Setting the conditions for efficient, robust and reproducible generation of functionally active neurons from adult subventricular zone-derived neural stem cells.

Although new culture conditions enable homogeneous and long-term propagation of radial glia-like neural stem (NS) cells in monolayer and serum-free conditions, the efficiency of the conversion of NS cells into terminally differentiated, functionally mature neurons is relatively limited and poorly characterized. We demonstrate that NS cells derived from adult mouse subventricular zone robustly develop properties of mature neurons when exposed to an optimized neuronal differentiation protocol. A high degree of cell viability was preserved. At 22 days in vitro, most cells (65%) were microtubule-associated protein 2(+) and coexpressed gamma-aminobutyric acid (GABA), GAD67, calbindin and parvalbumin. Nearly all neurons exhibited sodium, potassium and calcium currents, and 70% of them fired action potentials. These neurons expressed functional GABA(A) receptors, whereas activable kainate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and N-methyl-D-aspartic acid receptors were present in approximately 80, 30 and 2% of cells, respectively. Antigenic and functional properties were efficiently and reliably reproduced across experiments and cell passages (up to 68). This is the first report showing a consistent and reproducible generation of large amounts of neurons from long-term passaged adult neural stem cells. Remarkably, the neuronal progeny carries a defined set of antigenic, biochemical and functional characteristics that make this system suitable for studies of NS cell biology as well as for genetic and chemical screenings.

Pathological, clinical and prognostic characteristics of breast cancer in Central Sudan versus Northern Italy: implications for breast cancer in Africa.

AIMS: In patients of Black African ethnicity, breast cancer is reportedly characterized by aggressive, poorly differentiated phenotype(s). To highlight possible differences between breast cancer in indigenous sub-Saharan African and European patients, two breast cancer case series, from Central Sudan (Khartoum) and Northern Italy (Milan), were compared for clinicopathological characteristics, expression of oestrogen receptor (ER), progesterone receptor (PR), Her-2/neu, basal cytokeratin (CK) 5/6 and CK17, and breast cancer subtypes. METHODS AND RESULTS: After careful antigen retrieval, 114 and 138 consecutive formalin-fixed paraffin-embedded (FFPE) breast cancer cases from the Radiation and Isotope Centre (Khartoum) and from MultiMedica (Milan), respectively, were screened by immunohistochemistry for ER, PR, Her-2/neu, CK5/6 and CK17. Compared with the Italian patients, the Sudanese patients were younger (P < 0.0001) and their tumours were larger (P < 0.0001), more advanced in stage (P < 0.00001), higher grade (P < 0.00001) and more frequently positive for nodal metastases (P < 0.00001). ER expression varied between the two series (P < 0.0008), but no significant differences were found for PR (P < 0.32), combined hormone receptors (P < 0.12), Her-2/neu (P < 0.09), CK5/6 (P < 0.1), CK17 (P = 0.4), combined basal CK status (P = 1) or breast cancer subtypes (P = 0.12). CONCLUSION: The differences between the Sudanese and Italian breast cancer series reflect stage at diagnosis rather than intrinsic biological characteristics. This may have relevant implications for breast cancer prevention and treatment in Africa.

Technical note: Improved method for rapid DNA extraction of mastitis pathogens directly from milk.

Efficient control against bovine mastitis requires sensitive, rapid, and specific tests to detect and identify the main bacteria that cause heavy losses to the dairy industry. Molecular detection of pathogenic microorganisms is based on DNA amplification of the target pathogen. Therefore, efficient extraction of DNA from pathogenic bacteria is a major step. In this study, we aimed to develop a specific, sensitive, and rapid method to extract DNA directly from the main gram-positive bacteria known to cause bovine mastitis (Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus uberis) found in milk samples. The DNA extraction method is based on the lysing and nuclease-inactivating properties of the chaotropic agent, guanidinium thiocyanate, together with the nucleic acid-binding properties of the silica particles. An efficient protocol consisting of 6 basic steps (3 of which were done twice) was developed and applied directly to milk samples. Absence of PCR inhibitors and DNA quality were evaluated by PCR amplification of the species-specific DNA sequences of the target bacteria. The level of sensitivity achieved in our experiments is applicable to milk sample analysis without sample enrichment.

Ctla4 and multiple sclerosis in the Italian population.

CTLA4 protein is a receptor molecule that plays a critical role as a negative regulator of the immune response. Therefore, genetic variations in CTLA4 may confer susceptibility to autoimmune diseases such as multiple sclerosis (MS). In order to investigate the association of two CTLA4 polymorphisms (+49 A/G and -318 C/T) with multiple sclerosis, sporadic MS patients and healthy controls from Italy were genotyped through direct DNA sequencing. Considering single-loci variations, no differences in the allelic and genotypic frequencies between patients and controls were found. However, considering a putative interaction at the two loci, the T/G combination was more frequently observed in patients than in controls. This result suggests that this allelic combination of the CTLA4 polymorphisms may be involved in the susceptibility to MS in the Italian population.

Identification of a novel polymorphism in the fibronectin type II domain of the SEL1L gene and possible relation to the persistent hyperinsulinemic hypoglycemia of infancy.

SEL1L, a human gene located on chromosome 14q24.3-q31, is highly expressed in adult pancreas. It is proximal to D14S67 (IDDM11) a proposed type I diabetes susceptibility locus. Considering the organ specific expression of SEL1L, a fundamental role of SEL1L in pancreatic growth can be hypothesized. While screening for mutations in young diabetic patients, in children affected by persistent hyperinsulinemic hypoglycemia of infancy (PHHI), in patients with non-functional endocrine tumours and in over 100 control subjects, we identified a novel polymorphism (D162G) residing on the fourth exon of the gene. This exon encodes for the fibronectin type II domain and the nucleotide change involves a highly conserved amino acid. The D162G polymorphism induces a major change in the amino acid composition producing a possible disruptive role in collagen binding.

Interleukin-1B polymorphism is associated with age at onset of Alzheimer's disease.

Interleukin-1alpha (IL-1alpha) and IL-1beta are two pro-inflammatory cytokines involved in the pathogenesis of Alzheimer's disease (AD). The genes coding for IL-1alpha (IL-1A) and for IL-1beta (IL-1B) are clustered in chromosome 2q14-2q14.2. In a previous work, we investigated the role of IL-1A promoter polymorphism (-889 position) in AD pathogenesis: IL-1A -889 TT genotype was associated with sporadic early onset AD. We now report the study on polymorphism of exon 5 IL-1B in position +3953, the nearest polymorphism to -889 IL-1A. We found that the genotype distribution of IL-1B +3953 varied significantly between patients with early and late onset of AD (P<0.0001). Patients carrying IL-1B +3953 CT or TT genotypes had 4 or 5 years anticipation of AD onset (P=0.0034; odds ratio for early onset, 3.01) and 7 years anticipation if they also carried the IL-1A -889 TT genotype (P<0.0001; odds ratio for early onset, 7.4). These data further support a role for inflammation-related genes in AD or indicate linkage disequilibrium with an unknown chromosome 2 locus.

A mitochondrial tRNA(His) gene mutation causing pigmentary retinopathy and neurosensorial deafness.

We have identified a heteroplasmic G to A mutation at position 12,183 of the mitochondrial transfer RNA Histidine (tRNA(His)) gene in three related patients. These phenotypes varied according to mutation heteroplasmy: one had severe pigmentary retinopathy, neurosensorial deafness, testicular dysfunction, muscle hypotrophy, and ataxia; the other two had only retinal and inner ear involvement. The mutation is in a highly conserved region of the T(psi)C stem of the tRNA(His) gene and may alter secondary structure formation. This is the first described pathogenic, maternally inherited mutation of the mitochondrial tRNA(His) gene.

Production of a monoclonal antibody directed against the recombinant SEL1L protein.

SEL1L, highly similar to the C elegans sel-1 gene, is a recently cloned human gene whose function is under investigation. SEL1L is differentially expressed in tumors and normal tissues and seems to play a role in tumor growth and aggressiveness. We used the recombinant N-terminus of the SEL1L protein to immunize a Balb/c mouse and produce a monoclonal antibody. A hybridoma secreting an antibody specifically reacting on the SEL1L recombinant fragment was selected. This monoclonal antibody, named MSel1, recognizes the SEL1L protein by Western blotting, immunofluorescence and immunohistochemistry on normal and tumor cells. MSel1 is able to recognize SEL1L even on archival tumor specimens and is therefore particularly appropriate to study SEL1L involvement in tumor progression.

Allelic polymorphisms in the transcriptional regulatory region of human SEL1L.

In this work, we explored the existence of genetic variants within the SEL1L transcriptional regulatory region by direct sequencing of the basal promoter. SEL1L is the human ortholog of the Caenorhabditis elegans gene sel-1, a negative regulator of LIN-12/NOTCH receptor proteins. To understand the relation in SEL1L transcription pattern observed in different epithelial cells, we analysed its promoter activity. We found it to be considerably higher only in pancreatic cells. We then looked for the presence of genetic variability within this region by sequencing the minimal promoter of 63 individuals (126 alleles); two new and associated polymorphic variants were found only in few lung carcinoma bearing patients. The functional effects of this polymorphism was analysed by transient transfection assay which resulted in a significant increase in the transcriptional activity of the gene.

No evidence for SEL1L as a candidate gene for IDDM11-conferred susceptibility.

BACKGROUND: The SEL1L gene is located on human chromosome 14q24.3-31 close to D14S67 which has been previously proposed to be a type 1 diabetes mellitus locus (IDDM11). Sel-1 is a negative regulator of the Notch signalling pathway and SEL1L is selectively expressed in adult pancreas and islets of Langerhans. This suggests that SEL1L may be a candidate gene for IDDM11. METHODS: We have analysed two newly identified CA-repeat polymorphisms within the genomic sequence of the SEL1L locus for association with type 1 diabetes mellitus (T1DM) in 152 Danish T1DM-affected sib-pair families and in 240 Sardinian families (229 simplex and 11 sib-pair families). RESULTS: No evidence for association of the two SEL1L markers with T1DM was observed in either the Danish or the Sardinian families. We have also used allelic sharing methods to analyse linkage with T1DM in the IDDM11 region using the same markers and the Danish collection of affected sib-pair families. No evidence of linkage was observed (Z(max)=0.86). CONCLUSION: Although several lines of evidence suggest that SEL1L might be a candidate for IDDM11-conferred susceptibility to T1DM the present study does not support this hypothesis.

Cloning and functional analysis of SEL1L promoter region, a pancreas-specific gene.

We examined the promoter activity of SEL1L, the human ortholog of the C. elegans gene sel-1, a negative regulator of LIN-12/NOTCH receptor proteins. To understand the relation in SEL1L transcription pattern observed in different epithelial cells, we determined the transcription start site and sequenced the 5' flanking region. Sequence analysis revealed the presence of consensus promoter elements--GC boxes and a CAAT box--but the absence of a TATA motif. Potential binding sites for transcription factors that are involved in tissue-specific gene expression were identified, including: activator protein-2 (AP-2), hepatocyte nuclear factor-3 (HNF3 beta), homeobox Nkx2-5 and GATA-1. Transcription activity of the TATA-less SEL1L promoter was analyzed by transient transfection using luciferase reporter gene constructs. A core basal promoter of 302 bp was sufficient for constitutive promoter activity in all the cell types studied. This genomic fragment contains a CAAT and several GC boxes. The activity of the SEL1L promoter was considerably higher in mouse pancreatic beta cells (beta TC3) than in several human pancreatic neoplastic cell lines; an even greater reduction of its activity was observed in cells of nonpancreatic origin. These results suggest that SEL1L promoter may be a useful tool in gene therapy applications for pancreatic pathologies.

Melanoma antigen genes 1 and 2 are differentially expressed in human gastric and cardial carcinomas.

BACKGROUND: MAGE genes encode for tumor-rejection antigens and are expressed in tumors of different histologic types but not in normal tissues, with the exception of testis and placenta. The aim of this study was to evaluate the frequency of MAGE-1 and -2 expression in gastric and in cardial carcinomas; these conditions have been described as two distinct diseases, having different etiologies, epidemiologic patterns, and gene mutations. METHODS: Two groups of patients were studied: patients with distal gastric carcinoma and patients with carcinoma of the cardia. A group of patients with intestinal metaplasia in the gastric mucosa and controls were also included. All of them underwent upper GI endoscopy. Paired biopsy specimens were taken for routine histology and for RNA extraction, to study the expression of MAGE-1 and -2 genes. RESULTS: None of the intestinal metaplastic samples or controls expressed MAGE-1 and -2 at detectable levels. Whereas 40% of the gastric cancer patients expressed either MAGE-1 or -2, 26.6% transcribed both. In the cardial cancer group, 20% of the cases expressed at least one MAGE, and only 6.6% expressed both genes. These results might reinforce the concept that cancer of the cardia is a distinct neoplastic disease with regard to esophageal and gastric (distal) carcinomas. CONCLUSIONS: Here we show that MAGE gene expression occurs in advanced stages of gastric and cardial cancer and therefore appears to be a late event. This might point to a reconsideration of their potential role in cancer immunotherapy.

The expression of SEL1L and TAN-1 in normal and neoplastic cells.

We have previously reported on the isolation and chromosomal mapping of a novel human gene (SEL1L), which shows sequence similarity to sel-1, an extragenic suppressor of C. elegans. sel-1 functions as a negative regulator of lin-12 activity, the latter being implicated in the control of diverse cellular differentiation events. In the present study we compare the expression patterns of SEL1L and TAN-1, the human ortholog of lin-12 in normal and neoplastic cells. We found that, whereas both genes are expressed in fetal tissues at similar levels, they are differentially expressed in normal adult and neoplastic cells. In normal adult cells SEL1L is generally present at very low levels; only in the cells of the pancreas does it show maximum expression. By contrast, SEL1L is generally well represented in most neoplastic cells but not in those of pancreatic and gastric carcinomas, where transcription is either downregulated or completely repressed. TAN-1 on the other hand is well represented in almost all normal and neoplastic cells, with very few exceptions. Our observations suggest that SEL1L is presumably implicated in pancreatic and gastric carcinogenesis and that, along with TAN-1, it is very important for normal cell function. Alterations in the expression of SEL1L may be used as a prognostic marker for gastric and pancreatic cancers.

SEL1L, the human homolog of C. elegans sel-1: refined physical mapping, gene structure and identification of polymorphic markers.

We have cloned the human full-length cDNA SEL1L, which is highly similar to the C. elegans sel-1 gene, an important negative regulator of the "notch" pathway which acts as a key regulator of the cellular proliferation and specification processes in both vertebrates and invertebrates. The SEL1L gene maps to 14q24.3-31 and here we report its fine localization by HAPPY mapping, which determines its molecular distance to microsatellite markers isolated in the region. We have found two new polymorphic (CA)n microsatellites located in the gene, and have identified the exon-intron boundaries. The gene is composed of 21 exons spanning 70 kb of genomic DNA. Human SEL1L protein exhibits a high degree of similarity compared to the mouse and nematode homologs.

Association of early-onset Alzheimer's disease with an interleukin-1alpha gene polymorphism.

Overexpression of the pluripotent cytokine interleukin-1 (IL-1) by microglial cells correlates with formation of neuritic beta-amyloid plaques in Alzheimer's disease (AD). We evaluated polymorphisms in the genes coding for the IL-1alpha, IL-1beta, and IL-1 receptor antagonist cytokines, and tested their association with the occurrence and age at onset of sporadic AD. We found a strong association between the IL-1A T/T genotype and AD onset before 65 years of age (odds ratio, 4.86), with carriers of this genotype showing an onset of disease 9 years earlier than IL-1A C/C carriers. A weaker association with the age at onset was also shown for the IL-1B and IL-1RN genes. These data suggest either a direct effect of the IL-1 gene family, mainly IL-1A, on the clinical onset of AD, or a linkage dysequilibrium with an unknown locus relevant to AD on chromosome 2.

Molecular characterization of a novel endonuclease (Xib) and possible involvement in lysosomal glycogen storage disorders.

We cloned and partially characterized a human endonuclease (Xib) which shows sequence homologies to pancreatic DNase I but an enzymatic activity closer to DNase II. We report on the structural differences found between Xib and other recently cloned human DNases. Fluores cence microscopy analysis of transiently transfected cells with Xib::pEGFP constructs indicate that the protein is located in the cytoplasm and possibly anchored to a membrane, as deduced from a hydrophobic amino acid stretch present at the C-terminal end. Xib is overexpressed in muscle and cardiac tissues and is alternately spliced in several normal and neoplastic cells. In situ hybridization studies using human cardiac and muscle biopsies indicate accumulation of Xib transcript in the vacuoles of muscle cells from patients affected by vacuolar myopathy as acid maltase deficiency; however, no point mutations were detected in their DNA.