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Zhi X, Zhou XE, Melcher K, Motola DL, Gelmedin V, Hawdon J, Kliewer SA, Mangelsdorf DJ, Xu HE. Structural conservation of ligand binding reveals a bile acid-like signaling pathway in nematodes. J Biol Chem 2012; 287:4894-903. [PMID: 22170062 PMCID: PMC3281614 DOI: 10.1074/jbc.m111.315242] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 11/23/2011] [Indexed: 01/28/2023] Open
Abstract
Bile acid-like molecules named dafachronic acids (DAs) control the dauer formation program in Caenorhabditis elegans through the nuclear receptor DAF-12. This mechanism is conserved in parasitic nematodes to regulate their dauer-like infective larval stage, and as such, the DAF-12 ligand binding domain has been identified as an important therapeutic target in human parasitic hookworm species that infect more than 600 million people worldwide. Here, we report two x-ray crystal structures of the hookworm Ancylostoma ceylanicum DAF-12 ligand binding domain in complex with DA and cholestenoic acid (a bile acid-like metabolite), respectively. Structure analysis and functional studies reveal key residues responsible for species-specific ligand responses of DAF-12. Furthermore, DA binds to DAF-12 mechanistically and is structurally similar to bile acids binding to the mammalian bile acid receptor farnesoid X receptor. Activation of DAF-12 by cholestenoic acid and the cholestenoic acid complex structure suggest that bile acid-like signaling pathways have been conserved in nematodes and mammals. Together, these results reveal the molecular mechanism for the interplay between parasite and host, provide a structural framework for DAF-12 as a promising target in treating nematode parasitism, and provide insight into the evolution of gut parasite hormone-signaling pathways.
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Affiliation(s)
| | | | - Karsten Melcher
- From the Laboratory of Structural Sciences and
- Laboratory of Structural Biology and Biochemistry, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | | | - Verena Gelmedin
- the Department of Microbiology, Immunology, and Tropical Medicine, George Washington University Medical Center, Washington, D. C. 20037, and
| | - John Hawdon
- the Department of Microbiology, Immunology, and Tropical Medicine, George Washington University Medical Center, Washington, D. C. 20037, and
| | | | - David J. Mangelsdorf
- the Departments of Pharmacology and
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - H. Eric Xu
- From the Laboratory of Structural Sciences and
- the VARI-SIMM Center, Center for Structure and Function of Drug Targets, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
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2
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Kouyos RD, Abel Zur Wiesch P, Bonhoeffer S. On being the right size: the impact of population size and stochastic effects on the evolution of drug resistance in hospitals and the community. PLoS Pathog 2011; 7:e1001334. [PMID: 21533212 PMCID: PMC3077359 DOI: 10.1371/journal.ppat.1001334] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 03/15/2011] [Indexed: 11/18/2022] Open
Abstract
The evolution of drug resistant bacteria is a severe public health problem, both in hospitals and in the community. Currently, some countries aim at concentrating highly specialized services in large hospitals in order to improve patient outcomes. Emergent resistant strains often originate in health care facilities, but it is unknown to what extent hospital size affects resistance evolution and the resulting spillover of hospital-associated pathogens to the community. We used two published datasets from the US and Ireland to investigate the effects of hospital size and controlled for several confounders such as antimicrobial usage, sampling frequency, mortality, disinfection and length of stay. The proportion of patients acquiring both sensitive and resistant infections in a hospital strongly correlated with hospital size. Moreover, we observe the same pattern for both the percentage of resistant infections and the increase of hospital-acquired infections over time. One interpretation of this pattern is that chance effects in small hospitals impede the spread of drug-resistance. To investigate to what extent the size distribution of hospitals can directly affect the prevalence of antibiotic resistance, we use a stochastic epidemiological model describing the spread of drug resistance in a hospital setting as well as the interaction between one or several hospitals and the community. We show that the level of drug resistance typically increases with population size: In small hospitals chance effects cause large fluctuations in pathogen population size or even extinctions, both of which impede the acquisition and spread of drug resistance. Finally, we show that indirect transmission via environmental reservoirs can reduce the effect of hospital size because the slow turnover in the environment can prevent extinction of resistant strains. This implies that reducing environmental transmission is especially important in small hospitals, because such a reduction not only reduces overall transmission but might also facilitate the extinction of resistant strains. Overall, our study shows that the distribution of hospital sizes is a crucial factor for the spread of drug resistance. The increasing spread of bacteria, which are resistant to antibiotics, is a serious threat to clinical care. Currently, several countries aim at concentrating highly specialized services in large hospitals in order to improve patient outcomes. However, empirical studies have shown that resistance levels correlate with hospital size. To illustrate this correlation, we analyze two published datasets from the US and Ireland and controlled for antimicrobial usage, disinfection and length of stay. The proportion of patients acquiring both sensitive and resistant infections in hospitals strongly correlated with hospital size. Moreover, we observe the same pattern for both the percentage of resistant infections and the temporal increase of hospital-acquired infections. To investigate to what extent hospital size can directly affect the prevalence of antibiotic resistance, we use mathematical models describing the epidemic spread of resistance in hospitals and the community. We find that small hospitals typically lead to considerably lower resistance levels than large hospitals. However, this beneficial effect of small hospital size may be reduced if bacteria are transmitted indirectly via the environment. Therefore, reducing environmental transmission might be particularly important in small hospitals. Overall, our findings suggest that the short-term benefits of larger hospitals may come at the price of increasing resistance in the long term.
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Affiliation(s)
- Roger D Kouyos
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland.
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3
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Abstract
Hookworm infection is associated with growth delay and iron deficiency anemia in developing countries. A series of experiments were designed in order to test the hypothesis that host dietary iron restriction mediates susceptibility to hookworm infection using the hamster model of Ancylostoma ceylanicum. Animals were maintained on diets containing either 10 ppm iron (iron restricted) or 200 ppm iron (standard/high iron), followed by infection with A. ceylanicum third-stage larvae. Infected animals fed the standard diet exhibited statistically significant growth delay and reduced blood hemoglobin levels compared to uninfected controls on day 20 postinfection. In contrast, no statistically significant differences in weight or hemoglobin concentration were observed between infected and uninfected animals fed the iron-restricted diet. Moreover, iron-restricted animals were observed to have reduced intestinal worm burdens on day 10 and day 20 postinfection compared to those of animals maintained on the standard/high-iron diet. In a subsequent study, animals equilibrated on diets containing a range of iron levels (10 ppm, 40 ppm, 100 ppm, or 200 ppm) were infected with A. ceylanicum and followed for evidence of hookworm disease. Infected animals from the intermediate-dietary iron (40- and 100-ppm) groups exhibited greater weight loss and anemia than those in the low (10-ppm)- or high (200-ppm)-iron diet groups. Mortality was also significantly higher in the intermediate-dietary-iron groups. These data suggest that severe dietary iron restriction impairs hookworm development in vivo but that moderate iron restriction enhances host susceptibility to severe disease.
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Affiliation(s)
- Melissa R Held
- Program in International Child Health, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA
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Williamson AL, Lecchi P, Turk BE, Choe Y, Hotez PJ, McKerrow JH, Cantley LC, Sajid M, Craik CS, Loukas A. A Multi-enzyme Cascade of Hemoglobin Proteolysis in the Intestine of Blood-feeding Hookworms. J Biol Chem 2004; 279:35950-7. [PMID: 15199048 DOI: 10.1074/jbc.m405842200] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Blood-feeding pathogens digest hemoglobin (Hb) as a source of nutrition, but little is known about this process in multicellular parasites. The intestinal brush border membrane of the canine hookworm, Ancylostoma caninum, contains aspartic proteases (APR-1), cysteine proteases (CP-2), and metalloproteases (MEP-1), the first of which is known to digest Hb. We now show that Hb is degraded by a multi-enzyme, synergistic cascade of proteolysis. Recombinant APR-1 and CP-2, but not MEP-1, digested native Hb and denatured globin. MEP-1, however, did cleave globin fragments that had undergone prior digestion by APR-1 and CP-2. Proteolytic cleavage sites within the Hb alpha and beta chains were determined for the three enzymes, identifying a total of 131 cleavage sites. By scanning synthetic combinatorial peptide libraries with each enzyme, we compared the preferred residues cleaved in the libraries with the known cleavage sites within Hb. The semi-ordered pathway of Hb digestion described here is surprisingly similar to that used by Plasmodium to digest Hb and provides a potential mechanism by which these hemoglobinases are efficacious vaccines in animal models of hookworm infection.
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Affiliation(s)
- Angela L Williamson
- Department of Microbiology and Tropical Medicine, The George Washington University, Washington, DC 20037, USA
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5
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Abstract
Infection of golden hamsters with Ancylostoma ceylanicum caused significant decrease in body weight, liver weight and the protein content of liver plasma membrane. Significant inhibition of liver plasma membrane enzymes activities-5'Nucleotidase, gamma-glutamyl transpeptidase, NADHK3Fe (CN)6 reductase, Na+/K(+)-ATPase, CA(2+)-ATPase and Mg(2+)-ATPase was observed in infected animals compared to corresponding controls. Sialic acid content and phospholipid/cholesterol ratio in liver plasma membrane of the infected group were significantly reduced. The study suggests that changes in both the structural and functional organization of membrane may be a biochemical basis of the hepatotoxic effects.
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Abstract
Ancylostoma duodenale and Necator americanus are extremely common species of soil-transmitted helminth which flourish where poverty and malnutrition prevail. Hookworms contribute significantly to iron-deficiency anaemia, which remains one of the world's major nutritional problems, through the feeding activities of intestinal stages leading to chronic blood loss into the gut. In this article, a mathematical model is proposed to explain how human iron metabolism may respond to hookworm infection of varying intensity. The model draws attention to the importance of the regulation of stored iron levels in the process. The results from the model are presented for the effects of hookworm infection on the iron metabolism of a healthy adult male. Calculations are also presented in which the effects of hookworms on the iron metabolism of a non-pregnant woman are compared with those of a pregnant woman. Use of the model may help develop a better understanding of the pathology of hookworm disease.
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Affiliation(s)
- D W Crompton
- Department of Zoology, University of Glasgow, Scotland, UK
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Tekwani BL, Tripathi LM, Mukerjee S, Gupta S, Pandey VC, Katiyar JC, Ghatak S, Shukla OP. Hepatic microsomal cytochrome P450 system during experimental hookworm infection. Exp Mol Pathol 1990; 52:330-9. [PMID: 2369936 DOI: 10.1016/0014-4800(90)90073-m] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Experimental infection of golden hamsters with the hookworm, Ancylostoma ceylanicum, caused a profound decline in the hepatic microsomal cytochrome P450 content. Concomitant decrease was also noticed in aminopyrine N-demethylase and benzo[a]pyrene hydroxylase activities. However, aniline hydroxylase activity was only marginally elevated during the infection. Microsomal markers, viz., cytochrome b5, NADH-cytochrome-c reductase, and glucose-6-phosphatase, were not significantly altered. Hepatic tissue exhibited an accumulation of lipids, especially phospholipids, triglycerides, and cholesterol, resulting in fatty necrosis around the central vein region. Isolated hepatic microsomes showed a decrease in phosphatidylcholine content. Impairment in hepatic mixed function oxidase (MFO) activities was further confirmed by prolongation in hexobarbital sleeping time and zoxazolamine-induced paralysis. The hepatic MFO system of A. ceylanicum-infected hamsters responded qualitatively and quantitatively in a manner similar to that of control hamsters, upon stimulation with selective chemical inducers like phenobarbitone and 3-methylcholanthrene. Kinetic and in vitro substrate binding studies revealed that for aminopyrine the substrate affinity and the maximum enzyme activity (Vmax) were decreased, while for aniline the binding affinity was decreased and the binding capacity was enhanced. Results indicate specific/selective impairment of the hepatic microsomal cytochrome P450 system during hookworm infection and may have many practical implications in toxicology and pharmacology.
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Affiliation(s)
- B L Tekwani
- Central Drug Research Institute, Lucknow, India
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8
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Dotsenko VA, Ordyntseva AP, Makarova TA, Shirinian AA, Lysakova LA. [Experience with the use of nemocide (pyrantel pamoate) in nematodiases]. Med Parazitol (Mosk) 1989:36-9. [PMID: 2615709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The clinical efficacy of and tolerance to the nemocide pyranthel pamoate produced by "IPCA" (India) and applied to nematodiasis treatment have been investigated. A high efficacy of the drug (94.4-100%) for ascariasis, enterobiasis and ancylostomiasis treatment has been established. The drug is well tolerated by adults and induces slight short-term alterations of hepatic functional activity in 5-10-year-old children.
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Mukerjee S, Tekwani BL, Tripathi LM, Maitra SC, Visen PK, Katiyar JC, Ghatak S. Biochemical and histopathological alterations in golden hamster during infection with Ancylostoma ceylanicum. Exp Mol Pathol 1988; 49:50-61. [PMID: 3396668 DOI: 10.1016/0014-4800(88)90020-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Ancylostoma ceylanicum infection in golden hamsters (Mesocricetus auratus) caused marked biochemical and histopathological derangements. Jejunum, the primary site of infection, showed pronounced alterations compared with liver. Though the biochemical composition of jejunum was not significantly altered, activities of a few lysosomal enzymes were enhanced during hookworm infection. Marked damage to mitochondrial and microsomal membranes was reflected in changes in the activities of the marker enzymes from jejunal tissue. Lipid content, especially phospholipids and neutral lipids of hepatic tissue, exhibited marked elevation. Levels of hexokinase, phosphofructokinase, and lactate dehydrogenase were enhanced in jejunal as well as hepatic tissues, indicating activation of the glycolytic machinery during hookworm infection. A decrease in the levels of mucosal disaccharidases indicated damage to intestinal brush border membranes. However, alkaline phosphatase activity was increased in intestinal mucosa during the infection. Light microscopic examination of jejunal tissue revealed peeling off of the upper epithelial layer, activation of the goblet cells, and thickening of muscularis mucosa. However, hepatic tissue did not show gross alterations, except for slight necrosis in the centrilobular region.
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Affiliation(s)
- S Mukerjee
- Division of Biochemistry, Central Drug Research Institute, Lucknow, India
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Kumar N, Gupta PS, Saha K, Misra RC, Agarwal DS, Chuttani HK. Serum and intestinal immunoglobulins in patients of ancylostomiasis. Indian J Med Res 1980; 71:531-7. [PMID: 7390592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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11
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Sinha AK, Sahai BN, Prasad G. Histochemical studies on experimental pups infected with canine and human strains of hookworms. Indian J Med Res 1978; 67:42-7. [PMID: 658995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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12
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Vieira RA. [Pathology of experimental ancylostomiasis in dogs (Anclostoma caninum) studied by radioisotopes. 2. Metabolism of albumin (Risa I 131). Comparative study with human ancylostomiasis]. An Inst Hig Med Trop (Lisb) 1975; 3:331-47. [PMID: 1235042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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13
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Migasena S, Gilles HM, Maegraith BG. Studies in Ancylostoma caninum infection in dogs. I. Absorbtion from the small intestine of amino-acids, carbohydrates and fat. Ann Trop Med Parasitol 1972; 66:107-28. [PMID: 5021561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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14
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Banerjee D, Prakash O, Deo MG. The effects of Ancylostoma caninum on the liver and lung of mice as shown by histochemical techniques. Indian J Med Res 1972; 60:226-32. [PMID: 5035194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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15
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Vieira RA. [Human ancylostomiasis in Cape Verde. Contribution to the study of the parasite]. An Esc Nacl Saude Publica Med Trop (Lisb) 1970; 4:3-227. [PMID: 5534661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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16
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Farid Z, Bassily S, Lehman JS, Kent DC, Haxton J, Patwardhan VN, Hassan A. Iron loss and reabsorption in Ancylostoma duodenale infection and bilharzial colonic polyposis. Trans R Soc Trop Med Hyg 1970; 64:881-4. [PMID: 5495636 DOI: 10.1016/0035-9203(70)90106-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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17
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Aziz MA, Siddiqui AR. Morphological and absorption studies of small intestine in hookworm disease (ancylostomiasis) in West Pakistan. Gastroenterology 1968; 55:242-50. [PMID: 5663089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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18
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Granz W, Mujica M. [Studies on gaseous metabolism in tropical and globally distributed helminthiases]. Arch Hyg Bakteriol 1968; 152:132-8. [PMID: 5707377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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19
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Abdel-Tawab GA, Saad AA, Ibrahim EK, Moustafa MH, Mousa AH, Abdel-Wahab AF. Tryptophan metabolism in some intestinal helminthiases. Trans R Soc Trop Med Hyg 1968; 62:243-50. [PMID: 5643172 DOI: 10.1016/0035-9203(68)90164-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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