Circadian clock dysfunction of epithelial cells in pulmonary diseases

NR1D1 mitigates IL-17a-induced small airway remodeling in biomass smoke-induced COPD

INTRODUCTION

Biomass smoke (BS) exposure is a critical environmental risk factor for Chronic Obstructive Pulmonary Disease (COPD). In this study, mechanisms of biomass smoke (BS)-induced small airway disease are explored, with a focus on the roles of Interleukin-17a (IL-17a) and Nuclear Receptor Subfamily 1 Group D Member 1 (NR1D1).

METHODS

This study included 20 BS exposure COPD (BS-COPD) patients and 13 controls, who underwent chest high-resolution computed tomography (HRCT) scans to assess emphysema and small airway disease. The control group was divided into a low- and high BS exposure control group. Serum IL-17a levels were measured. Wild-type and IL-17a-/- B6/C57 mice were exposed to wood smoke to establish a COPD model in mice. Airway pathology was evaluated by histological analysis. The effects of IL-17a and NR1D1 on cell proliferation of BEAS-2b cells exposed to wood smoke particulate matter 2.5 were assessed in vitro using flow cytometry and Western blotting.

RESULTS

HRCT revealed significantly higher small airway disease and emphysema in BS-COPD patients compared to controls (p < 0.01). Small airway disease exhibited the strongest negative correlation with FEV1%predicted (r = -0.61, p = 0.004). High-exposure control group showed significant BS Index correlations with small airway disease (r = 0.81, p = 0.049) and emphysema (r = 0.87, p = 0.025). Serum IL-17a levels correlated with small airway disease in BS-COPD (r = 0.48, p = 0.033). The mouse model demonstrated higher airway wall thickness and small airway disease in IL-17a-/- mice exposed to wood smoke. In vitro, IL-17a promoted BEAS-2b cell proliferation, an effect enhanced by NR1D1 downregulation.

CONCLUSIONS

BS exposure drives emphysema and small airway disease in non-COPD individuals. NR1D1 downregulation exacerbates IL-17a-mediated remodeling in vitro, suggesting therapeutic potential.

TRIAL REGISTRATION

ChiCTR-OOC-16008692.

A New Frontier in Cystic Fibrosis Pathophysiology: How and When Clock Genes Can Affect the Inflammatory/Immune Response in a Genetic Disease Model

Cystic fibrosis (CF) is a monogenic syndrome caused by variants in the CF Transmembrane Conductance Regulator (CFTR) gene, affecting various organ and systems, in particular the lung, pancreas, sweat glands, liver, gastrointestinal tract, vas deferens, and vascular system. While for some organs, e.g., the pancreas, a strict genotype-phenotype occurs, others, such as the lung, display a different pathophysiologic outcome in the presence of the same mutational asset, arguing for genetic and environmental modifiers influencing severity and clinical trajectory. CFTR variants trigger a pathophysiological cascade of events responsible for chronic inflammatory responses, many aspects of which, especially related to immunity, are not ascertained yet. Although clock genes expression and function are known modulators of the innate and adaptive immunity, their involvement in CF has been only observed in relation to sleep abnormalities. The aim of this review is to present current evidence on the clock genes role in immune-inflammatory responses at the lung level. While information on this topic is known in other chronic airway diseases (chronic obstructive pulmonary disease and asthma), CF lung disease (CFLD) is lacking in this knowledge. We will present the bidirectional effect between clock genes and inflammatory factors that could possibly be implicated in the CFLD. It must be stressed that besides sleep disturbance and its mechanisms, there are not studies directly addressing the exact nature of clock genes' involvement in inflammation and immunity in CF, pointing out the directions of new and deepened studies in this monogenic affection. Importantly, clock genes have been found to be druggable by means of genetic tools or pharmacological agents, and this could have therapeutic implications in CFLD.

Circadian Rhythm Alteration of the Core Clock Genes and the Lipid Metabolism Genes Induced by High-Fat Diet (HFD) in the Liver Tissue of the Chinese Soft-Shelled Turtle (Trionyx sinensis)

Physiology disorders of the liver, as it is an important tissue in lipid metabolism, can cause fatty liver disease. The mechanism might be regulated by 17 circadian clock genes and 18 fat metabolism genes, together with a high-fat diet (HFD). Due to their rich nutritional and medicinal value, Chinese soft-shelled turtles (Trionyx sinensis) are very popular among the Chinese people. In the study, we aimed to investigate the influence of an HFD on the daily expression of both the core clock genes and the lipid metabolism genes in the liver tissue of the turtles. The two diets were formulated with 7.98% lipid (the CON group) and 13.86% lipid (the HFD group) to feed 180 juvenile turtles, which were randomly divided into two groups with three replicates per group and 30 turtles in each replicate for six weeks, and the diet experiment was administrated with a photophase regimen of a 24 h light/dark (12L:12D) cycle. At the end of the experiment, the liver tissue samples were collected from nine turtles per group every 3 h (zeitgeber time: ZT 0, 3, 6, 9, 12, 15, 18, 21 and 24) for 24 h to investigate the daily expression and correlation analysis of these genes. The results showed that 11 core clock genes [i.e., circadian locomotor output cycles kaput (Clock), brain and muscle arnt-like protein 1 and 2 (Bmal1/2), timeless (Tim), cryptochrome 1 (Cry2), period2 (Per2), nuclear factor IL-3 gene (Nfil3), nuclear receptor subfamily 1, treatment D, member 1 and 2 (Nr1d1/2) and retinoic acid related orphan receptor α/β/γ β and γ (Rorβ/γ)] exhibited circadian oscillation, but 6 genes did not, including neuronal PAS domain protein 2 (Npas2), Per1, Cry1, basic helix-loop-helix family, member E40 (Bhlhe40), Rorα and D-binding protein (Dbp), and 16 lipid metabolism genes including fatty acid synthase (Fas), diacylglycerol acyltransferase 1 (Dgat1), 3-hydroxy-3-methylglutaryl-CoA reductase (Hmgcr), Low-density lipoprotein receptor-related protein 1-like (Ldlr1), Lipin 1 (Lipin1), Carnitine palmitoyltransferase 1A (Cpt1a), Peroxisome proliferator activation receptor α, β and γ (Pparα/β/γ), Sirtuin 1 (Sirt1), Apoa (Apoa1), Apolipoprotein B (Apob), Pyruvate Dehydrogenase kinase 4 (Pdk4), Acyl-CoA synthase long-chain1 (Acsl1), Liver X receptors α (Lxrα) and Retinoid X receptor, α (Rxra) also demonstrated circadian oscillations, but 2 genes did not, Scd and Acaca, in the liver tissues of the CON group. However, in the HFD group, the circadian rhythms' expressional patterns were disrupted for the eight core clock genes, Clock, Cry2, Per2, Nfil3, Nr1d1/2 and Rorβ/γ, and the peak expression of Bmal1/2 and Tim showed delayed or advanced phases. Furthermore, four genes (Cry1, Per1, Dbp and Rorα) displayed no diurnal rhythm in the CON group; instead, significant circadian rhythms appeared in the HFD group. Meanwhile, the HFD disrupted the circadian rhythm expressions of seven fat metabolism genes (Fas, Cpt1a, Sirt1, Apoa1, Apob, Pdk4 and Acsl1). Meanwhile, the other nine genes in the HFD group also showed advanced or delayed expression peaks compared to the CON group. Most importantly of all, there were remarkably positive or negative correlations between the core clock genes and the lipid metabolism genes, and their correlation relationships were altered by the HFD. To sum up, circadian rhythm alterations of the core clock genes and the lipid metabolism genes were induced by the high-fat diet (HFD) in the liver tissues of T. sinensis. This result provides experimental and theoretical data for the mass breeding and production of T. sinensis in our country.

Recent advances in circadian-regulated pharmacokinetics and its implications for chronotherapy

Dependence of pharmacokinetics and drug effects (efficacy and toxicity) on dosing time has long been recognized. However, significant progress has only recently been made in our understanding of circadian rhythms and their regulation on drug pharmacokinetics, efficacy and toxicity. This review will cover the relevant literature and a series of publications from our work summarizing the effects of circadian rhythms on drug pharmacokinetics, and propose that the influence of circadian rhythms on pharmacokinetics are ultimately translated into therapeutic effects and side effects of drugs. Evidence suggests that daily rhythmicity in expression of drug-metabolizing enzymes and transporters necessary for drug ADME (absorption, distribution, metabolism and excretion) are key factors determining circadian pharmacokinetics. Newly discovered mechanisms for circadian control of the enzymes and transporters are covered. We also discuss how the rhythms of drug-processing proteins are translated into circadian pharmacokinetics and drug chronoefficacy/chronotoxicity, which has direct implications for chronotherapy. More importantly, we will present perspectives on the challenges that are still needed for a breakthrough in translational research. In addition, knowledge of the circadian influence on drug disposition has provided new possibilities for novel pharmacological strategies. Careful application of pharmacokinetics-based chronotherapy strategies can improve efficacy and reduce toxicity. Circadian rhythm-mediated metabolic and transport strategies can also be implemented to design drugs.

Expanding the arsenal against pulmonary diseases using surface-functionalized polymeric micelles: breakthroughs and bottlenecks

Pulmonary diseases such as lung cancer, asthma and tuberculosis have remained one of the common challenges globally. Polymeric micelles (PMs) have emerged as an effective technique for achieving targeted drug delivery for a local as well as a systemic effect. These PMs encapsulate and protect hydrophobic drugs, increase pulmonary targeting, decrease side effects and enhance drug efficacy through the inhalation route. In the current review, emphasis has been placed on the different barriers encountered by the drugs given via the pulmonary route and the mechanism of PMs in achieving drug targeting. The applications of PMs in different pulmonary diseases have also been discussed in detail.