Elzbieta Janda

Researcher of Molecular Biology

Name Elzbieta
Surname Janda
Institution University Magna Graecia, Catanzaro
Telephone +39 0961 369 4143
E-Mail janda@unicz.it
Address Department of Health Sciences University Magna Graecia, Catanzaro Campus Germaneto Edificio Bioscienze, livello 5 88100 Catanzaro, Italy
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Elzbieta Janda


  • Microglial Phagocytosis and Its Regulation: A Therapeutic Target in Parkinson's Disease?

    Publication Date: 27/04/2018 on Frontiers in molecular neuroscience
    by Janda E, Boi L, Carta AR
    DOI: 10.3389/fnmol.2018.00144

    The role of phagocytosis in the neuroprotective function of microglia has been appreciated for a long time, but only more recently a dysregulation of this process has been recognized in Parkinson's disease (PD). Indeed, microglia play several critical roles in central nervous system (CNS), such as clearance of dying neurons and pathogens as well as immunomodulation, and to fulfill these complex tasks they engage distinct phenotypes. Regulation of phenotypic plasticity and phagocytosis in microglia can be impaired by defects in molecular machinery regulating critical homeostatic mechanisms, including autophagy. Here, we briefly summarize current knowledge on molecular mechanisms of microglia phagocytosis, and the neuro-pathological role of microglia in PD. Then we focus more in detail on the possible functional role of microglial phagocytosis in the pathogenesis and progression of PD. Evidence in support of either a beneficial or deleterious role of phagocytosis in dopaminergic degeneration is reported. Altered expression of target-recognizing receptors and lysosomal receptor CD68, as well as the emerging determinant role of α-synuclein (α-SYN) in phagocytic function is discussed. We finally discuss the rationale to consider phagocytic processes as a therapeutic target to prevent or slow down dopaminergic degeneration.

  • Analysis of proautophagic activities of Citrus flavonoids in liver cells reveals the superiority of a natural polyphenol mixture over pure flavones.

    Publication Date: 26/04/2018 on The Journal of nutritional biochemistry
    by Lascala A, Martino C, Parafati M, Salerno R, Oliverio M, Pellegrino D, Mollace V, Janda E
    DOI: 10.1016/j.jnutbio.2018.04.005

    Autophagy dysfunction has been implicated in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Natural compounds present in bergamot polyphenol fraction (BPF) prevent NAFLD and induce autophagy in rat livers. Here, we employed HepG2 cells expressing DsRed-LC3-GFP, a highly sensitive model system to screen for proautophagic compounds present in BPF. BPF induced autophagy in a time- and dose-dependent fashion and the effect was amplified in cells loaded with palmitic acid. Autophagy was mediated by the hydrophobic fraction of acid-hydrolyzed BPF (A-BPF), containing six flavanone and flavone aglycones as identified by liquid chromatography-high-resolution mass spectrometry. Among them, naringenin, hesperitin, eriodictyol and diosmetin were weak inducers of autophagy. Apigenin showed the strongest and dose-dependent proautophagic activity at early time points (6 h). Luteolin induced a biphasic autophagic response, strong at low doses and inhibitory at higher doses. Both flavones were toxic in HepG2 cells and in differentiated human liver progenitors HepaRG upon longer treatments (24 h). In contrast, BPF and A-BPF did not show any toxicity, but induced a persistent increase in autophagic flux. A mixture of six synthetic aglycones mimicking A-BPF was sufficient to induce a similar autophagic response, but it was mildly cytotoxic. Thus, while six main BPF flavonoids fully account for its proautophagic activity, their combined effect is not sufficient to abrogate cytotoxicity of individual compounds. This suggests that a natural polyphenol phytocomplex, such as BPF, is a safer and more effective strategy for the treatment of NAFLD than the use of pure flavonoids.

  • Boosting phagocytosis and anti-inflammatory phenotype in microglia mediates neuroprotection by PPARγ agonist MDG548 in Parkinson's disease.

    Publication Date: 23/03/2018 on British journal of pharmacology
    by Lecca D, Janda E, Mulas G, Diana A, Martino C, Angius F, Spolitu S, Antonietta Casu M, Simbula G, Boi L, Batetta B, Spiga S, Carta AR
    DOI: 10.1111/bph.14214

    Microglia phenotype and phagocytic activity are deregulated in Parkinson's disease (PD). Peroxisome proliferator-activated receptor gamma (PPARγ) agonists are neuroprotective in experimental PD, but their role in regulating microglial phenotype and phagocytosis has been poorly investigated. We addressed it by using the PPARγ agonist MDG548.

  • Medicinal Herbs and Their Active Compounds for Fatty Liver Diseases.

    Publication Date: 01/01/2017 on Evidence-based complementary and alternative medicine : eCAM
    by Son CG, Wei Z, Raghavendran HB, Wang JH, Janda E
    DOI: 10.1155/2017/3612478
  • Bergamot polyphenol fraction prevents nonalcoholic fatty liver disease via stimulation of lipophagy in cafeteria diet-induced rat model of metabolic syndrome.

    Publication Date: 01/09/2015 on The Journal of nutritional biochemistry
    by Parafati M, Lascala A, Morittu VM, Trimboli F, Rizzuto A, Brunelli E, Coscarelli F, Costa N, Britti D, Ehrlich J, Isidoro C, Mollace V, Janda E
    DOI: 10.1016/j.jnutbio.2015.03.008

    Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in industrialized countries. Defective autophagy of lipid droplets (LDs) in hepatocytes, also known as lipophagy, has recently been identified as a possible pathophysiological mechanism of NAFLD. Experimental and epidemiological evidence suggests that dietary polyphenols may prevent NAFLD. To address this hypothesis and analyze the underlying mechanisms, we supplemented bergamot polyphenol fraction (BPF) to cafeteria (CAF) diet-fed rats, a good model for pediatric metabolic syndrome and NAFLD. BPF treatment (50 mg/kg/day supplemented with drinking water, 3 months) potently counteracted the pathogenic increase of serum triglycerides and had moderate effects on blood glucose and obesity in this animal model. Importantly, BPF strongly reduced hepatic steatosis as documented by a significant decrease in total lipid content (-41.3% ± 12% S.E.M.), ultrasound examination and histological analysis of liver sections. The morphometric analysis of oil-red stained sections confirmed a dramatic reduction in LDs parameters such as total LD area (48.5% ± 15% S.E.M.) in hepatocytes from CAF+BPF rats. BPF-treated livers showed increased levels of LC3 and Beclin 1 and reduction of SQSTM1/p62, suggesting autophagy stimulation. Consistent with BPF stimulation of lipophagy, higher levels of LC3II were found in the LD subcellular fractions of BPF-expose livers. This study demonstrates that the liver and its lipid metabolism are the main targets of bergamot flavonoids, supporting the concept that supplementation of BPF is an effective strategy to prevent NAFLD.

  • Parkinsonian toxin-induced oxidative stress inhibits basal autophagy in astrocytes via NQO2/quinone oxidoreductase 2: Implications for neuroprotection.

    Publication Date: 01/01/2015 on Autophagy
    by Janda E, Lascala A, Carresi C, Parafati M, Aprigliano S, Russo V, Savoia C, Ziviani E, Musolino V, Morani F, Isidoro C, Mollace V
    DOI: 10.1080/15548627.2015.1058683

    Oxidative stress (OS) stimulates autophagy in different cellular systems, but it remains controversial if this rule can be generalized. We have analyzed the effect of chronic OS induced by the parkinsonian toxin paraquat (PQ) on autophagy in astrocytoma cells and primary astrocytes, which represent the first cellular target of neurotoxins in the brain. PQ decreased the basal levels of LC3-II and LC3-positive vesicles, and its colocalization with lysosomal markers, both in the absence and presence of chloroquine. This was paralleled by increased number and size of SQSTM1/p62 aggregates. Downregulation of autophagy was also observed in cells chronically exposed to hydrogen peroxide or nonlethal concentrations of PQ, and it was associated with a reduced astrocyte capability to protect dopaminergic cells from OS in co-cultures. Surprisingly, PQ treatment led to inhibition of MTOR, activation of MAPK8/JNK1 and MAPK1/ERK2-MAPK3/ERK1 and upregulation of BECN1/Beclin 1 expression, all signals typically correlating with induction of autophagy. Reduction of OS by NMDPEF, a specific NQO2 inhibitor, but not by N-acetylcysteine, abrogated the inhibitory effect of PQ and restored autophagic flux. Activation of NQO2 by PQ or menadione and genetic manipulation of its expression confirmed the role of this enzyme in the inhibitory action of PQ on autophagy. PQ did not induce NFE2L2/NRF2, but when it was co-administered with NMDPEF NFE2L2 activity was enhanced in a SQSTM1-independent fashion. Thus, a prolonged OS in astrocytes inhibits LC3 lipidation and impairs autophagosome formation and autophagic flux, in spite of concomitant activation of several pro-autophagic signals. These findings outline an unanticipated neuroprotective role of astrocyte autophagy and identify in NQO2 a novel pharmacological target for its positive modulation.

  • Bergamot polyphenolic fraction enhances rosuvastatin-induced effect on LDL-cholesterol, LOX-1 expression and protein kinase B phosphorylation in patients with hyperlipidemia.

    Publication Date: 10/12/2013 on International journal of cardiology
    by Gliozzi M, Walker R, Muscoli S, Vitale C, Gratteri S, Carresi C, Musolino V, Russo V, Janda E, Ragusa S, Aloe A, Palma E, Muscoli C, Romeo F, Mollace V
    DOI: 10.1016/j.ijcard.2013.08.125

    Statins are the most commonly prescribed drugs to reduce cardiometabolic risk. Besides the well-known efficacy of such compounds in both preventing and treating cardiometabolic disorders, some patients experience statin-induced side effects. We hypothesize that the use of natural bergamot-derived polyphenols may allow patients undergoing statin treatment to reduce effective doses while achieving target lipid values. The aim of the present study is to investigate the occurrence of an enhanced effect of bergamot-derived polyphenolic fraction (BPF) on rosuvastatin-induced hypolipidemic and vasoprotective response in patients with mixed hyperlipidemia.

  • The antidote effect of quinone oxidoreductase 2 inhibitor against paraquat-induced toxicity in vitro and in vivo.

    Publication Date: 01/01/2013 on British journal of pharmacology
    by Janda E, Parafati M, Aprigliano S, Carresi C, Visalli V, Sacco I, Ventrice D, Mega T, Vadalá N, Rinaldi S, Musolino V, Palma E, Gratteri S, Rotiroti D, Mollace V
    DOI: 10.1111/j.1476-5381.2012.01870.x

    BACKGROUND AND PURPOSE The mechanisms of paraquat (PQ)-induced toxicity are poorly understood and PQ poisoning is often fatal due to a lack of effective antidotes. In this study we report the effects of N-[2-(2-methoxy-6H-dipyrido{2,3-a:3,2-e}pyrrolizin-11-yl)ethyl]-2-furamide (NMDPEF), a melatonin-related inhibitor of quinone oxidoreductase2 (QR2) on the toxicity of PQ in vitro & in vivo. EXPERIMENTAL APPROACH Prevention of PQ-induced toxicity was tested in different cells, including primary pneumocytes and astroglial U373 cells. Cell death and reactive oxygen species (ROS) were analysed by flow cytometry and fluorescent probes. QR2 silencing was achieved by lentiviral shRNAs. PQ (30 mg·kg(-1)) and NMDPEF were administered i.p. to Wistar rats and animals were monitored for 28 days. PQ toxicity in the substantia nigra (SN) was tested by a localized microinfusion and electrocorticography. QR2 activity was measured by fluorimetry of N-benzyldihydronicotinamide oxidation. KEY RESULTS NMDPEF potently antagonized non-apoptotic PQ-induced cell death, ROS generation and inhibited cellular QR2 activity. In contrast, the cytoprotective effect of melatonin and apocynin was limited and transient compared with NMDPEF. Silencing of QR2 attenuated PQ-induced cell death and reduced the efficacy of NMDPEF. Significantly, NMDPEF (4.5 mg·kg(-1)) potently antagonized PQ-induced systemic toxicity and animal mortality. Microinfusion of NMDPEF into SN prevented severe behavioural and electrocortical effects of PQ which correlated with inhibition of malondialdehyde accumulation in cells and tissues. CONCLUSIONS AND IMPLICATIONS NMDPEF protected against PQ-induced toxicity in vitro and in vivo, suggesting a key role for QR2 in the regulation of oxidative stress.

  • Defective autophagy in Parkinson's disease: role of oxidative stress.

    Publication Date: 01/12/2012 on Molecular neurobiology
    by Janda E, Isidoro C, Carresi C, Mollace V
    DOI: 10.1007/s12035-012-8318-1

    Parkinson's disease (PD) is a paradigmatic example of neurodegenerative disorder with a critical role of oxidative stress in its etiopathogenesis. Genetic susceptibility factors of PD, such as mutations in Parkin, PTEN-induced kinase 1, and DJ-1 as well as the exposure to pesticides and heavy metals, both contribute to altered redox balance and degeneration of dopaminergic neurons in the substantia nigra. Dysregulation of autophagy, a lysosomal-driven process of self degradation of cellular organelles and protein aggregates, is also implicated in PD and PD-related mutations, and environmental toxins deregulate autophagy. However, experimental evidence suggests a complex and ambiguous role of autophagy in PD since either impaired or abnormally upregulated autophagic flux has been shown to cause neuronal loss. Finally, it is generally believed that oxidative stress is a strong proautophagic stimulus. However, some evidence coming from neurobiology as well as from other fields indicate an inhibitory role of reactive oxygen species and reactive nitrogen species on the autophagic machinery. This review examines the scientific evidence supporting different concepts on how autophagy is dysregulated in PD and attempts to reconcile apparently contradictory views on the role of oxidative stress in autophagy regulation. The complex relationship between autophagy and oxidative stress is also considered in the context of the ongoing search for a novel PD therapy.

  • The protective effect of tianeptine on Gp120-induced apoptosis in astroglial cells: role of GS and NOS, and NF-κB suppression.

    Publication Date: 01/11/2011 on British journal of pharmacology
    by Janda E, Visalli V, Colica C, Aprigliano S, Musolino V, Vadalà N, Muscoli C, Sacco I, Iannone M, Rotiroti D, Spedding M, Mollace V
    DOI: 10.1111/j.1476-5381.2010.01172.x

    Tianeptine is an antidepressant affecting the glutamatergic system. In spite of its proven clinical efficacy, molecular effects of tianeptine are not entirely clear. Tianeptine modulates cytokine expression in the CNS and protects the hippocampus from chronic stress effects. HIV infection is associated with inflammation and neuronal loss, causing HIV-associated dementia (HAD). The human immunodeficiency virus type-1 glycoprotein gp120 has been proposed as a likely aetiological agent of HAD. In this study, we determined whether tianeptine protects astroglial cells from the neurodegenerative effects of gp120.