New 'Suicide' Molecule Halts Arthritis -- MEDICA - World Forum for Medicine

New 'Suicide' Molecule Halts Arthritis

Photo: Fingers swollen due to arthritis

The powerful molecule fighting
rheumatoide arthritis in mice is
called Casper the Ghost; © SXC

Whimsically referred to as Casper the Ghost, the stealthy molecule causes the immune cells to self-destruct. "This new therapy stopped the disease cold in 75 percent of the mice," lead author Harris Perlman reported. "The best part was we did not see any toxicity. This has a lot of potential for creating an entirely new treatment for rheumatoid arthritis."

Healthy immune cells are supposed to die after they attack an invading virus or bacteria. But in rheumatoid arthritis, the immune cells called macrophages live and go rogue. They proliferate in the blood, build up in the joints and invade cartilage and bone. Currently, there is no effective, nontoxic way to stop them, according to the researcher.

Perlman discovered that immune cells in rheumatoid arthritis are low in a critical molecule called Bim, whose job is to order the cells to self-destruct. To correct that shortage, Perlman developed an imitation of the molecule, called BH3 mimetic. When Harris injected his drug into mice with rheumatoid arthritis, it floated ghostlike into their macrophages and the misbehaving immune cells self destructed.

In his research, Harris showed the molecule could prevent the development of rheumatoid arthritis as well as trigger a remission of existing disease in mice. After the drug was injected in animals with the disease, joint swelling was reduced and bone destruction decreased.

Current treatments for rheumatoid arthritis include low-level chemotherapy and steroids. These are not always effective, however, the researcher argues, and they are frequently accompanied by side effects. A newer class of therapy, which is sometimes used in combination with chemotherapy and steroids, is biologic response modifiers. These are antibodies or other proteins that reduce the inflammation produced by the hyperactive immune cells. These biologics do not work for everyone, though, and can be associated with side effects including the risk of infection. Perlman said the next step is to develop nanotechnology for a more precise method of delivering the drug.; Source: Northwestern University