A 17-residue sequence from the matrix metalloproteinase-9 (MMP-9) hemopexin domain binds α4β1 integrin and inhibits MMP-9-induced functions in chronic lymphocytic leukemia B cells

13 páginas, 7 figuras, 2 tablas -- PAGS nros. 27601-27613We previously showed that pro-matrix metalloproteinase-9 (proMMP-9) binds to B chronic lymphocytic leukemia (B-CLL) cells and contributes to B-CLL progression by regulating cell migration and survival. Induction of cell survival involves a non-proteolytic mechanism and the proMMP-9 hemopexin domain (PEX9). To help design specific inhibitors of proMMP-9-cell binding, we have now characterized B-CLL cell interaction with the isolated PEX9. B-CLL cells bound soluble and immobilized GST-PEX9, but not GST, and binding was mediated by α4β1 integrin. The ability to recognize PEX9 was observed in all 20 primary samples studied irrespective of their clinical stage or prognostic marker phenotype. By preparing truncated forms of GST-PEX9 containing structural blades B1B2 or B3B4, we have identified B3B4 as the primary α4β1 integrin-interacting region within PEX9. Overlapping synthetic peptides spanning B3B4 were then tested in functional assays. Peptide P3 (FPGVPLDTHDVFQYREKAYFC), a sequence present in B4 or smaller versions of this sequence (peptides P3a/P3b), inhibited B-CLL cell adhesion to GST-PEX9 or proMMP-9, with IC50 values of 138 and 279 μm, respectively. Mutating the two aspartate residues to alanine rendered the peptides inactive. An anti-P3 antibody also inhibited adhesion to GST-PEX9 and proMMP-9. GST-PEX9, GST-B3B4, and P3/P3a/P3b peptides inhibited B-CLL cell transendothelial migration, whereas the mutated peptide did not. B-CLL cell incubation with GST-PEX9 induced intracellular survival signals, namely Lyn phosphorylation and Mcl-1 up-regulation, and this was also prevented by the P3 peptides. The P3 sequence may, therefore, constitute an excellent target to prevent proMMP-9 contribution to B-CLL pathogenesisThis work was supported by Grants SAF2009–07035 and RTICC RD06/0020/0011 (to A. G.-P.) and RTICC RD06/0020/0080 (to M. J. T.) from the Ministerio de Ciencia e Innovación, Spain, and by a grant from the Fundación Puerta de Hierro (to J. A. G. M.)Peer reviewe

Healthcare workers hospitalized due to COVID-19 have no higher risk of death than general population. Data from the Spanish SEMI-COVID-19 Registry

Aim To determine whether healthcare workers (HCW) hospitalized in Spain due to COVID-19 have a worse prognosis than non-healthcare workers (NHCW). Methods Observational cohort study based on the SEMI-COVID-19 Registry, a nationwide registry that collects sociodemographic, clinical, laboratory, and treatment data on patients hospitalised with COVID-19 in Spain. Patients aged 20-65 years were selected. A multivariate logistic regression model was performed to identify factors associated with mortality. Results As of 22 May 2020, 4393 patients were included, of whom 419 (9.5%) were HCW. Median (interquartile range) age of HCW was 52 (15) years and 62.4% were women. Prevalence of comorbidities and severe radiological findings upon admission were less frequent in HCW. There were no difference in need of respiratory support and admission to intensive care unit, but occurrence of sepsis and in-hospital mortality was lower in HCW (1.7% vs. 3.9%; p = 0.024 and 0.7% vs. 4.8%; p<0.001 respectively). Age, male sex and comorbidity, were independently associated with higher in-hospital mortality and healthcare working with lower mortality (OR 0.211, 95%CI 0.067-0.667, p = 0.008). 30-days survival was higher in HCW (0.968 vs. 0.851 p<0.001). Conclusions Hospitalized COVID-19 HCW had fewer comorbidities and a better prognosis than NHCW. Our results suggest that professional exposure to COVID-19 in HCW does not carry more clinical severity nor mortality

Investigación joven con perspectiva de género II

Actas del II Congreso de jóvenes investigadorxs con perspectiva de género (Getafe, 26 y 27 de junio de 2017) organizado por el Instituto Universitario de Estudios de Género de la Universidad Carlos III de Madrid

Papel de microambiente en la respuesta de células de leucemia linfocítica crónica a trióxido de arsénico: mecanismos de resistencia

La leucemia linfocítica crónica, LLC, se caracteriza por acumulación en sangre periférica de linfocitos B aberrantes CD5 positivos, en adelante células LLC. La enfermedad progresa cuando estas células infiltran órganos linfoides, donde reciben señales de supervivencia que dificultan la terapia. A pesar de los avances, la LLC continúa siendo una enfermedad incurable, siendo necesario desarrollar nuevas estrategias terapéuticas sobre la base de la contribución del microambiente a la patogénesis de la enfermedad. El trióxido de arsénico, en lo sucesivo ATO, induce eficientemente apoptosis en todos los casos de LLC, presentándose como una potencial terapia. El perfil de expresión génica inducido por ATO en células LLC es consistente con una respuesta antioxidante y defensiva. De hecho, ATO induce la expresión de genes como los codificantes de HMOX1 y MMP9, con funciones en la regulación del estrés oxidativo y la supervivencia de las células LLC, respectivamente. HMOX1 parece favorecer el efecto del ATO y, por tanto, media señales proapoptóticas, mientras que MMP9 promueve la supervivencia celular por un mecanismo que implica la modulación del balance entre los miembros pro y antiapoptóticos de la familia BCL2. El cocultivo con estroma de médula ósea, en adelante BMS, también protege a las células LLC de la apoptosis inducida por ATO, y esta protección es revertida por el bloqueo de MMP9 o de las integrinas alfa4beta1 o alfaLbeta2, indicando que tanto factores solubles como interacciones directas célula-célula están implicados en la misma. Además, el cocultivo con BMS induce activación en las células LLC de AKT dependiente de PI3Kdelta y PKCbeta. Esto conduce, a su vez, a la activación de los factores de transcripción NFkappaB y STAT3 que, finalmente, median un incremento en la expresión de la proteína antiapoptótica MCL1. Esta inducción de MCL1 en las células LLC por el mecanismo anterior es esencial en la resistencia a ATO inducida por estroma. De hecho, el bloqueo de PI3Kdelta y PKCbeta o la disminución de los niveles de MCL1 revierten esta protección. Considerados conjuntamente, estos resultados sugieren que la combinación de ATO con inhibidores específicos de MMP9, PI3Kdelta y,o PKCbeta podría constituir una eficiente terapia alternativa o complementaria para la LLC