Arsenic album 30C exhibits crystalline nano structure of arsenic trioxide and modulates innate immune markers in murine macrophage cell lines.

Macrophages are associated with innate immune response and M1-polarized macrophages exhibit pro-inflammatory functions. Nanoparticles of natural or synthetic compounds are potential triggers of innate immunity. As2O3 is the major component of the homeopathic drug, Arsenic album 30C.This has been claimed to have immune-boosting activities, however, has not been validated experimentally. Here we elucidated the underlying mechanism of Ars. alb 30C-mediated immune priming in murine macrophage cell line. Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD) used for the structural analysis of the drug reveals the presence of crystalline As2O3 nanoparticles of cubic structure. Similarly, signatures of M1-macrophage polarization were observed by surface enhanced Raman scattering (SERS) in RAW 264.7 cells with concomitant over expression of M1 cell surface marker, CD80 and transcription factor, NF-κB, respectively. We also observed a significant increase in pro-inflammatory cytokines like iNOS, TNF-α, IL-6, and COX-2 expression with unaltered ROS and apoptosis in drug-treated cells. Enhanced expression of Toll-like receptors 3 and 7 were observed both in transcriptional and translational levels after the drug treatment. In sum, our findings for the first time indicated the presence of crystalline As2O3 cubic nanostructure in Ars. alb 30C which facilitates modulation of innate immunity by activating macrophage polarization.

Crystal structure of the N-terminal domain of MtClpC1 in complex with the anti-mycobacterial natural peptide Lassomycin.

Antibiotics form our frontline therapy against disease-causing bacteria. Unfortunately, antibiotic resistance is becoming more common, threatening a future where these medications can no longer cure infections. Furthermore, the emergence of multidrug-resistant (MDR), totally drug-resistant (TDR), and extensively drug-resistant (XDR) tuberculosis has increased the urgency of discovering new therapeutic leads with unique modes of action. Some natural peptides derived from actinomycetes, such as Cyclomarin A, Lassomycin, Rufomycin I, and Ecumicin, have potent and specific bactericidal activity against Mycobacterium tuberculosis, with the specificity owing to the fact that these peptides target the ClpC1 ATPase, an essential enzyme in mycobacteria, and inhibit/activate the proteolytic activity of the ClpC1/P1/P2 complex that participates in protein homeostasis. Here, we report the high-resolution crystal structure of the N-terminal domain of ClpC1 (ClpC1 NTD) in complex with Lassomycin, showing the specific binding mode of Lassomycin. In addition, the work also compares the Lassomycin complex structure with the previously known structures of ClpC1 NTD in complex with other natural peptides such as Cyclomarin A, Rufomycin I, and Ecumicin.

Thermodynamics of benzoquinone-induced conformational changes in nucleic acids and human serum albumin.

Biological macromolecules such as proteins, nucleic acids, carbohydrates and lipids, play a crucial role in biochemical and molecular processes. Thus, the study of the structure-function relationship of biomolecules in presence of ligands is an important aspect of structural biology. The current communication describes the chemico-biological interaction between benzene metabolite para-benzoquinone (BQ) with B-form of nucleic acids (B-DNA) and human serum albumin (HSA). The binding ability of HSA towards bromocresol green (BCG) was significantly suppressed when exposed to increasing concentrations of BQ in the presence of various physiological buffers. Further, the native fluorescence of HSA was drastically reduced and the secondary structures of HSA were significantly compromised with increasing concentrations of BQ. In vitro and in silico studies also revealed that BQ binds to domains I and II of HSA and thus altering the conformation of HSA which may potentially affect plasma osmotic pressure, as well as the binding and transport of numerous endogenous and exogenous molecules. Similarly, BQ interacts directly to the GC region of B-DNA particularly in the minor groove which was also assessed by computational docking studies. Isothermal titration calorimetry data suggest higher binding affinity of BQ towards DNA than HSA. Various spectroscopic observations also suggest that BQ binds to DNA preferably in the minor grooves. Thus, the results revealed that BQ may play a key role in inducing mutagenicity, either by formation of adducts on GC regions or by accelerating oxidative damage to biomacromolecules through chemico-biological interactions.

A Computational Insight on the Inhibitory Potential of 8-Hydroxydihydrosanguinarine (8-HDS), a Pyridone Containing Analog of Sanguinarine, against SARS CoV2.

The unprecedented global pandemic of COVID-19 has created a daunting scenario urging an immediate generation of therapeutic strategy. Interventions to curb the spread of viral infection primarily include setting targets against the virus. Here in this study we target S protein to obstruct the viral attachment and entry and also the M pro to prevent the viral replication. For this purpose, the interaction of S protein and M pro with phytocompounds, sanguinarine and eugenol, and their derivatives were studied using computational tools. Docking studies gave evidence that 8-hydroxydihydrosanguinarine (8-HDS), a derivative of sanguinarine, showed maximum binding affinity with both the targets. The binding energies of the ligand with S protein and M pro scored to be ΔGb -9.4 Kcal/mol and ΔGb -10.3 Kcal/mol, respectively. MD simulation studies depict that the phytocompound could effectively cause structural perturbations in the targets which would affect their functions. 8-Hydroxydihydrosanguinarine distorts the α-helix in the secondary structure of M pro and RBD site of S protein. Protein-protein interaction study in presence of 8-hydroxydihydrosanguinarine also corroborate the above findings which indicate that this polyphenol interferes in the coupling of S protein and ACE2. The alterations in protonation of M pro suggest that the protein structure undergoes significant structural changes at neutral pH. ADME property of 8-hydroxydihydrosanguinarine indicates this could be a potential drug. This makes the phyto-alkaloid a possible therapeutic molecule for anti COVID-19 drug design.

Epigenomic interplay in tumor heterogeneity: Potential of epidrugs as adjunct therapy.

"Heterogeneity" in tumor mass has immense importance in cancer progression and therapy. The impact of tumor heterogeneity is an emerging field and not yet fully explored. Tumor heterogeneity is mainly considered as intra-tumor heterogeneity and inter-tumor heterogeneity based on their origin. Intra-tumor heterogeneity refers to the discrepancy within the same cancer mass while inter-tumor heterogeneity refers to the discrepancy between different patients having the same tumor type. Both of these heterogeneity types lead to variation in the histopathological as well as clinical properties of the cancer mass which drives disease resistance towards therapeutic approaches. Cancer stem cells (CSCs) act as pinnacle progenitors for heterogeneity development along with various other genetic and epigenetic parameters that are regulating this process. In recent times epigenetic factors are one of the most studied parameters that drive oxidative stress pathways essential during cancer progression. These epigenetic changes are modulated by various epidrugs and have an impact on tumor heterogeneity. The present review summarizes various aspects of epigenetic regulation in the tumor microenvironment, oxidative stress, and progression towards tumor heterogeneity that creates complications during cancer treatment. This review also explores the possible role of epidrugs in regulating tumor heterogeneity and personalized therapy against drug resistance.

CTK7A, a curcumin derivative, can be a potential candidate for targeting HIF-1α/p300 complex: Evidences from in vitro and computational studies.

Hypoxia-inducible factor-1 (HIF-1) is a transcription factor which plays a critical role in several biochemical pathways, and consists of oxygen-dependent alpha (α) and a constitutively expressed beta (ß) subunit. Under hypoxic conditions, HIF-1α is stabilized and forms a complex with ß subunit and this complex is associated with cancer progression. HIF-1α activity is mainly regulated by its transcriptional co-activator p300 which has histone acetyl-transferase (HAT) activity. p300 HAT activity is very crucial for p300 auto-acetylation and subsequently its interaction with its partner molecule HIF-1α as well as proapoptotic protein p53. p300 is a multi-domain protein and CH1 domain of p300 is the interacting partner of the C-terminal domain (CTD) of HIF-1α as well as p53. Several p300 HAT inhibitors are reported to suppress p300 auto-acetylation which inhibits its interaction with associated partners. We demonstrated that the p300 HAT inhibitor CTK7A down-regulated p300 auto-acetylation, HIF-1α accumulation as well as activity in gastric cancer cell lines. Protein-protein interaction and molecular docking studies revealed a significant decrease in the binding energy of full-length p300 as well as p300-CH1 and HIF-1α-CTD complex in presence of CTK7A. Further, SwissADME, evaluates the drug-likeliness property of CTK7A by analyzing its lipophilicity, size, polarity, solubility, saturation, and flexibility. Our in vitro and in silico data support reduced HIF-1α-p300 interaction in the presence of CTK7A. Hence, CTK7A might be playing a crucial role in down-regulating HIF-1α activity and can be a prospective anticancer drug.

Therapeutic Potential and Ethnopharmacology of Dominant Mangroves of Bhitarkanika National Park, Odisha, India.

Bhitarkanika National Park is the second largest contiguous mangrove forest of India. Approximately 0.15 million mangrove depending population are found residing in and around 307 villages within the National Park. Despite being one of the most diverse mangrove habitations of India, the ethnopharmacological practices are meager in comparison to the other mangrove regions of India and Southeast Asia. The present review is aimed to congregate information on the therapeutic potential and ethnopharmacology of nine dominant mangrove species of the National Park, such as Aegiceras corniculatum, Avicenia marina, Avicenia officinalis, Ceriops decandra, Excoecaria agallocha, Heritiera fomes, Lumnitzera racemosa, Rhizophora mucronata, and Sonneratia apetala. Our aim is to generate social awareness among the mangrove dwellers to promote uses of folklore medicine using these tremendously potential mangrove plants, as a complementary step to strengthen community health. Further, we also want to grab the attention of researchers working in related disciplines, for their holistic and extensive studies towards bio-prospectation of the dominant mangrove plants of Bhitarkanika National Park.

Epigenetic signature in neural plasticity: the journey so far and journey ahead.

Neural plasticity is a remarkable characteristic of the brain which allows neurons to rewire their structure in response to internal and external stimuli. Many external stimuli collectively referred to as 'epigenetic factors' strongly influence structural and functional reorganization of the brain, thereby acting as a potential driver of neural plasticity. DNA methylation and demethylation, histone acetylation, and deacetylation are some of the frontline epigenetic mechanisms behind neural plasticity. Epigenetic signature molecules (mostly proteins) play a pivotal role in epigenetic reprogramming. Though neuro-epigenetics is an incredibly important field of emerging research, the critical role of signature proteins associated with epigenetic alteration and their involvement in neural plasticity needs further attention. This study gives an integrated and systematic overview of the current state of knowledge with a clear idea of types of neural plasticity and the context-dependent role of epigenetic signature molecules and their modulation by some natural bioactive compounds.

The modulatory role of prime identified compounds in Geophila repens in mitigating scopolamine-induced neurotoxicity in experimental rats of Alzheimer's disease via attenuation of cholinesterase, ß-secretase, MAPt levels and inhibition of oxidative stress imparts inflammation.

ETHNOPHARMACOLOGICAL RELEVANCE: Geophila repens (L.) I.M. Johnst (Rubiaceae) is a small perennial creeper native to India, China, and other countries in Southeast Asia. The hot decoction of leaves is used orally for memory enhancing by the local folk of Andhra Pradesh, India. The ethnomedicinal claim of G. repens as memory enhancer was initially studied by the authors. Results demonstrated the important antioxidant and anticholinesterase activities of isolated molecule Pentylcurcumene and bioactive hydroalcohol extract of leaves of G. repens (GRHA). AIM OF THE STUDY: Based on the previous findings, additional research is needed to examine the efficacy of GRHA for memory enhancing properties. We therefore investigated the modulatory role of prime identified compounds in GRHA in mitigating scopolamine-induced neurotoxicity in experimental rats of Alzheimer's disease (AD) via attenuation of cholinesterase, ß-secretase, MAPt levels and inhibition of oxidative stress imparts inflammation. METHODS: Scopolamine (3 mg/kg) induced experimental rats of AD were treated with GRHA (300, 400 mg/kg) for 14 days. During the experimental period, elevated T-maze and locomotion-activity were performed to assess learning and memory efficacy of GRHA. At the end of the experiment, biochemical, neurochemical, neuroinflammation and histopathological observation of brain cortex were examined. GC-MS/MS analysis reported 31 compounds, among them 8 bioactive compounds possess antioxidant, neuroinflammation, neuroprotective activities, and were considered for docking analysis towards cholinesterase, ß-secretase activities in AD. RESULTS: GRHA 400 significantly improved learning and memory impairment with the improvement of oxidative stress (MDA, SOD, GSH, CAT), DNA damage (8-OHdG), neurochemical (AChE, BuChE, BACE1, BACE2, MAPt), neuroinflammation (IL-6, TNF-α) markers in neurotoxic rats. Docking studies of 8 compounds demonstrated negative binding energies for cholinesterase and ß-secretase indicating high affinity for target enzymes in AD. Test results were corroborated by the improvement of cellular tissue architecture of brain cortex in AD rats. CONCLUSION: Synergistic action of genistin, quercetin-3-D-galactoside, 9,12,15-octadecatrienoic-acid methyl-ester, phytol, retinal, stigmasterol, n-hexadecanoic acid, ß-sitosterol in GRHA restores memory-deficits via attenuation of cholinesterase, ß-secretase, MAPt level and inhibition of oxidative-stress imparts inflammation in AD.

Factors regulating dynamics of angiotensin-converting enzyme-2 (ACE2), the gateway of SARS-CoV-2: Epigenetic modifications and therapeutic interventions by epidrugs.

Angiotensin-converting enzyme-2 (ACE2) is one of the major components of the renin-angiotensin system (RAS) and participates in the physiological functions of the cardiovascular system and lungs. Recent studies identified ACE2 as the receptor for the S-protein of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and thus acts as the gateway for viral entry into the human body. Virus infection causes an imbalance in the RAS axis and induces acute lungs injury and fibrosis. Various factors regulate ACE2 expression patterns as well as control its epigenetic status at both transcription and translational levels. This review is mainly focused on the impact of environmental toxicants, drugs, endocrine disruptors, and hypoxia as controlling parameters for ACE2 expression and its possible modulation by epigenetic changes which are marked by DNA methylation, histone modifications, and micro-RNAs (miRNAs) profile. Furthermore, we have emphasized on interventions of various phytochemicals and bioactive compounds as epidrugs that regulate ACE2-S-protein interaction and thereby curb viral infection. Since ACE2 is an important component of the RAAS axis and a crucial entry point of SARS-CoV-2, the dynamics of ACE2 expression in response to various extrinsic and intrinsic factors are of contemporary relevance. We have collated updated information on ACE2 expression modulated by epidrugs, and urge to take over further studies on these important physiological regulators to unravel many more systemic linkages related to both metabolic and infectious diseases, in general and SARS-CoV-2 in particular for further development of targeted interventions.

Interface-based design of the favipiravir-binding site in SARS-CoV-2 RNA-dependent RNA polymerase reveals mutations conferring resistance to chain termination.

Favipiravir is a broad-spectrum inhibitor of viral RNA-dependent RNA polymerase (RdRp) currently being used to manage COVID-19. Accumulation of mutations in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RdRp may facilitate antigenic drift, generating favipiravir resistance. Focussing on the chain-termination mechanism utilized by favipiravir, we used high-throughput interface-based protein design to generate > 100 000 designs of the favipiravir-binding site of RdRp and identify mutational hotspots. We identified several single-point mutants and designs having a sequence identity of 97%-98% with wild-type RdRp, suggesting that SARS-CoV-2 can develop favipiravir resistance with few mutations. Out of 134 mutations documented in the CoV-GLUE database, 63 specific mutations were already predicted as resistant in our calculations, thus attaining ˜ 47% correlation with the sequencing data. These findings improve our understanding of the potential signatures of adaptation in SARS-CoV-2 against favipiravir.

A primer on cytokines.

Cytokines are pleiotropic polypeptides that control the development of and responses mediated by immune cells. Cytokine classification predominantly relies on [1] the target receptor(s), [2] the primary structural features of the extracellular domains of their receptors, and [3] their receptor composition. Functionally, cytokines are either pro-inflammatory or anti-inflammatory, hematopoietic colony-stimulating factors, developmental and would healing maintaining immune homeostasis. When the balance in C can form complex networks amongst themselves that may affect the homeostasis and diseases. Cytokines can affect resistance and susceptibility for many diseases and their availability in the host cytokine production and interaction is disturbed, immunopathogenesis sets in. Therefore, cytokine-targeting bispecific, and chimeric antibodies form a significant mode of immnuo-therapeutics Although the field has grown deep and wide, many areas of cytokine biology remain unknown. Here, we have reviewed these cytokines along with the organization, signaling, and functions through respective cytokine-receptor-families. Being part of the special issue on the Role of Cytokines in Leishmaniasis, this review is intended to be used as an organized primer on cytokines and not a resource for detailed discussion- for which a two-volume Handbook of cytokines is available- on each of the cytokines. Priming the readers on cytokines, we next brief the role of cytokines in Leishmaniasis. In the brief, we do not provide an account of each of the involved cytokines known to date, instead, we offer a temporal relationship between the cytokines and the progress of the infection towards the alternate outcomes- healing or non-healing- of the infection.

Catechin and curcumin interact with S protein of SARS-CoV2 and ACE2 of human cell membrane: insights from computational studies.

The recent outbreak of the coronavirus (SARS-CoV2) is an unprecedented threat to human health and society across the globe. In this context, development of suitable interventions is the need of the hour. The viral spike protein (S Protein) and the cognate host cell receptor ACE2 can be considered as effective and appropriate targets for interventions. It is evident from the present computational study, that catechin and curcumin, not only exhibit strong binding affinity to viral S Protein and host receptor ACE2 but also to their complex (receptor-binding domain (RBD) of the spike protein of SARS-CoV2 and ACE2; RBD/ACE2-complex). The binding affinity values of catechin and curcumin for the S protein, ACE2 and RBD/ACE2-complex are - 10.5 and - 7.9 kcal/mol; - 8.9 and - 7.8 kcal/mol; and - 9.1 and - 7.6 kcal/mol, respectively. Curcumin directly binds to the receptor binding domain (RBD) of viral S Protein. Molecular simulation study over a period of 100 ns further substantiates that such interaction within RBD site of S Protein occurs during 40-100 ns out of 100 ns simulation trajectory. Contrary to this, catechin binds with amino acid residues present near the RBD site of S Protein and causes fluctuation in the amino acid residues of the RBD and its near proximity. Both catechin and curcumin bind the interface of 'RBD/ACE2-complex' and intervene in causing fluctuation of the alpha helices and beta-strands of the protein complex. Protein-protein interaction studies in presence of curcumin or catechin also corroborate the above findings suggesting the efficacy of these two polyphenols in hindering the formation of S Protein-ACE2 complex. In conclusion, this computational study for the first time predicts the possibility of above two polyphenols for therapeutic strategy against SARS-CoV2.

Recombinant expression, purification and SAXS analysis of Arabidopsis thaliana ClpC1.

Caseinolytic protease-associated chaperones (Clp chaperones) are HSP100 proteins belonging to the family of ATPases having diverse cellular functions, and they occur in various organisms ranging from bacteria to plants and mammals. Most Clp chaperones have a hexameric organization and associate with tetradecameric Clp proteases to recognize and unfold protein substrates that get degraded within the cellular milieu. Vascular plants have a diverse family of Clp chaperones compared to other organisms; wherein, the chloroplasts of Arabidopsis thaliana alone contain four distinct Clp chaperones, such as ClpC1, ClpC2, ClpD, and ClpB3. The paralogs AtClpC1 and AtClpC2 are more than 90% identical, though the extent of functional overlap between the two is not clear. Moreover, in vitro characterization reports are available only for AtClpC2, as AtClpC1 could not be expressed in recombinant form in the past. Herein, using a bacterial expression system, we have successfully expressed and purified AtClpC1 with a short N-terminal truncation, employing a three-step chromatographic purification strategy. We show that AtClpC1 exists as a hexamer in the presence of ATP and MgCl2, as known for other functional Clp chaperones. Further, our SAXS analyses provide a low-resolution envelope structure for the hexameric AtClpC1, which very well fits a ClpC hexamer model.

March of Mycobacterium: miRNAs intercept host cell CD40 signalling.

The disease tuberculosis is fatal if untreated. It is caused by the acid-fast bacilli Mycobacterium tuberculosis. Mycobacterium resides and replicates within the alveolar macrophages, causing inflammation and granuloma, wherein macrophage-T cell interactions enhance the inflammation-causing pulmonary caseous lesions. The first interactions between Mycobacterium and the receptors on macrophages decide the fate of Mycobacterium because of phagolysosomal impairments and the expression of several miRNAs, which may regulate CD40 expression on macrophages. While the altered phagolysosomal functions impede antigen presentation to the T cell-expressed antigen receptor, the interactions between the macrophage-expressed CD40 and the T cell-expressed CD40-ligand (CD40L or CD154) provide signals to T cells and Mycobacterium-infected macrophages. These two functions significantly influence the resolution or persistence of Mycobacterium infection. CD40 controls T-cell polarisation and host-protective immunity by eliciting interleukin-12p40, nitric oxide, reactive oxygen species and IFN-γ production. Indeed, CD40-deficient mice succumb to low-dose aerosol infection with Mycobacterium because of deficient interleukin (IL)-12 production leading to impaired IFN-γ-secreting T-cell response. In contrast, despite generating fewer granulomas, the CD40L-deficient mice developed anti-mycobacterial T-cell responses to the levels observed in the wild-type mice. These host-protective responses are significantly subdued by the Mycobacterium-infected macrophage produced TGF-ß and IL-10, which promote pro-mycobacterial T-cell responses. The CD40-CD40L-induced counteractive immune responses against Mycobacterium thus present a conundrum that we explain here with a reconciliatory hypothesis. Experimental validation of the hypothesis will provide a rationale for designing anti-tubercular immunotherapy.

First report on transferrin in the silkworm, Antheraea mylitta, with a putative role in antioxidant defense: Insights from proteomic analysis and immunodetection.

Transferrin is a highly conserved multifunctional protein involved in iron metabolism, oxidative stress and immune response. However, very little is known about its context-dependent functional role in insects. The present study adopts a proteomic approach to identify an abundant hemolymph protein of silkworm (Antheraea mylitta) as transferrin. SDS-PAGE coupled to LC-MS/MS was followed to identify this protein (75.7 kDa) in the advanced larvae of A. mylitta as transferrin (AmTsf). Antibody developed against this protein enabled us to determine its tissue-specific expression and functional relevance during development. Its immunodetection was optimized by western blotting, immunohisto- and cytochemistry in the larval and pupal tissues of this insect. AmTsf exhibited a considerable homology with that of other related insects. It was found to be expressed constitutively in hemolymph, fat body, midgut and silk gland of this insect during development. Abundance of transferrin in the hemolymph of this species and its upregulation in response to oxidant challenges indicated its tissue-specific role in the antioxidant protection. The present work adds to the existing knowledge of multiple roles of transferrin in insects and provides an insight into a relatively unexplored aspect of iron-associated H2O2 metabolism and redox homeostasis in the apparent absence of catalase and glutathione peroxidase. Therefore, A. mylitta can be an attractive acatalasemic model for the study of in vivo redox regulation. In addition, this study provides a novel hypothesis to explore the role of transferrin in limiting oxidative stress during larval rearing of silkworm.

Curcumin restores hepatic epigenetic changes in propylthiouracil(PTU)Induced hypothyroid male rats: A study on DNMTs, MBDs, GADD45a, C/EBP-ß and PCNA.

6-n-propyl-2-thiouracil (PTU), a thioamide drug, is used as an effective anti-thyroid agent to treat hyperthyroidism and Graves' disease. However, acute liver oxidative damage is an important side effect of the drug. In the present study, we report that PTU administration to rat induces hepatic epigenetic changes by upregulating expression of DNMT1, DNMT3a, DNMT3b, MBD4, MeCP2, p53 and Gadd45a and down-regulation of PCNA and C/EBP-ß. This is accompanied by decrease in the cell population and augmentation of cellular lipid peroxidation, an index of oxidative stress, in liver. On the other hand, co-administration of curcumin, a polyphenol extract from the rhizome of Curcuma longa L, along with PTU ameliorates PTU- induced oxidative stress and epigenetic parameters except for the expression of MBD4. Also, co-administration of curcumin with PTU resulted in restoration of hepatic cell population and histoarchitecture. The protective effect of curcumin to PTU-induced hepatotoxicity is attributed to its antioxidative properties.