title: Extensive fusion of haematopoietic cells with Purkinje neurons in response to chronic inflammation.
abstract: Transplanted bone marrow-derived cells (BMDCs) have been reported to fuse with cells of diverse tissues, but the extremely low frequency of fusion has led to the view that such events are biologically insignificant. Nonetheless, in mice with a lethal recessive liver disease (tyrosinaemia), transplantation of wild-type BMDCs restored liver function by cell fusion and prevented death, indicating that cell fusion can have beneficial effects. Here we report that chronic inflammation resulting from severe dermatitis or autoimmune encephalitis leads to robust fusion of BMDCs with Purkinje neurons and formation of hundreds of binucleate heterokaryons per cerebellum, a 10-100-fold higher frequency than previously reported. Single haematopoietic stem-cell transplants showed that the fusogenic cell is from the haematopoietic lineage and parabiosis experiments revealed that fusion can occur without irradiation. Transplantation of rat bone marrow into mice led to activation of dormant rat Purkinje neuron-specific genes in BMDC nuclei after fusion with mouse Purkinje neurons, consistent with nuclear reprogramming. The precise neurological role of these heterokaryons awaits elucidation, but their frequency in brain after inflammation is clearly much higher than previously appreciated.
authors.affiliation: Baxter Laboratory in Genetic Pharmacology, Stanford University School of Medicine, Stanford, CA 94305-5175, USA. clas.johansson@ki.se
authors.forename: Clas B
authors.initials: CB
authors.lastname: Johansson
authors.forename: Sawsan
authors.initials: S
authors.lastname: Youssef
authors.forename: Kassie
authors.initials: K
authors.lastname: Koleckar
authors.forename: Colin
authors.initials: C
authors.lastname: Holbrook
authors.forename: Regis
authors.initials: R
authors.lastname: Doyonnas
authors.forename: Stephane Y
authors.initials: SY
authors.lastname: Corbel
authors.forename: Lawrence
authors.initials: L
authors.lastname: Steinman
authors.forename: Fabio M V
authors.initials: FM
authors.lastname: Rossi
authors.forename: Helen M
authors.initials: HM
authors.lastname: Blau
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology*; D002459:Cell Fusion; D003872:Dermatitis / Q000276:immunology* / Q000473:pathology; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000276:immunology / Q000473:pathology; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000502:physiology*; D007249:Inflammation / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000276:immunology; D045164:Mesenchymal Stem Cell Transplantation; D051379:Mice; D008810:Mice, Inbred C57BL; D011689:Purkinje Cells / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018183:Transplantation Chimera
chemical_list: D008070:Lipopolysaccharides; D049452:Green Fluorescent Proteins