RESUMEN

OBJECTIVE: The aim of this study was to evaluate mitofusin-2 levels and fetal Doppler ultrasonography effects in patients with severe preeclampsia. METHODS: This single-center case-control study was conducted in the gynecology service of the university hospital in Van. A total of 90 pregnant women aged 18-40 years were included in the study. Of these, 30 are normal, 30 have mild preeclampsia, and 30 are pregnant with severe preeclampsia. In this study, especially in severe preeclampsia patients, serum mitofusin-2 levels and important fetal Doppler flows such as uterine arterial pressure, umbilical arterial pressure, and 1st and 5th minute Apgar scores, birth weight, and the relationship between postnatal outcomes such as week of birth and the number of patients in the neonatal intensive care unit were investigated. RESULTS: There was a significant difference between the three groups in terms of mitofusin-2 levels, which was the highest in the group (p<0.05). Maternal serum mitofusin-2 levels were positively correlated with uterine arterial pressure (r=0.543, p=0.007), umbilical arterial pressure (r=0.238, p=0.008), diastolic blood pressure, and systolic blood pressure (p<0.001). Receiver operating characteristic curve of mitofusin-2 in predicting preeclampsia is as follows: optimal cutoff 1.6 ng/mL; area under the curve: 0.861; 95%CI: 0.786-0.917; sensitivity: 83.9%; and specificity: 70.0%, (p≤0.001). A one-unit increase in mitofusin-2 resulted in a statistically significant 4.21-fold increase in preeclampsia risk. CONCLUSION: This study recommends the use of mitofusin-2 together with fetal Doppler ultrasound findings as a reliable indicator of preeclampsia severity.

Asunto(s)

Preeclampsia , Resultado del Embarazo , Índice de Severidad de la Enfermedad , Ultrasonografía Prenatal , Humanos , Femenino , Embarazo , Preeclampsia/sangre , Preeclampsia/diagnóstico por imagen , Adulto , Estudios de Casos y Controles , Adulto Joven , Adolescente , GTP Fosfohidrolasas/sangre , Proteínas Mitocondriales/sangre , Biomarcadores/sangre , Valor Predictivo de las Pruebas , Puntaje de Apgar , Ultrasonografía Doppler , Curva ROC , Arterias Umbilicales/diagnóstico por imagen

RESUMEN

Mitofusins (Mfn1 and Mfn2) are the mitochondrial outer-membrane fusion proteins in mammals and belong to the dynamin superfamily of multidomain GTPases. Recent structural studies of truncated variants lacking alpha helical transmembrane domains suggested that Mfns dimerize to promote the approximation and the fusion of the mitochondrial outer membranes upon the hydrolysis of guanine 5'-triphosphate disodium salt (GTP). However, next to the presence of GTP, the fusion activity seems to require multiple regulatory factors that control the dynamics and kinetics of mitochondrial fusion through the formation of Mfn1-Mfn2 heterodimers. Here, we purified and reconstituted the full-length murine Mfn2 protein into giant unilamellar vesicles (GUVs) with different lipid compositions. The incubation with GTP resulted in the fusion of Mfn2-GUVs. High-speed video-microscopy showed that the Mfn2-dependent membrane fusion pathway progressed through a zipper mechanism where the formation and growth of an adhesion patch eventually led to the formation of a membrane opening at the rim of the septum. The presence of physiological concentration (up to 30 mol%) of dioleoyl-phosphatidylethanolamine (DOPE) was shown to be a requisite to observe GTP-induced Mfn2-dependent fusion. Our observations show that Mfn2 alone can promote the fusion of micron-sized DOPE-enriched vesicles without the requirement of regulatory cofactors, such as membrane curvature, or the assistance of other proteins.

Asunto(s)

GTP Fosfohidrolasas , Fusión de Membrana , Animales , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Ratones , Fusión de Membrana/fisiología , Liposomas Unilamelares/metabolismo , Liposomas Unilamelares/química , Guanosina Trifosfato/metabolismo , Fosfatidiletanolaminas/metabolismo , Membranas Mitocondriales/metabolismo , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Mitocondrias/metabolismo

RESUMEN

Methylphenidate (MPH) is a central nervous system stimulant drug and a first order prescription in the treatment of Attention Deficit Hyperactivity Disorder (ADHD). Although MPH biochemistry in neurodevelopment is not completely understood, studies showed it alters energy metabolism in rat brains. ADHD prevalence during neurodevelopment is related to males and the investigation has been mainly done in these subjects, therefore, little is known about MPH action in females and, consequently, about sexual dimorphism. In the present study we evaluated markers of mitochondrial dynamics (DRP1 and MFN2, fission and fusion, respectively), biogenesis (mtTFA) and bioenergetics (respiratory chain complexes) in prefrontal cortex of male and female juvenile rats submitted to exposure to MPH to better understand MPH effect during postnatal neurodevelopment. ATP and oxidative stress levels were also evaluated. Wistar rats received intraperitoneal injection of MPH (2.0 mg/kg) or control (saline), once a day, from 15th to 45th day of age. Results showed that MPH increased DRP1 and decreased MFN2, as well as increased mtTFA in prefrontal cortex of male rats. In female, MPH decreased NRF1 and increased Parkin, which are mitochondrial regulatory proteins. Respiratory chain complexes (complex I, SDH, complexes III and IV), ATP production and oxidative stress parameters were altered and shown to be sex-dependent. Taken together, results suggest that chronic MPH exposure at an early age in healthy animals changes mitochondrial dynamics, biogenesis and bioenergetics differently depending on the sex of the subjects.

Asunto(s)

Estimulantes del Sistema Nervioso Central , Dinaminas , Metabolismo Energético , Metilfenidato , Dinámicas Mitocondriales , Estrés Oxidativo , Corteza Prefrontal , Ratas Wistar , Animales , Corteza Prefrontal/efectos de los fármacos , Corteza Prefrontal/metabolismo , Metilfenidato/farmacología , Masculino , Dinámicas Mitocondriales/efectos de los fármacos , Femenino , Estimulantes del Sistema Nervioso Central/farmacología , Metabolismo Energético/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Dinaminas/metabolismo , Ratas , Caracteres Sexuales , Adenosina Trifosfato/metabolismo , GTP Fosfohidrolasas/metabolismo , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Proteínas Mitocondriales , Ubiquitina-Proteína Ligasas

RESUMEN

PURPOSE: The advent of circulating tumor DNA (ctDNA) technology has provided a convenient and noninvasive means to continuously monitor cancer genomic data, facilitating personalized cancer treatment. This study aimed to evaluate the supplementary benefits of plasma ctDNA alongside traditional tissue-based next-generation sequencing (NGS) in identifying targetable mutations and tumor mutational burden (TMB) in colorectal cancers (CRC). METHODS: Our study involved 76 CRC patients, collecting both tissue and plasma samples for NGS. We assessed the concordance of gene mutational status between ctDNA and tissue, focusing on actionable genes such as KRAS, NRAS, PIK3CA, BRAF, and ERBB2. Logistic regression analysis was used to explore variables associated with discordance and positive mutation rates. RESULTS: In total, 26 cancer-related genes were identified. The most common variants in tumor tissues and plasma samples were in APC (57.9% vs 19.7%), TP53 (55.3% vs 22.4%) and KRAS (47.4% vs 43.4%). Tissue and ctDNA showed an overall concordance of 73.53% in detecting actionable gene mutations. Notably, plasma ctDNA improved detection for certain genes and gene pools. Variables significantly associated with discordance included gender and peritoneal metastases. TMB analysis revealed a higher detection rate in tissues compared to plasma, but combining both increased detection. CONCLUSIONS: Our study highlights the importance of analyzing both tissue and plasma for detecting actionable mutations in CRC, with plasma ctDNA offering added value. Discordance is associated with gender and peritoneal metastases, and TMB analysis can benefit from a combination of tissue and plasma data. This approach provides valuable insights for personalized CRC treatment.

Asunto(s)

ADN Tumoral Circulante , Neoplasias Colorrectales , Secuenciación de Nucleótidos de Alto Rendimiento , Mutación , Humanos , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/sangre , Neoplasias Colorrectales/patología , Masculino , Femenino , ADN Tumoral Circulante/sangre , ADN Tumoral Circulante/genética , Persona de Mediana Edad , Anciano , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Proteínas Proto-Oncogénicas B-raf/genética , GTP Fosfohidrolasas/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Fosfatidilinositol 3-Quinasa Clase I/genética , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/sangre , Adulto , Anciano de 80 o más Años , Proteína p53 Supresora de Tumor/genética , Receptor ErbB-2/genética , Proteína de la Poliposis Adenomatosa del Colon/genética , Proteínas de la Membrana/genética , Proteínas de la Membrana/sangre

RESUMEN

PURPOSE: RAS (KRAS/NRAS) mutational status on a tumor biopsy is mandatory to guide the best treatment in metastatic colorectal cancer (mCRC). Determining the RAS mutational status by tumor-tissue biopsy is essential in guiding the optimal treatment decision for mCRC. RAS mutations are negative predictive factors for the use of EGFR monoclonal antibodies. Cell-free DNA (cfDNA) analysis enables minimally invasive monitoring of tumor evolution. METHODS/PATIENTS: PERSEIDA was an observational, prospective study assessing cfDNA RAS, BRAF and EGFR mutations (using Idylla™) in first-line mCRC, RAS wild-type (baseline tumor-tissue biopsy) patients (cohort 2). Plasma samples were collected before first-line treatment, after 20 ± 2 weeks, and at disease progression. RESULTS: 117 patients were included (103 received panitumumab + chemotherapy as first-line treatment). At baseline, 7 (6.8%) patients had RAS mutations, 4 (3.9%) BRAF mutations and no EGFR mutations were detected (cfDNA, panitumumab + chemotherapy subpopulation [panitumumab + Ch]). The baseline RAS mutational status concordance between tissue and liquid biopsies was 94.0% (93.2%, panitumumab + Ch). At 20 weeks, only one patient in the study (included in the panitumumab + Ch) had an emerging cfDNA RAS mutation. No emerging BRAF or EGFR mutations were reported. At disease progression, 6 patients had emergent mutations not present at baseline (RAS conversion rate: 13.3% [6/45]; 15.0% [6/40], panitumumab + Ch). CONCLUSIONS: The concordance rate between liquid and solid biopsies at baseline was very high, as previously reported, while our results suggest a considerable emergence of RAS mutations during disease progression. Thus, the dynamics of the genomic landscape in ctDNA may provide relevant information for the management of mCRC patients.

Asunto(s)

Ácidos Nucleicos Libres de Células , Neoplasias Colorrectales , Mutación , Panitumumab , Proteínas Proto-Oncogénicas B-raf , Humanos , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/sangre , Femenino , Masculino , Estudios Prospectivos , Anciano , Persona de Mediana Edad , Ácidos Nucleicos Libres de Células/genética , Ácidos Nucleicos Libres de Células/sangre , Proteínas Proto-Oncogénicas B-raf/genética , Panitumumab/uso terapéutico , Proteínas Proto-Oncogénicas p21(ras)/genética , Receptores ErbB/genética , Adulto , Anciano de 80 o más Años , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , GTP Fosfohidrolasas/genética , Progresión de la Enfermedad , Proteínas de la Membrana/genética

RESUMEN

The essential yeast protein GPN-loop GTPase 1 (Npa3) plays a critical role in RNA polymerase II (RNAPII) assembly and subsequent nuclear import. We previously identified a synthetic lethal interaction between a mutant lacking the carboxy-terminal 106-amino acid tail of Npa3 (npa3ΔC) and a bud27Δ mutant. As the prefoldin-like Bud27 protein participates in ribosome biogenesis and translation, we hypothesized that Npa3 may also regulate these biological processes. We investigated this proposal by using Saccharomyces cerevisiae strains episomally expressing either wild-type Npa3 or hypomorphic mutants (Npa3ΔC, Npa3K16R, and Npa3G70A). The Npa3ΔC mutant fully supports RNAPII nuclear localization and activity. However, the Npa3K16R and Npa3G70A mutants only partially mediate RNAPII nuclear targeting and exhibit a higher reduction in Npa3 function. Cell proliferation in these strains displayed an increased sensitivity to protein synthesis inhibitors hygromycin B and geneticin/G418 (npa3G70A > npa3K16R > npa3ΔC > NPA3 cells) but not to transcriptional elongation inhibitors 6-azauracil, mycophenolic acid or 1,10-phenanthroline. In all three mutant strains, the increase in sensitivity to both aminoglycoside antibiotics was totally rescued by expressing NPA3. Protein synthesis, visualized by quantifying puromycin incorporation into nascent-polypeptide chains, was markedly more sensitive to hygromycin B inhibition in npa3ΔC, npa3K16R, and npa3G70A than NPA3 cells. Notably, high-copy expression of the TIF11 gene, that encodes the eukaryotic translation initiation factor 1A (eIF1A) protein, completely suppressed both phenotypes (of reduced basal cell growth and increased sensitivity to hygromycin B) in npa3ΔC cells but not npa3K16R or npa3G70A cells. We conclude that Npa3 plays a critical RNAPII-independent and previously unrecognized role in translation initiation.

Asunto(s)

Factor 1 Eucariótico de Iniciación , Higromicina B , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Núcleo Celular/metabolismo , Núcleo Celular/genética , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Higromicina B/farmacología , Biosíntesis de Proteínas/efectos de los fármacos , Inhibidores de la Síntesis de la Proteína/farmacología , ARN Polimerasa II/genética , ARN Polimerasa II/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/crecimiento & desarrollo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Unión al GTP Monoméricas/genética , Proteínas de Unión al GTP Monoméricas/metabolismo

RESUMEN

Mycobacterium tuberculosis is composed of a cumbersome signaling and protein network which partakes in bacterial survival and augments its pathogenesis. Mycobacterial PhoH2 (Mt-PhoH2) is a signaling element and a predictive phosphate starvation protein that works in an ATP-dependent manner. Here, we elaborated the characterization of Mt-PhoH2 through biophysical, biochemical, and computational methods. In addition to its intrinsic ATPase activity, the biochemical experiments revealed its GTPase activity and both activities are metal ion dependent. Magnesium, manganese, copper, iron, nickel, zinc, cesium, calcium, and lithium were examined for their effect on activity, and the optimum activity was found with 10 mM of Mg2+ ions. The kinetic parameters of 3 µM Mt-PhoH2 were observed as Km 4.873 ± 0.44 µM, Vmax 12.3817 ± 0.084 µM/min/mg, Kcat 0.0075 ± 0.00005 s-1, and Kcat/Km 0.0015 ± 0.000001 µM-1 s-1 with GTP. In the case of GTP as a substrate, a 20% decrease in enzymatic activity and a 50% increase in binding affinity of Mt-PhoH2 were observed. The substrates ADP and GDP inhibit the ATPase and GTPase activity of Mt-PhoH2. CD spectroscopy showed the dominance of alpha helix in the secondary structure of Mt-PhoH2, and this structural pattern was altered upon addition of ATP and GTP. In silico inhibitor screening revealed ML141 and NAV_2729 as two potential inhibitors of the catalytic activity of Mt-PhoH2. Mt-PhoH2 is essential for mycobacterial growth as its knockdown strain showed a decreased growth effect. Overall, the present article emphasizes the factors essential for the proper functioning of Mt-PhoH2 which is a participant in the toxin-antitoxin machinery and may also play an important role in phosphate starvation.

Asunto(s)

Proteínas Bacterianas , Mycobacterium tuberculosis , Mycobacterium tuberculosis/enzimología , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/efectos de los fármacos , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/química , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/metabolismo , Cinética , Adenosina Trifosfatasas/metabolismo , Adenosina Trifosfatasas/química , Adenosina Trifosfatasas/antagonistas & inhibidores , Adenosina Trifosfatasas/genética , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/química

RESUMEN

INTRODUCTION: Molecular alterations in follicular cells in the BRAF or NRAS genes have been reported to be associated with the process of carcinogenesis. Our aim was to determine the mutational frequency of BRAF and NRAS in fine-needle aspiration (FNA) specimens in our population. METHODS: The mutational status of BRAF (codon 600) and NRAS (codon 61) was analysed by qPCR in 193 FNA specimens from suspicious nodules and compared with pathological data of 115 patients. RESULTS: BRAF mutation was identified in 40 samples (74.1%) of FNAs classified as Bethesda VI (n = 54). In samples histologically diagnosed as classic papillary thyroid carcinoma (cPTC, n = 47), mutation was observed in 70% of cases, while in other subtypes the prevalence was lower (p = 0.013). In FNA specimens of follicular lesions (n = 36), positivity for NRAS was found in 50% of the follicular carcinomas (FTCs), but only in 6.7% of adenomas. Finally, there was a significant correlation between BRAF and PTC with lymph-node metastasis (p = 0.014) and increased relative risk of recurrence based on the Argentine Intersociety Consensus (RR = 6.77, p = 0.022). No significant differences were found between BRAF mutation and other features of aggressiveness in PTC. CONCLUSION: BRAF and NRAS mutations are observed in a significant number of PTCs and FTCs, in our population. There is a significant correlation between BRAF mutation and lymph-node metastasis.

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Introducción: Se ha descrito que alteraciones moleculares de las células foliculares tiroideas en el gen BRAF o en NRAS están asociadas con el proceso de carcinogénesis. Nuestro objetivo fue conocer la frecuencia mutacional de BRAF y NRAS a partir de muestras de punción aspirativa con aguja fina (PAAF) en nuestra población. Métodos: Se analizó por qPCR el estado mutacional de BRAF (codón 600) y NRAS (codón 61) de 193 muestras obtenidas por PAAF de nódulos sospechosos y se comparó con los datos de la anatomía patológica de 115 pacientes. Resultados: La mutación BRAF se identificó en 40 muestras (74.1%) de las punciones categorizadas como Bethesda VI (n = 54). En las muestras que se correspondieron con carcinoma papilar de tiroides (CPT) variante clásica por histología (n = 47), el 70% presentó la mutación, mientras que en los otros subtipos la prevalencia fue más baja (p = 0.013). En muestras de lesión folicular (n = 36), el 50% de los carcinomas foliculares resultaron positivos para NRAS pero solo el 6.7% de los adenomas presentaron esta variación. La presencia de mutación BRAF y CPT se asociaron con metástasis en los ganglios linfáticos (p = 0.014) y mayor riesgo relativo de recurrencia según el Consenso Argentino Intersocietario (RR = 6.77, p = 0.022). No hubo diferencias significativas entre la mutación de BRAF y otras características de agresividad en CPT. Conclusión: La mutación de BRAF y NRAS se observa en un número significativo de CPT y carcinoma folicular, respectivamente, en nuestra población. La mutación BRAF se correlaciona significativamente con metástasis en los ganglios linfáticos.

Asunto(s)

Carcinoma Papilar , Neoplasias de la Tiroides , Humanos , Proteínas Proto-Oncogénicas B-raf/genética , Metástasis Linfática , Argentina , Análisis Mutacional de ADN , Neoplasias de la Tiroides/patología , Mutación , Codón , Proteínas de la Membrana/genética , GTP Fosfohidrolasas/genética

RESUMEN

Development of the mammalian neocortex requires proper inside-out migration of developing cortical neurons from the germinal ventricular zone toward the cortical plate. The mechanics of this migration requires precise coordination of different cellular phenomena including cytoskeleton dynamics, membrane trafficking, and cell adhesion. The small GTPases play a central role in all these events. The small GTPase Rab21 regulates migration and neurite growth in developing neurons. Moreover, regulators and effectors of Rab21 have been implicated in brain pathologies with cortical malformations, suggesting a key function for the Rab21 signaling pathway in cortical development. Mechanistically, it has been posited that Rab21 influences cell migration by controlling the trafficking of endocytic vesicles containing adhesion molecules. However, direct evidence of the participation of Rab21 or its mechanism of action in the regulation of cortical migration is still incomplete. In this study, we demonstrate that Rab21 plays a critical role in the differentiation and migration of pyramidal neurons by regulating the levels of the amyloid precursor protein on the neuronal cell surface. Rab21 loss of function increased the levels of membrane-exposed APP, resulting in impaired cortical neuronal differentiation and migration. These findings further our understanding of the processes governing the development of the cerebral cortex and shed light onto the molecular mechanisms behind cortical development disorders derived from the malfunctioning of Rab21 signaling effectors.

Asunto(s)

GTP Fosfohidrolasas , Neocórtex , Animales , GTP Fosfohidrolasas/metabolismo , Corteza Cerebral/metabolismo , Neuronas/metabolismo , Neocórtex/metabolismo , Movimiento Celular/fisiología , Precursor de Proteína beta-Amiloide/metabolismo , Mamíferos/metabolismo

RESUMEN

In filamentous fungi, the hypha orientation is essential for polarized growth and morphogenesis. The ability to re-orient tip growth in response to environmental cues is critical for the colony survival. Therefore, hyphal tip orientation and tip extension are distinct mechanisms that operate in parallel during filamentous growth. In yeast, the axial growth orientation requires a pathway regulated by Rsr1p/Bud1p, a Ras-like GTPase protein, which determines the axial budding pattern. However, in filamentous fungi the function of the Rsr1/Bud1p gene (krev-1 homolog) has not been completely characterized. In this work, we characterized the phenotype of a homokaryon mutant Bud1p orthologous in Neurospora crassa (△bud-1) and tagged BUD-1 with the green fluorescent protein (GFP) to determine its localization and cell dynamics under confocal microscopy. During spore germination BUD-1 was localized at specific points along the plasma membrane and during germ tube emergence it was located at the tip of the germ tubes. In mature hyphae BUD-1 continued to be located at the cell tip and was also present at sites of branch emergence and at the time of septum formation. The △bud-1 mutant showed a delayed germination, and the orientation of hyphae was somewhat disrupted. Also, the hypha diameter was reduced approximately 37 % with respect to the wild type. The lack of BUD-1 affected the Spitzenkörper (Spk) formation, trajectory, the localization of polarisome components BNI-1 and SPA-2, and the actin cytoskeleton polarization. The results presented here suggest that BUD-1 participates in the establishment of a new polarity axis. It may also mediate the delivery of secretory vesicles for the efficient construction of new plasma membrane and cell wall.

Asunto(s)

Neurospora crassa , Esporas Fúngicas/genética , Esporas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , GTP Fosfohidrolasas/metabolismo , Hifa

RESUMEN

Previous studies have shown that peripheral nerve injury can lead to abnormal dendritic spine remodeling in spinal dorsal horn neurons. Inhibition of abnormal dendritic spine remodeling can relieve neuropathic pain. Electroacupuncture (EA) has a beneficial effect on the treatment of neuropathic pain, but the specific mechanism remains unclear. Evidence has shown that slit-robo GTPase activating protein 3 (srGAP3) and Rho GTPase (Rac1) play very important roles in dendritic spine remodeling. Here, we used srGAP3 siRNA and Rac1 activator CN04 to confirm the relationship between SrGAP3 and Rac1 and their roles in improving neuropathic pain with EA. Spinal nerve ligation (SNL) was used as the experimental model, and thermal withdrawal latency (TWL), mechanical withdrawal threshold (MWT), Western blotting, immunohistochemistry and Golgi-Cox staining were used to examine changes in behavioral performance, protein expression and dendritic spines. More dendritic spines and higher expression levels of srGAP3 were found in the initial phase of neuropathic pain. During the maintenance phase, dendritic spines were more mature, which was consistent with lower expression levels of srGAP3 and higher expression levels of Rac1-GTP. EA during the maintenance phase reduced the density and maturity of dendritic spines of rats with SNL, increased the levels of srGAP3 and reduced the levels of Rac1-GTP, while srGAP3 siRNA and CN04 reversed the therapeutic effects of EA. These results suggest that dendritic spines have different manifestations in different stages of neuropathic pain and that EA may inhibit the abnormal dendritic spine remodeling by regulating the srGAP3/Rac1 signaling pathway to alleviate neuropathic pain.

Asunto(s)

Electroacupuntura , Neuralgia , Animales , Ratas , Espinas Dendríticas/metabolismo , GTP Fosfohidrolasas/metabolismo , Guanosina Trifosfato/metabolismo , Neuralgia/metabolismo , Neuralgia/terapia , Proteína de Unión al GTP rac1/metabolismo , Ratas Sprague-Dawley , Transducción de Señal , Nervios Espinales/metabolismo

RESUMEN

The metabolic plasticity of mitochondria ensures cell development, differentiation, and survival. The peptidase OMA1 regulates mitochondrial morphology via OPA1 and stress signaling via DELE1 and orchestrates tumorigenesis and cell survival in a cell- and tissue-specific manner. Here, we use unbiased systems-based approaches to show that OMA1-dependent cell survival depends on metabolic cues. A metabolism-focused CRISPR screen combined with an integrated analysis of human gene expression data found that OMA1 protects against DNA damage. Nucleotide deficiencies induced by chemotherapeutic agents promote p53-dependent apoptosis of cells lacking OMA1. The protective effect of OMA1 does not depend on OMA1 activation or OMA1-mediated OPA1 and DELE1 processing. OMA1-deficient cells show reduced glycolysis and accumulate oxidative phosphorylation (OXPHOS) proteins upon DNA damage. OXPHOS inhibition restores glycolysis and confers resistance against DNA damage. Thus, OMA1 dictates the balance between cell death and survival through the control of glucose metabolism, shedding light on its role in cancerogenesis.

Asunto(s)

Metaloendopeptidasas , Péptido Hidrolasas , Humanos , ADN/metabolismo , GTP Fosfohidrolasas/metabolismo , Metaloendopeptidasas/metabolismo , Mitocondrias/metabolismo , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Fosforilación Oxidativa , Péptido Hidrolasas/metabolismo

RESUMEN

BACKGROUND AND OBJECTIVES: KRAS, NRAS, BRAF mutations and microsatellite instability (MSI) can be associated with Colorectal Cancer (CRC) development. MATERIAL AND METHODS: We evaluated 828 medical records of CRC patients from a school hospital from January/2016 to December/2020. Variables such as age, gender, ethnicity, literacy level, smoking, alcoholism, primary anatomical site, tumor staging, presence of BRAFV600E, KRAS, NRAS mutations and MSI , survival and metastasis were identified. The statistical analyses were performed (p < 0.05 was considered significant). RESULTS: There was a predominance of males (51.93%), whites (90.70%), low education (72.34%), smokers (73.79%), and non-alcoholics (79.10%). Rectum was the most affected site (42.14%), advanced tumor stage was most prevalent (62.07%), and metastasis occurred in (64.61%). Of the enrolled patients; 204 were investigated for BRAF mutation and detected in (2.94%); 216 for KRAS gene and detected in (26.08%); 210 for NRAS gene, and detected in (25.36%); 370 for MSI and detected in (44.68%). A significant association of CRC with NRAS mutation and alcohol habit (p = 0.043) was observed. The presence of MSI was associated with primary site proximal colon (p < 0.000), distal colon (p = 0.001) and rectum (p = 0.010). CONCLUSION: Patients with CRC are male, over 64 years old, white, with low education, smokers and non-alcoholics. The most affected primary site is rectum in advanced stage with metastasis. CRC is associated with NRAS mutation and alcohol habit, there is increased risk for primary site of proximal colon and MSI; decreased risk for distal colon and rectum in the presence of MSI.

Asunto(s)

Neoplasias Colorrectales , Proteínas Proto-Oncogénicas B-raf , Humanos , Masculino , Persona de Mediana Edad , Femenino , Proteínas Proto-Oncogénicas B-raf/genética , Inestabilidad de Microsatélites , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Genes ras , Mutación , Proteínas de la Membrana/genética , GTP Fosfohidrolasas/genética

RESUMEN

Inner mitochondrial membrane fusion and cristae shape depend on optic atrophy protein 1, OPA1. Mutations in OPA1 lead to autosomal dominant optic atrophy (ADOA), an important cause of inherited blindness. The Guanosin Triphosphatase (GTPase) and GTPase effector domains (GEDs) of OPA1 are essential for mitochondrial fusion; yet, their specific roles remain elusive. Intriguingly, patients carrying OPA1 GTPase mutations have a higher risk of developing more severe multisystemic symptoms in addition to optic atrophy, suggesting pathogenic contributions for the GTPase and GED domains, respectively. We studied OPA1 GTPase and GED mutations to understand their domain-specific contribution to protein function by analyzing patient-derived cells and gain-of-function paradigms. Mitochondria from OPA1 GTPase (c.870+5G>A and c.889C>T) and GED (c.2713C>T and c.2818+5G>A) mutants display distinct aberrant cristae ultrastructure. While all OPA1 mutants inhibited mitochondrial fusion, some GTPase mutants resulted in elongated mitochondria, suggesting fission inhibition. We show that the GED is dispensable for fusion and OPA1 oligomer formation but necessary for GTPase activity. Finally, splicing defect mutants displayed a posttranslational haploinsufficiency-like phenotype but retained domain-specific dysfunctions. Thus, OPA1 domain-specific mutants result in distinct impairments in mitochondrial dynamics, providing insight into OPA1 function and its contribution to ADOA pathogenesis and severity.

Asunto(s)

Mitocondrias , Atrofia Óptica Autosómica Dominante , Humanos , Mitocondrias/metabolismo , Membranas Mitocondriales/metabolismo , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Atrofia Óptica Autosómica Dominante/genética , Atrofia Óptica Autosómica Dominante/metabolismo , Atrofia Óptica Autosómica Dominante/patología , Mutación

RESUMEN

PURPOSE: Conjunctival melanoma is a rare and aggressive tumor with a propensity for regional and distant metastases. This study aimed to analyze BRAF/NRAS markers in conjunctival melanoma and their relationship with tumor recurrences and patient prognosis. METHODS: This retrospective, observational, single-center study included consecutive patients with an anatomopathological diagnosis of conjunctival melanoma, registered between January 1992 and December 2019. BRAF/NRAS mutations were analyzed using cobas®4800 kit (Roche®) in samples obtained by excisional or map biopsy. Additionally, the presence of other associated precancerous or tumor lesions was assessed. RESULTS: A total of 12 patients with positive histological samples for conjunctival melanoma were included (7 women, 5 men), with a mean age at diagnosis of 60 years and a mean evolution time of 6.38 ± 3.4 years. BRAF V600E mutation was observed in three biopsies (25%), similar to NRAS Q61X (25%). Recurrences occurred in all patients with positive BRAF or NRAS mutation, and five of these patients developed systemic dissemination (83.33%). Moreover, four of six patients with mutated BRAF or NRAS (66.66%) had histopathological findings of tumor or precancerous lesions. CONCLUSIONS: BRAF and NRAS mutations may be risk factors for recurrence and shorter survival in conjunctival melanoma, which would make these patients candidates for targeted therapies and comprehensive and individualized follow-up. All these data warrant standardized prospective studies.

Asunto(s)

Neoplasias Óseas , Neoplasias de la Conjuntiva , Melanoma , Neoplasias Cutáneas , Femenino , Humanos , Masculino , Neoplasias de la Conjuntiva/genética , Neoplasias de la Conjuntiva/patología , GTP Fosfohidrolasas/genética , Melanoma/genética , Melanoma/patología , Proteínas de la Membrana/genética , Mutación , Recurrencia Local de Neoplasia/genética , Estudios Observacionales como Asunto , Pronóstico , Estudios Prospectivos , Proteínas Proto-Oncogénicas B-raf/genética , Estudios Retrospectivos , Neoplasias Cutáneas/patología

RESUMEN

Previous studies have shown that peripheral nerve injury can lead to abnormal dendritic spine remodeling in spinal dorsal horn neurons. Inhibition of abnormal dendritic spine remodeling can relieve neuropathic pain. Electroacupuncture (EA) has a beneficial effect on the treatment of neuropathic pain, but the specific mechanism remains unclear. Evidence has shown that slit-robo GTPase activating protein 3 (srGAP3) and Rho GTPase (Rac1) play very important roles in dendritic spine remodeling. Here, we used srGAP3 siRNA and Rac1 activator CN04 to confirm the relationship between SrGAP3 and Rac1 and their roles in improving neuropathic pain with EA. Spinal nerve ligation (SNL) was used as the experimental model, and thermal withdrawal latency (TWL), mechanical withdrawal threshold (MWT), Western blotting, immunohistochemistry and Golgi-Cox staining were used to examine changes in behavioral performance, protein expression and dendritic spines. More dendritic spines and higher expression levels of srGAP3 were found in the initial phase of neuropathic pain. During the maintenance phase, dendritic spines were more mature, which was consistent with lower expression levels of srGAP3 and higher expression levels of Rac1-GTP. EA during the maintenance phase reduced the density and maturity of dendritic spines of rats with SNL, increased the levels of srGAP3 and reduced the levels of Rac1-GTP, while srGAP3 siRNA and CN04 reversed the therapeutic effects of EA. These results suggest that dendritic spines have different manifestations in different stages of neuropathic pain and that EA may inhibit the abnormal dendritic spine remodeling by regulating the srGAP3/Rac1 signaling pathway to alleviate neuropathic pain.

Asunto(s)

Animales , Ratas , Electroacupuntura , Neuralgia/metabolismo , Neuralgia/terapia , Nervios Espinales/metabolismo , Transducción de Señal , Ratas Sprague-Dawley , Proteína de Unión al GTP rac1/metabolismo , Espinas Dendríticas/metabolismo , GTP Fosfohidrolasas/metabolismo , Guanosina Trifosfato/metabolismo

RESUMEN

The final maturation step of the 60S ribosomal subunit requires the release of eukaryotic translation initiation factor 6 (human eIF6, yeast Tif6) to enter the pool of mature ribosomes capable of engaging in translation. This process is mediated by the concerted action of the Elongation Factor-like 1 (human EFL1, yeast Efl1) GTPase and its effector, the Shwachman-Bodian-Diamond syndrome protein (human SBDS, yeast Sdo1). Mutations in these proteins prevent the release of eIF6 and cause a disease known as Shwachman-Diamond Syndrome (SDS). While some mutations in EFL1 or SBDS result in insufficient proteins to meet the cell production of mature large ribosomal subunits, others do not affect the expression levels with unclear molecular defects. We studied the functional consequences of one such mutation using Saccharomyces cerevisiae Efl1 R1086Q, equivalent to human EFL1 R1095Q described in SDS patients. We characterised the enzyme kinetics and energetic basis outlining the recognition of this mutant to guanine nucleotides and Sdo1, and their interplay in solution. From our data, we propose a model where the conformational change in Efl1 depends on a long-distance network of interactions that are disrupted in mutant R1086Q, whereby Sdo1 and the guanine nucleotides no longer elicit the conformational changes previously described in the wild-type protein. These findings point to the molecular malfunction of an EFL1 mutant and its possible impact on SDS pathology.

Asunto(s)

GTP Fosfohidrolasas , Saccharomyces cerevisiae , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Nucleótidos de Guanina/metabolismo , Humanos , Factor 1 de Elongación Peptídica/metabolismo , Proteínas/metabolismo , Subunidades Ribosómicas Grandes de Eucariotas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo

RESUMEN

Objective: To analyze the frequency of KRAS, NRAS and BRAF hotspot mutations in circulating tumor DNA (ctDNA) from patients with metastatic colorectal cancer (mCRC). Methods: Observational, descriptive and retrospective study in mCRC patients with available ctDNA-based genotype of KRAS, NRAS and BRAF. Results: The frequencies of plasma mutations for KRAS, NRAS and BRAF were 34% (± 7), 4% (± 3) and 4% (± 3), respectively. Median overall survival of plasma-tested RAS/BRAF-mutated patients was 26.6 months (95% CI: 14.4-not estimable [NE]), while RAS/BRAF wild-type patients did not reach the median survival during follow-up. Median progression-free survival for RAS/BRAF wild-type and RAS/BRAF-mutated patients was 12 (95% CI: 7-NE) and 4 months (95% CI: 4-NE), respectively. Conclusion: Our work supports the utility of KRAS, NRAS and BRAF analysis in liquid biopsy from mCRC patients.

Asunto(s)

ADN Tumoral Circulante , Neoplasias del Colon , Neoplasias Colorrectales , Neoplasias del Recto , ADN Tumoral Circulante/genética , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , GTP Fosfohidrolasas/genética , Humanos , Biopsia Líquida , Proteínas de la Membrana/genética , Mutación , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Estudios Retrospectivos

RESUMEN

Neurons are highly polarized cells that rely on the intracellular transport of organelles. This process is regulated by molecular motors such as dynein and kinesins and the Rab family of monomeric GTPases that together help move cargo along microtubules in dendrites, somas, and axons. Rab5-Rab11 GTPases regulate receptor trafficking along early-recycling endosomes, which is a process that determines the intracellular signaling output of different signaling pathways, including those triggered by BDNF binding to its tyrosine kinase receptor TrkB. BDNF is a well-recognized neurotrophic factor that regulates experience-dependent plasticity in different circuits in the brain. The internalization of the BDNF/TrkB complex results in signaling endosomes that allow local signaling in dendrites and presynaptic terminals, nuclear signaling in somas and dynein-mediated long-distance signaling from axons to cell bodies. In this review, we briefly discuss the organization of the endocytic pathway and how Rab11-recycling endosomes interact with other endomembrane systems. We further expand upon the roles of the Rab11-recycling pathway in neuronal plasticity. Then, we discuss the BDNF/TrkB signaling pathways and their functional relationships with the postendocytic trafficking of BDNF, including axonal transport, emphasizing the role of BDNF signaling endosomes, particularly Rab5-Rab11 endosomes, in neuronal plasticity. Finally, we discuss the evidence indicating that the dysfunction of the early-recycling pathway impairs BDNF signaling, contributing to several neurodegenerative diseases.

Asunto(s)

Factor Neurotrófico Derivado del Encéfalo , Enfermedades Neurodegenerativas , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Dineínas/metabolismo , Endosomas/metabolismo , GTP Fosfohidrolasas/metabolismo , Hipocampo/metabolismo , Humanos , Enfermedades Neurodegenerativas/metabolismo , Transporte de Proteínas , Receptor trkB , Proteínas de Unión al GTP rab

RESUMEN

OBJECTIVES: Accumulating research have reported that microRNAs (miRNAs) play important roles in Retinoblastoma (RB). Nonetheless, the function and underlying mechanism of miR-181a-5p in RB remain ambiguous. METHODS: The relative expression levels of miR-181a-5p and NRAS mRNA were detected by quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). RB cell proliferation was measured using the Cell Counting Kit-8 (CCK-8) and 5'-Bromo-2'-deoxyuridine (BrdU) assays. Transwell assays and flow cytometry were performed to detect the migration, invasion, and apoptosis of RB cells. The interaction between miR-181a-5p and NRAS was explored using luciferase experiments, western blotting, and qRT-PCR. RESULTS: miR-181a-5p expression was found to be decreased in RB tissues and cell lines, and its expression was correlated with unfavorable pathological features of the patients. In vitro experiments revealed that miR-181a-5p reduced RB cell proliferation, migration, and invasion while enhancing apoptosis. Further research confirmed that NRAS is a direct target of miR-181a-5p. miR-181a-5p inhibited NRAS expression at both the mRNA and protein levels. Co-transfection of pcDNA-NRAS or NRAS small interfering RNA (siRNA) reversed the effects of miR-181a-5p mimics or miR-181a-5p inhibitors on RB cells. CONCLUSION: miR-181a-5p was significantly downregulated during the development of RB, and it suppressed the malignant behaviors of RB cells by targeting NRAS.

Asunto(s)

MicroARNs , Neoplasias de la Retina , Retinoblastoma , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , GTP Fosfohidrolasas/genética , Humanos , Proteínas de la Membrana/genética , MicroARNs/genética , Invasividad Neoplásica/genética , Proto-Oncogenes , Neoplasias de la Retina/genética , Retinoblastoma/genética , Retinoblastoma/patología