Project description:The peri- and postmenopausal periods in women are associated with decreases in circulating estrogen levels, marked acceleration of age-related bone loss and increased risk of fracture. However, despite the clinical importance of postmenopausal bone loss, our molecular understanding of this process is incomplete. Here, we used co-expression network analysis to gain novel insight into the molecular mechanisms mediating bone loss in ovariectomized (OVX) mice, a model of human menopause. Expression profiles from intact and OVX mice from a panel of inbred strains were used to generate a co-expression network consisting of 29 modules. Genes in network module 25 were decreased by OVX in all strains. Module 25 was enriched for genes involved in the response to oxidative stress, a process known to be an upstream causal factor for OVX-induced bone loss. It was also found that module 25 homologs were co-expressed in human bone marrow and were enriched for genes with evidence of genetic association with bone mineral density (BMD) in women. Alpha synuclein (Snca) was the most highly connected “hub” genes in module 25 and its in vivo knockout resulted in a 40% reduction in OVX-induced bone loss. Furthermore, protection was associated with the targeted alteration of genes in specific network modules, including module 10. Our results identify a gene module associated with OVX-induced bone loss and demonstrate that Snca regulates ovariectomy-induced bone loss by controlling bone network dynamics.
Project description:The peri- and postmenopausal periods in women are associated with decreases in circulating estrogen levels, marked acceleration of age-related bone loss and increased risk of fracture. However, despite the clinical importance of postmenopausal bone loss, our molecular understanding of this process is incomplete. Here, we used co-expression network analysis to gain novel insight into the molecular mechanisms mediating bone loss in ovariectomized (OVX) mice, a model of human menopause. Expression profiles from intact and OVX mice from a panel of inbred strains were used to generate a co-expression network consisting of 29 modules. Genes in network module 25 were decreased by OVX in all strains. Module 25 was enriched for genes involved in the response to oxidative stress, a process known to be an upstream causal factor for OVX-induced bone loss. It was also found that module 25 homologs were co-expressed in human bone marrow and were enriched for genes with evidence of genetic association with bone mineral density (BMD) in women. Alpha synuclein (Snca) was the most highly connected “hub” genes in module 25 and its in vivo knockout resulted in a 40% reduction in OVX-induced bone loss. Furthermore, protection was associated with the targeted alteration of genes in specific network modules, including module 10. Our results identify a gene module associated with OVX-induced bone loss and demonstrate that Snca regulates ovariectomy-induced bone loss by controlling bone network dynamics.
Project description:GBA mutations are major risk factors for Parkinson’s disease (PD) and Dementia with Lewy Bodies (DLB), two common α-synucleinopathies associated with cognitive impairment. Here, we investigated the role of GBA mutations in cognitive decline by utilizing Gba L444P mutant mice, SNCA transgenic (tg), and Gba-SNCA double mutant mice. Notably, Gba mutant mice showed early cognitive deficits but no PD-like motor deficits up to 12 months old. Conversely, SNCA tg mice displayed age-related motor deficits but no cognitive abnormalities. Gba-SNCA mice exhibited exacerbated motor deficits and cognitive decline. Immunohistological analysis revealed cortical phospho-α-synuclein pathology in SNCA tg mice, which was exacerbated in Gba-SNCA mice, especially in layer 5 cortical neurons. Significantly, Gba mutant mice did not show α-synuclein pathology. Single-nucleus RNA sequencing of cortices instead uncovered selective synaptic vesicle cycle defects in excitatory neurons of Gba mutant and Gba-SNCA mice, via robust downregulation in gene networks regulating synapse vesicle cycle and synapse assembly. Meanwhile SNCA tg mice displayed broader synaptic changes. Immunohistochemical and electron microscopic analyses validated these findings. Together, our results indicate that Gba mutations, while exacerbating pre-existing α-synuclein aggregation and PD-like motor deficits, contribute to cognitive deficits through α-synuclein-independent mechanisms, likely involving dysfunction in synaptic vesicle endocytosis. Additionally, Gba-SNCA mice are a valuable model for studying cognitive and motor deficits in PD and DLB
Project description:Alpha-Synuclein (Snca) regulates ovariectomy-induced bone loss by altering the expression of genes in specific bone network modules
Project description:One strategy to drugging undruggable proteins is to directly target the mRNA that encodes them, thereby inhibit translation and reducing protein levels. Inforna, a sequence-based design approach to target RNA, enables the design of a small molecule Synucleozid that binds SNCA mRNA which encodes alpha-synuclein. Herein, we investigate the selectivity of Synucleozid on the whole transcriptome. Based on mechanistic studies, Synucleozid targets IRE locates in 5' UTR of SNCA mRNA and reduces alpha-synuclein protein levels by decreasing the amount of SNCA mRNA loaded into polysomes. Different from alpha-synuclein siRNA, Synucleozid binds mRNA and affect its function without regulating mRNA expression.
Project description:A major barrier to research on Parkinson’s disease (PD) is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells (iPSCs) from patients with PD and differentiate them into neurons affected by disease. We created an iPSC model of PD caused by triplication of SNCA encoding α-synuclein. α-Synuclein dysfunction is common to all forms of PD, and SNCA triplication leads to fully penetrant familial PD with accelerated pathogenesis. After differentiation of iPSCs into neurons enriched for midbrain dopaminergic subtypes, those from the patient contain double α-synuclein protein compared to those from an unaffected relative, precisely recapitulating the cause of PD in these individuals. A measurable biomarker makes this model ideal for drug screening for compounds that reduce levels of α-synuclein, and for mechanistic experiments to study PD pathogenesis. This gene expression microarray study was carried out as part of the validation process for demonstrating that the generated iPSC lines are pluripotent. 5 samples were analysed: two clonal iPSC lines from each of two genotypes (four in total; AST denoting alpha-synuclein triplication and NAS denoting normal alpha-synuclein), a human embryonic stem cell line (SHEF4). All cultured in self-renewal conditions, mTeSR1
Project description:A major barrier to research on Parkinson’s disease (PD) is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells (iPSCs) from patients with PD and differentiate them into neurons affected by disease. We created an iPSC model of PD caused by triplication of SNCA encoding α-synuclein. α-Synuclein dysfunction is common to all forms of PD, and SNCA triplication leads to fully penetrant familial PD with accelerated pathogenesis. After differentiation of iPSCs into neurons enriched for midbrain dopaminergic subtypes, those from the patient contain double α-synuclein protein compared to those from an unaffected relative, precisely recapitulating the cause of PD in these individuals. A measurable biomarker makes this model ideal for drug screening for compounds that reduce levels of α-synuclein, and for mechanistic experiments to study PD pathogenesis. This SNP microarray study was carried out to confirm presence of SNCA triplication in the affected subject and the derived cell lines.
Project description:A major barrier to research on Parkinson’s disease (PD) is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells (iPSCs) from patients with PD and differentiate them into neurons affected by disease. We created an iPSC model of PD caused by triplication of SNCA encoding ?-synuclein. ?-Synuclein dysfunction is common to all forms of PD, and SNCA triplication leads to fully penetrant familial PD with accelerated pathogenesis. After differentiation of iPSCs into neurons enriched for midbrain dopaminergic subtypes, those from the patient contain double ?-synuclein protein compared to those from an unaffected relative, precisely recapitulating the cause of PD in these individuals. A measurable biomarker makes this model ideal for drug screening for compounds that reduce levels of ?-synuclein, and for mechanistic experiments to study PD pathogenesis. This SNP microarray study was carried out to confirm presence of SNCA triplication in the affected subject and the derived cell lines. 11 samples were analysed: genomic DNA from the two subjects in the study, the two parent fibroblast lines (AST denoting alpha-synuclein triplication and NAS denoting normal alpha-synuclein), two iPSC lines from each parent fibroblast line (four in total), a human embryonic stem cell line (SHEF4) and two neuronal samples one each from AST and NAS iPSCs).
Project description:A major barrier to research on Parkinson’s disease (PD) is inaccessibility of diseased tissue for study. One solution is to derive induced pluripotent stem cells (iPSCs) from patients with PD and differentiate them into neurons affected by disease. We created an iPSC model of PD caused by triplication of SNCA encoding α-synuclein. α-Synuclein dysfunction is common to all forms of PD, and SNCA triplication leads to fully penetrant familial PD with accelerated pathogenesis. After differentiation of iPSCs into neurons enriched for midbrain dopaminergic subtypes, those from the patient contain double α-synuclein protein compared to those from an unaffected relative, precisely recapitulating the cause of PD in these individuals. A measurable biomarker makes this model ideal for drug screening for compounds that reduce levels of α-synuclein, and for mechanistic experiments to study PD pathogenesis. This gene expression microarray study was carried out as part of the validation process for demonstrating that the generated iPSC lines are pluripotent. 15 samples were analysed: the two parent fibroblast lines (AST denoting alpha-synuclein triplication and NAS denoting normal alpha-synuclein), two iPSC lines from each parent fibroblast line (four in total), a human embryonic stem cell line (SHEF4) and eight neuronal samples (each iPSC line differentiated into a neuronal population enriched for dopaminergic neurons, at two different time points).
Project description:For this study we selected a gene, α-synuclein (SNCA), that is consistently under-expressed in MCF7 cells and breast tumors. Following transfection with an SNCA expression construct, two stable MCF7 clones (named MCF7-SNCA #1 and 2) were selected and examined for expression differences relative to the parental MCF7 cells.