Sansanmycin natural product analogues as potent and selective anti-mycobacterials that inhibit lipid I biosynthesis.

Tuberculosis (TB) is responsible for enormous global morbidity and mortality, and current treatment regimens rely on the use of drugs that have been in use for more than 40 years. Owing to widespread resistance to these therapies, new drugs are desperately needed to control the TB disease burden. Herein, we describe the rapid synthesis of analogues of the sansanmycin uridylpeptide natural products that represent promising new TB drug leads. The compounds exhibit potent and selective inhibition of Mycobacterium tuberculosis, the etiological agent of TB, both in vitro and intracellularly. The natural product analogues were also shown to be nanomolar inhibitors of Mtb phospho-MurNAc-pentapeptide translocase, the enzyme responsible for the synthesis of lipid I in mycobacteria. This work lays the foundation for the development of uridylpeptide natural product analogues as new TB drug candidates that operate through the inhibition of peptidoglycan biosynthesis

Characterization of MenA (isoprenyl diphosphate:1,4-dihydroxy-2-naphthoate isoprenyltransferase) from Mycobacterium tuberculosis.

The menaquinone biosynthetic pathway presents a promising drug target against Mycobacterium tuberculosis and potentially other Gram-positive pathogens. In the present study, the essentiality, steady state kinetics of MenA from M. tuberculosis and the mechanism of MenA inhibition by Ro 48-8071 were characterized. MenA [isoprenyl diphosphate:1,4-dihydroxy-2-naphthoate (DHNA) isoprenyltransferase] catalyzes a critical reaction in menaquinone biosynthesis that involves the conversion of cytosolic DHNA, to membrane bound demethylmenaquinone by transferring a hydrophobic 45-carbon isoprenoid chain (in the case of mycobacteria) to the ring nucleus of DHNA. Rv0534c previously identified as the gene encoding MenA in M. tuberculosis complemented a menA deletion in E. coli and an E. coli host expressing Rv0534c exhibited an eight-fold increase in MenA specific activity over the control strain harboring empty vector under similar assay conditions. Expression of Rv0534c is essential for mycobacterial survival and the native enzyme from M. tuberculosis H37Rv was characterized using membrane preparations as it was not possible to solubilize and purify the recombinant enzyme. The enzyme is absolutely dependent on the presence of a divalent cation for optimal activity with Mg+2 being the most effective and is active over a wide pH range, with pH 8.5 being optimal. The apparent Km values for DHNA and farnesyl diphosphate were found to be 8.2 and 4.3 μM, respectively. Ro 48-8071, a compound previously reported to inhibit mycobacterial MenA activity, is non-competitive with regard to DHNA and competitive with regard to the isoprenyldiphosphate substrate

The essential role of cholesterol metabolism in the intracellular survival of Mycobacterium 2 leprae is not coupled to central carbon metabolism and energy production

Submitted by sandra infurna ([email protected]) on 2016-05-17T16:02:04Z No. of bitstreams: 1 mariaangela_marques_etal_IOC_2015.pdf: 1511352 bytes, checksum: 4396e5f1e7be4b619876fe93a31f911a (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-05-17T16:50:23Z (GMT) No. of bitstreams: 1 mariaangela_marques_etal_IOC_2015.pdf: 1511352 bytes, checksum: 4396e5f1e7be4b619876fe93a31f911a (MD5)Made available in DSpace on 2016-05-17T16:50:23Z (GMT). No. of bitstreams: 1 mariaangela_marques_etal_IOC_2015.pdf: 1511352 bytes, checksum: 4396e5f1e7be4b619876fe93a31f911a (MD5) Previous issue date: 2015Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Microbiologia Celular. Rio de Janeiro, RJ, Brasil / Colorado State University. Department of Microbiology, Immunology and Pathology. Fort Collins, CO, USA.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Microbiologia Celular. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Microbiologia Celular. Rio de Janeiro, RJ, BrasilColorado State University. Department of Microbiology, Immunology and Pathology. Fort Collins, CO, USAFundação Oswaldo Cruz.de Microbiologia Celular. Rio de Janeiro, RJ, Brasil Instituto Oswaldo Cruz. LaboratórioFundação Oswaldo Cruz.de Microbiologia Celular. Rio de Janeiro, RJ, Brasil Instituto Oswaldo Cruz. LaboratórioColorado State University. Department of Microbiology, Immunology and Pathology. Fort Collins, CO, USAFundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Genômica Funcional e Bioinformática. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Bioquímica Médica. Laboratório de Bioquímica de Lipídeos e Lipoproteínas. Rio de Janeiro, RJ, Brasil.Colorado State University. Department of Microbiology, Immunology and Pathology. Fort Collins, CO, USAColorado State University. Department of Microbiology, Immunology and Pathology. Fort Collins, CO, USAColorado State University. Department of Microbiology, Immunology and Pathology. Fort Collins, CO, USAColorado State University. Department of Microbiology, Immunology and Pathology. Fort Collins, CO, USAFundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Microbiologia Celular. Rio de Janeiro, RJ, Brasil.Mycobacterium leprae induces the formation of lipid droplets, which are recruited to pathogen-containing phagosomes in infected macrophages and Schwann cells. Cholesterol is among the lipids with increased abundance in M. leprae-infected cells, and intracellular survival relies on cholesterol accumulation. The present study investigated the capacity of M. leprae to acquire and metabolize cholesterol. In silico analyses showed that oxidation of cholesterol to cholest-4-en-3-one (cholestenone), the first step of cholesterol degradation catalyzed by the enzyme 3β-hydroxysteroid dehydrogenase (3β-HSD), is apparently the only portion of the cholesterol catabolic pathway seen in Mycobacterium tuberculosis preserved by M. leprae. Incubation of bacteria with radiolabeled cholesterol confirmed the in silico predictions. Radiorespirometry and lipid analyses performed after incubating M. leprae with [4-(14)C]cholesterol or [26-(14)C]cholesterol showed the inability of this pathogen to metabolize the sterol rings or the side chain of cholesterol as a source of energy and carbon. However, the bacteria avidly incorporated cholesterol and, as expected, converted it to cholestenone both in vitro and in vivo. Our data indicate that M. leprae has lost the capacity to degrade and utilize cholesterol as a nutritional source but retains the enzyme responsible for its oxidation to cholestenone. Thus, the essential role of cholesterol metabolism in the intracellular survival of M. leprae is uncoupled from central carbon metabolism and energy production. Further elucidation of cholesterol metabolism in the host cell during M. leprae infection will establish the mechanism by which this lipid supports M. leprae intracellular survival and will open new avenues for novel leprosy therapies. Our study focused on the obligate intracellular pathogen Mycobacterium leprae and its capacity to metabolize cholesterol. The data make an important contribution for those interested in understanding the mechanisms of mycobacterial pathogenesis, since they indicate that the essential role of cholesterol for M. leprae intracellular survival does not rely on its utilization as a nutritional source. Our findings reinforce the complexity of cholesterol's role in sustaining M. leprae infection. Further elucidation of cholesterol metabolism in the host cell during M. leprae infection will establish the mechanism by which this lipid supports M. leprae intracellular survival and will open new avenues for novel leprosy therapies

Synthetic sansanmycin analogues as potent mycobacterium tuberculosis translocase I inhibitors

Herein, we report the design and synthesis of inhibitors of Mycobacterium tuberculosis (Mtb) phospho-MurNAc-pentapeptide translocase I (MurX), the first membrane-associated step of peptidoglycan synthesis, leveraging the privileged structure of the sansanmycin family of uridylpeptide natural products. A number of analogues bearing hydrophobic amide modifications to the pseudo-peptidic end of the natural product scaffold were generated that exhibited nanomolar inhibitory activity against Mtb MurX and potent activity against Mtb in vitro. We show that a lead analogue bearing an appended neopentylamide moiety possesses rapid antimycobacterial effects with a profile similar to the frontline tuberculosis drug isoniazid. This molecule was also capable of inhibiting Mtb growth in macrophages where mycobacteria reside in vivo and reduced mycobacterial burden in an in vivo zebrafish model of tuberculosis

Multitarget Drug Discovery for Tuberculosis and Other Infectious Diseases

We report the discovery of a series of new drug leads that have potent activity against Mycobacterium tuberculosis as well as against other bacteria, fungi, and a malaria parasite. The compounds are analogues of the new tuberculosis (TB) drug SQ109 (1), which has been reported to act by inhibiting a transporter called MmpL3, involved in cell wall biosynthesis. We show that 1 and the new compounds also target enzymes involved in menaquinone biosynthesis and electron transport, inhibiting respiration and ATP biosynthesis, and are uncouplers, collapsing the pH gradient and membrane potential used to power transporters. The result of such multitarget inhibition is potent inhibition of TB cell growth, as well as very low rates of spontaneous drug resistance. Several targets are absent in humans but are present in other bacteria, as well as in malaria parasites, whose growth is also inhibited