Inflammation
Abstract
The brain ventricles are part of the fluid compartments bridging the CNS with the periphery. Using MRI, we previously observed a pronounced increase in ventricle volume (VV) in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS). Here, we examined VV changes in EAE and MS patients in longitudinal studies with frequent serial MRI scans. EAE mice underwent serial MRI for up to 2 months, with gadolinium contrast as a proxy of inflammation, confirmed by histopathology. We performed a time-series analysis of clinical and MRI data from a prior clinical trial in which RRMS patients underwent monthly MRI scans over 1 year. VV increased dramatically during preonset EAE, resolving upon clinical remission. VV changes coincided with blood-brain barrier disruption and inflammation. VV was normal at the termination of the experiment, when mice were still symptomatic. The majority of relapsing-remitting MS (RRMS) patients showed dynamic VV fluctuations. Patients with contracting VV had lower disease severity and a shorter duration. These changes demonstrate that VV does not necessarily expand irreversibly in MS but, over short time scales, can expand and contract. Frequent monitoring of VV in patients will be essential to disentangle the disease-related processes driving short-term VV oscillations from persistent expansion resulting from atrophy.
Authors
Jason M. Millward, Paula Ramos Delgado, Alina Smorodchenko, Laura Boehmert, Joao Periquito, Henning M. Reimann, Christian Prinz, Antje Els, Michael Scheel, Judith Bellmann-Strobl, Helmar Waiczies, Jens Wuerfel, Carmen Infante-Duarte, Andreas Pohlmann, Frauke Zipp, Friedemann Paul, Thoralf Niendorf, Sonia Waiczies
Abstract
Background: Psoriasis is a chronic inflammatory skin disease with increased obesity, non-calcified coronary artery burden (NCB), and incident myocardial infarction. We sought to assess the relationship between inflammation, visceral adipose tissue (VAT), and NCB. Furthermore, we evaluated whether improvement in VAT would be associated with reduction in NCB over time in psoriasis. Methods: Consecutive psoriasis patients (PSO) underwent coronary computed-tomography angiography to quantify NCB and abdominal computed tomography to calculate VAT, at baseline (n=237), one year (n=176), and four-years (n=50). Results: Patients with high hs-CRP had significantly greater visceral adiposity (17952.9±849.2 vs 13370.7±806.8 cc3, p<0.001) and non-calcified coronary burden (1.26±0.03 vs 1.07±0.02 mm2) than those with low hs-CRP. Those with higher VAT had more systemic inflammation [hs-CRP: 2.5 (1.0-5.3) vs 1.2 (0.6-2.9) mg/L] with ~50% higher NCB (1.42±0.6 vs 0.91±0.2 mm2 , p<0.001). VAT associated with NCB in fully adjusted models (β=0.47, p<0.001). At one-year follow up, patients who had worsening hs-CRP had an increase in VAT (14748.7±878.1 to 15158.7±881.5 cc3; p=0.03), whereas those who improved hs-CRP improved their VAT (16876.1±915.2 to 16310.4±889.6 cc3; p=0.04). At one-year, in those who decreased VAT, there was 10.3% reduction in NCB (β=0.26, p<0.0001), which persisted in a subset at four-years (β=0.39, p=0.003). Conclusions: Inflammation drives development of VAT, increased cardiometabolic risk, and NCB in psoriasis. Reduction of inflammation associated with reduction in VAT, and associated with longitudinal improvement in NCB. These findings demonstrate the important role of inflammation in the development of VAT in humans and its impact on early atherogenesis.
Authors
Aparna Sajja, Khaled M. Abdelrahman, Aarthi S. Reddy, Amit K. Dey, Domingo E. Uceda, Sundus S. Lateef, Alexander V. Sorokin, Heather L. Teague, Jonathan H. Chung, Joshua P. Rivers, Aditya A. Joshi, Youssef A. Elnabawi, Aditya Goyal, Justin Rodante, Andrew Keel, Julie A. Erb-Alvarez, Benjamin Lockshin, Ronald Prussick, Evan L. Siegel, Martin P. Playford, Marcus Y. Chen, David A. Bluemke, Joel M. Gelfand, Nehal N. Mehta
Abstract
Peptidylarginine deiminases (PADs) are a family of calcium-dependent enzymes that are involved in a variety of human disorders, including cancer and autoimmune diseases. Although targeting PAD4 has shown no benefit in sepsis, the role of PAD2 remains unknown. Here, we report that PAD2 is engaged in sepsis and sepsis-induced acute lung injury in both human patients and mice. Pad2–/– or selective inhibition of PAD2 by a small molecule inhibitor increased survival and improved overall outcomes in mouse models of sepsis. Pad2 deficiency decreased neutrophil extracellular trap (NET) formation. Importantly, Pad2 deficiency inhibited Caspase-11–dependent pyroptosis in vivo and in vitro. Suppression of PAD2 expression reduced inflammation and increased macrophage bactericidal activity. In contrast to Pad2–/–, Pad4 deficiency enhanced activation of Caspase-11–dependent pyroptosis in BM-derived macrophages and displayed no survival improvement in a mouse sepsis model. Collectively, our findings highlight the potential of PAD2 as an indicative marker and therapeutic target for sepsis.
Authors
Yuzi Tian, Shibin Qu, Hasan B. Alam, Aaron M. Williams, Zhenyu Wu, Qiufang Deng, Baihong Pan, Jing Zhou, Baoling Liu, Xiuzhen Duan, Jianjie Ma, Santanu Mondal, Paul R. Thompson, Kathleen A. Stringer, Theodore J. Standiford, Yongqing Li
Abstract
Loss-of-function variants of protein tyrosine phosphatase non-receptor type 2 (PTPN2) enhance risk of inflammatory bowel disease and rheumatoid arthritis; however, whether the association between PTPN2 and autoimmune arthritis depends on gut inflammation is unknown. Here we demonstrate that induction of subclinical intestinal inflammation exacerbates development of autoimmune arthritis in SKG mice. Ptpn2-haploinsufficient SKG mice — modeling human carriers of disease-associated variants of PTPN2 — displayed enhanced colitis-induced arthritis and joint accumulation of Tregs expressing RAR-related orphan receptor γT (RORγt) — a gut-enriched Treg subset that can undergo conversion into FoxP3–IL-17+ arthritogenic exTregs. SKG colonic Tregs underwent higher conversion into arthritogenic exTregs when compared with peripheral Tregs, which was exacerbated by haploinsufficiency of Ptpn2. Ptpn2 haploinsufficiency led to selective joint accumulation of RORγt-expressing Tregs expressing the colonic marker G protein–coupled receptor 15 (GPR15) in arthritic mice and selectively enhanced conversion of GPR15+ Tregs into exTregs in vitro and in vivo. Inducible Treg-specific haploinsufficiency of Ptpn2 enhanced colitis-induced SKG arthritis and led to specific joint accumulation of GPR15+ exTregs. Our data validate the SKG model for studies at the interface between intestinal and joint inflammation and suggest that arthritogenic variants of PTPN2 amplify the link between gut inflammation and arthritis through conversion of colonic Tregs into exTregs.
Authors
Wan-Chen Hsieh, Mattias N.D. Svensson, Martina Zoccheddu, Michael L. Tremblay, Shimon Sakaguchi, Stephanie M. Stanford, Nunzio Bottini
Abstract
The ability of HDL to inhibit inflammation in adipocytes and adipose tissue is reduced when HDL contains serum amyloid A (SAA) due to trapping of SAA in HDL by proteoglycans at the adipocyte surface. Since we recently found that the major extracellular matrix proteoglycan produced by hypertrophic adipocytes is versican, whereas activated adipose tissue macrophages produce mainly biglycan, the role of proteoglycans in determining the anti-inflammatory properties of HDL was further investigated. The distribution of versican, biglycan, apolipoprotein A-I (the major apolipoprotein of HDL) and SAA were similar in adipose tissue from obese mice and obese human subjects. Co-localization of SAA-enriched HDL with versican and biglycan at the cell surface of adipocyte and peritoneal macrophages, respectively, was blocked by silencing these proteoglycans, which also restored the anti-inflammatory property of SAA-enriched HDL despite the presence of SAA. Similar to adipocytes, normal HDL exerts its anti-inflammatory function in macrophages by reducing lipid rafts, reactive oxygen species generation and translocation of toll like receptor 4 and NADPH oxidase 2 into lipid rafts, effects that are not observed with SAA-enriched HDL. These findings imply that SAA present in HDL can be trapped by adipocyte-derived versican and macrophage-derived biglycan, thereby blunting HDL’s anti-inflammatory properties.
Authors
Chang Yeop Han, Inkyung Kang, Mohamed Omer, Shari Wang, Tomasz Wietecha, Thomas N. Wight, Alan Chait
Abstract
Hidradenitis Suppurativa (HS) is a chronic skin disorder of unknown etiology that manifests as recurrent, painful lesions. Cutaneous dysbiosis and unresolved inflammation are hallmarks of active HS, but their origin and interplay remain unclear. Our metabolomic profiling of HS skin revealed an abnormal induction of the kynurenine pathway (KP) of tryptophan catabolism in dermal fibroblasts correlating with the release of KP-inducing cytokines by inflammatory cell infiltrates. Notably, over-activation of the KP in lesional skin was associated with local and systemic depletion in tryptophan. Yet the skin microbiota normally degrades host tryptophan into indoles regulating tissue inflammation via engagement of the Aryl Hydrocarbon Receptor (AHR). In HS skin lesions, we detected contextual defects in AHR activation coinciding with impaired production of bacteria-derived AHR agonists and decreased incidence of AHR ligand-producing bacteria in the resident flora. Dysregulation of tryptophan catabolism at the skin-microbiota interface thus provides a mechanism linking the immunological and microbiological features of HS lesions. In addition to revealing metabolic alterations in HS patients, our study suggests that correcting AHR signaling would help restore immune homeostasis in HS skin.
Authors
Laure Guenin-Macé, Jean-David Morel, Jean-Marc Doisne, Angèle Schiavo, Lysiane Boulet, Véronique Mayau, Pedro Goncalves, Sabine Duchatelet, Alain Hovnanian, Vincent Bondet, Darragh Duffy, Marie-Noëlle Ungeheuer, Maïa Delage, Aude Nassif, James P. Di Santo, Caroline Demangel
Abstract
We determined that renal proximal tubular (PT) NFκB essential modulator (NEMO) plays a direct and critical role in ischemic acute kidney injury (AKI) utilizing using mice lacking renal PT NEMO and by targeted renal PT NEMO inhibition with mesoscale nanoparticle encapsulated NEMO binding peptide (MNP NBP). We subjected renal PT NEMO deficient mice, wild type (WT) mice and C57BL/6 mice to sham surgery or 30 min renal ischemia and reperfusion (IR). C57BL/6 mice received NBP MNP or empty MNP before renal IR injury. Mice treated with MNP NBP and mice deficient in renal PT NEMO were protected against ischemic AKI with decreased renal tubular necrosis, inflammation and apoptosis compared to control MNP treated or WT mice, respectively. Recombinant peptidylarginine deiminase type-4 (rPAD4) targets kidney PT NEMO to exacerbate ischemic AKI as exogenous rPAD4 exacerbated renal IR injury in WT mice but not in renal proximal tubule NEMO deficient mice. Furthermore, rPAD4 upregulated proinflammatory cytokine mRNA and NFκB activation in freshly isolated renal proximal tubules from WT mice but not from PT NEMO deficient mice. Taken together, our studies suggest that renal PT NEMO plays a critical role in ischemic AKI by promoting renal tubular inflammation, apoptosis as well as necrosis.
Authors
Sang Jun Han, Ryan M. williams, Mihwa Kim, Daniel A. Heller, Vivette D'Agati, Marc Schmidt-Supprian, H. Thomas Lee
Abstract
Macrophages are a primary immune cell involved in inflammation, and their cell plasticity allows for transition from an inflammatory to a reparative phenotype and is critical for normal tissue repair following injury. Evidence suggests that epigenetic alterations play a critical role in establishing macrophage phenotype and function during normal and pathologic wound repair. Here, we find in human and murine wound macrophages that cyclooxygenase 2/prostaglandin E2 (COX-2/PGE2) is elevated in diabetes and regulates downstream macrophage-mediated inflammation and host defense. Using single-cell RNA sequencing of human wound tissue, we identify increased NF-κB–mediated inflammation in diabetic wounds and show increased COX-2/PGE2 in diabetic macrophages. Further, we identify that COX-2/PGE2 production in wound macrophages requires epigenetic regulation of 2 key enzymes in the cytosolic phospholipase A2/COX-2/PGE2 (cPLA2/COX-2/PGE2) pathway. We demonstrate that TGF-β–induced miRNA29b increases COX-2/PGE2 production via inhibition of DNA methyltransferase 3b–mediated hypermethylation of the Cox-2 promoter. Further, we find mixed-lineage leukemia 1 (MLL1) upregulates cPLA2 expression and drives COX-2/PGE2. Inhibition of the COX-2/PGE2 pathway genetically (Cox2fl/fl Lyz2Cre+) or with a macrophage-specific nanotherapy targeting COX-2 in tissue macrophages reverses the inflammatory macrophage phenotype and improves diabetic tissue repair. Our results indicate the epigenetically regulated PGE2 pathway controls wound macrophage function, and cell-targeted manipulation of this pathway is feasible to improve diabetic wound repair.
Authors
Frank M. Davis, Lam C. Tsoi, Rachael Wasikowski, Aaron denDekker, Amrita Joshi, Carol Wilke, Hongping Deng, Sonya Wolf, Andrea Obi, Steven Huang, Allison C. Billi, Scott Robinson, Jay Lipinski, William J. Melvin, Christopher O. Audu, Stephan Weidinger, Steven L. Kunkel, Andrew Smith, Johann E. Gudjonsson, Bethany B. Moore, Katherine A. Gallagher
Abstract
Type 1 diabetes (T1D) is a consequence of autoimmune β cell destruction, but the role of lipids in this process is unknown. We previously reported that activation of Ca2+-independent phospholipase A2β (iPLA2β) modulates polarization of macrophages (MΦ). Hydrolysis of the sn-2 substituent of glycerophospholipids by iPLA2β can lead to the generation of oxidized lipids (eicosanoids), pro- and antiinflammatory, which can initiate and amplify immune responses triggering β cell death. As MΦ are early triggers of immune responses in islets, we examined the impact of iPLA2β-derived lipids (iDLs) in spontaneous-T1D prone nonobese diabetic mice (NOD), in the context of MΦ production and plasma abundances of eicosanoids and sphingolipids. We find that (a) MΦNOD exhibit a proinflammatory lipid landscape during the prediabetic phase; (b) early inhibition or genetic reduction of iPLA2β reduces production of select proinflammatory lipids, promotes antiinflammatory MΦ phenotype, and reduces T1D incidence; (c) such lipid changes are reflected in NOD plasma during the prediabetic phase and at T1D onset; and (d) importantly, similar lipid signatures are evidenced in plasma of human subjects at high risk for developing T1D. These findings suggest that iDLs contribute to T1D onset and identify select lipids that could be targeted for therapeutics and, in conjunction with autoantibodies, serve as early biomarkers of pre-T1D.
Authors
Alexander J. Nelson, Daniel J. Stephenson, Robert N. Bone, Christopher L. Cardona, Margaret A. Park, Ying G. Tusing, Xiaoyong Lei, George Kokotos, Christina L. Graves, Clayton E. Mathews, Joanna Kramer, Martin J. Hessner, Charles E. Chalfant, Sasanka Ramanadham
Abstract
Airway mucociliary clearance (MCC) is the main mechanism of lung defense keeping airways free of infection and mucus obstruction. Airway surface liquid volume, ciliary beating, and mucus are central for proper MCC and critically regulated by sodium absorption and anion secretion. Impaired MCC is a key feature of muco-obstructive diseases. The calcium-activated potassium channel KCa.3.1, encoded by Kcnn4, participates in ion secretion, and studies showed that its activation increases Na+ absorption in airway epithelia, suggesting that KCa3.1-induced hyperpolarization was sufficient to drive Na+ absorption. However, its role in airway epithelium is not fully understood. We aimed to elucidate the role of KCa3.1 in MCC using a genetically engineered mouse. KCa3.1 inhibition reduced Na+ absorption in mouse and human airway epithelium. Furthermore, the genetic deletion of Kcnn4 enhanced cilia beating frequency and MCC ex vivo and in vivo. Kcnn4 silencing in the Scnn1b-transgenic mouse (Scnn1btg/+), a model of muco-obstructive lung disease triggered by increased epithelial Na+ absorption, improved MCC, reduced Na+ absorption, and did not change the amount of mucus but did reduce mucus adhesion, neutrophil infiltration, and emphysema. Our data support that KCa3.1 inhibition attenuated muco-obstructive disease in the Scnn1btg/+ mice. K+ channel modulation may be a therapeutic strategy to treat muco-obstructive lung diseases.
Authors
Génesis Vega, Anita Guequén, Amber R. Philp, Ambra Gianotti, Llilian Arzola, Manuel Villalón, Olga Zegarra-Moran, Luis J.V. Galietta, Marcus A. Mall, Carlos A. Flores
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