Carbonic anhydrases III and IX are new players in the crosstalk between adrenocortical carcinoma and its altered adipose microenvironment.

PURPOSE: Adrenocortical carcinoma (ACC), a rare malignancy of the adrenocortex, is characterized by a crosstalk between the adipose microenvironment and tumor. Here, we assessed the involvement of carbonic anhydrase (CA) enzymes III and IX (CAIII and CAIX), in the metabolic alterations of the adipose tissue characterizing obesity and in the local crosstalk between the tumor adipose microenvironment and ACC. RESULTS/METHODS: CAIII and CAIX expression is altered in visceral adipose tissue (VAT) in obesity and in ACC. A significant CAIX upregulation was present in ACC at advanced stages (n = 14) (fold increase FI = 7.4 ± 0.1, P < 0.05) associated with lower CAIII levels (FI = 0.25 ± 0.06, P < 0.001), compared with lower stages (n = 9). In vitro coculture between visceral adipose stem cells (ASCs) and ACC cell lines, H295R and MUC-1, mimicking the interaction occurring between VAT and advanced ACC, showed a significant CAIX upregulation in H295R but not in MUC-1 cells, and a decreased expression of CAIII. The effect on adipose cells was different when cocultured with H295R or MUC-1 cells. Coculture did not modulate CAIII expression in ASCs, which, however, was significantly downregulated with H295R (FI = 0.34 ± 0.11, P < 0.05) and upregulated by MUC-1 when cocultured ASCs were induced to differentiate toward adipocytes, with an expression profile similar to what found in VAT of obese subjects. CAIX expression was markedly increased in ASCs cocultured with H295R and to a less extent following adipogenesis induction (FI = 150.9 ± 46.5 and FI = 4.6 ± 1.1, P < 0.01, respectively). CONCLUSION: Our findings highlight a modulation of CAIII and CAIX in the metabolic crosstalk between ACC and its local adipose microenvironment, suggesting that CAs might represent a potential target for novel anticancer therapies.

Management and outcome of metastatic pheochromocytomas/paragangliomas: a monocentric experience.

BACKGROUND: Pheochromocytoma (PHEO) and paraganglioma (PGL) are rare neuroendocrine tumors releasing catecholamines. Metastatic pheochromocytomas/paragangliomas (PPGLs) occur in about 5-26% of cases. To date, the management of patients affected by metastatic disease is a challenge in the absence of guidelines. AIM: The aim of this study was to evaluate the overall survival (OS) and the progression-free survival (PFS) in metastatic PPGLs. METHODS: Clinical data of 20 patients referred to the Careggi University Hospital (Florence, Italy) were retrospectively collected. Follow-up ranged from 1989 to 2019. Site and size of primary tumor, biochemical activity, genetic analysis and employed therapies were considered. Data were analyzed with SPSS version 27. RESULTS: Nine PHEOs (45%) and 11 PGLs (55%) were enrolled. Median age at diagnosis was 43.5 years [30-55]. Mean follow-up was 104.6 ± 89.3 months. Catecholamines were released in 70% of cases. An inherited disease was reported in 50% of patients. OS from the initial diagnosis (OSpt) and from the metastatic appearance (OSmtx) were lower in older patients (OSpt p = 0.028; OSmtx p < 0.001), abdominal PGLs (OSpt p = 0.007; OSmtx p = 0.041), larger tumors (OSpt p = 0.008; OSmtx p = 0.025) and sporadic disease (OSpt p = 0.013; OSmtx p = 0.008). CONCLUSION: Our data showed that older age at the initial diagnosis, sympathetic extra-adrenal localization, larger tumors and wild-type neoplasms are related to worse prognosis. Notably, the employed therapies do not seem to influence the survival of our patients. At present, effective treatments for metastatic PPGLs are missing and a multidisciplinary approach is indispensably required.

Human cell-based anti-inflammatory effects of rosiglitazone.

PURPOSE: The C-X-C motif chemokine ligand 10 (CXCL10) participates in diabetes and diabetic cardiomyopathy development from the early stages. Rosiglitazone (RGZ) exhibits anti-inflammatory properties and can target cardiomyocytes secreting CXCL10, under interferon (IFN)γ and tumor necrosis factor (TNF)α challenge. Cardiomyocyte remodeling, CD4 + T cells and dendritic cells (DCs) significantly contribute to the inflammatory milieu underlying and promoting disease development. We aimed to study the effect of RGZ onto inflammation-induced secretion of CXCL10, IFNγ, TNFα, interleukin (IL)-6 and IL-8 by human CD4 + T and DCs, and onto IFNγ/TNFα-dependent signaling in human cardiomyocytes associated with chemokine release. METHODS: Cells maintained within an inflammatory-like microenvironment were exposed to RGZ at near therapy dose (5 µM). ELISA quantified cytokine secretion; qPCR measured mRNA expression; Western blot analyzed protein expression and activation; immunofluorescent analysis detected intracellular IFNγ/TNFα-dependent trafficking. RESULTS: In human CD4 + T cells and DCs, RGZ inhibited CXCL10 release likely with a transcriptional mechanism, and reduced TNFα only in CD4 + T cells. In human cardiomyocytes, RGZ impaired IFNγ/TNFα signal transduction, blocking the phosphorylation/nuclear translocation of signal transducer and activator of transcription 1 (Stat1) and nuclear factor-kB (NF-kB), in association with a significant decrease in CXCL10 expression, IL-6 and IL-8 release. CONCLUSION: As the combination of Th1 biomarkers like CXCL10, IL-8, IL-6 with classical cardiovascular risk factors seems to improve the accuracy in predicting T2D and coronary events, future studies might be desirable to further investigate the anti-Th1 effect of RGZ.

The cytoskeleton actin binding protein filamin A impairs both IGF2 mitogenic effects and the efficacy of IGF1R inhibitors in adrenocortical cancer cells.

Adrenocortical carcinomas (ACCs) overexpress insulin-like growth factor 2 (IGF2), that drives a proliferative autocrine loop by binding to IGF1R and IR, but IGF1R/IR-targeted therapies failed in ACC patients. The cytoskeleton actin-binding protein filamin A (FLNA) impairs IR signalling in melanoma cells. Aims of this study were to test FLNA involvement in regulating IGF1R and IR responsiveness to both IGF2 and inhibitors in ACC. In ACC cells H295R and SW13 and primary cultures (1ACC, 4 adenomas) we found that IGF1R and IR interacted with FLNA, and FLNA silencing increased IGF1R and reduced IR expression, with a downstream effect of increased cell proliferation and ERK phosphorylation. In addition, FLNA knockdown potentiated antiproliferative effects of IGF1R/IR inhibitor Linsitinib and IGF1R inhibitor NVP-ADW742 in H295R. Finally, Western blot showed lower FLNA expression in ACCs (n = 10) than in ACAs (n = 10) and an inverse correlation of FLNA/IGF1R ratio with ERK phosphorylation in ACCs only. In conclusion, we demonstrated that low FLNA levels enhance both IGF2 proliferative effects and IGF1R/IR inhibitors efficacy in ACC cells, suggesting FLNA as a new factor influencing tumor clinical behavior and the response to the therapy with IGF1R/IR-targeted drugs.

The IGF2 methylation score for adrenocortical cancer: an ENSAT validation study.

Adrenocortical carcinoma (ACC) is diagnosed using the histopathological Weiss score (WS), but remains clinically elusive unless it has metastasized or grows locally invasive. Previously, we proposed the objective IGF2 methylation score as diagnostic tool for ACC. This multicenter European cohort study validates these findings. Patient and tumor characteristics were obtained from adrenocortical tumor patients. DNA was isolated from frozen specimens, where after DMR2, CTCF3, and H19 were pyrosequenced. The predictive value of the methylation score for malignancy, defined by the WS or metastasis development, was assessed using receiver operating characteristic curves and logistic and Cox regression analyses. Seventy-six ACC patients and 118 patients with adrenocortical adenomas were included from seven centers. The methylation score and tumor size were independently associated with the pathological ACC diagnosis (OR 3.756 95% CI 2.224-6.343; OR 1.467 95% CI 1.202-1.792, respectively; Hosmer-Lemeshow test P = 0.903), with an area under the curve (AUC) of 0.957 (95% CI 0.930-0.984). The methylation score alone resulted in an AUC of 0.910 (95% CI 0.866-0.952). Cox regression analysis revealed that the methylation score, WS and tumor size predicted development of metastases in univariate analysis. In multivariate analysis, only the WS predicted development of metastasis (OR 1.682 95% CI 1.285-2.202; P < 0.001). In conclusion, we validated the high diagnostic accuracy of the IGF2 methylation score for diagnosing ACC in a multicenter European cohort study. Considering the known limitations of the WS, the objective IGF2 methylation score could potentially provide extra guidance on decisions on postoperative strategies in adrenocortical tumor patients.

A unique neuroendocrine cell model derived from the human foetal neural crest.

PURPOSE: Nowadays, no human neuroendocrine cell models derived from the neural crest are available. In this study, we present non-transformed long-term primary Neural Crest Cells (NCCs) isolated from the trunk region of the neural crest at VIII-XII gestational weeks of human foetuses obtained from voluntary legal abortion. METHODS AND RESULTS: In NCC, quantitative real-time RT PCR demonstrated the expression of neural crest specifier genes, such as Snail1, Snail2/SLUG, Sox10, FoxD3, c-Myc, and p75NTR. Moreover, these cell populations expressed stemness markers (such as Nanog and nestin), as well as markers of motility and invasion (TAGLN, MMP9, CXCR4, and CXCR7), and of neuronal/glial differentiation (MAP2, GFAP, SYP, and TAU). Functional analysis demonstrated that these cells not only possessed high migration properties, but most importantly, they expressed markers of sympatho-adrenal lineage, such as ASCL1 and tyrosine hydroxylase (TH). Moreover, the expression of TH increased after the induction with two different protocols of differentiation towards neuronal and sympatho-adrenal phenotypes. Finally, exposure to conditioned culture media from NCC induced a mature phenotype in a neuronal cell model (namely SH-SY5Y), suggesting that NCC may also act like Schwann precursors. CONCLUSION: This unique human cell model provides a solid tool for future studies addressing the bases of human neural crest-derived neuroendocrine tumours.

Can the positive association of osteocalcin with testosterone be unmasked when the preeminent hypothalamic-pituitary regulation of testosterone production is impaired? The model of spinal cord injury.

PURPOSE: Osteocalcin (OCN), released from the bone matrix during the resorption phase, in its undercarboxylated form, stimulates testosterone (T) biosynthesis in mouse and a loss-of-function mutation of its receptor was associated with hypergonadotropic hypogonadism in humans. Nevertheless, when population-based studies have explored the OCN-T association, conflicting results have been reported. Hypothesizing that the evidence of a positive association between OCN and T could have been hindered by the preeminent role of a well-functioning hypothalamus-pituitary axis in promoting T biosynthesis, we explored this association in men with chronic spinal cord injury (SCI), exhibiting high prevalence of non-hypergonadotropic androgen deficiency. METHODS: Fifty-five consecutive men with chronic SCI underwent clinical/biochemical evaluations, including measurements of total T (TT), OCN and 25(OH)D levels. Free T (FT) levels were calculated by the Vermeulen formula. Comorbidity was scored by Charlson comorbidity index (CCI). RESULTS: A biochemical androgen deficiency (TT < 300 ng/dL) was observed in 15 patients (27.3%). TT was positively correlated with OCN, 25(OH)D and leisure time physical activity and negatively correlated with age, BMI and CCI. OCN was also positively correlated with calculated FT and negatively correlated with BMI and HOMA-IR. At the multiple linear regression analyses, a positive association of OCN with TT and calculated FT persisted after adjustment for confounders. CONCLUSIONS: The positive association here found between OCN and T levels in men with chronic SCI reinforces the notion that a bone-testis axis is also functioning in humans and suggests that it can be unmasked when the preeminent hypothalamic-pituitary regulation of T production is impaired.

Adrenocortical carcinoma: the dawn of a new era of genomic and molecular biology analysis.

Over the last decade, the development of novel and high penetrance genomic approaches to analyze biological samples has provided very new insights in the comprehension of the molecular biology and genetics of tumors. The use of these techniques, consisting of exome sequencing, transcriptome, miRNome, chromosome alteration, genome, and epigenome analysis, has also been successfully applied to adrenocortical carcinoma (ACC). In fact, the analysis of large cohorts of patients allowed the stratification of ACC with different patterns of molecular alterations, associated with different outcomes, thus providing a novel molecular classification of the malignancy to be associated with the classical pathological analysis. Improving our knowledge about ACC molecular features will result not only in a better diagnostic and prognostic accuracy, but also in the identification of more specific therapeutic targets for the development of more effective pharmacological anti-cancer approaches. In particular, the specific molecular alteration profiles identified in ACC may represent targetable events by the use of already developed or newly designed drugs enabling a better and more efficacious management of the ACC patient in the context of new frontiers of personalized precision medicine.

Which is the main molecular target responsible for the cardiovascular benefits in the EMPA-REG OUTCOME trial? A journey through the kidney, the heart and other interesting places.

BACKGROUND: The results of the EMPA-REG-OUTCOME trial on type 2 diabetic patients at high risk for prior cardiovascular events showed that empagliflozin produces a remarkable reduction in the rates of hospitalization for heart failure (35%), cardiovascular death (38%), and all-cause death (32%). This unexpected cardio-protective action cannot be accounted for by the improvement of "classical" cardiovascular risk factors. AIMS: This review aims at summarizing current knowledge on the cardiovascular action of SGLT2 inhibitors and discuss the different hypotheses formulated to explain the results of the EMPA-REG-OUTCOME-study. DATA SYNTHESIS: We discuss in detail the major cardiovascular outcomes of the study in the light of the potential systemic and myocardial mechanisms of action of the drug. In addition, we propose and speculate on a direct effect of empagliflozin on cardiomyocytes. CONCLUSIONS: The available evidence is insufficient to establish any of the proposed mechanisms of cardiovascular action of empagliflozin. While awaiting for the results of ongoing clinical studies with other SGLT2 inhibitors, the most promising putative mechanisms still deserve to be confirmed with specifically designed, yet unavailable, pre-clinical studies.

Osteocalcin increase after bariatric surgery predicts androgen recovery in hypogonadal obese males.

OBJECTIVE: Bone modulates testis function through osteocalcin (OCN) production. This paper assesses the association between serum OCN and androgen production recovery in morbidly obese males at 9 months after bariatric surgery. SUBJECTS: A cohort of n=103 obese males with mean±s.d. body mass index (BMI) 47.7±8.2 kg m(-2), age 42±11 years, consisting of n=76 patients undergoing gastric bypass and n=27 in the waiting list for surgery. RESULTS: At 9 months from surgery, a significant increase was observed in mean±s.d. total OCN (tOCN=10.4±10.3 ng ml(-1), P<0.001) and undercarboxylated OCN (ucOCN=5.4±3.7 ng ml(-1), P<0.001), total testosterone (TT, 5.6±6.5 nM, P<0.001) and calculated free testosterone (cFT, 0.035±0.133 nM, P<0.006), sex hormone binding globulin (SHBG, 21.2±16.7 nM, P<0.001) and decrease in estradiol (E2, -30.1±51.9 pM, P<0.001) levels only in operated patients, with a significant reduction in BMI (24%) and waist (20%). A positive correlation existed between tOCN and ucOCN (age-adjustment (age-adj.): ß=0.692, P<0.001) and their variations (age-adj.: ß=0.629, P<0.001) after surgery. Multivariate analysis in operated patients showed a significant positive association between variations in tOCN and TT (age-adj.: ß=0.289, P=0.012), SHBG (age-adj.: ß=0.326, P=0.005) but not with cFT variation. tOCN, but not luteinizing hormone (LH) variation was the only significant predictive factor of cFT recovery in the hypogonadal (TT<12 nM) operated subjects even after age- and BMI-adjustment (adj.: ß=0.582, P<0.05). cFT improvement was significantly higher when considering operated patients with tOCN increase (0.045±0.123 vs -0.02±0.118 nM, P=0.015), hypogonadism (0.059±0.111 vs -0.059±0.138 nM, P=0.002) and younger than 35 years (0.102±0.108 vs -0.019±0.123 nM, P=0.009). CONCLUSION: OCN recovery observed after bariatric surgery is significantly associated with cFT improvement independently of BMI variation and age in hypogonadal morbidly obese males.

Elocalcitol inhibits inflammatory responses in human thyroid cells and T cells.

T-helper 1 (Th1) cell-mediated inflammatory responses predominate in the early pathogenesis of Graves' disease (GD), whereas Th2 cell-mediated immunity may play a role in later stages. The chemokine CXCL10 and its receptor CXCR3 are expressed in most thyroid glands of early GD patients. Circulating CXCL10 levels inversely correlate with disease duration; CXCL10 maximal expression also correlates with interferon (IFN)gamma levels in recent GD onset. Methimazole (MMI) reduces CXCL10 secretion by isolated thyrocytes, decreases serum CXCL10 levels, and promotes a transition from Th1 to Th2 dominance in patients in GD active phase. Vitamin D receptor agonists exhibit antiinflammatory properties and promote tolerance induction. We investigated the effects and the mechanism of action of a nonhypercalcemic vitamin D receptor agonist, elocalcitol (BXL-628), compared with MMI on CXCL10 secretion induced by proinflammatory cytokines. Furthermore, we studied the effects of both drugs on Th1, Th17, and Th2 cytokine secretion in CD4+ T cells. ELISA, cytometry, immunocytochemistry, Western blot, and quantitative real-time PCR were used for protein and gene analysis. In human thyrocytes, elocalcitol inhibited IFNgamma and TNFalpha-induced CXCL10 protein secretion more potently than MMI. Elocalcitol impaired both cytokine intracellular pathways, whereas MMI was effective only on the IFNgamma pathway. In CD4+ T cells, elocalcitol decreased Th1- and Th17-type cytokines, and promoted Th2-type cytokine secretion. Elocalcitol and MMI inhibited Th1 cytokine-mediated responses in thyrocytes and CD4+ T cells. In addition, elocalcitol promoted a shift toward a Th2 response. In conclusion, elocalcitol could represent a novel pharmacological tool in the treatment of autoimmune thyroid diseases.

The Y606C RET mutation causes a receptor gain of function.

CONTEXT: Medullary thyroid carcinoma (MTC) is the most common feature of multiple endocrine neoplasia type 2A (MEN2A) and occurs in almost all patients affected by germline RET mutations. OBJECTIVE: We identified and characterized an activating germline RET point mutation (G>A substitution leading to the heterozygous missense mutation Y606C in exon 10), in a 58-year-old female affected by MTC. DESIGN: The RET/Y606C and RET/C620Y, obtained by site-directed mutagenesis, as well as the RET/wild-type (wt) were cloned in an expression vector and transiently transfected in NIH3T3 fibroblasts. In vitro cell model was used to evaluate the effect of Y606C mutation on the RET downstream signalling pathways through Western blot analysis. RESULTS: We found that the cysteine insertion, due to the Y606C mutation, results in increased receptor dimerization, which is accompanied by an increased tyrosine phosphorylation of the Y905 residue in the RET/Y606C, demonstrating that the Y606C mutation is associated with constitutive receptor activation. As RET activation results in an intracellular signalling cascade involving extracellular signal-regulated kinases (ERKs), we investigated ERK activity in our transfected cells. Results demonstrated a significant increase in ERK2 phosphorylation in the RET/Y606C vs. the RET/wt and RET/C620Y transfected cells, suggesting an up-regulation of RET signalling. CONCLUSIONS: All these findings demonstrate that the Y606C mutation is associated with RET constitutive activation and thus has to be considered of pathogenetic relevance in the development of MTC.

Peripheral regulatory mechanisms in erection.

The most important pathway underlying the penile erection is the nonadrenergic/noncholinergic signalling, which through the release of nitric oxide (NO), leads to an intracellular increase of cyclic GMP (cGMP), the main secondary messenger mediating tumescence in the penis. Interestingly, both cGMP formation and degradation are affected by testosterone (T). In fact, beyond the well-known role of T in regulating sexual desire and NO release, recent experimental evidences from our group showed that T also regulates the expression of phosphodiesterase type 5 (PDE5), the hydrolytic enzyme involved in cGMP breakdown. This antithetic role of T seems to be the main way through which the peripheral hormonal regulation of penile erections occurs, allowing an important synchronization between erectile processes and sexual desire. Hence, erections are still possible in hypogonadal conditions where a decreased cGMP formation, because of impaired NO production, is counterbalanced by a reduced cGMP hydrolysis. The purpose of this review is to describe evidences about the peripheral role of T in regulating penile erection and to justify the importance to test T plasma levels in those patients with erectile dysfunction who do not respond to PDE5 inhibitors.

Identification, localization and functional in vitro and in vivo activity of oxytocin receptor in the rat penis.

We recently found that the oxytocin receptor (OTR) is expressed in the human and rabbit corpus cavernosum and mediates contractility in vitro. The present study extended our investigations to the rat, and explored whether OTR regulates penile detumescence in vivo. Real-time RT-PCR quantitatively characterized the distribution of OTR mRNA in the male genital tract. Specific transcripts for OTR were expressed in all the tissues investigated. Penile expression of OTR was comparable to that observed in testis and prostate. Western blot analysis detected a single band of the expected molecular mass for OTR in all tissues examined, including rat penis. Expression of OTR protein in rat penile extracts was further confirmed by binding studies, using the OTR selective radiolabeled ligand 125I-OTA (K(d) = 17 +/- 6.5 pM, B(max)=15.7 +/- 5 fmoles/mg protein). OTR was immunolocalized to the endothelial and smooth muscle compartments of cavernous spaces and blood vessels. In rat corpus cavernosum strips, oxytocin (OT) and an OTR selective agonist ([Thr4,Gly7]OT) induced identical increases in tension, while different vasopressin agonists were less active. In vivo, OT intra-cavernous injection (ICI) dose-dependently inhibited intracavernous pressure (ICP) increase elicited by either electrical stimulation of the cavernous nerve or ICI of papaverine with similar IC(50)s (117.7 +/- 37 mU). The OTR antagonist, atosiban, counteracted the contractile effect of OT both in vitro and in vivo. Atosiban alone significantly increased ICP at lower stimulation frequencies (2 Hz = P<0.001 and 4 Hz = P<0.05 vs control), but not at the maximal frequency (16 Hz). Our data showed that OTR is present in the rat penis and mediates contractility both in vitro and in vivo, therefore suggesting a role for OT in maintaining penile detumescence.

Tyrosine phosphorylation of the a kinase anchoring protein 3 (AKAP3) and soluble adenylate cyclase are involved in the increase of human sperm motility by bicarbonate.

Mammalian testicular spermatozoa are immotile, thus, to reach the oocyte, they need to acquire swimming ability under the control of different factors acting during the sperm transit through the epididymis and the female genital tract. Although bicarbonate is known to physiologically increase motility by stimulating soluble adenylate cyclase (sAC) activity of mammalian spermatozoa, no extensive studies in human sperm have been performed yet to elucidate the additional molecular mechanisms involved. In this light, we investigated the effect of in vitro addition of bicarbonate to human spermatozoa on the main intracellular signaling pathways involved in regulation of motility, namely, intracellular cAMP production and protein tyrosine phosphorylation. Bicarbonate effects were compared with those of the phosphatidyl-inositol-3 kinase inhibitor, LY294002, previously demonstrated to be a pharmacological stimulus for sperm motility. Bicarbonate addition to spermatozoa results in a significant increase in sperm motility as well as in several hyperactivation parameters. This stimulatory effect of bicarbonate and LY294002 is mediated by an increase in cAMP production and tyrosine phosphorylation of the A kinase anchoring protein, AKAP3. The specificity of bicarbonate effects was confirmed by inhibition with 4,4'-di-isothiocyanostilbene-2,2'-disulfonic acid. We remark that, in human spermatozoa, bicarbonate acts primarily through activation of sAC to stimulate tyrosine phosphorylation of AKAP3 and sperm motility because both effects are blunted by the sAC inhibitor 2OH-estradiol. In conclusion, our data provide the first evidence that bicarbonate stimulates human sperm motility and hyperactivation through activation of sAC and tyrosine phosphorylation of AKAP3, finally leading to an increased recruitment of PKA to AKAP3.

Human spermatozoa as a model for studying membrane receptors mediating rapid nongenomic effects of progesterone and estrogens.

In the past few years, besides the classical genomic effects of steroid hormones, a plethora of so called rapid non genomic effects have been described in different cell types, which are too rapid to be due to activation of gene expression. Although some of these effects might involve the same nuclear steroid receptors acting on different cellular signalling, others have been ascribed to poorly characterized membrane receptors. Several rapid nongenomic effects of progesterone (P) and estrogens (E) have been recently demonstrated in human spermatozoa. They seem to be mediated by the steroid binding to specific receptors on plasma membrane different from the classical ones. In particular, P has been demonstrated to stimulate calcium influx, tyrosine phosphorylation of sperm proteins, including extracellular signaling regulated kinases, chloride efflux and cAMP increase, finally resulting in activation of spermatozoa through induction of capacitation, hyperactivated motility and acrosome reaction. Conversely, E, by acting rapidly on calcium influx and on protein tyrosine phosphorylation, seem to modulate sperm responsiveness to P. Several attempts have been used to characterize the putative membrane receptors for P (mPR) and E (mER) in spermatozoa, however their isolation still remains elusive. However, in the past few years our laboratory has obtained several evidences supporting the existence and functional activity of mPR and mER in human spermatozoa. To characterize these membrane receptors, we used two antibodies directed against the ligand binding domains of the classical receptors, namely c262 and H222 antibodies for PR and ER respectively, hypothesizing that these regions should be conserved between nongenomic and genomic receptors. In western blot analysis of sperm lysates the antibodies detected a band of about 57 kDa for PR and of 29 kDa for ER, excluding the presence of the classical receptors. On live human spermatozoa, both antibodies were able to block the calcium and AR response to P and E respectively, whereas, antibodies directed against different domains of the classical PR and ER were ineffective. Moreover, c262 antibody also blocks in vitro human sperm penetration of hamster oocytes. Taken together all these data strongly support the existence of mPR and mER different from the classical ones, mediating rapid effects of these steroid hormones in human spermatozoa.

Phosphatidylinositol 3-kinase inhibition enhances human sperm motility and sperm-zona pellucida binding.

Various signalling pathways are involved in the regulation of sperm motility, capacitation, acrosome reaction and sperm-zona binding. Recent data pointed out an important role for phosphatidylinositol 3-kinase (PI3K) in human sperm motility. However, no study as of yet has been carried out to determine the effect of sperm treatment with the PI3K inhibitor LY294002 on other sperm parameters. In the present study, we investigated the role of PI3K on human sperm motility, acrosome reaction and sperm-oocyte binding by using this inhibitor. We demonstrate that in vitro incubation of washed unselected spermatozoa with LY294002 increased the percentage motility and progressive motility in asthenozoospermia patients as evaluated by computer-aided sperm analysis. The compound furthermore did not influence the acrosome reaction, whilst it (further) slightly enhanced sperm-oocyte binding. Our results therefore imply that PI3K negatively affects sperm motility and oocyte binding and might suggest a possible therapeutic role for PI3K inhibitors in the treatment regime for asthenozoospermia.

Effects of hypoxia on endothelin-1 sensitivity in the corpus cavernosum.

The penis remains in a hypo-oxygenated, flaccid state for a large majority of the time. In this study, we investigated the effect of changing oxygen tension on the expression and functional activity of endothelin-1 (ET-1) receptors in the penis. Experiments were performed in rabbit and human corpora cavernosa (CC) as well as in human fetal penile tissue and cell cultures [human fetal penile endothelial cells (hfPECs) and human fetal smooth muscle cells (hfPSMCs)]. Endothelin A (ETA) receptors are expressed by both endothelial and muscular cells in all tissues investigated. Only penile endothelial cells express endothelin B (ETB) receptors, which are further turned on during experimental hypoxia. In addition, hypoxia also allows ETB expression in the muscular compartment without affecting ETA expression. This hypoxia-induced over-expression of ETB decreased the contractile activity of ET-1 and increased ETB-mediated relaxation. The latter was essentially related to increased ETB-mediated nitric oxide formation in hfPEC and even in hfPSMC. Hypoxia also induced a time-dependent down-regulation of RhoA and Rho kinase (ROK) expression which, in turn, participated in the decreased contractile activity of ET-1 in the hypoxic penile tissue. Accordingly, during hypoxia, an ROK inhibitor, Y27632, was less effective in relaxing ET-1-precontracted strips. In conclusion, prolonged (24 h) hypoxia stimulated several counter-regulatory mechanisms in penile tissue, including up-regulation of ETB and down-regulation of RhoA/ROK pathways, which may help to preserve CC hypo-oxygenation, allowing smooth muscle relaxation and, most probably, penile erection.

How do sperm swim? Molecular mechanisms underlying sperm motility.

Motility is a characteristic function of the male gamete, which allows spermatozoa to actively reach and penetrate the female gamete in organisms with internal and external fertilization. Sperm motility is acquired under the control of many extrinsic and intrinsic factors and is based on the specialized structure of the sperm flagellum. After a brief overview of how the sperm flagellum is organized and works to support cell motility, the present review focuses on the molecular mechanisms and factors involved in the development and maintenance of sperm motility. Data obtained both in organisms with external fertilization, such as fishes and sea urchin, and with internal fertilization, such as Mammals, are critically analyzed. In particular, a great attention has been put on the ionic mechanisms and on the involvement of protein kinases and phosphatases in regulation of sperm motility. A brief overview of the pharmacological and physiological molecules which have been studied for their possible application as therapeutic molecules for in vitro treatment of defects of sperm motility in asthenozoospermic human subjects, is presented. Moreover, we show some preliminary data obtained in our laboratory on the involvement of the phosphatydilinositol 3-kinase and the A kinase anchoring protein (AKAP3) in regulation of motility in human spermatozoa. The last section is dedicated to hyperactivation, a peculiar pattern of motility which is developed in association with capacitation occurring during sperm transit through the female genital tract and which can also be obtained in vitro by incubation in defined media.