A self-assembling peptide targeting VEGF receptors to inhibit angiogenesis

Innovative Nanotechnology in Drug Delivery Systems for Advanced Treatment of Posterior Segment Ocular Diseases

Funduscopic diseases, including diabetic retinopathy (DR) and age-related macular degeneration (AMD), significantly impact global visual health, leading to impaired vision and irreversible blindness. Delivering drugs to the posterior segment of the eye remains a challenge due to the presence of multiple physiological and anatomical barriers. Conventional drug delivery methods often prove ineffective and may cause side effects. Nanomaterials, characterized by their small size, large surface area, tunable properties, and biocompatibility, enhance the permeability, stability, and targeting of drugs. Ocular nanomaterials encompass a wide range, including lipid nanomaterials, polymer nanomaterials, metal nanomaterials, carbon nanomaterials, quantum dot nanomaterials, and so on. These innovative materials, often combined with hydrogels and exosomes, are engineered to address multiple mechanisms, including macrophage polarization, reactive oxygen species (ROS) scavenging, and anti-vascular endothelial growth factor (VEGF). Compared to conventional modalities, nanomedicines achieve regulated and sustained delivery, reduced administration frequency, prolonged drug action, and minimized side effects. This study delves into the obstacles encountered in drug delivery to the posterior segment and highlights the progress facilitated by nanomedicine. Prospectively, these findings pave the way for next-generation ocular drug delivery systems and deeper clinical research, aiming to refine treatments, alleviate the burden on patients, and ultimately improve visual health globally.

Binding-induced fibrillogenesis peptide inhibits RANKL-mediated osteoclast activation against osteoporosis

Osteoporosis is primarily driven by an imbalance between bone resorption and formation, stemming from enhanced osteoclast activity during bone remodeling. At the crux of this mechanism lies the pivotal RANK-RANKL-OPG axis. In our study, we designed two binding-induced fibrillogenesis (BIF) peptides, namely BIFP and BIFY, targeting RANK and RANKL, respectively. These BIF peptides, with distinct hydrophilic and hydrophobic characteristics, assemble into nanoparticles (NPs) in aqueous solution. Through specific ligand-receptor interactions, these NPs efficiently target and bind to specific proteins, resulting in the formation of fibrous networks that effectively inhibit the RANK-RANKL associations. Experiments have confirmed the potent inhibitory effects of peptides on both osteoclast differentiation and function. Compared with the +RANKL controls, BIFP and BIFY demonstrated a more remarkable reduction in tartrate resistant acid phosphatase (TRAP)-positive cells, achieving an impressive decline of 82.8% and 70.7%, respectively. Remarkably, the administration of BIFP led to a substantial reduction in bone resorption pit area by 17.4%, compared to a significant increase of 92.4% in the +RANKL groups. In vivo experiments on an ovariectomized mouse model demonstrated that the BIFP treated group exhibited an impressive 2.6-fold elevation in bone mineral density and an astounding 4.0-fold enhancement in bone volume/total volume as against those of the PBS-treated group. Overall, BIF peptides demonstrate remarkable abilities to impede osteoclast differentiation, presenting promising prospects for the treatment of osteoporosis.

Entangling of Peptide Nanofibers Reduces the Invasiveness of SARS-CoV-2

The viral spike (S) protein on the surface of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to angiotensin-converting enzyme 2 (ACE2) receptors on the host cells, facilitating its entry and infection. Here, functionalized nanofibers targeting the S protein with peptide sequences of IRQFFKK, WVHFYHK and NSGGSVH, which are screened from a high-throughput one-bead one-compound screening strategy, are designed and prepared. The flexible nanofibers support multiple binding sites and efficiently entangle SARS-CoV-2, forming a nanofibrous network that blocks the interaction between the S protein of SARS-CoV-2 and the ACE2 on host cells, and efficiently reduce the invasiveness of SARS-CoV-2. In summary, nanofibers entangling represents a smart nanomedicine for the prevention of SARS-CoV-2.

In Vivo Anchoring Bis-Pyrene Probe for Molecular Imaging of Early Gastric Cancer by Endoscopic Techniques

With the development of blue laser endoscopy (BLE) technique, it's often used to diagnose early gastric cancer (EGC) by the morphological changes of blood vessels through BLE. However, EGC is still not obvious to identify, resulting in a high rate of missed diagnosis. Molecular imaging can show the changes in early tumors at molecular level, which provides a possibility for diagnosing EGC. Therefore, developing a probe that visually monitors blood vessels of EGC under BLE is particularly necessary. Herein, a bis-pyrene (BP) based nanoprobe (BP-FFVLK-(PEG)-RGD, M1 ) is designed, which can target angiogenesis and self-assemble into fibers in situ, resulting in stable and long-term retention in tumor. Moreover, M1 probe can emit yellow-green fluorescence for imaging under BLE. M1 probe is confirmed to steadily remain in tumor for up to 96 hours in mice transplanted subcutaneously. In addition, the M1 probe is able to target angiogenesis for molecular imaging of isolated human gastric cancer tissue under BLE. Finally, M1 probe i.v. injected into primary gastric cancer model rabbits successfully highlighted the tumor site under BLE, which is confirmed by pathological analysis. It's the first time to develop a probe for diagnosing EGC by visualizing angiogenesis under BLE, showing great clinical significance.

Near-infrared-IIb emitting single-atom catalyst for imaging-guided therapy of blood-brain barrier breakdown after traumatic brain injury

The blood-brain barrier breakdown, as a prominent feature after traumatic brain injury, always triggers a cascade of biochemical events like inflammatory response and free radical-mediated oxidative damage, leading to neurological dysfunction. The dynamic monitoring the status of blood-brain barrier will provide potent guidance for adopting appropriate clinical intervention. Here, we engineer a near-infrared-IIb Ag₂Te quantum dot-based Mn single-atom catalyst for imaging-guided therapy of blood-brain barrier breakdown of mice after traumatic brain injury. The dynamic change of blood-brain barrier, including the transient cerebral hypoperfusion and cerebrovascular damage, could be resolved with high spatiotemporal resolution (150 ms and ~ 9.6 µm). Notably, the isolated single Mn atoms on the surface of Ag₂Te exhibited excellent catalytic activity for scavenging reactive oxygen species to alleviate neuroinflammation in brains. The timely injection of Mn single-atom catalyst guided by imaging significantly promoted the reconstruction of blood-brain barrier and recovery of neurological function after traumatic brain injury.

An injectable thermosensitive hydrogel for dual delivery of diclofenac and Avastin® to effectively suppress inflammatory corneal neovascularization

Corneal neovascularization (CNV) is a sequela of anterior segment inflammation, which could lead to vision impairment and even blindness. In the present study, the dual delivery of anti-inflammatory agent (i.e., diclofenac; DIC) and anti-VEGF antibody (i.e., Avastin®; Ava) by the thermosensitive hydrogel (Poly(dl-lactide)-poly(ethylene glycol)-poly(dl-lactide); PDLLA-PEG-PDLLA) is expected to effectively inhibit CNV via their synergistic effects. The optimal DIC micelles were formulated and then mixed with Ava and PDLLA-PEG-PDLLA aqueous solution to generate various DIC@Ava-loaded hydrogels. The co-encapsulation of DIC micelles and Ava did not influence the gelling behavior of the system, and the resulting DIC@Ava-loaded hydrogel provided sustained drug release of both DIC and Ava without compromising their pharmacological activity over 19 days. As indicated by in vitro cytotoxicity and in vivo ocular biocompatibility test, the proposed PDLLA-PEG-PDLLA hydrogel caused minimal cytotoxicity against all tested cell lines at a polymeric concentration ranging from 0.05 mg/mL to 0.8 mg/mL and demonstrated good ocular biocompatibility after a single subconjunctival injection. Using the rabbit CNV model, we documented the superior anti-angiogenic effects of the DIC@Ava-loaded hydrogel over Ava alone medication (treatment with Ava solution and Ava-loaded hydrogel) due to synergistic effects of anti-VEGF and anti-inflammatory action. Overall, the proposed DIC@Ava-loaded hydrogel might be a powerful strategy to reduce CNV.

Emerging prospects of protein/peptide-based nanoassemblies for drug delivery and vaccine development

Proteins have been widely used in the biomedical field because of their well-defined architecture, accurate molecular weight, excellent biocompatibility and biodegradability, and easy-to-functionalization. Inspired by the wisdom of nature, increasing proteins/peptides that possess self-assembling capabilities have been explored and designed to generate nanoassemblies with unique structure and function, including spatially organized conformation, passive and active targeting, stimuli-responsiveness, and high stability. These characteristics make protein/peptide-based nanoassembly an ideal platform for drug delivery and vaccine development. In this review, we focus on recent advances in subsistent protein/peptide-based nanoassemblies, including protein nanocages, virus-like particles, self-assemblable natural proteins, and self-assemblable artificial peptides. The origin and characteristics of various protein/peptide-based assemblies and their applications in drug delivery and vaccine development are summarized. In the end, the prospects and challenges are discussed for the further development of protein/peptide-based nanoassemblies.

Ca2+ accelerates peptide fibrillogenesis via a heterogeneous secondary nucleation pathway

A binding-induced fibrillogenesis (BIF) peptide mimics the fibrillogenesis of fibronectin, forming fibrous networks for disease theranostics. However, the mechanism of fast fibrillogenesis of the BIF peptide remains unclear. In this study, the fibrillogenesis processes of the BIF peptide in the absence and presence of receptors, i.e. Ca²⁺, are carefully studied. The BIF peptide, lauric acid-FFVLK-HSDVHK (LAFH) can self-assemble into nanoparticles (NPs) in solution and further transform into a fibrous structure, the fibrillogenesis of which could be accelerated by the addition of Ca²⁺. In detail, the fibrillogenesis of LAFH NPs without Ca²⁺ is achieved through a nucleation-elongation mechanism, in which homogeneous secondary nucleation is involved, followed by detachment of the newly formed fibers from pre-formed nanofibers (NFs). The fibrillogenesis of LAFH NPs in the presence of Ca²⁺ starts with an Ostwald ripening process, followed by a heterogeneous secondary nucleation, in which LAFH NPs bind to pre-formed LAFH NFs via Ca²⁺. The phenomenon of heterogeneous secondary nucleation including the attachment and shape change of LAFH NPs on pre-formed LAFH NFs is first revealed by TEM observation. These findings contribute to the understanding of the fast BIF process, supporting the mechanism study at the cellular level.

Self-assembling and cellular distribution of a series of transformable peptides

Transformable peptides (TPs) are biomedical materials with unique structures and diverse functionalities that have drawn great interest in material science and nanomedicine. Here, we design a series of TPs with...

Stimuli Responsive Nitric Oxide-Based Nanomedicine for Synergistic Therapy

Gas therapy has received widespread attention from the medical community as an emerging and promising therapeutic approach to cancer treatment. Among all gas molecules, nitric oxide (NO) was the first one to be applied in the biomedical field for its intriguing properties and unique anti-tumor mechanisms which have become a research hotspot in recent years. Despite the great progress of NO in cancer therapy, the non-specific distribution of NO in vivo and its side effects on normal tissue at high concentrations have impaired its clinical application. Therefore, it is important to develop facile NO-based nanomedicines to achieve the on-demand release of NO in tumor tissue while avoiding the leakage of NO in normal tissue, which could enhance therapeutic efficacy and reduce side effects at the same time. In recent years, numerous studies have reported the design and development of NO-based nanomedicines which were triggered by exogenous stimulus (light, ultrasound, X-ray) or tumor endogenous signals (glutathione, weak acid, glucose). In this review, we summarized the design principles and release behaviors of NO-based nanomedicines upon various stimuli and their applications in synergistic cancer therapy. We also discuss the anti-tumor mechanisms of NO-based nanomedicines in vivo for enhanced cancer therapy. Moreover, we discuss the existing challenges and further perspectives in this field in the aim of furthering its development.

A Monotargeting Peptidic Network Antibody Inhibits More Receptors for Anti-Angiogenesis

The overexpression of growth factors and receptors on neovascular endothelial cells (ECs) and their binding may promote the abnormal growth of new blood vessels, leading to corneal neovascularization (CNV). Normally, monoclonal antibodies may bind and block only one growth factor or receptor, such as bevacizumab binding and blocking vascular endothelial growth factor (VEGF). Herein, we develop a monotargeting peptidic network antibody (pepnetibody) that blocks multiple receptors on the membrane of ECs through forming a fibrous network and ultimately achieves high-efficient treatment of CNV. The pepnetibody could bind to integrin α_vβ₃ in particulate formulation and in situ fibrillogenesis on ECs, mimicking the process of fibronectin fibrillogenesis on the cell membrane. The in situ formed peptidic network could firmly block integrin and cover other angiogenesis-related receptors, such as VEGF receptor-2 and neuropilin-1, exhibiting competitive efficacy of antiangiogenesis compared with traditional monoclonal antibody bevacizumab with 97.7 times lower dose.

Binding-Induced Fibrillogenesis Peptides Recognize and Block Intracellular Vimentin Skeletonization against Breast Cancer

Life is recognized as a sophisticated self-assembling material system. Cancer involves the overexpression and improper self-assembly of proteins, such as cytoskeleton protein vimentin, an emerging target related to tumor metastasis. Herein, we design a binding-induced fibrillogenesis (BIF) peptide that in situ forms fibrous networks, blocking the improper self-assembly of vimentin against cancer. The BIF peptide can bind to vimentin and subsequently perform fibrillogenesis to form fibers on vimentin. The resultant peptide fibrous network blocks vimentin skeletonization and inhibits the migration and invasion of tumor cells. In mouse models of tumor metastasis, the volume of tumor and the number of lung metastases are markedly decreased. Moreover, the efficacy of BIF peptide (5 mg/kg) is much higher than small molecular antimetastasis drug withaferin A (5 mg/kg) as a standard, indicating that the BIF peptide shows advantages over small molecular inhibitors in blocking the intracellular protein self-assembly.

In situ self-assembled peptide nanofibers for cancer theranostics

Self-assembled nanofibers hold tremendous promise for cancer theranostics owing to their in situ assembly, spatiotemporal responsiveness, and diverse bioactivity. Herein, this review summarizes the recent advances of self-assembled peptide nanofibers and their applications in biological systems, focusing on the dynamic process of capturing cancer cells from the outside-in. (1) In situ self-assembly in response to pathological or physiological changes. (2) Diverse functions at different locations of tumors, such as forming thrombus in tumor vasculature, constructing a barrier on the cancer cell membrane, and disrupting the cancer organelles. Of note, with the assembly/aggregation induced residence (AIR) effect, the nanofibers could form a drug depot in situ for sustained release of chemotherapeutic drugs to increase their local concentration and prolong the residence time. Finally, perspectives toward future directions and challenges are presented to further understand and expand this exciting field.

Monotherapy and Combination Therapy Using Anti-Angiogenic Nanoagents to Fight Cancer

Anti-angiogenic therapy, targeting vascular endothelial cells (ECs) to prevent tumor growth, has been attracting increasing attention in recent years, beginning with bevacizumab (Avastin) through its Phase II/III clinical trials on solid tumors. However, these trials showed only modest clinical efficiency; moreover, anti-angiogenic therapy may induce acquired resistance to the drugs employed. Combining advanced drug delivery techniques (e.g., nanotechnology) or other therapeutic strategies (e.g., chemotherapy, radiotherapy, phototherapy, and immunotherapy) with anti-angiogenic therapy results in significantly synergistic effects and has opened a new horizon in fighting cancer. Herein, clinical difficulties in using traditional anti-angiogenic therapy are discussed. Then, several promising applications of anti-angiogenic nanoagents in monotherapies and combination therapies are highlighted. Finally, the challenges and perspectives of anti-angiogenic cancer therapy are summarized. A useful introduction to anti-angiogenic strategies, which may significantly improve therapeutic outcomes, is thus provided.