Confined growth of Ag nanogap shells emitting stable Raman label signals for SERS liquid biopsy of pancreatic cancer.

To develop a reliable surface-enhanced Raman scattering (SERS) immunoassay as a new liquid biopsy modality, SERS nanoprobes emitting strong and stable signals are necessary. However, Ag nanoparticles used as SERS nanoprobes are prone to rapid fading of SERS signals by oxidation. This has driven the development of a new strategy for Ag-based SERS nanoprobes emitting stable and strong SERS signals over time. Herein, Ag nanogap shells entrapping Raman labels are created in the confined pores of mesoporous silica nanoparticles (AgNSM) through a rapid single-step reaction for SERS liquid biopsy. Each AgNSM nanoprobe possesses multiple nanogaps of 1.58 nm to entrap Raman labels, allowing superior long-term SERS signal stability and large enhancement of 1.5 × 106. AgNSM nanoprobes conjugated with an antibody specific for carbohydrate antigen (CA)19-9 are employed in the SERS sandwich immunoassay including antibody-conjugated magnetic nanoparticles for CA19-9 detection, showing a two orders of magnitude lower limit of detection (0.025 U mL-1) than an enzyme-linked immunosorbent assay (0.3 U mL-1). The AgNSM nanoprobe immunoassay accurately quantifies CA19-9 levels from clinical serum samples of early and advanced pancreatic cancer. AgNSM nanoprobes with stable SERS signals provide a new route to SERS liquid biopsy for effective detection of blood biomarkers.

Efficient generation of brain organoids using magnetized gold nanoparticles.

Brain organoids, which are three-dimensional cell culture models, have the ability to mimic certain structural and functional aspects of the human brain. However, creating these organoids can be a complicated and difficult process due to various technological hurdles. This study presents a method for effectively generating cerebral organoids from human induced pluripotent stem cells (hiPSCs) using electromagnetic gold nanoparticles (AuNPs). By exposing mature cerebral organoids to magnetized AuNPs, we were able to cultivate them in less than 3 weeks. The initial differentiation and neural induction of the neurosphere occurred within the first week, followed by maturation, including regional patterning and the formation of complex networks, during the subsequent 2 weeks under the influence of magnetized AuNPs. Furthermore, we observed a significant enhancement in neurogenic maturation in the brain organoids, as evidenced by increased histone acetylation in the presence of electromagnetic AuNPs. Consequently, electromagnetic AuNPs offer a promising in vitro system for efficiently generating more advanced human brain organoids that closely resemble the complexity of the human brain.

Single-cell RNA-sequencing identifies disease-associated oligodendrocytes in male APP NL-G-F and 5XFAD mice.

Alzheimer's disease (AD) is associated with progressive neuronal degeneration as amyloid-beta (Aß) and tau proteins accumulate in the brain. Glial cells were recently reported to play an important role in the development of AD. However, little is known about the role of oligodendrocytes in AD pathogenesis. Here, we describe a disease-associated subpopulation of oligodendrocytes that is present during progression of AD-like pathology in the male AppNL-G-F and male 5xFAD AD mouse brains and in postmortem AD human brains using single-cell RNA sequencing analysis. Aberrant Erk1/2 signaling was found to be associated with the activation of disease-associated oligodendrocytes (DAOs) in male AppNL-G-F mouse brains. Notably, inhibition of Erk1/2 signaling in DAOs rescued impaired axonal myelination and ameliorated Aß-associated pathologies and cognitive decline in the male AppNL-G-F AD mouse model.

APOE ε4-dependent effects on the early amyloid pathology in induced neurons of patients with Alzheimer's disease.

BACKGROUND: The ε4 allele of apolipoprotein E (APOE ε4) is the strongest known genetic risk factor for late-onset Alzheimer's disease (AD), associated with amyloid pathogenesis. However, it is not clear how APOE ε4 accelerates amyloid-beta (Aß) deposition during the seeding stage of amyloid development in AD patient neurons. METHODS: AD patient induced neurons (iNs) with an APOE ε4 inducible system were prepared from skin fibroblasts of AD patients. Transcriptome analysis was performed using RNA isolated from the AD patient iNs expressing APOE ε4 at amyloid-seeding and amyloid-aggregation stages. Knockdown of IGFBP3 was applied in the iNs to investigate the role of IGFBP3 in the APOE ε4-mediated amyloidosis. RESULTS: We optimized amyloid seeding stage in the iNs of AD patients that transiently expressed APOE ε4. Remarkably, we demonstrated that Aß  pathology was aggravated by the induction of APOE ε4 gene expression at the amyloid early-seeding stage in the iNs of AD patients. Moreover, transcriptome analysis in the early-seeding stage revealed that IGFBP3 was functionally important in the molecular pathology of APOE ε4-associated AD. CONCLUSIONS: Our findings suggest that the presence of APOE ε4 at the early Aß-seeding stage in patient iNs is critical for aggravation of sporadic AD pathology. These results provide insights into the importance of APOE ε4 expression for the progression and pathogenesis of sporadic AD.

Dormant state of quiescent neural stem cells links Shank3 mutation to autism development.

Autism spectrum disorders (ASDs) are common neurodevelopmental disorders characterized by deficits in social interactions and communication, restricted interests, and repetitive behaviors. Despite extensive study, the molecular targets that control ASD development remain largely unclear. Here, we report that the dormancy of quiescent neural stem cells (qNSCs) is a therapeutic target for controlling the development of ASD phenotypes driven by Shank3 deficiency. Using single-cell RNA sequencing (scRNA-seq) and transposase accessible chromatin profiling (ATAC-seq), we find that abnormal epigenetic features including H3K4me3 accumulation due to up-regulation of Kmt2a levels lead to increased dormancy of qNSCs in the absence of Shank3. This result in decreased active neurogenesis in the Shank3 deficient mouse brain. Remarkably, pharmacological and molecular inhibition of qNSC dormancy restored adult neurogenesis and ameliorated the social deficits observed in Shank3-deficient mice. Moreover, we confirmed restored human qNSC activity rescues abnormal neurogenesis and autism-like phenotypes in SHANK3-targeted human NSCs. Taken together, our results offer a novel strategy to control qNSC activity as a potential therapeutic target for the development of autism.

Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI promotes neuronal rejuvenation in aged mice.

An increasing number of studies have indicated that alterations in gut microbiota affect brain function, including cognition and memory ability, via the gut-brain axis. In this study, we aimed to determine the protective effect of Bifidobacterium bifidum BGN4 (B. bifidum BGN4) and Bifidobacterium longum BORI (B. longum BORI) on age-related brain damage in mice. We found that administration of B. bifidum BGN4 and B. longum BORI effectively elevates brain-derived neurotrophic factor expression which was mediated by increased histone 3 lysine 9 trimethylation. Furthermore, administration of probiotic supplementation reversed the DNA damage and apoptotic response in aged mice and also improved the age-related cognitive and memory deficits of these mice. Taken together, the present study highlights the anti-aging effects of B. bifidum BGN4 and B. longum BORI in the aged brain and their beneficial effects for age-related brain disorders.

Administration of Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI Improves Cognitive and Memory Function in the Mouse Model of Alzheimer's Disease.

Recent evidence indicates that gut microbiota could interact with the central nervous system and affect brain function, including cognition and memory. In this study, we investigated whether Bifidobacterium bifidum BGN4 (B. bifidum BGN4) and Bifidobacterium longum BORI (B. longum BORI) alleviated the pathological features in a mouse model of Alzheimer's disease (AD). Administration of B. bifidum BGN4 and B. longum BORI effectively suppressed amyloidosis and apoptotic processes and improved synaptic plasticity by ameliorating the neuroinflammatory response and BDNF expression. Moreover, behavioral tests indicated that B. bifidum BGN4 and B. longum BORI attenuated the cognitive and memory disability of AD mice. Taken together, the present study highlights the therapeutic potential of B. bifidum BGN4 and B. longum BORI for suppressing the pathological features of AD.

Nac1 facilitates pluripotency gene activation for establishing somatic cell reprogramming.

Transcription factors play a central role in pluripotency transcription circuitry for establishing pluripotent reprogramming. Master transcription factors Oct4, Nanog, and Sox2 are known to form the core of the pluripotency transcription network. Other transcription factors also play critical roles for further refining the core circuitry for pluripotency in induced pluripotent stem (iPS) cells. Here, we reported that Nac1 interacted with the master pluripotent factors Oct4 and Nanog co-occupies gene promoters bound by these transcriptional factors for establishing pluripotency. Moreover, this interaction coordinates gene expression with H3K4me3 in the somatic cell reprogramming. Knockdown of Nac1 suppressed somatic cell reprogramming, whereas overexpression of Nac1 resulted in enhanced efficiency of induced pluripotent cell generation. Altogether, these results reveal the genome wide role for Nac1 in the contribution to the pluripotency circuitry and the regulation of the establishing pluripotent state.

In vivo neuronal gene editing via CRISPR-Cas9 amphiphilic nanocomplexes alleviates deficits in mouse models of Alzheimer's disease.

In vivo gene editing in post-mitotic neurons of the adult brain may be a useful strategy for treating neurological diseases. Here, we develop CRISPR-Cas9 nanocomplexes and show they were effective in the adult mouse brain, with minimal off-target effects. Using this system to target Bace1 suppressed amyloid beta (Aß)-associated pathologies and cognitive deficits in two mouse models of Alzheimer's disease. These results broaden the potential application of CRISPR-Cas9 systems to neurodegenerative diseases.

Modeling G2019S-LRRK2 Sporadic Parkinson's Disease in 3D Midbrain Organoids.

Recent advances in generating three-dimensional (3D) organoid systems from stem cells offer new possibilities for disease modeling and drug screening because organoids can recapitulate aspects of in vivo architecture and physiology. In this study, we generate isogenic 3D midbrain organoids with or without a Parkinson's disease-associated LRRK2 G2019S mutation to study the pathogenic mechanisms associated with LRRK2 mutation. We demonstrate that these organoids can recapitulate the 3D pathological hallmarks observed in patients with LRRK2-associated sporadic Parkinson's disease. Importantly, analysis of the protein-protein interaction network in mutant organoids revealed that TXNIP, a thiol-oxidoreductase, is functionally important in the development of LRRK2-associated Parkinson's disease in a 3D environment. These results provide proof of principle for the utility of 3D organoid-based modeling of sporadic Parkinson's disease in advancing therapeutic discovery.

Salusin-ß mediate neuroprotective effects for Parkinson's disease.

Neuropeptides, small peptides found in many mammalian brain, play key roles in communicating with each other to modulate neuronal activity. Here, we reported that endogenous neuropeptide salusin-ß has neuroprotective effects on the midbrain dopamine neurons and can be used as an effective therapeutic treatment for Parkinson's disease (PD). We found that the MrgprA1 receptor mediates the neuroprotective effects of salusin-ß on the midbrain dopamine neurons. Importantly, intranasal administration of salusin-ß in a PD mouse model show the neuroprotection of dopaminergic neurons and increased the survival of midbrain dopamine neurons. Furthermore, inhibition of the salusin-ß receptor, MrgprA1, abolished the neuroprotective effects induced by salusin-ß. Taken together, these results demonstrate the novel role of salusin-ß in the central nervous system and salusin-ß can be used as a novel therapeutic to effectively treat PD.

Modelling APOE ɛ3/4 allele-associated sporadic Alzheimer's disease in an induced neuron.

The recent generation of induced neurons by direct lineage conversion holds promise for in vitro modelling of sporadic Alzheimer's disease. Here, we report the generation of induced neuron-based model of sporadic Alzheimer's disease in mice and humans, and used this system to explore the pathogenic mechanisms resulting from the sporadic Alzheimer's disease risk factor apolipoprotein E (APOE) ɛ3/4 allele. We show that mouse and human induced neurons overexpressing mutant amyloid precursor protein in the background of APOE ɛ3/4 allele exhibit altered amyloid precursor protein (APP) processing, abnormally increased production of amyloid-ß42 and hyperphosphorylation of tau. Importantly, we demonstrate that APOE ɛ3/4 patient induced neuron culture models can faithfully recapitulate molecular signatures seen in APOE ɛ3/4-associated sporadic Alzheimer's disease patients. Moreover, analysis of the gene network derived from APOE ɛ3/4 patient induced neurons reveals a strong interaction between APOE ɛ3/4 and another Alzheimer's disease risk factor, desmoglein 2 (DSG2). Knockdown of DSG2 in APOE ɛ3/4 induced neurons effectively rescued defective APP processing, demonstrating the functional importance of this interaction. These data provide a direct connection between APOE ɛ3/4 and another Alzheimer's disease susceptibility gene and demonstrate in proof of principle the utility of induced neuron-based modelling of Alzheimer's disease for therapeutic discovery.

Electromagnetized gold nanoparticles mediate direct lineage reprogramming into induced dopamine neurons in vivo for Parkinson's disease therapy.

Electromagnetic fields (EMF) are physical energy fields generated by electrically charged objects, and specific ranges of EMF can influence numerous biological processes, which include the control of cell fate and plasticity. In this study, we show that electromagnetized gold nanoparticles (AuNPs) in the presence of specific EMF conditions facilitate an efficient direct lineage reprogramming to induced dopamine neurons in vitro and in vivo. Remarkably, electromagnetic stimulation leads to a specific activation of the histone acetyltransferase Brd2, which results in histone H3K27 acetylation and a robust activation of neuron-specific genes. In vivo dopaminergic neuron reprogramming by EMF stimulation of AuNPs efficiently and non-invasively alleviated symptoms in mouse Parkinson's disease models. This study provides a proof of principle for EMF-based in vivo lineage conversion as a potentially viable and safe therapeutic strategy for the treatment of neurodegenerative disorders.

Generation of Integration-Free Induced Neurons Using Graphene Oxide-Polyethylenimine.

Direct conversion of somatic cells into induced neurons (iNs) without inducing pluripotency has great therapeutic potential for treating central nervous system diseases. Reprogramming of somatic cells to iNs requires the introduction of several factors that drive cell-fate conversion, and viruses are commonly used to deliver these factors into somatic cells. However, novel gene-delivery systems that do not integrate transgenes into the genome are required to generate iNs for safe human clinical applications. In this study, it is investigated whether graphene oxide-polyethylenimine (GO-PEI) complexes are an efficient and safe system for messenger RNA delivery for direct reprogramming of iNs. The GO-PEI complexes show low cytotoxicity, high delivery efficiency, and directly converted fibroblasts into iNs without integrating factors into the genome. Moreover, in vivo transduction of reprogramming factors into the brain with GO-PEI complexes facilitates the production of iNs that alleviated Parkinson's disease symptoms in a mouse model. Thus, the GO-PEI delivery system may be used to safely obtain iNs and could be used to develop direct cell reprogramming-based therapies for neurodegenerative diseases.

Efficient Direct Lineage Reprogramming of Fibroblasts into Induced Cardiomyocytes Using Nanotopographical Cues.

Induced cardiomyocytes (iCMs) generated via direct lineage reprogramming offer a novel therapeutic target for the study and treatment of cardiac diseases. However, the efficiency of iCM generation is significantly low for therapeutic applications. Here, we show an efficient direct conversion of somatic fibroblasts into iCMs using nanotopographic cues. Compared with flat substrates, the direct conversion of fibroblasts into iCMs on nanopatterned substrates resulted in a dramatic increase in the reprogramming efficiency and maturation of iCM phenotypes. Additionally, enhanced reprogramming by substrate nanotopography was due to changes in the activation of focal adhesion kinase and specific histone modifications. Taken together, these results suggest that nanotopographic cues can serve as an efficient stimulant for direct lineage reprogramming into iCMs.

Novel Neuroprotective Effects of Melanin-Concentrating Hormone in Parkinson's Disease.

Acupuncture has shown the therapeutic effect on various neurodegenerative disorders including Parkinson's disease (PD). While investigating the neuroprotective mechanism of acupuncture, we firstly found the novel function of melanin-concentrating hormone (MCH) as a potent neuroprotective candidate. Here, we explored whether hypothalamic MCH mediates the neuroprotective action of acupuncture. In addition, we aimed at evaluating the neuroprotective effects of MCH and elucidating underlying mechanism in vitro and in vivo PD models. First, we tested whether hypothalamic MCH mediates the neuroprotective effects of acupuncture by challenging MCH-R1 antagonist (i.p.) in mice PD model. We also investigated whether MCH has a beneficial role in dopaminergic neuronal protection in vitro primary midbrain and human neuronal cultures and in vivo MPTP-induced, Pitx3-/-, and A53T mutant mice PD models. Transcriptomics followed by quantitative PCR and western blot analyses were performed to reveal the neuroprotective mechanism of MCH. We first found that hypothalamic MCH biosynthesis was directly activated by acupuncture treatment and that administration of an MCH-R1 antagonist reverses the neuroprotective effects of acupuncture. A novel finding is that MCH showed a beneficial role in dopaminergic neuron protection via downstream pathways related to neuronal survival. This is the first study to suggest the novel neuroprotective action of MCH as well as the involvement of hypothalamic MCH in the acupuncture effects in PD, which holds great promise for the application of MCH in the therapy of neurodegenerative diseases.

Homogeneous generation of iDA neurons with high similarity to bona fide DA neurons using a drug inducible system.

Recent work generating induced dopaminergic (iDA) neurons using direct lineage reprogramming potentially provides a novel platform for the study and treatment Parkinson's disease (PD). However, one of the most important issues for iDA-based applications is the degree to which iDA neurons resemble the molecular and functional properties of their endogenous DA neuron counterparts. Here we report that the homogeneity of the reprogramming gene expression system is critical for the generation of iDA neuron cultures that are highly similar to endogenous DA neurons. We employed an inducible system that carries iDA-inducing factors as defined transgenes for direct lineage reprogramming to iDA neurons. This system circumvents the need for viral transduction, enabling a more efficient and reproducible reprogramming process for the generation of genetically homogenous iDA neurons. We showed that this inducible system generates iDA neurons with high similarity to their bona fide in vivo counterparts in comparison to direct infection methods. Thus, our results suggest that homogenous expression of exogenous genes in direct lineage reprogramming is critical for the generation of high quality iDA neuron cultures, making such culture systems a valuable resource for iDA-based drug screening and, ultimately, potential therapeutic intervention in PD.

Impaired motor coordination in Pitx3 overexpression mice.

Midbrain dopaminergic (DA) neurons are involved in the regulation of voluntary movement and in emotion-related behaviors and are affected in Parkinson's disease (PD). The homeodomain transcription factor Pitx3, which is uniquely expressed in midbrain DA neurons, plays a critical role in the development, function and maintenance of midbrain DA neurons. Pitx3 deficiency results in selective deficits of midbrain DA neurons in the substantia nigra pars compacta (SNc), reminiscent of the specific DA neuronal loss observed in PD. In this study, we found that selective overexpression of Pitx3 in intact midbrain DA neurons significantly affects the function of midbrain DA neurons. We observed changes in DA levels and gene expressions in mice overexpressing Pitx3. Furthermore, motor coordination and locomotion activities are significantly affected in mice overexpressing Pitx3, suggesting that the expression level of Pitx3 plays an important role in the function of midbrain DA neuron in vivo.