This study demonstrates the application of quantitative elemental bio-imaging for the determination of the distribution Cu, Mn, Fe and Zn in Parkinsonism mouse model brains. Elevated concentrations of these metals within the substantia nigra (SN) are suspected to play a role on the development of Parkinson's disease. Elemental bio-imaging employs laser ablation inductively coupled mass spectrometry (LA-ICP-MS) to construct images of trace element distribution. Quantitative data was produced by ablating the standard tissue sections and recording the mean signal intensity calibrated against multi level matrix matched tissue standards. The concentrations of Fe within the substantia nigra of the lesioned animals increased significantly when compared against control animals.Furthermore, the data was compared against solution nebulisation ICP-MS in which the whole substantia nigra was excised. The trends were the same for both methods; however the elemental bioimaging method returned significantly higher concentrations. This was caused by dilution from inclusion of surrounding tissue of the SN during the excision procedure.
Atlases depicting molecular and functional features of the brain are becoming an integral part of modern neuroscience. In this study we used laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS) to quantitatively measure iron (Fe), copper (Cu), and zinc (Zn) levels in a serially sectioned C57BL/6 mouse brain (cerebrum and brainstem). Forty-six sections were analyzed in a single experiment of approximately 158 h in duration. We constructed a 46-plate reference atlas by aligning quantified images of metal distribution with corresponding coronal sections from the Allen Mouse Brain Reference Atlas. The 46 plates were also used to construct three-dimensional models of Fe, Cu, and Zn distribution. This atlas represents the first reconstruction of quantitative trace metal distribution through the brain by LA-ICPMS and will facilitate the study of trace metals in the brain and help to elucidate their role in neurobiology.
Elevation of both neuronal iron and nitric oxide (NO) in the substantia nigra are associated with Parkinson's disease (PD) pathogenesis. We reported previously that the Alzheimer-associated -amyloid precursor protein (APP) facilitates neuronal iron export. Here we report markedly decreased APP expression in dopaminergic neurons of human PD nigra and that APP Ϫ/Ϫ mice develop iron-dependent nigral cell loss. Conversely, APP-overexpressing mice are protected in the MPTP PD model. NO suppresses APP translation in mouse MPTP models, explaining how elevated NO causes iron-dependent neurodegeneration in PD.
Aberrant posttranslational modifications (PTMs) of proteins, namely phosphorylation, induce abnormalities in the biological properties of recipient proteins, underlying neurological diseases including Parkinson's disease (PD). Genome-wide studies link genes encoding α-synuclein (α-Syn) and Tau as two of the most important in the genesis of PD. Although several kinases are known to phosphorylate α-Syn and Tau, we focused our analysis on GSK-3β because of its accepted role in phosphorylating Tau and to increasing evidence supporting a strong biophysical relationship between α-Syn and Tau in PD. Therefore, we investigated transgenic mice, which express a point mutant (S9A) of human GSK-3β. GSK-3β-S9A is capable of activation through endogenous natural signaling events, yet is unable to become inactivated through phosphorylation at serine-9. We used behavioral, biochemical, and in vitro analysis to assess the contributions of GSK-3β to both α-Syn and Tau phosphorylation. Behavioral studies revealed progressive age-dependent impairment of motor function, accompanied by loss of tyrosine hydroxylase-positive (TH+ DA-neurons) neurons and dopamine production in the oldest age group. Magnetic resonance imaging revealed deterioration of the substantia nigra in aged mice, a characteristic feature of PD patients. At the molecular level, kinase-active p-GSK-3β-Y216 was seen at all ages throughout the brain, yet elevated levels of p-α-Syn-S129 and p-Tau (S396/404) were found to increase with age exclusively in TH+ DA-neurons of the midbrain. p-GSK-3β-Y216 colocalized with p-Tau and p-α-Syn-S129. In vitro kinase assays showed that recombinant human GSK-3β directly phosphorylated α-Syn at a single site, Ser129, in addition to its known ability to phosphorylate Tau. Moreover, α-Syn and Tau together cooperated with one another to increase the magnitude or rate of phosphorylation of the other by GSK-3β. Together, these data establish a novel upstream role for GSK-3β as one of several kinases associated with PTMs of key proteins known to be causal in PD.
Telehealth is an important tool utilized to provide remote clinical care and has increased in prevalence during the coronavirus disease of 2019 (COVID-19) pandemic. It allows providers to conduct safe, timely, and high-quality ambulatory care for patients without increasing risk of disease exposure for both parties. Major organizations including the Centers for Disease Control and Prevention and American College of Obstetrics and Gynecology have released recommendations encouraging the use of telehealth systems for patient care. In obstetrics and gynecology, practice of telehealth has not been commonplace and no practical procedural guidelines have been published. The authors have created such guidelines for use of telehealth in a moderate-risk academic generalist practice in response to the COVID-19 pandemic. This document highlights the process to determine which obstetrics and gynecology patients are candidates for telehealth, the frequency of follow-up, and the technical aspects of designing and delivering a de novo telehealth system. The guidelines were vital in providing structure amid a sudden transition in an academic setting while ensuring patient and provider safety.
Three dimensional maps of iron (Fe), zinc (Zn), copper (Cu), manganese (Mn) and phosphorous (P) in a 6-hydroxydopamine (6-OHDA) lesioned mouse brain were constructed employing a novel quantitative laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) imaging method known as elemental bio-imaging. The 3D maps were produced by ablating serial consecutive sections taken from the same animal. Each section was quantified against tissue standards resulting in a three dimensional map that represents the variation of trace element concentrations of the mouse brain in the area surrounding the substantia nigra (SN). Damage caused by the needle or the toxin did not alter the distribution of Zn, and Cu but significantly altered Fe in and around the SN and both Mn and Fe around the needle track. A 20% increase in nigral Fe concentration was observed within the lesioned hemisphere. This technique clearly shows the natural heterogeneous distributions of these elements throughout the brain and the perturbations that occur following trauma or intoxication. The method may applied to three-dimensional modelling of trace elements in a wide range of tissue samples.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.