Search bioRxiv⌕ Search

Biology subjects

Kim, H. Y.

Publications and source records attributed to Kim, H. Y..

At least 19 recordsLinked to original sources

TAPAS: Learned integration of AlphaFold3 confidence and geometric features for TCR-pMHC binding prediction

Motivation Recent advances in biomolecular structure prediction, exemplified by AlphaFold3, have opened new opportunities for the prediction of TCR-pMHC binding specificity. Although individual AlphaFold3 confidence metrics provide informative binding signals, their predictive performance varies across datasets, highlighting the need to combine complementary signals rather than rely on any single metric. Results We present TAPAS, a tabular learning framework that integrates AlphaFold3-derived interface confidence and structural geometry with sequence embeddings. Although no single zero-shot metric was the strongest across all benchmarks, TAPAS was consistently the top-ranked method on VDJdb and two external benchmarks, matching or exceeding the strongest zero-shot AlphaFold3 metric. Feature group ablation showed that the contributions of sequence, confidence, and geometric features varied across evaluation settings, and that combining them resulted in the best overall performance. These results highlight the value of integrating complementary structural and sequence features within a unified framework for robust TCR-pMHC binding prediction.

bioinformatics↗

Bumetanide Strengthens Residual Brain Bladder Communication After Spinal Cord Injury

Neurogenic bladder is one of the most disabling consequences of spinal cord injury (SCI), yet it remains unclear whether residual brain bladder communication persists after injury and can be therapeutically strengthened. Here, we integrated analysis of a clinical SCI cohort with studies in a mouse model that recapitulates key features of human neurogenic bladder. SCI markedly impaired both descending and ascending limbs of the spinobulbospinal micturition reflex, reducing bladder responses evoked by stimulation of the pontine micturition center (PMC) and bladder filling-induced activation of the periaqueductal gray. Despite this marked functional impairment, pseudorabies virus tracing, optogenetics, and machine learning assisted three dimensional imaging revealed persistent bladder connected neurons within the spared thoracic interlesion region. Neurons within this region remained responsive to descending PMC input, identifying the interlesion network as a candidate substrate for residual brain bladder communication. Early continuous intrathecal bumetanide improved urinary storage and emptying, enhanced descending PMC to bladder and ascending bladder to brain signaling, and increased the functional engagement of bladder-connected thoracic neurons without increasing urine production. Bumetanide also increased transsynaptic labeling between the bladder and PMC, consistent with enhanced polysynaptic brain bladder connectivity. Together, these findings indicate that brain bladder communication is not completely lost after SCI and may be supported by a functionally compromised residual spinal network that remains amenable to therapeutic reinforcement. Targeting spared autonomic circuitry may therefore provide a strategy for improving bladder function after SCI.

neuroscience↗

Capsular K-antigen Coats Outer Membrane Vesicles of Porphyromonas gingivalis

Periodontal disease is an inflammatory disorder that arises from dysbiosis of the subgingival microbiota, with Porphyromonas gingivalis acting as a keystone pathogen in the shift from health to disease. P. gingivalis employs multiple strategies to subvert host immune defenses, and its capsular K-antigen serves as a key virulence determinant. Here, a pre-adsorbed antiserum (pAds106) was generated by removing nonspecific antibodies using cells from a K-antigen-null mutant (W83{Delta}PG0106), resulting in exceptional specificity for the P. gingivalis K1-antigen. Immunofluorescence analysis revealed that the K-antigen preferentially coats outer membrane vesicles (OMVs), rather than attaching to the bacterial cell surface. This localization was further confirmed by ELISAs of density gradient ultracentrifuge-purified OMVs, with background signal detected in OMVs derived from K-antigen-deficient strains, non-K1-strains, and other oral Bacteroidetes. K-antigen-coated OMVs exhibited higher hydrophilicity and elicited weaker inflammatory responses compared to K-antigen-deficient OMVs, consistent with previously reported properties of encapsulated strains. Importantly, the antiserum detected K-antigen-coated OMVs in subgingival plaque from periodontal patients, suggesting that K-antigen is actively produced at diseased sites. These findings revise the prevailing view that K-antigen solely encapsulates the bacterial cell body and suggest that K-antigen-coated OMVs produced by P. gingivalis play distinct roles in immune evasion during periodontal disease.

microbiology↗

AUTOTAC-mediated targeted degradation of transthyretin aggregates ameliorates hereditary transthyretin amyloidosis

Hereditary transthyretin amyloidosis (hATTR) is characterized by extracellular deposition of amyloidogenic transthyretin (TTR) aggregates, yet the mechanisms governing their clearance remains poorly understood. Here, we identify a key role for the N-degron pathway in lysosomal degradation of the pathogenic TTRV30M variant. Misfolded intracellular TTRV30M was rapidly secreted and subsequently re-entered within 24 hours during cell-to-cell trafficking. The molecular chaperone R-BiP--N-terminally (Nt) arginylated HSPA5/BiP/GRP78-- associated with intracellular TTRV30M, and its Nt-arginine functioned as an agonist for the N-recognin sequestosome 1 (SQSTM1/p62). This interaction facilitated p62-dependent autophagosomal sequestration and lysosomal degradation of TTRV30M. To pharmacologically exploit this mechanism, we applied the AUTOTAC (AUTOphagy-TArgeting Chimera) platform, which enables the targeting of substrates to p62 for autophagic clearance. We developed Autotac 201 (ATC201), an 876-Da chimera designed to bind both the T4 pocket of aggregated TTR and p62, thereby promoting selective autophagic degradation. In cultured cells, ATC201 potently reduced intracellular TTRV30M aggregates in a manner depending on p62-mediated autophagy, exhibiting a DC of low nM. In hATTR model mice, ATC201 markedly lowered tissue TTR aggregate burden and restored autophagy pathway flux impaired by aggregate accumulation. Treatment improved nerve conduction parameters and reduced peripheral neuropathy scores, indicating functional rescue. ATC201 also led to preservation of muscle strength and attenuation of systemic amyloid deposition. Our findings reveal that the N-degron pathway orchestrates autophagic removal of TTR aggregates and demonstrate the therapeutic potential of AUTOTAC-based degraders for hATTR and other proteinopathies characterized by pathogenic protein aggregation.

cell biology↗

Fructose utilization by GM-CSF-differentiated macrophages aggravates autoimmune inflammation via MG-derived AGE-RAGE signaling

Excessive fructose intake is increasingly associated with metabolic and inflammatory pathologies; however, the direct impact of fructose metabolism on immune cell function remains insufficiently understood. Here, we demonstrate that GM-CSF-differentiated macrophages markedly upregulate the fructose-specific transporter GLUT5, enabling efficient fructose utilization through two complementary metabolic pathways. Using 13C-fructose tracing, we identified distinct carbon fluxes via a hexokinase (HK)-dependent glycolytic route and a ketohexokinase (KHK)-ALDOB-mediated fructolytic route. The HK-dependent pathway sustains glycolytic activity under glucose-limiting conditions, stabilizing HIF-1 and preserving pro-inflammatory gene expression. Conversely, the KHK-ALDOB axis increases dihydroxyacetone phosphate (DHAP) production, leading to methylglyoxal-derived advanced glycation end-products (MG-AGEs) that engage receptor for AGE (RAGE) signaling. This activation enhances MMP9 expression in macrophages and drives Th17 differentiation in CD4 T cells, amplifying inflammatory and tissue-remodeling processes. In vivo, fructose intake exacerbates autoimmune arthritis in SKG mice, and elevated fructose-driven glycolysis and MG-AGE accumulation are observed in monocytes from patients with rheumatoid arthritis. These results link fructose-driven carbonyl stress to macrophage effector programs and downstream T cell polarization. Collectively, these findings uncover a dual fructose metabolic program that integrates nutrient stress with persistent inflammation via the MG-AGE-RAGE axis and underscore the immunometabolic risks of excessive fructose exposure.

immunology↗

Second-order regulation: IFN-γ suppresses IL-17A-mediated neutrophilic inflammation.

BACKGROUNDT helper 1 (TH1) cells often accompany TH17 cells across diverse tissues in health and disease, including the lungs. However, roles for the TH1 effector cytokine, IFN-{gamma}, in TH17-driven type 3 inflammation is unclear. METHODSWe devised a reductionistic model to determine the role of IFN-{gamma} in IL-17A-driven inflammation during Streptococcus pneumoniae (Spn) infection in vivo. Briefly, intratracheal instillation of Spn along with recombinant TNF- and IL-17A was used to mimic rapid Spn-specific, TH17-driven, type 3 inflammation seen in lungs on memory recall infection with Spn. Co-instillation of recombinant IFN-{gamma} was used to probe the role for this TH1 cell-derived effector cytokine in anti-Spn immune response. Immune cellularity in bronchoalveolar lavage (BAL) was used to determine impacts of IFN-{gamma} on type 3 inflammation in murine airways. Mice sufficient for- or lacking-IFN-{gamma} or STAT1 were used to assess the immunoregulatory functions of IFN-{gamma} in vivo. RESULTSIFN-{gamma} promptly muted IL-17A-induced inflammatory cell accumulation in Spn-infected airways through a STAT1-dependent mechanism. Both female and male mice demonstrated similar anti-inflammatory effects of IFN-{gamma} on type 3 inflammation. Notably, the impact of IFN-{gamma} was more striking at lower cytokine concentrations. The immunoregulatory effect of IFN-{gamma} against TH17-driven type 3 inflammation was also evident in physiologically relevant settings: while immunized wildtype (WT) mice controlled lethal Spn infection, immunized IFN-{gamma} knockout mice exhibited even better Spn clearance. This heightened antimicrobial resistance, however, was accompanied by overt airway neutrophilia suggesting risk for immunopathology. CONCLUSIONSOur findings identify a distinct immunoregulatory mechanism that operates within non-lymphoid tissues, where IFN-{gamma} limits IL-17A-mediated type 3 inflammation via STAT1. Thus, the frequent accompaniment of TH17 cells with TH1 cells may represent a conserved mechanism that restrains immunopathological potential of TH17-driven neutrophilic inflammation via STAT1 signaling in non-lymphoid tissues.

immunology↗

Targeting serine dehydratase supports amino acid homeostasis and skin repair

Serine and glycine are altered in patients with metabolic disorders, and this dysregulation can lead to diverse pathologies1-6. Modulation of serine levels via diet can influence relevant phenotypes in mouse models of metabolic syndrome7,8. Here we identify serine dehydratase (Sds), a gluconeogenic hepatic enzyme involved in serine and threonine catabolism, as a key regulator of systemic serine and sphingolipid metabolism. We show that SDS is expressed and active in human liver tissue. Furthermore, Sds abundance strongly correlates with hepatic serine. This enzyme is highly active in BKS-db/db mice, which show amino acid alterations reminiscent of type 2 diabetes. Hepatic Sds overexpression increases serine and threonine degradation and promotes the accumulation of toxic 1-deoxysphingolipids (doxSLs). Conversely, Sds deletion dramatically increases systemic serine, glycine, and threonine while altering canonical and non-canonical sphingolipids. Finally, Sds deletion in BKS-db/db mice reduces skin doxSLs and accelerates wound healing. Our results demonstrate that Sds constrains serine levels in circulation and suggest therapeutic approaches for targeting this enzyme to improve chronic disorders.

physiology↗

Targeted degradation of pathologic tau aggregates via AUTOTAC ameliorates tauopathy

The pathogenesis of tauopathies including Alzheimers disease (AD) and progressive supranuclear palsy (PSP) involves the misfolding and aggregation of tau. Here, we employed AUTOTAC to induce the lysosomal degradation of intraneuronal tau aggregates. ATB2005A is a 734-Da chimera that simultaneously binds {beta}-sheet-rich tau aggregates and the autophagic receptor p62/SQSTM1, leading to autophagosomal sequestration and lysosomal co-degradation. In mouse models of tauopathies, orally administered ATB2005A lowered intraneuronal tau aggregates and exerted the therapeutic efficacy in neuroinflammation as well as cognition, behavior, and muscle movements. A Phase 2 clinical trial (U34401-4/2023/14) with companion dogs carrying canine cognitive dysfunction (CCD) demonstrated the efficacy of ATB2005A, as a veterinary medicine, to reverse the disease progression. ATB2005A is under Phase 1 clinical trial with human participants in Korea (202300697). These results validate AUTOTAC as a versatile platform for developing therapeutics to eradicate toxic protein aggregates in a wide range of proteinopathies.

neuroscience↗

Targeted degradation of pathogenic TDP-43 proteins in amyotrophic lateral sclerosis using the AUTOTAC platform

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive loss of motor neurons and the cytoplasmic aggregation of misfolded proteins in the spinal cord, including TAR DNA-binding protein-43 (TDP-43). More than 97% of ALS cases exhibit pathological TDP-43 inclusions, yet therapeutic strategies that can selectively eliminate these aggregates remain yet to be developed. Here, we employed the AUTOTAC (Autophagy-Targeting Chimera) to degrade TDP-43 aggregates via macroautophagy mediated by the N-recognin p62/SQSTM1 of the N-degron pathway. The AUTOTAC degraders ATC141 and ATC142 were designed to bind and link the oligomeric species of misfolded TDP-43 to p62, which induces the targeting of TDP-43 cargoes to phagophores for lysosomal co-degradation, while sparing monomeric TDP-43. ATC142 induced the degradation of pathological TDP-43 A315T species and its cleaved variant, TDP-25, with DC50 values of 1.25-9.6 nM. In ALS model mice expressing TDP-43 A315T in the spinal cord, oral administration of 10 mg/kg ATC141 with 24 doses reduced TDP-43 aggregates as well as GFAP+ astrocytes and Iba1+ microglia. ATC141 also exerted disease-modifying efficacy to reverse the disease progression in neuromuscular coordination and cognitive function. This oral drug is under Phase 1 clinical trials in South Korea with 76 healthy volunteers aiming to treat ALS, Alzheimers diseases (AD), and progressive supranuclear palsy (PSP). We suggest that AUTOTAC provides a novel strategy to treat a broad range of neurodegenerative diseases. TeaserAUTOTAC degraders induce lysosomal degradation of pathogenic TDP-43 aggregates in a mouse model of amyotrophic lateral sclerosis.

neuroscience↗

LARP6 regulates the mRNA translation of fibrogenic genes in liver fibrosis

Metabolic syndrome and excessive alcohol consumption result in liver injury and fibrosis, which is characterized by increased collagen production by activated Hepatic Stellate Cells (HSCs). LARP6, an RNA-binding protein, was shown to facilitate collagen production. However, LARP6 expression and functionality as a regulator of fibrosis development in a disease relevant model remains elusive. By using snRNA-sequencing, we show that LARP6 is upregulated mainly in HSCs of liver fibrosis patients. Moreover, LARP6 knockdown in human HSCs suppresses fibrogenic gene expression. By integrating eCLIP analysis and ribosome profiling in HSCs, we show that LARP6 interacts with mature mRNAs comprising over 300 genes, including RNA structural elements within COL1A1, COL1A2, and COL3A1 to regulate mRNA expression and translation. Furthermore, LARP6 knockdown in HSC attenuates fibrosis development in human liver spheroids. Altogether, our results suggest that targeting LARP6 in human HSCs may provide new strategies for anti-fibrotic therapy. HighlightsO_LILARP6 is upregulated in liver fibrosis, mainly in HSCs. C_LIO_LILARP6 knockdown in human HSCs reduces liver fibrosis development. C_LIO_LIOf the hundreds of gene targets, LARP6 interacts most with collagen mRNAs. C_LIO_LILARP6 regulates mRNA translation via interaction with 5UTRs. C_LI

cell biology↗

The novel linkage between Fuz and Gpr161 genes regulates sonic hedgehog signaling during mouse embryonic development.

Sonic hedgehog (Shh) signaling regulates embryonic morphogenesis utilizing primary cilia, the cell antenna acting as a signaling hub. Fuz, an effector of planar cell polarity (PCP) signaling, involves Shh signaling via cilia formation, while the G protein-coupled receptor 161 (Gpr161) is a negative regulator of Shh signaling. The range of phenotypic malformations observed in mice bearing mutations in either of these two genes is similar; however, their functional relations have not been previously explored. This study identified the genetic and biochemical link between Fuz and Gpr161 in mouse embryonic development. Fuz was genetically epistatic to Gpr161 via Shh signaling during mouse embryonic development. The FUZ biochemically interacted with GPR161, and Fuz regulated Gpr161 ciliary trafficking via {beta}-arrestin2. Our study suggested the novel Gpr161-Fuz axis that regulates Shh signaling during mouse embryonic development. Summary statementThis study illuminates the novel genetic and biochemical linkages between Fuz and Gpr161 to regulate sonic hedgehog signaling during mouse embryonic development.

genetics↗

TSpred: a robust prediction framework for TCR-epitope interactions based on an ensemble deep learning approach using paired chain TCR sequence data

Prediction of T-cell receptor (TCR)-epitope interactions is important for many applications such as cancer immunotherapy. However, due to the scarcity of available data, it is known to be a challenging task particularly for novel epitopes. Here, we propose TSpred, a new ensemble deep learning approach for the pan-specific prediction of TCR binding specificity based on paired chain TCR data. This method combines the predictive power of CNN and the attention mechanism to capture the patterns underlying TCR-epitope interactions. In particular, we design a reciprocal attention mechanism which contributes to higher model generalizability to unseen epitopes. We perform a comprehensive evaluation of our model and observe that TSpred achieves state-of-the-art performances in both seen and unseen epitope specificity prediction tasks. Our model performs consistently well across both of the two widely used negative sampling strategies, while avoiding the potential bias associated with each strategy. Also, compared to other predictors, it is more robust to bias related to peptide imbalance in the dataset. In addition, the reciprocal attention component of our model allows for model interpretability by capturing structurally important binding regions. Results indicate that TSpred is a robust and reliable method for the task of TCR-epitope binding prediction.

bioinformatics↗

Distinct eLPB ChAT projections for methamphetamine anxiety and relapse

Choline acetyltransferase-positive neurons in the external lateral parabrachial nucleus (eLPBChAT) send projections to PKC{delta}-positive (PKC{delta}+) neurons in lateral portion of central nucleus of amygdala (lCeAPKC{delta}) and oval portion of bed nucleus of the stria terminalis (ovBNSTPKC{delta}), forming eLPBChAT-lCeAPKC{delta} and eLPBChAT-ovBNSTPKC{delta} pathways. At least in part, the eLPBChAT neurons positively innervate lCeAPKC{delta} and ovBNSTPKC{delta} through regulating synaptic elements of presynaptic acetylcholine (Ach) release and postsynaptic nicotinic acetylcholine receptors (nAChRs). Methamphetamine (METH) withdrawal anxiety and METH-primed reinstatement of conditioned place preference (CPP) recruit eLPBChAT-lCeAPKC{delta} pathway and eLPBChAT-ovBNSTPKC{delta} pathway in male METH-exposed mice, respectively.

neuroscience↗

Expanding the Evo-Devo Toolkit: Generation of 3D mammary tissue from diverse mammals

The divergent events during mammary gland development between species and across evolution are not well studied mainly due to the lack of tractable model systems. In theory, advancements in the field of organoid technology now make it possible to study developmental processes adapted throughout species evolutions to accommodate advantageous phenotypes. However, its application to the mammary gland remains limited to rodents and humans. In the current study, we successfully created next-generation 3D mammary gland organoids from eight eutherian mammals and the first 3D organoid of a marsupial mammary gland (the gray short-tailed opossum), representing a more ancient version of the mammary gland. Using mammary organoids, we identified a role for ROCK protein in regulating branching morphogenesis, a role that manifests differently in human and opossum mammary organoids. This finding demonstrates the utility of 3D organoid model for understanding the evolution and adaptations of signaling pathways. Overall, the establishment of mammary organoids as animal model surrogates is a significant advancement in the field of mammary gland biology and evolution and paves the way for future studies utilizing this model. This achievement highlights the potential of organoid models to expand our understanding of mammary gland biology and evolution and their utility in studying milk production and breast cancer research.

developmental biology↗

Discrete projections from MCH neurons mediate anti-parkinsonian effects of acupuncture

Parkinsons disease (PD) presents with typical motor dysfunction and non-motor symptoms, including memory loss. Although acupuncture is suggested as an alternative therapy for PD, its neuroanatomical mechanisms remain unclear. We demonstrate that acupuncture ameliorates both motor and memory deficits in PD mice through activation of melanin-concentrating hormone (MCH) neurons in the lateral hypothalamus and zona incerta (LH/ZI)--MCHLH/ZI-- via nerve conduction. We identify two distinct subpopulations of MCHLH/ZI projecting to the substantia nigra and hippocampus, each of which is responsible for controlling motor and memory function. This effect can be attributed to MCH-mediated recovery from dopaminergic neurodegeneration, reactive gliosis, and impaired hippocampal synaptic plasticity. Collectively, MCHLH/ZI constitutes not only the neuroanatomical basis of acupuncture but also a potential cellular target for treating both motor and non-motor PD symptoms. One-Sentence SummaryAcupuncture alleviates both motor and non-motor symptoms in Parkinsons disease by activating two distinct MCH projections.

neuroscience↗

De novo fatty-acid synthesis protects invariant NKT cells from cell death, thereby promoting their homeostasis and pathogenic roles in airway hyperresponsiveness

AbstractInvariant natural-killer T (iNKT) cells play pathogenic roles in allergic asthma in murine models and possibly also humans. While many studies show that the development and functions of innate and adaptive immune cells depend on their metabolic state, the evidence for this in iNKT cells is very limited. It is also not clear whether such metabolic regulation of iNKT cells could participate in their pathogenic activities in asthma. Here, we showed that acetyl-coA-carboxylase 1 (ACC1)-mediated de novo fatty-acid synthesis is required for the survival of iNKT cells and their deleterious functions in allergic asthma. ACC1, which is a key fatty-acid synthesis enzyme, was highly expressed by lung iNKT cells from WT mice that were developing asthma. Cd4-CreAcc1fl/fl mice failed to develop OVA-induced and HDM-induced asthma. Moreover, iNKT cell-deficient mice that were reconstituted with ACC1-deficient iNKT cells failed to develop asthma, unlike when WT iNKT cells were transferred. ACC1 deficiency in iNKT cells associated with reduced expression of fatty acid-binding proteins (FABPs) and peroxisome proliferator-activated receptor (PPAR){gamma}, but increased glycolytic capacity that promoted iNKT-cell death. Furthermore, circulating iNKT cells from allergic-asthma patients expressed higher ACC1 and PPARG levels than the corresponding cells from non-allergic-asthma patients and healthy individuals. Thus, de novo fatty-acid synthesis prevents iNKT-cell death via an ACC1-FABP-PPAR{gamma} axis, which contributes to their homeostasis and their pathogenic roles in allergic asthma.

immunology↗

Electro-acupuncture alleviates ACE-increased anxiety-like behaviors in mice of adulthood by targeting claustrum D1R CaMKII

Adolescent cocaine exposure (ACE) increases risk of developing psychiatric problems such as anxiety, which may drive relapse in later life, however, its underlying molecular mechanism remains poorly understood. Methods: ACE male mice model were established by exposing to cocaine during adolescent period. Elevated plus maze (EPM) were used to assess anxiety-like behaviors in mice. Within claustrum, local injection of SCH-23390, a specific antagonist for dopamine receptor 1 (D1R), or D1R knocking-down virus were used to regulate D1R function or expression on CaMKII-positive neurons (D1RCaMKII) in vivo. Electro-acupuncture (EA) treatment was performed at acupoints of Baihui and Yintang during withdrawal period. Results: We found that ACE mice exhibited anxiety-like behaviors, along with more activated CaMKII-positive neurons and increased D1RCaMKII levels in claustrum during adulthood. Inhibiting D1R function or knocking-down D1RCaMKII levels in claustrum efficiently reduced claustrum activation, and ultimately suppressed anxiety-like behaviors in ACE mice during adulthood. EA treatment alleviated ACE-evoked claustrum activation and anxiety-like behaviors by suppressing claustrum D1RCaMKII. Conclusion: Our findings identified a novel role of claustrum in ACE-induced anxiety-like behaviors, and put new insight into the D1RCaMKII in the claustrum. The claustrum D1RCaMKII might be a promising pharmacological target, such as EA treatment, to treat drugs-induced anxiety-like behaviors. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/512685v5_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1b22744org.highwire.dtl.DTLVardef@12fed83org.highwire.dtl.DTLVardef@1924caforg.highwire.dtl.DTLVardef@1e896ca_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

Indoxyl Sulfate, a Uremic Toxin, Induces Trained Immunity of Monocytes through the AhR-Dependent Arachidonic Acid Pathway

Trained immunity is the long-term functional reprogramming of innate immune cells, which results in altered responses toward a secondary challenge. Despite indoxyl sulfate (IS) being a potent stimulus associated with chronic kidney disease (CKD)-related inflammation, its impact on trained immunity has not been explored. Here, we demonstrate that IS induces trained immunity in monocytes via epigenetic and metabolic reprogramming, resulting in augmented cytokine production. Mechanistically, the aryl hydrocarbon receptor (AhR) contributes to IS-trained immunity by enhancing the expression of arachidonic acid (AA) metabolism-related genes such as Arachidonate 5-Lipoxygenase (ALOX5) and ALOX5 Activating Protein (ALOX5AP). Inhibition of AhR during IS training suppresses the induction of IS-trained immunity. Monocytes from end-stage renal disease (ESRD) patients have increased ALOX5 expression and after 6-day training, they exhibit enhanced TNF- and IL-6 production to LPS. Furthermore, healthy control-derived monocytes trained with uremic sera from ESRD patients exhibit increased production of TNF- and IL-6. Consistently, IS-trained mice and their splenic myeloid cells had increased production of TNF- after in vivo and ex vivo LPS stimulation compared to that of control mice. These results provide insight into the role of IS in the induction of trained immunity, which is critical during inflammatory immune responses in CKD patients.

immunology↗