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101.
102.
103.
Kramer J Böhrnsen F Lindner U Behrens P Schlenke P Rohwedel J 《Cellular and molecular life sciences : CMLS》2006,63(5):616-626
Microfracture of subchondral bone results in intrinsic repair of cartilage defects. Stem or progenitor cells from bone marrow
have been proposed to be involved in this regenerative process. Here, we demonstrate for the first time that mesenchymal stem
(MS) cells can in fact be recovered from matrix material saturated with cells from bone marrow after microfracture. This also
introduces a new technique for MS cell isolation during arthroscopic treatment. MS cells were phenotyped using specific cell
surface antibodies. Differentiation of the MS cells into the adipogenic, chondrogenic and osteogenic lineage could be demonstrated
by cultivation of MS cells as a monolayer, as micromass bodies or mesenchymal microspheres. This study demonstrates that MS
cells can be attracted to a cartilage defect by guidance of a collagenous matrix after perforating subchondral bone. Protocols
for application of MS cells in restoration of cartilage tissue include an initial invasive biopsy to obtain the MS cells and
time-wasting in vitro proliferation and possibly differentiation of the cells before implantation. The new technique already includes attraction
of MS cells to sites of cartilage defects and therefore may overcome the necessity of in vitro proliferation and differentiation of MS cells prior to transplantation.
Received 3 November 2005; received after revision 15 December 2005; accepted 4 January 2006 相似文献
104.
Betaine homocysteine S-methyltransferase: just a regulator of homocysteine metabolism? 总被引:1,自引:0,他引:1
Betaine homocysteine methyltransferase (BHMT), a Zn2+-dependent thiolmethyltransferase, contributes to the regulation of homocysteine levels, increases in which are considered
a risk factor for cardiovascular diseases. Most plasma homocysteine is generated through the liver methionine cycle, in which
BHMT metabolizes approximately 25% of this non-protein amino acid. This process allows recovery of one of the three methylation
equivalents used in phosphatidylcholine synthesis through transmethylation, a major homocysteine-producing pathway. Although
BHMT has been known for over 40 years, the difficulties encountered in its isolation precluded detailed studies until very
recently. Thus, the last 10 years, since the sequence became available, have yielded extensive structural and functional data.
Moreover, recent findings offer clues for potential new functions for BHMT. The purpose of this review is to provide an integrated
view of the knowledge available on BHMT, and to analyze its putative roles in other processes through interactions uncover
to date.
Received 26 May 2006; received after revision 3 July 2006; accepted 24 August 2006 相似文献
105.
Epigenetic asymmetry of imprinted genes in plant gametes 总被引:12,自引:0,他引:12
Gutiérrez-Marcos JF Costa LM Dal Prà M Scholten S Kranz E Perez P Dickinson HG 《Nature genetics》2006,38(8):876-878
Plant imprinted genes show parent-of-origin expression in seed endosperm, but little is known about the nature of parental imprints in gametes before fertilization. We show here that single differentially methylated regions (DMRs) correlate with allele-specific expression of two maternally expressed genes in the seed and that one DMR is differentially methylated between gametes. Thus, plants seem to have developed similar strategies as mammals to epigenetically mark imprinted genes. 相似文献
106.
Horvath A Boikos S Giatzakis C Robinson-White A Groussin L Griffin KJ Stein E Levine E Delimpasi G Hsiao HP Keil M Heyerdahl S Matyakhina L Libè R Fratticci A Kirschner LS Cramer K Gaillard RC Bertagna X Carney JA Bertherat J Bossis I Stratakis CA 《Nature genetics》2006,38(7):794-800
Phosphodiesterases (PDEs) regulate cyclic nucleotide levels. Increased cyclic AMP (cAMP) signaling has been associated with PRKAR1A or GNAS mutations and leads to adrenocortical tumors and Cushing syndrome. We investigated the genetic source of Cushing syndrome in individuals with adrenocortical hyperplasia that was not caused by known defects. We performed genome-wide SNP genotyping, including the adrenocortical tumor DNA. The region with the highest probability to harbor a susceptibility gene by loss of heterozygosity (LOH) and other analyses was 2q31-2q35. We identified mutations disrupting the expression of the PDE11A isoform-4 gene (PDE11A) in three kindreds. Tumor tissues showed 2q31-2q35 LOH, decreased protein expression and high cyclic nucleotide levels and cAMP-responsive element binding protein (CREB) phosphorylation. PDE11A codes for a dual-specificity PDE that is expressed in adrenal cortex and is partially inhibited by tadalafil and other PDE inhibitors; its germline inactivation is associated with adrenocortical hyperplasia, suggesting another means by which dysregulation of cAMP signaling causes endocrine tumors. 相似文献
107.
108.
Foser S Redwanz I Ebeling M Heizmann CW Certa U 《Cellular and molecular life sciences : CMLS》2006,63(19-20):2387-2396
A hallmark of resistance to type I interferons (IFNs) is the lack of antiproliferative responses. We show here that costimulation with IFN-alpha and transforming growth factor beta-1 (TGF-beta) potentiates antiproliferative activity in a sensitive (ME15) and resistant (D10) human melanoma cell line. A DNA microarray-based search for proliferation control genes involved that are cooperatively activated by IFN-alpha and TGF-beta, yielded 28 genes. Among these are the insulin-like growth factor-binding protein 3 (IGFBP3) and the calcium-binding protein S100A2; we demonstrate, that recombinant IGFBP3 protein is a potent growth inhibitor requiring TGF-beta activity. The antiproliferative activity of S100A2 is significantly enhanced by IFN-alpha in stably transfected ME15 or D10 cell lines. We show for the first time that IFN-alpha is a potent inducer of intracellular calcium release required for activation of S100A2. Our study provides a functional link between IFN-alpha and TGF-beta signaling and extends the function of IFN signaling to calcium-sensitive processes. 相似文献
109.
Mangold U 《Cellular and molecular life sciences : CMLS》2006,63(18):2095-2101
In contrast to the considerable interest in the oncogene ornithine decarboxylase (ODC) and in the family of antizymes with
regard to cell proliferation and tumorigenesis, the endogenous antizyme inhibitor (AZI) has been less well studied. AZI is
highly homologous to the enzyme ODC but does not possess any decarboxylase activity. Elevated ODC activity is associated with
most forms of human malignancies. Antizymes bind ODC, inhibit ODC activity and promote the ubiquitin-independent degradation
of ODC. Consequently they are proposed as tumor suppressors. In particular, the most studied member of the antizyme family,
antizyme 1, has been demonstrated to play a role in tumor suppression. AZI inactivates all members of the antizyme family,
reactivates ODC and prevents the proteolytic degradation of ODC, which may suggest a role for AZI in tumor progression.
Received 9 December 2005; received after revision 13 April 2006; accepted 1 June 2006 相似文献
110.
Wang X Rochon M Lamprokostopoulou A Lünsdorf H Nimtz M Römling U 《Cellular and molecular life sciences : CMLS》2006,63(19-20):2352-2363
Commensal Escherichia coli form biofilms at body temperature by expressing the extracellular matrix components curli fimbriae and cellulose. The role of curli fimbriae and cellulose in the interaction of commensal E. coli with the intestinal epithelial cell line HT-29 was investigated. Expression of curli fimbriae by the typical commensal isolate E. coli TOB1 caused adherence and internalization of the bacteria and triggered IL-8 production in HT-29 cells. In particular, induction of IL-8 production was complex and involved curli-bound flagellin. While cellulose alone had no effect on the interaction of TOB1 with HT-29 cells, co-expression of cellulose with curli fimbriae decreased adherence to, internalization and IL-8 induction of HT-29 cells. Investigation of a panel of commensal isolates showed a partial correlation between expression of curli fimbriae and enhanced internalization and IL-8 production. In addition, a high immunostimulatory flagellin was identified. Thus, the consequences of expression of extracellular matrix components on commensal bacterial-host interactions are complex. 相似文献