Insulin-like growth factors (IGFs), IGF receptors, and IGF-binding proteins: roles in skeletal muscle growth and differentiation

IGF2 promotes the differentiation of chicken embryonic myoblast by regulating mitochondrial remodeling

Skeletal muscle is crucial for animal movement and posture maintenance, and it serves as a significant source of meat in the livestock and poultry industry. The number of muscle fibers differentiated from myoblast in the embryonic stage is one of the factors determining the content of skeletal muscle. Insulin-like growth factor 2 (IGF2), a well-known growth-promoting hormone, is crucial for embryonic and skeletal muscle growth and development. However, the specific molecular mechanism underlying its impact on chicken embryonic myoblast differentiation remains unclear. To elucidate the molecular mechanism by which IGF2 regulates chicken myoblast differentiation, we manipulated IGF2 expression in chicken embryonic myoblast. The results demonstrated that IGF2 was upregulated during chicken skeletal muscle development and myoblast differentiation. On the one hand, we found that IGF2 promotes mitochondrial biogenesis through the PGC1/NRF1/TFAM pathway, thereby enhancing mitochondrial membrane potential, oxidative phosphorylation, and ATP synthesis during myoblast differentiation. This process is mediated by the PI3K/AKT pathway. On the other hand, IGF2 regulates BNIP3-mediated mitophagy, clearing dysfunctional mitochondria. Collectively, our findings confirmed that IGF2 cooperatively regulates mitochondrial biogenesis and mitophagy to remodel the mitochondrial network and enhance mitochondrial function, ultimately promoting myoblast differentiation.

Disturbance of fetal growth by azithromycin through induction of ER stress in the placenta

AIM

Azithromycin (AZM) is widely used to treat mycoplasma infection in pregnancy. However, there is no adequate evaluation of its side effect on the placenta. Here, by using human placental syncytiotrophoblasts and a mouse model, we investigated whether AZM use in pregnancy might adversely affect placental function and pregnancy outcome.

RESULTS

Transcriptomic analysis of AZM-treated human placental syncytiotrophoblasts showed increased expression of ER stress-related genes and decreased expression of genes for hormone production and growth factor processing. Verification studies showed that AZM increased the abundance of ER stress mediators (phosphorylated eIF2α, ATF4 and CHOP), and decreased the abundance of enzymes involved in progesterone and estradiol synthesis (STS, CYP11A1 and CYP19A1) and IGFBP cleavage (PAPPA and ADAM12) in human placental syncytiotrophoblasts. Inhibition of ER stress blocked AZM-induced decreases in the expression of CYP19A1, CYP11A1, PAPPA and ADAM12, suggesting that the inhibition of AZM on those genes' expression was secondary to AZM-induced ER stress. Further mechanism study showed that increased ATF4 in ER stress might repressively interact with C/EBPα to suppresstheexpression ofthose genes including CEBPAitself. Mouse studies showed that AZM administration decreased fetal weights along with increased ER stress mediators and decreased levels of insulin-like growth factor, estrogen and progesterone in the maternal blood, which could be alleviated by inhibition of ER stress.

INNOVATION AND CONCLUSION

These findings firstly support AZM, often used during pregnancy, may affect fetal growth by inhibiting crucial enzymes for estrogen and progesterone synthesis and disrupting crucial proteases for IGFBP cleavage via inducing ER stress in placental syncytiotrophoblasts.

Implication of Pappalysins and Stanniocalcins in the Bioavailability of IGF-I in Children With Type 1 Diabetes Mellitus

Context

Anomalies in the growth hormone (GH)/insulin-like growth factor (IGF) axis, are common in children with type 1 diabetes mellitus (T1DM), even in those reaching a normal or near-normal final height. However, concentrations of the IGF bioavailability regulatory factors (pappalysins [PAPP-As] and stanniocalcins [STCs]) have not been reported in children with T1DM.

Objective

To determine serum concentrations of PAPP-As and STCs in children at diagnosis of T1DM and after insulin treatment and the correlation of these factors with other members of the GH/IGF axis, beta-cell insulin reserve, auxology, and nutritional status.

Methods

A single-center prospective observational study including 47 patients (59.5% male), with T1DM onset at median age of 9.2 years (interquartile range: 6.3, 11.9) was performed. Blood and anthropometric data were collected at diagnosis and after 6 and 12 months of treatment.

Results

At 6 and 12 months after T1DM diagnosis, there was improvement in the metabolic control (decrease in glycated hemoglobin [HbA1c] at 12 months -3.66 [95% CI: -4.81, -2.05], P = .001), as well as in body mass index SD and height SD (not statistically significant). STC2 increased (P < .001) and PAPP-A2 decreased (P < .001) at 6 and 12 months of treatment onset (P < .001), which was concurrent with increased total IGF-I and IGF-binding protein concentrations, with no significant modification in free IGF-I concentrations. HbA1c correlated with PAPP-A2 (r = +0.41; P < .05) and STC2 (r = -0.32; P < .05).

Conclusion

Implementation of insulin treatment after T1DM onset modifies various components of the circulating IGF system, including PAPP-A2 and STC2. How these modifications modulate linear growth remains unknown.

Exploring the Integrated Role of miRNAs and lncRNAs in Regulating the Transcriptional Response to Amino Acids and Insulin-like Growth Factor 1 in Gilthead Sea Bream (Sparus aurata) Myoblasts

In this study, gilthead sea bream (Sparus aurata) fast muscle myoblasts were stimulated with two pro-growth treatments, amino acids (AA) and insulin-like growth factor 1 (Igf-1), to analyze the transcriptional response of mRNAs, microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) and to explore their possible regulatory network using bioinformatic approaches. AA had a higher impact on transcription (1795 mRNAs changed) compared to Igf-1 (385 mRNAs changed). Both treatments stimulated the transcription of mRNAs related to muscle differentiation (GO:0042692) and sarcomere (GO:0030017), while AA strongly stimulated DNA replication and cell division (GO:0007049). Both pro-growth treatments altered the transcription of over 100 miRNAs, including muscle-specific miRNAs (myomiRs), such as miR-133a/b, miR-206, miR-499, miR-1, and miR-27a. Among 111 detected lncRNAs (>1 FPKM), only 30 were significantly changed by AA and 11 by Igf-1. Eight lncRNAs exhibited strong negative correlations with several mRNAs, suggesting a possible regulation, while 30 lncRNAs showed strong correlations and interactions with several miRNAs, suggesting a role as sponges. This work is the first step in the identification of the ncRNAs network controlling muscle development and growth in gilthead sea bream, pointing out potential regulatory mechanisms in response to pro-growth signals.

Muscle Fiber Characteristics and Transcriptome Analysis in Slow- and Fast-Growing Megalobrama amblycephala

Growth is an important trait in aquaculture that is influenced by various factors, among which genetic regulation plays a crucial role. Megalobrama amblycephala, one of the most important freshwater species in China, exhibits wide variations in body mass among individuals of the same age within the same pool. But the molecular mechanisms underlying wide variation in body mass remain unclear. Here, we performed muscle histological and transcriptome analysis of muscle tissues from Fast-Growing (FG) and Slow-Growing (SG) M. amblycephala at the age of 4 months old (4 mo) and 10 months old (10 mo) to elucidate its muscle development and growth mechanism. The muscle histological analysis showed smaller diameter and higher total number of muscle fibers in FG compared to SG at 4 mo, while larger diameter and total number of muscle fibers were detected in FG at 10 mo. The transcriptome analysis of muscle tissue detected 1171 differentially expressed genes (DEGs) between FG and SG at 4 mo, and 718 DEGs between FG and SG at 10 mo. Furthermore, 44 DEGs were consistently up-regulated in FG at both 4 mo and 10 mo. Up-regulated DEGs in FG at 4 mo were mainly enriched in the pathways related to cell proliferation, while down-regulated DEGs were significantly enriched in cell fusion and muscle contraction. Up-regulated DEGs in FG at 10 mo were mainly enriched in the pathways related to cell proliferation and protein synthesis. Therefore, these results provide novel insights into the molecular mechanism of M. amblycephala muscle growth at different stages, and will be of great guiding significance to promote the fast growth of M. amblycephala.

Maternal protein supplementation during mid-gestation improves offspring performance and metabolism in beef cows

This study examined the impact of maternal protein supplementation during mid-gestation on offspring, considering potential sex-related effects. Forty-three pregnant purebred Tabapuã beef cows (20 female and 23 male fetuses) were collectively managed in a pasture until 100 d of gestation. From 100 to 200 d of gestation, they were randomly assigned to the restricted group [(RES) - basal diet (75% corn silage + 25% sugar cane bagasse + mineral mixture); n = 24] or control group [(CON) - same basal diet + based-plant supplement [40% of crude protein, 3.5 g/kg of body weight (BW); n = 19]. From 200 d of gestation until parturition, all cows were equally fed corn silage and mineral mixture. During the cow-calf phase, cows and their calves were maintained in a pasture area. After weaning, calves were individually housed and evaluated during the backgrounding (255 to 320 d), growing 1 (321 to 381 d), and growing 2 (382 to 445 d) phases. Offspring's blood samples were collected at 210 and 445 d of age. Samples of skeletal muscle tissue were collected through biopsies at 7, 30, and 445 d of age. Muscle tissue samples were subjected to reverse-transcription quantitative polymerase chain reaction analysis. Prenatal treatment and offspring's sex (when pertinent) were considered fixed effects. The significance level was set at 5%. At mid-gestation, cows supplemented with protein reached 98% and 92% of their protein and energy requirements, while nonsupplemented cows attained only 30% and 50% of these requirements, respectively. The RES offspring were lighter at birth (27 vs. 31 kg), weaning (197 vs. 214 kg), and 445 d of age (398 vs. 429 kg) (P ≤ 0.05). The CON calves had greater (P < 0.05) morphometric measurements overall. The CON offspring had ~26% greater muscle fiber area (P ≤ 0.01). There was a trend (P = 0.06) for a greater Mechanistic target of rapamycin kinase mRNA expression in the Longissimus thoracis in the CON group at 7 d of age. The Myogenic differentiation 1 expression was greater (P = 0.02) in RES-females. Upregulation of Carnitine palmitoyltransferase 2 was observed in RES offspring at 445 d (P = 0.04). Expression of Fatty acid binding protein 4 (P < 0.001), Peroxisome proliferator-activated receptor gamma (P < 0.001), and Stearoyl-Coenzyme A desaturase (P < 0.001) was upregulated in CON-females. Therefore, protein supplementation during gestation enhances offspring growth and promotes favorable responses to lipogenesis, particularly in females.

miR136 regulates proliferation and differentiation of small tail han sheep preadipocytes

Low meat performance is the defect of Small Tail Han sheep. Intramuscular fat affects meat quality and largely determined by adipogenesis. In previous study, miR136 was showed one of differentially expressed microRNAs between preadipocytes and mature adipocytes of Small Tail Han sheep but its role in adipogenesis is still not elucidated. Here, we investigated the effect of miR136 on adipogenesis and the underlying mechanism. qPCR data showed that miR136 level increased with preadipocytes proliferation while declined with preadipocytes differentiation. Moreover, miR136 mimics blocked lipid droplet formation, reduced lipid content and triglyceride accumulation while miR136 inhibitor showed the opposite effects, revealing that miR136 promoted preadipocytes proliferation but inhibited preadipocytes differentiation. Bioinformatics and biochemical validation manifested that PPARGC1B was a target of miR136. Furthermore, miR136 mimics decreased PPARγ and C/EBPα expression accompanied by PPARGC1B expression descending. Reverse effects were observed with miR136 inhibitor. Besides, overexpression of miR136 elevated IGF1 expression. Collectively, our data first exhibited a regulatory role of miR136 in adipogenesis, which is promoting preadipocytes proliferation through elevating IGF1 expression while inhibiting preadipocytes differentiation through targeting PPARGC1B and further declined PPARγ and C/EBPα expression. The modulation of PPARGC1B by miR136 may provide a new potential target for increasing intramuscular fat.

Low-dose exercise protects the heart against established myocardial infarction via IGF-1-upregulated CTRP9 in male mice

Regular exercise is recommended as an important component of therapy for cardiovascular diseases in clinical practice. However, there are still major challenges in prescribing an optimized exercise regimen to individual patients with established cardiac disease. Here, we tested the effects of different exercise doses on cardiac function in mice with established myocardial infarction (MI). Exercise was introduced to mice with MI after 4 weeks of surgery. Low-dose exercise (15 min/day for 8 weeks) improved mortality and cardiac function by increasing 44.39% of ejection fractions while inhibiting fibrosis by decreasing 37.74% of distant region. Unlike higher doses of exercise, low-dose exercise consecutively upregulated cardiac expression of C1q complement/tumor necrosis factor-associated protein 9 (CTRP9) during exercise (>1.5-fold). Cardiac-specific knockdown of CTRP9 abolished the protective effects of low-dose exercise against established MI, while cardiac-specific overexpression of CTRP9 protected the heart against established MI. Mechanistically, low-dose exercise upregulated the transcription factor nuclear receptor subfamily 2 group F member 2 by increasing circulating insulin-like growth factor 1 (IGF-1), therefore, upregulating cardiac CTRP9 expression. These results suggest that low-dose exercise protects the heart against established MI via IGF-1-upregulated CTRP9 and may contribute to the development of optimized exercise prescriptions for patients with MI.

Identification of the Kupffer cell-derived circulating IGFBP-3 as a universal radiation biomarker for heavy ion, proton, and X-ray exposure

The minimally invasive biomarkers that can facilitate a rapid dose assessment are valuable for the early medical treatment when accidental or occupational radiation exposure happens. Our previous proteomic research identified one kind of circulating protein, Insulin-like Growth Factor Binding Protein 3 (IGFBP-3), which showed a significant increase after total body exposure of mice to carbon ions and X-rays. However, several critical issues such as the responses to diverse radiation, the origin and underlying mechanism in radiation response obstruct the utilization of circulating IGFBP-3 as a reliable radiation biomarker. In this study, mice were subjected to total or partial body irradiation with carbon ions, protons or X-rays, or treated with chloroform as a comparison. The level of IGFBP-3 in serum and different organs were measured via Enzyme Linked Immunosorbent Assay (ELISA), Western blot (WB) and Immunohistochemistry (IHC). A significant increase of IGFBP-3 was discovered in serum and liver tissue post-irradiation with three kinds of radiation, but absent when challenged with chloroform. Likewise, a similar response was also observed in blood samples from patients receiving radiotherapy. Moreover, the effect of radiation on three main hepatic cells was investigated, the findings indicated that IGFBP-3 could be detected in the culture medium of Kupffer cells (MKC) alone and was elevated in cells and cultured medium of MKC post-irradiation. Additionally, we observed a co-expression effect between P53 and IGFBP-3 in liver tissues and MKC post-irradiation. Along with down-regulation of Trp53 by siRNA, the response of IGFBP-3 to radiation was attenuated. The present study demonstrated that circulating IGFBP-3 could be a promising universal biomarker for complex environmental radiation exposure, and the upregulation of IGFBP-3 is attributed to the MKC in a P53-dependent manner. Circulating IGFBP-3 assays would offer rapid, convenient and effective dose and toxicity assessment methods in occupational exposure or radiation disaster management.

Detection of synthetic analogues of insulin-like growth factor 1 in different biological fluids by liquid chromatography quadrupole time-of-flight mass spectrometry: comparison of different immunoaffinity protocols

Insulin-like growth factor 1 analogues are prohibited in sport for their ability to enhance athletic performance in several sport disciplines. Their detection presents several analytical challenges, mainly due to the minimum required performance limits fixed by the World Anti-Doping Agency. Here, we are presenting analytical workflows to detect IGF-1 and its analogues in different biological matrices. Several off-line immunocapture techniques and protocols were comparatively evaluated. Separation and detection were performed by using standard flow reverse-phase liquid chromatography coupled to a time-of-flight mass spectrometer. The best recoveries were obtained using magnetic beads or pipette tips functionalized with protein A. The analytical workflows were fully validated for qualitative determinations: all the target analytes were clearly distinguishable from the interference of the matrices, with limits of detection and identification in the range of 0.05-0.30 ng/mL in urine and 0.5-2.0 ng/mL in serum/plasma. The extraction efficiency proved to be repeatable (CV% < 10) with recoveries higher than 50%. Intra- and inter-day precision were found to be smaller than 10 and 15%, respectively. The method was successfully applied to the analysis of authentic matrix samples containing the target peptides at the minimum required performance limits, proving that the method developed can be successfully applied to detect and identify IGF-1 analogues for doping control purposes in all the matrices selected. The analytical workflow developed here to detect the target peptides in different matrices can be readily implemented in anti-doping laboratories and has the potential to be adapted for the simultaneous analysis of different similarly sized peptide hormones of doping relevance.

Blocking insulin-like growth factor 1 receptor signaling pathway inhibits neuromuscular junction regeneration after botulinum toxin-A treatment

Botulinum toxin-A (BTX) administration into muscle is an established treatment for conditions with excessive muscle contraction. However, botulinum therapy has short-term effectiveness, and high-dose injection of BTX could induce neutralizing antibodies against BTX. Therefore, prolonging its effects could be beneficial in a clinical situation. Insulin-like growth factor-1 receptor (IGF1R) and its ligands, insulin-like growth factor (IGF) -I and II, regulate the physiological and pathological processes of the nervous system. It has been suggested that IGF1R is involved in the process after BTX administration, but the specific regeneration mechanism remains unclear. Therefore, this study aimed to determine how inhibition of IGF1R signaling pathway affects BTX-induced muscle paralysis. The results showed that anti-IGF1R antibody administration inhibited the recovery from BTX-induced neurogenic paralysis, and the synaptic components at the neuromuscular junction (NMJ), mainly post-synaptic components, were significantly affected by the antibody. In addition, the wet weight or frequency distribution of the cross-sectional area of the muscle fibers was regulated by IGF1R, and sequential antibody administration following BTX treatment increased the number of Pax7+-satellite cells in the gastrocnemius (GC) muscle, independent of NMJ recovery. Moreover, BTX treatment upregulated mammalian target of rapamycin (mTOR)/S6 kinase signaling pathway, HDAC4, Myog, Fbxo32/MAFbx/Atrogin-1 pathway, and transcription of synaptic components, but not autophagy. Finally, IGF1R inhibition affected only mTOR/S6 kinase translational signaling in the GC muscle. In conclusion, the IGF1R signaling pathway is critical for NMJ regeneration via specific translational signals. IGF1R inhibition could be highly beneficial in clinical practice by decreasing the number of injections and total dose of BTX due to the prolonged duration of the effect.

Time-Dependent Changes in Muscle IGF1-IGFBP5-PAPP System after Sciatic Denervation

Denervation-induced muscle atrophy is a frequent cause of skeletal muscle diseases. However, the role of the most important muscle growth factor, insulin-like growth factor (IGF-1), in this process is poorly understood. IGF-1 activity is controlled by six IGF-1 binding proteins (IGFBPs). In skeletal muscle, IGFBP-5 seems to have an important role in atrophic processes. Furthermore, pappalysins (PAPP-A) modulate muscle growth by increasing IGF-1 bioavailability through IGFBP cleavage. We aimed to study the time-dependent changes in the IGF1-IGFBP5-PAPP system and its regulators in gastrocnemius muscle after sciatic denervation. Gastrocnemius atrophy and overexpression of IGF-1 was observed from day 3 post-denervation. The proteolytic factors measured were elevated from day 1 post-denervation onwards. Expression of both IGFBP-5 and pappalysins were increased on days 1 and 3. Subsequently, on days 7 to 14 pappalysins returned to control levels while IGFBP-5 remained elevated. The ratio IGFBP-5/PAPP-A was correlated with the main proteolytic markers. All data suggest that the initial increase of pappalysins could facilitate the IGF-1 action on muscle growth, whereas their subsequent decrease could lead to further muscle wasting.

Cysteamine improves growth and the GH/IGF axis in gilthead sea bream (Sparus aurata): in vivo and in vitro approaches

Aquaculture is the fastest-growing food production sector and nowadays provides more food than extractive fishing. Studies focused on the understanding of how teleost growth is regulated are essential to improve fish production. Cysteamine (CSH) is a novel feed additive that can improve growth through the modulation of the GH/IGF axis; however, the underlying mechanisms and the interaction between tissues are not well understood. This study aimed to investigate the effects of CSH inclusion in diets at 1.65 g/kg of feed for 9 weeks and 1.65 g/kg or 3.3 g/kg for 9 weeks more, on growth performance and the GH/IGF-1 axis in plasma, liver, stomach, and white muscle in gilthead sea bream (Sparus aurata) fingerlings (1.8 ± 0.03 g) and juveniles (14.46 ± 0.68 g). Additionally, the effects of CSH stimulation in primary cultured muscle cells for 4 days on cell viability and GH/IGF axis relative gene expression were evaluated. Results showed that CSH-1.65 improved growth performance by 16% and 26.7% after 9 and 18 weeks, respectively, while CSH-3.3 improved 32.3% after 18 weeks compared to control diet (0 g/kg). However, no significant differences were found between both experimental doses. CSH reduced the plasma levels of GH after 18 weeks and increased the IGF-1 ones after 9 and 18 weeks. Gene expression analysis revealed a significant upregulation of the ghr-1, different igf-1 splice variants, igf-2 and the downregulation of the igf-1ra and b, depending on the tissue and dose. Myocytes stimulated with 200 µM of CSH showed higher cell viability and mRNA levels of ghr1, igf-1b, igf-2 and igf-1rb compared to control (0 µM) in a similar way to white muscle. Overall, CSH improves growth and modulates the GH/IGF-1 axis in vivo and in vitro toward an anabolic status through different synergic ways, revealing CSH as a feasible candidate to be included in fish feed.

IGF-1 Therapy Improves Muscle Size and Function in Experimental Peripheral Arterial Disease

Lower-extremity peripheral arterial disease (PAD) has increased in prevalence, yet therapeutic development has remained stagnant. Skeletal muscle health and function has been strongly linked to quality of life and medical outcomes in patients with PAD. Using a rodent model of PAD, this study demonstrates that treatment of the ischemic limb with insulin-like growth factor (IGF)-1 significantly increases muscle size and strength without improving limb hemodynamics. Interestingly, the effect size of IGF1 therapy was larger in female mice than in male mice, highlighting the need to carefully examine sex-dependent effects in experimental PAD therapies.

Influences of l-ascorbic acid on cytotoxic, biochemical, and genotoxic damages caused by copper II oxide nanoparticles in the rainbow trout gonad cells-2

In parallel with the raising use of copper oxide nanoparticles (CuO NPs) in various industrial and commercial practices, scientific reports on their release to the environment and toxicity are increasing. The toxicity of CuO NPs is mostly based on their oxidative stress. Therefore, it is necessary to investigate the efficacy of well-known therapeutic agents as antioxidants against CuO NPs damage. This study aimed to investigate the mechanism of this damage and to display whether l-ascorbic acid could preserve against the cell toxicities induced by CuO NPs in the rainbow trout gonad cells-2 (RTG-2). While CuO NPs treatment significantly diminished cell viability, the l-ascorbic acid supplement reversed this. l-ascorbic acid treatment reversed the changes in expressions of sod1, sod2, gpx1a, and gpx4b genes while playing a supportive role in the changes in the expression of the cat gene induced by CuO NPs treatment. Moreover, CuO NPs treatment caused an upregulation in the expressions of growth-related genes (gh1, igf1, and igf2) and l-ascorbic acid treatment further increased these effects. CuO NPs treatment significantly up-regulated the expression of the gapdh gene (glycolytic enzyme gene) compared to the control group, and l-ascorbic acid treatment significantly down-regulated the expression of the gapdh gene compared to CuO NPs treatment. The genotoxicity test demonstrated that l-ascorbic acid treatment increased the genotoxic effect caused by CuO NPs by acting as a co-mutagen. Based on the findings, l-ascorbic acid has the potential to be sometimes inhibitory and sometimes supportive of cellular mechanisms caused by CuO NPs.

RNA sequencing analysis of the longissimus dorsi to identify candidate genes underlying the intramuscular fat content in Anqing Six-end-white pigs

Intramuscular fat (IMF) is a significant marker for pork quality. The Anqing Six-end-white pig has the characteristics of high meat quality and IMF content. Owing to the influence of European commercial pigs and a late start in resource conservation, the IMF content within local populations varies between individuals. This study analyzed the longissimus dorsi transcriptome of purebred Anqing Six-end-white pigs with varying IMF content to recognize differentially expressed genes. We identified 1528 differentially expressed genes between the pigs with high (H) and low (L) IMF content. Based on these data, 1775 Gene Ontology terms were significantly enriched, including lipid metabolism, modification and storage, and regulation of lipid biosynthesis. Pathway analysis revealed 79 significantly enriched pathways, including the Peroxisome proliferator-activated receptor and mitogen-activated protein kinase signaling pathways. Moreover, gene set enrichment analysis indicated that the L group had increased the expression of genes related to ribosome function. Additionally, the protein-protein interaction network analyses revealed that VEGFA, KDR, LEP, IRS1, IGF1R, FLT1 and FLT4 were promising candidate genes associated with the IMF content. Our study identified the candidate genes and pathways involved in IMF deposition and lipid metabolism and provides data for developing local pig germplasm resources.

Non-synonymous variation and protein structure of candidate genes associated with selection in farm and wild populations of turbot (Scophthalmus maximus)

Non-synonymous variation (NSV) of protein coding genes represents raw material for selection to improve adaptation to the diverse environmental scenarios in wild and livestock populations. Many aquatic species face variations in temperature, salinity and biological factors throughout their distribution range that is reflected by the presence of allelic clines or local adaptation. The turbot (Scophthalmus maximus) is a flatfish of great commercial value with a flourishing aquaculture which has promoted the development of genomic resources. In this study, we developed the first atlas of NSVs in the turbot genome by resequencing 10 individuals from Northeast Atlantic Ocean. More than 50,000 NSVs where detected in the ~ 21,500 coding genes of the turbot genome, and we selected 18 NSVs to be genotyped using a single Mass ARRAY multiplex on 13 wild populations and three turbot farms. We detected signals of divergent selection on several genes related to growth, circadian rhythms, osmoregulation and oxygen binding in the different scenarios evaluated. Furthermore, we explored the impact of NSVs identified on the 3D structure and functional relationship of the correspondent proteins. In summary, our study provides a strategy to identify NSVs in species with consistently annotated and assembled genomes to ascertain their role in adaptation.

Muscle regeneration in gilthead sea bream: Implications of endocrine and local regulatory factors and the crosstalk with bone

Fish muscle regeneration is still a poorly known process. In the present study, an injury was done into the left anterior epaxial skeletal muscle of seventy 15 g gilthead sea bream (Sparus aurata) juveniles to evaluate at days 0, 1, 2, 4, 8, 16 and 30 post-wound, the expression of several muscle genes. Moreover, transcripts' expression in the bone (uninjured tissue) was also analyzed. Histology of the muscle showed the presence of dead tissue the first day after injury and how the damaged fibers were removed and replaced by new muscle fibers by day 16 that kept growing up to day 30. Gene expression results showed in muscle an early upregulation of igf-2 and a downregulation of ghr-1 and igf-1. Proteolytic systems expression increased with capn2 and ctsl peaking at 1 and 2 days post-injury, respectively and mafbx at day 8. A pattern of expression that fitted well with active myogenesis progression 16 days after the injury was then observed, with the recovery of igf-1, pax7, cmet, and cav1 expression; and later on, that of cav3 as well. Furthermore, the first days post-injury, the cytokines il-6 and il-15 were also upregulated confirming the tissue inflammation, while tnfα was only upregulated at days 16 and 30 to induce satellite cells recruitment; overall suggesting a possible role for these molecules as myokines. The results of the bone transcripts showed an upregulation first, of bmp2 and ctsk at days 1 and 2, respectively; then, ogn1 and ocn peaked at day 4 in parallel to mstn2 downregulation, and runx2 and ogn2 increased after 8 days of muscle injury, suggesting a possible tissue crosstalk during the regenerative process. Overall, the present model allows studying the sequential involvement of different regulatory molecules during muscle regeneration, as well as the potential relationship between muscle and other tissues such as bone to control musculoskeletal development and growth, pointing out an interesting new line of research in this group of vertebrates.

Growth regulation in brook charr Salvelinus fontinalis

Fish growth can be modulated through genetic selection. However, it is not known whether growth regulatory mechanisms modulated by genetic selection can provide information about phenotypic growth variations among families or populations. Following a five-generation breeding program that selected for the absence of early sexual maturity and increased growth in brook charr we aimed to understand how the genetic selection process modifies the growth regulatory pathway of brook charr at the molecular level. To achieve this, we studied the regulation of growth traits at three different levels: 1) between lines-one under selection, the other not, 2) among-families expressing differences in average growth phenotypes, which we termed family performance, and 3) among individuals within families that expressed extreme growth phenotypes, which we termed slow- and fast-growing. At age 1+, individuals from four of the highest performing and four of the lowest performing families in terms of growth were sampled in both the control and selected lines. The gene expression levels of three reference and ten target genes were analyzed by real-time PCR. Results showed that better growth performance (in terms of weight and length at age) in the selected line was associated with an upregulation in the expression of genes involved in the growth hormone (GH)/insulin growth factor-1 (IGF-1) axis, including the igf-1 receptor in pituitary; the gh-1 receptor and igf-1 in liver; and ghr and igf-1r in white muscle. When looking at gene expression within families, family performance and individual phenotypes were associated with upregulations of the leptin receptor and neuropeptid Y-genes related to appetite regulation-in the slower-growing phenotypes. However, other genes related to appetite (ghrelin, somatostatin) or involved in muscle growth (myosin heavy chain, myogenin) were not differentially expressed. This study highlights how transcriptomics may improve our understanding of the roles of different key endocrine steps that regulate physiological performance. Large variations in growth still exist in the selected line, indicating that the full genetic selection potential has not been reached.

The maternal energetic environment affects both egg and offspring phenotypes in green anole lizards (Anolis carolinensis)

Animals exist in dynamic environments that may affect both their own fitness and that of their offspring. Maternal effects might allow mothers to prepare their offspring for the environment in which they will be born via several mechanisms, not all of which are well understood. Resource scarcity and forced resource allocation are two scenarios that could affect maternal investment by altering the amount and type of resources available for investment in offspring, albeit in potentially different ways. We tested the hypothesis that maternal dietary restriction and sprint training have different consequences for the offspring phenotype in an oviparous lizard (Anolis carolinensis). To do this, we collected and reared eggs from adult diet-manipulated females (low-diet [LD] or high-diet [HD]) and sprint-trained females (sprint trained [ST] or untrained [UT]) and measured both egg characteristics and hatchling morphology. ST and LD mothers laid both the fewest and heaviest eggs, and ST, UT, and LD eggs also had significantly longer incubation periods than the HD group. Hatchlings from the diet experiment (LD and HD offspring) were the heaviest overall. Furthermore, both body mass of the mother at oviposition and change in maternal body mass over the course of the experiment had significant and sometimes different effects on egg and offspring phenotypes, highlighting the importance of maternal energetic state to the allocation of maternal resources.

The effect of environmental stressors on growth in fish and its endocrine control

Fish body growth is a trait of major importance for individual survival and reproduction. It has implications in population, ecology, and evolution. Somatic growth is controlled by the GH/IGF endocrine axis and is influenced by nutrition, feeding, and reproductive-regulating hormones as well as abiotic factors such as temperature, oxygen levels, and salinity. Global climate change and anthropogenic pollutants will modify environmental conditions affecting directly or indirectly fish growth performance. In the present review, we offer an overview of somatic growth and its interplay with the feeding regulatory axis and summarize the effects of global warming and the main anthropogenic pollutants on these endocrine axes.

Rationed and satiated growth hormone transgenic Coho Salmon (Oncorhynchus kisutch) show tissue specific differences in energy stores

Growth hormone transgenic coho salmon experience increased growth rates, driven primarily through elevated feed intake and feed conversion. However, neuropeptides that signal appetite stimulation have been shown to exhibit variable responses across fed states, suggesting a more complex system mediating growth in these fish. Studies have proposed that growth hormone may have a modulatory role on the energy reserves of fish, possibly through AMP-activated protein kinase (AMPK) activation. AMPK, an energy sensor in cells, has previously been shown to be upregulated in growth hormone transgenic salmon when compared to wild type, however, whether this effect is seen across fed states is unknown. Here, we tested the hypothesis that growth hormone induces an energetic deficit in metabolic tissues, leading to constitutive AMPK activation in growth hormone transgenic salmon. This study compared AMPK activity, ATP, and glycogen, of the liver, heart, and muscle of wild-type, and growth hormone transgenic salmon either fed to satiation or a wild-type ration. The results suggest that white muscle ATP levels in growth hormone salmon are elevated in satiation and rationed conditions. In the liver, growth hormone transgenic salmon fed a rationed wild-type diet experience reductions in ATP level and glycogen. In none of the tissues examined, did AMPK activity change. Taken together, these results indicate that growth hormone transgenic salmon experience metabolic duress when not fed to satiation.

Identification of Key Genes and Biological Pathways Associated with Skeletal Muscle Maturation and Hypertrophy in Bos taurus, Ovis aries, and Sus scrofa

The aim of the current study was to identify the major genes and pathways involved in the process of hypertrophy and skeletal muscle maturation that is common for Bos taurus, Ovis aries, and Sus scrofa species. Gene expression profiles related to Bos taurus, Ovis aries, and Sus scrofa muscle, with accession numbers GSE44030, GSE23563, and GSE38518, respectively, were downloaded from the GEO database. Differentially expressed genes (DEGs) were screened out using the Limma package of R software. Genes with Fold Change > 2 and an adjusted p-value < 0.05 were identified as significantly different between two treatments in each species. Subsequently, gene ontology and pathway enrichment analyses were performed. Moreover, hub genes were detected by creating a protein−protein interaction network (PPI). The results of the analysis in Bos taurus showed that in the period of 280 dpc−3-months old, a total of 1839 genes showed a significant difference. In Ovis aries, however, during the period of 135dpc−2-months old, a total of 486 genes were significantly different. Additionally, in the 91 dpc−adult period, a total of 2949 genes were significantly different in Sus scrofa. The results of the KEGG pathway enrichment analysis and GO function annotation in each species separately revealed that in Bos taurus, DEGs were mainly enriched through skeletal muscle fiber development and skeletal muscle contraction, and the positive regulation of fibroblast proliferation, positive regulation of skeletal muscle fiber development, PPAR signaling pathway, and HIF-1 signaling pathway. In Ovis aries, DEGs were mainly enriched through regulating cell growth, skeletal muscle fiber development, the positive regulation of fibroblast proliferation, skeletal muscle cell differentiation, and the PI3K-Akt signaling, HIF-1 signaling, and Rap1 signaling pathways. In Sus scrofa, DEGs were mainly enriched through regulating striated muscle tissue development, the negative regulation of fibroblast proliferation and myoblast differentiation, and the HIF-1 signaling, AMPK signaling, and PI3K-Akt signaling pathways. Using a Venn diagram, 36 common DEGs were identified between Bos taurus, Ovis aries, and Sus scrofa. A biological pathways analysis of 36 common DEGs in Bos taurus, Ovis aries, and Sus scrofa allowed for the identification of common pathways/biological processes, such as myoblast differentiation, the regulation of muscle cell differentiation, and positive regulation of skeletal muscle fiber development, that orchestrated the development and maturation of skeletal muscle. As a result, hub genes were identified, including PPARGC1A, MYOD1, EPAS1, IGF2, CXCR4, and APOA1, in all examined species. This study provided a better understanding of the relationships between genes and their biological pathways in the skeletal muscle maturation process.

Potential Role of Insulin-Like Growth Factors in Myofascial Pain Syndrome: A Narrative Review

ABSTRACT

Insulin-like growth factors have diverse functions in skeletal muscles by acting through multiple signaling pathways, including growth regulation and differentiation, anti-inflammation, and antioxidation. Insulin-like growth factors have anti-inflammatory effects and also play roles in nociceptive pathways, determining pain sensitivity, in addition to their protective role against ischemic injury in both the nervous system and skeletal muscle. In skeletal muscle, insulin-like growth factors maintain homeostasis, playing key roles in maintenance, accelerating muscle regeneration, and repair processes. As part of their maintenance role, increased levels of insulin-like growth factors may be required for the repair mechanisms after exercise. Although the role of insulin-like growth factors in myofascial pain syndrome is not completely understood, there is evidence from a recent study that insulin-like growth factor 2 levels in patients with myofascial pain syndrome are lower than those of healthy individuals and are associated with increased levels of inflammatory biomarkers. Importantly, higher insulin-like growth factor 2 levels are associated with increased pain severity in myofascial pain syndrome patients. This may suggest that too low or high insulin-like growth factor levels may contribute to musculoskeletal disorder process, whereas a midrange levels may optimize healing without contributing to pain hypersensitivity. Future studies are required to address the mechanisms of insulin-like growth factor 2 in myofascial pain syndrome and the optimal level as a therapeutic agent.

Sex-specific responses to growth hormone and luteinizing hormone in a model teleost, the Mozambique tilapia

Across the vertebrate lineage, sexual dimorphism in body size is a common phenomenon that results from trade-offs between growth and reproduction. To address how key hormones that regulate growth and reproduction interact in teleost fishes, we studied Mozambique tilapia (Oreochromis mossambicus) to determine whether the activities of luteinizing hormone (Lh) are modulated by growth hormone (Gh), and conversely, whether targets of Gh are affected by the presence of Lh. In particular, we examined how gonadal morphology and specific gene transcripts responded to ovine GH (oGH) and/or LH (oLH) in hypophysectomized male and female tilapia. Hypophysectomized females exhibited a diminished gonadosomatic index (GSI) concomitant with ovarian follicular atresia. The combination of oGH and oLH restored GSI and ovarian morphology to conditions observed in sham-operated controls. A similar pattern was observed for GSI in males. In control fish, gonadal gh receptor (ghr2) and estrogen receptor β (erβ) expression was higher in females versus males. A combination of oGH and oLH restored erβ and arβ in females. In males, testicular insulin-like growth factor 3 (igf3) expression was reduced following hypophysectomy and subsequently restored to control levels by either oGH or oLH. By contrast, the combination of both hormones was required to recover ovarian igf3 expression in females. In muscle, ghr2 expression was more responsive to oGH in males versus females. In the liver of hypophysectomized males, igf2 expression was diminished by both oGH and oLH; there was no effect of hypophysectomy, oGH, or oLH on igf2 expression in females. Collectively, our results indicate that gene transcripts associated with growth and reproduction exhibit sex-specific responses to oGH and oLH. These responses reflect, at least in part, how hormones mediate trade-offs between growth and reproduction, and thus sexual dimorphism, in teleost fishes.

Blood flow restriction training promotes functional recovery of knee joint in patients after arthroscopic partial meniscectomy: A randomized clinical trial

Purpose: To explore the effect of blood flow restriction training (BFRT) on the recovery of knee function in patients after arthroscopic partial meniscectomy (APM).

Methods: Forty patients undergoing APM surgery were included in this parallel group, two-arm, single-assessor blinded, randomized clinical trial. The subjects were randomly divided into two groups: routine rehabilitation group (RR Group, n = 20) and routine rehabilitation + blood flow restriction training group (RR + BFRT Group, n = 20). One subject in each group dropped out during the experiment. All patients received 8 weeks of routine rehabilitation starting from the second day after APM. In addition, patients in the RR + BFRT group required additional BFRT twice a week. Visual analogue scale (VAS) score, range of motion (ROM), one-leg standing test (OLST) score, Lysholm knee score, quadriceps muscle strength, quadriceps thickness, and thigh circumference were evaluated at preoperative, postoperative, 4 and 8 weeks after surgery. SPSS 25.0 software was used for statistical analysis of the data. Repeated measures ANOVA was used if the data were normally distributed and had homogeneity of variance. Generalized estimating equations were chosen if the data were not normally distributed or had homogeneity of variance.

Results: There were no significant differences in VAS score, ROM, OLST score, Lysholm knee score, quadriceps muscle strength, quadriceps thickness, and thigh circumference between the two groups before surgery (p > 0.05). Compared with postoperative, VAS score, ROM, OLST score, Lysholm knee score, and thigh circumference were significantly improved in the RR group (p < 0.05), while quadriceps muscle strength and quadriceps thickness were not significantly enhanced at 8 weeks postoperatively (p > 0.05). However, VAS score, ROM, OLST score, Lysholm knee score, quadriceps muscle strength, quadriceps thickness, and thigh circumference were all significantly improved in the RR + BFRT group at 8 weeks postoperatively (p < 0.05). Furthermore, compared with the RR group, VAS score (50% vs. 86%), ROM (7.9% vs. 16.0%), OLST score (57.3% vs. 130.1%), Lysholm knee score (38.4% vs. 55.7%), relative peak torque (11.0% vs. 84.7%), mean power (20.6% vs. 88.1%), rectus femoris thickness (0.40% vs. 13.0%), vastus medialis (0.29% vs. 5.32%), vastus lateralis (0% vs. 6.2%), vastus internus (0% vs. 5.8%), and thigh circumference (2.7% vs. 5.8%) in the RR + BFRT group were significantly improved at 4 and 8 weeks postoperatively (p < 0.05).

Conclusion: BFRT combined with routine rehabilitation training can better promote the recovery of knee joint function in patients after APM, especially the improvement of quadriceps muscle strength and thickness.

Hydroxytyrosol-rich extract from olive juice as an additive in gilthead sea bream juveniles fed a high-fat diet: Regulation of somatic growth

The dietary inclusion of plant-based products in fish feeds formulation is required for the sustainable development of aquaculture. Moreover, considering functional diets, hydroxytyrosol, one of the major phenolic compounds found in olives (Olea europaea), has been identified as a potential candidate to be used in the aquafeeds industry due to its health promoting abilities. The aim of this study was to evaluate the effects of the inclusion of an olive juice extract rich in hydroxytyrosol as an additive (0.52 g HT/kg feed) in a high-fat (24% lipids) diet in gilthead sea bream (Sparus aurata) juveniles. Moreover, the experimental diets, with or without the extract, were administered daily at a standard (3% of total biomass in the tank) or restricted ration (40% reduction) for 8–9 weeks. Growth and biometric parameters, insulin-like growth factor 1 (IGF-1) plasma levels and growth hormone/IGF axis-, myogenic- and osteogenic-related genes expression in liver, white muscle and/or bone were analyzed. Moreover, in vitro cultures of vertebra bone-derived cells from fish fed the diets at a standard ration were performed at weeks 3 and 9 to explore the effects of hydroxytyrosol on osteoblasts development. Although neither body weight or any other biometric parameter were affected by diet composition after 4 or 8 weeks, the addition of the hydroxytyrosol-rich extract to the diet increased IGF-1 plasma levels, regardless of the ration regime, suggesting an anabolic condition. In muscle, the higher mRNA levels of the binding protein igfbp-5b and the myoblast fusion marker dock5 in fish fed with the hydroxytyrosol-rich diet suggested that this compound may have a role in muscle, inducing development and a better muscular condition. Furthermore in bone, increased osteogenic potential while delayed matrix mineralization after addition to the diet of the olive juice extract was supported by the upregulated expression of igf-1 and bmp4 and reduced transcript levels of osteopontin. Overall, this study provides new insights into the beneficial use of hydroxytyrosol as a dietary additive in gilthead sea bream functional diets to improve muscle-skeletal condition and, the aquaculture industry.

Dietary effects of aucubin on growth and flesh quality of grass carp (Ctenopharyngodon idellus) based on metabolomics

This aim of this study was to investigate the effects of dietary aucubin on the growth, flesh quality, and metabolomics of grass carp (Ctenopharyngodon idella). Five diets were designed with the aucubin inclusion of 0 (control diet), 0.2, 0.4, 0.6, and 0.8 g/kg (Auc-0.2, Auc-0.4, Auc-0.6, Auc-0.8) and were fed to grass carp with an initial body weight of 17.0 ± 0.2 g for 60 d. The results indicated that dietary aucubin did not significantly affect the growth performance of grass carp (P > 0.05). Compared to the control, dietary supplementation with 0.2 to 0.8 g/kg aucubin increased flesh hardness, chewiness, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and the contents of total free amino acids (TFAA) and n-3 polyunsaturated fatty acids (n-3 PUFA) (P < 0.05). The contents of malondialdehyde (MDA) and lactic acid (LD) in the flesh were significantly decreased by the addition of 0.4 to 0.6 g/kg aucubin and by the addition of 0.6 to 0.8 g/kg aucubin (P < 0.05), respectively, while the content of delicious amino acids (DAA) was significantly enhanced by the addition of 0.4 to 0.8 g/kg aucubin (P < 0.05). Moreover, the contents of collagen and C22:6n3 (DHA) in the flesh of the Auc-0.8 group were significantly higher than those of the control (P < 0.05). In the metabolomics profiling of flesh, 133 and 135 named differential metabolites were identified in the Auc-0.4 and Auc-0.8 groups, respectively, compared to the control, and these metabolites were found to be involved in the second-grade pathways of "lipid metabolism" and "amino acid metabolism". Regarding gene expression, the mRNA levels of CuZn-SOD, CAT, COL1A1, COL1A2, Smad4, and FAS in flesh were upregulated in the Auc-0.4 and Auc-0.8 groups, and the expression levels of GPx, Nrf2, and TGF-β1 mRNA were also upregulated in the Auc-0.8 group (P < 0.05). In summary, dietary aucubin did not promote growth, but improved the flesh quality of grass carp, which might be associated with the TGF-β/Smad and Nrf2 pathways. The recommended supplementation level of aucubin in the diet of grass carp was 0.6 to 0.8 g/kg.

Sprint training interacts with body mass to affect hepatic insulin-like growth factor expression in female green anoles (Anolis carolinensis)

Locomotor performance is a key predictor of fitness in many animal species. As such, locomotion integrates the output of a number of morphological, physiological, and molecular levels of organization, yet relatively little is known regarding the major molecular pathways that bolster locomotor performance. One potentially relevant pathway is the insulin and insulin-like signaling (IIS) network, a significant regulator of physiological processes such as reproduction, growth, and metabolism. Two primary hormones of this network, insulin-like growth factor 1 (IGF1) and insulin-like growth factor 2 (IGF2) are important mediators of these processes and, consequently, of life-history strategies. We sprint-trained green anole (Anolis carolinensis) females to test the responsiveness of IGF1 and IGF2 hepatic gene expression to exercise training. We also tested how sprint training would affect glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and eukaryotic elongation factor 2 (EEF2). The former is a crucial enzyme for glycolytic function in a cell, and the latter is necessary for protein synthesis. Resistance exercise forces animals to increase investment of resources towards skeletal muscle growth. Because IGF1 and IGF2 are important hormones for growth, and GAPDH and EEF2 are crucial for proper cellular function, we hypothesized that these four genes would be affected by sprint training. We found that sprint training affects IGF and EEF2 expression, such that larger sprint-trained lizards express hepatic IGF1, IGF2, and EEF2 to a lesser extent than similarly sized untrained lizards. These results demonstrate that the IIS, and pathways connected to it, can react in a size-dependent manner and are implicated in the exercise response in reptiles.

Expression and cellular localization of insulin-like growth factor 3 in gonads of the seasonal breeding teleost silver pomfret (Pampus argenteus)

Insulin-like growth factor 3 plays an important role in gonad development in teleost fish. Previous studies found that igf3 was specifically expressed in gonads of silver pomfret (Pampus argenteus). Unlike in other fish, IGF3 is a membrane protein in silver pomfret, and its specific role in gonads is unclear. Herein, we explored the importance of IGF3 in oogenesis and spermatogenesis in silver pomfret by analyzing gene expression and cellular localization. During follicular development, igf3 was detected in ovaries at both mRNA and protein levels during the critical stages of vitellogenesis (IV-VI). Localization analysis detected igf3 mRNA and protein in somatic cells, including theca and granulosa cells around oocytes. Similar to cathepsin L and cathepsin K, igf3 was consistently expressed in ovaries during vitellogenesis, suggesting that it might play a key role in vitellogenesis of oocytes. During spermatogenesis, igf3 mRNA and protein levels were high in stages II, IV, and V, similar to sycp3 and dmc1, and the highest igf3 mRNA and protein levels were reached in stage VI. Furthermore, igf3 mRNA and protein were detected in spermatogonia, spermatocytes, spermatids, and surrounding Sertoli cells, but not in spermatozoon, indicating that IGF3 might be involved in differentiation and meiosis of spermatogonia.

Pappalysins and Stanniocalcins and Their Relationship With the Peripheral IGF Axis in Newborns and During Development

CONTEXT

Pappalysins (PAPP-A, PAPP-A2) modulate body growth by increasing insulin-like growth factor I (IGF-I) bioavailability through cleavage of insulin-like growth factor binding proteins (IGFBPs) and are inhibited by stanniocalcins (STC1, STC2). Normative data on these novel factors, as well as on free IGF-I and uncleaved fractions of IGFBPs, are not well established.

OBJECTIVE

This work aimed to determine serum concentrations of PAPP-A, PAPP-A2, STC1, and STC2 in relationship with other growth hormone (GH)-IGF axis parameters during development.

METHODS

Full-term newborns (150; gestational age: 39.30 ± 1.10 weeks), 40 preterm newborns (30.87 ± 3.35 weeks), and 1071 healthy individuals (aged 1-30 years) were included in the study and divided according to their Tanner stages (males and females): I:163 males, 154 females; II:100 males, 75 females; III:83 males, 96 females; IV: 77 males, 86 females; and V:109 males,128 females.

RESULTS

Serum concentrations of PAPP-A, PAPP-A2, STC1, STC2, IGFBP-2, total IGFBP-4, and total IGFBP-5 were elevated at birth and declined throughout childhood. In postnatal life, PAPP-A2 concentrations decreased progressively in concomitance with the free/total IGF-I ratio; however, stanniocalcin concentrations remained stable. PAPP-A2 concentrations positively correlated with the free/total IGF-I ratio (r = +0.28; P < .001) and negatively with the intact/total IGFBP-3 ratio (r = -0.23; P < .001). PAPP-A concentrations inversely correlated with intact/total IGFBP-4 ratio (r = -0.21; P < .001), with PAPP-A concentrations being lower in females at all ages. Association studies indicate the importance of stanniocalcins and pappalysins in the control of this axis in an age-specific manner.

CONCLUSION

This study provides reference values of pappalysins and stanniocalcins, which modulate IGF-I activity by changing the concentrations of cleaved and uncleaved IGFBPs.

Comparative transcriptome provides insights into differentially expressed genes between testis and ovary of Onychostoma macrolepis in reproduction period

The Onychostoma macrolepis (O. macrolepis) is a rare and endangered fishery species inhabiting the river of Qinling Mountains and some flowing freshwaters in China. The declining population of O. macrolepis caused by asynchrony of male and female development prompted us to focus on genetic regulation of its reproduction. In this study, high-throughput RNA-sequencing technology was applied to assemble and annotate the transcriptome of O. macrolepis testis and ovary. The results showed that a number of 338089335 (ovary:163216500, testis:174872835) raw sequences were obtained. After non-redundant analysis, a number of 207826065 (ovary:102334008, testis:105492057) high quality reads were obtained and predicted as unigenes, in which 201,038,682 unigenes were annotated with multiple databases. Taking the ovarian transcriptome as a control, comparative transcriptome analysis showed that 9918 differentially expressed genes (DEGs) up-regulated in the testis and 13,095 DEGs down-regulated. Many DEGs were involved with sex-related GO terms and KEGG pathways, such as oocyte maturation, gonadal development, steroid biosynthesis pathways, MAPK signaling pathway and Wnt signaling pathway. Finally, the expression patterns of 19 unigenes were validated by using quantitative real-time polymerase chain reaction (qRT-PCR). This study illustrates a potential molecular mechanism on the unsynchronized male and female development of the O. macrolepis during the reproduction period in June and provides a theoretical basis for future artificial reproduction.

Alterations in insulin-like growth factor system in spinal muscular atrophy

INTRODUCTION/AIMS

Spinal muscular atrophy (SMA) is an inherited neuromuscular disease caused by survival motor neuron (SMN) protein deficiency. Insulin-like growth factor-I (IGF-I) is a myotrophic and neurotrophic factor that has been reported to be dysregulated in in vivo SMA model systems. However, detailed analyses of the IGF-I system in SMA patients are missing. In this study, we analyzed the components of the IGF-I system in serum and archived skeletal muscle biopsies of SMA patients.

METHODS

Serum IGF-I, IGF binding protein (IGFBP)-3, and IGFBP-5 levels were analyzed in 11 SMA patients and 13 healthy children by immunoradiometric and enzyme-linked immunosorbent assays. The expression of IGF-I, IGF-I receptor, and IGFBP-5 proteins was investigated by immunofluorescence analysis in the archived skeletal muscle biopsies of 9 SMA patients, 6 patients with non-SMA-related neuromuscular disease and atrophic fibers in muscle biopsy, and 4 controls.

RESULTS

A significant decrease in IGF-I levels (mean ± SD: -1.39 ± 1.46 vs. 0.017 ± 0.83, p = 0.02) and increase in IGFBP-5 levels (mean ± SD: 2358.5 ± 1617.4 ng/mL vs. 1003.4 ± 274.3 ng/mL, p=0.03) were detected in serum samples of SMA patients compared to healthy controls. Increased expression of IGF-I, IGF-I receptor, and IGFBP-5 was detected in skeletal muscle biopsies of SMA patients and non-SMA neuromuscular diseases, indicating atrophy-specific alterations in the pathway.

DISCUSSION

Our findings suggested that the components of the IGF-I system are altered in SMA patients at both the systemic and tissue-specific levels.

Circulating insulin-like growth factor system adaptations in hibernating brown bears indicate increased tissue IGF availability

Brown bears conserve muscle and bone mass during 6 mo of inactive hibernation. The molecular mechanisms underlying hibernation physiology may have translational relevance for human therapeutics. We hypothesize that protective mechanisms involve increased tissue availability of insulin-like growth factors (IGFs). In subadult Scandinavian brown bears, we observed that mean plasma IGF-1 and IGF-2 levels during hibernation were reduced to 36 ± 10% and 56 ± 15%, respectively, compared with the active state (n = 12). Western ligand blotting identified IGF-binding protein (IGFBP)-3 as the major IGFBP in the active state, whereas IGFBP-2 was codominant during hibernation. Acid labile subunit (ALS) levels in hibernation were reduced to 41±16% compared with the active state (n = 6). Analysis of available grizzly bear RNA sequencing data revealed unaltered liver mRNA IGF-1, IGFBP-2, and IGFBP-3 levels, whereas ALS levels were significantly reduced during hibernation (n = 6). Reduced ALS synthesis and circulating levels during hibernation should prompt a shift from ternary IGF/IGFBP/ALS to smaller binary IGF/IGFBP complexes, thereby increasing IGF tissue availability. Indeed, size-exclusion chromatography of bear plasma demonstrated a shift to lower molecular weight IGF-containing complexes in the hibernating versus the active state. Furthermore, we note that the major IGF-2 mRNA isoform expressed in livers in both Scandinavian brown bears and grizzly bears was an alternative splice variant in which Ser29 is replaced with a tetrapeptide possessing a positively charged Arg residue. Homology modeling of the bear IGF-2/IGFBP-2 complex showed the tetrapeptide in proximity to the heparin-binding domain involved in bone-specific targeting of this complex. In conclusion, this study provides data which suggest that increased IGF tissue availability combined with tissue-specific targeting contribute to tissue preservation in hibernating bears.NEW & NOTEWORTHY Brown bears shift from circulating ternary IGF/IGFBP/ALS complexes in the active state to binary IGF/IGFBP complexes during hibernation, indicating increased tissue IGF-bioactivity. Furthermore, brown bears use a splice variant of IGF-2, suggesting increased bone-specific targeting of IGF anabolic signaling.

The role of exercise-induced myokines in promoting angiogenesis

Ischemic diseases are a major cause of mortality or disability in the clinic. Surgical or medical treatment often has poor effect on patients with tissue and organ ischemia caused by diffuse stenoses. Promoting angiogenesis is undoubtedly an effective method to improve perfusion in ischemic tissues and organs. Although many animal or clinical studies tried to use stem cell transplantation, gene therapy, or cytokines to promote angiogenesis, these methods could not be widely applied in the clinic due to their inconsistent experimental results. However, exercise rehabilitation has been written into many authoritative guidelines in the treatment of ischemic diseases. The function of exercise in promoting angiogenesis relies on the regulation of blood glucose and lipids, as well as cytokines that secreted by skeletal muscle, which are termed as myokines, during exercise. Myokines, such as interleukin-6 (IL-6), chemokine ligand (CXCL) family proteins, irisin, follistatin-like protein 1 (FSTL1), and insulin-like growth factor-1 (IGF-1), have been found to be closely related to the expression and function of angiogenesis-related factors and angiogenesis in both animal and clinical experiments, suggesting that myokines may become a new molecular target to promote angiogenesis and treat ischemic diseases. The aim of this review is to show current research progress regarding the mechanism how exercise and exercise-induced myokines promote angiogenesis. In addition, the limitation and prospect of researches on the roles of exercise-induced myokines in angiogenesis are also discussed. We hope this review could provide theoretical basis for the future mechanism studies and the development of new strategies for treating ischemic diseases.

Species-Specific Expression of Growth-Regulatory Genes in 2 Anoles with Divergent Patterns of Sexual Size Dimorphism

Sexual size dimorphism is widespread in nature and often develops through sexual divergence in growth trajectories. In vertebrates, the growth hormone/insulin-like growth factor (GH/IGF) network is an important regulator of growth, and components of this network are often regulated in sex-specific fashion during the development of sexual size dimorphism. However, expression of the GH/IGF network is not well characterized outside of mammalian model systems, and the extent to which species differences in sexual size dimorphism are related to differences in GH/IGF network expression is unclear. To begin bridging this gap, we compared GH/IGF network expression in liver and muscle from 2 lizard congeners, one with extreme male-biased sexual size dimorphism (brown anole, Anolis sagrei), and one that is sexually monomorphic in size (slender anole, A. apletophallus). Specifically, we tested whether GH/IGF network expression in adult slender anoles resembles the highly sex-biased expression observed in adult brown anoles or the relatively unbiased expression observed in juvenile brown anoles. We found that adults of the 2 species differed significantly in the strength of sex-biased expression for several key upstream genes in the GH/IGF network, including insulin-like growth factors 1 and 2. However, species differences in sex-biased expression were minor when comparing adult slender anoles to juvenile brown anoles. Moreover, the multivariate expression of the entire GH/IGF network (as represented by the first two principal components describing network expression) was sex-biased for the liver and muscle of adult brown anoles, but not for either tissue in juvenile brown anoles or adult slender anoles. Our work suggests that species differences in sex-biased expression of genes in the GH/IGF network (particularly in the liver) may contribute to the evolution of species differences in sexual size dimorphism.

Assessment of Conventional and Low Gossypol Cottonseed Meal as Alternative Protein Sources in Low-Fishmeal Diets of Hybrid Grouper (Epinephelus fuscoguttatus♀× Epinephelus lanceolatus♂): Growth, Feed Utilization, Gut Histology, and Immunity

Simple Summary

The rapid and sustained growth rate of global aquaculture has forced the aquaculture industry to explore alternative and more sustainable feed ingredients. Plant protein ingredients are promising substitutions for fish meal in the aquaculture industry. The current study aimed to investigate the potential influence of replacing poultry by-product meal protein with conventional cottonseed meal protein (CCMP) or low-gossypol cottonseed meal protein (LGCMP) on growth, feed utilization, gut micromorphology, and immunity of hybrid grouper (Epinephelus fuscoguttatus♀× Epinephelus lanceolatus♂) juveniles fed low fish-meal (18.53%, dry matter) diets. Results demonstrated that, without any reduction in fish performance, 80% dietary PBMP could be replaced by CCMP, while this replacement level was 40% for LGCMP. Survival remained unaffected in all dietary treatments, and no fish mortality was observed during the growth trial. These results suggest that cottonseed meal could be a suitable alternative protein source for hybrid grouper farming.

Abstract

A 9-week growth trial was carried out to assess the influence of replacing poultry by-product meal protein with conventional cottonseed meal protein (CCMP) or low gossypol cottonseed meal protein (LGCMP) on growth, feed utilization, gut micromorphology, and immunity of hybrid grouper (Epinephelus fuscoguttatus♀× Epinephelus lanceolatus♂) juveniles fed low-fish meal (18.53%, dry matter) diets. Eleven experimental diets were prepared. The control diet (PBMP) contained 46.15% poultry by-product meal protein. Both conventional cottonseed meal protein (CCMP) and low-gossypol cottonseed meal protein (LGCMP) were used in replacement ratios of 20, 40, 60, 80, and 100% of poultry by-product meal protein (PBMP) from the control diet, forming ten experimental diets (CCMP20, CCMP40, CCMP60, CCMP80, CCMP100, LGCMP20, LGCMP40, LGCMP60, LGCMP80, and LGCMP100). Results demonstrated that weight-gain percentage (WG%) was not different between different sources of cottonseed meal (CCMP and LGCMP). However, values of WG% significantly differed among different replacement levels, with CCMP80 and LGCMP40 having significantly higher values compared to other treatments. Fish fed CCMP80 and LGCMP40 exhibited higher protein efficiency ratios (PERs) than fish fed other experimental diets. The regression analysis from a second-order or third-order polynomial model based on WG% showed that the optimal PBMP replacement levels by CCMP and LGCMP are 74% and 33%, respectively. The whole-body lipid contents remarkably decreased as dietary CCMP or LGCMP inclusion levels increased. The relative mRNA expression of insulin-like growth factor-1(IGF-1) in liver was higher in fish fed CCMP80 and LGCMP40 diets compared to fish fed other diets. Generally, in low-FM diets of hybrid grouper, CCMP and LGCMP could replace 74% and 33% of PBMP, respectively.

Blood Flow Restriction Therapy Preserves Lower Extremity Bone and Muscle Mass After ACL Reconstruction

BACKGROUND

Muscle atrophy is common after an injury to the knee and anterior cruciate ligament reconstruction (ACLR). Blood flow restriction therapy (BFR) combined with low-load resistance exercise may help mitigate muscle loss and improve the overall condition of the lower extremity (LE).

PURPOSE

To determine whether BFR decreases the loss of LE lean mass (LM), bone mass, and bone mineral density (BMD) while improving function compared with standard rehabilitation after ACLR.

STUDY DESIGN

Randomized controlled clinical trial.

METHODS

A total of 32 patients undergoing ACLR with bone-patellar tendon-bone autograft were randomized into 2 groups (CONTROL: N = 15 [male = 7, female = 8; age = 24.1 ± 7.2 years; body mass index [BMI] = 26.9 ± 5.3 kg/m2] and BFR: N = 17 [male = 12, female = 5; age = 28.1 ± 7.4 years; BMI = 25.2 ± 2.8 kg/m2]) and performed 12 weeks of postsurgery rehabilitation with an average follow-up of 2.3 ± 1.0 years. Both groups performed the same rehabilitation protocol. During select exercises, the BFR group exercised under 80% arterial occlusion of the postoperative limb (Delfi tourniquet system). BMD, bone mass, and LM were measured using DEXA (iDXA, GE) at presurgery, week 6, and week 12 of rehabilitation. Functional measures were recorded at week 8 and week 12. Return to sport (RTS) was defined as the timepoint at which ACLR-specific objective functional testing was passed at physical therapy. A group-by-time analysis of covariance followed by a Tukey's post hoc test were used to detect within- and between-group changes. Type I error; α = 0.05.

RESULTS

Compared with presurgery, only the CONTROL group experienced decreases in LE-LM at week 6 (-0.61 ± 0.19 kg, -6.64 ± 1.86%; P < 0.01) and week 12 (-0.39 ± 0.15 kg, -4.67 ± 1.58%; P = 0.01) of rehabilitation. LE bone mass was decreased only in the CONTROL group at week 6 (-12.87 ± 3.02 g, -2.11 ± 0.47%; P < 0.01) and week 12 (-16.95 ± 4.32 g,-2.58 ± 0.64%; P < 0.01). Overall, loss of site-specific BMD was greater in the CONTROL group (P < 0.05). Only the CONTROL group experienced reductions in proximal tibia (-8.00 ± 1.10%; P < 0.01) and proximal fibula (-15.0±2.50%,P < 0.01) at week 12 compared with presurgery measures. There were no complications. Functional measures were similar between groups. RTS time was reduced in the BFR group (6.4 ± 0.3 months) compared with the CONTROL group (8.3 ± 0.5 months; P = 0.01).

CONCLUSION

After ACLR, BFR may decrease muscle and bone loss for up to 12 weeks postoperatively and may improve time to RTS with functional outcomes comparable with those of standard rehabilitation.

Effect of a diet enriched with sodium propionate on growth performance, antioxidant property, innate-adaptive immune response, and growth-related genes expression in critically endangered beluga sturgeon (Huso huso)

Organic acids are active substances required for improving the productivity and wellbeing of aquatic animals. Herein, the study investigated the effects of sodium propionate on growth performance, antioxidative and immune responses, and growth-related genes expression in beluga sturgeon (Huso huso). For eight weeks, fish fed sodium propionate at 0, 1.2, 2.5, and 5 g kg^-1. The final weight, weight gain, and SGR were substantially increased while FCR decreased by dietary sodium propionate at 2.5 and 5 g kg^-1 (P < 0.05). The expression of Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) was markedly upregulated (P < 0.05) by dietary sodium propionate in the gills and livers of beluga. The highest mRNA level of GH and IGF-1 has been observed in fish fed a 2.5 g sodium propionate/kg diet. The red blood cells count, and hemoglobin level were meaningfully increased (P < 0.05) by 2.5 and 5 g sodium propionate/kg diet compared with 0 and 1.2 g kg^-1 levels. Further, the hematocrit level was increased (P < 0.05) by a dietary 5 g sodium propionate/kg diet. The total protein level and lysozyme activity were meaningfully increased (P < 0.05) by 2.5 and 5 g sodium propionate/kg diet compared with 0 and 1.2 g kg^-1 levels. The highest superoxide dismutase was observed in fish fed 2.5 g sodium propionate/kg diet. Catalase activity was significantly higher in fish fed 5 g kg^-1 than 1.2 g kg^-1. The glutathione peroxidase activity was markedly higher in fish fed 2.5, and 5 g kg^-1 than fish fed control diet. The lowest malondialdehyde levels were observed in fish fed 1.2, and 2.5 g sodium propionate/kg diets. Moreover, the highest mucosal total protein, total immunoglobulin and lysozyme were recorded in fish fed 2.5, and 5 g sodium propionate/kg diets. The obtained results indicate that dietary sodium propionate is recommended at 2.5-5 g kg^-1 to improve beluga sturgeon's growth performance, feed utilization, and wellbeing.

Transcriptomes of testis and pituitary from male Nile tilapia (O. niloticus L.) in the context of social status

African cichlids are well established models for studying social hierarchies in teleosts and elucidating the effects social dominance has on gene expression. Ascension in the social hierarchy has been found to increase plasma levels of steroid hormones, follicle stimulating hormone (Fsh) and luteinizing hormone (Lh) as well as gonadosomatic index (GSI). Furthermore, the expression of genes related to gonadotropins and steroidogenesis and signaling along the brain-pituitary-gonad axis (BPG-axis) is affected by changes of an animal’s social status. In this study, we use RNA-sequencing to obtain an in-depth look at the transcriptomes of testes and pituitaries from dominant and subordinate male Nile tilapia living in long-term stable social hierarchies. This allows us to draw conclusions about factors along the brain-pituitary-gonad axis that are involved in maintaining dominance over weeks or even months. We identify a number of genes that are differentially regulated between dominant and subordinate males and show that in high-ranking fish this subset of genes is generally upregulated. Genes differentially expressed between the two social groups comprise growth factors, related binding proteins and receptors, components of Wnt-, Tgfβ- and retinoic acid-signaling pathway, gonadotropin signaling and steroidogenesis pathways. The latter is backed up by elevated levels of 11-ketotestosterone, testosterone and estradiol in dominant males. Luteinizing hormone (Lh) is found in higher concentration in the plasma of long-term dominant males than in subordinate animals. Our results both strengthen the existing models and propose new candidates for functional studies to expand our understanding of social phenomena in teleost fish.

Profiling and Functional Analysis of mRNAs during Skeletal Muscle Differentiation in Goats

Skeletal myogenesis is a complicated biological event that involves a succession of tightly controlled gene expressions. In order to identify novel regulators of this process, we performed mRNA-Seq studies of goat skeletal muscle satellite cells (MuSCs) cultured under proliferation (GM) and differentiation (DM1/DM5) conditions. A total of 19,871 goat genes were expressed during these stages, 198 of which represented novel transcripts. Notably, in pairwise comparisons at the different stages, 2551 differentially expressed genes (DEGs) were identified (p < 0.05), including 1560 in GM vs. DM1, 1597 in GM vs. DM5, and 959 in DM1 vs. DM5 DEGs. The time-series expression profile analysis clustered the DEGs into eight gene groups, three of which had significantly upregulated and downregulated patterns (p < 0.05). Functional enrichment analysis showed that DEGs were enriched for essential biological processes such as muscle structure development, muscle contraction, muscle cell development, striated muscle cell differentiation, and myofibril assembly, and were involved in pathways such as the MAPK, Wnt and PPAR signaling pathways. Moreover, the expression of eight DEGs (MYL2, DES, MYOG, FAP, PLK2, ADAM, WWC1, and PRDX1) was validated. These findings offer novel insights into the transcriptional regulation of skeletal myogenesis in goats.

Functional Differentiation of BMP7 Genes in Zebrafish: bmp7a for Dorsal-Ventral Pattern and bmp7b for Melanin Synthesis and Eye Development

Bone morphogenetic protein 7 (BMP7) belongs to the transforming growth factor β (TGF-β) family, which not only induces cartilage and bone formation, but also regulates eye development and melanoma tumorigenesis in mammals. In teleosts, BMP7 differentiates into two subtypes, bmp7a and bmp7b, which have clearly differentiated structures. To fully understand the functional differentiation of bmp7a and bmp7b in fish species, we successfully constructed bmp7a and bmp7b gene deletion mutants in zebrafish using CRISPR/Cas9-mediated gene editing technology. Our results showed that bmp7a mutation caused abnormal development of the embryo’s dorsal-ventral pattern that led to death; bmp7b mutation induced growth inhibition and increased melanin production in the skin and eye of mutants. Histological analysis revealed that melanin in the retina of the eyes in bmp7b mutants increased, and behavioral observation showed that the vision and sensitivity to food of the mutants were reduced. Transcriptome analysis of the skin and eye tissues showed that the expression changes of wnt7ba and gna14 in bmp7b mutants might promote the increase of melanin. Additionally, the eye transcriptome analysis indicated that changes in the structure of the eyes in bmp7b mutants led to defects in phototransduction, and seven DEGs (rgs9a, rgs9b, rcvrn2, guca1d, grk1b, opn1mw4, and gc2) were identified as key candidate genes that affected the photonic response of the eyes. The study revealed the functional differentiation of bmp7a and bmp7b in teleosts and the first report about the inhibitory effect of bmp7b on melanogenesis may provide useful information for the future research on human melanoma-related diseases.

Myostatin/Activin Receptor Ligands in Muscle and the Development Status of Attenuating Drugs

Muscle wasting disease indications are among the most debilitating and often deadly noncommunicable disease states. As a comorbidity, muscle wasting is associated with different neuromuscular diseases and myopathies, cancer, heart failure, chronic pulmonary and renal diseases, peripheral neuropathies, inflammatory disorders, and, of course, musculoskeletal injuries. Current treatment strategies are relatively ineffective and can at best only limit the rate of muscle degeneration. This includes nutritional supplementation and appetite stimulants as well as immunosuppressants capable of exacerbating muscle loss. Arguably, the most promising treatments in development attempt to disrupt myostatin and activin receptor signaling because these circulating factors are potent inhibitors of muscle growth and regulators of muscle progenitor cell differentiation. Indeed, several studies demonstrated the clinical potential of "inhibiting the inhibitors," increasing muscle cell protein synthesis, decreasing degradation, enhancing mitochondrial biogenesis, and preserving muscle function. Such changes can prevent muscle wasting in various disease animal models yet many drugs targeting this pathway failed during clinical trials, some from serious treatment-related adverse events and off-target interactions. More often, however, failures resulted from the inability to improve muscle function despite preserving muscle mass. Drugs still in development include antibodies and gene therapeutics, all with different targets and thus, safety, efficacy, and proposed use profiles. Each is unique in design and, if successful, could revolutionize the treatment of both acute and chronic muscle wasting. They could also be used in combination with other developing therapeutics for related muscle pathologies or even metabolic diseases.

Blood Flow Restriction Enhances Rehabilitation and Return to Sport: The Paradox of Proximal Performance

The use of blood flow restriction (BFR) within rehabilitation is rapidly increasing as further research is performed elucidating purported benefits such as improved muscular strength and size, neuromuscular control, decreased pain, and increased bone mineral density. Interestingly, these benefits are not isolated to structures distal to the occlusive stimulus. Proximal gains are of high interest to rehabilitation professionals, especially those working with patients who are limited due to pain or postsurgical precautions. The review to follow will focus on current evidence and ongoing hypotheses regarding physiologic responses to BFR, current clinical applications, proximal responses to BFR training, potential practical applications for rehabilitation and injury prevention, and directions for future research. Interestingly, benefits have been found in musculature proximal to the occlusive stimulus, which may lend promise to a greater variety of patient populations and conditions. Furthermore, an increasing demand for BFR use in the sports world warrants further research for performance research and recovery.

LEVEL OF EVIDENCE

Level V, expert opinion.

Differential expression analyses reveal extensive transcriptional plasticity induced by temperature in New Zealand silver trevally (Pseudocaranx georgianus)

Ectotherm species, such as marine fishes, depend on environmental temperature to regulate their vital functions. In finfish aquaculture production, being able to predict physiological responses in growth and other economic traits to temperature is crucial to address challenges inherent in the selection of grow-out locations. This will become an even more significant issue under the various predicted future climate change scenarios. In this study, we used the marine teleost silver trevally (Pseudocaranx georgianus), a species currently being explored as a candidate for aquaculture in New Zealand, as a model to study plasticity in gene expression patterns and growth in response to different temperatures. Using a captive study population, temperature conditions were experimentally manipulated for 1 month to mimic seasonal extremes. Phenotypic differences in growth were measured in 400 individuals, and gene expression patterns of pituitary gland and liver were determined in a subset of 100 individuals. Results showed that growth increased 50% in the warmer compared with the colder condition, suggesting that temperature has a large impact on metabolic activities associated with growth. A total of 265,116,678 single-end RNA sequence reads were aligned to the trevally genome, and 28,416 transcript models were developed (27,887 of these had GenBank accessions, and 17,980 unique gene symbols). Further filtering reduced this set to 8597 gene models. 39 and 238 differentially expressed genes (DEGs) were found in the pituitary gland and the liver, respectively (|log2FC| > 0.26, p-value < 0.05). Of these, 6 DEGs showed a common expression pattern between both tissues, all involved in housekeeping functions. Temperature-modulated growth responses were linked to major pathways affecting metabolism, cell regulation and signalling, previously shown to be important for temperature tolerance in other fish species. An interesting finding of this study was that genes linked to the reproductive system were up-regulated in both tissues in the high treatment, indicating the onset of sexual maturation. Few studies have investigated the thermal plasticity of the gene expression in the main organs of the somatotropic axis simultaneously. Our findings indicate that trevally exhibit substantial growth differences and predictable plastic regulatory responses to different temperature conditions. We identified a set of genes that provide a list of candidates for further investigations for selective breeding objectives and how populations may adapt to increasing temperatures.

Consumption of Dairy Products and the Risk of Developing Breast Cancer in Polish Women

Lack of consistency in the relationship between dairy products consumption and breast cancer (BC) risk motivated us to evaluate this association in a case-control study of BC among Polish women. The study includes 1699 women 26–79 years of age, 823 BC cases identified in Cancer Registries and 876 randomly selected controls from the national population registry. Using a validated, semiquantitative food frequency questionnaire (FFQ), the consumption of dairy products was collected for a time period of 10–15 years prior to BC diagnosis. We used logistic regression, adjusting for potential confounders, to assess the relationship between total dairy consumption as well as individual dairy groups of milk, cottage cheese and hard cheese and BC risk for premenopausal and postmenopausal women. For total consumption, a significant decrease in BC risk was observed with increased consumption of one serving/week, OR _trend = 0.98, 2% decrease in risk, for premenopausal women only. For milk, a significant decrease in BC risk was observed for an increase in consumption of one glass/week, OR _trend = 0.95, 5% decrease, in both strata of menopause. In contrast, for hard cheese, a significant increase in the risk of 10% was observed only in premenopausal women, OR _trend = 1.10. Cottage cheese consumption significantly reduced BC risk by 20%, OR _trend = 0.80, for an increase in one serving/week for postmenopausal women only. Our results show that individual dairy products have a statistically significant but bi-directional relationship with BC risk, which differs for premenopausal and postmenopausal women.

Alteration of organ size and allometric scaling by organ-specific targeting of IGF signaling

The size of an organ is proportional to the other body parts or the whole body. This relationship is known as allometry. Understanding how allometry is determined is a fundamental question in biology. Here we tested the hypothesis that local insulin-like growth factor (Igf) signaling is critical in regulating organ size and its allometric scaling by organ-specific expression of Igf binding protein (Igfbp). Overexpression of Igfbp2a or 5b in the developing zebrafish eye, heart, and inner ear resulted in a disproportional reduction in their growth relative to the body. Stable transgenic zebrafish with lens-specific Igfbp5b expression selectively reduced adult eye size. The action is Igf-dependent because an Igf-binding deficient Igfbp5b mutant had no effect. Targeted expression of a dominant-negative Igf1 receptor (dnIgf1r) in the lens caused a similar reduction in relative eye growth. Furthermore, co-expression of IGF-1 with an Igfbp restored the eye size. Finally, co-expression of a constitutively active form of Akt with Igfbp or dnIgf1r restored the relative eye growth. These data suggest that local Igf availability and Igf signaling activity are critical determinants of organ size and allometric scaling in zebrafish.

Venlafaxine deposition in the zygote disrupts the endocrine control of growth in juvenile zebrafish

The antidepressant venlafaxine can be found at levels nearing μg/L in waterways receiving municipal wastewater effluent, exposing non-target organisms, such as fish, to this chemical. We showed previously that zygotic exposure to venlafaxine alters neurodevelopment and behaviour in zebrafish (Danio rerio) larvae. Here, we tested the hypothesis that the zygotic deposition of venlafaxine disrupts endocrine pathways related to growth in zebrafish. This was carried out by microinjecting embryos (1-4 cell stage) with either 0, 1, or 10 ng venlafaxine. Zygotic venlafaxine deposition reduced the growth of fish after 30 days post-fertilization. Specific growth rate was particularly impacted by 1 ng venlafaxine. This growth retardation corresponded with the disruption of endocrine pathways involved in growth and metabolism. Venlafaxine exposed embryos displayed reduced transcript abundance of key genes involved in anabolic hormone action. Early-life venlafaxine exposure also reduced whole-body insulin and glucose content in juveniles. Target-tissue glucose uptake measurements indicated that high venlafaxine deposition preferentially increased glucose uptake to the brain. Zygotic venlafaxine did not affect feed intake nor altered the transcript abundance of key feeding-related peptides. Taken together, zygotic venlafaxine deposition compromises zebrafish growth by disrupting multiple endocrine pathways, and this study has identified key markers for potential use in risk assessment.

Analysis of potential regulatory LncRNAs and CircRNAs in the oxidative myofiber and glycolytic myofiber of chickens

SART and PMM are mainly composed of oxidative myofibers and glycolytic myofibers, respectively, and myofiber types profoundly influence postnatal muscle growth and meat quality. SART and PMM are composed of lncRNAs and circRNAs that participate in myofiber type regulation. To elucidate the regulatory mechanism of myofiber type, lncRNA and circRNA sequencing was used to systematically compare the transcriptomes of the SART and PMM of Chinese female Qingyuan partridge chickens at their marketing age. The luminance value (L*), redness value (a*), average diameter, cross-sectional area, and density difference between the PMM and SART were significant (p < 0.05). ATPase staining results showed that PMMs were all darkly stained and belonged to the glycolytic type, and the proportion of oxidative myofibers in SART was 81.7%. A total of 5 420 lncRNAs were identified, of which 365 were differentially expressed in the SART compared with the PMM (p < 0.05). The cis-regulatory analysis identified target genes that were enriched for specific GO terms and KEGG pathways (p < 0.05), including striated muscle cell differentiation, regulation of cell proliferation, regulation of muscle cell differentiation, myoblast differentiation, regulation of myoblast differentiation, and MAPK signaling pathway. Pathways and coexpression network analyses suggested that XR_003077811.1, XR_003072304.1, XR_001465942.2, XR_001465741.2, XR_001470487.1, XR_003077673.1 and XR_003074785.1 played important roles in regulating oxidative myofibers by TBX3, QKI, MYBPC1, CALM2, and PPARGC1A expression. A total of 10 487 circRNAs were identified, of which 305 circRNAs were differentially expressed in the SART compared with the PMM (p < 0.05). Functional enrichment analysis showed that differentially expressed circRNAs were involved in host gene expression and were enriched in the AMPK, calcium signaling pathway, FoxO signaling pathway, p53 signaling pathway, and cellular senescence. Novel_circ_004282 and novel_circ_002121 played important roles in regulating oxidative myofibers by PPP3CA and NFATC1 expression. Using lncRNA-miRNA/circRNA-miRNA integrated analysis, we identified many candidate interaction networks that might affect muscle fiber performance. Important lncRNA-miRNA-mRNA networks, such as lncRNA-XR_003074785.1/miR-193-3p/PPARGC1A, regulate oxidative myofibers. This study reveals that lncXR_003077811.1, lncXR_003072304.1, lncXR_001465942.2, lncXR_001465741.2, lncXR_001470487.1, lncXR_003077673.1, XR_003074785.1, novel_circ_004282 and novel_circ_002121 might regulate oxidative myofibers. The lncRNA-XR_003074785.1/miR-193-3p/PPARGC1A pathway might regulate oxidative myofibers. All these findings provide rich resources for further in-depth research on the regulatory mechanism of lncRNAs and circRNAs in myofibers.

Effects of Administering Exogenous Bovine Somatotropin During the First Trimester of Pregnancy Altered Uterine Hemodynamics in Suckled Beef Cows

The objective of this study was to examine the effects of recombinant bovine somatotropin (bST) administration on uterine hemodynamics and subsequent fetal programming in suckled cows during the first trimester of gestation. Crossbred beef cows (n = 152) were stratified by breed, days postpartum, parity, cyclicity status, and body condition score (BCS) before being assigned to either receive injections of bST every other week (BST; 500-mg/14 d) starting at fixed-time artificial insemination (TAI; d 0) until d 97 or to receive no bST (CTL). Blood samples were collected until d 97 for analysis of plasma concentrations of insulin-like growth factor 1 (IGF-1). Pregnancy was assessed via transrectal ultrasonography on d 41 and 173. A subset of pregnant cows (BST, n = 24; CTL, n = 28) were selected for assessment of uterine arterial blood flow (BF), pulsatility index, and resistance index (RI) of the uterine arteries ipsilateral and contralateral to the conceptus via color Doppler ultrasonography on d 97 and 233 of gestation. No differences (P = 0.99) were detected in body weight (BW) or BCS of dams; however, plasma concentrations of IGF-1 were greater (P &lt; 0.001) in BST-treated cows. Color Doppler ultrasonography parameters differed whereby a treatment × day interaction (P = 0.007) was detected for RI on d 97 (P = 0.048); however, on d 233, RI did not differ (P &gt; 0.10) but ipsilateral BF for BST-treated cows was greater (P = 0.0319) than controls. Mean heart girth diameter, crown-to-rump length, and neonate BW at 7 ± 5 d of calf age did not differ (P &gt; 0.10). Liver tissue samples from each calf were collected for analysis of mRNA expression of target insulin-like growth factor system ligands. There was no difference in gene expression of hepatic IGF-1 between treatments (P = 0.99). A treatment × sex interaction was determined, where BST heifers had increased mRNA expression of IGFR1 compared to BST bulls (P = 0.03). Bi-weekly administration of bST until d 97 of pregnancy increased plasma concentrations of IGF-1, altered uterine hemodynamics in dams, induced sex-specific changes in liver gene expression of the offspring but failed to alter calf morphometries or calf performance until weaning.