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Upcoming Seminars

Paolo Bernardi, MD - "The dual life of mitochondrial F-ATP synthase"

Full Professor, Department of Biomedical Sciences, University of Padova, Italy
When Oct 22, 2019
from 12:00 PM to 01:00 PM
Where Tigem, Vesuvius Auditorium
Contact Name
Contact Phone 081-19230659
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Abstract
Mitochondria can undergo a Ca2+-dependent increase of inner membrane permeability (the permeability transition, PT) to solutes with mass up to about 1.5 kDa. The PT, which is favored by oxidative stress and inhibited by matrix H+, Mg2+ and adenine nucleotides, is mediated by opening of a high-conductance channel, the PT pore (PTP) or mitochondrial megachannel (MMC). The molecular identity of the MMC/ PTP remains a point of controversy, in particular about whether it can originate from a Ca2+-dependent conformational change of the energy-conserving  F1FO (F)-ATP synthase. To address this question we have used two complementary strategies. In the first, we have produced selective mutants of F-ATP synthase and assessed the consequences of the mutations on Ca2+-sensitivity, inhibition by H+ and modulation by specific reagents of the MMC/PTP. In the second strategy, we have employed highly pure and stable F-ATP synthase from large-scale preparations from bovine hearts. When the latter was incorporated into preformed liposomes, ATP hydrolysis generated a H+ gradient that could be dissipated by Ca2+. Ca2+ elicited currents matching those of the MMC/PTP when the same preparation was incorporated into planar lipid bilayers. Currents were fully reversible, and were inhibited by Mg2+ and adenine nucleotides but not by inhibitors of the adenine nucleotide translocase and of the voltage-dependent anion channel. Taken together our findings resolve the long-standing mystery of the MMC/PTP and demonstrate that Ca2+ can transform the energy-conserving F-ATP synthase into an energy-dissipating device. I will discuss recent advances that may resolve apparent discrepancies in the literature, and hopefully provide a frame to understand this complex and fascinating problem of mitochondrial biology.

 

Paolo Comoglio, MD - "Cancer of Unknown Primary (CUP): the archetype of metastatic disease"

Dean Candiolo Cancer Institute, Director of Molecular Therapeutics and Exploratory Research, Candiolo, (TO), Italy
When Nov 12, 2019
from 12:00 PM to 01:00 PM
Where Tigem, Vesuvius Auditorium
Contact Name
Contact Phone 081-19230659
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Abstract
Cancer of Unknown Primary (CUP) is an obscure metastatic disease characterized by multiple metastases in the absence of a clinically detectable, anatomically defined, primary tumor. CUPs share common traits: (i) early dissemination; (ii) unpredictable organ distribution; (iii) lack of tissue-specific differentiation markers; and (iv) poor prognosis. No consensus has been reached whether CUPs are simply generated from cancers that cannot be detected or if they are the manifestation of a still unknown nosologic entity.
The complete expression and genetic profiles of multiple synchronous and spatially distinct metastases harvested at ‘warm’ autopsy of a CUP patient were astonishingly singular. The whole exome analysis yielded a high number of mutations present in all metastases (‘fully shared’); additional mutations (‘partially shared’) accumulated one after another in a series, and few ‘private’ mutations were unique to each metastasis. Surprisingly, the phylogenetic trajectory linking CUP metastases was atypical, depicting a common ‘stream’, sprouting a series of linear ‘brooks’, at variance from the extensive branched evolution observed in metastases from most cancers  of known origin.
In collaboration with the Laboratory of Carla Boccaccio, we isolated from a panel of CUP patients tumor-initiating cells, growing as long-term propagating tridimensional colonies (‘agnospheres’). Agnospheres retain the genetic landscapes of their respective original human tumors, and display common distinctive features such as proliferative autonomy in vitro and the ability to rapidly disseminate, recapitulating the whole metastatic CUP cascade into multiple organs.
Taken together these observations strongly suggest that CUP metastasis result from a novel ‘yet unclear’ pathological entity.

Alessandra Recchia, PhD - "Modelling the CRISPR/Cas9 system to correct monogenic disorders"

Assistant Professor of Molecular Biology, Department of Life Sciences, University of Modena and Reggio Emilia, Italy
When Nov 18, 2019
from 12:00 PM to 01:00 PM
Where Tigem, Vesuvius Auditorium
Contact Name
Contact Phone 081-19230659
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Abstract
The CRISPR/Cas9 system is an effective genomic scissor guided by a short guide RNA to cleave specific DNA target sequences. The Cas9 introduces double strand breaks into the target gene, stimulating the cell’s DNA repair mechanisms of homology-directed repair and non-homologous end joining. Triggering these cellular mechanisms to purposely edit the gene of interest, CRISPR/Cas9 technology has earned a tremendous impact on genetic manipulation. For its simplicity, CRISPR/Cas9 has been studied and applied the most by scientists and clinicians and also proposed as a gene therapy tool for monogenic disorder. In this seminar I will present you our experience on CRISPR/Cas9 applications to tackle monogenic disorders. Employing different delivery systems and different SpCas9 variants, I will report correction of genetic defects ex vivo, in patients’ cell, and in vivo in preclinical model of dominant retinitis pigmentosa.

Francesca Carlomagno, MD, PhD - "Links Between Cell Cycle Control and Iron Metabolism"

Full Professor, IEOS c/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Universita' degli Studi di Napoli Federico II
When Dec 10, 2019
from 12:00 PM to 01:00 PM
Where Tigem, Vesuvius Auditorium
Contact Name
Contact Phone 081-19230659
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Abstract
Iron is crucial for many enzymes involved in DNA replication and for dNTPs synthesis. Indeed, limited iron availability affects cell proliferation inducing G1 arrest in order to avoid replication stress and DNA damage. NCOA4 is an iron-sensing protein that is stabilized in low iron conditions to promote ferritin degradation. Interestingly, NCOA4 exerts also a negative control on DNA replication origin activation in iron deficiency conditions in order to maintain genome stability. Thus, in DFO treated cells we observed increased binding of NCOA4 to MCM2-7 and to chromatin, and in particular to canonical DNA replication origins.  Indeed, in low iron conditions NCOA4-depleted HeLa cells (shNCOA4) activated more DNA replication origins than control cells showing reduced inter-origin distance and decreased fork rate with signs of replication stress.  Unscheduled DNA replication with associated signs of replication stress observed in HeLa-shNCOA4 cells lead to activation of a DNA Damage Response with phosphorylation of ATR, CHK1 and gamma-H2AX, permanent cell cycle arrest and reduced cell survival. Consistently, NCOA4 null mice displayed a decreased tolerance to tissue insults such as Dextran Sulfate-induced acute colitis with decreased proliferating crypts (eg pH3 positive cells) and increased DNA damage (eg pCHK2 positive cells) and apoptotic cells (eg Caspase 3 positive cells), reflecting an overall impairment of intestinal cell renewal. Collectively, our data describe a new cellular response activated in iron deficiency that exploit NCOA4 protein as a cell proliferation brake, to align DNA replication origin activation and iron fluctuations in order to avoid DNA replication stress.