Mesenchymal stem cell particles

Abstract

We describe a particle secreted by a mesenchymal stem cell and comprising at least one biological property of a mesenchymal stem cell. The biological property may comprise a biological activity of a mesenchymal stem cell conditioned medium (MSC-CM) such as cardioprotection or reduction of infarct size. The particle may comprise a vesicle or an exosome.

1 . An exosome isolated from a mesenchymal stem cell and having a size of between 50 nm and 100 nm as determined by electron microscopy, the exosome comprising at least one biological property of a mesenchymal stem cell. 
     
     
         2 . The exosome of  claim 1 , which reduces infarct size when assayed in a mouse or pig model of myocardial ischemia and reperfusion injury, or which reduces oxidative stress when assayed in an in vitro assay of hydrogen peroxide (H 2 O 2 )-induced cell death. 
     
     
         3 . The exosome of  claim 1 , in which the exosome comprises at least 70% of proteins in an mesenchymal stem cell conditioned medium (MSC-CM) listed in Table D1 or E2 or are gene products of the genes listed in Table D2, or in which the exosome comprises one or more miRNAs listed in Table E3. 
     
     
         4 . The exosome of  claim 1 , in which the exosome comprises: (a) a complex of molecular weight >100 kDa; (b) a complex of molecular weight >300 kDa; or (c) a complex of molecular weight >1000 kDa. 
     
     
         5 . The exosome of  claim 1 , in which the exosome has a size of between 2 nm and 200 nm, as determined by filtration against a 0.2 μM filter and concentration against a membrane with a molecular weight cut-off of 10 kDa, or a hydrodynamic radius of below 100 nm as determined by laser diffraction or dynamic light scattering. 
     
     
         6 . The exosome of  claim 1 , in which the exosome comprises a lipid selected from the group consisting of: phospholipid, phosphatidyl serine, phosphatidyl inositol, phosphatidyl choline, shingomyelin, ceramides, glycolipid, cerebroside, steroids, and cholesterol. 
     
     
         7 . The exosome of  claim 4 , in which the exosome comprises a lipid raft, or in which the exosome is insoluble in non-ionic detergent, or in which the exosome is such that proteins of the molecular weights specified in  claim 4  substantially remain in the complexes of the molecular weights specified in  claim 4  when the exosome is treated with a non-ionic detergent, or in which the exosome is sensitive to cyclodextrin, such that treatment with cyclodextrin causes substantial dissolution of the complexes specified in  claim 4 . 
     
     
         8 . The exosome of  claim 1 , in which the exosome comprises ribonucleic acid (RNA), or in which the exosome comprises a surface antigen selected from the group consisting of: CD9, CD109 and thy-1. 
     
     
         9 . A method of producing an exosome of  claim 1 , the method comprising isolating the exosome from a mesenchymal stem cell conditioned medium (MSC-CM), the method optionally comprising separating the exosome from other components based on molecular weight, size, shape, composition or biological activity. 
     
     
         10 . A method of producing an exosome of  claim 1 , the method comprising:
 (a) obtaining a mesenchymal stem cell conditioned medium (MSC-CM);   (b) concentrating the mesenchymal stem cell conditioned medium;   (c) subjecting the concentrated mesenchymal stem cell conditioned medium to size exclusion chromatography; and   (d) selecting UV absorbent fractions at 220 nm, that exhibit dynamic light scattering;   in which step (d) comprises collecting fractions which elute with a retention time of 11-13 minutes.   
     
     
         11 . A pharmaceutical composition comprising an exosome of  claim 1  together with a pharmaceutically acceptable excipient, diluent or carrier. 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . A delivery system for delivering an exosome according to  claim 1 , comprising a source of exosome together with a dispenser operable to deliver the exosome to a target. 
     
     
         17 . (canceled) 
     
     
         18 . The exosome of  claim 1 , wherein said biological activity comprises a biological activity of a mesenchymal stem cell conditioned medium (MSC-CM). 
     
     
         19 . The exosome of  claim 1 , wherein said biological activity comprises cardioprotection, reduction of oxidative stress or reduction in cardiac infarct size. 
     
     
         20 . The exosome of  claim 5 , which has a size between 50 nm and 150 nm. 
     
     
         21 . The exosome of  claim 5 , which has a hydrodynamic radius between about 30 nm and about 70 nm. 
     
     
         22 . The exosome of  claim 6 , which has a cholesterol-phospholipid ratio greater than 0.3-0.4 (mol/mol). 
     
     
         23 . A method for the treatment of a disease treatable by regenerative therapy in an individual in need thereof, the method comprising administering a pharmaceutical composition of  claim 11  to said individual, whereby said disease is treated. 
     
     
         24 . The method of  claim 23 , wherein said disease is selected from the group consisting of: cardiac failure, bone marrow disease, skin disease, burns and degenerative diseases such as diabetes, Alzheimer's disease, Parkinson's disease, cancer, myocardial infarction, a cutaneous wound, a dermatologic disorder, a dermatological lesion, dermatitis, psoriasis, condyloma, verruca, hemangioma, keloid, skin cancer, atopic dermatitis, Behcet disease, chronic granulomatous disease, cutaneous T cell lymphoma, ulceration, a pathological condition characterised by initial injury inducing inflammation and immune dysregulation leading to chronic tissue remodeling including fibrosis and loss of function, renal ischemic injury, cystic fibrosis, sinusitis and rhinitis or an orthopedic disease. 
     
     
         25 . The method of  claim 23 , wherein said disease comprises heart disease. 
     
     
         26 . A method of delivering an exosome of  claim 1  to a target cell or tissue, the method comprising providing an exosome delivery system comprising a source of exosome together with a dispenser operable to deliver the exosome to a target, and delivery of said exosome to said target using said delivery system.