Human Preosteoblastic Cell Culture from a Patient with Severe Tumoral Calcinosis-Hyperphosphatemia Due to a New GALNT3 Gene Mutation: Study of In Vitro Mineralization.

Human disorders of phosphate (Pi) handling and skeletal mineralization represent a group of rare bone diseases. One of these disease is tumoral calcinosis (TC). In this study, we present the case of a patient with TC with a new GALNT3 gene mutation. We also performed functional studies using an in vitro cellular model. Genomic DNA was extracted from peripheral blood collected from a teenage Caucasian girl affected by TC, and from her parents. A higher capability to form mineralization nodules in vitro was found in human preosteoblastic cells of mutant when compared to wild-type controls. We found a novel homozygous inactivating splice site mutation in intron I (c.516-2a>g). A higher capability to form mineralization nodules in vitro was found in the mutant cells in human preosteoblastic cells when compared to wild-type controls. Understanding the functional significance and molecular physiology of this novel mutation will help to define the role of FGF23 in the control of Pi homeostasis in normal and in pathological conditions.

Characterization of the functional and growth properties of long-term cell cultures established from a human somatostatinoma.

In somatostatinoma, a rare malignant somatostatin (SST)-secreting neoplasia, tumour regression is rarely observed, implying the need for novel antiproliferative strategies. Here, we characterized a long-term culture (SST-secreting cancer (SS-C cells)) established from a human somatostatinoma. High concentrations of SST and chromogranin A were released by SS-C cells and SST release was stimulated by depolarizing stimuli and inhibited by the SST analogue, octreotide. SS-C cells expressed mRNA for SST receptor (SSTR) subtypes 1, 2 and 4, being also able to bind native SST. Moreover, SS-C cells were positively stained with an antibody to SSTR2. SS-C cells also expressed interferon-gamma (IFN-gamma) receptor mRNA and measurable telomerase activity. Our findings indicate that in vitro exposure of SS-C cells to native SST-28, to octreotide, to IFN-gamma, or to 3'-azido-3'deoxythymidine (AZT), a telomerase inhibitor, results in inhibition of SS-C cell proliferation. Concomitant with growth inhibition, apoptosis was detected in SST-, octreotide-, IFN-gamma- or AZT-treated SS-C cell cultures. Taken together our results characterized native SST, SST analogues, IFN-gamma and a telomerase inhibitor as growth-inhibiting and proapoptotic stimuli in cultured human somatostatinoma cells. Based on these findings, the potential of SST analogues, IFN-gamma and AZT, alone or in combination, should be further explored in the medical treatment of somatostatinoma.

In Vitro Effects of Strontium on Proliferation and Osteoinduction of Human Preadipocytes.

Development of tools to be used for in vivo bone tissue regeneration focuses on cellular models and differentiation processes. In searching for all the optimal sources, adipose tissue-derived mesenchymal stem cells (hADSCs or preadipocytes) are able to differentiate into osteoblasts with analogous characteristics to bone marrow mesenchymal stem cells, producing alkaline phosphatase (ALP), collagen, osteocalcin, and calcified nodules, mainly composed of hydroxyapatite (HA). The possibility to influence bone differentiation of stem cells encompasses local and systemic methods, including the use of drugs administered systemically. Among the latter, strontium ranelate (SR) represents an interesting compound, acting as an uncoupling factor that stimulates bone formation and inhibits bone resorption. The aim of our study was to evaluate the in vitro effects of a wide range of strontium (Sr(2+)) concentrations on proliferation, ALP activity, and mineralization of a novel finite clonal hADSCs cell line, named PA20-h5. Sr(2+) promoted PA20-h5 cell proliferation while inducing the increase of ALP activity and gene expression as well as HA production during in vitro osteoinduction. These findings indicate a role for Sr(2+) in supporting bone regeneration during the process of skeletal repair in general, and, more specifically, when cell therapies are applied.

Ability of monoclonal antibodies to the thyrotropin receptor to increase collagen synthesis in human fibroblasts: an assay which appears to measure exophthalmogenic immunoglobulins in Graves' sera.

Immunoglobulin G (IgG) preparations from 17 of 20 hyperthyroid patients with Graves' ophthalmopathy stimulated collagen biosynthesis in human fibroblasts, as measured by [3H]proline incorporation. This activity was not associated with thyroid-stimulating antibody (TSAb) activity in a thyroid cell cAMP assay in 50% of the IgG preparations, and it was not found in IgGs from 12 normal subjects, 7 of 8 patients with Graves' hyperthyroidism but no ophthalmopathy, 4 patients with Hashimoto's disease, 7 patients with nontoxic goiter, or 4 hypothyroid patients. In the same assay, 11E8, 22A6, and 13D11, 3 mouse monoclonal antibodies to the bovine TSH receptor, and 307H6, a human monoclonal antibody to the TSH receptor of the thyroid from a Graves' patient with ophthalmopathy, also stimulated [3H]proline incorporation into collagen and were active at more than 1,000- to 10,000-fold lower IgG concentrations (0.1-0.5 microgram/ml as opposed to greater than 1 mg/ml). 11E8 and 13D11 are TSH binding inhibitory antibodies (TBIAbs); 22A6 and 307H6 are TSAbs in cAMP assays. Two other mouse anti-TSH receptor monoclonal antibodies, both TBIAbs, as well as 8 human monoclonal antibodies to the TSH receptor from Graves' patients with or without ophthalmopathy (2 TBIAbs and 6 TSAbs) were negative or significantly less potent (greater than 50 fold) in the assay. The fibroblast activity of the monoclonal antibodies was lost if the antibodies were preincubated with thyroid membranes, was significantly decreased when fibroblasts were exposed to mild trypsin treatment before the assay, was not inhibited by human asialoagalacto-thyroglobulin, and required more than a TSH receptor determinant, since TSH alone neither duplicated nor inhibited the antibody activity. In summary, an assay for measuring the activity of autoantibodies active in causing ophthalmopathy is described, and some but not all TSH receptor monoclonal antibodies have been found to duplicate the action of the autoimmune IgGs from the ophthalmopathy patients.

IGFBPs modulate IGF-I- and high glucose-controlled growth of human retinal endothelial cells.

Insulin-like growth factor binding proteins (IGFBPs) are important local factors in the development of proliferative diabetic retinopathy. We investigated the effects of IGF-I and increased glucose concentrations on the release of IGFBPs and the growth of human retinal endothelial cells (HRECs). HRECs secrete IGFBPs-2 to -5. IGF-I stimulated thymidine incorporation and modified the pattern of IGFBPs, decreasing the inhibitory IGFBP-4 through down-regulation of its mRNA, and increasing IGFBP-5 which, per se, was able to modulate HREC growth, exerting post-transcriptional control. Studies using an antibody (alpha IR3) against the IGF-I receptor, and compounds with low affinity for IGFBPs, such as insulin and des(1-3)IGF-I, showed that an interaction between IGF-I and IGFBP-5 was necessary to detach this IGFBP from its binding sites. The dose of IGF-I that significantly decreased the IGFBP-4/IGFBP-5 ratio was the same that stimulated HREC growth. Chronic exposure to high concentrations of glucose was able to reduce HREC mitogenesis, interacting with the IGF system through a decrease in the stimulatory IGFBPs-2, -3 and -5, leaving the concentration of the inhibitory IGFBP-4 constant. These results extend our previous observations in endothelial cells and suggest that the IGFBP-4/IGFBP-5 ratio regulates IGF-I-induced growth of HRECs, whereas a general decrease in IGFBPs (except for IGFBP-4) was the anti-proliferative effect of chronic exposure to high glucose concentrations.

Human GnRH-secreting cultured neurons express activin betaA subunit mRNA and secrete dimeric activin A.

OBJECTIVE: To evaluate the expression of activin betaA-subunit mRNA and the secretion of activin A in/from cultured GnRH-secreting neuronal cells cloned from human olfactory epithelium (FNC-B4), which showed biochemical and antigenic properties of GnRH-secreting neurons. DESIGN: FNC-B4 cells were cultured in basal and conditioned media. METHODS: Reverse transcription-polymerase chain reaction (RTR-PCR) evaluated the expression of activin betaA-subunit mRNA. By using a specific ELISA, dimeric activin A concentrations were measured in culture media, in the absence or presence of carvone or forskolin and with different doses of progesterone, GnRH, and estradiol. RESULTS: RT-PCR experiments performed on total RNA isolated from FNC-B4 cells, using specific primers for the activin betaA gene, showed a 787bp DNA band corresponding to the betaA gene. FNC-B4 cells secreted activin A, and the highest accumulation in conditioned medium was achieved after 3h culture: the addition of forskolin, but not of carvone, was able to stimulate the release of activin A from cultured neuronal cells (P<0.01). When progesterone or GnRH was added, a significant accumulation of activin A was observed (P<0.01), while estradiol administration did not significantly affect activin A secretion. CONCLUSION: To date, this is the only study, in an in vitro human model reporting, that GnRH-secreting neuronal cells expressed activin betaA-subunit mRNA, and released dimeric activin A in culture medium. The expression and secretion of activin suggests that in these cells activin A might exert its action by autocrine/paracrine mechanisms.

Dyspnea, respiratory function and sputum profile in asthmatic patients during exacerbations.

Dyspnea is often used as a marker of asthma severity although a wide variation in dyspnea perception associated with bronchoconstriction (PB) has been described in asthmatic patients. Our hypothesis is that changes of airway inflammation, airway narrowing and hyperinflation may account for a part of the variability of breathlessness in spontaneous asthma attack. In asthmatic patients with exacerbation of the disease, we evaluated respiratory function, dyspnea (using visual Analogue Scale--VAS) and peak expiratory flow (PEF) values and variability (amplitude % mean), and sputum cellular and biochemical profile before (day I) and after (day II) therapy with i.v. corticosteroids and inhaled beta2-agonists, as appropriate. By day II, forced expiratory volume in 1 s (FEV1), inspiratory capacity (IC), PEF or VAS values and variability, sputum eosinophils and eosinophilic cationic protein (ECP) had improved. Improvement of dyspnea expressed as a decrease in VAS and reduction in variability of dyspnea sensation significantly correlated with increase in FEV1 %predicted value (%pv) (P=0.03; p=0.72 and P=0.02; p=0.74, respectively). No significant correlation was found between IC and VAS either in absolute values or as changes from days I and II, nor between sputum outcomes and PEF or VAS, regardless of how they were measured. We conclude that in acute asthmatic patients, dyspnea measurement, functional measurements and sputum analysis may be useful in monitoring disease activity, response to therapy and can provide different information on the state of the disease.

Interaction between iodothyronines and thyrotropin receptor in human cultured thyroid cells.

In order to verify the existence of a "short-loop" negative feedback between iodothyronines and adenylate cyclase system of human thyroid, we have studied the effect of preincubation with iodothyronines, iodotyrosines, iodothyronine analogues and iodide on TSH-induced cAMP cellular accumulation in normal human thyroid cells in primary culture. Iodide did not produce an inhibitory effect on TSH-dependent adenylate cyclase system both in normal human thyroid plasma membranes and cultured cells. Iodothyronines at a 30-40 microM concentration did not inhibit the TSH-dependent adenylate cyclase activity of human thyroid plasma membranes; however at a 1 microM concentration they were able to inhibit the TSH-dependent cAMP accumulation by cultured cells. Preincubation with iodotyrosines and iodothyronine analogues failed to inhibit the TSH-responsive cAMP accumulation in human thyroid cultured cells.

Sputum processing: a new method to improve cytospin quality.

BACKGROUND: Sputum examination is being increasingly used as a non-invasive method for studying airway inflammation. However, the application of sputum still presents some methodological problems and the results of sputum analysis may be substantially flawed by salivary contamination, cell and mucus debris. In addition, much work is needed to deepen the possibility of extensive application of cell and molecular biology techniques to sputum analysis. OBJECTIVE: In an attempt to improve the technique of sputum processing, we investigated the effect of: (i) 20 and 11 microm filtration in addition to 40 microm on salivary contamination; (ii) Percoll density gradient centrifugation on sputum slides quality; (iii) a culture medium (Minimum Essential Medium containing HEPES 22 mm, pH 7.4: MEM) as washing and suspension solution compared to PBS on cell viability. METHODS: Induced sputum samples were obtained in 37 asthmatics. 21 samples were processed as selected sputum and 16 samples as entire expectorates. After dithiotreitol (DTT) homogenization, each specimen was aliquoted in two parts of equal volume. One portion was processed with the usual method, the other using a modified method: cell pellet was suspended in sterile MEM, filtered through 40, 20 and 11 microm net filters and separated from the residual debris by Percoll gradient centrifugation. RESULTS: As compared to the current sputum processing this method resulted in: (i) no selective bronchial cellular loss; (ii) a significant decrease of salivary contamination, particularly in entire expectorates in which squamous cells were reduced from 47 (36) to 15.5% (20) as median values and interquartile range; (iii) a higher proportion of good quality cytospins; (iv) maintenance of cell viability over the time (88% vs. 81% in MEM and PBS, respectively) 1 h after sample collection. CONCLUSION: In the present study we demonstrated that the proposed method is feasible and makes it possible to overcome most of the technical limits met with the commonly used method, pointing to a potential extension of induced sputum application for more sophisticated techniques.

Loss of adrenergic regulation of cAMP production in the FRTL-5 cell line.

Rat thyroid cells in primary culture augment cAMP production when challenged with beta-adrenergic agonists; at 10(-5) M the potency is isoproterenol greater than norepinephrine greater than epinephrine. In analogy with human thyroid cells, rat thyroid primary cultures display alpha-adrenergic-stimulated cGMP production which inhibits TSH and norepinephrine stimulation of cAMP. Adrenergic regulation of cyclic nucelotide production is lost in the cloned thyroid cell line of rat origin known as FRTL-5. Also the potentiating effect of phentolamine on TSH stimulation of cAMP production in thyroid primary culture becomes an inhibitory one in the FRTL-5 cells. Neither 'soluble factors' nor contamination of other cell populations could account for the different behaviour of the primary culture and the cell line toward adrenergic regulation. The reported activation by norepinephrine of iodide efflux in FRTL-5 cells rules out the loss of specific adrenergic receptors in the FRTL-5 cells. It is proposed that the cloning of FRTL-5 cells from primary cultures causes an 'alteration' in the coupling of adrenergic receptors to the adenylate cyclase system. This alteration does no affect those mechanism of message transduction that do not involve cAMP as the signal.

Parathyroid hormone bioassay using human kidney cortical cells in primary culture.

The biological activity of parathyroid hormone (PTH) has been investigated by measuring intracellular accumulation of cyclic AMP (cAMP) in human kidney cortical cultures. Enzyme dispersed cortical cells from non-invaded kidney poles of patients undergoing nephrectomy for cancer were used after 5 days of primary culture. Bovine PTH (1-84) produced a significant increase of cAMP accumulation in cultured cells at a dose (53.7 ng/ml) 10-fold lower than that found for the minimal stimulatory effect when using preparations of human purified plasma membranes. The action of bovine PTH (1-84) was very rapid, a response was detected after 5 min and a ceiling effect after 30 min. Cortical cells showed a slightly lower sensitivity to synthetic bovine PTH (1-34) (half maximal increase dose: 0.66 microgram/ml), compared to bovine PTH (1-84) (half maximal increase dose: 0.32 microgram/ml), but revealed a higher sensitivity to human PTH purified from the medium of parathyroid cell cultures (half maximal increase dose: 11.2 ng/ml). Arginine-vasopressin (AVP) also increased the cAMP accumulation of kidney cortical cultured cells, with a potency and efficacy lower than that of human 'culture' PTH, while in kidney medullary cells in primary culture AVP exerted a strong response and the effect of PTH was poor or absent. Calcitonin and glucagon were weak stimulators of kidney cortical cell cAMP accumulation.

Studies of catecholamine effect on cyclic AMP in human cultured thyroid cells: their interaction with thyrotrophin receptor.

Even though adrenergic nerve terminals between and around thyroid follicles and catecholamine stimulation of thyroid adenylate cyclase have been reported, there is no uniform concept on catecholamine interaction with thyrotrophin (TSH) receptors. Therefore, the effect of catecholamines on TSH-stimulated cyclic AMP (cAMP) accumulation in human follicular thyroid cells has been investigated, to thus eliminating the extrathyroidal actions of catecholamines. Epinephrine, norepinephrine and isoproterenol appeared to be rapid and potent stimulators of intracellular cAMP accumulation, the half maximum increase doses being 4 X 10(-7)M, 1 X 10(-5)M and 5 X 10(-7)M, respectively. While propranolol (1 X 10(-5)M) prevented the stimulatory effect of catecholamines and failed to inhibit the effect of bovine TSH, phentolamine (1 X 10(-5)M) enhanced the potency of norepinephrine and bovine TSH, leaving that of epinephrine unchanged. The effects of epinephrine (2 X 10(-8)M) and isoproterenol (2 X 10(-8)M) were additive to that of bovine TSH (0.5 mU/ml), but the effect of simultaneous stimulation with norepinephrine (5 X 10(-7)M) and bovine TSH (0.5 mU/ml) was lower than expected. Prenalterol, a selective beta 1-agonist, did not stimulate cAMP accumulation, while terbutaline, a selective beta 2-agonist, exerted a potent stimulation. Metoprolol, a selective beta 1-adrenergic blocker, did not affect the response of thyroid follicular cells to isoproterenol. These results demonstrate the existence of beta-adrenergic receptors in human thyroid follicular cells, mainly of the type beta 2, apparently not correlated with TSH receptor. The existence of alpha-adrenergic receptors which counter-regulate TSH functional responses in human thyroid follicular cells is suggested.

Thyroid hormone receptors in human cultured fibroblasts: evidence for cellular T4 transport and nuclear T3 binding.

In cultured normal human skin fibroblasts specific and saturable binding sites for triiodothyronine (T3) have been revealed. In fact radiolabelled T3 binds rapidly to intact cells with maximum uptake after 1 hour, while nuclear binding is delayed, the equilibrium being reached after 2 hours. In intact cells it is possible to identify a single binding site for 125I-T3, with a Ka = 1.8 X 10(10)M-1 and Ro = 1.25 X 10(-11)M, similarly in nuclei it was possible to identify a single binding site of Ka = 8.8 X 10(9)M-1 and Ro = 2.3 X 10(-11)M. Intact human fibroblasts take up thyroxine (T4) even more rapidly than T3, with maximum after 5 min, showing a lower affinity for T4 than for T3 and a negligible specific and saturable binding sites for T4, the presence of a cellular transport system for T4 may be hypothesized, considering that iodothyronine cellular binding is increased by preincubation with low doses of T4.

Reduced mitogenic action of insulin evaluated as 3H-thymidine uptake in diabetic cultured fibroblasts.

As cultured diabetic fibroblasts have a shorter lifespan than normal subjects, the mitogenic activity of foetal calf serum (FCS) and insulin have been studied by taking skin biopsies from 5 patients with juvenile onset diabetes (JODM), 8 with adult onset diabetes (AODM) and 5 with chemical (latent) diabetes (CDM). In controls a high dose of insulin (20 microgram/ml) produced a tritiated thymidine uptake lower than 10% FCS. At lower doses (0.1 to 1.0 microgram/ml) a dose-dependent uptake was observed. In diabetic fibroblasts 10% FCS produced a lower 3H-thymidine uptake than in controls, with p less than 0.005 in JODM, p less than 0.01 in AODM and p less than 0.01 in CDM. A high dose of insulin produced a lower uptake in patients with JODM (p less than 0.01), AODM (p less than 0.01) and CDM (p less than 0.05) when compared with controls. However, when lower doses of insulin were used, 2 out 5 cases of JODM and 4 out of 8 cases of AODM showed a similar response to controls, while 3H-thymidine uptake was low or absent in the remaining cases, including all those with CDM. This study indicates that a reduced mitogenic action of FCS and insulin exists in many patients affected by clinical or chemical diabetes. Our results suggest, however, that the sensitivity to the two mitogenic factors seems to be dissociated: in fact, while a reduced response to FCS is present in all patients, the response to insulin seems to be correlated to the patient's equilibrium at the time of skin biopsy.

Immunohistochemical detection of EGF and NGF receptors in human olfactory epithelium.

The immunohistochemical localization of EGF and NGF receptors has been studied in the olfactory epithelium of human foetuses from 8 to 12 weeks of age. A positivity for EGF receptor, increasing with the age, was detected in the apical portion of the sensory epithelium. The NGF receptor was well detectable also at 8 weeks and localized both in differentiated olfactory cells and in some basal cells. From primary cultures of olfactory epithelium, a cell clone positive for Enolase, Neurofilaments and S-100 Protein was identified. These cells were shown to be reactive for EGF and NGF receptors. The addition of Retinoic acid to the culture medium induces a morphological differentiation of these cells that become positive for the Olfactory Marker Protein.

Catecholamine, vasoactive intestinal peptide and thyrotrophin-dependent cAMP levels display a different sensitivity to iodothyronines in both normal and pathological human thyroid cells in culture.

As the interactions of iodothyronines on adrenergic and vipergic receptors are not clear, the effect of exogenous T3 and T4 on catecholamine- and VIP-induced cAMP accumulation in human normal thyroid cells after eight days of primary culture has been investigated. To evaluate the effect of endogenous iodothyronines, the response of the adenylate cyclase system to isoprenaline, adrenaline, VIP, and TSH was studied during a 10 d period. T3 and T4 were unable to modify the catecholamine- and VIP-induced cAMP accumulation in human normal thyroid cells after 6-8 days of culture, while the response to TSH was significantly inhibited. In cells cultured from thyrotoxic tissue, the response of the adenylate cyclase system to catecholamines and VIP, during a 10 d primary culture, showed a behaviour similar to controls. TSH responsiveness was negligible up to the fourth day of culture, while in normal cells a response to all the agonists was present from the beginning. In view of the lack of effect of iodothyronines on catecholamine- and VIP-induced cAMP accumulation, and of the superimposable behaviour of the response to catecholamines and VIP in normal and hyperthyroid cells during the first days of culture, we can conclude that iodothyronines do not directly modify the response of the adenylate cyclase system to adrenergic and vipergic stimulation in human thyroid follicular cells. The lack of responsiveness to TSH of cells obtained from hyperthyroid tissue during the first 4 d of culture, associated with normal responsiveness to catecholamines and VIP, points to a possible involvement of biogenic amines and neuropeptides in sustaining such hyperthyroid states.