RESUMO
PROBLEM: Human papillomavirus infection is integral to developing invasive cervical cancer in the majority of patients. In a recent genome-wide association study, rs9357152 and rs4243652 have been associated with seropositivity for HPV16 or HPV18, respectively. It is unknown whether these variants also associate with cervical cancer triggered by either HPV16 or HPV18. METHODS: We investigate whether the two HPV susceptibility variants show association with type-specific cervical cancer in a genetic case-control study with cases stratified by HPV16 or HPV18, respectively. We further tested whether rs9357152 modulates gene expression of any of 36 genes at the human leukocyte antigen locus in 256 cervical tissues. RESULTS: rs9357152 was associated with invasive HPV16-positive cervical cancer (OR 1.33, 95%CI 1.03-1.70, p = 0.03), and rs4243652 was associated with HPV18-positive adenocarcinomas (OR 2.96, 95%CI 1.18-7.41, p = 0.02). These associations remained borderline significant after testing against different sets of controls. rs9357152 was found to be an eQTL for HLA-DRB1 in HPV-positive cervical tissues (pANOVA = 0.0009), with the risk allele lowering mRNA levels. CONCLUSIONS: We find evidence that HPV seropositivity variants at chromosome 6 and 14 may modulate type-specific cervical cancer risk. rs9357152 may exert its effect through regulating HLA-DRB1 induction in the presence of HPV. In regard of multiple testing, these results need to be confirmed in larger studies.
Assuntos
Infecções por Papillomavirus , Neoplasias do Colo do Útero , Feminino , Humanos , Neoplasias do Colo do Útero/genética , Cadeias HLA-DRB1/genética , Infecções por Papillomavirus/complicações , Estudos de Casos e Controles , Estudo de Associação Genômica Ampla , Papillomavirus Humano 16/genética , Papillomavirus Humano 18/genética , GenômicaRESUMO
The number of wars in the world is on the rise. A number of studies have documented the devastating impact on the public and especially public mental health. Health care systems in low- and lower-middle income countries that are frequently already challenged by the existing mental health services gap cannot provide the necessary care for those displaced by war with existing services. This is especially the case in the Kurdistan Region of Iraq (KRI) after the invasion of the terror organization ISIS in 2014. Most projects in post-conflict areas focus on short term basic psychological services and do not contribute to sustainable long-term capacity building of mental health services. An "Institute for Psychotherapy and Psychotraumatology" was therefore founded in order to train local specialists on a professional level with evidence-based methods adapted to culture and create sustainable long-term structures for psychotherapeutic treatment in the KRI. To achieve this, a number of measures were implemented, including the creation of a "Master of Advanced Studies of Psychotherapy and Psychotraumatology" in collaboration with local communities and the regional University. Two cohorts of students have successfully finished the master's program and a third cohort are expected to graduate in 2023. Improving the capacity of local health care services to provide low-barrier, professional psychotherapeutic care in post-conflict regions supported by the innovative model presented in this article can be expected to improve the burden of psychological problems and contribute to peacebuilding.
RESUMO
The diagnosis of Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS), a rare variant of female sexual development, is usually made during puberty. The uncertainty in self-image and the impos-sibility of becoming pregnant often lead to considerable stress. Although psychosomatic support is consistently recommended in the literature, there have been only a few studies on the psychological aspects of MRKHS. The aim of the present study is to investigate the quality of life or distress of women with MRKHS undergoing neovaginal surgery and, on the other hand, to evaluate effects of the intervention for support during treatment. Methods In an explorative quasi-experimental pre-post study at a national centre for neovaginal surgery, all patients were offered a psychosomatic intervention (intervention group IG, n=23) and their sexual function (FSFI), psychological distress (PHQ-D) and health-related quality of life (SF-12) were assessed before surgery (t0) and six months after (t1). These were compared with data from a sample collected before and after the intervention period (comparison group VG, n=30). Results While the physical quality of life (SF-12) of both groups was unremarkable at both time points, there was a significant impairment in the psychological quality of life. Both groups (IG, VG) improved from t0 to t1 in their sexual function (FSFI) and showed lower depression scores (PHQ-D). The specific intervention developed was well accepted by those affected and rated as helpful. However, this subjectively perceived effectiveness of the intervention was not reflected by improvement on the quality of life scale (SF-12) and depression scale (PHQ-D). Conclusion Those affected show a clear, clinically relevant distress (SF-12), but this is not reflected in the form of psychological comorbidity (PHQ-D). This apparent discrepancy points to psychologically stable women with acute distress due to the diagnosis of variant sex de-evolution. For them, a low-threshold support service with a supportive character seems to be necessary and helpful during the surgical treatment. The reconstructive therapy for the creation of a neovagina seems to have a positive influence on the psychological quality of life. The fact that pregnancy is still not possible due to the missing uterus could be a reason for not reaching the quality of life of the average population.
Assuntos
Transtornos 46, XX do Desenvolvimento Sexual , Anormalidades Congênitas , Feminino , Humanos , Qualidade de Vida , Vagina/cirurgia , Transtornos 46, XX do Desenvolvimento Sexual/psicologia , Transtornos 46, XX do Desenvolvimento Sexual/cirurgia , Ductos Paramesonéfricos/cirurgia , Anormalidades Congênitas/cirurgia , Anormalidades Congênitas/psicologiaRESUMO
(1) Background: Equine arteritis virus (EAV) infection causes reproductive losses and systemic vasculitis in susceptible equidae. The intact male becomes the virus' reservoir upon EAV infection, as it causes a chronic-persistent infection of the accessory sex glands. Infected semen is the main source of virus transmission. (2) Here, we describe acute EAV infection and spread in a stallion population after introduction of new members to the group. (3) Conclusions: acute clinical signs, acute phase detection of antigen via (PCR) nasal swabs or (EDTA) blood, and seroconversion support the idea of transmission via seminal fluids into the respiratory tract(s) of others. This outbreak highlights EAV's horizontal transmission via the respiratory tract. This route should be considered in a chronic-persistently infected herd, when seronegative animals are added to the group.
Assuntos
Infecções por Arterivirus/epidemiologia , Infecções por Arterivirus/veterinária , Surtos de Doenças , Equartevirus , Doenças dos Cavalos/epidemiologia , Animais , Infecções por Arterivirus/transmissão , Infecções por Arterivirus/virologia , Transmissão de Doença Infecciosa , Doenças dos Cavalos/virologia , Cavalos , Masculino , Masturbação , Infecção Persistente , Sistema Respiratório/virologia , Sêmen/virologiaRESUMO
Clinical development of chimeric antigen receptor (CAR)-T-cell therapy has been enabled by advances in synthetic biology, genetic engineering, clinical-grade manufacturing, and complex logistics to distribute the drug product to treatment sites. A key ambition of the CARAMBA project is to provide clinical proof-of-concept for virus-free CAR gene transfer using advanced Sleeping Beauty (SB) transposon technology. SB transposition in CAR-T engineering is attractive due to the high rate of stable CAR gene transfer enabled by optimized hyperactive SB100X transposase and transposon combinations, encoded by mRNA and minicircle DNA, respectively, as preferred vector embodiments. This approach bears the potential to facilitate and expedite vector procurement, CAR-T manufacturing and distribution, and the promise to provide a safe, effective, and economically sustainable treatment. As an exemplary and novel target for SB-based CAR-T cells, the CARAMBA consortium has selected the SLAMF7 antigen in multiple myeloma. SLAMF7 CAR-T cells confer potent and consistent anti-myeloma activity in preclinical assays in vitro and in vivo. The CARAMBA clinical trial (Phase-I/IIA; EudraCT: 2019-001264-30) investigates the feasibility, safety, and anti-myeloma efficacy of autologous SLAMF7 CAR-T cells. CARAMBA is the first clinical trial with virus-free CAR-T cells in Europe, and the first clinical trial that uses advanced SB technology worldwide.
Assuntos
Mieloma Múltiplo , Terapia Genética , Humanos , Imunoterapia Adotiva , Mieloma Múltiplo/terapia , Família de Moléculas de Sinalização da Ativação Linfocitária , Linfócitos TAssuntos
Imunoterapia Adotiva/métodos , Leucemia Mieloide Aguda/terapia , Mieloma Múltiplo/terapia , Receptores de Antígenos Quiméricos/uso terapêutico , Linfócitos T/fisiologia , Técnicas de Transferência de Genes , Humanos , Leucemia Mieloide Aguda/imunologia , Terapia de Alvo Molecular/métodos , Terapia de Alvo Molecular/tendências , Mieloma Múltiplo/imunologia , Terapia Viral Oncolítica/efeitos adversos , Vírus Oncolíticos/fisiologia , Receptores de Antígenos de Linfócitos T/fisiologia , Receptores de Antígenos de Linfócitos T/uso terapêutico , Receptores de Antígenos Quiméricos/metabolismo , Família de Moléculas de Sinalização da Ativação Linfocitária/antagonistas & inibidores , Família de Moléculas de Sinalização da Ativação Linfocitária/imunologia , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Tirosina Quinase 3 Semelhante a fms/imunologiaRESUMO
HbA1c is the most accepted laboratory parameter for the long term observation of glucose control. There is still much of a debate about the use of HbA1c as a metabolic indicator in diabetic patients (DM) on haemodialysis (HD) and erythropoiesis-stimulating agent (ESA) therapy because of the altered erythrocyte turn over in patients with chronic kidney disease and haemodialysis (CKD5D). In 102 CKD5 patients with and without diabetes mellitus, we examined the dose dependent variability in HbA1c and fructosamine levels under haemodialysis and treated with epoetin α (n=48) and a new generation agent with continuous stimulation of methoxy polyethylene glycol epoetin beta (C.E.R.A.; n=54). HbA1c levels were affected by therapy with ESA treatments. ESA dose was inversely correlated with HbA1c and an escalation of 10.000 IU per week induced an estimated decrease of HbA1c of 0.6 percent. In addition, the increase of reticulocyte number as a marker for erythropoiesis was significantly inversely correlated with the increase of ΔHbA1c. ESA treatments had no such effect on the alternative metabolic parameter fructosamine. When compared, both therapeutic agents had comparable success in attaining haemoglobin (Hb) target values. C.E.R.A. showed better correlation and was more effective over a longer dose interval. Our results show that HbA1c levels in patients should be carefully interpreted based on interfering factors. Nevertheless, HbA1c is currently the most consistent parameter for use ascertaining metabolic status of patients suffering from diabetes mellitus.
Assuntos
Nefropatias Diabéticas , Epoetina alfa/administração & dosagem , Eritropoetina/administração & dosagem , Frutosamina/sangue , Hemoglobinas Glicadas/metabolismo , Hematínicos/administração & dosagem , Polietilenoglicóis/administração & dosagem , Diálise Renal , Insuficiência Renal Crônica , Adulto , Idoso , Idoso de 80 Anos ou mais , Nefropatias Diabéticas/sangue , Nefropatias Diabéticas/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/terapiaRESUMO
Freshly isolated human hematopoietic stem and progenitor cells (HSPCs) are small and round cells which upon cultivation adopt a polarized morphology and redistribute certain cell surface antigens. To functionally dissect this polarization process, we addressed impacts of protein synthesis, HSPC trafficking, cytoskeleton organization or lipid raft integrity on the establishment and maintenance of the cell polarity of human HSPCs. Effects on the morphology, sub-cellular distribution of lipid raft-associated molecular polarization markers (Flotillin-1, Flotillin-2, ICAM-3) and in vitro migration capabilities of treated cells were studied. We could distinguish two levels of cellular polarization, a molecular and a morphological level. Our data suggest that protein synthesis, lipid raft integrity and enzymatic activities of PI3K and aPKC are required to organize the molecular cell polarity. The morphological cell polarization process, however, also depends on actin polymerization and rho-GTPase activities. In summary, our data qualify HSPC polarization processes as new pharmaceutical target to interfere with migratory and with homing capabilities of HSPCs.
Assuntos
Movimento Celular/fisiologia , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Microdomínios da Membrana/metabolismo , Células-Tronco/citologia , Células-Tronco/metabolismo , Animais , Moléculas de Adesão Celular/metabolismo , Polaridade Celular/fisiologia , Humanos , Immunoblotting , Camundongos , Camundongos Endogâmicos NODRESUMO
Calcimimetics increase the sensitivity of the parathyroid calcium-sensing receptor to extracellular calcium for efficient control of hyperparathyroidism. Recent studies suggest that there are beneficial effects of calcimimetics beyond the control of bone and mineral homeostasis. Here, we tested whether the calcium-sensing receptor is also expressed and functionally relevant in podocytes. Analysis of microarray data using Gene Set Enrichment Analysis found that the calcimimetic R-568 influenced various pathways related to oxidative stress, cytoskeletal regulation, cell proliferation, and survival in cultured podocytes. R-568 induced a dose- and time-dependent phosphorylation of the ERK1/2-P90RSK-CREB signaling cascade, and induced pro-survival phosphorylation of BAD and Bcl-xl, thus reducing puromycin aminonucleoside (PAN)-induced podocyte apoptosis by half. Moreover, R-568 preserved the actin cytoskeleton in podocytes exposed to PAN and improved recovery from exposure to cytochalasin D, a reversible inhibitor of actin polymerization. In rats, co-administration of R-568 prevented the proteinuria caused by a single dose of PAN and attenuated the glomerulosclerosis and loss of GFR caused by repetitive puromycin treatment. Hence, calcimimetics limit podocyte damage by antiapoptotic and cytoskeleton-stabilizing effects and may constitute a new approach in the prevention and treatment of glomerular disease.
Assuntos
Citoesqueleto/metabolismo , Glomerulosclerose Segmentar e Focal/tratamento farmacológico , Podócitos/citologia , Receptores de Detecção de Cálcio/metabolismo , Compostos de Anilina/farmacologia , Animais , Calcimiméticos/farmacologia , Sobrevivência Celular , Glomerulosclerose Segmentar e Focal/induzido quimicamente , Fenetilaminas , Propilaminas , Ratos , Receptores de Detecção de Cálcio/fisiologiaRESUMO
BACKGROUND: Migration of mature and immature leukocytes in response to chemokines is not only essential during inflammation and host defense, but also during development of the hematopoietic system. Many molecules implicated in migratory polarity show uniform cellular distribution under non-activated conditions, but acquire a polarized localization upon exposure to migratory cues. METHODOLOGY/PRINCIPAL FINDINGS: Here, we present evidence that raft-associated endocytic proteins (flotillins) are pre-assembled in lymphoid, myeloid and primitive hematopoietic cells and accumulate in the uropod during migration. Furthermore, flotillins display a polarized distribution during immunological synapse formation. Employing the membrane lipid-order sensitive probe Laurdan, we show that flotillin accumulation in the immunological synapse is concomittant with membrane ordering in these regions. CONCLUSIONS: Together with the observation that flotillin polarization does not occur in other polarized cell types such as polarized epithelial cells, our results suggest a specific role for flotillins in hematopoietic cell polarization. Based on our results, we propose that in hematopoietic cells, flotillins provide intrinsic cues that govern segregation of certain microdomain-associated molecules during immune cell polarization.
Assuntos
Polaridade Celular , Células-Tronco Hematopoéticas/citologia , Proteínas de Membrana/metabolismo , Actinas/metabolismo , Animais , Antígenos CD34/metabolismo , Biomarcadores/metabolismo , Diferenciação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Polaridade Celular/efeitos dos fármacos , Quimiocina CXCL12/farmacologia , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Cães , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Humanos , Sinapses Imunológicas/efeitos dos fármacos , Sinapses Imunológicas/metabolismo , Microdomínios da Membrana/efeitos dos fármacos , Microdomínios da Membrana/metabolismo , Monócitos/citologia , Monócitos/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Pseudópodes/efeitos dos fármacos , Pseudópodes/metabolismo , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacosRESUMO
Hematopoietic stem cells (HSC) are undifferentiated cells, which self-renew over a long period of time and give rise to committed hematopoietic progenitor cells (HPC) containing the capability to replenish the whole blood system. Since both uncontrolled expansion as well as loss of HSC would be fatal, the decision of self-renewal versus differentiation needs to be tightly controlled. There is good evidence that both HSC niches as well as asymmetric cell divisions are involved in controlling whether HSC self-renew or become committed to differentiate. In this context, we recently identified four proteins which frequently segregate asymmetrically in dividing HSC/HPC. Remarkably, three of these proteins, the tetraspanins CD53 and CD63, and the transferrin receptor are endosome-associated proteins. Here, we highlight these observations in conjunction with recent findings in model organisms which show that components of the endosomal machinery are involved in cell-fate specification processes.
Assuntos
Divisão Celular , Endossomos , Células-Tronco Hematopoéticas/citologia , Animais , Divisão Celular/fisiologia , Endossomos/fisiologia , Células-Tronco Hematopoéticas/fisiologia , Humanos , Células-Tronco/citologia , Células-Tronco/fisiologiaRESUMO
Phototrophic organisms use photosynthesis to convert solar energy into chemical energy. In nature, the chemical energy is stored in a diverse range of biopolymers. These sunlight-derived, energy-rich biopolymers can be converted into environmentally clean and CO(2) neutral fuels. A select group of photosynthetic microorganisms have developed the ability to extract and divert protons and electrons derived from water to chloroplast hydrogenase(s) to produce molecular H(2) fuel. Here, we describe the development and characterization of C. reinhardtii strains, derived from the high H(2) production mutant Stm6, into which the HUP1 (hexose uptake protein) hexose symporter from Chlorella kessleri was introduced. The isolated cell lines can use externally supplied glucose for heterotrophic growth in the dark. More importantly, external glucose supply (1mM) was shown to increase the H(2) production capacity in strain Stm6Glc4 to approximately 150% of that of the high-H(2) producing strain, Stm6. This establishes the foundations for a new fuel production process in which H(2)O and glucose can simultaneously be used for H(2) production. It also opens new perspectives on future strategies for improving bio-H(2) production efficiency under natural day/night regimes and for using sugar waste material for energy production in green algae as photosynthetic catalysts.
Assuntos
Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/metabolismo , Genoma de Protozoário/genética , Hidrogênio/metabolismo , Proteínas de Transporte de Monossacarídeos/genética , Simportadores/genética , Animais , Metabolismo dos Carboidratos/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Chlamydomonas reinhardtii/citologia , Chlamydomonas reinhardtii/efeitos dos fármacos , Escuridão , Vetores Genéticos , Glucose/farmacologia , Processos Heterotróficos/efeitos dos fármacos , Transformação Genética/efeitos dos fármacosRESUMO
The findings that many primitive human hematopoietic cells give rise to daughter cells that adopt different cell fates and/or show different proliferation kinetics suggest that hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) can divide asymmetrically. However, definitive experimental demonstration is lacking due to the current absence of asymmetrically segregating marker molecules within the primitive hematopoietic cell compartment. Thus, it remains an open question as to whether HSCs/HPCs have the capability to divide asymmetrically, or whether the differences that have been observed are established by extrinsic mechanisms that act on postmitotic progenitors. Here, we have identified 4 proteins (CD53, CD62L/L-selectin, CD63/lamp-3, and CD71/transferrin receptor) that segregate differentially in about 20% of primitive human hematopoietic cells that divide in stroma-free cultures. Therefore, this indicates for the first time that HSCs/HPCs have the capability to divide asymmetrically. Remarkably, these proteins, in combination with the surrogate stem-cell marker CD133, help to discriminate the more primitive human cultivated HSCs/HPCs. Since 3 of these proteins, the transferrin receptor and the tetraspanins CD53 and CD63, are endosomal-associated proteins, they may provide a link between the endosomal compartment and the process of asymmetric cell division within the HSC/HPC compartment.
Assuntos
Compartimento Celular , Divisão Celular , Células-Tronco Hematopoéticas/citologia , Proteínas/metabolismo , Antígenos CD , Antígenos de Diferenciação de Linfócitos T , Biomarcadores , Células Cultivadas , Endossomos , Células-Tronco Hematopoéticas/metabolismo , Humanos , Selectina L , Glicoproteínas da Membrana de Plaquetas , Transporte Proteico , Receptores da Transferrina , Tetraspanina 25 , Tetraspanina 30RESUMO
The expression of the proteins encoded by human papillomaviruses (HPVs) is tightly linked to the differentiation program of the infected keratinocytes. The late promoter, expressing the structural proteins, becomes activated in the differentiated keratinocytes, while the early promoter is also active in the basal layers. We have shown previously that the viral transcriptional regulator E2 and the cellular coactivator p300 cooperate in activation of gene expression of HPV8, which infects the skin and is associated with epidermodysplasia verruciformis. Here we demonstrate that this activation is further stimulated after overexpression of the E6 oncoprotein of HPV8 (8E6). RNase protection experiments revealed that 8E6 efficiently cooperates with 8E2 and p300 in activation of the late promoter. In addition, the early promoter, which did not respond to 8E2 and/or p300, was stimulated more than fourfold by 8E6. Our data suggest that both promoters are activated via distinct mechanisms, since the activation of the early promoter was achieved by the N-terminal moiety of 8E6; in contrast, its C-terminal half was sufficient for late promoter activation. This was markedly reduced by the deletion of amino acids 132 to 136 of 8E6, which also abolished the binding to p300, indicating that a direct interaction between 8E6 and p300 is involved. Moreover, a 45-amino-acid segment within the C/H3 region of p300 is required for 8E6 to stimulate the coactivator function of p300. Our results demonstrate for the first time that an E6 oncoprotein of HPV directly contributes to the regulation of HPV gene expression.
Assuntos
Regulação Viral da Expressão Gênica , Queratinócitos/virologia , Proteínas Oncogênicas Virais/metabolismo , Papillomaviridae/metabolismo , Regiões Promotoras Genéticas , Linhagem Celular , Humanos , Mutagênese Sítio-Dirigida , Proteínas Oncogênicas Virais/química , Proteínas Oncogênicas Virais/genética , Papillomaviridae/genética , Transativadores/metabolismo , Transfecção , Fatores de Transcrição de p300-CBP/metabolismoRESUMO
The targeted manipulation of the genetic program of single cells as well as of complete organisms has strongly enhanced our understanding of cellular and developmental processes and should also help to increase our knowledge of primary human stem cells, e.g., hematopoietic stem cells (HSCs), within the next few years. An essential requirement for such genetic approaches is the existence of a reliable and efficient method to introduce genetic elements into living cells. Retro- and lentiviral techniques are efficient in transducing primary human HSCs, but remain labor and time consuming and require special safety conditions, which do not exist in many laboratories. In our study, we have optimized the nucleofection technology, a modified electroporation strategy, to introduce plasmid DNA into freshly isolated human HSC-enriched CD34(+) cells. Using enhanced green fluorescent protein (eGFP)-encoding plasmids, we obtained transfection efficiencies of approximately 80% and a mean survival rate of 50%. Performing functional assays using GFU-GEMM and long-term culture initiating cells (LTC-IC), we demonstrate that apart from a reduction in the survival rate the nucleofection method itself does not recognizably change the short- or long-term cell fate of primitive hematopoietic cells. Therefore, we conclude, the nucleofection method is a reliable and efficient method to manipulate primitive hematopoietic cells genetically.
Assuntos
Células-Tronco Hematopoéticas/metabolismo , Transfecção/métodos , Antígeno AC133 , Clorometilcetonas de Aminoácidos/farmacologia , Animais , Antígenos CD/análise , Antígenos CD34/análise , Técnicas de Cultura de Células/métodos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Separação Celular , Sobrevivência Celular/efeitos dos fármacos , Ensaio de Unidades Formadoras de Colônias , Eletroporação/métodos , Eritrócitos/citologia , Eritrócitos/metabolismo , Sangue Fetal/citologia , Citometria de Fluxo , Glicoproteínas/análise , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Células-Tronco Hematopoéticas/química , Células-Tronco Hematopoéticas/citologia , Humanos , Leucócitos/citologia , Leucócitos/metabolismo , Microscopia de Fluorescência , Peptídeos/análise , Células Estromais/citologiaRESUMO
It is often predicted that stem cells divide asymmetrically, creating a daughter cell that maintains the stem-cell capacity, and 1 daughter cell committed to differentiation. While asymmetric stem-cell divisions have been proven to occur in model organisms (eg, in Drosophila), it remains illusive whether primitive hematopoietic cells in mammals actually can divide asymmetrically. In our experiments we have challenged this question and analyzed the developmental capacity of separated offspring of primitive human hematopoietic cells at a single-cell level. We show for the first time that the vast majority of the most primitive, in vitro-detectable human hematopoietic cells give rise to daughter cells adopting different cell fates; 1 inheriting the developmental capacity of the mother cell, and 1 becoming more specified. In contrast, approximately half of the committed progenitor cells studied gave rise to daughter cells, both of which adopted the cell fate of their mother. Although our data are compatible with the model of asymmetric cell division, other mechanisms of cell fate specification are discussed. In addition, we describe a novel human hematopoietic progenitor cell that has the capacity to form natural killer (NK) cells as well as macrophages, but not cells of other myeloid lineages.
Assuntos
Diferenciação Celular/fisiologia , Células-Tronco Hematopoéticas/fisiologia , Células Matadoras Naturais/fisiologia , Linfopoese/fisiologia , Modelos Biológicos , Animais , Células Cultivadas , Drosophila , Células-Tronco Hematopoéticas/citologia , Humanos , Células Matadoras Naturais/citologiaRESUMO
During ontogenesis and the entire adult life hematopoietic stem and progenitor cells have the capability to migrate. In comparison to the process of peripheral leukocyte migration in inflammatory responses, the molecular and cellular mechanisms governing the migration of these cells remain poorly understood. A common feature of migrating cells is that they need to become polarized before they migrate. Here we have investigated the issue of cell polarity of hematopoietic stem/progenitor cells in detail. We found that human CD34(+) hematopoietic cells (1) acquire a polarized cell shape upon cultivation, with the formation of a leading edge at the front pole and a uropod at the rear pole; (2) exhibit an amoeboid movement, which is similar to the one described for migrating peripheral leukocytes; and (3) redistribute several lipid raft markers including cholesterol-binding protein prominin-1 (CD133) in specialized plasma membrane domains. Furthermore, polarization of CD34(+) cells is stimulated by early acting cytokines and requires the activity of phosphoinositol-3-kinase as previously reported for peripheral leukocyte polarization. Together, our data reveal a strong correlation between polarization and migration of peripheral leukocytes and hematopoietic stem/progenitor cells and suggest that they are governed by similar mechanisms.