SARS-CoV-2 papain-like protease inhibits ISGylation of the viral nucleocapsid protein to evade host anti-viral immunity.

A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes mild-to-severe respiratory symptoms, including acute respiratory distress. Despite remarkable efforts to investigate the virological and pathological impacts of SARS-CoV-2, many of the characteristics of SARS-CoV-2 infection still remain unknown. The interferon-inducible ubiquitin-like protein ISG15 is covalently conjugated to several viral proteins to suppress their functions. It was reported that SARS-CoV-2 utilizes its papain-like protease (PLpro) to impede ISG15 conjugation, ISGylation. However, the role of ISGylation in SARS-CoV-2 infection remains unclear. We aimed to elucidate the role of ISGylation in SARS-CoV-2 replication. We observed that the SARS-CoV-2 nucleocapsid protein is a target protein for the HERC5 E3 ligase-mediated ISGylation in cultured cells. Site-directed mutagenesis reveals that the residue K374 within the C-terminal spacer B-N3 (SB/N3) domain is required for nucleocapsid-ISGylation, alongside conserved lysine residue in MERS-CoV (K372) and SARS-CoV (K375). We also observed that the nucleocapsid-ISGylation results in the disruption of nucleocapsid oligomerization, thereby inhibiting viral replication. Knockdown of ISG15 mRNA enhanced SARS-CoV-2 replication in the SARS-CoV-2 reporter replicon cells, while exogenous expression of ISGylation components partially hampered SARS-CoV-2 replication. Taken together, these results suggest that SARS-CoV-2 PLpro inhibits ISGylation of the nucleocapsid protein to promote viral replication by evading ISGylation-mediated disruption of the nucleocapsid oligomerization.IMPORTANCEISG15 is an interferon-inducible ubiquitin-like protein that is covalently conjugated to the viral protein via specific Lys residues and suppresses viral functions and viral propagation in many viruses. However, the role of ISGylation in SARS-CoV-2 infection remains largely unclear. Here, we demonstrated that the SARS-CoV-2 nucleocapsid protein is a target protein for the HERC5 E3 ligase-mediated ISGylation. We also found that the residue K374 within the C-terminal spacer B-N3 (SB/N3) domain is required for nucleocapsid-ISGylation. We obtained evidence suggesting that nucleocapsid-ISGylation results in the disruption of nucleocapsid-oligomerization, thereby suppressing SARS-CoV-2 replication. We discovered that SARS-CoV-2 papain-like protease inhibits ISG15 conjugation of nucleocapsid protein via its de-conjugating enzyme activity. The present study may contribute to gaining new insight into the roles of ISGylation-mediated anti-viral function in SARS-CoV-2 infection and may lead to the development of more potent and selective inhibitors targeted to SARS-CoV-2 nucleocapsid protein.

Usefulness of pre- and post-stent optical frequency domain imaging findings in the prediction of periprocedural cardiac troponin elevation in patients with coronary artery disease.

Cholesterol crystals (CCs) are frequently found in high-risk plaques, such as thin-capped fibroatheromas. The purpose of this study was to investigate the associations of CCs, plaque morphologies, and post-stent optical frequency domain imaging (OFDI) findings with periprocedural cardiac troponin (cTn) elevation in patients treated with percutaneous coronary intervention (PCI). This study consists of 119 patients with stable coronary artery disease (CAD) with normal cTn levels who underwent OFDI-guided PCI. Periprocedural cTn elevation was defined as an elevation of cTn ≥ × 5 times the upper reference limit after PCI. Pre- and post-stent OFDI findings, including fibrous cap thickness (FCT), presence of CCs, and parameters for lipid and calcification were analyzed. A total of 37 (31%) patients were classified into the periprocedural cTn elevation group. Compared with lesions without CCs, lesions exhibiting CCs had thinner FCT, larger lipid arc, and longer lipid length, and were more likely to have irregular protrusion and in-stent thrombus (all p < 0.05). For pre-stent OFDI features, FCT < 82 µm [odds ratio (OR) 4.11; p = 0.003] and CCs (OR 3.23; p = 0.017) were associated with periprocedural cTn elevation. For post-stent OFDI features, in-stent dissection (OR 3.08; p = 0.035) and in-stent thrombus (OR 7.98; p = 0.002) were independent predictors of cTn elevation. The combination of CCs and FCT < 82 µm showed increased risk of periprocedural cTn elevation (OR 7.22; p = 0.002). OFDI-guided PCI provides unique insight into the mechanism for periprocedural cTn elevation in CAD patients.

Prognostic value of high-sensitive troponin T for predicting cardiovascular events after atrial fibrillation ablation.

BACKGROUND AND OBJECTIVES: This study aimed to evaluate the utility of high-sensitive troponin T (hs-TnT) for predicting AF recurrence and major adverse cardiovascular events (MACE) after AF ablation. METHODS AND RESULTS: A total of 227 consecutive patients with AF (mean age, 66 ± 10 years; persistent AF, n = 98) who underwent an initial ablation were enrolled. We measured hs-TnT before AF ablation and divided the patients into three groups according to the hs-TnT level: low, lesser than or equal to 0.005 µg/L (n = 54); medium, 0.006-0.013 µg/L (n = 127); and high, greater than or equal to0.014 µg/L (n = 46). We evaluated the composite endpoint of AF recurrence or MACE (including death, stroke, acute coronary syndrome, and heart failure hospitalization) after the ablation. The median hs-TnT level was 0.008 µg/L. The values of chronic kidney disease prevalence, CHA2 DS2 -VASc score, B-type natriuretic peptide level, and left atrial diameter were the highest in the high hs-TnT group among the three groups. During a mean follow-up of 15 ± 8 months, AF recurrence and MACE occurred in 56 (25%) and 9 (4%) patients, respectively. The high hs-TnT group had the highest incidence of AF recurrence and MACE among the three groups (high: 39% and 15%, medium: 22% and 2%, and low: 19% and 0%, respectively; log-rank P < .05). In multivariate analysis, hs-TnT greater than or equal to 0.014 µg/L and persistent AF were independent predictors of the composite endpoint. CONCLUSION: Hs-TnT may be a useful marker for predicting AF recurrence or MACE after AF ablation.

Prognostic significance of renal dysfunction and its change pattern on outcomes in patients with acute coronary syndrome treated with emergent percutaneous coronary intervention.

Renal dysfunction and its change pattern are associated with short- and long-term mortality. However, it remains to be investigated whether or not worsening renal function (WRF) defined by baseline renal function identified from different time points would provide prognostic implication on outcomes in acute coronary syndrome (ACS) patients. This study consists of 334 ACS patients (mean age 68 ± 11 years, 75% male) treated with emergent percutaneous coronary intervention (PCI). Estimated glomerular filtration rate (eGFR) was evaluated on baseline, during hospitalization, at discharge, and at 3-month follow-up. WRF was defined as a relative decrease of eGFR > 20% at 3 months using baseline eGFR identified from different time points. The primary end point was a composite event of major cardiovascular events (MACE), including all-cause death, ACS, and heart failure hospitalization. The associations of chronic kidney disease (CKD), acute kidney injury (AKI), and WRF with MACE were evaluated. During a mean follow-up of 3.3 ± 1.7 years, a total of 64 MACE were observed. Multivariable analysis revealed that CKD (hazard ratio 2.16; p = 0.018) and AKI (hazard ratio 1.95; p = 0.030) were independent predictors of MACE, but WRF did not remain as an independent predictor of MACE (p = 0.208). The highest risk was observed in AKI patients with CKD when stratified by the presence or absence of CKD and AKI. In ACS patients treated with emergent PCI, this study demonstrated that CKD and AKI were independent predictors of MACE, while there was no independent relationship between WRF and MACE.

Diagnostic value of electrocardiographic P-wave characteristics in atrial fibrillation recurrence and tachycardia-induced cardiomyopathy after catheter ablation.

Abnormal P-wave characteristics were reportedly associated with left ventricular interstitial fibrosis as defined by cardiac magnetic resonance images. The objective of this study is to investigate the utility of P-wave characteristics to predict atrial fibrillation (AF) recurrence and the recovery of left ventricular systolic dysfunction (LVSD) after catheter ablation (CA) for AF. Two hundred and five AF patients (109 paroxysmal and 96 persistent) who underwent CA were enrolled. We measured maximum P-wave duration (max PWD) and P-wave terminal force in lead V1 (PTFV1) calculated as a product of P-wave terminal amplitude (PTaV1) and duration (PTdV1) in lead V1 during sinus rhythm. AF recurrence was noted in 50 patients at 12 months after CA. Patients with AF recurrence had a higher prevalence of persistent AF, a larger left atrial volume, and a longer max PWD than those without. We divided the patients into 2 groups: 156 patients with left ventricular ejection fraction (LVEF) > 45% and 49 patients with LVEF ≤ 45% (Low-EF group). In Low-EF group, tachycardia-induced cardiomyopathy (TIC) was defined as improvement in LVEF ≥ 15% or LVEF ≥ 50% at 5 months after CA. TIC and non-TIC groups consisted of 37 and 12 patients, respectively. Max PWD, PTFV1, PTdV1, and PTaV1 were significantly greater in non-TIC-group than in TIC-group. PTFV1 had the highest diagnostic accuracy to discriminate between TIC and no-TIC-groups; cut-off value for PTFV1 was determined as 56.7 mV ms (area under the ROC curve = 0.80; 75% sensitivity; and 76% specificity). Max PWD was a useful predictor of AF recurrence and the complete recovery of LVSD after CA. PTFV1 had the highest diagnostic accuracy to discriminate between TIC and no-TIC-groups.

Successful catheter ablation improves exercise tolerance in persistent atrial fibrillation patients, especially those with reduced ventricular contraction, preserved atrial function, or a high CHADS2 score.

BACKGROUND: It has been reported that rhythm control for persistent atrial fibrillation (per-AF) patients by catheter ablation improves their exercise tolerance, subjective symptoms, and quality of life (QoL). However, clinical factors that can predict future improvement of exercise capacity after successful catheter ablation in per-AF patients are unclear. METHODS: This study consisted of 62 patients (mean age 65.6 ±â€¯8.7 years, 77% males) with per-AF who underwent catheter ablation from June 2017 to May 2018. All patients were subjected to extended pulmonary vein isolation. Exercise tolerance was evaluated using a symptom-limited cardiopulmonary exercise test before and 3 months after catheter ablation. Primary endpoints were QoL measurements using an original questionnaire and functional assessments performed at 3 months. RESULTS: The questionnaire revealed significant improvement in QoL after catheter ablation (minimal metabolic equivalents occurring symptoms: from 5.48 ±â€¯1.14 to 5.64 ±â€¯1.06; p = 0.01). Endurance exercise characteristics improved significantly after catheter ablation, demonstrated by a shift in anaerobic threshold (from 13.3 ±â€¯3.0 to 15.2 ±â€¯3.3 ml/kg/min; p < 0.001), peak oxygen uptake (from 19.1 ±â€¯4.6 to 22.5 ±â€¯5.0 ml/kg/min; p < 0.001), and minute ventilation vs carbon dioxide production slope (from 28.3 ±â€¯6.1 to 25.7 ±â€¯3.8; p < 0.001). Multivariate Cox regression analysis revealed that a decreased left ventricular ejection fraction, high left atrial appendage velocity, and high CHADS2 score were identified as independent predictors of anaerobic threshold and a peak value of oxygen uptake with more than 20% improvement. CONCLUSIONS: Catheter ablation for per-AF patients improves QoL and exercise tolerance. The effect was especially remarkable in patients with reduced ventricular function, those who had a preserved atrial function, or those at high risk of thromboembolism.