Identification of natural compounds (proanthocyanidin and rhapontin) as high-affinity inhibitors of SARS-CoV-2 Mpro and PLpro using computational strategies.

Introduction: The emergence of a new and highly pathogenic coronavirus (SARS-CoV-2) in Wuhan (China) and its spread worldwide has resulted in enormous social and economic losses. Amongst many proteins encoded by the SARS-CoV-2 genome, the main protease (Mpro) or chymotrypsin-like cysteine protease (3CLpro) and papain-like protease (PLpro) serve as attractive drug targets. Material and methods: We screened a library of 2267 natural compounds against Mpro and PLpro using high throughput virtual screening (HTVS). Fifty top-scoring compounds against each protein in HTVS were further evaluated by standard-precision (SP) docking. Compounds with SP docking energy of ≤ -8.0 kcal/mol against Mpro and ≤ -5.0 kcal/mol against PLpro were subjected to extra-precision (XP) docking. Finally, six compounds against each target proteins were identified and subjected to Prime/MM-GBSA free energy calculations. Compounds with the lowest Prime/MM-GBSA energy were subjected to molecular dynamics simulation to evaluate the stability of protein-ligand complexes. Results: Proanthocyanidin and rhapontin were identified as the most potent inhibitors of Mpro and PLpro, respectively. Analysis of protein-inhibitor interaction revealed that both protein-inhibitor complexes were stabilized by hydrogen bonding and hydrophobic interactions. Proanthocyanidin interacted with the catalytic residues (His41 and Cys145) of Mpro, while rhapontin contacted the active site residues (Trp106, His272, Asp286) of PLpro. The docking energies of proanthocyanidin and rhapontin towards their respective targets were -10.566 and -10.022 kcal/mol. Conclusions: This study's outcome may support application of proanthocyanidin and rhapontin as a scaffold to build more potent inhibitors with desirable drug-like properties. However, it requires further validation by in vitro and in vivo studies.

Potential of siRNA-Bearing Subtilosomes in the Treatment of Diethylnitrosamine-Induced Hepatocellular Carcinoma.

Therapeutics, based on small interfering RNA (siRNA), have demonstrated tremendous potential for treating cancer. However, issues such as non-specific targeting, premature degradation, and the intrinsic toxicity of the siRNA, have to be solved before they are ready for use in translational medicines. To address these challenges, nanotechnology-based tools might help to shield siRNA and ensure its specific delivery to the target site. Besides playing a crucial role in prostaglandin synthesis, the cyclo-oxygenase-2 (COX-2) enzyme has been reported to mediate carcinogenesis in various types of cancer, including hepatocellular carcinoma (HCC). We encapsulated COX-2-specific siRNA in Bacillus subtilis membrane lipid-based liposomes (subtilosomes) and evaluated their potential in the treatment of diethylnitrosamine (DEN)-induced hepatocellular carcinoma. Our findings suggested that the subtilosome-based formulation was stable, releasing COX-2 siRNA in a sustained manner, and has the potential to abruptly release encapsulated material at acidic pH. The fusogenic property of subtilosomes was revealed by FRET, fluorescence dequenching, content-mixing assay, etc. The subtilosome-based siRNA formulation was successful in inhibiting TNF-α expression in the experimental animals. The apoptosis study indicated that the subtilosomized siRNA inhibits DEN-induced carcinogenesis more effectively than free siRNA. The as-developed formulation also suppressed COX-2 expression, which in turn up-regulated the expression of wild-type p53 and Bax on one hand and down-regulated Bcl-2 expression on the other. The survival data established the increased efficacy of subtilosome-encapsulated COX-2 siRNA against hepatocellular carcinoma.

Amphotericin B Nano-Assemblies Circumvent Intrinsic Toxicity and Ensure Superior Protection in Experimental Visceral Leishmaniasis with Feeble Toxic Manifestation.

In spite of its high effectiveness in the treatment of both leishmaniasis as well as a range of fungal infections, the free form of the polyene antibiotic amphotericin B (AmB) does not entertain the status of the most preferred drug of choice in clinical settings. The high intrinsic toxicity of the principal drug could be considered the main impedance in the frequent medicinal use of this otherwise very effective antimicrobial agent. Taking into consideration this fact, the pharma industry has introduced many novel dosage forms of AmB to alleviate its toxicity issues. However, the limited production, high cost, requirement for a strict cold chain, and need for parenteral administration are some of the limitations that explicitly compel professionals to look for the development of an alternate dosage form of this important drug. Considering the fact that the nano-size dimensions of drug formulation play an important role in increasing the efficacy of the core drug, we employed a green method for the development of nano-assemblies of AmB (AmB-NA). The as-synthesized AmB-NA manifests desirable pharmacokinetics in the treated animals. The possible mechanistic insight suggested that as-synthesized AmB-NA induces necrosis-mediated cell death and severe mitochondrial dysfunction in L. donovani promastigotes by triggering depolarization of mitochondrial membrane potential. In vivo studies demonstrate a noticeable decline in parasite burden in the spleen, liver, and bone marrow of the experimental BALB/c mice host. In addition to successfully suppressing the Leishmania donovani, the as-formed AmB-NA formulation also modulates the host immune system with predominant Th1 polarization, a key immune defender that facilitates the killing of the intracellular parasite.

Crosstalk between SARS-CoV-2 Infection and Neurological Disorders: A Review.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent responsible for coronavirus disease (COVID-19), is an issue of global concern since March 2020. The respiratory manifestations of COVID-19 have widely been explained in the last couple of months of the pandemic. Initially, the virus was thought to be restricted to the pulmonary system; however, as time progressed and cases increased during the second wave of COVID-19, the virus affected other organs, including the nervous system. The neurological implication of SARS-CoV-2 infection is mounting, as substantiated by various reports, and in the majority of COVID-19 patients with neurological symptoms, the penetration of SARS-CoV-2 in the central nervous system (CNS) is likely. SARS-CoV-2 can enter the nervous system by exploiting the routes of olfactory mucosa, olfactory and sensory nerve endings, or endothelial and nerve tissues, thus crossing the neural-mucosal interface in the olfactory mucosa in the nose. Owing to multifactorial and complex pathogenic mechanisms, COVID-19 adds a large-scale risk to the entire nervous system. A thorough understanding of SARSCoV- 2 neurological damage is still vague; however, our comprehension of the virus is rapidly developing. The present comprehensive review will gain insights and provide neurological dimensions of COVID-19 and their associated anomalies. The review presents the entry routes of SARS-CoV-2 into the CNS to ascertain potential targets in the tissues owing to infection. We also discuss the molecular mechanisms involved, the array of clinical symptoms, and various nervous system diseases following the attack of SARS-CoV-2.

miRNAs in SARS-CoV-2 Infection: An Update.

Coronavirus disease-2019 (COVID-19) is a highly infectious disease caused by newly discovered severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the inception of SARS-CoV-2 in Wuhan, China, the virus has traveled more than 200 countries globally. The role of SARS-CoV-2 in COVID-19 has been thoroughly investigated and reviewed in the last 22 months or so; however, a comprehensive outline of miRNAs in SARS-CoV- 2 infection is still missing. The genetic material of SARS-CoV-2 is a single-stranded RNA molecule nearly 29 kb in size. RNA is composed of numerous sub-constituents RNA is found in the cells in a number of forms. including microRNAs (miRNAs). miRNAs play an essential role in biological processes like apoptosis, cellular metabolism, cell death, cell movement, oncogenesis, intracellular signaling, immunity, and infection. Lately, miRNAs have been involved in SARS-CoV-2 infection, though the clear demonstration of miRNAs in the SARS-CoV-2 infection is not fully elucidated. The present review article summarizes recent findings of miRNAs associated with SARS-CoV-2 infection. We presented various facets of miRNAs. miRNAs as the protagonists in viral infection, the occurrence of miRNA in cellular receptors, expression of miRNAs in multiple diseases, miRNA as a biomarker, and miRNA as a therapeutic tool have been discussed in detail. We also presented the vaccine status available in various countries.

Crosstalk between SARS-CoV-2 Infection and Type II Diabetes.

Since the outbreak of coronavirus disease (COVID-19) in Wuhan, China, triggered by severe acute respiratory coronavirus 2 (SARS-CoV-2) in late November 2019, spreading to more than 200 countries of the world, the ensuing pandemic to an enormous loss of lives, mainly the older population with comorbidities, like diabetes, cardiovascular disease, chronic obstructive pulmonary disease, obesity, and hypertension. Amongst these immune-debilitating diseases, SARS-CoV-2 infection is the most common in patients with diabetes due to the absence of a normal active immune system to fight the COVID-19. Recovery of patients having a history of diabetes from COVID-19 encounters several complications, and their management becomes cumbersome. For control of coronavirus, antiviral medications, glucose-lowering agents, and steroids have been carefully evaluated. In the present review, we discuss the crosstalk between SARS-CoV-2 infection and patients with a history of diabetes. We mainly emphasize the molecular factors that are involved in diabetic individuals recently infected by SARS-CoV-2 and developed COVID-19 disease. Lastly, we examine the medications available for the long-term management of diabetic patients with SARS-CoV-2 infection.

Mucormycosis and COVID-19 pandemic: Clinical and diagnostic approach.

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is yet to be controlled worldwide, especially in India. The second wave of coronavirus disease 2019 (COVID-19) led to panic and confusion in India, owing to the overwhelming number of the population that fell prey to this highly infectious virus of recent times. In the second wave of COVID-19, the patients had to fight both the virus and opportunistic infections triggered by fungi and bacteria. Repeated use of steroids, antibiotics, and oxygen masks during the management of severely and critically ill COVID-19 patients nurtured opportunistic infections such as mucormycosis. Despite mucormycosis being a decades-old disease, it has gained notice of its widespread occurrence in COVID-19 patients throughout India. Instances of mucormycosis are usually unearthed in immunocompromised individuals and are caused by the inhalation of filamentous fungi, either from the natural environment or through supportive care units. In the recent outbreak during the second wave of COVID-19 in India, it has been seen to cause secondary infection as it grows along with the treatment of COVID-19. Furthermore, COVID-19 patients with comorbidities such as diabetes were more likely to have the mucormycosis co-infection because of their challenged immune systems' inability to fight it. Despite the hype, mucormycosis still remains neglected and least studied, which is predominantly due to all focus on diagnostics, vaccine, and therapeutic research. In this review, we emphasize mainly on the association of mucormycosis in COVID-19 patients. We also present the molecular mechanism of mucormycosis for a better understanding of the fungal infections in patients who have recently been infected with SARS-CoV-2. Better understanding of fungal pathogens, immediate diagnosis, and management of the infections are crucial in COVID-19 patients, as high mortalities have been recorded in co-infected patients despite recovery from COVID-19.

Nucleotide Pool Imbalance and Antibody Gene Diversification.

The availability and adequate balance of deoxyribonucleoside triphosphate (dNTP) is an important determinant of both the fidelity and the processivity of DNA polymerases. Therefore, maintaining an optimal balance of the dNTP pool is critical for genomic stability in replicating and quiescent cells. Since DNA synthesis is required not only in genomic replication but also in DNA damage repair and recombination, the abnormalities in the dNTP pool affect a wide range of chromosomal activities. The generation of antibody diversity relies on antigen-independent V(D)J recombination, as well as antigen-dependent somatic hypermutation and class switch recombination. These processes involve diverse sets of DNA polymerases, which are affected by the dNTP pool imbalances. This review discusses the role of the optimal dNTP pool balance in the diversification of antibody encoding genes.

Synopsis of Pharmotechnological Approaches in Diagnostic and Management Strategies for Fighting Against COVID-19.

Nanoparticles (NPs) are projected to play a significant role in the fight against coronavirus disease (COVID-19). The various properties of NPs like magnetic and optical can be exploited to build diagnostic test kits. The unembellished morphological and physiochemical resemblances of SARS-CoV-2 with synthetic NPs make them a potent tool for mediation. Nanoparticles can be analytically functionalized with different proteins, polymers, and functional groups to perform specific inhibitory functions, while also serving as delivery vehicles. Moreover, NPs can also be employed to prepare broad-spectrum respiratory drugs and vaccines that can guard seasonal flu and prepare the human race for the pandemic in the future. The present review outlines the role of NPs for detection, diagnostic and therapeutic purposes against members of the coronavirus family. We emphasize nanomaterial-based approaches to address coronaviruses in general and SARS-CoV-2 in particular. We discuss NPs based detection systems like graphene (G-FET), biosensors, and plasmonic photothermal associated sensors. The therapeutic approaches exploiting NPs such as inorganic, organic virus-like & self-assembly protein (VLP), and inactivation of SARS-CoV-2 employing photodynamic are also presented.

GPCRs: The most promiscuous druggable receptor of the mankind.

All physiological events in living organisms originated as specific chemical/biochemical signals on the cell surface and transmitted into the cytoplasm. This signal is translated within milliseconds-hours to a specific and unique order required to maintain optimum performance and homeostasis of living organisms. Examples of daily biological functions include neuronal communication and neurotransmission in the process of learning and memory, secretion (hormones, sweat, and saliva), muscle contraction, cellular growth, differentiation and migration during wound healing, and immunity to fight infections. Among the different transducers for such life-dependent signals is the large family of G protein-coupled receptors (GPCRs). GPCRs constitute roughly 800 genes, corresponding to 2% of the human genome. While GPCRs control a plethora of pathophysiological disorders, only approximately one-third of GPCR families have been deorphanized and characterized. Recent drug data show that around 40% of the recommended drugs available in the market target mainly GPCRs. In this review, we presented how such system signals, either through G protein or via other players, independent of G protein, function within the biological system. We also discussed drugs in the market or clinical trials targeting mainly GPCRs in various diseases, including cancer.

Antiviral potential of some novel structural analogs of standard drugs repurposed for the treatment of COVID-19.

SARS-CoV-2 pandemic has claimed millions of lives across the world. As of June 2020, there is no FDA approved antiviral therapy to eradicate this dreadful virus. In this study, drug re-purposing and computational approaches were employed to identify high affinity inhibitors of SARS-CoV-2 Main protease (3CLpro), Papain-like protease (PLpro) and the receptor domain of Spike protein. Molecular docking on 40 derivatives of standard drugs (Remdesivir, Lopinavir and Theophylline) led to the identification of R10, R2 and L9 as potential inhibitors of 3CLpro, PLpro and Spike protein, respectively. The binding affinity of R10, R2 and L9 towards 3CLpro, PLpro and Spike protein were 4.03 × 106, 3.72 × 104 and 1.31 × 104M-1, respectively. These inhibitors interact with the active site or catalytic amino acid residues of 3CLpro, PLpro and Spike protein. We also examined the stability and dynamic behavior of protein-inhibitor complex by employing molecular dynamics simulation. RMSDs, RMSFs and variation in secondary structure of target proteins alone or in complex with their respective inhibitors were used to ascertain the integrity of proteins' structure during simulation. Moreover, physicochemical and ADMET properties of R10, R2 and L9 along with Remdesivir, Lopinavir and Theophylline were determined. In vitro and In vivo studies are needed to further validate the potential of these derivatives before they can be developed into potential drug molecules.Communicated by Ramaswamy H. Sarma.

Frontier View on Nanotechnological Strategies for Neuro-therapy.

BACKGROUND: Nanotechnology exploits materials and devices with a functional organization that has been engineered at the nanometre scale. The application of nanotechnology in neuroscience involves specific interactions with neurons and glial cells. This property is used for delivering drugs and other small molecules (such as genes, oligonucleotides and contrasting agents) across the blood brain barrier (BBB), an important requirement for delivering the drug successfully to the brain. OBJECTIVE: Nanotechnology based approaches (NBA) favours transcytosis-mediated delivery of nanoparticles to the brain by crossing the BBB. The last five years have witnessed the successful applications of NBA to treat neurological disorders. It is expected that the development of novel NBA will result in important insights on the brain mechanisms, and eventually provide better medical care to patients suffering from neurological disorders. CONCLUSION: This review introduces the emerging work in this area and summarizes the successful NBA used in recent past for treating various neurological disorders ike Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, meningitis and glioblastoma.

Relationship between CNS and Immunology: Correlation with Psychology.

BACKGROUND: Higher animals, especially the human beings have the privilege of employing advanced central nervous system (CNS) as well as the evolved immune system to ward off various onslaughts throughout their life. Alterations in inflammatory and neural regulatory pathways lead to several disorders that are now becoming the cause of concern across the world. Deregulation in bidirectional network, particularly in aging population, leads to several neurodegenerative diseases such as dementia as a one of the major characteristics. OBJECTIVE: Interestingly, research updates have signified the role of abrupt immune regulation in several brain diseases, establishing a link between altered immune system and CNS related diseases. In the later period of life, the altered immune response in the pathogenesis of major psychiatric disorders, has become more visible. In the present manuscript, we present a synopsis on the linkage of CNS and immune system with respect to psychology, with the aim to further understand the biological machinery of psychoneuroimmunological disorders. The immune system of human being plays an important role in keeping pathogen onslaughts on bay. CONCLUSION: Our manuscript concludes a close relationship between emotion and psychology to diseases and immunology, proclaiming the need of providing enhanced attention on mechanistic aspect of psychoneuroimmunological disorders.

PeMtb: A Database of MHC Antigenic Peptide of Mycobacterium tuberculosis.

BACKGROUND: For design of a subunit vaccine for tuberculosis, identification of antigenic Tcell epitope is of utmost importance. Several MHC prediction server are available that can accurately predict antigenic peptide of variable lengths. However, peptides predicted from one server not necessarily are predicted form another server, thus creating a confusing situation for scientists to choose a best epitope. METHOD: Keeping the above problem in mind, we developed a comprehensive database of peptides of Mycobacterial proteins. Each protein was taken from PubMed and was run through different MHC prediction servers, with the results being compiled into one database. RESULTS: For each protein, PeMtb generates a set of three different mers of variable lengths (12 mer or 13-mer) based on their ranking; with each mer being predicted for a plethora of MHC alleles. Researcher can choose the peptide (mers) that gives best binding affinity from most of the servers. CONCLUSION: The database relieves the investigators of the painstaking task of searching various MHC prediction servers for the right epitope (T-cell epitope) for a particular Mycobacterial antigen. We trust and anticipate that PeMtb will be a practical platform for trial and computational analyses of antigenic peptides for Mycobacterium tuberculosis. All the resources and information can be accessed by PeMtb home page www.pemtb-amu.org.

Nanoparticle-Based Mycosis Vaccine.

Many diseases that were considered major affliction of mankind in the past have been successfully eradicated with introduction of appropriate vaccine strategies. In order to expedite new challenges coming up to deal with various infectious diseases, nano-particulate-based subunit vaccines seem to be the demand of ordeal. The nano-vaccines can find better scope for the diseases that were not rampant in the semi-advanced world few years back. For example in present-day circumstances that corroborate with advancement in the field of medical sciences in terms of cancer chemotherapy, organ transplantation, therapy of autoimmune diseases, etc.; along with prevalence of altogether unheard diseases such as HIV infection, people are at risk of infliction with many more pathogens. In this regard, development of an effective prophylactic strategy against many opportunistic infections primarily caused by fungal pathogens needs better understanding of host pathogen relation and role of active immunity against pathogenic fungi. In the present study, we have tried to decipher effectiveness of a nano-sized vaccine delivery system in imparting protection against fungal pathogens.

Recent advances in the development of novel protein scaffolds based therapeutics.

Antibodies occupy a central position when it comes to binding proteins with desired antigenic specificities. During the past decade, a plethora of recombinant or humanized versions of antibodies have entered clinical settings with outstanding accomplishments. Yet, they suffer from several drawbacks such as high molecular weight, limited tissue penetration, instability, high production cost, requirement for large doses and potential cytotoxicity. As a result, new generation of receptor proteins has been developed, that are derived from small and robust immunoglobulin (Ig) or non-immunoglobulin based "scaffolds". Combinatorial protein engineering has tremendous scope in the development of these protein scaffolds with immunoglobulin like specificity and/or prescribed binding functions. The advancement made in this regard can boast of developing various validated Ig based and non-Ig protein scaffolds with desirable therapeutic potential. The newly emerging technology has profound scope in translational biology and offer matching replacement for existing immunotherapeutic agents. Only few data from early clinical studies are available yet, but many more are likely to come in the near future. Here, we provide a glimpse of recent clinical advances in the field of existing protein scaffolds.

Recent Updates on Molecular Genetic Engineering Approaches and Applications of Human Therapeutic Proteins.

Therapeutic proteins are engineered proteins produced in the laboratory for pharmaceutical use. With the advent of recombinant DNA technology, the proteins can be generated in specific host cells under defined conditions. In the process of production of genetically engineered animals, the gene of interest can be added at a single cell stage to produce a cloned animal from genetically engineered cells. Several recombinant cytokines, clotting factors etc have been licensed and are currently being utilized for the treatment of cancer, infectious diseases, hemophilia, anemia, multiple sclerosis, and hepatitis B/C. Therapeutic proteins that are useful for human are successfully produced in poultry as well as in livestock animals. However, the fastest growing class of therapeutic proteins are antibodies especially monoclonal antibodies (mAb), the most important class of therapeutic protein with the potential to generate significant revolution in terms of clinical success rate. Here, we review the most recent clinical advances in the field of emerging and existing therapeutic proteins.

TLR Agonist Augments Prophylactic Potential of Acid Inducible Antigen Rv3203 against Mycobacterium tuberculosis H37Rv in Experimental Animals.

In general, the members of Lip gene family of Mycobacterium tuberculosis evoke strong immune response in the host. Keeping this fact into consideration, we investigated role of Rv3203, a cell wall associated protein with lipolytic activity, in imparting protection against experimental murine tuberculosis. The data of the present study suggested that archaeosome encapsulated Rv3203 induce strong lymphocyte proliferation, up-regulated Th-1 biased cytokines profile, increased expression of co-stimulatory markers on both antigen presenting cells and T lymphocytes. The immuno-prophylactic response was further modulated by exposure of the animals to zymosan, a TLR2/6 agonist, prior to immunization with archaeosome encapsulated Rv3203. Interestingly, pre-treatment of experimental animals with zymosan boosted strong immunological memory as compared to archaeosome encapsulated Rv3203 as well as BCG vaccine. We conclude that priming of immunized animal with TLR agonist followed by immunization with archaeosomes encapsulated Rv3203 offer substantial protection against tuberculosis infection and could be a potential subunit vaccine based prophylactic strategy.

Super aggregated form of Amphotericin B: a novel way to increase its therapeutic index.

Amphotericin B (AmB)-deoxycholate micellar formulation, Fungizone®, is the drug of choice for the treatment of unidentified mycotic infections. However, it usage has been marred by long therapeutic regimes and severe side effects. The less toxic lipid associated AmB formulations have been limited by their high expense, with some loss in activity. The quest for decreasing AmB cytotoxicity as well as production cost has resulted in the development of AmB super-aggregate as an alternative to its existing lipid formulations. AmB super-aggregate is spectroscopically distinct from the aggregate present in Fungizone, displaying enhanced thermodynamic stability. The poly-aggregated form of AmB exhibits reduced toxicity in mammalian cells in vitro and to mice in vivo, while maintaining its 'gold standard' antifungal activity. Poly-aggregated AmB interacts predominantly with serum albumin and also attenuates its ability to induce potentially harmful cytokines. Bio-distribution studies have demonstrated that the self-associated AmB shows greater accumulation in reticulo-endothelial organs while sparing kidney, one of the principal organs where its toxic effects are seen. The super-aggregated AmB can thus be used to improve the therapeutic index of AmB against a plethora of fungal infections including candidiasis and cryptococcosis, thus providing a fitting solution to growing demand of an active, less toxic substitute of AmB.

Oxidized antithrombin is a dual inhibitor of coagulation and angiogenesis: Importance of low heparin affinity.

Endogenous proteins that promote vascular endothelial cell based inhibition of angiogenesis are an attractive option for antitumor therapy. Inactive cleaved and latent conformations of antithrombin (AT) are antiangiogenic, but not its native form which is an inhibitor of proteases involved in blood coagulation. Unlike native, the cleaved and latent conformations are reactive center loop inserted conformations which binds heparin with very low affinity. We use a sulfoxy modified AT to assess the role of reactive center loop insertion and heparin affinity in antiangiogenic function. Chorioallantoic membrane assay (CAM) shows that antiangiogenic activity of latent and oxidized AT are better than thalidomide, a potent antiangiogenic drug. Wound healing experiments suggest that latent and oxidized conformations can influence endothelial cell migration. Latent and cleaved conformations of AT shows an increase in α-helical content in the presence of unfractionated heparin, but not the oxidized AT. Unlike the loop inserted polymer, cleaved and latent conformations, oxidized AT has factor Xa inhibitory activity indicating that loop insertion is not necessary for antiangiogenic role. The results of our study establish that active conformation of AT can become antiangiogenic while maintaining its anticoagulant activity possibly through chelation of low affinity heparin in the vicinity of endothelial cell.