Biology subjects

Suzuki, K.

Publications and source records attributed to Suzuki, K..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

STAT3 regulates basal cell identity and morphogenesis during early esophageal development

The transcription factor STAT3 plays broad roles in epithelial biology, yet its function in human esophageal development remains undefined. Using 2D and 3D human induced pluripotent stem cell (hiPSC)-derived platforms, we investigated how STAT3 regulates esophageal epithelial differentiation. We find that STAT3 is dispensable for definitive endoderm and anterior foregut endoderm specification but becomes essential during the transition to esophageal progenitor cells (EPCs). Inhibition of STAT3, via CRISPR-mediated knockout or siRNA, impairs the expression of key EPC and differentiation markers, including TP63, and disrupts 3D organoid formation. These defects are accompanied by reduced epithelial proliferation. Notably, STAT3 is highly expressed in human fetal esophageal tissues and hiPSC-derived organoids, while its deletion in the developing mouse esophagus does not affect epithelial architecture, highlighting species-specific differences. Together, these findings identify STAT3 as a critical determinant of basal cell identity and epithelial morphogenesis, revealing a developmental checkpoint in early human esophageal lineage commitment.

developmental biology↗

bioRxiv2025

Stem cell-derived cardiomyocyte migration through TGF-β signalling in the context of myocardial infarction

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) hold significant promise for cardiac regeneration therapies. However, the efficacy of such treatments depends on the ability of transplanted cells to migrate and integrate into the damaged myocardium, a process that remains poorly understood. In this study, we investigated the migratory behaviour of hiPSC-CMs using homogenised rat MI tissue to simulate myocardial infarction (MI) in vitro. Transwell migration assays demonstrated a concentration-dependent chemotactic response, with hiPSC-CM migration increasing up to threefold toward MI tissue homogenate. Wound healing assays further confirmed enhanced migration under MI-mimetic conditions. Bulk RNA sequencing revealed activation of the TGF-{beta} signalling pathway as a key regulator of this response. Inhibition of TGF-{beta} signalling, both pharmacologically and through antibody neutralisation, significantly reduced hiPSC-CM migration. These findings uncover a previously underappreciated chemotactic capability of hiPSC-CMs and identify TGF-{beta} signalling as a central mediator, offering new mechanistic insights and potential therapeutic targets to improve the integration and efficacy of hiPSC-CM-based cardiac regeneration strategies.

cell biology↗

bioRxiv2025

The interferon response signature links to increased expression of transposable elements in neutrophils of systemic lupus erythematosus patients

BackgroundSystemic lupus erythematosus (SLE) is a spontaneous systemic auto-immune condition for which the inciting factors and genetic basis are generally unknown. Although heterogeneous in its manifestations and severity, SLE involves chronic inflammation along with sustained autoantibody production. The root causes and pathophysiology of the inflammation and breaches of tolerance are incompletely understood, but neutrophils are thought to be important elements of the pathophysiology. Type I interferons (IFN) in the bloodstream and an IFN-stimulated gene (ISG) signature in circulating leukocytes, including neutrophils, are common features in many patients. Earlier work has provided evidence of increased levels of transcripts derived from transposable elements (TEs) in peripheral blood cells of SLE patients. Using six leukocyte types, including neutrophils, we tested the correlation of TE expression with disease severity and explored the relationships between increased ISG and TE expression with attention to the genomic locations of the expressed TEs. ResultsWe reanalysed previously published data from neutrophils and other leukocytes of SLE patients sub-divided into ISG-high (termed IFNpos, n=12) and ISG-low (termed IFNneg, n=11) patients in the original study, examining RNA-seq data from B and T lymphocytes, conventional and plasmacytoid dendritic cells (DC), monocytes and PMN of IFNpos and IFNneg SLE patients compared to healthy controls. SLE patients pre-stratified as IFNneg showed no significant increase in TE expression. All IFNpos cell types had similar amounts of total TE-encoded RNA, but among the 6 cell types, PMN had the highest number of differentially expressed TEs and ISGs in IFNpos SLE patients compared to healthy controls. There was a strong correlation between expression of several specific TE families and disease activity assessed at the time of the visit. Most upregulated TEs ([~]80%) were present in introns of upregulated genes, and [~]67% of these were ISGs. By mapping expressed TEs in ISGs, we found that high intronic TE expression correlated strongly with increased ISG expression as well as with splicing alterations in annotated exons flanking expressed TEs. Consistent with autonomous TE expression, upregulated TEs were also observed at intergenic sites distant from annotated genes, perhaps due to weakening of heterochromatin integrity. ConclusionsOur findings show a strong association and suggest mechanistic relationships between increased TE expression and IFN responses in multiple types of leukocytes centrally involved in SLE pathogenesis. Although limited by short-read RNA-seq technology, our analyses support selective upregulation of some TEs independent from the regulation of conventional genes, concurrent with many intron-localized TEs whose expression tracks with ISGs. The data emphasize the need for long-reads sequencing to understand the causes and consequences of high TE expression in SLE and other autoimmune/inflammatory disorders. Important questions include whether TE expression in introns of ISGs and other genes is independently regulated or reflects exonization or partial intron retention, and how frequently it correlates with splicing variations in adjacent exons.

immunology↗

bioRxiv2025

Mechanism of bridge-type phospholipid transfer by Atg2 for autophagosome biogenesis

Autophagosome biogenesis requires delivery of millions of phospholipids. In budding yeast, Atg2 and Atg18 couple the ER to the isolation membrane for lipid transport, yet the mechanism is poorly understood. Combining molecular dynamics simulations, in vitro imaging-based lipid transfer assays, and in vivo analyses, we show that Atg1-mediated phosphorylation activates Atg2 as a lipid-transfer bridge. Simulations reveal that Atg2 contains a water-excluding hydrophobic cavity that accommodates [~]25 phospholipids with bilayer-like fluidity. Atg1 phosphorylates an N-terminal helix of Atg2 in vitro and in vivo, thereby opening the ER-facing entrance to the Atg2 cavity and enabling lipid flow between membranes in silico and in vitro. Consistently, phosphodeficient but not phosphomimetic mutations impair autophagy. Cavity narrowing along the conduit disrupts lipid alignment in silico, phosphorylation-activated bridge-type lipid transfer in vitro, and ER-to-isolation-membrane lipophilic dye flow and autophagosome expansion in vivo. These data suggest that Atg1 gates Atg2-mediated bridge-type lipid transport to build autophagosomes.

cell biology↗

bioRxiv2025

Proteomic profiling of bacterial extracellular vesicles for exploring ovarian cancer biomarkers

Extracellular vesicles (EVs) are present in body fluids and act as disease biomarkers. Emerging evidence has proven that EVs are released not only from mammalian cells but also from bacteria. Ovarian cancer has a dismal prognosis because of difficulties in early detection. This study aimed to identify bacterial EV (BEV) proteins associated with ovarian cancer. Fifteen patients with ovarian cancer or benign tumors were recruited, and EVs were isolated from the ascites. BEVs were recovered from seven in vitro-cultured strains of bacteria present in the vaginal microbiota, and LC-MS/MS analysis was performed. The detected peptide data were annotated to both human and bacterial references, and the human data showed that the profiles of cancer EVs were distinct from those of patients with benign tumors. As analyzed by bacterial proteins, P15636_Protease1 was found as the BEV-associated protein highly expressed in patients with cancer. To distinguish patients with cancer, the area under the curve was 0.88 (95% CI, 0.64-1.00). In addition, homology analysis showed that P15636_Protease1 is a unique protein only detected in bacteria. In this study, ovarian cancer-specific bacterial proteins were identified on EVs, and BEVs in bodily fluids are promising in the discovery of disease biomarkers.

cancer biology↗

bioRxiv2025

Reversible One-way Lipid Transfer at ER-Autophagosome Membrane Contact Sites via Bridge-like Lipid Transfer Protein Atg2

Bridge-like lipid transfer proteins (LTPs) contain a repeating {beta}-groove domain and long hydrophobic grooves that act as bridges at membrane contact sites (MCSs) to efficiently transfer lipids. Atg2 is one such bridge-like LTP essential for autophagosome formation, during which a newly synthesized isolation membrane (IM) emerges and expands through lipid supply. However, studies on Atg2-mediated lipid transfer are limited to in vitro studies due to the lack of a suitable probe for monitoring phospholipid dynamics in vivo. Here, we characterized the lipophilic dye octadecyl rhodamine B (R18), which internalizes and labels the endoplasmic reticulum (ER) in a manner that requires flippases and oxysterol-binding protein-related proteins. Using R18, we demonstrated phospholipid transfer from the ER to the IM during autophagy in vivo. Upon autophagy termination, we observed reversible phospholipid flow from the IM to the ER in response to environmental changes. Our findings highlight the critical role of bridge-like LTPs in MCS-mediated phospholipid homeostasis.

cell biology↗

bioRxiv2025

Visualization of functional and effective connectivity underlying auditory descriptive naming

ObjectiveWe visualized functional and effective connectivity within specific white matter networks in response to auditory descriptive questions. MethodsWe investigated 40 Japanese-speaking patients with focal epilepsy and estimated connectivity measures using cortical high-gamma dynamics and MRI tractography. ResultsHearing a wh-interrogative at question onset enhanced inter-hemispheric functional connectivity, with left-to-right callosal facilitatory flows between the superior-temporal gyri, contrasted by functional connectivity diminution with right-to-left callosal suppressive flows between dorsolateral prefrontal regions. Processing verbs associated with concrete objects or adverbs increased left intra-hemispheric connectivity, with bidirectional facilitatory flows through extensive white matter pathways. Questions beginning with what, compared to where, induced greater neural engagement in the left posterior inferior-frontal gyrus at question offset, linked to enhanced functional connectivity and bidirectional facilitatory flows to the temporal lobe neocortex via the arcuate fasciculus. During overt responses, inter-hemispheric functional connectivity was enhanced, with bidirectional callosal flows between Rolandic areas, and individuals with higher IQ scores exhibited less prolonged neural engagement in the left posterior middle frontal gyrus. ConclusionsVisualization of directional neural interactions within white matter networks during overt naming is feasible. SignificancePhrase order may influence network dynamics in listeners, even when presented with auditory descriptive questions conveying similar meanings.

neuroscience↗

bioRxiv2025

Androgen receptors expressed in the primary sensory neurons regulate mechanical pain sensitivity

The expression of hormonal receptors in pain-processing regions complicates understanding the hormonal effects on pain mechanisms. This study investigates androgen receptor (AR) involvement in pain sensitivity and sex differences in pain perception. Mechanical pain thresholds were higher in normal male mice compared to gonadectomized (GDX) male and normal female mice, correlating with serum testosterone levels. In the dorsal root ganglia (DRG), AR was expressed in normal males but undetectable in GDX males and normal females. In male sensory neuron-selective AR conditional knockout (AR-cKO) mice, mechanical pain thresholds were significantly lower than in wild-type males. In female mice, administration of testosterone propionate or dihydrotestosterone significantly raised mechanical pain thresholds, accompanied by increased AR expression in the DRG. This effect was abolished in AR-cKO females, consistent with male findings. These results indicate that primary sensory neurons are critical targets of androgen signaling in regulating mechanical pain sensitivity.

neuroscience↗

bioRxiv2025

Operant House: A Versatile Open-Source Platform for Automated Operant Conditioning Testing of Mice in Home Cages

Operant conditioning is a valuable method for studying cognitive functions, yet its adoption is limited by low throughput, labor intensity, and high costs. Here, we developed "Operant House," a low-cost, programmable device featuring a touchscreen, retractable levers, and a water reward port, designed for flexible, automated operant conditioning tasks. To validate its utility, we implemented two protocols to assess working memory in mice: a delayed non-match-to-position test and a two-choice spatial discrimination test. Using these protocols, we examined a mouse model of Alzheimers disease carrying familial Alzheimers disease-associated amyloid precursor protein mutations. Results revealed significant working memory deficits as early as 5 months of age. These findings highlight the Operant House as a cost-effective, high-throughput platform for evaluating higher cognitive functions in mice, offering an accessible tool for investigating models of neurological and neuropsychiatric disorders.

neuroscience↗

bioRxiv2024

Investigating the role of sensorimotor spatial dependencies in shaping conscious access to virtual 3D objects

According to sensorimotor accounts of perceptual experience, the subjective veridicality of an object (the sense of its presence) builds up gradually as one learns how changes in sensory inputs depend on bodily movements. To investigate how sensorimotor interactions shape visual experience, we designed a virtual-reality-based study that allowed us to manipulate the complexity of spatial dependencies governing interactions with unfamiliar 3D objects. Participants had to learn to manually control fully visible objects that could move in congruent, opposite, novel (orthogonal), or random directions in response to their movements. The sensorimotor control tasks occurred alternately with a continuous flash suppression (CFS) task evaluating the access of stationary objects to visual awareness, operationalised as the time taken for a 3D object to break the interocular suppression. We hypothesised that objects whose motion was experienced as depending on actions in a lawful, and thus encodable, manner (i.e., according to a congruent, opposite, or novel - but not random - dependency) would overcome suppression faster than objects moving randomly in response to actions (for which there is no world-related statistical structure to learn). However, while performance in the sensorimotor tasks consistently decreased along with the difficulty of the conditions (i.e., congruent > opposite > novel > random), the pre-registered analysis yielded no significant differences in breakthrough times of objects manipulated under different coupling rules. An exploratory analysis assessing whether the acquisition of sensorimotor mastery was associated with reduced breakthrough times also revealed no significant effects. Thus, our results suggest that ones knowledge of how an object responds to action does not play a salient role in determining conscious access to visual stimuli. This extends previous evidence for a general ineffectiveness of sensorimotor spatial manipulations in interocular suppression paradigms. Notably, in all conditions, object movement remained tightly coupled (i.e., contingent) to the participants actions - and given such stimuli have already been shown to break suppression faster than uncoupled/pre-recorded visual inputs - it is possible that sensorimotor contingency was a sufficiently salient factor to override any influences related to how identifiable specific spatial dependencies were. HighlightsLearning sensorimotor control over objects was examined in novel VR tasks. We varied the complexity of spatial dependencies between manual and visual rotations. Controllable objects were expected to enter visual awareness faster in b-CFS. No differences in breakthrough times for differently complex spatial coupling rules. Sensorimotor contingency outweighs spatial congruence in affecting visual awareness.

neuroscience↗

bioRxiv2024

TMEM55A-mediated PI5P signaling regulates α-cell actin depolymerization and glucagon secretion

Diabetes is associated with the dysfunction of glucagon-producing pancreatic islet -cells, although the underlying mechanisms regulating glucagon secretion and -cell dysfunction remain unclear. While insulin secretion from pancreatic {beta}-cells has long been known to be partly controlled by intracellular phospholipid signaling, very little is known about the role of phospholipids in glucagon secretion. Here we show that TMEM55A, a lipid phosphatase that dephosphorylates phosphatidylinositol-4,5-bisphosphate (PIP2) to phosphatidylinositol-5-phosphate (PI5P), regulates -cell exocytosis and glucagon secretion. TMEM55A knockdown in both human and mouse -cells reduces exocytosis at low glucose, and this is rescued by the direct reintroduction of PI5P. This does not occur through an effect on Ca2+ channel activity, but through a re-modelling of cortical F-actin dependent upon TMEM55A lipid phosphatase activity which occurs in response to oxidative stress. In summary, we reveal a novel pathway by which TMEM55A regulates -cell exocytosis by manipulating intracellular PI5P level and the F-actin network.

cell biology↗

bioRxiv2024

Molecular Correlates of Glycine Receptor Activity in Human β Cells

ObjectivesGlycine acts in an autocrine positive feedback loop in human {beta} cells through its ionotropic receptors (GlyRs). In type 2 diabetes (T2D), islet GlyR activity is impaired by unknown mechanisms. We sought to investigate if the GlyR dysfunction in T2D is replicated by hyperglycemia per se, and to further characterize its action in {beta} cells and islets. MethodsGlyR-mediated currents were measured using whole-cell patch-clamp in human {beta} cells from donors with or without T2D, or after high glucose (15 mM) culture. We also correlated glycine-induced current amplitude with transcript expression levels through patch-seq. The expression of the GlyR 1, 3, and {beta} subunit mRNA splice variants was compared between islets from donors with and without T2D, and after high glucose culture. Insulin secretion from human islets was measured in the presence or absence of the GlyR antagonist strychnine. ResultsAlthough gene expression of GlyRs was decreased in T2D islets, and {beta} cell GlyR-mediated currents were smaller, we found no evidence for a shift in GlyR subunit splicing. Glycine-induced currents are also reduced after 48 hours culture of islets from donors without diabetes in high glucose, where we also find the reduction of the 1 subunit expression, but an increase in the 3 subunit. We discovered that glycine-evoked currents are highly heterogeneous amongst {beta} cells, inversely correlate with donor HbA1c, and are significantly correlated to the expression of 92 different transcripts and gene regulatory networks (GRNs) that include CREB3(+), RREB1(+) and ZNF697(+). Finally, glucose-stimulated insulin secretion is decreased in the presence of the GlyR antagonist strychnine. ConclusionsWe demonstrate that glucose can modulate GlyR expression, and that the current decrease in T2D is likely due to the receptor gene expression downregulation, and not a change in transcript splicing. Moreover, we define a previously unknown set of genes and regulons that are correlated to GlyR-mediated currents and could be involved in GlyR downregulation in T2D. HighlightsO_LIGlycine-evoked currents in {beta} cells are lower in T2D and after high glucose culture C_LIO_LIGlyR gene expression is reduced in T2D, with no shift in splice variant expression C_LIO_LIGlyR inhibition with strychnine decreases insulin secretion C_LIO_LIWe define transcripts and gene regulatory networks correlated to glycine-induced currents C_LI

cell biology↗

bioRxiv2024

Downregulation of astrocytic C3 production alleviates neuronal mitochondrial dysfunction in tauopathy models

Neuronal mitochondrial dysfunction is associated with cognitive decline in neurodegenerative disorders such as Alzheimers Disease (AD). In this study, multiple pieces of evidence proved that phosphorylated tau (p-Tau) caused mitochondrial swelling and dysfunction in neurons. In a novel in vitro newborn neurons culture system, we discovered mitochondrial swelling and dysfunction were associated with increased p-Tau, leading to necroptosis activation, which was induced by Complement C3 (C3) produced from activated astrocytes. In the in vivo tauopathy mouse models, the effects of astrocytic C3 on tau-associated mitochondrial dysfunction and necroptosis were also discovered in hippocampal newborn neurons, and we directly showed that p-Tau aggregation was associated with mitochondria swelling in the hippocampal neurons by electron microscopy analysis. In addition, we proved the ability of compound anserine, which can block Tak1-Ikk dependent NF-{kappa}B activation, to further down-regulate astrocytic C3 production and alleviate neuronal mitochondrial dysfunction in vitro and in vivo, respectively. Down-regulation of astrocyte C3-production by anserine could also rescue mortality as well as cognitive and motor functions. Our findings first reported the contribution of p-Tau on neuronal mitochondrial dysfunction and proposed the therapies that down-regulate astrocytic C3 production have a potential role in alleviating this neurotoxic effect.

neuroscience↗

bioRxiv2024

Reconstruction of functional olfactory sensory tissue from embryonic nasal stem cells

During the development of the olfactory epithelium (OE), olfactory sensory neurons (OSNs) express only one member of the odorant receptor (OR) gene family, and OSNs expressing the same OR converge their axons to the same set of glomeruli on the olfactory bulb (OB). The resulting odor maps allow mice to discriminate more than 100,000 different odorants using about 1,000 ORs. It remains elusive how odor maps are formed. Here, we show a means of forming OE organoids with pseudostratified structure from mouse embryonic OE stem cells. Single-cell RNA sequencing revealed that the OE organoids give rise to all the OE cellular lineages and undergo active neurogenesis. We also found that most OSNs in OE organoids exclusively express only one type of ORs and exhibit a unique molecular code of axon guidance-related genes that can discriminate between OR classes. Thus, OE organoids could be a useful model for studying olfactory nervous system development.

developmental biology↗

bioRxiv2024

Ca2+-driven PDIA6 phase separation to ensure proinsulin quality control

The endoplasmic reticulum (ER) plays key roles in protein quality control1,2 and dynamic Ca2+ storage3,4 in eukaryotic cells. However, the protein homeostasis (proteostasis) system that regulates these ER functions is still incompletely characterised. Previous study revealed the importance of oligomerization in the function PDIA1, an ER-resident disulfide isomerase and molecular chaperone, regulates oligomeric states in accordance with client folding5. This result suggests that at least some of the 20 members of other PDI family may undergo regulated self-assembly in order to optimally function. Here, we show that Ca2+ triggers the phase separation of PDIA6 into liquid-like condensates. In contrast to the condensation mechanism observed for proteins containing low-complexity domains, our results indicate that transient but specific electrostatic interactions occur between the first and the third folded thioredoxin-like domains of PDIA6. We further show that the Ca2+-driven condensation of PDIA6 recruits PDIA3 and proinsulin, thus increasing their local concentrations. This process results in the 30-fold enhancement of proinsulin folding and in the inhibition of proinsulin aggregation. Our findings shed light on a condensation-driven Ca2+-mediated proteostasis cascade in the ER by revealing how the efficiency of the protein folding process can be enhanced within quality control granules.

biochemistry↗

bioRxiv2024

PD-1 negatively regulates helper T cell differentiation into Th2

Programmed Cell Death Protein-1 (PD-1) represents endogenous mechanisms of negative immunoregulation. While the modulation of effector functions has been the major focus of PD-1 research, quick PD-1 upregulation in naive T cells starting 1 h after priming raised a possibility that PD-1 also affects the development of effector T cells. The role of PD-1 in functional differentiation into Th1 and Th2 has been unclear. In murine naive CD4+ T cell activation, we found that PD-1 stimulation during the early stage of T cell activation strongly impaired Th2 cell development, while Th1 cell induction was relatively resistant to this immunosuppressive signaling. The steep decline in Th2 cell induction suggested the significance of PD-1 in allergic inflammation. Treatment with anti-human PD-1 agonist antibody inhibited allergic inflammation in human PD-1-knock-in mice as shown by the reduction of Th2 cells, IgE levels and eosinophilic infiltration. This study shows that PD-1 regulates not only the intensity but also the quality of immune response by deviating Th differentiation. PD-1 stimulators are projected to be valuable in suppressing various forms of inflammatory activities, but the efficacy against Th2-dominant immune response may be particularly high.

immunology↗

bioRxiv2024

3-nitrotyrosine shortens axons of a non-dopaminergic neuron by inhibiting mitochondrial motility

3-nitrotyrosine (3-NT), a byproduct of oxidative/nitrosative stress, is implicated in age-related neurodegenerative disorders. Existing literature indicates that free 3-NT becomes integrated into the carboxy-terminal domain of -tubulin through the tyrosination/detyrosination cycle. Independently of this integration, 3-NT has been linked to the cell death of dopaminergic neurons. Given the critical role of tyrosination/detyrosination in governing axonal morphology and function, the substitution of tyrosine with 3-NT in this process may potentially disrupt axonal homeostasis, although this aspect remains underexplored. In this study, we examined the impact of 3-NT on the axons of cerebellar granule neurons, representing non-dopaminergic neurons. Our observations revealed axonal shortening, which correlated with the incorporation of 3-NT into -tubulin. Importantly, this axonal effect was observed prior to the onset of cellular death. Furthermore, 3-NT was found to diminish mitochondrial motility within the axon, resulting in a subsequent reduction in mitochondrial membrane potential. The suppression of syntaphilin, a protein responsible for anchoring mitochondria to microtubules, reversed the 3-NT-induced decrease in mitochondrial motility, consequently restoring axonal elongation. These findings underscore the inhibitory role of 3-NT in axonal elongation by impeding mitochondrial movement, implying its potential involvement in axonal dysfunction within non-dopaminergic neurons.

neuroscience↗

bioRxiv2024

A novel VCP modulator, KUS121, attenuates atherosclerosis progression by maintaining intracellular ATP and mitigating ER stress in endothelial cells

BackgroundEndoplasmic reticulum (ER) stress signaling pathways have pivotal roles in atherosclerosis progression. Recently, we have developed Kyoto University Substance (KUS) 121, which selectively inhibits ATPase activities of valosin-containing protein (VCP) and consequently saves intracellular ATP consumption and mitigates ER stress. Methods and ResultsWe assessed the efficacy of KUS121 against atherosclerosis by its daily injection into Apoe-/- mice fed with Western Diet (WD) for 8 weeks. Consequently, KUS121 treatment reduced atherosclerosis progression by approximately 40% in atherosclerotic plaques. Interestingly, we found that C/EBP homologous protein (CHOP), an established ER stress marker, was mainly expressed in plaque endothelium. Therefore, we assessed the action of KUS121 in endothelial cells using the human endothelial cell line (EA.hy926 cells). As a result, KUS121 prevented ER stress-induced apoptosis and downregulated the IRE1 (Inositol-requiring enzyme) -associated inflammatory pathways. Consistent with these in vitro findings, KUS121 treatment also significantly reduced endothelial apoptosis assessed by TUNEL staining and inflammation examined by immunostaining of Nuclear factor kappa B (NF-{kappa}B) and Intercellular adhesion molecule (ICAM) 1 at plaque endothelium. We also demonstrated that KUS121 maintained ATP levels in EA.hy926 cells and atherosclerotic plaque lesions using the single-wavelength or the FRET-based fluorescent ATP sensor. Supplementation of intracellular ATP by Methyl pyruvate (MePyr) attenuated ER stress-induced apoptotic and inflammatory pathways in endothelial cells, which could be the main mechanism how KUS121 reduces ER stress. ConclusionsKUS121 can be a new therapeutic option for atherosclerotic diseases by maintaining intracellular ATP levels and attenuating ER stress-induced apoptosis and inflammation in plaque endothelium.

pathology↗