BMC Pulm Med. 2022 Apr 7;22(1):134. doi: 10.1186/s12890-022-01927-x.

ABSTRACT

BACKGROUND: The presence of familial interstitial lung disease (ILD) has been found to predict development of progressive pulmonary fibrosis. However, the role of non-ILD lung diseases in ILD patients' families has not yet been investigated. We aimed to identify associations between ILDs and non-ILD lung diseases from ILD patients' self-reported family health history.

METHODS: We analysed questionnaires on family health history of 1164 ILD patients for the occurrence of ILD and non-ILD lung disease in relatives. Logistic regression analysis was used to study associations with diagnosis groups.

RESULTS: Familial pulmonary fibrosis was reported by 20% of patients with idiopathic pulmonary fibrosis (IPF; OR 9.2, 95% CI 4.7-17.9), and 15% of patients with unclassifiable pulmonary fibrosis (OR 4.1, 95% CI 2.0-8.2). Familial occurrence was reported by 14% of patients with sarcoidosis (OR 3.3, 95% CI 1.9-5.8). Regarding non-ILD lung disease, significantly more patients with IPF (36%) reported lung cancer in their family (OR 2.3, 95% CI 1.4-3.5), and patients with hypersensitivity pneumonitis (18%) mostly reported COPD (OR 2.3, 95% CI 1.3-4.2). Comparison of sporadic and familial ILD patients' reports showed that emphysema (OR 4.6, 95% CI 1.8-11.6), and lung cancer (OR 2.4, 95% CI 1.2-4.9) were predictive for familial pulmonary fibrosis, particularly when reported both in a family (OR 16.7, 95% CI 3.2-86.6; p < 0.001).

CONCLUSIONS: Our findings provide evidence for clustering of ILD and non-ILD lung diseases in families and show that self-reported emphysema and lung cancer of relatives in this population predicts familial pulmonary fibrosis.

PMID:35392870 | DOI:10.1186/s12890-022-01927-x

Can Respir J. 2022 Mar 29;2022:1107673. doi: 10.1155/2022/1107673. eCollection 2022.

ABSTRACT

BACKGROUND: We have previously analysed serum autoantibody levels in patients with idiopathic pulmonary fibrosis (IPF), idiopathic nonspecific interstitial pneumonia (iNSIP), and healthy controls and identified the autoantibody against anti-myxovirus resistance protein-1 (MX1) to be a specific autoantibody in iNSIP. We found that a higher anti-MX1 autoantibody level was a significant predictor of a good prognosis in patients with non-IPF idiopathic interstitial pneumonias. In this retrospective study, we sought to clarify the prognostic significance of the anti-MX1 autoantibody in IPF.

METHODS: We measured anti-MX1 immunoglobulin (Ig) G, IgA, and IgM autoantibody levels by enzyme-linked immunosorbent assay in serum collected at the time of diagnosis from 71 patients with IPF diagnosed according to the 2018 IPF guideline. The gender-age-physiology (GAP) index was calculated in each case.

RESULTS: The study population (59 men and 12 women) had a median age of 67 years. Serum anti-MX1 IgG and IgA autoantibody levels correlated positively with GAP stage (p < 0.05). Univariate Cox proportional hazards regression analysis did not identify an elevated anti-MX1 IgG, IgA, or IgM autoantibody level as a significant prognostic factor; however, a higher anti-MX1 IgA autoantibody level heralded significantly poorer survival after adjustment for GAP stage (p=0.030) and for percent forced vital capacity and modified Medical Research Council score (p=0.018). Neither the anti-MX1 IgG autoantibody nor the IgM autoantibody could predict survival after these adjustments.

CONCLUSIONS: The serum anti-MX1 IgA autoantibody level is a significant prognostic factor in IPF. Further studies are needed to clarify the pathophysiological role of this autoantibody in IPF.

PMID:35391716 | PMC:PMC8983265 | DOI:10.1155/2022/1107673

J Investig Med High Impact Case Rep. 2022 Jan-Dec;10:23247096221084840. doi: 10.1177/23247096221084840.

ABSTRACT

Organizing pneumonia is a pulmonary disease of undefined etiology, with few reported cases in children. It may be secondary to chemotherapy, radiation therapy, infectious agents, or hematopoietic cell transplantation. We present a case of an 18-year-old boy who presented to a follow-up consult with respiratory symptoms at the age of 11 years, 8 years after finishing treatment for a prostatic relapse of a pelvic rhabdomyosarcoma. Chest radiography revealed nodular opacities in the left lung, the one in the left lower lobe with silhouette sign with the left hemidiaphragm. Chest computerized tomography showed 2 nodular lesions in the left upper lobe, one of them cavitated, and another nodular lesion in the left lower lobe; 2 of these nodules had surrounding ground-glass opacities. Microbiological work-up, including tuberculosis screening, was negative. Biopsy revealed findings suggestive of organizing pneumonia. He presented spontaneous resolution. This case presented a diagnostic challenge due to rarity of this condition and its indetermined association with the patient's history of rhabdomyosarcoma. With this case, the authors alert that organizing pneumonia must be considered in patients presenting with pulmonary lesions with a history of previous hematopoietic stem cell transplants, lung irradiation, or immunosuppression. Pulmonary metastases and secondary tumors must be considered as a differential diagnosis in patients with a heavily treated relapsed rhabdomyosarcoma.

PMID:35389278 | DOI:10.1177/23247096221084840

Chest. 2022 Apr 4:S0012-3692(22)00587-6. doi: 10.1016/j.chest.2022.03.042. Online ahead of print.

NO ABSTRACT

PMID:35390330 | DOI:10.1016/j.chest.2022.03.042

J Clin Invest. 2022 Apr 7:e157338. doi: 10.1172/JCI157338. Online ahead of print.

ABSTRACT

AbstractType 2 alveolar epithelial cells (AEC2s) function as progenitor cells in the lung. We have shown previously that failure of AEC2 regeneration results in progressive lung fibrosis in mice and is a cardinal feature of idiopathic pulmonary fibrosis (IPF). In this study, we identified a deficiency of a specific zinc transporter SLC39A8 (ZIP8) in AEC2s from both IPF lungs and lungs of old mice. Loss of ZIP8 expression was associated with impaired renewal capacity of AEC2s and enhanced lung fibrosis. ZIP8 regulation of AEC2 progenitor function was dependent on SIRT1. Replenishment with exogenous zinc and SIRT1 activation promoted self-renewal and differentiation of AEC2s from lung tissues of IPF patients and old mice. Deletion of Zip8 in AEC2s in mice impaired AEC2 renewal, increased susceptibility of the mice to bleomycin injury, and the mice developed spontaneous lung fibrosis. Therapeutic strategies to restore zinc metabolism and appropriate SIRT1 signaling could improve AEC2 progenitor function and mitigate ongoing fibrogenesis.

PMID:35389887 | DOI:10.1172/JCI157338

Am J Hosp Palliat Care. 2022 Apr 7:10499091221083575. doi: 10.1177/10499091221083575. Online ahead of print.

ABSTRACT

Background: Interstitial lung disease (ILD) is associated with poor quality of life (QoL) and high symptom burden. Studies evaluating the benefits of palliative care examined mainly idiopathic pulmonary fibrosis (IPF) patients. We aim to examine the impact of palliative care on a broader group of fibrotic ILD patients. Methods: Single center retrospective cohort study comparing deceased ILD patients who received outpatient palliative care services (palliative-intervention group) against a usual care group. Results: Of 63 subjects, 26 (41%) were in the palliative-intervention group and 37 (59%) in the usual care group. Median time to palliative care referral was 8.6 (IQR .3-21.2) months. Dyspnea-related disability was greater in the palliative-intervention group [mMRC dyspnea score 3.5(IQR 2-4) vs 2(IQR 2-4), P = .039], with more patients requiring long term oxygen therapy (70% vs 30%, P < .001). There was no difference in the median number of hospitalizations or length of stay in the last 6 months of life. Patients in the palliative-intervention group had a higher uptake of advance care planning (ACP) (39% vs 11%, P = .014), lower frequency of intensive care unit (ICU) admissions (5% vs 19%, P = .102) and were prescribed more opioids (96% vs 27%, P < .001) and benzodiazepines (39% vs 14%, P = .022). The palliative-intervention group experienced a longer median survival of 23.9 months (95% confidence interval [CI] 14.1-33.7) compared to the usual group (11.4 months [95% CI 5.4-17.3] (log-rank test: P = .023). Male gender was a strong predictor of 1-year mortality. Conclusions: The palliative-intervention group received earlier pharmacologic intervention for symptom relief. Healthcare utilization was not increased despite greater dyspnea-related disability.

PMID:35389277 | DOI:10.1177/10499091221083575

Tuberc Respir Dis (Seoul). 2022 Apr;85(2):122-136. doi: 10.4046/trd.2021.0141. Epub 2022 Jan 27.

ABSTRACT

Although chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) have distinct clinical features, both diseases may coexist in a patient because they share similar risk factors such as smoking, male sex, and old age. Patients with both emphysema in upper lung fields and diffuse ILD are diagnosed with combined pulmonary fibrosis and emphysema (CPFE), which causes substantial clinical deterioration. Patients with CPFE have higher mortality compared with patients who have COPD alone, but results have been inconclusive compared with patients who have idiopathic pulmonary fibrosis (IPF). Poor prognostic factors for CPFE include exacerbation, lung cancer, and pulmonary hypertension. The presence of interstitial lung abnormalities, which may be an early or mild form of ILD, is notable among patients with COPD, and is associated with poor prognosis. Various theories have been proposed regarding the pathophysiology of CPFE. Biomarker analyses have implied that this pathophysiology may be more closely associated with IPF development, rather than COPD or emphysema. Patients with CPFE should be advised to quit smoking and undergo routine lung function tests, and pulmonary rehabilitation may be helpful. Various pharmacologic agents and surgical approaches may be beneficial in patients with CPFE, but further studies are needed.

PMID:35385639 | DOI:10.4046/trd.2021.0141

Respir Res. 2022 Apr 5;23(1):81. doi: 10.1186/s12931-022-01998-8.

ABSTRACT

BACKGROUND: A small number of studies suggested that air pollution was associated with idiopathic pulmonary fibrosis (IPF) exacerbation, incidence and mortality. However, no studies to date were conducted in regions where air pollution is substantial. We aimed to investigate whether there are associations between acute increases in air pollution and hospitalization of patients with a confirmed primary diagnosis of IPF in Beijing.

METHODS: Daily count of IPF hospitalizations (International Classification of Disease-10th Revision, J84.1) was obtained from an administrative database for 2013-2017 while daily city-wide average concentrations of PM10, PM2.5, NO2, Ozone, SO2 were obtained from 35 municipal monitoring stations for the same period. The association between daily IPF hospitalization and average concentration of each pollutant was analyzed with a generalized additive model estimating Poisson distribution.

RESULTS: Daily 24-h mean PM2.5 concentration during 2013-2017 was 76.7 μg/m3. The relative risk (RR) of IPF hospitalization per interquartile range (IQR) higher (72 μg/m3) in PM2.5 was 1.049 (95% CI 1.024-1.074) and 1.031 (95% CI 1.007-1.056) for lag0 and moving averages 0-1 days respectively. No significant associations were observed for other lags. Statistically significant positive associations were also observed at lag0 with SO2, Ozone and NO2 (in men only). Positive associations were seen at moving averages 0-30 days for PM10 (RR per 86 μg/m3: 1.021, 95% CI 0.994-1.049), NO2 (RR per 30 μg/m3: 1.029, 95% CI 0.999-1.060), and SO2 (RR per 15 μg/m3: 1.060 (95% CI 1.025-1.097), but not with PM2.5 or Ozone.

CONCLUSIONS: Despite improvement in air quality since the implementation of clean air policy in 2013, acute exposure to higher levels of air pollution is significantly associated with IPF hospitalization in Beijing. Air quality policy should be continuously enforced to protect vulnerable IPF populations as well as the general public.

PMID:35382829 | DOI:10.1186/s12931-022-01998-8

J Pharm Pharm Sci. 2022;25:137-148. doi: 10.18433/jpps32306.

ABSTRACT

Periostin is a matricellular, nonstructural protein belonging to the fasciclin family and is encoded by the POSTN gene in humans. Periostin plays an important role in maintaining a normal tissue matrix in the lungs. Despite the vital role as a structural mediator in tissue growth and repair, periostin is involved in the pathogenic mechanism during tissue remodeling and fibrosis. Periostin is a chemoattractant mediator, promotes eosinophil recruitment and adhesion on the airways sub-epithelial membrane of asthmatic patients. POSTN gene was identified as one of the highly expressed genes induced by interleukins IL-13, IL-5 and IL-4 - the key cytokines of Th2 immune responses in the bronchial tissues of asthmatic patients. This review highlights the potential role of periostin as a validated biomarker in respiratory disease progression and its candidacy to predict the response to treatments targeting Th-2 cytokines in bronchial asthma. In addition, its potential role in COPD, IPF, lung cancer and lung infection, is also speculated. Keywords Periostin, Asthma, Pneumonia, COPD, Idiopathic pulmonary fibrosis, Biomarker.

PMID:35379385 | DOI:10.18433/jpps32306

Ecotoxicol Environ Saf. 2022 Apr 1;236:113451. doi: 10.1016/j.ecoenv.2022.113451. Online ahead of print.

ABSTRACT

Existing studies reported that some circular RNAs (circRNAs) play vital roles in the development of pulmonary fibrosis. However, few studies explored the biomarker potential of circRNAs for pulmonary fibrosis based on population data. Therefore, we aimed to identify peripheral blood circRNAs as potential biomarkers for diagnosing silicosis and idiopathic pulmonary fibrosis (IPF). In brief, an RNA-seq screening based on 4 silicosis cases and 4 controls was initially performed. Differentially expressed circRNAs were combined with the human serum circRNA dataset to identify overlapping serum-detectable circRNAs, followed by validation using the GEO dataset (3 IPF cases and 3 controls) and subsequent qRT-PCR, including 84 additional individuals. Following the above steps, 243 differentially expressed circRNAs were identified during the screening stage, with fold changes ≥ 1.5 and P < 0.05. Of note, the human serum circRNA dataset encompassed 28 of 243 circRNAs. GEO (GSE102660) validation revealed two highly expressed circRNAs (P < 0.05) in the IPF case group. Furthermore, at the enlarged sample validation stage, hsa_circ_0058493 was highly expressed in both silicosis and IPF cases (silicosis: P = 1.16 × 10-6; IPF: P = 7.46 × 10-5). Additionally, hsa_circ_0058493 expression was significantly increased in MRC-5 cells upon TGF-β1 treatment, while hsa_circ_0058493 knockdown inhibited the expression of fibrotic molecules by affecting the epithelial-mesenchymal transition process. These shreds of evidence indicated that hsa_circ_0058493 might serve as a novel biomarker for diagnosing silicosis and IPF.

PMID:35378401 | DOI:10.1016/j.ecoenv.2022.113451

Am J Respir Cell Mol Biol. 2022 Apr 4. doi: 10.1165/rcmb.2021-0428OC. Online ahead of print.

ABSTRACT

Idiopathic pulmonary fibrosis is a progressive lung disease with limited therapeutic options that is characterized by pathological fibroblast activation and aberrant lung remodeling with scar formation. Yes-associated protein (YAP) is a transcriptional coactivator that mediates mechanical and biochemical signals controlling fibroblast activation. We previously identified HMG-CoA reductase inhibitors (statins) as YAP inhibitors based on a high-throughput small-molecule screen in primary human lung fibroblasts. Here we report that several Aurora kinase inhibitors were also identified from the top hits of this screen. MK-5108, a highly selective inhibitor for Aurora kinase A (AURKA), induced YAP phosphorylation and cytoplasmic retention, and significantly reduced profibrotic gene expression in human lung fibroblasts. The inhibitory effect on YAP nuclear translocation and profibrotic gene expression is specific to inhibition of AURKA, but not Aurora kinase B or C, and is independent of the Hippo pathway kinases LATS1 and LATS2. Further characterization of the effects of MK-5108 demonstrate that it inhibits YAP nuclear localization indirectly via effects on actin polymerization and TGFβ signaling. In addition, MK-5108 treatment reduced lung collagen deposition in the bleomycin mouse model of pulmonary fibrosis. Our results reveal a novel role for AURKA in YAP-mediated profibrotic activity in fibroblasts and highlight the potential of small-molecule screens for YAP inhibitors for identification of novel agents with anti-fibrotic activity.

PMID:35377835 | DOI:10.1165/rcmb.2021-0428OC

Exp Lung Res. 2022 Apr 4:1-14. doi: 10.1080/01902148.2022.2055227. Online ahead of print.

ABSTRACT

Background: Idiopathic pulmonary fibrosis (IPF) is an interstitial disease of unknown origin, characterized by tissue fibrosis, for which currently there is no effective treatment. Macrophages, the main immune cells in lung tissue, are involved in the whole process of pulmonary fibrosis. In recent years, intercellular transformation has led to wide spread concern among pulmonary fibrosis researchers. Macrophages with flexible heterogeneity and plasticity participate in different physiological processes in the body. Cell chemokine receptor 8 (CCR8) is expressed in a variety of cells and plays a significant chemotactic role in the induction of cell activation and migration. It can also promote the differentiation of macrophages under certain environmental conditions. The current study is intended to explore the role of CCR8 in macrophage to myofibroblast transdifferentiation (MMT) in IPF. Methods: We conducted experiments using CCR8-specific small interfering RNA (siRNA), an autophagy inhibitor (3-methyladenine, 3-MA), and an agonist (rapamycin) to explore the underlying mechanisms of macrophage transdifferentiation into myofibroblast cells in transforming growth factor-beta (TGF-β)-induced pulmonary fibrosis. Results: TGF-β treatment increased the CCR8 protein level in a time- and dose-dependent manner in mouse alveolar macrophages, as well as macrophage transdifferentiation-related markers, including vimentin, collagen 1, and a-SMA, and cell migration. In addition, the levels of autophagy were enhanced in macrophages treated with TGF-β. We found that 3-MA, an autophagy inhibitor, decreased the expression levels of macrophage transdifferentiation-related markers and attenuated cell migration. Furthermore, the inhibition of CCR8 via CCR8-specific siRNA reduced the levels of autophagy and macrophage transdifferentiation-related markers, and inhibited the cell migration. Enhancing autophagy with rapamycin attenuated the inhibition effect of CCR8-specific siRNA on macrophage migration and the increase in myofibroblast marker proteins. Conclusions: Our findings showed that the macrophages exposed to TGF-β had the potential to transdifferentiate into myofibroblasts and CCR8 was involved in the process. The effect of CCR8 on TGF-β-induced macrophage transdifferentiation occurs mainly through autophagy. Targeting CCR8 may be a novel therapeutic strategy for the treatment of IPF.

PMID:35377281 | DOI:10.1080/01902148.2022.2055227

Br J Hosp Med (Lond). 2022 Mar 2;83(3):1-3. doi: 10.12968/hmed.2021.0201. Epub 2022 Mar 31.

NO ABSTRACT

PMID:35377209 | DOI:10.12968/hmed.2021.0201

Front Med (Lausanne). 2022 Mar 18;9:865334. doi: 10.3389/fmed.2022.865334. eCollection 2022.

NO ABSTRACT

PMID:35372425 | PMC:PMC8971624 | DOI:10.3389/fmed.2022.865334

Front Med (Lausanne). 2022 Mar 15;9:858339. doi: 10.3389/fmed.2022.858339. eCollection 2022.

ABSTRACT

Interstitial lung diseases (ILD) on the whole have variable prognoses, but there are those which manifest with fibrosis and are characterized by disease progression. Chief among these is idiopathic pulmonary fibrosis, but other ILDs, including autoimmune ILD and chronic hypersensitivity pneumonitis, may have a progressive fibrotic phenotype also. A usual interstitial pneumonia pattern of lung involvement is a prominent risk factor for such a course, suggesting shared fibrotic pathways that may be targeted by antifibrotic therapies. This brief review describes ILDs that are most commonly fibrotic, shared risk factors for development of PF-ILD, and evidence for antifibrotic use in their management.

PMID:35372405 | PMC:PMC8965041 | DOI:10.3389/fmed.2022.858339

Cureus. 2022 Feb 25;14(2):e22606. doi: 10.7759/cureus.22606. eCollection 2022 Feb.

ABSTRACT

Acute exacerbation (AE) in idiopathic pulmonary fibrosis (IPF) is unfortunate a deadly event with a very high mortality rate. Its occurrence is highly unpredictable, though few baseline risk factors have been identified. The revised definition of AE is more precise with clarity on defined parameters. However, no clear guidelines exist on treatment, with most therapies showing inconsistent benefits. Both the approved anti-fibrotic (pirfenidone and nintedanib) have shown equal efficacy in reducing the decline in lung functions, with few studies suggesting a drop in AE. We report a case of a patient with IPF with mildly impaired lung functions who was initiated on pirfenidone with dose titrated on a weekly basis but developed AE-IPF on day 10 of starting pirfenidone and after four days of doubling the dose from 600 mg/day to 1,200 mg/day. This raised the suspicion of whether pirfenidone played any role in this unfortunate event. With no response to conventional therapy of steroids and non-invasive ventilation for AE-IPF, initialization of nintedanib led to recovery with discharge of the patient in two weeks of hospitalization. This case highlights inadequacy in knowledge about the effects of these anti-fibrotics in IPF and recommends close monitoring in the future.

PMID:35371648 | PMC:PMC8957895 | DOI:10.7759/cureus.22606

Front Pharmacol. 2022 Mar 17;13:830554. doi: 10.3389/fphar.2022.830554. eCollection 2022.

ABSTRACT

Reactive oxygen species (ROS)-mediated alveolar epithelial cell (AEC) injury and apoptosis are considered to be the initiating link of idiopathic pulmonary fibrosis (IPF), and protecting AECs can alleviate IPF. This study aimed to explore the protective effect of number 2 Feibi recipe (FBR-2) medicated serum on H2O2-mediated oxidative stress injury in AECs and further explore its mechanism. We found that FBR-2 can regulate downstream antioxidant enzymes expression by activating nuclear factor erythroid 2-related factor 2 (Nrf2), reducing the level of intracellular ROS, protecting mitochondrial function and improving cell survival. FBR-2 can also activate mitophagy through the PINK1/Parkin pathway. Moreover, FBR-2 can inhibit apoptosis by blocking the mitochondrial apoptosis mechanism. In summary, these data indicate that FBR-2 medicated serum can inhibit H2O2-mediated oxidative stress damage in AECs by regulating the balance of mitophagy/apoptosis. This study provides new evidence for the antifibrotic effect of FBR-2 and provides new drug candidates for the clinical treatment of IPF.

PMID:35370684 | PMC:PMC8968876 | DOI:10.3389/fphar.2022.830554

Chron Respir Dis. 2022 Jan-Dec;19:14799731221089319. doi: 10.1177/14799731221089319.

ABSTRACT

IMPORTANCE: Cough is a common symptom in idiopathic interstitial lung diseases (ILDs), there is little information of its management in primary care. The objective of this study was to explore the frequency of cough-related consultations and the medications prescribed to patients with ILDs in primary care.

METHODS: This retrospective cohort study used electronic medical records (EMR) from Manitoba primary care providers participating in the Manitoba Primary Care Research Network repository (2014-2019). Cough-related consults and the subsequent medications prescribed to patients with ILDs were identified in the EMR.

RESULTS: 295 patients with ILDs were identified, 73 (25%) of them had 141 cough-related consultations (mean 1.9, SD 1.3) during the period studied. In 50 (35%) of the consultations, patients were prescribed one or more of the following: inhaled bronchodilators (34%), nasal corticoids (18%), codeine/opiates (18%), antibiotics (14%), inhaled corticoids (14%), proton pump inhibitors (8%), cough preparations (6%), antihistamines (4%), and oral corticoids (2%). 13 (26%) subsequent cough-related consultations were identified within 6 months, mainly among patients who were prescribed cough preparations, nasal corticoids, antihistamines, and antibiotics.

CONCLUSION: One-quarter of patients with ILDs consulted primary care due to cough, and about a third of them received a prescription to address potentially underlying causes of cough. Although further studies are required to explore the effect of the medications prescribed, recurrent cough consultations suggested that cough preparations, nasal corticoids, and antihistamines are among the least effective treatments. More research is needed to understand the causes and optimal treatment of cough in patients with ILDs.

PMID:35369764 | DOI:10.1177/14799731221089319

Kobe J Med Sci. 2021 Nov 2;67(3):E84-E91.

ABSTRACT

Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease characterized by progressive lung fibrosis and obliteration of normal alveolar structures. Myofibroblasts play a central role in the progression of IPF by producing excess amount of extracellular matrix, and these myofibroblasts show heterogenous origins including resident fibroblasts, epithelial cells via epithelial to mesenchymal transition (EMT) and endothelial cell (EC) via endothelial to mesenchymal transition (EndMT). Although lung aging has been considered as essential mechanisms through abnormal activation of epithelial cells and fibroblasts, little is known about a role of EC senescence in the pathogenesis of IPF. Here, we reveal a detrimental role of EC senescence in IPF by utilizing unique EC-specific progeroid mice. EC-specific progeroid mice showed deteriorated pulmonary fibrosis in association with an accelerated EndMT in the lungs after intratracheal bleomycin instillation. We further confirmed that premature senescent ECs were susceptible to EndMT in vitro. Because senescent cells affect nearby cells through senescence-associated secretory phenotype (SASP), we assessed a potential role of the EC-SASP in EMT and myofibroblastic transition of resident fibroblasts. EC-SASP enhanced the myofibroblastic transition in resident fibroblasts, while no effect was detected on EMT. Our data revealed a previously unknown role of EC senescence in the progression of IPF, and thus rejuvenating ECs and/or inhibiting EC-SASP is an attracting therapeutic strategy for the treatment of IPF.

PMID:35367994

PLoS Comput Biol. 2022 Apr 1;18(4):e1010025. doi: 10.1371/journal.pcbi.1010025. Online ahead of print.

ABSTRACT

Advances in single-cell RNA sequencing (scRNA-seq) have led to successes in discovering novel cell types and understanding cellular heterogeneity among complex cell populations through cluster analysis. However, cluster analysis is not able to reveal continuous spectrum of states and underlying gene expression programs (GEPs) shared across cell types. We introduce scAAnet, an autoencoder for single-cell non-linear archetypal analysis, to identify GEPs and infer the relative activity of each GEP across cells. We use a count distribution-based loss term to account for the sparsity and overdispersion of the raw count data and add an archetypal constraint to the loss function of scAAnet. We first show that scAAnet outperforms existing methods for archetypal analysis across different metrics through simulations. We then demonstrate the ability of scAAnet to extract biologically meaningful GEPs using publicly available scRNA-seq datasets including a pancreatic islet dataset, a lung idiopathic pulmonary fibrosis dataset and a prefrontal cortex dataset.

PMID:35363784 | DOI:10.1371/journal.pcbi.1010025