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Memory T selected cells (CD45RA-/RO+) as donor lymphocyte infusion are less capable of producing alloreactivity and graft versus host disease (GvHD) compared with naïve T cells. The objective of this study was to evaluate the safety and efficacy of high-dose memory (CD45RA-/RO+) donor lymphocyte infusion (mDLI) after allogeneic hematopoietic cell transplantation (HCT). Indications for mDLI were "as needed" and "as prophylactic regimen." Sixty-one children diagnosed with malignant (82%) and non-malignant diseases (18%) received 241 mDLIs. Patients received a median of three infusions (range 1â13) of mDLI with a median infused dose of 1.35 × 107/kg CD45RO+ containing 8.96 × 106/kg CD3+CD45RO+ and 3.81 × 103/kg CD3+CD45RA+. De novo GvHD developed in 7 patients following 4% of the mDLI infusions. Among patients with GvHD before mDLI, this condition worsened following 6 infusions (11%) in the 3 patients with grade II-IV acute GvHD. A decrease in cytomegalovirus viral load followed 65% of mDLI infusions. Two-year overall survival (OS) for the total cohort was 64% (95% CI 57%â72%). For patients receiving prophylactic mDLI, the two-year non-relapse mortality was 10% (95% CI 9%â11%). In summary, high-dose mDLI is feasible and safe, with a relatively low risk of severe GvHD even in patients with active GvHD. Importantly, mDLI was associated with positive effects, including enhanced control of CMV viremia.
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BACKGROUND: Mitogen-activated protein kinases (MAPKs) preserve cell homeostasis by transducing physicochemical fluctuations of the environment into multiple adaptive responses. These responses involve transcriptional rewiring and the regulation of cell cycle transitions, among others. However, how stress conditions impinge mitotic progression is largely unknown. The mitotic checkpoint is a surveillance mechanism that inhibits mitotic exit in situations of defective chromosome capture, thus preventing the generation of aneuploidies. In this study, we investigate the role of MAPK Pmk1 in the regulation of mitotic exit upon stress. RESULTS: We show that Schizosaccharomyces pombe cells lacking Pmk1, the MAP kinase effector of the cell integrity pathway (CIP), are hypersensitive to microtubule damage and defective in maintaining a metaphase arrest. Epistasis analysis suggests that Pmk1 is involved in maintaining spindle assembly checkpoint (SAC) signaling, and its deletion is additive to the lack of core SAC components such as Mad2 and Mad3. Strikingly, pmk1Δ cells show up to twofold increased levels of the anaphase-promoting complex (APC/C) activator Cdc20Slp1 during unperturbed growth. We demonstrate that Pmk1 physically interacts with Cdc20Slp1 N-terminus through a canonical MAPK docking site. Most important, the Cdc20Slp1 pool is rapidly degraded in stressed cells undergoing mitosis through a mechanism that requires MAPK activity, Mad3, and the proteasome, thus resulting in a delayed mitotic exit. CONCLUSIONS: Our data reveal a novel function of MAPK in preventing mitotic exit and activation of cytokinesis in response to stress. The regulation of Cdc20Slp1 turnover by MAPK Pmk1 provides a key mechanism by which the timing of mitotic exit can be adjusted relative to environmental conditions.
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Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Ciclosoma-Complejo Promotor de la Anafase/genética , Ciclosoma-Complejo Promotor de la Anafase/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Proteínas Cdc20/genética , Proteínas Cdc20/metabolismo , Proteínas de Ciclo Celular/metabolismo , Mitosis , Huso Acromático/metabolismoRESUMEN
Still's disease, the paradigm of autoinflammation-cum-autoimmunity, predisposes for a cytokine storm with excessive T lymphocyte activation upon viral infection. Loss of function of the purine nucleoside enzyme FAMIN is the sole known cause for monogenic Still's disease. Here we discovered that a FAMIN-enabled purine metabolon in dendritic cells (DCs) restrains CD4+ and CD8+ T cell priming. DCs with absent FAMIN activity prime for enhanced antigen-specific cytotoxicity, IFNγ secretion, and T cell expansion, resulting in excessive influenza A virus-specific responses. Enhanced priming is already manifest with hypomorphic FAMIN-I254V, for which â¼6% of mankind is homozygous. FAMIN controls membrane trafficking and restrains antigen presentation in an NADH/NAD+-dependent manner by balancing flux through adenine-guanine nucleotide interconversion cycles. FAMIN additionally converts hypoxanthine into inosine, which DCs release to dampen T cell activation. Compromised FAMIN consequently enhances immunosurveillance of syngeneic tumors. FAMIN is a biochemical checkpoint that protects against excessive antiviral T cell responses, autoimmunity, and autoinflammation.
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Autoinmunidad , Purinas , Linfocitos T CD8-positivos , Células Dendríticas , Activación de Linfocitos , Purinas/metabolismoRESUMEN
BACKGROUND: Naïve T-cell-depleted grafts have been employed as an ex vivo T-cell depletion (TCD) platform to prevent graft-versus-host disease (GvHD) and improve immune reconstitution by providing rapid donor memory T-cell reconstitution after allogenic hematopoietic stem cell transplantation (allo-HSCT). CD45RA- memory T cells confer protection against viruses such as cytomegalovirus, Epstein-Barr virus, and adenovirus; however, reports have shown an unexpectedly high incidence of human herpesvirus (HHV)-6B encephalitis among pediatric allo-HSCT patients. METHODS: We report the first 18 consecutive allo-HSCT, 16 haplo-HSCT, and two human leukocyte antigen-matched related donors implanted with naïve TCD grafts. All donors were administered three cell products: first, a CD34+ stem cell product; second, a CD45RA+ TCD graft, followed by an adoptive natural killer (NK) cell infusion within 10 days after HSCT. The study's primary endpoint was the incidence of HHV-6B encephalitis. RESULTS: Engraftment was achieved in 94.5% of cases; 2-year overall survival, event-free survival, and GvHD/relapse-free survival were 87.2% (95% CI 78.6-95.8), 67.3% (95% CI 53.1-81.5), and 64% (95% CI 50.5-78.1), respectively. HHV-6B reactivation occurred in 7 of the haplo-HSCT patients, six of who received a cell infusion with an NK/CD4 ratio <2. None of the patients developed encephalitis. CONCLUSIONS: In this clinical study, we show that early adoptive NK cell infusion after a 45RA+ TCD allo-HSCT graft is safe and can prevent HHV-6B encephalitis. We recommend infusing adoptive NK cells after allo-HSCT using CD45RA+ TCD grafts.
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Encefalitis/prevención & control , Trasplante de Células Madre Hematopoyéticas , Herpesvirus Humano 6/aislamiento & purificación , Células Asesinas Naturales/trasplante , Depleción Linfocítica , Infecciones por Roseolovirus/prevención & control , Adolescente , Traslado Adoptivo/métodos , Niño , Preescolar , Encefalitis/inmunología , Femenino , Enfermedad Injerto contra Huésped/inmunología , Enfermedad Injerto contra Huésped/prevención & control , Trasplante de Células Madre Hematopoyéticas/métodos , Herpesvirus Humano 6/inmunología , Humanos , Lactante , Células Asesinas Naturales/inmunología , Masculino , Infecciones por Roseolovirus/inmunología , Linfocitos T/inmunología , Trasplante Homólogo/métodosRESUMEN
Severe aplastic anemia and congenital amegakaryocytic thrombocytopenia are rare bone marrow failure syndromes. Treatment for aplastic anemia consists of hematopoietic stem cell transplantation (HSCT) from a matched sibling donor or immunosuppressant drugs if there is no donor available. Congenital amegakaryocytic thrombocytopenia is a rare autosomal recessive disease that causes bone marrow failure and has limited treatment options, except for transfusion support and HSCT. In the absence of a suitable matched sibling donor, matched-unrelated, haploidentical, or mismatched donors may be considered. A 2-step partial T-cell-depletion strategy can remove CD45RA+ naïve T cells responsible for graft-versus-host disease (GvHD) while preserving memory T cells. Five patients underwent transplantation using this strategy with rapid neutrophil and platelet recovery. Acute and chronic GvHD ≥ grade 2 appeared in two and one patient, respectively. No severe infections were observed before day + 100. A high (60%) incidence of transplant-associated microangiopathy was observed. Three patients (60%) remain alive, with a median follow-up of 881 (range 323-1248) days. CD45RA-depleted HSCT is a novel approach for patients lacking a suitable matched donor; however, further improvements are needed.
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Antígenos HLA/inmunología , Trasplante de Células Madre Hematopoyéticas/métodos , Antígenos Comunes de Leucocito/inmunología , Linfocitos T/inmunología , Adolescente , Anemia Aplásica/terapia , Niño , Preescolar , Femenino , Enfermedad Injerto contra Huésped/etiología , Enfermedad Injerto contra Huésped/inmunología , Humanos , Reconstitución Inmune , Depleción Linfocítica , Masculino , Acondicionamiento Pretrasplante/métodosRESUMEN
BACKGROUND: Tofacitinib and other new treatments approved for use in psoriatic arthritis have only recently been included in psoriatic arthritis treatment guidelines, and studies evaluating the relative efficacy of available therapies are important to inform treatment decisions by healthcare professionals. OBJECTIVE: To perform a network meta-analysis to evaluate the efficacy and safety profiles of tofacitinib, biologic disease-modifying antirheumatic drugs (bDMARDs), and apremilast in patients with psoriatic arthritis naïve to tumor necrosis factor inhibitor therapy (TNFi-naïve) or with an inadequate response (TNFi-IR). METHODS: A systematic literature review used searches of MEDLINE, Embase, and The Cochrane Library on October 9, 2017. Randomized controlled trials including adult patients with psoriatic arthritis receiving treatment administered as monotherapy or with conventional synthetic DMARDs were selected. Efficacy outcomes included American College of Rheumatology 20 response, change from baseline in Health Assessment Questionnaire-Disability Index, ≥75% improvement in Psoriasis Area and Severity Index, and change from baseline in Dactylitis Severity Score and Leeds Enthesitis Index. Treatment effects were evaluated during placebo-controlled phases, using a binomial logit model for binary outcomes and a normal identify link model for other outcomes. Discontinuations due to adverse events and serious infection events were assessed as safety outcomes. RESULTS: The network meta-analysis included 24 published randomized controlled trials, of which 13 enrolled TNFi-naïve patients only, 3 enrolled TNFi-IR patients only, and 8 enrolled both TNFi-naïve and TNFi-IR patients. Placebo-controlled treatment durations ranged from 12 to 24 weeks. Indirect comparisons showed tofacitinib 5 and 10 mg BID to have similar efficacy compared with most bDMARDs and apremilast in improving joint symptoms (based on American College of Rheumatology 20 response), and with some bDMARDs in improving skin symptoms (based on Psoriasis Area and Severity Index) (tofacitinib 10 mg BID only in TNFi-IR) in patients with psoriatic arthritis who were TNFi-naïve or TNFi-IR. Results also showed that, compared with placebo, the improvement in physical functioning (based on Health Assessment Questionnaire-Disability Index) with tofacitinib 5 and 10 mg BID was similar to that observed with most bDMARDs and apremilast in TNFi-naïve patients, and similar to that observed with all bDMARDs with available data in the TNFi-IR population. Improvements in Dactylitis Severity Score and Leeds Enthesitis Index scores were comparable between treatments. Tofacitinib 5 and 10 mg BID were median-ranked 8 and 15, respectively, for discontinuation due to any adverse events, and 5 and 16, respectively, for a serious infection event out of a total of 20 treatments in the network (lower numbers are more favorable). CONCLUSIONS: Tofacitinib provides an additional treatment option for patients with psoriatic arthritis, both in patients naïve to TNFi and in those with TNFi-IR. (Curr Ther Res Clin Exp. 2020; 81:XXX-XXX).
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OBJECTIVE: Metabolic syndrome (MetS) is a cluster of concurrent risk factors for cardiovascular disease and type 2 diabetes. This post hoc analysis explored key efficacy and safety endpoints in patients with psoriatic arthritis (PsA) and MetS treated with tofacitinib. METHODS: Tofacitinib 5 and 10 mg twice daily and placebo data were pooled from two Phase 3 studies (OPAL Broaden [12 months; ClinicalTrials.gov identifier NCT01877668]; OPAL Beyond [6 months; ClinicalTrials.gov identifier NCT01882439]); patients received one background conventional synthetic disease-modifying antirheumatic drug. Patients were stratified by baseline presence/absence of MetS. Efficacy and safety were reported to month 3 (tofacitinib and placebo) and 6 (tofacitinib only). Efficacy outcomes included: American College of Rheumatology (ACR)20/50/70, Health Assessment Questionnaire-Disability Index (HAQ-DI) response, Psoriasis Area Severity Index (PASI)75 response, and enthesitis/dactylitis resolution rates; and changes from baseline (Δ) in C-reactive protein, HAQ-DI, Patient's/Physician's Global Assessment of Arthritis, and patient-reported outcomes. Safety outcomes included treatment-emergent all-causality adverse events (AEs), Δ in lipid/hepatic values, and liver parameter increases. RESULTS: Of 710 patients, 41.4% (n = 294) had baseline MetS. All efficacy outcomes improved with both tofacitinib doses versus placebo, to month 3; tofacitinib efficacy was consistent to month 6, regardless of MetS status. MetS did not appear to affect the incidence of AEs or Δ in lipid/hepatic values with tofacitinib up to month 3 or 6. Arterial thromboembolism and myocardial infarction (adjudicated major adverse cardiovascular events) were each reported once in tofacitinib-treated patients with MetS. CONCLUSION: Regardless of baseline MetS status, tofacitinib showed greater efficacy versus placebo in patients with active PsA. The tofacitinib safety profile appeared similar in patients with versus without MetS.
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INTRODUCTION: Tofacitinib is an oral Janus kinase inhibitor for the treatment of psoriatic arthritis (PsA). We report the interim safety, tolerability, and efficacy of tofacitinib in PsA patients in OPAL Balance, a 3-year, open-label, long-term extension study (data cut-off: August 2017; database not locked, data may change). METHODS: Eligible patients from two phase (P) 3 (P3) tofacitinib PsA studies (OPAL Broaden, NCT01877668; OPAL Beyond, NCT01882439) entered OPAL Balance ≤ 3 months after completing the P3 study or discontinuing for reasons other than study-drug-related adverse events (AEs). Patients received open-label tofacitinib 5 mg twice daily (BID), with adjustments to 10 mg BID permitted post-month (M) 1. Certain concomitant conventional synthetic disease-modifying antirheumatic drugs were allowed. Primary endpoints were incidence/severity of AEs and laboratory abnormalities, and changes from baseline in laboratory parameters (reported up to M36 and M30, respectively). Efficacy (clinical/patient-reported outcomes) was reported through M30. RESULTS: A total of 686 patients were treated; at data cut-off, 68.2% remained in the study. Mean (range) treatment duration was 641 (1-1032) days; total treatment duration was 1153.2 patient-years. By M36, 79.6, 13.8, and 8.6% of patients reported AEs, serious AEs, and discontinuations due to AEs, respectively. Five deaths occurred; one within the risk period (incidence rate [IR; patients with events/100 patient-years] 0.1). IRs for AEs of special interest were: all (non-serious and serious) herpes zoster, 1.7; serious infections, 0.9; opportunistic infections, 0.3 (all disseminated/multi-dermatomal herpes zoster); malignancies excluding non-melanoma skin cancer (NMSC), 0.8; NMSC, 1.0; major adverse cardiovascular events, 0.3; pulmonary embolisms, 0.1; and arterial thromboembolisms, 0.4. No patients had deep vein thrombosis. Alanine aminotransferase and aspartate aminotransferase levels were elevated ≥ 3-fold the upper limit of normal in 4.0 and 2.2% of patients, respectively. Changes in laboratory parameters were generally stable over time, although lymphocyte counts decreased slightly. Efficacy was maintained through M30. CONCLUSIONS: In this interim analysis of OPAL Balance, tofacitinib safety and efficacy in patients with PsA appeared to be consistent with those of the P3 studies. Efficacy was maintained over time. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01976364.
In many countries, tofacitinib is an approved medicine that can be used to treat psoriatic arthritis (PsA). In the study reported here (OPAL Balance), adult patients with PsA took tofacitinib for up to 3 years. We report a planned interim analysis, i.e., an analysis of information collected before the study finished. This early information suggests that the safety of tofacitinib, and how well it improved symptoms and quality of life (efficacy), was similar in this long study as in shorter studies. Information from the finished study will be reported later. OPAL Balance started on 17 February 2014. This interim analysis includes information collected by 31 August 2017. Before joining, patients had finished a 6-month or 12-month tofacitinib study (OPAL Broaden or OPAL Beyond). Patients in OPAL Balance took a 5 mg tofacitinib pill twice a day, but if PsA symptoms did not improve after 1 month, they could take a 10 mg pill twice a day. They could also take other medicines (including methotrexate or corticosteroids). Of the 686 patients who took tofacitinib, 546 (80%) experienced side effects over 3 years. These were considered serious for 95 patients (14%) and caused 59 patients (9%) to leave the study. Five patients died from causes not related to tofacitinib. Known tofacitinib side effects, including shingles (herpes zoster), serious infections (needing hospitalization), infections in patients with weakened immune systems, cancer, heart (cardiovascular) problems, and vein blockages (embolisms), were each reported by fewer than 20 patients. Most blood test results and tofacitinib efficacy were stable over 2.5 years.
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Mutations in FAMIN cause arthritis and inflammatory bowel disease in early childhood, and a common genetic variant increases the risk for Crohn's disease and leprosy. We developed an unbiased liquid chromatography-mass spectrometry screen for enzymatic activity of this orphan protein. We report that FAMIN phosphorolytically cleaves adenosine into adenine and ribose-1-phosphate. Such activity was considered absent from eukaryotic metabolism. FAMIN and its prokaryotic orthologs additionally have adenosine deaminase, purine nucleoside phosphorylase, and S-methyl-5'-thioadenosine phosphorylase activity, hence, combine activities of the namesake enzymes of central purine metabolism. FAMIN enables in macrophages a purine nucleotide cycle (PNC) between adenosine and inosine monophosphate and adenylosuccinate, which consumes aspartate and releases fumarate in a manner involving fatty acid oxidation and ATP-citrate lyase activity. This macrophage PNC synchronizes mitochondrial activity with glycolysis by balancing electron transfer to mitochondria, thereby supporting glycolytic activity and promoting oxidative phosphorylation and mitochondrial H+ and phosphate recycling.
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Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Adenina/metabolismo , Adenosina/metabolismo , Adenosina Desaminasa/metabolismo , Cromatografía Liquida/métodos , Células HEK293 , Células Hep G2 , Humanos , Péptidos y Proteínas de Señalización Intracelular/fisiología , Espectrometría de Masas/métodos , Enzimas Multifuncionales/genética , Fosforilación , Proteínas/genética , Nucleótidos de Purina/metabolismo , Purinas/metabolismoRESUMEN
INTRODUCTION: This study was intended to assess the efficacy and safety of a rosehip seed oil (RHO) extract in the prevention and treatment of skin lesions in the hands of patients with type 1 diabetes mellitus (T1DM) caused by finger prick blood glucose monitoring. PATIENTS AND METHOD: A prospective, randomized, controlled, open-label, rater-blinded trial in patients aged 6-17 years with T1DM and intensive blood glucose control (≥7 finger pricks daily) for 12 days. Three main variables (erythema, skin thickening, and loss of skin integrity) were assessed using a scale ranging from 0 (absent) to 3 (severe involvement). The study was approved by the ethics committee of the hospital. RESULTS: Sixty-eight children, and thus 136 hands, were included; 80 hands received rosehip seed oil and 56 hands acted as controls. Baseline characteristics of both groups were similar, with 76.3% and 78.6% of the hands respectively showing skin lesions at study start. Median final global assessment was 0.10 (0.03; 0.30) in the group that received rosehip seed oil and 0.06 (0.00; 0.23) in the control group. A statistically significant improvement in global assessment was found in the control group (P=0.049). No significant differences were found when the medians of the other main variables were compared. No adverse effects were recorded. CONCLUSION: A high prevalence of skin lesions secondary to finger prick glucose monitoring, most of them mild lesions, was found at study start. Treatment with rosehip seed oil was safe and was not effective for improving skin lesions.
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Automonitorización de la Glucosa Sanguínea , Complicaciones de la Diabetes/tratamiento farmacológico , Complicaciones de la Diabetes/etiología , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/complicaciones , Dermatosis de la Mano/tratamiento farmacológico , Dermatosis de la Mano/etiología , Lesiones por Pinchazo de Aguja/complicaciones , Fitoterapia , Extractos Vegetales/uso terapéutico , Aceites de Plantas/uso terapéutico , Rosa , Piel/lesiones , Adolescente , Niño , Complicaciones de la Diabetes/prevención & control , Femenino , Dermatosis de la Mano/prevención & control , Humanos , Masculino , Extractos Vegetales/efectos adversos , Aceites de Plantas/efectos adversos , Estudios Prospectivos , Resultado del TratamientoRESUMEN
Natural killer group 2D (NKG2D) is a natural killer (NK) cell-activating receptor that recognizes different stress-induced ligands that are overexpressed in a variety of childhood and adult tumors. NKG2D chimeric antigen receptor (CAR) T cells have shown potent anticancer effects against different cancer types. A second-generation NKG2D CAR was generated by fusing full-length human NKG2D to 4-1BB costimulatory molecule and CD3ζ signaling domain. Patient-derived CAR T cells show limitations including inability to manufacture CAR T cells from the patients' own T cells, disease progression, and death prior to return of engineered cells. The use of allogeneic T cells for CAR therapy could be an attractive alternative, although undesirable graft vs. host reactions may occur. To avoid such adverse effects, we used CD45RA- memory T cells, a T-cell subset with less alloreactivity, as effector cells to express NKG2D CAR. In this study, we developed a protocol to obtain large-scale NKG2D CAR memory T cells for clinical use by using CliniMACS Prodigy, an automated closed system compliant with Good Manufacturing Practice (GMP) guidelines. CD45RA+ fraction was depleted from healthy donors' non-mobilized apheresis using CliniMACS CD45RA Reagent and CliniMACS Plus device. A total of 108 CD45RA- cells were cultured in TexMACS media supplemented with 100 IU/mL IL-2 and activated at day 0 with T Cell TransAct. Then, we used NKG2D-CD8TM-4-1BB-CD3ζ lentiviral vector for cell transduction (MOI = 2). NKG2D CAR T cells expanded between 10 and 13 days. Final cell products were analyzed to comply with the specifications derived from the quality and complementary controls carried out in accordance with the instructions of the Spanish Regulatory Agency of Medicines and Medical Devices (AEMPS) for the manufacture of investigational advanced therapy medicinal products (ATMPs). We performed four validations. The manufacturing protocol here described achieved large numbers of viable NKG2D CAR memory T cells with elevated levels of NKG2D CAR expression and highly cytotoxic against Jurkat and 531MII tumor target cells. CAR T cell final products met release criteria, except for one showing myc overexpression and another with viral copy number higher than five. Manufacturing of clinical-grade NKG2D CAR memory T cells using CliniMACS Prodigy is feasible and reproducible, widening clinical application of CAR T cell therapies.
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Técnicas de Cultivo de Célula , Ingeniería Celular , Memoria Inmunológica , Inmunoterapia Adoptiva , Subfamilia K de Receptores Similares a Lectina de Células NK , Neoplasias , Receptores Quiméricos de Antígenos , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral , Humanos , Subfamilia K de Receptores Similares a Lectina de Células NK/genética , Subfamilia K de Receptores Similares a Lectina de Células NK/inmunología , Neoplasias/genética , Neoplasias/inmunología , Neoplasias/terapia , Receptores Quiméricos de Antígenos/genética , Receptores Quiméricos de Antígenos/inmunología , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/genética , Miembro 9 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/inmunologíaRESUMEN
The organization and number of microtubules (MTs) in a cell depend on the proper regulation of MT nucleation. Currently, the mechanism of nucleation is the most poorly understood aspect of MT dynamics. XMAP215/chTOG/Alp14/Stu2 proteins are MT polymerases that stimulate MT polymerization at MT plus ends by binding and releasing tubulin dimers. Although these proteins also localize to MT organizing centers and have nucleating activity in vitro, it is not yet clear whether these proteins participate in MT nucleation in vivo. Here, we demonstrate that in the fission yeast Schizosaccharomyces pombe, the XMAP215 ortholog Alp14 is critical for efficient MT nucleation in vivo. In multiple assays, loss of Alp14 function led to reduced nucleation rate and numbers of interphase MT bundles. Conversely, activation of Alp14 led to increased nucleation frequency. Alp14 associated with Mto1 and γ-tubulin complex components, and artificially targeting Alp14 to the γ-tubulin ring complexes (γ-TuRCs) stimulated nucleation. In imaging individual nucleation events, we found that Alp14 transiently associated with a γ-tubulin particle shortly before the appearance of a new MT. The transforming acidic coiled-coil (TACC) ortholog Alp7 mediated the localization of Alp14 at nucleation sites but not plus ends, and was required for efficient nucleation but not for MT polymerization. Our findings provide the strongest evidence to date that Alp14 serves as a critical MT nucleation factor in vivo. We suggest a model in which Alp14 associates with the γ-tubulin complex in an Alp7-dependent manner to facilitate the assembly or stabilization of the nascent MT.
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Proteínas Asociadas a Microtúbulos/genética , Microtúbulos/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Schizosaccharomyces/genética , Interfase , Proteínas Asociadas a Microtúbulos/metabolismo , Centro Organizador de los Microtúbulos/metabolismo , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismoRESUMEN
In metazoans, the nuclear envelope (NE) breakdown (NEBD) occurs during "open" mitosis and meiosis. In the fission yeast Schizosaccharomyces pombe, the mitosis and the first meiotic division (MI) are "closed," during which the NE is maintained. Intriguingly, during the second meiotic division (MII), the NE is also maintained, but nuclear and cytoplasmic molecules are mixed similarly to open mitosis, a phenomenon of unknown biological significance called "virtual" NEBD (vNEBD). Here, we show that importin-α-dependent nucleocytoplasmic transport regulates spindle disassembly late in anaphase B at MI, as previously reported for mitosis. At MII, however, spindle dissolution is triggered by vNEBD early in anaphase B, a mechanism that short-circuits the nucleocytoplasmic transport system. We demonstrate that the sequential action of these two spindle disassembly systems regulates the spatiotemporal order and ploidy of the meiotic products.
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Meiosis/fisiología , Membrana Nuclear/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , Huso Acromático/metabolismo , alfa Carioferinas/metabolismo , Anafase/fisiología , Membrana Nuclear/enzimología , Schizosaccharomyces/genética , Proteínas de Schizosaccharomyces pombe/genética , Huso Acromático/genética , alfa Carioferinas/genéticaRESUMEN
OBJECTIVE: To compare the effectiveness of switching to rituximab (RTX) with switching to alternative tumour necrosis factor (TNF) antagonists in patients with rheumatoid arthritis (RA) failing on TNF antagonists. METHODS: A multicentre prospective 3-year observational study was performed in patients with RA treated with RTX or an alternative TNF antagonist. The baseline 28-joint disease activity score (DAS28) and Health Assessment Questionnaire (HAQ) score were compared with 6, 9 and 12 month values, adjusting for propensity score quintiles. Propensity scores were estimated for each patient using logistic regression with treatment as the dependent variable and baseline prior number of TNFs >1, years from diagnosis >5, extra-articular manifestations, previous toxicity, use of ≥2 disease-modifying antirheumatic drugs, age and sex as independent variables. RESULTS: 1124 patients were treated with either RTX (n=591, 52.6%) or alternative TNF antagonists (n=533, 47.4%). RTX-treated patients had longer disease duration (p=0.0001), larger numbers of previous TNF antagonists (p<0.0001) and tender and swollen joints (p<0.0001). There was no significant difference in the reduction in DAS28 at 6, 9 and 12 months between RTX-treated patients and those treated with TNF antagonists. However, the reduction in DAS28 was significantly different between RTX-treated patients and adalimumab/infliximab-treated patients (p=0.001 and p=0.05, respectively). There was a marginally significant difference at any time period in the proportion of patients achieving an improvement in the HAQ score of >0.22 (p=0.06). CONCLUSIONS: Optimal treatment for patients with RA failing on treatment with TNF antagonists may include RTX. This study suggests that the improvement in DAS28 is larger in patients treated with RTX than in those treated with monoclonal anti-TNF agents.