Killer lymphocytes use granulysin, perforin and granzymes to kill intracellular parasites

Protozoan infections are a serious global health problem1, 2. Natural killer (NK) cells and cytolytic T lymphocytes (CTLs) eliminate pathogen-infected cells by releasing cytolytic granule contents—granzyme (Gzm) proteases and the pore-forming perforin (PFN)—into the infected cell3. However, these cytotoxic molecules do not kill intracellular parasites. CD8+ CTLs protect against parasite infections in mice primarily by secreting interferon (IFN)-γ4, 5, 6, 7, 8, 9, 10. However, human, but not rodent, cytotoxic granules contain the antimicrobial peptide granulysin (GNLY), which selectively destroys cholesterol-poor microbial membranes11, 12, 13, 14, and GNLY, PFN and Gzms rapidly kill intracellular bacteria15. Here we show that GNLY delivers Gzms into three protozoan parasites (Trypanosoma cruzi, Toxoplasma gondii and Leishmania major), in which the Gzms generate superoxide and inactivate oxidative defense enzymes to kill the parasite. PFN delivers GNLY and Gzms into infected cells, and GNLY then delivers Gzms to the intracellular parasites. Killer cell–mediated parasite death, which we term 'microbe-programmed cell death' or 'microptosis', is caspase independent but resembles mammalian apoptosis, causing mitochondrial swelling, transmembrane potential dissipation, membrane blebbing, phosphatidylserine exposure, DNA damage and chromatin condensation. GNLY-transgenic mice are protected against infection by T. cruzi and T. gondii, and survive infections that are lethal to wild-type mice. Thus, GNLY-, PFN- and Gzm-mediated elimination of intracellular protozoan parasites is an unappreciated immune defense mechanism

<i>Caenorhabditis elegans </i>BUB-3 and SAN-1/MAD3 Spindle Assembly Checkpoint Components Are Required for Genome Stability in Response to Treatment with Ionizing Radiation

Relatively little is known about the cross-talk between the spindle assembly checkpoint and the DNA damage response, especially in multicellular organisms. We performed a Caenorhabditis elegans forward genetic screen to uncover new genes involved in the repair of DNA damage induced by ionizing radiation. We isolated a mutation, gt2000, which confers hypersensitivity to ionizing radiation and showed that gt2000 introduces a premature stop in bub-3. BUB-3 is a key component of the spindle assembly checkpoint. We provide evidence that BUB-3 acts during development and in the germline; irradiated bub-3(gt2000) larvae are developmentally retarded and form abnormal vulvae. Moreover, bub-3(gt2000) embryos sired from irradiated worms show increased levels of lethality. Both bub-3 and san-1 (the C. elegans homolog of MAD3) deletion alleles confer hypersensitivity to ionizing radiation, consistent with the notion that the spindle assembly checkpoint pathway is required for the DNA damage response. bub-3(gt2000) is moderately sensitive to the cross-linking drug cisplatin but not to ultraviolet light or methyl methanesulfonate. This is consistent with a role in dealing with DNA double-strand breaks and not with base damage. Double mutant analysis revealed that bub-3 does not act within any of the three major pathways involved in the repair of double-strand breaks. Finally, the cdc-20 gain-of-function mutant cdc-20/fzy-1(av15), which is refractory to the cell cycle delay conferred by the spindle checkpoint, showed phenotypes similar to bub-3 and san-1 mutants. We speculate that BUB-3 is involved in the DNA damage response through regulation of cell cycle timing

Heterochromatin is refractory to γ-H2AX modification in yeast and mammals

Double-strand break (DSB) damage in yeast and mammalian cells induces the rapid ATM (ataxia telangiectasia mutated)/ATR (ataxia telangiectasia and Rad3 related)-dependent phosphorylation of histone H2AX (γ-H2AX). In budding yeast, a single endonuclease-induced DSB triggers γ-H2AX modification of 50 kb on either side of the DSB. The extent of γ-H2AX spreading does not depend on the chromosomal sequences. DNA resection after DSB formation causes the slow, progressive loss of γ-H2AX from single-stranded DNA and, after several hours, the Mec1 (ATR)-dependent spreading of γ-H2AX to more distant regions. Heterochromatic sequences are only weakly modified upon insertion of a 3-kb silent HMR locus into a γ-H2AX–covered region. The presence of heterochromatin does not stop the phosphorylation of chromatin more distant from the DSB. In mouse embryo fibroblasts, γ-H2AX distribution shows that γ-H2AX foci increase in size as chromatin becomes more accessible. In yeast, we see a high level of constitutive γ-H2AX in telomere regions in the absence of any exogenous DNA damage, suggesting that yeast chromosome ends are transiently detected as DSBs

Real-world impact of fremanezumab on migraine symptoms and resource utilization in the United States

BACKGROUND: Fremanezumab, a fully humanized monoclonal antibody (IgG2Δa) that selectively targets calcitonin gene-related peptide (CGRP), is approved for migraine prevention in adults. Real-world data on the effectiveness of fremanezumab are limited. This retrospective, observational cohort study assessed patient-reported migraine symptoms, health care resource utilization (HCRU), and direct medical costs before and after fremanezumab treatment initiation. METHODS: Data were extracted from September 2018 through June 2020 from the Midwest component of EMRClaims+®, an integrated health services database containing \u3e 20 million medical records from national commercial insurance claims, Medicare claims, and regional electronic medical records. Patients included in the cohort analysis were aged ≥ 18 years and were administered fremanezumab, with enrollment or treatment history for ≥ 6 months prior (pre-index) to initiating fremanezumab (index date) and ≥ 1 month after the index date (post-index), and without pregnancy or pregnancy-related encounters during the study period. Patient-reported headache frequency, migraine pain intensity (MPI), composite migraine symptoms, and HCRU were assessed pre-index and ≥ 1 month after fremanezumab initiation. Wilcoxon signed-rank tests were used to compare means of migraine symptoms and outcomes and HCRU before and after fremanezumab initiation. RESULTS: Overall, 172 patients were eligible for analysis. Of patients who self-reported (n = 129), 83.7% reported improvement in headache frequency or symptoms after fremanezumab treatment. Specifically, headache frequency decreased by 63% after fremanezumab initiation: mean (standard deviation) headache frequency was 22.24 (9.29) days per month pre-index versus 8.24 (7.42) days per month post-index (P \u3c 0.0001). Mean MPI also decreased by 18% after fremanezumab initiation: MPI was 5.47 (3.19) pre-index versus 4.51 (3.34) post-index (P = 0.014). Mean emergency room (ER) visits per month decreased from 0.72 to 0.54 (P = 0.003), and mean outpatient visits per month decreased from 1.04 to 0.81 (P \u3c 0.001). Mean hospitalizations per month decreased, but the results did not reach statistical significance (P = 0.095). Hospitalization and ER costs decreased, while outpatient costs increased, from pre-index to post-index, but differences were not statistically significant (P ≥ 0.232). CONCLUSIONS: Significant reductions in headache frequency, MPI, and HCRU were observed after fremanezumab initiation in patients with migraine in a US real-world setting

Clinical and Economic Evaluation of Fluticasone Furoate/Umeclidinium/Vilanterol Versus Tiotropium/Olodaterol Therapy in Maintenance Treatment&ndash;Naive Patients with COPD in the US

Asif Shaikh,1 John Ritz,2 Julian Casciano,3 Swetha R Palli,1 Brendan Clark,1 Zenobia Dotiwala,3 Jennifer K Quint4 1Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, CT, USA; 2Syneos Health-Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, CT, USA; 3eMAX Health, Delray Beach, NY, USA; 4National Heart and Lung Institute, Imperial College London, London, UKCorrespondence: Brendan Clark, Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, CT, 06877, USA, Tel +1 203 317 9644, Email [email protected]: Long-acting bronchodilator (LABD) therapy is recommended for maintenance treatment in most patients with chronic obstructive pulmonary disease (COPD). However, triple therapy (TT; dual LABDs + inhaled corticosteroid [ICS]) is often used as first-line maintenance treatment. The benefits of TT versus dual LABDs as first-line treatments are unknown, necessitating an evaluation of its effectiveness and costs versus non-ICS alternatives.Patients and Methods: This retrospective study assessed administrative claims of maintenance treatment–naive patients in the United States with COPD aged ≥ 40 years initiating single-inhaler fluticasone furoate+umeclidinium+vilanterol (FF+UMEC+VI) or tiotropium+olodaterol (TIO+OLO). Patients were propensity score–matched (1:1) and followed for up to 12 months. The primary outcome was time to first COPD exacerbation. Secondary outcomes included time to first pneumonia diagnosis, pneumonia-related hospitalization, healthcare resource utilization (HCRU), and costs. COPD exacerbation and pneumonia risk were assessed using Cox proportional hazards regression.Results: A total of 5,121 and 3,996 patients met the eligibility criteria for the FF+UMEC+VI and TIO+OLO groups, respectively. Outcomes were assessed among 2,951 matched pairs. The risk of moderate or severe COPD exacerbation was not significantly different between FF+UMEC+VI and TIO+OLO groups (hazard ratio [HR] [95% confidence interval {CI}]: 1.13 [0.99– 1.29]; P=0.064). The risks of pneumonia (HR [95% CI]: 1.04 [0.85– 1.27]; P=0.723) and pneumonia-related hospitalization (HR [95% CI]: 1.18 [0.78– 1.79]; P=0.429) were also not significantly different between the groups. There were no significant differences in HCRU events or all-cause costs; however, FF+UMEC+VI initiators incurred greater COPD- and/or pneumonia-related pharmacy costs than TIO+OLO initiators (FF+UMEC+VI: &dollar;2,934 [&dollar;2,827–&dollar;3,041], TIO+OLO: &dollar;1,994 [&dollar;1,915–&dollar;2,073]; P< 0.001).Conclusion: In maintenance treatment–naive patients, FF+UMEC+VI offered no reduction in COPD exacerbation risk over TIO+OLO and resulted in higher pharmacy costs related to COPD and/or pneumonia treatment. These results support treatment recommendations for LAMA+LABA as initial maintenance therapy.Trial Registration: ClinicalTrials.gov identifier - NCT05169424.Plain Language Summary: Chronic obstructive pulmonary disease (COPD) is a disease affecting the lungs, which causes symptoms such as shortness of breath, cough, and phlegm. The goal of COPD management is to control the symptoms and reduce the risk of flare-ups (exacerbations). COPD maintenance treatments include medications called inhaled corticosteroids (ICS) that reduce airway inflammation and bronchodilators that either prevent the closing of airways (eg, long-acting muscarinic antagonists [LAMAs]), or keep them open longer (eg, long-acting beta2-agonists [LABAs]). National and international guidelines recommend triple therapy (ICS+LAMA+LABA) for symptomatic patients who continue to have frequent exacerbations despite LAMA+LABA dual therapy. However, the use of triple therapy as the first treatment choice is common in everyday clinical practice, even in patients who have not received any long-acting bronchodilators in the past (maintenance treatment–naive patients). Therefore, our study compared the clinical and economic outcomes in maintenance treatment–naive patients who were given single-inhaler triple therapy (LAMA+LABA+ICS) with those who were given dual therapy (LAMA+LABA). In our study, the risk of COPD flare-up, pneumonia, and hospitalization due to pneumonia was not different between patients who received triple and dual therapy, indicating no significant benefit of triple therapy over dual therapy. Additionally, triple therapy resulted in higher pharmacy costs. We conclude that for patients with COPD starting maintenance treatment, dual therapy was not only as effective as triple therapy in managing COPD but also had economic benefits.Keywords: dual bronchodilator therapy, exacerbation risk, health outcomes, maintenance treatment–naive, treatment initiation, triple therap

Burden of asthma with elevated blood eosinophil levels

BACKGROUND: Asthma is a common chronic condition with an economic burden of almost $56 billion annually in the US. Biologic markers like blood eosinophils, that help predict the risk of exacerbation could help guide more optimal treatment plans and reduce cost. The purpose of this study was to determine whether healthcare resource use and expenditures vary by eosinophil level among patients with asthma. METHODS: Patients with a diagnosis of asthma defined by ICD-9-CM code 493.xx between January 2004 and July 2011 were extracted from EMRClaims + database (eMAX Health, White Plains NY). Patients were classified as mild, moderate, or severe by medication use following diagnosis, based on recommendations of National Institutes of Health Expert Panel Report 3. Patients were classified as those with elevated eosinophils (≥400 cells/μL) and normal eosinophil level (<400 cells/μL). Patients were followed for resource use, defined as hospitalizations, ER visits and outpatient visit and associated costs were calculated to assess whether an economic difference exists between eosinophil groups. Non-parametric tests were used to compare resource use and associated cost between elevated and normal eosinophil groups. Multivariate modeling was performed to assess the contribution of eosinophil level on the likelihood of study outcomes among patients with severe asthma. RESULTS: Among the 2,164 patients meeting eligibility criteria, 1,144 had severity designations. Of these, 179(16$1,091, p = 0.011). Logistic regressions showed that elevated eosinophil level was associated with 5.14 times increased odds of all cause admissions (95 % CI:1.76–14.99, p = 0.003) and 4.07 times increased odds of asthma related admissions (95 % CI: 1.26–13.12, p = 0.019). CONCLUSION: Eosinophil elevation was associated with greater healthcare resource use in patients with asthma

Cdc28/Cdk1 positively and negatively affects genome stability in S. cerevisiae

We studied the function of the cyclin-dependent kinase Cdc28 (Cdk1) in the DNA damage response and maintenance of genome stability using Saccharomyces cerevisiae. Reduced Cdc28 activity sensitizes cells to chronic DNA damage, but Cdc28 is not required for cell viability upon acute exposure to DNA-damaging agents. Cdc28 is also not required for activation of the DNA damage and replication checkpoints. Chemical–genetic analysis reveals that CDC28 functions in an extensive network of pathways involved in maintenance of genome stability, including homologous recombination, sister chromatid cohesion, the spindle checkpoint, postreplication repair, and telomere maintenance. In addition, Cdc28 and Mre11 appear to cooperate to prevent mitotic catastrophe after DNA replication arrest. We show that reduced Cdc28 activity results in suppression of gross chromosomal rearrangements (GCRs), indicating that Cdc28 is required for formation or recovery of GCRs. Thus, we conclude that Cdc28 functions in a genetic network that supports cell viability during DNA damage while promoting the formation of GCRs

Sgs1 and Exo1 Redundantly Inhibit Break-Induced Replication and De Novo Telomere Addition at Broken Chromosome Ends

In budding yeast, an HO endonuclease-inducible double-strand break (DSB) is efficiently repaired by several homologous recombination (HR) pathways. In contrast to gene conversion (GC), where both ends of the DSB can recombine with the same template, break-induced replication (BIR) occurs when only the centromere-proximal end of the DSB can locate homologous sequences. Whereas GC results in a small patch of new DNA synthesis, BIR leads to a nonreciprocal translocation. The requirements for completing BIR are significantly different from those of GC, but both processes require 5′ to 3′ resection of DSB ends to create single-stranded DNA that leads to formation of a Rad51 filament required to initiate HR. Resection proceeds by two pathways dependent on Exo1 or the BLM homolog, Sgs1. We report that Exo1 and Sgs1 each inhibit BIR but have little effect on GC, while overexpression of either protein severely inhibits BIR. In contrast, overexpression of Rad51 markedly increases the efficiency of BIR, again with little effect on GC. In sgs1Δ exo1Δ strains, where there is little 5′ to 3′ resection, the level of BIR is not different from either single mutant; surprisingly, there is a two-fold increase in cell viability after HO induction whereby 40% of all cells survive by formation of a new telomere within a few kb of the site of DNA cleavage. De novo telomere addition is rare in wild-type, sgs1Δ, or exo1Δ cells. In sgs1Δ exo1Δ, repair by GC is severely inhibited, but cell viaiblity remains high because of new telomere formation. These data suggest that the extensive 5′ to 3′ resection that occurs before the initiation of new DNA synthesis in BIR may prevent efficient maintenance of a Rad51 filament near the DSB end. The severe constraint on 5′ to 3′ resection, which also abrogates activation of the Mec1-dependent DNA damage checkpoint, permits an unprecedented level of new telomere addition

Rpb1 Sumoylation in Response to UV Radiation or Transcriptional Impairment in Yeast

Covalent modifications of proteins by ubiquitin and the Small Ubiquitin-like MOdifier (SUMO) have been revealed to be involved in a plethora of cellular processes, including transcription, DNA repair and DNA damage responses. It has been well known that in response to DNA damage that blocks transcription elongation, Rpb1, the largest subunit of RNA polymerase II (Pol II), is ubiquitylated and subsequently degraded in mammalian and yeast cells. However, it is still an enigma regarding how Pol II responds to damaged DNA and conveys signal(s) for DNA damage-related cellular processes. We found that Rpb1 is also sumoylated in yeast cells upon UV radiation or impairment of transcription elongation, and this modification is independent of DNA damage checkpoint activation. Ubc9, an E2 SUMO conjugase, and Siz1, an E3 SUMO ligase, play important roles in Rpb1 sumoylation. K1487, which is located in the acidic linker region between the C-terminal domain and the globular domain of Rpb1, is the major sumoylation site. Rpb1 sumoylation is not affected by its ubiquitylation, and vice versa, indicating that the two processes do not crosstalk. Abolishment of Rpb1 sumoylation at K1487 does not affect transcription elongation or transcription coupled repair (TCR) of UV-induced DNA damage. However, deficiency in TCR enhances UV-induced Rpb1 sumoylation, presumably due to the persistence of transcription-blocking DNA lesions in the transcribed strand of a gene. Remarkably, abolishment of Rpb1 sumoylation at K1487 causes enhanced and prolonged UV-induced phosphorylation of Rad53, especially in TCR-deficient cells, suggesting that the sumoylation plays a role in restraining the DNA damage checkpoint response caused by transcription-blocking lesions. Our results demonstrate a novel covalent modification of Rpb1 in response to UV induced DNA damage or transcriptional impairment, and unravel an important link between the modification and the DNA damage checkpoint response