| 1. |
- Grønberg, Christina, et al.
(författare)
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Structure and ion-release mechanism of P IB-4-type ATPases
- 2022
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Ingår i: eLife. - : eLife Sciences Publications Ltd. - 2050-084X.
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Transition metals, such as zinc, are essential micronutrients in all organisms, but alsohighly toxic in excessive amounts. Heavy-metal transporting P-type (PIB) ATPases are crucial forhomeostasis, conferring cellular detoxification and redistribution through transport of these ionsacross cellular membranes. No structural information is available for the PIB-4-ATPases, the subclasswith the broadest cargo scope, and hence even their topology remains elusive. Here, we presentstructures and complementary functional analyses of an archetypal PIB-4-ATPase, sCoaT fromSulfitobacter sp. NAS14-1. The data disclose the architecture, devoid of classical so-called heavy-metal-binding domains (HMBDs), and provide fundamentally new insights into the mechanism anddiversity of heavy-metal transporters. We reveal several novel P-type ATPase features, includinga dual role in heavy-metal release and as an internal counter ion of an invariant histidine. We alsoestablish that the turnover of PIB-ATPases is potassium independent, contrasting to many otherP-type ATPases. Combined with new inhibitory compounds, our results open up for efforts in forexample drug discovery, since PIB-4-ATPases function as virulence factors in many pathogens.
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| 2. |
- Rao, Komal Umashankar, et al.
(författare)
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A broad spectrum anti-bacterial peptide with an adjunct potential for tuberculosis chemotherapy
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Alternative ways to prevent and treat infectious diseases are needed. Previously, we identified a fungal peptide, NZX, that was comparable to rifampicin in lowering M. tuberculosis load in a murine tuberculosis (TB) infection model. Here we assessed the potential synergy between this cationic host defence peptide (CHDP) and the current TB drugs and analysed its pharmacokinetics. We found additive effect of this peptide with isoniazid and ethambutol and confirmed these results with ethambutol in a murine TB-model. In vivo, the peptide remained stable in circulation and preserved lung structure better than ethambutol alone. Antibiotic resistance studies did not induce mutants with reduced susceptibility to the peptide. We further observed that this peptide was effective against nontuberculous mycobacteria (NTM), such as M. avium and M. abscessus, and several Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus. In conclusion, the presented data supports a role for this CHDP in the treatment of drug resistant organisms.
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| 3. |
- Rao, Komal Umashankar, et al.
(författare)
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Mechanisms of a Mycobacterium tuberculosis Active Peptide
- 2023
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Ingår i: Pharmaceutics. - : MDPI AG. - 1999-4923. ; 15:2
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Tidskriftsartikel (refereegranskat)abstract
- Multidrug-resistant tuberculosis (MDR) continues to pose a threat to public health. Previously, we identified a cationic host defense peptide with activity against Mycobacterium tuberculosis in vivo and with a bactericidal effect against MDR M. tuberculosis at therapeutic concentrations. To understand the mechanisms of this peptide, we investigated its interactions with live M. tuberculosis and liposomes as a model. Peptide interactions with M. tuberculosis inner membranes induced tube-shaped membranous structures and massive vesicle formation, thus leading to bubbling cell death and ghost cell formation. Liposomal studies revealed that peptide insertion into inner membranes induced changes in the peptides’ secondary structure and that the membranes were pulled such that they aggregated without permeabilization, suggesting that the peptide has a strong inner membrane affinity. Finally, the peptide targeted essential proteins in M. tuberculosis, such as 60 kDa chaperonins and elongation factor Tu, that are involved in mycolic acid synthesis and protein folding, which had an impact on bacterial proliferation. The observed multifaceted targeting provides additional support for the therapeutic potential of this peptide.
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| 4. |
- Tenland, Erik, et al.
(författare)
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Effective delivery of the anti-mycobacterial peptide NZX in mesoporous silica nanoparticles
- 2019
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Background Intracellular delivery of antimicrobial agents by nanoparticles, such as mesoporous silica particles (MSPs), offers an interesting strategy to treat intracellular infections. In tuberculosis (TB), Mycobacterium tuberculosis avoids components of the immune system by residing primarily inside alveolar macrophages, which are the desired target for TB therapy. Methods and findings We have previously identified a peptide, called NZX, capable of inhibiting both clinical and multi-drug resistant strains of M. tuberculosis at therapeutic concentrations. In this study we analysed the potential of MSPs containing NZX for the treatment of tuberculosis. The MSPs released functional NZX gradually into simulated lung fluid and the peptide filled MSPs were easily taken up by primary macrophages. In an intracellular infection model, the peptide containing particles showed increased mycobacterial killing compared to free peptide. The therapeutic potential of peptide containing MSPs was investigated in a murine infection model, showing that MSPs preserved the effect to eliminate M. tuberculosis in vivo. Conclusions In this study we found that loading the antimicrobial peptide NZX into MSPs increased the inhibition of intracellular mycobacteria in primary macrophages and preserved the ability to eliminate M. tuberculosis in vivo in a murine model. Our studies provide evidence for the feasibility of using MSPs for treatment of tuberculosis.
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| 5. |
- Umashankar Rao, Komal
(författare)
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Antimicrobial peptide therapy for tuberculosis infections
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tuberculosis is a communicable disease that persists as a second leading cause for death, by an infectious agent. Several reasons contribute to this issue to this, of which an upsurge in antibiotic resistance is of top concern. Resistance patterns in the form of mono or multidrug resistance was reported to most clinical therapies at our disposal. This thesis aims to address this issue by studying a novel antimicrobial peptide named NZX as a potential drug candidate in the tuberculosis treatment regimen. Mycobacterium tuberculosis, the tuberculosis pathogen is made up of a unique cell wall that renders it resistant to most compounds tested. We set out to identify the membrane interactive potential of NZX using artificial liposomes and live bacteria. The peptide appeared to interact with inner membrane of live mycobacteria by a pull and aggregate mechanism, eventually disrupting the cell integrity. A similar aggregation pattern was observed for liposomes as well as insertion into the membrane core was demonstrated. Antimicrobial peptides are known to possess multiactivity mode of mechanism. To understand this, we investigated internal targets through a proteomics study. This led to the identification of essential protein targets such as chaperonins 60 kDa and elongation factor EF-Tu involved in bacterial growth and maintenance. Together, these findings displayed NZX’s multifaceted activity against mycobacteria. The lack of mutants from resistance development studies for NZX could be asserted to their multiactivity feature. Evidence of the therapeutic potential of NZX as an antimicrobial agent was explored. NZX displayed a wide range of activity when tested against a few clinically isolated nontuberculosis mycobacteria species and drug-resistant Staphylococcus aureus. The effect of drug-to-drug interactions were observed from an in vivo and in vitro standpoint and the peptide portrayed an additive effect with ethambutol, however, remained indifferent with other drug combinations. NZX retained its stability and antimicrobial property despite exposure to proteolytic molecules and human serum respectively. Directed therapy of NZX was performed by loading NZX onto nanoparticles and was found to be effectual for intracellular therapy. Moreover, nanoparticle loaded NZX exhibited better antimicrobial activity in primary macrophages. The data presented here shows cumulative evidence on NZX as a prospective candidate against mycobacterial infections.
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| 6. |
- Umashankar Rao, Komal, et al.
(författare)
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Isolation and Purification of Mycobacterial Extracellular Vesicles
- 2023. - 2nd
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Ingår i: Bacterial Pathogenesis. - 1064-3745 .- 1940-6029. - 9781071632420 - 9781071632437 ; 2674, s. 55-60
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Bokkapitel (refereegranskat)abstract
- Bacterial extracellular vesicles (EVs) contain numerous active substances that mediate bacterial interactions with their host and with other microbes. Best defined are the EVs from Gram-negative bacteria that have been shown to deliver virulence factors, modulate the immune responses, mediate antibiotic resistance, and also inhibit competitive microbes. Due to the complex cell wall structures of Gram-positive bacteria and mycobacteria, EVs from these bacteria were only recently reported. This protocol describes the isolation of EVs from mycobacteria.
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