Circular RNAs (circRNAs) are covalently closed, single-stranded RNAs generated via backsplicing. They are highly stable and evolutionarily conserved, making them promising candidates for cancer therapy and diagnosis. CircRNAs regulate cancer progression by modulating genome instability, angiogenesis, metastasis, stemness, and chemoresistance. They do so through mechanisms including microRNA (miRNA) sponging, protein interaction, translational templating, and transcription/translation regulation. CircRNAs play a critical role in cancer immunotherapy. They modulate immune checkpoint blockade (ICB) responses and cytokine secretion to reshape the tumor immune microenvironment (TME). CircRNAs also serve as stable platforms for neoantigen-based cancer vaccines and improve in vivo chimeric antigen receptor T cell (CAR-T) therapy by replacing unstable linear mRNA. Additionally, circRNAs are potential noninvasive biomarkers due to their abundance in body fluids and differential tumor-normal expression. Despite challenges such as unclear regulatory networks, off-target effects, and inefficient delivery, this review systematically summarizes the biogenesis of circRNAs, their functional mechanisms, their roles in cancer progression, and their applications in cancer immunotherapy. The review also highlights their utility as biomarkers and future translational directions, providing a focused overview of their potential to advance cancer immunotherapy.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the most common monogenic form of cerebral small vessel disease (CSVD), is caused by mutations in NOTCH3. However, the effects of NOTCH3 mutations on lipid metabolism remain poorly understood. In this study, plasma samples from CADASIL patients and matched healthy controls were subjected to lipidomic analysis. Stable 293T cell lines expressing an empty vector (NC), wild-type (WT) NOTCH3, or CADASIL-associated NOTCH3 mutants (R110C, R133C, R1175W, and R544C), as well as hCMEC/D3 cell lines expressing NC, WT, or R544C, were established to investigate lipid metabolic alterations. Lipid droplet (LD) accumulation, cholesterol levels, and the expression of cholesterol transport-related molecules were assessed. Lipidomic profiling revealed significant alterations in plasma lipid profiles in CADASIL patients compared with healthy controls. In 293T cells, LD accumulation was significantly increased in the R110C, R1175W, and R544C groups, but not in the R133C group, whereas cholesterol levels were elevated in all mutant groups. In hCMEC/D3 cells, expression of the R544C mutant markedly promoted cholesterol accumulation and reduced the expression of the cholesterol transporters ABCA1 and ABCG1. These findings indicate that NOTCH3 mutations are associated with disrupted cellular lipid homeostasis and suggest that lipid metabolic dysregulation may represent a potential mechanism contributing to CADASIL pathogenesis.

BackgroundCerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is caused by mutations in the NOTCH3 gene. Previous research has predominantly focused on vascular smooth muscle cell pathology, whereas the role of brain microvascular endothelial cells (BMECs) in the disease remains unclear.ObjectiveTo investigate the impact of the NOTCH3-R544C mutation on BMECs function and to elucidate the underlying mechanisms of endothelial dysfunction in CADASIL.MethodsUsing CADASIL transgenic mice and endothelial cell (EC) models stably expressing NOTCH3-R544C, the impact of the mutation on endothelial function was assessed through immunofluorescence staining, RNA-seq analysis, protein-protein interaction (PPI) network mapping, and lipid and cellular function assays.ResultsSignificant NOTCH3 extracellular domain (NOTCH3ECD) deposition and reduced microvascular density are observed in CADASIL mice. R544C mutant cells exhibit abnormal NOTCH3ECD accumulation alongside pronounced gene expression dysregulation, predominantly enriched in pathways related to inflammation, cell migration. The PPI network centers on CXCL10 as a pivotal hub, forming a core "inflammation-migration" pathological axis. R544C cells exhibit heightened inflammatory responses, cholesterol accumulation, reduced cell viability, and increased sensitivity to inflammatory stimuli.ConclusionsThe NOTCH3-R544C mutation disrupts inflammatory regulation, migratory capacity, and lipid metabolic homeostasis in BMECs, leading to endothelial dysfunction and revealing a key mechanism of endothelial injury in CADASIL.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic cerebral small-vessel disease caused by NOTCH3 mutations, yet its pathogenic mechanisms remain incompletely understood due to limited disease models. The NOTCH3 R544C mutation is a prevalent hotspot in East Asian populations, but patient-derived iPSC models are lacking. Here, we generated an iPSC line from peripheral blood mononuclear cells of a middle-aged CADASIL patient carrying a heterozygous NOTCH3 c.1630C > T (p.Arg544Cys, R544C) mutation using a Sendai virus (SeV)-based reprogramming approach. The iPSCs exhibited typical morphology, normal 46, XY karyotype, expressed pluripotency markers (OCT4, NANOG, TRA-1–60, SSEA-4), and cleared SeV vectors after passaging. They differentiated into derivatives of all three germ layers, and STR analysis confirmed donor identity. Functionally, CADASIL iPSCs showed abnormal accumulation of the NOTCH3 extracellular domain (NOTCH3ECD) with unchanged NOTCH3 full-length and intracellular domain levels, and upregulation of canonical downstream genes HEY1, NRARP, and HES1, indicating activation of the NOTCH3 signaling pathway. This study establishes and characterizes a NOTCH3 R544C patient-derived iPSC line, providing a valuable model for investigating CADASIL pathogenesis and potential therapeutic strategies, with novel insights into early NOTCH3ECD accumulation and pathway activation.

Chronic cerebral hypoperfusion (CCH) is a key pathological hallmark observable in multiple subtypes of cerebral small vessel disease (CSVD). This condition causes both structural and functional changes within the brain’s vascular system, and is particularly damaging to brain microvascular endothelial cells (BMECs). The exact molecular mechanisms underlying BMEC impairment in CCH remain insufficiently defined despite their clinical importance. Emerging evidence indicates that disturbances in intracellular lipid metabolism might contribute substantially to promoting endothelial inflammation and functional deficits. This study aims to investigate whether aberrant lipid metabolism contributes to endothelial inflammation and tight junction (TJ) dysfunction in BMECs under the condition of CCH, and to assess the therapeutic potential of intervention with simvastatin. A rat model of chronic CSVD was created via permanent bilateral ligation of the common carotid arteries (2VO) in animal subjects. Samples of cortical microvasculature were collected at predefined intervals for transcriptome profiling. Assessments of lipid metabolism, inflammation-related factors, and TJ protein levels were conducted in both in vivo and after induction of hypoxia and administration of simvastatin. At 14d post-2VO, mRNA expression of TJ proteins including occludin (Ocln), claudin-5 (Cldn5), and zonula occludens-1 (Zo-1) was significantly downregulated in BMECs compared to sham controls. Simultaneously, there was a notable buildup of lipid droplets, rise in cholesterol levels, and upregulation of pro-inflammatory indicators including VCAM1, TNF-α, and ICAM1. Simvastatin administration effectively reduced lipid buildup, suppressed inflammation, and restored TJ integrity. Dysregulated lipid metabolism and heightened inflammatory responses contribute to TJ disruption in BMECs with CCH. Simvastatin therapy mitigates lipid accumulation, dampens inflammation, and improves TJ function in BMECs with CCH.

Background DNase2a, a key enzyme responsible for clearing cytoplasmic double-stranded DNA, prevents cytosolic DNA accumulation. Accumulating evidence suggests that aberrant cytosolic DNA accumulation contributes to Parkinson’s disease (PD) pathogenesis, yet the role of DNase2a in PD remains unclear. Methods We examined the effects of neuronal DNase2a and cytosolic damaged DNA on α-synuclein (α-Syn) accumulation in cultured neurons and male A53T transgenic mice, and investigated the underlying mechanism by which α-Syn modulates DNase2a expression. Results The levels of DNase2a were markedly reduced in the brain of A53T α-Syn transgenic mice, accompanied by increased cytoplasmic DNA accumulation. Decreased neuronal DNase2a led to persistent cytosolic DNA accumulation and suppressed NEDD4-mediated α-Syn ubiquitination and degradation, exacerbating α-Syn accumulation and PD pathology in vitro and in vivo. Moreover, A53T α-Syn further aggravated cytosolic DNA accumulation and then repressed MEF2C-mediated DNase2a transcription via activating the cGAS-STING-IFN pathway, forming a deleterious loop between DNase2a and α-Syn. Consistently, neuronal DNase2a deficiency in WT mice drove α-Syn pathology and dopaminergic neuronal degeneration, leading to motor deficits characteristic of PD, while neuronal DNase2a overexpression in A53T transgenic mice significantly ameliorated motor deficits by reducing α-Syn accumulation and preserving dopaminergic neuron integrity. Conclusions Our findings reveal that DNase2a deficiency disrupts α-Syn degradation and accelerates PD pathogenesis, suggesting that DNase2a is a potential therapeutic target for PD.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic cerebral small-vessel disease caused by mutations in NOTCH3 and is the most common hereditary cerebral small-vessel disease in adults. The clinical manifestations of CADASIL include migraines, recurrent ischemic stroke, progressive cognitive deterioration, and psychiatric symptoms. The most prevalent and earliest imaging alterations in CADASIL are white matter hyperintensities in the periventricular white matter, temporal pole, external capsule, frontoparietal white matter, and other areas on magnetic resonance imaging. Despite the substantial variations in the clinical phenotypes and disease severity in patients with CADASIL, the specific mechanisms underlying these differences remain unclear. Exploring these underlying mechanisms is crucial for enhancing our understanding of CADASIL and offering insights into its early diagnosis and treatment. This review explores the advances in research on the molecular mechanisms contributing to the variability in clinical phenotypes and disease severity among CADASIL patients with different mutations.

Background:Myasthenia gravis (MG), an autoimmune disorder characterized by B cell-driven autoantibody production, exhibits heterogeneous B cell subsets dysregulation and incompletely defined signaling mechanisms. Methods:A cohort of 20 naïve MG patients positive for anti-acetylcholine receptor (AChR) antibodies and 15 healthy controls was analyzed. Peripheral blood mononuclear cells underwent proteomic profiling, flow cytometry (age-associated B cells (ABCs), plasma cells, T follicular helper cells, and regulatory B cells), and western blot validation of nuclear factor kappa-B (NF-κB)/cellular reticuloendotheliosis oncogene homolog (c-Rel) expression. Clinical severity was assessed using quantitative MG (QMG) scores. Statistical analyses included differential protein expression, pathway enrichment, and receiver operating characteristic (ROC) curve evaluation. Results:Proteomics revealed significant activation of the B cell receptor and NF-κB/c-Rel signaling pathways in MG patients, validated by upregulated NF-κB/c-Rel expression (p < 0.01). Flow cytometry demonstrated elevated ABCs (CD19+CD11c+T-bet+), plasma cells, and T follicular helper cells, alongside reduced regulatory B cells in MG (p < 0.001). The proportion of ABCs correlated positively with QMG scores (r = 0.5015, p = 0.024) but not with AChR antibody titers, suggesting antibody-independent mechanisms. ROC analysis identified moderate diagnostic utility of ABCs for moderate-to-severe MG (QMG scores ≥ 6; area under the curve = 0.68, 95% confidence intervals: 0.42-0.94). Conclusion:This study establishes ABCs and NF-κB/c-Rel signaling as central contributors to AChR-MG immunopathology. Therefore, ABCs may serve as complementary biomarkers for clinical stratification.

Blood-brain barrier (BBB) dysfunction plays a pivotal role in the pathology of chronic cerebral hypoperfusion (CCH)-related neurodegenerative diseases. Continuous endothelial cells (EC) that line the blood vessels of the brain are important components of the BBB to strictly control the flow of substances and maintain the homeostatic environment of the brain. However, the molecular mechanisms from the perspective of EC-induced BBB dysfunction after CCH are largely unknown. In this study, the BBB function was assessed using immunostaining and transmission electron microscopy. The EC dysfunction profile was screened by using EC enrichment followed by RNA sequencing. After identified the key EC dysfunction factor, C-kit, we used the C-kit inhibition drug (imatinib) and C-kit down-regulation method (AAV-BR1-C-kit shRNA) to verify the role of C-kit on BBB integrity and EC transcytosis after CCH. Furthermore, we also activated C-kit with stem cell factor (SCF) to observe the effects of C-kit on BBB following CCH. We explored that macromolecular proteins entered the brain mainly through EC transcytosis after CCH and caused neuronal loss. Additionally, we identified receptor tyrosine kinase C-kit as a key EC dysfunction molecule. Furthermore, the pharmacological inhibition of C-kit with imatinib counteracted BBB leakage by reducing caveolae-mediated transcytosis. Moreover, treatment with AAV-BR1-C-kit shRNA, which targets brain EC to inhibit C-kit expression, also ameliorated BBB leakage by reducing caveolae-mediated transcytosis. Furthermore, the SCF increased the permeability of the BBB by actively increasing caveolae-mediated transcytosis. This study provides evidence that C-kit is a key BBB permeability regulator through caveolae-mediated transcytosis in EC after CCH.

BackgroundCerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is one of the most common inherited cerebral small vessel diseases caused by the NOTCH3 gene mutation. This mutation leads to the accumulation of NOTCH3 extracellular domain protein (NOTCH3ECD) into the cerebral arterioles, causing recurrent stroke, white matter lesions, and cognitive impairment. With the development of gene sequencing technology, cysteine-sparing mutations can also cause CADASIL disease, however, the pathogenicity and pathogenic mechanisms of cysteine-sparing mutations remain controversial.ObjectiveTo analyze the pathogenicity and pathological features of cysteine-sparing mutations in both in vitro and in vivo mouse models.MethodsA cysteine-sparing mutant of NOTCH3ECD R75Q was constructed by lentiviral transfection in vitro, and the NOTCH3 R75Q knock-in mouse model was constructed by CRISPR/Cas-mediated genome engineering in vivo. A cycloheximide pulse-chase experiment was used to analyze the degradation of NOTCH3 extracellular domain proteins, and the deposition characteristics of NOTCH3ECD were quantitatively analyzed by immunohistochemical staining. The characteristics of the smooth muscle cells and granular osmiophilic materials were observed using electron microscopy.ResultsWe elucidated that the NOTCH3 R75Q mutation is pathogenic. NOTCH3ECD R75Q was found to be resistant to protein degradation and more likely to cause abnormal aggregation of NOTCH3ECD, resulting in reduced cell activity in vitro. The NOTCH3 R75Q mouse model showed pathological characteristics of CADASIL, with age-dependent NOTCH3ECD, granular osmiophilic material, and degenerated smooth muscle cells detected in the brain.ConclusionTo our knowledge, this is the first study to analyze the pathogenicity of NOTCH3 R75Q cysteine-sparing mutations in both in vitro and in vivo models. We demonstrate that NOTCH3ECD induced by NOTCH3 R75Q mutation has toxic effects on cells and reveal the deposition characteristics of NOTCH3ECD in the brain. This provides a feasible model and lays the foundation for further studies on the pathogenesis and therapeutic strategies of NOTCH3 cysteine-sparing mutations.

Background: Cerebral autosomal-dominant arteriopathy with subcortical infarction and leukoencephalopathy (CADASIL) is an inherited small-vessel disease that affects the white matter of the brain. Recent studies have confirmed that the deposition of NOTCH3ECD is the main pathological basis of CADASIL; however, whether different mutations present the same pathological characteristics remains to be further studied. Some studies have found that mitochondrial dysfunction is related to CADASIL; however, the specific effects of NOTCH3ECD on mitochondrial remain to be determined. Objective: We aimed to explore the role of mitochondrial dysfunction in CADASIL. Methods: We established transgenic human embryonic kidney-293T cell models (involving alterations in cysteine and non-cysteine residues) via lentiviral transfection. Mitochondrial function and structure were assessed using flow cytometry and transmission electron microscopy, respectively. Mitophagy was assessed using western blotting and immunofluorescence. Results: We demonstrated that NOTCH3ECD deposition affects mitochondrial morphology and function, and that its protein levels are significantly correlated with mitochondrial quality and can directly bind to mitochondria. Moreover, NOTCH3ECD deposition promoted the induction of autophagy and mitophagy. However, these processes were impaired, leading to abnormal mitochondrial accumulation. Conclusions: This study revealed a common pathological feature of NOTCH3ECD deposition caused by different NOTCH3 mutations and provided new insights into the role of NOTCH3ECD in mitochondrial dysfunction and mitophagy.

Alzheimer’s disease (AD) is an age-related progressive neurodegenerative disease, and approximately 10% of AD cases are early-onset familial AD (EOFAD), which is mainly linked to point mutations in genes encoding presenilins ( PS1 and PS2 ). Mutations in PS2 are extremely rare and have not received enough attention. Recently, studies have found that Rho GTPase activity is closely related to the pathogenesis of AD. In this study, we used transcriptome sequencing in PS2 siRNA-transfected SH-SY5Y cells and found a group of differentially expressed genes (DEGs) related to the regulation of GTPase activity. Among those DEGs, the most significantly downregulated was Rho guanine nucleotide exchange factor 5 ( ARHGEF5 ). GTPase activity in PS2 siRNA-transfected cells was significantly decreased. Then, we found that the expression of ARHGEF5 and the GTPase activity of Mitochondrial Rho GTPase 2 (Miro2) in PS2 D439A mutant SH-SY5Y cells were significantly decreased. We found for the first time that PS2 can bind to Miro2, and the PS2 D439A mutation reduced the binding between PS2 and Miro2, reduced the expression of Miro2, and resulted in an imbalance in mitochondrial fusion/fission dynamics. In conclusion, PS2 gene knockdown may participate in the pathogenesis of AD through the regulation of GTPase activity. The imbalance in mitochondrial dynamics mediated by the PS2 D439A mutation through regulation of the expression and GTPase activity of Miro2 may be a potential pathogenic mechanism of AD.

Introduction: Spinocerebellar ataxias 36 (SCA36) is the neurodegenerative disease caused by the GGCCTG Hexanucleotide repeat expansions in NOP56, which is too long to sequence using short-read sequencing. Single molecule real time (SMRT) sequencing can sequence across disease-causing repeat expansion. We report the first long-read sequencing data across the expansion region in SCA36.Methods: We collected and described the clinical manifestations and imaging features of Han Chinese pedigree with three generations of SCA36. Also, we focused on structural variation analysis for intron 1 of the NOP56 gene by SMRT sequencing in the assembled genome.Results: The main clinical features of this pedigree are late-onset ataxia symptoms, with a presymptomatic presence of affective and sleep disorders. In addition, the results of SMRT sequencing showed the specific repeat expansion region and demonstrated that the region was not composed of single GGCCTG hexanucleotides and there were random interruptions.Discussion: We extended the phenotypic spectrum of SCA36. We applied SMRT sequencing to reveal the correlation between genotype and phenotype of SCA36. Our findings indicated that long-read sequencing is well suited to characterize known repeat expansion.

Background: Chronic cerebral hypoperfusion (CCH) is associated with neuronal loss and blood-brain barrier (BBB) impairment in vascular dementia (VaD). However, the relationship and the molecular mechanisms between BBB dysfunction and neuronal loss remain elusive. Objective: We explored the reasons for neuron loss following CCH. Methods: Using permanent bilateral common carotid artery occlusion (2VO) rat model, we observed the pathological changes of cortical neurons and BBB in the sham group as well as rats 3d, 7d, 14d and 28d post 2VO. In order to further explore the factors influencing neuron loss following CCH with regard to cortical blood vessels, we extracted cortical brain microvessels at five time points for transcriptome sequencing. Finally, integrin receptor a4β1 (VLA-4) inhibitor was injected into the tail vein, and cortical neuron loss was detected again. Results: We found that cortical neuron loss following CCH is a continuous process, but damage to the BBB is acute and transient. Results of cortical microvessel transcriptome analysis showed that biological processes related to vascular inflammation mainly occurred in the chronic phase. Meanwhile, cell adhesion molecules, cytokine-cytokine receptor interaction were significantly changed at this phase. Among them, the adhesion molecule VCAM1 plays an important role. Using VLA-4 inhibitor to block VCAM1-VLA-4 interaction, cortical neuron damage was ameliorated at 14d post 2VO. Conclusion: Injury of the BBB may not be the main reason for persistent loss of cortical neurons following CCH. The continuous inflammatory response within blood vessels maybe an important factor in the continuous loss of cortical neurons following CCH.

Abstract Alzheimer's disease (AD) is an age-related progressive neurodegenerative disease, about 10% of AD patients are called early-onset familial AD (EOFAD), which is mainly linked to the point mutations in genes encoding Presenilins (PS1 and PS2). Mutations in PS2 are extremely rare and PS2 mutations have not received enough attention. Recently studies have found that Rho GTPase was closely related to the pathogenesis of AD. In this study, we used transcriptome sequencing in PS2 siRNA SH-SY5Y cells and found a group of differential expression genes (DEGs) play a key role in the regulation of GTPase activity. Among those DEGs, the most significantly down regulated was Rho guanine nucleotide exchange factor5 (ARHGEF5). The GTPase activity in PS2 siRNA cells decreased significantly. Then we found that the expression of ARHGEF5 and the GTPase activity of Mitochondrial Rho GTPase 2 (Miro2) in PS2 D439A mutant SH-SY5Y cells decreased significantly. We found for the first time that PS2 can bind to Miro2, and PS2 D439A mutation reduced the binding between PS2 and Miro2, reduced the expression of Miro2, and resulted in the imbalance of mitochondrial fusion/fission dynamics. In conclusion, PS2 gene knockdown may participate in the pathogenesis of AD through the regulation of GTPase activity. The imbalance of mitochondrial dynamics mediated by PS2 D439A mutation through regulating Miro2 expression and Miro2-GTPase activity may be one of the potential pathogenic mechanisms of AD.

The blood-brain barrier (BBB) comprises a single layer of endothelial cells and maintains a safe and homeostatic environment for proper neuronal function and synaptic transmission. BBB is not a discrete physical barrier, but a complex, dynamic, and adaptable interface. BBB continues to mature under the influence of the neural environment within a short period of time after birth. However, the basic mechanism of BBB formation and maintenance remains a mystery. Early studies have identified two structural characteristics of microvascular endothelium: special tight junctions (TJs) and a very low transcellular vesicle transport rate. Previous studies believed that BBB damage was mainly due to the destruction of tight junctions, and the role of vesicle transcytosis was neglected, so there was a lack of research on its impact on blood-brain barrier. It is urgent to get a better clarification of the unique structural and functional characteristics of the BBB endothelium to explain the role of BBB injury in neurological diseases. RNA sequencing was used to study the molecular characterization of cerebral cortex vascular endothelium by isolating them from neonatal, adolescent and adult rats. For investigation the maintenance mechanism of the BBB, we focused on the cellular and molecular regulation of barrier formation and the two characteristics of microvascular endothelial cells. Interestingly, we found that during the development of the blood-brain barrier, although the tight junctions gradually mature, endothelial cell transcytosis is gradually enhanced, resulting in an increase in the permeability of the blood-brain barrier. This study suggested that under physiological conditions, low vesicle transport is playing an important role in maintaining the integrity of the blood-brain barrier. This study not only summarized the unique characteristics of microvascular endothelial cells, but also illustrated a clarified mechanism of the development and maintenance of BBB which can provide new therapeutic opportunities for central nervous system drug delivery. Raw data of RNA sequencing were deposited in NCBI Sequence Read Archive database (PRJNA790676).

BACKGROUND:Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a typical neurodegenerative disease associated with mitochondrial dysfunction. Methylation of the D-loop region and mitochondrial DNA copy number (mtDNAcn) play a critical role in the maintenance of mitochondrial function. However, the association between D-loop region methylation, mtDNAcn and CADASIL remains unclear.METHODS:Overall, 162 individuals were recruited, including 66 CADASIL patients and 96 age- and sex-matched controls. After extracting genomic DNA from the peripheral white blood cells, levels of D-loop methylation and mtDNAcn were assessed using MethylTarget sequencing and real-time PCR, respectively.RESULTS:We observed increased mtDNAcn and decreased D-loop methylation levels in CADASIL patients compared to the control group, regardless of gender stratification. Besides, we found a negative correlation between D-loop methylation levels and mtDNAcn. Mediation effect analysis shows that the proportion of the association between mtDNAcn and CADASIL that is mediated by D-loop methylation is 11.6% (95% CI 5.6, 22.6). After gender stratification, the proportions of such associations that are mediated by D-loop methylation in males and females were 7.2% (95% CI 2.4, 19.8) and 22.0% (95% CI 7.4, 50.1), respectively.CONCLUSION:Decreased methylation of the D-loop region mediates increased mtDNAcn in CADASIL, which may be caused by a compensatory mechanism of mitochondrial dysfunction in patients with CADASIL.

Background: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) caused by NOTCH3 mutations is the most common monogenic hereditary pattern of cerebral small vessel disease. The aggregation of the mutant NOTCH3 may play a cytotoxic role in CADASIL. However, the main mechanism of this process remains unclear. Objective: We aimed to investigate the possible pathogenesis of the mutant NOTCH3 in CADASIL. Methods: The clinical information of two pedigrees were collected and analyzed. Furthermore, we constructed cell lines corresponding to this mutation in vitro. The degradation of the extracellular domain of NOTCH3 (NOTCH3(ECD)) was analyzed by Cycloheximide Pulse-Chase Experiment. Flow cytometry and cell counting kit-8 assay were performed to observe the effects of the NOTCH3 mutation on mitochondrial function and apoptosis. Results: We confirmed a de novo heterozygous missense NOTCH3 mutation (c.1690G > A, p. A564T) in two pedigrees. In vitro, the NOTCH3(ECD) aggregation of A564T mutant may be related to their more difficult to degrade. The mitochondrial membrane potential was attenuated, and cell viability was significant decreased in NOTCH3(ECD) A564T group. Interestingly, BAX and cytochrome c were significantly increased, which are closely related to the mitochondrial-mediated pathway to apoptosis. Conclusion: In our study, the aggregation of NOTCH3(ECD) A564T mutation may be associated with more difficult degradation of the mutant, and the aggregation may produce toxic effects to induce apoptosis through the mitochondrial-mediated pathway. Therefore, we speculated that mitochondrial dysfunction may hopefully become a new breakthrough point to explain the pathogenesis of cysteine-sparing NOTCH3 mutations.

Background: Exosomes are nano-sized extracellular vesicles which are secreted by cells and usually found in body fluids. Previous research has shown that exosomal secretion and autophagy-lysosomal pathway synergistically participates in intracellular abnormal protein elimination. The main pathological manifestations of Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is abnormal accumulation of mutant NOTCH3, and CADASIL vascular smooth muscle cells have been found with autophagy-lysosomal dysfunction. However, whether plasma exosomes change in CADASIL patients is still unclear. Objective: We are aimed to investigate the differences of plasma exosomes between CADASIL patients and healthy controls. Methods: The subjects included 30 CADASIL patients and 30 healthy controls without NOTCH3 mutation. The severity of white matter lesions (WMLs) of CADASIL patients was quantified by Fazekas score. Transmission electron microscopy and nanoparticle tracking analysis were performed to characterize plasma exosomes. In addition, NOTCH3, Neurofilament light and Aβ42 levels in plasma exosomes were quantified by enzyme-linked immunosorbent assays. Results: We found that exosomes from CADASIL patients were lower in quantity. In addition, CADASIL plasma exosomes had significantly lower levels of NOTCH3 and significantly increased levels of NFL than those of matched healthy subjects. Interestingly, plasma exosome NOTCH3 levels of CADASIL patients significantly correlated with severity of WMLs. Conclusion: The exosome NOTCH3 may be related to the pathological changes of CADASIL, which provides a basis for the pathogenesis research of CADASIL. In addition, plasma exosome NOTCH3 and NFL levels may act as biomarkers to monitor and predict disease progression and measure therapeutic effectiveness in the future clinical trials.