FOXO-mediated repression of Dicer1 regulates metabolism, stress resistance, and longevity in Drosophila.

The adipose tissue plays a crucial role in metabolism and physiology, affecting animal lifespan and susceptibility to disease. In this study, we present evidence that adipose Dicer1 (Dcr-1), a conserved type III endoribonuclease involved in miRNA processing, plays a crucial role in the regulation of metabolism, stress resistance, and longevity. Our results indicate that the expression of Dcr-1 in murine 3T3L1 adipocytes is responsive to changes in nutrient levels and is subject to tight regulation in the Drosophila fat body, analogous to human adipose and hepatic tissues, under various stress and physiological conditions such as starvation, oxidative stress, and aging. The specific depletion of Dcr-1 in the Drosophila fat body leads to changes in lipid metabolism, enhanced resistance to oxidative and nutritional stress, and is associated with a significant increase in lifespan. Moreover, we provide mechanistic evidence showing that the JNK-activated transcription factor FOXO binds to conserved DNA-binding sites in the dcr-1 promoter, directly repressing its expression in response to nutrient deprivation. Our findings emphasize the importance of FOXO in controlling nutrient responses in the fat body by suppressing Dcr-1 expression. This mechanism coupling nutrient status with miRNA biogenesis represents a novel and previously unappreciated function of the JNK-FOXO axis in physiological responses at the organismal level.

Genomic analysis unveils genome degradation events and gene flux in the emergence and persistence of S. Paratyphi A lineages.

Paratyphoid fever caused by S. Paratyphi A is endemic in parts of South Asia and Southeast Asia. The proportion of enteric fever cases caused by S. Paratyphi A has substantially increased, yet only limited data is available on the population structure and genetic diversity of this serovar. We examined the phylogenetic distribution and evolutionary trajectory of S. Paratyphi A isolates collected as part of the Indian enteric fever surveillance study "Surveillance of Enteric Fever in India (SEFI)." In the study period (2017-2020), S. Paratyphi A comprised 17.6% (441/2503) of total enteric fever cases in India, with the isolates highly susceptible to all the major antibiotics used for treatment except fluoroquinolones. Phylogenetic analysis clustered the global S. Paratyphi A collection into seven lineages (A-G), and the present study isolates were distributed in lineages A, C and F. Our analysis highlights that the genome degradation events and gene acquisitions or losses are key molecular events in the evolution of new S. Paratyphi A lineages/sub-lineages. A total of 10 hypothetically disrupted coding sequences (HDCS) or pseudogenes-forming mutations possibly associated with the emergence of lineages were identified. The pan-genome analysis identified the insertion of P2/PSP3 phage and acquisition of IncX1 plasmid during the selection in 2.3.2/2.3.3 and 1.2.2 genotypes, respectively. We have identified six characteristic missense mutations associated with lipopolysaccharide (LPS) biosynthesis genes of S. Paratyphi A, however, these mutations confer only a low structural impact and possibly have minimal impact on vaccine effectiveness. Since S. Paratyphi A is human-restricted, high levels of genetic drift are not expected unless these bacteria transmit to naive hosts. However, public-health investigation and monitoring by means of genomic surveillance would be constantly needed to avoid S. Paratyphi A serovar becoming a public health threat similar to the S. Typhi of today.

Smaug1 membrane-less organelles respond to AMPK and mTOR and affect mitochondrial function.

Smaug is a conserved translational regulator that binds numerous mRNAs, including nuclear transcripts that encode mitochondrial enzymes. Smaug orthologs form cytosolic membrane-less organelles (MLOs) in several organisms and cell types. We have performed single-molecule fluorescence in situ hybridization (FISH) assays that revealed that SDHB and UQCRC1 mRNAs associate with Smaug1 bodies in U2OS cells. Loss of function of Smaug1 and Smaug2 (also known as SAMD4A and SAMD4B, respectively) affected both mitochondrial respiration and morphology of the mitochondrial network. Phenotype rescue by Smaug1 transfection depends on the presence of its RNA-binding domain. Moreover, we identified specific Smaug1 domains involved in MLO formation, and found that impaired Smaug1 MLO condensation correlates with mitochondrial defects. Mitochondrial complex I inhibition upon exposure to rotenone, but not strong mitochondrial uncoupling upon exposure to CCCP, rapidly induced the dissolution of Smaug1 MLOs. Metformin and rapamycin elicited similar effects, which were blocked by pharmacological inhibition of AMP-activated protein kinase (AMPK). Finally, we found that Smaug1 MLO dissolution weakens the interaction with target mRNAs, thus enabling their release. We propose that mitochondrial respiration and the AMPK-mTOR balance controls the condensation and dissolution of Smaug1 MLOs, thus regulating nuclear mRNAs that encode key mitochondrial proteins. This article has an associated First Person interview with the first authors of the paper.

SARS-CoV-2 vaccination response in pediatric oncology patients.

BACKGROUND: There remains limited knowledge about the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in pediatric oncology patients, which is essential to provide counseling and risk adaptation in this vulnerable population. The goal of this study was to understand immunogenicity after vaccination in pediatric oncology patients, and determine if certain clinical factors impacted response. METHODS: Patients 0-25 years of age with a diagnosis of cancer and actively receiving therapy were enrolled on study. We excluded patients who were completely vaccinated prior to their cancer diagnosis. Blood samples were collected pre-vaccination, as well as 2, 4-6, and 8-12 weeks after vaccination. Healthy children who were fully vaccinated enrolled as controls. Clinical data and complete blood counts around time of vaccination were collected. To study B- and T-cell immunity, we measured neutralizing antibodies by enzyme-linked immunoassay and interferon gamma secretion by enzyme-linked immunospot, respectively. RESULTS: Twenty-six patients enrolled on study, for which 11 were evaluable oncology patients and seven were healthy controls. Adequate B-cell response was seen in 36.4% of patients, and adequate T-cell response in 77.8% of patients. Numbers were too small to detect differences based on malignancy type. There was no differences in immunity based on absolute lymphocyte count (ALC) or intensity of therapy. CONCLUSION: Pediatric oncology patients have a suboptimal immune response to SARS-CoV-2 vaccination. Booster doses will be imperative to provide optimal protection against COVID-19; however, blood counts may not be a useful guide to optimize the time of administration.

Recurring episodes of bundle branch reentry ventricular tachycardia due to aortitis preceded by SARS-CoV-2 infection: a case report.

BACKGROUND: SARS-CoV-2 may trigger both vasculitis and arrhythmias as part of a multisystem inflammatory syndrome described in children as well as in adults following COVID-19 infection with only minor respiratory symptoms. The syndrome denotes a severe dysfunction of one or more extra-pulmonary organ systems, with symptom onset approximately 2-5 weeks after the COVID-19 infection. In the present case, a seemingly intractable ventricular tachycardia preceded by SARS-CoV2 infection was only managed following the diagnosis and management of aortitis. CASE PRESENTATION: A 69-year-old woman was hospitalized due to syncope, following a mild COVID-19 infection. She presented with paroxysmal atrial fibrillation and intermittent ventricular tachycardia interpreted as a septum-triggered bundle branch reentry ventricular tachycardia, unaffected by amiodaron, lidocaine and adenosine. A CT-scan revealed inflammation of the aortic arch, extending into the aortic root. In the following days, the tachycardia progressed to ventricular storm with intermittent third-degree AV block. A temporary pacemaker was implanted, and radiofrequency ablation was performed to both sides of the ventricular septum after which the ventricular tachycardia was non-inducible. Following supplemental prednisolone treatment, cardiac symptoms and arrythmia subsided, but recurred after tapering. Long-term prednisolone treatment was therefore initiated with no relapse in the following 14 months. CONCLUSION: We present a rare case of aortitis complicated with life-threatening ventricular tachycardia presided by Covid-19 infection without major respiratory symptoms. Given a known normal AV conduction prior to the COVID-19 infection, it seems likely that the ensuing aortitis in turn affected the septal myocardium, enabling the reentry tachycardia. Generally, bundle branch reentry tachycardia is best treated with radiofrequency ablation, but if it is due to aortitis with myocardial affection, long-term anti-inflammatory treatment is mandatory to prevent relapse and assure arrhythmia control. Our case highlights importance to recognize the existence of the multisystem inflammatory syndrome in adults (MIS-A) following COVID-19 infection in patients with alarming cardiovascular symptoms. The case shows that the early use of an CT-scan was crucial for both proper diagnosis and treatment option.

Driving following defibrillator implantation: a nationwide register-linked survey study.

AIMS: Patients are restricted from driving following implantable cardioverter defibrillator (ICD) implantation or shock. We sought to investigate how many patients are aware of, and adhere to, the driving restrictions, and what proportion experience an ICD shock or other cardiac symptoms while driving. METHODS AND RESULTS: We performed a nationwide survey of all living Danish residents 18 years or older who received a first-time ICD between 2013 and 2016 (n = 3913) and linked their responses with nationwide registers. Of 2741 respondents (47% primary prevention, 83% male, median age 67 years), 2513 (92%) held a valid driver's license at ICD implantation, 175 (7%) of whom had a license for professional driving. Many drivers were unaware of driving restrictions: primary prevention 58%; secondary prevention 36%; post-appropriate shock 28%; professional drivers 55%. Almost all (94%) resumed non-professional driving after ICD implantation, more than one-third during the restricted period; 35% resumed professional driving. During a median follow-up of 2.3 years, 5 (0.2%) reported receiving an ICD shock while driving, one of which resulted in a traffic accident. The estimated risk of harm was 0.0002% per person-year. CONCLUSION: In this nationwide study, many ICD patients were unaware of driving restrictions, and more than one third resumed driving during a driving restriction period. However, the rate of reported ICD shocks while driving was very low.

Ileal Perforation and Enteric Fever: Implications for Burden of Disease Estimation.

BACKGROUND: Ileal perforation occurs in about 1% of enteric fevers as a complication, with a case fatality risk (CFR) of 20%-30% in the early 1990s that decreased to 15.4% in 2011 in South East Asia. We report nontraumatic ileal perforations and its associated CFR from a 2-year prospective enteric fever surveillance across India. METHODS: The Surveillance for Enteric Fever in India (SEFI) project established a multitiered surveillance system for enteric fever between December 2017 and March 2020. Nontraumatic ileal perforations were surveilled at 8 tertiary care and 6 secondary care hospitals and classified according to etiology. RESULTS: Of the 158 nontraumatic ileal perforation cases identified,126 were consented and enrolled. Enteric fever (34.7%), tuberculosis (19.0%), malignancy (5.8%), and perforation of Meckel diverticulum (4.9%) were the common etiology. In those with enteric fever ileal perforation, the CFR was 7.1%. CONCLUSIONS: Enteric fever remains the most common cause of nontraumatic ileal perforation in India, followed by tuberculosis. Better modalities of establishing etiology are required to classify the illness, and frame management guidelines and preventive measures. CFR data are critical for comprehensive disease burden estimation and policymaking.

Cost of Illness Due to Severe Enteric Fever in India.

BACKGROUND: Lack of robust data on economic burden due to enteric fever in India has made decision making on typhoid vaccination a challenge. Surveillance for Enteric Fever network was established to address gaps in typhoid disease and economic burden. METHODS: Patients hospitalized with blood culture-confirmed enteric fever and nontraumatic ileal perforation were identified at 14 hospitals. These sites represent urban referral hospitals (tier 3) and smaller hospitals in urban slums, remote rural, and tribal settings (tier 2). Cost of illness and productivity loss data from onset to 28 days after discharge from hospital were collected using a structured questionnaire. The direct and indirect costs of an illness episode were analyzed by type of setting. RESULTS: In total, 274 patients from tier 2 surveillance, 891 patients from tier 3 surveillance, and 110 ileal perforation patients provided the cost of illness data. The mean direct cost of severe enteric fever was US$119.1 (95% confidence interval [CI], US$85.8-152.4) in tier 2 and US$405.7 (95% CI, 366.9-444.4) in tier 3; 16.9% of patients in tier 3 experienced catastrophic expenditure. CONCLUSIONS: The cost of treating enteric fever is considerable and likely to increase with emerging antimicrobial resistance. Equitable preventive strategies are urgently needed.

Evaluation of Antimicrobial Susceptibility Profile in Salmonella Typhi and Salmonella Paratyphi A: Presenting the Current Scenario in India and Strategy for Future Management.

BACKGROUND: Systematic studies to estimate the disease burden of typhoid and paratyphoid in India are limited. Therefore, a multicenter study on the Surveillance of Enteric Fever in India was carried out to estimate the incidence, clinical presentation, and antimicrobial resistance (AMR) trend. The data presented here represent the national burden of AMR in Salmonella Typhi and Salmonella Paratyphi A. METHODS: Antimicrobial susceptibility testing was performed for S. Typhi and S. Paratyphi A (n = 2373) isolates collected prospectively during a 2-year period from November 2017 to January 2020. RESULTS: Of 2373 Salmonella isolates, 2032 (85.6%) were identified as S. Typhi and 341 (14.4%) were S. Paratyphi A. Approximately 2% of S. Typhi were multidrug-resistant (MDR), whereas all 341 (100%) of S. Paratyphi A isolates were sensitive to the first-line antimicrobials. Among 98% of ciprofloxacin nonsusceptible isolates, resistance (minimum inhibitory concentration [MIC] >0.5 µg/mL) was higher in S. Typhi (37%) compared with S. Paratyphi A (20%). Azithromycin susceptibility was 99.9% and 100% with a mean MIC of 4.98 µg/mL for S. Typhi and 7.39 µg/mL for S. Paratyphi A respectively. Ceftriaxone was the only agent that retained 100% susceptibility. Moreover, beta-lactam/beta-lactamase inhibitors showed potent in vitro activity against the study isolates. CONCLUSIONS: Data obtained from this systematic surveillance study confirms the declining trend of MDR Salmonella isolates from India. The higher prevalence of ciprofloxacin nonsusceptibility enforces to limit its use and adhere to the judicious usage of azithromycin and ceftriaxone for enteric fever management.

Optimizing type 1 diabetes after multiple daily injections and capillary blood monitoring: Pump or sensor first? A meta-analysis using pooled differences in outcome measures.

AIMS: Most people living with type 1 diabetes self-manage using multiple daily injection (MDI) insulin regimens and self-monitoring of blood glucose (SMBG). Continuous subcutaneous insulin infusion (CSII) and continuous glucose monitoring (CGM) are adjuncts to education and support self-management optimization. The aim of this systematic review and meta-analysis was to assess which first-line technology is most effective. METHODS: Electronic databases (MEDLINE, EMBASE and WEB OF SCIENCE) were systematically searched from 1999 to September 2020. Randomized controlled trials comparing either CSII with MDI or CGM with SMBG in adults with type 1 diabetes were included. Data were extracted in duplicate by two reviewers, and were analysed to assess individual and overall treatment effect measures (PROSPERO registration: CRD42020149915). RESULTS: Glycated haemoglobin was significantly reduced for CGM when compared with SMBG [Cohen's d - 0.62 (95% CI -0.79 to -0.45)] and for CSII when compared with MDI [Cohen's d - 0.44 (95% CI -0.67 to -0.22)]. Rates of severe hypoglycaemia were significantly reduced with CGM compared with SMBG, but did not change for CSII when compared with MDI. Episodes of diabetic ketoacidosis were more likely to occur with CSII than MDI. Both CSII and CGM reduced glucose standard deviation, compared with MDI and SMBG respectively. CONCLUSIONS: Both CGM and CSII remain impactful interventions compared with SMBG and MDI but in adults with type 1 diabetes and in the contexts in which they have been studied, CGM might have a greater positive impact on glycaemic variability and severe hypoglycaemia than CSII, when added to MDI and SMBG. A head-to-head study, including patient reported outcomes, is required to explore these findings further.

Assessing the feasibility and acceptability of a cluster-randomized study of cognitive behavioral therapy for chronic insomnia in a primary care setting.

BACKGROUND: Cognitive behavioral therapy for chronic insomnia (CBT-i) is the treatment of choice for this condition but is underutilized in patients who attend primary care. The purpose of the present feasibility-pilot study was to assess the feasibility and acceptability of a cluster-randomized study of CBT-i in a primary care setting. METHODS: This study, performed at two primary health care centers in Majorca, Spain, was a mixed methods feasibility-pilot study of a parallel cluster-randomized design comparing CBT-i and usual care (UC). Patients were included if they were 18 to 65 years-old; had diagnoses of chronic insomnia according to the Insomnia Severity Index (ISI ≥ 8); had insomnia for more than 3 months. Twenty-five GPs and nurses and 32 patients were randomly allocated to two groups. The main outcome of the intervention was improvement of dimensions of sleep quality, measured using the Spanish version of the Pittsburgh Sleep Quality Index, at baseline and at 3 months after the intervention. Other primary outcomes of the study were the feasibility and applicability of the intervention, collected through nominal groups. A thematic analysis was performed to classify primary care provider (PCP) proposals. Additionally, we assessed the recruitment process, compliance with the intervention sessions, and patient retention. RESULTS: We adapted the CBT-i approach of Morin to a primary care context. After intervention training, PCPs expressed the need for more extensive training in the different aspects of the therapy and the discussion of more cases. PCPs considered the intervention as adequate but wanted fewer but longer sessions as well as to discard the cognitive restructuring component. PCPs considered it crucial to prepare each session in advance and to establish a specific agenda for the CBT-i. Regular reminders given to PCPs and patients were suggested to improve study participation. Compared to the UC group, higher proportions of patients in the intervention group had short sleep latency, slept for longer than 5 h, and had fewer sleep disruptions. CONCLUSIONS: This feasibility-pilot study identified several key issues that must be addressed before performing a CBT-i intervention in future clinical trial in a primary care setting. TRIAL REGISTRATION: NCT04565223 . (Clinical trials.gov) Registered 1 September 2020-Retrospectively registered.

Predictors of Distant Metastases in Triple-Negative Breast Cancer Without Pathologic Complete Response After Neoadjuvant Chemotherapy.

BACKGROUND: Pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) for triple-negative breast cancer (TNBC) predicts decreased distant metastasis. However, most patients do not experience pCR, and other risk factors for distant metastasis after NAC are poorly characterized. This study investigated factors predictive of distant metastasis in TNBC without pCR after NAC. METHODS: Women with TNBC treated with NAC, surgery, and radiation therapy in 2000 through 2013 were reviewed. Freedom from distant metastasis (FFDM) was compared between patients with and without pCR using the Kaplan-Meier method. In patients without pCR, univariate and multivariable Cox analyses were used to determine factors predictive of distant metastasis. RESULTS: We identified 153 patients with median follow-up of 4.0 years (range, 0.5-14.0 years). After NAC, 108 had residual disease (pCR, 29%). Five-year FFDM was 98% and 55% in patients with and without pCR, respectively (P<.001). Factors independently predicting FFDM in patients without pCR were pathologic nodal positivity (hazard ratio, 3.08; 95% CI, 1.54-6.14; P=.001) and lymphovascular space invasion (hazard ratio, 1.91; 95% CI, 1.07-3.43; P=.030). Patients with a greater number of factors had worse FFDM; 5-year FFDM was 76.5% for patients with no factors (n=38) versus 54.9% and 27.5% for patients with 1 (n=44) and 2 factors (n=26), respectively (P<.001). CONCLUSIONS: Lack of pCR after NAC resulted in worse overall survival and FFDM, despite trimodality therapy. In patients with residual disease after NAC, pathologic lymph node positivity and lymphovascular space invasion predicted worse FFDM.

Long-term follow-up of abandoned transvenous defibrillator leads: a nationwide cohort study.

AIMS: Commonly, a dysfunctional defibrillator lead is abandoned and a new lead is implanted. Long-term follow-up data on abandoned leads are sparse. We aimed to investigate the incidence and reasons for extraction of abandoned defibrillator leads in a nationwide cohort and to describe extraction procedure-related complications. METHODS AND RESULTS: All abandoned transvenous defibrillator leads were identified in the Danish Pacemaker and ICD Register from 1991 to 2019. The event-free survival of abandoned defibrillator leads was studied, and medical records of patients with interventions on abandoned defibrillator leads were audited for procedure-related data. We identified 740 abandoned defibrillator leads. Meantime from implantation to abandonment was 7.2 ± 3.8 years with mean patient age at abandonment of 66.5 ± 13.7 years. During a mean follow-up after abandonment of 4.4 ± 3.1 years, 65 (8.8%) abandoned defibrillator leads were extracted. Most frequent reason for extraction was infection (pocket and systemic) in 41 (63%) patients. Procedural outcome after lead extraction was clinical success in 63 (97%) patients. Minor complications occurred in 3 (5%) patients, and major complications in 1 (2%) patient. No patient died from complication to the procedure during 30-day follow-up after extraction. CONCLUSION: More than 90% of abandoned defibrillator leads do not need to be extracted during long-term follow-up. The most common indication for extraction is infection. Abandoned defibrillator leads can be extracted with high clinical success rate and low risk of major complications at high-volume centres.

Predictors of Locoregional Recurrence After Failure to Achieve Pathologic Complete Response to Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer.

BACKGROUND: This study evaluated factors predictive of locoregional recurrence (LRR) in women with triple-negative breast cancer (TNBC) treated with neoadjuvant chemotherapy who do not experience pathologic complete response (pCR). METHODS: This is a single-institution retrospective review of women with TNBC treated with neoadjuvant chemotherapy, surgery, and radiation therapy in 2000 through 2013. LRR was estimated between patients with and without pCR using the Kaplan-Meier method. Patient-, tumor-, and treatment-specific factors in patients without pCR were analyzed using the Cox proportional hazards method to evaluate factors predictive of LRR. Log-rank statistics were then used to compare LRR among these risk factors. RESULTS: A total of 153 patients with a median follow-up of 48.6 months were included. The 4-year overall survival and LRR were 70% and 15%, respectively, and the 4-year LRR in patients with pCR was 0% versus 22.0% in those without (P<.001). In patients without pCR, lymphovascular space invasion (LVSI; hazard ratio, 3.92; 95% CI, 1.64-9.38; P=.002) and extranodal extension (ENE; hazard ratio, 3.32; 95% CI, 1.35-8.15; P=.009) were significant predictors of LRR in multivariable analysis. In these patients, the 4-year LRR with LVSI was 39.8% versus 15.0% without (P<.001). Similarly, the 4-year LRR was 48.1% with ENE versus 16.1% without (P=.002). In patients without pCR, the presence of both LVSI and ENE were associated with an even further increased risk of LRR compared with patients with either LVSI or ENE alone and those with neither LVSI nor ENE in the residual tumor (P<.001). CONCLUSIONS: In patients without pCR, the presence of LVSI and ENE increases the risk of LRR in TNBC. The risk of LRR is compounded when both LVSI and ENE are present in the same patient. Future clinical trials are warranted to lower the risk of LRR in these high-risk patients.

Treatment response as predictor for brain metastasis in triple negative breast cancer: A score-based model.

BACKGROUND: Triple negative breast cancer (TNBC) has worse prognosis than other subtypes of breast cancer, and many patients develop brain metastasis (BM). We developed a simple predictive model to stratify the risk of BM in TNBC patients receiving neo-adjuvant chemotherapy (NAC), surgery, and radiation therapy (RT). METHODS: Patients with TNBC who received NAC, surgery, and RT were included. Cox proportional hazards method was used to evaluate factors associated with BM. Significant factors predictive for BM on multivariate analysis (MVA) were used to develop a risk score. Patients were divided into three risk groups: low, intermediate, and high. A receiver operating characteristic (ROC) curve was drawn to evaluate the value of the risk group in predicting BM. This predictive model was externally validated. RESULTS: A total of 160 patients were included. The median follow-up was 47.4 months. The median age at diagnosis was 49.9 years. The 2-year freedom from BM was 90.5%. Persistent lymph node positivity, HR 8.75 (1.76-43.52, P = 0.01), and lack of downstaging, HR 3.46 (1.03-11.62, P = 0.04), were significant predictors for BM. The 2-year rate of BM was 0%, 10.7%, and 30.3% (P < 0.001) in patients belonging to low-, intermediate-, and high-risk groups, respectively. Area under the ROC curve was 0.81 (P < 0.001). This model was externally validated (C-index = 0.79). CONCLUSIONS: Lack of downstaging and persistent lymph node positivity after NAC are associated with development of BM in TNBC. This model can be used by the clinicians to stratify patients into the three risk groups to identify those at increased risk of developing BM and potentially impact surveillance strategies.

Downregulation of SPARC Is Associated with Epithelial-Mesenchymal Transition and Low Differentiation State of Biliary Tract Cancer Cells.

BACKGROUND: Biliary tract cancers (BTCs) have a poor prognosis. BTCs are characterized by a prominent desmoplastic reaction which possibly contributes to the aggressive phenotype of this tumor. The desmoplastic reaction includes excessive production and deposition of extracellular matrix proteins such as periostin, secreted protein acidic and rich in cysteine (SPARC), thrombospondin-1, as well as accumulation of α-smooth muscle actin-positive cancer-associated fibroblasts and immune cells, secreting growth factors and cytokines including transforming growth factor (TGF)-ß. In the present study, we investigated the expression of SPARC in BTC as well as its possible regulation by TGF-ß. METHODS: Expression levels of Sparc, TGF-ß1 and its receptor ALK5 were evaluated by quantitative real-time PCR in 6 biliary tract cell lines as well as 1 immortalized cholangiocyte cell line (MMNK-1). RNAs from tumor samples of 7 biliary tract cancer patients were analyzed for expression of Sparc, TGF-ß type II receptor (TbRII) as well as Twist and ZO-1. MMNK-1 cells were stimulated with TGF-ß for 24 h, and Sparc, ZO-1 and E-Cadherin expressions were determined. The presence of SPARC protein was analyzed by immunohistochemistry in tumor specimens from 10 patients. RESULTS: When comparing basal Sparc transcript levels in diverse BTC cell lines to MMNK-1 cells, we found that it was strongly downregulated in all cancer cell lines. The remaining expression levels were higher in highly differentiated cell lines (CCSW1, MZChA1, MZChA2 and TFK-1) than in less differentiated and undifferentiated ones (BDC, SKChA1). Expression of Sparc in BTC patient samples showed a significant positive correlation with expression of the epithelial marker ZO-1. In contrast, the mesenchymal marker Twist and the TbRII showed a trend of negative correlation with expression of Sparc in these samples. TGF-ß exposure significantly downregulated Sparc expression in MMNK-1 cholangiocytes in vitro in parallel to downregulation of epithelial markers (E-Cadherin and ZO-1). Finally, SPARC immunostaining was performed in 10 patient samples, and the correlation between absence of SPARC and survival times was analyzed. CONCLUSIONS: These data imply that a decrease in SPARC expression is correlated with dedifferentiation of BTC cells resulting in enhanced EMT being possibly mediated by TGF-ß. Thereby SPARC levels might be a marker for individual prognosis of a patient, and strategies aiming at inhibition of SPARC downregulation might have potential for new future therapies.

Regulation of Drug Metabolism by the Interplay of Inflammatory Signaling, Steatosis, and Xeno-Sensing Receptors in HepaRG Cells.

Nonalcoholic fatty liver disease (NAFLD), which is characterized by triglyceride deposition in hepatocytes resulting from imbalanced lipid homeostasis, is of increasing concern in Western countries, along with progression to nonalcoholic steatohepatitis (NASH), liver fibrosis, and cirrhosis. Previous studies suggest a complex, mutual influence of hepatic fat accumulation, NASH-related inflammatory mediators, and drug-sensing receptors regulating xenobiotic metabolism. Here, we investigated the suitability of human HepaRG hepatocarcinoma cells as a model for NAFLD and NASH. Cells were incubated for up to 14 days with an oleate/palmitate mixture (125 µM each) and/or with 10 ng/ml of the inflammatory mediator interleukin-6 (IL-6). Effects of these conditions on the regulation of drug metabolism were studied using xenobiotic agonists of the aryl hydrocarbon receptor (AHR), pregnane X receptor (PXR), constitutive androstane receptor (CAR), nuclear factor (erythroid-derived 2)-like 2, and peroxisome proliferator-activated receptor α (PPARα). Results underpin the suitability of HepaRG cells for NAFLD- and NASH-related research and constitute a broad-based analysis of the impact of hepatic fatty acid accumulation and inflammation on drug metabolism and its inducibility by xenobiotics. IL-6 exerted pronounced negative regulatory effects on basal as well as on PXR-, CAR-, and PPARα-, but not AHR-dependent induction of drug-metabolizing enzymes. This inhibition was related to diminished transactivation potential of the respective receptors rather than to reduced transcription of nuclear receptor-encoding mRNAs. The most striking effects of IL-6 and/or fatty acid treatment were observed in HepaRG cells after 14 days of treatment, making these cultures appear a suitable model for studying the relationship of fatty acid accumulation, inflammation, and xenobiotic-induced drug metabolism.

The formation of estrogen-like tamoxifen metabolites and their influence on enzyme activity and gene expression of ADME genes.

Tamoxifen, a standard therapy for breast cancer, is metabolized to compounds with anti-estrogenic as well as estrogen-like action at the estrogen receptor. Little is known about the formation of estrogen-like metabolites and their biological impact. Thus, we characterized the estrogen-like metabolites tamoxifen bisphenol and metabolite E for their metabolic pathway and their influence on cytochrome P450 activity and ADME gene expression. The formation of tamoxifen bisphenol and metabolite E was studied in human liver microsomes and Supersomes™. Cellular metabolism and impact on CYP enzymes was analyzed in upcyte® hepatocytes. The influence of 5 µM of tamoxifen, anti-estrogenic and estrogen-like metabolites on CYP activity was measured by HPLC MS/MS and on ADME gene expression using RT-PCR analyses. Metabolite E was formed from tamoxifen by CYP2C19, 3A and 1A2 and from desmethyltamoxifen by CYP2D6, 1A2 and 3A. Tamoxifen bisphenol was mainly formed from (E)- and (Z)-metabolite E by CYP2B6 and CYP2C19, respectively. Regarding phase II metabolism, UGT2B7, 1A8 and 1A3 showed highest activity in glucuronidation of tamoxifen bisphenol and metabolite E. Anti-estrogenic metabolites (Z)-4-hydroxytamoxifen, (Z)-endoxifen and (Z)-norendoxifen inhibited the activity of CYP2C enzymes while tamoxifen bisphenol consistently induced CYPs similar to rifampicin and phenobarbital. On the transcript level, highest induction up to 5.6-fold was observed for CYP3A4 by tamoxifen, (Z)-4-hydroxytamoxifen, tamoxifen bisphenol and (E)-metabolite E. Estrogen-like tamoxifen metabolites are formed in CYP-dependent reactions and are further metabolized by glucuronidation. The induction of CYP activity by tamoxifen bisphenol and the inhibition of CYP2C enzymes by anti-estrogenic metabolites may lead to drug-drug-interactions.

Confounding influence of tamoxifen in mouse models of Cre recombinase-induced gene activity or modulation.

Tamoxifen (TAM) is commonly used for cell type specific Cre recombinase-induced gene inactivation and in cell fate tracing studies. Inducing a gene knockout by TAM and using non-TAM exposed mice as controls lead to a situation where differences are interpreted as consequences of the gene knockout but in reality result from TAM-induced changes in hepatic metabolism. The degree to which TAM may compromise the interpretation of animal experiments with inducible gene expression still has to be elucidated. Here, we report that TAM strongly attenuates CCl4-induced hepatotoxicity in male C57Bl/6N mice, even after a 10 days TAM exposure-free period. TAM decreased (p < 0.0001) the necrosis index and the level of aspartate- and alanine transaminases in CCl4-treated compared to vehicle-exposed mice. TAM pretreatment also led to the downregulation of CYP2E1 (p = 0.0045) in mouse liver tissue, and lowered its activity in CYP2E1 expressing HepG2 cell line. Furthermore, TAM increased the level of the antioxidant ascorbate, catalase, SOD2, and methionine, as well as phase II metabolizing enzymes GSTM1 and UGT1A1 in CCl4-treated livers. Finally, we found that TAM increased the presence of resident macrophages and recruitment of immune cells in necrotic areas of the livers as indicated by F4/80 and CD45 staining. In conclusion, we reveal that TAM increases liver resistance to CCl4-induced toxicity. This finding is of high relevance for studies using the tamoxifen-inducible expression system particularly if this system is used in combination with hepatotoxic compounds such as CCl4.

A putative Leishmania DNA polymerase theta protects the parasite against oxidative damage.

Leishmania infantum is a protozoan parasite that is phagocytized by human macrophages. The host macrophages kill the parasite by generating oxidative compounds that induce DNA damage. We have identified, purified and biochemically characterized a DNA polymerase θ from L. infantum (LiPolθ), demonstrating that it is a DNA-dependent DNA polymerase involved in translesion synthesis of 8oxoG, abasic sites and thymine glycol lesions. Stably transfected L. infantum parasites expressing LiPolθ were significantly more resistant to oxidative and interstrand cross-linking agents, e.g. hydrogen peroxide, cisplatin and mitomycin C. Moreover, LiPolθ-overexpressing parasites showed an increased infectivity toward its natural macrophage host. Therefore, we propose that LiPolθ is a translesion synthesis polymerase involved in parasite DNA damage tolerance, to confer resistance against macrophage aggression.