5 research outputs found
Effect of a ketogenic diet on the expression of potassium channels controlling neuronal excitability
The ketogenic diet (KD) contains a high amount of fat and very low carbohydrates which leads to ketone bodies (KB) synthesis as an energy source. In our laboratory, we elaborated a KD (70% fat, 25% proteins, <1% carbohydrates) to evaluate if KB modify the gene expression of Kv channels that regulate neuronal excitability, and the social behavior. KD was administered to P21 C57BL/6 male mice after weaning for 3 weeks with ad libitum intake. We kept a control group (CG) with normal diet. The blood KB and glucose levels were measured on days (D) 0, D7, D14 and D21. After one week of KD administration, the animals reached the highest amount of blood KB (2.81 ± 0.69 mmol/L) while the CG remained at 0.71 ± 0.13 mmol/L. KB levels in the CG did not change during the assay while decreased to 1.44 ± 0.43 mmol/L in the KD group. The body weight of KD mice was 25% lower than CG up to D14 reaching similar values thereafter. Using qPCR, we analyzed the expression of Kcnq2-5 mRNA in different brain regions. We found a significant increase of Kcnq3 in cerebellum and Kcnq4 in cortex. We performed behavioral tests after 3 weeks of KD consumption. The self-grooming behavior and thigmotaxis as well as the sociability and the social novelty presented no differences between KD group and CG. Our results suggest that KB modify Kcnq expression, then could modulate neuronal excitability, and may contribute to explaining the clinical effects of KD in refractory epilepsy and autism spectrum disordersFil: Stupniki, Sofia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Aztiria, Eugenio Manuel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Spitzmaul, Guillermo Federico. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaSAN 2022 MeetingBuenos AiresArgentinaSociedad Argentina de InvestigaciĂłn en Neurociencia
Novel variants in outer protein surface of flavin-containing monooxygenase 3 found in an Argentinian case with impaired capacity for trimethylamine N-oxygenation
Flavin-containing monooxygenase 3 (FMO3) is a polymorphic drug metabolizing enzyme associated with the genetic disorder trimethylaminuria. We phenotyped a white Argentinian 11-year-old girl by medical sensory evaluation. After pedigree analysis with her brother and parents, this proband showed to harbor a new allele p.(P73L; E158K; E308G) FMO3 in trans configuration with the second new one p.(F140S) FMO3. Recombinant FMO3 proteins of the wild-type and the novel two variants underwent kinetic analyses of their trimethylamine N-oxygenation activities. P73L; E158K; E308G and F140S FMO3 proteins exhibited moderately and severely decreased trimethylamine N-oxygenation capacities (âŒ50% and âŒ10% of wild-type FMO3, respectively). Amino acids P73 and F140 were located on the outer surface region in a crystallographic structure recently reported of a FMO3 analog. Changes in these positions would indirectly impact on key FAD-binding residues. This is the first report and characterization of a patient of fish odor syndrome caused by genetic aberrations leading to impaired FMO3-dependent N-oxygenation of trimethylamine found in the Argentinian population. We found novel structural determinants of FAD-binding domains, expanding the list of known disease-causing mutations of FMO3. Our results suggest that individuals homozygous for any of these new variants would develop a severe form of this disorder.Fil: Dionisio, Leonardo Raul. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Shimizu, Makiko. Showa Pharmaceutical University; JapĂłnFil: Stupniki, Sofia. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaFil: Oyama, Saki. Showa Pharmaceutical University; JapĂłnFil: Aztiria, Eugenio Manuel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Alda, Maximiliano. Instituto de DiagnĂłstico Infantil; ArgentinaFil: Yamazaki, Hiroshi. Showa Pharmaceutical University; JapĂłnFil: Spitzmaul, Guillermo Federico. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; Argentin
Association between clinical and genetic diagnosis in patients with LQT syndrome: importance of genetic testing
Long QT syndrome (LQTS) is a congenital genetic disorder that cause cardiac arrhythmia and sudden death. The genes more frequently implicated are those encoding for the K+ channels KCNQ1 (40 - 45 %) and HERG (40 â 45 %), and the Na+ channel Nav1.5 (5 â 8 %). Dysfunction in these channels leads to QT interval lengthening in ECG. Molecular identification of the causes of this disease contributes to better diagnosis, risk stratification and pharmacological treatment improvement. Our aim is to correlate clinical diagnosis with genetic variants of LQTS. We examined the LQT-associated genes KCNQ1, KCNH2 and SCN5A using gDNA extracted from 6 subjects. Five of them showed a prolonged QT interval on the ECG (>460 ms) while 1 first-degree relative presented a normal QT interval (A (p.Ser546=) in 2 subjects. In 1 patient we could not amplify exon 16, suggesting exon deletion. For KCNH2 we found the following variants: c.1692A>G (p.Leu564=) in 1 patient, c.1956T>C (p.Tyr652=) in 5 out of 6 cases and c.2690A>C (p.Lys897Thr) in 1 patient. Finally, we found the likely-pathogenic variant c.982C>T (p.Arg328Cys). For SCN5A no variants were detected at the tested exons. We found benign and pathological genetic variants in either KCNQ1 or KCNH2 genes of our population. No information about the exon 16 deletion for KCNQ1 as a pathological variant has been reported. To our knowledge, this is the first genetic test of LQTS performed in Argentina. Genetic characterization will impact on patient habits, avoiding risk situations such as sports, acute stress or cardiotoxic drugs therapies. Moreover, these studies will enable to set patient-oriented pharmacological treatments.Fil: Dionisio, Leonardo Raul. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaFil: Aztiria, Eugenio Manuel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaFil: Stupniki, Sofia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaFil: Dye, Leandro. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaFil: Onetto, Leonardo. Hospital Privado del Sur; ArgentinaFil: Gregorietti, Franco. Hospital Privado del Sur; ArgentinaFil: Keegan, Roberto. Hospital Privado del Sur; ArgentinaFil: Spitzmaul, Guillermo Federico. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaReuniĂłn Anual de Sociedades de BiocienciaMar del PlataArgentinaSociedad Argentina de InvestigaciĂłn ClĂnicaAsociaciĂłn Argentina de FarmacologĂa ExperimentalSociedad Argentina de BiologĂaSociedad Argentina de ProtozoologĂaAsociaciĂłn Argentina de NanomedicinasAsociaciĂłn Argentina de Ciencia y TecnologĂa de Animales de LaboratorioThe Histochemical Societ
Inner Hair Cell and Neuron Degeneration Contribute to Hearing Loss in a DFNA2-Like Mouse Model
DFNA2 is a progressive deafness caused by mutations in the voltage-activated potassium channel KCNQ4. Hearing loss develops with age from a mild increase in the hearing threshold to profound deafness. Studies using transgenic mice for Kcnq4 expressed in a mixed background demonstrated the implication of outer hair cells at the initial phase. However, it could not explain the last phase mechanisms of the disease. Genetic backgrounds are known to influence disease expressivity. To unmask the cause of profound deafness phenotype, we backcrossed the Kcnq4 knock-out allele to the inbred strain C3H/HeJ and investigated inner and outer hair cell and spiral ganglion neuron degeneration across the lifespan. In addition to the already reported outer hair cell death, the C3H/HeJ strain also exhibited inner hair cell and spiral ganglion neuron death. We tracked the spatiotemporal survival of cochlear cells by plotting cytocochleograms and neuronal counts at different ages. Cell loss progressed from basal to apical turns with age. Interestingly, the time-course of cell degeneration was different for each cell-type. While for outer hair cells it was already present by week 3, inner hair cell and neuronal loss started 30âŻweeks later. We also established that outer hair cell loss kinetics slowed down from basal to apical regions correlating with KCNQ4 expression pattern determined in wild-type mice. Our findings indicate that KCNQ4 plays differential roles in each cochlear cell-type impacting in their survival ability. Inner hair cell and spiral ganglion neuron death generates severe hearing loss that could be associated with the last phase of DFNA2.Fil: Carignano, Camila. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaFil: Barila, Esteban Pablo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaFil: RĂas, Ezequiel Ignacio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Dionisio, Leonardo Raul. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaFil: Aztiria, Eugenio Manuel. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; ArgentinaFil: Spitzmaul, Guillermo Federico. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentin
Molecular mechanisms of cell death in a mouse model of progressive hearing loss
KCNQ4 is a voltage-gated K+ channel whose dysfunction in the inner ear is the main cause of the progressive hearing loss (HL) DFNA2. It develops in 2 phases: first, a mild HL (40-60 dB) and later, it progresses to a profound HL (> 90 dB). Previously, using a knock out mouse model of the human DFNA2 (Kcnq4-/-), we reported that outer hair cell (OHC) degeneration may explain the first phase of HL and inner hair cell (IHC) and spiral ganglion neuron (SGN) degeneration occur in the second phase of HL. Now, we performed a functional hearing test, correlating these results with the molecular events leading to cell death and ultrastructural changes in the Organ of Cortiâs surface in both phases. We observed a profound HL starting at middle-aged (40-week-old (W)) Kcnq4-/- mice, as revealed by PreyerÂŽs reflex test. By immunofluorescence, we found caspase 3- mediated apoptosis (Cas-3) in SGNs and OHCs of Kcnq4-/- mice at different time points: in SGNs it was found late, at 54W and 68W, which correlates with our functional studies elucidating the profound HL of the last phase. On the other hand, OHCs showed a Cas-3 positive signal in 4W and 10W Kcnq4-/- mice, which could explain the mild HL of the first phase of DFNA2. IHCs did not show Cas-3 signal but they exhibited remarkable stereocilia defects by scanning microscopy, such as fusion and giant stereocilia in old mice. Collectively, these results are useful to understand the mechanisms involved in the human DFNA2.Fil: Carignano, Camila. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Vera, Marcela Sonia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Dionisio, Leonardo Raul. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Aztiria, Eugenio Manuel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Rias, Ezequiel Ignacio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaFil: Spitzmaul, Guillermo Federico. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂmicas de BahĂa Blanca; Argentina. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; ArgentinaXXXV Annual Meeting of the Argentinian Society for Neuroscience ResearchBuenos AiresArgentinaSociedad Argentina de InvestigaciĂłn en Neurociencia