Hydroquinone Exposure Worsens Rheumatoid Arthritis through the Activation of the Aryl Hydrocarbon Receptor and Interleukin-17 Pathways

Hydroquinone impairs trophoblast migration and invasion via AHR-twist-IFITM1 axis

INTRODUCTION

Embryo implantation is a tightly regulated process, critical for a successful pregnancy. After attachment of the blastocyst to the surface epithelium of the endometrium trophoblast migrate from the trophectoderm and invade into the stromal component of endometrium. Alterations on either process will lead to implantation failure or miscarriage. Volatile organic compounds (VOCs) such as benzene induce pregnancy complications, including preterm birth and miscarriages. The mechanism of this effect is unknown. The objective of this study was to elucidate the impact of benzene metabolite, Hydroquinone, on trophoblast function. We tested the hypothesis that Hydroquinone activates the Aryl hydrocarbon receptor (AhR) pathway modulating trophoblast migration and invasion.

METHODS

First-trimester trophoblast cells (Sw.71) were treated with hydroquinone (6 and 25 μM). Trophoblast migration and invasion was evaluated using a 3D invasion/migration model. Gene expression was quantified by q-PCR and Western blot analysis.

RESULTS

Hydroquinone impairs trophoblast migration and invasion. This loss is associated with the activation of the AhR pathway which reduced the expression of Twist1and IFITM1. IFITM1 overexpression can rescue impaired trophoblast migration.

DISCUSSION

Our study highlights that hydroquinone treatment induces the activation of the AhR pathway in trophoblast cells, which impairs trophoblast invasion and migration. We postulate that activation of the AhR pathway in trophoblast suppress Twist1 and a subsequent IFITM1. Thus, the AhR-Twist1-IFITM1 axis represent a critical pathway involved in the regulation of trophoblast migration and it is sensitive to benzene exposure. These findings provide crucial insights into the molecular mechanisms underlying pregnancy complications induced by air pollution.

Graphene oxide quantum dots-loaded sinomenine hydrochloride nanocomplexes for effective treatment of rheumatoid arthritis via inducing macrophage repolarization and arresting abnormal proliferation of fibroblast-like synoviocytes

The characteristic features of the rheumatoid arthritis (RA) microenvironment are synovial inflammation and hyperplasia. Therefore, there is a growing interest in developing a suitable therapeutic strategy for RA that targets the synovial macrophages and fibroblast-like synoviocytes (FLSs). In this study, we used graphene oxide quantum dots (GOQDs) for loading anti-arthritic sinomenine hydrochloride (SIN). By combining with hyaluronic acid (HA)-inserted hybrid membrane (RFM), we successfully constructed a new nanodrug system named HA@RFM@GP@SIN NPs for target therapy of inflammatory articular lesions. Mechanistic studies showed that this nanomedicine system was effective against RA by facilitating the transition of M1 to M2 macrophages and inhibiting the abnormal proliferation of FLSs in vitro. In vivo therapeutic potential investigation demonstrated its effects on macrophage polarization and synovial hyperplasia, ultimately preventing cartilage destruction and bone erosion in the preclinical models of adjuvant-induced arthritis and collagen-induced arthritis in rats. Metabolomics indicated that the anti-arthritic effects of HA@RFM@GP@SIN NPs were mainly associated with the regulation of steroid hormone biosynthesis, ovarian steroidogenesis, tryptophan metabolism, and tyrosine metabolism. More notably, transcriptomic analyses revealed that HA@RFM@GP@SIN NPs suppressed the cell cycle pathway while inducing the cell apoptosis pathway. Furthermore, protein validation revealed that HA@RFM@GP@SIN NPs disrupted the excessive growth of RAFLS by interfering with the PI3K/Akt/SGK/FoxO signaling cascade, resulting in a decline in cyclin B1 expression and the arrest of the G2 phase. Additionally, considering the favorable biocompatibility and biosafety, these multifunctional nanoparticles offer a promising therapeutic approach for patients with RA.

Hydroquinone, an Environmental Pollutant, Affects Cartilage Homeostasis through the Activation of the Aryl Hydrocarbon Receptor Pathway

Exposure to environmental pollutants has a proven detrimental impact on different aspects of human health. Increasing evidence has linked pollution to the degeneration of tissues in the joints, although through vastly uncharacterised mechanisms. We have previously shown that exposure to hydroquinone (HQ), a benzene metabolite that can be found in motor fuels and cigarette smoke, exacerbates synovial hypertrophy and oxidative stress in the synovium. To further understand the impact of the pollutant on joint health, here we investigated the effect of HQ on the articular cartilage. HQ exposure aggravated cartilage damage in rats in which inflammatory arthritis was induced by injection of Collagen type II. Cell viability, cell phenotypic changes and oxidative stress were quantified in primary bovine articular chondrocytes exposed to HQ in the presence or absence of IL-1β. HQ stimulation downregulated phenotypic markers genes SOX-9 and Col2a1, whereas it upregulated the expression of the catabolic enzymes MMP-3 and ADAMTS5 at the mRNA level. HQ also reduced proteoglycan content and promoted oxidative stress alone and in synergy with IL-1β. Finally, we showed that HQ-degenerative effects were mediated by the activation of the Aryl Hydrocarbon Receptor. Together, our findings describe the harmful effects of HQ on articular cartilage health, providing novel evidence surrounding the toxic mechanisms of environmental pollutants underlying the onset of articular diseases.

Toxic mechanisms of cigarette smoke and heat-not-burn tobacco vapor inhalation on rheumatoid arthritis

Tobacco combustion exposure worsens rheumatoid arthritis (RA). Non-combustible tobacco devices, as heat-not-burn tobacco (HNBT), are emerging as harm reduction to smokers by releasing nicotine and lower combustible tobacco products. Nevertheless, HNBT toxicity remains unclear. Hence, here we investigated the impacts of the tobacco combustible product (cigarette smoke; CS) or HNBT vapor exposures on antigen-induced arthritis (AIA) in C57BL/6 mice. Animals were exposed to airflow, HNBT vapor, or CS during 1 h/twice a day, under the Health Canada Intense (HCI) smoking regime, between days 14 to 20 after the first immunization. At day 21, 16 h after the last exposures, mice were i.a. challenged and the AIA effects were evaluated 24 h later. CS- or HNBT-exposed mice presented equivalent blood nicotine levels. CS exposure worsened articular symptoms, pulmonary inflammation, and expression of lung metallothioneins. Nevertheless, CS or HNBT exposures reduced lymphoid organs' cellularity, splenocyte proliferation and IL-2 secretion. Additional in vitro CS or HNBT exposures confirmed the harmful effects on splenocytes, which were partially mediated by the activation of nicotine/α7nAchR pathway. Associated, data demonstrate the toxic mechanisms of CS or HNBT inhalation at HCI regime on RA, and highlight that further investigations are fundamental to assure the toxicity of emerging tobacco products on the immune system during specific challenges.

Relationship between Antioxidant Activity and Ligand Basicity in the Dipicolinate Series of Oxovanadium(IV) and Dioxovanadium(V) Complexes

Oxidative stress plays an important role in the pathogenesis of many serious diseases, including cancer, atherosclerosis, coronary artery disease, Parkinson’s disease, Alzheimer’s disease, stroke and myocardial infarction. In the body’s natural biochemical processes, harmful free radicals are formed, which can be removed with the help of appropriate enzymes, a balanced diet or the supply of synthetic antioxidant substances such as flavonoids, vitamins or anthocyanins to the body. Due to the growing demand for antioxidant substances, new complex compounds of transition metal ions with potential antioxidant activity are constantly being sought. In this study, four oxovanadium(IV) and dioxovanadium(V) dipicolinate (dipic) complexes with 1,10-phenanthroline (phen), 2,2′-bipyridyl (bipy) and the protonated form of 2-phenylpyridine (2-phephyH): (1) [VO(dipic)(H₂O)₂]·2 H₂O, (2) [VO(dipic)(phen)]·3 H₂O, (3) [VO(dipic)(bipy)]·H₂O and (4) [VOO(dipic)](2-phepyH)·H₂O were synthesized including one new complex, so far unknown and not described in the literature, i.e., [VOO(dipic)](2-phepyH)·H₂O. The oxovanadium(IV) dipicolinate complexes with 1,10-phenanthroline and 2,2′-bipyridyl have been characterized by several physicochemical methods: NMR, MALDI-TOF-MS, IR, but new complex [VOO(dipic)](2-phepyH)·H₂O has been examined by XRD to confirm its structure. The antioxidant activities of four complexes have been examined by the nitrotetrazolium blue (NBT) method towards superoxide anion. All complexes exhibit high reactivity with superoxide anion and [VOO(dipic)](2-phepyH)·H₂O has higher antioxidant activity than L-ascorbic acid. Our studies confirmed that high basicity of the auxiliary ligand increases the reactivity of the complex with the superoxide radical.