Essential role of protein kinase R in the pathogenesis of pulmonary veno-occlusive disease

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Abstract

Pulmonary veno-occlusive disease (PVOD) is a rare and severe subtype of pulmonary arterial hypertension, characterized by progressive remodeling of small pulmonary arteries and veins with no therapies. Using a mitomycin C (MMC)-induced rat model, we previously demonstrated that protein kinase R (PKR)-mediated integrated stress response (ISR) drives endothelial dysfunction and vascular remodeling. To determine if PKR is the primary mediator of ISR and the pathogenesis, we treated control (Ctrl) and PKR knockout (KO) mice with the same dose of MMC. Consistent with rat data, Ctrl mice displayed ISR activation, vascular remodeling, and pulmonary hypertension after MMC treatment, while KO mice showed none of these phenotypes. Proteomic analysis revealed that MMC-mediated ISR activation attenuates protein synthesis in Ctrl but not in KO mice. These findings underscore the critical role of PKR-dependent ISR activation and subsequent perturbation of proteostasis as central mechanisms driving PVOD pathogenesis and identifying PKR as a promising therapeutic target.

Authors

Amit Prabhakar, Rahul Kumar, Meetu Wadhwa, Abhilash Barpanda, Joseph Lyons, Asavari S. Gowda, Simren P. Gupta, Ananyaa Arvind, Prajakta Ghatpande, Arun P. Wiita, Brian B. Graham, Giorgio Lagna, Akiko Hata

Differential pathology and susceptibility to MBNL loss across muscles in myotonic dystrophy mouse models

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Abstract

There are two subtypes of myotonic dystrophy, DM1 and DM2, each caused by repeat expansion mutations. The leading pathogenic mechanism is RNA mediated toxicity whereby (C)CUG expansions sequester the muscleblind-like (MBNL) family of RNA binding proteins. However, key differences exist in muscle involvement patterns and histopathology between DM1 and DM2. The cause of these disparities both in how the muscles are affected within each disease and between the two diseases is unknown, and it is unclear if current DM mouse models recapitulate these differences or develop differential muscle susceptibility. Here, we examined the expression of disease-relevant genes across healthy human muscles from a transcriptomic atlas and collected a series of muscles from Mbnl knockout mice to evaluate characteristic histologic and molecular features of DM pathology. Our results indicate that MBNL loss discordantly affects muscles, likely through a splicing independent mechanism, and results in a fiber atrophy profile more like DM1 than DM2. These findings point to a predominant role for MBNL loss in muscle pattern involvement in DM1, provide further evidence for additional DM2 pathomechanisms, and have important implications for muscle choice when performing analyses in new mouse models and evaluating therapeutic modalities and biomarkers.

Authors

Mackenzie L. Davenport, Amaya Fong, Gloria Montoya-Vazquez, Maria Fernanda Alves de Moura, Jodi L. Bubenik, Maurice S. Swanson

Atrial Fibroblast-Derived Macrophage Migration Inhibitory Factor Promotes Atrial Macrophage Accumulation in Postoperative Atrial Fibrillation

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Abstract

Authors

Joshua A. Keefe, Jose Alberto Navarro-Garcia, Shuai Zhao, Mihail G. Chelu, Xander H.T. Wehrens

Photon and particle radiotherapy induce redundant modular chemotaxis of human lymphocytes

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Abstract

Radiotherapy triggers chemokine release and leukocyte infiltration in pre-clinical models through activation of the senescence-associated secretory phenotype (SASP). However, effects of irradiation on senescence and SASP in human tissue and in the context of particle radiotherapy remain unclear. Here, we analyzed chemokine patterns after radiotherapy of human pancreatic tumors and cancer cell lines. We show that irradiated tumor cells co-express SASP chemokines in defined modules. These chemokine modules correlated with infiltration of distinct leukocyte subtypes expressing cognate receptors. We developed a patient-derived pancreatic tumor explant system, which confirmed our identified radiation-induced chemokine modules. Chemokine modules were partially conserved in cancer cells in response to photon and particle irradiation showing a dose-dependent plateau effect and induced subsequent migration of NK and T cell populations. Hence, our work reveals redundant interactions of cancer cells and immune cells in human tissue, suggesting that targeting multiple chemokines is required to efficiently perturb leukocyte infiltration after photon or particle radiotherapy.

Authors

Joscha A. Kraske, Michael M. Allers, Aleksei Smirnov, Bénédicte Lenoir, Azaz Ahmed, Meggy Suarez-Carmona, Mareike Hampel, Damir Krunic, Alexandra Tietz-Dalfuß, Tizian Beikert, Jonathan M. Schneeweiss, Stephan Brons, Dorothee Albrecht, Thuy Trinh, Muzi Liu, Nathalia A. Giese, Christin Glowa, Jakob Liermann, Ramon Lopez Perez, Dirk Jäger, Jürgen Debus, Niels Halama, Peter E. Huber, Thomas Walle

Urine Proteomic Signatures of Kidney Function Decline after Hospitalization

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Abstract

BACKGROUND. Urine proteomics may provide mechanistic insights on why patients experience a higher risk of kidney function decline after hospitalization. METHDOS. In 174 patients with and without acute kidney injury (AKI) from the Assessment, Serial Evaluation, and Subsequent Sequelae in AKI (ASSESS-AKI) cohort, we used Olink to profile 2783 urine proteins collected at 3 months post-hospitalization and determined their association with estimated glomerular filtration rate (eGFR) decline during median [IQR] of 5.1[4.0-6.0] years follow-up. In four independent cohorts including the Kidney Precision Medicine Project (KPMP), we determined if proteins were differentially expressed with AKI. We used weighted correlation network analysis to determine proteins’ cellular enrichment in the kidney transcriptome (single-cell and spatial transcriptomics) in patients with AKI receiving research kidney biopsy. RESULTS. We identified 387 and 10 proteins associated with faster and slower eGFR decline, respectively, most of which were differentially expressed in patients at the time of AKI. Among these proteins, 283 (71%) were expressed by kidney cells in participants with AKI from KPMP. The expression formed 3 clusters enriched in the proximal tubule, degenerative tubule and myeloid cells, and stromal cells, and correlated with histopathological features of AKI, such as tubular injury, interstitial inflammation, and fibrosis, respectively. CONCLUSION. Urinary proteins reflecting degenerative tubular injury, inflammation, and fibrosis are associated with eGFR decline in recently hospitalized patients. FUNDING. The Kidney Precision Medicine Project (KPMP) is supported by the National Institute of Diabetes and Digestive Kidney Diseases (NIDDK) through the following grantsU01DK133081, U01DK133091, U01DK133092, U01DK133093, U01DK133095, U01DK133097, U01DK114866, U01DK114908, U01DK133090, U01DK133113, U01DK133766, U01DK133768, U01DK114907, U01DK114920, U01DK114923, U01DK114933, U24DK114886, UH3DK114926, UH3DK114861, UH3DK114915, and UH3DK114937 We gratefully acknowledge the essential contributions of our patient participants and support of the American public though their tax dollars. SM is supported by NIDDK Grant K23DK128358.

Authors

Yumeng Wen, Steven Menez, Heather Thiessen Philbrook, Dennis Moledina, Steven G. Coca, Jiashu Xue, James Kaufman, Vernon Chinchillil, Paul L. Kimmel, T. Alp Ikizler, Chi-yuan Hsu, Tanika Kelly, Ana Ricardo, Jonathan Himmelfarb, Chirag R. Parikh

Normal Treg homeostasis and suppressive function require both FOXP1 and FOXP4

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Abstract

FOXP3+ Treg cells are critical for immune tolerance. Genetic deletion of the Forkhead domain containing proteins of the FOXP-subfamily member FOXP1 from Tregs results in impaired function associated with reduced CD25 expression and IL-2 signaling, but to date the only other FOXP family member expressed in Tregs, FOXP4, has been minimally studied. To investigate the potential functional interactions among FOXP family members in Treg cells, we specifically deleted Foxp1, Foxp4 or both in FOXP3+ committed Treg cells in mice. Our findings show that mice with combined, but not individual, deficiency in FOXP1 and FOXP4 exhibit lymphoproliferation, inflammation, autoimmunity, and early lethality. The combined absence of FOXP1 and FOXP4 in Tregs results in an activated/effector-like phenotype with compromised suppressive function in peripheral lymphoid organs, an enhanced germinal center response and proinflammatory cytokine production. We further show that FOXP1 and FOXP4 bind to Il2ra promoter regions to regulate CD25 expression in Tregs. Through pairwise comparison among mouse strains with Treg specific deletion of Foxp1, Foxp4 or both, our findings indicate a non-redundant but insufficient role of FOXP4 in Treg cell function.

Authors

Dachuan Dong, Vishal J. Sindhava, Ananthakrishnan Ganesan, Martin S. Naradikian, Tom L. Stephen, Andrew Frisch, Kristen M. Valentine, Elizabeth Buza, Karla R. Wiehagen, Michael P. Cancro, Edward E. Morrisey, Haley Tucker, Katrina K. Hoyer, Purvesh Khatri, Jonathan S. Maltzman

Longitudinal single-cell analysis of glucagon-like peptide-2 treatment in the patients with short bowel syndrome

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Abstract

BACKGROUND. Glucagon-like peptide-2 (GLP-2) analogs are used clinically to enhance nutrient absorption in patients with short bowel syndrome (SBS); however, the precise mechanism remains unclear. To address this, the study aimed to clarify the dynamics of intestinal epithelial cells and immune cells in patients with SBS treated with GLP-2 analogs. METHODS. Five male patients diagnosed with SBS, all of whom received treatment with the GLP-2 analog teduglutide, were included in the study. We conducted longitudinal single-cell RNA sequencing (scRNA-seq) analysis of intestinal tissue from SBS patients over a year, integrating microbiome composition analysis. RESULTS. After treatment, the alpha diversity of the gut microbiome increased, indicating a more varied microbial environment. ScRNA-seq analysis revealed a reduction of T helper 2 cells and an increase in regulatory T (Treg) cells, suggesting a shift towards an immunoregulatory intestinal environment. Additionally, nutrient-absorbing enterocyte-Top2 and middle clusters expanded, enhancing the absorption capacity, whereas major histocompatibility complex class I/II-expressing enterocyte-Top1 cells declined, potentially modulating immune responses. CONCLUSION. The study findings indicate that GLP-2 analogs reshape intestinal immunity and microbiota, fostering a less inflammatory environment while promoting nutrient uptake efficiency. These insights offer a deeper understanding of the role of GLP-2 analogs in gut adaptation and provide a foundation for refining clinical strategies for SBS treatment. FUNDING. This work was supported by Sakaguchi Memorial Foundation, Grants-in-Aid from the Japanese Society for the Promotion of Science (JSPS) (21K18272, 23H03665, 23H02899, 23K27590, 25K22627, 23K08037), JST FOREST(21457195), and the Takeda Japan Medical Office Funded Research Grant 2022.

Authors

Yumi Kudo, Kentaro Miyamoto, Shohei Suzuki, Akihiko Chida, Anna Tojo, Mai Hasegawa, Arina Shigehara, Ikuko Koya, Yoshinari Ando, Masayasu Sato, Aya Kondo, Tomoko Kumagai, Harunori Deguchi, Yoshiki Sugiyama, Yoko Ito, Koji Shirosaki, Satoko Yamagishi, Yutaro Maeda, Hiroki Kanamori, Motohiro Kano, Mototoshi Kato, Hanako Tsujikawa, Yusuke Yoshimatsu, Kaoru Takabayashi, Koji Okabayashi, Takanori Kanai, Naoki Hosoe, Motohiko Kato, Jonathan Moody, Chung-Chau Hon, Tatsuo Kuroda, Yohei Yamada, Akihiro Fujino, Tomohisa Sujino

A ratiometric catalog of protein isoform shifts in the cardiac fetal gene program

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Abstract

Pathological cardiac remodeling is associated with the reactivation of fetal genes, yet the extent of the heart’s fetal gene program and its impact on proteome compositions remain incompletely understood. Here, using a new proteome-wide protein ratio quantification strategy with mass spectrometry, we identify pervasive isoform usage shifts in fetal and postnatal mouse hearts, involving 145 pairs of highly homologous paralogs and alternative splicing-derived isoform proteins. Proteome-wide ratio comparisons readily rediscover hallmark fetal gene signatures in muscle contraction and glucose metabolism pathways, while revealing novel isoform usage in mitochondrial and gene expression proteins, including PPA1/PPA2, ANT1/ANT2, and PCBP1/PCBP2 switches. Paralogs with differential fetal usage tend to be evolutionarily recent, consistent with functional diversification. Alternative splicing adds another rich source of fetal isoform usage differences, involving PKM M1/M2, GLS-1 KGA/GAC, PDLIM5 long/short, and other spliceoforms. When comparing absolute protein proportions, we observe a partial reversion toward fetal gene usage in pathological hearts. In summary, we present a ratiometric catalog of paralogs and spliceoform pairs in the cardiac fetal gene program. More generally, the results demonstrate the potential of applying the proteome-wide ratio test concept to discover new regulatory modalities beyond differential gene expression.

Authors

Yu Han, Shaonil Binti, Sara A. Wennersten, Boomathi Pandi, Dominic C.M. Ng, Edward Lau, Maggie P.Y. Lam

Transgenic augmentation of erythroferrone in mice ameliorates anemia in adenine-induced chronic kidney disease

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Abstract

Anemia is a common and disabling complication of chronic kidney disease (CKD). Current therapies can be burdensome, and full correction of anemia is limited by cardiovascular side effects. New approaches that may offer additional therapeutic options are needed. We explored the anti-anemic effects of erythroferrone, an erythroid hormone that induces iron mobilization by suppressing the master iron-regulatory hormone hepcidin. In a preclinical murine model of adenine-induced CKD, transgenic augmentation of erythroferrone mobilized iron, increased hemoglobin concentrations by approximately 2 g/dl, and modestly improved renal function without affecting systemic or renal inflammation, fibrosis, or markers of mineral metabolism. This study supports the concept that therapeutic augmentation of erythroferrone is a promising approach for alleviating CKD-associated anemia.

Authors

Brian Czaya, Joseph D. Olivera, Moya Zhang, Amber Lundin, Christian D. Castro Andrade, Grace Jung, Mark R. Hanudel, Elizabeta Nemeth, Tomas Ganz

BLIMP-1 and CEACAM1 cooperatively regulate human Treg homeostasis and function to control xenogeneic GVHD

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Abstract

Regulatory T cells (Tregs) are essential for peripheral tolerance and depend on TCR and IL-2R signaling for their homeostasis and function. In mice, IL-2-dependent BLIMP-1 contributes to Treg homeostasis. BLIMP-1 is a major transcriptional hub in human Tregs, but its mechanisms of action remain undefined. Here, using CRISPR/Cas9 ablation, we show that BLIMP-1 limits human Treg proliferation, but supports IL-10, CTLA4, several immune checkpoints, including CEACAM1, and Treg functional activity. BLIMP-1 restrains Treg expansion to IL-2 by downregulating CD25 and IL-2R signaling, and by enhancing CEACAM1 expression, which in turn inhibits responsiveness to CD3/CD28 signaling and activation of mTOR. Prolonged IL-2R signaling optimizes BLIMP-1 expression, supporting chromosomal opening of CEACAM1 to increased CEACAM1 expression through STAT5- and BLIMP-1-driven enhancers. Correspondingly, CEACAM1 is highly induced on Tregs from autoimmune patients undergoing low-dose IL-2 therapy, and these Tregs showed reduced proliferation. A humanized mouse model of xenogeneic graft versus host disease demonstrates that BLIMP-1 normally promotes, while CEACAM1 restrains, Treg suppressive activity. Collectively, our findings reveal that BLIMP-1 and CEACAM1 function in an IL-2-dependent feedback loop to restrain Treg proliferation and affect suppressive function. CEACAM1 also acts as a highly selective biomarker of IL-2R signaling in human T cells.

Authors

Ying Ding, Aixin Yu, Milos Vujanac, Sabrina N. Copsel, Alejandro Moro, Luis Nivelo, Molly Dalzell, Nicolas Tchitchek, Michelle Rosenzwajg, Alejandro V. Villarino, Robert B. Levy, David Klatzmann, Thomas R. Malek