Ecdysteroids affect Drosophila ovarian stem cell niche formation and early germline differentiation

Ecdysteroids affect Drosophila ovarian stem cell niche formation and early germline differentiation. The steroid hormone ecdysone regulates germline development and stem cell niche establishment in the Drosophila ovary by modulating TGF-β signalling and cell adhesion

Production of Recombinant Alpha-Synuclein: Still No Standardized Protocol in Sight

Synucleinopathies are a group of neurodegenerative diseases, characterized by the abnormal accumulation of the protein alpha-synuclein (aSyn). aSyn is an intrinsically disordered protein that can adopt different aggregation states, some of which may be associated with disease. Therefore, understanding the transitions between such aggregation states may be essential for deciphering the molecular underpinnings underlying synucleinopathies. Recombinant aSyn is routinely produced and purified from E. coli in many laboratories, and in vitro preparations of aSyn aggregated species became central for modeling neurodegeneration in cell and animal models. Thus, reproducibility and reliability of such studies largely depends on the purity and homogeneity of aSyn preparations across batches and between laboratories. A variety of different methods are in use to produce and purify aSyn, which we review in this commentary. We also show how extraction buffer composition can affect aSyn aggregation, emphasizing the importance of standardizing protocols to ensure reproducibility between different laboratories and studies, which are essential for advancing the field

Type 2 Diabetes and Parkinson's Disease: A Focused Review of Current Concepts

Highly reproducible epidemiological evidence shows that type 2 diabetes (T2D) increases the risk and rate of progression of Parkinson's disease (PD), and crucially, the repurposing of certain antidiabetic medications for the treatment of PD has shown early promise in clinical trials, suggesting that the effects of T2D on PD pathogenesis may be modifiable. The high prevalence of T2D means that a significant proportion of patients with PD may benefit from personalized antidiabetic treatment approaches that also confer neuroprotective benefits. Therefore, there is an immediate need to better understand the mechanistic relation between these conditions and the specific molecular pathways affected by T2D in the brain. Although there is considerable evidence that processes such as insulin signaling, mitochondrial function, autophagy, and inflammation are involved in the pathogenesis of both PD and T2D, the primary aim of this review is to highlight the evidence showing that T2D-associated dysregulation of these pathways occurs not only in the periphery but also in the brain and how this may facilitate neurodegeneration in PD. We also discuss the challenges involved in disentangling the complex relationship between T2D, insulin resistance, and PD, as well as important questions for further research. © 2022 International Parkinson and Movement Disorder Society

Effects of alpha-synuclein post-translational modifications on metal binding

Parkinson’s disease is the second most common neurodegenerative disorder worldwide. Neurodegeneration in this pathology is characterized by the loss of dopaminergic neurons in the substantia nigra, coupled with cytoplasmic inclusions known as Lewy bodies containing α-synuclein. The brain is an organ that concentrates metal ions, and there is emerging evidence that a break-down in metal homeostasis may be a critical factor in a variety of neurodegenerative diseases. α-synuclein has emerged as an important metal-binding protein in the brain, whereas these interactions play an important role in its aggregation and might represent a link between protein aggregation, oxidative damage, and neuronal cell loss. Additionally, α-synuclein undergoes several post-translational modifications that regulate its structure and physiological function, and may be linked to the aggregation and/or oligomer formation. This review is focused on the interaction of this protein with physiologically relevant metal ions, highlighting the cases where metal-AS interactions profile as key modulators for its structural, aggregation, and membrane-binding properties. The impact of α-synuclein phosphorylation and N-terminal acetylation in the metal-binding properties of the protein are also discussed, underscoring a potential interplay between PTMs and metal ion binding in regulating α-synuclein physiological functions and its role in pathology.Fil: González, Nazareno. Laboratorio Max Planck de Biología Estructural, Química y Biofísica Molecular de Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario. Universidad Nacional de Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario; ArgentinaFil: Arcos López, Trinidad. Center for Research and Advanced Studies; MéxicoFil: König, Annekatrin. University of Göttingen; AlemaniaFil: Quintanar, Liliana. Center for Research and Advanced Studies; MéxicoFil: Menacho Márquez, Mauricio Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario. Universidad Nacional de Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario; Argentina. Max Planck Laboratory for Structural Biology, Chemistry and Molecular Biophysics of Rosario; ArgentinaFil: Outeiro, Tiago F.. University of Göttingen; Alemania. Max Planck Institute for Experimental Medicine; Alemania. University of Newcastle; Reino UnidoFil: Fernandez, Claudio Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario. Universidad Nacional de Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario; Argentina. Max Planck Laboratory for Structural Biology, Chemistry and Molecular Biophysics of Rosario; Argentina. Max Planck Institute for Biophysical Chemistry; Alemani

The alpha-synuclein oligomers activate nuclear factor of activated T-cell (NFAT) modulating synaptic homeostasis and apoptosis

Abstract Background Soluble oligomeric forms of alpha-synuclein (aSyn-O) are believed to be one of the main toxic species in Parkinson’s disease (PD) leading to degeneration. aSyn-O can induce Ca2+ influx, over activating downstream pathways leading to PD phenotype. Calcineurin (CN), a phosphatase regulated by Ca2+ levels, activates NFAT transcription factors that are involved in the regulation of neuronal plasticity, growth, and survival. Methods Here, using a combination of cell toxicity and gene regulation assays performed in the presence of classical inhibitors of the NFAT/CN pathway, we investigate NFAT’s role in neuronal degeneration induced by aSyn-O. Results aSyn-O are toxic to neurons leading to cell death, loss of neuron ramification and reduction of synaptic proteins which are reversed by CN inhibition with ciclosporin-A or VIVIT, a NFAT specific inhibitor. aSyn-O induce NFAT nuclear translocation and transactivation. We found that aSyn-O modulates the gene involved in the maintenance of synapses, synapsin 1 (Syn 1). Syn1 mRNA and protein and synaptic puncta are drastically reduced in cells treated with aSyn-O which are reversed by NFAT inhibition. Conclusions For the first time a direct role of NFAT in aSyn-O-induced toxicity and Syn1 gene regulation was demonstrated, enlarging our understanding of the pathways underpinnings synucleinopathies

Doxycycline inhibits α-synuclein-associated pathologies in vitro and in vivo

International audienceParkinson's disease (PD) and dementia with Lewy bodies (DLB) are neurodegenerative disorders characterized by the misfolding and aggregation of alpha-synuclein (aSyn). Doxycycline, a tetracyclic antibiotic shows neuroprotective effects, initially proposed to be due to its anti-inflammatory properties. More recently, an additional mechanism by which doxycycline may exert its neuroprotective effects has been proposed as it has been shown that it inhibits amyloid aggregation. Here, we studied the effects of doxycycline on aSyn aggregation in vivo, in vitro and in a cell free system using real-time quaking induced conversion (RT-QuiC). Using H4, SH-SY5Y and HEK293 cells, we found that doxycycline decreases the number and size of aSyn aggregates in cells. In addition, doxycycline inhibits the aggregation and seeding of recombinant aSyn, and attenuates the production of mitochondrial-derived reactive oxygen species. Finally, we found that doxycycline induces a cellular redistribution of aggregates in a C.elegans animal model of PD, an effect that is associated with a recovery of dopaminergic function. In summary, we provide strong evidence that doxycycline treatment may be an effective strategy against synucleinopathies

Cytosolic Trapping of a Mitochondrial Heat Shock Protein Is an Early Pathological Event in Synucleinopathies

Alpha-synuclein (aSyn) accumulates in intracellular inclusions in synucleinopathies, but the molecular mechanisms leading to disease are unclear. We identify the 10 kDa heat shock protein (HSP10) as a mediator of aSyn-induced mitochondrial impairments in striatal synaptosomes. We find an age-associated increase in the cytosolic levels of HSP10, and a concomitant decrease in the mitochondrial levels, in aSyn transgenic mice. The levels of superoxide dismutase 2, a client of the HSP10/HSP60 folding complex, and synaptosomal spare respiratory capacity are also reduced. Overexpression of HSP10 ameliorates aSyn-associated mitochondrial dysfunction and delays aSyn pathology in vitro and in vivo. Altogether, our data indicate that increased levels of aSyn induce mitochondrial deficits, at least partially, by sequestering HSP10 in the cytosol and preventing it from acting in mitochondria. Importantly, these alterations manifest first at presynaptic terminals. Our study not only provides mechanistic insight into synucleinopathies but opens new avenues for targeting underlying cellular pathologies. Szegő et al. identify HSP10 as a modulator of alpha-synuclein-induced mitochondrial impairment in striatal synaptosomes. Age-associated increase in the cytosolic and decrease in mitochondrial levels of HSP10 results in a reduction in the levels of SOD2 and of synaptosomal ATP production on demand. HSP10 overexpression delays alpha-synuclein pathology both in vitro and in vivo