MRI tracking of human Wharton’s jelly stem cells seeded onto acellular dermal matrix labeled with superparamagnetic iron oxide nanoparticles in burn wounds

Background:In vivo cell tracking after transplantation in regenerative medicine remains an unmet challenge and limits current understanding of the wound healing mechanism through cell-based therapies.This study investigated tracking of human Wharton’s jelly stem cells(hWJSCs)seeded onto an acellular dermal matrix(ADM)and labeled with superparamagnetic iron oxide nanoparti-cles(SPIONs)by magnetic resonance imaging(MRI)in burn injury.Method:The hWJSCs were characterized and assessed for growth kinetics.A total of 30 rats were enrolled in three equal groups.Group 1 underwent scald burn injury left without treatment,the group 2 was treated by an ADM that was prepared from cosmetic surgery skin samples and the group 3 received hWJSCs labeled with SPIONs seeded onto an ADM.Tensile strength was evaluated before and after interventions,real time PCR assessed apoptosis,and Prussian blue staining,scanning electron microscopy(SEM)and MRI were used for the tracking of labeled cells.Results:The hWJSCs exhibited mesenchymal stem cell properties.Population doubling time was 40.1 hours.SPIONs did not show any toxic effect.The hWJSCs seeded onto an ADM decreased Bax and increased Bcl-2 gene expression.Internalization of SPIONs within hWJSCs was confirmed by Prussian blue staining,SEM and MRI until day 21.There was a significant difference between the Young’s moduli of normal skin and the group receiving hWJSCs seeded onto an ADM.Histological observations and SEM imaging confirmed that MRI is an accurate method to track SPION-labeled hWJSCs in vivo.Conclusions:This study showed that SPION labeling coupled with MRI can be used to further understand the fate of stem cells after transplantation in a burn model.

Functional and structural characterization of Ebola virus glycoprotein （1976-2015） -- An in silico study

Ebola virus （EBOV） is the causative agent of a severe hemorrhagic fever disease associ- ated with high mortality rates in humans. This virus has five strains of which Zaire Ebola virus （ZEBOV） is the first and most important strain. It can be transmitted through contact with contaminated surfaces and objects. The genome of EBOV codes one non- structural and seven structural proteins consisting of two forms of glycoprotein （GP）： soluble glycoprotein （sGP） and GP （spike）. In this paper, we attempted to characterize and predict physicochemical properties, B-cell epitopes, mutation sites, phosphorylation sites, glycosylation sites, and different protein structures of EBOV GP to provide com- prehensive data about changes of this GP during a 40-years course （1976-2015）. GP sequences were obtained from NCBI gene bank from 1976-2015. Expasy＇sProtParam, PROTSCALE, immuneepitope, Bepipred, BcePred, ABCpred, VaxiJen, DISPHOS, Net- Phos, and numerous programs were used to predict and analyze all sequences. More variety of mutations were found in 2015 sequences and mutations were related to huge changes in B-cell epitopes, phosphorylation and glycosylation sites. In addition, our results determined different sites of disulfide bonds and an important mutation related to IgE epitope as well as four potent B-cell epitopes （380-387, 318-338, 405-438 and 434-475）. In this study, we suggested the effect of mutations on GP properties, six posi- tions for disulfide bonds and four phosphorylation sites for protein kinase C enzyme. Selected sequences were shown different sites for O-link and N-link glycosyl^tion. A mutation that changed GP to an allergen protein and has a significant role in vaccine designing as well as four potent B-cell epitopes in GP protein were found.