CD44 and Alzheimer disease: Heparan sulfate proteoglycan, a highly conserved protein expressed in many species and tissues, is involved in basic cellular processes, such as cell proliferation, cell growth, axon guidance, and synapse formation (Rawson et al., 2005; Stewart and Sanderson, 2014; Jiao et al., 2016; Condomitti and de Wit, 2018), and is highly related to AD pathology.