PARP‐1 mediated repairing of bupivacaine‐induced neuron oxidative DNA damage needs the co‐expression of xeroderma pigmentosum D
Authors: Zhao Wei , Liu Zhongjie , Luo Jiaming , Xia Zhengyuan , Xu Shiyuan 
Published: April 2020

BACKGROUNDThe local Anesthetic bupivacaine has been widely used in clinical Anesthesia, but its neurotoxicity has been frequently reported, implicating cellular oxidative DNA damage as the major underlying mechanism. However, the mechanism governing the repairing of bupivacaine‐induced DNA damage and neurotoxicity is unknown.METHODSNeurotoxicity was established by exposing SH‐SY5Y cells to 1.5mM bupivacaine. Then, iTRAQ proteomic analysis was used to explore which repair enzymes and pathways are involved in the repair of neuronal oxidative DNA damage. By analyzing the STRING version 11.0 database, the bioinformatics relationship between key repair enzymes was tracked. Subsequently, immunofluorescence co‐localization and immunoprecipitation were used to investigate the interaction between key repair enzymes.RESULTSThe iTRAQ proteomic screening showed that Poly [ADP‐ribose] polymerase 1 (PARP‐1) from the base excision repair pathway was closely involved in the repair of oxidative DNA damage induced by bupivacaine, and inhibition of PARP‐1 expression significantly aggravated bupivacaine induced DNA damage and apoptotic cell death. By contrast, the XPD (xeroderma pigmentosum D) which is another key protein of the nucleic acid excision repair pathway had no direct effect on the repair of oxidative DNA damage induced by bupivacaine. Interestingly, our results showed that there was an interaction and co‐expression between PARP‐ 1 and XPD. After inhibiting XPD, PARP‐1 expression was significantly reduced. Inhibition of either XPD or PARP‐1 alone could increase DNA damage induced by bupivacaine. However, inhibition of both XPD and PARP‐1 together did not further increase the DNA damage.CONCLUSIONSPARP‐1 may repair oxidative DNA damage induced by bupivacaine through XPD‐mediated interactions.Support or Funding InformationThe work was supported by the grants from the National Natural Science Foundation of China (No. 81701464) and the Natural Science Foundation of Guangdong province, China(2017A030313627).Bupivacaine may cause oxidative DNA damage to neurons. The damaged DNA activates the repair mechanism that is largely unknown. Our study showed that both PARP‐1 and XPD are closely involved in the oxidative DNA damage of neurons caused by bupivacaine. Interestingly, we also found that there is an interaction between the two key repair enzymes, not just to complete the DNA repair alone. Further, our data suggest that PARP‐1 may repair oxidative DNA damage through XPD‐mediated interactions.Figure 1In the (PJ34+Bup) group DNA damage was aggravated(A, B; D, E), meanwhile, the apoptotic index increased (A, C). There is no evidence confirming an interaction between PARP‐1 and ERCC2/XPD(F). However, immunofluorescence staining showed the colocalization of XPD and PARP‐1 (G). The XPD was not affected after inhibiting PARP‐1(H, I). However, after inhibiting XPD, PARP‐1 expression was significantly reduced (H, J). After inhibiting XPD and PARP‐1 together, the DNA damage did not increase further(H, K).Figure 2