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Foss MH, Pou S, Davidson PM, Dunaj JL, Winter RW, Pou S, Licon MH, Doh JK, Li Y, Kelly JX, Dodean RA, Koop DR, Riscoe MK, Purdy GE. Diphenylether-Modified 1,2-Diamines with Improved Drug Properties for Development against Mycobacterium tuberculosis. ACS Infect Dis 2016; 2:500-8. [PMID: 27626102 DOI: 10.1021/acsinfecdis.6b00052] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
New treatments for tuberculosis infection are critical to combat the emergence of multidrug- and extensively drug-resistant Mycobacterium tuberculosis (Mtb). We report the characterization of a diphenylether-modified adamantyl 1,2-diamine that we refer to as TBL-140, which has a minimal inhibitory concentration (MIC99) of 1.2 μg/mL. TBL-140 is effective against drug-resistant Mtb and nonreplicating bacteria. In addition, TBL-140 eliminates expansion of Mtb in cell culture infection assays at its MIC. To define the mechanism of action of this compound, we performed a spontaneous mutant screen and biochemical assays. We determined that TBL-140 treatment affects the proton motive force (PMF) by perturbing the transmembrane potential (ΔΨ), consistent with a target in the electron transport chain (ETC). As a result, treated bacteria have reduced intracellular ATP levels. We show that TBL-140 exhibits greater metabolic stability than SQ109, a structurally similar compound in clinical trials for treatment of MDR-TB infections. Combined, these results suggest that TBL-140 should be investigated further to assess its potential as an improved therapeutic lead against Mtb.
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Affiliation(s)
- Marie H. Foss
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Sovitj Pou
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Patrick M. Davidson
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Jennifer L. Dunaj
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Rolf W. Winter
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Sovijja Pou
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Meredith H. Licon
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Julia K. Doh
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Yuexin Li
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Jane X. Kelly
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Rozalia A. Dodean
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Dennis R. Koop
- Department of Physiology and Pharmacology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Michael K. Riscoe
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
- Portland VA Medical Center, 3710 S.W. U.S. Veterans Hospital
Road, Portland, Oregon 97239, United States
| | - Georgiana E. Purdy
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, Oregon 97239, United States
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Chou TH, Delmar JA, Wright CC, Kumar N, Radhakrishnan A, Doh JK, Licon MH, Bolla JR, Lei HT, Rajashankar KR, Su CC, Purdy GE, Yu EW. Crystal structure of the Mycobacterium tuberculosis transcriptional regulator Rv0302. Protein Sci 2015; 24:1942-55. [PMID: 26362239 DOI: 10.1002/pro.2802] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/08/2015] [Accepted: 09/11/2015] [Indexed: 11/10/2022]
Abstract
Mycobacterium tuberculosis is a pathogenic bacterial species, which is neither Gram positive nor Gram negative. It has a unique cell wall, making it difficult to kill and conferring resistance to antibiotics that disrupt cell wall biosynthesis. Thus, the mycobacterial cell wall is critical to the virulence of these pathogens. Recent work shows that the mycobacterial membrane protein large (MmpL) family of transporters contributes to cell wall biosynthesis by exporting fatty acids and lipidic elements of the cell wall. The expression of the Mycobacterium tuberculosis MmpL proteins is controlled by a complicated regulatory network system. Here we report crystallographic structures of two forms of the TetR-family transcriptional regulator Rv0302, which participates in regulating the expression of MmpL proteins. The structures reveal a dimeric, two-domain molecule with architecture consistent with the TetR family of regulators. Comparison of the two Rv0302 crystal structures suggests that the conformational changes leading to derepression may be due to a rigid body rotational motion within the dimer interface of the regulator. Using fluorescence polarization and electrophoretic mobility shift assays, we demonstrate the recognition of promoter and intragenic regions of multiple mmpL genes by this protein. In addition, our isothermal titration calorimetry and electrophoretic mobility shift experiments indicate that fatty acids may be the natural ligand of this regulator. Taken together, these experiments provide new perspectives on the regulation of the MmpL family of transporters.
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Affiliation(s)
- Tsung-Han Chou
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011
| | - Jared A Delmar
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011
| | - Catherine C Wright
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, 97239
| | - Nitin Kumar
- Department of Chemistry, Iowa State University, Ames, Iowa, 50011
| | | | - Julia K Doh
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, 97239
| | - Meredith H Licon
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, 97239
| | - Jani Reddy Bolla
- Department of Chemistry, Iowa State University, Ames, Iowa, 50011
| | - Hsiang-Ting Lei
- Department of Chemistry, Iowa State University, Ames, Iowa, 50011
| | - Kanagalaghatta R Rajashankar
- NE-CAT and Department of Chemistry and Chemical Biology, Argonne National Laboratory, Cornell University, Argonne, Illinois, 60439
| | - Chih-Chia Su
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011
| | - Georgiana E Purdy
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, 97239
| | - Edward W Yu
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011.,Department of Chemistry, Iowa State University, Ames, Iowa, 50011
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Delmar JA, Chou TH, Wright CC, Licon MH, Doh JK, Radhakrishnan A, Kumar N, Lei HT, Bolla JR, Rajashankar KR, Su CC, Purdy GE, Yu EW. Structural Basis for the Regulation of the MmpL Transporters of Mycobacterium tuberculosis. J Biol Chem 2015; 290:28559-28574. [PMID: 26396194 DOI: 10.1074/jbc.m115.683797] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Indexed: 11/06/2022] Open
Abstract
The mycobacterial cell wall is critical to the virulence of these pathogens. Recent work shows that the MmpL (mycobacterial membrane protein large) family of transporters contributes to cell wall biosynthesis by exporting fatty acids and lipidic elements of the cell wall. The expression of the Mycobacterium tuberculosis MmpL proteins is controlled by a complex regulatory network, including the TetR family transcriptional regulators Rv3249c and Rv1816. Here we report the crystal structures of these two regulators, revealing dimeric, two-domain molecules with architecture consistent with the TetR family of regulators. Buried extensively within the C-terminal regulatory domains of Rv3249c and Rv1816, we found fortuitous bound ligands, which were identified as palmitic acid (a fatty acid) and isopropyl laurate (a fatty acid ester), respectively. Our results suggest that fatty acids may be the natural ligands of these regulatory proteins. Using fluorescence polarization and electrophoretic mobility shift assays, we demonstrate the recognition of promoter and intragenic regions of multiple mmpL genes by these proteins. Binding of palmitic acid renders these regulators incapable of interacting with their respective operator DNAs, which will result in derepression of the corresponding mmpL genes. Taken together, these experiments provide new perspectives on the regulation of the MmpL family of transporters.
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Affiliation(s)
- Jared A Delmar
- Departments of Physics and Astronomy, Iowa State University, Ames, Iowa 50011
| | - Tsung-Han Chou
- Departments of Physics and Astronomy, Iowa State University, Ames, Iowa 50011
| | - Catherine C Wright
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon 97239
| | - Meredith H Licon
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon 97239
| | - Julia K Doh
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon 97239
| | | | - Nitin Kumar
- Departments of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Hsiang-Ting Lei
- Departments of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Jani Reddy Bolla
- Departments of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Kanagalaghatta R Rajashankar
- Northeastern Collaborative Access Team and Department of Chemistry and Chemical Biology, Cornell University, Argonne National Laboratory, Argonne, Illinois 60439
| | - Chih-Chia Su
- Departments of Physics and Astronomy, Iowa State University, Ames, Iowa 50011
| | - Georgiana E Purdy
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon 97239
| | - Edward W Yu
- Departments of Physics and Astronomy, Iowa State University, Ames, Iowa 50011; Departments of Chemistry, Iowa State University, Ames, Iowa 50011.
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Herrera CP, Licon MH, Nation CS, Jameson SB, Wesson DM. Genotype diversity of Trypanosoma cruzi in small rodents and Triatoma sanguisuga from a rural area in New Orleans, Louisiana. Parasit Vectors 2015; 8:123. [PMID: 25890064 PMCID: PMC4344744 DOI: 10.1186/s13071-015-0730-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 02/12/2015] [Indexed: 12/18/2022] Open
Abstract
Background Chagas disease is an anthropozoonosis caused by the protozoan parasite Trypanosoma cruzi that represents a major public health problem in Latin America. Although the United States is defined as non-endemic for Chagas disease due to the rarity of human cases, the presence of T. cruzi has now been amply demonstrated as enzootic in different regions of the south of the country from Georgia to California. In southeastern Louisiana, a high T. cruzi infection rate has been demonstrated in Triatoma sanguisuga, the local vector in this area. However, little is known about the role of small mammals in the wild and peridomestic transmission cycles. Methods This study focused on the molecular identification and genotyping of T. cruzi in both small rodents and T. sanguisuga from a rural area of New Orleans, Louisiana. DNA extractions were prepared from rodent heart, liver, spleen and skeletal muscle tissues and from cultures established from vector feces. T. cruzi infection was determined by standard PCR using primers specific for the minicircle variable region of the kinetoplastid DNA (kDNA) and the highly repetitive genomic satellite DNA (satDNA). Genotyping of discrete typing units (DTUs) was performed by amplification of mini-exon and 18S and 24Sα rRNA genes and subsequent sequence analysis. Results The DTUs TcI, TcIV and, for the first time, TcII, were identified in tissues of mice and rats naturally infected with T. cruzi captured in an area of New Orleans, close to the house where the first human case of Chagas disease was reported in Louisiana. The T. cruzi infection rate in 59 captured rodents was 76%. The frequencies of the detected DTUs in such mammals were TcI 82%, TcII 22% and TcIV 9%; 13% of all infections contained more than one DTU. Conclusions Our results indicate a probable presence of a considerably greater diversity in T. cruzi DTUs circulating in the southeastern United States than previously reported. Understanding T. cruzi transmission dynamics in sylvatic and peridomestic cycles in mammals and insect vectors will be crucial to estimating the risk of local, vector-borne transmission of T. cruzi to humans in the United States.
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Affiliation(s)
- Claudia P Herrera
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, Rm. 1824, New Orleans, LA, 70112, USA.
| | - Meredith H Licon
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, Rm. 1824, New Orleans, LA, 70112, USA.
| | - Catherine S Nation
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, Rm. 1824, New Orleans, LA, 70112, USA.
| | - Samuel B Jameson
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, Rm. 1824, New Orleans, LA, 70112, USA.
| | - Dawn M Wesson
- Department of Tropical Medicine, Vector-Borne Infectious Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, 1440 Canal Street, Rm. 1824, New Orleans, LA, 70112, USA.
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