Overexpression Of Insulin-like Growth Factor Research Articles

Molecular characteristics and regulatory role of insulin-like growth factor 1 gene in testicular Leydig cells of Tibetan sheep.

This study aimed to analyze the molecular characteristics of insulin-like growth factor 1 (IGF1) gene in the testes of Tibetan sheep and its role in the testosterone synthesis and cell development. First, we cloned IGF1 gene for bioinformatics analysis, and the primary Leydig cells (LCs) of Tibetan sheep were isolated to explore its effect on the proliferation, apoptosis and function of LCs. Finally, the specific regulatory mechanism of IGF1 on LCs was analyzed by transcriptome sequencing. Results showed that overexpression of IGF1 increased the proliferation rate and decreased apoptosis of LCs. In addition, overexpression of IGF1 altered expression of genes related to testosterone synthesis and transformation and significantly increased amount of the final product testosterone. Mechanistically, IGF1 stimulated the expression of the proliferating cell nuclear antigen and IGF1R and promoted the proliferation of LCs via the PI3K/Akt signaling pathway. Collectively, what should be clear from the results reported here is that IGF1 might play roles in the proliferation or differentiation and testosterone synthesis of LCs. These findings add to our understanding on the regulation of testosterone synthesis in sheep and other mammals.

Pathways to precision medicine: deciphering the secrets of physiological and pathological atrial enlargement.

Cardiac functional, morphological, and histological analysis, coupled with liquid chromatography and mass spectrometry, of two transgenic mouse models with cardiomyocyte-specific overexpression of insulin-like growth factor 1 receptor (IGF1R) or a dominant-negative PI3K mutant (DCM-dnPI3K) revealed distinctive functional and molecular profiles during physiological (driven by IGF1R overexpression) and pathological (driven by dn-PI3K overexpression) atrial remodeling. The current study confirmed previously reported findings, including ventricular dilatation and enhanced systolic function with no evidence of arrhythmia in IGF1R model, as well as ventricular hypertrophy and decreased systolic function with intermittent atrial fibrillation in DCM-dnPI3K model. Novel findings obtained from the left atrial (LA) characterization of female mice revealed that physiological atrial enlargement resulted from increased atrial myocyte size and was associated with preserved atrial function, as determined by maintained LA ejection fraction (EF). The proteomic profile of IGF1R transgenic (Tg) mice was enriched for metabolic remodeling and showed a protein expression pattern similar to that of healthy human atria; on the other hand, pathological atrial enlargement resulted from increased atrial fibrosis with normal myocyte size and was associated with impaired atrial function due to a reduced LA EF. The proteomic profile of DCM-dnPI3K mice was enriched to both metabolic and structural remodeling and showed a protein expression pattern similar to that of human AF atria.

Insulin-like growth factor 2 targets IGF1R signaling transduction to facilitate metastasis and imatinib resistance in gastrointestinal stromal tumors

BACKGROUND Gastrointestinal stromal tumors (GISTs) are typical gastrointestinal tract neoplasms. Imatinib is the first-line therapy for GIST patients. Drug resistance limits the long-term effectiveness of imatinib. The regulatory effect of insulin-like growth factor 2 (IGF2) has been confirmed in various cancers and is related to resistance to chemotherapy and a worse prognosis. AIM To further investigate the mechanism of IGF2 specific to GISTs. METHODS IGF2 was screened and analyzed using Gene Expression Omnibus (GEO: GSE225819) data. After IGF2 knockdown or overexpression by transfection, the phenotypes (proliferation, migration, invasion, apoptosis) of GIST cells were characterized by cell counting kit 8, Transwell, and flow cytometry assays. We used western blotting to evaluate pathway-associated and epithelial-mesenchymal transition (EMT)-associated proteins. We injected transfected cells into nude mice to establish a tumor xenograft model and observed the occurrence and metastasis of GIST. RESULTS Data from the GEO indicated that IGF2 expression is high in GISTs, associated with liver metastasis, and closely related to drug resistance. GIST cells with high expression of IGF2 had increased proliferation and migration, invasiveness and EMT. Knockdown of IGF2 significantly inhibited those activities. In addition, OE-IGF2 promoted GIST metastasis in vivo in nude mice. IGF2 activated IGF1R signaling in GIST cells, and IGF2/IGF1R-mediated glycolysis was required for GIST with liver metastasis. GIST cells with IGF2 knockdown were sensitive to imatinib treatment when IGF2 overexpression significantly raised imatinib resistance. Moreover, 2-deoxy-D-glucose (a glycolysis inhibitor) treatment reversed IGF2 overexpression-mediated imatinib resistance in GISTs. CONCLUSION IGF2 targeting of IGF1R signaling inhibited metastasis and decreased imatinib resistance by driving glycolysis in GISTs.

Autocrine insulin-like growth factor 2 signaling as a potential target in the associated development of pulmonary emphysema and cancer in smokers

BackgroundTobacco smoking causes pulmonary inflammation, resulting in emphysema, an independent risk factor for lung cancer. Induction of insulin-like growth factor 2 (IGF2) in response to lung injury by tobacco carcinogens, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and polycyclic aromatic hydrocarbon benzo[a]pyrene in combination (NB), is critical for the proliferation of alveolar type 2 cells (AT2s) for lung repair. However, persistent IGF2 overexpression during NB-induced severe injury results in hyperproliferation of AT2s without coordinated AT2-to-AT1 differentiation, disrupting alveolar repair, which leads to the concurrent development of emphysema and lung cancer. The current study aims to verify the role of IGF2 signaling in the associated development of emphysema and cancer and develop effective pharmaceuticals for the diseases using animal models that recapitulate the characteristics of these chronic diseases.MethodsThe pathogenesis of pulmonary emphysema and cancer was analyzed by lung function testing, histological evaluation, in situ zymography, dihydroethidium staining, and immunofluorescence and immunohistochemistry analyses utilizing mouse models of emphysema and cancer established by moderate exposure to NB for up to seven months.ResultsModerate NB exposure induced IGF2 expression in AT2s during the development of pulmonary emphysema and lung cancer in mice. Using AT2-specific insulin receptor knockout mice, we verified the causative role of sustained IGF2 signaling activation in AT2s in emphysema development. IGF2-targeting strategies, including voltage-dependent calcium channel blocker (CCB) and a neutralizing antibody, significantly suppressed the NB-induced development of emphysema and lung cancer. A publicly available database revealed an inverse correlation between the use of calcium channel blockers and a COPD diagnosis.ConclusionsOur work confirms sustained IGF2 signaling activation in AT2s couples impaired lung repair to the concurrent development of emphysema and cancer in mice. Additionally, CCB and IGF2-specific neutralizing antibodies are effective pharmaceuticals for the two diseases.

Beckwith–Wiedemann syndrome with juvenile fibrous nodules and lobular breast tumors: a case report and review of the literature

BackgroundBeckwith–Wiedemann syndrome (BWS) is a genomic imprinting disorder caused by diverse genetic and/or epigenetic disorders of chromosome 11p15.5. BWS presents with a variety of clinical features, including overgrowth and an increased risk of embryonal tumors. Notably however, reports of patients with BWS and breast tumors are rare, and the association between these conditions is still unclear. Insulin-like growth factor-2 (IGF2) expression is known to be associated with the development of various cancers, including breast cancer, and patients with BWS with specific subtypes of molecular defects are known to show characteristic clinical features and IGF2 overexpression.Case presentationA 17-year-old girl who had been diagnosed with BWS based on an umbilical hernia, hyperinsulinemia, and left hemihypertrophy at birth, visited our department with a gradually swelling left breast. Her left breast was markedly larger than her right breast on visual examination. Imaging examinations showed two tumors measuring about 10 cm each in the left breast, and she was diagnosed with juvenile fibroadenoma following core needle biopsy. The two breast tumors were removed surgically and the patient remained alive with no recurrence. The final diagnosis was juvenile fibroadenoma without malignant findings. Immunohistochemical staining using IGF2 antibody revealed overexpression of IGF2 in the cytoplasm of ductal epithelial cells. Because of her clinical features and IGF2 overexpression, molecular defects of 11p15.5 including a possible genetic background of paternal uniparental disomy of chromosome 11 or hypermethylation of imprinting center 1 was suspected.ConclusionsIn this case, overexpression of IGF2 suggested a possible relationship between BWS and breast tumors. Moreover, the characteristic clinical features and IGF2 staining predicted the subtype of 11p15.5 molecular defects in this patient.

Locally Directed Recombinant Adeno- Associated Virus–Mediated IGF-1 Gene Therapy Enhances Osteochondral Repair and Counteracts Early Osteoarthritis In Vivo

Background: Restoration of osteochondral defects is critical, because osteoarthritis (OA) can arise. Hypothesis: Overexpression of insulin-like growth factor 1 (IGF-1) via recombinant adeno-associated viral (rAAV) vectors (rAAV-IGF-1) would improve osteochondral repair and reduce parameters of early perifocal OA in sheep after 6 months in vivo. Study Design: Controlled laboratory study. Methods: Osteochondral defects were created in the femoral trochlea of adult sheep and treated with rAAV-IGF-1 or rAAV-lacZ (control) (24 defects in 6 knees per group). After 6 months in vivo, osteochondral repair and perifocal OA were assessed by well-established macroscopic, histological, and immunohistochemical scoring systems as well as biochemical and micro–computed tomography evaluations. Results: Application of rAAV-IGF-1 led to prolonged (6 months) IGF-1 overexpression without adverse effects, maintaining a significantly superior overall cartilage repair, together with significantly improved defect filling, extracellular matrix staining, cellular morphology, and surface architecture compared with rAAV-lacZ. Expression of type II collagen significantly increased and that of type I collagen significantly decreased. Subchondral bone repair and tidemark formation were significantly improved, and subchondral bone plate thickness and subarticular spongiosa mineral density returned to normal. The OA parameters of perifocal structure, cell cloning, and matrix staining were significantly better preserved upon rAAV-IGF-1 compared with rAAV-lacZ. Novel mechanistic associations between parameters of osteochondral repair and OA were identified. Conclusion: Local rAAV-mediated IGF-1 overexpression enhanced osteochondral repair and ameliorated parameters of perifocal early OA. Clinical Relevance: IGF-1 gene therapy may be beneficial in repair of focal osteochondral defects and prevention of perifocal OA.

From Insight to Eyesight: Unveiling the Secrets of the Insulin-Like Growth Factor Axis in Retinal Health.

Insulin-like growth factor-1 (IGF-1) plays a diverse role in the retina, exerting its effects in both normal and diseased conditions. Deficiency of IGF-1 in humans leads to issues such as microcephaly, mental retardation, deafness, and postnatal growth failure. IGF-1 is produced in the retinal pigment epithelium (RPE) and activates the IGF-1 receptor (IGF-1R) in photoreceptor cells. When IGF-1R is absent in rod cells, it results in the degeneration of photoreceptors, emphasizing the neuroprotective function of IGF signaling in these cells. Contrastingly, in neovascular age-related macular degeneration (AMD), there is an overexpression of both IGF-1 and IGF-1R in RPE. The mechanisms behind this altered regulation of IGF-1 in diseased states are currently unknown. This comprehensive review provides recent insights into the role of IGF-1 in the health and disease of the retina, raising several unanswered questions that still need further investigation.

IGF2 prevents dopaminergic neuronal loss and decreases intracellular alpha-synuclein accumulation in Parkinson’s disease models

Parkinson’s disease (PD) is the second most common late-onset neurodegenerative disease and the predominant cause of movement problems. PD is characterized by motor control impairment by extensive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). This selective dopaminergic neuronal loss is in part triggered by intracellular protein inclusions called Lewy bodies, which are composed mainly of misfolded alpha-synuclein (α-syn) protein. We previously reported insulin-like growth factor 2 (IGF2) as a key protein downregulated in PD patients. Here we demonstrated that IGF2 treatment or IGF2 overexpression reduced the α-syn aggregates and their toxicity by IGF2 receptor (IGF2R) activation in cellular PD models. Also, we observed IGF2 and its interaction with IGF2R enhance the α-syn secretion. To determine the possible IGF2 neuroprotective effect in vivo we used a gene therapy approach in an idiopathic PD model based on α-syn preformed fibrils intracerebral injection. IGF2 gene therapy revealed a significantly preventing of motor impairment in idiopathic PD model. Moreover, IGF2 expression prevents dopaminergic neuronal loss in the SN together with a decrease in α-syn accumulation (phospho-α-syn levels) in the striatum and SN brain region. Furthermore, the IGF2 neuroprotective effect was associated with the prevention of synaptic spines loss in dopaminergic neurons in vivo. The possible mechanism of IGF2 in cell survival effect could be associated with the decrease of the intracellular accumulation of α-syn and the improvement of dopaminergic synaptic function. Our results identify to IGF2 as a relevant factor for the prevention of α-syn toxicity in both in vitro and preclinical PD models.

SAT174 Doege-Potter Syndrome In A Patient With Solitary Fibrous Tumor Of The Lung

Abstract Disclosure: N. Mon: None. S.S. Krishnasamy: None. Doege-Potter Syndrome is a non-islet cell tumor hypoglycemia (NICTH) due to a solitary fibrous tumor (SFT) with overexpression of Insulin-like growth factor 2 (IGF2). We report a case of refractory hypoglycemia in a patient with SFT of the lung. Case presentation: A 67-year-old homeless male with hypertension, chronic smoker presented with altered mental status after his blood glucose was found 34mg/dl by EMS. His confusion improved after D50W. He could not recall the event but he reported that he missed his dinner prior to the event. He denied taking any antidiabetic medications. He was diagnosed with left lung solitary fibrous tumor without metastases a week ago after he presented to ER with dyspnea, cough and wheezing. CT chest reported a 21x15.6x18.7 cm lesion with mass effect on the left hemidiaphragm, mediastinum shift to the right and occluded left lower lobe bronchi. Core needle biopsy of the mass revealed SFT with necrosis. He was discharged with Medrol dosepak 4mg daily for presumptive treatment of COPD exacerbation and a plan for elective surgery. While in the ER his BG improved to 136mg/dl after D50W. Few hours later BG dropped to 42mg/dl and D10W infusion was started. Physical exam was unremarkable except bilateral pedal edema. Work up showed BG 42mg/dl, Insulin 3.3 (2.6-24.9 uIU/mL), C peptide 0.39 (1.1-4.4ng/mL), Proinsulin 4.7 (<18.8pmol/L), beta-hydroxybutyrate <0.05 (0.02-0.27mmol/l), 8AM cortisol 10.7 (7.0-25.0 ug/dl), albumin 3.2mg/dl, HbA1c 5.8%, IGF1 53ng/mL (34-245ng/mL), IGF2 203ng/mL (267-616ng/mL) with a IGF2:IGF1 ratio of 3.8. In our patient, the IGF2:IGF1 ratio was not >10 since his IGF 2 was suppressed by the recent steroid use. The rest of the clinical and biochemical features strongly suggested NICTH. His preoperative evaluation showed new onset HFrEF with volume overload. He underwent staged percutaneous coronary interventions with stents placement. He was given hydrocortisone 50mg q6H then to q8H during hospitalization and discharged home with hydrocortisone 40mg TID. He underwent radical resection of lung tumor after optimization of his cardiac condition. He was on stress dose of steroid during surgery. Since he was on high dose steroid for > 3months, hydrocortisone dose was tapered slowly after the surgery. Final biopsy reported solitary fibrous tumor extending to parenchymal staple line. Tumor cells are positive for CD34 and STAT6, and negative for desmin, SMA, and SOX10. He recovered uneventfully and was discharged home with prednisone 5mg daily and follow up in endocrine clinic. Conclusion: NICTH is a rare paraneoplastic syndrome characterized by low levels of insulin, C-peptide, proinsulin, and beta-hydroxybutyrate. A ratio of IGF-2/IGF-1 more than 10 confirms NICTH; however, normal ratio cannot exclude the diagnosis and factors such as low IGFBP 3 or steroid therapy for other conditions need to be considered. Surgery is the mainstay of treatment. Presentation: Saturday, June 17, 2023

Circ-UBR4 regulates the proliferation, migration, inflammation, and apoptosis in ox-LDL-induced vascular smooth muscle cells via miR-515-5p/IGF2 axis.

The aim of our study is to disclose the role and underlying molecular mechanisms of circular RNA ubiquitin protein ligase E3 component n-recognin 4 (circ-UBR4) in atherosclerosis (AS). Our data showed that circ-UBR4 expression was upregulated in AS patients and oxidized low-density lipoprotein (ox-LDL)-induced vascular smooth muscle cells (VSMCs) compared with healthy volunteer and untreated VSMCs. In addition, ox-LDL stimulated proliferation, migration, and inflammation but decreased apoptosis in VSMCs, which were overturned by the inhibition of circ-UBR4. miR-515-5p was sponged by circ-UBR4, and its inhibitor reversed the inhibitory effect of circ-UBR4 knockdown on proliferation, migration, and inflammation in ox-LDL-induced VSMCs. Insulin-like growth factor2 (IGF2) was a functional target of miR-515-5p, and overexpression of IGF2 reversed the suppressive effect of miR-515-5p on ox-LDL-stimulated VSMCs proliferation, migration, and inflammation. Collectively, circ-UBR4 knockdown decreased proliferation, migration, and inflammation but stimulated apoptosis in ox-LDL-induced VSMCs by targeting the miR-515-5p/IGF2 axis.

Overexpression of IGF2 affects mouse weight and glycolipid metabolism and IGF2 is positively related to macrosomia.

To investigate the effects of insulin-like growth factor 2 (IGF2) on growth and glycolipid metabolism, as well as the underlying mechanism. A mouse model of IGF2 overexpression was constructed to measure weight gain before adulthood, to obtain the values of adult glycolipid metabolism indicators in the peripheral blood and to detect the expression of genes in the IGF2 signaling pathway in different mouse tissues. The present study also explored the independent association between the IGF2 gene and macrosomia by detecting and comparing the expression levels of IGF2 mRNA/H19 RNA in maternal peripheral blood and fetal cord blood of 26 human pregnancies. In the mouse model, weights of the IGF2-overexpressing mice were significantly higher than those of the control mice at the age of 5-10 weeks. The glucose concentration, total cholesterol and high-density lipoprotein cholesterol (HDL-C) levels of IGF2-overexpressing mice were significantly lower than those of wild-type (WT) mice. Compared with the WT mice, the expression of H19 was significantly decreased in the pancreas and IGF1R was significantly decreased in the muscle of mice with IGF2 overexpression. The expression levels of STAT3 and AKT2 showed significant decrease in liver, muscle and increase in muscle of IGF2-overexpressing mice, respectively. GLUT2 expression showed significant increase in liver, kidney, muscle and decrease in pancreas of mice with IGF2 overexpression. This study also found that in normal mothers with the similar clinical characteristics, IGF2 expression in the maternal peripheral blood and fetal cord blood is an independent factor influencing macrosomia. IGF2 expression was independently correlated with the occurrence of macrosomia, and overexpression of IGF2 significantly increased the weights of mice at the age of 5-10 weeks and significantly affected the values of adult glycolipid metabolism indicators, which might be the result of changes in the IGF2-IGF1R-STAT3/AKT2-GLUT2/GLUT4 pathway. These findings might suggest that IGF2 plays an important role in growth and glycolipid metabolism during both pregnancy and postnatal development.

IGF2 May Enhance Placental Fatty Acid Metabolism by Regulating Expression of Fatty Acid Carriers in the Growth of Fetus and Placenta during Late Pregnancy in Pigs.

Fatty acids (FAs) are essential substances for the growth and development of the fetus and placenta. The growing fetus and placenta must obtain adequate FAs received from the maternal circulation and facilitated by various placental FA carriers, including FA transport proteins (FATPs), FA translocase (FAT/CD36), and cytoplasmic FA binding proteins (FABPs). Placental nutrition transport was regulated by imprinted genes H19 and insulin-like growth factor 2 (IGF2). Nevertheless, the relationship between the expression patterns of H19/IGF2 and placental fatty acid metabolism throughout pig pregnancy remains poorly studied and unclear. We investigated the placental fatty acid profile, expression patterns of FA carriers, and H19/IGF2 in the placentae on Days 40 (D40), 65 (D65), and 95 (D95) of pregnancy. The results showed that the width of the placental folds and the number of trophoblast cells of D65 placentae were significantly increased than those of D40 placentae. Several important long-chain FAs (LCFAs), including oleic acid, linoleic acid, arachidonatic acid, eicosapentaenoic acid, and docosatetraenoic acid, in the pig placenta showed dramatically increased levels throughout pregnancy. The pig placenta possessed higher expression levels of CD36, FATP4, and FABP5 compared with other FA carriers, and their expression levels had significantly upregulated 2.8-, 5.6-, and 12.0-fold from D40 to D95, respectively. The transcription level of IGF2 was dramatically upregulated and there were corresponding lower DNA methylation levels in the IGF2 DMR2 in D95 placentae relative to D65 placentae. Moreover, in vitro experimentation revealed that the overexpression of IGF2 resulted in a significant increase in fatty acid uptake and expression levels of CD36, FATP4, and FABP5 in PTr2 cells. In conclusion, our results indicate that CD36, FATP4, and FABP5 may be important regulators that enhance the transport of LCFAs in the pig placenta and that IGF2 may be involved in FA metabolism by affecting the FA carriers expression to support the growth of the fetus and placenta during late pregnancy in pigs.

Cardiac-specific overexpression of insulin-like growth factor II receptor-α interferes with the regulation of calcium homeostasis in the heart under hyperglycemic conditions.

Diabetic cardiomyopathy is a progressive disease caused by inexplicit mechanisms, and a novel factor, insulin-like growth factor II receptor-α (IGF-IIRα), may contribute to aggravating its pathogenesis. We hypothesized that IGF-IIRα could intensify diabetic heart injury. To demonstrate the potential role of IGF-IIRα in the diabetic heart, we used (SD-TG [IGF-IIRα]) transgenic rat model with cardiac-specific overexpression of IGF-IIRα, along with H9c2 cells, to study the effects of IGF-IIRα in the heart under hyperglycemic conditions. IGF-IIRα was found to remodel calcium homeostasis and intracellular Ca2+ overload-induced autophagy disturbance in the heart during diabetes. IGF-IIRα overexpression induced intracellular Ca2+ alteration by downregulating phosphorylated phospholamban/sarcoplasmic/endoplasmic reticulum calcium-ATPase 2a (PLB/SERCA2a), resulting in the suppression of Ca2+ uptake into the endoplasmic reticulum. Additionally, IGF-IIRα itself contributed to Ca2+ withdrawal from the endoplasmic reticulum by increasing the expression of CaMKIIδ in the active form. Furthermore, alterations in Ca2+ homeostasis significantly dysregulated autophagy in the heart during diabetes. Our study reveals the novel role of IGF-IIRα in regulating cardiac intracellular Ca2+ homeostasis and its related autophagy interference, which contribute to the development of diabetic cardiomyopathy. In future, the present study findings have implications in the development of appropriate therapy to reduce diabetic cardiomyopathy.

Synergic Action of Insulin-like Growth Factor-2 and miRNA-483 in Pterygium Pathogenesis.

Pterygium is a multifactorial disease in which UV-B is speculated to play a key role by inducing oxidative stress and phototoxic DNA damage. In search for candidate molecules that are useful for justifying the intense epithelial proliferation observed in pterygium, our attention has been focused on Insulin-like Growth Factor 2 (IGF-2), mainly detected in embryonic and fetal somatic tissues, which regulate metabolic and mitogenic functions. The binding between IGF-2 and its receptor Insulin-like Growth Factor 1 Receptor (IGF-1R) activates the PI3K-AKT pathway, which leads to the regulation of cell growth, differentiation, and the expression of specific genes. Since IGF2 is regulated by parental imprinting, in different human tumors, the IGF2 Loss of Imprinting (LOI) results in IGF-2- and IGF2-derived intronic miR-483 overexpression. Based on these activities, the purpose of this study was to investigate the overexpression of IGF-2, IGF-1R, and miR-483. Using an immunohistochemical approach, we demonstrated an intense colocalized epithelial overexpression of IGF-2 and IGF-1R in most pterygium samples (Fisher's exact test, p = 0.021). RT-qPCR gene expression analysis confirmed IGF2 upregulation and demonstrated miR-483 expression in pterygium compared to normal conjunctiva (253.2-fold and 12.47-fold, respectively). Therefore, IGF-2/IGF-1R co-expression could suggest their interplay through the two different paracrine/autocrine IGF-2 routes for signaling transfer, which would activate the PI3K/AKT signaling pathway. In this scenario, miR-483 gene family transcription might synergically reinforce IGF-2 oncogenic function through its boosting pro-proliferative and antiapoptotic activity.

IGF2-NR4A2 Signaling Regulates Macrophage Subtypes to Attenuate Liver Cirrhosis.

Liver cirrhosis can lead to liver failure and eventually death. Macrophages are the main contributors to cirrhosis and have a bidirectional role in regulating matrix deposition and degradation. Macrophage-based cell therapy has been developed as an alternative to liver transplantation. However, there is insufficient evidence regarding its safety and efficacy. In this study, we aimed to explore the effect of combining insulin-like growth factor 2 (IGF2) with bone marrow-derived macrophages (BMDMs) to treat mice with liver cirrhosis. We assessed liver inflammation, fibrosis regression, liver function, and liver regeneration in mice with CCl4-induced cirrhosis and treated with BMDM only or IGF2 + BMDM. We performed in vitro experiments in which activated hepatic stellate cells (HSCs) were co-cultured with macrophages in the presence or absence of IGF2. The polarity of macrophages and the degree of inhibition of HSCs were examined. The effect of IGF2 on macrophages was also verified by the overexpression of IGF2. Combining IGF2 with BMDM reduced liver inflammation and fibrosis and increased hepatocyte proliferation. Combining IGF2 with BMDM was more effective than using BMDM alone. In vitro experiments demonstrated that IGF2 inhibited HSCs activation by upregulating NR4A2 to promote the anti-inflammatory macrophages phenotype. IGF2 also increased the synthesis of matrix metalloproteinases (MMPs) by macrophages, which may explain why administering IGF2 combined with BMDM was more effective than administering BMDM only. Our study provides a theoretical basis for the future use of BMDM-based cell therapy to treat liver cirrhosis.

PSUN286 A Rare Case of Non-Islet Cell Tumor Hypoglycemia in Young Female With Metastatic Neuroendocrine Tumor

Abstract Background Non-islet cell tumor hypoglycemia (NICTH) is a rare paraneoplastic syndrome caused by a benign or cancerous tumor that over-secretes various hormones that lead to hypoglycemia. Multiple etiologies were described in literature, the most common of them is abnormal secretion of insulin-like growth factor-2 (IGF-2) known as Doege-Potter syndrome (first described in 1929). Other etiologies include oversecretion of proinsulin, IGF-1, and somatostatin. Estimated incidence of NICTH is one per one million person-years. Tumors of mesenchymal origin are most often described in association with NICTH. Laboratory diagnosis of fasting hypoglycemia associated with serum insulin levels below 3 μU/ml confirm the diagnosis of NICTH. In the case of Doege-Potter syndrome, lab findings show low levels of insulin, c-peptide, IGF-1 and a high IGF-2: IGF-1 ratio, which indicate non-insulin-mediated hypoglycemia due to IGF-2 oversecretion. Neuroendocrine tumors presented with NICTH are rare and only described in several case reports. Clinical Case We report a case of a 34 year old female with metastatic neuroendocrine high grade tumor (WHO grade 3, non small cell, diagnosed 3 years prior to presentation) with metastasis to the bone (status post debulking and radiation) and brain (status post radiation therapy). Patient was admitted due to left ankle cellulitis. Endocrinology was consulted due to incidental finding of hypoglycemia serum glucose of 44 mg/dL. Repeat serum levels showed c-peptide 1 ng/dL (normal 1.1 - 4.4) and glucose of 54 mg/dL. She denied a history of diabetes mellitus, alcohol intake, insulin or sulfonylurea use. She had normal renal and liver function. Continuous infusion of D10 started and after 24 hours the patient's hypoglycemia improved. However, hypoglycemia recurred every morning. Following morning hypoglycemia repeat serum labs showed insulin 1.3 (Normal 2.6-24.9), c-peptide 0.9 ng/dL, and serum glucose of 114 mg/dL confirming that her hypoglycemia was not insulin induced. She was not on any medications known to cause hypoglycemia. CT abdomen without contrast showed left upper quadrant heterogeneous hypoattenuating mass with calcifications, measuring approximately 8.5 cm×10.1 cm×2.6 cm. Conclusion This is a case of a patient with a high grade non small cell metastatic neuroendocrine tumor who presented with NICTH. This is the first case of a neuroendocrine tumor with non-small cell pathology causing NICTH that has been described to-date. Based on the patient's clinical presentation and available laboratory findings with recurrent fasting hypoglycemia, low insulin and c-peptide levels we confirmed diagnosis of NICTH. This patient`s hypoglycemia was most likely induced by IGF-2 overexpression (Doege-Potter syndrome) which is the most common cause of NICTH. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Altered expression of the IGF2‑H19 locus and mitochondrial respiratory complexes in adrenocortical carcinoma.

Abnormalities of the insulin-like growth factor 2 (IGF2)-H19 locus with the overexpression of IGF2 are frequent findings in adrenocortical carcinoma (ACC). The present study assessed the expression of RNAs and microRNAs (miRNAs/miRs) from the IGF2-H19 locus using PCR-based methods in ACC and adrenocortical adenoma (ACA). The results were associated with proteomics data. IGF2 was overexpressed in ACC, and its expression correlated with that of miR-483-3p and miR-483-5p hosted by IGF2. The downregulated expression of H19 in ACC compared to ACA correlated with miR-675 expression hosted by H19. Several proteins exhibited an inverse correlation in expression and were predicted as targets of miR-483-3p, miR-483-5p or miR-675. Subsets of these proteins were differentially expressed between ACC and ACA. These included several proteins involved in mitochondrial metabolism. Among the mitochondrial respiratory complexes, complex I and IV were significantly decreased in ACC compared to ACA. The protein expression of NADH:ubiquinone oxidoreductase subunit C1 (NDUFC1), a subunit of mitochondrial respiratory complex I, was further validated as being lower in ACC compared to ACA and normal adrenals. The silencing of miR-483-5p increased NDUFC1 protein expression and reduced both oxygen consumption and glycolysis rates. On the whole, the findings of the present study reveal the dysregulation of the IGF2-H19 locus and mitochondrial respiration in ACC. These findings may provide a basis for the further understanding of the pathogenesis of ACC and may have potential values for diagnostics and treatment.

Effect of intra-BLA overexpression of IGF-1 on the expression of a contextual fear memory trace.

Growth factors, such as insulin-like growth factor 1 (IGF-1), among others are known for their critical involvement in learning and memory processes. IGF-1 regulates cognitive functions, synapse density, neurotransmission, and adult neurogenesis and induces structural and synaptic plasticity-specific changes. Although IGF-1 has been suggested to participate in different memory processes, its role in memories associated with negative emotional experiences still remains to be elucidated. The principal aim of the present study was to test whether IGF-1 overexpression using adenoviral vectors in basolateral amygdala (BLA) influences both the expression and formation of contextual fear memory, as well as the hippocampal structural plasticity associated with such memory trace. We found that IGF-1 overexpression promotes the formation and expression of a specific contextual fear memory trace, and such effect persisted at least 7 days after recall. Moreover, the overexpression of this growth factor in BLA upregulates the activation of the ERK/MAPK pathway in this brain structure. In addition, intra-BLA IGF-1 overexpression causes dorsal hippocampus (DH) structural plasticity modifications promoting changes in the proportion of mature dendritic spines in the CA1 region, after a weak conditioning protocol. The present findings contribute to the knowledge underlying BLA-DH trace memory of fear and reveal important new insights into the neurobiology and neurochemistry of fear acquisition modulated by IGF-1 overexpression. The understanding of how IGF-1 modulates the formation of a fear contextual trace may pave the way for the development of novel therapeutic strategies focused on fear, anxiety, and trauma-related disorders.

Astrocytic IGF-1 and IGF-1R Orchestrate Mitophagy in Traumatic Brain Injury via Exosomal miR-let-7e.

Defective brain hormonal signaling and autophagy have been associated with neurodegeneration after brain insults, characterized by neuronal loss and cognitive dysfunction. However, few studies have linked them in the context of brain injury. Insulin-like growth factor-1 (IGF-1) is an important hormone that contributes to growth, cell proliferation, and autophagy and is also expressed in the brain. Here, we assessed the clinical data from TBI patients and performed both in vitro and in vivo experiments with proteomic and gene-chip analysis to assess the functions of IGF-1 in mitophagy following TBI. We show that reduced plasma IGF-1 is correlated with cognition in TBI patients. Overexpression of astrocytic IGF-1 improves cognitive dysfunction and mitophagy in TBI mice. Mechanically, proteomics data show that the IGF-1-related NF-κB pathway transcriptionally regulates decapping mRNA2 (Dcp2) and miR-let-7, together with IGF-1R to orchestrate mitophagy in TBI. Finally, we demonstrate that brain injury induces impaired mitophagy at the chronic stage and that IGF-1 treatment could facilitate the mitophagy markers via exosomal miR-let-7e. By showing that IGF-1 is an important mediator of the beneficial effect of the neural-endocrine network in TBI models, our findings place IGF-1/IGF-1R as a potential target capable of noncoding RNAs and opposing mitophagy failure and cognitive impairment in TBI.

Hepatocyte Deletion of IGF2 Prevents DNA Damage and Tumor Formation in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. Serine‐arginine rich splicing factor 3 (SRSF3) plays a critical role in hepatocyte function and its loss in mice promotes chronic liver damage and leads to HCC. Hepatocyte‐specific SRSF3 knockout mice (SKO mice) also overexpress insulin‐like growth factor 2 (IGF2). In the present study, double deletion of Igf2 and Srsf3 (DKO mice) prevents hepatic fibrosis and inflammation, and completely prevents tumor formation, and is associated with decreased proliferation, apoptosis and DNA damage, and restored DNA repair enzyme expression. This is confirmed in vitro, where IGF2 treatment of HepG2 hepatoma cells decreases DNA repair enzyme expression and causes DNA damage. Tumors from the SKO mice also show mutational signatures consistent with homologous recombination and mismatch repair defects. Analysis of frozen human samples shows that SRSF3 protein is decreased sixfold in HCC compared to normal liver tissue but SRSF3 mRNA is increased. Looking at public TCGA data, HCC patients having high SRSF3 mRNA expression show poor survival, as do patients with alterations in known SRSF3‐dependent splicing events. The results indicate that IGF2 overexpression in conjunction with reduced SRSF3 splicing activity could be a major cause of DNA damage and driver of liver cancer.