A specific affinity cyclic peptide enhances the adhesion, expansion and proliferation of rat bone mesenchymal stem cells on β‑tricalcium phosphate scaffolds

Live MSCs Characterizer Displays Stemness and Differentiation Using Colorful LV-cp Biosensors

Mesenchymal stem cells (MSCs) have garnered significant attention in biomedical research due to their accessibility and remarkable differentiation potential. However, the lack of efficient and convenient living cell monitoring methods limits their widespread application in tissue engineering and stem cell therapy. Therefore, we present progress in the development of a novel series of fluorescent protein (FP) sensors based on turn-on fluorescent protein biosensors (Turn-on FPBs), termed the LV-cp biosensor system (novel live cell permuted fluorescent protein biosensors). Utilizing phage display technology to screen for affinity peptides specifically targeting MSCs and chondrocytes, the LV-cp were engineered by subcloning these peptides into permuted fluorescent proteins, thereby integrating the fluorescence activation mechanism with the affinity peptides and achieving highly accurate detection and identification of these two cell types using living cells as "fluorescence keys." This system provides a simplified, nontoxic method to replace traditional antibody kits, and strong fluorescence signals can be obtained through various fluorescence detection devices. In addition, the LV-cp biosensors enabled dynamic observation of MSCs differentiation into chondrocytes through changes in the cell fluorescence colors.

Strawberry plant growth enhancement: Effects of artificial light and methyl jasmonate-salicylic acid treatments on physiology and metabolism

Strawberries, known for their antioxidant properties, exhibit changes in physiology and metabolite profiles based on cultivation techniques. In Indonesia, strawberries are typically grown in highland regions, but climate change has necessitated adjustments in cultivation practices to enhance production and quality. This study investigates the adaptation of strawberry plants in lowland environments using light-emitting diodes (LEDs) and the exogenous application of methyl jasmonate (MeJA) and methyl salicylic acid (MeSA). A randomized block design was used with two factors: LED light types and MeJA-MeSA treatments. While the treatments did not significantly affect shoot growth (initially 1.5-2 cm, increasing 3-5 times by day 3), chlorophyll content, or fruit sugar levels, notable effects were observed in leaf glucose accumulation. The control group showed a fivefold increase (0.55 μg ml-1), while LED-hormone treatments resulted in a 27-64 % lower increase (0.20-0.40 μg ml-1). Fructose levels followed a similar pattern, and malic acid content was highest in the MeJA treatment (5.76 mg ml-1), with MeSA treatments also enhancing malic acid (5.91 mg ml-1). The secondary metabolite analysis, conducted using GC-MS and LC-MS, identified key defense-related compounds, including terpenoids, saturated fats, alkaloids, and amino acid derivatives, which play a role in the plant's defense mechanisms. These findings highlight the potential of LED lighting and hormone applications to modulate strawberry physiology and suggest further research into their role in plant stress responses.

Exosomes derived from platelet-rich plasma present a novel potential in repairing knee articular cartilage defect combined with cyclic peptide-modified β-TCP scaffold

BACKGROUND

The aim of this study was to investigate the therapeutic effects and mechanisms of PRP-exos combined with cyclic peptide-modified β-TCP scaffold in the treatment of rabbit knee cartilage defect.

METHODS

PRP-exos were extracted and characterized by TEM, NTA and WB. The therapeutic effects were evaluated by ICRS score, HE staining, Immunohistochemistry, qRT-PCR and ELISA. The repair mechanism of PRP-exos was estimated and predicted by miRNA sequencing analysis and protein-protein interaction network analysis.

RESULTS

The results showed that PRP-exos had a reasonable size distribution and exhibited typical exosome morphology. The combination of PRP-exos and cyclic peptide-modified β-TCP scaffold improved ICRS score and the expression level of COL-2, RUNX2, and SOX9. Moreover, this combination therapy reduced the level of MMP-3, TNF-α, IL-1β, and IL-6, while increasing the level of TIMP-1. In PRP-exos miRNA sequencing analysis, the total number of known miRNAs aligned across all samples was 252, and a total of 91 differentially expressed miRNAs were detected. The results of KEGG enrichment analysis and the protein-protein interaction network analysis indicated that the PI3K/AKT signaling pathway could impact the function of chondrocytes by regulating key transcription factors to repair cartilage defect.

CONCLUSION

PRP-exos combined with cyclic peptide-modified β-TCP scaffold effectively promoted cartilage repair and improved chondrocyte function in rabbit knee cartilage defect. Based on the analysis and prediction of PRP-exos miRNAs sequencing, PI3K/AKT signaling pathway may contribute to the therapeutic effect. These findings provide experimental evidence for the application of PRP-exos in the treatment of cartilage defect.

More than skin deep: cyclic peptides as wound healing and cytoprotective compounds

The prevalence and cost of wounds pose a challenge to patients as well as the healthcare system. Wounds can involve multiple tissue types and, in some cases, become chronic and difficult to treat. Comorbidities may also decrease the rate of tissue regeneration and complicate healing. Currently, treatment relies on optimizing healing factors rather than administering effective targeted therapies. Owing to their enormous diversity in structure and function, peptides are among the most prevalent and biologically important class of compounds and have been investigated for their wound healing bioactivities. A class of these peptides, called cyclic peptides, confer stability and improved pharmacokinetics, and are an ideal source of wound healing therapeutics. This review provides an overview of cyclic peptides that have been shown to promote wound healing in various tissues and in model organisms. In addition, we describe cytoprotective cyclic peptides that mitigate ischemic reperfusion injuries. Advantages and challenges in harnessing the healing potential for cyclic peptides from a clinical perspective are also discussed. Cyclic peptides are a potentially attractive category of wound healing compounds and more research in this field could not only rely on design as mimetics but also encompass de novo approaches as well.

Cyclic Polypeptide D7 Protects Bone Marrow Mesenchymal Cells and Promotes Chondrogenesis during Osteonecrosis of the Femoral Head via Growth Differentiation Factor 15-Mediated Redox Signaling

Osteonecrosis of the femoral head (ONFH) is a debilitating disease that is closely associated with the clinical application of high-dose glucocorticoids. Elevated oxidative stress contributes to the pathophysiological changes observed in ONFH. The lack of effective treatments besides surgical intervention highlights the importance of finding novel therapeutics. Our previous studies demonstrated that D7, a cyclic polypeptide, enhances the adhesion, expansion, and proliferation of bone marrow mesenchymal stem cells (BMSCs). Therefore, in this study, we investigated the therapeutic effects of D7 against ONFH in BMSCs and evaluated the underlying mechanisms. First, we screened for ONFH risk factors. Then, we applied D7 treatment to steroid-induced ONFH (SONFH) in an in vitro model produced by dexamethasone (DEX) to further elucidate the underlying mechanisms. We found negative correlations among oxidative stress marker expression, growth differentiation factor 15 (GDF15) levels, and ONFH. Furthermore, we demonstrated that DEX inhibited the proliferation and induced apoptosis of BMSCs by suppressing GDF15/AKT/mammalian target of rapamycin (mTOR) signaling. D7 alleviated DEX-induced BMSCs injury and restored the chondrogenic function of BMSCs by activating GDF15/AKT/mTOR signaling. In addition, DEX-induced excessive reactive oxygen species (ROS) generation was an upstream trigger of GDF15-mediated signaling, and D7 ameliorated this DEX-induced redox imbalance by restoring the expression of antioxidants, including superoxide dismutase (SOD) 1, SOD2, and catalase, via regulation of GDF15 expression. In conclusion, our findings revealed the potential therapeutic effects of D7 in SONFH and showed that this protective function may be mediated via inhibition of DEX-induced ROS and activation of GDF15/AKT/mTOR signaling, thereby providing insights into the potential applications of D7 in SONFH treatment.

Tissue Engineering Strategies for Treating Avascular Necrosis of the Femoral Head

Avascular necrosis (AVN) of the femoral head commonly leads to symptomatic osteoarthritis of the hip. In older patients, hip replacement is a viable option that restores the hip biomechanics and improves pain but in pediatric, adolescent, and young adult patients hip replacements impose significant activity limitations and the need for multiple revision surgeries with increasing risk of complication. Early detection of AVN requires a high level of suspicion as diagnostic techniques such as X-rays are not sensitive in the early stages of the disease. There are multiple etiologies that can lead to this disease. In the pediatric and adolescent population, trauma is a commonly recognized cause of AVN. The understanding of the pathophysiology of the disease is limited, adding to the challenge of devising a clinically effective treatment strategy. Surgical techniques to prevent progression of the disease and avoid total hip replacement include core decompression, vascular grafts, and use of bone-marrow derived stem cells with or without adjuncts, such as bisphosphonates and bone morphogenetic protein (BMP), all of which are partially effective only in the very early stages of the disease. Further, these strategies often only improve pain and range of motion in the short-term in some patients and do not predictably prevent progression of the disease. Tissue engineering strategies with the combined use of biomaterials, stem cells and growth factors offer a potential strategy to avoid metallic implants and surgery. Structural, bioactive biomaterial platforms could help in stabilizing the femoral head while inducing osteogenic differentiation to regenerate bone and provide angiogenic cues to concomitantly recover vasculature in the femoral head. Moreover, injectable systems that can be delivered using a minimal invasive procedure and provide mechanical support the collapsing femoral head could potentially alleviate the need for surgical interventions in the future. The present review describes the limitations of existing surgical methods and the recent advances in tissue engineering that are leading in the direction of a clinically effective, translational solution for AVN in future.

Phage-Display Based Discovery and Characterization of Peptide Ligands against WDR5

WD40 is a ubiquitous domain presented in at least 361 human proteins and acts as scaffold to form protein complexes. Among them, WDR5 protein is an important mediator in several protein complexes to exert its functions in histone modification and chromatin remodeling. Therefore, it was considered as a promising epigenetic target involving in anti-cancer drug development. In view of the protein-protein interaction nature of WDR5, we initialized a campaign to discover new peptide-mimic inhibitors of WDR5. In current study, we utilized the phage display technique and screened with a disulfide-based cyclic peptide phage library. Five rounds of biopanning were performed and isolated clones were sequenced. By analyzing the sequences, total five peptides were synthesized for binding assay. The four peptides are shown to have the moderate binding affinity. Finally, the detailed binding interactions were revealed by solving a WDR5-peptide cocrystal structure.

B7-H3 in Medulloblastoma-Derived Exosomes; A Novel Tumorigenic Role

(1) Aim: Medulloblastoma is the most common aggressive pediatric cancer of the central nervous system. Improved therapies are necessary to improve life outcomes for medulloblastoma patients. Exosomes are a subset of extracellular vesicles that are excreted outside of the cell, and can transport nucleic acids and proteins from donor cells to nearby recipient cells of the same or dissimilar tissues. Few publications exist exploring the role that exosomes play in medulloblastoma pathogenesis. In this study, we found B7-H3, an immunosuppressive immune checkpoint, present in D283 cell-derived exosomes. (2) Methods: Utilizing mass spectrometry and immunoblotting, the presence of B7-H3 in D283 control and B7-H3 overexpressing exosomes was confirmed. Exosomes were isolated by Systems Biosciences from cultured cells as well as with an isolation kit that included ultracentrifugation steps. Overlay experiments were performed to determine mechanistic impact of exosomes on recipient cells by incubating isolated exosomes in serum-free media with target cells. Impact of D283 exosome incubation on endothelial and UW228 medulloblastoma cells was assessed by immunoblotting. Immunocytochemistry was employed to visualize exosome fusion with recipient cells. (3) Results: Overexpressing B7-H3 in D283 cells increases exosomal production and size distribution. Mass spectrometry revealed a host of novel, pathogenic molecules associated with B7-H3 in these exosomes including STAT3, CCL5, MMP9, and PI3K pathway molecules. Additionally, endothelial and UW228 cells incubated with D283-derived B7-H3-overexpressing exosomes induced B7-H3 expression while pSTAT1 levels decreased in UW228 cells. (4) Conclusions: In total, our results reveal a novel role in exosome production and packaging for B7-H3 that may contribute to medulloblastoma progression.