ITLN1

What is ITLN1 protein?

ITLN1 (intelectin 1) gene is a protein coding gene which situated on the long arm of chromosome 1 at locus 1q23. Intelectin 1 (ITLN1), also known as Omentin-1, is a protein encoded by the ITLN1 gene. It was originally found in the human small intestine, but has since been widely expressed in tissues such as human adipose tissue, intestine, lung, kidney, and skin. The Intelectin 1 protein is a secreted member of the globulin family that is structurally similar to lysozyme and consists of two subunits. The ITLN1 protein is consisted of 313 amino acids and its molecular mass is approximately 35.0 kDa.

What is the function of ITLN1 protein?

It is thought to be closely related to inflammatory regulation, immune regulation, metabolic regulation and disease development. Studies have shown that ITLN1 protein plays an important regulatory role in the body's anti-inflammatory effects. It is able to regulate inflammatory responses by binding to pathogens and participate in the host's defense against microbial infections.

Fig1. (A) Omentin-1 ameliorates vascular cell dysfunction. (B) Underlying relationship among metformin/statins, omentin-1 and IS outcome. (Shiyi Lin, 2021)

ITLN1 Related Signaling Pathway

The signaling pathways involved in Intelectin 1 mainly include immune system related signaling pathways, such as Toll-like receptor (TLR) signaling pathway, NF-κB signaling pathway and inflammatory response signaling pathway. In addition, ITLN1 is also associated with apoptosis signaling pathways. In the apoptosis signaling pathway, Intelectin 1 can affect the occurrence of apoptosis by regulating the activity of Caspase family proteins.

ITLN1 Related Diseases

The ITLN1 has been linked to the development of metabolic diseases such as obesity, diabetes, cardiovascular disease and kidney disease. ITLN1 has also been found to be associated with the onset and development of tumors and inflammatory diseases.

Bioapplications of ITLN1

The ITLN1 protein is found in certain seafood products, such as cod and salmon roe, and is expected to be used in the development of functional foods and health products. Other applications are mainly in the field of medical research, particularly related to cancer.

Case study 1: Xin Huang, 2022

One of the main causes of low back pain (LBP) and degenerative musculoskeletal disorders is intervertebral disc degeneration (IVDD). Inflammation-associated senescence of Human nucleus pulposus cells (HNPCs) plays an essential function in the disease progression of IVDD. Omentin-1 is an adipokine that has been recently reported to have anti-inflammatory potential. So does Omentin-1 play an anti-inflammatory role in the development of IVDD disease?

The researchers investigated in vitro the effects of Omentin-1 on HNPCs, including the components of senescence, cell cycle and extracellular matrix (ECM) synthesis. The results showed that the addition of Omentin-1 improved IL-1β-induced senescence in HNPC. And the effect of Omentin-1 in reducing senescence of HNPCs is dependent on SIRT1. These findings suggest that Omentin-1 plays an important function in protecting HNPCs against senescence and has the potential for IVDD gene target therapy.

Fig1. Omentin-1 protein expression in HNPCs stimulated by different concentrations of IL-1β was assessed by Western blot analysis.

Fig2. Omentin-1 promoted extracellular matrix synthesis in HNPCs. HNPCs were stimulated with IL-1β (10 ng/mL), with or without Omentin-1 (150,300 ng/ml) for 24 h. Cell cycle was analyzed by flow cytometry.

Case study 2: Chi-Lam Au-Yeung, 2020

Advanced ovarian cancer usually spreads to the omentum. However, the omental cell-derived molecular determinants modulating its progression have not been thoroughly characterized. Here, this study shows that circulating ITLN1 has prognostic significance in patients with advanced ovarian cancer.

Further studies demonstrate that ITLN1 suppresses lactotransferrin's effect on ovarian cancer cell invasion potential and proliferation by decreasing MMP1 expression and inducing a metabolic shift in metastatic ovarian cancer cells. Additionally, ovarian cancer-bearing mice treated with ITLN1 demonstrate marked decrease in tumor growth rates. These data suggest that downregulation of mesothelial cell-derived ITLN1 in the omental tumor microenvironment facilitates ovarian cancer progression.

Fig3. Western blot analyses show a lower ITLN1 protein expressions in ovarian cancer-associated mesothelial cells (n = 5) compared with normal mesothelial cells.

Fig4. ITLN1 inhibits the LTF/LRP1/MMP1 signaling pathway. Western blot analyses show higher protein levels of p-ERK1/2, p-Jun (S73), total Jun, and MMP1.

ITLN1 has several biochemical functions, for example, carbohydrate binding. Some of the functions are cooperated with other proteins, some of the functions could acted by ITLN1 itself. We selected most functions ITLN1 had, and list some proteins which have the same functions with ITLN1. You can find most of the proteins on our site.

ITLN1 has direct interactions with proteins and molecules. Those interactions were detected by several methods such as yeast two hybrid, co-IP, pull-down and so on. We selected proteins and molecules interacted with ITLN1 here. Most of them are supplied by our site. Hope this information will be useful for your research of ITLN1.