The generation of the recombinant human IL6 with an N-terminal His-tag in an E. coli expression system involves several steps. First, the gene fragment encoding the full length of the mature human IL6 protein (30-212aa), fused with the sequence for the N-terminal His-tag, is cloned into an expression vector and transformed into E. coli cells. After inducing protein expression, the cells are lysed to release the recombinant IL6 protein, which is purified using affinity chromatography. The purity of the protein is assessed by SDS-PAGE, exceeding 85%.
Human IL6 regulates multiple cellular processes through signaling pathways involving a shared gp130 receptor [1]. IL6 activates the transcription of genes such as haptoglobin, hemopexin, and C-reactive protein in human hepatoma cell lines [2]. Additionally, IL6 is an essential inflammatory cytokine with diverse functions in immune responses and the regulation of tumor growth [3]. It has been implicated in various conditions, including chronic obstructive pulmonary disease (COPD), where it mediates the acute phase response and upregulates C-reactive protein at the transcriptional level [4]. IL6 has also been associated with breast cancer development, where its gene expression may serve as a marker for basal breast cancer growth and metastasis [5].
Furthermore, IL6 is involved in insulin resistance and obesity, as studies have shown that overexpression of human IL6 can enhance insulin sensitivity and leptin action, preventing diet-induced obesity without causing systemic or tissue inflammation [6]. Research has also found that IL6 contributes to resistance against apoptosis in lung fibroblasts, affecting the expression of anti-apoptotic and pro-apoptotic proteins [7]. IL6 signaling can be modulated by various factors, such as Zinc finger protein 580 (Zfp580), which has been identified as a mediator of the effects of lithium on IL6 signaling [8].
References:
[1] A. Widjaja, S. Chothani, & S. Cook, Different roles of interleukin 6 and interleukin 11 in the liver: implications for therapy, Human Vaccines & Immunotherapeutics, vol. 16, no. 10, p. 2357-2362, 2020. https://doi.org/10.1080/21645515.2020.1761203
[2] S. Akira, H. Isshiki, T. Sugita, O. Takahashi, S. Kinoshita, Y. Nishioet al., A nuclear factor for il-6 expression (nf-il6) is a member of a c/ebp family., The Embo Journal, vol. 9, no. 6, p. 1897-1906, 1990. https://doi.org/10.1002/j.1460-2075.1990.tb08316.x
[3] W. Lu, Y. Dong, Q. Cui, Y. Wang, X. Yang, X. Caiet al., High expression of citron kinase contributes to the development of esophageal squamous cell carcinoma, Frontiers in Genetics, vol. 12, 2021. https://doi.org/10.3389/fgene.2021.628547
[4] J. He, M. Foreman, K. Shumansky, X. Zhang, L. Akhabir, D. Sinet al., Associations of il6 polymorphisms with lung function decline and copd, Thorax, vol. 64, no. 8, p. 698-704, 2009. https://doi.org/10.1136/thx.2008.111278
[5] E. Fertig, E. Lee, N. Pandey, & A. Popel, Analysis of gene expression of secreted factors associated with breast cancer metastases in breast cancer subtypes, Scientific Reports, vol. 5, no. 1, 2015. https://doi.org/10.1038/srep12133
[6] T. Allen and M. Febbraio, Il6 as a mediator of insulin resistance: fat or fiction?, Diabetologia, vol. 53, no. 3, p. 399-402, 2009. https://doi.org/10.1007/s00125-009-1627-x
[7] Y. Xia, L. Cheng, D. Yang, & H. Luo, Identification of key modules and hub genes associated with lung function in idiopathic pulmonary fibrosis, Peerj, vol. 8, p. e9848, 2020. https://doi.org/10.7717/peerj.9848
[8] C. Hoffmann, M. Kuffner, L. Koschützke, S. Lorenz, J. Lips, P. Boehm‐Sturmet al., Zfp580 inactivation as a new therapeutic target to enhance recovery after stroke in mice, Journal of Cerebral Blood Flow & Metabolism, vol. 43, no. 8, p. 1400-1418, 2023. https://doi.org/10.1177/0271678x231168499
