An Antibody-directed and Immune Response Modifier-augmented Photothermal Therapy Strategy Relieves Aging via Rapid Immune Clearance of Senescent Cells.

Cellular senescence is an irreversible and multifaceted process inducing tissue dysfunction and organismal aging, and thus the clearance of senescent cells can prevent or delay the onset of aging-related pathologies. Herein, we developed an augmented photothermal therapy strategy integrated with an antibody against ß2-microglobulin (aB2MG) and an immune adjuvant imiquimod (R837) to effectively accelerate senescent cell apoptosis and clearance under a near-infrared light. With this strategy, the designed CroR@aB2MG enables the targeting of senescent cells and the application of photothermal therapy concomitantly, the initiation of immune clearance subsequently, and finally the realization of protective effects against senescence. Our results showed that the photo-induced heating effect caused senescent cells to quickly undergo apoptosis and the synchronous immune response accelerated the clearance of senescent cells in vitro and in vivo. Therefore, this photoactivated speedy clearing strategy may provide an efficient way for the treatment of senescence-related diseases by eliminating senescent cells with biomaterials.

An Antibody-directed and Immune Response Modifier-augmented Photothermal Therapy Strategy Relieves Aging via Rapid Immune Clearance of Senescent Cells.

Cellular senescence is an irreversible and multifaceted process inducing tissue dysfunction and organismal aging, and thus the clearance of senescent cells can prevent or delay the onset of aging-related pathologies. Herein, we developed an augmented photothermal therapy strategy integrated with an antibody against ß2-microglobulin (aB2MG) and an immune adjuvant imiquimod (R837) to effectively accelerate senescent cell apoptosis and clearance under a near-infrared light. With this strategy, the designed CroR@aB2MG enables the targeting of senescent cells and the application of photothermal therapy concomitantly, the initiation of immune clearance subsequently, and finally the realization of protective effects against senescence. Our results showed that the photo-induced heating effect caused senescent cells to quickly undergo apoptosis and the synchronous immune response accelerated the clearance of senescent cells in vitro and in vivo. Therefore, this photoactivated speedy clearing strategy may provide an efficient way for the treatment of senescence-related diseases by eliminating senescent cells with biomaterials.

Ultra-small polydopamine nanomedicine-enabled antioxidation against senescence.

Senescence is a cellular response characterized by cells irreversibly stopping dividing and entering a state of permanent growth arrest. One of the underlying pathophysiological causes of senescence is the oxidative stress-induced damage, indicating that eliminating the reactive oxygen and nitrogen species (RONS) may be beneficial to prevent and/or alleviate senescence. Herein, we developed ultra-small polydopamine nanoparticles (UPDA NPs) with superoxide dismutase (SOD)/catalase (CAT) enzyme-mimic activities, featuring broad-spectrum RONS-scavenging capability for inducing cytoprotective effects against RONS-mediated damage. The engineered UPDA NPs can restore senescence-related renal function, tissue homeostasis, fur density, and motor ability in mice, potentially associated with the regulation of multiple genes involved in lipid metabolism, mitochondrial function, energy homeostasis, telomerase activity, neuroprotection, and inflammatory responses. Importantly, the dietary UPDA NPs can enhance the antioxidant capacity, improve the climbing ability, and prolong the lifespan of Drosophila. Notably, UPDA NPs possess excellent biocompatibility stemming from the ultra-small size, ensuring quick clearance out of the body. These findings reveal that UPDA NPs can delay aging through reducing oxidative stress and provide a paradigm and practical strategy for treating senescence and senescence-related diseases.

Precise Tumor Photothermal Therapy Guided and Monitored by Magnetic Resonance/Photoacoustic Imaging using A Safe and pH-Responsive Fe(III) Complex.

Photothermal agents with strong near infrared (NIR) optical absorbance and excellent biocompatibility and traceability are highly desired for precise photothermal therapy. This study reports the development of a dual-functional Fe3+ complex (Fe-ZDS) for imaging-guided, precise photothermal therapy of tumors. The complex has stable structure and obvious zwitterionic features, resulting in excellent biocompatibility and efficient renal clearance. The iron-dopa core structure renders the complex capable of generating magnetic resonance imaging (MRI) contrast, while synergistically exhibiting optical absorption in the red and NIR regions. Interestingly, the optical absorption of the complex is pH-sensitive, with significantly higher absorption intensity in a weakly acidic environment than in a neutral environment. Thus the complex can respond to acidic tumor stimuli and confine the energy of the laser to the tumor tissue. The MRI contrast and photoacoustic signal of the complex is taken advantage of to monitor the probe injection process and optimize the injection position and dosage for maximally covering the tumor tissue and assessing the activation of the complex in tumor tissues. The evolution of temperature inside the tissue during the laser irradiation is also monitored. Using Fe-ZDS as the theranostic probe, satisfactory treatment outcomes are achieved for photothermal therapy of tumors.

Endogenous Type I CRISPR-Cas: From Foreign DNA Defense to Prokaryotic Engineering.

Establishment of production platforms through prokaryotic engineering in microbial organisms would be one of the most efficient means for chemicals, protein, and biofuels production. Despite the fact that CRISPR (clustered regularly interspaced short palindromic repeats)-based technologies have readily emerged as powerful and versatile tools for genetic manipulations, their applications are generally limited in prokaryotes, possibly owing to the large size and severe cytotoxicity of the heterogeneous Cas (CRISPR-associated) effector. Nevertheless, the rich natural occurrence of CRISPR-Cas systems in many bacteria and most archaea holds great potential for endogenous CRISPR-based prokaryotic engineering. The endogenous CRISPR-Cas systems, with type I systems that constitute the most abundant and diverse group, would be repurposed as genetic manipulation tools once they are identified and characterized as functional in their native hosts. This article reviews the major progress made in understanding the mechanisms of invading DNA immunity by type I CRISPR-Cas and summarizes the practical applications of endogenous type I CRISPR-based toolkits for prokaryotic engineering.

Characterization and repurposing of the endogenous Type I-F CRISPR-Cas system of Zymomonas mobilis for genome engineering.

Application of CRISPR-based technologies in non-model microorganisms is currently very limited. Here, we reported efficient genome engineering of an important industrial microorganism, Zymomonas mobilis, by repurposing the endogenous Type I-F CRISPR-Cas system upon its functional characterization. This toolkit included a series of genome engineering plasmids, each carrying an artificial self-targeting CRISPR and a donor DNA for the recovery of recombinants. Through this toolkit, various genome engineering purposes were efficiently achieved, including knockout of ZMO0038 (100% efficiency), cas2/3 (100%), and a genomic fragment of >10 kb (50%), replacement of cas2/3 with mCherry gene (100%), in situ nucleotide substitution (100%) and His-tagging of ZMO0038 (100%), and multiplex gene deletion (18.75%) upon optimal donor size determination. Additionally, the Type I-F system was further applied for CRISPRi upon Cas2/3 depletion, which has been demonstrated to successfully silence the chromosomally integrated mCherry gene with its fluorescence intensity reduced by up to 88%. Moreover, we demonstrated that genome engineering efficiency could be improved under a restriction-modification (R-M) deficient background, suggesting the perturbance of genome editing by other co-existing DNA targeting modules such as the R-M system. This study might shed light on exploiting and improving CRISPR-Cas systems in other microorganisms for genome editing and metabolic engineering practices.

A pH-Sensitive Zwitterionic Iron Complex Probe with High Biocompatibility for Tumor-Specific Magnetic Resonance Imaging.

Accurate diagnosis of tumor characteristics, including its location and boundary, is of immense value to subsequent therapy. Activatable magnetic resonance imaging (MRI) contrast agents that respond to tumor-specific microenvironments, such as the redox state, pH, and enzyme activity, enable better mapping of tumor tissue. However, the practical application of most reported activatable agents is hampered by problems including potential toxicity, inefficient elimination, and slow activation. In this study, we developed a zwitterionic iron complex (Fe-ZDS) as a positive MRI contrast agent for tumor-specific imaging. Fe-ZDS could dissociate in weakly acidic solution rapidly, accompanied by clear longitudinal relaxivity (r1 ) enhancement, which enabled the complex to act as a pH-sensitive contrast agent for tumor-specific MR imaging. In vivo experiments showed that Fe-ZDS rapidly enhanced the tumor-to-normal contrast ratio by >40 %, which assisted in distinguishing the tumor boundary. Furthermore, Fe-ZDS circulated freely in the bloodstream and was excreted relatively safely via kidneys owing to its zwitterionic nature. Therefore, Fe-ZDS is an ideal candidate for a tumor-specific MRI contrast agent and holds considerable potential for clinical translation.

Gram-Scale Preparation of Iron Oxide Nanoparticles with Renal Clearance Properties for Enhanced T1-Weighted Magnetic Resonance Imaging.

Extremely small-sized iron oxide nanoparticles (ESIONs) have been accepted as a potential alternative to gadolinium-based contrast agents for enhanced T1-weighted MR imaging. Recently developed zwitterion-coated ESIONs showed a high T1 contrast power and efficient renal clearing ability, but the tedious preparation steps that required high-cost, unfriendly experimental conditions and a sophisticated phase transition process would likely hinder their clinical translation. Herein, we present a one-pot gram-scale synthesis of zwitterion-capped ultrasmall iron oxide nanoparticles (ZUIONs). The nanoparticles have a core size as small as 3.7 nm and display high colloidal stability in various buffers. The r1 relaxivity of 2.4 mM-1 s-1 and r2/r1 ratio as low as 2.2 at 1.0 T guarantee their application as effective T1 MRI contrast agents. In vivo studies showed that ZUIONs could induce a significant contrast enhancement in blood pool and be eliminated from the body mainly through the renal excretion pathway. The combined advantageous features including facile preparation, excellent biocompatibility, strong T1 MRI contrast effect, appropriate circulation time, and renal clearable property would render ZUIONs attractive for practical applications.