Alterations of the gut microbiota in the lupus nephritis: a systematic review.

BACKGROUND: Emerging evidence suggests that gut microbiota dysbiosis may play a critical role in the development of lupus nephritis (LN). However, the specific characteristics of the gut microbiota in individuals with LN have not been fully clarified. METHODS: The PubMed, Web of Science, and Embase databases were systematically searched for clinical and animal studies related to the relationship between LN and gut microbiota from inception until October 1, 2023. A semiquantitative analysis was used to assess the changes in gut microbial profiles. RESULTS: A total of 15 clinical studies were selected for analysis, which included 138 LN patients, 441 systemic lupus erythematosus patients, and 1526 healthy controls (HCs). Five different types of LN mouse models were included in 5 animal studies. The alpha diversity was decreased in LN patients compared to HCs. A significant decrease in the Firmicutes/Bacteroidetes (F/B) ratio is considered a hallmark of pathological conditions. Specifically, alterations in the abundance of the phylum Proteobacteria, genera Streptococcus and Lactobacillus, and species Ruminococcus gnavus and Lactobacillus reuteri may play a critical role in the pathogenesis of LN. Remarkably, the gut taxonomic chain Bacteroidetes-Bacteroides-Bacteroides thetaiotaomicron was enriched in LN patients, which could be a crucial characteristic of LN patients. The increased level of interleukin-6, imbalance of regulatory T cells and T helper 17 cells, and decreased level of the intestinal tight junction proteins zonula occludens-1 and claudin-1 also might be related to the pathogenesis of LN. CONCLUSIONS: Specific changes in the abundance of gut microbiota such as decreased F/B ratio, and the level of inflammatory indicators, and markers of intestinal barrier dysfunction may play a crucial role in the pathogenesis of LN. These factors could be effective diagnostic and potential therapeutic targets for LN.

Roles of Twist1 in lipid and glucose metabolism.

The abnormal lipid and glucose metabolisms are linked to the metabolic disorders, tumorigenesis, and fibrotic diseases, which attracts the increasing attention to find out the key molecules involved in the lipid and glucose metabolism as the possible therapeutic targets on these diseases. A transcriptional factor Twist1 has been associated with not only the embryonic development, cancer, and fibrotic diseases, but also the regulation of lipid and glucose metabolism. In this review, we will discuss the roles and mechanisms of Twist1 in the obesity-associated white adipose tissue inflammation and insulin resistance, brown adipose tissue metabolism, fatty acid oxidation, and glucose metabolism in skeletal muscle to provide a rational perspective to consider Twist1 as a potential treatment target in clinic. Video Abstract.

Alterations of the gut microbiota in patients with immunoglobulin light chain amyloidosis.

Background: Emerging evidence revealed that gut microbial dysbiosis is implicated in the development of plasma cell dyscrasias and amyloid deposition diseases, but no data are available on the relationship between gut microbiota and immunoglobulin light chain (AL) amyloidosis. Methods: To characterize the gut microbiota in patients with AL amyloidosis, we collected fecal samples from patients with AL amyloidosis (n=27) and age-, gender-, and BMI-matched healthy controls (n=27), and conducted 16S rRNA MiSeq sequencing and amplicon sequence variants (ASV)-based analysis. Results: There were significant differences in gut microbial communities between the two groups. At the phylum level, the abundance of Actinobacteriota and Verrucomicrobiota was significantly higher, while Bacteroidota reduced remarkably in patients with AL amyloidosis. At the genus level, 17 genera, including Bifidobacterium, Akkermansia, and Streptococcus were enriched, while only 4 genera including Faecalibacterium, Tyzzerella, Pseudomonas, and Anaerostignum decreased evidently in patients with AL amyloidosis. Notably, 5 optimal ASV-based microbial markers were identified as the diagnostic model of AL amyloidosis and the AUC value of the train set and the test set was 0.8549 (95% CI 0.7310-0.9789) and 0.8025 (95% CI 0.5771-1), respectively. With a median follow-up of 19.0 months, further subgroup analysis also demonstrated some key gut microbial markers were related to disease severity, treatment response, and even prognosis of patients with AL amyloidosis. Conclusions: For the first time, we demonstrated the alterations of gut microbiota in AL amyloidosis and successfully established and validated the microbial-based diagnostic model, which boosted more studies about microbe-based strategies for diagnosis and treatment in patients with AL amyloidosis in the future.

Twist1 downregulation of PGC-1α decreases fatty acid oxidation in tubular epithelial cells, leading to kidney fibrosis.

Rationale: A deficiency of fatty acid oxidation (FAO) is the metabolic hallmark in proximal tubular cells (PTCs) in renal fibrosis owing to utilization of fatty acids by PTCs as the main energy source. Lipid accumulation may promote lipotoxicity-induced pathological injury in renal tissue. However, the molecular mechanism underlying lipotoxicity and renal tubulointerstitial fibrosis (TIF) remains unclear. Twist1 has been identified to play an essential role in fatty acid metabolism. We hypothesized that Twist1 may regulate FAO in PTCs and consequently facilitate lipotoxicity-induced TIF. Methods: We used hypoxia-induced Twist1 overexpression to incite defective mitochondrial FAO in PTCs, and used renal ischemia-reperfusion or unilateral ureteral obstruction to induce renal injury in mice. We used knockout cells, mice of Twist1, and Harmine to determine the role of Twist1 in FAO and TIF. Results: Overexpression of Twist1 downregulates the transcription of PGC-1α and further inhibits the expression of FAO-associated genes, such as PPARα, CPT1 and ACOX1. Consequently, reduced FAO and increased intracellular lipid droplet accumulation in a human PTC line (HK-2), leads to mitochondrial dysfunction, and production of increased profibrogenic factors. Twist1 knockout mice with renal injury had increased expression of PGC-1α, which restored FAO and obstructed progression of TIF. Strikingly, pharmacological inhibition of Twist1 by using Harmine reduced lipid accumulation and restored FAO in vitro and in vivo. Conclusion: Our findings suggest that Twist1-mediated inhibition of FAO in PTCs results in TIF and suggest that Twist1-targeted inhibition could provide a potential strategy for the treatment of renal fibrosis.

Rare complication of cushing's syndrome in the elderly: a case report.

PURPOSE: Cushing's syndrome (CS) is a rare and severe disease caused by sustained hypercortisolism. The clinical manifestations of CS can be atypical in the elderly, and the diagnosis in these patients is often missed. Infectious Purpura Fulminans (PF) is a life-threating, thrombotic form of disseminated intravascular coagulation with high mortality. To our knowledge, PF occurring in a patient with CS has not been reported previously. METHODS: We described an 84-year-old female presented with severe infection, but normal temperature. She suffered from a variety of diseases especially personality change. Physical examination revealed thin skin, general edema, and multiple scattered ecchymosis. Combined with obviously elevated serum cortisol (36.85 ug/dl) and adenoma revealed by adrenal CT scanning, endogenous CS was diagnosed. During hospitalization, the patient developed serious subcutaneous hemorrhage on the right thigh and back. The skin biopsy showed multiple small vessel thrombosis suggesting that the patient developed the rare complication of CS, Purpura Fulminans (PF). RESULTS: Chronic hypercortisolism can cause immune suppression, low-grade inflammation, endothelial damage, and a hypercoagulable state, which together increased susceptibility of PF. Fluid resuscitation, antibiotics, infusion of blood product, and debridement were effective treatment measures when CS complicated with infectious PF. CONCLUSION: Severe subcutaneous hemorrhage due to PF could occur in the patients of CS, especially in the elderly. Clinicians should be alert to the diagnosis of CS in older adults with cognitive decline and personality change.

A comparative study of cyclophosphamide, thalidomide and dexamethasone (CTD) versus bortezomib and dexamethasone (BDex) in light-chain amyloidosis.

BACKGROUND: Cyclophosphamide, thalidomide, and dexamethasone (CTD) or bortezomib and dexamethasone (BDex) show substantial efficacy in patients with amyloid light-chain (AL) amyloidosis, especially in Chinese patients. Currently, both regimens are recommended as primary treatment options for AL amyloidosis, but no comparative study has been reported. METHODS: We retrospectively evaluated the outcomes of 81 AL patients who received CTD (n = 42) or BDex (n = 39) and used Mayo stage 2012 to match 26 pairs of patients. RESULTS: In the whole cohort, the overall hematologic responses were 86% vs 91% in the CTD and BDex groups, including a complete response of 56% vs 71% based on an intention-to-treat (ITT) analysis. One- and 2-year overall survival (OS) was 90.2% and 81.7% with CTD, and 87.6% and 82.7% with BDex. After matching, BDex regimen induced a significantly deeper and more rapid hematologic response over CTD, but no statistically significant difference in OS (ITT analysis, P = 0.24; 6-month landmark analysis, P = 0.48). Cardiac response rates were similar, while there was a trend for higher renal responses in patients treated with BDex (68% vs 44%, P = 0.09). Additionally, BDex was associated with significantly improved survival in patients with advanced disease (Mayo stage III or worse; P = 0.009). Patients treated with BDex reported more episodes of severe hematologic toxicity and diarrhea. CONCLUSIONS: CTD and BDex are effective treatments for Chinese patients with AL amyloidosis, but BDex regimen appears superior to CTD in achieving a more rapid and deeper clonal response, and in improving OS in patients with advanced disease.

A Comparative Study of the Gut Microbiota Associated With Immunoglobulin a Nephropathy and Membranous Nephropathy.

The pathogenesis of immunoglobulin A nephropathy (IgAN) and membranous nephropathy (MN) is characterized by immune dysregulation, which is related to gut dysbiosis. The aim of the study was to compare the gut microbiota of patients with IgAN and MN vs. healthy controls. We used 16S rDNA amplicon sequencing to investigate the bacterial communities of 44 patients with kidney biopsy-proven IgAN, 40 patients with kidney biopsy-proven MN, and 30 matched healthy controls (HC). The abundance of Escherichia-Shigella and Defluviitaleaceae_incertae_sedis were significantly higher in IgAN than in HC, whereas lower abundances were observed for Roseburia, Lachnospiraceae_unclassified, Clostridium_sensu_stricto_1, and Fusobacterium. Furthermore, the abundance of Escherichia-Shigella, Peptostreptococcaceae_incertae_sedis, Streptococcus, and Enterobacteriaceae_unclassified increased, while that of Lachnospira, Lachnospiraceae_unclassified, Clostridium_sensu_stricto_1, and Veillonella decreased in MN. The abundance of Megasphaera and Bilophila was higher, whereas that of Megamonas, Veillonella, Klebsiella, and Streptococcus was lower in patients with IgAN than in those with MN. Analysis of the correlations showed that in the IgAN group, Prevotella was positively correlated, while Klebsiella, Citrobacter, and Fusobacterium were negatively correlated with the level of serum albumin. Positive correlation also existed between Bilophila and Crescents in the Oxford classification of IgAN. In the MN group, negative correlation was observed between Escherichia-Shigella and proteinuria, Bacteroides and Klebsiella showed positive correlation with the MN stage. Patients with IgAN and MN exhibited gut microbial signatures distinct from healthy controls. Our study suggests the potential of gut microbiota as specific biomarker and contributor in the pathogenesis of IgAN and MN.

Hypoxia-induced HE4 in tubular epithelial cells promotes extracellular matrix accumulation and renal fibrosis via NF-κB.

Hypoxia-induced extracellular matrix (ECM) deposition is an important cause of renal fibrosis that is triggered by unknown mechanisms. Human epididymis secretory protein 4 (HE4) is a newly discovered key molecule that causes ECM deposition. We used the unilateral ureteral obstruction (UUO) mouse model to investigate the expression and mechanisms of HE4 in the pathogenesis of renal fibrosis. Results were confirmed in the HK2 cell line and in human donors of kidney tissue with chronic kidney disease. Hypoxia significantly increased HE4 in renal tubular epithelial cells. HE4 overexpression activated the NF-κB pathway through the NF-κB transcription-activating group P65 by phosphorylation and nuclear translocation. NF-κB upregulated tissue inhibitor metalloproteinases 1, which may inhibit ECM degradation through inhibition of matrix metallopeptidase 2 activity. Silencing HE4 inhibited hypoxia-induced ECM deposition and alleviated fibrosis in UUO mice in vivo and blocked NF-κB activation in vitro. Expression of HE4 in the tubulointerstitium was positively correlated with tubulointerstitial fibrosis in tissue samples from patients with chronic kidney disease. Our results suggest that hypoxia induces renal fibrosis by upregulating HE4 and activating the HIF-1α/HE4/NF-κB signaling pathway. Uncovering the molecular mechanisms and function of HE4 overexpression in hypoxia-induced renal fibrosis will provide important insights into understanding renal fibrosis and antifibrotic strategies.

MicroRNA-493 targets STMN-1 and promotes hypoxia-induced epithelial cell cycle arrest in G2/M and renal fibrosis.

Hypoxia plays an important role in the development of renal fibrosis. G2/M arrest in renal tubular cells is an important pathway in the development of chronic kidney disease. It is unknown whether hypoxia leads to renal fibrosis via the regulation of G2/M arrest in renal tubular epithelial cells. For the first time, to our knowledge, we showed that hypoxia induces G2/M arrest in renal tubular cells leading to renal fibrosis, and microRNAs are involved in this regulation. We compared microRNA expression between hypoxia and normoxia in HK2 cells and found microRNA (miR)-493 to be highly expressed at 24 and 48 h after hypoxia. The overexpression of miR-493 reduced the expression of the cell cycle regulator, Stathmin (STMN)-1, and increased the percentage of G2/M phase cells and profibrotic factors in HK2 cells. Targeting STMN-1 with short hairpin RNA produced an effect similar to that of miR-493 overexpression. On contrast, the miR-493 inhibitor reversed these effects in vitro. Consistent with these results, miR-493 sponge adeno-associated virus reduced the expression of profibrotic factors and increased STMN-1 in vivo. In summary, these results suggest that the miR-493-STMN-1 pathway contributes to hypoxia-induced tubular epithelial cell G2/M arrest and renal fibrosis. Abrogating G2/M arrest and blocking the miR-493-STMN-1 pathway will provide further insight for the development of antifibrosis therapy.-Liu, T., Liu, L., Liu, M., Du, R., Dang, Y., Bai, M., Zhang, L., Ma, F., Yang, X., Ning, X., Sun, S. MicroRNA-493 targets STMN-1 and promotes hypoxia-induced epithelial cell cycle arrest In G2/M and renal fibrosis.

Cell cycle-dependent translocation and regulatory mechanism of CacyBP/SIP in gastric cancer cells.

Our previous results showed that calcyclin-binding protein/Siah-1-interacting protein (CacyBP/SIP) inhibits the proliferation and tumorigenicity of gastric cancer; however, the exact mechanism remains unclear, especially from the aspect of cell cycle. The subcellular localization of CacyBP/SIP, Siah-1, and Skp1 in SGC7901 gastric cancer cells was assessed by immunofluorescence after cell cycle synchronization. Levels of CacyBP/SIP, Siah-1, Skp1, ß-catenin, and p-ERK1/2 were analyzed by western blotting. CacyBP/SIP phosphorylation (p-CacyBP/SIP) and the combining capacity of Siah-1 and Skp1 with CacyBP/SIP in nucleoprotein were determined by immunoprecipitation. CacyBP/SIP, Siah-1, and Skp1 were mainly in the cytoplasm in the G1 phase, but translocated to the nucleus during G2. Their expression in total protein was not altered, but elevated in the G2 phase in nucleoprotein. The CacyBP/SIP nucleus translocation of cells transfected with mutant CacyBP/SIP that does not bind S100 (CacyBP-ΔS100) was significantly increased compared with wild-type CacyBP/SIP. In the G2 phase, p-CacyBP/SIP expression and the combining capacity of Siah-1 and Skp1 with CacyBP/SIP were all increased, whereas levels of ß-catenin and p-ERK1/2 reduced, compared with the G1 phase. CacyBP/SIP or CacyBP-ΔS100 overexpression was correlated with constitutively low ß-catenin expression and affected its level through cell cycle. CacyBP/SIP overexpression led to retarded proliferation, G1 arrest, and ß-catenin reduction, which could be abolished by lithium chloride, ß-catenin activator, and further enhanced by the Wnt inhibitor XAV-939. In addition, CacyBP-ΔS100 further suppressed cell proliferation and induced G1 arrest compared with CacyBP/SIP. In conclusion, CacyBP/SIP nuclear localization, dependent on S100 protein, suppresses gastric cancer tumorigenesis through ß-catenin degradation and the dephosphorylation of ERK1/2 during the G2 phase.

The associations of Bmi-1 with progression of glomerular chronic kidney disease
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BACKGROUND: Our previous studies indicated that Bmi-1 plays an important role in hypoxia-induced tubular epithelial-mesenchymal transition and the development of kidney fibrosis in cellular and animal models. However, circulating Bmi-1 levels in human chronic kidney disease (CKD) and their relation to progression remains unknown. MATERIALS AND METHODS: We conducted a post-hoc analysis of a prospective cohort study. The blood samples and clinical data of 230 patients with glomerular CKD and 67 healthy adults were prospectively collected between January 2010 and June 2012. Serum Bmi-1 was measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: CKD patients had significantly higher serum Bmi-1 concentrations than the healthy controls (496.4 (363.1 - 675.4) pg/mL compared with 257.3 (235.4 - 303.8) pg/mL, p < 0.001). Serum Bmi-1 level inversely correlated with the estimated glomerular filtration rate (eGFR) (r = -0.346, p < 0.001). In addition, positive correlations were identified between serum Bmi-1 levels and serum creatinine, blood urea nitrogen, cystatin C concentration, and the severity of tubulointerstitial fibrosis (r = 0.248, p < 0.001; r = 0.245, p < 0.001; r = 0.273, p < 0.001; r = 0.536, p < 0.001, respectively). Kaplan-Meier survival curves showed that a higher serum Bmi-1 level was associated with a shorter duration of renal survival. Cox multivariate analyses further demonstrated that serum Bmi-1 concentration was an independent prognostic factor for CKD patients (HR = 6.48, p < 0.001). CONCLUSION: Our study showed that high circulating Bmi-1 levels were associated with adverse kidney disease outcome, suggesting that Bmi-1 is a novel biomarker for glomerular CKD progression. More data from larger longitudinal studies are required to validate our findings.
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Risk model for deaths and renal replacement therapy dependence in patients with acute kidney injury after cardiac surgery.

OBJECTIVES: Acute kidney injury (AKI) is a serious complication after cardiac surgery and is associated with increased in-hospital deaths. Renal replacement therapy (RRT) is becoming a routine strategy for severe AKI. Our goal was to evaluate the risk factors for death and RRT dependence in patients with AKI after cardiac surgery. METHODS: We included 190 eligible adult patients who had AKI following cardiac surgery and who required RRT at our centre from November 2010 to March 2015. We collected preoperative, intraoperative, postoperative and RRT data for all patients. RESULTS: In this cohort, 87 patients had successful RRT in the hospital, whereas 103 patients had RRT that failed (70 deaths and 33 cases of RRT dependence). The multivariable logistic analysis identified old age [odds ratio (OR): 1.042, 95% confidence interval (CI): 1.012-1.074; P = 0.011], serum uric acid (OR: 1.015, 95% CI: 1.003-1.031; P = 0.024), intraoperative concentrated red blood cell transfusions (OR: 1.144, 95% CI: 1.006-1.312; P = 0.041), postoperative low cardiac output syndrome (OR: 3.107, 95% CI: 1.179-8.190; P = 0.022) and multiple organ failure (OR: 5.786, 95% CI: 2.115-15.832; P = 0.001) as factors associated with a higher risk for RRT failure. The prediction model (-4.3 + 0.002 × preuric acid + 0.10 × concentrated red blood cells + 0.04 × age + 1.12 × [low cardiac output syndrome = 1] + 1.67 × [multiple organ failure = 1]) based on the multivariate analysis had statistically significant different incriminatory power with an area under the curve of 0.786. CONCLUSIONS: The prediction model may serve as a simple, accurate tool for predicting in-hospital RRT failure for patients with AKI following cardiac surgery.

The potential role of CacyBP/SIP in tumorigenesis.

Calcyclin-binding protein/Siah-1-interacting protein (CacyBP/SIP) was initially described as a binding partner of S100A6 in the Ehrlich ascites tumor cells and later as a Siah-1-interacting protein. This 30 kDa protein includes three domains and is involved in cell proliferation, differentiation, cytoskeletal rearrangement, and transcriptional regulation via binding to various proteins. Studies have also shown that the CacyBP/SIP is a critical protein in tumorigenesis. But, its promotion or suppression of cancer progression may depend on the cell type. In this review, the biological characteristics and target proteins of CacyBP/SIP have been described. Moreover, the exact role of CacyBP/SIP in various cancers is discussed.

Egr-1 mediates chronic hypoxia-induced renal interstitial fibrosis via the PKC/ERK pathway.

BACKGROUND: Chronic hypoxia-induced epithelial-to-mesenchymal transition (EMT) is a crucial process in renal fibrogenesis. Egr-1, as a transcription factor, has been proven to be important in promoting EMT. However, whether it functions in hypoxia-induced renal tubular EMT has not been fully elucidated. METHODS: Egr-1 were detected at mRNA and protein levels by qPCR and Western blot analysis respectively after renal epithelial cells were subjected to hypoxia treatment. Meanwhile, EMT phenotype was also observed through identification of relevant EMT-specific markers. siRNA was used to knock down Egr-1 expression and subsequent changes were observed. Specific PKC and MAPK/ERK inhibitors were employed to determine the molecular signaling pathway involved in Egr-1-mediated EMT phenotype. In vivo assays using rat remnant kidney model were used to validate the in vitro results. Furthermore, Egr-1 expression was examined in the samples of CKD patients with the clinical relevance revealed. RESULTS: Hypoxia treatment enhanced the mRNA and protein levels of Egr-1 in HK-2 cells, which was accompanied by a reduced expression of the epithelial marker E-cadherin and an enhanced expression of the mesenchymal marker Fsp-1. Downregulation of Egr-1 with siRNA reversed hypoxia-induced EMT. Using the specific inhibitors to protein kinase C (calphostin C) or MAPK/ERK (PD98059), we identified that hypoxia induced Egr-1 expression through the PKC/ERK pathway. In addition, the upregulation of Egr-1 raised endogenous Snail levels, and the downregulation of Snail inhibited Egr-1-mediated EMT in HK-2 cells. Through in vivo assays using rat remnant kidney and CKD patients' kidney tissues, we found that Egr-1 and Snail were overexpressed in tubular epithelial cells with EMT. CONCLUSION: Egr-1 may be an important regulator of the development of renal tubular EMT induced by hypoxia through the PKC/ERK pathway and the activation of Snail. Targeting Egr-1 expression or activity might be a novel therapeutic strategy to control renal fibrosis.

S100A6 protein negatively regulates CacyBP/SIP-mediated inhibition of gastric cancer cell proliferation and tumorigenesis.

Calcyclin-binding protein (CacyBP/SIP), identified on the basis of its ability to interact with S100 proteins in a calcium-dependent manner, was previously found to inhibit the proliferation and tumorigenesis of gastric cancer cells in our laboratory. Importantly, the effects of S100 proteins on the biological behavior of CacyBP/SIP in gastric cancer remain unclear. Herein, we report the construction of eukaryotic expression vectors for wild-type CacyBP/SIP and a truncated mutant lacking the S100 protein binding domain (CacyBP/SIPΔS100). The expressions of the wild-type and truncated recombinant proteins were demonstrated by transfection of MKN45 gastric cancer cells. Co-immunoprecipitation assays demonstrated interaction between S100A6 and wild-type CacyBP/SIP in MKN45 cells. Removal of the S100 protein binding domain dramatically reduced the affinity of CacyBP/SIP for S100 proteins as indicated by reduced co-immunoprecipitation of S100A6 by CacyBP/SIPΔS100. The MTT assay, FACS assay, clonogenic assay and tumor xenograft experiment were performed to assess the effect of CacyBP/SIP on cell growth and tumorigenesis in vitro and in vivo. Overexpression of CacyBP/SIP inhibited the proliferation and tumorigenesis of MKN45 gastric cancer cells; the proliferation and tumorigenesis rates were even further reduced by the expression of CacyBP/SIPΔS100. We also showed that S100 proteins negatively regulate CacyBP/SIP-mediated inhibition of gastric cancer cell proliferation, through an effect on ß-catenin protein expression and transcriptional activation of Tcf/LEF. Although the underlying mechanism of action requires further investigation, this study provides new insight into the interaction between S100 proteins and CacyBP/SIP, which might enrich our knowledge of S100 proteins and be helpful for our understanding of the development of gastric cancer.

Twist is a new prognostic marker for renal survival in patients with chronic kidney disease.

BACKGROUND/AIMS: Our previous studies indicate that Twist plays important roles in hypoxia-induced tubular epithelial-mesenchymal transition and the development of kidney fibrosis in cellular and animal models. However, the expression and clinical significance of Twist in patients with chronic kidney disease are not clear. METHODS: We analyzed the degree of expression and localization of Twist in renal biopsies from a wide variety of hypoxic kidney diseases and correlated their immunostaining scores with clinical and histologic parameters. In particular, we also retrospectively analyzed whether the degree of expression of Twist in the renal interstitium was correlated with renal survival. RESULTS: Activated Twist was strongly expressed in tubular epithelial cell nuclei from the kidneys of patients with chronic kidney diseases, while little positive staining for Twist was found in the renal tubules of normal kidneys (p = 0.001). Twist protein in the tubulointerstitium was inversely correlated with estimated glomerular filtration rate (eGFR; r = -0.468, p = 0.029) and positively correlated with serum creatinine (r = 0.44, p = 0.045) and the percentage of tubulointerstitial fibrosis (r = 0.551, p = 0.000). Moreover, a high level of Twist was correlated with activation of HIF-1α expression and E-cadherin repression across all disease groups (p = 0.000, p = 0.000, respectively). By multivariate analysis, the experimental data show that the factors influencing renal survival were eGFR [relative risk (RR) 4.39 (95%CI 1.342, 14.393), p = 0.014] and the degree of expression of Twist [RR 3.43 (95% CI 1.098, 10.684), p = 0.034]. CONCLUSIONS: Our results raise the possibility that Twist activation is a common mechanism in the pathophysiology of a wide range of chronic hypoxic renal diseases and that Twist staining in renal biopsy specimens might provide a valuable histologic index of progression.

Human ribosomal protein S13 promotes gastric cancer growth through down-regulating p27(Kip1).

Our previous works revealed that human ribosomal protein S13 (RPS13) was up-regulated in multidrug-resistant gastric cancer cells and overexpression of RPS13 could protect gastric cancer cells from drug-induced apoptosis. The present study was designed to explore the role of RPS13 in tumorigenesis and development of gastric cancer. The expression of RPS13 in gastric cancer tissues and normal gastric mucosa was evaluated by immunohistochemical staining and Western blot analysis. It was found RPS13 was expressed at a higher level in gastric cancer tissues than that in normal gastric mucosa. RPS13 was then genetically overexpressed in gastric cancer cells or knocked down by RNA interference. It was demonstrated that up-regulation of RPS13 accelerated the growth, enhanced in vitro colony forming and soft agar cologenic ability and promoted in vivo tumour formation potential of gastric cancer cells. Meanwhile, down-regulation of RPS13 in gastric cancer cells resulted in complete opposite effects. Moreover, overexpression of RPS13 could promote G1 to S phase transition whereas knocking down of RPS13 led to G1 arrest of gastric cancer cells. It was further demonstrated that RPS13 down-regulated p27(kip1) expression and CDK2 kinase activity but did not change the expression of cyclin D, cyclin E, CDK2, CDK4 and p16(INK4A). Taken together, these data indicate that RPS13 could promote the growth and cell cycle progression of gastric cancer cells at least through inhibiting p27(kip1) expression.

Expression and clinical significance of Notch receptors in human renal cell carcinoma.

AIMS: The pathological roles of Notch receptors in renal cell carcinoma (RCC) are still unclear, although Notch receptors have been shown to have an effect on many malignant tumours. Therefore, in this study, we examined the patterns of expression and clinical significance of Notch receptors in RCC. METHODS: Eighty-four cases of renal cell carcinoma tissues were detected by immunohistochemistry. Eleven paired fresh surgical renal cell carcinoma and adjacent non-neoplastic renal samples were analysed by Western blot and reverse transcriptase polymerase chain reaction. In addition, the expression of Notch receptors in renal cancer cell lines (A498 and 786-O) and human normal kidney tubule epithelial cell lines (HK-2 and HKC) were analysed by Western blot. RESULTS: The expression levels of Notch1 and Notch4 were absent or significantly decreased in renal cell carcinoma tissues compared with the adjacent non-neoplastic tissues [Notch1: 22.6% (19/84) versus 78.7% (59/75); Notch4: 27.4% (23/84) versus 73.3% (55/75); p < 0.05). Moreover, the levels of expression of Notch1 and Notch4 were also markedly down-regulated in human renal cancer cell lines. Notch1 was negatively correlated with tumour stage, while Notch4 expression had no significant association with pathological parameters. The levels of expression of Notch2 and Notch3 were minimally detected in tumours and non-neoplastic tissues. CONCLUSION: Our findings indicated that the expression of Notch receptors was deregulated and Notch signalling might play an important role in the progress of renal cell carcinoma.

Hypoxia-mediated up-regulation of MGr1-Ag/37LRP in gastric cancers occurs via hypoxia-inducible-factor 1-dependent mechanism and contributes to drug resistance.

Our previous study demonstrated hypoxia-inducible factor-1(HIF-1) could prompt multidrug resistance (MDR) phenotype and MGr1-Ag/37LRP, a novel drug-resistance protein was reported by our labortary, associated with multidrug resistance in gastric cancer. Given this association, we hypothesized that MGr1-Ag/37LRP contributed to HIF-1-dependent hypoxia-induced MDR phenotype. Initial experiments revealed that blocking MGr1-Ag/37LRP expression by siRNA in gastric cancer cells effectively reversed multidrug resistance phenotype induced by hypoxia. Subsequent analysis of MGr1-Ag/37LRP mRNA and protein in gastric cancer cells revealed a time-dependent manner increase with hypoxia. While the up-regulation of MGr1-Ag/37LRP was abolished by HIF-1 inhibition with siRNA. Studies using luciferase promoter constructs revealed a significant increase in activity in cells subject to hypoxia and such hypoxia inducibility was lost in cells co-transfected siRNA targeting HIF-1. Analysis of the MGr1-Ag/37LRP promoter revealed several potential binding sites for HIF-1. Electrophoretic mobility shift assay and chromatin immunoprecipitation demonstrated a functional HIF-1 binding site within MGr1-Ag/37LRP gene regulatory sequence located at -16 to -11 relative to the transcriptional initiation point. These observations demonstrate that MGr1-Ag/37LRP is actively engaged by hypoxia and represent a novel HIF-1 target. Such results suggest hypoxia-elicited MGr1-Ag/37LRP expression as a pathway for resistance of gastric cancer to chemotherapeutics.