BACKGROUND. Inflammation helps regulate normal growth and tissue repair. Although bone morphogenetic proteins (BMPs) and inflammation are known contributors to abnormal bone formation, how these pathways interact in ossification remains unclear. METHODS. We examined this potential link in patients with fibrodysplasia ossificans progressiva (FOP), a genetic condition of progressive heterotopic ossification caused by activating mutations in the Activin A type I receptor (ACVR1/ALK2). FOP patients show exquisite sensitivity to trauma, suggesting that BMP pathway activation may alter immune responses. We studied primary blood, monocyte, and macrophage samples from control and FOP subjects using multiplex cytokine, gene expression, and protein analyses; examined CD14+ primary monocyte and macrophage responses to TLR ligands; and assayed BMP, TGF-β activated kinase 1 (TAK1), and NF-κB pathways. RESULTS. FOP subjects at baseline without clinically evident heterotopic ossification showed increased serum IL-3, IL-7, IL-8, and IL-10. CD14+ primary monocytes treated with the TLR4 activator LPS showed increased CCL5, CCR7, and CXCL10; abnormal cytokine/chemokine secretion; and prolonged activation of the NF-κB pathway. FOP macrophages derived from primary monocytes also showed abnormal cytokine/chemokine secretion, increased TGF-β production, and p38MAPK activation. Surprisingly, SMAD phosphorylation was not significantly changed in the FOP monocytes/macrophages. CONCLUSIONS. Abnormal ACVR1 activity causes a proinflammatory state via increased NF-κB and p38MAPK activity. Similar changes may contribute to other types of heterotopic ossification, such as in scleroderma and dermatomyositis; after trauma; or with recombinant BMP-induced bone fusion. Our findings suggest that chronic antiinflammatory treatment may be useful for heterotopic ossification.
Emilie Barruet, Blanca M. Morales, Corey J. Cain, Amy N. Ton, Kelly L. Wentworth, Tea V. Chan, Tania A. Moody, Mariëlle C. Haks, Tom H.M. Ottenhoff, Judith Hellman, Mary C. Nakamura, Edward C. Hsiao
Asthma is one of the most common immunological diseases and is characterized by airway hyperresponsiveness (AHR), mucus overproduction, and airway eosinophilia. Although mouse models have provided insight into the mechanisms by which type-2 cytokines induce asthmatic airway inflammation, differences between the rodent and human immune systems hamper efforts to improve understanding of human allergic diseases. In this study, we aim to establish a preclinical animal model of asthmatic airway inflammation using humanized IL-3/GM-CSF or IL-3/GM-CSF/IL-5 Tg NOD/Shi-scid-IL2rγnull (NOG) mice and investigate the roles of human type-2 immune responses in the asthmatic mice. Several important characteristics of asthma — such as AHR, goblet cell hyperplasia, T cell infiltration, IL-13 production, and periostin secretion — were induced in IL-3/GM-CSF Tg mice by intratracheally administered human IL-33. In addition to these characteristics, human eosinophilic inflammation was observed in IL-3/GM-CSF/IL-5 Tg mice. The asthmatic mechanisms of the humanized mice were driven by activation of human Th2 and mast cells by IL-33 stimulation. Furthermore, treatment of the humanized mice with an anti–human IL-13 antibody significantly suppressed these characteristics. Therefore, the humanized mice may enhance our understanding of the pathophysiology of allergic disorders and facilitate the preclinical development of new therapeutics for IL-33–mediated type-2 inflammation in asthma.
Ryoji Ito, Shuichiro Maruoka, Kaori Soda, Ikumi Katano, Kenji Kawai, Mika Yagoto, Asami Hanazawa, Takeshi Takahashi, Tomoyuki Ogura, Motohito Goto, Riichi Takahashi, Shota Toyoshima, Yoshimichi Okayama, Kenji Izuhara, Yasuhiro Gon, Shu Hashimoto, Mamoru Ito, Satoshi Nunomura
In this study we evaluated the role of hyaluronan (HA) in reactive adipogenesis, a local expansion of preadipocytes that provides host defense by release of antimicrobial peptides. We observed that HA accumulated during maturation of adipocytes in vitro and was associated with increased expression of preadipocyte factor 1, zinc finger protein 423, and early B cell factor 1. Although HA is normally abundant in the extracellular matrix, a further increase in HA staining occurred in mice at sites of reactive adipogenesis following injury of colon by dextran sodium sulfate or injury of skin from infection with Staphylococcus aureus. HA also abundantly accumulated around adipocytes seen in the colons of patients with inflammatory bowel disease. This HA was necessary for adipocyte maturation because digestion of HA by administration of soluble hyaluronidase or transgenic expression of hyaluronidase 1 inhibited adipogenesis in vitro and in vivo. Furthermore, hyaluronidase also suppressed inflammation of both skin and colon and decreased antimicrobial peptide expression by developing preadipocytes. This resulted in increased bacterial transit across the epithelial barrier despite decreased tissue injury from inflammation. These observations suggest HA plays an important role in reactive adipogenesis and host defense after injury.
Tatsuya Dokoshi, Ling-juan Zhang, Teruaki Nakatsuji, Christopher A. Adase, James A. Sanford, Rudolph D. Paladini, Hiroki Tanaka, Mikihiro Fujiya, Richard L. Gallo
Aortic dissection (AD) is a life-threatening vascular disease with limited treatment strategies. Here, we show that loss of the GWAS-identified SH2B3 gene, encoding lymphocyte adaptor protein LNK, markedly increases susceptibility to acute AD and rupture in response to angiotensin (Ang) II infusion. As early as day 3 following Ang II infusion, prior to the development of AD, Lnk–/– aortas display altered mechanical properties, increased elastin breaks, collagen thinning, enhanced neutrophil accumulation, and increased MMP-9 activity compared with WT mice. Adoptive transfer of Lnk–/– leukocytes into Rag1–/– mice induces AD and rupture in response to Ang II, demonstrating that LNK deficiency in hematopoietic cells plays a key role in this disease. Interestingly, treatment with doxycycline prevents the early accumulation of aortic neutrophils and significantly reduces the incidence of AD and rupture. PrediXcan analysis in a biobank of more than 23,000 individuals reveals that decreased expression of SH2B3 is significantly associated with increased frequency of AD-related phenotypes (odds ratio 0.81). Thus, we identified a role for LNK in the pathology of AD in experimental animals and humans and describe a new model that can be used to inform both inherited and acquired forms of this disease.
Fanny Laroumanie, Arina Korneva, Matthew R. Bersi, Matthew R. Alexander, Liang Xiao, Xue Zhong, Justin P. Van Beusecum, Yuhan Chen, Mohamed A. Saleh, William G. McMaster, Kyle A. Gavulic, Bethany L. Dale, Shilin Zhao, Yan Guo, Yu Shyr, Daniel S. Perrien, Nancy J. Cox, John A. Curci, Jay D. Humphrey, Meena S. Madhur
Molecular mechanisms that control leukocyte migration across the vascular endothelium (transendothelial migration; TEndoM) have been extensively characterized in vivo, but details of leukocyte transepithelial migration (TEpM) and its dysregulation (a pathologic feature of many mucosal diseases) are missing due to the lack of suitable animal models. Here, we describe a murine model that utilizes a vascularized proximal colonic segment (pcLoop) and enables quantitative studies of leukocyte trafficking across colonic epithelium. Consistent with previous in vitro studies, intraluminal injection of antibodies against integrin CD11b/CD18 reduced recruitment of polymorphonuclear neutrophils (PMN) into the lumen of pcLoops, and it increased subepithelial accumulation of PMN. We extended studies using the pcLoop to determine contributions of Junctional Adhesion Molecule-A (JAM-A, or F11R) in PMN TEpM and confirmed that mice with total loss of JAM-A or mice with intestinal epithelial selective loss of JAM-A had increased colonic permeability. Furthermore, there was reduced PMN migration into the colonic lumen that paralleled subepithelial accumulation of PMN in global-KO mice, as well as in intestinal epithelial-targeted JAM-A–deficient mice. These findings highlight a potentially novel role for JAM-A in regulating PMN TEpM in vivo and demonstrate utility of this model for identifying receptors that may be targeted in vivo to reduce pathologic intestinal inflammation.
Sven Flemming, Anny-Claude Luissint, Asma Nusrat, Charles A. Parkos
BACKGROUND. Lymphedema is a common condition affecting millions around the world that still lacks approved medical therapy. Because ketoprofen, an NSAID, has been therapeutic in experimental lymphedema, we evaluated its efficacy in humans. METHODS. We first performed an exploratory open-label trial. Patients with either primary or secondary lymphedema received ketoprofen 75 mg by mouth 3 times daily for 4 months. Subjects were evaluated for changes in histopathology, with skin thickness, limb volume, and tissue bioimpedance changes serving as secondary endpoints. Based on our encouraging findings, we next conducted a placebo-controlled trial, with the primary outcome defined as a change in skin thickness, as measured by skin calipers. Secondary endpoints for this second study included histopathology, limb volume, bioimpedance, and systemic inflammatory mediators. RESULTS. We enrolled 21 lymphedema patients in the open-label trial, from November 2010 to July 2011. Histopathology and skin thickness were significantly improved at 4 months compared with baseline. In the follow-up, double-blind, placebo-controlled trial, we enrolled 34 patients from August 2011 to October 2015, with 16 ketoprofen recipients and 18 placebo-treated subjects. No serious adverse events occurred. The ketoprofen recipients demonstrated reduced skin thickness, as well as improved composite measures of histopathology and decreased plasma granulocyte CSF (G-CSF) expression. CONCLUSION. These 2 exploratory studies together support the utility of targeted antiinflammatory therapy with ketoprofen in patients with lymphedema. Our results highlight the promise of such approaches to help restore a failing lymphatic circulation. TRIAL REGISTRATION. ClinicalTrials.gov NCT02257970.
Stanley G. Rockson, Wen Tian, Xinguo Jiang, Tatiana Kuznetsova, Francois Haddad, Jamie Zampell, Babak Mehrara, Joshua P. Sampson, Leslie Roche, Jinah Kim, Mark R. Nicolls
Neuroinflammation is a recognized pathogenic mechanism underlying motor neuron degeneration in amyotrophic lateral sclerosis (ALS), but the inflammatory mechanisms influencing peripheral motor axon degeneration remain largely unknown. A recent report showed a pathogenic role for c-Kit–expressing mast cells mediating inflammation and neuromuscular junction denervation in muscles from SOD1G93A rats. Here, we have explored whether mast cells infiltrate skeletal muscles in autopsied muscles from ALS patients. We report that degranulating mast cells were abundant in the quadriceps muscles from ALS subjects but not in controls. Mast cells were associated with myofibers and motor endplates and, remarkably, interacted with neutrophils forming large extracellular traps. Mast cells and neutrophils were also abundant around motor axons in the extensor digitorum longus muscle, sciatic nerve, and ventral roots of symptomatic SOD1G93A rats, indicating that immune cell infiltration extends along the entire peripheral motor pathway. Postparalysis treatment of SOD1G93A rats with the tyrosine kinase inhibitor drug masitinib prevented mast cell and neutrophil infiltration, axonal pathology, secondary demyelination, and the loss of type 2B myofibers, compared with vehicle-treated rats. These findings provide further evidence for a yet unrecognized contribution of immune cells in peripheral motor pathway degeneration that can be therapeutically targeted by tyrosine kinase inhibitors.
Emiliano Trias, Peter H. King, Ying Si, Yuri Kwon, Valentina Varela, Sofía Ibarburu, Mariángeles Kovacs, Ivan C. Moura, Joseph S. Beckman, Olivier Hermine, Luis Barbeito
Maternal obesity and a high-fat diet (HFD) during the perinatal period have documented short- and long-term adverse outcomes for offspring. However, the mechanisms of maternal HFD effects on neonatal offspring are unclear. While the effects of maternal HFD exposure during pregnancy on the offspring are increasingly being appreciated, we do not know if maternal HFD alters the microbiota or affects neonatal susceptibility to inflammatory conditions, nor the mechanisms involved. In this study, we show that the offspring of mothers exposed to HFD develop a unique microbiota, marked by expansion of Firmicutes, and an increase in IL-17–producing type 3 innate lymphoid cells (ILC3s). The expansion of ILC3s was recapitulated through neocolonization with HFD microbiota alone. Further, the HFD offspring were susceptible to a neonatal model of inflammation that was reversible with IL-17 blockade. Collectively, these data suggest a previously unknown and unique role for ILC3s in the promotion of an early inflammatory susceptibility in the offspring of mothers exposed to HFD.
Sarah Thomas Babu, Xinying Niu, Megan Raetz, Rashmin C. Savani, Lora V. Hooper, Julie Mirpuri
The acute respiratory distress syndrome (ARDS) causes an estimated 70,000 US deaths annually. Multiple pharmacologic interventions for ARDS have been tested and failed. An unmet need is a suitable laboratory human model to predictively assess emerging therapeutics on organ function in ARDS. We previously demonstrated that the small molecule BC1215 blocks actions of a proinflammatory E3 ligase–associated protein, FBXO3, to suppress NF-κB signaling in animal models of lung injury. Ex vivo lung perfusion (EVLP) is a clinical technique that maintains lung function for possible transplant after organ donation. We used human lungs unacceptable for transplant to model endotoxemic injury with EVLP for 6 hours. LPS infusion induced inflammatory injury with impaired oxygenation of pulmonary venous circulation. BC1215 treatment after LPS rescued oxygenation and decreased inflammatory cytokines in bronchoalveolar lavage. RNA sequencing transcriptomics from biopsies taken during EVLP revealed robust inflammatory gene induction by LPS with a strong signal for NF-κB–associated transcripts. BC1215 treatment reduced the LPS induction of genes associated with inflammatory and host defense gene responses by Gene Ontology (GOterm) and pathways analysis. BC1215 also significantly antagonized LPS-mediated NF-κB activity. EVLP may provide a unique human platform for preclinical study of chemical entities such as FBXO3 inhibitors on tissue physiology.
Nathaniel M. Weathington, Diana Álvarez, John Sembrat, Josiah Radder, Nayra Cárdenes, Kentaro Noda, Qiaoke Gong, Hesper Wong, Jay Kolls, Jonathan D’Cunha, Rama K. Mallampalli, Bill B. Chen, Mauricio Rojas
Macrophages polarize into heterogeneous proinflammatory M1 and antiinflammatory M2 subtypes. Heme oxygenase 1 (HO-1) protects against inflammatory processes such as ischemia-reperfusion injury (IRI), organ transplantation, and atherosclerosis. To test our hypothesis that HO-1 regulates macrophage polarization and protects against IRI, we generated myeloid-specific HO-1–knockout (mHO-1–KO) and –transgenic (mHO-1–Tg) mice, with deletion or overexpression of HO-1, in various macrophage populations. Bone marrow–derived macrophages (BMDMs) from mHO-1–KO mice, treated with M1-inducing LPS or M2-inducing IL-4, exhibited increased mRNA expression of M1 (CXCL10, IL-1β, MCP1) and decreased expression of M2 (Arg1 and CD163) markers as compared with controls, while BMDMs from mHO-1–Tg mice displayed the opposite. A similar pattern was observed in the hepatic M1/M2 expression profile in a mouse model of liver IRI. mHO-1–KO mice displayed increased hepatocellular damage, serum AST/ALT levels, Suzuki’s histological score of liver IRI, and neutrophil and macrophage infiltration, while mHO-1–Tg mice exhibited the opposite. In human liver transplant biopsies, subjects with higher HO-1 levels showed lower expression of M1 markers together with decreased hepatocellular damage and improved outcomes. In conclusion, myeloid HO-1 expression modulates macrophage polarization, and protects against liver IRI, at least in part by favoring an M2 phenotype.
Min Zhang, Kojiro Nakamura, Shoichi Kageyama, Akeem O. Lawal, Ke Wei Gong, May Bhetraratana, Takehiro Fujii, Dawoud Sulaiman, Hirofumi Hirao, Subhashini Bolisetty, Jerzy W. Kupiec-Weglinski, Jesus A. Araujo
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