High throughput single cell long-read sequencing analyses of same-cell genotypes and phenotypes in human tumors.

Single-cell nanopore sequencing of full-length mRNAs transforms single-cell multi-omics studies. However, challenges include high sequencing errors and dependence on short-reads and/or barcode whitelists. To address these, we develop scNanoGPS to calculate same-cell genotypes (mutations) and phenotypes (gene/isoform expressions) without short-read nor whitelist guidance. We apply scNanoGPS onto 23,587 long-read transcriptomes from 4 tumors and 2 cell-lines. Standalone, scNanoGPS deconvolutes error-prone long-reads into single-cells and single-molecules, and simultaneously accesses both phenotypes and genotypes of individual cells. Our analyses reveal that tumor and stroma/immune cells express distinct combination of isoforms (DCIs). In a kidney tumor, we identify 924 DCI genes involved in cell-type-specific functions such as PDE10A in tumor cells and CCL3 in lymphocytes. Transcriptome-wide mutation analyses identify many cell-type-specific mutations including VEGFA mutations in tumor cells and HLA-A mutations in immune cells, highlighting the critical roles of different mutant populations in tumors. Together, scNanoGPS facilitates applications of single-cell long-read sequencing technologies.

Anaplastic transformation in thyroid cancer revealed by single-cell transcriptomics.

The deadliest anaplastic thyroid cancer (ATC) often transforms from indolent differentiated thyroid cancer (DTC); however, the complex intratumor transformation process is poorly understood. We investigated an anaplastic transformation model by dissecting both cell lineage and cell fate transitions using single-cell transcriptomic and genetic alteration data from patients with different subtypes of thyroid cancer. The resulting spectrum of ATC transformation included stress-responsive DTC cells, inflammatory ATC cells (iATCs), and mitotic-defective ATC cells and extended all the way to mesenchymal ATC cells (mATCs). Furthermore, our analysis identified 2 important milestones: (a) a diploid stage, in which iATC cells were diploids with inflammatory phenotypes and (b) an aneuploid stage, in which mATCs gained aneuploid genomes and mesenchymal phenotypes, producing excessive amounts of collagen and collagen-interacting receptors. In parallel, cancer-associated fibroblasts showed strong interactions among mesenchymal cell types, macrophages shifted from M1 to M2 states, and T cells reprogrammed from cytotoxic to exhausted states, highlighting new therapeutic opportunities for the treatment of ATC.

Long noncoding RNAs are substrates for cytoplasmic capping enzyme.

Cytoplasmic capping returns a cap to specific mRNAs, thus protecting uncapped RNAs from decay. Prior to the identification of cytoplasmic capping, uncapped mRNAs were thought to be degraded. Here, we test whether long noncoding RNAs (lncRNAs) are substrates of the cytoplasmic capping enzyme (cCE). The subcellular localisation of 14 lncRNAs associated with sarcomas were examined in U2OS osteosarcoma cells. We used 5' rapid amplification of cDNA ends (RACE) to assay uncapped forms of these lncRNAs. Inhibiting cytoplasmic capping elevated uncapped forms of selected lncRNAs indicating a plausible role of cCE in targeting them. Analysis of published cap analysis of gene expression (CAGE) data shows increased prevalence of certain 5'-RACE cloned sequences, suggesting that these uncapped lncRNAs are targets of cytoplasmic capping.

Delineating genotypes and phenotypes of individual cells from long-read single cell transcriptomes.

Single-cell nanopore sequencing of full-length mRNAs (scNanoRNAseq) is transforming singlecell multi-omics studies. However, challenges include computational complexity and dependence on short-read curation. To address this, we developed a comprehensive toolkit, scNanoGPS to calculate same-cell genotypes-phenotypes without short-read guidance. We applied scNanoGPS onto 23,587 long-read transcriptomes from 4 tumors and 2 cell lines. Standalone, scNanoGPS accurately deconvoluted error-prone long-reads into single-cells and single-molecules. Further, scNanoGPS simultaneously accessed both phenotypes (expressions/isoforms) and genotypes (mutations) of individual cells. Our analyses revealed that tumor and stroma/immune cells often expressed significantly distinct combinations of isoforms (DCIs). In a kidney tumor, we identified 924 genes with DCIs involved in cell-type-specific functions such as PDE10A in tumor cells and CCL3 in lymphocytes. Moreover, transcriptome-wide mutation analyses identified many cell-type-specific mutations including VEGFA mutations in tumor cells and HLA-A mutations in immune cells, highlighting critical roles of different populations in tumors. Together, scNanoGPS facilitates applications of single-cell long-read sequencing.

The Dawning of a New Enterprise: RNA Therapeutics for the Skin.

Despite being under development for decades, RNA therapeutics have only recently emerged as viable drug platforms. The COVID-19 mRNA vaccines have demonstrated the promise and power of the platform technology. In response, novel RNA drugs are entering clinical trials at an accelerating rate. As the skin is the largest and most accessible organ, it has always been a preferred target for drug discovery. This holds true for RNA therapies as well, and multiple candidate RNA-based drugs are currently in development for an array of skin conditions. In this mini review, we catalog the RNA therapies currently in clinical trials for different dermatological diseases. We summarize the main types of RNA-related drugs and use examples of drugs currently in development to illustrate their key mechanism of action.

Copan microFLOQ® Direct Swab collection of bloodstains, saliva, and semen on cotton cloth.

The microFLOQ® Direct Swab was tested by sampling diluted blood, semen, and saliva stains deposited on cotton cloth. DNA typing was performed using the PowerPlex® Fusion 6C System by direct PCR or a modified direct PCR. Direct PCR of swabs sampled the center of a stain, compared to their respective edge samplings, and had higher profile completeness and total relative fluorescent units (RFU) for all dilutions of blood and semen stains tested. The modified direct PCR used template DNA eluted from the swab head using the Casework Direct Kit, Custom and washes either contained 1-thioglycerol (TG) additive or no TG. Modified direct PCR had mixed results for blood, saliva, and semen stains, with semen stains showing significant differences in profile completeness (5% and 1%) and total RFU (neat, 5% and 1%) with the addition of TG to the Casework Direct Reagent. No significant difference was seen in any dilution of blood or saliva stains processed with the modified direct PCR, but profile completeness and total RFU were improved overall compared to stains swabbed with cotton swabs or 4N6FLOQSwabs™. This study supports the hypothesis that the microFLOQ® Direct Swab is able to collect minute amounts of DNA from cotton cloth and may be considered as an alternate pre-screening methodology in forensic biology casework.

Reverse Complement PCR: A novel one-step PCR system for typing highly degraded DNA for human identification.

Reverse Complement PCR (RC-PCR) is an innovative, one-step PCR target enrichment technology adapted for the amplification of highly degraded (fragmented) DNA. It provides simultaneous amplification and tagging of a targeted sequence construct in a single, closed-tube assay. A human identification (HID) RC-PCR panel was designed targeting 27 identity single nucleotide polymorphisms (SNPs) generating targets only 50 base pairs in length. In a single reaction, the complete sequencing construct is produced which is essential for massively parallel sequencing (MPS) library preparation, thus reducing time and labor as well as minimizing the risk of sample carry-over or other forms of contamination. The RC-PCR system was evaluated and found to produce reliable and concordant variant calls. Also, the RC-PCR system demonstrated to have substantial sensitivity of detection with a majority of alleles detected at 60 pg of input DNA and robustness in tolerating known PCR inhibitors. The RC-PCR system may be an effective alternative to current forensic genetic methods in the analysis of highly degraded DNA.