Faculty Bibliography

Lymphatic vessels activate anti-tumor immune surveillance and support metastasis. Whether there are distinct lymphatic phenotypes that govern immunity and metastasis remains unclear. Here we reveal that cytotoxic immunity normalizes lymphatic function and uncouples immune and metastatic potential. We demonstrate that intratumoral lymphatic vessel density negatively correlates with cytotoxic immunity and that IFNγ reprograms the intratumoral lymphatic state. Lymphatic deletion of Ifngr1 expanded the intratumoral lymphatic network and drove the emergence of a tip-like state that promotes lymph node metastasis but not dendritic cell migration or response to immune checkpoint blockade (ICB). Mechanistically, IFNγ restrains proliferation and cell state programs through inhibition of mitochondrial respiration. Lymphatic-specific inhibition of mitochondrial complex III restrained the intratumoral tip-like state, blocked metastasis, and enhanced the response to ICB. Our data reveal that IFNγ induces a metabolic and phenotypic switch in tumor-associated lymphatic vessels that blocks regional metastasis and reinforces immune surveillance.

Chronic wounds, especially in diabetic patients, pose a significant clinical challenge due to impaired microvasculature and delayed healing. This study presents Exo-Q, a novel thermoresponsive hydrogel formed by co-gelation of engineered Q protein nanofibers with exosomes, a class of vesicular intercellular communication mediators. Exo-Q transitions from a gel to a viscoelastic solution at physiological temperature, enabling localized, topical delivery of exosomes with an initial burst release followed by sustained release. In a diabetic mouse wound model, Exo-Q effectively delivered human bone marrow multipotent stromal cell-derived exosomes directly to the wound bed, where they accumulated in endothelial cells of granulation tissue without detectable systemic distribution. Exosomes produced under stringent and replicable cell culture conditions consistently carried biomacromolecular cargo enriched for miRNAs with validated targets in angiogenesis-associated genes, indicative of their therapeutic potential. Topical application of Exo-Q resulted in extensive neovascularized granulation tissue, significantly accelerating wound closure to levels comparable to non-diabetic wounds. Importantly, the hydrogel's modular design maintained the functional integrity of Q protein nanofibers and exosomes, demonstrating compatibility with full-thickness human wounds. This platform allows for tailored customization to address critical stages of diabetic wound healing while ensuring efficacy at low dosages, potentially enabling patient-administered treatment. By leveraging advanced biomaterials, Exo-Q advances the therapeutic efficacy of exosome-based interventions for diabetic wounds, offering a localized, non-invasive solution to chronic, non-healing wounds. This innovative hydrogel platform represents a modular therapeutic strategy with significant potential for clinical applications in regenerative medicine.

Chronic wounds, especially in diabetic patients, pose a significant clinical challenge due to impaired microvasculature and delayed healing. This study presents Exo-Q, a novel thermoresponsive hydrogel formed by co-gelation of engineered Q protein nanofibers with exosomes, a class of vesicular intercellular communication mediators. Exo-Q transitions from a gel to a viscoelastic solution at physiological temperature, enabling localized, topical delivery of exosomes with an initial burst release followed by sustained release. In a diabetic mouse wound model, Exo-Q effectively delivered human bone marrow multipotent stromal cell-derived exosomes directly to the wound bed, where they accumulated in endothelial cells of granulation tissue without detectable systemic distribution. Exosomes produced under stringent and replicable cell culture conditions consistently carried biomacromolecular cargo enriched for miRNAs with validated targets in angiogenesis-associated genes, indicative of their therapeutic potential. Topical application of Exo-Q resulted in extensive neovascularized granulation tissue, significantly accelerating wound closure to levels comparable to non-diabetic wounds. Importantly, the hydrogel's modular design maintained the functional integrity of Q protein nanofibers and exosomes, demonstrating compatibility with full-thickness human wounds. This platform allows for tailored customization to address critical stages of diabetic wound healing while ensuring efficacy at low dosages, potentially enabling patient-administered treatment. By leveraging advanced biomaterials, Exo-Q advances the therapeutic efficacy of exosome-based interventions for diabetic wounds, offering a localized, non-invasive solution to chronic, non-healing wounds. This innovative hydrogel platform represents a modular therapeutic strategy with significant potential for clinical applications in regenerative medicine.

BACKGROUNDPlatelets are increasingly recognized as active participants in immune signaling and systemic inflammation. Upon activation, platelets form monocyte platelet aggregates (MPA) representing the crossroads of thrombosis and inflammation. We hypothesized that platelet transcriptomics could capture this thromboinflammatory axis and identify individuals at elevated cardiovascular risk.METHODS: MPA levels, defined as CD14+CD61+ cells, were measured using flow cytometry at 2 time points, 4 weeks apart, in healthy individualsPlatelets were isolated and sequenced. Individuals were categorized as MPAhi or MPAlo based on consistently high or low MPA levels across time points.RESULTSAmong 149 participants (median age 52 years, 57% female, 50% non-White), MPAhi individuals exhibited increased expression of platelet activation markers P-selectin (P < 0.001), PAC-1 (P = 0.021), and CD40L (P < 0.001) and enriched immune signaling pathways. Informed by MPA levels and derived from the platelet transcriptome, we developed a 42-gene thromboinflammation platelet signature (TIPS), which correlated with MPA levels in multiple cohorts and was reproducible over time. TIPS was elevated in patients with COVID-19 (P = 0.0002) and myocardial infarction (Padj = 0.008), and as in predicted future cardiovascular events in patients who underwent lower extremity revascularization after a median follow-up of 18 months (adjusted for age, sex, race, and ethnicity [adjHR] 1.55, P = 0.006). Notably, TIPS was modifiable by ticagrelor (P = 0.002) but not aspirin.CONCLUSIONThese findings establish MPA as a biomarker of thromboinflammation and introduce TIPS, a platelet RNA signature, that captures thromboinflammation and provides a promising tool for cardiovascular risk stratification and a potential therapeutic target.TRIAL REGISTRATIONNCT04369664FUNDINGNIH R35HL144993, NIH R01HL139909, and AHA 16SFRN2873002 to JSB, DFG Walter-Benjamin-Programme 537070747 to AB.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with an increased risk of vascular dysfunction and cardiovascular disease. We validate our previously developed Systemic Lupus Erythematosus Activity Platelet-Gene Expression Signature (SLAP-GES) score and investigate its relationship with platelet activity and vascular health. SLAP-GES was associated with the SLE Disease Activity Index (Padj < 0.001) and consistent over time (r = 0.76; P = 9 × 10^-5). Moreover, SLAP-GES was associated increased platelet aggregation in response to submaximal epinephrine (P = 0.084), leukocyte platelet aggregates (P = 0.014), and neutrophil platelet aggregates (P = 0.043). SLAP-GES was also associated with impaired glycocalyx (P = 0.011) and brachial artery flow-mediated dilation (P = 0.045). Altogether, SLAP-GES is associated with SLE disease activity, platelet activity, and impaired vascular health.

Excessive accumulation of lipids within cardiomyocytes can sometimes initiate cardiomyopathy, while in other situations excess lipids do not cause harm. To understand how pathologic and non-pathologic lipid accumulation differ, we isolated lipid droplets (LDs) from two genetically altered mouse lines and from wild-type (WT) mice after an overnight fast. The LDs from MHC-peroxisomal proliferator-activated receptor γ1(MHC-Pparg1) transgenic mice were threefold larger than those from either fasted WT or non-cardiomyopathy MHC-diacylglycerol acyl transferase 1 (MHC-Dgat1) transgenic mice. Proteomic analysis of the LD-associated membrane proteins (LDAMPs) showed that MHC-Pparg1 LDs had less perilipin (PLIN). Proteins associated with lipolysis and LD formation (CIDEs and MTP), lipid synthesis, and Pparg signaling pathways were increased in MHC-Pparg1 LDAMPs. Unlike in MHC-Pparg1, MHC-Dgat1 LDAMPs exhibited increased mitochondrial peroxidative proteins with reduced adipose triglyceride lipase (Pnpla2), and Pparg coactivator 1 alpha (Pgc1A). Cardiomyocytes from MHC-Pparg1 hearts had transmission electron microscopy (TEM) images of ongoing lipolysis and greater amounts of lipolytic proteins. In contrast, images from MHC-Dgat1 cardiomyocytes showed more lipophagy. Consistent with the proteomic study and EM images, cardiac immunofluorescence staining showed that PLIN5 protein, thought to block LD lipolysis, was markedly reduced with MHC-Pparg1 overexpression, while hormone-sensitive lipase was increased. The autophagosome marker protein LC3B was increased in MHC-Dgat1 but not in MHC-Pparg1 hearts. Potentially toxic lipids like diacylglycerols and ceramides were increased in hearts but not LDs from MHC-Pparg1 mice. Our data indicate that cardiomyocyte LDs vary in size, composition, and metabolism. Cardiotoxicity was associated with greater LD lipolysis, which we postulate leads to intracellular release of toxic lipids.

PURPOSE/OBJECTIVE:The functional composition and diversity of the gut microbiome may affect breast cancer risk by modulation of systemic sex hormones. Gut bacteria with β-glucuronidase enzymatic activity may deconjugate estrogens, leading to increased estrogen reabsorption into the circulation thereby increasing breast cancer risk. We investigated the relationship between the gut bacterial microbiome and endogenous estrogens and related sex hormones in women with hormone receptor-positive breast cancer compared to healthy control women. The goal was to determine if the estrobolome (i.e., bacteria capable of modulating the body's circulated estrogen levels) was altered in those with breast cancer compared with controls. METHODS:In this prospective case-control study, postmenopausal women (n = 46) with newly diagnosed stage I-III estrogen and/or progesterone receptor-positive breast cancer were compared with healthy postmenopausal female controls (n = 22). Bacterial composition of the gut microbiome was analyzed by 16S rRNA gene sequencing from fecal specimens. Plasma and urine sex hormones were quantified using high-performance liquid chromatography/mass spectrometry. RESULTS:We found evidence that some β-glucuronidase positive bacteria were enriched in the breast cancer patients compared to healthy controls, whereas abundances of some β-glucuronidase negative bacteria were reduced. There was also a wide distribution of prevalence of β-glucuronidase positive taxa in both breast cancer subjects and healthy controls, as well as higher probability of breast cancer subjects having higher average β-glucuronidase levels. Significant differences were found in endogenous progesterone levels between the breast cancer patients and healthy controls. CONCLUSION/CONCLUSIONS:This pilot study showed differences in the gut microbiome and endogenous progesterone levels among postmenopausal women with hormone receptor-positive breast cancer compared with healthy controls. These interesting findings may have implications for breast cancer risk and prevention and warrant further exploration.

Lung adenocarcinomas (LUAD) are a pressing global health problem with enduring lethality and rapidly shifting epidemiology. Proteogenomic studies integrating proteomics and post-translational modifications with genomics can identify clinical strata and oncogenic mechanisms, but have been underpowered to examine effects of ethnicity, smoking and environmental exposures, or sex on this heterogeneous disease. This comprehensive proteogenomic analysis of LUAD tumors and matched normal adjacent tissues from 406 patients across diverse geographic and demographic backgrounds explores the impact of understudied driver mutations, prognostic role of chromosomal instability, patterns of immune signaling, differential and sex-specific effects of endogenous mutagens and environmental carcinogens, and pathobiology of early-stage tumors with "late-like" characteristics. Candidate protein biomarkers are proposed for unstable tumors with highly fragmented genomes and for carcinogen exposures, and a LUAD subtype-specific atlas of therapeutic vulnerabilities is presented. These observations and the associated data resource advance the objective of precision management strategies for this devastating disease.

Targeted therapies and immunotherapy have improved treatment outcomes for many melanoma patients. However, patients whose melanomas harbor driver mutations in the neurofibromin 1 (NF1) tumor suppressor gene often lack effective targeted treatment options when their tumors do not respond to immunotherapy. In this study, we utilized patient-derived short-term cultures (STCs) and multiomics approaches to identify molecular features that could inform the development of therapies for patients with NF1 mutant melanoma. Differential gene expression analysis revealed that the epidermal growth factor receptor (EGFR) is highly expressed and active in NF1 mutant melanoma cells, where it hyper-activates ERK and AKT, leading to increased tumor cell proliferation, survival, and growth. In contrast, genetic or pharmacological inhibition of EGFR hindered cell proliferation and survival and suppressed tumor growth in patient-derived NF1 mutant melanoma models but not in NF1 wild-type models. These results reveal a connection between NF1 loss and increased EGFR expression that is critical for the survival and growth of NF1 mutant melanoma cells in patient-derived culture and xenograft models, irrespective of their BRAF and NRAS mutation status.

AIM/OBJECTIVE:To investigate how psychosocial stress contributes to accelerated thrombosis, focusing on platelet activation and hyperreactivity. The specific objective was to identify novel platelet regulators involved in stress-mediated thrombosis, with a particular emphasis on the tetraspanin CD37. METHODS AND RESULTS/RESULTS:To explore how stress contributes to platelet hyperreactivity, platelets were isolated from (1) mice that experienced chronic variable stress and stress-free controls (n=8/group) and (2) human subjects with self-reported high and no stress levels (n=18/group), followed by RNA-sequencing. By comparing mutually expressed transcripts, a subset of genes differentially expressed following psychosocial stress was identified in both human and mouse platelets. In both mice and humans, platelet CD37 positively associates with platelet aggregation responses that underlie thrombosis, with Cd37-/- platelets exhibiting impaired integrin αIIbβ3 signaling, characterized by reduced platelet fibrinogen spreading and decreased agonist-induced αIIbβ3 activation. Consistent with a role for CD37 in regulating platelet activation responses, chimeric mice that received Cd37-/- bone marrow experienced a significantly increased time to vessel occlusion in the carotid artery FeCl3 model compared to mice reconstituted with wild-type bone marrow. CD37 deficiency did not alter hemostasis, as platelet count, coagulation metrics, prothrombin time, and partial thromboplastin time did not differ in Cd37-/- mice relative to wild-type mice. Consistent with this, bleeding time did not differ between wild-type and Cd37-/- mice following tail tip transection. CONCLUSIONS:This study provides new insights into the platelet-associated mechanisms underlying stress-mediated thrombosis. Identifying CD37 as a novel regulator of platelet activation responses offers potential therapeutic targets for reducing the thrombotic risk associated with psychosocial stress. The findings also contribute to understanding how psychosocial stress accelerates thrombotic events and underscore the importance of platelet activation in this process.