HLA-B*27 was one of the first HLA alleles associated with an autoimmune disease, i.e., axial spondyloarthritis (axSpA) and acute anterior uveitis (B27AAU), which cause joint and eye inflammation, respectively. Gastrointestinal inflammation has been suggested as a trigger of axSpA. We recently identified a bacterial peptide (YeiH) that can be presented by HLA-B*27 to expanded public T cell receptors (TCRs) in the joint in axSpA and the eye in B27AAU. While YeiH is present in enteric microbiota and pathogens, additional evidence that pathogenic T cells in HLA-B*27-associated autoimmunity may have had a prior antigenic encounter within the gastrointestinal tract remains lacking. Here, we analyze ocular, synovial, and blood T cells in B27AAU and axSpA, showing that YeiH-specific CD8 T cells express a mucosal gene set and surface proteins consistent with intestinal differentiation, including CD161, integrin α4β7, and CCR6. In addition, we find an expansion of YeiH-specific CD8 T cells in the blood of axSpA and B27AAU over healthy controls, whereas influenza-specific CD8 T cells were equivalent across groups. Lastly, we demonstrate the dispensability of TRBV9 for antigen recognition. Collectively, our data suggest that, in HLA-B27-associated autoimmunity, early antigen exposure and differentiation of pathogenic CD8 T cells may occur in enteric organs.
Michael A. Paley, Xinbo Yang, Lynn M. Hassman, Frank Penkava, Lee I. Garner, Grace L. Paley, Nicole Linskey, Ryan Agnew, Paulo Henrique Arantes de Faria, Annie Feng, Sophia Y. Li, Davide Simone, Elisha D.O. Roberson, Philip A. Ruzycki, Ekaterina Esaulova, Jennifer Laurent, Lacey Feigl-Lenzen, Luke E. Springer, Chang Liu, Geraldine M. Gillespie, Paul Bowness, K. Christopher Garcia, Wayne M. Yokoyama
Gain-of-function mutations in the dsDNA sensing adaptor STING lead to a severe autoinflammatory syndrome known as STING-associated vasculopathy with onset in Infancy (SAVI). SAVI patients develop interstitial lung disease (ILD) and produce autoantibodies that are commonly associated with systemic autoimmune diseases. Mice expressing the most common SAVI mutation STING V154M (VM) similarly develop ILD, but exhibit severe T and B cell lymphopenia, low serum Ig titers, and lack autoantibodies. Importantly, lethally irradiated VM hosts reconstituted with wildtype (WT) stem cells (WT→VM) still develop ILD. In this study, we find that WT→VM chimeras had restored B cell function, produced autoantibodies, and thereby recapitulated the loss of tolerance seen in SAVI patients. Lymphocytes derived from both WT and BCR or TCR transgenic (Tg) donors accumulated in the extravascular lung tissue of WT+Tg→VM mixed chimeras, but lymphocyte activation and germinal center formation required WT cells with a diverse repertoire. Furthermore, when T cells isolated from the WTVM chimeras were adoptively transferred to naïve Rag1-deficient 2º hosts, they trafficked to the lung and recruited neutrophils. Overall, these findings indicated that VM expression by radioresistant cells promoted the activation of autoreactive B cells and T cells that then differentiated into potentially pathogenic effector subsets.
Kevin MingJie Gao, Kristy Chiang, Sharon Subramanian, Xihui Yin, Paul J. Utz, Kerstin Nündel, Kate A. Fitzgerald, Ann Marshak-Rothstein
Type 2 diabetes (T2D) is on the rise worldwide and is associated with various complications of the oral cavity. Using an adult-onset diabetes preclinical model, we demonstrated profound periodontal alterations in T2D mice, including inflamed gingiva, disintegrated periodontal ligaments (PDL), marked alveolar bone loss, and unbalanced bone remodeling due to decreased formation and increased resorption. Notably, we observed elevated levels of the Wnt signaling inhibitor sclerostin in the alveolar bone of T2D mice. Motivated by these findings, we investigated whether a sclerostin-neutralizing antibody (Scl-Ab) could rescue the compromised periodontium in T2D mice. Administering Scl-Ab subcutaneously once a week for four weeks, starting four weeks after T2D induction, led to substantial increases in bone mass. This effect was attributed to the inhibition of osteoclasts and promotion of osteoblasts in both control and T2D mice, effectively reversing the bone loss caused by T2D. Furthermore, Scl-Ab stimulated PDL cell proliferation, partially restored the PDL fibers, and mitigated inflammation in the periodontium. Our study thus established a T2D-induced periodontitis mouse model characterized by inflammation and tissue degeneration. Scl-Ab emerged as a promising intervention to counteract the detrimental effects of T2D on the periodontium, exhibiting limited side effects on other craniofacial hard tissues.
Hakan Turkkahraman, Shannan Flanagan, Tianli Zhu, Nisreen Akel, Silvia Marino, Dayane Ortega-Gonzalez, Xue Yuan, Teresita M. Bellido
Abdominal aortic aneurysm (AAA) is one of the most life-threatening cardiovascular diseases; however, effective drug treatments are still lacking. The formation of neutrophil extracellular traps (NETs) has been shown to be crucial trigger of AAA and identifying upstream regulatory targets is thus key to discovering therapeutic agents for AAA. We revealed that phosphoinositide 3-kinase gamma (PI3Kγ) acted as an upstream regulatory molecule, and that PI3Kγ inhibition reduced NET formation and aortic wall inflammation, thereby markedly ameliorating AAA. However, the mechanism of NET formation regulated by PI3Kγ remains unclear. In this study, we showed that PI3Kγ deficiency inactivated the noncanonical pyroptosis pathway, which suppressed downstream NET formation. In addition, PI3Kγ regulation of noncanonical pyroptosis was dependent on cAMP/protein kinase A (cAMP/PKA) signaling. These results clarify the molecular mechanism and crosstalk between PI3Kγ and NETosis in the development of AAA, potentially facilitating the discovery of therapeutic options for AAA.
Yacheng Xiong, Shuai Liu, Yu Liu, Jiani Zhao, Jinjian Sun, Yongqing Li, Baihong Pan, Wei Wang
To determine whether hyperlipidemia and chronic kidney disease (CKD) have a synergy in accelerating vascular inflammation via trained immunity (TI), we performed aortic pathological analysis and RNA-sequencing of high-fat diet (HFD)-fed 5/6 nephrectomy CKD (HFD+CKD) mice. We made the following findings: 1) HFD+CKD increased aortic cytosolic lipopolysaccharide (LPS) levels, caspase-11 (CASP11) activation, and 998 gene expressions of TI pathways in the aorta (first-tier TI mechanism); 2) CASP11–/– decreased aortic neointima hyperplasia, aortic recruitment of macrophages, and casp11-gasdermin D-mediated cytokine secretion; 3) CASP11–/– decreased N-terminal gasdermin D (N-GSDMD) membrane expression on aortic endothelial cells and aortic IL-1B levels; 4) LPS transfection into human aortic endothelial cells resulted in CASP4 (human)/CASP11 (mouse) activation and increased N-GSDMD membrane expression; 5) IL-1B served as the second-tier mechanism underlying HFD+CKD-promoted TI. Taken together, hyperlipidemia and CKD accelerated vascular inflammation by promoting two-tier trained immunity.
Yu Sun, Yifan Lu, Lu Liu, Fatma Saaoud, Ying Shao, Keman Xu, Charles Drummer IV, Ramon Cueto, Huimin Shan, Xiaohua Jiang, Huaqing Zhao, Hong Wang, Xiaofeng Yang
Fibrosis in the lung is thought to be driven by epithelial cell dysfunction and aberrant cell-cell interactions. Unveiling the molecular mechanisms of cellular plasticity and cell-cell interactions is imperative to elucidate lung regenerative capacity and aberrant repair in pulmonary fibrosis. By mining publicly available RNA-seq datasets, we identified loss of CCAAT enhancer-binding protein alpha (CEBPA) as a candidate contributor to idiopathic pulmonary fibrosis (IPF). We used conditional knockout mice, scRNA-seq, lung organoids, small-molecule inhibition and novel gene manipulation methods to investigate the role of CEBPA in lung fibrosis and repair. Long term (6 month+) of Cebpa loss in AT2 cells caused spontaneous fibrosis and increased susceptibility to bleomycin-induced fibrosis. Cebpa knockout in these mice significantly decreased AT2 cell numbers in the lung and reduced expression of surfactant homeostasis genes, while increasing inflammatory cell recruitment as well as upregulating S100a8/a9 in AT2 cells. In vivo treatment with an S100A8/A9 inhibitor alleviated experimental lung fibrosis. Restoring CEBPA expression in lung organoids ex vivo and during experimental lung fibrosis in vivo rescued CEBPA deficiency-mediated phenotypes. Our study establishes a direct mechanistic link between CEBPA repression, impaired AT2 cell identity, disrupted tissue homeostasis, and lung fibrosis.
Qi Tan, Jack H. Wellmerling, Shengren Song, Sara R. Dresler, Jeffrey A. Meridew, Kyoung M. Choi, Yong Li, Y.S. Prakash, Daniel J. Tschumperlin
Antifibrotic therapy with nintedanib is the clinical mainstay in the treatment of progressive fibrosing interstitial lung disease (ILD). High-dimensional medical image analysis, known as radiomics, provides quantitative insights into organ-scale pathophysiology, generating digital disease fingerprints. Here, we used an integrative analysis of radiomic and proteomic profiles (radioproteomics) to assess whether changes in radiomic signatures can stratify the degree of antifibrotic response to nintedanib in (experimental) fibrosing ILD. Unsupervised clustering of delta radiomic profiles revealed two distinct imaging phenotypes in mice treated with nintedanib, contrary to conventional densitometry readouts, which showed a more uniform response. Integrative analysis of delta radiomics and proteomics demonstrated that these phenotypes reflected different treatment response states, as further evidenced on transcriptional and cellular levels. Importantly, radioproteomics signatures paralleled disease- and drug related biological pathway activity with high specificity, including extracellular matrix (ECM) remodeling, cell cycle activity, wound healing, and metabolic activity. Evaluation of the preclinical molecular response-defining features, particularly those linked to ECM remodeling, in a cohort of nintedanib-treated fibrosing ILD patients, accurately stratified patients based on their extent of lung function decline. In conclusion, delta radiomics has great potential to serve as a non-invasive and readily accessible surrogate of molecular response phenotypes in fibrosing ILD. This could pave the way for personalized treatment strategies and improved patient outcomes.
David Lauer, Cheryl Y. Magnin, Luca R. Kolly, Huijuan Wang, Matthias Brunner, Mamta Chabria, Grazia M. Cereghetti, Hubert S. Gabryś, Stephanie Tanadini-Lang, Anne-Christine Uldry, Manfred Heller, Stijn E. Verleden, Kerstin Klein, Adela-Cristina Sarbu, Manuela Funke-Chambour, Lukas Ebner, Oliver Distler, Britta Maurer, Janine Gote-Schniering
Carcinomas are common in humans but rare among closely related “great apes”. Plausible explanations, including human-specific genomic alterations affecting the biology of sialic acids are proposed, but causality remains unproven. Here, an integrated evolutionary genetics-phenome-transcriptome approach studied the role of SIGLEC12 gene (encodes Siglec-XII) on epithelial transformation and cancer. Exogenous expression of the protein in cell lines and genetically engineered mice recapitulated ~30% of the human population in whom the protein is expressed in a form that cannot bind ligand due to a fixed, homozygous, human-universal missense mutation. Siglec-XII null cells/mice recapitulated the remaining ~70% of the human population in whom an additional polymorphic frameshift mutation eliminates the entire protein. Siglec-XII expression drove several pro-oncogenic phenotypes in cell lines, and increased tumor burden in mice challenged with chemical carcinogen and inflammation. Transcriptomic studies yielded a 29-gene signature of Siglec-XII-positive disease and when used as a computational tool for navigating human datasets, pinpointed with surprising precision that SIGLEC12 expression (model) recapitulates a very specific type of colorectal carcinomas (disease) that is associated with mismatch-repair defects and inflammation, disproportionately affects European-Americans, and carries a better prognosis. They revealed a hitherto unknown evolutionary genetic mechanism for an ethnic/environmental predisposition of carcinogenesis.
Hector A. Cuello, Saptarshi Sinha, Andrea L. Verhagen, Nissi Varki, Ajit Varki, Pradipta Ghosh
Clarifying multifactorial musculoskeletal disorder etiologies supports risk analysis and development of targeted prevention and treatment modalities. Deep learning enables comprehensive risk factor identification through systematic analysis of disease datasets but does not provide sufficient context for mechanistic understanding, limiting clinical applicability for etiological investigations. Conversely, multiscale biomechanical modeling can evaluate mechanistic etiology within the relevant biomechanical and physiological context. We propose a hybrid approach combining 3D explainable deep learning and multiscale biomechanical modeling; we applied this approach to investigate temporomandibular joint (TMJ) disorder etiology by systematically identifying risk factors and elucidating mechanistic relationships between risk factors and TMJ biomechanics and mechanobiology. Our 3D convolutional neural network recognized TMJ disorder patients through subject-specific morphological features in condylar, ramus, and chin. Driven by deep learning model outputs, biomechanical modeling revealed that small mandibular size and flat condylar shape were associated with increased TMJ disorder risk through increased joint force, decreased tissue nutrient availability and cell ATP production, and increased TMJ disc strain energy density. Combining explainable deep learning and multiscale biomechanical modeling addresses the “mechanism unknown” limitation undermining translational confidence in clinical applications of deep learning and increases methodological accessibility for smaller clinical datasets by providing the crucial biomechanical context.
Shuchun Sun, Pei Xu, Nathan Buchweitz, Cherice N. Hill, Farhad Ahmadi, Marshall B. Wilson, Angela Mei, Xin She, Benedikt Sagl, Elizabeth H. Slate, Janice S. Lee, Yongren Wu, Hai Yao
The Neurofibromatosis Type 1 (NF1) RASopathy is associated with persistent fibrotic nonunions (pseudarthrosis) in human and mouse skeletal tissue. Here, we first performed spatial transcriptomics to define the molecular signatures across normal endochondral healing following fracture in mice. Within the control fracture callus, we observed spatially restricted activation of morphogenetic pathways, such as TGF-β, WNT, and BMP. To investigate the molecular mechanisms contributing to Nf1-deficient delayed fracture healing, we performed spatial transcriptomic analysis on a Postn-cre;Nf1flox/- (Nf1Postn) fracture callus. Transcriptional analyses, subsequently confirmed through p-SMAD1/5/8 immunohistochemistry, demonstrated a lack of BMP pathway induction in Nf1Postn mice. To further inform the human disease, we performed spatial transcriptomic analysis of fracture pseudarthrosis tissue from a NF1 patient. Analyses detected increased MAPK signaling at the fibrocartilaginous-osseus junction. Similar to the Nf1Postn fracture, BMP pathway activation was absent within the pseudarthrosis tissue. Our results demonstrate the feasibility to delineate the molecular and tissue-specific heterogeneity inherent in complex regenerative processes, such as fracture healing, and to reconstruct phase transitions representing endochondral bone formation in vivo. Furthermore, our results provide in situ molecular evidence of impaired BMP signaling underlying NF1 pseudarthrosis, potentially informing the clinical relevance of off-label BMP2 as a therapeutic intervention.
Jonathan J. Rios, Conan Juan, John M. Shelton, Nandina Paria, Ila Oxendine, Meghan Wassell, Yared H. Kidane, Reuel Cornelia, Elise C. Jeffery, David A. Podeszwa, Simon J. Conway, Carol A. Wise, Robert J. Tower
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