Anna Gargiulo

miR-23a, miR-24 and miR-27a protect differentiating ESCs from BMP4-induced apoptosis

Numerous studies have indicated that BMP4 signaling is involved in the regulation of the early steps of development. In mouse embryonic stem cells (ESCs), BMP4 is crucial to sustain pluripotency and blocks differentiation towards neural fate. Here, through a systematic analysis of miRNAs in ESCs, we establish that BMP4 signaling regulates miR-23a, 27a and 24-2, through the recruitment of phospho-Smads at the promoter of the gene encoding this miRNA cluster. Suppression of miR-23a/b, 27a/b and 24 does not affect self-renewal or pluripotency, but induces an evident change of ESC differentiation, with a significant increase of the cells undergoing apoptosis after the transition from ESCs to epiblast stem cells (EpiSCs). BMP4 has been previously reported to cause apoptosis during ESC differentiation. By blocking BMP4 signaling, we completely prevent the apoptosis induced by suppression of the miRs. This suggests that the effects of miR suppression are the result of enhanced BMP4 signaling. This hypothesis is further supported by the observation that Smad5, the transcription factor downstream of the BMP4 receptor, is targeted by the miRNAs of the 23a and 23b clusters. Altogether, our results highlight the existence of a regulatory loop, involving Smad5 and the miR-23a clusters, that modulates the apoptotic response of ESCs to BMP4.

Fe65 matters: New light on an old molecule

The discovery that the main constituents of amyloid deposits, characteristic of Alzheimer neuropathology, derive from the proteolytic processing of the membrane precursor amyloid precursor protein (APP) is one of the milestones of the research history of this disease. Despite years of intense studies, the functions of APP and of its amyloidogenic processing are still under debate. One focus of these studies was the complex network of protein–protein interactions centered at the cytosolic domain of APP, which suggests the involvement of APP in a lively signaling pathway. Fe65 was the first protein to be demonstrated to interact with the APP cytodomain. Starting from this observation, a large body of data has been gathered, indicating that Fe65 is an adaptor protein, which binds numerous proteins, further than APP. Among these proteins, the crosstalk with Mena, mDab, and Abl suggested the involvement of the Fe65–APP complex in the regulation of cell motility, with a relevant role in differentiation and development. Other partners, like the histone acetyltransferase Tip60, indicated the possibility that the nuclear fraction of Fe65 could be involved in gene regulation and/or DNA repair.

Nutritional Limitation Sensitizes Mammalian Cells to GSK-3β Inhibitors and Leads to Growth Impairment

The serine/threonine kinase GSK-3β was initially described as a key enzyme involved in glucose metabolism, but it is now known to regulate a wide range of biological processes, including proliferation and apoptosis. We previously reported a transformation-dependent cell death induced by glucose limitation in K-ras-transformed NIH3T3. To address the mechanism of this phenomenon, we analyzed GSK-3β regulation in these cells in conditions of high versus low glucose availability. We found that glucose depletion caused a marked inhibition of GSK-3β through posttranslational mechanisms and that this inhibition was much less pronounced in normal cells. Further inhibition of GSK-3β with lithium chloride, combined with glucose shortage, caused specific activation of AMP-activated protein kinase and significant suppression of proliferation in transformed but not normal cells. The cooperative effect of lithium and low glucose availability on cell growth did not seem to depend exclusively on ras pathway activation because two human cell lines, A549 and MDA-MB-231, both harboring an activated ras gene, showed very different sensitivity to lithium. These findings thus provide a rationale to further analyze the biochemical bases for combined glucose deprivation and GSK-3β inhibition as a new approach to control transformed cell growth.

Hmga2 is necessary for Otx2-dependent exit of embryonic stem cells from the pluripotent ground state

BackgroundA crucial event in the differentiation of mouse embryonic stem cells (ESCs) is the exit from the pluripotent ground state that leads to the acquisition of the ‘primed’ pluripotent phenotype, characteristic of the epiblast-like stem cells (EpiLCs). The transcription factors Oct4 and Otx2 play a key role in this phenomenon. In particular, Otx2 pioneers and activates new enhancers, which are silent in ESCs and which control the transcription of genes responsible for the acquisition of the EpiLC phenotype. An important point that remains to be addressed is the mechanism through which Otx2 engages the new enhancers and stably associates with them.Hmga2 is a member of the high-mobility group family of proteins, non-histone components of chromatin whose expression is high during embryogenesis and becomes low or undetectable in adults. Its high expression during embryogenesis suggests that Hmga2 fulfills important roles in development.ResultsHere, we demonstrate that Hmga2 accumulates soon after the induction of ESC differentiation. Its suppression hampers the exit of ESCs from the pluripotent ground state and their differentiation into EpiLCs. Mechanistically, Hmga2 controls the differentiation process by cooperating with Otx2 in the pioneering of new enhancers. In Hmga2 null induced pluripotent stem cells we observe that Otx2 fails to regulate its target genes upon the induction of differentiation. Hmga2 associates to Otx2-bound loci in EpiLCs, and in Hmga2 KO cells Otx2 is unable to engage and activate the new enhancers, thus indicating that Hmga2 is required for the binding of Otx2 to its cis-elements. We find that this mechanism also operates on the Hmga2 gene, which is one of the targets of Otx2, thus indicating the existence of a positive feedback loop.ConclusionsOur findings reveal a novel mechanism necessary for the exit of ESCs from the pluripotent ground state. Upon the induction of ESC differentiation, Otx2 alone or in combination with Oct4 engages new enhancers, which are silent in undifferentiated ESCs. The Hmga2 gene is activated by Otx2 and Hmga2 protein binds to the enhancers targeted by Otx2, thus facilitating the engagement and/or the stable association of Otx2. Therefore, our results demonstrate that Hmga2 is a key element of the regulatory network that governs the exit of ESCs from the pluripotent ground state.

A comparison between pro-anorexia and non-suicidal self-injury blogs: From symptom-based identity to sharing of emotions

From a psychodynamic perspective, this paper presents a comparison between pro-anorexia (pro-Ana) and non-suicidal self-injury (NSSI) blogs, which are all built on the basis of a shared, symptom-based identity. A cluster analysis was performed on 40 Italian blogs through T-Lab software to find dimensions of meaning. Four thematic clusters emerged, which, using factorial mapping, fall onto three axes: from closure on the symptom to recounting the malaise; the pain: from psychic to social; from failure of primary relationships to patterns of relational dysfunction. The two types of blog differ both in terms of content and function. The proAna blogs tend to reinforce a portrayal of anorexia as a lifestyle choice that leaves little space for anything or anyone else. The NSSI blogs reveal aspects of relational support and an ambivalent attitude to pain and discomfort. The different dimensions provide a springboard for discussion on clinical implications.

Italian Validation of the Capacity to Love Inventory: Preliminary Results

Introduction: Within a wider international research project aimed at operationalize the psychodynamic construct of capacity to love (Kernberg, 2011), the Capacity to Love Inventory (CTL-I) is a 41-items self-report questionnaire assessing six dimensions: interest in the life project of the other, basic trust, gratitude, common ego ideal, permanence of sexual passion, loss, and mourning. Objectives: The study is aimed at validating the Italian version of the CTL-I. Method: A total sample of 736 Italian non-clinical adults was administered a checklist assessing socio-demographic variables, and the CTL-I. A Confirmatory Factor Analyses (CFA) was conducted to examine the construct validity of the Italian version of the CTL-I. Only a part of the total sample (320 participants) was administered an additional series of concurrent measures in order to investigate the convergent validity of the CTL-I. Correlations with measures of socio-sexual orientation, quality of romance relations, and psychopathological questionnaires were examined through Pearsons correlation coefficients. Results: CFA results suggested that the Italian CTL-I fully replicated the six-factor structure of the original CTL-I. Cronbachs alpha index provided satisfactory results for all subscales and the correlations with concurrent measures were in expected direction. Conclusion: The results showed promising psychometric characteristics of the Italian version of CTL-I. Implications of the feasibility of the instrument in clinical and psychotherapeutic settings are discussed.

Incidere i limiti. Dalla Body Art all’autolesionismo, considerazioni psicodinamiche sul corpo all’epoca del postumano

Our work questions the theme of corporeity from a psychoanalytic framework, moving from the modalities with which the body experience sets itself at the base of thought considering the variations of psychic functions related to the destructured and restructured experiences of the body that appear nowadays on the contemporaneous scene. In different fields, the one of clinical psychology through the Non-suicidal Self-injury and the one of the art through the extreme form of Body art, will be reflected on the experience of the limit, moving from corporeal borders, that posthuman challenges.