Small molecules block the interaction between porcine reproductive and respiratory syndrome virus and CD163 receptor and the infection of pig cells.

BACKGROUND: Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically devastating diseases affecting the pork industry globally. PRRS is caused by PRRS virus (PRRSV). Currently there are no effective treatments against this swine disease. METHODS: Through artificial intelligence molecular screening, we obtained a set of small molecule compounds predicted to target the scavenger receptor cysteine-rich domain 5 (SRCR5) of CD163, which is a cell surface receptor specific for PRRSV infection. These compounds were screened using a cell-based bimolecular fluorescence complementation (BiFC) assay, and the function of positive hit was further evaluated and validated by PRRSV-infection assay using porcine alveolar macrophages (PAMs). RESULTS: Using the BiFC assay, we identified one compound with previously unverified function, 4-Fluoro-2-methyl-N-[3-(3-morpholin-4-ylsulfonylanilino)quinoxalin-2-yl]benzenesulfonamide (designated here as B7), that significantly inhibits the interaction between the PRRSV glycoprotein (GP2a or GP4) and the CD163-SRCR5 domain. We further demonstrated that compound B7 inhibits PRRSV infection of PAMs, the primary target of PRRSV in a dose-dependent manner. B7 significantly inhibited the infection caused by both type I and type II PRRSV strains. Further comparison and functional evaluation of chemical compounds structurally related to B7 revealed that the 3-(morpholinosulfonyl)aniline moiety of B7 or the 3-(piperidinylsulfonyl)aniline moiety in a B7 analogue is important for the inhibitory function against PRRSV infection. CONCLUSIONS: Our study identified a novel strategy to potentially prevent PRRSV infection in pigs by blocking the PRRSV-CD163 interaction with small molecules.

Increased Risk of Cryptogenic Stroke Associated with Patent Foramen Ovale in Young Adults.

Ischemic stroke is defined as a reduction in blood flow to brain tissue that results in the deterioration and death of neurons in a matter of minutes. While often seen in older patients with a history of atherosclerosis of the major arteries, a subset of ischemic strokes occur in younger individuals with minimal to no prior risk factors. Further evaluation of these unknown, or cryptogenic, strokes has yielded positive findings of a patent foramen ovale (PFO) in a concerning number of cases. Cryptogenic strokes attributable to PFO present an important clinical occurrence because they do not fit the typical template regarding those most at risk for such acutely devastating outcomes, making their identification uniquely important for both immediate and long-term patient care.  A 20-year-old Hispanic female presented to the emergency department for evaluation of neurological symptoms indicating obstruction of a major cerebral vessel. After being placed on stroke alert and found to have an embolus occluding the left middle cerebral artery (MCA) via non-contrast computed tomography (CT), tissue plasminogen activator (tPA) was administered, and mechanical thrombectomy was performed to restore blood flow. Following stabilization, further testing done on the patient revealed a substantial PFO that likely allowed for the crossing of an embolus from venous blood returning to the heart directly into the arterial circulation. The patient opted for cardiac monitor placement and has remained asymptomatic to this point while awaiting surgical repair. This case demonstrates an unusual presentation of ischemic stroke in a young individual with no reported risk factors and highlights the importance of screening for large PFO in patients prior to a serious cerebrovascular accident. It is our hope that highlighting this case may heighten awareness of this condition and allow for timely recognition from medical personnel who may encounter this same medical emergency in the future.

NANOG and LIN28 dramatically improve human cell reprogramming by modulating LIN41 and canonical WNT activities.

Human cell reprogramming remains extremely inefficient and the underlying mechanisms by different reprogramming factors are elusive. We found that NANOG and LIN28 (NL) synergize to improve OCT4, SOX2, KLF4 and MYC (OSKM)-mediated reprogramming by ∼76-fold and shorten reprogramming latency by at least 1 week. This synergy is inhibited by GLIS1 but reinforced by an inhibitor of the histone methyltransferase DOT1L (iDOT1L) to a ∼127-fold increase in TRA-1-60-positive (+) iPSC colonies. Mechanistically, NL serve as the main drivers of reprogramming in cell epithelialization, the expression of Let-7 miRNA target LIN41, and the activation of canonical WNT/ß-CATENIN signaling, which can be further enhanced by iDOT1L treatment. LIN41 overexpression in addition to OSKM similarly promoted cell epithelialization and WNT activation in reprogramming, and a dominant-negative LIN41 mutation significantly blocked NL- and iDOT1L-enhanced reprogramming. We also found that NL- and iDOT1L-induced canonical WNT activation facilitates the initial development kinetics of iPSCs. However, a substantial increase in more mature, homogeneous TRA-1-60+ colony formation was achieved by inhibiting WNT activity at the middle-to-late-reprogramming stage. We further found that LIN41 can replace LIN28 to synergize with NANOG, and that the coexpression of LIN41 with NL further enhanced the formation of mature iPSCs under WNT inhibition. Our study established LIN41 and canonical WNT signaling as the key downstream effectors of NL for the dramatic improvement in reprogramming efficiency and kinetics, and optimized a condition for the robust formation of mature human iPSC colonies from primary cells.This article has an associated First Person interview with the first author of the paper.

FOXH1 Is Regulated by NANOG and LIN28 for Early-stage Reprogramming.

FOXH1 is a primitive-streak specifier and ACTIVIN co-effector that plays an important role in development, and positively regulates the generation of human induced pluripotent stem cells (iPSCs) from somatic cells by OCT4, SOX2, KLF4, and MYC (OSKM) transduction. However, the mechanism and upstream regulation for FOXH1 expression in reprogramming are unclear. We found FOXH1 expression plays a significant role to enhance epithelial marker and suppress mesenchymal gene expression in OSKM-mediated human cell reprogramming. Furthermore, NANOG and LIN28 (NL) co-stimulate FOXH1 expression, which correlates with the enhanced reprogramming efficiency by NL-factors. FOXH1 expression is also stimulated by a specific inhibitor for H3K79 methyltransferase DOT1L (iDOT1L) but not by inhibition of the canonical WNT signaling. We further show that blocking endogenous FOXH1 expression eliminates the enhanced reprogramming effect by NL and iDOT1L. However, overexpressing FOXH1 in NL plus iDOT1L condition results in significantly reduced TRA-1-60 positively expressed cells and decreases pluripotent marker expression in reprogramming. Our study elucidated an essential role for properly stimulated FOXH1 expression by NANOG, LIN28, and H3K79 demethylation for dramatic enhancement of reprograming.