SPHK1 and Alzheimer disease: These data support the inflammatory contribution of glial cells in Sphk1–S1P signaling, whereas neuronal Sphk1 has been reported to demonstrate contradictory functions, i.e., neuronal Sphk1 regulates microglial phagocytic functions and COX2 activity, and decreased expression of this signaling has been observed in the AD pathology [55].