Search

Abstract Acute pancreatitis (AP) is a severe and frequently lethal disorder, but the precise mechanisms are not well understood and there is lack of effective drugs. Therefore, our study examined the in vivo intervention effects of genistein and elucidated its mechanism in acute experimental pancreatitis models. We used cerulein or taurocholate to induce acute pancreatitis (AP) in Sprague-Dawley rats with prior genistein treatment. Histological examination of the pancreas was performed and the expression of unfolded protein response (UPR) components and apoptotic mediators like caspase 12 and c-Jun N-terminal protein kinase (JNK) were measured. The amount of apoptosis in pancreatic acinar cells was also determined. Our studies found that the severity of cerulein- or taurocholate-induced AP was rescued by prior genistein treatment. Genistein stimulated the activation of multiple endoplasmic reticulum (ER) stress-related regulators like GRP78, PERK, eIF2α, and upregulated the expression of the apoptotic genes, caspase 12 and CHOP. Moreover, TUNEL assays showed that genistein treatment promoted acinar cell apoptosis. Taken together, we speculated that ER stress-associated apoptotic pathways in AP are induced by genistein, which showed cytoprotective capacity in the exocrine pancreas. These data suggest novel therapeutic strategies that employ genistein in the prevention of AP. Highlights • Genistein attenuated cerulein- or taurocholate-induced AP in vivo. • Genistein induced endoplasmic reticulum stress in rat pancreas. • Genistein promoted apoptosis of pancreatic acinar cells to protect from AP. [ABSTRACT FROM AUTHOR]

Inflamm-aging is a challenging and promising new branch of aging-related research fields that includes areas such as immunosenescence. Increasing evidence indicates that inflamm-aging is intensively associated with many aging diseases, such as Alzheimer's disease, atherosclerosis, heart disease, type II diabetes, and cancer. Mounting studies have focused on the role of inflamm-aging in disease progression and many advances have been made in the last decade. However, the underlying mechanisms by which inflamm-aging affects pathological changes and disease development are still unclear. Here, we review studies of inflamm-aging that explore the concept, pathological features, mechanisms, intervention, and the therapeutic strategies of inflamm-aging in disease progression. [ABSTRACT FROM AUTHOR]

As the global aging process continues to lengthen, aging-related diseases (e.g., chronic obstructive pulmonary disease (COPD), heart failure) continue to plague the elderly population. Aging is a complex biological process involving multiple tissues and organs and is involved in the development and progression of multiple aging-related diseases. At the same time, some of these aging-related diseases are often accompanied by hypoxia, chronic inflammation, oxidative stress, and the increased secretion of the senescence-associated secretory phenotype (SASP). Hypoxia seems to play an important role in the process of inflammation and aging, but is often neglected in advanced clinical research studies. Therefore, we have attempted to elucidate the role played by different degrees and types of hypoxia in aging and aging-related diseases and their possible pathways, and propose rational treatment options based on such mechanisms for reference. [ABSTRACT FROM AUTHOR]

The aim was to determine whether lipid molecules can be used as potential biomarkers for idiopathic pulmonary arterial hypertension (IPAH), providing important reference value for early diagnosis and treatment. Liquid chromatography–mass spectrometry-based lipidomic assays allow for the simultaneous detection of a large number of lipids. In this study, lipid profiling was performed on plasma samples from 69 IPAH patients and 30 healthy controls to compare the levels of lipid molecules in the 2 groups of patients, and Cox regression analysis was used to identify meaningful metrics, along with receiver operator characteristic curves to assess the ability of the lipid molecules to predict the risk of disease in patients. Among the 14 lipid subclasses tested, 12 lipid levels were significantly higher in IPAH patients than in healthy controls. Free fatty acids (FFA) and monoacylglycerol (MAG) were significantly different between IPAH patients and healthy controls. Logistic regression analysis showed that FFA (OR: 1.239, 95%CI: 1.101, 1.394, p < 0.0001) and MAG (OR: 3.711, 95%CI: 2.214, 6.221, p < 0.001) were independent predictors of IPAH development. Among the lipid subclasses, FFA and MAG have potential as biomarkers for predicting the pathogenesis of IPAH, which may improve the early diagnosis of IPAH. [ABSTRACT FROM AUTHOR]

Background: Our previous study showed that circular RNA-gamma-secretase-activating protein (circGSAP) was down-regulated in pulmonary microvascular endothelial cells (PMECs) in response to hypoxia, and regulated the cell cycle of PMECs via miR-942-5p sponge in pulmonary hypertension (PH). However, the mechanism whether circGSAP affects the dysfunction of PEMCs through other microRNAs (miRNAs) remains largely unknown. Therefore, we aimed to demonstrate the underlying mechanisms of circGSAP regulating PMECs dysfunction by absorbing other miRNAs to regulate target genes in idiopathic pulmonary arterial hypertension (IPAH).Methods: Quantitative real-time polymerase chain reaction, immunofluorescence staining, Cell Counting Kit-8, Calcein-AM/PI staining, Transwell assay, dual-luciferase reporter assay, and ELISA were used to elucidate the roles of circGSAP.Results: Here we showed that plasma circGSAP levels were significantly decreased in patients with IPAH and associated with poor outcomes. In vivo, circGSAP overexpression improved survival, and alleviated pulmonary vascular remodeling of monocrotaline-induced PH (MCT-PH) rats. In vitro, circGSAP overexpression inhibited hypoxia-induced PMECs proliferation, migration and increased mortality by absorbing miR-27a-3p. BMPR2 was identified as a miR-27a-3p target gene. BMPR2 silencing ameliorated the effect of the miR-27a-3p inhibitor on PMECs proliferation,migration and mortality. The levels of BMPR2 were upregulated in circGSAP-overexpressed PMECs and lung tissues of MCT-PH rats.Conclusion: Our findings demonstrated that circGSAP alleviated the dysfunction of PMECs via the increase of BMPR2 by competitively binding with miR-27a-3p, and mitigated pulmonary vascular remodeling of MCT-PH rats, providing potential therapeutic strategies for IPAH. [ABSTRACT FROM AUTHOR]

Pulmonary arterial hypertension (PAH) is a rare and chronic lung vasculature disease characterised by pulmonary vasculature remodelling, including abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) and dysfunctional endothelial cells (ECs). Remodelling of the pulmonary vasculature occurs from maturity to senescence, and it has become apparent that cellular senescence plays a central role in the pathogenesis of various degenerative vascular diseases and pulmonary pathologies. Cellular senescence represents a state of stable proliferative arrest accompanied by the senescence‐associated secretory phenotype (SASP), which entails the copious secretion of proinflammatory signals in the tissue microenvironment. Evidence shows that in PAH patients, higher levels of cytokines, chemokines and inflammatory mediators can be detected and correlate with clinical outcome. Moreover, senescent cells accrue with age in epithelial, endothelial, fibroblastic and immunological compartments within human lungs, and evidence has shown that ECs and PASMCs in lungs from patients with chronic obstructive pulmonary disease were characterised by a higher number of senescent cells. However, there is little evidence uncovering the molecular pulmonary vasculature senescence in PAH. Herein, we review the cellular senescence in pulmonary vascular remodelling, and emphasise its importance in PAH. We further introduce some signalling pathways which might be involved in vasculature senescence and PAH, with the intent to discuss the possibility of the PAH therapy via targeting cellular senescence and reduce PAH progression and mortality. [ABSTRACT FROM AUTHOR]

The age‐related pro‐inflammatory state, discovered and called 'inflammaging' by Franceschi et al. (2000) plays an important role in the pathogenesis of age‐related chronic diseases. A substantial body of data established that inflammaging is accompanied by a '2‐fold to 4‐fold' increase in plasma levels of pro‐inflammatory mediators in healthy elderly people, when compared to the healthy adult population. This review focuses on the pre‐inflammaging phase, here we reported as 'cold‐inflammaging', a state where plasma levels of cytokines are slightly increased, but below the lower limit of 2‐fold increase established for inflammaging. Slightly altered cytokine levels by innate immunity are known to be associated with homeostasis imbalances, this functional pleiotropy of cytokines as signal transducers, have a physiological counterpart, representing an adaptive process aimed at restoring (or achieving a new) homeostatic stability. If a dyshomeostatic state persists, the cytokine response by innate immunity increases and becomes a driver of inflammaging. A scenario where cytokines are characterised as major players in homeostasis imbalances at the beginning (cold‐inflammaging) and then in chronic low‐grade pro‐inflammatory‐state (inflammaging). Other important drivers of inflammaging are cellular senescence with its senescence‐associated secretory phenotype, the altered gut microbiota, and the age‐related dysregulation in the production of endogenous molecular waste (Garb‐aging). The main purpose of this review being to thoroughly investigate each step of the pathway from cold‐inflammaging to overt‐inflammaging, because aging, cold‐inflammaging, overt‐inflammaging and the pathogenesis of age‐related diseases have been shown to share some established basic pillars of geroscience that largely converge on inflammaging. [ABSTRACT FROM AUTHOR]

Increased Aβ clearance from brain is essential for restoring the pathological manifestation of Alzheimer's disease (AD) and attenuating the cognitive disorder. The blood-brain barrier (BBB) plays a critical role in maintaining homeostasis of the brain, and transporters e.g. P-glycoprotein (P-gp) are essential for Aβ clearance from the brain. In addition, the Wnt/β-catenin signaling pathway contributes to BBB formation, induction and maturation, and induces BBB function. Dysfunctional Wnt/β-catenin signaling in the BBB reveals the importance of this pathway, since this contributes to the neurodegeneration characteristic of AD. Based on the above evidence, we propose that targeting the canonical Wnt signaling pathway could be promising therapeutic approach for treatment of AD. [ABSTRACT FROM AUTHOR]

Highlights: [•] Icaritin was a novel antidepressant. [•] It restored social defeat-induced impairment of glucocorticoid sensitivity. [•] These effects are attributed to normalization of the GR function. [ABSTRACT FROM AUTHOR]

Particulate matter (PM2.5) and cigarette smoke exposure are leading factors contributing to various diseases, especially respiratory diseases. The purpose of this research was to study the effects of PM2.5 and cigarette smoke on glycerol kinase 5 (GK5) expression and the possible mechanisms by which GK5 participates in lipid droplet (LD) synthesis in alveolar epithelial A549 cells. Real‐time polymerase chain reaction (RT‐PCR) and western blotting have been used for the detection of messenger RNA (mRNA) and protein expression respectively. GK5 overexpressing cells were established by lentivirus transfection, whereby lentiviral vectors deliver the gene into chromosomes, allowing stable expression. Affymetrix microarray analysis, a widely used tool for measuring genome‐wide gene expression, has been used to explore differential gene expression profiles. A549 cells stimulated with PM2.5 and cigarette smoke extract (CSE) showed elevated GK5 expression in a dose‐dependent manner. Transmission electron microscopy and oil red O staining were used to observe LDs in cells. Further, GK5 overexpressing cells showed increased LDs and upregulation of genes and proteins related to lipogenesis and lipid transportation. Affymetrix microarray analysis revealed that GK5 overexpression resulted in the differential expression of more than 109 genes, which were mainly involved in the regulation of cell death, cell survival, cellular movement and migration, and those involved in cellular growth and proliferation pathways. Overall, this study demonstrates that GK5 is upregulated during PM2.5 and cigarette smoke exposure and induces LD synthesis. [ABSTRACT FROM AUTHOR]

Previous studies on the longevity effect of pyrroloquinoline quinine (PQQ) on nematode worms have revealed that PQQ can enhance the antioxidant capacity of nematode worms, thus extending the lifespan of the worms. The induction and development of cellular senescence are closely connected with inflammatory reactions. The aim of this study was to determine the effect of PQQ and ageing factors on senescent cells. To this end, we cultivated human embryonic lung fibroblasts in nutrient solution with or without tumour necrosis factor‐alpha (TNF‐α) to establish an inflammaging model in vitro. The cells were preincubated with or without PQQ to determine if PQQ had any anti‐inflammaging effect. More senescent cells were detected with the addition of TNF‐α than without (P < .01). The ratio of senescent cells to non‐senescent cells in the TNF‐α group was greater than that in the control group (P < .01). When cells were preincubated with PQQ prior to TNF‐α treatment, there were fewer senescent cells than those in the control group, which was not pretreated with PQQ (P < .05). The same tendency was noted with regard to p21, p16, and Jagged1. In summary, we used TNF‐α, a well‐known pro‐inflammatory cytokine associated with inflammaging, to establish an in vitro inflammaging model and provided evidence that PQQ delays TNF‐α –induced cellular senescence and has anti‐inflammaging properties. [ABSTRACT FROM AUTHOR]

Both reactive oxygen species (ROS) from redox-biology and pro-inflammatory cytokines from innate immunity/and other sources, in addition to their role in redox-biology, and in defense and repair, have long been regarded as potentially harmful factors associated with oxidative stress and inflammatory states. However, their important physiological functions as signaling molecules have been demonstrated to be of importance, also in Geroscience, particularly when ROS are at balanced basal levels (redox-biology) and pro-inflammatory cytokines are at very low levels (cold-inflammaging). Under these conditions, both of these components (alone or in combination) may act as signaling/response molecules involved in regulating/maintaining or restoring adaptive homeostasis during aging, particularly in the early phases of even very-mild non-damaging internal or external environmental stimuli that could nevertheless elicit low-grade warnings-signals for homeostatic stability. If signals potentially perturbing homeostasis persist, the levels of ROS and pro-inflammatory mediators increase resulting in a switch from adaptive to maladaptive responses which may lead to oxidative stress and overt-inflammaging (or even to an overt inflammatory state), thus paving the way to the risks of aging-related diseases (ARDs). Conversely, upon adaptive-responses, low-levels of ROS and very-low-levels of pro-inflammatory-cytokines, alone or in combination, can result in an amplified capacity to prevent or slow-down overt-inflammaging (2-fold to 4-fold increase of pro-inflammatory cytokines) thus maintaining or restoring homeostasis. Therefore, these signaling molecules may also have the sequential incremental potential to prevent or slow the subsequent decline of adaptive homeostasis that will occur later in the lifespan. These scenarios may lead us to conceive of, and conceptualize, both these molecules and their basal-low levels, as well as their dynamics and the time-course of responses, as 'potential important pillars of adaptive-homeostasis in aging' since the earliest phases of the occurrence of any even very- mild environmental potential imbalance. • ROS and pro-inflammatory cytokines as molecules that cause damage (e.g., oxidative stress and inflammaging), but to appreciate their role in regulating signaling pathways that affect normal physiological and biological responses. • The effects of these two pathways: (a) basal-low levels ROS and (b) very low levels of pro-inflammatory mediators, can, working alone or in concert, prevent and/or intervene on even minor homeostatic imbalances since the very early phases, thus initiating signal transductions for the regulation maintenance or restoration of adaptive homeostasis in aging. • "Basic Pillars of adaptive-homeostasis in ageing", whose combination can also prevent or slow-down the transition from cold-inflammaging tot overt-inflammaging. [ABSTRACT FROM AUTHOR]

Neuropathic pain (NPP) is intolerable, persistent, and specific type of long-term pain. It is considered to be a direct consequence of pathological changes affecting the somatosensory system and can be debilitating for affected patients. Despite recent progress and growing interest in understanding the pathogenesis of the disease, NPP still presents a major diagnostic and therapeutic challenge. High mobility group box 1 (HMGB1) mediates inflammatory and immune reactions in nervous system and emerging evidence reveals that HMGB1 plays an essential role in neuroinflammation through receptors such as Toll-like receptors (TLR), receptor for advanced glycation end products (RAGE), C-X-X motif chemokines receptor 4 (CXCR4), and N-methyl-D-aspartate (NMDA) receptor. In this review, we present evidence from studies that address the role of HMGB1 in NPP. First, we review studies aimed at determining the role of HMGB1 in NPP and discuss the possible mechanisms underlying HMGB1-mediated NPP progression where receptors for HMGB1 are involved. Then we review studies that address HMGB1 as a potential therapeutic target for NPP. [ABSTRACT FROM AUTHOR]

Studies have shown that misfolded proteins and endoplasmic reticulum (ER) stress play pivotal roles in the progression of Alzheimer's disease (AD). It has also been reported that ER stress is considered to be a common mediator of apoptosis in neurodegenerative disorders like AD. However, the precise mechanisms leading to neuronal cell death caused by ER stress in AD remain unclear. Hsp70, the major inducible form of the heat shock protein family, functions at the level of chaperone-mediated protein folding. Enhanced expression of Hsp70 suppresses the neurotoxicity caused by protein misfolding. EGb761, an accepted traditional Chinese medicine used to treat AD, was used here to examine the molecular mechanism underlying its protective effect on ER stress and Hsp70. Our study shows that pretreatment with EGb761 overcomes the neurotoxicity of the Aβ 1-42 oligomer by increasing Hsp70, Grp78, IRE1α and pAkt expression in a dose-dependent manner and significantly decreases cell apoptosis-related protein expression. Our findings suggest that the neuroprotective effect of EGb761 is related to ER stress activation and increased Hsp70 expression, and subsequent activation of Akt. However, the effect of EGb761 on these processes is not direct. [ABSTRACT FROM AUTHOR]

Accumulating evidence indicates that abnormal deposition of amyloid-β (Ab) peptide in the brain is responsible for endothelial cell damage and consequently leads to blood-brain barrier (BBB) leakage. However, the mechanisms underlying BBB disruption are not well described. We employed an monolayer BBB model comprising bEnd.3 cell and found that BBB leakage was induced by treatment with Aβ1-42, and the levels of tight junction (TJ) scaffold proteins (ZO-1, Claudin-5, and Occludin) were decreased. Through comparisons of the effects of the different components of Aβ1-42, including monomer (Aβ1-42-Mono), oligomer (Aβ1-42-Oligo), and fibril (Aβ1-42-Fibril), our data confirmed that Aβ1-42-Oligo is likely to be the most important damage factor that results in TJ damage and BBB leakage in Alzheimer's disease. We found that the incubation of bEnd.3 cells with Aβ1-42 significantly up-regulated the level of receptor for advanced glycation end-products (RAGE). Co-incubation of a polyclonal antibody to RAGE and Aβ1-42-Oligo in bEnd.3 cells blocked RAGE suppression of Aβ1-42-Oligo-induced alterations in TJ scaffold proteins and reversed Aβ1-42-Oligoinduced up-regulation of RAGE, matrix metalloproteinase (MMP)-2, and MMP-9. Furthermore, we found that these effects induced by Aβ1-42-Oligo treatment were effectively suppressed by knockdown of RAGE using small interfering RNA (siRNA) transfection. We also found that GM 6001, a broad-spectrum MMP inhibitor, partially reversed the Aβ1-42-Oligo-induced inhibitor effects in bEnd.3 cells. Thus, these results suggested that RAGE played an important role in Abinduced BBB leakage and alterations of TJ scaffold proteins, through a mechanism that involved up-regulation of MMP-2 and MMP-9. [ABSTRACT FROM AUTHOR]

Neural stem cells (NSCs) harbor the potential to differentiate into neurons, astrocytes, and oligodendrocytes under normal conditions and/or in response to tissue damage. NSCs open a new way of treatment of the injured central nervous system and neurodegenerative disorders. Thus far, few drugs have been developed for controlling NSC functions. Here, the effect as well as mechanism of oleanolic acid (OA), a pentacyclic triterpenoid, on NSC function was investigated. We found OA significantly inhibited neurosphere formation in a dose-dependent manner and achieved a maximum effect at 10 nM. OA also reduced 5-ethynyl-2′-deoxyuridine (EdU) incorporation into NSCs, which was indicative of inhibited NSC proliferation. Western blotting analysis revealed the protein levels of neuron-specific marker tubulin-βIII (TuJ1) and Mash1 were increased whilst the astrocyte-specific marker glial fibrillary acidic protein (GFAP) decreased. Immunofluorescence analysis showed OA significantly elevated the percentage of TuJ1-positive cells and reduced GFAP-positive cells. Using DNA microarray analysis, 183 genes were differentially regulated by OA. Through transcription factor binding site analyses of the upstream regulatory sequences of these genes, 87 genes were predicted to share a common motif for Nkx-2.5 binding. Finally, small interfering RNA (siRNA) methodology was used to silence Nkx-2.5 expression and found silence of Nkx-2.5 alone did not change the expression of TuJ-1 and the percentage of TuJ-1-positive cells. But in combination of OA treatment and silence of Nkx-2.5, most effects of OA on NSCs were abolished. These results indicated that OA is an effective inducer for NSCs differentiation into neurons at least partially by Nkx-2.5-dependent mechanism. [ABSTRACT FROM AUTHOR]

Neurodegeneration is the umbrella term for the progressive loss of structure or function of neurons. Incurable neurodegenerative disorders such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) show dramatic rising trends particularly in the advanced age groups. However, the underlying mechanisms are not yet fully elucidated, and to date there are no biomarkers for early detection or effective treatments for the underlying causes of these diseases. Furthermore, due to species variation and differences between animal models (e.g., mouse transgenic and knockout models) of neurodegenerative diseases, substantial debate focuses on whether animal and cell culture disease models can correctly model the condition in human patients. In 2006, Yamanaka of Kyoto University first demonstrated a novel approach for the preparation of induced pluripotent stem cells (iPSCs), which displayed similar pluripotency potential to embryonic stem cells (ESCs). Currently, iPSCs studies are permeating many sectors of disease research. Patient sample-derived iPSCs can be used to construct patient-specific disease models to elucidate the pathogenic mechanisms of disease development and to test new therapeutic strategies. Accordingly, the present review will focus on recent progress in iPSC research in the modeling of neurodegenerative disorders and in the development of novel therapeutic options. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the effect of icariin (ICA) on cardiac aging through its effects on the SIRT6 enzyme and on the NF-κB pathway. Investigating the effect of ICA on the enzymatic activity of histone deacetylase SIRT6 revealed a concentration of 10−8 mol/L ICA had a maximum activating effect on histone deacetylase SIRT6 enzymatic activity. Western analysis showed that ICA upregulated SIRT6 protein expression and downregulated NF-κB (p65) protein expression in animal tissues and cell models. ICA upregulated the expression of SIRT6 and had an inhibitory effect on NF-κB inflammatory signaling pathways as shown by decreasing mRNA levels of the NF-κB downstream target genes TNF-α, ICAM-1, IL-2, and IL-6. Those effects were mediated directly or indirectly by SIRT6. We provided evidence that inflammaging may involve a novel link between the effects of ICA on SIRT6 (a regulator of aging) and NF-κB (a regulator of inflammation). [ABSTRACT FROM AUTHOR]

Highlights: [•] Icaritin attenuates cigarette smoke-mediated oxidative stress. [•] Icaritin activates PI3K-AKT and Nrf2 signal pathways. [•] Inactivation of PI3k and Nrf2 reserves icaritin-induced GCL upregulation. [Copyright &y& Elsevier]

Diabetes mellitus increases the risk of dementia, and evidence suggests hyperglycemia is a key contributor to neurodegeneration. However, our understanding of diabetes-associated cognitive decline, an important complication of diabetes mellitus, is lacking and the underlying mechanism is unclear. Blood brain barrier (BBB) breakdown is a possible cause of dementia in diabetes mellitus and Alzheimer's disease. Accumulating evidence shows BBB dysfunction caused by hyperglycemia contributes to cognitive decline. A specific type of inflammatory programmed cell death, called pyroptosis, has potential as a therapeutic target for BBB-associated diseases. Potential inducers of pyroptosis include inflammasomes such as NLRP3, whose activation relies on damage-associated molecular patterns. High mobility group box 1 (HMGB1) is a highly conserved, ubiquitous protein found in most cell types, and acts as a damage-associated molecular pattern when released from the nucleus. We propose that HMGB1 influences vascular inflammation by activating the NLRP3 inflammasome and thereby initiating pyroptosis in vascular cells. Moreover, HMGB1 plays a pivotal role in the pathogenesis of diabetes mellitus and diabetic complications. Here, we review the role of HMGB1 in BBB dysfunction induced by hyperglycemia and propose that HMGB1 is a promising therapeutic target for countering diabetes-associated cognitive decline. [Display omitted] • Diabetes mellitus makes a contribution to blood brain barrier breakdown. • Blood brain barrier disturbances in diabetes could be the possible link between dementia and diabetes. • Pyroptosis contributes to hyperglycemia induced BBB breakdown. • HMGB1 plays an important role in pyroptosis of injured blood brain barrier via activating NLRP3 inflammasome. [ABSTRACT FROM AUTHOR]

Particulate matter (PM)-induced airway inflammation contributes to the development and exacerbation of chronic airway diseases. Circular RNA (circRNA) is a new class of non-coding RNA that participates in gene regulation in various respiratory diseases, but the regulatory role of circRNA in PM-induced airway inflammation has not been fully elucidated. In this study, we performed the human circRNA microarray to reveal differentially expressed circRNAs in PM-induced human bronchial epithelial cells (HBECs). A total of 176 upregulated and 15 downregulated circRNAs were identified. Of these, a new circRNA termed circTXNRD1 was upregulated by PM exposure in a dose- and time-dependent manner. Knockdown of circTXNRD1 significantly attenuated PM-induced expression of proinflammatory cytokine interleukin 6 (IL-6). CircRNA pull-down, dual-luciferase reporter assay and fluorescence in situ hybridization showed that circTXNRD1 acted as an endogenous sponge to decrease miR-892a levels in HBECs. Downregulation of miR-892a could increase cyclooxygenase-2 (COX-2) expression and eventually promote IL-6 secretion in PM-induced HBECs. Taken together, our findings reveal circTXNRD1 as a novel inflammatory mediator in PM-induced inflammation in HBECs via regulating miR-892a/COX-2 axis. These results provide new insight into the biological mechanism underlying PM-induced inflammation in chronic airway diseases. [Display omitted] • The differential circRNAs expression profile was identified in PM-exposed HBECs. • The circTXNRD1 was significantly upregulated by PM in HBECs. • The circTXNRD1 promoted PM-induced inflammation via miR-892a/COX-2 axis in HBECs. [ABSTRACT FROM AUTHOR]

The coronavirus disease 2019 (COVID-19) is a new infectious respiratory disease, which has caused a pandemic that has become the world's leading public health emergency, threatening people of all ages worldwide, especially the elderly. Complications of COVID-19 are closely related to an upregulation of the inflammatory response revealed by the pro-inflammatory profile of plasma cytokines (to the point of causing a cytokine storm), which is also a contributing cause of the associated coagulation disorders with venous and arterial thromboembolisms, causing multiple organ dysfunction and failure. In severe fulminant cases of COVID-19, there is an activation of coagulation and consumption of clotting factors leading to a deadly disseminated intravascular coagulation (DIC). It is well established that human immune response changes with age, and also that the pro-inflammatory profile of plasma cytokines is upregulated in both healthy and diseased elderly people. In fact, normal aging is known to be associated with a subclinical, sterile, low-grade, systemic pro-inflammatory state linked to the chronic activation of the innate immune system, a phenomenon known as "inflammaging". Inflammaging may play a role as a condition contributing to the co-occurrence of the severe hyper-inflammatory state (cytokine storm) during COVID-19, and also in other severe infections (sepsis) in older people. Moreover, we must consider the impact of inflammation on coagulation due to the crosstalk between inflammation and coagulation. The systemic inflammatory state and coagulation disorders are closely related, a phenomenon that here we call "coagul-aging" (Giunta S.). In this review, we discuss the various degrees of inflammation in older adults after being infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the adverse effects of aging on the inflammatory response and coagulation system. It is important to note that although there is no gender difference in susceptibility to COVID-19 infection, however, due to differences in angiotensin-converting enzyme 2 (ACE2) expression, innate immunity, and comorbidities, older men exhibit more severe disease and higher mortality than older women. There are currently no FDA-approved specific antiviral drugs that can be used against the virus. Therapies used in patients with COVID-19 consist of remdesivir, dexamethasone, low-molecular-weight heparin, in addition to monoclonal antibodies against the spike protein of SARS-CoV-2 in the early phase of the disease. Future pharmacological research should also consider targeting the possible role of the underlying scenario of inflammaging in healthy older people to prevent or mitigate disease complications. It is worth mentioning that some specific cytokine antagonists and traditional Chinese medicine preparations can reduce the elderly's inflammatory state. • The elderly have seriously been threatened in this COVID-19 epidemic, especially older men. • Inflammaging and coagul-aging are important factors for the poor prognosis of the elderly. • Some specific cytokine antagonists and traditional Chinese medicine preparations can alleviate the inflammatory state. [ABSTRACT FROM AUTHOR]

Circular RNAs (CircRNAs), as a new class of non-coding RNA molecules that, unlike linear RNAs, have covalently closed loop structures from the ligation of exons, introns, or both. CircRNAs are widely expressed in various organisms in a specie-, tissue-, disease- and developmental stage-specific manner, and have been demonstrated to play a vital role in the pathogenesis and progression of human diseases. An increasing number of recent studies has revealed that circRNAs are intensively associated with different respiratory diseases, including lung cancer, acute respiratory distress syndrome, pulmonary hypertension, pulmonary tuberculosis, and silicosis. However, to the best of our knowledge, there has been no systematic review of studies on the role of circRNAs in respiratory diseases. In this review, we elaborate on the biogenesis, functions, and identification of circRNAs and focus particularly on the potential implications of circRNAs in respiratory diseases. [ABSTRACT FROM AUTHOR]