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1.
Artigo em Inglês | MEDLINE | ID: mdl-38657143

RESUMO

Idiopathic pulmonary fibrosis (IPF) is an aging-associated interstitial lung disease resulting from repeated epithelial injury and inadequate epithelial repair. Alveolar type II cells (AEC2) are progenitor cells that maintain epithelial homeostasis and repair the lung after injury. In the current study, we assessed lipid metabolism in AEC2s from human lungs of IPF patients and healthy donors, as well as AEC2s from bleomycin-injured young and old mice. Through single cell RNA sequencing (scRNA-seq), we observed that lipid metabolism-related genes were downregulated in IPF AEC2s and bleomycin-injured mouse AEC2s. Aging aggravated this decrease and hindered recovery of lipid metabolism gene expression in AEC2s after bleomycin injury. Pathway analyses revealed down-regulation of genes related to lipid biosynthesis and fatty acid -oxidation in AEC2s from IPF lungs and bleomycin-injured, aged mouse lungs compared to the respective controls. We confirmed decreased cellular lipid content in AEC2s from IPF lungs and bleomycin-injured, aged mouse lungs using immunofluorescence staining and flow cytometry. We further show that lipid metabolism was associated with AEC2 progenitor function. Lipid supplementation and peroxisome proliferator activated receptor gamma (PPARγ) activation promoted progenitor renewal capacity of both human and mouse AEC2s in 3D organoid cultures. Lipid supplementation also increased AEC2 proliferation and expression of SFTPC in AEC2s. In summary, we identified a lipid metabolism deficiency in AEC2s from lungs of patients with IPF and bleomycin-injured aged mice. Restoration of lipid metabolism homeostasis in AEC2s might promote AEC2 progenitor function and offer new opportunities for therapeutic approaches to IPF. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

2.
Artigo em Inglês | MEDLINE | ID: mdl-38771132

RESUMO

The alveolar Type II epithelial (AEC2) cells act as stem cells in the lung for alveolar epithelial maintenance and repair. Chemokine CXCL10 is expressed in injured tissues, modulating multiple cellular functions. AEC2s, previously reported to release chemokines to recruit leukocytes, were found in our study to secrete CXCL10 after bleomycin injury. We found that Sftpc-Cxcl10 transgenic mice were protected from bleomycin injury. The transgenic mice showed an increase in the AEC2 population in the lung by flow cytometry analysis. Both endogenous and exogenous CXCL10 promoted the colony formation efficiency of AEC2s in a 3D organoid growth assay. We identified that the regenerative effect of CXCL10 was CXCR3 independent using Cxcr3-deficient mice, but it was related to the TrkA pathway. Binding experiments showed that CXCL10 interacted with TrkA directly and reversibly. This study demonstrates a previously unidentified AEC2 autocrine signaling of CXCL10 to promote their regeneration and proliferation, probably involving a CXCR3-independent TrkA pathway.

3.
Am J Respir Cell Mol Biol ; 68(3): 302-313, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36318668

RESUMO

Loss of epithelial integrity, bronchiolarization, and fibroblast activation are key characteristics of idiopathic pulmonary fibrosis (IPF). Prolonged accumulation of basal-like cells in IPF may impact the fibrotic niche to promote fibrogenesis. To investigate their role in IPF, basal cells were isolated from IPF explant and healthy donor lung tissues. Single-cell RNA sequencing was used to assess differentially expressed genes in basal cells. Basal cell and niche interaction was demonstrated with the sLP-mCherry niche labeling system. Luminex assays were used to assess cytokines secreted by basal cells. The role of basal cells in fibroblast activation was studied. Three-dimensional organoid culture assays were used to interrogate basal cell effects on AEC2 (type 2 alveolar epithelial cell) renewal capacity. Perturbation was used to investigate WNT7A function in vitro and in a repetitive bleomycin model in vivo. We found that WNT7A is highly and specifically expressed in basal-like cells. Proteins secreted by basal cells can be captured by neighboring fibroblasts and AEC2s. Basal cells or basal cell-conditioned media activate fibroblasts through WNT7A. Basal cell-derived WNT7A inhibits AEC2 progenitor cell renewal in three-dimensional organoid cultures. Neutralizing antibodies against WNT7A or a small molecule inhibitor of Frizzled signaling abolished basal cell-induced fibroblast activation and attenuated lung fibrosis in mice. In summary, basal cells and basal cell-derived WNT7A are key components of the fibrotic niche, providing a unique non-stem cell function of basal cells in IPF progression and a novel targeting strategy for IPF.


Assuntos
Fibrose Pulmonar Idiopática , Animais , Camundongos , Bleomicina/farmacologia , Fibroblastos/metabolismo , Fibrose , Fibrose Pulmonar Idiopática/metabolismo , Pulmão/patologia , Transdução de Sinais
4.
Am J Respir Cell Mol Biol ; 60(1): 41-48, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30130411

RESUMO

Severe pulmonary fibrosis such as idiopathic pulmonary fibrosis (IPF) is characterized by the accumulation of extracellular matrix and fibroblast activation. Targeting fibroblast activation has contributed to the development of antifibrotic therapeutics for patients with IPF. Mitogen-activated protein kinase-activated protein kinase 2 (MK2), downstream in the transforming growth factor-ß/p38 mitogen-activated protein kinase pathway, has been implicated in inflammatory and fibrosing diseases. Increased concentrations of activated MK2 were expressed in IPF lung and in the mouse bleomycin model of lung fibrosis. The aim of the present study was to determine the role and the mechanisms of MK2 in fibroblast invasion and lung fibrosis. Our results showed that an MK2 inhibitor (MMI-0100) was able to inhibit the invasive capacity of lung fibroblasts isolated from patients with IPF, as well as fibroblasts isolated from both wild-type mice and mice with overexpressing hyaluronan synthase 2 (HAS2) in the myofibroblast compartment. We previously showed that hyaluronan and HAS2 regulate fibroblast invasion and lung fibrosis in vivo. The results of the present study showed that MMI-0100 reduced transforming growth factor-ß-induced hyaluronan production in human and mouse fibroblasts in vitro and that HAS2 mediated MK2 activation, suggesting a feed-forward loop in fibroblast activation. More importantly, MK2 inhibition attenuated hyaluronan accumulation and reduced collagen content in bleomycin-injured mouse lungs in vivo. Conditional deletion of MK2 in fibroblasts attenuated bleomycin-induced lung fibrosis. These data provide evidence that MK2 has a role in fibroblast invasion and fibrosis and may be a novel therapeutic target in pulmonary fibrosis.


Assuntos
Fibroblastos/patologia , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Peptídeos/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Fibrose Pulmonar/prevenção & controle , Índice de Gravidade de Doença , Animais , Antibióticos Antineoplásicos/toxicidade , Apoptose/efeitos dos fármacos , Bleomicina/toxicidade , Células Cultivadas , Fibroblastos/efeitos dos fármacos , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/patologia
5.
Am J Respir Cell Mol Biol ; 57(6): 721-732, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28799781

RESUMO

Successful repair and renewal of alveolar epithelial cells (AECs) are critical in prohibiting the accumulation of myofibroblasts in pulmonary fibrogenesis. MicroRNAs (miRNAs) are multifocal regulators involved in lung injury and repair. However, the contribution of miRNAs to AEC2 renewal and apoptosis is incompletely understood. We report that miRNA-29c (miR-29c) expression is lower in AEC2s of individuals with idiopathic pulmonary fibrosis than in healthy lungs. Epithelial cells overexpressing miR-29c show higher proliferative rates and viability. miR-29c protects epithelial cells from apoptosis by targeting forkhead box O3a (Foxo3a). Both overexpression of miR-29c conventionally and AEC2s specifically lead to less fibrosis and better recovery in vivo. Furthermore, deficiency of miR-29c in AEC2s results in higher apoptosis and reduced epithelial renewal. Interestingly, a gene network including a subset of apoptotic genes was coregulated by both Toll-like receptor 4 and miR-29c. Taken together, miR-29c maintains epithelial integrity and promotes recovery from lung injury, thereby attenuating lung fibrosis in mice.


Assuntos
Apoptose , Células Epiteliais/metabolismo , Fibrose Pulmonar Idiopática/metabolismo , MicroRNAs/metabolismo , Mucosa Respiratória/metabolismo , Animais , Células Epiteliais/patologia , Feminino , Humanos , Fibrose Pulmonar Idiopática/induzido quimicamente , Fibrose Pulmonar Idiopática/genética , Fibrose Pulmonar Idiopática/patologia , Masculino , Camundongos , MicroRNAs/genética , Mucosa Respiratória/patologia , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo
6.
J Immunol ; 188(5): 2437-44, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22287715

RESUMO

The molecular mechanisms of acute lung injury are incompletely understood. MicroRNAs (miRNAs) are crucial biological regulators that act by suppressing their target genes and are involved in a variety of pathophysiologic processes. miR-127 appears to be downregulated during lung injury. We set out to investigate the role of miR-127 in lung injury and inflammation. Expression of miR-127 significantly reduced cytokine release by macrophages. Looking into the mechanisms of regulation of inflammation by miR-127, we found that IgG FcγRI (CD64) was a target of miR-127, as evidenced by reduced CD64 protein expression in macrophages overexpressing miR-127. Furthermore, miR-127 significantly reduced the luciferase activity with a reporter construct containing the native 3' untranslated region of CD64. Importantly, we demonstrated that miR-127 attenuated lung inflammation in an IgG immune complex model in vivo. Collectively, these data show that miR-127 targets macrophage CD64 expression and promotes the reduction of lung inflammation. Understanding how miRNAs regulate lung inflammation may represent an attractive way to control inflammation induced by infectious or noninfectious lung injury.


Assuntos
Lesão Pulmonar Aguda/imunologia , Lesão Pulmonar Aguda/prevenção & controle , Marcação de Genes/métodos , Mediadores da Inflamação/fisiologia , MicroRNAs/fisiologia , Receptores de IgG/metabolismo , Lesão Pulmonar Aguda/patologia , Animais , Complexo Antígeno-Anticorpo/toxicidade , Linhagem Celular , Citocinas/antagonistas & inibidores , Citocinas/metabolismo , Feminino , Células HEK293 , Humanos , Mediadores da Inflamação/metabolismo , Infecções por Lentivirus/imunologia , Infecções por Lentivirus/patologia , Infecções por Lentivirus/prevenção & controle , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/biossíntese , MicroRNAs/genética , Dados de Sequência Molecular , Pneumonia Viral/imunologia , Pneumonia Viral/patologia , Pneumonia Viral/prevenção & controle , Receptores de IgG/antagonistas & inibidores , Receptores de IgG/biossíntese , Receptores de IgG/genética , Células U937
7.
Artigo em Inglês | MEDLINE | ID: mdl-38736470

RESUMO

The molecular mechanisms that regulate progressive pulmonary fibrosis remain poorly understood. Type 2 alveolar epithelial cells (AEC2s) function as adult stem cells in the lung. We previously showed that there is a loss of AEC2s and a failure of AEC2 renewal in the lungs of idiopathic pulmonary fibrosis (IPF) patients. We also reported that beta-arrestins are the key regulators of fibroblast invasion, and beta-arrestin 1 and 2 deficient mice exhibit decreased mortality, decreased matrix deposition, and increased lung function in bleomycin-induced lung fibrosis. However, the role of beta-arrestins in AEC2 regeneration is unclear. In this study, we investigated the role and mechanism of Arrestin beta 1 (ARRB1) in AEC2 renewal and in lung fibrosis. We used conventional deletion as well as cell type-specific deletion of ARRB1 in mice and found that Arrb1 deficiency in fibroblasts protects mice from lung fibrosis, and the knockout mice exhibit enhanced AEC2 regeneration in vivo, suggesting a role of fibroblast-derived ARRB1 in AEC2 renewal. We further found that Arrb1-deficient fibroblasts promotes AEC2 renewal in 3D organoid assays. Mechanistically, we found that CCL7 is among the top downregulated cytokines in Arrb1 deficient fibroblasts and CCL7 inhibits AEC2 regeneration in 3D organoid experiments. Therefore, fibroblast ARRB1 mediates AEC2 renewal, possibly by releasing chemokine CCL7, leading to fibrosis in the lung.

9.
J Immunol ; 187(9): 4800-8, 2011 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-21930959

RESUMO

Inhalation of ambient ozone alters populations of lung macrophages. However, the impact of altered lung macrophage populations on the pathobiology of ozone is poorly understood. We hypothesized that subpopulations of macrophages modulate the response to ozone. We exposed C57BL/6 mice to ozone (2 ppm × 3 h) or filtered air. At 24 h after exposure, the lungs were harvested and digested and the cells underwent flow cytometry. Analysis revealed a novel macrophage subset present in ozone-exposed mice, which were distinct from resident alveolar macrophages and identified by enhanced Gr-1(+) expression [Gr-1 macrophages (Gr-1 Macs)]. Further analysis showed that Gr-1(+) Macs exhibited high expression of MARCO, CX3CR1, and NAD(P)H:quinone oxioreductase 1. Gr-1(+) Macs were present in the absence of CCR2, suggesting that they were not derived from a CCR2-dependent circulating intermediate. Using PKH26-PCL to label resident phagocytic cells, we demonstrated that Gr-1 Macs were derived from resident lung cells. This new subset was diminished in the absence of CX3CR1. Interestingly, CX3CR1-null mice exhibited enhanced responses to ozone, including increased airway hyperresponsiveness, exacerbated neutrophil influx, accumulation of 8-isoprostanes and protein carbonyls, and increased expression of cytokines (CXCL2, IL-1ß, IL-6, CCL2, and TNF-α). Our results identify a novel subset of lung macrophages, which are derived from a resident intermediate, are dependent upon CX3CR1, and appear to protect the host from the biological response to ozone.


Assuntos
Diferenciação Celular/imunologia , Mediadores da Inflamação/fisiologia , Macrófagos Alveolares/imunologia , Estresse Oxidativo/imunologia , Ozônio/administração & dosagem , Receptores de Quimiocinas/fisiologia , Administração Intranasal , Animais , Receptor 1 de Quimiocina CX3C , Diferenciação Celular/genética , Feminino , Inflamação/genética , Inflamação/imunologia , Inflamação/prevenção & controle , Mediadores da Inflamação/administração & dosagem , Mediadores da Inflamação/uso terapêutico , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/patologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Estresse Oxidativo/genética , Ozônio/efeitos adversos , Receptores de Quimiocinas/biossíntese , Receptores de Quimiocinas/deficiência , Receptores de Quimiocinas/genética , Receptores Imunológicos/biossíntese , Receptores Imunológicos/genética
10.
Elife ; 122023 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-37314162

RESUMO

Aging is a critical risk factor in idiopathic pulmonary fibrosis (IPF). Dysfunction and loss of type 2 alveolar epithelial cells (AEC2s) with failed regeneration is a seminal causal event in the pathogenesis of IPF, although the precise mechanisms for their regenerative failure and demise remain unclear. To systematically examine the genomic program changes of AEC2s in aging and after lung injury, we performed unbiased single-cell RNA-seq analyses of lung epithelial cells from uninjured or bleomycin-injured young and old mice, as well as from lungs of IPF patients and healthy donors. We identified three AEC2 subsets based on their gene signatures. Subset AEC2-1 mainly exist in uninjured lungs, while subsets AEC2-2 and AEC2-3 emerged in injured lungs and increased with aging. Functionally, AEC2 subsets are correlated with progenitor cell renewal. Aging enhanced the expression of the genes related to inflammation, stress responses, senescence, and apoptosis. Interestingly, lung injury increased aging-related gene expression in AEC2s even in young mice. The synergistic effects of aging and injury contributed to impaired AEC2 recovery in aged mouse lungs after injury. In addition, we also identified three subsets of AEC2s from human lungs that formed three similar subsets to mouse AEC2s. IPF AEC2s showed a similar genomic signature to AEC2 subsets from bleomycin-injured old mouse lungs. Taken together, we identified synergistic effects of aging and AEC2 injury in transcriptomic and functional analyses that promoted fibrosis. This study provides new insights into the interactions between aging and lung injury with interesting overlap with diseased IPF AEC2 cells.


Assuntos
Lesão Pulmonar , Fibrose Pulmonar , Humanos , Camundongos , Animais , Fibrose Pulmonar/patologia , Lesão Pulmonar/induzido quimicamente , Lesão Pulmonar/metabolismo , Pulmão/patologia , Envelhecimento , Bleomicina/toxicidade
11.
Am J Respir Cell Mol Biol ; 46(5): 592-8, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22162905

RESUMO

Chemokines and chemokine receptors have been implicated in the pathogenesis of bronchiolitis. CXCR3 ligands (CXCL10, CXCL9, and CXCL11) were elevated in patients with bronchiolitis obliterans syndrome (BOS) and chronic allorejection. Studies also suggested that blockage of CXCR3 or its ligands changed the outcome of T-cell recruitment and airway obliteration. We wanted to determine the role of the chemokine CXCL10 in the pathogenesis of bronchiolitis and BOS. In this study, we found that CXCL10 mRNA levels were significantly increased in patients with BOS. We generated transgenic mice expressing a mouse CXCL10 cDNA under control of the rat CC10 promoter. Six-month-old CC10-CXCL10 transgenic mice developed bronchiolitis characterized by airway epithelial hyperplasia and developed peribronchiolar and perivascular lymphocyte infiltration. The airway hyperplasia and T-cell inflammation were dependent on the presence of CXCR3. Therefore, long-term exposure of the chemokine CXCL10 in the lung causes bronchiolitis-like inflammation in mice.


Assuntos
Bronquiolite/fisiopatologia , Quimiocina CXCL10/fisiologia , Animais , Sequência de Bases , Líquido da Lavagem Broncoalveolar , Quimiocina CXCL10/genética , Primers do DNA , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Imuno-Histoquímica , Camundongos , Camundongos Transgênicos , Reação em Cadeia da Polimerase , RNA Mensageiro/genética
12.
Am J Physiol Lung Cell Mol Physiol ; 302(9): L933-40, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22287613

RESUMO

CC chemokine ligand-2 (CCL2)/monocyte chemoattractant protein (MCP)-1 expression is upregulated during pulmonary inflammation, and the CCL2-CCR2 axis plays a critical role in leukocyte recruitment and promotion of host defense against infection. The role of CCL2 in mediating macrophage subpopulations in the pathobiology of noninfectious lung injury is unknown. The goal of this study was to examine the role of CCL2 in noninfectious acute lung injury. Our results show that lung-specific overexpression of CCL2 protected mice from bleomycin-induced lung injury, characterized by significantly reduced mortality, reduced neutrophil accumulation, and decreased accumulation of the inflammatory mediators IL-6, CXCL2 (macrophage inflammatory protein-2), and CXCL1 (keratinocyte-derived chemokine). There were dramatic increases in the recruitment of myosin heavy chain (MHC) II IA/IE(int)CD11c(int) cells, exudative macrophages, and dendritic cells in Ccl2 transgenic mouse lungs both at baseline and after bleomycin treatment compared with levels in wild-type mice. We further demonstrated that MHCII IA/IE(int)CD11c(int) cells engulfed apoptotic cells during acute lung injury. Our data suggested a previously undiscovered role for MHCII IA/IE(int)CD11c(int) cells in apoptotic cell clearance and inflammation resolution.


Assuntos
Lesão Pulmonar Aguda/patologia , Apoptose , Quimiocina CCL2/fisiologia , Pulmão/patologia , Macrófagos/fisiologia , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/metabolismo , Animais , Bleomicina , Antígeno CD11c/metabolismo , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Feminino , Humanos , Inflamação/metabolismo , Mediadores da Inflamação/metabolismo , Células Jurkat , Pulmão/metabolismo , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Cadeias Pesadas de Miosina/metabolismo , Neutrófilos/metabolismo , Neutrófilos/fisiologia , Fagocitose , Receptores CCR2/deficiência , Receptores CCR2/genética , Regulação para Cima
13.
J Clin Invest ; 132(11)2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35389887

RESUMO

Type 2 alveolar epithelial cells (AEC2s) function as progenitor cells in the lung. We have shown previously that failure of AEC2 regeneration results in progressive lung fibrosis in mice and is a cardinal feature of idiopathic pulmonary fibrosis (IPF). In this study, we identified deficiency of a specific zinc transporter, SLC39A8 (ZIP8), in AEC2s from both IPF lungs and lungs of old mice. Loss of ZIP8 expression was associated with impaired renewal capacity of AEC2s and enhanced lung fibrosis. ZIP8 regulation of AEC2 progenitor function was dependent on SIRT1. Replenishment with exogenous zinc and SIRT1 activation promoted self-renewal and differentiation of AEC2s from lung tissues of IPF patients and old mice. Deletion of Zip8 in AEC2s in mice resulted in impaired AEC2 renewal, increased susceptibility to bleomycin injury, and development of spontaneous lung fibrosis. Therapeutic strategies to restore zinc metabolism and appropriate SIRT1 signaling could improve AEC2 progenitor function and mitigate ongoing fibrogenesis.


Assuntos
Proteínas de Transporte de Cátions , Fibrose Pulmonar Idiopática , Envelhecimento , Células Epiteliais Alveolares , Animais , Bleomicina , Proteínas de Transporte de Cátions/metabolismo , Humanos , Fibrose Pulmonar Idiopática/genética , Fibrose Pulmonar Idiopática/metabolismo , Pulmão/metabolismo , Camundongos , Sirtuína 1/genética , Sirtuína 1/metabolismo , Células-Tronco/metabolismo , Zinco/metabolismo
14.
J Exp Med ; 219(10)2022 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-35980387

RESUMO

Progressive tissue fibrosis, including idiopathic pulmonary fibrosis (IPF), is characterized by excessive recruitment of fibroblasts to sites of tissue injury and unremitting extracellular matrix deposition associated with severe morbidity and mortality. However, the molecular mechanisms that control progressive IPF have yet to be fully determined. Previous studies suggested that invasive fibroblasts drive disease progression in IPF. Here, we report profiling of invasive and noninvasive fibroblasts from IPF patients and healthy donors. Pathway analysis revealed that the activated signatures of the invasive fibroblasts, the top of which was ERBB2 (HER2), showed great similarities to those of metastatic lung adenocarcinoma cancer cells. Activation of HER2 in normal lung fibroblasts led to a more invasive genetic program and worsened fibroblast invasion and lung fibrosis, while antagonizing HER2 signaling blunted fibroblast invasion and ameliorated lung fibrosis. These findings suggest that HER2 signaling may be a key driver of fibroblast invasion and serve as an attractive target for therapeutic intervention in IPF.


Assuntos
Fibrose Pulmonar Idiopática , Neoplasias , Matriz Extracelular/metabolismo , Fibroblastos/metabolismo , Fibrose , Humanos , Fibrose Pulmonar Idiopática/metabolismo , Pulmão/patologia , Neoplasias/patologia
15.
Am J Respir Cell Mol Biol ; 45(4): 781-8, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21330464

RESUMO

The chemokine, CXCL10, and its cognate receptor, CXCR3, are important mediators of the pathobiology of lung fibrosis. Macrophages are a known source of CXCL10, but their specific source in the lung is poorly defined due to incomplete characterization of macrophage subpopulations. We recently developed a novel flow cytometric approach that discriminates resident alveolar macrophages from recruited exudative macrophages (ExMacs) after infectious lung injury. We hypothesized that ExMacs are present after noninfectious lung injury with bleomycin, and are a source of CXCL10. We found that ExMacs are recruited to the lung after injury, peaking at Day 7, then maintained through Day 28. ExMac recruitment was significantly reduced, but not abolished, in CCR2 null mice. ExMacs, but not alveolar macrophages, produce CXCL10, both constitutively and after stimulation with hyaluronan (HA) fragments. Interestingly, ExMac stimulation with LPS resulted in complete suppression of CXCL10. In contrast, ExMacs produced TNF-α and CXCL2/MIP-2 (Macrophage Inflammatory Protein-2) after stimulation with both HA and LPS. ExMacs were present in CXCR3 null mice after bleomycin, but produced minimal CXCL10. This impairment was overcome by administration of exogenous IFN-γ or IFN-γ with HA. Collectively, these data suggest that ExMacs are recruited and maintained in the lung after noninfectious lung injury, are a source of a variety of cytokines, but importantly, are essential for the production of antifibrotic CXCL10. Understanding the contribution of ExMacs to the pathobiology of lung injury and repair could lead to new treatment options for fibrosing lung diseases.


Assuntos
Quimiocina CXCL10/metabolismo , Quimiotaxia , Pulmão/imunologia , Macrófagos/imunologia , Fibrose Pulmonar/imunologia , Animais , Bleomicina , Receptor 1 de Quimiocina CX3C , Quimiocina CXCL2/metabolismo , Células Dendríticas/imunologia , Modelos Animais de Doenças , Exsudatos e Transudatos/imunologia , Feminino , Citometria de Fluxo , Ácido Hialurônico/metabolismo , Interferon gama/metabolismo , Lipopolissacarídeos/farmacologia , Pulmão/efeitos dos fármacos , Pulmão/patologia , Macrófagos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fragmentos de Peptídeos/metabolismo , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/genética , Fibrose Pulmonar/patologia , Receptores CCR2/genética , Receptores CCR2/metabolismo , Receptores CXCR3/genética , Receptores CXCR3/metabolismo , Receptores de Quimiocinas/genética , Receptores de Quimiocinas/metabolismo , Fatores de Tempo , Fator de Necrose Tumoral alfa/metabolismo
16.
Physiol Genomics ; 43(9): 479-87, 2011 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-21266501

RESUMO

The molecular mechanisms of lung injury and fibrosis are incompletely understood. MicroRNAs (miRNAs) are crucial biological regulators that act by suppressing their target genes and are involved in a variety of pathophysiological processes. To gain insight into miRNAs in the regulation of lung fibrosis, total RNA was isolated from mouse lungs harvested at different days after bleomycin treatment, and miRNA array with 1,810 miRNA probes was performed thereafter. MiRNAs expressed in lungs with bleomycin treatment at different time points were compared with miRNAs expressed in lungs without bleomycin treatment, resulting in 161 miRNAs differentially expressed. Furthermore, miRNA expression patterns regulated in initial and late periods after bleomycin were identified. Target genes were predicted in silico for differentially expressed miRNAs, including let-7f, let-7g, miR-196b, miR-16, miR-195, miR-25, miR-144, miR-351, miR-153, miR-468, miR-449b, miR-361, miR-700, miR-704, miR-717, miR-10a, miR-211, miR-34a, miR-367, and miR-21. Target genes were then cross-referenced to the molecular pathways, suggesting that the differentially expressed miRNAs regulate apoptosis, Wnt, Toll-like receptor, and TGF-ß signaling. Our study demonstrated a relative abundance of miRNA levels in bleomycin-induced lung fibrosis. The miRNAs and their potential target genes identified may contribute to the understanding of the complex transcriptional program of lung fibrosis.


Assuntos
Regulação da Expressão Gênica , MicroRNAs/metabolismo , Fibrose Pulmonar/genética , Animais , Bleomicina , Perfilação da Expressão Gênica , Camundongos , Camundongos Endogâmicos C57BL , Análise de Sequência com Séries de Oligonucleotídeos , Fibrose Pulmonar/induzido quimicamente , Transdução de Sinais , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo
17.
Sci Adv ; 7(24)2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34108218

RESUMO

Recent studies have identified impaired type 2 alveolar epithelial cell (ATII) renewal in idiopathic pulmonary fibrosis (IPF) human organoids and severe fibrosis when ATII is defective in mice. ATIIs function as progenitor cells and require supportive signals from the surrounding mesenchymal cells. The mechanisms by which mesenchymal cells promote ATII progenitor functions in lung fibrosis are incompletely understood. We identified growth hormone receptor (GHR) is mainly expressed in mesenchymal cells, and its expression is substantially decreased in IPF lungs. Higher levels of GHR expression correlated with better lung function in patients with IPF. Profibrotic mesenchymal cells retarded ATII growth and were associated with suppressed vesicular GHR expression. Vesicles enriched with Ghr promote ATII proliferation and diminished pulmonary fibrosis in mesenchymal Ghr-deficient mice. Our findings demonstrate a previously unidentified mesenchymal paracrine signaling coordinated by GHR that is capable of supporting ATII progenitor cell renewal and limiting the severity of lung fibrosis.


Assuntos
Células Epiteliais Alveolares/fisiologia , Fibrose Pulmonar Idiopática , Animais , Humanos , Fibrose Pulmonar Idiopática/metabolismo , Síndrome de Laron/metabolismo , Pulmão/metabolismo , Camundongos , Células-Tronco/metabolismo
18.
JCI Insight ; 4(6)2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30763282

RESUMO

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with unremitting extracellular matrix deposition, leading to a distortion of pulmonary architecture and impaired gas exchange. Fibroblasts from IPF patients acquire an invasive phenotype that is essential for progressive fibrosis. Here, we performed RNA sequencing analysis on invasive and noninvasive fibroblasts and found that the immune checkpoint ligand CD274 (also known as PD-L1) was upregulated on invasive lung fibroblasts and was required for the invasive phenotype of lung fibroblasts, is regulated by p53 and FAK, and drives lung fibrosis in a humanized IPF model in mice. Activating CD274 in IPF fibroblasts promoted invasion in vitro and pulmonary fibrosis in vivo. CD274 knockout in IPF fibroblasts and targeting CD274 by FAK inhibition or CD274-neutralizing antibodies blunted invasion and attenuated fibrosis, suggesting that CD274 may be a novel therapeutic target in IPF.


Assuntos
Antígeno B7-H1/metabolismo , Fibroblastos/metabolismo , Fibrose/metabolismo , Fibrose Pulmonar Idiopática/metabolismo , Animais , Antígeno B7-H1/genética , Adesão Celular , Feminino , Fibroblastos/patologia , Fibrose/patologia , Humanos , Fibrose Pulmonar Idiopática/patologia , Fibrose Pulmonar Idiopática/terapia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Fenótipo , Transcriptoma
19.
Cell Rep ; 22(13): 3625-3640, 2018 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-29590628

RESUMO

Fibroblast heterogeneity has long been recognized in mouse and human lungs, homeostasis, and disease states. However, there is no common consensus on fibroblast subtypes, lineages, biological properties, signaling, and plasticity, which severely hampers our understanding of the mechanisms of fibrosis. To comprehensively classify fibroblast populations in the lung using an unbiased approach, single-cell RNA sequencing was performed with mesenchymal preparations from either uninjured or bleomycin-treated mouse lungs. Single-cell transcriptome analyses classified and defined six mesenchymal cell types in normal lung and seven in fibrotic lung. Furthermore, delineation of their differentiation trajectory was achieved by a machine learning method. This collection of single-cell transcriptomes and the distinct classification of fibroblast subsets provide a new resource for understanding the fibroblast landscape and the roles of fibroblasts in fibrotic diseases.


Assuntos
Fibroblastos/patologia , Fibrose Pulmonar/patologia , Animais , Diferenciação Celular/fisiologia , Células Cultivadas , Modelos Animais de Doenças , Fibroblastos/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fibrose Pulmonar/metabolismo , Análise de Célula Única
20.
Matrix Biol ; 55: 35-48, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26987798

RESUMO

Dysregulated repair of lung injury often results in lung fibrosis characterized by unremitting deposition of matrix components including glycosaminoglycan hyaluronan (HA). HA is mainly produced by hyaluronan synthases (HAS) in mesenchymal cells. We previously demonstrated that over-expression of HAS2 in mesenchymal cells in mice regulates the invasiveness of fibroblasts and promotes severe lung fibrosis. The mechanisms that control the resolution of lung fibrosis are unknown. We propose that a critical step in resolving fibrosis is the induction of senescence in fibrotic fibroblasts and hyaluronan synthase 2 may regulate this process. We found that fibrotic fibroblasts developed the characteristics of replicative senescence in culture and that HAS2 expression was dramatically down-regulated. Furthermore, down-regulation of HAS2 initiated and regulated fibroblast senescence through a p27-CDK2-SKP2 pathway. Deletion of HAS2 in mouse mesenchymal cells increased the cellular senescence of fibroblasts in bleomycin-induced mouse lung fibrosis in vivo. These data suggest that HAS2 may be a critical regulator of the fate of pulmonary fibrosis and we propose a model where over-expression of HAS2 promotes an invasive phenotype resulting in severe fibrosis and down-regulation of HAS2 promotes resolution. Targeting HAS2 to induce fibroblast senescence could be an attractive approach to resolve tissue fibrosis.


Assuntos
Senescência Celular , Fibroblastos/enzimologia , Hialuronan Sintases/metabolismo , Fibrose Pulmonar/enzimologia , Animais , Células Cultivadas , Humanos , Camundongos Transgênicos , Fibrose Pulmonar/patologia
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