Curated Optogenetic Publication Database

Abstract: Engineered bacteria-based cancer therapy has increasingly been considered to be a promising therapeutic strategy due to the development of synthetic biology. Wherein, engineering bacteria-mediated photodynamic therapy (PDT)-immunotherapy shows greater advantages and potential in treatment efficiency than monotherapy. However, the unsustainable regeneration of photosensitizers (PSs) and weak immune responses limit the therapeutic efficiency. Herein, we developed an engineered bacteria-based delivery system for sequential delivery of PSs and checkpoint inhibitors in cancer PDT-immunotherapy. The biosynthetic pathway of 5-aminolevulinic acid (5-ALA) was introduced into Escherichia coli, yielding a supernatant concentration of 172.19 mg/L after 10 h of growth. And another strain was endowed with the light-controllable releasement of anti-programmed cell death-ligand 1 nanobodies (anti-PD-L1). This system exhibited a collaborative effect, where PDT initiated tumor cell death and the released tumor cell fragments stimulated immunity, followed by the elimination of residual tumor cells. The tumor inhibition rate reached 74.97%, and the portion of activated T cells and inflammatory cytokines were reinforced. The results demonstrated that the engineered bacteria-based collaborative system could sequentially deliver therapeutic substance and checkpoint inhibitors, and achieve good therapeutic therapy. This paper will provide a new perspective for the cancer PDT-immunotherapy.

Abstract: The ideal engineered microbial smart-drug should be capable of functioning on demand at specific sites in vivo. However, precise regulation of engineered microorganisms poses challenges in the convoluted and elongated intestines. Despite the promising application potential of optogenetic regulation strategies based on light signals, the poor tissue penetration of light signals limits their application in large experimental animals. Given the rapid development of ingestible electronic capsules in recent years, taking advantage of them as regulatory devices to deliver light signals in situ to engineered bacteria within the intestines has become feasible. In this study, we established an electronic-microorganism signaling system, realized by two Bluetooth-controlled luminescent electronic capsules were designed. The “Manager” capsule is equipped with a photosensor to monitor the distribution of engineered bacteria and to activate the optogenetic function of the bacteria by emitting green light. The other capsule, “Locator”, can control the in situ photopolymerization of hydrogels in the intestines via ultraviolet light, aiding in the retention of engineered bacteria at specific sites. These two electronic capsules are expected to work synergistically to regulate the distribution and function of engineered bacteria in vivo, and their application in the treatment of colitis in pigs is currently being investigated, with relevant results to be updated subsequently.

Abstract: Engineering bacteria can achieve targeted and controllable cancer therapy using synthetic biology technology and the characteristics of tumor microenvironment. Besides, the accurate tumor diagnosis and visualization of the treatment process are also vital for bacterial therapy. In this paper, a light control engineered bacteria system based on upconversion nanoparticles (UCNP)-mediated time-resolved imaging (TRI) was constructed for colorectal cancer theranostic and therapy. UCNP with different luminous lifetimes were separately modified with the tumor targeting molecule (folic acid) or anaerobic bacteria (Nissle 1917, EcN) to realize the co-localization of tumor tissues, thus improving the diagnostic accuracy based on TRI. In addition, blue light was used to induce engineered bacteria (EcN-pDawn-φx174E/TRAIL) lysis and the release of tumor apoptosis-related inducing ligand (TRAIL), thus triggering tumor cell death. In vitro and in vivo results indicated that this system could achieve accurate tumor diagnosis and light-controlled cancer therapy. EcN-pDawn-φx174E/TRAIL with blue light irradiation could inhibit 53% of tumor growth in comparison to that without blue light irradiation (11.8%). We expect that this engineered bacteria system provides a new technology for intelligent bacterial therapy and the construction of cancer theranostics.

Abstract: Subcutaneous administration of sustained-release formulations is a common strategy for protein drugs, which avoids first pass effect and has high bioavailability. However, conventional sustained-release strategies can only load a limited amount of drug, leading to insufficient durability. Herein, we developed microcapsules based on engineered bacteria for sustained release of protein drugs. Engineered bacteria were carried in microcapsules for subcutaneous administration, with a production-lysis circuit for sustained protein production and release. Administrated in diabetic rats, engineered bacteria microcapsules was observed to smoothly release Exendin-4 for 2 weeks and reduce blood glucose. In another example, by releasing subunit vaccines with bacterial microcomponents as vehicles, engineered bacterial microcapsules activated specific immunity in mice and achieved tumor prevention. The engineered bacteria microcapsules have potential to durably release protein drugs and show versatility on the size of drugs. It might be a promising design strategy for long-acting in situ drug factory.

Abstract: The discovery of the gut-brain axis has proven that brain functions can be affected by the gut microbiota's metabolites, so there are significant opportunities to explore new tools to regulate gut microbiota and thus work on the brain functions. Meanwhile, engineered bacteria as oral live biotherapeutic agents to regulate the host's healthy homeostasis have attracted much attention in microbial therapy. However, whether this strategy is able to remotely regulate the host's brain function in vivo has not been investigated. Here, we engineered three blue-light-responsive probiotics as oral live biotherapeutic agents. They are spatiotemporally delivered and controlled by the upconversion optogenetic micro-nano system. This micro-nano system promotes the small intestine targeting and production of the exogenous L. lactis in the intestines, which realizes precise manipulation of brain functions including anxiety behavior, Parkinson's disease, and vagal afferent. The noninvasive and real-time probiotic intervention strategy makes the communiation from the gut to the host more controllable, which will enable the potential for engineered microbes accurately and effectively regulating a host's health.

Abstract: Recombinant bacterial colonization plays an indispensable role in disease prevention, alleviation, and treatment. Successful application mainly depends on whether bacteria can efficiently spatiotemporally colonize the host gut. However, a primary limitation of existing methods is the lack of precise spatiotemporal regulation, resulting in uncontrolled methods that are less effective. Herein, we design upconversion microgels (UCMs) to convert near-infrared light (NIR) into blue light to activate recombinant light-responsive bacteria (Lresb) in vivo, where autocrine "functional cellular glues" made of adhesive proteins assist Lresb inefficiently colonizing the gut. The programmable engineering platform is further developed for the controlled and effective colonization of Escherichia coli Nissle 1917 (EcN) in the gut. The colonizing bacteria effectively alleviate DSS-induced colitis in mice. We anticipate that this approach could facilitate the clinical application of engineered microbial therapeutics to accurately and effectively regulate host health.

Abstract: Engineered anaerobic bacteria known as live biotherapeutic products (LBPs) have shown great advances in cancer therapy. One advantage of anaerobic bacteria as drug carrier is that it spontaneously target to tumor and persistently release anti-tumor factors. To realize effective anti-cancer therapeutics, one essential premise is to improve the controllability of treatment. Here, we designed near-infrared (NIR)-light responsive bacteria as anti-tumor agent, which is based on a blue-light responsive module and upconversion nanoparticles. The upconversion nanoparticles converted external NIR light to local blue light to noninvasively activate blue-light responsive module (EL222) in engineered LBPs. The activated LBPs then produce tumor necrosis factor α (TNFα) for precise tumor ablation. In vitro and in vivo results have proven that this engineered NIR-light-responsive bacteria could efficiently inhibit tumor growth. We anticipate that this controllable and safe bacteria-based therapy can facilitate the application of LBPs to accurately and effectively regulate diseases.