poly(UG)-tailed RNAs in genome protection and epigenetic inheritance.

Mobile genetic elements threaten genome integrity in all organisms. RDE-3 (also known as MUT-2) is a ribonucleotidyltransferase that is required for transposon silencing and RNA interference in Caenorhabditis elegans1-4. When tethered to RNAs in heterologous expression systems, RDE-3 can add long stretches of alternating non-templated uridine (U) and guanosine (G) ribonucleotides to the 3' termini of these RNAs (designated poly(UG) or pUG tails)5. Here we show that, in its natural context in C. elegans, RDE-3 adds pUG tails to targets of RNA interference, as well as to transposon RNAs. RNA fragments attached to pUG tails with more than 16 perfectly alternating 3' U and G nucleotides become gene-silencing agents. pUG tails promote gene silencing by recruiting RNA-dependent RNA polymerases, which use pUG-tailed RNAs (pUG RNAs) as templates to synthesize small interfering RNAs (siRNAs). Our results show that cycles of pUG RNA-templated siRNA synthesis and siRNA-directed pUG RNA biogenesis underlie double-stranded-RNA-directed transgenerational epigenetic inheritance in the C. elegans germline. We speculate that this pUG RNA-siRNA silencing loop enables parents to inoculate progeny against the expression of unwanted or parasitic genetic elements.

Intra- and interlaboratory reproducibility evaluation toward international validation status of the AmpFire assay.

To meet the screening goal of WHO's 90-70-90 strategy aimed at eliminating cervical cancer (CC) by 2030, clinical validation of human papillomavirus (HPV) assays is essential to provide accurate and valid results through fulfilling three criteria of the international validation guidelines (IVGs). Previously, the clinical accuracy of the AmpFire® HPV Screening 16/18/HR assay (AmpFire assay) was reported but reproducibility data are lacking. Here, we aim to evaluate the intra- and inter-laboratory reproducibility of the AmpFire assay. The reproducibility of the isothermal AmpFire assay was assessed using 556 cervical cell samples collected from women attending CC screening and biobanked in a Belgian HPV national reference center. This assay detects HPV16, HPV18, and 12 other high-risk HPV (hrHPV) types (31/33/35/39/45/51/52/56/58/59/66/68) in aggregate. Lower 95% confidence interval bound around the assay's reproducibility should exceed 87%, with κ ≥ 0.50. Additionally, a literature review of the assay's clinical performance was performed. The AmpFire assay showed an excellent intralaboratory (96.4%, 95% CI:94.5-97.8%, κ = 0.920) and interlaboratory (95.3%, 95% CI:93.2-96.9%, κ = 0.897) reproducibility. One study demonstrated noninferior sensitivity of a prototype AmpFire assay targeting 15 hrHPV types (including HPV53) to detect CIN2+. However, clinical specificity became similar to the comparator after removing HPV53 from analyses. The low-cost and easy-to-use AmpFire assay presents excellent reproducibility and-after removing HPV53 from the targeted types-fulfills also clinical accuracy requirements. Inclusion of HPV53, which is not recognized as carcinogenic, comprises clinical specificity of screening assays.

Pediatric primary lymphoma of bone in epiphysis case report.

Primary lymphoma of the bone (PLB) is a rare entity, with a majority of pediatric cases presenting in the metaphysis of long bones. There have been only seven reported cases to date of pediatric lymphoma of the bone arising from the epiphysis, of which only two have been described in the proximal tibia. We report a pediatric case of PLB in the tibial epiphysis which presented initially with knee pain. Imaging was performed with X-ray, MRI, CT, and PET-CT with bone biopsies revealing diffuse large B-cell lymphoma. This patient also showed a second, synchronous lesion in the left iliac bone, which was also biopsy proven to diffuse large B-cell lymphoma. Lymphoma in the epiphysis for children is rare and often confused with infectious etiologies or other types of tumors. Misdiagnosis may result in inappropriate treatment and possible progression of the disease, thus making early identification important to initiate therapy.

Intra- and interlaboratory reproducibility of the RIATOL qPCR HPV genotyping assay.

The implementation of cervical screening based on human papillomavirus (HPV) continues to progress rapidly across countries. Evidence has shown that assays detecting high-risk human papillomavirus (hrHPV) deoxyribonucleic acid (DNA) are more effective than cytology-based screening. Validation of new hrHPV DNA assays requires both noninferior clinical accuracy compared to a standard comparator for cervical precancer and good reproducibility. This study builds upon previous diagnostic accuracy assessments of the RIATOL HPV genotyping qPCR assay and aims to evaluate the international validation criteria for reproducibility. The intra- and interreproducibility of the RIATOL-qPCR assay were assessed using 550 remnant cervical cell material from the cytology archive of the National Reference Center for HPV in Belgium. Specimens were collected in the context of cervical cancer screening and tested in two different laboratories. The international reproducibility criteria include the lower bound of 95% confidence interval of the intra- and interlaboratory agreement regarding the detection of hrHPV DNA exceeding 87% with kappa ≥0.50. The RIATOL-qPCR assay demonstrated excellent intralaboratory reproducibility, achieving an overall agreement of 98.2 (95% CI 96.6-99.1%) and a kappa of 0.96. Interlaboratory testing showed an overall agreement of 98.5 (95% CI 97.1-99.4%) with a kappa of 0.97. The RIATOL-qPCR assay fulfills the third criterion for HPV test reproducibility requirement for use in cervical cancer screening.

Evaluation of the clinical performance of OncoPredict HPV® SCR assay within the VALGENT-2 framework.

Human papillomavirus (HPV) assays used in cervical cancer screening should be clinically validated according to international criteria. OncoPredict HPV® Screening (SCR) is a partial genotyping multiplex real-time PCR assay targeting E6/E7 genes of 13 high-risk (hr) HPVs. OncoPredict HPV® SCR (index assay) identifies HPV-16 and HPV-18 separately, 11 other hrHPV in aggregate and includes quality controls for sample adequacy, DNA extraction efficiency and PCR inhibition. 1300 VALGENT-2 study samples (from women aged 20-60 attending the Scottish cervical cancer screening program) were tested with the index assay and the GP5+/6+ PCR enzyme immunoassay (standard comparator assay). Non-inferior accuracy detecting cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) of the index versus comparator was verified. Intra- and interlaboratory reproducibility of the index was evaluated by overall concordance and Cohen's kappa, using a sub-population (n = 526). Relative sensitivity and specificity for CIN2+ of the index versus comparator were 1.01 (95% confidence interval [CI]: 0.99-1.03) and 1.02 (95% CI: 1.0-1.04), respectively. Noninferiority p values were all ≤0.05, except for CIN3+ in patients ≥30 years. Excellent intra- and interlaboratory reproducibility was shown with concordance >98% and kappas >0.95. OncoPredict HPV® SCR fulfills the three international validation criteria for hrHPV DNA tests in cervical cancer screening.

Urinary Tract Infection Epidemiology in NICUs in the United States.

OBJECTIVE: Our objective was to characterize the incidence, associated clinical factors, timing of infection, microbiology, and incidence of concordant blood culture of urinary tract infections (UTIs) in very low birth weight (VLBW <1,500g) infants. STUDY DESIGN: Multicenter observational cohort study of VLBW infants with gestational age (GA) ≤32 weeks, still hospitalized on postnatal day 7, and discharged 2010 to 2018 from Pediatrix Medical Group neonatal intensive care units. Demographic and clinical characteristics of infants with and without UTI were compared. Multivariable logistic regression evaluated adjusted odds of UTI diagnosis. RESULTS: Of 86,492 included infants, 5,988 (7%) had a UTI. The most common pathogen was Enterococcus spp. (20%), followed by Escherichia coli (19%) and Klebsiella spp. (18%). Candida spp. (6%) was the most common nonbacterial pathogen. Concordant-positive blood culture was present in 8% of infants with UTI diagnoses. UTI was associated with lower GA, male sex, vaginal delivery, prenatal steroid exposure, and longer duration of hospitalization. CONCLUSION: UTI is a common cause of infection in VLBW infants, especially among the smallest, most premature, male infants, and those with a longer duration of hospitalization. Neonatal clinicians should consider obtaining urine culture in the setting of late-onset sepsis evaluations in VLBW infants. KEY POINTS: · UTI is a common cause of LOS in VLBW infants.. · The most common pathogens are Enterococcus spp. and E. coli.. · UTI risk varies among different VLBW infant populations.. · Next steps should include evaluation of preventative measures..

COVID-19 vaccine effectiveness against symptomatic infection and hospitalisation in Belgium, July 2021 to May 2022.

BackgroundThe Belgian COVID-19 vaccination campaign aimed to reduce disease spread and severity.AimWe estimated SARS-CoV-2 variant-specific vaccine effectiveness against symptomatic infection (VEi) and hospitalisation (VEh), given time since vaccination and prior infection.MethodsNationwide healthcare records from July 2021 to May 2022 on testing and vaccination were combined with a clinical hospital survey. We used a test-negative design and proportional hazard regression to estimate VEi and VEh, controlling for prior infection, time since vaccination, age, sex, residence and calendar week of sampling.ResultsWe included 1,932,546 symptomatic individuals, of whom 734,115 tested positive. VEi against Delta waned from an initial estimate of 80% (95% confidence interval (CI): 80-81) to 55% (95% CI: 54-55) 100-150 days after the primary vaccination course. Booster vaccination increased initial VEi to 85% (95% CI: 84-85). Against Omicron, an initial VEi of 33% (95% CI: 30-36) waned to 17% (95% CI: 15-18), while booster vaccination increased VEi to 50% (95% CI: 49-50), which waned to 20% (95% CI: 19-21) 100-150 days after vaccination. Initial VEh for booster vaccination decreased from 96% (95% CI: 95-96) against Delta to 87% (95% CI: 86-89) against Omicron. VEh against Omicron waned to 73% (95% CI: 71-75) 100-150 days after booster vaccination. While recent prior infections conferred higher protection, infections occurring before 2021 remained associated with significant risk reduction against symptomatic infection. Vaccination and prior infection outperformed vaccination or prior infection only.ConclusionWe report waning and a significant decrease in VEi and VEh from Delta to Omicron-dominant periods. Booster vaccination and prior infection attenuated these effects.

Clinical features and MRI characteristics of retinal detachment in dogs and cats.

The aim of this retrospective observational study was to characterize the MRI appearance of retinal detachment (RD) in a sample of dogs and cats. Study inclusion was based on the following medical record criteria: (a) had a diagnosis of RD in at least one eye by either funduscopic examination or ocular ultrasound and had an MRI evaluation including the eyes, or (b) had a diagnosis of RD documented in an MRI report for at least one eye and also had a clinical eye examination. Eighteen patients (12 dogs, 6 cats) and 35 eyes met the inclusion criteria, although four eyes that were clinically examined could not be visualized funduscopically and did not have ocular ultrasound performed (criterion 2). The MRI and clinical diagnosis (via either funduscopy or ultrasound) of RD/no RD was concordant in 27 of 31 eyes (87%). Qualitatively, RD appeared as a variable intensity curvilinear structure located internal and adjacent to the sclera on all sequences and was best delineated on T2W sequences. RDs inconsistently contrast enhanced and, although there was no statistical difference, subjectively appeared more clearly delineated on dorsal and parasagittal images. In conclusion, findings from the current study support using MRI as an ancillary diagnostic test for confirmation or further characterization of RD in dogs and cats.

Regulatory logic driving stable levels of defective proventriculus expression during terminal photoreceptor specification in flies.

How differential levels of gene expression are controlled in post-mitotic neurons is poorly understood. In the Drosophila retina, expression of the transcription factor Defective Proventriculus (Dve) at distinct cell type-specific levels is required for terminal differentiation of color- and motion-detecting photoreceptors. Here, we find that the activities of two cis-regulatory enhancers are coordinated to drive dve expression in the fly eye. Three transcription factors act on these enhancers to determine cell-type specificity. Negative autoregulation by Dve maintains expression from each enhancer at distinct homeostatic levels. One enhancer acts as an inducible backup ('dark' shadow enhancer) that is normally repressed but becomes active in the absence of the other enhancer. Thus, two enhancers integrate combinatorial transcription factor input, feedback and redundancy to generate cell type-specific levels of dve expression and stable photoreceptor fate. This regulatory logic may represent a general paradigm for how precise levels of gene expression are established and maintained in post-mitotic neurons.

The insulator protein BEAF-32 is required for Hippo pathway activity in the terminal differentiation of neuronal subtypes.

The Hippo pathway is crucial for not only normal growth and apoptosis but also cell fate specification during development. What controls Hippo pathway activity during cell fate specification is incompletely understood. In this article, we identify the insulator protein BEAF-32 as a regulator of Hippo pathway activity in Drosophila photoreceptor differentiation. Though morphologically uniform, the fly eye is composed of two subtypes of R8 photoreceptor neurons defined by expression of light-detecting Rhodopsin proteins. In one R8 subtype, active Hippo signaling induces Rhodopsin 6 (Rh6) and represses Rhodopsin 5 (Rh5), whereas in the other subtype, inactive Hippo signaling induces Rh5 and represses Rh6. The activity state of the Hippo pathway in R8 cells is determined by the expression of warts, a core pathway kinase, which interacts with the growth regulator melted in a double-negative feedback loop. We show that BEAF-32 is required for expression of warts and repression of melted Furthermore, BEAF-32 plays a second role downstream of Warts to induce Rh6 and prevent Rh5 fate. BEAF-32 is dispensable for Warts feedback, indicating that BEAF-32 differentially regulates warts and Rhodopsins. Loss of BEAF-32 does not noticeably impair the functions of the Hippo pathway in eye growth regulation. Our study identifies a context-specific regulator of Hippo pathway activity in post-mitotic neuronal fate, and reveals a developmentally specific role for a broadly expressed insulator protein.

Long-term multilineage engraftment of autologous genome-edited hematopoietic stem cells in nonhuman primates.

Genome editing in hematopoietic stem and progenitor cells (HSPCs) is a promising novel technology for the treatment of many human diseases. Here, we evaluated whether the disruption of the C-C chemokine receptor 5 (CCR5) locus in pigtailed macaque HSPCs by zinc finger nucleases (ZFNs) was feasible. We show that macaque-specific CCR5 ZFNs efficiently induce CCR5 disruption at levels of up to 64% ex vivo, 40% in vivo early posttransplant, and 3% to 5% in long-term repopulating cells over 6 months following HSPC transplant. These genome-edited HSPCs support multilineage engraftment and generate progeny capable of trafficking to secondary tissues including the gut. Using deep sequencing technology, we show that these ZFNs are highly specific for the CCR5 locus in primary cells. Further, we have adapted our clonal tracking methodology to follow individual CCR5 mutant cells over time in vivo, reinforcing that CCR5 gene-edited HSPCs are capable of long-term engraftment. Together, these data demonstrate that genome-edited HSPCs engraft, and contribute to multilineage repopulation after autologous transplantation in a clinically relevant large animal model, an important step toward the development of stem cell-based genome-editing therapies for HIV and potentially other diseases as well.

Mapping the molecular determinants of BRAF oncogene dependence in human lung cancer.

Oncogenic mutations in the BRAF kinase occur in 6-8% of nonsmall cell lung cancers (NSCLCs), accounting for more than 90,000 deaths annually worldwide. The biological and clinical relevance of these BRAF mutations in NSCLC is incompletely understood. Here we demonstrate that human NSCLC cells with BRAF(V600E), but not other BRAF mutations, initially are sensitive to BRAF-inhibitor treatment. However, these BRAF(V600E) NSCLC cells rapidly acquire resistance to BRAF inhibition through at least one of two discrete molecular mechanisms: (i) loss of full-length BRAF(V600E) coupled with expression of an aberrant form of BRAF(V600E) that retains RAF pathway dependence or (ii) constitutive autocrine EGF receptor (EGFR) signaling driven by c-Jun-mediated EGFR ligand expression. BRAF(V600E) cells with EGFR-driven resistance are characterized by hyperphosphorylated protein kinase AKT, a biomarker we validated in BRAF inhibitor-resistant NSCLC clinical specimens. These data reveal the multifaceted molecular mechanisms by which NSCLCs establish and regulate BRAF oncogene dependence, provide insights into BRAF-EGFR signaling crosstalk, and uncover mechanism-based strategies to optimize clinical responses to BRAF oncogene inhibition.

Acute knockdown of AMPA receptors reveals a trans-synaptic signal for presynaptic maturation.

Newly formed glutamatergic synapses often lack postsynaptic AMPA-type glutamate receptors (AMPARs). Aside from 'unsilencing' the postsynaptic site, however, the significance of postsynaptic AMPAR insertion during synapse maturation remains unclear. To investigate the role of AMPAR in synapse maturation, we used RNA interference (RNAi) to knockdown AMPARs in cultured hippocampal neurons. Surprisingly, loss of postsynaptic AMPARs increased the occurrence of presynaptically inactive synapses without changing the release probability of the remaining active synapses. Additionally, heterologous synapses formed between axons and AMPAR-expressing HEK cells develop significantly fewer inactive presynaptic terminals. The extracellular domain of the AMPAR subunit GluA2 was sufficient to reproduce this effect at heterologous synapses. Indeed, the retrograde signalling by AMPARs is independent of their channel function as RNAi-resistant AMPARs restore synaptic transmission in neurons lacking AMPARs despite chronic receptor antagonist treatment. Our findings suggest that postsynaptic AMPARs perform an organizational function at synapses that exceeds their standard role as ionotropic receptors by conveying a retrograde trans-synaptic signal that increases the transmission efficacy at a synapse.

Targeted gene addition to a predetermined site in the human genome using a ZFN-based nicking enzyme.

Zinc-finger nucleases (ZFNs) drive highly efficient genome editing by generating a site-specific DNA double-strand break (DSB) at a predetermined site in the genome. Subsequent repair of this break via the nonhomologous end-joining (NHEJ) or homology-directed repair (HDR) pathways results in targeted gene disruption or gene addition, respectively. Here, we report that ZFNs can be engineered to induce a site-specific DNA single-strand break (SSB) or nick. Using the CCR5-specific ZFNs as a model system, we show that introduction of a nick at this target site stimulates gene addition using a homologous donor template but fails to induce significant levels of the small insertions and deletions (indels) characteristic of repair via NHEJ. Gene addition by these CCR5-targeted zinc finger nickases (ZFNickases) occurs in both transformed and primary human cells at efficiencies of up to ∼1%-8%. Interestingly, ZFNickases targeting the AAVS1 "safe harbor" locus revealed similar in vitro nicking activity, a marked reduction of indels characteristic of NHEJ, but stimulated far lower levels of gene addition-suggesting that other, yet to be identified mediators of nick-induced gene targeting exist. Introduction of site-specific nicks at distinct endogenous loci provide an important tool for the study of DNA repair. Moreover, the potential for a SSB to direct repair pathway choice (i.e., HDR but not NHEJ) may prove advantageous for certain therapeutic applications such as the targeted correction of human disease-causing mutations.

DNA copy number concentration measured by digital and droplet digital quantitative PCR using certified reference materials.

The value assignment for properties of six certified reference materials (ERM-AD623a-f), each containing a plasmid DNA solution ranging from 1 million to 10 copies per µL, by using digital PCR (dPCR) with the BioMark™ HD System (Fluidigm) has been verified by applying droplet digital PCR (ddPCR) using the QX100 system (Bio-Rad). One of the critical factors in the measurement of copy number concentrations by digital PCR is the partition volume. Therefore, we determined the average droplet volume by optical microscopy, revealing an average droplet volume that is 8 % smaller than the droplet volume used as the defined parameter in the QuantaSoft software version 1.3.2.0 (Bio-Rad) to calculate the copy number concentration. This observation explains why copy number concentrations estimated with ddPCR and using an average droplet volume predefined in the QuantaSoft software were systematically lower than those measured by dPCR, creating a significant bias between the values obtained by these two techniques. The difference was not significant anymore when the measured droplet volume of 0.834 nL was used to estimate copy number concentrations. A new version of QuantaSoft software (version 1.6.6.0320), which has since been released with Bio-Rad's new QX200 systems and QX100 upgrades, uses a droplet volume of 0.85 nL as a defined parameter to calculate copy number concentration.

Commentary on mentorship in residency with novel program: Mentorship Expanded Networking and Teaching to Integrate and Enhance Residency (MEN-TIER).

BACKGROUND: Mentorship is the foundation for training and career development. However, only about half of interventional radiology (IR) residency programs in the United States have a formal mentorship program at their institution. A new tiered mentorship program was introduced at our institution. METHODS: A structured mentorship program was created at our institution in 2020 for IR residents to pair 1-2 faculty advisors with a group of residents, one from each PGY class, based on personal interests and career paths. A quality improvement survey with Likert scale format (1-5) was sent to IR residents and faculty members. RESULTS: Responses were recorded from 11 IR residents in addition to all 6 IR faculty mentors. IR respondents reported satisfaction with feeling more assimilated in the department and all would recommend the current mentorship model to other institutions. Most respondents agreed the program made them comfortable conducting effective mentorship relationships as an attending and that the tiered structured of being mentee and mentor simultaneously was beneficial. Both IR residents and faculty agreed that the program helped prevent burnout. CONCLUSIONS: The tiered mentorship model has had a positive impact on the IR program by providing structured mentoring and longitudinal relationships. The most notable benefits for IR residents is the early integration into the program, sustained mentorships relationships, and the prevention of burnout. Similar models can help other programs establish structured faculty and peer mentorship for residents early in training.

Innovations in the Treatment of Spinal Cerebrospinal Fluid Leaks.

Spontaneous spinal cerebrospinal fluid (CSF) leaks are uncommon but can be neurologically debilitating. When initial treatments fail, definitive repair or closure of the leak is indicated. Depending upon the type of leak present, innovative strategies for their treatment have been developed. Among them are open surgical techniques using a transdural approach for the closure of ventral CSF leaks, minimally invasive tubular techniques for the reduction and repair of lateral meningeal diverticula, and endovascular embolization of CSF-venous fistulas. Illustrative cases demonstrating the indications for and implementation of these techniques are provided.

Cranial and Spinal Cerebrospinal Fluid Leaks: Foundations of Identification and Management.

Cerebrospinal fluid (CSF) leaks may occur at the skull base or along the spinal column and can cause a variety of debilitating neurological symptoms for patients. Recognizing the potential presence of a CSF leak and then identifying its source are necessary for accurate diagnosis and definitive treatment. A standardized workflow can be followed for successful leak localization, which often requires several diagnostic studies, and for definitive leak treatment, which can range from minimally invasive, needle-based approaches to a variety of surgical corrections. This review paper provides an overview of epidemiology, pathophysiology, and diagnostic workup for CSF leaks and introduces available treatment options. An illustrative case of a skull base CSF leak demonstrating diagnosis and surgical correction is provided.