Fig. 2

Extracellular Tau modulates the formation of TKS5-mediated podosome clusters in microglia. A Microglia rearrange the podosome differently at frontal lamellipodia such as podosome belts, clustered podosome, and single podosome, for the adherence to the substratum by membrane-associated actin polymerization. B, C Western blot analysis and relative fold change showed no significant changes in the expression of TKS5 protein upon various Tau exposure and ADP treatment in microglia (n = 3). D IF study revealed that microglia form various rearrangements of podosome upon exposure to extracellular Tau species and ADP. Among all structures, the podosome clusters were more evident in oligomer-treated microglia than in monomer exposure (scale bar 10 μm). E The clustered podosome accumulated by 20% more in lamellipodia upon Tau oligomers exposure, similar to ADP and cell control. (No. of experiment = 3) (n = 28). F While, The amount of single podosome arrangement in microglia remains unaltered among various Tau-treated groups. (No. of experiment = 3) (n = 28) G The podosome belts containing cells remain unaltered in Tau-induced migratory microglia. (No. of experiment = 3) (n = 28). H Furthermore, the TKS5 intensity of uropod was decreased in Tau oligomer-induced microglia, which may signify the rapid actin and actin-associated protein turnover from the rear end towards lamella upon migration. (No. of experiment = 3) (n = 50). I, J The time-dependent IF study showed that the extracellular Tau oligomers induced the accumulation of clustered podosome in microglial lamellipodia (scale bar 10 μm). Then, the quantification of microscopic images revealed that the TKS5 intensity was increased during the oligomers exposure from 6 h, compared to cell control. (No. of experiment = 3) (n = 40). K Further, the clustered podosome-containing microglial population have increased in a time-dependent manner in Tau oligomers-exposed microglia than to untreated cells. (No. of experiment = 3) (n = 10)