title: Inducing Heat Shock Proteins Enhances the Stemness of Frozen-Thawed Adipose Tissue-Derived Stem Cells.
abstract: Extensive research has been performed to determine the effect of freezing protocol and cryopreservation agents on the viability of adipose tissue-derived stromal/stem cells (ASCs) as well as other cells. Unfortunately, the conclusion one may draw after decades of research utilizing fundamentally similar cryopreservation techniques is that a barrier exists, which precludes full recovery. We hypothesize that agents capable of inducing a subset of heat shock proteins (HSPs) and chaperones will reduce the intrinsic barriers to the post-thaw recovery of ASCs. ASCs were exposed to 43°C for 1 h to upregulate HSPs, and the temporal HSP expression profile postheat shock was determined by performing quantitative polymerase chain reaction (PCR) and western blotting assays. The expression levels of HSP70 and HSP32 were found to be maximum at 3 h after the heat shock, whereas HSP90 and HSP27 remain unchanged. The heat shocked ASCs cryopreserved during maximal HSPs expression exhibited increased post-thaw viability than the nonheat shocked samples. Histochemical staining and quantitative reverse transcription-PCR indicated that the ASC differentiation potential was retained. Thus, suggesting that the upregulation of HSPs before a freezing insult is beneficial to ASCs and a potential alternative to the use of harmful cryoprotective agents.
authors.affiliation: 1 Bioengineering Laboratory, Department of Mechanical Engineering, Louisiana State University , Baton Rouge, Louisiana.
authors.forename: Shahensha
authors.initials: S
authors.lastname: Shaik
authors.affiliation: 2 Department of Biomedical Engineering, Pennsylvania State University , University Park, Pennsylvania.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hayes
authors.affiliation: 3 La Cell LLC and Center for Stem Cell Research and Regenerative Medicine and Departments of Medicine, Structural and Cellular Biology, and Surgery, Tulane University School of Medicine , New Orleans, Louisiana.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Gimble
authors.affiliation: 1 Bioengineering Laboratory, Department of Mechanical Engineering, Louisiana State University , Baton Rouge, Louisiana.
authors.forename: Ram
authors.initials: R
authors.lastname: Devireddy
mesh_terms: D000273:Adipose Tissue / Q000166:cytology*; D053687:Adult Stem Cells / Q000166:cytology* / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D015925:Cryopreservation / Q000379:methods*; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans
chemical_list: D006360:Heat-Shock Proteins
keywords: adipogenesis; adipose tissue-derived stem cells; cryopreservation; fluorescence-activated cell sorting; heat shock proteins; osteogenesis