hematopoietic stem cell based gene therapy for hiv diseases dong sung an, m.d., ph.d associate...
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Hematopoietic stem cell based gene therapy for HIV diseases
Dong Sung An, M.D., Ph.DAssociate professor
UCLA School of NursingUCLA AIDS Institute
Long-term goals
•Advance stem cell based gene therapy research.•Develop a new therapy for cure for HIV infected individuals.
Limitations in the current treatment for HIV infection
• No cure. • Rapid rebound of viremia if patients stop medication.• Everyday life long medication• Treatment adherence is difficult. • Side effects.• Medication costs ($100,000-$400,000 for one patient’s
life).• Emergence of multi-drug resistant HIVs. • Limited treatment access world wide. • No vaccine
Natural HIV resistance by CCR532/32 mutation
CCR5 32/32 homozygous mutation 1% in Caucasian populationNo CCR5 expressionNaturally protected from HIV-1 infection
Hutter et.al. N Engl J Med. 2009 Feb 12;360(7):692-8.
Long-term control of HIV by CCR5 Delta32/Delta32 stem-cell transplantation
CCR5-32/ 32BM Donor (HIV-)
Nearly 100% replacement with the CCR5 negative donor cells.HAART was discontinued after BM transplant.HIV RNA and DNA became undetectable at 68 days post-transplantand remained negative for 5 years.
Bone Marrow transplant
Acute Myeloid LeukemiaPatient (HIV+)
This “Berlin Patient”was cured from HIV.
http://www.nytimes.com/1998/06/21/magazine/the-berlin-patient.html?pagewanted=all
A novel HIV cure therapy
Develop a hematopoietic stem cell based gene therapy for long term
control or HIV cure by a single treatment
RNA interference (RNAi)
siRNA (20nt)
RNAi
CCR5 mRNAAAAAn
Induce sequence specificmRNA degradation
Remove CCR5 from cell surfaceInhibit HIV infection
Stable CCR5 knock down by RNAi to confer resistance to R5 tropic HIV-1 infection
Lentiviral vector
shRNA
CCR5mRNA
CCR5
Qin XF, An DS, Chen ISY, D Baltimore, PNAS, 2003
CCR5 shRNA (EGFP)
NOD/SCID Hu BLT mouseHuman CD34+
Stem cells
Irradiation
Modeling RNAi-mediated CCR5 knockdown
in NOD/SCID humanized BLT mouse
No shRNA (mCherry)
Efficient CCR5 down regulation in EGFP+ CD4+ T cells in the humanized BLT mouse model
Thy/Liv Bone Marrow Spleen Lymph Node Lung Small Intestine LPL
Shimizu. S et. al. Blood 2010
EGFP
mCherry
CCR5
HIV-1 NL4-3 (X4)HIV-1 NFNSX SL9 (R5)
CCR5 shRNAno shRNA
CCR5 tropic HIV-1
Selective advantage of EGFP+ CCR5 knock downCD4+ T cells in peripheral blood
Unpublished
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