Coronavirus disease 2019 (COVID-19) is mainly an infectious disease of the respiratory system transmitted through air droplets, and pulmonary symptoms constitute main presentations of this disease. However, COVID-19 demonstrates a clinically diverse manifestation ranging from asymptomatic presentation to critically illness with severe pneumonia, acute respiratory distress syndrome, respiratory failure, or multiple organ failure. Accumulating evidences demonstrated that COVID-19 has extrapulmonary involvement, including neurological, smelling sensation, cardiovascular, digestive, hepatobiliary, renal, endocrinologic, dermatologic system, and others. Over a third of COVID-19 patients manifest a wide range of neurological symptoms involving the central/peripheral nervous system. Underlying cardiovascular comorbidities were associated with detrimental outcomes, meanwhile the occurrence of cardiovascular complications correlate to poor survival. Gastrointestinal symptoms frequently occur and have been associated with a longer period of illness. Impaired hepatic functions were associated with the severity of the disease. Higher rate of acute kidney injury was reported in critically ill patients with COVID-19. Endocrinologic presentations of COVID-19 include exacerbating hyperglycemia, euglycemic ketosis, and diabetic ketoacidosis. The most common cutaneous manifestation was acro-cutaneous (pernio or chilblain-like) lesions, and other skin lesions consist of maculopapular rash, vesicular lesions, livedoid/necrotic lesions, exanthematous rashes, and petechiae. This review article summarized the general clinical signs and symptoms, radiologic features, and disease manifestation with progression in patients with COVID-19.

Lung cancer is the leading cause of cancer-related mortality worldwide, and its tumorigenesis involves the accumulation of genetic and epigenetic events in the respiratory epithelium. Epigenetic modifications, such as DNA methylation, RNA modification, and histone modifications, have been widely reported to play an important role in lung cancer development and in other pulmonary diseases. Whereas the functionality of DNA and chromatin modifications referred to as epigenetics is widely characterized, various modifications of RNA nucleotides have recently come into prominence as functionally important. N6-methyladosine (m6A) is the most prevalent internal modification in mRNAs, and its machinery of writers, erasers, and readers is well-characterized. However, several other nucleotide modifications of mRNAs and various noncoding RNAs have also been shown to play an important role in the regulation of biological processes and pathology. Such epitranscriptomic modifications play an important role in regulating various aspects of RNA metabolism, including transcription, translation, splicing, and stability. The dysregulation of epitranscriptomic machinery has been implicated in the pathological processes associated with carcinogenesis including uncontrolled cell proliferation, migration, invasion, and epithelial-mesenchymal transition. In recent years, with the advancement of RNA sequencing technology, high-resolution maps of different modifications in various tissues, organs, or disease models are being constantly reported at a dramatic speed. This facilitates further understanding of the relationship between disease development and epitranscriptomics, shedding light on new therapeutic possibilities. In this review, we summarize the basic information on RNA modifications, including m6A, m1A, m5C, m7G, pseudouridine, and A-to-I editing. We then demonstrate their relation to different kinds of lung diseases, especially lung cancer. By comparing the different roles RNA modifications play in the development processes of different diseases, this review may provide some new insights and offer a better understanding of RNA epigenetics and its involvement in pulmonary diseases.

Inherited retinal dystrophies (IRDs) are a group of rare eye diseases caused by gene mutations that result in the degradation of cone and rod photoreceptors or the retinal pigment epithelium. Retinal degradation progress is often irreversible, with clinical manifestations including color or night blindness, peripheral visual defects and subsequent vision loss. Thus, gene therapies that restore functional retinal proteins by either replenishing unmutated genes or truncating mutated genes are needed. Coincidentally, the eye’s accessibility and immune-privileged status along with major advances in gene identification and gene delivery systems heralded gene therapies for IRDs. Among these clinical trials, voretigene neparvovec-rzyl (Luxturna), an adeno-associated virus vector-based gene therapy drug, was approved by the FDA for treating patients with confirmed biallelic RPE65 mutation-associated Leber Congenital Amaurosis (LCA) in 2017. This review includes current IRD gene therapy clinical trials and further summarizes preclinical studies and therapeutic strategies for LCA, including adeno-associated virus-based gene augmentation therapy, 11-cis-retinal replacement, RNA-based antisense oligonucleotide therapy and CRISPR-Cas9 gene-editing therapy. Understanding the gene therapy development for LCA may accelerate and predict the potential hurdles of future therapeutics translation. It may also serve as the template for the research and development of treatment for other IRDs.

Epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells is related to the pathogenesis of various retinopathies including age-related macular degeneration (AMD). Oxidative stress is the major factor that induces degeneration of RPE cells associated with the etiology of AMD. Sodium iodate (NaIO₃) generates intracellular reactive oxygen species (ROS) and is widely used to establish a model of AMD due to the selective induction of retinal degeneration. This study was performed to clarify the effects of multiple NaIO₃-stimulated signaling pathways on EMT in RPE cells. The EMT characteristics in NaIO₃-treated human ARPE-19 cells and RPE cells of the mouse eyes were analyzed. Multiple oxidative stress-induced modulators were investigated and the effects of pre-treatment with Ca²⁺ chelator, extracellular signal-related kinase (ERK) inhibitor, or epidermal growth factor receptor (EGFR) inhibitor on NaIO₃-induced EMT were determined. The efficacy of post-treatment with ERK inhibitor on the regulation of NaIO₃-induced signaling pathways was dissected and its role in retinal thickness and morphology was evaluated by using histological cross-sections and spectral domain optical coherence tomography. We found that NaIO₃ induced EMT in ARPE-19 cells and in RPE cells of the mouse eyes. The intracellular ROS, Ca²⁺, endoplasmic reticulum (ER) stress marker, phospho-ERK, and phospho-EGFR were increased in NaIO₃-stimulated cells. Our results showed that pre-treatment with Ca²⁺ chelator, ERK inhibitor, or EGFR inhibitor decreased NaIO₃-induced EMT, interestingly, the inhibition of ERK displayed the most prominent effect. Furthermore, post-treatment with FR180204, a specific ERK inhibitor, reduced intracellular ROS and Ca²⁺ levels, downregulated phospho-EGFR and ER stress marker, attenuated EMT of RPE cells, and prevented structural disorder of the retina induced by NaIO₃. ERK is a crucial regulator of multiple NaIO₃-induced signaling pathways that coordinate EMT program in RPE cells. Inhibition of ERK may be a potential therapeutic strategy for the treatment of AMD.

Lung cancer (LC) causes the majority of cancer-related deaths. Circular RNAs (circRNAs) were reported to play roles in cancers by targeting pro- and anti-oncogenic miRNAs. However, the mechanisms of circRNAs in LC progression and their prognostic value of treatment response remain unclear. By using next generation sequencing (NGS) of LC cell lines’ transcriptomes, we identified highly overexpressed hsa_circ_0000190 and hsa_circ_000164 as potential biomarkers. By using the highly sensitive RT-ddPCR method, these circRNAs were shown to be secreted by cell lines and were detected in human blood. Clinical validation by RT-ddPCR was carried out on 272 (231 LC patients and 41 controls) blood samples. Higher hsa_circ_0000190 levels were associated with larger tumor size (p < 0.0001), worse histological type of adenocarcinoma (p = 0.0028), later stage (p < 0.0001), more distant metastatic organs (p = 0.0039), extrathoracic metastasis (p = 0.0004), and poor survival (p = 0.047) and prognosis. Using liquid biopsy-based RT-ddPCR, we discovered the correlation between increased hsa_circ_0000190 plasma level (p < 0.0001) and higher programmed death-ligand 1 (PD-L1) level in tumor (p = 0.0283). Notably, long-term follow-up of the immunotherapy treated cases showed that upregulated plasma hsa_circ_0000190 level correlated with poor response to systemic therapy and immunotherapy (p = 0.0002, 0.0058, respectively). Secretory circRNAs are detectable in blood by LB-based RT-ddPCR and may serve as blood-based biomarkers to monitor disease progression and treatment efficacy.

Background: Glioblastoma (GBM) is the most lethal brain tumor characterized by high morbidity and limited treatment options. Tumor malignancy is usually associated with the epigenetic marks, which coordinate gene expression to ascertain relevant phenotypes. One of such marks is m6A modification of RNA, whose functional effects are dependent on the YTH family m6A reader proteins. Methods and results: In this study, we investigated the expression of five YTH family proteins in different GBM microarray datasets from the Oncomine database, and identified YTHDF1 as the most highly overexpressed member of this family in GBM. By performing the knockdown of YTHDF1 in a GBM cell line, we found that it positively regulates proliferation, chemoresistance and cancer stem cell-like properties. Musashi-1 (MSI1) is a postranscriptional gene expression regulator associated with high oncogenicity in GBM. By knocking down and overexpressing MSI1, we found that it positively regulates YTHDF1 expression. The inhibitory effects imposed on the processes of proliferation and migration by YTHDF1 knockdown were shown to be partially rescued by concomitant overexpression of MSI1. MSI1 and YTHDF1 were shown to be positively correlated in clinical glioma samples, and their concomitant upregulation was associated with decreased survival of glioma patients. We identified the direct regulation of YTHDF1 by MSI1. Conclusions: Given the fact that both proteins are master regulators of gene expression, and both of them are unfavorable factors in GBM, we suggest that in any future studies aimed to uncover the prognostic value and therapy potential, these two proteins should be considered together.