Insulin-like Growth factor-I Expression Research Articles

Dietary vitamin B12 requirement of fingerling blunt snout bream Megalobrama amblycephala determined by growth performance, digestive and absorptive capability and status of the GH-IGF-I axis

This study aimed to investigate the optimal dietary vitamin B12 requirement of fingerling blunt snout bream Megalobrama amblycephala based on the results of growth performance, intestinal digestive and absorptive capability and responses of the growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis. Fish (initial body weight: 0.71±0.03g) were randomly assigned to six purified diets containing graded levels of vitamin B12 (0, 0.028, 0.051, 0.12, 0.23 and 0.41mg/kg) for 12weeks. Both weight gain (WG) and specific growth rate increased significantly (P<0.05) as dietary vitamin B12 levels increased from 0 to 0.051mg/kg, then plateaued with further increasing levels. Feed conversion ratio decreased as dietary vitamin B12 levels increased from 0 to 0.12mg/kg, but no statistical difference was observed. Whole-body composition and intestinal brush border enzymes activities also exerted little difference within the vitamin B12 range tested, whereas hepatic vitamin B12 contents increased remarkably (P<0.01) with increasing dietary vitamin B12 levels. Intestinal protease, amylase and lipase activities all increased significantly (P<0.05) as dietary vitamin B12 levels increased from 0 to 0.12mg/kg, but decreased remarkably (P<0.05) with further increasing vitamin B12 levels. Similar results were also observed in hepatic IGF-I expressions. Furthermore, the mRNA expressions of GH in the brain decreased significantly (P<0.05) with increasing dietary vitamin B12 levels. Based on the broken-line regression analysis of WG, the optimal dietary vitamin B12 requirement of fingerling blunt snout bream was estimated to be 0.06mg/kg. In addition, a supplementation of 0.12mg/kg vitamin B12 boosted intestinal digestive capability and hepatic IGF-I expression. Statement of relevanceThis study investigated the optimal dietary vitamin B12 requirement of fingerling blunt snout bream based on growth performance. The underlying mechanisms were also investigated with emphasis on intestinal digestive and absorptive capability and modulation of the GH-IGF-I axis. Data obtained here might facilitate the development of low-cost formulated feed for aquatic species.

Ginsenoside Rb1 alleviates aluminum chloride-induced rat osteoblasts dysfunction.

Osteoblasts dysfunction, induced by aluminum (Al), plays a critical role in the osteoporosis etiology. Ginsenoside Rb1 (Rb1) has the therapeutic properties for osteoporosis. This study aimed to assess the efficiency of Rb1 in ameliorating Al-induced osteoblasts dysfunction. The osteoblasts were divided into four groups: Rb1-treated group (RG, 0.0145mg/mL Rb1), control group (CG, 0), AlCl3-treated group (AG, 0.126mg/mL AlCl3·6H2O), AlCl3+Rb1-treated group (ARG, 0.0145mg/mL Rb1 and 0.126mg/mL AlCl3·6H2O). After 24h of culture, the osteoblasts viability, the transforming growth factor-β1 (TGF-β1), bone morphogenetic protein-2 (BMP-2), the insulin-like growth factor I (IGF-I), core-binding factor α1 (Cbfα1) mRNA expressions, glutathione perioxidase (GSH-Px) and superoxide dismutase (SOD) activities, and reactive oxygen species (ROS) concentration were determined. The osteoblasts ultrastructural features were also observed. In the ARG, the osteoblasts viability, TGF-β1, BMP-2, IGF-I and Cbfα1 mRNA expressions and the GSH-Px and SOD activities were significantly increased, the ROS concentration was significantly decreased, and osteoblasts histology lesion was attenuated compared with the AG. These results demonstrated that Rb1 could significantly reverse osteoblasts viability and osteoblasts growth regulation factor, inhibit oxidative stress, and attenuate histology lesion in the osteoblasts with AlCl3. These results indicate that Rb1 can effectively alleviate the AlCl3-induced osteoblasts dysfunction.

IGF-I and IGF-binding proteins in synovial fluid of patients with Lyme arthritis

Purpose: Multiple cellular functions are stimulated by a Insulin-like Growth Factor-I (IGF-I). The biological activity of IGF-I is modulated by IGFbinding proteins (IGF-BPs) and at the same time, the availability of IGF-BPs may be regulated by the proteolytic activity of some metalloproteinases (MMPs). The aim of the present study was to compare the amounts of IGF-I and IGF-BPs in relation to the activity of MMP-9 in serum and knee synovial fluid from patients with Lyme arthritis (LA) and post-traumatic damage (PTD). Material and methods: Serum and synovial fluids were taken from knee joints of patients with PTD and LA. ELISA (for IGF-I assay), polyacrylamine gel electrophoresis following Western immuneblotting (for IGF-I and IGF-BPs expression), and zymography (for metalloproteinases detection), were used. Results: The concentration of IGF-I in serum and synovial fluid from LA patients were significantly lowered in comparison to PTD patients. Interesting, the synovial fluid /serum ratio of IGF-I concentrations was also lower in LA patients. Low expression IGF-BP3 and high activity of MMP-9 were detected in the LA synovial fluid. Conclusions: The high proteolytic activity of MMP- 9 results in a cleavage of both IGF-I and IGF-BP3 causing a decrease in content of these substances in LA synovial fluid. In addition, the reduction in IGF and IGF-BP amounts may affect the repair processes in joint tissues of LA patients. The low concentration of IGF-I and IGF-BP3 slows down the repair processes in the joint tissues of LA patients.

Effects of recombinant human growth hormone on local expression of insulin-like growth factor-Ⅰ during orthodontic tooth movement

To explore in vivo the expression of insulin-like growth factor-Ⅰ(IGF-Ⅰ)under stress, and to analyze changes of the local expression related to recombinant human growth hormone(rhGH)treatment. Forty Wistar rats were randomly divided into control and growth hormone groups, 20 in each group. A force of 0.49 N was applied to move the right upper first molars mesially. The growth hormone group and control group received daily subcutaneous injections of rhGH and equivalent volumes of saline, respectively. The rats were sacrificed on days 1, 3, 7 and 14. Micro-CT-reconstructed images were used to survey root resorption, and horizontal sections of the maxillae were prepared for tartrate-resistant acid phosphate(TRAP)and immunohistochemistry staining. Tooth moved faster in the growth hormone group([0.291±0.017], [0.513±0.111]mm)than in the control group([0.245±0.033], [0.368± 0.052]mm)on days 7 and 14(P<0.05). More osteoclasts on day 3, and fewer osteoclasts on day 7 were observed in the growth hormone group([4.0±0.7], [2.6±0.6]cell/high-power field)than in the control group([2.8±0.6], [3.8±0.8]cell/high-power field)(P<0.05). The number of IGF-Ⅰ positive osteoclasts in the growth hormone group([4.7 ± 0.7]cell/high-power field)was significantly greater than that in the control group([2.7±0.5]cell/high-power field)(P<0.01)on day 3. Compared with the control group([18.6±1.5], [23.3± 3.8]cell/high-power field), IGF-Ⅰ positive PDL cells increased on days 7 and 14 in the growth hormone groups([29.6±3.4], [37.5±6.1]cell/high-power field)(P<0.01). rhGH could stimulate IGF-Ⅰ expression in PDL, and accelerate bone remodeling and tooth movement.

Rearing Mozambique tilapia in tidally-changing salinities: Effects on growth and the growth hormone/insulin-like growth factor I axis

The growth hormone (GH)/insulin-like growth factor (IGF) axis plays a central role in the regulation of growth in teleosts and has been shown to be affected by acclimation salinity. This study was aimed at characterizing the effects of rearing tilapia, Oreochromis mossambicus, in a tidally-changing salinity on the GH/IGF axis and growth. Tilapia were raised in fresh water (FW), seawater (SW), or in a tidally-changing environment, in which salinity is switched between FW (TF) and SW (TS) every 6h, for 4months. Growth was measured over all time points recorded and fish reared in a tidally-changing environment grew significantly faster than other groups. The levels of circulating growth hormone (GH), insulin-like growth factor I (IGF-I), pituitary GH mRNA, gene expression of IGF-I, IGF-II, and growth hormone receptor 2 (GHR) in the muscle and liver were also determined. Plasma IGF-I was higher in FW and TS than in SW and TF tilapia. Pituitary GH mRNA was higher in TF and TS than in FW and SW tilapia. Gene expression of IGF-I in the liver and of GHR in both the muscle and liver changed between TF and TS fish. Fish growth was positively correlated with GH mRNA expression in the pituitary, and GHR mRNA expression in muscle and liver tissues. Our study indicates that rearing fish under tidally-changing salinities elicits a distinct pattern of endocrine regulation from that observed in fish reared in steady-state conditions, and may provide a new approach to increase tilapia growth rate and study the regulation of growth in euryhaline fish.

Inflammation Promotes Expression of Stemness-Related Properties in HBV-Related Hepatocellular Carcinoma.

The expression of cancer stemness is believed to reduce the efficacy of current therapies against hepatocellular carcinoma (HCC). Understanding of the stemness-regulating signaling pathways incurred by a specific etiology can facilitate the development of novel targets for individualized therapy against HCC. Niche environments, such as virus-induced inflammation, may play a crucial role. However, the mechanisms linking inflammation and stemness expression in HCC remain unclear. Here we demonstrated the distinct role of inflammatory mediators in expressions of stemness-related properties involving the pluripotent octamer-binding transcription factor 4 (OCT4) in cell migration and drug resistance of hepatitis B virus-related HCC (HBV-HCC). We observed positive immunorecognition for macrophage chemoattractant protein 1 (MCP-1)/CD68 and OCT4/NANOG in HBV-HCC tissues. The inflammation-conditioned medium (inflamed-CM) generated by lipopolysaccharide-stimulated U937 human leukemia cells significantly increased the mRNA and protein levels of OCT4/NANOG preferentially in HBV-active (HBV+HBsAg+) HCC cells. The inflamed-CM also increased the side population (SP) cell percentage, green fluorescent protein (GFP)-positive cell population, and luciferase activity of OCT4 promoter-GFP/luciferase in HBV-active HCC cells. Furthermore, the inflamed-CM upregulated the expressions of insulin-like growth factor-I (IGF-I)/IGF-I receptor (IGF-IR) and activated IGF-IR/Akt signaling in HBV-HCC. The IGF-IR phosphorylation inhibitor picropodophyllin (PPP) suppressed inflamed-CM-induced OCT4 and NANOG levels in HBV+HBsAg+ Hep3B cells. Forced expression of OCT4 significantly increased the secondary sphere formation and cell migration, and reduced susceptibility of HBV-HCC cells to cisplatin, bleomycin, and doxorubicin. Taking together, our results show that niche inflammatory mediators play critical roles in inducing the expression of stemness-related properties involving IGF-IR activation, and the upregulation of OCT4 contributes to cancer migration and drug resistance of HBV-HCC cells. Findings in this paper would provide potential targets for a therapeutic strategy targeting on inflammatory environment for HBV-HCC.

IGF-I: A Key Growth Factor that Regulates Neurogenesis and Synaptogenesis from Embryonic to Adult Stages of the Brain.

The generation of neurons in the adult mammalian brain requires the activation of quiescent neural stem cells (NSCs). This activation and the sequential steps of neuron formation from NSCs are regulated by a number of stimuli, which include growth factors. Insulin-like growth factor-I (IGF-I) exert pleiotropic effects, regulating multiple cellular processes depending on their concentration, cell type, and the developmental stage of the animal. Although IGF-I expression is relatively high in the embryonic brain its levels drop sharply in the adult brain except in neurogenic regions, i.e., the hippocampus (HP) and the subventricular zone-olfactory bulb (SVZ-OB). By contrast, the expression of IGF-IR remains relatively high in the brain irrespective of the age of the animal. Evidence indicates that IGF-I influences NSC proliferation and differentiation into neurons and glia as well as neuronal maturation including synapse formation. Furthermore, recent studies have shown that IGF-I not only promote adult neurogenesis by regulating NSC number and differentiation but also by influencing neuronal positioning and migration as described during SVZ-OB neurogenesis. In this article we will revise and discuss the actions reported for IGF-I signaling in a variety of in vitro and in vivo models, focusing on the maintenance and proliferation of NSCs/progenitors, neurogenesis, and neuron integration in synaptic circuits.

Aerobic and resistance training dependent skeletal muscle plasticity in the colon-26 murine model of cancer cachexia

PurposeThe appropriate mode of exercise training for cancer cachexia is not well-established. Using the colon-26 (C26) mouse model of cancer cachexia, we defined and compared the skeletal muscle responses to aerobic and resistance training. MethodsTwelve-month old Balb/c mice were initially assigned to control, aerobic training (AT; wheel running), or resistance training (RT; ladder climbing) (n=16–17/group). After 8weeks of training, half of each group was injected with C26 tumor cells, followed by 3 additional weeks of training. Body composition and neuromuscular function was evaluated pre- and post-training. Muscles were collected post-training and analyzed for fiber cross-sectional area (CSA), Akt–mTOR signaling, and expression of insulin-like growth factor-I (IGF-I) and myogenic regulatory factors. ResultsTotal body mass decreased (p<0.05) in C26 (−8%), AT+C26 (−18%), and RT+C26 (−15%) but not control. Sensorimotor function declined (p<0.05) in control (−16%), C26 (−13%), and RT+C26 (−23%) but not AT+C26. Similarly, strength/body weight decreased (p<0.05) in control (−7%), C26 (−21%), and RT+C26 (−10%) but not AT+C26. Gastrocnemius mass/body weight tended to be greater in AT+C26 vs. C26 (+6%, p=0.09). Enlargement of the spleen was partially corrected in AT+C26 (−27% vs. C26, p<0.05). Fiber CSA was lower in all C26 groups vs. control (−32% to 46%, p<0.05); however, the effect size calculated from C26 and AT+C26 was large (+24%, d=1.04). Phosphorylated levels of mTOR in AT+C26 exceeded C26 (+32%, p<0.05). RT+C26 showed greater mRNA expression (p<0.05) of IGF-IEa (+79%) and myogenin (+126%) with a strong tendency for greater IGF-IEb (+127%, p=0.069) vs. control. ConclusionsAerobic or resistance training was unable to prevent tumor-induced body weight loss. However, aerobic training may have preserved function, reduced the inflammatory response of the spleen, and marginally rescued muscle mass possibly through activation of mTOR. Aerobic training may therefore have therapeutic value for patients with cancer cachexia. In contrast, resistance training induced the expression of genes associated with muscle damage and repair. This gene response may be supportive of excessive stress generated by high resistance loading in a tumor-bearing state.

Local trauma in human patellar tendon leads to widespread changes in the tendon gene expression.

Low cellular activity and slow tissue turnover in human tendon may prolong resolution of tendinopathy. This may be stimulated by moderate localized traumas such as needle penetrations, but whether this results in a widespread cellular response in tendons is unknown. In an initial hypothesis-generating study, a trauma-induced tendon cell activity (increased total RNA and collagen I mRNA) was observed after repeated patellar tendon biopsies in young men. In a subsequent controlled study, 25 young men were treated with two 0.8-mm-diameter needle penetrations [n = 13, needle-group (NG)] or one 2.1-mm-diameter needle biopsy [n = 12, biopsy-group (BG)] in one patellar tendon. Four weeks later biopsies were taken from treated (5 mm lateral from trauma site) and contralateral tendons for analyses of RNA content (ribogreen assay), DNA content (PCR based), and gene expression for relevant target genes (Real-time RT-PCR) (NG, n = 11 and BG, n = 8). Intervention increased RNA content, and mRNA expression of collagen I and III and TGF-β1 (P < 0.05), with biopsy treatment having greatest effect (tendency for RNA and collagen I). Results for DNA content were inconclusive, and no changes were detected in expression of insulin-like growth factor-I, connective tissue growth factor, scleraxis, decorin, fibromodulin, tenascin-C, tenomodulin, VEGFa, CD68, IL-6, MMP12, and MMP13. In conclusion, a moderate trauma to a healthy human tendon (e.g., biopsy sampling) results in a widespread upregulation of tendon cell activity and their matrix protein expression. The findings have implications for design of studies on human tendon and may provide perspectives in future treatment strategies in tendinopathy.

Oral administration of synthetic porcine beta-defensin-2 improves growth performance and cecal microbial flora and down-regulates the expression of intestinal toll-like receptor-4 and inflammatory cytokines in weaned piglets challenged with enterotoxigenic Escherichia coli.

Synthetic porcine beta-defensin-2 (pBD-2) was tested as an alternative to antimicrobial growth-promoters in pig production. Thirty 21-day weaned piglets were challenged with enterotoxigenic Escherichia coli, and orally dosed with either sterile water (CON), pBD-2 (BD) or neomycin sulphate (NS) twice daily for 21 days. pBD-2 and NS led to higher growth performance, jejunum villus height and increased expression of insulin-like growth factor-I compared with the CON group (P < 0.05). Hemolytic E. coli scores from rectal swabs, and copy numbers of E. coli, Bacteroides fragilis and Streptococcus in the cecal digesta of the BD- or NS-treated piglets were lower than those in the CON group (P < 0.05). Messenger RNA levels of toll-like receptor 4, tumor necrosis factor-α, interleukin (IL)-1β, and IL-8 in the jejunum mucosa of the BD and NS groups were lower than those in the CON group (P < 0.05). Copy numbers of Lactobacilli and Bifidobacteria in the cecal digesta of the BD group were higher than those of the CON and NS groups (P < 0.05). Therefore, pBD-2 has antimicrobial activity in piglets, and it can improve growth performance, reduce inflammatory cytokine expression and affect intestinal morphological indices in the same way as probiotics. © 2015 Japanese Society of Animal Science.

Dietary methionine level influences growth and lipid metabolism via GCN2 pathway in cobia (Rachycentron canadum)

This study investigated the effect of dietary methionine level on growth and lipid metabolism via the general control nonderepressible2 kinase (GCN2) pathway in cobia (Rachycentron canadum). Cobia were fed diets with six levels of methionine (0.62%, 0.84%, 1.02%, 1.15%, 1.25% and 1.42% of dry diet) with a constant cystine level (0.42% dry diet). The feeding experiment began in September 2013 and ended in December 2013; during the experiment, cobia were fed ad libitum twice daily (7:00 and 18:00h) for 10weeks. Cobia fed the diet with 1.02% methionine showed elevated weight gain (WG) and feed efficiency ratio (FER) compared with those fed the other diets (P<0.05). The content of liver lipid, total triglyceride, and total cholesterol were first enhanced significantly with increasing dietary methionine level from 0.62% to 1.02%, and then decreased markedly with higher levels of dietary methionine level (1.02% to 1.42%). Crude lipid was markedly elevated when the dietary methionine level was 1.02%, and then plateaued with higher dietary methionine level. The expression of genes associated with hepatic lipid synthesis (sterol regulatory element binding protein-1, peroxisome proliferator activated receptor γ, fatty acid synthetase, and stearoyl-CoA desaturase-1) were markedly up-regulated in fish fed the diet containing 1.02% methionine, whereas the transcriptional levels of lipolytic genes (peroxisome proliferator activated receptor α, carnitine acyl transferase-1, and lipase lipoprotein lipase) were elevated in fish fed the methionine-deficient diet (0.62%; P<0.05). The expression of insulin-like growth factor-I (IGF-I) was suppressed by the methionine-deficient diet, whereas the hepatic mRNA expression levels of genes related to amino acid responses (AAR), i.e., GCN2, activating transcription factor 4 (ATF4), CCAAT enhancer binding protein β (C/EBPβ), and asparagine synthetase (ASNS), were significantly up-regulated. In conclusion, the dietary methionine requirement of cobia was estimated to be 1.04% and 1.15% of dry matter (2.23% and 2.45% dietary protein) on the basis of WG and FER, respectively. Results of this study suggested that methionine deficiency could suppress growth, decrease lipid content, and inhibit expression of IGF-I and some genes related to lipid synthesis in cobia; these changes might be regulated by inducing the expression of genes related to the GCN2 pathway (GCN2, ATF4, C/EBPβ, and ASNS). Statement of relevanceThe present study was conducted to investigate the effect of dietary methionine on growth performance, plasma biochemical indexes, lipid content and gene expression involved in lipid metabolism and GCN2 pathway in cobia (Rachycentron canadum). Our findings have showed that methionine deficiency could suppress growth, decrease lipid content and inhibit expressions of IGF-I and some lipid synthesis related genes of cobia, which may be regulated by inducing the mRNA expressions of GCN2 pathway related genes (GCN2, ATF4, C/EBPβ and ASNS). The results are reliable and of both theoretical and practical importance.The work described has not been submitted elsewhere for publication, in whole or in part, and all the authors listed have approved the manuscript that is enclosed. I have read and have abided by the statement of ethical standards for manuscripts submitted to Aquaculture.

Cotransfected human chondrocytes: over-expression of IGF-I and SOX9 enhances the synthesis of cartilage matrix components collagen-II and glycosaminoglycans.

Damage to cartilage causes a loss of type II collagen (Col-II) and glycosaminoglycans (GAG). To restore the original cartilage architecture, cell factors that stimulate Col-II and GAG production are needed. Insulin-like growth factor I (IGF-I) and transcription factor SOX9are essential for the synthesis of cartilage matrix, chondrocyte proliferation, and phenotype maintenance. We evaluated the combined effect of IGF-I and SOX9 transgene expression on Col-II and GAG production by cultured human articular chondrocytes. Transient transfection and cotransfection were performed using two mammalian expression plasmids (pCMV-SPORT6), one for each transgene. At day 9 post-transfection, the chondrocytes that were over-expressing IGF-I/SOX9 showed 2-fold increased mRNA expression of the Col-II gene, as well as a 57% increase in Col-II protein, whereas type I collagen expression (Col-I) was decreased by 59.3% compared with controls. The production of GAG by these cells increased significantly compared with the controls at day 9 (3.3- vs 1.8-times, an increase of almost 83%). Thus, IGF-I/SOX9 cotransfected chondrocytes may be useful for cell-based articular cartilage therapies.

Chondrogenic Differentiation Processes in Human Bone Marrow Aspirates upon rAAV-Mediated Gene Transfer and Overexpression of the Insulin-Like Growth Factor I.

Direct therapeutic gene transfer in marrow concentrates is an attractive strategy to conveniently enhance the chondrogenic differentiation processes as a means to improve the healing response of damaged articular cartilage upon reimplantation in sites of injury. In the present study, we evaluated the ability of the clinically adapted recombinant adeno-associated virus (rAAV) vectors to mediate overexpression of the insulin-like growth factor I (IGF-I) in human bone marrow aspirates that may modulate the proliferative, anabolic activities, and chondrogenic differentiation potential in such samples in vitro. The results demonstrate that successful, significant rAAV-mediated IGF-I gene transfer and expression were achieved in transduced aspirates (up to 105.9±35.1 pg rhIGF-I/mg total proteins) over time (21 days) at very high levels (∼80% of cells expressing the candidate IGF-I transgene), leading to increased levels of proliferation, matrix synthesis, and chondrogenic differentiation over time compared with the control (lacZ) condition. Treatment with the candidate IGF-I vector also stimulated the hypertrophic and osteogenic differentiation processes in the aspirates, suggesting that the regulation of IGF-I expression through rAAV will be a prerequisite for future translation of the approach in vivo. However, these findings show the possible benefits of this vector class to directly modify marrow concentrates as a convenient tool for strategies that aim at improving the repair of articular cartilage lesions.

The relative expression levels of insulin-like growth factor 1 and myostatin mRNA in the asynchronous development of skeletal muscle in ducks during early development

Genetic selection is a powerful tool for modifying poultry muscle yield. Insulin-like growth factor I (IGF-I) and myostatin (MSTN) are important regulators of muscle growth, especially in the myogenesis stage. This study compared the developmental pattern of the pectoralis major (PM) and lateral gastrocnemius (LM) muscles, mRNA expression characterization of IGF-I and MSTN-A and their correlation between 14days in ovo and 1week post-hatch in two Chinese local duck breeds. During early development, the growth of duck PM and LM followed an asynchronous pattern. Variations in PM growth rate observed with development followed the relative variations of MSTN and IGF-I expression; however, the same behavior was not observed in LM. Moreover, the profile of IGF-I expression in duck skeletal muscles indicated that genetic selection for high meat-yield poultry has altered the temporal expression of IGF-I and affected cellular characteristics and mass by hatch in a PM-specific manner. The MSTN-A expression profile showed synchronization with the growth of skeletal muscle and peaks of myofiber proliferation. The expression patterns of IGF-I and MSTN suggest that duck pectoralis fibers are prioritized for proliferation in embryogenesis. The IGF-1/MSTN-A mRNA ratios in PM and LM presented very similar trends in the changes of myofiber characteristics, and differences in the IGF-1/MSTN-A mRNA ratio in PM between the two breeds corresponded to the timing of differences in PM mass between the varieties. Our results support the hypothesis that relative levels of IGF-I and MSTN mRNA may participate in ordering muscle growth rates with selected development.

In Ovo Administration of Silver Nanoparticles and/or Amino Acids Influence Metabolism and Immune Gene Expression in Chicken Embryos

Due to their physicochemical and biological properties, silver nanoparticles (NanoAg) have a wide range of applications. In the present study, their roles as a carrier of nutrients and an immunomodulator were tested in chicken embryos. Cysteine (Cys)+NanoAg injected embryos had smaller livers but heavier breasts on the 19th day of embryogenesis. Cys injected embryos had lower oxygen consumption compared to threonine (Thr) or NanoAg injected embryos. The energy expenditure in Thr+NanoAg, or NanoAg injected embryos was higher than Cys or Cys+NanoAg but was not different from uninjected control embryos. Relative expression of the hepatic insulin-like growth factor-I (IGF-I) gene was higher in Cys or NanoAg injected embryos after lipopolysaccharide (LPS) induction. The gene expression of hepatic tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) did not differ among amino acids, NanoAg and uninjected controls in the non-LPS groups, but increased by many folds in the LPS treated NanoAg, Cys and Cys+NanoAg groups. In LPS treated spleens, TNF-α expression was also up-regulated by NanoAg, amino acids and their combinations, but interleukin-10 (IL-10) expression was down-regulated in Thr, Cys or Thr+NanoAg injected embryos. Toll like receptor-2 (TLR2) expression did not differ in NanoAg or amino acids injected embryos; however, toll like receptor-4 (TLR4) expression was higher in all treated embryos, except for Cys+NanoAg, than in uninjected control embryos. We concluded that NanoAg either alone or in combination with amino acids did not affect embryonic growth but improved immunocompetence, indicating that NanoAg and amino acid complexes can act as potential agents for the enhancement of innate and adaptive immunity in chicken.

Wnt/β-Catenin Small-Molecule Inhibitor CWP232228 Preferentially Inhibits the Growth of Breast Cancer Stem-like Cells.

Breast cancer stem cells (BCSC) are resistant to conventional chemotherapy and radiotherapy, which may destroy tumor masses but not all BCSC that can mediate relapses. In the present study, we showed that the level of Wnt/β-catenin signaling in BCSC is relatively higher than in bulk tumor cells, contributing to a relatively higher level of therapeutic resistance. We designed a highly potent small-molecule inhibitor, CWP232228, which antagonizes binding of β-catenin to T-cell factor (TCF) in the nucleus. Notably, although CWP232228 inhibited the growth of both BCSC and bulk tumor cells by inhibiting β-catenin-mediated transcription, BCSC exhibited greater growth inhibition than bulk tumor cells. We also documented evidence of greater insulin-like growth factor-I (IGF-I) expression by BCSC than by bulk tumor cells and that CWP232228 attenuated IGF-I-mediated BCSC functions. These results suggested that the inhibitory effect of CWP232228 on BCSC growth might be achieved through the disruption of IGF-I activity. Taken together, our findings indicate that CWP232228 offers a candidate therapeutic agent for breast cancer that preferentially targets BCSC as well as bulk tumor cells.

Effects of methionine supplementation on the expression of protein deposition-related genes in acute heat stress-exposed broilers.

The objective of this study was to evaluate the effect of heat stress and methionine supplementation on the gene expression of insulin-like growth factor I (IGF-I), growth hormone receptor (GHR), phosphatidylinositol 3-kinase, and regulatory 1 (PI3KR1) in the liver, as well as the expression of the atrogin 1 and cathepsin L2 (CTSL2) genes in the breast muscle of broilers. Broilers from 1–21 and 22–42 days of age were divided into three treatments related to methionine supplementation as follows: without methionine supplementation (MD), recommended level of methionine (DL1), and excess supplementation of methionine (DL2). The animals were either maintained at a thermal comfort temperature or exposed to heat stress (HS) (38°C for 24 hours, starting on day 20 or day 41 for experiments 1 and 2, respectively). The heat stress increased the body temperature at both ages. Starter period: The HS animals presented increased plasma creatinine content (P<0.0001) and the highest CTSL2 gene expression (P<0.0001). The methionine supplementation increased the IGF-I (P = 0.0144) and GHR (P = 0.0011) gene expression and decreased the CTSL2 (P = 0.0004) and atrogin 1 (P = 0.0012) gene expression. Grower period: Significant effects for the interaction between supplementation and environment were observed for GHR (P = 0.0252) and CTSL2 (P = 0.0011) gene expression. The highest GHR expression was observed in animals that remained in thermal comfort on the DL2 diet, and the lowest expression occurred in the HS animals fed the MD diet. For CTSL2, the HS animals fed the MD diet presented the highest CTSL2 gene expression, and the lowest expression was observed in the animals maintained at thermal comfort on DL1 and DL2 diets. Only methionine supplementation had effect on atrogin-1 gene expression (P<0.0001), with higher methionine content in the diet lower atrogin-1 gene expression was observed. Our results suggest that heat stress induces greater protein degradation and that methionine supplementation could induce protein deposition because methionine increased the expression of genes related to protein synthesis and decreased the expression of genes related to protein breakdown.

Loss of survival factors and activation of inflammatory cascades in brain sympathetic centers in type 1 diabetic mice.

Neuroinflammation and neurodegeneration have been observed in the brain in type 1 diabetes (T1D). However, little is known about the mediators of these effects. In T1D mice with 12- and 35-wk duration of diabetes we examined two mechanisms of neurodegeneration, loss of the neuroprotective factors insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) and changes in indoleamine 2,3-dioxygenase (IDO) expression in the brain, and compared the response to age-matched controls. Furthermore, levels of matrix metalloproteinase-2 (MMP-2), nucleoside triphosphate diphosphohydrolase-1 (CD39), and ionized calcium-binding adaptor molecule 1 (Iba-1) were utilized to assess inflammatory changes in astrocytes, microglia, and blood vessels. In the diabetic hypothalamus (HYPO), we observed 20% reduction in neuronal soma diameter (P<0.05) and reduced neuronal expression of IGFBP-3 (-32%, P<0.05) and IGF-I (-15%, P<0.05) compared with controls at 35 wk. In diabetic HYPO, MMP-2 expression was increased in astrocytes (46%, P<0.01), and IDO⁺ cell density rose by (62%, P<0.05). CD39 expression dropped by 30% (P<0.05) in microglia and blood vessels. With 10 wk of systemic treatment using minocycline, an anti-inflammatory agent that crosses the blood-brain barrier, MMP-2, IDO, and CD39 levels normalized (P<0.05). Our results suggest that increased IDO and early loss of CD39⁺ protective cells lead to activation of inflammation in sympathetic centers of the CNS. As a downstream effect, the loss of the neuronal survival factors IGFBP-3 and IGF-I and the neurotoxic products of the kynurenine pathway contribute to the loss of neuronal density observed in the HYPO in T1D.

Myostatin and IGF-I signaling in end-stage human heart failure: a qRT-PCR study.

BackgroundMyostatin (Mstn) is a key regulator of heart metabolism and cardiomyocyte growth interacting tightly with insulin-like growth factor I (IGF-I) under physiological conditions. The pathological role of Mstn has also been suggested since Mstn protein was shown to be upregulated in the myocardium of end-stage heart failure. However, no data are available about the regulation of gene expression of Mstn and IGF-I in different regions of healthy or pathologic human hearts, although they both might play a crucial role in the pathomechanism of heart failure.MethodsIn the present study, heart samples were collected from left ventricles, septum and right ventricles of control healthy individuals as well as from failing hearts of dilated (DCM) or ischemic cardiomyopathic (ICM) patients. A comprehensive qRT-PCR analysis of Mstn and IGF-I signaling was carried out by measuring expression of Mstn, its receptor Activin receptor IIB (ActRIIB), IGF-I, IGF-I receptor (IGF-IR), and the negative regulator of Mstn miR-208, respectively. Moreover, we combined the measured transcript levels and created complex parameters characterizing either Mstn- or IGF-I signaling in the different regions of healthy or failing hearts.ResultsWe have found that in healthy control hearts, the ratio of Mstn/IGF-I signaling was significantly higher in the left ventricle/septum than in the right ventricle. Moreover, Mstn transcript levels were significantly upregulated in all heart regions of DCM but not ICM patients. However, the ratio of Mstn/IGF-I signaling remained increased in the left ventricle/septum compared to the right ventricle of DCM patients (similarly to the healthy hearts). In contrast, in ICM hearts significant transcript changes were detected mainly in IGF-I signaling. In paralell with these results miR-208 showed mild upregulation in the left ventricle of both DCM and ICM hearts.ConclusionsThis is the first demonstration of a spatial asymmetry in the expression pattern of Mstn/IGF-I in healthy hearts, which is likely to play a role in the different growth regulation of left vs. right ventricle. Moreover, we identified Mstn as a massively regulated gene in DCM but not in ICM as part of possible compensatory mechanisms in the failing heart.

Protective effect of aqueous extracts from Rhizopus oryzae on liver injury induced by carbon tetrachloride in rats.

Hepatoprotective effects of Rhizopus oryzae/ U-1 aqueous extract (RU) were demonstrated in carbon tetrachloride (CCl4 )-induced liver-injured rats. In order to investigate the RU effects, the rats were administered RU at a dose of 10 or 100 mg/kg of body weight for 10 days before induction of the liver injury by oral administration of CCl4 (125 mg/kg body weight). (i) Pretreatment with RU caused a significant decrease in serum lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities that were increased by the administration of CCl4 . (ii) RU pretreatment (100 mg/kg) increased 5-bromo-2'-deoxyuridine incorporation at 48 h after CCl4 treatment in hepatocytes. (iii) Histological hematoxylin and eosin staining of the liver showed that RU pretreatment reduced the damage induced by CCl4 administration. (iv) Reverse transcriptase PCR analysis showed RU retreatment caused a transient but significant increase in hepatocyte growth factor (HGF) and a sustained and significant increase in insulin-like growth factor-I (IGF-I) gene expression in hepatocytes injured by CCl4 treatment. From these results, we conclude that oral pre-administration of RU was effective to suppress liver injury induced by the subsequent oral CCl4 administration, and RU-induced increase in IGF-I and HGF gene expression may be, even in part, involved in biological actions of RU in rats.