V-set and transmembrane domain containing 2 （VSTM2L） is a novel modulator of HN neuroprotective activity. VSTM2L colocalizes with HN in distinct brain areas as well as in primary cultured neurons， where it plays a part in the modulation of neuronal viability. When tested in HN neuroprotection bioassays， VSTM2L acts as a potent antagonist of HN neuroprotective activity. The VSTM2L protein is the first example of a secreted antagonist of HN and may have a role in the modulation of HN biological functions.
