Expression of glucocorticoid receptors in mononuclear cells in nephrotic syndrome

Assessment of the Link of ABCB1 and NR3C1 gene polymorphisms with the prednisolone resistance in pediatric nephrotic syndrome patients of Bangladesh: A genotype and haplotype approach

Introduction

Nephrotic syndrome is a common pediatric kidney disease. Investigations on several genetic polymorphisms revealed an inconsistent influence on the resistance of patients to steroids.

Objectives

This study aimed to identify the association of ABCB1 (1236C > T, 2677G > T, 3435C > T), NR3C1 (rs10482634, rs6877893), and CYP3A5 (CYP3A5*3) gene polymorphism as well as sociodemographic and clinicopathological parameters with the risk of developing prednisolone resistance in pediatric patients with nephrotic syndrome.

Methods

A case-control analysis was performed on 180 nephrotic syndrome patients. Among them, 30 patients were classified as prednisolone resistant group, and 150 were classified as prednisolone sensitive group. Genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

Results

No significant association of 1236C > T polymorphism with the risk of prednisolone resistance (p > 0.05) was found. The GT heterozygous of 2677G > T was found to be significantly associated with the development of prednisolone resistance (OR = 3.9, p = 0.034). In the case of 3435C > T, a statistically significant association was observed in TC heterozygous and TT mutant homozygous genotypes (OR = 0.38, p = 0.047; OR = 3.06, p = 0.038, respectively) with prednisolone resistance. For rs10482634 polymorphism, the AG heterozygous and AG+GG genotypes were significantly linked with prednisolone resistance (OR = 2.40, p = 0.033; OR = 2.36, p = 0.034, respectively). We found no association with the risk of prednisolone resistance with rs6877893 and CYP3A5*3 polymorphism (p > 0.05). CTC and TGT haplotypes of ABCB1 and GA haplotype of NR3C1 were also associated with the increased risk of pediatric prednisolone resistance (OR = 4.47, p = 0.0003; OR = 2.71, p = 0.03; and OR = 4.22, p = 0.022, consecutively). We also observed the correlation of different sociodemographic and clinicopathological factors with prednisolone resistance in pediatric nephrotic syndrome.

Conclusion

Our findings showed a significant association of ABCB1 and NR3C1 gene polymorphisms with prednisolone resistant pediatric nephrotic syndrome.

Glomerular Glucocorticoid Receptors Expression and Clinicopathological Types of Childhood Nephrotic Syndrome

Glucocorticoids are primary therapy of idiopathic nephrotic syndrome (INS). However, not all children respond to steroid therapy. We assessed glomerular glucocorticoid receptor expression in fifty-one children with INS and its relation to response to steroid therapy and to histopathological type. Clinical, laboratory and glomerular expression of glucocorticoid receptors were compared between groups with different steroid response. Glomerular glucocorticoid expression was slightly higher in controls than in minimal change early responders, which in turn was significantly higher than in minimal change late responders. There was significantly lower glomerular glucocorticoid receptor expression in steroid-resistance compared to early responders, late responders and controls. Glomerular glucocorticoid expression was significantly higher in all minimal change disease (MCD) compared to focal segmental glomerulosclerosis. In INS, response to glucocorticoid is dependent on glomerular expression of receptors and peripheral expression. Evaluation of glomerular glucocorticoid receptor expression at time of diagnosis of NS can predict response to steroid therapy.

Low expression of glucocorticoid receptors in children with steroid-resistant nephrotic syndrome

BACKGROUND

About 10-20 % of children with idiopathic nephrotic syndrome (NS) are steroid-resistant (SR). Low expression of glucocorticoid receptors (GRs) has been associated with poor response to steroids in a variety of autoimmune diseases. This study was done to assess the expression of cytoplasmic GRs for CD3 and CD14 in children with NS.

METHODS

Expression of cytoplasmic GRs in lymphocytes (CD3(+)/GR) and monocytes (CD14(+)/GR) in the peripheral blood were assessed in 51 children with NS before the start of therapy by flow cytometry. Patients were divided into two groups: 30 children who were steroid-sensitive (SSNS) and 21 children who had initial steroid resistance (SRNS). Twenty age- and sex-matched healthy children served as controls.

RESULTS

Expression of CD3(+)/GR was significantly lower in SRNS in comparison to SSNS patients and controls (p < 0.0001). Similarly, expression of CD14(+)/GR was significantly lower in SRNS in comparison to SSNS patients (p < 0.0001) and controls (p = 0.002). CD3(+)/GR and CD14(+)/GR expression were not significantly different in SSNS patients compared with controls (p = 0.06 and 0.07 respectively).

CONCLUSIONS

Patients with initial SRNS showed decreased GR expression in peripheral blood mononuclear cells (PBMC) before starting therapy, and this low expression may be one of the pathophysiological mechanisms of steroid resistance in these children.

Flow cytometry analysis of glucocorticoid receptor expression and binding in steroid-sensitive and steroid-resistant patients with systemic lupus erythematosus

Introduction

Glucocorticoid (GC) therapy is the main treatment for systemic lupus erythematosus (SLE). However, some patients are resistant to these agents. Abnormalities of glucocorticoid receptor (GR) seem to be related to steroid resistance. This study evaluated GRs in T lymphocytes and monocytes of SLE patients by flow cytometry (FCM) using a monoclonal antibody (mAb) and FITC-Dex probes.

Methods

Thirty-five patients with SLE before treatment and 27 age- and sex-matched normal controls were studied. Disease activity scores were determined before and after treatment and used to divide the patients into steroid-resistant (SR) and steroid-sensitive (SS) groups. GRs in T lymphocytes (CD3⁺) and monocytes (CD14⁺) were examined by FCM with GR-mAb and FITC-Dex probes before treatment. Peripheral blood mononuclear cells (PBMCs) were isolated for in vitro GCs sensitivity assays. The validity of FCM analysis of intracellular staining for GR with GR-mAb and FITC-Dex probes was evaluated through comparison with western blot and radioligand binding assay (RLBA) in U937 and K562 cells in vitro. One-way ANOVA, student's t test, linear regression and spearman correlation were performed.

Results

A significant decrease in GR binding and the expression in K562 and U937 cells with 10^-6 M dexamethasone (Dex) was found compared with those without Dex. In addition, a positive correlation was found between FCM and RLBA as well as FCM and Western blot. The expression and binding of both CD3/GR and CD14/GR in SR patients with SLE, detected by FCM, were all lower than those in SS patients with SLE, whereas there was no significant difference in SS patients and controls. In vitro corticosteroid sensitivity assay indicated that PHA-stimulated tumour necrosis factor-α (TNF-α), IL-12 and interferon-γ (IFN-γ) secretion was significantly inhibited by 10^-6 M Dexamethasone in all controls and SS patients, compared with that in SR group, which confirms patient classification as SR and SS by disease activity index (SLEDAI) score.

Conclusions

Abnormalities of expression and binding of the GR may be involved in tissue resistance to steroids in SLE patients. Determination of GR expression and binding by FCM may be useful in predicting the response to steroid treatment of SLE patients.

Trial registration

Clinical trial registration number NCT00600652.

A novel quantitative flow cytometric method for measuring glucocorticoid receptor (GR) in cell lines: correlation with the biochemical determination of GR

Currently, a time consuming biochemical method is used for GR quantification. Here we compare the biochemical approach with a newly developed flow cytometric method of measuring GR in cell lines, which is less time consuming and does not requires the use of radioactive materials. The biochemical assay is easy to apply but the cells need to be grown in media free of endogenous glucocorticoids, in order to prevent them from interfering with radiolabelled hormone binding to the receptor. The presence of endogenous GR ligands is known to reduce receptor levels and to often produce false negative results. The immunofluorescent method is free of such limitations, as it depends entirely on detecting the receptor using a highly specific monoclonal antibody. Additionally, the biochemical assay cannot measure heterogeneity in individual cells, in contrast the flow cytometric one enables the enumeration of the receptor on a per cell basis, allowing exact description of differences in receptor levels amongst intact cells. Our results demonstrate that the flow cytometric method is of similar accuracy but of higher precision compared to the biochemical one. Also, the data we obtained using the immunofluorescent method correlated well with the biochemical one (R(2)=0.9712). In conclusion, flow cytometric method requires small cell numbers, is more accurate and lesser time consuming than the biochemical one. Thus, it could be useful for the quantification of GR in lymphocyte subpopulations, in lymphoproliferative disorders and in tumor cells from cancer patients, in order to design more efficient clinical treatment protocols.

Expression of P-glycoprotein in lymphocytes of children with nephrotic syndrome treated with glucocorticoids

INTRODUCTION

Glucocorticoids are still the mainstay of therapy for nephrotic syndrome (NS) in children. Poor response to glucocorticoids may relate, in part, to the overexpression of P-glycoprotein (P-gp). The aim of the present study was to determine the expression of P-gp in lymphocytes (CD3) in the peripheral blood of children with steroid-sensitive nephrotic syndrome in the dynamics of the disease. The study group (I) consisted of 18 children, median age 5.75 years, with steroid-sensitive nephrotic syndrome, in whom the examinations were carried out three times: (A) before treatment, during relapse; (B) after 3-4 weeks of prednisone treatment; (C) 2 months after finishing prednisone treatment. The control group (II) consisted of 18 healthy children of the same age. P-gp expression in CD3 lymphocytes of peripheral blood was measured using flow cytometry. During NS relapse and prior to glucocorticoid administration, the CD3/P-gp level was higher (median 3.20%, range 0.80-7.80%) when compared to healthy controls (1.10%, range 0.30- 2.20%) (p<0.01). During glucocorticoid treatment, CD3/P-gp increased significantly and was much higher than in the control group (p<0.01) and in the NS children before treatment (p<0.01). In remission, the P-gp expression decreased, but did not achieve the values of the controls (p<0.05). Fourteen out of eighteen (14/18) children still showed P-gp values above the cut-off level. We also found a positive correlation between the P-gp expression and total prednisone dose in the NS children in all examinations: A: (r=0.540, p<0.05); B: (r=0.630, p<0.01); C: (r=0.653, p<0.01).

CONCLUSION

In conclusion, the overexpression of P-gp in remission, after finishing glucocorticoid treatment, may indicate that P-gp plays a role in the response to corticosteroids in nephrotic children.

Glucocorticoid receptor and vascular endothelial growth factor in nephrotic syndrome

AIM

The aim of the study was to assess plasma and urine concentrations of vascular endothelial growth factor (VEGF) in nephrotic syndrome children (NS) depending on the total dose of glucocorticoids (GC) and the percentage of lymphocytes with glucocorticoid receptor expression (CD3/GCR).

METHODS

We examined 51 children (2-15 years), allocated to three groups: group I: 13 children with the first NS onset, group II: 13 children with NS relapse, group C: 25 healthy children. The NS patients were examined: (A) before treatment and (B) 4-5 weeks after prednisone administration at a dose of 60 mg/m2/24 h. Plasma and urinary VEGF levels were determined using the immunoenzymatic ELISA method. Flow cytometry was applied to assess CD3/GCR expression.

RESULTS

Higher plasma and urinary VEGF concentrations were noted in NS children before treatment (A), as compared to control subjects (C). Following prednisone therapy (B), VEGF level was reduced but it was still higher than in the control group. Positive correlation was observed between VEGF and protein in the urine (group I r = 0.660, P < 0.05, group II r = 0.818, P<0.01) and a weak positive correlation between VEGF in plasma and urine (group I r = 0.531, P<0.05, group II - r = 0.581, P<0.05). CD3/GCR expression was lower in group II. In both groups, the correlation between plasma VEGF and CD3/GCR was positive (P<0.05).

CONCLUSIONS

1. Plasma and urinary VEGF levels increase during nephrotic syndrome onset. 2. Glucocorticoid treatment reduces plasma and urinary VEGF levels in NS children.

Expression of glucocorticoid receptors in nephrotic children depending on total prednisone dose

OBJECTIVE

To evaluate the expression of glucocorticoid receptors (GCR) in lymphocytes (CD3/ GCR) and monocytes (CD14/GCR) in children with nephrotic syndrome (NS).

PATIENTS

The patients were divided into two groups: group I: 17 children with the first NS attack, and group II: 17 children with a subsequent NS event. In both groups, examinations were carried out before treatment (A) and after albuminuria disappearance during prednisone treatment (B). The control group (C) consisted of 23 healthy children, never treated with glucocorticosteroids.

METHODS

Flow cytometry was employed twice to determine the number of CD3+ lymphocytes and CD14+ monocytes and the percentage of CD3/GCR+ and CD14/GCR+ cells.

RESULTS

In group I, the expression of CD3/GCR before treatment (A) decreased during prednisone therapy (B) (p < 0.01), but CD14/GCR did not change. In group II, before treatment (A), both CD3/GCR and CD14/GCR were markedly lower compared to the controls and group I. In examination B, both CD3/GCR and CD14/GCR had decreased.

CONCLUSION

A low number of GCR might confer a worse response to glucocorticoid therapy. Longitudinal studies should be performed on larger groups of children with their first and subsequent nephrotic syndome attacks.

Significance of glucocorticoid receptor expression in colonic mucosal cells of patients with ulcerative colitis

AIM: Glucocorticoid (GC) resistant ulcerative colitis (UC) remains a serious disease and is difficult to manage. Although the molecular basis of GC insensitivity is still unknown, GC receptors (GRα and GRβ) may play an important role in it. This study was aimed to investigate the relationship between the expression of GRα and GRβ in colonic mucosal cells of patients with UC, the efficacy of GC therapy and the intensity of inflammation.

METHODS: Twenty-five cases of UC were classified into: GC sensitive (n = 16) and GC resistant (n = 9) cases. Patients consisted of mild (n = 6), moderate (n = 8) and severe (n = 11) cases. GRα and GRβ expression in colonic mucosal specimens were investigated by immunohistochemistry, and compared between GC resistant and sensitive groups, and also among various degrees of inflammation.

RESULTS: All cases were positive for GRα and GRβ expression. Both positive association between GRα expression and the response of UC to GC and strong negative association between GRβ expression and the response of UC to GC were identified. There was no significant association between GRα/GRβ expression and the degree of inflammation of UC.

CONCLUSION: These findings suggest that both GRα and GRβ may play an important role in the action of GC, and that GRβ functions as a dominant negative inhibitor of GRα. Expression of GRα and GRβ in colonic mucosal cells of patients with UC may serve as predictors of glucocorticoid response, but can not function as markers of inflammatory intensity.