title: TAT-mediated transduction of MafA protein in utero results in enhanced pancreatic insulin expression and changes in islet morphology.
abstract: Alongside Pdx1 and Beta2/NeuroD, the transcription factor MafA has been shown to be instrumental in the maintenance of the beta cell phenotype. Indeed, a combination of MafA, Pdx1 and Ngn3 (an upstream regulator of Beta2/NeuroD) was recently reported to lead to the effective reprogramming of acinar cells into insulin-producing beta cells. These experiments set the stage for the development of new strategies to address the impairment of glycemic control in diabetic patients. However, the clinical applicability of reprogramming in this context is deemed to be poor due to the need to use viral vehicles for the delivery of the above factors. Here we describe a recombinant transducible version of the MafA protein (TAT-MafA) that penetrates across cell membranes with an efficiency of 100% and binds to the insulin promoter in vitro. When injected in utero into living mouse embryos, TAT-MafA significantly up-regulates target genes and induces enhanced insulin production as well as cytoarchitectural changes consistent with faster islet maturation. As the latest addition to our armamentarium of transducible proteins (which already includes Pdx1 and Ngn3), the purification and characterization of a functional TAT-MafA protein opens the door to prospective therapeutic uses that circumvent the use of viral delivery. To our knowledge, this is also the first report on the use of protein transduction in utero.
authors.affiliation: Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America.
authors.forename: Nancy
authors.initials: N
authors.lastname: Vargas
authors.forename: Silvia
authors.initials: S
authors.lastname: Álvarez-Cubela
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Giraldo
authors.forename: Margarita
authors.initials: M
authors.lastname: Nieto
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Fort
authors.forename: Sirlene
authors.initials: S
authors.lastname: Cechin
authors.forename: Enrique
authors.initials: E
authors.lastname: García
authors.forename: Pedro
authors.initials: P
authors.lastname: Espino-Grosso
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Fraker
authors.forename: Camillo
authors.initials: C
authors.lastname: Ricordi
authors.forename: Luca
authors.initials: L
authors.lastname: Inverardi
authors.forename: Ricardo L
authors.initials: RL
authors.lastname: Pastori
authors.forename: Juan
authors.initials: J
authors.lastname: Domínguez-Bendala
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D005260:Female; D015870:Gene Expression; D015696:Gene Products, tat / Q000235:genetics / Q000378:metabolism; D007328:Insulin / Q000235:genetics / Q000378:metabolism*; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D051473:Maf Transcription Factors, Large / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010179:Pancreas / Q000196:embryology / Q000378:metabolism*; D011247:Pregnancy; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014599:Uterus / Q000378:metabolism*
chemical_list: D015696:Gene Products, tat; D007328:Insulin; D051473:Maf Transcription Factors, Large; C485160:Mafa protein, mouse; D011993:Recombinant Fusion Proteins