Abstract
The neonatal mouse kidney retains nephron progenitor cells in a nephrogenic zone for 3 days after birth. We evaluated whether de novo nephrogenesis can be induced postnatally beyond 3 days. Given the long-term implications of nephron number for kidney health, it would be useful to enhance nephrogenesis in the neonate. We induced nephron reduction by cryoinjury with or without contralateral nephrectomy during the neonatal period or after 1 week of age. There was no detectable compensatory de novo nephrogenesis, as determined by glomerular counting and lineage tracing. Contralateral nephrectomy resulted in additional adaptive healing, with little or no fibrosis, but did not also stimulate de novo nephrogenesis. In contrast, injury initiated at 1 week of age led to healing with fibrosis. Thus, despite the presence of progenitor cells and ongoing nephron maturation in the newborn mouse kidney, de novo nephrogenesis is not inducible by acute nephron reduction. This indicates that additional nephron progenitors cannot be recruited after birth despite partial renal ablation providing a reparative stimulus and suggests that nephron number in the mouse is predetermined at birth.
Authors
Florian Tögel, M. Todd Valerius, Benjamin S. Freedman, Rossella Latrino, Mor Grinstein, Joseph V. Bonventre
Abstract
HIV-1–specific broadly neutralizing antibodies (bnAbs) typically develop in individuals with continuous high-level viral replication and increased immune activation, conditions that cannot be reproduced during prophylactic immunization. Understanding mechanisms supporting bnAb development in the absence of high-level viremia may be important for designing bnAb-inducing immunogens. Here, we show that the breadth of neutralizing antibody responses in HIV-1 controllers was associated with a relative enrichment of circulating CXCR5+CXCR3+PD-1lo CD4+ T cells. These CXCR3+PD-1lo Tfh-like cells were preferentially induced in vitro by functionally superior dendritic cells from controller neutralizers, and able to secrete IL-21 and support B cells. In addition, these CXCR3+PD-1lo Tfh-like cells contained higher proportions of stem cell–like memory T cells, and upon antigenic stimulation differentiated into PD-1hi Tfh-like cells in a Notch-dependent manner. Together, these data suggest that CXCR5+CXCR3+PD-1lo cells represent a dendritic cell–primed precursor cell population for PD-1hi Tfh-like cells that may contribute to the generation of bnAbs in the absence of high-level viremia.
Authors
Enrique Martin-Gayo, Jacqueline Cronin, Taylor Hickman, Zhengyu Ouyang, Madelene Lindqvist, Kellie E. Kolb, Julian Schulze zur Wiesch, Rafael Cubas, Filippos Porichis, Alex K. Shalek, Jan van Lunzen, Elias K. Haddad, Bruce D. Walker, Daniel E. Kaufmann, Mathias Lichterfeld, Xu G. Yu
Abstract
Vascular abnormalities are a common component of eye diseases that often lead to vision loss. Vaso-obliteration is associated with inherited retinal degenerations, since photoreceptor atrophy lowers local metabolic demands and vascular support to those regions is no longer required. Given the degree of neurovascular crosstalk in the retina, it may be possible to use one cell type to rescue another cell type in the face of severe stress, such as hypoxia or genetically encoded cell-specific degenerations. Here, we show that intravitreally injected human endothelial colony-forming cells (ECFCs) that can be isolated and differentiated from cord blood in xeno-free media collect in the vitreous cavity and rescue vaso-obliteration and neurodegeneration in animal models of retinal disease. Furthermore, we determined that a subset of the ECFCs was more effective at anatomically and functionally preventing retinopathy; these cells expressed high levels of CD44, the hyaluronic acid receptor, and IGFBPs (insulin-like growth factor–binding proteins). Injection of cultured media from ECFCs or only recombinant human IGFBPs also rescued the ischemia phenotype. These results help us to understand the mechanism of ECFC-based therapies for ischemic insults and retinal neurodegenerative diseases.
Authors
Susumu Sakimoto, Valentina Marchetti, Edith Aguilar, Kelsey Lee, Yoshihiko Usui, Salome Murinello, Felicitas Bucher, Jennifer K. Trombley, Regis Fallon, Ravenska Wagey, Carrie Peters, Elizabeth L. Scheppke, Peter D. Westenskow, Martin Friedlander
Abstract
Amphetamine (AMPH) or methamphetamine (METH) abuse can cause oxidative damage and is a risk factor for diseases including pulmonary arterial hypertension (PAH). Pulmonary artery endothelial cells (PAECs) from AMPH-associated-PAH patients show DNA damage as judged by γH2AX foci and DNA comet tails. We therefore hypothesized that AMPH induces DNA damage and vascular pathology by interfering with normal adaptation to an environmental perturbation causing oxidative stress. Consistent with this, we found that AMPH alone does not cause DNA damage in normoxic PAECs, but greatly amplifies DNA damage in hypoxic PAECs. The mechanism involves AMPH activation of protein phosphatase 2A, which potentiates inhibition of Akt. This increases sirtuin 1, causing deacetylation and degradation of HIF1α, thereby impairing its transcriptional activity, resulting in a reduction in pyruvate dehydrogenase kinase 1 and impaired cytochrome
Authors
Pin-I Chen, Aiqin Cao, Kazuya Miyagawa, Nancy F. Tojais, Jan K. Hennigs, Caiyun G. Li, Nathaly M. Sweeney, Audrey S. Inglis, Lingli Wang, Dan Li, Matthew Ye, Brian J. Feldman, Marlene Rabinovitch
Abstract
A SNP identified as rs548234, which is found in
Authors
Su Hwa Jang, Helen Chen, Peter K. Gregersen, Betty Diamond, Sun Jung Kim
Abstract
Peroxisome proliferator–activated receptor–δ (PPARD) is upregulated in many major human cancers, but the role that its expression in cancer cells has in metastasis remains poorly understood. Here, we show that specific PPARD downregulation or genetic deletion of PPARD in cancer cells significantly repressed metastasis in various cancer models in vivo. Mechanistically, PPARD promoted angiogenesis via interleukin 8 in vivo and in vitro. Analysis of transcriptome profiling of HCT116 colon cancer cells with or without genetic deletion of PPARD and gene expression patterns in The Cancer Genome Atlas colorectal adenocarcinoma database identified novel pro-metastatic genes (GJA1, VIM, SPARC, STC1, SNCG) as PPARD targets. PPARD expression in cancer cells drastically affected epithelial-mesenchymal transition, migration, and invasion, further underscoring its necessity for metastasis. Clinically, high PPARD expression in various major human cancers (e.g., colorectal, lung, breast) was associated with significantly reduced metastasis-free survival. Our results demonstrate that PPARD, a druggable protein, is an important molecular target in metastatic cancer.
Authors
Xiangsheng Zuo, Weiguo Xu, Min Xu, Rui Tian, Micheline J. Moussalli, Fei Mao, Xiaofeng Zheng, Jing Wang, Jeffrey S. Morris, Mihai Gagea, Cathy Eng, Scott Kopetz, Dipen M. Maru, Asif Rashid, Russell Broaddus, Daoyan Wei, Mien-Chie Hung, Anil K. Sood, Imad Shureiqi
Abstract
Oxidation of calmodulin-dependent protein kinase II (ox-CaMKII) by ROS has been associated with asthma. However, the contribution of ox-CaMKII to the development of asthma remains to be fully characterized. Here, we tested the effect of ox-CaMKII on IgE-mediated mast cell activation in an allergen-induced mouse model of asthma using oxidant-resistant CaMKII MMVVδ knockin (MMVVδ) mice. Compared with WT mice, the allergen-challenged MMVVδ mice displayed less airway hyperresponsiveness (AHR) and inflammation. These MMVVδ mice exhibited reduced levels of ROS and diminished recruitment of mast cells to the lungs. OVA-activated bone marrow–derived mast cells (BMMCs) from MMVVδ mice showed a significant inhibition of ROS and ox-CaMKII expression. ROS generation was dependent on intracellular Ca2+ concentration in BMMCs. Importantly, OVA-activated MMVVδ BMMCs had suppressed degranulation, histamine release, leukotriene C4, and IL-13 expression. Adoptive transfer of WT, but not MMVVδ, BMMCs, reversed the alleviated AHR and inflammation in allergen-challenged MMVVδ mice. The CaMKII inhibitor KN-93 significantly suppressed IgE-mediated mast cell activation and asthma. These studies support a critical but previously unrecognized role of ox-CaMKII in mast cells that promotes asthma and suggest that therapies to reduce ox-CaMKII may be a novel approach for asthma.
Authors
Jingjing Qu, Danh C. Do, Yufeng Zhou, Elizabeth Luczak, Wayne Mitzner, Mark E. Anderson, Peisong Gao
Abstract
Osteoarthritis is the most common form of arthritis, and pain relief with opioid-like drugs is a commonly used therapeutic for osteoarthritic patients. Recent studies published by our group showed that the kappa opioid receptor (KOR) is highly expressed during human development in joint-forming cells. However, the precise role of this receptor in the skeletal system remains elusive. The main aim of the current study was to investigate the role of KOR signaling in synovial and cartilaginous tissues in pathological conditions. Our data demonstrate that KOR null mice exhibit accelerated cartilage degeneration after injury when compared with WT mice. Activation of KOR signaling increased the expression of anabolic enzymes and inhibited cartilage catabolism and degeneration in response to proinflammatory cytokines such as TNF-α. In addition, selective KOR agonists increased joint lubrication via the activation of cAMP/CREB signaling in chondrocytes and synovial cells. Taken together, these results demonstrate direct effects of KOR agonists on cartilage and synovial cells and reveals a protective effect of KOR signaling against cartilage degeneration after injury. In addition to pain control, local administration of dynorphin or other KOR agonist represents an attractive therapeutic approach in patients with early stages of osteoarthritis.
Authors
Ling Wu, Shu Zhang, Ruzanna Shkhyan, Siyoung Lee, Francesca Gullo, Claire D. Eliasberg, Frank A. Petrigliano, Kai Ba, Jing Wang, Yunfeng Lin, Denis Evseenko
Abstract
In patients with sickle cell disease (SCD), the polymerization of intraerythrocytic hemoglobin S promotes downstream vaso-occlusive events in the microvasculature. While vaso-occlusion is known to occur in the lung, often in the context of systemic vaso-occlusive crisis and the acute chest syndrome, the pathophysiological mechanisms that incite lung injury are unknown. We used intravital microscopy of the lung in transgenic humanized SCD mice to monitor acute vaso-occlusive events following an acute dose of systemic lipopolysaccharide sufficient to trigger events in SCD but not control mice. We observed cellular microembolism of precapillary pulmonary arteriolar bottlenecks by neutrophil-platelet aggregates. Blood from SCD patients was next studied under flow in an in vitro microfluidic system. Similar to the pulmonary circulation, circulating platelets nucleated around arrested neutrophils, translating to a greater number and duration of neutrophil-platelet interactions compared with normal human blood. Inhibition of platelet P-selectin with function-blocking antibody attenuated the neutrophil-platelet interactions in SCD patient blood in vitro and resolved pulmonary arteriole microembolism in SCD mice in vivo. These results establish the relevance of neutrophil-platelet aggregate formation in lung arterioles in promoting lung vaso-occlusion in SCD and highlight the therapeutic potential of targeting platelet adhesion molecules to prevent acute chest syndrome.
Authors
Margaret F. Bennewitz, Maritza A. Jimenez, Ravi Vats, Egemen Tutuncuoglu, Jude Jonassaint, Gregory J. Kato, Mark T. Gladwin, Prithu Sundd
Abstract
Mechanical complications of myocardial infarction (MI) are often fatal. Little is known about endogenous factors that predispose to myocardial rupture after MI. Ectonucleoside triphosphate diphosphohydrolase (CD39) could be a critical mediator of propensity to myocardial rupture after MI due to its role in modulating inflammation and thrombosis. Using a model of permanent coronary artery ligation, rupture was virtually abrogated in
Authors
Nadia R. Sutton, Takanori Hayasaki, Matthew C. Hyman, Anuli C. Anyanwu, Hui Liao, Danica Petrovic-Djergovic, Linda Badri, Amy E. Baek, Natalie Walker, Keigo Fukase, Yogendra Kanthi, Scott H. Visovatti, Ellen L. Horste, Jessica J. Ray, Sascha N. Goonewardena, David J. Pinsky
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