Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik
Permanent URI for this collectionhttps://hdl.handle.net/11147/9
Browse
22 results
Search Results
Review Citation - WoS: 6Citation - Scopus: 8Molecular Trojan Horses for Treating Lysosomal Storage Diseases(Academic Press, 2023) Leal, Andres Felipe; Rintz, Estera; Çelik, Betül; Ago, Yasuhiko; León, Daniel; İnci, Orhan Kerim; Seyrantepe, VolkanLysosomal storage diseases (LSDs) are caused by monogenic mutations in genes encoding for proteins related to the lysosomal function. Lysosome plays critical roles in molecule degradation and cell signaling through interplay with many other cell organelles, such as mitochondria, endoplasmic reticulum, and peroxisomes. Even though several strategies (i.e., protein replacement and gene therapy) have been attempted for LSDs with promising results, there are still some challenges when hard-to-treat tissues such as bone (i.e., cartilages, ligaments, meniscus, etc.), the central nervous system (mostly neurons), and the eye (i.e., cornea, retina) are affected. Consistently, searching for novel strategies to reach those tissues remains a priority. Molecular Trojan Horses have been well-recognized as a potential alternative in several pathological scenarios for drug delivery, including LSDs. Even though molecular Trojan Horses refer to genetically engineered proteins to overcome the blood-brain barrier, such strategy can be extended to strategies able to transport and deliver drugs to specific tissues or cells using cell-penetrating peptides, monoclonal antibodies, vesicles, extracellular vesicles, and patient-derived cells. Only some of those platforms have been attempted in LSDs. In this paper, we review the most recent efforts to develop molecular Trojan Horses and discuss how this strategy could be implemented to enhance the current efficacy of strategies such as protein replacement and gene therapy in the context of LSDs. © 2023Conference Object Elimination of the B4galnt1 Gene Normalizes Lifespan and Prevents Pathology in Tay-Sachs Disease Mice(Elsevier, 2023) Seyrantepe, VolkanTay-Sachs disease is a neurodegenerative lysosomal storage disorder caused by mutations in the Hexa gene, which encodes the alpha subunit of lysosomal ß-hexaminidase A (HEXA). HEXA is responsible for the conversion of GM2 to GM3, therefore the deficiency leads to the accumulation of GM2 in the lysosomes, neurodegeneration, and eventual death. Currently, there is no efficient therapy for the disease yet.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: 5Citation - Scopus: 5Sialidase Neu4 Deficiency Is Associated With Neuroinflammation in Mice(Springer, 2021) Timur, Zehra Kevser; İnci, Orhan Kerim; Akyıldız Demir, Seçil; Seyrantepe, VolkanSialidases catalyze the removal of sialic acid residues from glycoproteins, oligosaccharides, and sialylated glycolipids. Sialidase Neu4 is in the lysosome and has broad substrate specificity. Previously generated Neu4-/- mice were viable, fertile and lacked gross morphological abnormalities, but displayed a marked vacuolization and lysosomal storage in lung and spleen cells. In addition, we showed that there is an increased level of GD1a ganglioside and a markedly decreased level of GM1 ganglioside in the brain of Neu4-/- mice. In this study, we further explored whether sialidase Neu4 deficiency causes neuroinflammation. We demostrated that elevated level of GD1a and GT1b is associated with an increased level of LAMP1-positive lysosomal vesicles and Tunel-positive neurons correlated with alterations in the expression of cytokines and chemokines in adult Neu4-/- mice. Astrogliosis and microgliosis were also significantly enhanced in the hippocampus, and cerebellum. These changes in brain immunity were accompanied by motor impairment in these mice. Our results indicate that sialidase Neu4 is a novel mediator of an inflammatory response in the mouse brain due to the altered catabolism of gangliosides.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 Characterization of the Human Sialidase Neu4 Gene Promoter(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2014) Seyrantepe, Volkan; Delman, MuratThere are 4 different sialidases that have been described in humans: lysosomal (Neu1), cytoplasmic (Neu2), plasma membrane (Neu3), and lysosomal/mitochondrial (Neu4). Previously, we have shown that Neu4 has a broad substrate specificity and is active against glyco-conjugates, including GM2 ganglioside, at the acidic pH of 3.2. An overexpression of Neu4 in transfected neuroglia cells from a Tay-Sachs patient shows a clearance of accumulated GM2, indicating the biological importance of Neu4. In this paper, we aimed to characterize a minimal promoter region of the human Neu4 gene in order to understand the molecular mechanism regulating its expression. We cloned 7 different DNA fragments from the human Neu4 promoter region into luciferase expression vectors for a reporter assay and also performed an electrophoretic mobility shift assay to demonstrate the binding of transcription factors. We demonstrated that -187 bp upstream of the Neu4 gene is a minimal promoter region for controlling transcription from the human Neu4 gene. The electrophoretic mobility shift assay showed that the minimal promoter region recruits a c-myc transcription factor, which might be responsible for regulation of Neu4 gene transcription. The data we obtained might be useful to discover small molecules, which control selective high expression of the human Neu4 gene, resulting in the normal morphological phenotype in the lysosomes of Tay-Sachs patients.Article Citation - WoS: 2Citation - Scopus: 2Identification of Cytoplasmic Sialidase Neu2-Associated Proteins by Lc-ms/Ms(Türk Biyokimya Derneği, 2019) Akyıldız Demir, Seçil; Seyrantepe, VolkanBackground: Cytoplasmic sialidase (NEU2) plays an active role in removing sialic acids from oligosaccharides, gly-copeptides, and gangliosides in mammalian cells. NEU2 is involved in various cellular events, including cancer metabolism, neuronal and myoblast differentiation, proliferation, and hypertrophy. However, NEU2-interacting protein(s) within the cell have not been identified yet. Objective: The aim of this study is to investigate NEU2 interacting proteins using two-step affinity purification (TAP) strategy combined with mass spectrometry analysis. Methods: In this study, NEU2 gene was cloned into the pCTAP expression vector and transiently transfected to COS-7 cells by using PEI. The most efficient expression time of NEU2- tag protein was determined by real-time PCR and Western blot analysis. NEU2-interacting protein(s) were investigated by using TAP strategy combined with two different mass spectrometry experiment; LC-MS/MS and MALDI TOF/TOF. Results: Here, mass spectrometry analysis showed four proteins; a-actin, beta-actin, calmodulin and histone H1.2 proteins are associated with NEU2. The interactions between NEU2 and actin filaments were verified by Western blot analysis and immunofluorescence analysis. Conclusions: Our study suggests that association of NEU2 with actin filaments and other protein(s) could be important for understanding the biological role of NEU2 in mammalian cells.
- «
- 1 (current)
- 2
- 3
- »