Loss of microRNA-21 protects against acetaminophen-induced hepatotoxicity in mice

Acetaminophen (APAP)-induced Acute Liver Failure (ALF) is recognized as the most common cause of ALF in Western societies. APAP-induced ALF is characterized by coagulopathy, hepatic encephalopathy, multi-organ failure, and death. MicroRNAs are small, non-coding RNAs that regulate gene expression at the post-transcriptional level. MicroRNA-21 (miR-21) is dynamically expressed in the liver and is involved in the pathophysiology of both acute and chronic liver injury models. We hypothesize that miR-21genetic ablation attenuates hepatotoxicity following acetaminophen intoxication. Eight-week old miR-21knockout (miR21KO) or wild-type (WT) C57BL/6N male mice were injected with acetaminophen (APAP, 300 mg/kg BW) or saline. Mice were sacrificed 6 or 24 h post-injection. MiR21KO mice presented attenuation of liver enzymes ALT, AST, LDH compared with WT mice 24 h post-APAP treatment. Moreover, miR21KO mice had decreased hepatic DNA fragmentation and necrosis than WT mice after 24 h of APAP treatment. APAP-treated miR21KO mice showed increased levels of cell cycle regulators CYCLIN D1 and PCNA, increased autophagy markers expression (Map1LC3a, Sqstm1) and protein (LC3AB II/I, p62), and an attenuation of the APAP-induced hypofibrinolytic state via (PAI-1) compared with WT mice 24 post-APAP treatment. MiR-21 inhibition could be a novel therapeutic approach to mitigate APAP-induced hepatotoxicity and enhance survival during the regenerative phase, particularly to alter regeneration, autophagy, and fibrinolysis. Specifically, miR-21 inhibition could be particularly useful when APAP intoxication is detected at its late stages and the only available therapy is minimally effective.

Abstract WP71: Real-world Outcomes After Carotid Artery Stenting

Carotid artery stenting (CAS) for carotid stenosis (CS) is widely performed. Randomized trials may not be reflective of real-world outcomes. We used the 2012-19 ACS-NSQIP CAS Procedure Targeted Dataset to identify the incidence and risk factors associated with periprocedural 30-day adverse events (AE). AE were categorized as follows: vascular (embolization - proximal and distal thrombosis, myocardial infarction [MI], stroke, restenosis, and TIA) , stroke/TIA alone, major (organ-space surgical site infection [SSI]), pneumonia, intubation, pulmonary embolism, post-operative ventilator use, blood transfusion, deep venous thrombosis, sepsis), minor (urinary tract infections, acute renal failure, superficial SSI). Other outcome variables were readmissions, reoperations, mortality, and non-home discharges. Multivariate logistic regression analysis, using backward stepwise model with entry and removal probabilities of p=0.05 and p=0.1. 1552 patients (median age=70 IQR 62-76) were included. 64% were male. 49% of CAS procedures were in asymptomatic patients, whereas 24% were following stroke, 16% to TIA and 8% for amaurosis fugax. 2.1% were mild (<50%) carotid stenosis, 26.6% were moderate (50%-79%) stenosis and 65.6% were severe (80%-99%) stenosis, while 2.7% were complete occlusions. Perioperative mortality was 1.9% and 10.6% were non-home discharges. 6.2% experienced vascular AE; 2.8% patients had perioperative strokes, 0.9% had TIA, 2.3% had MI, 0.7% had thrombosis, 0.4% had proximal embolization, 0.5% were restenosis, and 0.6% had distal embolization. Risks for major AE were COPD (OR 2.37; p=0.004), BUN>21 (OR 1.68; p=0.043), hypoalbuminemia (OR 3.00; p=0.002), and operative time >77mins (OR 1.92; p=0.013). Pre-procedural aspirin lowered odds of experiencing major AE (OR 0.43; p=0.035). Risk factors of 30-day readmissions were contralateral severe (OR 2.73; p=0.002) or complete (OR 3.07; p=0.001) stenosis, COPD (OR 2.01; p=0.003) and congestive heart failure (OR 2.85; p=0.004). In conclusion, almost half of CAS procedures were performed in asymptomatic patients. Periprocedural complications were higher than those reported in randomized trials. Physicians should use the findings for risk stratification.

MicroRNA-21 Modulates White Adipose Tissue Browning and Altered Thermogenesis in a Mouse Model of Polycystic Ovary Syndrome

Background and Aim: Polycystic ovary syndrome (PCOS) is associated with obesity, and white adipose tissue (WAT) and brown adipose tissue (BAT) dysregulation. However, the molecular mechanisms that mediate WAT and BAT derangements in PCOS are poorly understood. Subcutaneous (SC) WAT (SC-WAT) can transition to a beige/brite adipose tissue phenotype (browning) under altered thermogenic conditions. MicroRNAs play critical functions in brown adipocyte differentiation and maintenance. We aim to study the role of microRNA-21 (miR-21) in androgen-mediated browning and beiging derangements in both SC-WAT and BAT. Methods: Three week-old miR-21 knockout (miR21KO) or wild type (WT) female mice were treated with dihydrotestosterone (DHT, 8 mg/silastic tube) or vehicle for 90 days (n=12/grp). Body composition was measured by EchoMRI. Energy expenditure (EE), oxygen consumption (VO2), and carbon dioxide production (VCO2) were measured by indirect calorimetry. Glucose homeostasis was measured by oral glucose tolerance test (OGTT). HOMA-IR index was calculated from fasting serum glucose and insulin levels. Gene expression for browning (UCP1, Cox7a1, Elov3, Dio2 and Cidea) and beiging (Hspb7 and Txb1) markers was quantified by RT-qPCR in SC-WAT and BAT. Results: DHT increased body weight (25.07 ± 0.52 vs 21.79 ± 0.47 g, p<0.05) and fat mass (4.60 ± 0.46 vs 1.98 ± 0.12 g, p<0.05), impaired OGTT (186.10 ± 5.99 vs 250.70 ± 14.76 mg^.min/dL, p<0.05), and did not significantly change EE, VO2 or VCO2 in WT mice. All browning markers were downregulated by DHT in SC-WAT; however, only iodothyronine deiodinase 2 (Dio2) downregulation reached significance in both SC-WAT and BAT (by 53 and 40%, respectively) compared with the vehicle-treated mice. Beiging markers were significantly upregulated in SC-WAT and did not change in BAT. DHT-treated miR21KO mice showed attenuated DHT-mediated increase in body weight (23.84 ± 0.99 vs 25.07 ± 0.52 g, p<0.05) compared with WT mice. MiR-21 ablation did not modify DHT-mediated increase in fat mass or OGTT but worsened insulin resistance as calculated by the HOMA-IR index. Additionally, DHT-treated miR21KO mice showed a trend to reduced EE, VO2 and VCO2 values compared with DHT-treated WT. Gene expression analysis showed an exacerbation in DHT-mediated reduction in browning markers expression in the SC-WAT. Additionally, the induction in the adaptive beiging response was abolished in SC-WAT. Conclusion and Significance: These findings suggest that adipose tissue miR-21 may have a protective role in PCOS and ameliorate the DHT-mediated decrease in energy expenditure. Adipose tissue-specific modulation of miR-21 levels could be a novel therapeutic approach for the treatment of PCOS-associated metabolic derangements. (Supported by NIH grants NIGMS P20GM121334 to LLYC and DGR, NIDDK R21DK113500 to DGR, NIGMS P20GM104357 and NHLBI P01HL51971).

Genotypic correlation between post discharge Clostridiodes difficle infection (CDI) and previous unit-based contacts

BACKGROUND

Cases of Clostridiodes difficile infection (CDI) diagnosed after hospital discharge account for a substantial proportion of new infections. It is unclear whether post-discharge infections originate from hospital-based transmission.

METHODS

This was a Retrospective cohort study at a tertiary-care cancer center (non-outbreak setting). For all laboratory-identified cases of CDI in 2015-2016, patients with post-discharge (PD) CDI within eight weeks of their hospital stay were included in the study. Isolates from PD-CDI cases and their CDI-positive unit-based contacts were first genotyped by multilocus sequence typing (MLST). Common strains were further examined by core genome sequencing (CGS) to evaluate transmission links.

RESULTS

Of 173 cases examined by MLST, 50% of PD cases matched previous unit contacts. Next, 34 isolates, including 16 PD cases and their 18-unit contacts were examined by CGS. None were ≤3 single-nucleotide variants apart. Seventy percent of PD cases had in-hospital antibiotic exposure before CDI onset in the community.

CONCLUSION

Our study results suggest that symptomatic CDI cases are not a substantial source of transmission to PD cases. Frequent antibiotic exposure in post-discharge CDI cases is an important target for surveillance and stewardship efforts.

18F-sodium fluoride positron emission tomography-computed tomography in acute aortic syndrome

Background

Acute aortic syndrome is characterised by diseases that disrupt the intima and weaken the aorta. This damaged aorta is prone to aneurysmal dilation and ultimately rupture – a catastrophic event. 18F-sodium fluoride positron emission tomography and computed tomography (PET-CT) is a promising multimodality imaging technique that informs on the pathological state of the aorta. In abdominal aortic aneurysms (a chronic aortic disease), 18F-sodium fluoride PET uptake is associated with aortic expansion and requirement for aortic repair.

Purpose

The aim of this study was to describe aortic 18F-sodium fluoride uptake in patients with acute aortic syndrome for the first time.

Methods

Patients with intramural haematomas, aortic dissections or penetrating aortic ulcers, along with healthy control subjects, underwent contrast-enhanced 18F-sodium fluoride PET-CT. 18F-Sodium fluoride uptake was assessed using standardised uptake values and corrected for background blood pool activity to obtain tissue-to-background ratios (TBR).

Results

Forty-six patients and twenty healthy control subjects were matched for age, gender, body mass index, ischaemic heart disease and diabetes mellitus. Participants with acute aortic syndrome had widespread aortic 18F-sodium fluoride uptake. Radiotracer binding in patients with acute aortic syndrome was substantially greater than healthy subjects (TBR 2.00±0.45 vs 1.36±0.39, p&lt;0.001). Subgroup analysis in patients with untreated type B acute aortic dissection revealed peak radiotracer binding at the site of intimal disruption compared to the proximal reference aorta (TBR [inter-quartile range] 1.61 [1.38–1.88] vs 1.18 [1.08–1.39] respectively; p&lt;0.001).

Radiotracer uptake was highest in patients with penetrating aortic ulcers, followed by aortic dissection and intramural haematomas (TBR (±SD) 2.19±0.55 vs 1.99±0.43 vs 1.71±0.27 respectively; p=0.046). No difference in radiotracer uptake was observed between patients with sub-acute and chronic disease (TBR (±SD) 1.94±0.37 vs 2.04±0.51, p=0.497). 18F-sodium fluoride uptake was similar between Stanford Type A and Type B dissections (TBR (±SD) 1.98±0.49, 2.00±0.44, p=0.851). 18F-Sodium fluoride binding was independent of maximum aortic diameter (R2 = 0.036, p=0.21).

Conclusion

Our preliminary findings suggest that aortic 18F-sodium fluoride uptake is increased in patients with acute aortic syndrome, especially around the site of intimal disruption or penetrating aortic ulcers. This technique appears to identify disease activity that may have clinical applications for assessing prognosis and guiding therapeutic interventions.

18F-NaF PET/CT in Acute Aortic Syndrome

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Catheter ablation for atrial fibrillation in patients with reduced systolic function: a national perspective

Background

Randomized trials have shown improvement in hard clinical end points when catheter ablation (CA) was employed as a management strategy for certain atrial fibrillation (AF) patients with heart failure and reduced ejection fraction (HFrEF). We sought to determine real world data on mortality and complications after utilization of CA in such patients.

Methods and results

Data were derived from National Inpatient Sample from January 2008 to August 2015. Patients were identified using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes. Baseline characteristics and outcomes were compared among AF and HFrEF patients undergoing CA or not. Propensity matching was done to mitigate selection bias and balance confounding variables. Various CA related complications were assessed. Logistic regression was done to determine predictors of mortality in our study cohort. A total of 2,569,919 patients were enrolled and out of these approximately 7773 patients underwent CA. Mortality was significantly better in CA group in both unmatched (1.2% vs. 4.9%, p&lt;0.01) and propensity matched cohorts (1.2% vs. 3.6%, p&lt;0.01). Overall complication rate was 10.2% in CA cohort and were primarily cardiac and neurological in origin. In regression analysis, CA remains a strong predictor of reduced mortality (OR 0.301, 95% CI 0.184–0.494).

Conclusion

CA is associated with improved mortality in admitted AF patients with concomitant HFrEF. Overall complication rate after CA was modest at 10.2%.

Funding Acknowledgement

Type of funding source: None

Effect of GLP-1 Receptor Agonists in the Cardiometabolic Complications in a Rat Model of Postmenopausal PCOS

Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism and ovulatory dysfunction. Women with PCOS have an elevated prevalence of cardiometabolic risk factors that worsen after menopause. Liraglutide (Lira), a glucagon-like peptide-1 receptor agonist, has shown beneficial metabolic effects in small clinic trials in reproductive-age women with PCOS. We have shown that chronic hyperandrogenemia in an experimental model of postmenopausal PCOS is associated with an adverse cardiometabolic profile and upregulation of the intrarenal renin-angiotensin system (RAS). We analyzed the effect of Lira in the cardiometabolic profile, intrarenal RAS, and blood pressure (BP) in postmenopausal PCOS. Four-week-old female Sprague Dawley rats were treated with DHT or placebo for 17 months. Lira administration during the last 3 weeks caused a bigger reduction in food intake, body weight, fat mass, and homeostasis model assessment of insulin resistance index in PCOS than in control rats. Moreover, Lira improved dyslipidemia and elevated leptin levels in PCOS. In contrast, Lira decreased intrarenal expression of RAS components only in the control group. Lira transiently increased heart rate and decreased BP in control rats. However, Lira did not modify BP but increased heart rate in PCOS. The angiotensin-converting-enzyme inhibitor enalapril abolished the BP differences between PCOS and control rats. However, Lira coadministration with enalapril further reduced BP only in control rats. In summary, Lira has beneficial effects for several cardiometabolic risk factors in postmenopausal PCOS. However, hyperandrogenemia blunted the BP-lowering effect of Lira in postmenopausal PCOS. Androgen-induced activation of intrarenal RAS may play a major role mediating increases in BP in postmenopausal PCOS.

YAP, but Not RSPO-LGR4/5, Signaling in Biliary Epithelial Cells Promotes a Ductular Reaction in Response to Liver Injury

Biliary epithelial cells (BECs) form bile ducts in the liver and are facultative liver stem cells that establish a ductular reaction (DR) to support liver regeneration following injury. Liver damage induces periportal LGR5+ putative liver stem cells that can form BEC-like organoids, suggesting that RSPO-LGR4/5-mediated WNT/β-catenin activity is important for a DR. We addressed the roles of this and other signaling pathways in a DR by performing a focused CRISPR-based loss-of-function screen in BEC-like organoids, followed by in vivo validation and single-cell RNA sequencing. We found that BECs lack and do not require LGR4/5-mediated WNT/β-catenin signaling during a DR, whereas YAP and mTORC1 signaling are required for this process. Upregulation of AXIN2 and LGR5 is required in hepatocytes to enable their regenerative capacity in response to injury. Together, these data highlight heterogeneity within the BEC pool, delineate signaling pathways involved in a DR, and clarify the identity and roles of injury-induced periportal LGR5+ cells.

Glass confers rhabdomeric photoreceptor identity in Drosophila, but not across all metazoans

Across metazoans, visual systems employ different types of photoreceptor neurons (PRs) to detect light. These include rhabdomeric PRs, which exist in distantly related phyla and possess an evolutionarily conserved phototransduction cascade. While the development of rhabdomeric PRs has been thoroughly studied in the fruit fly Drosophila melanogaster, we still know very little about how they form in other species. To investigate this question, we tested whether the transcription factor Glass, which is crucial for instructing rhabdomeric PR formation in Drosophila, may play a similar role in other metazoans. Glass homologues exist throughout the animal kingdom, indicating that this protein evolved prior to the metazoan radiation. Interestingly, our work indicates that glass is not expressed in rhabdomeric photoreceptors in the planarian Schmidtea mediterranea nor in the annelid Platynereis dumerilii. Combined with a comparative analysis of the Glass DNA-binding domain, our data suggest that the fate of rhabdomeric PRs is controlled by Glass-dependent and Glass-independent mechanisms in different animal clades.

Breakup of finite-size liquid filaments: Transition from no-breakup to breakup including substrate effects⋆

This work studies the breakup of finite-size liquid filaments, when also including substrate effects, using direct numerical simulations. The study focuses on the effects of three parameters: Ohnesorge number, the ratio of the viscous forces to inertial and surface tension forces, the liquid filament aspect ratio, and where there is a substrate, a measure of the fluid slip on the substrate, i.e. slip length. Through these parameters, it is determined whether a liquid filament breaks up during the evolution toward its final equilibrium state. Three scenarios are identified: a collapse into a single droplet, the breakup into one or multiple droplets, and recoalescence into a single droplet after the breakup (or even possibly another breakup after recoalescence). The results are compared with the ones available in the literature for free-standing liquid filaments. The findings show that the presence of the substrate promotes the breakup of the filament. The effect of the degree of slip on the breakup is also discussed. The parameter domain regions are comprehensively explored when including the slip effects. An experimental case is also carried out to illustrate the collapse and breakup of a finite-size silicon oil filament supported on a substrate, showcasing a critical length of the breakup in a physical configuration. Finally, direct numerical simulations reveal striking new details into the breakup pattern for low Ohnesorge numbers, where the dynamics are fast and the experimental imaging is not available; our results therefore significantly extend the range of Ohnesorge number over which filament breakup has been considered.

MicroRNA-21 ablation exacerbates aldosterone-mediated cardiac injury, remodeling, and dysfunction

Primary aldosteronism is characterized by excess aldosterone secretion by the adrenal gland independent of the renin-angiotensin system and accounts for ~10% of hypertensive patients. Excess aldosterone causes cardiac hypertrophy, fibrosis, inflammation, and hypertension. The molecular mechanisms that trigger the onset and progression of aldosterone-mediated cardiac injury remain incompletely understood. MicroRNAs (miRNAs) are endogenous, small, noncoding RNAs that have been implicated in multiple cardiac pathologies; however, their regulation and role in aldosterone-mediated cardiac injury and dysfunction remains mostly unknown. We previously reported that microRNA-21 (miR-21) is the most upregulated miRNA by excess aldosterone in the left ventricle in a rat experimental model of primary aldosteronism. To elucidate the role of miR-21 in aldosterone-mediated cardiac injury and dysfunction, miR-21 knockout mice and their wild-type littermates were treated with aldosterone infusion and salt in the drinking water for 2 or 8 wk. miR-21 genetic ablation exacerbated aldosterone/salt-mediated cardiac hypertrophy and cardiomyocyte cross-sectional area. Furthermore, miR-21 genetic ablation increased the cardiac expression of fibrosis and inflammation markers and fetal gene program. miR-21 genetic ablation increased aldosterone/salt-mediated cardiac dysfunction but did not affect aldosterone/salt-mediated hypertension. miR-21 target gene Sprouty 2 may be implicated in the cardiac effects of miR-21 genetic ablation. Our study shows that miR-21 genetic ablation exacerbates aldosterone/salt-mediated cardiac hypertrophy, injury, and dysfunction blood pressure independently. These results suggest that miR-21 plays a protective role in the cardiac pathology triggered by excess aldosterone. Furthermore, miR-21 supplementation may be a novel therapeutic approach to abolish or mitigate excess aldosterone-mediated cardiovascular deleterious effects in primary aldosteronism.

Long-Lasting Androgen-Induced Cardiometabolic Effects in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS), the most common endocrine disorder in women of reproductive age, is characterized by androgen excess and ovarian dysfunction and presents with increased cardiometabolic risk factors such as obesity, insulin resistance, and elevated blood pressure (BP). We previously reported that administration of dihydrotestosterone (DHT) to female rats elicits cardiometabolic derangements similar to those found in women with PCOS. In this study, we tested the hypothesis that the DHT-mediated cardiometabolic derangements observed in PCOS are long lasting despite DHT withdrawal. Four-week-old female Sprague Dawley rats were treated with DHT (7.5 mg/90 days) or placebo for 6 months. DHT was discontinued (ex-DHT), and rats were followed for 6 additional months. After 6 months of DHT withdrawal, food intake, body weight, fat and lean mass, fasting plasma insulin, leptin, and adiponectin were elevated in ex-DHT rats. BP remained significantly elevated, and enalapril, an angiotensin-converting enzyme (ACE) inhibitor, normalized BP in ex-DHT rats. Expression of components of the intrarenal renin-angiotensin system was increased in ex-DHT rats. The cardiometabolic features found in ex-DHT rats were associated with lower plasma androgen levels but increased expression of renal and adipose tissue androgen receptors. In summary, androgen-induced cardiometabolic effects persisted after DHT withdrawal in a PCOS experimental model. Activation of intrarenal renin-angiotensin system plays a major role in the androgen-mediated increase in BP in ex-DHT. Upregulation of the renal and adipose tissue androgen receptor may explain the long-lasting effects of androgens. In clinical scenarios characterized by hyperandrogenemia in women, prompt normalization of androgen levels may be necessary to prevent their long-lasting cardiometabolic effects.

Altered neuro-inflammatory gene expression in hippocampus in major depressive disorder

Major Depressive Disorder (MDD) is a common psychiatric disorder for which available medications are often not effective. The high prevalence of MDD and modest response to existing therapies compels efforts to better understand and treat the disorder. Decreased hippocampal volume with increasing duration of depression suggests altered gene expression or even a decrease in neurogenesis. Tissue punches from the dentate gyrus were collected postmortem from 23 subjects with MDD and 23 psychiatrically-normal control subjects. Total RNA was isolated and whole transcriptome paired-end RNA-sequencing was performed using an Illumina NextSeq 500. For each sample, raw RNA-seq reads were aligned to the Ensembl GRCh38 human reference genome. Analysis revealed 30 genes differentially expressed in MDD compared to controls (FDR<0.05). Down-regulated genes included several with inflammatory function (ISG15, IFI44L, IFI6, NR4A1/Nur-77) and GABBR1 while up-regulated genes included several with cytokine function (CCL2/MCP-1), inhibitors of angiogenesis (ADM, ADAMTS9), and the KANSL1 gene, a histone acetyltransferase. Similar analyses of specific subsets of MDD subjects (suicide vs. non-suicide, single vs. multiple episodes) yielded similar, though not identical, results. Enrichment analysis identified an over-representation of inflammatory and neurogenesis-related (ERK/MAPK) signaling pathways significantly altered in the hippocampal dentate gyrus in MDD. Together, these data implicate neuro-inflammation as playing a crucial role in MDD. These findings support continued efforts to identify adjunctive approaches towards the treatment of MDD with drugs including anti-inflammatory and neuroprotective properties.

MicroRNA-21: Expression in oligodendrocytes and correlation with low myelin mRNAs in depression and alcoholism

MiR-21 is a microRNA implicated in cancer, development, and cardiovascular diseases and expressed in the central nervous system (CNS), especially after injury. However, the cellular expression of miR-21 in the adult CNS has not been clearly established either in mice or human subjects, while its alteration in psychiatric disorders is unknown. MiR-21 expression was characterized in reporter mice expressing β-galactosidase (LacZ) under the endogenous miR-21 promoter (miR-21/LacZ). Brain co-localization of miR-21/LacZ with specific neural markers was examined by double immunofluorescence in reporter mice, while extent of immunostaining for myelin basic protein and PDGFRα was determined in miR-21 knockout and wild-type mice. Levels of miR-21, and mRNAs of selected miR-21 targets, miR-21 regulator STAT3 and myelin-related proteins were measured by qRT-PCR in the white matter (WM) adjacent to the left postmortem orbitofrontal cortex (OFC) of human subjects with major depressive disorder (MDD), alcoholism, comorbid MDD plus alcoholism (MDA) and non-psychiatric control subjects. MiR-21/LacZ was highly expressed in cell bodies of WM and myelinated portions of gray matter (GM). Labeled cell bodies were identified as oligodendrocytes, while miR-21/LacZ was barely detectable in other cell types. MiR-21, as well as the mRNAs of several myelin-related proteins, were reduced in the WM of subjects with MDD and alcoholism. MiR-21 positively correlated with mRNA of myelin-related proteins and astrocytic GFAP. High expression of miR-21 in adult oligodendrocytes and the correlation of miR-21 decrease with mRNA of some myelin proteins, regulator STAT3, and oligodendrocyte-related transcription factors suggest an involvement of miR-21 in WM alterations in depression and alcoholism.

Role and Regulation of MicroRNAs in Aldosterone-Mediated Cardiac Injury and Dysfunction in Male Rats

Primary aldosteronism is characterized by excess aldosterone (ALDO) secretion independent of the renin-angiotensin system and accounts for approximately 10% of hypertension cases. Excess ALDO that is inappropriate for salt intake status causes cardiac hypertrophy, inflammation, fibrosis, and hypertension. The molecular mechanisms that trigger the onset and progression of ALDO-mediated cardiac injury are poorly understood. MicroRNAs (miRNAs) are endogenous, small, noncoding RNAs that have been implicated in diverse cardiac abnormalities, yet very little is known about their regulation and role in ALDO-mediated cardiac injury. To elucidate the regulation of miRNAs in ALDO-mediated cardiac injury, we performed a time-series analysis of left ventricle (LV) miRNA expression. Uninephrectomized male Sprague-Dawley rats were treated with ALDO (0.75 µg/h) infusion and SALT (1.0% NaCl/0.3% KCl) in the drinking water for up to 8 weeks. ALDO/SALT time dependently modulated the expression of multiple miRNAs in the LV. miR-21 was the most upregulated miRNA after 2 weeks of treatment and remained elevated until the end of the study. To elucidate the role of miR-21 in ALDO/SALT-mediated cardiac injury, miR-21 was downregulated by using antagomirs in ALDO/SALT-treated rats. miR-21 downregulation exacerbated ALDO/SALT-mediated cardiac hypertrophy, expression of fibrosis marker genes, interstitial and perivascular fibrosis, OH-proline content, and cardiac dysfunction. These results suggest that ALDO/SALT-mediated cardiac miR-21 upregulation may be a compensatory mechanism that mitigates ALDO/SALT-mediated cardiac deleterious effects. We speculate that miR-21 supplementation would have beneficial effects in reverting or mitigating cardiac injury and dysfunction in patients with primary aldosteronism.

mTOR Regulates Endocytosis and Nutrient Transport in Proximal Tubular Cells

Renal proximal tubular cells constantly recycle nutrients to ensure minimal loss of vital substrates into the urine. Although most of the transport mechanisms have been discovered at the molecular level, little is known about the factors regulating these processes. Here, we show that mTORC1 and mTORC2 specifically and synergistically regulate PTC endocytosis and transport processes. Using a conditional mouse genetic approach to disable nonredundant subunits of mTORC1, mTORC2, or both, we showed that mice lacking mTORC1 or mTORC1/mTORC2 but not mTORC2 alone develop a Fanconi-like syndrome of glucosuria, phosphaturia, aminoaciduria, low molecular weight proteinuria, and albuminuria. Interestingly, proteomics and phosphoproteomics of freshly isolated kidney cortex identified either reduced expression or loss of phosphorylation at critical residues of different classes of specific transport proteins. Functionally, this resulted in reduced nutrient transport and a profound perturbation of the endocytic machinery, despite preserved absolute expression of the main scavenger receptors, MEGALIN and CUBILIN. Our findings highlight a novel mTOR-dependent regulatory network for nutrient transport in renal proximal tubular cells.

Abstract P4-10-09: Relapse-free survival of triple negative breast cancer long term survivors and characterization of late events in MD Anderson experience

Background:

Stage I-III TNBC patients have a high risk of disease relapse during the first 5 years after diagnosis. However, there is limited data on the risk of late relapse in TNBC survivors who are disease free at 5 years or more from diagnosis. We sought to characterize this risk in a cohort of TNBC long-term survivors from a large institutional database.

Methods:

The MD Anderson Breast Cancer Management System database was queried for TNBC survivors who were disease free 5 years or more from diagnosis. Demographic, tumor, and treatment data was extracted. Electronic medical records were searched to confirm pathology reports for invasive breast cancer diagnosis, triple negative receptor status, and hormone receptor percentage (%). The primary and secondary outcomes of interest were relapse free survival (RFS) and distant relapse free survival (DRFS). Patients were censored at time of developing a second primary breast cancer or at last follow-up time for those who were alive during the study. We used ACP-ASCO definition of ER and PR &lt;1% and HER2/neu negative (IHC 0-1 or ratio &lt;2 and average copy number &lt;4) but also included patients with low ER/PR(1-9%) and HER2 normal. Kaplan-Meier analysis was performed to compare RFS and DRFS for the overall population and categorized by ER/PR &lt;1%, and ER/PR 1-9%.

Results:

We identified 1038 patients who had a median follow-up of 8.0 years. Receptor % information was available on 69% of patients, with 78% of them meeting current TNBC definition. From the total cohort of 130, 12.5% suffered event(s) that occurred after 5 years from diagnosis, with 86.2% of them occurring within 5-10 years of diagnosis. The event rate was 16.4% among patients with ER/PR 1-9% versus 11.3% among patients with ER/PR &lt;1%. Table 1 shows RFS and DRFS by year from diagnosis for the entire cohort and categorized by % receptor. 18 patients developed second primary breast cancer as first event and were censored. Of total events recorded, 53(40.8%) were deaths and 77(59.2%) were recurrences, of which 51(66%) were distant and 26(34%) local, of whom 12(46.2%) subsequently developed distant metastases. Among patients who initially presented with distant recurrence, frequencies of initial sites of metastases are shown in Table 2.

Conclusions:

TNBC long term survivors are still at risk for relapse events after 5 years from diagnosis, and it is important to quantity this risk when counseling our patients. Frequency of late events was higher among patients with low hormone receptor positivity. Multivariate modeling of predictors of late recurrence is ongoing.

Table 1: RFS and DRFS by Year from Diagnosis All PatientsER/PR &lt;1%ER/PR 1-9%Year From DiagnosisRFSDRFSRFSDRFSRFSDRFS4-51.01.01.01.01.01.05-60.950.960.940.950.940.956-70.930.940.930.940.910.927-80.900.920.900.920.870.898-90.860.880.870.890.810.849-100.840.870.840.860.800.8310-120.810.840.810.830.800.8312-150.730.780.730.750.670.74

Table 2: Site of Initial Distant RecurrenceSiteN (%)Lung/Pleura28 (54.9)Bone19 (37.3)Distant Lymph Nodes19 (37.3)Liver11 (21.6)Brain/Spinal Cord8 (15.7)Colorectal/Pancreas/Kidney/Adrenal6 (11.7)Other2 (3.9)*Patients presenting with multiple sites of distant recurrence are counted in each category.

Citation Format: Reddy SM, Sinha A, Syed M, Barcenas C, Valero V. Relapse-free survival of triple negative breast cancer long term survivors and characterization of late events in MD Anderson experience. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-10-09.

Abstract 403: MicroRNA-21 Ablation Exacerbates Aldosterone-mediated Cardiac Inflammation, Fibrosis, Hypertrophy and Dysfunction

Excess aldosterone (ALDO) causes hypertension and cardiac hypertrophy, inflammation and fibrosis that lead to cardiac dysfunction. We reported that ALDO/SALT treatment increases left ventricle miR-21 expression after 2 weeks of treatment, and the elevation persists for up to 8 weeks. We aim to study the role of genetic ablation of miR-21 in ALDO/SALT-mediated cardiac inflammation, fibrosis, hypertrophy and function.

Eight-week old uninephrectomized male miR-21 knockout (miR21KO) or wild-type (WT) mice were assigned to 4 groups (N=12/grp): WT-Control, WT-ALDO/SALT, miR21KO-Control and miR21KO-ALDO/SALT. Animals were treated for 8 weeks. ALDO (0.15 μg/h) or vehicle (PEG 300) was administered by osmotic minipump. SALT (1.0% NaCl + 0.3% KCl) was administered in tap water. Cardiac function was determined by echocardiography. Tissues were weighed and standardized to body weight. mRNA levels were quantified by qPCR. Another set of animals (N=12/grp) was implanted with carotid artery catheters for conscious MAP determination.

ALDO/SALT-mediated cardiac dysfunction was exacerbated in miR21KO mice (EF: 38.0 ± 2.0 vs. 43.0 ± 4.1 %, p <0.05) compared with WT mice (EF: 50.0 ± 3.7 vs. 54.7 ± 3.1 %, NS). ALDO/SALT-mediated cardiac hypertrophy was exacerbated in miR21KO mice compared with WT mice (ALDO-SALT/control: 1.30 ± 0.04 vs . 1.18 ± 0.02, p <0.05).

Fibrosis marker connective tissue growth factor (Ctgf) mRNA expression remained elevated by ALDO/SALT only in miR21KO mice (7.22 ± 1.96 fold change vs . control, p <0.05). Similar results were observed with collagen I and fibronectin. Inflammation marker Serpine1 (PAI-1) mRNA expression was upregulated by ALDO/SALT only in miR21KO mice (3.11 ± 0.54 fold change vs . control, p <0.05).

Despite the exacerbation in cardiac dysfunction, hypertrophy, and fibrosis and inflammation markers expression in miR21KO mice, ALDO/SALT raised MAP to similar levels in both strains (WT: 139 ± 9 vs . 106 ± 2 mm Hg, p <0.05; miR21KO: 142 ± 8 vs . 114 ± 4, p < 0.05).

These results show that miR-21 ablation exacerbates ALDO/SALT-mediated cardiac inflammation, fibrosis, hypertrophy and dysfunction independently of blood pressure suggesting that therapies that increase cardiac levels of miR-21 may benefit patients with primary aldosteronism.