International Immunopharmacology

BackgroundShort-chain fatty acids (SCFAs) are produced by the gut microbiota as secondary metabolites during fermentation process of dietary fibers. Although SCFAs are beneficial for immuno-related diseases because they regulate the gene expression and functions of myeloid cells, the effects of SCFAs on the development of DCs remain unclear. MethodsWe analyzed the effect of SCFAs on the expression levels of surface proteins and mRNAs, and histone modification in Flt3L-induced bone marrow-derived DCs. ResultsSCFAs, particularly butyrate, regulated the expression of surface molecules on mouse bone marrow-derived dendritic cells (DCs): increases in MHCII, CD86, CD11b, and LPAM-1 (4{beta}7) levels and the ratio of CD11c+/PDCA-1-/B220- conventional DCs (cDCs) to CD11c+/PDCA-1+/B220+ plasmacytoid DCs (pDCs). Experiments using inhibitors of histone deacetylase (HDAC) and Gi proteins, and GPR109A deficient mice indicated that butyrate regulated DCs by suppression of HDACs and not through a stimulatory effect on G protein-coupled receptors. Butyrate and the HDAC inhibitor, trichostatin A (TSA), increased the cDC/pDC ratio, surface LPAM-1 and Itga4 mRNA, while the mRNA level of Itgb7 was not affected by butyrate and was reduced by TSA. ChIP assays showed that butyrate and TSA increased histone acetylation in the Itga4 and Spi1 genes. Furthermore, the butyrate treatment increased the levels of Spi1 mRNA and PU.1 protein and decreased those of Spib/SpiB in DCs. In knockdown (KD) experiments using siRNAs, the gene expression of Itga4 was decreased by KD of Spi1 or Irf8, and cDC/pDC ratio decreased by Spi1 KD. ConclusionsButyrate controls the gene expression and development of DCs through epigenetic regulation and DC-related transcription factors.

Preterm infants are acutely susceptible to neonatal sepsis, a syndrome characterized by systemic pro-inflammatory activity and life-threatening multi-organ dysfunction. However, the specific pulmonary pathological response to sepsis and the potential for metabolic interventions to mitigate lung injury remain poorly characterized. Herein, we evaluated the impact of varying parenteral glucose regimens on pulmonary outcomes during severe infection using a preterm piglet model. Genome-wide gene expression analysis was used to characterize lung transcriptome profiles. The relationships between gene expression and circulating biochemical and immune profiles were also investigated. Our findings demonstrate that significant pulmonary tissue damage is a hallmark of neonatal sepsis. A reduced-glucose regimen markedly attenuated pulmonary tissue damage while simultaneously alleviating systemic metabolic acidosis and hyperlactatemia. Mechanistically, lung transcriptome profiling revealed a profound activation of pathways associated with inflammatory signaling, programmed cell death, and the dysregulation of glucose, amino acid, and lipid metabolism. The low-glucose intervention effectively mitigated these widespread molecular and metabolic disturbances, suggesting a restorative effect on the pulmonary transcriptome landscape. To facilitate further mechanistic exploration and the identification of novel therapeutic targets, we developed the NeoSepPulmoExplorer (https://pharmaco-omicslab.shinyapps.io/NeoSepPulmoExplorer/), an interactive web-based toolkit for better mechanistic understanding and the identification of potential treatment targets. These results collectively underscore the importance of metabolic modulation in preserving organ function, though further translational studies are requisite to improve clinical outcomes in septic neonates.

AimsPercutaneous coronary intervention has improved survival following myocardial infarction, yet strategies to further reduce infarct size are limited. This study investigates the role of cytotoxic {gamma}{delta}-T cells in ischemic cardiomyocyte death and potential therapeutic interventions to reduce infarct size. MethodsGenetic and pharmacological approaches were used to delete {gamma}{delta}-T cells and their specific proteins to assess their involvement in cardiomyocyte death using mouse models of permanent ligation (PL) and ischemia/reperfusion (IR). Results{gamma}{delta}-T cells accumulated in infarct zones within 6h post-PL, expressing IFN-{gamma}, TNF-, granzyme B, and perforin. Their deletion reduced infarct size by 73% (PL) and 64% (IR). They induced cardiomyocyte death via apoptosis, gasdermin E-dependent pyroptosis, and MLKL-dependent necroptosis; {gamma}{delta}-T cell depletion reduced apoptosis by 80% and pyroptosis by 38%, with perforin deletion yielding similar effects. Necroptosis, attributed to combined IFN-{gamma}/TNF- cytotoxicity, decreased by 67%. Cytoplasmic DNA (cDNA) in stressed cardiomyocytes activated the cGAS/STING pathway, inducing expression of chemoattractant MCP-1 and death signal RAE-1. These signals recruited and activated {gamma}{delta}-T cells, which then triggered the death of the stressed cardiomyocytes. STING inhibition suppressed these expressions, reducing {gamma}{delta}-T cell accumulation and infarct size. NKG2D-deficient {gamma}{delta}-T cells prevented activation and reduced infarct size. Administration of an anti-IFNAR antibody at PL onset markedly reduced infarct size. ConclusionEarly activation of cytotoxic {gamma}{delta}-T cells via cardiomyocyte stress signals contributes significantly to immunogenic cardiomyocyte death. Targeting the STING pathway and type I interferon signalling presents a promising therapeutic avenue to mitigate infarct size and improve outcomes.

Abstract Background: Mean platelet volume (MPV) is a simple, low-cost biomarker that reflects platelet activation. Its prognostic value in septic shock remains controversial. We aimed to determine whether MPV at intensive care unit (ICU) admission is associated with hospital mortality in patients with septic shock. Methods: Retrospective cohort study of consecutive adults with septic shock (Sepsis-3 criteria) admitted to a single ICU. MPV, severity scores (SOFA, APACHE II, SAPS II), procalcitonin, and clinical data were collected. The primary outcome was in-hospital mortality. Spearman correlation, univariate and multivariate logistic regression (with Firth's correction), ROC curves, and subgroup analyses were performed. Results: Fifty-eight patients were included; mortality was 58.6%. MPV did not differ between non-survivors and survivors (13.09 {+/-} 1.37 vs. 12.66 {+/-} 1.45 fL, p = 0.259). MPV showed a weak correlation with procalcitonin ({rho} = 0.394, p = 0.002) but not with severity scores. In multivariate analysis adjusting for age, sex, SOFA and comorbidity count, MPV was not an independent predictor of mortality (OR 1.075, 95% CI 0.682-1.755, p = 0.749). The area under the ROC curve for MPV was 0.598 (95% CI 0.444-0.752), significantly lower than that of SOFA (0.837) and procalcitonin (0.836). Subgroup analyses showed no significant association between MPV and mortality in any stratum. Conclusions: In this cohort of septic shock patients, MPV at ICU admission was not associated with hospital mortality and had poor discriminative ability. Widely used severity scores and procalcitonin remain superior prognostic markers. MPV should not be used as a prognostic tool in septic shock. Keywords: Septic shock, Mean platelet volume, Mortality, SOFA, Procalcitonin, Biomarker

Mechanisms that promote organ injury after trauma and hemorrhagic shock (T/HS) remain poorly defined. Endothelial heparan sulfates with a 3-O-sulfate (3-OS) modification, controlled by the HS3ST1 gene, have anticoagulant and anti-inflammatory properties through their interaction with antithrombin. Our objective was to determine whether HS3ST1 deficiency drives organ injury and poor outcomes after T/HS. Hs3st1-/- and wild-type (WT) mice were subjected to T/HS followed by resuscitation with lactated ringers (LR) or fresh frozen plasma (FFP). While no differences were observed between WT and Hs3st1-/- LR resuscitated mice, lung injury and leukocyte infiltrates were significantly increased in FFP resuscitated Hs3st1-/-compared to WT mice. In vitro, leukocyte slow rolling and adherence was increased in HS3ST1 KO compared to WT cells. Among 472 T/HS patients, of which 31 (7%) were homozygous for the rs16881446 variant allele (GG), the number of ventilator free days was lower, and mortality was significantly higher in AG and GG patients. The rs16881446 genotype was independently associated with mortality. In conclusion, HS3ST1 deficiency mitigates organ protection from FFP resuscitation, partly through mediating EC:leukocyte engagement, and predicts mortality after T/HS. These findings identify a novel therapeutic target and prognostic tool that can be leveraged towards improved risk stratification after trauma.

BackgroundNeonatal sepsis is a major cause of morbidity and mortality, particularly in low- and middle-income countries such as Senegal, where incidence is 78-104 per 1,000 live births and mortality exceeds 20 per 1,000, with case fatality rates around 36%. Diagnosis is difficult due to non-specific clinical signs and lack of molecular biomarkers, highlighting the need for improved early diagnostic molecular markers that could be applied even outside of hospital settings. ObjectivesCompare neonatal and adult serum proteomes to establish a reference and identify serum protein biomarkers of neonatal sepsis. MethodsSerum samples from Senegalese neonates and adults were analyzed using data-independent acquisition (DIA) proteomics on neat serum (Evosep-timsTOF HT platform). The cohort comprised 6 neonates with non-confirmed sepsis (NCS), 22 with confirmed sepsis (CS), 17 healthy newborn controls (HC), 6 unclassified and 20 healthy adults. Downstream analyses included differential protein abundance testing, unsupervised clustering, weighted gene co-expression network analysis (WGCNA), and correlation analyses with clinical parameters. ResultsWe identified 979{+/-}20 proteins in newborns versus 718{+/-}40 in adults. Newborns showed reduced immune-response proteins, a narrower dynamic range, and increased structural proteins such as collagens, consistent with immune immaturity and tissue development. Unsupervised WGCNA analysis led to a 53-protein cluster discriminated CS from NCS/HC. Some of these dysregulated proteins identified have already been reported in independent studies using different approaches in neonatal and/or adult sepsis. Our larger panel however of identified markers maps to three major biological processes involved in sepsis: (i) pathogen sensing (LBP, CD14), and acute-phase inflammation (e.g. CRP, SAA1/2, ORM1/2); (ii) innate immune activation and leukocyte recruitment (e.g., FCGR3A, CSF1R, CD163, CD206) and final platelet exhaustion and metabolic dysregulation, (e.g., PF4, PPBP, THBS1, GP5); (iii) endothelial injury and microvascular dysfunction with tissue remodeling (e.g., ICAM1, VCAM1, VWF, SPARC) and loss of protective lipoproteins and serpins (e.g., APOA1, APOA2, APOM, SERPINA4, SERPINA5) ConclusionThis study provides a very comprehensive neonatal serum proteome characterization and identifies, for the first time, a protein panel of proteins mapped to three major processes in sepsis.

Cyclooxygenase-1 (COX-1) is classically regarded as a constitutive enzyme that produces eicosanoids with housekeeping functions, but recent evidence indicates that it may also be involved in the acute phase of severe systemic inflammation. There is evidence indicating that COX-1 is selectively activated in the spleen via post-translational mechanisms early the course of LPS-induced systemic inflammation. However, the mechanistic link between COX-1 and the spleen has not yet been demonstrated in direct experiments. The present study was conducted to fill this gap. The effects of the COX-1 inhibitor SC-560 on the LPS-induced severity triad (hypotension, hypothermia and acidosis) were evaluated in rats subjected to splenectomy or in sham-operated controls. In the sham-operated group, SC-560 significantly attenuated the severity triad independently of changes in plasma cytokines (TNF and IL-1{beta}). In the splenectomized rats, SC-560 completely lost its ability to attenuate the hypotension and the acidosis induced by LPS. The effect of SC-560 on LPS-induced hypothermia was also impaired by splenectomy, though not completely. We then conducted a lipidomic screening to identify which COX-1-derived eicosanoids might be responsible for mediating the severity triad. Based on spleen-blood correlations, the screening identified PGE2 and PGD2 as putative candidates. In conclusion, the present study provides direct evidence for a mechanistic link between the spleen and COX-1 in the mediation of severity in systemic inflammation, and identifies PGE2 and PGD2 as putative candidates involved.

Gasdermins are a family of pore-forming proteins that regulate the release of pro-inflammatory cytokine, interleukin-1{beta} (IL-1{beta}) from infected or PAMP-stimulated cells. During infection or injury, IL-1{beta} is released by both human and mouse macrophages. IL-1{beta} release from mouse macrophages is associated with cell death, often termed "pyroptosis". Mouse macrophages undergoing pyroptosis assemble an exit channel termed gasdermin D (GSDMD). Both the processing of IL-1{beta} and the formation of the exit channel are caspase-1 dependent. Here, in bacterial endotoxin, lipopolysaccharide (LPS), treated mouse bone marrow-derived macrophages (BMDMs), we studied the pharmacologic inhibition of the intracellular nucleotide-binding domain, leucine-rich-containing family, pyrin domain- containing-3 (NLRP3) inflammasome by OLT1177. BMDMs stimulated with LPS plus the potassium efflux inducer nigericin triggered the formation of the NLRP3 inflammasome. Treatment of these BMDMs with OLT1177 suppressed cell death by 42% and ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain)-speck formation by approximately 60%. In addition, OLT1177 dose-dependently inhibited IL-1{beta}, CCL3, and myeloperoxidase (MPO) secretion and the pore-forming (GSDMD) from LPS-primed BMDMs, suggesting the existence of a vicious cycle controlled by IL-1{beta} release. Overall, our study demonstrates that OLT1177 prevents IL-1{beta} release from BMDMs by inhibiting caspase-1 and the conversion of (GSDMD) into its active N-terminal fragment (GSDMD-N). This study thus supports the concept that orally administered OLT1177 can be used to prevent local as well as systemic inflammation in humans.

Vaccine-induced immune responses are the result of an intricate interplay between different cell populations of the innate and adaptive immune system, which is so far only partly understood. In particular, the role of polymorphonuclear neutrophils (PMNs) has long been neglected. Here, we studied the effects of a whole inactivated virus influenza vaccine (WIV) in an in vitro system consisting of freshly isolated human PMNs alone or PMNs combined with autologous peripheral blood mononuclear cells (PBMCs). Isolated PMNs showed minimal responses to the vaccine with respect to apoptosis, gene expression, cytokine production, and reactive oxygen species production. However, in WIV-stimulated PMN/PBMC co-cultures, PMNs particularly enhanced monocyte dynamics, CD14-CD11c+ cell activation, effector T cell differentiation, and B cell antibody production. On the other hand, PMNs decreased T follicular helper cell frequencies. Without vaccine stimulation, PMN presence resulted in enhanced levels of baseline inflammatory cytokines in PMN/PBMC co-cultures. However, with vaccine stimulation, PMNs dampened the vaccine-induced cytokine secretion of PBMCs. These findings reveal PMNs as regulators of vaccine responses whose effects depend on crosstalk with other immune cells, balancing pro-inflammatory and adaptive immune activation. Author summaryPolymorphonuclear neutrophils (PMNs) are essential and predominant cells of the human innate immune system. Growing evidence implicates that PMNs are involved in vaccine-induced immune activation, but their exact role is so far poorly defined. In our study, human PMNs were tested alone to observe their response to whole inactivated virus influenza vaccine (WIV), or combined with autologous peripheral blood mononuclear cells (PBMCs) to investigate how their presence influences vaccine responses of various cell populations within PBMCs. Our results show that WIV had little direct effect on isolated PMNs. However, when PMNs were combined with other immune cells, PMNs acted as crucial regulators: they enhanced the activity of innate immune cells, regulated the responses to the vaccine of T and B cells, and helped control the overall level of inflammation. Our study forms the groundwork for a more comprehensive understanding of human immune cell interactions under vaccine stimulation.

The success of Chimeric Antigen Receptor (CAR) T cell therapy is heavily dependent on the quality of the final cellular product. Current expansion protocols often rely on reagents that require removal from cell culture media, posing logistical challenges in manufacturing, and can also lead to terminal differentiation. Here, we evaluate the use of a soluble, bead-free T cell activator, T cell expansion protein (T-CEP), as a streamlined alternative for generating potent CAR-T cells. Human T cells were activated with T-CEP or known T cell activators (Dynabeads and TransAct) and transduced with either CD19 or interleukin-13 (IL-13) mutein (tetravariant-13; TV-13)-based CAR lentiviral vectors. Our results demonstrate that T-CEP supports robust CAR-T cell expansion and achieves transduction efficiencies comparable to commercial reagents for both types of CAR-T cells. Notably, T-CEP significantly favored the expansion of CD8+ T cells, yielding an enhanced CD27+ phenotype and a lower CD4:CD8 ratio compared to TransAct. Cytotoxicity assays confirmed that T-CEP-expanded CAR-T cells possess cytolytic function equivalent to commercial reagents for both CARs, while exhibiting lower levels of inflammatory cytokine secretion. In summary, T-CEP represents a competitive alternative to existing expansion agents, as it does not require its removal during CAR-T manufacturing and generates a CD8+ dominant, less-differentiated phenotype without compromising efficacy.

Background: Chronic and non-healing wounds remain a major clinical challenge with limited therapeutic options. Angiogenesis and inflammation are central to tissue repair, and mesenchymal stem cells (MSC) contribute to these processes through their trophic and immunomodulatory secretome. Cannabidiol (CBD) exhibits antioxidant and immunomodulatory properties. However, whether CBD-rich Cannabis sativa extract stimulate MSC toward a pro-angiogenic secretome remains unclear. Purpose: This study aims to determine whether purified CBD or a phytochemically CBD-rich full spectrum extract stimulate umbilical cord-derived human MSC (UC-hMSC) to secrete pro-angiogenic factors and enhance endothelial responses relevant to wound healing. Methods: UC-hMSC were preconditioned with either purified CBD or a CBD-rich full-spectrum extract. Transcriptional changes were assessed by qPCR. The functional impact of the resulting secretome was evaluated in vitro using HUVEC-based proliferation and tube formation assays, and in vivo through the chick chorioallantoic membrane assay. To explore underlying mechanisms, we examined HIF-1 stabilization and VEGFA release in UC-hMSC, and VEGFR-2/ERK signaling in HUVEC. Results: Purified CBD and full-spectrum CBD extract preconditioned UC-hMSC secretomes, increased HUVEC proliferation, tube formation, and enhanced vascular branching in the CAM assay. Mechanistic analyses indicated activation of the HIF-1/VEGF axis in UC-hMSC, and ERK1/2 activation in HUVEC that was sensitive to VEGFR-2 blockade. Conclusion: Purified CBD and CBD-rich full-spectrum extract prime UC-hMSC toward a pro-angiogenic secretome that promotes endothelial activation and neovascularization. These findings suggest that cannabinoid-based preconditioning of UC-hMSC involves the HIF-1/VEGF axis and VEGFR-2/ERK signaling pathways in endothelial cells, supporting further investigation of this approach in wound healing and regenerative therapies.

Thymosin {beta}4 (T{beta}4) is a conserved acidic polypeptide with 43-amino acids participating in multiple pathophysiological processes. In this study in vivo effects of T{beta}4 on liver regeneration are investigated in carbon-tetrachloride (CCL4) induced rodent animal liver jury models. Results illustrate that exogenous T{beta}4 treatment significantly reduced CCL4-rendered liver necrosis around central vein. At 48 hours after CCL4 insults hepatocytes proliferation occur mainly around the periportal area, while hepatocytes proliferation around the necrosis area is prominently increased by exogenous T{beta}4 treatment. The holistic proliferation level of liver tissues are also enhanced by exogenous T{beta}4. Hepatocyte proliferation activities negatively correlate with the necrosis extent of the liver tissue. These results suggested firstly exogenous T{beta}4 treatment could enhance liver regeneration and exhibit prosperous potential for application in clinical conditions such as liver transplantation.

Objectives; The role of nuclear receptor subfamily 4, group A, member 3 (NR4A3) in hepatic steatosis, inflammation, and insulin resistance (IR) within the context of metabolic dysfunction-associated steatotic liver disease (MASLD) remains largely underexplored. Consequently, this study aimed to examine NR4A3's impact on MASLD and the potential underlying mechanisms. Methods; We aimed to elucidate the functional role of NR4A3 in MASLD through its knockdown in cell culture and animal models. To establish the cell culture model of MASLD, LO2 cells were treated with free fatty acids (FFAs), while male C57BL/6 mice were fed a high-fat diet (HFD) to create the animal model. NR4A3 knockdown was achieved using specific short hairpin RNA (NR4A3-shRNA) in the mice model and three small interfering RNAs (NR4A3-siRNAs) in the cell culture model. The lipids content, fatty acid synthesis, inflammatory factors, and IR were then assessed with and without NR4A3 knockdown. Furthermore, the underlying mechanism through which NR4A3 exerts its influence was explored by analyzing the interaction between NR4A3 and activating transcription factor 3 (ATF3). Results: In the cell culture experiments, the knockdown of NR4A3 significantly decreased the lipids content, fatty acid synthesis, and inflammatory factors in the LO2 cells treated with FFAs in the NR4A3-shRNA group compared with those in the NC-shRNA control group. In the animal model experiments, NR4A3 knockdown in the HFD male C57BL/6 mice significantly ameliorated HFD-induced hepatic steatosis, inflammation, and IR. Mechanistically, the knockdown of NR4A3 downregulated the expression and transcriptional activity of ATF3, resulting in an impaired ATF3 function. ATF3 overexpression significantly reversed lipid accumulation decline and reduced inflammation after NR4A3 knockdown. Conclusion: The downregulation of NR4A3 alleviates MASLD by modulating ATF3, suggesting this may be a promising therapeutic target.

BACKGROUNDAtherosclerotic cardiovascular disease remains the leading cause of death worldwide. Most current pharmacotherapies target conventional risk factors that promote atherosclerosis (e.g., hyperlipidemia) rather than intrinsic resilience factors that protect against atherosclerosis in the face of risk factors. Here, we investigated the role of desert hedgehog (DHH), a canonical ligand of the hedgehog signaling pathway, as a novel resilience factor that restrains endothelial mesenchymal transition (EndoMT) and protects against atherosclerosis. METHODSSingle-cell RNA sequencing (scRNA-seq) was performed on atheroprone and atheroprotective regions of the ApoE knockout mouse aorta to identify mechanoresponsive genes associated with atherosclerosis. Endothelial cell-specific Dhh knockout mice were subjected to partial carotid ligation and hypercholesterolemic conditions to investigate the role of endothelial Dhh in atherosclerosis progression. scRNA-seq, bulk RNA sequencing, endothelial lineage tracing, immunoprecipitation-coupled mass spectrometry, and surface plasmon resonance were used to in-vestigate the role and mechanism of DHH in EndoMT. Pharmacological interventions and recombinant DHH administration were performed in vivo to evaluate therapeutic potential of DHH targeting. DHH expression was also examined in human atherosclerotic arteries and serum samples from patients with coronary artery disease. RESULTSDHH protein expression was enriched in arterial endothelium from mice, porcine, and humans. However, DHH expression was significantly reduced in atherosclerotic arteries and serum from patients with coronary artery disease. scRNA-seq of atheroprone and atheroresistant region of mouse aorta identified Dhh as a novel mechanoresponsive gene enriched in aortic regions exposed to unidirectional laminar flow. Endothelial cell-specific Dhh knockout (DhhecKO) mice exhibited increased atherosclerotic lesion area, large necrotic cores, and reduced collagen content following partial carotid ligation. Similarly, under hypercholesterolemic conditions, both male and female DhhecKO mice showed aggravated atherosclerosis progression. scRNA-seq of DhhecKO mouse aortas revealed an increased proportion of endothelial cells undergoing mesenchymal transition, indicating enhanced EndoMT. These findings were corroborated by bulk RNA-sequencing of DHH depleted HUVECs and endothelial lineage tracing in inducible DhhecKO mice. Mechanistically, DHH directly interacted with plasminogen activator inhibitor type 1 (PAI-1) and suppressed PAI-1-induced EndoMT. PAI-1 promoted EndoMT in ECs through activation of canonical TGF-{beta} signaling (SMAD2/3) and noncanonical AKT/ERK1/2 signaling via interaction with low-density lipoprotein receptor-related protein (LRP1). Neutralization of PAI-1 or inhibition of LRP1, AKT/ERK1/2, or SMAD3 signaling abolished DHH deficiency-induced EndoMT. DHH competitively inhibited PAI-1 binding to LRP1, thereby attenuating downstream pro-EndoMT signaling. Intriguingly, treatment with PAI-1 inhibitor TM5275 mitigated endothelial Dhh deficiency induced EndoMT in vivo. Of translational relevance, recombinant mouse DHH protein administration reduced atherosclerosis progression, stabilized plaque, and decreased the expression of EndoMT markers in ApoE knockout mice. CONCLUSIONSDesert hedgehog (DHH) is an intrinsic endothelial cell-enriched resilience factor that protects against EndoMT and atherosclerosis by preventing PAI-1 signaling. The present study implicates endothelial DHH as a potential therapeutic target for atherosclerotic cardiovascular disease. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=163 SRC="FIGDIR/small/729715v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@fc4d4forg.highwire.dtl.DTLVardef@37a3feorg.highwire.dtl.DTLVardef@efb761org.highwire.dtl.DTLVardef@1f06feb_HPS_FORMAT_FIGEXP M_FIG C_FIG Desert hedgehog (DHH) is an intrinsic endothelial cell-enriched resilience factor that protects against EndoMT and atherosclerosis by preventing PAI-1 binding to LRP1 and downstream AKT/ERK, as well as SMAD2/3 signaling. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABSO_LIDHH was identified as a flow-responsive resilience gene that is downregulated by disturbed flow in endothelial cells. C_LIO_LIEndothelial-specific deletion of Dhh promoted endothelial-to-mesenchymal transition (En-doMT) and atherosclerosis. C_LIO_LIDHH directly interacts with PAI-1 and preclude PAI-1 mediated pro-EndoMT signaling. C_LI What Are the Clinical Implications?O_LIDHH maintains endothelial homeostasis during atherosclerosis. C_LIO_LITargeting endothelial DHH-PAI-1 axis may represent a potential therapeutic strategy to reduce EndoMT and limit plaque progression. C_LIO_LILower circulating DHH level may serve as a potential biomarker of endothelial dysfunction and plaque vulnerability in atherosclerotic disease. C_LI

BACKGROUND: Perfluorooctane sulfonate (PFOS) is a widely distributed persistent organic pollutant in the environment and has been associated with an increased risk of atherosclerosis. However, the underlying pathogenic mechanisms remain largely unclear. This study aimed to investigate the effects of PFOS on atherosclerosis and its associated gut-vascular axis. METHODS: Pseudo-germ-free mouse models and fecal microbiota transplantation (FMT) were used to determine the role of the gut microbiota in PFOS-induced atherosclerosis. Metagenomic sequencing was performed to characterize alterations in gut microbial composition following PFOS exposure, and targeted metabolomics was used to assess bile acid profiles in the ileum and plasma. Transcriptomic analysis of Bacteroides caecimuris (B.caecimuris) was conducted to explore the reasons for the increased abundance of B.caecimuris after PFOS exposure. In addition, intestinal transcriptomics and ChIP-qPCR were performed to validate transcriptional regulation within the FXR-TLR3 signaling axis. RESULTS: Among 127 participants with paired serum and fecal samples, including 82 patients undergoing coronary angiography with Gensini scores (GS score), fecal PFOS levels were significantly associated with lipid profiles and GS score, whereas serum PFOS showed no such association. Mechanistically, PFOS exposure promotes intestinal enrichment of B. caecimuris by upregulating its tolC gene, thereby enhancing efflux capacity. This microbial shift was accompanied by reduced levels of tauro-ursodeoxycholic acid (TUDCA) and aberrant activation of intestinal FXR signaling. Further analyses demonstrated that FXR activation upregulated TLR3 expression and promoted inflammatory responses and atherosclerosis progression via the TLR3-NF-{kappa}B signaling axis. Both intestinal epithelial-specific FXR deficiency (Fxr{Delta}IE) and TUDCA supplementation significantly suppressed pathway activation and alleviated disease phenotypes.Functional experiments identified TLR3 as a key downstream effector of FXR. Overexpression of TLR3 abolished the protective effects observed in Fxr{Delta}IE mice. Moreover, pharmacological inhibition of TLR3 using CU CPT-4a significantly improved established atherosclerotic lesions in vivo. CONCLUSIONS: This study identifies a gut microbiota-driven FXR-TLR3 signaling axis that mediates PFOS-induced atherosclerosis. These findings provide new mechanistic insights into environmentally induced cardiovascular disease and suggest potential targets for risk assessment and therapeutic intervention.

Spinal cord injury (SCI) is a devastating neurological condition with limited regenerative capacity. Stem cell-based approaches have emerged as promising strategies due to their neuroprotective and immunomodulatory properties, largely mediated by small extracellular vesicles (sEVs) and their molecular cargo, including miRNAs. In this study, we aimed to evaluate the neuroprotective and anti-apoptotic potential of sEVs derived from SPC-01 and iMR-90 neural stem cell sources using an in vitro rat model of SCI. sEVs were isolated from conditioned media and characterized by multi-angle dynamic light scattering and Western blot analysis. Organotypic spinal cord slices (SCS) were used as an in vitro SCI model, with injury induced at 18-20 days, followed by immediate sEV application. After 72 h, tissue samples were collected and tissue was analyzed for markers of apoptosis, cytoskeletal integrity, and survival-related signaling pathways. Results show that SCI induced cytoskeletal disruption and increased apoptotic markers. Treatment with sEVs mitigated these changes, reducing injury-associated protein levels toward baseline. Both SPC-01- and iMR-90-derived sEVs exerted comparable neuroprotective effects, accompanied by decreased PTEN expression, enhanced STAT3 phosphorylation, and increased levels of the anti-apoptotic protein Bcl-xL. In parallel, reduced Nogo-A expression and normalization of RhoA suggested improved cytoskeletal stability and attenuation of inhibitory signaling. Together, these findings demonstrate that neural stem cell-derived sEVs promote early neuroprotective responses in vitro by modulating key signaling pathways, reducing apoptosis, and stabilizing cytoskeletal dynamics, supporting their potential as a cell-free therapeutic strategy for SCI.

BackgroundAtherosclerosis is a chronic inflammatory vascular disorder with persistent residual inflammation even after standard lipid-lowering therapy. Mounting evidence from bench to bedside suggests that diabetes and obesity accelerate atherosclerosis development. Tirzepatide (TZP), a dual Glucagon-Like Peptide-1 Receptor/Glucose-Dependent Insulinotropic Polypeptide Receptor (GLP-1R/GIPR) agonist approved for treating diabetes and obesity, has demonstrated proven cardiometabolic efficacy in large cardiovascular outcome trials. However, it remains largely uncertain whether TZP attenuates atherosclerosis independent of its anti-diabetic and anti-obese effects through direct actions on the vasculature. MethodsWe established atherosclerotic mouse models under diabetic, obese, and non-diabetic/non-obese conditions. Analysis of covariance (ANCOVA) and pair-feeding experiments were applied to experimentally decouple weight-dependent metabolic improvement from intrinsic vasculoprotection. Molecular and cell biological assays in human umbilical vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs) were performed to dissect the underlying signaling mechanisms. ResultsTZP markedly reduced aortic plaque burden and inflammation, restrained necrotic core enlargement, and improved plaque stability across all experimental mouse models. Both ANCOVA and pair-feeding experiments confirmed that these atheroprotective effects were independent of food intake and body weight loss. Furthermore, TZP attenuated systemic and vascular inflammation in Tumor Necrosis Factor- (TNF)-treated C57BL/6J mice, and this protection occurred without changes in body weight or blood glucose levels. Mechanistically, TZP directly targeted endothelial cells and activated the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/endothelial nitric oxide synthase (eNOS) pathway, increased eNOS phosphorylation and nitric oxide bioavailability, consequently downregulating the expression of the pro-inflammatory adhesion molecules Vascular Cell Adhesion Molecule-1 (VCAM-1) and Intercellular Adhesion Molecule-1 (ICAM-1). ConclusionsTZP arrests atherosclerosis progression through weight loss-independent anti-inflammatory mechanisms. These findings implicate TZP as a promising therapeutic drug for mitigating residual vascular inflammation in patients with atherosclerotic cardiovascular disease (ASCVD), irrespective of glycemic status or obesity. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABSO_LITirzepatide exerts direct anti-atherosclerotic effects in preclinical mouse models of atherosclerosis under diabetic, obese, and non-obese conditions. C_LIO_LITirzepatide directly targets endothelial GLP-1R/GIPR and downstream cAMP/PKA/eNOS signaling pathway to suppress NF-{kappa}B-driven vascular inflammation, thereby uncovering a previously unrecognized vasculoprotective mechanism underlying its cardiovascular benefits C_LI What Are the Clinical Implications?O_LITirzepatide exerts direct vascular protective effects independent of body weight reduction, suggesting that its cardiovascular benefits may extend beyond glycemic control and obesity management. C_LIO_LITirzepatide may represent a promising therapeutic drug for addressing residual vascular inflammation in ASCVD patients, including those without overt diabetes or obesity C_LI

Type 1 diabetes (T1D) is caused by T cell-mediated autoimmune destruction of insulin-producing islet beta-cells. Treatment with T-cell depleting therapies delays the progression of stage 2 and 3 T1D, but these agents exert broad immunosuppressive effects on T cell populations, including T regulatory cells (Tregs), which are key in promoting immune tolerance. We evaluated non-obese diabetic (NOD) mice and recently diagnosed T1D patients and identified CD38 as a marker for pathogenic T cell populations. Using adoptive T-cell transfer in Recombination Activating Gene 1 knockout NOD mice and in a humanized mouse model of autoimmune diabetes, we demonstrated that CD38-expressing autoreactive T cells drive diabetes pathogenesis. Furthermore, we found that selective depletion of CD38+ cells, using an anti-CD38 monoclonal antibody (mAb), prevents insulitis and diabetes onset without depleting CD4+CD25+ Tregs. Administration of anti-CD38 mAb did not adversely affect islet function and may selectively eliminate immunogenic senescent islet beta-cells. These results support the strategy of selectively depleting diabetogenic T cells using an anti-CD38 mAb to treat T1D and restore immune tolerance. Therefore, transient depletion of autoreactive T cells using anti-CD38 mAb may provide a novel strategy to prevent or abrogate autoimmunity in T1D.

BackgroundSuccinate has emerged as an immunometabolic mediator of cardiovascular diseases. However, the enzymatic mechanisms linking macrophage succinate metabolism to aortic dissection remain incompletely understood. This study investigated whether Suclg2, which encodes the GDP-forming {beta}-subunit of succinyl-CoA ligase, regulates succinate-associated macrophage remodelling and aortic dissection progression. MethodsSuclg2 expression was examined in BAPN-induced AD and human acute type A aortic dissection tissues by Western Blot and immunofluorescence. Myeloid- and smooth muscle cell-specific Suclg2 conditional knockout mice were subjected to BAPN treatment to evaluate survival, aortic outcomes, histological injury and aortic morphology. Aortic RNA-seq was used to discover transcriptional changes. Bone marrow-derived macrophages were analysed under basal, M1-like and M2-like conditions to assess macrophage-intrinsic transcriptional responses. Plasma succinate levels and untargeted metabolomic profiles were further examined. ResultsSuclg2 was increased in murine and human dissected aortas and partially localized to CD68 cells. Myeloid Suclg2 deletion markedly reduced BAPN-induced aortic rupture and dissection, whereas smooth muscle cell Suclg2 deletion did not confer comparable protection. Aortic transcriptomic analysis showed that myeloid Suclg2 deficiency attenuated inflammatory adhesion and matrix-destructive programmes. In macrophages, Suclg2 deletion did not induce a simple M1/M2 polarization shift; instead, it remodelled lipid-handling, phagolysosomal, adhesive and matrix-remodelling pathways across stimulation states. Metabolic profiling showed reduced circulating succinate and broader changes in central carbon, lipid-associated, nucleotide and redox-related metabolites after myeloid Suclg2 deletion. ConclusionsMyeloid Suclg2 is a succinate-associated immunometabolic regulator of aortic dissection. Its deficiency protects against aortic dissection by reshaping macrophage inflammatory-remodelling programmes and the systemic metabolic environment.

BACKGROUNDSmooth muscle cells (SMCs) comprise the majority of cells in human atherosclerotic lesions and are thought to be a major source of cholesterol-overloaded foam cells in human and mouse atheromas. However, the transcriptomic profile, specific markers, and biologic itinerary of SMC foam cells relative to macrophage foam cells remain poorly defined. METHODSSingle-cell RNA sequencing (scRNA-seq) was performed on fresh coronary artery segments from heart transplant recipients with early- to intermediate-stage atherosclerosis. Gene expression in a putative SMC foam cell cluster was compared with cultured SMCs loaded with aggregated low-density lipoprotein (agLDL) or cholesterol-methyl-{beta}-cyclodextrin (Chol-M{beta}CD). Candidate markers distinguishing SMC from macrophage foam cells were validated using additional publicly-available scRNA-seq datasets, Xenium spatial transcriptomics, and immunofluorescence microscopy of human coronary atheromas. Pathway analysis was performed using Gene Set Enrichment Analysis Hallmark gene sets. RESULTSA distinct SMC foam cell cluster derived from fibromyocytes ("lipomyocytes") was identified using markers induced by in vitro cholesterol loading. agLDL loading reproduced the lipomyocyte transcriptional profile, whereas Chol-M{beta}CD induced an inflammatory phenotype colocalizing with macrophages rather than lipomyocytes. Lipomyocytes highly expressed SERPINE1, encoding plasminogen activator inhibitor-1 (PAI-1), and CFH, encoding complement factor H, which were validated in human coronary lesions by spatial transcriptomics and immunofluorescence microscopy. Compared with macrophage foam cells, lipomyocytes demonstrated distinct pathway activation, including enrichment of extracellular matrix, coagulation and angiogenesis pathways. CONCLUSIONSSMC foam cells, or lipomyocytes, represent a distinct foam cell phenotype with unique markers and biologic programs that differ from macrophage foam cells during atherosclerotic plaque development. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABSO_LISmooth muscle cell (SMC) foam cells, or lipomyocytes, arise from fibromyocytes and exhibit a transcriptomic profile that is markedly distinct from that of macrophage foam cells. C_LIO_LIIn vitro loading of SMCs with aggregated LDL recapitulates the gene expression profile of SMC foam cells in human coronary atheromas, whereas loading with cyclodextrin-bound cholesterol does not. C_LIO_LIPlasminogen activator inhibitor 1 (PAI-1, encoded by SERPINE1) and Complement Factor H are specific markers of SMC foam cells and are not expressed by macrophage foam cells. C_LI What Are the Clinical Implications?O_LISMCs contribute a substantial proportion, and potentially the majority, of foam cells in atherosclerotic lesions. C_LIO_LIDefining the biological trajectory of SMC foam cells within plaques is critical for understanding their roles in plaque progression, rupture and thrombosis, and for establishing their relevance as a distinct therapeutic target to reduce major cardiovascular events. C_LI