Pattern and progression of cognitive decline in Alzheimer's disease: role of premorbid intelligence and ApoE genotype

BACKGROUND/AIMS

Because of controversial results across studies, we evaluated the predictive value of premorbid intelligence and the apolipoprotein E (ApoE) genotype on baseline and progression of cognitive performance in Alzheimer's disease (AD).

METHODS

Eighty-five mild AD cases, ApoE genotyped and included in a longitudinal cliniconeuropsychological-genetic study, underwent a premorbid intelligence test and up to 11 (average 5) neuropsychological assessments. We applied linear- and logistic-regression models for cross-sectional data and mixed models for longitudinal ones.

RESULTS

Higher premorbid intelligence was associated with higher global, executive and memory performance, while the ApoE epsilon 4 allele was specifically related to poorer memory performance. The premorbid intelligence-ApoE epsilon 4/epsilon 4 interaction was significant, with higher premorbid intelligence scores reducing the detrimental effect of ApoE epsilon 4 homozygosity on memory performance. Higher premorbid intelligence, but not the ApoE epsilon 4 allele, was related to faster memory deficit progression.

CONCLUSION

The association of higher premorbid intelligence with better baseline cognitive performance and faster memory decline, as well as its interaction with the ApoE genotype, strengthens the role of cognitive reserve in shaping the disease's clinical expression. Our findings confirm that the epsilon 4 allele affects memory deficit at baseline but does not exert any influence on the rate of cognitive decline.

Targeting SARS-CoV-2 by synthetic dual-acting thiol compounds that inhibit Spike/ACE2 interaction and viral protein production

The SARS-CoV-2 life cycle is strictly dependent on the environmental redox state that influences both virus entry and replication. A reducing environment impairs the binding of the spike protein (S) to the angiotensin-converting enzyme 2 receptor (ACE2), while a highly oxidizing environment is thought to favor S interaction with ACE2. Moreover, SARS-CoV-2 interferes with redox homeostasis in infected cells to promote the oxidative folding of its own proteins. Here we demonstrate that synthetic low molecular weight (LMW) monothiol and dithiol compounds induce a redox switch in the S protein receptor binding domain (RBD) toward a more reduced state. Reactive cysteine residue profiling revealed that all the disulfides present in RBD are targets of the thiol compounds. The reduction of disulfides in RBD decreases the binding to ACE2 in a cell-free system as demonstrated by enzyme-linked immunosorbent and surface plasmon resonance (SPR) assays. Moreover, LMW thiols interfere with protein oxidative folding and the production of newly synthesized polypeptides in HEK293 cells expressing the S1 and RBD domain, respectively. Based on these results, we hypothesize that these thiol compounds impair both the binding of S protein to its cellular receptor during the early stage of viral infection, as well as viral protein folding/maturation and thus the formation of new viral mature particles. Indeed, all the tested molecules, although at different concentrations, efficiently inhibit both SARS-CoV-2 entry and replication in Vero E6 cells. LMW thiols may represent innovative anti-SARS-CoV-2 therapeutics acting directly on viral targets and indirectly by inhibiting cellular functions mandatory for viral replication.

Myelin basic protein recovery during PKU mice lifespan and the potential role of microRNAs on its regulation

Untreated phenylketonuria (PKU) patients and PKU animal models show hypomyelination in the central nervous system and white matter damages, which are accompanied by myelin basic protein (MBP) impairment. Despite many assumptions, the primary explanation of the mentioned cerebral outcomes remains elusive. In this study, MBP protein and mRNA expression on brains of wild type (WT) and phenylketonuric (ENU2) mice were analyzed throughout mice lifespan (14-60-180-270-360-540 post-natal days, PND). The results confirmed the low MBP expression at first PND times, while revealed an unprecedented progressive MBP protein expression recovery in aged ENU2 mice. Unexpectedly, unaltered MBP mRNA expression between WT and ENU2 was always observed. Additionally, for the same time intervals, a significant decrease of the phenylalanine concentration in the peripheral blood and brain of ENU2 mice was detected, to date, for the first time. In this scenario, a translational hindrance of MBP during initial and late cerebral development in ENU2 mice was hypothesized, leading to the execution of a microRNA microarray analysis on 60 PND brains, which was followed by a proteomic assay on 60 and 360 PND brains in order to validate in silico miRNA-target predictions. Taken together, miR-218 - 1-3p, miR - 1231-3p and miR-217-5p were considered as the most impactful microRNAs, since a downregulation of their potential targets (MAG, CNTNAP2 and ANLN, respectively) can indirectly lead to a low MBP protein expression. These miRNAs, in addition, follow an opposite expression trend compared to MBP during adulthood, and their target proteins revealed a complete normalization in aged ENU2 mice. In conclusion, these results provide a new perspective on the PKU pathophysiology understanding and on a possible treatment, emphasizing the potential modulating role of differentially expressed microRNAs in MBP expression on PKU brains during PKU mouse lifespan.

Pancreas divisum: correlation between anatomical abnormalities and bile precipitation in the gallbladder in seven patients

Pancreas divisum is a genetic defect associated with recurrent acute pancreatitis due to insufficient drainage of the accessory pancreatic duct. Seven young patients diagnosed with pancreatic divisum and thickening of the gallbladder bile as shown on magnetic resonance cholangio-pancreatography without pancreatic ductal changes underwent laparoscopic cholecystectomy. During the mean follow-up of 32 months no episode of pancreatitis was reported. There is an association between PD and higher concentration of bile in the gallbladder. Cholecystectomy can be considered curative in patients with PD in the absence of indications for major surgery.

Deep vein thrombosis of the lower limb secondary to lumbar discal hernia compression: a rarity? Review of the literature

This case report is about a 70-years-old female patient, suffering from discal hernia, with compression of the iliac vein, that led to the formation of deep vein thrombosis of the lower limbs. The angio-CT scan revealed the starting point of the L4- L5 compression where a voluminous discal hernia caused deep vein thrombosis, with the involvement the femoro-popliteal venous axis. Blood samples and PET-CT scans excluded other possible etiologic factors. This case demonstrates how a voluminous discal hernia can cause venous thrombosis.

The nucleoplasmic interactions among Lamin A/C-pRB-LAP2α-E2F1 are modulated by dexamethasone

Ataxia telangiectasia (AT) is a rare genetic neurodegenerative disease. To date, there is no available cure for the illness, but the use of glucocorticoids has been shown to alleviate the neurological symptoms associated with AT. While studying the effects of dexamethasone (dex) in AT fibroblasts, by chance we observed that the nucleoplasmic Lamin A/C was affected by the drug. In addition to the structural roles of A-type lamins, Lamin A/C has been shown to play a role in the regulation of gene expression and cell cycle progression, and alterations in the LMNA gene is cause of human diseases called laminopathies. Dex was found to improve the nucleoplasmic accumulation of soluble Lamin A/C and was capable of managing the large chromatin Lamin A/C scaffolds contained complex, thus regulating epigenetics in treated cells. In addition, dex modified the interactions of Lamin A/C with its direct partners lamin associated polypeptide (LAP) 2a, Retinoblastoma 1 (pRB) and E2F Transcription Factor 1 (E2F1), regulating local gene expression dependent on E2F1. These effects were differentially observed in both AT and wild type (WT) cells. To our knowledge, this is the first reported evidence of the role of dex in Lamin A/C dynamics in AT cells, and may represent a new area of research regarding the effects of glucocorticoids on AT. Moreover, future investigations could also be extended to healthy subjects or to other pathologies such as laminopathies since glucocorticoids may have other important effects in these contexts as well.

The influence of redox modulation on hypoxic endothelial cell metabolic and proteomic profiles through a small thiol-based compound tuning glutathione and thioredoxin systems

Reduction in oxygen levels is a key feature in the physiology of the bone marrow (BM) niche where hematopoiesis occurs. The BM niche is a highly vascularized tissue and endothelial cells (ECs) support and regulate blood cell formation from hematopoietic stem cells (HSCs). While in vivo studies are limited, ECs when cultured in vitro at low O2 (<5%), fail to support functional HSC maintenance due to oxidative environment. Therefore, changes in EC redox status induced by antioxidant molecules may lead to alterations in the cellular response to hypoxia likely favoring HSC self-renewal. To evaluate the impact of redox regulation, HUVEC, exposed for 1, 6, and 24 h to 3% O2 were treated with N-(N-acetyl-l-cysteinyl)-S-acetylcysteamine (I-152). Metabolomic analyses revealed that I-152 increased glutathione levels and influenced the metabolic profiles interconnected with the glutathione system and the redox couples NAD(P)+/NAD(P)H. mRNA analysis showed a lowered gene expression of HIF-1α and VEGF following I-152 treatment whereas TRX1 and 2 were stimulated. Accordingly, the proteomic study revealed the redox-dependent upregulation of thioredoxin and peroxiredoxins that, together with the glutathione system, are the main regulators of intracellular ROS. Indeed, a time-dependent ROS production under hypoxia and a quenching effect of the molecule were evidenced. At the secretome level, the molecule downregulated IL-6, MCP-1, and PDGF-bb. These results suggest that redox modulation by I-152 reduces oxidative stress and ROS level in hypoxic ECs and may be a strategy to fine-tune the environment of an in vitro BM niche able to support functional HSC maintenance.

New human ATM variants are able to regain ATM functions in ataxia telangiectasia disease

Ataxia telangiectasia is a rare neurodegenerative disease caused by biallelic mutations in the ataxia telangiectasia mutated gene. No cure is currently available for these patients but positive effects on neurologic features in AT patients have been achieved by dexamethasone administration through autologous erythrocytes (EryDex) in phase II and phase III clinical trials, leading us to explore the molecular mechanisms behind the drug action. During these investigations, new ATM variants, which originated from alternative splicing of ATM messenger, were discovered, and detected in vivo in the blood of AT patients treated with EryDex. Some of the new ATM variants, alongside an in silico designed one, were characterized and examined in AT fibroblast cell lines. ATM variants were capable of rescuing ATM activity in AT cells, particularly in the nuclear role of DNA DSBs recognition and repair, and in the cytoplasmic role of modulating autophagy, antioxidant capacity and mitochondria functionality, all of the features that are compromised in AT but essential for neuron survival. These outcomes are triggered by the kinase and further functional domains of the tested ATM variants, that are useful for restoring cellular functionality. The in silico designed ATM variant eliciting most of the functionality recover may be exploited in gene therapy or gene delivery for the treatment of AT patients.

Exploring machine learning for untargeted metabolomics using molecular fingerprints

BACKGROUND

Metabolomics, the study of substrates and products of cellular metabolism, offers valuable insights into an organism's state under specific conditions and has the potential to revolutionise preventive healthcare and pharmaceutical research. However, analysing large metabolomics datasets remains challenging, with available methods relying on limited and incompletely annotated metabolic pathways.

METHODS

This study, inspired by well-established methods in drug discovery, employs machine learning on metabolite fingerprints to explore the relationship of their structure with responses in experimental conditions beyond known pathways, shedding light on metabolic processes. It evaluates fingerprinting effectiveness in representing metabolites, addressing challenges like class imbalance, data sparsity, high dimensionality, duplicate structural encoding, and interpretable features. Feature importance analysis is then applied to reveal key chemical configurations affecting classification, identifying related metabolite groups.

RESULTS

The approach is tested on two datasets: one on Ataxia Telangiectasia and another on endothelial cells under low oxygen. Machine learning on molecular fingerprints predicts metabolite responses effectively, and feature importance analysis aligns with known metabolic pathways, unveiling new affected metabolite groups for further study.

CONCLUSION

In conclusion, the presented approach leverages the strengths of drug discovery to address critical issues in metabolomics research and aims to bridge the gap between these two disciplines. This work lays the foundation for future research in this direction, possibly exploring alternative structural encodings and machine learning models.

Redox modulation via a synthetic thiol compound reshapes energy metabolism in endothelial cells and ameliorates angiogenic expression in a co-culture study with activated macrophages

The vascular endothelium is the first interface exposed to circulating compounds and oxidative as well as pro-inflammatory stimuli. Nowadays, cysteine pro-drugs are emerging as new and potential therapies in cardiovascular and inflammatory diseases due to their cytoprotective effects. In this study, the effects of redox modulation by a synthetic thiol compound, i.e., I-152, a precursor of N-acetylcysteine (NAC) and cysteamine (MEA), were evaluated after 6 h and 24 h treatment on human umbilical cord endothelial cell (HUVECs) energy metabolism. Following I-152 treatment, higher cysteine and glutathione (GSH) content were detected via HPLC, in concomitance with I-152 derivatives, i.e., NAC and MEA. Untargeted metabolomics confirmed GSH upregulation and NAC presence in addition to I-152 itself and other metabolites, such as dithiol compound (NACMEAA) and triacetylated I-152. Mass spectrometry revealed that I-152 boosted ATP production, specifically through the mitochondrial OXPHOS, as determined via Seahorse assay without inducing oxidative stress. Additionally, I-152 treatment of HUVECs before co-culture with LPS-stimulated macrophages provided GSH and cysteine sustainment and attenuated the transcription of adhesion molecules as well as iNOS expression. Identifying the impact of redox regulation in physiological conditions and the possible metabolic targets could aid the application of novel thiol-based therapeutics.

Dexamethasone induces p21cip1/waf1 expression via FoxO3a independently of the Lamin A/C-HDAC2 interaction in Ataxia Telangiectasia

Ataxia-Telangiectasia (A-T) is a very rare autosomal recessive multisystemic disorder which to date is still uncurable. The use of glucocorticoid analogues, such as dexamethasone (dex), can improve neurological symptoms in patients, but the molecular mechanism of action of these analogues remains unclear. Here we report the effects of dex in regulating the interaction between Lamin A/C and HDAC2 in WT and A-T cells. Upon administration of dex to A-T cells, we first observed that the accumulation of HDAC2 on the CDKN1A promoter did not exert a repressive role on p21^cip1/waf1 expression, and second, we established that HDAC2 accumulation was not dependent on Lamin A/C. Both of these results are contrary to previous reported outcomes in other cellular models. Furthermore, large amounts of LAP2α and FoxO3a were found to occupy the CDKN1A promoter with matched p21^cip1/waf1 overexpression. Hence, in A-T cells p21 could be activated as a result of a dex-induced rearrangement of a multicomponent complex, composed of Lamin A/C, HDAC2, LAP2α, pRb, E2F1 and FoxO3a, at the CDKN1A gene promoter.