VIRTUAL SCREENING STUDIES OF SEAWEED METABOLITES FOR PREDICTING POTENTIAL PPARγ AGONISTS

Objective: Peroxisome Proliferator-Activated Receptor-gamma (PPARγ) is a crucial nuclear hormone receptor, which modulates the transcriptional regulation of lipid and glucose homeostasis. It plays a crucial role in many of the metabolic and inflammatory systems. It is a key target for many of the anti-diabetic medications. Perturbation of PPARγ activity is also observed in many of the cancers involving colon, breast, gastric and lung. Thus, it is considered to be the hub molecule for targeting many of these cellular disorders. Seaweed metabolites have been well documented to be novel structural entities with a broad spectrum of pharmacological values. However, it is yet to be utilized for screening PPARγ agonists.Methods: In this study, virtual screening of PPARγ Ligand Binding Domain (LBD) was performed against the datasets from SeaWeed Metabolite Database (SWMD) using Schrodinger Glide High Throughput Virtual Screening module to identify potential PPARγ agonists. Further, the most potential lead was also subjected to molecular dynamics simulation to infer the stability of complex formation.Results: The results have revealed that bromophenolic compounds from the genus Avrainvillea to interact with documented key residues of LBD involved in agonist interactions. Many other metabolites from the genus Rhodomela, Leathesia, Bifurcaria, Osmundaria, Cymopolia also showed significant interactions with LBD of PPARγ.Conclusion: The insights from this study will pave the way for further exploration of lead compounds from seaweed metabolites targeting PPARγ. Â

IN SILICO SCREENING OF POTENT PPARGAMMA AGONISTS AMONG NATURAL ANTICANCER COMPOUNDS OF INDIAN ORIGIN

ABSTRACTObjective: Naturally occurring anticancer compounds of Indian origin are well-known for potential therapeutic values. A better understanding ofthe intermolecular interactions of these compounds with peroxisome proliferator-activated receptor gamma (PPARγ) is essential, as its activity isreported in many of the cancers involving colon, breast, gastric, and lung. By this study, it is attempted to perform an in silico screening of naturalanticancer compounds of Indian origin with PPARγ ligand binding domain (LBD). The potential anticancer leads ranked in this study will also exertan additional advantage of PPARγ activity modulation. As PPARγ is also an important nuclear hormone receptor that modulates transcriptionalregulation of lipid and glucose homeostasis and also a key target for many of the anti-diabetic medications, the compounds ranked by this study willalso be utilized for other related therapeutic effects.Methods: This study features in silico screening of compounds from Indian Plant Anticancer compounds database against PPARγ LBD main performedSchrodinger glide virtual screening and docking module to delineate potential PPARγ agonists. Finally, the most potential lead was also subjected tomolecular dynamics simulation to infer the stability of complex formation.Results: The results reveal that majority of the top ranking compounds that interact with LBD was found to be flavonoids, and all these compoundswere found to interact with key residues involved in PPARγ agonist interactions.Conclusion: The leads from this study would be helpful in better understanding of the potential of naturally occurring anticancer compounds ofIndian origin toward targeting PPARγ.Keywords: Peroxisome proliferator-activated receptor-gamma, Agonists, Docking, Natural compounds, Anticancer.Â

The human body at cellular resolution: the NIH Human Biomolecular Atlas Program

Abstract: Transformative technologies are enabling the construction of three-dimensional maps of tissues with unprecedented spatial and molecular resolution. Over the next seven years, the NIH Common Fund Human Biomolecular Atlas Program (HuBMAP) intends to develop a widely accessible framework for comprehensively mapping the human body at single-cell resolution by supporting technology development, data acquisition, and detailed spatial mapping. HuBMAP will integrate its efforts with other funding agencies, programs, consortia, and the biomedical research community at large towards the shared vision of a comprehensive, accessible three-dimensional molecular and cellular atlas of the human body, in health and under various disease conditions

A Possible Alignment Between the Orbits of Planetary Systems and their Visual Binary Companions

Astronomers do not have a complete picture of the effects of wide-binary companions (semimajor axes greater than 100 au) on the formation and evolution of exoplanets. We investigate these effects using new data from Gaia Early Data Release 3 and the Transiting Exoplanet Survey Satellite mission to characterize wide-binary systems with transiting exoplanets. We identify a sample of 67 systems of transiting exoplanet candidates (with well-determined, edge-on orbital inclinations) that reside in wide visual binary systems. We derive limits on orbital parameters for the wide-binary systems and measure the minimum difference in orbital inclination between the binary and planet orbits. We determine that there is statistically significant difference in the inclination distribution of wide-binary systems with transiting planets compared to a control sample, with the probability that the two distributions are the same being 0.0037. This implies that there is an overabundance of planets in binary systems whose orbits are aligned with those of the binary. The overabundance of aligned systems appears to primarily have semimajor axes less than 700 au. We investigate some effects that could cause the alignment and conclude that a torque caused by a misaligned binary companion on the protoplanetary disk is the most promising explanation

Osteogenic potential of laser modified and conditioned titanium zirconium surfaces

Statement of Problem: The osseointegration of dental implant is related to their composition and surface treatment. Titanium zirconium (TiZr) has been introduced as an alternative to the commercially pure titanium and its alloys as dental implant material, which is attributed to its superior mechanical and biological properties. Surface treatments of TiZr have been introduced to enhance their osseointegration ability; however, reliable, easy to use surface modification technique has not been established. Purpose: The purpose of this study was to evaluate and compare the effect of neodymium-doped yttrium aluminum garnet (Nd-YAG) laser surface treatment of TiZr implant alloy on their osteogenic potential. Materials and Methods: Twenty disc-shaped samples of 5 mm diameter and 2 mm height were milled from the TiZr alloy ingot. The polished discs were ultrasonically cleaned in distilled water. Ten samples each were randomly selected as Group A control samples and Group B consisted of Nd-YAG laser surface etched and conditioned test samples. These were evaluated for cellular response. Cellular adhesion and proliferation were quantified, and the results were statistically analyzed using nonparametric analysis. Cellular morphology was observed using electron and epiflurosence microscopy. Results: Nd-YAG laser surface modified and conditioned TiZr samples increased the osteogenic potential. Conclusion: Nd-YAG laser surface modification of TiZr, improves the cellular activity, surface roughness, and wettability, thereby increasing the osteogenic potential

Inhibition of IKKβ by celastrol and its analogues – an in silico and in vitro approach

Context: Alzheimer’s disease (AD) is the most common form of dementia affecting the aged population and neuroinflammation is one of the most observed AD pathologies. NF-κB is the central regulator of inflammation and inhibitor κB kinase (IKK) is the converging point in NF-κB activation. Celastrol is a natural triterpene used as a treatment for inflammatory conditions. Objective: This study determines the neuroprotective and inhibitory effect of celastrol on amyloid beta1-42 (Aβ1-42) induced cytotoxicity and IKKβ activity, respectively. Materials and methods: Retinoic acid differentiated IMR-32 cells were treated with celastrol (1 μM) before treatment with Aβ1-42 (IC30 10 μM) for 24 h. The cytotoxicity and IKK phosphorylation were measured by MTT and western blotting analysis, respectively. We screened 36 celastrol analogues for the IKKβ inhibition by molecular docking and evaluated their drug like properties to delineate the neuroprotective effects. Results: Celastrol (1 μM) inhibited Aβ1-42 (10 μM) induced IκBα phosphorylation and protected IMR-32 cells from cell death. Celastrol and 25 analogues showed strong binding affinity with IKKβ as evidenced by strong hydrogen-bonding interactions with critical active site residues. All the 25 analogues displayed strong anti-inflammatory properties but only 11 analogues showed drug-likeness. Collectively, molecule 15 has highest binding affinity, CNS activity and more drug likeness than parent compound celastrol. Discussion and conclusion: The decreased expression of pIκBα in celastrol pretreated cells affirms the functional representation of inhibited IKKβ activity in these cells. The neuroprotective potentials of celastrol and its analogues may be related to IKK inhibition

Differential Mechanisms of Cell Death Induced by HDAC Inhibitor SAHA and MDM2 Inhibitor RG7388 in MCF-7 Cells

Gene expression is often altered by epigenetic modifications that can significantly influence the growth ability and progression of cancers. SAHA (Suberoylanilide hydroxamic acid, also known as Vorinostat), a well-known Histone deacetylase (HDAC) inhibitor, can stop cancer growth and metastatic processes through epigenetic alterations. On the other hand, Letrozole is an aromatase inhibitor that can elicit strong anti-cancer effects on breast cancer through direct and indirect mechanisms. A newly developed inhibitor, RG7388 specific for an oncogene-derived protein called MDM2, is in clinical trials for the treatment of various cancers. In this paper, we performed assays to measure the effects of cell cycle arrest resulting from individual drug treatments or combination treatments with SAHA + letrozole and SAHA + RG7388, using the MCF-7 breast cancer cells. When SAHA was used individually, or in combination treatments with RG7388, a significant increase in the cytotoxic effect was obtained. Induction of cell cycle arrest by SAHA in cancer cells was evidenced by elevated p21 protein levels. In addition, SAHA treatment in MCF-7 cells showed significant up-regulation in phospho-RIP3 and MLKL levels. Our results confirmed that cell death caused by SAHA treatment was primarily through the induction of necroptosis. On the other hand, the RG7388 treatment was able to induce apoptosis by elevating BAX levels. It appears that, during combination treatments, with SAHA and RG7388, two parallel pathways might be induced simultaneously, that could lead to increased cancer cell death. SAHA appears to induce cell necroptosis in a p21-dependent manner, and RG7388 seems to induce apoptosis in a p21-independent manner, outlining differential mechanisms of cell death induction. However, further studies are needed to fully understand the intracellular mechanisms that are triggered by these two anti-cancer agents

Cell Cycle Arrest and Cytotoxic Effects of SAHA and RG7388 Mediated through p21^WAF1/CIP1 and p27^KIP1 in Cancer Cells

Background and Objective: Alterations in gene expressions are often due to epigenetic modifications that can have a significant influence on cancer development, growth, and progression. Lately, histone deacetylase inhibitors (HDACi) such as suberoylanilide hydroxamic acid (SAHA, or vorinostat, MK0683) have been emerging as a new class of drugs with promising therapeutic benefits in controlling cancer growth and metastasis. The small molecule RG7388 (idasanutlin, R05503781) is a newly developed inhibitor that is specific for an oncogene-derived protein called MDM2, which is also in clinical trials for the treatment of various types of cancers. These two drugs have shown the ability to induce p21 expression through distinct mechanisms in MCF-7 and LNCaP cells, which are reported to have wild-type TP53. Our understanding of the molecular mechanism whereby SAHA and RG7388 can induce cell cycle arrest and trigger cell death is still evolving. In this study, we performed experiments to measure the cell cycle arrest effects of SAHA and RG7388 using MCF-7 and LNCaP cells. Materials and Methods: The cytotoxicity, cell cycle arrest, and apoptosis/necroptosis effects of the SAHA and RG7388 treatments were assessed using the Trypan Blue dye exclusion (TBDE) method, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, fluorescence assay with DEVD-amc substrate, and immunoblotting methods. Results: The RG7388 treatment was able to induce cell death by elevating p21WAF1/CIP1 through inhibition of MDM2 in LNCaP, but not in MCF-7 cells, even though there was evidence of p53 elevation. Hence, we suspect that there is some level of uncoupling of p53-mediated transcriptional induction of p21WAF1/CIP1 in MCF-7 cells. Conclusion: Our results from MCF-7 and LNCaP cells confirmed that SAHA and RG7388 treatments were able to induce cell death via a combination of cell cycle arrest and cytotoxic mechanisms. We speculate that our findings could lead to the development of newer treatments for breast and prostate cancers with drug combinations including HDACi

Inhibition of IKKβ by celastrol and its analogues – an <i>in silico</i> and <i>in vitro</i> approach

<p><b>Context:</b> Alzheimer’s disease (AD) is the most common form of dementia affecting the aged population and neuroinflammation is one of the most observed AD pathologies. NF-κB is the central regulator of inflammation and inhibitor κB kinase (IKK) is the converging point in NF-κB activation. Celastrol is a natural triterpene used as a treatment for inflammatory conditions.</p> <p><b>Objective:</b> This study determines the neuroprotective and inhibitory effect of celastrol on amyloid beta_1-42 (Aβ_1-42) induced cytotoxicity and IKKβ activity, respectively.</p> <p><b>Materials and methods:</b> Retinoic acid differentiated IMR-32 cells were treated with celastrol (1 μM) before treatment with Aβ_1-42 (IC₃₀ 10 μM) for 24 h. The cytotoxicity and IKK phosphorylation were measured by MTT and western blotting analysis, respectively. We screened 36 celastrol analogues for the IKKβ inhibition by molecular docking and evaluated their drug like properties to delineate the neuroprotective effects.</p> <p><b>Results:</b> Celastrol (1 μM) inhibited Aβ_1-42 (10 μM) induced IκBα phosphorylation and protected IMR-32 cells from cell death. Celastrol and 25 analogues showed strong binding affinity with IKKβ as evidenced by strong hydrogen-bonding interactions with critical active site residues. All the 25 analogues displayed strong anti-inflammatory properties but only 11 analogues showed drug-likeness. Collectively, molecule 15 has highest binding affinity, CNS activity and more drug likeness than parent compound celastrol.</p> <p><b>Discussion and conclusion:</b> The decreased expression of pIκBα in celastrol pretreated cells affirms the functional representation of inhibited IKKβ activity in these cells. The neuroprotective potentials of celastrol and its analogues may be related to IKK inhibition.</p