Independent insulin signaling modulators govern hot avoidance under different feeding states.

Thermosensation is critical for the survival of animals. However, mechanisms through which nutritional status modulates thermosensation remain unclear. Herein, we showed that hungry Drosophila exhibit a strong hot avoidance behavior (HAB) compared to food-sated flies. We identified that hot stimulus increases the activity of α'ß' mushroom body neurons (MBns), with weak activity in the sated state and strong activity in the hungry state. Furthermore, we showed that α'ß' MBn receives the same level of hot input from the mALT projection neurons via cholinergic transmission in sated and hungry states. Differences in α'ß' MBn activity between food-sated and hungry flies following heat stimuli are regulated by distinct Drosophila insulin-like peptides (Dilps). Dilp2 is secreted by insulin-producing cells (IPCs) and regulates HAB during satiety, whereas Dilp6 is secreted by the fat body and regulates HAB during the hungry state. We observed that Dilp2 induces PI3K/AKT signaling, whereas Dilp6 induces Ras/ERK signaling in α'ß' MBn to regulate HAB in different feeding conditions. Finally, we showed that the 2 α'ß'-related MB output neurons (MBONs), MBON-α'3 and MBON-ß'1, are necessary for the output of integrated hot avoidance information from α'ß' MBn. Our results demonstrate the presence of dual insulin modulation pathways in α'ß' MBn, which are important for suitable behavioral responses in Drosophila during thermoregulation under different feeding states.

Mushroom body subsets encode CREB2-dependent water-reward long-term memory in Drosophila.

Long-term memory (LTM) formation depends on the conversed cAMP response element-binding protein (CREB)-dependent gene transcription followed by de novo protein synthesis. Thirsty fruit flies can be trained to associate an odor with water reward to form water-reward LTM (wLTM), which can last for over 24 hours without a significant decline. The role of de novo protein synthesis and CREB-regulated gene expression changes in neural circuits that contribute to wLTM remains unclear. Here, we show that acute inhibition of protein synthesis in the mushroom body (MB) αß or γ neurons during memory formation using a cold-sensitive ribosome-inactivating toxin disrupts wLTM. Furthermore, adult stage-specific expression of dCREB2b in αß or γ neurons also disrupts wLTM. The MB αß and γ neurons can be further classified into five different neuronal subsets including αß core, αß surface, αß posterior, γ main, and γ dorsal. We observed that the neurotransmission from αß surface and γ dorsal neuron subsets is required for wLTM retrieval, whereas the αß core, αß posterior, and γ main are dispensable. Adult stage-specific expression of dCREB2b in αß surface and γ dorsal neurons inhibits wLTM formation. In vivo calcium imaging revealed that αß surface and γ dorsal neurons form wLTM traces with different dynamic properties, and these memory traces are abolished by dCREB2b expression. Our results suggest that a small population of neurons within the MB circuits support long-term storage of water-reward memory in Drosophila.

Analysis of antiviral efficacy after switching from brand to generic entecavir in patients with treatment-naïve chronic hepatitis B.

BACKGROUND/AIMS: Entecavir (ETV) can suppress chronic hepatitis B (CHB) virus replication as a standard of treatment drugs. For the treatment of CHB, affordable generic drugs may be more widely used in developing and undeveloped countries. However, there is little real-world data regarding the clinical efficacy of switching from entecavir-brand-name drugs (ETV-Brand) to entecavir generic drugs (ETV-Generic) with 0.5 mg once daily. The aim of the study was to evaluate the antiviral activity and safety of ETV-Generic in comparison to ETV-Brand in CHB-patients. METHODS: In this single-center, retrospective, 175 treatment-naïve-CHB-patients were assigned to receive 0.5 mg of ETV-Brand per day for a least 2 years and then switched to ETV-Generic for 6 months for analysis. The primary efficacy endpoint was a sustained virological response in comparison of the rate of undetectable serum Hepatitis B deoxyribonucleic acid (HBV DNA) as the sustained virologic response at baseline and 6 months after switching. Secondary efficacy endpoints were the comparison of the alanine aminotransferase (ALT) levels between before and after switching and ALT normalization. Renal safety consideration was reported on changing the estimated glomerular filtration rate. RESULTS: From baseline to 6 months, the rate of undetectable HBV DNA and ALT levels remained stable as compared ETV-Brand period with ETV-Generic for 6 months. The rate of undetectable HBV DNA were 81.1%in ETV-Brand versus 88.0%in ETV-Generic (p = 0.05 CI 0.1-13.5%). ALT levels were 27.2 IU/L (CI 24.8-29.6 IU/L) in ETV-Brand versus 26.2 IU/L (CI 24.0-28.4 IU/L) in ETV-Generic (p = 0.55). Both endpoints were not significantly different between ETV-Brand and ETV-Generic treatments. Kidney function did not significantly differ from ETV-Brand (80.8, interquartile range [IQR]: 66.6-95.3 mL/min/1.73 m2) to ETV-Generic treatment period (80.3, IQR: 65.6-93.5 mL/min/1.73 m2). CONCLUSION: In treatment-naïve CHB-patients, the efficacy and safety profiles of switching from ETV-Brand to ETV-Generic showed no difference. Concluding the ETV-Generic comes to exciting virologic responses and rare adverse events.

Electrical synapses between mushroom body neurons are critical for consolidated memory retrieval in Drosophila.

Electrical synapses between neurons, also known as gap junctions, are direct cell membrane channels between adjacent neurons. Gap junctions play a role in the synchronization of neuronal network activity; however, their involvement in cognition has not been well characterized. Three-hour olfactory associative memory in Drosophila has two components: consolidated anesthesia-resistant memory (ARM) and labile anesthesia-sensitive memory (ASM). Here, we show that knockdown of the gap junction gene innexin5 (inx5) in mushroom body (MB) neurons disrupted ARM, while leaving ASM intact. Whole-mount brain immunohistochemistry indicated that INX5 protein was preferentially expressed in the somas, calyxes, and lobes regions of the MB neurons. Adult-stage-specific knockdown of inx5 in αß neurons disrupted ARM, suggesting a specific requirement of INX5 in αß neurons for ARM formation. Hyperpolarization of αß neurons during memory retrieval by expressing an engineered halorhodopsin (eNpHR) also disrupted ARM. Administration of the gap junction blocker carbenoxolone (CBX) reduced the proportion of odor responsive αß neurons to the training odor 3 hours after training. Finally, the α-branch-specific 3-hour ARM-specific memory trace was also diminished with CBX treatment and in inx5 knockdown flies. Altogether, our results suggest INX5 gap junction channels in αß neurons for ARM retrieval and also provide a more detailed neuronal mechanism for consolidated memory in Drosophila.

Cyclosporin A Inhibits the Activation of Membrane-Bound Guanylate Cyclase GC-A of Atrial Natriuretic Factor via NAD(P)H Oxidase.

Cyclosporin A (CsA) is a common immunosuppressant wildly used in patients with organ transplant and autoimmune diseases; however, it can cause several adverse effects, such as nephrotoxicity and hypertension. The detailed mechanisms have not been completely understood. Atrial natriuretic factor (ANF) and its receptor (mGC-A) have been shown to play a crucial role in the regulation of blood pressure. Here, we investigated the effects of CsA on the activation of mGC-A in ANF-treated LLC-PK1 cells. In our study, ANF-induced mGC-A activities and superoxide generation in LLC-PK1 cells were measured by guanosine 3',5'-cyclic monophosphate (cGMP) radioimmunoassay and lucigenin-dependent chemiluminescence, respectively. We found that CsA can reduce about 60% of mGC-A activities in ANF-treated LLC-PK1 cells. CsA is known to induce superoxide. Addition of superoxide generators menadione and diamide mimicked the effects of CsA, whereas DPI (a reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase inhibitor) and Tiron (a superoxide quencher) blocked the suppressive effects of CsA on ANF-induced mGC-A activities. We previously showed that the catalytic domain of GC-A (GC-c) expresses guanylate cyclase activities. Addition of menadione, diamide, or peroxynitrite or transfection of Nox-4 NAD(P)H oxidase abolished GC-c activities. In conclusion, CsA inhibits ANF-stimulated mGC-A activities through superoxide and/or peroxynitrite generated by an NAD(P)H oxidase by interacting with the catalytic domain of mGC-A.

Renal Tubular Epithelial TRPA1 Acts as An Oxidative Stress Sensor to Mediate Ischemia-Reperfusion-Induced Kidney Injury through MAPKs/NF-κB Signaling.

Oxidative stress and inflammation play important roles in the pathophysiology of acute kidney injury (AKI). Transient receptor potential ankyrin 1 (TRPA1) is a Ca2+-permeable ion channel that is sensitive to reactive oxygen species (ROS). The role of TRPA1 in AKI remains unclear. In this study, we used human and animal studies to assess the role of renal TRPA1 in AKI and to explore the regulatory mechanism of renal TRPA1 in inflammation via in vitro experiments. TRPA1 expression increased in the renal tubular epithelia of patients with AKI. The severity of tubular injury correlated well with tubular TRPA1 or 8-hydroxy-2'-deoxyguanosine expression. In an animal model, renal ischemia-reperfusion injury (IR) increased tubular TRPA1 expression in wild-type (WT) mice. Trpa1-/- mice displayed less IR-induced tubular injury, oxidative stress, inflammation, and dysfunction in kidneys compared with WT mice. In the in vitro model, TRPA1 expression increased in renal tubular cells under hypoxia-reoxygenation injury (H/R) conditions. We demonstrated that H/R evoked a ROS-dependent TRPA1 activation, which elevated intracellular Ca2+ level, increased NADPH oxidase activity, activated MAPK/NF-κB signaling, and increased IL-8. Renal tubular TRPA1 may serve as an oxidative stress sensor and a crucial regulator in the activation of signaling pathways and promote the subsequent transcriptional regulation of IL-8. These actions might be evident in mice with IR or patients with AKI.

Tubular transcriptional co-activator with PDZ-binding motif protects against ischemic acute kidney injury.

Transcriptional co-activator with PDZ-binding motif (TAZ) is a key downstream effector of the Hippo tumor-suppressor pathway. The functions of TAZ in the kidney, especially in tubular epithelial cells, are not well-known. To elucidate the adaptive expression, protective effects on kidney injury, and signaling pathways of TAZ in response to acute kidney injury (AKI), we used in vitro (hypoxia-treated human renal proximal tubular epithelial cells [RPTECs]) and in vivo (mouse ischemia-reperfusion injury [IRI]) models of ischemic AKI. After ischemic AKI, TAZ was up-regulated in RPTECs and the renal cortex or tubules. Up-regulation of TAZ in RPTECs subjected to hypoxia was controlled by IκB kinase (IKK)/nuclear factor κ-light-chain-enhancer of activated B cell (NF-κB) signaling. TAZ overexpression attenuated hypoxic and oxidative injury, inhibited apoptosis and activation of p38 and c-Jun N-terminal kinase (JNK) proteins, and promoted wound healing in an RPTEC monolayer. However, TAZ knockdown aggravated hypoxic injury, apoptosis, and activation of p38 and JNK signaling, delayed wound closure of an RPTEC monolayer, and promoted G0/G1 phase cell-cycle arrest. Chloroquine and verteporfin treatment produced similar results to TAZ overexpression and knockdown in RPTECs, respectively. Compared with vehicle-treated mice, chloroquine treatment increased TAZ in the renal cortex and tubules, improved renal function, and attenuated tubular injury and tubular apoptosis after renal IRI, whereas TAZ siRNA and verteporfin decreased TAZ in the renal cortex and tubules, deteriorated renal failure and tubular injury, and aggravated tubular apoptosis. Our findings indicate the renoprotective role of tubular TAZ in ischemic AKI. Drugs augmenting (e.g., chloroquine) or suppressing (e.g., verteporfin) TAZ in the kidney might be beneficial or deleterious to patients with AKI.

Differential protective effects of connective tissue growth factor against Aß neurotoxicity on neurons and glia.

Impaired clearance of amyloid-ß peptide (Aß) leads to abnormal extracellular accumulation of this neurotoxic protein that drives neurodegeneration in sporadic Alzheimer's disease (AD). Connective tissue growth factor (CTGF/CCN2) expression is elevated in plaque-surrounding astrocytes in AD patients. However, the role of CTGF in AD pathogenesis remains unclear. Here we characterized the neuroprotective activity of CTGF. We found that CTGF facilitated Aß uptake and subsequent degradation within primary glia and neuroblastoma cells. CTGF enhanced extracellular Aß degradation via membrane-bound matrix metalloproteinase-14 (MMP14) in glia and extracellular MMP13 in neurons. In the brain of a Drosophila AD model, glial-expression of CTGF reduced Aß deposits, improved locomotor function, and rescued memory deficits. Neuroprotective potential of CTGF against Aß42-induced photoreceptor degeneration was disrupted through silencing MMPs. Therefore, CTGF may represent a node for potential AD therapeutics as it intervenes in glia-neuron communication via specific MMPs to alleviate Aß neurotoxicity in the central nervous system.

Dysfunction of different cellular degradation pathways contributes to specific ß-amyloid42-induced pathologies.

The endosomal-lysosomal system (ELS), autophagy, and ubiquitin-proteasome system (UPS) are cellular degradation pathways that each play a critical role in the removal of misfolded proteins and the prevention of the accumulation of abnormal proteins. Recent studies on Alzheimer's disease (AD) pathogenesis have suggested that accumulation of aggregated ß-amyloid (Aß) peptides in the AD brain results from a dysfunction in these cellular clearance systems. However, the specific roles of these pathways in the removal of Aß peptides and the pathogenesis underlying AD are unclear. Our in vitro and in vivo genetic approaches revealed that ELS mainly removed monomeric ß-amyloid42 (Aß42), while autophagy and UPS clear oligomeric Aß42. Although overproduction of phosphatidylinositol 4-phosphate-5 increased Aß42 clearance, it reduced the life span of Aß42 transgenic flies. Our behavioral studies further demonstrated impaired autophagy and UPS-enhanced Aß42-induced learning and memory deficits, but there was no effect on Aß42-induced reduction in life span. Results from genetic fluorescence imaging showed that these pathways were damaged in the following order: UPS, autophagy, and finally ELS. The results of our study demonstrate that different degradation pathways play distinct roles in the removal of Aß42 aggregates and in disease progression. These findings also suggest that pharmacologic treatments that are designed to stimulate cellular degradation pathways in patients with AD should be used with caution.-Ji, X.-R., Cheng, K.-C., Chen, Y.-R., Lin, T.-Y., Cheung, C. H. A., Wu, C.-L., Chiang, H.-C. Dysfunction of different cellular degradation pathways contributes to specific ß-amyloid42-induced pathologies.

High particulate matter 2.5 levels and ambient temperature are associated with acute lung edema in patients with nondialysis Stage 5 chronic kidney disease.

BACKGROUND: Numerous studies have shown that exposure to air pollution, especially particulate matter (PM) with a diameter <2.5 µm (PM2.5), was associated with various diseases. We tried to determine the impact of PM2.5 and other weather factors on acute lung edema in patients with Stage 5 nondialysis chronic kidney disease (CKD Stage 5-ND). METHODS: In total, 317 CKD Stage 5-ND (estimated glomerular filtration rate 6.79 ± 4.56 mL/min) patients residing in central Taiwan who developed acute lung edema and initiated long-term dialysis were included in this case-crossover study. Pearson's correlation test was used to examine the relationship of acute lung edema cases with PM2.5 levels and ambient temperature separately. RESULTS: The average PM2.5 level within the 7-day period correlated with acute lung edema incidence in the fall [adjusted odds ratio (OR) 3.23, P = 0.047] and winter (adjusted OR 1.99, P < 0.001). In winter, even a 3-day exposure to PM2.5 was associated with increased risk (adjusted OR 1.55, P < 0.001). The average temperatures within 3 days in spring and summer were correlated positively with the risk (adjusted OR 2.77 P < 0.001 and adjusted OR 2.72, P < 0.001, respectively). In the fall and winter, temperatures were correlated negatively with the risk (adjusted OR 0.36, P < 0.001 and adjusted OR 0.54, P < 0.001, respectively). CONCLUSIONS: A high PM2.5 level was associated with an increased risk of acute lung edema. High ambient temperature in hot seasons and low ambient temperature in cold seasons were also associated with increased risk. It is essential to educate these patients to avoid areas with severe air pollution and extreme ambient temperature.

Favourable renal outcomes after intravenous thrombolytic therapy for acute ischemic stroke: Clinical implication of kidney-brain axis.

AIM: Recombinant tissue plasminogen activator (rt-PA) administration is the most prevalent treatment for acute ischemic within golden time. However, the effects of rt-PA on the kidney function in such patients remain unknown. This study determined long-term renal outcomes in patients with acute ischemic stroke receiving systemic rt-PA. METHODS: We enroled patients who were hospitalized for acute ischemic stroke from January 2001 to January 2017. We applied 1:2 propensity score matching to eliminate various confounding variables. We defined surrogate renal outcomes as declining of estimated glomerular filtration rate (eGFR) greater than 30% and 50%, and chronic kidney disease (CKD) with eGFR less than 60 mL/min. We then compared the 1-year eGFR with paired t-test in patients treated with or without rt-PA. RESULTS: Overall, 343 of 1739 patients received rt-PA within golden time. After 1:2 propensity score matching, their baseline characteristics were grouped as treated with rt-PA (n = 235) or not (n = 394). rt-PA-treated patients exhibited slower renal progression, including the risk of eGFR declining greater than 30% (hazard ratio (HR), 0.72; P = 0.03), risk of declining eGFR greater than 50% (HR, 0.63; P = 0.046) and risk of CKD (HR, 0.61; P = 0.005). After 1-year cohort, the rt-PA group exhibited an improved renal outcome by the paired t-test (propensity match: ΔGFR = 9.1 (95% confidence interval: 6.3, 11.8), P < 0.001 in rt-PA group; ΔGFR = -1.1 (95% confidence interval: -2.9, 0.7), P = 0.23 in non-rt-PA group). In patients with eGFR less than 45 mL/min (n = 34), intracerebral haemorrhage was not reported. CONCLUSION: Patients receiving rt-PA for acute ischemic stroke exhibit favourable renal outcomes, and no increased incidence of intracerebral haemorrhage occurs in rt-PA patients with advanced CKD.

Urinary cell-free mitochondrial and nuclear deoxyribonucleic acid correlates with the prognosis of chronic kidney diseases.

INTRODUCTION: Cell-free deoxyribonucleic acid DNA (cf-DNA) in urine is promising due to the advantage of urine as an easily obtained and non-invasive sample source over tissue and blood. In clinical practice, it is important to identify non-invasive biomarkers of chronic kidney disease (CKD) in monitoring and surveillance of disease progression. Information is limited, however, regarding the relationship between urine and plasma cf-DNA and the renal outcome in CKD patients. METHODS: One hundred and thirty-one CKD patients were enrolled between January 2016 and September 2018. Baseline urine and plasma cell-free mitochondrial DNA (cf-mtDNA) and cell-free nuclear DNA (cf-nDNA) were isolated using quantitative real-time PCR. Estimated glomerular filtration rate (eGFR) measurement was performed at baseline and 6-month follow-up. Favorable renal outcome was defined as eGFR at 6 months minus baseline eGFR> = 0. Receiver operator characteristics (ROC) curve analysis was performed to assess different samples of cf-DNA to predict favorable renal outcomes at 6 months. A multivariate linear regression model was used to evaluate independent associations between possible predictors and different samples of cf-DNA. RESULTS: Patients with an advanced stage of CKD has significantly low plasma cf-nDNA and high plasma neutrophil gelatinase-associated lipocalin (NGAL) levels. Low urine cf-mtDNA, cf-nDNA levels and low plasma NGAL were significantly correlated with favorable renal outcomes at 6 months. The urine albumin-creatinine ratio (ACR) or urine protein-creatinine ratio (PCR) level is a robust predictor of cf-mtDNA and cf-nDNA in CKD patients. Baseline urine levels of cf-mtDNA and cf-nDNA could predict renal outcomes at 6 months. CONCLUSIONS: Urinary cf-mtDNA and cf-nDNA may provide novel prognostic biomarkers for renal outcome in CKD patients. The levels of plasma cf-nDNA and plasma NGAL are significantly correlated with the severity of CKD.

Additive Expression of Consolidated Memory through Drosophila Mushroom Body Subsets.

Associative olfactory memory in Drosophila has two components called labile anesthesia-sensitive memory and consolidated anesthesia-resistant memory (ARM). Mushroom body (MB) is a brain region critical for the olfactory memory and comprised of 2000 neurons that can be classified into αß, α'ß', and γ neurons. Previously we demonstrated that two parallel pathways mediated ARM consolidation: the serotonergic dorsal paired medial (DPM)-αß neurons and the octopaminergic anterior paired lateral (APL)-α'ß' neurons. This finding prompted us to ask how this composite ARM is retrieved. Here, we showed that blocking the output of αß neurons and that of α'ß' neurons each impaired ARM retrieval, and blocking both simultaneously had an additive effect. Knockdown of radish and octß2R in αß and α'ß' neurons, respectively, impaired ARM. A combinatorial assay of radish mutant background rsh1 and neurotransmission blockade confirmed that ARM retrieved from α'ß' neuron output is independent of radish. We identified MBON-ß2ß'2a and MBON-ß'2mp as the MB output neurons downstream of αß and α'ß' neurons, respectively, whose glutamatergic transmissions also additively contribute to ARM retrieval. Finally, we showed that α'ß' neurons could be functionally subdivided into α'ß'm neurons required for ARM retrieval, and α'ß'ap neurons required for ARM consolidation. Our work demonstrated that two parallel neural pathways mediating ARM consolidation in Drosophila MB additively contribute to ARM expression during retrieval.

Mushroom body glycolysis is required for olfactory memory in Drosophila.

Glucose catabolism, also known as glycolysis, is important for energy generation and involves a sequence of enzymatic reactions that convert a glucose molecule into two pyruvate molecules. The glycolysis process generates adenosine triphosphate as a byproduct. In this study, we investigated whether glycolysis plays a role in maintaining neuronal functions in the Drosophila mushroom bodies (MBs), which are generally accepted to be an olfactory learning and memory center. Our data showed that individual knockdown of glycolytic enzymes in the MBs, including hexokinase (HexA), phosphofructokinase (Pfk), or pyruvate kinase (PyK), disrupts olfactory memory. Whole-mount brain immunostaining indicated that pyruvate kinase is strongly expressed in the MB αß, α'ß', and γ neuron subsets. We conclude that HexA, Pfk, and PyK are required in each MB neuron subset for olfactory memory formation. Our data therefore indicates that glucose catabolism in the MBs is important for olfactory memory formation in Drosophila.

Prospective associations between environmental heavy metal exposure and renal outcomes in adults with chronic kidney disease.

AIM: In Taiwan, Changhua County residents were exposed to high heavy metal pollution and exhibited high heavy metal levels in blood and urine. We examined associations between heavy metals in residential soil and renal outcomes of residents with chronic kidney disease (CKD). METHOD: From 1 January 2003 to 30 June 2015, we retrospectively identified CKD patients with an estimated glomerular filtration rate of <60 mL/min per 1.73 m2 at one tertiary care centre. We linked data displaying heavy metal concentrations from farm soil adjacent to the patients' residences to clinical outcomes. We included 2343 CKD patients (533 with progression to end-stage renal disease [ESRD] and 1810 without]. We followed these patients for 3.49 ± 2.27 years, until death or initiation of maintenance dialysis. RESULTS: There were high correlations among the concentrations of the eight metals: arsenic, cadmium, chromium, mercury, copper, lead, nickel, and zinc. After factor analysis, chromium, copper, nickel, and zinc were grouped and labelled Factor 1. High Factor 1 concentration near the patients' residences was associated with diagnoses of hypertension, diabetes mellitus, and cerebral vascular accident. Patients living in areas with high Factor 1 concentrations were at higher risk of ESRD. After multivariate adjustment [adjusted hazard ratio: 1.08, 95% Confidence interval: 1.01-1.14, P = 0.02], only zinc and nickel were risk factors for progression to ESRD. CONCLUSION: Patients with CKD, with long-term exposure to soil-based heavy metals, had rapid progression to ESRD. Groups of minerals from the same source of contamination may accumulate and lead to additional harm.

Roles of p62 in BDNF-dependent autophagy suppression and neuroprotection against mitochondrial dysfunction in rat cortical neurons.

Previously, we have reported that pre-conditioning of primary rat cortical neurons with brain-derived neurotrophic factor (BDNF) may exert neuroprotective effects against 3-nitropropionic acid (3-NP), a mitochondrial complex II inhibitor. However, the underlying mechanisms, especially potential involvements of autophagy, remain elusive. In this work, we tested the hypothesis that BDNF may suppress 3-NP-induced autophagy to exert its neuroprotective effects by inducing the expression of p62/sequestosome-1 in primary cortical neurons. We found that 3-NP increased total level of microtubule-associated protein 1A/1B-light chain (LC)-3 as well as the LC3-II/LC3-I ratio, an index of autophagy, in primary cortical neurons. BDNF decreased LC3-II/LC3-I ratio and time-dependently induced expression of p62. Knockdown of p62 by siRNA restored LC3-II/LC3-I ratio and increased total LC3 levels associated with BDNF exposure; p62 knockdown also abolished BDNF-dependent neuroprotection against 3-NP. Upstream of p62, we found that BDNF triggered phosphorylation of mammalian target of rapamycin (mTOR) and its downstream mediator p70S6K; importantly, the mTOR inhibitor rapamycin reduced both BDNF-dependent p62 induction as well as 3-NP resistance. BDNF is known to induce c-Jun in cortical neurons. We found that c-Jun knockdown in part attenuated BDNF-mediated p62 induction, whereas p62 knockdown had no significant effects on c-Jun expression. In addition to suppressing p62 induction, rapamycin also partially suppressed BDNF-induced c-Jun expression, but c-Jun knockdown failed to affect mTOR activation. Together, our results suggested that BDNF inhibits 3-NP-induced autophagy via, at least in part, mTOR/c-Jun-dependent induction of p62 expression, together contributing to neuroprotection against mitochondrial inhibition.

Urinary glycated uromodulin in diabetic kidney disease.

Advanced glycation end-products (AGEs) form during oxidative stress, which is increased in diabetes mellitus (DM). Uromodulin is a protein with a renal protective effect, and may be subject to glycation. The implications of uromodulin glycation and AGEs in the urine are not understood. Here, immunoprecipitation and liquid chromatography-mass spectrometry identified glycated uromodulin (glcUMOD) in the urine of 62.5% of patients with diabetic kidney disease (DKD), 20.0% of patients with non-diabetic chronic kidney disease (CKD), and no DM patients with normal renal function or healthy control participants; a finding replicated in a larger cohort of 84 patients with CKD in a case-control study (35 with DM, 49 without). Uromodulin forms high molecular weight polymers that associate with microvesicles and exosomes. Differential centrifugation identified uromodulin in the supernatant, microvesicles, and exosomes of the urine of healthy participants, but only in the supernatant of samples from patients with DKD, suggesting that glycation influences uromodulin function. Finally, the diagnostic and prognostic utility of measuring urinary glcUMOD concentration was examined. Urinary glcUMOD concentration was substantially higher in DKD patients than non-diabetic CKD patients. Urinary glcUMOD concentration predicted DKD status, particularly in patients with CKD stages 1-3a aged <65 years and with urine glcUMOD concentration ≥9,000 arbitrary units (AU). Urinary uromodulin is apparently glycated in DKD and forms AGEs, and glcUMOD may serve as a biomarker for DKD.

More Insight into BDNF against Neurodegeneration: Anti-Apoptosis, Anti-Oxidation, and Suppression of Autophagy.

In addition to its well-established neurotrophic action, brain-derived neurotrophic factor (BDNF) also possesses other neuroprotective effects including anti-apoptosis, anti-oxidation, and suppression of autophagy. We have shown before that BDNF triggers multiple mechanisms to confer neuronal resistance against 3-nitropropionic acid (3-NP)-induced mitochondrial dysfunction in primary rat cortical cultures. The beneficial effects of BDNF involve the induction of anti-oxidative thioredoxin with the resultant expression of anti-apoptotic B-cell lymphoma 2 (Bcl-2) as well as erythropoietin (EPO)-dependent stimulation of sonic hedgehog (SHH). We further revealed that BDNF may bring the expression of sulfiredoxin, an ATP-dependent antioxidant enzyme, to offset mitochondrial inhibition in cortical neurons. Recently, we provided insights into another novel anti-oxidative mechanism of BDNF, which involves the augmentation of sestrin2 expression to endow neuronal resistance against oxidative stress induced by 3-NP; BDNF induction of sestrin2 entails the activation of a pathway involving nitric oxide (NO), cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG), and nuclear factor-κB (NF-κB). Apart from anti-apoptosis and anti-oxidation, we demonstrated in our most recent study that BDNF may activate the mammalian target of rapamycin (mTOR) with resultant activation of transcription factor c-Jun, thereby stimulating the expression of p62/sequestosome-1 to suppress heightened autophagy as a result of 3-NP exposure. Together, our results provide in-depth insight into multi-faceted protective mechanisms of BDNF against mitochondrial dysfunction commonly associated with the pathogenesis of many chronic neurodegenerative disorders. Delineation of the protective signaling pathways elicited by BDNF would endow a rationale to develop novel therapeutic regimens to halt or prevent the progression of neurodegeneration.

Lower-dose warfarin delays renal progression and prolongs patient survival in patients with stage 3 - 5 chronic kidney disease and nonvalvular atrial fibrillation: a 12-year follow-up study.

BACKGROUND: Anticoagulants are used to reduce the risk of stroke in patients with atrial fibrillation (Af) and chronic kidney disease (CKD). Warfarin is one of the commonly used anticoagulants; however, its effect on renal function remains unclear. METHODS: In a retrospective cohort study (January 2001 - July 2013), we surveyed data charts from 2,450 patients with stage 3 - 5 CKD, and enrolled 159 patients with Af. In total, 104 patients had a CHADS2 score of >= 2 (congestive heart failure, hypertension, >= 75 years old, diabetes, 1 point; prior stroke or transient ischemic attack or thromboembolism, 2 points). These patients were categorized into groups A and B based on warfarin treatment. Group A included 73 patients and was not undergoing warfarin treatment and group B included 31 patients undergoing warfarin treatment. The baseline demographic and biochemical data as well as changes in estimated glomerular filtration rate (eGFR) after 6, 12, and 18 months of warfarin treatment were analyzed. We also studied censored patient survival over 12 years using Kaplan-Meier model. RESULTS: The mean international normalization ratio (INR) of warfarin treatment in group B was 1.92 ± 1.04. Moreover, group B showed a significant increase in eGFR. The maximum improvement was at 6 months (mean eGFR increased from 25.97 to 31.12 mL/min; p = 0.01) and lasted for up to 18 months (eGFR 28.65 mL/min). Despite higher initial CHADS2 scores, group B showed a superior survival rate compared with group A (p = 0.02). CONCLUSION: Lower doses of warfarin may protect against renal dysfunction and could be beneficial for treatment of stage 3 - 5 CKD with Af.