Combining 3D imaging and single-cell genomics, Jafree et al. uncover how kidney lymphatics are uniquely organized and how they are rewired in chronic transplant rejection. The cover image shows 3D reconstruction of a confocal image stack from immunolabeled and optically cleared human kidney tissue with chronic transplant rejection. Image credit: Daniyal Jafree and David Long.
Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive liver disease characterized by complex interactions between lipotoxicity, ER stress responses, and immune-mediated inflammation. We identified enrichment of the proinflammatory alarmin S100 calcium-binding protein A11 (S100A11) on extracellular vesicles stimulated by palmitate-induced lipotoxic ER stress with concomitant upregulation of hepatocellular S100A11 abundance in an IRE1A-XBP1s dependent manner. We next investigated the epigenetic mechanisms that regulate this stress response. Publicly available human liver ChIP-Seq GEO datasets demonstrated a region of histone H3 lysine 27 (H3K27) acetylation upstream to the S100A11 promoter. H3K27acetylation ChIP-qPCR demonstrated a positive correlation between lipotoxic ER stress and H3K27acetylation of the region, which we termed Lipotoxicity Influenced Enhancer (LIE) domain. CRISPR-mediated repression of the LIE domain reduced palmitate-induced H3K27acetylation and corresponding S100A11 upregulation in Huh7 cells and immortalized mouse hepatocytes. Silencing of the murine LIE in two independent steatohepatitis models demonstrated reduced S100a11 upregulation and attenuated liver injury. We confirmed H3K27acetylation and XBP1s occupancy at the LIE domain in human MASH liver samples and an increase in hepatocyte-derived S100A11-enriched extracellular vesicles in MASH patient plasma. Our studies demonstrate a LIE domain which mediates hepatic S100A11 upregulation. This pathway may be a potential therapeutic target in MASH.
P. Vineeth Daniel, Hanna L. Erickson, Daheui Choi, Feda H. Hamdan, Yasuhiko Nakao, Gyanendra Puri, Takahito Nishihara, Yeriel Yoon, Amy S. Mauer, Debanjali Dasgupta, Jill Thompson, Alexander Revzin, Harmeet Malhi
Bowen Yan, Qingchen Yuan, Marco M. Buttigieg, Prabhjot Kaur, Annalisse R. McKee, Daniil E. Shabashvili, Caitlyn Vlasschaert, Alexander G. Bick, Michael J. Rauh, Olga A. Guryanova
Plasminogen activator inhibitor-1 (PAI-1), encoded by SERPINE1, contributes to age-related cardiovascular diseases (CVD) and other aging-related pathologies. Humans with a heterozygous loss-of-function SERPINE1 variant exhibit protection against aging and cardiometabolic dysfunction. We engineered a mouse model mimicking the human mutation (Serpine1TA700/+) and compared cardiovascular responses with wild-type littermates. Serpine1TA700/+ mice lived 20% longer than littermate controls. Under L-NG-Nitro-arginine methyl ester (L-NAME)-induced vascular stress, Serpine1TA700/+ mice exhibited diminished pulse wave velocity (PWV), lower systolic hypertension (SBP), and preserved left ventricular diastolic function compared to controls. Conversely, PAI-1-overexpressing mice exhibited measurements indicating accelerated cardiovascular aging. Single cell transcriptomics of Serpine1TA700/+ aortas revealed a vascular-protective mechanism with downregulation of extracellular matrix regulators Ccn1 and Itgb1. Serpine1TA700/+ aortas were also enriched in a cluster of smooth muscle cells that exhibited plasticity. Finally, PAI-1 pharmacological inhibition normalized SBP and reversed L-NAME-induced PWV elevation. These findings demonstrate that PAI-1 reduction protects against cardiovascular aging-related phenotypes, while PAI-1 excess promotes vascular pathological changes. Taken together, PAI-1 inhibition represents a promising strategy to mitigate age-related CVD.
Alireza Khoddam, Anthony Kalousdian, Mesut Eren, Saul Soberanes, Andrew Decker, Elizabeth J. Lux, Benjamin W. Zywicki, Brian Dinh, Bedirhan Boztepe, Baljash S. Cheema, Carla M. Cuda, Hiam Abdala-Valencia, Arun Sivakumar, Toshio Miyata, Lisa D. Wilsbacher, Douglas E. Vaughan
Teplizumab, a humanized anti-CD3 monoclonal antibody, represents a breakthrough in autoimmune type 1 diabetes (T1D) treatment, by delaying clinical onset in stage 2 and slowing progression in early stage 3. However, therapeutic responses are heterogeneous. To better understand this variability, we applied single-cell transcriptomics to paired peripheral blood and pancreas samples from anti-mouse CD3-treated non-obese diabetic (NOD) mice and identified distinct gene signatures associated with therapy outcome, with consistent patterns across compartments. Success-associated signatures were enriched in NK/CD8⁺ T cells and other immune cell types, whereas resistance signatures were predominantly expressed by neutrophils. The immune communities underlying these response signatures were confirmed in human whole-blood sequencing data from the AbATE study at 6 months, which assessed teplizumab therapy in stage 3 T1D. Furthermore, baseline expression profiling in the human TN10 (stage 2) and AbATE (stage 3) cohorts identified immune signatures predictive of therapy response, T cell-enriched signatures in responders and neutrophil-enriched signatures in non-responders, highlighting the roles of both adaptive and innate immunity in determining teplizumab outcome. Using an elastic-net logistic regression model, we developed a 26-gene blood-based signature predicting teplizumab response (AUC = 0.97). These findings demonstrate the predictive potential of immune gene signatures and the value of transcriptomic profiling in guiding individualized treatment strategies with teplizumab in T1D.
Gabriele Sassi, Pierre Lemaitre, Laia Fernández Calvo, Francesca Lodi, Álvaro Cortés Calabuig, Samal Bissenova, Amber Wouters, Laure Degroote, Marijke Viaene, Niels Vandamme, Lauren Higdon, Peter S. Linsley, S. Alice Long, Chantal Mathieu, Conny Gysemans
Regulatory T-cells (Treg) are critical for maintaining immune homeostasis, and their adoptive transfer can treat murine inflammatory disorders. In patients, Treg therapies have been variably efficacious. Therefore, new strategies to enhance Treg therapeutic efficacy are needed. Treg predominantly depend upon oxidative phosphorylation (OXPHOS) for energy and suppressive function. Fatty acid oxidation (FAO) contributes to Treg OXPHOS and can be important for Treg “effector” differentiation, but FAO activity is inhibited by coordinated activity of isoenzymes acetyl-CoA Carboxylase-1 and -2 (ACC1/2). Here, we show that small molecule inhibition or Treg-specific genetic deletion of ACC1 significantly increases Treg suppressive function in vitro and in mice with established chronic GVHD. ACC1 inhibition skewed Treg towards an “effector” phenotype and enhanced FAO-mediated OXPHOS, mitochondrial function, and mitochondrial fusion. Inhibiting mitochondrial fusion diminished the effect of ACC1 inhibition. Reciprocally, promoting mitochondrial fusion, even in the absence of ACC1 modulation, resulted in a Treg functional and metabolic phenotype similar to ACC1 inhibition, indicating a key role for mitochondrial fusion in Treg suppressive potency. Ex vivo expanded, ACC1 inhibitor treated human Treg similarly augmented suppressor function as observed with murine Treg. Together, these data suggest that ACC1 manipulation may be exploited to modulate Treg function in patients.
Cameron McDonald-Hyman, Ethan G. Aguilar, Ewoud B. Compeer, Michael C. Zaiken, Stephanie Y. Rhee, Fathima A. Mohamed, Jemma H. Larson, Michael L. Loschi, Christopher Lees, Govindarajan Thangavelu, Margaret L. Sleeth, Kyle D. Smith, Jennifer S. Whangbo, Jerome Ritz, Tim D. Sparwasser, Roddy S. O'Connor, Peter A. Crawford, Jeffrey C. Rathmell, Leslie S. Kean, Robert Zeiser, Keli L. Hippen, Michael L. Dustin, Bruce R. Blazar
Pancreatic ductal adenocarcinoma (PDAC) has among the poorest prognosis and highest refractory rates of all tumor types. The reviews in this series, by Dr. Ben Z. Stanger, bring together experts across multiple disciplines to explore what makes PDAC and other pancreatic cancers so distinctively challenging and provide an update on recent multipronged approaches aimed at improving early diagnosis and treatment.
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