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1.
J Cell Sci ; 133(7)2020 04 08.
Article in English | MEDLINE | ID: mdl-32079656

ABSTRACT

Intracellular survival of Leishmania donovani demands rapid production of host ATP for its sustenance. However, a gradual decrease in intracellular ATP in spite of increased glycolysis suggests ATP efflux during infection. Accordingly, upon infection, we show here that ATP is exported and the major exporter was pannexin-1, leading to raised extracellular ATP levels. Extracellular ATP shows a gradual decrease after the initial increase, and analysis of cell surface ATP-degrading enzymes revealed induction of the ectonucleotidases CD39 and CD73. Ectonucleotidase-mediated ATP degradation leads to increased extracellular adenosine (eADO), and inhibition of CD39 and CD73 in infected cells decreased adenosine concentration and parasite survival, documenting the importance of adenosine in infection. Inhibiting adenosine uptake by cells did not affect parasite survival, suggesting that eADO exerts its effect through receptor-mediated signalling. We also show that Leishmania induces the expression of adenosine receptors A2AR and A2BR, both of which are important for anti-inflammatory responses. Treating infected BALB/c mice with CD39 and CD73 inhibitors resulted in decreased parasite burden and increased host-favourable cytokine production. Collectively, these observations indicate that infection-induced ATP is exported, and after conversion into adenosine, propagates infection via receptor-mediated signalling.


Subject(s)
Apyrase , Leishmaniasis , Adenosine , Adenosine Triphosphate , Animals , Antigens, CD/genetics , Apyrase/genetics , Mice , Mice, Inbred BALB C
2.
PLoS Pathog ; 16(8): e1008792, 2020 08.
Article in English | MEDLINE | ID: mdl-32813746

ABSTRACT

Tumor suppressors can exert pro-proliferation functions in specific contexts. In the beta human papillomavirus type 38 (HPV38) experimental model, the viral proteins E6 and E7 promote accumulation of a wild-type (WT) p53 form in human keratinocytes (HKs), promoting cellular proliferation. Inactivation of p53 by different means strongly decreases the proliferation of HPV38 E6/E7 HKs. This p53 form is phosphorylated at S392 by the double-stranded RNA-dependent protein kinase PKR, which is highly activated by HPV38. PKR-mediated S392 p53 phosphorylation promotes the formation of a p53/DNMT1 complex, which inhibits expression of integrin alpha 1 (ITGA1), a repressor of epidermal growth factor receptor (EGFR) signaling. Ectopic expression of ITGA1 in HPV38 E6/E7 HKs promotes EGFR degradation, inhibition of cellular proliferation, and cellular death. Itga1 expression was also inhibited in the skin of HPV38 transgenic mice that have an elevated susceptibility to UV-induced skin carcinogenesis. In summary, these findings reveal the existence of a specific WT p53 form that displays pro-proliferation properties.


Subject(s)
Carrier Proteins/antagonists & inhibitors , Cell Proliferation , Keratinocytes/pathology , Membrane Proteins/antagonists & inhibitors , Oncogene Proteins, Viral/metabolism , Papillomavirus E7 Proteins/metabolism , Papillomavirus Infections/complications , Repressor Proteins/metabolism , Skin Neoplasms/etiology , Tumor Suppressor Protein p53/metabolism , Animals , Cells, Cultured , Down-Regulation , Humans , Keratinocytes/immunology , Keratinocytes/virology , Mice , Mice, Transgenic , Oncogene Proteins, Viral/genetics , Papillomaviridae/isolation & purification , Papillomavirus E7 Proteins/genetics , Papillomavirus Infections/virology , Repressor Proteins/genetics , Skin Neoplasms/metabolism , Skin Neoplasms/pathology , Tumor Suppressor Protein p53/genetics
3.
J Cell Sci ; 132(9)2019 05 02.
Article in English | MEDLINE | ID: mdl-30910830

ABSTRACT

Previously, we documented the role of the programmed death-1 (PD-1, also known as PDCD1) pathway in macrophage apoptosis and the downregulation of this signaling during infection by the intra-macrophage parasite Leishmania donovani However, we also found that, during the late phase of infection, PD-1 expression was significantly increased without activating host cell apoptosis; here we show that inhibition of PD-1 led to markedly decreased parasite survival, along with increased production of TNFα, IL-12, reactive oxygen species (ROS) and nitric oxide (NO). Increased PD-1 led to inactivation of AKT proteins resulting in nuclear sequestration of FOXO-1. Transfecting infected cells with constitutively active FOXO-1 (CA-FOXO) led to increased cell death, thereby suggesting that nuclear FOXO-1 might be inactivated. Infection significantly induced the expression of SIRT1, which inactivated FOXO-1 through deacetylation, and its knockdown led to increased apoptosis. SIRT1 knockdown also significantly decreased parasite survival along with increased production of TNFα, ROS and NO. Administration of the SIRT1 inhibitor sirtinol (10 mg/kg body weight) in infected mice decreased spleen parasite burden and a synergistic effect was found with PD-1 inhibitor. Collectively, our study shows that Leishmania utilizes the SIRT1/FOXO-1 axis for differentially regulating PD-1 signaling and, although they are interconnected, both pathways independently contribute to intracellular parasite survival.This article has an associated First Person interview with the first author of the paper.


Subject(s)
Forkhead Box Protein O1/metabolism , Host-Parasite Interactions , Leishmania donovani , Programmed Cell Death 1 Receptor/metabolism , Sirtuin 1/metabolism , Animals , Apoptosis , Benzamides/pharmacology , Cell Line , Cytokines/metabolism , Disease Progression , Host-Parasite Interactions/immunology , Host-Parasite Interactions/physiology , Immune Evasion/physiology , Leishmania donovani/parasitology , Leishmania donovani/pathogenicity , Leishmaniasis, Visceral/immunology , Leishmaniasis, Visceral/metabolism , Macrophages/metabolism , Mice , Mice, Inbred BALB C , Naphthols/pharmacology , Nitric Oxide/metabolism , Reactive Oxygen Species/metabolism , Signal Transduction , Sirtuin 1/drug effects , Spleen/parasitology , Tumor Necrosis Factor-alpha/metabolism
4.
J Virol ; 94(3)2020 01 17.
Article in English | MEDLINE | ID: mdl-31694959

ABSTRACT

Merkel cell polyomavirus (MCPyV) is the first human polyomavirus etiologically associated with Merkel cell carcinoma (MCC), a rare and aggressive form of skin cancer. Similar to other polyomaviruses, MCPyV encodes early T antigen genes, viral oncogenes required for MCC tumor growth. To identify the unique oncogenic properties of MCPyV, we analyzed the gene expression profiles in human spontaneously immortalized keratinocytes (NIKs) expressing the early genes from six distinct human polyomaviruses (PyVs), including MCPyV. A comparison of the gene expression profiles revealed 28 genes specifically deregulated by MCPyV. In particular, the MCPyV early gene downregulated the expression of the tumor suppressor gene N-myc downstream-regulated gene 1 (NDRG1) in MCPyV gene-expressing NIKs and hTERT-MCPyV gene-expressing human keratinocytes (HK) compared to their expression in the controls. In MCPyV-positive MCC cells, the expression of NDRG1 was downregulated by the MCPyV early gene, as T antigen knockdown rescued the level of NDRG1. In addition, NDRG1 overexpression in hTERT-MCPyV gene-expressing HK or MCC cells resulted in a decrease in the number of cells in S phase and cell proliferation inhibition. Moreover, a decrease in wound healing capacity in hTERT-MCPyV gene-expressing HK was observed. Further analysis revealed that NDRG1 exerts its biological effect in Merkel cell lines by regulating the expression of the cyclin-dependent kinase 2 (CDK2) and cyclin D1 proteins. Overall, NDRG1 plays an important role in MCPyV-induced cellular proliferation.IMPORTANCE Merkel cell carcinoma was first described in 1972 as a neuroendocrine tumor of skin, most cases of which were reported in 2008 to be caused by a PyV named Merkel cell polyomavirus (MCPyV), the first PyV linked to human cancer. Thereafter, numerous studies have been conducted to understand the etiology of this virus-induced carcinogenesis. However, it is still a new field, and much work is needed to understand the molecular pathogenesis of MCC. In the current work, we sought to identify the host genes specifically deregulated by MCPyV, as opposed to other PyVs, in order to better understand the relevance of the genes analyzed on the biological impact and progression of the disease. These findings open newer avenues for targeted drug therapies, thereby providing hope for the management of patients suffering from this highly aggressive cancer.


Subject(s)
Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Cell Movement/genetics , Cell Proliferation/genetics , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Merkel cell polyomavirus/genetics , Merkel cell polyomavirus/physiology , Antigens, Viral, Tumor/genetics , Antigens, Viral, Tumor/metabolism , Carcinogenesis/genetics , Carcinoma, Merkel Cell/virology , Cell Line , Down-Regulation , Gene Expression Regulation, Neoplastic , Gene Expression Regulation, Viral , Humans , Keratinocytes/virology , Polyomavirus Infections/virology , Skin/pathology , Skin Neoplasms/genetics , Transcriptome , Tumor Virus Infections/virology
5.
J Immunol ; 202(3): 827-840, 2019 02 01.
Article in English | MEDLINE | ID: mdl-30593539

ABSTRACT

Suppression of host oxidative burst is essential for survival of the intracellular parasite Leishmania donovani Screening of macrophage antioxidant enzymes during infection revealed marked upregulation of the heme-degrading enzyme, heme oxygenase-1 (HO-1). Moreover, HO-1-silenced RAW macrophages depicted increased superoxide production and decreased parasite survival. HO-1 induction decreased cellular heme content, thereby inhibiting the heme-dependent maturation of gp91phox, a catalytic component of major reactive oxygen species-producing enzyme NAD(P)H oxidase. Decreased gp91phox expression resulted in reduced stability of p22phox, another component of the catalytic center of NAD(P)H oxidase. Replenishing infected cells with exogenous heme reversed these effects and restored NAD(P)H oxidase activity. Persistent HO-1 expression at late hour of infection prompted us to investigate its effect on other host defense parameters, and inhibition study revealed a reciprocal relationship of HO-1 with host proinflammatory responses. Among all the HO-1-mediated heme degradation products (CO, Fe, and biliverdin), only CO documented potent anti-inflammatory effects. Quenching of CO during infection increased the production of disease-resolving cytokines IL-12 and TNF-α. Coimmunoprecipitation experiments revealed that CO inhibited the interaction of TLR4 with MyD88 and TIR domain-containing adapter-inducing IFN-ß, thereby dampening the activation of NF-κB and IFN regulatory factor 3-mediated production of proinflammatory cytokines. Administration of HO-1 inhibitor tin protoporphyrin IX dichloride in infected BALB/c mice led to a decrease in liver and spleen parasite burden along with increased production of IL-12 and TNF-α. These results suggest that HO-1 on one hand inhibits reactive oxygen species generation and on the other hand downregulates host favorable cytokine responses, thereby facilitating intramacrophage parasite survival.


Subject(s)
Heme Oxygenase-1/metabolism , Host-Parasite Interactions , Leishmania donovani/immunology , Macrophages/enzymology , Membrane Proteins/metabolism , Respiratory Burst , Toll-Like Receptor 4/immunology , Animals , Cytokines/immunology , Female , Macrophages/immunology , Macrophages/parasitology , Mice , Mice, Inbred BALB C , NADPH Oxidase 2/metabolism , NADPH Oxidases/metabolism , Parasite Load , Protoporphyrins/administration & dosage , RAW 264.7 Cells , Signal Transduction , Up-Regulation
6.
Int J Cancer ; 147(10): 2862-2870, 2020 11 15.
Article in English | MEDLINE | ID: mdl-32525572

ABSTRACT

To study the interaction between HIV and other carcinogenic infections in conjunctival squamous cell carcinoma (SCC), we evaluated the presence of a broad spectrum of human viruses in conjunctiva specimens. Beta Human papillomavirus (HPV; n = 46), gamma HPV (n = 52), polyomaviruses (n = 12) and herpes viruses (n = 3) was determined in DNA extracted from 67 neoplastic and 55 non-neoplastic conjunctival tissues of HIV-positive and HIV negative subjects by Luminex-based assays. Next-generation sequencing (NGS) was also used to further characterize the presence of cutaneous HPVs. Detection of beta-2 HPV infections was associated with the risk of neoplasia (adjusted odds ratio [aOR] 3.0; 95% confidence interval [CI] 1.3-6.8), regardless of HIV status (HIV positive, aOR 2.6, 95% CI 0.9-7.7; HIV negative, aOR 3.5, 95% CI 0.9-14.4). EBV was strongly associated with the risk of neoplasia (aOR 12.0, 95% CI 4.3-33.5; P < .01) mainly in HIV individuals (HIV positive, aOR 57.5; 95% CI: 10.1-327.1; HIV negative aOR 2.6; 95% CI: 0.2-34.7). NGS allowed to identify 13 putative novel HPVs in cases and controls. Our findings suggest a role of beta HPV types and EBV, in conjunctival SCC. However, additional studies of viral expression in tumor tissue are required to confirm the causal association.


Subject(s)
Carcinoma, Squamous Cell/virology , Conjunctival Neoplasms/virology , HIV Infections/epidemiology , Precancerous Conditions/virology , Sequence Analysis, DNA/methods , Virus Diseases/diagnosis , Adult , Alphapapillomavirus/classification , Alphapapillomavirus/genetics , Alphapapillomavirus/isolation & purification , Case-Control Studies , DNA, Viral/genetics , Epstein-Barr Virus Infections/complications , Epstein-Barr Virus Infections/diagnosis , Female , HIV Infections/complications , Herpesvirus 4, Human/isolation & purification , High-Throughput Nucleotide Sequencing , Humans , Male , Papillomavirus Infections/complications , Papillomavirus Infections/diagnosis
7.
AAPS PharmSciTech ; 19(3): 1454-1467, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29464594

ABSTRACT

Treatment of bacterial infections becomes increasingly complicated due to increasing bacterial resistance and difficulty in developing new antimicrobial agents. Emphasis should be laid on improvising the existing treatment modalities. We studied the improved antimicrobial and antibiofilm activity of levofloxacin (LFX) and lysozyme (LYS) in microbiological studies. LFX at sub-minimum inhibitory concentration with LYS eradicated > 85% of preformed biofilm. LFX was actively loaded into the liposomes using pH gradient method and was spray-dried with LYS solution. Percent entrapment of LFX in liposome was > 80% and prolonged cumulative release of 85% LFX at the end of 12 h. In vitro lung deposition study and solid-state characterization for spray dried LFX liposome in combination with LYS (LFX liposome-LYS) was performed. Co-spray dried product had mass median aerodynamic diameter ranging < 5 µm. In pharmacodynamic study, Staphylococcus aureus infected rats were treated with LFX liposome-LYS. Lungs, bronchoalveolar lavage fluid (BALF), and nasal fluid were evaluated for microbial burden. Expression of cytokine levels in BALF and serum were also studied by ELISA. In addition, mRNA expression for lung inflammatory mediators and lung myeloperoxidase activity were carried out. Further, lungs and histological changes were observed grossly. Untreated infected rat lungs demonstrated higher mRNA expression for inflammatory markers, cytokine levels, and microbial load compared to vehicle control. Conversely, LFX liposome-LYS significantly abated these adverse repercussions. Histology findings were also in agreement of above. Acute toxicity study revealed safeness of LFX liposome-LYS. Our findings confirm LFX liposome-LYS exhibited prolonged, improved antibiofilm and antimicrobial efficacy in treating S. aureus infection.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Biofilms/drug effects , Levofloxacin/therapeutic use , Lung Diseases/drug therapy , Muramidase/therapeutic use , Respiratory Tract Infections/drug therapy , Staphylococcal Infections/drug therapy , Administration, Inhalation , Animals , Anti-Bacterial Agents/administration & dosage , Drug Therapy, Combination , Levofloxacin/administration & dosage , Liposomes , Lung Diseases/metabolism , Lung Diseases/microbiology , Lung Diseases/pathology , Muramidase/administration & dosage , Rats , Respiratory Tract Infections/metabolism , Respiratory Tract Infections/microbiology , Respiratory Tract Infections/pathology , Staphylococcal Infections/metabolism , Staphylococcal Infections/microbiology , Staphylococcal Infections/pathology , Staphylococcus aureus
8.
J Biol Chem ; 291(7): 3496-507, 2016 Feb 12.
Article in English | MEDLINE | ID: mdl-26670606

ABSTRACT

Apoptosis is one of the mechanisms used by host cells to remove unwanted intracellular organisms, and often found to be subverted by pathogens through use of host anti-apoptotic proteins. In the present study, with the help of in vitro and in vivo approaches, we documented that the macrophage anti-apoptotic protein myeloid cell leukemia 1 (MCL-1) is exploited by the intra-macrophage parasite Leishmania donovani to protect their "home" from actinomycin D-induced mitochondria-dependent apoptosis. Among all the anti-apoptotic BCL-2 family members, infection preferentially up-regulated expression of MCL-1 at both the mRNA and protein levels and compared with infected control, MCL-1-silenced infected macrophages documented enhanced caspase activity and increased apoptosis when subjected to actinomycin D treatment. Phosphorylation kinetics and ChIP assay demonstrated that infection-induced MCL-1 expression was regulated by transcription factor CREB (cAMP-response element-binding protein) and silencing of CREB resulted in reduced expression of MCL-1 and increased apoptosis. During infection, MCL-1 was found to be localized in mitochondria and this was significantly reduced in Tom70-silenced macrophages, suggesting the active role of TOM70 in MCL-1 transport. In the mitochondria, MCL-1 interacts with the major pro-apoptotic protein BAK and prevents BAK-BAK homo-oligomer formation thereby preventing cytochrome c release-mediated mitochondrial dysfunction. Silencing of MCL-1 in the spleen of infected mice showed decreased parasite burden and increased induction of splenocyte apoptosis. Collectively our results showed that L. donovani exploited the macrophage anti-apoptotic protein MCL-1 to prevent BAK-mediated mitochondria-dependent apoptosis thereby protecting its niche, which is essential for disease progression.


Subject(s)
Antiparasitic Agents/pharmacology , Apoptosis/drug effects , Host-Parasite Interactions/drug effects , Leishmania donovani/drug effects , Leishmaniasis, Visceral/drug therapy , Macrophages/drug effects , Myeloid Cell Leukemia Sequence 1 Protein/metabolism , Animals , Antiparasitic Agents/therapeutic use , Bone Marrow Cells/drug effects , Bone Marrow Cells/metabolism , Bone Marrow Cells/parasitology , Bone Marrow Cells/pathology , Cells, Cultured , Cyclic AMP Response Element-Binding Protein/antagonists & inhibitors , Cyclic AMP Response Element-Binding Protein/genetics , Cyclic AMP Response Element-Binding Protein/metabolism , Dactinomycin/pharmacology , Dactinomycin/therapeutic use , Female , Gene Expression Regulation/drug effects , Leishmania donovani/growth & development , Leishmania donovani/physiology , Leishmaniasis, Visceral/metabolism , Leishmaniasis, Visceral/parasitology , Leishmaniasis, Visceral/pathology , Macrophages/metabolism , Macrophages/parasitology , Macrophages/pathology , Mice , Mice, Inbred BALB C , Myeloid Cell Leukemia Sequence 1 Protein/antagonists & inhibitors , Myeloid Cell Leukemia Sequence 1 Protein/genetics , Phosphorylation/drug effects , Protein Processing, Post-Translational/drug effects , Protein Transport/drug effects , RAW 264.7 Cells , RNA Interference , Spleen/drug effects , Spleen/metabolism , Spleen/parasitology , Spleen/pathology
9.
Biomacromolecules ; 18(11): 3630-3641, 2017 Nov 13.
Article in English | MEDLINE | ID: mdl-28879763

ABSTRACT

This study reports the self-assembly and application of a naphthalene diimide (NDI)-appended peptide amphiphile (PA). H-bonding among the peptide moiety in conjunction with π-stacking between NDI and hydrophobic interactions within the alkyl chain are the major driving forces behind the stepwise aggregation of the PA to form hydrogels. The PA produced efficient self-assemblies in water, forming a nanofibrous network that further formed a self-supportive hydrogel. The molecule followed a three-step self-assembly mechanism. At a lower concentration (50 µM), it forms extremely small aggregates with a very low population of the molecules. With an increase in concentration, spherical aggregates are formed above 450 µM concentration. Importantly, this water-soluble conjugate was found to be nontoxic, cell permeable, and usable for cell imaging. Moreover, the aggregation process and consequently the emission behavior are highly responsive to the pH of the medium. Thus, the pH responsive aggregation and emission behavior has an extended biological application for assessing intracellular pH. The biocompatibility and intracellular pH determining capability suggest it is a promising candidate for use as a supramolecular material in biomedical applications.


Subject(s)
Cell Tracking/methods , Hydrogels/chemistry , Imides/chemistry , Naphthalenes/chemistry , Peptides/chemistry , Biosensing Techniques , Cytoplasm/chemistry , Humans , Hydrogen Bonding , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Peptides/chemical synthesis , Water/chemistry
10.
Nanomedicine ; 13(7): 2371-2384, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28648640

ABSTRACT

Bacterial resistance remains a major hindrance in treatment with antimicrobial agents. Therefore, we assessed the improved antimicrobial and antibiofilm activity of Levofloxacin (LFX) and Serratiopeptidase (SRP) combinations in in vitro microbiological studies. Further, pharmacodynamic and pharmacokinetic studies of liposomal LFX in combination with SRP (LFX liposome-SRP) were performed in S. aureus infected rats. LFX at sub-MIC with SRP eradicated >90% of the preformed biofilm. The entrapment efficiency of LFX in liposome was >80% and the co-spray dried product had MMAD <5 µm. We observed high LFX concentration in the lung (3.39 µg/ml over 3 h) and AUC/MIC ≥100. In a pharmacodynamic study, untreated infected rat lungs demonstrated higher mRNA expression for inflammatory markers, cytokine levels and microbial load compared to control. Conversely, LFX liposome-SRP significantly abated these adverse repercussions. Histological findings were also in agreement with these observations. Furthermore, our findings corroborate exhibited improved antibiofilm and antimicrobial efficacy of LFX liposome-SRP in treating S. aureus infection.


Subject(s)
Anti-Bacterial Agents/administration & dosage , Levofloxacin/administration & dosage , Lung/microbiology , Peptide Hydrolases/administration & dosage , Staphylococcal Infections/drug therapy , Staphylococcus aureus/drug effects , Administration, Inhalation , Animals , Anti-Bacterial Agents/pharmacokinetics , Anti-Bacterial Agents/therapeutic use , Biofilms/drug effects , Drug Combinations , Drug Synergism , Female , Levofloxacin/pharmacokinetics , Levofloxacin/therapeutic use , Liposomes , Lung/pathology , Microbial Sensitivity Tests , Peptide Hydrolases/pharmacokinetics , Peptide Hydrolases/therapeutic use , Rats, Wistar , Staphylococcal Infections/pathology , Staphylococcus aureus/physiology
11.
J Biol Chem ; 289(2): 1092-105, 2014 Jan 10.
Article in English | MEDLINE | ID: mdl-24275663

ABSTRACT

One of the mechanisms for establishment of infection employed by intra-macrophage pathogen-like Leishmania is inhibition of oxidative burst-mediated macrophage apoptosis to protect their niche for survival and replication. We tried to elucidate the underlying mechanism for this by using H2O2 for induction of apoptosis. Leishmania donovani-infected macrophages were much more resistant to H2O2-mediated apoptosis compared with control. Although infected cells were capable of comparable reactive oxygen species production, there was less activation of the downstream cascade consisting of caspase-3 and -7 and cleaved poly(ADP)-ribose polymerase. Suppressors of cytokine signaling (SOCS) 1 and 3 proteins and reactive oxygen species scavenging enzyme thioredoxin, known to be involved in stabilization of protein-tyrosine phosphatases, were found to be induced during infection. Induction of SOCS proteins may be mediated by Egr1, and silencing of Socs1 and -3 either alone or in combination resulted in reduced thioredoxin levels, enhanced activation of caspases, and increased apoptosis of infected macrophages. The induction of protein-tyrosine phosphatases, thioredoxin, SOCS, and Egr1 in L. donovani-infected macrophages was found to be unaffected by H2O2 treatment. SOCS knocked down cells also displayed decreased parasite survival thus marking reduction in disease progression. Taken together, these results suggest that L. donovani may exploit SOCS for subverting macrophage apoptotic machinery toward establishing its replicative niche inside the host.


Subject(s)
Apoptosis/physiology , Leishmania donovani/growth & development , Macrophages/metabolism , Suppressor of Cytokine Signaling Proteins/metabolism , Animals , Apoptosis/drug effects , Caspases/metabolism , Cell Line , Early Growth Response Protein 1/metabolism , Gene Expression , Host-Pathogen Interactions , Hydrogen Peroxide/pharmacology , Immunoblotting , Leishmania donovani/physiology , Macrophages/microbiology , Mice , Mitogen-Activated Protein Kinases/metabolism , Oxidants/pharmacology , Phagocytosis/physiology , Protein Tyrosine Phosphatases/metabolism , RNA Interference , Respiratory Burst/physiology , Reverse Transcriptase Polymerase Chain Reaction , Suppressor of Cytokine Signaling 1 Protein , Suppressor of Cytokine Signaling 3 Protein , Suppressor of Cytokine Signaling Proteins/genetics , Thioredoxins/metabolism
12.
Antimicrob Agents Chemother ; 59(5): 2531-9, 2015 May.
Article in English | MEDLINE | ID: mdl-25691644

ABSTRACT

18ß-Glycyrrhetinic acid (GRA), a natural immunomodulator, greatly reduced the parasite load in experimental visceral leishmaniasis through nitric oxide (NO) upregulation, proinflammatory cytokine expression, and NF-κB activation. For the GRA-mediated effect, the primary kinase responsible was found to be p38, and analysis of phosphorylation kinetics as well as studies with dominant-negative (DN) constructs revealed mitogen-activated protein kinase kinase 3 (MKK3) and MKK6 as the immediate upstream regulators of p38. However, detection of remnant p38 kinase activity in the presence of both DN MKK3 and MKK6 suggested alternative pathways of p38 activation. That residual p38 activity was attributed to an autophosphorylation event ensured by the transforming growth factor ß-activated kinase 1 (TAK1)-binding protein 1 (TAB1)-p38 interaction and was completely abolished upon pretreatment with SB203580 in DN MKK3/6 double-transfected macrophage cells. Further upstream signaling evaluation by way of phosphorylation kinetics and transfection studies with DN constructs identified TAK1, myeloid differentiation factor 88 (MyD88), interleukin 1 receptor (IL-1R)-activated kinase 1 (IRAK1), and tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) as important contributors to GRA-mediated macrophage activation. Finally, gene knockdown studies revealed Toll-like receptor 2 (TLR2) and TLR4 as the membrane receptors associated with GRA-mediated antileishmanial activity. Together, the results of this study brought mechanistic insight into the antileishmanial activity of GRA, which is dependent on the TLR2/4-MyD88 signaling axis, leading to MKK3/6-mediated canonical and TAB1-mediated noncanonical p38 activation.


Subject(s)
Antiparasitic Agents/pharmacology , Glycyrrhetinic Acid/analogs & derivatives , Leishmania donovani/drug effects , Toll-Like Receptors/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism , Animals , Cell Line , Enzyme-Linked Immunosorbent Assay , Glycyrrhetinic Acid/pharmacology , Immunoblotting , Immunoprecipitation , Mice , Parasitic Sensitivity Tests , Toll-Like Receptors/genetics , p38 Mitogen-Activated Protein Kinases/genetics
13.
FASEB J ; 28(4): 1756-68, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24391131

ABSTRACT

Intramacrophage pathogen Leishmania donovani escapes host immune response by subverting Toll-like receptor (TLR) signaling, which is critically regulated by protein ubiquitination. In the present study, we identified tumor necrosis factor receptor-associated factor (TRAF) 3, degradative ubiquitination of which is essential for TLR4 activation, as a target for Leishmania to deactivate LPS-mediated TLR4 signaling. We used LPS-treated RAW 264.7 cells and compared the TLR4-mediated immune response in these cells with L. donovani and L. donovani + LPS costimulated macrophages. TRAF3, which was ubiquitinated (2.1-fold over control) at lys 48 position and subsequently degraded following LPS treatment, persisted in L. donovani and L. donovani + LPS costimulated cells due to defective lys 48 ubiquitination. Lys 63-linked ubiquitination of upstream proteins in the cascade (cIAP1/2 and TRAF6), mandatory for TRAF3 degradation, was also reduced postinfection. This may be attributed to reduced association between ubiquitin-conjugating enzyme Ubc13 and TRAF6 during infection. Inhibition of TRAF3 before infection by shRNA in Balb/c mice showed enhanced IL-12 and TNF-α (10.8- and 8.1-fold over infected control) and decreased spleen parasite burden (61.3% suppression, P<0.001), thereby marking reduction in disease progression. Our findings identified TRAF3 as a novel molecular regulator exploited by Leishmania for successful infection.


Subject(s)
Leishmania donovani/immunology , Macrophages/immunology , Signal Transduction/immunology , TNF Receptor-Associated Factor 3/immunology , Toll-Like Receptor 4/immunology , Animals , Cell Line , Cells, Cultured , Gene Expression/immunology , Host-Parasite Interactions/immunology , Immunoblotting , Interleukin-12/genetics , Interleukin-12/immunology , Interleukin-12/metabolism , Leishmania donovani/physiology , Leishmaniasis, Visceral/genetics , Leishmaniasis, Visceral/immunology , Leishmaniasis, Visceral/parasitology , Lipopolysaccharides/immunology , Lipopolysaccharides/pharmacology , Lysine/immunology , Lysine/metabolism , Macrophages/metabolism , Macrophages/parasitology , Mice , Mice, Inbred BALB C , Models, Immunological , NF-kappa B/genetics , NF-kappa B/immunology , NF-kappa B/metabolism , RNA Interference , Reverse Transcriptase Polymerase Chain Reaction , TNF Receptor-Associated Factor 3/genetics , TNF Receptor-Associated Factor 3/metabolism , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/immunology , Tumor Necrosis Factor-alpha/metabolism , Ubiquitination/drug effects , Ubiquitination/immunology
14.
Virology ; 597: 110143, 2024 Jun 18.
Article in English | MEDLINE | ID: mdl-38917692

ABSTRACT

Merkel Cell Carcinoma (MCC) is a rare neuroendocrine skin cancer. In our previous work, we decoded genes specifically deregulated by MCPyV early genes as opposed to other polyomaviruses and established functional importance of NDRG1 in inhibiting cellular proliferation and migration in MCC. In the present work, we found the SET protein, (I2PP2A, intrinsic inhibitor of PP2A) upstream of NDRG1 which was modulated by MCPyV early genes, both in hTERT-HK-MCPyV and MCPyV-positive (+) MCC cell lines. Additionally, MCC dermal tumour nodule tissues showed strong SET expression. Inhibition of the SET-PP2A interaction in hTERT-HK-MCPyV using the small molecule inhibitor, FTY720, increased NDRG1 expression and inhibited cell cycle regulators, cyclinD1 and CDK2. SET inhibition by shRNA and FTY720 also decreased cell proliferation and colony formation in MCPyV(+) MCC cells. Overall, these results pave a path for use of drugs targeting SET protein for the treatment of MCC.

15.
J Clin Invest ; 133(18)2023 09 15.
Article in English | MEDLINE | ID: mdl-37490341

ABSTRACT

Vascular networks form, remodel, and mature under the influence of both fluid shear stress (FSS) and soluble factors. Physiological FSS promotes and maintains vascular stability via synergy with bone morphogenic proteins 9 and 10 (BMP9 and BMP10). Conversely, mutation of the BMP receptors activin-like kinase 1 (ALK1), endoglin (ENG), or the downstream effector, SMAD family member 4 (SMAD4) leads to hereditary hemorrhagic telangiectasia (HHT), characterized by fragile and leaky arterial-venous malformations (AVMs). How endothelial cells (ECs) integrate FSS and BMP signals in vascular development and homeostasis and how mutations give rise to vascular malformations is not well understood. Here, we aimed to elucidate the mechanism of synergy between FSS and SMAD signaling in vascular stability and how disruption of this synergy leads to AVMs. We found that loss of Smad4 increased the sensitivity of ECs to flow by lowering the FSS set point, with resulting AVMs exhibiting features of excessive flow-mediated morphological responses. Mechanistically, loss of SMAD4 disinhibits flow-mediated KLF4-TIE2-PI3K/Akt signaling, leading to cell cycle progression-mediated loss of arterial identity due to KLF4-mediated repression of cyclin dependent Kinase (CDK) inhibitors CDKN2A and CDKN2B. Thus, AVMs caused by Smad4 deletion are characterized by chronic high flow remodeling with excessive EC proliferation and loss of arterial identity as triggering events.


Subject(s)
Arteriovenous Malformations , Telangiectasia, Hereditary Hemorrhagic , Mice , Animals , Arteriovenous Malformations/genetics , Arteriovenous Malformations/metabolism , Endothelial Cells/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Mice, Knockout , Telangiectasia, Hereditary Hemorrhagic/genetics , Bone Morphogenetic Proteins/genetics
16.
mSphere ; 8(6): e0045023, 2023 Dec 20.
Article in English | MEDLINE | ID: mdl-37877723

ABSTRACT

IMPORTANCE: Here, we demonstrate that the direct binding of p53 on the IL-18 promoter region regulates its gene expression. However, the presence of E6 and E7 from human papillomavirus type 38 impairs this mechanism via a new inhibitory complex formed by DNA methyltransferase 1 (DNMT1)/PKR/ΔNp73α, which binds to the region formerly occupied by p53 in primary keratinocytes.


Subject(s)
Cytokines , Tumor Suppressor Protein p53 , Humans , Cytokines/metabolism , Interleukin-18/genetics , Interleukin-18/metabolism , Papillomavirus E7 Proteins/genetics , Transcriptional Activation , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism
17.
Infect Agent Cancer ; 18(1): 71, 2023 Nov 08.
Article in English | MEDLINE | ID: mdl-37941001

ABSTRACT

BACKGROUND: Although the role of viral agents, such as human papillomavirus (e.g. HPV16, HPV18) in colorectal cancer (CRC) has been previously investigated, results remain inconclusive. METHODS: To further evaluate the involvement of oncogenic HPV types in CRC, 40 frozen neoplastic and 40 adjacent colonic tissues collected from Italian patients were analyzed by Luminex-based assays that detect a broad spectrum of HPV types, i.e. Alpha (n = 21), Beta (n = 46) and Gamma HPVs (n = 52). In addition, 125 frozen CRC samples and 70 surrounding mucosal tissues were collected from Czech patients and analyzed by broad spectrum PCR protocols: (i) FAP59/64, (ii) FAPM1 and (iii) CUT combined with Next Generation Sequencing (NGS). RESULTS: Using Luminex-basedassays, DNA from HPV16 was detected in 5% (2/40) CRC tissues from Italian patients. One HPV16 DNA-positive CRC case was subsequently confirmed positive for E6*I mRNA. Cutaneous beta HPV types were detected in 10% (4/40) adjacent tissues only, namely HPV111 (n = 3) and HPV120 (n = 1), while gamma HPV168 (n = 1) and HPV199 (n = 1) types were detected in adjacent and in tumor tissues, respectively. The NGS analysis of the CRC Czech samples identified HPV sequences from mucosal alpha-3 (HPV89), alpha-7 (HPV18, 39, 68 and 70) and alpha-10 species (HPV11), as well as cutaneous beta-1 (HPV20, 24, 93, 98, 105,124) beta-2 (HPV23), beta-3 (HPV49) and gamma-1 species (HPV205). CONCLUSIONS: Our findings indicate that HPV types belonging to the mucosal alpha, and the 'cutaneous' beta and gamma genera can be detected in the colonic mucosal samples with a low prevalence rate and a low number of HPV reads by Luminex and NGS, respectively. However, additional studies are required to corroborate these findings.

18.
J Infect ; 82(1): 112-116, 2021 01.
Article in English | MEDLINE | ID: mdl-33253726

ABSTRACT

BACKGROUND: To characterize the HPV diversity in the anal mucosa of men with different sexual behavior and HIV status by next-generation sequencing (NGS). METHODS: Anal swabs from HIV-positive (n = 94; mean age, 38 years) and HIV-negative (n = 100; mean age, 37.5 years) men who have sex with men (MSM) and HIV-negative men (predominantly men who have sex with women, MSW) (n = 99; mean age, 38.2 years) were analyzed by broad-spectrum PCR protocols combined with NGS. FINDINGS: Alpha HPV types (n = 74) were detected mainly in the MSM groups (HPV6, 11, and 43 were the most abundant types) compared with MSW (n = 16) (HPV11, 32, and 87 were among the most abundant). In contrast, beta HPVs were more abundantly detected among MSW (n = 45) than in the HIV-positive (n = 16) and HIV-negative (n = 26) MSM groups. Gamma HPVs were detected almost equally in HIV-positive MSM (n = 62), HIV-negative MSM (n = 58), and MSW (n = 57). In addition, 31 putative novel PV types were identified. CONCLUSIONS: Our data show that beta and gamma HPV types are present in the anal mucosa, thus reinforcing the existing evidence that they can be detected at anatomical sites other than skin. Alpha and beta HPV distribution among these three groups appears to vary according to sexual behavior.


Subject(s)
Alphapapillomavirus , HIV Infections , Papillomavirus Infections , Sexual and Gender Minorities , Adult , Anal Canal , Female , HIV Infections/complications , Homosexuality, Male , Humans , Male , Papillomaviridae/genetics , Papillomavirus Infections/complications , Papillomavirus Infections/epidemiology , Prevalence , Risk Factors
19.
Article in English | MEDLINE | ID: mdl-29737265

ABSTRACT

Nanotechnology has gained increased attention for delivering therapeutic agents effectively to the cardiovascular system. Heart targeted nanocarrier based drug delivery is a new, effective and efficacious approach for treating various cardiac related disorders such as atherosclerosis, hypertension, and myocardial infarction. Nanocarrier based drug delivery system circumvents the problems associated with conventional drug delivery systems, including their nonspecificity, severe side effects and damage to the normal cells. Modification of physicochemical properties of nanocarriers such as size, shape and surface modifications can immensely alter its invivo pharmacokinetic and pharmacodynamic data and will provide better treatment strategy. Several nanocarriers such as lipid, phospholipid nanoparticles have been developed for delivering drugs to the target sites within the heart. This review summarizes and increases the understanding of the advanced nanosized drug delivery systems for treating cardiovascular disorders with the promising use of nanotechnology.


Subject(s)
Cardiovascular Diseases/therapy , Drug Delivery Systems/methods , Nanomedicine/methods , Nanoparticles/therapeutic use , Cardiovascular Diseases/pathology , Humans
20.
Sci Rep ; 9(1): 3928, 2019 03 08.
Article in English | MEDLINE | ID: mdl-30850620

ABSTRACT

CRISPR-Cas9/gRNA exhibits therapeutic efficacy against latent human immunodeficiency virus (HIV) genome but the delivery of this therapeutic cargo to the brain remains as a challenge. In this research, for the first time, we demonstrated magnetically guided non-invasive delivery of a nano-formulation (NF), composed of Cas9/gRNA bound with magneto-electric nanoparticles (MENPs), across the blood-brain barrier (BBB) to inhibit latent HIV-1 infection in microglial (hµglia)/HIV (HC69) cells. An optimized ac-magnetic field of 60 Oe was applied on NF to release Cas9/gRNA from MENPs surface and to facilitate NF cell uptake resulting in intracellular release and inhibition of HIV. The outcomes suggested that developed NF reduced HIV-LTR expression significantly in comparison to unbound Cas9/gRNA in HIV latent hµglia/HIV (HC69) cells. These findings were also validated qualitatively using fluorescence microscopy to assess NF efficacy against latent HIV in the microglia cells. We believe that CNS delivery of NF (CRISPR/Cas9-gRNA-MENPs) across the BBB certainly will have clinical utility as future personalized nanomedicine to manage neuroHIV/AIDS.


Subject(s)
Blood-Brain Barrier/virology , HIV Infections/therapy , HIV Infections/virology , HIV-1 , RNA, Guide, Kinetoplastida/administration & dosage , CRISPR-Cas Systems , Cells, Cultured , Drug Delivery Systems , Gene Editing/methods , HIV-1/genetics , Humans , In Vitro Techniques , Magnetite Nanoparticles/administration & dosage , RNA, Guide, Kinetoplastida/genetics , Virus Latency
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