Biomedical subjects

Rita Canipari

Publications and source records attributed to Rita Canipari.

7 recordsLinked to original sources

PubMed2006

Urokinase plasminogen activator and TGF-beta production in immunosuppressed patients with and without P. Jiroveci infection.

Macrophages play a pivotal role in a host's defence against pulmonary infections. Macrophage functions are impaired in immunosuppressed (IS) patients, regardless of whether they are HIV-positive (HIV+) or -negative (HIV-). Several studies have indicated that urokinase plasminogen activator (uPA) and transforming growth factor beta (TGF-beta) are important factors in a host's defence against pulmonary pathogens. We measured uPA and TGF-beta activity in unstimulated peripheral blood monocytes (PBM) of both HIV-infected and non-infected IS patients with or without Pneumocystis jiroveci (formerly carinii) pneumonia (PCP). As previously found in alveolar macrophages (AMs), the majority of uPA activity was found in cell lysates. The highest values of uPA activity were found in control subjects. All the patients displayed a decreased production of uPA, irrespective of HIV infection. Similarly, active TGF-beta was higher in control subjects than in HIV+ and IS patients. The presence of P. jiroveci infection further lowered uPA and TGF-beta activity. Decreased TGF-beta activation might be a consequence of lower uPA production, which may, in turn, influence virus replication, since it has been demonstrated that TGF-beta can suppress human HIV expression in monocytes/macrophages. Further studies are warranted to elucidate whether the decrease in uPA and TGF-beta activity impairs a host's defence against P. jiroveci infection.

Adult↗

PubMed2006

Characterization and expression of different pituitary adenylate cyclase-activating polypeptide/vasoactive intestinal polypeptide receptors in rat ovarian follicles.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a bioactive peptide transiently expressed in preovulatory follicles. PACAP acts by interacting with three types of PACAP receptors. PACAP type I receptor (PAC(1)-R), which binds specifically to both PACAPs and vasoactive intestinal polypeptide (VIP), although with lower affinity, and two VIP receptors, VPAC(1)-R and VPAC(2)-R, which bind to PACAP and VIP with equal affinity. In the present study, we showed the expression of all three receptors in whole ovaries obtained from juvenile and gonadotropin-treated immature rats. A more detailed analysis on cells from preovulatory follicles showed that PAC(1)-R and VPAC(2)-R were expressed in granulosa cells, whereas only VIP receptors were expressed in theca/interstitial (TI) cells and fully grown oocytes presented only PAC(1)-R. The distribution of the VIP receptors was confirmed by immunofluorescence. HCG treatment induced stimulation of PAC(1)-R in granulosa cells and VPAC(2)-R in TI cells. The presence of functional PACAP/VIP receptors was also supported by metabolic studies. We further evaluated the presence of PACAP and VIP receptors by testing the effect of these peptides on apoptosis in granulosa cells cultured, isolated or in whole follicles. Treatment of follicles with PACAP and VIP dose-dependently inhibited apoptosis, while only PACAP significantly inhibited isolated granulosa cells. These results demonstrate a different expression of PACAP/VIP receptors in the various follicle compartments and suggest a possible role for PACAP and VIP on granulosa and TI cells, both during follicle development and ovulation.

Animals↗

PubMed2004

Effects of insulin-like growth factor I and II on prostaglandin synthesis and plasminogen activator activity in human umbilical vein endothelial cells.

IGFs seem to contribute to the endothelial dysfunction observed in some vascular diseases. Because locally increased IGFs levels were detected in the preeclamptic fetoplacental unit, we hypothesized their involvement in the dysregulation of fibrinolysis and vascular tone typically observed in the fetoplacental compartment in this pregnancy disease. Therefore, in human umbilical vein endothelial cells (HUVECs), the potential effect of IGFs on the synthesis of plasminogen activators (PAs), PA inibitor-1 (PAI-1), and vasodilator and vasoconstrictor prostaglandins (PGs) was investigated. Moreover, in HUVECs treated with IGFs, the expression of cyclooxygenase (COX)-2, the rate-limiting enzyme in PG synthesis, was evaluated.HUVECs were treated for 24 h with IGFs (1-100 ng/ml) or IL-1beta (0.1 ng/ml). PA, PAI-1, and COX-2 mRNA was determined by RT-PCR and PG release and PA activity by RIA and colorimetric assay, respectively.We demonstrated an inhibition of urokinase-type PA activity and a 50% reduction of urokinase-type PA mRNA in HUVECs treated with IGFs. No effect was seen on PAI-1. Finally, both IGFs significantly decreased all PGs tested and COX-2 mRNA, whereas, as expected, IL-1beta had an opposite effect. In conclusion, our results suggest for IGFs a potential involvement in the endothelial dysfunction observed in preeclamptic fetoplacental unit.

Cells, Cultured↗

PubMed2004

Granulosa cell-oocyte interactions.

Throughout oogenesis the oocyte and follicle cells establish an intricate system of mutual interactions that ultimately lead to the acquisition of their respective competences. Paracrine factors released by both cell types are believed to stimulate formation of the primordial follicle and support the initial phases of follicle growth. At the same time, these processes are also dependent on gap junction communication between the germinal and somatic compartment. At later stages of follicle development, activities released by the oocyte induce the adjacent granulosa cells to express a specialized phenotype. In their turn, these cells crucially regulate the ability of the oocyte to progress through the meiotic process and acquire full developmental potential.

Cell Communication↗

PubMed2004

Influence of thyroid hormone on mouse preantral follicle development in vitro.

OBJECTIVE: To evaluate the role of 3,3',5-triiodothyronine (T(3)) on ovarian follicle development in vitro. DESIGN: Experimental study. SETTING: University reproductive biology unit. ANIMAL(S): CD1 mice (female). INTERVENTION(S): In vitro culture. MAIN OUTCOME MEASURE(S): Assessment of follicle and oocyte development following a 6-day culture with FSH (100 mU/mL), (Bu)(2)cAMP (0.5 mM), and T(3) (1-100 nM), alone or in combination. RESULT(S): A high percentage of in vitro grown (IVG) FSH-stimulated follicles formed an antral cavity (AC), while the addition of T(3) (100 nM) significantly reduced this response in a statistically significant manner. A statistically significant recovery of AC formation was obtained by limiting exposure to 4 days of culture. Formation of AC was induced by (Bu)(2)cAMP, which prevented T(3)-mediated suppression of AC formation. Under different conditions, high proportions of germinal vesicle-arrested IVG oocytes displayed condensed chromatin configuration. The capacity to undergo germinal vesicle breakdown (GVBD) was similar in all groups, and a statistically significant reduction in the percentage of oocytes with PB1 was recorded when T(3) was added to FSH or (Bu)(2)cAMP. This ability was partially recovered by removing T(3) on day 4 of culture. CONCLUSION(S): Exposure to high T(3) concentrations can impair preantral follicle development, but this effect can be partly reverted by restoring a physiological hormonal milieu before follicle commitment to antral development.

Animals↗

PubMed2003

Effect of pituitary adenylate cyclase-activating polypeptide and vasoactive intestinal polypeptide on mouse preantral follicle development in vitro.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a bioactive peptide isolated from ovine hypothalamus. It is transiently expressed in preovulatory follicles and positively affects several parameters correlated with the ovulatory process. It has also been shown to be expressed in the interstitial tissue around primordial and preantral follicles. The aim of the present study was to investigate whether PACAP influences preantral follicle growth and differentiation. Mouse preantral follicles were cultured for 5 d in the presence of FSH and increasing concentrations of PACAP or vasoactive intestinal polypeptide (VIP) (10(-12) to 10(-7) m). In the presence of FSH, follicles increased in diameter and formed an antrum. At the concentrations tested, neither PACAP alone nor VIP alone had any effect on follicle development, but the addition of either peptide to FSH-stimulated follicles caused a dose-dependent inhibition of follicle growth, antrum formation, granulosa cell proliferation, and estradiol production. The effect of PACAP on follicle growth and antrum formation was directly correlated with the length of stimulation and was reversible. Although exposure of follicles to 10(-7) m PACAP and VIP did not affect oocyte growth, it severely impaired completion of meiotic maturation in oocytes isolated from the follicles and cultured for 17 h in medium alone. The cyclic production of PACAP by preovulatory follicles during the estrous cycle in adult rats and its induction by LH in the rat and mouse ovary suggest that this peptide may play a role in the local regulation of preantral follicle growth.

Animals↗

PubMed2002

Pituitary adenylate cyclase-activating polypeptide modulates plasminogen activator expression in rat granulosa cell.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a bioactive peptide isolated from ovine hypothalamus. It has been demonstrated to be transiently expressed in preovulatory follicles and to positively affect several parameters correlated with the ovulatory process. The aim of the present study was to investigate whether PACAP influences the plasminogen/plasmin system in rat ovary. Plasminogen activators (PAs) are serine proteases, modulated by gonadotropins and several peptides in preovulatory follicles, that appear to be involved in ovulation. Granulosa cells obtained from immature eCG-treated rats were cultured for 24 h in the presence of increasing concentrations of PACAP and vasoactive intestinal peptide (VIP). A significant, dose-dependent increase in tissue-type PA (tPA) activity and decrease in urokinase-type (uPA) PA activity were observed in PACAP-treated cells. These effects were exerted at the mRNA level. The use of cycloheximide, a protein synthesis inhibitor, suggested that PACAP requires an intermediary protein to decrease uPA-mRNA, but not to induce tPA-mRNA. However, no significant modulation of PAs was observed in the presence of VIP. When granulosa cells were stimulated within the intact follicle (i.e., maintaining the three-dimensional structure and in the presence of the theca cell layers), both PACAP and VIP dose-dependently stimulated tPA. These data suggest that, in addition to the PACAP type I receptor present on granulosa cells, different subtypes of PACAP receptors are present in the different ovarian compartments.

Animals↗