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1.
Proc Natl Acad Sci U S A ; 119(22): e2202723119, 2022 05 31.
Article in English | MEDLINE | ID: mdl-35622886

ABSTRACT

Arp2/3 complex nucleates branched actin filaments that provide pushing forces to drive cellular processes such as lamellipodial protrusion and endocytosis. Arp2/3 complex is intrinsically inactive, and multiple classes of nucleation promoting factors (NPFs) stimulate its nucleation activity. When activated by WASP family NPFs, the complex must bind to the side of a preexisting (mother) filament of actin to complete the nucleation process, ensuring that WASP-mediated activation creates branched rather than linear actin filaments. How actin filaments contribute to activation is currently not understood, largely due to the lack of high-resolution structures of activated Arp2/3 complex bound to the side of a filament. Here, we present the 3.9-Å cryo-electron microscopy structure of the Arp2/3 complex at a branch junction. The structure reveals contacts between Arp2/3 complex and the side of the mother actin filament that likely stimulate subunit flattening, a conformational change that allows the actin-related protein subunits in the complex (Arp2 and Arp3) to mimic filamentous actin subunits. In contrast, limited contact between the bottom half of the complex and the mother filament suggests that clamp twisting, a second major conformational change observed in the active state, is not stimulated by actin filaments, potentially explaining why actin filaments are required but insufficient to trigger nucleation during WASP-mediated activation. Along with biochemical and live-cell imaging data and molecular dynamics simulations, the structure reveals features critical for the interaction of Arp2/3 complex with actin filaments and regulated assembly of branched actin filament networks in cells.


Subject(s)
Actin Cytoskeleton , Actin-Related Protein 2-3 Complex , Actin Cytoskeleton/chemistry , Actin-Related Protein 2-3 Complex/chemistry , Actin-Related Protein 2-3 Complex/metabolism , Cryoelectron Microscopy , Cytoskeleton/metabolism , Molecular Dynamics Simulation , Protein Conformation , Wiskott-Aldrich Syndrome Protein/metabolism
2.
J Biol Chem ; 299(9): 105169, 2023 09.
Article in English | MEDLINE | ID: mdl-37595874

ABSTRACT

Actin-related protein 2/3 complex (Arp2/3 complex) catalyzes the nucleation of branched actin filaments that push against membranes in processes like cellular motility and endocytosis. During activation by WASP proteins, the complex must bind WASP and engage the side of a pre-existing (mother) filament before a branched filament is nucleated. Recent high-resolution structures of activated Arp2/3 complex revealed two major sets of activating conformational changes. How these activating conformational changes are triggered by interactions of Arp2/3 complex with actin filaments and WASP remains unclear. Here we use a recent high-resolution structure of Arp2/3 complex at a branch junction to design all-atom molecular dynamics simulations that elucidate the pathway between the active and inactive states. We ran a total of ∼4.6 microseconds of both unbiased and steered all-atom molecular dynamics simulations starting from three different binding states, including Arp2/3 complex within a branch junction, bound only to a mother filament, and alone in solution. These simulations indicate that the contacts with the mother filament are mostly insensitive to the massive rigid body motion that moves Arp2 and Arp3 into a short pitch helical (filament-like) arrangement, suggesting actin filaments alone do not stimulate the short pitch conformational change. In contrast, contacts with the mother filament stabilize subunit flattening in Arp3, an intrasubunit change that converts Arp3 from a conformation that mimics an actin monomer to one that mimics a filamentous actin subunit. Our results support a multistep activation pathway that has important implications for understanding how WASP-mediated activation allows Arp2/3 complex to assemble force-producing actin networks.


Subject(s)
Actin Cytoskeleton , Actin-Related Protein 2-3 Complex , Actin Cytoskeleton/genetics , Actin Cytoskeleton/metabolism , Actin-Related Protein 2-3 Complex/metabolism , Molecular Dynamics Simulation , Protein Structure, Quaternary , Animals , Cattle
3.
Soft Matter ; 20(36): 7122-7132, 2024 Sep 18.
Article in English | MEDLINE | ID: mdl-39193982

ABSTRACT

Understanding and control of the effective interaction between nanoscale building blocks (colloids or nanoparticles) dispersed in a solvent is an important prerequisite for the development of bottom-up design strategies for soft functional materials. Here, we have employed all-atom molecular dynamics simulations to investigate the impact of polymer grafting on the solvent-mediated effective interaction between the silica nanoparticles (Si-NPs) in water, and in turn, on its bulk structural and thermodynamic properties. We found that the nature of the short grafting polymers [characterized by their interaction with water (hydrophobicity or hydrophilicity) and molecular weight] has a profound effect on the range and strength of the effective interaction between the Si-NPs. The hydrophobic polymer [such as polyethylene (PE)]-grafting of Si-NP gives rise to a more attractive interaction between the Si-NPs compared to the hydrophilic polymer [such as polyethylene glycol (PEG)] and non-grafted cases. This study further provides fundamental insights into the molecular origin of the observed behavior of the effective pair interactions between the grafted Si-NPs. For PE-grafted Si-NPs, the confined water (water inside the cavity formed by a pair of Si-NPs) undergoes a partial dewetting transition on approaching below a critical inter-particle separation leading to a stronger attractive interaction. Furthermore, we report that the effective attraction between the PE-grafted Si-NPs can be reliably controlled by changing the grafting PE density. We have also investigated the bulk structural and thermodynamic behavior of the coarse-grained Si-NP system where the particles interact via effective interaction in the absence of water. We believe that the insights gained from this work are important prerequisites for formulating rational bottom-up design strategies for functional materials where nano- (or, colloidal) particles are the building blocks.

4.
Anesth Analg ; 134(2): 303-311, 2022 02 01.
Article in English | MEDLINE | ID: mdl-34469334

ABSTRACT

BACKGROUND: Oxytocin administration during cesarean delivery is the first-line therapy for the prevention of uterine atony. Patients with preeclampsia may receive magnesium sulfate, a drug with known tocolytic effects, for seizure prophylaxis. However, no study has evaluated the minimum effective dose of oxytocin during cesarean delivery in women with preeclampsia. METHODS: This study compared the effective dose in 90% population (ED90) of oxytocin infusion for achieving satisfactory uterine tone during cesarean delivery in nonlaboring patients with preeclampsia who were receiving magnesium sulfate treatment with a control group of normotensives who were not receiving magnesium sulfate. This prospective dual-arm dose-finding study was based on a 9:1 biased sequential allocation design. Oxytocin infusion was initiated at 13 IU/h, on clamping of the umbilical cord, in the first patient of each group. Uterine tone was graded as satisfactory or unsatisfactory by the obstetrician at 4 minutes after initiation of oxytocin infusion. The dose of oxytocin infusion for subsequent patients was decided according to the response exhibited by the previous patient in the group; it was increased by 2 IU/h after unsatisfactory response or decreased by 2 IU/h or maintained at the same level after satisfactory response, in a ratio of 1:9. Oxytocin-associated side effects were also evaluated. Dose-response data for the groups were evaluated using a log-logistic function and ED90 estimates were derived from fitted equations using the delta method. RESULTS: The ED90 of oxytocin was significantly greater for the preeclampsia group (n = 27) than for the normotensive group (n = 40) (24.9 IU/h [95% confidence interval {CI}, 22.4-27.5] and 13.9 IU/h [95% CI, 12.4-15.5], respectively); the difference in dose requirement was 10.9 IU/h (95% CI, 7.9-14.0; P < .001). The number of patients with oxytocin-related hypotension, defined as a decrease in systolic blood pressure >20% from baseline or to <90 mm Hg, was significantly greater in the preeclampsia group (92.6% vs 62.5%; P = .030), while other side effects such as ST-T depression, nausea/vomiting, headache, and flushing, were not significantly different. There was no significant difference in the need for additional uterotonic or uterine massage, estimated blood loss, and need for re-exploration for uncontrolled bleeding. CONCLUSIONS: Patients with preeclampsia receiving preoperative magnesium therapy need a greater intraoperative dose of oxytocin to achieve satisfactory contraction of the uterus after fetal delivery, as compared to normotensives.


Subject(s)
Analgesics/administration & dosage , Cesarean Section/methods , Magnesium Sulfate/administration & dosage , Oxytocin/administration & dosage , Pre-Eclampsia/drug therapy , Pre-Exposure Prophylaxis/methods , Adult , Blood Pressure/drug effects , Blood Pressure/physiology , Cesarean Section/adverse effects , Dose-Response Relationship, Drug , Female , Humans , Infusions, Intravenous , Pre-Eclampsia/diagnosis , Pre-Eclampsia/epidemiology , Pregnancy , Prospective Studies , Treatment Outcome , Young Adult
5.
Genome ; 64(4): 355-371, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33031715

ABSTRACT

The gut-brain axis (GBA) is a biochemical link that connects the central nervous system (CNS) and enteric nervous system (ENS). Clinical and experimental evidence suggests gut microbiota as a key regulator of the GBA. Microbes living in the gut not only interact locally with intestinal cells and the ENS but have also been found to modulate the CNS through neuroendocrine and metabolic pathways. Studies have also explored the involvement of gut microbiota dysbiosis in depression, anxiety, autism, stroke, and pathophysiology of other neurodegenerative diseases. Recent reports suggest that microbe-derived metabolites can influence host metabolism by acting as epigenetic regulators. Butyrate, an intestinal bacterial metabolite, is a known histone deacetylase inhibitor that has shown to improve learning and memory in animal models. Due to high disease variability amongst the population, a multi-omics approach that utilizes artificial intelligence and machine learning to analyze and integrate omics data is necessary to better understand the role of the GBA in pathogenesis of neurological disorders, to generate predictive models, and to develop precise and personalized therapeutics. This review examines our current understanding of epigenetic regulation of the GBA and proposes a framework to integrate multi-omics data for prediction, prevention, and development of precision health approaches to treat brain disorders.


Subject(s)
Brain Diseases/genetics , Epigenesis, Genetic , Gastrointestinal Microbiome/physiology , Machine Learning , Animals , Artificial Intelligence , Bacteria/genetics , Brain , Data Analysis , Dysbiosis , Fatty Acids, Volatile , Humans
6.
Eur Spine J ; 30(4): 1004-1010, 2021 04.
Article in English | MEDLINE | ID: mdl-32914232

ABSTRACT

BACKGROUND: Among non-communicable disorders, low back and neck pain are the most common causes of severe, long-term pain and disability affecting more than a billion people globally. Yet, the burden and impact of these conditions are not well understood, especially among rural and tribal people living in low- and middle-income countries. OBJECTIVE: The aims of this study were to measure point prevalence of low back and neck pain among rural and tribal people in Raigad District of Maharashtra, India, and explore attitudes and beliefs of rural people towards spine pain and disability. DESIGN: In a cross-sectional survey of six villages in the Raigad District of Maharashtra State of India from August to October 2016, low back and neck pain were measured using the Spine Pain Questionnaire. RESULTS: We surveyed 2323 participants, which did not include children and adolescents. Among rural people (n = 2073), the point prevalence of low back and neck pain was 4.9% (95% CI 3.94-5.79) and 2.9% (95% CI 2.21-8.87), respectively. Among tribal people (n = 250), prevalence was 10.0% (95% CI 6.28-13.71) for low back pain and 3.6% (95% CI 1.29-5.90) for neck pain. Lifting heavy weights and bending trunk were the most limiting activities. During informal discussions, most villagers attributed spine pain to traditional lifestyle and age. Participants continued occupational work in the presence of pain. Lack of transport facilities and cost of treatment emerged as the two most common reasons for delay in seeking treatment at nearby healthcare centres. This information will inform the development of customized spine care programmes through community-engaged partnerships and self-empowerment of the local community.


Subject(s)
Low Back Pain , Rural Population , Adolescent , Child , Cross-Sectional Studies , Humans , India , Neck Pain
7.
J Chem Phys ; 152(24): 244120, 2020 Jun 28.
Article in English | MEDLINE | ID: mdl-32610977

ABSTRACT

Many proteins in cells are capable of sensing and responding to piconewton-scale forces, a regime in which conformational changes are small but significant for biological processes. In order to efficiently and effectively sample the response of these proteins to small forces, enhanced sampling techniques will be required. In this work, we derive, implement, and evaluate an efficient method to simultaneously sample the result of applying any constant pulling force within a specified range to a molecular system of interest. We start from simulated tempering in force, whereby force is added as a linear bias on a collective variable to the system's Hamiltonian, and the coefficient is taken as a continuous auxiliary degree of freedom. We derive a formula for an average collective-variable-dependent force, which depends on a set of weights learned on-the-fly throughout a simulation, that reflect the limit where force varies infinitely quickly. Simulation data can then be used to retroactively compute averages of any observable at any force within the specified range. This technique is based on recent work deriving similar equations for infinite switch simulated tempering in temperature, which showed that the infinite switch limit is the most efficient for sampling. Here, we demonstrate that our method accurately samples molecular systems at all forces within a user defined force range simultaneously and show how it can serve as an enhanced sampling tool for cases where the pulling direction destabilizes states that have low free-energy at zero-force. This method is implemented in and freely distributed with the PLUMED open-source sampling library, and hence can be readily applied to problems using a wide range of molecular dynamics software packages.


Subject(s)
Peptides/chemistry , Algorithms , Mechanical Phenomena , Molecular Dynamics Simulation , Proof of Concept Study
8.
AAPS PharmSciTech ; 21(8): 313, 2020 Nov 09.
Article in English | MEDLINE | ID: mdl-33165766

ABSTRACT

A solid self-emulsifying drug delivery system (SEDDS) of paclitaxel (PTX) was developed that could enhance its oral bioavailability and neutralize other niggles associated with conventional delivery systems of PTX. TPGS-centered SEDDS containing PTX was optimized by Box-Behnken experimental design and then formulated as fumed colloidal silica-based solid SEDDS microparticles (Si-PTX-S-SEDDS). AFM analysis exhibited round-shaped microparticles of approximately 2-3 µM diameter, whereas after reconstitution, particle size measurement showed nanoemulsion droplets of 30.00 ± 2.00 nm with a zeta potential of 17.38 ± 2.88 mV. Si-PTX-S-SEDDS displayed improved efficacy proven by reduced IC50 of 0.19 ± 0.03 µM against MDA-MB-231 cells and a 45.83-fold higher cellular uptake in comparison to free PTX. Molecular mechanistic studies showed mitochondria-mediated intrinsic pathway of apoptosis following Akt/mTOR pathway, which is accompanied by survivin downregulation. Rhodamine 123 assay and chylomicron flow blocking studies revealed P-gp inhibition potential and lymphatic uptake of Si-PTX-S-SEDDS, responsible for over 4-fold increment in oral bioavailability compared to PTX administered as Taxol. In vivo anti-tumor studies in syngeneic mammary tumor model in SD rats revealed higher efficacy of Si-PTX-S-SEDDS as evident from significant reduction in tumor burden. In total, the developed Si-PTX-S-SEDDS formulation was found as an appropriate option for oral delivery of PTX.


Subject(s)
Antineoplastic Agents, Phytogenic/administration & dosage , Colloids/chemistry , Mammary Neoplasms, Animal/drug therapy , Paclitaxel/administration & dosage , Proto-Oncogene Proteins c-akt/metabolism , Silicon Dioxide/chemistry , TOR Serine-Threonine Kinases/metabolism , Vitamin E/chemistry , Animals , Antineoplastic Agents, Phytogenic/chemistry , Apoptosis/drug effects , Biological Availability , Cell Line, Tumor , Drug Delivery Systems , Emulsions/pharmacology , Humans , Paclitaxel/chemistry , Rats , Rats, Sprague-Dawley , Research Design
9.
Mol Pharm ; 16(9): 3744-3759, 2019 09 03.
Article in English | MEDLINE | ID: mdl-31441308

ABSTRACT

We have devised a nanocarrier using "tocopheryl polyethylene glycol succinate (TPGS) conjugated to triphenylphosphonium cation" (TPP-TPGS) for improving the efficacy of doxorubicin hydrochloride (DOX). Triphenylphosphonium cation (TPP) has affinity for an elevated transmembrane potential gradient (mitochondrial), which is usually high in cancer cells. Consequently, when tested in molecular docking and cytotoxicity assays, TPP-TPGS, owing to its structural similarity to mitochondrially directed anticancer compounds of the "tocopheryl succinate" family, interferes specifically in mitochondrial CII enzyme activity, increases intracellular oxidative stress, and induces apoptosis in breast cancer cells. DOX loaded nanocarrier (DTPP-TPGS) constructed using TPP-TPGS was positively charged, spherical in shape, sized below 100 nm, and had its drug content distributed evenly. DTPP-TPGS offers greater intracellular drug delivery due to its rapid endocytosis and subsequent endosomal escape. DTPP-TPGS also efficiently inhibits efflux transporter P glycoprotein (PgP), which, along with greater cell uptake and inherent cytotoxic activity of the construction material (TPP-TPGS), cumulatively results in 3-fold increment in anticancer activity of DOX in resistant breast cancer cells as well as greater induction of necroapoptosis and arrest in all phases of the cell cycle. DTPP-TPGS after intravenous administration in Balb/C mice with breast cancer accumulates preferentially in tumor tissue, which produces significantly greater antitumor activity when compared to DOX solution. Toxicity evaluation was also performed to confirm the safety of this formulation. Overall TPP-TPGS is a promising candidate for delivery of DOX.


Subject(s)
Antibiotics, Antineoplastic/therapeutic use , Apoptosis/drug effects , Breast Neoplasms/drug therapy , Doxorubicin/therapeutic use , Drug Carriers/chemistry , Drug Delivery Systems/methods , Drug Resistance, Neoplasm/drug effects , Mitochondria/metabolism , Vitamin E/chemistry , Animals , Antibiotics, Antineoplastic/chemistry , Antibiotics, Antineoplastic/pharmacokinetics , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Disease Models, Animal , Doxorubicin/chemistry , Doxorubicin/pharmacokinetics , Drug Carriers/pharmacokinetics , Female , Humans , MCF-7 Cells , Membrane Potential, Mitochondrial/drug effects , Mice , Mice, Inbred BALB C , Molecular Docking Simulation , Reactive Oxygen Species/metabolism , Tissue Distribution , Vitamin E/pharmacokinetics
10.
Mol Pharm ; 14(8): 2749-2765, 2017 08 07.
Article in English | MEDLINE | ID: mdl-28636400

ABSTRACT

PLGA was functionalized with PEG and biotin using click chemistry to generate a biotin receptor targeted copolymer (biotinylated-PEG-PLGA) which in turn was used to fabricate ultrafine nanoparticles (BPNP) of doxorubicin hydrochloride (DOX) for effective delivery in 4T1 cell induced breast cancer. However, adequate entrapment of a hydrophilic bioactive like DOX in a hydrophobic polymer system made of PLGA is not usually possible. We therefore modified a conventional W/O/W emulsion method by utilizing NH4Cl in the external phase to constrain DOX in dissolved polymer phase by suppressing DOX's inherent aqueous solubility as per common ion effect. This resulted in over 8-fold enhancement in entrapment efficiency of DOX inside BPNP, which otherwise is highly susceptible to leakage due to its relatively high aqueous solubility. TEM and DLS established BPNP to be sized below 100 nm, storage stability studies showed that BPNP were stable for one month at 4 °C, and in vitro release suggested significant control in drug release. Extensive in vitro and in vivo studies were conducted to propound anticancer and antiproliferative activity of BPNP. Plasma and tissue distribution study supplemented by pertinent in vivo fluorescence imaging mapped the exact fate of DOX contained inside BPNP once it was administered intravenously. A comparative safety profile via acute toxicity studies in mice was also generated to out rightly establish usefulness of BPNP. Results suggest that BPNP substantially enhance anticancer activity of DOX while simultaneously mitigating its toxic potential due to altered spatial and temporal presentation of drug and consequently deserve further allometric iteration.


Subject(s)
Doxorubicin/chemistry , Nanoparticles/chemistry , Polyesters/chemistry , Polyethylene Glycols/chemistry , Receptors, Growth Factor/chemistry , Biotinylation , Click Chemistry/methods
11.
Pharm Res ; 34(9): 1857-1871, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28608139

ABSTRACT

OBJECTIVE: To utilize nanoparticles produced by condensation of zymosan (an immunotherapeutic polysaccharide) with pegylated polyethylenimine (PEG-PEI) for dual intervention in breast cancer by modulating tumor microenvironment and direct chemotherapy. METHOD: Positively charged PEG-PEI and negatively charged sulphated zymosan were utilized for electrostatic complexation of chemoimmunotherapeutic nanoparticles (ChiNPs). ChiNPs were loaded with doxorubicin hydrochloride (DOX) for improved delivery at tumor site and were tested for in-vivo tolerability. Biodistribution studies were conducted to showcase their effective accumulation in tumor hypoxic regions where tumor associated macrophages (TAMs) are preferentially recruited. RESULTS: ChiNPs modulated TAMs differentiation resulting in decrement of CD206 positive population. This immunotherapeutic action was furnished by enhanced expression of Th1 specific cytokines. ChiNPs also facilitated an anti-angiogenetic effect which further reduces the possibility of tumor progression and metastasis.


Subject(s)
Antibiotics, Antineoplastic/therapeutic use , Breast Neoplasms/drug therapy , Doxorubicin/therapeutic use , Drug Carriers/chemistry , Immunologic Factors/therapeutic use , Nanoparticles/chemistry , Zymosan/therapeutic use , Animals , Antibiotics, Antineoplastic/administration & dosage , Antibiotics, Antineoplastic/pharmacokinetics , Breast/drug effects , Breast/immunology , Breast/pathology , Breast Neoplasms/immunology , Breast Neoplasms/pathology , Cell Proliferation/drug effects , Cytokines/immunology , Doxorubicin/administration & dosage , Doxorubicin/pharmacokinetics , Drug Delivery Systems , Female , Immunologic Factors/administration & dosage , Immunologic Factors/pharmacokinetics , Macrophages/drug effects , Macrophages/immunology , Mice, Inbred BALB C , Polyethyleneimine/chemistry , Static Electricity , Tissue Distribution , Zymosan/administration & dosage , Zymosan/pharmacokinetics
12.
Mol Pharm ; 13(6): 2084-94, 2016 06 06.
Article in English | MEDLINE | ID: mdl-27144397

ABSTRACT

Systemic chemotherapeutic targeting of filarial parasites is unfocused due to their deep seated location in lymphatic vessels. This warrants a prolonged dosing regimen in high doses for an anthelmintic like doxycycline hydrochloride (DOX). In order to provide an alternative, we have constructed ultrafine PLGA nanoparticles of DOX (DPNPs), so as to exploit the peculiarity of lymphatic vasculature underneath the subcutaneous layer of skin, which preferentially allows entry of only 10-100 nm sized particles. DPNPs were constructed using a novel solvent diffusion method aided by probe sonication, which resulted in an average size 95.43 ± 0.8 nm as per DLS, PDI 0.168 ± 0.03, zeta potential -7.38 ± 0.32, entrapment efficiency 75.58 ± 1.94%, and refrigerator stability of 7 days with respect to size in the optimized batch. TEM further substantiated the spherical shape of DPNPs along with their actual nonhydrated size as being well below 100 nm. FTIR analysis of DOX, dummy nanoparticles, and freeze-dried DPNPs revealed that the formulation step did not induce prominent changes in the chemical nature of DOX. The drug release was significantly altered (p < 0.05) with 64.6 ± 1.67% release in 48 h from DPNPs and was dictated by Fickian diffusion. Pharmacokinetic studies in Wistar rats further revealed that DPNPs caused a 16-fold prolongation in attainment of plasma Tmax and a 2-fold extension of elimination half-life (28.569 ± 1.27 h) at a dose of 5 mg/kg when compared to native drug (DOX solution) of the same strength. Contrastingly the trend was reversed in regional lymph nodes where Cmax for DPNPs (820 ± 84 ng/mg) was 4-fold greater, and lymphatic Tmax was attained in one-fourth of what was required for DOX solution. This size based preferential lymphatic targeting resulted in significantly greater in vivo antifilarial activity of DPNPs when compared to DOX solution as gauged by several parameters in Brugia malayi infected Mastomys coucha. Interestingly, the magnification in efficacy was obtained despite equivalent in vitro antifilarial activity of DOX solution and DPNPs against B. malayi worms.


Subject(s)
Doxycycline/administration & dosage , Elephantiasis, Filarial/drug therapy , Lactic Acid/administration & dosage , Nanoparticles/administration & dosage , Parasites/drug effects , Polyglycolic Acid/administration & dosage , Silicones/administration & dosage , Administration, Cutaneous , Animals , Brugia malayi/drug effects , Drug Liberation , Half-Life , Male , Particle Size , Particulate Matter , Polylactic Acid-Polyglycolic Acid Copolymer , Rats , Rats, Wistar
13.
J Nanosci Nanotechnol ; 16(4): 4180-90, 2016 Apr.
Article in English | MEDLINE | ID: mdl-27451784

ABSTRACT

Although curcumin (Cur), has been poised to be an anticancer boon for quite some, its progress from bench to bed has been strained due to various pharmaceutical hurdles. Consequently curcumin has been entrapped in methoxy poly ethylene glycol and linoleic acid conjugated polymeric micelles (PMs) to not only tackle the routine issues but to also provide a synergetic effect against MCF-7 breast cancer cells. Optimized PMs of Cur had size 186.53 ± 12.10 nm with polydispersity index 0.143 ± 0.031 and zeta potential -30.1 ± 3.2 mV. Developed formulation (Mpeg-Cla-Cur PMs) was hemocompatible and had high cytotoxicity (IC50 55.80 ± 4.63 µ/mL) against MCF-7 cells in comparison to pure Cur suspension (IC50 75.05 ± 5.75 µg/mL). As postulated cell cycle arrest and apoptosis studies revealed synergetic effect of Mpeg-Cla-Cur PMs with higher cell population in G1 phase in addition to high apoptosis of MCF-7 cells as compared to pure Cur suspension and con- trol group. Pharmacokinetic studies also show PMs enhanced MRT and T1/2 of Cur indicating its longer retention time in body. Mpeg-Cla-Cur PMs might become as an excellent chemotherapeutic alternative candidate for treatment of breast cancer with higher commercial value.


Subject(s)
Apoptosis/drug effects , Cell Survival/drug effects , Curcumin/administration & dosage , Linoleic Acid/chemistry , Nanocapsules/chemistry , Polyethylene Glycols/chemistry , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/chemistry , Curcumin/chemistry , Diffusion , Drug Synergism , Humans , MCF-7 Cells , Nanocapsules/administration & dosage
14.
J Microencapsul ; 32(1): 75-85, 2015.
Article in English | MEDLINE | ID: mdl-25198910

ABSTRACT

This work demonstrates Box-Behnken design (BBD)'s capability in exploring scientific principles governing a process, different from its use in process optimisation. We have investigated nanoprecipitation (NP) of temozolomide with polycaprolactone. Five factors, surfactant, stirring speed (SS), dropping rate (DR), phase-volume ratio (PVR) and drug-polymer ratio (DPR) were varied over three levels. Corresponding particle size (238.9 ± 42.24 nm), zeta potential (ZP, -5.92 ± 3.15 mV), poly dispersity index (PDI, 0.176 ± 0.06) and entrapment efficiency (EE, 65.74 ± 9.83%) were put into different polynomial equations. Analysis of variance, lack of fit tests and regression analysis was applied on these equations to determine the one with best fit. This selected equation was subsequently adapted as the model to describe influence of factors on NP. 3D response surface plots corresponding to models and diagnostic plots relatable to normality of residuals were also constructed. In conclusion, application of BBD efficiently strategised experimental foray conducted to elucidate NP.


Subject(s)
Dacarbazine/analogs & derivatives , Models, Chemical , Polyesters/chemistry , Surface-Active Agents/chemistry , Dacarbazine/chemistry , Temozolomide
15.
J Phys Chem B ; 128(3): 706-715, 2024 Jan 25.
Article in English | MEDLINE | ID: mdl-38230998

ABSTRACT

Small mechanical forces play important functional roles in many crucial cellular processes, including in the dynamic behavior of the cytoskeleton and in the regulation of osmotic pressure through membrane-bound proteins. Molecular simulations offer the promise of being able to design the behavior of proteins that sense and respond to these forces. However, it is difficult to predict and identify the effect of the relevant piconewton (pN) scale forces due to their small magnitude. Previously, we introduced the Infinite Switch Simulated Tempering in Force (FISST) method, which allows one to estimate the effect of a range of applied forces from a single molecular dynamics simulation, and also demonstrated that FISST additionally accelerates sampling of a molecule's conformational landscape. For some problems, we find that this acceleration is not sufficient to capture all relevant conformational fluctuations, and hence, here we demonstrate that FISST can be combined with either temperature replica exchange or solute tempering approaches to produce a hybrid method that enables more robust prediction of the effect of small forces on molecular systems.


Subject(s)
Molecular Dynamics Simulation , Proteins , Molecular Conformation , Temperature
16.
Eur J Pharmacol ; 982: 176902, 2024 Nov 05.
Article in English | MEDLINE | ID: mdl-39153648

ABSTRACT

AIM: The current study explores niclosamide's neuroprotective potential in an animal model of autism spectrum disorder (ASD) and goes further to understand how the ERK/MAPK signaling pathway is thought to contribute to this activity. METHODS: In order to create an autism-like phenotype in rats, 4 µl of 1 M PPA was infused intracerebroventricularly. The oral treatment with niclosamide (50 and 100 mg/kg) and risperidone (1 mg/kg) (used as standard) was given from 3rd to 30th day. Between the 14th and 28th day, behavioral assessments were made for sociability, stereotypy, anxiety, depression, novelty preference, repetitive behavior, and perseverative behavior. The animals were euthanized on the 29th day, and oxidative stress markers were assessed in the brain homogenate. The levels of neuroinflammatory cytokines such as TNF-α, IL-6, NF-κB, IFN-γ and glutamate were estimated using ELISA kits. To assess the involvement of the ERK/MAPK signaling pathway, levels of Nrf2 and ERK2 were also measured. KEY FINDINGS: Niclosamide therapy significantly restored behavioral, biochemical, neurological, and molecular impairments. Hence, niclosamide could be a potential neurotherapeutic candidate for further studies for use in ASD.


Subject(s)
Autism Spectrum Disorder , Behavior, Animal , Disease Models, Animal , Drug Repositioning , MAP Kinase Signaling System , Niclosamide , Animals , Niclosamide/pharmacology , Niclosamide/therapeutic use , Autism Spectrum Disorder/drug therapy , Autism Spectrum Disorder/metabolism , MAP Kinase Signaling System/drug effects , Rats , Male , Behavior, Animal/drug effects , Rats, Wistar , Anthelmintics/pharmacology , Anthelmintics/therapeutic use , Oxidative Stress/drug effects , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Cytokines/metabolism , NF-E2-Related Factor 2/metabolism , Brain/drug effects , Brain/metabolism
17.
Biochem Pharmacol ; 222: 116074, 2024 04.
Article in English | MEDLINE | ID: mdl-38395265

ABSTRACT

Olanzapine, a widely prescribed atypical antipsychotic, poses a great risk to the patient's health by fabricating a plethora of severe metabolic and cardiovascular adverse effects eventually reducing life expectancy and patient compliance. Its heterogenous receptor binding profile has made it difficult to point out a specific cause or treatment for the related side effects. Growing body of evidence suggest that transient receptor potential (TRP) channel subfamily Ankyrin 1 (TRPA1) has pivotal role in pathogenesis of type 2 diabetes and obesity. With this background, we aimed to investigate the role of pharmacological manipulations of TRPA1 channels in antipsychotic (olanzapine)-induced metabolic alterations in female mice using allyl isothiocyanate (AITC) and HC-030031 (TRPA1 agonist and antagonist, respectively). It was found that after 6 weeks of treatment, AITC prevented olanzapine-induced alterations in body weight and adiposity; serum, and liver inflammatory markers; glucose and lipid metabolism; and hypothalamic appetite regulation, nutrient sensing, inflammatory and TRPA1 channel signaling regulating genes. Furthermore, several of these effects were absent in the presence of HC-030031 (TRPA1 antagonist) indicating protective role of TRPA1 agonism in attenuating olanzapine-induced metabolic alterations. Supplementary in-depth studies are required to study TRPA1 channel effect on other aspects of olanzapine-induced metabolic alterations.


Subject(s)
Acetanilides , Antipsychotic Agents , Diabetes Mellitus, Type 2 , Purines , Transient Receptor Potential Channels , Mice , Humans , Female , Animals , TRPA1 Cation Channel , Olanzapine , Antipsychotic Agents/toxicity , Isothiocyanates/pharmacology , Obesity/chemically induced , Obesity/drug therapy , Liver/metabolism
18.
Expert Opin Drug Deliv ; 21(4): 639-662, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38703363

ABSTRACT

INTRODUCTION: Novel injectables possess applications in both local and systemic therapeutics delivery. The advancement in utilized materials for the construction of complex injectables has tremendously upgraded their safety and efficacy. AREAS COVERED: This review focuses on various strategies to produce novel injectables, including oily dispersions, in situ forming implants, injectable suspensions, microspheres, liposomes, and antibody-drug conjugates. We herein present a detailed description of complex injectable technologies and their related drug formulations permitted for clinical use by the United States Food and Drug Administration (USFDA). The excipients used, their purpose and the challenges faced during manufacturing such formulations have been critically discussed. EXPERT OPINION: Novel injectables can deliver therapeutic agents in a controlled way at the desired site. However, several challenges persist with respect to their genericization. Astronomical costs incurred by innovator companies during product development, complexity of the product itself, supply limitations with respect to raw materials, intricate manufacturing processes, patent evergreening, product life-cycle extensions, relatively few and protracted generic approvals contribute to the exorbitant prices and access crunch. Moreover, regulatory guidance are grossly underdeveloped and significant efforts have to be directed toward development of effective characterization techniques.


Subject(s)
Drug Approval , Drug Delivery Systems , Injections , United States Food and Drug Administration , Humans , United States , Drug Development , Drug Compounding , Excipients/chemistry , Pharmaceutical Preparations/administration & dosage , Animals , Chemistry, Pharmaceutical
19.
ArXiv ; 2023 Oct 18.
Article in English | MEDLINE | ID: mdl-37904741

ABSTRACT

Small mechanical forces play important functional roles in many crucial cellular processes, including in the dynamical behavior of the cytoskeleton and in the regulation of osmotic pressure through membrane-bound proteins. Molecular simulations offer the promise of being able to design the behavior of proteins that sense and respond to these forces. However, it is difficult to predict and identify the effect of the relevant piconewton (pN) scale forces due to their small magnitude. Previously, we introduced the Infinite Switch Simulated Tempering in Force (FISST) method which allows one to estimate the effect of a range of applied forces from a single molecular dynamics simulation, and also demonstrated that FISST additionally accelerates sampling of a molecule's conformational landscape. For some problems, we find that this acceleration is not sufficient to capture all relevant conformational fluctuations, and hence here we demonstrate that FISST can be combined with either temperature replica exchange or solute tempering approaches to produce a hybrid method that enables more robust prediction of the effect of small forces on molecular systems.

20.
J Phys Chem B ; 127(14): 3312-3324, 2023 Apr 13.
Article in English | MEDLINE | ID: mdl-36989467

ABSTRACT

In contrast to the abundance of work on the anomalous behavior of water, the relationship between the water's thermodynamic anomalies and kinetics of phase transition from metastable water is relatively unexplored. In this work, we have employed classical density functional theory to provide a unified and coherent picture of nucleation (both vapor and ice) from metastable water at negative pressure conditions. Our results suggest a peculiar nonmonotonic temperature dependence of vapor-liquid surface tension at temperatures where vapor-liquid coexistence is metastable with respect to the ice phase. The vapor nucleation barrier on isochoric cooling also shows a nonmonotonic temperature dependence. We further report that, for low density isochores, the temperature of the minimum vapor nucleation barrier (TΔΩv/min*) does not coincide with the temperature of maximum density (TMD) where metastability is maximum. The difference between the TΔΩv/min* and the TMD, however, decreases with increasing the density of the isochore. The vapor nucleation barrier along isobars shows an interesting crossover behavior in the vicinity of the Widom line on lowering the temperature. Our results on the ice nucleation suggest an anomalous retracing behavior of the nucleation barrier along isotherms at negative pressures and theoretically validate the recent findings that the reentrant ice(Ih)-liquid coexistence line can induce a drastic change in the kinetics of ice nucleation. Thus, this study establishes a direct connection between the metastable water's thermodynamic anomalies and the (vapor and ice) nucleation kinetics. In addition, this study provides deeper insights into the origin of the isothermal compressibility maximum on isochoric cooling.

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