PBJ | New advances in lettuce chloroplast transformation: the use of plant cell-expressed proteins for early intervention and treatment of hemophilia B

Hemophilia B is a recessive genetic disease caused by the lack of coagulation factor FIX on the X chromosome.

In the course of its treatment, the formation of anti-drug antibodies (ADA) is one of the main problems that are difficult to overcome.

Because many drugs that promote blood coagulation often antagonize FIX in inappropriate organs and periods, and cause allergic reactions, scientists have tried a variety of techniques for a long time in the past, but have not yet found a suitable solution.
Program.

In recent years, through genetic engineering, scientists have begun to use plant cells to develop and express medical supplies.
For example, eating peanuts expressing anti-allergic agents can prevent peanut allergies.

In addition, some hospitals have begun to adopt treatment plans that use plant cells to express drug molecules for initial intervention.

Therefore, expressing the coagulation factor FIX in plants and fusing with appropriate transporters to release them in appropriate organs and timing is a potential solution for the treatment of hemophilia B.

Henry Daniell's team from Pennsylvania State University has long been engaged in the creation of a heterologous protein expression system for plant cells.

In the early stage, they successfully developed an oral preparation of plant cells that can treat animal hemophilia through chloroplast transformation.

Recently, they successfully created a lettuce that can express FIX without antibiotic markers.

Figure 1: Creation of expression vector without resistance marker and transgenic progeny (because the 5'and 3'of the resistance marker expression element can be recombined into a loop, it will be cleared after recombination) The FIX expressed in this lettuce is fused The transport factor CTB (cholera toxin B subunit) can perform protein cleavage and function in the body at the right time.

Due to the use of the optimal chloroplast transformation system and expression vector, the copy number of the FIX-CTB fragment is very high in lettuce leaves, making it possible for stable protein expression in both T1 and T2 generation plants (Figure 1).

After testing, the content of the target protein can reach 1.
0-1.
5 mg per 1 gram of freeze-dried leaves.

Figure 2: The trial and prospect of clinical application of plant cell drug products are further.
They used freeze-dried leaves to feed SD rats, with the content ranging from 0.
25mg/kg to 2.
5mg/kg, and no toxicity and allergic reactions were found.

The feeding experiment of beagle dogs also showed no obvious toxicity and allergic reactions, indicating that taking the plant cells expressing the drugs can effectively avoid allergic reactions caused by the direct use of drugs, and has a great promotion effect on the treatment of hemophilia B ( figure 2).

Original link: https://onlinelibrary.
wiley.
com/doi/epdf/10.
1111/pbi.
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