Incorporation of human growth hormone-2 into proteoliposome enhances tissue regeneration with antioxidant and anti-senescence activities.

Rejuvenation research

PubMedID: 25400020

Cho KH, Kim S. Incorporation of human growth hormone-2 into proteoliposome enhances tissue regeneration with antioxidant and anti-senescence activities. Rejuvenation Res. 2014;.
Human growth hormone-2 (GH-2) is a 191-amino acid protein also known as human placental hormone. During pregnancy, continuous secretion of GH-2 appears to have important implications for physiological adjustment to gestation, especially in controlling levels of maternal insulin-like growth factor 1. To compare the physiological activity of GH-2 between lipid-free and lipid-bound states, GH-2 was expressed and incorporated into proteoliposome. GH-2 was expressed and purified using pET28(a)-GH-2 vector in an E. coli system. Purified GH-2 was then characterized and synthesized into rHDL. Expression yield of GH-2 was 20-30 mg by BL21 (DE3) cells in 1 L of LB broth. Purified GH-2 of at least 98% purity (23 kDa) was incorporated into reconstituted high-density lipoprotein (rHDL) with human apolipoprotein (apo)A-I and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) at a 1:1:95 (GH-2:apoA-I:POPC) molar ratio. Structural analysis revealed that GH-2 had 44% ?-helix content and a wavelength maximum fluorescence (WMF) of 349 nm in a lipid-free state. In a lipid-bound state, WMF of GH-2 was around 4 nm blue-shifted (345 nm) with 50% of ?-helix content. The lipid-bound GH-2 showed enhanced anti-atherosclerotic activity and anti-senescence activity with inhibition of fructose mediated glycation. Fin regeneration experiment using zebrafish (17-weeks-old, n=9) showed that lipid-bound GH-2 enhanced regeneration efficiency by 44% compared to native GH-2 (in lipid-free state) without any notable side effects. GH-2 has antioxidant activity to enhance tissue regeneration as well as to exert anti-diabetic activity. Incorporation of GH-2 into rHDL can enhance structural stability and tissue regeneration efficiency in vertebrate models, indicating a synergetic effect between GH-2 and apoA-I in rHDL.