Multiomic single-cell sequencing defines tissue-specific responses in Stevens-Johnson Syndrome and Toxic epidermal necrolysis.

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) is a rare but life-threatening cutaneous drug reaction mediated by human leukocyte antigen (HLA) class I-restricted CD8+ T-cells. To obtain an unbiased assessment of SJS/TEN cellular immunopathogenesis, we performed single-cell (sc) transcriptome, surface proteome, and TCR sequencing on unaffected skin, affected skin, and blister fluid from 17 SJS/TEN patients. From 119,784 total cells, we identified 16 scRNA-defined subsets, confirmed by subset-defining surface protein expression. Keratinocytes upregulated HLA and IFN-response genes in the affected skin. Cytotoxic CD8+ T-cell subpopulations of expanded and unexpanded TCRαß clonotypes were shared in affected skin and blister fluid but absent or unexpanded in SJS/TEN unaffected skin. SJS/TEN blister fluid is a rich reservoir of oligoclonal CD8+ T-cells with an effector phenotype driving SJS/TEN pathogenesis. This multiomic database will act as the basis to define antigen-reactivity, HLA restriction, and signatures of drug-antigen-reactive T-cell clonotypes at a tissue level.

Updates on the immunopathology and genomics of severe cutaneous adverse drug reactions.

Severe cutaneous adverse reactions (SCARs) such as Stevens-Johnson syndrome, toxic epidermal necrolysis (SJS/TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS)/drug-induced hypersensitivity syndrome (DIHS) cause significant morbidity and mortality and impede new drug development. HLA class I associations with SJS/TEN and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome have aided preventive efforts and provided insights into immunopathogenesis. In SJS/TEN, HLA class I-restricted oligoclonal CD8+ T-cell responses occur at the tissue level. However, specific HLA risk allele(s) and antigens driving this response have not been identified for most drugs. HLA risk alleles also have incomplete positive and negative predictive values, making truly comprehensive screening currently challenging. Although, there have been key paradigm shifts in knowledge regarding drug hypersensitivity, there are still many open and unanswered questions about SCAR immunopathogenesis, as well as genetic and environmental risk. In addition to understanding the cellular and molecular basis of SCAR at the single-cell level, identification of the MHC-restricted drug-reactive self- or viral peptides driving the hypersensitivity reaction will also be critical to advancing premarketing strategies to predict risk at an individual and drug level. This will also enable identification of biologic markers for earlier diagnosis and accurate prognosis, as well as drug causality and targeted therapeutics.

Transcriptome Profile Alteration with Cadmium Selenide/Zinc Sulfide Quantum Dots in Saccharomyces cerevisiae.

Quantum Dots (QDs) are becoming more prevalent in products used in our daily lives, such as TVs and laptops, due to their unique and tunable optical properties. The possibility of using QDs as fluorescent probes in applications, such as medical imaging, has been a topic of interest for some time, but their potential toxicity and long-term effects on the environment are not well understood. In the present study, we investigated the effects of yellow CdSe/ZnS-QDs on Saccharomyces cerevisiae. We utilized growth assays, RNA-seq, reactive oxygen species (ROS) detection assays, and cell wall stability experiments to investigate the potential toxic effects of CdSe/ZnS-QDs. We found CdSe/ZnS-QDs had no negative effects on cell viability; however, cell wall-compromised cells showed more sensitivity in the presence of 10 µg/mL CdSe/ZnS-QDs compared to non-treated cells. In CdSe/ZnS-treated and non-treated cells, no significant change in superoxide was detected, but according to our transcriptomic analysis, thousands of genes in CdSe/ZnS-treated cells became differentially expressed. Four significantly differentiated genes found, including FAF1, SDA1, DAN1, and TIR1, were validated by consistent results with RT-qPCR assays. Our transcriptome analysis led us to conclude that exposure of CdSe/ZnS-QDs on yeast significantly affected genes implicated in multiple cellular processes.

Transcriptome profile with 20 nm silver nanoparticles in yeast.

Engineered nanomaterials are commercially used in everyday products including zinc sunscreens and water-resistant fabrics and surfaces. Therefore, understanding the effects of engineered nanomaterials on the environment is crucial for the responsible use of these technologies. We investigated the effects of 20 nm spherical citrate-coated silver nanoparticles (AgNPs) on the budding yeast Saccharomyces cerevisiae. Our growth assay showed that AgNPs have an inhibitory effect on yeast growth with concentrations above 5 µg/mL. Hundreds of genes in AgNP-treated cells were differentially expressed according to our transcriptome analysis based on RNAseq, including genes implicated in rRNA processing, ribosome biogenesis, cell wall formation, cell membrane integrity and mitochondrial functions. In particular, genes whose functions are associated with processing of small and large subunits of ribosomes were upregulated, while genes for cell wall/plasma membrane/mitochondrial integrity were downregulated. Consistently, our cell wall stability assay confirmed that cells with AgNPs are more susceptible to cell wall damage than non-treated cells. Levels of four significantly altered genes with AgNPs, including FAF1, SDA1, TIR1 and DAN1, were validated by reproducible results with RT-qPCR assays. Our transcriptome profile leads us to conclude that the exposure of cells to sublethal amounts of AgNPs affects many cellular processes negatively.

Effectiveness of earmuffs in protecting hearing during shooting practice: a case-study.

OBJECTIVE: This investigation was designed to determine the effectiveness of earmuffs worn by a single individual during shooting practice. DESIGN: Single subject experimental design. STUDY SAMPLE: A 21-year old female recreational shooter, who practiced shooting on a regular basis while using earmuffs participated in the study. She reported occasional noise exposures of other types including car races and demolition derbies but no hearing difficulties or symptoms such as tinnitus. Her auditory sensitivity was within normal limits. On each test-day, distortion product otoacoustic emissions (DPOAEs) were recorded in a sound-attenuated booth before and after a shooting practice session conducted while using earmuffs. Data were collected across six different days, across six weeks, to allow recovery from each of the six shooting practice sessions. The participant was requested to refrain from other noisy activities in between sessions. RESULTS: Significant changes in DPOAE signal-to-noise ratios (SNRs) were apparent following the shooting sessions, at 1184 and 4761 Hz in the left ear suggesting that the hearing protection worn by the individual was insufficient to completely protect her hearing. CONCLUSIONS: It is possible to assess the effectiveness of hearing protection worn by individual shooters using repeated measurements of DPOAEs embedded in a single case-research design.