Galectin-3 stimulates uptake of extracellular Ca2+ in human Jurkat T-cells

AbstractGalectin-3, a mammalian galactoside-binding protein, is not expressed in the Jurkat T-lymphoblastoid cell line. However, Jurkat cells express surface glycoprotein receptors for galectin-3, one of which is shown to be the glycosylated heavy chain of CD98 (4F2 antigen), a T-cell activation marker. Addition of galectin-3 to Jurkat cells triggers a sustained influx of extracellular Ca2+ in a concentration dependent manner. The induced increase in cytosolic [Ca2+]i is blocked by sugar hapten inhibitors of galectin-3. The galectin-3-induced effect is insensitive to voltage-gated Ca2+ channel antagonists such as prenylamine, nifedipine and diltiazem and to pertussis toxin but is inhibited by cholera toxin. The results suggest that galectin-3 released by accessory cells such as macrophages may bind in vivo to T-cell activation antigens and also participate in Ca2+ signalling

Temporary Disruption of the Retinal Basal Lamina and Its Effect on Retinal Histogenesis

AbstractAn experimental paradigm was devised to remove the retinal basal lamina for defined periods of development: the basal lamina was dissolved by injecting collagenase into the vitreous of embryonic chick eyes, and its regeneration was induced by a chase with mouse laminin-1 and α2-macroglobulin. The laminin-1 was essential in reconstituting a new basal lamina and could not be replaced by laminin-2 or collagen IV, whereas the macroglobulin served as a collagenase inhibitor that did not directly contribute to basal lamina regeneration. The regeneration occurred within 6 h after the laminin-1 chase by forming a morphologically complete basal lamina that included all known basal lamina proteins from chick embryos, such as laminin-1, nidogen-1, collagens IV and XVIII, perlecan, and agrin. The temporary absence of the basal lamina had dramatic effects on retinal histogenesis, such as an irreversible retraction of the endfeet of the neuroepithelial cells from the vitreal surface of the retina, the formation of a disorganized ganglion cell layer with an increase in ganglion cells by 30%, and the appearance of multiple retinal ectopias. Finally, basal lamina regeneration was associated with aberrant axons failing to correctly enter the optic nerve. The present data demonstrate that a transient disruption of the basal lamina leads to dramatic and probably irreversible aberrations in the histogenesis in the developing central nervous system

Embryonic Synthesis of the Inner Limiting Membrane and Vitreous Body

PURPOSE. The inner limiting membrane (ILM) and the vitreous body (VB) are major parts of the extracellular matrix of the eye. The present study was undertaken to investigate the synthesis and turnover of the ILM and VB in chick and human embryonic and postembryonic eye development. METHODS. The abundance of ILM and VB proteins was determined by Western blot analysis using samples from chick and human VB of different ages. The mRNA expression of the ILM proteins in lens was determined by in situ hybridization and RT-PCR. RESULTS. Based on the abundance of mRNA expression, the prominent sources of ILM and VB proteins in chick eyes are the lens and ciliary body. In chick, ILM and VB matrix proteins were most abundant in embryonic VB, and their concentration declined precipitously after hatching. Most ILM and VB proteins were no longer detectable in the adult VB. In humans, a similar developmentally regulated expression of ILM and VB proteins in VB was detected: The highest concentrations of ILM and VB proteins were detected in fetal VB, the lowest in the adult VB. The decline in ILM and VB protein synthesis occurred within the first 2 years of life. CONCLUSIONS. The abundance of ILM and VB proteins in the embryonic VB, their sharp decline at postembryonic stages, and their very low abundance in the adult VB show that ILM and VB are assembled during embryogenesis and are maintained throughout life with minimum turnover

Role of p53 in leukemogenesis of chronic myeloid leukemia

This review attempts to provide current information on the role played by the p53 gene in normal and leukemic hematopoiesis with particular emphasis on chronic myeloid leukemia. On the basis of the currently available data we can argue that p53 acts as a negative regulator of proliferation of myeloid mature cells and CD34+ progenitors, and its action is mediated through changes in cell cycle kinetics, mainly before the S phase. The p53‐dependent pathway is also regulated by several proteins, including p16, p21, p27 (cyclin‐dependent kinase [CDK] inhibitors), and a few oncogenes (bcl‐2, bax, MDM‐2). Although there is some information about the changes in the p53 gene seen in various types of leukemia, the functions and biological importance of these changes in the pathogenesis of leukemia are still largely elusive. During the past several years, accumulated evidence suggests that changes in the p53 gene are commonly associated with blast crisis of chronic myeloid leukemia (CML) but rarely with chronic phase, and they are represented by rearrangements, deletions and point mutations. As for most of the tumors, the majority of point mutations occur between exons 4 and 8 (hot regions). In patients with CML in blastic crisis the most frequent mechanism of p53 inactivation is complete deletion of one allele in association with a point mutation in the remaining allele. As far as the loss of p53 function in CML patients in blastic crisis is concerned, we believe that it can play a key role, in combination with other genetic changes (p210 BCR/ABL, Rb gene abnormalities, CDK inhibitors alterations), in inducing disturbances in proliferation, differentiation and apoptosis of the leukemic clone. However, the exact relationship between p210 BCR/ABL, the mutant p53, and putative alterations in CDK inhibitors (p21, p16, etc.) in the pathogenesis of blastic transformation of CML needs to be clarified. We think that experiments designed to ascertain whether sustained expression of a mutant p53 is capable of causing differentiation arrest of Ph‐positive hematopoietic cells in vitro may shed more light on this issue. It is also conceivable that a therapeutically‐induced correction of the expression of CDK inhibitors in p53 mutant CML cells can significantly influence the cell cycle machinery and possibly suppress the increased proliferative activity of blastic cells. Hopefully, highly efficient and targeted wild‐type p53 delivery vectors may, in the future, lead to a substantial clinical improvement in CML patients carrying p53 abnormalities and undergoing a blastic transformation of the disease

Abnormal epression of N-CAM (CD56) adhesion molecule on myeloid and progenitor cells from chronic myeloid leukaemia

Bone marrow and peripheral blood samples from 36 patients with Philadelphia chromosome positive chronic myelogenous leukemia (Ph+ CML) (30 in chronic phase, four in accelerated phase, and two in blastic crisis) were tested with two CD56 monoclonal antibodies (My31 and Eric 1) using the Facscan flow cytometer. Two- and three-color fluorescence experiments indicated that CD13+/CD33+ myeloid cells from 19 out of the 36 patients were positive for CD56 in 12-77% of the cells. In contrast, no CD56 positivity was documented in myeloid cells from bone marrow (BM) of healthy donors. Immunocytochemical staining (APAAP technique) of CML peripheral blood (PB) and BM slides showed that CD56 expression was detectable from the myelocyte stage with the strongest staining in the metamyelocyte stage. Neutrophils were negative both by flow cytometry and APAAP analysis. In individual CML patients, an increasing number of CD56+ cells were recovered with progressively higher density cuts (1.065-1.077 g/ml), supporting the concept that the antigen level tends to increase during myeloid differentiation. Furthermore, 19% of CML patients coexpressed CD56 and CD34 antigens in 10-45% of the CD34+ cells. The myeloid nature of CD56+/CD34+ CML cells has been ascertained by granulocyte-macrophage colony-forming unit (CFU-GM) assays on CD56+ cells sorted on FACS. Furthermore, in six out of eight CML patients in whom we performed a comparative BM and PB analysis, we found that the CD56 expression was brighter and the number of positive cells significantly higher in the peripheral blood myeloid cells as compared to their BM counterpart. In short-term liquid cultures, low doses (50 U/ml) of alpha interferon down-regulated the CD56 expression in CML cells, accompanied by a significant reduction of the Ph positivity. In conclusion, the expression of CD56 on CML myeloid elements seems to represent an aberrant phenomenon which could affect the cell homing mechanisms and, probably, the pattern of tumor cell dissemination. In patients with CD56+ CML, its detection could be further used as a means of monitoring patients undergoing bone marrow transplantation, since its reappearance is associated with early relapse of the disease

Trajectory Tracking Control in Real-Time of Dual-Motor-Driven Driverless Racing Car Based on Optimal Control Theory and Fuzzy Logic Method

To improve the accuracy and timeliness of the trajectory tracking control of the driverless racing car during the race, this paper proposes a track tracking control method that integrates the rear wheel differential drive and the front wheel active steering based on optimal control theory and fuzzy logic method. The model of the lateral track tracking error of the racing car is established. The model is linearized and discretized, and the quadratic optimal steering control problem is constructed. Taking advantage of the differential drive of dual-motor-driven racing car, the dual motors differential drive fuzzy controller is designed and integrated driving with active steering control. Simulation analysis and actual car verification show that this integrated control method can ensure that the car tracks different race tracks well and improve the track tracking control accuracy by nearly 30%

A critical function of the pial basement membrane in cortical histogenesis

Mice with a targeted deletion of the nidogen-binding site of laminin gamma1 were used to study the function of the pial basement membrane in cortical histogenesis. The pial basement membrane in the mutant embryos assembled but was unstable and disintegrated at random segments. In segments with a disrupted basement membrane, radial glia cells were retracted from the pial surface, and radially migrating neurons, including Cajal- Retzius cells and cortical plate neurons, passed the meninges or terminated their migration prematurely. By correlating the disruptions in the pial basal lamina with changes in the morphology of radial glia cells, the aberrant migration of Cajal-Retzius cells, and subsequent dysplasia of cortical plate neurons, the present data establish a causal relationship of proper cortical histogenesis with the presence of an intact pial basement membrane

Metabolomics analysis of metabolic effects of nicotinamide phosphoribosyltransferase (NAMPT) inhibition on human cancer cells.

Nicotinamide phosphoribosyltransferase (NAMPT) plays an important role in cellular bioenergetics. It is responsible for converting nicotinamide to nicotinamide adenine dinucleotide, an essential molecule in cellular metabolism. NAMPT has been extensively studied over the past decade due to its role as a key regulator of nicotinamide adenine dinucleotide-consuming enzymes. NAMPT is also known as a potential target for therapeutic intervention due to its involvement in disease. In the current study, we used a global mass spectrometry-based metabolomic approach to investigate the effects of FK866, a small molecule inhibitor of NAMPT currently in clinical trials, on metabolic perturbations in human cancer cells. We treated A2780 (ovarian cancer) and HCT-116 (colorectal cancer) cell lines with FK866 in the presence and absence of nicotinic acid. Significant changes were observed in the amino acids metabolism and the purine and pyrimidine metabolism. We also observed metabolic alterations in glycolysis, the citric acid cycle (TCA), and the pentose phosphate pathway. To expand the range of the detected polar metabolites and improve data confidence, we applied a global metabolomics profiling platform by using both non-targeted and targeted hydrophilic (HILIC)-LC-MS and GC-MS analysis. We used Ingenuity Knowledge Base to facilitate the projection of metabolomics data onto metabolic pathways. Several metabolic pathways showed differential responses to FK866 based on several matches to the list of annotated metabolites. This study suggests that global metabolomics can be a useful tool in pharmacological studies of the mechanism of action of drugs at a cellular level