Effects of Different Phosphatidylglycerol Species on the Proliferation of Primary Mouse Keratinocytes

Abstract

Evidence is growing that phosphatidylglycerol (PG) plays a key role in modulating keratinocyte proliferation, as we have previously shown that liposomes derived from egg PG inhibit the proliferation of rapidly dividing cells and stimulate the growth of slowly proliferating keratinocytes. To determine the species of PG most effective at modulating proliferation of primary mouse keratinocytes, primary mouse keratinocytes were treated with liposomes composed of different PG species, and proliferation was measured as [3H]thymidine incorporation into DNA. PG species containing polyunsaturated fatty acids were effective at inhibiting rapidly proliferating keratinocytes, whereas PG species with monounsaturated fatty acids were effective at promoting proliferation in slowly dividing keratinocytes. Thus, palmitoyl, arachidonyl PG (16:0, 20:4, with the first number representing the number of carbon atoms in the fatty acid and the second, the number of double bonds), palmitoyl, linoleoyl PG (16:0,18:2), dilinoleoyl PG (18:2,18:2) and soy PG (a PG mixture with a large percentage of polyunsaturated fatty acids) were particularly effective at inhibiting proliferation in rapidly dividing keratinocytes. Palmitoyl, oleoyl PG (16:0, 18:1) and dioleoyl PG (18:1, 18:1) were especially effective proproliferative PG species. This result suggests that different PG species may signal to diverse effector enzymes to differentially affect keratinocyte proliferation and may be useful for treating skin diseases characterized by excessive or insufficient proliferation. (Supported by NIH grants #AR45212 and AR55022.)