Dickkopf1 (DKK1) is a secretory protein that antagonizes oncogenic Wnt signaling by binding to the Wnt coreceptor low-density lipoprotein receptor–related protein 6 (LRP6). DKK1 may also regulate its own signaling to promote cancer cell proliferation, but the mechanism is not understood. Here, we identified cytoskeleton-associated protein 4 (CKAP4) as a DKK1 receptor and evaluated CKAP4-mediated DKK1 signaling in cancer cell proliferation. We determined that DKK1 binds CKAP4 and LRP6 with similar affinity but interacts with these 2 receptors with different cysteine-rich domains. DKK1 induced internalization of CKAP4 in a clathrin-dependent manner, further supporting CKAP4 as a receptor for DKK1. DKK1/CKAP4 signaling activated AKT by forming a complex between the proline-rich domain of CKAP4 and the Src homology 3 domain of PI3K, resulting in proliferation of normal cells and cancer cells. Expression of DKK1 and CKAP4 was frequent in tumor lesions of human pancreatic and lung cancers, and simultaneous expression of both proteins in patient tumors was negatively correlated with prognosis and relapse-free survival. An anti-CKAP4 antibody blocked the binding of DKK1 to CKAP4, suppressed AKT activity in a human cancer cell line, and attenuated xenograft tumor formation in immunodeficient mice. Together, our results suggest that CKAP4 is a potential therapeutic target for cancers that express both DKK1 and CKAP4.
Hirokazu Kimura, Katsumi Fumoto, Kensaku Shojima, Satoshi Nojima, Yoshihito Osugi, Hideo Tomihara, Hidetoshi Eguchi, Yasushi Shintani, Hiroko Endo, Masahiro Inoue, Yuichiro Doki, Meinoshin Okumura, Eiichi Morii, Akira Kikuchi
In humans, genetic variation of sortilin-related receptor, L(DLR class) A repeats containing (
Vanessa Schmidt, Nadja Schulz, Xin Yan, Annette Schürmann, Stefan Kempa, Matthias Kern, Matthias Blüher, Matthew N. Poy, Gunilla Olivecrona, Thomas E. Willnow
In Wilson disease (WD), functional loss of ATPase copper-transporting β (ATP7B) impairs biliary copper excretion, leading to excessive copper accumulation in the liver and fulminant hepatitis. Current US Food and Drug Administration– and European Medicines Agency–approved pharmacological treatments usually fail to restore copper homeostasis in patients with WD who have progressed to acute liver failure, leaving liver transplantation as the only viable treatment option. Here, we investigated the therapeutic utility of methanobactin (MB), a peptide produced by
Josef Lichtmannegger, Christin Leitzinger, Ralf Wimmer, Sabine Schmitt, Sabine Schulz, Yaschar Kabiri, Carola Eberhagen, Tamara Rieder, Dirk Janik, Frauke Neff, Beate K. Straub, Peter Schirmacher, Alan A. DiSpirito, Nathan Bandow, Bipin S. Baral, Andrew Flatley, Elisabeth Kremmer, Gerald Denk, Florian P. Reiter, Simon Hohenester, Friedericke Eckardt-Schupp, Norbert A. Dencher, Jerzy Adamski, Vanessa Sauer, Christoph Niemietz, Hartmut H.J. Schmidt, Uta Merle, Daniel Nils Gotthardt, Guido Kroemer, Karl Heinz Weiss, Hans Zischka
Transplantation is the only cure for end-stage organ failure, but without immunosuppression, T cells rapidly reject allografts. While genetic disparities between donor and recipient are major determinants of the kinetics of transplant rejection, little is known about the contribution of environmental factors. Because colonized organs have worse transplant outcome than sterile organs, we tested the influence of host and donor microbiota on skin transplant rejection. Compared with untreated conventional mice, pretreatment of donors and recipients with broad-spectrum antibiotics (Abx) or use of germ-free (GF) donors and recipients resulted in prolonged survival of minor antigen–mismatched skin grafts. Increased graft survival correlated with reduced type I IFN signaling in antigen-presenting cells (APCs) and decreased priming of alloreactive T cells. Colonization of GF mice with fecal material from untreated conventional mice, but not from Abx-pretreated mice, enhanced the ability of APCs to prime alloreactive T cells and accelerated graft rejection, suggesting that alloimmunity is modulated by the composition of microbiota rather than the quantity of bacteria. Abx pretreatment of conventional mice also delayed rejection of major antigen–mismatched skin and MHC class II–mismatched cardiac allografts. This study demonstrates that Abx pretreatment prolongs graft survival, suggesting that targeting microbial constituents is a potential therapeutic strategy for enhancing graft acceptance.
Yuk Man Lei, Luqiu Chen, Ying Wang, Andrew T. Stefka, Luciana L. Molinero, Betty Theriault, Keston Aquino-Michaels, Ayelet S. Sivan, Cathryn R. Nagler, Thomas F. Gajewski, Anita S. Chong, Caroline Bartman, Maria-Luisa Alegre
In HIV-1–infected patients, increased numbers of circulating CD8+ T cells are linked to increased risk of morbidity and mortality. Here, we identified a bystander mechanism that promotes CD8 T cell activation and expansion in untreated HIV-1–infected patients. Compared with healthy controls, untreated HIV-1–infected patients have an increased population of proliferating, granzyme B+, CD8+ T cells in circulation. Vβ expression and deep sequencing of CDR3 revealed that in untreated HIV-1 infection, cycling memory CD8 T cells possess a broad T cell repertoire that reflects the repertoire of the resting population. This suggests that cycling is driven by bystander activation, rather than specific antigen exposure. Treatment of peripheral blood mononuclear cells with IL-15 induced a cycling, granzyme B+ phenotype in CD8+ T cells. Moreover, elevated IL-15 expression in the lymph nodes of untreated HIV-1–infected patients correlated with circulating CD8+ T cell counts and was normalized in these patients following antiretroviral therapy. Together, these results suggest that IL-15 drives bystander activation of CD8+ T cells, which predicts disease progression in untreated HIV-1–infected patients and suggests that elevated IL-15 may also drive CD8+ T cell expansion that is linked to increased morbidity and mortality in treated patients.
Souheil-Antoine Younes, Michael L. Freeman, Joseph C. Mudd, Carey L. Shive, Arnold Reynaldi, Soumya Panigrahi, Jacob D. Estes, Claire Deleage, Carissa Lucero, Jodi Anderson, Timothy W. Schacker, Miles P. Davenport, Joseph M. McCune, Peter W. Hunt, Sulggi A. Lee, Sergio Serrano-Villar, Robert L. Debernardo, Jeffrey M. Jacobson, David H. Canaday, Rafick-Pierre Sekaly, Benigno Rodriguez, Scott F. Sieg, Michael M. Lederman
Glioblastomas co-opt stem cell regulatory pathways to maintain brain tumor–initiating cells (BTICs), also known as cancer stem cells. NOTCH signaling has been a molecular target in BTICs, but NOTCH antagonists have demonstrated limited efficacy in clinical trials. Recombining binding protein suppressor of hairless (RBPJ) is considered a central transcriptional mediator of NOTCH activity. Here, we report that pharmacologic NOTCH inhibitors were less effective than targeting RBPJ in suppressing tumor growth. While NOTCH inhibitors decreased canonical NOTCH gene expression, RBPJ regulated a distinct profile of genes critical to BTIC stemness and cell cycle progression. RBPJ was preferentially expressed by BTICs and required for BTIC self-renewal and tumor growth. MYC, a key BTIC regulator, bound the
Qi Xie, Qiulian Wu, Leo Kim, Tyler E. Miller, Brian B. Liau, Stephen C. Mack, Kailin Yang, Daniel C. Factor, Xiaoguang Fang, Zhi Huang, Wenchao Zhou, Kareem Alazem, Xiuxing Wang, Bradley E. Bernstein, Shideng Bao, Jeremy N. Rich
The severe liver pathology of untreated Wilson disease (WD) is associated with massive copper overload caused by mutations in a liver-specific copper-transporting ATPase, ATP7B. While early, presymptomatic detection and chelation with conventional copper-binding molecules enables effective and life-saving treatment, liver transplantation is the sole option currently available for those with advanced disease. In this issue of the
Stephen G. Kaler
Targeting glioblastoma stem cells with γ-secretase inhibitors (GSIs) disrupts the Notch pathway and has shown some benefit in both pre-clinical models and in patients during phase I/II clinical trials. However, it is largely unknown why some glioblastoma (GBM) does not respond to GSI treatment. In this issue of the
The secretory protein Dickkopf-1 (DKK-1) is a known Wnt antagonist and has been shown to suppress tumorigenesis in some cancer cells; however, it is also upregulated in many types of cancer and associated with poor prognosis. Wnt-independent mechanisms by which DKK-1 promotes cancer cell proliferation are not well understood. In this issue of the
Dheeraj Bhavanasi, Kelsey F. Speer, Peter S. Klein
Increasing evidence indicates that microbes have a large influence on immune function. Previous studies have linked pathogenic microorganisms with decreased allograft tolerance and subsequent rejection. In this issue of the
Mandy L. Ford
Small-cell lung cancer (SCLC) is a highly aggressive subtype of lung cancer with limited treatment options. CD47 is a cell-surface molecule that promotes immune evasion by engaging signal-regulatory protein alpha (SIRPα), which serves as an inhibitory receptor on macrophages. Here, we found that CD47 is highly expressed on the surface of human SCLC cells; therefore, we investigated CD47-blocking immunotherapies as a potential approach for SCLC treatment. Disruption of the interaction of CD47 with SIRPα using anti-CD47 antibodies induced macrophage-mediated phagocytosis of human SCLC patient cells in culture. In a murine model, administration of CD47-blocking antibodies or targeted inactivation of the
Kipp Weiskopf, Nadine S. Jahchan, Peter J. Schnorr, Sandra Cristea, Aaron M. Ring, Roy L. Maute, Anne K. Volkmer, Jens-Peter Volkmer, Jie Liu, Jing Shan Lim, Dian Yang, Garrett Seitz, Thuyen Nguyen, Di Wu, Kevin Jude, Heather Guerston, Amira Barkal, Francesca Trapani, Julie George, John T. Poirier, Eric E. Gardner, Linde A. Miles, Elisa de Stanchina, Shane M. Lofgren, Hannes Vogel, Monte M. Winslow, Caroline Dive, Roman K. Thomas, Charles M. Rudin, Matt van de Rijn, Ravindra Majeti, K. Christopher Garcia, Irving L. Weissman, Julien Sage
Hyperactivation of the mTOR pathway impairs hematopoietic stem cell (HSC) functions and promotes leukemogenesis. mTORC1 and mTORC2 differentially control normal and leukemic stem cell functions. mTORC1 regulates p70 ribosomal protein S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E–binding (eIF4E-binding) protein 1 (4E-BP1), and mTORC2 modulates AKT activation. Given the extensive crosstalk that occurs between mTORC1 and mTORC2 signaling pathways, we assessed the role of the mTORC1 substrate S6K1 in the regulation of both normal HSC functions and in leukemogenesis driven by the mixed lineage leukemia (MLL) fusion oncogene MLL-AF9. We demonstrated that S6K1 deficiency impairs self-renewal of murine HSCs by reducing p21 expression. Loss of S6K1 also improved survival in mice transplanted with MLL-AF9–positive leukemic stem cells by modulating AKT and 4E-BP1 phosphorylation. Taken together, these results suggest that S6K1 acts through multiple targets of the mTOR pathway to promote self-renewal and leukemia progression. Given the recent interest in S6K1 as a potential therapeutic target in cancer, our results further support targeting this molecule as a potential strategy for treatment of myeloid malignancies.
Joydeep Ghosh, Michihiro Kobayashi, Baskar Ramdas, Anindya Chatterjee, Peilin Ma, Raghuveer Singh Mali, Nadia Carlesso, Yan Liu, David R. Plas, Rebecca J. Chan, Reuben Kapur
Although Notch signaling is deregulated in prostate cancer, the role of this pathway in disease development and progression is not fully understood. Here, we analyzed 2 human prostate cancer data sets and found that higher Notch signaling correlates with increased metastatic potential and worse disease survival rates. We used the
Oh-Joon Kwon, Li Zhang, Jianghua Wang, Qingtai Su, Qin Feng, Xiang H.F. Zhang, Sendurai A. Mani, Robia Paulter, Chad J. Creighton, Michael M. Ittmann, Li Xin
Interactions between the epidermis and the immune system govern epidermal tissue homeostasis. These epidermis-immune interactions are altered in the inflammatory disease psoriasis; however, the pathways that underlie this aberrant immune response are not well understood. Here, we determined that Ras-related C3 botulinum toxin substrate 1 (RAC1) is a key mediator of epidermal dysfunction. RAC1 activation was consistently elevated in psoriatic epidermis and primary psoriatic human keratinocytes (PHKCs) exposed to psoriasis-related stimuli, but not in skin from patients with basal or squamous cell carcinoma. Expression of a constitutively active form of RAC1 (RACV12) in mice resulted in the development of lesions similar to those of human psoriasis that required the presence of an intact immune system. RAC1V12-expressing mice and human psoriatic skin showed similar RAC1-dependent signaling as well as transcriptional overlap of differentially expressed epidermal and immune pathways. Coculture of PHKCs with immunocytes resulted in the upregulation of RAC1-dependent proinflammatory cytokines, an effect that was reproduced by overexpressing RAC1 in normal human keratinocytes. In keratinocytes, modulating RAC1 activity altered differentiation, proliferation, and inflammatory pathways, including STAT3, NFκB, and zinc finger protein 750 (ZNF750). Finally, RAC1 inhibition in xenografts composed of human PHKCs and immunocytes abolished psoriasiform hyperplasia and inflammation in vivo. These studies implicate RAC1 as a potential therapeutic target for psoriasis and as a key orchestrator of pathologic epidermis-immune interactions.
Mårten C.G. Winge, Bungo Ohyama, Clara N. Dey, Lisa M. Boxer, Wei Li, Nazanin Ehsani-Chimeh, Allison K. Truong, Diane Wu, April W. Armstrong, Teruhiko Makino, Matthew Davidson, Daniela Starcevic, Andreas Kislat, Ngon T. Nguyen, Takashi Hashimoto, Bernard Homey, Paul A. Khavari, Maria Bradley, Elizabeth A. Waterman, M. Peter Marinkovich
Programmed death ligand-1 (PD-L1) interaction with PD-1 induces T cell exhaustion and is a therapeutic target to enhance immune responses against cancer and chronic infections. In murine bone marrow transplant models, PD-L1 expression on host target tissues reduces the incidence of graft-versus-host disease (GVHD). PD-L1 is also expressed on T cells; however, it is unclear whether PD-L1 on this population influences immune function. Here, we examined the effects of PD-L1 modulation of T cell function in GVHD. In patients with severe GVHD, PD-L1 expression was increased on donor T cells. Compared with mice that received WT T cells, GVHD was reduced in animals that received T cells from
Asim Saha, Roddy S. O’Connor, Govindarajan Thangavelu, Scott B. Lovitch, Durga Bhavani Dandamudi, Caleph B. Wilson, Benjamin G. Vincent, Victor Tkachev, Jan M. Pawlicki, Scott N. Furlan, Leslie S. Kean, Kazutoshi Aoyama, Patricia A. Taylor, Angela Panoskaltsis-Mortari, Rocio Foncea, Parvathi Ranganathan, Steven M. Devine, Joel S. Burrill, Lili Guo, Catarina Sacristan, Nathaniel W. Snyder, Ian A. Blair, Michael C. Milone, Michael L. Dustin, James L. Riley, David A. Bernlohr, William J. Murphy, Brian T. Fife, David H. Munn, Jeffrey S. Miller, Jonathan S. Serody, Gordon J. Freeman, Arlene H. Sharpe, Laurence A. Turka, Bruce R. Blazar
Hypoxia occurs in many pathological conditions, including chronic inflammation and tumors, and is considered to be an inhibitor of T cell function. However, robust T cell responses occur at many hypoxic inflammatory sites, suggesting that functions of some subsets are stimulated under low oxygen conditions. Here, we investigated how hypoxic conditions influence human T cell functions and found that, in contrast to naive and central memory T cells (TN and TCM), hypoxia enhances the proliferation, viability, and cytotoxic action of effector memory T cells (TEM). Enhanced TEM expansion in hypoxia corresponded to high hypoxia-inducible factor 1α (HIF1α) expression and glycolytic activity compared with that observed in TN and TCM. We determined that the glycolytic enzyme GAPDH negatively regulates
Yang Xu, Arindam Chaudhury, Ming Zhang, Barbara Savoldo, Leonid S. Metelitsa, John Rodgers, Jason T. Yustein, Joel R. Neilson, Gianpietro Dotti
Renal preglomerular arterioles regulate vascular tone to ensure a large pressure gradient over short distances, a function that is extremely important for maintaining renal microcirculation. Regulation of renal microvascular tone is impaired in salt-sensitive (SS) hypertension–induced nephropathy, but the molecular mechanisms contributing to this impairment remain elusive. Here, we assessed the contribution of the SH2 adaptor protein p66Shc (encoded by
Bradley Miller, Oleg Palygin, Victoriya A. Rufanova, Andrew Chong, Jozef Lazar, Howard J. Jacob, David Mattson, Richard J. Roman, Jan M. Williams, Allen W. Cowley Jr., Aron M. Geurts, Alexander Staruschenko, John D. Imig, Andrey Sorokin
Diminished inhibitory neurotransmission in the superficial dorsal horn of the spinal cord is thought to contribute to chronic pain. In inflammatory pain, reductions in synaptic inhibition occur partially through prostaglandin E2- (PGE2-) and PKA-dependent phosphorylation of a specific subtype of glycine receptors (GlyRs) that contain α3 subunits. Here, we demonstrated that 2,6-di-
Mario A. Acuña, Gonzalo E. Yévenes, William T. Ralvenius, Dietmar Benke, Alessandra Di Lio, Cesar O. Lara, Braulio Muñoz, Carlos F. Burgos, Gustavo Moraga-Cid, Pierre-Jean Corringer, Hanns Ulrich Zeilhofer
Preeclampsia is a hypertensive disorder of pregnancy in which patients develop profound sensitivity to vasopressors, such as angiotensin II, and is associated with substantial morbidity for the mother and fetus. Enhanced vasoconstrictor sensitivity and elevations in soluble fms-like tyrosine kinase 1 (sFLT1), a circulating antiangiogenic protein, precede clinical signs and symptoms of preeclampsia. Here, we report that overexpression of
Suzanne D. Burke, Zsuzsanna K. Zsengellér, Eliyahu V. Khankin, Agnes S. Lo, Augustine Rajakumar, Jennifer J. DuPont, Amy McCurley, Mary E. Moss, Dongsheng Zhang, Christopher D. Clark, Alice Wang, Ellen W. Seely, Peter M. Kang, Isaac E. Stillman, Iris Z. Jaffe, S. Ananth Karumanchi
Major depressive disorder (MDD) is a recurring psychiatric illness that causes substantial health and socioeconomic burdens. Clinical reports have revealed that scopolamine, a nonselective muscarinic acetylcholine receptor antagonist, produces rapid antidepressant effects in individuals with MDD. Preclinical models suggest that these rapid antidepressant effects can be recapitulated with blockade of M1-type muscarinic acetylcholine receptors (M1-AChR); however, the cellular mechanisms underlying activity-dependent synaptic and behavioral responses to scopolamine have not been determined. Here, we demonstrate that the antidepressant-like effects of scopolamine are mediated by GABA interneurons in the medial prefrontal cortex (mPFC). Both GABAergic (GAD67+) interneurons and glutamatergic (CaMKII+) interneurons in the mPFC expressed M1-AChR. In mice, viral-mediated knockdown of M1-AChR specifically in GABAergic neurons, but not glutamatergic neurons, in the mPFC attenuated the antidepressant-like effects of scopolamine. Immunohistology and electrophysiology showed that somatostatin (SST) interneurons in the mPFC express M1-AChR at higher levels than parvalbumin interneurons. Moreover, knockdown of M1-AChR in SST interneurons in the mPFC demonstrated that M1-AChR expression in these neurons is required for the rapid antidepressant-like effects of scopolamine. These data indicate that SST interneurons in the mPFC are a promising pharmacological target for developing rapid-acting antidepressant therapies.
Eric S. Wohleb, Min Wu, Danielle M. Gerhard, Seth R. Taylor, Marina R. Picciotto, Meenakshi Alreja, Ronald S. Duman
Primary congenital glaucoma (PCG) is a devastating eye disease and an important cause of childhood blindness worldwide. In PCG, defects in the anterior chamber aqueous humor outflow structures of the eye result in elevated intraocular pressure (IOP); however, the genes and molecular mechanisms involved in the etiology of these defects have not been fully characterized. Previously, we observed PCG-like phenotypes in transgenic mice that lack functional angiopoietin-TEK signaling. Herein, we identified rare
Tomokazu Souma, Stuart W. Tompson, Benjamin R. Thomson, Owen M. Siggs, Krishnakumar Kizhatil, Shinji Yamaguchi, Liang Feng, Vachiranee Limviphuvadh, Kristina N. Whisenhunt, Sebastian Maurer-Stroh, Tammy L. Yanovitch, Luba Kalaydjieva, Dimitar N. Azmanov, Simone Finzi, Lucia Mauri, Shahrbanou Javadiyan, Emmanuelle Souzeau, Tiger Zhou, Alex W. Hewitt, Bethany Kloss, Kathryn P. Burdon, David A. Mackey, Keri F. Allen, Jonathan B. Ruddle, Sing-Hui Lim, Steve Rozen, Khanh-Nhat Tran-Viet, Xiaorong Liu, Simon John, Janey L. Wiggs, Francesca Pasutto, Jamie E. Craig, Jing Jin, Susan E. Quaggin, Terri L. Young
Carlos A. Ramos, Barbara Savoldo, Vicky Torrano, Brandon Ballard, Huimin Zhang, Olga Dakhova, Enli Liu, George Carrum, Rammurti T. Kamble, Adrian P. Gee, Zhuyong Mei, Meng-Fen Wu, Hao Liu, Bambi Grilley, Cliona M. Rooney, Malcolm K. Brenner, Helen E. Heslop, Gianpietro Dotti
Martina Absinta, Pascal Sati, Matthew Schindler, Emily C. Leibovitch, Joan Ohayon, Tianxia Wu, Alessandro Meani, Massimo Filippi, Steven Jacobson, Irene C.M. Cortese, Daniel S. Reich
The extramural General Clinical Research Center (GCRC) program has been funded for more than 50 years, first by the National Center for Research Resources, NIH, and more recently as part of the Clinical Translational Science Award (CTSA) program through the newly formed National Center for Advancing Translation Sciences (NCATS). The GCRCs represent the federally funded laboratories that employ a highly trained cadre of research nurses, dietitians, and other support staff and in which generations of clinical investigators trained and performed groundbreaking human studies that advanced medical science and improved clinical care. Without the opportunity for adequate discussion, NCATS has now stopped funding these Research Centers. In this “eulogy,” we review the origins and history of the GCRCs, their contributions to the advancement of medicine, and the recent events that have essentially defunded them. We mourn their loss.
David G. Nathan, David M. Nathan
The lymphatic vasculature is essential for maintaining interstitial fluid homeostasis, and dysfunctional lymphangiogenesis contributes to various pathological processes, including inflammatory disease and tumor metastasis. Mutations in
Anees Fatima, Ying Wang, Yutaka Uchida, Pieter Norden, Ting Liu, Austin Culver, William H. Dietz, Ford Culver, Meredith Millay, Yoh-suke Mukouyama, Tsutomu Kume
Successful bacterial pathogens produce an array of virulence factors that allow subversion of the immune system and persistence within the host. For example, uropathogenic
Anna Waldhuber, Manoj Puthia, Andreas Wieser, Christine Cirl, Susanne Dürr, Silke Neumann-Pfeifer, Simone Albrecht, Franziska Römmler, Tina Müller, Yunji Zheng, Sören Schubert, Olaf Groß, Catharina Svanborg, Thomas Miethke
High levels of arginine metabolizing enzymes, including inducible nitric oxide synthase (iNOS) and arginase (ARG), are typical in asthmatic airway epithelium; however, little is known about the metabolic effects of enhanced arginine flux in asthma. Here, we demonstrated that increased metabolism sustains arginine availability in asthmatic airway epithelium with consequences for bioenergetics and inflammation. Expression of iNOS, ARG2, arginine synthetic enzymes, and mitochondrial respiratory complexes III and IV was elevated in asthmatic lung samples compared with healthy controls. ARG2 overexpression in a human bronchial epithelial cell line accelerated oxidative bioenergetic pathways and suppressed hypoxia-inducible factors (HIFs) and phosphorylation of the signal transducer for atopic Th2 inflammation STAT6 (pSTAT6), both of which are implicated in asthma etiology.
Weiling Xu, Sudakshina Ghosh, Suzy A.A. Comhair, Kewal Asosingh, Allison J. Janocha, Deloris A. Mavrakis, Carole D. Bennett, Lourdes L. Gruca, Brian B. Graham, Kimberly A. Queisser, Christina C. Kao, Samuel H. Wedes, John M. Petrich, Rubin M. Tuder, Satish C. Kalhan, Serpil C. Erzurum
The molecular mechanisms that underlie spleen development and congenital asplenia, a condition linked to increased risk of overwhelming infections, remain largely unknown. The transcription factor TLX1 controls cell fate specification and organ expansion during spleen development, and
Elisa Lenti, Diego Farinello, Kazunari K. Yokoyama, Dmitry Penkov, Laura Castagnaro, Giovanni Lavorgna, Kenly Wuputra, Lisa L. Sandell, Naomi E. Butler Tjaden, Francesca Bernassola, Nicoletta Caridi, Anna De Antoni, Michael Wagner, Katja Kozinc, Karen Niederreither, Francesco Blasi, Diego Pasini, Gregor Majdic, Giovanni Tonon, Paul A. Trainor, Andrea Brendolan
Loss of the growth-suppressive effects of bone morphogenetic protein (BMP) signaling has been demonstrated to promote pulmonary arterial endothelial cell dysfunction and induce pulmonary arterial smooth muscle cell (PASMC) proliferation, leading to the development of pulmonary arterial hypertension (PAH). MicroRNAs (miRs) mediate higher order regulation of cellular function through coordinated modulation of mRNA targets; however, miR expression is altered by disease development and drug therapy. Here, we examined treatment-naive patients and experimental models of PAH and identified a reduction in the levels of miR-140-5p. Inhibition of miR-140-5p promoted PASMC proliferation and migration in vitro. In rat models of PAH, nebulized delivery of miR-140-5p mimic prevented the development of PAH and attenuated the progression of established PAH. Network and pathway analysis identified SMAD-specific E3 ubiquitin protein ligase 1 (SMURF1) as a key miR-140-5p target and regulator of BMP signaling. Evaluation of human tissue revealed that SMURF1 is increased in patients with PAH. miR-140-5p mimic or SMURF1 knockdown in PASMCs altered BMP signaling, further supporting these factors as regulators of BMP signaling. Finally,
Alexander M.K. Rothman, Nadine D. Arnold, Josephine A. Pickworth, James Iremonger, Loredana Ciuclan, Robert M.H. Allen, Sabine Guth-Gundel, Mark Southwood, Nicholas W. Morrell, Matthew Thomas, Sheila E. Francis, David J. Rowlands, Allan Lawrie
Efficient oxygen utilization in the kidney may be supported by paracellular epithelial transport, a form of passive diffusion that is driven by preexisting transepithelial electrochemical gradients. Claudins are tight-junction transmembrane proteins that act as paracellular ion channels in epithelial cells. In the proximal tubule (PT) of the kidney, claudin-2 mediates paracellular sodium reabsorption. Here, we used murine models to investigate the role of claudin-2 in maintaining energy efficiency in the kidney. We found that claudin-2–null mice conserve sodium to the same extent as WT mice, even during profound dietary sodium depletion, as a result of the upregulation of transcellular Na-K-2Cl transport activity in the thick ascending limb of Henle. We hypothesized that shifting sodium transport to transcellular pathways would lead to increased whole-kidney oxygen consumption. Indeed, compared with control animals, oxygen consumption in the kidneys of claudin-2–null mice was markedly increased, resulting in medullary hypoxia. Furthermore, tubular injury in kidneys subjected to bilateral renal ischemia-reperfusion injury was more severe in the absence of claudin-2. Our results indicate that paracellular transport in the PT is required for efficient utilization of oxygen in the service of sodium transport. We speculate that paracellular permeability may have evolved as a general strategy in epithelial tissues to maximize energy efficiency.
Lei Pei, Glenn Solis, Mien T.X. Nguyen, Nikhil Kamat, Lynn Magenheimer, Min Zhuo, Jiahua Li, Joshua Curry, Alicia A. McDonough, Timothy A. Fields, William J. Welch, Alan S.L. Yu
Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults, and one-third of patients develop end-stage renal disease (ESRD). Circulating autoantibodies against the podocyte surface antigens phospholipase A2 receptor 1 (PLA2R1) and the recently identified thrombospondin type 1 domain–containing 7A (THSD7A) are assumed to cause the disease in the majority of patients. The pathogenicity of these antibodies, however, has not been directly proven. Here, we have reported the analysis and characterization of a male patient with THSD7A-associated MN who progressed to ESRD and subsequently underwent renal transplantation. MN rapidly recurred after transplantation. Enhanced staining for THSD7A was observed in the kidney allograft, and detectable anti-THSD7A antibodies were present in the serum before and after transplantation, suggesting that these antibodies induced a recurrence of MN in the renal transplant. In contrast to PLA2R1, THSD7A was expressed on both human and murine podocytes, enabling the evaluation of whether anti-THSD7A antibodies cause MN in mice. We demonstrated that human anti-THSD7A antibodies specifically bind to murine THSD7A on podocyte foot processes, induce proteinuria, and initiate a histopathological pattern that is typical of MN. Furthermore, anti-THSD7A antibodies induced marked cytoskeletal rearrangement in primary murine glomerular epithelial cells as well as in human embryonic kidney 293 cells. Our findings support a causative role of anti-THSD7A antibodies in the development of MN.
Nicola M. Tomas, Elion Hoxha, Anna T. Reinicke, Lars Fester, Udo Helmchen, Jens Gerth, Friederike Bachmann, Klemens Budde, Friedrich Koch-Nolte, Gunther Zahner, Gabriele Rune, Gerard Lambeau, Catherine Meyer-Schwesinger, Rolf A.K. Stahl
The 5th anniversary of the Fukushima disaster and the 30th anniversary of the Chernobyl disaster, the two most catastrophic nuclear accidents in history, both occurred recently. Images of Chernobyl are replete with the international sign of radioactive contamination (a circle with three broad spokes radiating outward in a yellow sign). In contrast, ongoing decontamination efforts at Fukushima lack international warnings about radioactivity. Decontamination workers at Fukushima appear to be poorly protected against radiation. It is almost as if the effort is to make the Fukushima problem disappear. A more useful response would be to openly acknowledge the monumental problems inherent in managing a nuclear plant disaster. Lessons from Chernobyl are the best predictors of what the Fukushima region of Japan is coping with in terms of health and environmental problems following a nuclear catastrophe.
Andrew R. Marks