Worsening of imiquimod-induced psoriasiform inflammation in mice by environmental pollutant, di-(2-ethylhexyl) phthalate through dysregulation in IL-17A and Nrf2/iNOS signaling in peripheral myeloid and CD4 + T cells

Mechanisms of pulmonary fibrosis and lung cancer induced by chronic PM2.5 exposure: Focus on the airway epithelial barrier and epithelial-mesenchymal transition

This study aims to provide new insights into PM2.5-induced lung diseases through a focus on the pulmonary epithelial barrier and epithelial-mesenchymal transition (EMT). Firstly, we analyzed the mechanisms by which PM2.5 damages the airway epithelial barrier, including inflammatory responses, immune imbalance, oxidative stress, apoptosis, and autophagy. Subsequently, we investigated the mechanisms by which PM2.5 induces EMT, which involve the synergistic effect of oxidative stress and inflammation, the activation of key signaling pathways, and the regulatory role of non-coding RNAs. Furthermore, we explored the interaction between the airway epithelial barrier and EMT, especially the induction of EMT by epithelial barrier damage and the impact of EMT on epithelial barrier repair. Regarding lung injury diseases, we focused on the roles of the epithelial barrier and EMT in the development of pulmonary fibrosis and lung cancer, providing evidence from in vitro and in vivo studies. Emphasizing the translational prospects from basic research to clinical applications, and we proposed new ideas for treating PM2.5-related lung diseases from four aspects-anti-inflammatory and antioxidant drugs, signaling pathway inhibitors, non-coding RNA-targeted therapies, and gene editing and cell therapies-by focusing on the two key links of the airway epithelial barrier and EMT.

DEHP (di(2-ethylhexyl)phthalate) stimulates skin pigmentation by perturbing cytoskeletal homeostasis

Phthalates are extensively employed plasticizers crucial for conferring flexibility and plasticity to polyvinyl chloride. Phthalates, including DEHP (di(2-ethylhexyl)phthalate), present in diverse products, have been identified in fine dust and are capable of infiltrating the body, potentially posing health hazards. Importantly, melanocytes, existing at the basal layer of the epidermis, are susceptible to toxic substances. In our study, we employed the 3D human pigmented epidermis model, MelanoDerm™, along with the B16F10 murine melanoma cell line, to examine the influence of DEHP exposure on melanocytes. The exposure to low concentrations of DEHP (~ 5 μM), resulted in the extension of melanocyte dendrites, indicating the stimulation of melanocytes. Analysis of gene expression and protein profiles unveiled the up-regulation of MITF, Arpc2, and TRP1 genes subsequent to DEHP exposure, indicating alterations in cytoskeletal and melanosome-related genetic and protein components in melanocytes. Notably, increased pigmentation was observed in MelanoDerm™ following DEHP exposure. DEHP-stimulated reactive oxygen species generation appeared to be involved in these events since the antioxidant, ascorbic acid attenuated ROS generation and MITF upregulation. Collectively, our study demonstrated that DEHP exposure can induce cytoskeletal disturbance and skin pigmentation through oxidative stress.

Pentraxin 3 exacerbates psoriasiform dermatitis through regulation of macrophage polarization

OBJECTIVE

To elucidate the mechanism of Pentraxin 3 (PTX3) in the pathogenesis of psoriasiform dermatitis using Ptx3-knockout (Ptx3-KO) background mice.

METHODS

An Imiquimod (IMQ)-induced murine psoriatic model was created using Ptx3-KO (Ptx3-/-) and wild-type (Ptx3+/+) mice. Skin lesion severity and expression of inflammatory mediators (IL-6 and TNFα) were assessed using PASI score and ELISA, respectively. Cutaneous tissues from the two mice groups were subjected to histological analyses, including HE staining, Masson staining, and Immunohistochemistry (IHC). The PTX3, iNOS, COX2, and Arg1 expressions were quantified and compared between the two groups. We used RNA-seq to clarify the underlying mechanisms of the disease. Flow cytometry was used to analyze systemic Th17 cell differentiation and macrophage polarization.

RESULT

The psoriatic region exhibited a higher PTX3 expression than the normal cutaneous area. Moreover, PTX3 was upregulated in HaCaT cells post-TNFα stimulation. Upon IMQ stimulation, Ptx3-/- mice displayed a lower degree of the psoriasiform dermatitis phenotype compared to Ptx3+/+ mice. Consistent with the RNA-seq results, further experiments confirmed that compared to the wild-type group, the PTX3-KO group exhibited a generally lower IL-6, TNFα, iNOS, and COX2 expression and a contrasting trend in macrophage polarization. However, no significant difference in Th17 cell activation was observed between the two groups.

CONCLUSIONS

This study revealed that PTX3 was upregulated in psoriatic skin tissues and TNFα-stimulated HaCaT cells. We also discovered that PTX3 deficiency in mice ameliorated the psoriasiform dermatitis phenotype upon IMQ stimulation. Mechanistically, PTX3 exacerbates psoriasiform dermatitis by regulating macrophage polarization rather than Th17 cell differentiation.