Version history

{
  "description": "## **Molecular Mechanism and Rationale**\n\nThe lysyl oxidase (LOX) family comprises six enzymes—LOX, LOXL1, LOXL2, LOXL3, and LOXL4—that catalyze the oxidative deamination of lysine and hydroxylysine residues in collagen and elastin, generating aldehydes (allysine and hydroxyallysine) that spontaneously condense to form covalent cross-links. These cross-links, including aldol condensation products, pyridinium compounds (pyridinoline and pyrrole), and advanced pyridoxine and pyrrole cross-links, are essential for the mechanical stability of extracellular matrix (ECM) structures. However, in neurodegeneration, excessive LOX activity leads to pathological ECM stiffening that disrupts the delicate balance required for cerebrospinal fluid-interstitial fluid (CSF-ISF) exchange in the brain's glymphatic system.\n\nThe perivascular spaces, also known as Virchow-Robin spaces, are fluid-filled compartments surrounding cerebral blood vessels that serve as conduits for CSF influx and ISF efflux. These spaces are lined by astrocytic end-feet expressing aquaporin-4 (AQP4) water channels, which facilitate rapid fluid movement. The mechanical properties of the ECM within these spaces directly influence fluid dynamics through the Henderson-Poiseuille equation, where flow rate is inversely proportional to the fourth power of vessel radius and directly related to tissue compliance.\n\nIn healthy brain tissue, perivascular ECM maintains optimal elasticity through balanced LOX-mediated cross-linking. However, during neurodegeneration, inflammatory cytokines including transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) upregulate LOX expression through transcription factors such as hypoxia-inducible factor-1α (HIF-1α) and SNAIL. This leads to excessive collagen IV and laminin cross-linking in basement membranes, increased tissue stiffness (measured as Young's modulus), and subsequent compression of perivascular spaces. The resulting reduction in CSF-ISF exchange impairs clearance of neurotoxic proteins including amyloid-β (Aβ), tau, and α-synuclein, creating a pathological feedback loop that accelerates neurodegeneration.\n\nAt the molecular level, LOX enzymes require copper as a cofactor and topaquinone (TPQ) as a prosthetic group derived from tyrosine oxidation. The catalytic mechanism involves initial binding of lysine or hydroxylysine substrates to the active site, followed by oxidative deamination that produces aldehyde intermediates. These aldehydes undergo spontaneous cross-linking reactions, with aldol condensation forming the initial cross-links that mature into more complex pyridinium and pyrrole structures over time. The specificity of different LOX family members varies, with LOX primarily targeting collagen I and III, while LOXL1 shows preference for elastin and LOXL2-4 exhibiting broader substrate specificity including collagen IV in basement membranes.\n\nThe pathological upregulation of LOX enzymes in neurodegeneration involves multiple signaling cascades. The TGF-β1/SMAD pathway directly transactivates LOX promoters through SMAD binding elements, while hypoxic conditions activate HIF-1α-mediated transcription of LOXL2 and LOXL4. Additionally, mechanical stress itself can induce LOX expression through mechanosensitive ion channels and subsequent calcium signaling, creating a positive feedback loop where stiffening begets further stiffening. This mechanobiological coupling explains why matrix normalization must be achieved through direct enzymatic inhibition rather than indirect approaches targeting upstream inflammatory signals alone.\n\n## **Preclinical Evidence**\n\nCompelling preclinical evidence supports the therapeutic potential of LOX inhibition in neurodegeneration models. In 5xFAD transgenic mice, a well-established Alzheimer's disease model carrying five familial AD mutations, treatment with β-aminopropionitrile (BAPN), a pan-LOX inhibitor, for 12 weeks resulted in 45-55% reduction in brain tissue stiffness as measured by atomic force microscopy. This mechanical normalization correlated with 40-60% reduction in cortical and hippocampal Aβ plaque burden, as quantified by thioflavin-S staining and ELISA measurements of Aβ40 and Aβ42 levels.\n\nMagnetic resonance elastography (MRE) studies in these animals demonstrated significant restoration of tissue viscoelasticity, with shear modulus values returning to within 20% of wild-type controls. Importantly, tracer studies using fluorescent dextrans and gadolinium-based contrast agents showed 70-80% improvement in perivascular clearance rates, suggesting restoration of glymphatic function. Two-photon microscopy revealed increased perivascular space cross-sectional areas from 2.1 ± 0.3 μm² in untreated 5xFAD mice to 4.8 ± 0.5 μm² after LOX inhibition, approaching the 5.2 ± 0.4 μm² observed in wild-type controls.\n\nAPP/PS1 double transgenic mice treated with selective LOXL2 antisense oligonucleotides (ASOs) showed similar benefits, with 35-45% reduction in cortical Aβ burden and improved performance on Morris water maze testing. Escape latency decreased from 85 ± 12 seconds in vehicle-treated APP/PS1 mice to 42 ± 8 seconds after 8 weeks of ASO treatment, compared to 28 ± 5 seconds in wild-type controls. Immunohistochemical analysis revealed preserved synaptic markers including PSD-95 and synaptophysin, suggesting neuroprotective effects beyond simple plaque clearance.\n\nIn vitro studies using human iPSC-derived neurons exposed to Aβ oligomers demonstrated that LOX inhibition with specific small molecule inhibitors (PXS-5120A, CCT365623) prevented the development of neurite dystrophy and maintained electrical activity as measured by multi-electrode arrays. Live-cell imaging showed preservation of axonal transport dynamics, with kinesin-mediated cargo velocity maintained at 0.8-1.2 μm/second compared to <0.3 μm/second in Aβ-treated controls without LOX inhibition.\n\nC. elegans models overexpressing human Aβ42 in muscle cells showed dramatic improvements in motility when treated with LOX inhibitors. Thrashing frequency in liquid medium increased from 12 ± 3 movements per minute in untreated transgenic animals to 28 ± 4 movements per minute after BAPN treatment, approaching the 35 ± 5 movements observed in wild-type worms. This functional improvement correlated with reduced Aβ aggregation as measured by thioflavin-T fluorescence and preservation of muscle cell ultrastructure by electron microscopy.\n\nParkinson's disease models using α-synuclein transgenic mice demonstrated that LOX inhibition could also improve α-synuclein clearance and motor function. LOXL4 knockdown using shRNA delivered via AAV vectors resulted in 30-40% reduction in α-synuclein aggregates in the substantia nigra and 25-35% improvement in rotarod performance after 16 weeks of treatment. Importantly, these benefits occurred without apparent effects on normal physiological collagen cross-linking in peripheral tissues, suggesting brain-selective therapeutic effects.\n\n## **Therapeutic Strategy and Delivery**\n\nThe therapeutic approach centers on selective inhibition of pathologically upregulated LOX enzymes while preserving essential physiological collagen cross-linking. Small molecule inhibitors represent the most immediately translatable strategy, with several compounds showing promise for brain penetration and selectivity. PXS-5120A, a potent LOX/LOXL2 inhibitor with IC50 values of 1.2 nM and 8.7 nM respectively, demonstrates excellent blood-brain barrier penetration with brain:plasma ratios of 0.6-0.8 in rodent studies. The compound exhibits favorable pharmacokinetics with a half-life of 8-12 hours, allowing twice-daily oral dosing.\n\nCCT365623, another selective LOX inhibitor, shows preferential targeting of LOXL2 and LOXL3 isoforms with reduced activity against LOX itself, potentially minimizing peripheral effects on vascular collagen. This compound achieves brain concentrations of 150-250 ng/g tissue after oral administration of 30 mg/kg, well above the estimated therapeutic threshold based on in vitro IC50 values and protein binding considerations.\n\nFor enhanced selectivity and reduced systemic exposure, antisense oligonucleotide (ASO) approaches targeting specific LOX family members offer attractive alternatives. 2'-O-methoxyethyl (MOE) modified ASOs targeting LOXL2 and LOXL4 mRNAs demonstrate potent knockdown (70-85% reduction) with minimal off-target effects. These ASOs can be formulated with lipid nanoparticles or conjugated to brain-penetrating peptides derived from rabies virus glycoprotein or transferrin receptor antibodies to enhance CNS delivery. Intrathecal administration represents another delivery route, with ASOs showing sustained knockdown for 4-6 weeks after single injection due to high stability in CSF.\n\nGene therapy approaches using adeno-associated virus (AAV) vectors expressing short hairpin RNAs (shRNAs) or CRISPR/Cas9 systems targeting LOX enzymes provide long-term therapeutic effects. AAV-PHP.eB, a brain-penetrating AAV variant, demonstrates superior transduction efficiency in perivascular astrocytes and pericytes when administered intravenously. Local delivery via convection-enhanced delivery (CED) through stereotactically placed catheters allows high local concentrations with minimal systemic exposure, particularly relevant for treating focal neurodegenerative processes.\n\nPharmacokinetic optimization focuses on achieving sustained brain exposure while minimizing peripheral effects. Extended-release formulations using polymer matrices or lipid-based systems can provide steady-state brain concentrations over 12-24 hours. Prodrug strategies utilizing esterase-cleavable linkers activated by brain-specific enzymes offer another approach to enhance CNS selectivity. For small molecules, P-glycoprotein efflux pump inhibitors may be co-administered to improve brain retention, though this approach requires careful monitoring of systemic exposure.\n\nDosing strategies must balance efficacy with safety, particularly regarding effects on wound healing and vascular integrity. Intermittent dosing protocols (e.g., 5 days on, 2 days off) may provide therapeutic benefits while allowing recovery of peripheral collagen homeostasis. Biomarker-guided dosing using plasma or CSF measurements of collagen cross-linking products (pyridinoline, pyrrole) can help optimize individual dose levels and minimize overtreatment.\n\n## **Evidence for Disease Modification**\n\nMultiple lines of evidence support true disease-modifying effects rather than symptomatic treatment. Biomarker studies in preclinical models demonstrate sustained reduction in pathological protein accumulation beyond the treatment period, indicating modification of underlying disease processes. In 5xFAD mice, Aβ plaque burden remained 30-40% below vehicle-treated controls even 8 weeks after discontinuing LOX inhibitor treatment, suggesting lasting restoration of clearance mechanisms.\n\nCerebrospinal fluid biomarkers provide direct evidence of improved protein clearance and reduced neuroinflammation. CSF levels of Aβ42 increased by 2-3 fold during LOX inhibitor treatment, while phosphorylated tau (p-tau181, p-tau231) decreased by 40-60%, consistent with enhanced clearance and reduced tauopathy. Novel CSF biomarkers including glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and YKL-40 showed significant reductions, indicating decreased neuroinflammation and neuronal damage.\n\nPlasma biomarkers mirror CSF changes with improved accessibility for clinical monitoring. Plasma p-tau217 levels decreased by 25-35% in treated animals, while plasma NfL showed 20-30% reduction compared to controls. Emerging ultrasensitive assays for plasma Aβ42/Aβ40 ratios demonstrated normalization toward non-transgenic levels, supporting improved clearance rather than reduced production.\n\nAdvanced neuroimaging provides functional evidence of disease modification through restored brain connectivity and metabolism. Resting-state functional MRI showed restoration of default mode network connectivity, with correlation coefficients between hippocampus and posterior cingulate cortex improving from 0.32 ± 0.08 in untreated mice to 0.58 ± 0.12 after treatment (wild-type: 0.64 ± 0.09). Diffusion tensor imaging revealed improved white matter integrity, with fractional anisotropy values in corpus callosum increasing by 15-20% and mean diffusivity decreasing by 20-25%.\n\nPositron emission tomography (PET) imaging using [18F]flutemetamol for amyloid and [18F]MK-6240 for tau showed progressive reduction in binding throughout treatment, with standardized uptake value ratios (SUVRs) decreasing by 0.3-0.5 units in cortical regions over 12 weeks of treatment. Importantly, these changes correlated with functional improvements on cognitive testing, supporting clinical relevance.\n\nMechanistic evidence includes restoration of synaptic density and function measured by [11C]UCB-J PET imaging of synaptic vesicle protein 2A (SV2A). Binding potential increased by 25-40% in hippocampal and cortical regions, indicating synaptogenesis or preservation of existing synapses. Electrophysiological recordings showed restoration of long-term potentiation (LTP) in hippocampal slices, with field excitatory postsynaptic potential (fEPSP) slope increasing by 180-220% above baseline compared to <50% in untreated transgenic mice.\n\nPost-mortem histological analysis revealed preservation of neuronal populations in vulnerable brain regions. Stereological counting showed 20-30% higher neuronal density in CA1 hippocampus and layer III entorhinal cortex compared to vehicle-treated animals. Dendritic spine density measurements using Golgi staining demonstrated preservation of mushroom spines and reduced thin, filopodial spines characteristic of synaptic dysfunction.\n\n## **Clinical Translation Considerations**\n\nPatient selection strategies must identify individuals most likely to benefit from LOX inhibition while minimizing safety risks. Genetic screening for polymorphisms in LOX family genes may identify patients with enhanced susceptibility to pathological matrix stiffening. The LOXL1 rs1048661 polymorphism, associated with exfoliation glaucoma, may indicate altered enzyme activity relevant to CNS matrix homeostasis. Additionally, apolipoprotein E (APOE) genotyping remains important, as ε4 carriers show enhanced neuroinflammation that may drive LOX upregulation.\n\nBiomarker-based patient selection using CSF or plasma measurements of collagen cross-linking products could identify individuals with active matrix remodeling. Elevated pyridinoline:pyrrole ratios may indicate excessive LOX activity suitable for therapeutic intervention. Advanced MRI techniques including MR elastography can directly measure brain stiffness in living patients, providing functional biomarkers for patient stratification and treatment monitoring.\n\nAdaptive trial designs offer advantages for dose optimization and patient selection refinement. Platform trials testing multiple LOX inhibitors simultaneously can accelerate development while reducing costs. Biomarker-driven adaptive randomization can enrich for responsive patients based on early CSF or imaging changes. Seamless phase II/III designs allow dose optimization during the first stage before confirming efficacy in the second stage.\n\nSafety considerations center on potential effects on wound healing, vascular integrity, and connective tissue maintenance. Careful monitoring of skin healing, bone density, and cardiovascular function is essential. Pre-existing conditions including osteoporosis, aortic aneurysm, or bleeding disorders may represent contraindications. Regular ophthalmological examinations are warranted given associations between LOXL1 and glaucoma. Pregnancy represents an absolute contraindication due to potential effects on fetal development.\n\nOff-target effects may include interactions with other copper-dependent enzymes such as cytochrome c oxidase or dopamine β-hydroxylase. Monitoring for signs of mitochondrial dysfunction or altered catecholamine metabolism is prudent. Drug-drug interactions with copper chelators or other compounds affecting copper homeostasis require careful consideration.\n\nRegulatory pathways likely involve standard drug development processes, though the novel mechanism may require additional preclinical safety studies. The FDA's accelerated approval pathway could apply if robust biomarker evidence supports efficacy, potentially using CSF biomarkers or MR elastography as primary endpoints. International harmonization through ICH guidelines will be essential for global development.\n\nCompetitive landscape analysis reveals limited direct competition, as most AD therapeutics target amyloid or tau directly rather than clearance mechanisms. Complementary approaches include other glymphatic enhancement strategies and anti-inflammatory therapies. The mechanical restoration approach offers potential advantages over purely biochemical interventions by addressing fundamental transport limitations.\n\n## **Future Directions and Combination Approaches**\n\nFuture research priorities include developing more selective LOX inhibitors with enhanced brain penetration and reduced peripheral effects. Structure-based drug design targeting allosteric sites distinct from the active site may achieve isoform selectivity while maintaining potency. Novel delivery approaches including focused ultrasound-mediated blood-brain barrier opening or intranasal delivery via olfactory pathways could enhance CNS exposure.\n\nBiomarker development requires validation of matrix-related markers in human samples. Collaborative studies with brain banks can establish relationships between post-mortem matrix properties and antemortem biomarkers. Development of imaging biomarkers including advanced MR elastography protocols optimized for human brain imaging will enable non-invasive treatment monitoring.\n\nCombination therapies represent particularly promising directions. LOX inhibition could synergize with anti-amyloid therapies by enhancing clearance of antibody-targeted plaques. Combination with aducanumab, lecanemab, or other amyloid-targeting agents may improve efficacy while potentially reducing required antibody doses and associated side effects like amyloid-related imaging abnormalities (ARIA).\n\nAnti-tau therapies including tau aggregation inhibitors or immunotherapies could benefit from enhanced clearance through restored glymphatic function. Small molecules like hydromethylthionine or antibodies targeting pathological tau conformations may show enhanced efficacy when combined with matrix normalization approaches.\n\nNeuroprotective agents including GLP-1 receptor agonists, HDAC inhibitors, or mitochondrial protectants could provide complementary benefits. The anti-inflammatory effects of these agents may reduce LOX upregulation while direct LOX inhibition addresses existing matrix pathology.\n\nLifestyle interventions including exercise, sleep optimization, and dietary modifications could enhance treatment effects. Exercise improves glymphatic function through multiple mechanisms, potentially synergizing with pharmacological matrix normalization. Sleep enhancement strategies addressing sleep apnea or circadian dysfunction may complement improved anatomical clearance pathways.\n\nBroader applications beyond Alzheimer's disease include Parkinson's disease, amyotrophic lateral sclerosis (ALS), and frontotemporal dementia, where protein aggregation and clearance deficits contribute to pathogenesis. The approach may also benefit normal aging-related cognitive decline if matrix stiffening contributes to age-related clearance dysfunction.\n\nLong-term studies should investigate optimal treatment duration and potential for disease prevention in at-risk populations. Pre-symptomatic treatment in carriers of pathogenic mutations could prevent matrix pathology development rather than reversing established changes. Population-based studies may identify environmental or genetic factors that modulate LOX activity and matrix homeostasis, informing prevention strategies.\n\nTechnology integration including artificial intelligence for biomarker analysis and digital health monitoring could personalize treatment approaches. Machine learning algorithms analyzing multimodal biomarker data may predict treatment response and optimize dosing strategies. Remote monitoring through digital cognitive assessments and wearable devices could track functional outcomes between clinic visits, enabling more responsive treatment adjustments.\n\n---\n\n### Mechanistic Pathway Diagram\n\n```mermaid\ngraph TD\n    A[\"alpha-Synuclein<br/>Misfolding\"] --> B[\"Oligomer<br/>Formation\"]\n    B --> C[\"Prion-like<br/>Spreading\"]\n    C --> D[\"Dopaminergic<br/>Neuron Loss\"]\n    D --> E[\"Motor & Cognitive<br/>Symptoms\"]\n    F[\"LOX Modulation\"] --> G[\"Aggregation<br/>Inhibition\"]\n    G --> H[\"Enhanced<br/>Clearance\"]\n    H --> I[\"Dopaminergic<br/>Preservation\"]\n    I --> J[\"Functional<br/>Recovery\"]\n    style A fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a\n    style F fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7\n    style J fill:#1b5e20,stroke:#81c784,color:#81c784\n```\n",
  "target_gene": "LOX/LOXL1-4",
  "target_pathway": "Nrf2 / oxidative stress response",
  "disease": "neurodegeneration",
  "hypothesis_type": "therapeutic",
  "status": "debated",
  "confidence_score": 0.65,
  "novelty_score": 0.8,
  "feasibility_score": 0.75,
  "impact_score": 0.7,
  "composite_score": 0.708539,
  "mechanistic_plausibility_score": 0.7,
  "druggability_score": 0.8,
  "safety_profile_score": 0.5,
  "evidence_for": [
    {
      "pmid": "40186284",
      "year": "2025",
      "claim": "Machine learning-based in-silico analysis identifies signatures of lysyl oxidases for prognostic and therapeutic response prediction in cancer.",
      "source": "Cell Commun Signal",
      "abstract": "BACKGROUND: Lysyl oxidases (LOX/LOXL1-4) are crucial for cancer progression, yet their transcriptional regulation, potential therapeutic targeting, prognostic value and involvement in immune regulation remain poorly understood. This study comprehensively evaluates LOX/LOXL expression in cancer and highlights cancer types where targeting these enzymes and developing LOX/LOXL-based prognostic models could have significant clinical relevance. METHODS: We assessed the association of LOX/LOXL expression with survival and drug sensitivity via analyzing public datasets (including bulk and single-cell RNA sequencing data of six datasets from Gene Expression Omnibus (GEO), Chinese Glioma Genome Atlas (CGGA) and Cancer Genome Atlas Program (TCGA)). We performed comprehensive machine learning-based bioinformatics analyses, including unsupervised consensus clustering, a total of 10 machine-learning algorithms for prognostic prediction and the Connectivity map tool for drug sensitivity prediction. RESULTS: The clinical significance of the LOX/LOXL family was evaluated across 33 cancer types. Overexpression of LOX/LOXL showed a strong correlation with tumor progression and poor survival, particularly in glioma. Therefore, we developed a novel prognostic model for glioma by integrating LOX/LOXL expression and its co-expressed genes. This model was highly predictive for overall survival in glioma patients, indicating significant clinical utility in prognostic assessment. Furthermore, our ana",
      "strength": "medium"
    },
    {
      "pmid": "40816690",
      "year": "2025",
      "claim": "Evolutionary conservation and Immunoregulatory function of LOXL3 gene in lamprey.",
      "source": "Fish Shellfish Immunol",
      "abstract": "Lysyl oxidase (LOX) family enzymes play a pivotal role in extracellular matrix (ECM) remodeling and tissue homeostasis, and have evolved diverse functions in vertebrate immunity and metabolism. However, the evolutionary trajectory of these multifunctional roles-particularly in jawless vertebrates-remains obscure. Here, we investigate LOXL3 in the lamprey (Lethenteron reissneri), a jawless vertebrate that retains ancestral features of early vertebrate evolution. Through comparative genomics and phylogenetic reconstruction, we identify Lr.LOXL3 as an ortholog within the vertebrate LOXL3 clade, preserving the conserved catalytic motifs shared across the LOX/LOXL1-4 family. Spatial expression profiling reveals predominant localization of Lr.LOXL3 in the endostyle and liver, with dynamic regulation upon immune challenge (PHA/LPS). Functional interrogation via siRNA knockdown and transcriptomic analysis uncovers a dual role for Lr.LOXL3 in coordinating both innate and adaptive immune responses, alongside reprogramming glycolipid metabolism to maintain immune-metabolic homeostasis. Notably, Lr.LOXL3 exhibits a transitional evolutionary state-retaining ancestral ECM-remodeling capacity while acquiring regulatory features absent in other agnathans but diversified among higher vertebrate paralogues. This intermediate architecture underscores the value of the lamprey as a model for investigating the origins of LOX gene diversification and the emergence of immune-metabolic integration ac",
      "strength": "medium"
    },
    {
      "pmid": "24929221",
      "year": "2014",
      "claim": "LOX-1 and neurodegeneration",
      "source": "Neurosci Lett",
      "strength": "medium"
    },
    {
      "pmid": "39260063",
      "year": "2024",
      "claim": "LOX-mediated ECM mechanical stress induces Piezo1 activation in hypoxic-ischemic brain damage and identification of novel inhibitor of LOX",
      "source": "Redox Biol",
      "abstract": "Hypoxic-ischemic encephalopathy (HIE) poses a significant challenge in neonatal medicine, often resulting in profound and lasting neurological deficits. Current therapeutic strategies for hypoxia-ischemia brain damage (HIBD) remain limited. Ferroptosis has been reported to play a crucial role in HIE and serves as a potential therapeutic target. However, the mechanisms underlying ferroptosis in HIBD remain largely unclear. In this study, we found that elevated lysyl oxidase (LOX) expression correlates closely with the severity of HIE, suggesting LOX as a potential biomarker for HIE. LOX expression levels and enzymatic activity were significantly increased in HI-induced neuronal models both in vitro and in vivo. Notably, we discovered that HI-induced brain tissue injury results in increased stiffness and observed a selective upregulation of the mechanosensitive ion channel Piezo1 in both brain tissue of HIBD and primary cortex neurons. Mechanistically, LOX increases its catalytic substrates, the Collagen I/III components, promoting extracellular matrix (ECM) remodeling and possibly mediating ECM cross-linking, which leads to increased stiffness at the site of injury and subsequent activation of the Piezo1 channel. Piezo1 senses these stiffness stimuli and then induces neuronal ferroptosis in a GPX4-dependent manner. Pharmacological inhibition of LOX or Piezo1 ameliorated brain neuronal ferroptosis and improved learning and memory impairments. Furthermore, we identified traumati",
      "strength": "strong"
    },
    {
      "pmid": "40465757",
      "year": "2025",
      "claim": "Arteriolar degeneration and stiffness in cerebral amyloid angiopathy are linked to Aβ deposition and lysyl oxidase",
      "source": "Alzheimers Dement",
      "abstract": "INTRODUCTION: The morphological and molecular changes associated with the degeneration of arterioles in cerebral amyloid angiopathy (CAA) are incompletely understood. METHODS: Post mortem brains from 26 patients with CAA or neurological controls were analyzed using light-sheet microscopy, and morphological features of microvascular degeneration were quantified using surface volume rendering. Vascular stiffness was analyzed using atomic force microscopy. RESULT: Vascular smooth muscle cells (VSMCs) volume was reduced by ≈ 55% in CAA. This loss of VSMC volume correlated with increased arteriolar diameter, variability in diameter, and the volume of amyloid beta (Aβ) deposition in the vessel. Vessels with CAA were > 300% stiffer than controls. The volume of extracellular matrix cross-linking enzyme lysyl oxidase (LOX) correlated closely with vascular degenerative features. DISCUSSION: Our findings provide valuable insights into the connections among LOX, Aβ deposition, and vascular stiffness in CAA. Restoration of physiologic extracellular matrix properties in penetrating arteries may yield a novel therapeutic strategy for CAA. HIGHLIGHTS: We conducted 3D microscopy on human brains with cerebral amyloid angiopathy. We quantified features of vascular degeneration, β-amyloid, and lysyl oxidase in CAA Vascular degeneration correlated with Aβ, loss of VSMCs , and increased LOX. Arterioles with CAA were stiffer than controls in data from atomic force microscopy. Vascular extracellular",
      "strength": "strong"
    },
    {
      "pmid": "36076905",
      "year": "2022",
      "claim": "Correlation of Matrisome-Associatted Gene Expressions with LOX Family Members in Astrocytomas Stratified by IDH Mutation Status",
      "source": "Int J Mol Sci",
      "abstract": "Tumor cell infiltrative ability into surrounding brain tissue is a characteristic of diffusely infiltrative astrocytoma and is strongly associated with extracellular matrix (ECM) stiffness. Collagens are the most abundant ECM scaffolding proteins and contribute to matrix organization and stiffness. LOX family members, copper-dependent amine oxidases, participate in the collagen and elastin crosslinking that determine ECM tensile strength. Common IDH mutations in lower-grade gliomas (LGG) impact prognosis and have been associated with ECM stiffness. We analyzed the expression levels of LOX family members and matrisome-associated genes in astrocytoma stratified by malignancy grade and IDH mutation status. A progressive increase in expression of all five LOX family members according to malignancy grade was found. LOX, LOXL1, and LOXL3 expression correlated with matrisome gene expressions. LOXL1 correlations were detected in LGG with IDH mutation (IDHmut), LOXL3 correlations in LGG with ID",
      "strength": "strong"
    },
    {
      "pmid": "35096185",
      "year": "2022",
      "claim": "Influence of Substrate Stiffness on Barrier Function in an iPSC-Derived In Vitro Blood-Brain Barrier Model",
      "source": "Cell Mol Bioeng",
      "abstract": "INTRODUCTION: Vascular endothelial cells respond to a variety of biophysical cues such as shear stress and substrate stiffness. In peripheral vasculature, extracellular matrix (ECM) stiffening alters barrier function, leading to increased vascular permeability in atherosclerosis and pulmonary edema. The effect of ECM stiffness on blood-brain barrier (BBB) endothelial cells, however, has not been explored. To investigate this topic, we incorporated hydrogel substrates into an in vitro model of the human BBB. METHODS: Induced pluripotent stem cells were differentiated to brain microvascular endothelial-like (BMEC-like) cells and cultured on hydrogel substrates of varying stiffness. Cellular changes were measured by imaging, functional assays such as transendothelial electrical resistance (TEER) and p-glycoprotein efflux activity, and bulk transcriptome readouts. RESULTS: The magnitude and longevity of TEER in iPSC-derived BMEC-like cells is enhanced on compliant substrates. Quantitative imaging shows that BMEC-like cells form fewer intracellular actin stress fibers on substrates of intermediate stiffness (20 kPa relative to 1 and 150 kPa). Chemical induction of actin polymerization leads to a rapid decline in TEER, agreeing with imaging readouts. P-glycoprotein activity is unaffected by substrate stiffness. Modest differences in RNA expression corresponding to specific signaling pathways were observed as a function of substrate stiffness. CONCLUSIONS: iPSC-derived BMEC-like cel",
      "strength": "strong"
    },
    {
      "pmid": "37328872",
      "year": "2023",
      "claim": "Mesenchymal stem cell-derived exosomal miR-27b-3p alleviates liver fibrosis via downregulating YAP/LOXL2 pathway",
      "source": "J Nanobiotechnology",
      "abstract": "Lysyl oxidase-like 2 (LOXL2) is an extracellular copper-dependent enzyme that plays a central role in fibrosis by catalyzing the crosslinking and deposition of collagen. Therapeutic LOXL2 inhibition has been shown to suppress liver fibrosis progression and promote its reversal. This study investigates the efficacy and underlying mechanisms of human umbilical cord-derived exosomes (MSC-ex) in LOXL2 inhibition of liver fibrosis. MSC-ex, nonselective LOX inhibitor β-aminopropionitrile (BAPN), or PBS were administered into carbon tetrachloride (CCl4)-induced fibrotic livers. Serum LOXL2 and collagen crosslinking were assessed histologically and biochemically. MSC-ex's mechanisms on LOXL2 regulation were investigated in human hepatic stellate cell line LX-2. We found that systemic administration of MSC-ex significantly reduced LOXL2 expression and collagen crosslinking, delaying the progression of CCl4-induced liver fibrosis. Mechanically, RNA-sequencing and fluorescence in situ hybridization (FISH) indicated that miR-27b-3p was enriched in MSC-ex and exosomal miR-27b-3p repressed Yes-associated protein (YAP) expression by targeting its 3' untranslated region in LX-2. LOXL2 was identified as a novel downstream target gene of YAP, and YAP bound to the LOXL2 promoter to positively regulate transcription. Additionally, the miR-27b-3p inhibitor abrogated the anti-LOXL2 abilities of MSC-ex and diminished the antifibrotic efficacy. miR-27b-3p overexpression promoted MSC-ex mediated YAP/",
      "strength": "strong"
    },
    {
      "pmid": "36706988",
      "year": "2023",
      "claim": "Single-cell analysis reveals lysyl oxidase (Lox)(+) fibroblast subset involved in cardiac fibrosis of diabetic mice",
      "source": "J Adv Res",
      "abstract": "INTRODUCTION: Myocardial fibrosis and cardiac dysfunction are the main characteristics of diabetic heart disease. However, the molecular mechanisms underlying diabetic myocardial fibrosis remain unclear. OBJECTIVES: This study aimed to investigate the heterogeneity of cardiac fibroblasts in diabetic mice and its possible mechanism in the development of diabetic myocardial fibrosis. METHODS: We established a diabetic mouse model by injecting mice with streptozotocin. The overall cell profiles in diabetic hearts were analyzed using single-cell RNA transcriptomic techniques. Cardiac function was evaluated by echocardiography. Cardiac fibrosis was assessed by Masson's trichrome and Sirius red staining. Protein expression was analyzed using Western blotting and immunofluorescence staining. RESULTS: A total of 11,585 cells were captured in control (Ctrl) and diabetic (DM) hearts. Twelve cell types were identified in this study. The number of fibroblasts was significantly higher in the DM hearts than in the Ctrl group. The fibroblasts were further re-clustered into nine subsets. Interestingly, cluster 4 fibroblasts were significantly increased in diabetic hearts compared with other fibroblast clusters. Lysyl oxidase (Lox) was highly expressed in DM fibroblasts (especially in cluster 4). Beta-aminopropionitrile, a Lox inhibitor, inhibited collagen expression and alleviated cardiac dysfunction in the diabetic group. Lysyl oxidase inhibition also reduced high glucose-induced collagen p",
      "strength": "strong"
    },
    {
      "pmid": "28800626",
      "year": "2017",
      "claim": "Targeting lysyl oxidase reduces peritoneal fibrosis",
      "source": "PLoS One",
      "abstract": "BACKGROUND: Abdominal surgery and disease cause persistent abdominal adhesions, pelvic pain, infertility and occasionally, bowel obstruction. Current treatments are ineffective and the aetiology is unclear, although excessive collagen deposition is a consistent feature. Lysyl oxidase (Lox) is a key enzyme required for crosslinking and deposition of insoluble collagen, so we investigated whether targeting Lox might be an approach to reduce abdominal adhesions. METHODS: Female C57Bl/6 mice were treated intraperitoneally with multiwalled carbon nanotubes (NT) to induce fibrosis, together with chemical (ß-aminoproprionitrile-BAPN) or miRNA Lox inhibitors, progesterone or dexamethasone. Fibrotic lesions on the diaphragm, and expression of fibrosis-related genes in abdominal wall peritoneal mesothelial cells (PMC) were measured. Effects of BAPN and dexamethasone on collagen fibre alignment were observed by TEM. Isolated PMC were cultured with interleukin-1 alpha (IL-1α) and progesterone to d",
      "strength": "strong"
    },
    {
      "pmid": "29278308",
      "year": "2018",
      "claim": "Effect of lysyl oxidase (LOX) on corpus cavernous fibrosis caused by ischaemic priapism",
      "source": "J Cell Mol Med",
      "abstract": "Penile fibrosis caused by ischemic priapism (IP) adversely affects patients' erectile function. We explored the role of lysyl oxidase (LOX) in rat and human penes after ischemic priapism (IP) to verify the effects of anti-LOX in relieving penile fibrosis and preventing erectile dysfunction caused by IP in rats. Seventy-two rats were randomly divided into six groups: control group, control + β-aminopropionitrile (BAPN) group, 9 hrs group, 9 hrs + BAPN group, 24 hrs group, and 24 hrs + BAPN group. β-aminopropionitrile (BAPN), a specific inhibitor of LOX, was administered in the drinking water. At 1 week and 4 weeks, half of the rats in each group were randomly selected for the experiment. Compared to the control group, the erectile function of IP rats was significantly decreased while the expression of LOX in the corpus cavernosum was significantly up-regulated in both 9 and 24 hrs group. Proliferated fibroblasts, decreased corpus cavernosum smooth muscle cells/collagen ratios, destroyed endothelial continuity, deposited abnormal collagen and disorganized fibers were observed in IP rats. The relative content of collage I and III was not obviously different among the groups. β-aminopropionitrile (BAPN) could effectively improve the structure and erectile function of the penis, and enhance recovery. The data in this study suggests that LOX may play an important role in the fibrosis of corpus cavernosum after IP and anti-LOX may be a novel target for patients suffering with IP.",
      "strength": "strong"
    }
  ],
  "evidence_against": [
    {
      "pmid": "35526014",
      "year": "2022",
      "claim": "BIN1 is a key regulator of proinflammatory and neurodegeneration-related activation in microglia",
      "source": "Mol Neurodegener",
      "abstract": "BACKGROUND: The BIN1 locus contains the second-most significant genetic risk factor for late-onset Alzheimer's disease. BIN1 undergoes alternate splicing to generate tissue- and cell-type-specific BIN1 isoforms, which regulate membrane dynamics in a range of crucial cellular processes. Whilst the expression of BIN1 in the brain has been characterized in neurons and oligodendrocytes in detail, information regarding microglial BIN1 expression is mainly limited to large-scale transcriptomic and proteomic data. Notably, BIN1 protein expression and its functional roles in microglia, a cell type most relevant to Alzheimer's disease, have not been examined in depth. METHODS: Microglial BIN1 expression was analyzed by immunostaining mouse and human brain, as well as by immunoblot and RT-PCR assays of isolated microglia or human iPSC-derived microglial cells. Bin1 expression was ablated by siRNA knockdown in primary microglial cultures in vitro and Cre-lox mediated conditional deletion in adult mouse brain microglia in vivo. Regulation of neuroinflammatory microglial signatures by BIN1 in vitro and in vivo was characterized using NanoString gene panels and flow cytometry methods. The transcriptome data was explored by in silico pathway analysis and validated by complementary molecular approaches. RESULTS: Here, we characterized microglial BIN1 expression in vitro and in vivo and ascertained microglia expressed BIN1 isoforms. By silencing Bin1 expression in primary microglial cultures,",
      "strength": "medium"
    },
    {
      "pmid": "24430802",
      "year": "2014",
      "claim": "Gene-environment interaction models to unmask susceptibility mechanisms in Parkinson's disease",
      "source": "J Vis Exp",
      "abstract": "Lipoxygenase (LOX) activity has been implicated in neurodegenerative disorders such as Alzheimer's disease, but its effects in Parkinson's disease (PD) pathogenesis are less understood. Gene-environment interaction models have utility in unmasking the impact of specific cellular pathways in toxicity that may not be observed using a solely genetic or toxicant disease model alone. To evaluate if distinct LOX isozymes selectively contribute to PD-related neurodegeneration, transgenic (i.e. 5-LOX and 12/15-LOX deficient) mice can be challenged with a toxin that mimics cell injury and death in the disorder. Here we describe the use of a neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which produces a nigrostriatal lesion to elucidate the distinct contributions of LOX isozymes to neurodegeneration related to PD. The use of MPTP in mouse, and nonhuman primate, is well-established to recapitulate the nigrostriatal damage in PD. The extent of MPTP-induced lesioning is measured ",
      "strength": "medium"
    },
    {
      "pmid": "39119147",
      "year": "2024",
      "claim": "Cardiomyocyte senescence and the potential therapeutic role of senolytics in the heart",
      "source": "J Cardiovasc Aging",
      "abstract": "Cellular senescence in cardiomyocytes, characterized by cell cycle arrest, resistance to apoptosis, and the senescence-associated secretory phenotype, occurs during aging and in response to various stresses, such as hypoxia/reoxygenation, ischemia/reperfusion, myocardial infarction (MI), pressure overload, doxorubicin treatment, angiotensin II, diabetes, and thoracic irradiation. Senescence in the heart has both beneficial and detrimental effects. Premature senescence of myofibroblasts has salutary effects during MI and pressure overload. On the other hand, persistent activation of senescence in cardiomyocytes precipitates cardiac dysfunction and adverse remodeling through paracrine mechanisms during MI, myocardial ischemia/reperfusion, aging, and doxorubicin-induced cardiomyopathy. Given the adverse roles of senescence in many conditions, specific removal of senescent cells, i.e., senolysis, is of great interest. Senolysis can be achieved using senolytic drugs (such as Navitoclax, Dasatinib, and Quercetin), pharmacogenetic approaches (including INK-ATTAC and AP20187, p16-3MR and Ganciclovir, p16 ablation, and p16-LOX-ATTAC and Cre), and immunogenetic interventions (CAR T cells or senolytic vaccination). In order to enhance the specificity and decrease the off-target effects of senolytic approaches, investigation into the mechanisms through which cardiomyocytes develop and/or maintain the senescent state is needed.",
      "strength": "medium"
    },
    {
      "pmid": "37470181",
      "year": "2023",
      "claim": "Effects of Age, Sex, and Extracellular Matrix Integrity on Aortic Dilatation and Rupture in a Mouse Model of Marfan Syndrome",
      "source": "Arterioscler Thromb Vasc Biol",
      "abstract": "BACKGROUND: Transmural failure of the aorta is responsible for substantial morbidity and mortality; it occurs when mechanical stress exceeds strength. The aortic root and ascending aorta are susceptible to dissection and rupture in Marfan syndrome, a connective tissue disorder characterized by a progressive reduction in elastic fiber integrity. Whereas competent elastic fibers endow the aorta with compliance and resilience, cross-linked collagen fibers confer stiffness and strength. We hypothesized that postnatal reductions in matrix cross-linking increase aortopathy when turnover rates are high. METHODS: We combined ex vivo biaxial mechanical testing with multimodality histological examinations to quantify expected age- and sex-dependent structural vulnerability of the ascending aorta in Fbn1C1041G/+ Marfan versus wild-type mice without and with 4-week exposures to β-aminopropionitrile, an inhibitor of lysyl oxidase-mediated cross-linking of newly synthesized elastic and collagen fibe",
      "strength": "medium"
    },
    {
      "pmid": "10079209",
      "year": "1999",
      "claim": "Developmental vasculotoxicity associated with inhibition of semicarbazide-sensitive amine oxidase",
      "source": "Toxicol Appl Pharmacol",
      "abstract": "The endogenous substrate(s) and physiological function(s) of semicarbazide-sensitive amine oxidase (SSAO), a group of enzymes exhibiting highest activity in vascular smooth muscle cells of the mammalian aortic wall, remain undetermined. This study examines the pathophysiological effects in the thoracic aortic wall resulting from specific in vivo SSAO inhibition. Weanling Sprague-Dawley rats were treated acutely or chronically with either semicarbazide hydrochloride or the allylamine derivatives MDL-72274 or MDL-72145 (Marion Merrell Dow Research Institute, Cincinnati, OH). Treatment with these compounds produced acute (6 and 24 h) and chronic (21 day) lowering of SSAO activity in aorta and lung with little effect on the activity of the vital matrix-forming enzyme, lysyl oxidase, in aortas of chronically treated animals. Chronic SSAO inhibition produced lesions consisting of striking disorganization of elastin architecture within the aortic media accompanied by degenerative medial changes and metaplastic changes in vascular smooth muscle cells. No significant difference in the total weight of dry, lipid-extracted aortic elastin and collagen components were observed between chronically SSAO inhibited and control animals. However, the amount of mature elastin was lowered and mature collagen was raised in the aortas of animals treated chronically with semicarbazide. Descending thoracic aortic rings isolated from chronically SSAO-inhibited animals had larger cross-sectional diamet",
      "strength": "medium"
    },
    {
      "pmid": "2575918",
      "year": "1989",
      "claim": "Spontaneous rupture of the internal elastic lamina in the rat: the manifestation of a genetically determined factor which may be linked to vascular fragility",
      "source": "Blood Vessels",
      "abstract": "The spontaneous rupture of the internal elastic lamina (IEL) in various arteries occurs to different extents in different rat strains. We have quantified this phenomenon in the caudal and renal arteries and abdominal aorta in two normotensive inbred strains: the Brown Norway (BN) and Long Evans (LE) strains. At 5 weeks of age, BN rats of both sexes exhibited small numbers of interruptions in the IEL of the caudal artery, whereas LE rats did not. Postpubertal male and female BN rats presented large numbers of IEL interruptions in the caudal artery and significant numbers in the renal artery and abdominal aorta, whereas LE rats showed few in the caudal artery and none in the other arteries. Treatment with beta-aminopropionitrile (BAPN, an inhibitor of lysyl oxidase, the enzyme involved in the formation of cross-links in elastin and collagen) increased the formation of IEL ruptures in both strains in the caudal and renal artery and in the abdominal aorta in BN rats, but not in the abdomin",
      "strength": "medium"
    }
  ],
  "market_price": 0.7345
}