Haematopoetic Stem Cells

New results from the laboratory of Camilla Forsberg at the Institute for the Biology of Stem Cells, University of Santa Cruz, California are beginning to unravel the mechanisms by which transplanted haematopoietic stem cells (HSCs) localise to the bone marrow niche. HSC transplants are a common treatment for various illnesses including certain blood cancers and their correct localisation is critical to the successful function of grafted cells. In their study, Smith-Berdan et al. investigated the guidance molecule Robo4 and discovered its role as a HSC-specific adhesion molecule by facilitating the adhesion of HSCs to the bone marrow niche. They demonstrate that HSCs lacking Robo4 have reduced capacity to localise within the bone marrow following transplantation, drastically reducing long term reconstitution. They demonstrate that Robo4 exerts its effects in cooperation with the Cxcr4 protein, and that inhibition of both these proteins mediates HSC mobilisation. The identification of putative therapeutic targets in HSC transplantation therapy will no doubt lead to greater success of this strategy by enabling more specific integration of grafted cells.

By Stuart P. Atkinson

UNAIDS (Joint United Nations Programme on HIV and AIDS) estimated that at the end of 2009 33.3 million people were living with HIV, and that in the same year there had been 1.8 million AIDS-related deaths and 2.6 million new infections (UN Millennium Goals report 2010). The benefits of anti-retroviral therapy (ART) have been demonstrated in some patients, however, resistance can develop, therapy is expensive (meaning that the vast majority of sufferers cannot have access) and multiple organ toxicity occurs with long-term use. Therefore, a safer and more cost effective therapy is clearly required. There have been reported cases of patients living with long-term HIV infection without progression to AIDS and in other cases patients seem to have some degree of immunity when exposed to the virus – both scenarios suggest a possible genetic influence on an individual’s response to HIV infection.

Potential Stem Cell Therapy for HIV Reported

From Nature Biotech

An advance online article from Nature Biotechnology reports the creation of genetically modified human hematopoietic stem/progenitor cells which when injected and engrafted in mice confer some resistance to HIV.   Specifically, Holt et al disrupted CCR5, the major HIV-1 co-receptor using engineered zinc-finger nucleases (ZFNs) and compared to control mice, the mice which received such cells showed significantly lower HIV-1 levels.

By Carla B. Mellough

The secret to eternal youth has been under pursuit for centuries. But now, results reported in Nature by a group at Harvard University shed new light on just how the ageing process might be co-ordinated across tissues and, astonishingly, that we may be able to reverse it (Mayack et al., 2010).