Kawasaki disease (KD) is an acute febrile systemic vasculitis of unknown etiology and the leading cause of acquired heart disease among children. Complement activation has long been observed in patients with acute KD, however, its contribution to disease development remains unknown. Here, using publicly available datasets, we showed that patients with acute KD exhibited higher expression of complement products in whole blood, consistent with the activation of the complement pathway. Similarly, in the Lactobacillus casei cell wall extract (LCWE) murine model of KD, LCWE injection induced increased expression of complement products in cardiovascular tissues, suggestive of activation of the complement pathways. C3-deficient mice or WT mice treated with the complement C5a Receptor 1 (C5ar1) antagonist developed significantly more severe LCWE-induced cardiovascular lesions and vasculitis. Furthermore, we observed that LCWE binds to serum C3, an opsonizing factor that labels microbial targets for clearance, and LCWE deposition in the liver was significantly higher in C3-deficient mice compared to WT mice. Overall, our data indicate that blocking the complement system significantly exacerbates LCWE-induced KD vasculitis, likely by impairing C3-mediated clearance of LCWE. These data suggest that the complement pathway may play a protective role in KD pathogenesis by promoting clearance of potential bacterial or viral trigger of KD.

Malnutrition, gut inflammation, and antibiotic-induced dysbiosis are well-recognized risk factors for poor clinical outcomes among critically ill patients. We previously showed that commercially available plant-based enteral nutrition (PBEN) preserves a commensal microbiome compared with commonly used artificial enteral nutrition (AEN). In this study, PBEN was superior to AEN in promoting recovery from antibiotic-induced dysbiosis in mice and humans. PBEN effectively mitigated anemia and leukopenia, restored naive lymphocyte populations, and reduced bone marrow myeloid expansion. Animals randomized to PBEN also exhibited improved responses to infectious gastrointestinal challenges following antibiotic exposure. A pilot clinical study validated these findings, demonstrating increased gut commensals, reduced pathogens, and improved leukocyte balance in critically ill children receiving PBEN compared with AEN. Together, these results suggest that PBEN offers a practical dietary approach to mitigate antibiotic-associated complications and potentially improve clinical outcomes among hospitalized patients requiring supplemental nutrition.

Severity of aortic regurgitation correlates with atrial stretch and fibrillation. Uncovering stretch-mediated atrial remodeling prior to ventricular pathology will help define optimal timing of interventions.

Single-ventricle congenital heart disease (SV-CHD) is a uniformly lethal condition requiring the Glenn surgery, which as a side effect eliminates arterial pulsatility and contributes to pulmonary vascular complications. In Glenn patients, we quantified pulsatility loss in each dimension of force (flow, pressure, and stretch) using cardiac catheterization and MRI. To model and investigate the individual impact of each dimension of pulsatility loss on the pulmonary vasculature, we applied isolated pulsatile and non-pulsatile mechanical stimuli to pulmonary artery endothelial cells (ECs) in vitro. We found that each dimension of force triggered distinct transcriptional responses, revealing force-specific regulation of structural and signaling pathways. Pulsatile stretch uniquely stimulated EC secretion of PDGFB, a key driver of vascular smooth muscle cell (vSMC) recruitment. In a rat Glenn model, loss of pulsatility led to vascular wall thinning, loss of EC PDGFB, and reduced activation of smooth muscle PDGFBRβ, confirming in vivo relevance. Our findings uncover a mechanistic link between endothelial stretch sensing and PDGFB-mediated EC-vSMC crosstalk, essential for maintaining pulmonary artery architecture. Clinically, these insights suggest that restoring or mimicking pulsatile forces may help preserve vascular integrity and prevent remodeling in patients with SV-CHD.

Because older donor age is a major concern when considering kidneys for potential transplantation, we explored the actual impact of donor age on the features of kidneys that have been transplanted. We studied the correlations of donor age with molecular injury and rejection scores in 4502 kidney transplant biopsies assessed by microarrays, as well as function and postbiopsy survival. We used multivariable analyses to correct for the correlations of donor age with other predictive variables: recipient age, time of biopsy posttransplant, and deceased vs. living donors. Older donor age correlated with lower GFR and increased acute and chronic injury transcripts, but had no effect on rejection, which anti-correlated with recipient age. Acute injury transcripts peaked immediately posttransplant and regressed. Older donor age had little effect on acute molecular injury immediately posttransplant but strongly increased molecular injury scores at later times, peaking about 1-year posttransplant, indicating that older age does not increase molecular injury but increases failed repair post-injury. As expected, older donor age correlated with increased chronic injury and lower GFR, evident from the earliest time posttransplant, pre-transplant aging. However, despite significant age-related effects, the quantitative contribution of donor aging to molecular injury, function, and survival was very small.

Malaria caused by Plasmodium malariae is geographically widespread and sometimes associated with prolonged infection, yet little is known about its genomic epidemiology. We performed hybrid capture and whole genome sequencing of 77 isolates collected from Cameroon (n=7), the Democratic Republic of the Congo (n=16), Nigeria (n=4), and Tanzania (n=50) between 2015 and 2021, and analyzing parasite genetic population structure and demography. There is no evidence of geographic population structure. Nucleotide diversity was significantly lower than in co-localized P. falciparum isolates, while linkage disequilibrium was significantly higher. Genome-wide selection scans identified no erythrocyte invasion ligands or antimalarial resistance orthologs as top hits; however, targeted analyses of these loci revealed evidence of selective sweeps around four erythrocyte invasion ligands and six antimalarial resistance orthologs. Demographic inference modeling suggests that African P. malariae is recovering from a bottleneck. P. malariae is genomically atypical among human Plasmodium spp. and lacks strong population structure in Africa. The low diversity has potential impacts on understanding persistent versus new infection through genomic epidemiology.

In metabolic dysfunction-associated steatohepatitis (MASH), liver sinusoidal endothelial cells (LSECs) acquire a proinflammatory phenotype termed lipotoxic endotheliopathy. We previously identified glycogen synthase kinase 3β (GSK3β) as a central signaling hub in LSECs during MASH. To elucidate the molecular mechanisms and functional outcome of lipotoxicity-induced GSK3β activation in LSECs, we utilized endothelial cell-specific Gsk3β knockout (Gsk3β△End) mice fed MASH-inducing diets. Endothelial Gsk3β deletion significantly reduced markers of lipotoxic endotheliopathy, including adhesion molecules and chemokines, alongside liver injury, inflammation, and fibrosis. Immune profiling via flow cytometry and mass cytometry by time of flight (CyTOF) identified decreased hepatic infiltration of proinflammatory myeloid populations, particularly mature dendritic cells (DCs) in Gsk3β△End mice. In a co-culture system, GSK3β in lipotoxic LSECs promoted DCs maturation. Mechanistically, GSK3 inhibition restored lipotoxicity-induced alterations in LSEC mitochondrial morphology and respiration by regulating AMP-activated protein kinase and dynamin-related protein 1. This rescue suppressed chemokines and adhesion molecules expression, thereby limiting immune cell recruitment. Collectively, under lipotoxic stress, GSK3β amplifies mitochondrial dysfunction and inflammatory signaling in LSECs, enhancing myeloid cell homing and DC maturation. Targeting LSEC GSK3β may therefore represent a promising therapeutic strategy to mitigate LSEC driven fibro inflammatory response in human MASH.

Human γδ T cells are a rare but functionally diverse lymphocyte subset critical for tumor surveillance and antimicrobial immunity. Although they express natural killer (NK) cell-associated receptors such as Killer-cell Immunoglobulin-like Receptors (KIRs), the relevance of KIR expression on γδ T cells remains largely unexplored. Using flow cytometry, ATAC-seq and RNA-seq, we identified KIR expression as a marker that distinguished two functionally and molecularly distinct γδ T cell subsets. KIR⁺ γδ T cells exhibited an advanced, memory-like differentiation state characterized by heightened cytotoxicity, stable epigenetic remodeling and a predominant IFNγ-producing profile. In contrast, KIR⁻ γδ T cells maintained a naïve-like phenotype and preferentially produced IL-17 upon polarization. Notably, KIR+ γδ T cells were consistently observed across individuals but were significantly enriched in cytomegalovirus (CMV)-seropositive donors, suggesting that chronic antigenic stimulation could promote the emergence of KIR⁺ effector γδ T cells. These findings reveal a functional dichotomy in human γδ T cells defined by KIR expression, linking IFNγ-driven cytotoxicity with KIR⁺ cells and IL-17 production with KIR⁻ cells. This insight advances our understanding of γδ T cell heterogeneity and has implications for viral immunity, immune memory and the development of γδ T cell-based immunotherapies.

Survival after lung transplantation is limited by chronic, progressive graft failure, termed chronic lung allograft dysfunction (CLAD). Graft-resident mesenchymal cells (MCs) drive CLAD pathogenesis and exhibit stable dysregulated signaling, yet the transcriptomic and epigenomic drivers underlying this fibrogenic transformation remain elusive. We used single-cell multi-omic profiling to characterize gene expression and chromatin accessibility in MCs isolated from lavage fluid of lung transplant recipients with and without CLAD, collected early post-transplantation or after disease onset. MCs obtained after CLAD onset demonstrated a distinct transcriptomic signature compared with non-CLAD controls, enabling classification of disease status at the single-cell level with > 98% accuracy using signature genes. Chromatin accessibility analyses identified enrichment of CCAAT-enhancer-binding protein family transcription factors, specifically CEBPD, in CLAD MCs. Early post-transplant MCs showed minimal accessibility differences, suggesting that CEBPD-associated regulatory changes emerge over time. Integration analyses identified eight MC states and a CLAD-specific shift towards a fibrotic state. CEBPD, SOX4, and FOXP2 were identified as putative regulators of this state with substantial overlap in predicted targets. Targeting CEBPD reversed fibrotic phenotypes of CLAD MCs (decreased ECM expression, contractility, proliferation, and migration). Together, these data provide insights into transcriptomic and epigenomic changes in post-transplant MCs, nominating biomarkers and therapeutic targets.