Limited expansion and improved survival of primary human beta-cells by adenoviral overexpression adaptorprotein IRS-2 and cell cycle regulating kinase cdk-4

Mass and function of pancreatic beta-cells in type II diabetes mellitus is not sufficient to maintain euglycemia, especially during the course of the disease. Therapeutic intervention to increase beta-cell growth and delay programmed cell death has the potential to improve glucose control without the need to administer exogenous insulin. The adaptorprotein IRS-2 has been shown to be essential for beta-cell survival and function and cdk-4 promotes cell cycle entry in beta-cells.

We examined whether adenoviral infection of human primary beta-cells with IRS-2 and cdk-4 increases survival and proliferation. Human primary beta-cells were maintained in culture as single cells or cellular aggregates for up to 4 weeks on different matrixes.

Overexpression of IRS-2 and cdk-4 could be achieved by adenoviral infection with an MOI of 10 to 50 and over-expression was maintained at for 48 to 72h post infection. Thus, primary beta-cells were infected every 4 days with IRS-2 or cdk-4 during culture. Overexpression of IRS-2 and cdk-4 in human primary beta-cells increased survival and insulin content of beta-cells during culture. However, overexpression of IRS-2 and cdk-4 was not sufficient for prolonged cultivation and expansion of beta-cells, which may require transient expression of other cell cycle dependent kinases such as Cyclin D1.

Supported by JDRF.