Cell-Penetrating Peptide Conjugated Au Nanoclusters Selectively Suppress Refractory Lymphoma Cells via Targeting Both Canonical and Noncanonical NF-κB Signaling Pathways

Hybridization Design and High-Throughput Screening of Peptides with Immunomodulatory and Antioxidant Activities

With the increasing recognition of the role of immunomodulation and oxidative stress in various diseases, designing peptides with both immunomodulatory and antioxidant activities has emerged as a promising therapeutic strategy. In this study, a hybridization design was applied as a powerful method to obtain multifunctional peptides. A total of 40 peptides with potential immunomodulatory and antioxidant activities were designed and screened. First, molecular docking was employed to screen peptides with a high binding affinity to MD2, a key receptor protein in the NFκB immune pathway. For the in vitro high-throughput screening, we constructed a reporter gene-based stable cell line, IPEC-J2-Lucia ARE cells, which was subsequently used to screen peptides with antioxidant activity. Furthermore, the biocompatibility, immunomodulatory, and antioxidant activities of these peptides were assessed. Among the candidates, the hybrid peptide VA exhibited the strongest immune-enhancing activity through the activation of the NF-κB pathway and significant antioxidant activity via the Nrf2-ARE pathway. Additionally, VA demonstrated protective effects against H2O2-induced oxidative damage in HepG2 cells. This study not only demonstrates the potential of peptide hybridization, but also develops a screening platform for multifunctional peptides. It provides a new tool for the treatment of autoimmune diseases and oxidative stress-related diseases.

Targeted Gold Nanoclusters for Synergistic High-Risk Neuroblastoma Therapy through Noncanonical Ferroptosis

Children with extracranial high-risk neuroblastoma (NB) have a poor prognosis due to resistance against apoptosis. Recently, ferroptosis, another form of programmed cell death, has been tested in clinical trials for high-risk NB; however, drug resistance and side effects have also been observed. Here, we find that the gold element in gold nanoclusters can significantly affect iron metabolism and sensitize high-risk NB cells to ferroptosis. Accordingly, we developed a gold nanocluster conjugated with a modified NB-targeting peptide. This gold nanocluster, namely, NANT, shows excellent NB targeting efficiency and dramatically promotes ferroptosis. Surprisingly, this effect is exerted by elevating the noncanonical ferroptosis pathway, which is dependent on heme oxygenase-1-regulated Fe(II) accumulation. Furthermore, NANT dramatically inhibits the growth of high-risk NB in both tumor spheroid and xenograft models by promoting noncanonical ferroptosis evidenced by enhanced intratumoral Fe(II) and heme oxygenase-1. Importantly, this strategy shows excellent cardiosafety, offering a promising strategy to overcome ferroptosis resistance for the efficient and safe treatment of children with high-risk neuroblastoma.

Beyond Transduction: Anti-Inflammatory Effects of Cell Penetrating Peptides

One of the bottlenecks to bringing new therapies to the clinic has been a lack of vectors for delivering novel therapeutics in a targeted manner. Cell penetrating peptides (CPPs) have received a lot of attention and have been the subject of numerous developments since their identification nearly three decades ago. Known for their transduction abilities, they have generally been considered inert vectors. In this review, we present a schema for their classification, highlight what is known about their mechanism of transduction, and outline the existing literature as well as our own experience, vis a vis the intrinsic anti-inflammatory properties that certain CPPs exhibit. Given the inflammatory responses associated with viral vectors, CPPs represent a viable alternative to such vectors; furthermore, the anti-inflammatory properties of CPPs, mostly through inhibition of the NF-κB pathway, are encouraging. Much more work in relevant animal models, toxicity studies in large animal models, and ultimately human trials are needed before their potential is fully realized.

The roles of templates consisting of amino acids in the synthesis and application of gold nanoclusters

Gold nanoclusters (AuNCs) with low toxicity, high photostability, and facile synthesis have attracted great attention. The ligand is of great significance in stabilizing AuNCs and regulating their properties. Ligands consisting of amino acids (proteins and peptides) are an ideal template for synthesizing applicative AuNCs due to their inherent bioactivity, biocompatibility, and accessibility. In this review, we summarize the correlation of the template consisting of amino acids with the properties of AuNCs by analyzing different peptide sequences. The selection of amino acids can regulate the fluorescence excitation/emission and intensity, size, cell uptake, and light absorption. By analyzing the role played by AuNCs stabilized by proteins and peptides in the application, universal rules and detailed performances of sensors, antibacterial agents, therapeutic reagents, and light absorbers are reviewed. This review can guide the template design and application of AuNCs when selecting proteins and peptides as ligands.

Different Targeting Ligands-Mediated Drug Delivery Systems for Tumor Therapy

Traditional tumor treatments have the drawback of harming both tumor cells and normal cells, leading to significant systemic toxic side effects. As a result, there is a pressing need for targeted drug delivery methods that can specifically target cells or tissues. Currently, researchers have made significant progress in developing targeted drug delivery systems for tumor therapy using various targeting ligands. This review aims to summarize recent advancements in targeted drug delivery systems for tumor therapy, focusing on different targeting ligands such as folic acid, carbohydrates, peptides, aptamers, and antibodies. The review also discusses the advantages, challenges, and future prospects of these targeted drug delivery systems.

Multiscale Bioresponses of Metal Nanoclusters

Metal nanoclusters (NCs) are well-recognized novel nano-agents that hold great promise for applications in nanomedicine because of their ultrafine size, low toxicity, and high renal clearance. As foreign substances, however, an in-depth understanding of the bioresponses to metal NCs is necessary but is still far from being realized. Herein, this review is deployed to summarize the biofates of metal NCs at various biological levels, emphasizing their multiscale bioresponses at the molecular, cellular, and organismal levels. In the parts-to-whole schema, the interactions between biomolecules and metal NCs are discussed, presenting typical protein-dictated nano-bio interfaces, hierarchical structures, and in vivo trajectories. Then, the accumulation, internalization, and metabolic evolution of metal NCs in the cellular environment and as-imparted theranostic functionalization are demonstrated. The organismal metabolism and transportation processes of the metal NCs are subsequently distilled. Finally, this review ends with the conclusions and perspectives on the outstanding issues of metal NC-mediated bioresponses in the near future. This review is expected to provide inspiration for tailoring the customization of metal NC-based nano-agents to meet practical requirements in different sectors of nanomedicine.

Colon-Accumulated Gold Nanoclusters Alleviate Intestinal Inflammation and Prevent Secondary Colorectal Carcinogenesis via Nrf2-Dependent Macrophage Reprogramming

Inflammatory bowel disease (IBD) is one of the main factors leading to colitis-associated colorectal cancer (CAC). Therefore, it is critical to develop an effective treatment for IBD to prevent secondary colorectal carcinogenesis. M2 macrophages play crucial roles in the resolution phase of intestinal inflammation. However, traditional drugs rarely target intestinal M2 macrophages, and they are not easily cleared. Gold nanoclusters are known for their in vivo safety and intrinsic biomedical activities. In this study, a glutathione-protected gold nanocluster is synthesized and evaluated, namely, GA. Interestingly, GA specifically accumulates in the colon during IBD. Furthermore, GA not only promotes M2 differentiation of IL-4-treated peritoneal macrophages but also reprograms macrophage polarization from M1 to M2 in a pro-inflammatory environment. Mechanistically, this regulatory effect is exerted through activating the antioxidant Nrf2 signaling pathway, but not traditional STAT6. When applied in IBD mice, we found that GA elevates M2 macrophages and alleviates IBD in an Nrf2-dependent manner, evidenced by the abolished therapeutic effect upon Nrf2 inhibitor treatment. Most importantly, GA administration significantly suppresses AOM/DSS-induced CAC, without causing obvious tissue damage, providing critical evidence for the potential application of gold nanoclusters as nanomedicine for the treatment of IBD and CAC.