Abstract The systemic administration of therapeutic agents, particularly large, charged molecules such as antibodies, has limited efficacy in treating central nervous system (CNS) disorders. In addition, the slow progression of neurodegenerative diseases makes repeated intrathecal injections unfeasible. Alzheimer’s disease is characterized by the accumulation of Aβ amyloid plaques. Microglia contribute to the clearance of Aβ, but are inhibited by the expression of CD33. Therefore, antibody blocking of CD33 may enhance the phagocytosis of Aβ by microglial cells, slowing AD progression. Here, we use cells as “targeted cellular micropharmacies” that are retained in the CNS to deliver therapeutic proteins directly into the brain. To achieve this, we genetically engineered CD4 T-cells to express: (1) a chimeric antigen receptor against GD2 to retain the cells in the brain, (2) ectopic FoxP3 to reduce inflammation, (3) secreted IL-2 to promote cell longevity, and (4) secreted anti-CD33 scFv antibody. Our proof-of-concept demonstrates that therapeutic antibodies can be delivered to the brain for at least 8 weeks to treat neurological disorders. Other agents could be similarly delivered into the brain by this platform.

Ferroptosis, a metabolic cell death process driven by iron-dependent phospholipid peroxidation, is implicated in various pathologies, including cancer. While metabolic factors such as glucose, lipids, and multiple amino acids have all been demonstrated to modulate ferroptosis, the role of oxygen, another fundamental metabolic component, in ferroptosis is not fully understood. Here, we show that cells acclimated to a low oxygen environment develop marked resistance to ferroptosis, and this resistance is independent of canonical oxygen-sensing pathway mediated by prolyl hydroxylases (PHDs) and HIF transcription factors. Instead, hypoxia suppresses ferroptosis by inhibiting KDM6A, a tumor suppressor and oxygen-dependent histone demethylase, leading to reduced expression of its transcriptional targets, including lipid metabolic enzymes ACSL4 and ETNK1, thus rewiring cellular phospholipid profile to a ferroptosis-resistant state. Relevant to cancer, pharmacological inhibition of the oncogenic histone methyltransferase EZH2, which opposes KDM6A activity, restored ferroptosis sensitivity of xenograft bladder tumor tissues harboring KDM6A mutation.

This study presents the design and implementation of a surface plasmon resonance (SPR) sensor in the Kretschmann configuration, employing a gold film deposited on a flexible polydimethylsiloxane (PDMS) substrate as the SPR chip. The refractive-index sensitivity of the SPR sensor was evaluated with sodium chloride solutions of varying concentrations. Optimizing for both sensitivity and detection accuracy, the incident angle was fixed at 13°. The sensor exhibited a sensitivity of 3385.5 nm/RIU. Remarkably, the sensitivity variation was merely 1% after subjecting the sensor chip to 50 bending cycles in both forward and reverse directions. The sensor’s efficacy was further validated through the detection of alcohol content in three different Chinese Baijiu samples, yielding a maximum relative error of 4.04% and a minimum error of 0.17%. Additionally, the sensor was utilized to study the adsorption behavior of glutathione (GSH) on the gold film under varying pH conditions. The findings revealed optimal immediate adsorption at pH = 12, attributed to the complete deprotonation of mercapto groups, facilitating the formation of Au-S bonds with gold atoms. The best film-forming effect was observed at pH = 7, where the interplay of attractive and repulsive forces among different molecular groups led to the gradual extension of the molecular chain, resulting in a thicker molecular film.

The hippocampal dentate gyrus (DG) integrates multiple sensory inputs and encodes spatial memory. DG-dependent spatial memory deficits have been observed in early Alzheimer's disease (AD). Our previous study demonstrated that glutamate (Glu)-mediated excitotoxicity contributes to spatial learning and memory impairment in AD. It has been reported that the N-methyl-D-aspartic acid receptor (NMDAR) 2B subunit (NR2B) is predominantly localized to extrasynaptic sites, where it is associated with Ca²⁺ neurotoxicity and neuronal loss. However, the specific contribution of NR2B-mediated excitotoxicity to DG neuronal apoptosis and memory impairment in sporadic AD (sAD) remains unclear. In this study, we established a sAD rat model through a single intraventricular injection of streptozotocin combined with intraperitoneal injection of D-galactose. We investigated the role of NR2B in DG apoptosis and spatial learning and memory by microinjecting ifenprodil, an NR2B antagonist, into the hippocampal DG. Behavioral tests showed increased escape latency, reduced swimming distance in the target quadrant and platform crossings, and the significantly increased expression of cleaved caspase-3, PARP, and p-PERK, p-eIF2α, and CHOP in the sAD rats. Microinjection of ifenprodil into the DG markedly inhibited the levels of p-PERK, p-eIF2α, CHOP, cleaved caspase-3, PARP, and neuronal apoptosis in the DG, while also ameliorating the spatial learning and memory impairments in sAD rats. These results suggest that NR2B in the hippocampal DG is associated with neuronal apoptosis via the PERK-CHOP pathway and contributes to the spatial learning and memory deficits observed in sAD rats.

Tau aggregation plays a crucial role in the development of Alzheimer's disease (AD). Developing specific techniques that can isolate pathogenic tau from brain tissue is important for understanding tauopathies and advancing targeted therapies. Here, we develop photoaffinity small molecular probes and a novel method for in situ tissue labeling and investigate their activity in interacting with tau in cells and AD patient brains. Based on the reported chemical structures of tau PET tracers, we designed and synthesized two tau-specific probes, namely, Tau-2 and Tau-4. After validation in cell, mouse model, and patient brain samples, our photolabeling results suggested that Tau-2 effectively labels soluble tau in cell and mouse models, while Tau-4 selectively binds high-molecular-weight tau aggregates in late-stage AD patient brain tissues. Proteomic analysis verified the specific isolation of pathogenic tau from AD brain samples. Collectively, these findings underscore the potential of our photoaffinity probes as powerful tools for investigating tau proteins and neurofibrillary tangles in neurodegenerative diseases.

Neural stem cells (NSCs) showed a promising approach to treat Alzheimer's disease (AD). This study aims to investigate whether mouse NSCs transplantation can improve the function of learning and memory of AD mouse model and the underlying mechanism. NSCs was stereotaxically injected into the hippocampi of ibotenic acid (IBO)-induced AD mice. Behavioral tests were conducted to evaluate neurological function. Golgi and immunofluorescence staining were used to assess the injury of the nerves. Additionally, enhanced green fluorescent protein (EGFP) labeling was employed to evaluate the differentiation of NSCs. Compared with model group, NSCs transplantation shortened the escape latency and increased the crossing platform quadrant time, number of crossing the platform (p < 0.01). The preference index and active avoidance rate was increased after NSCs transplantation when compared with the model group (p < 0.05 or p < 0.01). NSCs augmented not only the number of neurons in the hippocampal CA1 region, but also the dendritic spine density, dendritic complexity and ACh content in the hippocampus (p < 0.05 or p < 0.01). Furthermore, NSCs also elevated the levels of BDNF in the hippocampus of AD mice (p < 0.01). It also showed that a portion of transplanted NSCs differentiated into neurons at four weeks post-transplantation. These results demonstrated that NSCs improved learning and memory function in the AD model by ameliorating neuron injury and differentiating into neurons.

>Endothelial cells (ECs) form a single cell layer that lines the inner surface of all blood and lymphatic vessels, acting as the barrier between vessels and underlying tissues. ECs are not only responsible for the flow of substances and fluid into and out of tissues but are also involved in many processes, such as coagulation, fibrinolysis,and regulation of vascular tone and inflammation. Therefore,dysfunction of ECs can result in serious issues throughout the body, such as atherosclerosis and coronary artery disease(Gimbrone and Garcia-Cardena, 2016).

To functionalize interfaces with supported biomembranes and membrane proteins, the challenge is to build stabilized and supported systems that mimic the native lipid microenvironment. Our objective is to control substrate-to-biomembrane spacing and the tethering chemistry so proteoliposomes can be fused and conjugated without perturbation of membrane protein function. Furthermore, the substrates need to exhibit low protein and antibody nonspecific binding to use these systems in assays. We have employed protein orthogonal coupling schemes in concert with multiarm poly(ethylene glycol) (PEG) technology to build supported biomembranes on microspheres. The lipid bilayer structures and tailored substrates of the microsphere-supported biomembranes were analyzed via flow cytometry, confocal fluorescence, and super-resolution imaging microscopy, and the lateral fluidity was quantified using fluorescence recovery after photobleaching (FRAP) techniques. Under these conditions, the 4-arm-PEG(20,000)-NH2 based configuration gave the most desirable tethering system based on lateral diffusivity and coverage.

The Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling is activated by infections of bacteria, fungi, viruses and parasites and mediated cellular and humoral immune responses. In the pea aphid Acyrthosiphon pisum little is known about the function of JAK/STAT signaling in its immune system. In this study, we first showed that expression of genes in the JAK/STAT signaling, including the receptors Domeless1/2, Janus kinase (JAK) and transcriptional factor Stat92E, is up-regulated upon bacteria Escherichia coli and Staphylococcus aureus and fungus Beauveria bassiana infections. After knockdown of expression of these genes by means of dsRNA injection, the aphids harbored more bacteria and suffered more death after infected with E. coli and S. aureus, but showed no significant change after B. bassiana infection. Our study suggests the JAK/STAT signaling contributes to the defense against bacterial infection in the pea aphid.

CD33 is a transmembrane receptor expressed on cells of myeloid lineage and regulates innate immunity. CD33 is a risk factor for Alzheimer’s disease (AD) and targeting CD33 has been a promising strategy drug development. However, the mechanism of CD33’s action is poorly understood. Here we investigate the mechanism of anti-CD33 antibody HuM195 (Lintuzumab) and its single-chain variable fragment (scFv) and examine their therapeutic potential. Treatment with HuM195 full-length antibody or its scFv increased phagocytosis of β-amyloid 42 (Aβ42) in human microglia and monocytes. This activation of phagocytosis was driven by internalization and degradation of CD33, thereby downregulating its inhibitory signal. HumM195 transiently induced CD33 phosphorylation and its signaling via receptor dimerization. However, this signaling decayed with degradation of CD33. scFv binding to CD33 leads to a degradation of CD33 without detection of the CD33 dimerization and signaling. Moreover, we found that treatments with either HuM195 or scFv promotes the secretion of IL33, a cytokine implicated in microglia reprogramming. Importantly, recombinant IL33 potentiates the uptake of Aβ42 in monocytes. Collectively, our findings provide unanticipated mechanistic insight into the role of CD33 signaling in both monocytes and microglia and define a molecular basis for the development of CD33-based therapy of AD.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by the presence of extracellular amyloid plaques consisting of β-amyloid peptides (Aβ) and intracellular neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau (pTau) protein in the brain. Genetic and animal studies strongly indicate that Aβ, tau and neuroinflammation play important roles in the pathogenesis of AD. Several staging models showed that NFTs correlated well with the disease progression. Positron emission tomography (PET) imaging has become a widely used non-invasive technique to image NFTs for early diagnosis of AD. Despite the remarkable progress made over the past few years, tau PET imaging is still challenging due to the nature of tau pathology and the technical aspects of PET imaging. Tau pathology often coexists with other proteinopathies, such as Aβ plaques and α-synuclein aggregates. Distinguishing tau-specific signals from other overlapping pathologies is difficult, especially in the context of AD, where multiple protein aggregates are present, as well as the spectrum of different tau isoforms (3R and 4R) and conformations. Moreover, tracers should ideally have optimal pharmacokinetic properties to penetrate the blood-brain barrier (BBB) while maintaining specificity, low toxicity, low non-specific binding, rapid uptake and clearance from the brain, and formation of no radiolabeled metabolites in the brain. On the other hand, Parkinson's disease (PD) is a progressive neurodegenerative movement disorder characterized by the abnormal accumulations of α-synuclein in neurons. Heterogeneity and the unclear pathogenesis of PD hinder early and accurate diagnosis of the disease for therapeutic development in clinical use. In this review, while referring to existing reviews, we focus on the design strategies and current progress in tau (NFTs) targeting new PET tracers for AD; evolution of non-AD tau targeting PET tracers for applications including progressive supranuclear paralysis (PSP) and corticobasal degeneration (CBD); new PET tracer development for α-synuclein aggregate imaging in PD and giving an outlook for future PET tracer development.

Innate immunity protein interferon induced transmembrane protein 3 (IFITM3) is a transmembrane protein that has a wide array of functions, including in viral infections, Alzheimer's Disease (AD), and cancer. As an interferon stimulated gene (ISG), IFITM3's expression is upregulated by type-I, II, and III interferons. Moreover, the antiviral activity of IFITM3 is modulated by post-translational modifications. IFITM3 functions in innate immunity to disrupt viral fusion and entry to the plasma membrane as well as prevent viral escape from endosomes. As a γ-secretase modulatory protein, IFITM3 distinctly modulates the processing of amyloid precursor protein (APP) to generate amyloid beta peptides (Aβ) and Notch1 cleavages. Increased IFITM3 expression, which can result from aging, cytokine activation, inflammation, and infection, can lead to an upregulation of γ-secretase for Aβ production that causes a risk of AD. Therefore, the prevention of IFITM3 upregulation has potential in the development of novel therapies for the treatment of AD.

Supplementary Figure 2 from γ-Secretase Inhibitors Abrogate Oxaliplatin-Induced Activation of the Notch-1 Signaling Pathway in Colon Cancer Cells Resulting in Enhanced Chemosensitivity

Abstract Brain metastasis is a significant cause of morbidity and mortality in multiple cancer types and represents an unmet clinical need. The mechanisms that mediate metastatic cancer growth in the brain parenchyma are largely unknown. Melanoma, which has the highest rate of brain metastasis among common cancer types, is an ideal model to study how cancer cells adapt to the brain parenchyma. Our unbiased proteomics analysis of melanoma short-term cultures revealed that proteins implicated in neurodegenerative pathologies are differentially expressed in melanoma cells explanted from brain metastases compared with those derived from extracranial metastases. We showed that melanoma cells require amyloid beta (Aβ) for growth and survival in the brain parenchyma. Melanoma-secreted Aβ activates surrounding astrocytes to a prometastatic, anti-inflammatory phenotype and prevents phagocytosis of melanoma by microglia. Finally, we demonstrate that pharmacologic inhibition of Aβ decreases brain metastatic burden. Significance: Our results reveal a novel mechanistic connection between brain metastasis and Alzheimer's disease, two previously unrelated pathologies; establish Aβ as a promising therapeutic target for brain metastasis; and demonstrate suppression of neuroinflammation as a critical feature of metastatic adaptation to the brain parenchyma. This article is highlighted in the In This Issue feature, p. 1171

Supplementary Figure 3. Representative PET imaging of endogenously developed mammary tumors from MMTVPyMT transgenic mice using [124I]PN67. The tumor location was indicated by red cycles. PET imaging studies were performed at 2h post-injection on a microPET scanner with (bottom panel) or without (top panel) blocking inhibitor (1, 30mg/kg).

Supplementary Table 2. Biodistribution data of [124I]PN67 in non-tumor bearing BALB/c mice at 2h time point post injection. Data is represented as average %ID/g {plus minus} SD with n=5 animals/group.

Microbiota mediate neuroinflammation in a genetic- and sex-specific manner in mice.

Innate immunity is the first line of defense against pathogens, alerting the individual cell and surrounding area to respond to this potential invasion. γ-secretase is a transmembrane protease complex that plays an intricate role in nearly every stage of this innate immune response. Through regulation of pattern recognition receptors (PRR) such as TREM2 and RAGE γ-secretase can modulate pathogen recognition. γ-secretase can act on cytokine receptors such as IFNαR2 and CSF1R to dampen their signaling capacity. While γ-secretase-mediated regulated intramembrane proteolysis (RIP) can further moderate innate immune responses through downstream signaling pathways. Furthermore, γ-secretase has also been shown to be regulated by the innate immune system through cytokine signaling and γ-secretase modulatory proteins such as IFITM3 and Hif-1α. This review article gives an overview of how γ-secretase is implicated in innate immunity and the maintenance of its responses through potentially positive and negative feedback loops.

Amyloid beta (Aß) extracellular deposits are one of the pathohistological hallmarks of Alzheimer’s Disease (AD). In recent years intracellular accumulation of Aß has been linked with early pathogenic mechanisms. Recent reports now associate intracellular Aβ accumulation, and lysosomal disfunction as an early event in the disease, preceding extracellular amyloid-deposits. Today methods to visualize intracellular Aβ accumulation rely on antibody staining or pre-labeled Aβ. There is an outstanding need for live-imaging tools capable of monitoring Aβ dynamics at the cellular level. We have developed an optical sensor that can monitor Aß in live cells transiently. Single wall carbon nanotubes (SWCNT) present advantages as optical sensors owing to their near-infrared emission, as well as photostability and high-sensitivity. SWCNT emission spectra (wavelength ranges of 1100-1150nm) is within the biological transparency window (1000-1700nm) allowing for optimal imaging in live samples. SWCNT were non-covalently biofunctionalized; by which we confer selectivity to Aβ. To obtain intracellular detection we used two cell lines: monocytes (THP-1) and differentiated SH-SY5Y. Cells were incubated with functionalized nanotubes. We utilized near-infrared spectroscopy and hyper-spectral microscopy to obtain spectral response from live-cells. We developed and characterized a new class of bio-functionalized intrinsically photoluminescent SWCNT sensor that can detect Aß via shifting of their intrinsic near-infrared emission wavelength. Our biofunctionalized sensors specifically recognize Aβ in the solution phase, showing a monochromatic center wavelength decrease in a dose-dependent fashion. The reporters show high specificity compared to competing analytes and in serum samples. In cell models, nanosensors accumulate intracellularly and probe Aβ introduced to the cells specifically. Finally, initial through-skull near-IR imaging in-vivo in an AD model (5XFAD), following intracranial injection, show significant decrease in central wavelength in AD mice compared to wild type. The SWCNT sensor provide a framework for dynamically investigating Aβ in live samples. We believe utilizing the nanosensors can enhance the study of Aβ -pathogenic mechanism, structure and molecular function and consequently improve and accelerate effective amyloid-targeted therapies.