Biology subjects

Stellpflug, A.

Publications and source records attributed to Stellpflug, A..

4 recordsLinked to original sources

bioRxiv2025

Intracellular Delivery of Bone Nanoparticles to Mitigate Irradiation-Induced Damage in Bone Marrow Mesenchymal Stem Cells

Ionizing radiation (IR)-induced bone damage presents a major clinical challenge by impairing bone marrow function and disrupting normal bone remodeling. Bone regeneration depends on bone marrow-derived mesenchymal stem cells (BMSCs), which are highly sensitive to IR that causes DNA damage, oxidative stress, apoptosis, and a shift from osteogenesis to adipogenesis, ultimately leading to bone loss and impaired healing. This study evaluated the therapeutic potential of intracellularly delivered bone-derived nanoparticles (BPs) in mitigating IR-induced BMSCs damage. We found that IR exposure caused significant BMSCs dysfunction, including reduced proliferation, increased apoptosis, persistent DNA damage, and a shift toward adipogenic differentiation. Treatment with BPs led to efficient intracellular uptake, improved cell morphology, enhanced proliferation, reduced apoptosis, and preservation of balanced differentiation capacity. Transcriptomic analysis via RNA sequencing revealed that BPs restored key molecular pathways disrupted by IR, particularly those involved in cell cycle regulation, extracellular matrix (ECM) remodeling, and apoptosis. By reversing these transcriptional impairments, BPs supported genomic stability and the regenerat ive function of BMSCs. Overall, these findings suggest that BPs effectively counteract IR-induced cellular damage and enhance the regenerative capacity of BMSCs, offering a promising therapeutic strategy for radiation -induced skeletal injuries.

bioengineering↗

bioRxiv2024

Selection of Bone-Targeting Peptides for Therapeutic Intervention: An In Vivo Evaluation and Comparison Study

Hydroxyapatite (HA)-binding peptides are emerging as promising candidates for bone-targeted therapies due to their strong affinity for mineralized tissues and biocompatibility. However, most studies to date have focused on in vitro characterization, providing limited insight into their in vivo performance. This study bridges that gap by evaluating the in vivo behavior of HA-binding peptides D8, E8, YD8, and YE8 using fluorescence imaging to assess their biodistribution in healthy and pathological bone environments. In healthy animal models, D8 demonstrated the strongest binding across mineralized tissues, including the skull, femur, and tibia, while YD8 showed moderate binding. In contrast, E8 and YE8 exhibited limited localization influenced by peptide dosage and binding kinetics. Pathological models, including defective tibia and osteogenesis imperfecta (OIM) mice, revealed preferential accumulation of D8 and YD8 in structurally compromised regions, underscoring their potential for targeting diseased bone microenvironments. Fluorescence imaging, enhanced by spectral unmixing algorithms, proved effective for assessing peptide localization and distribution. These findings highlight the utility of HA-binding peptides for bone-targeted therapies and emphasize the importance of in vivo studies in advancing their therapeutic and diagnostic applications. This work provides a foundation for optimizing peptide designs to improve specificity and efficacy in bone repair and regeneration.

bioengineering↗

bioRxiv2024

Biofabrication of Small Vascular Graft with Acellular Human Amniotic Membrane: A Proof-of-Concept Study in Pig

Synthetic vascular grafts, such as expanded polytetrafluoroethylene (ePTFE), are commonly used for large vessel surgeries [internal diameter (ID) [≥] 10 mm] but present significant challenges in medium to small vessels (ID < 10 mm) due to increased risks of thrombosis, stenosis, and infection. In this study, we developed a small-diameter vascular graft using decellularized human amniotic membrane (DAM graft) (ID = 6 mm) and transplanted it into porcine carotid arteries, comparing it with ePTFE grafts to assess inflammation, biocompatibility, patency, and overall function. One-week post-implantation, ultrasound imaging confirmed blood patency in both graft types. However, after one-month, gross examination revealed pronounced neointimal hyperplasia in ePTFE grafts, while DAM grafts maintained open lumens without signs of stenosis or thrombosis. Histological analysis showed extensive fibrous tissue formation in ePTFE grafts, resulting in luminal narrowing, whereas DAM grafts displayed sustained lumen patency and vascular integration. Immunofluorescence confirmed reduced inflammation and improved tissue organization in DAM grafts, characterized by lower macrophage infiltration and better cellular architecture. These findings suggest that DAM grafts offer superior biocompatibility and significantly lower risks of neointimal hyperplasia, making them a promising alternative for small-diameter vascular surgeries compared to ePTFE grafts.

bioengineering↗

bioRxiv2024

Notch Signaling in regulating Bone-derived Nanoparticles (BNPs) enhanced Osteogenic Differentiation

Mesenchymal stem cells (MSCs)-based bone tissue regeneration has gained significant attention due to their excellent differentiation capacity and immunomodulatory activity. Enhancing osteogenesis regulation is crucial for improving the therapeutic efficacy of MSC- based regeneration. By utilizing the regenerative capacity of bone ECM and the functionality of nanoparticles, we recently engineered bone-based nanoparticles (BNPs) from decellularized porcine bone. The effects of internalization of BNPs on MSCs viability, proliferation, and osteogenic differentiation were first investigated and compared at different time points. The phenotypic behaviors, including cell number, proliferation, and differentiation were characterized and compared. By incorporating this LNA/DNA nanobiosensor and MSCs live cell imaging, we monitored and compared Notch ligand delta-like 4 (Dll4) expression dynamics in cytoplasm and nucleus during osteogenic differentiation. Pharmacological interventions are used to inhibit Notch signaling to examine the mechanisms involved. The results suggest Notch inhibition mediates osteogenic process, with reduced expression of early and late stage of differentiation markers (ALP, calcium mineralization). The internalization of BNPs led to an increase in Dll4 expression, exhibiting a time-dependent pattern that aligned with enhanced cell proliferation and differentiation. Our findings indicate that the observed changes in BNP-treated cells during osteogenic differentiation could be associated with the elevated levels of Dll4 mRNA expression. In summary, this study provides new insights into MSCs osteogenic differentiation and the molecular mechanisms through which BNPs stimulate this process. The results indicate that BNPs influence osteogenesis by modulating Notch ligand Dll4 expression, demonstrating a potential link between Notch signaling and the proteins present in BNPs.

bioengineering↗