Atypical clinical presentation of a subset of patients with anti-RNA polymerase III - non-scleroderma cases associated with dominant RNA polymerase i reactivity and nucleolar staining

Introduction

Anti-RNA polymerase III (RNAP III) antibodies are highly specific markers of scleroderma (systemic sclerosis, SSc) and associated with a rapidly progressing subset of SSc. The clinical presentation of anti-RNAP III positive patients, onset of Raynaud's phenomenon (RP) and SSc in unselected patients in a rheumatology clinic were evaluated.

Methods

Autoantibodies in sera from 1,966 unselected patients (including 434 systemic lupus erythematosus (SLE), 119 SSc, 85 polymyositis/dermatomyositis (PM/DM)) in a rheumatology clinic were screened by radioimmunoprecipitation. Anti-RNAP III positive sera were also tested by immunofluorescence antinuclear antibodies and anti-RNAP III ELISA. Medical records of anti-RNAP III positive patients were reviewed.

Results

Among 21 anti-RNAP III positive patients, 16 met the American College of Rheumatology (ACR) SSc criteria at the initial visit but 5 did not; diagnoses were vasculitis, early polyarthritis, renal failure with RP, interstitial lung disease, and Sjögren's syndrome. The first two patients developed rapidly progressive diffuse SSc. An additional case presented with diffuse scleroderma without RP and RP developed two years later. Anti-RNAP III antibodies in these 6 cases of atypical clinical presentation were compared with those in 15 cases of typical (SSc with RP) cases. Anti-RNAP III levels by ELISA were lower in the former group (P = 0.04 by Mann-Whitney test) and 3 of 6 were negative versus only 1 of 15 negative in the latter (P < 0.05 by Fisher's exact test). Three cases of non-SSc anti-RNAP III positive patients had predominant reactivity with RNAP I with weak RNAP III reactivity and had a strong nucleolar staining. Three anti-RNAP III patients, who did not have RP at the initial visit, developed RP months later. Scleroderma developed prior to RP in 5 out of 16 (31%) in the anti-RNAP III group, but this was rare in patients with other autoantibodies. The interval between the onset of RP to scleroderma was short in anti-RNAP III positive patients.

Conclusions

Anti-RNAP III antibodies are highly specific for SSc; however, a subset of anti-RNAP III positive patients do not present as typical SSc. The interval between RP and scleroderma in this group is short, and 31% of patients developed scleroderma prior to RP in this group. Anti-RNAP III positive patients may not present as typical SSc and detecting anti-RNAP III may have predictive value.     

Virulence determinants, drug resistance and mobile genetic elements of Laribacter hongkongensis: a genome-wide analysis

Background

Laribacter hongkongensis is associated with community-acquired gastroenteritis and traveler's diarrhea. In this study, we performed an in-depth annotation of the genes in its genome related to the various steps in the infective process, drug resistance and mobile genetic elements.

Results

For acid and bile resistance, L. hongkongensis possessed a urease gene cassette, two arc gene clusters and bile salt efflux systems. For intestinal colonization, it possessed a putative adhesin of the autotransporter family homologous to those of diffusely adherent Escherichia coli (E. coli) and enterotoxigenic E. coli. To evade from host defense, it possessed superoxide dismutase and catalases. For lipopolysaccharide biosynthesis, it possessed the same set of genes that encode enzymes for synthesizing lipid A, two Kdo units and heptose units as E. coli, but different genes for its symmetrical acylation pattern, and nine genes for polysaccharide side chains biosynthesis. It contained a number of CDSs that encode putative cell surface acting (RTX toxin and hemolysins) and intracellular cytotoxins (patatin-like proteins) and enzymes for invasion (outer membrane phospholipase A). It contained a broad variety of antibiotic resistance-related genes, including genes related to β-lactam (n = 10) and multidrug efflux (n = 54). It also contained eight prophages, 17 other phage-related CDSs and 26 CDSs for transposases.

Conclusions

The L. hongkongensis genome possessed genes for acid and bile resistance, intestinal mucosa colonization, evasion of host defense and cytotoxicity and invasion. A broad variety of antibiotic resistance or multidrug resistance genes, a high number of prophages, other phage-related CDSs and CDSs for transposases, were also identified.     

Anti-MJ/NXP-2 autoantibody specificity in a cohort of adult Italian patients with polymyositis/dermatomyositis

Introduction

Autoantibodies in patients with polymyositis/dermatomyositis (PM/DM) are associated with unique subsets, clinical course and outcome. Anti-MJ antibodies, which recognize the nuclear protein NXP-2/MORC3, are reported in ~25% of juvenile DM. Prevalence and clinical significance of anti-MJ antibodies in adult Italian PM/DM patients were studied.

Methods

Sera from 58 consecutive adult Italian PM/DM patients were analyzed by immunoprecipitation of ³⁵S-labeled K562 cells extract, ELISA (anti-MJ, Jo-1), Western blot and indirect immunofluorescence. Clinical associations were analyzed using information from medical charts.

Results

Anti-MJ antibodies were the most prevalent specificity (17%) found mainly in DM (30%, 8 cases) vs 8% of PM (2 cases, P = 0.02). Comparing 10 anti-MJ (+) vs 48 anti-MJ (-) cases, DM was more common (P = 0.03), and age at onset was younger in anti-MJ (+) (P = 0.0006). In anti-MJ (+), heliotrope rash (P = 0.01) and calcinosis (P = 0.09) were more frequent. None of them had heart or lung involvement, or malignancy. Myopathy in anti-MJ (+) patients responded well to therapy and none of them had elevated CPK at last visit (0% vs 25% in anti-MJ (-)). Only 60% of anti-MJ (+) showed immunofluorescent nuclear dots staining, despite PML localization of NXP-2/MORC3.

Conclusions

Anti-MJ antibodies are the most frequent specificity in our cohort of adult Italian PM/DM. Anti-MJ (+) were associated with young onset DM, calcinosis, no internal organ involvement and good response of myopathy to therapy. Anti-MJ reported in juvenile DM is also found in adult PM/DM, and could be a new useful biomarker.     

Ibotenate lesion of the ventromedial hypothalamus lowers hyperthermic effects of prostaglandin E1

This experiment tested the effects of an intracerebroventricular injection of prostaglandin E1 on the sympathetic activation and the thermogenic changes in rats with ibotenate lesions of the ventromedial hypothalamus. Under pentobarbital anesthesia, twelve Sprague-Dawley male rats were lesioned bilaterally in the ventromedial hypothalamus with an injection of ibotenic acid (30 nmol into each side). Sham lesions were carried out in other twelve control rats. After 48 h, all animals were anesthetized with ethyl-urethane. The firing rate of the sympathetic nerves innervating the interscapular brown adipose tissue and the colonic and interscapular brown adipose tissue temperatures were monitored before and after an intracerebroventricular injection of prostaglandin E1 (500 ng) or saline. Prostaglandin E1 induced an increase in the firing rate of sympathetic nerves and the colonic and interscapular brown adipose tissue temperatures. These effects were reduced by the ventromedial hypothalamic lesion. Since ibotenic acid destroys cell bodies, the findings indicate that neurons of the ventromedial hypothalamus play a considerable role in the control of sympathetic activation and the thermogenic changes during prostaglandin E1 hyperthermia.     

Giantin is the major Golgi autoantigen in human anti-Golgi complex sera

Anti-Golgi complex antibodies (AGAs) are primarily associated with systemic lupus erythematosus and Sjögren's syndrome. Here we report on the immunoreactivity of AGAs against five Golgi autoantigens (giantin, golgin-245, golgin-160, golgin-95/GM130, and golgin-97) and provide data from epitope mapping on the most common Golgi autoantigen, namely giantin. A total of 80 human sera containing AGAs, as defined by indirect immunofluorescence on HEp-2 cells, were analyzed by ELISA using recombinant autoantigens and immunoprecipitation. The proportion of AGA sera that reacted with the five Golgi autoantigens was correlated with the molecular mass of the Golgi antigens. Autoantibodies to giantin, the largest Golgi autoantigen, were the predominant AGAs, being found in 50% of the AGA sera. Epitope mapping of giantin was performed using six recombinant fragments spanning the entire protein. Antigiantin-positive sera with low titer autoantibodies recognized epitopes in the carboxyl-terminal fragments that are proximal to the Golgi membrane, whereas higher titer sera exhibited strong reactivity to amino-terminal and central domains that are likely to extend from the Golgi membrane into the cytoplasm. Our working hypothesis is that aberrantly expressed Golgi complex autoantigens may be released into the immune system when cells undergo lysis. By virtue of a carboxyl-terminal transmembrane domain, giantin is likely to be more stably associated with the cytoplasmic face of the Golgi complex than are other golgins, which are peripheral proteins. The stable association of giantin with the putative released Golgi complex may contribute to its preferential autoantigenicity.     

Acute lesions of the ventromedial hypothalamus reduce sympathetic activation and thermogenic changes induced by PGE1

The aim of this experiment was to evaluate the effects of an intracerebroventricular (icv) injection of prostaglandin E1 (PGE₁) on the sympathetic activation and the thermogenic changes in rats with acute lesions of the ventromedial hypothalamus (VMH). Four groups of six Sprague-Dawley male rats were anesthetized with ethyl-urethane. The firing rate of the sympathetic nerves innervating the interscapular brown adipose tissue (IBAT) and the colonic and IBAT temperatures were monitored both before and after one of the following treatments: 1) VMH lesion plus icv injection of PGE₁ (500 ng); 2) VMH lesion plus icv injection of saline; 3) sham lesion plus icv injection of PGE₁; and 4) sham lesion plus icv injection of saline. PGE₁ induced an increase in the firing rate of IBAT nerves and the colonic and IBAT temperatures. These effects were reduced by VMH lesion. The findings indicate that acute lesions of the VMH reduce the effects of PGE₁ and seem to suggest a possible role played by the VMH in the control of the sympathetic activation and the thermogenic changes during PGE₁ hyperthermia.     

Sympathetic and hyperthermic reactions by orexin A: role of cerebral catecholaminergic neurons

This experiment tested the effect of a lesion of cerebral catecholaminergic neurons on the sympathetic and thermogenic effects induced by an intracerebroventicular (icv) injection of orexin A. The firing rates of the sympathetic nerves to the interscapular brown adipose tissue (IBAT), along with IBAT, colonic temperatures and heart rate were monitored in urethane-anesthetized male Sprague-Dawley rats before an injection of orexin A (1.5 nmol) into the lateral cerebral ventricle and over a period of 150 min after the injection. Three days before the experiment, the rats were pre-treated with an icv injection of 6-hydroxydopamine (6-OHDA) or 6-OHDA plus desipramine or saline. The results show that orexin A increases the sympathetic firing rate, IBAT, colonic temperatures and heart rate in the rats pre-treated with saline. This increase is blocked by the pre-treatment with 6-OHDA alone or 6-OHDA plus desipramine. These findings indicate that cerebral catecholaminergic neurons (particularly the dopaminergic pathway) play a fundamental role in the complex reactions related to activation of the orexinergic system.     

Upregulated miR-146a expression in peripheral blood mononuclear cells from rheumatoid arthritis patients

Introduction

MicroRNAs are small noncoding RNA molecules that negatively regulate gene expression via degradation or translational repression of their targeted mRNAs. It is known that aberrant microRNA expression can play important roles in cancer, but the role of microRNAs in autoimmune diseases is only beginning to emerge. In this study, the expression of selected microRNAs is examined in rheumatoid arthritis.

Methods

Total RNA was isolated from peripheral blood mononuclear cells obtained from patients with rheumatoid arthritis, and healthy and disease control individuals, and the expression of miR-146a, miR-155, miR-132, miR-16, and microRNA let-7a was analyzed using quantitative real-time PCR.

Results

Rheumatoid arthritis peripheral blood mononuclear cells exhibited between 1.8-fold and 2.6-fold increases in miR-146a, miR-155, miR-132, and miR-16 expression, whereas let-7a expression was not significantly different compared with healthy control individuals. In addition, two targets of miR-146a, namely tumor necrosis factor receptor-associated factor 6 (TRAF6) and IL-1 receptor-associated kinase 1 (IRAK-1), were similarly expressed between rheumatoid arthritis patients and control individuals, despite increased expression of miR-146a in patients with rheumatoid arthritis. Repression of TRAF6 and/or IRAK-1 in THP-1 cells resulted in up to an 86% reduction in tumor necrosis factor-α production, implicating that normal miR-146a function is critical for the regulation of tumor necrosis factor-α production.

Conclusions

Recent studies have shown that synovial tissue and synovial fibroblasts from patients with rheumatoid arthritis exhibit increased expression of certain microRNAs. Our data thus demonstrate that microRNA expression in rheumatoid arthritis peripheral blood mononuclear cells mimics that of synovial tissue/fibroblasts. The increased microRNA expression in rheumatoid arthritis patients is potentially useful as a marker for disease diagnosis, progression, or treatment efficacy, but this will require confirmation using a large and well defined cohort. Our data also suggest a possible mechanism contributing to rheumatoid arthritis pathogenesis, whereby miR-146a expression is increased but unable to properly function, leading to prolonged tumor necrosis factor-α production in patients with rheumatoid arthritis.