Aminocatalytic Strategy for the Synthesis of Optically Active Benzothiophene Derivatives

A novel approach for the stereoselective synthesis of benzothiophene derivatives with a fused dihydropyran moiety is demonstrated. The reaction of 2‐alkylidenebenzothiophene‐3(2H)‐ones with dienamines derived from α,β‐unsaturated aldehydes and chiral secondary amines proceeds according to the inverse‐electron‐demand hetero‐Diels–Alder pathway. The formation of the aromatic benzothiophene moiety is a driving force for the developed reaction cascade. Target products bearing three adjacent stereogenic centers are obtained in excellent yields and in a highly stereoselective manner.

     

Vascularization Strategies in 3D Cell Culture Models: From Scaffold-Free Models to 3D Bioprinting

The discrepancies between the findings in preclinical studies, and in vivo testing and clinical trials have resulted in the gradual decline in drug approval rates over the past decades. Conventional in vitro drug screening platforms employ two-dimensional (2D) cell culture models, which demonstrate inaccurate drug responses by failing to capture the three-dimensional (3D) tissue microenvironment in vivo. Recent advancements in the field of tissue engineering have made possible the creation of 3D cell culture systems that can accurately recapitulate the cell–cell and cell–extracellular matrix interactions, as well as replicate the intricate microarchitectures observed in native tissues. However, the lack of a perfusion system in 3D cell cultures hinders the establishment of the models as potential drug screening platforms. Over the years, multiple techniques have successfully demonstrated vascularization in 3D cell cultures, simulating in vivo-like drug interactions, proposing the use of 3D systems as drug screening platforms to eliminate the deviations between preclinical and in vivo testing. In this review, the basic principles of 3D cell culture systems are briefly introduced, and current research demonstrating the development of vascularization in 3D cell cultures is discussed, with a particular focus on the potential of these models as the future of drug screening platforms.     

Boron Clusters as Enhancers of RNase H Activity in the Smart Strategy of Gene Silencing by Antisense Oligonucleotides

Boron cluster-conjugated antisense oligonucleotides (B-ASOs) have already been developed as therapeutic agents with “two faces”, namely as potential antisense inhibitors of gene expression and as boron carriers for boron neutron capture therapy (BNCT). The previously observed high antisense activity of some B-ASOs targeting the epidermal growth factor receptor (EGFR) could not be rationally assigned to the positioning of the boron cluster unit: 1,2-dicarba-closo-dodecaborane (0), [(3,3′-Iron-1,2,1′,2′-dicarbollide) (1-), FESAN], and dodecaborate (2-) in the ASO chain and its structure or charge. For further understanding of this observation, we performed systematic studies on the efficiency of RNase H against a series of B-ASOs models. The results of kinetic analysis showed that pyrimidine-enriched B-ASO oligomers activated RNase H more efficiently than non-modified ASO. The presence of a single FESAN unit at a specific position of the B-ASO increased the kinetics of enzymatic hydrolysis of complementary RNA more than 30-fold compared with unmodified duplex ASO/RNA. Moreover, the rate of RNA hydrolysis enhanced with the increase in the negative charge of the boron cluster in the B-ASO chain. In conclusion, a “smart” strategy using ASOs conjugated with boron clusters is a milestone for the development of more efficient antisense therapeutic nucleic acids as inhibitors of gene expression.     

ERAP/HLA-C and KIR Genetic Profile in Couples with Recurrent Implantation Failure

Proper embryo implantation depends on the tolerance of the maternal immune system to the fetus and its foreign paternal antigens. During implantation and early pregnancy, the dominant leukocytes in the uterus are uterine NK cells, expressing killer immunoglobulin-like receptors (KIR). KIRs recognize human leukocyte antigens (HLA-C) on the human trophoblast inherited from the father and mother. The antigenic peptides presented by the HLA are formed via their cleavage by endoplasmic reticulum aminopeptidases ERAP1 and ERAP2. The aim of this study was to assess the association of combined KIR genes and their HLA-C ligands, as well as ERAP1 and ERAP2 polymorphisms with recurrent implantation failure after in vitro fertilization (RIF). We tested 491 couples who underwent in vitro fertilization (IVF) and 322 fertile couples. Genotype CC rs27044 ERAP1 in female with a male’s HLA-C1C1 or HLA-C1C2 protected from RIF (p/p_corr. = 0.005/0.044, OR = 0.343; p/p_corr. = 0.003/0.027, OR = 0.442, respectively). Genotype TT rs30187 ERAP1 in female with a male’s HLA-C1C2 genotype increased the risk of RIF. Summarizing, in the combination of female ERAP1 and an HLA-C partner, the rs30187 C>T and rs27044 C>G polymorphisms play an important role in implantation failure.     

The Size-Dependent Effects of Silver Nanoparticles on Germination,Early Seedling Development and Polar Metabolite Profile of Wheat (Triticum aestivum L.)

The phytotoxicity of silver nanoparticles (Ag NPs) to plant seeds germination and seedlings development depends on nanoparticles properties and concentration, as well as plant species and stress tolerance degrees. In the present study, the effect of citrate-stabilized spherical Ag NPs (20 mg/L) in sizes of 10, 20, 40, 60, and 100 nm, on wheat grain germination, early seedlings development, and polar metabolite profile in 3-day-old seedlings were analyzed. Ag NPs, regardless of their sizes, did not affect the germination of wheat grains. However, the smaller nanoparticles (10 and 20 nm in size) decreased the growth of seedling roots. Although the concentrations of total polar metabolites in roots, coleoptile, and endosperm of seedlings were not affected by Ag NPs, significant re-arrangements of carbohydrates profiles in seedlings were noted. In roots and coleoptile of 3-day-old seedlings, the concentration of sucrose increased, which was accompanied by a decrease in glucose and fructose. The concentrations of most other polar metabolites (amino acids, organic acids, and phosphate) were not affected by Ag NPs. Thus, an unknown signal is released by small-sized Ag NPs that triggers affection of sugars metabolism and/or distribution.     

Chronic Ulcerative Stomatitis (CUS) as an Interdisciplinary Diagnostic Challenge: A Literature Review

Chronic ulcerative stomatitis (CUS) is a rarely reported disease affecting the oral cavity, most often affecting middle-aged Caucasian females. The aim of the present study is to present the diagnosis, differentiation, and interdisciplinary treatment of this rare disease. CUS is characterized by the presence of an oral erosive or ulcerative lesion. The autoimmune pathogenesis of CUS includes affecting the antigen’s activity by DNA-breaking and protein-hydrolyzing enzymes. The stratified epithelium-specific antinuclear antibodies (SES-ANA) are associated with CUS development. Clinically, the lesions presented in oral mucosa might resemble an erosive form of oral lichen planus, whereas gingival lesions seem to be similar to desquamative gingivitis related to dermatological diseases manifested in the oral cavity. Patients often report subjective symptoms related to oral mucosa and general symptoms. Histopathological presentation of CUS is often non-specific and includes sub-epithelial separation from underlying connective tissue, atrophic epithelium, and inflammatory infiltrate with an increased number of plasma cells and lymphocytes. Direct immunofluorescence (DIF) might be used in CUS diagnostics. CUS generally remains nonsusceptible to corticosteroid treatments; however, antimalarial drugs and calcineurin inhibitors are more effective. Further research should be conducted in order to implement a diagnostic protocol and observe the long-term results of CUS management.     

Development and Comprehensive Characteristics of Thermosensitive Liquid Suppositories of Metoprolol Based on Poly(lactide-co-glycolide) Nanoparticles

Thermosensitive liquid suppositories (LSs) carrying the model antihypertensive drug metoprolol tartrate (MT) were developed and evaluated. The fundamental purpose of this work was to produce, for the first time, liquid MT suppositories based on biodegradable nanoparticles and optimize their rheological and mechanical properties for prospective rectal administration. The nanoparticle system was based on a biodegradable copolymer synthesized by ring opening polymerization (ROP) of glycolide (GL) and L,L-lactide (LLA). Biodegradable nanoparticles loaded with the model drug were produced by the o/o method at the first stage of the investigation. Depending on the concentration of the drug in the sample, from 66 to 91% of MT was released over 12 h, according to first-order kinetics. Then, thermosensitive LSs with MT-loaded biodegradable nanoparticles were obtained by a cold method and their mechanical and rheological properties were evaluated. To adjust the thermogelling and mucoadhesive properties for rectal administration, the amounts of major formulation components such as poloxamers (P407, P188), Tween 80, hydroxypropylcellulose (HPC), polyvinylpyrrolidone (PVP), and sodium alginate were optimized. The in vitro release results revealed that more than 80% of the MT was released after 12 h, following also first-order kinetics. It was discovered that the diffusion process was dominant. The drug release profile was mainly governed by the rheological and mechanical properties of the developed formulation. Such a novel, thermosensitive formulation might be an effective alternative to hypertension treatment, particularly for unconscious patients, patients with mental illnesses, geriatric patients, and children.     

Oligomerization of Human Cystatin C—An Amyloidogenic Protein: An Analysis of Small Oligomeric Subspecies

Human cystatin C (HCC), an amyloidogenic protein, forms dimers and higher oligomers (trimers, tetramers and donut like large oligomers) via a domain-swapping mechanism. The aim of this study was the characterization of the HCC oligomeric states observed within the pH range from 2.2 to 10.0 and also in conditions promoting oligomerization. The HCC oligomeric forms obtained in different conditions were characterized using size exclusion chromatography, dynamic light scattering and small-angle X-ray scattering. The marked ability of HCC to form tetramers at low pH (2.3 or 3.0) and dimers at pH 4.0–5.0 was observed. HCC remains monomeric at pH levels above 6.0. Based on the SAXS data, the structure of the HCC tetramer was proposed. Changes in the environment (from acid to neutral) induced a breakdown of the HCC tetramers to dimers. The tetrameric forms of human cystatin C are formed by the association of the dimers without a domain-swapping mechanism. These observations were confirmed by their dissociation to dimers at pH 7.4.     

Preliminary Evidence of the Potent and Selective Adenosine A2B Receptor Antagonist PSB-603 in Reducing Obesity and Some of Its Associated Metabolic Disorders in Mice

The adenosine A_2A and A_2B receptors are promising therapeutic targets in the treatment of obesity and diabetes since the agonists and antagonists of these receptors have the potential to positively affect metabolic disorders. The present study investigated the link between body weight reduction, glucose homeostasis, and anti-inflammatory activity induced by a highly potent and specific adenosine A_2B receptor antagonist, compound PSB-603. Mice were fed a high-fat diet for 14 weeks, and after 12 weeks, they were treated for 14 days intraperitoneally with the test compound. The A₁/A_2A/A_2B receptor antagonist theophylline was used as a reference. Following two weeks of treatment, different biochemical parameters were determined, including total cholesterol, triglycerides, glucose, TNF-α, and IL-6 blood levels, as well as glucose and insulin tolerance. To avoid false positive results, mouse locomotor and spontaneous activities were assessed. Both theophylline and PSB-603 significantly reduced body weight in obese mice. Both compounds had no effects on glucose levels in the obese state; however, PSB-603, contrary to theophylline, significantly reduced triglycerides and total cholesterol blood levels. Thus, our observations showed that selective A_2B adenosine receptor blockade has a more favourable effect on the lipid profile than nonselective inhibition.