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14 pages, 1886 KiB  
Review
Membrane-Type 5 Matrix Metalloproteinase (MT5-MMP): Background and Proposed Roles in Normal Physiology and Disease
by Deepak Jadhav, Anna M. Knapinska, Hongjie Wang and Gregg B. Fields
Biomolecules 2025, 15(8), 1114; https://doi.org/10.3390/biom15081114 - 3 Aug 2025
Viewed by 323
Abstract
The matrix metalloproteinase (MMP) family includes several membrane-bound enzymes. Membrane-type 5 matrix metalloproteinase (MT5-MMP) is unique amongst the MMP family in being primarily expressed in the brain and during development. It is proposed to contribute to synaptic plasticity and is implicated in several [...] Read more.
The matrix metalloproteinase (MMP) family includes several membrane-bound enzymes. Membrane-type 5 matrix metalloproteinase (MT5-MMP) is unique amongst the MMP family in being primarily expressed in the brain and during development. It is proposed to contribute to synaptic plasticity and is implicated in several pathologies, including multiple cancers and Alzheimer’s disease. In cancer, MT5-MMP expression has been correlated to cancer progression, but a distinct mechanistic role has yet to be uncovered. In Alzheimer’s disease, MT5-MMP exhibits pro-amyloidogenic activity, functioning as an η-secretase that cleaves amyloid precursor protein (APP), ultimately generating two synaptotoxic fragments, Aη-α and Aη-β. Several intracellular binding partners for MT5-MMP have been identified, and of these, N4BP2L1, EIG121, BIN1, or TMX3 binding to MT5-MMP results in a significant increase in MT5-MMP η-secretase activity. Beyond direct effects on APP, MT5-MMP may also facilitate APP trafficking to endosomal/lysosomal compartments and enhance proinflammatory responses. Overall, the substrate profile of MT5-MMP has not been well defined, and selective inhibitors of MT5-MMP have not been described. These advances will be needed for further consideration of MT5-MMP as a therapeutic target in Alzheimer’s disease and other pathologies. Full article
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17 pages, 1544 KiB  
Review
Resistance Mechanisms to BCMA Targeting Bispecific Antibodies and CAR T-Cell Therapies in Multiple Myeloma
by Brandon Tedder and Manisha Bhutani
Cells 2025, 14(14), 1077; https://doi.org/10.3390/cells14141077 - 15 Jul 2025
Viewed by 819
Abstract
B-cell maturation antigen (BCMA)-targeted therapies including both chimeric antigen receptor (CAR) T-cell therapies and bispecific antibodies (BsAbs), have revolutionized the treatment landscape for relapsed/refractory multiple myeloma (MM), offering both deep and durable responses, even in heavily pretreated patients. Despite these advances, most patients [...] Read more.
B-cell maturation antigen (BCMA)-targeted therapies including both chimeric antigen receptor (CAR) T-cell therapies and bispecific antibodies (BsAbs), have revolutionized the treatment landscape for relapsed/refractory multiple myeloma (MM), offering both deep and durable responses, even in heavily pretreated patients. Despite these advances, most patients ultimately experience relapse. This is likely related to the development of resistance mechanisms that limit the long-term efficacy and durability of BCMA-targeted approaches. In this review, we examine the current landscape of BCMA-directed therapies, including Idecabtagene Vileucel, Ciltacabtagene Autoleucel, Teclistamab, and Elranatamab and explore the multifactorial mechanisms driving resistance. These mechanisms include tumor-intrinsic factors, host-related and tumor-extrinsic factors, and factors related to the tumor-microenvironment itself. We outline emerging strategies to overcome resistance, such as dual-targeting therapies, γ-secretase inhibitors, immune-checkpoint blockade, armored CAR T constructs, and novel combination regimens. Additionally, we discuss the role of therapy sequencing, emphasizing how prior exposure to BsAbs or CAR T-cell therapies may influence the efficacy of subsequent treatments. A deeper understanding of resistance biology, supported by integrated immune and genomic profiling, is essential to optimizing therapeutic durability and ultimately improve patient outcomes for patients with MM. Full article
(This article belongs to the Special Issue Novel Insights into Molecular Mechanisms and Therapy of Myeloma)
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11 pages, 1801 KiB  
Article
Presenilin-1 Familial Alzheimer Mutations Impair γ-Secretase Cleavage of APP Through Stabilized Enzyme–Substrate Complex Formation
by Sujan Devkota, Masato Maesako and Michael S. Wolfe
Biomolecules 2025, 15(7), 955; https://doi.org/10.3390/biom15070955 - 1 Jul 2025
Viewed by 369
Abstract
Familial Alzheimer’s disease (FAD) is caused by dominant missense mutations in amyloid precursor protein (APP) and presenilin-1 (PSEN1), the catalytic component of γ-secretase that generates amyloid β-peptides (Aβ) from the APP C-terminal fragment C99. While most FAD mutations increase the ratio of aggregation-prone [...] Read more.
Familial Alzheimer’s disease (FAD) is caused by dominant missense mutations in amyloid precursor protein (APP) and presenilin-1 (PSEN1), the catalytic component of γ-secretase that generates amyloid β-peptides (Aβ) from the APP C-terminal fragment C99. While most FAD mutations increase the ratio of aggregation-prone Aβ42 relative to Aβ40, consistent with the amyloid hypothesis of Alzheimer pathogenesis, some mutations do not increase this ratio. The γ-secretase complex produces amyloid β-peptide (Aβ) through processive cleavage along two pathways: C99 → Aβ49 → Aβ46 → Aβ43 → Aβ40 and C99 → Aβ48 → Aβ45 → Aβ42 → Aβ38. Understanding how FAD mutations affect the multistep γ-secretase cleavage process is critical for elucidating disease pathogenesis. In a recent study, we discovered that FAD mutations lead to stalled γ-secretase/substrate complexes that trigger synaptic loss independently of Aβ production. Here, we further investigate this “stalled complex” hypothesis, focusing on five additional PSEN1 FAD mutations (M84V, C92S, Y115H, T116I, and M139V). A comprehensive biochemical analysis revealed that all five mutations led to substantially reduced initial proteolysis of C99 to Aβ49 or Aβ48 as well as deficiencies in one or more subsequent trimming steps. Results from fluorescence lifetime imaging microscopy support increased stabilization of enzyme–substrate complexes by all five FAD mutations. These findings provide further support for the stalled complex hypothesis, highlighting that FAD mutations impair γ-secretase function by promoting the accumulation of stalled enzyme–substrate complexes. Full article
(This article belongs to the Section Biomacromolecules: Proteins, Nucleic Acids and Carbohydrates)
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21 pages, 3384 KiB  
Article
Anti-Inflammatory Peptide Prevents Aβ25–35-Induced Inflammation in Rats via Lipoxygenase Inhibition
by Yudhishthir Yadav, Masroor Anwar, Hanuman Sharma, Suman Jain, Uma Sharma, Partha Haldar, Aparajit B. Dey and Sharmistha Dey
Cells 2025, 14(13), 957; https://doi.org/10.3390/cells14130957 - 23 Jun 2025
Viewed by 691
Abstract
Neuroinflammation, triggered by lipoxygenase (LOX), contributes to Alzheimer’s disease (AD) progression. Overexpression of LOX-5 in patients with AD serum highlights its role. This study assessed the efficacy of the LOX-inhibitor-peptide YWCS in an AD rat model induced by Aβ25–35 injection. Cognitive tests, [...] Read more.
Neuroinflammation, triggered by lipoxygenase (LOX), contributes to Alzheimer’s disease (AD) progression. Overexpression of LOX-5 in patients with AD serum highlights its role. This study assessed the efficacy of the LOX-inhibitor-peptide YWCS in an AD rat model induced by Aβ25–35 injection. Cognitive tests, magnetic resonance imaging (MRI) scans, and molecular analyses were conducted. YWCS treatment significantly improved cognitive function, as evidenced by improved performance in the open field, novel object recognition, elevated plus maze, and Morris water maze tests. MRI scans revealed hippocampal shrinkage in AD rats and no changes were observed from YWCS treatment. Molecular analysis revealed altered expression of LOX-5, LOX-12, Aβ, γ-secretase components, p-Tau181, Akt, p-Akt, and p53 in AD rats. Immunofluorescence staining confirmed increased expression of LOX, Aβ, and p-Tau181 in the hippocampus of AD rats, which was reduced by YWCS treatment. Serum LOX levels were elevated in AD rats and significantly decreased after YWCS treatment, aligning with previous findings in human AD patients and AD cell models. YWCS offered improvements in behavioral and inflammatory marker regulation and also prevented progression of the disease, as shown by MRI results. These results suggest that YWCS, by targeting LOX, has the potential to be a promising therapeutic agent for AD. Full article
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23 pages, 2784 KiB  
Article
DFT-Based Elucidation and Evaluation of Selenium-Modified Tacrine Derivatives: Theoretical and Physicochemical Insights for Alzheimer’s Disease Therapy
by Roberto Barbosa Morais, Manoela do Sacramento, Cecilia Scimmi, Darling de Andrade Lourenço, Frederico Schmitt Kremer, Lucielli Savegnago and Diego Alves
Molecules 2025, 30(12), 2553; https://doi.org/10.3390/molecules30122553 - 11 Jun 2025
Viewed by 622
Abstract
The incorporation of selenium into tacrine derivatives has been explored as a novel strategy to enhance therapeutic efficacy while minimizing toxicity in the treatment of neurodegenerative diseases such as Alzheimer’s. This study utilized computational and experimental approaches, including Density Functional Theory (DFT), molecular [...] Read more.
The incorporation of selenium into tacrine derivatives has been explored as a novel strategy to enhance therapeutic efficacy while minimizing toxicity in the treatment of neurodegenerative diseases such as Alzheimer’s. This study utilized computational and experimental approaches, including Density Functional Theory (DFT), molecular docking, pharmacokinetic profiling, and toxicological predictions, to evaluate the potential of these derivatives. The selenium-modified compounds demonstrated improved electronic properties, such as narrower HOMO–LUMO gaps and optimized electronegativity, resulting in enhanced stability and reactivity. Pharmacokinetic analyses revealed favorable absorption, distribution, and blood–brain barrier penetration, while toxicological assessments indicated reduced hepatotoxicity and skin sensitization risks compared to tacrine. Molecular docking and dynamic simulations highlighted strong and stable interactions of the derivatives with critical enzymes, including acetylcholinesterase (AChE) and beta-secretases (BACE1 and BACE2). Compounds 12 and 13, in particular, emerged as the most promising candidates due to their superior stability and binding affinity. These findings underscore the potential of selenium-modified tacrine derivatives as safer and more effective therapeutic agents for Alzheimer’s disease, warranting further experimental validation. Full article
(This article belongs to the Special Issue Recent Advances in Organochalcogen Chemistry)
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16 pages, 6371 KiB  
Article
BACE1 Inhibition Protects Against Type 2 Diabetes Mellitus by Restoring Insulin Receptor in Mice
by Tingting Lin, Ting Liang, Yong Shen and Feng Gao
Int. J. Mol. Sci. 2025, 26(11), 5100; https://doi.org/10.3390/ijms26115100 - 26 May 2025
Cited by 1 | Viewed by 556
Abstract
β-secretase 1 (BACE1), known for its role in amyloid-β production associated with Alzheimer’s disease (AD), has also been suggested to be elevated in patients with Type 2 diabetes mellitus (T2DM). Notably, BACE1 could cleave the insulin receptor (InsR), leading to reduced InsR levels, [...] Read more.
β-secretase 1 (BACE1), known for its role in amyloid-β production associated with Alzheimer’s disease (AD), has also been suggested to be elevated in patients with Type 2 diabetes mellitus (T2DM). Notably, BACE1 could cleave the insulin receptor (InsR), leading to reduced InsR levels, which may impair insulin signaling and contribute to insulin resistance. Presently, we observed decreased InsR levels and impaired glucose disposal in the livers of mice with systemic overexpression of BACE1 (HUBC mice). This suggests that elevated BACE1 could contribute to insulin resistance by shedding membrane InsR. Additionally, mice fed a high-fat diet (HFD), a well-established model of T2DM, displayed increased BACE1 levels and decreased InsR. To further investigate whether inhibiting BACE1 could enhance insulin sensitivity and alleviate symptoms of diabetes, we treated HFD mice with the BACE1 inhibitor Elenbecestat. Remarkably, the administration of Elenbecestat restored InsR levels and improved their downstream signaling pathways, leading to increased insulin sensitivity and enhanced glucose tolerance. In summary, our findings suggest that inhibiting BACE1 can restore InsR expression and improve insulin-signaling sensitivity, ultimately resulting in enhanced diabetic phenotypes. Full article
(This article belongs to the Section Molecular Endocrinology and Metabolism)
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11 pages, 1586 KiB  
Article
Endogenous γ-Secretase Is Linked to Phagocytic Activity in Microglial Cells
by Emily Williams, Mei C. Q. Houser, Sebastian Torres, Natalia Wieckiewicz, Michael Sadek, Midori Yokomizo and Masato Maesako
Sensors 2025, 25(11), 3298; https://doi.org/10.3390/s25113298 - 24 May 2025
Viewed by 623
Abstract
γ-Secretase has primarily been studied in neurons, whereas increasing evidence highlights its importance in microglia. Previous research has shown that the pharmacological inhibition of γ-secretase impairs microglial phagocytic activity. In this study, we used a genetically encoded Förster resonance energy transfer (FRET)-based biosensor [...] Read more.
γ-Secretase has primarily been studied in neurons, whereas increasing evidence highlights its importance in microglia. Previous research has shown that the pharmacological inhibition of γ-secretase impairs microglial phagocytic activity. In this study, we used a genetically encoded Förster resonance energy transfer (FRET)-based biosensor to record γ-secretase activity, aiming to determine if naturally occurring cell-by-cell variations in endogenous γ-secretase activity are associated with phagocytic activity. Using the Notch1 N100 Y-T biosensor, we found that the regulation of endogenous γ-secretase activity varies among individual BV-2 microglial cells. Our multiplexed time-lapse imaging revealed that the phagocytosis of E. coli bioparticles was impaired in cells with lower γ-secretase activity compared to those with higher activity. Complementary biochemical analysis, utilizing Zymosan bioparticles and fluorescence-activated cell sorting (FACS), further demonstrated that cells with reduced phagocytic activity exhibited decreased endogenous γ-secretase activity. Collectively, our confirmatory study supports previous findings that microglial phagocytic activity is closely linked to γ-secretase and emphasizes the essential role of γ-secretase in microglia. Full article
(This article belongs to the Special Issue Fluorescence Sensors for Biological and Medical Applications)
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26 pages, 11403 KiB  
Article
Unveiling the Polypharmacological Potency of FDA-Approved Rebamipide for Alzheimer’s Disease
by Israa J. Hakeem, Hadil Alahdal, Hanadi M. Baeissa, Tahani Bakhsh, Misbahuddin Rafeeq, Alaa Hamed Habib, Mohammed Matoog Karami, Maryam A. AL-Ghamdi, Ghadeer Abdullah and Abeer Al Tuwaijri
Pharmaceuticals 2025, 18(6), 772; https://doi.org/10.3390/ph18060772 - 22 May 2025
Viewed by 723
Abstract
Background: Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder characterised by the accumulation of neurotoxic substances in the brain, ultimately leading to progressive cognitive decline. The complex aetiology and involvement of multiple molecular targets in AD pathogenesis have made discovering effective therapeutic agents [...] Read more.
Background: Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder characterised by the accumulation of neurotoxic substances in the brain, ultimately leading to progressive cognitive decline. The complex aetiology and involvement of multiple molecular targets in AD pathogenesis have made discovering effective therapeutic agents particularly challenging. Targeting multiple proteins simultaneously with a single therapeutic agent may offer a promising strategy to address the disease’s multifaceted nature. Methods: This study employed advanced computational methodologies to perform multitargeted molecular docking of FDA-approved drugs against four key AD-associated proteins implicated in disease progression. Among the screened compounds, Rebamipide—a drug conventionally used for treating gastrointestinal disorders—demonstrated notable binding affinities across all targets. Pharmacokinetic predictions, interaction fingerprinting, WaterMap analysis, density functional theory (DFT) calculations, and 100 ns MD simulations were performed for each protein–ligand complex to evaluate its multitarget potential. Results: Rebamipide bound effectively to the NR1 ligand-binding core, suggesting modulation of glutamatergic signalling while reducing β-secretase production and regulating neurotransmitter homeostasis through inhibiting monoamine oxidase-A. Furthermore, Rebamipide enhanced cholinergic neurotransmission by inhibiting human acetylcholinesterase, potentially improving cognitive function. Pharmacokinetic analyses confirmed favourable drug-like properties. Molecular interaction fingerprints revealed consistent hydrogen bonding, hydrophobic contacts, and π-π stacking interactions. WaterMap analysis indicated thermodynamically favourable water displacement upon binding, enhancing ligand affinity. DFT analysis of Rebamipide showed a 4.24 eV HOMO-LUMO gap, with ESP values ranging from −6.63 × 10−2 to +6.63 × 10−2 A.U., indicating reactive sites. TDDFT predicted strong UV absorption at 314 nm with a peak intensity of ~6500 L mol−1 cm−1. MD simulations over 100 ns demonstrated minimal structural deviations and stable ligand–protein complexes, reinforcing its multitarget efficacy. Conclusions: The comprehensive in silico investigation highlights Rebamipide as a promising multitargeted therapeutic candidate for Alzheimer’s disease. Its ability to modulate multiple pathogenic pathways simultaneously underscores its potential utility; however, these computational findings warrant further experimental validation to confirm its efficacy and therapeutic relevance in AD. Full article
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23 pages, 7972 KiB  
Article
Short Tandem Repeat (STR) Somatic Mutation in Non-Melanoma Skin Cancer (NMSC): Association with Transcriptomic Profile and Potential Implications for Therapy
by Muhammad G. Kibriya, Armando Almazan, Maria Argos, Tariqul Islam, Christopher R. Shea, Habibul Ahsan and Farzana Jasmine
Cancers 2025, 17(10), 1669; https://doi.org/10.3390/cancers17101669 - 15 May 2025
Viewed by 681
Abstract
Background: Studies on somatic mutations in cancer typically report single-nucleotide variants in coding regions, while mutations in short tandem repeats (STRs) are usually overlooked. Homopolymeric regions, a subset of STRs, are stretches of DNA where only a single nucleotide is repeated multiple times [...] Read more.
Background: Studies on somatic mutations in cancer typically report single-nucleotide variants in coding regions, while mutations in short tandem repeats (STRs) are usually overlooked. Homopolymeric regions, a subset of STRs, are stretches of DNA where only a single nucleotide is repeated multiple times (e.g., AAAAA or TTTTT). Only recently have mutations in such STR regions been seen in colorectal cancer, where microsatellite instability (MSI) is common. In non-melanoma skin cancer (NMSC), MSI is rare. In this study, we focus on somatic mutations in such homopolymeric regions in NMSC and their functional implications. Methods: We performed targeted DNA sequencing (paired tissue and blood from the same individual), using more than 400 cancer-related genes from 32 NMSC patients as cases and non-lesional skin tissue from 16 independent individuals as controls. Results: We identified NMSC-associated STR somatic mutations. These are associated with the dysregulation of DNA damage and repair mechanisms. In artificial intelligence (AI) predictive modeling, these markers could successfully differentiate basal cell carcinoma (BCC) and non-lesional skin tissue. To our knowledge, we present the first study focusing on STR somatic mutations in multiple cancer-related genes in NMSC found only in tumor tissue and not in non-lesional skin tissue. Some of them (APC, BRAF) are associated with more pronounced dysregulation of relevant gene pathways (hedgehog, Notch signaling, and Wnt signaling). Conclusions: Our findings suggest that this STR somatic mutation status might potentially be used to select BCC patients who could benefit from certain precision therapy including hedgehog inhibitors, gamma-secretase inhibitors, anti-Vasuclar endothelial growth factor (VEGF), proteasome inhibitors, and immune check-point inhibitors. Full article
(This article belongs to the Special Issue Advances in Genetic and Molecular Approaches to Skin Cancer)
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43 pages, 6701 KiB  
Review
Alleviation of Neurological Disorders by Targeting Neurodegenerative-Associated Enzymes: Natural and Synthetic Molecules
by Alka Ashok Singh, Fazlurrahman Khan and Minseok Song
Int. J. Mol. Sci. 2025, 26(10), 4707; https://doi.org/10.3390/ijms26104707 - 14 May 2025
Viewed by 1299
Abstract
Neurological disorders, encompassing neurodegenerative and neuroinflammatory conditions, present significant public health and clinical challenges. Recent research has elucidated the pivotal role of various enzymes in the onset and progression of these disorders. This review explores the therapeutic potential of targeting these enzymes with [...] Read more.
Neurological disorders, encompassing neurodegenerative and neuroinflammatory conditions, present significant public health and clinical challenges. Recent research has elucidated the pivotal role of various enzymes in the onset and progression of these disorders. This review explores the therapeutic potential of targeting these enzymes with natural and synthetic molecules. Key enzymes, including acetylcholinesterase, monoamine oxidase, beta-secretase, tau kinases, caspases, and cyclooxygenase-2, are implicated in diseases such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. Modulating these enzymes can alleviate symptoms, slow disease progression, or reverse pathological changes. Natural molecules derived from plants, microbes, seaweeds, and animals have long been noted for their therapeutic potential. Their ability to interact with specific enzymes with high specificity and minimal side effects makes them promising candidates for treatment. These natural agents provide a foundation for developing targeted therapies with improved safety profiles. Simultaneously, the development of synthetic chemistry has resulted in molecules designed to inhibit neurodegenerative enzymes with precision. This review examines the progress in creating small molecules, peptides, and enzyme inhibitors through sophisticated drug design techniques. It evaluates the efficacy, safety, and mechanisms of these synthetic agents, highlighting their potential for clinical application. The review offers a comprehensive overview of recent advancements in enzyme-targeted therapies for neurological disorders, covering both natural and synthetic molecules investigated in preclinical and clinical settings. It discusses the mechanisms through which these molecules exert their effects, the challenges faced in their development, and future research directions. By synthesizing current knowledge, this paper aims to illuminate the potential of enzyme-targeted interventions in managing neurological disorders, showcasing both the promise and limitations of these approaches. Full article
(This article belongs to the Section Molecular Neurobiology)
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17 pages, 788 KiB  
Review
Amyloid β-Induced Inflammarafts in Alzheimer’s Disease
by Shihui Ding, Soo-Ho Choi and Yury I. Miller
Int. J. Mol. Sci. 2025, 26(10), 4592; https://doi.org/10.3390/ijms26104592 - 10 May 2025
Cited by 1 | Viewed by 936
Abstract
The formation of amyloid beta (Aβ) plaques is a central process in the development of Alzheimer’s disease (AD). Although its causative role or the effectiveness of therapeutic targeting is still debated, the key involvement of Aβ in the pathogenesis of neuroinflammation and neurodegeneration [...] Read more.
The formation of amyloid beta (Aβ) plaques is a central process in the development of Alzheimer’s disease (AD). Although its causative role or the effectiveness of therapeutic targeting is still debated, the key involvement of Aβ in the pathogenesis of neuroinflammation and neurodegeneration in AD is broadly accepted. In this review, we emphasize the role of lipid rafts, both in APP cleavage producing Aβ in neurons and in mediating Aβ inflammatory signaling in microglia. We introduce the term inflammarafts to characterize the Aβ-driven formation of enlarged, cholesterol-rich lipid rafts in activated microglia, which support protein–protein and lipid–protein interactions of inflammatory receptors. Examples reviewed include toll-like receptors (TLR2, TLR4), scavenger receptors (CD36, RAGE), and TREM2. The downstream pathways lead to the production of cytokines and reactive oxygen species, intensifying neuroinflammation and resulting in neuronal injury and cognitive decline. We further summarize emerging therapeutic strategies and emphasize the utility of apolipoprotein A-I binding protein (AIBP) in selective targeting of inflammarafts and attenuation of microglia-driven inflammation. Unlike the targeting of a single inflammatory receptor or a secretase, selective disruption of inflammarafts and preservation of physiological lipid rafts offer a novel approach to targeting multiple components and processes that contribute to neuroinflammation in AD. Full article
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17 pages, 2758 KiB  
Article
Preventive Effect of Probiotic Leuconostoc mesenteroides H40 Against Cognitive Disorder by Anti-Inflammatory, Synaptic Plasticity Regulation, and Antioxidant Effects
by Na-Kyoung Lee, Yunjung Lee, Minhye Won, Nayeong Kim, Eunju Park and Hyun-Dong Paik
Antioxidants 2025, 14(5), 565; https://doi.org/10.3390/antiox14050565 - 8 May 2025
Viewed by 624
Abstract
Live Leuconostoc mesenteroides H40 has been reported to have probiotic properties; however, the effect of its live probiotic form on cognitive ability has not been reported. This study investigated modulatory effects of the probiotic L. mesenteroides H40 in an ICR mouse model (male) [...] Read more.
Live Leuconostoc mesenteroides H40 has been reported to have probiotic properties; however, the effect of its live probiotic form on cognitive ability has not been reported. This study investigated modulatory effects of the probiotic L. mesenteroides H40 in an ICR mouse model (male) of cognitive disorders. Cognitive disorders were induced in mice by the addition of scopolamine (1 mg/kg/day) with donepezil (2 mg/kg/day) as a medicinal control. L. mesenteroides H40 significantly attenuated scopolamine-induced cognitive disorder in the novel object recognition and Y-maze tests in a concentration-dependent manner. L. mesenteroides H40 decreased amyloid β levels, but increased β-secretase levels. The mRNA expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 significantly decreased following L. mesenteroides H40 treatment. Additionally, TNF-α, IL-1β, and PGE2 protein expression was decreased. Acetylcholine, acetylcholinesterase, choline acetyltransferase, brain-derived neurotrophic factor (BDNF), and cAMP response element-binding protein (CREB) levels were increased in the brain tissues. The antioxidant effects of superoxide dismutase, catalase, and glutathione peroxidase were also alleviated. We demonstrated that L. mesenteroides H40 exhibits neuroprotective effects through anti-inflammatory, synaptic plasticity regulation, and antioxidant effects. Thus, the probiotic L. mesenteroides H40 could be used as a prophylactic functional food for cognitive disorders. Full article
(This article belongs to the Section Health Outcomes of Antioxidants and Oxidative Stress)
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136 pages, 24434 KiB  
Perspective
Alzheimer’s Is a Multiform Disease of Sustained Neuronal Integrated Stress Response Driven by the C99 Fragment Generated Independently of AβPP; Proteolytic Production of Aβ Is Suppressed in AD-Affected Neurons: Evolution of a Theory
by Vladimir Volloch and Sophia Rits-Volloch
Int. J. Mol. Sci. 2025, 26(9), 4252; https://doi.org/10.3390/ijms26094252 - 29 Apr 2025
Viewed by 1349
Abstract
The present Perspective analyzes the remarkable evolution of the Amyloid Cascade Hypothesis 2.0 (ACH2.0) theory of Alzheimer’s disease (AD) since its inception a few years ago, as reflected in the diminishing role of amyloid-beta (Aβ) in the disease. In the initial iteration of [...] Read more.
The present Perspective analyzes the remarkable evolution of the Amyloid Cascade Hypothesis 2.0 (ACH2.0) theory of Alzheimer’s disease (AD) since its inception a few years ago, as reflected in the diminishing role of amyloid-beta (Aβ) in the disease. In the initial iteration of the ACH2.0, Aβ-protein-precursor (AβPP)-derived intraneuronal Aβ (iAβ), accumulated to neuronal integrated stress response (ISR)-eliciting levels, triggers AD. The neuronal ISR, in turn, activates the AβPP-independent production of its C99 fragment that is processed into iAβ, which drives the disease. The second iteration of the ACH2.0 stemmed from the realization that AD is, in fact, a disease of the sustained neuronal ISR. It introduced two categories of AD—conventional and unconventional—differing mainly in the manner of their causation. The former is caused by the neuronal ISR triggered by AβPP-derived iAβ, whereas in the latter, the neuronal ISR is elicited by stressors distinct from AβPP-derived iAβ and arising from brain trauma, viral and bacterial infections, and various types of inflammation. Moreover, conventional AD always contains an unconventional component, and in both forms, the disease is driven by iAβ generated independently of AβPP. In its third, the current, iteration, the ACH2.0 posits that proteolytic production of Aβ is suppressed in AD-affected neurons and that the disease is driven by C99 generated independently of AβPP. Suppression of Aβ production in AD seems an oxymoron: Aβ is equated with AD, and the later is inconceivable without the former in an ingrained Amyloid Cascade Hypothesis (ACH)-based notion. But suppression of Aβ production in AD-affected neurons is where the logic leads, and to follow it we only need to overcome the inertia of the preexisting assumptions. Moreover, not only is the generation of Aβ suppressed, so is the production of all components of the AβPP proteolytic pathway. This assertion is not a quantum leap (unless overcoming the inertia counts as such): the global cellular protein synthesis is severely suppressed under the neuronal ISR conditions, and there is no reason for constituents of the AβPP proteolytic pathway to be exempted, and they, apparently, are not, as indicated by the empirical data. In contrast, tau protein translation persists in AD-affected neurons under ISR conditions because the human tau mRNA contains an internal ribosomal entry site in its 5′UTR. In current mouse models, iAβ derived from AβPP expressed exogenously from human transgenes elicits the neuronal ISR and thus suppresses its own production. Its levels cannot principally reach AD pathology-causing levels regardless of the number of transgenes or the types of FAD mutations that they (or additional transgenes) carry. Since the AβPP-independent C99 production pathway is inoperative in mice, the current transgenic models have no potential for developing the full spectrum of AD pathology. What they display are only effects of the AβPP-derived iAβ-elicited neuronal ISR. The paper describes strategies to construct adequate transgenic AD models. It also details the utilization of human neuronal cells as the only adequate model system currently available for conventional and unconventional AD. The final alteration of the ACH2.0, introduced in the present Perspective, is that AβPP, which supports neuronal functionality and viability, is, after all, potentially produced in AD-affected neurons, albeit not conventionally but in an ISR-driven and -compatible process. Thus, the present narrative begins with the “omnipotent” Aβ capable of both triggering and driving the disease and ends up with this peptide largely dislodged from its pedestal and retaining its central role in triggering the disease in only one, although prevalent (conventional), category of AD (and driving it in none). Among interesting inferences of the present Perspective is the determination that “sporadic AD” is not sporadic at all (“non-familial” would be a much better designation). The term has fatalistic connotations, implying that the disease can strike at random. This is patently not the case: The conventional disease affects a distinct subpopulation, and the basis for unconventional AD is well understood. Another conclusion is that, unless prevented, the occurrence of conventional AD is inevitable given a sufficiently long lifespan. This Perspective also defines therapeutic directions not to be taken as well as auspicious ways forward. The former category includes ACH-based drugs (those interfering with the proteolytic production of Aβ and/or depleting extracellular Aβ). They are legitimate (albeit inefficient) preventive agents for conventional AD. There is, however, a proverbial snowball’s chance in hell of them being effective in symptomatic AD, lecanemab, donanemab, and any other “…mab” or “…stat” notwithstanding. They comprise Aβ-specific antibodies, inhibitors of beta- and gamma-secretase, and modulators of the latter. In the latter category, among ways to go are the following: (1) Depletion of iAβ, which, if sufficiently “deep”, opens up a tantalizing possibility of once-in-a-lifetime preventive transient treatment for conventional AD and aging-associated cognitive decline, AACD. (2) Composite therapy comprising the degradation of C99/iAβ and concurrent inhibition of the neuronal ISR. A single transient treatment could be sufficient to arrest the progression of conventional AD and prevent its recurrence for life. Multiple recurrent treatments would achieve the same outcome in unconventional AD. Alternatively, the sustained reduction/removal of unconventional neuronal ISR-eliciting stressors through the elimination of their source would convert unconventional AD into conventional one, preventable/treatable by a single transient administration of the composite C99/iAβ depletion/ISR suppression therapy. Efficient and suitable ISR inhibitors are available, and it is explicitly clear where to look for C99/iAβ-specific targeted degradation agents—activators of BACE1 and, especially, BACE2. Directly acting C99/iAβ-specific degradation agents such as proteolysis-targeting chimeras (PROTACs) and molecular-glue degraders (MGDs) are also viable options. (3) A circumscribed shift (either upstream or downstream) of the position of transcription start site (TSS) of the human AβPP gene, or, alternatively, a gene editing-mediated excision or replacement of a small, defined segment of its portion encoding 5′-untranslated region of AβPP mRNA; targeting AβPP RNA with anti-antisense oligonucleotides is another possibility. If properly executed, these RNA-based strategies would not interfere with the protein-coding potential of AβPP mRNA, and each would be capable of both preventing and stopping the AβPP-independent generation of C99 and thus of either preventing AD or arresting the progression of the disease in its conventional and unconventional forms. The paper is interspersed with “validation” sections: every conceptually significant notion is either validated by the existing data or an experimental procedure validating it is proposed. Full article
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16 pages, 3788 KiB  
Article
Bacteroides fragilis Toxin Induces Sequential Proteolysis of E-Cadherin and Inflammatory Response in Mouse Intestinal Epithelial Cell Line
by Woo-Seung Kim, Soonjae Hwang, Sun-Yeong Gwon, Minjeong Jo, Sang-Hyeon Yoo, Jiyun Hong, Ha-Neul Jang, Ju-Eun Hong, Da-Hye Kang, Miyong Yun and Ki-Jong Rhee
Microorganisms 2025, 13(4), 781; https://doi.org/10.3390/microorganisms13040781 - 28 Mar 2025
Cited by 1 | Viewed by 801
Abstract
Enterotoxigenic Bacteroides fragilis (ETBF) is an intestinal bacterium that secretes the metalloprotease Bacteroides fragilis toxin (BFT), which induces E-cadherin cleavage and interleukin-8 secretion in human intestinal epithelial cell lines. ETBF-induced E-cadherin cleavage is proposed to be the underlying reason for the promotion of [...] Read more.
Enterotoxigenic Bacteroides fragilis (ETBF) is an intestinal bacterium that secretes the metalloprotease Bacteroides fragilis toxin (BFT), which induces E-cadherin cleavage and interleukin-8 secretion in human intestinal epithelial cell lines. ETBF-induced E-cadherin cleavage is proposed to be the underlying reason for the promotion of colitis in ETBF-infected mice. However, a BFT-responsive murine cell line has not yet been reported. In the current study, we report that the mouse colonic epithelial cell line CMT93 undergoes E-cadherin ectodomain cleavage, cell rounding, and proliferation in response to BFT treatment. The amino acid sequence of the putative cleavage site of E-cadherin is identical in both BFT-responsive (CMT93) and BFT-nonresponsive (MSIE, CT26, YAMC, and B16) cell lines, suggesting that the E-cadherin amino acid sequence is not responsible for this observation. After E-cadherin ectodomain cleavage, the membrane-bound intracellular E-cadherin domain underwent cleavage by γ-secretase and was subsequently degraded by the proteasome. Moreover, BFT induced the secretion of two chemokines (LIX and KC) and the formation of soluble TNFR1 in the CMT93 cell line. The identification of a BFT-responsive murine cell line may be used to elucidate the mechanism of ETBF pathogenesis in ETBF murine infection models. Full article
(This article belongs to the Collection Feature Papers in Medical Microbiology)
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21 pages, 3917 KiB  
Article
Cannabinerol Restores mRNA Splicing Defects Induced by β-Amyloid in an In Vitro Model of Alzheimer’s Disease: A Transcriptomic Study
by Maria Lui, Stefano Salamone, Federica Pollastro, Emanuela Mazzon and Osvaldo Artimagnella
Int. J. Mol. Sci. 2025, 26(7), 3113; https://doi.org/10.3390/ijms26073113 - 28 Mar 2025
Viewed by 637
Abstract
Alzheimer’s disease (AD) is the most common form of dementia, characterized by β-amyloid (Aβ) plaques and neurofibrillary tangles, leading to neuronal loss and cognitive impairments. Recent studies have reported the dysregulation of RNA splicing in AD pathogenesis. Our previous transcriptomic study demonstrated the [...] Read more.
Alzheimer’s disease (AD) is the most common form of dementia, characterized by β-amyloid (Aβ) plaques and neurofibrillary tangles, leading to neuronal loss and cognitive impairments. Recent studies have reported the dysregulation of RNA splicing in AD pathogenesis. Our previous transcriptomic study demonstrated the neuroprotective effect of the phytocannabinoid cannabinerol (CBNR) against the cell viability loss induced by Aβ in differentiated SH-SY5Y cells. This study also highlighted the deregulation of genes involved in mRNA splicing after Aβ exposure or CBNR pre-treatment. Here, we investigated whether CBNR could restore the splicing defects induced by Aβ in an AD in vitro model. Using the rMATS computational tool for detecting differential alternative splicing events (DASEs) from RNA-Seq data, we obtained 96 DASEs regulated in both conditions and, remarkably, they were all restored by CBNR pre-treatment. The pathway analysis indicated an over-representation of the “Alzheimer’s disease–amyloid secretase pathway”. Additionally, we observed that Aβ exposure increased the frequency of retained introns (RIs) among the shared DASEs, and that this frequency returned to normality by CBNR pre-treatment. Interestingly, most of these RIs contain a premature in-frame stop codon within the RNA sequence. Finally, analyzing the DASE regions for miRNA hybridization, we found 33 potential DASE/miRNA interactions that were relevant in AD pathogenesis. These findings revealed a novel trans-gene regulation by CBNR, potentially explaining part of its neuroprotective role. This is the first study demonstrating the involvement of a cannabinoid in the regulation of mRNA splicing in an AD model. Full article
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