title: Translesion Synthesis DNA Polymerase Kappa Is Indispensable for DNA Repair Synthesis in Cisplatin Exposed Dorsal Root Ganglion Neurons.
abstract: In the peripheral nervous system (PNS) in the absence of tight blood barrier, neurons are at increased risk of DNA damage, yet the question of how effectively PNS neurons manage DNA damage remains largely unanswered. Genotoxins in systemic circulation include chemotherapeutic drugs that reach peripheral neurons and damage their DNA. Because neurotoxicity of platinum-based class of chemotherapeutic drugs has been implicated in PNS neuropathies, we utilized an in vitro model of Dorsal Root Ganglia (DRGs) to investigate how peripheral neurons respond to cisplatin that forms intra- and interstrand crosslinks with their DNA. Our data revealed strong transcriptional upregulation of the translesion synthesis DNA polymerase kappa (Pol κ), while expression of other DNA polymerases remained unchanged. DNA Pol κ is involved in bypass synthesis of diverse DNA lesions and considered a vital player in cellular survival under injurious conditions. To assess the impact of Pol κ deficiency on cisplatin-exposed DRG neurons, Pol κ levels were reduced using siRNA. Pol κ targeting siRNA diminished the cisplatin-induced nuclear Pol κ immunoreactivity in DRG neurons and decreased the extent of cisplatin-induced DNA repair synthesis, as reflected in reduced incorporation of thymidine analog into nuclear DNA. Moreover, Pol κ depletion exacerbated global transcriptional suppression induced by cisplatin in DRG neurons. Collectively, these findings provide the first evidence for critical role of Pol κ in DNA damage response in the nervous system and call attention to implications of polymorphisms that modify Pol κ activity, on maintenance of genomic integrity and neuronal function in exogenously challenged PNS.
authors.affiliation: Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, 77555, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhuo
authors.affiliation: Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, 77555, USA.
authors.forename: Murat F
authors.initials: MF
authors.lastname: Gorgun
authors.affiliation: Department of Surgery, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, 77555, USA. elenglan@utmb.edu.
authors.forename: Ella W
authors.initials: EW
authors.lastname: Englander
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity*; D002478:Cells, Cultured; D002945:Cisplatin / Q000633:toxicity*; D004260:DNA Repair / Q000187:drug effects / Q000502:physiology*; D004259:DNA-Directed DNA Polymerase / Q000096:biosynthesis*; D005727:Ganglia, Spinal / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D018014:Gene Transfer Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics; D000099270:Y-Family DNA Polymerases
chemical_list: D000970:Antineoplastic Agents; D002945:Cisplatin; D004259:DNA-Directed DNA Polymerase; D034741:RNA, Small Interfering; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases
keywords: Cisplatin; DNA damage; DNA polymerase kappa (Pol κ); Dorsal root ganglion (DRG); Nucleotide excision repair (NER); Peripheral nervous system (PNS); Translesion synthesis (TLS)