Calcium mimics the chemotactic effect of conditioned media and is an effective inducer of bone regeneration

Background

After bone resorption, ions and degraded organic components are co-released into the extracellular space. Ions and growth factors, although different in their biological nature, induce a common and coordinated chemotactic effect. Conditioned media has been used successfully in bone regeneration by promoting endogenous cell recruitment. Likewise, calcium alone act as a paracrine chemotactic signal, inducing the host’s undifferentiated progenitor cell infiltration into the implanted biomaterials. The aim of the present study was to compare the chemotactic effect of calcium and conditioned media in primary calvarial cells.

Methods

The chemotactic cell response was evaluated in vitro using an agarose spot and a wound healing assay. In addition, we used a calvarial bone explant model ex-vivo. The healing potential was also tested through an in vivo model, a critical-size calvarial bone defect in mice. For the in vivo experiment, cell-free calcium-containing or conditioned media-containing scaffolds were implanted, and MSC’s seeded scaffolds were used as positive control. After seven weeks post-implantation, samples were retrieved, and bone regeneration was evaluated by μCT and histological analysis. Osteogenic gene expression was evaluated by qPCR.

Results

We found that chemotactic cell migration in response to either calcium or conditioned media was equivalent in vitro and ex vivo. Accordingly, μCT analysis showed that bone regeneration induced by the MSC’s seeded scaffolds was similar to that obtained with cell-free calcium or conditioned media-containing scaffolds. Pre-treatment with SB202190, a highly selective p38 inhibitor, abrogated the chemotactic effect induced by conditioned media. In contrast, p38 activity was not essential for the calcium-induced chemotaxis. Moreover, BAPTA-AM treatment, a cytosolic calcium chelator, decreased the chemotactic effect and the expression of key osteogenic genes induced by calcium or conditioned media.

Conclusion

We show that calcium ions alone not only mimic the conditioned media chemotactic effect, but also induce an osteogenic effect similar to that produced by transplanted MSC’s in vivo. Furthermore, the chemotactic effect induced by conditioned media is calcium and p38 dependent. The rise in cytosolic calcium might integrate the different signaling pathways triggered by conditioned media and extracellular Ca²⁺. This calcium-driven in situ bone regeneration is a promising and convenient alternative to promote endogenous cell recruitment into the injured bone site. This pre-clinical cell-free and growth factor-free approach might avoid the disadvantages of the ex vivo cell manipulation.

Microparticles Produced by Activated Platelets Carry a Potent and Functionally Active Angiogenic Signal in Subjects with Crohn's Disease

Microparticles (MPs) are submicron vesicles shed from various cell types upon activation, stimulation, and death. Activated platelets are an important source of circulating MPs in subjects with inflammatory diseases, including Crohn’s disease (CD). Angiogenesis is a hallmark of inflammation in CD and plays an active role in sustaining disease progression, while targeting angiogenesis may be an effective approach to block colitis. In this study, we analyzed the angiogenic content of the MPs produced by activated platelets in subjects with CD. We also evaluated whether the angiogenic signal carried by these MPs was functionally active, or able to induce angiogenesis. We found that, in subjects with CD, MPs produced by activated platelets contain significantly higher levels of angiogenic mRNAs, such as epidermal growth factor (EGF), platelet-derived growth factor-α (PDGFα), fibroblast growth factor (FGF-2), and angiopoietin-1 (ANGPT1), compared to MPs isolated from control subjects. They also contain significantly higher levels of prototypical angiogenic proteins, including vascular endothelial growth factor (VEGF), angiopoietin-1, endoglin, endothelin-1, pentraxin 3, platelet factor-4, plasminogen activator inhibitor-1 (PAI-1), tissue inhibitor of metalloproteinases-1 (TIMP-1), and thrombospondin 1. The protein content of these MPs is functionally active, since it has the ability to induce a robust angiogenic process in an endothelial cell/interstitial cell co-culture in vitro assay. Our results reveal a potential novel mechanism through which the angiogenic signal is delivered in subjects with CD, with potentially important clinical and therapeutic implications.

Role of the composite glucocorticoid response element in proliferin gene expression

A binding site for the glucocorticoid receptor in the serum-inducible proliferin gene promoter has been reported to function as a composite glucocorticoid response element when fused to a minimal promoter. We now show that this element can also act as a glucocorticoid-independent negative regulator of transcription, both as an isolated element fused to a minimal promoter and within the context of the proliferin gene promoter. Furthermore, this element is recognized by a factor in mouse fibroblast cell extracts that is distinct from the glucocorticoid receptor and from AP-1, both of which have previously been shown to be able to bind to this site. The ability of this element to repress serum-inducible proliferin promoter activity is dependent on the position of this element with respect to the adjacent serum response region, and on the activity of a positive regulatory element located further upstream in the proliferin promoter.

Hormone induced differential transcriptome analysis of Sertoli cells during postnatal maturation of rat testes

Sertoli cells (Sc) are unique somatic cells of testis that are the target of both FSH and testosterone (T) and regulate spermatogenesis. Although Sc of neonatal rat testes are exposed to high levels of FSH and T, robust differentiation of spermatogonial cells becomes conspicuous only after 11-days of postnatal age. We have demonstrated earlier that a developmental switch in terms of hormonal responsiveness occurs in rat Sc at around 12 days of postnatal age during the rapid transition of spermatogonia A to B. Therefore, such “functional maturation” of Sc, during pubertal development becomes prerequisite for the onset of spermatogenesis. However, a conspicuous difference in robust hormone (both T and FSH) induced gene expression during the different phases of Sc maturation restricts our understanding about molecular events necessary for the spermatogenic onset and maintenance. Here, using microarray technology, we for the first time have compared the differential transcriptional profile of Sc isolated and cultured from immature (5 days old), maturing (12 days old) and mature (60 days old) rat testes. Our data revealed that immature Sc express genes involved in cellular growth, metabolism, chemokines, cell division, MAPK and Wnt pathways, while mature Sc are more specialized expressing genes involved in glucose metabolism, phagocytosis, insulin signaling and cytoskeleton structuring. Taken together, this differential transcriptome data provide an important resource to reveal the molecular network of Sc maturation which is necessary to govern male germ cell differentiation, hence, will improve our current understanding of the etiology of some forms of idiopathic male infertility.

Human Serum for Culture of Articular Chondrocytes

In the field of cell and tissue engineering, culture expansion of human cells in monolayer plays an important part. Traditionally, cell cultures have been supplemented with serum to support attachment and proliferation, but serum is a potential source of foreign protein contamination and viral protein transmission. In this study, we evaluated the use of human serum for experimental human articular chondrocyte expansion and to develop a method for preparation of large volumes of high-quality human serum from healthy blood donors. Human autologous serum contained high levels of epidermal-derived growth factor and platelet-derived growth factor-AB and supported proliferation up to 7 times higher than FCS in primary chondrocyte cultures. By letting the coagulation take place in a commercially available transfusion bag overnight, up to 250 ml of growth factor-rich human serum could be obtained from one donor. The allogenic human serum supported high proliferation rate without loosing expression of cartilage-specific genes. The expanded chondrocytes were able to redifferentiate and form cartilage matrix in comparable amounts to autologous serums. In conclusion, the transfusion bags allow preparation of large volumes of growth factor-rich human serum with the capacity to support in vitro cell expansion. The data further indicate that by controlling the coagulation process there are possibilities of optimizing the release of growth factors for other emerging cell therapies.

In Vivo Evaluation of Pharmacologically Active Microcarriers Releasing Nerve Growth Factor and Conveying PC12 Cells

Cell therapy will probably become a major therapeutic strategy in the coming years. Nevertheless, few cells survive transplantation when employed as a treatment for neuronal disorders. To address this problem, we have developed a new tool, the pharmacologically active microcarriers (PAM). PAM are biocompatible and biodegradable microparticles coated with cell adhesion molecules, conveying cells on their surface and presenting a controlled delivery of growth factor. Thus, the combined effect of growth factor and coating influences the transported cells by promoting their survival and differentiation and favoring their integration in the host tissue after their complete degradation. Furthermore, the released factor may also influence the microenvironment. In this study, we evaluated their efficacy using nerve growth factor (NGF)-releasing PAM and PC12 cells, in a Parkinson's disease paradigm. After implantation of NGF-releasing or unloaded PAM conveying PC12 cells, or PC12 cells alone, we studied cell survival, differentiation, and apoptosis, as well as behavior of the treated rats. We observed that the NGF-releasing PAM coated with two synthetic peptides (poly-D-lysine and fibronectin-like) induced PC12 cell differentiation and reduced cell death and proliferation. Moreover, the animals receiving this implant presented an improved amphetamine-induced rotational behavior. These findings indicate that PAM could be a promising strategy for cell therapy of neurological diseases and could be employed in other situations with fetal cell transplants or with stem cells.

The Adaptive Remodeling of Condylar Cartilage— A Transition from Chondrogenesis to Osteogenesis

Mandibular condylar cartilage is categorized as articular cartilage but markedly distinguishes itself in many biological aspects, such as its embryonic origin, ontogenetic development, post-natal growth mode, and histological structures. The most marked uniqueness of condylar cartilage lies in its capability of adaptive remodeling in response to external stimuli during or after natural growth. The adaptation of condylar cartilage to mandibular forward positioning constitutes the fundamental rationale for orthodontic functional therapy, which partially contributes to the correction of jaw discrepancies by achieving mandibular growth modification. The adaptive remodeling of condylar cartilage proceeds with the biomolecular pathway initiating from chondrogenesis and finalizing with osteogenesis. During condylar adaptation, chondrogenesis is activated when the external stimuli, e.g., condylar repositioning, generate the differentiation of mesenchymal cells in the articular layer of cartilage into chondrocytes, which proliferate and then progressively mature into hypertrophic cells. The expression of regulatory growth factors, which govern and control phenotypic conversions of chondrocytes during chondrogenesis, increases during adaptive remodeling to enhance the transition from chondrogenesis into osteogenesis, a process in which hypertrophic chondrocytes and matrices degrade and are replaced by bone. The transition is also sustained by increased neovascularization, which brings in osteoblasts that finally result in new bone formation beneath the degraded cartilage.

Ontogeny of Vascular Growth Factors in Perinatal Sheep Myocardium

OBJECTIVE

To examine developmental changes in myocardial gene expression of previously identified regulators of vascular growth.

METHODS

Ovine left (LV) and right ventricle (RV) samples were obtained at four time points: 95 days' and 140 days' gestation (term = 145 days) and 7 days and 8 weeks postnatally. mRNA and protein levels of vascular endothelial growth factor (VEGF), its respective receptors (Flk-1 and Flt-1), basic fibroblast growth factor (bFGF), transforming growth factor-beta1 (TGF-beta1), and endothelial nitric oxide synthase (eNOS) were measured at these different time points.

RESULTS

RV but not LV VEGF mRNA levels decreased postnatally, although VEGF protein expression remained unchanged after birth. Flt-1 mRNA expression was divergent between ventricles, although the protein expression pattern was similar in RV and LV, decreasing with maturation. RV and LV Flk-1 mRNA decreased between 95 days and 140 days, remaining stable thereafter, while protein levels only decreased after birth. bFGF protein levels were highest in the LV at 140 days, and decreased after birth but remained unchanged in the RV throughout the period examined. TGF-beta1 and eNOS levels were highest early in gestation, decreasing with maturation in both ventricles.

CONCLUSION

Developmentally regulated ventricle-specific expression of VEGF, Flt-1, Flk-1, TGF-beta1, bFGF, and eNOS was demonstrated in the ovine myocardium. These findings suggest these proteins may participate in coronary vascular remodeling during the perinatal period and underscore the importance of studying the relationships among transcription factors, target genes, and anatomic/physiologic changes in the whole animal.

Current siRNA targets in the prevention and treatment of intimal hyperplasia

Intimal hyperplasia (IH) is the leading cause of late vein and prosthetic bypass graft failure. Injury at the time of graft implantation leading to the activation of endothelial cells and dedifferentiation of vascular smooth muscle cells to a synthetic phenotype are known causes of IH. Prior attempts to develop therapy to mitigate these cellular changes to prevent IH and graft failure have failed. Small interfering RNA (siRNA) mediated targeted gene silencing is a promising tool to prevent IH. Several studies have been performed in this direction to target genes that are involved in IH. In this review we discuss siRNA targets that are being investigated for prevention and treatment of IH.

Trefoil factor 1 gene alternations and expression in colorectal carcinomas

AIMS AND BACKGROUND

Aberrant expression of the trefoil factor family (TFF) has been recognized to be involved in the development and/or progression of various solid tumors. Increased trefoil factor 1 (TFF1) expression is found associated with tumor progression in some tumors, and TFF1 missense mutations have been detected in gastric cancer. The aim of the study was to analyze TFF1 alternations and expression in colorectal carcinoma and their correlation with cancer progression and pathological aspects.

METHODS

TFF1 mutations were detected in colorectal carcinomas by DNA sequencing. TFF1 mRNA and protein levels in subsets of the primary tumors were determined using quantitative reverse transcription polymerase chain reaction and immunohistochemistry analyses. The serum level of TFF1 was also detected by enzyme-linked immunosorbent assay for patients with colorectal carcinoma.

RESULTS

Five variants were detected in the 5'-untranslation region and intron 1 of TFF1. TFF1 expression was increased in colorectal carcinoma compared to paired distal colonic mucosa. Immunohistochemistry in primary colorectal carcinoma showed no significant differences in tumor TFF1 levels with respect to clinicopathological parameters such as the patient's sex, cancer differentiation, stage and lymph node metastasis. However, serum TFF1 levels were significantly elevated in patients with colorectal carcinoma compared to healthy individuals.

CONCLUSIONS

The results indicate that TFF1 missense mutations seem to be a rare event in colorectal carcinogenesis. Serum TFF1 may be a potential useful marker for patients with colorectal carcinoma.

PACAP and PAC1 receptor in brain development and behavior

Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) act through three class B G-protein coupled receptors, PAC1, VPAC1 and VPAC2, initiating multiple signaling pathways. In addition to natural peptides ligands, a number of synthetic peptides and a small molecular antagonist have been generated. Genetically modified animals have been produced for the neuropeptides and receptors. Neuroanatomical, electrophysiological, behavioral and pharmacological characterization of the mutants and transgenic mice uncovered diverse roles of PACAP-PAC1-VAPC2 signaling in peripheral tissues and in the central nervous system. Human genetic studies suggest that the PACAP-PAC1-VPAC2 signaling can be associated with psychiatric illness via mechanisms of not only loss-of-function, but also gain-of-function. For example, a duplication of chromosome 7q36.3 (encoding the VPAC2 receptor) was shown to be associated with schizophrenia, and high levels of PACAP-PAC1 signaling are associated with posttraumatic stress disorder. Whereas knockout animals are appropriate to address loss-of-function of human genetics, transgenic mice overexpressing human transgenes in native environment using artificial chromosomes are particularly valuable and essential to address the consequences of gain-of-function. This review focuses on role of PACAP and PAC1 receptor in brain development, behavior of animals and potential implication in human neurodevelopmental disorders. It also encourages keeping an open mind that alterations of VIP/PACAP signaling may associate with psychiatric illness without overt neuroanatomic changes, and that tuning of VIP/PACAP signaling may represent a novel avenue for the treatment of the psychiatric illness.

The capacity of connective tissue stromas to sustain myelopoiesis depends both upon the growth factors and the local intercellular environment

In adults, haemopoiesis is located in the bone marrow, where it is tightly regulated by cytokines and by a physical association of haemopoietic progenitors with the stroma. However, in pathological situations, haemopoiesis can be partly or fully dislodged to peripheral tissues. It is not clear which are the requirements for a given peripheral stroma to sustain haemopoiesis. Using the growth factor-dependent cell line FDC-P1, we have compared the myelopoietic capacities of a murine bone marrow-derived cell line S17, a liver inflammatory granuloma-derived stroma (GR) that sustains haemopoiesis, and normal skin fibroblasts (SF) that sustain neither survival nor proliferation of myeloid cells. All three stromas expressed mRNA for major haemopoietins with the exception of IL-3. Despite the incapacity of SF to sustain FDC-P1 cells, the biologically active GM-CSF could be recovered from all the studied stromas by treatment with high-salt buffers that release non-covalently bound molecules from stroma cells. Glycosaminoglycans purified from stromas had distinct effect on the GM-CSF-mediated proliferation of FDC-P1 cells: those purified from S17 and GR cells were stimulatory, whereas those obtained from SF cells were slightly stimulatory at low concentration, but inhibitory at the higher ones. We conclude that the quality of the stroma pericellular glycoconjugates is determinant for the ability of a given stroma to sustain myelopoiesis, even when biologically active haemopoietins are locally produced.

Gene expression profiling through microarray analysis in Arabidopsis thaliana colonized by Pseudomonas putida MTCC5279, a plant growth promoting rhizobacterium

Plant growth promotion is a multigenic process under the influence of many factors; therefore an understanding of these processes and the functions regulated may have profound implications. Present study reports microarray analysis of Arabidopsis thaliana plants inoculated with Pseudomonas putida MTCC5279 (MTCC5279) which resulted in significant increase in growth traits as compared with non-inoculated control. The gene expression changes, represented by oligonucleotide array (24652 genes) have been studied to gain insight into MTCC5279 assisted plant growth promotion in Arabidopsis thaliana. MTCC5279 induced upregulated Arabidopsis thaliana genes were found to be involved in maintenance of genome integrity (At5g20850), growth hormone (At3g23890 and At4g36110), amino acid synthesis (At5g63890), abcissic acid (ABA) signaling and ethylene suppression (At2g29090, At5g17850), Ca⁺² dependent signaling (At3g57530) and induction of induced systemic resistance (At2g46370, At2g44840). The genes At3g32920 and At2g15890 which are suggested to act early in petal, stamen and embryonic development are among the downregulated genes. We report for the first time MTCC5279 assisted repression of At3g32920, a putative DNA repair protein involved in recombination and DNA strand transfer in a process of rapid meiotic and mitotic division.

Maternal growth factor regulation of human placental development and fetal growth

Normal development and function of the placenta is critical to achieving a successful pregnancy, as normal fetal growth depends directly on the transfer of nutrients from mother to fetus via this organ. Recently, it has become apparent from both animal and human studies that growth factors within the maternal circulation, for example the IGFs, are important regulators of placental development and function. Although these factors act via distinct receptors to exert their effects, the downstream molecules activated upon ligand/receptor interaction are common to many growth factors. The expression of numerous signaling molecules is altered in the placentas from pregnancies affected by the fetal growth complications, fetal growth restriction, and macrosomia. Thus, targeting these molecules may lead to more effective treatments for complications of pregnancy associated with altered placental development. Here, we review the maternal growth factors required for placental development and discuss their mechanism of action.

Structural basis for the growth factor activity of human adenosine deaminase ADA2

Two distinct adenosine deaminases, ADA1 and ADA2, are found in humans. ADA1 has an important role in lymphocyte function and inherited mutations in ADA1 result in severe combined immunodeficiency. The recently isolated ADA2 belongs to the novel family of adenosine deaminase growth factors (ADGFs), which play an important role in tissue development. The crystal structures of ADA2 and ADA2 bound to a transition state analogue presented here reveal the structural basis of the catalytic/signaling activity of ADGF/ADA2 proteins. In addition to the catalytic domain, the structures discovered two ADGF/ADA2-specific domains of novel folds that mediate the protein dimerization and binding to the cell surface receptors. This complex architecture is in sharp contrast with that of monomeric single domain ADA1. An extensive glycosylation and the presence of a conserved disulfide bond and a signal peptide in ADA2 strongly suggest that ADA2, in contrast to ADA1, is specifically designed to act in the extracellular environment. The comparison of catalytic sites of ADA2 and ADA1 demonstrates large differences in the arrangement of the substrate-binding pockets. These structural differences explain the substrate and inhibitor specificity of adenosine deaminases and provide the basis for a rational design of ADA2-targeting drugs to modulate the immune system responses in pathophysiological conditions.

DNA methylation patterns of ulcer-healing genes associated with the normal gastric mucosa of gastric cancers

Recent evidence suggests that gastric mucosal injury induces adaptive changes in DNA methylation. In this study, the methylation status of the key tissue-specific genes in normal gastric mucosa of healthy individuals and cancer patients was evaluated. The methylation-variable sites of 14 genes, including ulcer-healing genes (TFF1, TFF2, CDH1, and PPARG), were chosen from the CpG-island margins or non-island CpGs near the transcription start sites. The healthy individuals as well as the normal gastric mucosa of 23 ulcer, 21 non-invasive cancer, and 53 cancer patients were examined by semiquantitative methylation-specific polymerase chain reaction (PCR) analysis. The ulcer-healing genes were concurrently methylated with other genes depending on the presence or absence of CpG-islands in the normal mucosa of healthy individuals. Both the TFF2 and PPARG genes were frequently undermethylated in ulcer patients. The over- or intermediate-methylated TFF2 and undermethylated PPARG genes was more common in stage-1 cancer patients (71%) than in healthy individuals (10%; odds ratio [OR], 21.9) and non-invasive cancer patients (21%; OR, 8.9). The TFF2-PPARG methylation pattern of cancer patients was stronger in the older-age group (> or =55 yr; OR, 43.6). These results suggest that the combined methylation pattern of ulcer-healing genes serves as a sensitive marker for predicting cancer-prone gastric mucosa.

Growth factors, muscle function, and doping

This article discusses the inevitable use of growth factors for enhancing muscle strength and athletic performance. Much effort has been expended on developing a treatment of muscle wasting associated with a range of diseases and aging. Frailty in the aging population is a major socioeconomic and medical problem. Emerging molecular techniques have made it possible to gain a better understanding of the growth factor genes and how they are activated by physical activity. The ways that misuse of growth factors may be detected and verified in athletes and future challenges for detecting manipulation of signaling pathways are discussed.

The small chromatin-binding protein p8 coordinates the association of anti-proliferative and pro-myogenic proteins at the myogenin promoter

Quiescent muscle progenitors called satellite cells persist in adult skeletal muscle and, upon injury to muscle, re-enter the cell cycle and either undergo self-renewal or differentiate to regenerate lost myofibers. Using synchronized cultures of C2C12 myoblasts to model these divergent programs, we show that p8 (also known as Nupr1), a G1-induced gene, negatively regulates the cell cycle and promotes myogenic differentiation. p8 is a small chromatin protein related to the high mobility group (HMG) family of architectural factors and binds to histone acetyltransferase p300 (p300, also known as CBP). We confirm this interaction and show that p300-dependent events (Myc expression, global histone acetylation and post-translational acetylation of the myogenic regulator MyoD) are all affected in p8-knockdown myoblasts, correlating with repression of MyoD target-gene expression and severely defective differentiation. We report two new partners for p8 that support a role in muscle-specific gene regulation: p68 (Ddx5), an RNA helicase reported to bind both p300 and MyoD, and MyoD itself. We show that, similar to MyoD and p300, p8 and p68 are located at the myogenin promoter, and that knockdown of p8 compromises chromatin association of all four proteins. Thus, p8 represents a new node in a chromatin regulatory network that coordinates myogenic differentiation with cell-cycle exit.

Modulation of Growth Factor Gene Expression in Vascular Cells by Oxidative Stress

Reactive oxygen species (ROS) generated in and around vascular endothelium may play a role in normal cellular signaling mechanisms but may also be an important causative factor in endothelial dysfunction underlying the development of atherosclerosis, diabetes complications, and ischemia-reperfusion injury. ROS influence a variety of molecular and cellular activities, including changes in the cellular localization of regulatory factors, protein modification, and altered gene expression, which in turn influence cellular phenotype. One mechanism by which ROS exert their cellular effects involves their ability to modulate the expression and function of vascular genes, such as vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and platelet-derived growth factor (PDGF), which play key atherogenic roles by their regulation of cell growth, differentiation, and fibroproliferative responsiveness. In this review the authors describe the changes induced by oxidative stress on the profile of growth factor gene expression in endothelial cells, and the impact these modifications have on endothelial phenotype as well as on the behavior of neighboring vascular smooth muscle cells and fibroblasts. The authors also discuss the involvement of redox-sensitive transcription factors in these regulatory processes.

Neuronal gene expression and function in the growth-stimulated R28 retinal precursor cell line

PURPOSE

Proliferative retinal progenitor cells that express neuronal characteristics are potentially useful for developmental studies and as experimental graft material. The continuously-growing R28 retinal cell line has been distributed to over 60 laboratories for a variety of studies, yet has not been fully characterized. In this study, we tested the hypothesis that the proliferative R28 retinal cell line contains subpopulations of cells that express neuronal mRNAs and proteins characteristic of CNS neurons.

METHODS

To this end, we sought to determine the potential retinal, neuronal, and growth-related characteristics of this retinal cell line through gene expression profiling, coupled with confirmatory immunocytochemistry and electrophysiology.

RESULTS

Despite expression of growth-stimulatory oncogenes and growth-promoting factors, subpopulations of R28 cells express abundant retinal and neuronal markers, as well as the functional capacity to respond to specific neurotransmitters such as dopamine, acetylcholine, serotonin, and glycine.

CONCLUSION

Proliferative R28 cells retain functional neuronal properties that may prove useful in future studies of neuronal differentiation and development.

Urotensin II is an autocrine/paracrine growth factor for aortic adventitia of rat

Urotensin II (UII) is a potent vasoconstrictive peptide; however, its significance in vascular adventitia has not been clearly elucidated. In this study, rat aortic adventitia showed mRNA expression and immunoreactivity of UII and its receptor (UT). Moreover, radioligand-binding assay showed that maximum binding capacity (Bmax) of [(125)I]-UII was higher in adventitia than in media (28.60+/-1.94 vs. 20.21+/-1.11 fmol/mg, P<0.01), with no difference in binding affinity (dissociation constant [Kd] 4.27+/-0.49 vs. 4.60+/-0.40 nM, P>0.05). Furthermore, in cultured adventitial fibroblasts, UII stimulated DNA synthesis, collagen synthesis and secretion in a concentration-dependent manner. These effects were inhibited by the UII receptor antagonist urantide (10(-6) mol/l), Ca(2+) channel blocker nicardipine (10(-5) mol/l), protein kinase C inhibitor H7 (10(-6) mol/l), and mitogen-activated protein kinase inhibitor PD98059 (10(-6) mol/l) but not the phosphatidyl inositol-3 kinase inhibitor wortmannin (10(-7) mol/l). UII may act as an autocrine/paracrine factor through its receptor and the Ca(2+) channel, protein kinase C, and mitogen-activated protein kinase signal transduction pathways, in the pathogenesis of vascular remodeling by activating vascular adventitia.

Gene expression and functional studies of the optic nerve head astrocyte transcriptome from normal African Americans and Caucasian Americans donors

Purpose

To determine whether optic nerve head (ONH) astrocytes, a key cellular component of glaucomatous neuropathy, exhibit differential gene expression in primary cultures of astrocytes from normal African American (AA) donors compared to astrocytes from normal Caucasian American (CA) donors.

Methods

We used oligonucleotide Affymetrix microarray (HG U133A & HG U133A 2.0 chips) to compare gene expression levels in cultured ONH astrocytes from twelve CA and twelve AA normal age matched donor eyes. Chips were normalized with Robust Microarray Analysis (RMA) in R using Bioconductor. Significant differential gene expression levels were detected using mixed effects modeling and Statistical Analysis of Microarray (SAM). Functional analysis and Gene Ontology were used to classify differentially expressed genes. Differential gene expression was validated by quantitative real time RT-PCR. Protein levels were detected by Western blots and ELISA. Cell adhesion and migration assays tested physiological responses. Glutathione (GSH) assay detected levels of intracellular GSH.

Results

Multiple analyses selected 87 genes differentially expressed between normal AA and CA (P<0.01). The most relevant genes expressed in AA were categorized by function, including: signal transduction, response to stress, ECM genes, migration and cell adhesion.

Conclusions

These data show that normal astrocytes from AA and CA normal donors display distinct expression profiles that impact astrocyte functions in the ONH. Our data suggests that differences in gene expression in ONH astrocytes may be specific to the development and/or progression of glaucoma in AA.

Gene expression profiling during early folliculogenesis in the mouse ovary

OBJECTIVE

To evaluate genes involved in ovarian primordial-to-primary follicle transition.

DESIGN

Experimental animal study.

SETTING

Research institute.

ANIMAL(S)

Day-2 and day-4 female Swiss mice.

INTERVENTION(S)

We conducted a complementary DNA array study using ovarian messenger RNAs from day-2 and day-4 mice.

MAIN OUTCOME MEASURE(S)

The expression profiles of 1,176 genes in neonatal mouse ovaries on day 2 and day 4, which contain primordial and primary follicles, respectively, were compared.

RESULT(S)

Twenty-six percent of genes were differentially expressed between day-2 and day-4 ovaries, with 19% being up-regulated and 7% down-regulated in day 4. Analysis of differentially expressed genes revealed that the primordial-to-primary follicle stage transition is associated with induction in the expression of mainly growth factors, immune-related factors, hormone and hormone receptors, and signal transducers. The transition is also associated with proliferation of granulosa cells and absence of apoptosis. In addition, our studies demonstrated that the primary follicles express estrogen receptor beta and are responsive to estrogen actions in vitro in terms of increase in the number of primary follicles and granulosa cell proliferation.

CONCLUSION(S)

The transition of primordial to primary follicles is associated with the participation of multiple pathways in regulating gene expression.

Mitogenic functions of endocrine gland-derived vascular endothelial growth factor and Bombina variegata 8 on steroidogenic adrenocortical cells

Endocrine gland-derived vascular endothelial growth factor (EG-VEGF) and its homolog Bombina variegata (Bv8), also termed prokineticin-1 and -2 (PK1 and PK2) respectively, are newly identified peptides with specific mitogenic activity on endocrine gland-derived endothelial cells. In the present study, we analyzed the sites of expression of EG-VEGF/PK1, Bv8/PK2, and their receptors (PKR1 and PKR2) in the adrenal cortex and checked for new biological functions of these factors on the endocrine cell compartment. RT-PCR and immunostaining analyses revealed that glomerulosa and fasciculata cells express both factors and both receptors. EG-VEGF/PK1 had no effect on the steroidogenic activity of both bovine glomerulosa and fasciculata cells but appeared to be mitogenic for both cell types. Binding of EG-VEGF/PK1 to fasciculata cells stimulated the phosphorylation of ERK1/2. Pretreatment with pertussis toxin suppressed this effect, indicating that it was Gi mediated. EG-VEGF/PK1 also increased the phosphorylation of Akt in endocrine cells of the adrenal cortex. EG-VEGF/PK1 and Bv8/PK2 thus represent new regulatory peptides acting as autocrine mitogens for endocrine cells.

Molecular genetics of the cAMP-dependent protein kinase pathway and of sporadic pituitary tumorigenesis

Pituitary tumors are among the most common human neoplasms. Although these common lesions rarely become clinically manifest and they are almost never malignant, they are the cause of significant morbidity in affected patients. The genetic causes of common pituitary tumors remain for the most part unknown; progress has been limited to the elucidation of the molecular etiology of four genetic syndromes predisposing to pituitary neoplasias: McCune-Albright syndrome, multiple endocrine neoplasia type 1, Carney complex and, most recently, familial acromegaly and prolactinomas and other tumors caused by mutations in the GNAS, menin, PRKAR1A, AIP, and p27 (CDKN1B) genes, respectively. Intense molecular studies of sporadic pituitary tumors from patients with negative family histories and no other neoplasms have yielded interesting findings with abnormalities in growth factor expression and cell cycle control dysregulation. To add to the difficulties in understanding pituitary tumorigenesis in man, good murine models of these neoplasms simply do not exist: pituitary tumors are common in rodents, but their histologic origin (mostly from the intermediate lobe), age of presentation (late in murine life) and clinical course make them hardly models of their human counterparts. The present report reviews the clinical and molecular genetics of the cAMP-dependent protein kinase pathway in human pituitary tumors; it also reviews briefly other pathways that have been involved in sporadic pituitary neoplasms. At the end, we attempt a unifying hypothesis for pituitary tumorigenesis, taking into account data that are also discussed elsewhere in this issue.

Molecular biology of the hst-1 gene

The hst-1 gene (or HSTF1 by human gene nomenclature) was originally identified in our laboratory by an NIH/3T3 focus formation assay using DNA from a human gastric cancer. Sequence analysis predicted the hst-1 product to be a novel growth factor with 30-50% homology with six other heparin-binding growth factors: basic and acidic fibroblast growth factors (FGFs), the int-2 protein, FGF5, the hst-2/FGF6 protein and keratinocyte growth factor (KGF). A recombinant hst-1 protein was synthesized in silkworm cells and found to be a potent heparin-binding mitogen for murine fibroblasts and human vascular endothelial cells. Although hst-1 expression cannot be detected in most cancer cells, including gastric cancers, it is expressed in mouse embryos and in some germ cell tumours. Both hst-1 and int-2 are located on band q13.3 of human chromosome 11 within a distance of 35 kbp; in the mouse genome these two genes are separated by less than 20 kbp. They are differentially transcribed in the F9 mouse teratocarcinoma cell line; hst-1 is expressed in undifferentiated stem cells and int-2 in differentiated endodermal cells. The hst-1 and int-2 genes were coamplified in a variety of cancer cells, most notably in more than 50% of oesophageal cancers.

Molecular signaling in bone regeneration

Regeneration is the ability of cells to restore lost or damaged tissues and organs in adults by pathways that mimic developmental processes. Although many of the molecular mechanisms that control cellular differentiation and growth during embryogenesis recur during fracture healing, these processes take place in a postnatal environment that is unique and distinct from those that exist during embryogenesis. Bone tissue has a remarkable capacity of regeneration without scarring. This article highlights central biological and molecular processes that are crucial in embryonic bone development. Several animal bone regeneration models are described. The patterns of gene expression during the regeneration process in the different models are reviewed. Exploring the similarities and the differences in the molecular processes in different models will contribute to the understanding of their potential in the processes of bone regeneration and tissue engineering.

Neurotrophic and growth factor gene expression profiling of mouse bone marrow stromal cells induced by ischemic brain extracts

Treatment of rodents after stroke with bone marrow stromal cells (BMSCs) improves functional outcome. However, the mechanisms underlying this benefit have not been ascertained. This study focused on the contribution of neurotrophic and growth factors produced by BMSCs to therapeutic benefit. Rats were subjected to middle cerebral artery occlusion and the ischemic brain extract supernatant was collected to prepare the conditioned medium. The counterpart normal brain extract from non-ischemic rats was employed as the experimental control. Using microarray assay, we measured the changes of the neurotrophin associated gene expression profile in BMSCs cultured in different media. Furthermore, real-time RT-PCR and fluorescent immunocytochemistry were utilized to validate the gene changes. The morphology of BMSCs, cultured in the ischemic brain-conditioned medium for 12 h, was dramatically altered from a polygonal and flat appearance to a fibroblast-like long and thin cell appearance, compared to those in the normal brain-conditioned medium and the serum replacement medium. Forty-four neurotrophin-associated genes in BMSCs were identified by microarray assay under all three culture media. Twelve out of the 44 genes (7 neurotrophic and growth factor genes, 5 receptor genes) increased in BMSCs cultured in the ischemic brain-conditioned medium compared to the normal brain-conditioned medium. Real time RT-PCR and immunocytochemistry validated that the ischemic brain-conditioned medium significantly increased 6/7 neurotrophic and growth factor genes, compared with the normal brain-conditioned medium. These six genes consisted of fibroblast growth factor 2, insulin-like growth factor 1, vascular endothelial growth factor A, nerve growth factor beta, brain-derived neurotrophic factor and epidermal growth factor. Our results indicate that transplanted BMSCs may work as 'small molecular factories' by secreting neurotrophins, growth factors and other supportive substances after stroke, which may produce therapeutic benefits in the ischemic brain.

Interferon-beta reduces the mouse liver fibrosis induced by repeated administration of concanavalin A via the direct and indirect effects

Type I interferons (IFNs), IFN-alpha and IFN-beta, are widely used for treating chronic hepatitis C. Although retrospective studies have suggested that type I IFNs have direct antifibrotic effects, little is known about these mechanisms. The present study was designed to clarify the preventive mechanisms of type I IFNs in the progression of fibrosis for the establishment of a more effective therapy. A murine fibrosis model comprising immunological reactions was induced by the administration of concanavalin A (0.3 mg/body) into mice once a week for 4 weeks. Liver injury and the degree of fibrosis were determined by measuring the serum alanine aminotransferase activities and liver hydroxyproline contents with or without IFN-beta pretreatment. IFN-beta suppressed the hepatocellular injury and increased the hydroxyproline content induced by repeated concanavalin A injections, but had no effect on established fibrosis. Furthermore, IFN-beta reduced the expressions of transforming growth factor-beta, basic fibroblast growth factor, collagen type I A2 and tissue inhibitor of metalloproteinase 1 messenger RNAs, which are related to the progression of liver fibrosis. The IFN-beta reduced the liver injury and fibrosis induced by immunological reactions. These data suggest that type I IFNs suppress the progression of cirrhosis through inhibition of repeated hepatocellular injury and/or factors that promote the liver fibrosis induced by hepatitis virus infection.

Oligonucleotide microarray analysis of human lens epithelial cells: TGFbeta regulated gene expression

PURPOSE

Transforming growth factor beta (TGFbeta), a pro-fibrotic cytokine has been proposed a causative factor in the progression of lens pathologies including posterior capsule opacification (PCO), a condition that occurs after cataract surgery. This study employs oligonucleotide microarrays to provide a global profile of gene expression in FHL 124 cells, to identify changes in gene expression following treatment with TGFbeta1 and TGFbeta2, and to enable putative genes relating to TGFbeta regulation and PCO to be identified.

METHODS

Routinely cultured FHL 124 cells maintained in serum free Eagle's Minimum Essential Medium (EMEM) were treated with either TGFbeta1 or TGFbeta2 at 10 ng/ml for 24 h then total RNA extraction was carried out. Total RNA (16 microg) was used to analyze gene expression by spotted oligonucleotide microarray hybridization. The spotted oligonucleotide microarrays employed contained 13,971 oligonucleotide probes, each designed to be specific for an individual gene. Array images were analyzed using GenePix Pro 3.0, followed by raw data import into GeneSpring 7.0 where a cross gene error model (CGEM) filter was applied. Data was subjected to LoWess normalization prior to comparison of the different treatment groups. Quantitative real-time polymerase chain reaction (QRT-PCR) was used to validate the oligonucleotide microarray data, using a select number of genes exhibiting differential expression.

RESULTS

A total of 301 genes were up-regulated by more than 1.5 fold in FHL 124 cells by both TGFbeta1 and TGFbeta2. Many of these up-regulated genes had biological functions relevant to lens epithelial cells including roles in contraction, transdifferentiation and as extracellular matrix (ECM) components. A total of 164 genes were down-regulated by more that 1.5 fold in FHL 124 cells by both TGFbeta1 and TGFbeta2. Many of these down-regulated genes have biological functions including roles in apoptosis, signaling, and as anti-oxidants. Following treatment with TGFbeta1 and TGFbeta2, QRT-PCR successfully validated the differential changes in gene expression detected by oligonucleotide microarrays.

CONCLUSIONS

TGFbeta1 and TGFbeta2 regulate the gene expression of genes that have important roles in human lens epithelial cell biology. Most importantly, TGFbeta induces the gene expression of a number of fibrotic markers which may have a role in promoting the development of PCO such as transdifferentiation markers, contractile factors, and ECM components.

Integration of Steroid and Growth Factor Pathways in Breast Cancer: Focus on Signal Transducers and Activators of Transcription and Their Potential Role in Resistance

The signaling pathways that are critical to the development and growth of breast cancer include those activated downstream of the estrogen receptor (ER) and the human epidermal growth factor receptor family. Many of these pathways, including the signal transducer and activator of transcription pathway, are common to both. The well-described genomic actions of ER involve its role as a transcription factor, either by binding directly to DNA through estrogen response elements, or by tethering to DNA through interaction with other proteins. Nongenomic signaling by the ER involves interaction with membrane-associated signaling proteins such as the c-Src tyrosine kinase and adapter proteins p130Cas and moderator of nongenomic activity of ER. Interactions with the signal transducer and activator of transcription pathway are important in both ER signaling pathways and are critical for estrogen-induced proliferation and tumorigenesis. These mechanisms of signaling cross talk and their role in resistance to antiestrogen therapies are discussed.

Integrin alpha 11 regulates IGF2 expression in fibroblasts to enhance tumorigenicity of human non-small-cell lung cancer cells

Integrin alpha11 (ITGA11/alpha11) is localized to stromal fibroblasts and commonly overexpressed in non-small-cell lung carcinoma (NSCLC). We hypothesized that stromal alpha11 could be important for the tumorigenicity of NSCLC cells. SV40 immortalized mouse embryonic fibroblasts established from wild-type (WT) and Itga11-deficient [knockout (KO)] mice were tested for their tumorigenicity in immune-deficient mice when implanted alone or coimplanted with the A549 human lung adenocarcinoma cells. A549 coimplanted with the fibroblasts showed a markedly enhanced tumor growth rate compared with A549, WT, or KO, which alone formed only small tumors. Importantly, the growth was significantly greater for A549+WT compared with A549+KO tumors. Reexpression of human alpha11 cDNA in KO cells rescued a tumor growth rate to that comparable with the A549+WT tumors. These findings were validated in two other NSCLC cell lines, NCI-H460 and NCI-H520. Gene expression profiling indicated that IGF2 mRNA expression level was >200 times lower in A549+KO compared with A549+WT tumors. Stable short-hairpin RNA (shRNA) down-regulation of IGF2 in WT (WT(shIGF2)) fibroblasts resulted in a decreased growth rate of A549+WT(shIGF2), compared with A549+WT tumors. The results indicate that alpha11 is an important stromal factor in NSCLC and propose a paradigm for carcinoma-stromal interaction indirectly through interaction between the matrix collagen and stromal fibroblasts to stimulate cancer cell growth.

Expression of collagen and related growth factors in rat tendon and skeletal muscle in response to specific contraction types

Acute exercise induces collagen synthesis in both tendon and muscle, indicating an adaptive response in the connective tissue of the muscle-tendon unit. However, the mechanisms of this adaptation, potentially involving collagen-inducing growth factors (such as transforming growth factor-beta-1 (TGF-beta-1)), as well as enzymes related to collagen processing, are not clear. Furthermore, possible differential effects of specific contraction types on collagen regulation have not been investigated. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve. RNA was extracted from medial gastrocnemius and Achilles tendon tissue 24 h after the last training bout, and mRNA levels for collagens I and III, TGF-beta-1, connective tissue growth factor (CTGF), lysyl oxidase (LOX), metalloproteinases (MMP-2 and -9) and their inhibitors (TIMP-1 and 2) were measured by Northern blotting and/or real-time PCR. In tendon, expression of TGF-beta-1 and collagens I and III (but not CTGF) increased in response to all types of training. Similarly, enzymes/factors involved in collagen processing were induced in tendon, especially LOX (up to 37-fold), which could indicate a loading-induced increase in cross-linking of tendon collagen. In skeletal muscle, a similar regulation of gene expression was observed, but in contrast to the tendon response, the effect of eccentric training was significantly greater than the effect of concentric training on the expression of several transcripts. In conclusion, the study supports an involvement of TGF-beta-1 in loading-induced collagen synthesis in the muscle-tendon unit and importantly, it indicates that muscle tissue is more sensitive than tendon to the specific mechanical stimulus.

Interleukin-6 undergoes transition from growth inhibitor associated with neuroendocrine differentiation to stimulator accompanied by androgen receptor activation during LNCaP prostate cancer cell progression

BACKGROUND

Interleukin-6 (IL-6) has been implicated in the modulation of growth and differentiation in many cancers, and is associated with poor prognosis in renal cell carcinoma, ovarian cancer, lymphoma, melanoma, and prostate cancer. The effects of IL-6 on the growth of LNCaP human prostate cancer cells are puzzling with some groups showing growth stimulation, while others showing growth inhibition. In this study, we investigated the discrepancy of the effects of IL-6 on prostate cancer cells.

METHODS

Series of lower and higher passages of LNCaP cell sublines were generated by a long-term exposure of LNCaP cells in IL-6-containing culture media. The characteristics of these cell sublines were analyzed and the potential roles of neuroendocrine (NE) differentiation and androgen receptor (AR) activation were examined.

RESULTS

We demonstrated that while short-term treatment of IL-6 inhibits LNCaP cell growth by a paracrine mechanism associated with NE differentiation, long-term treatment of IL-6 promotes LNCaP cell growth by an autocrine mechanism accompanied by an activation of AR signaling. In the lower passages (less than 28 passages) of LNCaP cells treated with IL-6, the cell growth was severely retarded which is associated with NE-like morphology and increased expression of NE markers such as neuronspecific enolase (NSE) and chromgranin A (ChgA), and loss of AR expression. However, in the higher passages (higher than 42 passages) of LNCaP cells treated with IL-6, cells started to express endogenous IL-6. At the same time, NE characteristics were disappeared, AR signaling was activated and cells growth was accelerated. Knocking down the AR activation of the higher passages of LNCaP cells abolished autocrine IL-6-induced growth stimulation.

CONCLUSIONS

These studies suggest that acquisition of endogenous IL-6 production after prolong exposure of prostate cancer cells to IL-6 may contribute to an autocrine cell growth stimulation. Furthermore, the transition of IL-6 from a paracrine growth inhibitor to an autocrine growth stimulator suggests that IL-6 plays an important role during prostate cancer progression, possibly androgen-independent progression.

Three reactive compartments in venous malformations

Vascular malformations affect 3% of neonates. Venous malformations (VMs) are the largest group representing more than 50% of cases. In hereditary forms of VMs gene mutations have been identified, but for the large group of spontaneous forms the primary cause and downstream dysregulated genes are unknown. We have performed a global comparison of gene expression in slow-flow VMs and normal saphenous veins using human whole genome micro-arrays. Genes of interest were validated with qRT-PCR. Gene expression in the tunica media was studied after laser micro-dissection of small pieces of tissue. Protein expression in endothelial cells (ECs) was studied with antibodies. We detected 511 genes more than four-fold down- and 112 genes more than four-fold up-regulated. Notably, chemokines, growth factors, transcription factors and regulators of extra-cellular matrix (ECM) turnover were regulated. We observed activation and "arterialization" of ECs of the VM proper, whereas ECs of vasa vasorum exhibited up-regulation of inflammation markers. In the tunica media, an altered ECM turnover and composition was found. Our studies demonstrate dysregulated gene expression in tunica interna, media and externa of VMs, and show that each of the three layers represents a reactive compartment. The dysregulated genes may serve as therapeutic targets.

Lack of Spem1 causes aberrant cytoplasm removal, sperm deformation, and male infertility

We identified a previously uncharacterized gene, spermatid maturation 1 (Spem1), encoding a protein exclusively expressed in the cytoplasm of steps 14-16 elongated spermatids in the mouse testis. This protein contains no known functional domains and is highly conserved across mammalian species. Male mice deficient in Spem1 were completely infertile because of deformed sperm characterized by a bent head wrapped around by the neck and the middle piece of the tail. We show that lack of Spem1 causes failure of the cytoplasm to become loose and detach from the head and the neck region of the developing spermatozoa. Retained cytoplasmic components mechanically obstruct the straightening of the sperm head and the stretching of the growing tail, leading to the bending of the head in the neck, followed by the wrapping of the head by the neck or the middle piece of the sperm tail. Our study reveals that proper cytoplasm removal is a genetically regulated process requiring the participation of Spem1 and that lack of Spem1 causes sperm deformation and male infertility.

Fast, hungry and unstable: finding the Achilles' heel of small-cell lung cancer

Over 95% of patients with small-cell lung cancer (SCLC) die within five years of diagnosis. The standard of care and the dismal prognosis for this disease have not changed significantly over the past 25 years. Some of the characteristics of SCLC that have defined it as a particularly virulent form of cancer -- rapid proliferation, excessive metabolic and angiogenic dependence, apoptotic imbalance and genetic instability -- are now being pursued as tumor-specific targets for intervention both in preclinical and early phase clinical studies. Here, we summarize areas of ongoing anti-cancer drug development, including classes of agents that target essential pathways regulating proliferation, angiogenesis, apoptotic resistance, chromosomal and protein stability, and cell-cell and cell-matrix interaction.

Mallory body formation is associated with epigenetic phenotypic change in hepatocytes in vivo

Microarrays were done on the livers of mice fed DDC for 10 weeks, withdrawn 1 month (DDC primed livers) and refed 6 days, and compared with mice fed the control diet. The expression of a large number of genes changed when DDC was fed or refed. A Venn diagram analysis identified 649 genes where gene expression was changed in the same direction. The epigenetic memory of the DDC primed liver involved an increase in the expression of ubiquitin D, alpha fetoprotein, connective tissue growth factor, integrin beta 2, DNA methyl transferase 3a and DNA damage-inducible 45 gamma. DNA methyl transferase 3b was down-regulated as was Cbp/p300. When DDC was refed, DNA methyltransferase and histone deacetylase were up-regulated as shown by microarray analysis. Histone3 lysine9 acetylation was increased by DDC and DDC refeeding and DNA methyltransferases were not changed as shown by Western blot analysis. The data suggest the concept that the epigenetic memory that explains why DDC primed hepatocytes form MBs in 7 days of DDC refeeding is primarily the result of epigenetic modifications of gene expression through changes in histone acetylation and methylation, as well as DNA methylation.

Adipocyte differentiation of human marrow mesenchymal stem cells reduces the supporting capacity for hematopoietic progenitors but not for severe combined immunodeficiency repopulating cells

Bone marrow stromal cells provide a microenvironment for hematopoiesis. Adipocytes are the major stromal cell phenotype in bone marrow, but their function in hematopoiesis is poorly understood. In this study, we compared the hematopoietic-supporting capacity of adipocytes and their progenitor, mesenchymal stem cells (MSCs), by culturing human cord blood (CB) CD34+CD38- hematopoietic progenitor cells (HPCs) on a layer of adipocytes or MSCs. CB CD34+CD38- cells cultured on MSCs generated higher proportions of CD34+CD38- HPCs and colony-forming cells than those cultures on a layer of adipocytes, indicating an inferior hematopoietic support by adipocytes. However, CB CD34+CD38- HPCs cultured on MSCs and adipocytes were equally capable of reconstituting human hematopoiesis in non-obese diabetic/severe combined immunodeficient disease (NOD/SCID) mice. These findings show that differentiation of MSCs into adipocytes is accompanied by the loss of capacity to support mature HPCs, but not transplantable SCID-repopulating cells.

Regenerative inductive therapy based on DDS technology of protein and gene

Recent development of biomedical engineering including biomaterials and drug delivery system (DDS) as well as basic biology and medicine has enabled cells to induce regeneration repairing of defective tissues as well as substitute the biological functions of damaged organs. For successful tissue regeneration, it is undoubtedly indispensable to give cells a local environment which allows cells to efficiently promote their proliferation and differentiation and consequently induce cell-based tissue regeneration. Tissue engineering is one of the biomedical forms to create this regeneration environment of cells. The tissue and organ repairing based on their regeneration induction has been realized by combining cells with the tissue engineering technology or methodology in a surgical or internally medical manner. This paper overviews the present status and future direction of tissue engineering for regenerative inductive therapy, briefly explaining the key technology of tissue engineering, especially DDS of growth factor and gene.

Antimicrobial peptides derived from growth factors

Growth factors, comprising diverse protein and peptide families, are involved in a multitude of developmental processes, including embryogenesis, angiogenesis, and wound healing. Here we show that peptides derived from HB-EGF, amphiregulin, hepatocyte growth factor, PDGF-A and PDGF-B, as well as various FGFs are antimicrobial, demonstrating a previously unknown activity of growth factor-derived peptides. The peptides killed the Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and the Gram-positive Bacillus subtilis, as well as the fungus Candida albicans. Several peptides were also active against the Gram-positive S. aureus. Electron microscopy analysis of peptide-treated bacteria, paired with analysis of peptide effects on liposomes, showed that the peptides exerted membrane-breaking effects similar to those seen after treatment with the "classical" human antimicrobial peptide LL-37. Furthermore, HB-EGF was antibacterial per se, and its epitope GKRKKKGKGLGKKRDPCLRKYK retained its activity in presence of physiological salt and plasma. No discernible hemolysis was noted for the growth factor-derived peptides. Besides providing novel templates for design of peptide-based antimicrobials, our findings demonstrate a previously undisclosed link between the family of growth factors and antimicrobial peptides, both of which are induced during tissue remodelling and repair.

Effects of pleiotrophin, a heparin-binding growth factor, on human primary and immortalized chondrocytes

OBJECTIVE

Pleiotrophin (PTN) is a secreted heparin-binding peptide expressed in mesodermal and neuroectodermal cells during development, but rarely in adult tissues. In fetal and juvenile, but not in mature cartilage, PTN is abundant. Furthermore, PTN is re-expressed in chondrocytes in early stages of osteoarthritis (OA). Since little is known about the functions of PTN in cartilage, we investigated the occurrence of PTN receptors in human articular cartilage in situ and PTN effects on human primary and immortalized chondrocytes in vitro.

METHODS

Receptor expression and regulation was monitored by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. PTN effects and signal transduction were studied by electrophoretic mobility shift, Boyden chamber cell migration and proliferation assays, effects on gene expression by real time RT-PCR and that on nitric oxide (NO) by the Griess reaction.

RESULTS

Of the putative PTN signaling receptors, immortalized and primary chondrocytes (pc) expressed the anaplastic lymphoma kinase (ALK), less the receptor-type protein tyrosine phosphatase zeta/beta (PTPzeta). ALK expression was upregulated upon ligand exposure. PTN stimulation activated the AP-1 (activator protein-1) transcription factor and altered gene expression. Prolonged stimulation induced PTN mRNA expression slightly, reduced vascular endothelial growth factor (VEGF) mRNA as well as NO production. Whereas mRNA expression of matrix metalloproteinases (MMPs) MMP-1 and MMP-13 was reduced, their inhibitors TIMP-1 and TIMP-2 were induced. Furthermore, PTN stimulated chondrocyte migration and proliferation.

CONCLUSIONS

These results show that PTN is an autocrine growth factor in cartilage. We suggest that PTN may be involved in the clustering and proliferation of chondrocytes observed in the early stages of OA.

PACAP induces neurite outgrowth in cultured trigeminal ganglion cells and recovery of corneal sensitivity after flap surgery in rabbits

PURPOSE

To evaluate the ability of pituitary adenylate cyclase-activating polypeptide (PACAP) to induce growth of neuronal processes in cultured trigeminal ganglion cells, and to accelerate neurite outgrowth and recovery of corneal sensitivity after creation of a corneal flap in a rabbit model of laser-assisted in situ keratomileusis (LASIK) surgery.

DESIGN

Animal study.

METHODS

The cDNA of rabbit PACAP was sequenced, and the expression of PACAP receptors in the trigeminal ganglia from rabbits was quantified by quantitative real-time polymerase chain reaction. Trigeminal ganglion cells were isolated from rabbits and cultured for 48 hours with or without PACAP27 (bioactive N-terminal peptide from PACAP). Cells were stained with antibody against neurofilaments, and neurite outgrowth was quantified by cell counting. In the rabbit LASIK model, a corneal flap with a planned thickness of 130 microm and 8.5 mm diameter was created with a microkeratome. The rabbits then received eyedrops containing PACAP27 four times a day for eight weeks, and corneal sensitivity was measured. Neurite outgrowth was assessed by staining histologic sections of the flap area for cholinesterase.

RESULTS

The deduced amino acid sequence of PACAP in rabbit was identical to that of human. PACAP receptor, PAC1, was highly expressed in trigeminal ganglia from newborn and adult rabbits. PACAP27 at 1 microM induced growth of neuronal processes in cultured primary trigeminal ganglion cells. In the LASIK model, extensions of neuronal processes from amputated nerve trunks in cornea were observed after administration of eyedrops containing 1 or 10 microM PACAP27. The 10 microM PACAP27 treatment also greatly accelerated recovery of corneal sensitivity.

CONCLUSIONS

PACAP may be a candidate drug for ameliorating dry eye after LASIK surgery.

A meta-analysis of human embryonic stem cells transcriptome integrated into a web-based expression atlas

Microarray technology provides a unique opportunity to examine gene expression patterns in human embryonic stem cells (hESCs). We performed a meta-analysis of 38 original studies reporting on the transcriptome of hESCs. We determined that 1,076 genes were found to be overexpressed in hESCs by at least three studies when compared to differentiated cell types, thus composing a "consensus hESC gene list." Only one gene was reported by all studies: the homeodomain transcription factor POU5F1/OCT3/4. The list comprised other genes critical for pluripotency such as the transcription factors NANOG and SOX2, and the growth factors TDGF1/CRIPTO and Galanin. We show that CD24 and SEMA6A, two cell surface protein-coding genes from the top of the consensus hESC gene list, display a strong and specific membrane protein expression on hESCs. Moreover, CD24 labeling permits the purification by flow cytometry of hESCs cocultured on human fibroblasts. The consensus hESC gene list also included the FZD7 WNT receptor, the G protein-coupled receptor GPR19, and the HELLS helicase, which could play an important role in hESCs biology. Conversely, we identified 783 genes downregulated in hESCs and reported in at least three studies. This "consensus differentiation gene list" included the IL6ST/GP130 LIF receptor. We created an online hESC expression atlas, http://amazonia.montp.inserm.fr, to provide an easy access to this public transcriptome dataset. Expression histograms comparing hESCs to a broad collection of fetal and adult tissues can be retrieved with this web tool for more than 15,000 genes.

Isolation and Identification of F-Spondin in the Boar Testis and Its Production During Testis Growth

F-spondin/vascular smooth muscle cell growth-promoting factor (VSGP), purified from the follicular fluid of adult bovine ovaries, has been identified as a promoter of neuronal differentiation and vascular smooth muscle growth. The objectives of the present study were (1) to clarify whether F-spondin is also produced in the testis, which is ontogenically equivalent to the ovary, and (2) to examine whether production of this protein changes with testicular growth. To isolate F-spondin from the testis, testicular homogenates obtained from 8-week-old boars were sequentially subjected to heparin-Sepharose chromatography, diethylaminoethyl (DEAE)-Sepharose chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). The isolated protein had a molecular mass of approximately 110 kDa and was cross-reactive with anti-F-spondin antibody by Western blotting. The purified protein was further characterized by amino acid sequence analysis of its internal peptide. The sequence obtained was GEQCNIVPDN VD, and a homology search indicated that the purified protein is a homologue of rat, human, and bovine F-spondin. By fractionation of the same amounts of testis tissue obtained from 1-, 8-, 16-, and 40-week-old boars, we analyzed age-related production of F-spondin in the testis. Western blotting of the fractions obtained from RP-HPLC revealed the presence of a band at approximately 110 kDa, corresponding to F-spondin, in the testes obtained from boars between 1 and 16 weeks old, but this band was not detected at 40 weeks. These results clearly indicate that (1) the porcine testis produces F-spondin and that (2) production of this protein is evident in the immature porcine testis, but not the adult testis.

Ectodomain shedding of the EGF-receptor ligand epigen is mediated by ADAM17

All ligands of the epidermal growth factor receptor (EGFR), which has important roles in development and disease, are made as transmembrane precursors. Proteolytic processing by ADAMs (a disintegrin and metalloprotease) regulates the bioavailability of several EGFR-ligands, yet little is known about the enzyme responsible for processing the recently identified EGFR ligand, epigen. Here we show that ectodomain shedding of epigen requires ADAM17, which can be stimulated by phorbol esters, phosphatase inhibitors and calcium influx. These results suggest that ADAM17 might be a good target to block the release of bioactive epigen, a highly mitogenic ligand of the EGFR which has been implicated in wound healing and cancer.

Effects of oxidized low- and high-density lipoproteins on gene expression of human macrophages

OBJECTIVE

Oxidized low-density lipoprotein (ox-LDL) is a major factor in foam cell formation, whereas the role of oxidized high-density lipoprotein (ox-HDL) in this process is not known. The objective of the present study was to examine the effects of ox-LDL and ox-HDL on the gene expression of cultured human macrophages.

MATERIAL AND METHODS

Gene expression of human macrophages was studied after incubation for 1 day and 3 days with native and oxidized LDL and HDL using cDNA expression array. Expression of granulocyte-macrophage colony-stimulating factor 1, which was constantly up-regulated by ox-LDL and down-regulated by ox-HDL after 1- and 3 days of incubation in cDNA microarray experiments, was verified by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Genes that showed altered expression were divided into six groups; 1) lipid metabolism, 2) inflammation, growth and hemostasis, 3) matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases, 4) enzymes, 5) structural and binding proteins and 6) annexins.

CONCLUSIONS

The microarray method was found to be applicable in analyzing changes in gene expression induced by oxidized lipoproteins in cultured human macrophages. Our results reflect different functional roles of ox-LDL and ox-HDL in foam cell formation.