👤 Hammad Ismail

Psychosis in Alzheimer's disease (AD), including hallucinations and delusions, affects up to 50% of patients and is linked to faster cognitive decline. Delusions can occur across AD, with persecutory delusions early and misidentification delusions late, while hallucinations emerge in advanced stages and predict greater cognitive and functional decline. The APOE4 allele is the strongest genetic risk factor for late-onset AD, although its influence on neuropsychiatric symptoms, including psychosis, remains unclear. This study examined the interaction between APOE4 status, sex, EHT use, and psychosis symptoms in AD using data from participants in the National Alzheimer's Coordinating Center Uniform Data Set. Generalized Additive Models assessed nonlinear associations between predictors and psychosis outcomes, including the presence of delusions, hallucinations, and their visual and auditory subtypes. Analyses were stratified by sex (males: n = 13,841, females: n = 15,354). Predictor variables included APOE4 status, current use of estrogen hormone therapy (EHT) in females. Due to limited data availability, CSF biomarkers (Aβ1-42, p-tau181, t-tau) could not be included in the main models and were instead examined in a secondary sub analysis. APOE4 homozygosity was associated with significantly greater odds of delusions in the past month in both males and females, with a stronger effect in females (p<0.05). In females only, APOE4 homozygosity was significantly associated with hallucinations, with no effect in males (p<0.05). EHT was associated with lower risk of hallucinations in females (p<0.05). These findings underscore sex-specific genetic and biological contributors to psychosis in AD and support sex-stratified approaches to understanding and addressing psychosis symptoms in clinical settings. Show less

BackgroundFunctional independence is crucial for healthy aging, and its loss is a diagnostic criterion for dementia, including Alzheimer's disease. However, functional impairment (FI) can emerge before dementia diagnosis. Early and accurate characterization of FI may help identify individuals at elevated risk of cognitive decline and dementia.ObjectiveExploring the utility of capturing persistent versus impersistent FI, to identify a higher-risk group for incident cognitive decline and dementia.MethodData from 11,793 cognitively normal (CN) older adults from the National Alzheimer's Coordinating Center were analyzed. Exploratory factor analysis identified four Functional Activities Questionnaire items-preparing hot drinks, preparing balanced meals, shopping, and traveling-representing primarily functional abilities. An FI composite score was calculated as the sum of these items. Persistent FI was operationalized as FI present (composite score ≥ 2) at more than two-thirds of all visits prior to cognitive decline and dementia. Comparator groups were impersistent/transient FI and no FI. Time-dependent covariate Cox models compared incidence of cognitive decline and dementia across time-dependent FI groups, adjusted for demographics, Show less

Functional impairment (FI) is a key criterion for diagnosing dementia. However, subtle functional changes may occur during preclinical and prodromal phases but may not be accurately characterized. Furthermore, research linking FI to Alzheimer disease (AD) biofluid biomarkers is limited. Here we examined cross-sectional associations between cerebrospinal fluid (CSF) AD biomarkers and persistent versus transient FI in dementia-free older adults, and the longitudinal association of FI with incident dementia. Data from 1000 participants (age 72.9 ± 7.0; 45.2% female; 62.8% MCI) from the Alzheimer's Disease Neuroimaging Initiative were analyzed. CSF biomarkers included p-tau181, Aβ42, and ptau-181/Aβ42 ratio. Three Functional Activities Questionnaire items of "preparing a hot beverage," "preparing a balanced meal," and "shopping alone" were identified by factor analysis as assessing function rather than cognition directly. Persistent-FI was operationalized as FI present at> two-thirds of pre-dementia visits. Comparator groups included Transient-FI and No-FI. Linear regression modeled the association between FI status and baseline biomarker levels, while Cox regression assessed the association between FI and incident dementia. Models adjusted for age, sex, education, APOE-ε4 status, and MMSE. Compared to No-FI, Persistent-FI was associated with lower Aβ42 (Beta = -8.93; 95% CI: -13.56 to -4.03; p < 0.001), higher p-tau181 (Beta = 10.81; 95% CI: 0.44-22.26; p = 0.041), and ptau181/Aβ42 ratio (Beta = 21.66; 95% CI: 7.02-38.31; p = 0.003). In contrast, Transient-FI showed no significant associations. APOE-ε4 carrier status was more prevalent in the Persistent-FI group compared to No-FI (p = 0.009), but not in Transient-FI (p = 0.931). Compared to No-FI, Persistent-FI had a 6.66-fold greater dementia incidence rate (95% CI: 4.98-8.91, p < 0.001), while Transient-FI had a 1.72-fold greater incidence rate (95% CI: 1.09-2.72, p = 0.021). Findings extend the limited research on the association of FI with CSF AD biomarkers in dementia-free populations. Operationalizing FI-related risk by persistence enhances prognostication, identifying individuals with greater AD pathology and progression risk. This approach could enhance screening, early detection, and risk stratification, informing timely interventions before dementia onset. Show less

Autophagy, a critical homeostatic process, is increasingly implicated in cancer progression and therapy resistance. SAR405 is a potent inhibitor of the autophagy related PIK3C3/VPS34 complex, offering potential as an anticancer agent. This study reports the synthesis, characterization, and biological evaluation of SAR405-loaded chitosan nanoparticles (CNP-SAR405) designed to improve therapeutic delivery and efficacy in A549 human lung carcinoma cells. CNPs were prepared via ionic gelation using chitosan and sodium tripolyphosphate (TPP), yielding stable monodisperse nanoparticles ~ 77.4 nm, PDI ~ 0.2). Upon SAR405 encapsulation, nanoparticle size increased to ~ 110 nm while maintaining uniform distribution. Encapsulation efficiency reached 80% at 200 nM SAR405, confirmed by UV-Vis spectroscopy. Morphological analyses using FESEM and TEM verified spherical nanoparticle structures, while FTIR confirmed successful SAR405 incorporation. FITC-labelling enabled real-time tracking of intracellular uptake, revealing detectable internalization as early as 12 h post-treatment, with fluorescence intensity peaking at 72 h. In vitro cytotoxicity assays demonstrated enhanced anticancer efficacy of CNP-SAR405 compared to free SAR405, CNP-SAR405 achieved similar cytotoxic effects at 69 nM compared to 100 nM for free SAR405 in A549 cells. Furthermore, co-treatment with the autophagy inducer Torin-2 validated that CNP-SAR405 more effectively inhibited autophagosome formation than SAR405 alone, particularly at the 24-h mark. These findings underscore the potential of chitosan nanoparticle-mediated delivery to increase SAR405 bioavailability and anticancer potency while achieving comparable cytotoxic at a lower dose than free SAR405. The CNP-SAR405 formulation represents a promising nanotechnology-driven approach to targeted lung cancer therapy. All experiments were performed in triplicate biological replicates with technical triplicates, and data were analysed using one-way ANOVA followed by Tukey's multiple comparison post-hoc test (p < 0.05 considered significant). Show less

Compounds with a chalcone scaffold-based structure have demonstrated promising anticancer biological activity. However, the molecular interactions between chalcone scaffold-based compounds and breast cancer-associated proteins remain unclear. Through network pharmacology, molecular docking, and molecular dynamics (MD) simulation analyses, compounds with a chalcone scaffold-based structure were evaluated for their interaction with potential breast cancer targets. The compounds were retrieved from the ASINEX database, resulting in 575,302 compounds. A total of 342 compounds with chalcone scaffold-based structures were discovered. From the 342 compounds that was analysed, ten were chosen due to their adherence to Lipinski's rule, having an appropriate range of lipophilicity (LOGP), and topological polar surface area (TPSA), and absence of any toxicity. Based on target intersection, 50 target genes were found and subjected to protein-protein interaction (PPI), gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Four target genes were found to be involved in the breast cancer pathway. Consequently, molecular docking was utilised to analyse the molecular interactions between the compounds and four target protein receptors. Compound Show less

An optimization strategy was adopted for designing and synthesizing new series of 2-oxindole conjugates. Selected compounds were evaluated for their antiproliferative effect in vitro against NCI-60 cell lines panel, inhibitory effect on carbonic anhydrase (CA) isoforms (hCAI, II, IX and XII), and protein kinases. Compounds 5 and 7 showed promising inhibitory effects on hCA XII, whereas compound 4d was the most potent inhibitor with low nanomolar CA inhibition against all tested isoforms. These results were rationalized by using molecular docking. Despite its lack of CA inhibitory activity, compound 15c was the most active antiproliferative candidate against most of the 60 cell lines with mean growth inhibition 61.83% and with IC Show less

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder with unmet medical need. This investigation consisted of testing a range of ethanolic ethnomedicinal plant extracts (n = 18) traditionally used in the treatment of disorders such as anxiety, delirium, and memory loss. They were then screened for in vitro inhibitory activity against acetylcholinesterase (AChE), butylcholinesterase (BuChE), beta-secretase 1/beta-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1), and antioxidant activities. Plants with potent activities were further characterised using a recently developed in vivo model of AD, Globodera pallida. The ability of phytoextracts to protect this organism against amyloid-beta Aβ (1-42) exposure was assessed by measuring chemosensing, survival rate, production of reactive oxygen species (ROS), and antioxidant responses. Extracts (n = 5) from Juglans regia (leaves), Ellettaria cardamomum (seeds), Cinnamomum zeylanicum (bark), Salvia officinalis (leaves/flowers), and Hypericum perforatum (flowers) exerted concentration-dependent inhibitory activities against AChE and BuChE. Three of these plant extracts (i.e., J. regia, E. cardamomum, and S. officinalis) possessed strong concentration-dependent inhibitory activity against BACE1. Furthermore, the five selected medicinal plant extracts not only enhanced significantly (p < 0.05) the nematode’s chemosensing, survival rate, and antioxidant responses (i.e., anti-ROS production, mitochondrial reductase activity, oxidized glutathione (GSSG) to reduced glutathione (GSH) ratio), but also greatly restored (p < 0.05) in a concentration-dependent manner the Aβ (1-42)-induced deleterious changes in these same parameters. In brief, this investigation highlights plant extracts with strong anti-AD activities which could be trialled as novel therapeutic supplements or undergo further biodiscovery research. Show less

Effective treatments and animal models for the most prevalent neurodegenerative form of blindness in elderly people, called age-related macular degeneration (AMD), are lacking. Genome-wide association studies have identified lipid metabolism and inflammation as AMD-associated pathogenic pathways. Given liver X receptors (LXRs), encoded by the nuclear receptor subfamily 1 group H members 2 and 3 (NR1H3 and NR1H2), are master regulators of these pathways, herein we investigated the role of LXR in human and mouse eyes as a function of age and disease and tested the therapeutic potential of targeting LXR. We identified immunopositive LXR fragments in human extracellular early dry AMD lesions and a decrease in LXR expression within the retinal pigment epithelium (RPE) as a function of age. Aged mice lacking LXR presented with isoform-dependent ocular pathologies. Specifically, loss of the Nr1h3 isoform resulted in pathobiologies aligned with AMD, supported by compromised visual function, accumulation of native and oxidized lipids in the outer retina, and upregulation of ocular inflammatory cytokines, while absence of Nr1h2 was associated with ocular lipoidal degeneration. LXR activation not only ameliorated lipid accumulation and oxidant-induced injury in RPE cells but also decreased ocular inflammatory markers and lipid deposition in a mouse model, thereby providing translational support for pursuing LXR-active pharmaceuticals as potential therapies for dry AMD. Show less

There is a growing interest in standardizing gene-disease associations for the purpose of facilitating the proper classification of variants in the context of Mendelian diseases. One key line of evidence is the independent observation of pathogenic variants in unrelated individuals with similar phenotypes. Here, we expand on our previous effort to exploit the power of autozygosity to produce homozygous pathogenic variants that are otherwise very difficult to encounter in the homozygous state due to their rarity. The identification of such variants in genes with only tentative associations to Mendelian diseases can add to the existing evidence when observed in the context of compatible phenotypes. In this study, we report 20 homozygous variants in 18 genes ( Show less

G-protein coupled receptors represent the largest family of membrane receptors. G-protein dependent signal of GPCR is classically thought to originate exclusively from the plasma membrane and, until very recently, internalized GPCRs were considered silent. At present, experimental proofs exist showing that GPCR can continue to signal via G proteins after internalization. We demonstrated that, once internalized in early endosomes, Glucose-dependent Insulinotropic Peptide Receptor (GIPR) continues to stimulate production of cAMP and activate PKA. In addition to indirect proofs showing that kinetics of cAMP production and PKA activation depend on internalization and GIPR trafficking, we identified the active form of Gαs on early endosomes containing GIPR and detected a distinct FRET signal accounting for cAMP production at the surface of endosomes containing GIP, relative to endosomes without GIP. Show less

An early intervention using biomarkers to predict acute myocardial infarction (AMI) will effectively reduce global heart attack incidence, particularly among high-risk patients with type 2 diabetes mellitus (T2DM). This study attempted to identify potential biomarkers by detecting changes in the levels of plasma proteins in T2DM patients following onset of AMI in comparison with those without AMI. Volunteer T2DM patients without AMI (control; n=10) and T2DM patients with AMI (n=10) were recruited. Plasma samples from these patients were evaluated via two-dimensional gel electrophoresis (2DE) to screen for proteins with level changes between the two groups. The abundance of spots on gel images was analyzed using Progenesis SameSpots and subjected to false discovery rate (FDR) analysis. Protein spots with statistically significant changes of at least 1.5 fold were selected for mass spectrometry (MS) analysis. Due to strong cardiac connections, tetranectin and titin were evaluated by enzymelinked immunosorbent assay (ELISA). The adjusted P-values and fold changes between the two groups resulted in identification of 34 protein spots with significantly altered abundance. Upon MS analysis, 17 plasma proteins were identified: tetranectin, titin, clusterin, haptoglobin, myosin-13, zinc fnger protein 445, DNA repair protein RAD50, serum albumin, apolipoprotein A-IV, caspase-6, aminoacyl tRNA synthase complex-interacting multifunctional protein 1, serotransferrin, retinol-binding protein 4, transthyretin, alpha-1-antitrypsin, apolipoprotein A-I and serum amyloid A. Comparable patterns of changes in tetranectin and titin between the control and AMI groups were confirmed using ELISA. In summary, tetranectin and titin in plasma appeared to be closely associated with the onset of AMI among T2DM patients and can be used as potential biomarkers for prediction of a cardiac event, though this requires validation in a prospective cohort study. Show less

Patients with anorexia nervosa (AN) are ideally suited to identify differentially methylated genes in response to starvation. We examined high-throughput DNA methylation derived from whole blood of 47 females with AN, 47 lean females without AN and 100 population-based females to compare AN with both controls. To account for different cell type compositions, we applied two reference-free methods (FastLMM-EWASher, RefFreeEWAS) and searched for consensus CpG sites identified by both methods. We used a validation sample of five monozygotic AN-discordant twin pairs. Fifty-one consensus sites were identified in AN vs. lean and 81 in AN vs. population-based comparisons. These sites have not been reported in AN methylation analyses, but for the latter comparison 54/81 sites showed directionally consistent differential methylation effects in the AN-discordant twins. For a single nucleotide polymorphism rs923768 in CSGALNACT1 a nearby site was nominally associated with AN. At the gene level, we confirmed hypermethylated sites at TNXB. We found support for a locus at NR1H3 in the AN vs. lean control comparison, but the methylation direction was opposite to the one previously reported. We confirm genes like TNXB previously described to comprise differentially methylated sites, and highlight further sites that might be specifically involved in AN starvation processes. Show less

NALCN is a conserved cation channel, which conducts a permanent sodium leak current and regulates resting membrane potential and neuronal excitability. It is part of a large ion channel complex, the "NALCN channelosome", consisting of multiple proteins including UNC80 and UNC79. The predominant neuronal expression pattern and its function suggest an important role in neuronal function and disease. So far, biallelic NALCN and UNC80 variants have been described in a small number of individuals leading to infantile hypotonia, psychomotor retardation, and characteristic facies 1 (IHPRF1, OMIM 615419) and 2 (IHPRF2, OMIM 616801), respectively. Heterozygous de novo NALCN missense variants in the S5/S6 pore-forming segments lead to congenital contractures of the limbs and face, hypotonia, and developmental delay (CLIFAHDD, OMIM 616266) with some clinical overlap. In this study, we present detailed clinical information of 16 novel individuals with biallelic NALCN variants, 1 individual with a heterozygous de novo NALCN missense variant and an interesting clinical phenotype without contractures, and 12 individuals with biallelic UNC80 variants. We report for the first time a missense NALCN variant located in the predicted S6 pore-forming unit inherited in an autosomal-recessive manner leading to mild IHPRF1. We show evidence of clinical variability, especially among IHPRF1-affected individuals, and discuss differences between the IHPRF1- and IHPRF2 phenotypes. In summary, we provide a comprehensive overview of IHPRF1 and IHPRF2 phenotypes based on the largest cohort of individuals reported so far and provide additional insights into the clinical phenotypes of these neurodevelopmental diseases to help improve counseling of affected families. Show less

Until very recently, G-protein dependent signal of GPCRs was thought to originate exclusively from the plasma membrane and internalized GPCRs were considered silent. Here, we demonstrated that, once internalized and located in the membrane of early endosomes, glucose-dependent Insulinotropic receptor (GIPR) continues to trigger production of cAMP and PKA activation. Direct evidence is based on identification of the active form of Gαs in early endosomes containing GIPR using a genetically encoded GFP tagged nanobody, and on detection of a distinct FRET signal accounting for cAMP production at the surface of endosomes containing GIP, compared to endosomes without GIP. Furthermore, decrease of the sustained phase of cAMP production and PKA activation kinetics as well as reversibility of cAMP production and PKA activity following GIP washout in cells treated with a pharmacological inhibitor of GIPR internalization, and continuous increase of cAMP level over time in the presence of dominant-negative Rab7, which causes accumulation of early endosomes in cells, were noticed. Hence the GIPR joins the few GPCRs which signal through G-proteins both at plasma membrane and on endosomes. Show less

How incretins regulate presence of their receptors at the cell surface and their activity is of paramount importance for the development of therapeutic strategies targeting these receptors. We have studied internalization of the human Glucose-Insulinotropic Polypeptide receptor (GIPR). GIP stimulated rapid robust internalization of the GIPR, the major part being directed to lysosomes. GIPR internalization involved mainly clathrin-coated pits, AP-2 and dynamin. However, neither GIPR C-terminal region nor β-arrestin1/2 was required. Finally, N-acetyl-GIP recognized as a dipeptidyl-IV resistant analogue, fully stimulated cAMP production with a ∼15-fold lower potency than GIP and weakly stimulated GIPR internalization and desensitization of cAMP response. Furthermore, docking N-acetyl-GIP in the binding site of modeled GIPR showed slighter interactions with residues of helices 6 and 7 of GIPR compared to GIP. Therefore, incomplete or partial activity of N-acetyl-GIP on signaling involved in GIPR desensitization and internalization contributes to the enhanced incretin activity of this peptide. Show less

Innovative crystallographic techniques have resulted in an exponential growth in the number of solved G-protein coupled receptor (GPCR) structures and a better understanding of the mechanisms of class A receptor activation and G protein binding. The recent release of the type 1 receptor for the corticotropin-releasing factor and the glucagon receptor structures, two members of the secretin-like family, gives the opportunity to understand these mechanisms of activation in this family of GPCRs. Here, we addressed the comparison of the functional elements of class A and secretin-like GPCRs, using the glucose-dependent insulinotropic polypeptide receptor (GIPR) as a model receptor. Inactive and active models of GIPR permitted to select, by structural homology with class A GPCRs, several residues that may form key interactions presumably involved in receptor activation and Gs coupling, for pharmacological evaluation. Mutants on these amino acids were expressed in HEKT 293 cells and characterized in terms of GIP-induced cAMP production. We identified various functional domains spanning from the peptide-binding to the G protein pockets: including: a network linking the extracellular part of transmembrane (TM) 6 with TMs 2 and 7; a polar lock that resembles the ionic-lock in class A GPCRs; an interaction between TMs 3 and 7 that favors activation; and two clusters of polar/charged and of hydrophobic residues that interact with the C-terminus of the Gα. The results show that despite the low degree of sequence similarity between rhodopsin- and secretin-like GPCRs, the two families share conserved elements in their mechanisms of activation and G protein binding. Show less