02832nas a2200217   4500008004100000022001400041245012000055210006900175260000800244300001200252490000600264520205600270100002002326700002102346700002702367700001602394700003002410700002202440700002302462856012902485       2016                        eng d  a2470-134300aGlycopolypeptide-grafted bioactive polyionic complex vesicles (PICsomes) and their specific polyvalent interactions0 aGlycopolypeptidegrafted bioactive polyionic complex vesicles PIC  cOCT  a600-6120 v13 a<p>Glycopolypeptide-based self-assembled nano-/microstructures with surface-tethered carbohydrates are excellent mimics of glycoproteins on the cell surface. To expand the broad repertoire of glycopolypeptide-based supramolecular soft structures such as polymersomes formed via self-assembly of amphiphilic polymers, we have developed a new class of polyionic complex vesicles (PICsomes) with glycopolypeptides grafted on the external surface. Oppositely charged hydrophilic block copolymers of glycopolypeptide(20)-b-poly-L-lysine(100) and PEG(2k)-b-poly-L-glutamate(100) [PEG = poly(ethylene glycol)] were synthesized using a combination of ring-opening polymerization of N-carboxyanhydrides and ``click'' chemistry. Under physiological conditions, the catiomer and aniomer self-assemble to form glycopolypeptide-conjugated PICsomes (GP-PICsomes) of micrometer dimensions. Electron and atomic force microscopy suggests a hollow morphology of the PICsomes, with inner aqueous pool (core) and peripheral PIC (shell) regions. Owing to their relatively large (similar to micrometers) size, the hollowness of the supramolecular structure could be established via fluorescence microscopy of single GP-PICsomes, both in solution and under dry conditions, using spatially distributed fluorescent probes. Furthermore, the dynamics of single PICsomes in solution could be imaged in real time, which also allowed us to test for multivalent interactions between PICsomes mediated by a carbohydrate (mannose)-binding protein (lectin, Con-A). The immediate association of several GP-PICsomes in the presence of Con-A and their eventual aggregation to form large insoluble aggregate clusters reveal that upon self-assembly carbohydrate moieties protrude on the outer surface which retains their biochemical activity. Challenge experiments with excess mannose reveal fast deaggregation of GP-PICsomes as opposed to that in the presence of excess galactose, which further establishes the specificity of lectin-mediated polyvalent interactions of the GP-PICsomes.</p>1 aPandey, Bhawana1 aMahato, Jaladhar1 aCotta, Karishma, Berta1 aDas, Soumen1 aSharma, Dharmendar, Kumar1 aGupta, Sayam, Sen1 aChowdhury, Arindam  uhttps://library.ncl.res.in/content/glycopolypeptide-grafted-bioactive-polyionic-complex-vesicles-picsomes-and-their-specific02545nas a2200277   4500008004100000022001400041245012300055210006900178260000800247300001100255490000800266520161900274653001301893653002601906653001401932653001601946653001901962653001701981653003101998100002102029700002702050700002202077700002402099700001802123856012602141       2021                        eng d  a0882-401000aPNA-mediated efflux inhibition as a therapeutic strategy towards overcoming drug resistance in Mycobacterium smegmatis0 aPNAmediated efflux inhibition as a therapeutic strategy towards   cFEB  a1047370 v1513 a<p>The emergence of antibiotic-resistant strains of Mycobacterium tuberculosis and the decelerating development of new and effective antibiotics has impaired the treatment of tuberculosis (TB). Efflux pump inhibitors (EPIs) have the potential to improve the efficacy of existing anti-TB drugs although with toxicity limitations. Peptide nucleic acids (PNAs), oligonucleotide mimics, by virtue of their high nucleic acid binding specificity have the capability to overcome this drawback. We, therefore, investigated the efflux pump inhibitory properties of a PNA designed against an efflux pump of Mycobacterium smegmatis. LfrA, an efflux pump found in M. smegmatis, is majorly involved in conferring innate drug resistance to this strain and, therefore, was selected as a target for gene silencing via PNA. qRT-PCR and EtBr assays confirmed the EPI activity of the anti-lfrA PNA. On testing the effect of the anti-lfrA PNA on the bactericidal activity of a fluoroquinolone, norfloxacin, we observed that 5 mu M of anti-lfrA PNA in combination with norfloxacin led to an enhanced killing of up to 2.5 log-fold against wild-type and a lab-generated multidrug resistant strain, exemplifying its potential in countering resistance. Improved efficacy was also observed against intra-macrophage mycobacteria, where the drug-PNA combination enhanced bacterial clearance by 1.3 log-fold. Further, no toxicity was observed with PNA concentrations up to 4 times higher than the efficacious anti-lfrA PNA concentration. Thus, PNA, as an adjuvant, presents a novel and viable approach to rejuvenate anti-TB therapeutics.</p>
10aAdjuvant10aAntibiotic resistance10aAntisense10aEfflux pump10aGene silencing10aMycobacteria10aPeptide nucleic acid (PNA)1 aGhosh, Saptarshi1 aCotta, Karishma, Berta1 aHande, Aniket, A.1 aFernandes, Moneesha1 aMehra, Sarika  uhttps://library.ncl.res.in/content/pna-mediated-efflux-inhibition-therapeutic-strategy-towards-overcoming-drug-resistance