Underexpression of Receptor for Activated C Kinase 1 (RACK1) in Leukocytes from Patients with Severe Acute...

Receptor for activated C kinase 1 (RACK1) plays an important role in regulating the immune response and cytokine expression. However, little is known about its role in acute pancreatitis (AP). We therefore investigated the role of RACK1 in AP and explored its relationship with interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), both of which are related to AP severity. Two rat models of chemically induced AP with different severities were used: acute edematous pancreatitis (AEP) and acute necrotizing pancreatitis (ANP). The expression levels of IL-6 and TNF-α mRNAs and proteins were significantly increased in leukocytes from AEP and ANP rats, compared with the levels in the control animals, while the expression levels of RACK1 mRNA and protein were significantly decreased in leukocytes from these AP rats. Moreover, the RACK1 levels in leukocytes were significantly lower in ANP rats than those in AEP rats. Consequently, AP patients and healthy volunteers (HVs) were enrolled in this study. Compared with the HVs (n = 5), the expression levels of IL-6 and TNF-α mRNAs and proteins were significantly higher in leukocytes from 15 AP patients, including patients with mild AP (n = 5). By contrast, the expression levels of RACK1 mRNA and protein in leukocytes were significantly lower among patients with severe AP (n = 5) and with moderately severe AP (n = 5), compared with the HVs. The expression levels of RACK1 mRNA were negatively correlated with the IL-6 and TNF-α mRNA levels. Thus, RACK1 may alleviate the severity of AP.