Human leukocyte antigen class I antibody-activated endothelium promotes CD206+ M2 macrophage polarization and MMP9 secretion through TLR4 signaling and P-selectin in a model of antibody-mediated rejection and allograft vasculopathy.

HLA donor-specific antibodies (DSA) elicit alloimmune responses against the graft vasculature, leading to endothelial cell (EC) activation and monocyte infiltration during antibody-mediated rejection (AMR). AMR promotes chronic inflammation and remodeling, leading to thickening of the arterial intima termed transplant vasculopathy or cardiac allograft vasculopathy (CAV) in heart transplants. Intragraft-recipient macrophages serve as a diagnostic marker in AMR; however, their polarization and function remain unclear. In this study, we utilized an in vitro Transwell coculture system to explore the mechanisms of monocyte-to-macrophage polarization induced by HLA I DSA-activated ECs. Anti-HLA I (IgG or F(ab')2) antibody-activated ECs induced the polarization of M2 macrophages with increased CD206 expression and MMP9 secretion. However, inhibition of TLR4 signaling or PSGL-1-P-selectin interactions significantly decreased both CD206 and MMP9. Monocyte adherence to Fc-P-selectin coated plates induced M2 macrophages with increased CD206 and MMP9. Moreover, Fc-receptor and IgG interactions synergistically enhanced active-MMP9 in conjunction with P-selectin. Transcriptomic analysis of arteries from DSA+CAV+ rejected cardiac allografts and multiplex-immunofluorescent staining illustrated the expression of CD68+CD206+CD163+MMP9+ M2 macrophages within the neointima of CAV-affected lesions. These findings reveal a novel mechanism linking HLA I antibody-activated endothelium to the generation of M2 macrophages which secrete vascular remodeling proteins contributing to AMR and CAV pathogenesis.

Spatial multiomics of arterial regions from cardiac allograft vasculopathy rejected grafts reveal novel insights into the pathogenesis of chronic antibody-mediated rejection.

Cardiac allograft vasculopathy (CAV) causes late graft failure and mortality after heart transplantation. Donor-specific antibodies (DSAs) lead to chronic endothelial cell injury, inflammation, and arterial intimal thickening. In this study, GeoMx digital spatial profiling was used to analyze arterial areas of interest (AOIs) from CAV+DSA+ rejected cardiac allografts (N = 3; 22 AOIs total). AOIs were categorized based on CAV neointimal thickening and underwent whole transcriptome and protein profiling. By comparing our transcriptomic data with that of healthy control vessels of rapid autopsy myocardial tissue, we pinpointed specific pathways and transcripts indicative of heightened inflammatory profiles in CAV lesions. Moreover, we identified protein and transcriptomic signatures distinguishing CAV lesions exhibiting low and high neointimal lesions. AOIs with low neointima showed increased markers for activated inflammatory infiltrates, endothelial cell activation transcripts, and gene modules involved in metalloproteinase activation and TP53 regulation of caspases. Inflammatory and apoptotic proteins correlated with inflammatory modules in low neointima AOIs. High neointima AOIs exhibited elevated TGFß-regulated transcripts and modules enriched for platelet activation/aggregation. Proteins associated with growth factors/survival correlated with modules enriched for proliferation/repair in high neointima AOIs. Our findings reveal novel insight into immunological mechanisms mediating CAV pathogenesis.

Extent of Surgery for Medullary Thyroid Cancer and Prevalence of Occult Contralateral Foci.

Importance: Standard treatment for patients with medullary thyroid cancer (MTC) consists of total thyroidectomy with central neck dissection, but the rationale for bilateral surgery in patients with unilateral disease on ultrasonography remains unclear. Objective: To determine the presence of occult contralateral disease (lesions not seen on preoperative ultrasonography) in patients with MTC as a rationale for total thyroidectomy. Design, Setting, and Participants: This multi-institutional, retrospective cohort study was conducted from September 1998 to April 2022 in academic medical centers and included patients with MTC who underwent thyroidectomy with preoperative imaging. Main Outcomes and Measures: The primary end point was the prevalence of sonographically occult foci of MTC in the contralateral lobe among patients with sporadic MTC. Results: The cohort comprised 176 patients with a median age at diagnosis of 55 years (range, 2-87 years), 69 (57.6%) of whom were female. Genetic testing was performed in 109 patients (61.9%), 48 (27.5%) of whom carried germline RET variants. Initial surgical management consisted of total thyroidectomy (161 [91.0%]), lobectomy followed by completion thyroidectomy (7 [4.0%]), and lobectomy alone (8 [4.5%]). Central and lateral neck dissections were performed as part of initial therapy for 146 patients (83.1%). In the entire cohort of 176 patients, 46 (26.0%) had contralateral foci disease and 9 (5.1%) had occult contralateral foci that were not identified on preoperative ultrasonography. Among 109 patients who underwent genetic testing, 38 (34.9%) had contralateral disease, 8 (7.3%) of whom had occult contralateral disease not seen on preoperative ultrasonography. Patients with sporadic MTC experienced a 95.7% reduction in the odds of having a focus of MTC in the contralateral lobe compared with patients with a germline RET variant (odds ratio, 0.043; 95% CI, 0.013-0.123). When adjusting for age, sex, tumor size, and lymph node involvement, the odds ratio of having contralateral MTC in patients with sporadic disease was 0.034 (95% CI, 0.007-0.116). Among patients who underwent lobectomy alone with postoperative calcitonin levels, 5 of 12 (41.7%) achieved undetectable calcitonin levels (<2.0 pg/mL; to convert to pmol/L, multiply by 0.292). Conclusions and Relevance: The results of this cohort study suggest that a staged approach involving initial thyroid lobectomy could be considered in patients with sporadic MTC and no contralateral ultrasonography findings, with no further surgery if calcitonin levels became undetectable. Further work using prospective randomized clinical trials to evaluate lobectomy as a biochemical cure in patients presenting with unilateral disease is warranted.

Assessing the role of phosphorylated S6 ribosomal protein in the pathological diagnosis of pulmonary antibody-mediated rejection.

BACKGROUND: Pulmonary antibody-mediated rejection is still a challenging diagnosis as C4d immunostaining has poor sensitivity. Previous studies have indicated that the phosphorylated S6 ribosomal protein, a component of the mammalian target of rapamycin (mTOR) pathway, is correlated with de novo donor-specific antibodies in lung transplantation. The objective of this study was to evaluate the phosphorylation of S6 ribosomal protein as a surrogate for antibody-mediated rejection diagnosis in lung transplant patients. METHODS: This multicentre retrospective study analyzed transbronchial biopsies from 216 lung transplanted patients, 114 with antibody-mediated rejection and 102 without (19 with acute cellular rejection, 17 with ischemia/reperfusion injury, 18 with infection, and 48 without post-transplant complications). Immunohistochemistry was used to quantify phosphorylated S6 ribosomal protein expression in macrophages, endothelium, epithelium, and inter-pathologist agreement was assessed. RESULTS: Median phosphorylated S6 ribosomal protein expression values were higher in antibody-mediated rejection cases than in controls for all cell components, with the highest sensitivity in macrophages (0.9) and the highest specificity in endothelial expression (0.8). The difference was mainly significant in macrophages compared to other post-lung transplantation complications. Inter-pathologist agreement was moderate for macrophages and endothelium, with higher agreement when phosphorylated S6 ribosomal protein expression was dichotomized into positive/negative. The inclusion of phosphorylated S6 ribosomal protein in the diagnostic algorithm could have increased antibody-mediated rejection certainty levels by 25%. CONCLUSIONS: The study supports the role of the mTOR pathway in antibody-mediated rejection-related graft injury and suggests that tissue phosphorylation of S6 ribosomal protein could be a useful surrogate for a more accurate pathological diagnosis of lung antibody-mediated rejection.

Severe Acute Respiratory Syndrome Coronavirus 2 Infection Alters Mediators of Lung Tissue Remodeling In Vitro and In Vivo.

BACKGROUND: Altered mediators of airway tissue remodeling such as matrix metalloproteinases (MMPs) in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may contribute to morbidity in coronavirus disease 2019 (COVID-19); however, the differential impact of SARS-CoV-2 variants of concern (VOCs) on MMPs is unknown. METHODS: Using both in vitro human airway cell culture model and in vivo transgenic mouse model of SARS-CoV-2 infection, we studied the differential effect of SARS-CoV-2 VOCs on expression of key MMPs and inflammatory mediators in airway cells and tissues. RESULTS: The most consistent findings with all SARS-CoV-2 variants in infected compared to uninfected human bronchial epithelial cell air-liquid interface cultures were the SARS-CoV-2-induced increases in MMP-12 and tissue inhibitor of MMPs. Infection with both SARS-CoV-2 wild type and SARS-CoV-2 Delta variant over 3 days postinfection (dpi) and with Beta variant over 7 dpi increased lung tissue levels of MMP-9 compared to uninfected mice. Overall, SARS-CoV-2 variants had differential dose-dependent impact on secretion of MMP-1, MMP-2, MMP-9, and MMP-12 that varied at the protein versus the gene level and in the early noninflammatory compared to late inflammatory phase of infection. CONCLUSIONS: We provide novel mechanistic insight that the differential impact of SARS-CoV-2 variants on severity of COVID-19 may partially be attributed to unique changes in MMPs.

Consensus statement on the processing, interpretation and reporting of temporal artery biopsy for arteritis.

Giant cell arteritis (GCA) is the most common systemic vasculitis in adults in Europe and North America, typically involving the extra-cranial branches of the carotid arteries and the thoracic aorta. Despite advances in noninvasive imaging, temporal artery biopsy (TAB) remains the gold standard for establishing a GCA diagnosis. The processing of TAB depends largely on individual institutional protocol, and the interpretation and reporting practices vary among pathologists. To address this lack of uniformity, the Society for Cardiovascular Pathology formed a committee tasked with establishing consensus guidelines for the processing, interpretation, and reporting of TAB specimens, based on the existing literature. This consensus statement includes a discussion of the differential diagnoses including other forms of arteritis and noninflammatory changes of the temporal artery.

Whole-Exome Sequencing Identifies Homozygote Nonsense Variants in LMOD2 Gene Causing Infantile Dilated Cardiomyopathy.

As an essential component of the sarcomere, actin thin filament stems from the Z-disk extend toward the middle of the sarcomere and overlaps with myosin thick filaments. Elongation of the cardiac thin filament is essential for normal sarcomere maturation and heart function. This process is regulated by the actin-binding proteins Leiomodins (LMODs), among which LMOD2 has recently been identified as a key regulator of thin filament elongation to reach a mature length. Few reports have implicated homozygous loss of function variants of LMOD2 in neonatal dilated cardiomyopathy (DCM) associated with thin filament shortening. We present the fifth case of DCM due to biallelic variants in the LMOD2 gene and the second case with the c.1193G>A (p.W398*) nonsense variant identified by whole-exome sequencing. The proband is a 4-month male infant of Hispanic descent with advanced heart failure. Consistent with previous reports, a myocardial biopsy exhibited remarkably short thin filaments. However, compared to other cases of identical or similar biallelic variants, the patient presented here has an unusually late onset of cardiomyopathy during infancy. Herein, we present the phenotypic and histological features of this variant, confirm the pathogenic impact on protein expression and sarcomere structure, and discuss the current knowledge of LMOD2-related cardiomyopathy.

Light-field tomographic fluorescence lifetime imaging microscopy.

Fluorescence lifetime imaging microscopy (FLIM) is a powerful imaging technique that enables the visualization of biological samples at the molecular level by measuring the fluorescence decay rate of fluorescent probes. This provides critical information about molecular interactions, environmental changes, and localization within biological systems. However, creating high-resolution lifetime maps using conventional FLIM systems can be challenging, as it often requires extensive scanning that can significantly lengthen acquisition times. This issue is further compounded in three-dimensional (3D) imaging because it demands additional scanning along the depth axis. To tackle this challenge, we developed a novel computational imaging technique called light field tomographic FLIM (LIFT-FLIM). Our approach allows for the acquisition of volumetric fluorescence lifetime images in a highly data-efficient manner, significantly reducing the number of scanning steps required compared to conventional point-scanning or line-scanning FLIM imagers. Moreover, LIFT-FLIM enables the measurement of high-dimensional data using low-dimensional detectors, which are typically low-cost and feature a higher temporal bandwidth. We demonstrated LIFT-FLIM using a linear single-photon avalanche diode array on various biological systems, showcasing unparalleled single-photon detection sensitivity. Additionally, we expanded the functionality of our method to spectral FLIM and demonstrated its application in high-content multiplexed imaging of lung organoids. LIFT-FLIM has the potential to open up new avenues in both basic and translational biomedical research.

COP9 Signalosome Promotes Neointimal Hyperplasia via Deneddylation and CSN5-Mediated Nuclear Export.

BACKGROUND: Neointimal hyperplasia (NH) is a common pathological response to vascular injury and mediated primarily by vascular smooth muscle cell (VSMC) migration and proliferation. The COP9 signalosome (CSN) is formed by 8 canonical subunits (CSN1 through CSN8) with its deneddylation activity residing in CSN5. Each or some of CSN subunits may have deneddylation-independent function. Despite strong evidence linking the CSN to cell cycle regulation in cancer cells, the role of the CSN in vascular biology remains obscure. METHODS: Neointimal CSN5 expression in the lung tissue of pulmonary hypertension (PAH) patients was assessed with immunohistochemistry. Adult mice with smooth muscle cell-restricted CSN5 knockout (CSN5-SMKO) or CSN8 hypomorphism (CSN8-hypo) and cultured mouse VSMCs were studied to determine the role and governing mechanisms of the CSN in NH. NH was induced by ligation of the left common carotid artery (LCCA) and PDGF-BB stimulation was used to mimic the vascular injury in cell cultures. RESULTS: Remarkably higher CSN5 levels were detected in the neointimal VSMCs of the pulmonary arteries of human PAH. LCCA ligation induced NH and significantly increased the mRNA and protein levels of CSN subunits in the LCCA wall of adult wild type mice. CSN5-SMKO impaired Cullin deneddylation and the nuclear export of p27 in vessel walls and markedly inhibited VSMC proliferation in mice. On the contrary, CSN8-hypo significantly exacerbated NH and VSMC proliferation in vivo and in cellulo . Cytoplasmic CSN5 mini-complexes and the nuclear export of p27 were significantly increased in CSN8-hypo mouse vessels and cultured CSN8-hypo VSMCs. Nuclear export inhibition with leptomycin attenuated the PDGF-BB-induced increases in VSMC proliferation in both CSN8-hypo and control VSMCs. Further, genetically disabling CSN5 nuclear export but not disabling CSN5 deneddylase activity suppressed the hyperproliferation and restored p27 nuclear localization in CSN8 hypomorphic VSMCs. Interestingly, CSN deneddylase inhibition by CSN5i-3 did not alter the hyperproliferation of cultured CSN8-hypo VSMCs but suppressed wild type VSMC proliferation in cellulo and in vivo and blocked neointimal formation in wild type mice. CONCLUSION: The CSN promotes VSMC proliferation and NH in injured vessels through deneddylation activity and CSN5-mediated nuclear export.

Accelerated Cardiac Allograft Vasculopathy in an Orthotopic Heart Transplant Recipient with Prior COVID-19.

BACKGROUND Cardiac allograft vasculopathy (CAV) is a post-orthotopic heart transplant (OHT) complication driven by intimal smooth muscle proliferation and immune hyperactivity to donor heart tissue. Accelerated CAV leads to allograft failure within 1 year after receiving a normal angiogram result. Viruses can contribute to CAV development, but CAV after SARS-CoV-2 infection has not been reported to date. CASE REPORT A 48-year-old man, 5 years after OHT for non-ischemic cardiomyopathy, was admitted to the Cardiac Care Unit with 3 days of abdominal pain, dyspnea, and palpitations. His medical history included hyperlipidemia and insulin-dependent diabetes. He was compliant with all medications. Two months prior, he had a mild COVID-19 case. An echocardiogram and coronary angiogram 6 and 9 months prior, respectively, were unremarkable. Right and left heart catheterization demonstrated increased filling pressures, a cardiac index of 1.7 L/ml/m², and diffuse vasculopathy most severe in the LAD artery. Flow could not be restored despite repeated ballooning and intra-catheter adenosine. Empiric ionotropic support, daily high-dose methylprednisolone, and plasmapheresis were started. A few days later, the patient had cardiac arrest requiring venoarterial extracorporeal membranous oxygenation. Given CAV's irreversibility, re-transplantation was considered, but the patient had an episode of large-volume hemoptysis and remained clinically unstable for transplant. The patient died while on palliative care. CONCLUSIONS Our patient developed accelerated CAV 2 months after having COVID-19. While CAV has known associations with certain viruses, its incidence after SARS-CoV-2 infection is unknown. Further research is needed to determine if prior SARS-CoV-2 infection is a risk factor for development of CAV in OHT recipients.

Commentary on why implementing and standardizing histologic diagnosis of myocarditis is crucial for the clinical setting and patient care.

Histological examination of endomyocardial biopsy or myocardium at autopsy is key to the diagnosis of myocarditis. Among pathologists there is currently extensive variability in routine practice and criteria used to define, diagnose, and report myocarditis as well as to achieve consensus on cases. Two manuscripts emphasizing the need to standardize and implement histopathological diagnostic criteria for myocarditis are reviewed.

Hypertrophic and fibrotic human PKD hearts are associated with macrophage infiltration and abnormal TGF-ß1 signaling.

Autosomal dominant polycystic kidney disease (PKD) is a hereditary kidney disorder which can affect cardiovascular system. Cardiac hypertrophy and cardiomyopathy in PKD have been reported by echocardiography analyses, but histopathology analyses of human PKD hearts have never been examined. The current studies evaluated human heart tissues from five subjects without PKD (non-PKD) and five subjects with PKD. Our histopathology data of human PKD hearts showed an increased extracellular matrix associated with cardiac hypertrophy and fibrosis. Hypertrophy- and fibrosis-associated pathways involving abnormal cardiac structure were next analyzed. We found that human PKD myocardium was infiltrated by inflammatory macrophage M1 and M2; expression of transforming growth factor (TGF-ß1) and its receptor were upregulated with overexpression of pSmad3 and ß-catenin. Because patients with PKD have an abnormal kidney function that could potentially affect heart structure, we used a heart-specific PKD mouse model to validate that cardiac hypertrophy and fibrosis were independent from polycystic kidney. In summary, our data show that hearts from human PKD were characterized by hypertrophy, interstitial fibrosis, perivascular fibrosis, and conduction system fibrosis with upregulated TGF-ß1 and its receptor. We suggest that such structural abnormalities may predispose to systolic and diastolic cardiac dysfunction in the PKD myocardium.

Matrix metalloproteinase-7 is increased in lung bases but not apices in idiopathic pulmonary fibrosis.

Introduction: Idiopathic pulmonary fibrosis (IPF) is a progressively fibrotic lung condition with poor prognosis. Matrix metalloproteinase-7 (MMP7) is a protein secreted by epithelial cells in IPF lungs. It is not known if MMP7 expression correlates with fibrotic changes in lung tissue. Methods: Tissue samples from lung apices and bases were obtained from 20 IPF patients and 14 non-diseased control (NDC) donors. In formalin-fixed paraffin-embedded sections, histological assessment of fibrosis was performed; overall MMP7 positivity was assessed by immunohistochemistry and MMP7+ cells were quantified using multiplex immunohistochemistry. Protein expression of MMP7 in whole lung lysates was quantified by Western blotting. Bulk tissue transcriptomic profiles of 101 samples were analysed using RNA sequencing technologies. Results: Lung tissue from IPF bases was more fibrotic than in apices. MMP7 protein is elevated in IPF lung base tissue. In IPF whole lung lysates, MMP7 protein levels are increased compared to NDC donors and was increased in IPF lung bases compared to apices. MMP7 protein levels correlated with MMP7 gene expression levels in lung tissue. MMP7 transcript levels were increased in IPF base compared to NDC base lung tissue and increased in IPF base tissue compared to IPF apex tissue. Conclusions: Our cross-sectional study suggests that lung epithelial MMP7 expression increases as the tissue becomes more fibrotic and identifies a potentially nonepithelial or immune-cell source. Mechanisms of disease progression in IPF are still unclear, and our study suggests aberrant MMP7 production may be a histological starting point of lung tissue fibrosis.

Predictors of Invasiveness in Adenocarcinoma of Lung with Lepidic Growth Pattern.

Lung adenocarcinoma with lepidic growth pattern (LPA) is characterized by tumor cell proliferation along intact alveolar walls, and further classified as adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA) and invasive lepidic predominant adenocarcinoma (iLPA). Accurate diagnosis of lepidic lesions is critical for appropriate prognostication and management as five-year survival in patients with iLPA is lower than in those with AIS and MIA. We aimed to evaluate the accuracy of CT-guided core needle lung biopsy classifying LPA lesions and identify clinical and radiologic predictors of invasive disease in biopsied lesions. Thirty-four cases of adenocarcinoma with non-invasive lepidic growth pattern on core biopsy pathology that subsequently were resected between 2011 and 2018 were identified. Invasive LPA vs. non-invasive LPA (AIS or MIA) was defined based on explant pathology. Histopathology of core biopsy and resected tumor specimens was compared for concordance, and clinical, radiologic and pathologic variables were analyzed to assess for correlation with invasive disease. The majority of explanted tumors (70.6%) revealed invasive disease. Asian race (p = 0.03), history of extrathoracic malignancy (p = 0.02) and absence of smoking history (p = 0.03) were associated with invasive disease. CT-measured tumor size was not associated with invasiveness (p = 0.15). CT appearance of density (p = 0.61), shape (p = 0.78), and margin (p = 0.24) did not demonstrate a significant difference between the two subgroups. Invasiveness of tumors with lepidic growth patterns can be underestimated on transthoracic core needle biopsies. Asian race, absence of smoking, and history of extrathoracic malignancy were associated with invasive disease.

Plasma CXCL9 and CXCL10 at allograft injury predict chronic lung allograft dysfunction.

Histopathologic lung allograft injuries are putative harbingers for chronic lung allograft dysfunction (CLAD). However, the mechanisms responsible are not well understood. CXCL9 and CXCL10 are potent chemoattractants of mononuclear cells and potential propagators of allograft injury. We hypothesized that these chemokines would be quantifiable in plasma, and would associate with subsequent CLAD development. In this prospective multicenter study, we evaluated 721 plasma samples for CXCL9/CXCL10 levels from 184 participants at the time of transbronchial biopsies during their first-year post-transplantation. We determined the association between plasma chemokines, histopathologic injury, and CLAD risk using Cox proportional hazards models. We also evaluated CXCL9/CXCL10 levels in bronchoalveolar lavage (BAL) fluid and compared plasma to BAL with respect to CLAD risk. Plasma CXCL9/CXCL10 levels were elevated during the injury patterns associated with CLAD, acute rejection, and acute lung injury, with a dose-response relationship between chemokine levels and CLAD risk. Importantly, there were strong interactions between injury and plasma CXCL9/CXCL10, where histopathologic injury associated with CLAD only in the presence of elevated plasma chemokines. We observed similar associations and interactions with BAL CXCL9/CXCL10 levels. Elevated plasma CXCL9/CXCL10 during allograft injury may contribute to CLAD pathogenesis and has potential as a minimally invasive immune monitoring biomarker.

Mitoquinone mesylate targets SARS-CoV-2 infection in preclinical models.

To date, there is no effective oral antiviral against SARS-CoV-2 that is also anti-inflammatory. Herein, we show that the mitochondrial antioxidant mitoquinone/mitoquinol mesylate (Mito-MES), a dietary supplement, has potent antiviral activity against SARS-CoV-2 and its variants of concern in vitro and in vivo . Mito-MES had nanomolar in vitro antiviral potency against the Beta and Delta SARS-CoV-2 variants as well as the murine hepatitis virus (MHV-A59). Mito-MES given in SARS-CoV-2 infected K18-hACE2 mice through oral gavage reduced viral titer by nearly 4 log units relative to the vehicle group. We found in vitro that the antiviral effect of Mito-MES is attributable to its hydrophobic dTPP+ moiety and its combined effects scavenging reactive oxygen species (ROS), activating Nrf2 and increasing the host defense proteins TOM70 and MX1. Mito-MES was efficacious reducing increase in cleaved caspase-3 and inflammation induced by SARS-CoV2 infection both in lung epithelial cells and a transgenic mouse model of COVID-19. Mito-MES reduced production of IL-6 by SARS-CoV-2 infected epithelial cells through its antioxidant properties (Nrf2 agonist, coenzyme Q10 moiety) and the dTPP moiety. Given established safety of Mito-MES in humans, our results suggest that Mito-MES may represent a rapidly applicable therapeutic strategy that can be added in the therapeutic arsenal against COVID-19. Its potential long-term use by humans as diet supplement could help control the SARS-CoV-2 pandemic, especially in the setting of rapidly emerging SARS-CoV-2 variants that may compromise vaccine efficacy. One-Sentence Summary: Mitoquinone/mitoquinol mesylate has potent antiviral and anti-inflammatory activity in preclinical models of SARS-CoV-2 infection.

The allograft injury marker CXCL9 determines prognosis of anti-HLA antibodies after lung transplantation.

Despite the common detection of non-donor specific anti-HLA antibodies (non-DSAs) after lung transplantation, their clinical significance remains unclear. In this retrospective single-center cohort study of 325 lung transplant recipients, we evaluated the association between donor-specific HLA antibodies (DSAs) and non-DSAs with subsequent CLAD development. DSAs were detected in 30% of recipients and were associated with increased CLAD risk, with higher HRs for both de novo and high MFI (>5000) DSAs. Non-DSAs were detected in 56% of recipients, and 85% of DSA positive tests had concurrent non-DSAs. In general, non-DSAs did not increase CLAD risk in multivariable models accounting for DSAs. However, non-DSAs in conjunction with high BAL CXCL9 levels were associated with increased CLAD risk. Multivariable proportional hazards models demonstrate the importance of the HLA antibody-CXCL9 interaction: CLAD risk increases when HLA antibodies (both DSAs and non-DSAs) are detected in conjunction with high CXCL9. Conversely, CLAD risk is not increased when HLA antibodies are detected with low CXCL9. This study supports the potential utility of BAL CXCL9 measurement as a biomarker to risk stratify HLA antibodies for future CLAD. The ability to discriminate between high versus low-risk HLA antibodies may improve management by allowing for guided treatment decisions.

Recessive ciliopathy mutations in primary endocardial fibroelastosis: a rare neonatal cardiomyopathy in a case of Alstrom syndrome.

Among neonatal cardiomyopathies, primary endocardial fibroelastosis (pEFE) remains a mysterious disease of the endomyocardium that is poorly genetically characterized, affecting 1/5000 live births and accounting for 25% of the entire pediatric dilated cardiomyopathy (DCM) with a devastating course and grave prognosis. To investigate the potential genetic contribution to pEFE, we performed integrative genomic analysis, using whole exome sequencing (WES) and RNA-seq in a female infant with confirmed pathological diagnosis of pEFE. Within regions of homozygosity in the proband genome, WES analysis revealed novel parent-transmitted homozygous mutations affecting three genes with known roles in cilia assembly or function. Among them, a novel homozygous variant [c.1943delA] of uncertain significance in ALMS1 was prioritized for functional genomic and mechanistic analysis. Loss of function mutations of ALMS1 have been implicated in Alstrom syndrome (AS) [OMIM 203800], a rare recessive ciliopathy that has been associated with cardiomyopathy. The variant of interest results in a frameshift introducing a premature stop codon. RNA-seq of the proband's dermal fibroblasts confirmed the impact of the novel ALMS1 variant on RNA-seq reads and revealed dysregulated cellular signaling and function, including the induction of epithelial mesenchymal transition (EMT) and activation of TGFß signaling. ALMS1 loss enhanced cellular migration in patient fibroblasts as well as neonatal cardiac fibroblasts, while ALMS1-depleted cardiomyocytes exhibited enhanced proliferation activity. Herein, we present the unique pathological features of pEFE compared to DCM and utilize integrated genomic analysis to elucidate the molecular impact of a novel mutation in ALMS1 gene in an AS case. Our report provides insights into pEFE etiology and suggests, for the first time to our knowledge, ciliopathy as a potential underlying mechanism for this poorly understood and incurable form of neonatal cardiomyopathy. KEY MESSAGE: Primary endocardial fibroelastosis (pEFE) is a rare form of neonatal cardiomyopathy that occurs in 1/5000 live births with significant consequences but unknown etiology. Integrated genomics analysis (whole exome sequencing and RNA sequencing) elucidates novel genetic contribution to pEFE etiology. In this case, the cardiac manifestation in Alstrom syndrome is pEFE. To our knowledge, this report provides the first evidence linking ciliopathy to pEFE etiology. Infants with pEFE should be examined for syndromic features of Alstrom syndrome. Our findings lead to a better understanding of the molecular mechanisms of pEFE, paving the way to potential diagnostic and therapeutic applications.