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  1. Article ; Online: The role of human C5a as a non-genomic target in corticosteroid therapy for management of severe COVID19.

    Das, Aurosikha / Rana, Soumendra

    Computational biology and chemistry

    2021  Volume 92, Page(s) 107482

    Abstract: Complement system plays a dual role; physiological as well as pathophysiological. While physiological role protects the host, pathophysiological role can substantially harm the host, by triggering several hyper-inflammatory pathways, referred as " ... ...

    Abstract Complement system plays a dual role; physiological as well as pathophysiological. While physiological role protects the host, pathophysiological role can substantially harm the host, by triggering several hyper-inflammatory pathways, referred as "hypercytokinaemia". Emerging clinical evidence suggests that exposure to severe acute respiratory syndrome coronavirus-2 (SARS-CoV2), tricks the complement to aberrantly activate the "hypercytokinaemia" loop, which significantly contributes to the severity of the COVID19. The pathophysiological response of the complement is usually amplified by the over production of potent chemoattractants and inflammatory modulators, like C3a and C5a. Therefore, it is logical that neutralizing the harmful effects of the inflammatory modulators of the complement system can be beneficial for the management of COVID19. While the hunt for safe and efficacious vaccines were underway, polypharmacology based combination therapies were fairly successful in reducing both the morbidity and mortality of COVID19 across the globe. Repurposing of small molecule drugs as "neutraligands" of C5a appears to be an alternative for modulating the hyper-inflammatory signals, triggered by the C5a-C5aR signaling axes. Thus, in the current study, few specific and non-specific immunomodulators (azithromycin, colchicine, famotidine, fluvoxamine, dexamethasone and prednisone) generally prescribed for prophylactic usage for management of COVID19 were subjected to computational and biophysical studies to probe whether any of the above drugs can act as "neutraligands", by selectively binding to C5a over C3a. The data presented in this study indicates that corticosteroids, like prednisone can have potentially better selectively (K
    MeSH term(s) Binding Sites ; COVID-19/pathology ; Complement C5a/antagonists & inhibitors ; Complement C5a/chemistry ; Gene Expression Regulation/drug effects ; Humans ; Molecular Docking Simulation ; Prednisone/chemistry ; Protein Binding ; Protein Conformation ; SARS-CoV-2 ; COVID-19 Drug Treatment
    Chemical Substances Complement C5a (80295-54-1) ; Prednisone (VB0R961HZT)
    Language English
    Publishing date 2021-04-05
    Publishing country England
    Document type Journal Article
    ISSN 1476-928X
    ISSN (online) 1476-928X
    DOI 10.1016/j.compbiolchem.2021.107482
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Interaction of Human C5a with the Major Peptide Fragments of C5aR1

    Aurosikha Das / Lalita Mohan Behera / Soumendra Rana

    ACS Omega, Vol 6, Iss 35, Pp 22876-

    Direct Evidence in Support of “Two-Site” Binding Paradigm

    2021  Volume 22887

    Keywords Chemistry ; QD1-999
    Language English
    Publishing date 2021-08-01T00:00:00Z
    Publisher American Chemical Society
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Ternary model structural complex of C5a, C5aR2, and β-arrestin1.

    Gupta, Pulkit Kr / Das, Aurosikha / Singh, Aditi / Rana, Soumendra

    Journal of biomolecular structure & dynamics

    2023  , Page(s) 1–17

    Abstract: Complement component fragment 5a (C5a) is one of the potent proinflammatory modulators of the complement system. C5a recruits two genomically related G protein-coupled receptors (GPCRs), like C5aR1 and C5aR2, constituting a binary complex. The C5a-C5aR1/ ... ...

    Abstract Complement component fragment 5a (C5a) is one of the potent proinflammatory modulators of the complement system. C5a recruits two genomically related G protein-coupled receptors (GPCRs), like C5aR1 and C5aR2, constituting a binary complex. The C5a-C5aR1/C5aR2 binary complexes involve other transducer proteins like heterotrimeric G-proteins and β-arrestins to generate the fully active ternary complexes that trigger intracellular signaling through downstream effector molecules in tissues. In the absence of structural data, we had recently developed highly refined model structures of C5aR2 in its inactive (free), meta-active (complexed to the CT-peptide of C5a), and active (complexed to C5a) state embedded to a model palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer. Compared to C5aR1, C5aR2 is established as a noncanonical GPCR, as it recruits and signals through β-arrestins rather than G-proteins. Notably, structural understanding of the ternary complex involving C5a-C5aR2-β-arrestin is currently unknown. The current study has attempted to fill the gap by generating a highly refined, fully active ternary model structural complex of the C5a-C5aR2-β-arrestin1 embedded in a model POPC bilayer. The computational modeling, 500 ns molecular dynamics (MD) studies, and the principal component analysis (PCA), including the molecular mechanics Poisson-Boltzmann surface area (MM PBSA) based data presented in this study, provide an experimentally testable hypothesis about C5a-C5aR2-β-arrestin1 extendable to other such ternary systems. The model ternary complex of C5a-C5aR2-β-arrestin1 will further enrich the current structural understanding related to the interaction of β-arrestins with the C5a-C5aR2 system.Communicated by Ramaswamy H. Sarma.
    Language English
    Publishing date 2023-07-26
    Publishing country England
    Document type Journal Article
    ZDB-ID 49157-3
    ISSN 1538-0254 ; 0739-1102
    ISSN (online) 1538-0254
    ISSN 0739-1102
    DOI 10.1080/07391102.2023.2239927
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: C5aR2 receptor: The genomic twin of the flamboyant C5aR1.

    Das, Aurosikha / Gupta, Pulkit K / Rana, Soumendra

    Journal of cellular biochemistry

    2022  Volume 123, Issue 11, Page(s) 1841–1856

    Abstract: The complement fragment C5a is one of the most potent proinflammatory glycoproteins liberated by the activation of the biochemical cascade of the complement system. C5a is established to interact with a set of genomically related transmembrane receptors, ...

    Abstract The complement fragment C5a is one of the most potent proinflammatory glycoproteins liberated by the activation of the biochemical cascade of the complement system. C5a is established to interact with a set of genomically related transmembrane receptors, like C5aR1 (CD88, C5aR) and C5aR2 (GPR77, C5L2) with comparable affinity. The C5aR1 is a classical G-protein-coupled receptor (GPCR), whereas C5aR2 is a nonclassical GPCR that tailors immune cell activity potentially through β-arrestins rather than G-proteins. Currently, the exact function of the C5aR2 is actively debated in the context of C5aR1, even though both C5aR1 and C5aR2 are coexpressed on myriads of tissues. The functional relevance of C5aR2 appears to be context-dependent compared to the C5aR1, which has received enormous attention for its role in both acute and chronic inflammatory diseases. In addition, the structure of C5aR2 and its interaction specificity toward C5a is not structurally elucidated in the literature so far. The current study has attempted to close the gap by generating highly refined model structures of C5aR2, respectively in free (inactive), complexed to C-terminal peptide of C5a (meta-active) and the C5a (active), embedded to a model palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer. The computational modeling and the 1.5-μs molecular dynamics data presented in the current study are expected to further enrich the understanding of C5a-C5aR2 interaction compared to C5a-C5aR1, which will surely help in elaborating the currently debated biological function of C5aR2 better in the foreseeable future.
    MeSH term(s) Complement C5a/genetics ; Complement C5a/metabolism ; beta-Arrestins ; Genomics ; Receptor, Anaphylatoxin C5a/genetics
    Chemical Substances Complement C5a (80295-54-1) ; beta-Arrestins ; Receptor, Anaphylatoxin C5a
    Language English
    Publishing date 2022-08-17
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 392402-6
    ISSN 1097-4644 ; 0730-2312
    ISSN (online) 1097-4644
    ISSN 0730-2312
    DOI 10.1002/jcb.30320
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Interaction of Human C5a with the Major Peptide Fragments of C5aR1: Direct Evidence in Support of "Two-Site" Binding Paradigm.

    Das, Aurosikha / Behera, Lalita Mohan / Rana, Soumendra

    ACS omega

    2021  Volume 6, Issue 35, Page(s) 22876–22887

    Abstract: The C5a receptor's (C5aR1) physiological function in various tissues depends on its high-affinity binding to the cationic proinflammatory glycoprotein C5a, produced during the activation of the complement system. However, an overstimulated complement can ...

    Abstract The C5a receptor's (C5aR1) physiological function in various tissues depends on its high-affinity binding to the cationic proinflammatory glycoprotein C5a, produced during the activation of the complement system. However, an overstimulated complement can quickly alter the C5a-C5aR1 function from physiological to pathological, as has been noted in the case of several chronic inflammation-induced diseases like asthma, lung injury, multiorgan failure, sepsis, and now COVID-19. In the absence of the structural data, the current study provides the confirmatory biophysical validation of the hypothesized "two-site" binding interactions of C5a, involving (i) the N-terminus (NT) peptide ("Site1") and (ii) the extracellular loop 2 (ECL2) peptide of the extracellular surface (ECS) of the C5aR1 ("Site2"), as illustrated earlier in the reported model structural complex of C5a-C5aR1. The biophysical and computational data elaborated in the study provides an improved understanding of the C5a-C5aR1 interaction at an atomistic resolution, highlighting the energetic importance of the aspartic acids on the NT-peptide of C5aR1 toward binding of C5a. The current study can potentially advance the search and optimization of new-generation alternative "antibodies" as well as "neutraligands" targeting the C5a to modulate its interaction with C5aR1.
    Language English
    Publishing date 2021-08-26
    Publishing country United States
    Document type Journal Article
    ISSN 2470-1343
    ISSN (online) 2470-1343
    DOI 10.1021/acsomega.1c03400
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Neutraligands of C5a can potentially occlude the interaction of C5a with the complement receptors C5aR1 and C5aR2.

    Das, Aurosikha / Ghosh, Manaswini / Gupta, Pulkit Kr / Rana, Soumendra

    Journal of cellular biochemistry

    2022  Volume 124, Issue 2, Page(s) 266–281

    Abstract: The complement system is central to the rapid immune response witnessed in vertebrates and invertebrates, which plays a crucial role in physiology and pathophysiology. Complement activation fuels the proteolytic cascade, which produces several complement ...

    Abstract The complement system is central to the rapid immune response witnessed in vertebrates and invertebrates, which plays a crucial role in physiology and pathophysiology. Complement activation fuels the proteolytic cascade, which produces several complement fragments that interacts with a distinct set of complement receptors. Among all the complement fragments, C5a is one of the most potent anaphylatoxins, which exerts solid pro-inflammatory responses in a myriad of tissues by binding to the complement receptors such as C5aR1 (CD88, C5aR) and C5aR2 (GPR77, C5L2), which are part of the rhodopsin subfamily of G-protein coupled receptors. In terms of signaling cascade, recruitment of C5aR1 or C5aR2 by C5a triggers the association of either G-proteins or β-arrestins, providing a protective response under normal physiological conditions and a destructive response under pathophysiological conditions. As a result, both deficiency and unregulated activation of the complement lead to clinical conditions that require therapeutic intervention. Indeed, complement therapeutics targeting either the complement fragments or the complement receptors are being actively pursued by both industry and academia. In this context, the model structural complex of C5a-C5aR1 interactions, followed by a biophysical evaluation of the model complex, has been elaborated on earlier. In addition, through the drug repurposing strategy, we have shown that small molecule drugs such as raloxifene and prednisone may act as neutraligands of C5a by effectively binding to C5a and altering its biologically active molecular conformation. Very recently, structural models illustrating the intermolecular interaction of C5a with C5aR2 have also been elaborated by our group. In the current study, we provide the biophysical validation of the C5a-C5aR2 model complex by recruiting major synthetic peptide fragments of C5aR2 against C5a. In addition, the ability of the selected neutraligands to hinder the interaction of C5a with the peptide fragments derived from both C5aR1 and C5aR2 has also been explored. Overall, the computational and experimental data provided in the current study supports the idea that small molecule drugs targeting C5a can potentially neutralize C5a's ability to interact effectively with its cognate complement receptors, which can be beneficial in modulating the destructive signaling response of C5a under pathological conditions.
    MeSH term(s) Animals ; Signal Transduction ; Receptors, Complement ; beta-Arrestins
    Chemical Substances Receptors, Complement ; beta-Arrestins
    Language English
    Publishing date 2022-12-24
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 392402-6
    ISSN 1097-4644 ; 0730-2312
    ISSN (online) 1097-4644
    ISSN 0730-2312
    DOI 10.1002/jcb.30360
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Resveratrol binding to human complement fragment 5a (

    Mishra, Richa / Das, Aurosikha / Rana, Soumendra

    Journal of biomolecular structure & dynamics

    2020  Volume 39, Issue 5, Page(s) 1766–1780

    Abstract: Resveratrol (RSV), the active pharmaceutical ingredient (API) found in several fruits, nuts and marketed nutraceuticals is one of the promiscuous phytoalexin known to promote good health. The health benefits of RSV could be due to its antioxidant ... ...

    Abstract Resveratrol (RSV), the active pharmaceutical ingredient (API) found in several fruits, nuts and marketed nutraceuticals is one of the promiscuous phytoalexin known to promote good health. The health benefits of RSV could be due to its antioxidant activity or its direct interaction with target proteins, resulting modulation of several cells signaling and inflammatory pathways. Among many of its disease preventing activities, RSV has been shown to ameliorate inflammation by directly binding the COX-1 and COX-2 enzymes, the established targets of common non-steroidal anti-inflammatory drugs (NSAIDs). As a follow up to our recent study, we have now identified that RSV can also directly target
    MeSH term(s) Complement C5a ; Humans ; Inflammation ; Molecular Dynamics Simulation ; Receptor, Anaphylatoxin C5a ; Receptors, Complement ; Resveratrol ; Signal Transduction
    Chemical Substances Receptor, Anaphylatoxin C5a ; Receptors, Complement ; Complement C5a (80295-54-1) ; Resveratrol (Q369O8926L)
    Language English
    Publishing date 2020-03-17
    Publishing country England
    Document type Journal Article
    ZDB-ID 49157-3
    ISSN 1538-0254 ; 0739-1102
    ISSN (online) 1538-0254
    ISSN 0739-1102
    DOI 10.1080/07391102.2020.1738958
    Database MEDical Literature Analysis and Retrieval System OnLINE

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