The importance of humanized yeast to better understand the role of Bcl-2 family in apoptosis : finding of novel therapeutic opportunities

The Bcl-2 protein family plays a central role in mitochondrial membrane permeabilization. This event and the ensuing release of cytochrome c are decisive in the apoptotic cascade. Therefore, a better knowledge of these processes and their regulation will probably lead to the development of novel therapeutic strategies for treatment of apoptosis-related diseases. However, the mode of action of Bcl-2 protein family and its regulation are not completely understood. Yeast has proved to be a powerful tool to investigate the molecular aspects of several biological processes, including the steps of the apoptotic cascade involving mitochondria. The fact that yeast does not have obvious homologues of the mammalian Bcl-2 family proteins and that these proteins conserve some of their molecular and biochemical functions when expressed in yeast favours the use of this simpler model system to unravel some of the functions of this family. In this review we attempt to encompass the current knowledge regarding Bcl-2 family mode of action and regulation obtained using the yeast model system. Moreover, we discuss how this model system can be used in the future to gain new understanding about the intricate mechanisms of Bcl-2 family protein regulation, and highlight novel therapeutic targets revealed by this system. We believe that the studies here summarized also provide a proof of principle of yeast as an important tool to elucidate some of the complex mechanisms of apoptotic cell death in higher eukaryotes.R. D. Silva (SFRH/BD/23774/2005) have a fellowship from Fundação para a Ciência e Tecnologia, Portugal. This work was supported by a FCT funded project (PTDC/BIA-BCM/ 69448/2006)

Modulation of bax mitochondrial insertion and induced cell death in yeast by mammalian protein kinase calpha

Protein kinase Cα (PKCα) is a classical PKC isoform whose involvement in cell death is not completely understood. Bax, a major member of the Bcl-2 family, is required for apoptotic cell death and regulation of Bax translocation and insertion into the outer mitochondrial membrane is crucial for regulation of the apoptotic process. Here we show that PKCα increases the translocation and insertion of Bax c-myc (an active form of Bax) into the outer membrane of yeast mitochondria. This is associated with an increase in cytochrome c (cyt c) release, reactive oxygen species production (ROS), mitochondrial network fragmentation and cell death. This cell death process is regulated, since it correlates with an increase in autophagy but not with plasma membrane permeabilization. The observed increase in Bax c-myc translocation and insertion by PKCα is not due to Bax c-myc phosphorylation, and the higher cell death observed is independent of the PKCα kinase activity. PKCα may therefore have functions other than its kinase activity that aid in Bax c-myc translocation and insertion into mitochondria. Together, these results give a mechanistic insight on apoptosis regulation by PKCα through regulation of Bax insertion into mitochondria.RDS is supported by the FCT grant SFRH/BD/23774/200

Polarisation measurements with a CdTe pixel array detector for Laue hard X-ray focusing telescopes

Polarimetry is an area of high energy astrophysics which is still relatively unexplored, even though it is recognized that this type of measurement could drastically increase our knowledge of the physics and geometry of high energy sources. For this reason, in the context of the design of a Gamma-Ray Imager based on new hard-X and soft gamma ray focusing optics for the next ESA Cosmic Vision call for proposals (Cosmic Vision 2015-2025), it is important that this capability should be implemented in the principal on-board instrumentation. For the particular case of wide band-pass Laue optics we propose a focal plane based on a thick pixelated CdTe detector operating with high efficiency between 60-600 keV. The high segmentation of this type of detector (1-2 mm pixel size) and the good energy resolution (a few keV FWHM at 500 keV) will allow high sensitivity polarisation measurements (a few % for a 10 mCrab source in 106s) to be performed. We have evaluated the modulation Q factors and minimum detectable polarisation through the use of Monte Carlo simulations (based on the GEANT 4 toolkit) for on and off-axis sources with power law emission spectra using the point spread function of a Laue lens in a feasible configuration.Comment: 10 pages, 6 pages. Accepted for publication in Experimental Astronom

A dual-function SNF2 protein drives chromatid resolution and nascent transcripts removal in mitosis

Mitotic chromatin is largely assumed incompatible with transcription due to changes in the transcription machinery and chromosome architecture. However, the mechanisms of mitotic transcriptional inactivation and their interplay with chromosome assembly remain largely unknown. By monitoring ongoing transcription in Drosophila early embryos, we reveal that eviction of nascent mRNAs from mitotic chromatin occurs after substantial chromosome compaction and is not promoted by condensin I. Instead, we show that the timely removal of transcripts from mitotic chromatin is driven by the SNF2 helicase-like protein Lodestar (Lds), identified here as a modulator of sister chromatid cohesion defects. In addition to the eviction of nascent transcripts, we uncover that Lds cooperates with Topoisomerase 2 to ensure efficient sister chromatid resolution and mitotic fidelity. We conclude that the removal of nascent transcripts upon mitotic entry is not a passive consequence of cell cycle progression and/or chromosome compaction but occurs via dedicated mechanisms with functional parallelisms to sister chromatid resolution.info:eu-repo/semantics/publishedVersio

Synbiobacther: engineering "therapeutic" bacteria

Over 1.2 million persons will be diagnosed with breast cancer worldwide per year. Ultrasound treatment is not always successful, as sometimes it just heats the tumour without destroying it. If it would be possible to link this treatment with the expression/release of a therapeutic agent, the joint effect could be more effective. Some efforts have been made in this direction, although to date the results have not been very encouraging; potential reasons include lack of precise control over administration of the drug. Therefore, the purpose of this project is to overcome this barrier through the use of synthetic biology strategies to engineer a model bacterium to trigger release of a therapeutic agent concurrent with ultrasound treatment. The specific plan is to engineer the existing heat shock response machinery from Escherichia coli to trigger the synthesis and release of curcumin in situ. Curcumin has an anti-proliferative capability and an anticarcinogenic and chemopreventive effect. Although curcumin has some attractive properties as a novel drug, it has a poor bioavailability, requiring repetitive oral doses to achieve sufficient concentration inside the cells for therapeutic activity. Hence, the possibility of synthesizing curcumin in situ in a controlled way, as proposed in this project, provides a powerful alternative.info:eu-repo/semantics/publishedVersio

Dopamine neuron activity encodes the length of upcoming contralateral movement sequences

Funding Information: We thank Ana Vaz and Catarina Carvalho for mouse colony management, Thomas Akam and Hélio Rodrigues for help in behavioral box development and implementation, and the Champalimaud Hardware Platform (Filipe Carvalho, Artur Silva, and Dário Bento) for support in the development of the behavioral hardware setup. We thank Cristina Alcácer and Nuno Loureiro for their contributions during the 6-OHDA experiments. This work was supported by Fundação Para a Ciência e Tecnologia (FCT) through a doctoral fellowship ( SFRH/BD/119623/2016 to M.D.M.) and Fundação Luso-Americana para o Desenvolvimento (FLAD) by a visiting student fellowship ( 2018/31 to M.D.M.); by a doctoral fellowship from the Gulbenkian Foundation (to J.A.d.S.), a Marie Curie Fellowship ( MSCA-IF-RI 2016 to L.F.H.), and a Spanish Ministry of Innovation and Sciences doctoral fellowship ( BES-2016-077493 to I.C.); and by ERA-NET , ERC ( COG 617142 ), HHMI ( IEC 55007415 ), National Institutes of Health ( 5U19NS104649 ), and the Simons-Emory International Consortium on Motor Control and the Aligning Science Across Parkinson’s ( ASAP-020551 ) through the Michael J. Fox Foundation for Parkinson’s Research (MJFF) to R.M.C. Further support was obtained from the research infrastructure Congento, co-funded by Lisboa2020 and FCT ( LISBOA-01-0145-FEDER-022170 ). Publisher Copyright: © 2024 The AuthorsDopaminergic neurons (DANs) in the substantia nigra pars compacta (SNc) have been related to movement speed, and loss of these neurons leads to bradykinesia in Parkinson's disease (PD). However, other aspects of movement vigor are also affected in PD; for example, movement sequences are typically shorter. However, the relationship between the activity of DANs and the length of movement sequences is unknown. We imaged activity of SNc DANs in mice trained in a freely moving operant task, which relies on individual forelimb sequences. We uncovered a similar proportion of SNc DANs increasing their activity before either ipsilateral or contralateral sequences. However, the magnitude of this activity was higher for contralateral actions and was related to contralateral but not ipsilateral sequence length. In contrast, the activity of reward-modulated DANs, largely distinct from those modulated by movement, was not lateralized. Finally, unilateral dopamine depletion impaired contralateral, but not ipsilateral, sequence length. These results indicate that movement-initiation DANs encode more than a general motivation signal and invigorate aspects of contralateral movements.publishersversionpublishe

Long-term follow-up of dorsal wedge osteotomy for pediatric freiberg disease

Background: Treatment for Freiberg disease has been largely conservative despite availability of various operative options for severe or refractory cases. The aim of this study was to evaluate the long-term results of pediatric patients with symptomatic Freiberg disease treated with intra-articular dorsal wedge osteotomy. Methods: Pediatric patients treated for Freiberg disease with surgery between January 1982 and 1999 were identified and selected for long-term clinical evaluation. Patients were evaluated regarding operative satisfaction and clinical outcome, performed according to the American Orthopaedic Foot & Ankle Society (AOFAS) lesser toe metatarsophalangeal-interphalangeal scale and range of motion (ROM) of metatarsophalangeal (MTP) joint. Patients had radiographic assessment of degenerative joint status with anteroposterior and oblique foot x-ray. Twenty patients (18 female, 2 male; mean age 15.2 years; range 12-17 years) were identified. The mean follow-up period was 23.4 (range 15-32) years. Results: The clinical outcomes of our patients were classified as excellent in 16 (80%) and good in 4 (20%). The AOFAS mean score was 96.8 (range 91-100) points at the last clinical appointment. A negative correlation between AOFAS score and time of follow-up (r's = -0.61, P < .001) was found. Also, a strong negative correlation was found between Smillie classification and AOFAS final score (r's = -0.88, P < .001). Conclusion: The patients were very satisfied with pain and quality of life at a mean follow-up time of 23.4 years. To our knowledge, this is the first long-term follow-up report supporting the procedure described by Gauthier and Elbaz as a good option for operative treatment of Freiberg disease.info:eu-repo/semantics/publishedVersio