Insulin-like growth factor II (IGF-II)

IGF signaling pathway in bone and cartilage development, homeostasis, and disease

The skeleton plays a fundamental role in the maintenance of organ function and daily activities. The insulin-like growth factor (IGF) family is a group of polypeptide substances with a pronounced role in osteoblast differentiation, bone development, and metabolism. Disturbance of the IGFs and the IGF signaling pathway is inextricably linked with assorted developmental defects, growth irregularities, and jeopardized skeletal structure. Recent findings have illustrated the significance of the action of the IGF signaling pathway via growth factors and receptors and its interactions with dissimilar signaling pathways (Wnt/β-catenin, BMP, TGF-β, and Hh/PTH signaling pathways) in promoting the growth, survival, and differentiation of osteoblasts. IGF signaling also exhibits profound influences on cartilage and bone development and skeletal homeostasis via versatile cell-cell interactions in an autocrine, paracrine, and endocrine manner systemically and locally. Our review summarizes the role and regulatory function as well as a potentially integrated gene network of the IGF signaling pathway with other signaling pathways in bone and cartilage development and skeletal homeostasis, which in turn provides an enlightening insight into visualizing bright molecular targets to be eligible for designing effective drugs to handle bone diseases and maladies, such as osteoporosis, osteoarthritis, and dwarfism.

Recurrent Non-islet Cell Tumor Hypoglycemia Secondary to Hepatocellular Carcinoma: Case Report and Literature Review

RATIONALE

Non-islet cell tumor hypoglycemia (NICTH) is a paraneoplastic syndrome caused by tumors other than insulinoma that is primarily due to excessive production of insulin-like growth factor-II (IGF-II). The prevalence of NICTH is likely underestimated because of a lack of clinical recognition.

PATIENT CONCERNS

A 41-year-old male with massive malignant liver tumors presented with recurrent severe hypoglycemia, weight loss, and liver cirrhosis.

DIAGNOSIS

NICTH related to IGF-II produced by hepatocellular carcinoma was diagnosed based on clinical symptoms, biochemical tests, and elevated IGF-II/IGF-I ratio.

INTERVENTION

Initial treatment with intravenous glucose and parenteral nutrition showed limited efficacy. Glucocorticoids and recombinant human growth hormone led to progressive improvement in blood glucose levels.

OUTCOME

Due to extensive tumor burden and liver failure, surgical resection was not feasible, and the patient ultimately succumbed to refractory hypoglycemia and passed away in two weeks.

LESSONS

Early recognition and diagnosis of NICTH are crucial in patients with recurrent hypoglycemia and large tumors. Surgical resection is the preferred treatment option, but supportive care and pharmacological interventions, such as glucocorticoids and growth hormone, can help manage refractory hypoglycemia. Further research is needed to explore novel treatment options, including anti-IGF-I and -IGF-II neutralizing antibodies.

C. elegans insulin-like peptides

Insulin-like peptides are a group of hormones crucial for regulating metabolism, growth, and development in animals. Invertebrates, such as C. elegans, have been instrumental in understanding the molecular mechanisms of insulin-like peptides. Here, we review the 40 insulin-like peptide genes encoded in the C. elegans genome. Despite the large number, there is only one C. elegans insulin-like peptide receptor, called DAF-2. The insulin and insulin-like growth factor signaling (IIS) pathway is evolutionarily conserved from worms to humans. Thus C. elegans provides an excellent model to understand how these insulin-like peptides function. C. elegans is unique in that it possesses insulin-like peptides that have antagonistic properties, unlike all human insulin-like peptides, which are agonists. This review provides an overview of the current literature on C. elegans insulin-like peptide structures, processing, tissue localization, and regulation. We will also provide examples of insulin-like peptide signaling in C. elegans during growth, development, germline development, learning/memory, and longevity.

Pleomorphic adenoma gene1 in reproduction and implication for embryonic survival in cattle: a review

The pleomorphic adenoma gene1 (PLAG1) encodes a DNA-binding, C2H2 zinc-finger protein which acts as a transcription factor that regulates the expression of diverse genes across different organs and tissues; hence, the name pleomorphic. Rearrangements of the PLAG1 gene, and/or overexpression, are associated with benign tumors and cancers in a variety of tissues. This is best described for pleomorphic adenoma of the salivary glands in humans. The most notable expression of PLAG1 occurs during embryonic and fetal development, with lesser expression after birth. Evidence has accumulated of a role for PLAG1 protein in normal early embryonic development and placentation in mammals. PLAG1 protein influences the expression of the ike growth factor 2 (IGF2) gene and production of IGF2 protein. IGF2 is an important mitogen in ovarian follicles/oocytes, embryos, and fetuses. The PLAG1-IGF2 axis, therefore, provides one pathway whereby PLAG1 protein can influence embryonic survival and pregnancy. PLAG1 also influences over 1,000 other genes in embryos including those associated with ribosomal assembly and proteins. Brahman (Bos indicus) heifers homozygous for the PLAG1 variant, rs109815800 (G > T), show greater fertility than contemporary heifers with either one, or no copy, of the variant. Greater fertility in heifers homozygous for rs109815800 could be the result of early puberty and/or greater embryonic survival. The present review first looks at the broader roles of the PLAG1 gene and PLAG1 protein and then focuses on the emerging role of PLAG1/PLAG1 in embryonic development and pregnancy. A deeper understanding of factors which influence embryonic development is required for the next transformational increase in embryonic survival and successful pregnancy for both in vivo and in vitro derived embryos in cattle.

IGF2/IGF2R/Sting signaling as a therapeutic target in DSS-induced ulcerative colitis

Ulcerative colitis is an inflammatory bowel disease with increasing prevalence and incidence. Current treatments for ulcerative colitis are not generally applicative and are often accompanied by side effects. IGF2 is an endogenous protein that plays roles in anti-inflammation and stemness maintenance, but little is known about its mechanism and function in the progression of ulcerative colitis. In this study, mouse recombinant IGF2 was used in a mouse model of ulcerative colitis established by DSS. IGF2 expression was reduced in colon tissues but not plasma of DSS-induced colitis mice. IGF2R expression was also decreased in colitis colons, which was then elevated by recombinant IGF2. Recombinant IGF2 alleviated colon injury in colitis, which was evaluated by colon shortening, body weight loss and DAI score. IGF2 treatment also relieved the inflammatory response in colitis, which was assessed by the spleen weight index, MPO activity and proinflammatory cytokine expression and was also detected in LPS-stimulated RAW264.7 cells in vitro. Moreover, IGF2R was predicted and further verified to interact with the Sting protein, and the cGAS-Sting pathway as a key pathway for stemness regulation, was upregulated in colonic colons, which was blocked by IGF2 treatment. Additionally, IGF2 treatment can maintain colonic stemness and further repair colonic tight junction function in DSS-induced colitis. In conclusion, IGF2/IGF2R downregulated the cGAS-Sting pathway to sustain colonic stemness and barrier integrity to protect against ulcerative colitis induced by DSS.

Molecular cloning and expression profiling of insulin-like growth factor 2 and IGF-binding protein 6 in Clarias magur (Hamilton 1822)

Growth is an important trait in aquaculture and the major genes that regulate it are Insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs). In this study, the full-length coding sequences of IGF2 and IGFBP6 genes in the Indian catfish Clarias magur were cloned and characterized. The full-length cDNA sequences of IGF2 and IGFBP6 were 885 bp (ORF 642 bp) and 928 bp (ORF 600 bp), encoding 213 and 199 amino acids, respectively. Bioinformatics analyses revealed that the magur IGF2 and IGFBP6 proteins are hydrophilic and secretory in nature. Sequence alignment with other teleosts and mammalian orthologues shows conservation of the functional domains. Gene expression analysis in 6 individuals each of high (298 ± 5.0 g) and low (210 ± 6.0 g) growth performing families showed significantly (p < 0.05) higher expression (2.5-3 fold) of IGF2, and lower expression (∼2.5 fold) of IGFBP6 in liver and muscle of fast-growing fish. This study suggests that IGF2 could be playing a major role in the growth regulation of magur. These genes and their expression patterns could be developed into growth-associated markers for magur and other catfishes.

Effects and potential mechanisms of IGF1/IGF1R in the liver fibrosis: A review

Liver fibrosis is a wound-healing response due to persistent liver damage and it may progress to cirrhosis and even liver cancer if no intervention is given. In the current cognition, liver fibrosis is reversible. So, it is of great significance to explore the related gene targets or biomarker for anti-fibrosis of liver. Insulin like growth factor 1 (IGF1) and IGF1 receptor (IGF1R) are mainly expressed in the liver tissues and play critical roles in the liver function. The present review summarized the role of IGF1/IGF1R and its signaling system in liver fibrosis and illustrated the potential mechanisms including DNA damage repair, cell senescence, lipid metabolism and oxidative stress that may be involved in this process according to the studies on the fibrosis of liver or other organs. In particular, the roles of IGF1 and IGF1R in DNA damage repair were elaborated, including membrane-localized and nucleus-localized IGF1R. In addition, for each of the potential mechanism in anti-fibrosis of liver, the signaling pathways of the IGF1/IGF1R mediated and the cell species in liver acted by IGF1 and IGF1R under different conditions were included. The data in this review will support for the study about the effect of IGF1/IGF1R on liver fibrosis induced by various factors, meanwhile, provide a basis for the study of liver fibrosis to focus on the communications between the different kinds of liver cells.

Recurrence of solitary fibrous tumor of the pleura with hypoglycemia (Doege-Potter Syndrome): a case report description

Hypoglycemia has multiple causes, but the most common is a complication of insulin treatment. In addition to insulin therapy, tumors such as insulinomas of pancreatic origin and extrapancreatic tumors causing paraneoplastic syndromes should also be considered. Solitary fibrous tumors of the pleura (SFTP) is rare tumor, which when associated with hypoglycemia causes Doege-Potter syndrome. This article reports a case of a 69-year-old man with Doege-Potter syndrome and underwent the first surgical resection for SFTP. However, the tumor recurred 9 years later with hypoglycemic symptoms and implant metastasis. This recurrent tumor originated from the visceral pleura, was more aggressive and invaded the diaphragm and parietal pleura. After the second surgical removal of the tumor, the hypoglycemic symptoms disappeared.

The Glycosaminoglycan Side Chains and Modular Core Proteins of Heparan Sulphate Proteoglycans and the Varied Ways They Provide Tissue Protection by Regulating Physiological Processes and Cellular Behaviour

This review examines the roles of HS-proteoglycans (HS-PGs) in general, and, in particular, perlecan and syndecan as representative examples and their interactive ligands, which regulate physiological processes and cellular behavior in health and disease. HS-PGs are essential for the functional properties of tissues both in development and in the extracellular matrix (ECM) remodeling that occurs in response to trauma or disease. HS-PGs interact with a biodiverse range of chemokines, chemokine receptors, protease inhibitors, and growth factors in immune regulation, inflammation, ECM stabilization, and tissue protection. Some cell regulatory proteoglycan receptors are dually modified hybrid HS/CS proteoglycans (betaglycan, CD47). Neurexins provide synaptic stabilization, plasticity, and specificity of interaction, promoting neurotransduction, neurogenesis, and differentiation. Ternary complexes of glypican-1 and Robbo-Slit neuroregulatory proteins direct axonogenesis and neural network formation. Specific neurexin-neuroligin complexes stabilize synaptic interactions and neural activity. Disruption in these interactions leads to neurological deficits in disorders of functional cognitive decline. Interactions with HS-PGs also promote or inhibit tumor development. Thus, HS-PGs have complex and diverse regulatory roles in the physiological processes that regulate cellular behavior and the functional properties of normal and pathological tissues. Specialized HS-PGs, such as the neurexins, pikachurin, and Eyes-shut, provide synaptic stabilization and specificity of neural transduction and also stabilize the axenome primary cilium of phototoreceptors and ribbon synapse interactions with bipolar neurons of retinal neural networks, which are essential in ocular vision. Pikachurin and Eyes-Shut interactions with an α-dystroglycan stabilize the photoreceptor synapse. Novel regulatory roles for HS-PGs controlling cell behavior and tissue function are expected to continue to be uncovered in this fascinating class of proteoglycan.

The variation of insulin like growth factor 2 maker is associated with growth traits in Thai native (Kradon) pigs

OBJECTIVE

This study was conducted to investigate polymorphisms of the melanocortin-4 receptor (MC4R) and insulin like growth factor 2 (IGF2) genes and to evaluate the growth traits affected by such polymorphisms in Thai native (Kradon) pigs.

METHODS

Blood samples and productive data from 91 Kradon pigs were collected. DNA was extracted and quantified, the IGF2 and MC4R genes were amplified, and the polymerase chain reaction (PCR) produces were digested using the PCR-restriction fragment length polymorphism (PCR-RFLP) technique. Genotyping was performed, and the association between genotypes and growth traits on the birth and weaning weights were evaluated.

RESULTS

The IGF2 intron7 g.162G>C variations in Kradon pigs were found in three genotypes: i) GG, ii) GC, and iii) CC. The GG genotype frequency was the highest followed by the GC and CC genotypes. The frequencies of the G and C alleles were 0.703 and 0.297, respectively. The MC4R genotype was found in only one genotype (GG). The IGF2 gene pattern was not associated with birth weight traits, whereas the IGF2 gene pattern was related to the weaning weight trait in Kradon pigs. Pigs with the CC and GC genotypes had higher weaning weights than ones with the GG genotype (p<0.001).

CONCLUSION

Thai native Kradon pigs with the CC and GC genotypes of the IGF2 gene have higher weaning weights than pigs with the GG genotype.

Hypoglycemia in Children: Major Endocrine-Metabolic Causes and Novel Therapeutic Perspectives

Hypoglycemia is due to defects in the metabolic systems involved in the transition from the fed to the fasting state or in the hormone control of these systems. In children, hypoglycemia is considered a metabolic-endocrine emergency, because it may lead to brain injury, permanent neurological sequelae and, in rare cases, death. Symptoms are nonspecific, particularly in infants and young children. Diagnosis is based on laboratory investigations during a hypoglycemic event, but it may also require biochemical tests between episodes, dynamic endocrine tests and molecular genetics. This narrative review presents the age-related definitions of hypoglycemia, its pathophysiology and main causes, and discusses the current diagnostic and modern therapeutic approaches.

Potential Effects of High Temperature and Heat Wave on Nanorana pleskei Based on Transcriptomic Analysis

In the context of climate change, understanding how indigenous amphibians of the Qinghai-Tibet plateau react to stresses and their coping mechanisms could be crucial for predicting their fate and successful conservation. A liver transcriptome for Nanorana pleskei was constructed using high-throughput RNA sequencing, and its gene expression was compared with frogs acclimated under either room temperature or high temperature and also heat wave exposed ones. A total of 126,465 unigenes were produced, with 66,924 (52.92%) of them being annotated. Up to 694 genes were found to be differently regulated as a result of abnormal temperature acclimatization. Notably, genes belonging to the heat shock protein (HSP) family were down-regulated in both treated groups. Long-term exposure to high-temperature stress may impair the metabolic rate of the frog and trigger the body to maintain a hypometabolic state in an effort to survive challenging times. During heat waves, unlike the high-temperature group, mitochondrial function was not impaired, and the energy supply was largely normal to support the highly energy-consuming metabolic processes. Genes were more transcriptionally suppressed when treated with high temperatures than heat waves, and the body stayed in low-energy states for combating these long-term adverse environments to survive. It might be strategic to preserve initiation to executive protein activity under heat wave stress. Under both stress conditions, compromising the protection of HSP and sluggish steroid activity occurred in frogs. Frogs were more affected by high temperatures than by heat waves.

Role of neurotrophic and growth factors in the rapid and sustained antidepressant actions of ketamine

The neurotrophic hypothesis of depression proposes that reduced levels of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) contribute to neuronal atrophy or loss in the prefrontal cortex (PFC) and hippocampus and impaired hippocampal adult neurogenesis, which are associated with depressive symptoms. Chronic, but acute, treatment with typical monoaminergic antidepressants can at least partially reverse these deficits, in part via induction of BDNF and/or VEGF expression, consistent with their delayed onset of action. Ketamine, an N-methyl-d-aspartate receptor antagonist, exerts rapid and sustained antidepressant effects. Rodent studies have revealed that ketamine rapidly increases BDNF and VEGF release and/or expression in the PFC and hippocampus, which in turn increases the number and function of spine synapses in the PFC and hippocampal neurogenesis. Ketamine also induces the persistent release of insulin-like growth factor 1 (IGF-1) in the PFC of male mice. These neurotrophic effects of ketamine are associated with its rapid and sustained antidepressant effects. In this review, we first provide an overview of the neurotrophic hypothesis of depression and then discuss the role of BDNF, VEGF, IGF-1, and other growth factors (IGF-2 and transforming growth factor-β1) in the antidepressant effects of ketamine and its enantiomers. This article is part of the Special Issue on 'Ketamine and its Metabolites'.

Paraneoplastic Hypoglycemia Leading to Insulin Independence in a Patient With Type 1 Diabetes

Objective

Non–islet cell tumor hypoglycemia (NICTH) is an uncommon paraneoplastic syndrome associated with mesenchymal neoplasms such as gastrointestinal stromal tumors (GISTs). We report the case of a patient with type 1 diabetes (T1D) and recurrent GIST who not only required discontinuation of insulin therapy but also required continuous parenteral glucose infusions to prevent hypoglycemia.

Methods

A 59-year-old woman with a 24-year history of T1D and recurrent GIST presented with frequent episodes of symptomatic hypoglycemia despite continuous reductions in her insulin therapy. Laboratory workup revealed undetectable insulin and C-peptide, low insulin-like growth factor (IGF) 1, normal IGF-2, and an elevated IGF-2:IGF-1 ratio. Medical management with prednisone alone and, later, in combination with octreotide did not reduce hypoglycemic episodes. Eventually, during hospitalization for severe hypoglycemia, she was treated and discharged with continuous intravenous dextrose infusion. She ultimately required around-the-clock glucose infusions, which helped her maintain what she believed was an acceptable quality of life during her remaining weeks.

Discussion

NICTH is characterized by excessive tumor production of IGF-2 or pro-IGF-2, leading to unrestricted glucose uptake in peripheral tissues and hypoglycemia. A diagnosis of NICTH can be made on the basis of low IGF-1 levels in the plasma with normal or elevated IGF-2. Tumor resection is the most definitive treatment for NICTH.

Conclusion

This patient with T1D presented with resistant hypoglycemia due to recurrence of an enlarging GIST. She required discontinuation of all insulin therapy and continuous dextrose infusions to maintain euglycemia.

The Emerging Role of the Fetal Insulin Receptor in Hormone-refractory Breast Cancer

Type 1 insulin-like growth factor receptor (IGF-1R) is a transmembrane tyrosine kinase receptor and a mediator of the biologic effects of insulin-like growth factor (IGF)-I and -II. Inhibitors of IGF-1R signaling were tested in clinical cancer trials aiming to assess the utility of this receptor as a therapeutic target; essentially all IGF-1R inhibitors failed to provide an additional benefit compared with standard-of-care therapy. In this review, we will evaluate the role the insulin receptor (IR) plays in mediating IGF signaling and subsequent metabolic and mitogenic effects as 1 possible reason for these failures. IR is expressed as 2 isoforms, with the fetal isoform IR-A derived from alternative splicing and loss of exon 11, the adult isoform (IR-B) includes this exon. Cancer frequently re-expresses fetal proteins and this appears to be the case in cancer with a re-expression of the fetal isoform and an increased IR-A:IR-B ratio. The biological effects of IR isoform signaling are complex and not completely understood although it has been suggested that IR-A could stimulate mitogenic signaling pathways, play a role in cancer cell stemness, and mediate tolerance to cancer therapies. From a clinical perspective, the IR-A overexpression in cancer may explain why targeting IGF-1R alone was not successful. However, given the predominance of IR-A expression in cancer, it may also be possible to develop isoform specific inhibitors and avoid the metabolic consequences of inhibiting IR-B. If such inhibitors could be developed, then IR-A expression could serve as a predictive biomarker, and cotargeting IR-A and IGF-1R could provide a novel, more effective therapy method.

Targeting obesity-related dysfunction in hormonally driven cancers

Obesity is a risk factor for at least 13 different types of cancer, many of which are hormonally driven, and is associated with increased cancer incidence and morbidity. Adult obesity rates are steadily increasing and a subsequent increase in cancer burden is anticipated. Obesity-related dysfunction can contribute to cancer pathogenesis and treatment resistance through various mechanisms, including those mediated by insulin, leptin, adipokine, and aromatase signalling pathways, particularly in women. Furthermore, adiposity-related changes can influence tumour vascularity and inflammation in the tumour microenvironment, which can support tumour development and growth. Trials investigating non-pharmacological approaches to target the mechanisms driving obesity-mediated cancer pathogenesis are emerging and are necessary to better appreciate the interplay between malignancy, adiposity, diet and exercise. Diet, exercise and bariatric surgery are potential strategies to reverse the cancer-promoting effects of obesity; trials of these interventions should be conducted in a scientifically rigorous manner with dose escalation and appropriate selection of tumour phenotypes and have cancer-related clinical and mechanistic endpoints. We are only beginning to understand the mechanisms by which obesity effects cell signalling and systemic factors that contribute to oncogenesis. As the rates of obesity and cancer increase, we must promote the development of non-pharmacological lifestyle trials for the treatment and prevention of malignancy.

Utilizing the ABC Transporter for Growth Factor Production by fleQ Deletion Mutant of Pseudomonas fluorescens

Pseudomonas fluorescens, a gram-negative bacterium, has been proven to be a capable protein manufacturing factory (PMF). Utilizing its ATP-binding cassette (ABC) transporter, a type I secretion system, P. fluorescens has successfully produced recombinant proteins. However, besides the target proteins, P. fluorescens also secretes unnecessary background proteins that complicate protein purification and other downstream processes. One of the background proteins produced in large amounts is FliC, a flagellin protein. In this study, the master regulator of flagella gene expression, fleQ, was deleted from P. fluorescens Δtp, a lipase and protease double-deletion mutant, via targeted gene knockout. FleQ directs flagella synthesis, so the new strain, P. fluorescens ΔfleQ, does not produce flagella-related proteins. This not only simplifies purification but also makes P. fluorescens ΔfleQ an eco-friendly expression host because it will not survive outside a controlled environment. Six recombinant growth factors, namely, insulin-like growth factors I and II, beta-nerve growth factor, fibroblast growth factor 1, transforming growth factor beta, and tumor necrosis factor beta, prepared using our supercharging method, were successfully secreted by P. fluorescens ΔfleQ. Our findings demonstrate the potential of P. fluorescens ΔfleQ, combined with our supercharging process, as a PMF.

Insulin-like growth factor 2 (IGF2) expression in adrenocortical disease due to PRKAR1A mutations compared to other benign adrenal tumors

PURPOSE

Insulin-like growth factor-II (IGF2), a key regulator of cell growth and development, is tightly regulated in its expression by epigenetic control that maintains its monoallelic expression in most tissues. Biallelic expression of IGF2 resulting from loss of imprinting (LOI) has been reported in adrenocortical tumors. In this study, we wanted to check whether adrenocortical lesions due to PRKAR1A mutations lead to increased IGF2 expression from LOI and compare these findings to those in other benign adrenal lesions.

METHODS

We compared the expression of IGF2 by RNA and protein studies in primary pigmented nodular adrenocortical disease (PPNAD) caused by PRKAR1A gene mutations to that in primary macronodular adrenocortical hyperplasia (PMAH) and cortisol-producing adenomas (CPA) that did not have any mutations in known genes. We also checked LOI in all lesions by DNA allelic studies and the expression of other components of IGF2 signaling at the RNA and protein level.

RESULTS

We identified cell clusters overexpressing IGF2 in PPNAD; although immunostaining was patchy, overall, by RNA and immunoblotting PPNAD expressed high IGF2 message and protein. However, this was not due to LOI, as there was no correlation between IGF2 expression and the presence of LOI.

CONCLUSIONS

Our data pointed to over-expression of IGF2 protein in PPNAD compared to other benign adrenocortical lesions, such as PMAH and CPA. However, there was no correlation of IGF2 mRNA levels with LOI of IGF2/H19. The discrepancy between mRNA and protein levels with regards to LOI points, perhaps, to different control of IGF2 gene expression in PPNAD.

Insulin-Like Growth Factor-II and Ischemic Stroke-A Prospective Observational Study

Insulin-like growth factor-II (IGF-II) regulates prenatal brain development, but the role in adult brain function and injury is unclear. Here, we determined whether serum levels of IGF-II (s-IGF-II) are associated with mortality and functional outcome after ischemic stroke (IS). The study population comprised ischemic stroke cases (n = 492) and controls (n = 514) from the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). Functional outcome was evaluated after 3 months and 2 years using the modified Rankin Scale (mRS), and additionally, survival was followed at a minimum of 7 years or until death. S-IGF-II levels were higher in IS cases both in the acute phase and at 3-month follow-up compared to controls (p < 0.05 and p < 0.01, respectively). The lowest quintile of acute s-IGF-II was, compared to the four higher quintiles, associated with an increased risk of post-stroke mortality (median follow-up 10.6 years, crude hazard ratio (HR) 2.34, 95% confidence interval (CI) 1.56–3.49, and fully adjusted HR 1.64, 95% CI 1.02–2.61). In contrast, crude associations with poor functional outcome (mRS 3–6) lost significance after full adjustment for covariates. In conclusion, s-IGF-II was higher in IS cases than in controls, and low acute s-IGF-II was an independent risk marker of increased mortality.

The ER Chaperones BiP and Grp94 Regulate the Formation of Insulin-Like Growth Factor 2 (IGF2) Oligomers

While cytosolic Hsp90 chaperones have been extensively studied, less is known about how the ER Hsp90 paralog Grp94 recognizes clients and influences client folding. Here, we examine how Grp94 and the ER Hsp70 paralog, BiP, influence the folding of insulin-like growth factor 2 (IGF2), an established client protein of Grp94. ProIGF2 is composed of a disulfide-bonded insulin-like hormone and a C-terminal E-peptide that has sequence characteristics of an intrinsically disordered region. BiP and Grp94 have a minimal influence on folding whereby both chaperones slow proIGF2 folding and do not substantially alter the disulfide-bonded folding intermediates, suggesting that BiP and Grp94 may have an additional influence unrelated to proIGF2 folding. Indeed, we made the unexpected discovery that the E-peptide region allows proIGF2 to form dynamic oligomers. ProIGF2 oligomers can transition from a dynamic state that is capable of exchanging monomers to an irreversibly aggregated state, providing a plausible role for BiP and Grp94 in regulating proIGF2 oligomerization. In contrast to the modest influence on folding, BiP and Grp94 have a stronger influence on proIGF2 oligomerization and these chaperones exert counteracting effects. BiP suppresses proIGF2 oligomerization while Grp94 can enhance proIGF2 oligomerization in a nucleotide-dependent manner. We propose that BiP and Grp94 regulate the assembly and dynamic behavior of proIGF2 oligomers, although the biological role of proIGF2 oligomerization is not yet known.

Lessons Learned from Targeting IGF-I Receptor in Thyroid-Associated Ophthalmopathy

Complex immunological mechanisms underlie the pathogenesis of thyroid-associated ophthalmopathy (TAO). Historical models of Graves’ disease and TAO have focused almost entirely on autoimmune reactivity directed against the thyrotropin receptor (TSHR). The insulin-like growth factor-I receptor (IGF-IR) has been proposed as a second participating antigen in TAO by virtue of its interactions with IGFs and anti-IGF-IR antibodies generated in Graves’ disease. Furthermore, the IGF-IR forms with TSHR a physical and functional complex which is involved in signaling downstream from both receptors. Inhibition of IGF-IR activity results in attenuation of signaling initiated at either receptor. Based on the aggregate of findings implicating IGF-IR in TAO, the receptor has become an attractive therapeutic target. Recently, teprotumumab, a human monoclonal antibody IGF-IR inhibitor was evaluated in two clinical trials of patients with moderate to severe, active TAO. Those studies revealed that teprotumumab was safe and highly effective in reducing disease activity and severity. Targeting IGF-IR with specific biologic agents may result in a paradigm shift in the therapy of TAO.

Investigating IGF-II and IGF2R serum markers as predictors of body weight loss following an 8-week acute weight loss intervention: PREVIEW sub-study

BACKGROUND

Weight reduction is effective in preventing T2D however, weight reduction and maintenance is difficult to achieve on a population scale. Serum insulin-like growth factor II (IGF-II) and IGF-II receptor (IGF2R) have been associated with diabetic status and body weight in prior studies and, in addition, IGF-II has been indicated as predictive of future weight change. We measured these serum markers in participants with obesity/overweight and prediabetes from the New Zealand arm of the PREVIEW lifestyle intervention randomised trial before and after an 8-week low energy diet (LED).

METHODS

Total IGF-II (n = 223) and soluble IGF2R (n = 151) were measured using commercial ELISA kits on fasted serum samples taken prior to an 8-week LED and also from participants completing the LED.

RESULTS

IGF-II levels were not correlated with baseline body weight although mean levels did significantly decrease following the LED. Change in IGF-II serum level was correlated to fasting glucose change (p = 0.04) but not to weight change. Baseline serum IGF2R was correlated with BMI (p = 0.007) and was significantly higher in Māori compared to European Caucasian participants independent of body weight (p = 0.0016). Following LED, IGF2R change was positively associated with weight change (p = 0.02) when corrected for ethnicity. Pre-LED levels of these serum markers were not predictive of the magnitude of weight loss over the 8 weeks.

CONCLUSION

Neither marker was useful in predicting magnitude of short-term weight loss. IGF2R is positively associated with BMI and is higher in Māori compared to European Caucasian individuals.

Identification of core miRNAs and regulatory pathways in breast cancer by integrated bioinformatics analysis

Breast cancer (BC) ranks first among malignancies in the female population due to its complicated pathological progression and poor prognosis. Hence, the aim of the present study was to identify potential molecular prognostic biomarkers able to predict the prognosis of BC patients. We integrated two microRNA (miRNA) expression microarrays and three gene microarrays related to BC from the NCBI Gene Expression Comprehensive (GEO) database to screen for differentially expressed miRNAs and identify their regulatory networks. The Kaplan-Meier plotter online analysis tool was used to assess the overall survival value of miRNAs expression in BC patients. The LinkedOmics online tool was used to analyze genes correlated with miRNAs expression. To clarify the upstream regulation mechanism of genes, we used ChIP-Atlas to identify and screen for transcription factors and visually verify them using the Integrative Genomics Viewer. To further analyze the downstream regulatory mechanism of miRNA in BC, we verified differentially expressed genes (DEGs) correlated to miRNAs in three GEO gene microarrays and the gene set predicted by miRWalk. The open access Metascape program allowed analysis of Gene Ontology (GO) processes, KEGG pathways and GO enrichment was performed on the DEGs. To further identify hub genes, Cytoscape software and its plug-in were applied to construct protein-protein interaction networks. In the present study, several possible molecules and related pathways related to miR-483 were identified by bioinformatics analysis. These molecules and pathways might represent key mechanisms involved in BC progression and development. This work provides a novel view and insight in the pathogenesis, treatment and prognosis for BC.

Insulin-like growth factor 2 is produced by antral follicles and promotes preantral follicle development in macaques†

Insulin-like growth factors (IGFs) are known for their involvement in endocrine and paracrine regulation of ovarian function. Although IGF2 is the predominant circulating and intraovarian form of IGFs in primate species, the stage-specific follicular expression, action, and regulation of IGF2 are not well defined. Therefore, experiments were conducted to investigate the follicular IGF production in response to steroid hormone regulation and the direct IGF actions on follicular development and function in vitro. Preantral follicles were isolated from rhesus macaque ovaries and cultured to the antral stage in media supplemented with follicle-stimulating hormone and insulin. Follicles were randomly assigned to treatment groups: (a) control, (b) trilostane (a steroid synthesis inhibitor), (c) trilostane + estradiol, (d) trilostane + progesterone, and (e) trilostane + dihydrotestosterone. Media was analyzed for IGF concentrations, which were correlated to follicle growth. Follicles produced IGF2, but not IGF1, at the antral stage. Steroid depletion decreased, whereas steroid replacement increased, IGF2 production by antral follicles. Media IGF2 levels correlated positively with antral follicle diameters. Macaque preantral follicles and granulosa cells were subsequently cultured without (control) and with recombinant human IGF2 supplementation. Follicle survival, growth, and paracrine factor production, as well as granulosa cell proliferation and gonadotropin receptor gene expression, were assessed. IGF2 addition increased follicle survival rates, diameters and inhibin B production, as well as granulosa cell proliferation. These data demonstrate that IGF2 produced by antral follicles, in response to steroid hormone regulation, could act as a paracrine factor that positively impacts preantral follicle development and function in primates.

Regulation of Fetal Genes by Transitions among RNA-Binding Proteins during Liver Development

Transcripts of alpha-fetoprotein (Afp), H19, and insulin-like growth factor 2 (Igf2) genes are highly expressed in mouse fetal liver, but decrease drastically during maturation. While transcriptional regulation of these genes has been well studied, the post-transcriptional regulation of their developmental decrease is poorly understood. Here, we show that shortening of poly(A) tails and subsequent RNA decay are largely responsible for the postnatal decrease of Afp, H19, and Igf2 transcripts in mouse liver. IGF2 mRNA binding protein 1 (IMP1), which regulates stability and translation efficiency of target mRNAs, binds to these fetal liver transcripts. When IMP1 is exogenously expressed in mouse adult liver, fetal liver transcripts show higher expression and possess longer poly(A) tails, suggesting that IMP1 stabilizes them. IMP1 declines concomitantly with fetal liver transcripts as liver matures. Instead, RNA-binding proteins (RBPs) that promote RNA decay, such as cold shock domain containing protein E1 (CSDE1), K-homology domain splicing regulatory protein (KSRP), and CUG-BP1 and ETR3-like factors 1 (CELF1), bind to 3' regions of fetal liver transcripts. These data suggest that transitions among RBPs associated with fetal liver transcripts shift regulation from stabilization to decay, leading to a postnatal decrease in those fetal transcripts.

Allosteric regulation of lysosomal enzyme recognition by the cation-independent mannose 6-phosphate receptor

The cation-independent mannose 6-phosphate receptor (CI-MPR, IGF2 receptor or CD222), is a multifunctional glycoprotein required for normal development. Through the receptor's ability to bind unrelated extracellular and intracellular ligands, it participates in numerous functions including protein trafficking, lysosomal biogenesis, and regulation of cell growth. Clinically, endogenous CI-MPR delivers infused recombinant enzymes to lysosomes in the treatment of lysosomal storage diseases. Although four of the 15 domains comprising CI-MPR's extracellular region bind phosphorylated glycans on lysosomal enzymes, knowledge of how CI-MPR interacts with ~60 different lysosomal enzymes is limited. Here, we show by electron microscopy and hydroxyl radical protein footprinting that the N-terminal region of CI-MPR undergoes dynamic conformational changes as a consequence of ligand binding and different pH conditions. These data, coupled with X-ray crystallography, surface plasmon resonance and molecular modeling, allow us to propose a model explaining how high-affinity carbohydrate binding is achieved through allosteric domain cooperativity.

Insulin-like growth factor-II and bioactive proteins containing a part of the E-domain of pro-insulin-like growth factor-II

Insulin-like growth factor (IGF)-II is considered to function as an important fetal growth factor, which is structurally and functionally related to IGF-I and proinsulin. At least in vitro, IGF-II actions are mediated through the IGF-I receptor and to a lesser extent the insulin receptor. After birth, the function of IGF-II is less clear although in adults the serum level of IGF-II exceeds that of IGF-I several fold. The IGF-II gene is maternally imprinted, with exception of the liver and several parts of the brain, where it is expressed from both alleles. The regulation, organization, and translation of the IGF-II gene is complex, with five different putative promotors leading to a range of noncoding and coding mRNAs. The 180-amino acid pre-pro-IGF-II translation product can be divided into five domains and include a N-terminal signal peptide of 24 amino acid residues, the 67 amino acid long mature protein, and an 89 residues extension at the COOH terminus, designated as the E-domain. After removal of the signal peptide, the processing of pro-IGF-II into mature IGF-II requires various steps including glycosylation of the E-domain followed by the action of endo-proteases. Several of these processing intermediates can be found in the human circulation. There is increasing evidence that, besides IGF-II, several incompletely processed precursor forms of the protein, and even a 34-amino acid peptide (preptin) derived from the E-domain of pro-IGF-II, exhibit distinct biological activities. This review will focus on the current insights regarding the specific roles of the latter proteins in cancer, glucose homeostasis, and bone physiology. To address this topic clearly in the right context, a concise overview of the biological and biochemical properties of IGF-II and several relevant aspects of the IGF system will be provided.

Contribution of gene mutations to Silver-Russell syndrome phenotype: multigene sequencing analysis in 92 etiology-unknown patients

BACKGROUND

Silver-Russell syndrome (SRS) is characterized by growth failure and dysmorphic features. Major (epi)genetic causes of SRS are loss of methylation on chromosome 11p15 (11p15 LOM) and maternal uniparental disomy of chromosome 7 (upd(7)mat). However, IGF2, CDKN1C, HMGA2, and PLAG1 mutations infrequently cause SRS. In addition, other imprinting disturbances, pathogenic copy number variations (PCNVs), and monogenic disorders sometimes lead to SRS phenotype. This study aimed to clarify the frequency and clinical features of the patients with gene mutations among etiology-unknown patients with SRS phenotype.

RESULTS

Multigene sequencing was performed in 92 out of 336 patients referred to us for genetic testing for SRS. The clinical features of the patients were evaluated based on the Netchine-Harbison clinical scoring system. None of the patients showed 11p15 LOM, upd(7)mat, abnormal methylation levels for six differentially methylated regions (DMRs), namely, PLAGL1:alt-TSS-DMR on chromosome 6, KCNQ1OT1:TSS-DMR on chromosome 11, MEG3/DLK1:IG-DMR on chromosome 14, MEG3:TSS-DMR on chromosome 14, SNURF:TSS-DMR on chromosome 15, and GNAS A/B:TSS-DMR on chromosome 20, PCNVs, or maternal uniparental disomy of chromosome 16. Using next-generation sequencing and Sanger sequencing, we screened four SRS-causative genes and 406 genes related to growth failure and/or skeletal dysplasia. We identified four pathogenic or likely pathogenic variants in responsible genes for SRS (4.3%: IGF2 in two patients, CDKN1C, and PLAG1), and five pathogenic variants in causative genes for known genetic syndromes presenting with growth failure (5.4%: IGF1R abnormality (IGF1R), SHORT syndrome (PIK3R1), Floating-Harbor syndrome (SRCAP), Pitt-Hopkins syndrome (TCF4), and Noonan syndrome (PTPN11)). Functional analysis indicated the pathogenicity of the CDKN1C variant. The variants we detected in CDKN1C and PLAG1 were the second and third variants leading to SRS, respectively. Our patients with CDKN1C and PLAG1 variants showed similar phenotypes to previously reported patients. Furthermore, our data confirmed IGF1R abnormality, SHORT syndrome, and Floating-Harbor syndrome are differential diagnoses of SRS because of the shared phenotypes among these syndromes and SRS. On the other hand, the patients with pathogenic variants in causative genes for Pitt-Hopkins syndrome and Noonan syndrome were atypical of these syndromes and showed partial clinical features of SRS.

CONCLUSIONS

We identified nine patients (9.8%) with pathogenic or likely pathogenic variants out of 92 etiology-unknown patients with SRS phenotype. This study expands the molecular spectrum of SRS phenotype.

IGF2 Mutations

OBJECTIVE

IGF2 is a paternally expressed growth-promoting gene. Here, we report five cases with IGF2 mutations and review IGF2 mutation-positive patients described in the literature. We also compare clinical features between patients with IGF2 mutations and those with H19/IGF2:IG-DMR epimutations.

RESULTS

We recruited five cases with IGF2 mutations: case 1 with a splice site mutation (c.-6-1G>C) leading to skipping of exon 2 and cases 2-5 with different missense mutations (p.(Cys70Tyr), p.(Cys71Arg), p.(Cys33Ser), and p.(Cys45Ser)) affecting cysteine residues involved in the S-S bindings. All the mutations resided on the paternally inherited allele, and the mutation of case 5 was present in a mosaic condition. Clinical assessment revealed Silver-Russell syndrome (SRS) phenotype with Netchine-Harbison scores of ≥5/6 in all the apparently nonmosaic 14 patients with IGF2 mutations (cases 1-4 described in this study and 10 patients reported in the literature). Furthermore, compared with H19/IGF2:IG-DMR epimutations, IGF2 mutations were associated with low frequency of hemihypoplasia, high frequency of feeding difficulty and/or reduced body mass index, and mild degree of relative macrocephaly, together with occasional development of severe limb malformations, high frequency of cardiovascular anomalies and developmental delay, and low serum IGF-II values.

CONCLUSIONS

This study indicates that IGF2 mutations constitute a rare but important cause of SRS. Furthermore, while both IGF2 mutations and H19/IGF2:IG-DMR epimutations lead to SRS, a certain degree of phenotypic difference is observed between the two groups, probably due to the different IGF2 expression pattern in target tissues.

Genetic Associations with Aging Muscle: A Systematic Review

The age-related decline in skeletal muscle mass, strength and function known as 'sarcopenia' is associated with multiple adverse health outcomes, including cardiovascular disease, stroke, functional disability and mortality. While skeletal muscle properties are known to be highly heritable, evidence regarding the specific genes underpinning this heritability is currently inconclusive. This review aimed to identify genetic variants known to be associated with muscle phenotypes relevant to sarcopenia. PubMed, Embase and Web of Science were systematically searched (from January 2004 to March 2019) using pre-defined search terms such as "aging", "sarcopenia", "skeletal muscle", "muscle strength" and "genetic association". Candidate gene association studies and genome wide association studies that examined the genetic association with muscle phenotypes in non-institutionalised adults aged ≥50 years were included. Fifty-four studies were included in the final analysis. Twenty-six genes and 88 DNA polymorphisms were analysed across the 54 studies. The ACTN3, ACE and VDR genes were the most frequently studied, although the IGF1/IGFBP3, TNFα, APOE, CNTF/R and UCP2/3 genes were also shown to be significantly associated with muscle phenotypes in two or more studies. Ten DNA polymorphisms (rs154410, rs2228570, rs1800169, rs3093059, rs1800629, rs1815739, rs1799752, rs7412, rs429358 and 192 bp allele) were significantly associated with muscle phenotypes in two or more studies. Through the identification of key gene variants, this review furthers the elucidation of genetic associations with muscle phenotypes associated with sarcopenia.

Diagnostic and clinical utility of whole genome sequencing in a cohort of undiagnosed Chinese families with rare diseases

Rare diseases are usually chronically debilitating or even life-threatening with diagnostic and therapeutic challenges in current clinical practice. It has been estimated that 80% of rare diseases are genetic in origin, and thus genome sequencing-based diagnosis offers a promising alternative for rare-disease management. In this study, 79 individuals from 16 independent families were performed for whole-genome sequencing (WGS) in an effort to identify the causative mutations for 16 distinct rare diseases that are largely clinically intractable. Comprehensive analysis of variations, including simple nucleotide variants (SNVs), copy-number variations (CNVs), and structural variations (SVs), was implemented using the WGS data. A flexible analysis pipeline that allowed a certain degree of misclassification of disease status was developed to facilitate the identification of causative variants. As a result, disease-causing variants were identified in 10 of the 16 investigated diseases, yielding a diagnostic rate of 62.5%. Additionally, new potentially pathogenic variants were discovered for two disorders, including IGF2/INS-IGF2 in mitochondrial disease and FBN3 in Klippel–Trenaunay–Weber syndrome. Our WGS analysis not only detected a CNV associated with 3p deletion syndrome but also captured a simple sequence repeat (SSR) variation associated with Machado–Joseph disease. To our knowledge, this is the first time the clinical WGS analysis of short-read sequences has been used successfully to identify a causative SSR variation that perfectly segregates with a repeat expansion disorder. After the WGS analysis, we confirmed the initial diagnosis for three of 10 established disorders and modified or corrected the initial diagnosis for the remaining seven disorders. In summary, clinical WGS is a powerful tool for the diagnosis of rare diseases, and its diagnostic clarity at molecular levels offers important benefits for the participating families.

Insulin-Like Growth Factor 2 (IGF2) Signaling in Colorectal Cancer-From Basic Research to Potential Clinical Applications

Colorectal cancer (CRC) is one of the most common cancers in men and women worldwide as well as is the leading cause of death in the western world. Almost a third of the patients has or will develop liver metastases. While genetic as well as epigenetic mechanisms are important in CRC pathogenesis, the basis of the most cases of cancer is unknown. High spatial and inter-patient variability of the molecular alterations qualifies this cancer in the group of highly heterogeneous tumors, which makes it harder to elucidate the mechanisms underlying CRC progression. Determination of highly sensitive and specific early diagnosis markers and understanding the cellular and molecular mechanism(s) of cancer progression are still a challenge of the current era in oncology of solid tumors. One of the accepted risk factors for CRC development is overexpression of insulin-like growth factor 2 (IGF2), a 7.5-kDa peptide produced by liver and many other tissues. IGF2 is the first gene discovered to be parentally imprinted. Loss of imprinting (LOI) or aberrant imprinting of IGF2 could lead to IGF2 overexpression, increased cell proliferation, and CRC development. IGF2 as a mitogen is associated with increased risk of developing colorectal neoplasia. Higher serum IGF2 concentration as well as its tissue overexpression in CRC compared to control are associated with metastasis. IGF2 protein was one of the three candidates for a selective marker of CRC progression and staging. Recent research indicates dysregulation of different micro- and long non-coding RNAs (miRNAs and lncRNAs, respectively) embedded within the IGF2 gene in CRC carcinogenesis, with some of them indicated as potential diagnostic and prognostic CRC biomarkers. This review systematises the knowledge on the role of genetic and epigenetic instabilities of IGF2 gene, free (active form of IGF2) and IGF-binding protein (IGFBP) bound (inactive form), paracrine/autocrine secretion of IGF2, as well as mechanisms of inducing dysplasia in vitro and tumorigenicity in vivo. We have tried to answer which molecular changes of the IGF2 gene and its regulatory mechanisms have the most significance in initiation, progression (including liver metastasis), prognosis, and potential anti-IGF2 therapy in CRC patients.

Combined effect between WT1 methylation and Helicobacter pylori infection, smoking, and alcohol consumption on the risk of gastric cancer

BACKGROUND

Peripheral blood leukocyte DNA methylation status has been proposed to be a surrogate marker for evaluating susceptibility to gastric cancer (GC). Helicobacter pylori (H pylori) infection, smoking, and alcohol consumption are known to induce gene methylation. A case-control study was performed to investigate the interactions between the methylation of two candidate genes and H pylori infection, smoking, and alcohol consumption in the risk of GC.

METHODS

A total of 400 GC cases and 402 controls were included in this study. The methylation status of WT1 and IGF2 was semiquantitatively determined by using methylation-sensitive high-resolution melting assays. H pylori IgG antibodies were detected by ELISA method.

RESULTS

Based on the area under the curve (AUC), 0% methylated DNA and 0.5% methylated DNA were used as the cutoff values for WT1 and IGF2, respectively. WT1 methylation was significantly associated with increased GC risk (OR = 1.65, 95% CI = 1.09-2.51, P = .019), especially in males (OR = 1.80, 95% CI: 1.10-2.95, P = .019) and older individuals (≥60 years) (OR = 2.03, 95% CI: 1.15-3.57, P = .014). A significant combination was observed between WT1 methylation and H pylori infection, alcohol consumption, and smoking for the risk of GC (OR_c  = 2.28, 95% CI = 1.47-3.55, P = .003, OR_c  = 2.19, 95% CI = 1.37-3.51, P = .001, OR_c  = 2.21, 95% CI = 1.39-3.51, P = .001, respectively). However, no association between IGF2 methylation and the risk of GC was found in this study.

CONCLUSIONS

WT1 methylation may serve as a new potential biomarker for GC susceptibility and can combine with H pylori infection, smoking, and alcohol consumption to influence GC risk.

Non-islet cell tumour hypoglycaemia in a patient with a well-differentiated gastric neuroendocrine tumour

A 61-year-old man, without noteworthy medical history, presented with complaints of progressive fatigue and flushes. Diagnostic imaging revealed a large tumour in the stomach with liver metastases, and histopathological examination showed a well-differentiated gastric neuroendocrine tumour (NET). After chemotherapy, everolimus was administered, and upon progression, PD-1 inhibitor PDR001 was started. Two weeks after the first gift, he was admitted with loss of consciousness and a blood glucose level of 1.6 mmol/L. Plasma insulin was below 0.5 mU/L, C-peptide level was 250 pmol/L, insulin-like growth factor (IGF)-II was 804 ng/mL, and pro-IGF-IIE level was 80 µg/L. Based on the clinical findings, the patient was diagnosed with non-islet cell tumour hypoglycaemia (NICTH) with an overproduction of pro-IGF-IIE and eventually IGF-II due to progressive metastatic well-differentiated gastric NET. NICTH is a very rare condition. It has been reported in several tumour types but has never been described as a consequence of NET.

A novel epitope-presenting thermostable scaffold for the development of highly specific insulin-like growth factor-1/2 antibodies

High sequence and structural homology between mature human insulin-like growth factors IGF-1 and IGF-2 makes serological discrimination by immunodiagnostic IGF tests a challenging task. There is an urgent need for highly specific IGF-1 and IGF-2 antibodies, yet only a short sequence element, i.e. the IGF loop, provides enough difference in sequence to discriminate between the two molecules. We sought to address this unmet demand by investigating novel chimeric immunogens as carriers for recombinant peptide motif grafting. We found Thermus thermophilus sensitive to lysis D (SlyD) and Thermococcus gammatolerans SlyD FK-506–binding protein (FKBP) domains suitable for presentation of the predefined epitopes, namely the IGF-1 and IGF-2 loops. Chimeric SlyD-IGF proteins allowed for the development of exceptionally specific IGF-1 and IGF-2 monoclonal antibodies. The selected antibodies bound with high affinity to the distinct IGF epitopes displayed on the protein scaffolds, as well as on the mature human IGF isoforms. The respective SlyD scaffolds display favorable engineering properties in that they are small, monomeric, and cysteine-free and can be produced in high yields in a prokaryotic host, such as Escherichia coli. In conclusion, FKBP domains from thermostable SlyD proteins are highly suitable as a generic scaffold platform for epitope grafting.

The PLAG1 mRNA expression analysis among genetic variants and relevance to growth traits in Chinese cattle

Pleomorphic adenoma gene 1 (PLAG1) encodes a developmentally regulated zinc finger protein, locating in growth-related QTNs. The mRNA expression of this gene was investigated in different tissues and from two different developmental periods, whilst to explore the functions of PLAG1 in growth traits of cattle. The results showed that PLAG1 was expressed in all examined tissues. However, PLAG1 expression levels in all examined tissues were significantly different between the 5-month fetus and 36-month adult cattle. Our juvenile results indicated PLAG1 is primarily expressed in embryonic tissues of Chinese cattle. Furthermore, two variations were identified. Association analysis revealed that the two variations were associated with growth traits (p < 0.05 or p < 0.01). These new findings provide a comprehensive overview of the critical roles of PLAG1 in growth traits modulation and can be highlighted as candidate molecular markers in cattle breeding.

Intraoperative glycemic control using an artificial endocrine pancreas in a patient with a recurrent pleural solitary fibrous tumor producing insulin-like growth factor 2: a case report

Background

Non-islet cell tumor producing insulin-like growth factor 2 involves hypoglycemia. During tumor resection, intense fluctuation of blood glucose level may occur. An artificial endocrine pancreas has been reported as beneficial for patients with insulinoma as it maintains stable glycemic levels, although scarcely described with insulin-like growth factor 2-releasing tumor.

Case presentation

An 84-year-old man had a recurrent left pleural solitary fibrous tumor releasing high molecular weight insulin-like growth factor 2 and experienced a frequent syncope accompanied by hypoglycemia. After anesthesia induction, an artificial endocrine pancreas, STG-55, was connected to the patient. Blood glucose level was stable at around 150 mg/dl during the resection surgery. The patient followed an uneventful course and was discharged without any complications.

Conclusions

An artificial endocrine pancreas may have the potential to stabilize the intraoperative blood glucose change in insulin-like growth factor 2-releasing tumor resection.

lncINS-IGF2 Promotes Cell Proliferation and Migration by Promoting G1/S Transition in Lung Cancer

Long noncoding RNAs are capable of regulating gene expression at multiple levels. These RNA molecules are also involved in a variety of physiological and pathological processes. Emerging data demonstrate that a series of differentially expressed long noncoding RNAs are implicated in tumorigenesis. In the present study, we used microarray analysis to identify long noncoding RNAs that are dysregulated in non-small-cell lung cancer when compared to normal lung tissues. Accordingly, we performed quantitative real-time polymerase chain reaction to analyze the levels of long noncoding RNA and the cis target gene. We further found the oncogene property of long noncoding RNA that long noncoding RNA downexpression inhibits non-small-cell lung cancer cells proliferation and migration based on 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and colony formation assays and wound healing as well as transwell assays. The influence of long noncoding RNA on cell cycle of non-small-cell lung cancer cells is also analyzed by flow cytometry. Among the dysregulated long noncoding RNAs, we identified INS-IGF2 readthrough, transcript variant 1, noncoding RNA (NR_003512.3) is upregulated in non-small-cell lung cancer tissues, the cis gene of which is insulin-like growth factor 2 gene hinted by bioinformatics analysis. We also observed that downregulation of INS-IGF2 readthrough, transcript variant 1, noncoding RNA reduces insulin-like growth factor 2 messenger RNA expression. Furthermore, INS-IGF2 readthrough, transcript variant 1, noncoding RNA downregulation suppresses non-small-cell lung cancer cell proliferation and migration. This downregulation results in a concomitant inhibition of the G1/S transition in non-small-cell lung cancer cells. Our findings suggest that INS-IGF2 readthrough, transcript variant 1, noncoding RNA may be an oncogene involved in the development of lung cancer. Therefore, we speculate that INS-IGF2 readthrough, transcript variant 1, noncoding RNA represents a potential therapeutic target for lung cancer.

From fever to immunity: A new role for IGFBP-6?

Fever is a fundamental response to infection and a hallmark of inflammatory disease, which has been conserved and shaped through millions of years of natural selection. Although fever is able to stimulate both innate and adaptive immune responses, the very nature of all the molecular thermosensors, the timing and the detailed mechanisms translating a physical trigger into a fundamental biological response are incompletely understood. Here we discuss the consequence of hyperthermic stress in dendritic cells (DCs), and how the sole physical input is sensed as an alert stimulus triggering a complex transition in a very narrow temporal window. Importantly, we review recent findings demonstrating the significant and specific changes discovered in gene expression and in the metabolic phenotype associated with hyperthermia in DCs. Furthermore, we discuss the results that support a model based on a thermally induced autocrine signalling, which rewires and sets a metabolism checkpoint linked to immune activation of dendritic cells. Importantly, in this context, we highlight the novel regulatory functions discovered for IGFBP‐6 protein: induction of chemotaxis; capacity to increase oxidative burst and degranulation of neutrophils, ability to induce metabolic changes in DCs. Finally, we discuss the role of IGFBP‐6 in autoimmune disease and how novel mechanistic insights could lead to exploit thermal stress‐related mechanisms in the context of cancer therapy.

DNA methylation pattern of bovine blastocysts associated with hyperinsulinemia in vitro

Insulin functions as a regulator of metabolism and plays an important role in reproduction. Hyperinsulinemia is often observed in patients with obesity and diabetes type 2 and is known to impair fertility, but the underlying molecular mechanisms are only partly understood. Metabolic programming through epigenetic mechanisms such as DNA methylation during embryonic development can lead to health implications for the offspring later in life. Our aim was to study the potential effect of hyperinsulinemia on gene expression and DNA methylation of embryos by adding insulin (0.1 µg/ml = INS0.1 or 10 µg/ml = INS10) during in vitro oocyte maturation by using the EmbryoGENE DNA methylation array for a study of the bovine epigenome. Our results showed significant differences between blastocysts originating from insulin-treated oocytes compared with untreated control blastocysts. In total, 13,658 and 12,418 probes were differentially methylated (DM) in INS0.1 and INS10, respectively, with an overlap of 3,233 probes in the DM regions (DMR) for both insulin groups. Genes related to pathways such as lipid metabolism, growth and proliferation, mitochondrial function, and oxidative stress responses were influenced at both the epigenetic and transcriptomic levels. In addition, imprinted genes and genes with functions in the epigenetic machinery were among the DMRs. This study identified DMRs correlated to differential expression of genes involved in metabolic regulation and should help to improve our knowledge of the underlying molecular mechanisms of metabolic imbalance.

Atlas of tissue- and developmental stage specific gene expression for the bovine insulin-like growth factor (IGF) system

The insulin-like growth factor (IGF) axis is fundamental for mammalian growth and development. However, no comprehensive reference data on gene expression across tissues and pre- and postnatal developmental stages are available for any given species. Here we provide systematic promoter- and splice variant specific information on expression of IGF system components in embryonic (Day 48), fetal (Day 153), term (Day 277, placenta) and juvenile (Day 365–396) tissues of domestic cow, a major agricultural species and biomedical model. Analysis of spatiotemporal changes in expression of IGF1, IGF2, IGF1R, IGF2R, IGFBP1-8 and IR genes, as well as lncRNAs H19 and AIRN, by qPCR, indicated an overall increase in expression from embryo to fetal stage, and decrease in expression from fetal to juvenile stage. The stronger decrease in expression of lncRNAs (average ―16-fold) and ligands (average ―12.1-fold) compared to receptors (average ―5.7-fold) and binding proteins (average ―4.3-fold) is consistent with known functions of IGF peptides and supports important roles of lncRNAs in prenatal development. Pronounced overall reduction in postnatal expression of IGF system components in lung (―12.9-fold) and kidney (―13.2-fold) are signatures of major changes in organ function while more similar hepatic expression levels (―2.2-fold) are evidence of the endocrine rather than autocrine/paracrine role of IGFs in postnatal growth regulation. Despite its rapid growth, placenta displayed a more stable expression pattern than other organs during prenatal development. Quantitative analyses of contributions of promoters P0-P4 to global IGF2 transcript in fetal tissues revealed that P4 accounted for the bulk of transcript in all tissues but skeletal muscle. Demonstration of IGF2 expression in fetal muscle and postnatal liver from a promoter orthologous to mouse and human promoter P0 provides further evidence for an evolutionary and developmental shift from placenta-specific P0-expression in rodents and suggests that some aspects of bovine IGF expression may be closer to human than mouse.

Insulin-like growth factors: actions on the skeleton

The discovery of the growth hormone (GH)-mediated somatic factors (somatomedins), insulin-like growth factor (IGF)-I and -II, has elicited an enormous interest primarily among endocrinologists who study growth and metabolism. The advancement of molecular endocrinology over the past four decades enables investigators to re-examine and refine the established somatomedin hypothesis. Specifically, gene deletions, transgene overexpression or more recently, cell-specific gene-ablations, have enabled investigators to study the effects of the Igf1 and Igf2 genes in temporal and spatial manners. The GH/IGF axis, acting in an endocrine and autocrine/paracrine fashion, is the major axis controlling skeletal growth. Studies in rodents have clearly shown that IGFs regulate bone length of the appendicular skeleton evidenced by changes in chondrocytes of the proliferative and hypertrophic zones of the growth plate. IGFs affect radial bone growth and regulate cortical and trabecular bone properties via their effects on osteoblast, osteocyte and osteoclast function. Interactions of the IGFs with sex steroid hormones and the parathyroid hormone demonstrate the significance and complexity of the IGF axis in the skeleton. Finally, IGFs have been implicated in skeletal aging. Decreases in serum IGFs during aging have been correlated with reductions in bone mineral density and increased fracture risk. This review highlights many of the most relevant studies in the IGF research landscape, focusing in particular on IGFs effects on the skeleton.

Tissue-specific and mosaic imprinting defects underlie opposite congenital growth disorders in mice

Differential DNA methylation defects of H19/IGF2 are associated with congenital growth disorders characterized by opposite clinical pictures. Due to structural differences between human and mouse, the mechanisms by which mutations of the H19/IGF2 Imprinting Control region (IC1) result in these diseases are undefined. To address this issue, we previously generated a mouse line carrying a humanized IC1 (hIC1) and now replaced the wildtype with a mutant IC1 identified in the overgrowth-associated Beckwith-Wiedemann syndrome. The new humanized mouse line shows pre/post-natal overgrowth on maternal transmission and pre/post-natal undergrowth on paternal transmission of the mutation. The mutant hIC1 acquires abnormal methylation during development causing opposite H19/Igf2 imprinting defects on maternal and paternal chromosomes. Differential and possibly mosaic Igf2 expression and imprinting is associated with asymmetric growth of bilateral organs. Furthermore, tissue-specific imprinting defects result in deficient liver- and placenta-derived Igf2 on paternal transmission and excessive Igf2 in peripheral tissues on maternal transmission, providing a possible molecular explanation for imprinting-associated and phenotypically contrasting growth disorders.

Insulin-Like Growth Factor (IGF) Binding Protein-2, Independently of IGF-1, Induces GLUT-4 Translocation and Glucose Uptake in 3T3-L1 Adipocytes

Insulin-like growth factor binding protein-2 (IGFBP-2) is the predominant IGF binding protein produced during adipogenesis and is known to increase the insulin-stimulated glucose uptake (GU) in myotubes. We investigated the IGFBP-2-induced changes in basal and insulin-stimulated GU in adipocytes and the underlying mechanisms. We further determined the role of insulin and IGF-1 receptors in mediating the IGFBP-2 and the impact of IGFBP-2 on the IGF-1-induced GU. Fully differentiated 3T3-L1 adipocytes were treated with IGFBP-2 in the presence and absence of insulin and IGF-1. Insulin, IGF-1, and IGFBP-2 induced a dose-dependent increase in GU. IGFBP-2 increased the insulin-induced GU after long-term incubation. The IGFBP-2-induced impact on GU was neither affected by insulin or IGF-1 receptor blockage nor by insulin receptor knockdown. IGFBP-2 significantly increased the phosphorylation of PI3K, Akt, AMPK, TBC1D1, and PKCζ/λ and induced GLUT-4 translocation. Moreover, inhibition of PI3K and AMPK significantly reduced IGFBP-2-stimulated GU. In conclusion, IGFBP-2 stimulates GU in 3T3-L1 adipocytes through activation of PI3K/Akt, AMPK/TBC1D1, and PI3K/PKCζ/λ/GLUT-4 signaling. The stimulatory effect of IGFBP-2 on GU is independent of its binding to IGF-1 and is possibly not mediated through the insulin or IGF-1 receptor. This study highlights the potential role of IGFBP-2 in glucose metabolism.

Vitrification, not cryoprotectant exposure, alters the expression of developmentally important genes in in vitro produced porcine blastocysts

The vitrification of embryos is common practice in advanced livestock breeding programs and in human fertility clinics. Recent studies have revealed that vitrification results in aberrant expression of a number of stress related genes. However, few studies have examined the effect that vitrification has on developmentally important genes, and none have been conducted in porcine embryos. The aim of this study was to determine the effects that different vitrification procedures and cryoprotectant combinations have on the expression of imprinted genes in in vitro produced (IVP) porcine blastocysts. The transcript levels of insulin-like growth factor 2 (IGF2) were lower in all groups of vitrified blastocysts compared to that in non-vitrified control blastocysts (P < 0.05). Expression levels of IGF2 and IGF2 receptor (IGF2R) in blastocysts that had been exposed to cryoprotectants without being vitrified were similar to that in non-vitrified control blastocysts (P > 0.05). Furthermore, blastocysts vitrified using ethylene glycol and propanediol combined, and those vitrified in a closed device, had IGF2R transcript levels similar to that in non-vitrified control blastocysts (P > 0.05). In conclusion, vitrification, but not exposure to cryoprotectants, caused aberrant expression of the imprinted genes IGF2 and IGF2R. Vitrification protocols that incorporated propanediol or a closed device were found to be least disruptive of gene expression in IVP porcine blastocysts.

Exploring evidence of positive selection signatures in cattle breeds selected for different traits

Since domestication, the genome landscape of cattle has been changing due to natural and artificial selection forces resulting in several general and specialized cattle breeds of the world. Identifying genomic regions affected due to these forces in livestock gives an insight into the history of selection for economically important traits and genetic adaptation to specific environments of the populations under consideration. This study explores the genes/genomic regions under selection in relation to the phenotypes of Holstein, Hanwoo, and N'Dama cattle breeds using Tajima's D, XP-CLR, and XP-EHH population statistical methods. The whole genomes of 10 Holstein (South Korea), 11 Hanwoo (South Korea), and 10 N'Dama (West Africa-Guinea) cattle breeds re-sequenced to ~11x coverage and retained 37 million SNPs were used for the study. Selection signature analysis revealed 441, 512, and 461 genes under selection from Holstein, Hanwoo, and N'Dama cattle breeds, respectively. Among all these, seven genes including ARFGAP3, SNORA70, and other RNA genes were common between the breeds. From each of the gene lists, significant functional annotation cluster terms including milk protein and thyroid hormone signaling pathway (Holstein), histone acetyltransferase activity (Hanwoo), and renin secretion (N'Dama) were enriched. Genes that are related to the phenotypes of the respective breeds were also identified. Moreover, significant breed-specific missense variants were identified in CSN3, PAPPA2 (Holstein), C1orf116 (Hanwoo), and COMMD1 (N'Dama) genes. The genes identified from this study provide an insight into the biological mechanisms and pathways that are important in cattle breeds selected for different traits of economic significance.