scholarly journals PET Imaging Radiotracers of Chemokine Receptors

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5174
Author(s):  
Santosh R. Alluri ◽  
Yusuke Higashi ◽  
Kun-Eek Kil
Keyword(s):  
Small Molecules ◽  
Chemokine Receptors ◽  
Brain Disorders ◽  
Infectious Agents ◽  
Cardiovascular Research ◽  
Critical Signal ◽  
Inflammatory Reactions ◽  
Positron Emission

Chemokines and chemokine receptors have been recognized as critical signal components that maintain the physiological functions of various cells, particularly the immune cells. The signals of chemokines/chemokine receptors guide various leukocytes to respond to inflammatory reactions and infectious agents. Many chemokine receptors play supportive roles in the differentiation, proliferation, angiogenesis, and metastasis of diverse tumor cells. In addition, the signaling functions of a few chemokine receptors are associated with cardiac, pulmonary, and brain disorders. Over the years, numerous promising molecules ranging from small molecules to short peptides and antibodies have been developed to study the role of chemokine receptors in healthy states and diseased states. These drug-like candidates are in turn exploited as radiolabeled probes for the imaging of chemokine receptors using noninvasive in vivo imaging, such as positron emission tomography (PET). Recent advances in the development of radiotracers for various chemokine receptors, particularly of CXCR4, CCR2, and CCR5, shed new light on chemokine-related cancer and cardiovascular research and the subsequent drug development. Here, we present the recent progress in PET radiotracer development for imaging of various chemokine receptors.

scholarly journals News about the Role of Fluid and Imaging Biomarkers in Neurodegenerative Diseases

Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 252
Author(s):  
Jacopo Meldolesi
Keyword(s):  
Neurodegenerative Diseases ◽  
Imaging Techniques ◽  
Imaging Biomarkers ◽  
Positron Emission ◽  
Specific Proteins ◽  
Great Relevance ◽  
The Brain ◽  
Positive Point

Biomarkers are molecules that are variable in their origin, nature, and mechanism of action; they are of great relevance in biology and also in medicine because of their specific connection with a single or several diseases. Biomarkers are of two types, which in some cases are operative with each other. Fluid biomarkers, started around 2000, are generated in fluid from specific proteins/peptides and miRNAs accumulated within two extracellular fluids, either the central spinal fluid or blood plasma. The switch of these proteins/peptides and miRNAs, from free to segregated within extracellular vesicles, has induced certain advantages including higher levels within fluids and lower operative expenses. Imaging biomarkers, started around 2004, are identified in vivo upon their binding by radiolabeled molecules subsequently revealed in the brain by positron emission tomography and/or other imaging techniques. A positive point for the latter approach is the quantitation of results, but expenses are much higher. At present, both types of biomarker are being extensively employed to study Alzheimer’s and other neurodegenerative diseases, investigated from the presymptomatic to mature stages. In conclusion, biomarkers have revolutionized scientific and medical research and practice. Diagnosis, which is often inadequate when based on medical criteria only, has been recently improved by the multiplicity and specificity of biomarkers. Analogous results have been obtained for prognosis. In contrast, improvement of therapy has been limited or fully absent, especially for Alzheimer’s in which progress has been inadequate. An urgent need at hand is therefore the progress of a new drug trial design together with patient management in clinical practice.

scholarly journals Molecular Basis for CCRL2 Regulation of Leukocyte Migration

2020 ◽  
Vol 8 ◽  
Author(s):  
Tiziana Schioppa ◽  
Francesca Sozio ◽  
Ilaria Barbazza ◽  
Sara Scutera ◽  
Daniela Bosisio ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Chemokine Receptors ◽  
Transmembrane Domain ◽  
Nk Cell ◽  
Structural Features ◽  
Negative Regulator ◽  
Leukocyte Migration ◽  
Genetic Ablation

CCRL2 is a seven-transmembrane domain receptor that belongs to the chemokine receptor family. At difference from other members of this family, CCRL2 does not promote chemotaxis and shares structural features with atypical chemokine receptors (ACKRs). However, CCRL2 also differs from ACKRs since it does not bind chemokines and is devoid of scavenging functions. The only commonly recognized CCRL2 ligand is chemerin, a non-chemokine chemotactic protein. CCRL2 is expressed both by leukocytes and non-hematopoietic cells. The genetic ablation of CCRL2 has been instrumental to elucidate the role of this receptor as positive or negative regulator of inflammation. CCRL2 modulates leukocyte migration by two main mechanisms. First, when CCRL2 is expressed by barrier cells, such endothelial, and epithelial cells, it acts as a presenting molecule, contributing to the formation of a non-soluble chemotactic gradient for leukocytes expressing CMKLR1, the functional chemerin receptor. This mechanism was shown to be crucial in the induction of NK cell-dependent immune surveillance in lung cancer progression and metastasis. Second, by forming heterocomplexes with other chemokine receptors. For instance, CCRL2/CXCR2 heterodimers were shown to regulate the activation of β2-integrins in mouse neutrophils. This mini-review summarizes the current understanding of CCRL2 biology, based on experimental evidence obtained by the genetic deletion of this receptor in in vivo experimental models. Further studies are required to highlight the complex functional role of CCRL2 in different organs and pathological conditions.

Multinucleated rat alveolar macrophages express functional receptors for calcitonin

1991 ◽  
Vol 261 (6) ◽  
pp. F1026-F1032 ◽  
Author(s):  
A. Vignery ◽  
M. J. Raymond ◽  
H. Y. Qian ◽  
F. Wang ◽  
S. A. Rosenzweig
Keyword(s):  
Plasma Membrane ◽  
Alveolar Macrophages ◽  
Giant Cells ◽  
Mononuclear Phagocytes ◽  
Inflammatory Reactions ◽  
Calcitonin Gene ◽  
Novel Model

The fusion of mononuclear phagocytes occurs spontaneously in vivo and leads to the differentiation of either multinucleated giant cells or osteoclasts in chronic inflammatory sites or in bone, respectively. Although osteoclasts are responsible for resorbing bone, the functional role of giant cells in chronic inflammatory reactions and tumors remains poorly understood. We recently reported that the plasma membrane of multinucleated macrophages is, like that of osteoclasts, enriched in Na-K-adenosinetriphosphatases (ATPases). We also observed that the localization of their Na-K-ATPases is restricted to the nonadherent domain of the plasma membrane of cells both in vivo and in vitro, thus imposing a functional polarity on their organization. By following this observation, we wished to investigate whether these cells also expressed, like osteoclasts, functional receptors for calcitonin (CT). To this end, alveolar macrophages were fused in vitro, and both their structural and functional association with CT was analyzed and compared with those of mononucleated peritoneal and alveolar macrophages. Evidence is presented that multinucleated alveolar macrophages express a high copy number of functional receptors for CT. Our results also indicate that alveolar macrophages, much like peritoneal, express functional receptors for calcitonin gene-related peptide. It is suggested that multinucleated rat alveolar macrophages offer a novel model system to study CT receptors and that calcitonin may control local immune reactions where giant cells differentiate.

scholarly journals Identification of a Subset of Human Immunodeficiency Virus Type 1 (HIV-1), HIV-2, and Simian Immunodeficiency Virus Strains Able To Exploit an Alternative Coreceptor on Untransformed Human Brain and Lymphoid Cells

2003 ◽  
Vol 77 (11) ◽  
pp. 6138-6152 ◽  
Author(s):  
Samantha J. Willey ◽  
Jacqueline D. Reeves ◽  
Richard Hudson ◽  
Koichi Miyake ◽  
Nathalie Dejucq ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Simian Immunodeficiency Virus ◽  
Cell Lines ◽  
Chemokine Receptors ◽  
Adult Brain ◽  
Immunodeficiency Virus ◽  
Siv Infection

ABSTRACT The chemokine receptors CCR5 and CXCR4 are the major coreceptors for human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV). At least 12 other chemokine receptors or close relatives support infection by particular HIV and SIV strains on CD4+ transformed indicator cell lines in vitro. However, the role of these alternative coreceptors in vivo is presently thought to be insignificant. Infection of cell lines expressing high levels of recombinant CD4 and coreceptors thus does not provide a true indication of coreceptor use in vivo. We therefore tested primary untransformed cell cultures that lack CCR5 and CXCR4, including astrocytes and brain microvascular endothelial cells (BMVECs), for naturally expressed alternative coreceptors functional for HIV and SIV infection. An adenovirus vector (Ad-CD4) was used to express CD4 in CD4− astrocytes and thus confer efficient infection if a functional coreceptor is present. Using a large panel of viruses with well-defined coreceptor usage, we identified a subset of HIV and SIV strains able to infect two astrocyte cultures derived from adult brain tissue. Astrocyte infection was partially inhibited by several chemokines, indicating a role for the chemokine receptor family in the observed infection. BMVECs were weakly positive for CD4 but negative for CCR5 and CXCR4 and were susceptible to infection by the same subset of isolates that infected astrocytes. BMVEC infection was efficiently inhibited by the chemokine vMIP-I, implicating one of its receptors as an alternative coreceptor for HIV and SIV infection. Furthermore, we tested whether the HIV type 1 and type 2 strains identified were able to infect peripheral blood mononuclear cells (PBMCs) via an alternative coreceptor. Several strains replicated in Δ32/Δ32 CCR5 PBMCs with CXCR4 blocked by AMD3100. This AMD3100-resistant replication was also sensitive to vMIP-I inhibition. The nature and potential role of this alternative coreceptor(s) in HIV infection in vivo is discussed.

Schistosoma mansoni: larval damage and role of effector cell(s) in the synergy between vaccine immunity and Praziquantel treatment

Parasitology ◽  
1991 ◽  
Vol 103 (2) ◽  
pp. 207-224 ◽  
Author(s):  
K. P. Piper ◽  
R. F. Mott ◽  
D. J. Hockley ◽  
D. J. McLaren
Keyword(s):  
Effector Cell ◽  
Inflammatory Reactions ◽  
Effector Cells ◽  
Ultrastructural Studies ◽  
Praziquantel Treatment ◽  
Internal Disruption ◽  
Lung Worms ◽  
Extent Of Damage

A number of authors have demonstrated that the schistosomicidal compound, Praziquantel (Pzq), depends for its action upon the immune status of the host (Sabah et al. 1985; Brindley & Sher, 1987; Doenhoff et al. 1987). We have attempted to define the synergistic interaction between immuno- and chemotherapy further, using the murine irradiated vaccine model of schistosomiasis mansoni. In vaccinated mice, resistance operates in the skin but not the lungs; drug targeted towards lung-stage worms exacerbates lung-phase immunity, however, as depicted by the increased number and size of inflammatory reactions in the pulmonary tissues. Parasites are often found trapped within such foci. In the present investigation, light and ultrastructural studies have been utilized to examine the nature and extent of damage inflicted upon lung-stage larvae recovered from day 6 Pzq-treated vaccinated mice. Such studies have revealed that damage involves muscle disorganization, internal disruption and occasionally, loss of the tegument; in the latter case, cells are often seen attached to the denuded lung worms. To identify the crucial cellular effector cell(s) involved in the synergy between immuno- and chemotherapy, cell depletion studies have been performed in vivo. It would appear from these experiments that eosinophils or lymphocytes rather than neutrophils or macrophages are important effector cells in this synergy. Histological studies argue in favour of eosinophils being the key effector cells.

scholarly journals Validation and noninvasive kinetic modeling of [11C]UCB-J PET imaging in mice

2019 ◽  
Vol 40 (6) ◽  
pp. 1351-1362 ◽  
Author(s):  
Daniele Bertoglio ◽  
Jeroen Verhaeghe ◽  
Alan Miranda ◽  
Istvan Kertesz ◽  
Klaudia Cybulska ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Neurodegenerative Disorder ◽  
Input Function ◽  
Dependent Manner ◽  
In Vivo Metabolism ◽  
Promising Tool ◽  
Positron Emission ◽  
Synaptic Pathology

Synaptic pathology is associated with several brain disorders, thus positron emission tomography (PET) imaging of synaptic vesicle glycoprotein 2A (SV2A) using the radioligand [11C]UCB-J may provide a tool to measure synaptic alterations. Given the pivotal role of mouse models in understanding neuropsychiatric and neurodegenerative disorders, this study aims to validate and characterize [11C]UCB-J in mice. We performed a blocking study to verify the specificity of the radiotracer to SV2A, examined kinetic models using an image-derived input function (IDIF) for quantification of the radiotracer, and investigated the in vivo metabolism. Regional TACs during baseline showed rapid uptake of [11C]UCB-J into the brain. Pretreatment with levetiracetam confirmed target engagement in a dose-dependent manner. VT (IDIF) values estimated with one- and two-tissue compartmental models (1TCM and 2TCM) were highly comparable (r=0.999, p < 0.0001), with 1TCM performing better than 2TCM for K1 (IDIF). A scan duration of 60 min was sufficient for reliable VT (IDIF) and K1 (IDIF) estimations. In vivo metabolism of [11C]UCB-J was relatively rapid, with a parent fraction of 22.5 ± 4.2% at 15 min p.i. In conclusion, our findings show that [11C]UCB-J selectively binds to SV2A with optimal kinetics in the mouse representing a promising tool to noninvasively quantify synaptic density in comparative or therapeutic studies in neuropsychiatric and neurodegenerative disorder models.

scholarly journals Bioanalysis and pharmacokinetic studies

2020 ◽  
pp. IPK01
Author(s):  
Maria Veneziano
Keyword(s):  
Drug Discovery ◽  
Small Molecules ◽  
Bioanalytical Methods ◽  
High Resolution Mass Spectrometry ◽  
Drug Candidate ◽  
Pharmacokinetic Studies ◽  
Inborn Errors ◽  
Drug Discovery Program

Biography: Maria Veneziano is currently a Research Investigator in the DMPK unit at IRBM (Pomezia, Italy), an Italian CRO and biotech company specializing in preclinical drug discovery of small molecules, peptides and antibodies. She studied Biological Science at ‘Federico II’ University of Naples (Italy) and completed her PhD in Medical Biotechnologies at Merck Research Laboratories (MRL) in Rome (Italy) developing bioanalytical methods used to identify and quantify amino acids and acylcarnitines for the diagnosis and follow-up of inborn errors of metabolism. As part of the DMPK team at MRL, she was involved in PK and ADME profiling of small molecule and peptide candidates for drug-discovery programs. Presently, Maria leads a group supporting PK and PK/PD studies for small molecules and peptides. Maria Veneziano speaks to the International Journal of Pharmacokinetics about her experience working on pharmacokinetic studies. She starts by discussing the conventional bioanalytical methods used for the quantitative analysis of small molecules and peptides and she highlights the important role of LC–MS detection and sample preparation in the bioanalysis of pharmacokinetic studies. She also speaks about the role of high-resolution mass spectrometry in the bioanalysis of peptides as an important tool in a drug-discovery program to simultaneously define pharmacokinetic and metabolic profiles of the same drug candidate. She also describes cassette dosing and cassette analysis approaches as strategies to increase sample throughput, highlighting advantages and limits of each of these strategies. Finally, Maria speaks about her idea of ‘simplified PK workflow’ based on the miniaturization and automation of all the steps in a PK study, from in vivo administration to sample analysis.

Double Lumen Needle in Unipuncture Dialysis Type Double Headpump

1981 ◽  
Vol 4 (2) ◽  
pp. 72-74 ◽  
Author(s):  
R. Vanholder ◽  
M. De Paepe ◽  
N.A. Hoenich ◽  
S. Ringoir ◽  
A. De Cubber ◽  
...  
Keyword(s):  
Small Molecules ◽  
Vascular Access ◽  
In Vitro Studies ◽  
Double Lumen ◽  
Single Lumen

Single needle dialysis is used as a method of vascular access in many European dialysis centres. However, recirculation has been incriminated as a disadvantage of this procedure. According to in vitro studies, recirculation should be limited to a minimum when using double lumen needles. The present study makes an in vivo comparison between single and double lumen needles in unipuncture (single needle) dialysis of the type double headpump (Bellco, BL 760) and studies the role of recirculation in dialysis performance. Although recirculation is significantly reduced with the double lumen needle, compared to the single lumen needle, the clearance of small molecules is not significantly different for both needle types.

scholarly journals Non-invasive imaging of high-risk coronary plaque: the role of computed tomography and positron emission tomography

2020 ◽  
Vol 93 (1113) ◽  
pp. 20190740 ◽  
Author(s):  
Rong Bing ◽  
Krithika Loganath ◽  
Philip Adamson ◽  
David Newby ◽  
Alastair Moss
Keyword(s):  
Positron Emission Tomography ◽  
Molecular Imaging ◽  
Coronary Plaque ◽  
Emission Tomography ◽  
Plaque Morphology ◽  
Biological Processes ◽  
Non Invasive ◽  
Positron Emission

Despite recent advances, cardiovascular disease remains the leading cause of death globally. As such, there is a need to optimise our current diagnostic and risk stratification pathways in order to better deliver individualised preventative therapies. Non-invasive imaging of coronary artery plaque can interrogate multiple aspects of coronary atherosclerotic disease, including plaque morphology, anatomy and flow. More recently, disease activity is being assessed to provide mechanistic insights into in vivo atherosclerosis biology. Molecular imaging using positron emission tomography is unique in this field, with the potential to identify specific biological processes using either bespoke or re-purposed radiotracers. This review provides an overview of non-invasive vulnerable plaque detection and molecular imaging of coronary atherosclerosis.

scholarly journals Recent insights into the role of the contact pathway in thrombo-inflammatory disorders

Hematology ◽  
2014 ◽  
Vol 2014 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Maurits L. van Montfoort ◽  
Joost C.M. Meijers
Keyword(s):  
Molecular Weight ◽  
Small Molecules ◽  
Antisense Oligonucleotides ◽  
Contact System ◽  
Factor Xii ◽  
High Molecular Weight Kininogen ◽  
Vascular Beds ◽  
Contact Pathway

Abstract The contact pathway of coagulation consists of the proteins factor XI, factor XII, prekallikrein, and high-molecular-weight kininogen. Activation of the contact system leads to procoagulant and proinflammatory reactions. The contact system is essential for surface-initiated coagulation, as exemplified by aPTT, but there is probably no role for the contact system in initiating physiologic in vivo coagulation. However, over the last few years, there has been renewed interest, especially because of experimental evidence suggesting that the contact system contributes to thrombosis. Knockout mice deficient in one of the contact proteins were protected against artificially induced thrombosis. Furthermore, inhibiting agents such as monoclonal antibodies, antisense oligonucleotides, and small molecules were found to prevent thrombosis in rodents and primates in both venous and arterial vascular beds. Although it remains to be established whether targeting the contact system will be effective in humans and which of the contact factors is the best target for anticoagulation, it would constitute a promising approach for future effective and safe antithrombotic therapy.

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