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1.
Neurooncol Adv ; 4(1): vdac147, 2022.
Article in English | MEDLINE | ID: mdl-36212741

ABSTRACT

Background: The median survival of Glioblastoma multiforme (GBM) patients is 14+ months due to poor responses to surgery and chemoradiation. Means to counteract radiation resistance are therefore highly desirable. We demonstrate the membrane bound matrix metalloproteinase MT1-MMP promotes resistance of GBM to radiation, and that using a selective and brain permeable MT1-MMP inhibitor, (R)-ND336, improved tumor control can be achieved in preclinical studies. Methods: Public microarray and RNA-sequencing data were used to determine MT1-MMP relevance in GBM patient survival. Glioma stem-like neurospheres (GSCs) were used for both in vitro and in vivo assays. An affinity resin coupled with proteomics was used to quantify active MT1-MMP in brain tissue of GBM patients. Short hairpin RNA (shRNA)-mediated knockdown of MT1-MMP and inhibition via the MT1-MMP inhibitor (R)-ND336, were used to assess the role of MT1-MMP in radio-resistance. Results: MT1-MMP expression inversely correlated with patient survival. Active MT1-MMP was present in brain tissue of GBM patients but not in normal brain. shRNA- or (R)-ND336-mediated inhibition of MT1-MMP sensitized GSCs to radiation leading to a significant increase in survival of tumor-bearing animals. MT1-MMP depletion reduced invasion via the effector protease MMP2; and increased the cytotoxic response to radiation via induction of replication fork stress and accumulation of double strand breaks (DSBs), making cells more susceptible to genotoxic insult. Conclusions: MT1-MMP is pivotal in maintaining replication fork stability. Disruption of MT1-MMP sensitizes cells to radiation and can counteract invasion. (R)-ND336, which efficiently penetrates the brain, is therefore a novel radio-sensitizer in GBM.

2.
ACS Pharmacol Transl Sci ; 5(8): 555-561, 2022 Aug 12.
Article in English | MEDLINE | ID: mdl-35983271

ABSTRACT

There exists a paucity of information on the pathogenesis of pterygium, a benign ocular tumor that scars the cornea and can lead to vision loss. The main recourse for pterygium is surgery; however, recurrence is observed. Matrix metalloproteinases (MMPs) are involved in the pathology of pterygium. The determination of the specific MMP involved among the 24 human enzymes has not been established due to challenges in MMP profiling. We used an affinity resin that binds specifically to the active forms of MMPs in the complex mixture of the cellular proteome. The proteomics analysis identified active MMP-14 and three related metalloproteinases, ADAM9, ADAM10, and ADAM17, in human pterygia. Inhibition of MMP-14 with the small-molecule inhibitor (R)-ND-336 was assessed in cell migration and collagen contraction assays. (R)-ND-336 attenuated human conjunctiva fibroblast migration and mitigated collagen contraction, both activities required for the formation of pterygium. (R)-ND-336 holds the promise of a therapeutic recourse for pterygium as an orphan disease.

3.
ACS Pharmacol Transl Sci ; 5(8): 548-554, 2022 Aug 12.
Article in English | MEDLINE | ID: mdl-35983283

ABSTRACT

Idiopathic pulmonary fibrosis (IPF), a fatal disease characterized by excessive matrix degradation and fibrosis, destroys the lung architecture and results in the inability of the lungs to absorb oxygen. The cause(s) of IPF is unknown and current treatments are palliative. Matrix metalloproteinases (MMPs) and A Disintegrin And Metalloproteinases (ADAMs) likely play roles in IPF progression. However, specific MMPs and ADAMs in IPF have not been identified due to challenges in MMP/ADAM profiling. We employed a designer affinity resin that binds exclusively to the active forms of MMPs and ADAMs and found by mass spectrometry higher levels of active MMP-1, ADAM9, ADAM10, and ADAM17 in lung tissues of IPF patients. Inhibition of MMP-1 and ADAM10 with the small-molecule inhibitor GI254023X in an in vitro lung fibrosis assay decreased the profibrotic protein α-smooth muscle actin (α-SMA). Our results indicate that inhibition of MMP-1 and ADAM10 may hold promise in treatment of IPF.

4.
ACS Chem Biol ; 17(6): 1357-1363, 2022 06 17.
Article in English | MEDLINE | ID: mdl-35670779

ABSTRACT

Pressure ulcers (PUs) are chronic wounds that lead to amputations and death. Little is known about why PUs are recalcitrant to healing. Wound healing is mediated by matrix metalloproteinases (MMPs). The 24 MMPs in humans each exist in three forms, of which only one is catalytically competent. We analyzed human PU samples using an affinity resin that exclusively binds to the catalytically competent MMPs. We identified by mass spectrometry the active forms of MMP-1, MMP-8, MMP-9, and MMP-14. Concentrations of MMP-8, MMP-9, and MMP-14 were higher in human PUs compared to the healthy tissue, whereas those for MMP-1 did not change. Decreasing levels of active MMP-9 as the PU improved argued for a detrimental role for this enzyme. In a mouse model of PUs, a highly selective inhibitor for MMP-9 and MMP-14, (R)-ND-336, accelerated wound closure in parallel with significant amelioration of ulcer stage. (R)-ND-336 holds promise as a first-in-class treatment for PUs.


Subject(s)
Pressure Ulcer , Animals , Matrix Metalloproteinase 1 , Matrix Metalloproteinase 14 , Matrix Metalloproteinase 8/metabolism , Matrix Metalloproteinase 9/metabolism , Methylamines , Mice , Pressure Ulcer/drug therapy , Proteomics , Sulfides , Suppuration
5.
ACS Infect Dis ; 6(4): 703-714, 2020 04 10.
Article in English | MEDLINE | ID: mdl-32058691

ABSTRACT

The role of molecular arrangement of hydrophobic and hydrophilic groups for designing membrane-active molecules remains largely ambiguous. To explore this aspect, herein we report a series of membrane-active small molecules by varying the spatial distribution of hydrophobic groups. The two terminal amino groups of linear triamines such as diethylene triamine, bis(trimethylene)triamine, and bis(hexamethylene)triamine were conjugated with cationic amino acids bearing variable side chain hydrophobicity (such as diaminobutyric acid, ornithine, and lysine). The hydrophobicity was also modulated through conjugation of different long chain fatty acids with the central secondary amino group of the triamine. Molecules with constant backbone hydrophobicity displayed an enhanced antibacterial activity and decreased hemolytic activity upon increasing the side chain hydrophobicity of amino acids. On the other hand, increased hydrophobicity in the backbone introduced a slight hemolytic activity but a higher increment in antibacterial activity, resulting in better selective antibacterial compounds. The optimized lead compound derived from structure-activity-relationship (SAR) studies was the dodecanoyl analogue of a lysine series of compounds consisting of bis(hexamethylene)triamine as the backbone. This compound was active against various Gram-positive and Gram-negative bacteria at a low concentration (MIC ranged between 3.1 and 6.3 µg/mL) and displayed low toxicity toward mammalian cells (HC50 = 890 µg/mL and EC50 against HEK = 85 µg/mL). Additionally, it was able to kill metabolically inactive bacterial cells and eradicate preformed biofilms of MRSA. This compound showed excellent activity in a mouse model of skin infection with reduction of ∼4 log MRSA burden at 40 mg/kg dose without any sign of skin toxicity even at 200 mg/kg. More importantly, it revealed potent efficacy in an ex vivo model of human skin infection (with reduction of 85% MRSA burden at 50 µg/mL), which indicates great potential of the compound as an antibacterial agent to treat skin infections.


Subject(s)
Anti-Bacterial Agents/pharmacology , Biofilms/drug effects , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Hydrophobic and Hydrophilic Interactions , Skin Diseases, Bacterial/drug therapy , Small Molecule Libraries/chemistry , Amino Acids/chemistry , Animals , Anti-Bacterial Agents/chemistry , Female , HEK293 Cells , Humans , Methicillin-Resistant Staphylococcus aureus/drug effects , Mice, Inbred BALB C , Microbial Sensitivity Tests , Staphylococcal Infections/drug therapy , Staphylococcal Infections/microbiology , Structure-Activity Relationship
6.
Chem Commun (Camb) ; 56(14): 2147-2150, 2020 Feb 18.
Article in English | MEDLINE | ID: mdl-31970367

ABSTRACT

Cyclam-based antibacterial molecules (CAMs) that display potent activity against both the planktonic and stationary phase of multidrug-resistant Gram-negative bacteria were rationally designed. The optimized compound retained its activity in human plasma and eradicated preformed biofilms. It also revealed excellent potency in an ex vivo model of human corneal infections with negligible propensity of resistance development. This indicated the potential of this class of compound as a future antibacterial agent to tackle human corneal infections.


Subject(s)
Anti-Bacterial Agents/pharmacology , Corneal Diseases/drug therapy , Gram-Negative Bacteria/drug effects , Heterocyclic Compounds/pharmacology , Anti-Bacterial Agents/chemistry , Drug Resistance, Multiple, Bacterial/drug effects , Heterocyclic Compounds/chemistry , Humans , Microbial Sensitivity Tests
7.
ACS Infect Dis ; 6(1): 91-99, 2020 01 10.
Article in English | MEDLINE | ID: mdl-31646866

ABSTRACT

The priority pathogen list published by the World Health Organization (WHO) has categorized carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa as the top two critical pathogens, and hence, the development of novel antibacterial strategies to tackle such bacteria is highly necessary. Toward this aim, herein we report the efficacy of the combination of a lysine-based membrane-active small molecule, D-LANA-14 (d-lysine conjugated aliphatic norspermidine analogue bearing tetradecanoyl chain) and the obsolete/inactive antibiotics (such as tetracycline and rifampicin) to combat these superbugs. The combination of D-LANA-14 and the antibiotics tetracycline or rifampicin showed not only synergistic activity against growing planktonic cells of meropenem-resistant A. baumannii and P. aeruginosa clinical isolates but was also able to disrupt their established biofilms. More importantly, this synergistic effect was retained under the in vivo scenario, wherein the combination showed excellent efficacy in mice model of burn-wound infection with a drastic reduction of bacterial burden. A combined treatment of D-LANA-14 (40 mg/kg) and rifampicin (40 mg/kg) showed 4.9 log and 4.0 log reduction in A. baumannii and P. aeruginosa viability, respectively. On the contrary, individual treatment of D-LANA-14 decreased bacterial burden by 2.3 log (A. baumannii) and 1.3 log (P. aeruginosa) and rifampicin reduced about 3.0 log (A. baumannii) and 1.6 log (P. aeruginosa). Owing to the membrane-active nature imparted by D-LANA-14, bacteria could not develop resistance against the combined treatment, whereas a high-level of resistance development was observed against the last resort Gram-negative antibiotic, colistin. Taken together, the results therefore indicate a great potential of this novel combination to be developed as therapeutic regimen to combat infections caused by critical Gram-negative pathogens.


Subject(s)
Acinetobacter baumannii/drug effects , Drug Resistance, Multiple, Bacterial , Lysine/chemistry , Pseudomonas aeruginosa/drug effects , Rifampin/therapeutic use , Tetracycline/therapeutic use , Acinetobacter Infections/drug therapy , Animals , Anti-Bacterial Agents/therapeutic use , Bacterial Load , Bacterial Outer Membrane/drug effects , Biofilms/drug effects , Burns/drug therapy , Burns/microbiology , Drug Synergism , Drug Therapy, Combination , Female , Lysine/analogs & derivatives , Lysine/therapeutic use , Mice , Mice, Inbred BALB C , Microbial Sensitivity Tests , Pseudomonas Infections/drug therapy , Wound Infection/drug therapy , Wound Infection/microbiology
8.
ACS Appl Mater Interfaces ; 11(37): 33559-33572, 2019 Sep 18.
Article in English | MEDLINE | ID: mdl-31424189

ABSTRACT

An optimum hydrophilic/hydrophobic balance has been recognized as a crucial parameter in designing cationic polymers that mimic antimicrobial peptides (AMPs). To date, this balance was achieved either by hydrophilicity variation through altering the nature and the number of cationic charges or by hydrophobicity modulation through incorporation of alkyl groups of different chain lengths. However, how the hydrophobicity variation through AMPs' building blocks-amino acids-influences the antibacterial efficacy of AMP-mimicking cationic polymers has rarely been explored. Toward this goal, herein we report a class of amino acid conjugated polymers (ACPs) with tunable antibacterial activity through a simple post-polymer-functionalization strategy. Our polymeric design comprised a permanent cationic charge in every repeating unit, whereby the hydrophobicity was tuned through incorporation of different amino acids. Our results revealed that the amino acid alteration has a strong influence on antibacterial efficacy. Upon increasing the amino acid side-chain hydrophobicity, both the antibacterial activity (against broad spectrum of bacteria) and toxicity increased. However, the distinct feature of this class of polymers was their good activity against Acinetobacter baumannii-the top most critical pathogen according to WHO, which has created an alarming situation worldwide, causing the majority of infections in humans. A nontoxic (no hemolysis even at 1000 µg/mL) ACP including a glycine residue (ACP-1 (Gly)) showed very good activity (MIC = 8-16 µg/mL) against both drug-sensitive and drug-resistant strains of A. baumannii, including clinical isolates. This polymer not only was rapidly bactericidal against growing planktonic A. baumannii but also killed nondividing stationary-phase cells instantaneously (<2 min). Moreover, it eradicated the established biofilm formed by drug-resistant A. baumannii clinical isolates. No propensity for bacterial resistance development against this polymer was seen even after 14 continuous passages. Taken together, the results highlight that hydrophobicity modulation through incorporation of amino acids in cationic polymers will provide a significant opportunity in designing new ACPs with potent antibacterial activity and minimum toxicity toward mammalian cells. More importantly, the excellent anti-A. baumannii efficacy of the optimized lead polymer indicates its immense potential for being developed as therapeutic agent.


Subject(s)
Acinetobacter baumannii/physiology , Anti-Bacterial Agents , Biofilms/drug effects , Biomimetic Materials , Drug Resistance, Bacterial/drug effects , Polymers , Amino Acids/chemistry , Amino Acids/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Biofilms/growth & development , Biomimetic Materials/chemistry , Biomimetic Materials/pharmacology , HEK293 Cells , Humans , Polymers/chemistry , Polymers/pharmacology
9.
Biomacromolecules ; 19(6): 1888-1917, 2018 06 11.
Article in English | MEDLINE | ID: mdl-29718664

ABSTRACT

Global health is increasingly being threatened by the rapid emergence of drug-resistant microbes. The ability of these microbes to form biofilms has further exacerbated the scenario leading to notorious infections that are almost impossible to treat. For addressing this clinical threat, various antimicrobial polymers, polymer-based antimicrobial hydrogels and polymer-coated antimicrobial surfaces have been developed in the recent past. This review aims to discuss such polymer-based antimicrobial strategies with a focus on their current advancement in the field. Antimicrobial polymers, whose designs are inspired from antimicrobial peptides (AMPs), are described with an emphasis on structure-activity analysis. Additionally, antibiofilm activity and in vivo efficacy are delineated to elucidate the real potential of these antimicrobial polymers as possible therapeutics. Antimicrobial hydrogels, prepared from either inherently antimicrobial polymers or biocide-loaded into polymer-derived hydrogel matrix, are elaborated followed by various strategies to engineer polymer-coated antimicrobial surfaces. In the end, the current challenges are accentuated along with future directions for further expansion of the field toward tackling infections and antimicrobial resistance.


Subject(s)
Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Drug Resistance, Microbial/drug effects , Polymers/chemistry , Polymers/pharmacology , Antimicrobial Cationic Peptides/chemistry , Antimicrobial Cationic Peptides/pharmacology , Bacterial Adhesion/drug effects , Biofilms/drug effects , Disinfectants/pharmacokinetics , Drug Design , Humans , Hydrogels/chemistry , Hydrogels/pharmacology , Infections/drug therapy , Infections/microbiology , Structure-Activity Relationship
10.
Chem Commun (Camb) ; 54(39): 4943-4946, 2018 May 10.
Article in English | MEDLINE | ID: mdl-29700513

ABSTRACT

Here we report the design of membrane-active peptidomimetic molecules with a tunable arrangement of hydrophobic and polar groups. In spite of having the same chemical composition, the effective hydrophobicities of the compounds were different as a consequence of their chemical structure and conformational properties. The compound with lower effective hydrophobicity demonstrated antibacterial activity that was highly selective towards bacteria over mammalian cells. This study, highlighting the role in membrane selectivity of the specific arrangement of the different moieties in the molecular structure, provides useful indications for developing non-toxic antibacterial agents.


Subject(s)
Anti-Bacterial Agents/pharmacology , Peptidomimetics/pharmacology , Surface-Active Agents/pharmacology , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/toxicity , Cell Line, Transformed , Escherichia coli/drug effects , Humans , Hydrophobic and Hydrophilic Interactions , Liposomes/chemistry , Methicillin-Resistant Staphylococcus aureus/drug effects , Mice , Microbial Sensitivity Tests , Molecular Conformation , Molecular Dynamics Simulation , Molecular Structure , Peptidomimetics/chemistry , Peptidomimetics/toxicity , Pseudomonas aeruginosa/drug effects , Surface-Active Agents/chemistry , Surface-Active Agents/toxicity
11.
PLoS One ; 12(8): e0183263, 2017.
Article in English | MEDLINE | ID: mdl-28837596

ABSTRACT

Chronic bacterial biofilms place a massive burden on healthcare due to the presence of antibiotic-tolerant dormant bacteria. Some of the conventional antibiotics such as erythromycin, vancomycin, linezolid, rifampicin etc. are inherently ineffective against Gram-negative bacteria, particularly in their biofilms. Here, we report membrane-active macromolecules that kill slow dividing stationary-phase and antibiotic tolerant cells of Gram-negative bacteria. More importantly, these molecules potentiate antibiotics (erythromycin and rifampicin) to biofilms of Gram-negative bacteria. These molecules eliminate planktonic bacteria that are liberated after dispersion of biofilms (dispersed cells). The membrane-active mechanism of these molecules forms the key for potentiating the established antibiotics. Further, we demonstrate that the combination of macromolecules and antibiotics significantly reduces bacterial burden in mouse burn and surgical wound infection models caused by Acinetobacter baumannii and Carbapenemase producing Klebsiella pneumoniae (KPC) clinical isolate respectively. Colistin, a well-known antibiotic targeting the lipopolysaccharide (LPS) of Gram-negative bacteria fails to kill antibiotic tolerant cells and dispersed cells (from biofilms) and bacteria develop resistance to it. On the contrary, these macromolecules prevent or delay the development of bacterial resistance to known antibiotics. Our findings emphasize the potential of targeting the bacterial membrane in antibiotic potentiation for disruption of biofilms and suggest a promising strategy towards developing therapies for topical treatment of Gram-negative infections.


Subject(s)
Anti-Bacterial Agents/pharmacology , Gram-Negative Bacteria/drug effects , Animals , Biofilms , Colony Count, Microbial , Drug Synergism , Gram-Negative Bacteria/isolation & purification , Mice , Microbial Sensitivity Tests
12.
Chemistry ; 23(52): 12853-12860, 2017 Sep 18.
Article in English | MEDLINE | ID: mdl-28718982

ABSTRACT

Designing selective antibacterial molecules remains an unmet goal in the field of membrane-targeting agents. Herein, we report the rational design and synthesis of a new class of lipopeptides, which possess highly selective bacterial killing over mammalian cells. The selective interaction with bacterial over mammalian membranes was established through various spectroscopic, as well as microscopic experiments, including biophysical studies with the model membranes. A detailed antibacterial structure-activity relationship was delineated after preparing a series of molecules consisting of the peptide moieties with varied sequence of amino acids, such as d-phenylalanine, d-leucine, and d-lysine. Antibacterial activity was found to vary with the nature and positioning of hydrophobicity in the molecules, as well as number of positive charges. Optimized lipopeptide 9 did not show any hemolytic activity even at 1000 µg mL-1 and displayed >200-fold and >100-fold selectivity towards S. aureus and E. coli, respectively. More importantly, compound 9 was found to display good antibacterial activity (MIC 6.3-12.5 µg mL-1 ) against the five top most critical bacteria according to World Health Organization (WHO) priority pathogens list. Therefore, the results suggested that this new class of lipopeptides bear real promises for the development as future antibacterial agents.


Subject(s)
Anti-Bacterial Agents/chemical synthesis , Drug Design , Lipopeptides/chemistry , Amino Acids/chemistry , Amino Acids/metabolism , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Cell Wall/chemistry , Cell Wall/drug effects , Cell Wall/metabolism , Erythrocytes/cytology , Erythrocytes/drug effects , Erythrocytes/metabolism , Escherichia coli/drug effects , HEK293 Cells , Hemolysis/drug effects , Humans , Lipopeptides/chemical synthesis , Lipopeptides/pharmacology , Microbial Sensitivity Tests , Microscopy, Fluorescence , Permeability/drug effects , Staphylococcus aureus/drug effects , Structure-Activity Relationship
13.
Bioconjug Chem ; 28(4): 1194-1204, 2017 04 19.
Article in English | MEDLINE | ID: mdl-28225264

ABSTRACT

Methicillin-resistant Staphylococcus aureus (MRSA) has developed resistance to antibiotics of last resort such as vancomycin, linezolid, and daptomycin. Additionally, their biofilm forming capability has set an alarming situation in the treatment of bacterial infections. Herein we report the potency of fatty acid comprising lysine conjugates as novel anti-MRSA agents, which were not only capable of killing growing planktonic MRSA at low concentration (MIC = 3.1-6.3 µg/mL), but also displayed potent activity against nondividing stationary phase cells. Furthermore, the conjugates eradicated established biofilms of MRSA. The bactericidal activity of d-lysine conjugated tetradecanoyl analogue (D-LANA-14) is attributed to its membrane disruption against these metabolically distinct cells. In a mouse model of superficial skin infection, D-LANA-14 displayed potent in vivo anti-MRSA activity (2.7 and 3.9 Log reduction at 20 mg/kg and 40 mg/kg, respectively) without showing any skin toxicity even at 200 mg/kg of the compound exposure. Additionally, MRSA could not develop resistance against D-LANA-14 even after 18 subsequent passages, whereas the topical anti-MRSA antibiotic fusidic acid succumbed to rapid resistance development. Collectively, the results suggested that this new class of membrane targeting conjugates bear immense potential to treat MRSA infections over conventional antibiotic therapy.


Subject(s)
Anti-Bacterial Agents/chemical synthesis , Biofilms/drug effects , Lysine/chemistry , Methicillin-Resistant Staphylococcus aureus/drug effects , Animals , Fatty Acids/chemistry , Lysine/therapeutic use , Mice , Microbial Sensitivity Tests , Staphylococcal Skin Infections/drug therapy , Staphylococcal Skin Infections/microbiology
14.
ACS Omega ; 2(8): 5187-5195, 2017 Aug 31.
Article in English | MEDLINE | ID: mdl-30023741

ABSTRACT

Easily accessible 3,3'-diindolylmethanes (DIMs) were utilized to generate a focused library of indolo[2,3-b]quinolines (2), chromeno[2,3-b]indoles (3), and 3-alkenyl-oxindoles (4) under 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-mediated oxidative conditions. DIMs with ortho-NHTosyl (NHTs) phenyl group afforded indolo[2,3-b]quinolines (2), whereas DIMs with ortho-hydroxy phenyl groups yielded chromeno[2,3-b]indoles (3) and 3-alkenyl-oxindoles (4). The mild conditions and excellent yields of the products make this method a good choice to access a diverse library of bioactive molecules from a common starting material. Two optimized compounds 2a and 2n displayed excellent activity against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). Compound 2a showed the minimum inhibitory concentration values in the concentration between 1 and 4 µg/mL, whereas compound 2n revealed the values of 1-2 µg/mL. Furthermore, both the compounds were highly bactericidal and capable to kill the MRSA completely within 360 min. Collectively, the results suggested that both compounds 2a and 2n possess enormous potential to be developed as anti-MRSA agents.

15.
Viruses ; 8(11)2016 10 27.
Article in English | MEDLINE | ID: mdl-27801778

ABSTRACT

In light of the recent outbreak of Ebola virus (EBOV) disease in West Africa, there have been renewed efforts to search for effective antiviral countermeasures. A range of compounds currently available with broad antimicrobial activity have been tested for activity against EBOV. Using live EBOV, eighteen candidate compounds were screened for antiviral activity in vitro. The compounds were selected on a rational basis because their mechanisms of action suggested that they had the potential to disrupt EBOV entry, replication or exit from cells or because they had displayed some antiviral activity against EBOV in previous tests. Nine compounds caused no reduction in viral replication despite cells remaining healthy, so they were excluded from further analysis (zidovudine; didanosine; stavudine; abacavir sulphate; entecavir; JB1a; Aimspro; celgosivir; and castanospermine). A second screen of the remaining compounds and the feasibility of appropriateness for in vivo testing removed six further compounds (ouabain; omeprazole; esomeprazole; Gleevec; D-LANA-14; and Tasigna). The three most promising compounds (17-DMAG; BGB324; and NCK-8) were further screened for in vivo activity in the guinea pig model of EBOV disease. Two of the compounds, BGB324 and NCK-8, showed some effect against lethal infection in vivo at the concentrations tested, which warrants further investigation. Further, these data add to the body of knowledge on the antiviral activities of multiple compounds against EBOV and indicate that the scientific community should invest more effort into the development of novel and specific antiviral compounds to treat Ebola virus disease.


Subject(s)
Antiviral Agents/pharmacology , Drug Evaluation, Preclinical/methods , Ebolavirus/drug effects , Animals , Antiviral Agents/administration & dosage , Cell Line , Disease Models, Animal , Guinea Pigs , Hemorrhagic Fever, Ebola/drug therapy , Humans , Treatment Outcome
16.
J Med Chem ; 59(23): 10750-10762, 2016 12 08.
Article in English | MEDLINE | ID: mdl-27809517

ABSTRACT

More than 80% of the bacterial infections are associated with biofilm formation. To combat infections, amphiphilic small molecules have been developed as promising antibiofilm agents. However, cytotoxicity of such molecules still remains a major problem. Herein we demonstrate a concept in which antibacterial versus cytotoxic activities of cationic small molecules are tuned by spatial positioning of hydrophobic moieties while keeping positive charges constant. Compared to the molecules with more pendent hydrophobicity from positive centers (MIC = 1-4 µg/mL and HC50 = 60-65 µg/mL), molecules with more confined hydrophobicity between two centers show similar antibacterial activity but significantly less toxicity toward human erythrocytes (MIC = 1-4 µg/mL and HC50 = 805-1242 µg/mL). Notably, the optimized molecule is shown to be nontoxic toward human cells (HEK 293) at a concentration at which it eradicates established bacterial biofilms. The molecule is also shown to eradicate preformed bacterial biofilm in vivo in a murine model of superficial skin infection.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Biofilms/drug effects , Skin Diseases, Bacterial/drug therapy , Small Molecule Libraries/pharmacology , Animals , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Cations/chemical synthesis , Cations/chemistry , Cations/pharmacology , Cell Survival/drug effects , Disease Models, Animal , Dose-Response Relationship, Drug , Female , HEK293 Cells , Humans , Mice , Mice, Inbred BALB C , Microbial Sensitivity Tests , Molecular Structure , Skin Diseases, Bacterial/microbiology , Small Molecule Libraries/chemical synthesis , Small Molecule Libraries/chemistry , Structure-Activity Relationship
17.
ChemMedChem ; 11(21): 2367-2371, 2016 Nov 07.
Article in English | MEDLINE | ID: mdl-27731959

ABSTRACT

In the global effort to thwart antimicrobial resistance, lipopeptides are an important class of antimicrobial agents, especially against Gram-negative infections. In an attempt to circumvent their synthetic complexities, we designed simple membrane-active agents involving only one amino acid and two lipid tails. Herein we show that the use of two short lipid tails instead of a single long one significantly increases selective antibacterial activity. This study yielded several selective antibacterial compounds, and investigations into the properties of this compound class were conducted with the most active compound. Fluorescence spectroscopic studies revealed the capacity of the representative compound to cause depolarization and permeabilization of bacterial cell membranes. This membrane-active nature of the compound imparts superior activity against persister cells, biofilms, and planktonic cells. Topical application of the compound decreased bacterial burden in mice inflicted with burn-infections caused by Acinetobacter baumannii. We anticipate that the design principles described herein will direct the development of several antimicrobial agents of clinical importance.

18.
ACS Infect Dis ; 2(2): 111-22, 2016 02 12.
Article in English | MEDLINE | ID: mdl-27624962

ABSTRACT

Infections caused by drug-resistant Gram-negative pathogens continue to be significant contributors to human morbidity. The recent advent of New Delhi metallo-ß-lactamase-1 (blaNDM-1) producing pathogens, against which few drugs remain active, has aggravated the problem even further. This paper shows that aryl-alkyl-lysines, membrane-active small molecules, are effective in treating infections caused by Gram-negative pathogens. One of the compounds of the study was effective in killing planktonic cells as well as dispersing biofilms of Gram-negative pathogens. The compound was extremely effective in disrupting preformed biofilms and did not select resistant bacteria in multiple passages. The compound retained activity in different physiological conditions and did not induce any toxic effect in female Balb/c mice until concentrations of 17.5 mg/kg. In a murine model of Acinetobacter baumannii burn infection, the compound was able to bring the bacterial burden down significantly upon topical application for 7 days.


Subject(s)
Acinetobacter baumannii/drug effects , Anti-Bacterial Agents/pharmacology , Burns/microbiology , Lysine/analogs & derivatives , Lysine/pharmacology , Wound Infection/microbiology , Animals , Biofilms/drug effects , Disease Models, Animal , Drug Resistance, Bacterial , Female , Mice , Mice, Inbred BALB C , Microbial Sensitivity Tests , beta-Lactamases/metabolism
19.
Mol Pharm ; 13(10): 3578-3589, 2016 10 03.
Article in English | MEDLINE | ID: mdl-27589087

ABSTRACT

The continuous rise of antimicrobial resistance and the dearth of new antibiotics in the clinical pipeline raise an urgent call for the development of potent antimicrobial agents. Cationic chitosan derivatives, N-(2-hydroxypropyl)-3-trimethylammonium chitosan chlorides (HTCC), have been widely studied as potent antibacterial agents. However, their systemic structure-activity relationship, activity toward drug-resistant bacteria and fungi, and mode of action are very rare. Moreover, toxicity and efficacy of these polymers under in vivo conditions are yet to be established. Herein, we investigated antibacterial and antifungal efficacies of the HTCC polymers against multidrug resistant bacteria including clinical isolates and pathogenic fungi, studied their mechanism of action, and evaluated cytotoxic and antimicrobial activities in vitro and in vivo. The polymers were found to be active against both bacteria and fungi (MIC = 125-250 µg/mL) and displayed rapid microbicidal kinetics, killing pathogens within 60-120 min. Moreover, the polymers were shown to target both bacterial and fungal cell membrane leading to membrane disruption and found to be effective in hindering bacterial resistance development. Importantly, very low toxicity toward human erythrocytes (HC50 = >10000 µg/mL) and embryo kidney cells were observed for the cationic polymers in vitro. Further, no inflammation toward skin tissue was observed in vivo for the most active polymer even at 200 mg/kg when applied on the mice skin. In a murine model of superficial skin infection, the polymer showed significant reduction of methicillin-resistant Staphylococcus aureus (MRSA) burden (3.2 log MRSA reduction at 100 mg/kg) with no to minimal inflammation. Taken together, these selectively active polymers show promise to be used as potent antimicrobial agents in topical and other infections.


Subject(s)
Anti-Infective Agents/therapeutic use , Chitosan/analogs & derivatives , Quaternary Ammonium Compounds/chemistry , Quaternary Ammonium Compounds/therapeutic use , Animals , Anti-Infective Agents/administration & dosage , Anti-Infective Agents/adverse effects , Cell Survival/drug effects , Chitosan/adverse effects , Chitosan/chemistry , Chitosan/therapeutic use , Drug Resistance, Fungal , Drug Resistance, Multiple, Bacterial , Female , Humans , Methicillin-Resistant Staphylococcus aureus/drug effects , Methicillin-Resistant Staphylococcus aureus/pathogenicity , Mice , Mice, Inbred BALB C , Microbial Sensitivity Tests , Quaternary Ammonium Compounds/adverse effects , Staphylococcal Skin Infections/drug therapy , Structure-Activity Relationship
20.
Chem Commun (Camb) ; 52(69): 10582, 2016 Sep 07.
Article in English | MEDLINE | ID: mdl-27502077

ABSTRACT

Correction for 'Selective and broad spectrum amphiphilic small molecules to combat bacterial resistance and eradicate biofilms' by Jiaul Hoque et al., Chem. Commun., 2015, 51, 13670-13673.

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