Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik
Permanent URI for this collectionhttps://hdl.handle.net/11147/9
Browse
9 results
Search Results
Article Citation - WoS: 4Citation - Scopus: 4Autophagic Flux Is Impaired in the Brain Tissue of Tay-Sachs Disease Mouse Model(Public Library of Science, 2023) Şengül, Tuğçe; Can, Melike; Ateş, Nurselin; Seyrantepe, VolkanTay-Sachs disease is a lethal lysosomal storage disorder caused by mutations in the HexA gene encoding the α subunit of the lysosomal β-hexosaminidase enzyme (HEXA). Abnormal GM2 ganglioside accumulation causes progressive deterioration in the central nervous system in Tay-Sachs patients. Hexa-/-mouse model failed to display abnormal phenotype. Recently, our group generated Hexa-/-Neu3-/-mouse showed severe neuropathological indications similar to Tay-Sachs patients. Despite excessive GM2 ganglioside accumulation in the brain and visceral organs, the regulation of autophagy has not been clarified yet in the Tay-Sachs disease mouse model. Therefore, we investigated distinct steps of autophagic flux using markers including LC3 and p62 in four different brain regions from the Hexa-/-Neu3-/-mice model of Tay-Sachs disease. Our data revealed accumulated autophagosomes and autophagolysosomes indicating impairment in autophagic flux in the brain. We suggest that autophagy might be a new therapeutic target for the treatment of devastating Tay-Sachs disease. © 2023 Sengul et al.Article Citation - WoS: 6Citation - Scopus: 6Analysis of Brain Lipids in the Early-Onset Tay–sachs Disease Mouse Model With the Combined Deficiency of Β-Hexosaminidase a and Neuraminidase 3(Frontiers Media S.A., 2022) Can, Melike; Şengül, Tuğçe; Akyıldız Demir, Seçil; İnci, Orhan K.; Basırlı, Hatice Hande; Seyrantepe, VolkanTay–Sachs disease is an autosomal recessively inherited lysosomal storage disease that results from loss-of-function mutations in the HEXA gene coding βhexosaminidase A. HEXA gene deficiency affects the central nervous system owing to GM2 ganglioside accumulation in lysosomes resulting in progressive neurodegeneration in patients. We recently generated a novel mice model with a combined deficiency of βhexosaminidase A and neuraminidase 3 (Hexa−/−Neu3−/−) that mimics both the neuropathological and clinical abnormalities of early-onset Tay–Sachs disease. Here, we aimed to explore the secondary accumulation of lipids in the brain of Hexa−/ −Neu3−/− mice.Conference Object Brain Lipid Profile of Early Onset Tay-Sachs Disease Mouse Model(Springernature, 2020) Şengül, Tuğçe; Can, Melike; Akyıldız Demir, Seçil; Klose, C.; Surma, M.; Seyrantepe, Volkan[Abstract Not Available]Conference Object Role of Oxidative Stress in the Pathogenesis of Tay-Sachs Disease Mouse Model(Springernature, 2020) Ateş, Nurselin; Başırlı, Hatice Hande; Çalışkan, Tufan Utku; Nalbant, Ayten; Seyrantepe, Volkan[Abstract Not Available]Article Citation - WoS: 37Citation - Scopus: 40Gm2 Ganglioside Accumulation Causes Neuroinflammation and Behavioral Alterations in a Mouse Model of Early Onset Tay-Sachs Disease(BioMed Central Ltd., 2020) Akyıldız Demir, Seçil; Timur, Zehra Kevser; Ateş, Nurselin; Martinez, Luis Alarcon; Seyrantepe, VolkanBackground Tay-Sachs disease (TSD), a type of GM2-gangliosidosis, is a progressive neurodegenerative lysosomal storage disorder caused by mutations in the alpha subunit of the lysosomal beta-hexosaminidase enzyme. This disease is characterized by excessive accumulation of GM2 ganglioside, predominantly in the central nervous system. Although Tay-Sachs patients appear normal at birth, the progressive accumulation of undegraded GM2 gangliosides in neurons leads to death. Recently, an early onset Tay-Sachs disease mouse model, with genotypeHexa-/-Neu3-/-, was generated. Progressive accumulation of GM2 led to premature death of the double KO mice. Importantly, this double-deficient mouse model displays typical features of Tay-Sachs patients, such as cytoplasmic vacuolization of nerve cells, deterioration of Purkinje cells, neuronal death, deceleration in movement, ataxia, and tremors. GM2-gangliosidosis is characterized by acute neurodegeneration preceded by activated microglia expansion, macrophage, and astrocyte activation, along with the production of inflammatory mediators. However, the mechanism of disease progression inHexa-/-Neu3-/-mice, relevant to neuroinflammation is poorly understood. Method In this study, we investigated the onset and progression of neuroinflammatory changes in the cortex, cerebellum, and retina ofHexa-/-Neu3-/-mice and control littermates by using a combination of molecular genetics and immunochemical procedures. Results We found elevated levels of pro-inflammatory cytokine and chemokine transcripts, such as Ccl2, Ccl3, Ccl4, and Cxcl10 and also extensive microglial and astrocyte activation and proliferation, accompanied by peripheral blood mononuclear cell infiltration in the vicinity of neurons and oligodendrocytes. Behavioral tests demonstrated a high level of anxiety, and age-dependent loss in both spatial learning and fear memory inHexa-/-Neu3-/-mice compared with that in the controls. Conclusion Altogether, our data suggest thatHexa-/-Neu3-/-mice display a phenotype similar to Tay-Sachs patients suffering from chronic neuroinflammation triggered by GM2 accumulation. Furthermore, our work contributes to better understanding of the neuropathology in a mouse model of early onset Tay-Sachs disease.Article Citation - WoS: 28Citation - Scopus: 31Lysosomal Cathepsin a Plays a Significant Role in the Processing of Endogenous Bioactive Peptides(Frontiers Media S.A., 2016) Timur, Zehra Kevser; Akyıldız Demir, Seçil; Seyrantepe, VolkanLysosomal serine carboxypeptidase Cathepsin A (CTSA) is a multifunctional enzyme with distinct protective and catalytic function. CTSA present in the lysosomal multienzyme complex to facilitate the correct lysosomal routing, stability and activation of with beta-galactosidase and alpha-neuraminidase. Beside CTSA has role in inactivation of bioactive peptides including bradykinin, substances P, oxytocin, angiotensin I and endothelin-I by cleavage of 1 or 2 amino acid(s) from C-terminal ends. In this study, we aimed to elucidate the regulatory role of CTSA on bioactive peptides in knock-in mice model of CTSA(S190A). We investigated the level of bradykinin, substances P, oxytocin, angiotensin I and endothelin-I in the kidney, liver, lung, brain and serum from CTSA(S190A) mouse model at 3- and 6-months of age. Our results suggest CTSA selectively contributes to processing of bioactive peptides in different tissues from CTSA(S190A) mice compared to age matched WT mice.Article Citation - WoS: 54Citation - Scopus: 58Murine Sialidase Neu3 Facilitates Gm2 Degradation and Bypass in Mouse Model of Tay-Sachs Disease(Elsevier, 2018) Seyrantepe, Volkan; Akyıldız Demir, Seçil; Timur, Zehra Kevser; Von Gerichten, Johanna; Marsching, Christian; Erdemli, Esra; Öztaş, Emin; Takahashi, Kohta; Yamaguchi, Kazunori; Ateş, Nurselin; Dönmez Demir, Buket; Dalkara, Turgay; Erich, Katrin; Hopf, Carsten; Sandhoff, Roger; Miyagi, TaekoTay-Sachs disease is a severe lysosomal storage disorder caused by mutations in Hexa, the gene that encodes for the α subunit of lysosomal β-hexosaminidase A (HEXA), which converts GM2 to GM3 ganglioside. Unexpectedly, Hexa−/− mice have a normal lifespan and show no obvious neurological impairment until at least one year of age. These mice catabolize stored GM2 ganglioside using sialidase(s) to remove sialic acid and form the glycolipid GA2, which is further processed by β-hexosaminidase B. Therefore, the presence of the sialidase (s) allows the consequences of the Hexa defect to be bypassed. To determine if the sialidase NEU3 contributes to GM2 ganglioside degradation, we generated a mouse model with combined deficiencies of HEXA and NEU3. The Hexa−/− Neu3−/− mice were healthy at birth, but died at 1.5 to 4.5 months of age. Thin-layer chromatography and mass spectrometric analysis of the brains of Hexa−/− Neu3−/− mice revealed the abnormal accumulation of GM2 ganglioside. Histological and immunohistochemical analysis demonstrated cytoplasmic vacuolation in the neurons. Electron microscopic examination of the brain, kidneys and testes revealed pleomorphic inclusions of many small vesicles and complex lamellar structures. The Hexa−/− Neu3−/− mice exhibited progressive neurodegeneration with neuronal loss, Purkinje cell depletion, and astrogliosis. Slow movement, ataxia, and tremors were the prominent neurological abnormalities observed in these mice. Furthermore, radiographs revealed abnormalities in the skeletal bones of the Hexa−/− Neu3−/− mice. Thus, the Hexa−/− Neu3−/− mice mimic the neuropathological and clinical abnormalities of the classical early-onset Tay-Sachs patients, and provide a suitable model for the future pre-clinical testing of potential treatments for this condition.Article Citation - WoS: 12Citation - Scopus: 15Effects of Cell-Mediated Osteoprotegerin Gene Transfer and Mesenchymal Stem Cell Applications on Orthodontically Induced Root Resorption of Rat Teeth(Oxford University Press, 2017) Amuk, Nisa Gül; Kurt, Gökmen; Baran, Yusuf; Seyrantepe, Volkan; Kartal Yandım, Melis; Adan, Aysun; Akyıldız Demir, Seçil; Kiraz, Yağmur; Sönmez, Mehmet FatihAim: The aim of this study is to evaluate and compare therapeutic effects of mesenchymal stem cell (MSCs) and osteoprotegerin (OPG) gene transfer applications on inhibition and/or repair of orthodontically induced inflammatory root resorption (OIIRR). Materials and methods: Thirty Wistar rats were divided into four groups as untreated group (negative control), treated with orthodontic appliance group (positive control), MSCs injection group, and OPG transfected MSCs [gene therapy (GT) group]. About 100 g of orthodontic force was applied to upper first molar teeth of rats for 14 days. MSCs and transfected MSC injections were performed at 1st, 6th, and 11th days to the MSC and GT group rats. At the end of experiment, upper first molar teeth were prepared for genetical, scanning electron microscopy (SEM), fluorescent microscopy, and haematoxylin eosin-tartrate resistant acid phosphatase staining histological analyses. Number of total cells, number of osteoclastic cells, number of resorption lacunae, resorption area ratio, SEM resorption ratio, OPG, RANKL, Cox-2 gene expression levels at the periodontal ligament (PDL) were calculated. Paired t-test, Kruskal-Wallis, and chi-square tests were performed. Results: Transferred MSCs showed marked fluorescence in PDL. The results revealed that number of osteoclastic cells, resorption lacunae, resorption area ratio, RANKL, and Cox-2 were reduced after single MSC injections significantly (P < 0.05). GT group showed the lowest number of osteoclastic cells (P < 0.01), number of resorption lacunae, resorption area ratio, and highest OPG expression (P < 0.001). Conclusions: Taken together all these results, MSCs and GT showed marked inhibition and/or repair effects on OIIRR during orthodontic treatment on rats.Article Citation - WoS: 11Citation - Scopus: 11Mice With Catalytically Inactive Cathepsin a Display Neurobehavioral Alterations(Hindawi Publishing Corporation, 2017) Çalhan, Osman Yipkin; Seyrantepe, VolkanThe lysosomal carboxypeptidase A, Cathepsin A (CathA), is a serine protease with two distinct functions. CathA protects β-galactosidase and sialidase Neu1 against proteolytic degradation by forming a multienzyme complex and activates sialidase Neu1. CathA deficiency causes the lysosomal storage disease, galactosialidosis. These patients present with a broad range of clinical phenotypes, including growth retardation, and neurological deterioration along with the accumulation of the vasoactive peptide, endothelin-1, in the brain. Previous in vitro studies have shown that CathA has specific activity against vasoactive peptides and neuropeptides, including endothelin-1 and oxytocin. A mutant mouse with catalytically inactive CathA enzyme (CathAS190A) shows increased levels of endothelin-1. In the present study, we elucidated the involvement of CathA in learning and long-term memory in 3-, 6-, and 12-month-old mice. Hippocampal endothelin-1 and oxytocin accumulated in CathAS190A mice, which showed learning impairments as well as long-term and spatial memory deficits compared with wild-type littermates, suggesting that CathA plays a significant role in learning and in memory consolidation through its regulatory role in vasoactive peptide processing.