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1.
J Perinatol ; 2024 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-38796522

RESUMEN

BACKGROUND: Fetal Centers use imaging studies to predict congenital diaphragmatic hernia (CDH) prognosis and the need for fetal therapy. Given improving CDH survival, we hypothesized that current fetal imaging severity predictions no longer reflect true outcomes and fail to justify the risks of fetal therapy. METHODS: We analyzed our single-center contemporary data in a left-sided CDH cohort (n = 58) by prognostic criteria determined by MRI observed-to-expected total fetal lung volumes: severe <25%, moderate 25-35%, and mild >35%. We compared contemporary survival to prior studies and the TOTAL trials. RESULTS: Contemporary survival was significantly higher than past studies for all prognostic classifications (mild 100% vs 80-94%, moderate 95% vs 59-75%, severe 79% vs 13-25%; P < 0.01), and to either control or fetal therapy arms of the TOTAL trials. CONCLUSIONS: Current fetal imaging criteria are overly pessimistic and may lead to unwarranted fetal intervention. Fetal therapies remain experimental. Future studies will require updated prognostic criteria.

4.
Am J Pathol ; 193(11): 1776-1788, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-36822266

RESUMEN

Retinopathy of prematurity (ROP), a blinding condition affecting preterm infants, is an interruption of retinal vascular maturation that is incomplete when born preterm. Although ROP demonstrates delayed onset following preterm birth, representing a window for therapeutic intervention, there are no curative or preventative measures available for this condition. The in utero environment, including placental function, is increasingly recognized for contributions to preterm infant disease risk. The current study identified a protective association between acute placental inflammation and preterm infant ROP development using logistic regression, with the most significant association found for infants without gestational exposure to maternal preeclampsia and those with earlier preterm birth. Expression analysis of proteins with described ROP risk associations demonstrated significantly decreased placental high temperature requirement A serine peptidase-1 (HTRA-1) and fatty acid binding protein 4 protein expression in infants with acute placental inflammation compared with those without. Within the postnatal peripheral circulation, HTRA-1 and vascular endothelial growth factor-A demonstrated inverse longitudinal trends for infants born in the presence of, compared with absence of, acute placental inflammation. An agnostic approach, including whole transcriptome and differential methylation placental analysis, further identify novel mediators and pathways that may underly protection. Taken together, these data build on emerging literature showing a protective association between acute placental inflammation and ROP development and identify novel mechanisms that may inform postnatal risk associations in preterm infants.


Asunto(s)
Nacimiento Prematuro , Retinopatía de la Prematuridad , Lactante , Recién Nacido , Humanos , Femenino , Embarazo , Recien Nacido Prematuro , Factor A de Crecimiento Endotelial Vascular , Placenta , Edad Gestacional , Inflamación , Factores de Riesgo
5.
Pediatr Res ; 93(4): 862-869, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-35902703

RESUMEN

BACKGROUND: Treatment of neonatal peritonitis and sepsis is challenging. Following infection, neutrophils elaborate neutrophil extracellular traps (NETs)-extracellular lattices of decondensed chromatin decorated with antimicrobial proteins. NETs, however, can augment pathogenic inflammation causing collateral damage. We hypothesized that NET inhibition would improve survival in experimental neonatal infectious peritonitis. METHODS: We induced peritonitis in 7 to 10-day-old mice by intraperitoneal injection with cecal slurry. We targeted NETs by treating mice with neonatal NET-Inhibitory Factor (nNIF), an endogenous NET-inhibitor; Cl-amidine, a PAD4 inhibitor; DNase I, a NET degrading enzyme, or meropenem (an antibiotic). We determined peritoneal NET and cytokine levels and circulating platelet-neutrophil aggregates. Survival from peritonitis was followed for 6 days. RESULTS: nNIF, Cl-amidine, and DNase I decreased peritoneal NET formation and inflammatory cytokine levels at 24 h compared to controls. nNIF, Cl-amidine, and DNase I decreased circulating platelet-neutrophil aggregates, and NET-targeting treatments significantly increased survival from infectious peritonitis compared to controls. Finally, nNIF administration significantly improved survival in mice treated with sub-optimal doses of meropenem even when treatment was delayed until 2 h after peritonitis induction. CONCLUSIONS: NET inhibition improves survival in experimental neonatal infectious peritonitis, suggesting that NETs participate pathogenically in neonatal peritonitis and sepsis. IMPACT: 1. Neutrophil extracellular trap formation participates pathogenically in experimental neonatal infectious peritonitis. 2. NET-targeting strategies improve outcomes in a translational model of neonatal infectious peritonitis. 3. NET inhibition represents a potential target for drug development in neonatal sepsis and infectious peritonitis.


Asunto(s)
Trampas Extracelulares , Peritonitis , Sepsis , Animales , Ratones , Trampas Extracelulares/metabolismo , Animales Recién Nacidos , Meropenem/metabolismo , Neutrófilos/metabolismo , Peritonitis/tratamiento farmacológico , Peritonitis/metabolismo , Peritonitis/patología , Desoxirribonucleasa I/metabolismo , Sepsis/tratamiento farmacológico , Citocinas/metabolismo , Ratones Endogámicos C57BL
6.
J Clin Invest ; 132(10)2022 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-35358095

RESUMEN

Ischemic stroke prompts a strong inflammatory response, which is associated with exacerbated outcomes. In this study, we investigated mechanistic regulators of neutrophil extracellular trap (NET) formation in stroke and whether they contribute to stroke outcomes. NET-forming neutrophils were found throughout brain tissue of ischemic stroke patients, and elevated plasma NET biomarkers correlated with worse stroke outcomes. Additionally, we observed increased plasma and platelet surface-expressed high-mobility group box 1 (HMGB1) in stroke patients. Mechanistically, platelets were identified as the critical source of HMGB1 that caused NETs in the acute phase of stroke. Depletion of platelets or platelet-specific knockout of HMGB1 significantly reduced plasma HMGB1 and NET levels after stroke, and greatly improved stroke outcomes. We subsequently investigated the therapeutic potential of neonatal NET-inhibitory factor (nNIF) in stroke. Mice treated with nNIF had smaller brain infarcts, improved long-term neurological and motor function, and enhanced survival after stroke. nNIF specifically blocked NET formation without affecting neutrophil recruitment after stroke. Importantly, nNIF also improved stroke outcomes in diabetic and aged mice and was still effective when given 1 hour after stroke onset. These results support a pathological role for NETs in ischemic stroke and warrant further investigation of nNIF for stroke therapy.


Asunto(s)
Lesiones Encefálicas , Trampas Extracelulares , Proteína HMGB1 , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Animales , Proteína HMGB1/genética , Humanos , Ratones , Neutrófilos , Accidente Cerebrovascular/genética
7.
J Pediatr Surg ; 57(9): 17-23, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35216800

RESUMEN

OBJECTIVE: To analyze preoperative cardiopulmonary support and define preoperative stability relative to timing of surgical repair for CDH neonates not on ECMO. STUDY DESIGN: We retrospectively analyzed repeated measures of oxygenation index (OI; Paw*FiO2×100/PaO2) among 158 neonates for temporal preoperative trends. We defined physiologic stability using OI and characterized ventilator days and discharge age relative to delay in repair beyond physiologic stability. RESULTS: The OI in the first 24 h of life was temporally reliable and representative of the preoperative mean (ICC 0.70, 95% CI 0.61-0.77). A pre-operative OI of ≤ 9.4 (AUC 0.95) was predictive of survival. Surgical delay after an OI ≤ 9.4 resulted in increased ventilator days (1.4, 95% CI 1.1-1.9) and discharge age (1.5, 95% CI 1.2-2.0). When prospectively applied to a subsequent cohort, an OI ≤ 9.4 was again reflective of physiologic stability prior to repair. CONCLUSION: OI values are temporally reliable and change minimally after 24 h age. Delay in surgical repair of CDH beyond initial stability increases ventilator days and discharge age without a survival benefit. LEVEL OF EVIDENCE: Prognosis study, Level III.


Asunto(s)
Oxigenación por Membrana Extracorpórea , Hernias Diafragmáticas Congénitas , Análisis de los Gases de la Sangre , Hernias Diafragmáticas Congénitas/cirugía , Humanos , Recién Nacido , Pronóstico , Estudios Retrospectivos
8.
Front Immunol ; 13: 1046574, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36733389

RESUMEN

Introduction: Neutrophil extracellular traps (NETs) clear pathogens but may contribute Q8 pathogenically to host inflammatory tissue damage during sepsis. Innovative therapeutic agents targeting NET formation and their potentially harmful collateral effects remain understudied. Methods: We investigated a novel therapeutic agent, neonatal NET-Inhibitory Factor (nNIF), in a mouse model of experimental sepsis - cecal ligation and puncture (CLP). We administered 2 doses of nNIF (1 mg/ kg) or its scrambled peptide control intravenously 4 and 10 hours after CLP treatment and assessed survival, peritoneal fluid and plasma NET formation using the MPO-DNA ELISA, aerobic bacterial colony forming units (CFU) using serial dilution and culture, peritoneal fluid and stool microbiomes using 16S rRNA gene sequencing, and inflammatory cytokine levels using a multiplexed cytokine array. Meropenem (25 mg/kg) treatment served as a clinically relevant treatment for infection. Results: We observed increased 6-day survival rates in nNIF (73%) and meropenem (80%) treated mice compared to controls (0%). nNIF decreased NET formation compared to controls, while meropenem did not impact NET formation. nNIF treatment led to increased peritoneal fluid and plasma bacterial CFUs consistent with loss of NET-mediated extracellular microbial killing, while nNIF treatment alone did not alter the peritoneal fluid and stool microbiomes compared to vehicle-treated CLP mice. nNIF treatment also decreased peritoneal TNF-a inflammatory cytokine levels compared to scrambled peptide control. Furthermore, adjunctive nNIF increased survival in a model of sub-optimal meropenem treatment (90% v 40%) in CLP-treated mice. Discussion: Thus, our data demonstrate that nNIF inhibits NET formation in a translationally relevant mouse model of sepsis, improves survival when given as monotherapy or as an adjuvant with antibiotics, and may play an important protective role in sepsis.


Asunto(s)
Trampas Extracelulares , Sepsis , Ratones , Animales , Neutrófilos/patología , Meropenem/farmacología , ARN Ribosómico 16S/genética , Sepsis/patología , Citocinas/farmacología , Proteínas Tirosina Quinasas Receptoras , Punciones
9.
Open Forum Infect Dis ; 8(6): ofab237, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34189172

RESUMEN

BACKGROUND: Pneumonia and diarrhea are among the leading causes of death worldwide, and epidemiological studies have demonstrated that diarrhea is associated with an increased risk of subsequent pneumonia. Our aim was to determine the impact of intestinal infection on innate immune responses in the lung. METHODS: Using a mouse model of intestinal infection by Salmonella enterica serovar Typhimurium (S. Typhimurium [ST]), we investigated associations between gastrointestinal infections and lung innate immune responses to bacterial (Klebsiella pneumoniae) challenge. RESULTS: We found alterations in frequencies of innate immune cells in the lungs of intestinally infected mice compared with uninfected mice. On subsequent challenge with K. pneumoniae, we found that mice with prior intestinal infection have higher lung bacterial burden and inflammation, increased neutrophil margination, and neutrophil extracellular traps, but lower overall numbers of neutrophils, compared with mice without prior intestinal infection. Total numbers of dendritic cells, innate-like T cells, and natural killer cells were not different between mice with and without prior intestinal infection. CONCLUSIONS: Together, these results suggest that intestinal infection impacts lung innate immune responses, most notably neutrophil characteristics, potentially resulting in increased susceptibility to secondary pneumonia.

10.
Blood ; 138(11): 977-988, 2021 09 16.
Artículo en Inglés | MEDLINE | ID: mdl-34192300

RESUMEN

Neutrophil extracellular traps (NETs) are important components of innate immunity. Neonatal neutrophils (polymorphonuclear leukocytes [PMNs]) fail to form NETs due to circulating NET-inhibitory peptides (NIPs), cleavage fragments of α1-antitrypsin (A1AT). How fetal and neonatal blood NIPs are generated remains unknown, however. The placenta expresses high-temperature requirement serine protease A1 (HTRA1) during fetal development, which can cleave A1AT. We hypothesized that placentally expressed HTRA1 regulates the formation of NIPs and that NET competency changed in PMNs isolated from neonatal HTRA1 knockout mice (HTRA1-/-). We found that umbilical cord blood plasma has elevated HTRA1 levels compared with adult plasma and that recombinant and placenta-eluted HTRA1 cleaves A1AT to generate an A1AT cleavage fragment (A1ATM383S-CF) of molecular weight similar to previously identified NIPs that block NET formation by adult neutrophils. We showed that neonatal mouse pup plasma contains A1AT fragments that inhibit NET formation by PMNs isolated from adult mice, indicating that NIP generation during gestation is conserved across species. Lipopolysaccharide-stimulated PMNs isolated from HTRA1+/+ littermate control pups exhibit delayed NET formation after birth. However, plasma from HTRA1-/- pups had no detectable NIPs, and PMNs from HTRA1-/- pups became NET competent earlier after birth compared with HTRA1+/+ littermate controls. Finally, in the cecal slurry model of neonatal sepsis, A1ATM383S-CF improved survival in C57BL/6 pups by preventing pathogenic NET formation. Our data indicate that placentally expressed HTRA1 is a serine protease that cleaves A1AT in utero to generate NIPs that regulate NET formation by human and mouse PMNs.


Asunto(s)
Trampas Extracelulares/metabolismo , Serina Peptidasa A1 que Requiere Temperaturas Altas/metabolismo , Placenta/metabolismo , alfa 1-Antitripsina/metabolismo , Animales , Femenino , Humanos , Ratones Endogámicos C57BL , Embarazo , Proteolisis
11.
J Leukoc Biol ; 109(5): 915-930, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33070381

RESUMEN

Alpha-1-acid glycoprotein (AGP-1) is a positive acute phase glycoprotein with uncertain functions. Serum AGP-1 (sAGP-1) is primarily derived from hepatocytes and circulates as 12-20 different glycoforms. We isolated a glycoform secreted from platelet-activating factor (PAF)-stimulated human neutrophils (nAGP-1). Its peptide sequence was identical to hepatocyte-derived sAGP-1, but nAGP-1 differed from sAGP-1 in its chromatographic behavior, electrophoretic mobility, and pattern of glycosylation. The function of these 2 glycoforms also differed. sAGP-1 activated neutrophil adhesion, migration, and neutrophil extracellular traps (NETosis) involving myeloperoxidase, peptidylarginine deiminase 4, and phosphorylation of ERK in a dose-dependent fashion, whereas nAGP-1 was ineffective as an agonist for these events. Furthermore, sAGP-1, but not nAGP-1, inhibited LPS-stimulated NETosis. Interestingly, nAGP-1 inhibited sAGP-1-stimulated neutrophil NETosis. The discordant effect of the differentially glycosylated AGP-1 glycoforms was also observed in platelets where neither of the AGP-1 glycoforms alone stimulated aggregation of washed human platelets, but sAGP-1, and not nAGP-1, inhibited aggregation induced by PAF or ADP, but not by thrombin. These functional effects of sAGP-1 correlated with intracellular cAMP accumulation and phosphorylation of the protein kinase A substrate vasodilator-stimulated phosphoprotein and reduction of Akt, ERK, and p38 phosphorylation. Thus, the sAGP-1 glycoform limits platelet reactivity, whereas nAGP-1 glycoform also limits proinflammatory actions of sAGP-1. These studies identify new functions for this acute phase glycoprotein and demonstrate that the glycosylation of AGP-1 controls its effects on 2 critical cells of acute inflammation.


Asunto(s)
Plaquetas/metabolismo , Neutrófilos/metabolismo , Orosomucoide/metabolismo , Adenosina Difosfato/farmacología , Biomarcadores/metabolismo , Plaquetas/efectos de los fármacos , AMP Cíclico/metabolismo , Trampas Extracelulares/metabolismo , Glicosilación/efectos de los fármacos , Humanos , Modelos Biológicos , Activación Neutrófila/efectos de los fármacos , Neutrófilos/efectos de los fármacos , Orosomucoide/agonistas , Péptidos/metabolismo , Factor de Activación Plaquetaria/farmacología , Agregación Plaquetaria/efectos de los fármacos , Polisacáridos/metabolismo , Isoformas de Proteínas/metabolismo
12.
Neonatology ; 117(4): 532-535, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32987391

RESUMEN

We report a novel glucose-6-phosphate dehydrogenase (G6PD) variant (c.1375C>G) discovered in a 3-day-old Hispanic male child from Salt Lake City, UT, USA. This newborn presented with severe hyperbilirubinemia (29.8 mg/dL or 510 µmol/L) and marked hemolysis evidenced by elevated end-tidal carbon monoxide concentration (5.9 ppm, normal <1.7 ppm). Despite a very low prevalence of G6PD deficiency in Hispanic populations, we pursued testing for this condition and found he had low erythrocyte G6PD enzyme activity (2.8 U/g Hb, normal 9.9-16.6 U/g Hb) and a novel G6PD variant. His mother was heterozygous for this same variant, and she had a moderate decrease in G6PD enzyme activity (7.1 U/g Hb). On the basis of these findings, we propose this variant as a novel pathogenic mutation.


Asunto(s)
Deficiencia de Glucosafosfato Deshidrogenasa , Glucosafosfato Deshidrogenasa , Hiperbilirrubinemia , Femenino , Glucosafosfato Deshidrogenasa/genética , Deficiencia de Glucosafosfato Deshidrogenasa/genética , Heterocigoto , Hispánicos o Latinos/genética , Humanos , Hiperbilirrubinemia/genética , Recién Nacido , Masculino
13.
Blood ; 136(11): 1317-1329, 2020 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-32573711

RESUMEN

There is an urgent need to understand the pathogenesis of coronavirus disease 2019 (COVID-19). In particular, thrombotic complications in patients with COVID-19 are common and contribute to organ failure and mortality. Patients with severe COVID-19 present with hemostatic abnormalities that mimic disseminated intravascular coagulopathy associated with sepsis, with the major difference being increased risk of thrombosis rather than bleeding. However, whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection alters platelet function to contribute to the pathophysiology of COVID-19 remains unknown. In this study, we report altered platelet gene expression and functional responses in patients infected with SARS-CoV-2. RNA sequencing demonstrated distinct changes in the gene-expression profile of circulating platelets of COVID-19 patients. Pathway analysis revealed differential gene-expression changes in pathways associated with protein ubiquitination, antigen presentation, and mitochondrial dysfunction. The receptor for SARS-CoV-2 binding, angiotensin-converting enzyme 2 (ACE2), was not detected by messenger RNA (mRNA) or protein in platelets. Surprisingly, mRNA from the SARS-CoV-2 N1 gene was detected in platelets from 2 of 25 COVID-19 patients, suggesting that platelets may take-up SARS-COV-2 mRNA independent of ACE2. Resting platelets from COVID-19 patients had increased P-selectin expression basally and upon activation. Circulating platelet-neutrophil, -monocyte, and -T-cell aggregates were all significantly elevated in COVID-19 patients compared with healthy donors. Furthermore, platelets from COVID-19 patients aggregated faster and showed increased spreading on both fibrinogen and collagen. The increase in platelet activation and aggregation could partially be attributed to increased MAPK pathway activation and thromboxane generation. These findings demonstrate that SARS-CoV-2 infection is associated with platelet hyperreactivity, which may contribute to COVID-19 pathophysiology.


Asunto(s)
Betacoronavirus/aislamiento & purificación , Trastornos de la Coagulación Sanguínea/patología , Plaquetas/patología , Infecciones por Coronavirus/complicaciones , Neumonía Viral/complicaciones , Transcriptoma , Biomarcadores , Trastornos de la Coagulación Sanguínea/genética , Trastornos de la Coagulación Sanguínea/metabolismo , Trastornos de la Coagulación Sanguínea/virología , Plaquetas/metabolismo , Plaquetas/virología , COVID-19 , Estudios de Casos y Controles , Infecciones por Coronavirus/genética , Infecciones por Coronavirus/metabolismo , Infecciones por Coronavirus/virología , Femenino , Estudios de Seguimiento , Perfilación de la Expresión Génica , Humanos , Masculino , Persona de Mediana Edad , Pandemias , Neumonía Viral/genética , Neumonía Viral/metabolismo , Neumonía Viral/virología , Pronóstico , Estudios Prospectivos , SARS-CoV-2
14.
J Exp Med ; 217(6)2020 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-32302401

RESUMEN

Coronavirus disease 2019 (COVID-19) is a novel, viral-induced respiratory disease that in ∼10-15% of patients progresses to acute respiratory distress syndrome (ARDS) triggered by a cytokine storm. In this Perspective, autopsy results and literature are presented supporting the hypothesis that a little known yet powerful function of neutrophils-the ability to form neutrophil extracellular traps (NETs)-may contribute to organ damage and mortality in COVID-19. We show lung infiltration of neutrophils in an autopsy specimen from a patient who succumbed to COVID-19. We discuss prior reports linking aberrant NET formation to pulmonary diseases, thrombosis, mucous secretions in the airways, and cytokine production. If our hypothesis is correct, targeting NETs directly and/or indirectly with existing drugs may reduce the clinical severity of COVID-19.


Asunto(s)
Betacoronavirus , Infecciones por Coronavirus/patología , Trampas Extracelulares , Enfermedades Pulmonares , Neutrófilos/patología , Neumonía Viral/patología , COVID-19 , Infecciones por Coronavirus/complicaciones , Citocinas/metabolismo , Humanos , Enfermedades Pulmonares/etiología , Enfermedades Pulmonares/metabolismo , Enfermedades Pulmonares/patología , Pandemias , Neumonía Viral/complicaciones , SARS-CoV-2
15.
Mol Genet Genomic Med ; 7(7): e00796, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31192527

RESUMEN

BACKGROUND: Exome/genome sequencing (ES/GS) have been recently used in neonatal and pediatric/cardiac intensive care units (NICU and PICU/CICU) to diagnose and care for acutely ill infants, but the effectiveness of targeted gene panels for these purposes remains unknown. METHODS: RapSeq, a newly developed panel targeting 4,503 disease-causing genes, was employed on selected patients in our NICU/PICU/CICU. Twenty trios were sequenced from October 2015 to March 2017. We assessed diagnostic yield, turnaround times, and clinical consequences. RESULTS: A diagnosis was made in 10/20 neonates (50%); eight had de novo variants (ASXL1, CHD, FBN1, KMT2D, FANCB, FLNA, PAX3), one was a compound heterozygote for CHAT, and one had a maternally inherited GNAS variant. Preliminary reports were generated by 9.6 days (mean); final reports after Sanger sequencing at 16.3 days (mean). In all positive infants, the diagnosis changed management. In a case with congenital myasthenia, diagnosis and treatment occurred at 17 days versus 7 months in a historical control. CONCLUSIONS: This study shows that a gene panel that includes the majority of known disease-causing genes can rapidly identify a diagnosis in a large number of tested infants. Due to simpler deployment and interpretation and lower costs, this approach might represent an alternative to ES/GS in the NICU/PICU/CICU.


Asunto(s)
Enfermedad/genética , Diagnóstico Precoz , Pruebas Genéticas/métodos , Diagnóstico , Técnicas y Procedimientos Diagnósticos , Exoma , Femenino , Pruebas Genéticas/economía , Pruebas Genéticas/tendencias , Humanos , Lactante , Recién Nacido , Unidades de Cuidado Intensivo Neonatal/tendencias , Masculino , Secuenciación del Exoma
16.
Pediatr Res ; 86(1): 17-18, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30965353
17.
Pediatr Res ; 86(1): 55-62, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30965356

RESUMEN

BACKGROUND: Dysregulated inflammation leads to morbidity and mortality in neonates. Neutrophil-mediated inflammation can cause inflammatory tissue damage. The mammalian target of rapamycin (mTOR) pathway governs IL-6Rα protein expression in human neutrophils. Shed IL-6Rα then participates in trans-signaling of IL-6/IL-6Rα to cells not otherwise sensitive to IL-6. Signaling to endothelial cells triggers efferocytosis where macrophages limit persistent inflammation by phagocytizing neutrophils. We hypothesized that preterm neonatal PMNs fail to synthesize IL-6Rα due to alterations in mTOR signaling. METHODS: We studied IL-6Rα expression, PAF receptor expression, and mTOR signaling in plasma and PAF-stimulated PMNs isolated from newborn infants and healthy adults using ELISA, real-time RT-PCR, western blotting, flow cytometry, and immunocytochemistry with phospho-specific antibodies. RESULTS: Compared to healthy adults, plasma from neonates contains significantly less soluble IL-6Rα. IL-6Rα mRNA expression in PAF-stimulated PMNs does not differ between neonates and adults, but IL-6Rα protein expression is decreased in preterm neonatal PMNs. Rapamycin, an mTOR inhibitor, blocks IL-6Rα protein expression. mTOR signaling following PAF stimulation is decreased in preterm neonatal PMNs. CONCLUSIONS: Preterm neonatal PMNs exhibit decreased mTOR pathway signaling leading to decreased IL-6Rα synthesis. Decreased synthesis of IL-6Rα by neonatal PMNs may result in decreased IL-6/IL-6Rα trans-signaling with prolonged inflammatory response and increased morbidity.


Asunto(s)
Regulación de la Expresión Génica , Recien Nacido Prematuro , Interleucina-6/sangre , Neutrófilos/metabolismo , Receptores de Interleucina-6/sangre , Serina-Treonina Quinasas TOR/sangre , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Adolescente , Adulto , Proteínas de Ciclo Celular/metabolismo , Células Endoteliales/metabolismo , Sangre Fetal/metabolismo , Humanos , Recién Nacido , Inflamación , Macrófagos/metabolismo , Persona de Mediana Edad , Fagocitosis , Fosforilación , Transducción de Señal , Adulto Joven
18.
J Clin Invest ; 126(10): 3783-3798, 2016 10 03.
Artículo en Inglés | MEDLINE | ID: mdl-27599294

RESUMEN

Neutrophil granulocytes, also called polymorphonuclear leukocytes (PMNs), extrude molecular lattices of decondensed chromatin studded with histones, granule enzymes, and antimicrobial peptides that are referred to as neutrophil extracellular traps (NETs). NETs capture and contain bacteria, viruses, and other pathogens. Nevertheless, experimental evidence indicates that NETs also cause inflammatory vascular and tissue damage, suggesting that identifying pathways that inhibit NET formation may have therapeutic implications. Here, we determined that neonatal NET-inhibitory factor (nNIF) is an inhibitor of NET formation in umbilical cord blood. In human neonatal and adult neutrophils, nNIF inhibits key terminal events in NET formation, including peptidyl arginine deiminase 4 (PAD4) activity, neutrophil nuclear histone citrullination, and nuclear decondensation. We also identified additional nNIF-related peptides (NRPs) that inhibit NET formation. nNIFs and NRPs blocked NET formation induced by pathogens, microbial toxins, and pharmacologic agonists in vitro and in mouse models of infection and systemic inflammation, and they improved mortality in murine models of systemic inflammation, which are associated with NET-induced collateral tissue injury. The identification of NRPs as neutrophil modulators that selectively interrupt NET generation at critical steps suggests their potential as therapeutic agents. Furthermore, our results indicate that nNIF may be an important regulator of NET formation in fetal and neonatal inflammation.


Asunto(s)
Proteínas Sanguíneas/fisiología , Trampas Extracelulares/metabolismo , Neutrófilos/metabolismo , Animales , Células Cultivadas , Ensamble y Desensamble de Cromatina , Sangre Fetal/metabolismo , Histonas/metabolismo , Humanos , Recién Nacido , Inflamación/inmunología , Inflamación/metabolismo , Lipopolisacáridos/farmacología , Masculino , Ratones Endogámicos C57BL , Proteínas de Neoplasias/fisiología , Neutrófilos/inmunología , Procesamiento Proteico-Postraduccional
19.
Physiol Genomics ; 48(8): 616-25, 2016 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-27317589

RESUMEN

Nutrient deprivation suppresses protein synthesis by blocking peptide elongation. Transcriptional upregulation and activation of eukaryotic elongation factor 2 kinase (eEF2K) blocks peptide elongation by phosphorylating eukaryotic elongation factor 2. Previous studies examining placentas from intrauterine growth restricted (IUGR) newborn infants show decreased eEF2K expression and activity despite chronic nutrient deprivation. However, the effect of IUGR on hepatic eEF2K expression in the fetus is unknown. We, therefore, examined the transcriptional regulation of hepatic eEF2K gene expression in a Sprague-Dawley rat model of IUGR. We found decreased hepatic eEF2K mRNA and protein levels in IUGR offspring at birth compared with control, consistent with previous placental observations. Furthermore, the CpG island within the eEF2K promoter demonstrated increased methylation at a critical USF 1/2 transcription factor binding site. In vitro methylation of this binding site caused near complete loss of eEF2K promoter activity, designating this promoter as methylation sensitive. The eEF2K promotor in IUGR offspring also lost the protective histone covalent modifications associated with unmethylated CGIs. In addition, the +1 nucleosome was displaced 3' and RNA polymerase loading was reduced at the IUGR eEF2K promoter. Our findings provide evidence to explain why IUGR-induced chronic nutrient deprivation does not result in the upregulation of eEF2K gene transcription.


Asunto(s)
Quinasa del Factor 2 de Elongación/genética , Retardo del Crecimiento Fetal/genética , Biosíntesis de Proteínas/genética , Animales , Sitios de Unión/genética , Islas de CpG/genética , Epigénesis Genética/genética , Femenino , Feto/metabolismo , Masculino , Nucleosomas/genética , Embarazo , Regiones Promotoras Genéticas/genética , ARN Mensajero/genética , Ratas , Ratas Sprague-Dawley , Transducción de Señal/genética , Transcripción Genética/genética , Regulación hacia Arriba/genética
20.
Shock ; 45(4): 393-403, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26618986

RESUMEN

Dysregulation of the inflammatory response against infection contributes to mortality in sepsis. Inflammation provides critical host defense, but it can cause tissue damage, multiple organ failure, and death. Because the nuclear transcription factor peroxisome proliferator-activated receptor γ (PPARγ) exhibits therapeutic potential, we characterized the role of PPARγ in sepsis. We analyzed severity of clinical signs, survival rates, cytokine production, leukocyte influx, and bacterial clearance in a cecal ligation and puncture (CLP) model of sepsis in Swiss mice. The PPARγ agonist rosiglitazone treatment improved clinical status and mortality, while increasing IL-10 production and decreasing TNF-α and IL-6 levels, and peritoneal neutrophil accumulation 24 h after CLP. We noted increased bacterial killing in rosiglitazone treated mice, correlated with increased generation of reactive oxygen species. Polymorphonuclear leukocytes (PMN) incubated with LPS or Escherichia coli and rosiglitazone increased peritoneal neutrophil extracellular trap (NET)-mediated bacterial killing, an effect reversed by the PPARγ antagonist (GW 9662) treatment. Rosiglitazone also enhanced the release of histones by PMN, a surrogate marker of NET formation, effect abolished by GW 9662. Rosiglitazone modulated the inflammatory response and increased bacterial clearance through PPARγ activation and NET formation, combining immunomodulatory and host-dependent anti-bacterial effects and, therefore, warrants further study as a potential therapeutic agent in sepsis.


Asunto(s)
Escherichia coli/inmunología , Trampas Extracelulares/inmunología , Neutrófilos/inmunología , PPAR gamma/agonistas , Sepsis/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Tiazolidinedionas/farmacología , Anilidas/farmacología , Animales , Modelos Animales de Enfermedad , Masculino , Ratones , PPAR gamma/inmunología , Rosiglitazona , Sepsis/inmunología , Sepsis/microbiología , Sepsis/patología , Transducción de Señal/inmunología
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