Iron deficiency is common worldwide and is associated with adverse pregnancy outcomes. The increasing prevalence of indiscriminate iron supplementation during pregnancy also raises concerns about the potential adverse effects of iron excess. We examined how maternal iron status affects the delivery of iron to the placenta and fetus. Using mouse models, we documented maternal homeostatic mechanisms which protect the placenta and fetus from maternal iron excess. We determined that under physiological conditions or in iron deficiency, fetal and placental hepcidin does not regulate fetal iron endowment. With maternal iron deficiency, critical transporters mediating placental iron uptake (transferrin receptor 1, TFR1) and export (ferroportin, FPN) were strongly regulated. In mice, not only was TFR1 increased but FPN was surprisingly decreased to preserve placental iron, in the face of fetal iron deficiency. In human placentas from pregnancies with mild iron deficiency, TFR1 was increased but without a change in FPN. However, induction of more severe iron deficiency in human trophoblast in vitro resulted in the regulation of both TFR1 and FPN, similarly to the mouse model. This placental adaptation prioritizing placental iron is mediated by the iron-regulatory protein 1 and is important for the maintenance of mitochondrial respiration, thus ultimately protecting the fetus from the potentially dire consequences of generalized placental dysfunction.
Veena Sangkhae, Allison L. Fisher, Shirley Wong, Mary Dawn Koenig, Lisa Tussing-Humphreys, Alison Chu, Melisa Lelić, Tomas Ganz, Elizabeta Nemeth
CD8+ T cell responses are necessary for immune control of simian immunodeficiency virus (SIV). However, the key parameters that dictate antiviral potency remain elusive, conceivably because most studies to date have been restricted to analyses of circulating CD8+ T cells. We conducted a detailed clonotypic, functional, and phenotypic survey of SIV-specific CD8+ T cells across multiple anatomical sites in chronically infected rhesus macaques with high (> 10,000 copies/mL plasma) or low burdens of viral RNA (< 10,000 copies/mL plasma). No significant differences in response magnitude were identified across anatomical compartments. Rhesus macaques with low viral loads (VLs) harbored higher frequencies of polyfunctional CXCR5+ SIV-specific CD8+ T cells in various lymphoid tissues and higher proportions of unique Gag-specific CD8+ T cell clonotypes in the mesenteric lymph nodes relative to rhesus macaques with high VLs. In addition, public Gag-specific CD8+ T cell clonotypes were more commonly shared across distinct anatomical sites than the corresponding private clonotypes, which tended to form tissue-specific repertoires, especially in the peripheral blood and the gastrointestinal tract. Collectively, these data suggest that functionality and tissue localization are important determinants of CD8+ T cell-mediated efficacy against SIV.
Carly E. Starke, Carol L. Vinton, Kristin Ladell, James E. McLaren, Alexandra M. Ortiz, Joseph C. Mudd, Jacob K. Flynn, Stephen H. Lai, Fan Wu, Vanessa M. Hirsch, Samuel Darko, Daniel C. Douek, David A. Price, Jason M. Brenchley
Tuberculosis (TB) remains a major infectious disease worldwide. TB treatment displays a bi-phasic bacterial clearance, in which the majority of bacteria clear within the first month of treatment, but residual bacteria remains non-responsive to treatment and eventually may become resistant. Here, we have shown that Mycobacterium tuberculosis (M.tb) is taken up by mesenchymal stem cells (MSCs), where it established dormancy and became highly non-responsive to isoniazid, a major constituent of Directly Observed Treatment Short-course (DOTS). Dormant M.tb induced quiescence in MSCs and promoted their long-term survival. Unlike macrophages, where M.tb resides in early-phagosomal compartments, in MSCs the majority of bacilli were found in the cytosol, where they promoted rapid lipid-synthesis, hiding within lipid-droplets. Inhibition of lipid-synthesis prevented dormancy and sensitized the organisms to isoniazid. Thus, we have established that M.tb gains dormancy in MSCs, which thus serve as a long-term natural-reservoir of dormant M.tb. Interestingly, in the murine-model of TB, induction of autophagy eliminated M.tb from MSCs and consequently, the addition of rapamycin to an isoniazid treatment regimen successfully attained sterile clearance and prevented disease reactivation.
Samreen Fatima, Shashank Shivaji Kamble, Ved Prakash Dwivedi, Debapriya Bhattacharya, Santosh Kumar, Anand Ranganathan, Luc Van Kaer, Sujata Mohanty, Gobardhan Das
β-thalassemia is a genetic anemia caused by partial or complete loss of β-globin synthesis leading to ineffective erythropoiesis and RBCs with short life-span. Currently, there is no efficacious oral medication modifying anemia for patients with beta-thalassemia. The inappropriately low levels of the iron regulatory hormone hepcidin enable excessive iron absorption by ferroportin, the unique cellular iron exporter in mammals, leading to organ iron overload and associated morbidities. Correction of unbalanced iron absorption and recycling by induction of hepcidin synthesis or treatment with hepcidin mimetics ameliorates β-thalassemia. However, hepcidin modulation or replacement strategies currently in clinical development all require parenteral drug administration. We identified oral ferroportin inhibitors by screening a library of small molecular weight compounds for modulators of ferroportin internalization. Restricting iron availability by VIT-2763, the first clinical stage oral ferroportin inhibitor, ameliorated anemia and the dysregulated iron homeostasis in the Hbbth3/+ mouse model of beta-thalassemia intermedia. VIT-2763 not only improved erythropoiesis but also corrected the proportions of myeloid precursors in spleens of Hbbth3/+ mice. VIT-2763 is currently developed as an oral drug targeting ferroportin for the treatment of β-thalassemia.
Vania Manolova, Naja Nyffenegger, Anna Flace, Patrick Altermatt, Ahmet Varol, Cédric Doucerain, Hanna Sundstrom, Franz Dürrenberger
Vascular Ehlers-Danlos syndrome (vEDS) is an autosomal-dominant connective tissue disorder caused by heterozygous mutations in the COL3A1 gene, which encodes the pro-alpha 1 chain of collagen III. Loss of structural integrity of the extracellular matrix is believed to drive the signs and symptoms of this condition, including spontaneous arterial dissection and/or rupture, the major cause of mortality. We created two mouse models of vEDS that carry heterozygous mutations in Col3a1 that encode glycine substitutions analogous to those found in patients, and showed that signaling abnormalities in the PLC/IP3/PKC/ERK pathway (phospholipase C/inositol 1,4,5-triphosphate/protein kinase C/extracellular signal-regulated kinase) are major mediators of vascular pathology.Treatment with pharmacologic inhibitors of ERK1/2 or PKC-beta prevented death due to spontaneous aortic rupture. Additionally, we found that pregnancy- and puberty-associated accentuation of vascular risk, also seen in vEDS patients, is rescued by attenuation of oxytocin and androgen signaling, respectively. Taken together, our results provide evidence that targetable signaling abnormalities contribute to the pathogenesis of vEDS, highlighting unanticipated therapeutic opportunities.
Caitlin J. Bowen, Juan Francisco Calderón Giadrosic, Zachary Burger, Graham Rykiel, Elaine C. Davis, Mark R. Helmers, Kelly Benke, Elena Gallo MacFarlane, Harry C. Dietz
Recent occurrences of filoviruses and the arenavirus Lassa virus (LASV) in overlapping endemic areas of Africa highlight the need for a prophylactic vaccine that would confer protection against all of these viruses that cause lethal hemorrhagic fever (HF). We developed a quadrivalent formulation of Vesiculovax that contains recombinant vesicular stomatitis virus (rVSV) vectors expressing filovirus glycoproteins and also contains a rVSV vector expressing the glycoprotein of a lineage IV strain of LASV. Cynomolgus macaques were vaccinated twice with the quadrivalent formulation, followed by challenge 28 days after the boost vaccination with each of the three corresponding filoviruses (Ebola, Sudan, Marburg) or a heterologous contemporary lineage II strain of LASV. Serum IgG and neutralizing antibody responses specific for all four glycoproteins were detected in all vaccinated animals. A modest and balanced cell-mediated immune response specific for the glycoproteins was also detected in most of the vaccinated macaques. Regardless of the levels of total glycoprotein-specific immune response detected after vaccination, all immunized animals were protected from disease and death following lethal challenges. These findings indicate that vaccination with attenuated rVSV vectors each expressing a single HF virus glycoprotein may provide protection against those filoviruses and LASV most commonly responsible for outbreaks of severe HF in Africa.
Robert W. Cross, Rong Xu, Demetrius Matassov, Stefan Hamm, Theresa E. Latham, Cheryl S. Gerardi, Rebecca M. Nowak, Joan B. Geisbert, Ayuko Ota-Setlik, Krystle N. Agans, Amara Luckay, Susan E. Witko, Lena Soukieh, Daniel J. Deer, Chad E. Mire, Heinz Feldmann, Christian Happi, Karla A. Fenton, John H. Eldridge, Thomas W. Geisbert
Pancreatic ductal adenocarcinoma (PDAC) is considered to be a highly immunosuppressive and heterogenous neoplasm. Despite improved knowledge regarding the genetic background of the tumor and better understanding of the tumor microenvironment, immune checkpoint inhibitor therapy (targeting CTLA4, PD1, PDL1) has not been very successful against PDAC. The robust desmoplastic stroma, along with an extensive extracellular matrix (ECM) that is rich in hyaluronan, plays an integral role in this immune evasion. Hexosamine biosynthesis pathway (HBP), a shunt pathway of glycolysis, is a metabolic node in cancer cells that can promote survival pathways on one hand and influence the hyaluronan synthesis in the ECM on the other. The rate-limiting enzyme of the pathway, glutamine-fructose amidotransferase (GFAT1), uses glutamine and fructose 6-phosphate to eventually synthesize UDP-GlcNAc. In the current manuscript, we targeted this glutamine-utilizing enzyme by a small molecule glutamine analog (6-diazo-5-oxo-L-norleucine or DON). Our results showed that DON decreased the self-renewal potential and metastatic ability of tumor cell. Further, treatment with DON decreased hyaluronan and collagen in the tumor microenvironment, leading to an extensive remodeling of the ECM, and an increased infiltration CD8+ T-cells. Additionally, treatment with DON sensitized pancreatic tumors to anti-PD1 therapy resulting in tumor regression and prolonged survival.
Nikita S. Sharma, Vineet K. Gupta, Vanessa T. Garrido, Roey Hadad, Brittany C. Durden, Kousik Kesh, Bhuwan Giri, Anthony Ferrantella, Vikas Dudeja, Ashok Saluja, Sulagna Banerjee
Background: Proteinuria is considered as an unfavorable clinical condition that accelerates renal and cardiovascular disease. However, it is not clear if all forms of proteinuria are damaging. Mutations in CUBN cause Imerslund-Gräsbeck syndrome (IGS) featured by intestinal malabsorption of vitamin B12 and in some cases proteinuria. CUBN encodes for cubilin, an intestinal and proximal tubular uptake receptor containing 27 CUB domains for ligand binding. Methods: We used next-generation sequencing for renal disease genes to genotype cohorts of patients with suspected hereditary renal disease and chronic proteinuria. CUBN variants were analyzed using bioinformatics, structural modeling and epidemiological methods. Results: We identified 39 patients, in whom biallelic pathogenic variants in the CUBN gene are associated with chronic isolated proteinuria with childhood onset. Since the proteinuria displayed a high proportion of albuminuria, glomerular diseases such as steroid-resistant nephrotic syndrome or Alport syndrome were often the primary clinical diagnosis, motivating renal biopsies and proteinuria-lowering treatments. Yet, renal function was normal in all cases. By contrast, we did not find any biallelic pathogenic CUBN variants in patients with reduced renal function or focal segmental glomerulosclerosis. Unlike the more N-terminal IGS mutations, 37 out of the 41 proteinuria-associated CUBN variants led to modifications or truncations after the vitamin B12-binding domain. Finally, we show that four C-terminal CUBN variants are associated with albuminuria and moderately increased GFR in meta-analyses of large population-based cohorts. Conclusions: Collectively, our data suggest an important role for the C-terminal half of cubilin in renal albumin reabsorption. Albuminuria due to reduced cubilin function could be an unexpectedly common benign condition in humans that may not require any proteinuria-lowering treatment or renal biopsies.
Mathilda Bedin, Olivia Boyer, Aude Servais, Yong Li, Laure Villoing-Gaudé, Marie-Josephe Tête, Alexandra Cambier, Julien Hogan, Veronique Baudouin, Saoussen Krid, Albert Bensman, Florie Lammens, Ferielle Louillet, Bruno Ranchin, Cecile Vigneau, Iseline Bouteau, Corinne Isnard-Bagnis, Christoph J. Mache, Tobias Schäfer, Lars Pape, Markus Gödel, Tobias B. Huber, Marcus Benz, Günter Klaus, Matthias Hansen, Kay Latta, Olivier Gribouval, Vincent Morinière, Carole Tournant, Maik Grohmann, Elisa Kuhn, Timo Wagner, Christine Bole-Feysot, Fabienne Jabot-Hanin, Patrick Nitschké, Tarunveer S. Ahluwalia, Anna Köttgen, Christian Brix Folsted Andersen, Carsten Bergmann, Corinne Antignac, Matias Simons
Tyrosine kinase inhibitors (TKIs) induce molecular remission in the majority of patients with chronic myelogenous leukemia (CML), but persistence of CML stem cells hinders cure and necessitates indefinite TKI therapy. We report that CML stem cells upregulate expression of pleiotrophin (PTN) and require cell-autonomous PTN signaling for CML pathogenesis in BCR/ABL+ mice. Constitutive PTN deletion substantially reduced the numbers of CML stem cells capable of initiating CML in vivo. Hematopoietic cell–specific deletion of PTN suppressed CML development in BCR/ABL+ mice, suggesting that cell-autonomous PTN signaling was necessary for CML disease evolution. Mechanistically, PTN promoted CML stem cell survival and TKI resistance via induction of Jun and the unfolded protein response. Human CML cells were also dependent on cell-autonomous PTN signaling and anti–PTN antibody suppressed human CML colony formation and CML repopulation in vivo. Our results suggest that targeted inhibition of PTN has therapeutic potential to eradicate CML stem cells.
Heather A. Himburg, Martina Roos, Tiancheng Fang, Yurun Zhang, Christina M. Termini, Lauren Schlussel, Mindy M. Kim, Amara Pang, Jenny Kan, Liman Zhao, Hyung Suh, Joshua P. Sasine, Gopal Sapparapu, Peter M. Bowers, Gary Schiller, John P. Chute
Novel approaches for adjunctive therapy are urgently needed for infections complicated by antibiotic-resistant pathogens and for patients with compromised immunity. Necrotizing fasciitis (NF) is a destructive skin and soft tissue infection. Despite treatment with systemic antibiotics and radical debridement of necrotic tissue, lethality remains high. The key iron regulatory hormone hepcidin was originally identified as a cationic antimicrobial peptide (AMP), but its putative expression and role in the skin, a major site of AMP production, has never been investigated. We report here that hepcidin production is induced in the skin of patients with Group A Streptococcal (GAS) NF. In a GAS-induced NF model, mice lacking hepcidin in keratinocytes failed to restrict systemic spread of infection from an initial tissue focus. Unexpectedly, this effect was due its ability to promote production of the CXCL1 chemokine by keratinocytes resulting in neutrophil recruitment. Unlike CXCL1, hepcidin is resistant to degradation by major GAS proteases and could therefore serve as a reservoir to maintain steady state levels of CXCL1 in infected tissue. Finally, injection of synthetic hepcidin at the site of infection can limit or completely prevent systemic spread of GAS infection suggesting that hepcidin agonists could have a therapeutic role in NF.
Mariangela Malerba, Sabine Louis, Sylvain Cuvellier, Srikanth Mairpady Shambat, Camille Hua, Camille Gomart, Agnès Fouet, Nicolas Ortonne, Jean-Winoc Decousser, Annelies S. Zinkernagel, Jacques R.R. Mathieu, Carole Peyssonnaux
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