Insulin-like growth factor-1 endues monocytes with immune suppressive ability to inhibit inflammation in the intestine

Recombinant IGF-1/BP3 protects against intestinal injury in a neonatal mouse NEC model

BACKGROUND

Recombinant human IGF-1/binding protein-3 (rhIGF-1/BP3) is currently being tested in phase II clinical trials in premature infants to prevent bronchopulmonary dysplasia, but its impact on the neonatal intestine remains unclear. The aim of this study was to determine whether rhIGF-1/BP3 protects against necrotizing enterocolitis (NEC) in mice and to investigate the mechanisms involved.

METHODS

Neonatal mice were dam fed or injected intraperitoneally with rhIGF-1/BP3 (or vehicle) and submitted to an experimental NEC model. Serum IGF-1 was assessed by ELISA and intestinal vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) expression by Western blot. Intestinal endothelial cell proliferation, and enterocyte proliferation and migration were examined by immunofluorescence. Pup survival and histological intestinal injury were determined.

RESULTS

In pups exposed to experimental NEC, serum IBP3-bound IGF-1 level was decreased. Exogenous rhIGF-1/BP3 preserved VEGF and VEGFR2 protein expression, decreased vascular permeability, and preserved endothelial cell proliferation in the small intestine. Furthermore, rhIGF-1/BP3 promoted enterocyte proliferation and migration, which effects were attenuated by inhibiting VEGFR2 signaling, decreased enterocyte apoptosis and decreased systemic and intestinal inflammation. rhIGF-1/BP3 improved survival and reduced the incidence of severe intestinal injury in experimental NEC.

CONCLUSIONS

Exogenous rhIGF-1/BP3 protects neonatal mice against experimental NEC via multiple mechanisms.

IMPACT

Exogenous rhIGF-1/BP3 preserves intestinal microvascular development and integrity, promotes enterocyte proliferation and migration, decreases local and systemic inflammation, and protects neonatal mice against NEC. The article adds pre-clinical evidence of a protective role for rhIGF-1/BP3 on the premature gut. It provides evidence supporting the use of rhIGF1/BP3 in premature neonates to protect against NEC.

GWAS-identified hyperuricemia-associated IGF1R variant rs6598541 has a limited role in urate mediated inflammation in human mononuclear cells

Gout is a common autoinflammatory joint diseases characterized by deposition of monosodium urate (MSU) crystals which trigger an innate immune response mediated by inflammatory cytokines. IGF1R is one of the loci associated with both urate levels and gout susceptibility in GWAS to date, and IGF-1-IGF-1R signaling is implicated in urate control. We investigate the role of IGF-1/IGF1R signaling in the context of gouty inflammation. Also, we test the gout and urate-associated IGF1R rs6598541 polymorphism for association with the inflammatory capacity of mononuclear cells. For this, freshly isolated human peripheral blood mononuclear cells (PBMCs) were exposed to recombinant IGF-1 or anti-IGF1R neutralizing antibody in the presence or absence of solubilized urate, stimulated with LPS/MSU crystals. Also, the association of rs6598541 with IGF1R and protein expression and with ex vivo cytokine production levels after stimulation with gout specific stimuli was tested. Urate exposure was not associated with IGF1R expression in vitro or in vivo. Modulation of IGF1R did not alter urate-induced inflammation. Developing urate-induced trained immunity in vitro was not influenced in cells challenged with IGF-1 recombinant protein. Moreover, the IGF1R rs6598541 SNP was not associated with cytokine production. Our results indicate that urate-induced inflammatory priming is not regulated by IGF-1/IGF1R signaling in vitro. IGF1R rs6598541 status was not asociated with IGF1R expression or cytokine production in primary human PBMCs. This study suggests that the role of IGF1R in gout is tissue-specific and may be more relevant in the control of urate levels rather than in inflammatory signaling in gout.

In Vivo Treatment with Insulin-like Growth Factor 1 Reduces CCR5 Expression on Vaccine-Induced Activated CD4+ T-Cells

At the heart of the DNA/ALVAC/gp120/alum vaccine's efficacy in the absence of neutralizing antibodies is a delicate balance of pro- and anti-inflammatory immune responses that effectively decreases the risk of SIVmac251 acquisition in macaques. Vaccine efficacy is linked to antibodies recognizing the V2 helical conformation, DC-10 tolerogenic dendritic cells eliciting the clearance of apoptotic cells via efferocytosis, and CCR5 downregulation on vaccine-induced gut homing CD4+ cells. RAS activation is also linked to vaccine efficacy, which prompted the testing of IGF-1, a potent inducer of RAS activation with vaccination. We found that IGF-1 changed the hierarchy of V1/V2 epitope recognition and decreased both ADCC specific for helical V2 and efferocytosis. Remarkably, IGF-1 also reduced the expression of CCR5 on vaccine-induced CD4+ gut-homing T-cells, compensating for its negative effect on ADCC and efferocytosis and resulting in equivalent vaccine efficacy (71% with IGF-1 and 69% without).

Intermediate Monocytes and Circulating Endothelial Cells: Interplay with Severity of Atherosclerosis in Patients with Coronary Artery Disease and Type 2 Diabetes Mellitus

The aim was to investigate the association of monocyte heterogeneity and presence of circulating endothelial cells with the severity of coronary atherosclerosis in patients with coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM). We recruited 62 patients with CAD, including 22 patients with DM2. The severity of atherosclerosis was evaluated using Gensini Score. Numbers of classical (CD14++CD16-), intermediate (CD14++CD16+), and non-classical (CD14+CD16++) monocyte subsets; circulating endothelial progenitor cells; and the presence of circulating endothelial cells were evaluated. Counts and frequencies of intermediate monocytes, but not glycaemia parameters, were associated with the severity of atherosclerosis in diabetic CAD patients (rs = 0.689; p = 0.001 and rs = 0.632; p = 0.002, respectively). Frequency of Tie2+ cells was lower in classical than in non-classical monocytes in CAD patients (p = 0.007), while in patients with association of CAD and T2DM, differences between Tie2+ monocytes subsets disappeared (p = 0.080). Circulating endothelial cells were determined in 100% of CAD+T2DM patients, and counts of CD14++CD16+ monocytes and concentration of TGF-β predicted the presence of circulating endothelial cells (sensitivity 92.3%; specificity 90.9%; AUC = 0.930). Thus, intermediate monocytes represent one of the key determinants of the appearance of circulating endothelial cells in all the patients with CAD, but are associated with the severity of atherosclerosis only in patients with association of CAD and T2DM.

[Mechanism of Der f 1/IGF-1 nanoparticle promoting the production of regulatory T cell]

Objective:To prepare PLGA nanoparticles loaded with Der f 1/IGF-1（Der f 1/IGF-1 NPs） and investigate their role in promoting the formation of Treg cells. Methods:NPs coated with Der f 1/IGF-1 were prepared by double emulsion method and their physicochemical properties and cumulative release rate in vitro were analyzed. After pretreatment, BMDC was divided into Saline group, Blank NPs group, Der f 1/IGF-1 group and Der f 1/IGF-1 NPs group. Determination of the expression of IL-10 and TGF-β in BMDC by ELISA. The number of Treg cells was detected by flow cytometry. Results:The results showed that Der f 1/IGF-1 NPs were spherical structures, with good dispersion, particle size less than 200 nm, negative charge and stable slow-release effect of Zeta potential. After BMDC pretreatment, the expression levels of TGF-β and IL-10 in BMDC cells in the Der f 1/IGF-1 NPs group were significantly increased compared with the Blank NPs group, and the difference was statistically significant（P<0.001）. After co-culture with CD4+ T cells, the proportion of Treg cells produced in the Der f 1/IGF-1 NPs group was significantly increased, and the difference was statistically significant（P<0.001）. Conclusion:Der f 1/IGF-1 NPs can induce Treg cell generation in vitro. This study provides a new and more effective method for the reconstruction of immune tolerance dysfunction.

3-aminobenzamide protects against colitis associated diabetes mellitus in male BALB/c mice: Role of PARP-1, NLRP3, SIRT-1, AMPK

Diabetes and ulcerative colitis are chronic diseases associated with inflammation, dysbiosis, impaired immune function and infection risk. In patients with type 1 diabetes enteropathy, gastrointestinal manifestations are seen relatively frequently. The current investigation was aimed to decipher the role of 3-aminobenzamide (3-AB) in ulcerative colitis associated Diabetes mellitus in male BALB/c mice. Ulcerative colitis associated Diabetes mellitus experimental murine model was developed by 3 cycles (each cycle consists of seven days) of Dextran Sulphate Sodium (DSS; 2.5 %w/v) with recovery time of one week in-between along with Streptozotocin (STZ; 40 mg/kg; i.p. x 5 days; consecutively) was given at the I^st recovery period. As an intervention, 3-aminobenzamide (3-AB; 5 and 10 mg/kg; intraperitoneally) was given beginning with the second DSS cycle and then continue till sacrifice. 3-aminobenzamide treatment significantly reduced the severity of colitis-associated diabetes mellitus by altering the expression of a number of molecular targets, including sirtuin 1 (SIRT 1), proliferating cell nuclear antigen (PCNA), poly[ADP-ribose] polymerase 1 (PARP-1), cysteine protease-1 (Caspase-1), nuclear factor kappa-light-chain-enhancer of activated B cells (NFkBp65), NLR family pyrin domain containing 3 (NLRP3), insulin growth factor 1 (IGF-1), interleukin-1β (IL-1β), interleukin-10 (IL-10) and β-catenin. Further, 3-AB at high dose (10 mg/kg; intraperitoneally) significantly restored the epithelial tight junction integrity as evaluated by TEM analysis and restored occludin expression analysed by immunofluorescence analysis. Present study revealed that the high dose of 3-AB (10 mg/kg; intraperitoneally) showed significant and consistent protective effects against colitis associated Diabetes mellitus by modulating various molecular targets.

Insulin-like growth factor-1 receptor controls the function of CNS-resident macrophages and their contribution to neuroinflammation

Signaling by insulin-like growth factor-1 (IGF-1) is essential for the development of the central nervous system (CNS) and regulates neuronal survival and myelination in the adult CNS. In neuroinflammatory conditions including multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), IGF-1 can regulate cellular survival and activation in a context-dependent and cell-specific manner. Notwithstanding its importance, the functional outcome of IGF-1 signaling in microglia/macrophages, which maintain CNS homeostasis and regulate neuroinflammation, remains undefined. As a result, contradictory reports on the disease-ameliorating efficacy of IGF-1 are difficult to interpret, together precluding its potential use as a therapeutic agent. To fill this gap, we here investigated the role of IGF-1 signaling in CNS-resident microglia and border associated macrophages (BAMs) by conditional genetic deletion of the receptor Igf1r in these cell types. Using a series of techniques including histology, bulk RNA sequencing, flow cytometry and intravital imaging, we show that absence of IGF-1R significantly impacted the morphology of both BAMs and microglia. RNA analysis revealed minor changes in microglia. In BAMs however, we detected an upregulation of functional pathways associated with cellular activation and a decreased expression of adhesion molecules. Notably, genetic deletion of Igf1r from CNS-resident macrophages led to a significant weight gain in mice, suggesting that absence of IGF-1R from CNS-resident myeloid cells indirectly impacts the somatotropic axis. Lastly, we observed a more severe EAE disease course upon Igf1r genetic ablation, thus highlighting an important immunomodulatory role of this signaling pathway in BAMs/microglia. Taken together, our work shows that IGF-1R signaling in CNS-resident macrophages regulates the morphology and transcriptome of these cells while significantly decreasing the severity of autoimmune CNS inflammation.

Gut-brain communication in COVID-19: molecular mechanisms, mediators, biomarkers, and therapeutics

INTRODUCTION

Infection with COVID-19 results in acute respiratory symptoms followed by long COVID multi-organ effects presenting with neurological, cardiovascular, musculoskeletal, and gastrointestinal (GI) manifestations. Temporal relationship between gastrointestinal and neurological symptoms is unclear but warranted for exploring better clinical care for COVID-19 patients.

AREAS COVERED

We critically reviewed the temporal relationship between gut-brain axis after SARS-CoV-2 infection and the molecular mechanisms involved in neuroinvasion following GI infection. Mediators are identified that could serve as biomarkers and therapeutic targets in SARS-CoV-2. We discussed the potential therapeutic approaches to mitigate the effects of GI infection with SARS-CoV-2.

EXPERT OPINION

Altered gut microbiota cause increased expression of various mediators, including zonulin causing disruption of tight junction. This stimulates enteric nervous system and signals to CNS precipitating neurological sequalae. Published reports suggest potential role of cytokines, immune cells, B(0)AT1 (SLC6A19), ACE2, TMRSS2, TMPRSS4, IFN-γ, IL-17A, zonulin, and altered gut microbiome in gut-brain axis and associated neurological sequalae. Targeting these mediators and gut microbiome to improve immunity will be of therapeutic significance. In-depth research and well-designed large-scale population-based clinical trials with multidisciplinary and collaborative approaches are warranted. Investigating the temporal relationship between organs involved in long-term sequalae is critical due to evolving variants of SARS-CoV-2.

Survival of HT29 Cancer Cells Is Affected by IGF1R Inhibition via Modulation of Self-DNA-Triggered TLR9 Signaling and the Autophagy Response

Purpose: In HT29 colon cancer cells, a close interplay between self-DNA-induced TLR9 signaling and autophagy response was found, with remarkable effects on cell survival and differentiation. IGF1R activation drives the development and malignant progression of colorectal cancer. IGF1R inhibition displays a controversial effect on autophagy. The interrelated roles of IGF1R inhibition and TLR9/autophagy signaling in HT29 cancer cells have not yet been clarified. In our study, we aimed to investigate the complex interplay of IGF1R inhibition and TLR9/autophagy signaling in HT29 cells. Methods: HT29 cells were incubated with tumor-originated self-DNA with or without inhibitors of IGF1R (picropodophyllin), autophagy (chloroquine), and TLR9 (ODN2088), respectively. Cell proliferation and metabolic activity measurements, direct cell counting, NanoString and Taqman gene expression analyses, immunocytochemistry, WES Simple Western blot, and transmission electron microscopy investigations were performed. Results: The concomitant use of tumor-derived self-DNA and IGF1R inhibitors displays anti-proliferative potential, which can be reversed by parallel TLR9 signaling inhibition. The distinct effects of picropodophyllin, ODN2088, and chloroquine per se or in combination on HT29 cell proliferation and autophagy suggest that either the IGF1R-associated or non-associated autophagy machinery is "Janus-faced" regarding its actions on cell proliferation. Autophagy, induced by different combinations of self-DNA and inhibitors is not sufficient to rescue HT29 cells from death but results in the survival of some CD133-positive stem-like HT29 cells. Conclusion: The creation of new types of combined IGF1R, autophagy, and/or TLR9 signaling inhibitors would play a significant role in the development of more personalized anti-tumor therapies for colorectal cancer.

Survival of HT29 cancer cells is influenced by hepatocyte growth factor receptor inhibition through modulation of self-DNA-triggered TLR9-dependent autophagy response

HGFR activation drives the malignant progression of colorectal cancer, and its inhibition displays anti-autophagic activity. The interrelated role of HGFR inhibition and TLR9/autophagy signaling in HT29 cancer cells subjected to modified self-DNA treatments has not been clarified. We analyzed this complex interplay with cell metabolism and proliferation measurements, TLR9, HGFR and autophagy inhibitory assays and WES Simple Western blot-based autophagy flux measurements, gene expression analyses, immunocytochemistry, and transmission electron microscopy. The overexpression of MyD88 and caspase-3 was associated with enhanced HT29 cell proliferation, suggesting that incubation with self-DNAs could suppress the apoptosis-induced compensatory cell proliferation. HGFR inhibition blocked the proliferation-reducing effect of genomic and hypermethylated, but not that of fragmented DNA. Lowest cell proliferation was achieved with the concomitant use of genomic DNA, HGFR inhibitor, and chloroquine, when the proliferation stimulating effect of STAT3 overexpression could be outweighed by the inhibitory effect of LC3B, indicating the putative involvement of HGFR-mTOR-ULK1 molecular cascade in HGFR inhibitor-mediated autophagy. The most intense cell proliferation was caused by the co-administration of hypermethylated DNA, TLR9 and HGFR inhibitors, when decreased expression of both canonical and non-canonical HGFR signaling pathways and autophagy-related genes was present. The observed ultrastructural changes also support the context-dependent role of HGFR inhibition and autophagy on cell survival and proliferation. Further investigation of the influence of the studied signaling pathways and cellular processes can provide a basis for novel, individualized anti-cancer therapies.

Growth Hormone Overexpression Induces Hyperphagia and Intestinal Morphophysiological Adaptations to Improve Nutrient Uptake in Zebrafish

The excess of circulating growth hormone (GH) in most transgenic animals implies mandatory growth resulting in higher metabolic demand. Considering that the intestine is the main organ responsible for the digestion, absorption, and direction of dietary nutrients to other tissues, this study aimed to investigate the mechanisms by which gh overexpression modulates the intestine to support higher growth. For this purpose, we designed an 8-weeks feeding trial to evaluate growth parameters, feed intake, and intestinal morphometric indices in the adult gh-transgenic zebrafish (Danio rerio) model. To access the sensitivity of the intestine to the excess of circulating GH, the messenger RNA (mRNA) expression of intestine GH receptors (GHRs) (ghra and ghrb) was analyzed. In addition, the expression of insulin-like growth factor 1a (igf1a) and genes encoding for di and tripeptide transporters (pept1a and pept1b) were assessed. Gh-transgenic zebrafish had better growth performance and higher feed intake compared to non-transgenic sibling controls. Chronic excess of GH upregulates the expression of its cognate receptor (ghrb) and the main growth factor related to trophic effects in the intestine (igf1a). Moreover, transgenic zebrafish showed an increased intestinal absorptive area and higher expression of crucial genes related to the absorption of products from meal protein degradation. These results reinforce the ability of GH to modulate intestinal morphology and the mechanisms of assimilation of nutrients to sustain the energy demand for the continuous growth induced by the excess of circulating GH.

Insulin/IGF-1 signaling promotes immunosuppression via the STAT3 pathway: impact on the aging process and age-related diseases

BACKGROUND

The insulin/IGF-1 signaling pathway has a major role in the regulation of longevity both in Caenorhabditis elegans and mammalian species, i.e., reduced activity of this pathway extends lifespan, whereas increased activity accelerates the aging process. The insulin/IGF-1 pathway controls protein and energy metabolism as well as the proliferation and differentiation of insulin/IGF-1-responsive cells. Insulin/IGF-1 signaling also regulates the functions of the innate and adaptive immune systems. The purpose of this review was to elucidate whether insulin/IGF-1 signaling is linked to immunosuppressive STAT3 signaling which is known to promote the aging process.

METHODS

Original and review articles encompassing the connections between insulin/IGF-1 and STAT3 signaling were examined from major databases including Pubmed, Scopus, and Google Scholar.

RESULTS

The activation of insulin/IGF-1 receptors stimulates STAT3 signaling through the JAK and AKT-driven signaling pathways. STAT3 signaling is a major activator of immunosuppressive cells which are able to counteract the chronic low-grade inflammation associated with the aging process. However, the activation of STAT3 signaling stimulates a negative feedback response through the induction of SOCS factors which not only inhibit the activity of insulin/IGF-1 receptors but also that of many cytokine receptors. The inhibition of insulin/IGF-1 signaling evokes insulin resistance, a condition known to be increased with aging. STAT3 signaling also triggers the senescence of both non-immune and immune cells, especially through the activation of p53 signaling.

CONCLUSIONS

Given that cellular senescence, inflammaging, and counteracting immune suppression increase with aging, this might explain why excessive insulin/IGF-1 signaling promotes the aging process.

IGF-1-Expressing Placenta-Derived Mesenchymal Stem Cells Promote Scalding Wound Healing

BACKGROUND

Stem cell-based regenerative therapy is a novel approach to severe damaged skin. Perinatal tissues such as placenta are considered as promising alternatives. The present study aimed to investigate the effect of insulin-like growth factor-1 (IGF-1)-expressing placenta-derived mesenchymal stem cells (hPMSCs) on healing of burn wounds.

MATERIALS AND METHODS

hPMSCs were isolated from human placenta, and IGF-1 was transducted into hPMSCs via lentivirus. Flow cytometry and MTT assay were performed to assess cell apoptosis and viability, respectively. Immunostaining of CK19 and ki67 was for evaluating epithelial differentiation ability and cell proliferation. For in vivo studies, we established a mouse model of scalding and performed local administration of IGF-1-expressing hPMSCs via subcutaneous injection. Wound histology was analyzed with H&E staining. The expression of fibrogenic cytokines was detected by western blot. The production of pro-inflammatory factors was measured by ELISA.

RESULTS

Overexpression of IGF-1 promoted cell proliferation and epithelial differentiation of hPMSCs in vitro and in vivo. Mice with burn injury displayed increased wound contraction and healing rates following treatment with IGF-1-expressing hPMSCs. There was less inflammatory infiltration and reduced collagen disposition in the presence of IGF-1 at the wound site. Administration of IGF-1-expressing hPMSCs suppressed inflammation by decreasing the levels of pro-inflammatory cytokines including tumor necrosis factor-α, interleukin-1β, and interleukin-6. Besides, IGF-1 increased VEGF expression, and decreased TGF-β1, collagen I and collagen III expressions in vivo.

CONCLUSIONS

IGF-1-expressing PMSCs promotes cell proliferation and epithelial differentiation, inhibits inflammation and collagen deposition, and thus contributes to wound healing.

Insulin-Like Growth Factor Gene Polymorphisms Predict Clinical Course in Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is challenged by significant toxicities that are propagated by systemic inflammation caused by cytotoxic damage. Insulin-like growth factor-1 (IGF-1) is key in repair of most tissues and is to a large extent genetically determined. We investigated eight single nucleotide polymorphisms (SNPs) in the genes encoding IGF-1 and its binding protein (IGFBP3) in 543 patients undergoing HSCT to access their impact on systemic inflammation and clinical outcomes. Overall, median serum levels of both IGF-1 and IGFBP3 were found reduced from the referral until 2 years post-HSCT compared with healthy sex- and age-matched individuals, but, for individuals homozygous of the known high-producer minor allele of rs1520220 (IGF1), rs978458 (IGF1), or rs2854744 (IGFBP3) serum levels remained normal during the whole period. In accordance, maximum C-reactive protein levels were lower for these genotypes of IGF1 (rs1520220: median 66 vs. 102 mg/L, P = 0.005 and rs978458: 53 vs. 104 mg/L, P < 0.001), translating into borderline significant superior survival (P = 0.060 for rs1520220) and reduced treatment-related mortality (P = 0.050 for rs978458). In conclusion, we found that three SNPs in the IGF-1 axis with known functional impact were associated with circulating IGF-1 or IGFBP-3 levels also in the setting of HSCT, and predictive of the severity of the toxic-inflammatory response during the treatment.

Platelet-Rich Plasma Therapy Enhances the Beneficial Effect of Bone Marrow Stem Cell Transplant on Endometrial Regeneration

This study aimed to investigate the potential effect of platelet-rich plasma (PRP) therapy on treatment using bone marrow stem cell (BMSC) transplant for uterine horn damage, and to reveal the potential underlying molecular mechanism. Uterine horn damage was established in a rat model, which can be repaired by transplant using BMSCs receiving control or PRP treatment. Immunohistochemistry was conducted to evaluate thickness and expression of α-SMA and vWF in the regenerated endometrium tissues. mRNA and proteins of insulin-like growth factor-1 (IGF-1) and interleukin-10 (IL-10) were measured both in the regenerated endometrium tissues and in cultured BMSCs to evaluate the effect of PRP treatment on their expression. Enzyme-linked immunosorbent assay was employed to measure the secretory levels of IL-10 in cultured BMSCs. Multi-differentiation assays were performed to address the effect of PRP treatment on tri-lineage potential of cultured BMSCs. Chromatin immunoprecipitation and luciferase reporter assays were applied to analyze NF-κB subunit p50 binding on IL-10 promoter and the resulted regulatory effect. PRP treatment significantly improved the efficacy of BMSC transplant in repairing uterine horn damage of rats, and elevated IGF-1 and IL-10 expression in regenerated endometrium tissues and cultured BMSCs, as well as enhanced tri-lineage differentiation potential of BMSCs. On the other hand, p50 inhibition and silencing suppressed the PRP-induced expression and secretion of IL-10 without affecting IGF-1 in the BMSCs. Furthermore, p50 was able to directly bind to IL-10 promoter to promote its expression. Data in the current study propose a working model, where PRP therapy improves endometrial regeneration of uterine horn damage in rats after BMSC transplant therapy, likely mediated through the NF-κB signaling pathway subunit p50 to directly induce the expression and production of IL-10.

Dural Cells Release Factors Which Promote Cancer Cell Malignancy and Induce Immunosuppressive Markers in Bone Marrow Myeloid Cells

BACKGROUND

Thirty per cent of cancer patients develop spine metastases with a substantial number leading to spinal cord compression and neurological deficits. Many demonstrate a propensity toward metastasis to the posterior third of the vertebral body. The dura, the outer layer of the meninges, lies in intimate contact with the posterior border of the vertebral body and has been shown to influence adjacent bone. The effects of the dura on bone marrow and cancer cells have not been examined. Understanding the biology of spinal metastasis will provide insights into mechanisms of cancer growth and allow for new treatment strategies.

OBJECTIVE

To examine the extent to which dura influences bone marrow/tumor cell metastatic characteristics.

METHODS

Dura conditioned media (DCM) from primary dura was examined for the ability to stimulate tumor cell proliferation/invasion and to alter bone marrow cell populations. RNA sequencing of dural fibroblasts was performed to examine expression of cytokines and growth factors.

RESULTS

DCM induced a significant increase in invasion and proliferation of multiple tumor cell lines, and of patient-derived primary spinal metastatic cells. DCM also increased the proliferation of bone marrow myeloid cells, inducing expression of immunosuppressive markers. RNA sequencing of dural fibroblasts demonstrated abundant expression of cytokines and growth factors involved in cancer/immune pathways.

CONCLUSION

Factors released by primary dural cells induce proliferation of tumor cells and alter bone marrow to create a fertile environment for tumor growth. The dura therefore may play an important role in the increased incidence of metastases to adjacent bone.

Vasoactive intestinal peptide is required in the maintenance of immune regulatory competency of immune regulatory monocytes

Dysfunction of the immune regulatory system plays an important role in the pathogenesis of rheumatoid arthritis (RA). Vasoactive intestinal peptide (VIP) has multiple bioactivities. This study aims to investigate the role of VIP in the maintenance of the immune regulatory capacity of monocytes (Mos). Human peripheral blood samples were collected from RA patients and healthy control (HC) subjects. Mos and CD14⁺ CD71^- CD73⁺ CD25⁺ regulatory Mos (RegMos) were isolated from the blood samples and characterized by flow cytometry. A rat RA model was developed to test the role of VIP in the maintenance of the immune regulatory function of Mos. The results showed that RegMos of HC subjects had immune suppressive functions. RegMos of RA patients expressed less interleukin (IL)-10 and showed an incompetent immune regulatory capacity. Serum levels of VIP were lower in RA patients, which were positively correlated with the expression of IL-10 in RegMos. In-vitro experiments showed that the IL-10 mRNA decayed spontaneously in RegMos, which could be prevented by the presence of VIP in the culture. VIP suppressed the effects of tristetraprolin (TTP) on inducing IL-10 mRNA decay in RegMos. Administration of VIP inhibited experimental RA in rats through restoring the IL-10 expression in RegMos. RegMos have immune suppressive functions. VIP is required in maintaining IL-10 expression in RegMos. The data suggest that VIP has translational potential in the treatment of immune disorders such as RA.

Cross-talk between insulin signalling and LPS responses in mouse macrophages

The effect of insulin priming on Il-10 expression, regulation of inflammatory cytokines and participation of intra-cellular signalling events, primarily ERK1/2 and PI3K/Akt, has been investigated in high glucose (HG) and/or lipopolysaccharide (LPS)-induced murine macrophages. Our results demonstrate that congruent with sharp increase in ERK1/2 and CREB phosphorylation, insulin stimulation in vitro promotes significant increase in Il-10 expression in mouse peritoneal macrophage and RAW 264.7 cells, both positive for anti-IRβ. Pharmacological inhibition of MEK/MAPK, but not PI3K/Akt cascade, abrogates CREB phosphorylation and Il-10 synthesis indicating functional relevance of insulin action. Conversely, priming with PI3K inhibitor wortmannin prevents insulin attenuation of HG- and/or LPS-induced p38 MAPK and NF-κB activation, Tnf-α, Il-1β expression as well as NO production. Congruent with reduced Il-10 expression, MEK inhibition abrogates insulin action allowing significant increase in Tlr4 expression and LPS response indicating insulin-induced Il-10 might have pivotal influence in regulation of chronic as well as acute inflammatory response.

Intestinal epithelial cell-specific IGF1 promotes the expansion of intestinal stem cells during epithelial regeneration and functions on the intestinal immune homeostasis

It is well known that insulin-like growth factor 1 (IGF1) acts as a trophic factor in small intestine under both physiological and pathophysiological conditions. However, it still lacks direct in vivo evidence of the functions of intestinal epithelial cell (IEC)-specific IGF1 under both normal and pathological conditions. Using IEC-specific IGF1-knockout (cKO) mice and Lgr5-eGFP-CreERT mice, we demonstrate that IEC-specific IGF1 can enhance nutrient uptake, reduce protein catabolism and energy consumption, and promote the proliferation and expansion of intestinal epithelial cells, including intestinal epithelial stem cells and intestinal secretory cells. Next, we showed that IEC-specific IGF1 renders IECs resistant to irradiation and promotes epithelial regeneration. Strikingly, transcriptome profiling assay revealed that many differentially expressed genes involved in the differentiation and maturation of lymphoid lineages were significantly suppressed in the cKO mice as compared with the control mice. We demonstrated that deletion of IGF1 in IECs enhances bacterial translocation to the mesenteric lymph nodes and liver. Furthermore, high-throughput sequencing of 16S ribosomal RNA genes of gut microbiota revealed that IEC-specific IGF1 loss profoundly affected the gut microbial composition at various levels of classification. Therefore, our findings shed light on the in vivo roles of IEC-specific IGF1 in intestinal homeostasis, epithelial regeneration, and immunity, broadening our current insights on IGF1 functions.

IGF1 receptor and thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is a vexing and poorly understood autoimmune process involving the upper face and tissues surrounding the eyes. In TAO, the orbit can become inflamed and undergo substantial remodeling that is disfiguring and can lead to loss of vision. There are currently no approved medical therapies for TAO, the consequence of its uncertain pathogenic nature. It usually presents as a component of the syndrome known as Graves' disease where loss of immune tolerance to the thyrotropin receptor (TSHR) results in the generation of activating antibodies against that protein and hyperthyroidism. The role for TSHR and these antibodies in the development of TAO is considerably less well established. We have reported over the past 2 decades evidence that the insulin-like growth factorI receptor (IGF1R) may also participate in the pathogenesis of TAO. Activating antibodies against IGF1R have been detected in patients with GD. The actions of these antibodies initiate signaling in orbital fibroblasts from patients with the disease. Further, we have identified a functional and physical interaction between TSHR and IGF1R. Importantly, it appears that signaling initiated from either receptor can be attenuated by inhibiting the activity of IGF1R. These findings underpin the rationale for therapeutically targeting IGF1R in active TAO. A recently completed therapeutic trial of teprotumumab, a human IGF1R inhibiting antibody, in patients with moderate to severe, active TAO, indicates the potential effectiveness and safety of the drug. It is possible that other autoimmune diseases might also benefit from this treatment strategy.

Insulin growth factor-1 correlates with higher bone mineral density and lower inflammation status in obese adult subjects

PURPOSE

Obesity is a severe public health problem worldwide, leading to an insulin-resistant state in liver, adipose, and muscle tissue, representing a risk factor for type 2 diabetes mellitus, cardiovascular diseases, and cancer. We have shown that abdominal obesity is associated with homeostasis derangement, linked to several hormonal and paracrine factors. Data regarding potential link between GH/IGF1 axis, bone mineral density, and inflammation in obesity are lacking. Thus, aim of this study was to evaluate correlation among IGF-1, BMD, and inflammation in obese individuals.

METHODS

The study included 426 obese subjects, mean age 44.8 ± 14 years; BMI 34.9 ± 6.1. Exclusion criteria were chronic medical conditions, use of medications affecting bone metabolism, hormonal and nutritional status, recent weight loss, and prior bariatric surgery. Patients underwent measurements of BMD and body composition by DEXA and were evaluated for hormonal, metabolic profile, and inflammatory markers.

RESULTS

In this population, IGF-1 was inversely correlated with abdominal FM% (p < 0.001, r ² = 0.12) and directly correlated with osteocalcin (OSCA) (p < 0.002, r ² = 0.14). A negative correlation was demonstrated between IGF-1 levels and nonspecific inflammatory index, such as fibrinogen (p < 0.01, r ² = 0.04) and erythrocyte sedimentation rate (p < 0.0001, r ² = 0.03). IGF-1 was directly correlated with higher BMD, at both lumbar (p < 0.02, r ² = 0.03) and femoral site (p < 0.04, r ² = 0.03).

CONCLUSIONS

In conclusion, our results show that higher levels of serum IGF-1 in obese patients correlate with lower inflammatory pattern and better skeletal health, as demonstrated by higher BMD and osteocalcin levels. These results lead to speculate the existence of a bone-adipose-muscle interplay modulating energy homeostasis, glucose, bone metabolism, and chronic inflammation in individuals affected by abdominal obesity.

Insulin-like growth factor 1 inversely relates to monocyte/macrophage activation markers in HIV

OBJECTIVE

Monocyte/macrophage activation is increased among people with HIV, and may contribute to the heightened risk of atherosclerosis and neurocognitive dysfunction in this population. Insulin-like growth factor 1 (IGF-1) has been shown to attenuate the innate immune response in animal models of atherosclerosis and inflammatory bowel disease. We investigated, for the first time, relationships of circulating IGF-1 with monocyte/macrophage-specific indices among HIV-infected individuals and uninfected controls.

DESIGN

Observational.

METHODS

One hundred and thirty-one HIV-infected patients and 65 well matched controls without known cardiac disease or viral hepatitis were recruited previously. IGF-1, expressed as a z-score relative to the age-adjusted and sex-adjusted population mean, was related to log-transformed inflammatory markers within HIV and non-HIV groups.

RESULTS

In HIV, IGF-1 inversely related to sCD163 (r = -0.28, P = 0.002), sCD14 (r = -0.29, P = 0.002), and high-sensitivity IL-6 (r = -0.27, P = 0.006). There was no association of IGF-1 with high-sensitivity CRP, MCP-1, IL-18, or LPS in HIV, or between IGF-1 and any inflammatory marker in controls. Relationships of IGF-1 with sCD163 and sCD14 remained significant in HIV after controlling for age, sex, smoking, BMI, visceral fat, statin use, viral load, and antiretroviral therapy. For every one-unit decline in IGF-1 z-score, sCD163 and sCD14 increased by 14% (95% CI, 0.23-29%) and 29% (95% CI, 1.4-63%), respectively.

CONCLUSION

Low IGF-1 was robustly associated with high sCD163 and sCD14 in HIV. Prospective studies are needed to investigate augmentation of IGF-1 as a novel strategy to reduce monocyte/macrophage activation in this population.

Transplant of insulin-like growth factor-1 expressing bone marrow stem cells improves functional regeneration of injured rat uterus by NF-κB pathway

To investigate the potential beneficial effect of insulin-like growth factor-1 (IGF-1) in BMSC transplantation therapy of uterus injury and the underlying molecular mechanisms, rat BMSCs were isolated and cultured. The relative expressions of IGF-1 and IL-10 were determined by RT-PCR and immunoblotting. The secretory IL-10 and released E2 were measured using ELISA kits. The relative vWF and α-SMA expressions were determined by immunohistochemistry. The direct binding of NF-κB subunit p50 with IL-10 promoter was analysed by chromatin immunoprecipitation assay. The regulation of IL-10 expression by p50 was interrogated by luciferase reporter assay. Our data demonstrated that IGF-1 expression in BMSCs induced IL-10 expression and secretion, which was further enhanced by E2-PLGA. IGF-1 overexpression improved BMSCs transplantation therapy in rat uterus injury. We further demonstrated that both inhibition and knockdown of p50 abolished IGF-1-induced expression and secretion of IL-10 in BMSCs, which consequently compromised the IGF-1 conferred therapeutic benefits against uterus injury. Furthermore, we elucidated that p50 regulated IL-10 expression via direct association with its promoter. Our data suggested that transplantation of IGF-1 overexpressing BMSCs improved functional regeneration of injured uterus by inducing IL-10 expression and secretion via activation of NF-κB signalling.

miR-483-3p regulates acute myocardial infarction by transcriptionally repressing insulin growth factor 1 expression

The aim of the present study was to evaluate the functional association between the expression of miR‑483‑3p and acute myocardial infarction (AMI) in patients and in vitro. H9c2 cells were incubated in a vacuum with 5% CO2, 5% H2 and 90% N2 for 2 h, which generated the AMI model in vitro. Reverse transcription‑quantitative polymerase chain reaction was used to measure miR‑483‑3p expression, and flow cytometry analysis and ELISA analysis were used to analyze apoptosis rate via caspase‑3 and caspase‑9 activity kits. B‑cell lymphoma 2 (Bcl‑2)/Bcl‑2‑associated X protein (Bax) and transcriptionally suppressed the protein expression of insulin growth factor 1 (IGF‑1) were analyze using western blot analysis. The results demonstrated that the expression of miR‑483‑3p in patients with AMI was increased when compared with the control group. In the in vitro model, the overexpression of miR‑483‑3p promoted apoptosis, increased caspase‑3 and caspase‑9 activity levels, induced the protein expression of Bcl‑2/Bax and IGF‑1. Picropodophyllotoxin, an IGF‑1 inhibitor, was administered to cells following the overexpression of miR‑483‑3p. Administration of picropodophyllotoxin suppressed IGF‑1 protein expression, promoted apoptosis, increased caspase‑3 and caspase‑9 activity levels, and induced the protein expression of Bax/Bcl‑2. The results of the present study revealed that miR‑483‑3p may regulate AMI via the IGF‑1 signaling pathway and may support the restoration of functional performance following AMI.

Relation of the IGF/IGF1R system to autophagy in colitis and colorectal cancer

Metabolic syndrome (MetS), as a chronic inflammatory disorder has a potential role in the development of inflammatory and cancerous complications of the colonic tissue. The interaction of DNA damage and inflammation is affected by the insulin-like growth factor 1 receptor (IGF1R) signaling pathway. The IGF1R pathway has been reported to regulate autophagy, as well, but sometimes through a bidirectional context. Targeting the IGF1R-autophagy crosstalk could represent a promising strategy for the development of new antiinflammatory and anticancer therapies, and may help for subjects suffering from MetS who are at increased risk of colorectal cancer. However, therapeutic responses to targeted therapies are often shortlived, since a signaling crosstalk of IGF1R with other receptor tyrosine kinases or autophagy exists, leading to acquired cellular resistance to therapy. From a pharmacological point of view, it is attractive to speculate that synergistic benefits could be achieved by inhibition of one of the key effectors of the IGF1R pathway, in parallel with the pharmacological stimulation of the autophagy machinery, but cautiousness is also required, because pharmacologic IGF1R modulation can initiate additional, sometimes unfavorable biologic effects.

Suppression of Basic Fibroblast Growth Factor Expression by Antisense Oligonucleotides Inhibits Neural Stem Cell Proliferation and Differentiation in Rat models With Focal Cerebral Infarction

This study is designed to investigate the role of basic fibroblast growth factor (bFGF) antisense oligonucleotide (ASODN) on the proliferation and differentiation of neural stem cells (NSCs) in rat models with focal cerebral infarction (CI). Seventy-five Sprague-Dawlay (SD) rats were randomly divided into the control, sham, middle cerebral artery occlusion (MCAO), MCAO + nonsense oligonucleotide (NODN), and MCAO + ASODN groups. Proliferation and differentiation of NSCs were detected by bromodeoxyuridine (BrdU) and immunofluorescence staining, respectively. ELISA was performed to detect the expressions of endogenous factors that include insulin-like growth factor 1 (IGF-1), glial cell line derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), transforming growth factor-α1 (TGF-α1), bFGF, and nerve growth factor (NGF). Results show significant neurological deficits and focal CI in the MCAO and MCAO + NODN groups. An obvious increase of NSC proliferation, reactive proliferation of astrocytes in CI areas, differentiation of newly proliferated NSCs into mature neuronal cells, and expressions of endogenous growth factors exhibited in the MCAO, MCAO + NODN and MCAO + ASODN groups. Compared to the MCAO and MACO + NODN groups, the MCAO + ASODN group showed a significant decrease NSC proliferation and differentiation in CI areas as well as decrease expressions of endogenous growth factors. These findings may offer insight to help us understand more as to how bFGF ASODN can effectively suppress the proliferation and differentiation of NSCs. These findings are expected to help contribute to research for new targets in the treatment of focal CI. J. Cell. Biochem. 118: 3875-3882, 2017. © 2017 Wiley Periodicals, Inc.

Skeletal muscle inflammation and atrophy in heart failure

Heart failure represents a systemic disease with profound effects on multiple peripheral tissues including skeletal muscle. Within the context of heart failure, perturbations in skeletal muscle physiology, structure, and function strongly contribute to exercise intolerance and the morbidity of this devastating disease. There is growing evidence that chronic heart failure imparts specific pathological changes within skeletal muscle beds resulting in muscle dysfunction and tissue atrophy. Mechanistically, systemic and local inflammatory responses drive critical aspects of this pathology. In this review, we will discuss pathological mechanisms that drive skeletal muscle inflammation and highlight emerging roles for distinct innate immune subsets that reside within damage muscle tissue focusing on the recently described embryonic and monocyte-derived macrophage lineages. Within this context, we will discuss how immune mechanisms can be differentially targeted to stimulate skeletal muscle inflammation, catabolism, fiber atrophy, and regeneration.

miR-301a promotes intestinal mucosal inflammation through induction of IL-17A and TNF-α in IBD

OBJECTIVE

MicroRNA (miR)-301a is known to be involved in the tumourigenesis and pathogenesis of several autoimmune diseases, but it remains unclear whether miR-301a is associated with the pathogenesis of IBD.

METHODS

miR-301a expression was assessed in peripheral blood mononuclear cells (PBMC) and inflamed mucosa of patients with IBD by quantitative real-time-PCR. Peripheral blood CD4+ T cells were transduced with lentivirus-encoding pre-miR-301a (LV-miR-301a) or a reverse complementary sequence of miR-301a (LV-anti-miR-301a), and their differentiation and activation were investigated in vitro. Antisense miR-301a was administered into mice during trinitrobenzene sulphonic acid (TNBS)-induced colitis to determine its role in colitis.

RESULTS

miR-301a expression was significantly upregulated in PBMC and inflamed mucosa of patients with IBD compared with healthy controls. Stimulation with tumour necrosis factor-α (TNF-α) significantly enhanced miR-301a expression in IBD CD4+ T cells, which was markedly reversed by anti-TNF-α mAb (Infliximab) treatment. Transduction of LV-miR-301a into CD4+ T cells from patients with IBD promoted the Th17 cell differentiation and TNF-α production compared with the cells with expression of LV-anti-miR-301a. SNIP1 as a functional target of miR-301a was reduced in miR-301a expression but increased in LV-anti-miR-301a expression. Knockdown of SNIP1 could enhance Th17 cell differentiation. Furthermore, intracolonical administration of antisense miR-301a in TNBS-induced mouse colitis model significantly decreased numbers of interleukin (IL)-17A+ cells and amounts of pro-inflammatory cytokines (eg, IL-17A, TNF-α) in inflamed colon.

CONCLUSIONS

Our data reveal a novel mechanism in which the elevated miR-301a in PBMC and inflamed mucosa of IBD promotes Th17 cell differentiation through downregulation of SNIP1. Blockade of miR-301a in vivo may serve as a novel therapeutic approach in the treatment of IBD.

Role of IGF1R(+) MSCs in modulating neuroplasticity via CXCR4 cross-interaction

To guide the use of human mesenchymal stem cells (MSCs) toward clinical applications, identifying pluripotent-like-markers for selecting MSCs that retain potent self-renewal-ability should be addressed. Here, an insulin-like growth factor 1 receptor (IGF1R)–expressing sub-population in human dental pulp MSCs (hDSCs), displayed multipotent properties. IGF1R expression could be maintained in hDSCs when they were cultured in 2% human cord blood serum (hUCS) in contrast to that in 10% fetal calf serum (FCS). Cytokine array showed that hUCS contained higher amount of several growth factors compared to FCS, including IGF-1 and platelet-derived growth factor (PDGF-BB). These cytokines modulates the signaling events in the hDSCs and potentially enhances engraftment upon transplantation. Specifically, a bidirectional cross-talk between IGF1R/IGF1 and CXCR4/SDF-1α signaling pathways in hDSCs, as revealed by interaction of the two receptors and synergistic activation of both signaling pathways. In rat stroke model, animals receiving IGF1R⁺ hDSCs transplantation, interaction between IGF1R and CXCR4 was demonstrated to promote neuroplasticity, therefore improving neurological function through increasing glucose metabolic activity, enhancing angiogenesis and anti-inflammatiory effects. Therefore, PDGF in hUCS-culture system contributed to the maintenance of the expression of IGF1R in hDSCs. Furthermore, implantation of IGF1R⁺ hDSCs exerted enhanced neuroplasticity via integrating inputs from both CXCR4 and IGF1R signaling pathways.

Mycobacterium leprae-induced Insulin-like Growth Factor I attenuates antimicrobial mechanisms, promoting bacterial survival in macrophages

Mycobacterium leprae (ML), the etiologic agent of leprosy, can subvert macrophage antimicrobial activity by mechanisms that remain only partially understood. In the present study, the participation of hormone insulin-like growth factor I (IGF-I) in this phenomenum was investigated. Macrophages from the dermal lesions of the disseminated multibacillary lepromatous form (LL) of leprosy expressed higher levels of IGF-I than those from the self-limited paucibacillary tuberculoid form (BT). Higher levels of IGF-I secretion by ML-infected macrophages were confirmed in ex vivo and in vitro studies. Of note, the dampening of IGF-I signaling reverted the capacity of ML-infected human and murine macrophages to produce antimicrobial molecules and promoted bacterial killing. Moreover, IGF-I was shown to inhibit the JAK/STAT1-dependent signaling pathways triggered by both mycobacteria and IFN-γ most probably through its capacity to induce the suppressor of cytokine signaling-3 (SOCS3). Finally, these in vitro findings were corroborated by in vivo observations in which higher SOCS3 expression and lower phosphorylation of STAT1 levels were found in LL versus BT dermal lesions. Altogether, our data strongly suggest that IGF-I contributes to the maintenance of a functional program in infected macrophages that suits ML persistence in the host, reinforcing a key role for IGF-I in leprosy pathogenesis.

FTY720 (Gilenya) treatment prevents spontaneous autoimmune myocarditis and dilated cardiomyopathy in transgenic HLA-DQ8-BALB/c mice

Although dilated cardiomyopathy (DCM) is often caused by viral infections, it frequently involves autoimmune mechanisms associated with particular HLA-DR and DQ alleles. Our homozygous HLA-DQ8Ab(0) transgenic mice in the BALB/c background (HLA-DQ8(BALB/c)-Tg) developed early and progressive fatal heart failure from 4 to 5 weeks of age. Clinical signs of the disease included cyanotic eyes, tachycardia with dyspnea (from pale to cyanotic limbs), and terminal whole body edema. Sick mice had extremely dilated hearts, enlarged liver and spleen, and pleural/peritoneal effusion. Histology of the heart showed extensive heart muscle destruction with signs of fibrosis. The autoimmune nature of the disease was shown by high titers of antimyosin antibodies in the sera and IgG deposits in sick heart muscles, as well as focal neutrophil, T cell, and macrophage infiltration of the heart muscle. The sera of the sick mice showed a granular staining pattern on sections of healthy heart muscle. Quantitative analyses of DCM-specific gene expression studies revealed that sets of genes are involved in inflammation, hypoxia, and fibrosis. Treatment with FTY720 (Fingolimod/Gilenya) protected animals from the development of cardiomyopathy. HLA-DQ8(BALB/c)-Tg mice represent a spontaneous autoimmune myocarditis model that may provide a useful tool for studying the autoimmune mechanism of DCM and testing immunosuppressive drugs.

Expression of guanylate cyclase-C, guanylin, and uroguanylin is downregulated proportionally to the ulcerative colitis disease activity index

The transmembrane receptor guanylate cyclase-C (GC-C) signaling pathway has been implicated in several gastrointestinal disorders. Activation of GC-C via guanylin (Gn) and uroguanylin (Ugn) regulates intestinal fluid and electrolyte homeostasis. However, how it regulates the pathogenesis of inflammatory bowel disease (IBD) is still unclear. Here, we investigated the activation of GC-C signaling in ulcerative colitis (UC) of different clinical severities. A total of 60 UC patients and 20 normal controls were recruited. Evaluation of the UC disease activity index (DAI) was performed using a modified Mayo scoring system. The expression of GC-C, Gn and Ugn in the colonic mucosa was measured by quantitative real-time PCR and Western blot. We found that the UC patients had significantly lower expression of GC-C, Gn and Ugn than the controls. Furthermore, there were significant differences for GC-C, Gn and Ugn expression for the UC groups of Grade 1, 2 and 3, and their expression levels were reduced with increases in their DAI. Taken together, our results demonstrate that GC-C, Gn and Ugn are downregulated in UC, and this downregulation is more significant with aggravation of the clinical condition. Therefore, the GC-C signaling pathway may be implicated in the progression of UC.

Divalent metal-ion transporter 1 is decreased in intestinal epithelial cells and contributes to the anemia in inflammatory bowel disease

Divalent metal-ion transporter 1 (DMT1) has been found to play an important role in the iron metabolism and hemogenesis. However, little is known about the potential role of DMT1 in the pathogenesis of anemia from patients with inflammatory bowel disease (IBD). Herein, we investigated expression of DMT1 in the intestinal mucosa by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry, and found that DMT1 was significantly decreased in the inflamed mucosa of active IBD patients compared with that in those patients at remission stage and healthy controls. To further study the mechanism, we cultured HCT 116 cell line in vitro. Expression of DMT1 in HCT116 was demonstrated to be markedly decreased under stimulation with TNF for 24 and 48 h, while JNK inhibitor (JNK-IN-7) could significantly reverse the decrease. Interestingly, anti-TNF therapy successfully improved anemia in clinical responsive Crohn’s disease patients, and DMT1 was found to be markedly up-regulated in intestinal mucosa. Taken together, our studies demonstrate that decreased expression of DMT1 in intestinal mucosa leads to compromised absorption and transportation of iron and that blockade of TNF could rescue anemia and promote DMT1 expression in gut mucosa. This work provides a therapeutic approach in the management of anemia in IBD.

Regulatory immune cells in regulation of intestinal inflammatory response to microbiota

The intestinal lumen harbors nearly 100 trillion commensal bacteria that exert crucial function for health. An elaborate balance between immune responses and tolerance to intestinal microbiota is required to maintain intestinal homeostasis. This process depends on diverse regulatory mechanisms, including both innate and adaptive immunity. Dysregulation of the homeostasis between intestinal immune systems and microbiota has been shown to be associated with the development of inflammatory bowel diseases (IBD) in genetically susceptible populations. In this review, we discuss the recent progress reported in studies of distinct types of regulatory immune cells in the gut, including intestinal intraepithelial lymphocytes, Foxp3(+) regulatory T cells, regulatory B cells, alternatively activated macrophages, dendritic cells, and innate lymphoid cells, and how dysfunction of this immune regulatory system contributes to intestinal diseases such as IBD. Moreover, we discuss the manipulation of these regulatory immune cells as a potential therapeutic method for management of intestinal inflammatory disorders.

Stress-caused anergy of leukocytes towards Staphylococcal enterotoxin B and exposure transcriptome signatures

Leucocytes from soldiers exposed to battlefield-like stress (RASP: Rangers Assessment and Selection Program) were exposed in vitro to Staphylococcal enterotoxin B (SEB). We assayed SEB-induced regulation of gene expression, both in the presence and absence of severe stress, to generate two sets of gene profiles. One set of transcripts and microRNAs were specific to post-RASP SEB exposure, and another set were signatures of SEB exposure common to both the pre- and post-RASP leucocytes. Pathways and upstream regulatory analyses indicated that the post-RASP SEB-signature transcripts were manifestation of the anergic state of post-RASP leucocytes. These were further verified using expression-based predictions of cellular processes and literature searches. Specificity of the second set of transcripts to SEB exposure was verified using machine-learning algorithms on our and four other (Gene Expression Omnibus) data sets. Cell adhesion, coagulation, hypoxia and vascular endothelial growth factor-mediated vascular leakage were SEB-specific pathways even under the background of severe stress. Hsa-miR-155-3p was the top SEB exposure predictor in our data set, and C-X-C motif chemokine ligand 9 was SEB specific in all the analyzed data sets. The SEB-signature transcripts (which also showed distinct expression signatures from Yersinia pestis and dengue virus) may serve as potential biomarkers of SEB exposure even under the background of stress.

IGF1 stimulates crypt expansion via differential activation of 2 intestinal stem cell populations

Insulin-like growth factor 1 (IGF1) has potent trophic effects on normal or injured intestinal epithelium, but specific effects on intestinal stem cells (ISCs) are undefined. We used Sox9-enhanced green fluorescent protein (EGFP) reporter mice that permit analyses of both actively cycling ISCs (Sox9-EGFP(Low)) and reserve/facultative ISCs (Sox9-EGFP(High)) to study IGF1 action on ISCs in normal intestine or during crypt regeneration after high-dose radiation-induced injury. We hypothesized that IGF1 differentially regulates proliferation and gene expression in actively cycling and reserve/facultative ISCs. IGF1 was delivered for 5 days using subcutaneously implanted mini-pumps in uninjured mice or after 14 Gy abdominal radiation. ISC numbers, proliferation, and transcriptome were assessed. IGF1 increased epithelial growth in nonirradiated mice and enhanced crypt regeneration after radiation. In uninjured and regenerating intestines, IGF1 increased total numbers of Sox9-EGFP(Low) ISCs and percentage of these cells in M-phase. IGF1 increased percentages of Sox9-EGFP(High) ISCs in S-phase but did not expand this population. Microarray revealed that IGF1 activated distinct gene expression signatures in the 2 Sox9-EGFP ISC populations. In vitro IGF1 enhanced enteroid formation by Sox9-EGFP(High) facultative ISCs but not Sox9-EGFP(Low) actively cycling ISCs. Our data provide new evidence that IGF1 activates 2 ISC populations via distinct regulatory pathways to promote growth of normal intestinal epithelium and crypt regeneration after irradiation.