Functional exosome production system


In this system, we applied ODE(ordinary differential equation)- system to predict the production of the exosome and other target proteins. Also, the interactions among them are inclusive in the time-amount model.


1. Production of exosome is mainly associated with booster protein.
2. mRNA and proteins are limited by natural degradation.
3. Amount of proteins stored into exosome is proportional to the size of each exosome, so size of exosome can be ignored.
4. The packaging of protein to exosome and finishing of translation happen simultaneously because the interval is too short to take into account.

Parameters Definitions Value Units Note
a Translational rate per amino acid 720 Amino acids residues *min-1
TCrb transcription rate of RVG-Lamp2b 0.314 umol *min-1
TCc3 transcription rate of CX36 0.42 umol *min-1
TCce transcription rate of CD63-L7AE 0.37 umol *min-1
TCdrug transcription rate of drug mRNA 0.46 umol *min-1
TCssn Maximum transcription rate of STEAP3-SCD4-NadB 0.15 umol *min-1
TCne transcription rate of nsMase 0.24 umol *min-1
TCcm2 transcription rate of CD63-MS2 0.41 umol *min-1
LRB Length of RVG-lamp2b 469 Amino Acid residues
LC3 Length of Cx36 320 Amino Acid residues
LCE Length of CD63-L7AE 367 Amino Acid residues
LCM2 Length of CD63-MS2 378 Amino Acid residues
LS3 Length of STEAP3 488 Amino Acid residues
LS4 Length of SCD4 198 Amino Acid residues
LNB Length of NadB 331 Amino Acid residues
LNE Length of nsMase 655 Amino Acid residues
dmRNA Decay rate of mRNA 0.41 umol *min-1
TCssn Maximum transcription rate of STEAP3-SCD4-NadB 0.139 min-1 2016 IGEM imperial college
C Packaging rate by Exosome 0.6 min-1
d_prot Degradation rate of protein 1.39E-05 min-1 2016 IGEM imperial college
K11/K12/K13/K14 The rate of booster protein facilitate exosome biogenesis 0.15 min-1
K15 Combination rate between CD63-L7AE and drug mRNA 0.08 min-1
K17 transcription rate of CD63-MS2 0.3 min-1
dce-drug Maximum transcription rate of STEAP3-SCD4-NadB 1.39E-05 min-1 Same as degradation rate of other proteins
K18 Disassociation of CD63-L7AE and drug mRNA 3x10-4
K19 Disassociation of CD63-L7AE and drug mRNA 2x10-4
K0 7.9x103

Figure1: state value of target proteins

In this figure, we can see the non-packaging proteins (NadB, nsMase, Steap3) are tend to overexpress, and packaging protein (CX36, CD63-L7AE, SCD4, CD63-L7AE-drug) reached a producing-consuming balance

Figure2: individual demonstration of booster protein


Figure3: individual demonstration of packaging-protein


Figure4: diagram of Exosome production


Figure5:Two version of the functional exosome.

As shown in figure 4, with the help of the booster, our output of functional exosome is significantly increasing. In our design of ExoB1, we add the nsMase as one of our booster members, which genders the amount of exosome into a higher level according to our model results.

In figure5, CM2-loaded exosome which has a low level of toxicity produce relatively less amount of exosome compared to the CE-loaded exosome. That is because L7AE capture the drug-mRNA more efficiently.

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Xi'an Jiaotong-Liverpool University

111 Ren'ai Road, Suzhou, China




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