Silvia Di Tommaso

The Drosophila fragile X mental retardation protein participates in the piRNA pathway

ABSTRACT RNA metabolism controls multiple biological processes, and a specific class of small RNAs, called piRNAs, act as genome guardians by silencing the expression of transposons and repetitive sequences in the gonads. Defects in the piRNA pathway affect genome integrity and fertility. The possible implications in physiopathological mechanisms of human diseases have made the piRNA pathway the object of intense investigation, and recent work suggests that there is a role for this pathway in somatic processes including synaptic plasticity. The RNA-binding fragile X mental retardation protein (FMRP, also known as FMR1) controls translation and its loss triggers the most frequent syndromic form of mental retardation as well as gonadal defects in humans. Here, we demonstrate for the first time that germline, as well as somatic expression, of Drosophila Fmr1 (denoted dFmr1), the Drosophila ortholog of FMRP, are necessary in a pathway mediated by piRNAs. Moreover, dFmr1 interacts genetically and biochemically with Aubergine, an Argonaute protein and a key player in this pathway. Our data provide novel perspectives for understanding the phenotypes observed in Fragile X patients and support the view that piRNAs might be at work in the nervous system.

Selective genetic analysis of myoma pseudocapsule and potential biological impact on uterine fibroid medical therapy

Objective: Mutations in Mediator Complex Subunit 12 (MED12) gene are typical genomic aberrations, commonly detected in a high percentage of uterine leiomyomas (ULs). The aim of this investigation was to define the fibroid or non-tumor origin of uterine leiomyoma pseudocapsule (PC) surrounding fibroids and its possible therapeutic targets in uterine fibroid management. Research design and methods: A non-randomized observational study was performed on 36 women, not subjected to any previous drug treatment, undergoing laparoscopic intracapsular myomectomy. Specimens of myometrium (UM), ULs and corresponding PCs were sampled to analyze MED12 gene status, by direct sequencing of exon 2. Main outcome measures: Defining the status of MED12 gene in PCs associated to ULs harboring mutations. Results: PCs always showed a wild type MED12 gene status, even when associated to a UL harboring a specific MED12 aberration. Conclusions: The wild-type status of MED12 gene in the PCs indicates the non-tumoral origin of this structure: it appears as a protective structure for the healthy tissue that could enhance regenerative mechanisms. The limitations of this study, as the restrained number of patients, will be solved in the future extending the analysis to a larger cohort of women, as tester of such pharmacological treatments on PC.

The “Special” crystal-Stellate System in Drosophila melanogaster Reveals Mechanisms Underlying piRNA Pathway-Mediated Canalization

The Stellate-made crystals formation in spermatocytes is the phenotypic manifestation of a disrupted crystal-Stellate interaction in testes of Drosophila melanogaster. Stellate silencing is achieved by the piRNA pathway, but many features still remain unknown. Here we outline the important role of the crystal-Stellate modifiers. These have shed light on the piRNA pathways that defend genome integrity against transposons and other repetitive elements in the gonads. In particular, we illustrate the finding that HSP90 participates in the molecular pathways of piRNA production. This observation has relevance for the mechanisms underlying the evolutionary canalization process.

A Proteomic Analysis of Human Uterine Myoma

Uterine leiomyoma is a benign smooth muscle tumor characterized by a high incidence in women of reproductive age. The aetiology of this tumor is still unknown but established risk factors include high levels of female hormones, family history, African ancestry, early age of menarche and obesity. Here, to identify proteomic features associated with this tumor type, we performed a liquid chromatography-mass spectrometry (LC-MS/MS) analysis of uterine myomas. The identified proteins were subjected to a gene ontology analysis to generate biological functions, molecular processes, and protein networks that were relevant to the uploaded dataset. Pathway-based analysis was an effective approach to investigate the molecular mechanisms underlying the disease and to create biological hypotheses about regulation of our proteins including the identification of upstream regulators and main protein nodes. Moreover, proteomic and in silico data were combined with immunohistochemistry and western blotting to identify a group of proteins representative of some selected pathways, with a dysregulated expression in myoma, pseudocapsule, and normal myometrium samples. Based on these results, we confirmed the over-expression of extracellular matrix components, and estrogen and progesterone receptors in uterine myomas, and proposed biological networks, canonical pathways and functions that may be relevant to the pathophysiology of this tumor.

A Qualitative and Quantitative Study of the Innervation of the Human Non Pregnant Uterus

Human female reproductive system is closely dependent by hormonal stimulation. Anyway it is now commonly stated that autonomic innervation system regulates, along with hormonal stimulation, the uterine physiology. Cholinergic and adrenergic innervations have a critical role in mediating input to the uterus, but other neurotransmitters and neuropeptides exist that influence uterine physiology, as well. In the present investigation, we analyzed the uterine distribution of a large set of neurotransmitters, focusing on adrenergic, noradredenergic, acetylcholine (AChE) positive, dopaminergic, serotoninergic and peptidergic neurofibers; among these latter, we focused on those releasing prolattine, enkephalines (ENKs), Vasoactive Intestinal Polypeptide (VIP), substance P (SP) and oxytocine. Authors demonstrate the differential localization of these neurofibers in non pregnant uterine fundus, corpus and cervix, sampling myometrial assays of 31 patients submitted to hysterectomy. In fundus uteri, we observed a prevalence of prolactinergic (32.1 ± 1.4 Conventional Unit, C.U.) and adrenergic (36.4 ± 4.5 C.U.) neurofibers; in uterine body VIP positive neurofibers (32.6 ± 4.8 C.U.) and prolactinergic neurofibers (30.3 ± 1.2 C.U.) were the most represented. In uterine cervix, we detected the highest concentration of all the neurofibers analysed, with enkephalinergic neurofibers (94 ± 1.7 C.U.), oxitocinergic neurofibers (72.1 ± 5.1 C.U.), SP positive neurofibers (66.1 ± 4.4 C.U.), acetylcholine positive neurofibers (64.5± 3.6 C.U.), serotoninergic neurofibers (56.4 ± 3.9 C.U.) and VIP positive neurofibers (58.3 ± 5.2 C.U.) being the most expressed. This study demonstrates that uterine cervix harbors a higher concentration of almost all neurotransmitters, compared to the other two uterine anatomic sites. The uterine cervix is largely involved during pregnancy and labor, and the rich neurotransmitters density could contribute to confer to the cervix a proper potential plasticity, necessary for pregnancy and labour.

Novel mutants of the aubergine gene

ABSTRACT Aubergine is an RNA-binding protein of the Piwi clade, functioning in germline in the piRNA pathway that silences transposons and repetitive sequences. Several mutations of this gene exist, but they mostly result in truncated proteins or correspond to mutations that also affect neighboring genes. We have generated complete aubergine knock-out mutants that do not disrupt the neighboring genes. These novel mutants are characterized by PCR and sequencing. Their nature is confirmed by female sterility and by the presence of crystals in testes, common to the aubergine loss of function mutations. These mutants provide novel and more appropriate tools for the study of the piRNA pathway that controls genome stability.

NEUROTRANSMITTERS AND NEUROPEPTIDES EXPRESSION IN THE UTERINE SCAR AFTER CESAREAN SECTION.

Peptides and neuropeptides influence the uterine disorders of healing or cicatrization, chronic pelvic pain and disorder of pregnancy, labor and puerperium. They also promote changes in the lower uterine segment (LUS) during pregnancy, labor and delivery. We investigated the tissue quantity of neurotensin (NT), neuropeptide tyrosin (NPY) and Protein Gene Product 9.5 (PGP 9.5) in women submitted to elective cesarean section (CS) and urgent CS. During surgery, authors biopsied tissue samples of vesico-uterine space (VUS) to detect nerve fibers, and compared them. VUS samples from 106 patients have been evaluated with light microscopy, immunochemistry and Immunohistochemistry, and finally by Quantimet Leica analyzer software. Significantly higher amount of nerve fibers, containing NT, NPY and PGP 9.5 have been found in VUS tissue samples obtained during the first elective CS and during the first urgent CS were respectively 5±0.7, 7±0.6 and 5±0.9 CU and 2.5±0.5, 3.6±0.4 and 3.5±0.9 CU (p<0.05). This neurotransmitter reduction should indicate the inflammatory damage of cervical tissue for LUS over distension in dystocic-prolonged labor before CS. These results may be correlated with the decrease of NT, NPY and PGP 9.5, responsible for an optimal healing and LUS functions. In our opinion, the presence of neuropeptides reduction in uterine samples of women undergoing urgent CS may be due to a prolonged fetal head station in LUS, with a tissue denervation, in consequence of both overdistension and inflammatory process of the dystocic LUS.

Uterine-preserving operative therapy of uterus myomatosus

Uterine myomas are the most frequent benign tumours of the uterus in women of childbearing age. Although uterine fibroids cause symptoms in only 20–50 % of cases, if present they may cause abnormal uterine bleeding, pain, and infertility.

LAMININ AND COLLAGEN IV: TWO POLYPEPTIDES AS MARKER OF DYSTOCIC LABOR.

Collagen IV and Laminin are localized in cells and tissue of numerous human organs including the uterus, where these polypeptides control either age changes, or uterus growth in pregnancy, or ripening and dilatation in labor. Authors examined the polypeptides distribution of collagen IV and Laminin in the human pregnant uterus, in normal and dystocic labor, to clarify their physiologic role, by distribution and/or their changes in prolonged dystocic labor. We collected lower uterine segment (LUS) fragments during cesarean section (CS); these biopsies were treated with basic morphological staining for the observation of microscopic- anatomic details. Other samples were processed with immunohistochemical staining for collagen IV and for membrane bound Laminin. All morphological and immunochemical results were analyzed with quantitative analysis of images and statistical analysis of data. Both Collagen IV and Laminin show changes in the pregnant uterus before 4 hours of full cervical dilatation in patients after 4 hours. All the three types of the human uterine cells, mucosal, submucosal and smooth muscular cells, are more reduced in LUS after 4 hours of cervical dilatation in dystocic labor. The connective tissues (including fibroblast) show the most evident changes in the dystocic LUS, collagen IV and laminin changes during cervical dilatation in prolonged dystocic labor, with a decreased elasticity with increased roughness and dryness. The LUS anatomical modifications during labor can be the cause of pathological changes in protracted dystocic labor. In the dystocic labor that lasts more than 4 hours from the complete cervical ripening and dilatation, the laminin and collagen IV concentration reduces in the LUS tissue. In dystocic labor, delivery should be completed before the 3 hours of full dilation, to avoid a reduction of laminin and collagen IV and a worsening of LUS healing for the next pregnancy.