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Abstract
Heterogeneity in disease severity and treatment response in inflammatory bowel disease (IBD) likely evolve from individual differences in host-microbiota-immune interactions. Histological evaluation of intestinal biopsies is central to diagnosis, but histological parameters that define underlying immune mechanisms are limited. We investigated histological features that distinguish individual patient immune profiles in therapy-naive paediatric IBD patients (age 6‒18-years-old) using biopsy immunohistochemistry and transcriptomics and plasma proteomics across two cohorts. High colonic epithelial expression of Secretory Leukocyte Protease Inhibitor (SLPI), a microbiota-induced regulator of epithelial function, occurred in IBD patients with high clinical disease activity and more severe endoscopic and microscopic disease activity. SLPI expression related to increased neutrophil infiltration, transcriptomic signatures of activation and genes known to associate with therapeutic resistance. High SLPI co-localized with high densities of IL-17-secreting cells and was associated with high plasma concentrations of Th17-related immune proteins. Additionally, patients with high intestinal SLPI had an intrinsically different immunotype, in which circulating neutrophils exhibited altered transcription of genes involved in neutrophil granule formation, phagocytosis, oxidative phosphorylation, and interferon signalling. Thus, high colonic SLPI expression at diagnosis associates with severe IBD, increased IL-17A-neutrophil pathway responses and altered transcriptomic wiring of circulating neutrophils.
Authors
Sandrine Nugteren, Beatriz Calado, Ytje Simons-Oosterhuis, Daniëlle H. Hulleman-van Haaften, Willem K. Smits, Renz C.W. Klomberg, Bastiaan Tuk, Mohammed Charrout, Dicky J. Lindenbergh-Kortleve, Michail Doukas, Mathijs A. Sanders, Gregory van Beek, Johanna C. Escher, Lissy de Ridder, Maria Fernanda Pascutti, Janneke N. Samsom
Abstract
Viral lower respiratory tract infections are common early in life and are associated with long-term development of asthma, a chronic condition defined by reversible airflow obstruction secondary to inflammation. Understanding the immunologic mechanism connecting these two pathologies observed early in life becomes imperative to guide therapeutic measures. To investigate this connection, neonatal (day of life 4-6) or adult mice were infected with human metapneumovirus (HMPV) followed by a secondary HMPV infection 6 weeks later. Mice initially infected as neonates demonstrate increased mucus production, eosinophil recruitment, airway hyperresponsiveness, and Th2 T-cell differentiation following re-challenge compared to adult mice rechallenged with HMPV. Neonatal HMPV infection led to formation of Th2 clonally expanded tissue resident memory (TRM) T cells that were absent after adult HMPV. FTY720-mediated disruption of lymphocyte circulation demonstrated TRMs contribute to pathology. Local depletion of lung CD4+ T cells and JAK2-inhibition mitigated pathology. These findings suggest TRMs uniquely generated after early life viral infection can contribute to Th2-driven asthma pathology.
Authors
Emma E. Brown, Jie Lan, Olivia B. Parks, Li Fan, Dequan Lou, Alysia McCray, Lisa Mathews, Alexander J. Wardropper, Anna Shull, Michelle L. Manni, Hēth R. Turnquist, Kong Chen, Taylor Eddens
Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global health concern with limited interventions. While the role of gut bacteria in MASLD has been extensively studied, the contribution of gut fungi remains largely unexplored. This study investigates the impact of fungal dysbiosis and the role of CARD9, a key adaptor protein in fungal sensing on gut-liver axis dysfunction in MASLD. Patients with advanced liver fibrosis exhibited distinct mycobiota profiles. Using a CARD9-deficient mouse model subjected to high-fat high-glucose/fructose feeding, we observed exacerbated liver injury and fibrosis accompanied by fungal dysbiosis, paralleling our findings in human patients. Beyond its established expression in myeloid cells, CARD9 was also detected in intestinal enterocytes where its expression was diminished under metabolic stress. Intestinal organoids with CARD9 inhibition had reduced expression of antimicrobial Reg3g, the tight junction protein ZO-1, and the antifungal enteroendocrine hormone PYY. These findings suggest that CARD9 maintains gut barrier integrity, preventing microbial translocation and subsequent liver injury and fibrosis. Our results provide new insights into the interplay between fungal dysbiosis, gut barrier dysfunction, and MASLD, and identify CARD9 as a key protein within this axis.
Authors
Vijay Pandyarajan, So Yeon Kim, Takashi Tsuchiya, Selena Liu, Sadam H. Bhat, Jieun Kim, David M. Underhill, Mazen Noureddin, Shelly C. Lu, Ekihiro Seki
Abstract
BACKGROUND. High-dose influenza vaccine, containing four times more antigen than standard-dose, is recommended for people aged ≥ 65 years, but there is a knowledge gap surrounding its effect in people with HIV (PWH), who remain more vulnerable to serious influenza infections than people without HIV (PWoH) despite virological suppression. The primary goal of this study was to assess whether high-dose improves antibody responses in PWH, with a particular focus on older PWH. METHODS. We conducted a study to assess antibody responses to sequential high- versus standard-dose influenza vaccination in PWH. Young (18-40 years) PWoH (n=55) and PWH (n=37); and older (≥ 60 years) PWoH (n=72) and PWH (n=67) received standard-dose during the 2020-2024 seasons and 123 participants, including 41 older PWH, received high-dose the consecutive season. All PWH were virologically suppressed on ART. Hemagglutination inhibition (HAI) titer and HA-specific IgG were analyzed at 0- to 180-days post-vaccination (dpv); T cell activation-induced responses were assessed by flow cytometry. RESULTS. All groups mounted significant HAI and IgG responses to all vaccine antigens at 28 dpv, after standard- and high-dose vaccination. Responses to A/H1N1 were lower in magnitude and durability in older PWH compared to young PWoH following standard-dose and were not boosted with high-dose, whereas high-dose enhanced A/H3N2 and B/Victoria IgG, and CD4+ T cell responses to all antigens, in older PWH. CONCLUSION. Our data demonstrate partial efficacy of high-dose in augmenting antibody responses of older PWH while highlighting limitations in boosting A/H1N1-specific responses. TRIAL REGISTRATION. ClinicalTrials.gov NCT04487041. FUNDING. NIH grant (5R01AG068110).
Authors
Jonah Kupritz, Sheldon Davis, TianHao Liu, Prabhsimran Singh, Daniel Andrés Díaz–Pachón, Allan Rodriguez, Scott D. Boyd, Rajendra Pahwa, Suresh Pallikkuth, Savita G. Pahwa
Abstract
Aberrant neutrophil (PMN) accumulation in the tissue induces chronic vascular diseases. Endothelial cells (ECs) regulate the access of PMNs into the tissue from the blood. However, the mechanisms that prevent PMNs from being activated and accumulating in the tissue, a hallmark of acute lung injury (ALI), remain elusive. We demonstrate that conditional deletion of Erg in ECs spontaneously alters the PMN transcriptome, which is enriched with genes that induce PMN recruitment, adhesion, activation, and 'do not eat me' signals due to impaired synthesis of the deubiquitinase, A20. Decreased A20 levels, in turn, activated the transcription factor NFκB and the secretion of MIP2α (human homolog of IL8) in ECs. EC-secreted MIP2α/IL8 engaged the CXCR2 cascade on PMNs, leading to their activation and inflammatory injury. These findings were recapitulated in the lungs and blood of PMNs from patients dying of ALI. Overexpression of the A20 gene in EC or pharmacological inhibition of CXCR2 on PMNs in iEC-Erg–/– mice rescued EC control of PMNs and tissue homeostasis, and enhanced mouse survival after pneumonia. Thus, the EC-Erg-A20 axis regulates PMN accumulation and hyperactivation in the lungs by inhibiting EC-mediated IL-8 activation of PMN-CXCR2, thereby providing a potential target for neutrophilic inflammatory vascular diseases.
Authors
Vigneshwaran Vellingiri, Vijay Avin Balaji Ragunathrao, Jagdish Chandra Joshi, Md Zahid Akhter, Mumtaz Anwar, Somenath Banerjee, Sayanti Datta, Viktor Pinneker, Steven M. Dudek, Yoshikazu Tsukasaki, Sandra Pinho, Dolly Mehta
Abstract
Immune checkpoint inhibitors (ICIs) can cause immune-related adverse events (irAEs), with acute interstitial nephritis (ICI-AIN) being the most common irAE. While the exact mechanism remains unclear, upregulation of interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) pathways has been implicated. This study used a humanized chimeric PD-1/PD-L1 mouse model to assess renal effects of ICIs, alone or combined with pro-inflammatory cytokines, and to test if selective TNF-α blockade could prevent ICI-AIN. Mice were randomly divided into four experimental groups: Control, ICI-Only, ICI-Cytokines (ICI-Cyt), and ICI-Block (ICI-TNF-α blockade). Renal function and cytokine profiles were assessed, while kidney tissue was analyzed using microscopy and single-cell RNA sequencing. Histology revealed increased renal infiltration of CD4⁺/CD8⁺ T cells in ICI-treated groups and decreased TNF-α expression following TNF-α blockade. Additionally, kidney tissue ELISA demonstrated reduced IFN-γ levels following TNF-α blockade. Plasma IL-6, MCP-1, and TNF-α were lower in ICI-Block mice. Single-cell RNA sequencing revealed shifts in immune cell populations and genes of interest including: Bcl2a1, Icos, Il18r1, Ccr2, and Jaml. This humanized model replicates ICI-AIN key features, revealing a synergistic role of ICIs and pro-inflammatory cytokines. TNF-α blockade demonstrated protective effects, supporting its potential role in mitigating the risk of ICI-AIN.
Authors
Victor D. Cuenca Narvaez, Coraima Nava Chavez, Omar Al Refai, Johanna E. J. Jacobs, Luis E. Gutierrez, Song Zhang, Xiaoyan Li, Jacob B. Hirdler, Michael F. Romero, Joerg Herrmann, Xiaogang Li, Haidong Dong, Alfonso Eirin, Sandra M. Herrmann
Abstract
This study provides a comprehensive evaluation of the cutaneous adipose tissue (CAT) transcriptome in psoriasis patients and investigates the effects of IL-17 blockade on CAT inflammation through a randomized placebo-controlled trial using secukinumab (ObePso-S study, NCT03055494). RNA sequencing analysis of CAT biopsies from 82 psoriasis patients revealed 2132 differentially expressed transcripts compared to healthy controls. Notably, significant gene dysregulation was observed in both lesional skin (LS)- and non-lesional (NL)-CAT, including activation of IL-17-driven pathways, antimicrobial peptide-related, and neutrophil degranulation signatures. Stratification by obesity demonstrated that obese psoriatic CAT exhibited more than 2-fold higher number of differentially expressed genes than non-obese counterparts, suggesting a synergistic interaction between psoriasis and obesity in driving CAT inflammation. Treatment with secukinumab markedly improved inflammatory signatures in psoriatic CAT, with greater improvements observed in obese patients. These findings reveal a pronounced and partially dependent on IL-17-dependent inflammatory phenotype in psoriatic CAT, challenge the conventional concept of psoriasis as a solely superficial skin disease, and highlight CAT as an important contributor to systemic inflammation in psoriasis.
Authors
Naomi Shishido-Takahashi, Sandra Garcet, Inna Cueto, Hong Beom Hur, Elisa F. Muscianisi, Jennifer Steadman, Andrew Blauvelt, James G. Krueger
Abstract
GLP-1 receptor (GLP-1R) agonists decrease blood glucose and body weight and reduce rates of cardiovascular and renal disease. Although GLP-1R activation lowers blood pressure (BP), the underlying mechanisms remain incompletely understood and have been attributed to weight loss and endothelial cell GLP-1R signaling. Here, we show that GLP-1Rs in vascular smooth muscle cells (VSMCs) are essential for semaglutide-mediated BP reduction in mice. In contrast, GLP-1Rs in Tie2+ endothelial or immune cells are not required for semaglutide to lower BP. The VSMC GLP-1R is dispensable for the effects of semaglutide on food intake, body weight, and blood glucose, but is required for its actions to increase glomerular filtration rate and promote natriuresis. Systemic semaglutide administration resulted in proteomic changes in the renal artery and kidney in pathways related to platelet aggregation, fibrin clot formation, lipid metabolism, and pro-apoptotic signaling that are abolished in mice lacking VSMC GLP-1R expression. Moreover, semaglutide directly induced vasorelaxation in pre-constricted mesenteric arteries ex vivo. Together, these findings identify VSMCs as a key cellular target linking GLP-1R activation to BP regulation, renal electrolyte excretion, and proteomic changes in renal artery and kidney.
Authors
Kyle D. Medak, Jacqueline A. Koehler, Laurie L. Baggio, Maria J. Gonzalez-Rellan, Chi Kin Wong, Xiemin Cao, Vivikta Rao, Sean Kao, Yu Cui, Jiayi Fu, Easton Liaw, M. Golam Kabir, Jie Zhang, Jin Wei, Daniel J. Drucker
Abstract
Insulin and glucagon are described to have opposing actions on hepatic glycogen metabolism. However, here we showed that their coordinated action promoted glycogen turnover and meal glucose storage. In mice, pharmacological doses of insulin or glucagon failed to alter hepatic glycogen, but the combination produced a robust decrease in glycogen content. Additivity between insulin and glucagon was also seen with the activation of hepatic insulin signaling intermediates. This signaling pathway drove glycogen synthesis, suggesting concurrent actions on glycogen breakdown and repletion. A mixed nutrient meal, which stimulates an increase in both insulin and glucagon, enhanced the incorporation of dietary glucose into hepatic glycogen. This was much more pronounced than the effects of glucose alone, which only stimulated insulin secretion. These findings revealed that glucagon is required for efficient hepatic glucose storage when acting in concert with insulin. Coordinated insulin-glucagon signaling thus emerged as a critical mechanism for hepatic glycogen cycling, challenging the classical paradigm that these hormones work in opposition.
Authors
Nidhi Kejriwal, David Bouslov, Cheyenne R. Castle, Riya S. Karve, Galina A. Arkharova, Ashot Sargsyan, Daniel J. Drucker, Guo-Fang Zhang, David A. D'Alessio, Jonathan E. Campbell, Megan E. Capozzi
Abstract
Patients with COVID-19 who develop platelet-activating antibodies represent a subset at heightened thrombotic risk, yet the immune features associated with this response remains to be defined. We applied single-cell RNA sequencing of B- and T-cells, single B-cell V(D)J sequencing, and plasma cytokine and chemokine analysis to define immune signatures distinguishing patients who did (PEA+) or did not (PEA–) develop these antibodies. PEA⁺ patients showed prominent transcriptional enrichment of inflammatory, antigen-presentation, and B-cell receptor signaling pathways within antigen-experienced B-cell subsets. Expanded B-cell clones in PEA+ patients were disproportionately enriched within atypical memory B-cells and exhibited upregulated IFN-γ–response signatures, increased proliferative mutational patterns, limited class switching, and a significant overrepresentation of RKH/Y5 heavy-chain motifs associated with platelet-activating antibodies, consistent with an extrafollicular-biased response. Parallel T-cell profiling revealed IL-12 pathway enrichment across most T-cell subsets, increased IFN-γ transcription, and elevated plasma levels of Th1-associated cytokines in PEA+ patients. Collectively, these data highlight a coordinated inflammatory environment marked by Th1-skewed T-cell activation and selective expansion of atypical memory B-cell clones carrying RKH/Y5 motifs, defining immunologic features associated with platelet-activating antibody development in COVID-19.
Authors
Nathan Witman, Mei Yu, Yuqi Zhang, Kexin Gai, Yuhong Chen, Lu Zhou, Christine Nguyen, Wen Zhu, Yongwei Zheng, Shawn M. Jobe, Mary Beth Graham, Weiguo Cui, Demin Wang, Renren Wen
Abstract
Authors
Caitlin M. Pavelec, Leigh A. Bradley, Priyanka Rawat, Luke S. Dunaway, Maya Bolger-Chen, Bethany A. Gholson, Jonathan R. Lindner, Brant E. Isakson, Norbert Leitinger, Matthew J. Wolf
Abstract
While the pathogenic role of autoantibodies targeting the podocyte protein THSD7A in membranous nephropathy (MN) is well described, the consequences of autoantibody binding for podocyte homeostasis and the function of THSD7A remain unclear. Here, we induced an MN model in control and podocyte-specific Thsd7a knockout (Thsd7a–/–) mice using rabbit anti-THSD7A antibodies, followed by transcriptome and proteome analyses. Anti-THSD7A antibodies in WT mice caused significant loss of key slit diaphragm (SD) proteins such as nephrin and NEPH1, without transcriptional downregulation. Glomeruli showed substantial transcriptomic and proteomic reconfiguration indicative of extensive podocyte injury, including disruptions in podocyte adhesion, cytoskeletal dynamics, and marked upregulation of ubiquitin-proteasome system components, cathepsins and ADAM proteases. Notably, experiments in C3-deficient mice revealed that proteolytic activation and SD protein loss are driven by complement-independent pathways. While Thsd7a–/– mice only displayed a mild phenotype under basal conditions, they were completely protected from MN development upon anti-THSD7A antibody transfer. Finally, interactomic analysis identified a protein complex including THSD7A and integrin α3, linking THSD7A complexes to pathogenic regulation of cytoskeleton, adhesion, and membrane signaling in MN. Thus, anti-THSD7A antibodies induce profound molecular reconfiguration, including dysregulated proteolytic systems via a complement-independent pathway, revealing potential therapeutic targets in MN.
Authors
Ming Huang, Moritz Lassé, Silke Dehde, Felicitas E. Hengel, Fatih Demir, Anja M. Billing, Ning Song, Larissa Seifert, Oliver Kretz, Florian Grahammer, Ulf Panzer, Sebastian Brähler, Tobias B. Huber, Gunther Zahner, Markus M. Rinschen, Nicola M. Tomas
Abstract
Fanconi anemia (FA) is the most common bone marrow failure (BMF) syndrome. Beyond a role in DNA repair, FA genes have a role in suppressing DNA-RNA hybrids, termed R-loops, which can be generated via RNA polymerase (RNAP)-mediated transcription. However, how these processes, including a role in fate determination of hematopoietic stem cells (HSCs), are related to BMF is largely unknown. Additionally, single FA gene knockouts in mice do not recapitulate most phenotypes observed in FA patients. Thus, we generated a mouse model for FA by introducing heterozygous Setd2, which restricts RNAP-dependent transcription. Here, we show that FA patient-derived cells and Setd2+/– Fanca–/– HSCs share increased R-loop as well as dsRNA levels, and a ribosomal biogenesis defect. Further, Setd2+/– Fanca–/– HSCs display cell cycle arrest, mitotic errors and BMF phenotypes. Importantly, utilizing our Setd2+/– Fanca–/– mice, we discovered that Juglone, a pan RNAP inhibitor, reduces R-loop and dsRNA and reverses ribosomal biogenesis defects and mitotic errors, thereby rescuing BMF. In conclusion, this study establishes a novel mouse model that underscores a key role for R-loop formation, ribosomal biogenesis defects and mitotic errors in HSCs in driving BMF in Fanconi anemia. We also introduce a potential therapeutic avenue based upon pan-inhibition of RNA polymerases utilizing Juglone.
Authors
Michihiro Hashimoto, Xiaomin Feng, Jie Bai, Huimin Zeng, Tian Li, Jue Li, Terumasa Umemoto, Paul R. Andreassen, Gang Huang
Abstract
Improper light focus on the retina, refractive error, is primarily caused by eye size differences and is the leading cause of vision loss worldwide. C-terminal variants in the Myelin Regulatory Factor (MYRF) gene, a retinal pigment epithelium (RPE)-derived transcription factor, lead to isolated nanophthalmos characterized by a small, though structurally sound eye. However, other MYRF loss-of-function variants cause syndromic disease. To address this discrepancy, in vitro and animal studies were performed on a pathogenic C-terminal variant dG-MYRF (p.Gly1126fs30*, c.3376-1G>A). Human RPE-cells or primary RPE transduced with dG-MYRF showed reduced target gene expression, with decreased steady-state levels of the C-terminal cleavage product, but normal cleavage and localization. A homozygous humanized MYRF C-terminal mouse model (MyrfhumdG/humdG) was embryonic lethal by embryonic day (E) 18.5, while wildtype (MyrfhumWT/humWT) mice were viable. Single-cell RNA-seq from E17.5 MyrfhumdG/humdG and knockout RxCre;Myrffl/fl (E15.5 and P0) mice revealed shared differentially expressed genes, with decreased effect size in the MyrfhumdG/humdG eyes. These findings support dG-MYRF as a hypomorphic allele. Additionally, two MYRF splicing variants creating nonfunctional isoforms were found in families with isolated nanophthalmos. Overall, hypomorphic MYRF alleles underlie isolated nanophthalmos, supporting a tissue-specific threshold effect and highlighting unique roles for the MYRF C-terminus in the RPE.
Authors
Gabrielle M. Rozumek, Michelle L. Brinkmeier, Bin Guan, Su Qing Wang, Catherine Tower, Nina T. Yang, Rachel S. Lim, Dejuan Kong, Daniel Soden, Qitao Zhang, John Y.S. Han, Jason M.L. Miller, Lijin Dong, D. Ford Hannum, Sayoko E. Moroi, Julia E. Richards, Robert B. Hufnagel, Lev Prasov
Abstract
Mitochondrial dysfunction devastates the heart in major cardiovascular diseases, yet the mechanisms governing mitochondrial quality control remain elusive. We discovered that TIGAR (TP53-induced glycolysis and apoptosis regulator) deficiency established profound cardiac protection through developmental epigenetic programming of Parkin expression. Using whole-body and cardiomyocyte-specific TIGAR knockout mice, we demonstrated remarkable cardioprotection following myocardial infarction with maintained ejection fraction, and complete resistance to diet-induced cardiac hypertrophy despite comparable weight gain. TIGAR deficiency triggered dramatic increases in Parkin expression across all somatic tissues except testes, where Parkin levels remained extraordinarily high (100-fold greater than cardiac levels) regardless of TIGAR status, revealing tissue-specific regulatory mechanisms. This protection was entirely Parkin-dependent, as double knockout mice lost all cardioprotective benefits. Crucially, adult TIGAR manipulation failed to alter Parkin levels, demonstrating that this pathway operated exclusively during critical developmental windows to program lifelong cardiac resilience. Whole-genome bisulfite sequencing identified reduced DNA methylation in Prkn intron 10 as the key regulatory mechanism, with CRISPR deletion dramatically increased Parkin expression in multiple cell lines. Our findings reveiled how early cardiac metabolism programmed lifelong cardiac function through epigenetic mechanisms, and identifyied developmental metabolic programming as a potential therapeutic target for preventing both ischemic heart disease and metabolic cardiomyopathy.
Authors
Yan Tang, Stanislovas S. Jankauskas, Li Liu, Xujun Wang, Alus M. Xiaoli, Fajun Yang, Gaetano Santulli, Daorong Feng, Jeffrey E. Pessin
Abstract
The cardiac conduction system (CCS) develops asymmetrically along the body axes. In heterotaxy syndrome—resulting from aberrant left–right (L–R) axis formation—atrial and atrioventricular conduction defects can cause life-threatening arrhythmias. However, the developmental mechanisms regulating the atrioventricular conduction system (AVCS) disposition and integrity remain unclear. To investigate the etiology of AVCS malformations in laterality defects, we analyzed CCS development and function in mouse mutants for Cryptic and Lefty1, which are key regulators of Pitx2 in the L–R axis formation. Cryptic–/– embryos exhibited bilateral sinoatrial (SA) nodes and an ectopic anterior AV node and bundle accompanied by reduced Pitx2 expression. In contrast, Lefty1–/– embryos showed a hypoplastic SA node and AV node–bundle dissociation with ectopic Pitx2 expression. Single-cell transcriptomic analysis of Pitx2–/– hearts revealed expansion of AV node and bundle populations, consistent with a repressive role of Pitx2 in AVCS specification. Genetic lineage tracing indicated that Pitx2-expressing cells from the left lateral plate mesoderm populate cranioventral cardiac regions, where AVCS development is suppressed. Together, these findings clarify how global L–R axis information is locally integrated to shape AVCS disposition and integrity, providing a mechanistic model for AVCS abnormalities in laterality-associated congenital heart disease.
Authors
Kunihiko Joo, Ryohei Matsuoka, Keiko Kitajima, Kenta Yashiro, Akira Shiose, Ryuji Tominaga, Michael M. Shen, Shinya Oki, Chikara Meno
Abstract
Synthetic prostaglandin analogues, such as latanoprost, are first-line treatments to reduce intraocular pressure (IOP) in the management of glaucoma, treating millions of patients daily. Glaucoma is a leading cause of blindness, characterized by progressive optic neuropathy, with elevated IOP being the sole modifiable risk factor. Despite this importance, the underlying latanoprost mechanism of action is still not well defined, being associated with both acute and long term activities, and a growing list of ocular side effects. Prostaglandins are eicosanoid lipid mediators. Yet, there has not been a comprehensive assessment of small lipid mediators in glaucomatous eyes. Here we performed a lipidomic screen of aqueous humour sampled from glaucoma patients and healthy control eyes. The resulting signature was surprisingly focused on significantly elevated levels of arachidonic acid (AA) and its derivative, the ant-inflammatory and cytoprotective mediator, lipoxin A4 (LXA4) in glaucoma eyes. Subsequent experiments reveal that this response is drug-induced, due to latanoprost actions on trabecular meshwork cells, rather than a consequence of elevated IOP. We demonstrate that increased LXA4 inhibits pro-inflammatory cues and promotes TGF-β production in the anterior chamber. In concert, an autocrine prostaglandin circuit mediates canonical rapid IOP-lowering. This work reveals parallel mechanisms underlying acute and long-term latanoprost activities during glaucoma treatment.
Authors
David J. Mathew, Shubham Maurya, Julian Ho, Izhar Livne-Bar, Darren Chan, Jenny Wanyu Zhang, Yvonne M. Buys, Marisa Sit, Graham Trope, Donna M. Peters, John G. Flanagan, Karsten Gronert, Jeremy M. Sivak
Abstract
Fontan-associated liver disease (FALD) is a frequent complication in single ventricle patients palliated with the Fontan operation. FALD severity can impact clinical decisions; however, the pathophysiology of FALD progression is unknown. Single-cell spatial transcriptomics (ST) was performed on liver explant tissue sections from FALD patients with early (n=1) and advanced fibrosis (n=1) using CosMxTM Spatial Molecular Imaging with in-situ hybridization of 6000 genes. Immunofluorescence for liver zonation and cellular stress markers was performed to confirm protein expression based on ST analysis in additional FALD tissues (n=18). Unbiased clustering yielded 12 liver cell types, comprising six subtypes of hepatocytes. FALD with advanced fibrosis demonstrated expansion of mid-zonal hepatocytes, accompanied by loss of zonal markers characteristic of canonical pericentral and periportal hepatocytes. A subset of hepatocytes in advanced FALD demonstrated increased cellular stress and a redundant zonal phenotype, which we have termed zonally ambiguous and stressed hepatocytes. CellChat analysis revealed that ectopic WNT2 signaling is likely driving disrupted hepatocyte zonation. To corroborate these bioinformatic findings, we performed immunofluorescence staining of FALD specimens, which confirmed a disruption of liver zonation, and a significant increase in heat shock protein 70 (HSP70). Lastly, HSP70 expression strongly correlated with the Congestive Hepatic Fibrosis (CHF) score. Thus, single-cell ST has identified a unique population of hepatocytes with features of cellular stress and redundant zonal gene expression specific to advanced FALD. Further studies on hepatocyte metabolic function in Fontan patients will lead to a greater understanding of FALD development and progression during chronic maladaptation.
Authors
Brandon M. Lehrich, Jordann N. Lewis, Vik Meadows, Lori Schmitt, Mylarappa B. Ningappa, Jia-Jun Liu, Silvia Liu, Catherine K. Gestrich, Victor O. Morell, Rakesh Sindhi, Satdarshan P. Monga, Anita Saraf
Abstract
Authors
Johanna Tennigkeit, Maurice Wiegelmann, Chiara Massa, Jonas Lübcke, Werner Dammermann, Karina Börner, Filip Schröter, Barbara Seliger, Maximilian Kleinert, Oliver Ritter, Gregor Sachse
Abstract
Heart failure (HF) persists as the primary cause of death among patients recovering from acute myocardial infarction (AMI). Protein ubiquitination has been implicated as a key modulator of HF pathogenesis, yet the role of ubiquitination in the Aldh2 rs671 mutant—the most common single-nucleotide variant in human populations—remains poorly understood. We discovered TRIM21 as a previously unrecognized E3 ubiquitin ligase for the ALDH2 rs671 mutant and elucidated its mechanistic involvement in HF progression. Using Aldh2 bone marrow chimeric mice to model AMI, we observed that wild-type mice transplanted with Aldh2 rs671 donor bone marrow developed severe myocardial fibrosis and markedly reduced cardiac systolic function two weeks post-infarction compared to controls. This phenotype arose from defective macrophage efferocytosis caused by myeloid-specific Aldh2 rs671 mutation. Through high-resolution mass spectrometry proteomics, we identified TRIM21 as the E3 ligase targeting ALDH2. TRIM21 catalyzed K48-linked ubiquitination at ALDH2 lysine 73. Macrophage-specific Trim21 knockdown via AAV-shTrim21 reversed both the exacerbated cardiac fibrosis and systolic dysfunction by restoring macrophage efferocytosis. These findings delineate the upstream E3 ubiquitin ligase and the ubiquitination site of ALDH2, revealing a potential therapeutic target for HF.
Authors
Tianrui Han, Xin Wen, Yunyun Guo, Xiangkai Zhao, Jian Zhang, Yuguo Chen, Feng Xu
