Stem Cell Study of Genetics and Drug Addiction

Background - The molecular- and cellular-based mechanisms that contribute to the initiation
and development of addiction remain to be elucidated. Estimates have suggested that 40-60
percent of the vulnerability to addiction may be attributable to genetic aberrations.
Multiple chromosomal regions have been linked to addiction including those containing the
dopamine transporter (DAT) and vesicular monoamine transporter (VMAT2) genes. Current efforts
to understand how polymorphisms in these monoamine transporters contribute to the molecular
mechanisms of addiction are severely hindered by the inability to directly interrogate neural
cell types from the patients. There is great potential for patient-specific iPS cell
technology to profoundly impact our understanding of human development and disease by
providing genetically distinct, functional sources of human cells.

Objective - The objective of the research is to develop a cell-based system whereby neural
cells from afflicted individuals can be functionally assayed to interrogate the molecular
mechanisms underlying addiction.

Study population Controls (non-drug users) and opioid dependent adults receiving opioid
agonist therapy aged 21- 65 will be enrolled.

Design Participants demographic characteristics, psychosocial evaluation, and psychiatric,
medical, and drug use histories will be characterized. DNA will be collected via cheek swabs
of up to 30 potential participants for determination of dopamine transporter (DAT) and
vesicular monoamine transporter (VMAT2) gene polymorphisms. Participants (N=16) with suitable
polymorphisms will be asked to under go skin biopsies; 2 individuals for each of two
genotypes for each gene (DAT or VMAT), i.e., 8 samples from addicts and 8 samples for control
subjects. Collaborators at Case Western Reserve University will use the skin cells to derive
and characterize patient-specific, induced pluripotent stem (iPS) cells that carry monoamine
transporter polymorphisms for the hDAT1 and hVMAT2 genes. They will differentiate
patient-specific iPS cells line into dopaminergic neurons and carry out a detailed and
functional characterization of these cells to identify their molecular characteristics.

Outcome measures - Biological specimens from the addiction patients and controls will be used
to derive and characterize patient-specific, induced pluripotent stem (iPS) cells that carry
monoamine transporter polymorphisms. Patient-specific iPS cells lines will be differentiated
into dopaminergic neurons. In follow up studies, we will characterize, compare, and
functionally assay these patient-specific, iPS cell-derived dopaminergic neurons from control
and addiction patients that carry polymorphisms for hDAT1 and hVMAT2 gene to investigate any
possible association with dopamine neurotransmission variations and vulnerability to
addiction.

- INCLUSION CRITERIA:

1. 21 to 65 years old

Opioid dependent participant group only:

2. enrollment in a substance abuse treatment protocol in Archway.

Non-drug users

3. no lifetime history of drug dependence as indicated by the screening ASI and
Substance Abuse/Dependence Evaluation counselor interview.

EXCLUSION CRITERIA:

1. Relevant neurological disorders (including, but not limited to, Parkinson s disease
and Huntington s disease).

2. contraindications to skin biopsy including, but not limited to, bleeding disorders,
skin disorders, and immune disorders, that the MAI determines may alter the risk of
the biopsy.

3. cognitive impairment severe enough to preclude informed consent or valid responses on
questionnaires.

4. controls will also be excluded if they test positive for drugs or alcohol during
screening or study visits.

5. unwillingness to allow samples to be kept for future research.