Connexin-45 is expressed in mouse lymphatic endothelium and required for lymphatic valve function

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Abstract

The expression and functional relevance of the gap junction molecule connexin-45 (Cx45; GJC1) in lymphatic endothelium were not previously known. We found that Cx45 was expressed widely in the endothelium of murine lymphatics, in both valve and nonvalve regions. Cell-specific deletion of Cx45, driven by a constitutive Cre line (Lyve1-Cre) or an inducible Cre line (Prox1-CreERT2), compromised the function of lymphatic valves, as assessed by physiological tests (back leak and closure) of isolated, single-valve vessel segments. The defects were comparable to those previously reported for loss of Cx43, and as with Cx43, deletion of Cx45 resulted in shortening or increased asymmetry of lymphatic valve leaflets, providing an explanation for the compromised valve function. In contrast with Cx43, lymphatic endothelial cell–specific (LEC-specific) deletion of Cx45 did not alter the number of valves in mesenteric or dermal lymphatic networks or the expression patterns of the canonical valve-associated proteins PROX1, ITGA9, or CLAUDIN5. Constitutive deletion of Cx45 from LECs resulted in increased backflow of injected tracer in popliteal networks in vivo and compromised the integrity of the LEC permeability barrier in a subset of collecting vessels. These findings provide evidence for an unexpected role of Cx45 in the development and maintenance of lymphatic valves.

Authors

Michael J. Davis, Jorge A. Castorena-Gonzalez, Min Li, Scott D. Zawieja, Alex M. Simon, Xin Geng, R. Sathish Srinivasan

Activation of autoreactive lymphocytes in the lung by radioresistant cells expressing a STING gain-of-function mutation

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Abstract

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). Patients with SAVI 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 and low serum Ig titers, and they lack autoantibodies. Importantly, lethally irradiated VM hosts reconstituted with 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 patients with SAVI. 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 WT→VM chimeras were adoptively transferred to naive Rag1-deficient secondary 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.

Authors

Kevin MingJie Gao, Kristy Chiang, Sharon Subramanian, Xihui Yin, Paul J. Utz, Kerstin Nündel, Kate A. Fitzgerald, Ann Marshak-Rothstein

Mucosal signatures of pathogenic T cells in HLA-B*27⁺ anterior uveitis and axial spondyloarthritis

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Abstract

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 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 analyzed 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 found an expansion of YeiH-specific CD8+ T cells in axSpA and B27AAU blood compared with that from individuals acting as healthy controls, whereas influenza-specific CD8+ T cells were equivalent across groups. Finally, we demonstrated 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.

Authors

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

Thrombospondin-1 promotes fibro-adipogenic stromal expansion and contractile dysfunction of the diaphragm in obesity

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Abstract

Pulmonary disorders affect 40%–80% of individuals with obesity. Respiratory muscle dysfunction is linked to these conditions; however, its pathophysiology remains largely undefined. Mice subjected to diet-induced obesity (DIO) develop diaphragm muscle weakness. Increased intradiaphragmatic adiposity and extracellular matrix (ECM) content correlate with reductions in contractile force. Thrombospondin-1 (THBS1) is an obesity-associated matricellular protein linked with muscular damage in genetic myopathies. THBS1 induces proliferation of fibro-adipogenic progenitors (FAPs) — mesenchymal cells that differentiate into adipocytes and fibroblasts. We hypothesized that THBS1 drives FAP-mediated diaphragm remodeling and contractile dysfunction in DIO. We tested this by comparing the effects of dietary challenge on diaphragms of wild-type (WT) and Thbs1-knockout (Thbs1–/–) mice. Bulk and single-cell transcriptomics demonstrated DIO-induced stromal expansion in WT diaphragms. Diaphragm FAPs displayed upregulation of ECM and TGF-β–related expression signatures and augmentation of a Thy1-expressing subpopulation previously linked to type 2 diabetes. Despite similar weight gain, Thbs1–/– mice were protected from these transcriptomic changes and from obesity-induced increases in diaphragm adiposity and ECM deposition. Unlike WT controls, Thbs1–/– diaphragms maintained normal contractile force and motion after DIO challenge. THBS1 is therefore a necessary mediator of diaphragm stromal remodeling and contractile dysfunction in overnutrition and a potential therapeutic target in obesity-associated respiratory dysfunction.

Authors

Eric D. Buras, Moon-Sook Woo, Romil Kaul Verma, Sri Harshita Kondisetti, Carol S. Davis, Dennis R. Claflin, Kimber Converso-Baran, Daniel E. Michele, Susan V. Brooks, Tae-Hwa Chun

High-fat and high-carbohydrate diets increase bone fragility through TGF-β–dependent control of osteocyte function

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Abstract

Obesity can increase the risk of bone fragility, even when bone mass is intact. This fragility stems from poor bone quality, potentially caused by deficiencies in bone matrix material properties. However, cellular and molecular mechanisms leading to obesity-related bone fragility are not fully understood. Using male mouse models of obesity, we discovered TGF-β signaling plays a critical role in mediating the effects of obesity on bone. High-carbohydrate and high-fat diets increase TGF-β signaling in osteocytes, which impairs their mitochondrial function, increases cellular senescence, and compromises perilacunar/canalicular remodeling and bone quality. By specifically inhibiting TGF-β signaling in mouse osteocytes, some of the negative effects of high-fat and high-carbohydrate diets on bones, including the lacunocanalicular network, perilacunar/canalicular remodeling, senescence, and mechanical properties such as yield stress, were mitigated. DMP1-Cre–mediated deletion of TGF-β receptor II also blunted adverse effects of high-fat and high-carbohydrate diets on energy balance and metabolism. These findings suggest osteocytes are key in controlling bone quality in response to high-fat and high-carbohydrate diets. Calibrating osteocyte function could mitigate bone fragility associated with metabolic diseases while reestablishing energy balance.

Authors

Neha S. Dole, Andrés Betancourt-Torres, Serra Kaya, Yoshihiro Obata, Charles A. Schurman, Jihee Yoon, Cristal S. Yee, Vivek Khanal, Clarissa Aguirre Luna, Madeline Carroll, Jennifer J. Salinas, Elizabeth Miclau, Claire Acevedo, Tamara Alliston

Targeting CEBPA to restore cellular identity and tissue homeostasis in pulmonary fibrosis

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Abstract

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 elucidating lung regenerative capacity and aberrant repair in pulmonary fibrosis. By mining publicly available RNA-Seq data sets, we identified loss of CCAAT enhancer-binding protein alpha (CEBPA) as a candidate contributor to idiopathic pulmonary fibrosis (IPF). We used conditional KO mice, scRNA-Seq, lung organoids, small-molecule inhibition, and potentially novel gene manipulation methods to investigate the role of CEBPA in lung fibrosis and repair. Long-term (6 months or more) of Cebpa loss in AT2 cells caused spontaneous fibrosis and increased susceptibility to bleomycin-induced fibrosis. Cebpa knockout (KO) 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.

Authors

Qi Tan, Jack H. Wellmerling, Shengren Song, Sara R. Dresler, Jeffrey A. Meridew, Kyoung M. Choi, Yong Li, Y.S. Prakash, Daniel J. Tschumperlin

Spatial transcriptomics implicates impaired BMP signaling in NF1 fracture pseudarthrosis in murine and patient tissues

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Abstract

The neurofibromatosis type 1 (NF1) RASopathy is associated with persistent fibrotic nonunions (pseudarthrosis) in human and mouse skeletal tissue. Here, we performed spatial transcriptomics to define the molecular signatures occurring during 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;Nf1fl/– (Nf1Postn) fracture callus. Transcriptional analyses, subsequently confirmed through phospho-SMAD1/5/8 immunohistochemistry, demonstrated a lack of BMP pathway induction in Nf1Postn mice. To gain further insight into the human condition, we performed spatial transcriptomic analysis of fracture pseudarthrosis tissue from a patient with NF1. Analyses detected increased MAPK signaling at the fibrocartilaginous-osseus junction. Similar to that in the Nf1Postn fracture, BMP pathway activation was absent within the pseudarthrosis tissue. Our results demonstrate the feasibility of delineating the molecular and tissue-specific heterogeneity inherent in complex regenerative processes, such as fracture healing, and reconstructing 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.

Authors

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

NAD⁺ precursors prolong survival and improve cardiac phenotypes in a mouse model of Friedreich’s Ataxia

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Abstract

Friedreich’s ataxia (FRDA) is a progressive disorder caused by insufficient expression of frataxin, which plays a critical role in assembly of iron-sulfur centers in mitochondria. Individuals are cognitively normal but display a loss of motor coordination and cardiac abnormalities. Many ultimately develop heart failure. Administration of nicotinamide adenine dinucleotide–positive (NAD+) precursors has shown promise in human mitochondrial myopathy and rodent models of heart failure, including mice lacking frataxin in cardiomyocytes. We studied mice with systemic knockdown of frataxin (shFxn), which display motor deficits and early mortality with cardiac hypertrophy. Hearts in these mice do not “fail” per se but become hyperdynamic with small chamber sizes. Data from an ongoing natural history study indicate that hyperdynamic hearts are observed in young individuals with FRDA, suggesting that the mouse model could reflect early pathology. Administering nicotinamide mononucleotide or riboside to shFxn mice increases survival, modestly improves cardiac hypertrophy, and limits increases in ejection fraction. Mechanistically, most of the transcriptional and metabolic changes induced by frataxin knockdown are insensitive to NAD+ precursor administration, but glutathione levels are increased, suggesting improved antioxidant capacity. Overall, our findings indicate that NAD+ precursors are modestly cardioprotective in this model of FRDA and warrant further investigation.

Authors

Caroline E. Perry, Sarah M. Halawani, Sarmistha Mukherjee, Lucie V. Ngaba, Melissa Lieu, Won Dong Lee, James G. Davis, Gabriel K. Adzika, Alyssa N. Bebenek, Daniel D. Bazianos, Beishan Chen, Elizabeth Mercado-Ayon, Liam P. Flatley, Arjun P. Suryawanshi, Isabelle Ho, Joshua D. Rabinowitz, Suraj D. Serai, David M. Biko, Jaclyn Tamaroff, Anna DeDio, Kristin Wade, Kimberly Y. Lin, David J. Livingston, Shana E. McCormack, David R. Lynch, Joseph A. Baur

Caspase-4/11 promotes hyperlipidemia and chronic kidney disease–accelerated vascular inflammation by enhancing trained immunity

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Abstract

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-Seq of high-fat diet–fed (HFD-fed) 5/6 nephrectomy CKD (HFD+CKD) mice. We made the following findings: (a) HFD+CKD increased aortic cytosolic LPS levels, caspase-11 (CASP11) activation, and 998 gene expressions of TI pathways in the aorta (first-tier TI mechanism); (b) CASP11–/– decreased aortic neointima hyperplasia, aortic recruitment of macrophages, and casp11–gasdermin D–mediated cytokine secretion; (c) CASP11–/– decreased N-terminal gasdermin D (N-GSDMD) membrane expression on aortic endothelial cells and aortic IL-1B levels; (d) LPS transfection into human aortic endothelial cells resulted in CASP4 (human)/CASP11 (mouse) activation and increased N-GSDMD membrane expression; and (e) IL-1B served as the second-tier mechanism underlying HFD+CKD-promoted TI. Taken together, hyperlipidemia and CKD accelerated vascular inflammation by promoting 2-tier trained immunity.

Authors

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

Evaluating precision medicine approaches for gene therapy in patient-specific cellular models of Bietti crystalline dystrophy

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Abstract

Patient-specific induced pluripotent stem cell–derived (iPSC-derived) cell lines allow for therapies to be tailored to individual patients, increasing therapeutic precision and efficiency. Bietti crystalline dystrophy (BCD) is a rare blinding disease estimated to affect about 67,000 individuals worldwide. Here, we used iPSC-derived retinal pigment epithelium (iRPE) cells from patients with BCD to evaluate adeno-associated virus–mediated (AAV-mediated) gene augmentation therapy strategies. We found that BCD iRPE cells were vulnerable to blue light–induced oxidative stress and that cellular phenotype can be quantified using 3 robust biomarkers: reactive oxygen species (ROS), 4-hydroxy 2-nonenal (4-HNE) levels, and cell death rate. Additionally, we demonstrated that AAV-mediated gene therapy can significantly reduce light-induced cell death in BCD iRPE cells. This is the first proof-of-concept study to our knowledge to show that AAV-CYP4V2 gene therapy can be used to treat light-induced RPE damage in BCD. Furthermore, we observed significant variability in cellular phenotypes among iRPE from patients with BCD of divergent mutations, which outlined genotype-phenotype correlations in BCD patient–specific cell disease models. Our results reveal that patient-specific iRPE cells retained personalized responses to AAV-mediated gene therapy. Therefore, this approach can advance BCD therapy and set a precedent for precision medicine in other diseases, emphasizing the necessity for personalization in healthcare to accommodate individual diversity.

Authors

Yao Li, Richard R. Yang, Yong-Shi Li, Chun-Wei Hsu, Laura A. Jenny, Yang Kong, Merry Z.C. Ruan, Janet R. Sparrow, Stephen H. Tsang

Single-cell RNA-Seq analysis reveals cell subsets and gene signatures associated with rheumatoid arthritis disease activity

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Abstract

Rheumatoid arthritis (RA) management leans toward achieving remission or low disease activity. In this study, we conducted single-cell RNA sequencing (scRNA-Seq) of peripheral blood mononuclear cells (PBMCs) from 36 individuals (18 patients with RA and 18 matched controls, accounting for age, sex, race, and ethnicity), to identify disease-relevant cell subsets and cell type–specific signatures associated with disease activity. Our analysis revealed 18 distinct PBMC subsets, including an IFN-induced transmembrane 3–overexpressing (IFITM3-overexpressing) IFN-activated monocyte subset. We observed an increase in CD4+ T effector memory cells in patients with moderate-high disease activity (DAS28-CRP ≥ 3.2) and a decrease in nonclassical monocytes in patients with low disease activity or remission (DAS28-CRP < 3.2). Pseudobulk analysis by cell type identified 168 differentially expressed genes between RA and matched controls, with a downregulation of proinflammatory genes in the γδ T cell subset, alteration of genes associated with RA predisposition in the IFN-activated subset, and nonclassical monocytes. Additionally, we identified a gene signature associated with moderate-high disease activity, characterized by upregulation of proinflammatory genes such as TNF, JUN, EGR1, IFIT2, MAFB, and G0S2 and downregulation of genes including HLA-DQB1, HLA-DRB5, and TNFSF13B. Notably, cell-cell communication analysis revealed an upregulation of signaling pathways, including VISTA, in both moderate-high and remission-low disease activity contexts. Our findings provide valuable insights into the systemic cellular and molecular mechanisms underlying RA disease activity.

Authors

Marie Binvignat, Brenda Y. Miao, Camilla Wibrand, Monica M. Yang, Dmitry Rychkov, Emily Flynn, Joanne Nititham, Whitney Tamaki, Umair Khan, Alexander Carvidi, Melissa Krueger, Erene Niemi, Yang Sun, Gabriela K. Fragiadakis, Jérémie Sellam, Encarnita Mariotti-Ferrandiz, David Klatzmann, Andrew J. Gross, Chun Jimmie Ye, Atul J. Butte, Lindsey A. Criswell, Mary C. Nakamura, Marina Sirota

NADPH oxidase in B cells and macrophages protects against murine lupus by regulation of TLR7

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Abstract

Loss of NADPH oxidase (NOX2) exacerbates systemic lupus erythematosus (SLE) in mice and humans, but the mechanisms underlying this effect remain unclear. To identify the cell lineages in which NOX2 deficiency drives SLE, we employed conditional KO and chimeric approaches to delete Cybb in several hematopoietic cell lineages of MRL.Faslpr SLE-prone mice. Deletion of Cybb in macrophages/monocytes exacerbated SLE nephritis, though not to the degree observed in the Cybb global KOs. Unexpectedly, the absence of Cybb in B cells resulted in profound glomerulonephritis and interstitial nephritis, rivaling that seen with global deletion. Furthermore, we identified that NOX2 is a key regulator of TLR7, a driver of SLE pathology, both globally and specifically in B cells. This is mediated in part through suppression of TLR7-mediated NF-κB signaling in B cells. Thus, NOX2’s immunomodulatory effect in SLE is orchestrated not only by its function in the myeloid compartment, but through a pivotal role in B cells by selectively inhibiting TLR7 signaling.

Authors

Rachael A. Gordon, Haylee A. Cosgrove, Anthony Marinov, Sebastien Gingras, Jeremy S. Tilstra, Allison M. Campbell, Sheldon I. Bastacky, Michael Kashgarian, Andras Perl, Kevin M. Nickerson, Mark J. Shlomchik

Explainable deep learning and biomechanical modeling for TMJ disorder morphological risk factors

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Abstract

Clarifying multifactorial musculoskeletal disorder etiologies supports risk analysis, development of targeted prevention, and treatment modalities. Deep learning enables comprehensive risk factor identification through systematic analyses of disease data sets 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 participant-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 data sets by providing the crucial biomechanical context.

Authors

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

IL-27/Blimp-1 axis regulates the differentiation and function of Tim-3⁺ Tregs during early pregnancy

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Abstract

Decidual regulatory T cells (Tregs) are essential for successful pregnancy outcome. A subset of Tregs, T cell immunoglobulin and mucin domain-containing protein 3–positive regulatory T cells (TregsTim-3+), plays a central role in the acceptance of the fetus during early stages of normal pregnancy. The molecular mechanism regulating the differentiation and function of TregsTim-3+ is unknown. Here, we investigated the role of the transcription factor B lymphocyte-induced maturation protein 1 (Blimp-1) on decidual TregTim-3+ differentiation. We demonstrated that Blimp-1 enhanced the coexpression of negative costimulatory molecules (Tim-3, T cell immunoreceptor with Ig and ITIM domains, and programmed cell death protein 1) on Tregs and improved their immunosuppressive functions, including increased IL-10 secretion, suppression of effector T cell proliferation, and promotion of macrophage polarization toward the M2 phenotype. Furthermore, we showed that IL-27 regulated the expression of Tim-3 and Blimp-1 through the STAT1 signaling pathway and that transfer of TregsBlimp-1+ into an abortion-prone mouse model effectively reduced embryo absorption rate. We postulated that abnormalities in the IL-27/Blimp-1 axis might be associated with recurrent pregnancy loss (RPL). These findings provided insights for developing more efficient immunotherapies for women with RPL.

Authors

Si-Jia Zhao, Xiao-Hui Hu, Xin-Xiu Lin, Yu-Jing Zhang, Jing Wang, Huan Wang, Guang-Shun Gong, Gil Mor, Ai-Hua Liao

Transcriptome and microbiome-immune changes across preinvasive and invasive anal cancer lesions

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Abstract

Anal squamous cell carcinoma (ASCC) is a rare gastrointestinal malignancy linked to high-risk human papillomavirus (HPV) infection, which develops from precursor lesions like low-grade squamous intraepithelial lesions and high-grade squamous intraepithelial lesions (HGSILs). ASCC incidence varies across populations and poses increased risk for people living with HIV. Our investigation focused on transcriptomic and metatranscriptomic changes from squamous intraepithelial lesions to ASCC. Metatranscriptomic analysis highlighted specific bacterial species (e.g., Fusobacterium nucleatum, Bacteroides fragilis) more prevalent in ASCC than precancerous lesions. These species correlated with gene-encoding enzymes (Acca, glyQ, eno, pgk, por) and oncoproteins (FadA, dnaK), presenting potential diagnostic or treatment markers. Unsupervised transcriptomic analysis identified distinct sample clusters reflecting histological diagnosis, immune infiltrate, HIV/HPV status, and pathway activities, recapitulating anal cancer progression’s natural history. Our study unveiled molecular mechanisms in anal cancer progression, aiding in stratifying HGSIL cases based on low or high risk of progression to malignancy.

Authors

Ezequiel Lacunza, Valeria Fink, María E. Salas, Ana M. Gun, Jorge A. Basiletti, María A. Picconi, Mariano Golubicki, Juan Robbio, Mirta Kujaruk, Soledad Iseas, Sion Williams, María I. Figueroa, Omar Coso, Pedro Cahn, Juan C. Ramos, Martín C. Abba

Human-specific elimination of epithelial Siglec-XII suppresses the risk of inflammation-driven colorectal cancers

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Abstract

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 (encoding Siglec-XII) in epithelial transformation and cancer. Exogenous expression of the protein in cell lines and genetically engineered mice recapitulated approximately 30% of the human population in whom the protein is expressed in a form that cannot bind ligand because of a fixed, homozygous, human-universal missense mutation. Siglec-XII–null cells/mice recapitulated the remaining approximately 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 data sets, 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 favorable prognosis. They revealed a hitherto-unknown evolutionary genetic mechanism for an ethnic/environmental predisposition of carcinogenesis.

Authors

Hector A. Cuello, Saptarshi Sinha, Andrea L. Verhagen, Nissi Varki, Ajit Varki, Pradipta Ghosh

Postprandial exercise regulates tissue-specific triglyceride uptake through angiopoietin-like proteins

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Abstract

Fuel substrate switching between carbohydrates and fat is essential for maintaining metabolic homeostasis. During aerobic exercise, the predominant energy source gradually shifts from carbohydrates to fat. While it is well known that exercise mobilizes fat storage from adipose tissues, it remains largely obscure how circulating lipids are distributed tissue-specifically according to distinct energy requirements. Here, we demonstrate that aerobic exercise is linked to nutrient availability to regulate tissue-specific activities of lipoprotein lipase (LPL), the key enzyme catabolizing circulating triglyceride (TG) for tissue uptake, through the differential actions of angiopoietin-like (ANGPTL) proteins. Exercise reduced the tissue binding of ANGPTL3 protein, increasing LPL activity and TG uptake in the heart and skeletal muscle in the postprandial state specifically. Mechanistically, exercise suppressed insulin secretion, attenuating hepatic Angptl8 transcription through the PI3K/mTOR/CEBPα pathway, which is imperative for the tissue binding of its partner ANGPTL3. Constitutive expression of ANGPTL8 hampered lipid utilization and resulted in cardiac dysfunction in response to exercise. Conversely, exercise promoted the expression of ANGPTL4 in white adipose tissues, overriding the regulatory actions of ANGPTL8/ANGPTL3 in suppressing adipose LPL activity, thereby diverting circulating TG away from storage. Collectively, our findings show an overlooked bifurcated ANGPTL-LPL network that orchestrates fuel switching in response to aerobic exercise.

Authors

Xiaomin Liu, Yiliang Zhang, Bingqian Han, Lin Li, Ying Li, Yifan Ma, Shijia Kang, Quan Li, Lingkai Kong, Kun Huang, Bao-liang Song, Yong Liu, Yan Wang

Childhood obesity’s effect on cognition and brain connectivity worsens with low family income

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Childhood obesity and its adverse health consequences have risen worldwide, with low socioeconomic status increasing the risk in high-income countries like the United States. Understanding the interplay between childhood obesity, cognition, socioeconomic factors, and the brain is crucial for prevention and treatment. Using data from the Adolescent Brain Cognitive Development (ABCD) study, we investigated how body mass index (BMI) relates to brain structural and functional connectivity metrics. Children with obesity or who are overweight (n = 2,356) were more likely to live in poverty and exhibited lower cognitive performance compared with children with a healthy weight (n = 4,754). Higher BMI was associated with multiple brain measures that were strongest for lower longitudinal diffusivity in corpus callosum; increased activity in cerebellum, insula, and somatomotor cortex; and decreased functional connectivity in multimodal brain areas, with effects more pronounced among children from low-income families. Notably, nearly 80% of the association of low income and 70% of the association of impaired cognition on BMI were mediated by higher brain activity in somatomotor areas. Increased resting activity in somatomotor areas and decreased structural and functional connectivity likely contribute to the higher risk of being overweight or having obesity among children from low-income families. Supporting low-income families and implementing educational interventions to improve cognition may promote healthy brain function and reduce the risk of obesity.

Authors

Dardo Tomasi, Nora D. Volkow

The proteasome subunit psmb1 is essential for craniofacial cartilage maturation and morphogenesis

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Abstract

Craniofacial dysmorphisms are among the most common birth defects. Proteasome mutations frequently result in craniofacial dysmorphisms, including lower jaw malformations; however, the underlying mechanisms are unknown. Here, we used a zebrafish proteasome subunit β 1 (psmb1) mutant to define the cellular mechanisms underlying proteasome mutation-induced craniofacial dysmorphisms. psmb1 mutants exhibited a flattened ceratohyal and smaller Meckel’s and palatoquadrate cartilages. Ceratohyal flattening was a result of failed chondrocyte convergent extension, accompanied by reduced numbers of chondrocytes in the lower jaw due to defects in chondrocyte differentiation. Morphogenesis of craniofacial muscles and tendons was similarly perturbed. psmb1 mutants lacked the hyohyal muscles, and craniofacial tendons were shortened and disorganized. We additionally identified a critical period for proteasome function in craniofacial development, specifically during chondrocyte and muscle differentiation. psmb1 overexpression in sox10+ cells of mutant embryos rescued both cartilage and tendon phenotypes but induced only a partial rescue of the muscle phenotype, indicating that psmb1 was required in both tissue-autonomous and nonautonomous fashions during craniofacial development. Overall, our work demonstrates that psmb1 is required for craniofacial cartilage, tendon, and muscle differentiation and morphogenesis.

Authors

Bess M. Miller, Wolfram Goessling

Sclerostin antibody corrects periodontal disease in type 2 diabetic mice

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Abstract

Type 2 diabetes (T2D) is on the rise worldwide and is associated with various complications in the oral cavity. Using an adult-onset diabetes preclinical model, we demonstrated profound periodontal alterations in T2D mice, including inflamed gingiva, disintegrated periodontal ligaments (PDLs), 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 4 weeks, starting 4 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.

Authors

Hakan Turkkahraman, Shannan Flanagan, Tianli Zhu, Nisreen Akel, Silvia Marino, Dayane Ortega-Gonzalez, Xue Yuan, Teresita Bellido

Vedolizumab and ART in recent HIV-1 infection unveil the role of α4β7 in reservoir size

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Abstract

BACKGROUND We evaluated the safety and viral rebound, after analytical treatment interruption (ATI), of vedolizumab and ART in recent HIV-1 infection. We used this model to analyze the effect of α4β7 on the HIV-1 reservoir size.METHODS Participants started ART with monthly vedolizumab infusions, and ATI was performed at week 24. Biopsies were obtained from ileum and cecum at baseline and week 24. Vedolizumab levels, HIV-1 reservoir, flow cytometry, and cell-sorting and antibody competition experiments were assayed.RESULTS Vedolizumab was safe and well tolerated. No participant achieved undetectable viremia off ART 24 weeks after ATI. Only a modest effect on the time to achieve more than 1,000 HIV-1 RNA copies/mL and the proportion of participants off ART was observed, being higher in the vedolizumab group compared with historical controls. Just before ATI, α4β7 expression was associated with HIV-1 DNA and RNA in peripheral blood and with PD1 and TIGIT levels. Importantly, a complete blocking of α4β7 was observed on peripheral CD4+ T cells but not in gut (ileum and cecum), where α4β7 blockade and vedolizumab levels were inversely associated with HIV-1 DNA.CONCLUSION Our findings support α4β7 as an important determinant in HIV-1 reservoir size, suggesting the complete α4β7 blockade in tissue as a promising tool for HIV-cure combination strategies.TRIAL REGISTRATION ClinicalTrials.gov NCT03577782.FUNDING This work was supported by the Instituto de Salud Carlos III (Fondo Europeo de Desarrollo Regional, “a way to make Europe,” research contracts FI17/00186 and FI19/00083 and research projects PI18/01532, PI19/01127, PI22/01796), Conserjería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía (research projects P20/00906), the Red Temática de Investigación Cooperativa en SIDA (RD16/0025/0020), and the Spanish National Research Council.

Authors

Maria Reyes Jimenez-Leon, Carmen Gasca-Capote, Cristina Roca-Oporto, Nuria Espinosa, Salvador Sobrino, Maria Fontillon-Alberdi, Ce Gao, Isabelle Roseto, Gregory Gladkov, Inmaculada Rivas-Jeremias, Karin Neukam, Jose German Sanchez-Hernandez, Raul Rigo-Bonnin, Antonio J. Cervera-Barajas, Rosario Mesones, Federico García, Ana Isabel Alvarez-Rios, Sara Bachiller, Joana Vitalle, Alberto Perez-Gomez, María Inés Camacho-Sojo, Isabel Gallego, Christian Brander, Ian McGowan, Beatriz Mothe, Pompeyo Viciana, Xu Yu, Mathias Lichterfeld, Luis F. Lopez-Cortes, Ezequiel Ruiz-Mateos

PI3Kγ promotes neutrophil extracellular trap formation by noncanonical pyroptosis in abdominal aortic aneurysm

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Abstract

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 a crucial trigger of AAA, and identifying upstream regulatory targets is thus key to discovering therapeutic agents for AAA. We revealed that phosphoinositide-3-kinase γ (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 cyclic AMP/protein kinase A 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.

Authors

Yacheng Xiong, Shuai Liu, Yu Liu, Jiani Zhao, Jinjian Sun, Yongqing Li, Baihong Pan, Wei Wang