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UID:13@deq.fe.up.pt
DTSTART:20191205T163000Z
DTEND:20191205T163000Z
DTSTAMP:20210407T163426Z
URL:https://deq.fe.up.pt/events/delivery-of-nucleid-acid-mimics-nams-into-
 bacteria/
SUMMARY:Delivery of nucleid acid mimics (NAMs) into bacteria
DESCRIPTION:Sara S Pereira\, LEPABE | December 5\, 2019 – 16h30 | FEUP Sa
 la B020\n\nStudent Seminar in Chemical Engineering (DEQ-FEUP)\n\nTreatment
  of septicaemia is threatened by the bacterial resistance to antibiotics. 
 Nucleic acid mimics (NAMs) able to inhibit bacterial genes are emerging as
  an alternative to traditional antibiotics. However\, NAMs cannot passivel
 y permeate the multi-layered bacterial envelope. Therefore\, liposomes wer
 e considered as possible carriers to facilitate the internalization of NAM
 s in bacteria. Locked nucleic acids (LNA) and 2´-OMethylRNA (2´OMe) were
  evaluated as model NAMs and formulated into DOTAP-DOPE liposomes\, formin
 g lipoplexes. To improve the colloidal stability of the lipoplexes\,  EGy
 lated lipids (DSPE-PEG) were added to the formulation. We investigated the
  complexation and colloidal stability of these lipoplexes in human serum\,
  which is of relevance in the context of intravenous administration. The p
 otential of these lipoplexes to fuse with the envelope of Gram-negative an
 d Grampositive bacteria and deliver the NAMs into the bacterial cytosol wa
 s then assessed. Fluorescence correlation spectroscopy (FCS) and nanoparti
 cle tracking analysis were used to respectively study the complexation and
  colloidal stability of lipoplexes\, with and without DSPE-PEG post-PEGyla
 tion\, directly in human serum\, over time. Thereafter\, the interaction o
 f liposomes with the cell envelope of Escherichia coli and Staphylococcus 
 aureus was studied via a lipid mixing assay. Fluorescence in situ hybridiz
 ation (FISH) and confocal laser scanning microscopy (CLSM) analysis then e
 nabled the evaluation of the extent of NAMs internalization into the refer
 red bacteria. Our data showed good complexation stability of the NAMs in t
 he human serum for the PEGylated liposomes. Liposomes were able to fuse wi
 th both the Gram-negative and Gram-positive bacteria tested. Accordingly\,
  the confocal images taken after the FISH assay demonstrated a successful 
 internalization of the NAMs in both bacteria. We demonstrated that DOTAP-D
 OPE liposomes may fuse with both Gram-negative and Gram-positive bacteria 
 and successfully deliver NAMs in both bacterial types. In addition\, NAMs 
 remain stably complexed within the lipoplexes even when incubated.\n\n\n\n
 Sara S Pereira graduated in Biology at the University of Aveiro and holds 
 a MSc in Microbiology from the same University. In 2017\, she started her 
 PhD fellowship on the “Targeted delivery of nucleic acid mimics into Esc
 herichia coli and Staphylococcus aureus as a novel method for treatment of
  the infection” at the Associated Laboratory LEPABE in FEUP. Currently\,
  she is enrolled on the 3rd year of the PDEQB doctoral program\, under the
  supervision of Professor Nuno Azevedo from FEUP and Professor Stefaan De 
 Smedt from Ghent University.\n\n\n\n&nbsp\;\n\n[Host: Joaquim L Faria\, As
 sociate Laboratory\, LSRE-LCM]\nImage credits: Sara S Pereira
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 1205_1630_SPereira_1920_1S-SEMI-e1576264778800.jpg
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