stem cell transplantation for children with
neuronal ceroid lipofuscinosis. J Neursurg Pediatr. 2013
HuCNS-SC
oligodendrocytes, neurons and astrocytes
A path to the epilepsy clinic
Obtain IND enabling data with a human MGE cell line
• Disease Modifying Activity (DMA) in at least one animal
model of epilepsy
• Safety and “dosing” information
• Cryopreservation
• Device for delivery of human MGE cells
American Epilepsy Society | 2013 Annual Meeting
(Future) Impact on Clinical Care and Practice
Tissue grafts transiently
suppress evoked seizures
1987-1990
(Future) Impact on Clinical Care and Practice
Mouse MGE cells suppress
spontaneous seizures &
reverse comorbidities
Tissue grafts transiently
suppress evoked seizures
1987-1990
2013
(Future) Impact on Clinical Care and Practice
Human MGE cells are safe and
suppress seizures in patients
Mouse MGE cells suppress
spontaneous seizures &
reverse comorbidities
Tissue grafts transiently
suppress evoked seizures
1987-1990
2013
2025