Invasive Extravillous Trophoblasts Restrict Intracellular Growth and Spread of Listeria monocytogenes

Listeria monocytogenes is a facultative intracellular bacterial pathogen that can infect the placenta, a chimeric organ made of maternal and fetal cells. Extravillous trophoblasts (EVT) are specialized fetal cells that invade the uterine implantation site, where they come into direct contact with maternal cells. We have shown previously that EVT are the preferred site of initial placental infection. In this report, we infected primary human EVT with L. monocytogenes. EVT eliminated ∼80% of intracellular bacteria over 24-hours. Bacteria were unable to escape into the cytoplasm and remained confined to vacuolar compartments that became acidified and co-localized with LAMP1, consistent with bacterial degradation in lysosomes. In human placental organ cultures bacterial vacuolar escape rates differed between specific trophoblast subpopulations. The most invasive EVT—those that would be in direct contact with maternal cells in vivo—had lower escape rates than trophoblasts that were surrounded by fetal cells and tissues. Our results suggest that EVT present a bottleneck in the spread of L. monocytogenes from mother to fetus by inhibiting vacuolar escape, and thus intracellular bacterial growth. However, if L. monocytogenes is able to spread beyond EVT it can find a more hospitable environment. Our results elucidate a novel aspect of the maternal-fetal barrier

Microincisional vitrectomy for retinal detachment in I-125 brachytherapy-treated patients with posterior uveal malignant melanoma

Marcela Lonngi,1 Samuel K Houston,1 Timothy G Murray,1–3 Robert A Sisk,4 Christina L Decatur,1 Milena Cavalcante,1 Arnold M Markoe31Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, USA; 2Murray Ocular Oncology and Retina, Miami, FL, USA; 3Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, FL, USA; 4Department of Ophthalmology, Cincinnati Eye Institute, Cincinnati, OH, USAPurpose: To analyze functional and anatomical outcomes following 23/25+ gauge microincisional pars plana vitrectomy surgery (MIVS) in patients with radiation-related retinal detachment after successful 125-iodine (I-125) brachytherapy treatment for malignant uveal melanoma.Patients and methods: Retrospective case series of 102 consecutive eyes of 102 patients with history of uveal melanoma treated with I-125 brachytherapy that underwent MIVS at the Bascom Palmer Eye Institute. All cases were evaluated for surgical complications and local tumor control. Extended follow-up included Snellen’s best-corrected visual acuity, intraocular pressure evaluation, quantitative echography, indirect ophthalmoscopy, and fundus imaging with optical coherence tomography/wide-field photography.Results: All patients had radiation-related complications, including retinal detachment (102 eyes), vasculopathy (91 eyes), optic neuropathy (32 eyes), and/or vitreous hemorrhage (8 eyes). Sixty-seven patients had vitreoretinal traction. Average follow-up after MIVS was 19.5 months, and from plaque removal was 57.7 months. Interval from plaque to MIVS was 38.1 months. Initial visual acuity was 20/258, which improved to 20/101 at 1 month, 20/110 at 3 months, 20/116 at 6 months, and 20/113 at 12 months (P < 0.05). No eyes required enucleation. Melanoma-related mortality was 0.9% (1/102). There was no intra- or extraocular tumor dissemination, and no tumor recurrence.Conclusion: MIVS was effective in improving visual function and anatomy in patients with radiation-related retinal detachment. Tumors decreased in size and there was no evidence of recurrence or tumor dissemination. This combined procedure addresses the modifiable causes of visual loss in patients with previously treated malignant uveal melanoma and has the potential to enhance their visual function.Keywords: retinal detachment, vitrectomy, melanoma, radiation-related complication

Epigenetic reprogramming and aberrant expression of PRAME are associated with increased metastatic risk in Class 1 and Class 2 uveal melanomas.

BACKGROUND: We previously identified PRAME as a biomarker for metastatic risk in Class 1 uveal melanomas. In this study, we sought to define a threshold value for positive PRAME expression (PRAME+) in a large dataset, identify factors associated with PRAME expression, evaluate the prognostic value of PRAME in Class 2 uveal melanomas, and determine whether PRAME expression is associated with aberrant hypomethylation of the PRAME promoter. RESULTS: Among 678 samples analyzed by qPCR, 498 (73.5%) were PRAME- and 180 (26.5%) were PRAME+. Class 1 tumors were more likely to be PRAME-, whereas Class 2 tumors were more likely to be PRAME+ (P < 0.0001). PRAME expression was associated with shorter time to metastasis and melanoma specific mortality in Class 2 tumors (P = 0.01 and P = 0.02, respectively). In Class 1 tumors, PRAME expression was directly associated with SF3B1 mutations (P < 0.0001) and inversely associated with EIF1AX mutations (P = 0.004). PRAME expression was strongly associated with hypomethylation at 12 CpG sites near the PRAME promoter. MATERIALS AND METHODS: Analyses included PRAME mRNA expression, Class 1 versus Class 2 status, chromosomal copy number, mutation status of BAP1, EIF1AX, GNA11, GNAQ and SF3B1, and genomic DNA methylation status. Analyses were performed on 555 de-identified samples from Castle Biosciences, 123 samples from our center, and 80 samples from the TCGA. CONCLUSIONS: PRAME is aberrantly hypomethylated and activated in Class 1 and Class 2 uveal melanomas and is associated with increased metastatic risk in both classes. Since PRAME has been successfully targeted for immunotherapy, it may prove to be a companion prognostic biomarker

Immature small ribosomal subunits can engage in translation initiation in Saccharomyces cerevisiae

It is generally assumed that, in Saccharomyces cerevisiae, immature 40S ribosomal subunits are not competent for translation initiation. Here, we show by different approaches that, in wild-type conditions, a portion of pre-40S particles (pre-SSU) associate with translating ribosomal complexes. When cytoplasmic 20S pre-rRNA processing is impaired, as in Rio1p- or Nob1p-depleted cells, a large part of pre-SSUs is associated with translating ribosomes complexes. Loading of pre-40S particles onto mRNAs presumably uses the canonical pathway as translation-initiation factors interact with 20S pre-rRNA. However, translation initiation is not required for 40S ribosomal subunit maturation. We also provide evidence suggesting that cytoplasmic 20S pre-rRNAs that associate with translating complexes are turned over by the no go decay (NGD) pathway, a process known to degrade mRNAs on which ribosomes are stalled. We propose that the cytoplasmic fate of 20S pre-rRNA is determined by the balance between pre-SSU processing kinetics and sensing of ribosome-like particles loaded onto mRNAs by the NGD machinery, which acts as an ultimate ribosome quality check point