Over the last three years, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related health crisis has claimed over six million lives and caused USD 12 trillion losses to the global economy. SARS-CoV-2 continuously mutates and evolves with a high basic reproduction number (R0), resulting in a variety of clinical manifestations ranging from asymptomatic infection to acute respiratory distress syndrome (ARDS) and even death. To gain a better understanding of coronavirus disease 2019 (COVID-19), it is critical to investigate the components that cause various clinical manifestations. Single-cell sequencing has substantial advantages in terms of identifying differentially expressed genes among individual cells, which can provide a better understanding of the various physiological and pathological processes. This article reviewed the use of single-cell transcriptomics in COVID-19 research, examined the immune response disparities generated by SARS-CoV-2, and offered insights regarding how to improve COVID-19 diagnosis and treatment plans.

Bladder cancer (BC) is the 10th most commonly diagnosed cancer worldwide, its carcinogenesis mechanism has not been fully elucidated. BC is able to induce natural killer (NK) cells dysfunction and escape their immune surveillance. The present study found that exosome plays an important role in BC induced NK cell dysfunction by impairing viability, and inhibit the cytotoxicity of NK cell on target cells. Meanwhile, BC derived exosome inhibited the expression of important functional receptors NKG2D, NKp30, and CD226 on NK cells and the secretion of perforin and granzyme-B. Through high-throughput sequencing, the critical miRNAs with high expression in BC exosomes were identified. Furthermore, after Dual-Luciferase reporter assay and transfection experiment, miR-221-5p and miR-186-5p was confirmed can interfere the stability of mRNAs of DAP10, CD96, and perforin gene in NK cells and may be the potential targets using in the therapeutic application of BC.