Browsing by Author "Singh, Sunil Kumar"
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Item Autoinducer N-(3-oxododecanoyl)-L-homoserine lactone induces calcium and reactive oxygen species-mediated mitochondrial damage and apoptosis in blood platelets(Academic Press, 2021-02-23T00:00:00) Yadav, Vivek Kumar; Singh, Pradeep Kumar; Sharma, Deepmala; Pandey, Himanshu; Singh, Sunil Kumar; Agarwal, VishnuAcylated homoserine lactones (AHL) such as N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12 HSL) and N-butyryl-L-homoserine lactone (C4 HSL) are the most common autoinducer molecules in Pseudomonas aeruginosa. These AHL molecules not only regulate the expression of virulence factors but also have been shown to interfere with the host cell and modulate its functions. Recently, we reported that 3-oxo-C12 HSL but not C4 HSL causes cytosolic Ca2+ rise and ROS production in platelets. In this study, we examined the potential of AHLs to induce apoptosis in the human blood platelet. Our result showed that 3-oxo-C12 HSL but not C4 HSL causes phosphatidylserine (PS) exposure, mitochondrial dysfunction (mitochondrial transmembrane potential loss, and mitochondrial permeability transition pore (mPTP) formation). Besides, 3-oxo-C12 HSL also inhibited thrombin-induced platelet aggregation and clot retraction. The pretreatment of an intracellular calcium chelator BAPTA-AM or ROS inhibitor (DPI) significantly attenuated the 3-oxo-C12 HSL induced apoptotic characters such as PS exposure and mitochondrial dysfunctions. These data, including our previous findings, confirmed that 3-oxo-C12 HSL induced intracellular Ca2+ mediated ROS production results in the activation and subsequent induction of apoptotic features in platelets. Our results demonstrated that the 3-oxo-C12 HSL modulates the functions of platelets that may cause severe thrombotic complications in P. aeruginosa infected individuals. � 2021 Elsevier LtdItem CHAPTER 9: Nanomaterial-Blood Interactions: A Biomedical Perspective(Royal Society of Chemistry, 2019) Singh, Priti; Singh, Sunil KumarWithin the short span of a decade, nanotechnology has gained tremendous recognition in diagnostic and therapeutic applications owing to its unique physiochemical properties. Whenever nanomaterials (NMs) are intravenously injected inside the biological system, NMs encounter the complex physiological environment of blood. Blood is a connective tissue consisting of blood cells, plasma proteins and lipoproteins, and a coagulation system that maintains the haemostasis of the body. NMs can interact with blood constituents and trigger patho-physiological events such as complement activation and thrombosis. Therefore, in this chapter, the roles of blood constituents in a biological system and interactions between NMs and blood components is critically reviewed. The shape, size, functionalisation and surface charge of NMs may be deciding factors for their adverse toxic effects. A critical analysis of nanomaterial-blood interactions will help with designing engineered NMs and manipulating their properties for impeccable applications in nanomedicine. © The Royal Society of Chemistry 2019.Item Evaluation of mean platelet volume and platelet count in ischemic stroke and its subtypes: focus on degree of disability and thrombus formation(Taylor and Francis Ltd., 2022-08-27T00:00:00) Ludhiadch, Abhilash; Yadav, Pooja; Singh, Sunil Kumar; Sulena; Munshi, AnjanaBackground: Platelets are crucial players in thrombus formation during ischemic stroke. Platelet (PLT) count and Mean platelet volume (MPV) are important parameters that affect platelet functions. The current study has been carried out with an aim to evaluate the association of MPV and PLT count with ischemic stroke in a population from the Malwa region of Punjab. Material and Methods: The study included one hundred and fifty ischemic stroke patients. The extent of disability occurs by stroke was measured by mRS. MPV and PLT was evaluated using cell counter. Further, PLT count was confirmed in 50% of patients using flow cytometer. Clot formation rate was evaluated using Sonoclot Coagulation and Platelet Function Analyzer. All the statistical analysis was carried out using SPSS. Results: A significant association of increased MPV (p < 0.02) was found with the ischemic stroke. However, PLT count did not show a significant association with the disease (p < 0.07). Further, a stepwise multiple logistic regression (MLR) analysis controlling the other confounding risk factors evaluated the association of hypertension and MPV with the disease. Patients with higher mRS were found to have high MPV values confirming that higher MPV is correlated with disability occurs by ischemic stroke. MPV was also found to be significantly associated with large artery atherosclerosis (p < 0.001). Clot formation analysis revealed that ischemic stroke patients bear higher clot rate (CR) and Platelet function (PF) values. Conclusions: Elevated MPV is an independent risk factor for Ischemic stroke along with hypertension. In addition, higher MPV associated significantly with stroke disability as well. � 2022 Informa UK Limited, trading as Taylor & Francis Group.Item Genetic and epigenetic markers in colorectal cancer screening: recent advances(Taylor & Francis, 2017) Singha, Manish Pratap; Rai, Sandhya; Suyal, Shradha; Singh, Sunil Kumar; Singh, Nand Kumar; Agrawal, Akash; Srivastava, SameerIntroduction: Colorectal cancer (CRC) is a heterogenous disease which develops from benign intraepithelial lesions known as adenomas to malignant carcinomas. Acquired alterations in Wnt signaling, TGFβ, MAPK pathway genes and clonal propagation of altered cells are responsible for this transformation. Detection of adenomas or early stage cancer in asymptomatic patients and better prognostic and predictive markers is important for improving the clinical management of CRC. Area covered: In this review, the authors have evaluated the potential of genetic and epigenetic alterations as markers for early detection, prognosis and therapeutic predictive potential in the context of CRC. We have discussed molecular heterogeneity present in CRC and its correlation to prognosis and response to therapy. Expert commentary: Molecular marker based CRC screening methods still fail to gain trust of clinicians. Invasive screening methods, molecular heterogeneity, chemoresistance and low quality test samples are some key challenges which need to be addressed in the present context. New sequencing technologies and integrated omics data analysis of individual or population cohort results in GWAS. MPE studies following a GWAS could be future line of research to establish accurate correlations between CRC and its risk factors. This strategy would identify most reliable biomarkers for CRC screening and management.Item In silico evaluation of natural compounds to confirm their anti-DNA gyrase activity(Springer, 2023-06-03T00:00:00) Kumar, Reetesh; Srivastava, Yogesh; Maji, Somnath; Siddiqui, Seemab; Tyagi, Rajeev Kumar; Muthuramalingam, Pandiyan; Singh, Sunil Kumar; Tiwari, Savitri; Verma, Geetika; de Toledo Thomazella, Daniela Paula; Shin, Hyunsuk; Prajapati, Dinesh Kumar; Rai, Pankaj Kumar; Beura, Samir Kumar; Panigrahi, Abhishek Ramachandra; de Moraes, Fabio Rogerio; Rao, Pasupuleti VisweswaraThe slow clearance of bacteria owing to drug resistance to the currently available antibiotics has been a global public health issue. The development of antibiotic resistance in Staphylococcus aureus has become prevalent in community-acquired infections, posing a significant challenge. DNA gyrase, an enzyme essential in all bacteria but absent in higher eukaryotes, emerges as an attractive target for novel antibacterial agents. This type II topoisomerase introduces negative supercoils in double-stranded DNA, at the expense of ATP, during DNA replication. In this study, we conducted a comprehensive screening of natural compound libraries from the ZINC database using different computational approaches targeting DNA gyrase activity. We identified five promising compounds following a detailed screening of drug-like compounds using pharmacokinetic-based studies, including the determination of the compound absorption, distribution, metabolism, excretion, and toxicity. Furthermore, based on protein�ligand docking studies, we showed the position, orientation, and binding affinity of the selected compounds within the active site of DNA gyrase. Overall, our study provides a primary reference to explore the molecular mechanisms associated with the antibacterial activity of the selected compounds, representing an important step toward the discovery of novel DNA gyrase inhibitors. Further investigation involving structural optimization as well as comprehensive in vivo and in vitro evaluations are necessary to fully explore the potential of these chemicals as effective antibacterial agents. Graphical abstract: [Figure not available: see fulltext.]. � 2023, The Author(s) under exclusive licence to Archana Sharma Foundation of Calcutta.Item Mechanism underlying N-(3-oxo-dodecanoyl)-L-homoserine lactone mediated intracellular calcium mobilization in human platelets(Academic Press, 2019) Yadav, V.K; Singh, P.K; Sharma, D; Singh, Sunil Kumar; Agarwal,V.Acyl-homoserine lactones (AHLs), are the key autoinducer molecules that mediate Pseudomonas aeruginosa associated quorum sensing. P. aeruginosa produces two types of AHLs; N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12 HSL) and N-butyryl-L-homoserine lactone (C4 HSL). AHLs are not only regulating the virulence gene of bacteria but also influence the host cell functions by interkingdom signaling. In this study, we explored the mechanism of AHLs induced calcium mobilization in human platelets. We found that 3-oxo-C12 HSL but not C4 HSL induces intracellular calcium release. 3-oxo-C12 HSL induced calcium mobilization was majorly contributed from the dense tubular system (DTS). Furthermore, 3-oxo-C12 HSL also stimulates the store-operated Ca2+ entry (SOCE) in platelet. Intracellular calcium rise was significantly lowered in rotenone, and bafilomycin pre-treated platelets suggesting partial involvement of mitochondria and acidic vacuoles. The significant effect of 3-oxo-C12 HSL on calcium mobilization can alter the platelet functions that might results in thrombotic disorders in individuals infected with P. aeruginosa. © 2019Item Mesoporous nanosilica: A thromboprotective nanomaterial for biomedical applications(Elsevier Ltd, 2022-06-17T00:00:00) Singh, Priti; Srivastava, Sameer; Singh, Sunil KumarNanosilica is widely employed in various biomedical applications because of their tailorable physiochemical properties and excellent biocompatibility. In the present study, we have evaluated interaction of nanosilica with important coagulation components, such as platelets, a highly sensitive cell found in the blood, and coagulation proteins. Mesoporous silica nanoparticles (MSNs) were prepared using sol-gel process and characterized by FESEM and TEM to find out the size and shape of the particles. Different platelet functional parameters including platelet adhesion, aggregation, activation, secretion, clot formation and clot retraction-based studies have been carried out to investigate the impact of synthesized nanosilica on the blood coagulation system. Besides, ROS generation and increase in intracellular calcium was also monitored as they play a pivotal role in regulating platelet functions. The complete detailed study revealed that MSNs neither has stimulatory action towards platelets nor do they show any effective interaction with coagulation proteins. � 2022 Elsevier LtdItem Peculiar sleep features in sympatric species may contribute to the temporal segregation(Springer Science and Business Media Deutschland GmbH, 2022-10-22T00:00:00) Mishra, Sukriti; Sharma, Nisha; Singh, Sunil Kumar; Lone, Shahnaz RahmanSleep is conserved in the animal kingdom and plays a pivotal role in the adaptation of species. Sleep in Drosophila melanogaster is defined as any continuous 5 min of quiescence, shows a�prominent siesta, and consolidated nighttime sleep. Here, we analyzed the sleep of�two other species D. malerkotliana�(DMK) and�D. ananassae�(DA), and compared it with�D. melanogaster�(DM). The DMK males and females have siesta like DM. However, unlike DM, flies continue to sleep beyond siesta till the evening. DA has a less prominent siesta compared to DM and DMK. In the morning, DA took a longer time to respond to the lights ON and continued to sleep for at least half an hour. The nighttime sleep of the DA flies is higher than the other two species. Average length of sleep episode is three times more than that of DM and DMK with few wake episodes. Thus, the nighttime sleep of DA�males and females is deep and needs exposure to more potent stimuli to wake up relative to the other two species. DA�males and females show higher sleep rebound than the other two species, suggesting the robustness of sleep homeostasis. Although total sleep of DMK and DA is similar, DA is a day-active species with highly consolidated night sleep. DMK, like DM, is a crepuscular species with a midday siesta.�Thus, our results suggest that temporal partitioning of sleep, in sympatric species may contribute to temporal segregation. � 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Platelet-derived microvesicles activate human platelets via intracellular calcium mediated reactive oxygen species release(Academic Press Inc., 2022-08-28T00:00:00) Yadav, Pooja; Beura, Samir Kumar; Panigrahi, Abhishek Ramachandra; Bhardwaj, Taniya; Giri, Rajanish; Singh, Sunil KumarPlatelet-derived microvesicles (PMVs) are the most abundant microvesicles in circulation, originating from blood platelets via membrane blebbing. PMVs act as biological cargo carrying key molecules from platelets, including immunomodulatory molecules, growth factors, clotting molecules, and miRNAs that can regulate recipient cellular functions. Formation and release of PMVs play an essential role in the pathophysiology of vascular diseases such as hemostasis, inflammation, and thrombosis. Platelet activation is considered the critical event in thrombosis, and a growing number of evidence suggests that oxidative stress-mediated signaling plays a significant role in platelet activation. Ca2+ is a notable player in the generation of ROS in platelets. Reports have established that microvesicles exhibit dual nature in redox mechanisms as they possess both pro-oxidant and antioxidant machinery. However, the impact of PMVs and their ROS machinery on platelets is still a limited explored area. Here, we have demonstrated that PMVs mediate platelet activation via intracellular ROS generation. PMVs interacted with platelets and induced calcium-mediated intracellular ROS production via NADPH oxidase (NOX), leading to platelet activation. Our findings will open up new insights into the tangible relationship of PMVs with platelets and will further contribute to the therapeutic aspects of PMVs in vascular injury and tissue remodeling. � 2022Item Redefining oxidative stress in Alzheimer's disease: Targeting platelet reactive oxygen species for novel therapeutic options(Elsevier Inc., 2022-08-01T00:00:00) Beura, Samir Kumar; Dhapola, Rishika; Panigrahi, Abhishek Ramachandra; Yadav, Pooja; Reddy, Dibbanti Harikrishna; Singh, Sunil KumarAlzheimer's disease (AD), a progressive neurodegenerative disorder, is considered one of the most common causes of dementia worldwide, accounting for about 80 % of all dementia cases. AD is manifested by the extraneuronal deposition of senile plaques of amyloid beta (A?) and intraneuronal accumulation of neurofibrillary tangles of phosphorylated tau. The impaired proteostasis of these filamentous A? and tau is significantly regulated by reactive oxygen species (ROS). ROS-induced oxidative stress (OS) is the cardinal cause behind neuroinflammation-triggered neurodegeneration during AD. Besides ROS-induced neuro-inflammation, AD is also associated with cerebrovascular dysfunction, where platelet primarily plays a significant role in blood-vessel integrity and tissue repair. Though platelets are the circulatory cell fragments that play predominant roles in thrombosis and hemostasis, their contributions to other physiological functions are also being elucidated. Surprisingly, platelets contribute about 90 % of the circulatory A? and share striking similarities with neurons in several aspects, including different neurotransmitters and their cognate receptors, thus considering platelets as potential peripheral models for AD. Interestingly, platelet structural and functional dysfunctions are evident in AD, where ROS production is associated with platelet hyperactivity. Although activated platelet carries several vital enzymes and immunomodulatory molecules, which can potentially exacerbate OS-mediated neuronal damage, and neurodegeneration, their mechanism of action and mode of progression, are still obscure. Therefore, in this review, we have described the detailed role of OS and platelet in AD, addressing the therapeutic approach and molecular mechanism of platelet-mediated ROS generation as a contributing factor in aggravating the disease. � 2022 Elsevier Inc.Item Role of platelet in Parkinson's disease: Insights into pathophysiology & theranostic solutions(Elsevier Ireland Ltd, 2022-07-04T00:00:00) Beura, Samir Kumar; Panigrahi, Abhishek Ramachandra; Yadav, Pooja; Singh, Sunil KumarParkinson's disease (PD) is the second-most-common neurodegenerative disease characterized by motor and non-motor dysfunctions, which currently affects about 10 million people worldwide. Gradual death and progressive loss of dopaminergic neurons in the pars compacta region of substantia nigra result in striatal dopamine deficiency in PD. Specific mutation with further aggregation of ??synuclein in the intraneuronal inclusion bodies is considered the neuropathological hallmark of this disease. PD is often associated with various organelle dysfunctions inside a dopaminergic neuron, including mitochondrial damage, proteasomal impairment, and production of reactive oxygen species, thus causing subsequent neuronal death. Apart from several genetic and non-genetic risk factors, emerging research establishes an association between cardiovascular diseases, including coronary heart disease, myocardial infarction, congestive heart failure, and ischemic stroke with PD. The majority of these cardiovascular diseases have an origin from atherosclerosis, where endothelial dysfunction following thrombus formation is significantly regulated by blood platelet. This non-nucleated cell fragment expresses not only neuron-specific molecules and receptors but also several PD-specific biomarkers such as ?-synuclein, parkin, PTEN-induced kinase-1, tyrosine hydroxylase, dopamine transporter, thus making platelet a suitable peripheral model for PD. Besides its similarity with a dopaminergic neuron, platelet structural alterations, as well as functional abnormalities, are also evident in PD. However, the molecular mechanism behind platelet dysfunction is still elusive and quite controversial. This state-of-the-art review describes the detailed mechanism of platelet impairment in PD, addressing the novel platelet-associated therapeutic drug candidates for plausible PD management. � 2022 Elsevier B.V.Item Understanding Mutations in Human SARS-CoV-2 Spike Glycoprotein: A Systematic Review & Meta-Analysis(MDPI, 2023-03-28T00:00:00) Kumar, Reetesh; Srivastava, Yogesh; Muthuramalingam, Pandiyan; Singh, Sunil Kumar; Verma, Geetika; Tiwari, Savitri; Tandel, Nikunj; Beura, Samir Kumar; Panigrahi, Abhishek Ramachandra; Maji, Somnath; Sharma, Prakriti; Rai, Pankaj Kumar; Prajapati, Dinesh Kumar; Shin, Hyunsuk; Tyagi, Rajeev K.Genetic variant(s) of concern (VoC) of SARS-CoV-2 have been emerging worldwide due to mutations in the gene encoding spike glycoprotein. We performed comprehensive analyses of spike protein mutations in the significant variant clade of SARS-CoV-2, using the data available on the Nextstrain server. We selected various mutations, namely, A222V, N439K, N501Y, L452R, Y453F, E484K, K417N, T478K, L981F, L212I, N856K, T547K, G496S, and Y369C for this study. These mutations were chosen based on their global entropic score, emergence, spread, transmission, and their location in the spike receptor binding domain (RBD). The relative abundance of these mutations was mapped with global mutation D614G as a reference. Our analyses suggest the rapid emergence of newer global mutations alongside D614G, as reported during the recent waves of COVID-19 in various parts of the world. These mutations could be instrumentally imperative for the transmission, infectivity, virulence, and host immune system�s evasion of SARS-CoV-2. The probable impact of these mutations on vaccine effectiveness, antigenic diversity, antibody interactions, protein stability, RBD flexibility, and accessibility to human cell receptor ACE2 was studied in silico. Overall, the present study can help researchers to design the next generation of vaccines and biotherapeutics to combat COVID-19 infection. � 2023 by the authors.Item Unveiling the mechanism of platelet dysfunction in Parkinson's disease: The effect of 6-hydroxydopamine on human blood platelets(Elsevier Ltd, 2023-05-22T00:00:00) Beura, Samir Kumar; Yadav, Pooja; Panigrahi, Abhishek Ramachandra; Singh, Sunil KumarIntroduction: Parkinson's disease (PD) is a progressive neuronal illness often linked to increased cardiovascular complications, such as myocardial infarction, cardiomyopathy, congestive heart failure, and coronary heart disease. Platelets, which are the essential components of circulating blood, are considered potential players in regulating these complications, as platelet dysfunction is evident in PD. These tiny blood cell fragments are supposed to play a crucial role in these complications, but the underlying molecular processes are still obscure. Methods: To gain a better understanding of platelet dysfunction in PD, we investigated the impact of 6-hydroxydopamine (6-OHDA), an analog of dopamine that simulates PD by destroying dopaminergic neurons, on human blood platelets. The levels of intraplatelet reactive oxygen species (ROS) were assessed using H2DCF-DA (20 ?M), while mitochondrial ROS was evaluated using MitoSOX� Red (5 ?M), and intracellular Ca2+ was measured with Fluo-4-AM (5 ?M). The data were acquired through the use of both a multimode plate reader and a laser-scanning confocal microscope. Results: Our findings showed that 6-OHDA treatment increased the production of ROS in human blood platelets. The increase in ROS was confirmed by the ROS scavenger, NAC, and was also reduced by inhibiting the NOX enzyme with apocynin. Additionally, 6-OHDA potentiated mitochondrial ROS production in platelets. Furthermore, 6-OHDA triggered the intraplatelet Ca2+ elevation. This effect was mitigated by the Ca2+ chelator BAPTA, which decreased the ROS production triggered by 6-OHDA in human blood platelets, while the IP3 receptor blocker, 2-APB, reduced the formation of ROS induced by 6-OHDA. Conclusion: Our findings suggest that the 6-OHDA-induced ROS production is regulated by the IP3 receptor-Ca2+-NOX signaling axis in human blood platelets, where the platelet mitochondria also play a significant role. This observation provides a crucial mechanistic understanding of the altered platelet activities that are commonly observed in PD patients. � 2023 Elsevier Ltd