Faculdade de Medicina
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- Resistance to tyrosine kinase inhibitors in chronic myeloid leukemia — from molecular mechanisms to clinical relevancePublication . Alves, Raquel; Gonçalves, Ana Cristina; Rutella, Sergio; Almeida, António M.; Rivas, Javier De Las; Trougakos, Ioannis P.; Ribeiro, Ana Bela SarmentoResistance to targeted therapies is a complex and multifactorial process that culminates in the selection of a cancer clone with the ability to evade treatment. Chronic myeloid leukemia (CML) was the first malignancy recognized to be associated with a genetic alteration, the t(9;22)(q34;q11). This translocation originates the BCR-ABL1 fusion gene, encoding the cytoplasmic chimeric BCR-ABL1 protein that displays an abnormally high tyrosine kinase activity. Although the vast majority of patients with CML respond to Imatinib, a tyrosine kinase inhibitor (TKI), resistance might occur either de novo or during treatment. In CML, the TKI resistance mechanisms are usually subdivided into BCR-ABL1-dependent and independent mechanisms. Furthermore, patients’ compliance/adherence to therapy is critical to CML management. Techniques with enhanced sensitivity like NGS and dPCR, the use of artificial intelligence (AI) techniques, and the development of mathematical modeling and computational prediction methods could reveal the underlying mechanisms of drug resistance and facilitate the design of more effective treatment strategies for improving drug efficacy in CML patients. Here we review the molecular mechanisms and other factors involved in resistance to TKIs in CML and the new methodologies to access these mechanisms, and the therapeutic approaches to circumvent TKI resistance.
- A rapid real-time polymerase chain reaction-based live virus microneutralization assay for detection of neutralizing antibodies against SARS-CoV-2 in blood/serumPublication . Abidi, Syed Hani; Imtiaz, Kehkashan; Kanji, Akbar; Qaiser, Shama; Khan, Erum; Iqbal, Kiran; Veldhoen, Marc; Ghias, Kulsoom; Simas, J. Pedro; Hasan, ZahraBackground Individuals recovering from COVID-19 are known to have antibodies against the Spike and other structural proteins. Antibodies against Spike have been shown to display viral neutralization. However, not all antibodies against Spike have neutralizing ability although they may be cross-reactive. There is a need for easy-to-use SARS-CoV-2 neutralizing assays for the determination of virus-neutralizing activity in sera of individuals. Here we describe a PCR-based micro-neutralization assay that can be used to evaluate the viral neutralization titers of serum from SARS-CoV-2 infected individuals. Methods The SARS-CoV-2 strain used was isolated from a nasopharyngeal specimen of a COVID-19 case. The limiting dilution method was used to obtain a 50% tissue culture infective dose (TCID50) of Vero cells. For the micro-neutralization assay, 19 serum samples, with positive IgG titers against Spike Receptor-Binding Domain (RBD) were tested. After 24 hours, infected cells were inspected for the presence of a cytopathic effect, lysed and RNA RT-PCR conducted for SARS-CoV-2. PCR target Ct values were used to calculate percent neutralization/inhibition of SARS-CoV-2. Results Out of 19 samples, 13 samples gave 100% neutralization at all dilutions, 1 sample showed neutralization at the first dilution, 4 samples showed neutralization at lower dilutions, while one sample did not demonstrate any neutralization. The RBD ODs and neutralization potential percentages were found to be positively correlated. Conclusion We describe a rapid RT-PCR-based SARS-CoV-2 microneutralization assay for the detection of neutralizing antibodies. This can effectively be used to test the antiviral activity of serum antibodies for the investigation of both disease-driven and vaccine-induced responses.
- MLL1 is regulated by KSHV LANA and is important for virus latencyPublication . Tan, Min; Li, Shijun; Juillard, Franceline; Chitas, Rute; Custódio, Tânia F.; Xue, Han; Szymula, Agnieszka; Sun, Qiming; Liu, Bing; Álvarez, Ángel L.; Chen, She; Simas, J. Pedro; McVey, Colin E.; Kaye, Kenneth M.Mixed lineage leukemia 1 (MLL1) is a histone methyltransferase. Kaposi's sarcoma-associated herpesvirus (KSHV) is a leading cause of malignancy in AIDS. KSHV latently infects tumor cells and its genome is decorated with epigenetic marks. Here, we show that KSHV latency-associated nuclear antigen (LANA) recruits MLL1 to viral DNA where it establishes H3K4me3 modifications at the extensive KSHV terminal repeat elements during primary infection. LANA interacts with MLL1 complex members, including WDR5, integrates into the MLL1 complex, and regulates MLL1 activity. We describe the 1.5-A crystal structure of N-terminal LANA peptide complexed with MLL1 complex member WDR5, which reveals a potential regulatory mechanism. Disruption of MLL1 expression rendered KSHV latency establishment highly deficient. This deficiency was rescued by MLL1 but not by catalytically inactive MLL1. Therefore, MLL1 is LANA regulable and exerts a central role in virus infection. These results suggest broad potential for MLL1 regulation, including by non-host factors.
- Moringa as a household water purification method – community perception and pilot study in Guinea-BissauPublication . Bancessi, Aducabe; Teodósio, Rosa; Duarte, Elizabeth; Baldé, Aladje; Catarino, Luís; Nazareth, TeresaBackground: Public perceptions of water-related issues are still under-researched topics. The current paper intends to explore a local community’s perceptions regarding household water purification (HWP) strategies, namely before and after trying a new method: moringa seeds powder (moringa-teabag). Methods: In September 2020, six focus group discussions (N = 65) assessing perceptions about the usefulness of Moringa oleifera Lam (Moringaceae) as a HWP method (before moringa-based HWP trials), and questionnaires (N = 104) evaluating successes and identifying difficulties (after one week of moringa-based HWP trials). Participants were all women aged over 18 years, living in Ondame, Biombo region, Guinea-Bissau. Data were analyzed using qualitative and quantitative approaches. Results: The focus group discussions revealed that people are aware of the fact that water can transmit diseases. Although certain persons showed concern about shallow well water safety, people generally underestimate the risk, as they trust tubewell water. Not everyone had an understanding of what water contamination is, or the concept of medical importance. Some respondents declared they use traditional methods such as boiling and bleach to treat water before drinking. However, those who reported no kind of treatment indicated reasons such as lack of time, cost, and bleach’s taste and smell. In the questionnaire, more than half of the participants (68%) reported treating water before consumption. Nevertheless, these results are not consistent with our field notes. Participants demonstrated a strong belief in the capacity of moringa-teabags to purify water and even consider them better or much better (81%) than other methods. Participants asked for more information on moringa-teabag for household water purification. Conclusion: More information on water treatment and water safety would help to raise public awareness about waterborne diseases. These findings could be used to promote greater adherence to moringa-based HWP as an alternative to household water treatment.
- An SNF2 helicase-like protein links mitotic transcription termination to sister chromatid resolutionPublication . Carmo, Catarina; Coelho, João; Silva, Rui; Tavares, Alexandra; Boavida, Ana; Gaetani, Paola; Martinho, Rui Gonçalo; Oliveira, Raquel A.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 transcriptional termination, we uncovered that Lds cooperates with Topoisomerase 2 to ensure efficient sister chromatid resolution and mitotic fidelity. We conclude that mitotic transcriptional termination 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.
- Mechanisms leading to gut dysbiosis in COVID-19: current evidence and uncertainties based on adverse outcome pathwaysPublication . Clerbaux, Laure Alix; Fillipovska, Julija; Muñoz, Amalia; Petrillo, Mauro; Coecke, Sandra; Amorim, Maria João; Grenga, LuciaAlteration in gut microbiota has been associated with COVID-19. However, the underlying mechanisms remain poorly understood. Here, we outlined three potential interconnected mechanistic pathways leading to gut dysbiosis as an adverse outcome following SARS-CoV-2 presence in the gastrointestinal tract. Evidence from the literature and current uncertainties are reported for each step of the different pathways. One pathway investigates evidence that intestinal infection by SARS-CoV-2 inducing intestinal inflammation alters the gut microbiota. Another pathway links the binding of viral S protein to angiotensin-converting enzyme 2 (ACE2) to the dysregulation of this receptor, essential in intestinal homeostasis—notably for amino acid metabolism—leading to gut dysbiosis. Additionally, SARS-CoV-2 could induce gut dysbiosis by infecting intestinal bacteria. Assessing current evidence within the Adverse Outcome Pathway framework justifies confidence in the proposed mechanisms to support disease management and permits the identification of inconsistencies and knowledge gaps to orient further research.
- Temporal order of clinical and biomarker changes in familial frontotemporal dementiaPublication . Frontotemporal Dementia Prevention Initiative (FPI) Investigators; ALLFTD Investigators; GENFI investigators; Staffaroni, Adam M.; Quintana, Melanie; Wendelberger, Barbara; Heuer, Hilary W.; Russell, Lucy L.; Cobigo, Yann; Wolf, Amy; Goh, Sheng Yang Matt; Petrucelli, Leonard; Gendron, Tania F.; Heller, Carolin; Clark, Annie L.; Taylor, Jack Carson; Wise, Amy; Ong, Elise; Forsberg, Leah; Brushaber, Danielle; Rojas, Julio C.; VandeVrede, Lawren; Ljubenkov, Peter; Kramer, Joel; Casaletto, Kaitlin B.; Appleby, Brian; Bordelon, Yvette; Botha, Hugo; Dickerson, Bradford C.; Domoto-Reilly, Kimiko; Fields, Julie A.; Foroud, Tatiana; Gavrilova, Ralitza; Geschwind, Daniel; Ghoshal, Nupur; Goldman, Jill; Graff-Radford, Jonathon; Graff-Radford, Neill; Grossman, Murray; Hall, Matthew G.H.; Hsiung, Ging Yuek; Huey, Edward D.; Irwin, David; Jones, David T.; Kantarci, Kejal; Kaufer, Daniel; Knopman, David; Kremers, Walter; Lago, Argentina Lario; Lapid, Maria I.; Maruta, Carolina; Simões do Couto, Frederico; Almeida, Maria RosarioUnlike familial Alzheimer’s disease, we have been unable to accurately predict symptom onset in presymptomatic familial frontotemporal dementia (f-FTD) mutation carriers, which is a major hurdle to designing disease prevention trials. We developed multimodal models for f-FTD disease progression and estimated clinical trial sample sizes in C9orf72, GRN and MAPT mutation carriers. Models included longitudinal clinical and neuropsychological scores, regional brain volumes and plasma neurofilament light chain (NfL) in 796 carriers and 412 noncarrier controls. We found that the temporal ordering of clinical and biomarker progression differed by genotype. In prevention-trial simulations using model-based patient selection, atrophy and NfL were the best endpoints, whereas clinical measures were potential endpoints in early symptomatic trials. f-FTD prevention trials are feasible but will likely require global recruitment efforts. These disease progression models will facilitate the planning of f-FTD clinical trials, including the selection of optimal endpoints and enrollment criteria to maximize power to detect treatment effects.
- Gut as an alternative entry route for SARS-CoV-2: current evidence and uncertainties of productive enteric infection in COVID-19Publication . Clerbaux, Laure Alix; Mayasich, Sally A.; Munoz Pineiro, Amalia; Soares, Helena; Petrillo, Mauro; Albertini, Maria Cristina; Lanthier, Nicolas; Grenga, Lucia; Amorim, Maria JoãoThe gut has been proposed as a potential alternative entry route for SARS-CoV-2. This was mainly based on the high levels of SARS-CoV-2 receptor expressed in the gastrointestinal (GI) tract, the observations of GI disorders (such as diarrhea) in some COVID-19 patients and the detection of SARS-CoV-2 RNA in feces. However, the underlying mechanisms remain poorly understood. It has been proposed that SARS-CoV-2 can productively infect enterocytes, damaging the intestinal barrier and contributing to inflammatory response, which might lead to GI manifestations, including diarrhea. Here, we report a methodological approach to assess the evidence supporting the sequence of events driving SARS-CoV-2 enteric infection up to gut adverse outcomes. Exploring evidence permits to highlight knowledge gaps and current inconsistencies in the literature and to guide further research. Based on the current insights on SARS-CoV-2 intestinal infection and transmission, we then discuss the potential implication on clinical practice, including on long COVID. A better understanding of the GI implication in COVID-19 is still needed to improve disease management and could help identify innovative therapies or preventive actions targeting the GI tract.
- Competition for endothelial cell polarity drives vascular morphogenesis in the mouse retinaPublication . Barbacena, Pedro; Dominguez-Cejudo, Maria; Fonseca, Catarina G.; Gómez-González, Manuel; Faure, Laura M.; Zarkada, Georgia; Pena, Andreia; Pezzarossa, Anna; Ramalho, Daniela; Giarratano, Ylenia; Ouarné, Marie; Barata, David; Fortunato, Isabela C.; Misikova, Lenka Henao; Mauldin, Ian; Carvalho, Yulia; Trepat, Xavier; Roca-Cusachs, Pere; Eichmann, Anne; Bernabeu, Miguel O.; Franco, Cláudio A.Blood-vessel formation generates unique vascular patterns in each individual. The principles governing the apparent stochasticity of this process remain to be elucidated. Using mathematical methods, we find that the transition between two fundamental vascular morphogenetic programs—sprouting angiogenesis and vascular remodeling—is established by a shift of collective front-to-rear polarity of endothelial cells in the mouse retina. We demonstrate that the competition between biochemical (VEGFA) and mechanical (blood-flow-induced shear stress) cues controls this collective polarity shift. Shear stress increases tension at focal adhesions overriding VEGFA-driven collective polarization, which relies on tension at adherens junctions. We propose that vascular morphogenetic cues compete to regulate individual cell polarity and migration through tension shifts that translates into tissue-level emergent behaviors, ultimately leading to uniquely organized vascular patterns.