In response to liver injury, hepatic stellate cells activate and acquire proliferative and contractile features. The regression of liver fibrosis appears to involve the clearance of activated hepatic stellate cells, either by apoptosis or by reversion towards a quiescent-like state, a process denominated deactivation. Thus, deactivation of active hepatic stellate cells has emerged as a novel and promising therapeutic approach for liver fibrosis. However, our knowledge of the master regulators involved in the de/activation of fibrotic hepatic stellate cells is still limited. The transcription factor GATA4 has been previously shown to play an important role in embryonic hepatic stellate cells quiescence. In this work, we show that lack of GATA4 in adult mice causes hepatic stellate cell activation and consequently, liver fibrosis. During regression of liver fibrosis, Gata4 is reexpressed in deactivated hepatic stellate cells. Overexpression of Gata4 in hepatic stellate cells promotes liver fibrosis regression in CCl4-treated mice. GATA4 induces changes in the expression of fibrogenic and antifibrogenic genes promoting hepatic stellate cell deactivation. Finally, we show that GATA4 directly represses EPAS1 transcription in hepatic stellate cells and that stabilization of the HIF2α protein in hepatic stellate cells leads to liver fibrosis.
Noelia Arroyo, Laura Villamayor, Irene Díaz, Rita Carmona, Mireia Ramos-Rodríguez, Ramon Muñoz-Chapuli, Lorenzo Pasquali, Miguel G. Toscano, Franz Martin, David A. Cano, Anabel Rojas
Glucagon-like peptide-1 receptor agonists (GLP-1RA) are used to treat diabetes and obesity and reduce rates of major cardiovascular events such as stroke and myocardial infarction. Nevertheless, the identity of GLP-1R-expressing cell types mediating the cardiovascular benefits of GLP-1RA remains incompletely characterized. Herein, we investigated the importance of murine Glp1r expression within endothelial and hematopoietic cells. Mice with targeted inactivation of the Glp1r in Tie2+ cells exhibited reduced levels of Glp1r mRNA transcripts in aorta, liver, spleen, blood and gut. Glp1r expression in bone marrow cells was very low, and not further reduced in Glp1rTie2-/- mice. The GLP-1RA semaglutide reduced the development of atherosclerosis induced by viral PCSK9 expression in both Glp1rTie2+/+ and Glp1rTie2-/- mice. Hepatic Glp1r mRNA transcripts were reduced in Glp1rTie2-/- mice and liver Glp1r expression was localized to γδ T cells. Moreover, semaglutide reduced hepatic Tnf, Abcg1, Tgfb1, Cd3g, Ccl2, and Il2 expression, triglyceride content and collagen accumulation in high fat high cholesterol (HFHC) diet-fed Glp1rTie2+/+ but not Glp1rTie2-/- mice. Collectively, these findings demonstrate that Tie2+ endothelial or hematopoietic cell GLP-1Rs are dispensable for the anti-atherogenic actions of GLP-1RA, whereas Tie2-targeted GLP-1R+ cells are required for a subset of the anti-inflammatory actions of semaglutide in the liver.
Brent McLean, Chi Kin Wong, Kiran Deep Kaur, Randy J. Seeley, Daniel J. Drucker
Ischemic retinopathies including diabetic retinopathy are major causes of blindness. While neurons and Müller glia are recognized as important regulators of reparative and pathologic angiogenesis, the role of mononuclear phagocytes (MPs), such as microglia/macrophages, is unclear, particularly microglia, the resident retinal immune cells. Here we found microglial/macrophage activation in human diabetic retinopathy, especially in neovessels from human neovascular membranes in proliferative retinopathy, including TNF-α expression. There was similar activation in the mouse oxygen-induced retinopathy (OIR) model of ischemia-induced neovascularization. Glucagon-like peptide-1 receptor (GLP-1R) agonists are in clinical use for glycemic control in diabetes and are also known to modulate microglia. We investigated the effect of a long-acting GLP-1R agonist, NLY01. Following intravitreal administration, NLY01 selectively localized to MPs in OIR retina. NLY01 modulated MP but not retinal endothelial cell viability, apoptosis, and tube formation in vitro. In OIR, NLY01 treatment inhibited MP infiltration and activation, including microglia/macrophage expression of cytokines in vivo. NLY01 significantly suppressed global induction of retinal inflammatory cytokines, promoted reparative angiogenesis, and suppressed pathologic retinal neovascularization. Collectively, these findings indicate the important role of microglia/macrophages in regulation of retinal vascularization in ischemia and suggest modulation of MPs as a new treatment strategy for ischemic retinopathies.
Lingli Zhou, Zhenhua Xu, Yumin Oh, Rico Gamuyao, Grace Lee, Yangyiran Xie, Hongkwan Cho, Seulki Lee, Elia J. Duh
Medulloblastoma (MB), one of the most malignant brain tumors of childhood, comprises distinct molecular subgroups, with p53 mutant sonic hedgehog (SHH)-activated MB patients having a very severe outcome that is associated with unfavorable histological large cell/anaplastic (LC/A) features. To identify the molecular underpinnings of this phenotype, we analyzed a large cohort of MBs developing in p53-deficient Ptch+/- SHH mice that, unexpectedly, showed LC/A traits that correlated with mechanistic Target Of Rapamycin Complex 1 (mTORC1) hyperactivation. Mechanistically, mTORC1 hyperactivation was mediated by a decrease in the p53-dependent expression of mTORC1 negative regulator Tsc2. Ectopic mTORC1 activation in mouse MB cancer stem cells (CSCs) promoted the in vivo acquisition of LC/A features and increased malignancy; accordingly, mTORC1 inhibition in p53-mutant Ptch+/- SHH MBs and CSC-derived MBs resulted in reduced tumor burden and aggressiveness. Most remarkably, mTORC1 hyperactivation was detected only in p53-mutant SHH MB patients’ samples and treatment with rapamycin of a human preclinical model phenocopying this subgroup decreased tumor growth and malignancy. Thus, mTORC1 may act as a specific druggable target for this subset of SHH MB, resulting in the implementation of a stringent risk stratification and in the potentially rapid translation of this precision medicine approach into the clinical setting.
Valentina Conti, Manuela Cominelli, Valentina Pieri, Alberto L. Gallotti, Ilaria Pagano, Matteo Zanella, Stefania Mazzoleni, Flavia Pivetta, Monica Patanè, Giulia M. Scotti, Ignazio S. Piras, Bianca Pollo, Andrea Falini, Alessio Zippo, Antonella Castellano, Roberta Maestro, Pietro L. Poliani, Rossella Galli
Immune cells exhibit low-level, constitutive signaling at rest (tonic signaling). Such tonic signals are required for fundamental processes, including the survival of B lymphocytes, but when elevated by genetic or environmental causes can lead to autoimmunity. Events that control ongoing signal transduction are therefore tightly regulated by submembrane cytoskeletal polymers like filamentous (F)-actin. The actin-binding proteins that underpin the process, however, are poorly described. By investigating patients with ARPC1B-deficiency, we report that ARPC1B-containing ARP2/3 complexes are stimulated by Wiskott Aldrich Syndrome protein (WASP) to nucleate the branched actin networks that control tonic signaling from the B cell receptor (BCR). Despite an upregulation of ARPC1A, ARPC1B-deficient cells were not capable of WASP-mediated nucleation by ARP2/3 and this caused the loss of WASP-dependent structures including podosomes in macrophages and lamellipodia in B cells. In the B cell compartment, ARPC1B-deficiency also led to weakening of the cortical F-actin cytoskeleton that normally curtails the diffusion of B cell receptors and ultimately resulted in increased tonic lipid signaling, oscillatory calcium release from the endoplasmic reticulum (ER), and phosphorylated Akt. These events contributed to skewing the threshold for B cell activation in response to microbial associated molecular patterns (MAMPs). Thus, ARPC1B is critical for ARP2/3 complexes to control steady-state signaling of immune cells.
Gabriella Leung, Yuhuan Zhou, Philip Ostrowski, Sivakami Mylvaganam, Parastoo Boroumand, Daniel J. Mulder, Conghui Guo, Aleixo M. Muise, Spencer Freeman
Angiogenesis, a hallmark of cancer, is induced by vascular endothelial growth factor-A (VEGF). As a result, anti-VEGF therapy is commonly employed for cancer treatment. Recent studies have found that VEGF expression is also associated with immune suppression in cancer patients. This connection has been investigated in preclinical and clinical studies by evaluating the therapeutic effect of combining anti-angiogenic reagents with immune therapy. However, the mechanisms of how anti-VEGF strategies enhance immune therapy are not fully understood. We and others have shown selective elevation of VEGFR2 expression on tumor-associated myeloid cells in tumor-bearing animals. Here we investigated the function of VEGFR2+ myeloid cells in regulating tumor immunity and found VEGF induces an immunosuppressive phenotype in VEGFR2+ myeloid cells including directly upregulating the expression of programmed cell death 1-ligand 1 (PD-L1). Moreover, we found that VEGF blockade inhibits the immunosuppressive phenotype of VEGFR2+ myeloid cells, increases T cell activation and enhances the efficacy of immune checkpoint blockade. This study highlights the function of VEGFR2 on myeloid cells and provides mechanistic insight on how VEGF inhibition potentiates immune checkpoint blockade.
Yuqing Zhang, Huocong Huang, Morgan Coleman, Arturas Ziemys, Purva Gopal, Syed M. Kazmi, Rolf A. Brekken
Understanding the presence and durability of antibodies against SARS-CoV-2 in the airways is required to provide insights on the ability of individuals to neutralize the virus locally and prevent viral spread. Here, we longitudinally assessed both systemic and airway immune responses upon SARS-CoV-2 infection in a clinically well-characterized cohort of 147 infected individuals representing the full spectrum of COVID-19 severity; from asymptomatic infection to fatal disease. In addition, we evaluated how SARS-CoV-2 vaccination influenced the antibody responses in a subset of these individuals during convalescence as compared to naïve individuals. Not only systemic but also airway antibody responses correlated with the degree of COVID-19 disease severity. However, while systemic IgG levels were durable for up to 8 months, airway IgG and IgA had declined significantly within 3 months. After vaccination, there was an increase in both systemic and airway antibodies, in particular IgG, often exceeding the levels found during acute disease. In contrast, naïve individuals showed low airway antibodies after vaccination. In the former COVID-19 patients, airway antibody levels were significantly elevated after the boost vaccination, highlighting the importance of prime and boost vaccination also for previously infected individuals to obtain optimal mucosal protection.
Alberto Cagigi, Meng Yu, Björn Österberg, Julia Svensson, Sara Falck-Jones, Sindhu Vangeti, Eric Åhlberg, Lida Azizmohammadi, Anna Warnqvist, Ryan Falck-Jones, Pia C. Gubisch, Mert Ödemis, Farangies Ghafoor, Mona Eisele, Klara Lenart, Max Bell, Niclas Johansson, Jan Albert, Jörgen Sälde, Deleah D. Pettie, Michael P. Murphy, Lauren Carter, Neil P. King, Sebastian Ols, Johan Normark, Clas Ahlm, Mattias N. Forsell, Anna Färnert, Karin Loré, Anna Smed-Sörensen
BACKGROUND. Recessive dystrophic epidermolysis bullosa (RDEB) is a rare, devastating, and life-threatening inherited skin fragility disorder due to a lack of functional type VII collagen, for which no effective therapy exists. ABCB5-positive dermal mesenchymal stem cells (ABCB5+ MSCs) possess immunomodulatory capacities, a favorable skin homing potential and the ability to secrete type VII collagen. In a COL7A1–/– mouse model of RDEB, treatment with ABCB5+ MSCs markedly extended the animals’ lifespans. METHODS. In this international, multicentric, single-arm, phase I/IIa clinical trial, 16 patients (aged 4–36 years) enrolled into four age cohorts received three intravenous infusions of 2×106 ABCB5+ MSCs/kg on days 0, 17 and 35. Patients were followed up for 12 weeks regarding efficacy and 12 months regarding safety. RESULTS. At 12 weeks, statistically significant median (IQR) reductions in the Epidermolysis Bullosa Disease Activity and Scarring Index activity (EBDASI activity) score of 13.0% (2.9%-30%; P = 0.049) and the Instrument for Scoring Clinical Outcome of Research for Epidermolysis Bullosa clinician (iscorEB c) score of 18.2% (4.1%-41.7%; P = 0.037) were observed. Reductions in itch and pain numerical rating scale scores were greatest on day 35, amounting to 37.5% (0.0%-42.9%; P = 0.033) and 25.0% (-8.4%-46.4%; P = 0.168), respectively. Three adverse events were considered related to the cell product, one mild lymphadenopathy and two hypersensitivity reactions. The latter two were serious but resolved without sequelae shortly after withdrawal of treatment. CONCLUSION. This trial demonstrates good tolerability, manageable safety and potential efficacy of intravenous ABCB5+ MSCs as a readily available disease-modifying therapy for RDEB and provides a rationale for further clinical evaluation. TRIAL REGISTRATION. clinicaltrials.gov NCT03529877; EudraCT 2018-001009-98 FUNDING. The trial was sponsored by RHEACELL GmbH & Co. KG, Heidelberg, Germany. Contributions by NY Frank and MH Frank to this work were supported by the National Institutes of Health (NIH)/National Eye Institute (NEI) grants RO1EY025794 and R24EY028767.
Dimitra Kiritsi, Kathrin Dieter, Elke Niebergall-Roth, Silvia Fluhr, Cristina Daniele, Jasmina Esterlechner, Samar Sadeghi, Seda Ballikaya, Leoni Erdinger, Franziska Schauer, Stella Gewert, Martin Laimer, Johann W. Bauer, Alain Hovnanian, Giovanna Zambruno, May El Hachem, Emmanuelle Bourrat, Maria Papanikolaou, Gabriela Petrof, Sophie Kitzmüller, Christen L. Ebens, Markus H. Frank, Natasha Y. Frank, Christoph Ganss, Anna E. Martinez, John A. McGrath, Jakub Tolar, Mark A. Kluth
Lung allograft rejection results in the accumulation of low molecular weight hyaluronic acid (LMW-HA), which further propagates inflammation and tissue injury. We have previously shown that therapeutic lymphangiogenesis in a murine model of lung allograft rejection reduced tissue LMW-HA and was associated with improved transplant outcomes. Herein we investigated the use of 4-Methylumbelliferone, a known inhibitor of HA synthesis, to alleviate acute allograft rejection in a murine model of lung transplantation. We found that treating mice with 4MU from day 20-30 post-transplant was sufficient to significantly improve outcomes, characterized by a reduction in T-cell mediated lung inflammation, LMW-HA content, and improved pathology scores. In vitro, 4MU directly attenuated activation, proliferation, and differentiation of naïve CD4+ T-cells into Th1 cells. As 4MU has already been demonstrated to be safe for human use, we believe examining 4MU for the treatment of acute lung allograft rejection may be of clinical significance.
Jewel Imani, Kaifeng Liu, Ye Cui, Jean-Pierre Assaker, Junwen Han, Auyon J. Ghosh, Julie Ng, Shikshya Shrestha, Anthony M. Lamattina, Pierce H. Louis, Anne Hentschel, Anthony J. Esposito, Ivan O. Rosas, Xiaoli Liu, Mark A. Perrella, Jamil Azzi, Gary Visner, Souheil El-Chemaly
Patients with acute leukemia who are unable to achieve complete remission prior to allogeneic hematopoietic stem cell transplantation (SCT) have dismal outcomes with relapse rates well in excess of 60%. Haplo-identical SCT (haplo-SCT) may allow enhanced graft-versus-leukemia (GVL) effects by virtue of HLA class I/II donor-host disparities but typically requires intensive immune-suppression with post-transplant cyclophosphamide (PT-Cy) to prevent lethal graft-versus-host disease (GVHD). Here we demonstrate in preclinical models that glucocorticoid administration from day -1 to +5 inhibits alloantigen presentation by professional recipient antigen presenting cells in the gastrointestinal tract and prevents donor T-cell priming and subsequent expansion therein. In contrast, direct glucocorticoid signaling of donor T-cells promotes chemokine and integrin signatures permissive of preferential circulation and migration into the bone marrow, promoting donor T-cell residency. This results in significant reductions in GVHD whilst promoting potent GVL effects (relapse in recipients receiving glucocorticoids, vehicle or PT-Cy was 12%, 56% and 100% respectively). Intriguingly, patients with acute myeloid leukemia not in remission that received unmanipulated haplo-SCT and peri-transplant glucocorticoids also had an unexpectedly low relapse rate at 1 year (32%: 95% CI, 18%-47%) with high overall survival at 3 years (58%: 95% CI, 38-74%). These data highlight a potentially simple and effective approach to prevent relapse in patients with otherwise incurable leukemia that could be studied in prospective randomized trials.
Takayuki Inoue, Motoko Koyama, Katsuji Kaida, Kazuhiro Ikegame, Kathleen S. Ensbey, Luke Samson, Shuichiro Takahashi, Ping Zhang, Simone A. Minnie, Satoshi Maruyama, Shinichi Ishii, Takashi Daimon, Takahiro Fukuda, Hirohisa Nakamae, Takahide Ara, Yumiko Maruyama, Ken Ishiyama, Tatsuo Ichinohe, Yoshiko Atsuta, Bruce R. Blazar, Scott N. Furlan, Hiroyasu Ogawa, Geoffrey R. Hill
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