Biomedical subjects

Katharina Spanel-Borowski

Publications and source records attributed to Katharina Spanel-Borowski.

At least 19 recordsLinked to original sources

PubMed2006

The short prolactin receptor predominates in endothelial cells of micro- and macrovascular origin.

BACKGROUND: Controversial reports on prolactin receptors (PRL-R), the long and short form, on endothelial cells (EC) may be explained by the choice of EC derived from the micro- and macrovascular bed of either endocrine and non-endocrine organs. METHODS: We studied here PRL-R expression in organs [bovine corpus luteum (CL), umbilical vein, aorta] and in organ-derived EC cultures. RESULTS: In the intact CL, both PRL-R forms were present at mRNA and protein level throughout the oestrous cycle stages. The short form prevailed as protein. PRL-R-positive EC were noted by immunofluorescent staining in arterial blood vessels of CL septa, in the umbilical vein and the aorta. In EC cultures of micro- and macrovascular origin, transcripts of both PRL-R forms were shown; again the short-form protein prevailed. Blocking experiments with anti-prolactin (PRL) antibody led to a 60% decrease in cell growth. Treatment with PRL had no effect. CONCLUSION: PRL-R expression in micro- and macrovascular EC is associated with the predominant short form.

Animals↗

PubMed2006

Inverse relationship between nitric oxide synthases and endothelin-1 synthesis in bovine corpus luteum: interactions at the level of luteal endothelial cell.

Endothelin-1 (ET-1) and nitric oxide (NO) play pivotal roles in corpus luteum (CL) function. The present study examined the interplay between NO and ET-1 synthesis in the bovine CL. We found similar inducible and endothelial NO synthase (iNOS and eNOS, respectively) activities in the young CL (d 1-5) expressing the highest levels of both eNOS and iNOS mRNA. These values later declined at mid-cycle (d 8-15) and remained low at later stages (d 16-18). Luteolysis, initiated by prostaglandin F2alpha analog administration, further reduced NOS mRNA and by 24 h, NOS values dropped to approximately 15% of those at mid-cycle. eNOS protein levels followed a similar pattern to its mRNA. Because endothelial cells (ECs) are the main site for ET-1 and NO production in the CL, we examined the direct effects of the NO donor, NONOate on luteal ECs (LECs). Elevated NO levels markedly decreased ET-1 mRNA, and peptide concentrations in cultured and freshly isolated LECs in a dose-dependent manner. In agreement, NOS inhibitor, NG-nitro-l-arginine methyl ester, stimulated ET-1 mRNA expression in these cells. Interestingly, NO also up-regulated prostaglandin F2alpha receptors in LECs. These data show that there is an inverse relationship between NOS and ET-1 throughout the CL life span, and imply that this pattern may be the result of their interaction within the resident LECs. NOS are expressed in a physiologically relevant manner: elevated NO at an early luteal stage is likely to play an important role in angiogenesis, whereas reduced levels of NO during luteal regression may facilitate the sustained up-regulation of ET-1 levels during luteolysis.

Animals↗

PubMed2006

Adipocyte-derived angiopoietin-1 supports neurite outgrowth and synaptogenesis of sensory neurons.

Sensory and sympathetic innervation of the white fat tissue (WAT) contributes to lipolysis. In addition, both fiber types adapt in density to weight gain and loss. Because these findings are indicative for a tight control of nerve fiber plasticity by adipokines, we tested whether adipocytes control neurite growth of sensory neurons through angiopoietin-1 (Ang-1). We further considered initial hints that Ang-1-induced neuritogenesis involves transactivation of the high-affinity nerve growth factor (NGF) receptor trkA. Coculturing dorsal root ganglion (DRG) cells with 3T3-L1 adipocytes supported neurite outgrowth. These neurotrophic effects were associated with the increased expression of Ang-1 (presumably in adipocytes) as well as of trkA. The effects were abolished upon inactivating Ang-1 in culture with selective antibodies. Likewise, neurite outgrowth was impaired in the presence of inactivating NGF antibodies as well as upon inhibition of the NGF high-affinity trkA receptor with the antagonist K252a, indicating a tight cooperation of Ang-1 and NGF in the control of neuritogenesis. DRG-adipipocyte cocultures were further used to establish whether sensory neurons would form synaptic contacts with adipocytes. Electron microscopy demonstrated that cultured sensory neurons develop predominantly neuroneuronal synapses but seem to affect adipocytes by synapses en passant. Comparably to the case for neuritogenesis, expression of the presynaptic protein synaptophysin as well of the postsynaptic protein PSD-95 correlated with Ang-1 levels in culture. It is concluded that adipocyte-secreted Ang-1 supports neurite outgrowth, which is involved in synaptogenesis. The novel function of Ang-1 appears to play a physiological role in WAT plasticity.

3T3-L1 Cells↗

PubMed2006

Lectin-like oxidized low-density lipoprotein receptor-1-mediated autophagy in human granulosa cells as an alternative of programmed cell death.

The LOX-1 receptor, identified on endothelial cells, mediates the uptake of oxidized low-density lipoprotein (oxLDL). The oxLDL-dependent LOX-1 activation causes endothelial cell apoptosis. We here investigated the presence of LOX-1 in granulosa cells from patients under in vitro fertilization therapy. We were interested in the oxLDL-dependent LOX-1 receptor biology, in particular in the induction of apoptosis. In the human ovary, LOX-1 was localized in regressing antral follicles. In granulosa cell cultures, oxLDL-induced mRNA expression of LOX-1 in a time- and dose-dependent manner. The LOX-1 inhibitors (anti-LOX-1 antibody and kappa-carrageenan) abrogated the up-regulation of LOX-1. The oxLDL (100 microg/ml) treatment caused the autophagy form of programmed cell death: 1) reorganization of the actin cytoskeleton at the 6-h time point; 2) uptake of YO-PRO, a marker for the early step of programmed cell death, before propidium iodide staining to signify necrosis; 3) absence of apoptotic bodies and cleaved caspase-3; 4) abundant vacuole formation at the ultrastructural level; and 5) decrease of the autophagosome marker protein MAP LC3-I at the 6-h time point indicative of autophagosome formation. We conclude that follicular atresia is not under the exclusive control of apoptosis. The LOX-1-dependent autophagy represents an alternate form of programmed cell death. Obese women with high blood levels of oxLDL may display an increased rate of autophagic granulosa cell death.

Apoptosis↗

PubMed2006

Coloured plastinates.

To obtain coloured plastinates by colouring anatomical structures in e.g. red, blue and yellow we used different types of chemical reagents. The colours remained stable during dehydration, degreasing and impregnation of specimen with silicone resin. The colours, which penetrated into the specimen, appeared to be included in the plastination process. To prove their stability, the coloured plastinates were exposed to light and heat for more than 5 years. A permanent colouration remained. The coloured plastinates are dry and flexible, odourless and robust. They are instructive and can be used in tutorials, examinations and seminars.

Anatomy↗

PubMed2006

Bridging the gap between anatomy and molecular genetics for an improved understanding of congenital heart disease.

Birth defects are the leading cause of infant mortality and malformations in congenital heart disease (CHD) are among the most prevalent and fatal of all birth defects. Yet the molecular mechanisms leading to CHD are complex and the causes of the cardiac malformations observed in humans are still unclear. In recent years, the pivotal role of certain transcription factors in heart development has been demonstrated, and gene targeting of cardiac-specific transcription factor genes in animal models has provided valuable insights into heart anomalies. Nonetheless results in these models can be species specific, and in humans, germline mutations in transcription factor genes can only account for some cases of CHD. Furthermore, most patients do not have family history of CHD. There is, therefore, a need for a better understanding of the mechanisms in both normal cardiac development and the formation of malformations. The combining of expertise in cardiac anatomy, pathology, and molecular genetics is essential to adequately comprehend developmental abnormalities associated with CHD. To help elucidate genetic alterations in affected tissues of malformed hearts, we carried out genetic analysis of cardiac-specific transcription factor genes from the Leipzig collection of formalin-fixed malformed hearts. Working with this morphologically well-characterized archival material not only provided valuable genetic information associated with disease, but enabled us to put forward a hypothesis of somatic mutations as a novel molecular cause of CHD. Knowledge of cause and disease mechanism may allow for intervention that could modify the degree of cardiac malformations or development of new approaches for prevention of CHD.

Germ-Line Mutation↗

PubMed2006

The dorsal lamina of the rectus sheath: a suitable grafting material for the penile tunica albuginea in Peyronie's disease?

OBJECTIVE: To estimate the morphological suitability of human connective tissue structures from different regions as graft material in Peyronie's disease, and to present preliminary results from 12 patients with grafting of corporal bodies using autologous rectus sheath. PATIENTS AND METHODS: In five male cadavers the penile tunica albuginea was compared with the dorsal lamina of the rectus sheath, the palmar aponeurosis, the iliotibial tract and the Achilles tendon by using histological sections stained with haematoxylin and eosin, Crossmon's trichrome stain and resorcin-fuchsin. Surgical results and complication rates were investigated in 12 patients with Peyronie's disease after grafting the corporal bodies with autologous rectus sheath to correct their penile curvature. RESULTS: On histology, the penile tunica albuginea showed a three-dimensional meshwork of collagenous and elastic fibres. The dorsal lamina of the rectus sheath had a remarkably similar fibre structure. The other tissues had a different histology, with long collagenous fibres in parallel orientation and elastic fibres restricted to the loose connective tissue around blood vessels and nerves. Clinically, the penile deviation was successfully corrected in 10 patients; there were two residual deviations (15 degrees and 35 degrees ). There were minor complications after surgery in six patients, not requiring surgery. CONCLUSIONS: The dorsal lamina of the rectus sheath has similar morphological characteristics to the tunica albuginea, and therefore represents an ideal autologous graft; the first clinical results are promising.

Graft Survival↗

PubMed2005

Prokineticins (endocrine gland-derived vascular endothelial growth factor and BV8) in the bovine ovary: expression and role as mitogens and survival factors for corpus luteum-derived endothelial cells.

A highly vascular endocrine gland, the corpus luteum (CL) is an excellent model for the study of angiogenic factors. Prokineticins (PK-1 and -2), also termed endocrine-gland-derived vascular endothelial growth factor (VEGF) and BV8 are newly identified proteins described as selective angiogenic mitogens. We previously identified PK binding sites, two closely homologous G protein-coupled receptors (PK-R1 and PK-R2) in human and bovine ovarian cells, but their function remained unknown. In this study we examined the presence and effects of PK in CL-derived endothelial and steroidogenic cell types (LEC and LSC, respectively). PK-1 mRNA was identified in CL and follicles by real-time PCR, using primers specific for the bovine PK-1 sequence (retrieved from Bos taurus whole genome shotgun database). PK were potent angiogenic mitogens for LEC; they enhanced cell proliferation, elevated [3H]thymidine incorporation, MAPK activation, and c-jun/fos mRNA expression. The effects of PK proteins on cell survival were examined by nuclear morphology (4',6-diamidino-2-phenylindole dihydrochloride staining), measurement of DNA fragmentation (terminal dUTP nucleotide end labeling assay), and caspase-3 cleavage. Results obtained by these techniques demonstrated that PK protected LEC from serum starvation-induced apoptosis. Stress conditions such as serum withdrawal, TNF-alpha, and hypoxia markedly increased PK-R2 expression, whereas mRNA levels of PK-R1 remained unchanged. These suggest that the antiapoptotic effect of PK-1 on LEC may be mediated via PK-R2. PK-1 increased VEGF mRNA expression by LSC, implying that it could also indirectly, via VEGF, affect luteal angiogenesis. Together, these findings suggest an important role for PK-1 in luteal function by acting as a mitogen and survival factor in LEC.

Amino Acid Sequence↗

PubMed2005

Epidermal growth factor-induced hepatocellular carcinoma: gene expression profiles in precursor lesions, early stage and solitary tumours.

Epidermal growth factor is an important mitogen for hepatocytes. Its overexpression promotes hepatocellular carcinogenesis. To identify the network of genes regulated through EGF, we investigated the liver transcriptome during various stages of hepatocarcinogenesis in EGF2B transgenic mice. Targeted overexpression of IgEGF induced distinct hepatocellular lesions and eventually solid tumours at the age of 6-8 months, as evidenced by histopathology. We used the murine MG U74Av2 oligonucleotide microarrays to identify transcript signatures in 12 tumours of small (n=5, pooled), medium (n=4) and large sizes (n=3), and compared the findings with three nontumorous transgenic livers and four control livers. Global gene expression analysis at successive stages of carcinogenesis revealed hallmarks linked to tumour size. A comparison of gene expression profiles of nontumorous transgenic liver versus control liver provided insight into the initial events predisposing liver cells to malignant transformation, and we found overexpression of c-fos, eps-15, TGIF, IGFBP1, Alcam, ets-2 and repression of Gas-1 as distinct events. Further, when gene expression profiles of small manifested tumours were compared with nontumorous transgenic liver, additional changes were obvious and included overexpression of junB, Id-1, minopontin, villin, claudin-7, RR M2, p34cdc2, cyclinD1 and cyclinB1 among others. These genes are therefore strongly associated with tumour formation. Our study provided new information on the tumour stage-dependent network of EGF-regulated genes, and we identified candidate genes linked to tumorigenes and progression of disease.

Animals↗

PubMed2005

Angiopoietin-1 promotes neurite outgrowth from dorsal root ganglion cells positive for Tie-2 receptor.

The effects of vascular factors on the nervous system are still poorly investigated. Angiopoietin-1 (Ang-1), an endothelial cell growth factor with influences on blood vessel stabilization, has been recently reported to prevent apoptosis in a neuroblastoma cell line via a pathway dependent on Tie-2 receptor. The present study focuses on the effect of Ang-1 on cultured dorsal root ganglion (DRG) cells isolated from 1-day-old rats. Three-day-old DRG cultures were exposed to Ang-1 treatment under serum-free condition for another 5 days and stained with antibodies against neurofilament (NF) 200 protein. Neurite length and density increased compared with those of controls. Double-immunofluorescence staining demonstrated the co-localization of the Tie-2 receptor in some NF-200-positive perikarya. The reverse transcription/polymerase chain reaction technique identified Tie-2 receptor mRNA in intact DRG and in Ang-1-stimulated DRG cell cultures, but not in a Schwann cell line or in primary astrocyte cultures. Western blotting confirmed that the expression of NF 68 protein in cultures treated with Ang-1 or nerve growth factor was higher than that in cultures treated with medium alone. When the Tie-2 receptor was blocked with anti-Tie-2 receptor antibody, neurite outgrowth was severely impeded. Induction of trkA-receptor protein expression was observed to be dependent on the presence of Tie-2 receptors. We conclude that Ang-1 promotes neurite outgrowth from DRG cells positive for Tie-2 receptor. The signalling pathway appears to involve transactivation of the trkA receptor.

Angiopoietin-1↗

PubMed2005

Coexpression of preprotachykinin A and B transcripts in the bovine corpus luteum and evidence for functional neurokinin receptor activity in luteal endothelial cells and ovarian macrophages.

Nonneuronal cell sources of tachykinins, such as substance P (SP) and neurokinin B (NKB), have been demonstrated in leukocytes, endothelial cells and endocrine cells, and may play a role in corpus luteum (CL) development. For this reason, we analyzed mRNA presence for the two tachykinin precursors together with the neurokinin-1 receptor and the neurokinin-3 receptor (NK-1R and NK-3R, preferred by SP and NKB, respectively) in bovine CL at various stages in the luteal phase. Using the RT-PCR technique, we detected coexpression for the preprotachykinin A gene (PPT-A), which encodes SP and neurokinin A (NKA), and the preprotachykinin B gene (PPT-B) for NKB in the CL at the development, secretion and regression stages. Coexpression was also noted for NK-1R and NK-3R gene transcripts. Cultures of endothelial cells (ECs) derived from bovine CL expressed NK-1R and NK-3R mRNA, as did ovarian macrophages. Agonist treatment induced a stronger intracellular calcium ([Ca2+]i) increase after activation of NK-1R compared to NK-3R, a result that we verified by calcium imaging. This is the first evidence for functional tachykinin receptor activity in luteal ECs and ovarian macrophages from bovine CL.

Animals↗

PubMed2005

Expression of nerve growth factor (NGF) isoforms in the rat uterus during pregnancy: accumulation of precursor proNGF.

The mechanisms that promote the transient degenerative changes in the uterus innervation during pregnancy remain incompletely understood. Signaling by the nerve growth factor (NGF)-beta is important for maintaining the density of peripheral sympathetic innervation. Here, we analyzed the spatial and temporal expression of NGF isoforms in the rat uterus using RT-PCR, immunoblot analysis, and immunohistochemistry during pregnancy (d 7, 14, and 21), and postpartum (d 1, 8, and 22). Western blot analysis using antibodies to mature NGF-beta and to proNGF domain demonstrated a significant decrease in mature NGF-beta at gestational d 14 and 21 (term pregnancy) and 1 d postpartum, which paralleled a remarkable accumulation of the 26-28-, 32-, and 60-kDa proNGF forms. There were diminished ratios of mature NGF-beta to proNGF independent of uterus growth on the same gestational days. Immunohistochemistry revealed a progressive NGF-beta decline throughout pregnancy in the myometrium and a near absence at term pregnancy, which contrasted with increased NGF immunostaining in the intermyometrial connective tissue layers. More importantly, proNGF-specific antibodies identified the increased NGF immunoreactivity in the intermyometrial layers at term pregnancy as proNGF and not mature NGF-beta. Alterations in the processing of NGF and accumulation of proNGF in the intermyometrial layers, where axonal degeneration occurs, may contribute significantly to the pregnancy-related uterine denervation and to the control of myometrial activity.

Animals↗

PubMed2004

Transcripts of neurokinin B and neurokinin 3 receptor in superovulated rat ovaries and increased number of corpora lutea as a non-specific effect of intraperitoneal agonist application.

Neurokinin B (NKB), a member of the tachykinin family, and its neurokinin 3 receptor (NK3-R) are preferentially found in the central nervous system. Others have recently reported on mRNA from this ligand-receptor system in the uterus and on NK3-R expression increasing with age. NKB and NK3-R mRNAs have also been noted in cumulus cells and oocytes from superovulated rats. Intact ovaries before and after puberty have not been studied. In this study, we stimulated 29-day-old rats by s.c. injections with gonadotropins for estrous cycle synchronization in order to elucidate the NKB-NK3-R system's expression and function in the ovary. Simultaneously, NaCl, the NK3-R agonist (Pro(7))-NKB, the antagonist SB 218795, or thiorphan, a neutral endopeptidase inhibitor of tachykinin degradation, were injected intraperitoneally (i.p.) for 3 1/2 consecutive days. First, we demonstrated NKB and NK3-R transcripts in one rat ovary by RT-PCR. No significant mRNA differences were noted between immature ovaries and superovulated ovaries in any of the i.p. applications. Second, the possible role of NK3-R on the ovulatory process was verified by counting corpora lutea (CL) and CL cysts in serial sections of the other ovary derived from the four different groups and embedded in paraffin wax. CL and CL cysts were noted in greater numbers in the pharmacologically treated groups than in the saline-treated group. To validate possible drug effects on the peritoneum, we additionally studied pieces of the omentum majus and retroperitoneal fat tissue. Both tissues were heavily infiltrated by granulocytes similar to a non-specific inflammatory response. The saline-treated group as well as the pharmacologically treated groups appeared to develop this unexpected side effect to a similar degree. We conclude that transcripts of NKB and NK3-R are present before and after puberty in the rat ovary and appear to be expressed at similar levels which may indicate a role for the NKB-NK3-R system in follicle growth. The effect of increased CL formation after application of the NK3-R agonist i.p. is related to a non-specific response.

Animals↗

PubMed2004

Increased formation of corpora lutea in neurokinin 1-receptor deficient mice.

There is evidence to suggest that the tachykinin-receptor system may be involved in female reproduction. Recently, we have shown that the mRNA transcripts of the preprotachykinin-A which encodes substance P (SP), a member of the tachykinin family, and of NK1-R (preferred receptor of SP) are expressed in the bovine corpus luteum (CL) of early developmental stage. The question arises whether the system is expressed at the protein level and influences the ovulatory process and CL formation. For this reason, ovaries from a mouse mutant in which the NK1-R gene had been disrupted were studied. By using RT-PCR, mRNA expression of NK1-R was confirmed in both the ovary and the uterus of wild-type mice. Weaning frequency and litter size, as recorded over 6 months, were similar in both groups. However, counting of CL in serial paraffin sections revealed a significant higher number of CL in the NK1-R deficient mice in comparison to the wild-type group (P < 0.01). The increased formation of CL in NK1-R deficient mice corresponded to a considerable number of CL with retained oocyte not found in ovaries of the wild-type group. We conclude: The CL with a retained oocyte may indicate that the muscular apparatus of the preovulatory follicle plays a role in oocyte expulsion and that contractility of the follicle wall is deficient in the mutant group. Our observation may have implications for the luteinized unruptured follicle syndrome in humans.

Animals↗

PubMed2004

Novel NKX2-5 mutations in diseased heart tissues of patients with cardiac malformations.

NKX2-5 is a homeodomain-containing transcription factor important in cardiac development. Familial mutations in the NKX2-5 gene are associated with cardiac abnormalities, but mutations are rare in sporadic cases. We studied the pathology and molecular genetics of NKX2-5 in diseased heart tissues of 68 patients with complex congenital heart disease (CHD), particularly atrial (ASD), ventricular (VSD), and atrioventricular septal defects (AVSD). We also studied DNA extracted from 16 normal hearts, as well as lymphocytic DNA from 50 healthy volunteers, 7 families, and 4 unrelated individuals with CHD. Direct sequencing revealed 53 NKX2-5 mutations in the diseased heart tissues, including nonsynonymous substitutions in the homeodomain of NKX2-5. We found common mutations among unrelated patients, but certain mutations were specific to VSDs and AVSDs. Many patients had multiple NKX2-5 mutations, up to 14 nonsynonymous mutations per patient in VSDs. Importantly, these nonsynonymous mutations were mainly absent in normal heart tissues of the same CHD patients, thus indicating somatic origin and mosaicism of mutations. Further, observed mutations were completely absent in normal hearts and lymphocytic DNA of healthy individuals. Our findings provide new insights for somatic NKX2-5 mutations to be of importance in congenital heart disease.

Base Sequence↗

PubMed2004

Characterization of endothelin-1 and nitric oxide generating systems in corpus luteum-derived endothelial cells.

Endothelium-derived endothelin-1 (ET-1) and nitric oxide (NO) are pivotal regulators of corpus luteum (CL) function. To have a better insight into their synthesis and action, members of the ET system (ET-1, ET converting enzyme (ECE-1) isoforms a-d, ETA and ETB receptors) along with NO synthase (NOS) isoforms--endothelial (e)NOS and inducible (i)NOS--were quantified in CL-derived endothelial cells (CLEC). The expression of these genes in microvascular CLEC, obtained by lectin-coated magnetic beads, was compared with cells removed from the luteal microenvironment and maintained in culture for different durations, and with endothelial cells (EC) derived from a large blood vessel (i.e. bovine aortic endothelial cells, BAEC). The profile of gene expression in the different EC types was determined by quantitative real-time PCR. Freshly isolated EC from mid-cycle CL exhibited high ET-1 receptor expression (both ETA and ETB), low ET-1 synthesizing ability (both prepro (pp) ET-1 and ECE-1), but elevated iNOS - the high throughput NOS isoform. The distinct phenotype of CLEC was lost soon after an overnight culture. ETA and ETB receptor levels declined, ppET-1 levels increased while iNOS was reduced. These changes were extenuated during long-term culture of CLEC. The general pattern of gene expression in BAEC and long-term cultured CLEC was similar yet some differences, reminiscent of freshly isolated CLEC, remained: ECE-1c, ETB receptor and NOS isoforms were expressed differently in BAEC as compared with lines of CLEC. This study suggests that the luteal microenvironment is necessary to sustain the selective phenotype of its resident endothelial cells. The inverse relationship between ppET-1 and iNOS observed in freshly isolated CLEC and in cultured cells is physiologically significant and suggests that ET-1 and NO may modulate the production of each other.

Animals↗

PubMed2003

Differences between retinal and choroidal microvascular endothelial cells (MVECs) under normal and hypoxic conditions.

The morphological and functional differences between the retinal and choroidal vascular bed raise the question of whether the smallest functional unit, the microvascular endothelial cell (MVEC), also differs in its basal characteristics. Here, we examined bovine retinal and choroidal MVECs (rMVECs, cMVECs) for the presence and regulation of angiogenic mediators and their receptors, and cytokines at the mRNA level using quantitative RT-PCR and differential display. Vascular endothelial growth factor (VEGF) mRNA was expressed in both rMVECs and cMVECs. The basal and hypoxia-increased VEGF mRNA levels were significantly higher in cMVECs, which may indicate a higher capacity for autocrine stimulation in these cells. The mRNA for two VEGF receptors, Flt-1 and Flk-1, was present in rMVECs and cMVECs. Interestingly, rMVECs expressed higher Flt-1 but lower Flk-1 mRNA levels compared to cMVECs. Examining the angiopoietin (Ang)/Tie-2 system, we only detected Ang-1 mRNA at very low levels. While Ang-2 mRNA levels were high in both rMVECs and cMVECs, rMVECs expressed 2-3 times the basal and hypoxia-upregulated Ang-2 mRNA levels than did cMVECs. No difference was found in basal Tie-2 mRNA levels. rMVECs are the more potent producers of macrophage colony-stimulating factor (M-CSF) and granulocyte-macrophage CSF (GM-CSF), whereas cMVECs expressed higher RANTES mRNA levels. In our second approach - screening rMVECs and cMVECs for differentially expressed genes - we found liprin-beta1, calnexin, and sushi-repeat-containing protein, x chromosome (SRPX) mRNA in both MVEC types at varying levels. In summary, MVECs from the retinal and choroidal vascular beds showed quantitative differences in angiogenic regulator expression and in their capability to produce cytokines.

Animals↗

PubMed2003

Estrogen receptor expression and synthesis in the human internal thoracic artery.

The inhibition of vascular smooth muscle cell proliferation is mediated through two intracellular estrogen receptors (ERs), ER-alpha and ER-beta. Deletion variants of ER-alpha have been decribed for cultures of smooth muscle cells. The internal thoracic artery is frequently used as coronary artery bypass graft, yet neither has it been studied for the expression of ER subtypes nor for the synthesis of the ERs in morphologically hetergeneous smooth muscle cells. Using nested RT-PCR, we have demonstrated the mRNA for ER-alpha splicing variants in intact human internal thoracic arteries. The 7A deletion variant occurred in 8 out of 12 cases, the full-length transcript in three cases. The full-length transcript was always found for the ER-beta. Immunolocalization revealed ER-positive nuclei in the desmin-positive subset of smooth muscle cells, but not in cytokeratin (CK)-positive cells of the thickened intima. Morphological evidence is presented suggesting that ER synthesis is high in the tunica media when cell proliferation of smooth muscle cells is increased. We conclude that, in internal thoracic arteries, the 7A deletion variant of ER-a occurs in 75%, whereas the full-length transcript is found in all cases. The significance remains unclear.

Alternative Splicing↗