Evaluation of SV40-transformed synovial fibroblasts in the study of rheumatoid arthritis pathogenesis

Comparison of Stress and Suicide-Related Behaviors Among Korean Youths Before and During the COVID-19 Pandemic

IMPORTANCE

The COVID-19 pandemic has had a substantial psychological effect on young people. A quantitative assessment of the association between the pandemic and stress and suicidality in youths is needed.

OBJECTIVE

To investigate the association of the COVID-19 pandemic with self-reported stress and suicide-related behaviors in youths.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the the Korea Youth Risk Behavior Web-based Survey (KYRBWS) conducted in 2019 and 2020 with youths aged 12 to 18 years. Statistical analysis was performed from January to February 2021.

MAIN OUTCOMES AND MEASURES

The odds ratios (ORs) with 95% CIs for subjective stress level, sadness or despair, suicidal thoughts, suicide planning, and suicide attempts among 2020 participants were compared with those of the 2019 participants using multiple logistic regression analysis with complex sampling using weighted values.

RESULTS

The 48 443 youths in the 2019 KYRBWS (24 917 male youths [51.3%]; mean [SD] age, 15.0 [1.7] years) and the 44 216 youths in the 2020 KYRBWS (23 103 male youths [52.5%]; mean [SD] age, 15.1 [1.7] years) were compared. The degree of subjective stress was lower in the 2020 participants than in the 2019 participants (severe stress: adjusted OR [aOR], 0.90 [95% CI, 0.83-0.97]; very severe stress: aOR, 0.65 [95% CI, 0.60-0.72]). Sadness or despair was also lower in the 2020 participants than in the 2019 participants (aOR, 0.81 [95% CI, 0.78-0.84]). There were fewer suicide-related behaviors, including suicidal thoughts, suicide planning, and suicide attempts, among the 2020 participants than among the 2019 participants (suicidal thoughts: aOR, 0.77 [95% CI, 0.73-0.80]; suicide planning: aOR = 0.88 [95% CI, 0.81-0.96]; suicide attempts: aOR, 0.64 [95% CI, 0.58-0.70]).

CONCLUSIONS AND RELEVANCE

This cross-sectional study found that severe stress, sadness or despair and suicide-related behaviors had inverse associations with the early COVID-19 pandemic in Korean youths. These findings suggest that levels of high stress decreased among Korean youths in the early period of the pandemic compared with prepandemic levels.

Folate receptor-targeted mixed polysialic acid micelles for combating rheumatoid arthritis: in vitro and in vivo evaluation

OBJECTIVE

Rheumatoid arthritis (RA) is associated with chronic inflammation. The suppression of inflammation is key to the treatment of RA. Glucocorticoids (GCs) are classical anti-inflammatory drugs with several disadvantages such as poor water solubility and low specificity in the body. These disadvantages are the reasons for the quick elimination and side effects of GCs in vivo. Micelles are ideal carriers for GCs delivery to inflamed synovium. We set out to improve the targeting and pharmacokinetic profiles of GCs by preparing a targeting micelle system.

METHODS

In this study, natural chlosterol (CC) and folic acid (FA) were used to fabricate polysialic acid (PSA) micelles for the targeted delivery of Dexamethasone (Dex). The biodistribution and therapeutic efficacy of the resulting micelles were evaluated in vitro and in vivo.

RESULTS

PSA-CC and FA-PSA-CC micelles showed a size below 100 nm and a moderate negative charge. PSA-CC and FA-PSA-CC micelles could also enhance the intracellular uptake of Dex and the suppression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in vitro and in vivo. Arthritis mice showed reduced paw thickness and clinical arthritis index using PSA-CC and FA-PSA-CC micelle treatment. Micellized Dex demonstrated a 4 ∼ 5 fold longer elimination half-life and a 2 ∼ 3 folds higher bioavailability than commercial Dex injection. FA modification significantly improved the anti-inflammatory efficacy of PSA-CC micelles.

CONCLUSION

FA-PSA-CC micelles demonstrated significant advantages in terms of the suppression of inflammation and the treatment of inflammatory arthritis. These reliable and stable micelles possess a high potential to be transferred for clinical use.

A comparison of strategies for immortalizing mouse embryonic fibroblasts

The genetically amenable mouse model has led to a large collection of genetically defined lines from which mouse embryonic fibroblasts (MEFs) have been derived. Despite their widespread use, MEFs are time consuming to generate and have a limited lifespan. Immortalizing primary MEFs with the desired genetic manipulations greatly reduces culture maintenance time, enables the generation of near limitless amounts of protein lysate, and facilitates biological replicates during experimentation. In this work, we have evaluated several approaches for MEF immortalization. When cultivated at 3% O₂, some primary MEF lines could be proliferated for > 40 passages with a median doubling rate of 45 ± 55 h (n = 8). However, serial passaging at 3% O₂ achieved spontaneous immortalization with varying success. If cultures seemed to be reaching their Hayflick limit when cultivated at 3% O₂, supplementing the culture media with 5 µM ROCK inhibitor Y-27632 helped to extend proliferation and achieve spontaneous immortalization. MEFs immortalized via SV40 Ta infection reliably produced cell lines with a median doubling rate of 25 ± 9 h (n = 9) and viability greater than 90%. In addition to a discussion of the characteristics of cell lines generated with various immortalization strategies, pros and cons of each strategy are included as are recommendations for generating immortalized MEFs.

Investigation of the cytokine response to NF-κB decoy oligonucleotide coated polysaccharide based nanoparticles in rheumatoid arthritis in vitro models

Introduction

The transcription factor nuclear factor-kappa B (NF-κB) is highly involved in regulation of a number of cellular processes, including production of inflammatory mediators. Thus, this transcription factor plays a role in pathology of many diseases, including rheumatoid arthritis, an autoimmune disease hallmarked by an imbalance of pro and anti-inflammatory cytokines. Small nucleic acids with sequences that mimic the native binding site of NF-κB have been proposed as treatment options for RA; however due to low cellular penetration and a high degree of instability, clinical applications of these therapeutics have been limited.

Methods

Here, we describe the use of N-trimethyl chitosan-polysialic acid (PSA-TMC) nanoparticles coated with decoy oligodeoxynucleotides (ODNs) specific to transcription factor NF-κB (PSA-TMC-ODN) as a method to enhance the stability of the nucleic acids and facilitate increased cellular penetration. In addition to decoy ODN, PSA-TMC nanoparticles were loaded with RA therapeutic methotrexate (MTX), to assess the anti-inflammatory efficacy of a combination therapy approach. Two different in vitro models, a cell line based model as well as a primary RA cell model were used to investigate anti-inflammatory activity. One way ANOVA followed by Holm-Sidak stepdown comparisons was used to determine statistical significance.

Results

In general, free ODN did not significantly affect secretion of pro-inflammatory cytokines interleukin-6 (IL-6) and interleukin-8, (IL-8) while free MTX had variable efficacy. However, PSA-TMC-ODN and PSA-TMC-ODN-MTX resulted in significant decreases in the inflammatory mediators IL-6 and IL-8 in both cell models. In addition, PSA-TMC exhibited sufficient cellular uptake, as observed through fluorescence microscopy.

Conclusions

These results support our previous findings that PSA-TMC nanoparticles are an effective delivery vehicle for small nucleic acids, and effectively alter the pro-inflammatory state characteristic of RA.