Sublethal Toxicity of 17 Per- and Polyfluoroalkyl Substances with Diverse Structures to Ceriodaphnia dubia, Hyalella azteca, and Chironomus dilutus.

Seven-day sublethal toxicity tests were performed with the freshwater invertebrates Ceriodaphnia dubia, Hyalella azteca, and Chironomus dilutus to determine the effects of per- or polyfluorinated alkyl substances (PFAS) of varying chain length within four classes: perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs), perfluoroalkane sulfonamides, and fluorotelomer sulfonic acids. In general, toxicity increased with increasing chain length, but the slopes of these relationships varied markedly by species and chemical class. The toxicity of individual PFCAs was similar among species. The toxicity of PFSAs was similar to PFCAs for C. dubia and H. azteca, whereas PFSAs were much more toxic to C. dilutus, with median effect concentrations (EC50s) as low as 0.022 mg perfluorooctane sulfonate (PFOS)/L and 0.012 mg perfluorononane sulfonate (PFNS)/L. Despite the high sensitivity to PFOS and PFNS, C. dilutus was not very sensitive to structurally similar fluorotelomer sulfonates (6:2 and 8:2). Perfluoroalkane sulfonamides were the most toxic class tested among all species (e.g., EC50s of 0.011 and 0.017 mg perfluorooctane sulfonamide/L for C. dilutus and H. azteca, respectively). The differences in toxicity among species and chemical classes suggest that mechanisms of PFAS toxicity may differ as a function of both. Environ Toxicol Chem 2024;43:359-373. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

Evaluating the Effect of Gestational Exposure to Perfluorohexane Sulfonate on Placental Development in Mice Combining Alternative Splicing and Gene Expression Analyses.

BACKGROUND: Perfluorohexane sulfonate (PFHxS) is a frequently detected per- and polyfluoroalkyl substance in most populations, including in individuals who are pregnant, a period critical for early life development. Despite epidemiological evidence of exposure, developmental toxicity, particularly at realistic human exposures, remains understudied. OBJECTIVES: We evaluated the effect of gestational exposure to human-relevant body burden of PFHxS on fetal and placental development and explored mechanisms of action combining alternative splicing (AS) and gene expression (GE) analyses. METHODS: Pregnant ICR mice were exposed to 0, 0.03, and 0.3µg/kg/day from gestational day 7 to day 17 via oral gavage. Upon euthanasia, PFHxS distribution was measured using liquid chromatography-tandem mass spectrometry. Maternal and fetal phenotypes were recorded, and histopathology was examined for placenta impairment. Multiomics was adopted by combining AS and GE analyses to unveil disruptions in mRNA quality and quantity. The key metabolite transporters were validated by quantitative real-time PCR (qRT-PCR) for quantification and three-dimensional (3D) structural simulation by AlphaFold2. Targeted metabolomics based on liquid chromatography-tandem mass spectrometry was used to detect amino acid and amides levels in the placenta. RESULTS: Pups developmentally exposed to PFHxS exhibited signs of intrauterine growth restriction (IUGR), characterized by smaller fetal weight and body length (p<0.01) compared to control mice. PFHxS concentration in maternal plasma was 5.01±0.54 ng/mL. PFHxS trans-placenta distribution suggested dose-dependent transfer through placental barrier. Histopathology of placenta of exposed dams showed placental dysplasia, manifested with an attenuated labyrinthine layer area and deescalated blood sinus counts and placental vascular development index marker CD34. Combined GE and AS analyses pinpointed differences in genes associated with key biological processes of placental development, proliferation, metabolism, and transport in placenta of exposed dams compared to that of control dams. Further detection of placental key transporter gene expression, protein structure simulation, and amino acid and amide metabolites levels suggested that PFHxS exposure during pregnancy led to impairment of placental amino acid transportation. DISCUSSION: The findings from this study suggest that exposure to human-relevant very-low-dose PFHxS during pregnancy in mice caused IUGR, likely via downregulating of placental amino acid transporters, thereby impairing placental amino acid transportation, resulting in impairment of placental development. Our findings confirm epidemiological findings and call for future attention on the health risk of this persistent yet ubiquitous chemical in the early developmental stage and provide a new approach for understanding gene expression from both quantitative and qualitative omics approaches in toxicological studies. https://doi.org/10.1289/EHP13217.

Novel anti-Acanthamoebic properties of raloxifene sulfonate/sulfamate derivatives.

Acanthamoeba are known to cause a vision threatening eye infection typically due to contact lens wear, and an infection of the central nervous system. The ability of these amoebae to switch phenotypes, from an active trophozoite to a resistant cyst form is not well understood; the cyst stage is often resistant to chemotherapy, which is of concern given the rise of contact lens use and the ineffective disinfectants available, versus the cyst stage. Herein, for the first time, a range of raloxifene sulfonate/sulfamate derivatives which target nucleotide pyrophosphatase/phosphodiesterase enzymes, were assessed using amoebicidal and excystation tests versus the trophozoite and cyst stage of Acanthamoeba. Moreover, the potential for cytopathogenicity inhibition in amoebae was assessed. Each of the derivatives showed considerable anti-amoebic activity as well as the ability to suppress phenotypic switching (except for compound 1a). Selected raloxifene derivatives reduced Acanthamoeba-mediated host cell damage using lactate dehydrogenase assay. These findings suggest that pyrophosphatase/phosphodiesterase enzymes may be valuable targets against Acanthamoeba infections.

Reproductive and immune effects emerge at similar thresholds of PFHxS in deer mice.

Although perfluorohexane sulfonate (PFHxS) is structurally similar to perfluorooctane sulfonate (PFOS) and also widely detected in humans and the environment, comparatively fewer toxicity data exists on this 6-chain perfluoroalkyl sulfonic acid. In this study, repeated oral doses of PFHxS were administered to deer mice (Peromyscus maniculatus) to evaluate subchronic toxicity and potential effects on reproduction and development. Maternal oral exposure to PFHxS caused increased stillbirths, which is relevant for ecological risk assessment, and resulted in a benchmark dose lower limit (BMDL) of 5.72 mg/kg-d PFHxS. Decreased plaque formation, which is relevant for human health risk assessment, occurred in both sexes of adult animals (BMDL = 8.79 mg/kg-d PFHxS). These data are the first to suggest a direct link between PFHxS and decreased functional immunity in an animal model. Additionally, female animals exhibited increased liver:body weight and animals of both sexes exhibited decreased serum thyroxine (T4) levels. Notably, since reproductive effects were used to support 2016 draft health advisories and immune effects were used in 2022 drinking water health advisories released by the United States Environmental Protection Agency for PFOS and perfluorooctanoic acid (PFOA), these novel data can potentially support advisories for PFHxS because relevant points of departure emerge at similar thresholds in a wild mammal and corroborate the general understanding of per- and polyfluoroalkyl substances (PFAS).

Structural and molecular changes in the rat myocardium following perfluoroctane sulfonate (PFOS) exposure are mitigated by quercetin via modulating HSP 70 and SERCA 2.

Perfluorooctane sulfonate (PFOS) is a man-made fluorinated compound employed in a variety of industrial and civilian applications. Due to its long elimination half-life and promotion of oxidative stress and inflammation, it is one of the most abundant organic contaminants. The present study was designed to determine the cytotoxic effect of PFOS on adult male rat cardiac tissue and to assess the cardioprotective role of the flavonoid quercetin (Que), which possesses antioxidant, anti-inflammatory, and anti-apoptotic properties. Twenty-four adult male Sprague-Dawley rats were randomly divided into four equal groups: Group I (Control). Group II (Que) received Que (75 mg/kg/day for 4 weeks) by oral gavage. Group III (PFOS group): supplemented orally with PFOS (20 mg/kg/day for 4 weeks) and Group IV (PF OS/Que). The rat heart was processed for histological, immunohistochemical, and gene expression studies. The PFOS group showed histological alterations in the myocardium that were partially reversed by the administration of Que. The inflammatory biomarkers (TNF, IL-6, and IL-1), lipid profile, TSH, MDA, and serum cardiac enzymes (LDH and CK-MB) were all altered. These findings collectively suggest that PFOS had adverse effects on the cardiac muscle structure, and these effects were alleviated by quercetin, which is a promising cardioprotective flavonoid.

Perfluorohexane sulfonate (PFHxS) disturbs the estrous cycle, ovulation rate, oocyte cell communication and calcium homeostasis in mice.

Perfluoroalkyl substances are man-made chemicals with ample consumer and industrial applications. They are widely used and are resistant to environmental and metabolic degradation. Several studies have evaluated the effects of Perfluorohexane sulfonate on reproduction. However, there are few reports exploring the cell and molecular mechanisms of its toxicity in the ovary. The aim of this study was to investigate the effects of PFHxS exposure on the estrous cycle, ovulation rate, and the underlying mechanisms of action in female mice in vivo. The animals received a single sub-lethal dose of PFHxS (25.1 mg/kg, 62.5 mg/kg) or vehicle and were stimulated to obtain immature cumulus cell-oocyte complexes (COCs) from the ovaries, or superovulated to develop mature COCs. To evaluate oocyte physiology, Gap-junction intercellular communication (GJIC) was analyzed in immature COCs and calcium homeostasis was evaluated in mature oocytes. PFHxS exposure prolonged the estrous cycle and decreased ovulation rate in female mice. Connexins, Cx43 and Cx37, were downregulated and GJIC was impaired in immature COCs, providing a possible mechanism for the alterations in the estrous cycle and ovulation. No morphological abnormalities were observed in the mature PFHxS-exposed oocytes, but calcium homeostasis was affected. This effect is probably due, at least partially, to deregulation of the endoplasmic reticulum calcium modulator, Stim1. These mechanisms of ovarian injury could explain the reported correlation among PFHxS levels and subfertility in women undergoing fertility treatments.

Di-anionic self-associating supramolecular amphiphiles (SSAs) as antimicrobial agents against MRSA and Escherichia coli.

Herein, we report a series of di-anionic supramolecular self-associating amphiphiles (SSAs). We elucidate the antimicrobial properties of these SSAs against both methicillin resistant Staphylococcus aureus and Escherichia coli. In addition, we show this class of compound to form both intra- and intermolecular hydrogen bonded macrocyclic structures in the solid state.

G2-S16 Polyanionic Carbosilane Dendrimer Can Reduce HIV-1 Reservoir Formation by Inhibiting Macrophage Cell to Cell Transmission.

Human immunodeficiency virus (HIV-1) is still a major problem, not only in developing countries but is also re-emerging in several developed countries, thus the development of new compounds able to inhibit the virus, either for prophylaxis or treatment, is still needed. Nanotechnology has provided the science community with several new tools for biomedical applications. G2-S16 is a polyanionic carbosilane dendrimer capable of inhibiting HIV-1 in vitro and in vivo by interacting directly with viral particles. One of the main barriers for HIV-1 eradication is the reservoirs created in primoinfection. These reservoirs, mainly in T cells, are untargetable by actual drugs or immune system. Thus, one approach is inhibiting HIV-1 from reaching these reservoir cells. In this context, macrophages play a main role as they can deliver viral particles to T cells establishing reservoirs. We showed that G2-S16 dendrimer is capable of inhibiting the infection from infected macrophages to healthy T CD4/CD8 lymphocytes by eliminating HIV-1 infectivity inside macrophages, so they are not able to carry infectious particles to other body locations, thus preventing the reservoirs from forming.

High Preventive Effect of G2-S16 Anionic Carbosilane Dendrimer against Sexually Transmitted HSV-2 Infection.

Anionic carbosilane dendrimers such as G2-S16 are very effective in preventing HSV-2 infection both in vitro and in vivo. We present the main achievements obtained for the G2-S16 dendrimer in vivo, especially related to its efficacy against HSV-2 infection. Moreover, we discuss the mechanisms by which the G2-S16 dendrimer applied vaginally as a topical microbicide has been demonstrated to be safe and harmless for the vaginal microbiome balance, as both conditions present an essential step that has to be overcome during microbicide development. This review points to the marked protective effect of the G2-S16 dendrimer against sexually transmitted HSV-2 infection, supporting its role as a possible microbicide against HSV-2 infection.

NPY1R-targeted peptide-mediated delivery of a dual PPARα/γ agonist to adipocytes enhances adipogenesis and prevents diabetes progression.

OBJECTIVE: PPARα/γ dual agonists have been in clinical development for the treatment of metabolic diseases including type 2 diabetes and dyslipidemia. However, severe adverse side effects led to complications in clinical trials. As most of the beneficial effects rely on the compound activity in adipocytes, the selective targeting of this cell type is a cutting-edge strategy to develop safe anti-diabetic drugs. The goal of this study was to strengthen the adipocyte-specific uptake of the PPARα/γ agonist tesaglitazar via NPY1R-mediated internalization. METHODS: NPY1R-preferring peptide tesaglitazar-[F7, P34]-NPY (tesa-NPY) was synthesized by a combination of automated SPPS and manual couplings. Following molecular and functional analyses for proof of concept, cell culture experiments were conducted to monitor the effects on adipogenesis. Mice treated with peptide drug conjugates or vehicle either by gavage or intraperitoneal injection were characterized phenotypically and metabolically. Histological analysis and transcriptional profiling of the adipose tissue were performed. RESULTS: In vitro studies revealed that the tesaglitazar-[F7, P34]-NPY conjugate selectively activates PPARγ in NPY1R-expressing cells and enhances adipocyte differentiation and adiponectin expression in adipocyte precursor cells. In vivo studies using db/db mice demonstrated that the anti-diabetic activity of the peptide conjugate is as efficient as that of systemically administered tesaglitazar. Additionally, tesa-NPY induces adipocyte differentiation in vivo. CONCLUSIONS: The use of the tesaglitazar-[F7, P34]-NPY conjugate is a promising strategy to apply the beneficial PPARα/γ effects in adipocytes while potentially omitting adverse effects in other tissues.

In vivo liposomal delivery of PPARα/γ dual agonist tesaglitazar in a model of obesity enriches macrophage targeting and limits liver and kidney drug effects.

Macrophages are important regulators of obesity-associated inflammation and PPARα and -γ agonism in macrophages has anti-inflammatory effects. In this study, we tested the efficacy with which liposomal delivery could target the PPARα/γ dual agonist tesaglitazar to macrophages while reducing drug action in common sites of drug toxicity: the liver and kidney, and whether tesaglitazar had anti-inflammatory effects in an in vivo model of obesity-associated dysmetabolism. Methods: Male leptin-deficient (ob/ob) mice were administered tesaglitazar or vehicle for one week in a standard oral formulation or encapsulated in liposomes. Following the end of treatment, circulating metabolic parameters were measured and pro-inflammatory adipose tissue macrophage populations were quantified by flow cytometry. Cellular uptake of liposomes in tissues was assessed using immunofluorescence and a broad panel of cell subset markers by flow cytometry. Finally, PPARα/γ gene target expression levels in the liver, kidney, and sorted macrophages were quantified to determine levels of drug targeting to and drug action in these tissues and cells. Results: Administration of a standard oral formulation of tesaglitazar effectively treated symptoms of obesity-associated dysmetabolism and reduced the number of pro-inflammatory adipose tissue macrophages. Macrophages are the major cell type that took up liposomes with many other immune and stromal cell types taking up liposomes to a lesser extent. Liposome delivery of tesaglitazar did not have effects on inflammatory macrophages nor did it improve metabolic parameters to the extent of a standard oral formulation. Liposomal delivery did, however, attenuate effects on liver weight and liver and kidney expression of PPARα and -γ gene targets compared to oral delivery. Conclusions: These findings reveal for the first time that tesaglitazar has anti-inflammatory effects on adipose tissue macrophage populations in vivo. These data also suggest that while nanoparticle delivery reduced off-target effects, yet the lack of tesaglitazar actions in non-targeted cells such (as hepatocytes and adipocytes) and the uptake of drug-loaded liposomes in many other cell types, albeit to a lesser extent, may have impacted overall therapeutic efficacy. This fulsome analysis of cellular uptake of tesaglitazar-loaded liposomes provides important lessons for future studies of liposome drug delivery.

Importance of thorough tissue and cellular level characterization of targeted drugs in the evaluation of pharmacodynamic effects.

Targeted nanoparticle delivery is a promising strategy for increasing efficacy and limiting side effects of therapeutics. When designing a targeted liposomal formulation, the in vivo biodistribution of the particles must be characterized to determine the value of the targeting approach. Peroxisome proliferator-activated receptor (PPAR) agonists effectively treat metabolic syndrome by decreasing dyslipidemia and insulin resistance but side effects have limited their use, making them a class of compounds that could benefit from targeted liposomal delivery. The adipose targeting sequence peptide (ATS) could fit this role, as it has been shown to bind to adipose tissue endothelium and induce weight loss when delivered conjugated to a pro-apoptotic peptide. To date, however, a full assessment of ATS in vivo biodistribution has not been reported, leaving important unanswered questions regarding the exact mechanisms whereby ATS targeting enhances therapeutic efficacy. We designed this study to evaluate the biodistribution of ATS-conjugated liposomes loaded with the PPARα/γ dual agonist tesaglitazar in leptin-deficient ob/ob mice. The ATS-liposome biodistribution in adipose tissue and other organs was examined at the cellular and tissue level using microscopy, flow cytometry, and fluorescent molecular tomography. Changes in metabolic parameters and gene expression were measured by target and off-target tissue responses to the treatment. Unexpectedly, ATS targeting did not increase liposomal uptake in adipose relative to other tissues, but did increase uptake in the kidneys. Targeting also did not significantly alter metabolic parameters. Analysis of the liposome cellular distribution in the stromal vascular fraction with flow cytometry revealed high uptake by multiple cell types. Our findings highlight the need for thorough study of in vivo biodistribution when evaluating a targeted therapy.

BHQ-Cyanine-Based "Off-On" Long-Circulating Assembly as a Ferroptosis Amplifier for Cancer Treatment: A Lipid-Peroxidation Burst Device.

Ferroptosis is an iron-dependent cell death caused by accumulation of lipid peroxidation (LPO), which is a new strategy for cancer treatment. Th current ferroptosis therapy nanodevices have low efficiency and side effects generally. Hence, we developed a Black Hole Quencher (BHQ)-based fluorescence "off-on" nanophotosensitizer complex assembly (CSO-BHQ-IR780-Hex/MIONPs/Sor). CSO-connected BHQ-IR780-Hex and -loaded magnetic iron oxide nanoparticles (MIONPs) and sorafenib (Sor) formed a very concise functionalized delivery system. CSO-BHQ-IR780-Hex disassembled by GSH attack and released IR780-Hex, MIONPs, and sorafenib. IR780-Hex anchored to the mitochondrial membrane, which would contribute to amplifying the efficiency of the photosensitizer. When NIR irradiation was given to CSO-BHQ-IR780-Hex/MIONPs/Sor-treated cells, iron supply increased, the xCT/GSH/GPX-4 system was triggered, and a lot of LPO burst. A malondialdehyde test showed that LPO in complex assembly-treated cells was explosive and increased about 18-fold compared to the control. The accumulation process of particles was monitored by an IR780-Hex photosensitizer, which showed an excellent tumor target ability by magnetic of nanodevice in vivo. Interestingly, the half-life of sorafenib in a nanodevice was increased about 26-fold compared to the control group. Importantly, the complex assembly effectively inhibits tumor growth in the breast tumor mouse model. This work would provide ideas in designing nanomedicines for the ferroptosis treatment of cancer.

Effects of chlorinated polyfluoroalkyl ether sulfonate in comparison with perfluoroalkyl acids on gene profiles and stemness in human mesenchymal stem cells.

Chlorinated polyfluoroalkyl ether sulfonate (Cl-PFESA) is a novel alternative of perfluorooctane sulfonate (PFOS). While its health risks remain unknown, there is preliminary evidence of developmental toxicity. In the present study, human bone mesenchymal stem cells (hBMSCs) were used to evaluate the effects of Cl-PFESA at non-cytotoxic concentrations on molecular regulation and cellular function of stem cells compared to PFOS, perfluorohexane sulfonate (PFHxS) and perfluorooctanoic acid (PFOA). Gene profiles of hBMSCs exposed to 100 nM of Cl-PFESA and the other 3 perfluoroalkyl acids (PFAAs) correlated significantly with each other. A total of 261 genes were found to be affected by all 4 compounds. Functional annotation analysis revealed that osteoblast differentiation, ERK1/2, TGFß and calcium signalling were interfered. Moreover, DUSP mRNA and P-SMAD protein, key factors in ERK and TGFß/SMAD signaling, were decreased by Cl-PFESA. Furthermore, intracellular calcium image suggested that calcium transients were enhanced by Cl-PFESA with lower effective concentrations and more prolonged induction than PFOS and PFHxS. Immunofluorescence staining confirmed that the stemness marker CD44 was dose-dependently repressed by Cl-PFESA. In the osteogenic differentiation following exposure to 100 nM of Cl-PFESA, both mRNA and protein of RUNX2, a target of multiple osteogenic pathways, was depressed on differentiation day 7. Exposure to Cl-PFESA at human relevant concentrations during a vulnerable period before differentiation posed persistent effects on hBMSCs, with common or even stronger potency compared to PFAAs.

Uptake and elimination of emerging polyfluoroalkyl substance F-53B in zebrafish larvae: Response of oxidative stress biomarkers.

6:2 chlorinated polyfluorinated ether sulfonate (F-53B) has been widely applied as a mist suppressant to replace perfluorooctane sulfonate (PFOS) in the metal plating industry in China for decades. Recently, F-53B has been frequently identified in the aquatic environment and wild-caught fish. However, studies on the uptake and elimination kinetics, and the toxicological effects of F-53B were very scarce. In this study, zebrafish larvae (72 h post fertilization, hpf) were exposed to F-53B (10, 100 µg/L) for 48 h, followed by a 24 h of depuration to examine both the dynamics of accumulation and elimination of F-53B and responses of antoxidant defense system in fish. The results showed that F-53B rapidly accumulated in zebrafish larvae in a concentration and time-dependent manner with BCF values of 3612-3615, but was eliminated slowly (half-life ranged from 241.5 to 258.6 h). F-53B exposure induced oxidative stress in zebrafish larvae, as reflected by the reduction in the GSH and MDA contents, CAT, SOD, CuZn-SOD, and GSH-ST activities, and the increase in GSH-Px activity as well as CAT and SOD protein levels. However, these oxidative stress markers were restored to control levels except for a decrease in protein level of SOD after depuration. Collectively, the results of this work indicate that F-53B behaves like PFOS and is bioaccumulative and persistent in zebrafish larvae, and further induced oxidative stress responses.

The Immunomodulatory Properties of Propyl-Propane Thiosulfonate Contribute to its Intestinal Anti-Inflammatory Effect in Experimental Colitis.

SCOPE: Propyl-propane thiosulfonate (PTSO) is a component isolated from garlic (Allium sativum) with antioxidant, anti-inflammatory, immunomodulatory, and antimicrobial properties. In consequence, PTSO can be a potential candidate for the treatment of inflammatory bowel diseases. METHODS AND RESULTS: The anti-inflammatory effects of PTSO are studied in two mice models of colitis: 2,4-dinitrobenzene sulfonic acid (DNBS) (PTSO doses: 0.01-10 mg kg-1 ) and dextran sodium sulfate (DSS) (PTSO doses: 0.01-0.1 mg kg-1 ). The immunomodulatory effects of PTSO (0.1-25 µm) are also shown in vitro in Caco-2 and THP-1 cells, reducing the production of pro-inflammatory mediators and downregulating mitogen-activated protein kinases (MAPKs) signaling pathways. This compound displays beneficial effects in both models of mouse colitis by reducing the expression of different pro-inflammatory mediators and improving the intestinal epithelial barrier integrity. Moreover, PTSO ameliorates the altered gut microbiota composition observed in DSS colitic mice. CONCLUSION: PTSO exerts intestinal anti-inflammatory activity in experimental colitis in mice. This anti-inflammatory activity can be associated with the immunomodulatory properties of PTSO through the regulation of the activity of cells involved in the inflammatory response. Furthermore, PTSO is able to restore the intestinal epithelial barrier function and to ameliorate the intestinal microbiota homeostasis, thus supporting its future development in human IBD.

Sulfonated Copolymers as Heparin-Mimicking Stabilizer of Fibroblast Growth Factor: Size, Architecture, and Monomer Distribution Effects.

Fibroblast growth factors (FGF) are involved in a wide range of biological processes such as cell proliferation and differentiation. In living organisms, the binding of FGF to its receptors are mediated through electrostatic interactions between FGF and naturally occurring heparin. Despite its prevalent use in medicine, heparin carries notable limitations; namely, its extraction from natural sources (expensive, low yield and extensive purification), viral contamination, and batch-to-batch heterogeneity. In this work a range of synthetic homopolymers and copolymers of sodium 2-acrylamido-2-methylpropanesulfonate were evaluated as potential FGF stabilizers. This was studied by measuring the proliferation of BaF3-FR1c cells, as a model assay, and the results will be compared with the natural stabilization and activation of FGF by heparin. This study explores the structure-activity relationship of these polysulfonated polymers with a focus on the effect of molecular weight, comonomer type, charge dispersion, and polymer architecture on protein stabilization.

Aminoethane Sulfonic Acid Magnesium Salt Inhibits Ca2+ Entry Through NMDA Receptor Ion Channel In Vitro.

The effect of a cerebroprotective agent magnesium bis-aminoethanesulfonate (laboratory code FS-LKhT-317) on intracellular calcium concentration was studied by the fluorescent imaging technique on neuroglial cell culture from Spraque-Dawley rat hippocampus. The substance produced a pronounced inhibitory effect and suppressed NMDA receptor activity in concentrations of ≥50 µM. The observed effects were reversible or partially reversible and were detected by a decrease in Ca2+ signal amplitude in neurons in response to NMDA applications in a Mg2+-free medium and by inhibition of Ca2+ pulses in magnesium-free medium (elimination of magnesium block).

G2-S16 dendrimer as a candidate for a microbicide to prevent HIV-1 infection in women.

Unprotected heterosexual intercourse is the first route for sustaining the global spread of human immunodeficiency virus type 1 (HIV-1), being responsible for 80% of new HIV-1 infections in the world. The presence of inflammation in the female reproductive tract and the presence of semen increases the risk of heterosexual HIV-1 transmission. This state-of-the-art research based on an innovative nanotechnology design was focused on a toxicological study of the limitation of the activity of the novel H2O-soluble anionic carbosilane dendrimer G2-S16 in the adult cervical and foreskin epithelia. The G2-S16 dendrimer did not cause any irritation or inflammation in the vaginal epithelium, proving that this dendrimer is a safe nanocompound for vaginal application to control viral transmission. It was shown that no significant differences were found in mortality, sublethal or teratogenic effects when the zebra fish embryos were treated with G2-S16. In short, G2-S16 seems to be an ideal candidate for the development of a topical microbicide against HIV-1 infection and the next step is try in clinical trials, because of its great in vivo biocompatibility, as well as its ability to halt HIV-1 infection in the presence of semen.

Spectral Unmixing Plate Reader: High-Throughput, High-Precision FRET Assays in Living Cells.

We have developed a microplate reader that records a complete high-quality fluorescence emission spectrum on a well-by-well basis under true high-throughput screening (HTS) conditions. The read time for an entire 384-well plate is less than 3 min. This instrument is particularly well suited for assays based on fluorescence resonance energy transfer (FRET). Intramolecular protein biosensors with genetically encoded green fluorescent protein (GFP) donor and red fluorescent protein (RFP) acceptor tags at positions sensitive to structural changes were stably expressed and studied in living HEK cells. Accurate quantitation of FRET was achieved by decomposing each observed spectrum into a linear combination of four component (basis) spectra (GFP emission, RFP emission, water Raman, and cell autofluorescence). Excitation and detection are both conducted from the top, allowing for thermoelectric control of the sample temperature from below. This spectral unmixing plate reader (SUPR) delivers an unprecedented combination of speed, precision, and accuracy for studying ensemble-averaged FRET in living cells. It complements our previously reported fluorescence lifetime plate reader, which offers the feature of resolving multiple FRET populations within the ensemble. The combination of these two direct waveform-recording technologies greatly enhances the precision and information content for HTS in drug discovery.