Tumor Necrosis Factor-alpha human

General description

The TNFα (tumor necrosis factor α) gene is mapped to human chromosome 6p21.33. TNFα is a member of TNF superfamily. TNF-α has a palmitoyl group in the cysteine residue and is phosphorylated in the transmembrane region serine residue.

Application

Tumor Necrosis Factor-α (TNF-α) human has been used

• In induction of netting neutrophils by anti-neutrophil cytoplasmic antibody and to study its effect on platelet activation and formation of monomeric C-reactive protein.
• To study the effect of TNF-α on miR-221 and fractalkine expression.
• To induce inflammatory cell responses.
• In NF-κB luciferase reporter assay.

Tumor Necrosis Factor-a human has been used:

• as a permeability inducing agent for endothelial cell monolayer permeability assay
• as a reactive oxygen species inducer in primary rat cardiac microvascular endothelial cells (RCMVECs)
• in the activation of nuclear factor kappa B (NF-κB) in human embryonic kidney cells (HEK293), neuroblastoma SH-SY5Y cells and HeLa cells
• in the stimulation of the human keratinocyte cell line(HaCaT) and human coronary artery endothelial cells (HCAECs)

Biochem/physiol Actions

Tumor Necrosis Factor-α (TNF-α) is a potent pro-inflammatory cytokine that plays a role in the rheumatoid arthritis pathology, psoriatic arthritis (PsA) and psoriasis. It stimulates interleukins IL-1 and IL-6. Polymorphism in the TNF-α gene is associated with destructive arthropathy in PsA. The post-translational modifications in TNF-a is crucial for its functionality.

Tumore necrosis factor-α (TNF-α), also known as cachectin, is expressed as a 26 kDa membrane bound protein and is then cleaved by TNF-α converting enzyme (TACE) to release the soluble 17 kDa monomer, which forms homotrimers in circulation. TNF-α plays roles in antitumor activity, immune modulation, inflammation, anorexia, cachexia, septic shock, viral replication and hematopoiesis. TNF-α is expressed by a great variety of cells, with numerous inductive and suppressive agents. Primarily, TNF-α is produced by macrophages in response to immunological challenges such as bacteria (lipopolysaccharides), viruses, parasites, mitogens and other cytokines. TNF-α is cytotoxic for many transformed cells (its namesake activity) but in normal diploid cells, it can stimulate proliferation (fibroblasts), differentiation (myeloid cells) or activation (neutrophils). TNF-α also shows antiviral effects against both DNA and RNA viruses and it induces production of several other cytokines. Although TNF-α is used in clinical trials as an antitumor agent, Sigma′s cytokine, growth factor and hormone products are for research only. TNF-α and the related molecule TNF-β (LT-α) share close structural homology with 28% amino acid sequence identity and both activate the same TNF receptors, TNFR1 and TNFR2. Mouse and human TNF-α share 79% amino acid sequence identity. Unlike human TNF-α, the mouse form is N-glycosylated.

Preparation Note

Tumor Necrosis Factor-α (TNF-α) is expressed in human HEK 293 cells and has been shown to be predominantly a glycosylated, non-covalently linked homotrimer with a molecular mass of 51 kDa (gel filtration). Production in human 293 cells offers authentic glycosylation. Glycosylation contributes to stability in cell growth media and other applications.

Analysis Note

The specific activity was determined by the dose-dependent cytotoxity of the TNF alpha sensitive cell line L-929 in the presence of actinomycin D.