Single-Cell Analyses Offer Insights into the Different Remodeling Programs of Arteries and Veins

Arteries and veins develop different types of occlusive diseases and respond differently to injury. The biological reasons for this discrepancy are not well understood, which is a limiting factor for the development of vein-targeted therapies. This study contrasts human peripheral arteries and veins at the single-cell level, with a focus on cell populations with remodeling potential. Upper arm arteries (brachial) and veins (basilic/cephalic) from 30 organ donors were compared using a combination of bulk and single-cell RNA sequencing, proteomics, flow cytometry, and histology. The cellular atlases of six arteries and veins demonstrated a 7.8× higher proportion of contractile smooth muscle cells (SMCs) in arteries and a trend toward more modulated SMCs. In contrast, veins showed a higher abundance of endothelial cells, pericytes, and macrophages, as well as an increasing trend in fibroblasts. Activated fibroblasts had similar proportions in both types of vessels but with significant differences in gene expression. Modulated SMCs and activated fibroblasts were characterized by the upregulation of MYH10, FN1, COL8A1, and ITGA10. Activated fibroblasts also expressed F2R, POSTN, and COMP and were confirmed by F2R/CD90 flow cytometry. Activated fibroblasts from veins were the top producers of collagens among all fibroblast populations from both types of vessels. Venous fibroblasts were also highly angiogenic, proinflammatory, and hyper-responders to reactive oxygen species. Differences in wall structure further explain the significant contribution of fibroblast populations to remodeling in veins. Fibroblasts are almost exclusively located outside the external elastic lamina in arteries, while widely distributed throughout the venous wall. In line with the above, ECM-targeted proteomics confirmed a higher abundance of fibrillar collagens in veins vs. more basement ECM components in arteries. The distinct cellular compositions and transcriptional programs of reparative populations in arteries and veins may explain differences in acute and chronic wall remodeling between vessels. This information may be relevant for the development of antistenotic therapies.

ABCA1 deficiency contributes to podocyte pyroptosis priming via the APE1/IRF1 axis in diabetic kidney disease

Decreased ATP Binding Cassette Transporter A1 (ABCA1) expression and caspase-4-mediated noncanonical inflammasome contribution have been described in podocytes in diabetic kidney disease (DKD). To investigate a link between these pathways, we evaluated pyroptosis-related mediators in human podocytes with stable knockdown of ABCA1 (siABCA1) and found that mRNA levels of IRF1, caspase-4, GSDMD, caspase-1 and IL1β were significantly increased in siABCA1 compared to control podocytes and that protein levels of caspase-4, GSDMD and IL1β were equally increased. IRF1 knockdown in siABCA1 podocytes prevented increases in caspase-4, GSDMD and IL1β. Whereas TLR4 inhibition did not decrease mRNA levels of IRF1 and caspase-4, APE1 protein expression increased in siABCA1 podocytes and an APE1 redox inhibitor abrogated siABCA1-induced expression of IRF1 and caspase-4. RELA knockdown also offset the pyroptosis priming, but ChIP did not demonstrate increased binding of NFκB to IRF1 promoter in siABCA1 podocytes. Finally, the APE1/IRF1/Casp1 axis was investigated in vivo. APE1 IF staining and mRNA levels of IRF1 and caspase 11 were increased in glomeruli of BTBR ob/ob compared to wildtype. In conclusion, ABCA1 deficiency in podocytes caused APE1 accumulation, which reduces transcription factors to increase the expression of IRF1 and IRF1 target inflammasome-related genes, leading to pyroptosispriming.

Empagliflozin reduces podocyte lipotoxicity in experimental Alport syndrome

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are anti-hyperglycemic agents that prevent glucose reabsorption in proximal tubular cells. SGLT2i improves renal outcomes in both diabetic and non-diabetic patients, indicating it may have beneficial effects beyond glycemic control. Here, we demonstrate that SGLT2i affects energy metabolism and podocyte lipotoxicity in experimental Alport syndrome (AS). In vitro, we found that the SGLT2 protein was expressed in human and mouse podocytes to a similar extent in tubular cells. Newly established immortalized podocytes from Col4a3 knockout mice (AS podocytes) accumulate lipid droplets along with increased apoptosis when compared to wild-type podocytes. Treatment with SGLT2i empagliflozin reduces lipid droplet accumulation and apoptosis in AS podocytes. Empagliflozin inhibits the utilization of glucose/pyruvate as a metabolic substrate in AS podocytes but not in AS tubular cells. In vivo, we demonstrate that empagliflozin reduces albuminuria and prolongs the survival of AS mice. Empagliflozin-treated AS mice show decreased serum blood urea nitrogen and creatinine levels in association with reduced triglyceride and cholesterol ester content in kidney cortices when compared to AS mice. Lipid accumulation in kidney cortices correlates with a decline in renal function. In summary, empagliflozin reduces podocyte lipotoxicity and improves kidney function in experimental AS in association with the energy substrates switch from glucose to fatty acids in podocytes.

Measuring health expectancy in the European Union

Background

Healthy life expectancy (HLE) is a population health measure that combines mortality and morbidity, which can be calculated using different methods. In this study, we aimed to assess the correlation, reliability and (dis)agreement between two estimates monitored in the European Union (EU), that is, the European Commission's HLE based on self-perceived health (SPH-HLE) and the Institute for Health Metrics and Evaluation's HLE based on disability weight (DW-HLE), by sex, and comparing these results with LE and proportion of life spent in good health (%GH).

Methods

We performed a retrospective study in the EU28 countries, between 2010 and 2017. The HLE methods differ in definition, measurement and valuation of health states. While SPH-HLE relies directly on one question, DW-HLE relies on epidemiological data adjusted for DW. Spearman's r, intraclass correlation coefficient, information-based measure of disagreement and Bland-Altman plots were used to assess reliability, correlation and disagreement in HLE resulting from both methods and in LE or %GH measured by both institutions.

Results

Correlation and reliability between SPH-HLE and DW-HLE were good (better for males), with low disagreement, and were even better for LE between both institutions. The HLE Bland-Altman plots suggest a variability range of approximately 6 years for both sexes, higher for females. There was also an increasing HLE difference between methods with higher average HLE for both sexes.

Conclusions

We showed wide variations between both methods with a clear and different high impact on female and male HLE, showing a tendency for countries with higher health expectancies to yield larger gaps between SPH-HLE and DW-HLE.

Acknowledgements: This presentation was supported by National Funds through FCT - Fundação para a Ciência e a Tecnologia,I.P., within CINTESIS, R&D Unit (reference UIDP/4255/2020)

Key messages

• Different methods for evaluating health expectancy lead to significantly different results.

• There is a systematic tendency with countries with higher health expectancies to yield larger gaps between SPH-HLE and DW-HLE.

New proposed measures to evaluate contact tracing effectiveness

Issue/problem

Contact tracing is an important and widely used method to control transmission of communicable diseases. The COVID-19 pandemic presented a new and big challenge with a high number of confirmed cases and contacts and subsequent high burden on contact tracing activities. Naturally, the effectiveness of such interventions needs to be assessed, and appropriate measures are still rather underdeveloped.

Description of the problem

We propose two new measures for assessing contact tracing effectiveness: “number needed to quarantine” (NNQ), which is the number of quarantined person-days needed to prevent one infectious person-day, and the proportion of infectious days prevented by the quarantined (PPID). We have applied these measures to assess COVID-19 contact tracing effectiveness in COVID-19 confirmed cases diagnosed between July and mid-September 2020 in a local Public Health Unity in the Northern region of Portugal (Espinho/Gaia). For robustness checks and accounting for the uncertainty of the infectiousness period, we used three different scenarios.

Results

Depending on the infectiousness period considered, we have found a NNQ between 19.8 and 41.8 and a PPID between 19.7% and 38.2%. Contact tracing effectiveness was higher for some specific groups such as cohabitants and symptomatic contacts. Effectiveness also decreased with the increasing time from diagnosis or symptom onset to contact isolation

Lessons

NNQ and PPID are straightforward and easy to use measures to evaluate contact tracing effectiveness in communicable diseases. Although this example focuses in the COVID-19 pandemic at a local setting, these measures can also be used for different communicable diseases and at different levels. This assessment step can be important for priority setting of transmission control activities but also on a health management perspective.

Key messages

• New measures to evaluate contact tracing effectiveness are proposed: “number needed to quarantine” and “proportion of prevented infectious days”.

• These measures allow the identification of priority groups that must be quarantined, as well as time periods of intervention, for better transmission control.

What does it mean to age in good health? An analysis of Time Use Survey data

Background

While there is intrinsic value of ageing in good health, there is little evidence of how the daily lives of older people differ depending on their health status.

Methods

We use Time Use Survey data from the United Kingdom to assess how people at different ages spend their time, conditional on their self-reported health.

Results

While results are preliminary, we find stark differences between people's time use dependent on their health. For example, older people who report good health are more likely than comparable older people to engage in paid work, volunteer, and participate in leisure activities.

Conclusions

There are many benefits to supporting healthy ageing. By considering how time spent differs between those in good and poor health and attributing value to that time, one can take a more holistic perspective when conducting cost-benefit analysis of policy interventions.

Compounds targeting OSBPL7 increase ABCA1-dependent cholesterol efflux preserving kidney function in two models of kidney disease

Impaired cellular cholesterol efflux is a key factor in the progression of renal, cardiovascular, and autoimmune diseases. Here we describe a class of 5-arylnicotinamide compounds, identified through phenotypic drug discovery, that upregulate ABCA1-dependent cholesterol efflux by targeting Oxysterol Binding Protein Like 7 (OSBPL7). OSBPL7 was identified as the molecular target of these compounds through a chemical biology approach, employing a photoactivatable 5-arylnicotinamide derivative in a cellular cross-linking/immunoprecipitation assay. Further evaluation of two compounds (Cpd A and Cpd G) showed that they induced ABCA1 and cholesterol efflux from podocytes in vitro and normalized proteinuria and prevented renal function decline in mouse models of proteinuric kidney disease: Adriamycin-induced nephropathy and Alport Syndrome. In conclusion, we show that small molecule drugs targeting OSBPL7 reveal an alternative mechanism to upregulate ABCA1, and may represent a promising new therapeutic strategy for the treatment of renal diseases and other disorders of cellular cholesterol homeostasis.

APOL1 risk variants affect podocyte lipid homeostasis and energy production in focal segmental glomerulosclerosis

Lipotoxicity was recently reported in several forms of kidney disease, including focal segmental glomerulosclerosis (FSGS). Susceptibility to FSGS in African Americans is associated with the presence of genetic variants of the Apolipoprotein L1 gene (APOL1) named G1 and G2. If and how endogenous APOL1 may alter mitochondrial function by the modifying cellular lipid metabolism is unknown. Using transgenic mice expressing the APOL1 variants (G0, G1 or G2) under endogenous promoter, we show that APOL1 risk variant expression in transgenic mice does not impair kidney function at baseline. However, APOL1 G1 expression worsens proteinuria and kidney function in mice characterized by the podocyte inducible expression of nuclear factor of activated T-cells (NFAT), which we have found to cause FSGS. APOL1 G1 expression in this FSGS-model also results in increased triglyceride and cholesterol ester contents in kidney cortices, where lipid accumulation correlated with loss of renal function. In vitro, we show that the expression of endogenous APOL1 G1/G2 in human urinary podocytes is associated with increased cellular triglyceride content and is accompanied by mitochondrial dysfunction in the presence of compensatory oxidative phosphorylation (OXPHOS) complexes elevation. Our findings indicate that APOL1 risk variant expression increases the susceptibility to lipid-dependent podocyte injury, ultimately leading to mitochondrial dysfunction.

Primary care organizational model mix and avoidable hospitalization: an ecological study in Portugal

Background

In Portugal, there are different organizational models in primary health care (PHC), mainly regarding the payment scheme. USF-B is the only type with financial incentives to the professional (pay-for-performance). Our goal was to assess the relationship between groups of primary healthcare centres (ACES) with higher proportion of patients within USF-B model and the rate of avoidable hospitalizations, as proxy of primary care quality.

Methods

We conducted a cross-sectional study considering the 55 ACES from mainland Portugal, in 2017. We used data from public hospitalizations to calculate the prevention quality indicator (avoidable hospitalizations) adjusted for age and sex, using direct standardization. The main independent variable was the proportion of patients in one ACES registered in the USF-B model. Unemployment rate, proportion of patients with family doctor and presence of Local Health Unit (different organization model) within ACES were also considered. The association was assessed by means of a linear regression model.

Results

Age-sex adjusted PQI value varied between 490 and 1715 hospitalizations per 100,000 inhabitants across ACES. We observed a significant effect of the proportion of patients within USF-B in the crude PQI rate (p = 0.001). However, using the age-sex adjusted PQI, there was not a statistical significant association (p = 0.504). This last model was also adjusted for confounding variables and the association remains non-significant (p = 0.865).

Conclusions

Our findings suggest that, when adjusting for age and sex, there is no evidence that ACES with more patients enrolled in a pay-for-performance model is associated with higher quality of PHC (using avoidable hospitalizations as proxy). Further studies addressing individual data should be performed.

This work was financed by FEDER funds through the COMPETE 2020 - POCI, and by Portuguese funds through FCT in the framework of the project POCI-01-0145-FEDER-030766 “1st.IndiQare”.

Key messages

Adjusting PQI to sex and age seems to influence its value more than the type of organizational model of primary health care. Groups of primary healthcare centres with more units under the pay-for-performance scheme was not associated with different rate of avoidable hospitalizations.

Efficiency of groups of primary healthcare centres: a frontier analysis of primary care in Portugal

Background

Primary health care (PHC) is the cornerstone of several health systems. The Portuguese PHC is organized in five mainland regions (ARS), that oversee 55 local groups of primary healthcare centres (ACES). We assessed the efficiency of all 55 ACES in mainland Portugal, as well as organizational and socioeconomic determinants of the efficiency.

Methods

A cross-sectional non-parametric frontier analysis was performed for 2017. The first model included two inputs (i.e. number of physicians and number of nurses) and a single output (i.e. number of PHC visits), while the second model included an additional output, i.e. Prevention Quality Indicator (PQI) overall composite (avoidable hospitalizations) adjusted for age and sex - as undesirable output. In a second stage, a (multivariate) Tobit regression was used to assess organizational and socioeconomic determinants of efficiency.

Results

In the first model, only 8 ACES (14.5%) were on the efficiency frontier, while 25 ACES should readjust their human resource balance. In the second model, 9 ACES (16.4%) were considered efficient. When considering quality, one ACES previously considered inefficient moved to the frontier and two ACES lost their benchmark position. The second-stage analysis indicates that groups with a higher proportion of PHC units with pay-for-performance incentives were associated with higher efficiency.

Conclusions

Most ACES have the potential to improve their production levels., A better management of human resources can contribute to improve overall efficiency. ACES with a higher proportion of units with pay-for-performance schemes seem to be more efficient. These findings contribute to the evaluation of policies to integrate and scale up PHC services locally, such as the recent primary care networks in the NHS UK.

This work was financed by FEDER funds through the COMPETE 2020 - POCI, and by Portuguese funds through FCT in the framework of the project POCI-01-0145-FEDER-030766 “1st.IndiQare”.

Key messages

Most Portuguese ACES have the potential to improve their outputs given their current level of human resources. Local groups that aggregate more PHC units with pay-for-performance schemes are associated with high efficiency.

Sterol-O-acyltransferase-1 has a role in kidney disease associated with diabetes and Alport syndrome

Defective cholesterol metabolism primarily linked to reduced ATP-binding cassette transporter A1 (ABCA1) expression is closely associated with the pathogenesis and progression of kidney diseases, including diabetic kidney disease and Alport Syndrome. However, whether the accumulation of free or esterified cholesterol contributes to progression in kidney disease remains unclear. Here, we demonstrate that inhibition of sterol-O-acyltransferase-1 (SOAT1), the enzyme at the endoplasmic reticulum that converts free cholesterol to cholesterol esters, which are then stored in lipid droplets, effectively reduced cholesterol ester and lipid droplet formation in human podocytes. Furthermore, we found that inhibition of SOAT1 in podocytes reduced lipotoxicity-mediated podocyte injury in diabetic kidney disease and Alport Syndrome in association with increased ABCA1 expression and ABCA1-mediated cholesterol efflux. In vivo, Soat1 deficient mice did not develop albuminuria or mesangial expansion at 10-12 months of age. However, Soat1 deficiency/inhibition in experimental models of diabetic kidney disease and Alport Syndrome reduced cholesterol ester content in kidney cortices and protected from disease progression. Thus, targeting SOAT1-mediated cholesterol metabolism may represent a new therapeutic strategy to treat kidney disease in patients with diabetic kidney disease and Alport Syndrome, like that suggested for Alzheimer's disease and cancer treatments.

To be or not to be hospitalised with tuberculosis in Portugal

SETTING: In Portugal, as in other countries, tuberculosis (TB) is considered a disease that should be managed on an ambulatory basis. However, hospitalisation remains important to manage some at-risk groups and complications.OBJECTIVE: To identify the possible risk factors associated with hospitalisations in TB patients in Portugal.DESIGN: Data extraction through two national databases (one for registration of TB cases and the other with hospitalisation information in public health facilities) between 2007 and 2013. Univariate and multivariate analysis of demographic and clinical variables was performed.RESULTS: We identified 4421 hospitalisations. Chronic diseases, cancer, substance abuse, a higher social/economic risk, extra-pulmonary TB, lung cavitary disease and previous uncompleted treatment were more frequent among hospitalised patients. Human immunodeficiency virus coinfection, cancer, alcohol abuse, extra-pulmonary TB and uncompleted previous TB treatment were the most important predictors of hospitalisation with TB. The hospitalisation rate among TB patients in Portugal was lower when compared with other countries with lower and higher incidences.CONCLUSION: Immune dysfunctions and progression of chronic diseases are associated with more severe forms of TB and frequent adverse effects which can be sufficiently severe to necessitate hospital admission. Despite having an intermediate TB incidence, the hospitalisation rate in Portugal is not higher than that of other countries.

Time trends of primary care quality across Portuguese regions: using prevention quality indicators

Background

Primary care quality is one of the main dimensions of primary care performance and can be evaluated by several methods, e.g. studying hospitalizations for conditions that could be treated, or less severe, if appropriately managed in primary care. Accordingly, the Agency for Healthcare Research and Quality (AHRQ) developed prevention quality indicators (PQIs). In this study, we aimed to compare PQIs and their time trends across Portuguese regions.

Methods

We performed a retrospective study, using all adult public hospital discharges in mainland Portugal, between 2011 and 2015. PQI rates for the overall (PQI 90) and composite indicators (i.e. 91 - acute, 92 - chronic, 93 - diabetes) were computed using AHRQ specifications. These rates were compared between the 5 Portuguese NUTS 2 regions of residence.

Results

From the total of 407,792 hospital discharges in mainland Portugal (2011-2015) 11.9% comprised the selected PQIs, the majority related the acute composite PQI, followed by the chronic composite PQI. The hospitalization rate of the overall PQI increased from 999.5 hospitalizations (2011) to 1231,0 hospitalizations/100,000 inhabitants (2015), with an increase in all NUTS 2 regions. In 2015, while Algarve and North had the lowest PQI rates, Centro and Alentejo showed the highest ones.

Conclusions

Between 2011 and 2015, there was an increasing trend of overall and composite PQI rates. Also, important differences between Portuguese regions were found that must be further studied.

The authors thank the support given by the Project ’POCI-01-0145-FEDER-030766’ (1st.IndiQare - Quality indicators in primary health care: validation and implementation of quality indicators as an assessment and comparison tool), funded by Fundação para a Ciência e a Tecnologia (FCT) and co-funded by Fundo de Desenvolvimento Regional (FEDER) through Operacional Competitividade e Internacionalização (COMPETE 2020).

Key messages

Between 2011 and 2015, overall prevention quality indicator rate increased in Portugal. There are great differences between Portuguese NUTS 2 regions regarding prevention quality indicators.

ATP-binding cassette A1 deficiency causes cardiolipin-driven mitochondrial dysfunction in podocytes

Fibroblasts from patients with Tangier disease carrying ATP-binding cassette A1 (ABCA1) loss-of-function mutations are characterized by cardiolipin accumulation, a mitochondrial-specific phospholipid. Suppression of ABCA1 expression occurs in glomeruli from patients with diabetic kidney disease (DKD) and in human podocytes exposed to DKD sera collected prior to the development of DKD. We demonstrated that siRNA ABCA1 knockdown in podocytes led to reduced oxygen consumption capabilities associated with alterations in the oxidative phosphorylation (OXPHOS) complexes and with cardiolipin accumulation. Podocyte-specific deletion of Abca1 (Abca1fl/fl) rendered mice susceptible to DKD, and pharmacological induction of ABCA1 improved established DKD. This was not mediated by free cholesterol, as genetic deletion of sterol-o-acyltransferase-1 (SOAT1) in Abca1fl/fl mice was sufficient to cause free cholesterol accumulation but did not cause glomerular injury. Instead, cardiolipin mediates ABCA1-dependent susceptibility to podocyte injury, as inhibition of cardiolipin peroxidation with elamipretide improved DKD in vivo and prevented ABCA1-dependent podocyte injury in vitro and in vivo. Collectively, we describe a pathway definitively linking ABCA1 deficiency to cardiolipin-driven mitochondrial dysfunction. We demonstrated that this pathway is relevant to DKD and that ABCA1 inducers or inhibitors of cardiolipin peroxidation may each represent therapeutic strategies for the treatment of established DKD.

DNA-Encoded Library-Derived DDR1 Inhibitor Prevents Fibrosis and Renal Function Loss in a Genetic Mouse Model of Alport Syndrome

The importance of Discoidin Domain Receptor 1 (DDR1) in renal fibrosis has been shown via gene knockout and use of antisense oligonucleotides; however, these techniques act via a reduction of DDR1 protein, while we prove the therapeutic potential of inhibiting DDR1 phosphorylation with a small molecule. To date, efforts to generate a selective small-molecule to specifically modulate the activity of DDR1 in an in vivo model have been unsuccessful. We performed parallel DNA encoded library screens against DDR1 and DDR2, and discovered a chemical series that is highly selective for DDR1 over DDR2. Structure-guided optimization efforts yielded the potent DDR1 inhibitor 2.45, which possesses excellent kinome selectivity (including 64-fold selectivity over DDR2 in a biochemical assay), a clean in vitro safety profile, and favorable pharmacokinetic and physicochemical properties. As desired, compound 2.45 modulates DDR1 phosphorylation in vitro as well as prevents collagen-induced activation of renal epithelial cells expressing DDR1. Compound 2.45 preserves renal function and reduces tissue damage in Col4a3^–/– mice (the preclinical mouse model of Alport syndrome) when employing a therapeutic dosing regime, indicating the real therapeutic value of selectively inhibiting DDR1 phosphorylation in vivo. Our results may have wider significance as Col4a3^–/– mice also represent a model for chronic kidney disease, a disease which affects 10% of the global population.

Hydroxypropyl-β-cyclodextrin protects from kidney disease in experimental Alport syndrome and focal segmental glomerulosclerosis

Studies suggest that altered renal lipid metabolism plays a role in the pathogenesis of diabetic kidney disease and that genetic or pharmacological induction of cholesterol efflux protects from the development of diabetic kidney disease and focal segmental glomerulosclerosis (FSGS). Here we tested whether altered lipid metabolism contributes to renal failure in the Col4a3 knockout mouse model for Alport Syndrome. There was an eight-fold increase in the cholesterol content in renal cortexes of mice with Alport Syndrome. This was associated with increased glomerular lipid droplets and cholesterol crystals. Treatment of mice with Alport Syndrome with hydroxypropyl-β-cyclodextrin (HPβCD) reduced cholesterol content in the kidneys of mice with Alport Syndrome and protected from the development of albuminuria, renal failure, inflammation and tubulointerstitial fibrosis. Cholesterol efflux and trafficking-related genes were primarily affected in mice with Alport Syndrome and were differentially regulated in the kidney cortex and isolated glomeruli. HPβCD also protected from proteinuria and mesangial expansion in a second model of non-metabolic kidney disease, adriamycin-induced nephropathy. Consistent with our experimental findings, microarray analysis confirmed dysregulation of several lipid-related genes in glomeruli isolated from kidney biopsies of patients with primary FSGS enrolled in the NEPTUNE study. Thus, lipid dysmetabolism occurs in non-metabolic glomerular disorders such as Alport Syndrome and FSGS, and HPβCD improves renal function in experimental Alport Syndrome and FSGS.

Abstract 3246: Pharmacologic targeting of the Hedgehog (HH) signal transduction pathway significantly suppresses growth of malignant pleural mesothelioma (MPM) and non-small cell lung cancer (NSCLC) cells in vitro

OBJECTIVE. The HH signal transduction pathway plays crucial roles in organ morphogenesis and is active during embryonic development but quiescent in terminally differentiated cells. Binding of HH ligands to PTCH1 relieves its inhibitory activity on the pathway activator SMO leading to pathway activation and upregulation of target gene expression including the transcription factor Gli1 that serves as marker of pathway activation. It is reactivated in many solid cancers including NSCLC as we have previously demonstrated and proven to be the key oncogenic driver in tumors such as skin basal cell carcinoma. The aim of this study is to determine if HH pathway regulates cell growth and survival of MPM cells and to evaluate the efficacy of pathway blockade using SMO antagonists (SMO inhibitor GDC0449 - GDC or the antifungal drug itraconazole -ITRA) or Gli inhibitors (GANT61 or the anti-leukemia drug arsenic trioxide - ATO) in suppressing the viability of not only NSCLC but also MPM cells.

METHODS. Expression of main components of HH pathway in 8 MPM cells was assessed by qRT-PCR. Suppression of HH/SMO-mediated signaling by these pathway antagonists was determined by LightII cells. Selective knockdown of SMO to inhibit HH signaling was achieved by siRNA in 3 MPM cells H2373, Gardner and H2452. Cell viability following treatments with GDC, ITRA, GANT61or ATO were evaluated in a panel of 8 MPM cells and 8 NSCLC cells using MTT assay. Apoptosis was determined by annexinV/PE staining and flow cytometry.

RESULTS. All MPM cells, similar to previously demonstrated in NSCLC cells, express varying levels of HH ligands, PTCH1, SMO with readily detectable Gli1 observed in 7/8 of MPM cells by qRT-PCR. SMO siRNA mediate 2- to 3-fold reduction of SMO and also of Gli1 gene expression by qRT-PCR, indicating significant HH pathway blockade. This was associated with 40±6% to 70±8% reduction of cell viability (p<0.01 versus non-target siRNA controls). All 4 pathway antagonists completely blocked HH activation in LightII reporter cells. Treating MPM or NSCLC cells with HH inhibitors resulted in 1.5- to 4-fold reduction of Gli1 expression. GANT61, ATO, ITRA and to a lesser degree GDC significantly suppressed viability of all cancer cells at low microM concentrations. More importantly, ITRA, ATO, GANT61 induce significant apoptosis (ranging from 30% to 60%) in representative MPM or NSCLC cells.

CONCLUSIONS. HH signaling is active in MPM and regulates cell viability. ATO and ITRA are as effective as the prototypic SMO inhibitor GDC and the Gli inhibitor GANT61 in suppressing HH signaling in MPM and NSCLC cells. Pharmaceuticals that are FDA-approved for other indications but recently found to have anti-HH activity such as ATO or ITRA may be repurposed to treat HH-dependent MPM or NSCLC cells.

Citation Format: Min You, Javier Varona Santos, David J. Robbins, Niramol Savaraj, Dao M. Nguyen. Pharmacologic targeting of the Hedgehog (HH) signal transduction pathway significantly suppresses growth of malignant pleural mesothelioma (MPM) and non-small cell lung cancer (NSCLC) cells in vitro. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3246. doi:10.1158/1538-7445.AM2013-3246

Nephrin is expressed on the surface of insulin vesicles and facilitates glucose-stimulated insulin release

OBJECTIVE

Nephrin, an immunoglobulin-like protein essential for the function of the glomerular podocyte and regulated in diabetic nephropathy, is also expressed in pancreatic beta-cells, where its function remains unknown. The aim of this study was to investigate whether diabetes modulates nephrin expression in human pancreatic islets and to explore the role of nephrin in beta-cell function.

RESEARCH DESIGN AND METHODS

Nephrin expression in human pancreas and in MIN6 insulinoma cells was studied by Western blot, PCR, confocal microscopy, subcellular fractionation, and immunogold labeling. Islets from diabetic (n = 5) and nondiabetic (n = 7) patients were compared. Stable transfection and siRNA knockdown in MIN-6 cells/human islets were used to study nephrin function in vitro and in vivo after transplantation in diabetic immunodeficient mice. Live imaging of green fluorescent protein (GFP)-nephrin-transfected cells was used to study nephrin endocytosis.

RESULTS

Nephrin was found at the plasma membrane and on insulin vesicles. Nephrin expression was decreased in islets from diabetic patients when compared with nondiabetic control subjects. Nephrin transfection in MIN-6 cells/pseudoislets resulted in higher glucose-stimulated insulin release in vitro and in vivo after transplantation into immunodeficient diabetic mice. Nephrin gene silencing abolished stimulated insulin release. Confocal imaging of GFP-nephrin-transfected cells revealed nephrin endocytosis upon glucose stimulation. Actin stabilization prevented nephrin trafficking as well as nephrin-positive effect on insulin release.

CONCLUSIONS

Our data suggest that nephrin is an active component of insulin vesicle machinery that may affect vesicle-actin interaction and mobilization to the plasma membrane. Development of drugs targeting nephrin may represent a novel approach to treat diabetes.

Clinical heterogeneity of autosomal recessive spastic paraplegias: analysis of 106 patients in 46 families

BACKGROUND

Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders characterized by progressive and predominant spasticity of the lower limbs, in which dominant, recessive, and X-linked forms have been described. While autosomal dominant HSP has been extensively studied, autosomal recessive HSP is less well known and is considered a rare condition.

OBJECTIVE

To analyze the clinical presentation in a large group of patients with autosomal recessive HSP from Portugal and Algeria to define homogeneous groups that could serve as a guide for future molecular studies.

RESULTS

Clinical features in 106 patients belonging to 46 Portuguese and Algerian families with autosomal recessive HSP are presented, as well as the results of molecular studies in 23 of these families. Five phenotypes are defined: (1) pure early-onset families, (2) pure lateonset families, (3) complex families with mental retardation, (4) complex families with mental retardation and peripheral neuropathy, and (5) complex families with cerebellar ataxia. Six additional families have specific complex presentations, each of which is unique in the present series. Pyramidal signs in the upper limbs and pes cavus are frequent findings, while pseudobulbar signs, including dysarthria, dysphagia, and brisk jaw jerks, are more frequent in the complex forms. The complex forms have a poorer prognosis, while pure forms, particularly those with early onset, are more benign. One Algerian pure early-onset kindred was linked to the locus on chromosome 8, previously reported in 4 Tunisian families. Two of the Portuguese kindreds with complex forms (one with mental retardation and the other associated with hypoplasia of the corpus callosum) showed linkage to the locus recently identified on chromosome 16.

CONCLUSIONS

Although autosomal recessive HSP represents a heterogeneous group of diseases, some phenotypes can be defined by analyzing a large group of patients. The fact that only one Algerian family was linked to chromosome 8 suggests that this is a rare localization even in kindreds with the same ethnic background. Linkage to chromosome 16 was found in 2 clinically diverse Portuguese kindreds, illustrating that this locus is also rare and may correspond to different phenotypes.

Generalized freezing in Hallervorden-Spatz syndrome: case report

We report the case of a female patient who was exhibiting slowly progressive, severe, generalized freezing of voluntary movement and disequilibrium. Brain magnetic resonance imaging showed a very low signal intensity in both pallidal nuclei, with a high signal intensity in the central portion, the so called 'eye-of-the-tiger' sign. Despite the unusual clinical features, we believe that this is a case of Hallervorden-Spatz syndrome, although without neuropathological examination we were unable to confirm the diagnosis with certainty. This case further demonstrates the complex role of the pallidum in voluntary movement.

Intravenous cyclosporine for steroid-refractory attacks of Crohn's disease. Short- and long-term results

A prospective, open trial was conducted to test whether i.v. cyclosporine was effective in the treatment of refractory Crohn's disease. Eight patients with acute steroid-refractory attacks were included. Intravenous cyclosporine, 5 mg/kg/day, was added to ongoing drug therapy. Patients who responded were then switched to oral cyclosporine for a mean 2.6-month period, and steroids were discontinued when possible. Six patients improved, with a mean latency time to onset of improvement of 9 days. Two did not improve, and both underwent urgent operation. On oral cyclosporine, five patients maintained remission and discontinued steroids, whereas one relapsed and underwent surgery. After discontinuation of oral cyclosporine, the five remaining patients relapsed, and two underwent surgery. One reversible episode of hepatobiliary toxicity and one of gastrointestinal intolerance were recorded. We conclude that i.v. cyclosporine effectively and rapidly induces improvement of acute steroid-refractory flare-ups of Crohn's disease, but after discontinuation relapse is to be expected.

Genetic heterogeneity in hypokalemic periodic paralysis (hypoPP)

Hypokalemic periodic paralysis (hypoPP) is an autosomal dominant disorder belonging to a group of muscle diseases known to involve an abnormal function of ion channels. The latter includes hypokalemic and hyperkalemic periodic paralyses, and non-dystrophic myotonias. We recently showed genetic linkage of hypoPP to loci on chromosome 1q31-32, co-localized with the DHP-sensitive calcium channel CACNL1A3. We propose to term this locus hypoPP-1. Using extended haplotypes with new markers located on chromosome 1q31-32, we now report the detailed mapping of hypoPP-1 within a 7 cM interval. Two recombinants between hypoPP-1 and the flanking markers D1S413 and D1S510 should help to reduce further the hypoPP-1 interval. We used this new information to demonstrate that a large family of French origin displaying hypoPP is not genetically linked to hypoPP-1. We excluded genetic linkage over the entire hypoPP-1 interval showing for the first time genetic heterogeneity in hypoPP.

Are the endemic motor neuron diseases of Guam really disappearing?

Death certificates were reviewed to observe trends in the number of persons on Guam reported to have chronic degenerative motor neuron diseases (amyotrophic lateral sclerosis, parkinsonism-dementia or Parkinson's disease) at the time of death. Additional data, including age and race of the deceased and the name of the certifying physician were also collected. The number of persons having been diagnosed with amyotrophic lateral sclerosis is apparently decreasing while their mean age is increasing suggesting that the etiologic agents or factors causing this disease are less prevalent on Guam today than they have been in the past. Trends with regard to parkinsonism-dementia and Parkinson's disease are less clear.