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Human voltage-gated sodium (hNaV) channels are responsible for initiating and propagating action potentials in excitable cells and mutations have been associated with numerous cardiac and neurological disorders. hNaV1.7 channels are expressed in peripheral neurons and are promising targets for pain therapy. The tarantula protoxin-2 (PTx2) has high selectivity for hNaV1.7 and serves as a valuable scaffold to design novel therapeutics to treat pain. Here, we used computational modeling methods to study the molecular mechanisms by which PTx2 exhibits state-dependent binding to hNaV1.7 voltage-sensing domains (VSDs). Using Rosetta structural modeling methods, we constructed atomistic structural models of the hNaV1.7 VSD II and IV in the activated and deactivated states with docked PTx2. We then performed microsecond-long all-atom molecular dynamics (MD) simulations of the systems in hydrated lipid bilayers. Our simulations revealed that PTx2 binds most favorably to VSD II and IV in the deactivated conformations. These state-specific interactions are mediated primarily by PTx2 R22, K26, and K27 residues with the VSD S3-S4 loop, and L23, W24 with the S1-S2 loop. The surrounding membrane lipids facilitated the binding process. Our work revealed important protein-protein contacts that contribute to high-affinity state-dependent toxin interaction with the channel. The workflow presented will prove useful for designing novel peptides with improved selectivity and potency for more effective and safe treatment of pain.SummaryVoltage-gated sodium channel NaV1.7 plays a major role in pain perception and is selectively inhibited by tarantula venom protoxin-2, used to design pain therapeutics. Here, Ngoet alapplied computational modeling to assess state-dependent protoxin-2 - NaV1.7 binding.

Achiral and chiral isomers of dipyrenoheteroles were synthesized via alkyne benzannulation. The electronic properties of these compounds were examined using cyclic voltammetry and differential pulse voltammetry. The enantiomers of the chiral isomers were separated, and their optical properties were examined in circular dichroism and circularly polarized luminescence studies. The chiral isomers exhibited a large bathochromic shift, relative to the achiral isomer, in both absorbance and fluorescence, resulting from decreased symmetry, rather than a change in the size of the backbone.

Osteoarthritis (OA), a progressive degenerative disease of cartilage in joints, is the most common cause of chronic disability in older adults. While OA is mostly considered an age-related pathology, women have a 1.5-fold higher risk of developing OA relative to men and experience more severe symptoms. Yet, they remain underrepresented in musculoskeletal research and clinical trials. Responsible for cartilage formation, articular chondrocytes experience physiological changes in OA, but the functional implications of such alterations remain largely unexplored due to difficulties in acquiring the data experimentally. Through reparameterization, we expand a mathematical chondrocyte model to investigate sex-specific OA pathogenesis. We performed sensitivity analysis to address the impact of ion channel activity in healthy and OA chondrocyte populations. Simulations show that in healthy female chondrocytes, the resting membrane potential is more depolarized than in healthy male chondrocytes, suggesting potential sex-specific emergent physiological differences in articular chondrocytes. In both sexes, the resting membrane potential of healthy chondrocytes is most sensitive to 𝐼𝐶𝑎−𝐴𝑇𝑃, 𝐼𝑁𝑎−𝑏, 𝐼𝑁𝑎𝐾 and 𝐼𝐾−𝑏, but in OA it depolarizes and becomes sensitive to 𝐼𝐾𝐷𝑅, 𝐼𝑁𝑎𝐾 and 𝐼𝐾−𝑏. Developed and evaluated against experimental data, our articular chondrocyte OA electrophysiological model can be used to further study OA pathology and sex-specific pathological OA changes.

Microprocessor (MP) is a complex involved in initiating the biogenesis of microRNAs (miRNAs) by cleaving primary microRNAs (pri-miRNAs). miRNAs are small single-stranded RNAs that play a key role in the post-transcriptional regulation of gene expression. Thus, understanding the molecular mechanism of MP is critical for interpreting the roles of miRNAs in normal cellular processes and during the onset of various diseases. MP comprises a ribonuclease enzyme, DROSHA, and a dimeric RNA-binding protein, which is called DGCR8 in humans and Pasha in Caenorhabditis elegans. DROSHA cleaves stem-loop structures located within pri-miRNAs to generate pre-miRNAs. Although the molecular mechanism of human MP (hMP; hDROSHA-DGCR8) is well understood, that of Caenorhabditis elegans MP (cMP; cDrosha-Pasha) is still largely unknown. Here, we reveal the molecular mechanism of cMP and show that it is distinct from that of hMP. We demonstrate that cDrosha and Pasha measure ∼16 and ∼25 bp along a pri-miRNA stem, respectively, and they work together to determine the site of cMP cleavage in pri-miRNAs. We also demonstrate the molecular basis for their substrate measurement. Thus, our findings reveal a previously unknown molecular mechanism of cMP; demonstrate the differences between the mechanisms of hMP and cMP; and provide a foundation for revealing the mechanisms regulating miRNA expression in different animal species.The Microprocessor complex that initiates miRNA biogenesis was discovered in animals in 2004. However, the molecular mechanism of C. elegans Microprocessor (cMP) has remained elusive since its discovery 18 years ago. In this study, we revealed the unique molecular mechanism of cMP by conducting high-throughput pri-miRNA cleavage assays. We demonstrated that cMP, consisting of cDrosha and Pasha, each can measure the stem lengths of pri-miRNAs. cDrosha measures ∼16 bp of the lower stem length, whereas Pasha measures ∼25 bp of the upper stem in pri-miRNAs. In addition, we identified the cleavage sites and cleavage efficiency of cMP in C. elegans pri-miRNAs. These results will be helpful for future studies of miRNA biogenesis in C. elegans.

In this study, extracts of shallot skin, flesh and whole bulbs were evaluated their inhibitory effect on xanthine oxidase activity in vitro. The results showed that the effect of shallot skin extract was superior to the extracts from flesh and whole bulb. The extraction of flavonoid from shallot skin was comprehensively investigate using one-factor-at-a-time and response surface methodology based on multivariable linear regression and artificial neural network. Four established models accurately illustrated the quantitative relationship between temperature, time of extraction, solvent and total flavonoids content, yield of extraction. The optimal conditions were determined as: temperature of 85 °C, time of 120 min and ethanol concentration of 50%. The IC50 values on xanthine oxidase of the extracts in optimal and sub-optimal conditions were 3.23 and 21.09 µg/mL while the total flavonoids contents were 20.26% and 13.89%, respectively. The docking results suggested that isorhamnetin-3-glucoside and other flavonoids in shallot skin might play a key role in xanthine oxidase activity of shallot extract.

Celery seed is a potential medicinal material for the development of anti-gout agents because of its uric acid-lowering, xanthine oxidase inhibitory, anti-inflammatory and analgesic effects. In this study, the process of extraction of flavonoid from celery seed was optimized using response surface methodology. Various algorithms were used in order to model the relationship between output response (yield of extraction, total flavonoid content) and input parameters (ethanol concentration, temperature and solvent/solid ratio). The best model was established using multiple linear regression (MLR) algorithm. The optimal conditions were determined as follows: ethanol concentration: 90%; temperature: 90°C and the solvent/solid ratio: 4 ml/g. At these conditions, the yield of extraction was 11.57 ± 1.46% and the total flavonoid content was 4.922 ± 0.312 mg/g. The xanthine oxidase inhibitory effect of apigenin - the main flavonoid of celery seed, was evaluated with the IC50 value of 0.247 µg/ml (95% CI 0.129–0.617 µg/ml). It was suggested that flavonoid might play a key role in the xanthine oxidase inhibitory activity of celery seed extract.

Moisturizers play an essential role in maintaining the integrity of the skin barrier by increasing stratum corneum hydration (SCH) and reducing transepidermal water loss (TEWL). According to dermatology and allergy guidelines, moisturizers should be applied on the skin within 3 min after bathing or showering. However, there is very little evidence supporting this recommendation. This study aimed to investigate the effectiveness of immediate and delayed moisturizing after bathing/washing on the improvement of SCH and TEWL.This was a crossover study of 60 healthy Vietnamese volunteers aged 18-25 years. In each subject, SCH and TEWL levels were measured at three areas: non-moisturized, immediate moisturizing after washing, and delayed moisturizing at 30 min after washing.In non-moisturized skin, SCH and TEWL levels were significantly different from the baseline at 60 min after washing, while significantly decreased TEWL levels were observed immediately after moisturizing. In addition, moisturized skin had significantly higher SCH and lower TEWL levels compared with non-moisturized areas at every time point (p 0.05). Interestingly, the percentage changes of SCH and TEWL levels from baseline did not differ between immediately and delayed moisturized areas.Tested moisturizer helped increase SCH and decrease TEWL; however, there was no difference in moisturizing effectiveness between immediate and delayed moisturizing in healthy skin. The recommendation of immediate application of moisturizers after bathing/washing should be reconsidered, and more studies are needed to establish a stronger recommendation.