Activation of the Akt–CREB signalling axis by a proline-rich heptapeptide confers resistance to stress-induced cell death and inflammation

Cell stress of various kinds can lead to the induction of cell death and a damaging inflammatory response. Hence, a goal of therapeutic cell-stress management is to develop agents that might effectively regulate undesirable cell death and inflammation. To that end, we developed a synthetic peptide of seven amino acids based on structural mimicry to a functional domain of p53, a key factor in the responses of cells to stressful stimuli. This heptapeptide, which we term Stressin-1, was found to inhibit both cell death and the secretion of inflammatory mediators by various cell types in response to different stressful agents in vitro. The combined anti-inflammatory and anti-apoptotic activities of Stressin-1 were associated with a cellular signalling cascade that induced activation of Akt kinase and activation of the cAMP response element-binding protein (CREB) transcription factor. These immediate signalling events led to the inhibition of the signal transducer and activator of transcription and nuclear factor-κB pathways 24 hr later. Unexpectedly, we found no evidence for a direct involvement of p53 in the effects produced by Stressin-1. Intraperitoneal administration of 100 μg of Stressin-1 to lethally irradiated mice significantly protected them from death. These findings show that activating the Akt–CREB axis with Stressin-1 can counteract some of the undesirable effects of various cell stresses. Stressin-1 may have clinical usefulness.