Production of biologically active human thioredoxin 1 protein in lettuce chloroplasts

• Published in: Plant molecular biology Vol. 76; no. 3-5; pp. 335 - 344
• Main Authors: Lim, Soon, Ashida, Hiroki, Watanabe, Rie, Inai, Koji, Kim, Yun-Soo, Mukougawa, Keiko, Fukuda, Hirokazu, Tomizawa, Ken-ichi, Ushiyama, Kei-ichi, Asao, Hiroshi, Tamoi, Masahiro, Masutani, Hiroshi, Shigeoka, Shigeru, Yodoi, Junji, Yokota, Akiho
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.07.2011; Springer Nature B.V
• Subjects: Base Sequence; Biochemistry; Biomedical and Life Sciences; Biotechnology; Chloroplasts; Chloroplasts - metabolism; DNA Primers; E coli; Gene expression; Genetic engineering; Humans; Hydrogen peroxide; Lactuca - metabolism; Leaves; Lettuce; Life Sciences; Oxidative stress; Plant biology; Plant Pathology; Plant Sciences; Plastids; Polymerase Chain Reaction; Proteins; Risk reduction; Thioredoxins - biosynthesis; Vegetables; Chloroplast transformation; Human thioredoxin-1; Plastome; Lettuce; Chloroplasts; Therapeutic protein; Transplastomic plant
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-011-9745-5

The production of human therapeutic proteins in plants provides opportunities for low-cost production, and minimizes the risk of contamination from potential human pathogens. Chloroplast genetic engineering is a particularly promising strategy, because plant chloroplasts can produce large amounts of foreign target proteins. Oxidative stress is a key factor in various human diseases. Human thioredoxin 1 (hTrx1) is a stress-induced protein that functions as an antioxidant against oxidative stress, and overexpression of hTrx1 has been shown to suppress various diseases in mice. Therefore, hTrx1 is a prospective candidate as a new human therapeutic protein. We created transplastomic lettuce expressing hTrx1 under the control of the psb A promoter. Transplastomic plants grew normally and were fertile. The hTrx1 protein accumulated to approximately 1% of total soluble protein in mature leaves. The hTrx1 protein purified from lettuce leaves was functionally active, and reduced insulin disulfides. The purified protein protected mouse insulinoma line 6 cells from damage by hydrogen peroxide, as reported previously for a recombinant hTrx1 expressed in Escherichia coli . This is the first report of expression of the biologically active hTrx1 protein in plant chloroplasts. This research opens up possibilities for plant-based production of hTrx1. Considering that this expression host is an edible crop plant, this transplastomic lettuce may be suitable for oral delivery of hTrx1.