Atomic force microscopy investigations of fibronectin and α5β1-integrin signaling in neuroplasticity and seizure susceptibility in experimental epilepsy

•The functional significance of integrin signaling in epilepsy is unclear.•Atomic force microscopy was utilized to identify alterations in fibronectin-integrin signaling in epileptic dentate gyrus granule cells.•There were striking changes in the mechano-sensitive properties of granule cells in epilepsy.•Experimental epileptogenesis was significant reduced in mice treated with integrin blockers.•Integrins are involved in epileptogenesis and may offer new targets for the prevention and treatment of epilepsy. Extracellular matrix protein-integrin interaction on neurons plays an important role in the development of neuroplasticity in the brain. However, the role of fibronectin-integrin signaling in epilepsy is elusive. Here, we examined the functional role of fibronectin-integrin signaling by utilizing a combination approach involving atomic force microscopy (AFM), immunocytochemistry, and pharmacology in epileptic mouse dentate gyrus granule cells (DGGCs). There was marked increase in the fibronectin receptor α5β1-integrin staining intensity in DGGCs in epileptic mice. In the AFM study, the unbinding force and binding probability between the fibronectin-coated AFM probe and the membrane integrins were significantly reduced; while the cell stiffness was strikingly increased in epileptic DGGCs. Pretreatment with α5β1-integrin monoclonal antibody partially reversed this membrane dysfunction. In patch-clamp recordings, fibronectin significantly inhibited GABA current, while RGD, which is known to disrupt fibronectin-integrin-dependent cell adhesive events, strikingly enhanced GABA tonic currents in DGGCs in hippocampal slices. The α5β1-integrin antibody significantly reduced 4-aminopyridine-induced epileptiform discharges in brain slices. In systemic behavioral studies, susceptibility to hippocampus kindling epileptogenesis was significantly attenuated in mice treated with RGD or β1-integrin antibody. These pilot studies provide new insights on the functional role of integrin receptor signaling in epileptogenesis and may help identify novel targets for the prevention and treatment of epilepsy.