Expansion of Myeloid-Derived Suppressor Cells Correlates with Renal Progression in Type 2 Diabetic Nephropathy

Type 2 diabetic nephropathy (T2DN) progresses with an increasingly inflammatory milieu, wherein various immune cells are relevant. Herein, we investigated the levels of myeloid-derived suppressor cells (MDSCs) and their clinical implication in patients with T2DN. A total of 91 subjects (T2DN, n=80; healthy, n=11) were recruited and their PBMCs were used for flow cytometric analysis of polymorphonuclear (PMN-) and monocytic (M-) MDSCs, in addition to other immune cell subsets. The risk of renal progression was evaluated according to the quartiles of MDSC levels using the Cox model. The proportion of MDSCs in T2DN patients was higher than in healthy individuals (median, 6.7% vs. 2.5%). PMN-MDSCs accounted for 96% of MDSCs, and 78% of PMN-MDSCs expressed Lox-1. The expansion of PMN-MDSCs was not related to the stage of T2DN or other kidney disease parameters such as glomerular filtration rate and proteinuria. The production of ROS in PMN-MDSCs of patients was higher than in neutrophils of patients or in immune cells of healthy individuals, and this production was augmented under hyperglycemic conditions. The 4th quartile group of PMN-MDSCs had a higher risk of renal progression than the 1st quartile group, irrespective of adjusting for multiple clinical and laboratory variables. In conclusion, PMN-MDSCs are expanded in patients with T2DN, and may represent as an immunological biomarker of renal progression.

Modulation of SOD1 Subcellular Localization by Transfection with Wild- or Mutant-type SOD1 in Primary Neuron and Astrocyte Cultures from ALS Mice

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by selective degeneration of motor neurons. Mutant superoxide dismutase 1 (SOD1) is often found as aggregates in the cytoplasm in motor neurons of various mouse models and familial ALS patients. The interplay between motor neurons and astrocytes is crucial for disease outcome, but the mechanisms underlying this phenomenon remain unknown. In this study, we investigated whether transient transfection with wild-type and mutant-type SOD1 may lead to amplification of mutant SOD1-mediated toxicity in cortical neurons and astrocytes derived from wild-type and mutant-type (human G93A-SOD1) mice. In transgenic mice expressing either wild- or mutant-type SOD1, we found that green fluorescent protein (GFP)-wtSOD1 was present in the cytoplasm and nuclei of wild-type cortical neurons and astrocytes, whereas GFP-mutant SOD1 was mainly cytoplasmic in wild- and mutant-type cortical neurons and astrocytes. These findings indicate that intracellular propagation of misfolding of GFP-wt or mtSOD1 are possible mediators of toxic processes involved in initiating mislocalization and aggregation. Here, we provide evidence that cytoplasmic aggregates induce apoptosis in G93A-SOD1 mouse cortical neurons and astrocytes and that the toxicity of mutant SOD1 in astrocytes is similar to the pathological effects of ALS on neurons in vitro. Collectively, our results indicate that mtSOD1 probably interacts with wtSOD1 via an unknown mechanism to produce augmented toxicity and may influence aggregate formation and apoptosis.

Pattern of Respiratory Deterioration in Sporadic Amyotrophic Lateral Sclerosis According to Onset Lesion by Using Respiratory Function Tests

Most amyotrophic lateral sclerosis (ALS) patients show focal onset of upper and lower motor neuron signs and spread of symptoms to other regions or the other side clinically. Progression patterns of sporadic ALS are unclear. The aim of this study was to evaluate the pattern of respiratory deterioration in sporadic ALS according to the onset site by using respiratory function tests. Study participants included 63 (42 cervical-onset [C-ALS] and 21 lumbosacral-onset [L-ALS]) ALS patients and 31 healthy controls. We compared respiratory function test parameters among the 3 groups. Age was 57.4+/-9.6 (mean+/-SD), 60.8+/-9, and 60.5+/-7 years, and there were 28, 15, and 20 male participants, in the C-ALS, L-ALS, and control groups, respectively. Disease duration did not differ between C-ALS and L-ALS patients. Sniff nasal inspiratory pressure (SNIP) was significantly low in C-ALS patients compared with controls. Maximal expiratory pressure (MEP) and forced vital capacity percent predicted (FVC% predicted) were significantly low in C-ALS and L-ALS patients compared with controls. Maximal inspiratory pressure to maximal expiratory pressure (MIP:MEP) ratio did not differ among the 3 groups. Eighteen C-ALS and 5 L-ALS patients were followed up. DeltaMIP, DeltaMEP, DeltaSNIP, DeltaPEF, and DeltaFVC% predicted were higher in C-ALS than L-ALS patients without statistical significance. Fourteen C-ALS (77.8%) and 3 L-ALS (60%) patients showed a constant MIP:MEP ratio above or below 1 from the first to the last evaluation. Our results suggest that vulnerability of motor neurons in sporadic ALS might follow a topographic gradient.

Cell Death and Immunity

Dying cells interact with living cells and release molecules that can signal to immune system. Based on the morphology of the dying cells, there are three types of cell death, which are apoptotic cell death (Type I), autophagic cell death (Type II) and necrotic cell death (Type III). The immune response is different according to the pathway of cell death as apoptosis or necrosis regulates immune response via caspase activation or cytokine secretion, respectively. Here, we discuss the different modes of cell death and the nature of the immune response elicited by the released molecules from the cell death.

Anti-inflammatory effects of 8-hydroxydeoxyguanosine in LPS-induced microglia activation: suppression of STAT3-mediated intercellular adhesion molecule-1 expression

To elucidate the roles of 8-hydroxydeoxyguanosine (oh8dG), the nucleoside of 8-hydroxyguanine (oh8Gua), we examined the effects of oh8dG upon LPS-induced intercellular adhesion molecule-1 (ICAM-1) expression and the underlying mechanisms in brain microglial cells. We found that oh8dG reduces LPS-induced reactive oxygen species (ROS) production, STAT3 activation, and ICAM-1 expression. oh8dG also suppresses pro-inflammatory cytokines, such as TNF-alpha, IL-6 and IFN-gamma. Overexpression of dominant negative STAT3 completely diminshed STAT3-mediated ICAM-1 transcriptional activity. Chromatin immunoprecipitation studies revealed that oh8dG inhibited recruitment of STAT3 to the ICAM-1 promoter, followed by a decrease in ICAM-1 expression. Using mice lacking a functional Toll-like receptor 4 (TLR4), we demonstrated that, while TLR4+/+ microglia were activated by LPS, TLR4-/-microglia exhibited inactivated STAT3 in response to LPS. Evidently, LPS modulates STAT3-dependent ICAM-1 induction through TLR4-mdiated cellular responses. Oh8dG apparently plays a role in anti-inflammatory actions via suppression of ICAM-1 gene expression by blockade of the TLR4-STAT3 signal cascade in inflammation-enhanced brain microglia. Therefore, oh8dG in the cytosol probably functions as an anti-inflammatory molecule and should be considered as a candidate for development of anti-inflammatory agents.

Increased expression of adhesion molecules on human umbilical vein endothelial cells by Orientia tsutsugamushi infection

Scrub typhus is caused by Orientia tsutsugamushi characterized by fever, headache, lymphadenopathy and eschar formation. Infiltration of inflammatory cells around blood vessels and within the affected organs is known to be pathologic hallmark of the scrub typhus. Recently, expression of adhesion molecules on vascular endothelial cells was implicated as an important pathogenic mechanism in rickettsial disease. This study was performed to examine the expression of adhesion molecules and to investigate its role in the pathogenesis of O. tsutsugamushi infection. The expression of adhesion molecules on human umbilical vein endothelial cells (HUVEC) was measured by flow cytometry and indirect immunofluorescence. Expression of E-selectin, ICAM-1 and VCAM-1 was significantly increased 4 hours after the infection and persisted at least for 24 hours. Expression of those molecules was not induced by killed O. tsutsugamushi. Adhesion of polymorphonuclear cells and mononuclear cells to HUVEC was increased after the infection with O. tsutsugamushi. In conclusion, adhesion molecules are expressed on HUVEC during the infection of live O. tsutsugamushi and those molecules can contribute to the infiltration of inflammatory cells during the infection.

47kDa Protein of Orientia tsutsugamushi Do a Critical Role in Invasion to Eucaryotic Cells by Binding to Cell Surface Heparan Sulfate

No Abstract Available.

Infectivity of Orientia tsutsugamushi to Various Eukaryotic Cells and Their Cellular Invasion Mechanism

Orientia tsutsugamushi is obligate intracellular bacterium that grows within the cytoplasm of the eukaryotic host cells. Therefore capability of the attachment, entry into the host cell and intracellular survival should be critical process for oriential infection. In this study we investigated the cellular invasion mechanism of Orientia tsutsugamushi and the role of transmembrane heparan sulfate proteoglycan, which binds diverse components at the cellular microenvironment and is implicated as host cell receptors for a variety of microbial pathogens. First of all Orientia tsutsugamushi can invade a wide range of nonprofessional phagocytic cells including fibroblast, epithelial cells a#nd endothelial cells of various host species, including B and T lymphocytes. Thus, it was postulated that the attachment of O. tsutsugamushi requires the recognition of ubiquitous surface structures of many kinds of host cells. Treatments with heparan sulfate and heparin inhibited the infection of Orientia tsutsugamushi in dose-dependent manner for L cell, mouse fibroblast, whereas other glycosaminoglycans such as chondroitin sulfate had no effect. Collectively, these findings provide strong evidence that initial interaction with heparan sulfate proteoglycan is required for the oriential invasion into host cells.

Seroepidemiological Survey of Hemorrhagic Fever with Renal Syndrome in Korea , 1994 - 1996

To understand the seroepidemiological patterns of haemorrhagic fever with renal syndrome in Korea, a nation-wide survey collaborated with fourteen clinics was carried out from 1994 to 1996. Sera of 4,547 patients with acute febrile episodes were tested by indirect immunofluorescent antibody test and the seroepidemiological analysis including sex, age, seasonal and regional distributions were performed. According to the results obtained in this study, the epidemiological characteristics of haemorrhagic fever with renal syndrome in Korea were summarized as follows: 1. Seropositive rate of hemorrhagic fever with renal syndrome among the patients with acute febrile episodes was 6.4% by the cut-off point of 1:40. 2. Among the seropositives, male outnumbered female and the ratio of males to females was 2.0:1.0. 3. Seventy six % of the seropositive patients were 21-60 years old. 4. The number of seropositive cases increased from October and reached maximum in December and began to decrease gradually from January. 5. The geographical distribution of the seropositives cover most areas including Cheju province in Korea.