SFRP1 modulates astrocyte-to-microglia crosstalk in acute and chronic neuroinflammation

Neuroinflammation is a common feature of many neurodegenerative diseases. It fosters a dysfunctional neuron–microglia–astrocyte crosstalk that, in turn, maintains microglial cells in a perniciously reactive state that often enhances neuronal damage. The molecular components that mediate this critical communication are not fully explored. Here, we show that secreted frizzled-related protein 1 (SFRP1), a multifunctional regulator of cell-to-cell communication, is part of the cellular crosstalk underlying neuroinflammation. In mouse models of acute and chronic neuroinflammation, SFRP1, largely astrocyte-derived, promotes and sustains microglial activation, and thus a chronic inflammatory state. SFRP1 promotes the upregulation of components of the hypoxia-induced factor-dependent inflammatory pathway and, to a lower extent, of those downstream of the nuclear factor-kappa B. We thus propose that SFRP1 acts as an astrocyte-to-microglia amplifier of neuroinflammation, representing a potential valuable therapeutic target for counteracting the harmful effect of chronic inflammation in several neurodegenerative diseases.
This work was supported by grants from the Spanish AEI (BFU2013-43213-P; BFU2016-75412-R with FEDER support and PID2019-104186RB-I00), Fundacion Tatiana Perez de Guzman el Bueno and CIBERER to PB. JRC (BES-2011-047189), GP (BES-2017- 080318) and MIM (BES-2014-068797) were supported by FPI fellowships from the AEI. We also acknowledge a CBM Institutional Grant from the Fundacion Ramon Areces.