Solvent Minimized Synthesis of Amides by Reactive Extrusion.

Herein, we report on the translation of a small scale ball-milled amidation protocol into a large scale continuous reactive extrusion process. Critical components to the successful translation were: a) understanding how the different operating parameters of a twin-screw extruder should be harnessed to control prolonged continuous operation, and b) consideration of the physical form of the input materials. The amidation reaction is applied to 36 amides spanning a variety of physical form combinations (liquid-liquid, solid-liquid and solid-solid). Following this learning process, we have developed an understanding for the translation of each physical form combination and demonstrated a 7-hour reactive extrusion process for the synthesis of an amide on 500 gram scale (1.3 mols of product).

Mid-term Waitlist and Posttransplant Outcomes With Hepatitis C-positive Donor Hearts.

BACKGROUND: This study evaluates the clinical trends and impact of hepatitis C virus-positive (HCV+) donors on waitlist and posttransplant outcomes after heart transplantation. METHODS: The United Network for Organ Sharing registry was queried to identify adult waitlisted and transplanted patients from January 1, 2015, to December 31, 2022. In the waitlist analysis, the candidates were stratified into 2 cohorts based on whether they were willing to accept HCV+ donor offers. Waitlist outcomes included 1-y cumulative incidences of transplantation and death/delisting. In the posttransplant analysis, the recipients were stratified into 2 cohorts with and without HCV nucleic acid test (NAT)-positive donors. Outcomes included 1- and 4-y posttransplant survival. Propensity score-matching was performed. Risk adjustment was performed using multivariable Cox regression. RESULTS: During the study period, the number of centers using HCV NAT+ donors increased from 1 to 65 centers, along with the number of transplants. In the waitlist analysis, 26 648 waitlisted candidates were analyzed, and 4535 candidates (17%) were approved to accept HCV+ donors. Approval to accept HCV+ donors was associated with a higher likelihood of transplantation and a lower likelihood of death/delisting within 1 y of waitlisting. In the posttransplant analysis, 21 131 recipients were analyzed, and 997 recipients (4.7%) received HCV NAT+ hearts. The 1- and 4-y posttransplant survival were comparable between the recipients of HCV NAT+ and NAT- donors. Furthermore, the similar 1- and 4-y posttransplant survival persisted in the propensity score-matched comparison and multivariable Cox regression analysis. CONCLUSIONS: Utilization of HCV+ donors is rising. Heart transplants using HCV+ donors are associated with improved waitlist and comparable posttransplant outcomes.

Serial Shock Severity Assessment Within 72 Hours After Diagnosis: A Cardiogenic Shock Working Group Report.

BACKGROUND: The Cardiogenic Shock Working Group-modified Society for Cardiovascular Angiography and Interventions (CSWG-SCAI) staging was developed to risk stratify cardiogenic shock (CS) severity. Data showing progressive changes in SCAI stages and outcomes are limited. OBJECTIVES: We investigated serial changes in CSWG-SCAI stages and outcomes of patients presenting with cardiogenic shock complicating acute myocardial infarction (MI-CS) and heart failure-related CS (HF-CS). METHODS: The multicenter CSWG registry was queried. CSWG-SCAI stages were computed at CS diagnosis and 24, 48, and 72 hours. RESULTS: A total of 3,268 patients (57% HF-CS; 27% MI-CS) were included. At CS diagnosis, CSWG-SCAI stage breakdown was 593 (18.1%) stage B, 528 (16.2%) stage C, 1,659 (50.8%) stage D, and 488 (14.9%) noncardiac arrest stage E. At 24 hours, >50% of stages B and C patients worsened, but 86% of stage D patients stayed at stage D. Among stage E patients, 54% improved to stage D and 36% stayed at stage E by 24 hours. Minimal SCAI stage changes occurred beyond 24 hours. SCAI stage trajectories were similar between MI-CS and HF-CS groups. Within 24 hours, unadjusted mortality rates of patients with any SCAI stage worsening or improving were 44.6% and 34.2%, respectively. Patients who presented in or progressed to stage E by 24 hours had the worst prognosis. Survivors had lower lactate than nonsurvivors. CONCLUSIONS: Most patients with CS changed SCAI stages within 24 hours from CS diagnosis. Stage B patients were at high risk of worsening shock severity by 24 hours, associated with excess mortality. Early CS recognition and serial assessment may improve risk stratification.

Evolving Trends and Impact of Waitlist Transfusion on Recipient Outcomes Following Heart Transplantation.

BACKGROUND: This study evaluates the clinical trends, risk factors, and impact of waitlist blood transfusion on outcomes following isolated heart transplantation. METHODS: The UNOS registry was queried to identify adult recipients from January 1, 2014, to June 30, 2022. The recipients were stratified into two groups depending on whether they received a blood transfusion while on the waitlist. The incidence of waitlist transfusion was compared before and after the 2018 allocation policy change. The primary outcome was survival. Propensity score-matching was performed. Multivariable logistic regression was performed to identify predictors of waitlist transfusion. A sub-analysis was performed to evaluate the impact of waitlist time on waitlist transfusion. RESULTS: From the 21 926 recipients analyzed in this study, 4201 (19.2%) received waitlist transfusion. The incidence of waitlist transfusion was lower following the allocation policy change (14.3% vs. 23.7%, p < 0.001). The recipients with waitlist transfusion had significantly reduced 1-year posttransplant survival (88.8% vs. 91.9%, p < 0.001) compared to the recipients without waitlist transfusion in an unmatched comparison. However, in a propensity score-matched comparison, the two groups had similar 1-year survival (90.0% vs. 90.4%, p = 0.656). Multivariable analysis identified ECMO, Impella, and pretransplant dialysis as strong predictors of waitlist transfusion. In a sub-analysis, the odds of waitlist transfusion increased nonlinearly with longer waitlist time. CONCLUSION: There is a lower incidence of waitlist transfusion among transplant recipients under the 2018 allocation system. Waitlist transfusion is not an independent predictor of adverse posttransplant outcomes but rather a marker of the patient's clinical condition. ECMO, Impella, and pretransplant dialysis are strong predictors of waitlist transfusion.

Extended Duration of Impella 5.5 Support Does Not Adversely Impact Outcomes Following Heart Transplantation: A National Registry Analysis.

Prior studies assessing the effects of Impella 5.5 support duration on posttransplant outcomes have been limited to single-center case reports and series. This study evaluates the impact of Impella 5.5 support duration on outcomes following heart transplantation using the United Network for Organ Sharing database. Adult heart transplant recipients who were directly bridged to primary isolated heart transplantation with Impella 5.5 were included. The cohort was stratified into two groups based on the duration of Impella support: less than or equal to 14 and greater than 14 days. The primary outcome was 90 day posttransplant survival. Propensity score matching was performed. Sub-analysis was conducted to evaluate the impact of greater than 30 days of Impella support on 90 day survival. Three hundred thirty-two recipients were analyzed. Of these, 212 recipients (63.9%) were directly bridged to heart transplantation with an Impella support duration of greater than 14 days. The two groups had comparable 90 day posttransplant survival and complication rates. The comparable posttransplant survival persisted in a propensity score-matched comparison. In the sub-analysis, Impella support duration of greater than or equal to 30 days did not adversely impact 90 day survival. This study demonstrates that extended duration of support with Impella 5.5 as a bridge to transplantation does not adversely impact posttransplant outcomes. Impella 5.5 is a safe and effective bridging modality to heart transplantation.

Donor and Recipient Age Influence Outcomes Following Orthotopic Heart Transplantation in the 2018 US Heart Allocation System.

BACKGROUND: This study evaluates the interaction of donor and recipient age with outcomes following heart transplantation under the 2018 heart allocation system. METHODS: The United Network for Organ Sharing registry was queried to analyze adult primary isolated orthotopic heart transplant recipients and associated donors from August 18, 2018, to June 30, 2021. Both recipient and donor cohorts were grouped according to age: <65 and ≥65 y for recipients and <50 and ≥50 y for donors. The primary outcome was survival. Subanalyses were performed to evaluate the impact of donor age. RESULTS: A total of 7601 recipients and 7601 donors were analyzed. Of these, 1584 recipients (20.8%) were ≥65 y old and 560 donors (7.4%) were ≥50 y old. Compared with recipients <65, recipients ≥65 had decreased 1-y (88.8% versus 92.3%) and 2-y (85.1% versus 88.5%) survival rates (P < 0.001). The association of recipient age ≥65 with lower survival persisted after adjusting for potential cofounders (hazard ratio, 1.38; 95% confidence interval, 1.18-1.61; P < 0.001). Recipients <65 with donors ≥50 had comparable 1-y and 2-y survival rates to recipients <65 with donors <50 (P =0.997). Conversely, transplantation of older allografts was associated with lower 1-y (84.2% versus 89.4%) and 2-y (79.5% versus 85.8%) survival rates in recipients ≥65 (P = 0.025). CONCLUSIONS: Recipient age ≥65 continues to be associated with worse survival following heart transplantation in the 2018 heart allocation system compared with younger recipients. Donors ≥50 may be acceptable among recipients <65 with comparable outcomes. However, careful donor age selection should be considered for recipients ≥65, as the use of younger donor allografts appears to improve posttransplantation survival.

Progressive Paracentral Visual Field Loss at Low Intraocular Pressures Following LASIK.

Intraocular pressure is currently the only known reliable, modifiable risk factor for the development and progression of glaucoma. Other risk factors for glaucoma include increasing age, myopia, decreased central corneal thickness, and low corneal hysteresis (CH) measurements. Photoablative keratorefractive surgery including laser assisted in situ keratomileusis (LASIK) has become a common way to treat refractive error, with over 25 million procedures performed in the United States alone. Though myopic LASIK has been associated with a decrease in CH measurements, relatively little is known about the risk of LASIK on glaucoma onset and progression. Here we present an observational study of 4 consecutive relatively young and otherwise healthy glaucoma patients with a history of myopic LASIK who showed progression of paracentral visual field deficits at intraocular pressures of 12 mm Hg or less while being carefully monitored. Therefore, these patients required lower targets of intraocular pressure, in the single-digit range, to slow or halt progression. In this cohort, the average corneal hysteresis was more than 2 standard deviations below normal values. This series suggests that additional study into the association of LASIK and glaucoma is warranted, including the potential risk contribution of diminished CH. These studies may be particularly relevant as patients who underwent LASIK procedures in the early 2000s may now be at increased risk of glaucoma due to the risk factor of age.

Hemin-Induced Transient Senescence Via DNA Damage Response: A Neuroprotective Mechanism Against Ferroptosis in Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) poses acute fatality and long-term neurological risks due to hemin and iron accumulation from hemoglobin breakdown. Our observation that hemin induces DNA double-strand breaks (DSBs), prompting a senescence-like phenotype in neurons, necessitating deeper exploration of cellular responses. Using experimental ICH models and human ICH patient tissue, we elucidate hemin-mediated DNA damage response (DDR) inducing transient senescence and delayed expression of heme oxygenase (HO-1). HO-1 co-localizes with senescence-associated ß-Galactosidase (SA-ß-Gal) in ICH patient tissues, emphasizing clinical relevance of inducible HO-1 expression in senescent cells. We reveal a reversible senescence state protective against acute cell death by hemin, while repeat exposure leads to long-lasting senescence. Inhibiting early senescence expression increases cell death, supporting the protective role of senescence against hemin toxicity. Hemin-induced senescence is attenuated by a pleiotropic carbon nanoparticle that is a catalytic mimic of superoxide dismutase, but this treatment increased lipid peroxidation, consistent with ferroptosis from hemin breakdown released iron. When coupled with iron chelator deferoxamine (DEF), the nanoparticle reduces hemin-induced senescence and upregulates factors protecting against ferroptosis. Our study suggests transient senescence induced by DDR as an early potential neuroprotective mechanism in ICH, but the risk or iron-related toxicity supports a multi-pronged therapeutic approach.

Deficiency of m 6 A RNA methylation promotes ZBP1-mediated cell death.

m 6 A RNA methylation suppresses the immunostimulatory potential of endogenous RNA. Deficiency of m 6 A provokes inflammatory responses and cell death, but the underlying mechanisms remain elusive. Here we showed that the noncoding RNA 7SK gains immunostimulatory potential upon m 6 A depletion and subsequently activates the RIG-I/MAVS axis to spark interferon (IFN) signaling cascades. Concomitant excess of IFN and m 6 A deficiency synergistically facilitate the formation of RNA G-quadruplexes (rG4) to promote ZBP1-mediated necroptotic cell death. Collectively, our findings delineate a hitherto uncharacterized mechanism that links m 6 A dysregulation with ZBP1 activity in triggering inflammatory cell death.

Fragment-Based Discovery of Novel MUS81 Inhibitors.

MUS81 is a structure-selective endonuclease that cleaves various branched DNA structures arising from natural physiological processes such as homologous recombination and mitosis. Due to this, MUS81 is able to relieve replication stress, and its function has been reported to be critical to the survival of many cancers, particularly those with dysfunctional DNA-repair machinery. There is therefore interest in MUS81 as a cancer drug target, yet there are currently few small molecule inhibitors of this enzyme reported, and no liganded crystal structures are available to guide hit optimization. Here we report the fragment-based discovery of novel small molecule MUS81 inhibitors with sub-µM biochemical activity. These inhibitors were used to develop a novel crystal system, providing the first structural insight into the inhibition of MUS81 with small molecules.

Pain management of adult sedated and ventilated patients in the intensive care units: A survey with free text responses.

BACKGROUND: Pain management of sedated and ventilated patients in intensive care units lacks consistency. OBJECTIVES: To investigate nurses' training, governance, practices, knowledge and attitudes relating to pain management in consideration of published guidelines and explore nurses' perspectives. METHODS: A survey design, using an online questionnaire with free text responses, was employed. Quantitative and qualitative data from nurses working across different hospitals were collated and saved on Qualtrics platform. Quantitative data were analysed non-parametrically and narrative responses thematically. CROSS and SRQR reporting guidelines were adhered to. OUTCOME MEASURES: Demographics, training, governance, clinical practice, knowledge, and attitudes. RESULTS/FINDINGS: 108 nurses participated with ninety-two completed surveys analysed. Analgesia was used to complete nursing tasks regardless of comfort needs (n = 49, 53.3 %). Changes in vital signs prompted opioid administration (n = 48, 52.1 %). Choice of analgesia depended on doctor's preference (n = 63, 68.5 %). Non-opioid therapy was administered before opioids (n = 42, 45.7 %). Sedatives were used to alleviate agitation(n = 50,54.3 %). No statistically significant difference in nurses' knowledge existed between hospitals. Weak positive relationship: r = [0.081], p = [0.441] between "knowledge scores" and "years of ICU experience" and weak negative relationship r = [-0.119], p = [0.260] between "knowledge scores" and "hours of clinical practice" was detected. Lack of training, resources, policies, high patient acuity and casual employment were acknowledged barriers to pain management. Two overarching themes emerged from narrative responses: "Pain assessment, where is it?" And "Priorities of critical illness." CONCLUSION: The study uncovered pain management situation and examined nurses' demographics, training, governance, practices, knowledge and attitudes. Narrative responses highlighted barriers to pain management. IMPLICATIONS FOR CLINICAL PRACTICE: Health organisations should provide education, institute governance and develop policies to inform pain management. Nurses' role encompasses updating knowledge, adhering to interventions and overcoming biases. This subsequently manifests as improvement in patient outcomes.

Clinical outcomes among cardiogenic shock patients supported with high-capacity Impella axial flow pumps: A report from the Cardiogenic Shock Working Group.

BACKGROUND: The Impella 5.0 and 5.5 pumps (Abiomed, Danvers, MA) are large-bore transvalvular micro-axial assist devices used in cardiogenic shock (CS) for patients requiring high-capacity flow. Despite their increasing use, real-world data regarding indications, rates of utilization and clinical outcomes with this therapy are limited. The objective of our study was to examine clinical profiles and outcomes of patients in a contemporary, real-world CS registry of patients who received an Impella 5.0/5.5 alone or in combination with other temporary mechanical circulatory support (tMCS) devices. METHODS: The CS Working Group (CSWG) Registry includes patients from 34 US hospitals. For this analysis, data from patients who received an Impella 5.0/5.5 between 2020-2023 were analyzed. Use of Impella 5.0/5.5 with or without additional tMCS therapies, duration of support, adverse events and outcomes at hospital discharge were studied. Adverse events including stroke, limb ischemia, bleeding and hemolysis were not standardized by the registry but reported per individual CSWG Primary Investigator discretion. For those who survived, rates of native heart recovery (NHR) or heart replacement therapy (HRT) including heart transplant (HT), or durable ventricular assist device (VAD) were recorded. We also assessed outcomes based on shock etiology (acute myocardial infarction or MI-CS vs. heart failure-related CS or HF-CS). RESULTS: Among 6,205 patients, 754 received an Impella 5.0/5.5 (12.1%), including 210 MI-CS (27.8%) and 484 HF-CS (64.1%) patients. Impella 5.0/5.5 was used as the sole tMCS device in 32% of patients, while 68% of patients received a combination of tMCS devices. Impella cannulation sites were available for 524/754 (69.4%) of patients, with 93.5% axillary configuration. Survival to hospital discharge for those supported with an Impella 5.0/5.5 was 67%, with 20.4% NHR and 45.5% HRT. Compared to HF-CS, patients with MI-CS supported on Impella 5.0/5.5 had higher in-hospital mortality (45.2% vs 26.2%, p < 0.001) and were less likely to receive HRT (22.4% vs 56.6%, p < 0.001. For patients receiving a combination of tMCS during hospitalization, this was associated with higher rates of limb ischemia (9% vs. 3%, p < 0.01), bleeding (52% vs 33%, p < 0.01), and mortality (38% vs 25%; p < 0.001) compared to Impella 5.0/5.5 alone. Among Impella 5.0/5.5 recipients, the median duration of pump support was 12.9 days (IQR: 6.8-22.9) and longer in patients bridged to HRT (14 days; IQR: 7.7-28.4). CONCLUSIONS: In this multi-center cohort of patients with CS, use of Impella 5.0/5.5 was associated with an overall survival of 67.1% and high rates of HRT. Lower adverse event rates were observed when Impella 5.0/5.5 was the sole support device used. Further study is required to determine whether a strategy of early Impella 5.0/5.5 use for CS improves survival. CONDENSED ABSTRACT: High capacity Impella heart pumps are capable of provide up to 5.5 liter/min of flow while upper body surgical placement allows for ambulation. Patients with advanced cardiogenic shock from acute myocardial infarction or heart failure requiring temporary mechanical circulatory support may benefit from upfront use of Impella 5.5 to improve overall survival, including native heart recovery or successful bridge to durable left ventricular assist device surgery or heart transplantation.

Factors associated with acute limb ischemia in cardiogenic shock and downstream clinical outcomes: Insights from the Cardiogenic Shock Working Group.

BACKGROUND: There are limited data depicting the prevalence and ramifications of acute limb ischemia (ALI) among cardiogenic shock (CS) patients. METHODS: We employed data from the Cardiogenic Shock Working Group (CSWG), a consortium including 33 sites. We constructed a multi-variable logistic regression to examine the association between clinical factors and ALI, we generated another logistic regression model to ascertain the association of ALI with mortality. RESULTS: There were 7,070 patients with CS and 399 (5.6%) developed ALI. Patients with ALI were more likely to be female (40.4% vs 29.4%) and have peripheral arterial disease (13.8% vs 8.3%). Stratified by maximum society for cardiovascular angiography & intervention (SCAI) shock stage, the rates of ALI were stage B 0.0%, stage C 1.8%, stage D 4.1%, and stage E 10.3%. Factors associated with higher risk for ALI included: peripheral vascular disease OR 2.24 (95% CI: 1.53-3.23; p < 0.01) and ≥2 mechanical circulatory support (MCS) devices OR 1.66 (95% CI: 1.24-2.21, p < 0.01). ALI was highest for venous-arterial extracorporeal membrane oxygenation (VA-ECMO) patients (11.6%) or VA-ECMO+ intra-aortic balloon pump (IABP)/Impella CP (16.6%) yet use of distal perfusion catheters was less than 50%. Mortality was 38.0% for CS patients without ALI but 57.4% for CS patients with ALI. ALI was significantly associated with mortality, adjusted OR 1.40 (95% CI 1.01-1.95, p < 0.01). CONCLUSIONS: The rate of ALI was 6% among CS patients. Factors most associated with ALI include peripheral vascular disease and multiple MCS devices. The downstream ramifications of ALI were dire with a considerably higher risk of mortality.

Identification of Novel Potent NSD2-PWWP1 Ligands Using Structure-Based Design and Computational Approaches.

Dysregulation of histone methyl transferase nuclear receptor-binding SET domain 2 (NSD2) has been implicated in several hematological and solid malignancies. NSD2 is a large multidomain protein that carries histone writing and histone reading functions. To date, identifying inhibitors of the enzymatic activity of NSD2 has proven challenging in terms of potency and SET domain selectivity. Inhibition of the NSD2-PWWP1 domain using small molecules has been considered as an alternative approach to reduce NSD2-unregulated activity. In this article, we present novel computational chemistry approaches, encompassing free energy perturbation coupled to machine learning (FEP/ML) models as well as virtual screening (VS) activities, to identify high-affinity NSD2 PWWP1 binders. Through these activities, we have identified the most potent NSD2-PWWP1 binder reported so far in the literature: compound 34 (pIC50 = 8.2). The compounds identified herein represent useful tools for studying the role of PWWP1 domains for inhibition of human NSD2.

RNA/DNA Binding Protein TDP43 Regulates DNA Mismatch Repair Genes with Implications for Genome Stability.

TDP43 is an RNA/DNA binding protein increasingly recognized for its role in neurodegenerative conditions including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). As characterized by its aberrant nuclear export and cytoplasmic aggregation, TDP43 proteinopathy is a hallmark feature in over 95% of ALS/FTD cases, leading to the formation of detrimental cytosolic aggregates and a reduction in nuclear functionality within neurons. Building on our prior work linking TDP43 proteinopathy to the accumulation of DNA double-strand breaks (DSBs) in neurons, the present investigation uncovers a novel regulatory relationship between TDP43 and DNA mismatch repair (MMR) gene expressions. Here, we show that TDP43 depletion or overexpression directly affects the expression of key MMR genes. Alterations include MLH1, MSH2, MSH3, MSH6, and PMS2 levels across various primary cell lines, independent of their proliferative status. Our results specifically establish that TDP43 selectively influences the expression of MLH1 and MSH6 by influencing their alternative transcript splicing patterns and stability. We furthermore find aberrant MMR gene expression is linked to TDP43 proteinopathy in two distinct ALS mouse models and post-mortem brain and spinal cord tissues of ALS patients. Notably, MMR depletion resulted in the partial rescue of TDP43 proteinopathy-induced DNA damage and signaling. Moreover, bioinformatics analysis of the TCGA cancer database reveals significant associations between TDP43 expression, MMR gene expression, and mutational burden across multiple cancers. Collectively, our findings implicate TDP43 as a critical regulator of the MMR pathway and unveil its broad impact on the etiology of both neurodegenerative and neoplastic pathologies.

Beta blockers are associated with lower all-cause mortality among HFpEF patients.

BACKGROUND: The evidence regarding beta blocker (BB) benefit in heart failure with preserved ejection fraction (HFpEF) remains inconclusive, leading to consideration of BB withdrawal in this population. OBJECTIVES: In this study, we retrospectively analyzed the association of BB on all-cause mortality in HFpEF patients. METHODS: This is a single-center retrospective cohort study of 20,206 patients with left ventricular ejection fraction (EF) ≥ 50% who were hospitalized with decompensated HF between January 2011 and March 2020. Survival is reported at 30 days, 1 year, and 3 years. A secondary analysis comparing mortality for patients on BB with additional indications including hypertension (HTN), coronary artery disease (CAD), and atrial fibrillation (AF) was completed. Mortality was compared between patients on BB and additional therapies of spironolactone or angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEi/ARBs). RESULTS: BB showed lower all-cause mortality at 30 days, 1 year, and 3 years (p < 0.0001). This association with lower all-cause mortality was validated by a supplementary propensity score-matched analysis. At 3 years, there was significant mortality reduction with addition of BB to either spironolactone (p = 0.0359) or ACEi/ARBs (p < 0.0001). CONCLUSION: In a large single-center retrospective registry, BB use was associated with lower mortality in HFpEF patients with a recent decompensated HF hospitalization. The mortality benefit persisted in those treated with spironolactone or ACEi/ARBs, and in those with AF. This provocative data further highlights the uncertainty of the benefit of BB use in this cohort and calls for re-consideration of BB withdrawal, especially in those tolerating it well, without conclusive, large, and randomized trials showing lack of benefit or harm.

CRISPR-Cas Genome Editing in Ex Vivo Human Lungs to Rewire the Translational Path of Genome-Targeting Therapeutics.

The ongoing advancements in CRISPR-Cas technologies can significantly accelerate the preclinical development of both in vivo and ex vivo organ genome-editing therapeutics. One of the promising applications is to genetically modify donor organs prior to implantation. The implantation of optimized donor organs with long-lasting immunomodulatory capacity holds promise for reducing the need for lifelong potent whole-body immunosuppression in recipients. However, assessing genome-targeting interventions in a clinically relevant manner prior to clinical trials remains a major challenge owing to the limited modalities available. This study introduces a novel platform for testing genome editing in human lungs ex vivo, effectively simulating preimplantation genetic engineering of donor organs. We identified gene regulatory elements whose disruption via Cas nucleases led to the upregulation of the immunomodulatory gene interleukin 10 (IL-10). We combined this approach with adenoviral vector-mediated IL-10 delivery to create favorable kinetics for early (immediate postimplantation) graft immunomodulation. Using ex vivo organ machine perfusion and precision-cut tissue slice technology, we demonstrated the feasibility of evaluating CRISPR genome editing in human lungs. To overcome the assessment limitations in ex vivo perfused human organs, we conducted an in vivo rodent study and demonstrated both early gene induction and sustained editing of the lung. Collectively, our findings lay the groundwork for a first-in-human-organ study to overcome the current translational barriers of genome-targeting therapeutics.

Library Screening, In Vivo Confirmation, and Structural and Bioinformatic Analysis of Pentapeptide Sequences as Substrates for Protein Farnesyltransferase.

Protein farnesylation is a post-translational modification where a 15-carbon farnesyl isoprenoid is appended to the C-terminal end of a protein by farnesyltransferase (FTase). This process often causes proteins to associate with the membrane and participate in signal transduction pathways. The most common substrates of FTase are proteins that have C-terminal tetrapeptide CaaX box sequences where the cysteine is the site of modification. However, recent work has shown that five amino acid sequences can also be recognized, including the pentapeptides CMIIM and CSLMQ. In this work, peptide libraries were initially used to systematically vary the residues in those two parental sequences using an assay based on Matrix Assisted Laser Desorption Ionization-Mass Spectrometry (MALDI-MS). In addition, 192 pentapeptide sequences from the human proteome were screened using that assay to discover additional extended CaaaX-box motifs. Selected hits from that screening effort were rescreened using an in vivo yeast reporter protein assay. The X-ray crystal structure of CMIIM bound to FTase was also solved, showing that the C-terminal tripeptide of that sequence interacted with the enzyme in a similar manner as the C-terminal tripeptide of CVVM, suggesting that the tripeptide comprises a common structural element for substrate recognition in both tetrapeptide and pentapeptide sequences. Molecular dynamics simulation of CMIIM bound to FTase further shed light on the molecular interactions involved, showing that a putative catalytically competent Zn(II)-thiolate species was able to form. Bioinformatic predictions of tetrapeptide (CaaX-box) reactivity correlated well with the reactivity of pentapeptides obtained from in vivo analysis, reinforcing the importance of the C-terminal tripeptide motif. This analysis provides a structural framework for understanding the reactivity of extended CaaaX-box motifs and a method that may be useful for predicting the reactivity of additional FTase substrates bearing CaaaX-box sequences.

Multiple Intracranial Schwannomas of the Vestibular and Trigeminal Nerves: A Technical Note.

BACKGROUND: A schwannoma is a nerve sheath tumor that is formed by Schwann cells. Vestibular schwannomas are thought to account for the majority of intracranial schwannomas. Nonvestibular schwannomas account for about 10%, about half of which are trigeminal schwannomas. Multiple intracranial schwannomas originating from different cranial nerves are extremely rare. METHODS: We describe the clinical case of a 42-year-old female patient with vestibular schwannoma and multiple trigeminal schwannomas. RESULTS: That case shows how multiple trigeminal schwannomas were identified intraoperatively during elective surgery for vestibular schwannoma removal, most of which were resected. No new neurological deficits were observed in the patient. CONCLUSIONS: The presence of multiple intracranial schwannomas is extremely rare in neurosurgical practice and can change the intraoperative strategy and the course of the surgery.