Acetylation-deacetylation of the transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2) regulates its transcriptional activity and nucleocytoplasmic localization.

Activation of Nrf2 by covalent modifications that release it from its inhibitor protein Keap1 has been extensively documented. In contrast, covalent modifications that may regulate its action after its release from Keap1 have received little attention. Here we show that CREB-binding protein induced acetylation of Nrf2, increased binding of Nrf2 to its cognate response element in a target gene promoter, and increased Nrf2-dependent transcription from target gene promoters. Heterologous sirtuin 1 (SIRT1) decreased acetylation of Nrf2 as well as Nrf2-dependent gene transcription, and its effects were overridden by dominant negative SIRT1 (SIRT1-H355A). The SIRT1-selective inhibitors EX-527 and nicotinamide stimulated Nrf2-dependent gene transcription, whereas resveratrol, a putative activator of SIRT1, was inhibitory, mimicking the effect of SIRT1. Mutating lysine to alanine or to arginine at Lys(588) and Lys(591) of Nrf2 resulted in decreased Nrf2-dependent gene transcription and abrogated the transcription-activating effect of CREB-binding protein. Furthermore, SIRT1 had no effect on transcription induced by these mutants, indicating that these sites are acetylation sites. Microscope imaging of GFP-Nrf2 in HepG2 cells as well as immunoblotting for Nrf2 showed that acetylation conditions resulted in increased nuclear localization of Nrf2, whereas deacetylation conditions enhanced its cytoplasmic rather than its nuclear localization. We posit that Nrf2 in the nucleus undergoes acetylation, resulting in binding, with basic-region leucine zipper protein(s), to the antioxidant response element and consequently in gene transcription, whereas deacetylation disengages it from the antioxidant response element, thereby resulting in transcriptional termination and subsequently in its nuclear export.

Intimate partner and nonpartner violence against pregnant women in rural Haiti.

OBJECTIVE: To examine the association between violence experienced by pregnant Haitian women in the previous 6 months and pregnancy-related symptom distress. METHODS: A total of 200 women seeking prenatal care at community health dispensaries in the Artibonite Valley were interviewed. RESULTS: Over 4 in 10 women (44.0%) reported that they had experienced violence in the 6 months prior to interview; 77.8% of these women reported that the violence was perpetrated by an intimate partner. Those who experienced intimate partner violence reported significantly greater pregnancy-related symptom distress (beta=0.23, P=0.001). No significant differences between violence perpetrated by family members or others and reporting of symptoms were observed (beta=0.06, P=0.38). CONCLUSION: The findings indicate the need to integrate violence screening, resources, and primary prevention into prenatal care in rural Haiti.

Multiple nuclear localization signals function in the nuclear import of the transcription factor Nrf2.

Nuclear factor erythroid 2-related factor 2 (Nrf2) mediates the transcriptional response of cells to oxidative stress and is translocated into the nucleus following, or concomitant with, its activation by electrophiles or reactive oxygen species. The mechanism of its translocation into the nucleus is not entirely elucidated. Here we have identified two novel nuclear localization signal (NLS) motifs in murine Nrf2, one located near the N-terminal region (amino acid residues 42-53) and the other (residues 587-593) located near the C-terminal region. Imaging of green fluorescent protein (GFP)-tagged Nrf2 revealed that mutation(s) in any of these sequences resulted in decreased nuclear fluorescence intensity compared with the wild-type Nrf2 when Nrf2 activation was induced with the electrophile tert-butylhydroquinone. The mutations also impaired Nrf2-induced transactivation of antioxidant response element-driven reporter gene expression to the same extent as the Nrf2 construct bearing mutation in a previously identified bipartite NLS that maps at residues 494-511. When linked to GFP or to GFP-PEPCK-C each of the novel NLS motifs was sufficient to drive nuclear translocation of the fusion proteins. Co-immunoprecipitation assays demonstrated that importins alpha5 and beta1 associate with Nrf2, an interaction that was blocked by the nuclear import inhibitor SN50. SN50 also blocked tert-butylhydroquinone-induced nuclear fluorescence of GFP-Nrf2 in cells transfected with wild-type GFP-Nrf2. Overall these results reveal that multiple NLS motifs in Nrf2 function in its nuclear translocation in response to pro-oxidant stimuli and that the importin alpha-beta heterodimer nuclear import receptor system plays a critical role in the import process.

The influence of power on HIV risk among pregnant women in rural Haiti.

Given that condom use is not directly under a woman's control, the sexual division of power may play an important role in sexual behavior among pregnant women. We assessed the influence of factors related to the theory of gender and power (e.g., relationship power, abuse history, and sexual communication) on sexual behavior (e.g., two or more partners in the year prior to pregnancy, condom use, condom-use intentions, and STI diagnosis) among 196 pregnant women recruited from five community dispensaries in rural Haiti. Results showed that gender and power factors significantly related to sexual behavior. Gender and power factors were most significant for condom use and intention to use condoms, accounting for 18 and 25% of the variance above and beyond HIV knowledge and demographic covariates, respectively. These results suggest the need to create prevention interventions that restore power imbalances, provide support for women suffering abuse, and strengthen communication skills.