Inflammation
Abstract
Endothelial dysfunction is a critical and initiating factor of the vascular complications of diabetes. Inflammation plays an important role in endothelial dysfunction regulated by epigenetic modifications. N6-methyladenosine (m6A) is one of the most prevalent epigenetic modifications in eukaryotic cells. In this research, we identified an m6A demethylase, fat mass and obesity-associated protein (FTO), as an essential epitranscriptomic regulator in diabetes-induced vascular endothelial dysfunction. We showed that enhanced FTO reduced the global level of m6A in hyperglycemia. FTO knockdown in endothelial cells (ECs) resulted in less inflammation and compromised ability of migration and tube formation. Compared with EC Ftofl/fl diabetic mice, EC-specific Fto-deficient (EC FtoΔ/Δ) diabetic mice displayed less retinal vascular leakage and acellular capillary formation. Furthermore, methylated RNA immunoprecipitation sequencing (MeRIP-Seq) combined with RNA-Seq indicated that Tnip1 served as a downstream target of FTO. Luciferase activity assays and RNA pull-down demonstrated that FTO repressed TNIP1 mRNA expression by erasing its m6A methylation. In addition, TNIP1 depletion activated NF-κB and other inflammatory factors, which aggravated retinal vascular leakage and acellular capillary formation, while sustained expression of Tnip1 by intravitreal injection of adeno-associated virus alleviated endothelial impairments. These findings suggest that the FTO-TNIP1-NF-κB network provides potential targets to treat diabetic vascular complications.
Authors
Chuandi Zhou, Xinping She, Chufeng Gu, Yanan Hu, Mingming Ma, Qinghua Qiu, Tao Sun, Xun Xu, Haibing Chen, Zhi Zheng
Abstract
Type 2 diabetes mellitus (T2DM), characterized by hyperglycemia and dyslipidemia, leads to nonproliferative diabetic retinopathy (NPDR). NPDR is associated with blood-retina barrier disruption, plasma exudates, microvascular degeneration, elevated inflammatory cytokine levels, and monocyte (Mo) infiltration. Whether and how the diabetes-associated changes in plasma lipid and carbohydrate levels modify Mo differentiation remains unknown. Here, we show that mononuclear phagocytes (MPs) in areas of vascular leakage in DR donor retinas expressed perilipin 2 (PLIN2), a marker of intracellular lipid load. Strong upregulation of PLIN2 was also observed when healthy donor Mos were treated with plasma from patients with T2DM or with palmitate concentrations typical of those found in T2DM plasma, but not under high-glucose conditions. PLIN2 expression correlated with the expression of other key genes involved in lipid metabolism (ACADVL, PDK4) and the DR biomarkers ANGPTL4 and CXCL8. Mechanistically, we show that lipid-exposed MPs induced capillary degeneration in ex vivo explants that was inhibited by pharmaceutical inhibition of PPARγ signaling. Our study reveals a mechanism linking dyslipidemia-induced MP polarization to the increased inflammatory cytokine levels and microvascular degeneration that characterize NPDR. This study provides comprehensive insights into the glycemia-independent activation of Mos in T2DM and identifies MP PPARγ as a target for inhibition of lipid-activated MPs in DR.
Authors
Guillaume Blot, Rémi Karadayi, Lauriane Przegralek, Thérèse-Marie Sartoris, Hugo Charles-Messance, Sébastien Augustin, Pierre Negrier, Frédéric Blond, Frida Paulina Muñiz-Ruvalcaba, David Rivera-de la Parra, Lucile Vignaud, Aude Couturier, José-Alain Sahel, Niyazi Acar, Aida Jimenez-Corona, Cécile Delarasse, Yonathan Garfias, Florian Sennlaub, Xavier Guillonneau
Abstract
BACKGROUND. Macrophage activation syndrome (MAS) is a life-threatening complication of Still’s disease (SD) characterized by overt immune cell activation and cytokine storm. We aimed to further understand the immunologic landscape of SD and MAS. METHOD. We profiled peripheral blood mononuclear cells (PBMC) from healthy controls and patients with SD with or without MAS using bulk RNA sequencing (RNA-seq) and single-cell RNA-seq (scRNA-seq). We validated and expanded the findings by mass cytometry, flow cytometry and in vitro studies. RESULTS. Bulk RNA-seq of PBMC from patients with SD-associated MAS revealed strong expression of genes associated with type I interferon (IFN-I) signaling and cell proliferation, in addition to the expected IFN-γ signal, compared to healthy controls and SD patients without MAS. scRNA-seq analysis of > 65,000 total PBMC confirmed IFN-I and IFN-γ signatures and localized the cell proliferation signature to cycling CD38+HLA-DR+ cells within CD4+ T cell, CD8+ T cell and NK cell populations. CD38+HLA-DR+ lymphocytes exhibited prominent IFN-g production, glycolysis, and mTOR signaling. Cell-cell interaction modeling suggested a network linking CD38+HLA-DR+ lymphocytes with monocytes through IFN-γ signaling. Notably, the expansion of CD38+HLA-DR+ lymphocytes in MAS was greater than in other systemic inflammatory conditions in children. In vitro stimulation of PBMC demonstrated that IFN-I and IL-15 – both elevated in MAS patients – synergistically augmented the generation of CD38+HLA-DR+ lymphocytes, while Janus kinase inhibition mitigated this response. CONCLUSION. MAS associated with SD is characterized by overproduction of IFN-I, which may act in synergy with IL-15 to generate CD38+HLA-DR+ cycling lymphocytes that produce IFN-γ.
Authors
Zhengping Huang, Kailey E. Brodeur, Liang Chen, Yan Du, Holly Wobma, Evan E. Hsu, Meng Liu, Joyce C. Chang, Margaret H. Chang, Janet Chou, Megan Day-Lewis, Fatma Dedeoglu, Olha Halyabar, James A. Lederer, Tianwang Li, Mindy S. Lo, Meiping Lu, Esra Meidan, Jane W. Newburger, Adrienne G. Randolph, Mary Beth F. Son, Robert P. Sundel, Maria L. Taylor, Huaxiang Wu, Qing Zhou, Scott W. Canna, Kevin Wei, Lauren A. Henderson, Peter A. Nigrovic, Pui Y. Lee
Abstract
Systemic autoimmune and autoinflammatory diseases are characterized by genetic and cellular heterogeneity. While current single-cell genomics methods provide insights into known disease subtypes, these analysis methods do not readily reveal novel cell-type perturbation programs shared amongst distinct patient subsets. Here, we performed single-cell RNA-Seq of PBMCs of systemic juvenile idiopathic arthritis (SJIA) patients with diverse clinical manifestations, including macrophage activation syndrome (MAS) and lung disease (LD). We introduced two new computational frameworks called UDON and SATAY-UDON which define new patient subtypes based on their underlying disrupted cellular programs as well as associated biomarkers or clinical features. Among twelve independently identified subtypes, this analysis uncovered a novel complement and interferon activation program identified in SJIA-LD monocytes. Extending these analyses to adult and pediatric lupus patients found new but also shared disease programs with SJIA, including interferon and complement activation. Finally, supervised comparison of these programs in a compiled single-cell pan-immune atlas of over 1,000 healthy donors found a handful of normal healthy donors with evidence of early inflammatory activation in subsets of monocytes and platelets, nominating new possible biomarkers for early disease detection. Thus, integrative pan-immune single-cell analysis resolved new conserved gene programs underlying inflammatory disease pathogenesis and associated complications.
Authors
Emely L. Verweyen, Kairavee Thakkar, Sanjeev Dhakal, Elizabeth J. Baker, Kashish Chetal, Daniel Schnell, Scott W. Canna, Alexei A. Grom, Nathan Salomonis, Grant S. Schulert
Abstract
Hormone replacement therapy (HRT) is not recommended for treating learning and memory decline in menopausal women because it exerts adverse effects by activating classic estrogen receptors ERα and ERβ. The membrane estrogen receptor G protein-coupled receptor 30 (GPR30) has been reported to be involved in memory modulation; however, the underlying mechanisms are poorly understood. Here, we found that GPR30 deletion in astrocytes, but not in neurons, impaired learning and memory in female mice. Astrocytic GPR30 depletion induced A1 phenotype transition, impairing neuronal function. Further exploration revealed that Praja1 (PJA1), a RING ubiquitin ligase, mediated the effects of astrocytic GPR30 on learning and memory by binding to Serpina3n, which is a molecular marker of neuroinflammation in astrocytes. GPR30 positively modulated PJA1 expression through the CREB signaling pathway in cultured murine and human astrocytes. Additionally, the mRNA levels of GPR30 and PJA1 were reduced in exosomes isolated from postmenopausal women while Serpina3n levels were increased in the plasma. Together, our findings suggest a key role for astrocytic GPR30 in the learning and memory abilities of female mice and identify GPR30/PJA1/Serpina3n as potential therapeutic targets for learning and memory loss in peri- and postmenopausal women.
Authors
Xinshang Wang, Yongli Jiang, Ban Feng, Xue Ma, Kun Zhang, Fan Yang, Zhenguo Liu, Le Yang, Jiao Yue, Liang Lu, Dake Song, Qingjuan Guo, Jingyu Qi, Xubo Li, Min Wang, Huinan Zhang, Jing Huang, Minggao Zhao, Shuibing Liu
Abstract
Multisystem inflammatory syndrome in children (MIS-C) is a rare but life-threatening hyperinflammatory condition induced by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes pediatric COVID-19 (pCOVID-19). The relationship of the systemic tissue injury to the pathophysiology of MIS-C is poorly defined. We leveraged the high sensitivity of epigenomic analyses of plasma cell-free DNA (cfDNA) and plasma cytokine measurements to identify the spectrum of tissue injury and glean mechanistic insights. Compared to pediatric healthy controls (pHC) and pCOVID-19, MIS-C patients had higher levels of cfDNA primarily derived from innate immune cells, megakaryocyte-erythroid precursor cells, and non-hematopoietic tissues such as hepatocytes, cardiac myocytes, and kidney cells. Non-hematopoietic tissue cfDNA levels demonstrated significant inter-individual variability, consistent with the heterogenous clinical presentation of MIS-C. In contrast, adaptive immune cell-derived cfDNA levels were comparable in MIS-C and pCOVID-19 patients. Indeed, the innate immune cells cfDNA in MIS-C correlated with levels of innate immune inflammatory cytokines and non-hematopoietic tissue-derived cfDNA, suggesting a primarily innate immunity-mediated response to account for multi-system pathology. These data provide insight into the pathogenesis of MIS-C and support the value of cfDNA as a sensitive biomarker to map tissue injury in MIS-C and likely other multi-organ inflammatory conditions.
Authors
Temesgen E. Andargie, Katerina Roznik, Neelam R. Redekar, Tom Hill, Weiqiang Zhou, Zainab Apalara, Hyesik Kong, Oren Gordon, Rohan Meda, Woojin Park, Trevor S. Johnston, Yi Wang, Sheila Brady, Hongkai Ji, Jack A. Yanovski, Moon Kyoo Jang, Clarence M. Lee, Andrew H. Karaba, Andrea L. Cox, Sean Agbor-Enoh
Abstract
The NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome is a crucial component of the innate immune system that initiates inflammatory responses. Post-translational modifications (PTMs) of NLRP3, including ubiquitination and phosphorylation, control inflammasome activation and determine the intensity of inflammation. However, the role of other PTMs in controlling NLRP3 inflammasome activation remains unclear. This study founded that toll-like receptor (TLR) priming induced NLRP3 ISGylation (a type of PTM in which ISG15 covalently binds to the target protein) to stabilise the NLRP3 protein. Viral infection, represented by SARS-COV-2 infection, and type I IFNs induced the expression of ISG15 and the predominant E3 ISGylation ligases HECT domain- and RCC1-like domain-containing proteins (HERCs; HERC5 in humans and HERC6 in mice). HERCs promoted NLRP3 ISGylation and inhibited K48-linked ubiquitination and proteasomal degradation, resulting in the enhancement of NLRP3 inflammasome activation. Concordantly, Herc6 deficiency ameliorated NLRP3-dependent inflammation, and hyperinflammation caused by viral infection. These results illustrate the mechanism by which type I IFNs responses control inflammasome activation and viral infection-induced aberrant NLRP3 activation. This work identifies ISGylation as a PTM of NLRP3 and provides a priming target for modulating NLRP3-dependent immunopathology.
Authors
Ying Qin, Xintong Meng, Mengge Wang, Wenbo Liang, Rong Xu, Jingchunyu Chen, Hui Song, Yue Fu, Jingxin Li, Chengjiang Gao, Mutian Jia, Chunyuan Zhao, Wei Zhao
Abstract
Disease-initiating mutations in the transcription factor RUNX1 occur as germline and somatic events that cause leukemias with particularly poor prognosis. However, the role of RUNX1 in leukemogenesis is not fully understood and effective therapies for RUNX1-mutant leukemias remain elusive. Here, we use primary patient samples and a RUNX1 knockout model in primary human hematopoietic cells to investigate how RUNX1 loss contributes to leukemic progression and to identify targetable vulnerabilities. Surprisingly, we found that RUNX1 loss decreased proliferative capacity and stem cell function. However, RUNX1-deficient cells selectively upregulated the interleukin-3 (IL-3) receptor. Exposure to IL-3, but not other JAK/STAT cytokines, rescued RUNX1 KO proliferative and competitive defects. Further, we demonstrated that RUNX1 loss repressed JAK/STAT signaling and rendered RUNX1-deficient cells sensitive to JAK inhibitors. Our study identifies a dependency of RUNX1-mutant leukemias on IL-3/JAK/STAT signaling, which may enable these aggressive blood cancers to be targeted with existing agents.
Authors
Amy C. Fan, Yusuke Nakauchi, Lawrence Bai, Armon Azizi, Kevin A. Nuno, Feifei Zhao, Thomas Köhnke, Daiki Karigane, David Cruz-Hernandez, Andreas Reinisch, Purvesh Khatri, Ravindra Majeti
Abstract
Glial activation and inflammation coincide with neurofibrillary tangles (NFT) formation in neurons. However, the mechanism behind tau fibril and glia interaction is poorly understood. Here, we found that tau preformed fibrils (PFF) caused induction of inflammation in microglia by specifically activating the TLR2-MyD88, but not TLR4-MyD88, pathway. Accordingly, TLR2 interacting domain of MyD88 (wtTIDM) peptide inhibited tau PFF-induced activation of TLR2-MyD88-NF-κB pathway resulting in reduced inflammation. Nasal administration of wtTIDM in P301S tau-expressing PS19 mice was found to inhibit gliosis and inflammatory markers, along with reduction of pathogenic tau in the hippocampus, resulting in improved cognitive behavior in PS19 mice. The inhibitory effect of wtTIDM on tau pathology was absent in PS19 mice lacking TLR2, reinforcing the essential involvement of TLR2 in wtTIDM- mediated effects in vivo. While understanding the mechanism further, we found that tau promoter harboured a potential NF-κB binding site and that proinflammatory molecules increased the transcription of tau in neurons via NF-κB. These results suggest that tau-induced neuroinflammation and neuropathology require TLR2 and that neuroinflammation directly upregulates tau in neurons via NF-κB, highlighting a direct connection between inflammation and tauopathy.
Authors
Debashis Dutta, Malabendu Jana, Ramesh Kumar Paidi, Moumita Majumder, Sumita Raha, Sridevi Dasarathy, Kalipada Pahan
Abstract
RATIONALE. Food allergy (FA) is a growing health problem requiring physiologic confirmation via the oral food challenge (OFC). Many OFCs result in clinical anaphylaxis, causing discomfort and risk while limiting OFC utility. Transepidermal water loss (TEWL) measurement provides a potential solution to detect food anaphylaxis in real time prior to clinical symptoms. We evaluated whether TEWL changes during an OFC could predict anaphylaxis onset. METHODS. Physicians and nurses blind to TEWL results conducted and adjudicated the results of all 209 OFCs in this study. A study coordinator measured TEWL throughout the OFC and had no input on OFC conduct. TEWL was measured two ways in two separate groups. First, TEWL was measured using static, discrete measurements. Second, TEWL was measured using continuous monitoring. Participants who consented gave blood before and after OFCs for biomarker analyses. RESULTS. TEWL rose significantly (2.93 g/m2/h) during reactions and did not rise during non-reacting OFCs (-1.00 g/m2/h). Systemic increases in tryptase and interleukin-3 were also detected during reactions, providing supporting biochemical evidence of anaphylaxis. The TEWL rise occurred 48 minutes earlier than clinically evident anaphylaxis. Continuous monitoring detected a significant rise in TEWL that presaged positive OFCs, but no rise was seen in OFCs with no reaction, providing high predictive specificity (96%) for anaphylaxis against non-reactions 38 minutes prior to anaphylaxis. CONCLUSIONS. During OFCs, a TEWL rise anticipates a positive clinical challenge. TEWL presents a novel monitoring modality that may predict food anaphylaxis and facilitate improvements in OFC safety and tolerability.
Authors
Charles F. Schuler, Kelly M. O'Shea, Jonathan P. Troost, Bridgette Kaul, Christopher M. Launius, Jayme Cannon, David M. Manthei, George E. Freigeh, Georgiana Sanders, Simon P. Hogan, Nicholas W. Lukacs, James R. Baker Jr
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Copyright © 2024 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)