Explore the vast range of titles available.

Platelet‐Derived Growth Factors (PDGFs) and Transforming Growth Factor β (TGFβ) are pivotal in orchestrating the complex wound healing process, particularly in granulation tissue formation. This review aims to comprehensively examine the roles of PDGF alongisde TGFβ in granulation tissue formation and their implications for abnormal wound healing. PDGFs, as homodimeric or heterodimeric combinations, such that PDGF‐AA, PDGF‐AB and PDGF‐BB stimulate fibroblast proliferation and extracellular matrix synthesis, which is crucial for tissue repair. TGFβ, with its three isoforms, influences granulation tissue through diverse functions, with TGFβ‐1 pivotal in fibrosis formation. Understanding their signalling pathways, notably PDGF's engagement with PDGF receptors and subsequent activation of cellular pathways, illuminates their roles in wound healing cascades. Excessive granulation, a complication of abnormal wound healing, involves dysregulated PDGF and TGFβ activity, leading to hypertrophic scar formation. Clinical management, particularly in ophthalmology, addresses excessive granulation's impact on procedures like endo‐dacryocystorhinostomy. Strategies employing steroid agents and Mitomycin‐C aim to mitigate ostium granulation. The potential use of PDGF receptor blockers, such as olaratumab, warrants further investigation for managing excessive granulation. In conclusion, PDGF and TGFβ emerge as critical regulators in granulation tissue formation, underscoring their significance in wound healing processes and offering avenues for therapeutic intervention.

Hippocampal circuitry stimulation is sufficient to regulate adult hippocampal neurogenesis and ameliorate depressive‐like behavior, but its underlying mechanism remains unclear. Here, it is shown that inhibition of medial septum (MS)‐dentate gyrus (DG) circuit reverses the chronic social defeat stress (CSDS)‐induced depression‐like behavior. Further analysis exhibits that inhibition of gamma‐aminobutyric acidergic neurons in MS projecting to the DG (MSGABA+‐DG) increases the expression of platelet‐derived growth factor‐BB (PDGF‐BB) in somatostatin (SOM) positive interneurons of DG, which contributes to the antidepressant‐like effects. Overexpression of the PDGF‐BB or exogenous administration of PDGF‐BB in DG rescues the effect of chronic stress on the inhibition of neural stem cells (NSCs) proliferation and dendritic growth of adult‐born hippocampal neurons, as well as on depressive‐like behaviors. Conversely, knockdown of PDGF‐BB facilitates CSDS‐induced deficit of hippocampal neurogenesis and promotes the susceptibility to chronic stress in mice. Finally, conditional knockdown platelet‐derived growth factor receptor beta (PDGFRβ) in NSCs blocks an increase in NSCs proliferation and the antidepressant effects of PDGF‐BB. These results delineate a previously unidentified PDGF‐BB/PDGFRβ signaling in regulating depressive‐like behaviors and identify a novel mechanism by which the MSGABA+‐DG pathway regulates the expression of PDGF‐BB in SOM‐positive interneurons. The study describes the functional connectivity in the MSGABA+‐DG circuit and the novel downstream molecule PDGF‐BB. Inhibition of MSGABA+‐DG pathway increases the expression of PDGF‐BB in SOM‐positive interneurons, which is capable of enhancing adult hippocampal neurogenesis in a PDGFRβ‐dependent manner by activating the Janus kinase‐signal transducer 2 and activator of transcription 3 (JAK2/STAT3) signaling pathway, leading to the improvement of chronic stress‐induced depressive‐like behavior.

Osteoporosis is one of the most common metabolic bone diseases affecting millions of people. We previously found that harmine prevents bone loss in ovariectomized mice via increasing preosteoclast platelet‐derived growth factor‐BB (PDGF‐BB) production and type H vessel formation. However, the molecular mechanisms by which harmine promotes preosteoclast PDGF‐BB generation are still unclear. In this study, we revealed that inhibitor of DNA binding‐2 (Id2) and activator protein‐1 (AP‐1) were important factors implicated in harmine‐enhanced preosteoclast PDGF‐BB production. Exposure of RANKL‐induced Primary bone marrow macrophages (BMMs), isolated from tibiae and femora of mice, to harmine increased the protein levels of Id2 and AP‐1. Knockdown of Id2 by Id2‐siRNA reduced the number of preosteoclasts as well as secretion of PDGF‐BB in RANKL‐stimulated BMMs administrated with harmine. Inhibition of c‐Fos or c‐Jun (components of AP‐1) both reversed the stimulatory effect of harmine on preosteoclast PDGF‐BB production. Dual‐luciferase reporter assay analyses determined that PDGF‐BB was the direct target of AP‐1 which was up‐regulated by harmine treatment. In conclusion, our data demonstrated a novel mechanism involving in the production of PDGF‐BB increased by harmine, which may provide potential therapeutic targets for bone loss diseases.

Increased immature neovessels contribute to plaque growth and instability. Here, we investigated a method to establish functional and stable neovessel networks to increase plaque stability. Rabbits underwent aortic balloon injury and were divided into six groups: sham, vector and lentiviral transfection with vascular endothelial growth factor‐A (VEGF)‐A, fibroblast growth factor (FGF)‐2, platelet‐derived growth factor (PDGF)‐BB and FGF‐2 + PDGF‐BB. Lentivirus was percutaneously injected into the media‐adventitia of the abdominal aorta by intravascular ultrasound guidance, and plaque‐rupture rate, plaque‐vulnerability index and plaque neovessel density at the injection site were evaluated. Confocal microscopy, Prussian Blue assay, Evans Blue, immunofluorescence and transmission electron microscopy were used to assess neovessel function and pericyte coverage. To evaluate the effect of FGF‐2/PDGF‐BB on pericyte migration, we used the mesenchymal progenitor cell line 10T1/2 as an in vitro model. VEGF‐A‐ and FGF‐2‐overexpression increased the number of immature neovessels, which caused intraplaque haemorrhage and inflammatory cell infiltration, eventually resulting in the plaque vulnerability; however, FGF‐2/PDGF‐BB induced mature and functional neovessels, through increased neovessel pericyte coverage. Additionally, in vitro analysis of 10T1/2 cells revealed that FGF‐2/PDGF‐BB induced epsin‐2 expression and enhanced the VEGF receptor‐2 degradation, which negatively regulated pericyte function consistent with the in vivo data. These results showed that the combination of FGF‐2 and PDGF‐BB promoted the function and maturation of plaque neovessels, thereby representing a novel potential treatment strategy for vulnerable plaques.

Aims The neurotropic growth factor PDGF‐BB was shown to have vital neurorestorative functions in various animal models of Parkinson's disease (PD). Previous studies indicated that the regenerative property of PDGF‐BB contributes to the increased intensity of tyrosine hydroxylase (TH) fibers in vivo. However, whether PDGF‐BB directly modulates the expression of TH, and the underlying mechanism is still unknown. We will carefully examine this in our current study. Method MPTP‐lesion mice received PDGF‐BB treatment via intracerebroventricular (i.c.v) administration, and the expression of TH in different brain regions was assessed by RT‐PCR, Western blot, and immunohistochemistry staining. The molecular mechanisms of PDGF‐BB‐mediated TH upregulation were examined by RT‐PCR, Western blot, ChIP assay, luciferase reporter assay, and immunocytochemistry. Results We validated a reversal expression of TH in MPTP‐lesion mice upon i.c.v administration of PDGF‐BB for seven days. Similar effects of PDGF‐BB‐mediated TH upregulation were also observed in MPP+‐treated primary neuronal culture and dopaminergic neuronal cell line SH‐SY5Y cells. We next demonstrated that PDGF‐BB rapidly activated the pro‐survival PI3K/Akt and MAPK/ERK signaling pathways, as well as the downstream CREB in SH‐SY5Y cells. We further confirmed the significant induction of p‐CREB in PDGF‐BB‐treated animals in vivo. Using a genetic approach, we demonstrated that the transcription factor CREB is critical for PDGF‐BB‐mediated TH expression. The activation and nucleus translocation of CREB were promoted in PDGF‐BB‐treated SH‐SY5Y cells, and the enrichment of CREB on the promoter region of TH gene was also increased upon PDGF‐BB treatment. Conclusion Our data demonstrated that PDGF‐BB directly regulated the expression of TH via activating the downstream Akt/ERK/CREB signaling pathways. Our finding will further support the therapeutic potential of PDGF‐BB in PD, and provide the possibility that targeting PDGF signaling can be harnessed as an adjunctive therapy in PD in the future. The binding of PDGF‐BB to its receptor in DA neurons leads to the activation of downstream PI3K/Akt and MAPK/ERK signaling pathways, which trigger the nucleus translocation of the transcription factor CREB and increased expression of tyrosine hydroxylase.

Osteoporotic bone defects are challenging to repair due to imbalances in bone resorption and formation, coupled with insufficient vascularization. To address these issues, it develops a trifunctional hydrogel (SF‐ZIF@NA) designed to selectively inhibit osteoclast activity and enhance vascularized bone regeneration. By enzymatically removing sialic acid, SF‐ZIF@NA prevents precursor osteoclasts (pOCs) from fusing into bone‐resorbing mature osteoclasts (mOCs), thereby preserving pOCs and their anabolic functions. Additionally, the hydrogel releases Zinc ion (Zn2⁺) in response to acidic conditions, promoting osteogenesis and angiogenesis. In vitro results confirmed that SF‐ZIF@NA impedes osteoclast fusion, enhances platelet‐derived growth factor‐BB (PDGF‐BB secretion from pOCs, and activates the FAK (focal adhesion kinase) signaling pathway to stimulate vascularized bone formation. In osteoporotic bone defect models, SF‐ZIF@NA accelerated bone repair with increased bone density and vascularization. These findings demonstrate that SF‐ZIF@NA offers a targeted and multifunctional strategy for osteoporotic bone regeneration by concurrently modulating osteoclast activity and promoting angiogenesis. This study introduces the SF‐ZIF@NA hydrogel system for osteoporotic bone defect treatment. The hydrogel inhibits osteoclast fusion by removing sialic acid and preserves the anabolic function of precursor osteoclasts (pOCs). It also releases Zn2⁺ in acidic conditions, promoting osteogenesis and angiogenesis. Together, these effects accelerate the repair of osteoporotic bone defects, improving bone regeneration and vascularization.

Background Abnormally high shear stress (HSS) is strongly associated with intracranial aneurysm (IA) formation. Endothelial Piezo1 is sensitive to shear stress stimulation, but the mechanism by which it mediates this mechanobiological coupling process is unclear. Methods The correlation between shear stress and the Piezo1 expression was investigated using human IA samples and a parallel‐plate flow chamber system. To determine the effects of endothelial Piezo1 on the phenotype of neighboring vascular smooth muscle cells (VSMCs) and IA formation, the CRISPR/Cas9 system was used to inhibit endothelial Piezo1 gene expression in vitro. Piezo1ΔEC mice were produced by injecting AAV2‐BR1‐Tie2‐Cre into 8‐week‐old male Piezo1flox/flox mice, which were further used to construct the IA mouse model. Single‐cell RNA sequencing and intercellular communication analyses of co‐cultured endothelial cells (ECs) and VSMCs were used to screen for receptor‐ligand pairs after inhibiting EC Piezo1 in vitro. The role of the screened receptor‐ligand pair was further validated via in vivo and in vitro experiments. Additionally, the underlying mechanisms were investigated. Result Piezo1 expression correlated negatively with the shear stress in human IA. HSS reduced EC Piezo1 expression and promoted VSMC phenotypic transformation compared with physiological shear stress. Depletion of EC Piezo1 resulted in the VSMC phenotypic transformation and, more importantly, promoted aneurysmal vascular remodeling in the mouse IA model. The platelet‐derived growth factor subunit B (PDGFB)_Platelet‐derived growth factor receptor β (PDGFRβ) was identified as being involved in this process. Moreover, the PDGFRβ antagonist reversed the VSMC phenotypic transformation and attenuated IA progression. Mechanistically, Piezo1 depletion promoted PDGFB expression via YAP/β‐catenin pathway. Conclusion HSS downregulates Piezo1 expression in ECs, which subsequently enhances PDGF‐BB expression through the YAP/β‐catenin signaling pathway. The elevated PDGF‐BB facilitates phenotypic transition of VSMCs via PDGFRβ binding, ultimately contributing to IA formation. HSS downregulates Piezo1 expression in ECs, which subsequently enhances PDGF‐BB expression through the YAP/β‐catenin signaling pathway. The elevated PDGF‐BB facilitates phenotypic transition of VSMCs via PDGFRβ binding, ultimately contributing to IA formation.

Chronic wounds represent a major challenge to the present healthcare system. In recent decades, many topical therapies have been investigated for the treatment of chronic wounds, including different types of wound dressings, antimicrobial agents, and cell therapy. Platelet-derived growth factor (PDGF) plays an important role in wound healing and has been approved for treatment of wounds related to diabetes mellitus. However, the high cost and short retention time of PDGF protein have limited its wide application. To overcome this challenge, we designed a PDGF-mimicking peptide by connecting PDGF epitope VRKIEIVRKK and self-assembling motif derived from β-amyloid peptide. The resultant peptide can self-assemble into a fibril-rich network and leads to supramolecular hydrogelation with good stability. The hydrophilic epitope can be exposed on the surface of nanofibrils, which might contribute to the binding and activation of PDGF receptors. The forming hydrogel is able to induce the growth and migration of vascular endothelial cells and promote the formation of vascular branches. In the full-thickness skin wounds of healthy mice, after the application of the hydrogel, the density of neovascularization marked by CD31 was greater than that in the control group on Day 3. Larger collagen deposition and a thicker epidermis were observed on Day 12. These results demonstrate that the hydrogel can stimulate collagen deposition and angiogenesis, enhance skin regeneration, and show an excellent therapeutic effect. Taken together, this work not only provides new insight into the design of bioactive peptides but also offers a promising biomaterial for wound healing.

VEGF induces normal or aberrant angiogenesis depending on its dose in the microenvironment around each producing cell in vivo. This transition depends on the balance between VEGF-induced endothelial stimulation and PDGF-BB-mediated pericyte recruitment, and co-expression of PDGF-BB normalizes aberrant angiogenesis despite high VEGF doses. We recently found that VEGF over-expression induces angiogenesis in skeletal muscle through an initial circumferential vascular enlargement followed by longitudinal splitting, rather than sprouting. Here we investigated the cellular mechanism by which PDGF-BB co-expression normalizes VEGF-induced aberrant angiogenesis. Monoclonal populations of transduced myoblasts, expressing similarly high levels of VEGF alone or with PDGF-BB, were implanted in mouse skeletal muscles. PDGF-BB co-expression did not promote sprouting and angiogenesis that occurred through vascular enlargement and splitting. However, enlargements were significantly smaller in diameter, due to a significant reduction in endothelial proliferation, and retained pericytes, which were otherwise lost with high VEGF alone. A time-course of histological analyses and repetitive intravital imaging showed that PDGF-BB co-expression anticipated the initiation of vascular enlargement and markedly accelerated the splitting process. Interestingly, quantification during in vivo imaging suggested that a global reduction in shear stress favored the initiation of transluminal pillar formation during VEGF-induced splitting angiogenesis. Quantification of target gene expression showed that VEGF-R2 signaling output was significantly reduced by PDGF-BB co-expression compared to VEGF alone. In conclusion, PDGF-BB co-expression prevents VEGF-induced aberrant angiogenesis by modulating VEGF-R2 signaling and endothelial proliferation, thereby limiting the degree of circumferential enlargement and enabling efficient completion of vascular splitting into normal capillary networks despite high VEGF doses.

RNA‐binding properties of nucleolin play a fundamental role in regulating cell growth and proliferation. We have previously shown that nucleolin plays an important regulatory role in the phenotypic transformation of vascular smooth muscle cells (VSMCs) induced by angiotensin II (Ang II). In the present study, we aimed to investigate the molecular mechanism of nucleolin‐mediated phenotypic transformation of VSMCs induced by Ang II. Epidermal growth factor (EGF) and platelet‐derived growth factor (PDGF) inhibitors were used to observe the effect of Ang II on phenotypic transformation of VSMCs. The regulatory role of nucleolin in the phenotypic transformation of VSMCs was identified by nucleolin gene mutation, gene overexpression and RNA interference technology. Moreover, we elucidated the molecular mechanism underlying the regulatory effect of nucleolin on phenotypic transformation of VSMCs. EGF and PDGF‐BB played an important role in the phenotypic transformation of VSMCs induced by Ang II. Nucleolin exerted a positive regulatory effect on the expression and secretion of EGF and PDGF‐BB. In addition, nucleolin could bind to the 5′ untranslated region (UTR) of EGF and PDGF‐BB mRNA, and such binding up‐regulated the stability and expression of EGF and PDGF‐BB mRNA, promoting Ang II‐induced phenotypic transformation of VSMCs.