Effects of Follicle-Stimulating Hormone on Human Sperm Motility In Vitro

To evaluate whether the follicle-stimulating hormone (FSH) receptor (FSHR) is expressed in human spermatozoa and the effects of FSH incubation on sperm function. Twenty-four Caucasian men were recruited. Thirteen patients had asthenozoospermia, and the remaining 11 had normal sperm parameters (controls). After confirming FSHR expression, spermatozoa from patients and controls were incubated with increasing concentrations of human purified FSH (hpFSH) to reassess FSHR expression and localization and to evaluate progressive and total sperm motility, the mitochondrial membrane potential, and protein kinase B (AKT) 473 and 308 phosphorylation. FSHR is expressed in the post-acrosomal segment, neck, midpiece, and tail of human spermatozoa. Its localization does not differ between patients and controls. Incubation with hpFSH at a concentration of 30 mIU/mL appeared to increase FSHR expression mainly in patients. Incubation of human spermatozoa with hpFSH overall resulted in an overall deterioration of both progressive and total motility in patients and controls and worse mitochondrial function only in controls. Finally, incubation with FSH increased AKT473/tubulin phosphorylation to a greater extent than AKT308. FSHR is expressed in the post-acrosomal region, neck, midpiece, and tail of human spermatozoa. Contrary to a previous study, we report a negative effect of FSH on sperm motility and mitochondrial function. FSH also activates the AKT473 signaling pathway.

Nickel oxide nanoparticles exposure as a risk factor for male infertility: "In vitro" effects on porcine pre-pubertal Sertoli cells

Lately, nickel oxide nanoparticles (NiO NPs) have been employed in different industrial and biomedical fields. Several studies have reported that NiO NPs may affect the development of reproductive organs inducing oxidative stress and, resulting in male infertility. We investigated the in vitro effects of NiO NPs on porcine pre-pubertal Sertoli cells (SCs) which undergone acute (24 h) and chronic (from 1 up to 3 weeks) exposure at two subtoxic doses of NiO NPs of 1 μg/ml and 5 μg/ml. After NiO NPs exposure we performed the following analysis: (a) SCs morphological analysis (Light Microscopy); (b) ROS production and oxidative DNA damage, gene expression of antioxidant enzymes (c) SCs functionality (AMH, inhibin B Real-time PCR analysis and ELISA test); (d) apoptosis (WB analysis); (e) pro-inflammatory cytokines (Real-time PCR analysis), and (f) MAPK kinase signaling pathway (WB analysis). We found that the SCs exposed to both subtoxic doses of NiO NPs didn't sustain substantial morphological changes. NiO NPs exposure, at each concentration, reported a marked increase of intracellular ROS at the third week of treatment and DNA damage at all exposure times. We demonstrated, un up-regulation of SOD and HO-1 gene expression, at both concentrations tested. The both subtoxic doses of NiO NPs detected a down-regulation of AMH and inhibin B gene expression and secreted proteins. Only the 5 μg/ml dose induced the activation of caspase-3 at the third week. At the two subtoxic doses of NiO NPs a clear pro-inflammatory response was resulted in an up-regulation of TNF-α and IL-6 in terms of mRNA. Finally, an increased phosphorylation ratio of p-ERK1/2, p-38 and p-AKT was observed up to the third week, at both concentrations. Our results show the negative impact of subtoxic doses NiO NPs chronic exposure on porcine SCs functionality and viability.

Zinc restores functionality in porcine prepubertal Sertoli cells exposed to subtoxic cadmium concentration via regulating the Nrf2 signaling pathway

INTRODUCTION

Among substances released into the environment by anthropogenic activities, the heavy metal cadmium (Cd) is known to induce severe testicular injury causing male subfertility/infertility. Zinc (Zn) is another heavy metal that, unlike Cd, is physiologically present in the testis, being essential for spermatogenesis. We aimed to examine the possibility that 50 µM ZnCl₂ could counteract the toxic effects induced by Cd in an in vitro model of porcine prepubertal Sertoli cells (SCs) exposed to both subtoxic (5 μM) and toxic (10 μM) concentrations of CdCl₂ for 48 h.

MATERIALS AND METHODS

Apoptosis, cell cycle, and cell functionality were assessed. The gene expression of Nrf2 and its downstream antioxidant enzymes, ERK1/2, and AKT kinase signaling pathways were evaluated.

MATERIALS AND RESULTS

We found that Zn, in co-treatment with subtoxic and toxic Cd concentration, increased the number of metabolically active SCs compared to Cd exposure alone but restored SC functionality only in co-treatment with subtoxic Cd concentration with respect to subtoxic Cd alone. Exposure of Cd disrupted cell cycle in SCs, and Zn co-treatment was not able to counteract this effect. Cd alone induced SC death through apoptosis and necrosis in a dose-dependent manner, and co-treatment with Zn increased the pro-apoptotic effect of Cd. Subtoxic and toxic Cd exposures activated the Nrf2 signaling pathway by increasing gene expression of Nrf2 and its downstream genes (SOD, HO-1, and GSHPx). Zn co-treatment with subtoxic Cd attenuated upregulation on the Nrf2 system, while with toxic Cd, the effect was more erratic. Studying ERK1/2 and AKT pathways as a target, we found that the phosphorylation ratio of p-ERK1/2 and p-AKT was upregulated by both subtoxic and toxic Cd exposure alone and in co-treatment with Zn.

DISCUSSION

Our results suggest that Zn could counteract Cd effects by increasing the number of metabolically active SCs, fully or partially restoring their functionality by modulating Nrf2, ERK1/2, and AKT pathways. Our SC model could be useful to study the effects of early Cd exposure on immature testis, evaluating the possible protective effects of Zn.

Effects of Titanium Dioxide Nanoparticles on Porcine Prepubertal Sertoli Cells: An "In Vitro" Study

The increasing use of nanomaterials in a variety of industrial, commercial, medical products, and their environmental spreading has raised concerns regarding their potential toxicity on human health. Titanium dioxide nanoparticles (TiO2 NPs) represent one of the most commonly used nanoparticles. Emerging evidence suggested that exposure to TiO2 NPs induced reproductive toxicity in male animals. In this in vitro study, porcine prepubertal Sertoli cells (SCs) have undergone acute (24 h) and chronic (from 1 up to 3 weeks) exposures at both subtoxic (5 µg/ml) and toxic (100 µg/ml) doses of TiO2 NPs. After performing synthesis and characterization of nanoparticles, we focused on SCs morphological/ultrastructural analysis, apoptosis, and functionality (AMH, inhibin B), ROS production and oxidative DNA damage, gene expression of antioxidant enzymes, proinflammatory/immunomodulatory cytokines, and MAPK kinase signaling pathway. We found that 5 µg/ml TiO2 NPs did not induce substantial morphological changes overtime, but ultrastructural alterations appeared at the third week. Conversely, SCs exposed to 100 µg/ml TiO2 NPs throughout the whole experiment showed morphological and ultrastructural modifications. TiO2 NPs exposure, at each concentration, induced the activation of caspase-3 at the first and second week. AMH and inhibin B gene expression significantly decreased up to the third week at both concentrations of nanoparticles. The toxic dose of TiO2 NPs induced a marked increase of intracellular ROS and DNA damage at all exposure times. At both concentrations, the increased gene expression of antioxidant enzymes such as SOD and HO-1 was observed whereas, at the toxic dose, a clear proinflammatory stress was evaluated along with the steady increase in the gene expression of IL-1α and IL-6. At both concentrations, an increased phosphorylation ratio of p-ERK1/2 was observed up to the second week followed by the increased phosphorylation ratio of p-NF-kB in the chronic exposure. Although in vitro, this pilot study highlights the adverse effects even of subtoxic dose of TiO2 NPs on porcine prepubertal SCs functionality and viability and, more importantly, set the basis for further in vivo studies, especially in chronic exposure at subtoxic dose of TiO2 NPs, a condition closer to the human exposure to this nanoagent.

Sperm-carried IGF2 downregulated the expression of mitogens produced by Sertoli cells: A paracrine mechanism for regulating spermatogenesis?

INTRODUCTION

Insulin-like growth factor 2 (IGF2) mRNA has been found in human and mouse spermatozoa. It is currently unknown whether the IGF2 protein is expressed in human spermatozoa and, if so, its possible role in the cross-talk between germ and Sertoli cells (SCs) during spermatogenesis.

METHODS

To accomplish this, we analyzed sperm samples from four consecutive Caucasian men. Furthermore, to understand its role during the spermatogenetic process, porcine SCs were incubated with increasing concentrations (0.33, 3.33, and 10 ng/mL) of recombinant human IGF2 (rhIGF2) for 48 hours. Subsequently, the experiments were repeated by pre-incubating SCs with the non-competitive insulin-like growth factor 1 receptor (IGF1R) inhibitor NVP-AEW541. The following outcomes were evaluated: 1) Gene expression of the glial cell-line derived neurotrophic factor (GDNF), fibroblast growth factor 2 (FGF2), and stem cell factor (SCF) mitogens; 2) gene and protein expression of follicle-stimulating hormone receptor (FSHR), anti-Müllerian hormone (AMH), and inhibin B; 3) SC proliferation.

RESULTS

We found that the IGF2 protein was present in each of the sperm samples. IGF2 appeared as a cytoplasmic protein localized in the equatorial and post-acrosomal segment and with a varying degree of expression in each cell. In SCs, IGF2 significantly downregulated GDNF gene expression in a concentration-dependent manner. FGF2 and SCF were downregulated only by the highest concentration of IGF2. Similarly, IGF2 downregulated the FSHR gene and FSHR, AMH, and inhibin B protein expression. Finally, IGF2 significantly suppressed the SC proliferation rate. All these findings were reversed by pre-incubation with NVP-AEW541, suggesting an effect mediated by the interaction of IGF2 with the IGFR.

CONCLUSION

In conclusion, sperm IGF2 seems to downregulate the expression of mitogens, which are known to be physiologically released by the SCs to promote gonocyte proliferation and spermatogonial fate adoption. These findings suggest the presence of paracrine regulatory mechanisms acting on the seminiferous epithelium during spermatogenesis, by which germ cells can influence the amount of mitogens released by the SCs, their sensitivity to FSH, and their rate of proliferation.

Effect of EPA on Neonatal Pig Sertoli Cells "In Vitro": A Possible Treatment to Help Maintain Fertility in Pre-Pubertal Boys Undergoing Treatment With Gonado-Toxic Therapies

The incidence of cancer in pre-pubertal boys has significantly increased and, it has been recognized that the gonado-toxic effect of the cancer treatments may lead to infertility. Here, we have evaluated the effects on porcine neonatal Sertoli cells (SCs) of three commonly used chemotherapy drugs; cisplatin, 4-Hydroperoxycyclophosphamide and doxorubicin. All three drugs induced a statistical reduction of 5-hydroxymethylcytosine in comparison with the control group, performed by Immunofluorescence Analysis. The gene and protein expression levels of GDNF, were significantly down-regulated after treatment to all three chemotherapy drugs comparison with the control group. Specifically, differences in the mRNA levels of GDNF were: 0,8200 ± 0,0440, 0,6400 ± 0,0140, 0,4400 ± 0,0130 fold change at 0.33, 1.66, and 3.33μM cisplatin concentrations, respectively (**p < 0.01 at 0.33 and 1.66 μM vs SCs and ***p < 0.001 at 3.33μM vs SCs); 0,6000 ± 0,0340, 0,4200 ± 0,0130 fold change at 50 and 100 μM of 4-Hydroperoxycyclophosphamide concentrations, respectively (**p < 0.01 at both these concentrations vs SCs); 0,7000 ± 0,0340, 0,6200 ± 0,0240, 0,4000 ± 0,0230 fold change at 0.1, 0.2 and 1 µM doxorubicin concentrations, respectively (**p < 0.01 at 0.1 and 0.2 μM vs SCs and ***p < 0.001 at 1 μM vs SCs). Differences in the protein expression levels of GDNF were: 0,7400 ± 0,0340, 0,2000 ± 0,0240, 0,0400 ± 0,0230 A.U. at 0.33, 1.66, and 3.33μM cisplatin concentrations, respectively (**p < 0.01 at both these concentrations vs SCs); 0,7300 ± 0,0340, 0,4000 ± 0,0130 A.U. at 50 and 100 μM of 4- Hydroperoxycyclophosphamide concentrations, respectively (**p < 0.01 at both these concentrations vs SCs); 0,6200 ± 0,0340, 0,4000 ± 0,0240, 0,3800 ± 0,0230 A.U. at 0.l, 0.2 and 1 µM doxorubicin concentrations, respectively (**p < 0.01 at 0.1 and 0.2 μM vs SCs and ***p < 0.001 at 1 μM vs SCs). Furthermore, we have demonstrated the protective effect of eicosapentaenoic acid on SCs only at the highest concentration of cisplatin, resulting in an increase in both gene and protein expression levels of GDNF (1,3400 ± 0,0280 fold change; **p < 0.01 vs SCs); and of AMH and inhibin B that were significantly recovered with values comparable to the control group. Results from this study, offers the opportunity to develop future therapeutic strategies for male fertility management, especially in pre-pubertal boys.

Effects of nicotine on porcine pre-pupertal sertoli cells: An in vitro study

Smoke components, such as nicotine and its major metabolites, cross the blood-testis barrier and are detectable in the seminal plasma of both active smokers and individuals exposed to cigarette smoke. In vivo studies in a rat model have further demonstrated that nicotine exposure reduces the weight of the testis, as well as the number of spermatocytes and spermatids, and affects the ultrastructure of Sertoli cells (SC) - which serve as sentinels of spermatogenesis - causing intense germ cell sloughing in the tubular lumen that compromises offspring fertility. This study sought to determine the effects of nicotine on the viability and function of purified pig pre-pubertal SC. Nicotine exposure reduced the mRNA expression and protein levels of anti-Mullerian hormone (AMH) and inhibin B and impaired FSH-r sensitivity via the downregulation of FSH-r and aromatase gene expression compared to untreated SC. Overall, our study suggests that nicotine can significantly alter extracellular matrix and tight junction protein gene expression (e.g., laminin, integrin, and occludin), thus compromising cross-talk between the interstitial and tubular compartments and enhancing blood-testis barrier (BTB) permeability via downregulation of the mitogen-activated protein kinase (MAPK) pathway. These findings further elucidate a potential mechanism of action underlying nicotine exposure's detrimental effects on SC function in vivo.

"In vitro" Effect of Different Follicle-Stimulating Hormone Preparations on Sertoli Cells: Toward a Personalized Treatment for Male Infertility

Follicle-stimulating hormone (FSH), a major regulator of spermatogenesis, has a crucial function in the development and function of the testis and it is extensively given as a fertility treatment to stimulate spermatogenesis. We analyzed the effects of different FSH preparations (α-follitropin, β-follitropin, and urofollitropin) in combination with testosterone on porcine pre-pubertal Sertoli cells. To study the effect of the different FSH treatments in the Sertoli cell function we performed Real Time PCR analysis of AMH, inhibin B, and FSH-r, an ELISA assay for AMH and inhibin B, and a high-throughput comparative proteomic analysis. We verified that all three preparations induced a reduction of AMH in terms of mRNA and secreted proteins, and an increase of inhibin B in terms of mRNA in all the FSH formulations, while solely α-follitropin produced an increase of secreted inhibin B in the culture medium. Comparative proteomic analysis of the three FSH preparations identified 46 proteins, 11 up-regulated and 2 down-regulated. Surprisingly, the combination of testosterone with β-follitropin specifically induced an up-regulation of eight specific secreted proteins. Our study, showing that the three different FSH preparations induce different effects, could offer the opportunity to shed light inside new applications to a personalized reproductive medicine.

In "Vitro" Lps-Stimulated Sertoli Cells Pre-Loaded With Microparticles: Intracellular Activation Pathways

Sertoli cells (SC) are immune privileged cells with the capacity of modulating the immune response by expressing several immune-regulatory factors. SC have the capacity to respond to external stimuli through innate phagocytic and antibacterial activities. This evidence evoked a potential role of SC as drug carriers and therapeutic agents. Such stimuli drive SC towards a still unknown evolution, the clinical relevance of which as yet remains undisclosed. This study sought to investigate the effects of external stimuli in the form of polymeric microparticles (MP) and bacteria derived endotoxins, such as lipopolysaccharides (LPS), in order to identify the pathways potentially involved in cell phenotype modifications. Compared to single stimulation, when combined, MP and LPS provoked a significant increase in the gene expression of IDO, PD-L1, FAS-L, TLR-3, TLR-4, MHC-II, ICAM-1, TFGβ1, BDF123, BDF129, BDF3 and pEP2C. Western Blotting analysis demonstrated up-regulation of the ERK 1-2 and NF-kB p65 phosphorylation ratios. Our study, showing the exponential increase of these mediators upon combined MP and LPS stimulation, suggests a "switch" of SC function from typical cells of the blood-testicular barrier to nonprofessional tolerogenic antigen-presenting cells. Further studies should target the clinical and technological implications of such stimuli-induced SC transformation.

Effects of Insulin on Porcine Neonatal Sertoli Cell Responsiveness to FSH In Vitro

There is ongoing debate as to whether the decline of sperm production in recent times may be related to a parallel increase in the rate of obesity and diabetes. Lower anti-Müllerian hormone (AMH) and inhibin B secretion have been observed in young hyperinsulinemic patients compared to healthy controls, suggesting a Sertoli cell (SC) dysfunction. The pathophysiological mechanisms underlying SC dysfunction in these patients are poorly understood. To the best of our knowledge, no evidence is available on the effects of insulin on SC function. Therefore, this study was undertaken to assess the effects of insulin on basal and follicle-stimulating hormone (FSH)-stimulated SC function in vitro. To accomplish this, we evaluated the expression of AMH, inhibin B and FSHR genes, the secretion of AMH and inhibin B and the phosphorylation of AKT473 and SC proliferation on neonatal porcine SC after incubation with FSH and/or insulin. We found that similar to FSH, the expression and secretion of AMH is suppressed by insulin. Co-incubation with FSH and insulin decreased AMH secretion significantly more than with FSH alone. Insulin had no effect on the expression and secretion of the inhibin B gene, but co-incubation with FSH and insulin had a lower effect on inhibin B secretion than that found with FSH alone. FSH and/or insulin increased AKT473 phosphorylation and SC proliferation. In conclusion, the results of this study showed that insulin modulates SC function. We hypothesize that hyperinsulinemia may therefore influence testicular function even before puberty begins. Therefore, particular care should be taken to avoid the onset of hyperinsulinemia in children to prevent a future deleterious effect on fertility.

The IGF1 Receptor Is Involved in Follicle-Stimulating Hormone Signaling in Porcine Neonatal Sertoli Cells

Experimental evidence has shown that the IGF1 receptor (IGF1R) is involved in testicular development during embryogenesis. More recently, data gathered from mice granulosa cells and zebrafish spermatogonia suggest that IGF1R has a role in Follicle-stimulating hormone (FSH) signaling. No evidence has been reported on this matter in Sertoli cells (SCs) so far. The aim of the study was to evaluate the role, if any, of the IGF1R in FSH signaling in SCs. The effects of FSH exposure on myosin-phosphatase 1 (MYPT1), ERK 1/2, AKT³⁰⁸, AKT⁴⁷³, c-Jun N-terminal kinase (JNK) phosphorylation and on anti-Müllerian hormone (AMH), inhibin B and FSH receptor (FSHR) mRNA levels were assessed with and without the IGF1R inhibitor NVP-AEW541 in purified and functional porcine neonatal SCs. Pre-treatment with NVP-AEW541 inhibited the FSH-induced MYPT1 and ERK 1/2 phosphorylation, decreased the FSH-dependent Protein kinase B (AKT)³⁰⁸ phosphorylation, but did not affect the FSH-induced AKT⁴⁷³ and JNK phosphorylation rate. It also interfered with the FSH-induced AMH and FSHR down-regulation. No influence was observed on the FSH-stimulated Inhibin B gene expression. Conclusion. These findings support the role of theIGF1R in FSH signaling in porcine SCs. The possible influence of IGF1 stimulation on the FSH-mediated effects on SCs should be further explored.

An in vitro prototype of a porcine biomimetic testis-like cell culture system: a novel tool for the study of reassembled Sertoli and Leydig cells

At present, there is no reliable in vitro assembled prepubertal testis-like biomimetic organ culture system designed to assess the functional effects of human gonadotropins on Sertoli and Leydig cells. Spermatogenesis is regulated by endocrine, paracrine, and juxtacrine factors (testicular cross-talk), mainly orchestrated by gonadotropins such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH) that play a pivotal role by stimulating Leydig and Sertoli cells, respectively. The aim of our study was to set up an in vitro prepubertal porcine bioengineered construct as a new model for experimental studies on reassembled Sertoli and Leydig cells. We have evaluated Sertoli and Leydig cells obtained from 15- to 20-day-old neonatal pig testes in terms of purity and function. Subsequently, purified Sertoli and enriched Leydig cells were subjected to coincubation to obtain an in vitro prepubertal porcine testis-like culture system. We performed enzyme-linked immunosorbent assay (ELISA) for anti-Müllerian hormone (AMH), inhibin B, and testosterone secretion in the medium, and Real-Time PCR analysis of AMH, inhibin B, FSH-r, aromatase, LHr, and 3β-HSD mRNA expression levels. This in vitro testis-like system was highly responsive to the effects of human gonadotropins and testosterone. AMH mRNA expression and secretion declined, and inhibin-B increased, while FSH-receptor expression was downregulated upon FSH/LH exposure/treatment. Finally, the production of testosterone was increased selectively upon LH treatment. In summary, our proposed model could help to better determine the action of human gonadotropins on Sertoli and Leydig cells. The potential usefulness of the system for shedding light into male infertility-related issues is evident.

Long-term stability, functional competence, and safety of microencapsulated specific pathogen-free neonatal porcine Sertoli cells: a potential product for cell transplant therapy

BACKGROUND

Porcine Sertoli cells (pSCs) have been employed for cell therapy in pre-clinical studies for several chronic/immune diseases as they deliver molecules associated with trophic and anti-inflammatory effects. To be employed for human xenografts, pSCs products need to comply with safety and stability. To fulfill such requirements, we employed a microencapsulation technology to increase pre-transplant storage stability of specific pathogen-free pSCs (SPF-pSCs) and evaluated the in vivo long-term viability and safety of grafts.

METHODS

Specific pathogen free neonatal pigs underwent testis excision under sterility. pSCs were isolated, characterized by immunofluorescence (IF) and cytofluorimetric analysis (CA) and examined in terms of viability and function [namely, production of anti-müllerian hormone (AMH), inhibin B, and transforming growth factor beta-1 (TFGβ-1)]. After microencapsulation in barium alginate microcapsules (Ba-MC), long-term SPF-pSCs (Ba-MCpSCs) viability and barium concentrations were evaluated at 1, 24 throughout 40 h to establish pre-transplant storage conditions.

RESULTS

The purity of isolated pSCs was about 95% with negligible contaminating cells. Cultured pSCs monolayers, both prior to and after microencapsulation, maintained high function and full viability up to 24 h of storage. At 40 h post-encapsulation, pSCs viability decreased to 80%. Barium concentration in Ba-MCpSCs lagged below the normal maximum daily allowance and was stable for 4 months in mice with no evident side effects.

CONCLUSIONS

Such results suggest that this protocol for the isolation and microencapsulation of pSCs is compatible with long-haul transportation and that Ba-MCpSCs could be potentially employable for xenotransplantation.

Craniofacial asymmetry in non-syndromic orthodontic subjects: clinical and postural evaluation

OBJECTIVE

The aim of this study was to evaluate the possible influence of a malocclusion pattern on a patient's posture.

METHODS

Patients affected by symmetric malocclusion or malocclusion with mild to moderate non-syndromic craniofacial asymmetry were submitted to a clinical and X-ray evaluation. Subjects with symmetric skeletal class I were used as the control group. Evaluation of differences in postural pattern was performed using rasterstereography.

RESULTS

Statistical analysis (t-test) was performed on 61 patients divided in homogeneous subgroups. The results show a pelvic torsion angle of 1.08° + 3.00° (P = 0.0023) (normal value (NV) = 0.0-1.9°) in subjects presenting skeletal class II z asymmetry (control group: 1.17° ± 1.25°, not significant (NS)).

CONCLUSIONS

The present study shows evidence of a relationship between malocclusion and spinal posture. A better understanding of the relationship between malocclusion and posture may help in planning a multidisciplinary approach that could involve other specialists.

Toxicity of cadmium on Sertoli cell functional competence: an in vitro study

Cadmium (Cd), an ubiquitous environmental metal, mainly used for industrial purposes, may be toxic at level of the reproductive system. Testis tubular-based Sertoli cells (SC), play a major role in constituting the blood-testis barrier and provide a unique microenvironment for the genesis and differentiation of germ cells. Hence SC strictly control sperm qualitative and quantitative parameters. We aimed to assess whether exposure to Cd would adversely affect superior mammal SC viability and function. We isolated and purified SC from pre-pubertal pig testes according to our method and incubated the retrieved cells with three different Cadmium chloride concentrations (5-10-15 microM). Parameters of SC function such as inhibin B and anti-Mullerian hormone (AMH) were depressed by Cd exposure, contrary to what observed in untreated controls. No impairment of the FSH receptor integrity on the SC, as assessed by 17-beta-estradiol production, upon stimulation with FSH, was observed in either 5 microM Cd-treated or untreated controls. Differences, on the contrary, were observed for higher Cd concentrations (10 and 15 mM), in terms of FSH receptor integrity, that was altered, as compared to untreated controls, in terms of lower production of 17-beta-estradiol. In addition, the apoptotic test showed a significant increase of early (ANNEXIN V-/Propidium Iodide+) (AV-/PI+) and late apoptotic cells (AV+/ PI+) in all Cd -treated SC conditions as compared to controls. In conclusion, the Cd -related toxicity on SC, clearly demonstrated by our study, even at low concentrations, is expected to damage spermatogenesis that directly is dependent upon retention of SC viability and function.

Silica particle size and shape: in vitro effects on extracellular matrix metabolism and viability of human bronchial epithelial cells

Crystal micro-morphology and dimension of silica particles could be responsible for the high prevalence of silicosis as recently found among goldsmiths. In the present study we investigated two samples of silica particles with different surface sizes and shapes for their capacity to induce changes in ECM component production. In addition we investigated if their different effects could be related to cytotoxicity and apoptotic effects. Human bronchial epithelial cells were cultured with or without a sample of Silica used for casting gold jewellery, named in our experiments Silica P or a commercial sample of Silica with different physical and chemical properties, named in our experiments Silica F. After 48 h of exposure PCR analysis determined levels of several matrix components. As induction of the apoptosis cascade, annexin assay, caspase 3 activity and cellular cytoxicity by MTT assay were assayed. Silica F promoted fibronectin, MMP12, tenascin C and Integrins b5 gene expressions more than Silica P. Silica P stimulated more TGF&#223;1 and its TGF&#223;R1 receptor than Silica F. Cytotoxic effects were induced by the two samples of Silica. On the contrary, no alteration in classic apoptotic marker protein expression was observed in presence of either Silica F or Silica P, suggesting silica particles affect ECM production and metalloproteases through a mechanism that does not involve apoptotic activation. Different Silica micromorphology and TGF&#223; signal pathway are linked to lung fibrotic effects but the potential role Silica in apoptotic and toxic reaction remains to be ascertained.

Human cleft lip and palate fibroblasts and normal nicotine-treated fibroblasts show altered in vitro expressions of genes related to molecular signaling pathways and extracellular matrix metabolism

Nonsyndromic cleft lip with or without cleft palate (CLP) is a frequent craniofacial malformation caused by both genetic and environmental factors. Maternal smoking during pregnancy is a known risk factor, due to the teratogenic role of nicotine. To assess and compare the impact of CLP and nicotine, we studied the quantitative expression of genes involved in signaling pathways and extracellular matrix (ECM) metabolism in human normal nicotine-treated (NicN) and CLP fibroblasts compared to normal control (CTRL) cells. Palatal fibroblast cultures from seven CLP children and seven age-matched CTRL subjects were established and subconfluent cells incubated for 24 h without (CTRL and CLP fibroblasts) or with (NicN fibroblasts) 0.6 mM nicotine. Gene expressions were analyzed by real-time quantitative PCR. For the first time, a regulated cholinergic signaling in our human fibroblasts in vitro was demonstrated. Members of TGF-beta, retinoic acid (RA), and GABA-ergic signaling systems were also differently regulated. Among the ECM genes, fibronectin, syndecan, integrin alpha2, and MMP13 genes were concordantly modulated, while integrin beta5, and decorin genes were discordantly modulated. Interestingly, nicotine treatment regulated gene expressions of CD44 and CLPTM1, two candidate genes for CLP. Our findings show a positive association between nicotine treatment and CLP phenotype. Results suggest that nicotine deranges normal palate development, which might contribute to the development of a CLP malformative phenotype, through the impairment of some important signaling systems and ECM composition.

Differences in extracellular matrix production and basic fibroblast growth factor response in skin fibroblasts from sporadic and familial Alzheimer's disease

Extracellular matrix (ECM) molecules and growth factors, such as fibroblast growth factor (FGF), play a crucial role in Alzheimer's disease (AD). The purpose of this investigation was to determine whether phenotypic alterations in ECM production are present in non-neuronal AD cells associated with different FGF expression and response. Synthesis of glycosaminoglycans (GAG) and collagen were measured in skin fibroblasts from patients with familial, sporadic AD (FAD and SAD respectively), and from age-matched controls by radiolabeled precursors. Proteoglycans (PG), metalloprotease (MMP)-1, and FGF gene expressions were measured by reverse transcription-polymerase chain reaction. The results showed different ECM neosynthesis and mRNA levels in the two AD fibroblast populations. FAD accumulated more collagen and secreted less GAG than SAD. Biglycan PG was upregulated in FAD while betaglycan, syndecan, and decorin were markedly downregulated in SAD fibroblasts. We found a significant decrease of MMP1, more marked in FAD than in SAD fibroblasts. Constitutive FGF expression was greatly reduced in both pathological conditions (SAD>FAD). Moreover, an inverse high affinity/low affinity FGF receptor ratio between SAD and FAD fibroblasts was observed. FGF treatment differently modulated ECM molecule production and gene expression in the two cell populations. These observations in association with the changes in FGF gene expression and in the FGF receptor number, suggest that cellular mechanisms downstream from FGF receptor binding are involved in the two different forms of AD.

Toremifene decreases type I, type II and increases type III receptors in desmoid and fibroma and inhibits TGFbeta1 binding in desmoid fibroblasts

Tissue infiltration is different in desmoid and fibroma tumours. Both produce high levels of transforming growth factor beta1 (TGFbeta1), which is related to extracellular matrix (ECM) accumulation which in turn regulates cell function and cell migration. Interactions between collagen, proteoglycans and cell surface fibronectin are involved in the assembly and functions of the ECM. As toremifene inhibits collagen and TGFbeta1 synthesis, we tested it in normal, desmoid and fibroma fibroblasts. We will report the changes in glycosaminoglycan (GAG) and collagen synthesis, TGFbeta1 activity, fibronectin mRNA expression and TGFbeta1 receptors after toremifene treatment in normal, fibroma and desmoid fibroblasts. We evaluated GAG and collagen synthesis with 3H-glucosamine and 3H-proline incorporation, TGFbeta1 activity with the ELISA method, TGFbeta1 receptor affinity with 125I-TGFbeta1 binding and total RNA with Northern blot analysis. GAG and collagen synthesis, TGFbeta1 activity and fibronectin levels were higher in fibroma and desmoid than normal fibroblasts. The increase was greater in desmoid than fibroma tumour cells. Toremifene treatment reduced GAG and collagen synthesis, TGFbeta1 activity and fibronectin levels in all cell cultures. The percentage reduction in GAG was similar in all cultures; the reduction in collagen synthesis and TGFbeta1 activity was the highest in desmoid fibroblasts. TGFbeta1 receptors were higher in fibroma and desmoid cells than controls. Toremifene reduced TGFbeta1 receptors only in desmoid fibroblasts, with no effect on the changes in type I, II, and III receptors. Our data show that toremifene modifies the ECM components that regulate cytokine activity and cell migration. The reduction in receptor number only in desmoid cells suggests that toremifene may reduce TGFbeta1's affinity for its receptors. Synthesis of a substance regulating protein kinase activity, which is directly involved in the link between TGFbeta1 and its receptors, cannot be excluded.

FGF2 effects in periosteal fibroblasts bearing the FGFR2 receptor Pro253 Arg mutation

AIM

A growing number of mutations mapped in the receptor gene for fibroblast growth factor have been implicated in several cranial development disorders including the Apert and Crouzon syndromes. The present paper investigated cellular mechanisms underlying Apert phenotype, by analyzing the effects of FGF2 in primary cultures of Apert periosteal fibroblasts carrying the FGFR2 Pro253Arg mutation.

RESULTS

FGF2 administration significantly decreased extracellular matrix production in mutant cells by stimulating degradative enzymatic activities. Gene expression analysis revealed that decorin and biglycan, two proteoglycans involved in collagen fibrillogenesis, were more expressed in mutant cells and down-regulated by FGF2. FGF2 receptor binding showed little differences in high affinity receptor counts between mutant and wild-type cells, while we showed for the first time that low affinity receptors are significantly fewer in mutant cells. Differences were found in Crouzon syndrome, where both high and low affinity receptor counts were up-regulated.

CONCLUSIONS

The different mutation and low affinity receptor regulation in mutant receptors support the hypothesis that the impact on the activity of the ligand-receptor complex could allow distinct modes of FGF2 activation in Apert and Crouzon syndromes, which interfere with the FGFR2 signalling cascade.

Retinoic acid, GABA-ergic, and TGF-beta signaling systems are involved in human cleft palate fibroblast phenotype

During embryogenesis, a complex interplay between extracellular matrix (ECM) molecules, regulatory molecules, and growth factors mediates morphogenetic processes involved in palatogenesis. Transforming growth factor-beta (TGF-beta), retinoic acid (RA), and gamma-aminobutyric acid (GABA)ergic signaling systems are also potentially involved. Using [3H]glucosamine and [35S]methionine incorporation, anion exchange chromatography, semiquantitative radioactive RT-PCR, and a TGF-beta binding assay, we aimed to verify the presence of phenotypic differences between primary cultures of secondary palate (SP) fibroblasts from 2-year-old subjects with familial nonsyndromic cleft lip and/or palate (CLP-SP fibroblasts) and age-matched normal SP (N-SP) fibroblasts. The effects of RA--which, at pharmacologic doses, induces cleft palate in newborns of many species--were also studied. We found an altered ECM production in CLP-SP fibroblasts that synthesized and secreted more glycosaminoglycans (GAGs) and fibronectin (FN) compared with N-SP cells. In CLP-SP cells, TGF-beta3 mRNA expression and TGF-beta receptor number were higher and RA receptor-alpha (RARA) gene expression was increased. Moreover, we demonstrated for the first time that GABA receptor (GABRB3) mRNA expression was upregulated in human CLP-SP fibroblasts. In N-SP and CLP-SP fibroblasts, RA decreased GAG and FN secretion and increased TGF-beta3 mRNA expression but reduced the number of TGF-beta receptors. TGF-beta receptor type I mRNA expression was decreased, TGF-beta receptor type II was increased, and TGF-beta receptor type III was not affected. RA treatment increased RARA gene expression in both cell populations but upregulated GABRB3 mRNA expression only in N-SP cells. These results show that CLP-SP fibroblasts compared with N-SP fibroblasts exhibit an abnormal phenotype in vitro and respond differently to RA treatment, and suggest that altered crosstalk between RA, GABAergic, and TGF-beta signaling systems could be involved in human cleft palate fibroblast phenotype.

Retinoic acid, GABA-ergic, and TGF-beta signaling systems are involved in human cleft palate fibroblast phenotype

During embryogenesis, a complex interplay between extracellular matrix (ECM) molecules, regulatory molecules, and growth factors mediates morphogenetic processes involved in palatogenesis. Transforming growth factor-beta (TGF-beta), retinoic acid (RA), and gamma-aminobutyric acid (GABA)ergic signaling systems are also potentially involved. Using [3H]glucosamine and [35S]methionine incorporation, anion exchange chromatography, semiquantitative radioactive RT-PCR, and a TGF-beta binding assay, we aimed to verify the presence of phenotypic differences between primary cultures of secondary palate (SP) fibroblasts from 2-year-old subjects with familial nonsyndromic cleft lip and/or palate (CLP-SP fibroblasts) and age-matched normal SP (N-SP) fibroblasts. The effects of RA--which, at pharmacologic doses, induces cleft palate in newborns of many species--were also studied. We found an altered ECM production in CLP-SP fibroblasts that synthesized and secreted more glycosaminoglycans (GAGs) and fibronectin (FN) compared with N-SP cells. In CLP-SP cells, TGF-beta3 mRNA expression and TGF-beta receptor number were higher and RA receptor-alpha (RARA) gene expression was increased. Moreover, we demonstrated for the first time that GABA receptor (GABRB3) mRNA expression was upregulated in human CLP-SP fibroblasts. In N-SP and CLP-SP fibroblasts, RA decreased GAG and FN secretion and increased TGF-beta3 mRNA expression but reduced the number of TGF-beta receptors. TGF-beta receptor type I mRNA expression was decreased, TGF-beta receptor type II was increased, and TGF-beta receptor type III was not affected. RA treatment increased RARA gene expression in both cell populations but upregulated GABRB3 mRNA expression only in N-SP cells. These results show that CLP-SP fibroblasts compared with N-SP fibroblasts exhibit an abnormal phenotype in vitro and respond differently to RA treatment, and suggest that altered crosstalk between RA, GABAergic, and TGF-beta signaling systems could be involved in human cleft palate fibroblast phenotype.

Desmoid and fibroma tumors differently respond to TGFβ1 stimulus and ECM macromolecule accumulation

Desmoid and fibroma tumours are characterized by cell proliferation, glycosaminoglycan and collagen fibre accumulation, high levels of transforming growth factor beta(1) (TGFbeta(1)) and different patterns of tissue infiltration. TGFbeta(1) is related to extracellular matrix (ECM) composition which, in turn, regulates cell functions and cell migration. In this study we report changes in cell proliferation, glycosaminoglycan (GAG) and collagen synthesis, TGFbeta(1) mRNA expression and fibronectin levels in normal, desmoid and fibroma fibroblast cultures before and after TGFbeta(1) stimulation. Our data showed cell proliferation, GAG and collagen synthesis, transforming growth factor beta(1) mRNA expression and fibronectin levels were significantly higher in desmoid than in fibroma cultures. TGFbeta(1) treatment had no effect on cell proliferation, but increased TGFbeta(1) mRNA expression, GAG, fibronectin and collagen synthesis in desmoid and fibroma fibroblasts. Its effects were more marked in desmoid cells. Fibronectin favours cell migration, while changes in GAG composition alter cell behaviour and ECM organization. In conclusion our data suggest that the different patterns of infiltration in desmoid and fibroma tumours are due to changes in ECM components and cell-ECM interactions which can be ascribed to altered TGFbeta(1) mRNA expression and TGFbeta(1) activity.

Lung regions differently modulate bronchial branching development and extracellular matrix plays a role in regulating the development of chick embryo whole lung

Normal branching development is dependent on the correlation between cells and extracellular matrix. In this interaction glycosaminoglycans, cytokines and growth factors play a fundamental role. In order to verify the distribution and influence of extracellular matrix and related enzymes on chick embryo lung development, 6 day-old whole lungs were maintained in vitro with testicular hyaluronidase, beta-N-acetyl-D-glucosaminidase and chondrotinase ABC or in linkage with apical, medial and caudal lung regions of 6-day development before and after enzyme treatment. In a separate lung region beta-N-acetyl-D-glucosaminidase and hyaluronidase were determined. Our data show that the whole lung cultures increase bronchial branching development when the medial region is admixed separately, while the separate apical or caudal regions or apical combined with caudal region do not affect bronchial branching development. The enzyme treatment of medial region prevents the branching development in associated whole lung. The bronchial branching development of whole lung cultured in medium containing the enzymes related to glycosaminoglycans turnover is significantly altered. In conclusion, these data show that the different influence of separate apical, medial, caudal lung regions on bronchial branching development is related to the extracellular matrix composition.

Comparative in vitro studies on the fibrogenic effects of two samples of silica on epithelial bronchial cells

The small dimension and particle shape of silica in gypsum used to prepare moulds for lost wax casting might be responsible for the high prevalence of silicosis in gold jewellery. To test this hypothesis, human pulmonary epithelial cell (BEAS-2B) cultures were exposed to two samples of silica with different crystal micro-morphologies: Silica Powder (Silica P) which is used in casting gold jewellery, and no powder Silica (Silica F). Extracellular matrix (ECM) production was evaluated using radio-labelled precursors and quantified by RT-PCR analysis. Expression of basic fibroblast growth factor (FGF2) and its receptor (FGFR2) was also evaluated. The results demonstrated Silica P particles had a very fine lamellar crystalline structure while Silica F was characterized by larger rounded crystals. Silica P stimulated collagen production significantly more than Silica F and downregulated laminin and metalloprotease expression. Both silica samples down-regulated FGF2 but only Silica F enhanced FGF2 receptor expression. In conclusion each Silica sample promoted a profibrotic lung microenvironment in a different manner and also elicited different FGF2 signalling pathways. The data confirm that different micromorphology of Silica particles affects the fibrogenic potential and the molecular mechanisms of dust pathogenicity.

Effect of titanium surface roughness on human osteoblast proliferation and gene expression in vitro

PURPOSE

Cell proliferation and extracellular matrix formation are primary events in bone formation. At the dental implant-tissue interface, implant surface roughness modulates osteoblast functions. The aim of the present in vitro study was to investigate the effect of varying surface roughness of titanium implant material on cell proliferation and mRNA expression of specific markers of osteoblast phenotype.

MATERIALS AND METHODS

Primary cultures of osteoblasts derived from human mandibular bone were cultured on titanium surfaces. Three titanium surfaces were studied: machined titanium, microsandblasted titanium, and macro-sandblasted titanium (average surface roughnesses of 0.5 and 3 microm, respectively). Cell morphology was estimated by scanning electron microscope analysis and cell proliferation by measuring the amount of 3H-thymidine incorporation into DNA. mRNA expression of osteonectin, osteopontin, bone sialoprotein (BSP), and Runx2, which are markers of osteoblastic phenotype, were determined by reverse transcriptase polymerase chain reaction (RT-PCR) analysis.

RESULTS

Human osteoblasts cultured on machined titanium spread more and were flatter than cells cultured on rough titanium. All blasted surfaces showed significantly higher DNA synthesis than the machined surfaces. Osteonectin mRNA expression was similar on all surfaces. Other mRNA transcripts were increased in osteoblasts cultured on rough titanium surfaces, particularly the macrosandblasted surface.

CONCLUSIONS

An average surface roughness of 3 microm (macro-sandblasted titanium) is more suitable than an average surface roughness of 0.5 microm (micro-sandblasted titanium) in favoring osteoblast differentiation in vitro.

In vitro human osteoblast and extracellular matrix changes after transforming growth factor beta 1 treatment

AIMS

Normal bone tissue is characterised by a balancing of osteoblast and osteoclast activity. The activity and differentiation of these cells are regulated by vitamins, hormones and cytokines. The action of these factors on bone tissue cells depends on the composition and mineralisation of extracellular bone matrix. In particular, transforming growth factor beta 1 (TGFbeta1) acts on collagen fibres, glycosaminoglycan secretion and on the enzymes correlated to the turnover of glycosaminoglycans. The normal functions of bone tissue also depend on its mineralisation, which is highly altered in the process of uraemia.

METHODS

In this study, we analysed in vitro the effect of transforming growth factor beta on osteoblast proliferation, collagen synthesis and glycosaminoglycan secretion with 3H-thymidine, 3H-proline or 3H-glucosamine incorporation, and on enzymes, such as beta-N-acetyl-D-glucosaminidase and beta-glucuronidase, involved in extracellular matrix turnover. Moreover, phosphatase alkaline activity and osteocalcin related to mineralisation of extracellular matrix were determined.

RESULTS

Our data show that TGFbeta1 significantly decreases 3H-thymidine and 3H-proline incorporation and increases (p < or = 0.01) extracellular sulphated glycosaminoglycan synthesis. It also increases osteocalcin levels, phosphatase alkaline, beta-N-acetyl-D-glucosaminidase and beta-glucoronidase activities.

CONCLUSION

TGFbeta1 changes the synthesis of extracellular matrix components by osteoblasts. These variations favour the action of cytokine and osteoclasts. Since the TGFbeta1 accumulates in bone tissue and increases during uraemia, with due limitations this action leads to an imbalance between synthesis and degradation and could explain bone alterations in uraemic patients.

P253R fibroblast growth factor receptor-2 mutation induces RUNX2 transcript variants and calvarial osteoblast differentiation

Unregulated fibroblast growth factor 2 (FGF2) signaling caused by mutations in the fibroblast growth factor receptor (FGFR2) leads to human craniosynostosis such as the Apert syndrome. In an in vitro control model of calvarial osteoblasts from Apert patients carrying the FGFR2 P253R mutation, we studied the changes in cellular phenotype and evaluated the effects of FGF2. Compared with wild-type controls, osteocalcin mRNA was down-regulated in Apert osteoblasts, Runt-related transcription factor-2 (RUNX2) mRNA was differentially spliced, and FGF2 secretion was greater. Total protein synthesis, fibronectin and type I collagen secretion were up-regulated, while protease and glycosidase activities and matrix metalloproteinase-13 (MMP-13) transcription were decreased, suggesting an altered ECM turnover. Adding FGF2 increased protease and glycosidase activities and down-regulated fibronectin and type I collagen secretion in Apert osteoblasts. High affinity FGF2 receptors were up-regulated in Apert osteoblasts and analysis of signal transduction showed elevated levels of Grb2 tyrosine phosphorylation and the Grb2-p85 beta association, which FGF2 stimulation strongly reduced. All together these findings suggest increased constitutive receptor activity in Apert mutant osteoblasts and an autocrine loop involving the FGF2 pathway in modulation of Apert osteoblast behavior.

Unique human CD133+ leukemia cell line and its modulation towards a mesenchymal phenotype by FGF2 and TGFβ1

Immunological features of GM-490 cells, a new blood cell line from a patient with acute lymphoblastic leukemia, included lack of CD34, CD38, CD45, CD14, HLA-DR, and lymphoid and myeloid markers and expression of CD29, CD36, CD44, CD54, CD71, CD105, and CD133. Molecular analysis indicated CD45 gene expression was absent but CD34 mRNA was present. GM-490 cells constitutively produced fibronectin (FN), type III and traces of type I collagen, collagenases, glycosaminoglycans (GAG) and biglycan and betaglycan proteoglycans (PG) as well as FGF2 and TGFbeta1. When FGF2 and/or TGFbeta1 were added to cells in vitro, they stimulated cell proliferation and differently modulated matrix production and growth factor receptor expression. Reverse transcription-polymerase chain reaction (RT-PCR) detection of transcripts encoding for osteocalcin and RUNX2 suggests GM-490 cells differentiate towards the osteoblast pathway. GM-490 cells expressed the low affinity nerve growth factor receptor (p75LNGFR), a somatic stem cell marker that is not detected in hematopoietic cells, leading to the hypothesis that GM-490 has mesenchymal stem cell properties. The reciprocal modulating effects of FGF2 and TGFbeta1 on each other's receptors make the GM-490 cell line a new model for investigating the relationship between these growth factors and their receptors in autocrine loops which are believed to sustain the malignant clone in hematological diseases.

Bronchial branching correlates with specific glycosidase activity, extracellular glycosaminoglycan accumulation, TGF beta(2), and IL-1 localization during chick embryo lung development

During organ differentiation, cell-extracellular matrix (ECM) interactions are required. The components of the ECM, such as glycosaminoglycans, fibronectin, laminin, and collagens, change in relation to cytokine and enzyme activity. Moreover, glycosaminoglycans (GAGs) are components of the ECM that play an important role in both cytokine regulation and cell activities. In this work we studied the accumulation of hyaluronic acid and chondroitin sulfate and heparan sulfate proteoglycans (PGs), beta-N-acetyl-D-glucosaminidase activity, the presence of transforming growth factor beta(2) (TGF beta(2)), and interleukin-1 (IL-1), and the localization of fibronectin, laminin, and collagen I and IV during the early stages of chick embryo lung development. We also determined the levels of hyaluronic acid, chondroitin sulfate, dermatan sulfate, and heparan sulfate GAGs and the activity of beta-N-acetyl-D-glucosaminidase with biochemical methods. Our data show that beta-N-acetyl-D-glucosaminidase activity increases in each cell, especially in the epithelial growth front at the emergence of each bronchial bud, where hyaluronic acid and IL-1 are located in the surrounding mesenchymal areas. Chondroitin sulfate and heparan sulfate PGs, fibronectin, laminin, and collagen I and IV are evident in the area near the basal membrane along the sides where the forming structures are stabilized. Biochemical data show that beta-N-acetyl-D-glucosaminidase activity increases in cells during lung development and is related to GAG decrease and to modifications of the nonsulfated/sulfated GAG ratio. These modifications could change cytokine activity and play an important role in bronchial branching development.

Biocompatibility of collagen membranes crosslinked with glutaraldehyde or diphenylphosphoryl azide: Anin vitro study

Crosslinking of collagen biomaterials increases their resistance to degradation in vivo. Glutaraldehyde (GA) is normally used to crosslink collagen biomaterial, but is often cytotoxic. Diphenylphosphoryl azide (DPPA) has recently been proposed as reagent, but little is known about its effects on cell behavior. In this study, we determined which collagen membrane was the most biocompatible: Paroguide which is crosslinked with DPPA and contains chondroitin sulfate; Opocrin which is crosslinked with DPPA; Biomed Extend which is crosslinked with GA; and Bio-Gide which is left untreated. Cell proliferation and extracellular matrix macromolecule deposition were evaluated in human fibroblasts cultured on the membranes. The GA-crosslinked Biomed Extend membrane and the not-crosslinked Bio-Gide membrane reduced cell growth and collagen secretion compared with DPPA-crosslinked biomembranes. When Paroguide and Opocrin were compared, better results were obtained with Paroguide. The greatest amount of transforming growth factor beta1, a growth factor involved in extracellular matrix macromolecule accumulation and in tissue regeneration, was produced by cells cultured on Paroguide, with Opocrin second. Our data suggest that the DPPA method is more biocompatible than the GA for crosslinking collagen biomaterials and that membranes made of collagen plus chondroitin sulfate are better than membranes made of pure collagen.

Cross-Talk Between Interleukin-6 and Transforming Growth Factor-β3Regulates Extracellular Matrix Production by Human Fibroblasts from Subjects with Non-Syndromic Cleft Lip and Palate

BACKGROUND

Transforming growth factor-beta (TGF-beta) interference with interleukin 6 (IL-6) activity and the role of the latter in early human embryonic development prompted us to examine the effects IL-6 on matrix synthesis and the effects of TGF-beta3 on IL-6 expression human cleft lip and palate (CLP) fibroblasts.

METHODS

Collagen and glycosaminoglycan (GAG) synthesis were determined by radiolabeled precursors and biglycan expression by Northern blotting before and after adding IL-6. The effects of TGF-beta3 on IL-6 production were assayed by evaluating IL-6 transcript by Northern blotting and IL-6 protein secretion by enzyme-linked immunosorbent assay.

RESULTS

The results showed that IL-6 elicited an inhibitory effect on collagen and GAG levels in CLP fibroblasts by lowering hyaluronan and dermatan sulfate secretion. IL-6 up-regulated biglycan expression, but less strongly than TGF-beta3. TGF-beta3 significantly down-regulated IL-6 transcript and secretion in CLP fibroblasts.

CONCLUSIONS

These data suggest the increase in matrix components that characterize the CLP fibroblast phenotype might be due to a concerted TGF-beta3-IL-6 action. We hypothesize changes in cross-talk between TGF-beta3 and IL-6 signal transduction pathways are involved in the induction of cleft palate.

Biomembranes enriched with TGFbeta1 favor bone matrix protein expression by human osteoblasts in vitro

The use of growth factors in oral tissue regeneration is currently under investigation. When growth factors are combined with commercial materials, the in vitro mechanisms of action still remain unclear. The present study first evaluated the capacity of barrier membranes, used in oral surgery, to sequester TGFbeta(1). Resorbable HYAFF, paroguide, poly DL-lactide and nonresorbable PTFE membranes were immersed in MEM containing 0.2 ng (125)I-TGFbeta(1) for different periods of time. It was found that HYAFF membrane and paroguide sequestered the most TGFbeta(1), which was then released in its active form (as shown by the CCL64 cell line bioassay). Untreated membranes and membranes enriched with TGFbeta(1) were then used as substrate for human bone cells to evaluate the synthesis of the osteoblast phenotype, as indicated by specific parameters. Results showed that membranes enriched with TGFbeta(1) increased alkaline phosphatase activity, collagen, and osteocalcin production more than untreated membranes. HYAFF and paroguide membranes, which sequestered the most of TGFbeta(1), were the most suitable for stimulating bone matrix proteins.

Silica, hyaluronate, and alveolar macrophage functional differentiation

BACKGROUND

Silicosis is mediated by macrophages, their soluble mediators, and extracellular matrix molecules. In this study, we investigated the effects of silica and/or hyaluronate (HA) on several alveolar macrophage responses.

METHODS

We evaluated glycosaminoglycan (GAG) production by radiolabeled precursors, nitric oxide (NO) release by its oxidation product, phagocytic activity by Candida albicans internalization, and the secretion of two fibrogenic cytokines, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta, by specific assays.

RESULTS

Silica significantly reduced GAG secretion, particularly HA secretion. Alone, it decreased Candida uptake; associated with HA, it enhanced the reduction. Silica and Candida reduced NO release, which was not significantly affected when silica- or Candida-exposed cells were also treated with HA. TNF-alpha and TGF-beta activities were stimulated by silica but reduced by HA.

CONCLUSIONS

The results suggest that silica and HA modify alveolar macrophage functional differentiation. Silica- and HA-induced modifications of the microenvironment could determine whether the response proceeds toward healing and repair or toward lung chronic pathology.

Silica, Hyaluronate, and Alveolar Macrophage Functional Differentiation

Background

Silicosis is mediated by macrophages, their soluble mediators, and extracellular matrix molecules. In this study, we investigated the effects of silica and/or hyaluronate (HA) on several alveolar macrophage responses.

Methods

We evaluated glycosaminoglycan (GAG) production by radiolabeled precursors, nitric oxide (NO) release by its oxidation product, phagocytic activity by Candida albicans internalization, and the secretion of two fibrogenic cytokines, tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β, by specific assays.

Results

Silica significantly reduced GAG secretion, particularly HA secretion. Alone, it decreased Candida uptake; associated with HA, it enhanced the reduction. Silica and Candida reduced NO release, which was not significantly affected when silica- or Candida-exposed cells were also treated with HA. TNF-α and TGF-β activities were stimulated by silica but reduced by HA.

Conclusions

The results suggest that silica and HA modify alveolar macrophage functional differentiation. Silica- and HA-induced modifications of the microenvironment could determine whether the response proceeds toward healing and repair or toward lung chronic pathology.

Expression profiles of craniosynostosis-derived fibroblasts

BACKGROUND

Craniosynostosis syndromes, a group of connective disorders characterized by abnormalities in vault osteogenesis and premature fusion of bone sutures, are associated with point mutations in FGF receptor family members. The cellular phenotype is characterized by abnormal extracellular matrix turnover.

MATERIAL AND METHODS

We used primary cultures of periosteal fibroblasts derived from two different craniosynostosis syndromes, the Apert and Crouzon syndromes. The FGFR2 third immunoglobulin-like domain and its flanking linker regions were analyzed for mutation. DNA microarrays containing 19,200 cDNAs were used to study the gene expression profiles of Apert and Crouzon fibroblasts. The pathologic cells were compared to wild-type human periosteal fibroblasts.

RESULTS

The P253R missense mutation and the G338R mutation were observed in Apert and Crouzon fibroblasts, respectively. The genetic profiles, as evaluated by DNA microarrays, yielded different clusters of expressed sequence tag (ESTs) expression within the experiment. Expression profiles from craniosynostosis-derived fibroblasts differ from those of wild-type fibroblasts (288 human ESTs, p< 0.01, pFDR = 0.12). Furthermore, two ESTs clusters discriminate the Crouzon from Apert fibroblasts. The differentially expressed genes cover a broad range of functional activities, including (1) bone differentiation, (2) cell-cycle regulation, (3) apoptotic stimulation, and (4) signaling transduction, cytoskeleton, and vesicular transport.

CONCLUSIONS

The transcriptional program of craniosynostosis fibroblasts differs from that of wild-type fibroblasts. Expression profiles of Crouzon and Apert fibroblasts can also be distinguished by two EST expression clusters, thus hinting at a different genetic background.

Crouzon's syndrome: differential in vitro secretion of bFGF, TGFbeta I isoforms and extracellular matrix macromolecules in patients with FGFR2 gene mutation

In the Crouzon's syndrome the cranial morphogenic processes are altered due to the early fusion of cranial sutures. We analysed the phenotype of cultured fibroblasts from normal subjects and from Crouzon patients with a specific fibroblast growth factor receptor 2 mutation resulting in a Cys 342 Tyr substitution within the third immunoglobulin domain. Crouzon fibroblasts differed from normal fibroblasts in their extracellular matrix macromolecule accumulation. In Crouzon fibroblasts glycosaminoglycans and fibronectin were decreased and type I collagen increased. As transforming growth factors beta (TGF beta) and basic fibroblasts growth factor (bFGF) together regulate extracellular matrix deposition, we evaluated TGF beta(1), TGF beta(3) and bFGF production by Crouzon and normal fibroblasts. TGF beta(1), TGFb(3) and bFGF levels were lower while TGF beta(1) mRNA transcripts were higher in Crouzon cells. As the increased TGF beta(1) gene expression did not translate into a parallel increase of secreted TGF beta(1), control of TGF beta(1) secretion may be mainly post-transcriptional. Furthermore, adding bFGF increased TGF beta(1) and TGF beta(3) secretion, suggesting the drop may be due to the altered signal transduction of bFGF. These innovative data suggest the in vitro differences between normal and Crouzon fibroblasts may be due to an imbalance in TGF beta and bFGF levels which alters the microenvironment where morphogenesis takes place.

Basic fibroblast growth factor autocrine loop controls human osteosarcoma phenotyping and differentiation

BACKGROUND

We focused on the phenotype of non-mineralizing MG 63 and mineralizing TE 85 human osteosarcoma cells and investigated the role of bFGF in modulating their differentiative responses. Basic FGF expression and bFGF effects on osteocalcin, runt-related transcription factor-2 (RUNX2), matrix molecular production and bFGF receptors, were evaluated.

MATERIALS AND METHODS

Osteocalcin and RUNX2 gene expression were studied by RT-PCR analysis. We evaluated cell proliferation by DNA content and performed differentiation studies on glycosaminoglican (GAG), collagen and proteoglican (PG) synthesis by using radiolabelled precursors and Northern blotting. BFGF receptors were quantified by bFGF receptor binding assay.

RESULTS

Osteocalcin is expressed in MG63 and TE65. RUNX2 RNA is differentially spliced in the two cell lines. BFGF elicits the effects of differentially splicing RUNX2. Proliferation, GAG synthesis, bFGF and proteoglycan mRNA expression, high and low affinity bFGF receptors, were more marked in MG 63 and differently affected by bFGF. Procollagen expression and alkaline phosphatase activity were significantly reduced. BFGF increased TE 85 cell proliferation and reduced TE 85 procollagen and osteocalcin production.

CONCLUSIONS

The different splice variants in RUNX2 gene in the two cell lines might be related to their different phenotypes. The less differentiated stage of MG63 could also be related to bFGF over-production and more bFGF receptors. The consequent increase in bFGF-bFGF receptor binding could explain the bFGF differentiative effects on MG 63. We suggest an autocrine role of bFGF endogenous release in controlling the different osteosarcoma phenotypes.

Basic fibroblast growth factor: effects on matrix remodeling, receptor expression, and transduction pathway in human periosteal fibroblasts with FGFR2 gene mutation

The Crouzon syndrome, which is associated with fibroblast growth factor receptor (FGFR2) mutations, is characterized by premature fusion of cranial sutures. We used an in vitro model of cultured periosteal fibroblasts from normal subjects and from Crouzon patients with FGFR2 mutation. We analyzed the matrix turnover rate and the effects of adding FGF2 by evaluating fibronectin synthesis and the activity of some proteolytic enzymes. To assess the role of some FGF signaling molecules involved in FGFR2 regulation, we studied Grb2 tyrosine phosphorylation and the phosphotyrosine proteins associated with Grb2. The iodinate FGF binding assay was performed to quantify FGFR expression. Compared with normal fibroblasts, fibronectin synthesis was decreased in Crouzon fibroblasts, and protease activities in cells and medium were enhanced, suggesting that excess fibronectin catabolism is present. Differences were more marked when FGF2 was added. Very few phosphoproteins were visible in anti-Grb2 immunoprecipitations from Crouzon fibroblasts, which showed a significant increase in the number of high-affinity and low-affinity FGF2 receptors. These results suggest that the abnormal genotype and the Crouzon cellular phenotype are related. To compensate the low levels of tyrosine phosphorylation, Crouzon cells might increase the numbers of FGFR2, thus increasing the cell surface binding sites for FGF2.

Effects of transforming growth factor-beta1 and tumour necrosis factor-alpha on cultured fibroblasts from skin fibroma as modulated by toremifene

To determine how toremifene, an anti-oestrogen triphenylethylene derivate, reduces tumour mass, we investigated its modulation of TGF-beta1 and TNF-alpha in fibroma fibroblasts. Normal and fibroma fibroblasts, isolated from patients affected by Gardner's syndrome without or with fibroma manifestation, were cultured in vitro. Secretion of GAG, collagen and TGF-beta1 was increased in fibroma fibroblasts compared to healthy cells. The increase in TGF-beta1 secretion into the medium was associated with a parallel increase in TGF-beta1 gene expression and receptor number. Receptor cross-linking studies using radiolabelled TGF-beta1 revealed more receptors, particularly types I and II, in fibroma fibroblasts than in normal cells. Normal and fibroma fibroblasts did not synthesise TNF-alpha, but they had TNF-alpha membrane receptors, as shown by TNF-alpha assay. TNF-alpha secreted by human monocytes, which may be present in the peritumoral area, increased cell proliferation and GAG accumulation and was, in turn, enhanced by TGF-beta1 treatment. Both growth factors increased angiogenesis, as shown by the CAM assay. Toremifene reduced TGF-beta1 secretion by fibroma fibroblasts and TNF-alpha secretion by monocytes, thus downregulating cell proliferation, ECM macromolecule accumulation and angiogenic progression. We hypothesise that increased TGF-beta1 gene expression and TGF-beta1 secretion in fibroma fibroblasts as well as the subsequent rise in TNF-alpha production by monocytes may facilitate fibroma growth and that toremifene inhibits autocrine and paracrine growth factor production.

Synthesis and secretion of transforming growth factor-beta1 by human desmoid fibroblast cell line and its modulation by toremifene

The present study provides evidence that the in vitro cultured fibroblast cell line from desmoid tumors differs from normal fibrobasts in its extracellular matrix (ECM) macromolecule composition and is modulated by treatment with toremifene, an antiestrogen that reduces tumor mass by an unknown mechanism. The results showed increased transforming growth factor-beta 1 (TGF-beta1) production, TGF-beta1 mRNA expression, and TGF-beta1 receptor number in desmoid fibroblasts compared with normal cells. As desmoid fibroblasts did not produce tumor necrosis factor-alpha (TNF-alpha) but were sensitive to it, which enhanced glycosaminoglycans (GAG) accumulation, we assessed the TGF-beta1 effects on TNF-alpha production by human monocytes. Our results showed TGF-beta1 significantly increased TNF-alpha secretion by monocytes. Toremifene mediated its effects in desmoid fibroblasts via an estrogen receptor-independent pathway. It inhibited GAG accumulation and the secretion of both latent and active forms of TGF-beta1 and had an inhibitory effect on TNF-alpha production by monocytes. Our results suggest that in reducing TGF-beta1 production by desmoid fibroblasts and TNF-alpha production by monocytes, toremifene may restore the balance between the two growth factors.

In vitro comparison of bioabsorbable and non-resorbable membranes in bone regeneration

BACKGROUND

Barrier membranes are used to prevent down-growth of the oral mucosa along the root surface and to allow alveolar bone regeneration in guided tissue regeneration. Several studies have demonstrated bone regenerates in the presence of bioabsorbable and non-resorbable membranes, but no studies have compared multiple bioabsorbable barriers to one another and to non-resorbable barriers. This study evaluated the in vitro influence of bioabsorbable and non-resorbable membranes on specific parameters of human osteoblast activity.

METHODS

Human osteoblasts were cultured on bioabsorbable membranes made of collagen, hyaluronic acid, and poly DL-lactide, and the most common non-resorbable membrane which is made of expanded polytetrafluoroethylene (ePTFE). The osteoblasts were cultured in vitro for 24 hours on barrier membranes in the presence of 3H-thymidine and 3H-proline to study cell proliferation and collagen synthesis. Transforming growth factor-beta1 (TGF-beta1) secretion was evaluated in conditioned media using an ELISA kit.

RESULTS

The results showed that collagen and poly DL-lactide stimulated DNA synthesis more than ePTFE and hyaluronic acid. All bioabsorbable membranes significantly increased collagen synthesis and alkaline phosphatase activity. Collagen and hyaluronic acid increased secretion of TGF-beta1, a growth factor involved in bone remodeling.

CONCLUSIONS

These data suggest bioabsorbable membranes, particularly collagen and hyaluronic acid, may promote bone regeneration through their activity on osteoblasts.

Bronchial epithelial cell matrix production in response to silica and basic fibroblast growth factor

BACKGROUND

Previous studies show that macrophages, lung fibroblasts, and their soluble mediators are responsible for the onset and development of pulmonary fibrosis. This study was conducted to determine whether airway epithelial cells are also directly involved in response to fibrogenic agents and consequently in the pathogenesis of lung fibrosis. To verify the hypothesis, we determined whether silica acts directly on human bronchial epithelial cells by stimulating cytokine and growth factor release and by modifying matrix production.

MATERIALS AND METHODS

An SV40 large T antigen-transformed human airway epithelial cell line, 16HBE14o (16HBE), was used. The expression profile of some proinflammatory interleukins (ILs), such as IL-1alpha, IL-1beta and IL-6 and their modulation by silica, were evaluated by polymerase chain reaction (PCR) analysis. Transforming growth factor beta (TGFbeta) and basic fibroblast growth factor (bFGF) mRNA levels were tested by Northern blotting in the presence and in the absence of silica. The silica- and/or bFGF-induced effects on matrix components (total proteins, collagen, and fibronectin) were also evaluated using radio-labeled precursors.

RESULTS

The results demonstrated 16HBE internalized silica particles. Silica induced a little IL-6 secretion, without affecting IL-1 and TGFbeta isoform production and strongly stimulated bFGF mRNA level and bFGF protein secretion. Silica also induced changes in 16HBE production of total proteins, collagen, and fibronectin production. When added in combination with the growth factor, it strengthened bFGF stimulation of matrix component secretion.

CONCLUSIONS

These results support the hypothesis that the changes in matrix components are due to a direct effect of silica on bronchial epithelial cells. Silica-induced over-secretion of bFGF suggests that autocrine and paracrine differentiation loops for bFGF may also be operative and that these mechanisms may be involved in the pathogenesis of pulmonary fibrosis. In the future, cytokine-directed therapeutic strategies might find a place in clinical practice.