RESUMEN

Lidamycin (LDM) has been confirmed to have a strong anti-pancreatic cancer effect and can affect the mitochondrial function of pancreatic cancer cells. Mitofusin-2 (Mfn2) is located in the outer membrane of mitochondria, and Mfn2 is currently believed to play a role in cancer inhibition in pancreatic cancer. In order to explore whether the anti-pancreatic cancer effect of LDM is related to Mfn2-mediated mitophagy, Bioinformatics and in vitro cell experiments are used for experimental research. The experimental results demonstrated that Mfn2 is correlated with mitochondrial autophagy in pancreatic cancer. Lidamycin can increase the expression of Mfn2 in pancreatic cancer and affect the process of EMT, affect the level of reactive oxygen species and mitochondrial membrane potential, and increase the expression of mitochondrial autophagy marker proteins BNIP3L and Beclin1. These results demonstrate that Mfn2 affects mitophagy in pancreatic cancer cells by regulating the expression of Mfn2.

Asunto(s)

GTP Fosfohidrolasas , Proteínas de la Membrana , Proteínas Mitocondriales , Mitofagia , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/genética , Mitofagia/efectos de los fármacos , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Línea Celular Tumoral , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Aminoglicósidos/farmacología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Beclina-1/metabolismo , Beclina-1/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Supresoras de Tumor

RESUMEN

BACKGROUND: The interplay between intrauterine and early postnatal environments has been associated with an increased risk of cardiovascular diseases in adulthood, including pulmonary arterial hypertension (PAH). While emerging evidence highlights the crucial role of mitochondrial pathology in PAH, the specific mechanisms driving fetal-originated PAH remain elusive. METHODS AND RESULTS: To elucidate the role of mitochondrial dynamics in the pathogenesis of fetal-originated PAH, we established a rat model of postnatal catch-up growth following intrauterine growth restriction (IUGR) to induce pulmonary arterial hypertension (PAH). RNA-seq analysis of pulmonary artery samples from the rats revealed dysregulated mitochondrial metabolic genes and pathways associated with increased pulmonary arterial pressure and pulmonary arterial remodeling in the RC group (postnatal catch-up growth following IUGR). In vitro experiments using pulmonary arterial smooth muscle cells (PASMCs) from the RC group demonstrated elevated proliferation, migration, and impaired mitochondrial functions. Notably, reduced expression of Mitofusion 2 (Mfn2), a mitochondrial outer membrane protein involved in mitochondrial fusion, was observed in the RC group. Reconstitution of Mfn2 resulted in enhanced mitochondrial fusion and improved mitochondrial functions in PASMCs of RC group, effectively reversing the Warburg effect. Importantly, Mfn2 reconstitution alleviated the PAH phenotype in the RC group rats. CONCLUSIONS: Imbalanced mitochondrial dynamics, characterized by reduced Mfn2 expression, plays a critical role in the development of fetal-originated PAH following postnatal catch-up growth after IUGR. Mfn2 emerges as a promising therapeutic strategy for managing IUGR-catch-up growth induced PAH.

Asunto(s)

Retardo del Crecimiento Fetal , GTP Fosfohidrolasas , Ratas Sprague-Dawley , Animales , Retardo del Crecimiento Fetal/metabolismo , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Ratas , Femenino , Hipertensión Arterial Pulmonar/metabolismo , Hipertensión Arterial Pulmonar/genética , Hipertensión Arterial Pulmonar/patología , Hipertensión Arterial Pulmonar/fisiopatología , Dinámicas Mitocondriales/fisiología , Masculino , Células Cultivadas , Embarazo , Miocitos del Músculo Liso/metabolismo , Miocitos del Músculo Liso/patología , Arteria Pulmonar/metabolismo , Arteria Pulmonar/patología , Arteria Pulmonar/fisiopatología , Modelos Animales de Enfermedad , Mitocondrias/metabolismo , Mitocondrias/patología , Animales Recién Nacidos , Proteínas Mitocondriales

RESUMEN

Multiple myeloma (MM) is a disease characterized by spatiotemporal heterogeneity of tumor clones. Different genetic aberrations can be observed simultaneously in tumor cells from different loci, and as the disease progresses, new subclones may appear. The role of liquid biopsy, which is based on the analysis of tumor DNA circulating in the blood plasma, continues to be explored in MM. Here, we present an analysis of the STR profiles and mutation status of the KRAS, NRAS, and BRAF genes, evaluated in plasma free circulating tumor DNA (ctDNA), CD138+ bone marrow cells, and plasmacytomas. The prospective single-center study included 97 patients, with a median age of 55 years. Of these, 94 had newly diagnosed symptomatic MM, and three had primary plasma cell leukemia. It should be noted that if mutations were detected only in ctDNA, "non-classical" codons were more often affected. A variety of adverse laboratory and clinical factors have been associated with the detection of rare KRAS or NRAS gene mutations in bone marrow or ctDNA, suggesting that these mutations may be factors of an unfavorable prognosis for MM. Liquid biopsy studies provide undeniable fundamental information about tumor heterogeneity and clonal evolution in MM. Moreover, we focus on using liquid biopsy to identify new high-risk factors for MM.

Asunto(s)

Mieloma Múltiple , Mutación , Proteínas Proto-Oncogénicas p21(ras) , Humanos , Mieloma Múltiple/genética , Mieloma Múltiple/patología , Persona de Mediana Edad , Femenino , Masculino , Anciano , Adulto , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas B-raf/genética , ADN Tumoral Circulante/genética , ADN Tumoral Circulante/sangre , GTP Fosfohidrolasas/genética , Sistema de Señalización de MAP Quinasas/genética , Proteínas de la Membrana/genética , Anciano de 80 o más Años , Estudios Prospectivos , Biopsia Líquida/métodos

RESUMEN

BACKGROUND/AIM: Despite therapeutic advancements, metastatic colorectal cancer is usually fatal, necessitating novel approaches based on the molecular pathogenesis to improve outcomes. Some colorectal cancers have no mutations in the extended RAS panel (KRAS, NRAS, BRAF) genes and represent a special subset, which deserves particular therapeutic considerations. MATERIALS AND METHODS: The genomic landscape of colorectal cancers from publicly available genomic series was interrogated, using the cBioportal platform. Colorectal cancer cohorts with cancers devoid of KRAS/NRAS or BRAF mutations were evaluated for the presence of mutations in the catalytic sub-unit alpha of kinase PI3K, encoded by the gene PIK3CA. RESULTS: PIK3CA mutations in the absence of KRAS/NRAS/BRAF mutations were observed in 3.7% to 7.6% of colorectal cancers in the different series examined. Patients with all four genes in wildtype configuration (quadruple wild type) represented 32.2% to 39.9% of cases in the different series examined. Compared with quadruple wild type cancers, triple (KRAS/NRAS/BRAF) wild type/PIK3CA mutated cancers had a higher prevalence of high TMB cases and additional mutations in colorectal cancer associated genes except for mutations in TP53. Mutations in genes encoding for epigenetic modifiers and the DNA damage response (DDR) were also more frequent in triple wild type/PIK3CA mutated cancers. The prognosis of the two groups was comparable. CONCLUSION: Colorectal cancers with PIK3CA mutations in the absence of KRAS/NRAS/BRAF mutations have frequently mutations in epigenetic modifiers and DDR response genes, which may provide opportunities for targeting. These mutations are present in a smaller subset of quadruple wild type cancers.

Asunto(s)

Fosfatidilinositol 3-Quinasa Clase I , Neoplasias Colorrectales , Epigénesis Genética , Mutación , Proteínas Proto-Oncogénicas B-raf , Proteínas Proto-Oncogénicas p21(ras) , Humanos , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Fosfatidilinositol 3-Quinasa Clase I/genética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Daño del ADN , Femenino , GTP Fosfohidrolasas/genética , Masculino , Proteínas de la Membrana/genética , Anciano , Persona de Mediana Edad

RESUMEN

Melanoma can pose a significant diagnostic challenge due to the high variability in histological morphology and expression of non-melanocytic immunomarkers. We present a case of a 47-year-old male with an aggressive mediastinal neoplasm and disseminated disease posing several diagnostic challenges. Multiple biopsies were submitted from different anatomic locations and during multiple time points showing an undifferentiated round cell tumor (URCT) with synovial sarcoma-like immunophenotype. SS18::SSX fusion was sought through NGS study for diagnostic confirmation. NGS results revealed NRAS and CDKN2A mutations and absence of fusions, resulting in a new review of the histologic material with a broader immunohistochemical panel, finding strong positivity to melanic antibodies. This case is an illustrative example of a malignant melanoma with small round cell morphology showing aberrant expression of CD99, BCL2, TLE1 and SS18-SSX antibodies exposing a potentially hazardous pitfall highlighting the importance of a wide differential diagnosis and the role of confirmational studies with molecular tests.

Asunto(s)

Biomarcadores de Tumor , Inmunofenotipificación , Neoplasias del Mediastino , Melanoma , Sarcoma Sinovial , Humanos , Masculino , Persona de Mediana Edad , Melanoma/patología , Melanoma/diagnóstico , Melanoma/inmunología , Melanoma/genética , Sarcoma Sinovial/patología , Sarcoma Sinovial/genética , Sarcoma Sinovial/diagnóstico , Sarcoma Sinovial/inmunología , Neoplasias del Mediastino/patología , Neoplasias del Mediastino/diagnóstico , Neoplasias del Mediastino/inmunología , Neoplasias del Mediastino/genética , Inmunofenotipificación/métodos , Biomarcadores de Tumor/análisis , Biomarcadores de Tumor/genética , Diagnóstico Diferencial , Proteínas de Fusión Oncogénica/genética , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , GTP Fosfohidrolasas/genética

RESUMEN

OBJECTIVE: To investigate the clinical characteristics and influence of co-mutated gene on acute myeloid leukemia patients (AML) with FMS-like tyrosine kinase-3 (FLT3) mutations. METHODS: A total of 273 FLT3+ AML patients were enrolled, and the co-mutation gene data of the patients were collected to further analyze the prognosis of the patients. FLT3 and other common mutations were quantified by PCR amplification products direct sequencing and second-generation sequencing (NGS). RESULTS: When patients were divided into FLT3- ITD +, FLT3- TKD +, FLT3- ITD ++TKD + and FLT3- ITD -+TKD - group according to the type of FLT3 mutations, it was found that the frequencies of TET2, GATA2, NRAS and ASXL1 mutation were significantly different among the 4 groups (all P < 0.05). When patients were divided into allelic ratio (AR) ≥0.5 and <0.5 group, it was found that the frequencies of FLT3- ITD +, FLT3 -ITD - +TKD -, NPM1, NRAS and C-kit were significantly different between the two groups (all P < 0.05). When patients were divided into normal and abnormal karyotype group, it was found that the frequencies of FLT3- ITD +, FLT3- TKD +, NPM1, GATA2 and C-kit were significantly different between the two groups (all P < 0.05). The median overall survival (OS) of AML patients with FLT3 -TKD + (including FLT3- ITD ++TKD +) was longer than that of patients with FLT3- ITD + alone (P < 0.05). The OS and relapse-free survival (RFS) of AML patients with FLT3++TET2+ were both shorter than those of patients with FLT3++TET2- (both P < 0.05). CONCLUSION: The mutation frequencies of co-mutated genes are correlated with subtypes of FLT3, karyotype and AR. AML patients with FLT3 -TKD + have longer OS than patients with FLT3- ITD + alone, and patients with co-mutation of TET2 have shorter median OS and RFS.

Asunto(s)

Dioxigenasas , GTP Fosfohidrolasas , Leucemia Mieloide Aguda , Mutación , Nucleofosmina , Tirosina Quinasa 3 Similar a fms , Humanos , Tirosina Quinasa 3 Similar a fms/genética , Leucemia Mieloide Aguda/genética , Pronóstico , GTP Fosfohidrolasas/genética , Proteínas de Unión al ADN/genética , Factor de Transcripción GATA2/genética , Proteínas Represoras/genética , Proteínas de la Membrana/genética , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-kit/genética

RESUMEN

RAS GTPases associate with the biological membrane where they function as molecular switches to regulate cell growth. Recent studies indicate that RAS proteins oligomerize on membranes, and disrupting these assemblies represents an alternative therapeutic strategy. However, conflicting reports on RAS assemblies, ranging in size from dimers to nanoclusters, have brought to the fore key questions regarding the stoichiometry and parameters that influence oligomerization. Here, we probe three isoforms of RAS [Kirsten Rat Sarcoma viral oncogene (KRAS), Harvey Rat Sarcoma viral oncogene (HRAS), and Neuroblastoma oncogene (NRAS)] directly from membranes using mass spectrometry. We show that KRAS on membranes in the inactive state (GDP-bound) is monomeric but forms dimers in the active state (GTP-bound). We demonstrate that the small molecule BI2852 can induce dimerization of KRAS, whereas the binding of effector proteins disrupts dimerization. We also show that RAS dimerization is dependent on lipid composition and reveal that oligomerization of NRAS is regulated by palmitoylation. By monitoring the intrinsic GTPase activity of RAS, we capture the emergence of a dimer containing either mixed nucleotides or GDP on membranes. We find that the interaction of RAS with the catalytic domain of Son of Sevenless (SOScat) is influenced by membrane composition. We also capture the activation and monomer to dimer conversion of KRAS by SOScat. These results not only reveal the stoichiometry of RAS assemblies on membranes but also uncover the impact of critical factors on oligomerization, encompassing regulation by nucleotides, lipids, and palmitoylation.

Asunto(s)

Membrana Celular , Multimerización de Proteína , Proteínas Proto-Oncogénicas p21(ras) , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/química , Humanos , Membrana Celular/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/química , GTP Fosfohidrolasas/genética , Lipoilación , Proteínas ras/metabolismo , Proteínas ras/química , Guanosina Trifosfato/metabolismo , Guanosina Difosfato/metabolismo

RESUMEN

The mechanisms of plant drought resistance are unclear but may involve membrane trafficking and metabolic reprogramming, including proline accumulation. Forward genetic screening using a proline dehydrogenase 1 (ProDH1) promoter:reporter identified a drought hypersensitive mutant with a single-amino acid substitution (P335L) in the nonphototrophic hypocotyl 3 (NPH3) domain of NPH3/root phototropism 2-like 5 (NRL5)/naked pins in Yucca 8 (NPY8). Further experiments found that NRL5 and other NPH3 domain proteins are guanosine triphosphatases (GTPases). NRL5, but not NRL5P335L, interacted with the RABE1c and RABH1b GTPases and the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) Vesicle-Associated Membrane Protein (VAMP)721/722. These proteins controlled NRL5 localization and connection to trafficking while also being genetically downstream of, and potentially regulated by, NRL5. These data demonstrate that NRL5-mediated restraint of proline catabolism is required for drought resistance and also reveal unexpected functions of the NPH3 domain such that the role of NPH3 domain proteins in signaling, trafficking, and cellular polarity can be critically reevaluated.

Asunto(s)

Sequías , Transporte de Proteínas , Arabidopsis/genética , Arabidopsis/metabolismo , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Dominios Proteicos , Estrés Fisiológico , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Mutación , Resistencia a la Sequía

RESUMEN

LSG1 is a conserved GTPase involved in ribosome assembly. It is required for the eviction of the nuclear export adapter NMD3 from the pre-60S subunit in the cytoplasm. In human cells, LSG1 has also been shown to interact with vesicle-associated membrane protein-associated proteins (VAPs) that are found primarily on the endoplasmic reticulum. VAPs interact with a large host of proteins which contain FFAT motifs (two phenylalanines (FF) in an acidic tract) and are involved in many cellular functions including membrane traffic and regulation of lipid transport. Here, we show that human LSG1 binds to VAPs via a noncanonical FFAT-like motif. Deletion of this motif specifically disrupts the localization of LSG1 to the ER, without perturbing LSG1-dependent recycling of NMD3 in cells or modulation of LSG1 GTPase activity in vitro.

Asunto(s)

Retículo Endoplásmico , GTP Fosfohidrolasas , Humanos , Secuencias de Aminoácidos , Retículo Endoplásmico/metabolismo , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Células HEK293 , Células HeLa , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Unión Proteica , Ribosomas/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Proteínas de Transporte Vesicular/genética

RESUMEN

Ferroptosis, an iron-dependent form of nonapoptotic cell death mediated by lipid peroxidation, has been implicated in the pathogenesis of multiple diseases. Subcellular organelles play pivotal roles in the regulation of ferroptosis, but the mechanisms underlying the contributions of the mitochondria remain poorly defined. Optic atrophy 1 (OPA1) is a mitochondrial dynamin-like GTPase that controls mitochondrial morphogenesis, fusion, and energetics. Here, we report that human and mouse cells lacking OPA1 are markedly resistant to ferroptosis. Reconstitution with OPA1 mutants demonstrates that ferroptosis sensitization requires the GTPase activity but is independent of OPA1-mediated mitochondrial fusion. Mechanistically, OPA1 confers susceptibility to ferroptosis by maintaining mitochondrial homeostasis and function, which contributes both to the generation of mitochondrial lipid reactive oxygen species (ROS) and suppression of an ATF4-mediated integrated stress response. Together, these results identify an OPA1-controlled mitochondrial axis of ferroptosis regulation and provide mechanistic insights for therapeutically manipulating this form of cell death in diseases.

Asunto(s)

Factor de Transcripción Activador 4 , Ferroptosis , GTP Fosfohidrolasas , Mitocondrias , Especies Reactivas de Oxígeno , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Ferroptosis/genética , Animales , Especies Reactivas de Oxígeno/metabolismo , Humanos , Mitocondrias/metabolismo , Mitocondrias/genética , Factor de Transcripción Activador 4/metabolismo , Factor de Transcripción Activador 4/genética , Dinámicas Mitocondriales , Ratones , Ratones Noqueados , Estrés Oxidativo , Transducción de Señal , Peroxidación de Lípido , Mutación

RESUMEN

AIM: There is a need for effective treatments for non-alcoholic fatty liver disease (NAFLD) that are economically inexpensive, and have few side effects. The present study aimed to investigate exercise training and silymarin on hepatocyte death factors in rats with liver damage. METHODS: Forty-nine male Wistar rats were assigned to seven groups: sedentary control, fatty liver control (DEX), fatty liver + high-intensity interval training (HIIT), fatty liver + HIIT + silymarin (HIIT + SILY), fatty liver + continuous training (CT), fatty liver + CT + silymarin (CT + SILY), and fatty liver + silymarin (SILY). A subcutaneous injection of dexamethasone for 7 days was used to induce fatty liver in rats. Masson's trichrome and hematoxylin-eosin staining were done to evaluate hepatic injury. The hepatocyte apoptosis was determined by TUNEL assay. Real-Time PCR was conducted to evaluate the gene expressions of caspase-9, adenosine monophosphate-activated protein kinase (AMPKα1), mitofusin 2 (Mfn2), and damage-regulated autophagy modulator (DRAM). Liver tissue changes and serum levels of liver enzymes were also evaluated. RESULTS: Liver apoptosis was decreased in the CT, HIIT, HIIT + SILY and CT + SILY groups compared to the DEX group. Both continuous and high-intensity training models produced beneficial alterations in liver morphology and hepatic injuries that were significant in exercise training + silymarin group. This impact was accompanied by increased AMPKα1 and DRAM gene expression and decreased caspase-9 and Mfn2 gene expression. Liver enzyme levels were high in the DEX group and treatment with silymarin significantly reduced it. CONCLUSION: Silymarin supplementation combined with interval or continuous training substantially improves DEX-induced hepatic steatosis and hepatocyte injury mostly through suppressing liver apoptosis and upregulating autophagy, which may provide a novel perspective for NAFLD treatment.

Asunto(s)

Apoptosis , Autofagia , Dexametasona , Hígado , Enfermedad del Hígado Graso no Alcohólico , Condicionamiento Físico Animal , Ratas Wistar , Silimarina , Animales , Silimarina/farmacología , Autofagia/efectos de los fármacos , Dexametasona/farmacología , Apoptosis/efectos de los fármacos , Masculino , Ratas , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Enfermedad del Hígado Graso no Alcohólico/terapia , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Enfermedad del Hígado Graso no Alcohólico/inducido químicamente , Enfermedad del Hígado Graso no Alcohólico/patología , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Hepatocitos/metabolismo , Hepatocitos/efectos de los fármacos , Proteínas Quinasas Activadas por AMP/metabolismo , Modelos Animales de Enfermedad , Caspasa 9/metabolismo , Caspasa 9/genética , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Proteínas Mitocondriales

RESUMEN

Charcot-Marie-Tooth type 2A (CMT2A) is a single-gene motor sensory neuropathy caused by Mfn2 mutation. It is generally believed that CMT2A involves mitochondrial fusion disruption. However, how Mfn2 mutation mediates the mitochondrial membrane fusion loss and its further pathogenic mechanisms remain unclear. Here, in vivo and in vitro mouse models harboring the Mfn2R364W, Mfn2G176S and Mfn2H165R mutations were constructed. Mitochondrial membrane fusion and fission proteins analysis showed that Mfn2R364W, Mfn2G176S, and Mfn2H165R/+ mutations maintain the expression of Mfn2, but promote Drp1 upregulation and Opa1 hydrolytic cleavage. In Mfn2H165R/H165R mutation, Mfn2, Drp1, and Opa1 all play a role in inducing mitochondrial fragmentation, and the mitochondrial aggregation is affected by Mfn2 loss. Further research into the pathogenesis of CMT2A showed these three mutations all induce mitochondria-mediated apoptosis, and mitochondrial oxidative phosphorylation damage. Overall, loss of overall fusion activity affects mitochondrial DNA (mtDNA) stability and causes mitochondrial loss and dysfunction, ultimately leading to CMT2A disease. Interestingly, the differences in the pathogenesis of CMT2A between Mfn2R364W, Mfn2G176S, Mfn2H165R/+ and Mfn2H165R/H165R mutations, including the distribution of Mfn2 and mitochondria, the expression of mitochondrial outer membrane-associated proteins (Bax, VDAC1 and AIF), and the enzyme activity of mitochondrial complex I, are related to the expression of Mfn2.

Asunto(s)

Apoptosis , Enfermedad de Charcot-Marie-Tooth , GTP Fosfohidrolasas , Mitocondrias , Mutación , Fosforilación Oxidativa , Enfermedad de Charcot-Marie-Tooth/genética , Enfermedad de Charcot-Marie-Tooth/metabolismo , Enfermedad de Charcot-Marie-Tooth/patología , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Animales , Mitocondrias/metabolismo , Mitocondrias/genética , Ratones , Apoptosis/genética , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Dinámicas Mitocondriales/genética , Humanos , Modelos Animales de Enfermedad

RESUMEN

Mitochondrial fusion and fission accompany adaptive responses to stress and altered metabolic demands. Inner membrane fusion and cristae morphogenesis depends on optic atrophy 1 (Opa1), which is expressed in different isoforms and is cleaved from a membrane-bound, long to a soluble, short form. Here, we have analyzed the physiological role of Opa1 isoforms and Opa1 processing by generating mouse lines expressing only one cleavable Opa1 isoform or a non-cleavable variant thereof. Our results show that expression of a single cleavable or non-cleavable Opa1 isoform preserves embryonic development and the health of adult mice. Opa1 processing is dispensable under metabolic and thermal stress but prolongs life span and protects against mitochondrial cardiomyopathy in OXPHOS-deficient Cox10-/- mice. Mechanistically, loss of Opa1 processing disturbs the balance between mitochondrial biogenesis and mitophagy, suppressing cardiac hypertrophic growth in Cox10-/- hearts. Our results highlight the critical regulatory role of Opa1 processing, mitochondrial dynamics, and metabolism for cardiac hypertrophy.

Asunto(s)

Cardiomiopatías , GTP Fosfohidrolasas , Animales , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Ratones , Cardiomiopatías/metabolismo , Cardiomiopatías/genética , Cardiomiopatías/patología , Dinámicas Mitocondriales , Mitofagia/genética , Ratones Noqueados , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/genética , Mitocondrias/metabolismo , Modelos Animales de Enfermedad , Desarrollo Embrionario/genética

RESUMEN

Mitochondrial functions can be regulated by membrane contact sites with the endoplasmic reticulum (ER). These mitochondria-ER contact sites (MERCs) are functionally heterogeneous and maintained by various tethers. Here, we found that REEP5, an ER tubule-shaping protein, interacts with Mitofusins 1/2 to mediate mitochondrial distribution throughout the cytosol by a new transport mechanism, mitochondrial "hitchhiking" with tubular ER on microtubules. REEP5 depletion led to reduced tethering and increased perinuclear localization of mitochondria. Conversely, increasing REEP5 expression facilitated mitochondrial distribution throughout the cytoplasm. Rapamycin-induced irreversible REEP5-MFN1/2 interaction led to mitochondrial hyperfusion, implying that the dynamic release of mitochondria from tethering is necessary for normal mitochondrial distribution and dynamics. Functionally, disruption of MFN2-REEP5 interaction dynamics by forced dimerization or silencing REEP5 modulated the production of mitochondrial reactive oxygen species (ROS). Overall, our results indicate that dynamic REEP5-MFN1/2 interaction mediates cytosolic distribution and connectivity of the mitochondrial network by "hitchhiking" and this process regulates mitochondrial ROS, which is vital for multiple physiological functions.

Asunto(s)

Retículo Endoplásmico , GTP Fosfohidrolasas , Mitocondrias , Especies Reactivas de Oxígeno , Retículo Endoplásmico/metabolismo , Mitocondrias/metabolismo , Humanos , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Especies Reactivas de Oxígeno/metabolismo , Células HeLa , Microtúbulos/metabolismo , Células HEK293 , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/genética , Unión Proteica , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Citosol/metabolismo , Dinámicas Mitocondriales

RESUMEN

RAS p.Q61R is the most prevalent hot-spot mutation in RAS and RAS-like mutated thyroid nodules. A few studies evaluated RAS p.Q61R by immunohistochemistry (RASQ61R-IHC). We performed a retrospective study of an institutional cohort of 150 patients with 217 thyroid lesions tested for RASQ61R-IHC, including clinical, cytologic and molecular data. RASQ61R-IHC was performed on 217 nodules (18% positive, 80% negative, and 2% equivocal). RAS p.Q61R was identified in 76% (n = 42), followed by RAS p.Q61K (15%; n = 8), and RAS p.G13R (5%; n = 3). NRAS p.Q61R isoform was the most common (44%; n = 15), followed by NRAS p.Q61K (17%; n = 6), KRAS p.Q61R (12%; n = 4), HRAS p.Q61R (12%; n = 4), HRAS p.Q61K (6%; n = 2), HRAS p.G13R (6%; n = 2), and NRAS p.G13R (3%; n = 1). RASQ61R-IHC was positive in 47% of noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP; 17/36), 22% of follicular thyroid carcinomas (FTC; 5/23), 10% of follicular thyroid adenomas (FTA; 4/40), and 8% of papillary thyroid carcinomas (PTC; 9/112). Of PTC studied (n = 112), invasive encapsulated follicular variant (IEFVPTC; n = 16) was the only subtype with positive RASQ61R-IHC (56%; 9/16). Overall, 31% of RAS-mutated nodules were carcinomas (17/54); and of the carcinomas, 94% (16/17) were low-risk per American Thyroid Associated (ATA) criteria, with only a single case (6%; 1/17) considered ATA high-risk. No RAS-mutated tumors recurred, and none showed local or distant metastasis (with a follow-up of 0-10 months). We found that most RAS-mutated tumors are low-grade neoplasms. RASQ61R-IHC is a quick, cost-effective, and reliable way to detect RAS p.Q61R in follicular-patterned thyroid neoplasia and, when malignant, guide surveillance.

Asunto(s)

Inmunohistoquímica , Nódulo Tiroideo , Humanos , Femenino , Masculino , Nódulo Tiroideo/patología , Nódulo Tiroideo/genética , Nódulo Tiroideo/metabolismo , Nódulo Tiroideo/diagnóstico , Persona de Mediana Edad , Adulto , Estudios Retrospectivos , Anciano , Neoplasias de la Tiroides/patología , Neoplasias de la Tiroides/metabolismo , Neoplasias de la Tiroides/genética , Neoplasias de la Tiroides/diagnóstico , Adulto Joven , Mutación , Anciano de 80 o más Años , Adolescente , Proteínas de la Membrana/genética , GTP Fosfohidrolasas/genética , Proteínas Proto-Oncogénicas p21(ras)

RESUMEN

RUNX1::RUNX1T1 (R::RT1) acute myeloid leukaemia (AML) remains a clinical challenge, and further research is required to model and understand leukaemogenesis. Previous zebrafish R::RT1 models were hampered by embryonic lethality and low penetrance of the malignant phenotype. Here, we overcome this by developing an adult zebrafish model in which the human R::RT1 isoform 9a is co-expressed with the frequently co-occurring oncogenic NRASG12D mutation in haematopoietic stem and progenitor cells (HSPCs), using the Runx1+23 enhancer. Approximately 50% of F0 9a+NRASG12D transgenic zebrafish developed signs of haematological disease between 5 and 14 months, with 27% exhibiting AML-like pathology: myeloid precursor expansion, erythrocyte reduction, kidney marrow hypercellularity and the presence of blasts. Moreover, only 9a+NRASG12D transplant recipients developed leukaemia with high rates of mortality within 40 days, inferring the presence of leukaemia stem cells. These leukaemic features were rare or not observed in animals expressing either the NRAS or 9a oncogenes alone, suggesting 9a and NRAS cooperation drives leukaemogenesis. This novel adult AML zebrafish model provides a powerful new tool for investigating the basis of R::RT1 - NRAS cooperativity with the potential to uncover new therapeutic targets.

Asunto(s)

Animales Modificados Genéticamente , Subunidad alfa 2 del Factor de Unión al Sitio Principal , Modelos Animales de Enfermedad , Mutación , Isoformas de Proteínas , Pez Cebra , Animales , Humanos , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Células Madre Hematopoyéticas/metabolismo , Leucemia Mieloide/genética , Leucemia Mieloide/etiología , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/etiología , Oncogenes , Isoformas de Proteínas/genética , Proteína 1 Compañera de Translocación de RUNX1/genética , Proteína 1 Compañera de Translocación de RUNX1/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismo

RESUMEN

Autosomal dominant optic atrophy (DOA) is a progressive form of blindness caused by degeneration of retinal ganglion cells and their axons, mainly caused by mutations in the OPA1 mitochondrial dynamin like GTPase (OPA1) gene. OPA1 encodes a dynamin-like GTPase present in the mitochondrial inner membrane. When associated with OPA1 mutations, DOA can present not only ocular symptoms but also multi-organ symptoms (DOA plus). DOA plus often results from point mutations in the GTPase domain, which are assumed to have dominant-negative effects. However, the presence of mutations in the GTPase domain does not always result in DOA plus. Therefore, an experimental system to distinguish between DOA and DOA plus is needed. In this study, we found that loss-of-function mutations of the dOPA1 gene in Drosophila can imitate the pathology of optic nerve degeneration observed in DOA. We successfully rescued this degeneration by expressing the human OPA1 (hOPA1) gene, indicating that hOPA1 is functionally interchangeable with dOPA1 in the fly system. However, mutations previously identified did not ameliorate the dOPA1 deficiency phenotype. By expressing both WT and DOA plus mutant hOPA1 forms in the optic nerve of dOPA1 mutants, we observed that DOA plus mutations suppressed the rescue, facilitating the distinction between loss-of-function and dominant-negative mutations in hOPA1. This fly model aids in distinguishing DOA from DOA plus and guides initial hOPA1 mutation treatment strategies.

Asunto(s)

Modelos Animales de Enfermedad , Proteínas de Drosophila , GTP Fosfohidrolasas , Atrofia Óptica Autosómica Dominante , Animales , Atrofia Óptica Autosómica Dominante/genética , Atrofia Óptica Autosómica Dominante/metabolismo , Atrofia Óptica Autosómica Dominante/patología , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Humanos , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Mutación , Drosophila/genética , Proteínas de la Membrana

RESUMEN

Alzheimer's disease (AD) is the most common neurodegenerative disorder, and amyloid beta oligomers (AßO), which are pathological markers of AD, are known to be highly toxic. AßO increase mitochondrial dysfunction, which is accompanied by a decrease in mitochondrial fusion. Although mitofusin (Mfn) 1 and Mfn2 are mitochondrial fusion proteins, Mfn2 is known to regulate endoplasmic reticulum (ER) function, as it is located in the ER. Several studies have shown that AßO exacerbates ER stress, however, the exact mechanism requires further elucidation. In this study, we used mouse neuroblastoma cells stably overexpressing the amyloid precursor protein (APP) with the Swedish mutation (N2a APPswe cells) to investigate the role of Mfn in ER stress. Our results revealed that  amyloid beta (Aß) caused cellular toxicity in N2a APPswe cells, upregulated ER stress-related proteins, and promoted ER expansion. The AßO-mediated ER stress was reduced when Mfn1 and Mfn2 were overexpressed. Moreover, Mfn1 and Mfn2 overexpressed resulted in reduced apoptosis of N2a APPswe cells. In conclusion, our results indicate that both Mfn1 and Mfn2 reduce ER stress and apoptosis. Our data provide a foundation for future studies on the roles of Mfn1 and Mfn2 in the molecular mechanisms underlying AßO-mediated ER stress and the pathogenesis of AD.

Asunto(s)

Péptidos beta-Amiloides , Apoptosis , Estrés del Retículo Endoplásmico , GTP Fosfohidrolasas , Animales , Humanos , Ratones , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Apoptosis/genética , Línea Celular Tumoral , Retículo Endoplásmico/metabolismo , Estrés del Retículo Endoplásmico/genética , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Mitocondrias/metabolismo

RESUMEN

Mitochondrial dysfunctions are detrimental to organ metabolism. The cornea, transparent outmost layer of the eye, is prone to environmental aggressions, such as UV light, and therefore dependent on adequate mitochondrial function. While several reports have linked corneal defects to mitochondrial dysfunction, the impact of OPA1 mutation, known to induce such dysfunction, has never been studied in this context. We used the mouse line carrying OPA1delTTAG mutation to investigate its impact on corneal biology. To our surprise, neither the tear film composition nor the corneal epithelial transcriptomic signature were altered upon OPA1 mutation. However, when analyzing the corneal innervation, we discovered an undersensitivity of the cornea upon the mutation, but an increased innervation volume at 3 months. Furthermore, the fibre identity changed with a decrease of the SP + axons. Finally, we demonstrated that the innervation regeneration was less efficient and less functional in OPA1+/- corneas. Altogether, our study describes the resilience of the corneal epithelial biology, reflecting the mitohormesis induced by the OPA1 mutation, and the adaptation of the corneal innervation to maintain its functionality despite its morphogenesis defects. These findings will participate to a better understanding of the mitochondrial dysfunction on peripheral innervation.

Asunto(s)

Córnea , GTP Fosfohidrolasas , Mitocondrias , Mutación , Animales , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Ratones , Córnea/inervación , Mitocondrias/metabolismo , Regeneración

RESUMEN

BACKGROUND: Mutations in KRAS and NRAS are associated with a lack of response to cetuximab and panitumumab, two biologics used for third-line therapy of metastatic colorectal cancer (mCRC). In British Columbia, Canada, eligibility for cetuximab or panitumumab was first based on single-gene KRAS testing. OncoPanel, a multi-gene next-generation sequencing panel with both KRAS and NRAS, was introduced in 2016. Our objective was to estimate the real-world cost-effectiveness of OncoPanel versus to single-gene KRAS testing to inform eligibility for cetuximab or panitumumab in mCRC. METHODS: Using population-based administrative health data, we identified a cohort of mCRC patients who had received a KRAS or OncoPanel test, and completed prior chemotherapy in 2010-2019. We matched KRAS- and OncoPanel-tested patients (1:1) using genetic matching to balance baseline covariates. Mean and incremental 3-year costs, survival, and quality-adjusted survival were estimated using inverse-probability-of-censoring weighting and bootstrapping. We conducted scenario-based sensitivity analysis for key costs and assumptions. FINDINGS: All OncoPanel-tested cases (n=371) were matched to a KRAS-tested comparator. In the KRAS and OncoPanel groups, respectively, 55·8 % and 41·2 % of patients were potentially eligible for cetuximab or panitumumab based on mutation status. Incremental cost and effectiveness of OncoPanel were $72 (95 % CI: -6387, 6107), -0·004 life-years (95 % CI: -0·119, 0·113), and -0·011 quality-adjusted life-years (95 % CI: -0·094, 0·075). Reductions in systemic therapy costs were offset by increased costs in other resources. Results were moderately sensitive to time horizon and changes in testing or treatment cost. INTERPRETATION: The use of OncoPanel resulted in more precise targeting of cetuximab and panitumumab, but there was no change in incremental cost or quality-adjusted survival. Understanding the balance of costs achieved in practice can provide insight into the effect of future changes in testing policy, test cost, treatment eligibility, or drug prices in this setting.

Asunto(s)

Cetuximab , Neoplasias Colorrectales , Análisis Costo-Beneficio , Panitumumab , Humanos , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Masculino , Femenino , Cetuximab/uso terapéutico , Cetuximab/economía , Persona de Mediana Edad , Anciano , Panitumumab/uso terapéutico , Proteínas Proto-Oncogénicas p21(ras)/genética , Pruebas Genéticas/economía , Años de Vida Ajustados por Calidad de Vida , Secuenciación de Nucleótidos de Alto Rendimiento , Colombia Británica , Metástasis de la Neoplasia , GTP Fosfohidrolasas/genética , Mutación , Proteínas de la Membrana/genética