Ferroptosis in Parkinson's disease: Molecular mechanisms and therapeutic potential

Parkinson's Disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra (SN), leading to motor and non-motor symptoms. While the exact mechanisms remain complex and multifaceted, several molecular pathways have been implicated in PD pathology, including accumulation of misfolded proteins, impaired mitochondrial function, oxidative stress, inflammation, elevated iron levels, etc. Overall, PD's molecular mechanisms involve a complex interplay between genetic, environmental, and cellular factors that disrupt cellular homeostasis, and ultimately lead to the degeneration of dopaminergic neurons. Recently, emerging evidence highlights ferroptosis, an iron-dependent non-apoptotic cell death process, as a pivotal player in the advancement of PD. Notably, oligomeric α-synuclein (α-syn) generates reactive oxygen species (ROS) and lipid peroxides within cellular membranes, potentially triggering ferroptosis. The loss of dopamine, a hallmark of PD, could predispose neurons to ferroptotic vulnerability. This unique form of cell demise unveils fresh insights into PD pathogenesis, necessitating an exploration of the molecular intricacies connecting ferroptosis and PD progression. In this review, the molecular and regulatory mechanisms of ferroptosis and their connection with the pathological processes of PD have been systematically summarized. Furthermore, the features of ferroptosis in PD animal models and clinical trials targeting ferroptosis as a therapeutic approach in PD patients' management are scrutinized.

[Predictive value of NT-proBNP on admission on left ventricular ejection fraction and in-patients major adverse cardiac and cerebrovascular events in hospitalized patients with unstable angina]

Objective: To explore the predictive value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) on admission on left ventricular ejection fraction (LVEF) and the in-hospital major adverse cardiac and cerebrovascular events (MACCE) in hospitalized patients with unstable angina (UA). Methods: Data of 2 972 consecutive hospitalized patients with UA in Beijing Friendship Hospital from January 2013 to September 2017 were retrospective analyzed. Patients were divided into 4 groups according to the level of NT-proBNP on admission: 733 cases with NT-proBNP lower than 61 ng/L, 749 cases with NT-proBNP between 61 and 133 ng/L, 747 cases with NT-proBNP between 133 and 326 ng/L, and 743 cases with NT-proBNP higher than 326 ng/L. LVEF and in-hospital MACCE were compared among 4 groups and the predictive value of NT-proBNP on admission on LVEF and in-hospital MACCE was determined by multiple logistical regression analysis. Results: LVEF value became lower with increasing on admission NT-proBNP value ((68.4±4.8)%, (68.2±5.2)%, (67.2±6.7)% and (62.6±10.4)%, F=77.98, P<0.01), while in-hospital MACCE was higher with increasing on admission NT-proBNP value (3.4% (25/733), 3.5% (26/749), 5.5% (41/747) and 7.3% (54/743), χ(2)=16.23, P<0.01) in NT-proBNP lower than 61 ng/L, NT-proBNP between 61 and 133 ng/L, NT-proBNP between 133 and 326 ng/L, and NT-proBNP higher than 326 ng/L group. Multiple logistic regression analysis showed that on admission NT-proBNP was an independent predictor for LVEF<50% (Exp(β)=5.875, 95%CI 3.382-10.207, P<0.001), but not predictor for in-hospital MACCE (Exp(β)=0.783, 95%CI 0.400-1.996, P=0.783). Conclusion: The on admission NT-proBNP level is an independent predictor of left ventricular systolic dysfunction (LVEF<50%), but not an independent predictor of total in-hospital MACCE in hospitalized patients with UA.

Progressive Nonfluent Aphasia: Language, Cognitive, and PET Measures Contrasted with Probable Alzheimer's Disease

The purpose of this study was to compare the language and cognitive profiles of four progressive nonfluent aphasia (PNFA) patients with 25 probable Alzheimer's disease (pAD) patients, and to identify the distinct cortical defects associated with cognitive deficits in PNFA using positron emission tomography (PET). Longitudinal observations of PNFA patients revealed progressively telegraphic speech and writing and a gradual deterioration of sentence comprehension, but memory and visual functioning were relatively preserved. Direct contrast with PAD patients revealed that PNFA patients are significantly impaired on grammatical phrase structure aspects of sentence comprehension and expression, phonemic judgments, repetition, and digit span, but not on other cognitive measures. PET studies of PNFA revealed reduced cortical activity throughout the left hemisphere. In addition, there was a prominent defect in left superior and middle temporal and inferior frontal regions of PNFA patients that differed significantly from the distribution of regional cerebral dysfunction in pAD. We conclude that PNFA is associated with a distinct profile of language and cognitive difficulty, and that this pattern of impairment is related to cortical dysfunction in a specific distribution of the left hemisphere.

Response of Tall Fescue Genotypes to a New Strain of Brome mosaic virus

Brome mosaic virus (BMV) infects many different species within the Poaceae family. A new strain of BMV, named F-BMV, was identified in a tall fescue (Festuca arundinacea Schreb.) plant. Here, we report the identification and characterization of tall fescue plants resistant to F-BMV, and the effects of F-BMV infection on their growth and development. Susceptible plants infected with F-BMV produced 40% fewer tillers and 42% less dry matter compared with virus-resistant plants in a greenhouse study. In the field, susceptible plants infected with F-BMV produced 25% fewer tillers, 36% less dry matter, 10% less plant height, and 40% lower seed yield compared with virus-resistant plants. In a field evaluation of a tall fescue mapping population, the virus symptom scores were negatively correlated with production of dry matter (r = -0.55), plant height (r = -0.55), and seed yield (r = -0.33). Thus, F-BMV has the potential to cause significant economic damage to susceptible tall fescue plants. These results indicate that the virus can present a serious challenge for long-term maintenance of valuable plant materials. A survey of tall fescue plants from Arkansas, Oklahoma, and Oregon indicated that the prevalence F-BMV in the field was very low.

Presence of Brome mosaic virus in Barley Guttation Fluid and Its Association with Localized Cell Death Response

ABSTRACT Water exits from inside the leaf through transpiration or guttation. Under conditions to promote guttation, surface fluid (guttation fluid) from Brome mosaic virus (BMV)-infected barley, wheat, and maize plants was analyzed for the presence of the virus by biological and serological assays. We also investigated the route by which BMV exited infected cells to the intercellular space of the barley leaf. BMV was detected in guttation fluid from systemically infected barley leaves when the initial viral symptoms were observed on these leaves. The virus was also detected in guttation fluid from systemically infected wheat leaves, but not in maize leaves showing either systemic necrosis or chlorotic streaks. Interestingly, in BMV-infected barley leaves, but not in maize leaves showing chlorotic streaks, cell death occurred within and adjacent to veins. Staining of xylem and phloem networks in infected barley leaves with fluorescent dyes showed that xylem, and to a lesser extent phloem, were severely damaged and thus became leaky for dye transport. No such damage was observed in BMV-infected maize leaves showing chlorotic streaks. We propose that in infected barley leaves, BMV exits from damaged vein cells (especially the xylem elements), accumulates in intercellular spaces, and then reaches the surface of the leaves through stomata during guttation or transpiration. In nature, BMV may be carried to adjacent plants and cause infection by movement of vertebrate and invertebrate vectors among infected plants exuding guttation fluid.

Progressive peripheral agraphia

We describe RW, a patient who presented with writing difficulty that deteriorated over time. While her graphemes were typically legible, her writing was extremely slow, and her letters were written in an inconsistent and heterogeneous manner (e.g. each "a" in the word "banana" was produced in a different way). Her mental imagery of letters was impoverished, and she also produced allographic errors in her writing. She had some spelling errors as well, but many of these were due to omissions, perseverations, and motor operations. A positron emission tomography scan demonstrated superior parietal occipital and superior frontal defects that were more evident on the left than the right. Our observations are consistent with the hypothesis that RW has a deficit retrieving physical letter forms as manifested by her heterogeneous and slow production of letter forms. This disruption of grapheme retrieval is associated with interruption of a superior frontal-parietal system in the left hemisphere.

Hippocampal cell density and subcortical metabolism in temporal lobe epilepsy

PURPOSE

Correlations between hippocampal cell density and subcortical metabolism in patients with temporal lobe epilepsy (TLE) were studied to explore possible links between subcortical function and the regulation of hippocampal excitability.

METHODS

Resected hippocampal cell densities were correlated with cortical and subcortical regional cerebral metabolic rate for glucose (CMRglu), as measured by [18F]-fluorodeoxyglucose positron emission tomography (18-FDG-PET), in 39 patients with intractable TLE who underwent anterior temporal lobectomy (ATL). CMRglu was measured ipsilateral and contralateral to the resected temporal lobe. Linear regression techniques were used for statistical analysis.

RESULTS

Hilar cell densities correlated positively and significantly with CMRglu in the bilateral thalamus, putamen and globus pallidus, and the ipsilateral caudate. Dentate granule cell densities correlated positively and significantly with CMRglu in the bilateral thalamus and putamen. There was no significant correlation between cell densities and CMRglu in any cortical region, including the hippocampus.

CONCLUSIONS

We postulate that hippocampal cell loss results in decreased efferent synaptic activity to the thalamus and basal ganglia, causing decreased neuronal activity in these structures with consequent hypometabolism. This synaptic activity has a significant bilateral component. Subcortical hypometabolism in patients with TLE may reinforce the epileptogenic potential of mesial temporal lobe discharges.

Cognitive, neuroimaging, and pathological studies in a patient with Pick's disease

We conducted cognitive, imaging, and neuropathological studies on a patient with Pick's disease. The patient was impaired at interpreting sentences with complex grammatical constructions, differing significantly from control subjects and patients with Alzheimer's disease (AD). Evaluation of regional brain functioning at rest, with positron emission tomography, revealed reduced left frontal activity compared with control subjects and AD patients. Autopsy demonstrated the classic pathology of Pick's disease, including massive neuron loss and gliosis in the frontal and cingulate cortex as well as numerous tau-positive hippocampal Pick bodies. The abnormal tau proteins were phosphorylated at the same amino acid residues as AD paired helical filament tau (PHFtau), but they exhibited a unique migration profile on western blot. Our observations support the hypothesis that a distinct variety of hyperphosphorylated tau in Pick's disease compromises the long-term viability of selectively vulnerable populations of neurons in frontal cortices that contribute to sentence processing.

Use of positron emission tomography and evoked potentials in the detection of cortical afferents from the gastrointestinal tract

OBJECTIVE

Positron emission tomography permits precision identification of the cerebral regions involved in physiologic functions. As the cerebral localization for visceral sensation has not been identified, our aim was to examine the cerebral viscerotopic representation for rectal sensation.

METHODS

Cerebral-evoked potentials were measured in five healthy volunteers who underwent rectal balloon distension. Simultaneously, cerebral blood flow was measured using positron emission tomography with 15H2O.

RESULTS

A cerebral-evoked potential occurred with rectal balloon distension. An increase in cerebral blood flow was noted in the pre- and postcentral gyrus and the thalamus.

CONCLUSION

The techniques for measuring cerebral-evoked potentials and cortical blood flow are useful in the delineation of the cerebral regions subserving visceral sensation.

Nla and Nlb of peanut stripe potyvirus are present in the nucleus of infected cells, but do not form inclusions

We investigated, by immunological and gene-fusion methods, whether the failure of peanut stripe potyvirus (PStV)-encoded nuclear inclusion proteins a (Nla) and b (Nlb) to form nuclear inclusions is due to the lack of their in vivo accumulation or the inability of one or both proteins to be transported into the nucleus Nla domains (Nla-VPg and Nla-proteinase), full-length Nlb, and full-length cylindrical inclusion (CI) protein of PStV were cloned, expressed in Escherichia coli, and used for antisera production. Immunoblot analysis of accumulation of Nla, Nlb, and CI in time course experiments revealed that they accumulated to similar levels in PStV-infected Nicotiana benthamiana. In immunocytochemical studies with electron microscopy, antiserum against Nla-VPg, Nla-Pro, and Nlb specifically labeled Nla and Nlb proteins throughout the nuclei of PStV-infected cells, in the absence of nuclear inclusions. Translational fusions were made between Nla and Nlb to either the green fluorescence protein or the beta-glucuronidase in vectors for transient gene expression or stable expression in transgenic plants respectively. Fusion proteins containing Nla accumulated in the nucleus, whereas fusion proteins containing Nlb accumulated in a punctate pattern in the cytoplasm. These data indicate that at least Nla possesses a nuclear localization signal.

Enhanced cytochemical detection of viral proteins and RNAs using double-sided labeling and light microscopy

We have developed a double-sided labeling technique for detecting viral proteins or RNAs in plastic-embedded leaf tissue by immunocytochemistry or in situ hybridization, respectively, and light microscopy. The signal from the target was enhanced by double-sided labeling when compared with single-sided labeling because sections were submerged in labeling solutions with both sides accessible to antibodies or complementary RNAs. The additional label was visible during microscopic analysis. Background signal was decreased since the tissue was probed and washed under conditions where folds and creases in the tissue were minimized. This technique uses the same equipment and chemicals as for single-sided labeling, and thus adjustments for reagent expenditures are not necessary. The procedure should be applicable to animal and plant tissue.

Tomaculous neuropathy in chromosome 1 Charcot-Marie-Tooth syndrome

We performed morphological and immunohistochemical studies on sural nerve biopsies from two members of a Charcot-Marie-Tooth type 1B family, in which a mutation of the P0 gene on chromosome 1 had been found. Biopsies showed a tomaculous neuropathy with loss of myelinated fibers and frequent small onion bulbs. Immunofluorescence with antibodies to P0 showed this protein to be present in tomaculous and non-tomaculous areas of the myelin sheath. The severity of the myelin abnormalities suggests that in this family Charcot-Marie-Tooth disease may result from a generalized disturbance of Schwann cells as a result of an abnormal P0 protein.

Vasculitic neuropathy in a patient with cryoglobulinemia and anti-MAG IGM monoclonal gammopathy

A patient with sensorimotor mononeuritis multiplex had a type II cryoglobulin with an IgM kappa M-protein that appeared to contain monoclonal anti-MAG antibodies of the same isotype. A sural nerve biopsy demonstrated necrotizing arteritis and features of both axonal degeneration and demyelination. IgM kappa and C3 deposits were present on the myelin sheath of some residual nerve fibers. The findings suggest that the anti-MAG antibodies contributed to the myelin damage, while cryoprecipitates may have caused the vasculitis and axonal degeneration.