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Dr. Kenneth M. Pfarr

Posted January 25th, 2012 by KenPfarr

Research Focus 

The filarial nematodes Wuchereria bancrofti, Brugia malayi and Onchocerca volvulus are round worms that infect humans and cause the diseases lymphatic filariasis (lymphedema and hydrocele) and onchocerciasis (river blindness). An estimated 200 million people are infected with these worms and, in a proportion of the infected population, cause severe morbidity and even death. Current drugs used to interrupt the transmission of these worms to uninfected persons, while very effective at killing the first stage larvae, present with problems. The drugs require several years of annual administration (5-15 years). Additionally, there is evidence for resistance developing.
 
All three of these filarial nematodes contain essential, obligate endosymbiotic bacteria of the genus Wolbachia. Using tetracycline or derivatives of tetracycline (doxycycline), Wolbachia can be depleted from worms in infected animal models of filariasis and human patients. Worms that have been depleted of their endosymbionts are no longer to develop. In adult female worms, depletion of Wolbachia results in a permanent block in oogenesis and embryogenesis. Recently, we have shown that depletion of the endobacteria from W. bancrofti and O. volvulus results in death of the adult worms at the site of infection. Because of these spectacular effects, Wolbachia have gained great interest as targets for controlling filarial infections. However, little is known about the endosymbiotic relationship between Wolbachia and their nematode hosts.
 
My group has three research areas. The first is to understand the symbiosis between Wolbachia and filarial nematodes at the molecular level. One way to research this question is to characterize nematode genes that are differentially regulated during tetracycline treatment to deplete the endobacteria. Using this method, we have successfully identified a phosphate permease that is up-regulated in female and male worms as Wolbachia are depleted. Recently we have extended these results using the B. malayi micro-array chip to identify more genes that may be involved in symbiosis.
 
The second research area is to understand Wolbachia microbiology/biochemistry. The genome for Wolbachia has been sequenced and annotated. Analyzing the genome data has yielded some interesting questions. Of particular interest to my group is the Lipid II biosynthesis pathway, the core molecule for peptidoglycan synthesis. The Wolbachia genome encodes the genes necessary to make Lipid II. However, it lacks several essential proteins needed for downstream events in the synthesis of peptidoglycan (e.g. a cell wall), suggesting that any peptidogylcan-like molecule will be very different from that in other gram-negative bacteria. We are characterizing the functionality of the Lipid II biosynthesis proteins from Wolbachia by expressing recombinant proteins for in vitro Lipid II synthesis and isolating cell membranes from Wolbachia for ex vivo synthesis experiments.
 
The third research area in my lab is the genetics of lymphatic filariasis. Although ~150 million people are infected with the filarial worms W. bancrofti or B. malayi, only a small percentage develop lymphatic filarial pathology. Studies have shown that lymphedema clusters in families independent of environmental factors. Using a candidate gene approach, we have shown that single nucleotide polymorphisms (SNPs) in VEGF-A are associated with hydrocele. Further work is underway to genotype SNPs of cytokines, chemokines and vascular endothelial growth factors for association with lymphatic filariasis. We are also recruiting a large cohort of volunteers for a genome-wide scan project to identify genes involved in pathology.
 
Understanding these three areas will provide the information to drive the search for novel antibiotics to control filarial infections. This could result from a novel target identified in the microarray study, or use cell wall biosynthesis, which is empirically the best target for antibiotics. Additionally, knowing genetic factors that make people susceptible to infection or filarial pathology will allow for the development of screening tests to identify persons and families that could benefit from more personalized physician guidance to help prevent or ameliorate pathology.

 

Dr. Kenneth Pfarr

Group Leader

Phone:  +49-228-287-11207

Fax.:  +49-228-287-11167

Email:  pfarr @ microbiology - bonn.de

Funding: DFG PF673/3-1, PF673/4-1; BMBF IND 10/016 

Dr. Andrea Schiefer

Post-Doc

Phone.:  +49-228-287-11476

Fax.: +49-228-287-11167

Email:  andrea.schiefer @ uni-bonn.de

Project:  Characterization of cell wall biosynthesis in Wolbachia, endosymbionts of filarial nematodes

 

Dr. Anna Albers

Post-Doc

Phone: +49-228-287-11059

Fax.: +49-228-287-11167

Email: albers @ microbiology-bonn.de

Project:  Genotyping of single nucleotide polymorphisms in  patients with lymphatic filariasis disease (lymphedema and hydrocele).

Technicians

Katharina Gorski-Rzepinski

Helene Neufeld

Phone.:  +49-228-287-11510

Fax.: +49-228-287-11167

Students

Valerie Biewener

Ph.D. candidate

Project: Wolbachia cell wall biosynthesis, function of penicillin binding proteins in the absence of peptidoglycan

Christian Lentz

Ph.D. candidate

Project:  Novel anti-wolbachial drug discovery using RNA aptamers and small molecule library screening. 

Uta Strübing

Ph.D. candidate

Project:  Analysis of nematode genes regulated in response to depletion of Wolbachia by tetracycline, and genotyping of Wolbachia endosymbionts from different filarial worms.    

Jennifer Vollmer

Ph.D. candidate

Project: Wolbachia cell wall biosynthesis and structure of Wolbachia Lipid II using fluorescent and electron microscopy and biochemical assays.

Contact Information

Phone: +49-228-287-11510

Fax.:+49-228-287-11167

 

Collaborations

Drs. O. Adjei and A. Debrah

Kumasi Centre for Collaborative Research (KCCR) and Kwame Nkrumah University of Science and Technology, Kumasi, Ghana

Project: Monitoring depletion of Wolbachia from W. bancrofti and O. volvulus in patients enlisted in clinical trials of antiwolbachial drugs, and genotyping of single nucleotide polymorphisms of patients with lymphatic filariasis

Drs. M. Famulok and G. Mayer

Kekulé Institut for Organic Chemistry and Biochemistry

University of Bonn, Bonn, Germany

Project:  Aptamer technology and HTS facilities

Drs. B. Slatko and C. Carlow

New England Biolabs, Ipswich, MA, USA

Project: Identification of new antiwolbachial drugs by Aptamer screening and SELEX

Dr. H.G. Sahl

Institute for Medical Microbiology, Immunology and Parasitology

University Medical Center Bonn, Bonn, Germany

Project: Lipid II biosynthesis in the alpha-proteobacteria Wolbachia of filarial nematodes

Publications 

Albers A, Esum ME, Tendongfor N, Enyong P, Klarmann U, Wanji S, Hoerauf A, and Pfarr K (2012). Retarded Onchocerca volvulus L1 to L3 larval development in the Simulium damnosum vector after anti-wolbachial treatment of the human host. Parasit Vectors 5: 12.

Schiefer A, Schmitz A, Schäberle TF, Specht S, Lämmer C, et al. (2012) Corallopyronin A specifically targets and depletes essential obligate Wolbachia endobacteria from filarial nematodes in vivo. J Infect Dis in press.

Hoerauf A, Pfarr K, Mand S, Debrah AY, Specht S (2011) Filariasis in Africa-treatment challenges and prospects. Clin Microbiol Infect 17: 977-985.

Debrah AY, Mand S, Marfo-Debrekyei Y, Batsa L, Albers A, Specht S, Klarmann U, Pfarr K, Adjei O, Hoerauf A (2011) Macrofilaricidal Activity in Wuchereria bancrofti after 2 Weeks Treatment with a Combination of Rifampicin plus Doxycycline. J Parasitol Res 2011: 201617.

Debrah AY, Batsa L, Albers A, Mand S, Toliat MR, et al. (2011) Transforming Growth Factor-β 1 variant Leu10Pro is associated with both lack of microfilariae and differential microfilarial loads in the blood of people infected with lymphatic filariasis. Hum Immunol 72: 1143-1148.

Niebel B, Lentz C, Pofahl M, Mayer G, Hoerauf A, Pfarr KM, Famulok M (2010) ADLOC: an aptamer-displacement assay based on luminescent oxygen channeling. Chemistry 16: 11100-11107.

Pfarr KM, Debrah AY, Specht S, Hoerauf A (2009) Filariasis and lymphoedema. Parasite Immunol 31: 664-672.

Mand S, Pfarr K, Sahoo PK, Satapathy AK, Specht S, et al. (2009) Macrofilaricidal activity and amelioration of lymphatic pathology in bancroftian filariasis after 3 weeks of doxycycline followed by single-dose diethylcarbamazine. Am J Trop Med Hyg 81: 702-711.

Henrichfreise B, Schiefer A, Schneider T, Nzukou E, Poellinger C, Hoffmann TJ, Johnston KL, Moelleken K, Wiedemann I, Pfarr K, Hoerauf A, Sahl HG (2009) Functional conservation of the lipid II biosynthesis pathway in the cell wall-less bacteria Chlamydia and Wolbachia: why is lipid II needed? Mol Microbiol 73: 913-923.

Debrah AY, Mand S, Marfo-Debrekyei Y, Batsa L, Pfarr K, Lawson B, Taylor M, Adjei O, Hoerauf A (2009) Reduction in levels of plasma vascular endothelial growth factor-A and improvement in hydrocele patients by targeting endosymbiotic Wolbachia sp. in Wuchereria bancrofti with doxycycline. Am J Trop Med Hyg 80: 956-963.

Supali T, Djuardi Y, Pfarr KM, Wibowo H, Taylor MJ, Hoerauf A, Houwing-Duistermaat JJ, Yazdanbakhsh M, Sartono E (2008) Doxycycline treatment of Brugia malayi-infected persons reduces microfilaremia and adverse reactions after diethylcarbamazine and albendazole treatment. Clin Infect Dis 46: 1385-1393.

Pfarr KM, Heider U, Schmetz C, Buttner DW, Hoerauf A (2008) The mitochondrial heat shock protein 60 (HSP60) is up-regulated in Onchocerca volvulus after the depletion of Wolbachia. Parasitology 135: 529-538.

Hoerauf A, Specht S, Büttner M, Pfarr K, Mand S, Fimmers R, Marfo-Debrekyei Y, Konadu P, Debrah AY, Bandi C, Brattig N, Albers A, Larbi J, Batsa L, Adjei O, Büttner DW (2008) Wolbachia endobacteria depletion by doxycycline as antifilarial therapy has macrofilaricidal activity in onchocerciasis: a randomized placebo-controlled study. Med Microbiol Immunol 197: 295-311.

Arumugam S, Pfarr KM, Hoerauf A (2008) Infection of the intermediate mite host with Wolbachia-depleted Litomosoides sigmodontis microfilariae: Impaired L1 to L3 development and subsequent sex-ratio distortion in adult worms. Int J Parasitol 38: 981-987.

Pfarr KM, Hoerauf A (2007) A niche for Wolbachia. Trends Parasitol 23: 5-7.

Pfarr K, Foster J, Slatko B, Hoerauf A, Eisen JA (2007) On the taxonomic status of the intracellular bacterium Wolbachia pipientis: should this species name include the intracellular bacteria of filarial nematodes? Int J Syst Evol Microbiol 57: 1677-1678.

Pfarr K, Foster J, Slatko B (2007) It Takes Two: Lessons From the First Nematode Wolbachia Genome Sequence. In: Hoerauf A, Rao RU, editors. Wolbachia: A Bug's Life in another Bug. Basel: Karger. pp. 52-65.

Hoerauf A, Pfarr K (2007) Wolbachia endosymbionts: An Achilles' Heel of filarial nematodes. In: Hoerauf A, Rao RU, editors. Wolbachia: a bug's life in another bug. Basel: Karger. pp. 15-30.

Debrah AY, Mand S, Toliat MR, Marfo-Debrekyei Y, Batsa L, Nürnberg P, Lawson B, Adjei O, Hoerauf A, Pfarr K (2007) Plasma vascular endothelial growth factor-A (VEGF-A) and VEGF-A gene polymorphism are associated with hydrocele development in lymphatic filariasis. Am J Trop Med Hyg 77: 601-608.

Debrah AY, Mand S, Marfo-Debrekyei Y, Batsa L, Pfarr K, Büttner  M, Adjei O, Büttner  D, Hoerauf A (2007) Macrofilaricidal effect of 4 weeks of treatment with doxycycline on Wuchereria bancrofti. Trop Med Int Health 12: 1433-1441.

Turner JD, Mand S, Debrah AY, Muehlfeld J, Pfarr K, McGarry HF, Adjei O, Taylor MJ, Hoerauf A (2006) A randomized, double-blind clinical trial of a 3-week course of doxycycline plus albendazole and ivermectin for the treatment of Wuchereria bancrofti infection. Clin Infect Dis 42: 1081-1089.

Pfarr KM, Hoerauf AM (2006) Antibiotics which target the Wolbachia endosymbionts of filarial parasites: a new strategy for control of filariasis and amelioration of pathology. Mini Rev Med Chem 6: 203-210.

Pfarr K, Heider U, Hoerauf A (2006) RNAi mediated silencing of actin expression in adult Litomosoides sigmodontis is specific, persistent and results in a phenotype. Int J Parasitol 36: 661-669.

Heider U, Blaxter M, Hoerauf A, Pfarr KM (2006) Differential display of genes expressed in the filarial nematode Litomosoides sigmodontis reveals a putative phosphate permease up-regulated after depletion of Wolbachia endobacteria. Int J Med Microbiol 296: 287-299.

Debrah AY, Mand S, Specht S, Marfo-Debrekyei Y, Batsa L, Pfarr K, Larbi J, Lawson B, Taylor M, Adjei O, Hoerauf A (2006) Doxycycline reduces plasma VEGF-C/sVEGFR-3 and improves pathology in lymphatic filariasis. PLoS Pathog 2: e92.

Pfarr K, Hoerauf A (2005) The annotated genome of Wolbachia from the filarial nematode Brugia malayi: what it means for progress in antifilarial medicine. PLoS Med 2: e110.

Mand S, Marfo-Debrekyei Y, Debrah A, Büttner M, Batsa L, Pfarr K, Adjei O, Hoerauf A (2005) Frequent detection of worm movements in onchocercal nodules by ultrasonography. Filaria J 4: 1.

Gilbert J, Nfon CK, Makepeace BL, Njongmeta LM, Hastings IM, Pfarr KM, Renz A, Tanya VN, Trees AJ (2005) Antibiotic chemotherapy of onchocerciasis: in a bovine model, killing of adult parasites requires a sustained depletion of endosymbiotic bacteria (Wolbachia species). J Infect Dis 192: 1483-1493.

Pfarr KM, Fischer K, Hoerauf A (2003) Involvement of Toll-like receptor 4 in the embryogenesis of the rodent filaria Litomosoides sigmodontis. Med Microbiol Immunol (Berl) 192: 53-56.

McGarry HF, Pfarr K, Egerton G, Hoerauf A, Akue JP, Enyong P, Wanji S, Klager SL, Bianco AE, Beeching NJ, Taylor MJ (2003) Evidence against Wolbachia symbiosis in Loa loa. Filaria J 2: 9.

Hoerauf A, Mand S, Fischer K, Kruppa T, Marfo-Debrekyei Y, Debrah AY, Pfarr KM, Adjei O, Büttner DW (2003) Doxycycline as a novel strategy against bancroftian filariasis-depletion of Wolbachia endosymbionts from Wuchereria bancrofti and stop of microfilariae production. Med Microbiol Immunol (Berl) 5: 261-273.

Pfarr KM, Qazi S, Fuhrman JA (2001) Nitric oxide synthase in filariae: demonstration of nitric oxide production by embryos in Brugia malayi and Acanthocheilonema viteae. Exp Parasitol 97: 205-214.

Pfarr KM, Fuhrman JA (2000) Brugia malayi: localization of nitric oxide synthase in a lymphatic filariid. Exp Parasitol 94: 92-98.

Soltysik-Espanola M, Klinzing DC, Pfarr K, Burke RD, Ernst SG (1994) Endo16, a large multidomain protein found on the surface and ECM of endodermal cells during sea urchin gastrulation, binds calcium. Dev Biol 165: 73-85.

Date: 
Monday, July 4, 2011 - 12:00 - Monday, December 31, 2012 - 12:00

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