Identification of an antigenic domain near the C terminus of human granulocyte-macrophage colony-stimulating factor and its spatial localization.

The goal of this study was to map an epitope on the human granulocyte-macrophage colony-stimulating factor (hGM-CSF) at its C terminus, a region whose integrity is fundamental in maintaining the normal function of this molecule. Residues including the fourth alpha-helix (D, 103-116) were analyzed for their role in the interaction with antibodies (Abs) raised against the protein. Five peptides homologous to different segments of the C terminus of hGM-CSF were synthesized. Peptide-(102-121) included the same residues of the alpha-helix D and the next five amino acids toward the C terminus; peptide-[E108A]-(102-121) introduced the mutation E108A in order to verify the role of acidic residues; peptide-[C96A](93-110) encompassed the beta-sheet 2 and half of the alpha-helix D; peptide-[C121A]-(110-127) included the second half of the alpha-helix D and the C terminus of hGMCSF; peptide-(13-31)-Gly-Pro-Gly-(103-116) included both the alpha-helices A and D connected by the tripeptide Gly-Pro-Gly, which allows the original antiparallel orientation of the two alpha-helices to be maintained. Both anti-protein and anti-peptide-(102-121) antibodies, capable of neutralizing the stimulatory activity of hGMCSF in the bone marrow colony-forming assays, recognized a specific epitope in the C terminus of hGM-CSF. Molecular modeling estimated the surface accessibility of hGM-CSF and the stability of the synthetic peptides in aqueous solution. Altogether, our results showed that the immunogenic region includes part of the alpha-helix D and the residues 116-120, which are external to this helix and particularly exposed on the protein surface, confirming the feasible participation of this region in antibody binding

Transplanted human adipose tissue-derived stem cells engraft and induce regeneration in mice olfactory neuroepithelium in response to dichlobenil subministration

We used immunodeficient mice, whose dorsomedial olfactory region was permanently damaged by dichlobenil inoculation, to test the neuroregenerative properties of transplanted human adipose tissue-derived stem cells after 30 and 60 days. Analysis of polymerase chain reaction bands revealed that stem cells preferentially engrafted in the lesioned olfactory epithelium compared with undamaged mucosa of untreated transplanted mice. Although basal cell proliferation in untransplanted lesioned mice did not give rise to neuronal cells in the olfactory mucosa, we observed clusters of differentiating olfactory cells in transplanted mice. After 30 days, and even more at 60 days, epithelial thickness was partially recovered to normal values, as also the immunohistochemical properties. Functional reactivity to odorant stimulation was also confirmed through electroolfactogram recording in the dorsomedial epithelium. Furthermore, we demonstrated that engrafted stem cells fused with mouse cells in the olfactory organ, even if heterokaryons detected were too rare to hypothesize they directly repopulated the lesioned epithelium. The data reported prove that the migrating transplanted stem cells were able to induce a neuroregenerative process in a specific lesioned sensory area, enforcing the perspective that they could become an available tool for stem cell therapy. \ua9 The Author 2014. Published by Oxford University Press. All rights reserved

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Abstract. A 3D culture system was used to investigate the behaviour of mesothelial cells present in the wall of human processus vaginalis peritonei. Small tissue fragments placed on collagen sponges were cultured for 7, 14 and 21 days in medium supplemented with 10% FBS, and analysed for the expression and distribution of cytokeratins (CKAE1-AE3, CK19), p63, Ki-67, vimentin, CD34, and HBME-1. Before culture, flat mesothelial cells displayed immunoreactivity for cytokeratins, vimentin and HBME-1, while p63 and CD34 were negative. Mesenchymal cells within the stroma were vimentin-positive and endothelial cells of small vessels displayed positive staining for CD34. Cytokeratins, p63 and HBME-1 were negative in all stromal cells. In cultured fragments, flat mesothelial cells positive for vimentin, cytokeratins and HBME-1 proliferated, lining the fragment surface and migrating into the sponge. Capillaries showed morphological alterations; however, their immunoreactivity was comparable with the stroma prior to culture. Cells that had migrated into the sponge and displayed characteristics of mesothelial progenitors, predominantly spindleshaped and stellate, showed heterogeneous expression of markers especially in late phases of cultivation. These cells were constantly positive for vimentin, a small fraction was cytokeratin-positive and a few displayed HBME-1 immunoreactivity. CD34 was found in cells forming small cavities into the matrix, resembling newly formed blood vessels. Cells that had migrated into the sponge could be isolated and expanded in coculture with feeder NIH.3T3 fibroblasts. This system is suitable for studying growth and behaviour of mesothelial cells within their natural environment, providing a good method for isolation and expansion of their progenitor cells

Human mesenchymal stromal cell therapy for damaged cochlea repair in nod-scid mice deafened with kanamycin

BACKGROUND: Kanamycin, mainly used in the treatment of drug-resistant-tuberculosis, is known to cause irreversible hearing loss. Using the xeno-transplant model, we compared both in vitro and in vivo characteristics of human mesenchymal stromal cells (MSCs) derived from adult tissues, bone marrow (BM-MSCs) and adipose tissue (ADSCs). These tissues were selected for their availability, in vitro multipotency and regenerative potential in vivo in kanamycin-deafened nod-scid mice. METHODS: MSCs were isolated from informed donors and expanded ex vivo. We evaluated their proliferation capacity in vitro using the hexosaminidase assay, the phenotypic profile using flow-cytometry of a panel of surface antigens, the osteogenic potential using alkaline phosphatase activity and the adipogenic potential using oil-red-O staining. MSCs were intravenously injected in deafened mice and cochleae, liver, spleen and kidney were sampled 7 and 30 days after transplantation. The dissected organs were analyzed using lectin histochemistry, immunohistochemistry, polymerase chain reaction (PCR) and dual color fluorescence in situ hybridization (DC-FISH). RESULTS: MSCs showed similar in vitro characteristics, but ADSCs appeared to be more efficient after prolonged expansion. Both cell types engrafted in the cochlea of damaged mice, inducing regeneration of the damaged sensory structures. Several hybrid cells were detected in engrafted tissues. DISCUSSION: BM-MSCs and ADSCs showed in vitro characteristics suitable for tissue regeneration and fused with resident cells in engrafted tissues. The data suggest that paracrine effect is the prevalent mechanism inducing tissue recovery. Overall, BM-MSCs and ADSCs appear to be valuable tools in regenerative medicine for hearing loss recovery