No abstract

The mesenchymal stem cell (MSC) is a potential strategy in the pretreatment of traumatic acute lung injury (ALI), a disease that causes inflammation and oxidative stress. This study aimed to investigate whether MSC-exosomal microRNA-124-3p (miR-124-3p) affects traumatic ALI. Initially, a traumatic ALI rat model was established using the weight-drop method. Then, exosomes were obtained from MSCs of Sprague-Dawley rats, which were injected into the traumatic ALI rats. We found that miR-124-3p was abundantly-expressed in MSCs-derived exosomes and could directly target purinergic receptor P2X ligand-gated ion channel 7 (P2X7), which was overexpressed in traumatic ALI rats. After that, a loss- and gain-of-function study was performed in MSCs and traumatic ALI rats to investigate the role of miR-124-3p and P2X7 in traumatic ALI. MSC-derived exosomal miR-124-3p or silenced P2X7 was observed to increase the survival rate of traumatic ALI rats and enhance the glutathione/superoxide dismutase activity in their lung tissues. However, the wet/dry weight of lung tissues, activity of methylenedioxyamphetamine and H2O2, and levels of inflammatory factors (TNF-a, IL-6, and IL-8) were reduced. Similarly, the numbers of total cells, macrophages, neutrophils, and lymphocytes in bronchoalveolar lavage fluid were also reduced when treated with exosomal miR-124-3p or silenced P2X7. In conclusion, the results provide evidence that miR-124-3p transferred by MSC-derived exosomes inhibited P2X7 expression, thus improving oxidative stress injury and suppressing inflammatory response in traumatic ALI, highlighting a potential pretreatment for traumatic ALI.

Rationale:Negative pressure pulmonary edema (NPPE) is a dangerous clinical complication and potentially life-threatening emergency without prompt diagnosis and intervention during recovery period after anesthetic extubation.Patient concerns:A 25-year-old woman has undergone endoscopic thyroidectomy. After extubation, the patient developed acute respiratory distress with high airway resistance accompanied with wheezing, oxyhemoglobin saturation (SpO2) decreased to 70%. With positive pressure mask ventilation, her condition was stable, SpO2 99%. However, the patient developed pink frothy sputum with diffuse bilateral rales 30 min later after transported to surgical intensive care unit (SICU).Diagnoses:Negative pressure pulmonary edema.Interventions:The patient was undergone assisted ventilation with continuous positive airway pressure (CPAP) and furosemide 20 mg was given intravenously.Outcomes:Postoperative day (POD) 2 her condition became stable, computed tomography (CT) scan indicated the pulmonary edema disappeared. The patient was discharged 6 days later. No abnormalities were observed during following 4 weeks.Lessons:Although usually the onset of NPPE is rapid, with individual differences NPPE is still challenging. Increased vigilance in monitoring, diagnosis, and treatment are essential to prevent aggravation and further complication.

Background/Aims: Chronic respiratory conditions continue to plague millions of people worldwide. We aimed to elucidate the detailed mechanisms of microRNA-485 (miR-485) in airway smooth muscle cell (ASMC) proliferation and apoptosis in chronic asthmatic mice. Methods: A mouse model of chronic asthma was established. Ovalbumin was used to induce chronic asthma in the mice. The levels of transforming growth factor β (TGF-β), interleukin (IL)-4, IL-5, IL-13 and IL-17 in bronchoalveolar lavage fluid in mice were measured by enzyme-linked immunoassays (ELISAs). ASMCs were transfected with miR-485 mimic, miR-485 inhibitor and siRNA-Smurf2. The reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analyses were applied to detect the mRNA and protein levels of Smurf2, α-SMA, TGF-β1 and decapentaplegic homolog (Smads). The MTT assay was utilized for cell proliferation, while flow cytometry was conducted to assess cell cycle distribution and apoptosis. Results: Lower expression of miR-485 and higher expression levels of TGF-β1, IL-4, IL-5, IL-13 and IL-17 were detected in mice with chronic asthma. Smurf2 was identified as the target gene of miR-485. Upregulation of miR-485 mimic and downregulation of Smurf2 decreased expression levels of Smurf2, α-SMA, TGF-β1 and Smad3, inhibited cell proliferation and increased apoptosis, while contrary results were observed in ASMCs transfected with miR-485 inhibitor. Conclusion: Overexpressed miR-485 inhibits cell proliferation and promotes apoptosis of ASMCs through the Smurf2-mediated TGF-β/Smads signaling pathway in mice with chronic asthma.

Background Pain is one of the most common and distressing symptoms suffered by patients with progression of cancer; however, the mechanisms responsible for hyperalgesia are not well understood. Since the midbrain periaqueductal gray is an important component of the descending inhibitory pathway controlling on central pain transmission, in this study, we examined the role for pro-inflammatory cytokines of the periaqueductal gray in regulating mechanical and thermal hyperalgesia evoked by bone cancer via phosphatidylinositide 3-kinase (PI3K)–mammalian target of rapamycin (mTOR) signals. Methods Breast sarcocarcinoma Walker 256 cells were implanted into the tibia bone cavity of rats to induce mechanical and thermal hyperalgesia. Western blot analysis and ELISA were used to examine PI3K/protein kinase B (Akt)/mTOR and pro-inflammatory cytokine receptors and the levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α). Results Protein expression levels of p-PI3K/p-Akt/p-mTOR were amplified in the periaqueductal gray of bone cancer rats, and blocking PI3K–mTOR pathways in the periaqueductal gray attenuated hyperalgesia responses. In addition, IL-1β, IL-6, and TNF-α were elevated in the periaqueductal gray of bone cancer rats, and expression of their respective receptors (namely, IL-1R, IL-6R, and tumor necrosis factor receptor (TNFR) subtype TNFR1) was upregulated. Inhibition of IL-1R, IL-6R, and TNFR1 alleviated mechanical and thermal hyperalgesia in bone cancer rats, accompanied with downregulated PI3K–mTOR. Conclusions Our data suggest that upregulation of pro-inflammatory cytokine signal in the periaqueductal gray of cancer rats amplifies PI3K–mTOR signal in this brain region and alters the descending pathways in regulating pain transmission, and this thereby contributes to the development of bone cancer-induced pain.

Background/Aims: Bortezomib (BTZ) is largely used as a chemotherapeutic agent for the treatment of cancer. However, one of the significant limiting complications of BTZ is painful peripheral neuropathy during BTZ therapy. Drugs preventing and/or treating the painful symptoms induced by BTZ are lacking since the underlying mechanisms leading to neuropathic pain remain largely unclear. The purposes of this study were to examine 1) the effects of blocking mammalian target of rapamycin (mTOR) on mechanical pain and cold hypersensitivity evoked by BTZ and 2) the underlying mechanisms responsible for the role of mTOR in regulating BTZ-induced neuropathic pain. Methods: Behavioral test was performed to determine mechanical pain and cold sensitivity in a rat model. Western blot analysis and ELISA were used to examine expression of mTOR and phosphatidylinositide 3-kinase (p-PI3K) signals, and the levels of substance P and calcitonin gene-related peptide (CGRP). Results: Systemic injection of BTZ significantly increased mechanical pain and cold sensitivity as compared with control animals (P<0.05 vs. control rats). The expression of p-mTOR, mTORmediated phosphorylation of p70 ribosomal S6 protein kinase 1 (p-S6K1), 4E-binding protein 4 (p-4E-BP1) as well as p-PI3K was amplified in the dorsal horn of spinal cord of BTZ rats as compared with control rats. Blocking mTOR by intrathecal infusion of rapamycin attenuated mechanical pain and cold hypersensitivity. Blocking PI3K signal also attenuated activities of mTOR, which was accompanied with decreasing neuropathic pain. Inhibition of either mTOR or PI3K blunted enhancement of the spinal substance P and CGRP in BTZ rats. Conclusions: The data for the first time revealed specific signaling pathways leading to BTZ-induced peripheral neuropathic pain, including the activation of mTOR and PI3K. Inhibition of these signal pathways alleviates pain. Targeting one or more of these signaling molecules may present new opportunities for treatment and management of peripheral painful neuropathy observed during chemotherapeutic application of BTZ.

BackgroundOxaliplatin is a third-generation chemotherapeutic agent that is commonly used to treat metastatic digestive tumors; however, one of the main limiting complications of oxaliplatin is painful peripheral neuropathy. The purpose of this study was to examine the underlying mechanisms by which mammalian target of rapamycin (mTOR) and its signal are responsible for oxaliplatin-evoked neuropathic pain.MethodsNeuropathic pain was induced by intraperitoneal injection of oxaliplatin in rats. ELISA and Western blot analysis were used to examine the levels of pro-inflammatory cytokines (including interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α) and the expression of mTOR signal pathway.ResultsOxaliplatin increased mechanical and cold sensitivity as compared with control animals (P < 0.05 vs. control rats). Oxaliplatin also amplified the expression of p-mTOR and mTOR-mediated phosphorylation of p70 ribosomal S6 protein kinase 1 and 4E-binding protein 1 in the lumbar dorsal root ganglion. Blocking mTOR using rapamycin attenuated peripheral painful neuropathy observed in oxaliplatin rats (P < 0.05 vs. vehicle control). This inhibitory effect was accompanied with decreases of IL-1β, IL-6, and TNF-α. In addition, inhibition of phosphatidylinositide 3-kinase (p-PI3K) attenuated the expression of p-mTOR and the levels of pro-inflammatory cytokines in oxaliplatin rats, and this further attenuated mechanical and cold hypersensitivity.ConclusionsThe data revealed specific signaling pathways leading to oxaliplatin-induced peripheral neuropathic pain, including the activation of PI3K-mTOR and pro-inflammatory cytokine signal. Inhibition of these pathways alleviates neuropathic pain. Targeting one or more of these molecular mediators may present new opportunities for treatment and management of neuropathic pain observed during chemotherapeutic application of oxaliplatin.

Background/Aims: Asthma is a heterogeneous disease characterized by chronic airway inflammation resulting from airway hyper-responsiveness to diverse stimuli. In this study, we investigated whether microRNA-142 (miR-142) expression affects proliferation and apoptosis in airway smooth muscle cells (ASMCs) during airway remodeling in asthmatic rats. Methods: Thirty six Wistar rats were randomly classified into a control group and an model group. miR-142 mimics and inhibitors were constructed, and ASMCs were transfected using liposomes according to the following groups: blank, negative control (NC), miR-142 mimics, miR-142 inhibitors, si-TGF-β and miR-142 inhibitors + si-TGF-β. We verified that miR-142 targets TGF-β using a dual-luciferase reporter assay. The expression levels of miR-142, TGF-β, EGFR and apoptosis signaling pathway-related genes were determined using RT-qPCR and western blotting. Changes in cell proliferation, cell cycle progression and apoptosis were analyzed using MTT assays and flow cytometry. Results: Rats with asthma had higher expression levels of EGFR and Akt and lower miR-142 levels. miR-142 was negatively correlated with TGF-β expression. In ASMCs, the expression of TGF-β, EGFR, Akt, phosphorylated-Akt (p-Akt), Bcl-2 and Bcl-xl and the rate of early apoptosis were decreased while expression of Bax and p21 and the proliferation rate were elevated with the upregulation of miR-142. The opposite results were observed with the downregulation of miR-142. Finally, the proliferative rate was decreased while the apoptosis rate was increased and expression levels of EGFR, Akt, p-Akt, Bcl-2 and Bcl-xl were reduced while Bax and p21 were elevated in the ASMCs transfected with miR-142 inhibitors and si-TGF-β. Conclusion: The results of our study suggest that miR-142 inhibits proliferation and promotes apoptosis in ASMCs during airway remodeling in asthmatic rats by inhibiting TGF-β expression via a mechanism involving the EGFR signaling pathway.