Inhibition of KLF6 reduces the inflammation and apoptosis of type II alveolar epithelial cells in acute lung injury

Cirsium japonicum leaf extract attenuated lipopolysaccharide-induced acute respiratory distress syndrome in mice via suppression of the NLRP3 and HIF1α pathways

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a severe inflammatory disorder characterized by acute respiratory failure, alveolar barrier dysfunction, edema, and dysregulated alveolar macrophage-mediated pulmonary inflammation. Despite advancements in treatment strategies, the mortality rate in patients with ARDS remains high, ranging from 40-60 %. Current approaches are limited to supportive care, necessitating the exploration of effective therapeutic options such as suppressing broad inflammatory responses. Although Cirsium japonicum leaves possess anti-inflammatory properties, their specific effects on ARDS have not yet been investigated.

METHODS

The anti-inflammatory activity of Cirsium japonicum extract (CJE) was investigated in a lipopolysaccharide (LPS)-induced ARDS model.

RESULTS

CJE significantly attenuated LPS-induced lung injury, including reduced alveolar wall thickness, inflammatory cell infiltration, proteinaceous debris, and hyaline membranes. Moreover, CJE repressed infiltration of inflammatory cells and pro-inflammatory gene expression in bronchoalveolar lavage fluid. Concordantly, CJE mitigated alveolar macrophage activation, which consequently reduced neutrophil chemoattractic infiltration. Additionally, CJE suppressed NLRP3 and HIF1α expression in the lungs of the ARDS mouse. Similarly, LPS-induced NLRP3 and HIF1α pathway-associated inflammatory and glycolytic gene expressions significantly diminished by CJE in murine alveolar macrophage cell line, MH-S cells, and bone marrow-derived macrophages.

CONCLUSION

CJE suppressed multiple inflammatory responses through the regulation of NLRP3 and HIF1α signaling-related gene expression in macrophages of LPS-induced ARDS mice. These results suggest that CJE has therapeutic potential for treating patients with ARDS via macrophage regulation.

Upregulation of miR-22-3p Alleviates Hyperalgesia and Neuroinflammation Caused by Migraine

OBJECTIVE

Migraines profoundly impact patients' quality of life. This study seeks to investigate the relationship between dysregulated miR-22-3p and the neuroinflammation and central sensitization associated with migraine.

METHODS

Initially, the level of miR-22-3p in migraine patients were analyzed using RT-qPCR. Subsequently, a migraine model was established by administering nitroglycerin (NTG) to mice. To modulate the levels of miR-22-3p within this model, agomir was utilized. Following this intervention, mechanical and thermal pain sensitivity were evaluated by Von Frey filament and radiant heat. The levels of c-Fos, CGRP, TNF-α, IL-1β, and IL-6 in trigeminal nucleus caudalis (TNC) were detected by RT-qPCR and ELISA. Furthermore, dual luciferase reporting assays were conducted to ascertain whether miR-22-3p could target KLF6. Moreover, the influence of KLF6 on inflammatory cytokines and central sensitization were further studied.

RESULTS

miR-22-3p was significantly reduced in migraine patients and NTG mice. In animals, overexpression of miR-22-3p significantly alleviated hyperalgesia and neuroinflammation induced by NTG. Following the overexpression of miR-22-3p, we observed an increase in thermal withdrawal latency, paw mechanical threshold, and periorbital mechanical threshold. Conversely, levels of c-Fos, CGRP, TNF-α, IL-1β, and IL-6 exhibited a significant reduction. We found that miR-22-3p can inhibit KLF6 expression. Additionally, further findings indicated that the suppression of KLF6 resulted in decreased pain sensitivity along with diminished expression of c-Fos, CGRP, TNF-α, IL-1β, and IL-6.

CONCLUSION

In the context of migraine, miR-22-3p may play a pivotal role in mitigating neuroinflammation and alleviating central sensitization through the inhibition of KLF6.

Cinnamaldehyde Alleviates Alveolar Epithelial Cell Injury in ALI by Inhibiting the CaMKII Pathway

Alveolar epithelial cell injury plays a key role in acute lung injury (ALI) and is a vital determinant of its severity. Here, we aimed to assess the protective effects of cinnamaldehyde (CA) on lipopolysaccharide (LPS)-induced A549 cells and elucidate the underlying mechanisms. A549 cells were stimulated with 1 μg/mL LPS for 24 h to establish an alveolar epithelial cell injury model and subsequently treated with CA or Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor KN93. Flow cytometry, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and lactate dehydrogenase release assays were used to evaluate apoptosis, cell viability, and lactate dehydrogenase activity, respectively. Levels of inflammatory cytokines (interleukin-6, interleukin-1β, tumor necrosis tactor-α, and interferon-γ) and oxidative stress markers (reactive oxygen species, superoxide dismutase, catalase, and malondialdehyde) were determined using enzyme-linked immunosorbent assay and specific assay kits, respectively. Furthermore, levels of apoptosis-related proteins (cleaved caspase-3, Bcl-2-associated X, and Bcl-2) and CaMKII were assessed via western blotting. CA did not exhibit significant cytotoxicity in A549 cells. It dose-dependently improved the cell viability, suppressed apoptosis, decreased cleaved caspase-3 and Bcl-2-associated X levels, and increased Bcl-2 levels in LPS-treated A549 cells. It also inhibited inflammatory factor release and oxidative stress in LPS-induced A549 cells. Similar results were observed in the KN93- and CA-treated groups. Western blotting assay revealed that CA and KN93 inhibited CaMKII pathway activation, as indicated by the reduced p-CaMKII and p-phospholamban (PLN) levels and p-CaMKII/CaMKII and p-PLN/PLN ratios. Overall, CA alleviated alveolar epithelial cell injury by inhibiting the inflammatory response and oxidative stress and inducing cell apoptosis in LPS-induced A549 cells by regulating the CaMKII pathway, serving as a potential candidate for ALI prevention and treatment.

MicroRNA-22-3p in human umbilical cord mesenchymal stem cell-secreted exosomes inhibits granulosa cell apoptosis by targeting KLF6 and ATF4-ATF3-CHOP pathway in POF mice

BACKGROUND

Human umbilical cord mesenchymal stem cells (hUCMSCs)-derived exosomes carrying microRNAs (miRNAs) have promising therapeutic potential in various disorders, including premature ovarian failure (POF). Previous evidence has revealed the low plasma level of miR-22-3p in POF patients. Nevertheless, exosomal miR-22-3p specific functions underlying POF progression are unclarified.

METHODS

A cisplatin induced POF mouse model and in vitro murine ovarian granulosa cell (mOGC) model were established. Exosomes derived from miR-22-3p-overexpressed hUCMSCs (Exos-miR-22-3p) were isolated. CCK-8 assay and flow cytometry were utilized for measuring mOGC cell viability and apoptosis. RT-qPCR and western blotting were utilized for determining RNA and protein levels. The binding ability between exosomal miR-22-3p and Kruppel-like factor 6 (KLF6) was verified using luciferase reporter assay. Hematoxylin-eosin staining, ELISA, and TUNEL staining were performed for examining the alteration of ovarian function in POF mice.

RESULTS

Exos-miR-22-3p enhanced mOGC viability and attenuated mOGC apoptosis under cisplatin treatment. miR-22-3p targeted KLF6 in mOGCs. Overexpressing KLF6 reversed the above effects of Exos-miR-22-3p. Exos-miR-22-3p ameliorated cisplatin-triggered ovarian injury in POF mice. Exos-miR-22-3p repressed ATF4-ATF3-CHOP pathway in POF mice and cisplatin-treated mOGCs.

CONCLUSION

Exosomal miR-22-3p from hUCMSCs alleviates OGC apoptosis and improves ovarian function in POF mouse models by targeting KLF6 and ATF4-ATF3-CHOP pathway.