We investigated the association between circulating microRNAs (miRNAs) potentially involved in the lung inflammatory process and fibrosis development among COVID-19-related acute respiratory distress syndrome (ARDS) survivors. At 4 ± 2 months from clinical recovery, COVID-19-related ARDS survivors matched for age, sex, and clinical characteristics underwent chest high-resolution computerized tomography (HRCT) and were selected based on imaging pattern evolution into fully recovered (N = normal), pulmonary opacities (PO) and fibrosis-like lesions (FL). Based on the previous literature, we performed plasma miRNA profiling of exosomal miRNAs belonging to the NLRP3-inflammasome platform with validated (miR-17-5p, miR-223-3p) and putative targets (miR-146a-5p), miRNAs involved in the post-transcriptional regulation of acute phase cytokines (miR128-3p, miR3168, miR125b-2-3p, miR106a-5p), miRNAs belonging to the NLRP4-inflammasome platform (miR-141-3p) and miRNAs related to post-transcriptional regulation of the fibrosis process (miR-21-5p). miR-17-5p, miR-223-3p, and miR-146a-5p were significantly down-regulated in patients with FL when compared to patients with PO. miR-146a-5p was also down-regulated in patients with FL than in N. The expression of the remaining miRNAs did not differ by group. In patients with long-term pulmonary radiological sequelae following COVID-19-related ARDS, a down-regulation of miR-17-5p, miR-146a-3p, and miR-223-3p correlated to fibrosis development in patients showing persistent hyper-reactivity to inflammatory stimulation. Our results support the hypothesis that NLRP3-Inflammasome could be implicated in the process of fibrotic evolution of COVID-19-associated ARDS.

A 29‐year‐old Moroccan with oculocutaneous albinism presented with a history of exertional dyspnea, recurrent epistaxis, and bacterial infections, raising suspicion of Hermansky–Pudlak syndrome (HPS). Further evaluation revealed neutropenia, impaired platelet function, pulmonary fibrosis, and mild pulmonary hypertension. An ECG identified ventricular pre‐excitation with a postero‐septal right accessory pathway, consistent with Wolff–Parkinson–White (WPW) syndrome. Genetic testing confirmed a homozygous mutation in the AP3B1 gene and a diagnosis of Type 2 HPS (HPS‐2) was made. HPS‐2 is an extremely rare disorder, and to our knowledge, the co‐occurrence of WPW syndrome has not been previously reported in literature. We propose a potential causal link between these two conditions, as mutations in the AP3B1 gene—which encodes the beta subunit of the adapter protein 3 trafficking complex—result in mistrafficking of transmembrane proteins from the endosomal and trans‐Golgi network to lysosomes and endosome–lysosome‐related organelles. Specifically, the dysfunction of a transmembrane protein, namely the lysosome‐associated membrane protein 2 (LAMP‐2), has been implicated in the development of cardiac accessory pathways, as seen in Danon disease. We hypothesize that individuals with HPS‐2 may have a genetic predisposition to WPW syndrome, and this hypothesis should be investigated in further studies.

Background: There is limited understanding of the pathophysiology of post-acute pulmonary sequelae in COVID-19-associated acute respiratory distress syndrome (ARDS). We aimed at investigating the association of circulating microRNAs (miRNAs) involved in post-transcriptional regulation of NLRP3-inflammasome pathways and lung radiological features among COVID-19- associated ARDS survivors. Methods: We evaluated COVID-19-associated ARDS survivors at 4±2 months from clinical recovery. Patients were selected based on imaging pattern evolution according to chest high-resolution computerized tomography (HRCT) findings into “fully recovered” (FR), “pulmonary opacities” (PO) and “fibrosis-like lesions” (FL) according to radiological appearance. Plasma miRNA profiling was performed using real time quantitative polymerase chain reaction (RT-qPCR). The exosomal expression of NLRP3 inflammasome related miRNAs (miR-17-5p, miR-223-3p, miR-146a-5p) was evaluated. Results: 31 patients (33% men, mean age 60±6 years, mean BMI 31.1±6.6 Kg/m2) were selected for the present study. No statistically significant differences between FR, PO and FL patterns were observed according to clinical features. NLRP3-inflammasome-related miRNAs such as miR-17-5p, miR-223-3p and miR-146a-5p were significantly up-regulated in patients with PO when compared to patients with FL. miR-146a-5p was also up-regulated in patients with FL than in FR. Conclusions: In patients with long-term pulmonary radiological sequelae following COVID71 19- associated ARDS, a down-regulation of miRNAs inhibiting NLRP3 (miR-17-5p, miR-146a72 3p and miR-223-3p) correlated to fibrosis development in patients showing persistent hyper-reactivity to inflammatory stimulation. NLRP3-Inflammasome-related miRNAs could be a possible therapeutic target to prevent the fibrotic evolution of COVID-19-associated ARDS.