ObjectiveTo investigate the target proteins directly bound by neochlorogenic acid （NA） and the molecular mechanisms that ameliorate the proliferation and inflammatory response of psoriatic keratinocytes.MethodsM5-induced HaCaT cells were used as a psoriatic keratinocyte proliferation and inflammatory cell model. The synthesized NA probe （NA-P） and NA prodrug were first evaluated for cell viability using a cell proliferation/toxicity assay kit-8（CCK-8）. The potency of NA and NA-P was evaluated in the safe concentration range， and the effects of 0-100 μmol·L^-1 NA and probe on M5-induced proliferation of HaCaT cells were detected using CCK8. The effects of 20， 40， and 80 μmol·L^-1 NA and 80 μmol·L^-1 NA probe on the expression of tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β）， interleukin-23 （IL-23）， and interleukin-17A （IL-17A） inflammatory factors were detected by enzyme-linked immunosorbent assay （ELISA）， and real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to measure the effects of NA on the mRNA expression of keratin 16 （K16） in HaCaT cells， S100 calcium-binding protein A9 （S100A9）， S100 calcium-binding protein A7 （S100A7）， IL-6， IL-17A， and chemokine 1 （CXCL1）. In vitro fluorescence labeling and competition experiments using NA probes were performed， and target protein angling and analysis using pull-down experiments combined with liquid chromatography-mass spectrometry （Pull-down/LC-MS/MS） were conducted. Target validation was performed using pull-down experiments combined with protein immunoblotting （Pull down-WB）， cellular heat transfer analysis combined with protein immunoblotting （CETSA-WB） experiments， and molecular docking. Finally， Real-time PCR was utilized to detect the effects of 20， 40， 80 μmol·L^-1 NA and 80 μmol·L^-1 NA probe on the mRNA expression of IL-1β， nucleotide-binding oligomeric structural domain-like receptor protein 3 （NLRP3）， apoptosis-associated speckled-like protein （ASC）， and cysteine protease-1 （Caspase-1） in HaCaT cells. Protein immunoblotting （Western blot） was used to detect the effects of phosphorylated p65 （p-p65）， p65， phosphorylated human nuclear factor-κB inhibitory protein α （p-IκBα）， human nuclear factor κB inhibitory protein α （IκBα）， and heat shock protein 90 （HSP90） expression.ResultsIn the 200 μmol·L^-1 safe concentration range， HaCaT cell proliferation， increased expression of TNF-α， IL-1β， IL-23， and IL-17A inflammatory factors， and increased mRNA expression of K16， S100A9， S100A7， IL-6， IL-17A， and CXCL1 were observed in the M5 group compared with the blank group. Cell proliferation in 5-100 μmol·L^-1 NA and NA-P groups was inhibited， and the expression of TNF-α， IL-1β， IL-23， and IL-17A inflammatory factors was decreased in the NA-L， NA-M， NA-H， and NA-P-H groups. The mRNA expression of K16， S100A9， S100A7， IL-6， IL-17A， and CXCL1 was decreased （P<0.05）. High-confidence targets were screened for HSP90 protein by Pull-down/LC-MS/MS using 200 μmol·L^-1 NA competing with 100 μmol·L^-1 NA-P. Compared with that in the blank group， the mRNA expression of NLRP3， IL-1β， ASC， and Caspase-1， as well as the expression of p-p65/p65， p-IκBα/IκBα， and HSP90 protein， were increased in HaCaT cells in the M5 group （P<0.05）. Compared with that in the M5 group， the mRNA expression of NLRP3， IL-1β， ASC， and Caspase-1 of cells in the NA-L group， the NA-M group， the NA-H group， and the NA-P-H group was decreased （P<0.05）. p-p65/p65 and p-IκBα/IκBα were decreased in the NA-M and NA-H groups （P<0.05）， and there was no change in HSP90 protein. Pull down-WB showed that NA could directly target HSP90 protein， and NA binding to HSP90 protein enhanced its thermal stability. Molecular docking of NA with HSP90 family proteins HSP90AA1， HSP90B1， and HSP90AB1 all resulted in highly stable binding.ConclusionNA can inhibit the proliferation and inflammatory response of psoriatic keratinocytes by a mechanism that may be achieved by targeting HSP90 to modulate the NF-κB/NLRP3 signaling pathway.

neochlorogenic acid;HSP90;nuclear factor-κB/nucleotide-binding oligomeric structural domain-like receptor protein 3（NF-κB/NLRP3） signaling pathway;proliferation of psoriatic keratinocyte;inflammation