Overexpression Of IGFBP2 Research Articles

Role of miRNA regulation in IGFBP-2 overexpression and neuronal ferroptosis: Insights into the Nrf2/SLC7A11/GPX4 pathway in Alzheimer's disease.

Alzheimer's disease (AD) is a common neurodegenerative disease with pathological features including amyloid plaque deposits and neurofibrillary tangles. In this study, the expressions of miRNA, IGFBP-2 and neuronal ferritin were detected by qPCR, Western blot and immunohistochemistry. The regulatory effects of miRNA on IGFBP-2 and neuronal ferritin were further verified by intervention experiments with miRNA mimics and inhibitors. Double luciferase reporter gene assay and RNA immunoprecipitation were used to investigate the interaction between miRNA and target genes. Finally, the effect of miRNA on Nrf2/SLC7A11/GPX4 pathway was evaluated by antioxidant enzyme activity and oxidative stress marker detection. The overexpression of IGFBP-2 was found to be significantly increased with the deposition of neuronal ferritin. Expression levels of specific mirnas were significantly down-regulated in AD models and negatively correlated with IGFBP-2 and neuronal ferritin expression. Intervention experiments with miRNA mimics and inhibitors have confirmed that these mirnas can regulate the expression of IGFBP-2 and neuronal ferritin. Further studies revealed that these mirnas affect antioxidant enzyme activity and oxidative stress levels by targeting key genes in the Nrf2/SLC7A11/GPX4 pathway, thereby regulating the deposition of neuronal ferritin.

Developmental 6:2 FTCA exposure impairs renal development in chicken embryos via IGF signaling

6:2 fluorotelomer carboxylic acid (6:2 FTCA) is a perfluorooctanoic acid (PFOA) substitute, which is supposedly less accumulative and toxic than PFOA. However, 6:2 FTCA is structurally similar to PFOA, and there had already been reports about its toxicities comparable to PFOA. The aim of the current study is to assess potential effects of developmental exposure to 6:2 FTCA on the development of kidney in chicken embryo and to investigate underlying mechanism. Fertile chicken eggs were exposed to 1.25 mg/kg, 2.5 mg/kg or 5 mg/kg doses of 6:2 FTCA, or 2 mg/kg PFOA, then incubated to hatch. Serum and kidney of hatchling chickens were collected. Blood urea nitrogen (BUN) and creatinine (Cre) levels were measured with commercially available kits. Morphology of kidney was assessed with histopathology. To further reveal molecular mechanism of observed endpoints, IGF signaling molecules were assessed in the kidney samples with qRT-PCR, results indicated that IGFBP3 is a potentially crucial molecule. Lentiviruses overexpressing or silencing IGFBP3 were designed and applied to enhance/suppress the expression of IGFBP3 in developing chicken embryo for further verification of its role in the observed effects. Disrupted nephron formation, in the manifestation of decreased glomeruli number/area and increased serum BUN/Cre levels, was observed in the animals developmentally exposed to 6:2 FTCA. Correspondingly, IGF signaling molecules (IGF1, IGF1R and IGFBP3) were affected by 6:2 FTCA exposure. Meanwhile, overexpression of IGFBP3 effectively alleviated such changes, while silencing of IGFBP3 mimicked observed effects. In conclusion, developmental exposure to 6:2 FTCA is associated with disrupted chicken embryo renal development, in which IGFBP3 seems to be a remarkable contributor, suggesting potential health risks for human and other species. Further risk assessments and mechanistic works are necessary.

LncRNA Snhg12/IGFBP3 axis is involved in liver fibrosis by promoting the proliferation and activation of mouse hepatic stellate cells.

Liver fibrosis is a persistent damage repair response triggered by various injury factors, which leads to an abnormal accumulation of extracellular matrix within liver tissue samples. The current clinical treatment of liver fibrosis is currently ineffective; therefore, elucidating the mechanism of liver fibrogenesis is of significant importance. Herein, the function and related mechanisms of lncRNA Snhg12 within hepatic fibrosis were investigated. Snhg12 expression was shown to be increased in mouse hepatic fibrotic tissue samples, and Snhg12 knockdown suppressed hepatic pathological injury and down-regulated the expression levels of fibrosis-associated proteins. Mechanistically, Snhg12 played a role in the early activation of mouse hepatic stellate cells (mHSCs) based on bioinformatics analysis, and Snhg12 was positively correlated with Igfbp3 expression. Further experimental results demonstrated that Snhg12 knockdown impeded mHSCs proliferation and activation and also downregulated the protein expression of Igfbp3. Snhg12 could interact with IGFBP3 and boost its protein stability, and overexpression of Igfbp3 partially reversed the inhibition of mHSCsproliferation and activation by the knockdown of Snhg12. In conclusion, LncRNA Snhg12 mediates liver fibrosis by targeting IGFBP3 and promoting its protein stability, thereby promoting mHSC proliferation and activation. Snhg12 has been identified as an underlying target for treating liver fibrosis.

Gastric Cancer Immune Subtypes and Prognostic Modeling: Insights from Aging-Related Gene Analysis.

Gastric cancer (GC) is highly heterogeneous and influenced by aging-related factors. This study aimed to improve individualized prognostic assessment of GC by identifying aging-related genes and subtypes. Immune scores of GC samples from GEO and TCGA databases were calculated using ESTIMATE and scored as high immune (IS_high) and low immune (IS_low). ssGSEA was used to analyze immune cell infiltration. Univariate Cox regression was employed to identify prognosis-related genes. LASSO regression analysis was used to construct a prognostic model. GSVA enrichment analysis was applied to determine pathways. CCK-8, wound healing, and Transwell assays tested the proliferation, migration, and invasion of the GC cell line (AGS). Cell cycle and aging were examined using flow cytometry, β-galactosidase staining, and Western blotting. Two aging-related GC subtypes were identified. Subtype 2 was characterized as lower survival probability and higher risk, along with a more immune-responsive tumor microenvironment. Three genes (IGFBP5, BCL11B, and AKR1B1) screened from aging-related genes were used to establish a prognosis model. The AUC values of the model were greater than 0.669, exhibiting strong prognostic value. In vitro, IGFBP5 overexpression in AGS cells was found to decrease viability, migration, and invasion, alter the cell cycle, and increase aging biomarkers (SA-β-galactosidase, p53, and p21). This analysis uncovered the immune characteristics of two subtypes and aging-related prognosis genes in GC. The prognostic model established for three aging-related genes (IGFBP5, BCL11B, and AKR1B1) demonstrated good prognosis performance, providing a foundation for personalized treatment strategies aimed at GC.

The chromatin remodeling protein BRG1 regulates HSC-myofibroblast differentiation and liver fibrosis

Excessive fibrogenic response in the liver disrupts normal hepatic anatomy and function heralding such end-stage liver diseases as hepatocellular carcinoma and cirrhosis. Myofibroblasts, derived primarily from hepatic stellate cells (HSCs), are the effector of liver fibrosis. In the present study we investigated the mechanism by which Brahma-related gene 1 (BRG1, encoded by Smarca4) regulates HSC-myofibroblast transition and the implication in intervention against liver fibrosis. We report that BRG1 expression was elevated during HSC maturation in cell culture, in animal models, and in human cirrhotic liver biopsy specimens. HSC-specific deletion of BRG1 attenuated liver fibrosis in several different animal models. In addition, BRG1 ablation in myofibroblasts ameliorated liver fibrosis. RNA-seq identified IGFBP5 as a novel target for BRG1. Over-expression of IGFBP5 partially rescued the deficiency in myofibroblast activation when BRG1 was depleted. On the contrary, IGFBP5 knockdown suppressed HSC-myofibroblast transition in vitro and mollified liver fibrosis in mice. Mechanistically, IGFBP5 interacted with Bat3 to stabilize the Bat3-TβR complex and sustain TGF-β signaling. In conclusion, our data provide compelling evidence that BRG1 is a pivotal regulator of liver fibrosis by programming HSC-myofibroblast transition.

Deciphering the Divergent Gene Expression Landscapes of m6A/m5C/m1A Methylation Regulators in Hepatocellular Carcinoma Through Single-Cell and Bulk RNA Transcriptomic Analysis.

RNA modifications mediated by the m6A, m1A, and m5C regulatory genes are crucial for the progression of malignancy. This study aimed to explore the expression of regulator genes for m6A/m5C/m1A methylation at the single-cell level and to validate their expression in cancerous and adjacent para-cancerous liver tissues of adult patients with HCC who underwent tumor resection. The bulk sequencing from The Cancer Genome Atlas (TCGA) database and the single-cell RNA sequencing (scRNA-seq) data obtained from the Gene Expression Omnibus (GEO) database were used to identify the dysregulated m6A/m5C/m1A genes for hepatocellular carcinoma (HCC). A real-time polymerase chain reaction (real-time PCR) was used to measure the expression of dysregulated m6A/m5C/m1A genes in collected human HCC tissues and compared with adjacent para-cancerous liver tissues. Immune cell infiltration with these significantly expressed methylation-related genes was evaluated using Timer2.0. A discrepancy in m6A/m5C/m1A gene expression was observed between bulk sequencing and scRNA-seq. The clustered heatmap of the scRNA-seq-identified dysregulated m6A/m5C/m1A genes in TCGA cohort revealed heterogeneous expression of these methylation regulators within the cancer, whereas their expression in the adjacent liver tissues was more homogeneous. The real-time PCR validated the significant overexpression of DNMT1, NSUN5, TRMT6, IGF2BP1, and IGFBP3, which were identified using scRNA-seq, and IGFBP2, which was identified using bulk sequencing. These dysregulated methylation genes are mainly correlated with the infiltration of natural killer cells. This study suggests that cellular diversity inside tumors contributes to the discrepancy in the expression of methylation regulator genes between traditional bulk sequencing and scRNA-seq. This study identified five regulatory genes that will be the focus of further studies regarding the function of m6A/m5C/m1A in HCC.

Extracellular matrix stiffness aggravates urethral stricture through Igfbp3/Smad pathway

Urethral stricture refers to the narrowing of the urethral lumen. While previous studies have hinted at inflammation as the initial driver of this condition, the reasons and mechanisms behind its progression remain largely unknown. By Atomic force microscope (AFM), researchers measured the matrix stiffness of urethra to be 5.23 ± 0.37 kPa for normal tissue and 41.59 ± 2.48 kPa for stricture urethral scar. Similar results were observed in rat urethral stricture models, where the matrix stiffness of normal urethra was 4.29 ± 0.82 kPa, while 32.94 ± 7.12 kPa for urethral stricture scar. Notably, the matrix stiffness increased in rat models over time. To further investigate, polyacrylamide hydrogels were employed to mimic different levels of stiffness for normal and stricture condition. Interestingly, higher matrix stiffness led to an increased fibroblast-to-myofibroblast transition (FMT) in rat urethral fibroblasts, indicated by enhanced expression of α-SMA and Collagen I, as well as changing in the morphology of fibroblast. RNA-seq analysis suggested that Igfbp3/Smads might regulate the progressive FMT in urethral stricture. In the experiment where the expression of Igfbp3 was inhibited, increasing matrix stiffness lose the potential to stimulate FMT progression and the expression of p-Smad2/3 decreased. On the contrary, overexpression of Igfbp3 promoted the process of FMT in urethral fibroblasts. In conclusion, Igfbp3/Smad pathway appeared to be involved in the progression of urethral fibrosis. This finding suggested that Igfbp3/Smad might be an promising target for future research and treatment in this filed.

Abstract P1150: Integrative Transcriptomics And Cell Systems Analyses Reveal Protective Pathways Controlled By Igfbp-3 In Anthracycline-induced Cardiotoxicity

Rationale: Anthracyclines such as doxorubicin (Dox) are effective chemotherapeutic agents. Their use however is hindered by the risk of anthracycline-induced cardiotoxicity (AIC). Our understanding of protective pathways activated by cardiomyocytes following AIC remains incomplete. Insulin-like growth factor binding protein (Igfbp)-3, the most abundant Igfbp family member in the circulation, is associated with effects on the metabolism, proliferation, and survival of various cell types. Whereas Igfbp-3 is significantly induced by Dox in the heart, its role in AIC remains ill-defined. Methods and Results: We investigated molecular mechanisms as well as systems-level transcriptomic consequences of manipulating Igfbp-3 in AIC using neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Our findings reveal that Dox induces the nuclear enrichment of Igfbp-3 in cardiomyocytes. Furthermore, Igfbp-3 overexpression leads to a significant reduction of γ-H2AX, a marker of DNA damage (56% reduction vs. control, n=3, P<0.05), and impedes topoisomerase (Top)-2β expression which forms a Top2β-Dox-DNA cleavage complex leading to DNA double-strand breaks (44% reduction vs. control, n=3, P<0.01). Next generation sequencing and gene network analyses of iPSC-CMs treated with Dox reveal that Igfbp-3 perturbation modulates genes implicated in microtubule function and cardiomyocyte contraction. Stimulated Emission Depletion (STED) microscopy and immunoblotting further indicate that Igfbp-3 knockdown exacerbates detyrosinated microtubule accumulation (STED, 21% increase vs. control, n=16-19, P<0.05; immunoblotting, 62% increase vs. control, n=6, P<0.01) – a hallmark of increased cardiomyocyte stiffness and heart failure – and favorably affects contractility following Dox treatment. Conclusion: Our delineation of the protective role of Igfbp-3 in AIC provides novel insight into pathways induced by cardiomyocytes to mitigate DNA damage and apoptosis, and improve contractile function.

Abstract B076: IGFBP3 promotes resistance to olaparib via modulating EGFR signaling in advanced prostate cancer

Abstract Background: Castration-resistant prostate cancer (CRPC) is an incurable disease and a leading cause of cancer death in men worldwide. Olaparib (Lynparza) was among the first PARP inhibitors (PARPi) approved for the treatment of CRPC tumors harboring DNA repair defects. However, clinical resistance to PARPi’s has been documented. The mechanisms underlying resistance to PARPi’s remain elusive. To study acquired resistance, we developed olaparib-resistant LN-OlapR and 2B-OlapR cell lines generated through chronic olaparib treatment of the olaparib-sensitive cell lines LNCaP and C4-2B, respectively. RNA-seq revealed IGFBP3 is overexpressed in both OlapR cell lines. IGFBP3 overexpression is correlated with poor clinical outcome and is thought to participate in DNA repair pathways. IGFBP3 plays a key role in nonhomologous end joining (NHEJ) repair through a ternary complex with EGFR and DNA-PKcs. The IGFBP3/EGFR signaling axis is thought to modulate NHEJ repair and could have implications for PARPi sensitivity. We hypothesize that increased IGFBP3 expression promotes PARPi resistance by enhancing DNA repair capacity. Methods: RNA-sequencing and gene set enrichment analysis were used to determine the expression profile changes in resistant cells compared to parental cells. Real time PCR and western blots confirmed the expression of DNA damage repair genes such as γH2AX, EGFR, and DNA-PKcs. ELISA was used to determine IGFBP3 secretion. RNAi was used to inhibit IGFBP3 and EGFR expression. Gefitinib was used to inhibit EGFR activity. Cell viability assays were used to assess cell growth. Results: Transcriptomic profiling revealed that IGFBP3 is highly expressed in resistant models. We verified increased levels of IGFBP3 RNA and protein in both OlapR models. We found that RNAi inhibition of IGFBP3 increases γH2AX and cleaved-PARP protein levels in the resistant models, which suggests accumulation of DNA double strand breaks (DSBs) leading to genomic instability and cell death. We discovered increased phosphorylation of EGFR and DNA-PKcs in the resistant cells. Furthermore, silencing/inhibiting IGFBP3 and EGFR reduces OlapR cell viability and resensitizes resistant cells to treatment. Conclusions: Our findings demonstrated that inhibiting IGFBP3 and EGFR aids in PARPi sensitivity in the resistant setting. Future work will utilize OlapR models to study how the IGFBP3/EGFR/DNA-PKcs protein complex promotes the development of resistance. Understanding the role of IGFBP3 in PARPi resistance will enhance our ability to re-sensitize resistant CRPC to PARPi therapeutics. Citation Format: Amy R. Leslie, Allen C. Gao, Alan P. Lombard, Shu Ning. IGFBP3 promotes resistance to olaparib via modulating EGFR signaling in advanced prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B076.

Abstract 3862: IGFBP3 promotes resistance to olaparib via modulating EGFR signaling in advanced prostate cancer

Abstract Background: Castration-resistant prostate cancer (CRPC) is an incurable disease and a leading cause of cancer death in men worldwide. Olaparib (Lynparza) was among the first PARP inhibitors (PARPi) approved for the treatment of CRPC tumors harboring DNA repair defects. However, clinical resistance to PARPi’s has been documented. The mechanisms underlying resistance to PARPi’s remain elusive. To study acquired resistance, we developed olaparib-resistant LN-OlapR and 2B-OlapR cell lines generated through chronic olaparib treatment of the olaparib-sensitive cell lines LNCaP and C4-2B, respectively. RNA-seq revealed IGFBP3 is overexpressed in both OlapR cell lines. IGFBP3 overexpression is correlated with poor clinical outcome and is thought to participate in DNA repair pathways. IGFBP3 plays a key role in nonhomologous end joining (NHEJ) repair through a ternary complex with EGFR and DNA-PKcs. The IGFBP3/EGFR signaling axis is thought to modulate NHEJ repair and could have implications for PARPi sensitivity. We hypothesize that increased IGFBP3 expression promotes PARPi resistance by enhancing DNA repair capacity. Methods: RNA-sequencing and gene set enrichment analysis were used to determine the expression profile changes in resistant cells compared to parental cells. Real time PCR and western blots confirmed the expression of DNA damage repair genes such as γH2AX, EGFR, and DNA-PKcs. ELISA was used to determine IGFBP3 secretion. RNAi was used to inhibit IGFBP3 and EGFR expression. Gefitinib was used to inhibit EGFR activity. Cell viability assays were used to assess cell growth. Results: Transcriptomic profiling revealed that IGFBP3 is highly expressed in resistant models. We verified increased levels of IGFBP3 RNA and protein in both OlapR models. We found that RNAi inhibition of IGFBP3 increases γH2AX and cleaved-PARP protein levels in the resistant models, which suggests accumulation of DNA double strand breaks (DSBs) leading to genomic instability and cell death. We discovered increased phosphorylation of EGFR and DNA-PKcs in the resistant cells. Furthermore, silencing/inhibiting IGFBP3 and EGFR reduces OlapR cell viability and resensitizes resistant cells to treatment. Conclusions: Our findings demonstrated that inhibiting IGFBP3 and EGFR aids in PARPi sensitivity in the resistant setting. Future work will utilize OlapR models to study how the IGFBP3/EGFR/DNA-PKcs protein complex promotes the development of resistance. Understanding the role of IGFBP3 in PARPi resistance will enhance our ability to re-sensitize resistant CRPC to PARPi therapeutics. Citation Format: Amy R. Leslie, Shu Ning, Leandro S. D'Abronzo, Cameron Armstrong, Masuda Sharifi, Zachary A. Schaaf, Wei Lou, Christopher P. Evans, Hong-Wu Chen, Alan Lombard, Allen C. Gao. IGFBP3 promotes resistance to olaparib via modulating EGFR signaling in advanced prostate cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3862.

MiR-19a-3p Promotes Aerobic Glycolysis in Ovarian Cancer Cells via IGFBP3/PI3K/AKT Pathway.

Aerobic glycolysis is a prominent feature of cancer. Here, we reported that miR-19a-3p promotes aerobic glycolysis in ovarian cancer cells SKVO3 and ES-2 by increased production of ATP, lactic acid, extracellular acidification (ECAR), and increased expression of PKM2, LDHA, GLUT1 and GLUT3. Further study showed that over-expression of IGFBP3, the target of miR-19a-3p, decreases aerobic glycolysis in ovarian cancer cells, while knockdown of IGFBP3 expression increases aerobic glycolysis. The rescue assay suggested that miR-19a-3p promotes aerobic glycolysis in ovarian cancer cells through targeting IGFBP3. Moreover, over-expression of miR-19a-3p or silencing of IGFBP3 expression promoted activation of AKT, which is important for aerobic glycolysis in cancer cells, indicating that miR-19a-3p promotes aerobic glycolysis in ovarian cancer cells through the IGFBP3/PI3K/AKT pathway. This suggests that miR-19a-3p and IGFBP3 may serve as potential treatment targets of ovarian cancer.

Identification and verification of IGFBP3 and YTHDC1 as biomarkers associated with immune infiltration and mitophagy in hypertrophic cardiomyopathy.

Background: Hypertrophic cardiomyopathy (HCM) is the main cause of sudden cardiac death among young adults, yet its pathogenesis remains vague. N6-methyladenosine (m6A) methylation modification was involved in various cardiovascular diseases such as coronary heart disease and heart failure, although its influence on HCM remains unclear. This study aimed to explore the potential role of m6A in the diagnosis and pathogenesis of HCM. Methods: GSE36961 including 106 HCM and 39 controls was used in the study. The HCM-related m6A regulators were selected using support vector machine recursive feature elimination and random forest algorithm. A significant gene signature was then established using least absolute shrinkage and selection operator and then verified by GSE130036. Subgroup classification of HCM was performed based on the expression of m6A biomarkers. Gene set variation analysis was employed to explore the functional difference between distinct subgroups. Weighted gene co-expression network analysis was used to determine the m6A-related hub module. Single-sample gene set enrichment analysis was conducted to assess the immune and mitophagy features between subgroups. Besides, transfection of recombinant plasmids with targeted genes into H9c2 cells was performed to further verify the function of the significant biomarkers. Results: Significant difference existed in m6A landscape between HCM and control patients, among which IGFBP3 and YTHDC1 were identified as the independent biomarkers of HCM. Highly infiltrated immune cells (MDSC, macrophages, etc.), more enriched immune-related pathways (TNFα signaling via NFκB and IL6-JAK-STAT3 signaling) and cardiac remodeling-associated pathways (epithelial mesenchymal transition, angiogenesis, etc.) were identified in the subgroup with higher IGFBP3. Consistently, overexpression of IGFBP3 in H9c2 cells led to upregulation of extracellular-matrix-related genes (COL1A2, COL3A1 and MMP9) and inflammation-related genes (TNFα and IL6). Besides, higher YTHDC1 expression seemed to be consistent with less-activated mitophagy (PINK1-PRKN mediated mitophagy) and energy metabolism. Further experiments demonstrated that overexpression of YTHDC1 resulted in up-regulation of PINK and PRKN in cardiomyocytes, which are essential genes mediating mitophagy. Conclusion: Two m6A readers (IGFBP3 and YTHDC1) well distinguished HCM and may facilitate clinical diagnosis. IGFBP3 may play a role in the immune-microenvironments and remodeling of cardiac tissues, while YTHDC1 may influence mitophagy and energy metabolism in HCM.

Insulin-like growth factor 5 associates with human Aß plaques and promotes cognitive impairment.

Risk factors such as dysregulation of Insulin-like growth factor (IGF) signaling have been linked to Alzheimer’s disease. Here we show that Insulin-like Growth Factor Binding Protein 5 (Igfbp5), an inhibitory binding protein for insulin-like growth factor 1 (Igf-1) accumulates in hippocampal pyramidal neurons and in amyloid plaques in brains of Alzheimer patients. We investigated the pathogenic relevance of this finding with transgenic mice overexpressing Igfbp5 in pyramidal neurons of the brain. Neuronal overexpression of Igfbp5 prevents the training-induced increase of hippocampal and cortical Bdnf expression and reduces the effects of exercise on memory retention, but not on learning acquisition. Hence, elevated IGFBP5 expression could be responsible for some of the early cognitive deficits that occur during the course of Alzheimer’s disease.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40478-022-01352-5.

MiR-22-3p Inhibits Proliferation and Promotes Differentiation of Skeletal Muscle Cells by Targeting IGFBP3 in Hu Sheep.

Simple SummaryThe meat production of Hu sheep affects the mutton supply, and how to increase the meat production is the primary focus of genetic breeding. Therefore, in order to explore the key factors affecting the proliferation and differentiation of Hu sheep skeletal muscle cells, we performed functional verification of miRNA at the cellular level. Our findings are helpful to clarify the molecular regulation mechanism of proliferation and differentiation of skeletal muscle cells, which will benefit the molecular breeding of Hu sheep.The growth and development of skeletal muscle require a series of regulatory factors. MiRNA is a non-coding RNA with a length of about 22 nt, which can inhibit the expression of mRNA and plays an important role in the growth and development of muscle cells. The role of miR-22-3p in C2C12 cells and porcine skeletal muscle has been reported, but it has not been verified in Hu sheep skeletal muscle. Through qPCR, CCK-8, EdU and cell cycle studies, we found that overexpression of miR-22-3p inhibited proliferation of skeletal muscle cells (p < 0.01). The results of qPCR and immunofluorescence showed that overexpression of miR-22-3p promoted differentiation of skeletal muscle cells (p < 0.01), while the results of inhibiting the expression of miR-22-3p were the opposite. These results suggested that miR-22-3p functions in growth and development of sheep skeletal muscle cells. Bioinformatic analysis with mirDIP, miRTargets, and RNAhybrid software suggested IGFBP3 was the target of miR-22-3p, which was confirmed by dual-luciferase reporter system assay. IGFBP3 is highly expressed in sheep skeletal muscle cells. Overexpression of IGFBP3 was found to promote proliferation of skeletal muscle cells indicated by qPCR, CCK-8, EdU, and cell cycle studies (p < 0.01). The results of qPCR and immunofluorescence experiments proved that overexpression of IGFBP3 inhibited differentiation of skeletal muscle cells (p < 0.01), while the results of interfering IGFBP3 with siRNA were the opposite. These results indicate that miR-22-3p is involved in proliferation and differentiation of skeletal muscle cells by targeting IGFBP3.

PAPPA2 Promote the Proliferation of Dermal Papilla Cells in Hu Sheep (Ovis aries) by Regulating IGFBP5.

Hu sheep (Ovis aries) is a rare white sheep breed, with four different types of lambskin patterns that have different values. However, the genetic mechanisms underlying different types of pattern formation remains unclear. This research aimed to characterize the molecular mechanism of differentially expressed gene PAPPA2 affecting the pattern type of Hu sheep’s lambskin at the cellular level. Thus, RT-qPCR, EdU and Cell Cycle detection were used to explore the effect of PAPPA2 and IGFBP5 (a protein that can be hydrolyzed by PAPPA2) on the proliferation of dermal papilla cells (DPCs) after overexpression or interference with PAPPA2 and IGFBP5. The expression level of PAPPA2 in straight DPCs was 4.79 ± 1.84 times higher than curved. Overexpression of PAPPA2 promoted the proliferation of DPCs and also increased the expression of IGFBP5. Conversely, overexpression of IGFBP5 reduced the proliferation of DPCs. However, the proliferation of DPCs was restored by co-overexpression of PAPPA2 and IGFBP5 compared with overexpression of IGFBP5 alone. Thus, PAPPA2 can affect the proliferation of DPCs through regulating IGFBP5 and then participate in lambskin pattern determination. Overall, we preliminarily clarified the critical role played by PAPPA2 during the formation of different pattern in Hu sheep lambskin.

HMGA2 contributes to vascular development and sprouting angiogenesis by promoting IGFBP2 production

Angiogenesis is the process by which new blood vessels form from preexisting vessels and regulates the processes of embryonic development, wound healing and tumorigenesis. HMGA2 is involved in the occurrence of several cancers, but its biological role and the exact downstream genes involved in vascular development and sprouting angiogenesis remain largely unknown. Here, we first found that HMGA2 knockdown in zebrafish embryos resulted in defects of central artery formation. RNA sequencing revealed that IGFBP2 was significantly downregulated by interference with HMGA2, and IGFBP2 overexpression reversed the inhibition of brain vascular development caused by HMGA2 deficiency. In vitro, we further found that HMGA2 knockdown blocked the migration, tube formation and branching of HUVECs. Similarly, IGFBP2 protein overexpression attenuated the impairments induced by HMGA2 deficiency. Moreover, the promotion of angiogenesis by HMGA2 overexpression was verified in a Matrigel plug assay. We next found that HMGA2 bound directly to a region in the IGFBP2 promoter and positively regulated IGFBP2 expression. Interestingly, the mRNA expression levels of HMGA2 and IGFBP2 were increased significantly in the peripheral blood of hemangioma patients, indicating that overexpression of HMGA2 and IGFBP2 results in vessel formation, consistent with the results of the in vivo and in vitro experiments. In summary, our findings demonstrate that HMGA2 promotes central artery formation by modulating angiogenesis via IGFBP2 induction.

IGFBP-2 as a biomarker in NAFLD improves hepatic steatosis: an integrated bioinformatics and experimental study

Background and aimsNon-alcoholic fatty liver disease (NAFLD) has become a common chronic liver disease in the world. Simple steatosis (SS) is the early phase of NAFLD. However, the molecular mechanisms underlying the development of steatosis have not yet been fully elucidated.MethodsTwo public datasets (GSE48452 and GSE89632) through the Gene Expression Omnibus (GEO) database were used to identify differentially expressed genes (DEGs) in the development of steatosis. A total of 72 participants including 38 normal histological controls and 34 SS patients were included in this study. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) network analysis were performed to explore the function of DEGs. The results were further confirmed in high-fat diet (HFD)-fed mice and oleate-treated HepG2 cells.ResultsTotal 57 DEGs including 31 up- and 26 down-regulated genes between SS patients and healthy controls were determined. GO and KEGG analysis showed that most of the DEGs were enriched in the ligand–receptor signaling pathways. PPI network construction was used to identify the hub genes of the DEGs. MYC, ANXA2, GDF15, AGTR1, NAMPT, LEPR, IGFBP-2, IL1RN, MMP7, and APLNR were identified as hub genes, and IGFBP-2 expression was found to be reversely associated with hepatic steatosis, fasting insulin, HOMA-IR index, and ALT levels. In HFD-fed mice, hepatic IGFBP-2 was also downregulated and negatively associated with hepatic triglyceride (TG) levels. Moreover, overexpression of IGFBP-2 ameliorated the oleate induced accumulation of TGs in hepatocytes.ConclusionsThis study identified novel gene signatures in the hepatic steatosis and will provide new understanding and molecular clues of hepatic steatosis.

IGFBP2 in cancer: Pathological role and clinical significance (Review).

The versatility of IGFBP2, as a secreted protein in cancer cells or a cytoplasmic signaling effector, has been extensively investigated in many malignant cancers. Over the last few decades, IGFBP2, a key member of the IGFBP family, has been identified as an important oncogene in multiple human cancers. In addition, a growing number of studies have shown that IGFBP2 is greatly elevated in serum or tissue in patients with malignant tumors and plays an essential role in several key oncogenic processes, such as tumor cellular proliferation, migration, invasion, angiogenesis, epithelial‑to‑mesenchymal transition, and immunoregulation, which are involved in a variety of signal pathways, usually via an IGF‑independent means. Moreover, growing evidence indicates that aberrant overexpression of IGFBP2 may serve as a useful biomarker for the diagnosis and prognosis of patients, as well as act as a potential therapeutic target for the management of clinical treatment in patients with malignant disease. In the present review, we summarize the current points of view that IGFBP2 performs a role in the initiation and progression of various types of cancer by interacting with several key molecules involved in cancer signaling pathways. We also discuss its potential clinical application value as a diagnostic/prognostic biomarker for patients with malignant tumors.

Regulation of β-catenin by IGFBP2 and its cytoplasmic actions in glioma

IGFBP2 is one of the highly expressed genes in glioblastoma (GBM). It has both IGF dependent and independent activities. IGF independent actions are mediated by the activation of integrin signalling through its RGD motif present at C-terminal domain. One of the actions of IGFBP2 is to regulate β-catenin by the inactivation of GSK3β, which preferentially accumulates in the cytoplasm. The mechanism of nuclear β-catenin regulation by IGFBP2 and role of cytoplasmic β-catenin is not clear. We aimed to understand the mechanism in GBM cell lines. The gene expression studies were performed by RT-PCR, western blot analysis; the knockdown of genes was performed by shRNA transfection; RNAIP and luciferase reporter assays were utilized to study the cytoplasmic regulation of genes by β-catenin; neurosphere assays were performed to study the stemness of cells. IGFBP2 overexpression or treatment in GBM cells regulates β-catenin, TRIM33 (E3 ubiquitin ligase) and Oct4 genes. TRIM33 was induced by IGFBP2. β-catenin was found to accumulate predominantly in the cytoplasm and nuclear β-catenin was depleted by IGFBP2 induced TRIM33. IGFBP2 regulated cytoplasmic β-catenin binds to 3' UTR of Oct4 RNA. IGFBP2 was also able to induce stemness of glioma cells. IGFBP2 induces TRIM33 which regulates the nuclear β-catenin protein. In addition, IGFBP2 stabilizes the cytoplasmic β-catenin which is involved in the regulation of Oct4 transcript and consequently induction of stemness of glioma cells.

Multivariate analysis reveals differentially expressed genes among distinct subtypes of diffuse astrocytic gliomas: diagnostic implications

Diagnosis and classification of gliomas mostly relies on histopathology and a few genetic markers. Here we interrogated microarray gene expression profiles (GEP) of 268 diffuse astrocytic gliomas—33 diffuse astrocytomas (DA), 52 anaplastic astrocytomas (AA) and 183 primary glioblastoma (GBM)—based on multivariate analysis, to identify discriminatory GEP that might support precise histopathological tumor stratification, particularly among inconclusive cases with II–III grade diagnosed, which have different prognosis and treatment strategies. Microarrays based GEP was analyzed on 155 diffuse astrocytic gliomas (discovery cohort) and validated in another 113 tumors (validation set) via sequential univariate analysis (pairwise comparison) for discriminatory gene selection, followed by nonnegative matrix factorization and canonical biplot for identification of discriminatory GEP among the distinct histological tumor subtypes. GEP data analysis identified a set of 27 genes capable of differentiating among distinct subtypes of gliomas that might support current histological classification. DA + AA showed similar molecular profiles with only a few discriminatory genes overexpressed (FSTL5 and SFRP2) and underexpressed (XIST, TOP2A and SHOX2) in DA vs AA and GBM. Compared to DA + AA, GBM displayed underexpression of ETNPPL, SH3GL2, GABRG2, SPX, DPP10, GABRB2 and CNTN3 and overexpression of CHI3L1, IGFBP3, COL1A1 and VEGFA, among other differentially expressed genes.