Human placental laminin: Role in neuronal differentiation, cell adhesion and proliferation

ABSTRACT

Human placental extract has wound healing potential. Immuno-blots revealed presence of laminin in placentalextract (70 ± 0.257 lg/ml; n=3). It was purified using immuno-affinity chromatography. SDS-PAGE and SEHPLC indicated a188 kDa protein with some small peptides. Since placental laminin existed in its truncatedform, its roles in cellular migration, differentiation and wound healing were verified. Induction of cellularmigration and motility in rat fibroblasts were enhanced by placental laminin as observed from scratch woundassay. Promotion of neuronal differentiation of PC12 cells by placental laminin was observed by phase contrastmicroscopy. Confocal images showed presence of laminin on the cell surface and along the axonal processes.Significant interaction between integrin receptors and laminin responsible for cellular differentiation wasdemonstrated from co-localization experiments. Union between integrin receptor and its synthetic antagonistrevealed retarded pattern of neurite outgrowth in laminin treated cells. Animal model studies revealed fasterwound healing in the presence of placental laminin. Induction of re-epithelialization and angiogenesis inwound area by cellular proliferation and adhesion were observed. The cytokine levels showed an initial riseand gradual fall over the duration of wound healing on application of the fragmented laminin. Thus, roles ofplacental laminin in neuronal differentiation and wound healing were indicated.