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Suárez JAG, Calumby RJN, Silva DP, Barbosa VT, Maranhão FCA, Moreira IF, Melhem MSC, Moreira RTF. Neonatal innate immunity response in invasive candidiasis. BRAZ J BIOL 2024; 84:e275155. [PMID: 38808781 DOI: 10.1590/1519-6984.275155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 03/18/2024] [Indexed: 05/30/2024] Open
Abstract
Infections caused by Candida spp. are frequent in critically hospitalized patients, especially among premature neonates, representing one of the most common healthcare-related infections. Although there is considerable production of current knowledge about the mechanisms of immune response, aspects involved in the newborn's innate defense are not fully understood. The aim of this study was to describe the innate immune mechanisms involved in the defense of neonates against invasive candidiasis. This is an integrative literature review from the Scopus, Scifinder, Medline, Web of Science databases and the electronic libraries ScienceDirect and Scielo, in the period between 2002 and 2020, with rescue based on primary descriptor Immunity Innate plus secondary descriptors Candidiasis Invasive AND Infant Newborn. We have observed the involvement of various mechanisms in the neonatal response against invasive candidiasis, including the recognition, signaling, recruitment, and initiation of an effective immune response. These mechanisms encompass the presence of antimicrobial peptides, phagocytosis, synthesis of reactive oxygen species, inflammatory mediators, and complex cell signaling systems mediated by Pattern Recognition Receptors (PRRs). With this study, it is expected to contribute to the expansion of knowledge about the immunological mechanisms involved in the innate immune response of the newborn against disseminated infections caused by Candida species, and in the same sense, highlight the importance of this knowledge as a reflex in the decrease in mortality in the neonatal period.
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Affiliation(s)
- J A G Suárez
- Universidade Federal de Ouro Preto - UFOP, Ouro Preto, MG, Brasil
| | - R J N Calumby
- Universidade Federal de Alagoas - UFAL, Campus A. C. Simões, Maceió, AL, Brasil
| | - D P Silva
- Universidade Federal de Alagoas - UFAL, Campus A. C. Simões, Maceió, AL, Brasil
| | - V T Barbosa
- Universidade Federal de Alagoas - UFAL, Campus A. C. Simões, Maceió, AL, Brasil
| | - F C A Maranhão
- Universidade Federal de Alagoas - UFAL, Campus A. C. Simões, Maceió, AL, Brasil
| | - I F Moreira
- Universidade Federal de Alagoas - UFAL, Campus A. C. Simões, Maceió, AL, Brasil
| | - M S C Melhem
- Universidade Federal de Mato Grosso do Sul - UFMS, Faculdade de Medicina, Programa de Pós Graduação em Doenças Infecciosas, Campo Grande, MS, Brasil
| | - R T F Moreira
- Universidade Federal de Alagoas - UFAL, Campus A. C. Simões, Maceió, AL, Brasil
- Universidade Federal de Mato Grosso do Sul - UFMS, Faculdade de Medicina, Programa de Pós Graduação em Doenças Infecciosas, Campo Grande, MS, Brasil
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Doğan G, Karagenç N, Esmen K, Kul BÇ, Yeşilkaya H, Akgün Ş, Orman MN, Sandıkçı M, Eren Ü, Ünsal H, Karagenç L. Expression of Toll-Like Receptors in the Lung Tissue of Mouse Fetuses Generated by in vitro Embryo Culture and Embryo Transfer. Cells Tissues Organs 2023; 213:181-202. [PMID: 37105136 DOI: 10.1159/000529974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 02/27/2023] [Indexed: 04/29/2023] Open
Abstract
Mouse fetuses generated by in vitro embryo culture and embryo transfer exhibit impaired lung development, altered composition of pulmonary epithelial cells associated with downregulation of several genes involved in lung development and toll-like receptor (TLR) signaling pathway. The aims of the present study were to determine the expression of all TLRs and to examine if the expression of TLRs, along with genes involved in TLR signaling pathway, is altered in the lung tissue of mouse fetuses generated through embryo culture and embryo transfer. Two experimental (EGs) and one control (CG) group were included in the study. Embryos cultured at 5% CO2-95% air for 95 h or less than 24 h were transferred to pseudo-pregnant females to obtain fetuses comprising EGin vitro (n = 18) and EGin vivo (n = 18), respectively. Fetuses obtained from naturally ovulating females on day 18 of pregnancy served as the CG (n = 18). Western blot and immunohistochemistry were used to determine the expression of TLR proteins. The expression of transcripts encoding TLRs, and the genes involved in TLR signaling pathway (Lbp, Pik3r1, Pik3cb, Nfkbia, and Fos), was determined using qRT-PCR. While all TLRs were expressed by cells lining the bronchial/bronchiolar epithelium of lung tissues in all groups, some of the TLRs were expressed in a specific pattern. When compared to CG, the expression of transcripts encoding TLR-2, -3, -4, -5, -7, -8, -9, -12, -13, Lbp, Pik3r1, Pik3cb, Nfkbia, and Fos was significantly downregulated in both EGs. It appears that stress imposed on embryos at preimplantation stages of development is associated with downregulation of TLRs, along with some of the genes involved in TLR signaling pathway, in the lung tissue during the perinatal period. It remains to be determined if downregulation of TLRs, along with the genes involved in TLR signaling pathway, has any functional consequences in the adult lung tissue.
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Affiliation(s)
- Göksel Doğan
- Department of Histology-Embryology, Faculty of Veterinary Medicine, Adnan Menderes University, Aydın, Turkey
| | - Nedim Karagenç
- Department of Medical Genetics, Faculty of Medicine, Pamukkale University, Denizli, Turkey
| | - Kerem Esmen
- Department of Medical, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Bengi Çınar Kul
- Department of Genetics, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey
| | - Hasan Yeşilkaya
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Şakir Akgün
- Department of Medical Biology, Faculty of Medicine, Kafkas University, Kars, Turkey
| | - Mehmet Nurullah Orman
- Department of Biostatistics and Medical Informatics, Faculty of Medicine, Ege University, İzmir, Turkey
| | - Mustafa Sandıkçı
- Department of Histology-Embryology, Faculty of Veterinary Medicine, Adnan Menderes University, Aydın, Turkey
| | - Ülker Eren
- Department of Histology-Embryology, Faculty of Veterinary Medicine, Adnan Menderes University, Aydın, Turkey
| | - Hümeyra Ünsal
- Department of Physiology, Faculty of Veterinary Medicine, Adnan Menderes University, Aydın, Turkey
| | - Levent Karagenç
- Department of Histology-Embryology, Faculty of Veterinary Medicine, Adnan Menderes University, Aydın, Turkey
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Dias ML, O'Connor KM, Dempsey EM, O'Halloran KD, McDonald FB. Targeting the Toll-like receptor pathway as a therapeutic strategy for neonatal infection. Am J Physiol Regul Integr Comp Physiol 2021; 321:R879-R902. [PMID: 34612068 DOI: 10.1152/ajpregu.00307.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Toll-like receptors (TLRs) are crucial transmembrane receptors that form part of the innate immune response. They play a role in the recognition of various microorganisms and their elimination from the host. TLRs have been proposed as vital immunomodulators in the regulation of multiple neonatal stressors that extend beyond infection such as oxidative stress and pain. The immune system is immature at birth and takes some time to become fully established. As such, babies are especially vulnerable to sepsis at this early stage of life. Findings suggest a gestational age-dependent increase in TLR expression. TLRs engage with accessory and adaptor proteins to facilitate recognition of pathogens and their activation of the receptor. TLRs are generally upregulated during infection and promote the transcription and release of proinflammatory cytokines. Several studies report that TLRs are epigenetically modulated by chromatin changes and promoter methylation upon bacterial infection that have long-term influences on immune responses. TLR activation is reported to modulate cardiorespiratory responses during infection and may play a key role in driving homeostatic instability observed during sepsis. Although complex, TLR signaling and downstream pathways are potential therapeutic targets in the treatment of neonatal diseases. By reviewing the expression and function of key Toll-like receptors, we aim to provide an important framework to understand the functional role of these receptors in response to stress and infection in premature infants.
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Affiliation(s)
- Maria L Dias
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Karen M O'Connor
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Eugene M Dempsey
- Irish Centre for Maternal and Child Health Research, University College Cork, Cork, Ireland.,Department of Pediatrics and Child Health, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland.,Irish Centre for Maternal and Child Health Research, University College Cork, Cork, Ireland
| | - Fiona B McDonald
- Department of Physiology, School of Medicine, College of Medicine and Health, University College Cork, Cork, Ireland.,Irish Centre for Maternal and Child Health Research, University College Cork, Cork, Ireland
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Awasthi S, Rahman N, Rui B, Kumar G, Awasthi V, Breshears M, Kosanke S. Lung and general health effects of Toll-like receptor-4 (TLR4)-interacting SPA4 peptide. BMC Pulm Med 2020; 20:179. [PMID: 32576172 PMCID: PMC7310322 DOI: 10.1186/s12890-020-01187-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 05/13/2020] [Indexed: 11/25/2022] Open
Abstract
Background A surfactant protein-A-derived peptide, which we call SPA4 peptide (amino acids: GDFRYSDGTPVNYTNWYRGE), alleviates lung infection and inflammation. This study investigated the effects of intratracheally administered SPA4 peptide on systemic, lung, and health parameters in an outbred mouse strain, and in an intratracheal lipopolysaccharide (LPS) challenge model. Methods The outbred CD-1 mice were intratracheally administered with incremental doses of SPA4 peptide (0.625–10 μg/g body weight) once every 24 h, for 3 days. Mice left untreated and those treated with vehicle were included as controls. Mice were euthanized after 24 h of last administration of SPA4 peptide. In order to assess the biological activity of SPA4 peptide, C57BL6 mice were intratracheally challenged with 5 μg LPS/g body weight and treated with 50 μg SPA4 peptide via intratracheal route 1 h post LPS-challenge. Mice were euthanized after 4 h of LPS challenge. Signs of sickness and body weights were regularly monitored. At the time of necropsy, blood and major organs were harvested. Blood gas and electrolytes, serum biochemical profiles and SPA4 peptide-specific immunoglobulin G (IgG) antibody levels, and common lung injury markers (levels of total protein, albumin, and lactate, lactate dehydrogenase activity, and lung wet/dry weight ratios) were determined. Lung, liver, spleen, kidney, heart, and intestine were examined histologically. Differences in measured parameters were analyzed among study groups by analysis of variance test. Results The results demonstrated no signs of sickness or changes in body weight over 3 days of treatment with various doses of SPA4 peptide. It did not induce any major toxicity or IgG antibody response to SPA4 peptide. The SPA4 peptide treatment also did not affect blood gas, electrolytes, or serum biochemistry. There was no evidence of injury to the tissues and organs. However, the SPA4 peptide suppressed the LPS-induced lung inflammation. Conclusions These findings provide an initial toxicity profile of SPA4 peptide. Intratracheal administration of escalating doses of SPA4 peptide does not induce any significant toxicity at tissue and organ levels. However, treatment with a dose of 50 μg SPA4 peptide, comparable to 2.5 μg/g body weight, alleviates LPS-induced lung inflammation.
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Affiliation(s)
- Shanjana Awasthi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, 1110 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA.
| | - Negar Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, 1110 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA
| | - Bin Rui
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, 1110 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA
| | - Gaurav Kumar
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, 1110 N. Stonewall Avenue, Oklahoma City, OK, 73117, USA
| | - Vibhudutta Awasthi
- Department of Pharmaceutical Sciences, and Research Imaging Facility, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73117, USA
| | - Melanie Breshears
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Stanley Kosanke
- Division of Comparative Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
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Ma L, Yang J, Yang L, Shi J, Xue J, Li Y, Liu X. Developmental expression of Toll‑like receptors in the guinea pig lung. Mol Med Rep 2017; 15:1243-1251. [PMID: 28098883 PMCID: PMC5367368 DOI: 10.3892/mmr.2017.6129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 11/21/2016] [Indexed: 12/27/2022] Open
Abstract
The guinea pig is a useful model for investigating infectious and non‑infectious lung diseases due to the sensitivity of its respiratory system and susceptibility to infectious agents. Toll‑like receptors (TLRs) are important components of the innate immune response and are critical for lung immune function. In the present study, the differentiation of epithelial cells in the guinea pig lung was examined during gestation by studying anatomic morphology and the major epithelial cell types using cell type‑specific markers. The developmental expression of all 9 TLRs and the TLR signaling adaptors myeloid differentiation factor 88 (MyD88) and tumor necrosis factor receptor associated factor 6 (TRAF‑6) were investigated by reverse transcription‑quantitative polymerase chain reaction and western blotting analysis. The formation of lung lobes in guinea pigs was observed at 45 days of gestation (dGA), along with the expression of the basal cell marker keratin 14 and the alveolar type II cell marker pro‑surfactant protein. However, the cube cell marker secretoglobin family1A member 1 and ciliated cell marker b‑tubulin IV were only detected in the lungs from 52 dGA onward. The expression levels of all TLRs, MyD88 and TRAF‑6 were determined in lung tissues harvested from embryos, newborn, postnatal and adult animals. The expression levels of all TLR signaling components displayed similar dynamic expression patterns with gestation age and postnatal maturation time, except for TLR‑4 and TLR‑7. mRNA expression levels of TLR components were significantly increased in the lungs at 45 and 52 dGA, compared with later developmental stages. These results suggest that TLR expression in the guinea pig lung is developmentally regulated, enhancing the understanding of lung biology in guinea pig models.
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Affiliation(s)
- Lingjie Ma
- Key Laboratory of The Ministry of Education for The Conservation and Utilization of Special Biological Resources of Western China, Ningxia University, Yinchuan, Ningxia 750021, P.R. China
| | - Jiali Yang
- Ningxia Key Laboratory of Clinical and Pathogenic Microbiology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Li Yang
- The Center of Experimental Animals, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Juan Shi
- Ningxia Key Laboratory of Clinical and Pathogenic Microbiology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Jing Xue
- Key Laboratory of The Ministry of Education for The Conservation and Utilization of Special Biological Resources of Western China, Ningxia University, Yinchuan, Ningxia 750021, P.R. China
| | - Yong Li
- Key Laboratory of The Ministry of Education for The Conservation and Utilization of Special Biological Resources of Western China, Ningxia University, Yinchuan, Ningxia 750021, P.R. China
| | - Xiaoming Liu
- Key Laboratory of The Ministry of Education for The Conservation and Utilization of Special Biological Resources of Western China, Ningxia University, Yinchuan, Ningxia 750021, P.R. China
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Yoder BA, Coalson JJ. Animal models of bronchopulmonary dysplasia. The preterm baboon models. Am J Physiol Lung Cell Mol Physiol 2014; 307:L970-7. [PMID: 25281639 DOI: 10.1152/ajplung.00171.2014] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Much of the progress in improved neonatal care, particularly management of underdeveloped preterm lungs, has been aided by investigations of multiple animal models, including the neonatal baboon (Papio species). In this article we highlight how the preterm baboon model at both 140 and 125 days gestation (term equivalent 185 days) has advanced our understanding and management of the immature human infant with neonatal lung disease. Not only is the 125-day baboon model extremely relevant to the condition of bronchopulmonary dysplasia but there are also critical neurodevelopmental and other end-organ pathological features associated with this model not fully discussed in this limited forum. We also describe efforts to incorporate perinatal infection into these preterm models, both fetal and neonatal, and particularly associated with Ureaplasma/Mycoplasma organisms. Efforts to rekindle the preterm primate model for future evaluations of therapies such as stem cell replacement, early lung recruitment interventions coupled with noninvasive surfactant and high-frequency nasal ventilation, and surfactant therapy coupled with antioxidant or anti-inflammatory medications, to name a few, should be undertaken.
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Affiliation(s)
- Bradley A Yoder
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah; and
| | - Jacqueline J Coalson
- Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
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Development of monocyte Toll-like receptor 2 and Toll-like receptor 4 in preterm newborns during the first few months of life. Pediatr Res 2013; 73:685-91. [PMID: 23417037 DOI: 10.1038/pr.2013.36] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Although the immaturity of Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) at birth in preterm newborns is known, their development during the first few months of life remains unclear. METHODS Blood monocytes of preterm newborns (gestational age: 24-36 wk) were obtained every 2 wk when possible in order to perform serial measurements of TLR2 and TLR4 surface expression, as well as lipopolysaccharide (LPS)-induced cytokine production. Measurements using monocytes from term newborns and adults were also performed. RESULTS The monocytes of preterm newborns obtained at birth displayed reduced surface expression of TLR2 and TLR4, and diminished responses of tumor necrosis factor-α (TNF-α) and interleukin (IL)-8 to LPS stimulation. Regardless of gestational age, monocyte expression of TLR2 and TLR4 in preterm newborns increased rapidly within the first 2 wk after birth, quickly reaching those of term newborns. These increases continued for the following 4-6 wk, although the increase began to plateau. By contrast, LPS-induced production of TNF-α and IL-8 did not elevate over this period in preterm newborns. CONCLUSION The blood monocytes of preterm newborns display rapid increase in TLR2 and TLR4 expression during the first few months of life, whereas LPS-induced cytokine production functionality did not improve in parallel.
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Lung dendritic cell developmental programming, environmental stimuli, and asthma in early periods of life. J Allergy (Cairo) 2012; 2012:176468. [PMID: 23209481 PMCID: PMC3503332 DOI: 10.1155/2012/176468] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 09/29/2012] [Accepted: 09/30/2012] [Indexed: 12/22/2022] Open
Abstract
Dendritic cells (DCs) are important cells of our innate immune system. Their role is critical in inducing adaptive immunity, tolerance, or allergic response in peripheral organs—lung and skin. The lung DCs are not developed prenatally before birth. The DCs develop after birth presumably during the first year of life; exposures to any foreign antigen or infectious organisms during this period can significantly affect DC developmental programming and generation of distinct DC phenotypes and functions. These changes can have both short-term and long-term health effects which may be very relevant in childhood asthma and predisposition for a persistent response in adulthood. An understanding of DC development at molecular and cellular levels can help in protecting neonates and infants against problematic environmental exposures and developmental immunotoxicity. This knowledge can eventually help in designing novel pharmacological modulators to skew the DC characteristics and immune responses to benefit the host across a lifetime.
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Awasthi S, Madhusoodhanan R, Wolf R. Surfactant protein-A and toll-like receptor-4 modulate immune functions of preterm baboon lung dendritic cell precursor cells. Cell Immunol 2011; 268:87-96. [PMID: 21439559 PMCID: PMC3104394 DOI: 10.1016/j.cellimm.2011.02.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 02/28/2011] [Indexed: 01/04/2023]
Abstract
Lung infections are important risk factors for an increased morbidity and mortality in prematurely-delivered babies. Immaturity of the innate immune components makes them extremely susceptible to infection. Recently, we isolated lung dendritic cell (DC)-precursor cells from preterm fetal baboons. The isolated cells were found to be defective in phagocytosing Escherichia coli under basal conditions. In this study, we investigated the effects of exogenously-added purified native lung surfactant protein (SP)-A and recombinant toll-like receptor (TLR)-4-MD2 proteins on phagocytic uptake and cytokine secreting ability of fetal baboon lung DC-precursor cells. The cells were pulsed with SP-A and/or TLR4-MD2 proteins and the phagocytic function was investigated by incubating the cells with fluorescent-labeled E. coli bioparticles and analyzed by spectrofluorometry. The amounts of TNF-α secreted in cell-free supernatants were measured by ELISA. Our results demonstrate that SP-A and TLR4-MD2 proteins, whether added alone or together, induce phagocytosis of E. coli (p<0.05). The SP-A does not affect TNF-α secretion, while the TLR4-MD2 protein induces TNF-α. However, simultaneous addition of SP-A with TLR4-MD2 protein reduces the TLR4-MD2-protein induced TNF-α to basal level. In conclusion, our results indicate that an exogenous administration of SP-A can potentially induce phagocytic activity and anti-inflammatory effect in preterm babies, and help control infection and inflammation.
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Affiliation(s)
- Shanjana Awasthi
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK 73117, USA.
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Awasthi S, Brown K, King C, Awasthi V, Bondugula R. A toll-like receptor-4-interacting surfactant protein-A-derived peptide suppresses tumor necrosis factor-α release from mouse JAWS II dendritic cells. J Pharmacol Exp Ther 2010; 336:672-81. [PMID: 21159752 DOI: 10.1124/jpet.110.173765] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Surfactant protein-A (SP-A) and Toll-like receptor-4 (TLR4) proteins are recognized as pathogen-recognition receptors. An exaggerated activation of TLR4 induces inflammatory response, whereas SP-A protein down-regulates inflammation. We hypothesized that SP-A-TLR4 interaction may lead to inhibition of inflammation. In this study, we investigated interaction between native baboon lung SP-A and baboon and human TLR4-MD2 proteins by coimmunoprecipitation/immunoblotting and microwell-based methods. The interaction between SP-A and TLR4-MD2 proteins was then analyzed using a bioinformatics approach. In the in silico model of SP-A-TLR4-MD2 complex, we identified potential binding regions and amino acids at the interface of SP-A-TLR4. Using this information, we synthesized a library of human SP-A-derived peptides that contained interacting amino acids. Next, we tested whether the TLR4-interacting SP-A peptides would suppress inflammatory cytokines. The peptides were screened for any changes in the tumor necrosis factor-α (TNF-α) response against lipopolysaccharide (LPS) stimuli in the mouse JAWS II dendritic cell line. Different approaches used in this study suggested binding between SP-A and TLR4-MD2 proteins. In cells pretreated with peptides, three of seven peptides increased TNF-α production against LPS. However, two of these peptides (SPA4: GDFRYSDGTPVNYTNWYRGE and SPA5: YVGLTEGPSPGDFRYSDFTP) decreased the TNF-α production in LPS-challenged JAWS II dendritic cells; SPA4 peptide showed more pronounced inhibitory effect than SPA5 peptide. In conclusion, we identify a human SP-A-derived peptide (SPA4 peptide) that interacts with TLR4-MD2 protein and inhibits the LPS-stimulated release of TNF-α in JAWS II dendritic cells.
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Affiliation(s)
- Shanjana Awasthi
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK, USA.
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Polglase GR, Dalton RGB, Nitsos I, Knox CL, Pillow JJ, Jobe AH, Moss TJM, Newnham JP, Kallapur SG. Pulmonary vascular and alveolar development in preterm lambs chronically colonized with Ureaplasma parvum. Am J Physiol Lung Cell Mol Physiol 2010; 299:L232-41. [PMID: 20495079 DOI: 10.1152/ajplung.00369.2009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Ureaplasma species, the most commonly isolated microorganisms in women with chorioamnionitis, are associated with preterm delivery. Chorioamnionitis increases the risk and severity of bronchopulmonary dysplasia and persistent pulmonary hypertension in newborns. It is not known whether the timing of exposure to inflammation in utero is an important contributor to the pathogenesis of bronchopulmonary dysplasia. We hypothesized that chronic inflammation would alter the pulmonary air space and vascular development after 70 days of exposure to infection. Pregnant ewes were given intra-amniotic injection of Ureaplasma parvum serovars 3 or 6 at low (2 x 10(4) cfu) or high doses (2 x 10(7) cfu) or media (controls) at 55 days gestational age. Fetuses were delivered at 125 days (term = 150 days). U. parvum was grown from the lungs of all exposed fetuses, and neutrophils and monocytes were increased in the air spaces. Lung mRNA expression of IL-1beta and IL-8, but not IL-6, was modestly increased in U. parvum-exposed fetuses. U. parvum exposure increased surfactant and improved lung gas volumes. The changes in lung inflammation and maturation were independent of serovar or dose. Exposure to U. parvum did not change multiple indices of air space or vascular development. Parenchymal elastin and collagen content were similar between groups. Expression of several endothelial proteins and pulmonary resistance arteriolar media thickness were also not different between groups. We conclude that chronic exposure to U. parvum does not cause sustained effects on air space or vascular development in premature lambs.
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Wolfs TGAM, Derikx JPM, Hodin CMIM, Vanderlocht J, Driessen A, de Bruïne AP, Bevins CL, Lasitschka F, Gassler N, van Gemert WG, Buurman WA. Localization of the lipopolysaccharide recognition complex in the human healthy and inflamed premature and adult gut. Inflamm Bowel Dis 2010; 16:68-75. [PMID: 20014022 DOI: 10.1002/ibd.20995] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Microbiota in the intestinal lumen provide an abundant source of potentially detrimental antigens, including lipopolysaccharide (LPS), a potent immunostimulatory product of Gram-negative bacteria recognized by the host via TLR-4 and MD-2. An aberrant immune response to LPS or other bacterial antigens has been linked to inflammatory bowel disease (IBD) and necrotizing enterocolitis (NEC). METHODS We investigated which cells express MD-2 in the normal and inflamed ileum from neonates and adults by immunohistochemistry. Moreover, MD-2 and TLR4 mRNA expression in normal adult ileum was studied by reverse-transcription polymerase chain reaction (RT-PCR) on cells isolated by laser capture microdissection. RESULTS Premature infants did not show MD-2 expression either in epithelial cells or in the lamina propria. Similarly, MD-2 was absent in epithelial cells and lamina propria inflammatory cells in preterm infants with NEC. MD-2 protein in the healthy term neonatal and adult ileum was predominantly expressed by Paneth cells and some resident inflammatory cells in the lamina propria. MD-2 and TLR-4 mRNA expression was restricted to crypt cells. Also in IBD, Paneth cells were still the sole MD-2-expressing epithelial cells, whereas inflammatory cells (mainly plasma cells) were responsible for the vast majority of the MD-2 expression. CONCLUSIONS The absence of MD-2 in the immature neonatal gut suggests impaired LPS sensing, which could predispose neonates to NEC upon microbial colonization of the immature intestine. The apparent expression of MD-2 by Paneth cells supports the critical concept that these cells respond to luminal bacterial products in order to maintain homeostasis with the intestinal microbiota in vivo.
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Affiliation(s)
- Tim G A M Wolfs
- Department of Surgery, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University Medical Centre, Maastricht, the Netherlands
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Viscardi RM, Hasday JD. Role of Ureaplasma species in neonatal chronic lung disease: epidemiologic and experimental evidence. Pediatr Res 2009; 65:84R-90R. [PMID: 19190528 PMCID: PMC2920621 DOI: 10.1203/pdr.0b013e31819dc2f9] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The contribution of Ureaplasma respiratory tract colonization to the pathogenesis of bronchopulmonary dysplasia in preterm infants has been debated for over 20 y. We review the current understanding of the role of inflammation in altered developmental signaling in the preterm lung and the evidence from human studies and experimental models that Ureaplasma-mediated inflammation produces the BPD phenotype. We propose that Ureaplasma infection initiated in utero and augmented postnatally by exposure to volutrauma and oxygen elicits a sustained, dysregulated inflammatory response in the immature lung that impairs alveolarization, and stimulates myofibroblast proliferation and excessive collagen and elastin deposition. Potential strategies to prevent or ameliorate the effects of Ureaplasma infection in utero and in the preterm lung are discussed.
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Affiliation(s)
- Rose Marie Viscardi
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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Hall C, Flores MV, Chien A, Davidson A, Crosier K, Crosier P. Transgenic zebrafish reporter lines reveal conserved Toll-like receptor signaling potential in embryonic myeloid leukocytes and adult immune cell lineages. J Leukoc Biol 2009; 85:751-65. [PMID: 19218482 DOI: 10.1189/jlb.0708405] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The immune response of a host to an invading pathogen is dependent on the capacity of its immune cell compartment to recognize highly conserved pathogen components using an ancient class of pattern recognition receptors known as Toll-like receptors (TLRs). Initiation of TLR-mediated signaling results in the induction of proinflammatory cytokines that help govern the scale and duration of any ensuing response. Specificity for TLR signaling is, in part, a result of the differential recruitment of intracellular adaptor molecules. Of these, MyD88 is required for the majority of TLR signaling. Zebrafish have been shown to possess TLRs and adaptor molecules throughout early development, including MyD88, strongly suggesting conservation of this ancient defense mechanism. However, information about which embryonic cells/tissues possess this conserved signaling potential is lacking. To help define which embryonic cells, in particular, those of the innate immune system, have the potential for MyD88-dependent, TLR-mediated signaling, we generated transgenic reporter lines using regulatory elements of the myd88 gene to drive the fluorescent reporters enhanced GFP and Discosoma red fluorescent protein 2 within live zebrafish. These lines possess fluorescently marked cells/tissues consistent with endogenous myd88 expression, including a subset of myeloid leukocytes. These innate immune cells were confirmed to express other TLR adaptors including Mal, trif, and Sarm. Live wound-healing and infection assays validated the potential of these myd88-expressing leukocytes to participate in immune responses. These lines will provide a valuable resource for further resolving the contribution of MyD88 to early vertebrate immunity.
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Affiliation(s)
- Chris Hall
- Department of Molecular Medicine and Pathology, School of Medical Sciences, The University of Auckland, Auckland, New Zealand
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