Podosome rings generate forces that drive saltatory osteoclast migration

Podosomes are dynamic, actin-containing adhesion structures that self-organize as rings in osteoclasts. We observe that podosome rings generate tension forces and that osteoclasts migrate by periodically moving toward the actin-containing structures. Actin dynamics thus not only correlate with the cell migration, but drive it

Potassium citrate prevents increased osteoclastogenesis resulting from acidic conditions: Implication for the treatment of postmenopausal bone loss - Fig 3

<p><b>A)</b> RANKL-mediated OC differentiation in acidic and neutral microenvironment. The bars represent the mean ± SEM of the total number of OC/cm² obtained from buffy-coat of four individuals and cultured at pH 7.4 and pH 6.9 with three different RANKL concentrations. Symbols (*) indicate statistically significant differences vs RANKL 50 ng/mL at pH 7.4. <b>B)</b> The representative pictures show that the size of TRAcP positive multinucleated cells and the differentiating potency of low RANKL concentrations are higher at pH 6.9 than at pH 7.4. Magnification x 10, Scale bar = 50 μm. <b>(C)</b> and <b>(D)</b> K citrate inhibits the OC differentiation induced at pH 6.9 by high (C: 50 ng/mL) and low (D: 0.5 ng/mL) RANKL doses. Results are expressed as a ratio between the number of OC counted in cultures treated with different K citrate concentrations and number of OC counted in the negative control (K citrate 0 mM, ratio = 1). The positive control is Alendronate 10^-5M. Mean ± SEM of data obtained from three different donors and two replicates for each condition. Symbols (*) indicate statistically significant differences vs negative control (pH 6.9, K citrate 0 mM, ratio = 1). In all histograms P values ≤ 0.05, ≤ 0.01 and ≤ 0.001 were highlighted by one, two or three symbols, respectively.</p