Few effective therapies exist for the treatment of neurodegenerative diseases 
that have been characterized as protein misfolding disorders. Upregulation of 
heat shock proteins (Hsps) mitigates against the accumulation of misfolded, 
aggregation-prone proteins and synaptic dysfunction, which is recognized as an 
early event in neurodegenerative diseases. Enhanced induction of a set of Hsps 
in differentiated human SH-SY5Y neuronal cells was observed following 
co-application of celastrol and arimoclomol, compared to their individual 
application. The dosages employed did not affect cell viability or neuronal 
process morphology. The induced Hsps included the little studied HSPA6 
(Hsp70B'), a potentially neuroprotective protein that is present in the human 
genome but not in rat and mouse and hence is missing in current animal models of 
neurodegenerative disease. Enhanced induction of HSPA1A (Hsp70-1), DNAJB1 
(Hsp40), HO-1 (Hsp32), and HSPB1 (Hsp27) was also observed. Celastrol activates 
heat shock transcription factor 1 (HSF1), the master regulator of Hsp gene 
transcription, and also exhibits potent anti-inflammatory and anti-oxidant 
activities. Arimoclomol is a co-activator that prolongs the binding of activated 
HSF1 to heat shock elements (HSEs) in the promoter regions of inducible Hsp 
genes. Elevated Hsp levels peaked at 10 to 12 h for HSPA6, HSPA1A, DNAJB1, and 
HO-1 and at 24 h for HSPB1. Co-application of celastrol and arimoclomol induced 
higher Hsp levels compared to heat shock paired with arimoclomol. The 
co-application strategy of celastrol and arimoclomol targets multiple 
neurodegenerative disease-associated pathologies including protein misfolding 
and protein aggregation, inflammatory and oxidative stress, and synaptic 
dysfunction.