Optimized Signal Peptide for Secretory Expression of Human Recombinant Somatropin in E. coli.

Purpose: The human somatropin is a single-chain polypeptide with a pivotal role in various biological processes. Although Escherichia coli is considered as a preferred host for the production of human somatropin, the high expression of this protein in E. coli results in the accumulation of protein as inclusion bodies. Periplasmic expression using signal peptides could be used to overcome the formation of inclusion bodies; still, the efficiency of each of the signal peptides in periplasmic transportation is varied and often is protein specific. The present study aimed to use in silico analysis to identify an appropriate signal peptide for the periplasmic expression of human somatropin in E. coli. Methods: A library containing 90 prokaryotic and eukaryotic signal peptides were collected from the signal peptide database, and each signal's characteristics and efficiency in connection with the target protein were analyzed by different software. The prediction of the secretory pathway and the cleavage position was determined by the signalP5 server. Physicochemical properties, including molecular weight, instability index, gravity, and aliphatic index, were investigated by ProtParam software. Results: The results of the present study showed that among all the signal peptides studied, five signal peptides ynfB, sfaS, lolA, glnH, and malE displayed high scores for periplasmic expression of human somatropin in E. coli, respectively. Conclusion: In conclusion, the results indicated that in-silico analysis could be used for the identification of suitable signal peptides for the periplasmic expression of proteins. Further laboratory studies can evaluate the accuracy of the results of in silico analysis.

The Role of Interferons in Long Covid Infection.

Although the new generation of vaccines and anti-COVID-19 treatment regimens facilitated the management of acute COVID-19 infections, concerns about post-COVID-19 syndrome or Long Covid are rising. This issue can increase the incidence and morbidity of diseases such as diabetes, and cardiovascular, and lung infections, especially among patients suffering from neurodegenerative disease, cardiac arrhythmias, and ischemia. There are numerous risk factors that cause COVID-19 patients to experience post-COVID-19 syndrome. Three potential causes attributed to this disorder include immune dysregulation, viral persistence, and autoimmunity. Interferons (IFNs) are crucial in all aspects of post-COVID-19 syndrome etiology. In this review, we discuss the critical and double-edged role of IFNs in post-COVID-19 syndrome and how innovative biomedical approaches that target IFNs can reduce the occurrence of Long Covid infection.