scholarly journals The Lung Elastin Matrix Undergoes Rapid Degradation Upon Adult Loss of Hox5 Function

2021 ◽  
Vol 9 ◽  
Author(s):  
Mu-Hang Li ◽  
Leilani M. Marty-Santos ◽  
Paul R. van Ginkel ◽  
Aubrey E. McDermott ◽  
Andrew J. Rasky ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Lung Development ◽  
Lung Fibroblasts ◽  
Loss Of Function ◽  
Specific Loss ◽  
Skeletal Patterning ◽  
The Matrix ◽  
Distal Lung ◽  
And Function ◽  
Matrix Metalloproteinase 12

Hox genes encode transcription factors that are critical for embryonic skeletal patterning and organogenesis. The Hoxa5, Hoxb5, and Hoxc5 paralogs are expressed in the lung mesenchyme and function redundantly during embryonic lung development. Conditional loss-of-function of these genes during postnatal stages leads to severe defects in alveologenesis, specifically in the generation of the elastin network, and animals display bronchopulmonary dysplasia (BPD) or BPD-like phenotype. Here we show the surprising results that mesenchyme-specific loss of Hox5 function at adult stages leads to rapid disruption of the mature elastin matrix, alveolar enlargement, and an emphysema-like phenotype. As the elastin matrix of the lung is considered highly stable, adult disruption of the matrix was not predicted. Just 2 weeks after deletion, adult Hox5 mutant animals show significant increases in alveolar space and changes in pulmonary function, including reduced elastance and increased compliance. Examination of the extracellular matrix (ECM) of adult Tbx4rtTA; TetOCre; Hox5afafbbcc lungs demonstrates a disruption of the elastin network although the underlying fibronectin, interstitial collagen and basement membrane appear unaffected. An influx of macrophages and increased matrix metalloproteinase 12 (MMP12) are observed in the distal lung 3 days after Hox5 deletion. In culture, fibroblasts from Hox5 mutant lungs exhibit reduced adhesion. These findings establish a novel role for Hox5 transcription factors as critical regulators of lung fibroblasts at adult homeostasis.

scholarly journals Loss of Fas-signaling in pro-fibrotic fibroblasts impairs homeostatic fibrosis resolution and promotes persistent pulmonary fibrosis

2020 ◽  
Author(s):  
Elizabeth F. Redente ◽  
Sangeeta Chakraborty ◽  
Satria Sajuthi ◽  
Bart P. Black ◽  
Benjamin L. Edelman ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Lung Fibroblast ◽  
Lung Fibroblasts ◽  
Normal Lung ◽  
Loss Of Function ◽  
Fas Signaling ◽  
Distal Lung ◽  
Induced Apoptosis

ABSTRACTIdiopathic pulmonary fibrosis (IPF) is a progressive, irreversible fibrotic disease of the distal lung alveoli that culminates in respiratory failure and reduced lifespan. Unlike normal lung repair in response to injury, IPF is associated with the accumulation and persistence of fibroblasts and myofibroblasts and continued production of collagen and other extracellular matrix (ECM) components. Prior in vitro studies have led to the hypothesis that the development of resistance to Fas-induced apoptosis by lung fibroblasts and myofibroblasts contibributes to their accumulation in the distal lung tissues of IPF patients. Here, we test this hypothesis in vivo in the resolving model of bleomycin-induced pulmonary fibrosis in mice. Using genetic loss-of-function approaches to inhibit Fas signaling in fibroblasts, novel flow cytometry strategies to quantify lung fibroblast subsets and transcriptional profiling of lung fibroblasts by bulk and single cell RNA-sequencing, we show that Fas is necessary for lung fibroblast apoptosis during homeostatic resolution of bleomycin-induced pulmonary fibrosis in vivo. Furthermore, we show that loss of Fas signaling leads to the persistence and continued pro-fibrotic functions of lung fibroblasts. Our studies provide novel insights into the mechanisms that contribute to fibroblast survival, persistence and continued ECM deposition in the context of IPF and how failure to undergo Fas-induced apoptosis prevents fibrosis resolution.

scholarly journals WNT5a-ROR Signaling Is Essential for Alveologenesis

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 384 ◽  
Author(s):  
Changgong Li ◽  
Susan M Smith ◽  
Neil Peinado ◽  
Feng Gao ◽  
Wei Li ◽  
...  
Keyword(s):  
Lung Development ◽  
Lung Fibroblasts ◽  
Chronic Obstructive ◽  
Type I ◽  
Loss Of Function ◽  
Obstructive Pulmonary Disease ◽  
Alveolar Epithelial ◽  
Isolated Lung ◽  
And Migration

WNT5a is a mainly “non-canonical” WNT ligand whose dysregulation is observed in lung diseases such as idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and asthma. Germline deletion of Wnt5a disrupts embryonic lung development. However, the temporal-specific function of WNT5a remains unknown. In this study, we generated a conditional loss-of-function mouse model (Wnt5aCAG) and examined the specific role of Wnt5a during the saccular and alveolar phases of lung development. The lack of Wnt5a in the saccular phase blocked distal airway expansion and attenuated differentiation of endothelial and alveolar epithelial type I (AT1) cells and myofibroblasts. Postnatal Wnt5a inactivation disrupted alveologenesis, producing a phenotype resembling human bronchopulmonary dysplasia (BPD). Mutant lungs showed hypoalveolization, but endothelial and epithelial differentiation was unaffected. The major impact of Wnt5a inactivation on alveologenesis was on myofibroblast differentiation and migration, with reduced expression of key regulatory genes. These findings were validated in vitro using isolated lung fibroblasts. Conditional inactivation of the WNT5a receptors Ror1 and Ror2 in alveolar myofibroblasts recapitulated the Wnt5aCAG phenotype, demonstrating that myofibroblast defects are the major cause of arrested alveologenesis in Wnt5aCAG lungs. Finally, we show that WNT5a is reduced in human BPD lung samples, indicating the clinical relevance and potential role for WNT5a in pathogenesis of BPD.

scholarly journals Runx transcription factors in the development and function of the definitive hematopoietic system

Blood ◽  
2017 ◽  
Vol 129 (15) ◽  
pp. 2061-2069 ◽  
Author(s):  
Marella de Bruijn ◽  
Elaine Dzierzak
Keyword(s):  
Transcription Factors ◽  
Current Knowledge ◽  
Biological Effects ◽  
Regulation Of Gene Expression ◽  
Loss Of Function ◽  
Specific Expression ◽  
Hematopoietic Stem ◽  
Hematopoietic Development ◽  
Cell Lineages ◽  
And Function

AbstractThe Runx family of transcription factors (Runx1, Runx2, and Runx3) are highly conserved and encode proteins involved in a variety of cell lineages, including blood and blood-related cell lineages, during developmental and adult stages of life. They perform activation and repressive functions in the regulation of gene expression. The requirement for Runx1 in the normal hematopoietic development and its dysregulation through chromosomal translocations and loss-of-function mutations as found in acute myeloid leukemias highlight the importance of this transcription factor in the healthy blood system. Whereas another review will focus on the role of Runx factors in leukemias, this review will provide an overview of the normal regulation and function of Runx factors in hematopoiesis and focus particularly on the biological effects of Runx1 in the generation of hematopoietic stem cells. We will present the current knowledge of the structure and regulatory features directing lineage-specific expression of Runx genes, the models of embryonic and adult hematopoietic development that provide information on their function, and some of the mechanisms by which they affect hematopoietic function.

scholarly journals Neuronal dystonin isoform 2 is a mediator of endoplasmic reticulum structure and function

2012 ◽  
Vol 23 (4) ◽  
pp. 553-566 ◽  
Author(s):  
Scott D. Ryan ◽  
Andrew Ferrier ◽  
Tadasu Sato ◽  
Ryan W. O'Meara ◽  
Yves De Repentigny ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Sensory Neurons ◽  
Stress Proteins ◽  
Function Analysis ◽  
Structure And Function ◽  
Loss Of Function ◽  
Specific Loss ◽  
And Function

Dystonin/Bpag1 is a cytoskeletal linker protein whose loss of function in dystonia musculorum (dt) mice results in hereditary sensory neuropathy. Although loss of expression of neuronal dystonin isoforms (dystonin-a1/dystonin-a2) is sufficient to cause dt pathogenesis, the diverging function of each isoform and what pathological mechanisms are activated upon their loss remains unclear. Here we show that dt27 mice manifest ultrastructural defects at the endoplasmic reticulum (ER) in sensory neurons corresponding to in vivo induction of ER stress proteins. ER stress subsequently leads to sensory neurodegeneration through induction of a proapoptotic caspase cascade. dt sensory neurons display neurodegenerative pathologies, including Ca2+ dyshomeostasis, unfolded protein response (UPR) induction, caspase activation, and apoptosis. Isoform-specific loss-of-function analysis attributes these neurodegenerative pathologies to specific loss of dystonin-a2. Inhibition of either UPR or caspase signaling promotes the viability of cells deficient in dystonin. This study provides insight into the mechanism of dt neuropathology and proposes a role for dystonin-a2 as a mediator of normal ER structure and function.

Dexamethasone and epinephrine stimulate surfactant secretion in type II cells of embryonic chickens

2001 ◽  
Vol 281 (3) ◽  
pp. R770-R777 ◽  
Author(s):  
Lucy C. Sullivan ◽  
Sandra Orgeig
Keyword(s):  
Lung Development ◽  
Pulmonary Surfactant ◽  
Egg Laying ◽  
Lung Fibroblasts ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lung Structure ◽  
Cellular Pathways ◽  
And Function

Pulmonary surfactant (PS), a mixture of phospholipids and proteins secreted by alveolar type II cells, functions to reduce the surface tension in the lungs of all air-breathing vertebrates. Here we examine the control of PS during lung development in a homeothermic egg-laying vertebrate. In mammals, glucocorticoids and autonomic neurotransmitters contribute to the maturation of the surfactant system. We examined whether dexamethasone, epinephrine, and carbamylcholine hydrochloride (agonist for acetylcholine) increased the amount of PS secreted from cultured type II cells of the developing chicken lung. In particular, we wanted to establish whether dexamethasone would increase PS secretion through a process involving lung fibroblasts. We isolated and cocultured type II cells and lung fibroblasts from chickens after 16, 18, and 20 days of incubation and from hatchlings ( day 21). Epinephrine stimulated phosphatidylcholine (PC) secretion at all stages, whereas dexamethasone stimulated secretion of PC at days 16 and 18. Carbamylcholine hydrochloride had no effect at any stage. This is the first study to establish the existence of similar cellular pathways regulating the development of surfactant in chickens and eutherian mammals, despite the vastly different birthing strategies and lung structure and function.

scholarly journals Genetic Testing for Neonatal Respiratory Disease

Children ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 216
Author(s):  
Lawrence M. Nogee ◽  
Rita M. Ryan
Keyword(s):  
Transcription Factors ◽  
Genetic Testing ◽  
Lung Disease ◽  
Immune Regulation ◽  
Lung Development ◽  
Disease Genes ◽  
Specific Diagnosis ◽  
Neonatal Lung ◽  
Genetic Mechanisms ◽  
And Function

Genetic mechanisms are now recognized as rare causes of neonatal lung disease. Genes potentially responsible for neonatal lung disease include those encoding proteins important in surfactant function and metabolism, transcription factors important in lung development, proteins involved in ciliary assembly and function, and various other structural and immune regulation genes. The phenotypes of infants with genetic causes of neonatal lung disease may have some features that are difficult to distinguish clinically from more common, reversible causes of lung disease, and from each other. Multigene panels are now available that can allow for a specific diagnosis, providing important information for treatment and prognosis. This review discusses genes in which abnormalities are known to cause neonatal lung disease and their associated phenotypes, and advantages and limitations of genetic testing.

scholarly journals Alterations in ZnT1 expression and function lead to impaired intracellular zinc homeostasis in cancer

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Adrian Israel Lehvy ◽  
Guy Horev ◽  
Yarden Golan ◽  
Fabian Glaser ◽  
Yael Shammai ◽  
...  
Keyword(s):  
Malignant Tumors ◽  
Zinc Homeostasis ◽  
Healthy Population ◽  
Missense Mutations ◽  
Protein Alignment ◽  
Loss Of Function ◽  
Intracellular Zinc ◽  
Dismal Prognosis ◽  
Zinc Levels ◽  
And Function

Abstract Zinc is vital for the structure and function of ~3000 human proteins and hence plays key physiological roles. Consequently, impaired zinc homeostasis is associated with various human diseases including cancer. Intracellular zinc levels are tightly regulated by two families of zinc transporters: ZIPs and ZnTs; ZIPs import zinc into the cytosol from the extracellular milieu, or from the lumen of organelles into the cytoplasm. In contrast, the vast majority of ZnTs compartmentalize zinc within organelles, whereas the ubiquitously expressed ZnT1 is the sole zinc exporter. Herein, we explored the hypothesis that qualitative and quantitative alterations in ZnT1 activity impair cellular zinc homeostasis in cancer. Towards this end, we first used bioinformatics to analyze inactivating mutations in ZIPs and ZNTs, catalogued in the COSMIC and gnomAD databases, representing tumor specimens and healthy population controls, respectively. ZnT1, ZnT10, ZIP8, and ZIP10 showed extremely high rates of loss of function mutations in cancer as compared to healthy controls. Analysis of the putative functional impact of missense mutations in ZnT1-ZnT10 and ZIP1-ZIP14, using homologous protein alignment and structural predictions, revealed that ZnT1 displays a markedly increased frequency of predicted functionally deleterious mutations in malignant tumors, as compared to a healthy population. Furthermore, examination of ZnT1 expression in 30 cancer types in the TCGA database revealed five tumor types with significant ZnT1 overexpression, which predicted dismal prognosis for cancer patient survival. Novel functional zinc transport assays, which allowed for the indirect measurement of cytosolic zinc levels, established that wild type ZnT1 overexpression results in low intracellular zinc levels. In contrast, overexpression of predicted deleterious ZnT1 missense mutations did not reduce intracellular zinc levels, validating eight missense mutations as loss of function (LoF) mutations. Thus, alterations in ZnT1 expression and LoF mutations in ZnT1 provide a molecular mechanism for impaired zinc homeostasis in cancer formation and/or progression.

scholarly journals The NALCN Channel Regulator UNC-80 Functions in a Subset of Interneurons To Regulate Caenorhabditis elegans Reversal Behavior

2019 ◽  
Vol 10 (1) ◽  
pp. 199-210 ◽  
Author(s):  
Chuanman Zhou ◽  
Jintao Luo ◽  
Xiaohui He ◽  
Qian Zhou ◽  
Yunxia He ◽  
...  
Keyword(s):  
Plant Hormone ◽  
Neuronal Excitability ◽  
Resting Membrane Potential ◽  
Loss Of Function ◽  
Wild Type ◽  
C Elegans ◽  
Link Type ◽  
Complex Functions ◽  
And Function ◽  
Multiple Loss

NALCN (Na+leak channel, non-selective) is a conserved, voltage-insensitive cation channel that regulates resting membrane potential and neuronal excitability. UNC79 and UNC80 are key regulators of the channel function. However, the behavioral effects of the channel complex are not entirely clear and the neurons in which the channel functions remain to be identified. In a forward genetic screen for C. elegans mutants with defective avoidance response to the plant hormone methyl salicylate (MeSa), we isolated multiple loss-of-function mutations in unc-80 and unc-79. C. elegans NALCN mutants exhibited similarly defective MeSa avoidance. Interestingly, NALCN, unc-80 and unc-79 mutants all showed wild type-like responses to other attractive or repelling odorants, suggesting that NALCN does not broadly affect odor detection or related forward and reversal behaviors. To understand in which neurons the channel functions, we determined the identities of a subset of unc-80-expressing neurons. We found that unc-79 and unc-80 are expressed and function in overlapping neurons, which verified previous assumptions. Neuron-specific transgene rescue and knockdown experiments suggest that the command interneurons AVA and AVE and the anterior guidepost neuron AVG can play a sufficient role in mediating unc-80 regulation of the MeSa avoidance. Though primarily based on genetic analyses, our results further imply that MeSa might activate NALCN by direct or indirect actions. Altogether, we provide an initial look into the key neurons in which the NALCN channel complex functions and identify a novel function of the channel in regulating C. elegans reversal behavior through command interneurons.

scholarly journals NKL Homeobox Gene VENTX Is Part of a Regulatory Network in Human Conventional Dendritic Cells

2021 ◽  
Vol 22 (11) ◽  
pp. 5902
Author(s):  
Stefan Nagel ◽  
Claudia Pommerenke ◽  
Corinna Meyer ◽  
Hans G. Drexler
Keyword(s):  
Dendritic Cells ◽  
Transcription Factors ◽  
Cell Lines ◽  
Expression Profiling ◽  
Regulatory Network ◽  
Homeobox Gene ◽  
Leukemia Cell Line ◽  
Specific Gene ◽  
Rna Seq ◽  
And Function

Recently, we documented a hematopoietic NKL-code mapping physiological expression patterns of NKL homeobox genes in human myelopoiesis including monocytes and their derived dendritic cells (DCs). Here, we enlarge this map to include normal NKL homeobox gene expressions in progenitor-derived DCs. Analysis of public gene expression profiling and RNA-seq datasets containing plasmacytoid and conventional dendritic cells (pDC and cDC) demonstrated HHEX activity in both entities while cDCs additionally expressed VENTX. The consequent aim of our study was to examine regulation and function of VENTX in DCs. We compared profiling data of VENTX-positive cDC and monocytes with VENTX-negative pDC and common myeloid progenitor entities and revealed several differentially expressed genes encoding transcription factors and pathway components, representing potential VENTX regulators. Screening of RNA-seq data for 100 leukemia/lymphoma cell lines identified prominent VENTX expression in an acute myelomonocytic leukemia cell line, MUTZ-3 containing inv(3)(q21q26) and t(12;22)(p13;q11) and representing a model for DC differentiation studies. Furthermore, extended gene analyses indicated that MUTZ-3 is associated with the subtype cDC2. In addition to analysis of public chromatin immune-precipitation data, subsequent knockdown experiments and modulations of signaling pathways in MUTZ-3 and control cell lines confirmed identified candidate transcription factors CEBPB, ETV6, EVI1, GATA2, IRF2, MN1, SPIB, and SPI1 and the CSF-, NOTCH-, and TNFa-pathways as VENTX regulators. Live-cell imaging analyses of MUTZ-3 cells treated for VENTX knockdown excluded impacts on apoptosis or induced alteration of differentiation-associated cell morphology. In contrast, target gene analysis performed by expression profiling of knockdown-treated MUTZ-3 cells revealed VENTX-mediated activation of several cDC-specific genes including CSFR1, EGR2, and MIR10A and inhibition of pDC-specific genes like RUNX2. Taken together, we added NKL homeobox gene activities for progenitor-derived DCs to the NKL-code, showing that VENTX is expressed in cDCs but not in pDCs and forms part of a cDC-specific gene regulatory network operating in DC differentiation and function.

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