Patent Publication Number: US-2021169802-A1

Title: Extracellular vesicles derived from recombinant microorganism including polynucleotide encoding target protein and use thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2018-0052157, filed on May 4, 2018, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     TECHNICAL FIELD 
     Field 
     One or more embodiments relate to extracellular vesicles derived from a recombinant microorganism including a polynucleotide encoding a target protein, and a use thereof. 
     BACKGROUND ART 
     Most animal cells secrete extracellular vesicles (EVs) that have various sizes and components and originate from cells. Both prokaryotes and eukaryotes are known to secrete EVs. 
     EVs are membrane-structured vesicles having a size of about 20 nm to about 5 μm in diameter. EVs are heterogeneous in size and composition, and include a great number of different species such as exosomes (about 30 nm to about 100 nm), ectosomes, microvesicles (about 100 nm to about 1,000 nm), microparticles, outer membrane vesicles, and the like. The characteristics of EVs are affected by the characteristics of the origin cells. 
     Meanwhile, intracellular substances (for example, DNA, RNA, proteins, and the like) may be naturally loaded into EVs and extracellularly secreted. EVs have high biocompatibility due to having the same component as that of bio-membranes, and are as small as nano-sized, and thus have high mass transfer efficiency. Therefore, research is ongoing on delivery of drugs using EVs instead of using existing delivery systems such as liposomes, and the like. However, when a target protein is loaded into EVs, the efficiency of loading of the target protein into the EVs is low. Therefore, there is a need for a technique capable of stably loading a target protein into EVs with high efficiency. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     One or more embodiments include extracellular vesicles (EVs) derived from a recombinant microorganism including one or more polynucleotides encoding one or more target proteins, wherein the recombinant microorganism is a lactic acid bacterium or a yeast. 
     One or more embodiments include EVs isolated from the above-described recombinant microorganism. 
     One or more embodiments include a composition for delivering one or more target proteins to a subject, which includes EVs derived from the above-described recombinant microorganism as active ingredients and a carrier. 
     One or more embodiments include a method of treating a disease of a subject, including administering the composition to the subject. 
     One or more embodiments include a method of applying a cosmetic to a subject, including administering the composition to the subject. 
     One or more embodiments include a method of producing EVs, including: culturing the above-described microorganism to obtain a culture; and isolating EVs from the culture. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. 
     Solution to Problem 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. 
     An aspect of an embodiment provides extracellular vesicles (EVs) derived from a recombinant microorganism including one or more polynucleotides encoding one or more target proteins, wherein the recombinant microorganism is a lactic acid bacterium or a yeast. 
     The target protein may be linked to a signal peptide, i.e., it may be a fusion protein of a signal peptide and the target protein. The recombinant microorganism may load the target protein into extracellular vesicles (EVs) in an increased amount. In this case, the recombinant microorganism may have an increased EV-loading ability compared to a recombinant microorganism including one or more polynucleotides encoding one or more target proteins not having a signal peptide. The EV-loading ability refers to a degree to which the target protein is included in EVs or a degree to which the target protein is expressed in EVs. The EV-loading ability may refer to a loading ability compared to a parent microorganism not including a polynucleotide encoding a target protein. 
     The signal peptide may be encoded by the nucleotide sequence of SEQ ID NO: 4, or any one of the amino acid sequences of SEQ ID NOS: 21 to 60, or a sequence including or similar to the any one thereof. 
     In the recombinant microorganism, the lactic acid bacterium may belong to the genus selected from the group consisting of  Lactobacillus, Lactococcus,  and  Bifidobacterium.  The lactic acid bacterium may be  Lactobacillus paracasei, Lactobacillus brevis,  or  Lactobacillus plantarum.    
     In the recombinant microorganism, the yeast may belong to the genus selected from the group consisting of  Saccharomyces, Pichia,  and  Hansenula.  The genus  Saccharomyces  may be  S. cerevisiae.  The genus  Pichia  may be  Pichia pastoris,  and the genus  Hansenula  may be  Hansenula polymorpha.    
     In the recombinant microorganism, the target protein may be a growth factor, a cytokine, an antibody, an enzyme, an inhibitory protein, or a fragment thereof. The growth factor may be a fibroblast growth factor. The target protein may be selected from the group consisting of a fibroblast growth factor (FGF), an epidermal growth factor (EGF), a hepatocyte growth factor (HGF), an insulin-like growth factor (IGF), a placenta growth factor (PGF), a platelet-derived growth factor (PDGF), a transforming growth factor (TGF), a vascular endothelial growth factor (VEGF), thioredoxin (TRX), interleukin-1 (IL-1), IL-10, IL-22, IL-13, and a tumor necrosis factor (TNF). The target protein may be, for example, selected from the group consisting of IL-22, EGF, IGF1, FGF1 (hereinafter, also referred to as an acidic fibroblast growth factor (aFGF)), FGF2 (hereinafter, also referred to as a basic fibroblast growth factor (bFGF)), FGF7 (hereinafter, also referred to as a keratinocyte growth factor (KGF)), TGFa, and TRX. 
     In the recombinant microorganism, the signal peptide may be a signal peptide encoded by the nucleotide sequence of SEQ ID NO: 4, or any one of amino acid sequences of SEQ ID NOS: 21 to 60. A gene encoding the signal peptide may be linked such that the signal peptide is linked to the N-terminus of the target protein. The signal peptide may be naturally occurring or heterologous to the target protein. The target protein may be a heterologous protein to the recombinant microorganism. The recombinant microorganism may express the target protein. The target protein may be loaded into EVs in a state in which the signal peptide is cleaved. The target protein may be loaded on membranes of EVs or into EVs. 
     In the recombinant microorganism, the polynucleotide encoding a target protein may be expressible. The polynucleotide may be operably linked to a transcriptional control sequence. The transcriptional control sequence may be a promoter, an operator, an enhancer, or a terminator. The polynucleotide may be operably linked to a translational control sequence. The translational control sequence may be a ribosome binding site or a ribosome entry site sequence. The polynucleotide may be integrated into the genome of the microorganism or may be independently present. The polynucleotide may be included in a vector. The vector may be an expression vector. The vector may be a plasmid or a viral vector. 
     Another aspect of an embodiment provides EVs isolated from the above-described recombinant microorganism. 
     Another aspect of an embodiment provides a composition for delivering one or more target proteins to a subject, which includes extracellular vesicles derived from the above-described recombinant microorganism as active ingredients and a carrier. 
     In the embodiments regarding the recombinant microorganism and the composition, the EVs may be isolated from a culture broth of the microorganism. That is, the extracellular vesicles may be extracellularly secreted. The EVs may have an average diameter of about 20 nm to about 500 nm, for example, about 20 nm to about 200 nm or about 100 nm to about 200 nm. The EVs may include the target protein. The target protein may be located on membranes of the EVs or in the EVs. 
     The EVs may be isolated by any method capable of isolating EVs from a culture broth. For example, the EVs may be isolated by centrifugation, ultracentrifugation, filtration through a filter, ultrafiltration, gel filtration chromatography, ion exchange chromatography, precipitation, immunoprecipitation, pre-flow electrophoresis, capillary electrophoresis, or a combination thereof. The isolation method may include washing for removing impurities, concentration, and the like. The EVs may be produced using a method of separating the EVs, which will be described below. The EVs may be produced by ultrafiltration of the microorganism culture broth by using an ultrafiltration filter having a cutoff of 10 kD or more, for example, 50 kD or more, 100 kD or more, 300 kD or more, or 500 kD or more. The EVs may be precipitated by ultracentrifugation of the microorganism culture broth at 100,000×g or higher. The isolation may be performed using a method of producing EVs according to a seventh embodiment, which will be described below. 
     In the embodiment regarding the composition, the carrier may be physiologically acceptable, for example, pharmaceutically or cosmetically acceptable. The carrier may include saline, sterile water, Ringer&#39;s solution, buffer, cyclodextrin, a dextrose solution, a maltodextrin solution, glycerol, ethanol, liposomes, or a combination thereof, which are generally used. In addition, the carrier may include an antioxidant, a diluent, a dispersant, a surfactant, a binder, a lubricant, or a combination thereof. 
     The composition may be in a dosage form for oral or parenteral administration. The dosage form for parenteral administration may be a dosage form for topical administration. The dosage form for topical administration may be a dosage form for administration to the skin or the mucosa. The dosage form for parenteral administration may be a solution, a suspension, an emulsion, a dermatologic agent, a spray, or a puff. 
     The composition may be administered to a subject by skin application, mucosal application, nasal administration, or the like. 
     A suitable dose may vary depending on body weight, age, and gender of a patient, health conditions, diet, administration time, an administration method, excretion rate, the severity of a disease, and the like. A daily dose refers to an amount of an active ingredient sufficient to treat symptoms of a disease relieved by administering the composition to a subject in need of treatment. The dose may range from about 0.01 mg/day to 1,000 mg/day, or about 0.01 mg/day to about 500 mg/day, with respect to an adult with a body weight of 70 kg, and may be administered once to several times a day at predetermined time intervals. 
     The composition may be a cosmetic composition. The cosmetic composition may include ingredients commonly used in cosmetic compositions. The cosmetic composition may include general adjuvants such as an antioxidant, a stabilizer, a solubilizer, vitamins, a pigment, and a flavor, and carriers. 
     The cosmetic composition may be in the form of a solution, a suspension, an emulsion, a paste, a gel, a cream, a lotion, powder, oil, a powder foundation, an emulsion foundation, a wax foundation, or a spray. The cosmetic composition may be in the form of a nutritional cream, an astringent lotion, a soft lotion, a lotion, an essence, a nutritional gel, or a massage cream. 
     The composition may be used to promote the growth of fibroblasts or keratinocytes or collagen synthesis, in a subject. The composition may be used to prevent skin aging or alleviating wrinkles. In this case, the target protein may be a growth factor. 
     The composition may be delivered such that the target protein is topically delivered to the subject. The composition may be delivered transdermally, intradermally, orally, transmucosally, or intramucosally. 
     In the composition, the individual may be a mammal. The mammal may be a human, a dog, a cat, a horse, or a pig. 
     Another aspect of an embodiment provides a method of treating a disease of a subject, including administering the composition to a subject. The individual may be a mammal. The mammal may be a human, a dog, a cat, a horse, or a pig. The disease may be an inflammatory disease, wound, atopic dermatitis, psoriasis, or acne. 
     Another aspect of an embodiment provides a method of applying a cosmetic to a subject, including administering the composition to a subject. The administration may be performed by application to aged skin or wrinkled skin areas. The application of the cosmetic may be intended to alleviate aged skin or wrinkled skin. 
     Another aspect of an embodiment provides a method of producing EVs, including: 
     culturing the above-described recombinant microorganism to obtain a culture; and isolating EVs from the culture. 
     The culture may be incubation in a medium useful for the growth of the microorganism. The culture may be performed under conditions known to be suitable for lactic acid bacteria or yeast, for example, temperature and stirring conditions. 
     The isolation of the EVs from the culture may be performed using any method of isolating EVs from a culture. 
     The isolation may include: centrifuging the culture to obtain a supernatant; filtering the supernatant; and ultracentrifuging the filtrate to obtain a precipitate. 
     In the isolation, the centrifugation may be performed at about 1,000×g to about 20,000×g. In the filtration, the filtration may be filtration using an ultrafiltration filter. The filtration may be ultrafiltration of the supernatant using an ultrafiltration filter having a cutoff of 10 kD or more, for example, 50 kD or more, 100 kD or more, 300 kD or more, or 500 kD or more. In the ultracentrifugation of the filtrate to obtain a precipitate, the ultracentrifugation may be performed at 100,000×g or higher, for example, about 100,000×g to about 200,000×g. 
     The method may further include suspending the precipitate. 
     It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. 
     While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which: 
         FIG. 1  illustrates an expression vector for expressing target proteins in yeast cells; 
         FIG. 2  illustrates levels of target proteins expressed in a supernatant and extracellular vesicles (EVs) derived from  S. cerevisiae  transformed with p416G-MF-hEGF1 (IGF1, FGF1, FGF2, TGF alpha, and TRX); 
         FIG. 3  illustrates levels of target proteins expressed in a supernatant and EVs derived from  S. cerevisiae  transformed with p416G-hFGF1, p416G-MF-hFGF1, p416G-hTRX and p416G-MF-hTRX; 
         FIG. 4  illustrates an effect of growth factor-containing EVs derived from yeasts on cell proliferation; 
         FIG. 5  illustrates the production of IL-10 in cells treated with  S. cerevisiae  derived IL-22-containing EVs or IL-22-free EVs; 
         FIG. 6  illustrates results of observing the degree of binding of  S. cerevisiae  derived 
       EVs labeled by CFSE-labeled EVs with cells through cell flow analysis; 
         FIG. 7  illustrates results of measuring toxicity of yeast-derived EVs to the skin; 
         FIG. 8  illustrates the size and concentration distribution of EVs derived from transformed lactic acid bacteria; 
         FIG. 9  illustrates western blotting results of EV solutions; 
         FIG. 10  illustrates western blotting results of EVs derived from LMT1-21 transformed with recombinant pMT172 including a gene encoding FGF1 that was fused or not fused with a signal peptide gene; 
         FIG. 11  illustrates an effect of growth factor-containing EVs derived from lactic acid bacteria on cell proliferation; 
         FIG. 12  illustrates production of IL-10 in cells treated with IL-22-containing EVs derived from LMT1-21 or IL-22-free EVs;; 
         FIG. 13  illustrates results of observing the degree of fusion of CFSE-labeled EVs with cells through cell flow analysis; 
         FIG. 14  illustrates results of measuring the toxicity of yeast-derived EVs to the skin; 
         FIG. 15  illustrates results of observing the effect of growth factors which are contained in EVs or naked growth factors on the epidermal cell proliferation or collagenesis; 
         FIG. 16  illustrates result of stability test for EGFs which are contained in EVs or naked EGFs; and 
         FIG. 17  illustrates result of stability test for FGF2s which are contained in EVs or naked FGF2s. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, the present disclosure will be described in further detail with reference to the following examples. However, these examples are provided for illustrative purposes only and are not intended to limit the scope of the present disclosure. 
     EXAMPLE 1 
     Yeast Cell-Derived Extracellular Vesicles (EVs) 
     Recombinant yeast expressing a target protein was prepared and EVs were isolated from the yeast. Detailed procedures are as follows. Saccharomyces cerevisiae was used as the yeast cells. 
     1. Production of Expression Vector 
       FIG. 1  illustrates an expression vector for expressing target proteins in yeast cells. 
     The expression vector was constructed using a sequence of plasmid pRS416 GPD (SEQ ID NO: 1), and the target proteins are hEGF1, hIGF1, hFGF1, hFGF2, hTGF alpha, and hTRX. The hEGF1, hIGF1, hFGF1, hFGF2, hTGF alpha, and hTRX proteins respectively have the amino acid sequences of SEQ ID NOS: 14, 15, 12, 13, 17, and 18, and these proteins may be encoded by the nucleotide sequences of SEQ ID NOS: 5, 6, 7, 8, 10, and 11, respectively. FGF7 may have the nucleotide sequence of SEQ ID NO: 9, and the amino acid sequence thereof may be the amino acid sequence encoded by the nucleotide sequence of SEQ ID NO: 9. 
     The vector of  FIG. 1  was named p416G-MF-hEGF1 (IGF1, FGF1, FGF2, TGF alpha, and TRX) according to the target proteins. 
     First, codon-optimized target protein genes, i.e., human EGF1, IGF1, FGF1, FGF2, TGF alpha, and TRX genes, were synthesized according to the codon usage frequency of  S. cerevisiae  by MicroGene upon request. Each gene was constructed into the expression vector of  FIG. 1  by using p416GPD vector (ATCC87360) (SEQ ID NO: 1). The expression vector of  FIG. 1  includes a sequence in which a polynucleotide encoding a mating factor alpha-1 signal peptide (MF) (SEQ ID NO: 4) of S. cerevisiae is linked to upstream of the target protein gene. As a control, a gene to which a polynucleotide encoding a signal peptide (MF) (SEQ ID NO: 4) was not linked was used. In addition, a vector was constructed in the same manner as described above, except that p426GPD vector (ATCC 87361) (SEQ ID NO: 2) was used instead of the p416GPD vector (ATCC87360). The p416GPD vector is a vector present in cells with a low copy and the p426GPD vector is a vector present in cells with a high copy. In p416GPD and p426GPD, GPD represents the nucleotide sequence of the promoter GPD (SEQ ID NO: 3). 
     In  FIG. 1 , the vector includes a CEN/Ars sequence, which is the origin of replication of  S. cerevisiae,  an ampicillin resistance gene (Ampr) sequence, a ColE1 ori sequence, which is a sequence of the origin of replication of  E. coli,  a promoter GPD sequence, which is a promoter sequence of  S. cerevisiae,  a ScCYC term sequence, which is a CYC terminator sequence of  S. cerevisiae,  an F1 ori sequence, which is the origin of replication of bacteriophages, a promoter of S. cerevisiae, ORF, a terminator sequence (ScURA3p-URA3). 
     2. Expression of Target Protein in Yeast 
     Each of the p416G-MF-hEGF1 (IGF1, FGF1, FGF2, TGF alpha, and TRX) was transformed into a  S. cerevisiae  CEN. PK2-1 strain according to a LiCl method. The obtained transformed strain was primarily cultured for 1 day in 2 mL of a minimal uradrop out medium (6.7 g/L of yeast nitrogen base without amino acids (Sigma-Aldrich: Cat. No. Y0626), 1.92 g/L of yeast synthetic drop-out without uracil (Sigma-Aldrich: Cat. No. Y1501), and 2% (w/v) of glucose), and the cultured strain was inoculated into 15 mL of a minimal ura-drop out medium containing 1% of casamino acids at an initial OD 600  of 0.5, followed by main culture. The main culture was performed at 30° C. while stirring at 220 rpm for 2 days, and a sample group directly using a supernatant from which microbial bodies were removed was prepared. In addition, the supernatant was filtered using a 100 kDa cut-off membrane (Amicon Ultra-15 Centrifugal Filter Unit with Ultracel-10 membrane (100 K), Millipore: Cat. No. UFC910024) to obtain a concentrated filtrate, and the filtrate was ultracentrifuged at 150,000×g for 2 hours to isolate EVs and the EVs were suspended in 1 ml of PBS. At this time, western blotting was performed on the supernatant and the obtained EVs sample to confirm expression levels of the proteins. 
       FIG. 2  illustrates levels of target proteins expressed in a supernatant and extracellular vesicles (EVs) isolated from S. cerevisiae transformed with p416G-MF-hEGF1 (IGF1, FGF1, FGF2, TGF alpha, and TRX). Lanes 1 and 2 are western blotting images showing an expression level of a fusion protein in which each target protein was linked to a signal peptide (MF). Lane 1 includes all proteins expressed in yeast cells and isolated from the culture broth, i.e., all target proteins loaded or not loaded in EVs. Lane 2 represents only the target proteins loaded in the EVs. As illustrated in  FIG. 2 , in the all six experimental groups, the respective target proteins are loaded in the EVs in significantly increased amounts. 
       FIG. 3  illustrates levels of target proteins expressed in a supernatant and EVs isolated from  S. cerevisiae  transformed with p416G-hFGF1, p416G-MF-hFGF1, p416G--hTRX and p416G-MF-hTRX. That is,  FIG. 3  illustrates the degree of capturing by EVs according to the presence or absence of a signal peptide. 
     Lane 1 represents target proteins in EVs obtained from a culture broth of the strain expressed without a signal peptide, and lane 2 represents the expression of target proteins in EVs obtained from a culture broth of the strain expressed and secreted by a signal peptide. As illustrated in  FIG. 3 , the amounts of target proteins expressed in EVs when expressed and extracellularly secreted were significantly larger, i.e., 2.648 ng for FGF1 and 35.518 ng for TRX per 0.1 billion EVs, compared to the amounts of target proteins expressed intracellularly, i.e., 0.667 ng for FGF1 and 0.047 ng for TRX per 0.1 billion EVs. 
     3. Identification of Effect of Growth Factor-Containing EVs on Cell Proliferation 
     The concentration of each target protein in the EVs isolated according to the method described in 2. above was measured, and then each target protein was sequentially diluted with PBS 10-fold each for 4 steps at a starting concentration of 20 μL. 20 μL of each diluent was added to a 96-well plate including an NIH3T3 cell line or HaCat cells at a density of 5,000 cells/well, followed by incubation at 37° C. for 48 hours. Subsequently, 10 μL of a cell counting kit-8 (Dojindo) solution was added to each well. After 2 hours, absorbance was measured at 450 nm. NIH3T3 cells were used for the cases of FGF1, FGF2, and IGF, and the HaCat cells were used for the cases of TGFa and EGF. 
       FIG. 4  illustrates an effect of growth factor-containing EVs isolated from yeast on cell proliferation. In  FIG. 4 , SC denotes Saccharomyces cerevisiae. 
     As a result, the target protein-containing EVs increased the number of cells in a dose-dependent manner. In  FIG. 4 ,  Pichia  EV-FGF1 and Hansenula EV-FGF1 were obtained by the same process as that used in the case of  S. cerevisiae,  except that Pichia pastoris or Hansenula polymorpha transformed with FGF1 was used. In  FIG. 4 , the horizontal axis denotes the concentration (w/v, ng/ml) of target protein in EVs in a medium. The vertical axis denotes a degree to which cells were proliferated in an EV-containing solution by comparison with a control (100%), wherein the degree was expressed as a percentage. 
     4. Identification of IL-22 Expression 
     The expression vector p426G-MF-IL-22 was constructed using IL-22 as a target protein in the same manner as described in 1. above, and as described in 2. above, the expression vector was transformed into the  S. cerevisiae  CEN.PK2-1. As a control, the same p426G-MF vector but not including IL-22 was used. 
     In particular, a Colo205 cell line was cultured in a 96-well plate in RPMI medium for 48 hours at 37° C., and then transformed with the p426G-MF-IL22 vector or the p426G-MF vector to purify EVs derived from yeast expressing or not expressing IL22. The EVs was suspended in PBS at a concentration of 0.5 mg/mL, and 20 μL of the EVs was added to each well of the 96-well plate, followed by further culturing for 6 hours at 37° C. Thereafter, proteins were extracted from the cell line to compare expression levels of IL-22 indirectly through the expression level of IL-10. IL-22 has the amino acid sequence of SEQ ID NO: 19. IL-22 is known to promote the production of IL-10. 
       FIG. 5  illustrates the production of the IL-10 protein identified from among proteins extracted from the Colo205 cell line treated with IL-22-containing EVs or IL-22-free EVs. As illustrated in  FIG. 5 , when the cells were cultured after being brought into contact with the IL-22-containing EVs, the production of the IL-10 protein was significantly increased compared to that in the IL-22-free EVs. In  FIG. 5 , lane 1 represents the degree of production of the IL-10 protein of the Colo205 cell line treated with the IL-22-free EVs, and lane 2 represents the degree of production of the IL-10 protein of the Colo205 cell line treated with the IL-22-containing EVs. 
     5. Fusion of Yeast-Derived EVs with Cells 
     EVs were isolated from an untransformed  S. cerevisiae  CEN.PK2-1 strain as described above. 1 ml of the isolated EVs (0.5 mg/ml PBS) was placed in a 5 μM 5-carboxyfluorescein N-hydroxysuccinimidyl ester (CFSE) solution at room temperature for 30 minutes. Subsequently, the remaining CFSE was removed from the solution by using a PD-10 desalting column (GE) to obtain CFSE-labeled EVs. An NIH3T3 cell line was cultured in 0.2 mL RPMI medium in each well of a 96-well plate for 48 hours at 37° C., and then 10 μL (red) or 20 μL (green) of the CFSE-labeled EVs in PBS was added to each well, followed by further culturing for 24 hours at 37° C. Thereafter, the cells were washed with PBS. The residual cells were allowed to pass through a flow cytometer and fluorescence therefor was measured. As a control, 0.5 μg/ml of BSA was labeled with CFSE and 20 μL of the resulting material was used. 
       FIG. 6  illustrates results of observing the degree of fusion between CFSE-labeled EVs and cells through cell flow analysis. In  FIG. 6 , negative control (left graph) represents cells brought into contact with the CFSE-labeled BSA, and experimental group (right graph) represents observation results of cells brought into contact with 10 μL (red) or 20 μL (green) of the CFSE-labeled EVs. As a result, as illustrated in the right graph of  FIG. 6 , cells were stained with CFSE, from which it was confirmed that the EVs were fused with the cells, resulting in introduction of components of the EVs into the cells. NIH3T3 cells are a standard fibroblast cell line. 
     6. Confirmation of Skin Toxicity of Yeast-Derived EVs 
     The toxicity of yeast-derived EVs to the skin was measured through toxicity experiments for artificial skin in accordance with the OECD guidelines. As artificial skin, Neoderm™-ED (manufactured by Taigo Science Co., Ltd.) was used. 
     EVs derived from  S. cerevisiae, Pichia pastoris,  or  Hansenula polymorpha  were isolated. The  S. cerevisiae -derived EVs were isolated as described in 2. above. The isolation of the  Pichia pastoris - or  Hansenula polymorpha -derived EVs was performed in the same manner as in 2. above, except that  Pichia pastoris  and  Hansenula polymorpha  were used for the respective cases. 
     30 μL of each of the isolated EVs, PBS as a negative control, and 5% SDS as a positive control were applied to the Neoderm™-ED artificial skin, followed by incubation for 15 minutes at 37° C. Subsequently, the artificial skin was washed with PBS, and then immersed in 2 ml of an assay medium (Taigo Science Co., Ltd.) in a 12-well plate, followed by further incubation for 42 hours at 37° C. 
     The incubated artificial skin was taken out and transferred to a 0.3% MTT solution (0.3 mg/ml), followed by incubation for 3 hours at 37° C. Thereafter, the artificial skin was taken out again, each tissue was separated using an 8 mm biopsy punch, added to 500 μl of 0.04N HCl-isopropanol, and then decolored for 4 hours. Absorbance at 570 nm was measured, and then compared with that of the controls to obtain viability (%). 
     As a result, a case in which the measured viability was a median between values of the positive and negative controls or greater was determined as non-toxic. The viability was calculated according to Equation below: 
       Viability=absorbance of test material/absorbance of negative control×100
 
       FIG. 7  illustrates results of measuring the toxicity of yeast-derived EVs to the skin. 
     In  FIG. 7, 1 : negative control (PBS), 2: positive control (5% SDS), 3:  S. cerevisiae derived EVs, 4: P. pastoris-derived EVs, 5:  H. polymorpha -derived EVs. 
     EXAMPLE 2 
     Lactic Acid Bacteria (LAB) Cell-Derived EVs 
     Recombinant lactic acid bacteria expressing target proteins were prepared and EVs were isolated from the lactic acid bacteria. Detailed procedures are as follows. As LAB cells,  Lactobacillus paracasei  LMT1-21 (KCTC13422BP),  Lactobacillus brevis  LMT1-46 (KCTC13423BP) and/or  Lactobacillus plantarum  LMT1-9 (KCTC13421BP) were used. 
     1. Construction of Gene Expression Vector 
     For a target gene, a nucleotide sequence having a codon optimized for LAB used was obtained from amino acid sequences of a protein using the codon optimization tool (http://sq.idtdna.com/CodonOpt), a sequence having recognition sequences of BamHI and XhoI restriction enzymes at opposite terminals thereof was devised, and DNA having this sequence was synthesized (Macrogen, Korea). The synthesized gene was digested with the BamHI and XhoI restriction enzymes. In addition, the parent vector pMT182-PR4 (SEQ ID NO: 20) was digested with the same restriction enzymes and purified using a gel purification kit and then dephosphorylated using alkaline phosphatase (AP). This parental vector includes a promoter PR4 to express the target protein and the signal peptide SP4 (SEQ ID NO: 21) to extracellulary secrete it. 
     1 μL of the prepared vector DNA, 3 μL of insert DNA, 0.5 μL of T4 DNA ligase (Takara, Japan), and 1 μL of a buffer solution were added to 5.5 μL of distilled water a total volume of 10 μL. The reaction solution was incubated at 16° C. for 12 hours to allow a ligation reaction, and the resulting ligated product was transformed into an  E. coli  Top10 strain according to a method (Sambrook et al., Molecular Cloning: A laboratory manual, 2nd ed.1989). The sequence of the plasmid obtained from each colony was analyzed and identified. The target proteins used were FGF1, FGF2, EGF, IGF, KGF, TGFa, TRX, and IL-22. These target proteins respectively have the amino acid sequences of SEQ ID NOS: 1, 2, 3, 4, 5, 6, 7, and 8. 
     2. LAB transformation 
     The obtained cloned DNA was transformed into three kinds of lactic acid bacteria. 
     Each strain was cultured in 50 mL of MRS until OD 600  reached 0.5, and then centrifuged at 7,000 rpm for 10 min at 4° C. and washed twice with 25 mL of ice-cold EPS (containing 1 mM K 2 HPO 4  KH 2 PO 4 , pH 7.4, 1 mM MgCl 2 , and 0.5 M sucrose). These cells were suspended in 1 mL of ice-cold EPS to prepare competent cells to be used for electroporation, and stored in a deep freezer at −80° C. 40 μL of the competent cells and 1 μg/μL of vector DNA were transferred to a cuvette and left on ice for 5 minutes. After pulsing at 25 μF, 8 kV/cm, and 400 ohms, 1 mL MRS liquid medium was added immediately and incubated at 37° C. for about 1 hour. The cells were plated on MRS medium containing 10 μg/ml of chloramphenicol and cultured at 37° C. for 49 hours to obtain transformed cells. 
     3. Isolation of EVs 
     Among the resulting transformed LAB strains, the KCTC13422BP strain was statically cultured in an MRS liquid medium at 37° C. for 16 hours, and then 2% (w/v) of the strain was inoculated again into the MRS liquid medium, followed by static culture for 16 hours. The obtained culture was centrifuged at 5,000×g for 15 minutes to obtain a supernatant from which LAB was removed, and then concentrated 20-fold by ultrafiltration using a 100 kDa molecular weight cut-off (MWCO) ultrafiltration membrane. The concentrate was ultracentrifuged at 150,000×g for 3 hours to obtain a sunken pellet, and the pellet was resuspended in PBS to obtain an EV solution. The size and number of the obtained EVs were measured using NanoSight NS300 (Malvern). The results thereof are illustrated in  FIG. 8 . 
       FIG. 8  illustrates the size and concentration distribution of EVs isolated from transformed LAB. In  FIG. 8 , the horizontal axis denotes a diameter, and the vertical axis denotes a concentration (particles/ml). In  FIG. 8 , the used LAB was a KCTC13422BP strain, and the target protein was FGF1. 
     As illustrated in  FIG. 8 , EVs were distributed such that 90% of particles were distributed at the particle sizes of 80 nm to 250 nm. 
     4. Confirmation of Presence of Target Protein In EVs 
     Western blotting was performed on the EV solution obtained in 3. above to confirm whether the target proteins were present in the EVs. The EVs were isolated from the KCTC13422BP strain (hereinafter, also referred to as LMT1-21) transformed with a vector obtained by cloning pMT182-PR4 with a gene encoding FGF1 or TRX. At this time, the gene used has a sequence fused or not fused with a signal peptide, i.e., an SP4 sequence. 
     Western blotting was performed as follows. A 4× loading buffer (thermo) and a 10× reducing agent (thermo) were added to 5 μL of the EV solution, and then electrophoresed on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel. Proteins of this gel were transferred to a nitrocellulose membrane, which was then blocked by incubation in Tris-buffered saline with Tween 20 (TBST) containing 5% skim milk as a blocking solution for 2 hours. After washing with TBST three times for 5 minutes, the membrane and primary antibodies were added to the blocking solution and incubated for 2 hours to induce antigen-antibody binding. After washing with TBST, secondary antibodies were added thereto. After standing for 1 hour, the amounts and positions of the target proteins were confirmed using an enhanced electrochemical (ECL) system. 
       FIG. 9  illustrates western blotting results of the EV solution. As illustrated in  FIG. 9 , FGF1 and TRX are expressed in EVs isolated from LMT1-21 transformed with a vector obtained by cloning pMT182-PR4 with FGF1 and TRX fused with a signal peptide, respectively, from which it is evident that these target proteins are present in EVs. 
       FIG. 10  illustrates western blotting results of EVs isolated from LMT1-21 transformed with a recombinant vector including a gene encoding FGF1 that was fused or not fused with a signal peptide gene, i.e., pMT182-PR4-FGF1 or pMT182-PR4-SP4-FGF1. In  FIG. 10 , lane 1 represents EVs when the FGF1 gene was expressed in the absence of a signal peptide, and lane 2 represents EVs when a gene encoding a fusion protein of a signal peptide and FGF1 was expressed. 
     5. Identification of Efficacy of EVs Containing Growth Factor Derived from LAB on Cell Proliferation 
     The EVs isolated from the 1 L LAB culture broth were suspended in 1 ml of PBS according to the method described in 3, above. An NIH3T3 cell line (or HaCat cells) in DMEM medium was seeded into each well of a 96-well plate at a density of 5,000 cells/well and cultured at 37° C. for 48 hours. Then, 20 μL of the solution including EVs expressing a growth factor or PBS as a control was added thereto. The cells were cultured under the same conditions for 48 hours, and then 10 μL of a cell counting kit-8 (Dojindo) solution was added to each well. After 2 hours, absorbance was measured at 450 nm. NIH3T3 cells were used for the cases of FGF1, FGF2, and IGF, and HaCat cells were used for the cases of KGF, TGFa, and EGF. 
       FIG. 11  illustrates an effect of growth factor-containing EVs isolated from LAB on cell proliferation. In  FIG. 11 , LAB denotes a lactic acid bacterium (KCTC13422BP strain). As a result, the target protein-containing EVs increased cell concentration in a dose-dependent manner. In  FIG. 11 , the horizontal axis denotes the concentration (w/v) of a target protein included in the EVs. The vertical axis denotes a degree of cell proliferation by the EV-containing solution used by comparison with a control, wherein the degree is expressed as a percentage. 
     6. Efficacy of Growth Factor-Containing EVs: Confirmation of IL-10 Expression 
     A vector expressing IL-22 was constructed according to 1. and 2. above, and this vector was transformed into LMT1-21. EVs were isolated from LMT1-21 transformed with the vector expressing IL-22 according to 3. above. To confirm whether the EVs promote IL-10 expression in the cells, the presence of IL-22 was indirectly assumed. 
     In particular, a Colo205 cell line was cultured in RPMI medium in a 96-well plate for 48 hours at 37° C., EVs derived from LAB expressing or not expressing IL-22 were isolated and suspended in PBS at a concentration of 0.5 mg/mL, and then 20 μL of each suspension was added to each well, followed by further culturing for 6 hours at 37° C. Subsequently, proteins were extracted from the cell line, i.e., by cell lysis to obtain a lysate, and among the proteins, expression levels of IL-10 were compared with each other. 
       FIG. 12  is a set of images showing western blotting results of proteins derived from cells that were brought into contact with LMT1-21-derived EVs. In  FIG. 12 , lane 1 represents PBS, lane 2 represents LMT1-21-derived EVs, and lane 3 represents EVs derived from LMT1-21 expressing IL-22. 
     7. Fusion of LAB-Derived EVs with Cells 
     EVs were isolated from an untransformed LAB strain (KCTC13422BP) as described above. 1 ml of the isolated EVs (0.5 mg/ml PBS) was placed in a 5 μM CFSE solution at room temperature for 30 minutes. Subsequently, the remaining CFSE was removed from the solution by using a PD-10 desalting column (GE) to obtain CFSE-labeled EVs. An NIH3T3 cell line was cultured in 0.2 mL RPMI medium in each well of a 96-well plate for 48 hours, and then 10 μL (red) or 20 μL (green) of the CFSE-labeled EVs in PBS was added to each well, followed by further culturing for 24 hours. Thereafter, the cells were washed with PBS. The residual cells were allowed to pass through a flow cytometer and fluorescence therefor was measured. As a control, 0.5 μg/ml of BSA was labeled with CFSE and 20 μl of the resulting material was used. 
       FIG. 13  illustrates results of observing the degree of fusion of CFSE-labeled EVs with cells through cell flow analysis. In  FIG. 13 , negative control (left graph) represents cells brought into contact with the CFSE-labeled BSA, and experimental group (right graph) represents observation results of cells brought into contact with 10 μL (red) or 20 μL (green) of the CFSE-labeled EVs. As a result, as illustrated in the right graph of  FIG. 13 , cells were stained with CFSE, from which it was confirmed that the EVs were fused with the cells, resulting in introduction of components of the EVs into the cells. NIH3T3 cells are a standard fibroblast cell line. 
     8. Confirmation of Skin Toxicity of LAB-Derived EVs 
     The toxicity of LAB-derived EVs to the skin was measured through toxicity experiments for artificial skin in accordance with the OECD guidelines. As artificial skin, Neoderm™-ED (manufactured by Taigo Science Co., Ltd.) was used. 
     EVs derived from LMT1-21, LMT1-9, or LMT1-46 were isolated. These EVs were isolated as described in 2. above. 30 μL of each of the isolated EVs, PBS as a negative control, and 5% SDS as a positive control were applied to the Neoderm™-ED artificial skin, followed by incubation for 15 minutes at 37° C. Subsequently, the artificial skin was washed with PBS, and then immersed in 2 ml of an assay medium (Taigo Science Co., Ltd.) in a 12-well plate, followed by further incubation for 42 hours at 37° C. 
     The incubated artificial skin was taken out and transferred to a 0.3% MTT solution (0.3 mg/ml), followed by incubation for 3 hours. Thereafter, the artificial skin was taken out again, each tissue was separated using an 8 mm biopsy punch, added to 500 μl of 0.04N HCl-isopropanol, and then decolored for 4 hours. Absorbance at 570 nm was measured, and then compared with that of the controls to obtain viability (%). As a result, a case in which the measured viability was a median between values of the positive and negative controls or greater was determined as non-toxic. The viability was calculated according to Equation below: 
       Viability=absorbance of test material/absorbance of negative control×100
 
       FIG. 14  illustrates results of measuring toxicity of LAB-derived EVs to the skin. In  FIG. 14 , 1: negative control (PBS), 2: positive control (5% SDS), 3: LMT1-46-derived EVs, 4: LMT1-9-derived EVs, and 5: LMT1-21-derived EVs. 
     EXAMPLE 3 
     Comparing the Cell Proliferation Effect of Growth Factor-Containing EVs with that of Naked Growth Factors 
     1. Preparation of Growth Factor-Containing EVs 
     Growth factor-containing EVs were isolated from  Pichia pastoris  transformed with p416G-MF-EGF, p416G-MF-FGF1 and p416G-MF-FGF2, respectively as the same manner with item 3 in Example 1. Each of those was suspended in PBS to adjust the concentration of EGF to 10 ug/ml and the concentration of FGF1 or FGF2 to 1 ug/ml. As control, naked EGF, FGF1, and FGF2 proteins were purchased from AbCam, and suspended in PBS to the same concentrations above. 
     2. Comparing the Effect of Growth Factor-Containing EVs with that of Naked Growth Factors on Cell Proliferation 
     Artificial skin, Neoderm™-ED was purchased from Taigo Science Co., Ltd. The artificial skins were washed with PBS, and then added to 2 mL PBS, 2 mL EV-growth factor-containing solutions as prepared above and 2 mL of control solution containing naked EGF, FGF1, or FGF2 protein as prepared above in wells of a 12-well plate, followed by further incubation for 24 hours at 37° C. After washing with PBS three times, artificial skins were fixed in 4% paraformaldehyde solution (Sigma, USA) for 18 hours at 37° C. and frozen-sectioned using Leica Biosystems. Immunohistochemistry (IHC) was performed using anti-Ki-67 antibody (AbCam) for EGF-EV and control protein, and anti-collagen antibody (AbCam) for FGF1-EV, FGF2-EV and control proteins, followed by addition of DAB (3,3′Diaminobenzidine). The results were photographed under a microscope. In general, abundance of Ki-67 or collagen is observed with brown color. Ki-67 is known as a biomarker of epidermal cell proliferation. 
     As seen in  FIG. 15 , better epidermal cell proliferation was observed with EGF-EV treatment compared with the PBS and the control protein treatment (Row A). Also, better collagen synthesis was observed when using FGF1-EV and FGF2-EV compared with the using PBS or the control proteins (Row B and C). According to these results, growth factors which were contained in EVs were more effective on cell proliferation compared with naked growth factors regardless of growth factor types, and among them, FGF2-EV was most effective compared with any other growth factors which were contained in EVs or not contained in EVs. 
     EXAMPLE 4 
     Comparing the Growth Factor stability 
     1. EGF-EV Stability compared with naked EGF Stability 
       Pichia pastoris  derived EGF-EV and the control protein, i.e., EGF protein which is not contained in EV were prepared as the same manner as described in item 2 in Example 1. Briefly, the EGF-EVs or the EGF protein was suspended in 1 ml of PBS to concentration of to be 10 ug/ml. and then incubated at 40° C. for 8 weeks. Biweekly the samples were aliquoted and diluted using PBS to the concentration of 100 ng/ml for cell proliferation activity assay. 
     HaCat cells in DMEM medium was seeded into each well of a 96-well plate at a density of 5,000 cells/well and cultured at 37° C. for 48 hours. Then, 20 μL of the above each sample of EGF-EV, control protein, and PBS was added thereto. The cells were cultured under the same conditions for 48 hours, and then 10 μL of a cell counting kit-8 (Dojindo) solution was added to each well. After 2 hours, absorbance was measured at 450 nm. 
     As seen in  FIG. 16 , EGFs which contained in EVs were more stable then naked EGFs. 
     2. FGF2-EV Stability Compared with Naked FGF2 Stability 
       Pichia pastoris  derived FGF2-EV and the control protein, i.e., FGF2 protein which is not contained in EV were prepared as the same manner as described in item 2 in Example 1. Briefly, the FGF2-EVs or the FGF2 protein was suspended in 1 ml of PBS to concentration of to be 10 ug/ml. and then incubated at room temperature for 4 weeks. Each sample was aliquoted and diluted using PBS on regular basis to the concentration of 100 ng/ml for cell proliferation activity assay. 
     NIH3T3 cells in DMEM medium was seeded into each well of a 96-well plate at a density of 5,000 cells/well and cultured at 37° C. for 48 hours. Then, 20 μL of the above each sample of FGF2-EV, control protein, and PBS was added. The cells were cultured under the same conditions for 48 hours, and then 10 μL of a cell counting kit-8 (Dojindo) solution was added to each well. After 2 hours, absorbance was measured at 450 nm. 
     As seen in  FIG. 17 , FGF2s which contained in EVs were more stable then naked FGF2s. 
     INDUSTRIAL APPLICABILITY 
     A recombinant microorganism according to one embodiment may be used to efficiently isolate EVs or target proteins from the EVs. 
     According to another embodiment, a composition for delivering the EVs and target proteins to a subject may be used to efficiently deliver the target proteins to a subject. 
     According to another embodiment, a method of treating a disease of a subject may be used to efficiently treat the disease. 
     According to another embodiment, a method of applying a cosmetic to a subject may be used to efficiently apply a cosmetic to a subject. 
     According to another embodiment, a method of producing EVs may be used to efficiently produce EVs.