Single cell transcriptomic analyses reveal diverse and dynamic changes of distinct populations of lung interstitial macrophages in hypoxia-induced pulmonary hypertension.

Introduction: Hypoxia is a common pathological driver contributing to various forms of pulmonary vascular diseases leading to pulmonary hypertension (PH). Pulmonary interstitial macrophages (IMs) play pivotal roles in immune and vascular dysfunction, leading to inflammation, abnormal remodeling, and fibrosis in PH. However, IMs' response to hypoxia and their role in PH progression remain largely unknown. We utilized a murine model of hypoxia-induced PH to investigate the repertoire and functional profiles of IMs in response to acute and prolonged hypoxia, aiming to elucidate their contributions to PH development. Methods: We conducted single-cell transcriptomic analyses to characterize the repertoire and functional profiles of murine pulmonary IMs following exposure to hypobaric hypoxia for varying durations (0, 1, 3, 7, and 21 days). Hallmark pathways from the mouse Molecular Signatures Database were utilized to characterize the molecular function of the IM subpopulation in response to hypoxia. Results: Our analysis revealed an early acute inflammatory phase during acute hypoxia exposure (Days 1-3), which was resolved by Day 7, followed by a pro-remodeling phase during prolonged hypoxia (Days 7-21). These phases were marked by distinct subpopulations of IMs: MHCIIhiCCR2+EAR2+ cells characterized the acute inflammatory phase, while TLF+VCAM1hi cells dominated the pro-remodeling phase. The acute inflammatory phase exhibited enrichment in interferon-gamma, IL-2, and IL-6 pathways, while the pro-remodeling phase showed dysregulated chemokine production, hemoglobin clearance, and tissue repair profiles, along with activation of distinct complement pathways. Discussion: Our findings demonstrate the existence of distinct populations of pulmonary interstitial macrophages corresponding to acute and prolonged hypoxia exposure, pivotal in regulating the inflammatory and remodeling phases of PH pathogenesis. This understanding offers potential avenues for targeted interventions, tailored to specific populations and distinct phases of the disease. Moreover, further identification of triggers for pro-remodeling IMs holds promise in unveiling novel therapeutic strategies for pulmonary hypertension.

Effect of nonsteroidal anti-inflammatory drugs (aspirin and naproxen) on inflammation-associated proteomic profiles in mouse plasma and prostate during TMPRSS2-ERG (fusion)-driven prostate carcinogenesis.

Recent preclinical studies have shown that the intake of nonsteroidal anti-inflammatory drugs (NSAIDs) aspirin and naproxen could be an effective intervention strategy against TMPRSS2-ERG fusion-driven prostate tumorigenesis. Herein, as a follow-up mechanistic study, employing TMPRSS2-ERG (fusion) positive tumors and plasma from TMPRSS2-ERG. Ptenflox/flox mice, we profiled the stage specific proteomic changes (focused on inflammatory circulating and prostate tissue/tumor-specific cytokines, chemokines, and growth factors/growth signaling-associated molecules) that contribute to prostate cancer (PCa) growth and progression in the TMPRSS2-ERG fusion-driven mouse model of tumorigenesis. In addition, the association of the protective effects of NSAIDs (aspirin 1400 ppm and naproxen 400 ppm) with the modulation of these specific molecular pathways was determined. A sandwich Elisa based membrane array-proteome profiler identifying 111 distinct signaling molecules was employed. Overall, the plasma and prostate tissue sample analyses identified 54 significant and differentially expressed cytokines, chemokines, and growth factors/growth signaling-associated molecules between PCa afflicted mice (TMPRSS2-ERG. Ptenflox/flox, age-matched noncancerous controls, NSAIDs-supplemented and no-drug controls). Bioinformatic analysis of the array outcomes indicated that the protective effect of NSAIDs was associated with reduced expression of (a) tumor promoting inflammatory molecules (M-CSF, IL-33, CCL22, CCL12, CX3CL1, CHI3L1, and CD93), (b) growth factors- growth signaling-associated molecules (Chemerin, FGF acidic, Flt-3 ligand, IGFBP-5, and PEDF), and (c) tumor microenvironment/stromal remodeling proteins MMP2 and MMP9. Overall, our findings corroborate the pathological findings that protective effects of NSAIDs in TMPSS2-ERG fusion-driven prostate tumorigenesis are associated with antiproliferative and anti-inflammatory effects and possible modulation of the immune cell enriched microenvironment.

Differential Effect of Non-Steroidal Anti-Inflammatory Drugs Aspirin and Naproxen against TMPRSS2-ERG (Fusion)-Driven and Non-Fusion-Driven Prostate Cancer.

The consumption of the non-steroidal anti-inflammatory drug (NSAID) aspirin is associated with a significant reduction in the risk of developing TMPRSS2-ERG (fusion)-positive prostate cancer (PCa) compared to fusion-negative PCa in population-based case-control studies; however, no extensive preclinical studies have been conducted to investigate and confirm these protective benefits. Thus, the focus of this study was to determine the potential usefulness of aspirin and another NSAID, naproxen, in PCa prevention, employing preclinical models of both TMPRSS2-ERG (fusion)-driven (with conditional deletion of Pten) and non-TMPRSS2-ERG-driven (Hi-Myc+/- mice) PCa. Male mice (n = 25 mice/group) were fed aspirin- (700 and 1400 ppm) and naproxen- (200 and 400 ppm) supplemented diets from (a) 6 weeks until 32 weeks of Hi-Myc+/- mice age; and (b) 1 week until 20 weeks post-Cre induction in the fusion model. In all NSAID-fed groups, compared to no-drug controls, there was a significant decrease in higher-grade adenocarcinoma incidence in the TMPRSS2-ERG (fusion)-driven PCa model. Notably, there were no moderately differentiated (MD) adenocarcinomas in the dorsolateral prostate of naproxen groups, and its incidence also decreased by ~79-91% in the aspirin cohorts. In contrast, NSAIDs showed little protective effect against prostate tumorigenesis in Hi-Myc+/- mice, suggesting that NSAIDs exert a specific protective effect against TMPRSS2-ERG (fusion)-driven PCa.

SIRT3 Is a Critical Regulator of Mitochondrial Function of Fibroblasts in Pulmonary Hypertension.

Pulmonary hypertension (PH) is a heterogeneous and life-threatening cardiopulmonary disorder in which mitochondrial dysfunction is believed to drive pathogenesis, although the underlying mechanisms remain unclear. To determine if abnormal SIRT3 (sirtuin 3) activity is related to mitochondrial dysfunction in adventitial fibroblasts from patients with idiopathic pulmonary arterial hypertension (IPAH) and hypoxic PH calves (PH-Fibs) and whether SIRT3 could be a potential therapeutic target to improve mitochondrial function, SIRT3 concentrations in control fibroblasts, PH-Fibs, and lung tissues were determined using quantitative real-time PCR and western blot. SIRT3 deacetylase activity in cells and lung tissues was determined using western blot, immunohistochemistry staining, and immunoprecipitation. Glycolysis and mitochondrial function in fibroblasts were measured using respiratory analysis and fluorescence-lifetime imaging microscopy. The effects of restoring SIRT3 activity (by overexpression of SIRT3 with plasmid, activation SIRT3 with honokiol, and supplementation with the SIRT3 cofactor nicotinamide adenine dinucleotide [NAD+]) on mitochondrial protein acetylation, mitochondrial function, cell proliferation, and gene expression in PH-Fibs were also investigated. We found that SIRT3 concentrations were decreased in PH-Fibs and PH lung tissues, and its cofactor, NAD+, was also decreased in PH-Fibs. Increased acetylation in overall mitochondrial proteins and SIRT3-specific targets (MPC1 [mitochondrial pyruvate carrier 1] and MnSOD2 [mitochondrial superoxide dismutase]), as well as decreased MnSOD2 activity, was identified in PH-Fibs and PH lung tissues. Normalization of SIRT3 activity, by increasing its expression with plasmid or with honokiol and supplementation with its cofactor NAD+, reduced mitochondrial protein acetylation, improved mitochondrial function, inhibited proliferation, and induced apoptosis in PH-Fibs. Thus, our study demonstrated that restoration of SIRT3 activity in PH-Fibs can reduce mitochondrial protein acetylation and restore mitochondrial function and PH-Fib phenotype in PH.

Local Complement Contributes to Pathogenic Activation of Lung Endothelial Cells in SARS-CoV-2 Infection.

Endothelial dysfunction and inflammation contribute to the vascular pathology of coronavirus disease (COVID-19). However, emerging evidence does not support direct infection of endothelial or other vascular wall cells, and thus inflammation may be better explained as a secondary response to epithelial cell infection. In this study, we sought to determine whether lung endothelial or other resident vascular cells are susceptible to productive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and how local complement activation contributes to endothelial dysfunction and inflammation in response to hypoxia and SARS-CoV-2-infected lung alveolar epithelial cells. We found that ACE2 (angiotensin-converting enzyme 2) and TMPRSS2 (transmembrane serine protease 2) mRNA expression in lung vascular cells, including primary human lung microvascular endothelial cells (HLMVECs), pericytes, smooth muscle cells, and fibroblasts, was 20- to 90-fold lower compared with primary human alveolar epithelial type II cells. Consistently, we found that HLMVECs and other resident vascular cells were not susceptible to productive SARS-CoV-2 infection under either normoxic or hypoxic conditions. However, viral uptake without replication (abortive infection) was observed in HLMVECs when exposed to conditioned medium from SARS-CoV-2-infected human ACE2 stably transfected A549 epithelial cells. Furthermore, we demonstrated that exposure of HLMVECs to conditioned medium from SARS-CoV-2-infected human ACE2 stably transfected A549 epithelial cells and hypoxia resulted in upregulation of inflammatory factors such as ICAM-1 (intercellular adhesion molecule 1), VCAM-1 (vascular cell adhesion molecule 1), and IL-6 (interleukin 6) as well as complement components such as C3 (complement C3), C3AR1 (complement C3a receptor 1), C1QA (complement C1q A chain), and CFB (complement factor B). Taken together, our data support a model in which lung endothelial and vascular dysfunction during COVID-19 involves the activation of complement and inflammatory signaling and does not involve productive viral infection of endothelial cells.

Human telomerase reverse transcriptase promotes the epithelial to mesenchymal transition in lung cancer cells by enhancing c-MET upregulation.

Human telomerase reverse transcriptase (hTERT), the essential catalytic subunit of telomerase, is associated with telomere homeostasis to prevent replicative senescence and cellular aging. However, hTERT reactivation also has been linked to the acquisition of several hallmarks of cancer, although the underlying mechanism beyond telomere extension remains elusive. This study demonstrated that hTERT overexpression promotes, whereas its inhibition by shRNA suppresses, epithelial-mesenchymal transition (EMT) in lung cancer cells (A549 and H1299). We found that hTERT modulates the expression of EMT markers E-cadherin, vimentin, and cytokeratin-18a through upregulation of the c-MET. Ectopic expression of hTERT induces expression of c-MET, while hTERT-shRNA treatment significantly decreases the c-MET level in A549 and H1299 through differential expression of p53 and c-Myc. Reporter assay suggests the regulation of c-MET expression by hTERT to be at the promoter level. An increase in c-MET level significantly promotes the expression of mesenchymal markers, including vimentin and N-cadherin, while a notable increase in epithelial markers E-cadherin and cytokeratin-18a is observed after the c-MET knockdown in A549.

Silibinin and non-melanoma skin cancers.

Skin is the largest human organ that shields the inner body from contact with xenobiotic and genotoxic agents, and in this process, the skin's cellular genome faces continuous stress due to direct exposure to these noxious factors. Accumulation of genetic stress results in genomic alterations leading to undesirable gene or protein alteration/expression in skin cells, which eventually causes the formation of non-melanoma skin cancers (NMSCs). Ultraviolet B (UVB) radiation from sun is the most prominent factor contributing to ∼5 million skin cancer cases (which are mostly NMSCs) in the United States (US) and western countries. UVB exposure causes aberrations in a range of biochemical and molecular pathways such as: thymine dimer formation, DNA damage, oxidative stress, inflammatory responses, altered cellular signaling, which ultimately contribute to the development of NMSCs. The focus of this review is to summarize the protective and preventive potential of silymarin and/or silibinin against UVB-induced NMSC in pre-clinical skin cancer studies. Over two decades of research has shown the strong potential of silibinin, a biologically active flavonolignan (crude form Silymarin) derived from milk thistle plant, against a wide range of cancers, including NMSCs. Silibinin protects against UVB-induced thymine dimer formation and in turn promotes DNA repair and/or initiates apoptosis in damaged cells via an increase in p53 levels. Additionally, silibinin has shown strong efficacy against NMSCs via its potential to target aberrant signaling pathways, and induction of anti-inflammatory responses. Overall, completed comprehensive studies suggest the potential use of silibinin to prevent and/or manage NMSCs in humans.