Notch induces transcription by stimulating release of paused RNA polymerase II.

Notch proteins undergo ligand-induced proteolysis to release a nuclear effector that influences a wide range of cellular processes by regulating transcription. Despite years of study, however, how Notch induces the transcription of its target genes remains unclear. Here, we comprehensively examine the response to human Notch1 across a time course of activation using high-resolution genomic assays of chromatin accessibility and nascent RNA production. Our data reveal that Notch induces target gene transcription primarily by releasing paused RNA polymerase II (RNAPII). Moreover, in contrast to prevailing models suggesting that Notch acts by promoting chromatin accessibility, we found that open chromatin was established at Notch-responsive regulatory elements prior to Notch signal induction through SWI/SNF-mediated remodeling. Together, these studies show that the nuclear response to Notch signaling is dictated by the pre-existing chromatin state and RNAPII distribution at the time of signal activation.

Discriminating North American Swine Influenza Viruses with a Portable, One-Step, Triplex Real-Time RT-PCR Assay, and Portable Sequencing.

Swine harbors a genetically diverse population of swine influenza A viruses (IAV-S), with demonstrated potential to transmit to the human population, causing outbreaks and pandemics. Here, we describe the development of a one-step, triplex real-time reverse transcription-polymerase chain reaction (rRT-PCR) assay that detects and distinguishes the majority of the antigenically distinct influenza A virus hemagglutinin (HA) clades currently circulating in North American swine, including the IAV-S H1 1A.1 (α), 1A.2 (ß), 1A.3 (γ), 1B.2.2 (δ1) and 1B.2.1 (δ2) clades, and the IAV-S H3 2010.1 clade. We performed an in-field test at an exhibition swine show using in-field viral concentration and RNA extraction methodologies and a portable real-time PCR instrument, and rapidly identified three distinct IAV-S clades circulating within the N.A. swine population. Portable sequencing is used to further confirm the results of the in-field test of the swine triplex assay. The IAV-S triplex rRT-PCR assay can be easily transported and used in-field to characterize circulating IAV-S clades in North America, allowing for surveillance and early detection of North American IAV-S with human outbreak and pandemic potential.

Fish couple forecasting with feedback control to chase and capture moving prey.

Predator-prey interactions are fundamental to ecological and evolutionary dynamics. Yet, predicting the outcome of such interactions-whether predators intercept prey or fail to do so-remains a challenge. An emerging hypothesis holds that interception trajectories of diverse predator species can be described by simple feedback control laws that map sensory inputs to motor outputs. This form of feedback control is widely used in engineered systems but suffers from degraded performance in the presence of processing delays such as those found in biological brains. We tested whether delay-uncompensated feedback control could explain predator pursuit manoeuvres using a novel experimental system to present hunting fish with virtual targets that manoeuvred in ways that push the limits of this type of control. We found that predator behaviour cannot be explained by delay-uncompensated feedback control, but is instead consistent with a pursuit algorithm that combines short-term forecasting of self-motion and prey motion with feedback control. This model predicts both predator interception trajectories and whether predators capture or fail to capture prey on a trial-by-trial basis. Our results demonstrate how animals can combine short-term forecasting with feedback control to generate robust flexible behaviours in the face of significant processing delays.

Bismuth-infused perivascular wrap facilitates delivery of mesenchymal stem cells and attenuation of neointimal hyperplasia in rat arteriovenous fistulas.

BACKGROUND: Mesenchymal stem cells (MSCs) have emerged as novel therapies for supporting arteriovenous fistula (AVF) maturation, and bioresorbable polymeric scaffolds have enabled sustained MSC delivery into maturing AVFs. However, the radiolucency of biopolymeric wraps prevents in vivo monitoring of their integrity and location, hindering long-term preclinical investigations. METHODS: We infused bismuth nanoparticles (BiNPs) into polycaprolactone (PCL) to fabricate an electrospun perivascular wrap capable of MSC delivery and conducive to longitudinal monitoring using conventional imaging. We tested the wraps' effects on the attenuation of markers of neointimal hyperplasia (i.e., endothelial dysfunction, hypoxia, and inflammation), the leading cause of AVF failure, in rats with induced chronic kidney disease (n = 3 per time point) for the following groups: control (no wrap), PCL wrap, PCL with MSCs, PCL-Bi (BiNP-infused wrap), and PCL-Bi with MSCs. RESULTS: Physicochemical characterization and in vitro biocompatibility tests revealed that BiNP infusion did not alter the wrap's non-cytotoxicity toward vascular cells, hemocompatibility, and capacity for MSC loading but facilitated long-term monitoring via micro-computed tomography. After 8 weeks, all treatment groups demonstrated significant improvement in wall-to-lumen ratio on ultrasonography (P < 0.001), neointima-to-lumen ratio on histomorphometry (P < 0.001), and attenuation of neointimal hypoxia on immunohistochemistry (P < 0.05). Compared to non-MSC wraps, MSC-loaded wraps not only attenuated endothelial dysfunction and neointimal inflammation but also reduced hypoxia and inflammation across all vascular layers. CONCLUSION: These results demonstrate that MSC delivery through a radiopaque polymeric wrap could enhance AVF patency outcomes through the inhibition of multiple pathways inducing AVF failure.

Stable isotopes reveal trophic ontogeny in Cisco (Coregonus artedi).

Cisco (Coregonus artedi) are a widespread, cold-water zooplanktivore native to North America. Although Cisco are generally referred to as an "obligate zooplanktivore," there is some evidence that the species exhibits considerable variability in trophic niche. Here, we assessed how Cisco body size relates to trophic position, that is, trophic ontogeny. We analysed 13C and 15N isotopes from Cisco ranging from 127 to 271 mm in body length (n = 66) from Trout Lake, Vilas County, Wisconsin, USA. 15N isotopes showed smaller Cisco had a trophic position of ~3, which steadily increased to ~3.5 for larger Cisco. Further, 13C isotope signatures showed Cisco transitioned to be more pelagically reliant (lower 13C signatures). Using gillnet catch data, we found that larger Cisco were using deeper habitats than smaller Cisco. Our results support that Cisco have significant variability in trophic niche even though they are traditionally thought of as an obligate planktivore. Overall, we emphasize that researchers should be cautious when generalizing Cisco trophic function, particularly when considering the broader food web.

Notch induces transcription by stimulating release of paused RNA Polymerase II.

Notch proteins undergo ligand-induced proteolysis to release a nuclear effector that influences a wide range of cellular processes by regulating transcription. Despite years of study, however, how Notch induces the transcription of its target genes remains unclear. Here, we comprehensively examined the response to human Notch1 across a time course of activation using high-resolution genomic assays of chromatin accessibility and nascent RNA production. Our data reveal that Notch induces target gene transcription primarily by releasing paused RNA polymerase II (RNAPII). Moreover, in contrast to prevailing models suggesting that Notch acts by promoting chromatin accessibility, we found that open chromatin was established at Notch-responsive regulatory elements prior to Notch signal induction, through SWI/SNF-mediated remodeling. Together, these studies show that the nuclear response to Notch signaling is dictated by the pre-existing chromatin state and RNAPII distribution at the time of signal activation.

Controlled Delivery of Rosuvastatin or Rapamycin through Electrospun Bismuth Nanoparticle-Infused Perivascular Wraps Promotes Arteriovenous Fistula Maturation.

In the context of arteriovenous fistula (AVF) failure, local delivery enables the release of higher concentrations of drugs that can suppress neointimal hyperplasia (NIH) while reducing systemic adverse effects. However, the radiolucency of polymeric delivery systems hinders long-term in vivo surveillance of safety and efficacy. We hypothesize that using a radiopaque perivascular wrap to deliver anti-NIH drugs could enhance AVF maturation. Through electrospinning, we fabricated multifunctional perivascular polycaprolactone (PCL) wraps loaded with bismuth nanoparticles (BiNPs) for enhanced radiologic visibility and drugs that can attenuate NIH─rosuvastatin (Rosu) and rapamycin (Rapa). The following groups were tested on the AVFs of a total of 24 Sprague-Dawley rats with induced chronic kidney disease: control (i.e., without wrap), PCL-Bi (i.e., wrap with BiNPs), PCL-Bi-Rosu, and PCL-Bi-Rapa. We found that BiNPs significantly improved the wraps' radiopacity without affecting biocompatibility. The drug release profiles of Rosu (hydrophilic drug) and Rapa (hydrophobic drug) differed significantly. Rosu demonstrated a burst release followed by gradual tapering over 8 weeks, while Rapa demonstrated a gradual release similar to that of the hydrophobic BiNPs. In vivo investigations revealed that both drug-loaded wraps can reduce vascular stenosis on ultrasonography and histomorphometry, as well as reduce [18F]Fluorodeoxyglucose uptake on positron emission tomography. Immunohistochemical studies revealed that PCL-Bi-Rosu primarily attenuated endothelial dysfunction and hypoxia in the neointimal layer, while PCL-Bi-Rapa modulated hypoxia, inflammation, and cellular proliferation across the whole outflow vein. In summary, the controlled delivery of drugs with different properties and mechanisms of action against NIH through a multifunctional, radiopaque perivascular wrap can improve imaging and histologic parameters of AVF maturation.

Integration of Electrospun Scaffolds and Biological Polymers for Enhancing the Delivery and Efficacy of Mesenchymal Stem/Stromal Cell Therapies.

Mesenchymal stem/stromal cells (MSCs) have emerged as a promising therapeutic approach for a variety of diseases due to their immunomodulatory and tissue regeneration capabilities. Despite their potential, the clinical application of MSC therapies is hindered by limited cell retention and engraftment at the target sites. Electrospun scaffolds, with their high surface area-to-volume ratio and tunable physicochemical properties, can be used as platforms for MSC delivery. However, synthetic polymers often lack the bioactive cues necessary for optimal cell-scaffold interactions. Integrating electrospun scaffolds and biological polymers, such as polysaccharides, proteins, and composites, combines the mechanical integrity of synthetic materials with the bioactivity of natural polymers and represents a strategic approach to enhance cell-scaffold interactions. The molecular interactions between MSCs and blended or functionalized scaffolds have been examined in recent studies, and it has been shown that integration can enhance MSC adhesion, proliferation, and paracrine secretion through the activation of multiple signaling pathways, such as FAK/Src, MAPK, PI3K/Akt, Wnt/ß-catenin, and YAP/TAZ. Preclinical studies on small animals also reveal that the integration of electrospun scaffolds and natural polymers represents a promising approach to enhancing the delivery and efficacy of MSCs in the context of regenerating bone, cartilage, muscle, cardiac, vascular, and nervous tissues. Future research should concentrate on identifying the distinct characteristics of the MSC niche, investigating the processes involved in MSC-scaffold interactions, and applying new technologies in stem cell treatment and biofabrication to enhance scaffold design. Research on large animal models and collaboration among materials scientists, engineers, and physicians are crucial to translating these advancements into clinical use.

Exploring a Masters of Business Administration's Impact on Surgical Subspecialists.

Objectives and Study Design: As healthcare evolves, more physicians are taking on administrative roles and pursuing additional graduate education, particularly obtaining a Master's in Business Administration (MBA.) To facilitate a better understanding of these practitioners, we conducted a comparative study of MD/MBA clinicians in multiple surgical fields. Methods: This study aims to compare clinicians with MD/MBAs across multiple surgical subspecialties. Reported metrics include demographics, MBA program structure, salary changes, and professional pursuits. Nine studies were obtained from the PubMed, Cochrane, and Embase databases. Four studies met the inclusion criteria and were analyzed. Results: The majority of MD/MBA degree holders in plastic surgery (95%), orthopedic surgery (89-96%), and ophthalmology (80%) are male. Ophthalmology (37%) demonstrates the highest number of subjects obtaining an MBA via a synchronous MD/MBA. Most clinicians return to clinical practice after degree completion and show high levels of non-clinical pursuits after receiving their MBAs. Conclusions: Though there appear to be differences across surgical subspecialties regarding how an MBA is applied, most maintain clinical duties. Of those that do not, the largest portion transition to administrative duties, consulting, entrepreneurial endeavors, or other professional opportunities. Despite the financial ambiguity of an MBA, physicians value the transformative experience it offers.

Antigenic Characterization of Circulating and Emerging SARS-CoV-2 Variants in the U.S. throughout the Delta to Omicron Waves.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evolved into numerous lineages with unique spike mutations and caused multiple epidemics domestically and globally. Although COVID-19 vaccines are available, new variants with the capacity for immune evasion continue to emerge. To understand and characterize the evolution of circulating SARS-CoV-2 variants in the U.S., the Centers for Disease Control and Prevention (CDC) initiated the National SARS-CoV-2 Strain Surveillance (NS3) program and has received thousands of SARS-CoV-2 clinical specimens from across the nation as part of a genotype to phenotype characterization process. Focus reduction neutralization with various antisera was used to antigenically characterize 143 SARS-CoV-2 Delta, Mu and Omicron subvariants from selected clinical specimens received between May 2021 and February 2023, representing a total of 59 unique spike protein sequences. BA.4/5 subvariants BU.1, BQ.1.1, CR.1.1, CQ.2 and BA.4/5 + D420N + K444T; BA.2.75 subvariants BM.4.1.1, BA.2.75.2, CV.1; and recombinant Omicron variants XBF, XBB.1, XBB.1.5 showed the greatest escape from neutralizing antibodies when analyzed against post third-dose original monovalent vaccinee sera. Post fourth-dose bivalent vaccinee sera provided better protection against those subvariants, but substantial reductions in neutralization titers were still observed, especially among BA.4/5 subvariants with both an N-terminal domain (NTD) deletion and receptor binding domain (RBD) substitutions K444M + N460K and recombinant Omicron variants. This analysis demonstrated a framework for long-term systematic genotype to antigenic characterization of circulating and emerging SARS-CoV-2 variants in the U.S., which is critical to assessing their potential impact on the effectiveness of current vaccines and antigen recommendations for future updates.

Graphitic Carbon Nitride as a Photocatalyst for Decarboxylative C(sp2)-C(sp3) Couplings via Nickel Catalysis.

The development of robust and reliable methods for the construction of C(sp2)-C(sp3) bonds is vital for accessing an increased array of structurally diverse scaffolds in drug discovery and development campaigns. While significant advances towards this goal have been achieved using metallaphotoredox chemistry, many of these methods utilise photocatalysts based on precious-metals due to their efficient redox processes and tuneable properties. However, due to the cost, scarcity, and toxicity of these metals, the search for suitable replacements should be a priority. Here, we show the use of commercially available heterogeneous semiconductor graphitic carbon nitride (gCN) as a photocatalyst, combined with nickel catalysis, for the cross-coupling between aryl halide and carboxylic acid coupling partners. gCN has been shown to engage in single-electron-transfer (SET) and energy-transfer (EnT) processes for the formation of C-X bonds, and in this manuscript we overcome previous limitations to furnish C-C over C-O bonds using carboxylic acids. A broad scope of both aryl halides and carboxylic acids is presented, and recycling of the photocatalyst demonstrated. The mechanism of the reaction is also investigated.

Predictors of Persistent Limp Following Proximal Femoral Varus Osteotomy for Perthes Disease.

INTRODUCTION: One of the most popular containment procedures for Legg-Calvé-Perthes disease (LCPD) is proximal femur varus osteotomy (PFO). While generally successful in achieving containment, PFO can cause limb length discrepancy, abductor weakness, and (of most concern for families) a persistent limp. While many studies have focused on radiographic outcomes following containment surgery, none have analyzed predictors of this persistent limp. The aim of this study was to determine clinical, radiographic, and surgical risk factors for persistent limp 2 years after PFO in children with LCPD. METHODS: A retrospective review of a prospectively collected multicenter database was conducted for patients aged 6 to 11 years at disease onset with unilateral early-stage LCPD (Waldenström I) who underwent PFO. Limp status (no, mild, and severe), age, BMI, and pain scores were obtained at initial presentation, 3-month, and 2-year postoperative visits. Preoperative and follow-up radiographs were used to measure traditional morphologic hip metrics including acetabular index (AI), lateral center-edge angle (LCEA), and femoral neck-shaft angle (NSA). Univariate analysis as well as multivariate logistic regression models were used to analyze factors associated with mild and severe limp at the 2-year visit. RESULTS: A total of 95 patients met the inclusion criteria, and of these 50 patients underwent concomitant greater trochanter apophysiodesis (GTA) at the time of PFO. At the 2-year visit, there were 38 patients (40%) with a mild or severe limp. Multivariate logistic regression revealed no significant radiographic factors associated with a persistent limp. However, lower 2-year BMI and undergoing GTA were associated with decreased rates of persistent limp regardless of age ( P <0.05). When stratifying by age of disease onset, apophysiodesis appeared to be protective against any severity of limp in patients aged 6 to 8 years old ( P = 0.03), but not in patients 8 years or older ( P = 0.49). CONCLUSIONS: Persistent limp following PFO is a frustrating problem that was seen in 40% of patients at 2 years. However, lower follow-up BMI and performing a greater trochanter apophysiodesis, particularly in patients younger than 8 years of age, correlated with a lower risk of postoperative limp.

Radical versus Local Surgical Excision for Early Rectal Cancer: A Systematic Review and Meta-Analysis.

Background: Radical excision (RE) for rectal cancer carries a higher risk of mortality and morbidity, while local excision (LE) could decrease these postoperative risks. However, the long-term benefit of LE is still debatable. Aim: To study the effectiveness of LE versus RE in T1 and T2 rectal cancer. Methods: A systematic review and meta-analysis was conducted using key databases like PubMed and ClinicalTrials.gov. Only cohort studies and randomized controlled trials were included. RevMan 5.4 tool was used for data analysis. Both clinical and statistical heterogeneity of the studies were assessed, and I2 >75% was considered as highly heterogeneous. The primary outcomes being measured were 5-year overall survival (OS) and 5-year disease free survival (DFS). A subgroup analysis of patients with T1-only was also conducted, without adjuvant chemo/radiotherapy. Results: A total of 18 studies were included for final meta-analysis. Four were RCTs, while the other 15 were retrospective cohort studies. One included study had data from both RCT and non-RCT study groups. Nine studies were multicentered or national studies while nine were unicentral.There was no difference in risk ratio (RR) between OS: RR 0.95, 95% Confidence Interval (CI) [0.91, 0.99] and DFS: RR 0.93, 95% CI [0.87, 1.01]. There were lower hazards ratios in OS: RR 1.41, 95% CI [1.14, 1.74] and DFS: RR 1.95, 95% CI [1.36, 2.78] with radical, as compared to LE. Lower recurrence rate was associated with RE. Random effect model was used due to clinical heterogeneity between studies (different surgical procedures, tumor staging, adjuvant chemo or radiotherapy). Conclusions: LE for early-stage rectal cancer has lower 5-year OS and DFS than RE, with higher local recurrence rate. However, LE is associated with lower early postoperative mortality, morbidity and length of stay as compared to RE.

Evaluating Chat Generative Pre-trained Transformer Responses to Common Pediatric In-toeing Questions.

OBJECTIVE: Chat generative pre-trained transformer (ChatGPT) has garnered attention in health care for its potential to reshape patient interactions. As patients increasingly rely on artificial intelligence platforms, concerns about information accuracy arise. In-toeing, a common lower extremity variation, often leads to pediatric orthopaedic referrals despite observation being the primary treatment. Our study aims to assess ChatGPT's responses to pediatric in-toeing questions, contributing to discussions on health care innovation and technology in patient education. METHODS: We compiled a list of 34 common in-toeing questions from the "Frequently Asked Questions" sections of 9 health care-affiliated websites, identifying 25 as the most encountered. On January 17, 2024, we queried ChatGPT 3.5 in separate sessions and recorded the responses. These 25 questions were posed again on January 21, 2024, to assess its reproducibility. Two pediatric orthopaedic surgeons evaluated responses using a scale of "excellent (no clarification)" to "unsatisfactory (substantial clarification)." Average ratings were used when evaluators' grades were within one level of each other. In discordant cases, the senior author provided a decisive rating. RESULTS: We found 46% of ChatGPT responses were "excellent" and 44% "satisfactory (minimal clarification)." In addition, 8% of cases were "satisfactory (moderate clarification)" and 2% were "unsatisfactory." Questions had appropriate readability, with an average Flesch-Kincaid Grade Level of 4.9 (±2.1). However, ChatGPT's responses were at a collegiate level, averaging 12.7 (±1.4). No significant differences in ratings were observed between question topics. Furthermore, ChatGPT exhibited moderate consistency after repeated queries, evidenced by a Spearman rho coefficient of 0.55 ( P = 0.005). The chatbot appropriately described in-toeing as normal or spontaneously resolving in 62% of responses and consistently recommended evaluation by a health care provider in 100%. CONCLUSION: The chatbot presented a serviceable, though not perfect, representation of the diagnosis and management of pediatric in-toeing while demonstrating a moderate level of reproducibility in its responses. ChatGPT's utility could be enhanced by improving readability and consistency and incorporating evidence-based guidelines. LEVEL OF EVIDENCE: Level IV-diagnostic.

A Chemically Inducible Muscle Ablation System for the Zebrafish.

An effective method for tissue-specific ablation in zebrafish is the nitroreductase (NTR)/metronidazole (MTZ) system. Expressing bacterial NTR in the presence of nitroimidazole compounds causes apoptotic cell death, which can be useful for understanding many biological processes. However, this requires tissue-specific expression of the NTR enzyme, and many tissues have yet to be targeted with transgenic lines that express NTR. We generated a transgenic zebrafish line expressing NTR in differentiated skeletal muscle. Treatment of embryos with MTZ caused muscle specific cell ablation. We demonstrate this line can be used to monitor muscle regeneration in whole embryos and in transplanted transgenic cells.

Cell cycle perturbation uncouples mitotic progression and invasive behavior in a post-mitotic cell.

The acquisition of the post-mitotic state is crucial for the execution of many terminally differentiated cell behaviors during organismal development. However, the mechanisms that maintain the post-mitotic state in this context remain poorly understood. To gain insight into these mechanisms, we used the genetically and visually accessible model of C. elegans anchor cell (AC) invasion into the vulval epithelium. The AC is a terminally differentiated uterine cell that normally exits the cell cycle and enters a post-mitotic state before initiating contact between the uterus and vulva through a cell invasion event. Here, we set out to identify the set of negative cell cycle regulators that maintain the AC in this post-mitotic, invasive state. Our findings revealed a critical role for CKI-1 (p21CIP1/p27KIP1) in redundantly maintaining the post-mitotic state of the AC, as loss of CKI-1 in combination with other negative cell cycle regulators-including CKI-2 (p21CIP1/p27KIP1), LIN-35 (pRb/p107/p130), FZR-1 (Cdh1/Hct1), and LIN-23 (ß-TrCP)-resulted in proliferating ACs. Remarkably, time-lapse imaging revealed that these ACs retain their ability to invade. Upon examination of a node in the gene regulatory network controlling AC invasion, we determined that proliferating, invasive ACs do so by maintaining aspects of pro-invasive gene expression. We therefore report that the requirement for a post-mitotic state for invasive cell behavior can be bypassed following direct cell cycle perturbation.

Live Imaging Transverse Sections of Zebrafish Embryo Explants.

Vertebrate embryogenesis is a highly dynamic process involving coordinated cell and tissue movements that generate the final embryonic body plan. Many of these movements are difficult to image at high resolution because they occur deep within the embryo along the midline, causing light scattering and requiring longer working distances. Here, we present an explant-based method to image transverse cross sections of living zebrafish embryos. This method allows for the capture of all cell movements at high-resolution throughout the embryonic trunk, including hard-to-image deep tissues. This technique offers an alternative to expensive or computationally difficult microscopy methods. Key features • Generates intact zebrafish explants with minimal tissue disturbance. • Allows for live imaging of deep tissues normally obscured by common confocal microscopy techniques. • Immobilizes tissues for extended periods required for time-lapse imaging. • Utilizes readily available reagents and tools, which can minimize the time and cost of the procedure.

Cell cycle perturbation uncouples mitotic progression and invasive behavior in a post-mitotic cell.

The acquisition of the post-mitotic state is crucial for the execution of many terminally differentiated cell behaviors during organismal development. However, the mechanisms that maintain the post-mitotic state in this context remain poorly understood. To gain insight into these mechanisms, we used the genetically and visually accessible model of C. elegans anchor cell (AC) invasion into the vulval epithelium. The AC is a terminally differentiated uterine cell that normally exits the cell cycle and enters a post-mitotic state, initiating contact between the uterus and vulva through a cell invasion event. Here, we set out to identify the set of negative cell cycle regulators that maintain the AC in this post-mitotic, invasive state. Our findings revealed a critical role for CKI-1 (p21CIP1/p27KIP1) in redundantly maintaining the post-mitotic state of the AC, as loss of CKI-1 in combination with other negative cell cycle regulators-including CKI-2 (p21CIP1/p27KIP1), LIN-35 (pRb/p107/p130), FZR-1 (Cdh1/Hct1), and LIN-23 (ß-TrCP)-resulted in proliferating ACs. Remarkably, time-lapse imaging revealed that these ACs retain their ability to invade. Upon examination of a node in the gene regulatory network controlling AC invasion, we determined that proliferating, invasive ACs do so by maintaining aspects of pro-invasive gene expression. We therefore report that the requirement for a post-mitotic state for invasive cell behavior can be bypassed following direct cell cycle perturbation.

In-field detection and characterization of B/Victoria lineage deletion variant viruses causing early influenza activity and an outbreak in Louisiana, 2019.

Background: In 2019, the Louisiana Department of Health reported an early influenza B/Victoria (B/VIC) virus outbreak. Method: As it was an atypically large outbreak, we deployed to Louisiana to investigate it using genomics and a triplex real-time RT-PCR assay to detect three antigenically distinct B/VIC lineage variant viruses. Results: The investigation indicated that B/VIC V1A.3 subclade, containing a three amino acid deletion in the hemagglutinin and known to be antigenically distinct to the B/Colorado/06/2017 vaccine virus, was the most prevalent circulating virus within the specimens evaluated (86/88 in real-time RT-PCR). Conclusion: This work underscores the value of portable platforms for rapid, onsite pathogen characterization.

Splicing modulators impair DNA damage response and induce killing of cohesin-mutant MDS and AML.

Splicing modulation is a promising treatment strategy pursued to date only in splicing factor-mutant cancers; however, its therapeutic potential is poorly understood outside of this context. Like splicing factors, genes encoding components of the cohesin complex are frequently mutated in cancer, including myelodysplastic syndromes (MDS) and secondary acute myeloid leukemia (AML), where they are associated with poor outcomes. Here, we showed that cohesin mutations are biomarkers of sensitivity to drugs targeting the splicing factor 3B subunit 1 (SF3B1) H3B-8800 and E-7107. We identified drug-induced alterations in splicing, and corresponding reduced gene expression, of a number of DNA repair genes, including BRCA1 and BRCA2, as the mechanism underlying this sensitivity in cell line models, primary patient samples and patient-derived xenograft (PDX) models of AML. We found that DNA damage repair genes are particularly sensitive to exon skipping induced by SF3B1 modulators due to their long length and large number of exons per transcript. Furthermore, we demonstrated that treatment of cohesin-mutant cells with SF3B1 modulators not only resulted in impaired DNA damage response and accumulation of DNA damage, but it sensitized cells to subsequent killing by poly(ADP-ribose) polymerase (PARP) inhibitors and chemotherapy and led to improved overall survival of PDX models of cohesin-mutant AML in vivo. Our findings expand the potential therapeutic benefits of SF3B1 splicing modulators to include cohesin-mutant MDS and AML.