The crosstalk between M1 macrophage polarization and energy metabolism disorder contributes to polystyrene nanoplastics-triggered testicular inflammation

Micro-nanoplastics pollution and mammalian fertility: A systematic review and meta-analysis

MICRO: and nanoplastics (MNPs) are fragments derived from physical, chemical, or biological degradation of plastic items. MNPs are one of the main sources of both marine and terrestrial plastic pollution. This study systematically and meta-analytically assesses the reproductive toxicity in mammals of key plastic components found in MNPs, focusing on polystyrene (PS), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polyvinyl chloride (PVC). PubMed, Medline, and CAB Abstracts databases were used to identify the relevant scientific papers, and 79 articles were selected for the systematic review. Six articles included two different species, and 19 papers contained both in vivo and in vitro studies, resulting in a total of 102 experiments being considered and analysed in the meta-analysis. Interest in the reproductive toxicity of MNPs in mammals has increased, peaking in the last two years. Five species (rat, mouse, bovine, pig, and human) have been studied, with most experiments carried out in vivo in mice, focusing on male fertility. The most studied plastic polymer is PS, and both micro- and nanoparticles were tested at single or multiple concentrations. Toxic effects are documented across various species, particle size, and polymer type. A pronounced concentration-dependent toxicity has been observed, particularly at high concentrations/doses of MNPs. There is a gap in research on food-producing animals, which are both relevant models for human health and potential vectors for MNPs into the human food supply chain. Overall, these findings emphasizpe the importance of continued research to elucidate the pathways and mechanisms through which MNPs impact mammalian reproductive health, ultimately advancing our understanding of how these pervasive pollutants interact with biological systems across diverse species.

The Codonopsis pilosula water extract improves testicular inflammatory aging in D-galactose induced aging mice by modulating the CLEC7A/inflammasome pathway

AIM OF THE STUDY

Aging-induced testicular inflammation impairs male fertility. The purpose of this study was to investigate the effectiveness and mechanism of C. pilosula water extract (CPWE) in preventing testicular inflammation in D-galactose-induced aging mice.

MATERIALS AND METHODS

The "The Plant List" database (www.theplantlist.org) provided verified plant taxonomy. D-galactose was intraperitoneally injected to induce an aging mice model, with high, medium, and low dosages of CPWE used as pharmacological interventions. The concentrations of superoxide dismutase (SOD), malondialdehyde (MDA), testosterone and in mouse serum or testicle samples after CPWE treatment were quantified using biochemical method. Hematoxylin and eosin (HE) staining was employed to assess the morphological features of testicular tissues, whereas immunohistochemical (IHC) analysis and enzyme-linked immunosorbent assay (ELISA) were conducted to evaluate the presence and levels of inflammatory cytokines interleukin-6 (IL-6) and interleukin-1β (IL-1β) within testicular samples of mice. Differentially expressed genes were identified using transcriptome sequencing; the genes and pathways regulated by CPWE, as well as immune cell infiltration, were examined using bioinformatics analysis. The expression of target gene and pathway-related protein was confirmed using real-time quantitative PCR and Western blotting.

RESULTS

Treatment with CPWE alleviated the pathological alterations in the testicular tissues of aged mice, increased the concentrations of SOD and testosterone in the serum, and decreased the levels of MDA, IL-6 and IL-1β in the testes. The expression of C-C motif chemokine ligand 21a (Ccl21a) and C-C motif chemokine ligand 27b (Ccl27b) genes was downregulated after treatment with CPWE. The protein levels associated with the C-type lectin domain family 7, member A (CLEC7A)/inflammasome signaling pathway, including IL-1β, Caspase 8 (CASP8), and nuclear factor-kappa B (NF-κB), were found to be downregulated after treatment with CPWE. T cells, B cells, and macrophages showed a strong association with aging and the modulatory effects of CPWE.

CONCLUSIONS

The results indicate that CPWE regulates the CLEC7A/inflammasome pathway, thereby inhibiting inflammasomes activation and reducing the expressions of proinflammatory cytokines such as IL-6 and IL-1β, as well as chemokines such as Ccl21a and Ccl27b, providing substantial protection against age-related testicular inflammatory injury.

LT-α Facilitates the Aerobic Glycolysis and M1 Polarization of Macrophages by Activating the NF-κB Signaling Pathway in Intervertebral Disc Degeneration

Purpose

Injury and inflammatory activate and polarize macrophages in intervertebral disc degeneration (IVDD). Further research needs to be carried to explore the mechanisms that regulate macrophage polarization, providing new insights and targets for IVDD treatment. The aim of our study was to evaluate the influence of LT-α on aerobic glycolysis (AG) and polarization in macrophages.

Methods

M0 macrophages were achieved by stimulating THP-1 cells with PMA. M1 macrophages were obtained by IFN-γ and LPS stimulation in M0 macrophages. Energy metabolomics, AG and apoptosis related protein expression, migration and invasion measurement, proliferation was analyzed. Polarization of macrophages, AG associated genes expression, macrophage recruitment was evaluated. NF-κB signaling was ascertained by laser confocal and Western blotting.

Results

The propanoate metabolism pathway was enriched in LT-α overexpressing M0 macrophages, and various energy metabolites were detected. Glucose absorption, lactic acid production, and levels of AG proteins were strikingly increased in LT-α overexpression macrophages and remarkably repressed in LT-α knockdown macrophages, accompanied by activated and inactivated NF-κB signaling, respectively. Suppressed migration and invasion ability, restrained proliferation, activated AG, and enhanced apoptosis were observed in nucleus pulposus (NP) cells treated by LT-α overexpressed macrophages, accompanied by reduced macrophage recruitment, with opposite results when treated by LT-α knockdown macrophages. The enhanced M1 polarization and activated AG in LT-α overexpression macrophages were abolished by co-culturing with NF-κB inhibitor.

Conclusion

LT-α facilitates the AG and M1 polarization of macrophages via activating the NF-κB signaling pathway.

Biological Effects of Micro-/Nano-Plastics in Macrophages

The environmental impact of plastics is worsened by their inadequate end-of-life disposal, leading to the ubiquitous presence of micro- (MPs) and nanosized (NPs) plastic particles. MPs and NPs are thus widely present in water and air and inevitably enter the food chain, with inhalation and ingestion as the main exposure routes for humans. Many recent studies have demonstrated that MPs and NPs gain access to several body compartments, where they are taken up by cells, increase the production of reactive oxygen species, and lead to inflammatory changes. In most tissues, resident macrophages engage in the first approach to foreign materials, and this interaction largely affects the subsequent fate of the material and the possible pathological outcomes. On the other hand, macrophages are the main organizers and controllers of both inflammatory responses and tissue repair. Here, we aim to summarize the available information on the interaction of macrophages with MPs and NPs. Particular attention will be devoted to the consequences of this interaction on macrophage viability and functions, as well as to possible implications in pathology.

Polystyrene nanoplastics of different particle sizes regulate the polarization of pro-inflammatory macrophages

Microplastics (MPs) are defined as plastic particles smaller than 5 mm in size, and nanoplastics (NPs) are those MPs with a particle size of less than 1000 nm or 100 nm. The prevalence of MPs in the environment and human tissues has raised concerns about their potential negative effects on human health. Macrophages are the major defence against foreign substances in the intestine, and can be polarized into two types: the M1 phenotype and the M2 phenotype. However, the effect of NPs on the polarization of macrophages remains unclear. Herein, we selected polystyrene, one of the most plastics in the environment and controlled the particle sizes at 50 nm and 500 nm respectively to study the effects on the polarization of macrophages. We used mouse RAW264.7 cell line models in this macrophage-associated study. Experiments on cell absorption showed that macrophages could quickly ingest polystyrene nanoplastics of both diameters with time-dependent uptake. Compared to the untreated group and 10 μg/mL treatment group, macrophages exposed to 50 μg/mL groups (50 nm and 500 nm) had considerably higher levels of CD86, iNOS, and TNF-α, but decreased levels of aCD206, IL-10, and Arg-1. According to these findings, macrophage M1 and M2 polarization can both be induced and inhibited by 50 μg/mL 50 nm and 500 nm polystyrene nanoplastics. This work provided the first evidence of a possible MPs mode of action with appropriate concentration and size through the production of polarized M1, providing dietary and environmental recommendations for people, particularly those with autoimmune and autoinflammatory illnesses.

Adverse effects and potential mechanisms of polystyrene microplastics (PS-MPs) on the blood-testis barrier

Microplastics (MPs) are defined as plastic particles or fragments with a diameter of less than 5 mm. These particles have been identified as causing male reproductive toxicity, although the precise mechanism behind this association is yet to be fully understood. Recent research has found that exposure to polystyrene microplastics (PS-MPs) can disrupt spermatogenesis by impacting the integrity of the blood-testis barrier (BTB), a formidable barrier within mammalian blood tissues. The BTB safeguards germ cells from harmful substances and infiltration by immune cells. However, the disruption of the BTB leads to the entry of environmental pollutants and immune cells into the seminiferous tubules, resulting in adverse reproductive effects. Additionally, PS-MPs induce reproductive damage by generating oxidative stress, inflammation, autophagy, and alterations in the composition of intestinal flora. Despite these findings, the precise mechanism by which PS-MPs disrupt the BTB remains inconclusive, necessitating further investigation into the underlying processes. This review aims to enhance our understanding of the pernicious effects of PS-MP exposure on the BTB and explore potential mechanisms to offer novel perspectives on BTB damage caused by PS-MPs.

Melatonin improves influenza virus infection-induced acute exacerbation of COPD by suppressing macrophage M1 polarization and apoptosis

BACKGROUND

Influenza A viruses (IAV) are extremely common respiratory viruses for the acute exacerbation of chronic obstructive pulmonary disease (AECOPD), in which IAV infection may further evoke abnormal macrophage polarization, amplify cytokine storms. Melatonin exerts potential effects of anti-inflammation and anti-IAV infection, while its effects on IAV infection-induced AECOPD are poorly understood.

METHODS

COPD mice models were established through cigarette smoke exposure for consecutive 24 weeks, evaluated by the detection of lung function. AECOPD mice models were established through the intratracheal atomization of influenza A/H3N2 stocks in COPD mice, and were injected intraperitoneally with melatonin (Mel). Then, The polarization of alveolar macrophages (AMs) was assayed by flow cytometry of bronchoalveolar lavage (BAL) cells. In vitro, the effects of melatonin on macrophage polarization were analyzed in IAV-infected Cigarette smoking extract (CSE)-stimulated Raw264.7 macrophages. Moreover, the roles of the melatonin receptors (MTs) in regulating macrophage polarization and apoptosis were determined using MTs antagonist luzindole.

RESULTS

The present results demonstrated that IAV/H3N2 infection deteriorated lung function (reduced FEV20,50/FVC), exacerbated lung damages in COPD mice with higher dual polarization of AMs. Melatonin therapy improved airflow limitation and lung damages of AECOPD mice by decreasing IAV nucleoprotein (IAV-NP) protein levels and the M1 polarization of pulmonary macrophages. Furthermore, in CSE-stimulated Raw264.7 cells, IAV infection further promoted the dual polarization of macrophages accompanied with decreased MT1 expression. Melatonin decreased STAT1 phosphorylation, the levels of M1 markers and IAV-NP via MTs reflected by the addition of luzindole. Recombinant IL-1β attenuated the inhibitory effects of melatonin on IAV infection and STAT1-driven M1 polarization, while its converting enzyme inhibitor VX765 potentiated the inhibitory effects of melatonin on them. Moreover, melatonin inhibited IAV infection-induced apoptosis by suppressing IL-1β/STAT1 signaling via MTs.

CONCLUSIONS

These findings suggested that melatonin inhibited IAV infection, improved lung function and lung damages of AECOPD via suppressing IL-1β/STAT1-driven macrophage M1 polarization and apoptosis in a MTs-dependent manner. Melatonin may be considered as a potential therapeutic agent for influenza virus infection-induced AECOPD.

Polystyrene Nanoplastics Activate Autophagy and Suppress Trophoblast Cell Migration/Invasion and Migrasome Formation to Induce Miscarriage

Nanoplastics (NPs), as emerging pollutants, have attracted global attention. Nevertheless, the adverse effects of NPs on female reproductive health, especially unexplained miscarriage, are poorly understood. Defects of trophoblast cell migration and invasion are associated with miscarriage. Migrasomes were identified as cellular organelles with largely unidentified functions. Whether NPs might affect migration, invasion, and migrasome formation and induce miscarriage has been completely unexplored. In this study, we selected polystyrene nanoplastics (PS-NPs, 50 nm) as a model of plastic particles and treated human trophoblast cells and pregnant mice with PS-NPs at doses near the actual environmental exposure doses of plastic particles in humans. We found that exposure to PS-NPs induced a pregnant mouse miscarriage. PS-NPs suppressed ROCK1-mediated migration/invasion and migrasome formation. SOX2 was identified as the transcription factor of ROCK1. PS-NPs activated autophagy and promoted the autophagy degradation of SOX2, thus suppressing SOX2-mediated ROCK1 transcription. Supplementing with murine SOX2 or ROCK1 could efficiently rescue migration/invasion and migrasome formation and alleviate miscarriage. Analysis of the protein levels of SOX2, ROCK1, TSPAN4, NDST1, P62, and LC-3BII/I in PS-NP-exposed trophoblast cells, villous tissues of unexplained miscarriage patients, and placental tissues of PS-NP-exposed mice gave consistent results. Collectively, this study revealed the reproductive toxicity of nanoplastics and their potential regulatory mechanism, indicating that NP exposure is a risk factor for female reproductive health.