Inhibition of transcriptional coactivator YAP Impairs the expression and function of transcription factor WT1 in diabetic podocyte injury.

Podocyte injury and loss are hallmarks of diabetic nephropathy (DN). However, the molecular mechanisms underlying these phenomena remain poorly understood. YAP (Yes-associated protein) is an important transcriptional coactivator that binds with various other transcription factors, including the TEAD family members (nuclear effectors of the Hippo pathway), that regulate cell proliferation, differentiation, and apoptosis. The present study found an increase in YAP phosphorylation at S127 of YAP and a reduction of nuclear YAP localization in podocytes of diabetic mouse and human kidneys, suggesting dysregulation of YAP may play a role in diabetic podocyte injury. Tamoxifen-inducible podocyte-specific Yap gene knockout mice (YappodKO) exhibited accelerated and worsened diabetic kidney injury. YAP inactivation decreased transcription factor WT1 expression with subsequent reduction of Tead1 and other well-known targets of WT1 in diabetic podocytes. Thus, our study not only sheds light on the pathophysiological roles of the Hippo pathway in diabetic podocyte injury but may also lead to the development of new therapeutic strategies to prevent and/or treat DN by targeting the Hippo signaling pathway.

Relocation of lower pole renal stones helps improve the stone-free rate during flexible ureteroscopy with a low complication rate.

OBJECTIVE: To compare the efficacy and safety of relocating the lower pole stones to a favorable pole during flexible ureteroscopy with in situ lithotripsy for the treatment of 10-20 mm lower pole stone (LPS). METHODS: This study was a prospective analysis of patient outcomes who underwent an FURS procedure for the treatment of 10-20 mm lower pole renal stones from January 2020 to November 2022. The patients were randomized into a relocation group or in situ group. The LPSs were relocated into a calyx, during lithotripsy in the relocation group was performed, whereas the in situ group underwent FURS without relocation. All the procedures were performed by the same surgeon. The patients' demographic data, stone characteristics, perioperative parameters and outcomes, stone-free rate (SFR), complications, and overall costs were assessed retrospectively. RESULTS: A total of 90 patients were enrolled and analyzed in this study (45 per group) with no significant differences between the two groups in terms of age, gender, BMI, diabetes, hypertension, stone size, number, laterality, composition, and density. The mean operation time, total energy consumption, postoperative stay, and complications were similar between the groups. Both groups had similar SFR at 1 day postoperative follow-up (p = 0.091), while the relocation group achieved significantly higher SFR 3 months later (97.8% vs 84.4%, p = 0.026). The relocation group also had a significantly higher WisQol score than the in situ group (126.98 vs 110.18, p < 0.001). CONCLUSION: A satisfactory SFR with a relatively low complication rate was achieved by the relocation technique during the FURS procedure.

Expression and Function of the Epidermal Growth Factor Receptor in Physiology and Disease.

The epidermal growth factor receptor (EGFR) is the prototypical member of a family of membrane-associated intrinsic tyrosine kinase receptors, the ErbB family. EGFR is activated by multiple ligands, including EGF, transforming growth factor (TGF)-α, HB-EGF, betacellulin, amphiregulin, epiregulin, and epigen. EGFR is expressed in multiple organs and plays important roles in proliferation, survival, and differentiation in both development and normal physiology, as well as in pathophysiological conditions. In addition, EGFR transactivation underlies some important biologic consequences in response to many G protein-coupled receptor (GPCR) agonists. Aberrant EGFR activation is a significant factor in development and progression of multiple cancers, which has led to development of mechanism-based therapies with specific receptor antibodies and tyrosine kinase inhibitors. This review highlights the current knowledge about mechanisms and roles of EGFR in physiology and disease.

CircTENM3 inhibites tumor progression via the miR-558/RUNX3 axis in prostate cancer.

BACKGROUND: Prostate cancer (PCa) is currently acknowledged as the second most widespread cancer among men worldwide. Yet, the lack of dependable diagnostic biomarkers and therapeutic targets has presented considerable hurdles to the progression of prostate cancer treatment. Circular RNAs are implicated in the pathogenesis of numerous diseases, positioning them as promising biomarkers for diverse medical conditions. This study aims to uncover a specific circRNA that could serve as a diagnostic and therapeutic target for detecting and treating PCa. METHODS: The change of circTENM3 expression levels in PCa was detected by qPCR. CCK8 assays, EdU assays, Scratch assay and Transwell migration assay conducted to detect the role of circTENM3 in PCa cells in vitro. RIP assay, RNA-pull down and luciferase reporter assay were performed to explore the mechanism of circTENM3. Gain-of-function analysis was performed to reveal the function of circTENM3 in PCa in vivo. RESULTS: The results revealed that the expression level of circTENM3 was significantly down-regulated in PCa. CircTENM3 overexpression alleviated the progression of PCa in vitro. Mechanistically, circTENM3 enhanced RUNX3 levels via miR-558 sponge. Gain-of-function analysis determined that circTENM3 overexpression could inhibit PCa progression in vitro. CONCLUSIONS: Our research offers profound insights into the protective role played by circTENM3 in PCa. CircTENM3 operates as a sponge for miR-558, thereby triggering the elevation of RUNX3 expression, which subsequently curbs the progression of PCa.

TAZ is important for maintenance of the integrity of podocytes.

The podocyte is an important component of the glomerular filtration barrier, and maintenance of the integrity of its highly specified structure and function is critical for normal kidney function. Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) are two crucial effectors of the Hippo signaling pathway, and recent studies have shown that podocyte-specific YAP deletion causes podocyte apoptosis and the development of focal segmental glomerulosclerosis followed by progressive renal failure. In the present study, we investigated a potential role of the YAP paralog TAZ in podocytes. TAZ was found to be constitutively active in podocytes, and mice with podocyte-specific deletion of TAZ (TazpodKO) developed proteinuria starting at 4 wk of age and had increased podocyte apoptosis. Using primary cultured podocytes or immortalized mouse podocytes from Tazflox/flox mice, we found that TAZ is a transcriptional activator for TEAD-dependent expression of synaptopodin, zonula occludens-1, and zonula occludens-2. This is the first study to determine that TAZ plays an important role in the maintenance of the structure and function of podocytes.NEW & NOTEWORTHY Podocytes play an important role in maintaining the integrity of the structure and function of the kidney. We observed that mice with selective deletion of transcriptional coactivator with PDZ-binding motif (TAZ) in podocytes developed proteinuria. TAZ is constitutively active and critical for expression of synaptopodin, zonula occludens-1, and zonula occludens-2 in podocytes. The findings of this study implicate TAZ as an important mediator of podocyte structural integrity and provide further insights into the role of Hippo-Yes-associated protein/TAZ in podocyte biology.

Nuclear exclusion of YAP exacerbates podocyte apoptosis and disease progression in Adriamycin-induced focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is a chronic glomerular disease with poor clinical outcomes. Podocyte loss via apoptosis is one important mechanism underlying the pathogenesis of FSGS. Recently, Yes-associated-protein (YAP), a key downstream protein in the Hippo pathway, was identified as an activator for multiple gene transcriptional factors in the nucleus to control cell proliferation and apoptosis. To investigate the potential role of YAP in the progression of FSGS, we examined kidney samples from patients with minimal change disease or FSGS and found that increases in podocyte apoptosis is positively correlated with the cytoplasmic distribution of YAP in human FSGS. Utilizing an established mT/mG transgenic mouse model and primary cultured podocytes, we found that YAP was distributed uniformly in nucleus and cytoplasm in the podocytes of control animals. Adriamycin treatment induced gradual nuclear exclusion of YAP with enhanced phospho-YAP/YAP ratio, accompanied by the induction of podocyte apoptosis both in vivo and in vitro. Moreover, we used verteporfin to treat an Adriamycin-induced FSGS mouse model, and found YAP inhibition by verteporfin induced nuclear exclusion of YAP, thus increasing podocyte apoptosis and accelerating disease progression. Therefore, our findings suggest that YAP nuclear distribution and activation in podocytes is an important endogenous anti-apoptotic mechanism during the progression of FSGS.

Identification of key gene modules and pathways of human glioma through coexpression network.

Glioma causes great harm to people worldwide. Systemic coexpression analysis of this disease could be beneficial for the identification and development of new prognostic and predictive markers in the clinical management of glioma. In this study, we extracted data sets from the Gene Expression Omnibus data set by using "glioma" as the keyword. Then, a coexpression module was constructed with the help of Weighted Gene Coexpression Network Analysis software. Besides, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on the genes in these modules. As a result, the critical modules and target genes were identified. Eight coexpression modules were constructed using the 4,000 genes with a high expression value of the total 141 glioma samples. The result of the analysis of the interaction among these modules showed that there was a high scale independence degree among them. The GO and KEGG enrichment analyses showed that there was a significant difference in the enriched terms and degree among these eight modules, and module 5 was identified as the most important module. Besides, the pathways it was enriched in, hsa04510: Focal adhesion and hsa04610: Complement and coagulation cascades, were determined as the most important pathways. In summary, module 5 and the pathways it was enriched in, hsa04510: Focal adhesion and has 04610: Complement and coagulation cascades, have the potential to serve as biomarkers for patients with glioma.

EGF Receptor-Dependent YAP Activation Is Important for Renal Recovery from AKI.

BACKGROUND: Increasing evidence indicates that renal recovery from AKI stems from dedifferentiation and proliferation of surviving tubule epithelial cells. Both EGF receptor (EGFR) and the Hippo signaling pathway are implicated in cell proliferation and differentiation, and previous studies showed that activation of EGFR in renal proximal tubule epithelial cells (RPTCs) plays a critical role in recovery from ischemia-reperfusion injury (IRI). In this study, we explored RPTC activation of Yes-associated protein (YAP) and transcriptional coactivator with PDZ binding motif (TAZ), two key downstream effectors of the Hippo pathway, and their potential involvement in recovery from AKI. METHODS: We used immunofluorescence to examine YAP expression in kidney biopsy samples from patients with clinical AKI and controls (patients with minimal change disease). Studies of RPTC activation of YAP and TAZ used cultured human RPTCs that were exposed to hypoxia-reoxygenation as well as knockout mice (with inducible deletions of Yap, Taz, or both occurring specifically in RPTCs) that were subjected to bilateral IRI. RESULTS: YAP was activated in RPTCs in kidneys from post-AKI patients and post-IRI mouse kidneys. Inhibition of the interaction of YAP and the TEA domain (TEAD) transcription factor complex by verteporfin or conditional deletion of YAP in RPTCs delayed renal functional and structural recovery from IRI, whereas TAZ deletion had no effect. Activation of the EGFR-PI3K-Akt pathway in response to IRI signaled YAP activation, which promoted cell cycle progression. CONCLUSIONS: This study shows that EGFR-PI3K-Akt-dependent YAP activation plays an essential role in mediating epithelial cell regeneration during kidney recovery from AKI.

AZD5153 Inhibits Prostate Cancer Cell Growth in Vitro and in Vivo.

BACKGROUNDS/AIMS: Bromodomain-containing protein 4 (BRD4) overexpression participates in prostate cancer progression by enhancing the transcriptional activity and expression of several key oncogenes. AZD5153 is a novel BRD4 inhibitor. METHODS: Prostate cancer cells were treated with AZD5153. Cell survival was tested by MTT assay and clonogenicity assay. Cell proliferation was tested by [H3] DNA incorporation assay. Cell apoptosis was tested by caspase-3/-9 activity assay, Histone DNA ELISA assay, Annexin V FACS assay and TUNEL staining assay. Cell cycle progression was tested by propidium iodide (PI) FACS assay. Signaling was tested by Western blotting assay. The nude mice PC-3 xenograft model was applied to test AZD5153's activity in vivo. RESULTS: AZD5153 inhibited proliferation and survival of established and primary prostate cancer cells. AZD5153 induced apoptosis activation and cell cycle arrest in prostate cancer cells. AZD5153 was non-cytotoxic to the prostate epithelial cells. AZD5153 downregulated BRD4 targets (cyclin D1, Myc, Bcl-2, FOSL1 and CDK4) in PC-3 and primary prostate cancer cells. Further studies show that AKT could be the primary resistance factor of AZD5153. Pharmacological inhibition or genetic depletion of AKT induced BRD4 downregulation, sensitizing AZD5153-induced cytotoxicity in PC-3 cells. In vivo, AZD5153 oral administration inhibited PC-3 xenograft tumor growth in nude mice. Its anti-tumor activity was further enhanced with co-treatment of the AKT specific inhibitor MK-2206. CONCLUSION: Together, our results indicate a promising therapeutic value of the novel BRD4 inhibitor AZD5153 against prostate cancer cells.

Interaction of the EGF Receptor and the Hippo Pathway in the Diabetic Kidney.

Activation of the EGF receptor (EGFR) or the Hippo signaling pathway can control cell proliferation, apoptosis, and differentiation, and the dysregulation of these pathways can contribute to tumorigenesis. Previous studies showed that activation of EGFR signaling in renal epithelial cells can exacerbate diabetic kidney injury. Moreover, EGFR has been implicated in regulating the Hippo signaling pathway in Drosophila; thus, we examined this potential interaction in mammalian diabetic kidney disease. Yes-associated protein (YAP) is a transcriptional regulator regulated by the Hippo signaling pathway. We found YAP protein expression and phosphorylation were upregulated in diabetic mouse renal proximal tubule epithelial cells, which were inhibited in diabetic proximal tubule EGFR-knockout mice (EGFR(ptKO)) or administration of an EGFR tyrosine kinase inhibitor erlotinib. Furthermore, activation of an EGFR-PI3K-Akt-CREB signaling pathway mediated YAP gene expression and YAP nuclear translocation and interaction with the TEA domain (TEAD) transcription factor complex, which led to upregulated expression of two TEAD-dependent genes, the connective tissue growth factor and amphiregulin genes. In a renal proximal tubule cell line, either pharmacologic or genetic inhibition of EGFR, Akt, or CREB blunted YAP expression in response to high-glucose treatment. Additionally, knocking down YAP expression by specific siRNA inhibited cell proliferation in response to high glucose or exogenous EGF. Therefore, these results link the Hippo pathway to EGFR-mediated renal epithelial injury in diabetes.

Blocking rpS6 Phosphorylation Exacerbates Tsc1 Deletion-Induced Kidney Growth.

The molecular mechanisms underlying renal growth and renal growth-induced nephron damage remain poorly understood. Here, we report that in murine models, deletion of the tuberous sclerosis complex protein 1 (Tsc1) in renal proximal tubules induced strikingly enlarged kidneys, with minimal cystogenesis and occasional microscopic tumorigenesis. Signaling studies revealed hyperphosphorylation of eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and increased phosphorylation of ribosomal protein S6 (rpS6) in activated renal tubules. Notably, knockin of a nonphosphorylatable rpS6 in these Tsc1-mutant mice exacerbated cystogenesis and caused drastic nephron damage and renal fibrosis, leading to kidney failure and a premature death rate of 67% by 9 weeks of age. In contrast, Tsc1 single-mutant mice were all alive and had far fewer renal cysts at this age. Mechanistic studies revealed persistent activation of mammalian target of rapamycin complex 1 (mTORC1) signaling causing hyperphosphorylation and consequent accumulation of 4E-BP1, along with greater cell proliferation, in the renal tubules of Tsc1 and rpS6 double-mutant mice. Furthermore, pharmacologic treatment of Tsc1 single-mutant mice with rapamycin reduced hyperphosphorylation and accumulation of 4E-BP1 but also inhibited phosphorylation of rpS6. Rapamycin also exacerbated cystic and fibrotic lesions and impaired kidney function in these mice, consequently leading to a premature death rate of 40% within 2 weeks of treatment, despite destroying tumors and decreasing kidney size. These findings indicate that Tsc1 prevents aberrant renal growth and tumorigenesis by inhibiting mTORC1 signaling, whereas phosphorylated rpS6 suppresses cystogenesis and fibrosis in Tsc1-deleted kidneys.

EGF receptor deletion in podocytes attenuates diabetic nephropathy.

The generation of reactive oxygen species (ROS), particularly superoxide, by damaged or dysfunctional mitochondria has been postulated to be an initiating event in the development of diabetes complications. The glomerulus is a primary site of diabetic injury, and podocyte injury is a classic hallmark of diabetic glomerular lesions. In streptozotocin-induced type 1 diabetes, podocyte-specific EGF receptor (EGFR) knockout mice (EGFR(podKO)) and their wild-type (WT) littermates had similar levels of hyperglycemia and polyuria, but EGFR(podKO) mice had significantly less albuminuria and less podocyte loss compared with WT diabetic mice. Furthermore, EGFR(podKO) diabetic mice had less TGF-ß1 expression, Smad2/3 phosphorylation, and glomerular fibronectin deposition. Immunoblotting of isolated glomerular lysates revealed that the upregulation of cleaved caspase 3 and downregulation of Bcl2 in WT diabetic mice were attenuated in EGFR(podKO) diabetic mice. Administration of the SOD mimetic mito-tempol or the NADPH oxidase inhibitor apocynin attenuated the upregulation of p-c-Src, p-EGFR, p-ERK1/2, p-Smad2/3, and TGF-ß1 expression and prevented the alteration of cleaved caspase 3 and Bcl2 expression in glomeruli of WT diabetic mice. High-glucose treatment of cultured mouse podocytes induced similar alterations in the production of ROS; phosphorylation of c-Src, EGFR, and Smad2/3; and expression of TGF-ß1, cleaved caspase 3, and Bcl2. These alterations were inhibited by treatment with mito-tempol or apocynin or by inhibiting EGFR expression or activity. Thus, results of our studies utilizing mice with podocyte-specific EGFR deletion demonstrate that EGFR activation has a major role in activating pathways that mediate podocyte injury and loss in diabetic nephropathy.

Phosphorylation of ribosomal protein S6 mediates compensatory renal hypertrophy.

The molecular mechanism underlying renal hypertrophy and progressive nephron damage remains poorly understood. Here we generated congenic ribosomal protein S6 (rpS6) knock-in mice expressing nonphosphorylatable rpS6 and found that uninephrectomy-induced renal hypertrophy was significantly blunted in these knock-in mice. Uninephrectomy-induced increases in cyclin D1 and decreases in cyclin E in the remaining kidney were attenuated in the knock-in mice compared with their wild-type littermates. Uninephrectomy induced rpS6 phosphorylation in the wild-type mice; however, no rpS6 phosphorylation was detected in uninephrectomized or sham-operated knock-in mice. Nonetheless, uninephrectomy stimulated comparable 4E-BP1 phosphorylation in both knock-in and wild-type mice, indicating that mTORC1 was still activated in the knock-in mice. Moreover, the mTORC1 inhibitor rapamycin prevented both rpS6 and 4E-BP1 phosphorylation, significantly blunted uninephrectomy-induced renal hypertrophy in wild-type mice, but did not prevent residual renal hypertrophy despite inhibiting 4E-BP1 phosphorylation in uninephrectomized knock-in mice. Thus, both genetic and pharmacological approaches unequivocally demonstrate that phosphorylated rpS6 is a downstream effector of the mTORC1-S6K1 signaling pathway mediating renal hypertrophy. Hence, rpS6 phosphorylation facilitates the increase in cyclin D1 and decrease in cyclin E1 that underlie the hypertrophic nature of uninephrectomy-induced kidney growth.

Novel κ-opioid receptor agonist MB-1C-OH produces potent analgesia with less depression and sedation.

AIM: To characterize the pharmacological profiles of a novel κ-opioid receptor agonist MB-1C-OH. METHODS: [(3)H]diprenorphine binding and [(35)S]GTPγS binding assays were performed to determine the agonistic properties of MB-1C-OH. Hot plate, tail flick, acetic acid-induced writhing, and formalin tests were conducted in mice to evaluate the antinociceptive actions. Forced swimming and rotarod tests of mice were used to assess the sedation and depression actions. RESULTS: In [(3)H]diprenorphine binding assay, MB-1C-OH did not bind to µ- and δ-opioid receptors at the concentration of 100 µmol/L, but showed a high affinity for κ-opioid receptor (Ki=35 nmol/L). In [(35)S]GTPγS binding assay, the compound had an Emax of 98% and an EC50 of 16.7 nmol/L for κ-opioid receptor. Subcutaneous injection of MB-1C-OH had no effects in both hot plate and tail flick tests, but produced potent antinociception in the acetic acid-induced writhing test (ED50=0.39 mg/kg), which was antagonized by pretreatment with a selective κ-opioid receptor antagonist Nor-BNI. In the formalin test, subcutaneous injection of MB-1C-OH did not affect the flinching behavior in the first phase, but significantly inhibited that in the second phase (ED50=0.87 mg/kg). In addition, the sedation or depression actions of MB-1C-OH were about 3-fold weaker than those of the classical κ agonist (-)U50,488H. CONCLUSION: MB-1C-OH is a novel κ-opioid receptor agonist that produces potent antinociception causing less sedation and depression.

[Pidemiological analysis of pesticide poisoning in hangzhou during 2006-2013].

OBJECTIVE: The purpose of this current investigation was to describe the distribution characteristics of pesticides poisoning in Hangzhou during 2006-2013. METHODS: The registration data of pesticide poisoning in Hangzhou during 2006-2013 were collected from health disserve surveillance information system which was part of China information system for disease control and prevention. The statistical analysis method included Pearson Chi-square test and Cochran-Armitage trend test. RESULTS: There were totally 6232 cases with pesticide poisoning during 2006-2013, of which 414 cases died. The fatality rate of poisoning patients was 6.64%. The pesticides, especially organophosphorus pesticides, were the main poison that caused poisoning, and patients with pesticide poisoning accounted for 80.60% of all the poisoning patient. There was more female patients than male patients among non-productive pesticide poisoning, but on the contrary among productive pesticide poisoning. The incidence of pesticides poisoning had significant increase in the third season. CONCLUSIONS: Occupational pesticide poisoning and non-occupational pesticide poisoning had the different distribution character. Non-occupational pesticide poisoning was the chief reason of pesticide poisoning. The pesticides, especially organophosphorus pesticides, were the main poisons threatening the health of people in Hangzhou, and the effective prevention and control measures should be taken immediately.

Variants in angiogenesis-related genes and the risk of clear cell renal cell carcinoma.

Angiogenesis is fundamentally important to the pathogenesis of clear cell renal cell carcinoma (ccRCC). We investigated the association between variations of genes related to angiogenesis and the risk of ccRCC. In a case-control study of 859 ccRCC patients and 1004 cancer-free subjects, we genotyped 24 potentially functional single nucleotide polymorphisms (SNPs) in seven angiogenesis-related genes (HIF1A, EPAS1, VEGFA, VEGFR1, VEGFR2, VEGFR3 and PDGFRB) using the TaqMan or Snapshot method. Unconditional logistic regression, adjusted for potential confounding factors, was used to assess the risk associations. The functionality of selected SNPs was assessed by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) and luciferase reporter gene assays. We found two SNPs (VEGFA rs2010963 and VEGFR3 rs448012) that were significantly associated with increased risk of ccRCC, after adjusting for multiple comparisons [rs2010963 CC/GC cf. GG: false discovery rate (FDR) = 0.048, odds ratio (OR) = 1.36, 95% confidence interval (95% CI) = 1.12-1.66; rs448012 CC/GC cf. GG: FDR = 0.048, OR = 1.38, 95% CI =1.13-1.69]. Real-time quantitative PCR revealed that the variant genotypes of rs2010963, but not rs448012, were associated with increased gene expression in normal tissues of ccRCC patients (CC/GC cf. GG: P = 0.036). The luciferase reporter assay showed that the rs2010963 C allele significantly increased luciferase activity over that of the rs2010963 G allele. Our results indicate that VEGFA rs2010963 and VEGFR3 rs448012 are associated with risk of ccRCC. Furthermore, rs2010963 is a functional SNP that may affect ccRCC susceptibility by modulating endogenous VEGFA expression.

Survivin mediates renal proximal tubule recovery from AKI.

AKI induces the renoprotective upregulation of survivin expression in kidney epithelial cells, but the underlying mechanisms have not been identified. To determine the role of survivin in renal recovery from AKI, we generated mice with renal proximal tubule-specific deletion of survivin (survivin(ptKO)). Renal survivin expression increased substantially in response to ischemia-reperfusion (I/R) injury in control littermates but remained minimal in survivin(ptKO) mice. Functional and histologic data indicated similar degrees of renal injury in survivin(ptKO) and control mice 24 hours after reperfusion, but recovery was markedly delayed in survivin(ptKO) mice. In MCT cells, a mouse renal proximal tubule cell line, ATP depletion by antimycin A treatment upregulated survivin expression through a phospho-STAT3-dependent pathway. In wild-type mice, inhibition of STAT3 kinase diminished I/R-induced upregulation of STAT3 phosphorylation and survivin expression and delayed recovery. Furthermore, I/R injury activated Notch-2 signaling, and a γ-secretase inhibitor suppressed I/R-induced Notch-2 signaling, STAT3 phosphorylation, and survivin expression and delayed recovery. In MCT cells, inhibition of γ-secretase similarly attenuated antimycin A-induced Notch-2 activation, upregulation of survivin, and phosphorylation of STAT3, but STAT3 kinase inhibition did not prevent Notch-2 activation. Therefore, these data suggest that STAT3 phosphorylation and subsequent upregulation of survivin expression mediated by Notch-2 signaling in renal proximal tubule epithelial cells aid in the functional and structural recovery of the kidney from AKI.

mVps34 deletion in podocytes causes glomerulosclerosis by disrupting intracellular vesicle trafficking.

Recent studies have suggested that autophagy is a key mechanism in maintaining the integrity of podocytes. The mammalian homologue of yeast vacuolar protein sorting defective 34 (mVps34) has been implicated in the regulation of autophagy, but its role in podocytes is unknown. We generated a line of podocyte-specific mVps34-knockout (mVps34(pdKO)) mice, which were born at Mendelian ratios. These mice appeared grossly normal at 2 weeks of age but exhibited growth retardation and were significantly smaller than control mice by 6 weeks of age, with no difference in ratios of kidney to body weight. mVps34(pdKO) mice developed significant proteinuria by 3 weeks of age, developed severe kidney lesions by 5-6 weeks of age, and died before 9 weeks of age. There was striking podocyte vacuolization and proteinaceous casts, with marked glomerulosclerosis and interstitial fibrosis by 6 weeks of age. Electron microscopy revealed numerous enlarged vacuoles and increased autophagosomes in the podocytes, with complete foot process effacement and irregular and thickened glomerular basement membranes. Immunoblotting of isolated glomerular lysates revealed markedly elevated markers specific for lysosomes (LAMP1 and LAMP2) and autophagosomes (LC3-II/I). Immunofluorescence staining confirmed that the enlarged vacuoles originated from lysosomes. In conclusion, these results demonstrate an indispensable role for mVps34 in the trafficking of intracellular vesicles to protect the normal cellular metabolism, structure, and function of podocytes.

Synchronization and array-enhanced resonances in delayed coupled neuronal network with channel noise.

This paper studies the combined effect of transmission delay and channel fluctuations on population behaviors of an excitatory Erdös-Rényi neuronal network. First, it is found that the network reaches a perfect spatial temporal coherence at a suitable membrane size. Such a coherence resonance is stimulus-free and is array-enhanced. Second, the presence of transmission delay can induce intermittent changes of the population dynamics. Besides, two resonant peaks of the population firing rate are observed as delay changes: one is at τd≈7ms for all membrane areas, which reflects the resonance between the delayed interaction and the intrinsic period of channel kinetics; the other occurs when the transmission delay equals to the mean inter-spike intervals of the population firings in the absence of delay, which reflects the resonance between the delayed interaction and the firing period of the non-delayed system. Third, concerning the impact of network topology and population size, it is found that decreasing the connection probability does not change the range of transmission delay but broadens the range of synaptic coupling that supports population neurons to generate action potentials synchronously and temporally coherently. Furthermore, there exists a critical connection probability that distinguishes the population dynamics into an asynchronous and synchronous state. All the results we obtained are based on networks of size N = 500, which are shown to be robust to further increasing the population size.

A LC-MS/MS method for the simultaneous quantitative determination of aldosterone, its precursor 18-hydroxycorticosterone and its metabolite tetrahydroaldosterone in human urine.

Aldosterone (ALD), its precursor 18-hydroxycorticosterone (18-OHB) and its metabolite tetrahydroaldosterone (TH-ALD) are important biomarkers for the diagnosis of primary aldosteronism (PA). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is increasingly utilized in the detection of small molecules of hormones because it has advantages in terms of specificity and sensitivity. The objective of this study is to develop a new LC-MS/MS method for the simultaneous quantification of ALD (free), 18-OHB, and TH-ALD in human urine and attempt to diagnose primary aldosteronism using different indicators. The urine samples were treated with a solid-phase extraction pretreatment technique and the three analytes were separated on a reversed-phase column and detected on a triple quadrupole mass spectrometer. The established method was validated according to CLSI C62-A standard guidelines. The calibration ranges from 25 pg/mL to 5000 pg/mL for aldosterone (free), 18-hydroxycorticosterone and tetrahydroaldosterone, and the lower limit of quantification for these three analytes was 25 pg/mL. The matrix effects and recoveries of these three analytes ranged from 85.1 % to 115 % and from 86.3 % to 114 %, respectively. The intra-day and inter-day precision ranged from 1.29 % to 6.78 % and from 1.77 % to 8.64 %, respectively. The performance of the method met the requirements of the guidelines. 40 clinical urine samples including 22 PA patients and 18 non-PA patients were detected, and the ROC curves of three diagnostic indicators were established. The area under the curve (AUC) of ALD (free) is the biggest, so ALD (free) was the best compound to be used as a diagnostic indicator in this study. When the cut-off point was taken as 141 ng/24-h, the sensitivity was 72.7 % and the specificity was 88.9 %. We developed and validated an LC-MS/MS method for the simultaneous quantification of ALD (free), 18-OHB and TH-ALD in human urine. Our study provides a reference for the use of new biomarkers for the diagnosis of primary aldosteronism.