Cellular characterization of hematopoietic system and hematopoietic niches in murine model of sickle cell anemia

O sistema hematopoético é o responsável pela produção das células sanguíneas do organismo em homeostase ou estresse. Seu funcionamento depende da manutenção e diferenciação coordenada das células-tronco hematopoiéticas (HSC) que está intimamente associada ao nicho hematopoético. O nicho hematopoético é um microambiente altamente dinâmico, orquestrado e heterogêneo quanto à sua composição celular. Dentre os tipos celulares que o compõem estão as células endoteliais e células estromais mesenquimais multipotentes (MSC) que junto aos demais componentes suportam e regulam a autorrenovação e diferenciação das HSC. Entretanto, doenças hematológicas podem alterar o sistema hematopoético, as HSC e demais células do microambiente. Por isso, este estudo analisou a hematopoese, os nichos hematopoéticos intramedular e extramedular esplênico e as MSC da medula óssea (MO) de camundongos falciformes (Townes-SS) com diferentes idades e após o tratamento com hidroxiuréia (HU). Os resultados revelaram maior número de progenitores de eritrócitos e megacariócitos (MEP) no nicho intramedular dos Townes-SS, além do maior número de: HSC, progenitores mieloides comuns (CMP), progenitores de granulócitos e monócitos (GMP) e MEP no nicho extramedular esplênico. Esses achados demonstram que a análise combinada da hematopoese intramedular e extramedular esplênica dos Townes-SS concorda com dados já descritos para MO de humanos. O aumento dos MEP foi acompanhado de aumento na frequência de progenitores eritroides terminais totais e de alteração no perfil mitótico da diferenciação eritroide terminal murina em ambos os nichos. A análise das células não hematopoéticas revelou maior número de células-tronco endoteliais, MSC e células estromais não mesenquimais no nicho extramedular esplênico. As MSC da MO isoladas e cultivadas in vitro apresentaram um perfil transcricional relacionado com aumento da diferenciação das HSC em detrimento da manutenção da quiescência. Por fim, o tratamento dos Townes-SS com HU resultou em menor número de HSC, CMP, GMP e MEP nos nichos hematopoéticos intramedular e extramedular esplênico dos animais tratados frente aos animais não tratados de mesmo genótipo e idade. Este comportamento celular concorda novamente com dados já descritos em humanos que fazem uso de HU frente àqueles que não a utilizam. Portanto, os resultados obtidos demonstram que os Townes-SS podem ser utilizados como modelo animal em estudos pré-clínicos ou de ciência básica que avaliem os impactos da AF ou o efeito de tratamentos sobre as HSC, demais células hematopoéticas e células não hematopoéticas dos nichos hematopoéticos.The hematopoietic system is responsible for the production of blood cells in the body in homeostasis or stress. Its functioning depends on the maintenance and coordinated differentiation of hematopoietic stem cells (HSC), which are closely associated with the hematopoietic niche. The hematopoietic niche is a highly dynamic microenvironment, orchestrated and heterogeneous in terms of its cellular composition. Among the cell types that make up the niche are the endothelial cells and multipotent mesenchymal stromal cells (MSC) that together with the other components support and regulate the self-renewal and differentiation of HSC. However, hematological diseases can alter the hematopoietic system, the HSC and other cells in the microenvironment Therefore, this study analyzed the hematopoiesis, intramedullary and extramedullary splenic hematopoietic niches and bone marrow (BM) MSCs of sickle-cell mice (Townes-SS) at different ages and after treatment with Hydroxyurea (HU). The results revealed a greater number of erythrocyte-megakaryocyte progenitor megakaryocytic-erythroid progenitors (MEP) in the intramedullary niche of the Townes-SS, in addition to a greater number of: HSC, common myeloid progenitors (CMP), granulocyte-monocyte progenitors (GMP) and MEP in the extramedullary niche splenic. These findings demonstrate that the combined analysis of intra and extramedullary splenic hematopoiesis of the Townes-SS agrees with data already described for OM in humans. The increase in MEP was accompanied by an increase in the frequency of total terminal erythroid progenitors and an alteration in the mitotic profile of the murine terminal erythroid differentiation in both niches. The analysis of non-hematopoietic cells revealed a greater number of endothelial stem cells, MSC and non-mesenchymal stromal cells in the splenic extramedullary niche. The analysis of isolated and in vitro cultivated OM MSCs did not show morphofunctional differences, except for a transcriptional profile related to increased HSC differentiation at the expense of quiescence maintenance. Finally, the treatment of Townes-SS with HU resulted in a lower number of HSC, CMP, GMP and MEP in the intramedullary and extramedullary splenic hematopoietic niches of treated animals compared to untreated ones. This cellular behavior agrees again with data already described in humans who use HU compared to those who do not use it. Therefore, the results obtained demonstrate that the Townes-SS can be used as an animal model for preclinical or basic science studies that assess the impacts of FA on HSC and other hematopoietic or non-hematopoietic cells of hematopoietic niches, as well as in tests on the effect of drugs and drugs on hematopoiesis, hematopoietic niche and specific cells in the context of FA

Systematic Review of Available CAR-T Cell Trials around the World

In this systematic review, we foresee what could be the approved scenario in the next few years for CAR-T cell therapies directed against hematological and solid tumor malignancies. China and the USA are the leading regions in numbers of clinical studies involving CAR-T. Hematological antigens CD19 and BCMA are the most targeted, followed by mesothelin, GPC3, CEA, MUC1, HER2, and EGFR for solid tumors. Most CAR constructs are second-generation, although third and fourth generations are being largely explored. Moreover, the benefit of combining CAR-T treatment with immune checkpoint inhibitors and other drugs is also being assessed. Data regarding product formulation and administration, such as cell phenotype, transfection technique, and cell dosage, are scarce and could not be retrieved. Better tracking of trials’ status and results on the ClinicalTrials.gov database should aid in a more concise and general view of the ongoing clinical trials involving CAR-T cell therapy

Dynamics of SARS-CoV-2 Variants of Concern in Vaccination Model City in the State of Sao Paulo, Brazil

From a country with one of the highest SARS-CoV-2 morbidity and mortality rates, Brazil has implemented one of the most successful vaccination programs. Brazil’s first model city vaccination program was performed by the CoronaVac vaccine (Sinovac Biotech) in the town of Serrana, São Paulo State. To evaluate the vaccination effect on the SARS-CoV-2 molecular dynamics and clinical outcomes, we performed SARS-CoV-2 molecular surveillance on 4375 complete genomes obtained between June 2020 and April 2022 in this location. This study included the period between the initial SARS-CoV-2 introduction and during the vaccination process. We observed that the SARS-CoV-2 substitution dynamics in Serrana followed the viral molecular epidemiology in Brazil, including the initial identification of the ancestral lineages (B.1.1.28 and B.1.1.33) and epidemic waves of variants of concern (VOC) including the Gamma, Delta, and, more recently, Omicron. Most probably, as a result of the immunization campaign, the mortality during the Gamma and Delta VOC was significantly reduced compared to the rest of Brazil, which was also related to lower morbidity. Our phylogenetic analysis revealed the evolutionary history of the SARS-CoV-2 in this location and showed that multiple introduction events have occurred over time. The evaluation of the COVID-19 clinical outcome revealed that most cases were mild (88.9%, 98.1%, 99.1% to Gamma, Delta, and Omicron, respectively) regardless of the infecting VOC. In conclusion, we observed that vaccination was responsible for reducing the death toll rate and related COVID-19 morbidity, especially during the gamma and Delta VOC; however, it does not prevent the rapid substitution rate and morbidity of the Omicron VOC