Team:BGU Israel/Project/Hormone Workshop

Adiponectin is an adipocyte derived protein hormone showing insulin - sensitizing effect and has an important role in lipid and glucose metabolism regulation. Hypoadiponectemia (low levels of serum Adiponectin) is highly related with occurrence of abdominal obesity, insulin resistance, type 2 diabetes, and the metabolic syndrome. Adiponectin forms multimeric complexes that combine via its collagen domain to create three major oligomeric forms: a low molecular weight (LMW) trimer, a middle - molecular weight (MMW) hexamer, and high molecular weight (HMW) 12-18- mer Adiponectin. The form showing the most relevant properties considering insulin sensitivity and protection from diabetes is the HMW form of the hormone (Kadowaki et al., 2006).

Figure 1. Adiponectin oligomeric forms

When one is diagnosed with the metabolic syndrome's symptoms and shows low levels of serum Adiponectin, an efficient treatment could be a pill or a shot containing the active HMW form of Adiponectin hormone. However, there is no known efficient synthetic method to produce the desired multimer structure of the hormone. It has been shown that overexpression of the enzyme DsbA-L (disulfide-bond A oxidoreductase - like), promotes Adiponectin multimerization, while suppressing its expression by RNAi markedly and selectively reduced Adiponectin levels and secretion in adipocytes (Liu et al., 2008).
In order to synthesize the HMW form of Adiponectin, we intend to introduce overexpression of both Adiponectin and DsbA-L in our model cell line HepG2 (human hepatocellular carcinoma). This is expected to produces high levels of HMW Adiponectin while relying on the natural hormone secreting ability of hepatocytes and excretion tags on the hormone itself.
In the future, we intend to attach the hormone to an inducible system to allow for more control on the proteins synthesis.

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