Therapeutic applications of nucleic acid aptamers in microbial infections

Abstract

Today, the treatment of bacterial infections is a major challenge, due to growing rate of multidrug-resistant bacteria, complication of treatment and increased healthcare costs. Moreover, new treatments for bacterial infections are limited. Oligonucleotide aptamers are single stranded DNAs or RNAs with target-selective high-affinity feature, which considered as nucleic acid-based affinity ligands, replacing monoclonal antibodies. The aptamer-based systems have been found to be talented tools in the treatment of microbial infections, regarding their promising anti-biofilm and antimicrobial activities; they can reduce or inhibit the effects of bacterial toxins, and inhibit pathogen invasion to immune cell, as well as they can be used in drug delivery systems. The focus of this review is on the therapeutic applications of aptamers in infections. In this regard, an introduction of infections and related challenges were presented, first. Then, aptamer definition and selection, with a brief history of aptamers development against various pathogens and toxins were reviewed. Diverse strategies of aptamer application in drug delivery, as well as, the effect of aptamers on the immune system, as the main natural agents of human defense against pathogens, were also discussed. Finally, the future trends in clinical applications of this technology were discussed.

Fluorescent aptamers for detection and treatment of pathogenic bacteria and cancer

“…Having shown their promise as diagnostic agents, aptamers are now the burgeoning as therapeutics against microbes and cancer cells. The drive to find alternatives to antibiotics is stronger than ever because of increasing resistance to these agents amongst microbes (Afrasiabi et al, 2020). Staphylococcus aureus and Pseudomonas aeruginosa are some of the prime examples of pathogenic bacteria that have developed antibiotic-resistant strains responsible for nosocomial infections (MacDougall et al, 2005).…”

Nucleic Acid Hybrids as Advanced Antibacterial Nanocarriers

“…In addition to achieving enhanced cellular uptake of antimicrobial agents, specific binding of DNA nanostructured hybrid systems with high affinity and selectivity to other bacteria targets, proteins or small molecules can be considered to improve clinical efficacy/outcome [33]. Within this context, aptamers which are small single-stranded DNA sequences have been evaluated with success as treatment modalities against bacteria biofilms and toxins [33].…”

“…In addition to achieving enhanced cellular uptake of antimicrobial agents, specific binding of DNA nanostructured hybrid systems with high affinity and selectivity to other bacteria targets, proteins or small molecules can be considered to improve clinical efficacy/outcome [33]. Within this context, aptamers which are small single-stranded DNA sequences have been evaluated with success as treatment modalities against bacteria biofilms and toxins [33]. For instance, considering the impact of motility on the initial attachment of bacteria to form biofilms, pretreatment of Salmonella Choleraesuis aptamers initiated specific binding to the flagella to prevent the formation of mature biofilms [140].…”

“…These nanocarriers possess excellent biocompatibility, biodegradability and targeting properties [18]. For instance, aptamer-based systems have been shown to be efficient as promising tools against bacterial biofilms, possess excellent antimicrobial activities, inhibit immune cell invasion and reduce the effect of bacterial toxins [33].…”

Virus-associated ribozymes and nano carriers against COVID-19

“…Inhibitors are commonly used in anti-viral treatments. However, repeated virus mutations and viruses escaping immune system cells may be ineffective in binding viral inhibitors to their targets and cause toxicity and serious side effects due to non-specific binding [19][20][21][22][23]. At the same time, the interaction of inhibitors with other molecules can lead to low efficacy [24].…”