Pure mitochondrial DNA does not activate human neutrophils in vitro

Prikhodko, Anastasia S.; Шабанов, А. К.; Zinovkina, L. A.; Попова, Е. Н.; Aznauryan, M. A.; Lanina, Natalia O.; Vitushkina, Maria V.; Zinovkin, Roman A.

doi:10.1134/s0006297915050168

Cited by 18 publications

(13 citation statements)

References 27 publications

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“…It has been shown that levels of mtDNA released into the circulation in trauma patients were markedly elevated in comparison with volunteers, and the released mtDNA induced sterile inflammation . In contrast, highly purified mtDNA was recently demonstrated to be unable to activate neutrophilic responses; thus, neutrophilic activation by mtDNA is now controversial. On the other hand, it is well known that various exogenous N ‐formylated peptides such as fMLF, which is a bacterial protein‐derived N ‐formylated peptide, can activate neutrophils; however, endogenous N ‐formylated peptides responsible for these immune responses in MTDs remain unknown.…”

Section: Introductionmentioning

confidence: 99%

Mitochondrial protein‐derived cryptides: Are endogenous N‐formylated peptides including mitocryptide‐2 components of mitochondrial damage‐associated molecular patterns?

et al. 2016

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Recently, much attention has been paid to "nonclassical" bioactive peptides, which are fragmented peptides simultaneously produced during maturation and degradation of various functional proteins. We identified many fragmented peptides derived from various mitochondrial proteins including mitocryptide-1 and mitocryptide-2 that efficiently activate neutrophils. These endogenous, functionally active, fragmented peptides are referred to as "cryptides." Among them, mitocryptide-2 is an N-formylated cryptide cleaved from mitochondrial cytochrome b that is encoded in mitochondrial DNA (mtDNA). It is known that 13 proteins encoded in mtDNA are translated in mitochondria as N-formylated forms, suggesting the existence of endogenous N-formylated peptides other than mitocryptide-2. Here, we investigated the effects of N-formylated peptides presumably cleaved from mtDNA-encoded proteins other than cytochrome b on the functions of neutrophilic cells to elucidate possible regulation by endogenous N-formylated cryptides. Four N-formylated cryptides derived from cytochrome c oxidase subunit I and NADH dehydrogenase subunits 4, 5, and 6 among 12 peptides from mtDNA-encoded proteins efficiently induced not only migration but also β-hexosaminidase release, which is an indicator of neutrophilic phagocytosis, in HL-60 cells differentiated into neutrophilic cells. These activities were comparable to or higher than those induced by mitocryptide-2. Although endogenous N-formylated peptides that are contained in mitochondrial damage-associated molecular patterns (DAMPs) have yet to be molecularly identified, they have been implicated in innate immunity. Thus, N-formylated cryptides including mitocryptide-2 are first-line candidates for the contents of mitochondrial DAMPs to promote innate immune responses. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 580-587, 2016.

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Section: Introductionmentioning

confidence: 99%

Mitochondrial protein‐derived cryptides: Are endogenous N‐formylated peptides including mitocryptide‐2 components of mitochondrial damage‐associated molecular patterns?

et al. 2016

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“…However, basal, unstimulated, NET formation in our experiments was already low, so that we could only identify a modest drop in NETosis from neutrophils of septic patients. This is interesting, as Zhang et al had shown that mitochondrial DAMPS, being a mixture of mtDNA and mitochondrial proteins stimulate neutrophils (12), whereas highly purified mtDNA alone, as we used it in our experiments, did not activate neutrophils (26). As we and others have shown recently, mtDNA can induce immunosuppressive phenotypes, by inhibiting cytotoxic T-cell activity, both in wildtype mice and humans with sepsis (12,13).…”

Section: Discussionmentioning

confidence: 56%

Neutrophil extracellular trap formation and nuclease activity in septic patients

Cox

Walstein

Völlger

et al. 2019

Preprint

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Background: There is little knowledge, whether in patients with sepsis neutrophil extracellular trap (NET) formation and NET degrading nuclease activity are altered. Thus, we tested the hypotheses that 1) NET formation from neutrophils of septic patients is increased compared to healthy volunteers, both without stimulation and following incubation with mitochondrial DNA (mtDNA), a damage-associated molecular pattern, or phorbol 12-myristate 13-acetate (PMA; positive control); and 2) serum nuclease activities are increased as well. Methods: We included 18 septic patients and 27 volunteers in this prospective observational trial while study was registered retrospectively. Blood was withdrawn and NET formation from neutrophils in vitro was quantified (average percentage of neutrophils showing NET formation on an image) without stimulation and following incubation with mtDNA (10µg/well) or PMA (25nmol). Serum nuclease activity was assessed using gel electrophoresis. Results: In contrast to our hypothesis, compared to healthy volunteers unstimulated NET release from neutrophils in septic patients was decreased by 46.3% (4.3%±1.8 SD vs. 8.2%±2.9, p≤0.0001) and 48.1% (4.9%±2.5 vs. 9.4%±5.2, p=0.002) after 2 and 4 hours of incubation. mtDNA further decreased NET formation in neutrophils from septic patients (4.7%±1.2 to 2.8%±0,8; p=0.03) but did not alter NET formation in neutrophils from volun-teers. As expected, PMA, as positive control, increased NET formation to 73.2% (±29.6) in septic patients and to 91.7% (±7.1) in volunteers after 4 hours of incubation (p=0.22). Serum nuclease activity (range: 0-6) was decreased in septic patients by 39.6% (3±2 vs 5±0; median and ICR, p=0.0001) compared to volunteers. Conclusions: Unstimulated NET formation and nuclease activity are decreased in septic patients and mtDNA can further reduce NET formation. Thus, neutrophils from septic patients show decreased NET formation in vitro despite diminished nuclease activity in vivo. Trail registration DRKS00007694, German Clinical Trials database (DRKS). Registered retrospectively 06.02.2015.

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“…In addition, beyond ALX/FPR2, BOC‐2 may also exert antagonistic effects on FPR1. FPR1 induces neutrophil migration in response to circulating mitochondrial damage‐associated molecular patterns . The BOC‐2 effects can thus be explained by FPR1 signaling inhibition beyond antagonizing LXA 4 activity.…”

Section: Discussionmentioning

confidence: 99%

Therapeutic effect of Lipoxin A4 in malaria-induced acute lung injury

Pádua

Torres

Candéa

et al. 2018

Journal of Leukocyte Biology

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Acute lung injury (ALI) models are characterized by neutrophil accumulation, tissue damage, alteration of the alveolar capillary membrane, and physiological dysfunction. Lipoxin A 4 (LXA 4 ) is an anti-inflammatory eicosanoid that was demonstrated to attenuate lipopolysaccharide-induced ALI. Experimental models of severe malaria can be associated with lung injury. However, to date, a putative effect of LXA 4 on malaria (M)-induced ALI has not been addressed. In this study, we evaluated whether LXA 4 exerts an effect on M-ALI. Male C57BL/6 mice were randomly assigned to the following five groups: noninfected; saline-treated Plasmodium berghei-infected; LXA 4 -pretreated P. berghei-infected (LXA 4 administered 1 h before infection and daily, from days 0 to 5 postinfection), LXA 4 -and LXA 4 receptor antagonist BOC-2-pretreated P. berghei-infected; and LXA 4posttreated P. berghei-infected (LXA 4 administered from days 3 to 5 postinfection). By day 6, pretreatment or posttreatment with LXA 4 ameliorate lung mechanic dysfunction reduced alveolar collapse, thickening and interstitial edema; impaired neutrophil accumulation in the pulmonary tissue and blood; and reduced the systemic production of CXCL1. Additionally, in vitro treatment with LXA 4 prevented neutrophils from migrating toward plasma collected from P. berghei-infected mice. LXA 4 also impaired neutrophil cytoskeleton remodeling by inhibiting F-actin polarization.Ex vivo analysis showed that neutrophils from pretreated and posttreated mice were unable to migrate. In conclusion, we demonstrated that LXA 4 exerted therapeutic effects in malariainduced ALI by inhibiting lung dysfunction, tissue injury, and neutrophil accumulation in lung as well as in peripheral blood. Furthermore, LXA 4 impaired the migratory ability of P. berghei-infected mice neutrophils. K E Y W O R D Scytoskeleton remodeling, lung, LXA 4 receptor, Plasmodium berghei, specialized proresolving mediators INTRODUCTIONMalaria is present in more than 100 countries and accounts for 438,000 deaths each year. 1,2 The most severe form of malaria is Abbreviations: ALI, acute lung injury; ALX/FPR, LXA 4 receptor/formyl peptide receptor; ARDS, acute respiratory distress syndrome; BOC-2, N-Boc-Phe-Leu-Phe-Leu-Phe; CC, C-C motif chemokine; DAD, diffuse alveolar damage; HPFs, high-power fields; LTB 4 , leukotriene B 4 ; LXA 4 , lipoxin A 4 ; MA-ARDS, malaria associated ARDS; M-ALI, malaria induced ALI; Nip, noninfected plasma; Pbp, Plasmodium berghei-infected mouse plasma; PbRBC, Plasmodium berghei parasitized red blood cell; PI, propidium iodide characterized by cerebral dysfunction, which can result in convulsions, long-term neurological deficits, coma, and death. 3,4 Additionally, malaria-associated acute respiratory distress syndrome (MA-ARDS) is a common complication of malaria in adults, and the prevalence of MA-ARDS ranges from 2% to more than 20% of adults with severe malaria, depending on the study area and parasite species. 5,6 Autopsies performed in fatal cases of severe cerebral malaria show l...

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Pure mitochondrial DNA does not activate human neutrophils in vitro

Cited by 18 publications

References 27 publications

Mitochondrial protein‐derived cryptides: Are endogenous N‐formylated peptides including mitocryptide‐2 components of mitochondrial damage‐associated molecular patterns?

Mitochondrial protein‐derived cryptides: Are endogenous N‐formylated peptides including mitocryptide‐2 components of mitochondrial damage‐associated molecular patterns?

Neutrophil extracellular trap formation and nuclease activity in septic patients

Therapeutic effect of Lipoxin A4 in malaria-induced acute lung injury

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