Lactate Suppresses Retroviral Transduction in Cervical Epithelial Cells through DNA-PKcs Modulation

Waldemar Wagner,Katarzyna Sobierajska,Katarzyna Dominika Kania,Wojciech Michał Ciszewski,Edyta Paradowska

doi:10.3390/ijms222413194

Abstract

Recently, we have shown the molecular basis for lactate sensing by cervical epithelial cells resulting in enhanced DNA repair processes through DNA-PKcs regulation. Interestingly, DNA-PKcs is indispensable for proper retroviral DNA integration in the cell host genome. According to recent findings, the mucosal epithelium can be efficiently transduced by retroviruses and play a pivotal role in regulating viral release by cervical epithelial cells. This study examined the effects of lactate on lentiviral transduction in cervical cancer cells (HeLa, CaSki, and C33A) and model glioma cell lines (DNA-PKcs proficient and deficient). Our study showed that L- and D-lactate enhanced DNA-PKcs presence in nuclear compartments by between 38 and 63%, which corresponded with decreased lentiviral transduction rates by between 15 and 36%. Changes in DNA-PKcs expression or its inhibition with NU7441 also greatly affected lentiviral transduction efficacy. The stimulation of cells with either HCA1 agonist 3,5-DHBA or HDAC inhibitor sodium butyrate mimicked, in part, the effects of L-lactate. The inhibition of lactate flux by BAY-8002 enhanced DNA-PKcs nuclear localization which translated into diminished lentiviral transduction efficacy. Our study suggests that L- and D-lactate present in the uterine cervix may play a role in the mitigation of viral integration in cervical epithelium and, thus, restrict the viral oncogenic and/or cytopathic potential.

Highlights

Vaginal and ectocervical microbiota of the female genital tract (FGT) protects against pathogen colonization through the competition for adherence, the production of antimicrobial substances, and the secretion of high amounts of lactate
In the step, we evaluated the effects of dihydroxybenzoic acid (DHBA) (HCA1 agonist), sodium butyrate, and lactate to confirm whether the observed stimulatory effects of lactate on DNA-PKcs depend on extracellular lactate action, intracellular lactate action, or both
Our study demonstrated that changes in hydroxycarboxylic acid receptor 1 (HCA1) receptor expression or the stimulation of cervical epithelial cells with receptor ligands L-lactate or 3,5-dihydroxybenzoic acid induced the nuclear translocation of DNA-PKcs, which translated into a higher DNA repair rate [2,10]

Summary

Introduction

Vaginal and ectocervical microbiota of the female genital tract (FGT) protects against pathogen colonization through the competition for adherence, the production of antimicrobial substances, and the secretion of high amounts of lactate. We have reported the lactate-driven mechanisms by which lactate under physiological conditions modulates the activity of DNA repair machinery of the cervical epithelial cells. These pathways include the stimulation of surface-specific lactate hydroxycarboxylic acid receptor 1 (HCA1/GPR81) and the decrease of nuclear chromatin compactness by the inhibition of HDAC (histone deacetylase) [2,3]. HCA1 belongs to the G-protein-coupled receptor family, and when coupled to a Gi-protein, initiates two downstream signaling cascades (cAMP and Erk1/2 pathways) upon activation by its natural ligands: L-lactate, Dlactate, or dihydroxybenzoic acid (DHBA) [2,4]. Cellular lactate influx/efflux is dependent on the activity of monocarboxylate transporters (MCTs 1–4), directed by substrate and proton concentration gradients [9]

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