TLR4–MyD88–NF-κB Signaling in the Airway Epithelium Promotes <i>Acinetobacter baumannii</i> Clearance

The Journal of Infectious Diseases · 2026-01-31

BACKGROUND: Acinetobacter baumannii is a high-priority Gram-negative respiratory pathogen associated with high morbidity and mortality. While many components of the innate immune response to A. baumannii have been studied, the specific role of the airway epithelium in coordinating the innate immune response to A. baumannii is largely undefined. In this study we demonstrate that NF-κB signaling within airway epithelial cells is essential for effective pulmonary clearance of A. baumannii. METHODS: To understand the role of epithelial signaling, we utilized several mouse models of infection. RESULTS: Using both pharmacological and conditional knockouts of the NF-κB subunit RelA (p65) in airway epithelial cells of mice, we observed substantial defects in bacterial clearance from the airways and lungs. This impaired clearance was associated with significant reductions in early neutrophil recruitment to the airway, which was linked to decreased expression of key neutrophil chemokines (G-CSF, GM-CSF, and CCL20) at both the transcript and protein levels. RNA sequencing of sorted airway epithelial cells revealed that NF-κB activity was required for transcription of inflammatory and chemotactic genes. Administration of exogenous neutrophil chemokines was able to restore early neutrophil recruitment in epithelial RelA-deficient mice, but only partially rescued bacterial clearance, suggesting additional mechanisms beyond granulocyte chemokine induction. We also show that airway epithelial expression of TLR4 and its adaptor protein MyD88 are also required for effective bacterial clearance from the airway, identifying a TLR4-MyD88-NF-κB axis. CONCLUSIONS: These findings highlight the airway epithelium as a critical site of innate immune sensing and coordinating the pulmonary host defense against A. baumannii.

Development and Internal Validation of a Pretransplant Biomarker Panel for Mortality Prediction Following Liver Transplant

JAMA Surgery · 2026-02-11 · 2 citations

Importance: Current pretransplant clinical scoring systems fail to accurately estimate post-liver transplant (LT) survival, making recipient selection challenging. Persistent immune dysfunction contributes to early LT recipient mortality but is not captured by existing models. Objective: To identify plasma biomarkers of pretransplant immune dysfunction and to develop a biomarker-based pre-LT risk stratification tool to predict post-LT mortality. Design, Setting, and Participants: Prospective biomarker analysis of consecutively enrolled adult LT recipients was conducted. Healthy controls were included for baseline comparison. Patients undergoing LT at Houston Methodist Hospital (October 1, 2013, to December 31, 2017) and Rutgers/University Hospital (January 1, 2019, to March 31, 2021) were enrolled under an institutional review board-approved protocol, and data were censored on March 31, 2023, and analyzed. Patients with cirrhosis older than 18 years undergoing deceased donor LT were included. Exclusion criteria were age greater than 70 years, cancer other than hepatocellular carcinoma, retransplant, status 1A, intraoperative mortality, multivisceral transplant (except liver-kidney), and sample availability. Exposures: Plasma cytokine, chemokine, and immune exhaustion biomarkers were quantified using multiplex Luminex assays at the time of transplant. Clinical, demographic, and laboratory data were extracted from institutional databases. Main Outcomes and Measures: The primary outcome was all-cause mortality within 1 year of LT. Secondary outcomes included graft survival, infections, rejection, readmissions, and 24-month survival. Results: A total of 779 adult LTs were performed between 2007 and 2017, with prospective biomarker analysis of 279 consecutively enrolled LT recipients between 2018 and 2022. Median (IQR) participant age was 56.7 (48.2-62.5) years, and 110 of 279 patients (39.4%) were female. Pre-LT plasma levels of B-cell activating factor, C-C motif chemokine ligand 1, eotaxin, fractalkine, interleukin 1β (IL-1β), sIL-6Rβ, metalloproteinase (MMP) 2, and MMP3 were significantly associated with 1-year post-LT mortality. Multivariable Cox proportional hazards modeling identified fractalkine and MMP3 as independent predictors of early post-LT mortality. These were used to develop the Liver Immune Frailty Index (LIFI), stratifying patients into low, moderate, and high risk. One-year mortality was 1.9%, 10.3%, and 63.6% for LIFI-low, -moderate, and -high, respectively. Relative risk of death within 1 year was 5.43 (95% CI, 1.59-18.60; P < .001) for LIFI-moderate and 33.41 (95% CI, 11.48-97.25; P < .001) for LIFI-high compared to LIFI-low. LIFI demonstrated strong discrimination (C statistic, 0.83) and was associated with post-LT infections, longer hospital stays, and reduced patient survival. Conclusions and Relevance: Per the results of this diagnostic/prognostic study, LIFI identifies LT candidates with severe immune dysfunction at high risk for early post-LT mortality, offering a preoperative, objective tool to refine transplant candidacy, guide perioperative management, and improve LT outcomes.

Initial Analysis of Plant Soil for Evidence of Pathogens Associated with a Disease of Seedling <i>Ocotea monteverdensis</i>.

PubMed · 2025-07-17

best predicted the patterns of the different N metrics in the soils, supporting their possible roles in this disease.

Transcriptional profiling defines unique subtypes of transit amplifying neural progenitors within the neonatal mouse subventricular zone

bioRxiv (Cold Spring Harbor Laboratory) · 2025-08-21 · 1 citations

While significant progress has been made in understanding the heterogeneity in the NSCs, our understanding of similar heterogeneity among the more abundant transit amplifying progenitors is lagging. Our work on the NPs of the neonatal subventricular zone (SVZ) began over a decade ago, when we used antibodies to the 4 antigens, Lex CD133,LeX,CD140a and NG2 and FACs to classify subsets of the neontal SVZ as either multi-potential (MP1, MP2, MP3, MP4 and PFMPs), glial-restricted (GRP1, GRP2, and GRP3), or neuron-astrocyte restricted (BNAP). Using RNAseq we have characterized the distinctive molecular fingerprint of 4 SVZ neural progenitors and compared their gene expression profiles to those of the NSCs. Overall, we identified 1581 genes that were upregulated in at least one NP compared to the NSCs. Of these genes, 796 genes were upregulated in BNAP/GRP1 compared to NSCs; 653 in GRP2/MP3; 440 in GRP3; 527 in PFMPs. One gene in particular that emerged from our analysis that can be used to distinguish the NPs from the NSCs is Etv1, also known as Er81. Interestingly, PFMPs expressed high levels of the transcription factor GSX1, which has been shown to play important roles in regulating interneuron development in the forebrain. PFMPs are also highly express PDGFRα, CSPG4 (NG2+) Olig2 and transcripts for olfactory receptors. PFMPs also express Sox10, Gjb1, Zfp488 and Myt1 which have been shown to be important for oligodendrocyte development. The top transcription factors with unique upregulation in BNAP/GRP1s were Zfp57, Hoxac6, and Zfp955a. Unlike the other NPs, the GRP1 and GRP2 NPs expressed many proteins involved in immune cell function. In contrast, the top downregulated genes in the NPs are those involved in cilia formation, consistent with the loss of cilia as neural stem cells become multipotential progenitors. We performed bionformatic analyses to provide insights into the transcription factor interactions that are likely regulating their development as well as the functional consequences of these diffferences in gene expression. The present work will serve as an important resource for investigators interested in further defining the transit amplifying progenitors of the mammalian SVZ.

Dynamic expression of endometrial adhesion G protein-coupled receptors during the menstrual cycle and early mouse pregnancy: modulation by ovarian stimulation

F&S Science · 2025-05-16 · 2 citations

OBJECTIVE: To characterize the expression of adhesion G protein-coupled receptors (ADGR) in the human endometrium and early mouse pregnancy. DESIGN: An in silico analysis was performed using a retrospective data set comprised endometrial samples across normo-ovulatory menstrual cycles. Gene expression was then validated using quantitative reverse transcription polymerase chain reaction and mRNA sequencing (mRNA-seq) in prospectively collected endometrial biopsies in the periovulatory and midsecretory stages of natural cycles. Gene expression was also investigated under ovarian stimulation (OS) conditions using mRNA-seq. Early pregnancy mouse models were used to investigate whether trends of dynamic ADGR expression are also conserved in the mouse. SUBJECTS: Twenty-four women aged 21-42 years. EXPOSURE: Ovulatory menstrual cycle or OS cycle. MAIN OUTCOME MEASURES: Gene expression in endometrial biopsies and pregnant mouse uterus. RESULTS: Fifteen women, aged 21-33 years, were recruited in natural cycles during the proliferative phase (cycle days 10-13; n = 4), periovulatory (luteinizing hormone + 12-24 hours; n = 6) period, and midsecretory (luteinizing hormone + 8-9 days; n = 5) phase. Nine women aged 31-42 years old undergoing in vitro fertilization (without fresh embryo transfer) or oocyte cryopreservation using a gonadotropin releasing hormone antagonist protocol were recruited for the OS cohort in either the periovulatory phase (human chorionic gonadotropin + 2; n = 5) or midsecretory phase (human chorionic gonadotropin + 9; n = 4). The in silico analysis revealed dynamic expression for many ADGRs across the menstrual cycle. Differential gene expression was also seen in the prospective analysis within the menstrual cycle phases and between natural cycle and OS conditions. Within early mouse pregnancy, expression was also found to be altered across several Adgr subfamilies. CONCLUSION: The differential gene expression observed between the proliferative and secretory phases of the menstrual cycle, along with changes in expression seen in OS and early mouse pregnancy suggest that ADGR expression is hormonally regulated by estradiol and progesterone.

Dysregulated of monocyte function prior to liver transplant is associated with increased risk of post-transplant mortality 3930

The Journal of Immunology · 2025-11-01

Abstract Description Cirrhosis induces progressively severe immune dysfunction, which persists early after liver transplant (LT) and increases risk of morbidity and mortality both prior to and following LT. We have previously identified the Liver Immune Frailty Index (LIFI), a pre-LT biomarker panel (MMP-3 and Fractalkine), which stratifies patients into tertiles of risk for post-LT mortality. 1-yr post-LT mortality is 63% vs. 1.8% in LIFI-high and -low (c-statistic 0.83). Plasma and PBMCs were obtained at the time of liver transplant (T0) and stratified by LIFI (-low vs high/moderate). Bulk RNAseq demonstrates distinct gene expression profiles in LIFI-high/moderate vs LIFI-low. Notably, pathways related to toll-like receptors (TLRs) signaling and phagocytic activity were enriched, indicating innate immune involvement in pre-LT immune dysfunction. Single-cell RNAseq analysis of monocyte clusters identified CD14+ monocytes as major contributors to TLRs and pattern recognition receptors (PRRs) upregulation in T0 PBMCs. These changes could result from bacterial translocation due to cirrhosis-related increases in intestinal permeability and peripheral vasodilation prior to LT. Such increases in antigen presentation could trigger an excessive pro-inflammatory response by monocytes. Persistence of such monocyte dysregulation early after LT could contributing to ongoing immune dysfunction and increased susceptibility to infection, thus impacting risk of post-LT mortality. Funding Sources 1R01DK137222-01A1, 1R21AI180739-01A1 Topic Categories Transplantation Immunology (TRAN)

Initial Analysis of Plant Soil for Preliminary Characterization of the Possible Etiology of Disease of Seedling from &lt;em&gt;Ocotea monteverdensis&lt;/em&gt;

Preprints.org · 2025-06-23

Seedlings of the ecologically important and “critically endangered” tree, Ocotea monteverdensisis, are experiencing high mortality in the cloud forests of Monteverde, Costa Rica at the onset of the wet season, yet no previous work has been conducted to determine the disease etiology. Here, healthy and diseased Plant Root and adjacent Bulk soils were analyzed for total organic carbon and nitrogen (N), respiration, nitrate, and ammonium, and DNA sequence-based bacterial and fungal community composition. All N metric levels were greater in Diseased vs. Healthy Plant Root soils, which could enhance pathogen growth and pathogenic mechanisms. Greater DNA percentages from several potential pathogens were found in Diseased vs. Healthy Plant Root soils, suggesting a root pathogen etiology. The DNA percentage of the fungus Mycosphaerella was present at greater levels in the Diseased Plant Root soils than other potential pathogens (about 11.7% vs. &amp;lt; 3.2%). Mycosphaerella causes similar diseases in other plants, including coffee, often after onset of the wet season. Similarly, the O. monteverdensis disease occurs in seedlings planted within or near former coffee plantations often at wet season onset. Although fungal pure culture isolation and transmission studies are needed, this is the first evidence of a potential etiologic agent of this disease.

Dysregulation of Pre-Transplant Monocyte Function is Associated with Increased Risk of Mortality Following Liver Transplant

American Journal of Transplantation · 2025-08-01

Transcriptional Profiling Defines Unique Subtypes of Transit Amplifying Neural Progenitors Within the Neonatal Mouse Subventricular Zone

Biomolecules · 2025-10-11 · 1 citations

While significant progress has been made in understanding the heterogeneity of Neural Stem Cells (NSCs), our understanding of similar heterogeneity among the more abundant transit amplifying progenitors is lagging. Our work on the neural progenitors (NPs) of the neonatal subventricular zone (SVZ) began over a decade ago, when we used antibodies to the four antigens, CD133, LeX, CD140a, and NG2 to perform Fluorescence-activated cell sorting to classify subsets of the neonatal mouse SVZ as either multi-potential (MP1, MP2, MP3, MP4 and PFMPs), glial-restricted (GRP1, GRP2, and GRP3), or neuron-astrocyte restricted (BNAP). Using RNA sequencing, we have characterized the distinctive molecular fingerprints of four SVZ neural progenitor subtypes and compared their gene expression profiles to those of the NSCs. We performed bioinformatic analyses to provide insights into each NP type’s unique interactome and the transcription factors regulating their development. Overall, we identified 1581 genes upregulated in at least one NP subset compared to the NSCs. Of these genes, 796 genes were upregulated in BNAP/GRP1 compared to NSCs; 653 in GRP2/MP3; 440 in GRP3; and 527 in PFMPs. One gene that emerged from our analysis that can be used to distinguish the NPs from the NSCs is Etv1, also known as Er81. Also notable is that the NSCs downregulated cilia formation genes as they differentiated to become multipotential progenitors. Among the NPs, both PFMP and GRP3 subtypes differentially expressed genes related to neuron and oligodendrocyte development, including Matn4, Lhfpl3 and Olig2. GRP3s uniquely expressed Etv5, a transcription factor known to promote glial cell fate specification, while PFMPs uniquely expressed Lhx6, a transcription factor that regulates interneuron specification. PFMPs also expressed transcripts for olfactory receptors. Unlike the other NPs, the GRP1 and GRP2 NPs upregulated expression of genes for proteins involved in immune function. The present work will serve as an important resource for investigators interested in further defining the transit amplifying progenitors of the mammalian SVZ.

MerTK is Cleaved From Alveolar Macrophages Following Exposure to Ozone

American Journal of Respiratory and Critical Care Medicine · 2025-05-01

Abstract Rationale: Ozone is a ubiquitous air pollutant associated with acute respiratory distress syndrome (ARDS). Mechanisms underlying this association have not been fully elucidated. ARDS is characterized by impairment of macrophage phagocytosis of apoptotic cells (efferocytosis). We previously found that exposure to ozone reduced resident alveolar macrophage (AM) efferocytosis of apoptotic neutrophils in the lungs of mice during sepsis; mechanisms underlying this reduction are unclear. MerTK is a macrophage surface receptor that mediates efferocytosis of apoptotic cells through activation of RHO-GTPase signaling. Evidence suggests that cleavage of MerTK from the surface of macrophages decreases the availability of functional efferocytosis receptors. Thus, we hypothesized that MerTK is cleaved from AMs following exposure to ozone and that this can be detected in mouse and human lung lining fluid. Methods: For mouse exposures, male C57Bl/6J mice were exposed to 0.8 ppm ozone or filtered air in a whole-body exposure chamber for 3 h and treated with i.v. LPS 24 h later. The next day mice were euthanized, and lung cells and fluid collected by bronchoalveolar lavage (BAL). Eight healthy male and female subjects were exposed to ozone (200 ppb) and filtered air for 3 h in a cross-over design and had sputum collected 48 h later. Cleaved, MerTK (cMerTK) was detected in cell-free BAL by western blot, and cell-free sputum supernatant by immunoprecipitation followed by western blot. RHO-GTPase signaling in mice was analyzed using single-cell RNA sequencing of BAL cells. Results: Exposure to ozone + PBS or ozone + LPS but not air + LPS increased cMerTK levels in the BAL relative to air + PBS exposed mice (median fold change=1.6, 1.8, 0.8, respectively; p&amp;lt;0.05). Principle component analysis of single-cell RNA sequencing followed by Ingenuity Pathway Analysis revealed a subset of AMs with reduced RHO-GTPase signaling in ozone + PBS and ozone + LPS but not air + LPS exposed mice, further suggesting MerTK dysfunction. Paired analysis of human sputum supernatants following air and ozone exposures revealed increased cMerTK levels in the lung following ozone exposure (median integrated density (arbitrary units) =448276 vs 752054, p=.008). Conclusion: These results demonstrate for the first time that exposure to ozone cleaves MerTK from AMs, providing a potential mechanism for ozone-induced efferocytosis impairment in the lung. Detection of increased cMerTK in human sputum following controlled ozone exposure suggests this mechanism may be relevant to human pathology and contribute to the increased risk of ARDS following exposure to ozone.