scholarly journals Increased host ATP efflux and its conversion to extracellular adenosine is crucial for establishing Leishmania infection

2020 ◽  
Vol 133 (7) ◽  
pp. jcs239939 ◽  
Author(s):  
Moumita Basu ◽  
Purnima Gupta ◽  
Ananya Dutta ◽  
Kuladip Jana ◽  
Anindita Ukil
Keyword(s):  
Leishmania Infection ◽  
Extracellular Adenosine ◽  
Atp Efflux

scholarly journals ATP release through pannexon channels

2015 ◽  
Vol 370 (1672) ◽  
pp. 20140191 ◽  
Author(s):  
Gerhard Dahl
Keyword(s):  
Purinergic Receptors ◽  
Control Mechanism ◽  
Atp Release ◽  
Extracellular Adenosine ◽  
Large Channel ◽  
Selective Channel ◽  
And Control ◽  
Atp Efflux ◽  
Excessive Activation ◽  
Voltage Activation

Extracellular adenosine triphosphate (ATP) serves as a signal for diverse physiological functions, including spread of calcium waves between astrocytes, control of vascular oxygen supply and control of ciliary beat in the airways. ATP can be released from cells by various mechanisms. This review focuses on channel-mediated ATP release and its main enabler, Pannexin1 (Panx1). Six subunits of Panx1 form a plasma membrane channel termed ‘pannexon’. Depending on the mode of stimulation, the pannexon has large conductance (500 pS) and unselective permeability to molecules less than 1.5 kD or is a small (50 pS), chloride-selective channel. Most physiological and pathological stimuli induce the large channel conformation, whereas the small conformation so far has only been observed with exclusive voltage activation of the channel. The interaction between pannexons and ATP is intimate. The pannexon is not only the conduit for ATP, permitting ATP efflux from cells down its concentration gradient, but the pannexon is also modulated by ATP. The channel can be activated by ATP through both ionotropic P2X as well as metabotropic P2Y purinergic receptors. In the absence of a control mechanism, this positive feedback loop would lead to cell death owing to the linkage of purinergic receptors with apoptotic processes. A control mechanism preventing excessive activation of the purinergic receptors is provided by ATP binding (with low affinity) to the Panx1 protein and gating the channel shut.

DETECTION OF LEISHMANIA INFECTION IN STRAY DOGS IN HUMAN LEISHMANIASIS ENDEMIC AREA IN MYMENSINGH DISTRICT WITH ITS POSSIBLE PUBLIC HEALTH SIGNIFICANCE IN BANGLADESH

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
M. A. Hossen
Keyword(s):  
Visceral Leishmaniasis ◽  
Asymptomatic Carrier ◽  
Asymptomatic Infection ◽  
Reservoir Host ◽  
Sand Fly ◽  
Leishmania Infection ◽  
Endemic Region ◽  
Stray Dogs ◽  
Human Leishmaniasis ◽  
Strip Test

Background: Leishmaniasis is primarily caused by two species of Leishmania (L. donovani and L. infantum) of which clinical infection with L. infantum has been recognized in both humans and dogs as zoonotic disease with dogs as the main reservoir hosts in the Mediterranean, the Middle East, Asia and South America. Although L. donovani has been associated with both clinical and asymptomatic infection in humans but it is still associated with asymptomatic infection in dogs in Indian sub-continent without any evidence of zoonotic infection. Objectives: The objective of this research was to investigate the potentiality of dog as reservoir host for visceral leishmaniasis in the human leishmaniasis endemic regions in Bangladesh. Materials and Methods: A total of 20 stray dogs in the human VL endemic areas of Mymensingh district were captured for the detection VL during the period of November 2010 to May 2011. The dipstick test rK39 (Bios International; n = 20), Giemsa’s stained impression smears of liver and spleen (n = 6) and PCR with the tissue of liver and spleen (n = 6) were tested as per manufacturer instructions and conventional standard methods. Results: Out of 20 stray dogs examined, 4 (20.0%) were positive for L. donovani infection with rK39 strip test. Of the six randomly selected dogs tested with Modified Giemsa’s stained of impression smears of spleen and liver showed 2 (33.33%) positive whereas PCR technique detected 5 (83.33%) positive for L. donovani. Results of PCR showed 145bp amplicon, specific for L. donovani infection in 83.33% stray dogs. Conclusions: This study reveals that a high percentage of L. donovani asymptomatic carrier infections occur in dogs and evidence indicates that dogs and humans may potentially serve as a source of infection to sand fly vectors and accordingly dogs can be recognized as a probable animal reservoir for the Leishmania infection in the endemic region in Bangladesh. However, further studies are required to determine the ability of dogs to transmit the L. donovani to the vector sand fly in nature and its evidence on ‘One Health’ perspectives. Keywords: Visceral leishmaniasis, Endemic region, Stray dogs, rK39 strip test, Giemsa’s stained liver and spleen impression smears, PCR, Reservoir host, Mymensingh

Use of enzyme somase® in the measurement of biofilm using bioluminescence

1995 ◽  
Vol 32 (8) ◽  
pp. 221-225 ◽  
Author(s):  
M. Greetham ◽  
B. Holden ◽  
J. Scutt
Keyword(s):  
Distribution System ◽  
System Model ◽  
Extracellular Adenosine ◽  
To Come

Analysis of the biofilm on a distribution system model pipe rig gave high readings of extracellular adenosine-5′-triphosphate (ATP). The free ATP was assumed to come from dead cells at the base of the biofilm. The levels were large in proportion to the measured cellular ATP and were unstable. This resulted in errors in the calculation of cellular ATP. An enzyme Somase (0.5%) was employed to hydrolyse the free ATP. Increased accuracy of the measurement of cellular ATP was seen.

PET Imaging of Adenosine Receptors in Diseases

2019 ◽  
Vol 19 (16) ◽  
pp. 1445-1463 ◽  
Author(s):  
Jindian Li ◽  
Xingfang Hong ◽  
Guoquan Li ◽  
Peter S. Conti ◽  
Xianzhong Zhang ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Adenosine Receptors ◽  
Neurological Diseases ◽  
G Protein Coupled Receptors ◽  
Extracellular Adenosine ◽  
Positron Emission ◽  
Imaging Probes ◽  
Pet Probes ◽  
Cancer And Inflammation ◽  
G Protein Coupled

Adenosine receptors (ARs) are a class of purinergic G-protein-coupled receptors (GPCRs). Extracellular adenosine is a pivotal regulation molecule that adjusts physiological function through the interaction with four ARs: A1R, A2AR, A2BR, and A3R. Alterations of ARs function and expression have been studied in neurological diseases (epilepsy, Alzheimer’s disease, and Parkinson’s disease), cardiovascular diseases, cancer, and inflammation and autoimmune diseases. A series of Positron Emission Tomography (PET) probes for imaging ARs have been developed. The PET imaging probes have provided valuable information for diagnosis and therapy of diseases related to alterations of ARs expression. This review presents a concise overview of various ARs-targeted radioligands for PET imaging in diseases. The most recent advances in PET imaging studies by using ARs-targeted probes are briefly summarized.

scholarly journals Isolation and Molecular Typing of Leishmania infantum from Phlebotomus perfiliewi in a Re-Emerging Focus of Leishmaniasis, Northeastern Italy

2019 ◽  
Vol 7 (12) ◽  
pp. 644
Author(s):  
Mattia Calzolari ◽  
Elena Carra ◽  
Gianluca Rugna ◽  
Paolo Bonilauri ◽  
Federica Bergamini ◽  
...  
Keyword(s):  
Leishmania Infection ◽  
Sand Flies ◽  
Repetitive Region ◽  
Microsatellite Typing ◽  
Increasing Trend ◽  
Northeastern Italy ◽  
Emilia Romagna Region ◽  
Phlebotomus Perfiliewi ◽  
Leishmania Parasites

Visceral leishmaniasis (VL) caused by Leishmania (L.) infantum is a public health threat in the Emilia-Romagna region, northeastern Italy, but its epidemiology has not been fully elucidated in this area. The objective of this study was to characterize Leishmania infection in sand flies collected in a re-emerging focus of VL in the Bologna province. During the summer of 2016, 6114 sand flies were collected, identified, and tested for Leishmania detection. Of the identified sand flies, 96.5% were Phlebotomus (P.) perfiliewi and 3.5% were P. perniciosus. Detected parasites were characterized by biomolecular methods (multilocus microsatellite typing and characterization of repetitive region on chromosome 31), and quantified by real-time PCR. The prevalence of Leishmania infection in individually-tested P. perfiliewi sand flies varied from 6% to 10% with an increasing trend during the season. Promastigotes of L. infantum were isolated by dissection in one P. perfiliewi female; the isolated strain (Lein-pw) were closely related to Leishmania parasites from VL cases in northeastern Italy, but differed from strains isolated in dogs from the same area. Our findings strongly support the vector status of P. perfiliewi for human VL in the study area.

scholarly journals Structure of the full-length human Pannexin1 channel and insights into its role in pyroptosis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Sensen Zhang ◽  
Baolei Yuan ◽  
Jordy Homing Lam ◽  
Jun Zhou ◽  
Xuan Zhou ◽  
...  
Keyword(s):  
Md Simulation ◽  
Potential Role ◽  
Md Simulations ◽  
Full Length ◽  
Inflammasome Activation ◽  
Simulation Studies ◽  
Cryo Electron Microscopy ◽  
Gating Mechanism ◽  
Atp Efflux

AbstractPannexin1 (PANX1) is a large-pore ATP efflux channel with a broad distribution, which allows the exchange of molecules and ions smaller than 1 kDa between the cytoplasm and extracellular space. In this study, we show that in human macrophages PANX1 expression is upregulated by diverse stimuli that promote pyroptosis, which is reminiscent of the previously reported lipopolysaccharide-induced upregulation of PANX1 during inflammasome activation. To further elucidate the function of PANX1, we propose the full-length human Pannexin1 (hPANX1) model through cryo-electron microscopy (cryo-EM) and molecular dynamics (MD) simulation studies, establishing hPANX1 as a homo-heptamer and revealing that both the N-termini and C-termini protrude deeply into the channel pore funnel. MD simulations also elucidate key energetic features governing the channel that lay a foundation to understand the channel gating mechanism. Structural analyses, functional characterizations, and computational studies support the current hPANX1-MD model, suggesting the potential role of hPANX1 in pyroptosis during immune responses.

scholarly journals Role of Circulating Immune Complexes in the Pathogenesis of Canine Leishmaniasis: New Players in Vaccine Development

2021 ◽  
Vol 9 (4) ◽  
pp. 712
Author(s):  
Cristina Cacheiro-Llaguno ◽  
Nuria Parody ◽  
Marta R. Escutia ◽  
Jerónimo Carnés
Keyword(s):  
Immune Complexes ◽  
Vaccine Development ◽  
Correct Diagnosis ◽  
Circulating Immune Complexes ◽  
Response To Treatment ◽  
Canine Leishmaniasis ◽  
Leishmania Infection ◽  
Serum Samples ◽  
Humoral Immune

During canine visceral leishmaniasis (CanL), due to Leishmania infantum (L. infantum), uncontrolled infection leads to a strong humoral immune response. As a consequence of the production of high antibody levels and the prolonged presence of parasite antigens, circulating immune complexes (CIC) are formed, which can be deposited in certain organs and tissues, inducing vasculitis, uveitis, dermatitis and especially glomerulonephritis and renal failure. A method to detect CIC and quantify their levels in serum samples from dogs infected with L. infantum has been recently described. It allowed demonstration of a correlation between CIC levels and disease severity. Thus, CIC measurement may be useful for diagnosis, assessment of disease progression and monitoring response to treatment. This is an interesting finding, considering that there remains an urgent need for identification of novel biomarkers to achieve a correct diagnosis and for optimal disease staging of dogs suffering from Leishmania infection. The objective of the present review is to shed light on the role of CIC in CanL, as well as to highlight their potential use not only as diagnostic and prognostic biomarkers but also as a valuable tool in vaccine development and new immunotherapy strategies to prevent or control disease outcome.

scholarly journals Mutagenic Analysis of the Putative ABCC6 Substrate-Binding Cavity Using a New Homology Model

2021 ◽  
Vol 22 (13) ◽  
pp. 6910
Author(s):  
Flora Szeri ◽  
Valentina Corradi ◽  
Fatemeh Niaziorimi ◽  
Sylvia Donnelly ◽  
Gwenaëlle Conseil ◽  
...  
Keyword(s):  
Binding Site ◽  
Efflux Pump ◽  
Substrate Binding ◽  
Functional Characterization ◽  
Atp Release ◽  
Homology Model ◽  
Atp Binding ◽  
Atp Binding Site ◽  
Binding Cavity ◽  
Atp Efflux

Inactivating mutations in ABCC6 underlie the rare hereditary mineralization disorder pseudoxanthoma elasticum. ABCC6 is an ATP-binding cassette (ABC) integral membrane protein that mediates the release of ATP from hepatocytes into the bloodstream. The released ATP is extracellularly converted into pyrophosphate, a key mineralization inhibitor. Although ABCC6 is firmly linked to cellular ATP release, the molecular details of ABCC6-mediated ATP release remain elusive. Most of the currently available data support the hypothesis that ABCC6 is an ATP-dependent ATP efflux pump, an un-precedented function for an ABC transporter. This hypothesis implies the presence of an ATP-binding site in the substrate-binding cavity of ABCC6. We performed an extensive mutagenesis study using a new homology model based on recently published structures of its close homolog, bovine Abcc1, to characterize the substrate-binding cavity of ABCC6. Leukotriene C4 (LTC4), is a high-affinity substrate of ABCC1. We mutagenized fourteen amino acid residues in the rat ortholog of ABCC6, rAbcc6, that corresponded to the residues in ABCC1 found in the LTC4 binding cavity. Our functional characterization revealed that most of the amino acids in rAbcc6 corresponding to those found in the LTC4 binding pocket in bovine Abcc1 are not critical for ATP efflux. We conclude that the putative ATP binding site in the substrate-binding cavity of ABCC6/rAbcc6 is distinct from the bovine Abcc1 LTC4-binding site.

Sign in / Sign up

Export Citation Format

Share Document