Mitochondrial dysfunction induced by a post-translationally modified amyloid linked to a familial mutation in an alternative model of neurodegeneration

AbstractFamilial British dementia (FBD) is an early-onset non-amyloid-β (Aβ) cerebral amyloidosis that presents with severe cognitive decline and strikingly similar neuropathological features to those present in Alzheimer's disease (AD). FBD is associated with a T to A single nucleotide transition in the stop codon of a gene encoding BRI2, leading to the production of an elongated precursor protein. Furin-like proteolytic processing at its C-terminus releases a longer-than-normal 34 amino acid peptide, ABri, exhibiting amyloidogenic properties not seen in its 23 amino acid physiologic counterpart Bri1–23. Deposited ABri exhibits abundant post-translational pyroglutamate (pE) formation at the N-terminus, a feature seen in truncated forms of Aβ found in AD deposits, and co-exists with neurofibrillary tangles almost identical to those found in AD. We tested the impact of the FBD mutation alone and in conjunction with the pE post-translational modification on the structural properties and associated neurotoxicity of the ABri peptide. The presence of pE conferred to the ABri molecule enhanced hydrophobicity and accelerated aggregation/fibrillization properties. ABri pE was capable of triggering oxidative stress, loss of mitochondrial membrane potential and activation of caspase-mediated apoptotic mechanisms in neuronal cells, whereas homologous peptides lacking the elongated C-terminus and/or the N-terminal pE were unable to induce similar detrimental cellular pathways. The data indicate that the presence of N-terminal pE is not in itself sufficient to induce pathogenic changes in the physiologic Bri1–23 peptides but that its combination with the ABri mutation is critical for the molecular pathogenesis of FBD

Lutein and zeaxanthin intake during pregnancy and visual function in offspring at 11-12 years of age

Funding: This study has been funded by Instituto de Salud Carlos III through the projects “CP14/00108, PI16/00261 and PI21/00266” (Co-funded by European Regional Development Fund “A way to make Europe”). Jordi Julvez holds the Miguel Servet-II contract (CPII19/00015) awarded by the Instituto de Salud Carlos III (co-funded by the European Social Fund “Investing in your future”). This study was also funded by grants from Instituto de Salud Carlos III (Red INMA G03/176; CB06/02/0041; PI041436; PI081151 incl. FEDER funds; PI12/01890 incl. FEDER funds; CP13/00054 incl. FEDER funds; PI15/00118 incl. FEDER funds; CP16/00128 incl. FEDER funds; PI16/00118 incl. FEDER funds; PI16/00261 incl. FEDER funds; PI17/01340 incl. FEDER funds; PI18/00547 incl. FEDER funds), CIBERESP, Generalitat de Catalunya-CIRIT 1999SGR 00241, Generalitat de Catalunya-AGAUR (2009 SGR 501, 2014 SGR 822), Fundació La marató de TV3 (090430), Spanish Ministry of Economy and Competitiveness (SAF2012-32991 incl. FEDER funds), Agence Nationale de Securite Sanitaire de l’Alimentation de l’Environnement et du Travail (1262C0010; EST-2016 RF-21), EU Commission (261357, 308333, 603794 and 634453). We acknowledge support from the Spanish Ministry of Science and Innovation and the State Research Agency through the “Centro de Excelencia Severo Ochoa 2019-2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program.(1) Background: Lutein and zeaxanthin (L&Z) are essential dietary nutrients that are a crucial component of the human macula, contributing to visual functioning. They easily cross the placental barrier, so that retinal deposition commences during foetal development. This study aims to assess associations between maternal L&Z intake during pregnancy and offspring visual function at 11-12 years. (2) Methods: Using the Spanish INfancia y Medio Ambiente Project (INMA) Sabadell birth cohort, 431 mother-child pairs were analysed. L&Z data were obtained from food frequency questionnaires (FFQ) at week 12 and 32 of pregnancy, alongside other nutritional and sociodemographic covariates. Contrast vision (CS) and visual acuity (VA) were assessed using the automated Freiburg Acuity and Contrast Testing (FRACT) battery. Low CS and VA were defined as being below the 20th cohort centile. Associations were explored using multiple logistic regression. (3) Results: After controlling for potential confounders, L&Z intake during the 1st and 3rd trimester did not reveal any statistically significant association with either CS or VA in offspring at age 11/12 years. (4) Conclusions: No evidence of a long-term association between L&Z intake during pregnancy and visual function in offspring was found. Further larger long-term studies including blood L&Z levels are required to confirm this result.Publisher PDFPeer reviewe

The Gastrointestinal Microbiome and the Enteropathogenetic Syndromes

n/

Carbonic anhydrase inhibition selectively prevents amyloid b neurovascular mitochondrial toxicity

Mounting evidence suggests that mitochondrial dysfunction plays a causal role in the etiology and progression of Alzheimer’s disease (AD). We recently showed that the carbonic anhydrase inhibitor (CAI) methazolamide (MTZ) prevents amyloid b (Ab)-mediated onset of apoptosis in the mouse brain. In this study, we used MTZ and, for the first time, the analog CAI acetazolamide (ATZ) in neuronal and cerebral vascular cells challenged with Ab, to clarify their protective effects and mitochondrial molecular mechanism of action. The CAIs selectively inhibited mitochondrial dysfunction pathways induced by Ab, without affecting metabolic function. ATZ was effective at concentrations 10 times lower than MTZ. Both MTZ and ATZ prevented mitochondrial membrane depolarization and H2O2 generation, with no effects on intracellular pH or ATP production. Importantly, the drugs did not primarily affect calcium homeostasis. This work suggests a new role for carbonic anhydrases (CAs) in the Ab-induced mitochondrial toxicity associated with AD and cerebral amyloid angiopathy (CAA), and paves the way to AD clinical trials for CAIs, FDA-approved drugs with a well-known profile of brain delivery

Brainstem NTCP and dose constraints for carbon ion RT—Application and translation from Japanese to European RBE-weighted dose

Background and Purpose: The Italian National Center of Oncological Hadrontherapy (CNAO) has applied dose constraints for carbon ion RT (CIRT) as defined by Japan’s National Institute of Radiological Sciences (NIRS). However, these institutions use different models to predict the relative biological effectiveness (RBE). CNAO applies the Local Effect Model I (LEM I), which in most clinical situations predicts higher RBE than NIRS’s Microdosimetric Kinetic Model (MKM). Equal constraints therefore become more restrictive at CNAO. Tolerance doses for the brainstem have not been validated for LEM I-weighted dose (DLEM I). However, brainstem constraints and a Normal Tissue Complication Probability (NTCP) model were recently reported for MKM-weighted dose (DMKM), showing that a constraint relaxation to DMKM|0.7 cm3 <30 Gy (RBE) and DMKM|0.1 cm3 <40 Gy (RBE) was feasible. The aim of this work was to evaluate the brainstem NTCP associated with CNAO’s current clinical practice and to propose new brainstem constraints for LEM I-optimized CIRT at CNAO. Material and Methods: We reproduced the absorbed dose of 30 representative patient treatment plans from CNAO. Subsequently, we calculated both DLEM I and DMKM, and the relationship between DMKM and DLEM I for various brainstem dose metrics was analyzed. Furthermore, the NTCP model developed for DMKM was applied to estimate the NTCPs of the delivered plans. Results: The translation of CNAO treatment plans to DMKM confirmed that the former CNAO constraints were conservative compared with DMKM constraints. Estimated NTCPs were 0% for all but one case, in which the NTCP was 2%. The relationship DMKM/DLEM I could be described by a quadratic regression model which revealed that the validated DMKM constraints corresponded to DLEM I|0.7 cm3 <41 Gy (RBE) (95% CI, 38–44 Gy (RBE)) and DLEM I|0.1 cm3 <49 Gy (RBE) (95% CI, 46–52 Gy (RBE)). Conclusion: Our study demonstrates that RBE-weighted dose translation is of crucial importance in order to exchange experience and thus harmonize CIRT treatments globally. To mitigate uncertainties involved, we propose to use the lower bound of the 95% CI of the translation estimates, i.e., DLEM I|0.7 cm3 <38 Gy (RBE) and DLEM I|0.1 cm3 <46 Gy (RBE) as brainstem dose constraints for 16 fraction CIRT treatments optimized with LEM I.publishedVersio

Long-term Effect of Vasodilator Therapy in Pulmonary Hypertension due to COPD: A Retrospective Analysis

Purpose: Pulmonary hypertension (PH) due to COPD has dismal prognosis. We reviewed the long-term effect of PH-target therapy in severe PH-COPD. Method: Patients attending our PH-clinic were reviewed for PH-COPD receiving PH-target therapy. Baseline characteristics, death/transplantation until 2014, therapy, NYHA functional class, 6min walk distance (6MWD) and oxygen saturation (SpO2) at baseline, 3, 6, 12 and 24months were analysed. Results: Of 48 PH-COPD identified 21 were excluded (insufficient data, comorbidity). 27 patients (7 females, 21 smokers, 23 emphysema) with median (quartiles) baseline age 70 (60; 76)years, FEV1 60 (46; 78)%, FEV1/FVC 57 (51; 64)%, DLCO 42 (36; 59)%, mean pulmonary artery pressure 39 (32;44) mmHg under inhaled iloprost (10), subcutaneous prostanoids (2), intravenous prostanoids (3), endothelin receptor antagonists (15) and phosphodiesterase-5-inhibitors (25) were included. Under therapy, NYHA functional class improved from 3.5 (3; 4) to 3 (2; 4) after 3months and 3 (2; 3.5) after 6months (p=.02 and .008). The 6MWD improved from 373 (236; 452) to 395 (339; 472), 414 (285; 492) and 396 (308; 497)m at 3, 6 and 12months (p=.005, .006 and .011) with unchanged resting-SpO2 but decreased peak-exercise SpO2. During median follow-up of 5.9 (2.3; 8.4) years, 10 died, 2 were transplanted and 2 were lost to follow-up. Transplant-free survival at 1,2,3years was 92,69,54% and was similar for GOLD stages 1-4, but worse for patients with mPAP ≥40mmHg (p=.026), 6MWD <370m (p=0.008), resting SpO2 <92% (p=0.02) and peak-walk SpO2 <87% (p=0.012). Conclusion: PH-target vasodilator therapy improved NYHA functional class and 6MWD up to one year in highly selected patients with severe PH-COPD. Poor exercise capacity, low SpO2 and high mean pulmonary artery pressure at baseline but not airflow obstruction were associated with unfavourable outcome