Production and characterization of recombinant human leukemia inhibitory factor and evaluation of anti-fertility effects of rabbit anti-rhLIF in Balb/c mice

Study the effect of recombinant leukemia inhibitory factor on maintenance of pregnancy and frequency of regulatory T cells in abortion-prone mice

Recurrent spontaneous abortion (RSA) can have a significant impact on a woman's quality of life. Understanding the mechanisms behind abortion is crucial for developing potential treatments. Among various models of abortion, the CBA/J(♀) × DBA/2J(♂) model stands out as the most extensively studied. This model reveals the influence of an altered immune system on resorption during pregnancy. The leukemia inhibitory factor (LIF) holds considerable importance as a secretory glycoprotein essential for successful implantation. Regulatory T cells (Tregs) have been found to produce high levels of LIF in both mice and humans. LIF plays a vital role in the development of Tregs by upregulating the expression of the Foxp3 transcription factor while downregulating the expression of RORγt. To investigate the impact of recombinant LIF (rLIF) on pregnancy maintenance and Treg cell frequency in abortion-prone (AP) mice, a specific recombinant protein was used in this study. The AP group consisted of CBA/J(♀) × DBA/2J(♂) mice, while the control group comprised CBA/J(♀) × BALB/c(♂) mice. Intraperitoneal injections of rLIF were administered to the AP group on the third day of pregnancy, and its effects on Treg cell frequency and pregnancy maintenance were examined during this period. Following rLIF injections on the fourteenth day of pregnancy, the expression of Foxp3 significantly increased in AP mice (p = 0.02,0.008). Additionally, AP mice injected with rLIF demonstrated a significant reduction in resorption rate (p = 0.01) and a notable increase in birth rate (p = 0.01,0.0005). These findings provide new insights into the potential benefits of LIF in treating RSA patients.

The potential of cold-shock promoters for the expression of recombinant proteins in microbes and mammalian cells

BACKGROUND

Low-temperature expression of recombinant proteins may be advantageous to support their proper folding and preserve bioactivity. The generation of expression vectors regulated under cold conditions can improve the expression of some target proteins that are difficult to express in different expression systems. The cspA encodes the major cold-shock protein from Escherichia coli (CspA). The promoter of cspA has been widely used to develop cold shock-inducible expression platforms in E. coli. Moreover, it is often necessary to employ expression systems other than bacteria, particularly when recombinant proteins require complex post-translational modifications. Currently, there are no commercial platforms available for expressing target genes by cold shock in eukaryotic cells. Consequently, genetic elements that respond to cold shock offer the possibility of developing novel cold-inducible expression platforms, particularly suitable for yeasts, and mammalian cells.

CONCLUSIONS

This review covers the importance of the cellular response to low temperatures and the prospective use of cold-sensitive promoters to direct the expression of recombinant proteins. This concept may contribute to renewing interest in applying white technologies to produce recombinant proteins that are difficult to express.

Production of biologically active recombinant buffalo leukemia inhibitory factor (BuLIF) in Escherichia Coli

Background

Leukemia inhibitory factor (LIF) is a multifunctional cytokine which plays multiple roles in different biological processes such as implantation, bone remodeling, and hematopoiesis. The buESCs are difficult to culture due to lack of proper understanding of the culture conditions. LIF is one of the important factors which maintain the pluripotency in embryonic stem cells and commercial LIF from murine and human origin is used in the establishment of buffalo embryonic stem cells (buESCs). The LIF from a foreign origin is not able to maintain pluripotency and proliferation in buESCs for a long term which is contributed by difference in the binding sites on LIF; therefore, culture medium supplemented with buffalo-specific LIF may enhance the efficiency of buESCs by improving the environment of culture conditions. The high cost of LIF is another major drawback which restricts buESCs research, thus limits the scope of buffalo stem cell use. Various methods have been developed to produce human and murine LIF in prokaryotic system. However, Buffalo leukemia inhibitory factor (BuLIF) has not been yet produced in prokaryotic system. Here, we describe a simple strategy for the expression and purification of biologically active BuLIF in Escherichia coli (E. coli).

Results

The BuLIF cDNA from buffalo (Bubalus bubalis) was cloned into pET22b(+) and expressed in E. coli Lemo-21(DE3). The expression of BuLIF was directed into periplasmic space of E. coli which resulted in the formation of soluble recombinant protein. One step immobilized metal affinity chromatography (IMAC chromatography) was performed for purification of BuLIF with ≥ 95% of homogeneity. The recombinant protein was confirmed by western blot and identified by mass spectroscopy. The biological activity of recombinant BuLIF was determined on murine myeloid leukemic cells (M1 cells) by MTT proliferation assay. The addition of BuLIF increased the reduction of MTT by stimulated M1 cells in a dose-dependent manner. The BuLIF induced the formation of macrophage like structures from M1 cells where they engulfed fluorescent latex beads. The recombinant BuLIF successfully maintained pluripotency in buffalo embryonic stem cells (buESCs) and were positive for stem cells markers such as Oct-4, Sox-2, Nanog, and alkaline phosphatase activity.

Conclusions

The present study demonstrated a simple method for the production of bioactive BuLIF in E. coli through single step purification. BuLIF effectively maintained buffalo embryonic stem cells pluripotency. Thus, this purified BuLIF can be used in stem cell study, biomedical, and agricultural research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43141-022-00328-1.