Olfactory ensheathing cells promote proliferation and inhibit neuronal differentiation of neural progenitor cells through activation of Notch signaling

A population of neural progenitor cells (NPCs) has been known to exist in adult spinal cord and migrate toward the lesion regions during spinal cord injury (SCI). Although there are some positive effects of the transplanted olfactory ensheathing cells (OECs) on axonal regeneration in SCI, little is known about the effects and the underlying mechanism of these grafted OECs on NPCs. In this study, we have investigated how soluble factors derived from rat OECs regulate the proliferation and differentiation of rat NPCs. The conditioned medium from cultured OECs showed its ability to promote proliferation and inhibit neuronal differentiation of NPCs. Notch signaling was apparently involved in this process. With the addition of DAPT, which inhibited Notch signaling, the effects of OEC-conditioned medium on NPCs were blocked. We thus conclude that diffusible factors released from OECs activate the Notch signaling pathway to stimulate the proliferation and suppress neuronal differentiation of NPCs. These findings reveal the likely limitation of using OECs transplantation for SCI repair.

VEGF: an essential mediator of both angiogenesis and endochondral ossification

During bone growth, development, and remodeling, angiogenesis as well as osteogenesis are closely associated processes, sharing some essential mediators. Vascular endothelial growth factor (VEGF) was initially recognized as the best-characterized endothelial-specific growth factor, which increased vascular permeability and angiogenesis, and it is now apparent that this cytokine regulates multiple biological functions in the endochondral ossification of mandibular condylar growth, as well as long bone formation. The complexity of VEGF biology is paralleled by the emerging complexity of interactions between VEGF ligands and their receptors. This narrative review summarizes the family of VEGF-related molecules, including 7 mammalian members, namely, VEGF, placenta growth factor (PLGF), and VEGF-B, -C, -D, -E, and -F. The biological functions of VEGF are mediated by at least 3 corresponding receptors: VEGFR-1/Flt-1, VEGFR-2/Flk-1, VEGFR-3/Flt-4 and 2 co-receptors of neuropilin (NRP) and heparan sulfate proteoglycans (HSPGs). Current findings on endochondral ossification are also discussed, with emphasis on VEGF-A action in osteoblasts, chondroblasts, and chondroclasts/osteoclasts and regulatory mechanisms involving oxygen tension, and some growth factors and hormones. Furthermore, the therapeutic implications of recombinant VEGF-A protein therapy and VEGF-A gene therapy are evaluated. Abbreviations used: VEGF, Vascular endothelial growth factor; PLGF, placenta growth factor; NRP, neuropilin; HSPGs, heparan sulfate proteoglycans; FGF, fibroblast growth factor; TGF, transforming growth factor; HGF, hepatocyte growth factor; TNF, tumor necrosis factor; ECM, extracellular matrix; RTKs, receptor tyrosine kinases; ERK, extracellular signal kinases; HIF, hypoxia-inducible factor.

Recombinant AAV-mediated VEGF gene therapy induces mandibular condylar growth

Craniofacial anomalies resulting from impaired growth of mandibular condyles require multidisciplinary interventions, which impose a substantial burden on patients and their families. So far, correcting such deformities with an alternative strategy - gene therapy - is still an uncharted territory. Here, we established an effective in vivo gene delivery system with recombinant adeno-associated virus (rAAV)-mediated vascular endothelial growth factor (VEGF) to enhance mandibular condylar growth. With in situ hybridization, RT-PCR, immunostaining and Western blot, transgene expression was clearly detected in the mandibular condyles during the whole experiment periods. At defined time points, specific osteogenetic markers (alkaline phosphatase and osteocalcin) and chondrogenetic markers (collagen type II and collagen type X) were assessed by means of biochemical analysis and their expression significantly changed from day 30. Proliferation index by proliferating cell nuclear antigen staining showed also a significant increase in cell proliferation. Morphological measurement identified that the size of mandibular condyle significantly increased from day 30. Taken together, rAAV-VEGF was successfully established as an efficient delivery system to induce mandibular condylar growth, which provides the basis for future gene therapy to treat patients with craniofacial deformities.

A study on Notch signaling in human breast cancer

Breast cancer is one of the leading causes of cancer death in women. The Notch family of proteins plays crucial roles in determining cell fates such as proliferation, differentiation and apoptosis. A role for Notch signaling in human breast cancer has been suggested by the development of adenocarcinomas in the murine mammary gland. However, it is not clear currently whether Notch signaling is frequently expressed and activated in breast cancers. Here we show that Notch signaling is overexpressed and highly activated in breast cancers. More significantly, the attenuation of Notch signaling by gamma-secretase inhibitor can inhibit the proliferation of breast cancer cells by both causing cell cycle arrest and apoptosis. Thus, targeting Notch signaling may be of therapeutic value in breast cancers.

Identification of three FGA mutations in two Chinese families with congenital afibrinogenaemia

Congenital afibrinogenaemia is a rare autosomal recessive disorder, characterized by the complete absence or extremely reduced level of fibrinogen (Fg). We attempted to analyse the phenotype and genotype in two Chinese families with congenital afibrinogenaemia. Coagulation studies including activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) and Fg were performed in the patients and other family members. All the exons, exon-intron boundaries and promoter regions of three Fg genes (FGA, FGB and FGG) were screened by direct sequencing. Three patients in two families suffered from moderate to severe haemorrhage. Their APTT, PT and TT were extremely prolonged and plasma Fg levels were undetectable by Clauss method and extremely reduced by immunoassay. Genetic analysis revealed three FGA mutations in three patients including one novel mutation. In family 1, patient 1 was detected compound heterozygous mutations in FGA, g.1892-1899delAGTA/GTAA from her patriline and g.1978-g.3215del1238 bp from her matriline. In family 2, a homozygous Gln203X in Aalpha-chain was found in both patients 2 and 3 due to consanguineous marriage. All these mutations were null mutations, which could produce premature stop codons in FGA. It can be indicated that with more genetic analysis performed on afibrinogenaemia patients all over the world, there is no distinct difference in geographical distribution of Fg gene mutations. Gln203X in Aalpha-chain was first reported in this study, which may help to further understand the function of Aalpha-chain.

Female hemophilia A heterozygous for a de novo frameshift and a novel missense mutation of factor VIII

BACKGROUND

Hemophilia A (HA) is an X-chromosome-linked recessive disorder.

AIM

We report the case of a female HA patient with a moderate decrease of factor (F) VIII activity and antigen (FVIII:C 3.4%, FVIII:Ag 4.2%) and severe bleeding symptoms.

METHODS

The patient's father had mild FVIII deficiency (FVIII:C 6.9%, FVIII:Ag 7.4%), and her mother had normal FVIII activity. The von Willebrand disease antigen and von Willebrand factor ristocetin cofactor activity were normal in all family members. The genomic DNA was extracted from the peripheral blood lymphocytes of the patient and her family members. Long-distance polymerase chain reaction (PCR) was employed to screen for the intron 22 inversion of the FVIII coding gene (F8). The F8 coding sequence was amplified with PCR and sequenced with an automatic sequencer.

RESULTS

Two heterozygous mutations were identified in the patient: one a substitution of nucleotide 5981T by C that leads to a missense mutation Leu1975Pro, and the other an insertion of an 'A' between nucleotides 3,637 and 3,638 (3637_3638insA) that shifts the reading frame and predicts a premature stop codon downward. The mutation Leu1975Pro was identified in the father's F8; however, 3637_3638insA was a de novo mutation that occurred in the patient's maternal-derived F8. Real-time PCR was applied to analyze the level of ectopically F8 gene transcripts in the peripheral lymphocytes of family members. The ectopic transcripts of F8 of the patient were less abundant than the normal control (patient:normal control ratio 0.67), whereas her parents showed no significant difference from the normal control.

CONCLUSION

The FVIII deficiency of the HA patient resulted from a de novo occurrence of a frameshift 3637_3638insA in her maternal-derived F8 and a novel missense mutation Leu1975Pro inherited from her father.

Transient transcriptional response to low-dose ionizing radiation in humans undergoing IMRT

20018

Background: As intensity modulated radiation therapy techniques are increasingly utilized to treat cancer, the area of normal tissue exposed to ionizing radiation is increasing. The biologic risks associated with this normal tissue low dose exposure (LDIR) are fundamentally unknown and of concern to cancer survivors following therapy. Current modeling for health regulations presupposes a linear, no-threshold model of radiation effects, which estimates the effect and risk at low dose by extrapolation from measured effects at high doses. Cell culture models of ionizing radiation (RT) exposure show variable effects, not consistent with a linear dose-response relationship. We therefore undertook the first study to our knowledge of transcriptional effects of LDIR over time in vivo in solid tissue in humans. Methods: Tissue was collected at pre-RT, 3, 8, and 24 hours post-IR at sites receiving 10cGy. Transcriptional response at 3 and 8 hours were compared to the 0 and 24 hour time points. If transcripts are up regulated or down regulated at 3 and 8 hours compared with 0 and 24 hours, we have detected a transient response. The method of Rocke (2005), which was designed to detect differentially expressed gene groups using the responses of multiple probe sets corresponding to gene groups, was used to allow us to test whether there is differential expression for each patient separately, as well as for all the patients together. Results: Significant (p < 0.05) transient up regulation was shown in zinc finger proteins, keratins, BMP receptors, BAG, cyclins and BCL 6. Down regulation was detected in TNF, protein disulfide isomerase, interleukins, heat shock proteins, and S100. Nine gene groups did not show significant change; however, the number of significant gene groups (11) far exceeds the number expected by chance (2). In most cases in which a gene group was shown to be transiently altered, the tests of individual patients showed that most or all of the individuals also had differential expression of the same type. Conclusions: We have shown that it is possible to detect transient responses to LDIR in vivo in humans, and have identified eleven gene groups that demonstrate transient changes, as measured by a statistically principled analysis method.

No significant financial relationships to disclose.

Biotransformation of alpha- and 6beta-santonin by fungus and plant cell cultures

One fungus, Abisidia coerulea IFO 4011, and suspended cell cultures of one plant, Asparagus officinalis, were employed to bioconvert alpha- and 6beta-santonin. Incubation of alpha-santonin with the cell cultures of the fungus afforded two products, 11beta-hydroxy-alpha-santonin (1, in 76.5% yield) and 8alpha-hydroxy-alpha-santonin (2, in 2.0% yield). And from 6beta-santonin, four major products (3, 4, 5 and 6) and four minor products (7, 8, 9 and 10) were obtained, including 8alpha-hydroxylated products in trace yields. Very interestingly, a skeletal rearrangement occurred and a guaiane product (13) formed in a very low yield when alpha-santonin incubating with A.officinalis cell cultures, while not in the case of 6beta-santonin as substrate. Among the obtained 15 products, 2, 7, 8, 9, 10 and 12 are new compounds. The fact of 8alpha hydroxylation of santonin enables the formation of 8,12-eudesmanolide instead of 6,12-eudesmanolide and some useful modification at C-8 position. In addition, these reactions would provide evidence for the biogenesis between different types of eudesmane and/or guaiane compounds in the plants in nature.

Two-electron linear intersubband light absorption in a biased quantum well

We point out a novel manifestation of many-body correlations in the linear optical response of electrons confined in a quantum well. Namely, we demonstrate that along with the conventional absorption peak at a frequency omega close to the intersubband energy delta, there exists an additional peak at frequency h omega approximately = 2delta. This new peak is solely due to electron-electron interactions, and can be understood as excitation of two electrons by a single photon. The actual peak line shape is comprised of a sharp feature, due to excitation of pairs of intersubband plasmons, on top of a broader band due to absorption by two single-particle excitations. The two-plasmon contribution allows us to infer intersubband plasmon dispersion from linear absorption experiments.

A rapid multifluorescent polymerase chain reaction for genetic counselling in Chinese haemophilia A families

Linkage analysis is a widely used strategy for genetic counselling in haemophilia A (HA) families. We attempted to develop more informative markers closely linked to factor VIII (FVIII) gene and establish a rapid multifluorescent polymerase chain reaction (PCR) method with these markers. Five extragenic (DXS15, DXS9901, G6PD, DXS1073 and DXS1108) and one intragenic (F8Civs13) markers were examined in 118 healthy individuals and 12 HA families which had been diagnosed before. Five extragenic markers were within an interval of about 1.5 Mb to FVIII gene and located on each side of the gene. The expected heterozygote rate (HR) of DXS15, DXS9901, G6PD, DXS1073, DXS1108 and F8Civs13 were 74.97%, 79.77%, 56.06%, 59.92%, 39.97% and 47.61%, while the observed HR were 88.24%, 82.35%, 21.57%, 62.75%, 35.29% and 52.94%. When six polymorphic markers were combined together, all the studied females were informative in at least one of these markers and 29.41% of them were detected informative in three markers with the highest frequency. The diagnostic rates of DXS15, DXS9901, G6PD, DXS1073, DXS1108 and F8Civs13 in 12 haemophilia families were 75.00%, 91.67%, 41.67%, 75.00%, 33.33% and 66.67% respectively. All the genetic diagnosis was consistent with the result we analysed before and no recombination was observed. Family 1 was given as an example in this study and was found to be informative in three polymorphic markers DXS15, DXS9901 and DXS1073. The patient's sister was detected the same allele as the proband, but her male fetus did not inherit the affected allele from her, which was consistent with the result of sequencing. It was demonstrated that the multifluorescent PCR method established in this study was convenient and efficient and can be applied to carrier detection and prenatal diagnosis in HA families.

Transfection of Smac sensitizes tumor cells to etoposide-induced apoptosis and eradicates established human hepatoma in vivo

A major concern in clinical treatment of cancers is resistance of tumors such as hepatocellular carcinoma (HCC) and osteosarcoma to current chemotherapy protocols. Here, we reported that overexpression of second mitochondria-derived activator of caspase (Smac) sensitized osteosarcoma cells and HCC cells in vitro to chemotherapeutic drugs-induced apoptosis. Constitutive expression of Smac resulted in enhanced Bax accumulation on mitochondria upon etoposide stimulation and inhibited Bcl-2-induced antiapoptosis activity. Thus, Smac would sensitize tumor cells to chemotherapeutic drugs in part through promoting Bax translocation to mitochondria and bypassing Bcl-2 block. Moreover, we demonstrated that blockade of Smac expression by antisense smac did not impair etoposide-induced apoptosis; however, p53-induced apoptosis was impaired in smac deficient Saos-2 cell. This suggested Smac might be required in p53-induced apoptosis. Most importantly, complete eradication of HepG2 xenografts in vivo was achieved upon combined therapy with Ad-Smac and 5-Fu. Thus, overexpression of Smac in tumor cells might be a potent strategy for cancer treatment by sensitization of tumor cells to chemotherapeutic drugs.

[Cloning and characterization of a novel mouse short-chain dehydrogenase/reductases cDNA mHsdl2#, encoding a protein with a SDR domaid and a SCP2 domain]

The short-chain dehydrogenases/reductases (SDRs) play important roles in body's metabolism. We cloned a novel mouse SDR cDNA which encodes a deduced HSD-like protein with a conserved SDR domain and a SCP2 domain. The 1.8 kb cDNA consists of 11 exons and is mapped to mouse chromosome 4B3. The corresponding gene is widely expressed in normal mouse tissues and its expression level in liver increases after inducement with cholesterol food. The predicted mouse HSDL2 protein, which has a peroxisomal target signal, is localized in the cytoplasm of NIH 3T3 cells.

Regression of NMU-induced mammary tumors with the combination of melatonin and 9-cis-retinoic acid

A significant increase in tumor regression was induced in N-nitroso-N-methylurea-induced mammary tumors in rats treated with the combination of melatonin and 9-cis-retinoic acid (9cRA). Treatment groups included: control (ethanolic saline), 9cRA (30 mg/kg chow/day), melatonin 500 microg/day, melatonin 1000 microg/day, melatonin 500 microg/day+9cRA and melatonin 1000 microg/day+9cRA. Rats treated with the lower dose of melatonin 500 microg+9cRA show the greatest degree of tumor regression (78%), with 54% undergoing complete regression and a significant increase in apoptotic cells observed by TUNEL Assay. Furthermore, tumor multiplicity and burden were significantly decreased by the combination of melatonin and 9cRA.