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Recent case reports suggest that coronavirus disease 2019 (COVID-19) is associated with collapsing glomerulopathy in African Americans with apolipoprotein L1 gene (APOL1) risk alleles; however, it is unclear whether disease pathogenesis is similar to HIV-associated nephropathy. RNA sequencing analysis of a kidney biopsy specimen from a patient with COVID-19–associated collapsing glomerulopathy and APOL1 risk alleles (G1/G1) revealed similar levels of APOL1 and angiotensin-converting enzyme 2 (ACE2) messenger RNA transcripts as compared with 12 control kidney samples downloaded from the GTEx (Genotype-Tissue Expression) Portal. Whole-genome sequencing of the COVID-19–associated collapsing glomerulopathy kidney sample identified 4 indel gene variants, 3 of which are of unknown significance with respect to chronic kidney disease and/or focal segmental glomerulosclerosis. Molecular profiling of the kidney demonstrated activation of COVID-19–associated cell injury pathways such as inflammation and coagulation. Evidence for direct severe acute respiratory syndrome coronavirus 2 infection of kidney cells was lacking, which is consistent with the findings of several recent studies. Interestingly, immunostaining of kidney biopsy sections revealed increased expression of phospho-STAT3 (signal transducer and activator of transcription 3) in both COVID-19–associated collapsing glomerulopathy and HIV-associated nephropathy as compared with control kidney tissue. Importantly, interleukin 6–induced activation of STAT3 may be a targetable mechanism driving COVID-19–associated acute kidney injury.

Background: Podocyte foot process effacement is a key histologic finding in proteinuric kidney disease. We previously showed that 3-week old CD2AP-deficient mice have significant proteinuria, glomerular hypertrophy and mesangial expansion. The goal of this study is to use morphometry to establish the temporal sequence of podocyte foot process effacement, glomerular volume expansion and albuminuria in Cd2ap−/− mice by measuring these parameters at the 2-week time point.Methods: Wild-type mice age 14 ± 1 days with the Cd2ap gene (WT, N = 5) and mice deficient for Cd2ap (Cd2ap KO, N = 5) were generated. Kidneys were harvested and fixed in 2.5% glutaraldehyde and processed for examination by light and electron microscopy. An average of 415.2 (range 268–716) grid points were counted for all the glomeruli, and quantification of glomerular volume from each kidney. Urine was collected the day prior to sacrifice for urine albumin-to-creatinine ratio (ACR) measurements.Results: There was no difference in albuminuria [median (range) mg/g] between WT [212.2 (177.6–388.4) mg/g] vs. Cd2ap KO mice [203.3 (164.7–910.2) mg/g], P = 0.89; or glomerular volume 68,307[10,931] vs. 66,844[13,022] μm3, p = 0.92. The volume densities of glomerular components of the podocyte, capillary lumen and mesangium were not different for the two groups, P = 0.14, 0.14 and 0.17 respectively. However, foot process width was increased in Cd2ap KO 1128[286] vs. WT [374 ± 42] nm, P = 0.02.Conclusion: Here we show that while 2-week old WT and Cd2ap KO mice have similar levels of albuminuria, glomerular and mesangial volume, Cd2ap KO mice have more extensive podocyte foot process effacement. The data suggests that podocyte injury is the initiating event leading to mesangial expansion and albuminuria in this model.

Background and study aims Small bowel capsule endoscopy [SBCE) has an established role in investigating suspected small bowel bleeding [SSBB). Identification of a biomarker to predict pathology would maximize utility of this valuable diagnostic modality. This study aimed to investigate if fecal immunochemical test [FIT) could predict likelihood of small bowel pathology on SBCE. Patients and methods Patients referred for SBCE to investigate anaemia or suspected small bowel bleeding were prospectively recruited. All patients had negative upper and lower endoscopy prior to referral. A FIT ≥ 45 ug Hb/g was considered positive. SBCE was positive if a potential source of SSBB was identified. The primary endpoint was correlation between FIT and positive SBCE. Secondary endpoints were correlation between anemia and SBCE and a combination of anemia plus FIT and SBCE. Results Fifty-one patients were included in the final study cohort. 29.4 % had a positive FIT, 33.3 % were anemic, and 25.5 % patients had significant SBCE findings. There was a statistically significant association between positive FIT and pathology on SBCE (OR 12, 95 % CI [2.8 – 51.9), P = 0.001). Sensitivity and specificity of positive FIT in predicting SBCE findings were 69 % and 84 %, respectively. A normal Hb had an NPV of 83 % (OR 0.30, P = 0.09). Combining Hb and FIT was statistically significant in predicting pathology on SBCE (OR 9.14, 67 % PPV, 82 % NPV, P = 0.025). Conclusion FIT ≥ 45 ug Hb/g is a useful tool in predicting small bowel pathology on SBCE. Use of this biomarker alone, or in combination with serum haemoglobin, has value as a screening tool and may help to better triage patients referred for SBCE.

Urinary plasminogen/plasmin, or plasmin (ogen) uria, has been demonstrated in proteinuric patients and exposure of cultured podocytes to plasminogen results in injury via oxidative stress pathways. A causative role for plasmin (ogen) as a "second hit" in kidney disease progression has yet to have been demonstrated in vivo. Additionally, association between plasmin (ogen) uria and kidney function in glomerular diseases remains unclear. We performed comparative studies in a puromycin aminonucleoside (PAN) nephropathy rat model treated with amiloride, an inhibitor of plasminogen activation, and measured changes in plasmin (ogen) uria. In a glomerular disease biorepository cohort (n = 128), we measured time-of-biopsy albuminuria, proteinuria, and plasmin (ogen) uria for correlations with kidney outcomes. In cultured human podocytes, plasminogen treatment was associated with decreased focal adhesion marker expression with rescue by amiloride. Increased glomerular plasmin (ogen) was found in PAN rats and focal segmental glomerulosclerosis (FSGS) patients. PAN nephropathy was associated with increases in plasmin (ogen) uria and proteinuria. Amiloride was protective against PAN-induced glomerular injury, reducing CD36 scavenger receptor expression and oxidative stress. In patients, we found associations between plasmin (ogen) uria and edema status as well as eGFR. Our study demonstrates a role for plasmin (ogen)-induced podocyte injury in the PAN nephropathy model, with amiloride having podocyte-protective properties. In one of the largest glomerular disease cohorts to study plasminogen, we validated previous findings while suggesting a potentially novel relationship between plasmin (ogen) uria and estimated glomerular filtration rate (eGFR). Together, these findings suggest a role for plasmin (ogen) in mediating glomerular injury and as a viable targetable biomarker for podocyte-sparing treatments.

Safety data for the multicomponent meningococcal group B vaccine (4CMenB) has so far been limited to experience from clinical trials and isolated local outbreaks. Since the UK is the first country to implement a nationwide routine immunisation programme with 4CMenB (at age 8 weeks, 16 weeks, and then 1 year), we aimed to assess the safety of 4CMenB in this setting.In this prospective surveillance study, we assessed suspected adverse reactions of 4CMenB in children up to age 18 months reported in the UK Yellow Card Scheme and primary care records extracted from the Clinical Practice Research Datalink (CPRD). We proactively assessed reports of fever, local reactions, Kawasaki disease, seizures, and sudden death, and compared the number of spontaneous reports with the expected number of events based on background incidence and the number of children vaccinated. We also identified any unexpected adverse reactions and estimated compliance with subsequent doses of routine vaccinations.From Sept 1, 2015, to May 31, 2017, approximately 1·29 million children aged 2-18 months received about a combined 3 million doses of 4CMenB. 902 reports of suspected adverse reactions were received through the UK Yellow Card Scheme, of which 366 (41%) were related to local reactions and 364 (40%) related to fever. The only unexpected finding was that 160 reports of local reactions described a persistent nodule at the site of injection, usually without other local symptoms. There were 55 (6%) reports of seizures, with an age-adjusted observed-to-expected ratio of 0·13 (95% CI 0·10-0·17). Ecological analyses found similar rates of seizures within 7 days of routine immunisation in the periods before and after 4CMenB introduction, with incidence rate ratios of 1·30 (95% CI 0·56-3·00) at age 2 months, 1·53 (0·49-4·74) at age 4 months, and 1·26 (0·69-2·32) at age 12 months. Of the 902 reports, three (1%) were of Kawasaki disease (observed-to-expected ratio 1·40, 95% CI 0·29-4·08) and three (1%) of sudden infant death syndrome within 3 days of vaccination in children aged 2-4 months (0·44, 0·12-1·14). Analysis of routine immunisations recorded in CPRD found that 11 602 (95·1%) of 12 199 children had received the second dose of 4CMenB by 26 weeks of age, 1793 (84·7%) of 2117 had received the third dose by 62 weeks of age, and 4CMenB introduction had not reduced compliance with doses of other routine vaccinations.We found no significant safety concerns after widespread use of 4CMenB in UK infants, and the vaccine appears to have been well accepted by parents. However, it is important to continue monitoring the safety and long-term effect of the immunisation programme in the UK to further characterise the reported suspected adverse reactions.None.

Urinary plasminogen/plasmin, or plasmin(ogen)uria, has been demonstrated in proteinuric patients and exposure of cultured podocytes to plasminogen results in injury via oxidative stress pathways. A causative role for plasmin(ogen) as a “second hit” in kidney disease progression has yet to be demonstratedin vivo, and the association between plasmin(ogen)uria and kidney function in glomerular diseases remains unclear. We performed comparative studies in a puromycin aminonucleoside (PAN) nephropathy rat model treated with amiloride, an inhibitor of plasminogen activation, and measured changes in plasmin(ogen)uria and urinary endothelin-1 (ET1). In a glomerular disease biorepository cohort (n=128), we measured time-of-biopsy albuminuria, proteinuria, and plasmin(ogen)uria for correlations with renal outcomes. Increased glomerular plasmin(ogen) was found in PAN rats and FSGS patients. PAN nephropathy was associated with increases in plasmin(ogen)uria, proteinuria, and urinary ET1. Amiloride was protective against PAN-induced glomerular injury, reducing urinary ET1 and oxidative stress. In patients, we found associations between plasmin(ogen)uria and edema status as well as eGFR. Our study demonstrates a role for plasmin(ogen)-induced podocyte injury in the PAN nephropathy model, with amiloride having podocyte-protective properties. In one of largest glomerular disease cohorts to study plasminogen, we validated previous findings while suggesting a potentially novel relationship between plasmin(ogen)uria and eGFR. Together, these findings suggest a role for plasmin(ogen) in mediating glomerular injury and as a viable targetable biomarker for podocyte-sparing treatments.TRANSLATIONAL STATEMENTProteinuria is associated with CKD progression, and increased cardiovascular morbidity and mortality. The underlying mechanisms of podocyte injury, the hallmark of proteinuric kidney disease, are poorly understood with limited, non-specific therapeutic options. This study adds to the evidence that plasmin(ogen) in the urine of proteinuric patients is associated with podocyte injury, edema, and impaired renal function. Previously published results from us and others, taken together with our current rodent model and human data, suggest that urinary plasmin(ogen) is a potential targetable biomarker. Efforts to decrease plasmin(ogen)-mediated podocyte injury could be part of a novel therapeutic strategy for glomerular disease.

Podocytes are the key target for injury in proteinuric glomerular diseases that result in podocyte loss, progressive focal segmental glomerular sclerosis (FSGS), and renal failure. Current evidence suggests that the initiation of podocyte injury and associated proteinuria can be separated from factors that drive and maintain these pathogenic processes leading to FSGS. In nephrotic urine aberrant glomerular filtration of plasminogen (Plg) is activated to the biologically active serine protease plasmin by urokinase-type plasminogen activator (uPA). In vivo inhibition of uPA mitigates Plg activation and development of FSGS in several proteinuric models of renal disease including 5/6 nephrectomy. Here, we show that Plg is markedly increased in the urine in two murine models of proteinuric kidney disease associated with podocyte injury: Tg26 HIV-associated nephropathy and the Cd2ap−/−model of FSGS. We show that human podocytes express uPA and three Plg receptors: uPAR, tPA, and Plg-RKT. We demonstrate that Plg treatment of podocytes specifically upregulates NADPH oxidase isoforms NOX2/NOX4 and increases production of mitochondrial-dependent superoxide anion (O2−) that promotes endothelin-1 synthesis. Plg via O2−also promotes expression of the B scavenger receptor CD36 and subsequent increased intracellular cholesterol uptake resulting in podocyte apoptosis. Taken together, our findings suggest that following disruption of the glomerular filtration barrier at the onset of proteinuric disease, podocytes are exposed to Plg resulting in further injury mediated by oxidative stress. We suggest that chronic exposure to Plg could serve as a “second hit” in glomerular disease and that Plg is potentially an attractive target for therapeutic intervention.

© 2016 by the American Society of Nephrology.FSGS is the most common primary glomerular disease underlying ESRD in the United States and is increasing in incidence globally. FSGS results from podocyte injury, yet the mechanistic details of disease pathogenesis remain unclear. This has resulted in an unmet clinical need for cell-specific therapy in the treatment of FSGS and other proteinuric kidney diseases.We previously identified Yes-associated protein (YAP) as a prosurvival signaling molecule, the in vitro silencing of which increases podocyte susceptibility to apoptotic stimulus. YAP is a potent oncogene that is a prominent target for chemotherapeutic drug development. In this study, we tested the hypothesis that podocyte-specific deletion of Yap leads to proteinuric kidney disease through increased podocyte apoptosis. Yap was selectively silenced in podocytes using Cre-mediated recombination controlled by the podocin promoter. Yap silencing in podocytes resulted in podocyte apoptosis, podocyte depletion, proteinuria, and an increase in serum creatinine. Histologically, features characteristic of FSGS, including mesangial sclerosis, podocyte foot process effacement, tubular atrophy, interstitial fibrosis, and casts, were observed. In human primary FSGS, we noted reduced glomerular expression of YAP. Taken together, these results suggest a role for YAP as a physiologic antagonist of podocyte apoptosis, the signaling of which is essential for maintaining the integrity of the glomerular filtration barrier. These data suggest potential nephrotoxicity with strategies directed toward inhibition of YAP function. Further studies should evaluate the role of YAP in proteinuric glomerular disease pathogenesis and its potential utility as a therapeutic target.

Podocyte loss is central to the progression of proteinuric kidney diseases leading to end-stage kidney disease (ESKD), requiring renal replacement therapy, such as dialysis. Despite modern tools and techniques, the 5-year mortality of some patients requiring dialysis remains at about 70% to 80%. Thus, there is a great unmet need for podocyte-specific treatments aimed at preventing podocyte loss and the ensuing development of ESKD. Here, we show that ablation of the podocyte death-promoting protein dendrin delays the onset of ESKD, thereby expanding the life span of mice lacking the adapter protein CD2AP. Ablation of dendrin delays onset and severity of proteinuria and podocyte loss. In addition, dendrin ablation ameliorates mesangial volume expansion and up-regulation of mesangial fibronectin expression, which is mediated by a podocyte-secreted factor. In conclusion, onset of ESKD and death can be markedly delayed by blocking the function of dendrin.

Background: Metabotropic glutamate receptors 2/3 (mGluR2/3) and 5 (mGluR5) are novel therapeutic targets for major depression (MD), bipolar disorder (BD) and schizophrenia. We aimed to determine whether mGluR2/3 and mGluR5 binding in the anterior cingulate cortex (ACC), a brain region essential for the regulation of mood, cognition and emotion, were differentially altered in these pathologies. Methods: Using postmortem human brains derived from 2 cohorts, [ 3 H]LY341495 binding to mGluR2/3 and [ 3 H]MPEP binding to mGluR5 were measured by receptor autoradiography in the ACC. The first cohort comprised samples from individuals who had MD with psychosis (MDP), MD without psychosis (MDNP) and matched controls (n = 11–12 per group). The second cohort comprised samples from individuals who had MDNP, BD, schizophrenia and matched controls (n = 15 per group). Results: No differences in mGluR2/3 or mGluR5 binding were observed in the MDP, MDNP, BD or schizophrenia groups compared with the control group (all p > 0.05). Importantly, there were also no differences in binding densities between the psychiatric disorders (p > 0.05). We did, however, observe agerelated effects, with consistent negative associations between mGluR2/3 and age in the control group (r < –0.575, p < 0.025) and the psychotic disorder groups (MDP and schizophrenia: r = –0.765 to –0.515, p < 0.05), but not in the mood disorder groups (MDNP, BD). Limitations: Replication in larger independent cohorts and medication-naive individuals would strengthen these findings. Conclusion: Our findings suggest that mGluRs are unaltered in the ACC; however, the presence of altered receptor function cannot be discounted and requires further investigation. Taken together with previous studies, which report differential changes in mGluR2, 3 and 5 across these disorders, we suggest mGluRs may be affected in a brain region–specific manner.

NPAS3 is a developmentally important transcription factor that has been associated with psychiatric illness. Our aim is to better define the regulation of NPAS3 mRNA (messenger RNA) levels during normal human prefrontal cortical development and in schizophrenia. Utilizing postmortem tissue from 134 human brains, we assessed: 60 normal brains ranging in age from birth to adulthood, 37 chronic individuals with schizophrenia, and 37 matched controls. mRNA and microRNA (miRNA) expressions were measured by microarray and quantitative real-time PCR. Protein expression was measured by Western blotting. During human postnatal cortical development (neonate to adult), we found decreased NPAS3 mRNA yet increased NPAS3 protein expression, suggesting the involvement of posttranscriptional regulation. Through screening, we identified one NPAS-targeted miRNA (miR-17) that changed in a pattern consistent with the developmental regulation of NPAS3. Using luciferase reporter assays, we assessed the impact of miR-17 on NPAS3 translation and demonstrated that miR-17 alters NPAS3 biosynthesis by binding to the NPAS3 3′untranslated region (UTR). In schizophrenia prefrontal cortex, we found significant elevations in miR-17 expression. While NPAS3 mRNA was unaltered, reduced NPAS3 protein expression was detected in a subpopulation of people with schizophrenia. The reciprocal expression of NPAS3 mRNA and protein during postnatal development mediated by a schizophrenia-associated change in miR-17 suggests that there is complex control over NPAS3 synthesis in the human prefrontal cortex and that if NPAS3 is dysregulated in schizophrenia, it is not evident by large changes in NPAS3 expression. Further studies into how changes in NPAS3 or its miRNA regulator may influence the development of schizophrenia are warranted.

The truncated brain-derived neurotrophic factor (BDNF) receptors (truncated TrkB [TrkB-TK−] and sarc homology containing TrkB [TrkB-Shc]) are alternative transcripts of the full-length TrkB receptor (TrkB-TK+) that produce isoforms capable of binding to BDNF but not being able to mediate the classic neurotrophic response via tyrosine kinase signaling. We hypothesized that in the dorsolateral prefrontal cortex (DLPFC) of people with schizophrenia, truncated TrkB receptors (TK− and Shc) would be altered and may contribute to deficits in BDNF function. Using a large cohort of controls and schizophrenics (n = 72/72), we measured mRNA expression of the full-length TrkB receptor, TrkB-TK+ and the truncated TrkB receptors, TrkB-TK− and TrkB-Shc, by quantitative real-time polymerase chain reaction and protein expression by western blotting. We found highly significant increases in mRNA expression of both truncated TrkB receptor isoforms in people with schizophrenia. When we examined the full-length TrkB-TK+:truncated TrkB ratios, we observed significant decreases in schizophrenia both on the mRNA and protein level. We found a slight reduction in TrkB-TK+ mRNA and a significant reduction in TrkB-TK+ protein expression in schizophrenia, which was evident in females. No gender-specific changes were found for the truncated TrkB receptors. Diagnostic changes in TrkB-TK+ mRNA and protein may be subtle and/or gender-specific, whereas changes in TrkB-TK− and TrkB-Shc expression are robust and may generalize to both males and females with schizophrenia. Increased truncated TrkB receptors may contribute to reduced overall BDNF/tyrosine receptor kinase B (TrkB) signaling and lead to reduced neuronal plasticity in the DLPFC in schizophrenia suggesting that therapies aimed at ameliorating neurotrophin deficits may need to consider blocking excessive truncated TrkB function.

Background: Vancomycin has been the treatment standard for methicillin-resistant Staphylococcus aureus (MRSA) infections, but clinical efficacy is limited. We report outcomes of a cohort with MRSA ventilator-associated pneumonia (VAP) treated with vancomycin vs linezolid. Methods: Retrospective analysis of 113 participants with MRSA VAP confirmed by bronchoscopy who have been initiated on therapy with either vancomycin or linezolid within 24 hours after bronchoscopy and completed ≥7 days of therapy during their hospitalization from July 2003 to June 2007. The primary endpoints were hospital survival and clinical cure, defined as resolution of signs and symptoms of VAP or microbiological eradication after completion of therapy along with clinical pulmonary infection score (CPIS) ≤6 at day 7 of therapy. Results: At hospital discharge, 23/27 (85.2%) of linezolid and 72/86 (83.7%) of vancomycin recipients had survived ( P = .672). In comparison to linezolid recipients, the adjusted odds ratio (OR) for survival was 0.72 (95% confidence interval [CI]: 0.16-3.27) with vancomycin therapy. Clinical cure was achieved in 24/27 (88.9%) of linezolid and 63/86 (73.3%) of vancomycin recipients ( P = .066). Compared to linezolid recipients, the adjusted OR for clinical cure was 0.24 (95% CI: 0.05-1.10) with vancomycin therapy. Survival and clinical cure did not differ significantly between vancomycin recipients with trough level ≥15 and

In this study, we determined if estrogen receptor alpha (ERα) can interact with the full length tropomyosin receptor kinase B (TrkB-TK+), both of which are implicated in schizophrenia pathogenesis. Using neuronal (SHSY5Y) and non-neuronal (CHOK1) cell-lines, we showed that TrkB-TK+ can increase transcription at estrogen response elements (EREs) with and without exogenous estrogen treatment. In the presence of estrogen, TrkB-TK+ further potentiated the effect of estrogen stimulation on ERα-mediated transcription. This synergistic effect of TrkB-TK+ on ERα-mediated transcription was not due to direct effects of TrkB-TK+ in the nucleus, but occurred through cytoplasmic signaling of TrkB-TK+ via the MAPK/ERK pathway to phosphorylate ERα, leading to an induction in ERα-mediated transcription. When we examined the PI3K/AKT pathway, we found that PI3K/AKT activity constitutively inhibited baseline transcription at EREs. Furthermore, we showed that signaling via PI3K/AKT inhibited TrkB-TK+-dependent transcriptional potentiation at EREs. Our findings suggest that TrkB-TK+-linked second messenger signaling pathways can reciprocally regulate ERα-mediated transcription at EREs. Considering that both ERα and TrkB-TK+ expression are reduced in schizophrenia, our findings suggest that dysfunction in TrkB-TK+ signaling may occur upstream of, or in conjunction with a dysfunction in ERα, and that transcriptional regulation by ERα may be decreased by reductions in TrkB-TK+.

Apolipoprotein D (apoD) is a lipid binding protein expressed in the brain where its function is largely unknown. Based on changes in lipid metabolism and deposition that occur in the human brain during postnatal development, we investigated changes in apoD expression in the prefrontal cortex in 69 normal cases ranging in age from 40 days to 49 years utilizing gene microarray, quantitative PCR and western blotting methods. In contrast to the high expression of apolipoprotein E (APOE), low-density lipoprotein receptor-related protein 8 (LRP8) and 3-hydroxy-3-methyl-glutaryl-CoA reducatase (HMGCR) (genes that play a role in lipid-related pathways in brain development) early in life, apoD expression was low in neonates and increased in expression throughout life resulting in six- to eight-fold higher levels at the mRNA and protein levels in adults. Recent studies suggest that apoD has a novel antioxidant function in the brain and we found that the increased apoD expression throughout development and into adulthood was correlated with the expression of antioxidant genes superoxide dismutase 1 (SOD1) and glutathione peroxidase 3 (GPX3) as well as proteins that were modified by the lipid peroxidation end-product 4-hydroxynonenal. These studies reveal that apoD expression is increased throughout life in the human prefrontal cortex and that this is correlated with genetic and biochemical markers of oxidative stress.

The ATP-binding cassette transporters, ABCA1 and ABCG1, are LXR-target genes that participate in the removal of cholesterol from lipid-laden macrophages, a crucial anti-atherogenic mechanism. Statins are currently the most efficacious therapy for the treatment of hypercholesterolemia and cardiovascular disease. We and others have shown that statins decrease ABCA1 and ABCG1 expression as well as cholesterol efflux from human macrophages. However, other studies have reported that statins produce no change, or even a modest increase in these variables. In an attempt to reconcile these conflicting reports, we investigated how the effect of statins on transcription of ABCA1 and ABCG1 is modulated by cellular cholesterol status and the extent of macrophage differentiation. We showed that supplementing human macrophages with cholesterol reversed the statin-mediated down-regulation of ABC transporter expression whereas depletion of cellular cholesterol tended to accentuate the statin effect. Down-regulation of ABC transporter expression was more pronounced with increased macrophage differentiation status and already evident at statin concentrations equivalent to those present in plasma. Addition of LXR agonists, which are currently on trial as anti-atherogenic agents, reversed the effects on ABC transporter expression while PPAR alpha and PPAR gamma agonists did not. The significance of these results in light of current and future combination therapies is discussed.

Certain oxysterols, when added to cultured cells, are potent regulators of cholesterol homeostasis, decreasing cholesterol synthesis and uptake and increasing cholesterol efflux. However, very little is known about whether or not endogenous oxysterol(s) plays a significant role in cholesterol homeostasis. 24(S),25-Epoxycholesterol (24,25EC) is unique among oxysterols in that it is produced in a shunt of the mevalonate pathway which also produces cholesterol. We investigated the role of endogenously produced 24,25EC using a novel strategy of overexpressing the enzyme 2,3-oxidosqualene cyclase in Chinese hamster ovary cells to selectively inhibit the synthesis of this oxysterol. First, loss of 24,25EC decreased expression of the LXR target gene, ABCA1, substantiating its role as an endogenous ligand for LXR. Second, loss of 24,25EC increased acute cholesterol synthesis, which was rationalized by a concomitant increase in HMG-CoA reductase gene expression at the level of SREBP-2 processing. Therefore, in the absence of 24,25EC, fine-tuning of the acute regulation of cholesterol homeostasis is lost, supporting the hypothesis that 24,25EC functions to protect the cell against the accumulation of newly synthesized cholesterol.

Goal: To examine the relationship between mycophenolic acid (MPA) area under the concentration-time curve (AUC) and clinical outcomes in adult kidney transplant recipients.Methods: Forty-nine patients receiving mycophenolate mofetil (MMF) (0.5 - 1g twice daily) and either cyclosporine or tacrolimus co-therapy were recruited. MPA concentration measurements were made at pre-dose, 1, 3 and 6 hours following MMFadministration on day 5 post-transplant. MPA AUC0-12 was estimated using a limited sampling equation which provides estimates with good correlation (r2= 0.836) to full 14 time-point AUC measures1. Patient medical records were reviewed for episodes of rejection, leucopenia and thrombocytopenia in the first 3 months after transplantation. Differences between MPA apparent clearance (CL/F) (calculated as: Dose/AUC0-12) in patients with and without rejection and hematological toxicity were compared using an unpaired t-test or Mann-Whitney U test depending on whether the data were normally distributed.Results: MPA CL/F on day 5 post-transplant ranged from 9.8 to 53.9 L/h (median: 33.3 L/h). MPA CL/F was significantly higher in patients receiving cyclosporine compared to tacrolimus (mean 6 SEM; 34.7 6 1.3 L/h versus 28.2 6 3.4 L/h respectively, p=0.04). Two patients experienced biopsyproven acute rejection of grade 2A or above and 3 had borderline changes suspicious of rejection. There was no significant difference in MPA CL/F between patients who did and did not experience definitive or possible rejection. MPA CL/F was significantly lower in the seven patients who experienced leucopenia (WBC , 4.0 x 109 L-1) compared to those who did not (25.1 6 4.7 L/h versus 34.3 6 1.3 L/h respectively (p= 0.007). There was no significant difference in MPA CL/F between the six patients who experienced thrombocytopenia (PBC , 140 x 109 L-1) and the patients who did not.Conclusion: Estimation of MPA CL/F in the first week post-transplant identified patients whowere more likely to experience leucopenia in this study.

CYP27A1 (sterol 27-hydroxylase) catalyses an important sterol elimination pathway in the human macrophage, and consequently may protect against atherosclerosis. We studied the expression and regulation of CYP27A1 in a human macrophage-like cell-line, THP-1, and primary HMDMs (human monocyte-derived macrophages). In both macrophage cell types, we found that CYP27A1 expression is independent of cellular cholesterol levels and of LXR (liver X receptor)-dependent control of transcription. However, the RXR (retinoid X receptor) ligand, 9-cis-retinoic acid, upregulates CYP27A1 expression. Of the RXR heterodimeric partners tested, PPAR (peroxisome-proliferator-activated receptor) γ ligands significantly increased CYP27A1 mRNA levels. Its reversal by a PPARγ antagonist demonstrated the specificity of this effect. Interestingly, HMDMs express markedly higher levels of CYP27A1 than THP-1 macrophages, and this difference was reflected in both protein levels and enzyme activities between the two cell types. In conclusion, stimulation of CYP27A1 by PPARγ may represent a key previously unrecognized mechanism by which PPARγ protects against atherosclerosis.

Objective— Cholesterol efflux from macrophages in the artery wall, a key cardioprotective mechanism, is largely coordinated by the nuclear oxysterol-activated liver X receptor, LXRα. We investigated the effect of statins on LXR target gene expression and cholesterol efflux from human macrophages. Methods and Results— In human macrophages (THP-1 cell line and primary cells), the archetypal statin, compactin, greatly reduced mRNA levels of 2 LXR target genes, ABCA1 and ABCG1 mRNA, as well as decreased cholesterol efflux. Commonly prescribed statins also downregulated LXR target gene expression in THP-1 cells. We provide several lines of evidence indicating that statins decrease expression of LXR target genes by inhibiting the synthesis of an oxysterol ligand for LXR, 24( S ),25-epoxycholesterol. When THP-1 cells were cholesterol-loaded via incubation with acetylated low-density lipoprotein, synthesis of 24( S ),25-epoxycholesterol was greatly reduced and the downregulatory effect of compactin on ABCA1 mRNA levels and cholesterol efflux was lost. Conclusions— Our results suggest that statins may downregulate cholesterol efflux from nonloaded human macrophages by inhibiting synthesis of an oxysterol ligand for LXR. Further work is needed to determine how relevant our observations are to arterial foam cells in vivo.

Tropomyosin receptor kinase B (TrkB) is best known as the receptor for brain-derived neurotrophic factor (BDNF). In humans, three major isoforms of TrkB, the full-length receptor (TrkB-TK+) and two C-terminal truncated receptors (TrkB-TK- and TrkB-Shc) are expressed in various tissues. In comparison to TrkB-TK+ and TrkB-TK-, TrkB-Shc is less well characterized. In this study, we analyzed the biological function of the TrkB-Shc receptor in response to exogenous BDNF treatment. In experiments transiently overexpressing TrkB-Shc in CHOK1 cells, we found that TrkB-Shc protein levels were rapidly decreased when cells were exposed to exogenous BDNF. When we assessed the functional impact of TrkB-Shc on TrkB-TK+ activity, we found that phosphorylated TrkB-TK+ protein levels were significantly decreased in the presence of TrkB-Shc and moreso following BDNF exposure. Interestingly, while the reduction of phosphorylated TrkB-TK+ protein was more pronounced in the presence of TrkB-Shc following BDNF exposure, the stability of TrkB-Shc protein itself was increased. Our findings suggest that cells may increase TrkB-Shc protein levels in response to exogenous BDNF exposure to regulate TrkB-TK+ activity by increasing degradation of activated receptor complexes as a means to prevent overactivation or inappropriate temporal and spatial activation of BDNF/TrkB-TK+ signaling.

Dysregulation in brain-derived neurotrophic factor (BDNF)/full-length TrkB (TrkB-TK+) signaling is implicated in promoting neurodegeneration in Alzheimer's disease (AD). BDNF/TrkB-TK+ signaling can be modulated by the presence of truncated TrkB isoforms (TrkB-TK-, TrkB-Shc). All TrkB isoforms are encoded by different alternative transcripts. In this study, we assessed if expression of the three main TrkB alternative transcripts, TrkB-TK+, TrkB-TK-, and TrkB-Shc are altered in AD. Using a cohort of control and AD brains (n=29), we surveyed the hippocampus, temporal cortex, occipital cortex, and cerebellum and found specific increases in TrkB-Shc, a neuron-specific transcript, in the AD hippocampus. No significant changes were detected in TrkB-TK+ and TrkB-TK- transcript levels in AD in any brain region examined. Corresponding changes in truncated TrkB protein levels were found in the hippocampus, although a significant increase in the temporal cortex was also observed. Our findings suggested that neuron-specific changes in TrkB may be occurring in AD; thus, we determined whether TrkB-Shc expression could be modulated by amyloid beta 1-42 (Aβ(42)). We found increased TrkB-Shc mRNA levels in differentiated SHSY5Y neuronal cell-lines exposed to fibril-containing Aβ(42) preparations. When we assessed the cellular impact of increased TrkB-Shc, we found co-localization between TrkB-Shc and TrkB-TK+. Interestingly, TrkB-Shc overexpression selectively attenuated BDNF/TrkB-TK+-mediated signaling via the mitogen-activated protein kinase kinase (MEK) pathway, but not the protein kinase B pathway. In AD, MEK signaling is increased in vulnerable neurons and linked to abnormal phosphorylation of cytoskeletal proteins. Altogether, our findings suggest that elevated TrkB-Shc expression in AD may function as a compensatory response in neurons in AD to promote survival.

The glucocorticoid receptor (GR) has a critical role in determining the brain's capacity to respond to stress, and has been implicated in the pathogenesis of psychiatric illness. We hypothesized that key changes in cortical GR occur during adolescence and young adulthood, at a time when individuals are at increased risk of developing schizophrenia, bipolar disorder and major depression. We investigated the mRNA and protein expression of GR in the dorsolateral prefrontal cortex across seven developmental time points from infancy to adulthood. GR mRNA expression, determined by microarray and quantitative real-time PCR, was lowest in neonates and peaked around young adulthood. Western blotting revealed two dynamic patterns of GRα protein expression across the lifespan, with N-terminal variants displaying differing unique patterns of abundance. GRα-A and a 67-kDa GRα isoform mirrored mRNA trends and peaked in toddlers and late in adolescence, whereas a 40-kDa isoform, very likely a GRα-D variant, peaked in neonates and decreased across the lifespan. GRα protein was localized to pyramidal neurons throughout life and most strikingly in young adulthood, but to white matter astrocytes only in neonates and infants (

The brain-derived neurotrophic factor (BDNF) gene contains multiple 5' promoters which generate alternate transcripts. Previously, we found that pan-BDNF mRNA and protein are reduced in the dorsolateral prefrontal cortex (DLPFC) from patients with schizophrenia. In this study, we determined which of the four most abundant and best characterized BDNF alternate transcripts, I-IX, II-IX, IV-IX, and VI-IX are altered in schizophrenia. Using a cohort from the NIMH, USA, we found that BDNF II-IX mRNA was significantly reduced in the DLPFC of patients with schizophrenia, and we replicated this finding using a second cohort from Sydney, Australia. Moreover, we show that BDNF protein expression [including prepro ( approximately 32 kDa), pro ( approximately 28 kDa) and mature ( approximately 14 kDa) BDNF] is reduced in the DLPFC of patients with schizophrenia. We next determined the regional specificity of the BDNF mRNA reduction by measuring BDNF transcripts in the parietal cortex and hippocampus and found no significant changes. The effect of antipsychotics on BDNF alternate transcript expression was also examined and we found no relationship between BDNF mRNA expression and antipsychotic use. As schizophrenic patients are often prescribed antidepressants which can up-regulate expression of BDNF, we investigated the relationship between antidepressant treatment and BDNF transcript expression. All four BDNF transcripts were significantly up-regulated in schizophrenic patients treated with antidepressants. Moreover, we found significant reductions in BDNF transcripts II-IX and IV-IX in the parietal cortex and VI-IX in the hippocampus of patients with schizophrenia who did not have a history of treatment with antidepressants. This suggests that down-regulation of at least one out of four major BDNF transcripts occurs in various brain regions of patients with schizophrenia, particularly in the DLPFC which appears to have the most robust BDNF deficit in schizophrenia.

In this study, we determined when and through which promoter brain-derived neurotrophic factor (BDNF) transcription is regulated during the protracted period of human frontal cortex development. Using quantitative real-time polymerase chain reaction, we examined the expression of the four most abundant alternative 5' exons of the BDNF gene (exons I, II, IV, and VI) in RNA extracted from the prefrontal cortex. We found that expression of transcripts I-IX and VI-IX was highest during infancy, whereas that of transcript II-IX was lowest just after birth, slowly increasing to reach a peak in toddlers. Transcript IV-IX was significantly upregulated within the first year of life, and was maintained at this level until school age. Quantification of BDNF protein revealed that levels followed a similar developmental pattern as transcript IV-IX. In situ hybridization of mRNA in cortical sections showed the highest expression in layers V and VI for all four BDNF transcripts, whereas moderate expression was observed in layers II and III. Interestingly, although low expression of BDNF was observed in cortical layer IV, this BDNF mRNA low-zone decreased in prominence with age and showed an increase in neuronal mRNA localization. In summary, our findings show that dynamic regulation of BDNF expression occurs through differential use of alternative promoters during the development of the human prefrontal cortex, particularly in the younger age groups, when the prefrontal cortex is more plastic.

Aim The effects of 24(S),25-epoxycholesterol (24,25EC) on aspects of cholesterol homeostasis is well-documented. When added to cells, 24,25EC decreases cholesterol synthesis and up-regulates cholesterol efflux genes, including ABCA1. Synthesis of 24,25EC occurs in a shunt of the mevalonate pathway which also produces cholesterol. Therefore, 24,25EC synthesis should be subject to the same negative feedback regulation as cholesterol synthesis. To date, no role has been ascribed to 24,25EC in light of the fact that increased accumulation of cholesterol should decrease formation of this oxysterol through feedback inhibition. This leads to the intriguing paradox: why inhibit production of an apparently important regulator of cholesterol homeostasis when it is needed most? Methods We used a combination of pharmacological and genetic approaches in Chinese Hamster Ovary cell-lines to investigate this paradox. Endogenous synthesis of 24,25EC was manipulated using partial inhibition of the enzyme, Oxidosqualene Cyclase. Changes in cholesterol and 24,25EC synthesis were determined using metabolic labelling with [1-14C]-acetate, thin-layer chromatography and phosphorimaging. Transcriptional effects mediated via SREBP and LXR were analysed by luciferase reporter assays. Results We showed that cholesterol addition to cells lead to a rapid and preferential inhibition of 24,25EC synthesis. Addition of 24,25EC resulted in parallel inhibition of 24,25EC and cholesterol synthesis. Furthermore, we used a variety of approaches to examine the relationship between cholesterol and 24,25EC synthesis, including cell-lines with different rates of cholesterol synthesis, varying cholesterol synthetic rates by pre-treatment with a statin, or lipoprotein cholesterol loading of macrophages. In all cases, we showed that 24,25EC synthesis faithfully tracked cholesterol synthesis. Moreover, changes in 24,25EC synthesis exerted downstream effects, reducing SREBP transcriptional activity whilst increasing ABCA1 and LXR transcriptional activity. Conclusion Our results show that 24,25EC synthesis parallels cholesterol synthesis, consistent with this oxysterol functioning as a safety valve to protect against the accumulation of newly-synthesised cholesterol (as opposed to exogenously-derived cholesterol). Considering that 24,25EC is capable of being produced in all cholesterogenic cells, we propose that production of 24,25EC may represent a ubiquitous defence mechanism.