Zheng, et al. identify metabolic biomarkers in the circulation that accurately diagnose fumarate hydratase–deficient renal cell carcinoma, the most aggressive form of kidney cancer. These succinate-modified metabolites are produced via a unique enzymatic cascade that is initiated in response to the high concentration of fumarate in these tumors. Image credit: Liang Zheng and Kirsteen Liu.
Sepsis remains a leading cause of human death and currently has no pathogenesis-specific therapy. Hampered progress is partly due to a lack of insight into deep mechanistic processes. In the last decade, deciphering the functions of small non-coding microRNAs (miRNAs) in sepsis pathogenesis became a dynamic research topic. To screen for new miRNA targets for sepsis therapeutics, we used human samples for miRNA array from peripheral blood mononuclear cells from sepsis patients and controls, blood samples from two cohorts of sepsis patients, and multiple animal models: mouse cecum ligation-puncture (CLP)-induced sepsis, mouse viral miRNA challenge, and baboon Gram-positive and Gram-negative sepsis models. miR-93-5p met the criteria for a therapeutic target, being overexpressed in baboons that died early after induction of sepsis, downregulated in humans who survived after sepsis, and correlated with negative clinical prognosticators for sepsis. Therapeutically, inhibiting miR-93-5p prolonged the overall survival of mice with CLP-induced sepsis, with a stronger effect in older mice. Mechanistically, anti-miR-93-5p therapy reduced inflammatory monocytes and increased circulating effector memory T cells, especially the CD4+ subset. AGO2-immunoprecipitation in miR-93-knockout T cells identified important regulatory receptors, such as CD28, as direct miR-93-5p target genes. In conclusion, miR-93-5p is a potential therapeutic target in sepsis through regulating both innate and adaptive immunity with possibly more benefit for the elderly than the young patients.
Mihnea P. Dragomir, Enrique Fuentes-Mattei, Melanie Winkle, Keishi Okubo, Recep Bayraktar, Erik Knutsen, Aiham Qdaisat, Meng Chen, Yongfeng Li, Masayoshi Shimizu, Lan Pang, Kevin Liu, Xiuping Liu, Simone Anfossi, Huanyu Zhang, Ines Koch, Anh M. Tran, Swati Mohapatra, Anh Ton, Mecit Kaplan, Matthew W. Anderson, Spencer J. Rothfuss, Robert Silasi, Ravi S. Keshari, Manuela Ferracin, Cristina Ivan, Cristian Rodriguez-Aguayo, Gabriel Lopez-Berestein, Constantin Georgescu, Pinaki P. Banerjee, Rafet Basar, Ziyi Li, David Horst, Catalin Vasilescu, Maria Teresa S. Bertilaccio, Katayoun Rezvani, Florea Lupu, Sai-Ching Yeung, George A. Calin
Neutrophil (PMN) mobilization to sites of insult is critical for host defense and requires transendothelial migration (TEM). TEM involves several well-studied sequential adhesive interactions with vascular endothelial cells (ECs); however, what initiates or terminates this process is not well-understood. Here we describe what we believe to be a new mechanism where vessel associated macrophages (VAMs) through localized interactions primed EC responses to form ICAM-1 “hot spots”, to support PMN TEM. Using real-time intravital microscopy (IVM) on lipopolysaccharide (LPS)-inflamed intestines in CX3CR1-EGFP macrophage-reporter mice, complemented by whole-mount tissue imaging and flow cytometry, we found that macrophage vessel association is critical for the initiation of PMN-EC adhesive interactions, PMN TEM and subsequent accumulation in the intestinal mucosa. Anti-colony stimulating factor 1 receptor (CSF1R) antibody-mediated macrophage depletion in the lamina propria and at the vessel wall resulted in elimination of ICAM-1 hot spots impeding PMN-EC interactions and TEM. Mechanistically, the use of human clinical specimens, TNFα knockout macrophage chimeras, TNFα/TNF receptor (TNFR) neutralization and multi-cellular macrophage-EC-PMN cocultures revealed that macrophage-derived TNFα and EC TNFR2 axis mediated this regulatory mechanism and was required for PMN TEM. As such, our findings identified clinically relevant mechanism by which macrophages regulate PMN trafficking in inflamed mucosa.
Xingsheng Ren, Laura D. Manzanares, Enzo B. Piccolo, Jessica M. Urbanczyk, David P. Sullivan, Lenore K. Yalom, Triet M. Bui, Connor Lantz, Hinda Najem, Parambir S. Dulai, Amy B. Heimberger, Edward B. Thorp, Ronen Sumagin
Although glucose is the basic fuel essential to maintain the viability and functions of all cells, some neurons, namely glucose-inhibited (GI) neurons, paradoxically increase their firing activities when glucose falls and are inhibited by high glucose. The ionic mechanisms mediating electric responses of GI neurons to glucose fluctuations remain unclear. Here we showed that currents mediated by anoctamin 4 (Ano4) channel are only detected in GI neurons in the ventromedial hypothalamic nucleus (VMH) and are functionally required for their activation in response to low glucose. Genetic disruption of the Ano4 gene in VMH neurons reduced blood glucose and impaired counterregulatory responses during hypoglycemia in mice. Activation of VMHAno4 neurons increased food intake and blood glucose, while chronic inhibition of VMHAno4 neurons ameliorated hyperglycemia in a type 1 diabetic mouse model. Finally, we showed that VMHAno4 neurons represent a unique orexigenic VMH population and transmit a positive valence, while stimulation of non-Ano4 neurons in the VMH suppress feeding and transmit a negative valence. Together, our results indicate that the Ano4 channel and VMHAno4 neurons are potential therapeutic targets for human diseases with abnormal feeding behavior or glucose imbalance.
Longlong Tu, Jonathan C. Bean, Yang He, Hailan Liu, Meng Yu, Hesong Liu, Nan Zhang, Na Yin, Junying Han, Nikolas Anthony Scarcelli, Kristine Marie Conde, Mengjie Wang, Yongxiang Li, Bing Feng, Peiyu Gao, Zhao-Lin Cai, Makoto Fukuda, Mingshan Xue, Qingchun Tong, Yongjie Yang, Lan Liao, Jianming Xu, Chunmei Wang, Yanlin He, Yong Xu
Epigenetic status-altering mutations in chromatin-modifying enzymes are a feature of human diseases including many cancers. However, the functional outcomes and cellular dependencies arising from these mutations remain unresolved. In this study, we investigated cellular dependencies, or vulnerabilities, that arise when enhancer function is compromised by loss of the frequently mutated COMPASS family members MLL3 and MLL4. CRISPR dropout screens in MLL3/4-depleted mouse embryonic stem cells (mESCs) revealed synthetic lethality upon suppression of purine and pyrimidine nucleotide synthesis pathways. Consistently, we observed a shift in metabolic activity towards increased purine synthesis in MLL3/4 knockout (KO) mESCs. These cells also exhibited enhanced sensitivity to the purine synthesis inhibitor lometrexol, which induced a unique gene expression signature. RNA sequencing identified the top MLL3/4 target genes coinciding with suppression of purine metabolism, and tandem mass tag (TMT) proteomic profiling further confirmed upregulation of purine synthesis in MLL3/4 KO cells. Mechanistically, compensation by MLL1/COMPASS underlied these effects. Finally, we demonstrated that tumors with MLL3 and/or MLL4 mutations were highly sensitive to lometrexol in vivo, both in culture and in animal models of cancer. Our results depicted a targetable metabolic dependency arising from epigenetic factor deficiency, providing molecular insight to inform therapy for cancers with epigenetic alterations secondary to MLL3/4 COMPASS dysfunction.
Zibo Zhao, Kaixiang Cao, Jun Watanabe, Cassandra N. Philips, Jacob M. Zeidner, Yukitomo Ishi, Qixuan Wang, Sarah R. Gold, Katherine Junkins, Elizabeth T. Bartom, Feng Yue, Navdeep S. Chandel, Rintaro Hashizume, Issam Ben-Sahra, Ali Shilatifard
Bulk analysis of renal allograft biopsies (rBx) identified RNA transcripts associated with acute cellular rejection (ACR); however, these lacked cellular context critical to mechanistic understanding of how rejection occurs despite immunosuppression (IS). We performed combined single cell RNA transcriptomic and TCRα/β sequencing on rBx from patients with ACR under differing IS: tacrolimus, iscalimab, and belatacept. We found distinct CD8+ T cell phenotypes (e.g., effector, memory, exhausted) depending upon IS type, particularly within clonally expanded cells (CD8EXP). Gene expression of CD8EXP identified therapeutic targets that were influenced by IS type. TCR analysis revealed a highly restricted number of CD8EXP, independent of HLA mismatch or IS type. Subcloning of TCRα/β cDNAs from CD8EXP into Jurkat76 cells (TCR–/–) conferred alloreactivity by mixed lymphocyte reaction. Analysis of sequential rBx samples revealed persistence of CD8EXP that decreased, but were not eliminated, after successful anti-rejection therapy. In contrast, CD8EXP were maintained in treatment-refractory rejection. Finally, most rBx-derived CD8EXP were also observed in matching urine samples, providing precedent for using urine-derived CD8EXP as a surrogate for those found in the rejecting allograft. Overall, our data define the clonal CD8+ T cell response to ACR, paving the next steps to improve detection, assessment, and treatment of rejection.
Tiffany Shi, Ashley R. Burg, J. Timothy Caldwell, Krishna M. Roskin, Cyd M. Castro-Rojas, P. Chukwunalu Chukwuma, George I. Gray, Sara G. Foote, Jesus A. Alonso, Carla M. Cuda, David A. Allman, James S. Rush, Catherine H. Regnier, Grazyna Wieczorek, Rita R. Alloway, Adele R. Shields, Brian M. Baker, E. Steve Woodle, David A. Hildeman
JCI This Month is a digest of the research, reviews, and other features published each month.
Glioblastomas are high-grade and aggressive CNS tumors. Due to heterogeneous composition, rapid growth, and suppressive immune microenvironment, gliomablastomas remain difficult to successfully treat. JCI editors Amy Heimberger, Daniel Brat, and Maciej Lesniak curated the reviews in this issue’s series to confront the many aspects of immune involvement in these clinically challenging tumors. Reviews in this series describe how tumor-associated macrophages, microglia, and neutrophils modulate glioblastoma progression and therapy response. They also explore new concepts for targeting the immune microenvironment in glioblastoma, including strategies targeting immunometabolism or epigenetic regulation, personalized immunotherapy approaches, and next-generation antigen presenting cell-based therapies.