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Relationship: 2472
Title
Goblet cell hyperplasia leads to Chronic, Mucus hypersecretion
Upstream event
Downstream event
Key Event Relationship Overview
AOPs Referencing Relationship
Taxonomic Applicability
Sex Applicability
Sex | Evidence |
---|---|
Mixed | Moderate |
Life Stage Applicability
Term | Evidence |
---|---|
All life stages | Moderate |
Key Event Relationship Description
Goblet cell hyperplasia refers to the increase in goblet cell numbers and is a common feature of airway epithelia in asthma and other respiratory diseases. It can arise from sustained proliferation of this cell population following airway injury by, for example, exposure to allergens, pathogens, cigarette smoke and other inhalation exposures (Miyabara et al., 1998; Nagao et al., 2003; Saetta et al., 2000; van Hove et al., 2009; Walter et al., 2002; Hao et al., 2014; Lukacs et al., 2010; Hao et al., 2013; Yageta et al., 2014; Nie et al., 2012; Hegab et al., 2007; Kim et al., 2016). Since goblet cells are mucin-producing cells, an increase in goblet cell numbers consequently equates to an increase (from basal levels) in mucin production. Chronic mucus hypersecretion is also a main feature of chronic lung diseases, and the presence of goblet cell hyperplasia or goblet cell metaplasia in the lungs of chronic obstructive pulmonary disease, asthma and cystic fibrosis patients has been inferred as cause for sustained mucus production (Rose and Voynow, 2006; Munkholm and Mortensen, 2014).
Evidence Collection Strategy
Evidence Supporting this KER
This KER is inferred. However, there is indirect evidence demonstrating an increase in mucin production, which is frequently equated with increased MUC5AC mRNA and protein expression, in the presence of goblet cell hyperplasia as judged by histopathological examination and/or an increase in Alcian Blue/periodic acid Schiff (AB/PAS) and/or MUC5AC-positive antibody staining in airway epithelia following inhalation exposures (Hegab et al., 2007; An et al., 2013; Zhou et al., 2016). Goblet cell hyperplasia and mucin overproduction were also linked experimentally through genetic modification: For example, conditional deletion of Foxa2 in respiratory epithelial cells of the developing mouse lung results in goblet cell hyperplasia in bronchi and bronchioles at post-natal day 16 and later (evidenced by histology), which was accompanied by extensive AB/PAS and MUC5AC staining (Wan et al., 2004). Similarly, conditional expression of Spdef in Clara cells of the conducting airways in mice resulted in goblet cell hyperplasia in the trachea and bronchi and in peripheral airways, including smaller bronchioles that normally lack goblet cells, as shown by AB/PAS and Muc5ac staining (Park et al., 2007).
Biological Plausibility
This KER is inferred. However, that an increase in goblet cell numbers also increases mucin production is highly plausible. Studies in human cells, mice and rats demonstrate that mucin content or MUC5AC mRNA and protein expression increase in the presence of histologically confirmed goblet cell hyperplasia. Because both events are measured in parallel and causal evidence is missing, our confidence is moderate.
Empirical Evidence
Goblet cell hyperplasia has been shown to arise following treatment of human primary airway epithelial cells with IL-13 (Atherton et al., 2003; Tanabe et al., 2011; Mishina et al., 2015), following exposure of mice and rats to cigarette smoke (An et al., 2013; Ning et al., 2013; Xu et al., 2015; Liang et al., 2017), and in mouse models of asthma (Takeyama et al., 2008). Concurrent increases in goblet cell numbers and increased MUC5AC gene and protein expression levels were also reported in lung tissues of asthmatic and COPD patients and nasal polyp tissues (Burgel et al., 2000; Ordonez et al., 2001; Xia et al., 2014). Increases in goblet cell numbers were confirmed by morphometric analysis (enumeration of goblet cells, % PAS-stained area) and correlated with increases in MUC5AC gene and protein expression levels.
Uncertainties and Inconsistencies
In some cases, it appears that authors use the terms "goblet cell hyperplasia" and "goblet cell metaplasia" interchangeably, making the evaluation of the available evidence difficult.
Because goblet cell metaplasia is also a feature of epithelial cell remodeling in the context of wound healing, its appearance can be transient. At least one study indicates that goblet cell hyperplasia is also found in healthy non-smokers (never- and former smokers), where it appears as isolated foci—as opposed to the more extensive involvement of the airway epithelium seen in e.g. COPD patients (Polosukhin et al., 2011).
Known modulating factors
Unknown
Quantitative Understanding of the Linkage
Our quantitative understanding of this KER is limited by the fact that few studies interrogate causality between goblet cell hyperplasia and increased mucin production. To our knoweldge, there is no comprehensive, systematic study of the dose-response relationship. This may be primarily due to the fact that goblet cell hyperplasia is a qualitative finding on histopathological examination and cannot be as easily quantified as, for example, the number of cells that stain positively with an anti-MUC5AC antibody as a marker for mucin production.
Response-response Relationship
In male Sprague-Dawley rats that were whole body exposed to cigarette smoke of 10 unfiltered cigarettes (containing 1.0 mg nicotine and 14 mg tar in each cigarette) for 30 min, twice daily, 6 days/week for 4 weeks, the % AB/PAS-stained epithelium increased by ca. 12% (vs ca. 1% in air-exposed animals), Muc5ac mRNA expression increased more than 2-fold, and the % Muc5ac-stained epithelium increased from ca. 1.5% to approx. 6% relative to control (An et al., 2013).
In Sprague-Dawley rats that were whole-body exposed to 4% (v/v air) cigarette smoke for 1 h daily, for 56 days, the number of goblet cells in the bronchial epithelium significantly increased (ca. 10 cells/mm epithelium in air controls vs 60 cells/mm), and the number of Muc5ac-positive cells increased from ca. 20 cells/mm to ca. 80 cells/mm (Liang et al., 2017).
In Sprague-Dawley rats that were whole-body exposed to cigarette smoke from 5 unfiltered cigarettes for 30 min, twice daily for 4 weeks, the proportion of AB/PAS-positive airway epithelium increased from 7.7 ± 62.11% (air controls) to 42.04 ± 5.40%, Muc5ac mRNA expression levels Ninincreased by about 5-fold and Muc5ac protein expression levels increased approx. 8-fold over controls (Ning et al., 2013).
There was a prominent increase in the numbers of goblet cells along the airway surface epithelium of Balb/c mice that were whole body exposed to cigarette smoke from 5 cigarettes (1.1 mg nicotine and 11 mg tar per cigarette) for 30 min twice daily, 6 days per week, for 4 weeks. Consistent with the AB/PAS staining results, the percentage of bronchial epithelial surface area positively stained by anti-Muc5ac monoclonal antibody markedly increased after 24 days of exposure (Xu et al., 2015).
The large airways of mice that were whole body exposed to cigarette smoke of 10 cigarettes (160–180 mg/m3 TPM; TE-10, Teague Enterprises) for 2 h a day, 5 days a week, for up to 12 weeks, exhibited goblet cell hyperplasia and increased mucus production, evidenced by histology and increases in the numbers of PAS-positive goblet cells (approx. 15% compared to control) and Muc5ac-positive cells (approx. 50% compared to control)(Zhou et al., 2016).
Forty-eight h after intra-tracheal administration 300 mg/kg LPS (E. coli strain 0111:B4), Sprague-Dawley rat lungs exhibited goblet cell hyperplasia, evidenced by ca. 2-fold increases in the numbers of UEA-1 (wheat agglutinin)-, MUC5AC-, and PAS-positive goblet cells compared with PBS controls (Silva et al., 2012).
Male C57BL/6 mice—sensitized subcutaneously with 100 mg of Freund adjuvant–emulsified house dust mite (HDM; 1 mg/mL) in abdomen and groins on days 0 and 14 and challenged intranasally with 50 mg of HDM extract dissolved in PBS (1mg/mL), starting on day 21, daily for 14 d—developed goblet cell hyperplasia (histology), with significant increases in PAS-positive area (ca. 8-fold) and Muc5ac protein expression (ca. 30-fold) (Shi et al., 2017).
Ferrets that were exposed to smoke from 3R4F research cigarettes for 1 h, twice daily for 6 months (SCIREQ, InExpose model) developed goblet cell hyperplasia in medium and small airways, evidenced by histopathological examination of AB/PAS-stained lung tissues. Mucus expression measured by PAS-positive goblet cell area, normalized by the size of the airway lumen to account for cell variation due to airway diameter, was 60% (0.042% ± 0.025% smoke vs. 0.025% ± 0.013% air control; P = 0.06) higher in smoke-exposed airways than in control airways. Muc5b and Muc5ac staining was greater in smoke-exposed ferrets, but patchy staining made quantification impossible (Raju et al., 2016).
In primary human bronchial epithelial cells differentiated at the air-liquid interface, basolateral treatment with 10 ng/mL IL-13 increased the number of goblet cells from 0.2 ± 0.1 to 15.9 ± 1.1, the number of PAS-positive cells from 2.5 ± 1.5 to 28.2 ± 0.7, and the number of MUC5AC-positive cells from 0.1 ± 0.1 to 25.7 ± 1.0 (Tanabe et al., 2011). Similarly, treatment of 3D bronchial organotypic cultures with 5 ng/mL IL-13 for 14 days caused goblet cell hyperplasia (histology), significantly increasing MUC5AC protein concentration (ca. 1.5-fold) in the supernatant and MUC5AC mRNA expression (ca. 10-fold) compared with vehicle (DMSO) (Mishina et al., 2015).
IL-13, added to primary human bronchial epithelial cells at the first day of air-liquid interface culture, dose-dependently increased goblet cell density (AB staining, manual counting) and MUC5AC protein expression (antibody staining, semi-automated counting). Treatment with 1 ng/mL IL-13 resulted in the largest increase in goblet cell density, independent of the counting method, with one donor showing a 5.47 ± 0.92-fold increase and the other a 10.86 ± 1.25-fold increase. The highest concentration of IL-13 studied (10 ng/mL) significantly reduced the goblet cell density in both donors. Results with IL-4 treatment were similar to those with IL-13; maximal increase in goblet cell density was achieved with 1 ng/mL, and goblet cell density decreased at 10 ng/mL (Atherton et al., 2003).
Morphometric analysis of endobronchial biopsies from patients with mild and moderate asthma showed that stored mucin in goblet cells, expressed as the volume density of mucin in the airway epithelium, was three times higher in asthmatics than in healthy subjects. Although the goblet cell size was similar in both groups, the goblet cell number was significantly increased in the subjects with asthma (41,959 ± 9,230 in controls vs 93,043 ± 15,824), indicating that the increase in stored mucin in goblet cells was secondary to goblet cell hyperplasia. MUC5AC was the most frequently expressed mucin gene in both groups, and MUC5AC gene expression was increased in the subjects with asthma, but not significantly so (Ordonez et al., 2001).
In nasal polyp tissues from 8 patients with nasal polyposis, hyperplastic epithelium occupied a mean of 75% (range, 44%-100%). Approx. 55% of the polyp epithelium exhibited positive AB/PAS staining and positive MUC5AC staining, which were significantly higher proportions of goblet cell markers than seen in the pseudostratified epithelium from controls (Burgel et al., 2000). Similarly, goblet cell hyperplasia was seen in nasal polyp tissues from 25 patients but not healthy controls, as evidenced by more PAS-positive epithelial cells (PAS staining index 1.9 [1.3, 2.2] vs 0.7 [0.4, 1.2] in controls). This was accompanied by increased MUC5AC staining, with a mean staining score of 2.2 [1.7, 3.0] in polyp tissues vs 0.6 [0.4, 1.1] in normal controls, and increased MUC5AC gene expression, with levels of 4.4 2.3, 6.3] in polyp tissues vs 1.2 [0.4, 2.2] in normal controls (Xia et al., 2014).
AB/PAS staining of lung tissues revealed a higher number of goblet cells (goblet cell rate 0.20 ± 0.10% vs 0.13 ± 0.06%) as well as higher MUC5AC expression (0.27 ± 0.09% vs 0.20 ± 0.10%) in COPD patients than in healthy controls (Ma et al., 2005).
Healthy smokers (9.80±3.49 cells/mm) had a greater goblet cell density than nonsmokers (2.31±1.81 cells/mm). Healthy smokers (26.35±10.96 μL/mm2) also had a greater mucin volume density than nonsmokers (5.77±4.34 μL/mm2). There was a significant correlation between pack-year history of smoking with goblet cell density (Kim et al., 2015).
Time-scale
Brown–Norway rats were sensitized by an intraperitoneal injection with 1 mg ovalbumin (OVA) and 200 mg Al(OH)3 in 1mL of sterile saline on days 0 and 7. The rats were then exposed to aerosolized 1% (w/v) OVA or sterile saline for 30 min on days 14–16. Marked goblet cell hyperplasia (evidenced by AB/PAS staining) was observed in the epithelium throughout the airways of the OVA-sensitized and -challenged rats 24 h after the final OVA challenge (on day 17), and the goblet cell hyperplasia progressed further on day 24. The area of AB/PAS-positive staining of the airway epithelium on day 24 revealed a 7-fold increase in the OVA-sensitized and -challenged rats relative to the OVA-sensitized and saline-treated controls (Takeyama et al., 2008).
In rats exposed to 400 ppm SO2 for 3 h a day, 5 days a week, for up to 6 weeks, the number of goblet cells in the trachea and main bronchi initially decreased. After 3 weeks, goblet cell numbers and size increased from day 4 onward, and goblet cells started appearing also in distal airways (where they are normally not present). With continuing exposure (at 6 weeks), goblet cell numbers keep increasing in the trachea (ca. 1.5-fold), proximal (ca. 2-fold) and distal airways (ca. 30-fold) (Lamb and Reid, 1968).
Intratracheal instillation of agarose plugs (0.7- to 0.8-mm diameter; 4% agarose type II) in male Fischer 344 rats caused goblet cell hyperplasia, evidenced by histology and AB/PAS staining. In the airways containing the plugs, goblet cell numbers increased from 0 cells/mm basal lamina to 13.1±5.6, 25.7±15.0, and 51.5±9.0 cells/mm basal lamina after 24, 48, and 72 h, respectively. The percentage of the total length of epithelium staining positively with AB/PAS increased from 0.1 ± 0.1% in control animals to 4.7 ± 1.4, 13.3 ± 0.7, and to 19.1 ± 0.7% at 24, 48, and 72 h, respectively. Muc5ac gene expression was found preferentially in cells that were AB/PAS-positive and increased in a time-dependent manner (Lee et al., 2000).
Known Feedforward/Feedback loops influencing this KER
Unknown
Domain of Applicability
Goblet cell hyperplasia is a common feature in the airways of humans, mice, rats and guinea pigs following exposure to noxious agents such as cigarette smoke.
References
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