{"id":28038,"date":"2015-11-10T12:50:52","date_gmt":"2015-11-10T17:50:52","guid":{"rendered":"http:\/\/sciencebusiness.technewslit.com\/?p=28038"},"modified":"2016-06-11T12:21:12","modified_gmt":"2016-06-11T16:21:12","slug":"usc-biotech-edit-genes-in-stem-cells-for-hiv-therapy","status":"publish","type":"post","link":"https:\/\/technewslit.com\/sciencebusiness\/?p=28038","title":{"rendered":"USC, Biotech Edit Genes in Stem Cells for HIV Therapy"},"content":{"rendered":"
\"Paula<\/a>
Paula Cannon (University of Southern California)<\/figcaption><\/figure>\n

10 November 2015. A lab at University of Southern California and biotechnology company developed a technique for editing genomes in blood-forming stem cells as a potential treatment for HIV infection. The team from the lab of USC medical school professor Paula Cannon<\/a> and Sangamo BioSciences<\/a> in Richmond, California published its findings yesterday in the journal Nature Biotechnology<\/a><\/em> (paid subscriptions required).<\/p>\n

The USC\/Sangamo team are seeking more effective techniques to edit genomes in human hematopoietic stem and progenitor cells, or HSPCs, the early-stage cells that transform into blood cells. “Gene therapy using HSPCs has enormous potential for treating HIV and other diseases of the blood and immune systems,” says Cannon in a university statement<\/a>. “And using genome editing techniques now allows us to make very precise changes that could repair genetic mutations, the gene typos, that can cause disease.<\/p>\n

Being able to edit the genes in these blood-forming stem cells makes it possible to deactivate genes that create receptors for viral diseases, such as HIV, as well as immune deficiencies, and blood disorders. But these early-stage cells are also simple and primitive, with few accessible targets for editing.<\/p>\n

Cannon’s lab is partnering with Sangamo to adapt the company’s genome-editing technology using zinc-finger nucleases<\/a>, synthetic enzymes that can modify DNA sequences, including corrections or insertions. These enzymes, with a hydrocarbon and zinc chemistry<\/a>, branch out in finger-like protrusions that bind with DNA molecules. Sangamo says it engineers the proteins to predictably and consistently bind with longer DNA sequences.<\/p>\n

In addition, zinc-finger nucleases need only a brief, temporary expression to perform their editing functions, making them useful for modifying the genomes, but not otherwise damaging the stem cells. The researchers delivered zinc-finger nucleases to the genomes of human blood-forming stem cells with messenger RNA, signaling proteins that send genetic instructions, and electroporation<\/a>, millisecond electrical pulses creating temporary pores in the cells’ membranes.<\/p>\n

The editing enzymes targeted the CCR5 gene<\/a> that encodes a receptor in T-cells, white blood cells in the immune system, that when damaged allow HIV viruses to enter the host cells. The researchers used adeno-associated viruses to deliver a healthy replacement DNA sequence, along with the gene editing enzymes. Adeno-associated viruses<\/a> are naturally occurring microbes that\u00a0<\/span>can infect cells, but do not integrate with the cell\u2019s genome nor cause disease.<\/p>\n

The team found the edited genes succeed in 17 to 26 percent of peripheral blood stem cells and 19 to 43 percent of blood-forming stem cells from the liver, which the researchers say is a high rate of efficiency for these techniques. Results also show the edited stem cells, when\u00a0transplanted into immune-deficient mice, transform into functioning blood cells while retaining the stem cell edits.<\/p>\n

Sangamo Biosciences is also collaborating with University of Pennsylvania medical school in adapting its gene-editing techniques to HIV therapies. As reported last year in Science & Enterprise<\/a>, a clinical trial shows the company\u2019s gene-editing technology can engineer the immune cells of HIV-positive patients to resist infection and decrease their viral loads.<\/p>\n

Read more:<\/p>\n