Inflammation
Abstract
Authors
Siqi Ming, Xingyu Li, Jingxian Shu, Xi Huang, Yongjian Wu
Abstract
Mammalian injury responses are predominantly characterized by fibrosis and scarring rather than functional regeneration. This limited regenerative capacity in mammals could reflect a loss of pro-regeneration programs or active suppression by genes functioning akin to tumor suppressors. To uncover programs governing regeneration in mammals, we screened transcripts in human subjects following laser rejuvenation treatment and compared them to mice with enhanced Wound Induced Hair Neogenesis (WIHN), a rare example of mammalian organogenesis. We found that Rnasel-/- mice exhibit an increased regenerative capacity, with elevated WIHN through enhanced IL-36α. Consistent with RNase L’s known role to stimulate caspase-1, we found that pharmacologic inhibition of caspases promoted regeneration in an IL-36 dependent manner in multiple epithelial tissues. We identified a negative feedback loop, where RNase L activated caspase-1 restrains the pro-regenerative dsRNA-TLR3 signaling cascade through the cleavage of toll-like adaptor protein TRIF. Through integrated single-cell RNA sequencing and spatial transcriptomic profiling, we confirmed Oas & Il36 genes to be highly expressed at the site of wounding and are elevated in Rnasel-/- mice wounds. This work suggests that RNase L functions as a regeneration repressor gene, in a functional tradeoff that tempers immune hyper-activation during viral infection at the cost of inhibiting regeneration.
Authors
Charles S. Kirby, Nasif Islam, Eric Wier, Martin P. Alphonse, Evan Sweren, Gaofeng Wang, Haiyun Liu, Dongwon Kim, Ang Li, Sam S. Lee, Andrew M. Overmiller, Yingchao Xue, Sashank Reddy, Nathan K. Archer, Lloyd S. Miller, Jianshi Yu, Weiliang Huang, Jace W. Jones, Sooah Kim, Maureen A. Kane, Robert H. Silverman, Luis A. Garza
Abstract
Preclinical and clinical observations indicate that the probiotic Lactobacillus rhamnosus GG (LGG) can modulate colonic inflammation. However, the underlying mechanisms have not been explored in depth. Here, we demonstrate that oral administration of live LGG alleviated inflammatory colitis by increasing IL-10 expression in intestinal Ly6C+ monocytes. Mechanistically, LGG induced IL-10 production via the stimulator of IFN genes (STING)/TBK1/NF-κB (RELA) signaling pathway in intestinal Ly6C+ monocytes, enhancing their immune-suppressive function. Elevated IL-10 subsequently activated IL-10 signaling in Ly6C+ monocytes, resulting in an IL-10–based autocrine regulatory loop and inhibition of proinflammatory cytokine production. Furthermore, LGG shifted the gut microbial community and its metabolic functions, leading to intestinal immune responses against colitis. Fecal microbiota transplantation from LGG-colonized mice alleviated immune checkpoint blockade–associated colitis. Our findings highlight the importance of STING signaling in IL-10–dependent antiinflammatory immunity and establish an empirical basis for developing oral administration of live LGG as an efficient and safe therapeutic strategy against inflammatory colitis.
Authors
Wei Si, Xin Zhao, Ruitong Li, Yaopeng Li, Cui Ma, Xiaohan Zhao, Jason Bugno, Yuchang Qin, Junmin Zhang, Hongwei Liu, Liangliang Wang
Abstract
Hypoxia is a major cause of pulmonary hypertension (PH) worldwide, and it is likely that interstitial pulmonary macrophages contribute to this vascular pathology. We observed in hypoxia-exposed mice an increase in resident interstitial macrophages, which expanded through proliferation and expressed the monocyte recruitment ligand CCL2. We also observed an increase in CCR2+ macrophages through recruitment, which express the protein thrombospondin-1 that functionally activates TGF-beta to cause vascular disease. Blockade of monocyte recruitment with either CCL2 neutralizing antibody treatment or CCR2 deficiency in the bone marrow compartment suppressed hypoxic PH. These data were supported by analysis of plasma samples from humans who travelled from low (225m) to high (3500m) elevation, revealing an increase in thrombospondin-1 and TGF-beta expression following ascent, which was blocked by dexamethasone prophylaxis. In the hypoxic mouse model, dexamethasone prophylaxis recapitulated these findings by mechanistically suppressing CCL2 expression and CCR2+ monocyte recruitment. These data suggest a pathologic cross-talk between two discrete interstitial macrophage populations, which can be therapeutically targeted.
Authors
Rahul Kumar, Kevin Nolan, Biruk Kassa, Neha Chanana, Tsering Palmo, Kavita Sharma, Kanika Singh, Claudia Mickael, Dara Fonseca Balladares, Julia Nilsson, Amit Prabhakar, Aastha Mishra, Michael H. Lee, Linda Sanders, Sushil Kumar, Ari B. Molofsky, Kurt R. Stenmark, Dean Sheppard, Rubin M. Tuder, Mohit D. Gupta, Tashi Thinlas, Qadar Pasha, Brian B. Graham
Abstract
The pathogenesis of thoracic aortic aneurysm (TAA) in Marfan syndrome (MFS) is generally attributed to vascular smooth muscle cell (VSMC) pathologies. However, the role of immune cell–mediated inflammation remains elusive. Single-cell RNA sequencing identified a subset of CX3CR1+ macrophages mainly located in the intima in the aortic roots and ascending aortas of Fbn1C1041G/+ mice, further validated in MFS patients. Specific elimination of CX3CR1+ cells by diphtheria toxin in Cx3cr1-CreERT2iDTRF/+Fbn1C1041G/+ mice efficiently ameliorated TAA progression. Administering the monoclonal antibodies to respectively neutralize TNF-α and IGF1 produced by CX3CR1+ cells from MFS patients greatly suppressed the cocultured MFS patient–specific induced pluripotent stem cell–derived VSMC inflammation. BM transplantation and parabiosis revealed that CX3CR1+ macrophages are mainly originated from BM-derived monocytes. Targeting TNF-α and IGF1 in CX3CR1+ macrophages via shRNA lentivirus transduction in BM cells efficiently suppressed TAA development in BM-transplanted Fbn1C1041G/+ mice. Application of the CCR2 antagonist RS504393 to inhibit monocyte infiltration markedly reduced the accumulation of CX3CR1+ macrophages and subsequently alleviated TAA progression in Fbn1C1041G/+ mice. In summary, CX3CR1+ macrophages mainly located in aortic intima mediate TAA formation by paracrinally causing VSMC inflammation, and targeting them offers a potential antiinflammatory therapeutic strategy for MFS-related TAA.
Authors
Jiaqi Huang, Hao Liu, Zhujiang Liu, Zhenting Wang, Hanshi Xu, Zhuofan Li, Shan Huang, Xueyuan Yang, Yicong Shen, Fang Yu, Yulin Li, Junming Zhu, Wei Li, Li Wang, Wei Kong, Yi Fu
Abstract
Type-2 innate lymphoid cells (ILC2s) play a pivotal role in the development of airway hyperreactivity (AHR). However, the regulatory mechanisms governing ILC2 function remain inadequately explored. This study uncovers V-domain Ig suppressor of T cell activation (VISTA) as an inhibitory immune checkpoint crucial for modulating ILC2-driven lung inflammation. VISTA is upregulated in activated pulmonary ILC2s and plays a key role in regulating lung inflammation, as VISTA-deficient ILC2s demonstrate increased proliferation and function, resulting in elevated type-2 cytokine production and exacerbation of AHR. Mechanistically, VISTA stimulation activates Forkhead box O1 (FOXO1), leading to modulation of ILC2 proliferation and function. The suppressive effects of FOXO1 on ILC2 effector function were confirmed using FOXO1 inhibitors and activators. Moreover, VISTA-deficient ILC2s exhibit enhanced fatty acid oxidation and oxidative phosphorylation to meet their high energy demands. Therapeutically, VISTA agonist treatment reduces ILC2 function both ex vivo and in vivo, significantly alleviating ILC2-driven AHR. Our murine findings were validated in human ILC2s, where a VISTA agonist reduces their function ex vivo and in a humanized mouse model of ILC2-driven AHR. Our studies unravel VISTA as an immune checkpoint for ILC2 regulation via the FOXO1 pathway, presenting potential therapeutic strategies for allergic asthma by modulating ILC2 responses.
Authors
Mohammad Hossein Kazemi, Zahra Momeni-Varposhti, Xin Li, Benjamin P. Hurrell, Yoshihiro Sakano, Stephen Shen, Pedram Shafiei-Jahani, Kei Sakano, Omid Akbari
Abstract
Various factors play key roles in maintaining intestine homeostasis. Disruption of the balance may lead to intestinal inflammatory diseases (IBDs) and even colorectal cancer (CRC). Loss or gain of function of many key proteins can result in dysregulated intestinal homeostasis. Our research demonstrated that neural precursor cells expressed developmentally down-regulated 4-like protein, NEDD4L (NEDD4-2), a type of HECT family E3 ubiquitin ligase, played an important role in maintaining intestinal homeostasis. NEDD4L expression was significantly inhibited in intestinal epithelial cells (IECs) of patients with Crohn's disease (CD), ulcerative colitis (UC), and CRC. Global knockout of NEDD4L or its deficiency in IECs exacerbated dextran sulfate sodium (DSS)-/2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis and azoxymethane (AOM)/DSS-induced colorectal cancer. Mechanistically, NEDD4L deficiency in IECs inhibited the key ferroptosis regulator glutathione peroxidase 4 (GPX4) expression by reducing the protein expression of solute carrier family 3 member 2 (SLC3A2) without affecting its gene expression, ultimately promoting DSS-induced IEC ferroptosis. Importantly, ferroptosis inhibitors reduced the susceptibility of NEDD4L-deficient mice to colitis and colitis-associated colorectal cancer (CAC). Thus, NEDD4L was an important regulator in IEC ferroptosis, maintaining intestinal homeostasis, making it a potential clinical target for diagnosing and treating IBDs.
Authors
Jingjing Liang, Ning Wang, Yihan Yao, Yingmei Wang, Xiang An, Haofei Wang, Huan Liu, Yu Jiang, Hui Li, Xiaoqing Cheng, Jiaqi Xu, Xiaojing Liang, Jun Lou, Zengfeng Xin, Ting Zhang, Xiaojian Wang, Wenlong Lin
Abstract
Red blood cells (RBCs), traditionally recognized for their role in transporting oxygen, play a pivotal role in the body's immune response by expressing TLR9 and scavenging excess host cell-free DNA. DNA capture by RBCs leads to accelerated RBC clearance and triggers inflammation. Whether RBCs can also acquire microbial DNA during infections is unknown. Murine RBCs acquire microbial DNA in vitro and bacterial-DNA-induced macrophage activation was augmented by WT but not Tlr9-deleted RBCs. In a mouse model of polymicrobial sepsis, RBC-bound bacterial DNA was elevated in WT but not in erythroid Tlr9-deleted mice. Plasma cytokine analysis in these mice revealed distinct sepsis clusters characterized by persistent hypothermia and hyperinflammation in the most severely affected subjects. RBC-Tlr9 deletion attenuated plasma and tissue IL-6 production in the most severe group. Parallel findings in human subjects confirmed that RBCs from septic patients harbored more bacterial DNA compared to healthy individuals. Further analysis through 16S sequencing of RBC-bound DNA illustrated distinct microbial communities, with RBC-bound DNA composition correlating with plasma IL-6 in patients with sepsis. Collectively, these findings unveil RBCs as overlooked reservoirs and couriers of microbial DNA, capable of influencing host inflammatory responses in sepsis.
Authors
LK Metthew Lam, Nathan J. Klingensmith, Layal Sayegh, Emily Oatman, Joshua S. Jose, Christopher V. Cosgriff, Kaitlyn A. Eckart, John McGinnis, Piyush Ranjan, Matthew Lanza, Nadir Yehya, Nuala J. Meyer, Robert P. Dickson, Nilam S. Mangalmurti
Abstract
Dysregulations of epithelial-immune interactions frequently culminate in chronic inflammatory diseases of the skin, lungs, kidneys, and gastrointestinal tract. Yet, the intraepithelial processes which initiate and perpetuate inflammation in these organs are poorly understood. Here, by utilizing redox lipidomics we identified ferroptosis-associated peroxidation of polyunsaturated phosphatidylethanolamines in the epithelia of patients with asthma, cystic fibrosis, psoriasis and renal failure. Focusing on psoriasis as a disease model, we used high-resolution mass spectrometry imaging and identified keratin 14 (K14)-expressing keratinocytes executing a ferroptotic death program in human psoriatic skin. Psoriatic phenotype with characteristic Th1/Th17 skin and extracutaneous immune responses was initiated and maintained in a murine model designed to actuate ferroptosis in a fraction of K14+ glutathione peroxidase 4 (Gpx4)-deficient epidermal keratinocytes. Importantly, an anti-ferroptotic agent, Liproxstatin-1, was as effective as clinically relevant biologic IL-12/IL-23/TNFα-targeting therapies or the depletion of T cells in completely abrogating molecular, biochemical and morphologic features of psoriasis. As ferroptosis in select epidermal keratinocytes triggers and sustains a pathologic psoriatic multi-organ inflammatory circuit, we suggest that strategies targeting ferroptosis, or its causes, may be effective in preventing or ameliorating a variety of chronic inflammatory diseases.
Authors
Kavita Vats, Hua Tian, Kunal Singh, Yulia Y. Tyurina, Louis J. Sparvero, Vladimir A. Tyurin, Oleg Kruglov, Alexander Chang, Jiefei Wang, Felicia Green, Svetlana N. Samovich, Jiying Zhang, Ansuman Chattopadhyay, Natalie Murray, Vrusha K. Shah, Alicia R. Mathers, Uma R. Chandran, Joseph M. Pilewski, John A. Kellum, Sally E. Wenzel, Hülya Bayir, Valerian E. Kagan, Yuri L. Bunimovich
Abstract
Tissue regeneration is orchestrated by macrophages that clear damaged cells and promote regenerative inflammation. How macrophages spatially adapt and diversify their functions to support the architectural requirements of actively regenerating tissue remains unknown. In this study, we reconstructed the dynamic trajectories of myeloid cells isolated from acutely injured and early-stage dystrophic muscles. We identified divergent subsets of monocytes/macrophages and dendritic cells (DCs) and validated markers (e.g., GPNMB) and transcriptional regulators associated with defined functional states. In dystrophic muscle, specialized repair-associated subsets exhibited distinct macrophage diversity and reduced DC heterogeneity. Integrating spatial transcriptomics analyses with immunofluorescence uncovered the ordered distribution of subpopulations and multilayered regenerative inflammation zones (RIZs) where distinct macrophage subsets are organized in functional zones around damaged myofibers supporting all phases of regeneration. Importantly, intermittent glucocorticoid treatment disrupted the RIZs. Our findings suggest that macrophage subtypes mediated the development of the highly ordered architecture of regenerative tissues, unveiling the principles of the structured yet dynamic nature of regenerative inflammation supporting effective tissue repair.
Authors
Andreas Patsalos, Laszlo Halasz, Darby Oleksak, Xiaoyan Wei, Gergely Nagy, Petros Tzerpos, Thomas Conrad, David W. Hammers, H. Lee Sweeney, Laszlo Nagy
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ISSN: 0021-9738 (print), 1558-8238 (online)