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Kumar K, Sihag B, Patil MT, Singh R, Sakala IG, Honda-Okubo Y, Singh KN, Petrovsky N, Salunke DB. Design and Synthesis of Polyphenolic Imidazo[4,5- c]quinoline Derivatives to Modulate Toll Like Receptor-7 Agonistic Activity and Adjuvanticity. ACS Pharmacol Transl Sci 2024; 7:2063-2079. [PMID: 39022355 PMCID: PMC11249636 DOI: 10.1021/acsptsci.4c00163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/16/2024] [Accepted: 05/28/2024] [Indexed: 07/20/2024]
Abstract
TLR-7/8 agonists are a well-known class of vaccine adjuvants, with a leading example now included in Covaxin, a licensed human COVID-19 vaccine. This thereby provides the opportunity to develop newer, more potent adjuvants based on structure-function studies of these classes of compounds. Imidazoquinoline-based TLR7/8 agonists are the most potent, but when used as a vaccine adjuvant side effects can arise due to diffusion from the injection site into a systemic circulation. In this work, we sought to address this issue through structural modifications in the agonists to enhance their adsorption capacity to the classic adjuvant alum. We selected a potent TLR7-selective agonist, BBIQ (EC50 = 0.85 μM), and synthesized polyphenolic derivatives to assess their TLR7 agonistic activity and adjuvant potential alone or in combination with alum. Most of the phenolic derivatives were more active than BBIQ and, except for 12b, all were TLR7 specific. Although the synthesized compounds were less active than resiquimod, the immunization data on combination with alum, specifically the IgG1, IgG2b and IgG2c responses, were superior in comparison to BBIQ as well as the reference standard resiquimod. Compound 12b was 5-fold more potent (EC50 = 0.15 μM in TLR7) than BBIQ and induced double the IgG response to SARS-CoV-2 and hepatitis antigens. Similarly, compound 12c (EC50 = 0.31 μM in TLR7) was about 3-fold more potent than BBIQ and doubled the IgG levels. Even though compound 12d exhibited low TLR7 activity (EC50 = 5.13 μM in TLR7), it demonstrated superior adjuvant results, which may be attributed to its enhanced alum adsorption capability as compared with BBIQ and resiquimod. Alum-adsorbed polyphenolic TLR7 agonists thereby represent promising combination adjuvants resulting in a balanced Th1/Th2 immune response.
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Affiliation(s)
- Kushvinder Kumar
- Department
of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Binita Sihag
- Department
of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Madhuri T. Patil
- Mehr
Chand Mahajan DAV College for Women, Sector 36A, Chandigarh 160 036, India
| | - Rahul Singh
- Department
of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Isaac G. Sakala
- Vaxine
Pty Ltd, 11 Walkley Avenue, Warradale, South Australia 5046, Australia
- College
of Medicine and Public Health, Flinders
University, Bedford Park, South Australia 5042, Australia
| | - Yoshikazu Honda-Okubo
- Vaxine
Pty Ltd, 11 Walkley Avenue, Warradale, South Australia 5046, Australia
- College
of Medicine and Public Health, Flinders
University, Bedford Park, South Australia 5042, Australia
| | - Kamal Nain Singh
- Department
of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
| | - Nikolai Petrovsky
- Vaxine
Pty Ltd, 11 Walkley Avenue, Warradale, South Australia 5046, Australia
- College
of Medicine and Public Health, Flinders
University, Bedford Park, South Australia 5042, Australia
| | - Deepak B. Salunke
- Department
of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
- National
Interdisciplinary Centre of Vaccines, Immunotherapeutics and Antimicrobials
(NICOVIA), Panjab University, Chandigarh 160 014, India
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Analysis of N 15-rat growth hormone after incubation with rat subcutaneous tissue and immune cells using ultra-pressure chromatography-mass spectrometry. Anal Biochem 2021; 634:114425. [PMID: 34678250 DOI: 10.1016/j.ab.2021.114425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/22/2021] [Accepted: 10/14/2021] [Indexed: 11/21/2022]
Abstract
Therapeutic proteins (TPs) are exposed to various immune cells like macrophages and neutrophils, especially after subcutaneous (SC) administration. It is well known that the immune cells can generate reactive oxygen species (ROS) and this may lead to oxidation of TPs. The oxidation can occur in the SC tissue after SC administration, during distribution to the immune organs like lymph nodes and spleen, and even in the blood circulation. The oxidation can lead to alteration of their pharmacokinetics and efficacy. Therefore, it is important to study the oxidation of TPs in the biological matrices using ultra-pressure chromatography-mass spectrometry. Rat growth hormone (rGH) was selected as a test protein due to its similarity with human growth hormone (hGH), which is widely used for treatment of growth hormone deficiency. In this manuscript, we have summarized sample processing strategy and ultra-pressure chromatography-mass spectrometry methodology to identify rGH and its degradation products after ex-vivo incubation with rat SC tissue, and in vitro incubation with rat splenocytes and canine peripheral blood mononuclear cells (cPBMCs) as a model foreign host species. We did not observe oxidation of rGH in these biological matrices. This could be due to very minor yields of oxidation products, lack of sensitivity of the mass spectrometry method, loss of protein during sample processing, rapid turnover of oxidized protein or a combination of all factors.
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Velmurugan K, Don D, Kannan R, Selvaraj C, VishnuPriya S, Selvaraj G, Singh SK, Nandhakumar R. Synthesis, antibacterial, anti-oxidant and molecular docking studies of imidazoquinolines. Heliyon 2021; 7:e07484. [PMID: 34286142 PMCID: PMC8273425 DOI: 10.1016/j.heliyon.2021.e07484] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/26/2021] [Accepted: 07/01/2021] [Indexed: 12/24/2022] Open
Abstract
Quinoline and imidazole derivatives have been playing a significant role in functional bioactivities and were potentially used as antibacterial, antifungal, anticancer, and anti-inflammatory drugs. Owing to the limitation of drug resistance, herein we synthesized thio-, chloro-, and hydroxyl-functionalized various imidazoquinolines by molecular hybridization approach. All the imidazoquinoline derivatives were examined for their antibacterial activity against selected bacterial pathogens by the agar well diffusion method. In addition, the anti-oxidant efficacy of imidazoquinolines was also tested using ferric reducing antioxidant power (FRAP). Among them, electron-withdrawing (-Cl) substituent containing imidazoquinoline 5f showed higher antibacterial and anti-oxidant activities than other imidazoquinolines and reached the effectiveness of the standard. In addition, compounds 4f, 5e, and 3f showed moderate antibacterial activity and other derivatives displayed weak activity against various pathogens. Molecular docking studies were also performed on selected imidazoquinoline derivatives (3f, 4f, and 5f), which showed high docking score and strong binding energy values. These results revealed that thio-imidazoquinoline could assist as a prototype for the designing of multidrug-resistant antibiotics against various microbial organisms.
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Affiliation(s)
- K Velmurugan
- Department of Applied Chemistry, Karunya Institute of Technology and Sciences (Deemed-to-be University), Karunya Nagar, Coimbatore, 641 114, India
| | - Derin Don
- Department of Applied Chemistry, Karunya Institute of Technology and Sciences (Deemed-to-be University), Karunya Nagar, Coimbatore, 641 114, India
| | - Rajesh Kannan
- Department of Microbiology, Bharathidasan Univeristy, Tiruchirappalli, 620 024, India
| | - C Selvaraj
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, 630004, Tamil Nadu, India
| | - S VishnuPriya
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, 91120, Israel
| | - G Selvaraj
- Centre for Interdisciplinary Sciences-Computational Life Sciences, College of Food Science and Technology, Henan University of Technology, Zhengzhou, China
| | - S K Singh
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, 630004, Tamil Nadu, India
| | - R Nandhakumar
- Department of Applied Chemistry, Karunya Institute of Technology and Sciences (Deemed-to-be University), Karunya Nagar, Coimbatore, 641 114, India
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Talukdar A, Ganguly D, Roy S, Das N, Sarkar D. Structural Evolution and Translational Potential for Agonists and Antagonists of Endosomal Toll-like Receptors. J Med Chem 2021; 64:8010-8041. [PMID: 34107682 DOI: 10.1021/acs.jmedchem.1c00300] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Toll-like receptors (TLRs) are members of a large family of evolutionarily conserved pattern recognition receptors (PRRs), which serve as key components of the innate immune system by playing a pivotal role in sensing "nonself" ligands. Endosomal TLRs (TLR3, TLR7, TLR8, and TLR9) can recognize pathogen-derived nucleic acid and initiate an innate immune response because they react against both self- and non-self-origin nucleic acid molecules. Accordingly, both receptor agonists and antagonists are potentially useful in disparate clinical contexts and thus are globally sought after. Recent research has revealed that agonists and antagonists share an overlapping binding region. This Perspective highlights rational medicinal chemistry approaches to elucidate the structural attributes of small molecules capable of agonism or antagonism or of elegantly switching between the two. The structural evolution of different chemotypes can provide the framework for the future development of endosomal TLR agonists and antagonists.
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Affiliation(s)
- Arindam Talukdar
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India.,Academy of Scientific and Innovative Research, Ghaziabad 201002, Uttar Pradesh, India
| | - Dipyaman Ganguly
- IICB-Translational Research Unit of Excellence, Department of Cancer Biology and Inflammatory Disorders, CSIR-Indian Institute of Chemical Biology, CN6, Sector V, Salt Lake, Kolkata 700091, West Bengal, India.,Academy of Scientific and Innovative Research, Ghaziabad 201002, Uttar Pradesh, India
| | - Swarnali Roy
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India
| | - Nirmal Das
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India.,Academy of Scientific and Innovative Research, Ghaziabad 201002, Uttar Pradesh, India
| | - Dipika Sarkar
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India
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Kaushik D, Kaur A, Petrovsky N, Salunke DB. Structural evolution of toll-like receptor 7/8 agonists from imidazoquinolines to imidazoles. RSC Med Chem 2021; 12:1065-1120. [PMID: 34355178 DOI: 10.1039/d1md00031d] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/27/2021] [Indexed: 12/11/2022] Open
Abstract
Several synthetic heterocyclic small molecules like imiquimod, resiquimod, CL097, CL075, bromopirone, tilorone, loxoribine and isatoribine demonstrated TLR7/8 agonistic activity and relatively modest structural changes in such molecules result in major variation in the TLR7 and/or TLR8 activity. A strict dependency of the electronic configuration of the heterocyclic system was also observed to influence the agonistic activity. In the present review, an evolution of imidazole based TLR7/8 agonist from imidazoquinoline based scaffold is delineated along with the elaboration of detailed structure activity relationship (SAR) in each chemotype. The structural and activity details of not only the active compounds but also the related inactive compounds are included to better understand the SAR. TLR7/8 agonists are emerging as promising vaccine adjuvant candidates and the present SAR and structural information will provide a road map towards the identification of more potent and appropriate candidates for further drug discovery.
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Affiliation(s)
- Deepender Kaushik
- Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University Chandigarh 160014 India
| | - Arshpreet Kaur
- Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University Chandigarh 160014 India
| | - Nikolai Petrovsky
- Vaxine Pty Ltd 11 Walkley Avenue Warradale 5046 Australia.,College of Medicine and Public Health, Flinders University Bedford Park 5042 Australia
| | - Deepak B Salunke
- Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University Chandigarh 160014 India .,National Interdisciplinary Centre of Vaccine, Immunotherapeutics and Antimicrobials, Panjab University Chandigarh 160014 India
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