Mitochondria-lysosome-related organelles mediate mitochondrial clearance during cellular dedifferentiation.

Dysfunctional mitochondria are removed via multiple pathways, such as mitophagy, a selective autophagy process. Here, we identify an intracellular hybrid mitochondria-lysosome organelle (termed the mitochondria-lysosome-related organelle [MLRO]), which regulates mitochondrial homeostasis independent of canonical mitophagy during hepatocyte dedifferentiation. The MLRO is an electron-dense organelle that has either a single or double membrane with both mitochondria and lysosome markers. Mechanistically, the MLRO is likely formed from the fusion of mitochondria-derived vesicles (MDVs) with lysosomes through a PARKIN-, ATG5-, and DRP1-independent process, which is negatively regulated by transcription factor EB (TFEB) and associated with mitochondrial protein degradation and hepatocyte dedifferentiation. The MLRO, which is galectin-3 positive, is reminiscent of damaged lysosome and could be cleared by overexpression of TFEB, resulting in attenuation of hepatocyte dedifferentiation. Together, results from this study suggest that the MLRO may act as an alternative mechanism for mitochondrial quality control independent of canonical autophagy/mitophagy involved in cell dedifferentiation.

Activation of α7 nicotinic acetylcholine receptor retards the development of endometriosis.

BACKGROUND: Women with endometriosis have been shown to have a reduced vagal tone as compared with controls and vagotomy promoted while vagus nerve stimulation (VNS) decelerated the progression of endometriosis in mice. Extensive research also has shown that the activation of the cholinergic anti-inflammatory pathway by VNS activates α7 nicotinic acetylcholine receptor (α7nAChR), potently reducing inflammation. Yet whether α7nAChR plays any role in endometriosis is unknown. We evaluated its expression in normal endometrium, ovarian and deep endometriotic lesions, and evaluated its role in the development of endometriosis. METHODS: Immunohistochemistry analyses of α7nAChR in endometriotic lesions as well as control endometrium, and quantification of tissue fibrosis by Masson trichrome staining were performed. Mouse experiments were conducted to evaluate the impact of α7nAChR activation or suppression on lesional progression and possible therapeutic effect. Finally, in vitro experiments were conducted to evaluate the effect of activation of α7nAChR on epithelial-mesenchymal transition (EMT), fibroblast-to-myofibroblast transdifferentiation (FMT), smooth muscle metaplasia (SMM) and fibrogenesis in an endometriotic epithelial cell line and primary endometriotic stromal cells derived from ovarian endometrioma tissue samples. RESULTS: Immunostaining of α7nAChR was significantly reduced in human endometriotic epithelial cells as compared with their counterpart in normal endometrium. Lesional α7nAChR staining levels correlated negatively with lesional fibrosis and the severity of dysmenorrhea. The α7nAChR agonist significantly impeded the development of endometriotic lesions in mouse models possibly through hindrance of EMT and FMT. It also demonstrated therapeutic effects in mice with induced deep endometriosis. Treatment of endometriotic epithelial and stromal cells with an α7nAChR agonist significantly abrogated platelet-induced EMT, FMT and SMM, and suppressed cellular contractility and collagen production. CONCLUSIONS: α7nAChR is suppressed in endometriotic lesions, and its activation by pharmacological means can impede EMT, FMT, SMM, and fibrogenesis of endometriotic lesions. As such, α7nAChR can be rightfully viewed as a potential target for therapeutic invention. TRIAL REGISTRATION: Not applicable.

Kaempferol alleviates human endothelial cell injury through circNOL12/miR-6873-3p/FRS2 axis.

BACKGROUND: Atherosclerosis, inflammatory disease, is a major reason for cardiovascular diseases and stroke. Kaempferol (Kae) has been well-documented to have pharmacological activities in the previous studies. However, the detailed mechanisms by which Kae regulates inflammation, oxidative stress, and apoptosis in Human Umbilical Vein Endothelial Cells (HUVECs) remain unknown. METHODS AND RESULTS: The real-time quantitative polymerase chain reaction (RT-qPCR) was used to measure expression levels of circNOL12, nucleolar protein 12 (NOL12), miR-6873-3p, and Fibroblast growth factor receptor substrate 2 (FRS2) in HUVECs treated with either oxidized low-density lipoprotein (ox-LDL) alone or in combination with Kae. The cells viability was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide (MTT) assay. The inflammation and oxidative stress were assessed by checking inflammatory factors, Reactive Oxygen Species (ROS), Superoxide Dismutase (SOD), and Malondialdehyde (MDA) levels in ox-LDL-induced HUVECs. The apoptotic cells were quantified by flow cytometry assay. The western blot assay was used for measuring protein expression. The interaction relationship between miR-6873-3p and circNOL12 or FRS2 was analyzed by dual-luciferase reporter and RNA pull-down assays. Treatment with Kae could inhibit ox-LDL-induced the upregulation of circNOL12 in HUVECs. Importantly, Kae weakened ox-LDL-induced inflammation, oxidative stress, and apoptosis in HUVECs, which was abolished by overexpression of circNOL12. What's more, miR-6873-3p was a target of circNOL12 in HUVECs, and the upregulation of miR-6873-3p overturned circNOL12 overexpression-induced effects on HUVECs treated with ox-LDL and Kae. FRS2 was negatively regulated by miR-6873-3p in HUVECs. CONCLUSION: Kae alleviated ox-LDL-induced inflammation, oxidative stress, and apoptosis in HUVECs by regulating circNOL12/miR-6873-3p/FRS2 axis.

Reduced vagal tone in women with endometriosis and auricular vagus nerve stimulation as a potential therapeutic approach.

Sensory and sympathetic nerves have been shown to promote the progression of endometriosis through the release of neuromediators and the lesional activation of respective receptors. The role of vagus nerves (VN) in lesional progression, however, is completely unclear, despite the signs suggestive of increased sympathetic tone in women with endometriosis. This study was undertaken to investigate whether VN plays any role in the progression of endometriosis. We recruited 45 patients with endometriosis and 42 healthy women, who were given electrocardiogram test and their heart rate variability was evaluated. In addition, three prospective, and randomized mouse experiments were conducted that evaluated, respectively, the effect of vagotomy, the effect of VN stimulation (VNS), and the therapeutic potential of VNS after the endometriosis was well established. All lesions were excised, weighed, and processed for immunohistochemistry and histochemistry analysis of select markers for lesional progression and fibrosis. We found that endometriosis patients exhibited reduced vagal activity as compared with controls, indicative of disrupted autonomic balance. Vagotomy increased while VNS decreased the lesion weight as compared with control mice, concomitant with more progressive and retarded lesion development and fibrogenesis, respectively. In addition, VNS demonstrated promising therapeutic effect, as evidenced by significantly reduced lesion weight, more attenuated lesional progression concomitant with improved hyperalgesia. Taken together, our data indicate that VN activity may play a dampening role in the progression of endometriosis. Consequently, boosting the VN activity may have therapeutic potentials for patients with endometriosis.

CircATP2B4 promotes hypoxia-induced proliferation and migration of pulmonary arterial smooth muscle cells via the miR-223/ATR axis.

BACKGROUND: Circular RNAs (circRNAs) function as important modulators in the progression of pulmonary arterial hypertension (PAH). Here, we aimed to discover the role and working mechanism of circATP2B4 in hypoxia-induced proliferation and migration of PASMCs. METHODS: The proliferation, migration and apoptosis of pulmonary arterial smooth muscle cells (PASMCs) were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound healing assay and flow cytometry. The expression of circATP2B4, ATPase plasma membrane Ca2+ transporting 4 (ATP2B4), microRNA-223 (miR-223) and ATR serine/threonine kinase (ATR) was quantified by quantitative real time polymerase chain reaction (qRT-PCR). Circular RNA Interactome and microT-CDS were used to search the targets of circATP2B4 and miR-223, respectively. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to validate the above predictions. Western blot assay was performed to detect the protein expression of ATR. RESULTS: Hypoxia treatment promoted the proliferation and migration and impeded the apoptosis of PASMCs. A significant increase of circATP2B4 expression was observed in the serum of PAH patients and hypoxia-induced PASMCs compared with healthy volunteers and PASMCs under normoxia condition. MiR-223 is a target of circATP2B4, and the effects of circATP2B4 silencing on PASMCs were overturned by the transfection of anti-miR-223. ATR is a functional target of miR-223, and miR-223 inhibited the proliferation and migration while accelerated the apoptosis of PASMCs through targeting and down-regulating ATR. CircATP2B4 could up-regulate the level of ATR through sponging miR-223 in PSAMCs. CONCLUSION: CircATP2B4 potentiated hypoxia-induced proliferation and migration of PASMCs through the miR-223/ATR axis. Restoration of the level of miR-223 might be an effective therapeutic method for the treatment of PAH.

Adenomyosis in mice resulting from mechanically or thermally induced endometrial-myometrial interface disruption and its possible prevention.

RESEARCH QUESTION: Do uterine procedures potentially disrupting the endometrial-myometrial interface (EMI) induce adenomyosis? DESIGN: Six prospective, randomized controlled experiments were conducted involving a total of 106 female BALB/c and 12 female C57BL/6 mice. The incidence of adenomyosis was evaluated in these two strains of mouse after mechanically induced EMI disruption (EMID), or thermally induced EMID using electrocoagulation of different intensities. Finally, the incidence was evaluated in mice that had received perioperative administration of aprepitant (an NK1R inhibitor), propranolol (a beta-blocker) or vehicle. Body weight, hot plate latency and grade of myometrial infiltration were evaluated. Histology, immunohistochemistry and histochemistry analyses were also performed. RESULTS: Mechanical injury to the EMI caused EMID. Adenomyosis developed in the majority of mice in the EMID groups 3 months after mechanically induced EMID but did not develop in the control group (83.3% in C57BL/6 mice, P = 0.015; 100% in BALB/c mice, P = 0.0002). With thermally induced EMID, adenomyosis was found in 30% of the EMID mice 10 weeks later, but the incidence increased to 66.7% if the extent of EMID damage was increased. In mice with perioperative administration of aprepitant or propranolol, the incidence of adenomyosis was reduced from 100% to 58.3% (both P = 0.00034). CONCLUSIONS: This study provides the first piece of experimental evidence that EMID resulting from iatrogenic uterine procedures can substantially increase the risk of developing adenomyosis, with the risk in proportion to the severity of disruption. More intriguingly, perioperative administration of an NK1R antagonist or beta-blocker significantly reduced the risk of developing adenomyosis.

Low dose of IL-2 combined with rapamycin restores and maintains the long-term balance of Th17/Treg cells in refractory SLE patients.

BACKGROUND: The development of Systemic lupus erythematosus (SLE) has been associated with the balance of Th17 and Treg cells. IL-2 and rapamycin can influence the populations of both Th17 and Treg cells. However, it is unclear whether low dose of IL-2 and rapamycin can relieve the symptoms of SLE patients and what is the mechanisms. In this study, we aim to analyze the effect of low dose of IL-2 plus rapamycin on the number of Tregs, Th17 cells and the ratio of Th17/Treg cells, as well as to evaluate its therapeutic efficacy in refractory SLE patients. RESULT: Fifty refractory SLE patients and 70 healthy controls were enrolled and followed up for 24 weeks. We found that compared with HC, the refractory SLE patients had a lower number of Tregs, a similar number of Th17 cells, but an increased ratio of Th17/Treg. After the treatment, the number of Tregs of the patients at 12th and 24th week was significantly increased. While the number of Th17 cells was unchanged, the ratio of Th17/Treg was significantly decreased at both 6 weeks and 24 weeks. After 6, 12 and 24 weeks of treatment, the SLEDAI score was significantly reduced. The prednison dosage at 6th,12th and 24th week post treatment was significantly decreased. CONCLUSION: Our results support that the reduction of Tregs and the imbalance of Th17/Treg cells were correlated with the occurrence and development of refractory SLE. Low dose of IL-2 combined with rapamycin was able to restore the number of Tregs and the balance of Th17/Treg cells. As a result, this approach was able to induce immune tolerance and promote disease remission, allowing for the reduction in prednisone dosage. TRIAL REGISTRATION: ChiCTR-IPR-16009451 Registration date: 2016/10/16.

Overexpression of Lnk in the Ovaries Is Involved in Insulin Resistance in Women With Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) progression involves abnormal insulin signaling. SH2 domain-containing adaptor protein (Lnk) may be an important regulator of the insulin signaling pathway. We investigated whether Lnk was involved in insulin resistance (IR). Thirty-seven women due to receive laparoscopic surgery from June 2011 to February 2012 were included from the gynecologic department of the Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University. Samples of polycystic and normal ovary tissues were examined by immunohistochemistry. Ovarian cell lines underwent insulin stimulation and Lnk overexpression. Expressed Lnk underwent coimmunoprecipitation tests with green fluorescent protein-labeled insulin receptor and His-tagged insulin receptor substrate 1 (IRS1), and their colocalization in HEK293T cells was examined. Ovarian tissues from PCOS patients with IR exhibited higher expression of Lnk than ovaries from normal control subjects and PCOS patients without IR; mainly in follicular granulosa cells, the follicular fluid and plasma of oocytes in secondary follicles, and atretic follicles. Lnk was coimmunoprecipitated with insulin receptor and IRS1. Lnk and insulin receptor/IRS1 locations overlapped around the nucleus. IR, protein kinase B (Akt), and ERK1/2 activities were inhibited by Lnk overexpression and inhibited further after insulin stimulation, whereas IRS1 serine activity was increased. Insulin receptor (Tyr1150/1151), Akt (Thr308), and ERK1/2 (Thr202/Tyr204) phosphorylation was decreased, whereas IRS1 (Ser307) phosphorylation was increased with Lnk overexpression. In conclusion, Lnk inhibits the phosphatidylinositol 3 kinase-AKT and MAPK-ERK signaling response to insulin. Higher expression of Lnk in PCOS suggests that Lnk probably plays a role in the development of IR.