The long noncoding RNA (lncRNA) NEAT1 (nuclear enriched abundant transcript 1) 
is the architectural component of nuclear paraspeckles, and it has recently 
gained considerable attention as it is abnormally expressed in pathological 
conditions such as cancer and neurodegenerative diseases. NEAT1 and paraspeckle 
formation are increased in cells upon exposure to a variety of environmental 
stressors and believed to play an important role in cell survival. The present 
study was undertaken to further investigate the role of NEAT1 in cellular stress 
response pathways. We show that NEAT1 is a novel target gene of heat shock 
transcription factor 1 (HSF1) and is up-regulated when the heat shock response 
pathway is activated by sulforaphane (SFN) or elevated temperature. HSF1 binds 
specifically to a newly identified conserved heat shock element in the NEAT1 
promoter. In line with this, SFN induced the formation of NEAT1-containing 
paraspeckles via an HSF1-dependent mechanism. HSF1 plays a key role in the 
cellular response to proteotoxic stress by promoting the expression of a series 
of genes, including those encoding molecular chaperones. We have found that the 
expression of HSP70, HSP90, and HSP27 is amplified and sustained during heat 
shock in NEAT1-depleted cells compared with control cells, indicating that NEAT1 
feeds back via an unknown mechanism to regulate HSF1 activity. This 
interrelationship is potentially significant in human diseases such as cancer 
and neurodegenerative disorders.