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The ability to use blood to predict the outcomes of Parkinson’s disease, including disease progression and cognitive and motor complications, would be of significant clinical value. We undertook bulk RNA sequencing from the caudate and putamen of postmortem Parkinson’s disease ( n  = 35) and control ( n  = 40) striatum, and compared molecular profiles with clinical features and bulk RNA sequencing data obtained from antemortem peripheral blood. Cognitive and motor complications of Parkinson’s disease were associated with molecular changes in the caudate (stress response) and putamen (endothelial pathways) respectively. Later and earlier-onset Parkinson’s disease were molecularly distinct, and disease duration was associated with changes in caudate (oligodendrocyte development) and putamen (cellular senescence), respectively. Transcriptome patterns in the postmortem Parkinson’s disease brain were also evident in antemortem peripheral blood, and correlated with clinical features of the disease. Together, these findings identify molecular signatures in Parkinson’s disease patients’ brain and blood of potential pathophysiologic and prognostic importance. Understanding molecular processes behind variable clinical features of Parkinson’s disease is valuable. Distinct molecular patterns in the brains, reflected in the blood, reveal mechanisms linked to clinical diversity in cognitive and motor decline.

A common single-nucleotide polymorphism (SNP) in the human brain-derived neurotrophic factor ( BDNF ) gene results in a Val66Met substitution in the BDNF prodomain region. This SNP is associated with alterations in memory and with enhanced risk to develop depression and anxiety disorders in humans. Here we show that the isolated BDNF prodomain is detected in the hippocampus and that it can be secreted from neurons in an activity-dependent manner. Using nuclear magnetic resonance spectroscopy and circular dichroism, we find that the prodomain is intrinsically disordered, and the Val66Met substitution induces structural changes. Surprisingly, application of Met66 (but not Val66) BDNF prodomain induces acute growth cone retraction and a decrease in Rac activity in hippocampal neurons. Expression of p75 NTR and differential engagement of the Met66 prodomain to the SorCS2 receptor are required for this effect. These results identify the Met66 prodomain as a new active ligand, which modulates neuronal morphology. The Val66Met single-nucleotide polymorphism in the BDNF gene is implicated in neuropsychiatric disorders. Anastasia et al. show that this polymorphism results in structural changes in the brain-derived neurotrophic factor prodomain, and growth cone retraction in the hippocampal neurons.

Pericyte and vascular smooth muscle cell (SMC) recruitment to the developing vasculature is an important step in blood vessel maturation. Brain-derived neurotrophic factor (BDNF), expressed by endothelial cells, activates the receptor tyrosine kinase TrkB to stabilize the cardiac microvasculature in the perinatal period. However, the effects of the BDNF/TrkB signaling on pericytes/SMCs and the mechanisms downstream of TrkB that promote vessel maturation are unknown. To confirm the involvement of TrkB in vessel maturation, we evaluated TrkB deficient (trkb (-/-)) embryos and observed severe cardiac vascular abnormalities leading to lethality in late gestation to early prenatal life. Ultrastructural analysis demonstrates that trkb(-/-) embryos exhibit defects in endothelial cell integrity and perivascular edema. As TrkB is selectively expressed by pericytes and SMCs in the developing cardiac vasculature, we generated mice deficient in TrkB in these cells. Mice with TrkB deficiency in perivascular cells exhibit reduced pericyte/SMC coverage of the cardiac microvasculature, abnormal endothelial cell ultrastructure, and increased vascular permeability. To dissect biological actions and the signaling pathways downstream of TrkB in pericytes/SMCs, human umbilical SMCs were treated with BDNF. This induced membranous protrusions and cell migration, events dependent on myosin light chain phosphorylation. Moreover, inhibition of Rho GTPase and the Rho-associated protein kinase (ROCK) prevented membrane protrusion and myosin light chain phosphorylation in response to BDNF. These results suggest an important role for BDNF in regulating migration of TrkB-expressing pericytes/SMCs to promote cardiac blood vessel ensheathment and functional integrity during development.

Post-stroke movement disorders occur in up to 4% of stroke patients. The movements can be complex and difficult to classify, which presents challenges when attempting to understand the clinical phenomenology and provide appropriate treatment. We present a 64-year-old male with an unusual movement in the arm contralateral to his ischemic stroke. The primary feature of the movement was an involuntary elevation of the arm, occurring only when he was walking. The differential diagnosis includes dystonia, spontaneous arm levitation, synkinesis, and spasticity. We discuss each of these diagnostic possibilities in detail.

Background: Post-stroke movement disorders occur in up to 4% of stroke patients. The movements can be complex and difficult to classify, which presents challenges when attempting to understand the clinical phenomenology and provide appropriate treatment.Case Report: We present a 64-year-old male with an unusual movement in the arm contralateral to his ischemic stroke. The primary feature of the movement was an involuntary elevation of the arm, occurring only when he was walking.Discussion: The differential diagnosis includes dystonia, spontaneous arm levitation, synkinesis, and spasticity.We discuss each of these diagnostic possibilities in detail.

Nature Communications 4: Article number: 2490 (2013); Published: 18 September 2013; Updated: 8 April 2014. The glutaraldehyde fixation method used in this Article was previously published by Dieni et al. to detect BDNF propeptide, and should have been cited in the first paragraph of the Results section as follows: ‘However, glutaraldehyde fixation of proteins to the transfer membranes following sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS–PAGE) according to Dieni et al.

Transient receptor potential channel 1 (TRPC1; a cation channel activated by store depletion and/or through an intracellular messenger) is expressed in a variety of tissues, including the brain. To study the physiological function of TRPC1, we investigated the role of endogenously expressed TRPC1 in glutamate-induced cell death, using the murine hippocampal cell line HT22. Knocking down TRPC1 mRNA using TRPC1-shRNA or blocking of TRPC channels using 2-APB (≥200 μM) robustly attenuated glutamate-induced cell death after 24 h of incubation with 5 mM glutamate. Glutamate toxicity in HT22 cells seems to involve metabotropic glutamate receptor mGluR5 since MPEP (2-methyl-6-(phenylethynyl)-pyridine), an mGluR5 antagonist (≥100 μM), abrogated glutamate toxicity. Furthermore, a direct activation of mGluR5 by CHPG [(RS)-chloro-5-hydroxyphenylglycine; 100 μM or 300 μM] promoted HT22 cell death. TRPC1 knock-down markedly reduced CHPG-induced cell death. These observations suggest that glutamate-induced cell death in HT22 cells activates mGluR5 receptors, which significantly increases Ca 2+ influx through TRPC1 channels. TRPC1 knock-down prevented glutamate- and CHPG-induced cell death, suggesting that glutamate-induced toxicity in HT22 cells is mediated through TRPC1 channels and an mGluR5-dependent pathway. Together, this work provides evidence for a novel receptor activation pathway of TRPC1 in glutamate-induced toxicity.

The neuronal RNA-binding protein (RBP) family nELAVL regulates key neuronal processes by binding directly to target RNA transcripts. In this study, we demonstrate that ELAVL3 is the predominant nELAVL paralog expressed in D1 and D2 medium spiny neurons of the striatum. To investigate its function, we developed ELAVL3 cTag-crosslinking and immunoprecipitation (CLIP) to generate RBP-RNA interaction maps from these neurons. By integrating data from ELAVL3-cTag and Elavl3 knockout mice, we identified distinct regulatory effects of ELAVL3 on alternative splicing of its target transcripts. Notably, ELAVL3 modulates splicing of transcripts encoding proteins critical for glutamate and dopamine receptor signaling. These findings underscore the role of ELAVL3 in RNA-mediated regulation of molecular pathways essential for medium spiny neuron function in the striatum.Competing Interest StatementThe authors have declared no competing interest.