Micro-contact Printing Coupled With MS For Single Cell Lipids Analysis

Single-cell analysis is very important in several research fieldssuch as early diagnosis,drug screening,phenotypic diversity,transcription events for the heterogeneity of individual cells has been well-accepted.However,restricted by the size and low content of single cell,current studies have encountered challenges in high-throughput,multicomponent analysis.Here,we developed a methodology for high-throughput single cells patterning and phospholipids analysis through surface-printed microdot array chip coupled with MALDI-MS.The poly-L-lysine(PLL)used as ink molecule was printed on the oxygen plasma processed indium tin oxide(ITO)-coated glass slide to form microdot array by micro-contact printing technology.The cell array formed on the PLL microarray with single cell capture efficiency of about 40%(the cell capture efficiency is 70%),were analyzed through MALDI-MS.Twelve phospholipids were detected at the single-cell level and the structures were further confirmed by MS/MS.The MALDI mass spectrometry imaging(MALDI-MSI)of selected ions showed a conformity with the cell array.The relative signal intensity data of selected ions was extracted from every pixels in the image within several minutes.The heterogeneitybetween individual cells was revealed from the relative signal intensityof the phospholipids.Comparing to the existing related approaches,high-throughput,quick measurement and multicomponent single-cell analysishas been realized by our method.Through different ink molecules used for micro-contact printing,the established platform might have potential to capture and analyze specific cells.Besides,great importance has been attached to screen anti-tumor drugs for these years.The mechanism study of new anti-tumor drugs is a vital factor for the drugs application.A marine natural product GUO-1236,which is used in this paper,has a good antitumor activity against tumor cells,especially for lung cancer A549 cells.But its specific mechanism for anti-tumor has not been reported.Using the method of proteomics,the protein samples were analyzed by 2D nano-UPLC MSE.60 significant differential proteins were obtained through analyzing the control group and the drug-treated group.Among the significant differential proteins,9 proteins were up-regulated and 51 down regulated.11 histones were detected in the significant differential proteins.The GO analysis of differential protein revealedthat GUO-1236 played an important role inchromatin assembly biological process,nucleosome,and cytoskeletal protein binding effect.What's more,SP_PIR pathway analysis showed the influence of acetylation far exceeds that of other post-translational modifications.Some binding sites were analyzed in WesternBlot experiment to verify the acetylation of histone.The results indicated that GUO-1236 acted as histone deacetylation inhibitorin anti-proliferation of A549 cell.