Nuclear factor-κB1 and MicroRNA-146a polymorphisms and risk of acute graft versus host disease post allogeneic stem cell transplantation

Acute graft-versus-host disease (aGVHD) is a severe inflammatory complication of haematopoeitic stem cell transplantation. The nuclear factor- Kappa Beta (NF-κB) signaling pathway regulates T cell activation. The NF-κB controls the expression of microRNA-146a (miR-146a) that in turn regulates NF-κB activation through a negative feedback loop. We aim to analyze the association between NF-κB1 encoding p50 (rs28362491, −94 in.ertion/deletion ATTG) and miR-146a (rs2910164, G > C) polymorphisms and risk of aGVHD. Genotyping was performed for 135 HLA-matched donors using polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP).The incidence of aGVHD grades II-IV was 24/135 (17.8 %). NF-κB1 genotype and cytomegalovirus infection were significantly associated with risk of aGVHD II-IV (p = 0.022, HR = 3.17, 95 % CI:1.18-8.51 and p = 0.048, HR = 2.56, 95 % CI:1.01–6.52, respectively). In multivariate analysis, NF-κB1homozygous deletion/deletion genotype was the only independent risk factor associated with aGVHD II-IV (p = 0.013, HR = 3.50, 95 % CI:1.30–9.44). No significant association could be observed between miR-146a polymorphism and aGVHD. Combined NF-κB1 and miR146a genotype analysis warrants investigation in a larger cohort. Our preliminary data do not support the association between miR146a and aGVHD, but suggest an association between NF-κB1 and risk of aGVHD that may pave the way for the development of a novel targeted therapy if proved in a larger cohort.     

CXCR4 positive bone mesenchymal stem cells migrate to human endothelial cell stimulated by ox-LDL via SDF-1α/CXCR4 signaling axis

Background

Bone mesenchymal stem cells (BMSCs) are attractive candidates for cell based therapies to cardiovascular disease such as infarction and atherosclerosis; however, the mechanisms responsible for stem cell chemotaxis and homing remain unknown. Chemokine stromal cell-derived factor 1 (SDF-1α) is involved in the process of atherogenesis. This study was aimed at investigating whether the SDF-1α of human umbilical vein endothelial cells (HUVECs) plays a role in migration of BM-derived CXCR4⁺(receptor for SDF-1α) stem cells.

Methods

HUVECs were cultured from human umbilical cords and was treated with ox-LDL. The mRNA and protein expression of SDF-1α was detected in HUVECs. CXCR4⁺BMSCs from bone marrow were isolated and were tested by migration and adhesion assays.

Results

It was found that ox-LDL induced HUVECs to increase the mRNA and protein expression of SDF-1α. Ox-LDL increased the migratory and adhesion response of CXCR4⁺BMSCs. When the neutralizing SDF-1α antibody abrogated the secreted SDF-1α, the migration and adhesion response of CXCR4⁺BMSCs markedly decreased.

Conclusions

Our data indicated that the endothelial cells (ECs) stimulated by ox-LDL could increase the BMSCs migratory response via SDF-1α/CXCR4 signaling axis. These findings provide a new paradigm for biological effects of ox-LDL and have implications for novel stem cell therapeutic strategies for atherosclerosis.     

α-Tocopherol induces hematopoietic stem/progenitor cell expansion and ERK1/2-mediated differentiation

Tocopherols promote or inhibit growth in different cell types. In the hematopoietic system, the radioprotective property of tocopherols is thought to act through the expansion of primitive hematopoietic cells. However, the mechanisms activated by tocopherols and which HPs are affected remain poorly understood. To better address these questions, mice were treated with α-tocopherol, and its effects were investigated in the BM microenvironment. α-Tocopherol induced increased proliferation in HSC/HP cells, leading to BM hyperplasia. In addition, differentiation to the granulocytic/monocytic lineage was enhanced by α-tocopherol treatment. α-Tocopherol treatment resulted in decreased basal phosphorylation of ERK1/2, PKC, and STAT-5 in HSC/HP cells. In contrast, α-tocopherol enhanced ERK1/2 activation in response to IL-3 stimulation in HSC/HP cells without altering the expression of IL-3Rs. Moreover, α-tocopherol-induced differentiation and ERK1/2 activation were abolished in mice pretreated with a MEK inhibitor (PD98059); however, pretreatment with PD98059 did not reduce the α-tocopherol-mediated increase in HSC/HP cells but instead, further enhanced their proliferation. Therefore, α-tocopherol induces expansion of HSC/HP cells by a nonidentified intracellular pathway and granulocytic/monocytic differentiation through ERK1/2 activation.     

Synergistic effects of SDF-1α chemokine and hyaluronic acid release from degradable hydrogels on directing bone marrow derived cell homing to the myocardium

Poor cell engraftment in the myocardium is a limiting factor towards the use of bone marrow derived cells (BMCs) to treat myocardial infarction (MI). In order to enhance the engraftment of circulating BMCs in the myocardium following MI, we have developed in situ forming hyaluronic acid (HA) hydrogels with degradable crosslinks to sustain the release of recombinant stromal cell-derived factor-1 alpha (rSDF-1α) and HA to the injured myocardium. Both rSDF-1α and the crosslinkable HA macromer stimulate BMC chemotaxis up to 4-fold in?vitro through CXCR4 and CD44 receptor signaling, respectively. Moreover, the HA macromer binds rSDF-1α with a dissociation constant of 36?±?5?μM through electrostatic interaction. When formed into hydrogels via photoinitiated crosslinking, release of encapsulated rSDF-1α and crosslinked HA was sustained for over 7 days, and these molecules significantly increased BMC chemotaxis in?vitro. When applied to the heart following experimental MI in mice, the HA gel containing rSDF-1α significantly increased the number of systemically infused BMCs in the heart by ～8.5 fold after 7 days, likely through both systemic and local effects of released molecules. We conclude that sustained release of rSDF-1α and HA from our engineered HA hydrogels enhances BMC homing to the remodeling myocardium better than delivery of rSDF-1α alone.     

Levels and patterns of expression of hypoxia-inducible factor-1α, vascular endothelial growth factor, glucose transporter-1 and CD105 in adenoid cystic carcinomas with high-grade transformation

Costa A F, Tasso M G, Mariano F V, Soares A B, Chone C T, Crespo A N, Fresno M F, Llorente J L, Suárez C, de Araújo V C, Hermsen M & Altemani A
(2012) Histopathology  60, 816–837 Levels and patterns of expression of hypoxia‐inducible factor‐1α, vascular endothelial growth factor, glucose transporter‐1 and CD105 in adenoid cystic carcinomas with high‐grade transformation Aims: To compare the expression of proteins regulated by hypoxia between adenoid cystic carcinoma (ACC) with and without high‐grade transformation (HGT). Methods and results: In eight ACC–HGT and 18 ACC without HGT, expression of hypoxia‐inducible factor‐1 (HIF‐1α), vascular endothelial growth factor (VEGF), glucose transporter‐1 (GLUT‐1) and microvascular density (MVD) by CD105 (a hypoxia‐inducible protein expressed in angiogenic endothelial cells) was determined. Expression levels of HIF‐1α and VEGF as well as CD105‐MVD did not differ significantly between: (i) transformed and conventional areas (TA and CA, respectively) of ACC–HGT, (ii) CA and ordinary ACC. HIF‐1α was detected in 100% of cases and presented a diffuse expression pattern. No significant association was found between levels of HIF‐1α expression and tumour size, metastasis and recurrence. GLUT‐1 showed a prostromal expression pattern and was observed exclusively in TA (three of six cases) and in only three of 14 ACC. Conclusions: Both the absence of significant alterations in levels of expression of HIF‐1α, VEGF and CD105 and the patterns of expression of HIF‐1α and GLUT‐1 suggest that hypoxia may not play a key role in the process of high‐grade transformation of ACC. Although HIF‐1α expression is a common finding in ACC, it cannot be used as a marker of tumour aggressiveness.     

Angiogenesis and expression of vascular endothelial growth factor, tumour necrosis factor-α and hypoxia inducible factor-1α in canine renal cell carcinoma

The aim of the present study was to determine the distribution and characteristics of microvessels in various histological types of canine renal cell carcinoma (RCC). The study compared microvessel density (MVD) and distribution of blood vessels according to histological type and evaluated the presence of angiogenesis-related proteins. Nine archival samples of canine RCC were studied. MVD was calculated as the mean number of blood vessels per mm(2). The diameter of blood vessels was calculated by determining either the length of the long axis of blood vessels (diameter(max)) or the mean distance from the centre of each blood vessel to the tunica adventia (diameter(mean)). A significant difference in MVD was evident between RCCs and normal kidneys (46.6 ± 28.0 versus 8.4 ± 2.2 microvessels/mm(2)). Diameter(max) in canine RCCs (34.1 ± 14.7 μm) was also significantly different from normal canine kidney (23.2 ± 3.4 μm). Vascular endothelial growth factor (VEGF) was expressed by tumour cells and vascular endothelial cells and tumour necrosis factor (TNF)-α expression was observed in vascular endothelial cells in both neoplastic and normal kidney. Although VEGF is involved in angiogenesis and correlates with tumour stage of development, no correlation was found between VEGF expression and MVD. Tumour-associated macrophages expressing TNF-α and hypoxia inducible factor 1α were identified in peritumoural tissue and may play an important role in angiogenesis.     

Hypoxia,hypoxia-inducible factor-1α and vascular endothelial growth factor in a murine model of Schistosoma mansoni infection

Schistosomiasis mansoni is a chronic parasitic disease where much of the symptomatology is attributed to granuloma formation, an immunopathological reaction against Schistosoma eggs. To more clearly understand the immunopathology of schistosomiasis, the tissue microenvironment generated by S. mansoni infected mice was investigated. Using the hypoxia marker pimonidazole, we provide immunohistochemical evidence that hypoxia occurred in inflammatory cells infiltrated around the eggs and cells surrounding granulomas in the liver, intestine, spleen and lungs of infected mice. Hypoxia-inducible factor-1α (HIF-1α) was mainly expressed in inflammatory cells surrounding the eggs and in hepatocytes surrounding cellular and fibrocellular granulomas in infected mouse liver. HIF-1α expression was also verified in granulomas in the other tissues tested (intestine, spleen and lungs). Vascular endothelial growth factor (VEGF) expression was observed in the extracellular space surrounding inflammatory cells in liver granuloma. The VEGF expression pattern verified in infected mouse liver was very similar to that observed in the other tissues tested. A strong positive correlation occurred between pimonidazole binding and HIF-1α and VEGF expression in the tissues tested, except for lung. This work is the first evidence that infection by a helminth parasite, S. mansoni, produces a hypoxic tissue microenvironment and induces HIF-1α and VEGF expression.     

PPARα ligands cause lymphocyte depletion and cell cycle block and this is associated with augmented TRB3 and reduced Cyclin B1 expression

PPARα ligands are medications used clinically to prevent cardiovascular events, however studies have shown that these agents are also anti-inflammatory. Our previous studies have shown that PPARα ligands induce lymphocyte depletion. PPARα ligands also potently upregulate TRB3, a protein that has been associated with cell cycle arrest. Therefore the following studies were undertaken to determine the mechanisms associated with lymphocyte depletion. Our studies demonstrate that WY14,643, a PPARα ligand, decreases the amount of lymphocytes recovered after stimulation and reduces cellular divisions. Cells treated with WY14,643 also accumulate in the G2/S phase of the cell cycle. TRB3 has been shown to inhibit the phosphorylation of AKT/Protein Kinase B, and reduced activation of AKT has been associated with decreased cellular divisions and survival. However in lymphocytes, TRB3 did not reduce the phosphorylation of AKT, and WY14,643 treatment was associated with enhanced activation of AKT. Drosophila tribbles (TRB3 homolog) causes G2 arrest by decreasing the expression of a Cdc25c homolog. Lymphocytes stimulated and treated with WY14,643 have reduced expression of Cdc25c, however this is not associated with enhanced expression of phosphorylated-Cdc2 which induces G2 arrest. Instead we observed that WY14,643 consistently reduces the protein and mRNA expression of Cyclin B1. Moreover, TRB3 inhibits activation of a Cyclin B1 promoter construct. In summary, we propose that PPARα ligands may reduce cellular number by augmenting TRB3 expression, which in turn induces cell cycle arrest by reducing the expression of Cyclin B1. Reduced cellular divisions and cell cycle arrest may be responsible for some of the immunomodulatory effects of these agents that have been consistently observed in human trials.     

Differentiated thyroid carcinomas with vascular invasion: a comparative study of follicular,Hürthle cell and papillary thyroid carcinoma

AIM: Non-medullary thyroid carcinomas arise from follicular cells. The purpose of this study is to correlate clinical and pathological properties of these tumours with the rate of distant metastasis from a series of thyroid tumours excised at one institution. METHODS: A total of 311 non-medullary thyroid tumours were identified and divided into: 29 follicular carcinoma (FC), 12 Hürthle cell carcinoma (HC), 13 Hürthle cell papillary thyroid carcinoma (HPTC) with vascular invasion (VI), 32 papillary thyroid carcinoma (PTC) with VI and 225 PTC without VI. The mean follow-up was 6.5 years with a range of 1-17 years. The tumours were histologically subdivided into minimal or wide invasion for FC and HC and focal or extensive invasion for PTC and HPTC, and stratified according to status of VI. RESULTS: The rate of distant metastasis was similar for FC, malignant Hürthle cell tumours and PTC with VI, and increased with extent of invasion. VI was seen in 12% of all PTC and 0% of HPTC in this study. PTC without VI were associated with a much lower potential of distant metastasis, were smaller in size and occurred in patients of younger age than PTC with VI. In addition, there was a tendency for increased potential for distant metastases with increased tumour size and patient age for all groups of tumours in the study. Patient age and tumour size appeared to play a smaller role than that of VI in predicting distant metastasis. CONCLUSIONS: Our study suggests that the rate of distant metastasis relates to VI, patient age and tumour size, regardless of Hürthle cell, FC or PTC differentiation. PTC of large size, and in patients older than 45 years, have a high propensity for vascular invasion.     

KF19514, a phosphodiesterase 4 and 1 inhibitor,inhibits TNF-α-induced GM-CSF production by a human bronchial epithelial cell line via inhibition of PDE4

Objective and design: Bronchial epithelium plays an important role in the regulation of inflammatory reactions in the airways. We investigated the effect of KF19514, a phosphodiesterase (PDE) 4 and 1 inhibitor, on granulocyte-macrophage colony-stimulating factor (GM-CSF) production by a human bronchial epithelial cell line, BEAS-2B.Methods: BEAS-2B cells were stimulated with the tumor necrosis factor- (TNF-) and various concentrations of test agents for 48 h. Supernatants were assayed for GM-CSF by using an enzyme-linked immunosorbent assay (ELISA). In addition, intracellular cyclic AMP (cAMP) levels were measured in the presence of various agents.Results: KF19514 significantly inhibited the release of GM-CSF by BEAS-2B cells in a concentration-dependent manner. The other PDE4 inhibitors and cAMP-elevating agents also inhibited the GM-CSF production. In the BEAS-2B cells, KF19514 and PDE4 inhibitors concentration-dependently increased intracellular cAMP levels. The inhibitory effect of KF19514 on the GM-CSF production was significantly reduced by a cAMP-dependent protein kinase A (PKA) inhibitor, H89. On the other hand, other PDE isozyme inhibitors did not inhibit the GM-CSF production by BEAS-2B cells, and did not elevate the intracellular cAMP levels.Conclusions: These results indicate that KF19514 and PDE4 inhibitors reduce TNF--induced GM-CSF production of BEAS-2B cells via a cAMP-dependent pathway. PDE4 may be a possible target for the regulation of cytokine production in epithelial cells.Received 24 February 2003; returned for revision 27 March 2003; accepted by M. J. Parnham 5 September 2003     

The effect of stromal cell-derived factor-1α/heparin coating of biodegradable vascular grafts on the recruitment of both endothelial and smooth muscle progenitor cells for accelerated regeneration

Small-diameter synthetic vascular grafts have high failure rate and tissue-engineered blood vessels are limited by the scalability. Here we engineered bioactive materials for in situ vascular tissue engineering, which recruits two types of endogenous progenitor cells for the regeneration of blood vessels. Heparin was conjugated to microfibrous vascular grafts to suppress thrombogenic responses, and stromal cell-derived factor-1α (SDF-1α) was immobilized onto heparin to recruit endogenous progenitor cells. Heparin-bound SDF-1α was more stable than adsorbed SDF-1α under both static and flow conditions. Microfibrous grafts were implanted in rats by anastomosis to test the functional performance. Heparin coating improved the short-term patency, and immobilized SDF-1α further improved the long-term patency. SDF-1α effectively recruited endothelial progenitor cells (EPCs) to the luminal surface of the grafts, which differentiated into endothelial cells (ECs) and accelerated endothelialization. More interestingly, SDF-1α increased the recruitment of smooth muscle progenitor cells (SMPCs) to the grafts, and SMPCs differentiated into smooth muscle cells (SMCs) in?vivo and in?vitro. Consistently, SDF-1α-immobilized grafts had significantly higher elastic modulus. This work demonstrates the feasibility of simultaneously recruiting progenitor cells of ECs and SMCs for in situ blood vessel regeneration. This in situ tissue engineering approach will have broad applications in regenerative medicine.     

Repairing critical-sized calvarial defects with BMSCs modified by a constitutively active form of hypoxia-inducible factor-1α and a phosphate cement scaffold

Tissue engineering combined with gene therapy represents a promising approach for bone regeneration. The Hypoxia-inducible factor-1α (HIF-1α) gene is a pivotal regulator of vascular reactivity and angiogenesis. Our recent study has showed that HIF-1α could promote osteogenesis of bone mesenchymal stem cells (BMSCs) using a gene point mutant technique. To optimize the function of HIF-1α on inducing stem cells, another constitutively active form of HIF-1α (CA5) was constructed with truncation mutant method and its therapeutic potential on critical-sized bone defects was evaluated with calcium-magnesium phosphate cement (CMPC) scaffold in a rat model. BMSCs were treated with Lenti (lentivirus) -CA5, Lenti-WT (wild-type HIF-1α), and Lenti-LacZ. These genetically modified BMSCs were then combined with CMPC scaffolds to repair critical-sized calvarial defects in rats. The results showed that the overexpression of HIF-1α obviously enhanced the mRNA and protein expression of osteogenic markers in?vitro and robust new bone formation with the higher local bone mineral density (BMD) was found in?vivo in the CA5 and WT groups. Furthermore, CA5 showed significantly greater stability and osteogenic activity in BMSCs compared with WT. These data suggest that BMSCs transduced with truncation mutanted HIF-1α gene can promote the overexpression of osteogenic markers. CMPC could serve as a potential substrate for HIF-1α gene modified tissue engineered bone to repair critical sized bony defects.