Impact of text contrast polarity on the retinal activity in myopes and emmetropes using modified pattern ERG.

Environmental factors favoring myopia development are still being studied and there is accumulating evidence for a significant role of nearwork. Recently, reading standard black-on-white text was found to activate the retinal OFF pathway and induce choroidal thinning, which is associated with myopia onset. Contrarily, reading white-on-black text led to thicker choroids, being protective against myopia. Respective effects on retinal processing are yet unknown. Here, we exploratively assessed the impact of contrast polarity on the retinal activity and possible interactions with eccentricity and refractive error. We recorded pattern electroretinograms in myopic and emmetropic adults while presenting a dead leaves stimulus (DLS), overlaid by masks of different size in ring or circle shape, either filled with uniform gray or text of inverted or standard contrast. In myopes, retinal responses for DLS with standard and inverted contrast were larger when the perifovea was stimulated (6-12 deg), however, including the fovea resulted in smaller amplitudes for inverted contrast than in emmetropes. The retina of emmetropes was more sensitive to inverted contrast than to standard and gray within 12 deg, but most sensitive for gray in the perifovea. This demonstrates that the refractive error influences the sensitivity to text contrast polarity, with a special role of the peripheral retina, which is in line with previous studies about blur sensitivity. Defining whether the differences derive from retinal processing or anatomical features of a myopic eye requires further investigation. Our approach might be a first step to explain how nearwork promotes the eye's elongation.

Tumour-Derived Cell Lines and Their Potential for Therapy Prediction in Patients with Metastatic Colorectal Cancer.

The prognosis of metastatic colorectal cancer (CRC) remains poor. Patients and physicians are in need of individual therapies and precise response predictions. We investigated the predictive capacity of primary tumour material for treatment response of metastases. Mutational landscapes of primary tumours and corresponding metastases of 10 CRC patients were compared. Cell line characteristics and chemosensitivity were investigated pairwise for primary and metastatic tumours of four patients. PDX models of one patient were treated in vivo for proof of concept. Driver mutations did not differ between primaries and metastases, while the latter accumulated additional mutations. In vitro chemosensitivity testing revealed no differences for responses to 5-FU and oxaliplatin between primary and metastatic cell lines. However, irinotecan response differed significantly: the majority of metastases-derived cell lines was less sensitive to irinotecan than their matching primary counterpart. Therapy recommendations based on these findings were compared to clinical treatment response and mostly in line with the predicted outcome. Therefore, primary tumour cell models seem to be a good tool for drug response testing and conclusion drawing for later metastases. With further data from tumour-derived cell models, such predictions could improve clinical treatment decisions, both recommending likely effective therapeutic options while excluding ineffective treatments.

APOBEC3A catalyzes mutation and drives carcinogenesis in vivo.

The APOBEC3 family of antiviral DNA cytosine deaminases is implicated as the second largest source of mutation in cancer. This mutational process may be a causal driver or inconsequential passenger to the overall tumor phenotype. We show that human APOBEC3A expression in murine colon and liver tissues increases tumorigenesis. All other APOBEC3 family members, including APOBEC3B, fail to promote liver tumor formation. Tumor DNA sequences from APOBEC3A-expressing animals display hallmark APOBEC signature mutations in TCA/T motifs. Bioinformatic comparisons of the observed APOBEC3A mutation signature in murine tumors, previously reported APOBEC3A and APOBEC3B mutation signatures in yeast, and reanalyzed APOBEC mutation signatures in human tumor datasets support cause-and-effect relationships for APOBEC3A-catalyzed deamination and mutagenesis in driving multiple human cancers.

Sleeping Beauty Insertional Mutagenesis Reveals Important Genetic Drivers of Central Nervous System Embryonal Tumors.

Medulloblastoma and central nervous system primitive neuroectodermal tumors (CNS-PNET) are aggressive, poorly differentiated brain tumors with limited effective therapies. Using Sleeping Beauty (SB) transposon mutagenesis, we identified novel genetic drivers of medulloblastoma and CNS-PNET. Cross-species gene expression analyses classified SB-driven tumors into distinct medulloblastoma and CNS-PNET subgroups, indicating they resemble human Sonic hedgehog and group 3 and 4 medulloblastoma and CNS neuroblastoma with FOXR2 activation. This represents the first genetically induced mouse model of CNS-PNET and a rare model of group 3 and 4 medulloblastoma. We identified several putative proto-oncogenes including Arhgap36, Megf10, and Foxr2. Genetic manipulation of these genes demonstrated a robust impact on tumorigenesis in vitro and in vivo. We also determined that FOXR2 interacts with N-MYC, increases C-MYC protein stability, and activates FAK/SRC signaling. Altogether, our study identified several promising therapeutic targets in medulloblastoma and CNS-PNET. SIGNIFICANCE: A transposon-induced mouse model identifies several novel genetic drivers and potential therapeutic targets in medulloblastoma and CNS-PNET.

Hyponatremia and MAP-kinase inhibitors in malignant melanoma: Frequency, pathophysiological aspects and clinical consequences.

The incidence of malignant melanoma has increased over the past two decades. A combined BRAF/MEK inhibitor regimen has been shown to lead to prolonged survival and progression-free survival in patients with metastatic BRAF V600-mutant melanoma. Different nephrotoxic effects have been described, among them hyponatremia. The goal of the present narrative review was to understand the pathophysiological mechanisms driving hyponatremia when using selective BRAF inhibitors and/or MEK inhibitors in order to propose potential strategies to prevent or to treat this side effect. Several mechanisms of kidney injury have been suggested including changes in glomerular and tubular function. However, the precise mechanisms of hyponatremia remain unknown. Our hypothesis is that BRAF/MEK inhibitors lead to hyponatremia and water retention (so-called dilution hyponatremia) by activating aquaporin 2 (AQP2) trafficking from its intracellular compartment to the luminal cell membrane, and by activating ENaC channel. Therefore, we recommend treating the hyponatremia related to BRAF/MEK inhibitors with restriction of fluid intake.

Colorectal cancer vaccines: Tumor-associated antigens vs neoantigens.

Therapeutic options for the treatment of colorectal cancer (CRC) are diverse but still not always satisfying. Recent success of immune checkpoint inhibition treatment for the subgroup of CRC patients suffering from hyper-mutated tumors suggests a permanent role of immune therapy in the clinical management of CRC. Substantial improvement in treatment outcome could be achieved by development of efficient patient-individual CRC vaccination strategies. This mini-review summarizes the current knowledge on the two general classes of targets: tumor-associated antigens (TAAs) and tumor-specific antigens. TAAs like carcinoembryonic antigen and melanoma associated antigen are present in and shared by a subgroup of patients and a variety of clinical studies examined the efficacy of different TAA-derived peptide vaccines. Combinations of several TAAs as the next step and the development of personalized TAA-based peptide vaccines are discussed. Improvements of peptide-based vaccines achievable by adjuvants and immune-stimulatory chemotherapeutics are highlighted. Finally, we sum up clinical studies using tumor-specific antigens - in CRC almost exclusively neoantigens - which revealed promising results; particularly no severe adverse events were reported so far. Critical progress for clinical outcomes can be expected by individualizing neoantigen-based peptide vaccines and combining them with immune-stimulatory chemotherapeutics and immune checkpoint inhibitors. In light of these data and latest developments, truly personalized neoantigen-based peptide vaccines can be expected to fulfill modern precision medicine's requirements and will manifest as treatment pillar for routine clinical management of CRC.

Factors associated with the introduction of complementary feeding in the French ELFE cohort study.

The objectives of this study were to estimate the age of complementary feeding introduction (CFI) and investigate the related health, demographic, and socio-economic factors. Analyses were based on 10,931 infants from the French national birth cohort ELFE, born in 2011. Health, demographic, and socio-economic data concerning infants and parents were collected at birth (face-to-face interviews and medical records) and 2 months (telephone interviews). Data on milk feeding and CFI practices were collected at birth and 2 months then monthly from 3 to 10 months using online or paper questionnaires. The associations between both health and social factors and CFI age were tested by multivariable multinomial logistic regressions. The mean CFI age was 5.2 ± 1.2 months; 26% of the infants started complementary feeding before 4 months of age (CF < 4 months), 62% between 4 and 6 months of age, and 12% after 6 months of age (CF > 6 months). CF < 4 months was more likely when mothers smoked, were overweight/obese, younger (<29 years), and used their personal experience as an information source in child caregiving and when both parents were not born in France. CF < 4 months was less likely when the infant was a girl, second-born, when the mother breastfed longer, and had attended at least one birth preparation class. Mothers of second-born infants and who breastfed their child longer were more likely to introduce CF > 6 months. Couples in which fathers were born in France and mothers were not born in France were less likely to introduce CF > 6 months. CF < 4 months occurred in more than 25% of the cases. It is important to continue promoting clear CFI recommendations, especially in smoking, overweight, young, not born in France, and nonbreastfeeding mothers.

Sleeping Beauty Insertional Mutagenesis in Mice Identifies Drivers of Steatosis-Associated Hepatic Tumors.

Hepatic steatosis is a strong risk factor for the development of hepatocellular carcinoma (HCC), yet little is known about the molecular pathology associated with this factor. In this study, we performed a forward genetic screen using Sleeping Beauty (SB) transposon insertional mutagenesis in mice treated to induce hepatic steatosis and compared the results to human HCC data. In humans, we determined that steatosis increased the proportion of female HCC patients, a pattern also reflected in mice. Our genetic screen identified 203 candidate steatosis-associated HCC genes, many of which are altered in human HCC and are members of established HCC-driving signaling pathways. The protein kinase A/cyclic AMP signaling pathway was altered frequently in mouse and human steatosis-associated HCC. We found that activated PKA expression drove steatosis-specific liver tumorigenesis in a mouse model. Another candidate HCC driver, the N-acetyltransferase NAT10, which we found to be overexpressed in human steatosis-associated HCC and associated with decreased survival in human HCC, also drove liver tumorigenesis in a steatotic mouse model. This study identifies genes and pathways promoting HCC that may represent novel targets for prevention and treatment in the context of hepatic steatosis, an area of rapidly growing clinical significance. Cancer Res; 77(23); 6576-88. ©2017 AACR.

Association of plasma potassium with mortality and end-stage kidney disease in patients with chronic kidney disease under nephrologist care - The NephroTest study.

BACKGROUND: Low and high blood potassium levels are common and were both associated with poor outcomes in patients with chronic kidney disease (CKD). Whether such relationships may be altered in CKD patients receiving optimized nephrologist care is unknown. METHODS: NephroTest is a hospital-based prospective cohort study that enrolled 2078 nondialysis patients (mean age: 59 ± 15 years, 66% men) in CKD stages 1 to 5 who underwent repeated extensive renal tests including plasma potassium (PK) and glomerular filtration rate (GFR) measured (mGFR) by 51Cr-EDTA renal clearance. Test reports included a reminder of recommended targets for each abnormal value to guide treatment adjustment. Main outcomes were cardiovascular (CV) and all-cause mortality before end-stage kidney disease (ESKD), and ESKD. RESULTS: At baseline, median mGFR was 38.4 mL/min/1.73m2; prevalence of low PK (<4 mmol/L) was 26.5%, and of high PK (>5 mmol/L) 6.4%; 74.4% of patients used angiotensin converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB). After excluding 137 patients with baseline GFR < 10 mL/min/1.73m2 or lost to follow-up, 459 ESKD events and 236 deaths before ESKD (83 CV deaths) occurred during a median follow-up of 5 years. Compared to patients with PK within [4, 5] mmol/L at baseline, those with low PK had hazard ratios (HRs) [95% CI] for all-cause and CV mortality before ESKD, and for ESKD of 0.82 [0.58-1.16], 1.01 [0.52-1.95], and 1.14 [0.89-1.47], respectively, with corresponding figures for those with high PK of 0.79 [0.48-1.32], 1.5 [0.69-3.3], and 0.92 [0.70-1.21]. Considering time-varying PK did not materially change these findings, except for the HR of ESKD associated with high PK, 1.39 [1.09-1.78]. Among 1190 patients with at least two visits, PK had normalized at the second visit in 39.9 and 54.1% respectively of those with baseline low and high PK. Among those with low PK that normalized, ARB or ACEi use increased between the visits (68.3% vs 81.8%, P < .0001), and among those with high PK that normalized, potassium-binding resin and bicarbonate use increased (13.0% vs 37.0%, P < .001, and 4.4% vs 17.4%, P = 0.01, respectively) without decreased ACEi or ARB use. CONCLUSION: In these patients under nephrology care, neither low nor high PK was associated with excess mortality.

The measured glomerular filtration rate (mGFR) before and 6 months after bariatric surgery: A pilot study.

INTRODUCTION: Over the last few decades, the prevalence of obesity has increased dramatically. This increase has been mirrored by a rise in the risk of a number of health conditions, including hypertension, diabetes and chronic kidney disease. Although the weight loss following bariatric surgery has been shown to relieve the severity of diabetes and reduce hypertension, the effect on renal function has been less extensively evaluated. OBJECTIVE: The aims of the present study were to: (i) compare the estimated glomerular filtration rate (eGFR, using the MDRD and CKD-EPI equations) and the calculated glomerular filtration rate (using the 24-hour urine volume) with the measured glomerular filtration rate (mGFR) assessed with the plasma iohexol clearance method in severely obese patients, and (ii) evaluate the effect of weight loss on the mGFR 6 months after bariatric surgery. METHODS: Before and six months after bariatric surgery (Roux-en-Y gastric bypass or sleeve gastrectomy), eligible patients for bariatric surgery were admitted as day cases to the nephrology unit, where they underwent a plasma iohexol clearance test. The GFR was also estimated using the MDRD and CKDEPI equations and the 24-hour urine method. Changes in eGFR and mGFR were compared using a Wilcoxon test for paired data. RESULTS: Data from 16 patients with severe obesity (mean ± standard deviation of Body Mass Index [BMI]: 43.9 ± 7.3 kg/m2) were analyzed. At baseline, 12 (75%) presented with hypertension and 10 (63%) presented with diabetes. The median [range] iohexol clearance rate was 109 [57-194] mL/min. The plasma iohexol clearance test evidenced hyperfiltration (mGFR>120 mL/min) in 7 patients. In contrast, the eGFR values generated by the MDRD equation, the CKDEPI equation and the GFR MFR calculated with the 24-hour urine method only identified hyperfiltration in 1, 0 and 5 patients, respectively. Six months after surgery, the mean BMI had fallen significantly (P<0.0012), and the severity of diabetes (according to the HbA1c level) had decreased significantly from 6.6 [6.0-9.8] % to 5.7 [5.2-8.6] % (P=0.025). The iohexol clearance rate increased slightly after bariatric surgery. Changes in BMI after surgery do not seem to be correlated with the changes in iohexol clearance. In patients displaying hyperfiltration at baseline, the mGFR fell significantly (n=7; P=0.01) and returned to near normal values. No significant changes in the eGFR were observed. CONCLUSION: Our results suggest that MDRD and CKD-EPI equations do not provide accurate estimates of the true GFR in severely obese patients (particularly in those with hyperfiltration). Iohexol clearance or other methods for determining mGFR should constitute the gold standard for the accurate evaluation of renal function in this context. Renal function (as evaluated by the mGFR) improved 6 months after bariatric surgery in severely obese individuals particularly in patients displaying hyperfiltration at baseline. However, these observations must be confirmed in a larger study with a longer follow-up period.

Preoperative Evaluation of the Renal Function before the Treatment of Abdominal Aortic Aneurysms.

BACKGROUND: Chronic impaired renal function constitutes a major risk factor of morbi-mortality during the treatment of an abdominal aortic aneurism (AAA). The inflammatory state due to the AAA could result in a reduction in the muscular mass and an overestimation of the glomerular filtration rate (GFR) with the usual formulas. The objective of this study was to determine if the formulas used to evaluate the estimated GFR were adapted in patients with AAA. MATERIALS AND METHODS: Between August 2013 and November 2014, we conducted an exploratory study to evaluate the renal function before surgery for AAA in 28 patients. The renal function was evaluated by (1) the dosage of plasmatic creatinine, (2) the GFR estimated with the Cockroft-Gault, Modification of Diet in Renal Disease (MDRD), and chronic kidney disease epidemiology collaboration (CKD-EPI) formulas, (3) the creatinine clearance (CC), and (4) the direct measurement of the GFR with a reference method (iohexol clearance). Statistical analysis was carried out to compare and correlate the GFR estimated by the various formulas with the GFR measured by the reference technique. RESULTS: The study included 21 men (75%) and 7 women (25%), with a median age of 76 years (58-89). The measured GFR was correlated with the GFR estimated from the CKD-EPI (rho = 0.78, P < 0.0001), the MDRD (rho = 0.78, P < 0.0001), the Cockroft-Gault (rho = 0.65, P = 0.0002), and CC (rho = 0.86, P < 0.0001). However, there were important individual variations between estimated and measured GFR. As regards the detection of the patients presenting a GFR <60 mL/min/1.73 m2, the sensitivities of the CKD-EPI, MDRD, Cockroft-Gault formulas and CC were 64%, 64%, 71%, and 70%, respectively. Specificities were 71%, 79%, 57%, and 100%, respectively. The estimation of the GFR by the CKD-EPI formula had the lowest bias (-3.0). Bland-Altman plots indicated that the estimation of the GFR by the CKD-EPI formula had the best performance in comparison with the other methods. CONCLUSIONS: This study found a statistical correlation between the measurement of the GFR and the various formulas available to estimation the GFR among AAA patients. The CKD-EPI formula is most appropriate. However, there were important individual variations between the measurement and the estimations of the GFR. A larger scale study is necessary to determine the profile of the patients with a risk of error in the estimation of the GFR. The French recommendations on the evaluation of the renal function before AAA treatment remain based on serum creatinine and should be revalued.

A systems biology approach reveals the dose- and time-dependent effect of primary human airway epithelium tissue culture after exposure to cigarette smoke in vitro.

To establish a relevant in vitro model for systems toxicology-based mechanistic assessment of environmental stressors such as cigarette smoke (CS), we exposed human organotypic bronchial epithelial tissue cultures at the air liquid interface (ALI) to various CS doses. Previously, we compared in vitro gene expression changes with published human airway epithelia in vivo data to assess their similarities. Here, we present a follow-up evaluation of these in vitro transcriptomics data, using complementary computational approaches and an integrated mRNA-microRNA (miRNA) analysis. The main cellular pathways perturbed by CS exposure were related to stress responses (oxidative stress and xenobiotic metabolism), inflammation (inhibition of nuclear factor-κB and the interferon gamma-dependent pathway), and proliferation/differentiation. Within post-exposure periods up to 48 hours, a transient kinetic response was observed at lower CS doses, whereas higher doses resulted in more sustained responses. In conclusion, this systems toxicology approach has potential for product testing according to "21st Century Toxicology".

Characterization of the Vitrocell® 24/48 in vitro aerosol exposure system using mainstream cigarette smoke.

BACKGROUND: Only a few exposure systems are presently available that enable cigarette smoke exposure of living cells at the air-liquid interface, of which one of the most versatile is the Vitrocell® system (Vitrocell® Systems GmbH). To assess its performance and optimize the exposure conditions, we characterized a Vitrocell® 24/48 system connected to a 30-port carousel smoking machine. The Vitrocell® 24/48 system allows for simultaneous exposure of 48 cell culture inserts using dilution airflow rates of 0-3.0 L/min and exposes six inserts per dilution. These flow rates represent cigarette smoke concentrations of 7-100%. RESULTS: By characterizing the exposure inside the Vitrocell® 24/48, we verified that (I) the cigarette smoke aerosol distribution is uniform across all inserts, (II) the utility of Vitrocell® crystal quartz microbalances for determining the online deposition of particle mass on the inserts, and (III) the amount of particles deposited per surface area and the amounts of trapped carbonyls and nicotine were concentration dependent. At a fixed dilution airflow of 0.5 L/min, the results showed a coefficient of variation of 12.2% between inserts of the Vitrocell® 24/48 module, excluding variations caused by different runs. Although nicotine and carbonyl concentrations were linear over the tested dilution range, particle mass deposition increased nonlinearly. The observed effect on cell viability was well-correlated with increasing concentration of cigarette smoke. CONCLUSIONS: Overall, the obtained results highlight the suitability of the Vitrocell® 24/48 system to assess the effect of cigarette smoke on cells under air-liquid interface exposure conditions, which is closely related to the conditions occurring in human airways.

Human bronchial epithelial cells exposed in vitro to cigarette smoke at the air-liquid interface resemble bronchial epithelium from human smokers.

Organotypic culture of human primary bronchial epithelial cells is a useful in vitro system to study normal biological processes and lung disease mechanisms, to develop new therapies, and to assess the biological perturbations induced by environmental pollutants. Herein, we investigate whether the perturbations induced by cigarette smoke (CS) and observed in the epithelium of smokers' airways are reproducible in this in vitro system (AIR-100 tissue), which has been shown to recapitulate most of the characteristics of the human bronchial epithelium. Human AIR-100 tissues were exposed to mainstream CS for 7, 14, 21, or 28 min at the air-liquid interface, and we investigated various biological endpoints [e.g., gene expression and microRNA profiles, matrix metalloproteinase 1 (MMP-1) release] at multiple postexposure time points (0.5, 2, 4, 24, 48 h). By performing a Gene Set Enrichment Analysis, we observed a significant enrichment of human smokers' bronchial epithelium gene signatures derived from different public transcriptomics datasets in CS-exposed AIR-100 tissue. Comparison of in vitro microRNA profiles with microRNA data from healthy smokers highlighted various highly translatable microRNAs associated with inflammation or with cell cycle processes that are known to be perturbed by CS in lung tissue. We also found a dose-dependent increase of MMP-1 release by AIR-100 tissue 48 h after CS exposure in agreement with the known effect of CS on this collagenase expression in smokers' tissues. In conclusion, a similar biological perturbation than the one observed in vivo in smokers' airway epithelium could be induced after a single CS exposure of a human organotypic bronchial epithelium-like tissue culture.

Enhanced expression of MMP-7 and MMP-13 in inflammatory bowel disease: a precancerous potential?

Matrix metalloproteinases (MMPs) are responsible for the turnover and degradation of extracellular matrix. They play a crucial role in the growth and migration of colorectal carcinoma cells. Colorectal carcinomas are characterized by enhanced expression of MMP-2, MMP-9, MMP-7, and MMP-13. The aim of this study was to determine the expression levels of MMP-2, MMP-9, MMP-7, MMP-13, and MMP-14 and their specific inhibitor TIMP-1 in inflammatory bowel diseases and precancerous lesions of the colon, i.e., Crohn's disease and ulcerative colitis, and in adenomatous polyps (APs) for comparison. Biopsy samples of pathological and healthy tissue were obtained from 40 patients with inflammatory bowel disease (ulcerative colitis, n = 17; Crohn's disease, n = 23) and from 19 patients with APs. mRNA was measured by quantitative real-time polymerase chain reaction to study MMP and TIMP-1 gene expression in both pathological and normal mucosal specimens. For MMP-2, MMP-9, and TIMP-1, protein expression also was quantified with sandwich enzyme-linked immunosorbent assay. In biopsy specimens of Crohn's disease and ulcerative colitis, significantly increased levels of MMP-2, MMP-7, and MMP-13 mRNA were found. MMP-2 and MMP-9 showed enhanced secretion on the protein level. AP revealed an increased transcription of MMP-7 and MMP-13 genes. MMP-14 mRNA was decreased in APs. MMPs, especially MMP-7 and MMP-13, which are expressed primarily on the tumor cell surface, are elevated in inflammatory bowel disease, which may have more chance to evolve into malignancy than normal tissue. In APs, increased expression of MMP-7 and MMP-13 may serve as an early indicator for colorectal carcinogenesis.

Inhibition of hepatic fibrogenesis by matrix metalloproteinase-9 mutants in mice.

Tissue inhibitor of metalloproteinases-1 (TIMP-1) plays a crucial role in the pathogenesis of hepatic fibrosis and thus may represent an important therapeutic target in the design of anti-fibrotic strategies for chronic liver disease. We present an innovative therapy based on the assignment of inactivated enzymes acting as scavengers for TIMP-1. Hepatic fibrosis was induced in BALB/c mice by repetitive intraperitoneal CCl4 injection. The animals were treated with proteolytic inactive matrix metalloproteinase-9 mutants (E402Q, H401A, E402H/H411E) using adenovirus-mediated gene transfer. Application of these MMP-9 mutants inhibited fibrogenesis, which was indicated by decreasing portal and periportal accumulation of collagen. Total hydroxyproline of liver tissue, the morphometric stage of fibrosis as well as mRNA expression of marker proteins for hepatic fibrosis in livers of E402Q- and H401A-treated mice were significantly reduced. MMP-9 mutants suppressed transdifferentiation of hepatic stellate cells to the myofibroblast like phenotype in vitro and in vivo. Moreover, adenoviral application of the mutants MMP-9-H401A and -E402Q led to increased apoptosis of activated hepatic stellate cells, thought to be the main promoters of hepatic fibrosis. Application of MMP-9 mutants as TIMP-1 scavengers may provide a new therapeutic strategy for hepatic fibrosis.

Enhanced migration of tissue inhibitor of metalloproteinase overexpressing hepatoma cells is attributed to gelatinases: relevance to intracellular signaling pathways.

AIM: To study the effect of gelatinases (especially MMP-9) on migration of tissue inhibitor of metalloproteinase (TIMP-1) overexpressing hepatoma cells. METHODS: Wild type HepG2 cells, cells stably transfected with TIMP-1 and TIMP-1 antagonist (MMP-9-H401A, a catalytically inactive matrix metalloproteinase (MMP) which still binds and neutralizes TIMP-1) were incubated in Boyden chambers either with or without Galardin (a synthetic inhibitor of MMP-1, -2, -3, -8, -9) or a specific inhibitor of gelatinases. RESULTS: Compared to wild type HepG2 cells, the cells overexpressing TIMP-1 showed 115% migration (P<0.05) and the cells overexpressing MMP-9-H401A showed 62% migration (P<0.01). Galardin reduced cell migration dose dependently in all cases. The gelatinase inhibitor reduced migration in TIMP-1 overexpressing cells predominantly. Furthermore, we examined intracellular signal transduction pathways of TIMP-1-dependent HepG2 cells. TIMP-1 deactivates cell signaling pathways of MMP-2 and MMP-9 involving p38 mitogen-activated protein kinase. Specific blockade of the ERK pathway suppresses gelatinase expression either in the presence or absence of TIMP-1. CONCLUSION: Overexpressing functional TIMP-1- enhanced migration of HepG2-TIMP-1 cells depends on enhanced MMP-activity, especially MMP-9.

Differential effects of histone deacetylase inhibitors on interleukin-18 gene expression in myeloid cells.

Histone deacetyrase (HDAC) inhibitors induce growth arrest and differentiation of leukemia cell lines and tumor cells derived from a large variety of human tissues. Here we showed that HDAC inhibitors sodium butyrate, TSA, and valproate regulated the expression of Interleukin-18 (IL-18), a cytokine with antitumor and proinflammatory properties, in human acute myeloid leukemia cell lines U937 and HEL. Sodium butyrate increased expression of IL-18 protein and mRNA and activated 1357bp IL-18 gene promoter construct. IL-18 mRNA level was up-regulated by TSA or valproate, which also activated IL-18 full-length promoter. While sodium butyrate or TSA stimulated the 108-bp IL-18 minimal promoter, valproate failed to activate it, indicating that valproate may use a distinct mechanism from sodium butyrate and TSA to activate IL-18 gene expression.