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Dare A, King SD, Chen SY. Surfactant protein A promotes western diet-induced hepatic steatosis and fibrosis in mice. Sci Rep 2024; 14:7464. [PMID: 38553537 PMCID: PMC10980756 DOI: 10.1038/s41598-024-58291-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Accepted: 03/27/2024] [Indexed: 04/02/2024] Open
Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) remains the most common cause of liver disease in the United States due to the increased incidence of metabolic dysfunction and obesity. Surfactant protein A (SPA) regulates macrophage function, strongly binds to lipids, and is implicated in renal and idiopathic pulmonary fibrosis (IPF). However, the role of SPA in lipid accumulation, inflammation, and hepatic fibrosis that characterize MASLD remains unknown. SPA deficient (SPA-/-) and age-matched wild-type (WT) control mice were fed a Western diet for 8 weeks to induce MASLD. Blood and liver samples were collected and used to analyze pathological features associated with MASLD. SPA expression was significantly upregulated in livers of mice with MASLD. SPA deficiency attenuated lipid accumulation along with downregulation of genes involved in fatty acid uptake and reduction of hepatic inflammation as evidenced by the diminished macrophage activation, decreased monocyte infiltration, and reduced production of inflammatory cytokines. Moreover, SPA-/- inhibited stellate cell activation, collagen deposit, and liver fibrosis. These results highlight the novel role of SPA in promoting fatty acid uptake into hepatocytes, causing excessive lipid accumulation, inflammation, and fibrosis implicated in the pathogenesis of MASLD.
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Affiliation(s)
- Ayobami Dare
- Department of Surgery, University of Missouri School of Medicine, 1 Hospital Drive, Columbia, MO, 65212, USA
| | - Skylar D King
- Department of Surgery, University of Missouri School of Medicine, 1 Hospital Drive, Columbia, MO, 65212, USA
| | - Shi-You Chen
- Department of Surgery, University of Missouri School of Medicine, 1 Hospital Drive, Columbia, MO, 65212, USA.
- The Research Service, Harry S. Truman Memorial Veterans Hospital, Columbia, MO, 65201, USA.
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Abdel Megeid AK, Refeat MM, Ashaat EA, El-Kamah G, El-Saiedi SA, Elfalaki MM, El Ruby MO, Amr KS. Correlating SFTPC gene variants to interstitial lung disease in Egyptian children. J Genet Eng Biotechnol 2022; 20:117. [PMID: 35939165 PMCID: PMC9360361 DOI: 10.1186/s43141-022-00399-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 07/10/2022] [Indexed: 01/04/2023]
Abstract
Background Interstitial lung disease (ILD) is a broad heterogeneous group of lung disorders that is characterized by inflammation of the lungs. Surfactant dysfunction disorders are a rare form of ILD diseases that result from mutations in surfactant protein C gene (SFTPC) with prevalence of approximately 1/1.7 million births. SFTPC patients are presented with clinical manifestations of ILD ranging from fatal respiratory failure of newborn to chronic respiratory problems in children. In the current study, we aimed to investigate the spectrum of SFTPC genetic variants as well as the correlation of the SFTPC gene mutations with ILD disease in twenty unrelated Egyptian children with diffuse lung disease and suspected surfactant dysfunction using Sanger sequencing. Results Sequencing of SFTPC gene revealed five variants: c.42+35G>A (IVS1+35G>A) (rs8192340) and c.43-21T>C (IVS1-21T>C) (rs13248346) in intron 1, c.436-8C>G (IVS4-8C>G) (rs2070687) in intron 4, c.413C>A p.T138N (rs4715) in exon 4, and c.557G>Ap.S186N (rs1124) in exon 5. Conclusion The present study confirms the association of detecting variants of SFTPC with surfactant dysfunction disorders.
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Affiliation(s)
| | - Miral M Refeat
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Engy A Ashaat
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Ghada El-Kamah
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | | | | | - Mona O El Ruby
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Khalda S Amr
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt.
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Whitsett JA, Wert SE, Weaver TE. Diseases of pulmonary surfactant homeostasis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2015; 10:371-93. [PMID: 25621661 DOI: 10.1146/annurev-pathol-012513-104644] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Advances in physiology and biochemistry have provided fundamental insights into the role of pulmonary surfactant in the pathogenesis and treatment of preterm infants with respiratory distress syndrome. Identification of the surfactant proteins, lipid transporters, and transcriptional networks regulating their expression has provided the tools and insights needed to discern the molecular and cellular processes regulating the production and function of pulmonary surfactant prior to and after birth. Mutations in genes regulating surfactant homeostasis have been associated with severe lung disease in neonates and older infants. Biophysical and transgenic mouse models have provided insight into the mechanisms underlying surfactant protein and alveolar homeostasis. These studies have provided the framework for understanding the structure and function of pulmonary surfactant, which has informed understanding of the pathogenesis of diverse pulmonary disorders previously considered idiopathic. This review considers the pulmonary surfactant system and the genetic causes of acute and chronic lung disease caused by disruption of alveolar homeostasis.
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Affiliation(s)
- Jeffrey A Whitsett
- Divisions of Neonatology, Perinatal Biology, and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229; , ,
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Kropski JA, Blackwell TS, Loyd JE. The genetic basis of idiopathic pulmonary fibrosis. Eur Respir J 2015; 45:1717-27. [PMID: 25837031 DOI: 10.1183/09031936.00163814] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 03/17/2015] [Indexed: 02/06/2023]
Abstract
Throughout the past decade, there have been substantial advances in understanding the pathogenesis of idiopathic pulmonary fibrosis (IPF). Recently, several large genome-wide association and linkage studies have identified common genetic variants in more than a dozen loci that appear to contribute to IPF risk. In addition, family-based studies have led to the identification of rare genetic variants in genes related to surfactant function and telomere biology, and mechanistic studies suggest pathophysiological derangements associated with these rare genetic variants are also found in sporadic cases of IPF. Current evidence suggests that rather than existing as distinct syndromes, sporadic and familial cases of IPF (familial interstitial pneumonia) probably reflect a continuum of genetic risk. Rapidly evolving bioinformatic and molecular biology techniques, combined with next-generation sequencing technologies, hold great promise for developing a comprehensive, integrated approach to defining the fundamental molecular mechanisms that underlie IPF pathogenesis.
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Affiliation(s)
- Jonathan A Kropski
- Division of Allergy, Pulmonary and Critical Care Medicine, Dept of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Timothy S Blackwell
- Division of Allergy, Pulmonary and Critical Care Medicine, Dept of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA Dept of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA Dept of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA Department of Veterans Affairs Medical Center, Nashville, TN, USA
| | - James E Loyd
- Division of Allergy, Pulmonary and Critical Care Medicine, Dept of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
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Hawkins A, Guttentag SH, Deterding R, Funkhouser WK, Goralski JL, Chatterjee S, Mulugeta S, Beers MF. A non-BRICHOS SFTPC mutant (SP-CI73T) linked to interstitial lung disease promotes a late block in macroautophagy disrupting cellular proteostasis and mitophagy. Am J Physiol Lung Cell Mol Physiol 2014; 308:L33-47. [PMID: 25344067 DOI: 10.1152/ajplung.00217.2014] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mutation of threonine for isoleucine at codon 73 (I73T) in the human surfactant protein C (hSP-C) gene (SFTPC) accounts for a significant portion of SFTPC mutations associated with interstitial lung disease (ILD). Cell lines stably expressing tagged primary translation product of SP-C isoforms were generated to test the hypothesis that deposition of hSP-C(I73T) within the endosomal system promotes disruption of a key cellular quality control pathway, macroautophagy. By fluorescence microscopy, wild-type hSP-C (hSP-C(WT)) colocalized with exogenously expressed human ATP binding cassette class A3 (hABCA3), an indicator of normal trafficking to lysosomal-related organelles. In contrast, hSP-C(I73T) was dissociated from hABCA3 but colocalized to the plasma membrane as well as the endosomal network. Cells expressing hSP-C(I73T) exhibited increases in size and number of cytosolic green fluorescent protein/microtubule-associated protein 1 light-chain 3 (LC3) vesicles, some of which colabeled with red fluorescent protein from the gene dsRed/hSP-C(I73T). By transmission electron microscopy, hSP-C(I73T) cells contained abnormally large autophagic vacuoles containing organellar and proteinaceous debris, which phenocopied ultrastructural changes in alveolar type 2 cells in a lung biopsy from a SFTPC I73T patient. Biochemically, hSP-C(I73T) cells exhibited increased expression of Atg8/LC3, SQSTM1/p62, and Rab7, consistent with a distal block in autophagic vacuole maturation, confirmed by flux studies using bafilomycin A1 and rapamycin. Functionally, hSP-C(I73T) cells showed an impaired degradative capacity for an aggregation-prone huntingtin-1 reporter substrate. The disruption of autophagy-dependent proteostasis was accompanied by increases in mitochondria biomass and parkin expression coupled with a decrease in mitochondrial membrane potential. We conclude that hSP-C(I73T) induces an acquired block in macroautophagy-dependent proteostasis and mitophagy, which could contribute to the increased vulnerability of the lung epithelia to second-hit injury as seen in ILD.
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Affiliation(s)
- Arie Hawkins
- Pulmonary, Allergy, and Critical Care Division, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Susan H Guttentag
- Department of Pediatrics; Monroe Carell Jr. Children's Hospital, Vanderbilt University, Nashville, Tennessee
| | - Robin Deterding
- Department of Pediatrics; University of Colorado School of Medicine, Denver, Colorado
| | - William K Funkhouser
- Department of Pathology and Lab Medicine; University of North Carolina, Chapel Hill, North Carolina
| | - Jennifer L Goralski
- Departments of Medicine and Pediatrics; University of North Carolina, Chapel Hill, North Carolina
| | - Shampa Chatterjee
- Institute for Environmental Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Surafel Mulugeta
- Pulmonary, Allergy, and Critical Care Division, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania;
| | - Michael F Beers
- Pulmonary, Allergy, and Critical Care Division, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania
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Abstract
Advances in the physiology, biochemistry, molecular and cell biology of the pulmonary surfactant system transformed the clinical care and outcome of preterm infants with respiratory distress syndrome. The molecular era of surfactant biology provided genetic insights into the pathogenesis of pulmonary disorders, previously termed 'idiopathic', that affect newborn infants, children and adults. Knowledge related to the structure and function of the surfactant proteins and their roles in alveolar homeostasis has provided new diagnostic, prognostic and therapeutic tools to advance our understanding of the causes and treatments of acute and chronic lung diseases. Severe lung disease in newborn infants and older patients is caused by mutations in genes regulating alveolar epithelial cells and surfactant homeostasis. Mutations in genes encoding the surfactant proteins, transcription factors critical for alveolar morphogenesis and surfactant clearance, are now known to play important roles in the pathogenesis of chronic lung diseases. Identification of the genes underlying the diseases of alveolar homeostasis is useful for the diagnosis of lung disease before and after birth.
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Affiliation(s)
- Jeffrey A Whitsett
- Perinatal Institute, Section of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, and the University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Gardet A, Zheng TS, Viney JL. Genetic architecture of human fibrotic diseases: disease risk and disease progression. Front Pharmacol 2013; 4:159. [PMID: 24391588 PMCID: PMC3866586 DOI: 10.3389/fphar.2013.00159] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 12/03/2013] [Indexed: 12/12/2022] Open
Abstract
Genetic studies of human diseases have identified multiple genetic risk loci for various fibrotic diseases. This has provided insights into the myriad of biological pathways potentially involved in disease pathogenesis. These discoveries suggest that alterations in immune responses, barrier function, metabolism and telomerase activity may be implicated in the genetic risks for fibrotic diseases. In addition to genetic disease-risks, the identification of genetic disease-modifiers associated with disease complications, severity or prognosis provides crucial insights into the biological processes implicated in disease progression. Understanding the biological processes driving disease progression may be critical to delineate more effective strategies for therapeutic interventions. This review provides an overview of current knowledge and gaps regarding genetic disease-risks and genetic disease-modifiers in human fibrotic diseases.
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Oxidative and Endoplasmic Reticulum (ER) Stress in Tissue Fibrosis. CURRENT PATHOBIOLOGY REPORTS 2013. [DOI: 10.1007/s40139-013-0029-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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