Introduction: Loss of tissue elasticity and senescent-cell accumulation are two hallmarks of ageing. Both structural damage to lung elastin fibres (with decreased elasticity that impairs alveolar function) and exaggerated lung-cell senescence (inducing aberrant cytokine and metalloprotease secretion and impairing lung-tissue renewal) are key pathogenic factors in lung emphysema and COPD. However, whether lung elasticity, elastin expression, and senescence are linked remains unknown. Here, we investigated whether decreased elastin levels resulted in lung-cell senescence and whether this senescence promoted lung alterations. Methods: We combined studies of human-lung tissues and cells from patients with pulmonary emphysema (PE) and controls and studies of mice with elastase-induced PE or deletion of one elastin allele (ELN+/-). We monitored p16 activation by luminescence imaging in p16-luciferase (p16LUC/+) knock-in mice. Senescent cells (SC) clearance was obtained by a suicide gene (p16 promoter-driven killer gene construct in p16-ATTAC mice), senolytic drugs (ABT263 and cell-permeable FOXO4-p53 interfering peptide [FOXO4-DRI]); and p16 inactivation in p16LUC/LUC mice. Results: Treatment of healthy human cells with elastin siRNA induced senescence, as assessed by SA-β-Gal staining, p16 and p21 expression levels, and replicative capacity. This effect was attenuated when cells were seeded on an elastin-rich matrix before siRNA treatment. Similarly, cultured lung fibroblasts from patienst with COPD and from Eln+/− mice exhibited a senescence phenotype which was attenuated when cells were seeded on an elastin-rich matrix or after tropelastin genes transduction. Elastase-treated mice and Eln+/- mice showed increased markers of pulmonary senescence as well as accumulation of p16-expressing cells and development of PE. In p16-ATTAC mice activation of the ATTAC transgene prevented elastase-induced pulmonary functional and structural alterations. In Eln+/- mice, treatment with the senolytic drugs ABT263 or Foxo4 DR1 for 3 weeks partially reversed PE as assessed mechanically (pulmonary compliance, elastance) and histologically and increased lung elastin levels and pulmonary repair processes. Conclusion: PE is characterized by physical destruction of parenchymal elastic fibres and markedly increased cell senescence. Our data indicate close links between elastin dysregulation, cell senescence, and PE. Targeting senescent cells is a new therapeutic strategy to induce pulmonary repair and stimulate elastogenesis in PE.

Influenza A virus (IAV) infection causes acute and long-term lung damage. Here, we used immunostaining, genetic, and pharmacological approaches to determine whether IAV-induced cellular senescence causes prolonged alterations in lungs. Mice infected with a sublethal dose of H1N1p2009 exhibited cellular senescence, as evidenced by increased pulmonary expression of p16, p21, β-galactosidase and the DNA damage marker gamma-H2A.X. Cellular senescence began 4 days post-infection (dpi) in the bronchial epithelium, then spread to the lung parenchyma by 7 and 28 dpi (long after viral clearance), and then declined by 90 dpi. At 28 dpi, the lungs showed severe remodeling with structural bronchial and alveolar lesions, abrasion of the airway epithelium, and pulmonary emphysema and fibrotic lesions that persisted up to 90 dpi. In mice and nonhuman primates, persistence of senescent cells in the bronchial wall on 28 dpi was associated with abrasion of the airway epithelium. In p16-ATTAC mice, depletion of p16-expressing cells with AP20187 reduced pulmonary emphysema and fibrosis and led to complete recovery of the airway epithelium at 28 dpi, indicating a marked acceleration of the epithelial repair process. Treatment with the senolytic drug ABT-263 also accelerated epithelial repair without affecting pulmonary fibrosis or emphysema. These positive effects occurred independently of viral clearance and lung inflammation at 7 dpi. Finally, AP20187 treatment of p16-ATTAC mice at 15 dpi led to complete recovery of the airway epithelium at 28 dpi. Thus, virus-induced senescent cells contribute to the pulmonary sequelae of influenza; targeting senescent cells may represent a new preventive therapeutic option.

BACKGROUND:Pulmonary hypertension (PH) is a life-threatening and progressive yet incurable disease. The hallmarks of PH comprise (1) sustained contraction and (2) excessive proliferation of pulmonary arterial smooth muscle cells (PASMCs). A major stimulus to which PASMCs are exposed during PH development is altered mechanical stress, originating from increased blood pressure, changes in blood flow velocity, and a progressive stiffening of pulmonary arteries. Mechanosensitive ion channels, including Piezo1 (Piezo-type mechanosensitive ion channel component-1), perceive such mechanical stimuli and translate them into a variety of cellular responses, including contractility or proliferation. Thus, the objective of the present study was to elucidate the specific role of Piezo1 in PASMCs for PH development and progression. METHODS:The cell-type specific function of Piezo1 in PH was assessed in (1) PASMCs and lung tissues from patients with PH and (2) 2 mouse strains characterized by smooth muscle cell-specific, conditional Piezo1 knockout. Taking advantage of these strains, the smooth muscle cell-specific role of Piezo1 in PH development and progression was assessed in isolated, perfused, and ventilated mouse lungs, wire myography, and proliferation assays. Finally, in vivo function of smooth muscle cell-specific Piezo1 knockout was evaluated upon induction of chronic hypoxia-induced PH in these mice with insights into pulmonary vascular cell senescence. RESULTS:Compared with healthy controls, PASMCs from patients with PH featured an elevated Piezo1 expression and increased proliferative phenotype. Smooth muscle cell-specific Piezo1 deletion, as confirmed via quantitative real-time polymerase chain reaction and patch clamp recordings, prevented the hypoxia-induced increase in PASMC proliferation in mice. Moreover, Piezo1 knockout reduced hypoxic pulmonary vasoconstriction in isolated, perfused, and ventilated mouse lungs, endothelial-denuded pulmonary arteries, and hemodynamic measurements in vivo. Consequently, Piezo1-deficient mice were considerably protected against chronic hypoxia-induced PH development with ameliorated right heart hypertrophy and improved hemodynamic function. In addition, distal pulmonary capillaries were preserved in the Piezo1-knockout mice, associated with a lower number of senescent endothelial cells. CONCLUSIONS:This study provides evidence that Piezo1 expressed in PASMCs is critically involved in the pathogenesis of PH by controlling pulmonary vascular tone, arterial remodeling, and associated lung capillary rarefaction due to endothelial cell senescence.

Introduction Pulmonary hypertension (PH) is a life-threatening and progressive, but yet incurable disease. The hallmarks of PH comprise sustained contraction and excessive proliferation of pulmonary arterial smooth muscle cells (PASMCs). A major stimulus to which PASMCs are exposed during PH development is altered mechanical stress. Mechanosensitive ion channels, such as Piezo1, perceive such mechanical stimuli and translate them into various cellular responses. Thus, the objective of the present study was to elucidate the specific role of Piezo1 in PASMCs for PH-development and progression. Methods Taking advantage of PASMCs from idiopathic pulmonary arterial hypertension (IPAH)-patients and two mouse strains characterized by SMC-specific Piezo1 knock-out, we assessed the SMC-specific role of Piezo1 in PH-development and progression via experiments in isolated, perfused and ventilated mouse lungs, wire myography and proliferation assays. In vivo function of SMC-specific Piezo1 knockout was evaluated upon induction of chronic hypoxia-induced PH (CHPH) with insights into pulmonary vascular cell senescence. Results Compared to healthy controls, PASMCs from PH-patients featured an elevated Piezo1-expression and increased proliferative phenotype. SMC-specific Piezo1-deletion, as confirmed via qPCR and patch clamp recordings, prevented the hypoxia-induced increase in PASMC-proliferation in mice. Moreover, Piezo1-knockout reduced hypoxic pulmonary vasoconstriction (HPV) in isolated, perfused and ventilated mouse lungs, endothelial-denuded pulmonary arteries and hemodynamic measurements in vivo. Consequently, Piezo1-deficient mice were considerably protected against CHPH-development with ameliorated right heart hypertrophy and improved hemodynamic function. In addition, distal pulmonary capillaries were preserved in the Piezo1-knockout mice, associated with a lower number of senescent endothelial cells. Conclusions This study provides evidence that Piezo1 expressed in PASMCs is critically involved in the pathogenesis of PH – by controlling pulmonary vascular tone, and arterial remodeling, and associated lung capillary rarefaction due to endothelial cell senescence.

IntroductionLe vieillissement vasculaire entraîne une raréfaction des microvaisseaux. Le mécanisme proposé est une insuffisance de signalisation du facteur de croissance endothélial vasculaire (VEGF) dont l’action est perturbée par une production accrue d’une forme soluble de son récepteur VEGFR1 (sVEGFR1) qui l’empêche de se fixer à son récepteur actif, le VEGFR1 exprimé par les CEs. Les CEs des microvaisseaux pulmonaires (PCEs) sont nécessaires à la fonction des poumons et nécessitent le signal de survie du VEGF, en l’absence duquel elles peuvent rentrer en sénescence, caractérisée par un arrêt de la division cellulaire et la libération de facteurs nocifs pour les poumons. Nous avons montré une accumulation de PCEs sénescentes au cours de l’hypertension (HTP) et de l’emphysème pulmonaires.MéthodeÉvaluer l’insuffisance de signalisation du VEGF dans la sénescence des PCEs liée à deux pathologies, l’hypertension (HTP) et l’emphysème pulmonaires.RésultatsLes poumons des souris âgées par rapport aux jeunes souris ont une densité capillaire plus faible se manifestant par une diminution du nombre de PCEs identifiées en immunohistochimie par marquage de l’ICAM1 ou de l’isolectine B4. Le traitement des souris par l’inhibiteur du récepteur du VEGF Sugen amplifie ces effets et augmente le nombre de PCEs sénescentes marquées p16, en diminuant le réseau capillaire pulmonaire, en détériorant l’hémodynamique pulmonaire et en induisant de l’emphysème. L’expression pulmonaire de sVEGFR1 chez les souris développant une HTP hypoxique est augmentée et aggravée par le Sugen, de même que l’expression pulmonaire de deux facteurs modulant l’épissage alternatif du VEGFR1 et la formation de sVEGFR1, le domaine Jumonji contenant la protéine 6 (Jmjd6) et le TNFSF15. Nous montrons in vitro qu’un traitement par le sVEGFR1 de PCEs en culture issues de patients (étude Costemcells) entraîne une augmentation de la sénescence cellulaire. Pour contrer la forte susceptibilité des PCEs à la sénescence dans l’HTP et l’emphysème, nous avons généré un nouveau modèle murin qui surexprime le VEGF selon un système Tet On inductible et spécifique au tissu. Ces souris sont en cours d’étude, croisées avec des souris exprimant la Cre-recombinase dans le foie (souris Alb-Cre), afin d’assurer un apport contrôlé de VEGF du foie vers les poumons.ConclusionL’augmentation du sVEGFR1 circulant au cours du vieillissement et des pathologies pulmonaires tels que l’HTP et l’emphysème pourrait être responsable de la sénescence des PCEs. Contrecarrer l’insuffisance de signalisation du VEGF devrait permettre de réduire la sévérité de ces pathologies.

IntroductionCellular senescence – defined as a stable cell-cycle arrest combined with stereotyped phenotypic changes – plays a causal role in a variety of aged-associated lung diseases. Previous work by our groups and others has shown that cellular senescence contributes to the pathobiology of both lung emphysema and lung fibrosis. However, it remains a conundrum on how these different pathological entities share a common pathogenic mechanism, i.e. lung senescent cell accumulation. The mTOR (mechanistic target of rapamycin) pathway has been validated as o,ne of a cell-senescence inducer. We reasoned here that activation of mTORC1 could either promote lung emphysema or fibrosis depending on the specific lung cell types undergoing senescence.MethodsWe generated mice with conditional deletion of the tuberous sclerosis complex heterodimer TSC1 (a negative mTORC1 regulator) in selected lung cells including fibroblast and SMCs (SM22-TSC1–/–mice), endothelial cells (P-ECs; PDGF-TSC1–/–mice), and alveolar epithelial cells (AECs; SPC-TSC1–/–mice) Mice with conditional and cell-specific TSC1 deletion were generated using the cre-lox strategy.ResultsCompared with controls, SM22-TSC1–/–mice developed lung fibrosis as assessed by the Ashcroft score but without lung emphysema as assessed by the absence of changes in the mean linear intercept. In contrast, PDGF-TSC1–/–mice developed lung emphysema with no significant associated lung fibrosis whereas SPC-TSC1–/–mice developed both lung emphysema and lung fibrosis, although to a lower extent than SM22TSC1 mice. This occurred together with an increase of the lung protein levels of the senescence markers p16 and p21as well as of the DNA damage marker gH2AX in the three mice strains, with p16 being higher in SM22-TSC1–/–mice than in the two other mutant mice. By the phenotypes of the mutant mice, the fibrosis markers Col1A, PAI1, and vimentin Col3, were increased in both SM22 and SPC-TSC1–/–mice whereas Col3 and pSmad3 were increased only in SM22-TSC1–/–mice. As expected TSC1 deletion in targeted cells leads to higher lung levels of p-AktSer-473, p-GSK-3, p-S6K, and p–4E-BP1 after 3 months. To question whether mice with TSC1 deletion in selected cells developed lung alterations due to the induction of cell senescence, we treated the three mutant mouse strains with the senolytic compound ABT263 (50mg/kg/day) 3 times a week during the 3 weeks following tamoxifen treatment. Treatment with ABT263 efficiently reduced the phenotypic alterations in the three mouse strains.ConclusionLung mTOR activation may lead to either lung fibrosis or emphysema via senescence of selected lung cells.

IntroductionObstructive sleep apnoea (OSA) syndrome is a common sleep disorder in which recurrent apnoea and hypopnoea produce repeated episodes of hypoxemia followed by reoxygenation. We previously demonstrated that OSA was associated with telomere shortening and increased susceptibility to cell senescence [1]. The cyclin-dependent kinase inhibitor p21, the main effector of p53, is activated in response to DNA damage and telomere dysfunction but is down-regulated by certain clock genes. Sleep abnormalities also disrupt endogenous circadian clock genes, more specifically Rev-Erbα, a central transcriptional repressor of the molecular clock that downregulates p21 expression.MethodsHere we investigated the effect of chronic intermittent hypoxia (CIH), a model of OSA, on lung cell senescence induction in mice. To this end, we exposed 2-month-old c57/bl6 mice to CIH (8hours a day) for one to 21 days and harvested lungs for histological and biological analyses, the day after CIH was stopped.ResultsWe found that the rhythmicity of the canonical clock genes Rev-Erbα, Rev-Erbß and Bmal-1 was associated with a rhythmicity of lung p21 during normoxia, with opposite variations of Rev-Erbα and p21. Exposure to CIH lead to an increase in Rev-Erbα at ZT 2-4 (morning) compared to normoxia, together with a downregulation of p21, observed either after 1.2, 7, or 21 days of CIH exposure, and lasting longer than 48hours after return to normoxia. No changes were observed at later time of the day. Consistent with this, senescence markers, including p16 and SASP components, were not affected by exposure to CIH. Similar changes were observed in aged (18-month-old) mice. Bulk RNA sequencing performed 3 weeks after CIH confirmed dysregulation of circadian clock and clock-controlled genes (Dbp, Rev-Erbα, Hlf) together with an increase in several collagen transcripts. Treatment of the mice with a Rev-Erbα antagonist (SR8278), partially restored the reduction in p21 expression after one day CIH, pointing toward a causal link between changes in lung Rev-Erbα and p21 during CIH. Interestingly, mice exposed to 21 days and even to 35 days CIH did not develop lung structural alterations, potentially as a consequence of a protection afforded by p21 downregulation and protection against cell senescence. Studies are underway to assess the consequences of CIH exposure in Rev-Erbα and Bmal-1 deficient mice.ConclusionOur data indicate that CIH has a major impact on clock genes expression, which may in turn play a protective role against cell senescence.

ABSTRACTTelomerase is required for long-term cell proliferation and linked to stem cells. This is evident in the lung where short telomeres are associated with lung dysfunction. We constructed a mouse model in which the telomerase (Tert) is expressed from the p21Cdkn1apromoter. We found that this peculiar Tert expression curb age-related emphysema and pulmonary perivascular fibrosis in old mice. In old mice lungs, such Tert expression preferentially occurs in endothelial cells where it reduces the number of senescent endothelial cells. Remarkably, we report that Tert counteracts the age-related decline in capillary density. This was associated with an increased number of Cd34+ cells identified as a subclass of capillary cells with proliferative capacity. Expression of catalytically inactiveTertneither prevents the decline of capillary density in old mice nor protects against age-related emphysema and fibrosis. These findings reveal that telomerase decreases age-decline of pulmonary functions by sustaining microvasculature regeneration and outgrowth.

IntroductionPulmonary hypertension (PH) is a life-threatening and progressive, but yet incurable disease. The hallmarks of PH comprise sustained contraction and excessive proliferation of pulmonary arterial smooth muscle cells (PASMCs). A major stimulus to which PASMCs are exposed during PH-development is altered mechanical stress. Mechanosensitive ion channels, such as Piezo1, perceive such mechanical stimuli and translate them into various cellular responses. Thus, the objective of the present study was to elucidate the specific role of Piezo1 in PASMCs for PH-development and progression.MethodsTaking advantage of PASMCs from idiopathic pulmonary arterial hypertension (IPAH)-patients and two mouse strains characterized by SMC-specific Piezo1-knockout, we assessed the SMC-specific role of Piezo1 in PH-development and progression via experiments in isolated, perfused and ventilated mouse lungs, wire myography and proliferation assays. In vivo function of SMC-specific Piezo1-knockout was evaluated upon induction of chronic hypoxia-induced PH (CHPH).ResultsPiezo1 expression and proliferation was enhanced in PASMCs from IPAH-patients and mice PASMCs upon hypoxic exposure. SMC-specific Piezo1-deletion prevented the hypoxia-induced increase in proliferation. Moreover, Piezo1-knockout reduced hypoxic pulmonary vasoconstriction (HPV) in isolated, perfused and ventilated mouse lungs, pulmonary arteries and hemodynamic measurements in vivo. Consequently, Piezo1-deficient mice were significantly protected against CHPH-development with ameliorated right heart hypertrophy and improved hemodynamic function.ConclusionThis study provides evidence for Piezo1 expressed in PASMCs being critically involved in the pathogenesis of PH – most likely by controlling pulmonary vascular tone and arterial remodeling.

Cellular senescence is induced by many stresses including telomere shortening, DNA damage, oxidative, or metabolic stresses. Senescent cells are stably cell cycle arrested and they secrete many factors including cytokines and chemokines. Accumulation of senescent cells promotes many age-related alterations and diseases. In this study, we investigated the role of the pro-senescent phospholipase A2 receptor 1 (PLA2R1) in regulating some age-related alterations in old mice and in mice subjected to a Western diet, whereas aged wild-type mice displayed a decreased ability to regulate their glycemia during glucose and insulin tolerance tests, aged Pla2r1 knockout (KO) mice efficiently regulated their glycemia and displayed fewer signs of aging. Loss of Pla2r1 was also found protective against the deleterious effects of a Western diet. Moreover, these Pla2r1 KO mice were partially protected from diet-induced senescent cell accumulation, steatosis, and fibrosis. Together these results support that Pla2r1 drives several age-related alterations, especially in the liver, arising during aging or through a Western diet.

Background: Senescent cells (SCs) are involved in proliferative disorders, but their role in pulmonary hypertension remains undefined. We investigated SCs in patients with pulmonary arterial hypertension and the role of SCs in animal pulmonary hypertension models. Methods: We investigated senescence (p16, p21) and DNA damage (γ-H2AX, 53BP1) markers in patients with pulmonary arterial hypertension and murine models. We monitored p16 activation by luminescence imaging in p16-luciferase (p16LUC/+) knock-in mice. SC clearance was obtained by a suicide gene (p16 promoter–driven killer gene construct in p16-ATTAC mice), senolytic drugs (ABT263 and cell-permeable FOXO4-p53 interfering peptide [FOXO4-DRI]), and p16 inactivation in p16LUC/LUC mice. We investigated pulmonary hypertension in mice exposed to normoxia, chronic hypoxia, or hypoxia+Sugen, mice overexpressing the serotonin transporter (SM22-5-HTT+), and rats given monocrotaline. Results: Patients with pulmonary arterial hypertension compared with controls exhibited high lung p16, p21, and γ-H2AX protein levels, with abundant vascular cells costained for p16, γ-H2AX, and 53BP1. Hypoxia increased thoracic bioluminescence in p16LUC/+ mice. In wild-type mice, hypoxia increased lung levels of senescence and DNA-damage markers, senescence-associated secretory phenotype components, and p16 staining of pulmonary endothelial cells (P-ECs, 30% of lung SCs in normoxia), and pulmonary artery smooth muscle cells. SC elimination by suicide gene or ABT263 increased the right ventricular systolic pressure and hypertrophy index, increased vessel remodeling (higher dividing proliferating cell nuclear antigen–stained vascular cell counts during both normoxia and hypoxia), and markedly decreased lung P-ECs. Pulmonary hemodynamic alterations and lung P-EC loss occurred in older p16LUC/LUC mice, wild-type mice exposed to Sugen or hypoxia+Sugen, and SM22-5-HTT+ mice given either ABT263 or FOXO4-DRI, compared with relevant controls. The severity of monocrotaline-induced pulmonary hypertension in rats was decreased slightly by ABT263 for 1 week but was aggravated at 3 weeks, with loss of P-ECs. Conclusions: Elimination of senescent P-ECs by senolytic interventions may worsen pulmonary hemodynamics. These results invite consideration of the potential impact on pulmonary vessels of strategies aimed at controlling cell senescence in various contexts.

La sénescence cellulaire est un mécanisme clé dans la physiopathologie des maladies liées à l’âge. L’accumulation de cellules sénescentes dans les tissus conduit à un défaut de régénération tissulaire associé à une inflammation par la production du SASP ou « secrétome associé à la sénescence ». Limiter la sénescence cellulaire et le SASP représente un objectif thérapeutique majeur dans les maladies pulmonaires liées à l’âge. Nous avons montré une activation de la voie JAK/STAT chez les patients BPCO associée à la surexpression du récepteur à la phospholipase A2 (PLA2R1). Dans les cellules de patients, l’inhibition de la voie JAK/STAT par le ruxolitinib réduit la sénescence cellulaire et la production du SASP associés à la surexpression de PLA2R1. Chez des souris surexprimant PLA2R1 et développant un emphysème et une fibrose pulmonaire, le traitement au ruxolitinib exerce une action préventive et curative. Au vu de ces résultats, l’hypothèse est que l’inhibition pharmacologique de la voie JAK/STAT par le ruxolitinib pourrait être utilisée comme stratégie thérapeutique sénomorphique afin de limiter l’emphysème et la fibrose pulmonaires indépendamment de PLA2R1. Évaluer l’efficacité d’un traitement de 21 jours au ruxolitinib dans deux modèles murins d’emphysème et de fibrose pulmonaires induits respectivement par l’injection intratrachéale d’élastase ou de bléomycine. L’élastase dans des souris exprimant la luciférase sous le contrôle du promoteur p16 (souris p16-luciferase) induit un fort signal luminescent partiellement inhibé par le ruxolitinib. Chez les souris C57Bl6, l’augmentation de la compliance et des lésions d’emphysème pulmonaire induites par l’elastase sont diminuées par le ruxolitinib, de même que l’expression de p21, p16 et des marqueurs du SASP. Chez les souris traitées par la bléomycine, le ruxolitinib améliore la compliance et réduit la fibrose. L’inhibition de la voie JAK/STAT pourrait représenter une stratégie sénomorphique permettant de réduire les altérations pulmonaires associées à l’accumulation de cellules sénescentes pulmonaires.

Older age is an important risk factor for severe COVID-19 disease. Understanding the biological mechanisms that link aging to the pathogenesis of COVID-19 is essential for developing of therapeutic strategies. We hypothesized that cell senescence, a basic aging process that plays a pivotal role in lung diseases, is involved in the pathogenesis of COVID-19 including the development of long-lasting lung alterations. To evaluate the impact of SARS-CoV-2 infection on cell senescence, we (1) analyzed publicly available datasets of scRNA-seq performed in BALF cells from patients with moderate or severe/critical COVID-19; (2) investigated lung samples from cynomolgus macaques infected with 10 6 pfu of a SARS-CoV-2 clinical isolate. Two macaques were sacrificed at 4 days post-infection (dpi.) and two others at 30 dpi. In BALF obtained within 10 days after symptom onset, the expression of several senescence markers, i.e., CDKN2A, CDKN1A (encoding p21), uPAR, CXCL8, IGFBP3, and GDF15 was significantly increased in epithelial cells in BALF from patients with severe COVID-19, suggesting that lung-cell senescence induction was contemporary of viral detection. Next, we investigated macaques at 4 and 30 dpi, corresponding respectively to the viral load peak and to the absence of detectable viral RNA in BALF (1). Immunohistochemical analysis revealed numerous SARS-CoV-2 antigen-stained cells, also co-stained for senescence markers p16- and p21. The lungs at 30 dpi no longer contained the consolidated parenchymal areas seen at 4 dpi but showed extensive lung parenchyma remodelling, with thickening of the alveoli and pulmonary vessel walls and abundant extracellular matrix deposits as assessed by collagen staining. These lesions were accompanied with massive accumulation of p16- and p21-positive cells, mostly pneumocytes II and ECs. Of note, p16 staining of most ECs was seen in pulmonary vessels, notably those occluded by thrombosis and showing intraluminal vWF staining. Cells stained for p16 were alsostained for the DNA damage markers γ-H2AX protein and p53-binding protein [1] . Our data constitute the first evidence of temporal and topographic relations between senescent-cell accumulation and pulmonary lesions induced by SARS-CoV-2 infection.

Both shorter telomeres and schizophrenia have been associated with a decrease in life expectancy. Furthermore, several studies found a shorter telomere length (TL) in schizophrenia. Understanding whether or not telomere shortening is directly related to pathophysiology of schizophrenia or is a consequence of a cumulative exposure to chronic stress is of major importance. Comparing the TL of subjects at the very beginning of the disease (FEP) and control subjects could help to decide between these two hypotheses. The aim of the present study was to compare TL between FEP subjects (N=91) and controls (N=137). After accounting for multiple potential confounders, no significant association was observed between FEP and TL. Our result is consistent with the hypothesis that psycho-social stress / adversities and stressful situations in people with schizophrenia affect TL rather than that telomere erosion contributes to the development of this disorder.

Background Cell senescence is a key process in age-associated dysfunction and diseases, notably chronic obstructive pulmonary disease (COPD). We previously identified phospholipase A2 receptor 1 (PLA2R1) as a positive regulator of cell senescence acting via Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signalling. Its role in pathology, however, remains unknown. Here, we assessed PLA2R1-induced senescence in COPD and lung emphysema pathogenesis. Methods We assessed cell senescence in lungs and cultured lung cells from patients with COPD and controls subjected to PLA2R1 knockdown, PLA2R1 gene transduction and treatment with the JAK1/2 inhibitor ruxolitinib. To assess whether PLA2R1 upregulation caused lung lesions, we developed transgenic mice overexpressing PLA2R1 (PLA2R1-TG) and intratracheally injected wild-type mice with a lentiviral vector carrying the Pla2r1 gene (LV-PLA2R1 mice). Results We found that PLA2R1 was overexpressed in various cell types exhibiting senescence characteristics in COPD lungs. PLA2R1 knockdown extended the population doubling capacity of these cells and inhibited their pro-inflammatory senescence-associated secretory phenotype (SASP). PLA2R1mediated cell senescence in COPD was largely reversed by treatment with the potent JAK1/2 inhibitor ruxolitinib. Five-month-old PLA2R1-TG mice exhibited lung cell senescence, and developed lung emphysema and lung fibrosis together with pulmonary hypertension. Treatment with ruxolitinib induced reversal of lung emphysema and fibrosis. LV-PLA2R1-treated mice developed lung emphysema within 4 weeks and this was markedly attenuated by concomitant ruxolitinib treatment. Conclusions Our data support a major role for PLA2R1 activation in driving lung cell senescence and lung alterations in COPD. Targeting JAK1/2 may represent a promising therapeutic approach for COPD.