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Mediators of Inflammation 2022Our previous work has shown that inflammatory processes play a detrimental role in the pathophysiology of acute ischemic stroke (AIS). Neutrophil extracellular traps...
BACKGROUND
Our previous work has shown that inflammatory processes play a detrimental role in the pathophysiology of acute ischemic stroke (AIS). Neutrophil extracellular traps (NETs) have been recognized as a key contributor to the proinflammatory response in AIS and could aggravate blood-brain barrier (BBB) damage. Recently, experimental and clinical researches showed that Edaravone Dexborneol (Eda.B), which is comprised of two active ingredients, Edaravone and (+)-Borneol, was effective in treatment of AIS. However, it is not clear whether the effects of Eda.B against AIS are related to NETs and BBB permeability.
METHODS
Experiment 1 was to detect the effects of Eda.B in AIS patients. Serum samples of volunteers and AIS patients were collected before and 3 days after Edaravone Dexborneol treatment. Markers of NETs and occludin were detected by ELISA kit. Experiment 2 was to explore the effects of Eda.B on experimental stroke mice. Male C57BL/6 mice were subjected to distal middle cerebral artery occlusion (MCAO) and treated with vehicle, Eda.B, or DeoxyribonueleaseI (DNase I). After stroke, the neurobehavioral tests, infarct volume, and cerebral blood flow evaluation were determined. Leakage of Evans blue was to assess the integrity of BBB. Western blot, real-time quantitative polymerase chain reaction (RT-qPCR), and immunofluorescence were used to examine the expression of NETs and tight junction- (TJ-) associated proteins.
RESULTS
Eda.B significantly improved neurological function and cerebral blood flow but reduced infarct volume after experimental stroke. Eda.B downregulated level of NETs in serum samples of AIS patients and tissue samples of MCAO mouse cortex. Eda.B and DNase I alleviated BBB permeability by upregulating TJ-associated proteins.
CONCLUSION
NETs are related to the early stage of AIS. Eda.B exerted neuroprotective effects and ameliorated BBB permeability after AIS.
Topics: Animals; Blood-Brain Barrier; Brain Ischemia; Deoxyribonuclease I; Edaravone; Extracellular Traps; Humans; Infarction, Middle Cerebral Artery; Ischemic Stroke; Male; Mice; Mice, Inbred C57BL; Permeability; Stroke
PubMed: 36032782
DOI: 10.1155/2022/3855698 -
The Journal of Experimental Medicine Jun 2023DNASE1 (D1) and DNASE1L3 (D1L3) synergistically reduce the severity of systemic infections caused by Staphylococcus aureus. In this issue of JEM, Lacey et al. (2023. J....
DNASE1 (D1) and DNASE1L3 (D1L3) synergistically reduce the severity of systemic infections caused by Staphylococcus aureus. In this issue of JEM, Lacey et al. (2023. J. Exp. Med.https://doi.org/10.1084/jem.20221086) develop D1-/-, D1L3-/-, and D1-/-D1L3-/- mice to show that exogenous addition of the DNase formulation Dornase alfa can facilitate removal of biofilms.
Topics: Mice; Animals; Endodeoxyribonucleases
PubMed: 37129875
DOI: 10.1084/jem.20230421 -
Frontiers in Immunology 2023Neutrophil Extracellular Traps (NETs) are key mediators of immunothrombotic mechanisms and defective clearance of NETs from the circulation underlies an array of...
BACKGROUND
Neutrophil Extracellular Traps (NETs) are key mediators of immunothrombotic mechanisms and defective clearance of NETs from the circulation underlies an array of thrombotic, inflammatory, infectious, and autoimmune diseases. Efficient NET degradation depends on the combined activity of two distinct DNases, DNase1 and DNase1-like 3 (DNase1L3) that preferentially digest double-stranded DNA (dsDNA) and chromatin, respectively.
METHODS
Here, we engineered a dual-active DNase with combined DNase1 and DNase1L3 activities and characterized the enzyme for its NET degrading potential in vitro. Furthermore, we produced a mouse model with transgenic expression of the dual-active DNase and analyzed body fluids of these animals for DNase1 and DNase 1L3 activities. We systematically substituted 20 amino acid stretches in DNase1 that were not conserved among DNase1 and DNase1L3 with homologous DNase1L3 sequences.
RESULTS
We found that the ability of DNase1L3 to degrade chromatin is embedded into three discrete areas of the enzyme's core body, not the C-terminal domain as suggested by the state-of-the-art. Further, combined transfer of the aforementioned areas of DNase1L3 to DNase1 generated a dual-active DNase1 enzyme with additional chromatin degrading activity. The dual-active DNase1 mutant was superior to native DNase1 and DNase1L3 in degrading dsDNA and chromatin, respectively. Transgenic expression of the dual-active DNase1 mutant in hepatocytes of mice lacking endogenous DNases revealed that the engineered enzyme was stable in the circulation, released into serum and filtered to the bile but not into the urine.
CONCLUSION
Therefore, the dual-active DNase1 mutant is a promising tool for neutralization of DNA and NETs with potential therapeutic applications for interference with thromboinflammatory disease states.
Topics: Mice; Animals; Endodeoxyribonucleases; Extracellular Traps; Deoxyribonuclease I; Chromatin; DNA; Deoxyribonucleases
PubMed: 37287977
DOI: 10.3389/fimmu.2023.1181761 -
Biomolecules Jul 2020Extracellular DNA, also called cell-free DNA, released from dying cells or activated immune cells can be recognized by the immune system as a danger signal causing or... (Review)
Review
Extracellular DNA, also called cell-free DNA, released from dying cells or activated immune cells can be recognized by the immune system as a danger signal causing or enhancing inflammation. The cleavage of extracellular DNA is crucial for limiting the inflammatory response and maintaining homeostasis. Deoxyribonucleases (DNases) as enzymes that degrade DNA are hypothesized to play a key role in this process as a determinant of the variable concentration of extracellular DNA. DNases are divided into two families-DNase I and DNase II, according to their biochemical and biological properties as well as the tissue-specific production. Studies have shown that low DNase activity is both, a biomarker and a pathogenic factor in systemic lupus erythematosus. Interventional experiments proved that administration of exogenous DNase has beneficial effects in inflammatory diseases. Recombinant human DNase reduces mucus viscosity in lungs and is used for the treatment of patients with cystic fibrosis. This review summarizes the currently available published data about DNases, their activity as a potential biomarker and methods used for their assessment. An overview of the experiments with systemic administration of DNase is also included. Whether low-plasma DNase activity is involved in the etiopathogenesis of diseases remains unknown and needs to be elucidated.
Topics: Biomarkers; Cell-Free Nucleic Acids; Cystic Fibrosis; Deoxyribonucleases; Humans; Lupus Erythematosus, Systemic; Organ Specificity
PubMed: 32664541
DOI: 10.3390/biom10071036 -
Thrombosis Research May 2022The hypercoagulable state associated with malignancy is well described. However, the mechanisms by which tumors cause this hypercoagulable state are yet to be fully... (Review)
Review
The hypercoagulable state associated with malignancy is well described. However, the mechanisms by which tumors cause this hypercoagulable state are yet to be fully understood. This review summarizes the available literature of human and animal studies examining NETs and cancer-associated thrombosis. The methods for detecting and quantifying NET formation are growing but are not yet standardized in practice. Furthermore, it is important to distinguish between measuring neutrophil activation and NET formation, as the former can be present without the latter. Citrullination of histones by peptidylarginine deiminase 4 (PAD4) is considered one of the key pathways leading to NET formation. Cancer cells can prime neutrophils toward NET formation through the release of soluble mediators, such as interleukin-8, and activation of platelets, and may cause excess NET formation. Dismantling NETs through exogenous deoxyribonuclease has been shown to degrade NETs and reduce thrombus formation in vitro but may simultaneously release prothrombotic NET components, such as DNA and histones. Inhibiting PAD4 is far from clinical trials, but animal models show promising results with a potentially favorable safety profile. Interestingly, results from animal studies suggest that several therapies approved for other indications, such as interleukin-1 receptor blockade and JAK inhibition, may mitigate excessive NET formation or the prothrombotic effects of NETs in cancer. It is yet to be determined if inhibition of NET formation reduces cancer-associated thrombosis also in the clinical setting.
Topics: Animals; DNA; Deoxyribonucleases; Extracellular Traps; Histones; Humans; Interleukin-8; Neoplasms; Neutrophils; Protein-Arginine Deiminases; Receptors, Interleukin-1; Thrombophilia; Thrombosis
PubMed: 36210559
DOI: 10.1016/j.thromres.2021.12.018 -
Nature Biotechnology Mar 2024A number of mitochondrial diseases in humans are caused by point mutations that could be corrected by base editors, but delivery of CRISPR guide RNAs into the...
A number of mitochondrial diseases in humans are caused by point mutations that could be corrected by base editors, but delivery of CRISPR guide RNAs into the mitochondria is difficult. In this study, we present mitochondrial DNA base editors (mitoBEs), which combine a transcription activator-like effector (TALE)-fused nickase and a deaminase for precise base editing in mitochondrial DNA. Combining mitochondria-localized, programmable TALE binding proteins with the nickase MutH or Nt.BspD6I(C) and either the single-stranded DNA-specific adenine deaminase TadA8e or the cytosine deaminase ABOBEC1 and UGI, we achieve A-to-G or C-to-T base editing with up to 77% efficiency and high specificity. We find that mitoBEs are DNA strand-selective mitochondrial base editors, with editing results more likely to be retained on the nonnicked DNA strand. Furthermore, we correct pathogenic mitochondrial DNA mutations in patient-derived cells by delivering mitoBEs encoded in circular RNAs. mitoBEs offer a precise, efficient DNA editing tool with broad applicability for therapy in mitochondrial genetic diseases.
Topics: Humans; Gene Editing; DNA, Mitochondrial; CRISPR-Cas Systems; RNA, Guide, CRISPR-Cas Systems; Mitochondria; Mitochondrial Diseases; Deoxyribonuclease I; Cytosine
PubMed: 37217751
DOI: 10.1038/s41587-023-01791-y -
Nature Jan 2024Bacteria encode hundreds of diverse defence systems that protect them from viral infection and inhibit phage propagation. Gabija is one of the most prevalent anti-phage...
Bacteria encode hundreds of diverse defence systems that protect them from viral infection and inhibit phage propagation. Gabija is one of the most prevalent anti-phage defence systems, occurring in more than 15% of all sequenced bacterial and archaeal genomes, but the molecular basis of how Gabija defends cells from viral infection remains poorly understood. Here we use X-ray crystallography and cryo-electron microscopy (cryo-EM) to define how Gabija proteins assemble into a supramolecular complex of around 500 kDa that degrades phage DNA. Gabija protein A (GajA) is a DNA endonuclease that tetramerizes to form the core of the anti-phage defence complex. Two sets of Gabija protein B (GajB) dimers dock at opposite sides of the complex and create a 4:4 GajA-GajB assembly (hereafter, GajAB) that is essential for phage resistance in vivo. We show that a phage-encoded protein, Gabija anti-defence 1 (Gad1), directly binds to the Gabija GajAB complex and inactivates defence. A cryo-EM structure of the virally inhibited state shows that Gad1 forms an octameric web that encases the GajAB complex and inhibits DNA recognition and cleavage. Our results reveal the structural basis of assembly of the Gabija anti-phage defence complex and define a unique mechanism of viral immune evasion.
Topics: Bacteria; Bacterial Proteins; Bacteriophages; Cryoelectron Microscopy; Crystallography, X-Ray; Deoxyribonucleases; DNA, Viral; Immune Evasion; Protein Multimerization
PubMed: 37992757
DOI: 10.1038/s41586-023-06855-2 -
DNA Repair Nov 2020Unrepaired, or misrepaired, DNA damage can contribute to the pathogenesis of a number of conditions, or disease states; thus, DNA damage repair pathways, and the... (Review)
Review
Unrepaired, or misrepaired, DNA damage can contribute to the pathogenesis of a number of conditions, or disease states; thus, DNA damage repair pathways, and the proteins within them, are required for the safeguarding of the genome. Human SNM1A is a 5'-to-3' exonuclease that plays a role in multiple DNA damage repair processes. To date, most data suggest a role of SNM1A in primarily ICL repair: SNM1A deficient cells exhibit hypersensitivity to ICL-inducing agents (e.g. mitomycin C and cisplatin); and both in vivo and in vitro experiments demonstrate SNM1A and XPF-ERCC1 can function together in the 'unhooking' step of ICL repair. SNM1A further interacts with a number of other proteins that contribute to genome integrity outside canonical ICL repair (e.g. PCNA and CSB), and these may play a role in regulating SNM1As function, subcellular localisation, and post-translational modification state. These data also provide further insight into other DNA repair pathways to which SNM1A may contribute. This review aims to discuss all aspects of the exonuclease, SNM1A, and its contribution to DNA damage tolerance.
Topics: Animals; Cell Cycle Proteins; DNA; DNA Adducts; DNA Repair; DNA Repair Enzymes; Exodeoxyribonucleases; Humans; Protein Conformation
PubMed: 32866775
DOI: 10.1016/j.dnarep.2020.102941 -
Scientific Reports Nov 2023In search of novel breast cancer (BC) risk variants, we performed a whole-exome sequencing and variant analysis of 69 Finnish BC patients as well as analysed...
In search of novel breast cancer (BC) risk variants, we performed a whole-exome sequencing and variant analysis of 69 Finnish BC patients as well as analysed loss-of-function variants identified in DNA repair genes in the Finns from the Genome Aggregation Database. Additionally, we carried out a validation study of SERPINA3 c.918-1G>C, recently suggested for BC predisposition. We estimated the frequencies of 41 rare candidate variants in 38 genes by genotyping them in 2482-4101 BC patients and in 1273-3985 controls. We further evaluated all coding variants in the candidate genes in a dataset of 18,786 BC patients and 182,927 controls from FinnGen. None of the variants associated significantly with cancer risk in the primary BC series; however, in the FinnGen data, NTHL1 c.244C>T p.(Gln82Ter) associated with BC with a high risk for homozygous (OR = 44.7 [95% CI 6.90-290], P = 6.7 × 10) and a low risk for heterozygous women (OR = 1.39 [1.18-1.64], P = 7.8 × 10). Furthermore, the results suggested a high risk of colorectal, urinary tract, and basal-cell skin cancer for homozygous individuals, supporting NTHL1 as a recessive multi-tumour susceptibility gene. No significant association with BC risk was detected for SERPINA3 or any other evaluated gene.
Topics: Humans; Female; Genetic Predisposition to Disease; Breast Neoplasms; Heterozygote; Breast; Finland; Deoxyribonuclease (Pyrimidine Dimer)
PubMed: 38036545
DOI: 10.1038/s41598-023-47441-w -
Cells Oct 2021Neutrophil extracellular traps (NETs) are macromolecular structures programmed to trap circulating bacteria and viruses. The accumulation of NETs in the circulation... (Review)
Review
Neutrophil extracellular traps (NETs) are macromolecular structures programmed to trap circulating bacteria and viruses. The accumulation of NETs in the circulation correlates with the formation of anti-double-stranded (ds) DNA antibodies and is considered a causative factor for systemic lupus erythematosus (SLE). The digestion of DNA by DNase1 and DNases1L3 is the rate- limiting factor for NET accumulation. Mutations occurring in one of these two DNase genes determine anti-DNA formation and are associated with severe Lupus-like syndromes and lupus nephritis (LN). A second mechanism that may lead to DNase functional impairment is the presence of circulating DNase inhibitors in patients with low DNase activity, or the generation of anti-DNase antibodies. This phenomenon has been described in a relevant number of patients with SLE and may represent an important mechanism determining autoimmunity flares. On the basis of the reviewed studies, it is tempting to suppose that the blockade or selective depletion of anti-DNase autoantibodies could represent a potential novel therapeutic approach to prevent or halt SLE and LN. In general, strategies aimed at reducing NET formation might have a similar impact on the progression of SLE and LN.
Topics: Animals; Antibodies; Autoimmunity; DNA; Deoxyribonucleases; Extracellular Traps; Humans; Mutation
PubMed: 34685647
DOI: 10.3390/cells10102667