Fibronectin and transforming growth factor beta contribute to erythropoietin resistance and maladaptive cardiac hypertrophy

The use of recombinant human erythropoietin (rhEPO) to promote repair and minimize cardiac hypertrophy after myocardial infarction has had disappointing outcomes in clinical trials. We hypothesized that the beneficial non-hematopoietic effects of rhEPO against cardiac hypertrophy could be offset by the molecular changes initiated by rhEPO itself, leading to rhEPO resistance or maladaptive hypertrophy. This hypothesis was investigated using an isoproterenol-induced model of myocardial infarct and cardiac remodelling with emphasis on hypertrophy. In h9c2 cardiomyocytes, rhEPO decreased isoproterenol-induced hypertrophy, and the expression of the pro-fibrotic factors fibronectin, alpha smooth muscle actin and transforming growth factor beta-1 (TGF-β1). In contrast, by itself, rhEPO increased the expression of fibronectin and TGF-β1. Exogenous TGF-β1 induced a significant increase in hypertrophy, which was further potentiated by rhEPO. Exogenous fibronectin not only induced hypertrophy of cardiomyocytes, but also conferred resistance to rhEPO treatment. Based on these findings we propose that the outcome of rhEPO treatment for myocardial infarction is determined by the baseline concentrations of fibronectin and TGF-β1. If endogenous fibronectin or TGF-β levels are above a certain threshold, they could cause resistance to rhEPO therapy and enhancement of cardiac hypertrophy, respectively, leading to maladaptive hypertrophy.     

Polymorphisms in the promoter region of ESR2 gene and breast cancer susceptibility

Genetic variations like single nucleotide polymorphisms (SNPs) in genes involved in estrogen biosynthesis, metabolism and signal transduction have been suggested to affect breast cancer susceptibility. In this study we tested the hypothesis that polymorphisms in the promoter of ESR2 gene may be associated with increased risk for breast cancer. We analyzed three SNPs in the promoter region of human ESR2 gene by means of allele-specific tetra-primer PCR. A total of 318 sporadic breast cancer cases and 318 age-matched controls were included in the study. With regard to homozygous genotypes, women with sporadic breast cancer more frequently carried the CC genotype of ESR2 promoter SNP rs2987983 (OR 1.99, p = 0.005). Calculation of allele positivity demonstrated that presence of T allele of this SNP was more frequent in healthy women. Our data suggest that a SNP in the promoter region of ESR2 gene might be able to affect breast cancer risk. These results further support the emerging hypothesis that ERβ is an important factor in breast cancer development.     

Large-scale search of SNPs for type 2 DM susceptibility genes in a Japanese population

The etiology of type 2 diabetes (DM) is polygenic. We investigated here genes and polymorphisms that associate with DM in the Japanese population. Single-nucleotide polymorphisms (SNPs) of 398 derived from 120 candidate genes were examined for association with DM in a population-based case-control study. The study group consisted of 148 cases and 227 controls recruited from Funagata, Japan. No evident subpopulation structure was detected for the tested population. The association tests were conducted with standard allele positivity tables (chi(2) tests) between SNP genotype frequency and case-control status. The independent association of the SNPs from serum triglyceride levels and body mass index was examined by multiple logistic regression analysis. A value of P<0.01 was accepted as statistically significant. Six genes (met proto-oncogene, ATP-binding cassette transporter A1, fatty acid binding protein 2, LDL receptor defect C complementing, aldolase B, and sulfonylurea receptor) were shown to be associated with DM.     

TGF-beta2 neutralization inhibits proliferation and activates apoptosis of cerebellar granule cell precurors in the developing cerebellum

Transforming growth factor beta 2 (TGF-beta2) plays a critical role in growth, differentiation and cell death, but its function in the developing cerebellum is still uncertain. In this study we analyzed the effects of TGF-beta2 on ex vivo developing cerebellar slice cultures. Proliferation of granule cell precursors peaked ex vivo in the same developmental window as in vivo (P8-P14). Addition of recombinant TGF-beta2 could extent the proliferation of granule cell precursors and induced a second late proliferation wave. In contrast, antibody neutralization of TGF-beta2 strongly reduced proliferation and induced neurodegeneration. TGF-beta2 neutralization resulted in apoptotic cells, which showed caspase 3 activation. Taken together our results demonstrate that TGF-beta2 is a novel growth and survival factor for granule cells precursors in the developing cerebellum.     

Simultaneous conjugal transfer in Lactococcus to genes involved in bacteriocin production and reduced susceptibility to bacteriophages

Conjugal matings were performed between Lactococcus lactis DRC1 (a lactose-fermenting (Lac+), bacteriocin-producing (Bac+) strain) and L. lactis HID113 (Lac- and Bac-). Transconjugant derivatives of HID113 were identified on the basis of lactose fermentation, resistance to the DRC1 bacteriocin (dricin) or reduced sensitivity to phage sk1. Regardless of how they were identified, all transconjugants gave fewer and smaller plaques with phages c2 and sk1 than did HID113. All but one of 275 transconjugants tested also produced dricin, suggesting some functional relationship or close genetic linkage between the reduced phage sensitivity and dricin production and resistance. Some transconjugants were also Lac+, but this property was unstable.     

Down-regulation of Toll-like receptor expression in monocyte-derived Langerhans cell-like cells: implications of low-responsiveness to bacterial components in the epidermal Langerhans cells

In the skin, there are unique dendritic cells called Langerhans cells, however, it remains unclear why this particular type of dendritic cell resides in the epidermis. Langerhans cell-like dendritic cells (LCs) can be generated from CD14(+) monocytes in the presence of GM-CSF, IL-4, and TGF-beta1. We compared LCs with monocyte-derived dendritic cells (DCs) generated from CD14(+) monocytes in the presence of GM-CSF and IL-4 and examined the effect of exposure to two distinct bacterial stimuli via Toll-like receptors (TLRs), such as peptidoglycan (PGN) and lipopolysaccharide (LPS) on LCs and DCs. Although stimulation with both ligands induced a marked up-regulation of CD83 expression on DCs, PGN but not LPS elicited up-regulation of expression CD83 on LCs. Consistent with these results, TLR2 and TLR4 were expressed on DCs, whereas only TLR2 was weakly detected on LCs. These findings suggest the actual feature of epidermal Langerhans cells with low-responsiveness to skin commensals.     

Mitogenic response to epidermal growth factor: Relationship to number,affinity, and down-regulation of EGF receptors in three murine embyro cell lines

Swiss 3T3 and C3H-M2 cells have a greater mitogenic response to epidermal growth factor (EGF) than do C3H-10T1/2 cells. The latter cell line, however, has a number of EGF receptors per cell intermediate between the two cell lines that have a more vigorous response to EGF. Scatchard analysis of binding data indicate that all three cell lines have one class of EGF receptor, with indistinguishable affinity for the ligand. When exposed to 10-nM EGF all three cell lines “down-regulate” their EGF receptors with the same time course, and to the same precentage of initial receptors.     

Runx1 is involved in the fusion of the primary and the secondary palatal shelves

Runx1 is expressed in medial edge epithelial (MEE) cells of the palatal shelf. Conditionally rescued Runx1^−/− mice showed limited clefting in the anterior junction between the primary and the secondary palatal shelves, but not in the junction between the secondary palates. In wild type mice, the fusing epithelial surface exhibited a rounded cobblestone-like appearance, while such cellular prominence was less evident in the Runx1 mutants. We also found that Fgf18 was expressed in the mesenchyme underlying the MEE and that locally applied FGF18 induced ectopic Runx1 expression in the epithelium of the palatal explants, indicating that Runx1 was induced by mesenchymal Fgf18 signaling. On the other hand, unpaired palatal explant cultures revealed the presence of anterior-posterior (A-P) differences in the MEE fates and fusion mechanism. Interestingly, the location of anterior clefting in Runx1 mutants corresponded to the region with different MEE behavior. These data showed a novel function of Runx1 in morphological changes in the MEE cells in palatal fusion, which is, at least in part, regulated by the mesenchymal Fgf signaling via an epithelial-mesenchymal interaction.     

Mutational identification of fibroblast growth factor receptor 1 and fibroblast growth factor receptor 2 genes in craniosynostosis in Indian population

OBJECTIVE:

The Objective of this study was to identify the association of mutation of fibroblast growth factor receptor 1 (FGFR1), FGFR2 genes with syndromic as well as non-syndromic craniosynostosis in Indian population.

MATERIALS AND METHODS:

Retrospective analysis of our records from January 2008 to December 2012 was done. A total of 41 cases satisfying the inclusion criteria and 51 controls were taken for the study. A total volume of 3 ml blood from the patient as well as parents was taken. Deoxyribonucleic acid extracted using phenol chloroform extraction method followed by polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS:

There were 33 (80.4%) non-syndromic cases of craniosynostosis while 8 (19.5%) were syndromic. Out of these 8 syndromic cases, 4 were Apert syndrome, 3 were Crouzon syndrome and 1 Pfeiffer syndrome. Phenotypically the most common non-syndromic craniosynostosis was scaphocephaly (19, 57.7%) followed by plagiocephaly in (14, 42.3%). FGFR1 mutation (Pro252Arg) was seen in 1 (2.4%) case of non-syndromic craniosynostosis while no association was noted either with FGFR1 or with FGFR2 mutation in syndromic cases. None of the control group showed any mutation.

CONCLUSION:

Our study proposed that FGFR1, FGFR2 mutation, which confers predisposition to craniosynostosis does not exist in Indian population when compared to the western world.     

Establishment of Hertwig's epithelial root sheath cell line from cells involved in epithelial-mesenchymal transition

The epithelial–mesenchymal transition (EMT) is an important event in the developmental process of various organs. In periodontal development during root formation of a tooth, this EMT has been a subject of controversy. Hertwig’s epithelial root sheath (HERS), consisting of two epithelial layers, plays a role of inducing odontogenesis during root development and thereafter becomes fragmented. Some researchers have maintained that in the process of this fragmentation, some HERS cells change from epithelial to mesenchymal cells. Here, we established a HERS cell line (HERS01a) and examined its gene and protein expression. Immunohistochemical staining and real-time PCR analysis showed that HERS01a cells expressed vimentin and N-cadherin as mesenchymal markers as well as cytokeratin14, E-cadherin, and p63 as epithelial stem cell markers. In the presence of TGF-β, HERS01a cells also expressed many more mesenchymal markers, as well as snail1 and 2 as EMT markers. Taken together, our data show that HERS01a displayed unique features associated with EMT in the root formation process, and will thus be useful for analyzing the biological characteristics of HERS and the molecular mechanism underlying the EMT.     

Epidermal growth factor (EGF) binding to membranes immobilized in microtiter wells and estimation of EGF-related transforming growth factor activity

The binding of radiolabeled epidermal growth factor (EGF) to immobilized A-431 target cell membranes coupled to polyvinyl chloride microtiter wells is described. Saturation curves and Scatchard analysis of the data indicate that the observed binding parameters are consistent with those previously reported. Binding capacity of the membranes are approx. 6.6 pmol EGF per mg membrane protein. Kinetics of ¹²⁵I-EGF binding were slower, however, than reported for binding to membranes in suspension, although binding constants were not greatly different. The high- and low-affinity binding constants for ¹²⁵I-EGF were calculated to be approximately 1 · 10¹² M^?1 and 2.5 · 10⁹ M^?1, respectively. Application of this technique in a competitive binding assay requires no more than 2.5 μg of membrane protein per assay, is essentially complete after 60 min, and facilitates screening of a large number of samples in a short time. Therefore, this will assist in the evaluation and quantitation of EGF and EGF-related transforming growth factor activity in physiological fluids. This technique may also be applied to analyses of other hormone-receptor systems.     

Growth factor receptors in helminth parasites: signalling and host-parasite relationships

Parasitic helminths remain major pathogens of both humans and animals throughout the world. The success of helminth infections depends on the capacity of the parasite to counteract host immune responses but also to exploit host-derived signal molecules for its development. Recent progress has been made in the characterization of growth factor receptors of various nematode and flatworm parasites with the demonstration that transforming growth factor beta (TGF-beta), epidermal growth factor (EGF) and insulin receptor signalling pathways are conserved in helminth parasites and potentially implicated in the host-parasite molecular dialogue and parasite development.     

Effect of cytokines, dexamethasone and the A/T-signal peptide polymorphism on the expression of alpha(1)-antichymotrypsin in astrocytes: significance for Alzheimer's disease

Proinflammatory cytokines and acute phase proteins, such as ₁-antichymotrypsin, are over expressed in microglia and astrocytes in brain regions with abundant mature amyloid plaques, suggesting a glial cell-led brain acute phase response in the Alzheimer neuropathology. In this paper, we show that ₁-antichymotrypsin gene expression in human astrocytes is elevated by interleukin-1 and interleukin-6, and further enhanced by glucocorticoid, while the homologous contrapsin gene in rat astrocytes is unaffected by these cytokines. These distinct gene regulation mechanisms might help to explain the differential susceptibility of humans and rodents to amyloid formation of the Alzheimer's type. In addition, we demonstrate that the ₁-antichymotrypsin A-allele that encodes a different signal peptide and is a suggested risk factor for Alzheimer's disease gives rise to a reduced level of immature ₁-antichymotrypsin in transfected cells. The physiological result would be an enhanced ability of the A-encoded ₁-antichymotrypsin protein to become secreted and promote extracellular amyloid formation. We discuss our findings in terms of a model in which cytokine-induced ₁-antichymotrypsin synthesis in astrocytes constitutes a specific inflammatory pathway that accelerates the development of Alzheimer's disease and could at least partly underlie the regional specificity and species restriction of the neuropathology.     

Association of physical activity and polymorphisms in FGFR2 and DNA methylation related genes with breast cancer risk

PurposePhysical activity, a protective factor for breast cancer, increases the level of DNA methylation. Fibroblast growth factor receptor 2 (FGFR2), a confirmed breast cancer susceptibility gene, is predisposed to be methylated. Therefore, DNA methylation related genes, such as methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR), and DNA methyltransferase (DNMT), together with physical activity and FGFR2, may interact with each other to effect breast cancer risk.MethodsA total of 839 incident breast cancer cases and 863 age-matched controls from Guangzhou, China were included in this study. We used questionnaires to assess physical activity in metabolic equivalent (MET)-h/week/year and a matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry platform to ascertain genotypes. Odds ratios (OR) and 95% confidence intervals (CI) were calculated from logistic regression models.ResultsExercise activity and FGFR2 rs2981582 were confirmed to be associated with breast cancer risk, and were found to significantly interact (P for multiplicative and additive interactions = 0.045 and 0.021, respectively). Women who had CT/TT genotypes of FGFR2 rs2981582 and experienced exercise activity <3 MET-h/week/year had significantly increased risk (OR = 3.15, 95% CI = 2.28–4.35) compared to women with CC genotype and ≥3 MET-h/week/year. There was also a significant interaction between FGFR2 rs2981582 and MTHFR rs1801133 on breast cancer risk (P for multiplicative and additive interactions = 0.039 and 0.023, respectively).ConclusionWe found both a gene–environment (FGFR2-exercise activity) and a gene–gene (FGFR2–MTHFR) interaction on breast cancer risk. Our results suggest that environmental factors, such as physical activity, may be able to counteract genetic susceptibility to breast cancer.     

Effect of cytokines, dexamethazone and the A/T-signal peptide polymorphism on the expression of alpha1-antichymotrypsin in astrocytes: significance for Alzheimer's disease

Proinflammatory cytokines and acute phase proteins, such as α₁-antichymotrypsin, are over expressed in microglia and astrocytes in brain regions with abundant mature amyloid plaques, suggesting a glial cell-led brain acute phase response in the Alzheimer neuropathology. In this paper, we show that α₁-antichymotrypsin gene expression in human astrocytes is elevated by interleukin-1 and interleukin-6, and further enhanced by glucocorticoid, while the homologous contrapsin gene in rat astrocytes is unaffected by these cytokines. These distinct gene regulation mechanisms might help to explain the differential susceptibility of humans and rodents to amyloid formation of the Alzheimer's type. In addition, we demonstrate that the α₁-antichymotrypsin A-allele that encodes a different signal peptide and is a suggested risk factor for Alzheimer's disease gives rise to a reduced level of immature α₁-antichymotrypsin in transfected cells. The physiological result would be an enhanced ability of the A-encoded α₁-antichymotrypsin protein to become secreted and promote extracellular amyloid formation. We discuss our findings in terms of a model in which cytokine-induced α₁-antichymotrypsin synthesis in astrocytes constitutes a specific inflammatory pathway that accelerates the development of Alzheimer's disease and could at least partly underlie the regional specificity and species restriction of the neuropathology.