Unraveling the potential of M13 phages in biomedicine: Advancing drug nanodelivery and gene therapy

Development and application of an interbacterial DNA delivery system based on M13 bacteriophage

With the rapid development in synthetic biology, bacterial therapy has been widely applied in disease diagnosis and treatment. A key step in regulating the execution of specific instructions by engineered bacteria in vivo involves the transfer of information between bacteria. Currently, small molecule compounds and proteins are commonly used as carriers for inter-bacterial information transfer. However, DNA, as an information carrier, boasts higher information capacity and ease of editing. Based on this, we have developed an engineered bacterial DNA delivery system using M13 bacteriophage to study the cooperative response mechanisms between bacteria. Firstly, we leveraged the ability of engineered bacteria to secrete phagemid DNA into the extracellular environment via bacteriophages and to acquire phagemid DNA through infection by extracellular phagemids, thereby developing a dynamic phagemid replenishment system. This system can maintain the stability of phagemid DNA in environments lacking antibiotic selection pressure, constructing a stable DNA delivery platform for phagemid output. Subsequently, using this engineered bacterial DNA delivery system, we modularized gene circuits and placed them in two different engineered bacteria. Through DNA transfer, we achieved a cooperative response to signals between the two bacteria, laying the groundwork for multi-bacterial joint regulation. Our research not only provides an effective tool for information transfer in engineered bacteria but also offers a novel approach for multi-bacterial therapy.

Male-specific bacteriophages and their potential on combating the spreading of T4SS-bearing antimicrobial resistance plasmids

Antimicrobial resistance (AMR) has been recognized as an important health crisis in the twenty first century. Type IV secretion systems (T4SSs) play key roles in the dissemination of AMR plasmids. Novel strategies that combat AMR problem by targeting T4SS sprung up in recent years. Here, we focus on the strategy of male-specific phages that could target and kill bacteria carrying conjugative AMR plasmids encoding T4SSs. We reviewed the recent advances in male-specific phages, including anti-conjugation mechanisms, clinical isolation and identification methods, classification and characteristics, in vitro and in vivo anti-conjugation efficacy and improving strategies. Male-specific phages constitute exciting candidates for developing sustainable anti-resistance biocontrol applications.

The enhancement of M13 phage titration by optimizing the origin of replication

Background and purpose

M13KO7, a modified M13 phage variant, carries the p15A replication origin and Tn903 kanamycin resistance gene. This study aimed to optimize M13KO7's replication by substituting the p15A origin with the higher-copy pMB1 origin (500-700 copy numbers).

Experimental approach

A 6431-nucleotide fragment from the M13KO7 plasmid lacking the p15A replication origin and kanamycin resistance gene was amplified using a long polymerase chain reaction (PCR). The modified M13AMB1 plasmid was created by adding adenine to the 3' ends of this fragment and ligating it to the pMB1-containing fragment using T/A cloning. Afterward, to prepare the phage, pM13AMB1 was transformed into E. coli TG1 bacteria, and then, using the PEG-NaCl precipitation, the modified phage was propagated. The modified phage titer was determined utilizing the serial dilution and the qPCR methods, compared with the M13KO7 phage.

Findings/Results

The results showed that in the serial dilution method, the titers of modified phage and M13KO7 phage were 4.8 × 1014 and 7 × 1012 pfu/mL, respectively. Besides, the phage titer calculated by the qPCR method for the modified phage was equal to 1.3 × 109 pfu/mL, whereas it was 4.08 × 108 pfu/mL for the M13KO7 phage.

Conclusion and implications

This study provides evidence that replication origin replacement led to a significant increase in phage titers. It highlights the importance of replication optimization for molecular biology applications.

Circular Single-Stranded DNA: Discovery, Biological Effects, and Applications

The field of nucleic acid therapeutics has witnessed a significant surge in recent times, as evidenced by the increasing number of approved genetic drugs. However, current platform technologies containing plasmids, lipid nanoparticle-mRNAs, and adeno-associated virus vectors encounter various limitations and challenges. Thus, we are devoted to finding a novel nucleic acid vector and have directed our efforts toward investigating circular single-stranded DNA (CssDNA), an ancient form of nucleic acid. CssDNAs are ubiquitous, but generally ignored. Accumulating evidence suggests that CssDNAs possess exceptional properties as nucleic acid vectors, exhibiting great potential for clinical applications in genetic disorders, gene editing, and immune cell therapy. Here, we comprehensively review the discovery and biological effects of CssDNAs as well as their applications in the field of biomedical research for the first time. Undoubtedly, as an ancient form of DNA, CssDNA holds immense potential and promises novel insights for biomedical research.

Developing recombinant antibodies by phage display technology to neutralize viral infectious diseases

The use of recombinant antibodies developed through phage display technology offers a promising approach for combating viral infectious diseases. By specifically targeting antigens on viral surfaces, these antibodies have the potential to reduce the severity of infections or even prevent them altogether. With the emergence of new and more virulent strains of viruses, it is crucial to develop innovative methods to counteract them. Phage display technology has proven successful in generating recombinant antibodies capable of targeting specific viral antigens, thereby providing a powerful tool to fight viral infections. In this mini-review article, we examine the development of these antibodies using phage display technology, and discuss the associated challenges and opportunities in developing novel treatments for viral infectious diseases. Furthermore, we provide an overview of phage display technology. As these methods continue to evolve and improve, novel and sophisticated tools based on phage display and peptide display systems are constantly emerging, offering exciting prospects for solving scientific, medical, and technological problems related to viral infectious diseases in the near future.

Harnessing filamentous phages for enhanced stroke recovery

Stroke poses a critical global health challenge, leading to substantial morbidity and mortality. Existing treatments often miss vital timeframes and encounter limitations due to adverse effects, prompting the pursuit of innovative approaches to restore compromised brain function. This review explores the potential of filamentous phages in enhancing stroke recovery. Initially antimicrobial-centric, bacteriophage therapy has evolved into a regenerative solution. We explore the diverse role of filamentous phages in post-stroke neurological restoration, emphasizing their ability to integrate peptides into phage coat proteins, thereby facilitating recovery. Experimental evidence supports their efficacy in alleviating post-stroke complications, immune modulation, and tissue regeneration. However, rigorous clinical validation is essential to address challenges like dosing and administration routes. Additionally, genetic modification enhances their potential as injectable biomaterials for complex brain tissue issues. This review emphasizes innovative strategies and the capacity of filamentous phages to contribute to enhanced stroke recovery, as opposed to serving as standalone treatment, particularly in addressing stroke-induced brain tissue damage.