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Denorme F, Andrianova I, Cody MJ, Kosaka Y, Campbell RA. Age-specific impact of type I interferons on cerebral thrombosis and inflammation. Blood Adv 2023; 7:6672-6675. [PMID: 37738163 PMCID: PMC10637883 DOI: 10.1182/bloodadvances.2023010495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 09/01/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023] Open
Affiliation(s)
- Frederik Denorme
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Division of Vascular Neurology, Department of Neurology, The University of Utah, Salt Lake City, UT
| | | | - Mark J. Cody
- University of Utah Molecular Medicine Program, Salt Lake City, UT
| | - Yasuhiro Kosaka
- University of Utah Molecular Medicine Program, Salt Lake City, UT
| | - Robert A. Campbell
- University of Utah Molecular Medicine Program, Salt Lake City, UT
- Division of Hematology and Hematologic Malignancies, Department of Internal Medicine, The University of Utah, Salt Lake City, UT
- Division of Microbiology and Immunology, Department of Pathology, The University of Utah, Salt Lake City, UT
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de Araujo CV, Denorme F, Stephens WZ, Li Q, Cody MJ, Crandell JL, Petrey AC, Queisser KA, Rustad JL, Fulcher JM, Evangelista JL, Kay MS, Schiffman JD, Campbell RA, Yost CC. Corrigendum: Neonatal NET-Inhibitory Factor improves survival in the cecal ligation and puncture model of polymicrobial sepsis by inhibiting neutrophil extracellular traps. Front Immunol 2023; 14:1171222. [PMID: 37063850 PMCID: PMC10091279 DOI: 10.3389/fimmu.2023.1171222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 03/01/2023] [Indexed: 03/31/2023] Open
Abstract
[This corrects the article DOI: 10.3389/fimmu.2022.1046574.].
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Affiliation(s)
- Claudia V. de Araujo
- Department of Pediatrics/Neonatology, University of Utah, Salt Lake City, UT, United States
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - Frederik Denorme
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - W. Zac Stephens
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
| | - Qing Li
- High Throughput Genomics and Bioinformatic Analysis Shared Resource, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, United States
| | - Mark J. Cody
- Department of Pediatrics/Neonatology, University of Utah, Salt Lake City, UT, United States
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - Jacob L. Crandell
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - Aaron C. Petrey
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
| | - Kimberly A. Queisser
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
| | - John L. Rustad
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - James M. Fulcher
- Department of Biochemistry, University of Utah, Salt Lake City, UT, United States
| | - Judah L. Evangelista
- Department of Biochemistry, University of Utah, Salt Lake City, UT, United States
| | - Michael S. Kay
- Department of Biochemistry, University of Utah, Salt Lake City, UT, United States
| | - Joshua D. Schiffman
- Department of Pediatrics/Hematology-Oncology, University of Utah, Salt Lake City, UT, United States
- Peel Therapeutics, Inc., Salt Lake City, UT, United States
| | - Robert A. Campbell
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Christian C. Yost
- Department of Pediatrics/Neonatology, University of Utah, Salt Lake City, UT, United States
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
- *Correspondence: Christian C. Yost,
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Denorme F, Rustad JL, Portier I, Crandell JL, de Araujo CV, Cody MJ, Campbell RA, Yost CC. Neutrophil extracellular trap inhibition improves survival in neonatal mouse infectious peritonitis. Pediatr Res 2023; 93:862-869. [PMID: 35902703 PMCID: PMC9331023 DOI: 10.1038/s41390-022-02219-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 06/25/2022] [Accepted: 07/09/2022] [Indexed: 12/01/2022]
Abstract
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.
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Affiliation(s)
| | - John L Rustad
- Molecular Medicine Program, Salt Lake City, UT, 84112, USA
| | - Irina Portier
- Molecular Medicine Program, Salt Lake City, UT, 84112, USA
| | | | - Claudia V de Araujo
- Molecular Medicine Program, Salt Lake City, UT, 84112, USA
- Department of Pediatrics/Neonatology, Salt Lake City, UT, 84112, USA
| | - Mark J Cody
- Molecular Medicine Program, Salt Lake City, UT, 84112, USA
- Department of Pediatrics/Neonatology, Salt Lake City, UT, 84112, USA
| | - Robert A Campbell
- Molecular Medicine Program, Salt Lake City, UT, 84112, USA
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, 84112, USA
| | - Christian C Yost
- Molecular Medicine Program, Salt Lake City, UT, 84112, USA.
- Department of Pediatrics/Neonatology, Salt Lake City, UT, 84112, USA.
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de Araujo CV, Denorme F, Stephens WZ, Li Q, Cody MJ, Crandell JL, Petrey AC, Queisser KA, Rustad JL, Fulcher JM, Evangelista JL, Kay MS, Schiffman JD, Campbell RA, Yost CC. Neonatal NET-Inhibitory Factor improves survival in the cecal ligation and puncture model of polymicrobial sepsis by inhibiting neutrophil extracellular traps. Front Immunol 2023; 13:1046574. [PMID: 36733389 PMCID: PMC9888311 DOI: 10.3389/fimmu.2022.1046574] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/28/2022] [Indexed: 01/19/2023] Open
Abstract
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.
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Affiliation(s)
- Claudia V. de Araujo
- Department of Pediatrics/Neonatology, University of Utah, Salt Lake City, UT, United States
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - Frederik Denorme
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - W. Zac Stephens
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
| | - Qing Li
- High Throughput Genomics and Bioinformatic Analysis Shared Resource, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, United States
| | - Mark J. Cody
- Department of Pediatrics/Neonatology, University of Utah, Salt Lake City, UT, United States
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - Jacob L. Crandell
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - Aaron C. Petrey
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
| | - Kimberly A. Queisser
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
| | - John L. Rustad
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - James M. Fulcher
- Department of Biochemistry, University of Utah, Salt Lake City, UT, United States
| | - Judah L. Evangelista
- Department of Biochemistry, University of Utah, Salt Lake City, UT, United States
| | - Michael S. Kay
- Department of Biochemistry, University of Utah, Salt Lake City, UT, United States
| | - Joshua D. Schiffman
- Department of Pediatrics/Hematology-Oncology, University of Utah, Salt Lake City, UT, United States
- Peel Therapeutics, Inc., Salt Lake City, UT, United States
| | - Robert A. Campbell
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Christian C. Yost
- Department of Pediatrics/Neonatology, University of Utah, Salt Lake City, UT, United States
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
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Denorme F, Portier I, Rustad JL, Cody MJ, de Araujo CV, Hoki C, Alexander MD, Grandhi R, Dyer MR, Neal MD, Majersik JJ, Yost CC, Campbell RA. Neutrophil extracellular traps regulate ischemic stroke brain injury. J Clin Invest 2022; 132:154225. [PMID: 35358095 PMCID: PMC9106355 DOI: 10.1172/jci154225] [Citation(s) in RCA: 100] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 03/29/2022] [Indexed: 11/17/2022] Open
Abstract
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.
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Affiliation(s)
| | | | | | | | | | | | | | - Ramesh Grandhi
- Deparment of Radiology and Imaging Sciences, and,Department of Neurosurgery, University of Utah, Salt Lake City, Utah, USA
| | - Mitchell R. Dyer
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Matthew D. Neal
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | | | - Robert A. Campbell
- Molecular Medicine Program,,Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
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Denorme F, Portier I, Cody MJ, De Araujo CV, Rustad JP, Hoki C, Alexander MD, Grandhi R, Neal MD, Majersik JJ, Yost CC, Campbell R. Abstract 18: Targeting Neutrophil Extracellular Traps Improves Ischemic Stroke Outcomes. Stroke 2022. [DOI: 10.1161/str.53.suppl_1.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rationale:
Ischemic stroke prompts an inflammatory response which is associated with worse outcomes. Classic anti-inflammatory strategies were unsuccessful in clinical trials, implying other mechanisms contribute to injurious inflammation in stroke. In response to stimuli, neutrophils can release DNA web-like structures called neutrophil extracellular traps (NETs). Recently, a role for NETs in cardiovascular disease has emerged. Here, we studied whether NETs contribute to ischemic stroke outcomes.
Methods:
Markers of NET formation were assessed in brain tissue and plasma from ischemic stroke patients. For murine studies, we used male and female mice that were subjected to transient middle cerebral artery occlusion. Stroke outcomes were assessed 24 hours or 7 days after stroke.
Results:
NETs were found in brain tissue from deceased ischemic stroke patients. Ischemic stroke patients had significantly increased plasma biomarkers of NET formation including citrullinated histone H3 (p<0.0001) and MPO-DNA complexes (p<0.001) compared to matched controls. NET biomarkers positively correlated with worse stroke outcomes at discharge (p<0.05) while they did not correlate with stroke severity at admission. To target NET formation in ischemic stroke, we investigated the therapeutic potential of a recently discovered neonatal NET inhibitory factor (nNIF). nNIF specifically blocks NET formation in human and murine neutrophils without affecting other critical neutrophil functions. Mice prophylactically treated with nNIF had significantly reduced brain and plasma NETs after stroke while cerebral neutrophil recruitment remained unaffected. The reduction in NET formation was associated with significantly reduced neuronal apoptosis and smaller brain infarcts (p<0.0001). Furthermore, nNIF treated mice had improved neurological behavior and motor function, and enhanced 7-day survival after ischemic stroke (p<0.001). Importantly, these results were confirmed in diabetic mice and >18-month-old mice and nNIF was still effective when administered therapeutically, 1 hour after stroke onset.
Conclusions:
Our results support a pathological role for NETs in ischemic stroke and warrant further investigation into nNIF to improve stroke outcomes.
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Bhatlekar S, Jacob S, Manne BK, Guo L, Denorme F, Tugolukova EA, Cody MJ, Kosaka Y, Rigoutsos I, Campbell RA, Rowley JW, O'Connell RM, Bray PF. Megakaryocyte-specific knockout of the Mir-99b/let7e/125a cluster lowers platelet count without altering platelet function. Blood Cells Mol Dis 2021; 92:102624. [PMID: 34775219 PMCID: PMC8682963 DOI: 10.1016/j.bcmd.2021.102624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 11/02/2021] [Indexed: 12/11/2022]
Abstract
The purpose of this research was to assess the effects of a microRNA (miRNA) cluster on platelet production. Human chromosome 19q13.41 harbors an evolutionarily conserved cluster of three miRNA genes (MIR99B, MIRLET7E, MIR125A) within 727 base-pairs. We now report that levels of miR-99b-5p, miR-let7e-5p and miR-125a-5p are strongly correlated in human platelets, and all are positively associated with platelet count, but not white blood count or hemoglobin level. Although the cluster regulates hematopoietic stem cell proliferation, the function of this genomic locus in megakaryocyte (MK) differentiation and platelet production is unknown. Furthermore, studies of individual miRNAs do not represent broader effects in the context of a cluster. To address this possibility, MK/platelet lineage-specific Mir-99b/let7e/125a knockout mice were generated. Compared to wild type littermates, cluster knockout mice had significantly lower platelet counts and reduced MK proplatelet formation, but no differences in MK numbers, ploidy, maturation or ultra-structural morphology, and no differences in platelet function. Compared to wild type littermates, knockout mice showed similar survival after pulmonary embolism. The major conclusions are that the effect of the Mir-99b/let7e/125a cluster is confined to a late stage of thrombopoiesis, and this effect on platelet number is uncoupled from platelet function.
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Affiliation(s)
- Seema Bhatlekar
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Shancy Jacob
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Bhanu K Manne
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Li Guo
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Frederik Denorme
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Emilia A Tugolukova
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Mark J Cody
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Yasuhiro Kosaka
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Isidore Rigoutsos
- Computational Medicine Center, Thomas Jefferson University, 1020 Locust, Philadelphia, PA 19107, United States of America
| | - Robert A Campbell
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Jesse W Rowley
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America
| | - Ryan M O'Connell
- Division of Microbiology and Immunology, Department of Pathology, Huntsman Cancer Institute, University of Utah, 2000 Cir of Hope Dr, Salt Lake City, UT 84112, United States of America
| | - Paul F Bray
- Program in Molecular Medicine and Department of Internal Medicine, 15 North 2030 East, Bldg 533, University of Utah, Salt Lake City, UT 84112, United States of America; Division of Hematology and Hematologic Malignancies, Department of Internal Medicine, University of Utah, 2000 Cir of Hope Dr, Salt Lake City, UT 84112, United States of America.
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Campbell RA, Campbell HD, Bircher JS, de Araujo CV, Denorme F, Crandell JL, Rustad JL, Monts J, Cody MJ, Kosaka Y, Yost CC. Placental HTRA1 cleaves α1-antitrypsin to generate a NET-inhibitory peptide. Blood 2021; 138:977-988. [PMID: 34192300 PMCID: PMC9069473 DOI: 10.1182/blood.2020009021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 06/30/2021] [Accepted: 06/13/2021] [Indexed: 11/20/2022] Open
Abstract
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.
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Affiliation(s)
- Robert A Campbell
- University of Utah Molecular Medicine Program, Salt Lake City, UT; and
- Department of Internal Medicine
| | | | | | | | - Frederik Denorme
- University of Utah Molecular Medicine Program, Salt Lake City, UT; and
| | - Jacob L Crandell
- University of Utah Molecular Medicine Program, Salt Lake City, UT; and
| | - John L Rustad
- University of Utah Molecular Medicine Program, Salt Lake City, UT; and
| | - Josh Monts
- Flow Cytometry Core, University of Utah, Salt Lake City, UT
| | - Mark J Cody
- University of Utah Molecular Medicine Program, Salt Lake City, UT; and
- Department of Pediatrics, and
| | - Yasuhiro Kosaka
- University of Utah Molecular Medicine Program, Salt Lake City, UT; and
| | - Christian C Yost
- University of Utah Molecular Medicine Program, Salt Lake City, UT; and
- Department of Pediatrics, and
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Trivedi S, Grossmann AH, Jensen O, Cody MJ, Wahlig TA, Hayakawa Serpa P, Langelier C, Warren KJ, Yost CC, Leung DT. Intestinal Infection Is Associated With Impaired Lung Innate Immunity to Secondary Respiratory Infection. Open Forum Infect Dis 2021; 8:ofab237. [PMID: 34189172 PMCID: PMC8231398 DOI: 10.1093/ofid/ofab237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/05/2021] [Indexed: 11/23/2022] Open
Abstract
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.
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Affiliation(s)
- Shubhanshi Trivedi
- Division of Infectious Disease, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Allie H Grossmann
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, USA.,Division of Anatomic Pathology, Department of Pathology, University of Utah, Salt Lake City, Utah, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA
| | - Owen Jensen
- Division of Infectious Disease, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Mark J Cody
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Taylor A Wahlig
- Division of Infectious Disease, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Paula Hayakawa Serpa
- Chan Zuckerberg Biohub, San Francisco, California, USA.,Division of Infectious Diseases, Department of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Charles Langelier
- Chan Zuckerberg Biohub, San Francisco, California, USA.,Division of Infectious Diseases, Department of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Kristi J Warren
- Division of Pulmonary Medicine, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Christian C Yost
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA
| | - Daniel T Leung
- Division of Infectious Disease, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake City, Utah, USA
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10
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Bhatlekar S, Manne BK, Basak I, Edelstein LC, Tugolukova E, Stoller ML, Cody MJ, Morley SC, Nagalla S, Weyrich AS, Rowley JW, O'Connell RM, Rondina MT, Campbell RA, Bray PF. miR-125a-5p regulates megakaryocyte proplatelet formation via the actin-bundling protein L-plastin. Blood 2020; 136:1760-1772. [PMID: 32844999 PMCID: PMC7544541 DOI: 10.1182/blood.2020005230] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 05/24/2020] [Indexed: 12/17/2022] Open
Abstract
There is heritability to interindividual variation in platelet count, and better understanding of the regulating genetic factors may provide insights for thrombopoiesis. MicroRNAs (miRs) regulate gene expression in health and disease, and megakaryocytes (MKs) deficient in miRs have lower platelet counts, but information about the role of miRs in normal human MK and platelet production is limited. Using genome-wide miR profiling, we observed strong correlations among human bone marrow MKs, platelets, and differentiating cord blood-derived MK cultures, and identified MK miR-125a-5p as associated with human platelet number but not leukocyte or hemoglobin levels. Overexpression and knockdown studies showed that miR-125a-5p positively regulated human MK proplatelet (PP) formation in vitro. Inhibition of miR-125a-5p in vivo lowered murine platelet counts. Analyses of MK and platelet transcriptomes identified LCP1 as a miR-125a-5p target. LCP1 encodes the actin-bundling protein, L-plastin, not previously studied in MKs. We show that miR-125a-5p directly targets and reduces expression of MK L-plastin. Overexpression and knockdown studies show that L-plastin promotes MK progenitor migration, but negatively correlates with human platelet count and inhibits MK PP formation (PPF). This work provides the first evidence for the actin-bundling protein, L-plastin, as a regulator of human MK PPF via inhibition of the late-stage MK invagination system, podosome and PPF, and PP branching. We also provide resources of primary and differentiating MK transcriptomes and miRs associated with platelet counts. miR-125a-5p and L-plastin may be relevant targets for increasing in vitro platelet manufacturing and for managing quantitative platelet disorders.
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Affiliation(s)
- Seema Bhatlekar
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
| | - Bhanu K Manne
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
| | - Indranil Basak
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
| | - Leonard C Edelstein
- Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA
| | - Emilia Tugolukova
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
| | | | - Mark J Cody
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
| | - Sharon C Morley
- Division of Infectious Diseases, Department of Pediatrics and
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Srikanth Nagalla
- Division of Hematology and Oncology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
| | - Andrew S Weyrich
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
- Division of Pulmonary, Department of Internal Medicine
| | - Jesse W Rowley
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
- Division of Pulmonary, Department of Internal Medicine
| | - Ryan M O'Connell
- Division of Microbiology and Immunology, Department of Pathology, and
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT
| | - Matthew T Rondina
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
- Geriatric Research, Education and Clinical Center, George E. Wahlen VAMC GRECC, Salt Lake City, UT; and
- Division of General Internal Medicine and
| | - Robert A Campbell
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
- Division of General Internal Medicine and
| | - Paul F Bray
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT
- Division of Hematology and Hematologic Malignancies, Department of Internal Medicine, University of Utah, Salt Lake City, UT
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Campbell RA, Cody MJ, Manne BK, Zimmerman GA, Yost CC. Interleukin 6 receptor alpha expression in PMNs isolated from prematurely born neonates: decreased expression is associated with differential mTOR signaling. Pediatr Res 2019; 86:55-62. [PMID: 30965356 PMCID: PMC6594868 DOI: 10.1038/s41390-019-0388-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/15/2019] [Accepted: 03/27/2019] [Indexed: 11/09/2022]
Abstract
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.
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Affiliation(s)
- Robert A. Campbell
- Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Mark J. Cody
- Department of Pediatrics/Neonatology, University of Utah, Salt Lake City, Utah, USA
| | - Bhanu K. Manne
- Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Guy A. Zimmerman
- Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Christian C. Yost
- Department of Pediatrics/Neonatology, University of Utah, Salt Lake City, Utah, USA,Program in Molecular Medicine, University of Utah, Salt Lake City, Utah, USA,Corresponding Author: Christian Con Yost, MD, Department of Pediatrics/Neonatology, University of Utah School of Medicine, Williams Building, 295 Chipeta Way, Salt Lake City, UT 84108, Phone: 801-581-7052; Fax: 801-585-7395,
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Yost CC, Schwertz H, Cody MJ, Wallace JA, Campbell RA, Vieira-de-Abreu A, Araujo CV, Schubert S, Harris ES, Rowley JW, Rondina MT, Fulcher JM, Koening CL, Weyrich AS, Zimmerman GA. Neonatal NET-inhibitory factor and related peptides inhibit neutrophil extracellular trap formation. J Clin Invest 2016; 126:3783-3798. [PMID: 27599294 DOI: 10.1172/jci83873] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 07/28/2016] [Indexed: 12/22/2022] Open
Abstract
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.
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Glenn JW, Cody MJ, McManus MP, Pulsipher MA, Schiffman JD, Yost CC. Deficient Neutrophil Extracellular Trap Formation in Patients Undergoing Bone Marrow Transplantation. Front Immunol 2016; 7:250. [PMID: 27446080 PMCID: PMC4921458 DOI: 10.3389/fimmu.2016.00250] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 06/13/2016] [Indexed: 01/10/2023] Open
Abstract
Overwhelming infection causes significant morbidity and mortality among patients treated with bone marrow transplantation (BMT) for primary immune deficiencies, syndromes of bone marrow failure, or cancer. The polymorphonuclear leukocyte (PMN; neutrophil) is the first responder to microbial invasion and acts within the innate immune system to contain and clear infections. PMNs contain, and possibly clear, infections in part by forming neutrophil extracellular traps (NETs). NETs are extensive lattices of extracellular DNA and decondensed chromatin decorated with antimicrobial proteins and degradative enzymes, such as histones, myeloperoxidase, and neutrophil elastase. They trap and contain microbes, including bacteria and fungi, and may directly affect extracellular microbial killing. Whether or not deficient NET formation contributes to the increased risk for overwhelming infection in patients undergoing BMT remains incompletely characterized, especially in the pediatric population. We examined NET formation in vitro in PMNs isolated from 24 patients who had undergone BMT for 13 different clinical indications. For these 24 study participants, the median age was 7 years. For 6 of the 24 patients, we examined NET formation by PMNs isolated from serial, peripheral blood samples drawn at three different clinical time points: pre-BMT, pre-engraftment, and post-engraftment. We found decreased NET formation by PMNs isolated from patients prior to BMT and during the pre-engraftment and post-engraftment phases, with decreased NET formation compared with healthy control PMNs detected even out to 199 days after their BMT. This decrease in NET formation after BMT did not result from neutrophil developmental immaturity as we demonstrated that >80% of the PMNs tested using flow cytometry expressed both CD10 and CD16 as markers of terminal differentiation along the neutrophilic lineage. These pilot study results mandate further exploration regarding the mechanisms or factors regulating NET formation by PMNs in patients at risk for overwhelming infection following BMT.
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Affiliation(s)
- Jared W Glenn
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine , Salt Lake City, UT , USA
| | - Mark J Cody
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine , Salt Lake City, UT , USA
| | - Meghann P McManus
- Division of Pediatric Hematology, Oncology, and Bone Marrow Transplant, Department of Pediatrics, University of Utah School of Medicine , Salt Lake City, UT , USA
| | - Michael A Pulsipher
- Division of Pediatric Hematology, Oncology, and Bone Marrow Transplant, Department of Pediatrics, University of Utah School of Medicine , Salt Lake City, UT , USA
| | - Joshua D Schiffman
- Division of Pediatric Hematology, Oncology, and Bone Marrow Transplant, Department of Pediatrics, University of Utah School of Medicine , Salt Lake City, UT , USA
| | - Christian Con Yost
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine , Salt Lake City, UT , USA
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Thornton NL, Cody MJ, Yost CC. Toll-like receptor 1/2 stimulation induces elevated interleukin-8 secretion in polymorphonuclear leukocytes isolated from preterm and term newborn infants. Neonatology 2012; 101:140-6. [PMID: 21952587 PMCID: PMC3223067 DOI: 10.1159/000330567] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 07/01/2011] [Indexed: 01/09/2023]
Abstract
BACKGROUND Neonatal neutrophil dysfunction contributes to inflammatory tissue damage in newborn infants. Toll-like receptors (TLRs) activate the innate immune response through recognition of pathogen-associated molecular patterns. Expression and function of TLRs by neonatal neutrophils has not well been characterized. OBJECTIVE We hypothesized that, compared to polymorphonuclear leukocytes (PMNs) isolated from adults, neonatal PMNs isolated from either term or preterm infants express and release different levels of inflammatory cytokines and chemokines in response to stimulation with TLR1-9 agonists. METHODS We stimulated PMNs isolated from preterm (n = 12) and term (n = 10) infants as well as adults (n = 10) with agonists recognized by TLRs1-9 and quantified chemokine and cytokine expression and secretion by ELISA and Luminex® multiplex quantification assay. RESULTS Neonatal and adult PMNs stimulated with agonists recognized by TLRs1-9 differentially secrete inflammatory products. Signaling via TLR2 heterodimers is a potent mechanism for release of interleukin-8, a critical proinflammatory chemokine, by neonatal PMNs--a previously unrecognized facet of neonatal inflammation. Following TLR1/2 (PAM3CSK4) stimulation, interleukin-8 secretion by neonatal PMNs, whether term or preterm, substantially exceeds that of adult PMNs assayed in parallel. CONCLUSIONS These studies provide new insights relevant to the inflammatory biology of neonates, both term and preterm, and implicate exaggerated PMN recruitment in neonatal syndromes of dysregulated inflammation such as necrotizing enterocolitis or neonatal chronic lung disease.
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Affiliation(s)
- Nathan L Thornton
- Department of Pediatrics and Program in Human Molecular Biology and Genetics, University of Utah, Salt Lake City, Utah 84108, USA
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Kraemer BF, Campbell RA, Schwertz H, Cody MJ, Franks Z, Tolley ND, Kahr WHA, Lindemann S, Seizer P, Yost CC, Zimmerman GA, Weyrich AS. Novel anti-bacterial activities of β-defensin 1 in human platelets: suppression of pathogen growth and signaling of neutrophil extracellular trap formation. PLoS Pathog 2011; 7:e1002355. [PMID: 22102811 PMCID: PMC3213094 DOI: 10.1371/journal.ppat.1002355] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 09/20/2011] [Indexed: 12/11/2022] Open
Abstract
Human β-defensins (hBD) are antimicrobial peptides that curb microbial activity. Although hBD's are primarily expressed by epithelial cells, we show that human platelets express hBD-1 that has both predicted and novel antibacterial activities. We observed that activated platelets surround Staphylococcus aureus (S. aureus), forcing the pathogens into clusters that have a reduced growth rate compared to S. aureus alone. Given the microbicidal activity of β-defensins, we determined whether hBD family members were present in platelets and found mRNA and protein for hBD-1. We also established that hBD-1 protein resided in extragranular cytoplasmic compartments of platelets. Consistent with this localization pattern, agonists that elicit granular secretion by platelets did not readily induce hBD-1 release. Nevertheless, platelets released hBD-1 when they were stimulated by α-toxin, a S. aureus product that permeabilizes target cells. Platelet-derived hBD-1 significantly impaired the growth of clinical strains of S. aureus. hBD-1 also induced robust neutrophil extracellular trap (NET) formation by target polymorphonuclear leukocytes (PMNs), which is a novel antimicrobial function of β-defensins that was not previously identified. Taken together, these data demonstrate that hBD-1 is a previously-unrecognized component of platelets that displays classic antimicrobial activity and, in addition, signals PMNs to extrude DNA lattices that capture and kill bacteria. Platelets are small cells in the bloodstream whose primary function is to stop bleeding. In addition to their clotting functions, we show that human platelets stall bacterial growth. This inhibitory property of platelets is due to β-defensin 1, a small antimicrobial protein that kills bacteria. β-defensin 1 also induces white blood cells to discharge spider-like webs that trap and kill bacteria. Together, these findings indicate that human platelets use β-defensin 1 to fight off bacterial infection.
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Affiliation(s)
- Bjoern F. Kraemer
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
- Medizinische Klinik III, Universitaetsklinikum Tuebingen, Tuebingen, Germany
| | - Robert A. Campbell
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
| | - Hansjörg Schwertz
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
- Department of Surgery, University of Utah, Salt Lake City, Utah, United States of America
| | - Mark J. Cody
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
| | - Zechariah Franks
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
| | - Neal D. Tolley
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
| | - Walter H. A. Kahr
- Division of Haematology/Oncology, Program in Cell Biology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Ontario, Canada
| | | | - Peter Seizer
- Medizinische Klinik III, Universitaetsklinikum Tuebingen, Tuebingen, Germany
| | - Christian C. Yost
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, United States of America
- Department of Pediatrics, University of Utah, Salt Lake City, Utah, United States of America
| | - Guy A. Zimmerman
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States of America
| | - Andrew S. Weyrich
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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Hannon JD, Cody MJ, Sun DX, Housmans PR. Effects of isoflurane and sevoflurane on intracellular calcium and contractility in pressure-overload hypertrophy. Anesthesiology 2004; 101:675-86. [PMID: 15329592 DOI: 10.1097/00000542-200409000-00016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Depression of myocardial contractility as a result of isoflurane appears to be greater in myocardial hypertrophy, and the cellular basis for this difference in susceptibility is not clear. In this study we examined the effects of isoflurane and sevoflurane on contractility and intracellular calcium in an animal model of pressure-overload hypertrophy. METHODS Pressure-overload hypertrophy was established in young male ferrets by banding the main pulmonary artery for 1 month and the effects of isoflurane and sevoflurane on contractility and intracellular calcium ([Ca]i) were examined in isolated right ventricular papillary muscles, trabeculae, and myocytes. Intracellular calcium was measured with the bioluminescent photoprotein aequorin in isolated papillary muscles, and also with the fluorescent indicator fluo-3 in isolated ventricular myocytes. In addition, Ca sensitivity was assessed in isolated trabeculae after disruption of the surface membrane with a nonionic detergent (skinned fibers). RESULTS In the presence of isoflurane and sevoflurane, papillary muscles from banded animals exhibited a greater depression of contractility and isolated ventricular myocytes showed a greater decrease in peak [Ca]i. Furthermore, baseline calcium sensitivity was decreased and the slope of the relationship between [Ca] and force was increased in skinned trabeculae from banded animals. Isoflurane decreased calcium sensitivity in trabeculae from both normal and banded animals. CONCLUSIONS These results suggest that changes in [Ca]i and altered calcium sensitivity are both responsible for the exaggerated effects of some volatile anesthetics on contractility in pressure-overload hypertrophy.
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Affiliation(s)
- James D Hannon
- Department of Anesthesiology, Mayo Foundation, Rochester, Minnesota 55905, USA.
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Abstract
In the present study, we tested the hypothesis that intrinsic differences in ATP consumption rate per cross bridge exist across rat diaphragm muscle (Dia(m)) fibers expressing different myosin heavy chain (MHC) isoforms. During maximum Ca(2+) activation (pCa 4.0) of single, Triton X-permeabilized Dia(m) fibers, isometric ATP consumption rate was determined by using an NADH-linked fluorometric technique. The MHC concentration in single Dia(m) fibers was determined by densitometric analysis of SDS-PAGE gels and comparison to a standard curve of known MHC concentrations. Isometric ATP consumption rate varied across Dia(m) fibers expressing different MHC isoforms, being highest in fibers expressing MHC(2X) (1.14 +/- 0.08 nmol. mm(-3). s(-1)) and/or MHC(2B) (1.33 +/- 0.08 nmol. mm(-3). s(-1)), followed by fibers expressing MHC(2A) (0.77 +/- 0.11 nmol. mm(-3). s(-1)) and MHC(Slow) (0.46 +/- 0.03 nmol. mm(-3). s(-1)). These differences in ATP consumption rate also persisted when it was normalized for MHC concentration in single Dia(m) fibers. Normalized ATP consumption rate for MHC concentration varied across Dia(m) fibers expressing different MHC isoforms, being highest in fibers expressing MHC(2X) (2.02 +/- 0.19 s(-1)) and/or MHC(2B) (2.64 +/- 0.15 s(-1)), followed by fibers expressing MHC(2A) (1.57 +/- 0.16 s(-1)) and MHC(Slow) (0.77 +/- 0.05 s(-1)). On the basis of these results, we conclude that there are intrinsic differences in ATP consumption rate per cross bridge in Dia(m) fibers expressing MHC isoforms.
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Affiliation(s)
- Young-Soo Han
- Department of Anesthesiology, Mayo Medical School, Rochester, Minnesota 55905, USA
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Abstract
OBJECTIVES To examine the ease with which underage smokers can purchase cigarettes online using money orders and to evaluate the effectiveness of internet filtering programs in blocking access to internet cigarette vendors (ICVs). DESIGN Four young people purchased 32 money orders using 32 different names to buy one carton of cigarettes for each named individual. Each money order was subsequently mailed to a different ICV in the USA. No age related information accompanied these online orders. Two internet filtering programs ("Bess" and filtertobacco.org) were tested for their relative efficacy in blocking access to ICV sites. RESULTS Of the 32 orders placed, four orders never reached the intended ICV. Of the remaining 28 orders, 20 (71%) were filled despite a lack of age verification. Only four (14%) of the orders received were rejected because they lacked proof of age. "Bess" blocked access to 84% and filtertobacco.org to 94% of the ICV sites. CONCLUSIONS Although underage smokers can easily purchase cigarettes online using money orders, access to these sites can be largely blocked if appropriate filtering devices are installed.
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Affiliation(s)
- J A Bryant
- School of Communication, Annenberg School for Communication, University of Southern California, Los Angeles, California 90089-0281, USA
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Abstract
BACKGROUND The surface membrane Ca(2+)-adenosine triphosphatase and Na(+)-Ca(2+) exchanger transport Ca(2+) out of the ventricular myocyte, competing for cytosolic Ca(2+) with the Ca(2+)-adenosine triphosphatase located in the sarcoplasmic reticulum. In this study the authors examined the effects of halothane, isoflurane, and sevoflurane on Ca(2+) extrusion from the cell and sarcoplasmic reticulum Ca(2+) content. METHODS Single myocytes from the right ventricular free wall of adult male ferret hearts were isolated, loaded with the acetoxymethyl ester of the fluorescent Ca(2+) indicator fluo-3, and electrically stimulated at 0.25 Hz to reach a steady state level of intracellular Ca(2+) stores. The effects of halothane, isoflurane, and sevoflurane (1 minimum alveolar concentration) on the peak and rate of decline of the Ca(2+) transient induced by 10 mm caffeine were examined. The peak was used as an index of sarcoplasmic reticulum Ca(2+) content, and the rate of decline was used to monitor Ca(2+) extrusion from the cell. RESULTS During control conditions, halothane reduced the Ca(2+) content of the sarcoplasmic reticulum, isoflurane maintained it, and sevoflurane caused it to increase. Halothane did not affect Ca(2+) extrusion from the cell, but both isoflurane and sevoflurane inhibited it. When Na(+)-Ca(2+) exchange was inhibited by ionic substitution, isoflurane and sevoflurane still reduced the rate of Ca(2+) efflux from the cell. However, when the sarcolemmal Ca(2+)-adenosine triphosphatase was inhibited by carboxyeosin, isoflurane and sevoflurane had no effect on Ca(2+) efflux. CONCLUSIONS These results suggest that isoflurane and sevoflurane inhibit Ca(2+) transport from the cell via the sarcolemmal Ca(2+)-adenosine triphosphatase. This effect seems to counteract the decrease in Ca(2+) influx through sarcolemmal L-type Ca(2+) channels and maintains sarcoplasmic reticulum Ca(2+) stores.
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Affiliation(s)
- James D Hannon
- Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
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Abstract
We hypothesized that 1) hypothyroidism (Hyp) decreases myosin heavy chain (MHC) content per half-sarcomere in diaphragm muscle (Dia(m)) fibers, 2) Hyp decreases the maximum specific force (F(max)) of Dia(m) fibers because of the reduction in MHC content per half-sarcomere, and 3) Hyp affects MHC content per half-sarcomere and F(max) to a greater extent in fibers expressing MHC type 2X (MHC(2X)) and/or MHC type 2B (MHC(2B)). Studies were performed on single Triton X-permeabilized fibers activated at pCa 4.0. MHC content per half-sarcomere was determined by densitometric analysis of SDS-polyacrylamide gels and comparison with a standard curve of known MHC concentrations. After 3 wk of Hyp, MHC content per half-sarcomere was reduced in fibers expressing MHC(2X) and/or MHC(2B). On the basis of electron-microscopic analysis, this reduction in MHC content was also reflected by a decrease in myofibrillar volume density and thick filament density. Hyp decreased F(max) across all MHC isoforms; however, the greatest decrease occurred in fibers expressing fast MHC isoforms (approximately 40 vs. approximately 20% for fibers expressing slow MHC isoforms). When normalized for MHC content per half-sarcomere, force generated by Hyp fibers expressing MHC(2A) was reduced compared with control fibers, whereas force per half-sarcomere MHC content was higher for fibers expressing MHC(2X) and/or MHC(2B) in the Hyp Dia(m) than for controls. These results indicate that the effect of Hyp is more pronounced on fibers expressing MHC(2X) and/or MHC(2B) and that the reduction of F(max) with Hyp may be at least partially attributed to a decrease in MHC content per half-sarcomere but not to changes in force per cross bridge.
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Affiliation(s)
- Paige C Geiger
- Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
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Heunks LM, Cody MJ, Geiger PC, Dekhuijzen PN, Sieck GC. Nitric oxide impairs Ca2+ activation and slows cross-bridge cycling kinetics in skeletal muscle. J Appl Physiol (1985) 2001; 91:2233-9. [PMID: 11641366 DOI: 10.1152/jappl.2001.91.5.2233] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of the nitric oxide (NO) donor spermine NONOate (Sp-NO, 1.0 mM) on cross-bridge recruitment and cross-bridge cycling kinetics were studied in permeabilized rabbit psoas muscle fibers. Fibers were activated at various Ca2+ concentrations (pCa, negative logarithm of Ca2+ concentration), and the pCa at which force was maximal (pCa 4.0) and approximately 50% of maximal (pCa50 5.6) were determined. Fiber stiffness was determined using 1-kHz sinusoidal length perturbations, and the fraction of cross bridges in the force-generating state was estimated by the ratio of stiffness during maximal (pCa 4.0) and submaximal (pCa 5.6) Ca2+ activation to stiffness during rigor (at pCa 4.0). Cross-bridge cycling kinetics were evaluated by measuring the rate constant for force redevelopment after quick release (by 15% of optimal fiber length, L(o)) and restretch of the fiber to L(o). Exposing fibers to Sp-NO for 10 min reduced force and the fraction of cross bridges in the force-generating state at maximal and submaximal (pCa50) Ca2+ activation. However, the effects of Sp-NO were more pronounced during submaximal Ca2+ activation. Sp-NO also reduced the rate constant for force redevelopment but only during submaximal Ca2+ activation. We conclude that Sp-NO reduces Ca2+ sensitivity by decreasing the number of cross bridges in the strongly bound state and also impairs cross-bridge cycling kinetics during submaximal activation.
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Affiliation(s)
- L M Heunks
- Department of Pulmonary Diseases, University Hospital Nijmegen, 6500 HB Nijmegen, The Netherlands
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Abstract
BACKGROUND Isoflurane depresses the intracellular Ca2+ transient and force development during a twitch, but its effects on crossbridge cycling rates are difficult to predict because of the transient nature of the twitch. Measurements of the effects of isoflurane on crossbridge cycling kinetics during tetanic contractions, which provide a steady state level of activation in intact cardiac muscle, have not been previously reported. METHODS Ferret right ventricular papillary muscles were isolated, and superficial cells were microinjected with the bioluminescent photoprotein aequorin to monitor the intracellular Ca2+ concentration. The rate of tension redevelopment (kTR) was measured during steady state isometric activation (tetanic stimulation, frequency 20 Hz, 1 microM ryanodine, temperature = 30 degrees C) in the absence of isoflurane (2, 6, and 12 mM extracellular [Ca2+]) and in the presence of 0.5, 1.0, and 1.5 minimum alveolar concentration isoflurane (12 mM extracellular [Ca2+]). RESULTS Intracellular [Ca2+], isometric force, and kTR all increased when the extracellular [Ca2+] increased. Isoflurane (0.5, 1.0, and 1.5 minimum alveolar concentration) caused intracellular [Ca2+], isometric force, and kTR to decrease in a dose-dependent manner in the presence of 12 mM extracellular [Ca2+]. In the presence of increasing concentrations of isoflurane, the relation between intracellular [Ca2+] and force remained unchanged, whereas the relation between intracellular [Ca2+] and kTR was shifted toward higher [Ca2+]. CONCLUSIONS These results indicate that isoflurane depresses myocardial crossbridge cycling rates. It appears that this effect is partially mediated by a decrease in the intracellular [Ca2+]. However, additional mechanisms must be considered to explain the shift of the relation between intracellular [Ca2+] and kTR toward higher [Ca2+].
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Affiliation(s)
- J D Hannon
- Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
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24
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Geiger PC, Cody MJ, Macken RL, Bayrd ME, Sieck GC. Effect of unilateral denervation on maximum specific force in rat diaphragm muscle fibers. J Appl Physiol (1985) 2001; 90:1196-204. [PMID: 11247914 DOI: 10.1152/jappl.2001.90.4.1196] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We hypothesize that 1) the effect of denervation (DNV) is more pronounced in fibers expressing fast myosin heavy chain (MHC) isoforms and 2) the effect of DNV on maximum specific force reflects a reduction in MHC content per half sarcomere or the number of cross bridges in parallel. Studies were performed on single Triton X-100-permeabilized fibers activated at a pCa (-log Ca2+ concentration) of 4.0. MHC content per half sarcomere was determined by densitometric analysis of SDS-PAGE gels and comparison to a standard curve of known MHC concentrations. After 2 of wk DNV, the maximum specific force of fibers expressing MHC2X was reduced by approximately 40% (MHC(2B) expression was absent), whereas the maximum specific force of fibers expressing MHC2A and MHC(slow) decreased by only approximately 20%. DNV also reduced the MHC content in fibers expressing MHC2X, with no effect on fibers expressing MHC2A and MHC(slow). When normalized for MHC content per half sarcomere, force generated by DNV fibers expressing MHC2X and MHC2A was decreased compared with control fibers. These results suggest the force per cross bridge is also affected by DNV.
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Affiliation(s)
- P C Geiger
- Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
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25
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Hirschfeld M, Weis JJ, Toshchakov V, Salkowski CA, Cody MJ, Ward DC, Qureshi N, Michalek SM, Vogel SN. Signaling by toll-like receptor 2 and 4 agonists results in differential gene expression in murine macrophages. Infect Immun 2001; 69:1477-82. [PMID: 11179315 PMCID: PMC98044 DOI: 10.1128/iai.69.3.1477-1482.2001] [Citation(s) in RCA: 501] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Lipopolysaccharide (LPS) derived from the periodontal pathogen Porphyromonas gingivalis has been reported to differ structurally and functionally from enterobacterial LPS. These studies demonstrate that in contrast to protein-free enterobacterial LPS, a similarly purified preparation of P. gingivalis LPS exhibited potent Toll-like receptor 2 (TLR2), rather than TLR4, agonist activity to elicit gene expression and cytokine secretion in murine macrophages and transfectants. More importantly, TLR2 stimulation by this P. gingivalis LPS preparation resulted in differential expression of a panel of genes that are normally induced in murine macrophages by Escherichia coli LPS. These data suggest that (i) P. gingivalis LPS does not signal through TLR4 and (ii) signaling through TLR2 and through TLR4 differs quantitatively and qualitatively. Our data support the hypothesis that the shared signaling pathways elicited by TLR2 and by TLR4 agonists must diverge in order to account for the distinct patterns of inflammatory gene expression.
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Affiliation(s)
- M Hirschfeld
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, USA
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26
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Geiger PC, Cody MJ, Macken RL, Bayrd ME, Fang YH, Sieck GC. Mechanisms underlying increased force generation by rat diaphragm muscle fibers during development. J Appl Physiol (1985) 2001; 90:380-8. [PMID: 11133931 DOI: 10.1152/jappl.2001.90.1.380] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It has been found that maximum specific force (F(max); force per cross-sectional area) of rat diaphragm muscle doubles from birth to 84 days (adult). We hypothesize that this developmental change in F(max) reflects an increase in myosin heavy chain (MHC) content per half-sarcomere (an estimate of the number of cross bridges in parallel) and/or a greater force per cross bridge in fibers expressing fast MHC isoforms compared with slow and neonatal MHC isoforms (MHC(slow) and MHC(neo), respectively). Single Triton 100-X-permeabilized fibers were activated at a pCa of 4.0. MHC isoform expression was determined by SDS-PAGE. MHC content per half-sarcomere was determined by densitometric analysis and comparison to a standard curve of known MHC concentrations. MHC content per half-sarcomere progressively increased during early postnatal development. When normalized for MHC content per half-sarcomere, fibers expressing MHC(slow) and coexpressing MHC(neo) produced less force than fibers expressing fast MHC isoforms. We conclude that lower force per cross bridge in fibers expressing MHC(slow) and MHC(neo) contributes to the lower F(max) seen in early postnatal development.
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Affiliation(s)
- P C Geiger
- Department of Physiology and Biophysics, Rochester, Minnesota 55905, USA
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27
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Salkowski CA, Thomas KE, Cody MJ, Vogel SN. Impaired IFN-gamma production in IFN regulatory factor-1 knockout mice during endotoxemia is secondary to a loss of both IL-12 and IL-12 receptor expression. J Immunol 2000; 165:3970-7. [PMID: 11034406 DOI: 10.4049/jimmunol.165.7.3970] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mice with a targeted mutation in the gene that encodes the transcription factor IFN regulatory factor-1 (IRF-1) were used to assess the contribution of IRF-1 to IL-12-dependent and IL-12-independent pathways of IFN-gamma production. In response to LPS, IRF. 1-/- mice produced less IL-12 p40, IL-12 p35, and IFN-gamma mRNA in the liver than IRF-1+/+ mice. While pulmonary IFN-gamma mRNA levels were also mitigated in IRF-1-/- mice, pulmonary IL-12 p40 and IL-12 p35 mRNA were not dysregulated. Circulating IL-12 p70 and IFN-gamma levels were profoundly attenuated in LPS-challenged IRF-1-/- mice. Further analysis revealed a major deficiency in hepatic IL-12Rbeta1 and IL-12Rbeta2 mRNA expression as well as pulmonary IL-12Rbeta1 mRNA expression in LPS-challenged IRF-1-/- mice. In vitro, IFN-gamma up-regulated IL-12Rbeta1 mRNA in macrophages from IRF-1+/+, but not IRF-1-/-, mice. IFN-gamma-induced IL-12Rbeta2 mRNA expression was also diminished in macrophages from IRF-1-/- mice. In contrast to IRF-1+/+ mice, administration of exogenous IL-12 to IRF-1-/- mice resulted in reduced serum IFN-gamma and hepatic and pulmonary IFN-gamma mRNA, demonstrating that loss of IL-12R results in diminished IL-12 responsiveness. While LPS-challenged IRF-1-/- mice also had reduced IL-15 mRNA levels, serum IL-18 responses were intact. Finally, induction of IRF-1 mRNA by LPS in livers of IFN-gamma knockout mice were markedly attenuated, suggesting a feedback amplification loop. These studies indicate that IRF-1 deficiency disrupts both IL-12-dependent and -independent pathways of IFN-gamma production and that IRF-1 is a critical transcription factor involved in the regulation of not only IL-12, but also IL-12R.
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MESH Headings
- Animals
- Cells, Cultured
- DNA-Binding Proteins/biosynthesis
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/physiology
- Endotoxemia/genetics
- Endotoxemia/immunology
- Endotoxemia/metabolism
- Immunologic Deficiency Syndromes/genetics
- Immunologic Deficiency Syndromes/immunology
- Injections, Intraperitoneal
- Interferon Regulatory Factor-1
- Interferon-gamma/antagonists & inhibitors
- Interferon-gamma/biosynthesis
- Interferon-gamma/physiology
- Interleukin-12/administration & dosage
- Interleukin-12/antagonists & inhibitors
- Interleukin-12/biosynthesis
- Interleukin-15/antagonists & inhibitors
- Interleukin-15/biosynthesis
- Interleukin-15/genetics
- Lipopolysaccharides/administration & dosage
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphoproteins/biosynthesis
- Phosphoproteins/deficiency
- Phosphoproteins/genetics
- Phosphoproteins/physiology
- RNA, Messenger/biosynthesis
- Receptors, Interleukin/antagonists & inhibitors
- Receptors, Interleukin/biosynthesis
- Receptors, Interleukin/genetics
- Receptors, Interleukin-12
- Transcription Factors/biosynthesis
- Transcription Factors/deficiency
- Transcription Factors/genetics
- Transcription Factors/physiology
- Up-Regulation/genetics
- Up-Regulation/immunology
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Affiliation(s)
- C A Salkowski
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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28
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Abstract
In the present study, myosin heavy chain (MHC) content per half sarcomere, an estimate of the number of cross bridges available for force generation, was determined in rat diaphragm muscle (Dia(m)) fibers expressing different MHC isoforms. We hypothesize that fiber-type differences in maximum specific force [force per cross-sectional area (CSA)] reflect the number of cross bridges present per CSA. Studies were performed on single, Triton X-100-permeabilized rat Dia(m) fibers. Maximum specific force was determined by activation of single Dia(m) fibers in the presence of a high-calcium solution (pCa, -log Ca(2+) concentration of 4.0). SDS-PAGE and Western blot analyses were used to determine MHC isoform composition and MHC content per half sarcomere. Differences in maximum specific force across fast MHC isoforms were eliminated when controlled for half-sarcomere MHC content. However, the force produced by slow fibers remained below that of fast fibers when normalized for the number of cross bridges available. On the basis of these results, the lower force produced by slow fibers may be due to less force per cross bridge compared with fast fibers.
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Affiliation(s)
- P C Geiger
- Departments of Anesthesiology and of Physiology and Biophysics, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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29
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Prakash YS, Cody MJ, Hannon JD, Housmans PR, Sieck GC. Comparison of volatile anesthetic effects on actin-myosin cross-bridge cycling in neonatal versus adult cardiac muscle. Anesthesiology 2000; 92:1114-25. [PMID: 10754632 DOI: 10.1097/00000542-200004000-00030] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The neonatal myocardium is more sensitive to volatile anesthetics compared with adults. The greater myocardial sensitivity of neonates may be attributable to greater anesthetic effect on force regulation at the level of the cross-bridge. In the current study, the authors compared the effects of 1 and 2 minimum alveolar concentration (MAC) halothane and sevoflurane on cardiac muscle from 0- to 3-day-old (neonate) and 84-day-old (adult) rats. METHODS Triton X-100-skinned muscle strips were maximally activated at pCa (negative logarithm of the Ca2+ concentration) of 4.0, and the following were measured in the presence or absence of anesthetic: Rate of force redevelopment after rapid shortening and restretching (ktr) and isometric stiffness at maximal activation and in rigor. The fraction of attached cross-bridges (alphafs) and apparent rate constants for cross-bridge attachment (fapp) and detachment (gapp) were calculated assuming a two-state model for cross-bridge cycling. Anesthetic-induced changes in the mean stiffness per cross-bridge were also estimated from values in rigor versus maximum activation in the presence or absence of anesthetic. RESULTS Neonatal cardiac muscle displayed significantly smaller alphafs slower ktr and slower fapp compared with adult cardiac muscle; however, gapp was not significantly different. Halothane, and sevoflurane to a significantly lesser extent, decreased alphafs, fapp, and the mean force per cross-bridge and increased gapp to a greater extent in neonates. CONCLUSIONS These data indicate that weaker force production in neonatal cardiac muscle involves, at least in part, less efficient cross-bridge cycling kinetics. The authors conclude that the greater myocardial sensitivity of neonates to volatile anesthetics reflects, at least in part, a direct inhibition of cross-bridge cycling, especially the rates of cross-bridge attachment and detachment.
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Affiliation(s)
- Y S Prakash
- Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
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30
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Geiger PC, Cody MJ, Sieck GC. Force-calcium relationship depends on myosin heavy chain and troponin isoforms in rat diaphragm muscle fibers. J Appl Physiol (1985) 1999; 87:1894-900. [PMID: 10562634 DOI: 10.1152/jappl.1999.87.5.1894] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study examined Ca(2+) sensitivity of diaphragm muscle (Dia(m)) fibers expressing different myosin heavy chain (MHC) isoforms. We hypothesized that Dia(m) fibers expressing the MHC(slow) isoform have greater Ca(2+) sensitivity than fibers expressing fast MHC isoforms and that this fiber-type difference in Ca(2+) sensitivity reflects the isoform composition of the troponin (Tn) complex (TnC, TnT, and TnI). Studies were performed in single Triton-X-permeabilized Dia(m) fibers. The Ca(2+) concentration at which 50% maximal force was generated (pCa(50)) was determined for each fiber. SDS-PAGE and Western analyses were used to determine the MHC and Tn isoform composition of single fibers. The pCa(50) for Dia(m) fibers expressing MHC(slow) was significantly greater than that of fibers expressing fast MHC isoforms, and this greater Ca(2+) sensitivity was associated with expression of slow isoforms of the Tn complex. However, some Dia(m) fibers expressing MHC(slow) contained the fast TnC isoform. These results suggest that the combination of TnT, TnI, and TnC isoforms may determine Ca(2+) sensitivity in Dia(m) fibers.
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Affiliation(s)
- P C Geiger
- Departments of Anesthesiology and Physiology and Biophysics, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
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31
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Prakash YS, Cody MJ, Housmans PR, Hannon JD, Sieck GC. Comparison of cross-bridge cycling kinetics in neonatal vs. adult rat ventricular muscle. J Muscle Res Cell Motil 1999; 20:717-23. [PMID: 10672520 DOI: 10.1023/a:1005585807179] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The developmental shift in contractile protein isoform expression in the rodent heart likely affects actin-myosin cross-bridge interactions. We compared the Ca2+ sensitivity for force generation and cross-bridge cycling kinetics in neonatal (postnatal days 0-3) and adult (day 84) rats. The force-pCa relationship was determined in Triton-X skinned muscle bundles activated at pCa 9.0 to 4.0. In strips maximally activated at pCa 4.0, the following parameters of cross-bridge cycling were measured: (1) rate of force redevelopment following rapid shortening and restretching (ktr); and (2) isometric stiffness at maximal activation and in rigor. The fraction of attached cross-bridges (alpha fs) and apparent rate constants for cross-bridge attachment (fapp) and detachment (gapp) were derived assuming a two-state model for cross-bridge cycling. Compared to the adult, the force-pCa curve for neonatal cardiac muscle was significantly shifted to the left. Neonatal cardiac muscle also displayed significantly smaller alpha fs, slower ktr and fapp; however, gapp was not significantly different between age groups. These data indicate that weaker force production in neonatal cardiac muscle involves, at least in part, less efficient cross-bridge cycling kinetics.
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Affiliation(s)
- Y S Prakash
- Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
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32
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Kopydlowski KM, Salkowski CA, Cody MJ, van Rooijen N, Major J, Hamilton TA, Vogel SN. Regulation of macrophage chemokine expression by lipopolysaccharide in vitro and in vivo. J Immunol 1999; 163:1537-44. [PMID: 10415057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
The host response to Gram-negative LPS is characterized by an influx of inflammatory cells into host tissues, which is mediated, in part, by localized production of chemokines. The expression and function of chemokines in vivo appears to be highly selective, though the molecular mechanisms responsible are not well understood. All CXC (IFN-gamma-inducible protein (IP-10), macrophage inflammatory protein (MIP)-2, and KC) and CC (JE/monocyte chemoattractant protein (MCP)-1, MCP-5, MIP-1alpha, MIP-1beta, and RANTES) chemokine genes evaluated were sensitive to stimulation by LPS in vitro and in vivo. While IL-10 suppressed the expression of all LPS-induced chemokine genes evaluated in vitro, treatment with IFN-gamma selectively induced IP-10 and MCP-5 mRNAs, but inhibited LPS-induced MIP-2, KC, JE/MCP-1, MIP-1alpha, and MIP-1beta mRNA and/or protein. Like the response to IFN-gamma, LPS-mediated induction of IP-10 and MCP-5 was Stat1 dependent. Interestingly, only the IFN-gamma-mediated suppression of LPS-induced KC gene expression was IFN regulatory factor-2 dependent. Treatment of mice with LPS in vivo also induced high levels of chemokine mRNA in the liver and lung, with a concomitant increase in circulating protein. Hepatic expression of MIP-1alpha, MIP-1beta, RANTES, and MCP-5 mRNAs were dramatically reduced in Kupffer cell-depleted mice, while IP-10, KC, MIP-2, and MCP-1 were unaffected or enhanced. These findings indicate that selective regulation of chemokine expression in vivo may result from differential response of macrophages to pro- and antiinflammatory stimuli and to cell type-specific patterns of stimulus sensitivity. Moreover, the data suggest that individual chemokine genes are differentially regulated in response to LPS, suggesting unique roles during the sepsis cascade.
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MESH Headings
- Animals
- Cells, Cultured
- Chemokines/antagonists & inhibitors
- Chemokines/biosynthesis
- Chemokines/genetics
- Chemokines, CC/antagonists & inhibitors
- Chemokines, CC/biosynthesis
- Chemokines, CC/genetics
- Chemokines, CXC/antagonists & inhibitors
- Chemokines, CXC/biosynthesis
- Chemokines, CXC/genetics
- Down-Regulation/immunology
- Gene Expression Regulation/immunology
- Injections, Intraperitoneal
- Interferon-gamma/pharmacology
- Interleukin-10/physiology
- Kinetics
- Lipopolysaccharides/administration & dosage
- Lipopolysaccharides/antagonists & inhibitors
- Lipopolysaccharides/pharmacology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- Monocyte Chemoattractant Proteins/biosynthesis
- Monocyte Chemoattractant Proteins/genetics
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/biosynthesis
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Affiliation(s)
- K M Kopydlowski
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Salkowski CA, Kopydlowski K, Blanco J, Cody MJ, McNally R, Vogel SN. IL-12 is dysregulated in macrophages from IRF-1 and IRF-2 knockout mice. J Immunol 1999; 163:1529-36. [PMID: 10415056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Macrophages derived from IFN-regulatory factor-1 (IRF-1) and IRF-2 knockout (-/-) and wild-type (+/+) mice were utilized to examine the role of these transcription factors in the regulation of IL-12 mRNA and protein expression. Induction of IL-12 p40 mRNA by LPS was markedly diminished in both IRF-1(-/-) and IRF-2(-/-) macrophages. In contrast, IRF-1(-/-), but not IRF-2(-/-), macrophages exhibited impaired LPS-induced IL-12 p35 mRNA expression. The ability of IFN-gamma to augment LPS-induced IL-12 p40 mRNA further when both stimuli were present simultaneously was significantly diminished in both IRF-1(-/-) and IRF-2(-/-) macrophages, with the most profound impairment observed for IRF-1(-/-) macrophages. Reductions in IL-12 mRNA expression after stimulation with LPS or LPS plus IFN-gamma were accompanied by substantial reductions in IL-12 p40 and IL-12 p70 protein in both IRF-1(-/-) and IRF-2(-/-) macrophages. Priming IRF-1(-/-) and IRF-2(-/-) macrophages with IFN-gamma for 24 h before LPS treatment partially restored impaired IL-12 mRNA and protein production in both IRF-1(-/-) and IRF-2(-/-) macrophages. Depressed IL-12 levels were paralleled by significant reductions in IFN-gamma mRNA expression in IRF-1(-/-) and IRF-2(-/-) macrophages. These results indicate that both IRF-1 and IRF-2 are critical transcription factors in the regulation of macrophage IL-12 and consequently IFN-gamma production.
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Affiliation(s)
- C A Salkowski
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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