Differential mucin phenotypes and their significance in a variation of colorectal carcinoma

AIM: To investigate mucin expression profiles in colorectal carcinoma (CRC) histological subtypes with regard to clinicopathologic variables and prognosis.

METHODS: Mucin (MUC)2 and MUC5AC expressions were assessed by immunohistochemistry for a total of 250 CRC cases that underwent surgical resection. CRCs included 63 well-to-moderately differentiated adenocarcinomas (WMDAs), 91 poorly differentiated adenocarcinomas (PDAs), 81 mucinous adenocarcinoma (MUAs), and 15 signet-ring cell carcinomas (SRCCs). MUC2 and MUC5AC were scored as positive when ≥ 25% and ≥ 1% of cancer cells were stained positive, respectively. The human mutL homolog 1 and human mutS homolog 2 expressions were assessed by immunohistochemistry in PDAs to investigate mismatch-repair (MMR) status. Tumors that did not express either of these two were considered MMR-deficient. Results were analyzed for associations with clinicopathologic variables and the prognosis in individual histological CRC subtypes.

RESULTS: MUC2-positive and MUC5AC-positive WMDA percentages were 49.2% and 30.2%, respectively. In contrast, MUC2-positive and MUC5AC-positive PDA percentages were 9.5% and 51.6%, respectively. MUC2 levels tended to decrease and MUC5AC levels tended to increase from WMDA to PDA. In 21 tumors comprising both adenoma and adenocarcinoma components in a single tumor (4 WMDAs, 7 PDAs, and 10 MUAs), MUC2 was significantly downregulated in PDA and MUC5AC was downregulated in PDA and MUA in the adenoma-carcinoma sequence. These results suggested that MUC2 levels might be associated with malignant potential and that MUC5AC expression was an early event in tumorigenesis. Despite worse prognoses than WMDA, high MUC2 expression levels were maintained in MUA (95.1%) and SRCC (71.5%), which suggested a pathogenesis for these subtypes distinct from that of WMDA. No significant associations were found between MUC2 expression and any clinicopathologic variables in any histological subtype. MUC5AC expression in PDA was closely associated with right-sided location (P = 0.017), absence of nodal metastasis (P = 0.010), low tumor node metastasis stage (P = 0.010), and MMR deficiency (P = 0.003). MUC2 expression in WMDA was a marginal prognostic factor for recurrence/metastasis-free survival (RFS) by univariate Cox analysis (P = 0.077) but not by multivariate Cox analysis (P = 0.161). MUC5AC expression in PDA was a significant prognostic factor for RFS by univariate Cox analysis (P = 0.007) but not by multivariate Cox analysis (P = 0.104). Kaplan-Meier curves and log-rank tests revealed that MUC2 expression was marginally associated with a better WMDA prognosis [P = 0.064 for RFS and P = 0.172 for overall survival (OS)] but not for PDA. In contrast, MUC5AC expression was significantly and marginally associated with a better PDA prognosis in terms of RFS and OS, respectively (P = 0.004 for RFS and P = 0.100 for OS), but not for WMDA and MUA.

CONCLUSION: Mucin core protein expression profiles and clinical significance differ according to histological CRC subtypes. This may reflect different pathogeneses for these tumors.

Interleukin-13 stimulates MUC5AC expression via a STAT6-TMEM16A-ERK1/2 pathway in human airway epithelial cells

Transmembrane protein 16A (TMEM16A), a channel underlying the calcium-activated chloride channel (CaCC) currents, has been shown to be a key regulator of mucus overproduction in airway epithelial cells. However, the precise molecular mechanism involved in the TMEM16A-mediated mucus secretion remains unclear. In the present study, we inquired into a novel signaling mechanism for TMEM16A driving mucin 5AC (MUC5AC) production in human airway epithelial cells. Following treatment for 24-48h with type 13 interleukin (IL-13), an upregulation of TMEM16A expression in both mRNA and protein levels was observed in human bronchial epithelial cell line (HBE16), while signal transducer and activator of transcription 6 (STAT6) inhibition could decrease this elevated expression, suggesting that the regulation of TMEM16A expression by IL-13 was via a STAT6-based transcriptional mechanism. Further investigation of the HBE16 cells revealed that TMEM16A knockdown or specific chloride channel inhibitor T16Ainh-A01 could suppress the CaCC currents and consequently reduce the extracellular regulated kinase (ERK1/2) phosphorylation, accompanying a dramatical decrease in MUC5AC expression. Moreover, pretreated with PD98059, an inhibitor of ERK1/2, the HB16 cells showed a remarkable diminution in TMEM16A-mediated MUC5AC expression. Altogether, STAT6-TMEM16A-ERK1/2 signal pathway and TMEM16A channel activity are required for the IL-13-induced TMEM16A mediated mucus production.

Benzo(a)pyrene induces MUC5AC expression through the AhR/mitochondrial ROS/ERK pathway in airway epithelial cells

OBJECTIVES

Benzo(a)pyrene (BaP) is a ubiquitous air pollutants, and BaP exposure leads to a risk of respiratory diseases. The oversecretion of airway mucus and high expression of mucin 5AC (MUC5AC) are associated with common respiratory disorders caused by air pollution. We aimed to investigate the effect of BaP on MUC5AC expression, especially the mechanisms by which BaP induces MUC5AC gene expression.

METHODS

The human airway epithelial cell NCI-H292 was used to test the effects of BaP on the expression of MUC5AC in vitro. MUC5AC mRNA and protein expression were assessed with real-time quantitative PCR, immunochemistry, and western blotting. A luciferase assay was conducted to detect the activity of the promoter. The total cellular ROS and mitochondrial ROS were measured by corresponding probes. Small-interfering RNAs were used for gene silencing. AhR-overexpressing cell lines were constructed by transfection with AhR overexpression lentivirus.

RESULTS

We found that BaP stimulation upregulated the MUC5AC mRNA and protein levels and activated the ERK pathway. Suppressing ERK with U0126 (an ERK inhibitor) or knocking down ERK with siRNA decreased BaP-induced MUC5AC expression. The luciferase activity transfected with the MUC5AC promoter and cAMP-response element (CRE) was increased after BaP treatment, whereas CREB siRNA suppressed the BaP-induced overexpression of MUC5AC. In addition, BaP increased mitochondrial ROS production, and Mito-TEMP, a mitochondrial ROS inhibitor, inhibited BaP-induced MUC5AC expression and ERK activation. BaP increased the mRNA levels of CYP1A1 and CYP1B1, while Alizarin, a CYP1s inhibitor, suppressed the effects of BaP, including the MUC5AC overexpression, ERK activation and mitochondrial ROS generation. BaP induced the translocation of aryl hydrocarbon receptor (AhR) from the cytoplasm to the nucleus. SiRNA-mediated knockdown or chemical inhibition of AhR decreased the BaP-induced expression of MUC5AC, while the overexpression of AhR significantly enhanced the BaP-induced expression of MUC5AC. ITE, an endogenous AhR ligand, also upregulated the mRNA and protein expression of MUC5AC. Furthermore, resveratrol treatment inhibited the BaP-induced MUC5AC overexpression, AhR translocation, mitochondrial ROS production and ERK pathway activation.

CONCLUSION

Here, we highlighted the crucial role of AhR/mitochondrial ROS/ERK pathway activation in BaP-induced MUC5AC overexpression and identified resveratrol as a promising drug to reduce BaP-induced MUC5AC overexpression.

Gastric mucin expression in Helicobacter pylori-related, nonsteroidal anti-inflammatory drug-related and idiopathic ulcers

AIM: To determine the pattern of secreted mucin expression in Helicobacter pylori (H. pylori)-related, nonsteroidal anti-inflammatory drug (NSAID)-related and idiopathic gastric ulcers.

METHODS: We randomly selected 92 patients with H. pylori-associated (n = 30), NSAID-associated (n = 18), combined H. pylori and NSAID-associated gastric ulcers (n = 24), and patients with idiopathic gastric ulcers (n = 20). Immunohistochemistry for T-cell CD4/CD8, and for mucin 5AC (MUC5AC) and mucin 6 (MUC6), was performed on sections of the mucosa from the ulcer margin. Inflammation score was assessed according to the Sydney system.

RESULTS: MUC5AC was expressed on the surface epithelium (98.9%) and neck glands (98.9%) with minimal expression in the deep glands (6.5%). MUC6 was strongly expressed in the deep glands (97.8%), variable in the neck glands (19.6%) and absent in the surface epithelium (0%). The pattern of mucin expression in idiopathic ulcer margins was not different from the expression in ulcers associated with H. pylori, NSAIDs, or combined H. pylori and NSAIDs. CD4/CD8 ratio was higher in H. pylori-positive patients (P = 0.009). Idiopathic ulcers are associated with hospitalized patients and have higher bleeding and mortality rates.

CONCLUSION: Idiopathic ulcers have a unique clinical profile. Gastric mucin expression in idiopathic gastric ulcers is unchanged compared with H. pylori and/or NSAID-associated ulcers.

Pinellia ternata Attenuates Mucus Secretion and Airway Inflammation after Inhaled Corticosteroid Withdrawal in COPD Rats

Inhaled corticosteroids (ICS) are widely used to manage chronic obstructive pulmonary disease (COPD). However, withdrawal of ICS generally causes various adverse effects, warranting careful management of the ICS withdrawal. Pinellia ternata, a traditional Chinese herbal medicine, has been used to treat respiratory diseases in China for centuries. Here, we investigated its role in antagonizing ICS withdrawal-induced side effects, and explored the underlying mechanisms. The rat COPD model was established using a combination of passive cigarette smoking and intratracheal instillation of lipopolysaccharide (LPS). COPD rats were treated with saline or budesonide inhalation, or with budesonide inhalation followed by saline inhalation or Pinellia ternata gavage. The number of goblet cells and the level of mucin 5AC (MUC5AC) were enhanced by budesonide withdrawal. Pinellia ternata treatment significantly blocked these effects. Further, Pinellia ternata treatment reversed budesonide withdrawal-induced increase of interleukin 1[Formula: see text] (IL-1[Formula: see text] and tumor necrosis factor [Formula: see text] (TNF-[Formula: see text]) levels in bronchoalveolar lavage fluid (BALF). Extracellular signal-regulated kinase (ERK), but neither p38 nor c-Jun N-terminal kinase (JNK), was activated by budesonide withdrawal, and the activation was blocked by Pinellia ternata treatment. The MUC5AC expression was positively correlated with goblet cell number, IL-1[Formula: see text] and TNF-[Formula: see text] levels, and ERK activity. Pinellia ternata treatment protected the airway from ICS withdrawal-induced mucus hypersecretion and airway inflammation by inhibiting ERK activation. Pinellia ternata treatment may represent a novel therapeutic strategy to prevent ICS withdrawal-induced side effects in COPD patients.

Piscroside C inhibits TNF-α/NF-κB pathway by the suppression of PKCδ activity for TNF-RSC formation in human airway epithelial cells

BACKGROUND

Piscroside C, isolated from Pseudolysimachion rotundum var. subintegrum, is a novel iridoid glycoside with therapeutic efficacy in a mouse model of chronic obstructive pulmonary disease (COPD). Piscroside C has been reported as a constituent of YPL-001 (under Phase 2a study, ClinicalTrials.gov identifier NCT02272634).

PURPOSE

To investigate the mechanisms behind piscroside C therapeutic effects on COPD in human airway epithelial NCI-H292 cells.

METHODS

We tested if piscroside C effectively suppresses MUC5AC gene expression and TNF-RSC/IKK/NF-κB cascades in TNF-α-stimulated NCI-H292 cells by employing, reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, luciferase reporter assays, chromatin immunoprecipitation assays and immunoprecipitation.

RESULTS

Piscroside C markedly suppressed the expression of TNF-α-induced MUC5AC mucus protein by inhibiting the transcriptional activity of NF-κB in NCI-H292 cells. Indeed, piscroside C negatively regulated the function of TNF receptor 1 signaling complex (TNF-RSC, an upstream regulator of the NF-κB pathway) without affecting its extracellular interaction with the TNF-α ligand. This inhibitory effect by piscroside C is mediated by the inactivation of protein kinase C (PKC), an essential regulator of TNF-RSC. PKC inactivation by piscroside C results in decreased PKCδ binding to a TRAF2 subunit of TNF-RSC and subsequent reduced IKK phosphorylation, resulting in NF-κB inactivation.

CONCLUSION

We propose that piscroside C is a promising therapeutic constituent of YPL-001 through its inhibition of PKCδ activity in the TNF-RSC/IKK/NF-κB/MUC5AC signaling cascade.

Proteomic analysis of cancer and mesothelial cells reveals an increase in Mucin 5AC during ovarian cancer and peritoneal interaction

Ovarian cancer is a highly metastatic disease that is often characterized by widespread abdominal dissemination. A hallmark of ovarian cancer progression is the attachment of malignant cells to the mesothelium and the formation of invasive peritoneal implants. Therefore, delineating factors involved in cancer-peritoneal cell interaction is critical to improving patient survival, as it may lead to the discovery of novel therapeutic targets. As such, we aimed to identify proteins that participate in this interaction by comparing the secreted proteome of a co-culture model containing ovarian cancer (OVCAR-5) and mesothelial cells (LP-9), to their respective monoculture secretomes. In total, 49 proteins were differentially secreted during cancer and mesothelial cell contact. Relative mRNA expression of candidates was performed, which revealed a significant increase in MUC5AC gene expression in cancer cells cultured in three different co-culture models (OVCAR-5 and LP-9; BG-1 and LP-9; OV-90 and LP-9). An increased expression was also observed in LP-9 cells that were co-cultured with OVCAR-5 and OV-90 cancer cells. Further immunocytochemistry analysis also confirmed increased expression of MUC5AC in ovarian cancer and peritoneal co-cultures. Overall, our analysis uncovers novel molecular markers of peritoneal metastasis, which may have potential roles in regulating the progression of the disease.

BIOLOGICAL SIGNIFICANCE

In this study, our objective was to focus on identifying novel mediators of ovarian cancer and peritoneal interaction using a mass spectrometry-based approach. Our analysis resulted in the discovery of both previously known and novel factors involved this interaction, and as such, these newly discovered proteins might have potential roles in cancer progression, such as invasion and adhesion. We believe that these findings add to our current knowledge and understanding of ovarian cancer progression, and will aid researchers in their future attempts in finding new targets of the disease.

Somatic molecular changes and histo-pathological features of colorectal cancer in Tunisia

AIM: To determine correlations between family history, clinical features and mutational status of genes involved in the progression of colorectal cancer (CRC).

METHODS: Histo-pathological features and molecular changes [KRAS, BRAF and CTNNB1 genes mutations, microsatellite instability (MSI) phenotype, expression of mismatch repair (MMR) and mucin (MUC) 5AC proteins, mutation and expression analysis of TP53, MLH1 promoter hypermethylation analysis] were examined in a series of 51 unselected Tunisian CRC patients, 10 of them had a proven or probable hereditary disease, on the track of new tumoral markers for CRC susceptibility in Tunisian patients.

RESULTS: As expected, MSI and MMR expression loss were associated to the presence of familial CRC (75% vs 9%, P < 0.001). However, no significant associations have been detected between personal or familial cancer history and KRAS (codons 12 and 13) or TP53 (exons 4-9) alterations. A significant inverse relationship has been observed between the presence of MSI and TP53 accumulation (10.0% vs 48.8%, P = 0.0335) in CRC tumors, suggesting different molecular pathways to CRC that in turn may reflect different environmental exposures. Interestingly, MUC5AC expression was significantly associated to the presence of MSI (46.7% vs 8.3%, P = 0.0039), MMR expression loss (46.7% vs 8.3%, P = 0.0039) and the presence of familial CRC (63% vs 23%, P = 0.039).

CONCLUSION: These findings suggest that MUC5AC expression analysis may be useful in the screening of Tunisian patients with high risk of CRC.

PM2.5 Upregulates the Expression of MUC5AC via the EGFR-PI3K Pathway in Human Sinonasal Epithelial Cells

BACKGROUND

Fine particulate matter (PM) (PM with an aerodynamic diameter <2.5 μm, PM2.5) exposure contributes to respiratory disease development and exacerbation.

OBJECTIVE

We sought to investigate the effect of PM2.5 exposure on mucociliary function in primary human nasal epithelial cells (HNECs) and the underlying mechanism.

METHODS

HNECs derived from control subjects and patients with chronic rhinosinusitis with nasal polyps were established as air-liquid interface cultures. Confluent cultures were exposed to 100 or 200 μg/mL PM2.5 for 24 h and assessed for expression of specific mucociliary-associated factors, the percentage of β-tubulin IV-positive and MUC5AC-positive cells, expression of epidermal growth factor receptor (EGFR) ligand and activation of phosphoinositide 3-kinase (PI3K)-AKT/ERK. In addition, cultures pretreated for 30 min with AG1478 (an EGFR inhibitor) or LY294002 (a PI3K inhibitor) following PM2.5 exposure were assessed for MUC5AC mRNA and protein expression.

RESULTS

PM2.5 exposure at 100 or 200 μg/mL for 24 h did not affect geminin coiled-coil domain containing, multiciliate differentiation and DNA synthesis associated cell cycle protein, FOXJ1, or DNAI2 mRNA expression or the percentage of β-tubulin IV-positive cells. However, 200 μg/mL PM2.5 exposure significantly increased mRNA expression of SAM-pointed domain-containing ETS transcription factor and MUC5AC and the percentage of MUC5AC-positive cells. PM2.5 also increased expression of EGFR ligands, including heparin-binding EGF-like growth factor and amphiregulin. Furthermore, PM2.5induced activation of PI3K, AKT, and ERK, and pretreatment of HNECs with AG1478 or LY294002 attenuated PM2.5-induced MUC5AC mRNA and protein expression.

CONCLUSIONS AND CLINICAL RELEVANCE

This study demonstrates that short-term PM2.5 exposure increases MUC5AC expression in HNECs. Furthermore, this study shows that PM2.5-induced MUC5AC expression is likely mediated through the EGFR-PI3K pathway.

Curcumin Inhibits Lipopolysaccharide-Induced Mucin 5AC Hypersecretion and Airway Inflammation via Nuclear Factor Erythroid 2-Related Factor 2

Background:

Excess mucus production is an important pathophysiological feature of chronic inflammatory airway diseases. Effective therapies are currently lacking. The aim of the study was to evaluate the effects of curcumin (CUR) on lipopolysaccharide (LPS)-induced mucus secretion and inflammation, and explored the underlying mechanism in vivo and in vitro.

Methods:

For the in vitro study, human bronchial epithelial (NCI-H292) cells were pretreated with CUR or vehicle for 30 min, and then exposed to LPS for 24 h. Next, nuclear factor erythroid 2-related factor 2 (Nrf2) was knocked down with Nrf2 small interfering RNA (siRNA) to confirm the specific role of Nrf2 in mucin regulation of CUR in NCI-H292 cells. In vivo, C57BL/6 mice were randomly assigned to three groups (n = 7 for each group): control group, LPS group, and LPS + CUR group. Mice in LPS and LPS + CUR group were injected with saline or CUR (50 mg/kg) intraperitoneally 2 h before intratracheal instillation with LPS (100 μg/ml) for 7 days. Cell lysate and lung tissue were obtained to measured Mucin 5AC (MUC5AC) and Nrf2 mRNA and protein expression by a real-time polymerase chain reaction and Western blotting. Bronchoalveolar lavage fluid (BALF) was collected to enumerate total cells and neutrophils. Histopathological changes of the lung were observed. Data were analyzed by one-way analysis of variance. Student's t-test was used when two groups were compared.

Results:

CUR significantly decreased the expression of MUC5AC mRNA and protein in NCI-H292 cells exposed to LPS. This effect was dose dependent (2.424 ± 0.318 vs. 7.169 ± 1.785, t = 4.534, and 1.060 ± 0.197 vs. 2.340 ± 0.209, t = 7.716; both P < 0.05, respectively) and accompanied by increased mRNA and protein expression of Nrf2 (1.952 ± 0.340 vs. 1.142 ± 0.176, t = −3.661, and 2.010 ± 0.209 vs. 1.089 ± 0.132, t = −6.453; both P < 0.05, respectively). Furthermore, knockdown of Nrf2 with siRNA increased MUC5AC mRNA expression by 47.7%, compared with levels observed in the siRNA-negative group (6.845 ± 1.478 vs. 3.391 ± 0.517, t = −3.821, P < 0.05). Knockdown of Nrf2 with siRNA also markedly increased MUC5AC protein expression in NCI-H292 cells. CUR also significantly decreased LPS-induced mRNA and protein expression of MUC5AC in mouse lung (1.672 ± 0.721 vs. 5.961 ± 2.452, t = 2.906, and 0.480 ± 0.191 vs. 2.290 ± 0.834, t = 3.665, respectively; both P < 0.05). Alcian blue/periodic acid-Schiff staining also showed that CUR suppressed mucin production. Compared with the LPS group, the numbers of inflammatory cells (247 ± 30 vs. 334 ± 24, t = 3.901, P < 0.05) and neutrophils (185 ± 22 vs. 246 ± 20, t = 3.566, P < 0.05) in BALF decreased in the LPS + CUR group, as well as reduced inflammatory cell infiltration in lung tissue.

Conclusion:

CUR inhibits LPS-induced airway mucus hypersecretion and inflammation through activation of Nrf2 possibly.

The applicability of ELISA detection of gastric mucosa-expressing proteins for the identification of vomit

The identification of vomit stains may be helpful for crime scene reconstruction. However, there is no specific and convenient method for identifying vomit stain. Therefore, to establish the procedure for forensic identification of vomit stains, we focused on four gastric mucosa-expressing proteins, pepsinogen I (PGA), pepsinogen II (PGC), gastrin (GAST), and mucin 5AC (MUC5AC). We developed enzyme-linked immunosorbent assay (ELISA) procedures for the detection of these four candidate proteins. The specificity and sensitivity of ELISA detection of these proteins were analyzed, and applicability for the identification of vomit in forensic casework samples was also investigated. We found the sensitivities of ELISA for detection of PGA, PGC, GAST, and MUC5AC from the standard protein (peptide) and from diluted gastric mucosa extract were 10.0-100.0 ng/ml and 1:200-1:1600, respectively. PGA and PGC were successfully detected in stomach contents and gastric mucosa samples; however, these also cross-reacted with some urine and semen samples, respectively, because of low level expression in these fluids. MUC5AC was positive for most gastric mucosa samples; however, it was difficult to detect in stomach contents. ELISA detection of GAST was not suitable for the identification of vomit. All aged samples stored up to 90 days gave positive results for ELISA procedures for PGA, PGC, and MUC5AC. Therefore, ELISA detection of these proteins might be applicable to aged samples. PGA was also detected in all actual vomit samples tested. These results suggest that ELISA for the detection of gastric mucosa-expressing proteins, especially PGA, could be an effective tool for the forensic identification of vomit.

Gene expression profiles of pro-inflammatory mediators in the conjunctiva of patients with epiblepharon

PURPOSE

To investigate the gene expression of pro-inflammatory mediators in the conjunctiva of pediatric patients with epiblepharon in a case-control study.

METHODS

Twenty healthy controls and 15 pediatric patients with epiblepharon were enrolled from April 23, 2020 to June 15, 2020. Epiblepharon severity was divided into class I-III (least to moderate severity) and class IV (most severe). We obtained impression cytologic specimens from the medial palpebral conjunctiva of the participants to measure the gene expression of interleukin (IL)-1β, IL-6, matrix metalloproteinase 9 (MMP9), and mucin 5AC (MUC5AC) using quantitative reverse transcription polymerase chain reaction.

RESULTS

The mean age in the epiblepharon group was 9 years (range 7.5-11 years), and that in the healthy control group was 9.5 years (range 8-11.3 years). IL-1β, IL-6, and MMP9 expression levels were 2.08 (p < 0.05), 2.11 (p < 0.05), and 2.48 (p < 0.05) fold higher, respectively, in the epiblepharon group than in the healthy control group. However, MUC5AC gene expression was not different between healthy subjects and patients with epiblepharon. IL-1β, IL-6, and MMP9 expression levels in class IV patients were 1.32 (p < 0.05), 1.77 (p < 0.05), and 1.98 (p < 0.05) fold higher, respectively, than in class I-III patients.

CONCLUSION

Epiblepharon may induce chronic inflammatory changes in the conjunctiva in addition to corneal epithelial damage. Therefore, early corrective surgery should be considered to prevent conjunctival inflammation.

Mechanobiology of conjunctival epithelial cells exposed to wall shear stresses

The human conjunctival epithelial cells (HCEC) line the inner sides of the eyelids and the anterior part of the sclera. They include goblet cells that secret mucus into the tear film that protects the ocular surface. The conjunctival epithelium is subjected to mechano-physical stimuli due to eyelid movement during blinking, during wiping and rubbing the eyes, and when exposed to wind and air currents. We cultured primary HCEC under air-liquid interface (ALI) conditions in custom-designed wells that can be disassembled for installation of the in vitro model in a flow chamber. We exposed the HCEC after ALI culture of 8-10 days to steady and oscillatory airflows. The in vitro model of HCEC was exposed to steady wall shear stresses (sWSS) of 0.5 and 1.0 dyne/cm² for lengths of 30 and 60 min and to oscillatory wall shear stresses (oWSS) of 0.5 and 0.77 dyne/cm² amplitudes for a length of 10 min. Cytoskeletal alterations and MUC5AC mucin secretion in response to WSS were investigated using immunohistochemically fluorescent staining and enzyme-linked lectin assay (ELLA), respectively. The results revealed that both exposure times and sWSS values increased the polymerization of F-actin filaments while mucin secretion decreased. However, after a recovery of 24 h in the incubator we observed a decrease of F-actin fibers and mucin secretion only for exposure of 30 min. The length of exposure was more influential on cytoskeletal alterations than the level of sWSS. The very small effect of sWSS on mucin secretion is most likely related to the much smaller amount of goblet cell than in other mucus-secreting tissue. The results for both oWSS amplitudes revealed similar trends regarding F-actin and mucin secretion. Immediately post-exposure we observed an increase in polymerization of F-actin filaments while mucin secretion decreased. However, after 24-h recovery we observed that both F-actin and mucin secretion returned to the same values as for unexposed cultures. The results of this study suggest that WSS should be considered while exploring the physiological characteristics of HCEC.

Understanding the Clinical Significance of MUC5AC in Biliary Tract Cancers

Biliary tract cancers (BTC) arise from biliary epithelium and include cholangiocarcinomas or CCA (including intrahepatic (ICC) and extrahepatic (ECC)) and gallbladder cancers (GBC). They often have poor outcomes owing to limited treatment options, advanced presentations, frequent recurrence, and poor response to available systemic therapy. Mucin 5AC (MUC5AC) is rarely expressed in normal biliary epithelium, but can be upregulated in tissues of benign biliary disease, premalignant conditions (e.g., biliary intraepithelial neoplasia), and BTCs. This mucin's numerous glycoforms can be divided into less-glycosylated immature and heavily-glycosylated mature forms. Reported MUC5AC tissue expression in BTC varies widely, with some associations based on cancer location (e.g., perihilar vs. peripheral ICC). Study methods were variable regarding cancer subtypes, expression positivity thresholds, and MUC5AC glycoforms. MUC5AC can be detected in serum of BTC patients at high concentrations. The hesitancy in developing MUC5AC into a clinically useful biomarker in BTC management is due to variable evidence on the diagnostic and prognostic value. Concrete conclusions on tissue MUC5AC are difficult, but serum detection might be relevant for diagnosis and is associated with poor prognosis. Future studies are needed to further the understanding of the potential clinical value of MUC5AC in BTC, especially regarding predictive and therapeutic value.

Gardenia jasminoides fruit extract alleviates non-steroidal anti-inflammatory drug-induced gastropathy in rats

BACKGROUND

NSAID-induced gastropathy is a health burden that requires effective intervention. Among various prevention options, Gardenia jasminoides fruit extract (GJE) has demonstrated gastroprotective effects through anti-inflammatory pathways with a wide safety margin. However, the detailed molecular mechanisms of GJE regarding mucoprotective and anti-inflammatory effects remained to be explored. Therefore, we investigated the effects of GJE on NSAID-induced gastric injury in rats, focusing on the expression of the protective factors: prostaglandin E2 (PGE2) and mucin 5AC (MUC5AC), and the aggravating factors: inducible nitric oxide synthase (iNOS) and nuclear factor-κB (NF-κB).

METHODS

Twenty-four male Sprague-Dawley rats were assigned to three experimental groups (n = 8/group): the control group, the NSAIDs group receiving indomethacin to induce gastric ulcers, and the NSAIDs with GJE pretreatment (NSAIDs + GJE) group. After a two-day experimental period, the stomachs were collected for histopathological examination, immunohistochemical staining, and protein expression analysis in gastric tissue lysates.

RESULTS

The NSAIDs group exhibited severe neutrophil infiltration with ulcers upon gastric histopathological examination. Pretreatment with GJE attenuated NSAID-induced gastropathy, as evidenced by reduced neutrophil infiltration and decreased ulceration. Immunohistochemical staining and Western blotting demonstrated reduced expressions of PGE2 and MUC5AC, while the expressions of iNOS and NF-κB were increased following NSAID administration. In comparison to the NSAIDs group, the NSAIDs + GJE group exhibited higher expressions of PGE2 and MUC5AC and lower expressions of iNOS and NF-κB, providing evidence of the gastroprotective effects of GJE.

CONCLUSIONS

Pretreatment with GJE alleviated NSAID-induced gastric ulcers by increasing the expression of PGE2 and MUC5AC and decreasing the expression of iNOS and NF-κB. This study contributes to the understanding of the mechanisms by which GJE attenuates NSAID-induced gastropathy. Further studies are required to validate the effect of GJE in clinical settings.