Korhonen et al. explore the mechanistic basis of Ang2 activity in lymphangiogenesis and report that Ang2/Tie/PI3K signaling is required for cell-surface expression of VEGFR3. The cover image shows overgrowth of dermal lymphatic vessels in a mouse model of oncogenic PI3K–driven lymphatic malformation, with immunofluorescent staining of VEGFR3 (purple), LYVE1 (lymphatic vessels, green), and PECAM-1 (blood vessels, gray). Image credit: Yan Zhang.
Vessel co-option has been demonstrated to mediate colorectal cancer liver metastasis (CRCLM) resistance to anti-angiogenic therapy. The current mechanisms underlying vessel co-option have mainly focused on the "hijacker" tumor cells, whereas the function of the “hijackee” sinusoidal blood vessels has not been explored. Here, we found that the occurrence of vessel co-option in bevacizumab-resistant CRCLM xenografts was associated with increased expression of fibroblast activation protein alpha (FAPα) in the co-opted hepatic stellate cells (HSCs), which was dramatically attenuated in HSC-specific conditional Fap-knockout mice bearing CRCLM allografts. Mechanistically, bevacizumab treatment induced hypoxia to upregulate the expression of fibroblast growth factor-binding protein 1 (FGFBP1) in tumor cells. Gain- or loss-of-function experiments revealed that the bevacizumab-resistant tumor cell-derived FGFBP1 induced FAPα expression by enhancing the paracrine FGF2-FGFR1-ERK1/2-EGR1 signaling pathway in HSCs. FAPα promoted CXCL5 secretion in HSCs, which activated CXCR2 to promote the epithelial-mesenchymal transition of tumor cells and the recruitment of myeloid-derived suppressor cells. These findings were further validated in CRCLM patient-derived tumor tissues. Targeting FAPα+ HSCs effectively disrupted the co-opted sinusoidal blood vessels and overcame bevacizumab resistance. Our study highlights the role of FAPα+ HSCs in vessel co-option and provides an effective strategy to overcome the vessel co-option-mediated bevacizumab resistance.
Ming Qi, Shuran Fan, Maohua Huang, Jinghua Pan, Yong Li, Qun Miao, Wenyu Lyu, Xiaobo Li, Lijuan Deng, Shenghui Qiu, Tongzheng Liu, Weiqing Deng, Xiaodong Chu, Chang Jiang, Wenzhuo He, Liangping Xia, Yunlong Yang, Jian Hong, Qi Qi, Wenqian Yin, Xiangning Liu, Changzheng Shi, Minfeng Chen, Wencai Ye, Dongmei Zhang
Accidental injury to the cardiac conduction system (CCS), a network of specialized cells embedded within the heart and indistinguishable from the surrounding heart muscle tissue, is a major complication in cardiac surgeries. Here, we addressed this unmet need by engineering targeted antibody-dye conjugates directed against CCS, allowing for the visualization of the CCS in vivo following a single intravenous injection in mice. These optical imaging tools showed high sensitivity, specificity, and resolution, with no adverse effects to CCS function. Further, with the goal of creating a viable prototype for human use, we generated a fully human monoclonal Fab, that similarly targets the CCS with high specificity. We demonstrate that, when conjugated to an alternative cargo, this Fab can also be used to modulate CCS biology in vivo providing a proof-of-principle for targeted cardiac therapeutics. Finally, in performing differential gene expression analyses of the entire murine CCS at single-cell resolution, we uncovered and validated a suite of additional cell surface markers that can be used to molecularly target the distinct subcomponents of the CCS, each prone to distinct life-threatening arrhythmias. These findings lay the foundation for translational approaches targeting the CCS for visualization and therapy in cardiothoracic surgery, cardiac imaging and arrhythmia management.
William R. Goodyer, Benjamin M. Beyersdorf, Lauren Duan, Nynke S. van den Berg, Sruthi Mantri, Francisco X. Galdos, Nazan Puluca, Jan W. Buikema, Soah Lee, Darren Salmi, Elise R. Robinson, Stephan Rogalla, Dillon P. Cogan, Chaitan Khosla, Eben L. Rosenthal, Sean M. Wu
To understand how kidney donation leads to excess preeclampsia risk, we studied pregnant outbred mice with prior uninephrectomy and compared them to sham-treated littermates carrying both kidneys. During pregnancy, uninephrectomized mice failed to achieve physiological increase of glomerular filtration rate, and during late gestation developed hypertension, albuminuria, glomerular endothelial damage, and excess placental production of soluble fms-like tyrosine kinase 1 (sFLT1), an anti-angiogenic protein implicated in the pathogenesis of preeclampsia. Maternal hypertension in uninephrectomized mice was associated with low plasma volumes, increased rate of fetal resorption, impaired spiral artery remodeling and placental ischemia. To evaluate potential mechanisms, we studied plasma metabolite changes using mass spectrometry and noted that L-kynurenine, a metabolite of L-tryptophan, was upregulated ~3 fold during pregnancy when compared to pre-pregnant concentrations in the same animals, consistent with prior reports suggesting a protective role for L-kynurenine in placental health. However, uninephrectomized mice failed to upregulate L-kynurenine during pregnancy; furthermore, when uninephrectomized mice were fed L-kynurenine in drinking water throughout pregnancy, their preeclampsia-like state was rescued, including reversal of placental ischemia and normalization of sFLT1 levels. In aggregate, we provide a mechanistic basis for how impaired renal reserve and resulting failure to upregulate L-kynurenine during pregnancy can lead to impaired placentation, placental hypoperfusion, anti-angiogenic state and subsequent preeclampsia.
Vincent Dupont, Anders H. Berg, Michifumi Yamashita, Chengqun Huang, Ambart E. Covarrubias, Shafat Ali, Aleksandr Stotland, Jennifer E. Van Eyk, Belinda Jim, Ravi Thadhani, S. Ananth Karumanchi
NVX-CoV2373 is an adjuvanted recombinant full-length SARS-CoV-2 spike trimer protein vaccine demonstrated to be protective against COVID-19 in efficacy trials. Here we demonstrate that vaccinated subjects made CD4+ T cell responses after one and two doses of NVX-CoV2373, and a subset of individuals made CD8+ T cell responses. Characterization of the vaccine-elicited CD8+ T cells demonstrated IFN𝛾 production. Characterization of the vaccine-elicited CD4+ T cells revealed both circulating T follicular helper cells (cTFH) and TH1 cells (IFN𝛾, TNFa, and IL-2) were detectable within 7 days of the primary immunization. Spike-specific CD4+ T cells were correlated with the magnitude of the later SARS-CoV-2 neutralizing antibody titers, indicating that robust generation of CD4+ T cells, capable of supporting humoral immune responses, may be a key characteristic of NVX-CoV2373 which utilizes Matrix-M™ adjuvant.
Carolyn Rydyznski Moderbacher, Christina J. Kim, Jose Mateus, Joyce S. Plested, Mingzhu Zhu, Shane Cloney-Clark, Daniela Weiskopf, Alessandro Sette, Louis Fries, Gregory Glenn, Shane Crotty
Infantile (fetal and neonatal) megakaryocytes have a distinct phenotype consisting of hyperproliferation, limited morphogenesis, and low platelet production capacity. These properties contribute to clinical problems that include thrombocytopenia in neonates, delayed platelet engraftment in recipients of cord blood stem cell transplants, and inefficient ex vivo platelet production from pluripotent stem cell-derived megakaryocytes. The infantile phenotype results from deficiency of the actin-regulated coactivator, MKL1, which programs cytoskeletal changes driving morphogenesis. As a strategy to complement this molecular defect, we screened pathways with potential to affect MKL1 function and found that Dyrk1a kinase inhibition dramatically enhanced megakaryocyte morphogenesis in vitro and in vivo. Dyrk1 inhibitors rescued enlargement, polyploidization, and thrombopoiesis in human neonatal megakaryocytes. Megakaryocytes derived from induced pluripotent stem cells responded in a similar manner. Progenitors undergoing Dyrk1 inhibition demonstrated filamentous actin assembly, MKL1 nuclear translocation, and modulation of MKL1 target genes. Loss of function studies confirmed MKL1 involvement in this morphogenetic pathway. Ablim2, a stabilizer of filamentous actin, increased with Dyrk1 inhibition, and Ablim2 knockdown abrogated the actin, MKL1, and morphogenetic responses to Dyrk1 inhibition. These results thus delineate a pharmacologically tractable morphogenetic pathway whose manipulation may alleviate clinical problems associated with the limited thrombopoietic capacity of infantile megakaryocytes.
Kamaleldin E. Elagib, Ashton Brock, Cara M. Clementelli, Gohar Mosoyan, Lorrie L. Delehanty, Ranjit K. Sahu, Alexandra Pacheco-Benichou, Corinne Fruit, Thierry Besson, Stephan W. Morris, Koji Eto, Chintan Jobaliya, Deborah L. French, Paul Gadue, Sandeep Singh, Xinrui Shi, Fujun Qin, Robert Cornelison, Hui Li, Camelia Iancu-Rubin, Adam N. Goldfarb
JCI This Month is a digest of the research, reviews, and other features published each month.
Aging plays a central role in many chronic diseases affecting all systems of the body. Nine hallmarks of aging have been identified: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. This new review series on Aging closely examines how these hallmarks contribute to the initiation and progression of disease. Curated by series editor Dr. James Kirkland, topics span aging’s role in immune system function, cancer, cognitive decline and neurodegenerative disease, and metabolism. The reviews also discuss the latest developments in senotherapeutic strategies that destroy senescent cells, reverse senescence, or target specific aging hallmarks with a critical eye.