Rbfox Proteins Regulate Splicing as Part of a Large Multiprotein Complex LASR.

Rbfox proteins control alternative splicing and posttranscriptional regulation in mammalian brain and are implicated in neurological disease. These proteins recognize the RNA sequence (U)GCAUG, but their structures and diverse roles imply a variety of protein-protein interactions. We find that nuclear Rbfox proteins are bound within a large assembly of splicing regulators (LASR), a multimeric complex containing the proteins hnRNP M, hnRNP H, hnRNP C, Matrin3, NF110/NFAR-2, NF45, and DDX5, all approximately equimolar to Rbfox. We show that splicing repression mediated by hnRNP M is stimulated by Rbfox. Virtually all the intron-bound Rbfox is associated with LASR, and hnRNP M motifs are enriched adjacent to Rbfox crosslinking sites in vivo. These findings demonstrate that Rbfox proteins bind RNA with a defined set of cofactors and affect a broader set of exons than previously recognized. The function of this multimeric LASR complex has implications for deciphering the regulatory codes controlling splicing networks.

Activity-dependent transport of the transcriptional coactivator CRTC1 from synapse to nucleus.

Long-lasting changes in synaptic efficacy, such as those underlying long-term memory, require transcription. Activity-dependent transport of synaptically localized transcriptional regulators provides a direct means of coupling synaptic stimulation with changes in transcription. The CREB-regulated transcriptional coactivator (CRTC1), which is required for long-term hippocampal plasticity, binds CREB to potently promote transcription. We show that CRTC1 localizes to synapses in silenced hippocampal neurons but translocates to the nucleus in response to localized synaptic stimulation. Regulated nuclear translocation occurs only in excitatory neurons and requires calcium influx and calcineurin activation. CRTC1 is controlled in a dual fashion with activity regulating CRTC1 nuclear translocation and cAMP modulating its persistence in the nucleus. Neuronal activity triggers a complex change in CRTC1 phosphorylation, suggesting that CRTC1 may link specific types of stimuli to specific changes in gene expression. Together, our results indicate that synapse-to-nuclear transport of CRTC1 dynamically informs the nucleus about synaptic activity.

Anchoring local translation in neurons.

In probing how protein synthesis in neurons is coupled to extracellular stimuli, Tcherkezian et al. (2010) discover that the receptor protein DCC anchors components of the translation machinery at the plasma membrane. Binding of DCC to its ligand, netrin, triggers the release of these components to initiate spatially restricted protein synthesis.

mRNA localization: gene expression in the spatial dimension.

The localization of mRNAs to subcellular compartments provides a mechanism for regulating gene expression with exquisite temporal and spatial control. Recent studies suggest that a large fraction of mRNAs localize to distinct cytoplasmic domains. In this Review, we focus on cis-acting RNA localization elements, RNA-binding proteins, and the assembly of mRNAs into granules that are transported by molecular motors along cytoskeletal elements to their final destination in the cell.

Disparities in arthroplasty utilization for rotator cuff tear arthropathy.

BACKGROUND: Rotator cuff tear arthropathy (CTA) carries a significant symptomatic burden for patients. Reverse shoulder arthroplasty (RSA) is an effective treatment intervention for CTA. Disparities in musculoskeletal medicine are well documented; however, there is a paucity of literature on how social determinants of health affect utilization rates. The purpose of this study is to determine how social determinants of health affect the utilization rates of RSA. METHODS: A single-center retrospective review was conducted for adult patients diagnosed with CTA between 2015 and 2020. Patients were divided by those who underwent RSA and those who were offered RSA but did not undergo surgery. Each patient's zip code was used to determine the most specific median household income in the US Census Bureau database and compared to the multistate metropolitan statistical area median income. Income levels were defined by the US Department of Housing and Urban Development's (HUD's) 2022 Income Limits Documentation System and the Federal Reserve's (FED's) Community Reinvestment Act. Because of numeric restrictions, patients were grouped into racial cohorts of Black, White, and all other races. RESULTS: Patients of other races had significantly lower odds of continuing to surgery compared with White patients in models controlled for median household income (odds ratio [OR] 0.38, 95% confidence interval [CI] 0.18-0.81, P = .01), HUD's 3 income levels (OR 0.36, 95% CI 0.18-0.74, P = .01), and FED's income levels (OR 0.37, 95% CI 0.17-0.79, P = .01). There was no significantly different odds of going on to surgery between FED income levels and median household income levels, but when compared with those with low HUD income, those below median had significantly lower odds of going on to surgery (OR 0.43, 95% CI 0.23-0.80, P = .01). CONCLUSION: Although contradictory to reported health care utilization for Black patients, our study supports reported disparities in utilization for other ethnic minorities. These findings may suggest that improvements in utilization efforts targeted Black-identifying patients but not necessarily other ethnic minorities. The findings of this study can help providers understand how social determinants of health play a role in the utilization of care for CTA and direct mitigation efforts to reduce disparities in access to adequate orthopedic care.

Outcomes of hip fracture surgery during the COVID-19 pandemic.

PURPOSE: To investigate if changes to hospital operational models during the COVID-19 pandemic negatively impacted overall time to surgery (TtS) as well as morbidity and mortality rates of hip fractures (HFx). METHODS: 416 patients treated for OTA 31 fractures at a single institution between January 2019 and November 2020 were reviewed. TtS as well as morbidity and mortality rates were obtained from pre-pandemic and pandemic groups. RESULTS: 263 patients were treated pre-pandemic and 153 were treated during the pandemic. There were no significant differences in median TtS, readmission rates (p = 0.134), reoperation rates (p = 0.052), 30-day (p = 0.095) and 90-day (p = 0.22) mortality rates. CONCLUSION: Reallocation of hospital resources in response to the COVID-19 pandemic did not negatively impact surgical timing or complications. TtS for HFx remains a challenge and often requires multidisciplinary care, which is complicated by a pandemic. However, this study demonstrates HFx standard of care can be maintained despite COVID-19 obstacles to treatment efficiency and efficacy.

Association of iron infusion reactions with ABO blood type.

OBJECTIVES: We sought to determine risk factors for iv iron infusion-related reactions (IRR), and identify strategies for iron repletion after IRR. METHODS: We conducted a retrospective chart review of patients treated in the classical hematology clinic at Yale Cancer Center (n = 330 consecutive patients) from 2016 to 2021, who received iv ferumoxytol (60.3%), iron sucrose (14.8%), or iron dextran (10.9%). RESULTS: The iv iron IRR was noted in 58 (17.6%) patients, 62.1% of whom had previously tolerated iv iron. The severity of IRR was mild in 22, moderate in 23, and severe in 11 patients. Most (72.4%) patients who experienced IRR tolerated a subsequent iv iron infusion. On multivariable analysis, a history of non-medication allergies was associated with greater odds of IRR (odds ratio [OR] 2.12, 95% confidence interval (CI): 1.16-3.87, p = .01). No patients with type AB blood, and few with type A blood (n = 6), had IRR; compared to type A or AB together, patients with type B (OR 5.00, 95% CI: 1.56-16.06, p = .007) or type O (OR 3.71, 95% CI: 1.44-9.55, p = .007) blood had greater odds of IRR. CONCLUSIONS: This study highlights a possible association of blood type with iv iron IRR; prospective studies with larger patient numbers are warranted to explore this association.

Blacktip shark Carcharhinus limbatus presence at fishing piers in South Carolina: association and environmental drivers.

We tagged 12 Carcharhinus limbatus with acoustic transmitters and monitored their presence at five piers along the north-east coast of South Carolina, USA in 2016 and four piers in 2017 using acoustic receivers. Data were analysed with pier association indices (PAI), mixed models and fast Fourier transformation analyses to identify potential factors related to residence time and presence at piers and any cyclical patterns in visits to piers. While the majority of monitored C. limbatus were infrequently detected at piers, three (25.0%) were highly associated with piers (PAI ≥ 0.50). Of the C. limbatus that were detected after initial capture, three (25.0%) recorded detection events only at the pier where they were tagged and two individuals (16.7%) recorded at least one detection event at all monitored piers. The best-fit model explaining C. limbatus residence time at piers included terms for pier location and diel cycle (wi = 0.88), whereas the best fit model explaining presence-absence of C. limbatus at piers included terms for tidal height, diel cycle, barometric pressure and angler count (wi = 0.98). Carcharhinus limbatus did not appear to display cyclical patterns in their visits to piers. Along the north-east coast of South Carolina, association of C. limbatus with piers is a phenomenon for a proportion of mature individuals, but continued research is necessary to understand if this behaviour is driven by attraction to and feeding on angler discards or increased foraging opportunities resulting from the attraction of potential prey to the physical structure provided by piers.

What is memory? The present state of the engram.

The mechanism of memory remains one of the great unsolved problems of biology. Grappling with the question more than a hundred years ago, the German zoologist Richard Semon formulated the concept of the engram, lasting connections in the brain that result from simultaneous "excitations", whose precise physical nature and consequences were out of reach of the biology of his day. Neuroscientists now have the knowledge and tools to tackle this question, however, and this Forum brings together leading contemporary views on the mechanisms of memory and what the engram means today.

GluA2 mRNA distribution and regulation by miR-124 in hippocampal neurons.

AMPA-type glutamate receptors mediate fast, excitatory neurotransmission in the brain, and their concentrations at synapses are important determinants of synaptic strength. We investigated the post-transcriptional regulation of GluA2, the calcium-impermeable AMPA receptor subunit, by examining the subcellular distribution of its mRNA and evaluating its translational regulation by microRNA in cultured mouse hippocampal neurons. Using computational approaches, we identified a conserved microRNA-124 (miR-124) binding site in the 3'UTR of GluA2 and demonstrated that miR-124 regulated the translation of GluA2 mRNA reporters in a sequence-specific manner in luciferase assays. While we hypothesized that this regulation might occur in dendrites, our biochemical and fluorescent in situ hybridization (FISH) data indicate that GluA2 mRNA does not localize to dendrites or synapses of mouse hippocampal neurons. In contrast, we detected significant concentrations of miR-124 in dendrites. Overexpression of miR-124 in dissociated neurons results in a 30% knockdown of GluA2 protein, as measured by immunoblot and quantitative immunocytochemistry, without producing any changes in GluA2 mRNA concentrations. While total GluA2 concentrations are reduced, we did not detect any changes in the concentration of synaptic GluA2. We conclude from these results that miR-124 interacts with GluA2 mRNA in the cell body to downregulate translation. Our data support a model in which GluA2 is translated in the cell body and subsequently transported to neuronal dendrites and synapses, and suggest that synaptic GluA2 concentrations are modified primarily by regulated protein trafficking rather than by regulated local translation.

Identification of a cis-acting element that localizes mRNA to synapses.

Messenger RNA (mRNA) localization and regulated translation can spatially restrict gene expression to each of the thousands of synaptic compartments formed by a single neuron. Although cis-acting RNA elements have been shown to direct localization of mRNAs from the soma into neuronal processes, less is known about signals that target transcripts specifically to synapses. In Aplysia sensory-motor neuronal cultures, synapse formation rapidly redistributes the mRNA encoding the peptide neurotransmitter sensorin from neuritic shafts into synapses. We find that the export of sensorin mRNA from soma to neurite and the localization to synapse are controlled by distinct signals. The 3' UTR is sufficient for export into distal neurites, whereas the 5' UTR is required for concentration of reporter mRNA at synapses. We have identified a 66-nt element in the 5' UTR of sensorin that is necessary and sufficient for synaptic mRNA localization. Mutational and chemical probing analyses are consistent with a role for secondary structure in this process.

Do people keep believing because they want to? Preexisting attitudes and the continued influence of misinformation.

Misinformation-defined as information that is initially assumed to be valid but is later corrected or retracted-often has an ongoing effect on people's memory and reasoning. We tested the hypotheses that (a) reliance on misinformation is affected by people's preexisting attitudes and (b) attitudes determine the effectiveness of retractions. In two experiments, participants scoring higher and lower on a racial prejudice scale read a news report regarding a robbery. In one scenario, the suspects were initially presented as being Australian Aboriginals, whereas in a second scenario, a hero preventing the robbery was introduced as an Aboriginal person. Later, these critical, race-related pieces of information were or were not retracted. We measured participants' reliance on misinformation in response to inferential reasoning questions. The results showed that preexisting attitudes influence people's use of attitude-related information but not the way in which a retraction of that information is processed.

The balance between antiviral and antibacterial responses during M. tuberculosis infection is regulated by the ubiquitin ligase CBL.

As a first line of host defense, macrophages must be able to effectively sense and respond to diverse types of pathogens, and while a particular type of immune response may be beneficial in some circumstances, it can be detrimental in others. Upon infecting a macrophage, M. tuberculosis (Mtb) induces proinflammatory cytokines that activate antibacterial responses. Surprisingly, Mtb also triggers antiviral responses that actually hinder the ability of macrophages to control Mtb infection. The ubiquitin ligase CBL suppresses these antiviral responses and shifts macrophages toward a more antibacterial state during Mtb infection, however, the mechanisms by which CBL regulates immune signaling are unknown. We found that CBL controls responses to multiple stimuli and broadly suppresses the expression of antiviral effector genes. We then used mass-spectrometry to investigate potential CBL substrates and identified over 46,000 ubiquitylated peptides in Mtb-infected macrophages, as well as roughly 400 peptides with CBL-dependent ubiquitylation. We then performed genetic interaction analysis of CBL and its putative substrates, and identified the Fas associated factor 2 (FAF2) adapter protein as a key signaling molecule protein downstream of CBL. Together, these analyses identify thousands of new ubiquitin-mediated signaling events during the innate immune response and reveal an important new regulatory hub in this response.

Trends in functional outcome measures in orthopedic oncology.

The purpose of this study was to identify trends in the use of functional outcome measures within orthopedic oncology. The search engine, PubMed, was reviewed for all articles over an 11-year period from 2011 to 2021 from five major journals that publish in the field of orthopedic oncology. The functional outcome measures used in the articles were recorded along with study date, study design, clinical topic/pathology, and level of evidence. Out of 5968 musculoskeletal tumor-focused articles reviewed, 293 (4.9%) included at least one outcome measure. A total of 28 different outcome tools were identified. The most popular were Musculoskeletal Tumor Society (MSTS) score (61.1%) and Toronto Extremity Salvage (TESS) score (14.0%), followed by 36-Item Short Form Survey (SF-36) (4.1%) and Patient-Reported Outcomes Measurement Information System (PROMIS) (3.8%). The use of MSTS scores decreased by 0.7% each year, whereas PROMIS increased by 1.2% each year. Seventy-four articles used more than one outcome measure. Of these 74 articles, 61 had the MSTS as one of the outcome measures. Orthopedic oncology utilizes functional outcome measures less commonly in comparison to other orthopedic subspecialties. However, this may be due in large part to orthopedic oncologists putting more emphasis on outcomes such as local recurrence, implant failure, and mortality. MSTS score is the most widely used functional outcome measure, but the utilization of PROMIS has increased recently, and could be the next step in evaluating outcomes in orthopedic oncology as it is patient-derived rather than physician-derived.

Aging differentially alters the transcriptome and landscape of chromatin accessibility in the male and female mouse hippocampus.

Aging-related memory impairment and pathological memory disorders such as Alzheimer's disease differ between males and females, and yet little is known about how aging-related changes in the transcriptome and chromatin environment differ between sexes in the hippocampus. To investigate this question, we compared the chromatin accessibility landscape and gene expression/alternative splicing pattern of young adult and aged mouse hippocampus in both males and females using ATAC-seq and RNA-seq. We detected significant aging-dependent changes in the expression of genes involved in immune response and synaptic function and aging-dependent changes in the alternative splicing of myelin sheath genes. We found significant sex-bias in the expression and alternative splicing of hundreds of genes, including aging-dependent female-biased expression of myelin sheath genes and aging-dependent male-biased expression of genes involved in synaptic function. Aging was associated with increased chromatin accessibility in both male and female hippocampus, especially in repetitive elements, and with an increase in LINE-1 transcription. We detected significant sex-bias in chromatin accessibility in both autosomes and the X chromosome, with male-biased accessibility enriched at promoters and CpG-rich regions. Sex differences in gene expression and chromatin accessibility were amplified with aging, findings that may shed light on sex differences in aging-related and pathological memory loss.

Delta-8-Tetrahydrocannabinol Exposure and Confirmation in Four Pediatric Patients.

INTRODUCTION: Delta-8-tetrahydrocannabinol (THC) is a known isomer of delta-9-THC, both found naturally in the Cannabis sativa plant and thought to have similar potency. Delta-8-THC products are widely accessible in retail shops which may lead to a rise in pediatric exposures with substantial clinical effects. CASE REPORT: This is a case series of four pediatric patients that were seen between June and September 2021. The patients presented with varied clinical symptoms including confusion, somnolence, seizure-like activity, hypotension, and tachycardia after exposure to delta-8-THC products obtained in retail shops. Basic urine drug screen immunoassays revealed positive results for cannabinoids in all patients. Subsequent confirmatory drug analysis of residual biological samples of blood and/or urine was sent to the University of California San Francisco Clinical Toxicology and Environment Biomonitoring Laboratory with the assistance of the Drug Enforcement Administration's Toxicology Testing Program (DEA TOX). Confirmatory testing revealed 11-nor-9-carboxy-delta-8-THC, the metabolite of delta-8-THC. Delta-9-THC and its metabolites were not detected on confirmatory testing in any of the cases. DISCUSSION: Clinical effects of delta-8-THC in children include but are not limited to altered mental status, seizure-like activity, and vital sign abnormalities. Delta-8-THC exposure may lead to a positive urine drug screen for cannabinoids, but confirmatory testing is needed to differentiate from delta-9-THC.

A rapid and bidirectional reporter of neural activity reveals neural correlates of social behaviors in Drosophila.

Neural activity is modulated over different timescales encompassing subseconds to hours, reflecting changes in external environment, internal state and behavior. Using Drosophila as a model, we developed a rapid and bidirectional reporter that provides a cellular readout of recent neural activity. This reporter uses nuclear versus cytoplasmic distribution of CREB-regulated transcriptional co-activator (CRTC). Subcellular distribution of GFP-tagged CRTC (CRTC::GFP) bidirectionally changes on the order of minutes and reflects both increases and decreases in neural activity. We established an automated machine-learning-based routine for efficient quantification of reporter signal. Using this reporter, we demonstrate mating-evoked activation and inactivation of modulatory neurons. We further investigated the functional role of the master courtship regulator gene fruitless (fru) and show that fru is necessary to ensure activation of male arousal neurons by female cues. Together, our results establish CRTC::GFP as a bidirectional reporter of recent neural activity suitable for examining neural correlates in behavioral contexts.

Tumor-to-Tumor Metastasis: Renal Cell Carcinoma Metastasizing to a Lipoma of the Thigh: A Case Report.

CASE: A 73-year-old man with a medical history significant for renal cell carcinoma (RCC) presented with widespread osseous metastases and imaging suspicious for RCC metastasizing to a lipoma interdigitated within the right vastus lateralis. The patient's pathological fractures were surgically addressed, and the lipoma excised. Final histology revealed a thigh lipoma involved by metastatic RCC without direct extension. CONCLUSION: Tumor-to-tumor metastasis is a rare occurrence, with RCC typically being the most common "recipient" tumor. This is the first case to the best of our knowledge of RCC metastasizing to a lipoma, highlighting a rare phenomena in a patient with metastatic disease.

Analysis of Ceftazidime/Avibactam Use for Treating Carbapenem-Resistant Infections in Critically Ill Patients With Thermal or Inhalation Injuries.

Rising antimicrobial resistance is a pressing public health concern. An increase in carbapenem-resistant organisms has led to increased use of novel antibiotics, such as ceftazidime/avibactam (CZ/AV). However, recent studies have shown increasing treatment failures and resistance rates associated with ceftazidime/avibactam use. The efficacy of CZ/AV has not been studied in patients with thermal or inhalation injuries, where pharmacokinetic derangements are common and patients are often subject to longer lengths of stay and several antimicrobial courses that may lead to higher resistance rates. The objective of this study was to evaluate the outcomes of patients with thermal and inhalation injuries including clinical success, the frequency of adverse effects, and emergence of resistance. In the 17 courses of CZ/AV evaluated, clinical success occurred in 71% (12/17) of courses. Enterobacter cloacae was the most commonly treated pathogen. Resistance developed in 18% (3/17) of courses, but follow-up sensitivities were not evaluable for every case. Although lower than desired, clinical success rates in this sample were similar to other reported populations treated with CZ/AV. However, the emergence of resistance occurred more frequently and was likely underreported in this sample. Although limited by its small sample size, this study emphasizes the concern of growing antimicrobial resistance among even novel antibiotics. Resistance can develop during the initial course, stressing the importance of infection prevention and antimicrobial stewardship. Furthermore, attention and resources should be given to proper pharmacokinetic analysis of medications given in severely ill, hypermetabolic populations.