YY1 lactylation in microglia promotes angiogenesis through transcription activation-mediated upregulation of FGF2

Ocular neovascularization is a leading cause of blindness. Retinal microglia have been implicated in hypoxia-induced angiogenesis and vasculopathy, but the underlying mechanisms remain largely unknown. Here, we report that lactylation in microglia is critical for retinal neovascularization. Using lactylome and proteomic analyses, we identified a list of hyperlactylated proteins in the context of increased lactate under hypoxia. Yin Yang-1 (YY1), a transcription factor, is lactylated at lysine 183 (K183) under hypoxia, which is regulated by p300. Furthermore, hyperlactylated YY1 directly enhances fibroblast growth factor 2 (FGF2) transcription and promotes angiogenesis. YY1 mutation at K183 eliminates these effects. Notably, clinical retrospective analysis shows that lactate concentrations in retinopathy of prematurity (ROP) infants are significantly increased compared with those in controls. Taken together, our results demonstrate that YY1 lactylation in microglia promotes FGF2 expression and plays a pivotal proangiogenic role, providing new insights into retinal neovascular diseases.

Investigating the Anti-Angiogenic Effects of Elaeagnus angustifolia L. Extract in Vivo

Background: Angiogenesis is the formation of new blood vessels from pre-existing ones. It occurs in both physiological and pathological conditions. Objectives: We aimed to evaluate the antiangiogenic effect of Elaeagnus angustifolia L. water extract in vivo to determine any anti-proliferative effect of the extract on the A549 lung cancer cell line, and to investigate its effect on VEGF-A and FGF2 expression in the A549 cell line. Methods: Trypan blue exclusion test was implemented to establish any possible anti-proliferative effect of the extract. Then, Matrigel plug assay was performed on mice using the same cell line to test the antiangiogenic effect of the extract. Finally, A549 cells were treated with the extract at concentrations of 25, 12.5, and 6.25 µg/ml to investigate the changes in VEGF-A and FGF2 expression by RT-qPCR. Results: E. angustifolia extract did not exhibit a significant anti-proliferative effect against A549 cells. The extract at concentrations of 12.5 and 6.25 µg/ml demonstrated an inhibitory effect against the growth of new blood vessels by 75.63 and 45.26%, respectively. The extract did not affect the expression of VEGF-A and FGF2 in A549 cells. Conclusion: Our findings show that water extract of E. angustifolia possesses potent antiangiogenic activity, while neither exhibiting significant anti-proliferative effect nor affecting VEGF-A or FGF2 expression in the A459 cell line, suggesting either sole direct antiangiogenic effect, or both direct and indirect effects with paracrine suppression of other genes.

G-MDSCs promote aging-related cardiac fibrosis by activating myofibroblasts and preventing senescence

Aging is one of the most prominent risk factors for heart failure. Myeloid-derived suppressor cells (MDSCs) accumulate in aged tissue and have been confirmed to be associated with various aging-related diseases. However, the role of MDSCs in the aging heart remains unknown. Through RNA-seq and biochemical approaches, we found that granulocytic MDSCs (G-MDSCs) accumulated significantly in the aging heart compared with monocytic MDSCs (M-MDSCs). Therefore, we explored the effects of G-MDSCs on the aging heart. We found that the adoptive transfer of G-MDSCs of aging mice to young hearts resulted in cardiac diastolic dysfunction by inducing cardiac fibrosis, similar to that in aging hearts. S100A8/A9 derived from G-MDSCs induced inflammatory phenotypes and increased the osteopontin (OPN) level in fibroblasts. The upregulation of fibroblast growth factor 2 (FGF2) expression in fibroblasts mediated by G-MDSCs promoted antisenescence and antiapoptotic phenotypes of fibroblasts. SOX9 is the downstream gene of FGF2 and is required for FGF2-mediated and G-MDSC-mediated profibrotic effects. Interestingly, both FGF2 levels and SOX9 levels were upregulated in fibroblasts but not in G-MDSCs and were independent of S100A8/9. Therefore, a novel FGF2-SOX9 signaling axis that regulates fibroblast self-renewal and antiapoptotic phenotypes was identified. Our study revealed the mechanism by which G-MDSCs promote cardiac fibrosis via the secretion of S100A8/A9 and the regulation of FGF2-SOX9 signaling in fibroblasts during aging.

FGF/FGFR Pathways in Multiple Sclerosis and in Its Disease Models

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS) affecting more than two million people worldwide. In MS, oligodendrocytes and myelin sheaths are destroyed by autoimmune-mediated inflammation, while remyelination is impaired. Recent investigations of post-mortem tissue suggest that Fibroblast growth factor (FGF) signaling may regulate inflammation and myelination in MS. FGF2 expression seems to correlate positively with macrophages/microglia and negatively with myelination; FGF1 was suggested to promote remyelination. In myelin oligodendrocyte glycoprotein (MOG)35–55-induced experimental autoimmune encephalomyelitis (EAE), systemic deletion of FGF2 suggested that FGF2 may promote remyelination. Specific deletion of FGF receptors (FGFRs) in oligodendrocytes in this EAE model resulted in a decrease of lymphocyte and macrophage/microglia infiltration as well as myelin and axon degeneration. These effects were mediated by ERK/Akt phosphorylation, a brain-derived neurotrophic factor, and downregulation of inhibitors of remyelination. In the first part of this review, the most important pharmacotherapeutic principles for MS will be illustrated, and then we will review recent advances made on FGF signaling in MS. Thus, we will suggest application of FGFR inhibitors, which are currently used in Phase II and III cancer trials, as a therapeutic option to reduce inflammation and induce remyelination in EAE and eventually MS.

Circular RNA HIPK3 plays a carcinogenic role in cervical cancer progression via regulating miR-485-3p/FGF2 axis

Circular RNA (circRNA) is an endogenous RNA molecule with a stable closed-loop structure. The circular RNA HIPK3 (circHIPK3) is highly expressed in hepatocellular carcinoma and facilitates tumor growth. However, its role in cervical cancer (CC) and its regulatory mechanisms are not well-studied. This study aimed for investigating the function of circHIPK3 on proliferation and metastasis of CC cells. In this study, quantitative real-time PCR assay was adopted to delve into the circHIPK3 expression in CC cell lines. Cell counting kit-8 and colony formation assays were used to evaluate the influence of overexpression and knockdown of circHIPK3 on CC cell proliferation. Dual-luciferase reporter assay was employed to probe into the binding of miR-485-3p to circHIPK3 and miR-485-3p to the 3’ untranslated region (UTR) of fibroblast growth factor 2 (FGF2), respectively. FGF2 protein expression was detected by western blot analysis. This study confirmed that circHIPK3 was highly expressed in CC tissues. Overexpressed circHIPK3 could remarkably expedite the proliferation, migration and invasion of SiHa cells, and knocking down circHIPK3 could significantly impede the proliferation, migration and invasion of HeLa cells. MiR-485-3p can directly bind to circHIPK3 and the 3’UTR of FGF2. Overexpression of circHIPK3 triggered the upregulation of FGF2 expression while knockdown of circHIPK3 reduced FGF2 expression in CC cells, and the transfection of miR-485-3p mimics reversed the upregulation of FGF2 expression and enhanced malignant phenotypes in CC cells with overexpressed circHIPK3.

ATF6 aggravates angiogenesis-osteogenesis coupling during ankylosing spondylitis by mediating FGF2 expression in chondrocytes

SummaryAlthough angiogenesis-osteogenesis coupling is important in ankylosing spondylitis (AS), therapeutic agents targeting the vasculature remain elusive. Here, we identified activating transcription factor 6 (ATF6) as an important regulator of angiogenesis in AS patients. Firstly, we found that ATF6 and fibroblast growth factor 2 (FGF2) levels were higher in SKG mice and AS patient cartilage. The pro-angiogenic ability of human chondrocytes was enhanced through activated ATF6-FGF2 axis following long-term stimulation with inflammatory factors, e.g. TNF-α, IFN-γ or IL-17.Mechanistically, ATF6 interacted with the FGF2 promotor and promoted its transcription. Treatment with the ATF6 inhibitor Ceapin-A7 inhibited angiogenesis in vitro and angiogenesis-osteogenesis coupling in vivo. ATF6 may aggravate angiogenesis-osteogenesis coupling during AS by mediating FGF2 transcription in chondrocytes, implying that ATF6 represents a promising therapeutic target for AS.

Automated Indentation Demonstrates Structural Stiffness of Femoral Articular Cartilage and Temporomandibular Joint Mandibular Condylar Cartilage Is Altered in FgF2KO Mice

Objective Employ an automated indentation technique, using a commercially available machine, to assess the effect of fibroblast growth factor 2 (FGF2) expression on structural stiffness over the surface of both murine femoral articular cartilage (AC) and temporomandibular joint (TMJ) mandibular condylar cartilage (MCC). Design Experiments were performed using 3-month-old female homozygote Fgf2KO mice with wild type (WT) littermates. After euthanization, isolated mandibles and hindlimbs were either processed for histology or subjected to automated indentation on a Biomomentum Mach-1 v500csst with a 3-axis motion controller in a phosphate buffered saline bath using a 0.3 mm spherical tip indenter. The effect of indentation depth on normal force was characterized, then structural stiffness was calculated and mapped at multiple positions on the AC and MCC. Results Automated indentation of the AC and TMJ MCC was successfully completed and was able to demonstrate both regional variation in structural stiffness and differences between WT and Fgf2KO mice. Structural stiffness values for Fgf2KO AC were significantly smaller than WT at both the medial/anterior ( P < 0.05) and medial/posterior ( P < 0.05) positions. Global Fgf2KO also lead to a decrease in MCC thickness of the TMJ compared with WT ( P < 0.05) and increased structural stiffness values for Fgf2KO at both the posterior and anterior location ( P < 0.05). Conclusions Automated indentation spatially resolved differences in structural stiffness between WT and Fgf2KO tissue, demonstrating FGF2 expression affects femoral AC and TMJ MCC. This quantitative method will provide a valuable approach for functional characterization of cartilage tissues in murine models relevant to knee joint and TMJ health and disease.

Fibroblast Growth Factor-2 Prevents Synaptic Pathology in Minimal Hepatic Encephalopathy via NRG1/ErbB4 Signaling

Minimal hepatic encephalopathy (MHE) is implicated in the impairment of memory function. Fibroblast growth factor-2 (FGF2) is involved in modulating synaptic and neuronal formation. The aim of this study is to examined the impacts of FGF2 on MHE pathology. Our study addressed whether FGF2 could trigger neuregulin1 (NRG1) release to ameliorate synaptic impairment in MHE rats and in primary cultured neurons. The results showed the decreased FGF2 expression in MHE brains. After treatment with FGF2, secreted neuregulin1 (NRG1) and ErbB4 were increased, and the interaction of the 2 proteins was enhanced. Additionally, treatment with FGF2 or NRG1 induced synaptic formation, with increase in the activity of synapse and the density of dendritic spine, through Sirt1.NRG1 signaling was prevented by administration of FGF2, which acts through the FGFR1 in MHE rats. Intracerebroventricular injection with FGF2 or NRG1 mitigated the impairment of synaptogenesis. The data suggest that FGF2 may be a promising latent therapeutic reagent for MHE pathogenesis.

MiR-203 inhibits the proliferation, invasion, and migration of pancreatic cancer cells by down-regulating fibroblast growth factor 2

BackgroundAberrant fibroblast growth factor 2 (FGF2) expression is a major cause of poor prognosis in pancreatic cancer. MiR-203 is a newly discovered microRNA (miRNA) that can affect the biological behavior of tumors. This study investigated whether miR-203 can regulate FGF2 expression and its role in pancreatic cancer cell proliferation, apoptosis, invasion, and migration.MethodsMiR-203 expression in different cell lines was examined by qRT-PCR, followed by the establishment of knockdown and overexpression cell models. We used the CCK-8 assay to examine cell proliferation and the annexin V-APC/7-AAD double-staining method to detect apoptosis. In addition, we used wound healing and transwell assays to investigate the effects of miR-203 on the migration and invasion of pancreatic cancer cells. The effects of miR-203 knockdown and overexpression on FGF2 mRNA expression were detected by qRT-PCR. We also overexpressed FGF2 and examined the effects of FGF2 overexpression on the proliferation, apoptosis, invasion, and migration of pancreatic cancer cells. The binding of miR-203 to FGF2 was assessed by a luciferase reporter assay.ResultsWe found that the miR-203 expression level was significantly down-regulated in pancreatic cancer cells compared to normal pancreatic cells. Functionally, the knockdown of miR-203 inhibited cell proliferation and increased apoptosis. Equally important, miR-203 reduced the migration and invasion of pancreatic cancer cells. In addition, we found that miR-203 overexpression inhibited FGF2 expression in pancreatic cancer cells by qRT-PCR. FGF2 overexpression significantly affected the proliferation, invasion, and metastasis of pancreatic cancer cells. Mechanistically, miR-203 base-paired with the FGF2 mRNA, resulting in the knockdown of the FGF2 mRNA and the down-regulation of the FGF2 protein.ConclusionsMiR-203 inhibits FGF2 expression, regulates the proliferation of pancreatic cancer cells, and inhibits the invasion and metastasis of pancreatic cancer cells.