Role of the HIF-1 signaling pathway in chronic obstructive pulmonary disease

Alleviatory Role of Panax Notoginseng Saponins in Modulating Inflammation and Pulmonary Vascular Remodeling in Chronic Obstructive Pulmonary Disease: mechanisms and Implications

COPD is an inflammatory lung disease that limits airflow and remodels the pulmonary vascular system. This study delves into the therapeutic potential and mechanistic underpinnings of Panax notoginseng Saponins (PNS) in alleviating inflammation and pulmonary vascular remodeling in a COPD rat model. Symmap and ETCM databases provided Panax notoginseng-related target genes, and the CTD and DisGeNET databases provided COPD-related genes. Intersection genes were subjected to protein-protein interaction analysis and pathway enrichment to identify downstream pathways. A COPD rat model was established, with groups receiving varying doses of PNS and a Roxithromycin control. The pathological changes in lung tissue and vasculature were examined using histological staining, while molecular alterations were explored through ELISA, RT-PCR, and Western blot. Network pharmacology research suggested PNS may affect the TLR4/NF-κB pathway linked to COPD development. The study revealed that, in contrast to the control group, the COPD model exhibited a significant increase in inflammatory markers and pathway components such as TLR4, NF-κB, HIF-1α, VEGF, ICAM-1, SELE mRNA, and serum TNF-α, IL-8, and IL-1β. Treatment with PNS notably decreased these markers and mitigated inflammation around the bronchi and vessels. Taken together, the study underscores the potential of PNS in reducing lung inflammation and vascular remodeling in COPD rats, primarily via modulation of the TLR4/NF-κB/HIF-1α/VEGF pathway. This research offers valuable insights for developing new therapeutic strategies for managing and preventing COPD.

Melatonin and mesenchymal stem cells co-administration alleviates chronic obstructive pulmonary disease via modulation of angiogenesis at the vascular-alveolar unit

Chronic obstructive pulmonary disease (COPD) is considered a severe disease mitigating lung physiological functions with high mortality outcomes, insufficient therapy, and pathophysiology pathways which is still not fully understood. Mesenchymal stem cells (MSCs) derived from bone marrow play an important role in improving the function of organs suffering inflammation, oxidative stress, and immune reaction. It might also play a role in regenerative medicine, but that is still questionable. Additionally, Melatonin with its known antioxidative and anti-inflammatory impact is attracting attention nowadays as a useful treatment. We hypothesized that Melatonin may augment the effect of MSCs at the level of angiogenesis in COPD. In our study, the COPD model was established using cigarette smoking and lipopolysaccharide. The COPD rats were divided into four groups: COPD group, Melatonin-treated group, MSC-treated group, and combined treated group (Melatonin-MSCs). We found that COPD was accompanied by deterioration of pulmonary function tests in response to expiratory parameter affection more than inspiratory ones. This was associated with increased Hypoxia inducible factor-1α expression and vascular endothelial growth factor level. Consequently, there was increased CD31 expression indicating increased angiogenesis with massive enlargement of airspaces and thinning of alveolar septa with decreased mean radial alveolar count, in addition to, inflammatory cell infiltration and disruption of the bronchiolar epithelial wall with loss of cilia and blood vessel wall thickening. These findings were improved significantly when Melatonin and bone marrow-derived MSCs were used as a combined treatment proving the hypothesized target that Melatonin might augment MSCs aiming at vascular changes.

Immune Dysregulation in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a disease whose incidence increase with age and is characterised by chronic inflammation and significant immune dysregulation. Inhalation of toxic substances cause oxidative stress in the lung tissue as well as airway inflammation, under the recruitment of chemokines, immune cells gathered and are activated to play a defensive role. However, persistent inflammation damages the immune system and leads to immune dysregulation, which is mainly manifested in the reduction of the body's immune response to antigens, and immune cells function are impaired, further destroy the respiratory defensive system, leading to recurrent lower respiratory infections and progressive exacerbation of the disease, thus immune dysregulation play an important role in the pathogenesis of COPD. This review summarizes the changes of innate and adaptive immune-related cells during the pathogenesis of COPD, aiming to control COPD airway inflammation and improve lung tissue remodelling by regulating immune dysregulation, for further reducing the risk of COPD progression and opening new avenues of therapeutic intervention in COPD.

miR‑186‑5p regulates the inflammatory response of chronic obstructive pulmonary disorder by targeting HIF‑1α

Chronic obstructive pulmonary disorder (COPD) is a chronic respiratory disease that is a major cause of morbidity and mortality worldwide. Previous studies have shown that miR‑186‑5p expression is significantly increased in COPD and is involved in multiple physiological and pathological processes. However, the role of miRNA‑186‑5p in the inflammatory response of COPD remains unclear. In this study, an in vitro model of COPD was established using lipopolysaccharide (LPS)‑induced human bronchial epithelial cells (BEAS‑2B). CCK‑8 assays, flow cytometry, and a Muse cell analyzer were used to determine cell viability, cell cycle distribution, and apoptosis, respectively. The production of TNF‑α and IL‑6 were measured by ELISA. Reverse‑transcription‑quantitative PCR and western blotting were used to analyze mRNA and protein expression levels. The targeting relation between miR‑186‑5p and HIF‑1α was discovered using dual‑luciferase reporter assays. The results showed that transfection of miR‑186‑5p inhibitor inhibited cell proliferation and promoted cell apoptosis in the LPS‑induced BEAS‑2B cells. Inhibition of miR‑186‑5p markedly increased the levels of TNF‑α and IL‑6. miR‑186‑5p directly targeted and negatively regulated HIF‑1α expression. In addition, inhibition of miR‑186‑5p increased the expression of the NF‑κB pathway protein p‑p65. In conclusion, it was found that inhibiting miR‑186‑5p may improve inflammation of COPD through HIF‑1α in LPS‑induced BEAS‑2B cells, possibly by regulating NF‑κB signaling. These findings provide a novel potential avenue for the clinical management of COPD. Future research is required to determine the mechanism of the interaction between miR‑186‑5p and HIF‑1α in COPD.

Effects of a physical exercise program on HIF-1α in people with Chronic Obstructive Pulmonary Disease living at high altitude: study protocol for a clinical trial

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is a chronic, noncommunicable disease characterized by hypoxemia, with altered lung function, dyspnea on mild exertion, limited tolerance to physical exertion, and functional impairment. Physical exercise has been recommended worldwide as an efficient strategy to improve the autonomy and quality of life of patients affected by COPD. However, the adaptive molecular mechanisms occurring in these patients after the exposure to the hypoxic stimulus triggered by physical exercise have currently not been described in populations living at high altitude.

METHODS

The clinical trial we are presenting here consists of a quasi-experimental design with longitudinal analysis of repeated measures, with intra- and inter-group comparisons, measuring primary and secondary variables in 4 temporal points. Participants will be people with a diagnosis of COPD residing at high altitudes (> 2600 m), without oncological, renal, cardiac, or musculoskeletal comorbidities with a low level of physical activity. The intervention will be an 8-week program of physical exercise of resistance and muscular strength (8-WVP) which will be carried out at home. Primary outcome variables will be the expression of HIF-1α, VEGF, and EPO. As secondary outcome variables, we will consider lung function (measured by spirometry), physical performance (measured by ergospirometry and dynamometry), and hematological parameters.

DISCUSSION

The results obtained after the clinical trial proposed here will promote knowledge on the expression of signaling proteins as an adaptive response to hypoxia in people with COPD living at high altitude, which will be relevant because there are not data on this population group. The knowledge generated from the application of this protocol will increase the pathophysiological understanding of the disease and future medical and therapeutic decision-making based on physical exercise prescription. TRIAL REGISTRATION {2A}: NCT04955977 [ClinicalTrials.gov]-NCT04955977 [WHO ICRTP]. First Posted: July 9, 2021.

Proteomics analysis of lung tissue reveals protein makers for the lung injury of adjuvant arthritis rats

Lung injury is one of the common extra‑articular lesions in rheumatoid arthritis (RA). Due to its insidious onset and no obvious clinical symptoms, it can be easily dismissed in the early stage of diagnosis, which is one of the reasons that leads to a decline of the quality of life and subsequent death of patients with RA. However, its pathogenesis is still unclear and there is a lack of effective therapeutic targets. In the present study, tandem mass tag‑labeled proteomics was used to research the lung tissue proteins in RA model (adjuvant arthritis, AA) rats that had secondary lung injury. The aim of the present study was to identify the differentially expressed proteins related to RA‑lung injury, determine their potential role in the pathogenesis of RA‑lung injury and provide potential targets for clinical treatment. Lung tissue samples were collected from AA‑lung injury and normal rats. The differentially expressed proteins (DEPs) were identified by tandem mass spectrometry. Bioinformatic analysis was used to assess the biological processes and signaling pathways associated with these DEPs. A total of 310 DEPs were found, of which 244 were upregulated and 66 were downregulated. KEGG anlysis showed that 'fatty acid degradation', 'fatty acid metabolism', 'fatty acid elongation', 'complement and coagulation cascades', 'peroxisome proliferator‑activated receptor signaling pathway' and 'hypoxia‑inducible factor signaling pathway' were significantly upregulated in the lung tissues of AA‑lung injury. Immunofluorescence staining confirmed the increased expression of clusterin, serine protease inhibitors and complement 1qc in lung tissue of rats with AA lung injury. In the present study, the results revealed the significance of certain DEPs (for example, C9, C1qc and Clu) in the occurrence and development of RA‑lung injury and provided support through experiments to identify potential biomarkers for the early diagnosis and prevention of RA‑lung injury.

Effects of hypoxia on bronchial and alveolar epithelial cells linked to pathogenesis in chronic lung disorders

Introduction: Chronic lung disorders involve pathological alterations in the lung tissue with hypoxia as a consequence. Hypoxia may influence the release of inflammatory mediators and growth factors including vascular endothelial growth factor (VEGF) and prostaglandin (PG)E2. The aim of this work was to investigate how hypoxia affects human lung epithelial cells in combination with profibrotic stimuli and its correlation to pathogenesis.

Methods: Human bronchial (BEAS-2B) and alveolar (hAELVi) epithelial cells were exposed to either hypoxia (1% O2) or normoxia (21% O2) during 24 h, with or without transforming growth factor (TGF)-β1. mRNA expression of genes and proteins related to disease pathology were analysed with qPCR, ELISA or immunocytochemistry. Alterations in cell viability and metabolic activity were determined.

Results: In BEAS-2B and hAELVi, hypoxia significantly dowregulated genes related to fibrosis, mitochondrial stress, oxidative stress, apoptosis and inflammation whereas VEGF receptor 2 increased. Hypoxia increased the expression of Tenascin-C, whereas both hypoxia and TGF-β1 stimuli increased the release of VEGF, IL-6, IL-8 and MCP-1 in BEAS-2B. In hAELVi, hypoxia reduced the release of fibroblast growth factor, epidermal growth factor, PGE2, IL-6 and IL-8, whereas TGF-β1 stimulus significantly increased the release of PGE2 and IL-6. TGF-β1 stimulated BEAS-2B cells showed a decreased release of VEGF-A and IL-8, while TGF-β1 stimulated hAELVi cells showed a decreased release of PGE2 and IL-8 during hypoxia compared to normoxia. Metabolic activity was significantly increased by hypoxia in both epithelial cell types.

Discussion: In conclusion, our data indicate that bronchial and alveolar epithelial cells respond differently to hypoxia and profibrotic stimuli. The bronchial epithelium appears more responsive to changes in oxygen levels and remodelling processes compared to the alveoli, suggesting that hypoxia may be a driver of pathogenesis in chronic lung disorders.

Hypoxia-inducible factor 1-alpha is a driving mechanism linking chronic obstructive pulmonary disease to lung cancer

Patients with chronic obstructive pulmonary disease (COPD), irrespective of their smoking history, are more likely to develop lung cancer than the general population. This is mainly because COPD is characterized by chronic persistent inflammation and hypoxia, which are the risk factors for lung cancer. However, the mechanisms underlying this observation are still unknown. Hypoxia-inducible factor 1-alpha (HIF-1α) plays an important role in the crosstalk that exists between inflammation and hypoxia. Furthermore, HIF-1α is the main regulator of somatic adaptation to hypoxia and is highly expressed in hypoxic environments. In this review, we discuss the molecular aspects of the crosstalk between hypoxia and inflammation, showing that HIF-1α is an important signaling pathway that drives COPD progression to lung cancer. Here, we also provide an overview of HIF-1α and its principal regulatory mechanisms, briefly describe HIF-1α-targeted therapy in lung cancer, and summarize substances that may be used to target HIF-1α at the level of COPD-induced inflammation.

Cigarette smoke-induced airspace disease in mice develops independently of HIF-1α signaling in leukocytes

The pathogenesis of chronic obstructive pulmonary disease (COPD), a prevalent disease primarily caused by cigarette smoke exposure, is incompletely elucidated. Studies in humans and mice have suggested that hypoxia-inducible factor-1α (HIF-1α) may play a role. Reduced lung levels of HIF-1α are associated with decreased vascular density, whereas increased leukocyte HIF-1α may be responsible for increased inflammation. To elucidate the specific role of leukocyte HIF-1α in COPD, we exposed transgenic mice with conditional deletion or overexpression of HIF-1α in leukocytes to cigarette smoke for 7 mo. Outcomes included pulmonary physiology, aerated lung volumes via microcomputed tomography, lung morphometry and histology, and cardiopulmonary hemodynamics. On aggregate, cigarette smoke increased the aerated lung volume, quasi-static lung compliance, inspiratory capacity of all strains while reducing the total alveolar septal volume. Independent of smoke exposure, mice with leukocyte-specific HIF-1α overexpression had increased quasi-static compliance, inspiratory capacity, and alveolar septal volume compared with mice with leukocyte-specific HIF-1α deletion. However, the overall development of cigarette smoke-induced lung disease did not vary relative to control mice for either of the conditional strains. This suggests that the development of murine cigarette smoke-induced airspace disease occurs independently of leukocyte HIF-1α signaling.

Network Pharmacology and Experimental Verification Revealed the Mechanism of Yiqi Jianpi Recipe on Chronic Obstructive Pulmonary Disease

Objective

The study aimed to explore the active ingredients, targets, and mechanism of action of Yiqi Jianpi recipe (YQJPR) in the treatment of COPD based on the network pharmacology and COPD rat models.

Methods

The active ingredients and targets of YQJPR were collected by TCMSP. Disease-related protein targets were obtained from GeneCards. The Venn diagram was used to show the key therapeutic targets of COPD in YQJPR. The PPI network was established by STRING, and cytoHubba plug-in was used to screen the core targets within the network. GO functional enrichment and KEGG pathway enrichment analysis were performed to describe the functions and pathways of the core targets. Cytoscape software was used to construct the ingredient-target network and the core target-enrichment pathway network. The chemical constituents of YQJPR were analyzed by HPLC-MS/MS.

Results

The network pharmacology showed 152 active ingredients and 225 targets in YQJPR for the treatment of COPD. The key active ingredients were quercetin, luteolin, kaempferol, tanshinone IIA, and baicalein. The contents of quercetin and luteolin in YQJPR were quantitatively measured by HPLC-MS/MS. 22 core genes were screened, including AKT1, IL-6, JUN, VEGFA, and CASP3, which were mainly involved in BPs such as cell proliferation and differentiation, oxidative/chemical stress, and regulation of DNA-binding transcription factor activity and regulated viral infection, tumor, HIF-1, MAPK, TNF, and IL-17 pathways. Animal experiments showed that YQJPR could significantly reduce the expression of p-ERK1/2, p-Akt, c-Myc, cleaved caspase-3, and p-Stat3 in lung tissue (p < 0.05). HE staining showed that, compared with the model group, YQJPR significantly improved lung tissue morphology and reduced lung inflammation in rats.

Conclusion

The effects of YQJPR on COPD may involve multiple components, pathways, and targets. This study provides new ideas for further and more comprehensive exploration of the therapeutic effect of YQJPR on COPD in the future.

VEGF Receptor 1 Promotes Hypoxia-Induced Hematopoietic Progenitor Proliferation and Differentiation

Although it is well known that hypoxia incites unleashed cellular inflammation, the mechanisms of exaggerated cellular inflammation in hypoxic conditions are not known. We observed augmented proliferation of hematopoietic stem and progenitor cells (HSPC), precursors of inflammatory leukocytes, in mice under hypoxia. Consistently, a transcriptomic analysis of human HSPC exposed to hypoxic conditions revealed elevated expression of genes involved in progenitor proliferation and differentiation. Additionally, bone marrow cells in mice expressed high amount of vascular endothelial growth factor (VEGF), and HSPC elevated VEGF receptor 1 (VEGFr1) and its target genes in hypoxic conditions. In line with this, VEGFr1 blockade in vivo and in vitro decreased HSPC proliferation and attenuated inflammation. In silico and ChIP experiments demonstrated that HIF-1α binds to the promoter region of VEGFR1. Correspondingly, HIF1a silencing decreased VEGFr1 expression in HSPC and diminished their proliferation. These results indicate that VEGF signaling in HSPC is an important mediator of their proliferation and differentiation in hypoxia-induced inflammation and represents a potential therapeutic target to prevent aberrant inflammation in hypoxia-associated diseases.

Dysregulated Cell Signaling in Pulmonary Emphysema

Pulmonary emphysema is characterized by the destruction of alveolar septa and irreversible airflow limitation. Cigarette smoking is the primary cause of this disease development. It induces oxidative stress and disturbs lung physiology and tissue homeostasis. Alveolar type II (ATII) cells have stem cell potential and can repair the denuded epithelium after injury; however, their dysfunction is evident in emphysema. There is no effective treatment available for this disease. Challenges in this field involve the large complexity of lung pathophysiological processes and gaps in our knowledge on the mechanisms of emphysema progression. It implicates dysregulation of various signaling pathways, including aberrant inflammatory and oxidative responses, defective antioxidant defense system, surfactant dysfunction, altered proteostasis, disrupted circadian rhythms, mitochondrial damage, increased cell senescence, apoptosis, and abnormal proliferation and differentiation. Also, genetic predispositions are involved in this disease development. Here, we comprehensively review studies regarding dysregulated cell signaling, especially in ATII cells, and their contribution to alveolar wall destruction in emphysema. Relevant preclinical and clinical interventions are also described.

Drosophila Trachea as a Novel Model of COPD

COPD, a chronic obstructive pulmonary disease, is one of the leading causes of death worldwide. Clinical studies and research in rodent models demonstrated that failure of repair mechanisms to cope with increased ROS and inflammation in the lung leads to COPD. Despite this progress, the molecular mechanisms underlying the development of COPD remain poorly understood, resulting in a lack of effective treatments. Thus, an informative, simple model is highly valued and desired. Recently, the cigarette smoke-induced Drosophila COPD model showed a complex set of pathological phenotypes that resemble those seen in human COPD patients. The Drosophila trachea has been used as a premier model to reveal the mechanisms of tube morphogenesis. The association of these mechanisms to structural changes in COPD can be analyzed by using Drosophila trachea. Additionally, the timeline of structural damage, ROS, and inflammation can be studied in live organisms using fluorescently-tagged proteins. The related function of human COPD genes identified by GWAS can be screened using respective fly homologs. Finally, the Drosophila trachea can be used as a high-throughput drug screening platform to identify novel treatments for COPD. Therefore, Drosophila trachea is an excellent model that is complementary to rodent COPD models.

Lipid Metabolism Disorders in the Comorbid Course of Nonalcoholic Fatty Liver Disease and Chronic Obstructive Pulmonary Disease

Non-alcoholic fatty liver disease (NAFLD) is currently among the most common liver diseases. Unfavorable data on the epidemiology of metabolic syndrome and obesity have increased the attention of clinicians and researchers to the problem of NAFLD. The research results allow us to emphasize the systemicity and multifactoriality of the pathogenesis of liver parenchyma lesion. At the same time, many aspects of its classification, etiology, and pathogenesis remain controversial. Local and systemic metabolic disorders are also a part of the pathogenesis of chronic obstructive pulmonary disease and can influence its course. The present article analyzes the metabolic pathways mediating the links of impaired lipid metabolism in NAFLD and chronic obstructive pulmonary disease (COPD). Free fatty acids, cholesterol, and ceramides are involved in key metabolic and inflammatory pathways underlying the pathogenesis of both diseases. Moreover, inflammation and lipid metabolism demonstrate close links in the comorbid course of NAFLD and COPD.

Patients with obstructive sleep apnea present with chronic upregulation of serum HIF-1α protein

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a chronic condition that is characterized by recurrent pauses in breathing during sleep causing intermittent hypoxia. The main factor responsible for oxygen metabolism homeostasis is hypoxia-inducible factor 1 (HIF-1), comprised of 2 subunits: α (oxygen sensitive) and β. The aim of the study was to investigate the HIF-1α serum protein level and mRNA HIF-1α expression in patients with OSA and a healthy control group and determine their evening-morning variation and association with polysomnography parameters.

METHODS

Eighty-four individuals were enrolled in the study. All patients underwent polysomnography examination and based on the results were divided into 2 groups: OSA group (n = 60) and control group (n = 24). Peripheral blood was collected in the evening before and in the morning after the polysomnography. HIF-1α expression was evaluated on protein in blood serum and mRNA level in peripheral blood leukocytes.

RESULTS

HIF-1α serum protein concentration was higher in patients with OSA compared with control patients in both the evening (1,490.1 vs. 727.0 pg/mL; P < .001) and the morning (1,368.9 vs. 702.1 pg/mL; P < .001) samples. There was no difference between evening and morning HIF-1α serum protein level in either group. No differences were observed in HIF-1α mRNA expression between the OSA and control group. Additionally, evening and morning HIF-1α serum protein level correlated with number of desaturations during sleep (r = .384, P < .001 and r = .433, P < .001, respectively).

CONCLUSIONS

Observed differences in HIF-1α serum protein level between the OSA and the control groups without difference between evening and morning measurements suggest chronic increase in this protein concentration by intermittent nocturnal hypoxia in OSA.

Chronic Obstructive Pulmonary Disease and the Cardiovascular System: Vascular Repair and Regeneration as a Therapeutic Target

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide and encompasses chronic bronchitis and emphysema. It has been shown that vascular wall remodeling and pulmonary hypertension (PH) can occur not only in patients with COPD but also in smokers with normal lung function, suggesting a causal role for vascular alterations in the development of emphysema. Mechanistically, abnormalities in the vasculature, such as inflammation, endothelial dysfunction, imbalances in cellular apoptosis/proliferation, and increased oxidative/nitrosative stress promote development of PH, cor pulmonale, and most probably pulmonary emphysema. Hypoxemia in the pulmonary chamber modulates the activation of key transcription factors and signaling cascades, which propagates inflammation and infiltration of neutrophils, resulting in vascular remodeling. Endothelial progenitor cells have angiogenesis capabilities, resulting in transdifferentiation of the smooth muscle cells via aberrant activation of several cytokines, growth factors, and chemokines. The vascular endothelium influences the balance between vaso-constriction and -dilation in the heart. Targeting key players affecting the vasculature might help in the development of new treatment strategies for both PH and COPD. The present review aims to summarize current knowledge about vascular alterations and production of reactive oxygen species in COPD. The present review emphasizes on the importance of the vasculature for the usually parenchyma-focused view of the pathobiology of COPD.

Influence of Hypoxia on the Epithelial-Pathogen Interactions in the Lung: Implications for Respiratory Disease

Under normal physiological conditions, the lung remains an oxygen rich environment. However, prominent regions of hypoxia are a common feature of infected and inflamed tissues and many chronic inflammatory respiratory diseases are associated with mucosal and systemic hypoxia. The airway epithelium represents a key interface with the external environment and is the first line of defense against potentially harmful agents including respiratory pathogens. The protective arsenal of the airway epithelium is provided in the form of physical barriers, and the production of an array of antimicrobial host defense molecules, proinflammatory cytokines and chemokines, in response to activation by receptors. Dysregulation of the airway epithelial innate immune response is associated with a compromised immunity and chronic inflammation of the lung. An increasing body of evidence indicates a distinct role for hypoxia in the dysfunction of the airway epithelium and in the responses of both innate immunity and of respiratory pathogens. Here we review the current evidence around the role of tissue hypoxia in modulating the host-pathogen interaction at the airway epithelium. Furthermore, we highlight the work needed to delineate the role of tissue hypoxia in the pathophysiology of chronic inflammatory lung diseases such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease in addition to novel respiratory diseases such as COVID-19. Elucidating the molecular mechanisms underlying the epithelial-pathogen interactions in the setting of hypoxia will enable better understanding of persistent infections and complex disease processes in chronic inflammatory lung diseases and may aid the identification of novel therapeutic targets and strategies.

Hypoxia-inducible factor signaling in pulmonary hypertension

Pulmonary hypertension (PH) is characterized by pulmonary artery remodeling that can subsequently culminate in right heart failure and premature death. Emerging evidence suggests that hypoxia-inducible factor (HIF) signaling plays a fundamental and pivotal role in the pathogenesis of PH. This Review summarizes the regulation of HIF isoforms and their impact in various PH subtypes, as well as the elaborate conditional and cell-specific knockout mouse studies that brought the role of this pathway to light. We also discuss the current preclinical status of pan- and isoform-selective HIF inhibitors, and propose new research areas that may facilitate HIF isoform-specific inhibition as a novel therapeutic strategy for PH and right heart failure.

Adenosine at the Interphase of Hypoxia and Inflammation in Lung Injury

Hypoxia and inflammation often coincide in pathogenic conditions such as acute respiratory distress syndrome (ARDS) and chronic lung diseases, which are significant contributors to morbidity and mortality for the general population. For example, the recent global outbreak of Coronavirus disease 2019 (COVID-19) has placed viral infection-induced ARDS under the spotlight. Moreover, chronic lung disease ranks the third leading cause of death in the United States. Hypoxia signaling plays a diverse role in both acute and chronic lung inflammation, which could partially be explained by the divergent function of downstream target pathways such as adenosine signaling. Particularly, hypoxia signaling activates adenosine signaling to inhibit the inflammatory response in ARDS, while in chronic lung diseases, it promotes inflammation and tissue injury. In this review, we discuss the role of adenosine at the interphase of hypoxia and inflammation in ARDS and chronic lung diseases, as well as the current strategy for therapeutic targeting of the adenosine signaling pathway.

Smoking load reduction is insufficient to downregulate miR-301b, a lung cancer promoter

Several circulating miRNAs identified in the plasma of smokers have been implicated as promoters of nasopharyngeal and lung carcinoma. To investigate the plasma profile of miRNAs in subjects who reduces the number of smoked cigarettes and who quit after six months. We accompanied 28 individuals enrolled in a Smoking Cessation Program over 6 months. At Baseline, clinical characteristics, co-morbidities, and smoking history were similar among subjects. After 6 months, two groups were defined: who successfully quitted smoking (named "quitters", n = 18, mean age 57 years, 11 male) and who reduced the number of cigarettes smoked (20-90%) but failed to quit smoking (named "smokers", n = 10, mean age 52 years, 3 male). No significant clinical changes were observed between groups at baseline and after a 6-month period, however, quitters showed significant downregulations in seven miRNAs at baseline: miR-17 (- 2.90-fold, p = 0.029), miR-20a (- 3.80-fold, p = 0.021); miR-20b (- 4.71-fold, p = 0.027); miR-30a (- 3.95-fold, p = 0.024); miR-93 (- 3.63-fold, p = 0.022); miR-125a (- 1.70-fold, p = 0.038); and miR-195 (- 5.37-fold, p = 0.002), and after a 6-month period in 6 miRNAs: miR-17 (- 5.30-fold, p = 0.012), miR-20a (- 2.04-fold, p = 0.017), miR-20b (- 5.44-fold, p = 0.017), miR-93 (- 4.00-fold, p = 0.041), miR-101 (- 4.82-fold, p = 0.047) and miR-125b (- 3.65-fold, p = 0.025). Using time comparisons, only quitters had significant downregulation in miR-301b (- 2.29-fold, p = 0.038) after 6-month. Reductions in the number of smoked cigarettes was insufficient to change the plasma profile of miRNA after 6 months. Only quitting smoking (100% reduction) significantly downregulated miR-301b related to hypoxic conditions, promotion of cell proliferation, decreases in apoptosis, cancer development, and progression as increases in radiotherapy and chemotherapy resistance.

Network pharmacology-based study of the molecular mechanisms of Qixuekang in treating COVID-19 during the recovery period

OBJECTIVE

In this research, the analytical method of network pharmacology was used to explore Qixuekang molecular mechanism in treating Coronavirus 2019 (COVID-19) during the recovery period.

METHODS

Traditional Chinese Medicine Systems Pharmacology (TCMSP) database was used to collect the active components and corresponding targets of Qixuekang. Disease targets, related to COVID-19 during the recovery period, were collected from the GeneCards database. Protein-Protein interaction (PPI) network was built by using the String database, and analyzing and using Cytoscape 3.7.0 software to screen out hub genes. GO enrichment and KEGG pathway enrichment analysis were analyzed by R 3.6.1 software.

RESULTS

34 active components of Qixuekang were screened out, and 161 common targets of drug and disease were identified. GO enrichment suggested 141 biologic processes, mainly involving nuclear receptor activity, transcription factor activity, and direct ligand regulated sequence-specific DNA binding. KEGG pathway enrichment suggests 96 signaling pathways, mainly including TNF signaling pathway, IL-17 signal pathway, and C-type lectin receptor signal pathway. The hub genes, screened in the PPI network, were mainly inclusive of CXCL8, CXCL2, CXCL10, ADRA2A, and ADRA2C.

CONCLUSION

Qixuekang has numerous components and targets in treating COVID-19 during the recovery period. It is mainly applied in anti-inflammatory action and regulating immune defense, which may guide clinical trials in the later stage.

Lycium barbarum Polysaccharide Inhibited Hypoxia-Inducible Factor 1 in COPD Patients

Background

Chronic obstructive pulmonary disease (COPD) is a chronic airway inflammatory disease characterized by irreversible airflow obstruction. Pathogenic mechanisms underlying COPD remain largely unknown.

Objective

The current study was designed to explore serum concentration of hypoxia-inducible factor 1α (HIF-1α) in stable COPD patients and the potential effect of Lycium barbarum polysaccharides (LBP) on HIF-1α protein expression.

Methods

Serum HIF-1α was quantified by ELISA in 102 stable COPD patients before and after 2-week orally taken LBP (100 mL/time, twice daily, 5–15 mg/mL). Correlation of serum LBP and lung function (FEV1%) or blood gas (PO₂ and PCO₂) was also analyzed. As a control, 105 healthy subjects were also enrolled into this study.

Results

Serum concentration of HIF-1α was significantly higher in the stable COPD patients (37.34 ± 7.20 pg/mL) than that in the healthy subjects (29.55 ± 9.66 pg/mL, P<0.001). Oral administration of LBP (5 mg/mL, 100 mL, twice daily for 2 weeks) not only relieved COPD symptoms but also significantly reduced serum HIF-1α concentration (36.94 ± 9.23 vs 30.49 ± 6.42 pg/mL, P<0.05). In addition, level of serum HIF-1α concentration was significantly correlated with PCO₂ (r = 0.283, P<0.001), but negatively and significantly correlated with PO₂ (r = −0.490, P=0.005) or FEV1%(r = −0.420, P=0.018).

Conclusion

These findings suggested that activation of HIF-1 signaling pathway may be involved in the pathophysiology of COPD and that stabilization of serum HIF-1α concentration by LBP might benefit the stable COPD patients.

Integrated transcriptomic correlation network analysis identifies COPD molecular determinants

Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous syndrome. Network-based analysis implemented by SWIM software can be exploited to identify key molecular switches - called "switch genes" - for the disease. Genes contributing to common biological processes or defining given cell types are usually co-regulated and co-expressed, forming expression network modules. Consistently, we found that the COPD correlation network built by SWIM consists of three well-characterized modules: one populated by switch genes, all up-regulated in COPD cases and related to the regulation of immune response, inflammatory response, and hypoxia (like TIMP1, HIF1A, SYK, LY96, BLNK and PRDX4); one populated by well-recognized immune signature genes, all up-regulated in COPD cases; one where the GWAS genes AGER and CAVIN1 are the most representative module genes, both down-regulated in COPD cases. Interestingly, 70% of AGER negative interactors are switch genes including PRDX4, whose activation strongly correlates with the activation of known COPD GWAS interactors SERPINE2, CD79A, and POUF2AF1. These results suggest that SWIM analysis can identify key network modules related to complex diseases like COPD.

Molecular Characteristics and Treatment of Endothelial Dysfunction in Patients with COPD: A Review Article

Patients with chronic obstructive pulmonary disease (COPD) show systemic consequences, such as chronic systemic inflammation leading to changes in the airway, airway penetrability, and endothelial function. Endothelial dysfunction is characterized by a list of alterations of endothelium towards reduced vasodilation, proinflammatory state, detachment and apoptosis of endothelial cells, and development of atherosclerosis. COPD-induced endothelial dysfunction is associated with elevated cardiovascular risk. The increment of physical activities such as pulmonary rehabilitation (PR) training have a significant effect on COPD, thus, PR can be an integrative part of COPD treatment. In this narrative review the focus is on the function of endothelial inflammatory mediators [cytokines, chemokines, and cellular proteases] and pulmonary endothelial cells and endothelial dysfunction in COPD as well as the effects of dysfunction of the endothelium may play in COPD-related pulmonary hypertension. The relationship between smoking and endothelial dysfunction is also discussed. The connection between different pulmonary rehabilitation programs, arterial stiffness and pulse wave velocity (PWV) is presented. Endothelial dysfunction is a significant prognostic factor of COPD, which can be characterized by PWV. We discuss future considerations, like training programs, as an important part of the treatment that has a favorable impact on the endothelial function.