Expression and significance of SIRT6 in human peritoneal dialysis effluents and peritoneal mesothelial cells.

Sirtuin 6 (SIRT6) can inhibit the fibrosis of many organs. However, the relationship between SIRT6 and peritoneal fibrosis (PF) in peritoneal dialysis (PD) remains unclear. We collected 110 PD patients with a duration of PD for more than 3 months and studied the influence of PD duration and history of peritonitis on SIRT6 levels in PD effluents (PDEs). We also analyzed the relationship between SIRT6 levels in PDEs and transforming growth factor beta 1 (TGF-ß1), IL-6, PD duration, peritoneal function, PD ultrafiltration (UF), and glucose exposure. We extracted human peritoneal mesothelial cells (HPMCs) from PDEs and measured the protein and gene expression levels of SIRT6, E-cadherin, vimentin, and TGF-ß1 in these cells. Based on the clinical results, we used human peritoneal mesothelial cells lines (HMrSV5) to observe the changes in SIRT6 levels and mesothelial-to-mesenchymal transition (MMT) after intervention with PD fluid. By overexpressing and knocking down SIRT6 expression, we investigated the effect of SIRT6 expression on E-cadherin, vimentin, and TGF-ß1 expression to elucidate the role of SIRT6 in mesothelial-to-epithelial transition in PMCs. Results: (1) With the extension of PD duration, the influence of infection on SIRT6 levels in PDEs increased. Patients with the PD duration of more than 5 years and a history of peritonitis had the lowest SIRT6 levels. (2) SIRT6 levels in PDEs were negatively correlated with PD duration, total glucose exposure, TGF-ß1, IL-6 levels, and the dialysate-to-plasma ratio of creatinine (Cr4hD/P), but positively correlated with UF. This indicates that SIRT6 has a protective effect on the peritoneum. (3) The short-term group (PD ≤ 1 year) had higher SIRT6 and E-cadherin gene and protein levels than the mid-term group (1 year < PD ≤ 5 years) and long-term group (PD > 5 years) in PMCs, while vimentin and TGF-ß1 levels were lower in the mid-term group and long-term group. Patients with a history of peritonitis had lower SIRT6 and E-cadherin levels than those without such a history. (4) After 4.25% PD fluid intervention for HPMCs, longer intervention time resulted in lower SIRT6 levels. (5) Overexpressing SIRT6 can lead to increased E-cadherin expression and decreased vimentin and TGF-ß1 expression in HPMCs. Knocking down SIRT6 expression resulted in decreased E-cadherin expression and increased vimentin and TGF-ß1 expression in HPMCs. This indicates that SIRT6 expression can inhibit MMT in HPMCs, alleviate PF associated with PD, and have a protective effect on the peritoneum.

Blockage of TIM-3 relieves lupus nephritis by expanding Treg cells and promoting their suppressive capacity in MRL/lpr mice.

T Cell Immunoglobulin and Mucin Containing Protein-3 (TIM-3) is an important immune checkpoint protein that is expressed in Tregs and affects their function. However, the expression and role of TIM-3 in modulating regulatory T cells (Tregs) in lupus nephritis (LN) are still unknown. In this study, we found that the percentage of TIM-3+ cells among spleen lymphocytes, CD4+ T cells and Tregs was higher in MRL/lpr mice than in MpJ mice. TIM-3high CD4+ T cells and TIM-3high Tregs were mainly responsible for the increase. The percentage of Tregs in TIM-3high CD4+ T cells was lower than that in TIM-3low CD4+ T cells, and the expression of CTLA-4 and IL-10 was lower in TIM-3high Tregs than in the TIM-3low Tregs in MRL/lpr mice. Blockade of TIM-3 in vivo significantly increased the Treg population and the expression of CTLA-4 and IL-10 in Tregs, thus relieving the LN symptoms and pathology in MRL/lpr mice. Additionally, bioinformatics analysis indicated that TIM-3 regulates Treg cells in LN mainly through cytokine-cytokine receptor interactions, the PI3K-Akt signaling pathway, the T cell receptor signaling pathway, Th17 cell differentiation and the FoxO signaling pathway. Together, our study has demonstrated that TIM-3 regulates Tregs in LN and that overexpression of TIM-3 in CD4+ T cells and Tregs leads to Treg quantity and quality deficiency in MRL/lpr mice. Blockade of TIM-3 protects against LN by expanding Tregs and enhancing their suppressive capacity. Finally, TIM-3 might be a potential therapeutic target for the treatment of LN.

Rapamycin relieves lupus nephritis by regulating TIM-3 and CD4+CD25+Foxp3+ Treg cells in an MRL/lpr mouse model.

Lupus nephritis (LN) is a severe consequence of systemic lupus erythematosus (SLE) and is an important driver of morbidity and mortality in SLE. Treg cells and TIM-3 play an important role in the pathogenesis of LN. The beneficial effect of rapamycin on LN has been confirmed in both mouse models and patients, but the effect of rapamycin on Treg cells and TIM-3 is not yet completely understood. In this study, rapamycin treatment attenuated proteinuria, histological damage, and renal deposition of C3, and improved renal function. Spleen and renal draining lymph node weight and serum levels of anti-dsDNA antibodies were also improved by rapamycin. Furthermore, the frequency of Treg cells and Treg functional molecules, such as cytotoxic T cell antigen 4 (CTLA-4), interleukin 10 (IL-10), and transforming growth factor ß1 (TGF-ß1), increased significantly after treatment with rapamycin in MRL/lpr mice. We also found that expression of TIM-3 was significantly decreased in CD4+ T cells and Treg cells in mice treated with rapamycin. In summary, the study demonstrated that rapamycin treatment induced preferential expansion of CD4+CD25+Foxp3+ Tregs with increased expression of CTLA-4, IL-10, and TGF-ß1, and decreased TIM-3 expression, thereby ameliorating lupus nephritis in the MRL/lpr mouse model.

Bone marrow inhibition induced by azathioprine in a patient without mutation in the thiopurine S-methyltransferase pathogenic site: A case report.

BACKGROUND: Azathioprine (AZA) and its close analog 6-mercaptopurine are thiopurines widely used in the treatment of patients with cancer, organ transplantation, and autoimmune or inflammatory diseases, including systemic lupus erythematosus. Bone marrow inhibition is a common side effect of AZA, and severe bone marrow inhibition is related to decreased thiopurine S-methyltransferase (TPMT) activity. CASE SUMMARY: We herein report a patient with proliferative lupus nephritis who was using AZA for maintenance therapy, had no common TPMT pathogenic site mutations, and exhibited severe bone marrow inhibition on the 15th day after oral administration. CONCLUSION: This report alerts physicians to the fact that even though the TPMT gene has no common pathogenic site mutation, severe myelosuppression may also occur.

The Nox1/Nox4 inhibitor attenuates acute lung injury induced by ischemia-reperfusion in mice.

Lung ischemia and reperfusion injury (LIRI) were mediated by several processes including over-production of reactive oxygen species (ROS) and inflammatory activation. ROS generated by nicotinamide adenine dinucletide phosphate (NADPH) oxidase (Nox) may play a pivotal role in pathophysiological changes in a range of disease. However, it was poorly understood in LIRI. Thus, the purpose of our study was to explore whether GKT137831, as a special dual inhibitor of Nox1 and 4, could alleviate LIRI in mice model and explore the minimal dose. According to the protocol, this study was divided into two parts. The first part was to determine the minimal dose of Nox1/4 inhibitor in attenuating LIRI via histopathology and apoptosis analysis. Eighteen C57BL/6J male wild-type mice were randomly divided in to sham, 2.5Nox+sham, 5.0Nox+sham, IR, 2.5Nox+IR and 5.0Nox+IR groups. According to the different group, mice were pretreated with corresponding dose of Nox1/4 inhibitors or normal saline. After LIRI, the results showed 5.0mg/kg Nox1/4 inhibitor could be considered as the minimal dose to alleviate injury by decreasing of lung injury score and the number of TUNEL-positive cells. The second part was to further verify the benefit of 5.0mg/kg Nox1/4 inhibitor in lung protective effects. Thirty-seven C57BL/6J male wild-type mice were divided in to sham, IR and 5.0Nox+IR groups randomly. The results showed that expressions of inflammatory, autophagy cytokines were markedly elevated and PH value was declined after LIRI. However, 5.0 mg/kg Nox1/4 inhibitor significantly attenuated cytokine production as reflected by immunohistochemistry, western blotting and Q-PCR analysis. In conclusion, our findings suggested that 5.0mg/kg Nox1/4 inhibitor contributed to protect lung tissue damage after LIRI via the suppression of inflammatory and autophagy activation.

The overexpression of Thioredoxin-1 suppressing inflammation induced by methamphetamine in spleen.

BACKGROUND: Methamphetamine (METH) is an addictive psychostimulant and has been shown to induce oxidative stress and inflammation in various tissues. Thioredoxin-1 (Trx-1) plays the roles in regulating redox and inhibiting inflammation. Whether Trx-1 is involved in METH-induced inflammation is still unknown. METHODS: The present study was designed to investigate inflammatory factors in spleen of wild type and Trx-1 overexpression transgenic mice after METH treatment. RESULTS: We found the mRNA level of Trx-1 was decreased and mRNA level of Trx-1 binding protein-2 (TBP-2) was increased. The mRNA levels of tumor necrosis factor-α (TNF-α), interferon-γ(IFN-γ), interleukin-2 (IL-2), T-bet and signal transducer and activators of transcription 4 (STAT 4) were increased and the mRNA levels of IL-10, GA-TA-binding protein-3 (GATA-3) and STAT 6 were decreased. Overexpression of Trx-1 reversed the above effects induced by METH. CONCLUSION: The present study showed for the first time that Trx-1 overexpression suppressed the inflammation induced by METH.

The induction of thioredoxin-1 by epinephrine withdraws stress via interaction with ß-arrestin-1.

Stress regulates a panel of important physiological functions and disease states. Epinephrine is produced under stresses threaten to homeostasis. Thioredoxin-1(Trx-1) is a redox regulating protein which is induced to resist stresses and related with various diseases. Thus, it is important to examine whether Trx-1 is induced by epinephrine and to understand the underlying molecular mechanisms that Trx-1 modulates epinephrine stress. Here, we show that the expression of Trx-1 was induced by epinephrine via ß-adrenergic receptor/Cyclic AMP/protein kinase A (PKA) signaling pathway in PC12 cells. The down-regulation of Trx-1 by siRNA aggravated accumulation of γ-H2AX and further decreased expression of p53 by epinephrine. Accordingly, Trx-1 overexpression alleviated accumulation of γ-H2AX and restored the expressions of p53 and C/EBP homologous protein (CHOP) in the cortex, hippocampus and thymus of mice. Moreover, Trx-1 overexpression reduced the malondialdehyde concentration by epinephrine. We further explored the mechanism on p53 and γ-H2AX regulated by Trx-1. We found that overexpression of Trx-1 suppressed ß-arrestin-1 expression through interaction with ß-arrestin-1. Consequently, the downregulation of ß-arrestin-1 suppressed the cell viability and the expressions of γ-H2AX and cyclin D1, and increased p53 expression. Taken together, our data suggest that Trx-1/ß-arrestin-1 interaction may represent a novel endogenous mechanism on protecting against stress.

Comparative analysis of the neuroprotective effects of ginsenosides Rg1 and Rb1 extracted from Panax notoginseng against cerebral ischemia.

Panax notoginseng, a traditional Chinese medicine, has been used for thousands of years to treat ischemic patients. More than 20 saponin components have been isolated from P. notoginseng root and identified chemically. However, these different chemical components have different roles. In this study we compared the neuroprotective mechanisms of ginsenosides Rg1, Rb1, Rg1/Rb1, and panax notoginsenoside (PNS) against injuries caused by cerebral ischemia-reperfusion (I/R). Our results show that all of these treatments significantly reduced infarction volume and alleviated neurological deficits caused by cerebral I/R. The increase in malondialdehyde (MDA) concentration was inhibited by these treatments in the hippocampus. The decreased expressions of thioredoxin-1 (Trx-1), copper-zinc superoxide dismutase (SOD-1), protein kinase B (PKB/Akt), and nuclear factor-kappa B (NF-κB) caused by cerebral I/R were restored by these treatments. The expression of heat shock protein 70 (HSP70) was enhanced in the middle cerebral artery occlusion (MCAO) group, as well as in all of the treatment groups. These results suggest that Rg1 and Rb1 have similar roles in protecting the brain from ischemic damage; however, neither Rg1/Rb1 nor PNS have synergistic effects, thus either Rg1 or the Rb1 monomer should be considered as a pharmacological neuroprotective strategy for use in the case of ischemic stroke.

Matrix-assisted laser desorption/ionization time of flight mass spectrometry in the genetic basis of systemic lupus erythematosus and the complicating kidney injury.

BACKGROUND: It is necessary to develop some innovative methods to reveal and discover the novel (SLE)-related protein molecules. In the present study, matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) was employed to detect the differential expression of serum polypeptides in the patients with systemic lupus erythematosus (SLE) presenting with a family history or complicating with kidney injury so as to identify the proteins associated with the genetic factors and kidney injury in SLE. METHODS: The subjects recruited were divided into four groups, that is, a group of SLE patients with both family history and kidney injury, a group of SLE patients with only kidney injury but no family history, a group of SLE patients with neither family history nor kidney injury, and a control group consisting of healthy volunteers. By adopting MALDI-TOF MS analysis, the serum samples obtained from the three groups of SLE patients were examined and compared with those from the control group; the categorized peptide fingerprint profile was established via the biological data collected from the samples. RESULTS: The expression of protein with a m/z of 4207 Da increased significantly in SLE patients; the protein with a m/z of 2658 Da was expressed in all SLE patients; three proteins (with m/z of 1465, 5332, and 5900 Da respectively) were expressed in the SLE patients complicated with kidney injury and the protein with a m/z of 1943 Da was expressed in SLE patients with family history. CONCLUSION: A number of differential proteins were successfully detected and identified through MALDI-TOF MS detection and these proteins may be associated with the genetic basis of SLE and the complicating kidney injury.

Protective effect of low potassium dextran solution on acute kidney injury following acute lung injury induced by oleic acid in piglets.

BACKGROUND: Low potassium dextran (LPD) solution can attenuate acute lung injury (ALI). However, LPD solution for treating acute kidney injury secondary to ALI has not been reported. The present study was performed to examine the renoprotective effect of LPD solution in ALI induced by oleic acid (OA) in piglets. METHODS: Twelve animals that suffered an ALI induced by administration of OA into the right atrium were divided into two groups: the placebo group (n = 6) pretreated with normal saline and the LPD group (n = 6), pretreated with LPD solution. LPD solution was injected intravenously at a dose of 12.5 ml/kg via the auricular vein 1 hour before OA injection. RESULTS: All animals survived the experiments with mild histopathological injury to the kidney. There were no significant differences in mean arterial pressure (MAP), creatinin and renal damage scores between the two groups. Compared with the placebo group, the LPD group had better gas exchange parameters at most of the observation points ((347.0 ± 12.6) mmHg vs. (284.3 ± 11.3) mmHg at 6 hours after ALI, P < 0.01). After 6 hours of treatment with OA, the plasma concentrations of NGAL and interleukin (IL)-6 in both groups increased dramatically compared to baseline ((6.0 ± 0.6) and (2.50 ± 0.08) folds in placebo group; and (2.5 ± 0.5) and (1.40 ± 0.05) folds in LPD group), but the change of both parameters in the LPD group was significantly lower (P < 0.01) than in the placebo group. And 6 hours after ALI the kidney tissue concentration of IL-6 in the LPD group ((165.7 ± 22.5) pg×ml(-1)×g(-1) protein) was significantly lower (P < 0.01) than that in placebo group ((67.2 ± 25.3) pg×ml(-1)×g(-1) protein). CONCLUSION: These findings suggest that pretreatment with LPD solution via systemic administration might attenuate acute kidney injury and the cytokine response of IL-6 in the ALI piglet model induced by OA injection.