Treg activation during allograft tolerance induction requires mitochondrial-induced TGFβ1 in type 1 conventional dendritic cells

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Abstract

The role of type 1 conventional dendritic cells (cDC1) in tolerance induction to solid organ allografts is unknown and important for strategies that seek to prolong allograft viability. Using a murine model deficient in cDC1s, we report cDC1s are required for donor antigen and costimulation blockade (DST + CoB) tolerance induction and survival of cardiac allografts. cDC1 deficiency led to decreases in CD4+CD25+FoxP3+ T cells within both allograft and spleen tissue of transplant recipients and this was found to be antigen specific. Donor antigen stimulation induced TGF-β1 expression both in vivo cDC1 and in vitro Flt3L derived cDC1. Genetic deletion of Tgfβ1 in cDC1s prevented induction of antigen specific CD4+CD25+FoxP3+ T cells and was associated with cardiac allograft rejection. In parallel, single-cell RNA sequencing and metabolic analysis revealed upregulation of cDC1 mitochondrial metabolic signatures after in vivo exposure to DST + CoB. Genetic inactivation of cDC1 mitochondrial metabolism reduced expression of cDC1 TGF-β1, decreased antigen specific T regulatory cell populations, and impaired allograft tolerance. Taken together, our findings newly implicate cDC1s in strategies to preserve solid organ allografts and also implicate mitochondrial metabolism of cDC1s as a molecular mechanism to enhance the generation of antigen-specific CD4+CD25+FoxP3+ T cells through TGF-β1.

Authors

Samantha L Schroth, Lei Zhang, Rebecca T.L. Jones, Kristofor Glinton, Nikita L. Mani, Hiroyasu Inui, Jesse T. Davidson, Samuel E. Weinberg, Navdeep Chandel, Maria-Luisa Alegre, Edward B. Thorp

Gut-specific histamine 3 receptor signaling orchestrates microglia-dependent resolution of peripheral inflammation

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Abstract

Chronic inflammatory diseases, like rheumatoid arthritis (RA) have been described to cause central nervous system (CNS) activation. Less is known about environmental factors that enable the CNS to suppress peripheral inflammation in RA. Here, we identified gut microbiota-derived histamine as such factor. We show that low levels of histamine activate the enteric nervous system, increase inhibitory neurotransmitter concentrations in the spinal cord and restore homeostatic microglia, thereby reducing inflammation in the joints. Selective histamine 3 receptor (H3R) signaling in the intestine is critical for this effect, as systemic and intrathecal application did not show effects. Microglia depletion or pharmacological silencing of local nerve fibers impaired oral H3R agonist-induced pro-resolving effects on arthritis. Moreover, therapeutic supplementation of the short-chain fatty acid (SCFA) propionate identified one way to expand local intestinal histamine concentrations in mice and humans. Thus, we define a gut-CNS-joint axis pathway where microbiota-derived histamine initiates the resolution of arthritis via the CNS.

Authors

Kerstin Dürholz, Leona Ehnes, Mathias Linnerbauer, Eva Schmid, Heike Danzer, Michael Hinzpeter-Schmidt, Lena Lößlein, Lena Amend, Michael Frech, Vugar Azizov, Fabian Schälter, Arne Gessner, Sébastien Lucas, Till-Robin Lesker, R. Verena Taudte, Jörg Hofmann, Felix Beyer, Hadar Bootz-Maoz, Yasmin Reich, Hadar Romano, Daniele Mauro, Ruth Beckervordersandforth, Maja Skov Kragsnaes, Torkell Ellingsen, Wei Xiang, Aiden Haghikia, Cezmi A. Akdis, Francesco Ciccia, Tobias Bäuerle, Kerstin Sarter, Till Strowig, Nissan Yissachar, Georg Schett, Veit Rothhammer, Mario M. Zaiss

Combinatorial therapy regimens targeting preclinical models of melanoma resistant to immune checkpoint blockade

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Abstract

Few effective therapeutic options exist following progression on immune checkpoint blockade (ICB) for melanoma. Here we utilize a platform incorporating transcriptomic profiling, high-throughput drug screening (HTDS) and murine models to demonstrate the pre-clinical efficacy of several combinatorial regimens against ICB-resistant melanoma. Transcriptomic analysis of ICB-resistant melanomas demonstrated activation of several targetable pathways. HTDS targeting these pathways identified several effective combinations in ICB-resistant patient-derived xenograft models. The combination of cobimetinib and regorafenib (termed Cobi+Reg) emerged as a particularly promising regimen, with efficacy against distinct molecular melanoma subtypes and following progression on ICB in immunocompetent models. Transcriptomic and spatial analysis of Cobi+Reg-treated tumors demonstrated upregulation of antigen presentation machinery, with concomitantly increased activated T cell infiltration. Combining Cobi+Reg with ICB was superior to either modality in vivo. This analytical platform exploits the biology of ICB-resistant melanoma to identify therapeutic vulnerabilities, resulting in the identification of drug combinations that form the basis for rational clinical trial design in the setting of advanced melanoma resistant to ICB.

Authors

Imran Khan, Aida Rodriguez-Brotons, Anukana Bhattacharjee, Vladimir Bezrookove, Altaf Dar, David De Semir, Mehdi Nosrati, Ryan Ice, Liliana Soroceanu, Stanley P. Leong, Kevin B. Kim, Yihui Shi, James E. Cleaver, James R. Miller, Pierre-Yves Desprez, John M. Kirkwood, Marcus Bosenberg, Nathan Salomonis, Sean McAllister, Mohammed Kashani-Sabet

Somatic mutations in TBX3 promote hepatic clonal expansion by accelerating VLDL secretion

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Abstract

Somatic mutations that increase clone fitness or resist disease are positively selected, but the impact of these mutations on organismal health remains unclear. We previously showed that Tbx3 deletion increases hepatocyte fitness within fatty livers. Here, we detected TBX3 somatic mutations in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). In mice, Tbx3 deletion protected against, whereas Tbx3 overexpression exacerbated MASLD. Tbx3 deletion reduced lipid overload by accelerating VLDL secretion. Choline deficient diets, which block VLDL secretion, abrogated this protective effect. TBX3 transcriptionally suppressed the conventional secretory pathway and cholesterol biosynthesis. Hdlbp is a direct target of TBX3 that is responsible for the altered VLDL secretion. In contrast to wild-type TBX3, the TBX3 I155S and A280S mutations found in patients failed to suppress VLDL secretion. In conclusion, TBX3 mutant clones expand during MASLD through increased lipid disposal, demonstrating that clonal fitness can benefit the liver at the cost of hyperlipidemia.

Authors

Gregory Mannino, Gabriella Quinn, Min Zhu, Zixi Wang, Xun Wang, Boyuan Li, Meng-Hsiung Hsieh, Thomas Mathews, Lauren Zacharias, Wen Gu, Purva Gopal, Natalia Brzozowska, Peter Campbell, Matt Hoare, Glen Liszczak, Hao Zhu

NOTCH1 reverses immune suppression in small cell lung cancer through reactivation of STING

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Abstract

Downregulation of antigen presentation and lack of immune infiltration are defining features of small cell lung cancer (SCLC) limiting response to immune checkpoint blockade (ICB). While a high MHC Class I, immune-inflamed subset benefits from ICB, underlying mechanisms of immune response in SCLC have yet to be elucidated. Here we show that in the landmark IMpower133 clinical trial high, but not low, NOTCH1 expression is significantly associated with longer survival with the addition of ICB to chemotherapy among ~80% of SCLC patients with neuroendocrine-enriched tumors (ASCL1-enriched, HR 0.39, P = 0.0012; NEUROD1-enriched, HR 0.44, P = 0.024). Overexpression or pharmacologic activation of NOTCH1 in ASCL1 and NEUROD1 SCLC cell lines dramatically upregulates MHC Class I through epigenetic reactivation of STING. In syngeneic mouse models, Notch1 activation reprograms SCLC tumors from immune-excluded to immune-inflamed, facilitating durable, complete responses with ICB combined with a STING agonist. STING1 expression is significantly enriched in high compared to low NOTCH1 expressing tumors in IMpower133 thereby validating our proposed mechanism. Our data reveal a previously undiscovered role for NOTCH1 as a critical driver of SCLC immunogenicity and a potential predictive biomarker for ICB in SCLC. NOTCH1 activation may be a therapeutic strategy to unleash anti-tumor immune responses in SCLC and other neuroendocrine cancers in which NOTCH1 is typically suppressed.

Authors

Yoo Sun Kim, Barzin Y. Nabet, Briana N. Cortez, Nai-Yun Sun, Robin Sebastian, Christophe E. Redon, Anagh Ray, Liang Liu, Afeez A. Ishola, Sarah Loew, Anjali Dhall, Sivasish Sindiri, Velimir Gayevskiy, Min-Jung Lee, Shraddha Rastogi, Nahoko Sato, Noemi Kedei, Thorkell Andresson, Sudipto Das, Suresh Kumar, Alan E. Bers, Hongliang Zhang, Alberto Chiappori, Priyanka Gopal, Mohamed E. Abazeed, Haobin Chen, Mirit I. Aladjem, Yves Pommier, Moises J. Velez, David S. Shames, Nitin Roper

Caloric Restriction Promotes Resolution of Atherosclerosis in Obese Mice, while Weight Regain Accelerates its Progression

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Abstract

While weight loss is highly recommended for those with obesity, >60% will regain their lost weight. This weight cycling is associated with elevated risk of cardiovascular disease, relative to never having lost weight. How weight loss/regain directly influence atherosclerotic inflammation is unknown. Thus, we studied short-term caloric restriction (stCR) in obese hypercholesterolemic mice, without confounding effects from changes in diet composition. Weight loss was found to promote atherosclerosis resolution independent of plasma cholesterol. From single-cell RNA-sequencing and subsequent mechanistic studies, this can be partly attributed to a unique subset of macrophages accumulating with stCR in epididymal white adipose tissue (eWAT) and atherosclerotic plaques. These macrophages, distinguished by high expression of Fcgr4, help to clear necrotic cores in atherosclerotic plaques. Conversely, weight regain (WR) following stCR accelerated atherosclerosis progression with disappearance of Fcgr4+ macrophages from eWAT and plaques. Furthermore, WR caused reprogramming of immune progenitors, sustaining hyper-inflammatory responsiveness. In summary, we have developed a model to investigate the inflammatory effects of weight cycling on atherosclerosis and the interplay between adipose tissue, bone marrow, and plaques. The findings suggest potential approaches to promote atherosclerosis resolution in obesity and weight cycling through induction of Fcgr4+ macrophages and inhibition of immune progenitor reprogramming.

Authors

Bianca Scolaro, Franziska Krautter, Emily J. Brown, Aleepta Guha Ray, Rotem Kalev-Altman, Marie Petitjean, Sofie Delbare, Casey Donahoe, Stephanie Pena, Michela L. Garabedian, Cyrus A. Nikain, Maria Laskou, Ozlem Tufanli, Carmen Hannemann, Myriam Aouadi, Ada Weinstock, Edward A. Fisher

Type 1 Classical Dendritic Cells Govern Long-term Cardiac Allograft Acceptance

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Abstract

Authors

Macee C. Owen, Vinay R. Penna, Hao Dun, Wenjun Li, Benjamin J. Kopecky, Kenneth M. Murphy, Daniel Kreisel, Kory J. Lavine

ICOS regulates IL-10 production in group 2 innate lymphoid cells via cholesterol and cortisol biosynthesis

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Abstract

Group 2 innate lymphoid cells (ILC2s) play a crucial role in inducing type 2 inflammation in the lungs in response to allergens. Our study investigated the regulatory mechanism of IL-10 production by ILC2s and its impact on airway hyperreactivity (AHR), focusing on the role of ICOS. We found that inhibiting ICOS in pulmonary ILC2s significantly enhances IL-10 production. The absence of ICOS reprograms ILC2 steroid metabolism, leading to increased cholesterol and cortisol biosynthesis, and subsequent Glucocorticoid receptor (GR) activation. This reprogramming regulates MAF and NFIL3 activation, promoting IL-10 production. Notably, in vivo GR inhibition or ILC2-specific GR deficiency exacerbated AHR development in multiple mouse models. We extended these findings to human ILC2s, demonstrating concordant results between murine models and human cells. Our results indicate that ICOS negatively regulates IL-10 production in ILC2s by controlling cholesterol and cortisol biosynthesis. This mechanism provides new insights into the complex interplay between ILC2s, ICOS, and glucocorticoid signaling in the context of allergic airway inflammation.

Authors

Yoshihiro Sakano, Kei Sakano, Benjamin P. Hurrell, Mohammad H. Kazemi, Xin Li, Stephen Shen, Omid Akbari

SPNS1 variants cause multi-organ disease and implicate lysophospholipid transport as critical for mTOR-regulated lipid homeostasis

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Abstract

SPNS1 is a lysosomal transporter mediating the salvage of lysoglycerophospholipids, the degradative products of lysosomal phospholipid catabolism. However, a role of lysolipid transport and salvage in regulating cellular lipid homeostasis and in disease is lacking. Here, we identified two families with biallelic SPNS1 loss-of-function variants that presented primarily with progressive liver and striated muscle injury. Patient fibroblasts accumulated lysophospholipids including lysoplasmalogens and cholesterol in lysosomes with reduced cellular plasmalogens. Notably, SPNS1 deficiency resulted in reduced biogenesis of cytosolic lipid droplets containing triglycerides and cholesteryl esters. Mechanistically, we found that lysophospholipids transported by SPNS1 into the cytosol quantitatively contributed to triglyceride synthesis while lysosomal buildup of lyso-ether-phospholipid inhibited lysosomal cholesterol egress, effects that were enhanced with inhibition of mTOR. These findings support a gene-disease association and reveal connectivity between lysosomal transport of lysophospholipids and storage of reserve cellular energy as triglyceride and in the regulation of cholesterol homeostasis, processes that become important under nutrient limitation.

Authors

Menglan He, Mei Ding, Michaela Chocholouskova, Cheen Fei Chin, Martin Engvall, Helena Malmgren, Matias Wagner, Marlen C. Lauffer, Jacob Heisinger, May Christine V. Malicdan, Valérie Allamand, Madeleine Durbeej, Angelica M. Delgado-Vega, Thomas Sejersen, Ann Nordgren, Federico Torta, David L. Silver

Hyperactivated Interferon-gamma Pathways in Perianal Fistulizing Crohn’s Disease by Single-Cell and Spatial Multi-omics

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Abstract

Perianal fistulizing Crohn’s disease (PCD) is a common and debilitating complication with elusive pathophysiology. To define actionable immunologic targets in PCD, we recruited patients with PCD (n = 24), CD without perianal disease (NPCD, n = 10), and idiopathic/cryptoglandular perianal fistulas (IPF, n = 29). Biopsies from fistula tracts, fistula opening, and rectal mucosa were analyzed using single-cell RNA-sequencing (scRNA-seq), mass cytometry (CyTOF), and spatial transcriptomics (ST). Global hyperactivation of IFN-g pathways distinguished PCD from idiopathic perianal fistulas and CD without perianal disease in the fistula tracts and/or intestinal mucosa. IFN-g and TNF-a signaling directly induced genes involved in epithelial-to-mesenchymal transition in PCD rectal epithelial cells. Enhanced IFN-g signaling in PCD was driven by pathogenic Th17 (pTh17) cells, which were recruited and activated by myeloid cells overexpressing LPS signature (LPS_myeloid). pTh17 and LPS_myeloid cells co-localized adjacent to PCD fistula tracts on ST and drove local IFN-g signaling. Anti-TNFs facilitated fistula healing by downregulating T and myeloid cell signatures, while promoting mucosal barrier repair and immunoregulatory processes. Key single-cell findings were validated by bulk RNA-seq data of an independent CD cohort. To summarize, we identified IFN-g-driven mechanisms contributing to pathogenesis and highlighted its blockade as a therapeutic strategy for PCD.

Authors

Siyan Cao, Khai M. Nguyen, Kaiming Ma, Tingyi Tan, Xin Yao, Ta-Chiang Liu, Malek Ayoub, Jalpa Devi, Sami Samaan, Yizhou Liu, Radhika Smith, Matthew L. Silviera, Steven R. Hunt, Paul E. Wise, Matthew G. Mutch, Sean C. Glasgow, William C. Chapman Jr, Michelle L. Cowan, Mathew A. Ciorba, Marco Colonna, Parakkal Deepak