PDGF-AA guides cell crosstalk between human dental pulp stem cells in vitro via the PDGFR-α/PI3K/Akt axis

AIM

To explore the influence of PDGF-AA on cell communication between human dental pulp stem cells (DPSCs) by characterizing gap junction intercellular communication (GJIC) and its potential biomechanical mechanism.

METHODOLOGY

Quantitative real-time PCR was used to measure connexin family member expression in DPSCs. Cell migration and CCK-8 assays were utilized to examine the influence of PDGF-AA on DPSC migration and proliferation. A scrape loading/dye transfer assay was applied to evaluate GJIC triggered by PDGF-AA, a PI3K/Akt signalling pathway blocker (LY294002) and a PDGFR-α blocker (AG1296). Western blotting and immunofluorescence were used to test the expression and distribution of the Cx43 and p-Akt proteins in DPSCs. Scanning electron microscopy (SEM) and immunofluorescence were used to observe the morphology of GJIC in DPSCs.

RESULTS

PDGF-AA promoted gap junction formation and intercellular communication between human dental pulp stem cells. PDGF-AA upregulates the expression of Cx43 to enhance gap junction formation and intercellular communication. PDGF-AA binds to PDGFR-α and activates PI3K/Akt signalling to regulate cell communication.

CONCLUSIONS

This research demonstrated that PDGF-AA can enhance Cx43-mediated GJIC in DPSCs via the PDGFR-α/PI3K/Akt axis, which provides new cues for dental pulp regeneration from the perspective of intercellular communication.

The Effect of a Rotating Magnetic Field on the Regenerative Potential of Platelets

Platelets are actively involved in tissue injury site regeneration by producing a wide spectrum of platelet-derived growth factors such as PDGF (platelet-derived growth factor), IGF-1 (insulin-like growth factor), TGF-β1 (transforming growth factor β), FGF (fibroblast growth factor), etc. A rotating magnetic field (RMF) can regulate biological functions, including reduction or induction regarding inflammatory processes, cell differentiation, and gene expression, to determine the effect of an RMF on the regenerative potential of platelets. The study group consisted of 30 healthy female and male volunteers (n = 15), from which plasma was collected. A portion of the plasma was extracted and treated as an internal control group. Subsequent doses of plasma were exposed to RMF at different frequencies (25 and 50 Hz) for 1 and 3 h. Then, the concentrations of growth factors (IGF-1, PDGF-BB, TGF-β1, and FGF-1) were determined in the obtained material by the ELISA method. There were statistically significant differences in the PDGF-BB, TGF-β1, IGF-1, and FGF-1 concentrations between the analyzed groups. The highest concentration of PDGF-BB was observed in the samples placed in RMF for 1 h at 25 Hz. For TGF-β1, the highest concentrations were obtained in the samples exposed to RMF for 3 h at 25 Hz and 1 h at 50 Hz. The highest concentrations of IGF-1 and FGF-1 were shown in plasma placed in RMF for 3 h at 25 Hz. An RMF may increase the regenerative potential of platelets. It was noted that female platelets may respond more strongly to RMF than male platelets.

Platelet-derived growth factor-stimulated pulmonary artery smooth muscle cells regulate pulmonary artery endothelial cell dysfunction through extracellular vesicle miR-409-5p

Platelet-derived growth factor (PDGF)-induced changes in vascular smooth muscle cells (VSMCs) stimulate vascular remodeling, resulting in vascular diseases such as pulmonary arterial hypertension. VSMCs communicate with endothelial cells through extracellular vesicles (EVs) carrying cargos, including microRNAs. To understand the molecular mechanisms through which PDGF-stimulated pulmonary artery smooth muscle cells (PASMCs) interact with pulmonary artery endothelial cells (PAECs) under pathological conditions, we investigated the crosstalk between PASMCs and PAECs via extracellular vesicle miR-409-5p under PDGF stimulation. miR-409-5p expression was upregulated in PASMCs upon PDGF signaling, and it was released into EVs. The elevated expression of miR-409-5p was transported to PAECs and led to their impaired function, including reduced NO release, which consequentially resulted in enhanced PASMC proliferation. We propose that the positive regulatory loop of PASMC-extracellular vesicle miR-409-5p-PAEC is a potential mechanism underlying the proliferation of PASMCs under PDGF stimulation. Therefore, miR-409-5p may be a novel therapeutic target for the treatment of vascular diseases, including pulmonary arterial hypertension.

PDGF-AA loaded photo-crosslinked chitosan-based hydrogel for promoting wound healing

Chitosan-based hydrogels are considered to be ideal materials for promoting wound healing due to their nontoxic, biodegradable, and biocompatible properties. However, the weak mechanical strength, hemostatic properties, and adhesive properties of chitosan hydrogels limit their potential applications. In this study, we synthesized methacrylimide-chitosan (MAC)-4-arm polyethylene glycol (PEG)-dopamine (DMA) (MAC-PEG-DMA) hybrid hydrogels containing A-chain homodimers of platelet-derived growth factor (PDGF-AA) through one-pot photo-crosslinking. The resulting hydrogel exhibited improved mechanical strength and hemostatic properties as demonstrated by both in vitro blood clotting assay and rat liver hemorrhage assay. Furthermore, The PDGF-AA loaded hydrogel was also able to accelerate cell migration and proliferation. Data from skin wounds treated with this hybrid hydrogel showed faster wound closure and collagen maturation. Therefore, MAC-PEG-DMA (PDGF-AA) has great potential as a dressing to promote wound healing.

Recent Achievements in the Development of Biomaterials Improved with Platelet Concentrates for Soft and Hard Tissue Engineering Applications

Platelet concentrates such as platelet-rich plasma, platelet-rich fibrin or concentrated growth factors are cost-effective autologous preparations containing various growth factors, including platelet-derived growth factor, transforming growth factor β, insulin-like growth factor 1 and vascular endothelial growth factor. For this reason, they are often used in regenerative medicine to treat wounds, nerve damage as well as cartilage and bone defects. Unfortunately, after administration, these preparations release growth factors very quickly, which lose their activity rapidly. As a consequence, this results in the need to repeat the therapy, which is associated with additional pain and discomfort for the patient. Recent research shows that combining platelet concentrates with biomaterials overcomes this problem because growth factors are released in a more sustainable manner. Moreover, this concept fits into the latest trends in tissue engineering, which include biomaterials, bioactive factors and cells. Therefore, this review presents the latest literature reports on the properties of biomaterials enriched with platelet concentrates for applications in skin, nerve, cartilage and bone tissue engineering.

Serum levels of PDGF-CC as a potential biomarker for the diagnosis of Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute systemic vasculitis of unknown etiology that predominantly affects children, and no specific diagnostic biomarkers for KD are available. Platelet-derived growth factor CC (PDGF-CC) is a peptide with angiogenic properties that has been amply demonstrated to play a critical role in the cardiovascular system. This study aimed to investigate the serum expression of PDGF-CC in children with KD and to evaluate the ability of PDGF-CC to diagnose KD.

METHODS

A total of 96 subjects, including 59 KD patients, 17 febrile controls (FC), and 20 healthy controls (HC), were enrolled. Serum levels of PDGF-CC were measured via enzyme-linked immunosorbent assay. The associations between PDGF-CC and clinical laboratory parameters were investigated by correlation analysis. The diagnostic performance was assessed by receiver operating characteristic (ROC) curve analysis.

RESULTS

Serum PDGF-CC levels in the KD group were significantly higher than in the FC and HC groups. Serum PDGF-CC levels in the KD group were positively correlated with white blood cell counts, percentage of neutrophils, IL-2, IL-12p70, TNF-α, and IL-1β levels, and negatively correlated with the percentage of lymphocytes. In the analysis of ROC curves, the area under the curve was 0.796 (95% confidence interval 0.688-0.880; P < 0.0001) for PDGF-CC and increased to 0.900 (95% confidence interval 0.808-0.957; P < 0.0001) in combination with white blood cell counts and C-reactive protein.

CONCLUSIONS

PDGF-CC is a potential biomarker for KD diagnosis, and the combination with white blood cell counts and C-reactive protein can further improve diagnostic performance.

A Systematic Review of the Metabolism of High-Grade Gliomas: Current Targeted Therapies and Future Perspectives

High-grade glial tumors (HGGs) exhibit aggressive growth patterns and high recurrence rates. The prevailing treatment approach comprises radiation therapy (RT), chemotherapy (CMT), and surgical resection. Despite the progress made in traditional treatments, the outlook for patients with HGGs remains bleak. Tumor metabolism is emerging as a potential target for glioma therapies, a promising approach that harnesses the metabolism to target tumor cells. However, the efficacy of therapies targeting the metabolism of HGGs remains unclear, compelling a comprehensive review. This study aimed to assess the outcome of present trials on HGG therapies targeting metabolism. A comprehensive search of PubMed, Ovid MEDLINE, and Ovid EMBASE was conducted until November 2023. The search method used pertinent Medical Subject Heading (MeSH) terminologies and keywords referring to "high-grade gliomas", "metabolism", "target therapies", "monoclonal antibodies", "overall survival", and "progression-free survival". The review analyzed studies that focused on therapies targeting the metabolism of HGGs in human subjects. These studies included both randomized controlled trials (RCTs) and non-randomized controlled trials (NRCTs). Out of 284 articles identified, 23 trials met the inclusion criteria and were thoroughly analyzed. Phase II trials were the most numerous (62%). Targeted metabolic therapies were predominantly used for recurrent HGGs (67%). The most common targeted pathways were the vascular endothelial growth factor (VEGF, 43%), the human epidermal growth factor receptor (HER, 22%), the platelet-derived growth factor (PDGF, 17%), and the mammalian target of rapamycin (mTOR, 17%). In 39% of studies, the subject treatment was combined with CMT (22%), RT (4%), or both (13%). The median OS widely ranged from 4 to 26.3 months, while the median PFS ranged from 1.5 to 13 months. This systematic literature review offers a thorough exploration of the present state of metabolic therapies for HGGs. The multitude of targeted pathways underscores the intricate nature of addressing the metabolic aspects of these tumors. Despite existing challenges, these findings provide valuable insights, guiding future research endeavors. The results serve as a foundation for refining treatment strategies and enhancing patient outcomes within the complex landscape of HGGs.

Biological and Cellular Properties of Advanced Platelet-Rich Fibrin (A-PRF) Compared to Other Platelet Concentrates: Systematic Review and Meta-Analysis

Platelet concentrates are used for cell induction and stimulation in tissue repair processes. The aim of the present systematic review and meta-analysis was to compare the biological and cellular properties of advanced platelet-rich fibrin (A-PRF) to those of other platelet concentrates. Searches were conducted on the PubMed/Medline, Scopus, Web of Science, Embase and LILACS databases using a search strategy oriented by the guiding question. A total of 589 records were retrieved. Seven articles of in vitro experimental studies were selected for qualitative data analysis and four were selected for meta-analysis. The release of growth factors, distribution of cells in the fibrin membrane, and cell viability, the fibrin network, and fibroblast migration were investigated. In the final analysis, statistically significant differences were found for the A-PRF group with regard to platelet-derived growth factor, transforming growth factor, epidermal growth factor and vascular endothelial growth factor at all assessment times. A difference was found with regard to bone morphogenetic protein only in the later assessment, and no differences among groups were found with regard to platelet-derived growth factor or insulin-like growth factor. The results of this systematic review and meta-analysis suggest that A-PRF has superior cellular properties and better release of growth factors compared to other platelet concentrates.

Identification of cytokine-induced cell communications by pan-cancer meta-analysis

Cancer immune responses are complex cellular processes in which cytokine-receptor interactions play central roles in cancer development and response to therapy; dysregulated cytokine-receptor communication may lead to pathological processes, including cancer, autoimmune diseases, and cytokine storm; however, our knowledge regarding cytokine-mediated cell-cell communication (CCI) in different cancers remains limited. The present study presents a single-cell and pan-cancer-level transcriptomics integration of 41,900 cells across 25 cancer types. We developed a single-cell method to actively express 62 cytokine-receptor pairs to reveal stable cytokine-mediated cell communications involving 84 cytokines and receptors. The correlation between the sample-based CCI profile and the interactome analysis indicates multiple cytokine-receptor modules including TGFB1, IL16ST, IL15, and the PDGF family. Some isolated cytokine interactions, such as FN1-IL17RC, displayed diverse functions within over ten single-cell transcriptomics datasets. Further functional enrichment analysis revealed that the constructed cytokine-receptor interaction map is associated with the positive regulation of multiple immune response pathways. Using public TCGA pan-cancer mutational data, co-mutational analysis of the cytokines and receptors provided significant co-occurrence features, implying the existence of cooperative mechanisms. Analysis of 10,967 samples from 32 TCGA cancer types revealed that the 84 cytokine and receptor genes are significantly associated with clinical survival time. Interestingly, the tumor samples with mutations in any of the 84 cytokines and receptors have a substantially higher mutational burden, offering insights into antitumor immune regulation and response. Clinical cancer stage information revealed that tumor samples with mutations in any of the 84 cytokines and receptors stratify into earlier tumor stages, with unique cellular compositions and clinical outcomes. This study provides a comprehensive cytokine-receptor atlas of the cellular architecture in multiple cancers at the single-cell level.

Sclerotome-derived PDGF signaling functions as a niche cue responsible for primitive erythropoiesis

Primitive erythropoiesis serves a vital role in embryonic development, generating primitive red blood cells responsible for transportation of oxygen throughout the body. Although diverse niche factors are known to function in definitive hematopoiesis, the microenvironment contributing to primitive hematopoiesis remains largely elusive. Here, we report that platelet-derived growth factor (PDGF) signaling is required for erythroid progenitor differentiation in zebrafish. Ablating pdgfαa (also known as pdgfaa) and pdgfαb (also known as pdgfab) or blocking PDGF signaling with an inhibitor impairs erythroid progenitor differentiation, thus resulting in a significant decrease in the number of erythrocytes. We reveal that pdgfαb is expressed in sclerotomal cells, and that its receptor genes, pdgfra and pdgfrb, are expressed in the adjacent erythroid progenitor cells. Sclerotome-specific overexpression of pdgfαb effectively restores primitive erythropoiesis in pdgfαa-/-;pdgfαb-/- mutant embryos. In addition, we have defined ERK1/2 signaling as a downstream pathway of PDGF signaling during embryonic erythropoiesis. Taken together, our findings indicate that PDGF signaling derived from sclerotome functions as a niche cue for primitive erythropoiesis.

Roles of DSCC1 and GINS1 in gastric cancer

Gastric carcinoma is a common malignant tumor originating from gastric mucosal epithelium. However, role of DS-cell cycle-dependent protein 1 (DSCC1) and GINS1 in gastric carcinoma remains unclear. The gastric carcinoma datasets GSE79973 and GSE118916 were downloaded from gene expression omnibus. Multiple datasets were merged and batched. Differentially expressed genes (DEGs) were screened and weighted gene co-expression network analysis was performed. Functional enrichment analysis, gene set enrichment analysis and immune infiltration analysis were performed. Construction and analysis of protein-protein interaction Network. Survival analysis and comparative toxicogenomics database were performed. A heat map of gene expression was drawn. Target Scan screen miRNAs regulating DEGs. Two thousand forty-four DEGs were identified. According to gene ontology analysis, in biological process, they were mainly enriched in cell migration, transforming growth factor β receptor signaling pathway, angiogenesis, and steroid metabolism process. In cellular component, they were mainly enriched in extracellular vesicles, basement membrane, endoplasmic reticulum lumen, and extracellular space. In molecular function, they focused on extracellular matrix structural components, protein binding, platelet-derived growth factor binding, and catalytic activity. In Kyoto encyclopedia of genes and genomes, they were mainly enriched in protein digestion and absorption, metabolic pathways, fatty acid degradation, Glycerophospholipid metabolism, ether lipid metabolism. Gene set enrichment analysis showed that DEGs were mainly enriched in transforming growth factor β receptor signaling pathway, steroid metabolism process, basement membrane, endoplasmic reticulum lumen, structural components of extracellular matrix, platelet-derived growth factor binding, Glycerophospholipid metabolism, ether lipid metabolism. The results of immune infiltration analysis showed that expression of T cell CD4 memory resting was lower in the samples of gastric cancer. The core genes (TRIP13, CHEK1, DSCC1, GINS1) are protective factors, their expression shows a downward trend with increase of risk score. Comparative toxicogenomics database analysis showed that TRIP13, CHEK1, DSCC1, GINS1 were related to gastric tumors, gastric diseases, tumors, inflammation, and necrosis. DSCC1 and GINS1 are highly expressed in gastric cancer. Higher expression levels of DSCC1 and GINS1, worse the prognosis.

Computational evidence for multi-layer crosstalk between the cadherin-11 and PDGFR pathways

Various cell surface receptors play an important role in the differentiation and self-renewal of human mesenchymal stem cells (hMSCs). One example of such receptors are the cadherins, which maintain cell-cell adhesion and mechanically couple cells together. Recently, cadherin-11, which is a member of the type II classical cadherin family, has been shown to be involved in the fate commitment of hMSCs. Interestingly, cadherin-11 has no known intrinsic signaling activity and is thought to affect cell behavior via interactions with other cell surface receptors. Members of the platelet-derived growth factor receptor (PDGFR) family are hypothesized to be one of the interaction partners of cadherin-11. Experiments confirmed that PDGFR-α binding to extracellular cadherin-11 regions increases the PDGFR-α activity, whereas the interaction between PDGFR-β and cadherin-11 suppresses the activity of the growth factor receptor. Cadherin-11 knockdown experiments also decreased cell proliferation. These interactions between cadherin-11 and PDGFRs indicate a crosstalk between these receptors and their downstream signaling activities but the nature of this crosstalk is not entirely known. In this study, we used a computational model to represent the experimentally proven interactions between cadherin-11 and the two PDGFRs and we inspected whether the crosstalk also exists downstream of the signaling initiated by the two receptor families. The computational framework allowed us to monitor the relative activity levels of each protein in the network. We performed model simulations to mimic the conditions of previous cadherin-11 knockdown experiments and to predict the effect of crosstalk on cell proliferation. Overall, our predictions suggest the existence of another layer of crosstalk, namely between β-catenin (downstream to cadherin-11) and an ERK inhibitor protein (e.g. DUSP1), different than the crosstalk at the receptor level between cadherin-11 and PDGFR-α and -β. By investigating the multi-level crosstalk between cadherin and PDGFRs computationally, this study contributes to an improved understanding of the effect of cell surface receptors on hMSCs proliferation.

Optimal controlling of anti-TGF-[Formula: see text] and anti-PDGF medicines for preventing pulmonary fibrosis

In the repair of injury, some transforming growth factor-[Formula: see text]s (TGF-[Formula: see text]s) and platelet-derived growth factors (PDGFs) bind to fibroblast receptors as ligands and cause the differentiation of fibroblasts into myofibroblasts. When the injury repair is repeated, the myofibroblasts proliferate excessively, forming fibrotic tissue. We goal to control myofibroblasts proliferation and apoptosis with anti-transforming growth factor-[Formula: see text] (anti-TGF-[Formula: see text]) and anti-platelet-derived growth factor (anti-PDGF) medicines. The novel optimal regulator control problem with two controls (medicines) is proposed to simulate how to the preventing pulmonary fibrosis. Idiopathic pulmonary fibrosis (IPF) consists of restoring a system of cells, protein, and tissue networks with injury and scar. Myofibroblasts proliferation back to its equilibrium position after it has been disturbed by abnormal repair. Thus, the optimal regulator control problem with a parabolic partial differential equation as a constraint, zero flux boundary, and given specific initial conditions, is considered. The myofibroblast diffusion equation stands as a governing dynamic system while the objective function is the summation of myofibroblast, anti-TGF-[Formula: see text] and anti-PDGF medicines for the fixed final time. Here, myofibroblast is a nonlinear state of time while anti-TGF-[Formula: see text] and anti-PDGF are two unknown control functions. In order to solve the corresponding problem a weighted Galerkin method is used. Firstly, we convert the myofibroblast diffusion equation to a system of ordinary differential equations using the Lagrangian interpolation polynomials defined at Gauss-Lobatto integration points. Secondly, by the calculus of variations, the optimal control problem is solved successfully using canonical Hamiltonian and extended Riccati equations. Numerical results are given, and the plots are depicted. Moreover, solutions to the problem in which there is no control are compared. Numerical results show that, over time, the myofibroblast increases and then remains constant when there is no control. In contrast, the current solution decreases and vanishes after 300 days by prescribing controller medicines for anti-TGF-[Formula: see text] and anti-PDGF. The optimal strategy proposed in this paper helps practitioners to reduce myofibroblasts by controlling both anti-TGF-[Formula: see text] and anti-PDGF medicines.

Regulation of Smooth Muscle Cell Proliferation by Mitochondrial Ca2+ in Type 2 Diabetes

Type 2 diabetes (T2D) is associated with increased risk of atherosclerotic vascular disease due to excessive vascular smooth muscle cell (VSMC) proliferation. Here, we investigated the role of mitochondrial dysfunction and Ca2+ levels in VSMC proliferation in T2D. VSMCs were isolated from normoglycemic and T2D-like mice induced by diet. The effects of mitochondrial Ca2+ uptake were studied using mice with selectively inhibited mitochondrial Ca2+/calmodulin-dependent kinase II (mtCaMKII) in VSMCs. Mitochondrial transition pore (mPTP) was blocked using ER-000444793. VSMCs from T2D compared to normoglycemic mice exhibited increased proliferation and baseline cytosolic Ca2+ levels ([Ca2+]cyto). T2D cells displayed lower endoplasmic reticulum Ca2+ levels, reduced mitochondrial Ca2+ entry, and increased Ca2+ leakage through the mPTP. Mitochondrial and cytosolic Ca2+ transients were diminished in T2D cells upon platelet-derived growth factor (PDGF) administration. Inhibiting mitochondrial Ca2+ uptake or the mPTP reduced VSMC proliferation in T2D, but had contrasting effects on [Ca2+]cyto. In T2D VSMCs, enhanced activation of Erk1/2 and its upstream regulators was observed, driven by elevated [Ca2+]cyto. Inhibiting mtCaMKII worsened the Ca2+ imbalance by blocking mitochondrial Ca2+ entry, leading to further increases in [Ca2+]cyto and Erk1/2 hyperactivation. Under these conditions, PDGF had no effect on VSMC proliferation. Inhibiting Ca2+-dependent signaling in the cytosol reduced excessive Erk1/2 activation and VSMC proliferation. Our findings suggest that altered Ca2+ handling drives enhanced VSMC proliferation in T2D, with mitochondrial dysfunction contributing to this process.

The effects of mechanical instability on PDGF mediated inflammatory response at early stage of fracture healing under diabetic condition

BACKGROUND AND OBJECTIVE

Mechanical stability plays an important role in fracture healing process. Excessive interfragmentary movement will continuously damage the tissue and newly formed capillaries at the fracture site, which leads to overproduction of platelet-derived growth factor (PDGF) that attracts more macrophages into fracture callus, ultimately persistent and enhanced inflammatory response happens. For diabetic condition, the impact of mechanical instability of fracture site on inflammatory response could be further compliciated and the relevant research in this field is relatively limited.

METHODS

Building on previous experimental studies, this study presents a numerical model consisting of a system of reactive-transport equations representing the transport as well as interactions of different cells and cytokines within the fracture callus. The model is initially validated by available experimental data, and then implemented to investigate the role of mechanical stability of fracture site in inflammatory response during early stage of healing. It is assumed that there is an increased release of PDGF due to the rupture of blood vessels resulting from mechanical instability, which leads to increased production of inflammatory cytokines (i.e., TNF-α). The bone healing process under three different conditions were investigated, i.e., mechanically stable condition with normal inflammatory response (Control, Case 1), mechanically unstable condition with normal inflammatory response (Case 2) and mechanically unstable condition with diabetes (Case 3).

RESULTS

Mechanical instability can promote the macrophage infiltration and thus induce an enhanced and prolonged inflammatory response, which could impede the MSCs proliferation during the early fracture healing stage (e.g., compared with the control condition, the MSCs concentration in unstable fracture with normal inflammatory response can be reduced by 3.2% and 5.2% on day 2 and day 10 post-fracture, respectively). Under diabetic condition, the mechanical instability of fracture site could lead to a significant increase of TNF-α concentration in fracture callus (Case 3) in comparison to control (Case 1) (e.g., three-fold increase in TNF-α concentration compared to control). In addition, the results show that the mechanical instability affects the cell differentiation and proliferation in fracture callus in a spatially dependent manner, e.g., for diabetic fracture patients, the mechanical instability could potentially decrease the concentration of MSCs, osteoblasts and chondrocytes by around 39%, 30% and 29% in cortical callus, respectively, in comparison to control.

CONCLUSION

The mechanical instability together with diabetic condition can significantly affect the natural resolution of inflammation during early stage of healing by turning acute inflammation into chronic inflammation which is characterized by a continuously upregulated TNF-α pathway.

Plasma Cytokine Profiles in Patients With Polypoidal Choroidal Vasculopathy and Neovascular Age-Related Macular Degeneration

PURPOSE

The concentrations of cytokines in plasma may be different between neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV). We studied plasma levels of cytokines in patients with nAMD and PCV and compared them with control individuals.

METHODS

This was a prospective, clinic-based, case-control study of treatment-naive participants (n=49) with PCV (n=24), nAMD (n=11), and cataract controls (n=14). We sampled fresh venous blood and isolated plasma for analysis. Plasma concentrations of 34 angiogenic and inflammatory cytokines were determined by Luminex bead-based multiplex array.

RESULTS

After adjusting for gender and age using multivariate logistic analysis, we found that the plasma concentrations of monocyte chemoattractant protein-1, vascular endothelial growth factor (VEGF)-A, and VEGF-D significantly higher in both nAMD and PCV patients than those in controls (all P<0.05, times in nAMD: 3.5, 4.3, and 13.8, respectively, times in PCV: 4.1, 4.0, and 11.5, respectively). In contrast, the plasma concentration of platelet-derived growth factor-BB was significantly lower in nAMD and PCV patients than those in controls (all P<0.05, times in nAMD: 1.6, times in PCV: 1.7). The plasma levels of leukemia inhibitory factor in nAMD group were significantly higher compared with PCV group (P<0.0167).

CONCLUSIONS

Multiple cytokines involved in systemic inflammation and angiogenesis including monocyte chemoattractant protein-1, platelet-derived growth factor-BB, VEGF-A, and VEGF-D may contribute to the pathogenesis of nAMD and PCV. Measurement of leukemia inhibitory factor in the plasma may help differentiate nAMD from PCV. This finding suggests that the 2 disorders may have different molecular mechanisms, and additional longitudinal studies will be needed to determine whether these findings have clinical relevance to influence treatment algorithms or provide novel targets for medical therapy.

Effects of salvianolic acid A and salvianolic acid B in renal interstitial fibrosis via PDGF-C/PDGFR-α signaling pathway

BACKGROUND

Renal interstitial fibrosis (RIF) is the main pathological feature of end-stage renal disease (ESRD) caused by various chronic kidney diseases (CKD), and is closely related to renal dysfunction and patient prognosis. Salvianolic acid A (Sal A) and salvianolic acid B (Sal B), isolated from traditional Chinese medicine Salviae miltiorrhizae, have been confirmed to have anti-fibrotic effects on liver, cardiac and kidney. However, the precise molecular mechanism underlying the nephroprotective effects of Sal A and Sal B, and whether there is a difference between the two in RIF are still unclear.

PURPOSE

This study investigated the pharmacological effects of Sal A and Sal B in RIF and explore the underlying mechanisms by in vivo and in vitro experiments.

METHODS

The nephroprotective effects of Sal A, Sal B and Sal A+B were evaluated by assessing the parameters related to kidney function such as renal histology, renal function, urinary protein NAG, urinary β2 microglobulin. In addition, RIF-related markers such as CTCF and Par3 were also detected. Thereafter, the related protein or gene levels of PDGF-C/PDGFR-α signaling pathways, apoptosis and endoplasmic reticulum stress (ERS) were determined by western blot, real-time PCR, flow cytometry or immunofluorescence staining.

RESULTS

In vivo, the results showed that Sal A, Sal B and Sal A+B partially improved kidney dysfunction, increased the expression of Par-3 and reduced the expression of CTGF, PDGF-C and PDGFR-α. In vitro, the results also showed that Sal A, Sal B and Sal A+B reversed apoptosis and ERS in HSA-induced HK-2 cells via regulating PDGF-C/PDGFR-α signaling pathway.

CONCLUSION

This article revealed a novel mechanism linking PDGF-C/PDGFR-α signaling pathway to RIF and suggested that Sal A, Sal B and Sal A+B were considered as potential therapeutic agents for the amelioration of RIF.

The Production of Recombinant PDGF D Using the Second Generation Modified Vaccinia Ankara (MVA) Viral System

The vaccinia virus expression system is known for the efficient production of recombinant proteins with “appropriate” posttranslational modification using desired mammalian cell lines. However, being a replication competent virus, vaccinia virus poses a health threat to immunocompromised individuals and requires biosafety level 2 (BSL2) laboratory precautions, thereby restricting its use by the scientific community. Development of the host range restricted modified vaccinia Ankara (MVA) system has allowed researchers to work with a safer virus even at BSL1. Here, we report on the use of an improved second generation MVA viral system incorporating two selective markers and fluorescent proteins for easier recombinant virus identification. Notably, we demonstrate that this novel system is capable of producing secreted recombinant proteins, a finding not previously reported. Through purification and characterization of wild type and mutant platelet‐derived growth factor D (PDGF D) dimer species, we demonstrate this system is capable of producing the latent full‐length PDGF D dimer, partially processed intermediate dimer (hemidimer), as well as fully processed growth factor domain dimer that show chemical integrity and biological activity. Importantly, this system is amenable to scaling up for the mass production of recombinant PDGF D (rPDGF D) dimer species.

Associations of urinary polycyclic aromatic hydrocarbon metabolites and blood pressure with the mediating role of cytokines: A panel study among children

Little was known regarding the relations of polycyclic aromatic hydrocarbon (PAH) mixture with children's blood pressure (BP) and its potential mechanism. We conducted a panel study with up to 3 visits across 3 seasons in 2017-2018 among 103 children aged 4-13 years. Urinary PAH metabolites (OH-PAHs) were measured by gas chromatograph-tandem triple quadrupole mass spectrometer, and serum cytokines were detected by Bio-Rad 48-Plex Screening Panel. We employed linear mixed-effects models to assess the relations of each urinary OH-PAH with BP, least absolute shrinkage and selection operator (LASSO), and weighted quantile sum (WQS) regression to evaluate associations of OH-PAHs mixture with BP, and mediation analyses for the role of serum cytokines. We found the consistently positive associations of 1-hydroxynaphthalene and 9-hydroxyphenanthrene (9-OHPh) with systolic BP (SBP), 4-OHPh, and 9-OHPh with diastolic BP (DBP) and mean arterial pressure (MAP) in a dose-responsive manner. For instance, each 1-fold increment of 9-OHPh was related with increase of 0.92% (95% confidence interval (CI): 0.25%, 1.60%) in SBP, 1.32% (95%CI: 0.25%, 2.39%) in DBP, and 1.15% (95%CI: 0.40%, 1.88%) in MAP. Meanwhile, based on LASSO and WQS regression, OH-PAHs mixture was linked with increased DBP and MAP, to which 9-OHPh and 4-OHPh were the major contributors. Such relationships were modified by passive smoking status and 3-4 times stronger in passive smokers than non-passive smokers. A 1-fold increase in 9-OHPh was associated with an elevation of 3.51% in SBP among passive smokers while that of 0.55% in SBP among non-passive smokers. Furthermore, 4-OHPh and 9-OHPh were related to multiple cytokines elevation, of which platelet-derived growth factor (PDGF) mediated 9.99% and 12.57% in 4-OHPh-related DBP and MAP elevation, respectively. Accordingly, urinary OH-PAHs dominated by 9-OHPh and 4-OHPh were dose-responsively associated with elevated BP whereby a mechanism partly involving PDGF among children.

Regnase-1 Prevents Pulmonary Arterial Hypertension Through mRNA Degradation of Interleukin-6 and Platelet-Derived Growth Factor in Alveolar Macrophages

BACKGROUND

Pulmonary arterial hypertension (PAH) is a type of pulmonary hypertension (PH) characterized by obliterative pulmonary vascular remodeling, resulting in right-sided heart failure. Although the pathogenesis of PAH is not fully understood, inflammatory responses and cytokines have been shown to be associated with PAH, in particular, with connective tissue disease-PAH. In this sense, Regnase-1, an RNase that regulates mRNAs encoding genes related to immune reactions, was investigated in relation to the pathogenesis of PH.

METHODS

We first examined the expression levels of ZC3H12A (encoding Regnase-1) in peripheral blood mononuclear cells from patients with PH classified under various types of PH, searching for an association between the ZC3H12A expression and clinical features. We then generated mice lacking Regnase-1 in myeloid cells, including alveolar macrophages, and examined right ventricular systolic pressures and histological changes in the lung. We further performed a comprehensive analysis of the transcriptome of alveolar macrophages and pulmonary arteries to identify genes regulated by Regnase-1 in alveolar macrophages.

RESULTS

ZC3H12A expression in peripheral blood mononuclear cells was inversely correlated with the prognosis and severity of disease in patients with PH, in particular, in connective tissue disease-PAH. The critical role of Regnase-1 in controlling PAH was also reinforced by the analysis of mice lacking Regnase-1 in alveolar macrophages. These mice spontaneously developed severe PAH, characterized by the elevated right ventricular systolic pressures and irreversible pulmonary vascular remodeling, which recapitulated the pathology of patients with PAH. Transcriptomic analysis of alveolar macrophages and pulmonary arteries of these PAH mice revealed that Il6, Il1b, and Pdgfa/b are potential targets of Regnase-1 in alveolar macrophages in the regulation of PAH. The inhibition of IL-6 (interleukin-6) by an anti-IL-6 receptor antibody or platelet-derived growth factor by imatinib but not IL-1β (interleukin-1β) by anakinra, ameliorated the pathogenesis of PAH.

CONCLUSIONS

Regnase-1 maintains lung innate immune homeostasis through the control of IL-6 and platelet-derived growth factor in alveolar macrophages, thereby suppressing the development of PAH in mice. Furthermore, the decreased expression of Regnase-1 in various types of PH implies its involvement in PH pathogenesis and may serve as a disease biomarker, and a therapeutic target for PH as well.

PDGF/PDGFR: A Possible Molecular Target in Scleroderma Fibrosis

Systemic sclerosis (SSc) is a clinically heterogeneous disorder of the connective tissue characterized by vascular alterations, immune/inflammatory manifestations, and organ fibrosis. SSc pathogenesis is complex and still poorly understood. Therefore, effective therapies are lacking and remain nonspecific and limited to disease symptoms. In the last few years, many molecular and cellular mediators of SSc fibrosis have been described, providing new potential options for targeted therapies. In this review: (i) we focused on the PDGF/PDGFR pathway as key signaling molecules in the development of tissue fibrosis; (ii) we highlighted the possible role of stimulatory anti-PDGFRα autoantibodies in the pathogenesis of SSc; (iii) we reported the most promising PDGF/PDGFR targeting therapies.

Growth Factor Roles in Soft Tissue Physiology and Pathophysiology

Repair and healing of injured and diseased tendons has been traditionally fraught with apprehension and difficulties, and often led to rather unsatisfactory results. The burgeoning research field of growth factors has opened new venues for treatment of tendon disorders and injuries, and possibly for treatment of disorders of the aorta and major arteries as well. Several chapters in this volume elucidate the role of transforming growth factor β (TGFß) in pathogenesis of several heritable disorders affecting soft tissues, such as aorta, cardiac valves, and tendons and ligaments. Several members of the bone morphogenetic group either have been approved by the FDA for treatment of non-healing fractures or have been undergoing intensive clinical and experimental testing for use of healing bone fractures and tendon injuries. Because fibroblast growth factors (FGFs) are involved in embryonic development of tendons and muscles among other tissues and organs, the hope is that applied research on FGF biological effects will lead to the development of some new treatment strategies providing that we can control angiogenicity of these growth factors. The problem, or rather question, regarding practical use of imsulin-like growth factor I (IGF-I) in tendon repair is whether IGF-I acts independently or under the guidance of growth hormone. FGF2 or platelet-derived growth factor (PDGF) alone or in combination with IGF-I stimulates regeneration of periodontal ligament: a matter of importance in Marfan patients with periodontitis. In contrast, vascular endothelial growth factor (VEGF) appears to have rather deleterious effects on experimental tendon healing, perhaps because of its angiogenic activity and stimulation of matrix metalloproteinases-proteases whose increased expression has been documented in a variety of ruptured tendons. Other modalities, such as local administration of platelet-rich plasma (PRP) and/or of mesenchymal stem cells have been explored extensively in tendon healing. Though treatment with PRP and mesenchymal stem cells has met with some success in horses (who experience a lot of tendon injuries and other tendon problems), the use of PRP and mesenchymal stem cells in people has been more problematic and requires more studies before PRP and mesenchymal stem cells can become reliable tools in management of soft tissue injuries and disorders.

High expression of PDGFA predicts poor prognosis of esophageal squamous cell carcinoma

Platelet-derived growth factor A (PDGFA), the most known member of PDGF family, plays a crucial role in occurrence and progression of different tumors. However, PDGFA expression and its clinical significance in esophageal squamous cell carcinoma (ESCC) are not clear. The present study aimed to assess the expression and prognostic value of PDGFA in ESCC.The Gene Expression Omnibus databases (GSE53625, GSE23400, and GSE67269) and fresh clinical samples were employed for detecting PDGFA messenger RNA expression in ESCC. The associations of PDGFA expression with clinicopathological characteristics were evaluated by chi-square test. Kaplan-Meier analysis and Cox proportional hazard regression model were performed to determine the prognostic value of PDGFA in ESCC patients. PDGFA-related signaling pathways were defined by gene set enrichment analysis based on Gene Expression Omnibus databases.The PDGFA messenger RNA expression was upregulated in ESCC tissues compared with paired adjacent noncancerous tissues (P < .05) and was positively correlated with T stage (P < .05). Kaplan-Meier survival analysis suggested that ESCC patients with high PDGFA expression were associated with poorer overall survival compared to those with low PDGFA expression (P < .05), especially in advanced T stage (P < .05). Cox analyses showed that high expression of PDGFA was an independent predictor for poor prognosis in ESCC patients. Gene set enrichment analysis identified 3 signaling pathways (extracellular matrix receptor interaction, focal adhesion, and glycosaminoglycan biosynthesis chondroitin sulfate) that were enriched in PDGFA high expression phenotype (all P < .01).PDGFA may serve as an oncogene in ESCC and represent an independent molecular biomarker for prognosis of ESCC patients.

Induction of muscle-regenerative multipotent stem cells from human adipocytes by PDGF-AB and 5-azacytidine

Terminally differentiated murine osteocytes and adipocytes can be reprogrammed using platelet-derived growth factor-AB and 5-azacytidine into multipotent stem cells with stromal cell characteristics. We have now optimized culture conditions to reprogram human adipocytes into induced multipotent stem (iMS) cells and characterized their molecular and functional properties. Although the basal transcriptomes of adipocyte-derived iMS cells and adipose tissue-derived mesenchymal stem cells were similar, there were changes in histone modifications and CpG methylation at cis-regulatory regions consistent with an epigenetic landscape that was primed for tissue development and differentiation. In a non-specific tissue injury xenograft model, iMS cells contributed directly to muscle, bone, cartilage, and blood vessels, with no evidence of teratogenic potential. In a cardiotoxin muscle injury model, iMS cells contributed specifically to satellite cells and myofibers without ectopic tissue formation. Together, human adipocyte-derived iMS cells regenerate tissues in a context-dependent manner without ectopic or neoplastic growth.

Dynamic Expression of Platelet-Derived Growth Factor-D and Phosphorylated Platelet-Derived Growth Factor Receptor-Β after Traumatic Brain Injury in Rats

BACKGROUND

We explored the dynamic expression of platelet-derived growth factor-D (PDGF-D) and phosphorylated platelet-derived growth factor receptor-β (p-PDGFR-β) after traumatic brain injury in rats to provide theoretical basis for selecting therapeutic target and intervention time after traumatic brain injury.

METHODS

This study prepared the weight drop/impact acceleration-induced traumatic brain injury (TBI) model in rats, including sham group and TBI groups at different observation time points (6 hours, 12 hours, 24 hours, 3 days, and 7 days after TBI). The dynamic expression of PDGF-D and p-PDGFR-β after TBI were detected by western blot and immunofluorescence staining.

RESULTS

The expression level of PDGF-D and p-PDGFR-β after TBI was detected by western blot. The PDGF-D level was increased (p < 0.05) 6 hours after TBI and remained at the high level until 3 days after TBI (p < 0.05). The p-PDGFR-β level was increased (p < 0.05) 12 hours after TBI and remained at the high level until 3 days after TBI (p < 0.05). PDGF-D and p-PDGFR-β in brain tissues were found by immunofluorescence in the perihematoma area 24 hours after TBI.

CONCLUSIONS

This study revealed the expression phenomenon of PDGF-D and p-PDGFR-β after TBI in rats, suggesting that PDGF-D participates in the process of secondary brain injury after TBI through specific binding with PDGFR-β, which provides a theoretical basis for further research on selecting therapeutic targets and intervention times after TBI.

Role of Platelet-Derived Growth Factor on the Fibrosis Process in Thyroid Carcinoma: Evaluation by Shear Wave Elastography

OBJECTIVES

We aimed to determine the correlation between fibrosis and elastic values in papillary thyroid carcinoma (PTC) by shear wave elastography and to evaluate the effect of platelet-derived growth factor (PDGF) on the fibrosis process.

METHODS

Small interfering RNA (siRNA)-PDGF and normal BCPAP cell lines were injected subcutaneously into the backs of nude mice. The elastic values of all tumors were measured by shear wave elastography. The content of collagen fibers and the expression of PDGF and type IV collagen (COL4) were evaluated by Masson staining and western blotting.

RESULTS

There were 32 tumors in the control group and 30 tumors in the siRNA-PDGF group. The tumors were divided into 4 subgroups based on maximum diameters of the tumors. The mean elastic values ± SD (E_mean , 29.79 ± 11.04 kPa; E_min , 16.98 ± 7.51 kPa, E_max , 39.99 ± 15.30 kPa; and SD, 5.92 ± 2.00 kPa) in the siRNA-PDGF group were lower than in the control group (E_mean , 35.73 ± 18.49 kPa; E_min , 23.65 ± 14.92 kPa, E_max , 45.73 ± 22.88 kPa; and SD, 6.02 ± 3.38 kPa). The content of collagen fibers and the expression of platelet-derived growth factor B (PDGFB) and COL4 proteins in the siRNA-PDGF group were lower than in the control group (11.43% ± 6.99% and 19.80% ± 11.70%; P = .010; 0.14 ± 0.06 and 0.27 ± 0.10; P = .002; and 0.11 ± 0.06 and 0.15 ± 0.07; P = .101). The elastic values, collagen fiber content, and PDGFB and COL4 in the 4 subgroups gradually increased with the maximum diameter of tumors.

CONCLUSIONS

There was a positive correlation among PDGF, tumor stiffness, and fibrosis in the growth of PTC. Thus, PDGF might play an important role in the development of PTC.

Hepatic microenvironment underlies fibrosis in chronic hepatitis B patients

BACKGROUND

Chronic hepatitis B virus (HBV) infection is a leading cause of liver morbidity and mortality worldwide. Liver fibrosis resulting from viral infection-associated inflammation and direct liver damage plays an important role in disease management and prognostication. The mechanisms underlying the contribution of the liver microenvironment to fibrosis in HBV patients are not fully understood. There is an absence of effective clinical treatments for liver fibrosis progression; thus, establishing a suitable in vitro microenvironment in order to design novel therapeutics and identify molecular biomarkers to stratify patients is urgently required.

AIM

To examine a subset of pre-selected microenvironment factors of chronic HBV patients that may underlie fibrosis, with a focus on fibroblast activation.

METHODS

We examined the gene expression of key microenvironment factors in liver samples from patients with more advanced fibrosis compared with those with less severe fibrosis. We also used the human stellate cell line LX-2 in the in vitro study. Using different recombinant cytokines and growth factors or their combination, we studied how these factors interacted with LX-2 cells and pinpointed the cross-talk between the aforementioned factors and screened the most important factors.

RESULTS

Of the secreted factors examined, transforming growth factor (TGF)-β1, interleukin (IL)-1β and tumor necrosis factor (TNF)-α were increased in patients with advanced fibrosis. We found that besides TGF-β1, IL-1β can also induce a profibrotic cascade by stimulating the expression of connective tissue growth factor and platelet-derived growth factor (PDGF) in LX-2 cells. Furthermore, the proinflammatory response can be elicited in LX-2 cells following treatment with IL-1β and TNF-α, suggesting that stellate cells can respond to proinflammatory stimuli. By combining IL-1β and TGF-β1, we observed not only fibroblast activation as shown by αlpha-smooth muscle actin and PDGF induction, but also the inflammatory response as shown by increased expression of IL-1β.

CONCLUSION

Collectively, our data from HBV patients and in vitro studies demonstrate that the hepatic microenvironment plays an important role in mediating the crosstalk between profibrotic and proinflammatory responses and modulating fibrosis in chronic HBV patients. For the establishment of a suitable in vitro microenvironment for HBV-induced liver fibrosis, not only TGF-β1 but also IL-1β should be considered as a necessary environmental factor.

Electrical stimulation of whole blood for growth factor release and potential clinical implications

Clinicians have increasingly applied platelet-rich plasma (PRP) for wound healing treatments. Topical treatments commonly require biochemical agents such as bovine thrombin to activate PRP ex vivo for clotting and growth factor release to facilitate healing upon application to the wound of interest. Recent studies have explored electrical stimulation as an alternative to bovine thrombin for PRP activation due to the former's cost, workflow complexity and potentially significant side effects; however, both approaches require separating the PRP from whole blood (WB) prior to activation. Eliminating the separation (typically centrifugation) step would reduce the cost and duration of the clinical procedure, which may be critical in trauma and surgical applications. We hypothesize that electric pulses (EPs) can release growth factors from WB, as they do from PRP, without requiring centrifugation of WB into PRP. A pilot study for two donors demonstrates the potential for EP stimulated growth factor release from WB. This motivates future experiments assessing EP parameter optimization for WB activation and in vivo studies to determine the clinical benefits for topical treatments and, especially, for injections in orthopedic applications that already utilize non-treated/non-activated WB.

Human adipose-derived stem cell spheroids incorporating platelet-derived growth factor (PDGF) and bio-minerals for vascularized bone tissue engineering

Stem cells with mineralized materials have been used for bone regeneration; however, engineering the complex vascularized structure of the natural bone remains a challenge. Here, we developed platelet-derived growth factor (PDGF) and bio-mineral coated fibers which were then assembled with human adipose-derived stem cells (hADSCs) to form spheroids as building blocks for vascularized bone regeneration. The PDGF incorporated within the spheroid increased the proliferation of hADSCs, which was characterized by Ki-67 staining and DNA contents. Furthermore, the PDGF enhanced not only osteogenic differentiation, but also endothelial differentiation of hADSCs; the cells within the spheroids showed significantly greater gene expression by 2.46 ± 0.14 fold for osteocalcin (OCN) and by 12.85 ± 3.36 fold for von Willebrand factor (vWF) than those without PDGF. Finally, at two months following transplantation of PDGF-incorporated spheroids onto in vivo mouse calvarial defect, the regenerated bone area (42.48 ± 10.84%) was significantly enhanced and the greatest number of capillaries and arterioles with indication of transplanted hADSCs were observed. Moreover, millimeter-scale in vitro tissue prepared by fused assembly of the spheroids exhibited greater mRNA expression-associated to endothelial lineage. Taken together, these findings indicate that stem cell spheroids incorporating PDGF and bio-minerals could be used as a module for successful vascularized bone regeneration.

[Effect of transverse tibial bone transport on expression of serum angiogenesis-related growth factors]

OBJECTIVE

To investigate the effect of transverse tibial bone transport on the expression of angiogenesis-related growth factors in the serum of diabetic foot patients.

METHODS

Between January 2018 and December 2018, 10 patients who suffered from diabetes mellitus accompanied with Wagner stage 4 diabetic foot underwent transverse tibial bone transport. There were 5 males and 5 females with an average age of 59.2 years (range, 51-70 years). The duration of diabetes was 2-60 months, with an average of 24.2 months. The duration of diabetic foot was 30-120 days, with an average of 54.1 days. Peripheral venous blood was taken at 1 day before operation and at 1, 4, 11, 18, 28, and 35 days after operation. The serum was centrifuged and subjected to ELISA test to detect the expression levels of serum vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and platelet-derived growth factor (PDGF).

RESULTS

The levels of serum VEGF, bFGF, and EGF increased rapidly at 11 days after operation, and the expression levels of the factors at 11, 18, 28, and 35 days were significantly higher than those before operation ( P<0.05). The expression level of PDGF increased suddenly at 18 days after operation, and the expression level of PDGF at 18, 28, and 35 days was significantly higher than that before operation ( P<0.05).

CONCLUSION

Transverse tibial bone transport for the treatment of diabetic foot can significantly increase the expression of serum angiogenesis-related growth factors in early stage, which may be the mechanism of promoting the healing of diabetic foot wounds.

Autologous protein-based scaffold composed of platelet lysate and aminated hyaluronic acid

This study describes a protein-based scaffold using platelet rich plasma (PRP), aminated hyaluronic acid (HA-NH₂) and Genipin for potential use in regenerative applications as an autologous tissue engineering scaffold. Human PRP was subjected to three freeze-thaw cycles for obtaining platelet lysates (PL). HA-NH₂ was synthesized from hyaluronic acid. PL/HA-NH₂ scaffolds were fabricated using different concentrations of genipin (0.05, 0.1 and 0.2%) and HA-NH₂ (10, 20 and 30 mg/mL). Mechanical, physical, and chemical properties of the scaffolds were comprehensively investigated. The compressive test findings revealed that crosslinking with 0.1 and 0.2% genipin improved the mechanical properties of the scaffolds. SEM evaluations showed that the scaffolds exhibited an interconnected and macroporous structure. Besides, porosimetry analysis indicated a wide distribution of the scaffold pore-size. Rheological findings demonstrated that the G' values were higher than the G″ values, indicating that PL/HA-NH₂ scaffolds had typical viscoelastic properties. In vitro biocompatibility studies showed that the scaffolds were both cytocompatible and hemocompatible. Alamar Blue test indicated that human adipose mesenchymal stem cells (hASCs) were able to attach, spread and proliferate on the scaffolds for 21 days-duration. Our findings clearly indicate that PL/HA-NH₂ can be a promising autologous candidate scaffold for tissue engineering applications.

Deficiency of Mitochondrial Aspartate-Glutamate Carrier 1 Leads to Oligodendrocyte Precursor Cell Proliferation Defects Both In Vitro and In Vivo

Aspartate-Glutamate Carrier 1 (AGC1) deficiency is a rare neurological disease caused by mutations in the solute carrier family 25, member 12 (SLC25A12) gene, encoding for the mitochondrial aspartate-glutamate carrier isoform 1 (AGC1), a component of the malate-aspartate NADH shuttle (MAS), expressed in excitable tissues only. AGC1 deficiency patients are children showing severe hypotonia, arrested psychomotor development, seizures and global hypomyelination. While the effect of AGC1 deficiency in neurons and neuronal function has been deeply studied, little is known about oligodendrocytes and their precursors, the brain cells involved in myelination. Here we studied the effect of AGC1 down-regulation on oligodendrocyte precursor cells (OPCs), using both in vitro and in vivo mouse disease models. In the cell model, we showed that a reduced expression of AGC1 induces a deficit of OPC proliferation leading to their spontaneous and precocious differentiation into oligodendrocytes. Interestingly, this effect seems to be related to a dysregulation in the expression of trophic factors and receptors involved in OPC proliferation/differentiation, such as Platelet-Derived Growth Factor α (PDGFα) and Transforming Growth Factor βs (TGFβs). We also confirmed the OPC reduction in vivo in AGC1-deficent mice, as well as a proliferation deficit in neurospheres from the Subventricular Zone (SVZ) of these animals, thus indicating that AGC1 reduction could affect the proliferation of different brain precursor cells. These data clearly show that AGC1 impairment alters myelination not only by acting on N-acetyl-aspartate production in neurons but also on OPC proliferation and suggest new potential therapeutic targets for the treatment of AGC1 deficiency.

Nanoscale Robots Exhibiting Quorum Sensing

Multi-agent systems demonstrate the ability to collectively perform complex tasks (e.g., construction, search, and locomotion) with greater speed, efficiency, or effectiveness than could a single agent alone. Direct and indirect coordination methods allow agents to collaborate to share information and adapt their activity to fit dynamic situations. A well-studied example is quorum sensing (QS), a mechanism allowing bacterial communities to coordinate and optimize various phenotypes in response to population density. Here we implement, for the first time, bio-inspired QS in robots fabricated from DNA origami, which communicate by transmitting and receiving diffusing signals. The mechanism we describe includes features such as programmable response thresholds and quorum quenching, and is capable of being triggered by proximity of a specific target cell. Nanoscale robots with swarm intelligence could carry out tasks that have been so far unachievable in diverse fields such as industry, manufacturing, and medicine.

Platelet-rich Plasma and Other Hemocomponents in Veterinary Regenerative Medicine

Platelet-rich plasma, platelet-rich fibrin, fibrin glue, and platelet lysate are the most widely used nontransfusional hemocomponents that, as biological and therapeutic aids, enhance the physiological reactions after an injury to facilitate the repair and regeneration processes. Recently, this type of therapy also has significantly expanded in veterinary medicine. Due to many similarities, the animal patient could be a good reference as a study model for humans, especially for chronic and difficult-to-heal injuries. This review discusses the current state of hemocomponent use for topical application in veterinary medicine, with a comparison with human medicine.

Making Breast Tumors Tamoxifen-Sensitive

A new study offers a potential treatment strategy for basal-like breast tumors. Researchers found that disrupting platelet-derived growth factor signaling-either genetically or with an antibody that blocks one form of the growth factor-can cause tumors to change to the luminal subtype, which is susceptible to antiestrogen therapies.

Receptor tyrosine kinase expression and phosphorylation in canine nasal carcinoma

Preliminary studies have supported use of toceranib phosphate (Palladia®) in treatment of canine nasal carcinomas, though the mechanisms of its activity are unknown. This study evaluated sixteen canine nasal carcinoma and five normal nasal epithelium samples for expression and phosphorylation of known targets of toceranib [vascular endothelial growth factor receptor-2 (VEGR2), platelet derived growth factor alpha (PDGFR-α), platelet derived growth factor receptor beta (PDGFR-β), and stem cell factor receptor (c-KIT)] and epidermal growth factor receptor 1 (EGFR1) using immunohistochemistry, RT-PCR and a receptor tyrosine kinase (RTK) phosphorylation panel. Protein for VEGFR2 was expressed in all carcinomas, PDGFR-α was noted in 15/16, whereas PDGFR-β was detected in 3/16 samples, but showed significant stromal staining. Protein expression for c-KIT was present in 4/16 and EGFR1 was noted in 14/16 samples. Normal tissue showed variable protein expression of the RTKs. Messenger RNA for VEGFR2, PDGFR-β, and c-KIT were noted in all samples. Messenger RNA for PDGFR-α and EGFR1 were detected in 15/16 samples. All normal nasal tissue detected messenger RNA. Phosphorylation of VEGFR2, PDGFR-α, PDGFR-β and c-KIT was not observed in any carcinoma or normal nasal sample, but phosphorylation of EGFR1 was noted in 10/16 carcinoma and 3/5 normal samples. The absence of phosphorylated RTK targets of toceranib suggests any clinical effect of toceranib occurs through inhibition of alternative unidentified RTK pathways in canine nasal carcinomas. The observed protein and message expression and phosphorylation of EGFR1 in the nasal carcinoma samples merits further inquiry into EGFR1 as a therapeutic target for this cancer.

Protein Recognition by Phase Transition of Aptamer-Linked Polythiophene Single Nanowire

A novel protein recognition platform is developed using aptamer-linked polythiophene nanowires. As the aptamer functionalized poly (3-methylthiophene) nanowire is treated by the specific protein, resonance Raman and photoluminescence signals are simultaneously enhanced. Statistical analyses deliver the capability of a single conjugated polymer nanowire with phase-transition characteristics in response to selectivity and concentration.

Effectiveness of Imatinib Mesylate Treatment in a Patient with Dermatofibrosarcoma Protuberans with Pulmonary and Pancreatic Metastases

We herein encountered a case of abdominal wall dermatofibrosarcoma protuberans (DFSP) that developed pulmonary and pancreatic metastases 5 years after complete resection. Because specific rearrangements of the platelet-derived growth factor beta (PDGFB) locus by a novel fluorescence in situ hybridization method was detected, the patient was treated with imatinib mesylate at 400 mg/day. A partial response was achieved by imatinib without any specific toxicity. Although metastatic DFSP is an extremely rare disease, an evaluation of PDGFB fusion is essential and imatinib mesylate should be considered as an optimal therapeutic choice in patients with metastatic or locally advanced DFSP.

[mRNA-binding protein Human-antigen R regulates α-SMA expression in human bronchia smooth muscle cells]

OBJECTIVE

To investigate the role of mRNA binding protein Human-antigen R (HuR) in the over-expression of α-Smooth muscle actin (α-SMA) stimulated by Platelet-derived Growth Factor (PDGF) in cultured human bronchia smooth muscle cells.

METHODS

Human bronchia smooth muscle cells cultured in vitro were divided into 0, 6, 12 and 24 h groups according to the time of PDGF treatment. Total HuR protein and total α-SMA protein expression were detected by Western blot. Total HuR mRNA and total α-SMA mRNA level were determined by quantitative real time-polymerase chain reaction. RNA interference technology was used to down-regulate HuR protein level to study the protective effect of HuR in PDGF-stimulated α-SMA protein expression.

RESULTS

PDGF up-regulated the expression of HuR in a time-dependent manner. The relative expression levels of whole-cell HuR protein and mRNA in 0, 6, 12, 24 h groups were 0.23±0.09, 0.42±0.11, 0.93±0.21, 1.37±0.28; 1.00±0.00, 1.09±0.03, 1.16±0.03, 1.27±0.02 (all P<0.05). The relative expression levels of α-SMA protein and mRNA in 0, 6, 12, 24 h group also showed an increase trend marked in a time-dependent manner (1.03±0.08, 1.20±0.09, 1.39±0.11, 1.58±0.10; 1.00±0.00, 1.17±0.02, 1.23±0.02, 1.45±0.03; all P<0.05). Using RNA interference technology to down-regulate HuR protein level, there was a decrease in α-SMA protein expression.

CONCLUSION

PDGF stimulation can increase the expression of HuR and α-SMA in the smooth muscle cells, and HuR protein is involved in the expression of α-SMA protein stimulated by PDGF.

[Effect of Chlorogenic Acid on Hepatic Stellate Cell Proliferation, Generation and Degradation of Extracelluar Matrix]

OBJECTIVE

To investigate the effects of chlorogenic acid (CGA) on hepatic stellate cell proliferation and the expression and secretion of Collagen I, Collagen III, tissue inhibitors of metalloproteinase-1 (TIMP-1) and matrix metalloproteinase-2 (MMP-2).

METHODS

An immortalized rat hepatic stellate cell (HSC) line was cultured in vitro. The cells were divided into 5 groups: control group; platelet-derived growth factor (PDGF) (10 ng/mL), PDGF+CGA (12.5 µg/mL), PDGF+CGA (25 µg/mL), PDGF+CGA (50 µg/mL) and CGA (50 µg/mL) group. After 24 hours treatment, the proliferation of HSC was detected by MTT method. The mRNA expression of Collagen I, Collagen III, TIMP-1 and MMP-2 were detected by RT-PCR. The protein levels of Collagen I, Collagen III, TIMP-1 and MMP-2 in the culture supernatant of HSC were measured by ELISA.

RESULTS

PDGF increased the hepatic stellate cell proliferation, the mRNA expression and the protein levels of Collagen I, Collagen III and TIMP-1. (P < 0.05), which were significantly decreased by CGA (P < 0. 05). However, CGA had no significant influence on the expression of MMP-2.

CONCLUSION

The antifibrotic effect of CGA may be related with the inhibition of hepatic stellate cell proliferation and generation of extracelluar matrix and promotion of extracelluar matrix degradation.

[Endothelial progenitor cells promote osteogenic differentiation of marrow stromal cells in a paracrine manner]

OBJECTIVE

To explore the mechanisms of endothelial progenitor cells (EPCs)on promoting osteogenic differentiation of marrow stromal cells (MSCs).

METHODS

EPCs and MSCs were isolated and cultured successfully from C57BL/7 murine bone marrow by in vitro amplification. EPC-conditioned medium (CM) was extracted to detect the concentrations of vascular endothelial growth factor (VEGF), transforming growth factor-beta 1 (TGFβ1), platelet-derived growth factor (PDGF), insulin-like growth factor 1 (IGF-1), stromal cell-derived factor 1 (SDF-1) and basic fibroblast growth factor (bFGF) by enzyme-linked immunosorbent assay (ELISA). After 14 days of induction, alizarin red staining was used to detect every group's calcium salt deposition. And analyses were conducted for the effects of above mentioned antibodies of cytokines on osteogenic differentiation of MSCs.

RESULTS

Positive rates of EPCs were 79.3%, 79.5%, 76.4% for VEGFR2, CD34 and CD133 respectively, and EPCs could form tube-like structure on matrigel. EPCs secreted VEGF, TGFβ1, PDGF, IGF-1, SDF-1 and bFGF. MSC/EPC group formed more mineralized nodules than MSC group, and semi-quantitative results showed the optical density of MSC/EPC group was higher than that of MSC group (0.733 ± 0.032 vs 0.236 ± 0.020, P < 0.001). The number of formed mineralized nodules of 50% EPC-CM group were more than those of 25% EPC-CM group, and semi-quantitative results showed that the optical density of 50% EPC-CM group was higher than that of 25% EPC-CM group (0.637 ± 0.028 vs 0.336 ± 0.024, P < 0.001), the number of formed mineralized nodules of 25% EPC-CM group were more than those of 0 EPC-CM group, and semi-quantitative results showed that the optical density of 25% EPC-CM group was higher than that of 0 EPC-CM group (0.336 ± 0.024 vs 0.239 ± 0.013, P = 0.004). On the basis of 50% of EPC-CM, the number of formed mineralized nodules significantly declined in the presence of anti-VEGF antibody, anti-TGFβ1 antibody, anti-IGF-1 antibody (P < 0.01).

CONCLUSION

EPCs promote osteogenic differentiation of MSCs probably through the paracrine effects of VEGF, TGFβ1 and IGF-1.

The cancer-associated fibroblasts and drug resistance

The present treatment of solid tumors is plagued by drug resistance. Despite continued development of meticulously designed therapeutic scheme, cancer cells remain poorly being completely eliminated. Because therapeutic resistance is a problem with the drug used in cancer therapy, most of the studies about the drugs resistance have focused on the role of epithelial cancer cells themselves. However, it is becoming increasingly apparent that tumor microenvironment could provide a shelter for tumor cells which keep their survival after initial drug exposure. Cancer-associated fibroblasts (CAFs) are the crucial component of the tumor microenvironment; substantial evidence suggests that the CAFs mediate resistance of solid tumor cells to the anticancer drugs. In this review, we describe how the CAFs may be involved in the resistance of tumor cells to the therapeutic agents and present some of the emerging therapeutic targets for modulation this resistant phenotype.

[Synergistic effect of platelet-derived growth factor-BB and transforming growth factor-beta1, on expression of integrin beta3 in periodontal membrane of rat orthodontic tooth]

OBJECTIVE

To investigate the synergistic effect of transforming growth factor-beta1 (TGF-beta1) and platelet-derived growth factor-BB (PDGF-BB) on the expression of integrin beta3, in periodontal membrane of rat orthodontic tooth.

METHODS

An orthodontic tooth movement model was established. Up to 32 experimental rats were randomly divided into four groups according to a random number table. The four groups were injected with 1% PBS, TGF-beta1 (5 ng), PDGF-BB (10 ng), and combined TGF-beta1 (5 ng) and PDGF-BB (10 ng) in the buccal submucosal, respectively. The volume injected in each group was 0.1 mL. The animals were then sacrificed on the 10th day. The left maxillary first molar and periodontal tissue were taken. Different expressions of integrin beta3 were detected in periodontal tissues through immunohistochemistry. Mean optical density (OD) values of the positive fields were examined. The data obtained were analyzed through ANOVA. The data followed normal distribution, and were compared via t-test.

RESULTS

Compared with the control groups, the expression of integrin beta3 was higher in the experimental groupin tension sides (P < 0.01). Significant differences in tension sides between the single-injection groups and the combined group were observed (P < 0.01). Compared with the control groups, the expression of integrin beta3 was higher in the experimental group in compression sides (P < 0.05). In addition, there was no significant differences in compression sides between the single-injection groups and the combined group (P > 0.05).

CONCLUSION

In terms of local regulatory factors, TGF-beta1 combined with PDGF-BB enhance the expression of integrin beta3 in the periodontal membrane and accelerate periodontal remodeling. The synergistic effect of the two growth factors is better than the single growth factor.