Molecular insights into the potential effects of selective estrogen receptor ß agonists in Alzheimer's and Parkinson's diseases.

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative disorders. Pathologically, AD and PD are characterized by the accumulation of misfolded proteins. Hence, they are also called as proteinopathy diseases. Gender is considered as one of the risk factors in both diseases. Estrogens are widely accepted to be neuroprotective in several neurodegenerative disorders. Estrogens can be produced in the central nervous system, where they are called as neurosteroids. Estrogens mediate their neuroprotective action mainly through their actions on estrogen receptor alpha (ERα) and estrogen receptor beta (ERß). However, ERα is mainly involved in the growth and development of the primary and secondary sexual organs in females. Hence, the activation of ERα is associated with undesired side effects such as gynecomastia and increase in the risk of breast cancer, thromboembolism, and feminization. Therefore, selective activation of ERß is often considered to be safer. In this review, we explore the role of ERß in regulating the expression and functions of AD- and PD-associated genes. Additionally, we discuss the association of these genes with the amyloid-beta peptide (Aß) and α-synuclein mediated toxicity. Ultimately, we established a correlation between the importance of ERß activation and the process underlying ERß's neuroprotective mechanisms in AD and PD.

Network-based drug repositioning of linagliptin as a potential agent for uterine fibroids targeting transforming growth factor-beta mediated fibrosis.

Uterine fibroid is the most common non-cancerous tumor with no satisfactory options for long-term pharmacological treatment. Fibroblast activation protein-α (FAP) is one of the critical enzymes that enhances the fibrosis in uterine fibroids. Through STITCH database mining, we found that dipeptidyl peptidase-4 inhibitors (DPP4i) have the potential to inhibit the activity of FAP. Both DPP4 and FAP belong to the dipeptidyl peptidase family and share a similar catalytic domain. Hence, ligands which have a binding affinity with DPP4 could also bind with FAP. Among the DPP4i, linagliptin exhibited the highest binding affinity (Dock score = -8.562 kcal/mol) with FAP. Our study uncovered that the differences in the S2 extensive-subsite residues between DPP4 and FAP could serve as a basis for designing selective inhibitors specifically targeting FAP. Furthermore, in a dynamic environment, linagliptin was able to destabilize the dimerization interface of FAP, resulting in potential inhibition of its biological activity. True to the in-silico results, linagliptin reduced the fibrotic process in estrogen and progesterone-induced fibrosis in rat uterus. Furthermore, linagliptin reduced the gene expression of transforming growth factor-ß (TGF-ß), a critical factor in collagen secretion and fibrotic process. Masson trichrome staining confirmed that the anti-fibrotic effects of linagliptin were due to its ability to reduce collagen deposition in rat uterus. Altogether, our research proposes that linagliptin has the potential to be repurposed for the treatment of uterine fibroids.

Rational Design of Dual Inhibitors for Alzheimer's Disease: Insights from Computational Screening of BACE1 and GSK-3ß.

BACKGROUND: Alzheimer's disease (AD) is one of the most concerned neurodegenerative disorders across the world characterized by amyloid-beta (Aß) plaques and neurofibrillary tangles (NFTs), leading to cognitive decline and memory loss. Targeting key pathways involved in AD like Aß and NFT pathways, are crucial for the development of effective therapeutic strategies. In this study, we aimed to identify and establish promising dual inhibitors targeting BACE1 and GSK-3ß, two proteins implicated in Aß and NFT formation respectively. METHODS: We have used molecular docking, ADME property analysis, and MMGBSA calculations for the identification of hit molecules and further evaluation of binding affinity, drug-like properties, and stability against BACE1 and GSK-3ß. RESULTS: Our results demonstrated strong binding affinities of ZINC000034853956 towards the active sites of both proteins, with favorable interactions involving key residues crucial for inhibitory activity. Additionally, ZINC000034853956 exhibited favorable drug-like properties. MD simulations revealed the stable binding of ZINC000034853956 to both BACE1 and GSK-3ß over a 50 ns period, with consistent ligand-protein interactions, such as hydrogen bonding and hydrophobic contacts. These findings highlight the potential of ZINC000034853956 as a promising candidate for AD treatment, acting as a dual inhibitor targeting both BACE1 and GSK-3ß. Overall, our study provides valuable insights into the potential of ZINC000034853956 as a dual inhibitor for AD. The strong binding affinity, favorable drug-like properties, and stability observed in MD simulations support its suitability for further optimization and preclinical studies. CONCLUSION: Further investigations are warranted to elucidate the precise molecular mechanisms and therapeutic benefits of ZINC000034853956. Our findings offer hope for the development of novel therapeutic interventions targeting crucial pathways involved in AD neurodegeneration.

The identification of cianidanol as a selective estrogen receptor beta agonist and evaluation of its neuroprotective effects on Parkinson's disease models.

AIM: The present study aims to identify selective estrogen receptor beta (ERß) agonists and to evaluate the neuroprotective mechanism in Parkinson's disease (PD) models. MAIN METHODS: In-silico studies were carried out using Maestro and GROMACS. Neuroprotective activity and apoptosis were evaluated using cytotoxicity assay and flow cytometry respectively. Gene expression studies were carried out by reverse transcription polymerase chain reaction. Motor and cognitive functions were assessed by actophotometer, rotarod, catalepsy, and elevated plus maze. The neuronal population in the substantia nigra and striatum of rats was assessed by hematoxylin and eosin staining. KEY FINDINGS: Cianidanol was identified as a selective ERß agonist through virtual screening. The cianidanol-ERß complex is stable during the 200 ns simulation and was able to retain the interactions with key amino acid residues. Cianidanol (25 µM) prevents neuronal toxicity and apoptosis induced by rotenone in differentiated SH-SY5Y cells. Additionally, cianidanol (25 µM) increases the expression of ERß, cathepsin D, and Nrf2 transcripts. The neuroprotective effects of cianidanol (25 µM) were reversed in the presence of a selective ERß antagonist. In this study, we found that selective activation of ERß could decrease the transcription of α-synuclein gene. Additionally, cianidanol (10, 20, 30 mg/kg, oral) improves the motor and cognitive deficit in rats induced by rotenone. SIGNIFICANCE: Cianidanol shows neuroprotective action in PD models and has the potential to serve as a novel therapeutic agent for the treatment of PD.

Side effects based network construction and drug repositioning of ropinirole as a potential molecule for Alzheimer's disease: an in-silico, in-vitro, and in-vivo study.

Alzheimer's disease (AD) is the leading cause of dementia in older adults. Drug repositioning is a process of finding new therapeutic applications for existing drugs. One of the methods in drug repositioning is to use the side-effect profile of a drug to identify a new therapeutic indication. The drugs with similar side-effects may act on similar biological targets and could affect the same biochemical process. In this study, we explored the Food and Drug Administration-approved drugs using PROMISCUOUS database to find those that have adverse effects profile comparable with the ligands being studied or used to treat AD. Here, we found that the ropinirole, a dopamine receptor agonist, shared a maximum number of side-effects with the drugs proven beneficial for treating AD. Furthermore, molecular modelling demonstrated that ropinirole exhibited strong binding affinity (-9.313 kcal/mol) and best ligand efficiency (0.49) with sigma-1 receptor. Here, we observed that the quaternary amino group of ropinirole is essential for binding with sigma-1 receptor. Molecular dynamic simulation indicated that the movement of the carboxy-terminal helices (α4/α5) could play a major role in the receptor's physiological functions. The neurotoxicity induced by Aß25-35 in SH-SY5Y cells was reduced by ropinirole at concentrations 10, 30, and 50 µM. The effect on spatial learning and memory was examined in mice with Aß25-35 induced memory deficit using the radial arm maze. Ropinirole (10 and 20 mg/kg) significantly improved the short and long-term memories in the radial arm maze test. Our results suggest that ropinirole has the potential to be repositioned for AD treatment.Communicated by Ramaswamy H. Sarma.

A preliminary study to identify existing drugs for potential repurposing in breast cancer based on side effect profile.

Breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer-related death in women after lung cancer. The present study aims to identify potential drug candidates using the PROMISCUOUS database for breast cancer based on side effect profile and then proceed with in silico and in vitro studies. PROMISCUOUS database was used to construct a group of drugs that share maximum side effects with letrozole. Based on the existing literature, ropinirole, risperidone, pregabalin, and gabapentin were selected for in silico and in vitro studies. The molecular docking was carried out using AUTODOCK 4.2.6. MCF-7 cell line was used to evaluate the anti-cancer activity of the selected drugs. PROMISCUOUS database revealed that as many as 23 existing drugs shared between 62 and 79 side-effects with letrozole. From docking result, we found that, ropinirole showed a good binding affinity (-7.7 kcal/mol) against aromatase compared to letrozole (-7.1 kcal/mol) which was followed by gabapentin (-6.4 kcal/mol), pregabalin (-5.7 kcal/mol) and risperidone (-5.1 kcal/mol). From the in vitro results, ropinirole and risperidone showed good anti-cancer activity of IC50 with 40.85±11.02 µg/ml and 43.10±9.58 µg/ml cell viability. Based on this study results and existing literature we conclude that risperidone, pregabalin, and gabapentin are not ideal candidates for repurposing in breast cancer but ropinirole could be an excellent choice for repurposing in breast cancer after further studies.

A Perspective on Therapeutic Applications and Strategies to Mitigate Toxicity of Metallic Nanoparticles.

Metallic nanoparticles (MNPs) have been widely used for diagnostic and therapeutic purposes in clinical practice. A number of MNP formulations are being investigated in clinical trials for various applications. This increase in the use of NPs results in higher exposure to humans, leading to toxicity issues. Hence, it is necessary to determine the possible undesirable effects of the MNPs after in-vivo application and exposure. One of the main reasons for the toxicity of MNPs is the release of their respective metallic ions throughout the body. Many research studies are in progress investigating the various strategies to reduce the toxicity of MNPs. These research studies aim to change the size, dose, agglomeration, release, and excretion rates of MNPs. In this perspective review, we discussed the possible strategies to improve the therapeutic effects of MNPs through various processes, with lessons learned from the studies involving silver nanoparticles (AgNPs). We also discussed the ways to manage the toxicity of MNPs by purification, surface functionalization, synergistic effect, and targeted therapy approach. All these strategies could reduce the dose of the MNPs without compromising their therapeutic benefits, which could decrease the toxicity of MNPs. Additionally, we briefly discussed the market and toxicology testing for FDA-regulated MNPs.

Importance of Fibrosis in the Pathogenesis of Uterine Leiomyoma and the Promising Anti-fibrotic Effects of Dipeptidyl Peptidase-4 and Fibroblast Activation Protein Inhibitors in the Treatment of Uterine Leiomyoma.

Uterine fibroid or leiomyoma is the most common benign uterus tumor. The tumor is primarily composed of smooth muscle (fibroid) cells, myofibroblast, and a significant amount of extracellular matrix components. It mainly affects women of reproductive age. They are uncommon before menarche and usually disappear after menopause. The fibroids have excessive extracellular matrix components secreted by activated fibroblast cells (myofibroblast). Myofibroblast has the characteristics of fibroblast and smooth muscle cells. These cells possess contractile capability due to the expression of contractile proteins which are normally found only in muscle tissues. The rigid nature of the tumor is responsible for many side effects associated with uterine fibroids. The current drug treatment strategies are primarily hormone-driven and not anti-fibrotic. This paper emphasizes the fibrotic background of uterine fibroids and the mechanisms behind the deposition of excessive extracellular matrix components. The transforming growth factor-ß, hippo, and focal adhesion kinase-mediated signaling pathways activate the fibroblast cells and deposit excessive extracellular matrix materials. We also exemplify how dipeptidyl peptidase-4 and fibroblast activation protein inhibitors could be beneficial in reducing the fibrotic process in leiomyoma. Dipeptidyl peptidase-4 and fibroblast activation protein inhibitors prevent the fibrotic process in organs such as the kidneys, lungs, liver, and heart. These inhibitors are proven to inhibit the signaling pathways mentioned above at various stages of their activation. Based on literature evidence, we constructed a narrative review on the mechanisms that support the beneficial effects of dipeptidyl peptidase-4 and fibroblast activation protein inhibitors for treating uterine fibroids.

The principal molecular mechanisms behind the activation of Keap1/Nrf2/ARE pathway leading to neuroprotective action in Parkinson's disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder. PD is associated with the loss of dopaminergic neurons in the substantia nigra pars compacta region of the midbrain. Present therapies for PD provide only symptomatic relief by restoring the dopamine (DA) level. However, they are not disease modifying agents and so they do not delay the disease progression. Alpha-synuclein aggregation, oxidative stress, mitochondrial dysfunction and chronic inflammation are considered to be the major pathological mechanisms mediating neurodegeneration in PD. To resist oxidative stress, the human body has an antioxidant defence mechanism consisting of many antioxidants and cytoprotective genes. The expression of those genes are largely controlled by the Kelch-like ECH-associated protein 1/Nuclear factor - erythroid - 2 - related factor 2/Antioxidant response element (Keap1/Nrf2/ARE) signalling pathway. The transcription factor Nrf2 is activated in response to oxidative or electrophilic stress and protects the cells from oxidative stress and inflammation. Nrf2 has been widely considered as a therapeutic target for neurodegeneration and several drugs are now being tested in clinical trials. Regulation of the Keap1/Nrf2/ARE pathway by small molecules which can act as Nrf2 activators could be effective for treating oxidative stress and neuroinflammation in PD. In this review, we had discussed the principal molecular mechanisms behind the neuroprotective effects of Keap1/Nrf2/ARE pathway in PD. Additionally, we also discussed the small molecules and phytochemicals that could activate the Nrf2 mediated anti-oxidant pathway for neuroprotection in PD.

Building and behavior of a pH-stimuli responsive chitosan nanoparticles loaded with folic acid conjugated gemcitabine silver colloids in MDA-MB-453 metastatic breast cancer cell line and pharmacokinetics in rats.

The pH-stimuli release behavior of nanoformulations may enhance the success rate of chemotherapeutic drugs in cancers by site-specific delivery of drugs to cancer tissues. The aim of the present study was to prepare chitosan (CS) nanoparticles (NPs) with previously synthesized folic acid (FA) capped silver nanoparticles (AgNPs) loaded with the anti-cancer drug gemcitabine (GEM) (FA-GEM-AgNPs). The CS-FA-GEM-AgNPs (CS-NPs) were characterized with dynamic light scattering (DLS), transmission electron microscopy (TEM), energy dispersive x-ray analysis (EDAX), selected area electron diffraction (SAED), and differential scanning calorimetric (DSC) analyses. The in-vitro drug release of GEM was evaluated in media of different pH. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was carried out to determine the cytotoxic effects of the prepared nanoformulations in media with various pH. The time- and pH-dependent apoptotic cell death induced by CS-NPs with MDA-MB-453 human breast cancer cell line was observed using acridine orange (AO)/ethidium bromide (EtBr) staining. The pharmacokinetic parameters were studied with high-performance liquid chromatography (HPLC) and atomic absorption spectroscopy (AAS). Two batches of CS-NPs formulations were prepared, one with AgNPs of particle size 143 nm and the other with 244 nm. The particle size for CS-NPs-I (FA-GEM-AgNPs-143 nm) and CS-NPs-II (FA-GEM-AgNPs-244 nm) was found to be 425 and 545 nm, respectively. The zeta potential was found to be 36.1 and 37.5 mV for CS-NPs-I and CS-NPs-II, respectively. CS-NPs-I and CS-NPs-II showed a polydispersity index (PDI) of 0.240 and 0.261, respectively. A TEM study confirmed the spherical nature of the NPs. The nanoformulations exerted pH-dependant effect against MDA-MB-453 cells with relatively higher cytotoxicity at the lower pH than at higher pH levels. The pharmacokinetic profile and tissue distribution of CS-NPs in rats exerted drug release in a pH-dependent manner with enhanced excretion of Ag+. An optimized nanoformulation for pH-stimuli responsive release of GEM was successfully developed for future therapeutic exploration.

Syringaresinol as a novel androgen receptor antagonist against wild and mutant androgen receptors for the treatment of castration-resistant prostate cancer: molecular docking, in-vitro and molecular dynamics study.

Phytoestrogens are dietary estrogens having similar structure as of estrogen. Some of these phytoestrogens are androgen receptor (AR) antagonists and exhibit preventive role in the prostate cancer. However, in androgen-independent prostate cancer (AIPC) the ARs were mutated (T877A, W741L, F876L, etc.) and these mutant ARs convert the antagonist to agonist. Our aim in this study is to find phytoestrogens that could function as an antagonist with wild and mutant ARs. The phytoestrogens were analyzed for binding affinity with wild and mutant ARs in agonist and antagonist conformations. The point mutations were carried out using Chimera. The antagonist AR conformation was modeled using Modeller. We hypothesize that the compounds having binding affinity with agonist AR conformation could not function as a full or pure antagonist. Most of the phytoestrogens have binding affinity with agonist AR conformation contradicting previous results. For example, genistein which is a widely studied isoflavone has known AR antagonist property. However, in our study, it had good binding affinity with agonist AR conformation. Hence, to confirm our hypothesis, we tested genistein in LNCaP (T877A mutant AR) cells by qPCR studies. The genistein functioned as an antagonist only in the presence of an androgen indicting a partial agonist type of activity. The in-vitro results supported our docking hypothesis. We applied this principle and found syringaresinol could function as an antagonist with wild and mutated ARs. Further, we carried out molecular dynamics for the hit molecule to confirm its antagonist binding mode with mutant AR.Communicated by Ramaswamy H. Sarma.

G-Lymphatic, Vascular and Immune Pathways for Aß Clearance Cascade and Therapeutic Targets For Alzheimer's Disease.

Alzheimer's disease is an age-related neurodegenerative disease. The factors causing Alzheimer's disease are numerous. Research on humans and rodent models predicted various causative factors involved in Alzheimer's disease progression. Among them, neuroinflammation, oxidative stress, and apoptosis play a major role because of the accumulation of extracellular amyloid-beta peptides. Here, the clearance of amyloid beta-peptide plays a major role because of the imbalance in the production and clearance of the amyloid beta-peptide. Additionally, neuroinflammation by microglia, astrocytes, cytokines, chemokines, and the complement system also has a major role in Alzheimer's disease. The physiological clearance pathways involved in amyloid beta-peptide are glymphatic, vascular, and immune pathways. Amyloid precursor protein, low-density lipoprotein receptor-related protein 1, receptor for the advanced glycation end product, apolipoprotein E, clusterin, aquaporin 4, auto-antibodies, complement system, cytokines, and microglia are involved in amyloid beta-peptide clearance pathways across the blood-brain barrier. The plaque formation in the brain by alternative splicing of amyloid precursor protein and production of misfolded protein results in amyloid-beta agglomeration. This insoluble amyloid-beta leads to a neurodegenerative cascade and neuronal cell death occurs. Studies had shown that disturbed sleep may be a risk factor for dementia and cognitive decline. In this review, the therapeutic targets for Alzheimer'sdisease via focusing on pathways for amyloid-beta clearance are discussed.

Identification of (2R,3R)-2-(3,4-dihydroxyphenyl)chroman-3-yl-3,4,5-trihydroxy benzoate as multiple inhibitors of SARS-CoV-2 targets; a systematic molecular modelling approach.

Coronavirus disease of 2019 (COVID-19) is a zoonotic disease caused by a new severe acute respiratory syndrome (SARS-CoV-2) which has quickly resulted in a pandemic. Recent anti-COVID-19 drug discoveries are leaning towards repurposing phytochemicals which have been previously reported for SARS and MERS-CoV outbreaks. However, they have been either virtually screened or tested so far against mono targets and the potent derivatives of virtually sorted lead molecules remain elusive. We aimed to identify the phytochemicals having potentials to inhibit SARS CoV-2 infection via multiple targets. The selected 132 phytochemicals were virtually screened using a structure based in silico technique against main protease (Mpro) which is a potential target of SARS CoV-2. Six compounds were selected based on the LibDock scores and further subjected to induced fit docking using the CDOCKER module of DS. Two compounds namely cinnamtannin-B and gallocatechin gallate were identified as top HITS against main protease (Mpro). Based on the Lipinski rule of five (L-ROF) and synthetic feasibility, gallocatechin gallate was taken for our further studies. Six analogues of gallocatechin gallate were screened against the next important targets such as RNA-dependent RNA polymerase (RdRp), angiotensin converting enzyme-2 (ACE2), transmembrane protease serine -2 (TMPRSS2) and interleukin-6 (IL-6) along with main protease (Mpro). Our molecular docking results reveal that a gallocatechin analogue (GC-2) namely (2R,3R)-2-(3,4-dihydroxyphenyl)chroman-3-yl-3,4,5-trihydroxy benzoate has shown potential to inhibit multiple targets of SARS CoV-2. Further, the molecular dynamics study was carried out to ascertain the stability of the GC-2 and RdRp complex.

Design, Synthesis and Evaluation of Novel Substituted (5-methyl-1H-pyrazol-3-yl)- 1,3,4-oxadiazole as Potent Androgen Receptor Antagonist.

BACKGROUND: Androgen Receptor (AR) is one of the highly explored targets for the treatment of prostate cancer. The emergence of point mutation in the Ligand Binding Domain (LBD) of AR has resulted in the development of resistance against AR antagonist. The point mutation T877A, W741L and F876L confer resistance to flutamide, bicalutamide and enzalutamide respectively. There is no AR antagonist in the present clinical set up without resistance. Hence, our aim in this study is to design a novel molecule to overcome the resistance caused by point mutation. METHODS: Here, we developed novel AR antagonist bearing (5-methyl-1H-pyrazol-3-yl)-1, 3,4-oxadiazole core by rational drug design. The test molecules 8a-h were synthesized from the corresponding dihydrazide compounds 7a-h on treatment with phosphorous oxychloride on reflux conditions. The structure of the molecules was confirmed from spectral data such as IR, 1H-NMR, HRMS and 13C-NMR. The synthesized compounds were screened for cytotoxicity in prostate cancer cell lines LNCaP-FGC and PC3. The confirmation of AR mediated activity of the test compounds was confirmed by gene expression study. The interaction of the best active ligands with mutant AR was predicted and drug design was rationalized through docking studies. RESULTS: The test compounds 8a-h were synthesized and the structures were conformed using suitable techniques like IR, 1H-NMR, HRMS and 13C-NMR. Among the tested compounds, 8b and 8d showed potent antiproliferative activity against mutant AR cell lines. Further, these compounds significantly decreased the gene expression of prostate cancer biomarkers. CONCLUSION: In this study, we have identified a potential hit molecule for AR antagonism that could be further developed to obtain a potent clinical candidate.

Quillaja saponin: A prospective emulsifier for the preparation of solid lipid nanoparticles.

Quillaja saponin (QS) is a non-ionic amphiphilic surfactant of natural origin. In the present study, we evaluated its potential to form solid lipid nanoparticles (SLNs) in the presence of stearic acid (SA) as a lipid carrier and imatinib mesylate (IM) as a model drug. IM loaded solid lipid nanoparticles (IMSLNs) were prepared using the hot homogenisation method. Characterisation of IMSLNs revealed that they were quasi-spherical in shape, neutrally charged and 143.5-641.9nm in size. Haemolysis, a toxicity issue of QS was not observed in SLNs. Comparative in vitro cytotoxicity analyses performed in human breast cancer cell line MCF7 revealed that IMSLNs were more toxic than IM. On the other hand, in vitro viability studies in the RAW264.7 cell line did not show any sign of toxicity by IMSLNs. Our results indicate that QS hold great potential in nano drug delivery as an emulsifier.