Serum markers of apoptosis in the early period of heart transplantation

Elevated soluble death receptor 5 can predict poor prognosis in patients with acute respiratory distress syndrome

BACKGROUND

: The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its receptor, death receptor 5 (DR5), participate in pulmonary cell apoptosis. This study aimed to investigate the clinical value of soluble DR5 and TRAIL for prognosis assessment in acute respiratory distress syndrome (ARDS).

RESEARCH DESIGN AND METHODS

: Serum and bronchoalveolar lavage fluid (BALF) samples were collected from ARDS patients and controls. Patients were followed-up until death or discharge. Soluble DR5, TRAIL, TNF-α, soluble receptor for advanced glycation end-products (sRAGE), and albumin levels were measured using the Magnetic Luminex or enzyme-linked immunosorbent assays. Data were analyzed according to their distribution and statistical purpose.

RESULTS

: Serum and BALF DR5 levels were elevated in patients with ARDS; TRAIL elevation and reduction was observed in BALF and serum, respectively. Serum DR5 was higher in non-survivors compared to survivors. Serum DR5 was positively correlated with serum TNF-α and critical illness scores and negatively correlated with serum TRAIL. Serum and BALF DR5 was positively correlated with the alveolar epithelial cell damage (sRAGE) and lung fluid leakage indicators. Serum DR5 exhibited potential for predicting mortality in patients with ARDS.

CONCLUSIONS

: Serum soluble DR5 elevation, a valuable prognosis predictor in ARDS, may be associated with alveolar epithelial cell apoptosis.

Effluent decoy receptor 2 as a novel biomarker of peritoneal fibrosis in peritoneal dialysis patients

BACKGROUND

Peritoneal fibrosis (PF) is a common complication of peritoneal dialysis (PD), but a specific and sensitive biomarker for PF is lacking. The present study aimed to determine the use of effluent decoy receptor 2 (eDcR2) as a biomarker for PF in PD patients.

METHODS

PD patients (n = 248) were recruited, and peritoneal specimens were collected at PD initiation (n = 30) and cessation (n = 33). Enzyme-linked immunoassay was used to measure eDcR2 and the eDcR2 appearance rate (eDcR2-AR) was calculated. The levels of DcR2 mRNA and protein were determined. The correlation of eDcR2 level with peritoneal function, histological parameters and DcR2 expression were analysed. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic performance of eDcR2 for PF, which was defined as a submesothelial thickness 150 µm or more. Co-localisation of DcR2 with a mesothelial marker, fibroblast markers and fibrotic markers were determined.

RESULTS

The eDcR2-AR level correlated with PD duration, D/P Cr values, peritoneal Kt/V and peritoneal injury scores, especially submesothelial thickness (r = 0.638, p < 0.001). DcR2 was primarily expressed in peritoneal fibroblasts, and co-localised with α-SMA, vimentin, collagen I and fibronectin, but not with E-cadherin. Peritoneal DcR2 expression had a positive correlation with eDcR2-AR. ROC analysis indicated eDcR2 had an area under the curve of 0.907 for detection of PF (sensitivity: 78.6%, specificity: 100%) and the best cut-off value was 392.5 pg/min.

CONCLUSION

The eDcR2-AR level is a potential biomarker for assessing PF in PD patients. Effluent DcR2 was mainly derived from peritoneal fibroblasts and DcR2-positive cells may accelerate PF, suggesting that it may be a potential therapeutic target.

Targeting POLE2 Creates a Novel Vulnerability in Renal Cell Carcinoma via Modulating Stanniocalcin 1

Objective

The aim of this study is to investigate the biological functions and the underlying mechanisms of DNA polymerase epsilon subunit 2 (POLE2) in renal cell carcinoma (RCC).

Methods

The datasets of POLE2 expression in The Cancer Genome Atlas Kidney Clear Cell Carcinoma (TCGA-KIRC) and International Cancer Genome Consortium (ICGC) databases was selected and the correlation between POLE2 and various clinicopathological parameters was analyzed. The POLE2 expression in RCC tissues was examined by immunohistochemistry. The POLE2 knockdown cell lines were constructed. In vitro and in vivo experiments were carried out to investigate the function of POLE2 on cellular biology of RCC, including cell viability assay, clone formation assay, flow cytometry, wound-healing assay, Transwell assay, qRT-PCR, Western blot, etc. Besides, microarray, co-immunoprecipitation, rescue experiment, and Western blot were used to investigate the molecular mechanisms underlying the functions of POLE2.

Results

POLE2 was overexpressed in RCC tissues, and high expression of POLE2 was correlated with poor prognosis of RCC. Furthermore, knockdown of POLE2 significantly inhibited cell proliferation, migration, and facilitated apoptosis in vitro. In vivo experiments revealed that POLE2 attenuated RCC tumorigenesis and tumor growth. we also illuminated that stanniocalcin 1 (STC1) was a downstream gene of POLE2, which promoted the occurrence and development of RCC. Besides, knockdown of POLE2 significantly upregulated the expression levels of Bad and p21 while the expression levels of HSP70, IGF-I, IGF-II, survivin, and sTNF-R1 were significantly downregulated. Western blot analysis also showed that knockdown of POLE2 inhibited the expression levels of Cancer-related pathway proteins including p-Akt, CCND1, MAPK9, and PIK3CA.

Conclusion

Knockdown of POLE2 attenuates RCC cells proliferation and migration by regulating STC1, suggesting that POLE2-STC1 may become a potential target for RCC therapy.

POLE2 knockdown reduce tumorigenesis in esophageal squamous cells

Background

Esophageal squamous cell carcinoma (ESCC) is one of the most frequent malignant tumors originated from digestive system around the world and the treatment was limited by the unclear mechanism. DNA polymerase epsilon 2, accessory subunit (POLE2) is involved in DNA replication, repair, and cell cycle control, whose association with ESCC is still not clear.

Methods

In this study, the expression level of POLE2 in ESCC tissues was detected by IHC. The POLE2 knockdown cell line was constructed, identified by qPCR and western blot and used for detecting cellular functions and constructing xenotransplantation mice model. MTT Assay, colony formation assay, flow cytometry, wound-healing assay and Transwell assay were used to detected cell proliferation, apoptosis and migration.

Results

We firstly identified that the expression of POLE2 was overexpressed in ESCC. Moreover, the high expression of POLE2 can predict the tumor deterioration and poor prognosis of ESCC patients. Additionally, downregulation of POLE2 was involved in ESCC progression by promoting proliferation, migration, and inhibiting apoptosis in vitro. In vivo studies proved that POLE2 was positively correlated with ESCC tumor formation, which was consistent with the results in vitro. We also illuminated that POLE2 knockdown upregulated pro-apoptotic proteins (Bax, Caspase3, CD40L, FasL, IGFBP-5 and P21) and downregulated anti-apoptotic proteins (CLAP-2, IGF-I and sTNF-R2). In addition, POLE2 was involved in ESCC via targeting PI3K/Akt, Cyclin D1 signaling pathway.

Conclusions

Therefore, POLE2 was proved to be involved in the development of ESCC, which may be a potential therapeutic target and bring new breakthroughs in the treatment of ESCC.

DCR2, a Cellular Senescent Molecule, Is a Novel Marker for Assessing Tubulointerstitial Fibrosis in Patients with Immunoglobulin A Nephropathy

BACKGROUND/AIMS

Stress-induced cell senescence, which contributes to cell cycle arrest and is independent of age, plays an important role in chronic kidney disease (CKD) progression. DcR2, as a senescent marker, exclusively expressed in senescent tubular epithelia. The objective of this study was to examine whether urinary DcR2 (uDcR2) could be a potential biomarker for tubulointerstitial fibrosis (TIF) in patients with immunoglobulin A nephropathy (IgAN).

METHODS

This study included 210 IgAN patients and 80 healthy volunteers, with uDcR2 levels measured using enzyme-linked immunosorbent assay. We examined the relationship among uDcR2/Cr levels, renal function, and pathological parameters, using regression analysis to identify risk factors for TIF and the area under the curve (AUC) approach to predict TIF. Renal DcR2 expression was quantified by immunohistochemistry. Co-expression of DcR2 with fibrotic markers (α-smooth muscle actin [α-SMA], collagen III) was analyzed by confocal microscopy.

RESULTS

Levels of uDcR2/Cr were significantly higher in IgAN patients and in those with more severe TIF, compared with healthy controls. Serum DcR2 levels were similar across groups. The proportion of IgAN patients with stages 1-2 CKD and T0 was highest among those with uDcR2/Cr <130 ng/g. In contrast, the majority of those with uDcR2/Cr >201 ng/g had stages 4-5 CKD and T2. Levels of uDcR2/Cr were positively associated with urinary albumin to creatinine ratio (ACR), urinary N-acetyl-β-D-glucosaminidase (uNAG)/Cr, and TIF scores and negatively associated with estimated glomerular filtration rate (eGFR). uDcR2/Cr, uNAG, ACR, and eGFR were independent predictors for TIF, with AUC of 0.907 for uDcR2/Cr. This AUC value was higher than that observed for eGFR, uNAG/Cr, or ACR. The sensitivity and specificity of uDcR2/Cr in predicting TIF were 87.0 and 80.5%, respectively. Moreover, uDcR2/Cr levels were positively associated with the percentage of renal DcR2 expression. Renal DcR2 co-localized with α-SMA and collagen III in the kidneys of IgAN patients.

CONCLUSIONS

Levels of uDcR2/Cr were closely associated with the severity of TIF and renal function parameters. uDcR2/Cr represents a potential biomarker for predicting TIF in IgAN patients.

Urinary DcR2 is a novel biomarker for tubulointerstitial injury in patients with diabetic nephropathy

Tubulointerstitial injury (TII) plays a crucial role in the progression of diabetic nephropathy (DN), but lack of specific and sensitive biomarkers for monitoring TII in DN management. This study is to investigate whether urinary decoy receptor 2 (uDcR2) could serve as a novel noninvasive biomarker for assessing TII in DN. We recruited 311 type 2 diabetics and 139 DN patients who were diagnosed by renal biopsy. uDcR2 levels were measured by ELISA, and renal DcR2 expression was detected immunohistochemically. Associations between uDcR2 and renal DcR2 and renal functional parameters were evaluated. Receiver operating characteristics (ROC) curve analyzed area under the curve (AUC) of uDcR2 for assessing TII. Double staining was undertaken for renal DcR2 with proximal and distal tubular markers; senescent markers p16, p21, and senescence-associated β-galactosidase (SA-β-gal); and fibrotic markers collagen I and IV. We found DcR2 was primarily expressed in renal proximal tubules; uDcR2 levels were elevated per albuminuria stratum and correlated with renal functional parameters in diabetics and were associated with percentage of tubular DcR2 and TII score in DN. The uDcR2 had an AUC of 0.909 for assessing TII in DN by ROC analysis. Almost all tubular DcR2 was coexpressed with p16 and p21, and nearly more than one-half of tubular DcR2 was positive for SA-β-gal, primarily in collagen I- and IV-positive regions of DN. Our results indicate uDcR2 could potentially serve as a novel biomarker for TII and may reflect senescence of renal proximal tubular cells in DN pathogenesis.

The changes of vaccinia related kinase 1 in grafted heart after rat heart transplantation

OBJECTIVE

To assess the expression and significance of vaccinia-related kinase 1 (VRK1) after rat heart transplantation.

MATERIALS AND METHODS

Lewis and Wistar rats weighing 250 to 300 g were used as donors and recipients. Allografts were from Wistar transplanted into Lewis, and isografts were transplanted from Lewis into Lewis. Grafts were harvested at 1, 3, 5, and 7 days after transplantation. We performed Western Blot of heart tissues after cardiac transplantation. To analyze VRK1 express between the isografts and allografts for immunohistochemical staining. At 5th day after heart transplantation use related cytokines VRK1 for immunohistochemical. We used double immunofluorescent staining on transverse cryosections of graft tissues by co-labeling with different markers, including those for VRK1, activate caspase-3, α-actinin, VCAM-1, CD4.

RESULTS

Compared with rare expression in syngeneic Lewis rat hearts, VRK1 protein level in allogeneic hearts were detected at various survival times after heterotopic heart transplantation, which observably expressed on day 5 postoperative. In addition, we examined the expression of activate caspase-3 in allogeneic hearts, which has a similar expression with VRK1. Immunohistochemical and immunofluorescent method displayed that VRK1 was widely expressed in cytoplasm of cardiac tissue and activate caspase-3 was also expressed in cardiomyocytes. However, the VRK1 wasn't express in inflammation.

CONCLUSIONS

The VRK1 expression has increased after heart transplantation in allograft and isograft, and VRK1 may play a significant role in myocardial apoptosis after heterotopic heart transplantation in rats.

Pyruvate kinase isoenzyme M2 expression correlates with survival of cardiomyocytes after allogeneic rat heterotopic heart transplantation

The aim of our study was to assess correlations between PKM2 and the survival of cardiomyocytes after heart transplantation in rat. The PKM2, Bcl-xl, active caspase-3 proteins were detected by western blot, and PKM2 was testified by immunohistochemistry and immunofluorescence. At the same time, active caspase-3, α-actinin, VCAM-1, and CD4 were detected by immunofluorescence. Compared with rare expression in syngeneic Lewis rat hearts, the PKM2 protein level in allogeneic hearts was detected at various survival times after transplantation, which prominently expressed on day five postoperatively. In addition, we examined the expression of Bcl-xl and active caspase-3 in allogeneic hearts, which has a similar expression pattern with PKM2. Immunohistochemical and immunofluorescent methods displayed that PKM2 was widely expressed in cardiac tissue, and active caspase-3 was also expressed in cardiomyocytes. However, the PKM2 was not expressed in T cells and other immune response cells. These results suggested that PKM2 may regulate the survival of cardiomyocytes in acute rejection after heart transplantation in rat.