Tsai-Hung Wu

Increased Excretions of β2-Microglobulin, IL-6, and IL-8 and Decreased Excretion of Tamm-Horsfall Glycoprotein in Urine of Patients with Active Lupus nephritis

Tubulointerstitial nephritis is a less frequently recognized but important complication of systemic lupus erythematosus. We have investigated the cytokine β2-microglobulin (β2M) and Tamm-Horsfall glycoprotein (THG) excretions in the urine of systemic lupus erythematosus patients to identify indices for evaluation of tubulointerstitial inflammation in lupus nephritis (LN). Daily urine was collected from 15 patients with active LN, from 12 patients with inactive LN, and from 17 normal subjects. The amounts of soluble interleukin (IL) 2 receptor, IL-6, IL-8, β2M, and THG in urine were measured. β2M and THG were regarded as indicators of proximal and distal renal tubule function, respectively. The urinary excretions of IL-6 and IL-8 were significantly higher in patients with active LN than in those with inactive LN and in normal individuals. The excretion of soluble IL-2 receptor in all three groups of subjects was not significantly different. On the other hand, the excretion of β2M in patients with LN was significantly higher than that in normal individuals. The excretion of β2M in patients with active or inactive LN was not significantly different. The THG excretion was lower in patients with active LN and tubulointerstitial inflammation as compared with patients with inactive LN or normal individuals. Six patients underwent pulse cyclophosphamide therapy during the course of experiments. Five of them showed a decrease in IL-8 and IL-6 excretions in urine after the treatment. The excretions of β2M and THG in urine, in addition to IL-6 and IL-8, can reflect the renal inflammatory activity in patients with lupus tubulointerstitial nephritis as well as in those having lupus glomerulonephritis.

Cerebrospinal Fluid lnterleukin-6, Prostaglandin E2 and Autoantibodies in Patients with Neuropsychiatric Systemic Lupus Erythematosus and Central Nervous System Infections

Cerebrospinal fluid (CSF) from patients with a variety of central nervous system (CNS) disorders was assayed for cytokines, prostaglandins, and autoantibodies. CSF interleukin-6 (IL-6) in patients with CNS infection (374.24 ± 92.61 pg/mL) and neuropsychiatric systemic lupus erythematosus (NP-SLE) (71.40 ± 5.89 pg/mL) were significantly higher than in patients with CNS inflammation (33.92 ± 29.36 pg/mL) or controls (non-inflammatory CNS diseases) (4.35 ± 3.00 pg/mL). Interleukin-1β, interferon α, and tumor necrosis factor α were undetectable in these samples: CSF prostaglandin E2 (PGE2) also exhibited similar patterns as IL-6. CSF immunoglobulin G (IgG) in patients with NP-SLE (8.84 ± 1.80 mg/dL) was much higher than in patients with CNS infection (4.65 ± 3.09 mg/dL), CNS inflammation (2.54 ± 1.24 mg/dL), or controls (2.11 ± 1.03 mg/dL). CSF autoantibodies against calf thymus antigens were present in patients with NP-SLE but not in patients with CNS infection as demonstrated by immunoblot. These results su...

Increased Excretion of Tumor Necrosis Factor Alpha and Interleukin 1 β in Urine from Patients with IgA Nephropathy and Schönlein-Henoch Purpura

Urinary proteins (5 mg/ml) collected from a group of 16 patients including 13 with IgA nephropathy and 3 with Schönlein-Henoch purpura (SHP) and from a control group consisting of 6 patients with diabetic nephropathy, 5 patients with hypertensive nephrosclerosis, and 5 healthy hospital staff members were studied for the contents of interleukins (IL) 1 beta, 2, 4, 6, and 12 and tumor necrosis factor alpha (TNF-alpha). Eleven patient with IgA nephropathy or SHP (11/16) but only 1 of the controls (1/16) had TNF-alpha activity in urinary proteins (p < 0.01). The IL-1 beta activity exhibited a similar tendency but to a lesser extent (10 of 16 patients with IgA nephropathy or SHP vs. 2 of 16 with other conditions, p < 0.05). Conversely, the detection rates of IL-2, IL-4, and IL-6 in both groups were not significantly different. IL-12 was not found in any of the samples from both groups. Sera and nonpurified urine samples from the same individuals were also measured for cytokines. IL-1 beta, IL-2, IL-4, and IL-12 were absent in all these samples, but TNF-alpha was found in four of the serum samples from patients with IgA nephropathy. Urinary proteins (2 mg/ml) were analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereby peptides of 52, 49, 45, 34, 30, and 11 kD could be demonstrated in the patients with IgA nephropathy or SHP. Urinary proteins (200 micrograms/ml from patients with IgA nephropathy or SHP exerted a mitogen-like effect on the normal human mononuclear cells, as demonstrated by 3H-thymidine incorporation. In addition, these urinary proteins (400 micrograms/ml) enhanced the proliferative activity of the cultured rat glomerular mesangial cells. The exaggerated proliferation of rat glomerular mesangial cells exerted by urine proteins from 2 patients with active disease was markedly suppressed after treatment with glucocorticoids/cyclophosphamide. These results suggest that patients with IgA nephropathy or SHP can excrete excessive amounts of TNF-alpha and IL-1 beta in the urine. The inconsistent presence of these two cytokines in urine and serum may indicate that they can be produced locally and that they are implicated in the development of mesangial inflammation and glomerular damage.

Serum BLC/CXCL13 Concentrations and Renal Expression of CXCL13/CXCR5 in Patients with Systemic Lupus Erythematosus and Lupus Nephritis

Objective. Systemic lupus erythematosus (SLE) is a prototype of systemic autoimmune disease in which cytokines such as B lymphocyte chemoattractant (BLC, or CXC motif ligand 13, CXCL13) may play important roles in pathogenesis. We investigated the implications of CXCL13 in SLE and lupus nephritis. Methods. Serum samples from 425 patients with SLE and 106 healthy control individuals were analyzed for the concentration of CXCL13 by ELISA. Tissue expression of CXCL13 and its corresponding receptor CXCR5 were observed in lupus kidney. The CXCR5-bearing B cells in SLE patients were analyzed by flow cytometry. Results. Serum levels of CXCL13 were higher in SLE patients compared to controls. SLE patients with lupus nephritis or positive anti-dsDNA antibodies had significantly higher serum CXCL13 levels. The peripheral venous blood B cells that bear CXCR5 were more abundant in SLE patients as detected by flow cytometry. CXCR5 and CXCL13 were highly expressed in the renal cortex from patients with lupus nephritis. Conclusions. Our results suggest that BLC/CXCL13 as well as its corresponding receptor, CXCR5, may play important roles in the pathogenesis of SLE and in lupus nephritis.

Effect of antibodies to double stranded DNA, purified from serum samples of patients with active systemic lupus erythematosus, on the glomerular mesangial cells.

Polyclonal antibodies to double stranded DNA (dsDNA) purified from pooled serum samples of patients with systemic lupus erythematosus (SLE) exerted cytotoxic effects on cultured rat mesangial cells. At concentrations from 5 to 150 IU/ml, antibodies to dsDNA inhibited the incorporation of thymidine labelled with 3H into rat mesangial cells in a dose response manner after three days of culture. In contrast, normal human IgG (1 mg/ml), heat aggregated human IgG (1 mg/ml), N-formyl-methionyl-leucyl-phenylalanine (1 x 10(-7) mol/l), tumour necrosis factor alpha (16 U/ml), lipopolysaccharides (1 microgram/ml), 4 beta-phorbol-12 beta-myristate-13 alpha-acetate (PMA) (20 ng/ml), interleukin 1 beta (10 U/ml), and 20% v/v phytohaemagglutinin stimulated mononuclear cell supernatant showed no significant effect on these cells. Anticardiolipin antibody, another autoantibody purified from the serum of patients with SLE, also inhibited the proliferation of rat mesangial cells but to a lesser extent. In the presence of antibodies to dsDNA (100 IU/ml), the mesangial cells became spherical and clustered together, which was very different from the original stellate appearance. These autoantibodies also depolarised the membrane potential of mesangial cells. Antibodies to dsDNA decreased the syntheses of prostaglandin E2, 6-keto-prostaglandin F1 alpha and thromboxane B2 by mesangial cells. In an in vivo study, the antibodies to dsDNA showed a strong affinity for the glomeruli when intravenously injected into rats. These results suggest that the nephrotropic antibodies to dsDNA can directly damage the glomerular mesangial cells in addition to the formation of immune complexes with DNA which may cause kidney inflammation and tissue destruction.

Increased excretion of soluble interleukin 2 receptors and free light chain immunoglobulins in the urine of patients with active lupus nephritis.

Samples of protein from the urine of 23 patients with lupus nephropathy and 15 patients with proteinuria who did not have systemic lupus erythematosus (SLE) were studied for the presence of cytokines, soluble interleukin 2 receptors (sIL-2R), and free light chain immunoglobulins. The patients with lupus nephropathy were divided into two groups with active (nephritis) and inactive inflammation (nephrosis) based on the results of the analysis of urine samples and renal histology. The crude urine proteins (5 mg/ml) after precipitation by 80% ammonium sulphate from 14 patients with lupus nephritis contained higher concentrations of sIL-2R (4.88 (SEM 1.27 ng/ml) than those from nine patients with nephrosis (1.11 (0.52) ng/ml) or 15 patients without SLE (1.31 (0.87) ng/ml). The concentration of sIL-2R in protein from urine samples was not correlated with the concentration in plasma and was inversely correlated with the excretion of protein in urine over 24 hours in patients with SLE. It is suggested that, in addition to leakage from the circulation, the local production of sIL-2R by inflamed kidneys is possible. The crude proteins in urine were further fractionated by gel filtration on Sephacryl S-200. Arbitrarily, four fractions could be obtained from urine from patients with SLE but only three fractions were found in the urine of patients without SLE. Fraction IV derived from patients with nephritis or nephrosis augmented the pokeweed mitogen induced [3H]thymidine uptake of mononuclear cells. In addition, the positive rates of free kappa (kappa) (35.7%) and lambda (lambda) (42.9%) chains in proteins in urine from nephritic patients were higher than those in the other two groups. These results suggest that the severity of inflammation in the kidneys of patients with lupus can be reflected by the increased excretion of sIL-2R, free light chain immunoglobulins, and cytokine-like molecules in urine.

DECREASED IL-12 PRODUCTION BY POLYMORPHONUCLEAR LEUKOCYTES IN PATIENTS WITH ACTIVE SYSTEMIC LUPUS ERYTHEMATOSUS

Polymorphonuclear leukocytes (PMN) play an important role in eradicating bacterial infections. To test if PMN of patients with systemic lupus erythematosus (SLE) have defective capacity to produce IL-12, IL-12 p35 gene transcription and p70 excretion by PMN were evaluated in SLE patients and normal subjects. Peripheral blood PMN from 25 patients with active SLE and 25 normal individuals were stimulated with lipopolysaccharide (LPS, 100 ng/mL) in the presence or absence of recombinant interferon (IFN)-γ (5–200 IU/mL). The IL-12 p35 gene transcripts were analyzed by reverse transcription – polymerase chain reaction (RT-PCR) and the IL-12 p70 in culture supernatants was quantified by enzyme immunoassay (EIA). At the 6th hour of stimulation, IL-12 expression in PMN of SLE patients was less prominent than that of the normal controls. The IL-12 was produced by normal PMN on LPS stimulation in the absence of IFN-γ. IFN-γ enhanced the IL-12 production by normal PMN stimulated with LPS, but it inhibited the IL-12 production in PMN from active lupus patients in the presence of LPS. Analysis with PCR using the same primers on the chromosomal DNA showed that p35 gene was intact in SLE patients. These results have suggested that SLE-PMN may have defect in IL-12 expression and the defect may be exaggerated in the presence of IFN-γ which normally stimulates IL-12 production. This may account for increased susceptibility to multiple infections in patients with active SLE.

Abnormal in vitro CXCR2 modulation and defective cationic ion transporter expression on polymorphonuclear neutrophils responsible for hyporesponsiveness to IL-8 stimulation in patients with active systemic lupus erythematosus

OBJECTIVE To elucidate the molecular basis of hyporesponsiveness of polymorphonuclear neutrophils (PMN) to interleukin-8 (IL-8) stimulation in patients with active SLE. METHODS PMN obtained from active SLE and well-matched healthy individuals were studied. The expression of two IL-8 receptors, CXCR1 and CXCR2, in PMN were detected by flow cytometry and reverse transcriptase-polymerase chain reaction. The binding affinity of PMN with IL-8 was calculated by Scatchard plotting. Soluble CXCR2 level in IL-8-stimulated PMN culture supernatant was measured by sandwich enzyme-linked immunosorbent assay. The resting and IL-8-stimulated membrane potential (MP) changes, and membrane expression of cationic ion transporters including Na+-K+-ATPase, renal epithelial Na+ channel (ENaC) and renal outer medullary epithelial K+ channel 1 (ROMK1) on PMN were detected by flow cytometry. RESULTS Compared with normal PMN, decreased CXCR2 gene expression, but normal IL-8-binding affinity of SLE-PMN, was found. For exploring the molecular basis of the defect, the modulation of CXCR2 in SLE-PMN was intensively investigated. We found that increased cytosolic CXCR2 expression in SLE-PMN was due to defective surface translocation, increased spontaneous internalization and/or increased spontaneous synthesis. The IL-8-induced CXCR2 down-regulation in SLE-PMN was also impaired due to decreased proteolytic cleavage of IL-8-IL-8 receptor complexes from the cell surface whereas IL-8-induced internalization of the complexes was normal. In addition, we originally found that increased resting but decreased IL-8-stimulated MP in SLE-PMN was relevant to defective expression of Na+-K+-ATPase, ENaC and ROMK1 on the cell surface. CONCLUSION The abnormal CXCR2 modulation and impaired cationic ion transporter expression cause SLE-PMN hyporesponsiveness to IL-8 stimulation in vitro.

Polyclonal anticardiolipin antibodies purified from sera of patients with active systemic lupus erythematosus induce apoptosis of the cultured glomerular mesangial cells

Objective: To test the effect of anticardiolipin antibodies (aCL) on cultured glomerular mesangial cells with regard to their expression of apoptosis-related genes. Methods: aCL puri®ed from active lupus sera by cardiolipin micelles were incubated with cultured rodent mesangial cells (RMC). Morphological changes of the RMC were observed. The genomic DNA was extracted for the detection of apoptosis. The total cell RNA was extracted for detection of Fas, c-myc, p53, and bcl-2 transcripts by reverse transcription-polymerase chain reaction. Results: aCL (100 GPL-U/0.1 mg protein/ml) bound to RMC more prominent than human IgG (100mg/ml). The antibodies suppressed RMC proliferation in a dose-dependent manner. The RMC were undergoing apoptosis as evidenced by morphologic changes, ̄uoresceinannexin V staining and appearance of nucleosome-sized DNA fragments. RMC spontaneously express p53 and c-myc but not Fas or bcl-2. aCL (100 GPL-U/ml) enhanced the expression of Fas but not other apoptosis-related genes and suppressed the intracellular tyrosine phosphorylation. Conclusions: Binding of aCL can induce apoptosis of the RMC. The aCL may be implicated in the pathogenesis of lupus nephritis.OBJECTIVE To test the effect of anticardiolipin antibodies (aCL) on cultured glomerular mesangial cells with regard to their expression of apoptosis-related genes. METHODS aCL purified from active lupus sera by cardiolipin micelles were incubated with cultured rodent mesangial cells (RMC). Morphological changes of the RMC were observed. The genomic DNA was extracted for the detection of apoptosis. The total cell RNA was extracted for detection of Fas, c-myc, p53, and bcl-2 transcripts by reverse transcription-polymerase chain reaction. RESULTS aCL (100 GPL-U/0.1 mg protein/ml) bound to RMC more prominent than human IgG (100 microg/ml). The antibodies suppressed RMC proliferation in a dose-dependent manner. The RMC were undergoing apoptosis as evidenced by morphologic changes, fluoresceinannexin V staining and appearance of nucleosome-sized DNA fragments. RMC spontaneously express p53 and c-myc but not Fas or bcl-2. aCL (100 GPL-U/ml) enhanced the expression of Fas but not other apoptosis-related genes and suppressed the intracellular tyrosine phosphorylation. CONCLUSIONS Binding of aCL can induce apoptosis of the RMC. The aCL may be implicated in the pathogenesis of lupus nephritis.

The pathogenesis of systemic lupus erythematosus - From the viewpoint of oxidative stress and mitochondrial dysfunction.

SLE is characterized by an increased production of detrimental autoantigens, exaggerated effects of pro-inflammatory cytokines, dysregulated functioning of immunocompetent cells including lymphocytes and leukocytes, and devastating tissue and organ damage. All of these derangements can be potentiated or attenuated by the abnormal energy expenditure and overproduction of reactive oxygen species (ROS). Mitochondrial heteroplasmy or dysfunction has been recognized to play a role in these abnormalities. Abnormal redox reaction, decreased functioning of biogenesis-related enzymes, increased NETosis, harmful cytokine effects, and aberrant lymphocyte behavior have been shown to be associated with the pathological state of mitochondria. There is accumulating data which support the importance of abnormal oxygen metabolism and mitochondrial disorders in the immunopathogenesis of SLE. Further laboratory as well as clinical data are required to expand our understanding of SLE pathogenesis.