Cell Therapy for Diabetic Neuropathy Using Adult Stem or Progenitor Cells

Diabetic neuropathy (DN) is the most common and disabling complication of diabetes that may lead to foot ulcers and limb amputations. Despite widespread awareness of DN, the only effective treatments are glucose control and pain management. A growing body of evidence suggests that DN is characterized by reduction of vascularity in peripheral nerves and deficiency in neurotrophic and angiogenic factors. Previous studies have tried to introduce neurotrophic or angiogenic factors in the form of protein or gene for therapy, but the effect was not significant. Recent studies have shown that bone marrow (BM)-derived stem or progenitor cells have favorable effects on the repair of cardiovascular diseases. Since these BM-derived stem or progenitor cells contain various angiogenic and neurotrophic factors, these cells have been attempted for treating experimental DN, and turned out to be effective for reversing various manifestations of experimental DN. These evidences suggest that cell therapy, affecting both vascular and neural components, can represent a novel therapeutic option for treatment of clinical DN.

Role of N-terminal Hydrophilic Amino Acids in Molecular Translocation of CTLA-4 to Cell Surface

BACKGROUND: This study was aimed to differentiate two forms of CTLA-4 (CD152) in activated peripheral blood lymphocyte and clarify the mechanism how cytoplasmic form of this molecule is targeted to cell surface. METHODS: For this purpose we generated 2 different anti-human CD152 peptide antibodies and 5 different N'-terminal deletion mutant CTLA4Ig fusion proteins and carried out a series of Western blot and ELISA analyses. Antipeptide antibodies made in this study were anti-CTLA4pB and anti- CTLA4pN. The former recognized a region on extracellular single V-like domain and the latter recognized N'-terminal sequence of leader domain of human CD152. RESULTS: In Western blot, the former antibody recognized recombinant human CTLA4Ig fusion protein as an antigen. And this recognition was completely blocked by preincubating antipeptide antibody with the peptide used for the antibody generation at the peptide concentration of 200 ug/ml. These antibodies were recognized human CD152 as a cytoplasmic sequestered- and a membrane bound- forms in phytohemagglutinin (PHA)- stimulated peripheral blood lymphocyte (PBL). These two forms of CD152 were further differentiated by using anti-CTLA4pN and anti-CTLA4pB antibodies such that former recognized cytosolic form only while latter recognized both cytoplasmic- and membrane- forms of this molecule. Furthermore, in a transfection expression study of 5 different N'-terminal deletion mutant CTLA4Ig, mutated proteins were secreted out from transfected cell surface only when more than 6 amino acids from N'-terminal were deleted. CONCLUSION: Our results implies that cytosolic form of CTLA-4 has leader sequence while membrane form of this molecule does not. And also suggested is that at least N'-terminal 6 amino acid residues of human CTLA-4 are required for regulation of targeting this molecule from cytosolic- to membrane- area of activated human peripheral blood T lymphocyte.