Insulin-like Growth factor-I mRNA Research Articles

Local application of engineered insulin-like growth factor I mRNA demonstrates regenerative therapeutic potential in vivo

Insulin-like growth factor I (IGF-I) is a growth-promoting anabolic hormone that fosters cell growth and tissue homeostasis. IGF-I deficiency is associated with several diseases, including growth disorders and neurological and musculoskeletal diseases due to impaired regeneration. Despite the vast regenerative potential of IGF-I, its unfavorable pharmacokinetic profile has prevented it from being used therapeutically. In this study, we resolved these challenges by the local administration of IGF-I mRNA, which ensures desirable homeostatic kinetics and non-systemic, local dose-dependent expression of IGF-I protein. Furthermore, IGF-I mRNA constructs were sequence engineered with heterologous signal peptides, which improved invitro protein secretion (2- to 6-fold) and accelerated invivo functional regeneration (16-fold) over endogenous IGF-I mRNA. The regenerative potential of engineered IGF-I mRNA was validated in a mouse myotoxic muscle injury and rabbit spinal disc herniation models. Engineered IGF-I mRNA had a half-life of 17-25h in muscle tissue and showed dose-dependent expression of IGF-I over 2-3days. Animal models confirm that locally administered IGF-I mRNA remained at the site of injection, contributing to the safety profile of mRNA-based treatment in regenerative medicine. In summary, we demonstrate that engineered IGF-I mRNA holds therapeutic potential with high clinical translatability in different diseases.

Effects of age and seasonal temperatures on cortisol levels and GHR, IGF-I, and IGF-II expressions in rainbow trout (Oncorhynchus mykiss)

The growth hormone (GH)/insulin-like growth factor (IGF) endocrine axis regulates the cellular growth and organ development in related to changing environmental conditions and age. The aim of this study is to determine growth factor genes, which are biological markers of growth in muscle and liver of rainbow trout (Oncorhynchus mykiss) in different seasonal temperatures and age ranges and the reveal of the relationship between serum cortisol (COR) levels from stress parameters. No difference was found in serum COR levels between the groups with respect to temperature and age. Serum GH levels were found to be higher in the summer juvenile trout compared to the winter juvenile and adult trouts. There was no difference in liver growth hormone receptor (GHR) mRNA levels of juvenile and adult trouts in winter while insulin-like growth factor-I (IGF-I) and insulin-like growth factor-II (IGF-II) mRNA levels in liver and muscle tissues were found to be higher in juvenile trout compared to adults. Among trout of different ages, GHR, IGF-I and IGF-II mRNA levels in liver in summer were higher for juvenile trout compared to adults. Muscle IGF-I mRNA levels in summer were higher in adult trout compared to juveniles. IGF-II mRNA levels in liver and muscle tissues of juvenile trout showed an increase in winter compared to in summer. While the GHR and IGF-II mRNA levels in the liver tissue of adult trout were observed to higher in winter compared to summer, IGF-I mRNA levels were found to be higher in summer. GHR, IGF-I and IGF-II mRNA levels in muscle tissue of adult trout were found to be higher in summer than in winter. This study indicated that juvenile and adult rainbow trout (Oncorhynchus mykiss) are adapted to both winter and summer temperature and that GHR, IGF-I and IGF-II genes are highly expressed.

Abomasal Nitrogen Flow Affects the Relationship between Dietary Nitrogen and Insulin-Like Growth Factor-I in Growing Lambs

Twelve abomasally cannulated wether lambs were fed isocaloric diets containing 9, 12 or 15% crude protein to determine insulin-like growth factor-I (IGF-I) responses to altered abomasal nitrogen flow and nitrogen status. Lambs were offered 1100 g/d of their respective diets. Voluntary feed consumption was not affected by nitrogen intake. Ruminal and total tract digestibilities of dry matter, organic matter and nitrogen increased linearly (P < 0.05) with increased dietary nitrogen. Abomasal flows of total, bacterial and rumen escape nitrogen increased (linear, P < 0.01), whereas dry matter and organic matter flows decreased (linear, P < 0.01). Total amino acid flow was greater (linear, P < 0.01) in lambs fed additional nitrogen due to increased (linear, P < 0.01) flows of essential and nonessential amino acids. Nitrogen retention and blood urea nitrogen increased linearly (P < 0.01). Serum IGF-I concentrations and relative hybridization intensity of hepatic IGF-I mRNA increased (linear, P < 0.05) as lambs consumed more nitrogen. Serum IGF-I and hepatic IGF-I mRNA were correlated positively (P < 0.05) with nitrogen intake and abomasal flows of nitrogen and various amino acids. These data provide evidence of a relationship between abomasal amino acid flow, as influenced by nitrogen intake, and hepatic gene expression and serum concentrations of IGF-I in growing lambs.

Nano Zinc Oxide Improves Performance, IGF-I mRNA Expression, Meat Quality, and Humeral Immune Response and Alleviates Oxidative Stress and NF-κB Immunohistochemistry of Broiler Chickens

A 35-day trial was set to explore the effects of different dietary zinc sources on growth, insulin-like growth factor I (IGF-I) mRNA expression, meat quality, immune response, antioxidant activity, and immunohistochemistry of nuclear factor kappa B (NF-κ7B) of broiler chickens. Ross 308 broiler chicks (n = 156) were randomly assigned into four experimental groups. The G1 received the basal control diet without zinc supplementation; the G2, G3, and G4 were supplemented with zinc oxide, zinc lysine, and nano zinc oxide, respectively, at a level of 40 mg Zn/kg diet. The data revealed that nano zinc oxide linearly improved the overall growth performance parameters. Nano zinc oxide linearly elevated (P < 0.001) mRNA expression of IGF-I followed by G3. The pH value of breast muscle in G4 shows a linearly decreasing value (P < 0.001). Also, the linearly highest expressible release volume percentage and lightness (L*) value with the lowest redness (a*) value (P < 0.05) were recorded in G4 and G3. A numerical increase in the total antibody titer was recorded on the 35th day in the G3 and G4. A numerical elevation in the superoxide dismutase (SOD) and a numerical reduction in the serum malondialdehyde (MDA) were recorded in the G4. The section of the liver from G4 revealed significantly very low expression of NF-κB staining. It is concluded that nano zinc oxide is considered the more trending zinc source. It had no negative effects on the health status and can be used in broiler diet premix.

Hydrolysed fish protein powder is better at the growth performance, hepatopancreas and intestinal development of Pacific white shrimp (Litopenaeus vannamei)

The effect of hydrolysed fish protein powder (HFP) on the growth, aspartate transaminase (AST) and alanine transaminase (ALT) content in the serum, malondialdehyde (MDA) and superoxide dismutase (SOD) content in the hepatopancreas, total protease, trypsin, and chymotrypsin in the intestine of Pacific white shrimp (Litopenaeus vannamei) was assessed after an 8-week experiment. Pacific white shrimps were fed six isonitrogenous (39%) and isolipidic (8%) diets with 0% (CT), 1% (T1), 2% (T2), 2.5% (T3), 3% (T4) and 4% (T5) HFP. A positive effect on weight gain rate, survival rate and feed conversion ratio was observed in shrimp fed HFP diets. In the serum, AST and ALT levels were significantly high in the T1 group compared to the other groups (P < 0.05). Total protease, trypsin and chymotrypsin were significantly high in the T4 group than in the CT group (P < 0.05). The insulin-like growth factor-I mRNA expression level in the intestine, hepatopancreas and muscle were significantly high in shrimp fed HFP diet compared to the CT group (P < 0.05). Muribaculaceae, Lactobacillus, and Lachnospiraceae were the most abundant bacteria at the genus level in the intestine. Results from this study suggest HFP has a positive effect on the growth and intestinal development of Pacific white shrimp.

Growth and Hepatic Insulin-Like Growth Factor-I Gene Expression in Dominant and Subordinate Oreochromis Niloticus L Under Limited Period of Physical Interaction

Social stress is known to regulate several aspects of the teleost physiology. This study explored the influence of limited period of physical interaction on growth and hepatic insulin-like growth factor-I (IGF-I) messenger RNA (mRNA) expression of the fish. Twenty all-male Oreochromis niloticus were isolated for 10 days and were used in a social pair study. After the social interaction was settled, dominant and subordinate individuals in a pair were reared separately in one aquarium separated by glass divider. The fish were fed at the same rate daily to remove the possible effect of nutrition. The glass divider was removed 10 min daily for social interaction. Weight was monitored on Days 2, 7 and 14 during the experimental period, then hepatic IGF-I mRNA expression was quantified. During the 14 days social experiment, mean specific growth rate of dominant fish (1.6%·day−1) was significantly higher (P<0.01) than that of the subordinate fish (0.9%·day−1). Dominant fish also had 2.5 fold significantly higher (P<0.05) mean IGF-I mRNA expression than that of subordinate fish. These indicate that even under limited period of physical contact but with period of visual communication, social status regulates growth and hepatic IGF-I gene expression in this species of fish. There was also a significant positive correlation (r = 0.52; P<0.01) between growth and IGF-I mRNA level which supports the previous studies that hepatic IGF-I gene expression has a potential utility as an instantaneous growth rate indicator for O. niloticus.

α7 Nicotinic Acetylcholine Receptor Agonists Regulate Inflammation and Growth Hormone Resistance in Sepsis.

During sepsis the normal induction of circulating insulin-like growth factor-I (IGF-I) by growth hormone (GH) action on liver is attenuated, a phenomenon called hepatic GH resistance. Hepatic GH resistance can be caused by cytokine-mediated activation of the NF-κB pathway which interferes with normal GH-signaling. The afferent and efferent fibers of the vagus nerve are integral to the cholinergic anti-inflammatory pathway (CAP) which attenuates hepatic TNFα production by activating the α7 nicotinic acetylcholine receptor (α7nAChR). We examined the effects of selective afferent vagotomy (SAV) and α7nAChR activation on sepsis-induced mortality, hepatic and systemic inflammation, the GH/IGF system and hepatic GH resistance using Sprague Dawley (SD) rats, C57BL/6 wild type (WT) mice, and α7nAChR knockout (KO) mice. Capsaicin was used to perform SAV and GTS-21 (α7nAChR agonist) was used to activate the α7nAChR. Sepsis-induced mortality, hepatic NF-κB activation, and plasma cytokine levels were increased in SAV rats and reduced in GTS-21-treated mice. The effects of sepsis on the GH/IGF-I system plasma IGF-I, IGF binding protein-1 (IGFBP-1), hepatic IGF-I, IGFBP-1, and GH receptor (GHR) mRNA and rhGH-responsiveness in mice were improved by GTS-21. Collectively these results confirm the protective effects of the anti-inflammatory CAP and α7nAChR activation in sepsis. They also provide evidence the CAP and α7nAChR activation could be used to attenuate hepatic GH resistance and anabolic failure in sepsis.

Association of growth hormone and insulin-like growth factor I genotype with body weight, dominance of body weight, and mRNA expression in Korat slow-growing chickens.

ObjectiveGrowth hormone (GH) and insulin-like growth factor I (IGF-I) play a critical role in animal growth rates. We aimed to investigate the effect of GH and IGF-I genotypes on body weight (BW), dominance, and gene expression in slow-growing chickens at different ages.MethodsA total of 613 Korat chickens (KRs) were bred and divided into three groups by genotype – A1A1, A1A3, and A3A3 for GH and AA, AC, and CC for IGF-I. Chickens were weighed every two weeks, and liver and breast muscle tissues were collected at 10 weeks of age. Genetic parameters of KRs were estimated using ASReml software. The GH and IGF-I mRNA levels were measured by quantitative polymerase chain reaction. Significant differences between traits were analyzed using the generalized linear model.ResultsA significant effect of GH genotypes on BW was found at most ages, and the A1A1 genotype had the highest value of BW. Compared with the A3A3 genotype, the A1A1 and A1A3 genotypes showed a higher dominance effect at 0 and 2 weeks, and genotype A1A1 had the highest value of dominance at 8 weeks of age. A difference in GH mRNA levels between genotypes was detected in breast muscle at 6 weeks and in the liver tissue at 2 weeks. In the case of IGF-I gene, the AA genotype had the highest BW at the beginning of life. Significant differences in BW dominance were found at 2 weeks. However, IGF-I mRNA levels were not different among genotypes in both breast muscles and liver tissues.ConclusionOur results revealed that GH and IGF-I influence growth, but may not be involved in heterosis. GH can be used as a marker gene in selection programs for growth because the homozygous genotype (A1A1) had the highest BW at all ages. The IGF-I is not a useful marker gene for selection programs.

Effects of TGF-β1 on the expression of endometrial stromal cell-related protein and mRNA.

To investigate the effects of transforming growth factor β1 (TGF-β1) on α-smooth muscle actin (α-SMA), insulin-like growth factor I (IGF-I), and type I collagen (Col I) expression in endometrial stromal cells as well as on fibronectin (FN) level. 56 patients with normal endometrial tissue obtained from surgery were selected from June 2018 to November 2019. Endometrial stromal cells were isolated from patients and then assigned to the control group and observation group (addition of TGF-β1) followed by the analysis of cellular activity by Thiazole blue staining; and α-SMA, IGF-I, Col I, and FN mRNA and protein levels by real-time fluorescent PCR and Western blot. The cell proliferation rate at 12 h, 24 h, 36 h, and 72 h after culture in both groups was higher than 0 h (p < 0.05) with higher cell proliferation in the observation group than the control group (p < 0.05). Real-time fluorescence PCR results showed that the levels of α-SMA, IGF-I, Col I, and FN mRNA in endometrial stromal cells of the observation group after TGF-β1 intervention were higher than those in the control group (p < 0.05). Meanwhile, α-SMA, IGF-I, Col I, and FN protein level was also elevated in the observation group after TGF-β1 treatment (p < 0.05). TGF-β1 can stimulate the proliferation of endometrial stromal cells, which may be related to regulate α-SMA, IGF-I, Col I, and FN expression.

Growth, stress and non-specific immune responses of turbot (Scophthalmus maximus) larvae exposed to different light spectra

The welfare of farmed fish is an important issue in aquaculture. There is particular concern regarding ambient light in culture systems. In the current study, turbot (Scophthalmus maximus) larvae were exposed to four different light spectra: full spectrum (LDF), blue (LDB, peak at 450 nm), orange (LDO, peak at 595 nm) and red (LDR, peak at 629 nm) from the embryo stage to 60 days post hatching (dph). During this time, the growth and immune response of the turbot were evaluated. Whole fish tissue samples were collected and weighed. mRNA expression levels of insulin-like growth factor-I (IGF-I), heat shock protein 70 (HSP70), glutathione S-transferase (GST), catalase (CAT), metallothionein (MT), lysozyme (LZM), cathepsin D (CTSD), cathepsin F (CTSF) and the enzyme activity of superoxide dismutase (SOD), CAT, and peroxidase (POD) were measured at 10, 20, 30, 40, 50, and 60 dph. The results showed that LDB had a positive effect on the growth of turbot larvae at 20, 40, 50 and 60 dph, while this effect was not significant at 10 and 30 dph. Levels of IGF-I mRNA also showed a similar tendency, indicating the crucial interaction between IGF-I and somatic growth. The effect of light spectrum on the stress response of turbot larvae was stage specific. At 10 dph, prior to metamorphosis, long wavelengths could induce a stress response in turbot larvae. At 20 dph, metamorphosis began and no significant stress response was observed in larvae exposed to different light spectra; however, LDO significantly up-regulated SOD, CAT, POD and LZM activity. Metamorphosis continued until 56 dph. From 20 to 60 dph long wavelengths (LDR and LDO) resulted in a stress response characterized by high mRNA expression levels of HSP70, GST, CAT, MT, LZM, CTSD and CTSF. SOD, CAT, POD and LZM activities were inhibited, indicating increased enzyme consumption to maintain homeostasis. Overall, our results suggested that LDF should be used in turbot culture systems prior to metamorphosis and LDB should be used after metamorphosis. These findings are in keeping with the changes in light spectra experienced by turbot larvae undergoing metamorphosis in the wild.

Dl-Methionine supplementation in a low-fishmeal diet affects the TOR/S6K pathway by stimulating ASCT2 amino acid transporter and insulin-like growth factor-I in the dorsal muscle of juvenile cobia (Rachycentron canadum).

An 8-week feeding experiment was conducted to investigate the effects of dl-methionine (Met) supplementation in a low-fishmeal diet on growth, key gene expressions of amino acid transporters and target of rapamycin (TOR) pathway in juvenile cobia, Rachycentron canadum. Seven isonitrogenous and isolipidic diets were formulated, containing 0·72, 0·90, 1·00, 1·24, 1·41, 1·63 and 1·86 % Met. Weight gain and specific growth rates increased gradually with Met levels of up to 1·24 % and then decreased gradually. In dorsal muscle, mRNA levels of ASCT2 in the 1·00 % Met group were significantly up-regulated compared with 0·72, 1·63, and 1·86 %. The insulin-like growth factor-I (IGF-I) mRNA levels in the dorsal muscle of fish fed 1·00 and 1·24 % Met were higher than those in fish fed other Met levels. In addition, fish fed 1·24 % Met showed the highest mRNA levels of TOR and phosphorylation of TOR on Ser2448. The phosphorylation of ribosomal p70-S6 kinase (S6K) on Ser371 in the dorsal muscle of fish fed 1·86 % Met was higher than those in the 0·72 % group. In conclusion, straight broken-line analysis of weight gain rate against dietary Met level indicates that the optimal Met requirement for juvenile cobia is 1·24 % (of DM, or 2·71 % dietary protein). Met supplementation in a low-fishmeal diet increased cobia growth via a mechanism that can partly be attributed to Met's ability to affect the TOR/S6K signalling pathway by enhancing ASCT2 and IGF-I transcription in cobia dorsal muscle.

IGF-IEc Expression Is Associated With Advanced Differentiated Thyroid Cancer.

Recent knowledge implicates a differential expression of the insulin-like growth factor-I (IGF-I) mRNA splice variants (i.e., IGF-IEa, IGF-IEb and IGF-IEc) in cancerous tissues, implying possible specific roles of the encoded IGF-I protein isoforms in cancer biology. In particular, there is growing evidence that the IGF-IEc isoform may play a distinct biological role in various types of cancers. The present study investigated whether IGF-IEc expression is associated with a particular type of thyroid cancer. Formalin-fixed paraffin-embedded tissue specimens of different types of thyroid cancers from 92 patients were assessed for IGF-IEc expression by immunohistochemistry. In addition, thyroid cancer biopsies of different TNM staging histological types were evaluated for mRNA expression of the IGF-IEc transcript by real-time polymerase chain reaction (PCR). From the total number of 92 samples, 2 were anaplastic, 10 medullary, 4 hyperplasias of C-cells, 11 follicular, 5 hurtle cell carcinomas, 2 poorly differentiated, 5 nodular hyperplasias, 1 lymphoma and 52 were papillary thyroid cancers. The age of cancer diagnosis or tumor size did not significantly affect the IGF-IEc expression. Among all types of cancers, IGF-IEc was expressed in papillary differentiated thyroid cancer. Its expression/localization was mainly cytoplasmic and significantly associated with TNM staging and the presence of muscular and capsule cancerous invasion (p<0.05). Similarly, a differential profile was revealed regarding the mRNA expression of the IGF-IEc transcript, that exhibited a higher expression in aggressive compared to the non-aggressive papillary cancers. IGF-IEc isoform expression in thyroid cancer is positively associated with more advanced stages of papillary thyroid cancer.

Insulin-Like Growth Factor-I Protects Against the Detrimental Effects of Advanced Glycation End Products and High Glucose in Myoblastic C2C12 Cells.

Previous studies suggested that advanced glycation end products (AGEs) and insulin-like growth factor-I (IGF-I) are involved in the mechanism of diabetes-induced sarcopenia. In this study, we examined effects of treatments with AGEs and/or IGF-I for 24h on myogenic differentiation and apoptosis in mouse myoblastic C2C12 cells. Real-time PCR and Western blot were performed to investigate mRNA and protein expressions, and apoptosis was examined by using a DNA fragment detection ELISA kit. AGE3 significantly decreased mRNA and protein expressions of MyoD and Myogenin, whereas IGF-I significantly increased them and attenuated the effects of AGE3. AGEs significantly decreased endogenous IGF-I mRNA expression and suppressed IGF-I-induced Akt activation. High glucose (22mM) significantly increased mRNA expression of Rage, a receptor for AGEs, while IGF-I significantly decreased it. DNA fragment ELISA showed that AGE2 and AGE3 significantly increased apoptosis of C2C12 cells, whereas IGF-I significantly suppressed the AGE2- and AGE3-induced apoptosis. In contrast, high glucose enhanced AGE3-induced apoptosis. IGF-I significantly attenuated the effects of high glucose plus AGE3 on the mRNA and protein expressions of MyoD and Myogenin as well as the apoptosis. These findings indicate that AGEs inhibit myogenic differentiation and increase apoptosis in C2C12 cells, and that high glucose increases RAGE and enhances the AGE3-induced apoptosis, suggesting that AGEs and high glucose might contribute to the reduction of muscle mass and function. Moreover, IGF-I attenuated the detrimental effects of AGEs and high glucose in myoblastic cells; thus, IGF-I-Akt signal could be a therapeutic target of DM-induced sarcopenia.

INFLUENCE OF STOCKING DENSITY ON GROWTH PERFORMANCE TRAITS, BLOOD CHEMISTRY AND THE EXPRESSION OF HSP70 AND IGF-I GENES IN NEW ZEALAND WHITE RABBITS

This research was done to mainfest the effect of stocking density on growth performance traits, blood chemistry and the expression of heat shock protein (HSP) 70 and insulin-like growth factor I (IGF-I) genes in growing New Zealand White rabbits. A total of 75 rabbits at weaning (35 days of age) were randomly assigned into three stocking densities of 12, 20 and 28 rabbits/m2 from weaning until 13 weeks of age. Rabbits housed at 28 rabbits/m2 had the lowest feed intake, live body weight and body weight gain, but they had the highest feed to gain ratio when compared with the lower densities. Moreover, rabbits housed at 28 rabbits/m2 showed the highest serum creatinine, glucose and cortisol levels compared with rabbits housed at 20 and 12 rabbits/m2. High stocking density up-regulated the expression of HSP70 gene when compared with the lower densities. Meanwhile, IGF-I mRNA expression was significantly reduced in the rabbits housed at 28 rabbits/m2. In conclusion, high stocking densities (28 rabbit/m2) had negative impacts on growth performance traits and the stress-related parameters (serum glucose, cortisol and creatinine). Moreover, the expression of HSP70 gene was increased, with a remarkable reduction in IGF-I gene expression in the high stocking group.

Abstract 5465: Resveratrol inhibits cell proliferation via crosstalk between integrin αvβ3 and IGF-1R in primary cell cultures of human uterine fibroids

Abstract A uterine fibroid is the most common benign smooth muscle cell tumor of the myometrium. Resveratrol, a stilbene, has been used as an anti-inflammatory and antitumor agent. We aimed to determine the expression of growth factor molecules for growth inhibition after treatment of resveratrol in the primary cell lines from human uterine fibroid. In terms of growth rate, of the 24 uterine fibroid primary cell culture cells, 5 were mildly sensitive, 13 were medium-, and 6 were sensitive to resveratrol treatment. 19 out of the 24 primary cell lines responded to treatment of resveratrol from middle to sensitive ranges. Resveratrol arrested cell proliferation and also induced apoptosis, indicating that an intact apoptotic pathway was present in these cells by resveratrol. Reduction of integrin αvβ3 expression diminished resveratrol-induced antiproliferative effect in uterine fibroid cells. Resveratrol induced the expression of proapoptotic genes such as COX-2 and p21. On the other hand, the expression of proliferative (antiapoptotic) genes was either inhibited in such as BCL2 and CDKN2 or not changed in Cyclin D1 and PCNA. The expression of mRNA and protein of insulin-like growth factor-I (IGF-I) was inhibited by resveratrol in primary uterine fibroid cells. The proapoptotic proteins such as caspase 3 and caspase 9 were activated after resveratrol treatment and demonstrated that resveratrol induced apoptosis in the resveratrol-sensitive primary cell cultures, which was consistent with studies of the flow cytometry. In addition, resveratrol blocked the expression of integrin αvβ3 and protein. Concurrently, constitutive AKT phosphorylation in uterine fibroid cells was inhibited by resveratrol. Therefore, growth modulation of uterine fibroid cells occurs via mechanisms dependent on crosstalk between integrin αvβ3 and IGF-1R. Our findings suggest that resveratrol can be considered as an alternative therapeutic agent for uterine fibroid. Citation Format: Yi-Ru Chen, Ya-Jung Shih, Heng-Yuan Tang Tang, Hung-Yun Lin, Paul J. Davis. Resveratrol inhibits cell proliferation via crosstalk between integrin αvβ3 and IGF-1R in primary cell cultures of human uterine fibroids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5465.

Dietary arginine affects growth, gut morphology, oxidation resistance and immunity of hybrid grouper (Epinephelus fuscoguttatus♀×Epinephelus lanceolatus♂) juveniles.

An 8-week growth trial was conducted to evaluate the effects of dietary arginine (Arg) levels on growth, gut morphology, oxidation resistance and immunity of hybrid grouper (Epinephelus fuscoguttatus♀×Epinephelus lanceolatus♂) juveniles. Seven isoenergetic (1465 kJ (350 kcal)/100-g DM), isoproteic (53·5 % of DM) and isolipidic (7 % of DM) experimental diets were formulated to contain graded Arg levels ranging from 1·9 to 4·7 % (dry weight) at approximately 0·5 % increments. Each diet was randomly assigned to triplicate groups of 16 juvenile fish (average initial body weight: 11·7 (sd 0·1) g) and was administered twice daily (08.00 and 16.00 hours). After the growth trial, all remaining fish were fed their prescribed diets for 2 d and then exposed to 4·5 mg Cu2+/l water for 36 h. Results showed that growth performance and feed utilisation of experimental fish were significantly affected by different dietary Arg levels. Weight gain % (WG%) of fish was increased as dietary Arg increased, reaching a peak value at 3·8 % dietary Arg level, and when dietary Arg level increased to 4·7 % WG% was reduced. Fish fed 1·9 and 2·2 % dietary Arg levels had higher daily feed intake compared with fish fed other dietary Arg levels. Feed conversion ratios in fish fed 1·9, 2·2, 2·7 and 4·7 % dietary Arg levels were higher than those in fish fed 3·1, 3·8 and 4·1 % dietary Arg levels. Protein efficiency ratio and protein productive value (PPV) increased with an increase in dietary Arg, up to a peak value at 3·8 % dietary Arg level, above which these parameters declined. On the basis of quadratic regression analysis of weight gain % (WG%) or PPV against dietary Arg levels, the optimal dietary Arg requirement for hybrid grouper was estimated to be 3·65 %. Fish fed 3·8 % dietary Arg had higher whole-body and muscle protein contents compared with fish fed other dietary Arg levels. Fish fed 3·8 and 4·1 % dietary Arg levels had higher levels of mRNA for insulin-like growth factor-I and target of rapamycin in the liver compared with fish fed other dietary Arg levels. Hepatic S6 kinase 1 mRNA expression in fish fed 3·8 % dietary Arg level was higher than that in fish fed any of the other dietary Arg levels. Gut morphology, hepatic antioxidant indices and immune indices in serum and head kidney were significantly influenced by dietary Arg levels. In conclusion, the optimal dietary Arg requirement for hybrid grouper was estimated to be 3·65 %, and suitable dietary Arg supplementations improved gut morphology and oxidation resistance of hybrid grouper.

Activation of IGF-1/IGFBP-3 signaling by berberine improves intestinal mucosal barrier of rats with acute endotoxemia

Insulin-like growth factor I (IGF-I) and binding protein 3 (IGFBP-3) play a role in the maintenance of gut mucosal barrier function. Nevertheless, IGF-I/IGFBP-3 and tight junction protein (TJP) expression in small intestinal mucosa are often impaired during endotoxemia. In this model of acute endotoxemia, the regulatory effect of berberine on IGF-I/IGFBP-3 and TJP expression in ileal mucosa was evaluated. The findings revealed systemic injection of lipopolysaccharide (LPS) suppressed mRNA and protein expression of IGF-I and IGFBP-3, but berberine ameliorated their production. LPS injection inhibited occludin and claudin-1 protein generation, and this inhibitory effect of LPS was abolished by berberine. Inhibition of IGF-I/IGFBP-3 signaling by AG1024 or siRNAs reduced berberine-induced occludin and claudin-1 production. Additionally, GW9662 was found to repress berberine-induced IGF-I/IGFBP-3 expression, indicating of a cross-link between PPARγ and IGF-I/IGFBP-3 axis.

IGF-IEc expression is increased in secondary compared to primary foci in neuroendocrine neoplasms.

Different Insulin-like growth factor-I (IGF-I) mRNA transcripts are produced by alternative splicing and particularly the IGF-IEc isoform has been implicated in the development and/or progression of various types of cancer. In the present study, we examined the potential role of IGF-IEc expression as a new immunohistochemical marker of aggressiveness in neuroendocrine neoplasms (NENs). We utilized immunohistochemical analysis in tissue specimens of 47 patients with NENs, to evaluate the expression of IGF-IEc (%) and Ki-67 proliferation index (%). Specimens from patients with tumors of different tissue origin, of either primary or metastatic lesions and of different grade were examined. Cytoplasmic IGF-IEc staining was found in 23 specimens of NENs or NECs: 10 pancreatic, 4 small bowel, 3 gastric, 1 lung, 1 uterine and 4 poorly differentiated of unknown primary origin. Ki-67 and IGF-IEc expression was positively correlated in all the samples studied (r=0.31, p=0.03). IGF-1Ec expression was more prevalent in specimens originating from metastatic foci with high Ki-67 compared to primary sites with low Ki-67 expression (p=0.036). These findings suggest a possible role of IGF-IEc in NEN tumorigenesis and progression to metastases that could be used as an additional new marker of a more aggressive behavior and a potential drugable target.

Downregulated Translation Initiation Signaling Predisposes Low-Birth-Weight Neonatal Pigs to Slower Rates of Muscle Protein Synthesis.

Low-birth-weight (LBWT) neonates experience restricted muscle growth in their perinatal life. Our aim was to investigate the mechanisms that contribute to slower skeletal muscle growth of LBWT neonatal pigs. Twenty-four 1-day old male LBWT (816 ± 55 g) and normal-birth-weight (NBWT; 1,642 ± 55 g) littermates (n = 12) were euthanized to collect blood and longissimus dorsi (LD) muscle subsamples. Plasma glucose, insulin, and insulin-like growth factor-I (IGF-I) were lower in LBWT compared with NBWT pigs. Muscle IGF-I mRNA expression were lower in LBWT than NBWT pigs. However, IGF-I receptor mRNA and protein abundance was greater in LD of LBWT pigs. Abundance of myostatin and its receptors, and abundance and phosphorylation of smad3 were lower in LBWT LD by comparison with NBWT LD. Abundance of eukaryotic initiation factor (eIF) 4E binding protein 1 and mitogen-activated protein kinase-interacting kinases was lower in muscle of LBWT pigs compared with NBWT siblings, while eIF4E abundance and phosphorylation did not differ between the two groups. Furthermore, phosphorylation of ribosomal protein S6 kinase 1 (S6K1) was less in LBWT muscle, possibly due to lower eIF3e abundance. In addition, abundance and phosphorylation of eIF4G was reduced in LBWT pigs by comparison with NBWT littermates, suggesting translation initiation complex formation is compromised in muscle of LBWT pigs. In conclusion, diminished S6K1 activation and translation initiation signaling are likely the major contributors to impaired muscle growth in LBWT neonatal pigs. The upregulated IGF-I R expression and downregulated myostatin signaling seem to be compensatory responses for the reduction in protein synthesis signaling.

Betaine promotes cell differentiation of human osteoblasts in primary culture

BackgroundBetaine (BET), a component of many foods, is an essential osmolyte and a source of methyl groups; it also shows an antioxidant activity. Moreover, BET stimulates muscle differentiation via insulin like growth factor I (IGF-I). The processes of myogenesis and osteogenesis involve common mechanisms with skeletal muscle cells and osteoblasts sharing the same precursor. Therefore, we have hypothesized that BET might be effective on osteoblast cell differentiation.MethodsThe effect of BET was tested in human osteoblasts (hObs) derived from trabecular bone samples obtained from waste material of orthopedic surgery. Cells were treated with 10 mM BET at 5, 15, 60 min and 3, 6 and 24 h. The possible effects of BET on hObs differentiation were evaluated by real time PCR, western blot and immunofluorescence analysis. Calcium imaging was used to monitor intracellular calcium changes.ResultsReal time PCR results showed that BET stimulated significantly the expression of RUNX2, osterix, bone sialoprotein and osteopontin. Western blot and immunofluorescence confirmed BET stimulation of osteopontin protein synthesis. BET stimulated ERK signaling, key pathway involved in osteoblastogenesis and calcium signaling. BET induced a rise of intracellular calcium by means of the calcium ions influx from the extracellular milieu through the L-type calcium channels and CaMKII signaling activation. A significant rise in IGF-I mRNA at 3 and 6 h and a significant increase of IGF-I protein at 6 and 24 h after BET stimulus was detected. Furthermore, BET was able to increase significantly both SOD2 gene expression and protein content.ConclusionsOur study showed that three signaling pathways, i.e. cytosolic calcium influx, ERK activation and IGF-I production, are enhanced by BET in human osteoblasts. These pathways could have synergistic effects on osteogenic gene expression and protein synthesis, thus potentially leading to enhanced bone formation. Taken together, these results suggest that BET could be a promising nutraceutical therapeutic agent in the strategy to counteract the concomitant and interacting impact of sarcopenia and osteoporosis, i.e. the major determinants of senile frailty and related mortality.