Glutamine plays a key role in intestinal growth and maintenance of gut function, and as we have shown protects the postischemic gut. However, the precise mechanisms of glutamine's gut protective effects have not been well elucidated. In present study, RNA microarray was performed to obtain differentially expressed genes in IEC-6 cells following either 2mM or 10mM glutamine. The result demonstrated that Sp3 mRNA expression was down-regulated 3.1 fold. PCR and Western blot confirmed that Sp3 protein was decreased by glutamine in a time and dose-dependent fashion. To investigate the role of Sp3, Sp3 gene siRNA silencing was performed and apoptosis was assessed. Silencing of Sp3 demonstrated a significant increase in Bcl-2 and decrease in Bax protein expression, as well as a decrease in caspase-3, 8, and 9 protein expression and activity. The protein expression of apoptosis-related proteins after hypoxia/ reoxygenation was similar to that of normoxia and correlated with a decrease in DNA fragmentation. Importantly, the addition of glutamine to Sp3 silenced cells did not further lessen apoptosis, suggesting that Sp3 plays a major role in glutamine's inhibitory effect on apoptosis. This novel finding may explain in part glutamines gut protective effects.
- DNA fragmentation
- Copyright © 2010, American Journal of Physiology- Gastrointestinal and Liver Physiology