Regulation of mucin gene expression in human tracheobronchial epithelial cells by thyroid hormone

We reported previously that the expression of the gene encoding MUC5AC mucin in human airway epithelial cells is controlled by retinoic acid via the retinoic acid receptor (RAR)-α and that 3,3′,5-tri-iodothyronine (T3) inhibits the expression of MUC5AC. The purpose of the present study was to identify mechanisms mediating the effect of T3. T3 has been shown to inhibit gene expression via several mechanisms, either by enhancing or repressing the transcription of target genes or by the regulation of post-transcriptional events. Results showed that T3 strongly inhibited MUC5AC-driven luciferase activity in normal human tracheobronchial epithelial cells that had been transiently transfected with a MUC5AC–luciferase reporter construct; however, it did not affect MUC5AC mRNA stability. These results indicate that T3 suppresses MUC5AC expression at the transcriptional level. An analysis of deletion constructs showed that deletion of the region downstream of 3kb resulted in markedly decreased levels of MUC5AC transcription in the absence of T3 (i.e. under control conditions) as well as a loss of responsiveness to the inhibitory effects of T3. This suggests that this region might contain elements important for the activation as well as the repression of MUC5AC transcription. To determine whether T3 modulates retinoic-acid-dependent MUC5AC transcription via an alteration in the abundance of retinoid receptor proteins, we examined the type and abundance of these receptors in nuclear extracts of airway epithelial cells grown in the presence or absence of T3. Western blots showed that T3 markedly decreased several types of retinoid receptor while not affecting T3 receptor proteins. Consistent with this finding were gel-shift assays revealing a decrease in RAR–retinoic acid response element complexes obtained from T3-treated cells. We propose that T3 might inhibit retinoid-dependent MUC5AC expression by decreasing retinoid receptor levels and thereby decreasing the transcriptional activation of this gene for mucins.

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Mechanism of dexamethasone-mediated interleukin-8 gene suppression in cultured airway epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2001.280.1.l107 ◽

2001 ◽

Vol 280 (1) ◽

pp. L107-L115 ◽

Cited By ~ 36

Author(s):

Mary Mann-Jong Chang ◽

Maya Juarez ◽

Dallas M. Hyde ◽

Reen Wu

Keyword(s):

Gene Expression ◽

Protein Synthesis ◽

Epithelial Cells ◽

Actinomycin D ◽

Airway Epithelial Cells ◽

Interleukin 8 ◽

Transcriptional Level ◽

Dependent Manner ◽

Airway Epithelial ◽

New Protein

The effects of dexamethasone, a glucocorticoid analog, on interleukin 8 (IL-8) gene expression were studied in cultures of primary human tracheobronchial epithelial cells and an immortalized human bronchial epithelial cell line, HBE1 cells. Dexamethasone inhibited IL-8 mRNA and protein expression in a concentration- and time-dependent manner. The inhibition did not occur at the transcriptional level since both nuclear run-on activity and IL-8 promoter-reporter gene expression assay revealed no significant effect. Instead, there was a change in IL-8 mRNA stability in dexamethasone-treated cultures. Under actinomycin D treatment, IL-8 mRNA was quite stable in dexamethasone-depleted cultures, while in dexamethasone-pretreated cultures, IL-8 message was rapidly degraded within the first hour, then leveled off. When dexamethasone and actinomycin D were added simultaneously to dexamethasone-depleted cultures, IL-8 mRNA remained rather stable. When cycloheximide was used to inhibit new protein synthesis, dexamethasone-dependent inhibition was not observed. These results suggest that a posttranscriptional mechanism, which requires dexamethasone-dependent new protein synthesis, is involved in the regulation of IL-8 mRNA by dexamethasone in airway epithelial cells.

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Somatic cell hemoglobin modulates nitrogen oxide metabolism in the human airway epithelium

Scientific Reports ◽

10.1038/s41598-021-94782-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Nadzeya Marozkina ◽

Laura Smith ◽

Yi Zhao ◽

Joe Zein ◽

James F. Chmiel ◽

...

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Nitrogen Oxides ◽

Airway Epithelium ◽

Airflow Obstruction ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Human Airway ◽

Human Airway Epithelium ◽

Human Airway Epithelial Cells

AbstractEndothelial hemoglobin (Hb)α regulates endothelial nitric oxide synthase (eNOS) biochemistry. We hypothesized that Hb could also be expressed and biochemically active in the ciliated human airway epithelium. Primary human airway epithelial cells, cultured at air–liquid interface (ALI), were obtained by clinical airway brushings or from explanted lungs. Human airway Hb mRNA data were from publically available databases; or from RT-PCR. Hb proteins were identified by immunoprecipitation, immunoblot, immunohistochemistry, immunofluorescence and liquid chromatography- mass spectrometry. Viral vectors were used to alter Hbβ expression. Heme and nitrogen oxides were measured colorimetrically. Hb mRNA was expressed in human ciliated epithelial cells. Heme proteins (Hbα, β, and δ) were detected in ALI cultures by several methods. Higher levels of airway epithelial Hbβ gene expression were associated with lower FEV1 in asthma. Both Hbβ knockdown and overexpression affected cell morphology. Hbβ and eNOS were apically colocalized. Binding heme with CO decreased extracellular accumulation of nitrogen oxides. Human airway epithelial cells express Hb. Higher levels of Hbβ gene expression were associated with airflow obstruction. Hbβ and eNOS were colocalized in ciliated cells, and heme affected oxidation of the NOS product. Epithelial Hb expression may be relevant to human airways diseases.

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Exploring host-pathogen interactions at the epithelial surface: application of transcriptomics in lung biology

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00242.2006 ◽

2007 ◽

Vol 292 (2) ◽

pp. L367-L377 ◽

Cited By ~ 6

Author(s):

Joost B. Vos ◽

Nicole A. Datson ◽

Klaus F. Rabe ◽

Pieter S. Hiemstra

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Large Scale ◽

Brain Research ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Host Pathogen Interactions ◽

Epithelial Surface ◽

Complex Interactions ◽

Host Pathogen

The epithelial surface of the airways is the largest barrier-forming interface between the human body and the outside world. It is now well recognized that, at this strategic position, airway epithelial cells play an eminent role in host defense by recognizing and responding to microbial exposure. Conversely, inhaled microorganisms also respond to contact with epithelial cells. Our understanding of this cross talk is limited, requiring sophisticated experimental approaches to analyze these complex interactions. High-throughput technologies, such as DNA microarray analysis and serial analysis of gene expression (SAGE), have been developed to screen for gene expression levels at large scale within single experiments. Since their introduction, these hypothesis-generating technologies have been widely used in diverse areas such as oncology and brain research. Successful application of these genomics-based technologies has also revealed novel insights in host-pathogen interactions in both the host and pathogen. This review aims to provide an overview of the SAGE and microarray technology illustrated by their application in the analysis of host-pathogen interactions. In particular, the interactions between epithelial cells in the human lungs and clinically relevant microorganisms are the central focus of this review.

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Recent Advances in Molecular Biology of Human Bocavirus 1 and Its Applications

Frontiers in Microbiology ◽

10.3389/fmicb.2021.696604 ◽

2021 ◽

Vol 12 ◽

Author(s):

Liting Shao ◽

Weiran Shen ◽

Shengqi Wang ◽

Jianming Qiu

Keyword(s):

Gene Expression ◽

Dna Repair ◽

Epithelial Cells ◽

Airway Epithelial Cells ◽

Structural Proteins ◽

Human Bocavirus ◽

Airway Epithelial ◽

Raav Vector ◽

Human Airway ◽

Non Coding Rna

Human bocavirus 1 (HBoV1) was discovered in human nasopharyngeal specimens in 2005. It is an autonomous human parvovirus and causes acute respiratory tract infections in young children. HBoV1 infects well differentiated or polarized human airway epithelial cells in vitro. Unique among all parvoviruses, HBoV1 expresses 6 non-structural proteins, NS1, NS1-70, NS2, NS3, NS4, and NP1, and a viral non-coding RNA (BocaSR), and three structural proteins VP1, VP2, and VP3. The BocaSR is the first identified RNA polymerase III (Pol III) transcribed viral non-coding RNA in small DNA viruses. It plays an important role in regulation of viral gene expression and a direct role in viral DNA replication in the nucleus. HBoV1 genome replication in the polarized/non-dividing airway epithelial cells depends on the DNA damage and DNA repair pathways and involves error-free Y-family DNA repair DNA polymerase (Pol) η and Pol κ. Importantly, HBoV1 is a helper virus for the replication of dependoparvovirus, adeno-associated virus (AAV), in polarized human airway epithelial cells, and HBoV1 gene products support wild-type AAV replication and recombinant AAV (rAAV) production in human embryonic kidney (HEK) 293 cells. More importantly, the HBoV1 capsid is able to pseudopackage an rAAV2 or rHBoV1 genome, producing the rAAV2/HBoV1 or rHBoV1 vector. The HBoV1 capsid based rAAV vector has a high tropism for human airway epithelia. A deeper understanding in HBoV1 replication and gene expression will help find a better way to produce the rAAV vector and to increase the efficacy of gene delivery using the rAAV2/HBoV1 or rHBoV1 vector, in particular, to human airways. This review summarizes the recent advances in gene expression and replication of HBoV1, as well as the use of HBoV1 as a parvoviral vector for gene delivery.

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