RESUMEN
A path to sustainably reduce world hunger, food insecurity, and malnutrition is to close the crop yield gap, particularly, losses due to pathogens. Breeding resistant crops is key to achieving this goal, an effort requiring collaboration among stakeholders, scientists, breeders, farmers and policymakers. During a disease outbreak, epidemiologists survey the occurrence of a disease after which pathologists investigate mechanisms to stop an infection. Policymakers then implement strategies with farmers and breeders to overcome the outbreak. Information flow from the field to the lab and back to the field involves several processing hubs that require different information inputs. Failure to communicate the necessary information results in the transfer of meaningless data. Here, we discuss gaps in information acquisition and transfer between the field and laboratory. Using rice bacterial blight disease as an example, we discuss pathogen biology and disease resistance to point out the importance of reporting pathogen strains that caused an outbreak to optimize the deployment of resistant crop varieties. We examine differences between infection in the field and assays performed in the laboratory to draw awareness of possible misinformation concerning plant resistance or susceptibility. We discuss key data considered useful for reporting disease outbreaks, sampling bias, and suggestions for improving data quality. We also touch on the knowledge gap in the state-of-the-art literature regarding disease dispersal and transmission. We use a recent case study to exemplify the gaps mentioned. We conclude by highlighting potential actions that may contribute to food security and to closing of the yield gap.
RESUMEN
Noonan syndrome (NS), the most common among RASopathies, is caused by germline variants in genes encoding components of the RAS-MAPK pathway. Distinct variants, including the recurrent Ser257Leu substitution in RAF1, are associated with severe hypertrophic cardiomyopathy (HCM). Here, we investigated the elusive mechanistic link between NS-associated RAF1S257L and HCM using three-dimensional cardiac bodies and bioartificial cardiac tissues generated from patient-derived induced pluripotent stem cells (iPSCs) harboring the pathogenic RAF1 c.770 C > T missense change. We characterize the molecular, structural, and functional consequences of aberrant RAF1-associated signaling on the cardiac models. Ultrastructural assessment of the sarcomere revealed a shortening of the I-bands along the Z disc area in both iPSC-derived RAF1S257L cardiomyocytes and myocardial tissue biopsies. The aforementioned changes correlated with the isoform shift of titin from a longer (N2BA) to a shorter isoform (N2B) that also affected the active force generation and contractile tensions. The genotype-phenotype correlation was confirmed using cardiomyocyte progeny of an isogenic gene-corrected RAF1S257L-iPSC line and was mainly reversed by MEK inhibition. Collectively, our findings uncovered a direct link between a RASopathy gene variant and the abnormal sarcomere structure resulting in a cardiac dysfunction that remarkably recapitulates the human disease.
Asunto(s)
Cardiomiopatía Hipertrófica , Síndrome de Noonan , Proteínas Proto-Oncogénicas c-raf , Humanos , Cardiomiopatía Hipertrófica/genética , Cardiomiopatía Hipertrófica/metabolismo , Cardiomiopatía Hipertrófica/patología , Mutación de Línea Germinal , Miocitos Cardíacos/metabolismo , Síndrome de Noonan/genética , Síndrome de Noonan/complicaciones , Síndrome de Noonan/metabolismo , Transducción de Señal , Proteínas Proto-Oncogénicas c-raf/genéticaRESUMEN
Bacterial leaf blight (BB) of rice, caused by Xanthomonas oryzae pv. oryzae (Xoo), threatens global food security and the livelihood of small-scale rice producers. Analyses of Xoo collections from Asia, Africa and the Americas demonstrated complete continental segregation, despite robust global rice trade. Here, we report unprecedented BB outbreaks in Tanzania. The causative strains, unlike endemic African Xoo, carry Asian-type TAL effectors targeting the sucrose transporter SWEET11a and iTALes suppressing Xa1. Phylogenomics clustered these strains with Xoo from Southern-China. African rice varieties do not carry effective resistance. To protect African rice production against this emerging threat, we developed a hybrid CRISPR-Cas9/Cpf1 system to edit all known TALe-binding elements in three SWEET promoters of the East African elite variety Komboka. The edited lines show broad-spectrum resistance against Asian and African strains of Xoo, including strains recently discovered in Tanzania. The strategy could help to protect global rice crops from BB pandemics.
Asunto(s)
Oryza , Xanthomonas , Edición Génica , Oryza/genética , Efectores Tipo Activadores de la Transcripción , Xanthomonas/genética , Tanzanía , Enfermedades de las Plantas/microbiología , Resistencia a la Enfermedad/genéticaRESUMEN
For the discovery of novel chemical matter generally endowed with bioactivity, strategies may be particularly efficient that combine previous insight about biological relevance, e.g., natural product (NP) structure, with methods that enable efficient coverage of chemical space, such as fragment-based design. We describe the de novo combination of different 5-membered NP-derived N-heteroatom fragments to structurally unprecedented "pseudo-natural products" in an efficient complexity-generating and enantioselective one-pot synthesis sequence. The pseudo-NPs inherit characteristic elements of NP structure but occupy areas of chemical space not covered by NP-derived chemotypes, and may have novel biological targets. Investigation of the pseudo-NPs in unbiased phenotypic assays and target identification led to the discovery of the first small-molecule ligand of the RHO GDP-dissociation inhibitor 1 (RHOGDI1), termed Rhonin. Rhonin inhibits the binding of the RHOGDI1 chaperone to GDP-bound RHO GTPases and alters the subcellular localization of RHO GTPases.
Asunto(s)
Productos Biológicos , Productos Biológicos/química , Ligandos , Proteínas de Unión al GTP rho , Inhibidor alfa de Disociación del Nucleótido Guanina rho , Inhibidores de la Disociación del Nucleótido Guanina rho-EspecíficoRESUMEN
Aberrant RHO guanine nucleotide exchange factor (RhoGEF) activation is chief mechanism driving abnormal activation of their GTPase targets in transformation and tumorigenesis. Consequently, a small-molecule inhibitor of RhoGEF can make an anti-cancer drug. We used cellular, mouse, and humanized models of RAC-dependent BCR-ABL1-driven and Ph-like acute lymphoblastic leukemia to identify VAV3, a tyrosine phosphorylation-dependent RacGEF, as the target of the small molecule IODVA1. We show that through binding to VAV3, IODVA1 inhibits RAC activation and signaling and increases pro-apoptotic activity in BCR-ABL1-transformed cells. Consistent with this mechanism of action, cellular and animal models of BCR-ABL1-induced leukemia in Vav3-null background do not respond to IODVA1. By durably decreasing in vivo RAC signaling, IODVA1 eradicates leukemic propagating activity of TKI-resistant BCR-ABL1(T315I) B-ALL cells after treatment withdrawal. Importantly, IODVA1 suppresses the leukemic burden in the treatment refractory pediatric Ph+ and TKI-resistant Ph+ B-ALL patient-derived xenograft models better than standard-of-care dasatinib or ponatinib and provides a more durable response after treatment withdrawal. Pediatric leukemia samples with diverse genetic lesions show high sensitivity to IODVA1 ex vivo and this sensitivity is VAV3 dependent. IODVA1 thus spearheads a novel class of drugs that inhibits a RacGEF and holds promise as an anti-tumor therapy.
Asunto(s)
Antineoplásicos/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-vav/antagonistas & inhibidores , Transducción de Señal/efectos de los fármacos , Animales , Antineoplásicos/uso terapéutico , Femenino , Humanos , Masculino , Ratones Endogámicos C57BL , Ratones SCID , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Proto-Oncogénicas c-vav/metabolismo , Bibliotecas de Moléculas Pequeñas/farmacología , Bibliotecas de Moléculas Pequeñas/uso terapéutico , Células Tumorales CultivadasRESUMEN
Hemophagocytic lymphohistiocytosis (HLH) is characterized by immune dysregulation due to inadequate restraint of overactivated immune cells and is associated with a variable clinical spectrum having overlap with more common pathophysiologies. HLH is difficult to diagnose and can be part of inflammatory syndromes. Here, we identify a novel hematological/autoinflammatory condition (NOCARH syndrome) in four unrelated patients with superimposable features, including neonatal-onset cytopenia with dyshematopoiesis, autoinflammation, rash, and HLH. Patients shared the same de novo CDC42 mutation (Chr1:22417990C>T, p.R186C) and altered hematopoietic compartment, immune dysregulation, and inflammation. CDC42 mutations had been associated with syndromic neurodevelopmental disorders. In vitro and in vivo assays documented unique effects of p.R186C on CDC42 localization and function, correlating with the distinctiveness of the trait. Emapalumab was critical to the survival of one patient, who underwent successful bone marrow transplantation. Early recognition of the disorder and establishment of treatment followed by bone marrow transplant are important to survival.
Asunto(s)
Susceptibilidad a Enfermedades , Linfohistiocitosis Hemofagocítica/diagnóstico , Linfohistiocitosis Hemofagocítica/genética , Fenotipo , Proteína de Unión al GTP cdc42/genética , Proteína de Unión al GTP cdc42/metabolismo , Alelos , Sustitución de Aminoácidos , Animales , Sitios de Unión , Línea Celular Tumoral , Niño , Femenino , Estudios de Asociación Genética , Genotipo , Humanos , Lactante , Masculino , Ratones , Modelos Moleculares , Conformación Molecular , Mutación , Unión Proteica , Proteína de Unión al GTP cdc42/químicaRESUMEN
RAF (rapidly accelerated fibrosarcoma) Ser/Thr kinases (ARAF, BRAF, and CRAF) link the RAS (rat sarcoma) protein family with the MAPK (mitogen-activated protein kinase) pathway and control cell growth, differentiation, development, aging, and tumorigenesis. Their activity is specifically modulated by protein-protein interactions, post-translational modifications, and conformational changes in specific spatiotemporal patterns via various upstream regulators, including the kinases, phosphatase, GTPases, and scaffold and modulator proteins. Dephosphorylation of Ser-259 (CRAF numbering) and dissociation of 14-3-3 release the RAF regulatory domains RAS-binding domain and cysteine-rich domain for interaction with RAS-GTP and membrane lipids. This, in turn, results in RAF phosphorylation at Ser-621 and 14-3-3 reassociation, followed by its dimerization and ultimately substrate binding and phosphorylation. This review focuses on structural understanding of how distinct binding partners trigger a cascade of molecular events that induces RAF kinase activation.
Asunto(s)
Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Proto-Oncogénicas A-raf/metabolismo , Proteínas Proto-Oncogénicas B-raf/metabolismo , Proteínas Proto-Oncogénicas c-raf/metabolismo , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Animales , Humanos , Proteínas Quinasas Activadas por Mitógenos/genética , Fosforilación , Unión Proteica , Proteínas Proto-Oncogénicas A-raf/genética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas c-raf/genéticaRESUMEN
Exome sequencing has markedly enhanced the discovery of genes implicated in Mendelian disorders, particularly for individuals in whom a known clinical entity could not be assigned. This has led to the recognition that phenotypic heterogeneity resulting from allelic mutations occurs more commonly than previously appreciated. Here, we report that missense variants in CDC42, a gene encoding a small GTPase functioning as an intracellular signaling node, underlie a clinically heterogeneous group of phenotypes characterized by variable growth dysregulation, facial dysmorphism, and neurodevelopmental, immunological, and hematological anomalies, including a phenotype resembling Noonan syndrome, a developmental disorder caused by dysregulated RAS signaling. In silico, in vitro, and in vivo analyses demonstrate that mutations variably perturb CDC42 function by altering the switch between the active and inactive states of the GTPase and/or affecting CDC42 interaction with effectors, and differentially disturb cellular and developmental processes. These findings reveal the remarkably variable impact that dominantly acting CDC42 mutations have on cell function and development, creating challenges in syndrome definition, and exemplify the importance of functional profiling for syndrome recognition and delineation.
Asunto(s)
Anomalías Múltiples/genética , Anomalías Craneofaciales/genética , Heterogeneidad Genética , Atrofia Muscular/genética , Mutación Missense , Trastornos del Neurodesarrollo/genética , Síndrome de Noonan/genética , Proteína de Unión al GTP cdc42/genética , Anomalías Múltiples/metabolismo , Anomalías Múltiples/patología , Adolescente , Adulto , Niño , Preescolar , Anomalías Craneofaciales/metabolismo , Anomalías Craneofaciales/patología , Femenino , Expresión Génica , Humanos , Lactante , Masculino , Modelos Moleculares , Atrofia Muscular/metabolismo , Atrofia Muscular/patología , Trastornos del Neurodesarrollo/metabolismo , Trastornos del Neurodesarrollo/patología , Síndrome de Noonan/metabolismo , Síndrome de Noonan/patología , Fenotipo , Estructura Secundaria de Proteína , Índice de Severidad de la Enfermedad , Proteína de Unión al GTP cdc42/química , Proteína de Unión al GTP cdc42/metabolismoRESUMEN
Thoracic radiotherapy causes damage of normal lung tissue, which limits the cumulative radiation dose and, hence, confines the anticancer efficacy of radiotherapy and impacts the quality of life of tumor patients. Ras-homologous (Rho) small GTPases regulate multiple stress responses and cell death. Therefore, we investigated whether pharmacological targeting of Rho signaling by the HMG-CoA-reductase inhibitor lovastatin influences ionizing radiation (IR)-induced toxicity in primary human lung fibroblasts, lung epithelial and lung microvascular endothelial cells in vitro and subchronic mouse lung tissue damage following hypo-fractionated irradiation (4x4 Gy). The statin improved the repair of radiation-induced DNA double-strand breaks (DSBs) in all cell types and, moreover, protected lung endothelial cells from IR-induced caspase-dependent apoptosis, likely involving p53-regulated mechanisms. Under the in vivo situation, treatment with lovastatin or the Rac1-specific small molecule inhibitor EHT1864 attenuated the IR-induced increase in breathing frequency and reduced the percentage of γH2AX and 53BP1-positive cells. This indicates that inhibition of Rac1 signaling lowers IR-induced residual DNA damage by promoting DNA repair. Moreover, lovastatin and EHT1864 protected lung tissue from IR-triggered apoptosis and mitigated the IR-stimulated increase in regenerative proliferation. Our data document beneficial anti-apoptotic and genoprotective effects of pharmacological targeting of Rho signaling following hypo-fractionated irradiation of lung cells in vitro and in vivo. Rac1-targeting drugs might be particular useful for supportive care in radiation oncology and, moreover, applicable to improve the anticancer efficacy of radiotherapy by widening the therapeutic window of thoracic radiation exposure.