Fig. 2

Aβ1-42-mediated reduction of MerTK expression is associated with increased intracellular Ca²⁺ level compared to treatment with ionomycin A or thapsigargin. a Intracellular Ca²⁺ images were obtained by Fluo-3AM method at 8 h after treatment with either the vehicle only (−), ionomycin A (4 μM), thapsigargin (2 μM), or 10 μM Aβ1-42 in THP-1 macrophages. b Histogram showing the ratio of intracellular Ca²⁺ levels to vehicle-treated group. c THP-1 cells were incubated with either the vehicle only (−), ionomycin A (4 μM), thapsigargin (2 μM), or Aβ1-42 (10 μM) for 8 h. d Densitometric quantification of analyses of c showing levels of MerTK protein. e THP-1 cells were pretreated with EGTA (0.5 mM) for 30 min followed by incubation with either the vehicle only (−) or Aβ1-42 (10 μM) for 8 h. Total cell lysates were examined for MerTK via immunoblot. MerTK expression was decreased when intracellular Ca²⁺ levels were increased by ionomycin A, thapsigargin, or Aβ1-42. In contrast, the Aβ1-42-mediated decrease of MerTK protein was attenuated by depletion of Ca²⁺ with EGTA. Results are representative of three independent experiments. f Densitometric quantification of analyses of e showing levels of MerTK protein. All data are presented as means ± SEM (n = 3). **P < 0.01, versus vehicle-treated samples; ^##P < 0.01, compared to Aβ1-42-treated samples. Aβ, amyloid-β; EGTA, ethylene glycol trtraacetic acid; MerTK, Mer tyrosine kinase