Biology subjects

Xia, L.

Publications and source records attributed to Xia, L..

At least 19 recordsLinked to original sources

bioRxiv2026

TEAD1 signaling modulates adrenal chromaffin maturation

Chromaffin cells synthesize and secrete catecholamines to coordinate systemic stress responses and regulate diverse neuroendocrine and metabolic functions. However, the molecular mechanisms governing chromaffin-cell differentiation and their disruption in pheochromocytoma (PC) remain incompletely understood. Here, through integrated analyses of human developmental atlases, patient-derived transcriptomic datasets, genetically engineered mouse models, and chromaffin organoids, we identify TEAD1 signaling as a critical regulator of chromaffin-cell differentiation and function. In vivo studies using a chromaffin cell-specific TEAD1 overexpression mouse model demonstrated that suppression of TEAD signaling markedly compromises chromaffin-cell differentiation and endocrine function. Additionally, compared with other TEAD family members, TEAD1 transcriptional activities are readily affected by sequences near the binding motif. To identify therapeutically actionable regulators of TEAD1 signaling, we established a TEAD activity-based screening platform and identified the serotonin receptor HTR5A antagonist SB699551 as a potent modulator of chromaffin-cell state. SB699551 suppressed PC-cell proliferation in vivo, and remodeled catecholamines synthesis in primary human PC cells. Additionally, application of SB699551 to human PC tumor revealed a subpopulation of primary chromaffin cells sensitive to this compound. Mechanistically, CXXC5 and L1CAM were identified as downstream SB699551-TEAD1 signaling effectors mediating chromaffin-cell proliferation and differentiation. Overall, we demonstrate that TEAD1 signaling is a fundamental mechanism regulating chromaffin cell differentiation and that modulation of TEAD1 signaling via SB699551 offers a new area of investigation in chromaffin cell biology.

molecular biology↗

bioRxiv2026

Concurrent Stereotactic Body Radiation Therapy and KRAS Inhibition Synergistically Improve Pre-clinical Pancreatic Cancer Treatment

Pancreatic ductal adenocarcinoma (PDAC) is one of the most challenging cancers to treat due to the dismal survival rate, poor post-treatment outcome and profound resistance to a wide range of therapies. With mutant KRAS being a key driver, small molecule inhibitors targeting KRAS or pan-RAS (KRASi) have demonstrated exciting preclinical and early clinical anti-tumor efficacy, and the pan-RAS(ON) inhibitor daraxonrasib (RMC-6236) recently achieved Phase 3 clinically meaningful improvements in patient survival compared to chemotherapy. But resistance to RAS/KRAS inhibitor inevitably develops, which limits and compromises the treatment outcome. In this study, we investigated the combination of stereotactic body radiation therapy (SBRT) and KRAS inhibition (MRTX1133 and daraxonrasib) in the treatment of preclinical PDAC models. We found that this combination strategy synergistically suppresses PDAC cell growth in vitro and enhances tumor control while minimizing local recurrence in orthotopically implanted KPC (LSL-KrasG12D/+;Trp53R172H/+;Pdx1-Cre) murine PDAC tumors in vivo. As radiation therapy (RT) induces ferroptosis in multiple cancer types and mutant KRAS promotes various anti-ferroptotic mechanisms, we tested the role of ferroptosis in promoting tumor-control efficacy. Intriguingly, the addition of a ferroptosis inhibitor, liproxstatin-1, to the combination therapy significantly abrogated the in vivo synergism between SBRT and KRAS inhibition, suggesting that treatment-induced ferroptosis at least partially drives the synergistic efficacy of this combination strategy. Our study indicates that this SBRT-KRASi combination has the potential to overcome treatment resistance and improve outcomes in PDAC patients. These data directly support the design of a planned multi-center Phase 2 clinical trial with this combination strategy in locally advanced PDAC.

cancer biology↗

bioRxiv2026

MOTS-c Coordinates Inter-Organellar Proteostasis for Adaptation to Chronic Metabolic Stress

Mitochondrial communication coordinates adaptive responses across organelles to sustain cellular homeostasis, a network that declines with age and contributes to loss of proteostasis. Here, we identify MOTS-c, an exercise-induced mitochondrial-derived peptide (MDP) encoded within the 12S rRNA locus, as an inter-organellar arm of the mitochondrial stress response (MSR) that links mitochondrial signaling to endoplasmic reticulum (ER) proteostasis and enables adaptation to chronic stress. Using progressive stress media (PSM), a model of gradual and multifactorial metabolic stress, we show that MOTS-c enables adaptation through a biphasic program: acutely, a reversible, ATF4-independent suppression of protein synthesis; and chronically, an ATF6-biased ER unfolded protein response (UPRER) with tempered ATF4 engagement and coordinated metabolic remodeling. Whereas mitochondrial unfolded protein response (UPRmt) pathways have been extensively characterized in acute, genetic, and sustained models of mitochondrial perturbation, this work reveals how mitochondrial communication actively engages ER proteostasis during progressive and persistent metabolic stress. By expanding proteostatic capacity while tempering terminal stress signaling, MOTS-c enables cells to withstand chronic stress. Together, these findings define a MOTS-c-dependent arm of the MSR that integrates mitochondrial communication with ER proteostasis to promote chronic metabolic stress adaptation.

Cell Biology↗

bioRxiv2026

Development and Function of Ovarian Lymphatic Vasculature

Lymphatic vessels play essential roles in interstitial fluid clearance and immune cell trafficking. Recent studies have uncovered previously unrecognized, organ-specific functions of the lymphatic vasculature in the meninges, heart, kidney, and lungs. However, the development and physiological significance of the ovarian lymphatic network remain poorly defined. To address this gap, we performed high-resolution three-dimensional imaging of ovarian lymphatic vasculature in mice. Our results reveal that the ovarian lymphatic network comprises lymphatic capillaries and valve-containing pre-collectors and the ovarian lymphatic vasculature arises from pre-existing lymphatic vessels in the broad ligament starting at postnatal day 5. Furthermore, we demonstrate that the VEGF-C/VEGFR-3 signaling is essential for ovarian lymphatic development and Vegfr3 insufficiency impairs ovarian lymphangiogenesis, leading to fibrosis and premature ovarian aging. Together, these findings identify the lymphatic vasculature as a critical component of the ovarian microenvironment and establish a causal link between lymphatic insufficiency and accelerated ovarian aging.

developmental biology↗

bioRxiv2026

Revisiting CPUs for Protein Folding: Xeon-Based Acceleration of AlphaFold2

Protein structure prediction via AlphaFold2 has revolutionized drug discovery, yet its end-to-end execution remains computationally intensive. While GPUs are traditionally favored for deep learning, the AlphaFold2 algorithm consists of heterogeneous phases -- preprocessing with sparse database searches and model inference with low-arithmetic-intensity attention modules -- that present unique architectural challenges. In this work, we address these bottlenecks by introducing Open-Omics-AlphaFold2, a highly optimized implementation for Intel(R) Xeon(R) CPU. By leveraging the CPUs versatility in handling both sparse preprocessing algorithms and dense matrix operations via Intel Advanced Matrix Extensions (AMX), we accelerate the entire pipeline end-to-end. Our optimization strategy employs multi-level parallelism -- spanning multiprocessing, multi-threading, and vectorization -- alongside cacheaware tiling and operator fusion. Our results demonstrate that, on a Xeon CPU, Open-Omics-AlphaFold2 achieves 2 7.58 speedup for preprocessing and 19.8 29.2 speedup for model inference over baseline Deepmind-AlphaFold2. Moreover, for a proteome of 391 proteins, Open-Omics-AlphaFold2 running on a dual-socket Intel Xeon 6980P system achieves a remarkable 76% higher through-put over the state-of-the-art GPU-accelerated solution, FastFold, running on a single-socket Intel Xeon 6980P CPU with an NVIDIA H100 offioad. Code availabilityBaremetal: https://github.com/IntelLabs/open-omics-alphafold Containerized: https://github.com/IntelLabs/Open-Omics-Accelera tion-Framework/tree/main/pipelines/alphafold2-based-protein-folding

genomics↗

bioRxiv2025

The cloacal outgrowth orchestrates co-development of the bladder and umbilical arteries

The urinary bladder is an innovation of eutherian mammals to manage liquid wastes. However, bladder development and its embryonic function remain poorly understood. Here, we report that in both humans and mice the bladder emerges from the cloaca as the rostral outgrowth, which is flanked by the umbilical arteries. Arrest of the outgrowth, as seen in Shh-null mouse embryos, causes bladder agenesis and unexpected severe defect of the umbilical arteries, suggesting that the outgrowth epithelial signal Shh coordinates development of both the bladder and umbilical arteries. Wnt2 signaling molecule is restricted to the rostral outgrowth mesenchyme; and its expression is dramatically down-regulated in Shh-null mutants. Furthermore, Wnt2-null mutants develop small bladder and single umbilical artery defects. Findings here uncover an unexpected co-development mechanism of the bladder and umbilical arteries orchestrated by the cloacal outgrowth signals. The co-development paradigm offers a conceptual framework to understand evolution and development of the bladder. Significance StatementThe urinary bladder is found in the eutherian mammals but largely absent from other vertebrates. Innovation of the bladder has been viewed as a necessity to manage liquid metabolic wastes on dry land. In this study, we report that the bladder emerges from the rostral outgrowth of the cloaca. We also report an unexpected developmental link between the bladder and umbilical arteries and, demonstrate that their co-development is orchestrated by the outgrowth epithelial signal Shh and mesenchymal signal Wnt2. Findings here highlight a possibility that, in addition to managing metabolic wastes, normal bladder development is required for growth of mammalian embryos by supporting development of the umbilical arteries.

developmental biology↗

bioRxiv2025

Nanopore Sequencing Unveils Somatic Structural Variations as Biomarkers in Laryngeal squamous cell carcinoma Genomes

Laryngeal squamous cell carcinoma (LSCC) is an aggressive cancer with poor quality of life, largely due to the absence of reliable molecular biomarkers for early diagnosis and prognosis. While somatic structural variations (SVs) have been documented in LSCC, conventional short-read sequencing approaches are inherently limited in detecting of large-scale somatic SVs, which are critical to understanding tumorigenesis. Here, we presented SomaGauss-SV, a somatic SVs detection workflow leveraging nanopore long-read sequencing data. Benchmarking against five paired tumor cell line datasets showed SomaGauss-SV consistently achieves a balanced high precision and recall. SomaGauss-SV applied to 15 paired LSCC tumor-blood samples uncovered a comprehensive SVs landscape and a significant positive correlation between somatic deletion burden and smoking intensity. Furthermore, a high-frequency somatic simple repeat expansion was identified in 20/27 (74.1%) of LSCC patients, upregulating the expression of genes TP53BP2 and FBXO28 through spatial proximity. These findings underscore the potential of long-read sequencing and SomaGauss-SV in uncovering previously unexplored genomic rearrangements in LSCC, providing valuable resources for biomarker discovery.

bioinformatics↗

bioRxiv2025

Essential role of CFAP77-CCDC105-TEX43 subcomplex in connecting axonemal A and B tubules for mammalian sperm motility

The assembly and physiological function of cilia and flagella depend on the stable association of A and B tubules, which form axonemal microtubule doublets (DMTs). CFAP77 encodes a core outer junction (OJ) protein within DMTs that is conserved across species and cell types. However, whether and how CFAP77 mediates the connection of B tubules to A tubules of DMTs in mammalian cilia/flagella are unknown. In this study, Cfap77-KO mice were generated to reveal that CFAP77 is essential for sperm progressive motility and male fertility. Loss of CFAP77 led to opened B tubules specifically at the OJ regions of axonemal DMTs as revealed by conventional transmission electron microscopy. Cryo-electron tomography further resolved the in situ structure of sperm axonemal DMTs from Cfap77-KO mice, which exhibited a loss of large filamentous density corresponding to the CFAP77-CCDC105-TEX43 ternary subcomplex at the OJ regions. Additionally, sperm proteomic analysis confirmed that CFAP77 knockout led to the complete loss of this ternary complex. Our work not only explores the physiological role of OJ protein CFAP77 on axonemal A-B tubule connection in mammals but also combines in situ structural biology and knockout mice to reveal the underlying structural/molecular mechanism.

cell biology↗

bioRxiv2025

Somatic repetitive element insertions Define New Biomarkers in Pan-cancer genome

Repetitive elements insertions (REIs), including tandem repeat insertions (TRIs) and transposable element insertions (TEIs), constitute >90% of large-scale (>50bp) somatic insertions and are linked to diseases and cancer biomarkers. However, the genomic landscape of large-scale REIs in pan-cancer has not been well-characterized due to short-read sequencing limitations. Here, we detected somatic REIs in 325 cancer genomes across 12 cancer types using long-read whole-genome sequencing and customized algorithms. The diverse sequence patterns of somatic TRIs and the insertion mechanisms of somatic TEIs were characterized across different cancer types. We identified 152 high-frequency somatic TRIs, with 10 showing pan-cancer characteristics, including TRIs in SHROOM2, PALMD, and the enhancer of PTPRZ1. The MHC class II gene cluster exhibited the highest somatic TEI abundance, affecting [~]40% tumors. Adenocarcinomas and squamous cell carcinomas exhibited differing TEI distributions within this region. Our study highlights REIs as important but under-explored markers for personalized cancer diagnosis and immunotherapy.

genomics↗

bioRxiv2025

Accurate Somatic SV detection via sequence graph model-based local pan-genome optimization

Somatic structural variations (SVs) are critical genomic alterations in cancer genomes. Long-read sequencing (LRS) is theoretically optimal for detecting somatic SVs. However, influenced by reads-to-reference alignment errors, particularly in low-complexity or highly repetitive genomic intervals, current LRS-based somatic SV callers fail to accurately detect SVs. Moreover, the lack of comprehensive ground-truth datasets hinders accurate evaluation. Here, we introduce SVscope, a novel algorithm that fundamentally addresses these challenges by leveraging full-length sequence information from span-reads and integrating local graph-genome optimization with a random forest strategy. SVscope outperforms state-of-the-art methods on six paired long-read whole-genome sequencing (WGS) benchmark cell lines, achieving a maximum F1-score improvement of 16.7%. In simulated datasets, SVscope demonstrates superior performance in both somatic SV detection and read phasing tasks. Based on the findings from SVscope, we validated 47 somatic SVs, thereby significantly expanding the existing experimentally validated ground-truth somatic SV dataset by 69.1%.

bioinformatics↗

bioRxiv2025

Lethal streptococcal infection is associated with widened lymph node bottlenecks

Streptococcus suis serotype 2 (SS2) infection causes streptococcal toxic shock-like syndrome (STSLS), which can be lethal in both pigs and humans. In mouse models, relatively subtle differences in the inoculum size result in drastically different infection outcomes, from clearance to acute death. Here, we leveraged barcoded SS2 in a murine model to define the bacterial population dynamics associated with death. Barcode sequencing analysis demonstrated that a 10-fold increase in inoculum size led to a 100-1,000-fold increase in the number of bacteria that initiated infection in certain lymph nodes, ultimately driving lethality. This lethal dose threshold was in part driven by suilysin (SLY), the major SS2 virulence factor. At higher doses, the clearance and replication kinetics of bacteria lacking SLY mimicked WT SS2 at sub-lethal doses. Our findings suggest that acute death in SS2 infection is caused by a wholesale failure of the immune system, enabling a large number of bacteria to initiate infection. These results demonstrate how subtle changes in inoculum size can have dramatic consequences for infection outcome and how lethal infection is driven by widened infection bottlenecks. Author SummaryLethal infections are often associated with a specific dose threshold, where increasing inoculum size is associated with an increased likelihood of death. However, a quantitative explanation how this numeric threshold is established is lacking. For example, lethal dose thresholds may reflect a dose where at least one microbe can pass through host-imposed barriers to infection. Alternatively, lethal dose thresholds may reflect a failure of the host immune system, leading to numerous microbes initiating infection. Here, using barcoded Streptococcus suis serotype 2 (SS2), we compare the within-host population dynamics associated between lethal and non-lethal infections. We find that lethal doses are associated with dramatic widening of infection bottlenecks, leading to a large number of bacteria that initiate infection. Lethal infection is also driven by suilysin, the major SS2 virulence factor. These observations demonstrate how lethal doses are quantitatively established by the relationship between host bottlenecks and bacterial virulence factors.

microbiology↗

bioRxiv2025

Molecular Insights into Cross-Species Spillover of Coronavirus HKU5 via ACE2 Receptor Recognition

Coronaviruses represent a significant zoonotic threat, with host adaptation serving as a pivotal determinant of cross-species transmission. The bat-derived {beta}-coronavirus HKU5 utilizes its spike (S) protein for receptor recognition and viral entry. Here, we report the cryo-electron microscopy (cryo-EM) structure of the HKU5 S protein in a closed conformation. Two fatty acids are found in each protomer of the HKU5 S protein, which stabilize the S protein in the closed conformation. Furthermore, we solve the structure of the HKU5 receptor-binding domain (RBD) in complex with the peptidase domain (PD) of Pipistrellus abramus angiotensin-converting enzyme 2 (ACE2), uncovering a unique binding mode distinct from other coronaviruses that use ACE2 as their receptor. Evolutionary and functional analyses indicate that mutations in the RBD can modulate receptor binding, while conservation and structural modeling suggest that HKU5 has the potential to cross the species barrier. Notably, we identify ACE2 orthologs in avian species, such as Pitta sordida, that support stable HKU5 RBD binding and interaction. Our functional assays, including pseudovirus entry and cell-cell fusion experiments, demonstrate that HKU5 can exploit ACE2 orthologs across species, providing molecular insights into its host adaptation and underscoring the importance of surveillance for this virus and its zoonotic risk.

biophysics↗

bioRxiv2024

S1PR1 Regulates Lymphatic Valve Development And Prevents Ileitis-Independent Tertiary Lymphoid Organ Formation

Lymphatic vessels function throughout the body to drain interstitial fluids. Efficient lymph flow is ensured by lymphatic valves (LVs). However, the mechanisms that regulate LV development are incompletely understood. Here, we show that the deletion of the GPCR sphingosine 1-phosphate receptor-1 (S1PR1) from lymphatic endothelial cells (LECs) results in fewer LVs. Interestingly, LVs that remained in the terminal-ileum draining lymphatic vessels were specifically dysfunctional, and tertiary lymphoid organs (TLOs) formed in this location. TLOs in the terminal ileum are associated with ileitis in humans and mice. However, mice lacking S1PR1 did not develop obvious characteristics of ileitis. Sphingosine kinases 1 and 2 (SPHK1/2) are required for the synthesis of S1P, the ligand of S1PR1. Mice that lack Sphk1/2 in LECs recapitulate the LV and TLO phenotypes of mice that lack S1PR1. Mechanistically, S1PR1 regulates shear stress signaling and the expression of the valve-regulatory molecules FOXC2 and connexin-37. Importantly, Foxc2+/- mice, a model for lymphedema-distichiasis syndrome, also develop TLOs in the terminal ileum. Thus, we have discovered S1PR1 as a previously unknown regulator of LV and TLO development. We also suggest that TLOs are a sign of subclinical inflammation that can form due to lymphatic disorders in the absence of ileitis.

developmental biology↗

bioRxiv2024

Single-Cell multiomics reveals ENL mutation perturbs kidney developmental trajectory by rewiring gene regulatory landscape

Cell differentiation during organogenesis relies on precise epigenetic and transcriptional control. Disruptions to this regulation can result in developmental abnormalities and malignancies, yet the underlying mechanisms are not well understood. Wilms tumors, a type of embryonal tumor closely linked to disrupted organogenesis, harbor mutations in epigenetic regulators in 30-50% of cases. However, the role of these regulators in kidney development and pathogenesis remains unexplored. By integrating mouse modeling, histological characterizations, and single-cell transcriptomics and chromatin accessibility profiling, we show that a Wilms tumor-associated mutation in the chromatin reader protein ENL disrupts kidney development trajectory by rewiring the gene regulatory landscape. Specifically, the mutant ENL promotes the commitment of nephron progenitors while simultaneously restricting their differentiation by dysregulating key transcription factor regulons, particularly the HOX clusters. It also induces the emergence of abnormal progenitor cells that lose their chromatin identity associated with kidney specification. Furthermore, the mutant ENL might modulate stroma-nephron interactions via paracrine Wnt signaling. These multifaceted effects caused by the mutation result in severe developmental defects in the kidney and early postnatal mortality in mice. Notably, transient inhibition of the histone acetylation binding activity of mutant ENL with a small molecule displaces transcriptional condensates formed by mutant ENL from target genes, abolishes its gene activation function, and restores developmental defects in mice. This work provides new insights into how mutations in epigenetic regulators can alter the gene regulatory landscape to disrupt kidney developmental programs at single-cell resolution in vivo. It also offers a proof-of-concept for the use of epigenetics-targeted agents to rectify developmental defects.

cancer biology↗

bioRxiv2024

Adolescent and adult mice use both incremental reinforcement learning and short term memory when learning concurrent stimulus-action associations

Computational modeling has revealed that human research participants use both rapid working memory (WM) and incremental reinforcement learning (RL) (RL+WM) to solve a simple instrumental learning task, relying on WM when the number of stimuli is small and supplementing with RL when the number of stimuli exceeds WM capacity. Inspired by this work, we examined which learning systems and strategies are used by adolescent and adult mice when they first acquire a conditional associative learning task. In a version of the human RL+WM task translated for rodents, mice were required to associate odor stimuli (from a set of 2 or 4 odors) with a left or right port to receive reward. Using logistic regression and computational models to analyze the first 200 trials per odor, we determined that mice used both incremental RL and stimulus-insensitive, one-back strategies to solve the task. While these one-back strategies may be a simple form of short-term or working memory, they did not approximate the boost to learning performance that has been observed in human participants using WM in a comparable task. Adolescent and adult mice also showed comparable performance, with no change in learning rate or softmax beta parameters with adolescent development and task experience. However, reliance on a one-back perseverative, win-stay strategy increased with development in males in both odor set sizes. Our findings advance a simple conditional associative learning task and new models to enable the isolation and quantification of reinforcement learning alongside other strategies mice use while learning to associate stimuli with rewards within a single behavioral session. These data and methods can inform and aid comparative study of reinforcement learning across species. Author summaryHere we studied the strategies and mechanisms mice use to learn a simple two choice odor based task in a single session. Using a set size manipulation and computational models we find evidence that mice use incremental reinforcement learning as well as several short-term (one-back) strategies to earn water reward. Our data and models clarify how mice learn a simple task and establish methods by which mouse and human reinforcement learning may be isolated for cross-species comparison of learning.

neuroscience↗

bioRxiv2024

Characterization of RNA editing profiles in rice endosperm development

Rice (Oryza sativa L.) endosperm provides nutrients for seed germination and determines grain yield. RNA editing, a post-transcriptional modification essential for plant development, unfortunately, is not fully characterized during rice endosperm development. Here, we conduct genome re-sequencing and RNA sequencing for rice endosperms across five successive developmental stages and perform systematic analyses to characterize RNA editing profiles during rice endosperm development. We find that the majority of their editing sites are C-to-U CDS-recoding in mitochondria, leading to increased hydrophobic amino acids, and affecting structures and functions of mitochondrial proteins. Comparative analysis of RNA editing profiles across the five developmental stages reveals that CDS-recoding sites present higher editing frequencies with lower variabilities, and recoded amino acids, particularly caused by these sites with higher editing frequencies, tend to exhibit stronger evolutionary conservation across many land plants. Based on these results, we further classify mitochondrial genes into three groups that present distinct patterns in terms of editing frequency and variability of CDS-recoding sites. Besides, we identify a series of P- and PLS-class pentatricopeptide repeat (PPR) proteins with editing potential and construct PPR-RNA binding profiles, yielding candidate PPR editing factors related to rice endosperm development. Taken together, our findings provide valuable insights for deciphering fundamental mechanisms of rice endosperm development underlying RNA editing machinery. Author summaryRice endosperm development, a critical process determining quality and yield of our mankinds essential food, is regulated by RNA editing that provokes RNA base alterations by protein factors. However, our understanding of this regulation is incomplete. Hence, we systematically characterize RNA editing profiles during rice endosperm development. We find that editing sites resulting in amino acid changes, called "CDS-recoding", predominate in mitochondria, leading to increased hydrophobic amino acids and affecting structures and functions of proteins. Comparative analysis of RNA editing profiles during rice endosperm development reveals that CDS-recoding sites present higher editing frequencies with lower variabilities. Furthermore, evolutionary conservation of recoded amino acids caused by these CDS-recoding sites is positively correlated with editing frequency across many land plants. We classify mitochondrial genes into three groups that present distinct patterns in terms of editing frequency and variability of CDS-recoding sites, indicating different effects of these genes on rice endosperm development. In addition, we identify candidate protein factors associated closely with RNA editing regulation. To sum up, our findings provide valuable insights for fully understanding the role of RNA editing during rice endosperm development.

bioinformatics↗

bioRxiv2023

Potential clinical value and influence of conductivity in conductive cardiac patches for reducing post-MI arrythmia risks

Conductive cardiac patches can help to restore electric signal conduction of the diseased myocardium after myocardial infarction (MI). However, none of the conductive cardiac patches reported in literature has entered clinical trials. Bench-to-bedside translation of conductive patches has long been hindered by the lack of knowledge of the optimal patch conductivity and deep understanding of the potential clinical benefits and risks in patients. Here, we first prepared conductive cardiac patches with conductivities covering 5 orders of magnitude (10-3-101 S/cm). Disagreeing with the mainstream opinion that patch conductivity close to native myocardium (10-3-10-2 S/cm) is most favorable, our results showed that patches with conductivity two orders of magnitudes higher than native myocardium (10-1-100 S/cm) are most effective in restoring cardiac conduction and lowering inducibility quotient. Conduction velocity (CV) is the essence of the observed results. Rat experiments showed that the low-conductivity patch could increase the CV of infarcted myocardium, but did not fully compensate the mismatch in the CVs of infarct and healthy myocardium. Moderate-conductivity patches could increase myocardial CV to the same level of healthy myocardium, while high-conductivity patches further increased myocardial CV, causing a reversed mismatch. The relationship between patch conductivity and improved CVs in myocardium can be explained by monodomain model theory. Based on the theory, 3D finite element simulation of a MI patient heart predicted that a suitable, patch-improved myocardial CV could reduce the number of reentrants, and stabilize the remaining reentry circuits in the myocardium of the MI patient, which indicated its clinical value.

bioengineering↗

bioRxiv2023

MIF Regulates M1 Macrophage Polarization via CD74/CXCR2/JNK Pathway and Mediates Aortic Dissection in Mice

BackgroundMacrophage polarization and vascular smooth muscle cell (VSMC) phenotypic switching are important features and critical targets in the progression of Aortic dissection (AD). High expression of macrophage migration inhibitory factor (MIF) in aortic and blood specimens has been observed in patients with aortic dissection, but its precise function and mechanism in AD are unknown. We aimed to clarify whether MIF mediates the development of aortic dissection via modulation of M1 macrophage polarization and its specific regulatory pathways. MethodsBased on the BAPN/Ang II-induced acute aortic dissection model and by intraperitoneal injection of the MIF antagonist ISO-1 to inhibit MIF activity in mice. We assayed macrophage infiltration, polarization, and VSMC phenotypic switching in the aorta of mice in each group. Further, we evaluated the polarizing effects of MIF on RAW264.7 cells directly or indirectly in vitro experiments and explored the specific cellular signaling pathways that mediate its function. At last, we evaluated the role and possible mechanisms of RAW264.7 cells with different degrees of polarization in inducing phenotypic switching of MOVAS cells based on a model of indirect co-culture of RAW264.7 cells with MOVAS cells. ResultsPharmacological inhibition of MIF decreased the incidence of BAPN/Ang II-induced aortic dissection and attenuated aortic vascular remodeling in mice by reducing M1 macrophage infiltration in mouse aorta. Through in vitro assays, we demonstrated that MIF could activate the intracellular JNK/c-Jun signaling pathway by targeting the CD74/CXCR2 receptor, promote M1 polarization and upregulate the expression of the M1 macrophage markers, iNOS, IL-18, and CD86 in RAW264.7 cells. Further experiments confirmed that upon co-culture with MIF-induced M1 macrophages, the NF-{kappa}B pathway was activated in MOVAS cells, inducing the onset of phenotypic switching and apoptosis. ConclusionsThe results indicated that MIF mediated macrophage polarization and regulated the progression of aortic dissection, which provided new scientific evidence for the pathogenesis of aortic dissection, and also suggested that MIF may be a potential preventive and therapeutic target for aortic dissection and aortic-related diseases.

molecular biology↗