Assessing the toxicity of pesticides exposure on hepatic miRNA-target gene alterations in rat liver tissues via molecular and integrated network bioinformatics analysis.

The prevalent use of pesticides, including pirimiphos-methyl (PPM) and bifenthrin (BF), poses a serious health risk, particularly to workers who encounter these chemicals daily. Despite the recognized hepatotoxic effects, the specific molecular mechanisms, especially those involving miRNAs in liver damage caused by PPM and BF, are not fully elucidated. Prior studies have not exhaustively analyzed the hepatic miRNA-target gene dynamics following exposure to these pesticides; thus, this research aims to fill that gap through an extensive miRNA analysis to discern their regulation in PPM or BF-induced hepatic toxicity. In this study, male Sprague-Dawley rats were exposed to BF or PPM for 28 days through oral gavage, simulating the chronic exposure faced by humans. We conducted a thorough assessment of the hepatotoxicity induced by PPM and BF, employing multiple evaluation levels, including histological analysis, liver enzyme measurements, and real-time PCR to detect changes in hepatic miRNA-target gene expressions. Additionally, we utilized DIANA-miRPath prediction tools to delineate the functional implications of these hepatic miRNA target genes. Our findings reveal a significant modulation in the expression of rno-miR-155-5p and rno-miR-122-5p, along with their target genes, following PPM and BF treatment. In contrast, rno-miR-21-5p levels remained unaltered. These observations suggest potential utility of these specific hepatic miRNAs as biomarkers for liver injury resulting from pesticide exposure. Subsequent GO enrichment analysis linked target genes to functions like molecular activity, protein binding, and cellular processes. Additionally, KEGG pathway analysis showed these genes, influenced by varied miRNA expressions, play significant roles in metabolic and signaling pathways In conclusion, this study enhances our comprehension of the biological roles of miRNAs in hepatic toxicity induced by PPM and BF. The insights gained here not only shed light on molecular mechanisms but also open avenues for considering these miRNAs as potential diagnostic biomarkers in conditions of pesticide-induced hepatotoxicity, thereby guiding future therapeutic strategies.

IL-6 at the center of cytokine storm: Circulating inflammation mediators as biomarkers in hospitalized COVID-19 patients.

INTRODUCTION: The management of hospitalized COVID-19 patients depends largely on controlling the intensified inflammatory response known as the cytokine storm. Candidate inflammatory cytokines can serve as new biomarkers for the management of hospitalized COVID-19 patients. METHODS: Patients (80) were recruited into three groups: room air (RA), oxygen (OX) and mechanical ventilator (MV). Blood analysis was performed for RBC, WBC, Hb, Platelets, serum albumin and creatinine, INR, PTT, and hematocrit. ELISA was used to quantify a panel of inflammatory mediators including GM-SCF, IFN-α, IFNγ, IL-1ß, IL-1R, IL-2, IL-2Ra, IL-6, IL-8, IL-10, IL-12p70, IL-13, MCP-1, MIP-1a, and TNF-α. Correlations between laboratory results and the levels of circulating inflammation mediators were investigated. RESULTS: Patients on MV had low RBC, Hb, albumin, and HCT and high WBC count, PTT, and INR when compared to RA and OX groups. A statistical positive correlation was found between WBC and the levels of IL-6 and MCP-1. RBCs correlated negatively with IL-6 and IL-10 and positively with IL-8. Higher TNF-α correlated with lower platelet counts while higher levels of IL-1Rα and IL-10 were associated with lower Hb levels. Increases in IFN-γ and TNF-α were indicative of compromised kidney functions as creatinine levels increased significantly. Most significant correlations were found between IL-6 and lab results, showing positive correlation with WBC and INR, and negative correlation with RBC, albumin, and HCT. CONCLUSIONS: Having the most significant correlations, IL-6 high levels in mechanically ventilated patients were shown to affect laboratory results, and, therefore, is suggested as a severity biomarker of COVID-19.

Alpha-Mangostin ameliorates acute kidney injury via modifying levels of circulating TNF-α and IL-6 in glycerol-induced rhabdomyolysis animal model.

Alpha mangostin (AM), isolated from G. mangostana, showed beneficial effects in several disorders due to its antioxidant and anti-inflammatory properties. Acute kidney injury (AKI) due to different etiologies can develop into severe complications, resulting in high mortality rates. In this work, AM is tested for its ability to alleviate AKI in glycerol-induced AKI rat model, where 30 Male Sprague-Dawley rats were assigned to a healthy group, glycerol-treated group and AM-treated group. Glycerol- and AM groups received a single dose of glycerol (per IM, 50% glycerol in saline, 8 ml/kg), whereas control group was injected with saline. AM treatment (a single daily dose, per IP, 175mg/kg) was accomplished for three days. Animals were executed to collect blood samples and kidney tissue for biochemical and histological examination. It was found that glycerol induced increase in serum creatinine, blood urea nitrogen (BUN), lipid peroxidation, serum magnesium, TNF-α and IL-6. It also induced renal edema and hypocalcemia along with histopathological renal damage. AM treatment improved renal histological features and alleviated increase in serum creatinine, BUN, serum magnesium, TNF-α and IL-6 levels, as well as renal edema and lipid peroxidation but did not affect serum calcium levels. This suggests AM as a potential therapeutic agent for treating AKI mainly via its antioxidant and anti-inflammatory properties.

Identification of Chemo and Radio-Resistant Sub-Population of Stem Cells in Human Cervical Cancer HeLa Cells.

BACKGROUND: Cervical cancer ranks the second female malignancy after breast cancer. Cancer stem cells (CSCs) are hard to be eradicated, so can recur. We aim to isolate and characterize CSCs from HeLa cells. METHODS: These cells express clusters of differentiation (CDs), 44 and 24, to be sorted by fluorescence-activated cell sorting (FACS). RESULTS: CD44+CD24+ cells showed potential to form spheres, tumorigenicity, stemness genes and higher resistance to cisplatin, X-ray. CONCLUSION: CD44+CD24+ HeLa cells hold characteristics of CSCs, in vitro, in vivo studies, suggesting that targeting may lead to screening of new anti-cancer therapies.

Generation of Combinatorial Lentiviral Vectors Expressing Multiple Anti-Hepatitis C Virus shRNAs and Their Validation on a Novel HCV Replicon Double Reporter Cell Line.

Despite the introduction of directly acting antivirals (DAAs), for the treatment of hepatitis C virus (HCV) infection, their cost, patient compliance, and viral resistance are still important issues to be considered. Here, we describe the generation of a novel JFH1-based HCV subgenomic replicon double reporter cell line suitable for testing different antiviral drugs and therapeutic interventions. This cells line allowed a rapid and accurate quantification of cell growth/viability and HCV RNA replication, thus discriminating specific from unspecific antiviral effects caused by DAAs or cytotoxic compounds, respectively. By correlating cell number and virus replication, we could confirm the inhibitory effect on the latter of cell over confluency and characterize an array of lentiviral vectors expressing single, double, or triple cassettes containing different combinations of short hairpin (sh)RNAs, targeting both highly conserved viral genome sequences and cellular factors crucial for HCV replication. While all vectors were effective in reducing HCV replication, the ones targeting viral sequences displayed a stronger antiviral effect, without significant cytopathic effects. Such combinatorial platforms as well as the developed double reporter cell line might find application both in setting-up anti-HCV gene therapy approaches and in studies aimed at further dissecting the viral biology/pathogenesis of infection.

The metabolic disorders associated with chronic consumption of soft and energy drinks in rats.

BACKGROUND: Energy Drinks (EDs) and Soft Drinks (SDs) are widely consumed among adolescents and young adults. These drinks contain variable amounts of caffeine which is a central nervous system stimulator; in addition to sugar, taurine, vitamins and herbal extracts. Several adverse effects have been reported for the excessive consumption of caffeine and sugar. AIM: This work aimed at providing a comparison between the effect of chronic consumption of both drinks on metabolism biochemically as well as at the histopathological level. METHODS: Adult albino rats were randomly divided into three groups and treated for 4 weeks. Animals received water (control, group 1), 12.5 ml/kg/day of either Pepsi® (SD, group 2) or Power Horse® (ED, group 3). All animals had free access to water and standard animal chow. RESULTS: ED and SD groups showed a significant weight gain compared to control. ED animals showed a significant increase in serum urea, hyperlipidemia and hyperglycemia in comparison to control and SD groups. Serum uric acid significantly increased in ED and SD groups. ED group showed congestion and inflammation in their renal tissues in addition to splenomegaly and increased phagocyte infiltration. CONCLUSION: The high caffeine-sugar content in ED exerts a more significant influence on the metabolic pathways than SDs. Both increase the incidence of cardiovascular diseases and tissue inflammation due to their effect on lipid profile and blood glucose. The other ingredients in EDs may play a role in the observed metabolic disturbances. Chronic use of EDs should be especially discouraged to avoid these negative effects.

Antioxidant, anti-inflammatory and anti-fibrotic effects of Boswellia serrate gum resin in CCl4-induced hepatotoxicity.

The present study aims to investigate the potential antioxidant, anti-inflammatory and anti-fibrotic effects of Boswellia serrate (BS) gum resin against carbon tetrachloride (CCl4)-induced liver damage. Four groups consisting of eight rats each were designated: Group I, normal healthy control; group II, CCl4-induced liver fibrosis; group III, CCl4-induced liver fibrosis followed by BS treatment daily for two weeks; and group IV, CCl4-induced liver fibrosis followed by silymarin treatment daily for two weeks. Expression of tumor necrosis factor-α (TNF-α) and nuclear factor κB (NF-κB), interleukin-6 (IL-6), transforming growth factor-ß (TGF-ß) and cyclooxygenase-2 (COX-2) were assessed, in addition to histopathological and fibrotic changes in liver tissues isolated from the rats. BS significantly ameliorated CCl4-induced increases in serum aspartate (AST) and alanine transaminase (ALT) levels, reduced lactate dehydrogenase (LDH) activities in addition to restoring total bilirubin, triglyceride and albumin levels. BS treatment also alleviated oxidative stress and improved total antioxidant capacity in the liver, and reduced the expression of TNF-α, NF-κB, TGF-ß, IL-6 and COX-2. On a histopathological level, BS treatment also exhibited antifibrotic activity. In conclusion, these findings suggest that BS contains potentially hepatoprotective effects against CCl4-induced liver injury via its antioxidant, anti-inflammatory and antifibrotic characteristics.

A study of the hepatoprotective effect of Plantago psyllium L. seed extract against Carbon tetrachloride induced hepatic injury in rats.

BACKGROUND: The liver is the main metabolic organ involved in disposal and detoxification of various molecules. Plantago psyllium L. seed has been reported to exert positive effects in some pathological conditions. The current study aims to assess the hepatoprotective effect of Plantago psyllium L. seed extract against carbon tetrachloride-induced hepatotoxicity. METHODS: Male albino Wistar rats were randomly divided into five groups of 10 rats each. Hepatotoxicity was induced by orally administered carbon tetrachloride (CCl4) for nine weeks with or without the different treatments which were utilized daily for the whole nine weeks. Serum and tissue samples were then withdrawn and different liver biomarkers were investigated. RESULTS: Treatment of rats with Psyllium seed ethanolic extract significantly alleviated the toxic effects of CCl4. This was evidenced by its ability to restore liver biomarkers levels. Moreover, treatment with Psyllium seed extract normalized levels of oxidative biomarkers such as lipid peroxidation, hepatic content of reduced glutathione and catalase activity, as well as the expression level of the inflammatory marker TNF-α. Histopathological examination reflected the protective effect of the extract on liver architecture and confirmed the observed biochemical data. CONCLUSIONS: The presented data demonstrates a potential hepatoprotective effect of Psyllium seed extract compared to the standard hepatoprotective drug silymarin. This effect can be attributed to the antioxidant and anti-inflammatory effects of Psyllium extract.

Molecular Mechanisms of Natural Honey Against H. pylori Infection Via Suppression of NF-κB and AP-1 Activation in Gastric Epithelial Cells.

BACKGROUND AND AIMS: Natural honey has been used as a medicine since ancient times. Honey is widely known for its antibacterial properties against H. pylori; however, the mechanisms of its antibacterial activity are not fully known. The present study was performed to examine the molecular mechanisms by which natural honey can inhibit H. pylori infection in gastric epithelial cells. METHODS: Electrophoretic mobility shift assay was used to measure NF-κB- and AP-1-DNA binding activity. Western blotting was used to detect IκB-α and COX-2 expression. RESULTS: H. pylori induced NF-κB and AP-1 DNA-binding activity in gastric epithelial cells. Manuka honey inhibited H. pylori-induced NF-κB and AP-1 in a time- and dose-dependent manner. Maximum inhibition of H. pylori-induced NF-κB and AP-1 by manuka honey was observed at concentrations of 20% at 1-2 h. Pre-treatment of AGS cells with other commercial natural honeys also inhibited H. pylori-induced NF-κB and AP-1 DNA-binding activity. Honey prevented H. pylori-induced degradation of IκB-α protein and downregulated COX-2 protein levels. CONCLUSIONS: Our findings suggest that natural honey exerts its inhibitory effects against H. pylori by inhibiting NF-κB and AP-1 activation and downregulation of COX-2 expression. These results provide new mechanistic insights into honey effects in the suppression of H. pylori infection.

Hepatoprotective activity of ethanolic extract of Salix subserrata against CCl4-induced chronic hepatotoxicity in rats.

BACKGROUND: The liver performs diverse functions that are essential for life. In the absence of reliable liver protective drugs, a large number of natural medicinal preparations are used for the treatment of liver diseases. Therefore the present study aims to investigate the hepatoprotective effects of Salix subserrata Willd flower ethanolic extract (SFEE) against carbon tetrachloride (CCl4)-induced liver damage. METHODS: Rats were divided into 4 groups of 10 animals each. Group I served as the normal healthy control, groups II rats were intoxicated with CCl4 i.p. (0.8 ml/kg body weight CCl4/olive oil, twice weekly for 9 weeks), group III rats received CCl4 i.p. and SFEE orally (150 mg/kg daily) and group IV rats received CCl4 i.p. and Silymarin orally (100 mg/kg, daily). The hepatoprotective potential of SFEE in rats was evaluated by measuring the protein levels of two inflammatory biomarkers; tumor necrosis factor-alpha (TNF-α) and nuclear factor kappa-B (NF-kB) in addition to other liver biomarkers. Histopathological changes in the liver were assessed using hematoxylin and eosin staining (HE). RESULTS: The administration of SFEE showed hepatic protection at an oral dose of 150 mg/kg. SFEE significantly reduced the elevated serum levels of intracellular liver enzymes as well as liver biomarkers in comparison to CCl4- intoxicated group. Notably, SFEE significantly reduced the expression levels of TNF-α and NFkB proteins compared to their levels in CCl4 intoxicated group. These findings were confirmed with the histopathological observations, where SFEE was capable of reversing the toxic effects of CCl4 on liver cells compared to that observed in CCl4-intoxicated animals. CONCLUSION: Our results show that SFEE has potential hepatoprotective effects at 150 mg/kg. These effects can be regarded to the antioxidant and anti-inflammatory properties of the extract.

Experimental evidence for the therapeutic potential of tempol in the treatment of acute liver injury.

Oxidative stress is one of the mechanisms involved in the acute carbon tetrachloride (CCl4)-induced hepatotoxicity. Since 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, known as tempol, has powerful antioxidant properties, we investigated its potential hepatoprotective effects and the underlying mechanisms that may add further benefits for its clinical usefulness using an acute model of CCl4-induced hepatotoxicity. One hour after CCl4 induction of acute hepatotoxicity, mice were treated with a daily dose of 20 mg/kg/day tempol for 3 days. It was found that treatment of animals with tempol significantly negated the pathological changes in liver function parameters as well as histology induced by CCl4. In addition, tempol significantly ameliorated CCl4-induced lipid peroxidation and GSH depletion, and improved catalase activity. Furthermore, tempol alleviated the inflammation induced by CCl4 as indicated by reducing the liver expression level of nuclear factor-kappa B (NF-κB) and tumor necrosis factor-α (TNF-α). Finally, tempol significantly reduced expression level of the B-cell lymphoma-2 protein (Bcl-2) and active caspase-3 which are known markers of apoptosis. In conclusion, the present study provides important evidences for the promising hepatoprotective effects of tempol that can be explained by amelioration of oxidative stress mainly through replenishment of GSH, restoration of antioxidant enzyme activities, and reduction of lipid peroxides alongside its anti-inflammatory properties.

Comparative effects of Aliskiren and Telmisartan in high fructose diet-induced metabolic syndrome in rats.

Fructose is a commonly used sweetener associated with diets that increase the prevalence of metabolic syndrome (MS). Inhibition of the renin-angiotensin system (RAS) has been consistently demonstrated to reduce MS. However, there has been no direct comparison among different pharmacological modes of inhibiting the RAS concerning their effects on MS. This study investigated the effect of aliskiren, a direct renin inhibitor, versus telmisartan, an angiotensin II-receptor blocker, in the treatment of fructose-induced MS in rats. MS was induced by high fructose (FRC) diet feeding for 12 weeks. Oral administrations of telmisartan (TEL, 5 mg/kg), aliskiren (ALS, 30 mg/kg) or vehicle were started in the last 4 weeks. Results showed that administration of either TEL or ALS with FRC diet equally ameliorated the metabolic parameters (glucose level, oral glucose tolerance test, insulin resistance and serum lipids profile), systolic blood pressure and oxidative stress markers (malondialdehyde, nitric oxide, reduced glutathione levels and catalase activity). Additionally, the effects of TEL and ALS were associated with a decrease in body composition index and attenuation of liver index, serum liver enzyme activities and hepatic expressions of inflammatory and fibrotic markers (tumor necrosis factor-α, nuclear factor kappa-B and transforming growth factor-ß) with a significant increase in hepatic glucose transporter-2 and peroxisome proliferator-activated receptors-alpha and gamma expressions. The results suggested that, at indicated dosage, ALS has ameliorative effect equal to that of TEL against FRC-induced metabolic and hepatic disorders; implying that drugs which inhibit the RAS, by different mode of inhibition, profoundly affect fructose-induced MS in rats.

Estimation of leucine aminopeptidase and 5-nucleotidase increases alpha-fetoprotein sensitivity in human hepatocellular carcinoma cases.

PURPOSE: To find parameters that can increase alpha-fetoprotein (AFP) sensitivity and so help in accurate diagnosis and rapid management of hepatocullular carcinoma (HCC), as AFP has limited utility of distinguishing HCC from benign hepatic disorders for its high false-positive and false negative rates. MATERIALS AND METHODS: Serum levels of AFP, 5'-nucleotidase enzyme activity (5-NU) and leucine aminopeptidase enzyme (LAP) activity were measured in 40 individuals. RESULTS: LAP and 5'NU were elevated in HCC at p<0.001. Pearson correlation coefficients showed that changes in AFP exhibited positive correlation with both 5'-NU and LAP at (p<0.001). The complementary use of LAP only with AFP resulted in an increase in sensitivity of AFP from 75% to 90% in detecting HCC. The complementary use of both LAP and 5-NU with AFP resulted in an increased sensitivity of AFP in detecting HCC from 75% to 95%. CONCLUSIONS: LAP and 5-FU can be determined in HCC patients in combination with AFP to improve its sensitivity and decrease false negative results.

Curcumin ameliorate DENA-induced HCC via modulating TGF-ß, AKT, and caspase-3 expression in experimental rat model.

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. In laboratory animal models, diethylnitrosamine (DENA) is a well-known agent that has a potent hepatocarcinogenic effect that is used to induce HCC. As curcumin has a potent anti-inflammatory effect with strong therapeutic potential against a variety of cancers, our present study aims to investigate its curative effects and the possible mechanisms of action against DENA-induced HCC in male rats. Investigation of biochemical and molecular parameters of HCC animal model liver showed an overexpression of TGF-ß and Akt proteins accompanied with a significant reduction of the proapoptotic marker caspase-3. DENA-induced hepatic cellular injury resulted also in a significant increase in liver function marker enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lipid peroxides in this group. Curcumin treatment partially reversed DENA-induced damage as it reduced the overexpression of the angiogenic and anti-apoptotic factors TGF-ß and Akt and improved caspase-3 expression. Also, it could partially normalize the serum values of liver marker enzymes and lipid peroxidation and improve liver architecture. Curcumin shows a unique chemotherapeutic effect in reversing DENA-induced HCC in rat model. This effect is possibly mediated through its proapoptotic, antioxidant, anti-angiogenic, as well as antimitotic effects. It interferes and modulates cell signaling pathways and hence turns death signals and apoptosis on within tumor cells.

Tempol ameliorates cardiac fibrosis in streptozotocin-induced diabetic rats: role of oxidative stress in diabetic cardiomyopathy.

Long-standing diabetes is associated with increased oxidative stress and cardiac fibrosis. This, in turn, contributes to the progression of cardiomyopathy. The present study was sought to investigate whether the free radical scavenger, 4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl (tempol) can protect against diabetic cardiomyopathy and to explore the specific underlying mechanism(s) in this setting. Diabetes was induced in rats by a single intraperitoneal injection dose of streptozotocin (50 mg/kg). These animals were treated with tempol (18 mg kg(-1) day(-1), orally) for 8 weeks. Our results showed significant increases in collagen IV and fibronectin protein levels and a marked decrease in matrix metalloproteinase-2 (MMP-2) activity measured by gelatin-gel zymography alongside elevated cardiac transforming growth factor (TGF)-ß level determined using ELISA or immunohistochemistry in cardiac tissues of diabetic rats compared with control. This was accompanied by an increased in the oxidative stress as evidenced by increased reactive oxygen species (ROS) production and decreased antioxidant enzyme capacity along with elevated lactate dehydrogenase (LDH) and creatine kinase (CK-MB) serum levels as compared with the control. Tempol treatment significantly corrected the changes in the cardiac extracellular matrix, TGF-ß, ROS or serum LDH, CK-MB levels, and normalized MMP-2 activity along with preservation of cardiac tissues integrity of diabetic rats against damaging responses. Moreover, tempol normalized the elevated systolic blood pressure and improved some cardiac functions in diabetic rats. Collectively, our data suggest a potential protective role of tempol against diabetes-associated cardiac fibrosis in rats via reducing oxidative stress and extracellular matrix remodeling.

Cardioprotective effects of nicorandil, a mitochondrial potassium channel opener against doxorubicin-induced cardiotoxicity in rats.

Doxorubicin is a chemotherapeutic drug used to treat solid and haematopoietic tumours. Its use is limited by a major side effect of cardiotoxicity. It was reported that doxorubicin-induced cardiotoxicity is mediated through oxidative stress coupled with impaired NO bioavailability and NF-κB activation. Nicorandil, a mitochondrial ATP-dependent potassium (KATP ) channel opener, was reported to be cardioprotective on ischaemic myocardium. However, the effect of nicorandil against doxorubicin-induced cardiotoxicity has not yet been clarified. Accordingly, six groups of rats were used. The first three groups were injected with vehicle, nicorandil (3 mg/kg) orally and doxorubicin (a single intraperitoneal injection of 20 mg/kg), respectively. Group four was treated with nicorandil, whereas group five was treated with glibenclamide and then nicorandil starting 2 days before doxorubicin and continued for five consecutive days. Group six was treated with glibenclamide alone. At the end of the experiment, the rats were killed. Cardiac enzyme indexes were measured in serum. Heart tissues were processed for determination of nitrite/nitrate, NF-κB protein expression, glutathione (GSH), lipid peroxide (TBARS) levels and superoxide production. In addition to body-weight reduction, doxorubicin produced cardiotoxicity as indicated from the increase in lactate dehydrogenase (LDH), creatine kinase (CK) activities, TBARS, superoxide production, NF-κB expression and caspase-3 activity. Moreover, doxorubicin decreased GSH and nitrite/nitrate levels. Histopathological examination of doxorubicin-treated hearts revealed degenerative changes. On the other hand, nicorandil protected cardiac tissues against doxorubicin cardiotoxicity as demonstrated from normalization of cardiac biochemical and oxidative stress parameters and amelioration of histopathological changes. Glibenclamide, a blocker of the KATP channel, reversed most of the cardiac effects of nicorandil.

Hepatoma-derived growth factor and nucleolin exist in the same ribonucleoprotein complex.

BACKGROUND: Hepatoma-derived growth factor (HDGF) is a protein which is highly expressed in a variety of tumours. HDGF has mitogenic, angiogenic, neurotrophic and antiapoptotic activity but the molecular mechanisms by which it exerts these activities are largely unknown nor has its biological function in tumours been elucidated. Mass spectrometry was performed to analyse the HDGFStrep-tag interactome. By Pull-down-experiments using different protein and nucleic acid constructs the interaction of HDGF and nucleolin was investigated further. RESULTS: A number of HDGFStrep-tag copurifying proteins were identified which interact with RNA or are involved in the cellular DNA repair machinery. The most abundant protein, however, copurifying with HDGF in this approach was nucleolin. Therefore we focus on the characterization of the interaction of HDGF and nucleolin in this study. We show that expression of a cytosolic variant of HDGF causes a redistribution of nucleolin into the cytoplasm. Furthermore, formation of HDGF/nucleolin complexes depends on bcl-2 mRNA. Overexpression of full length bcl-2 mRNA increases the number of HDGF/nucleolin complexes whereas expression of only the bcl-2 coding sequence abolishes interaction completely. Further examination reveals that the coding sequence of bcl-2 mRNA together with either the 5' or 3' UTR is sufficient for formation of HDGF/nucleolin complexes. When bcl-2 coding sequence within the full length cDNA is replaced by a sequence coding for secretory alkaline phosphatase complex formation is not enhanced. CONCLUSION: The results provide evidence for the existence of HDGF and nucleolin containing nucleoprotein complexes which formation depends on the presence of specific mRNAs. The nature of these RNAs and other components of the complexes should be investigated in future.

Overexpression of hepatoma-derived growth factor in melanocytes does not lead to oncogenic transformation.

BACKGROUND: HDGF is a growth factor which is overexpressed in a wide range of tumors. Importantly, expression levels were identified as a prognostic marker in some types of cancer such as melanoma. METHODS: To investigate the presumed oncogenic/transforming capacity of HDGF, we generated transgenic mice overexpressing HDGF in melanocytes. These mice were bred with mice heterozygous for a defective copy of the Ink4a tumor suppressor gene and were exposed to UV light to increase the risk for tumor development both genetically and physiochemically. Mice were analyzed by immunohistochemistry and Western blotting. Furthermore, primary melanocytes were isolated from different strains created. RESULTS: Transgenic animals overexpressed HDGF in hair follicle melanocytes. Interestingly, primary melanocytes isolated from transgenic animals were not able to differentiate in vitro whereas cells isolated from wild type and HDGF-deficient animals were. Although, HDGF-/-/Ink4a+/- mice displayed an increased number of epidermoid cysts after exposure to UV light, no melanomas or premelanocytic alterations could be detected in this mouse model. CONCLUSIONS: The results therefore provide no evidence that HDGF has a transforming capacity in tumor development. Our results in combination with previous findings point to a possible role in cell differentiation and suggest that HDGF promotes tumor progression after secondary upregulation and may represent another protein fitting into the concept of non-oncogene addiction of tumor tissue.

Hepatoma-derived growth factor-related protein-3: a new neurotrophic and neurite outgrowth-promoting factor for cortical neurons.

Hepatoma-derived growth factor-related proteins (HRPs) make up a family of six members. Hepatoma-derived growth factor-related protein-3 (HRP-3) is the only family member whose expression is almost restricted to nervous tissue. Here we show that soluble HRP-3 acts as a novel neurotrophic factor for cultured primary cortical neurons. Antibody-mediated neutralization of HRP-3 function results in neuronal degeneration. In contrast, HRP-3 as the only addition to a culture medium not supporting neuronal survival rescues neurons to an extent comparable to the addition of FCS. Besides this neuroprotective capability, the protein exerts a neurite outgrowth-promoting effect when it is presented as a coated substrate but not as a soluble factor. This study points to an important role of HRP-3 during the development of the nervous system.

Misfolded endoplasmic reticulum retained subunits cause degradation of wild-type subunits of arylsulfatase A heteromers.

Arylsulfatase A is an oligomeric lysosomal enzyme. In the present study, we use this enzyme as a model protein to examine how heteromerization of wild-type and misfolded endoplasmic reticulum-degraded arylsulfatase A polypeptides affects the quality control of wild-type arylsulfatase A subunits. Using a conformation sensitive monoclonal antibody, we show that, within heteromers of misfolded and wild-type arylsulfatase A, the wild-type subunits are not fully folded. The results obtained show that arylsulfatase A polypeptide complexes, rather than the monomers, are subject to endoplasmic reticulum quality control and that, within a heteromer, the misfolded subunit exerts a dominant negative effect on the wild-type subunit. Although it has been shown that mature lysosomal arylsulfatase A forms dimers at neutral pH, the results obtained in the present study demonstrate that, in the early biosynthetic pathway, arylsulfatase A forms oligomers with more than two subunits.