In the subventricular zone of the adult mammalian forebrain, neural stem cells (NSCs) reside and proliferate to generate young neurons. We screened factors that promoted the proliferation of NSCs in vitro by a recently developed proteomics technique, the ProteinChip system. In this screen, we identified a soluble carbohydrate-binding protein, Galectin-1, as a candidate. We show herein that Galectin-1 is expressed in a subset of slowly dividing subventricular zone astrocytes, which includes the NSCs. Based on results from intraventricular infusion experiments and phenotypic analyses of knockout mice, we demonstrate that Galectin-1 is an endogenous factor that promotes the proliferation of NSCs in the adult brain.lectin ͉ mobilization ͉ stem cell niche

The ribonucleoprotein enzyme telomerase synthesizes telomeric DNA onto chromosome ends. Telomere length is maintained, by the presence of telomerase activity, in the vast majority of primary tumours and stem cells, suggesting that telomere maintenance is essential for cellular immortalization. Recently, the telomerase RNA component in human and mouse (TERC and Terc, respectively), a telomerase-associated protein TEP1/TLP1 (refs 6,7) and the human catalytic subunit protein TERT (refs 8,9) have been identified. To examine the role of telomerase in telomere maintenance and cellular viability, we established Terc-deficient embryonic stem (ES) cells. It is known that telomerase activity is absent in cells from Terc-knockout mice. Although the study showed that telomere shortening was observed in the Terc-deficient cells from first to six generation animals, whether telomerase-dependent telomere maintenance was essential for cellular viability remained to be elucidated. To address this issue, we examined Terc-deficient ES cells under long-term culture conditions. Accompanying the continual telomere shortening, the growth rate of Terc-deficient ES cells was gradually reduced after more than 300 divisions. An impaired growth rate was maintained to approximately 450 divisions, and then cell growth virtually stopped. These data clearly show that telomerase-dependent telomere maintenance is critical for the growth of mammalian cells.

To screen for glycoproteins showing aberrant sialylation patterns in sera of cancer patients and apply such information for biomarker identification, we performed SELDI-TOF MS analysis coupled with lectin-coupled ProteinChip arrays (Jacalin or SNA) using sera obtained from lung cancer patients and control individuals. Our approach consisted of three processes (i) removal of 14 abundant proteins in serum, (ii) enrichment of glycoproteins with lectin-coupled ProteinChip arrays, and (iii) SELDI-TOF MS analysis with acidic glycoprotein-compatible matrix. We identified 41 protein peaks showing significant differences (p<0.05) in the peak levels between the cancer and control groups using the Jacalin- and SNA-ProteinChips. Among them, we identified loss of Neu5Ac (alpha2,6) Gal/GalNAc structure in apolipoprotein C-III (apoC-III) in cancer patients through subsequent MALDI-QIT-TOF MS/MS. Furthermore, subsequent validation experiments using an additional set of 60 lung adenocarcinoma patients and 30 normal controls demonstrated that there is a higher frequency of serum apoC-III with loss of alpha2,6-linkage Neu5Ac residues in lung cancer patients compared to controls. Our results have demonstrated that lectin-coupled ProteinChip technology allows the high-throughput and specific recognition of cancer-associated aberrant glycosylations, and implied a possibility of its applicability to studies on other diseases.

Summary Dysregulation of apoptosis through the Fas–Fas ligand pathway is associated with the onset of autoimmune disease. Since autoantibodies directed against unknown antigens are present in the sera of these patients, sera samples were examined for the presence of autoantibodies directed against the Fas molecule. Using Western blotting and a ProteinChip analysis, autoantibodies against Fas were detected in patients with silicosis, systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), and weakly detected in healthy individuals. Using epitope mapping employing 12‐amino‐acid polypeptides with the SPOTs system, a minimum of four epitopes and a maximum of 10 epitopes were found. Several amino acid residues involved in binding FasL, such as C66, R87, L90, E93 and H126, were presented within the epitopes. Serum containing a large amount of anti‐Fas autoantibody from silicosis patients inhibited the growth of a Fas‐expressing human cell line, but did not inhibit the growth of a low Fas‐expresser nor a Fas‐expresser in which the Fas gene had been silenced by small interference RNA. All epitopes in the intracellular region of Fas were located in the death domain. The possible roles of anti‐Fas autoantibody detected in healthy volunteers and patients with silicosis or autoimmune diseases are discussed here.

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