InVivoMAb anti-mouse IL-6R

• Cancer Research
,
• Immunology and Microbiology

Establishment and validation of an immune-related nomogram for the prognosis of pancreatic adenocarcinoma.

In Scientific Reports on 18 April 2025 by Wang, K., Lu, Y., et al.

Pancreatic adenocarcinoma (PDAC) is a highly aggressive neoplasm characterized by limited therapeutic options, particularly in the realm of immunotherapy. This study aims to improve prognosis prediction to guide therapeutic decision-making, and to identify novel targets for immunotherapy of PDAC. We conducted Cox and LASSO regression analyses to develop immune-related gene signature and corresponding nomogram, and the robustness of these signatures was demonstrated using multiple approaches. Additionally, CIBERSORT, ESTIMATE, and xCell algorithms were utilized to assess immune cell infiltration, with experimental validation performed though qPCR. An immune-related gene signature consisting of 18 genes, and the prognostic nomogram was established with superior performance compared to the conventional staging system. Key parameters incorporated into the nomogram included the gene signature, tumor stage, and postoperative treatment. Patients identified as high-risk exhibited an anti-inflammatory tumor microenvironment, characterized by an increase in M2-like tumor-associated macrophages and heightened tumor purity. Notably, the expression of interleukin 6 receptor (IL6R) in PDAC was predominantly derived from macrophages and was significantly associated with patient survival outcomes. Furthermore, attenuated IL-6/IL-6R signaling was found to promote M2-like macrophage differentiation. This study successfully established an immune-related gene signature and a robust nomogram for predicting clinical outcomes in patients with PDAC. Furthermore, we identified IL6R as a promising target for future immunotherapeutic strategies. © 2025. The Author(s).

Enhanced Interleukin 6 Trans-Signaling Modulates Disease Process in Amyotrophic Lateral Sclerosis Mouse Models.

In Brain Sciences on 17 January 2025 by Milligan, C., Cowley, D. O., et al.

Background/Objectives: Charcot first described ALS in 1869, but the specific mechanisms that mediate the disease pathology are still not clear. Intense research efforts have provided insight into unique neuroanatomical regions, specific neuronal populations and genetic associations for ALS and other neurodegenerative diseases; however, the experimental results also suggest a convergence of these events to common toxic pathways. We propose that common toxic pathways can be therapeutically targeted, and this intervention will be effective in slowing progression and improving patient quality of life. Here, we focus on understanding the role of IL6 trans-signaling in ALS disease processes. Methods: We leveraged unique mouse models of IL6 trans-signaling that we developed that recapitulate the production of active sIL6R in a genotypic and quantitative fashion observed in humans. Given that the SOD1 transgenic mouse is one of the most highly studied and characterized models of ALS, we bred SOD1G93A mice with IL6R trans-signaling mice to determine how enhanced trans-signaling influenced symptom onset and pathological processes, including neuromuscular junction (NMJ) denervation, glial activation and motoneuron (MN) survival. Results: The results indicate that in animals with enhanced trans-signaling, symptom onset and pathological processes were accelerated, suggesting a role in disease modification. Administration of an IL6R functional blocking antibody failed to alter accelerated symptom onset and disease progression. Conclusions: Future work to investigate the site-specific influence of enhanced IL6 trans-signaling and the tissue-specific bioavailability of potential therapeutics will be necessary to identify targets for precise therapeutic interventions that may limit disease progression in the 60% of ALS patients who inherit the common Il6R Asp358Ala variant.

• Cancer Research
,
• Cell Biology
,
• Immunology and Microbiology

Targeting cancer-associated fibroblast autophagy renders pancreatic cancer eradicable with immunochemotherapy by inhibiting adaptive immune resistance.

In Autophagy on 1 June 2024 by Zhang, X., Lao, M., et al.

Accumulating evidence suggests that cancer-associated fibroblast (CAF) macroautophagy/autophagy is crucial in tumor development and may be a therapeutic target for pancreatic ductal adenocarcinoma (PDAC). However, the role of CAF autophagy during immune surveillance and cancer immunotherapy is unclear. The present study revealed that the inhibition of CAF autophagy suppresses in vivo tumor development in immune-deficient xenografts. This deletion compromises anti-tumor immunity and anti-tumor efficacy both in vitro and in vivo by upregulating CD274/PDL1 levels in an immune-competent mouse model. A block in CAF autophagy reduced the production of IL6 (interleukin 6), disrupting high desmoplastic TME and decreasing USP14 expression at the transcription level in pancreatic cancer cells. We further identify USP14 as the post-translational factor responsible for downregulating CD274 expression by removing K63 linked-ubiquitination at the K280 residue. Finally, chloroquine diphosphate-loaded mesenchymal stem cell (MSC)-liposomes, by accurately targeting CAFs, inhibited CAF autophagy, improving the efficacy of immunochemotherapy to combat pancreatic cancer.Abbreviation: AIR: adaptive immune resistance; ATRA: all-trans-retinoicacid; CAF: cancer-associated fibroblast; CD274/PDL1: CD274 molecule; CM: conditioned medium; CQ: chloroquine diphosphate; CyTOF: Mass cytometry; FGF2/bFGF: fibroblast growth factor 2; ICB: immune checkpoint blockade; IF: immunofluorescence; IHC: immunohistochemistry; IP: immunoprecipitation; MS: mass spectrometer; MSC: mesenchymal stem cell; PDAC: pancreatic ductal adenocarcinoma; TEM: transmission electron microscopy; TILs: tumor infiltrating lymphocytes; TME: tumor microenvironment; USP14: ubiquitin specific peptidase 14.

• Mus musculus (House mouse)
,
• COVID-19
,
• Immunology and Microbiology
,
• IHC

Two new and effective food-extracted immunomodulatory agents exhibit anti-inflammatory response activity in the hACE2 acute lung injury murine model of COVID-19.

In Frontiers in Immunology on 29 May 2024 by Liu, S., Wang, B., et al.

The coronavirus disease 2019 (COVID-19) spread rapidly and claimed millions of lives worldwide. Acute respiratory distress syndrome (ARDS) is the major cause of COVID-19-associated deaths. Due to the limitations of current drugs, developing effective therapeutic options that can be used rapidly and safely in clinics for treating severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections is necessary. This study aims to investigate the effects of two food-extracted immunomodulatory agents, ajoene-enriched garlic extract (AGE) and cruciferous vegetables-extracted sulforaphane (SFN), on anti-inflammatory and immune responses in a SARS-CoV-2 acute lung injury mouse model. In this study, we established a mouse model to mimic the SARS-CoV-2 infection acute lung injury model via intratracheal injection of polyinosinic:polycytidylic acid (poly[I:C]) and SARS-CoV-2 recombinant spike protein (SP). After the different agents treatment, lung sections, bronchoalveolar lavage fluid (BALF) and fresh faeces were harvested. Then, H&E staining was used to examine symptoms of interstitial pneumonia. Flow cytometry was used to examine the change of immune cell populations. Multiplex cytokines assay was used to examine the inflammatory cytokines.16S rDNA high-throughput sequencing was used to examine the change of gut microbiome. Our results showed that AGE and SFN significantly suppressed the symptoms of interstitial pneumonia, effectively inhibited the production of inflammatory cytokines, decreased the percentage of inflammatory cell populations, and elevated T cell populations in the mouse model. Furthermore, we also observed that the gut microbiome of genus Paramuribaculum were enriched in the AGE-treated group. Here, for the first time, we observed that these two novel, safe, and relatively inexpensive immunomodulatory agents exhibited the same effects on anti-inflammatory and immune responses as neutralizing monoclonal antibodies (mAbs) against interleukin 6 receptor (IL-6R), which have been suggested for treating COVID-19 patients. Our results revealed the therapeutic ability of these two immunomodulatory agents in a mouse model of SARS-CoV-2 acute lung injury by promoting anti-inflammatory and immune responses. These results suggest that AGE and SFN are promising candidates for the COVID-19 treatment. Copyright © 2024 Liu, Wang, Chen, Wang, Liu, Zhao and Zhang.

• Mus musculus (House mouse)

Blockade of IL-6R prevents preterm birth and adverse neonatal outcomes.

In EBioMedicine on 1 December 2023 by Farías-Jofré, M., Romero, R., et al.

Preterm birth preceded by spontaneous preterm labour often occurs in the clinical setting of sterile intra-amniotic inflammation (SIAI), a condition that currently lacks treatment. Proteomic and scRNA-seq human data were analysed to evaluate the role of IL-6 and IL-1α in SIAI. A C57BL/6 murine model of SIAI-induced preterm birth was developed by the ultrasound-guided intra-amniotic injection of IL-1α. The blockade of IL-6R by using an aIL-6R was tested as prenatal treatment for preterm birth and adverse neonatal outcomes. QUEST-MRI evaluated brain oxidative stress in utero. Targeted transcriptomic profiling assessed maternal, foetal, and neonatal inflammation. Neonatal biometrics and neurodevelopment were tested. The neonatal gut immune-microbiome was evaluated using metagenomic sequencing and immunophenotyping. IL-6 plays a critical role in the human intra-amniotic inflammatory response, which is associated with elevated concentrations of the alarmin IL-1α. Intra-amniotic injection of IL-1α resembles SIAI, inducing preterm birth (7% vs. 50%, p = 0.03, Fisher's exact test) and neonatal mortality (18% vs. 56%, p = 0.02, Mann-Whitney U-test). QUEST-MRI revealed no foetal brain oxidative stress upon in utero IL-1α exposure (p > 0.05, mixed linear model). Prenatal treatment with aIL-6R abrogated IL-1α-induced preterm birth (50% vs. 7%, p = 0.03, Fisher's exact test) by dampening inflammatory processes associated with the common pathway of labour. Importantly, aIL-6R reduces neonatal mortality (56% vs. 22%, p = 0.03, Mann-Whitney U-test) by crossing from the mother to the amniotic cavity, dampening foetal organ inflammation and improving growth. Beneficial effects of prenatal IL-6R blockade carried over to neonatal life, improving survival, growth, neurodevelopment, and gut immune homeostasis. IL-6R blockade can serve as a strategy to treat SIAI, preventing preterm birth and adverse neonatal outcomes. NICHD/NIH/DHHS, Contract HHSN275201300006C. WSU Perinatal Initiative in Maternal, Perinatal and Child Health. Copyright © 2023. Published by Elsevier B.V.

• Mus musculus (House mouse)
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• Immunology and Microbiology
,
• Biochemistry and Molecular biology

In Cell Metabolism on 3 October 2023 by Becker, M., Joseph, S. S., et al.

PubMed

Muscle-residing regulatory T cells (Tregs) control local tissue integrity and function. However, the molecular interface connecting Treg-based regulation with muscle function and regeneration remains largely unexplored. Here, we show that exercise fosters a stable induction of highly functional muscle-residing Tregs with increased expression of amphiregulin (Areg), EGFR, and ST2. Mechanistically, we find that mice lacking IL6Rα on T cells (TKO) harbor significant reductions in muscle Treg functionality and satellite and fibro-adipogenic progenitor cells, which are required for muscle regeneration. Using exercise and sarcopenia models, IL6Rα TKO mice demonstrate deficits in Tregs, their functional maturation, and a more pronounced decline in muscle mass. Muscle injury models indicate that IL6Rα TKO mice have significant disabilities in muscle regeneration. Treg gain of function restores impaired muscle repair in IL6Rα TKO mice. Of note, pharmacological IL6R blockade in WT mice phenocopies deficits in muscle function identified in IL6Rα TKO mice, thereby highlighting the clinical implications of the findings. Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.

• Mus musculus (House mouse)
,
• Immunology and Microbiology

In eLife on 11 August 2023 by Jackson, W. D., Giacomassi, C., et al.

PubMed

Monocytes are heterogeneous innate effector leukocytes generated in the bone marrow and released into circulation in a CCR2-dependent manner. During infection or inflammation, myelopoiesis is modulated to rapidly meet the demand for more effector cells. Danger signals from peripheral tissues can influence this process. Herein we demonstrate that repetitive TLR7 stimulation via the epithelial barriers drove a potent emergency bone marrow monocyte response in mice. This process was unique to TLR7 activation and occurred independently of the canonical CCR2 and CX3CR1 axes or prototypical cytokines. The monocytes egressing the bone marrow had an immature Ly6C-high profile and differentiated into vascular Ly6C-low monocytes and tissue macrophages in multiple organs. They displayed a blunted cytokine response to further TLR7 stimulation and reduced lung viral load after RSV and influenza virus infection. These data provide insights into the emergency myelopoiesis likely to occur in response to the encounter of single-stranded RNA viruses at barrier sites. © 2023, Jackson, Giacomassi et al.

In Nat Cardiovasc Res on 1 June 2023 by Liu, W., Yalcinkaya, M., et al.

PubMed

Clonal hematopoiesis (CH) increases the risk of atherosclerotic cardiovascular disease possibly due to increased plaque inflammation. Human studies suggest that limitation of interleukin-6 (IL-6) signaling could be beneficial in people with large CH clones, particularly in TET2 CH. Here we show that IL-6 receptor antibody treatment reverses the atherosclerosis promoted by Tet2 CH, with reduction of monocytosis, lesional macrophage burden and macrophage colony-stimulating factor 1 receptor (CSF1R) expression. IL-6 induces expression of Csf1r in Tet2-deficient macrophages through enhanced STAT3 binding to its promoter. In mouse and human Tet2-deficient macrophages, IL-6 increases CSF1R expression and enhances macrophage survival. Treatment with the CSF1R inhibitor PLX3397 reversed accelerated atherosclerosis in Tet2 CH mice. Our study demonstrates the causality of IL-6 signaling in Tet2 CH accelerated atherosclerosis, identifies IL-6-induced CSF1R expression as a critical mechanism and supports blockade of IL-6 signaling as a potential therapy for CH-driven cardiovascular disease.

• Mus musculus (House mouse)
,
• Neuroscience

In BJA: British Journal of Anaesthesia on 1 December 2022 by Hu, J., Zhang, Y., et al.

PubMed

Interleukin-6 (IL-6), a pleiotropic cytokine with both degenerative and regenerative properties, is necessary and sufficient to provoke perioperative neurocognitive disorders after aseptic trauma in mice. IL-6 initiates its actions after binding to either membrane-bound IL-6 receptor α (mIL-6Rα) through classical signalling, or soluble IL-6 receptor (IL-6R) through trans-signalling; both signalling pathways require the transducer gp130. We investigated the site and type of IL-6 signalling that pertains in a tibial fracture aseptic trauma model of perioperative neurocognitive disorder. Wild-type or genetically altered adult mice that lacked molecules unique to either classical or trans-IL-6 signalling underwent tibial fracture under isoflurane anaesthesia. In separate cohorts, we assessed postoperative memory using a trace fear conditioning paradigm (72 h postoperatively), and post-receptor IL-6 signalling (24 h postoperatively) using phosphorylation of signal transducer and activator of transcription 3 (pSTAT3) in CA1 hippocampal neurones. Fracture healing was assessed at postoperative day 15 after inhibiting either both forms of IL-6 signalling with BE0047 or only trans-signalling with sgp130Fc. The surgical phenotype of memory decline (decrease in freezing in trace fear conditioning) and upregulated IL-6 signalling (pSTAT3) did not occur after pretreatment before surgery with either BE0047 or sgp130Fc, or after depleting gp130 from CA1 neurones. The surgical phenotype still occurred when IL-6Rα was depleted in either CA1 hippocampal neurones (freezing time, 38.9% [11.5%] vs 58.4% [12.3%]; pSTAT+ CA1 neurones, 31.7 [4.9] vs 7.0 [3.1]) or microglia (freezing time, 40.1% [13.9%] vs 65.2% [12.6%]; pSTAT+ CA1 neurones, 30.1 [5.5] vs 7.9 [3.2]). In global IL-6Rα-/- mice, hyper-IL-6, the trans-signalling agonist, produced the surgical phenotype when administered i.c.v. (freezing time, 42.4% [8.8%] vs 59.7% [10.4%]; pSTAT+ cells, 29.3 [4.3] vs 10.0 [4.4]). Bone-fracture healing (% of fracture callus comprised of new collagen) was significantly greater with sgp130Fc than with BE0047 (52.2% [8.3%] vs 39.7% [7.9%]). After orthopaedic trauma, IL-6 produces perioperative neurocognitive disorders through IL-6 trans-signalling in mouse CA1 neurones. Druggable targets of the trans-signalling pathway should be sought to reduce perioperative neurocognitive disorders while allowing the healing properties of classical IL-6 signalling. Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.

• Cancer Research
,
• Neuroscience

In Brain on 14 September 2022 by Perelroizen, R., Philosof, B., et al.

PubMed

Malignant brain tumours are the cause of a disproportionate level of morbidity and mortality among cancer patients, an unfortunate statistic that has remained constant for decades. Despite considerable advances in the molecular characterization of these tumours, targeting the cancer cells has yet to produce significant advances in treatment. An alternative strategy is to target cells in the glioblastoma microenvironment, such as tumour-associated astrocytes. Astrocytes control multiple processes in health and disease, ranging from maintaining the brain's metabolic homeostasis, to modulating neuroinflammation. However, their role in glioblastoma pathogenicity is not well understood. Here we report that depletion of reactive astrocytes regresses glioblastoma and prolongs mouse survival. Analysis of the tumour-associated astrocyte translatome revealed astrocytes initiate transcriptional programmes that shape the immune and metabolic compartments in the glioma microenvironment. Specifically, their expression of CCL2 and CSF1 governs the recruitment of tumour-associated macrophages and promotes a pro-tumourigenic macrophage phenotype. Concomitantly, we demonstrate that astrocyte-derived cholesterol is key to glioma cell survival, and that targeting astrocytic cholesterol efflux, via ABCA1, halts tumour progression. In summary, astrocytes control glioblastoma pathogenicity by reprogramming the immunological properties of the tumour microenvironment and supporting the non-oncogenic metabolic dependency of glioblastoma on cholesterol. These findings suggest that targeting astrocyte immunometabolic signalling may be useful in treating this uniformly lethal brain tumour. © The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

• Cancer Research
,
• Immunology and Microbiology

In Nature Communications on 25 August 2022 by Shen, H., Huang, F., et al.

PubMed

Therapeutic resistance to immune checkpoint blockers (ICBs) in melanoma patients is a pressing issue, of which tumor loss of IFN-γ signaling genes is a major underlying mechanism. However, strategies of overcoming this resistance mechanism have been largely elusive. Moreover, given the indispensable role of tumor-infiltrating T cells (TILs) in ICBs, little is known about how tumor-intrinsic loss of IFN-γ signaling (IFNγR1KO) impacts TILs. Here, we report that IFNγR1KO melanomas have reduced infiltration and function of TILs. IFNγR1KO melanomas harbor a network of constitutively active protein tyrosine kinases centered on activated JAK1/2. Mechanistically, JAK1/2 activation is mediated by augmented mTOR. Importantly, JAK1/2 inhibition with Ruxolitinib selectively suppresses the growth of IFNγR1KO but not scrambled control melanomas, depending on T cells and host TNF. Together, our results reveal an important role of tumor-intrinsic IFN-γ signaling in shaping TILs and manifest a targeted therapy to bypass ICB resistance of melanomas defective of IFN-γ signaling. © 2022. The Author(s).

In Science Translational Medicine on 20 July 2022 by Stancil, I. T., Michalski, J. E., et al.

PubMed

Chronic disease results from the failure of tissues to maintain homeostasis. In the lung, coordinated repair of the epithelium is essential for preserving homeostasis. In animal models and human lung disease, airway epithelial cells mobilize in response to lung injury, resulting in the formation of airway-like cysts with persistent loss of functional cell types and parenchymal architecture. Using live-cell imaging of human lung epithelial cultures and mouse precision-cut lung slices, we demonstrated that distal airway epithelia are aberrantly fluidized both after injury and in fibrotic lung disease. Through transcriptomic profiling and pharmacologic stimulation of epithelial cultures, we identified interleukin-6 (IL-6) signaling as a driver of tissue fluidization. This signaling cascade occurred independently of canonical Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling but instead was dependent on a downstream SRC family kinase (SFK)-yes-associated protein (YAP) axis. Airway epithelial-fibroblast cocultures revealed that the fibrotic mesenchyme acts as a source of IL-6 family cytokines, which drive airway fluidization. Inhibition of the IL-6-SFK-YAP cascade was sufficient to prevent fluidization in both in vitro and ex vivo models. Last, we demonstrated a reduction in fibrotic lung remodeling in mice through genetic or pharmacologic targeting of IL-6-related signaling. Together, our findings illustrate the critical role of airway epithelial fluidization in coordinating the balance between homeostatic lung repair and fibrotic airspace remodeling.

• Immunology and Microbiology

Single-cell analysis identifies the interaction of altered renal tubules with basophils orchestrating kidney fibrosis.

In Nature Immunology on 1 June 2022 by Doke, T., Abedini, A., et al.

Inflammation is an important component of fibrosis but immune processes that orchestrate kidney fibrosis are not well understood. Here we apply single-cell sequencing to a mouse model of kidney fibrosis. We identify a subset of kidney tubule cells with a profibrotic-inflammatory phenotype characterized by the expression of cytokines and chemokines associated with immune cell recruitment. Receptor-ligand interaction analysis and experimental validation indicate that CXCL1 secreted by profibrotic tubules recruits CXCR2+ basophils. In mice, these basophils are an important source of interleukin-6 and recruitment of the TH17 subset of helper T cells. Genetic deletion or antibody-based depletion of basophils results in reduced renal fibrosis. Human kidney single-cell, bulk gene expression and immunostaining validate a function for basophils in patients with kidney fibrosis. Collectively, these studies identify basophils as contributors to the development of renal fibrosis and suggest that targeting these cells might be a useful clinical strategy to manage chronic kidney disease. © 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.

• Neuroscience
,
• Mus musculus (House mouse)

In Antioxidants (Basel, Switzerland) on 16 December 2021 by López-Blanch, R., Salvador, R., et al.

PubMed

Oxidative stress has been proposed as a major mechanism of damage to motor neurons associated with the progression of amyotrophic lateral sclerosis (ALS). Astrocytes are the most numerous glial cells in the central nervous system and, under physiological conditions, protect neurons from oxidative damage. However, it is uncertain how their reactive phenotype may affect motor neurons during ALS progression. In two different ALS mouse models (SOD1G93A and FUS-R521C), we found that increased levels of proinflammatory interleukin 6 facilitate glutathione (GSH) release from the liver to blood circulation, which can reach the astrocytes and be channeled towards motor neurons as a mechanism of antioxidant protection. Nevertheless, although ALS progression is associated with an increase in GSH efflux from astrocytes, generation of reactive oxygen species also increases, suggesting that as the disease progresses, astrocyte-derived oxidative stress could be key to motor-neuron damage.

• In Vivo
,
• Mus musculus (House mouse)
,
• Cancer Research
,
• Immunology and Microbiology

In Nature Communications on 28 October 2021 by Bent, E. H., Millán-Barea, L. R., et al.

PubMed

Cytotoxic chemotherapeutics primarily function through DNA damage-induced tumor cell apoptosis, although the inflammation provoked by these agents can stimulate anti-cancer immune responses. The mechanisms that control these distinct effects and limit immunogenic responses to DNA-damage mediated cell death in vivo are currently unclear. Using a mouse model of BCR-ABL+ B-cell acute lymphoblastic leukemia, we show that chemotherapy-induced anti-cancer immunity is suppressed by the tumor microenvironment through production of the cytokine IL-6. The chemotherapeutic doxorubicin is curative in IL-6-deficient mice through the induction of CD8+ T-cell-mediated anti-cancer responses, while moderately extending lifespan in wild type tumor-bearing mice. We also show that IL-6 suppresses the effectiveness of immune-checkpoint inhibition with anti-PD-L1 blockade. Our results suggest that IL-6 is a key regulator of anti-cancer immune responses induced by genotoxic stress and that its inhibition can switch cancer cell clearance from primarily apoptotic to immunogenic, promoting and maintaining durable anti-tumor immune responses. © 2021. The Author(s).

• Cancer Research
,
• Cardiovascular biology
,
• Stem Cells and Developmental Biology
,
• Mus musculus (House mouse)

In Developmental Cell on 11 October 2021 by Kim, J., Chuang, H. C., et al.

PubMed

Cancer patients often die from symptoms that manifest at a distance from any tumor. Mechanisms underlying these systemic physiological perturbations, called paraneoplastic syndromes, may benefit from investigation in non-mammalian systems. Using a non-metastatic Drosophila adult model, we find that malignant-tumor-produced cytokines drive widespread host activation of JAK-STAT signaling and cause premature lethality. STAT activity is particularly high in cells of the blood-brain barrier (BBB), where it induces aberrant BBB permeability. Remarkably, inhibiting STAT in the BBB not only rescues barrier function but also extends the lifespan of tumor-bearing hosts. We identify BBB damage in other pathological conditions that cause elevated inflammatory signaling, including obesity and infection, where BBB permeability also regulates host survival. IL-6-dependent BBB dysfunction is further seen in a mouse tumor model, and it again promotes host morbidity. Therefore, BBB alterations constitute a conserved lethal tumor-host interaction that also underlies other physiological morbidities. Copyright © 2021 Elsevier Inc. All rights reserved.

• Stem Cells and Developmental Biology

In Stem Cell Research & Therapy on 18 August 2021 by Forsberg, M. H., Kink, J. A., et al.

PubMed

Acute radiation syndrome (ARS) is caused by acute exposure to ionizing radiation that damages multiple organ systems but especially the bone marrow (BM). We have previously shown that human macrophages educated with exosomes from human BM-derived mesenchymal stromal cells (MSCs) primed with lipopolysaccharide (LPS) prolonged survival in a xenogeneic lethal ARS model. The purpose of this study was to determine if exosomes from LPS-primed MSCs could directly educate human monocytes (LPS-EEMos) for the treatment of ARS. Human monocytes were educated by exosomes from LPS-primed MSCs and compared to monocytes educated by unprimed MSCs (EEMos) and uneducated monocytes to assess survival and clinical improvement in a xenogeneic mouse model of ARS. Changes in surface molecule expression of exosomes and monocytes after education were determined by flow cytometry, while gene expression was determined by qPCR. Irradiated human CD34+ hematopoietic stem cells (HSCs) were co-cultured with LPS-EEMos, EEMos, or uneducated monocytes to assess effects on HSC survival and proliferation. LPS priming of MSCs led to the production of exosomes with increased expression of CD9, CD29, CD44, CD146, and MCSP. LPS-EEMos showed increases in gene expression of IL-6, IL-10, IL-15, IDO, and FGF-2 as compared to EEMos generated from unprimed MSCs. Generation of LPS-EEMos induced a lower percentage of CD14+ monocyte subsets that were CD16+, CD73+, CD86+, or CD206+ but a higher percentage of PD-L1+ cells. LPS-EEMos infused 4 h after lethal irradiation significantly prolonged survival, reducing clinical scores and weight loss as compared to controls. Complete blood counts from LPS-EEMo-treated mice showed enhanced hematopoietic recovery post-nadir. IL-6 receptor blockade completely abrogated the radioprotective survival benefit of LPS-EEMos in vivo in female NSG mice, but only loss of hematopoietic recovery was noted in male NSG mice. PD-1 blockade had no effect on survival. Furthermore, LPS-EEMos also showed benefits in vivo when administered 24 h, but not 48 h, after lethal irradiation. Co-culture of unprimed EEMos or LPS-EEMos with irradiated human CD34+ HSCs led to increased CD34+ proliferation and survival, suggesting hematopoietic recovery may be seen clinically. LPS-EEMos are a potential counter-measure for hematopoietic ARS, with a reduced biomanufacturing time that facilitates hematopoiesis. © 2021. The Author(s).

• Cardiovascular biology
,
• Immunology and Microbiology

Preprint on Research Square on 23 June 2021 by Shin, S. J., Kang, T. G., et al.

PubMed

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is often exacerbated upon coinfection, but the underlying immunological mechanisms remain unclear. Here, to elucidate these mechanisms, we used a Mtb and lymphocytic choriomeningitis virus coinfection model. Viral coinfection significantly suppressed Mtb-specific IFN-γ production, with elevated bacterial loads and hyperinflammation in the lungs. Type I IFN signaling blockade rescued the Mtb-specific IFN-γ response and ameliorated lung immunopathology. Single-cell sequencing, tissue immunofluorescence staining, and adoptive transfer experiments revealed that type I IFN signaling produced in response to viral infection inhibited CXCL9/10 production in myeloid cells, resulting in impaired pulmonary migration of Mtb-specific CD4 + T cells from lymph nodes. Thus, virus coinfection-induced type I IFN signaling prior to the pulmonary localization of Mtb-specific Th1 cells exacerbates TB immunopathogenesis by impeding the Mtb-specific Th1 cell influx. Our study highlights another novel negative role of viral coinfection and/or type I IFNs in delaying Mtb-specific Th1 responses in the lung.

• FC/FACS
,
• Homo sapiens (Human)
,
• Immunology and Microbiology
,
• Mus musculus (House mouse)

In Immunity on 8 June 2021 by Harb, H., Benamar, M., et al.

PubMed

A cardinal feature of COVID-19 is lung inflammation and respiratory failure. In a prospective multi-country cohort of COVID-19 patients, we found that increased Notch4 expression on circulating regulatory T (Treg) cells was associated with disease severity, predicted mortality, and declined upon recovery. Deletion of Notch4 in Treg cells or therapy with anti-Notch4 antibodies in conventional and humanized mice normalized the dysregulated innate immunity and rescued disease morbidity and mortality induced by a synthetic analog of viral RNA or by influenza H1N1 virus. Mechanistically, Notch4 suppressed the induction by interleukin-18 of amphiregulin, a cytokine necessary for tissue repair. Protection by Notch4 inhibition was recapitulated by therapy with Amphiregulin and, reciprocally, abrogated by its antagonism. Amphiregulin declined in COVID-19 subjects as a function of disease severity and Notch4 expression. Thus, Notch4 expression on Treg cells dynamically restrains amphiregulin-dependent tissue repair to promote severe lung inflammation, with therapeutic implications for COVID-19 and related infections. Copyright © 2021 Elsevier Inc. All rights reserved.

• Mus musculus (House mouse)
,
• Immunology and Microbiology
,
• Pharmacology

In Frontiers in Pharmacology on 20 October 2020 by Rubsamen, R., Burkholz, S., et al.

PubMed

Cytokine release syndrome (CRS) is known to be a factor in morbidity and mortality associated with acute viral infections including those caused by filoviruses and coronaviruses. IL-6 has been implicated as a cytokine negatively associated with survival after filovirus and coronavirus infection. However, IL-6 has also been shown to be an important mediator of innate immunity and important for the host response to an acute viral infection. Clinical studies are now being conducted by various researchers to evaluate the possible role of IL-6 blockers to improve outcomes in critically ill patients with CRS. Most of these studies involve the use of anti-IL-6R monoclonal antibodies (α-IL-6R mAbs). We present data showing that direct neutralization of IL-6 with an α-IL-6 mAb in a BALB/c Ebolavirus (EBOV) challenge model produced a statistically significant improvement in outcome compared with controls when administered within the first 24 h of challenge and repeated every 72 h. A similar effect was seen in mice treated with the same dose of α-IL-6R mAb when the treatment was delayed 48 h post-challenge. These data suggest that direct neutralization of IL-6, early during the course of infection, may provide additional clinical benefits to IL-6 receptor blockade alone during treatment of patients with virus-induced CRS. Copyright © 2020 Rubsamen, Burkholz, Massey, Brasel, Hodge, Wang, Herst, Carback and Harris.