RNA binding protein DDX5 restricts RORγt+ Treg suppressor function to promote intestine inflammation

Retinoid-related orphan receptor (RAR) gamma (RORγt)-expressing regulatory T cells (RORγt+ Tregs) play pivotal roles in preventing T cell hyperactivation and maintaining tissue homeostasis, in part by secreting the anti-inflammation cytokine interleukin-10 (IL-10). Here, we report that hypoxia-induced factor 1α (HIF1α) is the master transcription factor for Il10 in RORγt+ Tregs. This critical anti-inflammatory pathway is negatively regulated by an RNA binding protein DEAD box helicase 5 (DDX5). As a transcriptional corepressor, DDX5 restricts the expression of HIF1α and its downstream target gene Il10 in RORγt+ Tregs. T cell-specific Ddx5 knockout (DDX5ΔT) mice have augmented RORγt+ Treg suppressor activities and are better protected from intestinal inflammation. Genetic ablation or pharmacologic inhibition of HIF1α restores enteropathy susceptibility in DDX5ΔT mice. The DDX5-HIF1α-IL-10 pathway is conserved in mice and humans. These findings reveal potential therapeutic targets for intestinal inflammatory diseases.

RORγt phosphorylation protects against T cell-mediated inflammation

RAR-related orphan receptor-γ (RORγt) is an essential transcription factor for thymic T cell development, secondary lymphoid tissue organogenesis, and peripheral immune cell differentiation. Serine 182 phosphorylation is a major post-translational modification (PTM) on RORγt. However, the in vivo contribution of this PTM in health and disease settings is unclear. We report that this PTM is not involved in thymic T cell development and effector T cell differentiation. Instead, it is a critical regulator of inflammation downstream of IL-1β signaling and extracellular signal regulated kinases (ERKs) activation. ERKs phosphorylation of serine 182 on RORgt serves to simultaneously restrict Th17 hyperactivation and promote anti-inflammatory cytokine IL-10 production in RORγt⁺ Treg cells. Phospho-null RORγt^S182A knockin mice experience exacerbated inflammation in models of colitis and experimental autoimmune encephalomyelitis (EAE). In summary, the IL-1β-ERK-RORγt^S182 circuit protects against T cell-mediated inflammation and provides potential therapeutic targets to combat autoimmune diseases.

A balanced mucosal T cell population is essential for tissue homeostasis and wound healing post-injury and infection. In this study, Ma et al. report a surprising role for the phosphorylated transcription factor RORγt as a cell-intrinsic regulator for maintaining mucosal T cell heterogeneity and promoting inflammation resolution.

Ribosomal protein S3 associates with the TFIIH complex and positively regulates nucleotide excision repair

In mammalian cells, the bulky DNA adducts caused by ultraviolet radiation are mainly repaired via the nucleotide excision repair (NER) pathway; some defects in this pathway lead to a genetic disorder known as xeroderma pigmentosum (XP). Ribosomal protein S3 (rpS3), a constituent of the 40S ribosomal subunit, is a multi-functional protein with various extra-ribosomal functions, including a role in the cellular stress response and DNA repair-related activities. We report that rpS3 associates with transcription factor IIH (TFIIH) via an interaction with the xeroderma pigmentosum complementation group D (XPD) protein and complements its function in the NER pathway. For optimal repair of UV-induced duplex DNA lesions, the strong helicase activity of the TFIIH complex is required for unwinding damaged DNA around the lesion. Here, we show that XP-D cells overexpressing rpS3 showed markedly increased resistance to UV radiation through XPD and rpS3 interaction. Additionally, the knockdown of rpS3 caused reduced NER efficiency in HeLa cells and the overexpression of rpS3 partially restored helicase activity of the TFIIH complex of XP-D cells in vitro. We also present data suggesting that rpS3 is involved in post-excision processing in NER, assisting TFIIH in expediting the repair process by increasing its turnover rate when DNA is damaged. We propose that rpS3 is an accessory protein of the NER pathway and its recruitment to the repair machinery augments repair efficiency upon UV damage by enhancing XPD helicase function and increasing its turnover rate.

DDX5 promotes oncogene C3 and FABP1 expressions and drives intestinal inflammation and tumorigenesis

Tumorigenesis in different segments of the intestinal tract involves tissue-specific oncogenic drivers. In the colon, complement component 3 (C3) activation is a major contributor to inflammation and malignancies. By contrast, tumorigenesis in the small intestine involves fatty acid-binding protein 1 (FABP1). However, little is known of the upstream mechanisms driving their expressions in different segments of the intestinal tract. Here, we report that the RNA-binding protein DDX5 binds to the mRNA transcripts of C3 and Fabp1 to augment their expressions posttranscriptionally. Knocking out DDX5 in epithelial cells protected mice from intestinal tumorigenesis and dextran sodium sulfate (DSS)-induced colitis. Identification of DDX5 as a common upstream regulator of tissue-specific oncogenic molecules provides an excellent therapeutic target for intestinal diseases.

Treatment guidelines for isolated dissection of the superior mesenteric artery based on follow-up CT findings

OBJECTIVES

The treatment guidelines for isolated superior mesenteric artery dissection (SMAD) are not well established. The purpose of this study was to report a single-centre series of SMAD and propose treatment guidelines.

MATERIALS AND METHODS

Between November 2004 and December 2009, 30 patients were diagnosed with SMAD. We retrospectively reviewed their medical records.

RESULTS

The subjects included 26 men and four women, with a mean age of 55.1 years. The chief complaint was abdominal pain in 17 patients, whereas 13 patients were asymptomatic. The mean follow-up was 38.3 months. The radiographic findings included intimal flap with a false lumen in 20 patients and intramural haematoma in 10 patients. The treatments included observation in 18 patients, anticoagulation in five patients, stenting in six patients and surgery in one patient. During follow-up (mean 15.6 months), there was no change in the computed tomography scans of seven patients, improvement was observed in four patients and complete resolution was observed in four patients. All patients, including the symptomatic patients, remained asymptomatic during follow-up.

CONCLUSIONS

Most patients with SMAD can be successfully managed with conservative treatment. Surgical treatment or percutaneous intervention can be reserved for patients with severe mesenteric ischaemia and those for whom the initial conservative treatment fails.

Congenital cystic adenomatoid malformation (Type II) with active tuberculosis in an adult

Cystic adenomatoid malformation (CAM) is a congenital disorder similar to bronchopulmonary sequestration. Most cases of CAM are diagnosed during the neonatal period and infancy. The histological classification of the vast majority of reported cases of CAM is Stocker's Type I. We present an adult patient with Stocker's Type II CAM with active tuberculosis.

School urinalysis screening in Korea: prevalence of chronic renal disease

Since 1998, mass urine screening tests have been performed on Korean school children. We have analyzed those patients who showed abnormal urinary findings in the school screening program. Between January 1998 and January 2000, 452 children with abnormal urinary findings visited the Pediatric Kidney Center, Kyung-Hee University Hospital. Sex, age, 24-h urine creatinine clearance, ultrasonography, Doppler scans and renal biopsies were reviewed retrospectively. Results of initial urinalysis are divided into three groups: solely hematuria group (228 cases, 50.4%), solely proteinuria group (98 cases, 21.7%), and combined hematuria and proteinuria group (79 cases, 17.5%). Among the biopsied cases, the proportions representing renal parenchymal diseases were as follows: IgA nephropathy 11.3%, mesangial proliferative glomerulonephritis 21.9%, others 3.8%. Among the three groups, the combined hematuria and proteinuria group had more frequent chronic renal disease (57.7%) than the other groups. Chronic renal disease was detected in 36.9% of all visiting subjects. In the school screening program a significant number of patients showed abnormal urinary findings, which were associated with chronic renal diseases especially in the combined hematuria and proteinuria group. In conclusion, mass urine screening tests should be mandatory to detect asymptomatic chronic renal disease in school children.

Diagnosis of nut-cracker phenomenon using renal Doppler ultrasound in orthostatic proteinuria

BACKGROUND

We evaluated the efficacy of non-invasive renal Doppler ultrasound (US) to detect the nut-cracker phenomenon (NCP) and we studied the prevalence of NCP in children with orthostatic proteinuria.

METHODS

Among a total 66 cases of orthostatic proteinuria, 39 cases of NCP were found, with 27 cases being detected in a normal control group. Using Doppler US, the anteroposterior (AP) diameter and peak velocity (PV) of the left renal vein (LRV) were measured at the hilar and aortomesenteric portion. We calculated the ratio of AP and PV diameters between the two portions. The parameters were analysed using Student's t-test.

RESULTS

The AP diameters and the ratio in the hilar and narrow portions were all significantly different between the two groups (P<0.01). The PV in the narrow portion and the ratio of PV were significantly different (P<0.01), but the PV in the hilar portion was not statistically different between the two groups (P>0.05). If the diagnostic criteria for NCP was that the ratio of PV was more than 5, then 22 subjects (56.4%) in the orthostatic proteinuria group and none in the control group could be diagnosed as NCP. If, however, the cut-off values for the diagnosis of NCP were set at the mean+/-2 SD of the ratio (PV ratio 3.98 and size ratio 4.16), then the orthostatic proteinuria group showed abnormal AP diameter in 25 (64.1%), peak velocity in 28 (71.8%), and both in 21 patients (53.8%), and the control group showed an abnormal AP diameter in one subject (3.7%).

CONCLUSIONS

NCP may be one of the leading causes of orthostatic proteinuria, and non-invasive renal Doppler US may be a useful diagnostic tool in the screening of NCP. In the future, the diagnostic criteria of NCP must be redefined in children.

A high glucose concentration stimulates the expression of monocyte chemotactic peptide 1 in human mesangial cells

The mechanism of glomerular infiltration of monocytes remains unknown in diabetic nephropathy. We examined the effect of a high glucose concentration on monocyte chemotactic peptide 1 (MCP-1) expression in human mesangial cells (MCs) by using enzyme-linked immunosorbent assay and reverse transcription coupled with polymerase chain reaction (PCR). More than a 50% increase in the MCP-1 protein production was observed in MCs cultured in high-glucose medium (450 mg/dl) as compared to normal glucose (100 mg/dl; 1,496 +/- 75 vs. 966 +/- 15 pg/ml after 24 h, 1,910 +/- 93 vs. 1,250 +/- 55 pg/ml after 48 h). Semiquantitative PCR showed that phorbol myristate acetate (100 nM) increased the ratio of PCR products for MCP-1 to housekeeping gene glyceraldehyde-3-phosphate dehydrogenase on densitometric results at 24 h by 2.7-fold, which was prevented by calphostin C (200 nM) pretreatment. High glucose increased the ratio by 3-fold as compared to normal glucose at 24 h (0.72 +/- 0.11 vs. 0.24 +/- 0.01). This was also suppressed by calphostin C pretreatment. These findings demonstrate that high glucose can directly increase MCP-1 expression in MCs, which may contribute to monocyte infiltration in diabetic nephropathy, and this is regulated by protein kinase C.

Morphologic change of the internal elastic lamina in Buerger's disease

Morphologic features and pathogenesis of arterial changes occurring in Buerger's disease (thromboangiitis obliterans) are still controversial. This study describes histopathologic features of medium sized arteries from patients with Buerger's disease, particularly of the internal elastic lamina in relation to the immunologic mechanism of the injury. Seventeen segments of occluded arteries (femoral or popliteal arteries) from 17 patients with Buerger's disease were analyzed by histopathological and immunohistochemical methods. The most characteristic features were total luminal obliteration, together with a varying degree of recanalization and deposition of hemosiderin pigments. Detailed analysis, however, showed marked undulation and multiplication of the internal elastic lamina (100%) associated with basophilic degeneration and delicate linear calcification (47%). Lymphocytic infiltration along the internal elastic lamina was seen in 71% and was associated with localized edema. Lymphocytes along the lamina were consistently positive for T cell marker. Mild to moderate fibrosis was present at the media in 24%. Adventitial changes included mild, nonspecific and irregular fibrosis seen in 53%. Immunologic injury to the internal elastic lamina associated with T-lymphocytic infiltration might be the initial morphogenetic mechanism of the thrombotic occlusion and organization of medium-sized arteries in Buerger's disease.

Ventromedial hypothalamic mediation of photoperiodic gonadal responses in male Syrian hamsters

Short day lengths induce testicular regression in seasonally breeding Syrian hamsters. To test whether the ventromedial hypothalamus is necessary to maintain reproductive quiescence once testicular regression has been achieved, photoregressed male hamsters were subjected to lesions of the ventromedial hypothalamus (VMHx), pinealectomy (Pinx), or sham operation (Sham). VMHx hamsters underwent accelerated gonadal recrudescence compared to Pinx and Sham hamsters. Recovery of prolactin concentrations (PRL) to values characteristic of long-day hamsters was hastened in the VMHx animals compared to Sham hamsters. Concentrations of follicle stimulating hormone (FSH) increased prematurely in both the VMHx and Pinx animals, beginning a few weeks after surgery. By the time the gonads had undergone recrudescence and the hamsters were refractory to melatonin, PRL and FSH concentrations had returned to baseline long-day values in all groups; there was no evidence of hypersecretion of either hormone in any of the animals with lesions. Melatonin concentrations of VMHx hamsters did not differ from those of sham-operated animals, but because only a single determination was made, it remains possible that VMH damage altered the duration of nightly melatonin secretion. An intact VMH appears to be essential for the continued maintenance of reproductive suppression induced by exposure to short day lengths; these and earlier findings suggest that the VMH-dorsomedial hypothalamic complex mediates regression of the reproductive apparatus during decreasing day lengths of late summer and early autumn and also is necessary to sustain regression during the winter months.

Up-regulation of interleukin-4 and CD23/FcepsilonRII in minimal change nephrotic syndrome

Although the pathogenesis of childhood minimal change nephrotic syndrome (MCNS) has not been clearly defined, the current hypothesis favors an involvement of T cell dysfunction. The symptom onset and the relapse of MCNS are frequently associated with allergy and increased IgE levels in sera. Since a T cell-derived cytokine interleukin-4 (IL-4) plays a key role in the regulation of IgE production and allergic response, we investigated the role of IL-4 in the pathophysiology of MCNS. Using fluorescence-activated cell scanning we observed a significantly higher expression of CD23, the type II IgE receptor (FcepsilonRII), on fresh B cells from active MCNS patients (n=22) compared with age-matched healthy normal controls (n=12). The upregulation of CD23 correlates with greater IL-4 activity in the culture supernatant of MCNS peripheral blood lymphocytes (PBLs) than normal PBLs stimulated by mitogens, as assessed by the CD23-inducing effect of the PBL supernatant on tonsillar B cells. Furthermore, Northern blot and reverse transcription-based polymerase chain reaction analysis have revealed significantly elevated levels of IL-4 mRNAs both in mitogen-stimulated and unstimulated MCNS PBLs, compared with healthy normals or disease controls with other renal disorders. Together these results strongly suggest that the upregulation of IL-4 in T cells may be part of the T cell dysfunction involved in MCNS.

Circulating factors in sera or peripheral blood mononuclear cells in patients with membranous nephropathy or diabetic nephropathy

In order to investigate the status of some circulating factors in nephrotic syndrome, we examined the secretion of monocyte chemotactic peptide (MCP)-1, tumor necrosis factor (TNF) alpha or fibronectin in sera or by peripheral blood mononuclear cells (PBMC) from patients with membranous nephropathy (MN), diabetic nephropathy (DN) or minimal change disease (MCD). Also the effects of PBMC or sera on human mesangial cells (MC) were evaluated. Serum TNF alpha levels were higher in patients with MN than in controls, but PBMC exhibited no differences in TNF alpha production between patients and controls. Serum fibronectin levels were higher in patients with MN than in controls. PBMC from diabetic patients with or without nephropathy produced more MCP-1 than cells from controls. When MC were cultured with PBMC supernatants from patients, TNF alpha levels in PBMC supernatants correlated with production of MCP-1 or fibronectin by MC. PBMC supernatants obtained from patients with MCD and MN decreased MCP-1 production by MC, but did not affect thymidine incorporation or fibronectin production by MC. Sera obtained from patients with DN and MCD reduced thymidine incorporation in MC. In summary, serum TNF alpha or fibronectin levels were increased in patients with MN that is known to progress to renal failure. MCP-1 Production was increased by PBMC obtained from diabetic patients with or without nephropathy. Also TNF alpha production by PBMC in individual patients may affect the pathophysiology of their MC.

Effects of mixed leukocyte reaction, hydrocortisone and cyclosporine on expression of leukocyte adhesion molecules by endothelial and mesangial cells

We investigated the effects of mixed leukocyte reaction (MLR), hydrocortisone (HC) and cyclosporine A (CsA) on the expression of leukocyte adhesion molecules on the mesangial (MC) and endothelial cells (EnC). Cell surface enzyme immunoassay showed that INFnu, IL-1beta, or TNF alpha stimulated expression of ICAM-1, or VCAM-1 on MC after 24 hours. Flow cytometric analysis demonstrated that MLR supernatant induced a marked increase in mean fluorescence of or % of cells highly expressing intercellular adhesion molecule(ICAM)-1 or vascular cell adhesion molecule (VCAM)-1 on both cells after 24 hours (p<0.001). HC treatment(300 ng/ml) during MLR effectively inhibited MLR-induced upregulation of ICAM-1 and VCAM-1 on both cells (p<0.005). When MLR supernatant with HC was added to adhesion molecule assay, there was no inhibitory effect of HC on VCAM-1. CsA treatment (500 ng/ml) during MLR caused a modest decrease in upregulation of VCAM-1 on EnC (p<0.05), but had no effects on ICAM-1 on both cells. CsA directly decreased expression of VCAM-1 on MC. In conclusion, alloreactive lymphocytes and monocytes upregulate the expression of VCAM-1 and ICAM-1 on target cells probably by the mediation of cytokines. HC effectively prevents MLR-induced upregulation of VCAM-1 and ICAM-1. CsA does not increase the expression of VCAM-1 and ICAM-1.

A case of shunt nephritis

Nephritis associated with a chronically infected ventriculoatrial shunt is known as shunt nephritis. A 6-year-old girl with prior history of a ventriculoatrial shunt presented complaining of fever and gross hematuria. Serum complement levels were decreased and a coagulase-negative S. epidermidis was cultured from her blood. The renal biopsy specimen showed features of membranoproliferative glomerulonephritis type I. Hydrocephalus was so severe that shunt removal was impossible. With antibiotic therapy, clinical symptoms and laboratory findings include complement levels were normalized although microscopic hematuria persisted. To our knowledge, this is the first case of shunt nephritis in Korea. In addition to the case report, a brief review of shunt nephritis has been added.

Studies on the role of interleukin-4 and Fc epsilon RII in the pathogenesis of minimal change nephrotic syndrome

Childhood minimal change nephrotic syndrome (MCNS) has often been associated with allergic symptoms such as urticaria, bronchial asthma, atopic dermatitis, allergic rhinitis and elevated IgE levels and referred to involve immune dysfunction. Fc epsilon RII is known to be involved in IgE production and response. Interleukin-4 is being recognized as a major cytokine up-regulating IgE production. Hence the present study is aimed at investigating the role of interleukin-4 and Fc epsilon RII in the pathogenesis of MCNS. IgE was measured by ELISA. Fc epsilon RII was analyzed by fluorescence activated cell scanner (FAC-scan) by double antibody staining with anti Leu16-FITC and anti Leu20-PE. Soluble IgE receptor was measured by ELISA using anti CD23 antibody (3-5-14). Interleukin-4 activities were measured by CD23 expression on purified human tonsillar B cells. Serum IgE levels were significantly higher in MCNS (1,507 +/- 680 IU/dl) than in normal controls (123 +/- 99.2 IU/dl). A significantly higher expression of membrane Fc epsilon RII was noted for MCNS (41 +/- 12%) than that in normal controls (18 +/- 6.2%) (p < 0.001). Soluble CD23 levels were also significantly higher in MCNS (198 +/- 39.3%) than in normal controls (153 +/- 13.4) (p < 0.01). Interleukin-4 activity in sera of MCNS (12U/ml) was also significantly higher than normal controls (4.5U/ml). These results indicate that increased production of Fc epsilon RII and interleukin-4 may play an important role in the pathogenesis of MCNS.

Correlation between NMR spectral parameters of nucleosides and its implication to the conformation about the glycosyl bond

Analyses of high resolution proton and carbon NMR spectra of a series of guanine nucleosides in DMSO have revealed a near linear correlation between the chemical shift of the H2, atom of the sugar moiety and the vicinal coupling constant 3JC4-H1'. This unexpected result provides evidence that the variations in the glycosyl torsion angle between nucleosides in solution are less that those which have previously been reported in crystals and it is an experimental basis for analyzing the syn and anti populations from chemical shift and coupling constant data.