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Growth differentiation factor 11 (GDF11), a member of the transforming growth factor β superfamily, is widely expressed in multiple species such as human, mouse, rat, horse and sheep. Moreover, GDF11 is implicated in diverse biological functions and plays an important role in regulating anterior/posterior patterning, skeletal muscle regeneration, bone formation, vascular remodeling and neurogenesis. Recent studies have revealed that GDF11 in blood reverses age-related cardiac hypertrophy, skeletal muscle dysfunction and age-related cognitive decline, suggesting the potential value of GDF11 on anti-ageing. However, some other studies questioned the effects of GDF11 on anti-ageing. Herein, we highlighted structural characteristics of GDF11, advances in effects of GDF11 on anti-ageing, and the controversies of GDF11, to provide new insights for future studies on anti-ageing.
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Objective To study the effect of growth differentiation factor (GDF) 11-silenced bone marrow stromal cells (BMSCs) on bone regeneration in early steroid-induced osteonecrosis of the femoral head in rats.Methods After GDF11 expression in BMSCs was inhibited by siRNA,the knockdown efficiency and transfection cytotoxicity were detected.The further experiments both in vitro (n =3) and in vivo (n =8)were divided into 4 groups respectively:blank control group (without any intervention),model group (glucocorticoid treatment),experimental group (siRNA transfection and glucocorticoid treatment) and negative control group (negative control transfection and glucocorticoid treatment).The BMSCs were induced into osteogenic differentiation.Alkaline phosphatase (ALP) staining and alizarin red staining were applied to evaluate the osteogenic differentiation ability of the cells while reverse transcription polymerase chain reaction (qRT-PCR) was employed to detect the relative expression levels of osteogenic markers.The osteogenesis in the necrotic femoral head was evaluated by microCT,H& E staining,immunohistochemistry staining and biomechanical test.Results No transfection cytotoxicity was found (P ＞ 0.05).The ALP staining and alizarin red staining showed that the osteogenic differentiation of BMSCs in the experimental group was better than that in the model group.At the level of mRNA,the relative expression of ALP,runt-related transcription factor (Runx) 2,osteocalcin (OCN) and type Ⅰ collagen (α1) (COL1A1) in the blank control group (1.00 ± 0.09,1.02 ± 0.23,1.03 ± 0.30 and 1.02 ± 0.25,respectively) were significantly higher than those in the model group (0.46±0.11,0.50±0.11,0.35±0.01 and0.57±0.02,respectively) but significantly lower than those in the experimental group (1.97±0.30,0.94±0.19,1.50±0.18 and 1.28 ±0.37) (all P ＜ 0.05).MicroCT images and quantitative analysis showed that the bone mass in the experimental group was significantly increased compared with the model group (P ＜ 0.05).Histological examination showed better bone regeneration and higher expression of Runx2 and COL1 in the necrotic femoral head in the experimental group than in the model group.Improved biomechanical properties were shown in the experimental group compared with the model group (P ＜ 0.05).Conclusions Silence of GDF11 expression may alleviate the inhibitory effect of glucocorticoid on osteogenic differentiation of BMSCs.Early transplantation of GDF11-silenced BMSCs may promote osteogenesis in the necrotic femoral head in rats.
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Objective@#To study the effect of growth differentiation factor (GDF) 11-silenced bone marrow stromal cells (BMSCs) on bone regeneration in early steroid-induced osteonecrosis of the femoral head in rats.@*Methods@#After GDF11 expression in BMSCs was inhibited by siRNA, the knockdown efficiency and transfection cytotoxicity were detected. The further experiments both in vitro (n=3) and in vivo (n=8) were divided into 4 groups respectively: blank control group (without any intervention), model group (glucocorticoid treatment), experimental group (siRNA transfection and glucocorticoid treatment) and negative control group (negative control transfection and glucocorticoid treatment). The BMSCs were induced into osteogenic differentiation. Alkaline phosphatase (ALP) staining and alizarin red staining were applied to evaluate the osteogenic differentiation ability of the cells while reverse transcription polymerase chain reaction (qRT-PCR) was employed to detect the relative expression levels of osteogenic markers. The osteogenesis in the necrotic femoral head was evaluated by microCT, H&E staining, immunohistochemistry staining and biomechanical test.@*Results@#No transfection cytotoxicity was found (P>0.05). The ALP staining and alizarin red staining showed that the osteogenic differentiation of BMSCs in the experimental group was better than that in the model group. At the level of mRNA, the relative expression of ALP, runt-related transcription factor (Runx) 2, osteocalcin (OCN) and type Ⅰ collagen (α1) (COL1A1) in the blank control group (1.00±0.09, 1.02±0.23, 1.03±0.30 and 1.02±0.25, respectively) were significantly higher than those in the model group (0.46±0.11, 0.50±0.11, 0.35±0.01 and 0.57±0.02, respectively) but significantly lower than those in the experimental group (1.97±0.30, 0.94±0.19, 1.50±0.18 and 1.28±0.37) (all P<0.05). MicroCT images and quantitative analysis showed that the bone mass in the experimental group was significantly increased compared with the model group (P<0.05). Histological examination showed better bone regeneration and higher expression of Runx2 and COL1 in the necrotic femoral head in the experimental group than in the model group. Improved biomechanical properties were shown in the experimental group compared with the model group (P<0.05).@*Conclusions@#Silence of GDF11 expression may alleviate the inhibitory effect of glucocorticoid on osteogenic differentiation of BMSCs. Early transplantation of GDF11-silenced BMSCs may promote osteogenesis in the necrotic femoral head in rats.
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Objective To investigate the effects of growth differentiation factor 11 ( GDF11 ) on β-cell function in db/db mice and its possible mechanism. Methods Twenty eight-week-old male db/db mice were randomizedtoi.p. administration of GDF11(0.3mg·kg-1·day-1)or equivalent PBS(n=10)for 6 weeks.10age-matched male db/m were used as normal control, received equivalent PBS injection for 6 weeks. Blood glucose levels, body weights and food intake were monitored weekly. IPGTT and glucose-stimulated insulin secretion ( GSIS) were analyzed. After 6 weeks of intervention, serum HbA1C , TG, TC, and FFA were measured respectively. The concentrations of hormones in serum and pancreas were evaluated. The mRNA expression of Pdx-1, MafA, Nkx6. 1, and insulin2 were determined by RT-PCR. The expression of phosphorylated Smd2 (P-Smad2), Smad2 in islet were examined by western blot. Results Compared with NC group, GDF11 administration decreased FBG, HbA1C , modified lipid profiles. GDF11 improved glucose tolerance and augmented GSIS. Moreover, GDF11 increased serum insulin and pancreatic insulin content, while decreased serum glucagon concentration. The expression of Pdx-1, MafA, Nkx6. 1, and Insulin2 were significantly increased in GDF11 group. GDF11 elevated the expression of P-Smad2 in islets. Conclusion s GDF11 may preserve β-cell function and facilitate the secretion and production of insulin. Diminishing the metabolic abnormalities, alleviating the secretion of glucagon, as well as maintaining the key transcript factor activation may contribute to the amelioration of β-cell function after GDF11 administration. Smad2 pathway may be related to the protective effects of GDF11.
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Objective To investigate the effects of growth differentiation factor 11 (GDF11) on proliferation of mouse neural stem cells (NSCs) and expression levels of transforming growth factor (TGF)-β/Smads and Wnt/β-Catenin signal key proteins.Methods NSCs,derived from the subventricular zone of E14 d CD1 mice,were cultured and induced differentiation;specific proteins nestin and SOX2 were confirmed by immunofluorescence assay.Neuron marker nucleus antigen (NeuN)and astrocyte marker glial fibrillary acidic protein (GFAP) were identified by immunofluorescent staining.The cells of third generation in their exponential phase were chosen and randomly divided into experimental group (adding GDF11 to make the final concentration as 40 ng/mL) and control group (adding equal amount of culture fluid).The proliferation of the cells in the two groups was detected by 5-ethynyl-2'-deoxyuridine (EdU) kits and protein expressions of Smad2/3,phosphorylated (p)-Smad2/3,Smad4 and β-Catenin were measured by Western blotting one and 6 h after treatment.Results Round and bright cells suspended in culture medium were observed through optical microscope.Immunofluorescence assay showed that over 90％ cells expressed both nestin and SOX2,and some of them expressed NeuN or GFAP.EdU proliferation test showed that the percentage of EdU positive cells in the experimental group (0.34±0.08) was significantly higher than that in the control group (0.24±0.03,P＜0.05).Western blotting showed that the expression levels ofp-Smad2/3,Smad4 and β-Catenin were significantly increased one and 6 h after treatment as compared with those in the control group (P＜0.05).Conclusion GDF11 can promote the proliferation of NSCs in vitro and probably is on account of activating TGF-β/Smads and Wnt/β-Catenin signal pathways.
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Objective To investigate the effects and possible mechanism of growth differentiation factor 11 (GDF11)on angiogenesis in diabetic hindlimb ischemia. Methods Sixty SD rats were used in this study. Diabetes was induced by intraperitoneal injection of streptozotocin. 3 days after streptozotocin administration, 40 rats with plasma glucose concentration≥16.7 mmol/L were selected in the subsequent experiments. 12 weeks after diabetes was induced,the left femoral artery and all the sides branches were dissected free and excised. After resection of the left femoral artery,rats were randomized to four groups:PBS group(n=10),GDF11 group(n=10),IgG Ab group (n=10),or GDF11 Ab group(n=10). After 0,7,and 14 days,the serial blood flows were measured by a Laser Doppler perfusion image(LDPI)analyzer. To detect capillary endothelial cell,the sections of muscles were reacted with anti-CD31 monoclonal antibodies,and subsequently reacted with Cy3-conjugated anti-rabbit IgG antibody. The expression levels of HIF1α and VEGF were detected by western blotting. Results In GDF11 group significantly increased the blood perfusion and capillary density of ischemia hindlimb of the diabetic rats were found,which was correlated to an increased level of HIF1α and VEGF. In contrast, GDF11 Ab could lead to the opposite effects. Conclusion GDF11 treatment promotes the recovery of diabetic hindlimb ischemia, which may be related to the improvement of expression of HIF1 alpha and VEGF.
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Objective To observe the protective effect of growth differentiation factor 11(GDF11) on myocardial injury and the changes of myocardial apoptosis in type 2 diabetic C57BL/6J mice.Methods Sixty male C57BL/6J mice weighing 20-25 g were randomly divided into three groups: control group (control), type 2 diabetes mellitus group (DM) and GDF11 intervention group (DM + GDF11).To establish mouse model of type 2 diabetes, the mice were fed with high fat and high sugar diet for 4 weeks, and i.p.injected consecutively three times of streptozotocin (STZ) in a dose of 60 mg/kg.After the continuous high-fat and high-sugar diet for 4 weeks, the cardiac function was detected by small animal ultrasound, TUNEL staining was used to detect the apoptosis in myocardium, and the expressions of cleaved-caspase-3, Bcl-2, Bax were measured.Results Diabetic injury significantly reduced the left ventricular ejection fraction and left ventricular short axis shortening rate, and increased myocardial apoptosis.Recombinant GDF11 protein significantly improved cardiac function and reduced myocardial apoptosis.Conclusions Exogenous GDF11 can significantly reduce myocardial apoptosis and improve heart function after diabetic injury.
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Objective To investigate the effect of growth differentiation factor 11 ( GDF11 ) on aorta in apolipoprotein E-Null( ApoE-/-) mice and its possible mechanisms. Methods Four-week-old healthy male ApoE-/-mice were fed with high-fat diet for 1 week and were then divided into 4 groups:vehicle group(n=10), GDF11 group (n=10),adeno-associated virus-green fluorescent protein group(AAV-GFP group, n=10), and AAV-GDF11 group ( n=10 ) . The mice received intraperitoneal injection with phosphate buffered saline, GDF11 protein, a single injection of purified AAV-GDF11 or AAV-GFP through the tail vein, respectively. After 4 weeks, serum GDF11/8 level and endothelium-dependent vasodilatation were detected. After 12 weeks, serum GDF11/8, interleukin-6 (IL-6), tumor necrosis factor-α( TNF-α), total cholesterol ( TC), triglycerides ( TG), oxidized low density lipoprotein(ox-LDL), and free fatty acids(FFA)levels were measured, the plaque areas in aortic enface and cross sections were measured by oil red O or HE staining, the macrophages/T lymphocytes infiltration in plaques were detected with immunohistochemistry, and the mRNA expressions of IL-6, TNF-α, and IL-10 were determined by real-time PCR. Results Compared with vehicle or AAV-GFP groups, GDF11 and AAV-GDF11 groups presented improved endothelium-dependent vasodilatation, decreased levels of blood inflammatory factors, blood lipid, reduced plaque on face area sections[Vehicle group : GDF11 group:(31. 23 ± 3. 12)% vs (17. 18 ± 2. 17) %;AAV-GFP group : AAV-GDF11 group:(38.01±4.43)% vs(14.54±2.86)%,P<0.05]andcrosssections[Vehiclegroup :GDF11 group:(19. 87 ± 2. 11)% vs (10. 32 ± 1. 47)%;AAV-GFP group : AAV-GDF11 group:(23. 02 ± 2. 76)%vs (9.06±1.63)%, P<0. 05]. There were less macrophages and T lymphocytes infiltration in plaques and lower mRNA expressions of inflammatory factors at aortic wall. Conclusion GDF11 reduces the area of atherosclerotic lesion in ApoE-/-mice, which may be involved in endothelial protection, such as to reduce inflammatory reaction, and to change cellular composition in plaques.
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AIM:To investigate the effect of growth differentiation factor 11 ( GDF11 ) on the expansion of CD8 +memory stem T cells ( Tscm) and to further improve the effect of adoptive immunotherapy.METHODS:Healthy human peripheral blood mononuclear cells ( PBMCs) were isolated by density gradient centrifugation at first.Among the i-solated PBMCs, CD8 +T cells were further purified with MACS microbeads.The CD8 +T cells were then randomly divided into experimental groups and control group.The same volume of different concentrations of GDF11 were added into the ex-perimental groups, and the same volume of PBS solution was added into the control group.Finally, the expansion of Tscm in experimental groups and control group was measured by flow cytometry at several time points.RESULTS:GDF11 sig-nificantly increased the number of Tscm in CD8 +T cells in vitro expansion and also dramatically increased the ratio of Tscm in CD8 +T cells.Furthermore, 400 μg/L GDF11 treatment for 3 weeks was the optimal condition to induce CD8 +Tscm. CONCLUSION:GDF11 effectively increases the number and ratio of Tscm in the CD8 +T cells in cell culture growth, thereby creating a new strategy to further improve the efficiency of adoptive immunotherapy.