Early suppression of antiviral host response and protocadherins by SARS-CoV-2 Spike protein in THP-1-derived macrophage-like cells.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease-19 (COVID-19). The spike protein (S) of SARS-CoV-2 plays a crucial role in mediating viral infectivity; hence, in an extensive effort to curb the pandemic, many urgently approved vaccines rely on the expression of the S protein, aiming to induce a humoral and cellular response to protect against the infection. Given the very limited information about the effects of intracellular expression of the S protein in host cells, we aimed to characterize the early cellular transcriptomic changes induced by expression of the S protein in THP-1-derived macrophage-like cells. Results showed that a wide variety of genes were differentially expressed, products of which are mainly involved in cell adhesion, homeostasis, and most notably, antiviral and immune responses, depicted by significant downregulation of protocadherins and type I alpha interferons (IFNAs). While initially, the levels of IFNAs were higher in the medium of S protein expressing cells, the downregulation observed on the transcriptomic level might have been reflected by no further increase of IFNA cytokines beyond the 5 h time-point, compared to the mock control. Our study highlights the intrinsic pathogenic role of the S protein and sheds some light on the potential drawbacks of its utilization in the context of vaccination strategies.

Ventricular Tachycardia Triggered by Loperamide and Famotidine Abuse.

A 32-year-old male developed recurrent ventricular tachycardia after taking mega doses of loperamide and famotidine in order to experience an opiate-like euphoric effect. He was taking up to 200 mg of loperamide and multiple doses of famotidine each day. He developed palpitations and syncope. Electrocardiography demonstrated ventricular tachycardia and QT interval prolongation (corrected QT interval was 597 ms). He was diagnosed with loperamide-induced QT prolongation resulting in incessant ventricular tachycardia. Loperamide was discontinued, and he was treated with electrolyte replacement, supportive care, and monitoring. After 5 days, his electrocardiogram (ECG) normalized and he had no more ventricular tachycardia. A Naranjo assessment score of 8 was obtained, indicating a probable relationship between QT prolongation and his use of loperamide. Large doses of loperamide can cause QT interval prolongation and life-threatening arrhythmias. These effects may be accentuated when histamine-2 receptor blockers are also abused.

Mutation of IGFBP7 causes upregulation of BRAF/MEK/ERK pathway and familial retinal arterial macroaneurysms.

Insulin-like growth factor binding proteins (IGFBPs) play important physiological functions through the modulation of IGF signaling as well as IGF-independent mechanisms. Despite the established role of IGFs in development, a similar role for the seven known IGFBPs has not been established in humans. Here, we show that an autosomal-recessive syndrome that consists of progressive retinal arterial macroaneurysms and supravalvular pulmonic stenosis is caused by mutation of IGFBP7. Consistent with the recently established inhibitory role of IGFBP7 on BRAF signaling, the BRAF/MEK/ERK pathway is upregulated in these patients, which may explain why the cardiac phenotype overlaps with other disorders characterized by germline mutations in this pathway. The retinal phenotype appears to be mediated by a role in vascular endothelium, where IGFBP7 is highly expressed.