Murine gastric organoid culture.
To observe the changes of protein markers in the growth process of gastric organoids, we fixed the murine gastric organoids on day 1, 3, 5 and 7 respectively, and H+, K+ - ATPase, ezrin, F-actin and DAPI of parietal cells were stained, and photos were taken with confocal microscope (Fig. 1). Ezrin protein, a marker of the parietal membrane, indicated that the parietal membrane of murine gastric organoids was oriented towards the lumen and had polar distribution. The presence of H+, K+ - ATPase, a marker of parietal cells, suggested that the model system could be used to study the physiological and pathological characteristics of parietal cells.
In order to further semi quantitatively observe the changes of protein markers in the growth process of stomach organoids, murine gastric organoids were established, and collected on the 1st, 3rd, 5th, 7th, 9th and 11th day respectively, and the distribution of H+, K+ - ATPase, ezrin and F-actin markers in the parietal cell were detected. The results showed that the protein markers of murine gastric organoids remained stable in Day 5-9 (Fig. 1, d).
Ethanol impaired gastric organoids.
In order to observe the effect of different concentrations of ethanol on gastric organoids, final concentrations of 0%, 2%, 4%, 6%, and 8% EtOH were added to the culture medium to impair murine gastric organoids. One hour later, we stained them with 0.4% trypan blue solution and took photos under inverted fluorescence microscope (Olympus X81). Statistical analysis of organoids with positive trypan blue staining was carried out. As shown in Figure 2, the final concentration of EtOH was 6%. Trypan blue staining was found in 50% of the gastric organoids one hour after injury. However, when the concentration of EtOH exceeded 10%, the Matrigel was easy to dissolve and collapse, which affected the next observation and experiment.
In order to dynamically observe the impairment of 6% ethanol on the gastric organoids, the living gastric organoids were stained with Hoechst for 30 minutes, and then were placed under the microscope. Ethanol with the final concentration of 6% was added and the images were taken at the same time. The imaging time was 30 minutes. 30 minutes later, the nuclei of murine gastric organoids shrank and the lumen became narrower (Fig. 2, b).
Considering that the center of the gastric tube was a cystic luminal structure, and due to the concentration limitation of ethanol added to the medium, microinjection was used to inject the ethanol into the lumen of the gastric organoids (Fig. 2, c). One hour later. The samples were subjected to western blotting or immunofluorescence staining to observe impairment on gastric organoids. However, one hour after 6% ethanol was injected into the gastric organoids, no obvious impairment was observed. Next, we increased the concentration of ethanol to 50%. After 1 hour, we observed the death of organoids. As shown in Fig. 2, c, the gastric organoids were cultured, and microinjections of ethanol at different concentrations were performed on Day 6 of the organoids. One hour after microinjection of 50% ethanol into the organoids, the apical membrane marker ezrin and the parietal cell marker H+, K+-ATPase were destroyed, and the lumens of the organoids collapsed.
Next, the murine gastric organoids were impaired with EtOH added to the medium at a final concentration of 6%, and western blotting was performed at 0,15,30,45, and 60 minutes. It was found that there was a cleaved ezrin in 55kDa and the band had a tendency of becoming more and more obvious over time (Fig.2, d).
Immunofluorescence staining of ezrin, F-actin and DAPI (Fig. 3, a), or H+-K +-ATPase, ezrin and DAPI (Fig. 3, b) was performed 1 hour after gastric organoids were impaired by 6% ethanol added to the medium with a time gradient of 0-90 min. As can be seen from Fig. 3, a, with the prolongation of time, the location of the parietal membrane of ezrin gradually became diffuse, and the lumen of organoids shrunk.
Ethanol-induced organoids impairment was caused by calcium-dependent calpain activation.
To investigate whether the impairment of ethanol-mediated gastric organoids was caused by calcium-dependent calpain activation, gastric organoids were divided into four groups: 1.8 mM CaCl2 group, 1.8 mM CaCl2+ 6% ethanol group, 1.8mM CaCl2+6% ethanol + 100μM E64 group and 30μM BAPTA+1.8mM CaCl2+6% ethanol group. The murine gastric organoids were injured for 1 hour, and then samples were taken to run western blot to detect calpain I, ezrin and F-actin. Image J was used to measure the gray value of the strips. As a result, the hydrolyzed band of ezrin in the 1.8 mM CaCl2 + 6% ethanol group increased, and the difference was statistically significant(p<0.001) (Fig. 3, d).
To investigate whether alcohol-mediated gastric organoid damage is caused by calcium ions, we divided murine gastric organoids into four groups: 1.8 mM CaCl2 group, 1.8 mM CaCl2+6% EtOH group, 1.8 mM CaCl2+6. % EtOH + 2 mM EGTA group and 30 μM BAPTA + 1.8 mM CaCl2 + 6% EtOH group. Murine gastric organoids were impaired for 1 hour, and then samples were taken for western blot analysis of H+, K+-ATPase, Ezrin and F-actin. Image J was used to measure the gray value of the strips. Compared with the 1.8 mM CaCl2+6% EtOH group, the hydrolysis bands of Ezrin in BAPTA+1.8 mM CaCl2+6% ethanol group and 1.8 mM CaCl2+6% EtOH +2 mM EGTA group were significantly decreased, and the difference was statistically significant(p<0.001) (Fig. 3, d).
Effects of ethanol-mediated calcium ion impairment on the localization of ezrin, H+, K+-ATPase and F-actin in murine gastric organoids.
To investigate the effects of ethanol-mediated calcium impairment on the localization of ezrin and F-actin in murine gastric organoids, we divided murine gastric organoids into five groups: 1.8 mM CaCl2 group,1.8 mM CaCl2+6. % EtOH group, 1.8 mM CaCl2+ 6% EtOH + 2 mM EGTA group, 30 μM BAPTA + 1.8 mM CaCl2+ 6% EtOH group and 1.8 mM CaCl2+ 6% EtOH + 100 μM E64 group. The murine gastric organoids were impaired for 1 hour, followed by sample fixations, and the expressions of H+, K+-ATPase, ezrin and F-actin were detected by in situ immunofluorescence, and photographed by confocal microscopy LSM880.
Over time, the localization of ezrin in the apical membrane of organoids in the 1.8mM Ca2++6% EtOH group became blurred and diffused, while the localization of ezrin in the groups of 1.8mM Ca2++6% EtOH + EGTA group, 1.8mM Ca2+ +6% EtOH + BAPTA group and the 1.8 mM Ca2++ 6% EtOH + E64d group remained mostly in the apical membrane and was clear (Fig. 4).
To investigate the effects of ethanol-mediated calcium damage on the localization of ezrin and H+, K+-ATPase in murine gastric organoids, murine gastric organoids were divided into five groups: 1.8 mM CaCl2 goup,1.8 mM CaCl2. +6% EtOH group, 1.8 mM CaCl2+ 6% EtOH + 2 mM EGTA group, 30 μM BAPTA + 1.8 mM CaCl2 + 6% EtOH group and 1.8 mM CaCl2+ 6% EtOH + 100 μM E64 group. One hour later, the impaired murine gastric organoids were fixed and the expressions of H+, K+-ATPase and ezrin were detected by in situ immunofluorescence and photographed by confocal microscopy LSM880.
Over time, the localization of ezrin in the apical membrane of 1.8mM Ca2++6% EtOH group became blurred and diffused, while the localization of ezrin remained clear in the 1.8mM Ca2++6% EtOH + EGTA group, 1.8mM Ca2+ +6% EtOH + BAPTA group and the 1.8 mM Ca2++ 6% EtOH + E64d group, and the localization of H+, K+-ATPase did not change significantly (Fig. 4,b).
To investigate the effect of ethanol-mediated calcium ion on ezrin expression in human gastric organoids, we injured human gastric organoids either with 1.8 mM CaCl2, 1.8 mM CaCl2+6% EtOH, or with 1.8 mM CaCl2+6% EtOH + E64, respectively. After 1 hour, samples were collected for western blot, and the expressions of ezrin and actin were detected, and the values of the bands were measured with Image J (Fig. 5).
As can be seen from Fig. 5, ezrin in the 1.8 mM CaCl 2 + 6% EtOH group showed significant hydrolysis, suggesting an increase in the activity of calpain I. In the E64d group, no significant hydrolysis of ezrin was observed. There was no significant increase in calpain I activity, and the difference was statistically significant in the E64 group compared with the alcohol group (p < 0.05).