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Molecular dynamics simulations have been remarkably effective for observing and analyzing structures and dynamics of proteins, with longer trajectories being computed every day. Still, often, relevant time scales are not observed. Adequately analyzing the generated trajectories can highlight the interesting areas within a protein such as mutation sites or allosteric hotspots, which might foreshadow dynamics untouched by the simulations. We employ a physics-based protein network and propose that such a network can adequately analyze the protein dynamics. The analysis is conducted on simulations of cathepsin G and neutrophil elastase, which are remarkably similar but with different specificities. However, a single mutation in cathepsin G recovers the specificity of neutrophil elastase. The physics-based network built on the interactions between residues instead of the distances can pinpoint the active triad in the proteins studied. Overall, the network seems to capture the structural behavior better than purely distance-based networks.

Psoriasis, an inflammatory disease, is largely mediated by T-helper 17 cytokines. We have previously identified the immune system-released activating agent (Israa) as a novel gene that connects the nervous and immune systems. This research aims to investigate the role of the Israa gene in psoriasis in vivo using the imiquimod-induced psoriasis model. We established the model in C57BL/6 wildtype mice, which were then treated with 200 pg/mouse, 400 pg/mouse, or 800 pg/mouse of recombinant ISRAA compared to methotrexate. Subsequently, we also induced psoriasis in Israa-knockout mice to confirm the effect of Israa. Results consistently showed improvement in psoriasis in all groups receiving recombinant ISRAA. The 200 pg/mouse dose eliminated the disease, reduced the cutaneous release of IL-17 to one-third and TNF-α to one-sixth, increased IL-10 release to over 500 pg, completely resolved parakeratosis, decreased epidermal thickness to one-half, and reduced the expression of CD4 and neutrophil elastase in the skin (all p < 0.05). Israa-knockout mice exhibited less severe psoriasis in all scoring, biochemical, and histological parameters compared to wild-type mice (p < 0.05). This study highlights Israa as a crucial molecule in psoriasis and confirms its immunomodulatory role in inflammatory diseases., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Severe congenital neutropenia (SCN) comprises a diverse range of rare hematological disorders characterized by recurrent, often life-threatening infections that manifest within the first months of life. Mutations in the ELANE gene are the most prevalent cause of SCN. While over 230 mutations in ELANE have been documented, including substitutions, frameshifts, nonsense mutations, and splice site alterations, the occurrence of deep intronic mutations has not been previously reported. Herein, we present the case of a young girl who exhibited recurrent fever, respiratory infections, skin abscesses, and gingivitis shortly after birth. Laboratory analysis revealed markedly diminished neutrophil levels alongside elevated monocyte and eosinophil counts. Bone marrow examination disclosed a halt in myelopoiesis maturation. ELANE gene full-length sequencing identified a novel de novo deep intron mutation in ELANE (c.598 + 79G > T), subsequently confirmed by Sanger sequencing. cDNA sequencing of the patient demonstrated aberrant gene splicing. Utilizing a mini-gene splicing assay for ELANE intronic variants, we identified a mutant ELANE allele (c.597 + 1&#95;597 + 83ins) leading to the creation of a premature termination codon (p.Gly200ValfsTer40). Confocal microscopy revealed heightened expression of myeloperoxidase and neutrophil elastase in the patient, suggesting a potential role for the unfolded protein response in the pathogenesis of the deep intron ELANE mutation. In summary, our findings illustrate the first reported instance of de novo deep intron ELANE mutations associated with SCN, underscoring the importance of exploring deep intronic regions in SCN patients lacking identifiable disease-causing gene mutations., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Severe congenital neutropenia is an inherited bone marrow failure disorder characterized by profoundly low neutrophil counts and promyelocytic maturation arrest in bone marrow. Severe congenital neutropenia is most often caused by heterozygous ELANE mutations. In vitro and mouse xenograft studies using CRISPR/Cas9 have shown that introduction of frameshift/nonsense mutations in mutant ELANE may restore neutrophil counts, providing a model for gene therapy. Here, we present 2 children with inherited nonsense mutations in ELANE analogous to those proposed for gene therapy. Their normal peripheral blood neutrophil counts provide support for this approach through human "experiments of nature.", Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Human interleukin-33 (IL-33) is a 270 amino acid protein that belongs to the IL-1 cytokine family and plays an important role in various inflammatory disorders. Neutrophil proteases (Cathepsin G and Elastase) and mast cell proteases (tryptase and chymase) regulate the activity of IL-33 by processing full-length IL-33 into its mature form. There is little evidence on the role of these mature forms of IL-33 in retinal endothelial cell signaling and pathological retinal angiogenesis. Here, we cloned, expressed, and purified the various mature forms of human IL-33 and then evaluated the effects of IL-33 95-270 , IL-33 99-270 , IL-33 109-270 , and IL-33 112-270 on angiogenesis in human retinal microvascular endothelial cells (HRMVECs). We observed that IL-33 95-270 , IL-33 99-270 , IL-33 109-270 , and IL-33 112-270 significantly induced HRMVEC migration, tube formation and sprouting angiogenesis. However, only IL-33 99-270 could induce HRMVEC proliferation. We used a murine model of oxygen-induced retinopathy (OIR) to assess the role of these mature forms of IL-33 in pathological retinal neovascularization. Our 3'-mRNA sequencing and signaling studies indicated that IL-33 99-270 and IL-33 109-270 were more potent at inducing endothelial cell activation and angiogenesis than the other mature forms. We found that genetic deletion of IL-33 significantly reduced OIR-induced retinal neovascularization in the mouse retina and that intraperitoneal administration of mature forms of IL-33, mainly IL-33 99-270 and IL-33 109-270 , significantly restored ischemia-induced angiogenic sprouting and tuft formation in the hypoxic retinas of IL-33 -/- mice. Thus, our study results suggest that blockade or inhibition of IL-33 cleavage by neutrophil proteases could help mitigate pathological angiogenesis in proliferative retinopathies., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Severe congenital neutropenia (CN) is an inherited pre-leukemia bone marrow failure syndrome commonly caused by autosomal-dominant ELANE mutations (ELANE-CN). ELANE-CN patients are treated with daily injections of recombinant human granulocyte colony-stimulating factor (rhG-CSF). However, some patients do not respond to rhG-CSF, and approximately 15% of ELANE-CN patients develop myelodysplasia or acute myeloid leukemia. Here, we report the development of a curative therapy for ELANE-CN through inhibition of ELANE mRNA expression by introducing two single-strand DNA breaks at the opposing DNA strands of the ELANE promoter TATA box using CRISPR-Cas9D10A nickases-termed MILESTONE. This editing effectively restored defective neutrophil differentiation of ELANE-CN CD34 + hematopoietic stem and progenitor cells (HSPCs) in vitro and in vivo, without affecting the functions of the edited neutrophils. CRISPResso analysis of the edited ELANE-CN CD34 + HSPCs revealed on-target efficiencies of over 90%. Simultaneously, GUIDE-seq, CAST-Seq, and rhAmpSeq indicated a safe off-target profile with no off-target sites or chromosomal translocations. Taken together, ex vivo gene editing of ELANE-CN HSPCs using MILESTONE in the setting of autologous stem cell transplantation could be a universal, safe, and efficient gene therapy approach for ELANE-CN patients., Competing Interests: Declaration of interests M.N., P.M., and J.S. have filed a patent on the invention described in this study. T.C. is an advisor to Cimeio Therapeutics and Excision BioTherapeutics and holds a patent on CAST-Seq., (Copyright © 2024 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for causing coronavirus disease 2019 (COVID-19). The development and severity of this infectious disease is influenced by a combination of environmental and genetic factors. Angiotensin-converting enzyme 2 (ACE2) facilitates SARS-CoV-2 entry into human cells, with transmembrane serine protease 2 (TMPRSS2) playing a crucial role in S protein priming. Other proteases, such as cathepsin L and elastase, neutrophil-expressed (ELANE), have the capability to prime the S protein and contribute to SARS-CoV-2 infection. ELANE variants have not been previously examined in COVID-19 patients. We aimed to assess the association of single nucleotide variants (SNVs) within ELANE with COVID-19 and biochemical markers. The study included 319 SARS-CoV-2-infected patients and 288 controls. Genotyping of ELANE rs17216663C/T (Pro257Leu), rs17223045C/T (As1n30Asn), and rs3761007G/A was conducted using a 5'-nuclease allelic discrimination assay (TaqMan assay). Our findings indicate that ELANE rs17223045C/T (C vs T: odds ratio [OR] 0.08, P = 0.005, and CC vs CT: OR 0.08, P = 0.005) and rs3761007G/A (G vs A: OR 0.38, P = 0.009, and GG vs GA: OR 0.40, P = 0.008) confer protection against COVID-19. However, these variants were not associated with biochemical markers. In conclusion, our data suggests that ELANE rs17223045C/T and rs3761007G/A SNVs may play a protective role against COVID-19.

Mutations in the ELANE gene, encoding the neutrophil elastase (NE) protein, are responsible for most cyclic neutropenia (CyN) cases and approximately 25% of congenital neutropenia (CN) cases. In CN and in CyN, a median of 2.8% of CD34+ cells were early CD49f+ hematopoietic stem cells (eHSC) that did not express ELANE and thus escape from the unfolded protein response (UPR) caused by mutated NE. In CyN, the CD49f+ cells respond to granulocyte colony-stimulating factor (G-CSF) with a significant upregulation of the hematopoietic stem cell-specific transcription factors, C/EBPα, MLL1, HOXA9, MEIS1, and HLF during the ascending arm of the cycle, resulting in the differentiation of myeloid cells to mature neutrophils at the cycle peak. However, NE protein released by neutrophils at the cycle's peak caused a negative feedback loop on granulopoiesis through the proteolytic digestion of G-CSF. In contrast, in CN patients, CD49f+ cells failed to express mRNA levels of HSC-specific transcription factors mentioned above. Rescue of C/EBPα expression in CN restored granulopoiesis.

Metastatic disease remains the leading cause of death due to cancer, yet the mechanism(s) of metastasis and its timely detection remain to be elucidated. Neutrophil elastase (NE), a serine protease secreted by neutrophils, is a crucial mediator of chronic inflammation and tumor progression. In this study, we used the PyMT model (NE+/+ and NE-/-) of breast cancer to interrogate the tumor-intrinsic and -extrinsic mechanisms by which NE can promote metastasis. Our results showed that genetic ablation of NE significantly reduced lung metastasis and improved metastasis-free survival. RNA-sequencing analysis of primary tumors indicated differential regulation of tumor-intrinsic actin cytoskeleton signaling pathways by NE. These NE-regulated pathways are critical for cell-to-cell contact and motility and consistent with the delay in metastasis in NE-/- mice. To evaluate whether pharmacologic inhibition of NE inhibited pulmonary metastasis and phenotypically mimicked PyMT NE-/- mice, we utilized AZD9668, a clinically available and specific NE inhibitor. We found AZD9668 treated PyMT-NE+/+ mice showed significantly reduced lung metastases, improved recurrence-free, metastasis-free and overall survival, and their tumors showed similar molecular alterations as those observed in PyMT-NE-/- tumors. Finally, we identified a NE-specific signature that predicts recurrence and metastasis in patients with breast cancer. Collectively, our studies suggest that genetic ablation and pharmacologic inhibition of NE reduces metastasis and extends survival of mouse models of breast cancer, providing rationale to examine NE inhibitors as a treatment strategy for the clinical management of patients with metastatic breast cancer., (©2023 American Association for Cancer Research.)

Neutropenia is a hematological condition characterized by a decrease in absolute neutrophil count (ANC) in peripheral blood, typically classified in adults as mild (1-1.5 × 10 9 /L), moderate (0.5-1 × 10 9 /L), or severe (< 0.5 × 10 9 /L). It can be categorized into two types: congenital and acquired. Congenital severe chronic neutropenia (SCN) arises from mutations in various genes, with different inheritance patterns, including autosomal recessive, autosomal dominant, and X-linked forms, often linked to mitochondrial diseases. The most common genetic cause is alterations in the ELANE gene. Some cases exist as non-syndromic neutropenia within the SCN spectrum, where genetic origins remain unidentified. The clinical consequences of congenital neutropenia depend on granulocyte levels and dysfunction. Infants with this condition often experience recurrent bacterial infections, with approximately half facing severe infections within their first six months of life. These infections commonly affect the respiratory system, digestive tract, and skin, resulting in symptoms like fever, abscesses, and even sepsis. The severity of these symptoms varies, and the specific organs and systems affected depend on the genetic defect. Congenital neutropenia elevates the risk of developing acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS), particularly with certain genetic variants. SCN patients may acquire CSF3R and RUNX1 mutations, which can predict the development of leukemia. It is important to note that high-dose granulocyte colony-stimulating factor (G-CSF) treatment may have the potential to promote leukemogenesis. Treatment for neutropenia involves antibiotics, drugs that boost neutrophil production, or bone marrow transplants. Immediate treatment is essential due to the heightened risk of severe infections. In severe congenital or cyclic neutropenia (CyN), the primary therapy is G-CSF, often combined with antibiotics. The G-CSF dosage is gradually increased to normalize neutrophil counts. Hematopoietic stem cell transplants are considered for non-responders or those at risk of AML/MDS. In cases of WHIM syndrome, CXCR4 inhibitors can be effective. Future treatments may involve gene editing and the use of the diabetes drug empagliflozin to alleviate neutropenia symptoms., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Neutrophil elastase (NE), a major inflammatory mediator in chronic obstructive pulmonary disease (COPD) airways, impairs macrophage function, contributing to persistence of airway inflammation. We hypothesized that NE activates a novel mechanism of macrophage-induced inflammation: release of macrophage extracellular traps (METs). The METs are composed of extracellular DNA decorated with granule proteinases and oxidants and may trigger persistent airway inflammation in COPD. To test the hypothesis, human blood monocytes were isolated from whole blood of subjects with COPD recruited following informed written consent. Patient demographics and clinical data were collected. Cells were cultured in media with GM-CSF to differentiate into blood monocyte derived macrophages (BMDMs). The BMDMs were treated with FITC-NE and unlabeled NE to determine intracellular localization by confocal microscopy and intracellular proteinase activity by DQ-Elastin assay. After NE exposure, released extracellular traps were quantified by abundance of extracellular DNA in conditioned media using the Pico Green assay. BMDM cell lysates were analyzed by Western analysis for proteolytic degradation of histone H3 or H4 or upregulation of peptidyl arginine deiminase (PAD) 2 and 4, two potential mechanisms to mediate extracellular trap DNA release. We observed that NE was taken up by COPD BMDM, localized to the cytosol and nucleus, and retained proteinase activity in the cell. NE induced MET release at doses as low as 50 nM. NE treatment caused histone H3 clipping but no effect on histone H4 nor PAD 2 or 4 abundance or activity. In summary, NE activated COPD MET release by clipping histone H3, a prerequisite for chromatin decondensation., (© 2023 The Authors. Clinical and Translational Science published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Background: Congenital neutropenia is a rare disease. Recurrent infections since young age are the presentation. The most common mutation causing severe congenital neutropenia (SCN) and cyclic neutropenia (CyN) is the ELANE gene. The objectives of this study were to screen the three common genetic mutations of ELANE, HAX1 and GFI1 in children with chronic neutropenia and to describe the clinical characteristics of children who had the mutations., Methods: Infants having ANC < 1,000/cu mm or children aged > 1 year having ANC < 1,500/cu mm at least 3 times in 3 months were enrolled in the study. Patients who had acquired neutropenia due to infection, immune deficiency, or drugs were excluded. The ELANE gene was first studied; and if mutations were not identified, the HAX1 and GFI1 genes were further examined., Results: A total of 60 patients were enrolled in the study. The median (range) age, ratio of female to male, ANC, and last follow-up age were 9.2 (0.5-45.2) months, 1:1.2, 248 (0-1,101) /cu mm, and 19.9 (3.5-202.3) months, respectively. Infections were noted in 67.3% of all patients. ELANE gene mutation was found in only four patients (6.7%), and the rest (56 patients) showed no mutations in the HAX1 and GFI1 genes. In patients without mutations, 66.0% had normal ANC during the follow-up, with a median (range) age for normal ANC of 19.8 (4.0-60.0) months. Two novel mutations p. Ala79del (c.234&#95;236del) and p. Val197GlufsTer18 (c.589&#95;590insAGGCCGGC) were identified, and they respectively cause SCN and CyN. Patients with the two novel mutations presented with several episodes of infection, including pneumonia, sepsis, abscess, otitis media, and gum infection., Conclusion: The genetic screening for ELANE, HAX1, and GFI1 gene mutations in 60 patients with chronic neutropenia could identify four patients (6.7%) with ELANE gene mutation and two novel mutations, p. Ala79del in exon 3 and p. Val197GlufsTer18 in exon 4 causing SCN; and CyN, respectively., (© 2023. The Author(s).)

Background: Thoracic aortic dissection (TAD) is a life-threatening aortic disease without effective medical treatment. Increasing evidence has suggested a role for NE (neutrophil elastase) in vascular diseases. In this study, we aimed at investigating a causal role for NE in TAD and exploring the molecular mechanisms involved., Methods: β-aminopropionitrile monofumarate was administrated in mice to induce TAD. NE deficiency mice, pharmacological inhibitor GW311616A, and adeno-associated virus-2-mediated in vivo gene transfer were applied to explore a causal role for NE and associated target gene in TAD formation. Multiple functional assays and biochemical analyses were conducted to unravel the underlying cellular and molecular mechanisms of NE in TAD., Results: NE aortic gene expression and plasma activity was significantly increased during β-aminopropionitrile monofumarate-induced TAD and in patients with acute TAD. NE deficiency prevents β-aminopropionitrile monofumarate-induced TAD onset/development, and GW311616A administration ameliorated TAD formation/progression. Decreased levels of neutrophil extracellular traps, inflammatory cells, and MMP (matrix metalloproteinase)-2/9 were observed in NE-deficient mice. TBL1x (F-box-like/WD repeat-containing protein TBL1x) has been identified as a novel substrate and functional downstream target of NE in TAD. Loss-of-function studies revealed that NE mediated inflammatory cell transendothelial migration by modulating TBL1x-LTA4H (leukotriene A4 hydrolase) signaling and that NE regulated smooth muscle cell phenotype modulation under TAD pathological condition by regulating TBL1x-MECP2 (methyl CpG-binding protein 2) signal axis. Further mechanistic studies showed that TBL1x inhibition decreased the binding of TBL1x and HDAC3 (histone deacetylase 3) to MECP2 and LTA4H gene promoters, respectively. Finally, adeno-associated virus-2-mediated Tbl1x gene knockdown in aortic smooth muscle cells confirmed a regulatory role for TBL1x in NE-mediated TAD formation., Conclusions: We unravel a critical role of NE and its target TBL1x in regulating inflammatory cell migration and smooth muscle cell phenotype modulation in the context of TAD. Our findings suggest that the NE-TBL1x signal axis represents a valuable therapeutic for treating high-risk TAD patients., Competing Interests: Disclosures None.

The most common causes of congenital neutropenia are mutations in the ELANE (Elastase, Neutrophil Expressed) gene (19p13.3), mostly in exon 5 and the distal portion of exon 4, which result in different clinical phenotypes of neutropenia. Here, we report two pathogenic mutations in ELANE , namely, c.607G>C (p.Gly203Arg) and a novel variant c.416C>G (p.Pro139Arg), found in two Mexican families ascertained via patients with congenital neutropenia who responded positively to the granulocyte colony-stimulating factor (G-CSF) treatment. These findings highlight the usefulness of identifying variants in patients with inborn errors of immunity for early clinical management and the need to rule out mosaicism in noncarrier parents with more than one case in the family., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Núñez-Núñez, Lona-Reyes, López-Barragán, Cruz-Osorio, Gutiérrez-Zepeda, Quintero-Ramos and Becerra-Loaiza.)

Exploring biomarkers interrelated the tumor immune microenvironment (TIME) provides novel ideas for predicting the prognosis of gastric cancer (GC) and developing new treatment strategies. We analyzed the differential gene expression levels between the high and low StromalScore and ImmuneScore groups. Neutrophil elastase (ELANE) was evaluated as a potential biomarker by conducting intersection analysis of the protein-protein interaction network and univariate Cox regression analysis. The expression of ELANE was evaluated by immunohistochemistry. Its prognostic value was evaluated using Kaplan-Meier (K-M) survival curves and multivariate Cox regression analysis and its potential biological molecular mechanism was examined by gene set enrichment analysis (GSEA). We applied the CIBERSORT computing method to analyze the relationship between ELANE and tumor immune-infiltrating cells (TIICs). K-M survival curve showed that higher ELANE expression was closely related to shorter overall survival. The Cox regression analysis indicated that the high expression of ELANE was an independent prognostic risk factor in patients with GC. The GSEA revealed that genes in the ELANE high-expression group were involved in the signaling pathways regulating immune response; genes in the ELANE low-expression group were involved in the signaling pathways that regulate metabolism. ELANE might be participate in the change of TIME from immunodominant to metabolically dominant and its expression was closely related to tumor mutation burden and multiple TIICs. ELANE is a potential biomarker for predicting the GC patients' survival and prognosis. It influences the tumor immune cell infiltration in the TIME, and affects the TIME to maintain their immune status., (© 2023. Springer Nature Limited.)

Recombinant human neutrophil elastase (rHNE), a serine protease, was expressed in Pichia pastoris. Glycosylation sites were removed via bioengineering to prevent hyper-glycosylation (a common problem with this system) and the cDNA was codon optimized for translation in Pichia pastoris. The zymogen form of rHNE was secreted as a fusion protein with an N-terminal six histidine tag followed by the heme binding domain of Cytochrome B5 (CytB5) linked to the N-terminus of the rHNE sequence via an enteropeptidase cleavage site. The CytB5 fusion balanced the very basic rHNE (pI = 9.89) to give a colored fusion protein (pI = 6.87), purified via IMAC. Active rHNE was obtained via enteropeptidase cleavage, and purified via cation exchange chromatography, resulting in a single protein band on SDS PAGE (Mr = 25 KDa). Peptide mass fingerprinting analysis confirmed the rHNE amino acid sequence, the absence of glycosylation and the absence of an 8 amino acid C-terminal peptide as opposed to the 20 amino acids usually missing from the C-terminus of native enzyme. The yield of active rHNE was 0.41 mg/L of baffled shaker flask culture medium. Active site titration with alpha-1 antitrypsin, a potent irreversible elastase inhibitor, quantified the concentration of purified active enzyme. The Km of rHNE with methoxy-succinyl-AAPVpNA was identical with that of the native enzyme within the assay's limit of accuracy. This is the first report of full-length rHNE expression at high yields and low cost facilitating further studies on this major human neutrophil enzyme., (Copyright © 2023 Elsevier Inc. All rights reserved.)

An assay for neutrophil-specific antibodies is frequently used in the workup of chronic severe neutropenia and is suggestive of autoimmune, or sporadically alloimmune neutropenia, rather than severe congenital neutropenia (SCN). We analyzed a neutropenia consortium database for the outcomes of antibody testing initiated before receiving genetic diagnosis in Polish SCN cohort. Test results, performed in a single reference laboratory, were available for 14 patients with ELANE-mutated SCN or cyclic neutropenia, and were frequently positive (36%). We note that the trigger for genetic studies in severe neutropenia should not be affected by antibody-positivity and should be clinically driven., (© 2023 Wiley Periodicals LLC.)

Rationale: The Severe congenital neutropenia (SCN) is a rare genetic disease characterized by a deficiency of mature neutrophils in the bone marrow and peripheral blood disorders. After a BALF ACER examination, the patient was found to have a rareMycobacterium abscess infection., Patient Concerns: We report a case of SCN withMycobacterium abscess infection caused by ELANE gene mutation. Conventional antiinfection and granulocyte colony-stimulating factor (G-CSF) did not ameliorate patient's symptoms. The absolute neutrophil count (ANC) most of the time < 0.50 × 109/L., Diagnoses: According to Gene sequencing and other tests, the patient was diagnosed with SCN caused by ELANE gene mutation, severe pneumonia, Mycobacteriosis abscess, nutritional iron deficiency anemia, multiple abscesses of the skin, hypergammaglobuloemia, and thrush., Interventions: Anti-infection agents, abscess incision and drainage, blood transfusion, G-CSF were treated., Outcomes: The fever subsided, the cough disappeared, the anemia improved, and the ANC improved (0.69 × 109/L). Currently, the patient has been followed up in the outpatient clinic for 20months, during which time fever, bone pain, gingivitis and thrush occasionally appeared. The ANC fluctuated between 0.20 and 1.27 × 109/L, suggesting the need for a timely hematopoietic stem cell transplant (HSCT)., Lessons: ELANE gene-related SCN is rare in children, and the possibility of this disease should be considered in children with recurrent severe bacterial infections and a significant reduction in neutrophils in the peripheral blood shortly after birth. In addition to strengthening nursing care and actively preventing and controlling infection, other rare bacterial infections should be considered in clinical practice., Competing Interests: The authors declare that this research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Neutropenia related to ELANE gene mutations predisposes patients to infection and leukemia/myelodysplasia, but little is known about the predisposition to cancer. Among a cohort of 147 patients, we identified four with malignant solid tumors (papillary thyroid cancer, anal squamous cell cancer, papillary renal cell carcinoma, and adrenocortical carcinoma), all aged 25-50 years. Three occurred with cyclic neutropenia, and one occurred with severe chronic neutropenia. Previous radiotherapy was identified as a risk factor in one patient. No genetic predisposition was identified in the three other patients., (© 2022 The Authors. Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

The study analyzed the effect of leukocyte elastase (LE) in 460 semen on sperm quality, and explore the reference interval of normal level of LE in semen. The differences of LE levels between normal semen and few, weak and abnormal semen were analyzed. Referring to domestic standards, the samples were divided into normal group (LE ≤ 250 ng/mL), occult infection (250 < LE ≤ 1000 ng/mL), and infection group (LE > 1000 ng/mL), and the differences in semen quality among the groups were compared. According to European standards, the samples were divided into normal group (≤600 ng/mL) and abnormal group (>600 ng/mL), and the differences in semen quality between the 2 groups were compared. The correlation between LE levels in semen and semen quality were analyzed. The positive rates of LE in the normal semen group and abnormal semen groups were 30.7% versus 34.7%, and there was no significant difference between the two groups (P > .05). When the semen divided into 3 groups, there was no significant difference between the physicochemical parameters, kinetic parameters, movement trajectory parameters, morphological parameters, and sperm DNA fragmentation index (DFI) (P > .05). There were significant differences in sperm morphology and sperm DFI between the two groups at 600 ng/mL (P < .05). Spearman correlation analysis showed that there was no significant difference between the level of LE in semen and physicochemical parameters, sperm kinetic parameters, sperm movement trajectory parameters, sperm morphological parameters, and sperm DFI (P > .05). It is appropriate to use 600 ng/mL as the threshold for the concentration of LE in semen; the correlation between the level of LE and sperm quality is not significant., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Neutropenia congenita grave (SCN) is a rare disease with a genetically and clinically heterogeneous nature, usually diagnosed in childhood, with an elevated risk of infections such as otitis, skin infections, pneumonia, deep abscesses, and septicemia. Patients with SCN also have an increased risk of leukemia, and mutations in the ELANE and the HAX1 genes have been observed in those patients. This study was conducted to genetically screen six Iranian families with SCN who have at least one affected person. In the first step, all exons and intron boundaries of ELANE and HAX1 genes were sequenced in probands. Cases with no pathogenic mutations were tested through whole-exome sequencing (WES). Analysis showed five different variants in ELANE (c.377 C>T), HAX1 (c.130&#95;131 insA), HYOU1 (c.69 G>C and c.2744 G>A) and SHOC2 (c.4 A>G) genes in four families. We found that two out of six families had mutations in ELANE and HAX1 genes. Moreover, we found two novel mutations at the HYOU1 gene that had not previously been reported, as well as a pathogenic mutation at SHOC2 with multiple phenotypes, that will contribute to determining the genetic basis for SCN. Our study revealed that WES could help diagnose SCN, improve the classification of neutropenia, and rule out other immunodeficiencies such as autoimmune neutropenia, primary immunodeficiency diseases, and inherited bone marrow failure syndromes.

Muco-obstructive lung diseases are characterized by airway obstruction and hyperinflation, which can be quantified by imaging. Our aim was to evaluate µCT for longitudinal quantification of muco-obstructive lung disease in β-epithelial Na + channel overexpressing ( Scnn1b -TG) mice and of the effects of neutrophil elastase (NE) knockout on its progression. Lungs from wild-type (WT), NE -/- , Scnn1b -TG, and Scnn1b -TG/NE -/- mice were scanned with 9-µm resolution at 0, 5, 14, and 60 days of age, and airway and parenchymal disease was quantified. Mucus adhesion lesions (MAL) were persistently increased in Scnn1b -TG compared with WT mice from 0 days (20.25 ± 6.50 vs. 9.60 ± 2.07, P < 0.05), and this effect was attenuated in Scnn1b -TG/NE -/- mice (5.33 ± 3.67, P < 0.001). Airway wall area percentage (WA%) was increased in Scnn1b -TG mice compared with WT from 14 days onward (59.2 ± 6.3% vs. 49.8 ± 9.0%, P < 0.001) but was similar in Scnn1b -TG/NE -/- compared with WT at 60 days (46.4 ± 9.2% vs. 45.4 ± 11.5%, P = 0.97). Air proportion (Air%) and mean linear intercept ( L m ) were persistently increased in Scnn1b -TG compared with WT from 5 days on (53.9 ± 4.5% vs. 30.0 ± 5.5% and 78.82 ± 8.44 µm vs. 65.66 ± 4.15 µm, respectively, P < 0.001), whereas in Scnn1b -TG/NE -/- , Air% and L m were similar to WT from birth (27.7 ± 5.5% vs. 27.2 ± 5.9%, P = 0.92 and 61.48 ± 9.20 µm vs. 61.70 ± 6.73 µm, P = 0.93, respectively). Our results suggest that µCT is sensitive to detect the onset and progression of muco-obstructive lung disease and effects of genetic deletion of NE on morphology of airways and lung parenchyma in Scnn1b -TG mice, and that it may serve as a sensitive endpoint for preclinical studies of novel therapeutic interventions for muco-obstructive lung diseases.

Background: Clinical and genetic characteristics of ELANE mutation of a 3-year-old male who had a severe congenital neutropenia (SCN) were examined. We then investigated whether CRISPR/Cas9-mediated gene editing could correct the mutation., Procedure: The proband underwent extensive clinical assessments, such as exome sequencing and bioinformatics analysis, so that pathogenic genes could be identified. Sanger sequencing was also utilized for confirmation. The cell line, 293-ELANE, harboring ELANE mutation was generated, and the mutation was then corrected by CRISPR/Cas9-mediated homology-directed repair (HDR)., Results: The ELANE gene test in the proband unveiled a heterozygous de novo missense mutation: c. 248T > A (p.V83D), which was not detected in his asymptomatic parents who had provided peripheral blood samples. We found that 46.01% of his father's sperm cells had the same mutation. These results demonstrate that the proband inherited the ELANE mutation from his father, who had an average neutrophil count but had a germline mosaicism. The highest repair efficiency of CRISPR/Cas9-mediated HDR for 293-ELANE is 4.43%., Conclusions: We identified a missense mutation (p.V83D) in ELANE that causes SCN. This is the first report on paternal semen mosaicism of an ELANE mutation. Our study paves the way for preimplantation genetic diagnosis (PGD) based on ELANE mutation prevention and clinical treatment of congenital disabilities., (Copyright © 2021. Published by Elsevier B.V.)

Aims: Congenital neutropaenia is a rare inherited disorder that mainly affects neutrophils causing severe infection. Mutations in several genes have been implicated in the disease pathogenesis. The genetic defects may vary in different populations, influenced by ethnicity and geographical location. Here we describe the clinical and genotypic characteristics of seven unrelated Thai cases with congenital neutropaenia., Methods: Seven unrelated patients with congenital neutropaenia were enrolled (5 female and 2 male) at King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Clinical and laboratory data were collected. Whole exome sequencing (WES) analysis was performed in all cases., Results: WES successfully identified disease-causing mutations in the ELANE gene in all cases, including two novel ones: a heterozygous 12 base pair (bp) inframe insertion (c.289&#95;300dupCAGGTGTTCGCC; p.Q97&#95;A100dup) and a heterozygous 18 bp inframe deletion (c.698&#95;715delCCCCGGTGGCACAGTTTG; p.A233&#95;F238delAPVAQF). Five other previously described ELANE mutations (p.Arg103Pro, p.Gly214Arg, p.Trp241X, p.Ser126Leu and p.Leu47Arg) were also detected., Conclusions: All Thai patients with congenital neutropaenia in this study harboured causative mutations in the ELANE gene, suggesting it the most common associated with the disease. Two novel mutations were also identified, expanding the genotypic spectrum of ELANE ., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Leishmania donovani is a protozoan parasite that causes visceral leishmaniasis, provoking liver and spleen tissue destruction that is lethal unless treated. The parasite replicates in macrophages and modulates host microbicidal responses. We have previously reported that neutrophil elastase (NE) is required to sustain L. donovani intracellular growth in macrophages through the induction of interferon beta (IFN-β). Here, we show that the gene expression of IFN-β by infected macrophages was reduced by half when TLR4 was blocked by pre-treatment with neutralizing antibodies or in macrophages from tlr2 -/- mice, while the levels in macrophages from myd 88 -/- mice were comparable to those from wild-type C57BL/6 mice. The neutralization of TLR4 in tlr2 -/- macrophages completely abolished induction of IFN-β gene expression upon parasite infection, indicating an additive role for both TLRs. Induction of type I interferon (IFN-I), OASL2, SOD1, and IL10 gene expression by L. donovani was completely abolished in macrophages from NE knock-out mice ( ela2 -/- ) or from protein kinase R (PKR) knock-out mice ( pkr -/- ), and in C57BL/6 macrophages infected with transgenic L. donovani expressing the inhibitor of serine peptidase 2 (ISP2). Parasite intracellular growth was impaired in pkr -/- macrophages but was fully restored by the addition of exogenous IFN-β, and parasite burdens were reduced in the spleen of pkr -/- mice at 7 days, as compared to the 129Sv/Ev background mice. Furthermore, parasites were unable to grow in macrophages lacking TLR3, which correlated with lack of IFN-I gene expression. Thus, L. donovani engages innate responses in infected macrophages via TLR2, TLR4, and TLR3, via downstream PKR, to induce the expression of pro-survival genes in the host cell, and guarantee parasite intracellular development., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Dias, Goundry, Vivarini, Costa, Mottram, Lopes and Lima.)

Matrix metalloproteinase-13 (MMP-13) is a uniquely important collagenase that promotes the irreversible destruction of cartilage collagen in osteoarthritis (OA). Collagenase activation is a key control point for cartilage breakdown to occur, yet our understanding of the proteinases involved in this process is limited. Neutrophil elastase (NE) is a well-described proteoglycan-degrading enzyme which is historically associated with inflammatory arthritis, but more recent evidence suggests a potential role in OA. In this study, we investigated the effect of neutrophil elastase on OA cartilage collagen destruction and collagenase activation. Neutrophil elastase induced significant collagen destruction from human OA cartilage ex vivo, in an MMP-dependent manner. In vitro, neutrophil elastase directly and robustly activated pro-MMP-13, and N-terminal sequencing identified cleavage close to the cysteine switch at 72 MKKPR, ultimately resulting in the fully active form with the neo-N terminus of 85 YNVFP. Mole-per-mole, activation was more potent than by MMP-3, a classical collagenase activator. Elastase was detectable in human OA synovial fluid and OA synovia which displayed histologically graded evidence of synovitis. Bioinformatic analyses demonstrated that, compared with other tissues, control cartilage exhibited remarkably high transcript levels of the major elastase inhibitor, (AAT) alpha-1 antitrypsin (gene name SERPINA1), but these were reduced in OA. AAT was located predominantly in superficial cartilage zones, and staining enhanced in regions of cartilage damage. Finally, active MMP-13 specifically inactivated AAT by removal of the serine proteinase cleavage/inhibition site. Taken together, this study identifies elastase as a novel activator of pro-MMP-13 that has relevance for cartilage collagen destruction in OA patients with synovitis., (© 2021 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Stroke is among the top ten causes of death in children but has received disproportionally little attention. Cerebral arteriopathies account for up to 80% of childhood arterial ischemic stroke (CAIS) cases and are strongly predictive of CAIS recurrence and poorer outcomes. The underlying mechanisms of sensitization of neurovasculature by viral infection are undefined. In the first age-appropriate model for childhood arteriopathy-by administration of viral mimetic TLR3-agonist Polyinosinic:polycytidylic acid (Poly-IC) in juvenile mice-we identified a key role of the TLR3-neutrophil axis in disrupting the structural-functional integrity of the blood-brain barrier (BBB) and distorting the developing neurovascular architecture and vascular networks. First, using an array of in-vivo/post-vivo vascular imaging, genetic, enzymatic and pharmacological approaches, we report marked Poly-IC-mediated extravascular leakage of albumin (66kDa) and of a small molecule DiI (∼934Da) and disrupted tight junctions. Poly-IC also enhanced the neuroinflammatory milieu, promoted neutrophil recruitment, profoundly upregulated neutrophil elastase (NE), and induced neutrophil extracellular trap formation (NETosis). Finally, we show that functional BBB disturbances, NETosis and neuroinflammation are markedly attenuated by pharmacological inhibition of NE (Sivelestat). Altogether, these data reveal NE/NETosis as a novel therapeutic target for viral-induced cerebral arteriopathies in children.

Background: Patients with ELANE variants and severe congenital neutropenia (SCN) commonly develop oral complications. Whether they are caused only by low neutrophil count or the combination of neutropenia and aberrant dental cells is unknown., Methods: Genetic variant was identified with exome sequencing. Dental pulp cells isolated from the SCN patient with an ELANE mutation were investigated for gene expression, enzyme activity, proliferation, colony formation, wound healing, apoptosis, ROS, attachment, spreading and response to lipopolysaccharide., Results: ELANE cells had diminished expression of ELANE and SLPI and reduced neutrophil elastase activity. Moreover, ELANE cells exhibited impaired proliferation, colony forming, migration, attachment and spreading; and significantly increased ROS formation and apoptosis, corresponding with increased Cyclin D1 and MMP2 levels. The intrinsic levels of TGF-β1 and TNF-α were significantly increased; however, IL-6, IL-8 and NF-kB1 were significantly decreased in ELANE cells compared with those in controls. After exposure to lipopolysaccharide, ELANE cells grew larger, progressed to more advanced cell spreading stages and showed significantly increased SLPI, TNF-α and NF-kB1 and tremendously increased IL-6 and IL-8 expression, compared with controls., Conclusion: This study, for the first time, suggests that in addition to neutropenia, the aberrant levels and functions of ELANE, SLPI and their downstream molecules in pulp cells play an important role in oral complications in SCN patients. In addition, pulp cells with diminished neutrophil elastase and SLPI are highly responsive to inflammation., (© 2021 The Authors. Cell Proliferation published by John Wiley & Sons Ltd.)

Cyclic neutropenia has been rarely associated with chronic inflammation and development of reactive AA amyloidosis. We report a family with cyclic neutropenia with associated renal and thyroid amyloid. A 12-year-old female presented with thyromegaly, recurrent aphthous ulcers, severe neutropenia, and renal failure. Renal and thyroid biopsies revealed abundant amyloid deposition. Presence of a heterozygous ELANE c.358 A>T gene mutation p.I120F variant with autosomal dominant inheritance confirmed the diagnosis of cyclic neutropenia. The patient's father also had neutropenia and amyloidosis with renal failure. We started filgrastim to attenuate neutropenia and thereby reduce chronic inflammation and minimize further amyloid deposition., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Human neutrophil elastase (HNE) is a uniquely destructive serine protease with the ability to unleash a wave of proteolytic activity by destroying the inhibitors of other proteases. Although this phenomenon forms an important part of the innate immune response to invading pathogens, it is responsible for the collateral host tissue damage observed in chronic conditions such as chronic obstructive pulmonary disease (COPD), and in more acute disorders such as the lung injuries associated with COVID-19 infection. Previously, a combinatorially selected activity-based probe revealed an unexpected substrate preference for oxidised methionine, which suggests a link to oxidative pathogen clearance by neutrophils. Here we use oxidised model substrates and inhibitors to confirm this observation and to show that neutrophil elastase is specifically selective for the di-oxygenated methionine sulfone rather than the mono-oxygenated methionine sulfoxide. We also posit a critical role for ordered solvent in the mechanism of HNE discrimination between the two oxidised forms methionine residue. Preference for the sulfone form of oxidised methionine is especially significant. While both host and pathogens have the ability to reduce methionine sulfoxide back to methionine, a biological pathway to reduce methionine sulfone is not known. Taken together, these data suggest that the oxidative activity of neutrophils may create rapidly cleaved elastase "super substrates" that directly damage tissue, while initiating a cycle of neutrophil oxidation that increases elastase tissue damage and further neutrophil recruitment.

Among 143 patients with elastase, neutrophil-expressed (ELANE)-related neutropenia enrolled in the French Severe Chronic Neutropenia Registry, 94 were classified as having severe chronic neutropenia (SCN) and 49 with cyclic neutropenia (CyN). Their infectious episodes were classified as severe, mild or oral, and analysed according to their natural occurrence without granulocyte-colony stimulating factor (G-CSF), on G-CSF, after myelodysplasia/acute leukaemia or after haematopoietic stem-cell transplantation. During the disease's natural history period (without G-CSF; 1913 person-years), 302, 957 and 754 severe, mild and oral infectious events, respectively, occurred. Among severe infections, cellulitis (48%) and pneumonia (38%) were the most common. Only 38% of episodes were microbiologically documented. The most frequent pathogens were Staphylococcus aureus (37·4%), Escherichia coli (20%) and Pseudomonas aeruginosa (16%), while fungal infections accounted for 1%. Profound neutropenia (<200/mm 3 ), high lymphocyte count (>3000/mm 3 ) and neutropenia subtype were associated with high risk of infection. Only the p.Gly214Arg variant (5% of the patients) was associated with infections but not the overall genotype. The first year of life was associated with the highest infection risk throughout life. G-CSF therapy achieved lower ratios of serious or oral infectious event numbers per period but was less protective for patients requiring >10 µg/kg/day. Infections had permanent consequences in 33% of patients, most frequently edentulism., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Patients with cystic fibrosis (CF) have defective macrophage phagocytosis and efferocytosis. Several reports demonstrate that neutrophil elastase (NE), a major inflammatory protease in the CF airway, impairs macrophage phagocytic function. To date, NE-impaired macrophage phagocytic function has been attributed to cleavage of cell surface receptors or opsonins. We applied an unbiased proteomic approach to identify other potential macrophage targets of NE protease activity that may regulate phagocytic function. Using the murine macrophage cell line, RAW 264.7, human blood monocyte-derived macrophages, and primary alveolar macrophages from Cftr-null and wild-type littermate mice, we demonstrated that NE exposure blocked phagocytosis of Escherichia coli bio-particles. We performed liquid chromatography-tandem mass spectroscopy (LC-MS/MS) proteomic analysis of the conditioned media from RAW264.7 treated either with active NE or inactive (boiled) NE as a control. Out of 840 proteins identified in the conditioned media, active NE upregulated 142 proteins and downregulated 211 proteins. NE released not only cell surface proteins into the media but also cytoskeletal, mitochondrial, cytosolic, and nuclear proteins that were detected in the conditioned media. At least 32 proteins were associated with the process of phagocytosis including 11 phagocytic receptors [including lipoprotein receptor-related protein 1 (LRP1)], 7 proteins associated with phagocytic cup formation, and 14 proteins involved in phagocytic maturation (including calpain-2) and phagolysosome formation. NE had a broad effect on the proteome required for regulation of all stages of phagocytosis and phagolysosome formation. Furthermore, the NE sheddome/secretome included proteins from other macrophage cellular domains, suggesting that NE may globally regulate macrophage structure and function.

Chromatin undergoes extensive reprogramming during immune cell differentiation. Here we report the repression of controlled histone H3 amino terminus proteolytic cleavage (H3ΔN) during monocyte-to-macrophage development. This abundant histone mark in human peripheral blood monocytes is catalyzed by neutrophil serine proteases (NSPs) cathepsin G, neutrophil elastase and proteinase 3. NSPs are repressed as monocytes mature into macrophages. Integrative epigenomic analysis reveals widespread H3ΔN distribution across the genome in a monocytic cell line and primary monocytes, which becomes largely undetectable in fully differentiated macrophages. H3ΔN is enriched at permissive chromatin and actively transcribed genes. Simultaneous NSP depletion in monocytic cells results in H3ΔN loss and further increase in chromatin accessibility, which likely primes the chromatin for gene expression reprogramming. Importantly, H3ΔN is reduced in monocytes from patients with systemic juvenile idiopathic arthritis, an autoinflammatory disease with prominent macrophage involvement. Overall, we uncover an epigenetic mechanism that primes the chromatin to facilitate macrophage development.

In this issue of Cell Stem Cell, Daniel Bauer and colleagues investigate the pathogenesis of ELANE-associated severe congenital neutropenia (SCN) and describe two potentially universal gene correction strategies for autosomal dominant disorders (Rao et al., 2021). One exploits nonsense-mediated decay to prevent translation of the mutant allele. The other unexpectedly blocks translation by shortening the 3'-UTR., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Severe congenital neutropenia (SCN) is a life-threatening disorder most often caused by dominant mutations of ELANE that interfere with neutrophil maturation. We conducted a pooled CRISPR screen in human hematopoietic stem and progenitor cells (HSPCs) that correlated ELANE mutations with neutrophil maturation potential. Highly efficient gene editing of early exons elicited nonsense-mediated decay (NMD), overcame neutrophil maturation arrest in HSPCs from ELANE-mutant SCN patients, and produced normal hematopoietic engraftment function. Conversely, terminal exon frameshift alleles that mimic SCN-associated mutations escaped NMD, recapitulated neutrophil maturation arrest, and established an animal model of ELANE-mutant SCN. Surprisingly, only -1 frame insertions or deletions (indels) impeded neutrophil maturation, whereas -2 frame late exon indels repressed translation and supported neutrophil maturation. Gene editing of primary HSPCs allowed faithful identification of variant pathogenicity to clarify molecular mechanisms of disease and encourage a universal therapeutic approach to ELANE-mutant neutropenia, returning normal neutrophil production and preserving HSPC function., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Severe congenital neutropenia (SCN) is a rare hematological condition with heterogenous genetic background. Neutrophil elastase (NE) encoded by ELANE gene is mutated in over half of the SCN cases. The role of NE defects in myelocytes maturation arrest in bone marrow is widely investigated; however, the mechanism underlying this phenomenon has still remained unclear. In this review, we sum up the studies exploring mechanisms of neutrophil deficiency, biological role of NE in neutrophil and the effects of ELANE mutation and neutropenia pathogenesis. We also explain the hypotheses presented so far and summarize options of neutropenia therapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Rydzynska, Pawlik, Krzyzanowski, Mlynarski and Madzio.)

Mutations in ELANE cause severe congenital neutropenia (SCN), but how they affect neutrophil production and contribute to leukemia predisposition is unknown. Neutropenia is alleviated by CSF3 (granulocyte colony-stimulating factor) therapy in most cases, but dose requirements vary between patients. Here, we show that CD34+CD45+ hematopoietic progenitor cells (HPCs) derived from induced pluripotent stem cell lines from patients with SCN that have mutations in ELANE (n = 2) or HAX1 (n = 1) display elevated levels of reactive oxygen species (ROS) relative to normal iPSC-derived HPCs. In patients with ELANE mutations causing misfolding of the neutrophil elastase (NE) protein, HPCs contained elevated numbers of promyelocyte leukemia protein nuclear bodies, a hallmark of acute oxidative stress. This was confirmed in primary bone marrow cells from 3 additional patients with ELANE-mutant SCN. Apart from responding to elevated ROS levels, PML controlled the metabolic state of these ELANE-mutant HPCs as well as the expression of ELANE, suggestive of a feed-forward mechanism of disease development. Both PML deletion and correction of the ELANE mutation restored CSF3 responses of these ELANE-mutant HPCs. These findings suggest that PML plays a crucial role in the disease course of ELANE-SCN characterized by NE misfolding, with potential implications for CSF3 therapy., (© 2021 by The American Society of Hematology.)

Emerging evidence indicates that early life events can increase the risk for developing chronic obstructive pulmonary disease (COPD). Using an inducible transgenic mouse model for NF-κB activation in the airway epithelium, we found that a brief period of inflammation during the saccular stage (P3-P5) but not alveolar stage (P10-P12) of lung development disrupted elastic fiber assembly, resulting in permanent reduction in lung function and development of a COPD-like lung phenotype that progressed through 24 months of age. Neutrophil depletion prevented disruption of elastic fiber assembly and restored normal lung development. Mechanistic studies uncovered a role for neutrophil elastase (NE) in downregulating expression of critical elastic fiber assembly components, particularly fibulin-5 and elastin. Further, purified human NE and NE-containing exosomes from tracheal aspirates of premature infants with lung inflammation downregulated elastin and fibulin-5 expression by saccular-stage mouse lung fibroblasts. Together, our studies define a critical developmental window for assembling the elastin scaffold in the distal lung, which is required to support lung structure and function throughout the lifespan. Although neutrophils play a well-recognized role in COPD development in adults, neutrophilic inflammation may also contribute to early-life predisposition to COPD.

Severe congenital neutropenia (SCN) is a monogenic disorder. SCN patients are prone to recurrent life-threatening infections. The main causes of SCN are autosomal dominant mutations in the ELANE gene that lead to a block in neutrophil differentiation. In this study, we use CRISPR-Cas9 ribonucleoproteins and adeno-associated virus (AAV)6 as a donor template delivery system to repair the ELANE L172P mutation in SCN patient-derived hematopoietic stem and progenitor cells (HSPCs). We used a single guide RNA (sgRNA) specifically targeting the mutant allele, and an sgRNA targeting exon 4 of ELANE. Using the latter sgRNA, ∼34% of the known ELANE mutations can in principle be repaired. We achieved gene correction efficiencies of up to 40% (with sgELANE-ex4) and 56% (with sgELANE-L172P) in the SCN patient-derived HSPCs. Gene repair restored neutrophil differentiation in vitro and in vivo upon HSPC transplantation into humanized mice. Mature edited neutrophils expressed normal elastase levels and behaved normally in functional assays. Thus, we provide a proof of principle for using CRISPR-Cas9 to correct ELANE mutations in patient-derived HSPCs, which may translate into gene therapy for SCN., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To delineate the clinical feature and genetic basis of four patients with congenital neutropenia., Methods: All patients were subjected to whole exome sequencing (WES). Suspected variants were verified by Sanger sequencing., Results: The patients (two boys and two girls), aged 7 to 15 months, suffered from neutropenia and recurrent infections. Bone marrow smears showed a significant decrease in the proportion of rod-shaped and lobulated granulocytes, which suggested impaired development and maturation of bone marrow neutrophils. WES has discovered heterozygous variants (c.496G>A, c.58C>G, c.391G>A and IVS1+5T>A) of the ELANE gene in the patients. Among these, c.58C>G and IVS1+5T>A were unreported previously. Follow up revealed patients 1 and 3 had periodic neutropenia, while patients 2 and 4 had severe congenital neutropenia. After attaining the definite diagnosis, the patients were treated symptomatically., Conclusion: The main clinical feature of congenital neutropenia is refractory recurrent bacterial infections, for which mutations of the ELANE gene are a common cause. Two novel pathogenic ELANE variants have been discovered in this study.

Background: The prevalence and mortality of the outbreak of the COVID-19 pandemic show marked geographic variation. The presence of several subtypes of the coronavirus and the genetic differences in the populations could condition that variation. Thus, the objective of this study was to propose variants in genes that encode proteins related to the SARS-CoV-2 entry into the host cells as possible targets for genetic associations studies., Methods: The allelic frequencies of the polymorphisms in the ACE2, TMPRSS2, TMPRSS11A, cathepsin L (CTSL), and elastase (ELANE) genes were obtained in four populations from the American, African, European, and Asian continents reported in the 1000 Genome Project. Moreover, we evaluated the potential biological effect of these variants using different web-based tools., Results: In the coding sequences of these genes, we detected one probably-damaging polymorphism located in the TMPRSS2 gene (rs12329760) that produces a change of amino acid. Furthermore, forty-eight polymorphisms with possible functional consequences were detected in the non-coding sequences of the following genes: three in ACE2, seventeen in TMPRSS2, ten in TMPRSS11A, twelve in ELANE, and six in CTSL. These polymorphisms produce binding sites for transcription factors and microRNAs. The minor allele frequencies of these polymorphisms vary in each community; indeed, some of them are high in specific populations., Conclusion: In summary, using data of the 1000 Genome Project and web-based tools, we propose some polymorphisms, which, depending on the population, could be used for genetic association studies., (Copyright © 2020. Published by Elsevier Inc.)