Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik

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Publisher: search.filters.publisher.Public Library of ScienceSubject: search.filters.subject.Animal cell

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  • Article
    Citation - WoS: 24
    Citation - Scopus: 24
    Mice Doubly-Deficient in Lysosomal Hexosaminidase a and Neuraminidase 4 Show Epileptic Crises and Rapid Neuronal Loss
    (Public Library of Science, 2010) Seyrantepe, Volkan; Lema, Pablo; Caqueret, Aurore; Dridi, Larbi; Hadj, Samar Bel; Carpentier, Stephane; Boucher, Francine; Levade, Thierry; Carmant, Lionel; Gravel, Roy A.; Hamel, Edith; Vachon, Pascal; Di Cristo, Graziella; Michaud, Jacques L.; Morales, Carlos R.; Pshezhetsky, Alexey V.
    Tay-Sachs disease is a severe lysosomal disorder caused by mutations in the HexA gene coding for the a-subunit of lysosomal β-hexosaminidase A, which converts GM2 to GM3 ganglioside. Hexa-/- mice, depleted of b-hexosaminidase A, remain asymptomatic to 1 year of age, because they catabolise GM2 ganglioside via a lysosomal sialidase into glycolipid GA2, which is further processed by β-hexosaminidase B to lactosyl-ceramide, thereby bypassing the β-hexosaminidase A defect. Since this bypass is not effective in humans, infantile Tay-Sachs disease is fatal in the first years of life. Previously, we identified a novel ganglioside metabolizing sialidase, Neu4, abundantly expressed in mouse brain neurons. Now we demonstrate that mice with targeted disruption of both Neu4 and Hexa genes (Neu4-/-;Hexa-/-) show epileptic seizures with 40% penetrance correlating with polyspike discharges on the cortical electrodes of the electroencephalogram. Single knockout Hexa-/- or Neu4-/- siblings do not show such symptoms. Further, double-knockout but not single-knockout mice have multiple degenerating neurons in the cortex and hippocampus and multiple layers of cortical neurons accumulating GM2 ganglioside. Together, our data suggest that the Neu4 block exacerbates the disease in Hexa-/- mice, indicating that Neu4 is a modifier gene in the mouse model of Tay-Sachs disease, reducing the disease severity through the metabolic bypass. However, while disease severity in the double mutant is increased, it is not profound suggesting that Neu4 is not the only sialidase contributing to the metabolic bypass in Hexa-/- mice.
  • Article
    Citation - WoS: 10
    Citation - Scopus: 14
    Garlic Accelerates Red Blood Cell Turnover and Splenic Erythropoietic Gene Expression in Mice: Evidence for Erythropoietin-Independent Erythropoiesis
    (Public Library of Science, 2010) Akgül, Bünyamin; Lin, Kai-Wei; Yang, Hui-Mei Ou; Chen, Yen-Hui; Lu, Tzu-Huan; Chen, Chien-Hsiun; Kikuchi, Tateki; Chen, Yuan-Tsong; Tu, Chen-Pei D.
    Garlic (Allium sativum) has been valued in many cultures both for its health effects and as a culinary flavor enhancer. Garlic's chemical complexity is widely thought to be the source of its many health benefits, which include, but are not limited to, anti-platelet, procirculatory, anti-inflammatory, anti-apoptotic, neuro-protective, and anti-cancer effects. While a growing body of scientific evidence strongly upholds the herb's broad and potent capacity to influence health, the common mechanisms underlying these diverse effects remain disjointed and relatively poorly understood. We adopted a phenotypedriven approach to investigate the effects of garlic in a mouse model. We examined RBC indices and morphologies, spleen histochemistry, RBC half-lives and gene expression profiles, followed up by qPCR and immunoblot validation. The RBCs of garlic-fed mice register shorter half-lives than the control. But they have normal blood chemistry and RBC indices. Their spleens manifest increased heme oxygenase 1, higher levels of iron and bilirubin, and presumably higher CO, a pleiotropic gasotransmitter. Heat shock genes and those critical for erythropoiesis are elevated in spleens but not in bone marrow. The garlic-fed mice have lower plasma erythropoietin than the controls, however. Chronic exposure to CO of mice on garlic-free diet was sufficient to cause increased RBC indices but again with a lower plasma erythropoietin level than air-treated controls. Furthermore, dietary garlic supplementation and CO treatment showed additive effects on reducing plasma erythropoietin levels in mice. Thus, garlic consumption not only causes increased energy demand from the faster RBC turnover but also increases the production of CO, which in turn stimulates splenic erythropoiesis by an erythropoietinindependent mechanism, thus completing the sequence of feedback regulation for RBC metabolism. Being a pleiotropic gasotransmitter, CO may be a second messenger for garlic's other physiological effects.