Beneficial Effects of Fibroblast Growth Factor-1 on Retinal Pigment Epithelial Cells Exposed to High Glucose-Induced Damage: Alleviation of Oxidative Stress, Endoplasmic Reticulum Stress, and Enhancement of Autophagy.

Diabetic retinopathy (DR) severely affects vision in individuals with diabetes. High glucose (HG) induces oxidative stress in retinal cells, a key contributor to DR development. Previous studies suggest that fibroblast growth factor-1 (FGF-1) can mitigate hyperglycemia and protect tissues from HG-induced damage. However, the specific effects and mechanisms of FGF-1 on DR remain unclear. In our study, FGF-1-pretreated adult retinal pigment epithelial (ARPE)-19 cells were employed to investigate. Results indicate that FGF-1 significantly attenuated HG-induced oxidative stress, including reactive oxygen species, DNA damage, protein carbonyl content, and lipid peroxidation. FGF-1 also modulated the expression of oxidative and antioxidative enzymes. Mechanistic investigations showed that HG induced high endoplasmic reticulum (ER) stress and upregulated specific proteins associated with apoptosis. FGF-1 effectively alleviated ER stress, reduced apoptosis, and restored autophagy through the adenosine monophosphate-activated protein kinase/mammalian target of the rapamycin signaling pathway. We observed that the changes induced by HG were dose-dependently reversed by FGF-1. Higher concentrations of FGF-1 (5 and 10 ng/mL) exhibited increased effectiveness in mitigating HG-induced damage, reaching statistical significance (p < 0.05). In conclusion, our study underscores the promising potential of FGF-1 as a safeguard against DR. FGF-1 emerges as a formidable intervention, attenuating oxidative stress, ER stress, and apoptosis, while concurrently promoting autophagy. This multifaceted impact positions FGF-1 as a compelling candidate for alleviating retinal cell damage in the complex pathogenesis of DR.

The optimized priming effect of FGF-1 and FGF-2 enhances preadipocyte lineage commitment in human adipose-derived mesenchymal stem cells.

The cell-assisted lipotransfer technique, integrating adipose-derived mesenchymal stem cells (ADMSCs), has transformed lipofilling, enhancing fat graft viability. However, the multipotent nature of ADMSCs poses challenges. To improve safety and graft vitality and to reduce unwanted lineage differentiation, this study refines the methodology by priming ADMSCs into preadipocytes-unipotent, self-renewing cells. We explored the impact of fibroblast growth factor-1 (FGF-1), fibroblast growth factor-2 (FGF-2), and epidermal growth factor (EGF), either alone or in combination, on primary human ADMSCs during the proliferative phase. FGF-2 emerged as a robust stimulator of cell proliferation, preserving stemness markers, especially when combined with EGF. Conversely, FGF-1, while not significantly affecting cell growth, influenced cell morphology, transitioning cells to a rounded shape with reduced CD34 expression. Furthermore, co-priming with FGF-1 and FGF-2 enhanced adipogenic potential, limiting osteogenic and chondrogenic tendencies, and possibly promoting preadipocyte commitment. These preadipocytes exhibited unique features: rounded morphology, reduced CD34, decreased preadipocyte factor 1 (Pref-1), and elevated C/EBPα and PPARγ, alongside sustained stemness markers (CD73, CD90, CD105). Mechanistically, FGF-1 and FGF-2 activated key adipogenic transcription factors-C/EBPα and PPARγ-while inhibiting GATA3 and Notch3, which are adipogenesis inhibitors. These findings hold the potential to advance innovative strategies for ADMSC-mediated lipofilling procedures.

Significant Enhancement of Fibroblast Migration, Invasion, and Proliferation by Exosomes Loaded with Human Fibroblast Growth Factor 1.

Exosomes possess several inherent properties that make them ideal for biomedical applications, including robust stability, biocompatibility, minimal immunogenicity, and the ability to cross biological barriers. These natural nanoparticles have recently been developed as drug delivery vesicles. To do so, therapeutic molecules must be efficiently loaded into exosomes first. Very recently, we developed a cell-penetrating peptide (CPP)-based platform for loading of nucleic acids and small molecules into exosomes by taking advantage of the membrane-penetration power of CPPs. Here, we extended this simple but effective platform by loading a protein cargo into exosomes isolated from either mesenchymal stem cells from three different sources or two different cancer cell lines. The protein cargo is a fusion protein YARA-FGF1-GFP through the covalent conjugation of a model CPP called YARA to human fibroblast growth factor 1 (FGF1) and green fluorescence protein (GFP). Loading of YARA-FGF1-GFP into exosomes was time-dependent and reached a maximum of about 1600 YARA-FGF1-GFP molecules in each exosome after 16 h. The ladened exosomes were effectively internalized by mammalian cells, and subsequently, the loaded protein cargo YARA-FGF1-GFP was delivered intracellularly. In comparison to YARA, YARA-FGF1-GFP, the unloaded exosomes, and the exosomes loaded with YARA, the exosomes loaded with YARA-FGF1-GFP substantially promoted the migration, proliferation, and invasion capabilities of mouse and human fibroblasts, which are important factors for wound repair. The work extended our CPP-based exosomal cargo loading platform and established a foundation for developing novel wound-healing therapies using exosomes loaded with FGF1 and other growth factors.

Recombinant bovine FGF1 promotes muscle satellite cells mitochondrial fission and proliferation in serum-free conditions.

Cell cultured meat is a novel and promising technology, but developing specific culture medium for muscle cells remains one of the main technical obstacles. FGF1 signaling is reported to promote proliferation and maintain proliferative capacity of satellite cells. However, the effect of FGF1 as a supplement to serum-free medium on satellite cells in vitro culture is still unclear. In this study, an efficient method for the production of soluble and biologically active recombinant bovine FGF1 (rbFGF1) protein in Escherichia coli was established. The soluble expression level of TrxA-rbFGF1 fusion protein was 562 mg/L in shake flasks, resulting in 5.5 mg of pure rbFGF1 from 0.1 L of starting culture. In serum-free culture conditions, rbFGF1 effectively promoted the proliferation and regulated the mitochondrial morphology and function of C2C12 myoblasts.rbFGF1 activated extracellular signal-regulated kinases1/2 (ERK1/2) signaling in C2C12 myoblasts, which further stimulated dynamin related protein 1 (DRP1) Ser616 phosphorylation. These findings highlighted the potential application of rbFGF1 in developing effective serum-free medium for cultured meat production.

Intracellular FGF1 protects cells from apoptosis through direct interaction with p53.

Fibroblast growth factor 1 (FGF1) acts by activating specific tyrosine kinase receptors on the cell surface. In addition to this classical mode of action, FGF1 also exhibits intracellular activity. Recently, we found that FGF1 translocated into the cell interior exhibits anti-apoptotic activity independent of receptor activation and downstream signaling. Here, we show that expression of FGF1 increases the survival of cells treated with various apoptosis inducers, but only when wild-type p53 is present. The p53-negative cells were not protected by either ectopically expressed or translocated FGF1. We also confirmed the requirement of p53 for the anti-apoptotic intracellular activity of FGF1 by silencing p53, resulting in loss of the protective effect of FGF1. In contrast, in p53-negative cells, intracellular FGF1 regained its anti-apoptotic properties after transfection with wild-type p53. We also found that FGF1 directly interacts with p53 in cells and that the binding region is located in the DBD domain of p53. We therefore postulate that intracellular FGF1 protects cells from apoptosis by directly interacting with p53.

FGF1 reduces cartilage injury in osteoarthritis via regulating AMPK/Nrf2 pathway.

Osteoarthritis (OA) is a systemic joint degenerative disease involving a variety of cytokines and growth factors. In this study, we investigated the protective effect of fibroblast growth factor 1 (FGF1) knockdown on OA and its underlying mechanisms in vitro. In addition, we evaluated the effect of FGF1 knockout on the destabilization of the medial meniscus (DMM) and examined the anterior and posterior cruciate ligament model in vivo. FGF1 affects OA cartilage destruction by increasing the protein expression of Nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1), which is associated with the phosphorylation of AMPK and its substrates. Our study showed that FGF1 knockdown could reverse the oxidative damage associated with osteoarthritis. Nrf2 knockdown eliminated the antioxidant effect of FGF1 knockdown on chondrocytes. Furthermore, AMPK knockdown could stop the impact of FGF1 knockdown on osteoarthritis. These findings suggested that FGF1 knockdown could effectively prevent and reverse osteoarthritis by activating AMPK and Nrf2 in articular chondrocytes.

Protection against Metabolic Associated Fatty Liver Disease by Protocatechuic Acid.

Gut microbiota-diet interaction has been identified as a key factor of metabolic associated fatty liver disease (MAFLD). Recent studies suggested that dietary polyphenols may protect against MAFLD by regulating gut microbiota; however, the underlying mechanisms remain elusive. We first investigated the effects of cyanidin 3-glucoside and its phenolic metabolites on high-fat diet induced MAFLD in C57BL/6J mice, and protocatechuic acid (PCA) showed a significant positive effect. Next, regulation of PCA on lipid metabolism and gut microbiota were explored by MAFLD mouse model and fecal microbiota transplantation (FMT) experiment. Dietary PCA reduced intraperitoneal and hepatic fat deposition with lower levels of transaminases (AST & ALT) and inflammatory cytokines (IL-1ß, IL-2, IL-6, TNF-α & MCP-1), but higher HDL-c/LDL-c ratio. Characterization of gut microbiota indicated that PCA decreased the Firmicutes/Bacteroidetes ratio mainly by reducing the relative abundance of genus Enterococcus, which was positively correlated with the levels of LDL-c, AST, ALT and most of the up-regulated hepatic lipids by lipidomics analysis. FMT experiments showed that Enterococcus faecalis caused hepatic inflammation, fat deposition and insulin resistance with decreased expression of carnitine palmitoyltransferase-1 alpha (CPT1α), which can be reversed by PCA through inhibiting Enterococcus faecalis. Transcriptomics analysis suggested that Enterococcus faecalis caused a significant decrease in the expression of fibroblast growth factor 1 (Fgf1), and PCA recovered the expression of Fgf1 with insulin-like growth factor binding protein 2 (Igfbp2), insulin receptor substrate 1 (Irs1) and insulin receptor substrate 2 (Irs2). These results demonstrated that high proportion of gut Enterococcus faecalis accelerates MAFLD with decreased expression of CPT1α and Fgf1, which can be prevented by dietary supplementation of PCA.

Effect of recombinant human acidic fibroblast growth factor on nasal mucosal healing after endoscopic sinus surgery.

BACKGROUND: Postoperative nasal treatment is an important factor affecting the outcomes of endoscopic sinus surgery (ESS) in patients with chronic rhinosinusitis (CRS). This study aimed to determine the effect of recombinant human acidic fibroblast growth factor (rh-aFGF) on nasal mucosal healing after ESS. METHODS: This study is a prospective, single-blind, and randomized controlled clinical study. Fifty-eight CRS patients with nasal polyps (CRSwNP) with bilateral ESS were enrolled and randomly given 1 mL of budesonide nasal spray and 2 mL of rh-aFGF solution (rh-aFGF group) or 1 mL of budesonide nasal spray and 2 mL of rh-aFGF solvent (budesonide group)-infiltrated Nasopore nasal packing after ESS. Preoperative and postoperative scores for Sino-Nasal Outcome Test (SNOT-22), Visual Analogue Scale (VAS), and Lund-Kennedy were collected and analyzed. RESULTS: Forty-two patients completed the 12-week follow-up. Postoperative SNOT-22 scores and VAS scores showed no significant differences between the two groups. In terms of the Lund-Kennedy scores, there was a statistically significant difference between the two groups at the 2-, 4-, 8-, and 12-week postoperative visits, but not at the 1-week visit. Twelve weeks after surgery, the nasal mucosa had completely epithelialized in 18 patients in the rh-aFGF group and in 12 patients in the budesonide group (χ2 = 4.200, P = 0.040). CONCLUSION: The combined application of rh-aFGF and budesonide significantly improved postoperative endoscopic appearance in the nasal mucosal healing process.

FGF1 ameliorates obesity-associated hepatic steatosis by reversing IGFBP2 hypermethylation.

Obesity is a major contributing factor for metabolic-associated fatty liver disease (MAFLD). Fibroblast growth factor (FGF) 1 is the first paracrine FGF family member identified to exhibit promising metabolic regulatory properties capable of conferring glucose-lowering and insulin-sensitizing effect. This study explores the role and molecular underpinnings of FGF1 in obesity-associated hepatic steatosis. In a mouse high-fat diet (HFD)-induced MAFLD model, chronic treatment with recombinant FGF1(rFGF1) was found to effectively reduce the severity of insulin resistance, hyperlipidemia, and inflammation. FGF1 treatment decreased lipid accumulation in the mouse liver and palmitic acid-treated AML12 cells. These effects were associated with decreased mature form SREBF1 expression and its target genes FASN and SCD1. Interestingly, we uncovered that rFGF1 significantly induced IGFBP2 expression at both mRNA and protein levels in HFD-fed mouse livers and cultured hepatocytes treated with palmitic acid. Adeno-associated virus-mediated IGFBP2 suppression significantly diminished the therapeutic benefit of rFGF1 on MAFLD-associated phenotypes, indicating that IGFBP2 plays a crucial role in the FGF1-mediated reduction of hepatic steatosis. Further analysis revealed that rFGF1 treatment reduces the recruitment of DNA methyltransferase 3 alpha to the IGFBP2 genomic locus, leading to decreased IGFBP2 gene methylation and increased mRNA and protein expression. Collectively, our findings reveal FGF1 modulation of lipid metabolism via epigenetic regulation of IGFBP2 expression, and unravel the therapeutic potential of the FGF1-IGFBP2 axis in metabolic diseases associated with obesity.

Novel Muscle-Homing Peptide FGF1 Conjugate Based on AlphaFold for Type 2 Diabetes Mellitus.

Drugs for metabolic diseases usually require systemic administration and act on multiple tissues, which may produce some unpredictable side effects. There have been many successful studies on targeted drugs, especially antitumor drugs. However, there is still little research on metabolic disease drugs targeting specific tissues. Fibroblast growth factor 1 (FGF1) is a potential therapy for type 2 diabetes (T2D) without the risk of hypoglycemia. However, the major impediment to the clinical application of FGF1 is its mitogenic potential. We previously engineered an FGF1 variant (named FGF1ΔHBS) to tune down its mitogenic activity via reducing the heparin-binding ability. However, other notable side effects still remained, including severe appetite inhibition, pathogenic loss of body weight, and increase in fatality rate. In this study, we used AlphaFold2 and PyMOL visualization tools to construct a novel FGF1ΔHBS conjugate fused with skeletal muscle-targeted (MT) peptide through a flexible peptide linker termed MT-FGF1ΔHBS. We found that MT-FGF1ΔHBS specifically homed to skeletal muscle tissue after systemic administration and induced a potent glucose-lowering effect in T2D mice without hypoglycemia. Mechanistically, MT-FGF1ΔHBS elicits the glucose-lowering effect via AMPK activation to promote the GLUT4 expression and translocation in skeletal muscle cells. Notably, compared with native FGF1ΔHBS, MT-FGF1ΔHBS had minimal effects on food intake and body weight and did not induce any hyperplasia in major tissues of both T2D and normal mice, indicating that this muscle-homing protein may be a promising candidate for T2D treatment. Our targeted peptide strategy based on computer-aided structure prediction in this study could be effectively applied for delivering agents to functional tissues to treat metabolic or other diseases, offering enhanced efficacy and reducing systemic off-target side effects.

Polyphenol-driven facile assembly of a nanosized acid fibroblast growth factor-containing coacervate accelerates the healing of diabetic wounds.

Diabetic wounds are challenging to heal due to complex pathogenic abnormalities. Routine treatment with acid fibroblast growth factor (aFGF) is widely used for diabetic wounds but hardly offers a satisfying outcome due to its instability. Despite the emergence of various nanoparticle-based protein delivery approaches, it remains challenging to engineer a versatile delivery system capable of enhancing protein stability without the need for complex preparation. Herein, a polyphenol-driven facile assembly of nanosized coacervates (AE-NPs) composed of aFGF and Epigallocatechin-3-gallate (EGCG) was constructed and applied in the healing of diabetic wounds. First, the binding patterns of EGCG and aFGF were predicted by molecular docking analysis. Then, the characterizations demonstrated that AE-NPs displayed higher stability in hostile conditions than free aFGF by enhancing the binding activity of aFGF to cell surface receptors. Meanwhile, the AE-NPs also had a powerful ability to scavenge reactive oxygen species (ROS) and promote angiogenesis, which significantly accelerated full-thickness excisional wound healing in diabetic mice. Besides, the AE-NPs suppressed the early scar formation by improving collagen remodeling and the mechanism was associated with the TGF-ß/Smad signaling pathway. Conclusively, AE-NPs might be a potential and facile strategy for stabilizing protein drugs and achieving the scar-free healing of diabetic wounds. STATEMENT OF SIGNIFICANCE: Diabetic chronic wound is among the serious complications of diabetes that eventually cause the amputation of limbs. Herein, a polyphenol-driven facile assembly of nanosized coacervates (AE-NPs) composed of aFGF and EGCG was constructed. The EGCG not only acted as a carrier but also possessed a therapeutic effect of ROS scavenging. The AE-NPs enhanced the binding activity of aFGF to cell surface receptors on the cell surface, which improved the stability of aFGF in hostile conditions. Moreover, AE-NPs significantly accelerated wound healing and improved collagen remodeling by regulating the TGF-ß/Smad signaling pathway. Our results bring new insights into the field of polyphenol-containing nanoparticles, showing their potential as drug delivery systems of macromolecules to treat diabetic wounds.

Beneficial Effects of Oleosomes Fused with Human Fibroblast Growth Factor 1 on Wound Healing via the Promotion of Angiogenesis.

In our previous study, human fibroblast growth factor 1 was successfully fused with oleosomes, energy-storing organelles of seeds, which are considered to be excellent "expression carriers" for substances with a convenient purification process. The present work aimed to explore the beneficial effects of oleosomes fused with human fibroblast growth factor 1 (OLAF) on wound healing. The data showed marked improvements in terms of the angiogenesis, vascular integrity, collagen and inflammation on the wound sites of rats with a full-thickness skin defect. Moreover, the positive role of OLAF in promoting angiogenesis and its possible pathways were clarified in vivo and in vitro. The results showed that the number, length and branches of the blood vessels of the chick embryo chorioallantoic membrane were markedly increased after OLAF treatment. Meanwhile, the in vitro results also revealed that 100 ng/mL OLAF exhibited a promoting effect on the proliferation, migration and tube formation of human umbilical vein endothelial cells. In addition, the potential of OLAF to improve wound angiogenesis was demonstrated to be associated with an up-regulated PI3K/Akt pathway by transcriptome sequencing analysis and the introduction of a PI3K/Akt pathway inhibitor (LY294002). These findings suggest that OLAF has many prospects in the development of drugs for wound healing.

Resveratrol and FGF1 Synergistically Ameliorates Doxorubicin-Induced Cardiotoxicity via Activation of SIRT1-NRF2 Pathway.

Doxorubicin (DOX) has received attention due to dose-dependent cardiotoxicity through abnormal redox cycling. Native fibroblast growth factor 1 (FGF1) is known for its anti-oxidative benefits in cardiovascular diseases, but possesses a potential tumorigenic risk. Coincidentally, the anti-proliferative properties of resveratrol (RES) have attracted attention as alternatives or auxiliary therapy when combined with other chemotherapeutic drugs. Therefore, the purpose of this study is to explore the therapeutic potential and underlying mechanisms of co-treatment of RES and FGF1 in a DOX-treated model. Here, various cancer cells were applied to determine whether RES could antagonize the oncogenesis effect of FGF1. In addition, C57BL/6J mice and H9c2 cells were used to testify the therapeutic potential of a co-treatment of RES and FGF1 against DOX-induced cardiotoxicity. We found RES could reduce the growth-promoting activity of FGF1. Additionally, the co-treatment of RES and FGF1 exhibits a more powerful cardio-antioxidative capacity in a DOX-treated model. The inhibition of SIRT1/NRF2 abolished RES in combination with FGF1 on cardioprotective action. Further mechanism analysis demonstrated that SIRT1 and NRF2 might form a positive feedback loop to perform the protective effect on DOX-induced cardiotoxicity. These favorable anti-oxidative activities and reduced proliferative properties of the co-treatment of RES and FGF1 provided a promising therapy for anthracycline cardiotoxicity during chemotherapy.

∆nFGF1 Protects ß-Cells against High Glucose-Induced Apoptosis via the AMPK/SIRT1/PGC-1α Axis.

Long-term exposure to high glucose leads to ß-cell dysfunction and death. Fibroblast growth factor 1 (FGF1) has emerged as a promising diabetes treatment, but its pharmaceutical role and mechanism against glucolipotoxicity-induced ß-cell dysfunction remain uncharacterized. Wild-type FGF1 (FGF1WT) may exhibit in vivo mitogenicity, but deletion of N-terminal residues 1-27 gives a nonmitogenic variant, ∆nFGF1, that does not promote cell proliferation and still retains the metabolic activity of FGF1WT. To investigate the roles of ∆nFGF1 on glucose regulation and potential islet ß-cell dysfunction, db/db mice were used as a model of type 2 diabetes. The results showed that insulin secretion and apoptosis of islet ß-cells were dramatically improved in ∆nFGF1-treated db/db mice. To further test the effects of ∆nFGF1 treatment, pancreatic ß-cell (MIN6) cells were exposed to a mixture of palmitic acid (PA) and high glucose (HG) to mimic glucolipotoxic conditions in vitro. Treatment with ∆nFGF1 significantly inhibited glucolipotoxicity-induced apoptosis. Mechanistically, ∆nFGF1 exerts a protective effect on ß-cells via activation of the AMPK/SIRT1/PGC-1α signaling pathway. These findings demonstrate that ∆nFGF1 protects pancreatic ß-cells against glucolipotoxicity-induced dysfunction and apoptosis.

Sustained inhibition of NPY/AgRP neuronal activity by FGF1.

In rodent models of type 2 diabetes (T2D), central administration of FGF1 normalizes elevated blood glucose levels in a manner that is sustained for weeks or months. Increased activity of NPY/AgRP neurons in the hypothalamic arcuate nucleus (ARC) is implicated in the pathogenesis of hyperglycemia in these animals, and the ARC is a key brain area for the antidiabetic action of FGF1. We therefore sought to determine whether FGF1 inhibits NPY/AgRP neurons and, if so, whether this inhibitory effect is sufficiently durable to offer a feasible explanation for sustained diabetes remission induced by central administration of FGF1. Here, we show that FGF1 inhibited ARC NPY/AgRP neuron activity, both after intracerebroventricular injection in vivo and when applied ex vivo in a slice preparation; we also showed that the underlying mechanism involved increased input from presynaptic GABAergic neurons. Following central administration, the inhibitory effect of FGF1 on NPY/AgRP neurons was also highly durable, lasting for at least 2 weeks. To our knowledge, no precedent for such a prolonged inhibitory effect exists. Future studies are warranted to determine whether NPY/AgRP neuron inhibition contributes to the sustained antidiabetic action elicited by intracerebroventricular FGF1 injection in rodent models of T2D.

Ectoderm-derived frontal bone mesenchymal stem cells promote traumatic brain injury recovery by alleviating neuroinflammation and glutamate excitotoxicity partially via FGF1.

BACKGROUND: Traumatic brain injury (TBI) leads to cell and tissue impairment, as well as functional deficits. Stem cells promote structural and functional recovery and thus are considered as a promising therapy for various nerve injuries. Here, we aimed to investigate the role of ectoderm-derived frontal bone mesenchymal stem cells (FbMSCs) in promoting cerebral repair and functional recovery in a murine TBI model. METHODS: A murine TBI model was established by injuring C57BL/6 N mice with moderate-controlled cortical impact to evaluate the extent of brain damage and behavioral deficits. Ectoderm-derived FbMSCs were isolated from the frontal bone and their characteristics were assessed using multiple differentiation assays, flow cytometry and microarray analysis. Brain repairment and functional recovery were analyzed at different days post-injury with or without FbMSC application. Behavioral tests were performed to assess learning and memory improvements. RNA sequencing analysis, immunofluorescence staining, and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) were used to examine inflammation reaction and neural regeneration. In vitro co-culture analysis and quantification of glutamate transportation were carried out to explore the possible mechanism of neurogenesis and functional recovery promoted by FbMSCs. RESULTS: Ectoderm-derived FbMSCs showed fibroblast like morphology and osteogenic differentiation capacity. FbMSCs were CD105, CD29 positive and CD45, CD31 negative. Different from mesoderm-derived MSCs, FbMSCs expressed the ectoderm-specific transcription factor Tfap2ß. TBI mice showed impaired learning and memory deficits. Microglia and astrocyte activation, as well as neural damage, were significantly increased post-injury. FbMSC application ameliorated the behavioral deficits of TBI mice and promoted neural regeneration. RNA sequencing analysis showed that signal pathways related to inflammation decreased, whereas those related to neural activation increased. Immunofluorescence staining and qRT-PCR data revealed that microglial activation and astrocyte polarization to the A1 phenotype were suppressed by FbMSC application. In addition, FGF1 secreted from FbMSCs enhanced glutamate transportation by astrocytes and alleviated the cytotoxic effect of excessive glutamate on neurons. CONCLUSIONS: Ectoderm-derived FbMSC application significantly alleviated neuroinflammation, brain injury, and excitatory toxicity to neurons, improved cognition and behavioral deficits in TBI mice. Therefore, ectoderm-derived FbMSCs could be ideal therapeutic candidates for TBI which mostly affect cells from the same embryonic origins as FbMSCs.

FGF1 alleviates LPS-induced acute lung injury via suppression of inflammation and oxidative stress.

BACKGROUND: Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), are devastating clinical disorders with high mortality, and for which more effective therapies are urgently needed. FGF1, the prototype member of the FGF family, is shown to exert protective effects against injurious stimuli in multiple disease models. Here we aimed to evaluate whether FGF1 pretreatment is protective against LPS-induced ALI and elucidate the potential underlying mechanisms. METHODS: For drug-treated groups, C57B/6 mice received a single i.p. injection of FGF1 (1 mg/kg) 1 h before the LPS challenge or not. To induce the ALI model, the mice were treated by intratracheal instillation of LPS (5 mg/kg). Then, histopathological changes in lung tissues were assessed by hematoxylin and eosin staining and transmission electron microscopy. ELISA and qPCR assays were used to detect pro-inflammatory cytokine levels in BALF and lung tissues, respectively. The total number of inflammatory cells (neutrophils and macrophages) in BALF were counted using the Wright-Giemsa method. The expressions of reactive oxygen species (ROS) and malondialdehyde (MDA) were measured using their respective kits. Western blot and immunostaining were used to evaluate the expressions of antioxidants (Nrf-2, HO-1, SOD2, GPX4, and Catalase), as well as the inflammatory and/or apoptosis-related factors (TLR4, NF-κB, and Cleaved- caspase 3). RESULTS: FGF1 pretreatment significantly ameliorated the LPS-induced histopathological changes, reduced lung wet/dry ratios, ROS and MDA levels, total BALF protein, inflammatory cell infiltration, proinflammatory cytokine levels, and significantly increased the expression of antioxidant proteins (Nrf-2, HO-1, Catalase, and SOD2). In addition, FGF1 pretreatment significantly reduced the expression of TLR4 and cleaved- caspase 3, inhibited NF-κB activation, and reduced LPS-induced cell apoptosis. CONCLUSIONS: Altogether, our results suggest that FGF1 pretreatment is protective against LPS-induced ALI through mediating anti-inflammatory and antioxidant effects, which may be attributed to the downregulation of TLR4 expression and inhibition of NF-κB activation, as well as promotion of antioxidant defenses. Therefore, FGF1 administration may prove beneficial in preventative strategies for ALI/ARDS.

Non-mitogenic fibroblast growth factor 1 protects against ischemic stroke by regulating microglia/macrophage polarization through Nrf2 and NF-κB pathways.

Microglia are immune cells in the central nervous system (CNS) that participate in response to pathological process after ischemic injury. Non-mitogenic fibroblast growth factor 1 (nmFGF1) is an effective neuroprotective factor that is also known as a metabolic regulator. The present study aimed to investigate the effects and mechanism of the neuroprotective ability of nmFGF1 on microglia in mice after photothrombosis (PT) stroke model, to determine whether it could ameliorate ischemic injury in stroke experiment. We discovered that the intranasal administration of nmFGF1 reduced infarct size and ameliorated neurological deficits in behavioral assessment by regulating the secretion of proinflammatory and anti-inflammatory cytokines. Furthermore, in the in vitro experiments, we found that nmFGF1 regulated the expression levels of proinflammatory and anti-inflammatory cytokines in oxygen-glucose deprivation (OGD) and lipopolysaccharide (LPS) stimulation. Evidence have shown that when nuclear factor erythroid 2-related factor 2 (Nfr2) is activated, it inhibits nuclear factor-kappa B (NF-κB) activation to alleviate inflammation. Interestingly, nmFGF1 treatment in vivo remarkably inhibited NF-κB pathway activation and activated Nrf2 pathway. In addition, nmFGF1 and NF-κB inhibitor (BAY11-7082) inhibited NF-κB pathway in LPS-stimulated BV2 microglia. Moreover, in LPS-stimulated BV2 microglia, the anti-inflammatory effect produced by nmFGF1 was knocked down by Nrf2 siRNA. These results indicate that nmFGF1 promoted functional recovery in experimental stroke by modulating microglia/macrophage-mediated neuroinflammation via Nrf2 and NF-κB signaling pathways, making nmFGF1 a potential agent against ischemic stroke.

Combined micro-osmotic pump infusion and intracerebroventricular injection to study FGF1 signaling pathways in the mouse brain.

Intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1) elicits remission of diabetic hyperglycemia in rodent models of type 2 diabetes. Here, we present an optimized protocol to study the intracellular signaling pathways underlying the FGF1-induced sustained glucose lowering in the mouse brain. This protocol combines icv injection of FGF1 and osmotic mini-pump infusion of U0126, an inhibitor of MAPK/ERK signaling. We describe the surgical procedure and verification of U0126 inhibition of FGF1-stimulated hypothalamic MAPK/ERK signaling via western blot. For complete details on the use and execution of this protocol, please refer to Brown et al. (2021).

A new FGF1 variant protects against adriamycin-induced cardiotoxicity via modulating p53 activity.

A cumulative and progressively developing cardiomyopathy induced by adriamycin (ADR)-based chemotherapy is a major obstacle for its clinical application. However, there is a lack of safe and effective method to protect against ADR-induced cardiotoxicity. Here, we found that mRNA and protein levels of FGF1 were decreased in ADR-treated mice, primary cardiomyocytes and H9c2 cells, suggesting the potential effect of FGF1 to protect against ADR-induced cardiotoxicity. Then, we showed that treatment with a FGF1 variant (FGF1ΔHBS) with reduced proliferative potency significantly prevented ADR-induced cardiac dysfunction as well as ADR-associated cardiac inflammation, fibrosis, and hypertrophy. The mechanistic study revealed that apoptosis and oxidative stress, the two vital pathological factors in ADR-induced cardiotoxicity, were largely alleviated by FGF1ΔHBS treatment. Furthermore, the inhibitory effects of FGF1ΔHBS on ADR-induced apoptosis and oxidative stress were regulated by decreasing p53 activity through upregulation of Sirt1-mediated p53 deacetylation and enhancement of murine double minute 2 (MDM2)-mediated p53 ubiquitination. Upregulation of p53 expression or cardiac specific-Sirt1 knockout (Sirt1-CKO) almost completely abolished FGF1ΔHBS-induced protective effects in cardiomyocytes. Based on these findings, we suggest that FGF1ΔHBS may be a potential therapeutic agent against ADR-induced cardiotoxicity.