Purification of a bioactive recombinant human Reg IV expressed in Escherichia coli

Recombinant human regenerating gene 4 attenuates the severity of osteoarthritis by promoting the proliferation of articular chondrocyte in an animal model

INTRODUCTION

Osteoarthritis (OA) is a dominant cause of morbidity and disability. As a chronic disease, its etiological risk factors and most therapies at present, are empirical and symptomatic. Regenerating gene 4 (Reg4) is involved in cell growth, survival, regeneration, adhesion, and resistance to apoptosis, which are partially thought to be the pathogenic mechanisms of OA. However, the proper role of Reg4 in OA is still unknown.

METHODS

In this study, a consecutive administration of rhReg4 was applied to normal Sprague-Dawley rats or rats after OA induction. Histological changes and chondrocyte proliferation in the articular cartilage were measured.

RESULTS

We found that RhReg4 promotes chondrocyte proliferation in normal rats, and RhReg4 attenuated the severity of OA in rats by promoting chondrocytes' proliferation in OA rats.

CONCLUSION

In conclusion, recombinant human regenerating gene 4 (rhReg4) attenuates the severity of osteoarthritis in OA animal models and may be used as a new method for the treatment of osteoarthritis.

Recombinant Reg3α protein protects against experimental acute pancreatitis in mice

Regenerating gene 3α (Reg3α) protein is a trophic factor that stimulates cell and tissue proliferation, neogenesis and also acts against apoptosis and necrosis. In order to explore the potential roles of recombinant Reg3α (rReg3α), we produced a mature rReg3α polypeptide for direct administration in l-arginine (L-Arg) induced acute pancreatitis (AP) in mice. Our results showed that rReg3α stimulated cell proliferation through Erk1/2 and p38 phosphorylation and also cyclin D1 upregulation mediated by Akt/ATF-2 signaling. Moreover, rReg3α administration significantly reduced the pancreatic damage caused by L-Arg injection, as shown in histological examination and serum amylase, lipase and C-reactive protein (CRP) assays. Not only acinar cell necrosis but also apoptosis found in the pancreas of AP mice were alleviated by rReg3α. Finally, upregulated Bcl-2 and Bcl-xL and suppressed poly (ADP-ribose) synthetase/polymerase (PARP) levels were detected as being relevant to the mechanism of rReg3α protection. We therefore conclude that rReg3α acts as a protective polypeptide against AP in mice by enhancing Bcl-2 and Bcl-xL expressions and suppressing PARP level.

Expression and characterization of recombinant interleukin-21 receptor and its targeting single-chain variable fragment antibodies selected from a human phage display library

Interleukin-21 receptor (IL-21R) is widely expressed in lymphocytes, and plays an important role in immunological cell proliferation and cytokine production. The present study aims to express a recombinant extracellular domain of human IL-21R (rhIL-21R-ECD) with high yield, and to screen the anti-IL-21R single-chain variable fragments (scFvs) from a synthetic human phage display library. The rhIL-21R-ECD, being expressed mainly as insoluble inclusion bodies in Escherichia coli BL21 (DE3), was purified and refolded. ELISA analysis showed that the refolded rhIL-21R-ECD bound to its ligand IL-21 in a concentration-dependent manner. Using a phage display technique, anti-IL-21R scFvs were screened from a naïve human phage display library by biopanning. After four rounds of panning, positive clones were isolated, sequenced, and characterized. The clone with highest activity was designated as C2. Flow cytometry analysis showed that the scFv C2 could recognize IL-21R on Jurkat cells. Furthermore, proliferation assay revealed a concentration-dependent inhibitory effect of C2 on the Jurkat cell, with fifty percent inhibitory concentration (IC(50)) of 78 nM. A human scFv antibody C2 with a high binding specificity to IL-21R was isolated and characterized. The antibody showed a concentration-dependent inhibitory effect on Jurkat cell proliferation.