Effect of Urban Particulate Matter on Vocal Fold Fibrosis through the MAPK/NF-κB Signaling Pathway

Promotion of myofibroblast differentiation through repeated treatment of fibroblasts to low concentrations of PM2.5

Exposure to particulate matter ≤ 2.5 µm (PM2.5) is a risk factor for many lung diseases. Although the toxicologic effects of PM2.5 on airway epithelium are well-described, the effects of PM2.5 on fibroblasts in the lung are less studied. Here, we sought to examine the effects of PM2.5 on the differentiation of fibroblasts into myofibroblasts. Although a single treatment of fibroblasts did not result in a change in collagen or the myofibroblast marker α-SMA, exposing fibroblasts to sequential treatments with PM2.5 at low concentrations caused a robust increase in these proteins. Treatment of fibroblasts with IMD0354, an inhibitor to nuclear factor κB, but not with an antagonist to aryl hydrocarbon receptor, abolished the ability of PM2.5 to induce myofibroblast differentiation. These data demonstrate that potential impact of PM2.5 to fibroblast activation and fibrosis and support the importance of utilizing low concentrations and varying exposure protocols to toxicologic studies.

Exosomes from adipose-derived mesenchymal stem cells improve liver fibrosis by regulating the miR-20a-5p/TGFBR2 axis to affect the p38 MAPK/NF-κB pathway

OBJECTIVE

Human adipose-derived mesenchymal stem cell exosomes (ADSC-Exos) are active constituents for treating liver fibrosis. This paper attempted to preliminarily explain the functional mechanism of ADSC-Exos in liver fibrosis through the p38 MAPK/NF-κB pathway.

METHODS

The cell models of hepatic fibrosis were established by inducing LX-2 cells with TGF-β1. Mouse models of liver fibrosis were established by treating mice with CCl4. The in vivo and in vitro models of liver fibrosis were treated with ADSC-Exos. ADSCs were identified by flow cytometry/Alizarin red/oil red O/alcian blue staining. ADSC-Exos were identified by transmission electron microscopy, nanoparticle tracking analysis, and Western blot. LX-2 cell proliferation/viability were evaluated by MTT/BrdU assays. Exosomes were tracked in vivo and body weight changes in mice were monitored. Hepatic pathological changes were observed by HE/Masson staining. α-SMA/collagen I levels in liver tissues were assessed by immunohistochemistry. HA/PIIINP concentrations were measured using the magnetic particle chemiluminescence method. Liver function was assessed using an automatic analyzer. miR-20a-5p level was measured by RT-qPCR. The mRNA levels of fibrosis markers were determined by RT-qPCR, and their protein levels and levels of MAPK/NF-κB pathway-related proteins, as well as TGFBR2 protein level were measured by Western blot. The P65 nuclear expression in mouse liver tissues was quantified by immunofluorescence.

RESULTS

ADSC-Exos suppressed TGF-β1-induced LX-2 cell proliferation and fibrosis and reduced mRNA and protein levels of fibrosis markers in vitro. ADSC-Exos ameliorated liver fibrosis by inhibiting the p38 MAPK/NF-κB pathway activation. ADSC-Exos inhibited activation of the p38 MAPK/NF-κB pathway via regulating the miR-20a-5p/TGFBR2 axis. The in vivo experiment asserted that ADSC-Exos were mainly distributed in the liver, and ADSC-Exos relieved liver fibrosis in mice, which was evidenced by alleviating decreased body weight, reducing collagen and enhancing liver function, and repressed the activation of the p38 MAPK/NF-κB pathway via the miR-20a-5p/TGFBR2 axis.

CONCLUSION

ADSC-Exos attenuated liver fibrosis by suppressing the activation of the p38 MAPK/NF-κB pathway via the miR-20a-5p/TGFBR2 axis.

In Vitro Evaluation of Biomaterials for Vocal Fold Injection: A Systematic Review

Vocal fold injection is a preferred treatment in glottic insufficiency because it is relatively quick and cost-saving. However, researchers have yet to discover the ideal biomaterial with properties suitable for human vocal fold application. The current systematic review employing PRISMA guidelines summarizes and discusses the available evidence related to outcome measures used to characterize novel biomaterials in the development phase. The literature search of related articles published within January 2010 to March 2021 was conducted using Scopus, Web of Science (WoS), Google Scholar and PubMed databases. The search identified 6240 potentially relevant records, which were screened and appraised to include 15 relevant articles based on the inclusion and exclusion criteria. The current study highlights that the characterization methods were inconsistent throughout the different studies. While rheologic outcome measures (viscosity, elasticity and shear) were most widely utilized, there appear to be no target or reference values. Outcome measures such as cellular response and biodegradation should be prioritized as they could mitigate the clinical drawbacks of currently available biomaterials. The review suggests future studies to prioritize characterization of the viscoelasticity (to improve voice outcomes), inflammatory response (to reduce side effects) and biodegradation (to improve longevity) profiles of newly developed biomaterials.