Activation-dependent expression of the insulin-like growth factor binding protein-2 in human lymphocytes

IGFBP2 function as a novel biomarker for active lupus nephritis

Abstract

In search for new targets for the diagnosis and treatment of lupus nephritis (LN), we employed TMT-liquid chromatography-triple quadrupole mass spectrometry (TMT-LC–MS/MS) combined with RNA-seq and identified a panel of proteins that was dysregulated both at protein level and mRNA level in active LN patients compared with healthy controls. We chose to study the role of IGFBP2 since it is a relatively understudied protein in the context of LN. We further validated that IGFBP2 significantly increased and correlated with SLE activity index in active LN patients. The receiver operator characteristic (ROC) curve suggested that plasma IGFBP2 had a high diagnostic efficiency for distinguishing between inactive and active LN patients (AUC = 0.992; 95% CI = 0.974–1.000; P < 0.001). We demonstrated neutralizing IGFBP2-downregulated CD4⁺ T cell activation, upregulated the ratio of Treg, downregulated AKT/mTOR/4E-BP1 pathway, and significantly improved nephritis in MRL/lpr mice. In all, our work demonstrated IGFBP2 as a biomarker specific for active LN and blocking IGFBP2 could be a new target for treating LN.

Key messages

Plasma IGFBP2 is a promising diagnostic marker for distinguishing stable LN from active LN, and it is also a predictor for the poor prognosis of LN.

Blockade of IGFBP2 can significantly improve the pathological damage of LN.

IGFBP2 may regulate activation of CD4⁺ T and Treg ratio.

Neutralizing IGFBP2 downregulates AKT/mTOR/4E-BP1 pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00109-022-02241-z.

Tumor-derived extracellular vesicles induce invalid cytokine release and exhaustion of CD19 CAR-T Cells

Although CD19 chimeric antigen receptor-T (CAR-T) cells therapy has achieved unparalleled success in B cell malignancies. The dysfunction of CAR-T cells due to exhaustion is considered as a key factor for treatment failure, and the mechanisms of exhaustion remain elusive. Extracellular vesicles (EVs), important media for communication between tumor and immune cells, may contribute to CAR-T cell exhaustion. Here, we demonstrated that CD19⁺ tumor cells derived EVs (NALM6-EVs) can carry CD19 antigen and activate CD19 CAR-T cells. The transient activation induced a supraphysiologic inflammatory state with increased release of multiple cytokines. Besides, the sustained activation led CD19 CAR-T cells to enter an exhausted state with upregulated inhibitory receptors, decreased expansion ability, exaggerated effector cell differentiation and impaired antitumor activity. Transcriptomic profiling validated these findings and identified dynamic changes in CD8⁺ effector T, CD8⁺ exhausted T, CD8⁺RRM2⁺ T and T helper cell subpopulations during activation to exhaustion, as well as changes in many cytokines, inflammatory and immune-related pathways. Our findings identify a credible mechanism of CAR-T cell exhaustion that driven by tumor-derived EVs and provide a novel possible trigger for early cytokine release syndrome.

Immune dysregulation in offspring of a bipolar parent. Altered serum levels of immune growth factors at adolescent age

Immune dysregulation plays a role in the vulnerability for mood disorders. Immune growth factors, such as Stem Cell Factor (SCF), Insulin-like Growth Factor-Binding Protein-2 (IGF-BP2), Epidermal Growth Factor (EGF), IL-7 and sCD25 have repeatedly been reported altered in patients with mood disorders. The aim of this study was to investigate levels of these factors in serum of adolescent bipolar offspring, who have a heightened risk for mood disorder development and to also analyze the data combined with previously published data. Growth factors were assessed by CBA/ELISA in adolescent bipolar offspring (n=96, mean age=16years) and in age- and gender-matched healthy controls (n=50). EGF belonged to a mutually correlating cluster of mainly neurotrophic compounds including S100B and BDNF, which were in general decreased in serum. IL-7, SCF, IGF-BP2 and sCD25, belonged to a different mutually correlating cluster of immune growth factors, which were in general increased: IGF-BP2 significantly in serum of offspring without a mood disorder, IL-7 and SCF in serum of offspring who had experienced a mood episode. This pattern of de- and increases was not different between bipolar offspring that developed or did not develop a mood disorder over time, apart from the IGF-BP2 level, which was near significantly higher in offspring later developing a mood disorder. Correlations with the previously published immune-cellular abnormalities were not found. In conclusion non-affected adolescents at familial mood disorder development risk were characterized by a distinct pattern of a series of compounds operating in a network of hematopoiesis, neurogenesis and inflammation.

A meta-analysis of microarray-based gene expression studies of olfactory bulb-derived olfactory ensheathing cells

Genome wide transcriptional profiling and large scale proteomics have emerged as two powerful methods to dissect the molecular properties of specific neural tissues or cell types on a global scale. Several genome-wide transcriptional profiling and proteomics studies have been published on cultured olfactory ensheathing cells (OEC). In this article we present a meta-analysis of all five published and publicly available micro-array gene expression datasets of cultured early-passage-OB-OEC with other cell types (Schwann cells, late-passage-OB-OEC, mucosa-OEC, an OEC cell line, and acutely dissected OEC). The aim of this meta-analysis is to identify genes and molecular pathways that are found in multiple instead of one isolated study. 454 Genes were detected in at least three out of five microarray datasets. In this "Top-list", genes involved in the biological processes "growth of neurites", "blood vessel development", "migration of cells" and "immune response" were strongly overrepresented. By applying network analysis tools, molecular networks were constructed and Hub-genes were identified that may function as key genes in the above mentioned interrelated processes. We also identified 7 genes (ENTPD2, MATN2, CTSC, PTHLH, GLRX1, COL27A1 and ID2) with uniformly higher or lower expression in early-passage-OB-OEC in all five microarray comparisons. These genes have diverse but intriguing roles in neuroprotection, neurite extension and/or tissue repair. Our meta-analysis provides novel insights into the molecular basis of OB-OEC-mediated neural repair and can serve as a repository for investigators interested in the molecular biology of OEC. This article is part of a Special Issue entitled: Understanding olfactory ensheathing glia and their prospect for nervous system repair.

Molecular and secretory profiles of human mesenchymal stromal cells and their abilities to maintain primitive hematopoietic progenitors

Mesenchymal stromal cells (MSC) provide a supportive cellular microenvironment and are able to maintain the self-renewal capacity of hematopoietic progenitor cells (HPC). Isolation procedures for MSC vary extensively, and this may influence their biologic properties. In this study, we have compared human MSC isolated from bone marrow (BM) using two culture conditions, from cord blood (CB), and from adipose tissue (AT). The ability to maintain long-term culture-initiating cell frequency and a primitive CD34(+)CD38(-) immunophenotype was significantly higher for MSC derived from BM and CB compared with those from AT. These results were in line with a significantly higher adhesion of HPC to MSC from BM and CB versus MSC from AT. We have compared the cytokine production of MSC by cytokine antibody arrays, enzyme-linked immunosorbent assay, and a cytometric bead array. There were reproducible differences in the chemokine secretion profiles of various MSC preparations, but there was no clear concordance with differences in their potential to maintain primitive function of HPC. Global gene expression profiles of MSC preparations were analyzed and showed that adhesion proteins including cadherin-11, N-cadherin, vascular cell adhesion molecule 1, neural cell adhesion molecule 1, and integrins were highly expressed in MSC preparations derived from BM and CB. Thus, MSC from BM and CB are superior to MSC from AT for maintenance of primitive HPC. The latter property is associated with specific molecular profiles indicating the significance of cell-cell junctions but not with secretory profiles. Disclosure of potential conflicts of interest is found at the end of this article.

Effects of insulin-like growth factors and insulin-like growth factor binding protein-2 on the in vitro proliferation of peripheral blood mononuclear cells

Increasing evidence has implicated that insulin-like growth factors (IGFs), polypeptides structurally related to proinsulin, are involved in the function and development of the immune system. To probe the relevance of IGF binding protein 2 (IGFBP-2) in T-cell activation and proliferation, we studied the role of IGFBP-2 in anti-CD3 monoclonal antibody (mAb)-activated peripheral blood mononuclear cells (PBMCs). Secretion of IGF-I, IGF-II, and IGFBP-2 by PBMCs from healthy adult donors was determined by radioimmunoassays (RIAs). The PBMC proliferative response after stimulation with anti-CD3 mAb and exposure to increasing concentrations of IGF-I, IGF-II, IGFBP-2, and anti-IGFBP-2 were determined by bromodeoxyuridine enzyme-linked immunosorbent assay. Observations were tested for significance by paired t-tests. We demonstrate an increase in IGFBP-2 secretion associated with both activation of PBMC by anti-CD3 mAb and increasing cell density. Incubation with exogenous IGFBP-2 increased the proliferation of PBMCs, whereas anti-IGFBP-2 had an antiproliferative effect on PBMCs that was reversed by simultaneous exposure to IGFBP-2. The stimulatory activity of IGFBP-2 (1-10 ng/ml) on anti-CD3 mAb-activated PBMCs was similar to that of IGF-I and IGF-II (1-100 ng/ml), with the mean increase in PBMC proliferative response ranging between 150% and 160% for IGFBP-2 (p = 0.03), 150% and 170% for IGF-I (p < 0.01), 133%-161% for IGF-II (p < 0.01), and 157% and 175% for IGF-I + IGF-II (p < 0.01). Thus, our data strongly suggest a role for IGFBP-2 as a local growth factor contributing to the proliferation and activation of mononuclear cells.

Changes of serum growth factors (IGF-I,-II and IGFBP-2,-3) prior to and after stem cell transplantation in children with acute leukemia

SUMMARY

Insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) may play an important role in tumor proliferation. This study aimed to investigate the IGF system in children with acute leukemia prior to and after hematological stem cell transplantation (HSCT). In 51 patients (AML n=27; ALL n=24; mean age 11.2+/-4.8 years), serum parameters (IGF-I,-II, IGFBP-2,-3) were investigated up to 18 months after HSCT by RIA. Patients with AML showed a significant increase of IGFBP-2 up to 100 days after HSCT (mean +/-s.d. prior to HSCT: 3.2+/-3.6 SDS vs 100 days after HSCT: 5.3 degrees +/-3.4 SDS, P=0.005). Furthermore, IGF-I and IGFBP-3 were significantly decreased (IGF-I: -0.3+/-1.5 vs -0.7 +/-1.2 SDS, P=0.001; IGFBP-3: -0.3+/-1.1 vs -1.0+/-1.1 SDS, P=0.02). Children with AML showed significantly higher IGFBP-2 (P=0.04) and significantly lower IGF-I (P=0.03) and IGFBP-3 (P=0.05) levels than children with ALL at day 100 after HSCT. We conclude that children with acute leukemia show important changes in the IGF system after HSCT. In particular, IGFBP-2 was significantly elevated at day 100 after HSCT. Increased IGFBP-2 and decreased IGF-I and IGFBP-3 may be associated with the increased proliferation rate of transplanted bone marrow.

Novel aspects of the insulin-like growth factor binding proteins

The insulin-like growth factors (IGFs), IGF binding proteins (IGFBPs), and IGFBP proteases regulate somatic growth and cellular proliferation both in vivo and in vitro. IGFs are potent mitogens whose actions are determined by the availability of free IGFs to interact with IGF receptors. IGFBPs comprise a family of six proteins that bind IGFs with high affinity and specificity and thereby regulate IGF-dependent actions. IGFBPs have also recently emerged as IGF-independent regulators of cell growth. Several IGFBP association proteins have been discovered recently which can affect IGFBP action. Cleavage of IGFBPs by specific proteases modulates levels of free IGFs and IGFBPs and thereby their actions. IGFBP-related proteins (IGFBP-rPs) are an emerging group of proteins which bind IGFs with low affinity and also play important roles in cell growth and differentiation. The IGFBPs appear to have emerging roles in the mechanisms underlying human cancer. The GH-IGF-IGFBP axis is complex and powerful. Future research on its physiology promises exciting insights into cell biology as well as advancements in the treatment of a wide range of disease states including cancer, diabetes, vascular disease, asthma, and growth disorders.