HSPA4 and Parkinson disease: Hsp40 is a co‐chaperone able to stimulate ATPase activity of Hsp70 (DnaK), which is protective in models of PD.[63, 64, 65] Our previous data already reported the upregulation of Hsp40 in SK‐N‐MC cells after incubation with a blackberry‐digested polyphenol extract.[66] Since these proteins often work in concert, the upregulation of Hsp40 transcripts can be suggestive of an Hsp40‐mediated activation of the regulatory mechanism of Hsp70, with ultimate neuroprotective effects.[67]