Role of the proteasome in rat indomethacin-induced gastropathy Stephen J. Brand, Zenichi Morise, Sven Tagerud, Laureen Mazzola, D.Neil Granger, Matthew B. Grisham  Gastroenterology  Volume 116, Issue 4, Pages 865-873 (April 1999) DOI: 10.1016/S0016-5085(99)70069-7 Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 1 Structure and Ki for inhibition of 20S proteasome by different proteasome inhibitors: MG 341, MG 224, and clasto-lactacystin lactone. Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 2 (A) Inhibition of NSAID gastropathy by oral gavage (□) or intravenous injection (○) of different doses of MG 341 dissolved 2 hours before oral dosing with indomethacin. Intravenous MG 341 was administered in 10% PEG 200 in 0.15 mol/L saline via tail vein. Oral administration was gavage with MG 341 suspended in methylcellulose. (B) Stereospecificity of proteasome inhibitor attenuation of indomethacin-induced gastric erosion. MG 341 (0.3 mg/kg) and the inactive D-enantiomer MG 398 (0.3 mg/kg) were administered by intravenous injection in 10% PEG 200 in 0.15 mol/L saline 2 hours before oral dosing with indomethacin. Results are expressed as mean erosion scores ± SE; n = 6 for each group. *P < 0.05 Kruskal–Wallis with Dunn's posttest comparison with vehicle. Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 2 (A) Inhibition of NSAID gastropathy by oral gavage (□) or intravenous injection (○) of different doses of MG 341 dissolved 2 hours before oral dosing with indomethacin. Intravenous MG 341 was administered in 10% PEG 200 in 0.15 mol/L saline via tail vein. Oral administration was gavage with MG 341 suspended in methylcellulose. (B) Stereospecificity of proteasome inhibitor attenuation of indomethacin-induced gastric erosion. MG 341 (0.3 mg/kg) and the inactive D-enantiomer MG 398 (0.3 mg/kg) were administered by intravenous injection in 10% PEG 200 in 0.15 mol/L saline 2 hours before oral dosing with indomethacin. Results are expressed as mean erosion scores ± SE; n = 6 for each group. *P < 0.05 Kruskal–Wallis with Dunn's posttest comparison with vehicle. Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 3 Duration of protection by MG 341 from indomethacin-induced gastric erosions. MG 341 was administered intravenously in tail 0, 2, 4, 6, and 12 hours before oral gavage with indomethacin. Results are expressed as erosion protection percentage as follows: Erosion Protection % = (US veh av − US Rx) × 100/US veh av, where US veh av is average erosion score of vehicle treatment and US Rx is erosion score after MG341. Results are expressed as mean erosion scores ± SE; n = 6 for each group. Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 4 (A) Correlation between the potencies of different boronate proteasome inhibitors in preventing indomethacin-induced gastric erosions and the IC50 of proteasome-dependent intracellular proteolysis of long-lived protein C2–C12 cells in culture (r = 0.7863, P < 0.0003; Spearman rank correlation). (B) Correlation between the potencies of different boronate proteasome inhibitors in attenuating indomethacin-induced gastric erosions and the minimum effective anti-inflammatory dose that inhibits ear swelling elicited by a delayed-type hypersensitivity (DTH) response. Correlations were calculated using the Spearman statistic with significance at level P > 0.05 (r = 0.6236; P < 0.0065). Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 4 (A) Correlation between the potencies of different boronate proteasome inhibitors in preventing indomethacin-induced gastric erosions and the IC50 of proteasome-dependent intracellular proteolysis of long-lived protein C2–C12 cells in culture (r = 0.7863, P < 0.0003; Spearman rank correlation). (B) Correlation between the potencies of different boronate proteasome inhibitors in attenuating indomethacin-induced gastric erosions and the minimum effective anti-inflammatory dose that inhibits ear swelling elicited by a delayed-type hypersensitivity (DTH) response. Correlations were calculated using the Spearman statistic with significance at level P > 0.05 (r = 0.6236; P < 0.0065). Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 5 Other classes of proteasome inhibitors protect against NSAID-induced gastric erosions. (A) The tripeptide aldehyde inhibitors morph-Leu-Leu-Leu-H (MG 224) (Ki, 20 nmol/L) and (B) the irreversible proteasome inhibitor clasto-lactacystin lactone were administered intravenously 2 hours before indomethacin was dosed by oral gavage. Vehicle was 25% DMSO plus 75% PEG 400. Results are expressed as mean erosion scores ± SE; n = 6 for each group. *P < 0.05, Kruskal–Wallis with Dunn's posttest comparison with vehicle. Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 5 Other classes of proteasome inhibitors protect against NSAID-induced gastric erosions. (A) The tripeptide aldehyde inhibitors morph-Leu-Leu-Leu-H (MG 224) (Ki, 20 nmol/L) and (B) the irreversible proteasome inhibitor clasto-lactacystin lactone were administered intravenously 2 hours before indomethacin was dosed by oral gavage. Vehicle was 25% DMSO plus 75% PEG 400. Results are expressed as mean erosion scores ± SE; n = 6 for each group. *P < 0.05, Kruskal–Wallis with Dunn's posttest comparison with vehicle. Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 6 Effect of the proteasome inhibitor MG 341 and its inactive D-stereoenantiomer MG 398 on the increased permeability of the gastric mucosal epithelial barrier caused by indomethacin. The effect of the structurally and mechanistically different proteasome inhibitor clasto-lactacystin lactone on gastric mucosal permeability was also studied. Mucosal permeability was measured by the increase in 65Cr-labeled EDTA clearance into the gastric lumen after intravenous injection. MG 341 and 398 (0.3 mg/kg) were administered by intravenous injection in 10% PEG 200 in 0.15 mol/L saline 2 hours before oral dosing with indomethacin. Results are expressed as mean ± SE; n = 4 for each group. *P < 0.05, Kruskal–Wallis with Dunn's posttest comparison with vehicle. Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 7 Effect of the proteasome inhibitor MG 341 and its inactive D-stereoenantiomer MG 398 on indomethacin-induced increase in gastric mucosal ICAM expression. The effect of the structurally and mechanistically different proteasome inhibitor clasto-lactacystin lactone on NSAID-enhanced gastric ICAM expression was also studied. Mucosal ICAM expression was measured as the binding of 125I-labeled MAb to rat ICAM. MG 341 and 398 (0.3 mg/kg) were administered by intravenous injection 2 hours before oral dosing with indomethacin. Results are expressed as mean ± SE; n = 4 for each group. *P < 0.05, Kruskal–Wallis with Dunn's posttest comparison with vehicle. Gastroenterology 1999 116, 865-873DOI: (10.1016/S0016-5085(99)70069-7) Copyright © 1999 American Gastroenterological Association Terms and Conditions