Turbulence Activates Platelet Biogenesis to Enable Clinical Scale Ex Vivo Production.

The ex vivo generation of platelets from human-induced pluripotent cells (hiPSCs) is expected to compensate donor-dependent transfusion systems. However, manufacturing the clinically required number of platelets remains unachieved due to the low platelet release from hiPSC-derived megakaryocytes (hiPSC-MKs). Here, we report turbulence as a physical regulator in thrombopoiesis in vivo and its application to turbulence-controllable bioreactors. The identification of turbulent energy as a determinant parameter allowed scale-up to 8 L for the generation of 100 billion-order platelets from hiPSC-MKs, which satisfies clinical requirements. Turbulent flow promoted the release from megakaryocytes of IGFBP2, MIF, and Nardilysin to facilitate platelet shedding. hiPSC-platelets showed properties of bona fide human platelets, including circulation and hemostasis capacities upon transfusion in two animal models. This study provides a concept in which a coordinated physico-chemical mechanism promotes platelet biogenesis and an innovative strategy for ex vivo platelet manufacturing.

IGFBP2 induces podocyte apoptosis promoted by mitochondrial damage via integrin α5/FAK in diabetic kidney disease.

Podocyte apoptosis or loss is the pivotal pathological characteristic of diabetic kidney disease (DKD). Insulin-like growth factor-binding protein 2 (IGFBP2) have a proinflammatory and proapoptotic effect on diseases. Previous studies have shown that serum IGFBP2 level significantly increased in DKD patients, but the precise mechanisms remain unclear. Here, we found that IGFBP2 levels obviously increased under a diabetic state and high glucose stimuli. Deficiency of IGFBP2 attenuated the urine protein, renal pathological injury and glomeruli hypertrophy of DKD mice induced by STZ, and knockdown or deletion of IGFBP2 alleviated podocytes apoptosis induced by high concentration of glucose or in DKD mouse. Furthermore, IGFBP2 facilitated apoptosis, which was characterized by increase in inflammation and oxidative stress, by binding with integrin α5 (ITGA5) of podocytes, and then activating the phosphorylation of focal adhesion kinase (FAK)-mediated mitochondrial injury, including membrane potential decreasing, ROS production increasing. Moreover, ITGA5 knockdown or FAK inhibition attenuated the podocyte apoptosis caused by high glucose or IGFBP2 overexpression. Taken together, these findings unveiled the insight mechanism that IGFBP2 increased podocyte apoptosis by mitochondrial injury via ITGA5/FAK phosphorylation pathway in DKD progression, and provided the potential therapeutic strategies for diabetic kidney disease.

FGF1 ameliorates obesity-associated hepatic steatosis by reversing IGFBP2 hypermethylation.

Obesity is a major contributing factor for metabolic-associated fatty liver disease (MAFLD). Fibroblast growth factor (FGF) 1 is the first paracrine FGF family member identified to exhibit promising metabolic regulatory properties capable of conferring glucose-lowering and insulin-sensitizing effect. This study explores the role and molecular underpinnings of FGF1 in obesity-associated hepatic steatosis. In a mouse high-fat diet (HFD)-induced MAFLD model, chronic treatment with recombinant FGF1(rFGF1) was found to effectively reduce the severity of insulin resistance, hyperlipidemia, and inflammation. FGF1 treatment decreased lipid accumulation in the mouse liver and palmitic acid-treated AML12 cells. These effects were associated with decreased mature form SREBF1 expression and its target genes FASN and SCD1. Interestingly, we uncovered that rFGF1 significantly induced IGFBP2 expression at both mRNA and protein levels in HFD-fed mouse livers and cultured hepatocytes treated with palmitic acid. Adeno-associated virus-mediated IGFBP2 suppression significantly diminished the therapeutic benefit of rFGF1 on MAFLD-associated phenotypes, indicating that IGFBP2 plays a crucial role in the FGF1-mediated reduction of hepatic steatosis. Further analysis revealed that rFGF1 treatment reduces the recruitment of DNA methyltransferase 3 alpha to the IGFBP2 genomic locus, leading to decreased IGFBP2 gene methylation and increased mRNA and protein expression. Collectively, our findings reveal FGF1 modulation of lipid metabolism via epigenetic regulation of IGFBP2 expression, and unravel the therapeutic potential of the FGF1-IGFBP2 axis in metabolic diseases associated with obesity.

Targeted proteomics identifies potential biomarkers of dysglycaemia, beta cell function and insulin sensitivity in Black African men and women.

AIMS/HYPOTHESIS: Using a targeted proteomics approach, we aimed to identify and validate circulating proteins associated with impaired glucose metabolism (IGM) and type 2 diabetes in a Black South African cohort. In addition, we assessed sex-specific associations between the validated proteins and pathophysiological pathways of type 2 diabetes. METHODS: This cross-sectional study included Black South African men (n=380) and women (n=375) who were part of the Middle-Aged Soweto Cohort (MASC). Dual-energy x-ray absorptiometry was used to determine fat mass and visceral adipose tissue, and fasting venous blood samples were collected for analysis of glucose, insulin and C-peptide and for targeted proteomics, measuring a total of 184 pre-selected protein biomarkers. An OGTT was performed on participants without diabetes, and peripheral insulin sensitivity (Matsuda index), HOMA-IR, basal insulin clearance, insulin secretion (C-peptide index) and beta cell function (disposition index) were estimated. Participants were classified as having normal glucose tolerance (NGT; n=546), IGM (n=116) or type 2 diabetes (n=93). Proteins associated with dysglycaemia (IGM or type 2 diabetes) in the MASC were validated in the Swedish EpiHealth cohort (NGT, n=1706; impaired fasting glucose, n=550; type 2 diabetes, n=210). RESULTS: We identified 73 proteins associated with dysglycaemia in the MASC, of which 34 were validated in the EpiHealth cohort. Among these validated proteins, 11 were associated with various measures of insulin dynamics, with the largest number of proteins being associated with HOMA-IR. In sex-specific analyses, IGF-binding protein 2 (IGFBP2) was associated with lower HOMA-IR in women (coefficient -0.35; 95% CI -0.44, -0.25) and men (coefficient -0.09; 95% CI -0.15, -0.03). Metalloproteinase inhibitor 4 (TIMP4) was associated with higher insulin secretion (coefficient 0.05; 95% CI 0.001, 0.11; p for interaction=0.025) and beta cell function (coefficient 0.06; 95% CI 0.02, 0.09; p for interaction=0.013) in women only. In contrast, a stronger positive association between IGFBP2 and insulin sensitivity determined using an OGTT (coefficient 0.38; 95% CI 0.27, 0.49) was observed in men (p for interaction=0.004). A posteriori analysis showed that the associations between TIMP4 and insulin dynamics were not mediated by adiposity. In contrast, most of the associations between IGFBP2 and insulin dynamics, except for insulin secretion, were mediated by either fat mass index or visceral adipose tissue in men and women. Fat mass index was the strongest mediator between IGFBP2 and insulin sensitivity (total effect mediated 40.7%; 95% CI 37.0, 43.6) and IGFBP2 and HOMA-IR (total effect mediated 39.1%; 95% CI 31.1, 43.5) in men. CONCLUSIONS/INTERPRETATION: We validated 34 proteins that were associated with type 2 diabetes, of which 11 were associated with measures of type 2 diabetes pathophysiology such as peripheral insulin sensitivity and beta cell function. This study highlights biomarkers that are similar between cohorts of different ancestry, with different lifestyles and sociodemographic profiles. The African-specific biomarkers identified require validation in African cohorts to identify risk markers and increase our understanding of the pathophysiology of type 2 diabetes in African populations.

Knock-down of IGFBP2 ameliorates lung fibrosis and inflammation in rats with severe pneumonia through STAT3 pathway.

OBJECTIVE: To observe the mechanism of IGFBP2 knock-down in improving lung fibrosis and inflammation through STAT3 pathway in rats with severe pneumonia. MATERIALS AND METHODS: First, SP rat model was established. Then rats were divided into the Control group, the SP group, the SP + Lv-vector shRNA group, the SP + Lv-IGFBP2 shRNA group, the SP + Lv-vector group, and the SP + Lv-IGFBP2 group. The mRNA and protein levels of IGFBP2, NOS, CD206 and Arg 1 were detected by RT-qPCR and Western blot. IHC was used to check the positive expression of IGFBP2 and MCP1. A fully automated blood gas analyzer was used to detected PaCO2, CO2 content, PaO2 and SaO2. HE and Masson staining were performed to observe the lung tissue injury and collagen deposition of rats in each group. ELISA assays were used to calculate the levels of inflammatory factors IL-1ß, IL-6, TNF-α, IL-4, and IL-10. Flow cytometry was conducted to acquire the ratio of M1-type AMs and M2-type AMs. RESULTS: Compared with the Control group, IGFBP2, iNOS, CD206, and Arg1 mRNA and protein expression levels, IGFBP2 and MCP1 positive expressions, PaCO2, p-STAT3/STAT3, p-JAK2/JAK2, IL-1ß, IL-6, and TNF-α levels, the number of AMs and neutrophils, the proportion of M1 type AMs and the expressions of α-SMA, Collagen-I, Collagen III, and Fibronectin were significantly increased in SP rats (p < 0.05), while PaCO2, CO2, and SaO2, IL-4 and IL-10 levels, and the proportion of M2 type AMs decreased (p < 0.05). However, the knockdown of IGFBP2 reversed the above index trends. CONCLUSION: Knock-down of IGFBP2 ameliorated lung injury in SP rats, inhibited inflammation and pulmonary fibrosis, and promoted M2-type transformation of AMs by activating the STAT3 pathway.

N6-methyladenosine-modified HOTAIRM1 promotes vasculogenic mimicry formation in glioma.

Vasculogenic mimicry (VM) has been reported to accelerate angiogenesis in malignant tumors, yet the mechanism underlying VM has not been fully elucidated. N6-methyladenosine (m6A) mainly modulates mRNA fate and affects multiple tumorigenesis. Here, we aimed to investigate m6A-modified HOXA transcript antisense RNA myeloid-specific 1 (HOTAIRM1) in the regulation of glioma-associated VM formation. Gene expression was analyzed by quantitative RT-PCR. Cell viability, metastases, and VM formation capacity were determined by CCK-8, migration and invasion, as well as tube formation assays, respectively. The function and mechanisms of m6A-modified HOTAIRM1 were defined through liquid chromatography-tandem mass spectrometry m6A quantification, methylated RNA immunoprecipitation sequencing, RNA stability assays, and RNA pull-down experiments. A glioma xenograft mouse model was further established for VM evaluation in vivo. The results showed that HOTAIRM1, methyltransferase-like 3 (METTL3), and insulin-like growth factor binding protein 2 (IGFBP2) were upregulated in glioma tissues and cell lines. HOTAIRM1 functions as an oncogene in glioma progression; however, knockdown of HOTAIRM1 significantly reduced cell viability, migration, invasion, and VM formation. Notably, METTL3-dependent m6A modification enhanced HOTAIRM1 mRNA stability, whereas knockdown of METTL3 deficiency significantly suppressed VM in glioma. Moreover, HOTAIRM1 was found to bind IGFBP2, and HOTAIRM1 deficiency blocked glioma progression and VM formation in vivo. Our results indicated that METTL3-dependent m6A-modified HOTAIRM1 promoted VM formation in glioma.

METTL3-mediated HOTAIRM1 promotes vasculogenic mimicry icontributionsn glioma via regulating IGFBP2 expression.

BACKGROUND: HOTAIRM1 is revealed to facilitate the malignant progression of glioma. Vasculogenic mimicry (VM) is critically involved in glioma progression. Nevertheless, the molecular mechanism of HOTAIRM1 in regulating glioma VM formation remains elusive. Thus, we attempted to clarify the role and mechanism of HOTAIRM1 in VM formation in glioma. METHODS: qRT-PCR and western blot assays were used to evaluate the gene and protein expression levels of HOTAIRM1 in glioma patient tissue samples and cell lines. The role of HOTAIRM1 in glioma cell progression and VM formation was explored using a series of function gain-and-loss experiments. RNA-binding protein immunoprecipitation (RIP), RNA pull-down, and mechanism experiments were conducted to assess the interaction between HOTAIRM1/METTL3/IGFBP2 axis. Furthermore, rescue assays were conducted to explore the regulatory function of HOTAIRM1/METTL3/IGFBP2 in glioma cell cellular processes and VM formation. RESULTS: We found that HOTAIRM1 presented up-regulation in glioma tissues and cells and overexpression of HOTAIRM1 facilitated glioma cell proliferation, migration, invasion, and VM formation. Furthermore, overexpression of HOTAIRM1 promoted glioma tumor growth and VM formation capacity in tumor xenograft mouse model. Moreover, HOTAIRM1 was demonstrated to interact with IGFBP2 and positively regulated IGFBP2 expression. IGFBP2 was found to promote glioma cell malignancy and VM formation. Mechanistically, METTL3 was highly expressed in glioma tissues and cells and was bound with HOTAIRM1 which stabilized HOTAIRM1 expression. Rescue assays demonstrated that METTL3 silencing counteracted the impact of HOTAIRM1 on glioma cell malignancy and VM formation capacity. CONCLUSION: HOTAIRM1, post-transcriptionally stabilized by METTL3, promotes VM formation in glioma via up-regulating IGFBP2 expression, which provides a new direction for glioma therapy.

Circulating IGF-1 and IGFBP-2 may be biomarkers for risk stratification in patients with acute coronary syndrome: A prospective cohort study.

BACKGROUND AND AIM: The involvement of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-2 (IGFBP-2) following acute coronary syndrome (ACS) is rarely studied in clinical practice. Therefore, we sought to evaluate the relationship between IGF-1 and IGFBP-2 concentrations at admission and risk stratification based on the Thrombolysis in Myocardial Infarction (TIMI) risk score in patients with ACS. METHODS AND RESULTS: In all, 304 patients diagnosed with ACS were included in this study. Plasma IGF-1 and IGFBP-2 were measured using commercially available ELISA kits. The TIMI risk score was calculated and the study population was stratified into high (n = 65), medium (n = 138), and low (n = 101) risk groups. Levels of IGF-1 and IGFBP-2 were analyzed for their predictive ability of risk stratification based on the TIMI risk scores. Correlation analysis showed that IGF-1 levels were negatively correlated with TIMI risk levels (r = -0.144, p = 0.012), while IGFBP-2 levels were significantly and positively correlated with TIMI risk levels (r = 0.309, p < 0.001). In multivariate logistic regression analysis, IGF-1 (odds ratio [OR]: 0.995; 95% confidence interval [CI]: 0.990-1.000; p = 0.043) and IGFBP-2 (OR: 1.002; 95%CI: 1.001-1.003; p < 0.001) were independent predictors of high TIMI risk levels. In receiver operating characteristic curves, the area under the curve values for IGF-1 and IGFBP-2 in the prediction of high TIMI risk levels were 0.605 and 0.723, respectively. CONCLUSIONS: IGF-1 and IGFBP-2 levels are excellent biomarkers for risk stratification in patients with ACS, which provides further guidance for clinicians to identify patients at high risk and to lower their risk.

Insulin-like growth factor binding protein 2: a core biomarker of left ventricular dysfunction in dilated cardiomyopathy.

BACKGROUND: RNA modifications, especially N6-methyladenosine, N1-methyladenosine and 5-methylcytosine, play an important role in the progression of cardiovascular disease. However, its regulatory function in dilated cardiomyopathy (DCM) remains to be undefined. METHODS: In the study, key RNA modification regulators (RMRs) were screened by three machine learning models. Subsequently, a risk prediction model for DCM was developed and validated based on these important genes, and the diagnostic efficiency of these genes was assessed. Meanwhile, the relevance of these genes to clinical traits was explored. In both animal models and human subjects, the gene with the strongest connection was confirmed. The expression patterns of important genes were investigated using single-cell analysis. RESULTS: A total of 4 key RMRs were identified. The risk prediction models were constructed basing on these genes which showed a good accuracy and sensitivity in both the training and test set. Correlation analysis showed that insulin-like growth factor binding protein 2 (IGFBP2) had the highest correlation with left ventricular ejection fraction (LVEF) (R = -0.49, P = 0.00039). Further validation expression level of IGFBP2 indicated that this gene was significantly upregulated in DCM animal models and patients, and correlation analysis validation showed a significant negative correlation between IGFBP2 and LVEF (R = -0.87; P = 6*10-5). Single-cell analysis revealed that this gene was mainly expressed in endothelial cells. CONCLUSION: In conclusion, IGFBP2 is an important biomarker of left ventricular dysfunction in DCM. Future clinical applications could possibly use it as a possible therapeutic target.

Insulin-like growth factor binding protein-2 as a biomarker for lupus nephritis.

BACKGROUND: Lupus nephritis (LN) is a serious manifestation of systemic lupus erythematosus (SLE). The aim of this study was to identify serum insulin-like growth factor binding protein-2 (IGFBP-2) as a novel non-invasive biomarker for clinical disease and renal pathology in pediatric LN. METHODS: A cross-sectional study on 93 newly diagnosed LN children who were biopsy-proven, 35 SLE children with no renal involvement as disease controls, and 30 healthy controls (HC) with age and gender-matched. All children were ELISA tested for serum IGFBP-2 levels. Clinical, laboratory, histopathological features of LN patients were collected. RESULTS: Compared to SLE or HC, serum IGFBP-2 levels were significantly elevated in LN patients. Serum IGFBP-2 could distinguish LN patients from two others (AUC = 0.937, p < 0.001 for LN vs. HC; 0.897, p < 0.0001 for LN vs. SLE). In ROC analysis, IGFBP-2 had a higher ability to differentiate between LN and SLE than anti-dsDNA with AUC values of 0.895 and 0.643, respectively. LN children with systemic lupus erythematosus disease activity index (SLEDAI) in high activity had significantly higher IGFBP-2 concentration than the others with SLEDAI in moderate activity. Serum IGFBP-2 correlated with albuminemia levels (r = 0.415, p < 0.001), urine protein-to-creatinine levels (r = 0.316, p = 0.002), estimated glomerular filtration rate (r = 0.438, p < 0.001), complement C3 (r = 0.333, p = 0.001). More importantly, serum IGFBP-2 correlated with the activity index of renal pathology (r = 0.312, p = 0.007, n = 75). CONCLUSIONS: Serum IGFBP-2 is a promising biomarker for pediatric lupus nephritis, reflective of disease activity and activity index in renal patients.

Increased IGFBP2 Levels by Placenta-Derived Mesenchymal Stem Cells Enhance Glucose Metabolism in a TAA-Injured Rat Model via AMPK Signaling Pathway.

The insulin resistance caused by impaired glucose metabolism induces ovarian dysfunction due to the central importance of glucose as a source of energy. However, the research on glucose metabolism in the ovaries is still lacking. The objectives of this study were to analyze the effect of PD-MSCs on glucose metabolism through IGFBP2-AMPK signaling and to investigate the correlation between glucose metabolism and ovarian function. Thioacetamide (TAA) was used to construct a rat injury model. PD-MSCs were transplanted into the tail vein (2 × 106) 8 weeks after the experiment started. The expression of the IGFBP2 gene and glucose metabolism factors (e.g., AMPK, GLUT4) was significantly increased in the PD-MSC group compared to the nontransplantation (NTx) group (* p < 0.05). The levels of follicular development markers and the sex hormones AMH, FSH, and E2 were also higher than those in the TAA group. Using ex vivo cocultivation, the mRNA and protein expression of IGFBP2, AMPK, and GLUT4 were significantly increased in the cocultivation with the PD-MSCs group and the recombinant protein-treated group (* p < 0.05). These findings suggest that the increased IGFBP2 levels by PD-MSCs play an important role in glucose metabolism and ovarian function through the IGFBP2-AMPK signaling pathway.

Associations between insulin-like growth factor binding protein-2 and lipoprotein kinetics in men.

Low circulating concentrations of insulin-like growth factor binding protein-2 (IGFBP-2) have been associated with dyslipidemia, notably with high triglyceride (TG) levels. However, the determinants by which IGFBP-2 influences lipoprotein metabolism, especially that of TG-rich lipoproteins (TRLs), are poorly understood. Here, we aimed to assess the relationships between IGFBP-2 levels and lipoprotein production and catabolism in human subjects. Fasting IGFBP-2 concentrations were measured in the plasma of 219 men pooled from previous lipoprotein kinetics studies. We analyzed production rate and fractional catabolic rates of TRLapoB-48, and LDL-, IDL-, and VLDLapoB-100 by multicompartmental modeling of l-[5,5,5-D3] leucine enrichment data after a 12 h primed constant infusion in individuals kept in a constant nutritional steady state. Subjects had an average BMI of 30 kg/m2, plasma IGFBP-2 levels of 157 ng/ml, and TG of 2.2 mmol/l. After adjustments for age and BMI, IGFBP-2 levels were negatively associated with plasma TG (r = -0.29; P < 0.0001) and positively associated with HDL-cholesterol (r = 0.26; P < 0.0001). In addition, IGFBP-2 levels were positively associated with the fractional catabolic rate of VLDLapoB-100 (r = 0.20; P < 0.01) and IDLapoB-100 (r = 0.19; P < 0.05) and inversely with the production rate of TRLapoB-48 (r = -0.28; P < 0.001). These correlations remained statistically significant after adjustments for age, BMI, and the amount of fat given during the tracer infusion. These findings show that the association between low plasma IGFBP-2 and high TG concentrations could be due to both an impaired clearance of apoB-100-containing VLDL and IDL particles and an increased production of apoB-48-containing chylomicrons. Additional studies are necessary to investigate whether and how IGFBP-2 directly impacts the kinetics of TRL.

Hypoxia-inducible lncRNA MIR210HG interacting with OCT1 is involved in glioblastoma multiforme malignancy.

An insufficient oxygen supply within the intratumoral environment, also known as hypoxia, induces glioblastoma multiforme (GBM) invasion, stemness, and temozolomide (TMZ) drug resistance. Long noncoding (lnc)RNAs have been reported to be involved in hypoxia and GBM progression. However, their roles in hypoxic GBM malignancy are still unclear. We investigated the mechanisms of hypoxia-mediated lncRNAs in regulating GBM processes. Using The Cancer Genome Atlas (TCGA) and data mining, hypoxia-correlated lncRNAs were identified. A hypoxia-upregulated lncRNA, MIR210HG, locating in nuclear regions, predicted poor prognoses of patients and modulated hypoxia-promoted glioma stemness, TMZ resistance, and invasion. Depletion of hypoxic MIR210HG suppressed GBM and patient-derived cell growth and increased TMZ sensitivity in vitro and vivo. Using RNA sequencing and gene set enrichment analysis (GSEA), MIR210HG-upregulated genes significantly belonged to the targets of octamer transcription factor 1 (OCT1) transcription factor. The direct interaction between OCT1 and MIR210HG was also validated. Two well-established worse prognostic factors of GBM, insulin-like growth factor-binding protein 2 (IGFBP2) and fibroblast growth factor receptor 1 (FGFR1), were identified as downstream targets of OCT1 through MIR210HG mediation in hypoxia. Consequently, the lncRNA MIR210HG is upregulated by hypoxia and interacts with OCT1 for modulating hypoxic GBM, leading to poor prognoses. These findings might provide a better understanding in functions of hypoxia/MIR210HG signaling for regulating GBM malignancy.

The lysosomal trafficking regulator is necessary for normal wound healing.

Non-healing wounds are a major threat to public health throughout the United States. Tissue healing is complex multifactorial process that requires synchronicity of several cell types. Endolysosomal trafficking, which contributes to various cell functions from protein degradation to plasma membrane repair, is an understudied process in the context of wound healing. The lysosomal trafficking regulator protein (LYST) is an essential protein of the endolysosomal system through an indeterminate mechanism. In this study, we examine the impact of impaired LYST function both in vitro with primary LYST mutant fibroblasts as well as in vivo with an excisional wound model. The wound model shows that LYST mutant mice have impaired wound healing in the form of delayed epithelialization and collagen deposition, independent of macrophage infiltration and polarisation. We show that LYST mutation confers a deficit in MCP-1, IGF-1, and IGFBP-2 secretion in beige fibroblasts, which are critical factors in normal wound healing. Identifying the mechanism of LYST function is important for understanding normal wound biology, which may facilitate the development of strategies to address problem wound healing.

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.

Insulin-like growth factor binding protein 2 null mice (Igfbp2-/-) are protected against trabecular bone loss after vertical sleeve gastrectomy.

BACKGROUND: Bariatric surgery has been shown to result in weight loss, improved hemoglobin A1C, and decreased mortality but can also lead to bone loss and increased fracture rates. Serum IGFBP-2 is elevated in patients after bariatric surgery and although it may lead to improved blood glucose, may also drive bone resorption, and inhibit IGF-I action. This study tested the hypothesis that Igfbp2-/- mice were acutely protected from bone loss after vertical sleeve gastrectomy (VSG). METHODS: Thirty-four mice, 17 Igfbp2-/- and 17 + / + underwent a hand-sewn VSG or sham surgery, at 16 weeks of age. Mice were harvested at 20 weeks of age. DXA was measured for body composition, areal bone mineral density (aBMD), areal bone mineral content (aBMC), femoral bone mineral density (fBMD), and femoral bone mineral content (fBMC) at 15, 18, and 20 weeks of age. Micro-computed tomography and serum ELISA assays were measured and analyzed at 20 weeks of age. RESULTS: Both Igfbp2-/- and + / + mice lost significant weight (P = 0.0251, P = 0.0003, respectively) and total fat mass (P = 0.0082, P = 0.0004, respectively) at 4 weeks after VSG. Igfbp2+/+ mice lost significant aBMD, fBMD, fBMC, trabecular BMD, trabecular BV/TV and cortical tissue mineral density (P = 0.0150, P = 0.0313, P = 0.0190, P = 0.0072, and 0.0320 respectively). The Igfbp2-/- mice did not show significant bone loss in these parameters nor in trabecular BV/TV. Both Igfbp2-/- and + / + mice had less cortical bone area (P = 0.0181, P = < .00001), cortical area over total area (P = 0.0085, P = 0.0007), and cortical thickness (P = 0.0050, P = < 0.0001), respectively. Igfbp2+/+ mice demonstrated significantly lower polar, minimum, and maximum moments of inertia (P = 0.0031, P = 0.0239, and P = 0.0037, respectively). Igfbp2+/+ had significantly higher levels of IGFBP-2 at 2 weeks postoperatively after VSG (P = 0.035), and elevated levels of CTx and P1NP (P = 0.0127, P = 0.0058, respectively). CONCLUSIONS: Igfbp2-/- mice were protected against trabecular bone loss and had attenuated cortical bone loss 4 weeks after VSG.

Changes in circulating insulin-like growth factor-1 and its binding proteins in yearling rainbow trout during spring under natural and manipulated photoperiods and their relationships with gill Na+, K+-ATPase and body size.

Smoltification in salmonids occurs during spring in response to increasing photoperiod to prepare for marine life. Smoltification is associated with increased hypo-osmoregulatory ability and enhanced growth potential, mediated by growth hormone and insulin-like growth factor (IGF)-1. Rainbow trout is uniquely insensitive to the induction of smoltification-associated changes by photoperiod, such as the activation of gill Na+,K+-ATPase (NKA). We measured the circulating IGF-1 and IGF-binding protein (IGFBP)-2b levels in yearling rainbow trout exposed to natural and manipulated photoperiods during spring and correlated these with gill NKA activity and body size. Although the effect of photoperiod manipulation on body size and circulating IGF-1 and IGFBP-2b was negligible, they were positively correlated with gill NKA activity in fish under simulated natural photoperiod. We next pit-tagged yearling rainbow trout and fed them a restricted ration or to satiation under a natural photoperiod. In April, gill NKA activity was higher in the satiation group than in the restricted group and positively correlated with body size and growth rate. In addition, circulating IGFBP-2b was positively correlated with gill NKA, size and growth, whereas circulating IGF-1 was correlated only with size and growth. The relationship between circulating IGF-1 and growth intensified from May to June, suggesting that the IGF-1-growth relationship was disrupted in April when gill NKA was activated. Two additional IGFBPs were related to growth parameters but not to gill NKA activity. The present study suggests that circulating IGFBP-2b and IGF-1 mediate the size-dependent activation of gill NKA in yearling rainbow trout during spring.

Effect of Nellore (Bos indicus) donor age on in-vitro embryo production and pregnancy rate.

The aim of this study was to evaluate the effect of age of Nellore (Bos indicus) donors on the efficiency of in vitro embryo production (IVEP) and pregnancy rate. Thirty-six donors, including 11 female calves (13 ± 0.61 months), 17 prepubertal heifers (25 ± 0.78 months) and 8 cows (83 ± 28 months), were submitted to 3 procedures of ovum pickup (OPU) on random days of the estrous cycle at intervals of 21 days. Caspase-3 and IGFBP2 were quantified in oocytes and blastocysts for the evaluation of oocyte and embryo quality. The produced embryos were vitrified (n = 445) and transferred to synchronized recipients. Cows produced a larger number of follicles (cows: 54.5 ± 6.2; calves: 20.0 ± 0.57; prepubertal heifers: 20.8 ± 0.46), total oocytes (cows: 45.97 ± 7.22; calves: 28.93 ± 6.14; prepubertal heifers: 27.21 ± 4.94) and cleaved oocytes (cows: 21.14 ± 4.22; calves: 13.09 ± 3.72; prepubertal heifers: 12.4 ± 3.19). The cleavage rate was similar between age categories; however, cows tended (p < 0.07) to produce a larger number of blastocysts (9.74 ± 2.26) per OPU than calves (5.57 ± 1.99) and prepubertal heifers tended to have a higher blastocyst yield (35.4%) than calves (27.1%) (p < .07). The expression levels of IGFBP2 and caspase-3 were higher in oocytes derived from calves compared to the other two categories. The pregnancy rate was higher in calves (43.1%) and cows (40.4%) than in prepubertal heifers (33.8%) (p = .03). Despite the larger numbers of follicles and viable oocytes in cows, the blastocyst production results and pregnancy rates obtained indicate that the use of young females as oocyte donors in IVEP is feasible and may contribute to reduce the generation interval.

Pulmonary alveolar type I cell population consists of two distinct subtypes that differ in cell fate.

Pulmonary alveolar type I (AT1) cells cover more than 95% of alveolar surface and are essential for the air-blood barrier function of lungs. AT1 cells have been shown to retain developmental plasticity during alveolar regeneration. However, the development and heterogeneity of AT1 cells remain largely unknown. Here, we conducted a single-cell RNA-seq analysis to characterize postnatal AT1 cell development and identified insulin-like growth factor-binding protein 2 (Igfbp2) as a genetic marker specifically expressed in postnatal AT1 cells. The portion of AT1 cells expressing Igfbp2 increases during alveologenesis and in post pneumonectomy (PNX) newly formed alveoli. We found that the adult AT1 cell population contains both Hopx+Igfbp2+ and Hopx+Igfbp2- AT1 cells, which have distinct cell fates during alveolar regeneration. Using an Igfbp2-CreER mouse model, we demonstrate that Hopx+Igfbp2+ AT1 cells represent terminally differentiated AT1 cells that are not able to transdifferentiate into AT2 cells during post-PNX alveolar regeneration. Our study provides tools and insights that will guide future investigations into the molecular and cellular mechanism or mechanisms underlying AT1 cell fate during lung development and regeneration.

Potential Role of Insulin Growth-Factor-Binding Protein 2 as Therapeutic Target for Obesity-Related Insulin Resistance.

Evidence from observational and in vitro studies suggests that insulin growth-factor-binding protein type 2 (IGFBP2) is a promising protein in non-communicable diseases, such as obesity, insulin resistance, metabolic syndrome, or type 2 diabetes. Accordingly, great efforts have been carried out to explore the role of IGFBP2 in obesity state and insulin-related diseases, which it is typically found decreased. However, the physiological pathways have not been explored yet, and the relevance of IGFBP2 as an important pathway integrator of metabolic disorders is still unknown. Here, we review and discuss the molecular structure of IGFBP2 as the first element of regulating the expression of IGFBP2. We highlight an update of the association between low serum IGFBP2 and an increased risk of obesity, type 2 diabetes, metabolic syndrome, and low insulin sensitivity. We hypothesize mechanisms of IGFBP2 on the development of obesity and insulin resistance in an insulin-independent manner, which meant that could be evaluated as a therapeutic target. Finally, we cover the most interesting lifestyle modifications that regulate IGFBP2, since lifestyle factors (diet and/or physical activity) are associated with important variations in serum IGFBP2.