Nakajo-Nishimura syndrome (NNS) is a disorder that segregates in an autosomal recessive fashion. Symptoms include periodic fever, skin rash, partial lipomuscular atrophy, and joint contracture. Here, we report a mutation in the human proteasome subunit beta type 8 gene (PSMB8) that encodes the immunoproteasome subunit β5i in patients with NNS. This G201V mutation disrupts the β-sheet structure, protrudes from the loop that interfaces with the β4 subunit, and is in close proximity to the catalytic threonine residue. The β5i mutant is not efficiently incorporated during immunoproteasome biogenesis, resulting in reduced proteasome activity and accumulation of ubiquitinated and oxidized proteins within cells expressing immunoproteasomes. As a result, the level of interleukin (IL)-6 and IFN-γ inducible protein (IP)-10 in patient sera is markedly increased. Nuclear phosphorylated p38 and the secretion of IL-6 are increased in patient cells both in vitro and in vivo, which may account for the inflammatory response and periodic fever observed in these patients. These results show that a mutation within a proteasome subunit is the direct cause of a human disease and suggest that decreased proteasome activity can cause inflammation.
؉ monocyte/macrophage accumulation were significantly inhibited by endostatin peptide. Increase in the renal expression of VEGF-A, flk-1, Ang-2, an antagonist of angiopoietin-1, transforming growth factor-1, interleukin-6, and monocyte chemoattractant protein-1 was inhibited by endostatin peptide in diabetic mice. Decrease of nephrin mRNA and protein in diabetic mice was suppressed by treatment with endostatin peptide. The level of endostatin in the renal cortex and sera was increased in diabetic mice. Endogenous renal levels of endostatin were decreased in endostatin peptide-treated groups in parallel with VEGF-A. Although serum levels of endostatin were decreased in the low-dose endostatin-peptide group, high-dose administration resulted in elevated serum levels of endostatin. These results demonstrate the potential use of antiangiogenic endostatin peptide as a novel therapeutic agent in diabetic nephropathy.
ObjectivesWe investigated the relationships among M1 monocytes, M2 monocytes, osteoclast (OC) differentiation ability, and clinical characteristics in patients with rheumatoid arthritis (RA).MethodsPeripheral blood mononuclear cells (PBMCs) were isolated from RA patients and healthy donors, and we then investigated the number of M1 monocytes or M2 monocytes by fluorescence-activated cell sorting. We also obtained and cultured CD14-positive cells from PBMCs from RA patients and healthy donors to investigate OC differentiation in vitro.ResultsForty RA patients and 20 healthy donors were included. Twenty-two patients (55%) were anticitrullinated protein antibody (ACPA) positive. The median M1/M2 ratio was 0.59 (0.31–1.11, interquartile range). There were no significant differences between the RA patients and healthy donors. There was a positive correlation between the M1/M2 ratio and the differentiated OC number in vitro in RA patients (ρ = 0.81, p < 0.001). The ACPA-positive patients had significantly higher M1/M2 ratios in vivo (p = 0.028) and significantly greater numbers of OCs in vitro (p = 0.005) than the ACPA-negative patients. Multivariable regression analysis revealed that the M1/M2 ratio was the sole significant contribution factor to in vitro osteoclastogenesis. RA patients with M1/M2 ratios >1 (having relatively more M1 monocytes) had higher C-reactive protein and erythrocyte sedimentation rates than RA patients with M1/M2 ratios ≤1. M1-dominant monocytes in vitro produced higher concentrations of interleukin-6 upon stimulation with lipopolysaccharide than M2 monocytes.ConclusionM1/M2 monocytes imbalance strongly contributes to osteoclastogenesis of RA patients. Our findings cast M1 and M2 monocyte subsets in a new light as a new target of treatments for RA to prevent progression of osteoclastic bone destruction.
Objective. To evaluate whether magnetic resonance imaging (MRI) of the wrists and finger joints and an analysis of serologic autoantibodies are clinically meaningful for the subsequent development of rheumatoid arthritis (RA) in patients with undifferentiated arthritis (UA). Methods. A total of 129 patients with UA, a disease status formally confirmed by a rheumatologist over a period of at least 1 year, were included. Gadolinium-diethylenetriamine-enhanced MRI of both wrists and finger joints and serologic variables were examined upon admission to our Early Arthritis Clinic at Nagasaki University. After a prospective followup of 1 year, a predictive value for the development of RA was determined for each patient. Results. The subjects were evaluated for their positive or negative status with respect to 3 objective measures at study entry: anti-cyclic citrullinated peptide (anti-CCP) antibodies and/or IgM-rheumatoid factor, MRI-proven symmetric synovitis, and MRI-proven bone edema and/or bone erosion. The patients who were positive for at least 2 of these measures progressed to RA at 1 year with a 79.7% positive predictive value (PPV), 63.0% negative predictive value, 75.9% specificity, 68.0% sensitivity, and 71.3% accuracy. Furthermore, in 22 UA patients positive for both anti-CCP antibodies and MRI-proven bone edema who were considered to have progressed to RA at 1 year, the PPV was increased to 100%. A close correlation was found between the present rule and that established in the Leiden Early Arthritis Cohort. Conclusion. MRI-proven early joint damage in conjunction with serologic autoantibodies is efficient in predicting progression from UA to RA. This method can be used to identify patients who would benefit from early treatment with disease-modifying antirheumatic drugs. INTRODUCTIONEarly undifferentiated arthritis (UA) is defined as early arthritis that does not fulfill the classification criteria for a more definitive diagnosis, according to the 1987 American College of Rheumatology (ACR; formerly the American Rheumatism Association) criteria for rheumatoid arthritis (RA) (1-3). The natural disease course of UA is variable; therefore, to minimize under-and overtreatment of patients with UA, a model was recently constructed by the Leiden Early Arthritis Cohort to estimate the likelihood of progression to RA in individual patients (2,3). Their prediction rule consists of 9 clinical variables: sex, age, localization of symptoms, morning stiffness, tender joint count, ISRCTN: 021008-1.
This is the first study to report, in a single cohort of DM patients, that distinct clinical subsets are distributed in an anti-155/140 Ab-positive group, an anti-140 Ab-positive group, or an anti-ARS Ab-positive group. Our data also confirm previous evidence that anti-155/140 Abs are involved in malignancies and that anti-140 Abs are involved in rapidly progressive ILD.
The activity of calcium/calmodulin-dependent protein kinase IV (CaMK4) is increased in T cells from patients with SLE and has been shown to reduce IL-2 production by promoting the effect of the transcriptional repressor cAMP responsive element modulator (CREM)-α on the IL2 promoter. Here we demonstrate that T cells from MRL/lpr mice display increased levels of CaMK4 in the nucleus and that genetic deletion of Camk4 results in improved survival. We demonstrate that absence of CaMK4 restores IL-2 production, curbs increased T cell activation, and augments the number and activity of regulatory T cells. Analogously, silencing of CaMK4 in T cells from patients with SLE increases the expression of FoxP3 upon stimulation in the presence of TGF-β. Our results demonstrate the importance of the serine/threonine kinase CaMK4 in the generation and function of regulatory T cells in patients with SLE and lupus-prone mice and its potential to serve as a therapeutic target.
Type 1 diabetes mellitus is an autoimmune disease characterized by progressive destruction of pancreatic beta cells by genetic and environmental factors which leads to an absolute dependence of insulin for survival and maintenance of health. Although the majority of mechanisms of beta cell destruction remain unclear, many molecules, including proinflammatory cytokines and chemokines such as tumor necrosis factor alpha and monocyte chemoattractant protein-1, are implicated in the development of beta cell damage. Furthermore, beta cell destruction is enhanced by the Th1 and Th17 subsets of CD4+ T cells. In contrast, there are mechanisms involved in the maintenance of peripheral tolerance by regulatory T cells, the function of which depends on the pleiotropic cytokine transforming growth factor beta. Development and progression of renal injuries in patients with diabetic nephropathy are also associated with several growth factors and proinflammatory cytokines, including tumor necrosis factor alpha, insulin-like growth factor-1, monocyte chemoattractant protein-1, vascular endothelial growth factor, and transforming growth factor beta. Although the pathogenic mechanisms underlying type 1 diabetes and diabetic nephropathy are principally different, i.e., autoimmunity and inflammation, some common factors, including susceptibility genes and proinflammatory cytokines, are involved in both mechanisms, including infiltrating cell recruitment, upregulation of other cytokines and chemokines, or apoptosis.
Systemic lupus erythematosus (SLE) is a complex autoimmune disease with numerous abnormalities recorded at the cellular, molecular, and genetic level. Expression of the basic leucine zipper transcription factor cAMP-responsive element modulator (CREM)␣ was reported to be abnormally increased in T cells from SLE patients. CREM␣ suppresses IL-2 and T cell receptor chain gene transcription by direct binding to the respective promoters. Here, we show that increased CREM expression is the result of enhanced promoter activity. DNA binding analyses reveal direct binding of transcription factor specificity protein-1 (SP-1) to the CREM promoter resulting in enhanced transcriptional activity and increased CREM expression. Protein phosphatase 2A is known to activate SP-1 through dephosphorylation at its serine residue 59. Our results show that nuclei from SLE T cells contain lower levels of Ser 59 -phosphorylated SP-1 protein and a stronger SP-1 binding to the CREM promoter. We conclude that protein phosphatase 2A accounts for enhanced SP-1 dephosphorylation at Ser 59 in SLE T cells. More importantly, CREM promoter activity mirrors reliably disease activity in SLE patients, underscoring its potential role as a biomarker for the prediction of flares in SLE patients. Systemic lupus erythematosus (SLE)3 is a chronic inflammatory disease characterized by an autoimmune process affecting every organ, including joints, kidneys, skin, and the central nervous system (1). T cells have been demonstrated to be important in the pathogenesis of SLE (2). Functional abnormalities in SLE T cells are largely underwritten by altered gene transcription, and recent studies have revealed a vast number of transcription factors in SLE T cells displaying changes in their expression levels and function. Among them, the ␣-isoform of the transcriptional regulator cAMP-responsive element modulator (CREM) has emerged as a potent regulator of target genes that are crucially involved in T cell physiology, e.g. interleukin (IL)-2, T cell receptor chain, and transcription factor c-fos (3-5).The CREM protein family constitutes a group of transcription factors that belong to the superfamily of basic domain/ leucine zipper domain proteins such as cAMP-responsive element-binding protein (CREB) and activating transcription factors. All of them share high structural similarities and possess the ability to bind specifically cis-regulatory DNA sequences as homo-or heterodimers. The target motifs are palindromic DNA sequences denoted cAMP response elements (CRE, TGACGTCA) as well as the 5Ј-TGAC half-sites of this palindrome, both of which are highly conserved within numerous promoters of eukaryotic genes (6). Increased intracellular cAMP levels stimulate a multitude of kinases, e.g. calmodulin kinase IV, that subsequently phosphorylate and thereby activate CREM (7).Previous studies from our group have provided evidence that CREM␣ expression is increased in T cells from SLE patients (8). We have shown that CREM␣ binds to the Ϫ180 site of the IL-2 promoter in SLE T c...
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