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Abstract
Selective and controlled expansion of endogenous β-cells has been pursued as a potential therapy for diabetes. Ideally, such therapies would preserve feedback control of β-cell proliferation to avoid excessive β-cell expansion. Here, we identified a regulator of β-cell proliferation whose inactivation results in controlled β-cell expansion: the protein deacetylase Sirtuin 2 (SIRT2). Sirt2 deletion in β-cells of mice increased β-cell proliferation during hyperglycemia with little effect in homeostatic conditions, indicating preservation of feedback control of β-cell mass. SIRT2 restrains proliferation of human islet β-cells, demonstrating conserved SIRT2 function. Analysis of acetylated proteins in islets treated with a SIRT2 inhibitor revealed that SIRT2 deacetylates enzymes involved in oxidative phosphorylation, dampening the adaptive increase in oxygen consumption during hyperglycemia. At the transcriptomic level, Sirt2 inactivation has context-dependent effects on β-cells, with Sirt2 controlling how β-cells interpret hyperglycemia as a stress. Finally, we provide proof-of-principle that systemic administration of a GLP1-coupled Sirt2-targeting antisense oligonucleotide achieves β-cell Sirt2 inactivation and stimulates β-cell proliferation during hyperglycemia. Overall, these studies identify a therapeutic strategy for increasing β-cell mass in diabetes without circumventing feedback control of β-cell proliferation. Future work should test the extent that these findings translate to human β-cells from individuals with and without diabetes.
Authors
Matthew Wortham, Bastian Ramms, Chun Zeng, Jacqueline R. Benthuysen, Somesh Sai, Dennis P. Pollow, Fenfen Liu, Michael Schlichting, Austin R. Harrington, Bradley Liu, Thazha P. Prakash, Elaine C. Pirie, Han Zhu, Siyouneh Baghdasarian, Sean T. Lee, Victor A. Ruthig, Kristen L. Wells, Johan Auwerx, Orian S. Shirihai, Maike Sander
Abstract
Authors
Alyssa M. Duffy, Anshika Goenka, Maryam I. Azeem, Azmain Taz, Sayalee V. Potdar, Sara A. Scott, Ellen Marin, Jonathan L. Kaufman, Craig C. Hofmeister, Nisha S. Joseph, Vikas A. Gupta, Sagar Lonial, Ajay K. Nooka, Madhav V. Dhodapkar, Kavita M. Dhodapkar
Elevated NR2F1 underlies the persistence of invasive disease after treatment of BRAF-mutant melanoma
Abstract
Despite the clinical success of targeted inhibitors in cutaneous melanoma, therapeutic responses are transient and influenced by the aged tumor microenvironment, and drug-tolerant residual cells seed resistance. Given the similarities between drug tolerance and cellular dormancy, we studied the dormancy marker, nuclear receptor subfamily 2 group F member 1 (NR2F1), in response to targeted therapy. We utilized BRAF-V600E inhibitors (BRAFi) plus MEK inhibitors (MEKi) in BRAF-mutant melanoma models since melanoma patients treated with this combination display minimal residual disease, but ultimately tumors relapse. Transcriptomic analysis of melanoma samples from patients treated up to 20 days with BRAFi + MEKi showed increased expression of NR2F1. Similarly, NR2F1 was highly expressed in the drug-tolerant invasive cell state of minimal residual disease in patient-derived and mouse-derived xenograft tumors on BRAFi + MEKi treatment. Overexpression of NR2F1 alone was sufficient to reduce BRAFi + MEKi effects on tumor growth in vivo as well as on cell proliferation, death, and invasion in vitro. NR2F1-overexpressing cells were enriched for hallmarks gene sets for mTORC1 signaling, and NR2F1 bound to the promoter regions of genes involved in mTORC1 signaling. These cells were sensitive to the combination of BRAFi, MEKi plus rapamycin in vitro and in vivo. Melanomas from aged mice, which are known to exhibit a decreased response to BRAFi + MEKi, displayed higher levels of NR2F1 compared to tumors from young mice. Depleting NR2F1 levels in an aged mouse melanoma model improved the response to targeted therapy. These findings show high NR2F1 expression in ‘invasive-state’ residual cells and that targeting NR2F1-high cells with mTORC1 inhibitors could improve outcomes in melanoma patients.
Authors
Manoela Tiago, Timothy J. Purwin, Casey D. Stefanski, Renaira Silva, Mitchell E. Fane, Yash Chhabra, Jelan I. Haj, Jessica L.F. Teh, Rama Kadamb, Weijia Cai, Sheera R. Rosenbaum, Vivian Chua, Nir Hacohen, Michael A. Davies, Jessie Villanueva, Inna Chervoneva, Ashani T. Weeraratna, Dan A. Erkes, Claudia Capparelli, Julio A. Aguirre-Ghiso, Andrew E. Aplin
Abstract
The fetal liver is the primary site of hematopoietic stem cell (HSC) generation during embryonic development. However, the molecular mechanisms governing the transition of hematopoiesis from the fetal liver to the bone marrow (BM) remain incompletely understood. Here, we identify the mammalian Polycomb group (PcG) protein Yin Yang 1 (YY1) as a key regulator of this developmental transition. Conditional deletion of Yy1 in the hematopoietic system during fetal development results in neonatal lethality and depletion of the fetal HSC pool. YY1-deficient fetal HSCs exhibit impaired migration and fail to engraft in the adult BM, thereby losing their ability to reconstitute hematopoiesis. Transcriptomic analysis reveals that Yy1 knockout disrupts genetic networks controlling cell motility and adhesion in fetal hematopoietic stem and progenitor cells (HSPCs). Notably, YY1 does not directly bind the promoters of most dysregulated genes. Instead, it modulates chromatin accessibility at regulatory loci, orchestrating broader epigenetic programs essential for HSPC migration and adhesion. Together, these findings establish YY1 as a critical epigenetic regulator of fetal HSC function and provide a mechanistic framework to further decipher how temporal epigenomic configurations determine HSC fetal-to-adult transition during development.
Authors
Sahitya Saka, Zhanping Lu, Yinghua Wang, Peng Liu, Deependra K. Singh, Junki P. Lee, Carmen G. Palii, Tyler R. Alvarez, Anna L. F. V. Assumpção, Xiaona You, Jing Zhang, Marjorie Brand, Michael L. Atchison, Xuan Pan
Abstract
Authors
Elena Godoy-Molina, Natalia L. Serrano, Aquilina Jiménez-González, Miquel Villaronga, Rosa M. Marqués Pérez-Bryan, Rubén Varela-Fernández, Stephanie Lotz-Esquivel, Alba Hevia Tuñón, Prachi P. Trivedi, Nina Horn, Joseph F. Standing, Víctor Mangas-Sanjuan, Mercè Capdevila, Aurora Mateos, Denis Broun, Svetlana Lutsenko, Ines Medina-Rivera, Rafael Artuch, Cristina Jou, Mònica Roldán, Pedro Arango-Sancho, Mónica Saez-Villafañe, Juan J. Ortiz-de-Urbina, Angela Pieras-López, Marta Duero, Rosa Farré, Jordi Pijuan, Janet Hoenicka, James C. Sacchettini, Michael J. Petris, Vishal M. Gohil, Francesc Palau
Abstract
Antiretroviral therapy (ART) prevents HIV-1 replication but does not eliminate the latent reservoir, the source of viral rebound if treatment is stopped. Autologous neutralizing antibodies (aNAbs) can block in vitro outgrowth of a subset of reservoir viruses and therefore potentially affect viral rebound upon ART interruption. We investigated aNAbs in 31 people with HIV-1 (PWH) on ART. Participants fell into two groups based on a high or low fraction of aNAb-resistant reservoir isolates, with most isolates being aNAb-resistant (IC50 >100 μg/ml). Time on uninterrupted ART was associated with higher aNAb resistance. However, pharmacodynamic analysis predicted that many isolates would be partially inhibited at physiologic IgG concentrations, to the same degree as by single antiretroviral drugs. Steep dose-response curve slopes, an indication of cooperativity, were observed for the rare isolates that were very strongly inhibited (>5 logs) by aNAbs. Resistance to aNAbs was not fully explained by declining in aNAb titers and may be driven partially by ADCC-mediated elimination of infected cells carrying aNAb-sensitive viruses over long time intervals, leaving only aNAb-resistant viruses which can contribute to viral rebound.
Authors
Natalie F. McMyn, Joseph Varriale, Hanna W. S. Wu, Vivek Hariharan, Milica Moskovljevic, Toong Seng Tan, Jun Lai, Anushka Singhal, Kenneth Lynn, Karam Mounzer, Pablo Tebas, Luis J. Montaner, Rebecca Hoh, Xu G. Yu, Mathias Lichterfeld, Francesco R. Simonetti, Colin Kovacs, Steven G. Deeks, Janet M. Siliciano, Robert F. Siliciano
Abstract
Background: Anti-TNF biologics are widely used to treat patients with immune-mediated inflammatory diseases. In mouse models, the complete absence of TNF impairs germinal center (GC) responses. Less is known about the impact of anti-TNF therapy on specific immune responses in humans. Widespread vaccination against SARS-CoV-2 offered an unprecedented opportunity to investigate the effects of biological therapies on responses to specific immunization. Previous work demonstrated that inflammatory bowel disease (IBD) patients treated with anti-TNF biologics exhibit decreased Spike-specific antibody responses compared to IBD patients treated with anti-IL-12/23 or healthy controls, even after four doses of mRNA vaccine. Methods: Here we analyzed humoral responses to SARS-CoV-2 immunization using single-cell RNA-Sequencing and flow cytometry of Spike-specific memory B cells (MBC), as well as avidity measurements of plasma antibodies from IBD patients treated with anti-TNF or anti-IL-12/23 or from healthy controls. Results: We observed decreased somatic hypermutation in the B cell receptors of Spike-specific MBCs and decreased antigen-specific MBC accumulation following SARS-CoV-2 mRNA vaccination in anti-TNF treated IBD patients, compared to IBD patients treated with anti-IL-12/23 or healthy controls. This decreased somatic hypermutation in Spike-specific MBCs in anti-TNF treated patients correlated with decreased and delayed antibody affinity maturation and reduced neutralization activity. Conclusion: These data provide in vivo evidence that anti-TNF, but not anti-IL-12/23, therapy impairs the quantity and quality of antigen-specific GC outputs in humans. Funding: Juan and Stefania Speck (donation) and by Canadian Institutes of Health Research (CIHR)/COVID-Immunity Task Force (CITF) grants VR-1 172711, VS1-175545, GA2-177716, GA1-177703 and CIHR FDN 143301 &143350.
Authors
Michelle W. Cheung, Samantha Xu, Janna R. Shapiro, Freda Qi, Melanie Delgado-Brand, Karen Colwill, Roya Dayam, Ying Liu, Jenny Choi, Joanne M. Stempak, James M. Rini, Vinod Chandran, Mark S. Silverberg, Anne-Claude Gingras, Tania H. Watts
Abstract
BACKGROUND. Endocrine therapy (ET) with tamoxifen (TAM) or aromatase inhibitors (AI) is highly effective against hormone receptor (HR) positive early breast cancer (BC), but resistance remains a major challenge. The primary objectives of our study were to understand the underlying mechanisms of primary resistance and to identify potential biomarkers. METHODS. We selected >800 patients in three sub-cohorts (Discovery, N=364, matched pairs), Validation 1, N=270, Validation 2, N= 176) of the West German Study Group (WSG) Adjuvant Dynamic marker-Adjusted Personalized Therapy (ADAPT) trial who underwent short-term pre-operative TAM or AI treatment. Treatment response was assessed by immunohistochemical labeling of proliferating cells with Ki67 before and after ET. We performed comprehensive molecular profiling, including targeted next-generation sequencing (NGS) and DNA methylation analysis using EPIC arrays, on post-treatment tumor samples. RESULTS.TP53 mutations were strongly associated with primary resistance to both TAM and AI. In addition, we identified distinct DNA methylation patterns in resistant tumors, suggesting alterations in key signaling pathways and tumor microenvironment composition. Based on these findings and patient age, we developed the Predictive Endocrine ResistanCe Index (PERCI). PERCI accurately stratified responders and non-responders in both treatment groups in all three sub-cohorts and predicted progression-free survival in an external validation cohort and in the combined sub-cohorts. CONCLUSION. Our results highlight the potential of PERCI to guide personalized endocrine therapy and improve patient outcomes. TRIAL REGISTRATION. WSG-ADAPT, ClinicalTrials.gov NCT01779206, Registered 2013-01-25, retrospectively registered.
Authors
Guokun Zhang, Vindi Jurinovic, Stephan Bartels, Matthias Christgen, Henriette Christgen, Leonie Donata Kandt, Lidiya Mishieva, Hua Ni, Mieke Raap, Janin Klein, Anna-Lena Katzke, Winfried Hofmann, Doris Steinemann, Ronald E. Kates, Oleg Gluz, Monika Graeser, Sherko Kuemmel, Ulrike Nitz, Christoph Plass, Ulrich Lehmann, Christine zu Eulenburg, Ulrich Mansmann, Clarissa Gerhauser, Nadia Harbeck, Hans H. Kreipe
Abstract
Acute ischemic organ diseases such as acute myocardial infarction and acute kidney injury often result in irreversible tissue damage and progress to chronic heart failure (CHF) and chronic kidney disease (CKD), respectively. However, the molecular mechanisms underlying the development of CHF and CKD remain incompletely understood. Here, we show that mice deficient in CD300a, an inhibitory immunoreceptor expressed on myeloid cells, showed enhanced efferocytosis by tissue-resident macrophages and decreased damage-associated molecular patterns and pathogenic SiglecFhi neutrophils, resulting in milder inflammation-associated tissue injury than wild-type mice after ischemia and reperfusion (IR). Notably, we uncovered that CD300a-deficiency on SiglecFlo neutrophils increased the signal transducer and activator of transcription 3-mediated production of pro-angiogenic and anti-fibrotic factors, resulting in milder adverse remodeling after IR. Our results demonstrated that CD300a plays an important role in the pathogenesis of ischemic tissue injury and adverse remodeling in the heart and kidney.
Authors
Nanako Nishiyama, Hitoshi Koizumi, Chigusa Nakahashi-Oda, Satoshi Fujiyama, Xuewei Ng, Hanbin Lee, Fumie Abe, Jinao Li, Yan Xu, Takehito Sugasawa, Kazuko Tajiri, Taketaro Sadahiro, Masaki Ieda, Keiji Tabuchi, Kazuko Shibuya, Akira Shibuya
Abstract
We recently described the evolution of a community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) USA300 variant responsible for an outbreak of skin and soft tissue infections. Acquisition of a mosaic version of the Φ11 prophage (mΦ11) that increases skin abscess size was an early step in CA-MRSA adaptation that primed the successful spread of the clone. The present report shows how prophage mΦ11 exerts its effect on virulence for skin infection without encoding a known toxin or fitness genes. Abscess size and skin inflammation were associated with DNA methylase activity of an mΦ11-encoded adenine methyltransferase (designated pamA). pamA increased expression of fibronectin-binding protein A (fnbA; FnBPA), and inactivation of fnbA eliminated the effect of pamA on abscess virulence without affecting strains lacking pamA. Thus, fnbA is a pamA-specific virulence factor. Mechanistically, pamA was shown to promote biofilm formation in vivo in skin abscesses, a phenotype linked to FnBPA’s role in biofilm formation. Collectively, these data reveal a critical mechanism—epigenetic regulation of staphylococcal gene expression—by which phage can regulate virulence to drive adaptive leaps by S. aureus.
Authors
Robert J. Ulrich, Magdalena Podkowik, Rebecca Tierce, Irnov Irnov, Gregory Putzel, Nora M. Samhadaneh, Keenan A. Lacey, Daiane Boff, Sabrina M. Morales, Sohei Makita, Theodora K. Karagounis, Erin E Zwack, Chunyi Zhou, Randie H. Kim, Karl Drlica, Alejandro Pironti, Harm van Bakel, Victor J. Torres, Bo Shopsin
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ISSN: 0021-9738 (print), 1558-8238 (online)