Cell-penetrating peptides TAT and 8R functionalize P22 virus-like particles to enhance tissue distribution and retention in vivo.

Virus-like particles (VLPs) are used as nanocontainers for targeted drug, protein, and vaccine delivery. The phage P22 VLP is an ideal macromolecule delivery vehicle, as it has a large exterior surface area, which facilitates multivalent genetic and chemical modifications for cell recognition and penetration. Arginine-rich cell-penetrating peptides (CPPs) can increase cargo transport efficiency in vivo. However, studies on the tissue distribution and retention of P22 VLPs mediated by TAT and 8R are lacking. This study aimed to analyze the TAT and 8R effects on the P22 VLPs transport efficiency and tissue distribution both in vitro and in vivo. We used a prokaryotic system to prepare P22 VLP self-assembled particles and expressed TAT-or 8R-conjugated mCherry on the VLP capsid protein as model cargoes and revealed that the level of P22 VLP-mCherry penetrating the cell membrane was low. However, both TAT and 8R significantly promoted the cellular uptake efficiency of P22 VLPs in vitro, as well as enhanced the tissue accumulation and retention of P22 VLPs in vivo. At 24 h postinjection, TAT enhanced the tissue distribution and retention in the lung, whereas 8R could be better accumulation in brain. Thus, TAT was superior in terms of cellular uptake and tissue accumulation in the P22 VLPs delivery system. Understanding CPP biocompatibility and tissue retention will expand their potential applications in macromolecular cargo delivery.

Identification of a linear B-cell epitope on the "puff" loop of the Senecavirus A VP2 protein involved in receptor binding.

Senecavirus A (SVA) is an important emerging swine pathogen that causes vesicular lesions in swine and acute death in newborn piglets. VP2 plays a significant role in the production of antibodies, which can be used in development of diagnostic tools and vaccines. Herein, the aim of the current study was to identify B-cell epitopes (BCEs) of SVA for generation of epitope-based SVA marker vaccine. Three monoclonal antibodies (mAbs), named 2E4, 1B8, and 2C7, against the SVA VP2 protein were obtained, and two novel linear BCEs, 177SLGTYYR183 and 266SPYFNGL272, were identified by peptide scanning. The epitope 177SLGTYYR183 was recognized by the mAb 1B8 and was fully exposed on the VP2 surface, and alanine scanning analysis revealed that it contained a high continuity of key amino acids. Importantly, we confirmed that 177SLGTYYR183 locates on "the puff" region within the VP2 EF loop, and contains three key amino acid residues involved in receptor binding. Moreover, a single mutation, Y182A, blocked the interaction of the mutant virus with the mAb 1B8, indicating that this mutation is the pivotal point for antibody recognition. In summary, the BCEs that identified in this study could be used to develop diagnostic tools and an epitope-based SVA marker vaccine.

Revolutionizing osteoarthritis treatment: How mesenchymal stem cells hold the key.

Osteoarthritis (OA) is a multifaceted disease characterized by imbalances in extracellular matrix metabolism, chondrocyte and synoviocyte senescence, as well as inflammatory responses mediated by macrophages. Although there have been notable advancements in pharmacological and surgical interventions, achieving complete remission of OA remains a formidable challenge, oftentimes accompanied by significant side effects. Mesenchymal stem cells (MSCs) have emerged as a promising avenue for OA treatment, given their ability to differentiate into chondrocytes and facilitate cartilage repair, thereby mitigating the impact of an inflammatory microenvironment induced by macrophages. This comprehensive review aims to provide a concise overview of the diverse roles played by MSCs in the treatment of OA, while elucidating the underlying mechanisms behind these contributions. Specifically, the roles include: (a) Promotion of chondrocyte and synoviocyte regeneration; (b) Inhibition of extracellular matrix degradation; (c) Attenuating the macrophage-induced inflammatory microenvironment; (d) Alleviation of pain. Understanding the multifaceted roles played by MSCs in OA treatment is paramount for developing novel therapeutic strategies. By harnessing the regenerative potential and immunomodulatory properties of MSCs, it may be possible to devise more effective and safer approaches for managing OA. Further research and clinical studies are warranted to optimize the utilization of MSCs and realize their full potential in the field of OA therapeutics.

Human Adipose-derived Stem Cells Upregulate IGF-1 and Alleviate Osteoarthritis in a Two-stage Rabbit Osteoarthritis Model.

OBJECTIVE: In recent times, it has been recognized that mesenchymal stem cells (MSCs) possess the capability to address osteoarthritis (OA). The objective of this research was to examine the impact of injecting human adipose-derived stem cells (hADSCs) into a novel rabbit osteoarthritis model with dual damage. METHODS: The OA model was established surgically first by medial collateral ligament and anterior cruciate ligament transection and medial meniscectomy, then by articular cartilage full-thickness defect. Enhanced Green Fluorescence Protein expressing lentivirus FG12 was used to label hADSCs, which were then injected into the knee joints. Every single rabbit was sacrificed after 4 and 8 weeks following the surgical procedure. Macroscopic examination, immunohistochemistry staining, magnetic resonance imaging, qRT-PCR, and ELISA analysis were utilized for the assessments. RESULTS: After 4 and 8 weeks, the injection of hADSCs resulted in reduced cartilage loss, minimal fissures and cracks, and a decrease in the volume of joint effusion and cartilage defect as measured by MRI. Moreover, the application of ELISA and qRT-PCR techniques revealed that the administration of hADSCs resulted in an elevation in the IGF-1 concentration. CONCLUSIONS: Based on our findings, it can be inferred that the transplantation of hADSCs facilitates the healing of articular cartilage in the osteoarthritis model of rabbits with double damage. The upregulated IGF-1 may play a crucial part in the process of cartilage repair using hADSCs. The use of hADSC transplantation could potentially be appropriate for clinical implementation in managing osteoarthritis.

Diamond Grinding Wheel Condition Monitoring Based on Acoustic Emission Signals.

Acoustic emission (AE) phenomenon has a direct relationship with the interaction of tool and material which makes AE the most sensitive one among various process variables. However, its prominent sensitivity also means the characteristics of random and board band. Feature representation is a difficult problem for AE-based monitoring and determines the accuracy of monitoring system. It is knottier for the situation of using diamond wheel grinding optical components, not only because of the complexity of grinding process but also the high requirement on surface and subsurface quality. This paper is dedicated to AE-based condition monitoring of diamond wheel during grinding brittle materials and feature representation is paid more attention. AE signal of brittle-regime grinding is modeled as a superposition of a series of burst-type AE events. Theory analysis manifested that original time waveform and frequency spectrum are all suitable for feature representation. Considering the convolution form of b-AE in time domain, a convolutional neural network with original time waveform of AE signals as the input is built for multi-class classification of wheel state. Detailed state division in a wheel's whole life cycle is realized and the accuracy is over 90%. Different from the overlapping in time domain, AE components of different crack mechanisms are probably separated in frequency domain. From this point of view, AE spectrums are more suitable for feature extraction than the original time waveform. In addition, the time sequence of AE samples is essential for the evaluation of wheel's life elapse and making use of sequential information is just the idea behind recurrent neural network (RNN). Therefore, long short-term memory (LSTM), a special kind of RNN, is used to build a regression prediction model of wheel state with AE spectrums as the model input and satisfactory prediction accuracy is acquired on the test set.

Biological characteristic and cytokines response of passages duck plague virus in ducks.

To better understand the pathogenicity of duck plague virus (DPV). The DPV Chinese standard challenge strain (DPV CSC) was continuously passaged 20 times in duck embryo fibroblasts (DEFs). DPV F1 was lethal for 2-week-ducks, but DPV F10 and F20 were not lethal for 2-week ducks, the 528 bp in UL2 region of DPV F1-F20 was deleted, which suggested that the deletion in UL2 region was not related with the virulence of DPV. Compared with DPV F20 infected ducks, IL-8 in DPV F1 infected ducks was significantly upregulated, but IL-1, IL-2,IFNγ and MHC-II were significantly downregulated. ISKNV copies in DPV F10 and F20 infected ducks were lower than the DPV F1 infected ducks. These results showed that massive viruses replication, upregulation of IL-8 expresssion, repression of IL-1, IL-2, IFNγ and MHC-II expression resulted in serious lesions and high mortality. This study provided a in-depth understanding of the immune-related genes expression in the different virulence of DPV.