Interleukin 12B rs3212227 T > G polymorphism was associated with an increased risk of gastric cardiac adenocarcinoma in a Chinese population

Gastric cardiac adenocarcinoma (GCA) is one of common malignant tumors in the world. Multiple genes that play critical roles in inflammatory pathways probably are associated with GCA risk. We conducted a hospital-based case-control study to evaluate the genetic effects of functional single nucleotide polymorphisms (SNPs): interleukin 9 (IL9) rs31563 C > T, IL9 rs31564 G > T, IL10 rs1800872 T > G, IL12A rs2243115 T > G, IL12B rs3212227 T > G, and IL13 rs1800925 C > T on the development of GCA. Two hundred and forty-three GCA cases and 476 controls were recruited. Their genotypes were determined using a custom-by-design 48-Plex SNPscan kit. IL12B rs3212227 T > G polymorphism was associated with the increased risk of GCA. However, there was no significant association between the other five SNPs and GCA risk. Stratified analyses indicated that the risk of GCA associated with the IL12B rs3212227 T > G polymorphism was evident among female patients and patients who never smoked or consumed alcoholic drinks. These findings indicated that functional polymorphism IL12B rs3212227 T > G might correlate with GCA risk. However, our results were obtained with a limited sample size; the power of our analysis was low. Larger studies are required to confirm the current findings.

Mechanical force-induced specific MicroRNA expression in human periodontal ligament stem cells

It remains unclear how the expression of microRNAs (miRNAs) in human periodontal ligament stem cells (PDLSCs) might respond to mechanical stretch. To investigate specific miRNA expression in stretched PDLSCs, we used a Flexcell® FX-5000™ tension system to achieve external mechanical stimulation. Then, a custom-designed microarray assay was performed to investigate and describe the genome-wide differential expression of miRNAs in normal and stretched PDLSCs. Finally, we implemented integrative miRNA target prediction and network analysis approaches to construct an interaction network of the key miRNAs and their putative targets. We found that stretching induced morphological changes and increased alkaline phosphatase (ALP) activity, runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and bone sialoprotein (BSP) expression in PDLSCs. The microarray data showed that 53 miRNAs were differentially expressed with stretching. With an interaction network, we examined the connections between 10 selected key miRNAs and their putative target genes, which were related to mechanical force. The results from the interaction network provided a basis for postulating the functional roles of miRNAs in PDLSCs.

Albumin impairs renal tubular tight junctions via targeting the NLRP3 inflammasome

Proteinuria is, not only a hallmark of glomerular disease, but also a contributor to kidney injury. However, its pathogenic mechanism is still elusive. In the present study, the effects of albumin on renal tubular tight junctions and the potential molecular mechanisms of those effects were investigated. In mouse proximal tubular cells (mPTCs), albumin treatment resulted in a significant loss of the cellular tight junction proteins zonula occludens-1 (ZO-1) and claudin-1 in a time- and dose-dependent manner, indicating a severe impairment of the tight junctions. On the basis of our previous study showing that albumin stimulated NLRP3 [neuronal apoptosis inhibitor protein, major histocompatibility complex class 2 transcription activator, incompatibility locus protein from Podospora anserina, and telomerase-associated protein (NACHT); leucine-rich repeat (LRR); and pyrin domain (PYD) domains-containing protein 3] inflammasome activation in mPTCs, we pretreated mPTCs with NLRP3 siRNA (siNLRP3) and found that NLRP3 knockdown significantly blocked the downregulation of ZO-1 and claudin-1 induced by albumin. Similarly, in albumin-overloaded wild-type mice, both ZO-1 and claudin-1 were downregulated at the protein and mRNA levels in parallel with the impaired formation of the tight junctions on transmission electron microscopy and the abnormal renal tubular morphology on periodic acid-Schiff staining, which contrasted with the stimulation of NLRP3 in the renal tubules. In contrast, NLRP3 knockout (NLRP3(-/-)) mice preserved normal ZO-1 and claudin-1 expression as well as largely normal tight junctions and tubular morphology. More importantly, deletion of the NLRP3 pathway downstream component caspase-1 similarly blocked the albumin overload-induced downregulation of ZO-1 and claudin-1. Taken together, these findings demonstrated an important role of the albumin-NLRP3 inflammasome axis in mediating the impairment of renal tubular tight junctions and integrity.

Mitochondrial dysfunction confers albumin-induced NLRP3 inflammasome activation and renal tubular injury

Proteinuria is involved in the development of tubular lesions and in the progressive loss of renal function in chronic kidney diseases via uncertain mechanisms. Growing evidence suggests a pathogenic role of mitochondrial dysfunction in chronic kidney diseases. Therefore, the present study aimed to define the roles of mitochondria in proteinuria-induced renal tubular injury and their underlying mechanisms. Using the albumin-overload mouse model, we observed severe tubular structure damage and striking tubular cell apoptosis. Furthermore, tubular epithelial cells displayed a loss of E-cadherin expression and gained expression of α-smooth muscle actin and vimentin, indicating a cellular phenotypic alteration. Strikingly, these albumin overload-induced abnormalities were robustly blocked by a mitochondrial SOD2 mimic, Mn(III) tetrakis (4-benzoic acid)porphyrin chloride (MnTBAP). In agreement with these results, we observed a marked change in mitochondrial morphology accompanied by mitochondrial cytochrome c release and a copy number reduction of mitochondrial DNA. These alterations were largely reversed by MnTBAP, suggesting a key role for mitochondria-derived oxidative stress in mediating the albumin effect on mitochondrial dysfunction and subsequent tubular injury. Moreover, the NOD-like receptor family, pyrin domain-containing 3 (NLRP3)/caspase-1/cytokine cascade was activated in the kidney by albumin overload and was entirely abolished by MnTBAP. In albumin-treated mouse proximal tubular cells, albumin directly induced ROS production, mitochondrial dysfunction, NLRP3/caspase-1/cytokine cascade activation, cell apoptosis, and cellular phenotypic transition. Similar to our in vivo results, treatment with either MnTBAP or cyclosporin A, a mitochondrial permeability transition pore inhibitor, remarkably attenuated these abnormalities in cells. Taken together, these novel findings demonstrate a potential role for the mitochondrial dysfunction/NLRP3 inflammasome axis in the pathogenesis of proteinuria-induced renal tubular injury.

NLRP3 inflammasome mediates albumin-induced renal tubular injury through impaired mitochondrial function

Proteinuria serves as a direct causative factor of renal tubular cell injury and is highly associated with the progression of chronic kidney disease via uncertain mechanisms. Recently, evidence demonstrated that both NLRP3 inflammasome and mitochondria are involved in the chronic kidney disease progression. The present study was undertaken to examine the role of NLRP3 inflammasome/mitochondria axis in albumin-induced renal tubular injury. In patients with proteinuria, NLRP3 was significantly up-regulated in tubular epithelial cells and was positively correlated with the severity of proteinuria. In agreement with these results, albumin remarkably activated NLRP3 inflammasome in both in vitro renal tubular cells and in vivo kidneys in parallel with significant epithelial cell phenotypic alteration and cell apoptosis. Genetic disruption of NLRP3 inflammasome remarkably attenuated albumin-induced cell apoptosis and phenotypic changes under both in vitro and in vivo conditions. In addition, albumin treatment resulted in a significant mitochondrial abnormality as evidenced by the impaired function and morphology, which was markedly reversed by invalidation of NLRP3/caspase-1 signaling pathway. Interestingly, protection of mitochondria function by Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP) or cyclosporin A (CsA) robustly attenuated albumin-induced injury in mouse proximal tubular cells. Collectively, these findings demonstrated a pathogenic role of NLRP3 inflammasome/caspase-1/mitochondria axis in mediating albumin-induced renal tubular injury. The discovery of this novel axis provides some potential targets for the treatment of proteinuria-associated renal injury.

Dysfunction of the PGC-1α-mitochondria axis confers adriamycin-induced podocyte injury

Adriamycin (ADR)-induced nephropathy in animals is an experimental analog of human focal segmental glomerulosclerosis, which presents as severe podocyte injury and massive proteinuria and has a poorly understood mechanism. The present study was designed to test the hypothesis that the peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α-mitochondria axis is involved in ADR-induced podocyte injury. Using MPC5 immortalized mouse podocytes, ADR dose dependently induced downregulation of nephrin and podocin, cell apoptosis, and mitochondrial dysfunction based on the increase in mitochondrial ROS production, decrease in mitochondrial DNA copy number, and reduction of mitochondrial membrane potential and ATP content. Moreover, ADR treatment also remarkably reduced the expression of PGC-1α, an important regulator of mitochondrial biogenesis and function, in podocytes. Strikingly, PGC-1α overexpression markedly attenuated mitochondrial dysfunction, the reduction of nephrin and podocin, and the apoptotic response in podocytes after ADR treatment. Moreover, downregulation of PGC-1α and mitochondria disruption in podocytes were also observed in rat kidneys with ADR administration, suggesting that the PGC-1α-mitochondria axis is relevant to in vivo ADR-induced podocyte damage. Taken together, these novel findings suggest that dysfunction of the PGC-1α-mitochondria axis is highly involved in ADR-induced podocyte injury. Targeting PGC-1α may be a novel strategy for the treatment of ADR nephropathy and human focal segmental glomerulosclerosis.

MRI evaluation of BBB disruption after adjuvant AcSDKP treatment of stroke with tPA in rat

The primary limitation of thrombolytic treatment of ischemic stroke with tissue plasminogen activator (tPA) is the hemorrhagic risk. We tested AcSDKP (N-acetyl-seryl-aspartyl-lysyl-proline), as an auxiliary therapeutic agent, to reduce blood-brain barrier (BBB) disruption in a combination tPA thrombolytic treatment of stroke. Wistar rats subjected to embolic stroke were randomly assigned to either the tPA monotherapy group (n=9) or combination of tPA and AcSDKP treatment group (n=9) initiated at 4 h after ischemia. Magnetic resonance imaging (MRI) measurements were performed before and after the treatments. Immunohistochemical staining and measurements were performed to confirm MRI findings. Longitudinal MRI permeability measurements with gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) demonstrated that combination treatment of acute embolic stroke with AcSDKP and tPA significantly reduced BBB leakage, compared to tPA monotherapy, at 3 and 6 days (18.3±9.8 mm3 vs. 65.0±21.0 mm3, p<0.001) after the onset of stroke, although BBB leakage was comparable between the two groups prior to the treatments (6.8±4.4 mm3 vs. 4.3±3.3 mm3, p>0.18). The substantial reduction of BBB leakage observed in the combination treatment group was closely associated with reduced ischemic lesions measured by T2 maps (113.6±24.9 mm3 vs. 188.1±60.8 mm3, p<0.04 at 6 days). Histopathological analysis of the same population of rats showed that the combination treatment significantly reduced parenchymal fibrin deposition (0.063±0.059 mm2 vs. 0.172±0.103 mm2, p<0.03) and infarct volume (146.7±35.9 mm3 vs. 199.3±60.4 mm3, p<0.05) compared to the tPA monotherapy at 6days after stroke. MRI provides biological insight into the therapeutic benefit of combination treatment of stroke with tPA and AcSDKP 4h after onset, and demonstrates significantly improved cerebrovascular integrity with neuroprotective effects compared with tPA monotherapy.

Activation of ERK1/2 by NADPH oxidase-originated reactive oxygen species mediates uric acid-induced mesangial cell proliferation

Hyperuricemia is associated with kidney complications including glomerulosclerosis and mesangial cell (MC) proliferation by poorly understood mechanisms. The present study investigated the underlying mechanisms that mediate uric acid (UA)-induced MC proliferation. A rat MC line, HBZY-1, was treated with various concentrations of UA in the presence or absence of a specific extracellular-regulated protein kinase 1/2 (ERK1/2) inhibitor (U0126), apocynin. UA dose dependently stimulated MC proliferation as shown by increased DNA synthesis and number of cells in the S and G2 phases in parallel with the upregulation of cyclin A2 and cyclin D1. In addition, UA time dependently promoted MC proliferation and significantly increased phosphorylation of ERK1/2 but not c-Jun NH2-terminal kinase and p38 MAPK in MCs as assessed by immunoblotting. Inhibition of ERK1/2 signaling via U0126 markedly blocked UA-induced MC proliferation. More importantly, UA induced intracellular reactive oxygen species (ROS) production of MCs dose dependently, which was completely blocked by apocynin, a specific NADPH oxidase inhibitor. Toll-like receptor (TLR)2 and TLR4 signaling had no effect on NADPH-derived ROS and UA-induced MC proliferation. Interestingly, pretreatment with apocynin inhibited ERK1/2 activation, the upregulation of cyclin A2 and cyclin D1, and MC proliferation. In conclusion, UA-induced MC proliferation was mediated by NADPH/ROS/ERK1/2 signaling pathway. This novel finding not only reveals the mechanism of UA-induced MC cell proliferation but also provides some potential targets for future treatment of UA-related glomerular injury.

Interleukin 17A rs4711998 A>G polymorphism was associated with a decreased risk of esophageal cancer in a Chinese population

Esophageal cancer is the eighth most common cancer and sixth leading cause of cancer-associated death worldwide. Besides environmental risk factors, genetic factors might play an important role in the esophageal cancer carcinogenesis. We conducted a hospital-based case-control study to evaluate the genetic effects of functional single nucleotide polymorphisms (SNPs) in the interleukin 17A (IL17A) gene on the development of esophageal cancer. A total of 380 esophageal squamous cell carcinoma (ESCC) cases and 380 controls were recruited for this study. The genotypes were determined using a custom-by-design 48-Plex SNPscan Kit. IL17A rs4711998 A>G polymorphism was associated with the decreased risk of ESCC. When the IL17A rs4711998 AA homozygote genotype was used as the reference group, the AG genotype was associated with a significantly decreased risk for ESCC (AG vs. AA: adjusted odds ratio 0.72, 95% confidential interval 0.53-0.98, P = 0.039). However, there was no significant association between the other five SNPs and ESCC risk. Stratified analyses indicated that a significantly decreased risk of ESCC associated with the IL17A rs4711998 A>G polymorphism was evident among younger patients and patients who never smoking or drinking. These findings indicated that functional polymorphism IL17A rs4711998 A>G might contribute to ESCC susceptibility. However, our results were obtained with a limited sample size; the power of our analysis was low. Future larger studies with more rigorous study designs of other ethnic populations are required to confirm current findings.

A familial WT1 mutation associated with incomplete Denys-Drash syndrome

Denys-Drash syndrome (DDS) is a rare disorder characterized by nephropathy, male pseudohermaphroditism, and wilms tumor. Cases are thought to arise sporadically through a de novo mutation in the wilms tumor suppressor gene (WT1), which encodes a zinc finger protein that not only acts as a tumor suppressor but is essential for normal gonadogenesis, nephrogenesis, and development of the urogenital tract. In this report, we describe a family with the well-known missense mutation in exon 9 of the WT1 gene, 1180C>T (R394W), causing incomplete DDS and no symptoms in their father. The proband, a boy with 46, XY karyotype, was born with ambiguous genitalia, penoscrotal hypospadias, and bilateral inguinal hernias. At 2 years of age, he has proteinuria and diffuse mesangial sclerosis, but no wilms tumor has been detected. The elder sister of the proband, at 3 years of age, has normal genitalia, proteinuria, focal mesangial sclerosis but no wilms tumor. The WT1 mutation was detected in both patients, who have suspected DDS, and their father, who is phenotypically normal.

CONCLUSION

This case is unusual in that the 1180C>T mutation, which has been found in approximately 50 % of patients with complete DDS, has been inherited and is causing mild or no symptoms of DDS.

Application of a global reference for fetal-weight and birthweight percentiles in predicting infant mortality

OBJECTIVE

To determine whether the recently published A global reference for fetal-weight and birthweight percentiles (Global Reference) improves small- (SGA), appropriate- (AGA), and large-for-gestational-age (LGA) definitions in predicting infant mortality.

DESIGN

Population-based cohort study.

SETTING

The US Linked Livebirth and Infant Death records between 1995 and 2004.

POPULATION

Singleton births with birthweight >500 g born at 24-41 weeks of gestation.

METHODS

We compared infant mortality rates of SGA, AGA, and LGA infants classified by three different references: the Global Reference; a commonly used birthweight reference; and Hadlock's ultrasound reference.

MAIN OUTCOME MEASURES

Infant mortality rates.

RESULTS

Among 33 997 719 eligible liveborn singleton births, 25% of preterm and 9% of term infants were classified differently for SGA, AGA, and LGA by the Global Reference and the birthweight reference. The Global Reference indicated higher mortality rates in preterm SGA and preterm LGA infants than the birthweight reference. The mortality rate was considerably higher in infants classified as preterm SGA by the Global Reference but not by the birthweight reference, compared with the corresponding infants classified by the birthweight reference but not by the Global Reference (105.7 versus 12.9 per 1000, RR 8.17, 95% CI 7.38-9.06). Yet, the differences in mortality rates were much smaller in term infants than in preterm infants. Black infants had a particularly higher mortality rate than other races in AGA and LGA preterm and term infants.

CONCLUSIONS

In respect to the commonly used birthweight reference, the Global Reference increases the identification of infant deaths by improved classification of abnormal newborn size at birth, and these advantages were more obvious in preterm than in term infants.

Herpes simplex virus type 2 incidence and associated risk factors among female sex workers in a high HIV-prevalence area of China

Herpes simplex virus type 2 (HSV-2) can contribute to the spread of HIV. From March 2006 to November 2009, female sex workers (FSWs) in Yunnan, China were recruited into an open cohort study to determine incidence and risk factors for HSV-2 acquisition. Participants were interviewed and tested for HSV-2 and other sexually transmitted infections (STIs) every six months. A multivariate Cox proportional hazards regression model with time-dependent variables was used to measure associations with HSV-2 acquisition. In 3.5 years, 83 incident cases of HSV-2 infection were diagnosed, yielding an overall incidence of 21.9 per 100 person years (PY) (95% confidence interval [CI], 17.8-26.3). Working in higher risk commercial sex venues, current Neisseria gonorrhoeae infection, age of sexual debut <18 years and lack of a regular sex partner were independent factors associated with HSV-2 acquisition. The high incidence of HSV-2 suggests that prevention methods for HIV/STI control are urgently needed.

Mitochondrial dysfunction is an early event in aldosterone-induced podocyte injury

We previously showed that mitochondrial dysfunction (MtD) is involved in an aldosterone (Aldo)-induced podocyte injury. Here, the potential role of MtD in the initiation of podocyte damage was investigated. We detected the dynamic changes of urinary protein, urinary F2-isoprostane and renal malondialdehyde levels, kidney ultrastructure morphology, mitochondrial DNA (mtDNA) copy number, mitochondrial membrane potential (ΔΨm), and nephrin and podocin expressions in Aldo-infused mice. Aldo infusion first induced renal oxidative stress, as evidenced by increased levels of urinary F2-isoprostane and renal malondialdehyde, and MtD, as demonstrated by reduced mtDNA, ΔΨm, and ATP production. Later, at 5 days after Aldo infusion, proteinuria and podocyte injury began to appear. In cultured podocytes, Aldo or hydrogen peroxide (H2O2) induced MtD after 2-8 h of treatment, whereas the podocyte damage, as shown by decreased nephrin and podocin expressions, occurred later after 12 h of treatment. Thus Aldo treatment both in vitro and in vivo indicated that MtD occurred before podocyte damage. Additionally, MtDNA depletion by ethidium bromide or mitochondrial transcription factor A (TFAM) RNAi induced MtD, further promoting podocyte damage. TFAM expression was found to be reduced in Aldo-infused mice and Aldo-treated podocytes. Adenoviral vector-mediated overexpression of TFAM prevented Aldo-induced MtD and protected against podocyte injury. Together, these findings support MtD as an early event in podocyte injury, and manipulation of TFAM may be a novel strategy for treatment of glomerular diseases such as podocytopathy.

Production of S-acetoin from diacetyl by Escherichia coli transformant cells that express the diacetyl reductase gene of Paenibacillus polymyxa ZJ-9

S-acetoin (S-AC) is an important four-carbon chiral compound that has unique industrial applications in the asymmetric synthesis of valuable chiral specialty chemicals. However, previous studies showed that the usually low yield and optical purity of S-AC as well as the very high substrate cost have hindered the application of this compound. In the current work, a gene encoding diacetyl reductase (DAR) from a Paenibacillus polymyxa strain ZJ-9 was cloned and expressed in Escherichia coli. Whole cells of the recombinant E. coli were used to produce S-AC from diacetyl (DA). Under optimal conditions, S-AC with high optical purity (purity >99·9%) was obtained with a yield of 13·5 ± 0·24 and 39·4 ± 0·38 g l(-1) under batch and fed-batch culture conditions, respectively. This process featured the biotransformation of DA into S-AC using whole cells of engineered E. coli. The result is a considerable increase in the yield and optical purity of S-AC, which in turn facilitated the practical application of the compound.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrated a highly efficient new method to produce S-acetoin with higher than 99·9% optical purity from diacetyl using whole cells of engineered Escherichia coli. It will therefore decrease the production cost of S-acetoin and highlight its application in asymmetric synthesis of highly valuable chiral compounds.