Adeno-associated viral vectors for functional intravenous gene transfer throughout the non-human primate brain
By onCrossing the blood–brain barrier in primates is a major obstacle for gene delivery to the brain. Adeno-associated viruses (AAVs) promise robust, non-invasive gene delivery from the bloodstream to the brain. However, unlike in rodents, few neurotropic AAVs efficiently cross the blood–brain barrier in non-human primates. Here we report on AAV.CAP-Mac, an engineered variant identified by screening in adult marmosets and newborn macaques, which has improved delivery efficiency in the brains of multiple non-human primate species: marmoset, rhesus macaque and green monkey. CAP-Mac is neuron biased in infant Old World primates, exhibits broad tropism in adult rhesus macaques and is vasculature biased in adult marmosets. We demonstrate applications of a single, intravenous dose of CAP-Mac to deliver functional GCaMP for ex vivo calcium imaging across multiple brain areas, or a cocktail of fluorescent reporters for Brainbow-like labelling throughout the macaque brain, circumventing the need for germline manipulations in Old World primates. As such, CAP-Mac is shown to have potential for non-invasive systemic gene transfer in the brains of non-human primates.
Structural and biochemical insights into lipid transport by VPS13 proteins
By onVPS13 proteins are proposed to function at contact sites between organelles as bridges for lipids to move directionally and in bulk between organellar membranes. VPS13s are anchored between membranes via interactions with receptors, including both peripheral and integral membrane proteins. Here we present the crystal structure of VPS13s adaptor binding domain (VAB) complexed with a Pro-X-Pro peptide recognition motif present in one such receptor, the integral membrane protein Mcp1p, and show biochemically that other Pro-X-Pro motifs bind the VAB in the same site. We further demonstrate that Mcp1p and another integral membrane protein that interacts directly with human VPS13A, XK, are scramblases. This finding supports an emerging paradigm of a partnership between bulk lipid transport proteins and scramblases. Scramblases can re-equilibrate lipids between membrane leaflets as lipids are removed from or inserted into the cytosolic leaflet of donor and acceptor organelles, respectively, in the course of protein-mediated transport.
Simulations predict differing phase responses to excitation vs. inhibition intheta-resonant pyramidal neurons
By onThis research highlights how cortical neurons respond differently to oscillatory inputs, impacting neuronal responses to network state shifts.
Synapsin E-domain is essential for α-synuclein function
By onSynucleins and synapsins are thought to cooperate to regulate synaptic vesicle recycling, but the mechanism is not known. Here we identify the synapsin E-domain as an essential binding partner of α-syn, enabling the function of α-syn at the synapse.
Neuromelanin accumulation drives endogenous synucleinopathy in non-human primates
By onA new NHP PD model was developed by inducing neuromelanin (NM) accumulation in dopaminergic neurons, leading to synucleinopathy and neuron degeneration similar to human PD neuropathology. Lowering NM levels may offer PD therapeutic strategies.
Genome-wide determinants of mortality and motor progression in Parkinson’s disease
By onThe authors examined the impact of gene variants on mortality and cognitive impairment in PD. Only the non-Gaucher disease causing GBA PD risk variant E326K, of the known PD risk variants, was associated with progression in PD.
Dopamine transporter imaging predicts clinically‐defined α‐synucleinopathy in REM sleep behavior disorder
By onIndividuals with idiopathic rapid eye movement sleep behavior disorder (iRBD) are at high risk for a clinical diagnosis of an α‐synucleinopathy (aSN). They could serve as a key population for disease‐modifying trials. Abnormal dopamine transporter (DAT) imaging is a strong candidate biomarker for risk of aSN diagnosis in iRBD. Our primary objective was to identify a quantitative measure of DAT imaging that predicts diagnosis of clinically‐defined aSN in iRBD.
Central and Peripheral Inflammation: Connecting the Immune Responses of Parkinson’s Disease
By onAuthors highlight the important work being done that implicates central and peripheral inflammation in playing a role in PD.
Regulation of mitophagy by the NSL complex underlies genetic risk for Parkinson’s disease at 16q11.2 and MAPT H1 loci
By onImpaired mitophagy is linked to familial PD. New study identifies KAT8 and KANSL1 as regulators of PINK1-dependent mitophagy, suggesting their role in idiopathic Parkinson’s. KANSL1 may be crucial in the disease, offering potential drug targets.
Neuropathological Features of Gaucher Disease and Gaucher Disease with Parkinsonism
By onDeficient acid β-glucocerebrosidase activity due to biallelic mutations in GBA1 results in Gaucher disease (GD). Patients with this lysosomal storage disorder exhibit a wide range of associated manifestations, spanning from virtually asymptomatic adults to infants with severe neurodegeneration. While type 1 GD (GD1) is considered non-neuronopathic, a small subset of patients develop parkinsonian features. Variants in GBA1 are also an important risk factor for several common Lewy body disorders (LBDs). Neuropathological examinations of patients with GD, including those who developed LBDs, are rare. GD primarily affects macrophages, and perivascular infiltration of Gaucher macrophages is the most common neuropathologic finding. However, the frequency of these clusters and the affected anatomical region varies. GD affects astrocytes, and, in neuronopathic GD, neurons in cerebral cortical layers 3 and 5, layer 4b of the calcarine cortex, and hippocampal regions CA2–4. In addition, several reports describe selective degeneration of the cerebellar dentate nucleus in chronic neuronopathic GD. GD1 is characterized by astrogliosis without prominent neuronal loss. In GD-LBD, widespread Lewy body pathology is seen, often involving hippocampal regions CA2–4. Additional neuropathological examinations in GD are sorely needed to clarify disease-specific patterns and elucidate causative mechanisms relevant to GD, and potentially to more common neurodegenerative diseases.
Neuronal hyperactivity-induced oxidant stress promotes in vivo α-synuclein brain spreading
By onInterneuronal transfer and brain spreading of pathogenic proteins are features of neurodegenerative diseases. Pathophysiological conditions and mechanisms affecting this spreading remain poorly understood. This study investigated the relationship between neuronal activity and interneuronal transfer of α-synuclein, a Parkinson-associated protein, and elucidated mechanisms underlying this relationship. In a mouse model of α-synuclein brain spreading, hyperactivity augmented and hypoactivity attenuated protein transfer. Important features of neuronal hyperactivity reported here were an exacerbation of oxidative and nitrative reactions, pronounced accumulation of nitrated α-synuclein, and increased protein aggregation. Data also pointed to mitochondria as key targets and likely sources of reactive oxygen and nitrogen species within hyperactive neurons. Rescue experiments designed to counteract the increased burden of reactive oxygen species reversed hyperactivity-induced α-synuclein nitration, aggregation, and interneuronal transfer, providing first evidence of a causal link between these pathological effects of neuronal stimulation and indicating a mechanistic role of oxidant stress in hyperactivity-induced α-synuclein spreading.
The remote assessment of parkinsonism supporting the ongoing development of interventions in Gaucher disease
By onMutations in GBA which are causative of Gaucher disease in their biallelic form, are the most common genetic risk factor for Parkinson's disease (PD). The diagnosis of PD relies upon clinically defined motor features which appear after irreversible neurodegeneration. Prodromal symptoms of PD may provide a means to predict latent pathology, years before the onset of motor features. Previous work has reported prodromal features of PD in GBA mutation carriers, however this has been insufficiently sensitive to identify those that will develop PD. The Remote Assessment of Parkinsonism Supporting Ongoing Development of Interventions in Gaucher Disease (RAPSODI GD) study assesses a large cohort of GBA mutation carriers, to aid development of procedures for earlier diagnosis of PD.
Reconstitution of cargo-induced LC3 lipidation in mammalian selective autophagy
By onSelective autophagy is essential for maintaining cellular homeostasis. Using in vitro reconstitution, the authors explored the details of mitophagy initiation from autophagy receptor engagement through LC3 lipidation.
Disruption of lysosomal proteolysis in astrocytes facilitates midbrain proteostasis failure in an early-onset PD model
By onAccumulation of advanced glycation end products (AGEs) on biopolymers accompany cellular aging and drives poorly understood disease processes. Here, we studied how AGEs contribute to development of early on-set Parkinson’s Disease (PD) caused by loss-of-function of DJ1, a protein deglycase. In induced pluripotent stem cell (iPSC)-derived midbrain organoid models deficient for DJ1 activity, we find that lysosomal proteolysis is impaired, causing AGEs to accumulate, α-synuclein (α-syn) phosphorylation to increase, and proteins to aggregate. These processes are at least partly driven by astrocytes, as DJ1 loss reduces their capacity to provide metabolic support and triggers acquisition of a pro-inflammatory phenotype. Consistently, in co-cultures, we find that DJ1-expressing astrocytes are able to reverse the proteolysis deficits of DJ1 knockout midbrain neurons. In conclusion, astrocytes’ capacity to clear toxic damaged proteins is critical to preserve neuronal function and their dysfunction contributes to the neurodegeneration observed in PD.
Multi-ancestry genome-wide meta-analysis in Parkinson’s disease
By onAlthough over 90 independent risk variants have been identified for Parkinson’s disease using genome-wide association studies, all studies have been performed in just one population at the time. Here we performed the first large-scale multi-ancestry meta-analysis of Parkinson’s disease with 49,049 cases, 18,785 proxy cases, and 2,458,063 controls including individuals of European, East Asian, Latin American, and African ancestry. In a single joint meta-analysis, we identified 78 independent genome-wide significant loci including 12 potentially novel loci (MTF2, RP11-360P21.2, ADD1, SYBU, IRS2, USP8:RP11-562A8.5, PIGL, FASN, MYLK2, AJ006998.2, Y_RNA, PPP6R2) and finemapped 6 putative causal variants at 6 known PD loci. By combining our results with publicly available eQTL data, we identified 23 genes near these novel loci whose expression is associated with PD risk. This work lays the groundwork for future efforts aimed at identifying PD loci in non-European populations.
Regulatory imbalance between LRRK2 kinase, PPM1H phosphatase, and ARF6 GTPase disrupts the axonal transport of autophagosomes
By onThe authors found that LRRK2-hyperphosphorylated RABs disrupt the axonal transport of autophagosomes by perturbing the coordinated regulation of cytoplasmic dynein and kinesin motors.
Temporal landscape of mitochondrial proteostasis governed by the UPRmt
By onThe authors developed a functional proteomics framework, termed MitoPQ (Mitochondrial Proteostasis Quantification), to dissect the UPRmts role in maintaining proteostasis during stress.
Border-associated macrophages mediate the neuroinflammatory response in an alpha-synuclein model of Parkinson disease
By onBorder-associated macrophages (BAMs) are crucial in Parkinson's disease pathogenesis by initiating neuroinflammation, highlighting a potential target for therapeutic intervention.
Motor learning selectively strengthens cortical and striatal synapses of motor engram neurons
By onIn this study, Hwang, Roth, et al. find that motor learning recruits a population of engram neurons in the motor cortex that are reactivated during task performance. Motor learning leads to selective remodeling of dendritic spines and strengthening of outputs to the striatum of M1 engram neurons.
The SATB1-MIR22-GBA axis mediates glucocerebroside accumulation inducing a cellular senescence-like phenotype in dopaminergic neurons
By onStudy shows SATB1, MIR22HG, and GBA genes form a pathway in Parkinson's Disease. Dysregulation leads to GluCer accumulation, causing cellular senescence in dopaminergic neurons, potentially explaining neuroinflammation seen in PD and aging.
