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

A Man is Cured of AIDS

Photo Credit: http://pozmagazine.tumblr.com/

HIV entry into CD4 T lymphocytes is mediated by the chemokine CCR5 receptor

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

Develop anti-HIV gene therapy strategies using autologous hematopoietic stem cells

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

Mr. Timothy Brown “Berlin Patient” The man was cured of HIV

I willI willI promise to develop a cure therapy for HIV patients!