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

In Situ Biomimetic Glycocalyx Layer Protects Endothelial Damage in Xenotransplantation

Xenotransplantation offers a transformative solution to the global organ shortage crisis. However, the survival of xenografts remains limited despite various proposed strategies. In this study, we present an endothelial cell protection strategy that extends graft survival through the in situ construction of biomimetic glycan-enriched nanofibers. These biomimetic glycan-enriched molecules specifically target integrin αvβ3 and form a polysaccharide-structured nanofiber network on the vascular endothelial surface. This network protects endothelial cells without compromising their normal physiological functions. The constructed biomimetic glycan-enriched layer significantly increased the xenograft survival by 1.64-fold compared to the untreated groups. This work introduces a novel strategy to enhance the survival of heart xenografts.

Progress in Nanotechnology for Treating Ocular Surface Chemical Injuries: Reflecting on Advances in Ophthalmology

Ocular surface chemical injuries often result in permanent visual impairment and necessitate complex, long-term treatments. Immediate and extensive irrigation serves as the first-line intervention, followed by various therapeutic protocols applied throughout different stages of the condition. To optimize outcomes, conventional regimens increasingly incorporate biological agents and surgical techniques. In recent years, nanotechnology has made significant strides, revolutionizing the management of ocular surface chemical injuries by enabling sustained drug release, enhancing treatment efficacy, and minimizing side effects. This review provides a comprehensive analysis of the etiology, epidemiology, classification, and conventional therapies for ocular chemical burns, with a special focus on nanotechnology-based drug delivery systems in managing ocular surface chemical injuries. Twelve categories of nanocarrier platforms are examined, including liposomes, nanoemulsions, nanomicelles, nanowafers, nanostructured lipid carriers, nanoparticles, hydrogels, dendrimers, nanocomplexes, nanofibers, nanozymes, and nanocomposite materials, highlighting their advantages in targeted delivery, biocompatibility, and improved healing efficacy. Additionally, current challenges and limitations in the field are discussed and the future potential of nanotechnology in treating ocular diseases is explored. This review presents the most extensive examination of this topic to date, aiming to link recent advancements with broader therapeutic strategies.

Self-Assembly in Living Cells: Bottom-Up Syntheses in Natural Factory

In situ self-assembly in living systems is referred to as the processes that regulate assembly by stimuli-responsive reactions at target sites under physiological conditions. Due to the advantages of precisely forming well-defined nanostructures at pathological lesions, in situ-formed assemblies with tailored bioactivity are promising for the development of next-generation biomedical agents. In this Perspective, we summarize the progress of in situ self-assembly of peptides in living cells with an emphasis on the state-of-the-art strategies regulating assembly processes, establishing complexity within assembly systems, and exploiting their applications in biomedicines. We also provide our forward conceiving perspectives on the challenges in the development of in situ assembly in living cells to demonstrate its great potential in creating biomaterials for healthcare in the future.

Enhancing the Inhibition of Corneal Neovascularization Efficacy by Self-Assembled into Supramolecular Hydrogel of Anti-Angiogenic Peptide

Background

Corneal neovascularization (CNV) is a common eye disease that leads to blindness. New treatment strategies are urgently needed due to the limitations of current treatment methods.

Methods

We report the synthesis of peptide Nap-FFEEPCAIWF ( Comp.3 ) via chemical conjugation of Nap-FFEE ( Comp.2 ) to antiangiogenic peptide PCAIWF (Comp.1). Comp.3 self-assembled into a hydrogel ( gel of 3 ) composed of nanofibers, which enhanced the antiangiogenic function of the epitope.

Results

We developed a novel peptide with an amphiphilic framework, Comp.3 , which could self-assemble into a supramolecular hydrogel with a well-ordered nanofiber structure. The nanofibers exhibited good biocompatibility with corneal epithelial cells, presenting a promising strategy to enhance the efficacy of free peptide-based drugs in the treatment of ocular vascular diseases, such as CNV and other angiogenesis-related diseases.

Conclusion

Nap-FFEEPCAIWF nanofibers provide an alternative approach to enhancing the therapeutic efficiency of free peptide-based drugs against ocular vascular diseases.

An in-situ peptide-antibody self-assembly to block CD47 and CD24 signaling enhances macrophage-mediated phagocytosis and anti-tumor immune responses

Targeted immunomodulation for reactivating innate cells, especially macrophages, holds great promise to complement current adaptive immunotherapy. Nevertheless, there is still a lack of high-performance therapeutics for blocking macrophage phagocytosis checkpoint inhibitors in solid tumors. Herein, a peptide-antibody combo-supramolecular in situ assembled CD47 and CD24 bi-target inhibitor (PAC-SABI) is described, which undergoes biomimetic surface propagation on cancer cell membranes through ligand-receptor binding and enzyme-triggered reactions. By simultaneously blocking CD47 and CD24 signaling, PAC-SABI enhances the phagocytic ability of macrophages in vitro and in vivo, promoting anti-tumor responses in breast and pancreatic cancer mouse models. Moreover, building on the foundation of PAC-SABI-induced macrophage repolarization and increased CD8+ T cell tumor infiltration, sequential anti-PD-1 therapy further suppresses 4T1 tumor progression, prolonging survival rate. The in vivo construction of PAC-SABI-based nano-architectonics provides an efficient platform for bridging innate and adaptive immunity to maximize therapeutic potency.

Integrin αVβ3 antagonist-c(RGDyk) peptide attenuates the progression of ossification of the posterior longitudinal ligament by inhibiting osteogenesis and angiogenesis

BACKGROUND

Ossification of the posterior longitudinal ligament (OPLL), an emerging heterotopic ossification disease, causes spinal cord compression, resulting in motor and sensory dysfunction. The etiology of OPLL remains unclear but may involve integrin αVβ3 regulating the process of osteogenesis and angiogenesis. In this study, we focused on the role of integrin αVβ3 in OPLL and explored the underlying mechanism by which the c(RGDyk) peptide acts as a potent and selective integrin αVβ3 inhibitor to inhibit osteogenesis and angiogenesis in OPLL.

METHODS

OPLL or control ligament samples were collected in surgery. For OPLL samples, RNA-sequencing results revealed activation of the integrin family, particularly integrin αVβ3. Integrin αVβ3 expression was detected by qPCR, Western blotting, and immunohistochemical analysis. Fluorescence microscopy was used to observe the targeted inhibition of integrin αVβ3 by the c(RGDyk) peptide on ligaments fibroblasts (LFs) derived from patients with OPLL and endothelial cells (ECs). The effect of c(RGDyk) peptide on the ossification of pathogenic LFs was detected using qPCR, Western blotting. Alkaline phosphatase staining or alizarin red staining were used to test the osteogenic capability. The effect of the c(RGDyk) peptide on angiogenesis was determined by EC migration and tube formation assays. The effects of the c(RGDyk) peptide on heterotopic bone formation were evaluated by micro-CT, histological, immunohistochemical, and immunofluorescence analysis in vivo.

RESULTS

The results indicated that after being treated with c(RGDyk), the osteogenic differentiation of LFs was significantly decreased. Moreover, the c(RGDyk) peptide inhibited the migration of ECs and thus prevented the nutritional support required for osteogenesis. Furthermore, the c(RGDyk) peptide inhibited ectopic bone formation in mice. Mechanistic analysis revealed that c(RGDyk) peptide could inhibit osteogenesis and angiogenesis in OPLL by targeting integrin αVβ3 and regulating the FAK/ERK pathway.

CONCLUSIONS

Therefore, the integrin αVβ3 appears to be an emerging therapeutic target for OPLL, and the c(RGDyk) peptide has dual inhibitory effects that may be valuable for the new therapeutic strategy of OPLL.

Inhibition of platelet adhesion to exposed subendothelial collagen by steric hindrance with blocking peptide nanoparticles

The inhibition of platelet adhesion to collagen in exposed vessels represents an innovative approach to the treatment of atherosclerosis and thrombosis. This study aimed to engineer peptide-based nanoparticles that prevent platelet binding to subendothelial collagen by engaging with collagen with high affinity. We examined the interactions between integrin α2/ glycoprotein VI/ von Willebrand factor A3 domain and collagen, as well as between the synthesized peptide nanoparticles and collagen, utilizing molecular dynamics simulations and empirical assays. Our findings indicated that the bond between von Willebrand factor and collagen was more robust. Specifically, the sequences SITTIDV, VDVMQRE, and YLTSEMH in von Willebrand factor were identified as essential for its attachment to collagen. Based on these sequences, three peptide nanoparticles were synthesized (BPa: Capric-GNNQQNYK-SITTIDV, BPb: Capric-GNNQQNYK-VDVMQRE, BPc: Capric-GNNQQNYK-YLTSEMH), each displaying significant affinity towards collagen. Of these, the BPa nanoparticles exhibited the most potent interaction with collagen, leading to a 75% reduction in platelet adhesion.

Cell Membrane as A Promising Therapeutic Target: From Materials Design to Biomedical Applications

The cell membrane is a crucial component of cells, protecting their integrity and stability while facilitating signal transduction and information exchange. Therefore, disrupting its structure or impairing its functions can potentially cause irreversible cell damage. Presently, the tumor cell membrane is recognized as a promising therapeutic target for various treatment methods. Given the extensive research focused on cell membranes, it is both necessary and timely to discuss these developments, from materials design to specific biomedical applications. This review covers treatments based on functional materials targeting the cell membrane, ranging from well-known membrane-anchoring photodynamic therapy to recent lysosome-targeting chimaeras for protein degradation. The diverse therapeutic mechanisms are introduced in the following sections: membrane-anchoring phototherapy, self-assembly on the membrane, in situ biosynthesis on the membrane, and degradation of cell membrane proteins by chimeras. In each section, we outline the conceptual design or general structure derived from numerous studies, emphasizing representative examples to understand advancements and draw inspiration. Finally, we discuss some challenges and future directions in membrane-targeted therapy from our perspective. This review aims to engage multidisciplinary readers and encourage researchers in related fields to advance the fundamental theories and practical applications of membrane-targeting therapeutic agents.

Nanofibers in Organelles: From Structure Design to Biomedical Applications

Nanofibers are one of the most important morphologies of molecular self-assemblies, the formation of which relies on the diverse intermolecular interactions of fibrous-forming units. In the past decade, rapid advances have been made in the biomedical application of nanofibers, such as bioimaging and tumor treatment. An important topic to be focused on is not only the nanofiber formation mechanism but also where it forms, because different destinations could have different influences on cells and its formation could be triggered by unique stimuli in organelles. It is therefore necessary and timely to summarize the nanofibers assembled in organelles. This minireview discusses the formation mechanism, triggering strategies, and biomedical applications of nanofibers, which may facilitate the rational design of nanofibers, improve our understanding of the relationship between nanofiber properties and organelle characteristics, allow a comprehensive recognition of organelles affected by materials, and enhance the therapeutic efficiency of nanofibers.

A Biomimetic Peptide Functions as Specific Extracellular Matrix for Quiescence of Stem Cells against Intervertebral Disc Degeneration

Maintaining quiescence of stem cells is a potential way to decrease cell nutrition demand for restoring the organization. Herein, a biomimetic peptide to maintain quiescence of stem cells through C-X-C motif chemokine ligand 8 (CXCL8)-C-X-C motif chemokine receptor 1 (CXCR1) pathway against intervertebral disc degeneration (IVDD) is developed. First, it is confirmed that quiescence can be induced via inhibiting phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway in nucleus pulposus stem cells (NPSCs). Meanwhile, it is well known that CXCR1, a chemokine receptor, can be targeted by CXCL8, resulting in cell proliferation via activating PI3K/Akt/mTOR pathway. Second, a biomimetic peptide (OAFF) that can bind to CXCR1 and form fibrous networks on NPSCs, mimicking extracellular matrix formation is developed. The multivalent effect and long-term binding to CXCR1 on NPSCs of OAFF fibers offer forcefully competitive inhibition with natural CXCL8, which induces NPSCs quiescence and ultimately overcomes obstacle in intradiscal injection therapy. In rat caudal disc puncture model, OAFF nanofibers still maintain at 5 weeks after operation and inhibit degeneration process of intervertebral disc in terms of histopathology and imageology. In situ fibrillogenesis of biomimetic peptide on NPSCs provides promising stem cells for intradiscal injection therapy against IVDD.

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.

A peptidic network antibody inhibits both angiogenesis and inflammatory response

Corneal neovascularization (CNV) is a global threat to human health. Traditional anti-angiogenesis agent may have therapy effect, while the inflammation in disease area remains unsolved. Herein, we reported two binding-induced fibrillogenesis (BIF) peptides as peptidic network antibodies for high-efficient and long-lasting anti-angiogenesis with reduced inflammatory response. BIF peptides could self-assemble into nanoparticles and further perform BIF behavior through binding Ca2+. In vitro, the migration of integrin αvβ3 highly expressed endothelial cells was inhibited by BIF peptides. In vivo, one BIF peptide (0.012 mg/Kg) exhibited higher anti-angiogenesis effect than monoclonal antibody bevacizumab (0.96 mg/Kg) in a CNV rabbit model on day 14, despite that the dose of BIF was only 1.3% of bevacizumab. Meanwhile, the inflammatory response, such as PI3 kinase/Akt pathway in CNV was successfully inhibited as well. The peptidic network antibody could block integrin αvβ3 via a long-term retention mode, which led to long-term therapeutic effect. The study provides BIF peptides as promising therapeutic agents for both anti-angiogenesis and reduced inflammatory response.

In situ stimulus-responsive self-assembled nanomaterials for drug delivery and disease treatment

The individual motifs that respond to specific stimuli for the self-assembly of nanomaterials play important roles. In situ constructed nanomaterials are formed spontaneously without human intervention and have promising applications in bioscience. However, due to the complex physiological environment of the human body, designing stimulus-responsive self-assembled nanomaterials in vivo is a challenging problem for researchers. In this article, we discuss the self-assembly principles of various nanomaterials in response to the tissue microenvironment, cell membrane, and intracellular stimuli. We propose the applications and advantages of in situ self-assembly in drug delivery and disease diagnosis and treatment, with a focus on in situ self-assembly at the lesion site, especially in cancer. Additionally, we introduce the significance of introducing exogenous stimulation to construct self-assembly in vivo. Based on this foundation, we put forward the prospects and possible challenges in the field of in situ self-assembly. This review uncovers the relationship between the structure and properties of in situ self-assembled nanomaterials and provides new ideas for innovative drug molecular design and development to solve the problems in the targeted delivery and precision medicine.

Semaphorin3A Exacerbates Cardiac Microvascular Rarefaction in Pressure Overload-Induced Heart Disease

Microvascular endothelial cells (MiVECs) impair angiogenic potential, leading to microvascular rarefaction, which is a characteristic feature of chronic pressure overload-induced cardiac dysfunction. Semaphorin3A (Sema3A) is a secreted protein upregulated in MiVECs following angiotensin II (Ang II) activation and pressure overload stimuli. However, its role and mechanism in microvascular rarefaction remain elusive. The function and mechanism of action of Sema3A in pressure overload-induced microvascular rarefaction, is explored, through an Ang II-induced animal model of pressure overload. RNA sequencing, immunoblotting analysis, enzyme-linked immunosorbent assay, quantitative reverse transcription polymerase chain reaction (qRT-PCR), and immunofluorescence staining results indicate that Sema3A is predominantly expressed and significantly upregulated in MiVECs under pressure overload. Immunoelectron microscopy and nano-flow cytometry analyses indicate small extracellular vesicles (sEVs), with surface-attached Sema3A, to be a novel tool for efficient release and delivery of Sema3A from the MiVECs to extracellular microenvironment. To investigate pressure overload-mediated cardiac microvascular rarefaction and cardiac fibrosis in vivo, endothelial-specific Sema3A knockdown mice are established. Mechanistically, serum response factor (transcription factor) promotes the production of Sema3A; Sema3A-positive sEVs compete with vascular endothelial growth factor A to bind to neuropilin-1. Therefore, MiVECs lose their ability to respond to angiogenesis. In conclusion, Sema3A is a key pathogenic mediator that impairs the angiogenic potential of MiVECs, which leads to cardiac microvascular rarefaction in pressure overload-induced heart disease.

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.