Listeria monocytogenes requires DHNA-dependent intracellular redox homeostasis facilitated by Ndh2 for survival and virulence.

Listeria monocytogenes is a remarkably well-adapted facultative intracellular pathogen that can thrive in a wide range of ecological niches. L. monocytogenes maximizes its ability to generate energy from diverse carbon sources using a respiro-fermentative metabolism that can function under both aerobic and anaerobic conditions. Cellular respiration maintains redox homeostasis by regenerating NAD+ while also generating a proton motive force. The end products of the menaquinone (MK) biosynthesis pathway are essential to drive both aerobic and anaerobic cellular respirations. We previously demonstrated that intermediates in the MK biosynthesis pathway, notably 1,4-dihydroxy-2-naphthoate (DHNA), are required for the survival and virulence of L. monocytogenes independent of their role in respiration. Furthermore, we found that restoration of NAD+/NADH ratio through expression of water-forming NADH oxidase could rescue phenotypes associated with DHNA deficiency. Here, we extend these findings to demonstrate that endogenous production or direct supplementation of DHNA restored both the cellular redox homeostasis and metabolic output of fermentation in L. monocytogenes. Furthermore, exogenous supplementation of DHNA rescues the in vitro growth and ex vivo virulence of L. monocytogenes DHNA-deficient mutants. Finally, we demonstrate that exogenous DHNA restores redox balance in L. monocytogenes specifically through the recently annotated NADH dehydrogenase Ndh2, independent of its role in the extracellular electron transport pathway. These data suggest that the production of DHNA may represent an additional layer of metabolic adaptability by L. monocytogenes to drive energy metabolism in the absence of respiration-favorable conditions.

Duration of Time CD4/CD8 Ratio is Below 0.5 is Associated with Progression to Anal Cancer in Patients with HIV and High-Grade Dysplasia.

BACKGROUND: A CD4/CD8 ratio < 0.5 is associated with increased risk of advanced anal disease (AAD) but it is unknown if duration below 0.5 matters. The purpose of this study was to determine if duration of a CD4/CD8 ratio < 0.5 is associated with increased risk of invasive anal cancer (IC) in people living with HIV and high-grade dysplasia (HSIL). METHODS: This single institution, retrospective study used the University of Wisconsin Hospital and Clinics Anal Dysplasia and Anal Cancer Database. Patients with IC versus HSIL alone were compared. Independent variables were mean and percentage of time the CD4/CD8 ratio was < 0.5. Multivariate logistic regression was performed to estimate the adjusted odds of anal cancer. RESULTS: We identified 107 patients with HIV infection and AAD (87 with HSIL, 20 with IC). A history of smoking was significantly associated with the development of IC (95% in patients with IC vs. 64% in patients with HSIL; p = 0.015). Mean time the CD4/CD8 ratio was < 0.5 was significantly longer in patients with IC compared with patients with HSIL (7.7 years vs. 3.8 years; p = 0.002). Similarly, the mean percentage of time the CD4/CD8 ratio was < 0.5 was higher in those with IC versus those with HSIL (80% vs. 55%; p = 0.009). On multivariate analysis, duration CD4/CD8 ratio was < 0.5 was associated with increased odds of developing IC (odds ratio 1.25, 95% confidence interval 1.02-1.53; p = 0.034). CONCLUSIONS: In this retrospective, single-institution study of a cohort of people living with HIV and HSIL, increasing duration the CD4/CD8 ratio was < 0.5 was associated with increased odds of developing IC. Monitoring the number of years the CD4/CD8 ratio is < 0.5 could inform decision making in patients with HIV infection and HSIL.

Analysis of >15 000 Solid Organ Transplant Recipients Reveals Nonanal Genitourinary HPV-related Disease as Highest Risk Predictor for Anal Squamous Intraepithelial Lesions/Anal Cancer.

BACKGROUND: Solid organ transplantation is a risk predictor for virally-mediated anal squamous intraepithelial lesions and cancer (anal disease). Precancerous squamous intraepithelial lesions can be detected by screening, and treatment may prevent cancer progression. Screening recommendations are not well defined. We aim to define prevalence and describe risk predictors for anal disease in a large population of solid organ transplant recipients. METHODS: Retrospective single-center cohort analysis included solid organ transplant recipients cared for between 2001 and 2022 (N = 15 362). The cohort of recipients who developed anal disease was compared with those who did not. Greedy propensity score matching was performed for organ-specific recipients, and time-to-event analysis for the development of anal disease was performed in those with genitourinary human papilloma virus (HPV) disease versus those without. RESULTS: Prevalence of anal disease was 0.6% (cancer 0.2%). The average years from transplant to the diagnosis of anal disease was 11.67. Anal disease was more common in women (68.5% versus 31.5%, P  < 0.001), patients who had other HPV-related genitourinary diseases (40.4% versus 0.6%, P  < 0.001), who were of younger age at transplant (39.62 versus 46.58, P  < 0.001), and had increased years from transplant (17.06 versus 12.57, P  < 0.001). In multivariate analysis, the odds of anal disease increased by 4% each year posttransplant. History of genitourinary HPV disease (odds ratio 69.63) and female sex (odds ratio 1.96) were the most significant risk predictors for anal disease. CONCLUSIONS: The prevalence of anal cancer among solid organ transplant recipients was equal to the general population (0.2%). Due to the low prevalence of overall disease, these data suggest that anal screenings in transplant recipients should be targeted to higher-risk subsets: female recipients farther out from transplant and patients with genitourinary HPV-related diseases.

Density of intertidal barnacles along their full elevational range of distribution conforms to the abundant-centre hypothesis.

The abundant-centre hypothesis (ACH) predicts that the density of a species should peak at its distribution centre and decrease similarly towards distribution margins. The ACH has been deduced from a theory that postulates that environmental conditions should be most favourable for a species at the centre of its distribution. This idealised density pattern, however, has been supported by limited field studies, as natural patterns are often more complex. It is thus of interest to examine under what conditions compliance with the ACH could be favoured. Such conditions could be smooth environmental gradients with limited habitat patchiness throughout the distribution range of a species. Thus, we tested the ACH by measuring the density of an intertidal barnacle (Semibalanus balanoides) across its full vertical distribution range (from low to high elevations) on a rocky shore with similar substrate properties across elevations. To do a reliable test, we surveyed eight elevation zones applying an equal sampling effort in each zone. Average barnacle density conformed to the ACH, as it peaked at the middle of the vertical distribution range of this species. The same underlying theory predicts a similar unimodal pattern for maximum body size, but this trait was decoupled from density, as maximum barnacle size increased from low to high elevations. Overall, although the ACH is not a universal predictive tool as once envisioned, it may predict some cases well, as shown by this study. Therefore, the ACH should not be discarded completely, and its domain of application should be further evaluated.

Retinoblastoma cells activate the AKT pathway and are vulnerable to the PI3K/mTOR inhibitor NVP-BEZ235.

Retinoblastoma is a pediatric cancer of the retina most often caused by inactivation of the retinoblastoma (RB1) tumor suppressor gene. We previously showed that Rb1 loss cooperates with either co-activating the phosphatidylinositol 3-kinase (PI3K)/AKT pathway, or co-deleting Pten, to initiate retinoblastoma tumors in mice. The objectives of this study were to determine if the AKT pathway is activated in human retinoblastomas and the extent that anti-PI3K therapy induces apoptosis in retinoblastoma cells, alone or in combination with the DNA damaging drugs carboplatin and topotecan. Serial sections from human retinoblastoma tissue microarrays containing 27 tumors were stained with antibodies specific to p-AKT, Ki-67, forkhead box O1 (p-FOXO1), and ribosomal protein S6 (p-S6) using immunohistochemistry and each tumor sample scored for intensity. Human retinoblastoma tumors displayed significant correlation between p-AKT intensity with highly proliferative tumors (p = 0.008) that were also highly positive for p-FOXO1 (p = 0.002). Treatment with BEZ235, a dual PI3K/mTOR inhibitor, reduced phosphorylation levels of the AKT targets p-FOXO and p-S6 and effectively induced apoptosis the Y79 and Weri-1 human retinoblastoma cell lines and in vivo in our retinoblastoma mouse model. Long-term treatment with BEZ235 in vivo using our retinoblastoma-bearing mice induced apoptosis but did not significantly extend the lifespan of the mice. We then co-administered BEZ235 with topotecan and carboplatin chemotherapeutics in vivo, which more effectively induced apoptosis of retinoblastoma, but not normal retinal cells than either treatment alone. Our study has increased the variety of potentially effective targeted treatments that can be considered for human retinoblastoma.

Loss of UHRF2 expression is associated with human neoplasia, promoter hypermethylation, decreased 5-hydroxymethylcytosine, and high proliferative activity.

Ubiquitin-like with PHD and ring finger domains 2 (UHRF2) binds to 5-hydroxymethylcytosine (5hmC), a DNA base involved in tissue development, but it is unknown how their distribution compares with each other in normal and malignant human tissues. We used IHC on human tumor specimens (160 from 19 tumor types) or normal tissue to determine the expression and distribution of UHRF2, Ki-67, and 5hmC. We also examined UHRF2 expression in cord blood progenitors and compared its expression to methylation status in 6 leukemia cell lines and 15 primary human leukemias. UHRF2 is highly expressed, paralleling that of 5hmC, in most non-neoplastic, differentiated tissue with low Ki-67 defined proliferative activity. UHRF2 is expressed in common lymphoid progenitors and mature lymphocytes but not common myeloid progenitors or monocytes. In contrast, UHRF2 immunostaining in human cancer tissues revealed widespread reduction or abnormal cytoplasmic localization which correlated with a higher Ki-67 and reduced 5hmC. UHRF2 expression is reduced in some leukemia cell lines, this correlates with promoter hypermethylation, and similar UHRF2 methylation profiles are seen in primary human leukemia samples. Thus, UHRF2 and 5hmC are widely present in differentiated human tissues, and UHRF2 protein is poorly expressed or mislocalized in diverse human cancers.