The developmental roots of neurodegeneration

Computational and functional prioritization identifies genes that rescue behavior and reduce tau protein in fly and human cell models of Alzheimer disease

Genome-wide association studies (GWASs) in Alzheimer disease (AD) have uncovered over 70 loci significantly associated with AD risk, but identifying the true causal gene(s) at these loci requires systematic functional validation that is rarely performed due to limitations of time and cost. Here, we integrate transcriptome-wide association study (TWAS) with colocalization analysis, fine-mapping, and additional annotation of AD GWAS variants to identify 123 genes at known and suggestive AD risk loci. A comparison with human AD brain transcriptome data confirmed that many of these candidate genes are dysregulated in human AD and correlate with neuropathology. We then tested all available orthologs in two well-established Drosophila AD models that express either wild-type tau or secreted β-amyloid (β42). Experimental perturbation of the 60 available candidates pinpointed 46 that modulated neuronal dysfunction in one or both fly models. The effects of 18 of these genes were concordant with the TWAS prediction, such that the direction of misexpression predicted to increase AD risk in humans exacerbated behavioral impairments in the AD fly models. Reversing the aberrant down- or upregulation of 11 of these genes (MTCH2, ELL, TAP2, HDC, DMWD, MYCL, SLC4A9, ABCA7, CSTF1, PTK2B, and CD2AP) proved neuroprotective in vivo. We further studied MTCH2 and found that it regulates steady-state tau protein levels in the Drosophila brain and reduces tau accumulation in human neural progenitor cells. This systematic, integrative approach effectively prioritizes genes at GWAS loci and reveals promising AD-relevant candidates for further investigation as risk factors or targets for therapeutic intervention.

Exploring the neurodegenerative potential of per- and polyfluoroalkyl substances through an adverse outcome pathway network

While emerging evidence links per- and polyfluoroalkyl substances (PFAS) to neurotoxicity, their potential role in neurodegeneration remains poorly understood. Moreover, existing neurodegeneration-related adverse outcome pathways (AOPs) available on AOP-Wiki have not yet been integrated into a unified network. To address these gaps, this study aims to develop the first neurodegeneration-related AOP network and utilize it to explore the possible contributions of long-chain legacy PFAS to neurodegeneration, specifically concerning Alzheimer's and Parkinson's diseases. A total of 74 AOPs were screened from AOP-Wiki, of which 13 neurodegeneration-related AOPs met the eligibility criteria and were incorporated into a network. We analyzed the resulting AOP network using topological parameters such as in-degree, out-degree, eccentricity, and betweenness centrality. To elucidate the mechanistic contributions of PFAS exposure to neurodegenerative pathways, we integrated evidence linking PFAS exposure to key events (KEs) within the network. The results highlighted increased intracellular calcium as the network hub with the highest connectivity followed by critical KEs such as neurodegeneration, neuronal apoptosis, oxidative stress, N-methyl-d-aspartate receptor (NMDA-R) overactivation, and mitochondrial dysfunction. Consistent with toxicological evidence, the pathways highlighted by the AOP network indicate that PFAS may adversely affect neurotransmitter systems, particularly through NMDA-R overactivation, leading to excitotoxicity. This may result in calcium dyshomeostasis, mitochondrial dysfunction, inflammatory-oxidative cascades, neuroinflammation, and neuronal cell death. By providing a mechanistic basis for understanding the neurodegenerative potential of PFAS, this study offers a crucial framework for assessing the risks associated with these chemicals which may inform future regulatory measures and public health strategies. Further experimental validation is needed to confirm the mechanistic contributions of PFAS exposure in neurodegeneration, particularly in animal models or human populations.

Non-Categorical Analyses Identify Rotenone-Induced 'Parkinsonian' Rats Benefiting from Nano-Emulsified Punicic Acid (Nano-PSO) in a Phenotypically Diverse Population: Implications for Translational Neurodegenerative Therapies

The pursuit of nutraceuticals to improve the quality of life for patients with neurodegenerative conditions is a dynamic field within neuropharmacology. Unfortunately, many nutraceuticals that show promise in preclinical studies fail to demonstrate significant clinical benefits in human trials, leading to their exclusion as therapeutic options. This discrepancy may stem from the categorical interpretation of preclinical and clinical results. Basic researchers often assume that non-human experimental animals exhibit less phenotypic variability than humans. This belief overlooks interindividual phenotype variation, thereby leading to categorical conclusions being drawn from experiments. Consequently, when human clinical trials are conducted, the researchers expect similarly conclusive results. If these results are not achieved, the nutraceutical is deemed ineffective for clinical use, even if numerous individuals might benefit. In our study, we evaluated whether analyzing phenotype variability and similarity through non-categorical methods could help identify rotenone (ROT)-treated rats that might benefit from consuming nano-emulsified punicic acid (Nano-PSO), even if the prevention of "parkinsonism" or the restoration of neurometabolic function is inconsistent across individuals. Our findings supported this hypothesis. The benefits of Nano-PSO were not categorical; however, analyzing phenotype variance allowed us to identify ROT rats with varying degrees of benefit from Nano-PSO consumption. Hence, the translational potential of results from basic science studies testing nutraceuticals as pharmaceutical products against neurodegeneration may improve if researchers also interpret their results using non-categorical methods of data analysis for population screening, even if the overall therapeutic outcomes for the entire population show internal inconsistencies.

Robotic Actuation-Mediated Quantitative Mechanogenetics for Noninvasive and On-Demand Cancer Therapy

Cell mechanotransduction signals are important targets for physical therapy. However, current physiotherapy heavily relies on ultrasound, which is generated by high-power equipment or amplified by auxiliary drugs, potentially causing undesired side effects. To address current limitations, a robotic actuation-mediated therapy is developed that utilizes gentle mechanical loads to activate mechanosensitive ion channels. The resulting calcium influx precisely regulated the expression of recombinant tumor suppressor protein and death-associated protein kinase, leading to programmed apoptosis of cancer cell line through caspase-dependent pathway. In stark contrast to traditional gene therapy, the complete elimination of early- and middle-stage tumors (volume ≤ 100 mm3) and significant growth inhibition of late-stage tumor (500 mm3) are realized in tumor-bearing mice by transfecting mechanogenetic circuits and treating daily with quantitative robotic actuation in a form of 5 min treatment over the course of 14 days. Thus, this massage-derived therapy represents a quantitative strategy for cancer treatment.

Interaction of sex and onset site on the disease trajectory of amyotrophic lateral sclerosis

BACKGROUND

Studies showed the impact of sex and onset site (spinal or bulbar) on disease onset and survival in ALS. However, they mainly result from cross-sectional or survival analysis, and the interaction of sex and onset site on the different proxies of disease trajectory has not been fully investigated.

METHODS

We selected all patients with repeated observations in the PRO-ACT database. We divided them into four groups depending on their sex and onset site. We estimated a multivariate disease progression model, named ALS Course Map, to investigate the combined temporal changes of the four sub-scores of the revised ALS functional rating scale (ALSFRSr), the forced vital capacity (FVC), and the body mass index (BMI). We then compared the progression rate, the estimated age at onset, and the relative progression of the outcomes across each group.

RESULTS

We included 1438 patients from the PRO-ACT database. They were 51% men with spinal onset, 12% men with bulbar onset, 26% women with spinal onset, and 11% women with bulbar onset. We showed a significant influence of both sex and onset site on the ALSFRSr progression. The BMI decreased 8.9 months earlier (95% CI [3.9, 13.8]) in women than men, after correction for the onset site. Among patients with bulbar onset, FVC was impaired 2.6 months earlier (95% CI [0.6, 4.6]) in women.

CONCLUSION

Using a multivariable disease modelling approach, we showed that sex and onset site are important drivers of the progression of motor function, BMI, and FVC decline.

Early clues and molecular mechanism involved in neurodegenerative diseases induced in immature mice by combined exposure to polypropylene microplastics and DEHP

Studies have shown that exposure to either microplastics (MPs) or di-(2-ethylhexyl) phthalic acid (DEHP) alone can cause neurotoxicity in animals, but it remains uncertain whether and to what extent co-exposure to these two substances, which often occur together in reality, can also induce neurotoxicity. This study aimed to investigate the neurotoxicity and molecular mechanisms of combined exposure to DEHP and polypropylene microplastics (synthetic PP-MPs were used), the microplastics most commonly encountered by young children, in immature mice. The results showed that exposure to PP-MPs and/or DEHP did cause neurotoxic effects in immature mice, including induction of neurocognitive and memory deficits, damage to the CA3 region of the hippocampus, increased oxidative stress, and decreased AChE activity in the brain. The severity of the neurotoxicity increased with increasing concentrations of PP-MPs, combined exposure to PP-MPs and DEHP exhibited additive or synergistic effects. Transcriptomic analyses revealed that the PP-MPs and/or DEHP exposure altered the expression profiles of gene clusters involved in the stress response, and in protein processing in endoplasmic reticulum. Quantitative analyses further indicated that PP-MPs and/or DEHP exposure inhibited the activity of the heat shock response mediated by heat shock transcription factor 1, while chronically activated the unfolded protein response, consequently inducing neurotoxicity through neuronal apoptosis and neuroinflammation in the immature mice. As a pioneer study to highlight the neurotoxicity induced by combined exposure to PP-MPs and DEHP in immature mice, this research provides new insights into mitigating the health risks of PP-MPs and DEHP exposure in young children.

Sex and Brain: The Role of Sex Chromosomes and Hormones in Brain Development and Parkinson's Disease

Sex hormones and genes on the sex chromosomes are not only key factors in the regulation of sexual differentiation and reproduction but they are also deeply involved in brain homeostasis. Their action is crucial for the development of the brain, which presents different characteristics depending on the sex of individuals. The role of these players in the brain is fundamental in the maintenance of brain function during adulthood as well, thus being important also with respect to age-related neurodegenerative diseases. In this review, we explore the role of biological sex in the development of the brain and analyze its impact on the predisposition toward and the progression of neurodegenerative diseases. In particular, we focus on Parkinson's disease, a neurodegenerative disorder that has a higher incidence in the male population. We report how sex hormones and genes encoded by the sex chromosomes could protect from the disease or alternatively predispose toward its development. We finally underline the importance of considering sex when studying brain physiology and pathology in cellular and animal models in order to better understand disease etiology and develop novel tailored therapeutic strategies.

Deep multimodality-disentangled association analysis network for imaging genetics in neurodegenerative diseases

Imaging genetics is a crucial tool that is applied to explore potentially disease-related biomarkers, particularly for neurodegenerative diseases (NDs). With the development of imaging technology, the association analysis between multimodal imaging data and genetic data is gradually being concerned by a wide range of imaging genetics studies. However, multimodal data are fused first and then correlated with genetic data in traditional methods, which leads to an incomplete exploration of their common and complementary information. In addition, the inaccurate formulation in the complex relationships between imaging and genetic data and information loss caused by missing multimodal data are still open problems in imaging genetics studies. Therefore, in this study, a deep multimodality-disentangled association analysis network (DMAAN) is proposed to solve the aforementioned issues and detect the disease-related biomarkers of NDs simultaneously. First, the imaging data are nonlinearly projected into a latent space and imaging representations can be achieved. The imaging representations are further disentangled into common and specific parts by using a multimodal-disentangled module. Second, the genetic data are encoded to achieve genetic representations, and then, the achieved genetic representations are nonlinearly mapped to the common and specific imaging representations to build nonlinear associations between imaging and genetic data through an association analysis module. Moreover, modality mask vectors are synchronously synthesized to integrate the genetic and imaging data, which helps the following disease diagnosis. Finally, the proposed method achieves reasonable diagnosis performance via a disease diagnosis module and utilizes the label information to detect the disease-related modality-shared and modality-specific biomarkers. Furthermore, the genetic representation can be used to impute the missing multimodal data with our learning strategy. Two publicly available datasets with different NDs are used to demonstrate the effectiveness of the proposed DMAAN. The experimental results show that the proposed DMAAN can identify the disease-related biomarkers, which suggests the proposed DMAAN may provide new insights into the pathological mechanism and early diagnosis of NDs. The codes are publicly available at https://github.com/Meiyan88/DMAAN.

Small Fluorogenic Amino Acids for Peptide-Guided Background-Free Imaging

The multiple applications of super-resolution microscopy have prompted the need for minimally invasive labeling strategies for peptide-guided fluorescence imaging. Many fluorescent reporters display limitations (e.g., large and charged scaffolds, non-specific binding) as building blocks for the construction of fluorogenic peptides. Herein we have built a library of benzodiazole amino acids and systematically examined them as reporters for background-free fluorescence microscopy. We have identified amine-derivatized benzoselenadiazoles as scalable and photostable amino acids for the straightforward solid-phase synthesis of fluorescent peptides. Benzodiazole amino acids retain the binding capabilities of bioactive peptides and display excellent signal-to-background ratios. Furthermore, we have demonstrated their application in peptide-PAINT imaging of postsynaptic density protein-95 nanoclusters in the synaptosomes from mouse brain tissues.

Small Fluorogenic Amino Acids for Peptide-Guided Background-Free Imaging

The multiple applications of super-resolution microscopy have prompted the need for minimally invasive labeling strategies for peptide-guided fluorescence imaging. Many fluorescent reporters display limitations (e.g., large and charged scaffolds, non-specific binding) as building blocks for the construction of fluorogenic peptides. Herein we have built a library of benzodiazole amino acids and systematically examined them as reporters for background-free fluorescence microscopy. We have identified amine-derivatized benzoselenadiazoles as scalable and photostable amino acids for the straightforward solid-phase synthesis of fluorescent peptides. Benzodiazole amino acids retain the binding capabilities of bioactive peptides and display excellent signal-to-background ratios. Furthermore, we have demonstrated their application in peptide-PAINT imaging of postsynaptic density protein-95 nanoclusters in the synaptosomes from mouse brain tissues.

Treating early postnatal circuit defect delays Huntington's disease onset and pathology in mice

Recent evidence has shown that even mild mutations in the Huntingtin gene that are associated with late-onset Huntington's disease (HD) disrupt various aspects of human neurodevelopment. To determine whether these seemingly subtle early defects affect adult neural function, we investigated neural circuit physiology in newborn HD mice. During the first postnatal week, HD mice have less cortical layer 2/3 excitatory synaptic activity than wild-type mice, express fewer glutamatergic receptors, and show sensorimotor deficits. The circuit self-normalizes in the second postnatal week but the mice nonetheless develop HD. Pharmacologically enhancing glutamatergic transmission during the neonatal period, however, rescues these deficits and preserves sensorimotor function, cognition, and spine and synapse density as well as brain region volume in HD adult mice.

Huntingtin coordinates dendritic spine morphology and function through cofilin-mediated control of the actin cytoskeleton

Compelling evidence indicates that in Huntington's disease (HD), mutation of huntingtin (HTT) alters several aspects of early brain development such as synaptogenesis. It is not clear to what extent the partial loss of wild-type HTT function contributes to these abnormalities. Here we investigate the function of HTT in the formation of spines. Although larger spines normally correlate with more synaptic activity, cell-autonomous depletion of HTT leads to enlarged spines but reduced excitatory synaptic function. We find that HTT is required for the proper turnover of endogenous actin and to recruit AMPA receptors at active synapses; loss of HTT leads to LIM kinase (LIMK) hyperactivation, which maintains cofilin in its inactive state. HTT therefore influences actin dynamics through the LIMK-cofilin pathway. Loss of HTT uncouples spine structure from synaptic function, which may contribute to the ultimate development of HD symptoms.

Repetitive afterglow in zirconia by pulsed near-infrared irradiation toward biological temperature sensing

Photoluminescence provides information about the surrounding environment. In this study, aiming to develop a non-invasive deep body-temperature sensing method, we investigated photoluminescence properties of afterglow zirconia (ZrO2) by pulsed near-infrared (NIR) light irradiation based on the biological temperature. Pulsed light irradiation produced optically stimulated luminescence, followed by afterglow, with the property of repeating 100 times or more. Furthermore, the basic principle of temperature measurement was demonstrated through afterglow decay curve measurements. The use of harmless ZrO2 as a sensing probe and NIR light, which is relatively permeable to living tissues, is expected to realize temperature measurements in the brain and may also facilitate optogenetic treatment.