Ruthenium(II) Polypyridyl Complexes with Benzoxazole Derivatives and Non-Innocent Ligands as Effective Antioxidants in Human Neuroblasts.

Ruthenium(II) polypyridyl complexes continue to raise increasing interest for the encouraging results in several biomedical areas. Considering their vast chemical-physical repertoire, in particular the possibility to switch from the sensitization of reactive oxygen species (ROS) to ROS-scavenging abilities by tuning the nature of their ligands, it is therefore surprising that their potential as antioxidants has not been largely investigated so far. Herein, we explored the antioxidant behaviour of the novel ruthenium compound [Ru(dbpy)(2,3-DAN)Cl]PF6 (Ru1), featuring a benzoxazole derivative (dpby=2,6-bis(4-methyl-2-benzoxazolyl)pyridine) and the non-innocent 2,3-diamminonaftalene (2,3-DAN) ligand, along with the reference tpy-containing analogue [Ru(tpy)(2,3-DAN)Cl]PF6 (Ru2) (tpy=2,2':6',2''-terpyridine). Following the synthesis and the electrochemical characterization, chemical antioxidant assays highlighted the beneficial role of dpby for the ROS-scavenging properties of Ru1. These data have been corroborated by the highest protective effect of Ru1 against the oxidative stress induced in SH-SY5Y human neuroblastoma, which exerts pro-survival and anti-inflammatory actions. The results herein reported highlight the potential of Ru1 as pharmacological tool in neurodegenerative diseases and specially prove that the antioxidant properties of such compounds are likely the result of a non-trivial synergetic action involving the bioactive ligands in their chemical architectures.

Sphingosine 1-phosphate elicits a ROS-mediated proinflammatory response in human endometrial stromal cells via ERK5 activation.

Endometriosis is a chronic gynecological disease affecting ~10% women in the reproductive age characterized by the growth of endometrial glands and stroma outside the uterine cavity. The inflammatory process has a key role in the initiation and progression of the disorder. Currently, there are no available early diagnostic tests and therapy relies exclusively on symptomatic drugs, so that elucidation of the complex molecular mechanisms involved in the pathogenesis of endometriosis is an unmet need. The signaling of the bioactive sphingolipid sphingosine 1-phosphate (S1P) is deeply dysregulated in endometriosis. S1P modulates a variety of fundamental cellular processes, including inflammation, neo-angiogenesis, and immune responses acting mainly as ligand of a family of G-protein-coupled receptors named S1P receptors (S1PR), S1P1-5 . Here, we demonstrated that the mitogen-activated protein kinase ERK5, that is expressed in endometriotic lesions as determined by quantitative PCR, is activated by S1P in human endometrial stromal cells. S1P-induced ERK5 activation was shown to be triggered by S1P1/3 receptors via a SFK/MEK5-dependent axis. S1P-induced ERK5 activation was, in turn, responsible for the increase of reactive oxygen species and proinflammatory cytokine expression in human endometrial stromal cells. The present findings indicate that the S1P signaling, via ERK5 activation, supports a proinflammatory response in the endometrium and establish the rationale for the exploitation of innovative therapeutic targets for endometriosis.

The placenta in fetal death: Molecular evidence of dysregulation of inflammatory, proliferative and fetal protective pathways.

BACKGROUND: It is estimated that over 2 million cases of fetal death occur worldwide every year, but, despite the high incidence, several basic and clinical characteristics of this disorder are still unclear. Placenta is suggested to play a central role in fetal death. Placenta produces hormones, cytokines and growth factors that modulate functions of the placental-maternal unit. Fetal death has been correlated with impaired secretion of some of these regulatory factors. OBJECTIVE(S): The aim of the present study was to evaluate, in placentas collected from fetal death, the gene expression of inflammatory, proliferative and protective factors. STUDY DESIGN: Cases of fetal death in singleton pregnancy were retrospectively selected, excluding pregnancies complicated by fetal anomalies, gestational diabetes, intrauterine growth restriction and moderate to severe maternal diseases. A group of placentas collected from healthy singleton term pregnancies were used as controls. Groups were compared regarding maternal and gestational age, fetal sex and birth weight. Placental mRNA expression of inflammatory (IL-6), proliferative (Activin A, TGF-ß1) and regulatory (VEGF, VEGFR2, ATP-binding cassette (ABC) transporters ABCB1 and ABCG2, sphingosine 1-phosphate (S1P) signaling pathway) markers was conducted using real-time PCR. Statistical analysis and graphical representation of the data were performed using the GraphPad Prism 5 software. For the statistical analysis, Student's t-test was used, and P values < 0.05 were considered significant. RESULTS: Placental mRNA expression of IL-6 and VEGFR2 resulted significantly higher in the fetal death group compared to controls (P<0.01), while activin A, ABCB1 and ABCG2 expression resulted significantly lower (P<0.01). A significant alteration in the S1P signaling pathway was found in the fetal death group, with an increased expression of the specific receptor isoforms sphingosine 1-phosphate receptor 1, 3 and 4 (S1P1, S1P3, S1P4) and of sphingosine kinase 2 (SK2), one of the enzyme isoforms responsible for S1P synthesis (P<0.01). CONCLUSION: (s): The present study confirmed a significantly increased expression of placental IL-6 and VEGFR2 mRNA, and for the first time showed an increased expression of S1P receptors and SK2 as well as a decreased expression of activin A and of selected ATP-binding cassette transporters, suggesting that multiple inflammatory and protective factors are deranged in placenta of fetal death.

High levels of hypusinated eIF5A in leiomyoma and leiomyosarcoma pathologies: a possible novel therapeutic target.

RESEARCH QUESTION: Is the hypusinated form of the eukaryotic translation initiation factor 5A (EIF5A) present in human myometrium, leiomyoma and leiomyosarcoma, and does it regulate cell proliferation and fibrosis? DESIGN: The hypusination status of eIF5A in myometrial and leiomyoma patient-matched tissues was evaluated by immunohistochemistry and Western blotting as well as in leiomyosarcoma tissues by immunohistochemistry. Myometrial, leiomyoma and leiomyosarcoma cell lines were treated with N1-guanyl-1,7-diaminoheptane (GC-7), responsible for the inhibition of the first step of eIF5A hypunization, and the proliferation rate was determined by MTT assay; fibronectin expression was analysed by Western blotting. Finally, expression of fibronectin in leiomyosarcoma tissues was detected by immunohistochemistry. RESULTS: The hypusinated form of eIF5A was present in all tissues examined, with an increasing trend of hypusinated eIF5A levels from normal myometrium to neoplastic benign leiomyoma up to neoplastic malignant leiomyosarcoma. The higher levels in leiomyoma compared with myometrium were confirmed by Western blotting (P = 0.0046). The inhibition of eIF5A hypusination, with GC-7 treatment at 100 nM, reduced the cell proliferation in myometrium (P = 0.0429), leiomyoma (P = 0.0030) and leiomyosarcoma (P = 0.0044) cell lines and reduced the expression of fibronectin in leiomyoma (P = 0.0077) and leiomyosarcoma (P = 0.0280) cells. The immunohistochemical staining of leiomyosarcoma tissue revealed that fibronectin was highly expressed in the malignant aggressive (central) part of the leiomyosarcoma lesion, where hypusinated eIF5A was also highly represented. CONCLUSIONS: These data support the hypothesis that eIF5A may be involved in the pathogenesis of myometrial benign and malignant pathologies.

Novel Biotinylated Cu(II)-Phenanthroline Complexes: 2D and 3D Cytotoxic Activity and Mechanistic Insight.

The interest in the use of copper as a metal scaffold for the development of novel chemotherapeutics has considerably grown in recent years. This is mainly due to the relatively lower toxicity of copper complexes with respect to platinum drugs (i.e., cisplatin), the different mechanisms of action, and the cheaper cost. In the last decades, hundreds of copper-based complexes were developed and screened as anticancer agents, with the antesignanus of all compounds being copper bis-phenanthroline [Cu(phen)2]2+ developed by D.S. Sigman in the late 1990s. In particular, copper(phen) derivatives have been shown high interest in their capacity to interact with DNA by nucleobase intercalation. Here, we report the synthesis and chemical characterization of four novel copper(II) complexes functionalised with phenanthroline derivatives containing biotin. Biotin, also known as Vitamin B7, is involved in a series of metabolic processes, and its receptors are often overexpressed in many tumour cells. A detailed biological analysis including cytotoxicity in 2D and 3D, cellular drug uptake, DNA interaction, and morphological studies are discussed.

Sphingosine 1-phosphate pathway is dysregulated in adenomyosis.

RESEARCH QUESTION: Is sphingosine 1-phosphate (S1P) pathway involved in the process of fibrosis in adenomyosis? DESIGN: RNA was extracted from paraffin-embedded slices collected from the ectopic endometrium of patients with nodular adenomyosis (n = 27) and eutopic endometrium of healthy controls women (n = 29). Expression of genes involved in the metabolism and signalling of S1P, and actin-alpha-2 smooth muscle, encoded by ACTA2 gene, a gene involved in fibrogenesis, was evaluated by real-time polymerase chain reaction analysis. RESULTS: In adenomyotic samples, the expression of sphingosine kinase 1 (SPHK1), the enzyme responsible for the synthesis of S1P, and of S1P phosphatase 2 (SGPP2), the enzyme responsible for the conversion of S1P back to sphingosine, was lower (P = 0.0006; P = 0.0015), whereas that of calcium and integrin-binding protein 1, responsible for membrane translocation of SPHK1, was higher (P = 0.0001) compared with healthy controls. In S1P signalling, a higher expression of S1P receptor S1P3 (P = 0.001), and a lower expression of S1P2 (P = 0.0019) mRNA levels, were found compared with healthy endometrium. In adenomyotic nodules, a higher expression of ACTA2 mRNA levels were observed (P = 0.0001), which correlated with S1P3 levels (P = 0.0138). CONCLUSION: Present data show a profound dysregulation of the S1P signalling axis in adenomyosis. This study also highlights that the bioactive sphingolipid might be involved in the fibrotic tract of the disease, correlated with the expression of ACTA2, suggesting its role as novel potential biomarker of adenomyosis.

The TRPV1 Receptor Is Up-Regulated by Sphingosine 1-Phosphate and Is Implicated in the Anandamide-Dependent Regulation of Mitochondrial Activity in C2C12 Myoblasts.

The sphingosine 1-phosphate (S1P) and endocannabinoid (ECS) systems comprehend bioactive lipids widely involved in the regulation of similar biological processes. Interactions between S1P and ECS have not been so far investigated in skeletal muscle, where both systems are active. Here, we used murine C2C12 myoblasts to investigate the effects of S1P on ECS elements by qRT-PCR, Western blotting and UHPLC-MS. In addition, the modulation of the mitochondrial membrane potential (ΔΨm), by JC-1 and Mitotracker Red CMX-Ros fluorescent dyes, as well as levels of protein controlling mitochondrial function, along with the oxygen consumption were assessed, by Western blotting and respirometry, respectively, after cell treatment with methanandamide (mAEA) and in the presence of S1P or antagonists to endocannabinoid-binding receptors. S1P induced a significant increase in TRPV1 expression both at mRNA and protein level, while it reduced the protein content of CB2. A dose-dependent effect of mAEA on ΔΨm, mediated by TRPV1, was evidenced; in particular, low doses were responsible for increased ΔΨm, whereas a high dose negatively modulated ΔΨm and cell survival. Moreover, mAEA-induced hyperpolarization was counteracted by S1P. These findings open new dimension to S1P and endocannabinoids cross-talk in skeletal muscle, identifying TRPV1 as a pivotal target.

Phosphatidic Acid Stimulates Myoblast Proliferation through Interaction with LPA1 and LPA2 Receptors.

Phosphatidic acid (PA) is a bioactive phospholipid capable of regulating key biological functions, including neutrophil respiratory burst, chemotaxis, or cell growth and differentiation. However, the mechanisms whereby PA exerts these actions are not completely understood. In this work, we show that PA stimulates myoblast proliferation, as determined by measuring the incorporation of [3H]thymidine into DNA and by staining the cells with crystal violet. PA induced the rapid phosphorylation of Akt and ERK1/2, and pretreatment of the cells with specific small interferin RNA (siRNA) to silence the genes encoding these kinases, or with selective pharmacologic inhibitors, blocked PA-stimulated myoblast proliferation. The mitogenic effects of PA were abolished by the preincubation of the myoblasts with pertussis toxin, a Gi protein inhibitor, suggesting the implication of Gi protein-coupled receptors in this action. Although some of the effects of PA have been associated with its possible conversion to lysoPA (LPA), treatment of the myoblasts with PA for up to 60 min did not produce any significant amount of LPA in these cells. Of interest, pharmacological blockade of the LPA receptors 1 and 2, or specific siRNA to silence the genes encoding these receptors, abolished PA-stimulated myoblast proliferation. Moreover, PA was able to compete with LPA for binding to LPA receptors, suggesting that PA can act as a ligand of LPA receptors. It can be concluded that PA stimulates myoblast proliferation through interaction with LPA1 and LPA2 receptors and the subsequent activation of the PI3K/Akt and MEK/ERK1-2 pathways, independently of LPA formation.

Role of Sphingosine 1-Phosphate Signalling Axis in Muscle Atrophy Induced by TNFα in C2C12 Myotubes.

Skeletal muscle atrophy is characterized by a decrease in muscle mass causing reduced agility, increased fatigability and higher risk of bone fractures. Inflammatory cytokines, such as tumor necrosis factor-alpha (TNFα), are strong inducers of skeletal muscle atrophy. The bioactive sphingolipid sphingosine 1-phoshate (S1P) plays an important role in skeletal muscle biology. S1P, generated by the phosphorylation of sphingosine catalyzed by sphingosine kinase (SK1/2), exerts most of its actions through its specific receptors, S1P1-5. Here, we provide experimental evidence that TNFα induces atrophy and autophagy in skeletal muscle C2C12 myotubes, modulating the expression of specific markers and both active and passive membrane electrophysiological properties. NMR-metabolomics provided a clear picture of the deep remodelling of skeletal muscle fibre metabolism induced by TNFα challenge. The cytokine is responsible for the modulation of S1P signalling axis, upregulating mRNA levels of S1P2 and S1P3 and downregulating those of SK2. TNFα increases the phosphorylated form of SK1, readout of its activation. Interestingly, pharmacological inhibition of SK1 and specific antagonism of S1P3 prevented the increase in autophagy markers and the changes in the electrophysiological properties of C2C12 myotubes without affecting metabolic remodelling induced by the cytokine, highlighting the involvement of S1P signalling axis on TNFα-induced atrophy in skeletal muscle.

Antagonizing S1P3 Receptor with Cell-Penetrating Pepducins in Skeletal Muscle Fibrosis.

S1P is the final product of sphingolipid metabolism, which interacts with five widely expressed GPCRs (S1P1-5). Increasing numbers of studies have indicated the importance of S1P3 in various pathophysiological processes. Recently, we have identified a pepducin (compound KRX-725-II) acting as an S1P3 receptor antagonist. Here, aiming to optimize the activity and selectivity profile of the described compound, we have synthesized a series of derivatives in which Tyr, in position 4, has been substituted with several natural aromatic and unnatural aromatic and non-aromatic amino acids. All the compounds were evaluated for their ability to inhibit vascular relaxation induced by KRX-725 (as S1P3 selective pepducin agonist) and KRX-722 (an S1P1-selective pepducin agonist). Those selective towards S1P3 (compounds V and VII) were also evaluated for their ability to inhibit skeletal muscle fibrosis. Finally, molecular dynamics simulations were performed to derive information on the preferred conformations of selective and unselective antagonists.

Sphingosine 1-phosphate signaling axis mediates fibroblast growth factor 2-induced proliferation and survival of murine auditory neuroblasts.

Hearing loss affects millions of people in the world. In mammals the auditory system comprises diverse cell types which are terminally differentiated and with no regenerative potential. There is a tremendous research interest aimed at identifying cell therapy based solutions or pharmacological approaches that could be applied therapeutically alongside auditory devices to prevent hair cell and neuron loss. Sphingosine 1-phosphate (S1P) is a pleiotropic bioactive sphingolipid that plays key role in the regulation of many physiological and pathological functions. S1P is intracellularly produced by sphingosine kinase (SK) 1 and SK2 and exerts many of its action consequently to its ligation to S1P specific receptors (S1PR), S1P1-5. In this study, murine auditory neuroblasts named US/VOT-N33 have been used as progenitors of neurons of the spiral ganglion. We demonstrated that the fibroblast growth factor 2 (FGF2)-induced proliferative action was dependent on SK1, SK2 as well as S1P1 and S1P2. Moreover, the pro-survival effect of FGF2 from apoptotic cell death induced by staurosporine treatment was dependent on SK but not on S1PR. Additionally, ERK1/2 and Akt signaling pathways were found to mediate the mitogenic and survival action of FGF2, respectively. Taken together, these findings demonstrate a crucial role for S1P signaling axis in the proliferation and the survival of otic vesicle neuroprogenitors, highlighting the identification of possible novel therapeutical approaches to prevent neuronal degeneration during hearing loss.

Lysophosphatidic Acid Signaling Axis Mediates Ceramide 1-Phosphate-Induced Proliferation of C2C12 Myoblasts.

Sphingolipids are not only crucial for membrane architecture but act as critical regulators of cell functions. The bioactive sphingolipid ceramide 1-phosphate (C1P), generated by the action of ceramide kinase, has been reported to stimulate cell proliferation, cell migration and to regulate inflammatory responses via activation of different signaling pathways. We have previously shown that skeletal muscle is a tissue target for C1P since the phosphosphingolipid plays a positive role in myoblast proliferation implying a role in muscle regeneration. Skeletal muscle displays strong capacity of regeneration thanks to the presence of quiescent adult stem cells called satellite cells that upon trauma enter into the cell cycle and start proliferating. However, at present, the exact molecular mechanism by which C1P triggers its mitogenic effect in myoblasts is lacking. Here, we report for the first time that C1P stimulates C2C12 myoblast proliferation via lysophosphatidic acid (LPA) signaling axis. Indeed, C1P subsequently to phospholipase A2 activation leads to LPA1 and LPA3 engagement, which in turn drive Akt (protein kinase B) and ERK1/2 (extracellular signal-regulated kinases 1/2) activation, thus stimulating DNA synthesis. The present findings shed new light on the key role of bioactive sphingolipids in skeletal muscle and provide further support to the notion that these pleiotropic molecules might be useful therapeutic targets for skeletal muscle regeneration.

Ablation of S1P3 receptor protects mouse soleus from age-related drop in muscle mass, force, and regenerative capacity.

We investigated the effects of S1P3 deficiency on the age-related atrophy, decline in force, and regenerative capacity of soleus muscle from 23-mo-old male (old) mice. Compared with muscle from 5-mo-old (adult) mice, soleus mass and muscle fiber cross-sectional area (CSA) in old wild-type mice were reduced by ~26% and 24%, respectively. By contrast, the mass and fiber CSA of soleus muscle in old S1P3-null mice were comparable to those of adult muscle. Moreover, in soleus muscle of wild-type mice, twitch and tetanic tensions diminished from adulthood to old age. A slowing of contractile properties was also observed in soleus from old wild-type mice. In S1P3-null mice, neither force nor the contractile properties of soleus changed during aging. We also evaluated the regenerative capacity of soleus in old S1P3-null mice by stimulating muscle regeneration through myotoxic injury. After 10 days of regeneration, the mean fiber CSA of soleus in old wild-type mice was significantly smaller (-28%) compared with that of regenerated muscle in adult mice. On the contrary, the mean fiber CSA of regenerated soleus in old S1P3-null mice was similar to that of muscle in adult mice. We conclude that in the absence of S1P3, soleus muscle is protected from the decrease in muscle mass and force, and the attenuation of regenerative capacity, all of which are typical characteristics of aging.

CTGF/CCN2 exerts profibrotic action in myoblasts via the up-regulation of sphingosine kinase-1/S1P3 signaling axis: Implications in the action mechanism of TGFß.

The matricellular protein connective tissue growth factor (CTGF/CCN2) is recognized as key player in the onset of fibrosis in various tissues, including skeletal muscle. In many circumstances, CTGF has been shown to be induced by transforming growth factor beta (TGFß) and accounting, at least in part, for its biological action. In this study it was verified that in cultured myoblasts CTGF/CCN2 causes their transdifferentiation into myofibroblasts by up-regulating the expression of fibrosis marker proteins α-smooth muscle actin and transgelin. Interestingly, it was also found that the profibrotic effect exerted by CTGF/CCN2 was mediated by the sphingosine kinase (SK)-1/S1P3 signaling axis specifically induced by the treatment with the profibrotic cue. Following CTGF/CCN2-induced up-regulation, S1P3 became the S1P receptor subtype expressed at the highest degree, at least at mRNA level, and was thus capable of readdressing the sphingosine 1-phosphate signaling towards fibrosis rather than myogenic differentiation. Another interesting finding is that CTGF/CCN2 silencing prevented the TGFß-dependent up-regulation of SK1/S1P3 signaling axis and strongly reduced the profibrotic effect exerted by TGFß, pointing at a crucial role of endogenous CTGF/CCN2 generated following TGFß challenge in the transmission of at least part of its profibrotic effect. These results provide new insights into the molecular mechanism by which CTGF/CCN2 drives its biological action and strengthen the concept that SK1/S1P3 axis plays a critical role in the onset of fibrotic cell phenotype.

New insights into the role of sphingosine 1-phosphate and lysophosphatidic acid in the regulation of skeletal muscle cell biology.

Lysophospholipids are bioactive molecules that are implicated in the control of fundamental biological processes such as proliferation, differentiation, survival and motility in different cell types. Here we review the role of sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) in the regulation of skeletal muscle biology. Indeed, a wealth of experimental data indicate that these molecules are crucial players in the skeletal muscle regeneration process, acting by controllers of activation, proliferation and differentiation not only of muscle-resident satellite cells but also of mesenchymal progenitors that originate outside the skeletal muscle. Moreover, S1P and LPA are clearly involved in the regulation of skeletal muscle metabolism, muscle adaptation to different physiological needs and resistance to muscle fatigue. Notably, studies accomplished so far, have highlighted the complexity of S1P and LPA signaling in skeletal muscle cells that appears to be further complicated by their close dependence on functional cross-talks with growth factors, hormones and cytokines. Our increasing understanding of bioactive lipid signaling can individuate novel molecular targets aimed at enhancing skeletal muscle regeneration and reducing the fibrotic process that impairs full functional recovery of the tissue during aging, after a trauma or skeletal muscle diseases. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.

TGFß1 evokes myoblast apoptotic response via a novel signaling pathway involving S1P4 transactivation upstream of Rho-kinase-2 activation.

In view of its multiple detrimental effects, transforming growth factor ß1 (TGFß1) is recognized as critical negative regulator of skeletal muscle repair. Apoptosis of skeletal muscle precursor cells driven by TGFß1 contributes to the negative role exerted by the cytokine in tissue repair, although the underlying molecular mechanisms are still elusive. Herein we report the identification of a new signaling pathway, relying on Rho kinase-2 stimulation, subsequent to SMAD-dependent S1P4 up-regulation and transactivation via sphingosine kinase (SK)-2, that accounts for TGFß1-induced apoptosis in cultured myoblasts. S1P4-specific gene silencing reduced by almost 50% activation of caspase-3 and poly-ADP ribosyl transferase cleavage elicited by TGFß1. Moreover, the selective S1P4 antagonist CYM50358 also reduced the TGFß1 proapoptotic effects. By employing pharmacological and molecular biological approaches, the involvement of SK2 and ROCK2 in the transmission of the TGFß1 apoptotic action was also demonstrated. These results reinforce the notion that the SK/S1P axis plays a fundamental role in TGFß1 mode of action in skeletal muscle cells and, by disclosing a novel mechanism by which TGFß1 exerts its harmful action, pinpoint new molecular targets that in principle could be beneficial in the treatment of several skeletal muscle disorders or aging-dependent muscle atrophy.

Regulation of growth factor receptor degradation by ADP-ribosylation factor domain protein (ARD) 1.

ADP-ribosylation factor domain protein 1 (ARD1) is a 64-kDa protein containing a functional ADP-ribosylation factor (GTP hydrolase, GTPase), GTPase-activating protein, and E3 ubiquitin ligase domains. ARD1 activation by the guanine nucleotide-exchange factor cytohesin-1 was known. GTPase and E3 ligase activities of ARD1 suggest roles in protein transport and turnover. To explore this hypothesis, we used mouse embryo fibroblasts (MEFs) from ARD1-/- mice stably transfected with plasmids for inducible expression of wild-type ARD1 protein (KO-WT), or ARD1 protein with inactivating mutations in E3 ligase domain (KO-E3), or containing persistently active GTP-bound (KO-GTP), or inactive GDP-bound (KO-GDP) GTPase domains. Inhibition of proteasomal proteases in mifepristone-induced KO-WT, KO-GDP, or KO-GTP MEFs resulted in accumulation of these ARD1 proteins, whereas KO-E3 accumulated without inhibitors. All data were consistent with the conclusion that ARD1 regulates its own steady-state levels in cells by autoubiquitination. Based on reported growth factor receptor-cytohesin interactions, EGF receptor (EGFR) was investigated in induced MEFs. Amounts of cell-surface and total EGFR were higher in KO-GDP and lower in KO-GTP than in KO-WT MEFs, with levels in both mutants greater (p = 0.001) after proteasomal inhibition. Significant differences among MEF lines in content of TGF-ß receptor III were similar to those in EGFR, albeit not as large. Differences in amounts of insulin receptor mirrored those in EGFR, but did not reach statistical significance. Overall, the capacity of ARD1 GTPase to cycle between active and inactive forms and its autoubiquitination both appear to be necessary for the appropriate turnover of EGFR and perhaps additional growth factor receptors.

Sphingosine-1-phosphate receptor 3 is a non-hormonal target to counteract endometriosis-associated fibrosis.

OBJECTIVE: To study the molecular mechanisms responsible for fibrosis in endometriosis by investigating whether the protein expression levels of sphingosine-1-phosphate receptor 3 (S1PR3), one of the five specific receptors of the bioactive sphingolipid sphingosine-1-phosphate (S1P), correlate with fibrosis extent in endometriotic lesions and which are the cellular mechanisms involved in this process. DESIGN: Case-control laboratory study and cultured endometriotic cells. SETTING: University research institute and university hospital. PATIENT(S): A total of 33 women, with and without endometriosis, were included in the study. INTERVENTIONS(S): Endometriotic lesions were obtained from women with endometriosis (ovarian endometrioma, n = 8; deep infiltrating endometriosis, n = 15; [urological n = 5, gastrointestinal n = 6, and posterior n = 4]) and control endometrium from healthy women, n = 10, by means of laparoscopic and hysteroscopic surgery. The expression of S1PR3 was evaluated using immunohistochemistry and the extent of fibrosis was assessed using Masson's trichrome staining. Human-cultured epithelial endometriotic 12Z cells were used to evaluate the mechanisms involved in the profibrotic effect of S1PR3 activation. MAIN OUTCOME MEASURE(S): The expression of S1PR3 in endometriotic lesions is positively correlated with endometriosis-associated fibrosis. In addition, S1P induced epithelial-mesenchymal transition (EMT) and fibrosis in epithelial endometriotic cells. Using RNA interference and pharmacological approaches, the profibrotic effect of S1P was shown to rely on S1PR3, thus unveiling the molecular mechanism implicated in the profibrotic action of the bioactive sphingolipid. RESULT(S): The protein expression levels of S1PR3 were significantly augmented in the glandular sections of endometrioma and deep infiltrating endometriosis of different localizations with respect to the control endometrium and positively correlated with the extent of fibrosis. Sphingosine-1-phosphate was shown to have a crucial role in the onset of fibrosis in epithelial endometriotic cells, stimulating the expression of EMT and fibrotic markers. Genetic approaches have highlighted that S1PR3 mediates the fibrotic effect of S1P. Downstream of S1PR3, ezrin and extracellular-signal-regulated kinases 1 and 2 signaling were found to be critically implicated in the EMT and fibrosis elicited by S1P. CONCLUSION(S): Sphingosine-1-phosphate receptor 3 may represent a possible innovative pharmacological target for endometriosis.

Sphingosine 1-phosphate signaling axis mediates neuropeptide S-induced invasive phenotype of endometriotic cells.

Endometriosis is a chronic gynecological syndrome characterized by endometrial cell invasion of the extra-uterine milieu, pelvic pain and infertility. Treatment relies on either symptomatic drugs or hormonal therapies, even though the mechanism involved in the onset of endometriosis is yet to be elucidated. The signaling of sphingolipid sphingosine 1-phosphate (S1P) is profoundly dysregulated in endometriosis. Indeed, sphingosine kinase (SK)1, one of the two isoenzymes responsible for S1P biosynthesis, and S1P1, S1P3 and S1P5, three of its five specific receptors, are more highly expressed in endometriotic lesions compared to healthy endometrium. Recently, missense coding variants of the gene encoding the receptor 1 for neuropeptide S (NPS) have been robustly associated with endometriosis in humans. This study aimed to characterize the biological effect of NPS in endometriotic epithelial cells and the possible involvement of the S1P signaling axis in its action. NPS was found to potently induce cell invasion and actin cytoskeletal remodeling. Of note, the NPS-induced invasive phenotype was dependent on SK1 and SK2 as well as on S1P1 and S1P3, given that the biological action of the neuropeptide was fully prevented when one of the two biosynthetic enzymes or one of the two selective receptors was inhibited or silenced. Furthermore, the RhoA/Rho kinase pathway, downstream to S1P receptor signaling, was found to be critically implicated in invasion and cytoskeletal remodeling elicited by NPS. These findings provide new information to the understanding of the molecular mechanisms implicated in endometriosis pathogenesis, establishing the rationale for non-hormonal therapeutic targets for its treatment.

Imaging and molecular features of adenomyosis after menopause.

OBJECTIVES: To explore the imaging features and the molecular characterization of adenomyosis after menopause. STUDY DESIGN: An observational cross-sectional study was performed in a group of postmenopausal patients undergoing a transvaginal ultrasound (TVUS) (n = 468). Among those presenting the US criteria for adenomyosis, also confirmed by magnetic resonance imaging (MRI), previous menstrual symptoms, gynecological and obstetric history were reviewed. In a subgroup undergoing hysterectomy, uterine specimens were analyzed by histology and expression of genes implicated in the epithelial-mesenchymal transition, inflammation and fibrosis, including the sphingosine-1-phosphate (S1P) pathway, was evaluated and compared to matched non-menopausal adenomyosis specimens. MAIN OUTCOME MEASURES: Direct and indirect US features of adenomyosis according to Morphological Uterus Sonographic Assessment at TVUS. Molecular characterization of postmenopausal versus pre-menopausal adenomyosis samples. RESULTS: According to TVUS and MRI, adenomyosis was identified in 49 patients (10.4 %). On US, diffuse adenomyosis was the most common phenotype, whereas internal adenomyosis with diffuse pattern and asymmetric type was the most prevalent on MRI. Molecular analysis showed that adenomyosis lesions express markers of epithelial-mesenchymal transition, inflammation and fibrosis also in postmenopausal women. By comparing the results with those from pre-menopausal samples, the expression of α smooth muscle actin (αSMA), a marker of fibrosis, was significantly greater after menopause, and altered S1P catabolism and signaling were observed. CONCLUSIONS: Adenomyosis may be identified in postmenopausal women by imaging, either TVUS or MRI, and fibrosis is one of the key features on molecular analysis.