Nicotine induces senescence in spermatogonia stem cells by disrupting homeostasis between circadian oscillation and rhythmic mitochondrial dynamics via the SIRT6/Bmal1 pathway

Infertility is intricately linked with alterations in circadian rhythms along with physiological decline and stem cell senescence. Yet, the direct involvement of circadian mechanisms in nicotine-induced injury to the testes, especially the senescence of spermatogonia stem cells (SSCs), is not well comprehended. This study revealed that nicotine exposure induced testis injury by triggering SSCs senescence along with the upregulation of senescence marker genes and senescence-associated secretory phenotype components. Moreover, nicotine treatment caused mitochondrial hyper-fusion, increased oxidative stress, and DNA damage. Exposure to nicotine was found to suppress the expression of sirtuin 6 (SIRT6), which accelerated the senescence of spermatogonia stem cells (SSCs). This acceleration led to increased acetylation of brain and muscle ARNT-like protein (Bmal1), consequently reducing the expression of Bmal1 protein. Conversely, the overexpression of Bmal1 alleviated mitochondrial hyper-fusion and senescence phenotypes induced by nicotine. Overall, this study unveiled a novel molecular mechanism behind nicotine-induced disorders in spermatogenesis and highlighted the SIRT6/Bmal1 regulatory pathway as a potential therapeutic target for combating nicotine-associated infertility.

The role of ferroptosis mediated by Bmal1/Nrf2 in nicotine -induce injury of BTB integrity

Nicotine has shown the toxic effects on male reproductive system, and testicular damage is associated with ferroptosis, which is a non-apoptotic regulated cell death driven by iron-dependent lipid peroxidation. However, the role of nicotine on ferroptosis of testicular cells is largely elusive. In the present study, we showed that nicotine destroyed blood-testis barrier (BTB) by interfering with the circadian rhythm of BTB-related factors (ZO-1, N-Cad, Occludin and CX-43) and induced ferroptosis, as reflected via increased clock-control levels of lipid peroxide and decreased ferritin and GPX4, which involved in the circadian. Inhibition of ferroptosis with Fer-1 alleviated nicotine-induced injury of BTB and impaired sperm in vivo. Mechanically, we uncover that the core molecular clock protein, Bmal1, regulates the expression of Nrf2 via direct E-box binding to its promoter to regulate its activity, and nicotine decreases the transcription of Nrf2 through Bmal1 and inactivates Nrf2 pathway and its downstream antioxidant gene, which leads to the imbalance of redox state and ROS accumulation. Intriguingly, nicotine induced lipid peroxidation and subsequent ferroptosis by Bmal1-mediated Nrf2. In conclusion, our study reveals a clear role for the molecular clock in controlling Nrf2 in testis to mediate the ferroptosis induced by nicotine. These findings provide a potential mechanism to prevent smoking and/or cigarette smoke-induced male reproductive injury.

MAGED4B Promotes Glioma Progression via Inactivation of the TNF-α-induced Apoptotic Pathway by Down-regulating TRIM27 Expression

MAGED4B belongs to the melanoma-associated antigen family; originally found in melanoma, it is expressed in various types of cancer, and is especially enriched in glioblastoma. However, the functional role and molecular mechanisms of MAGED4B in glioma are still unclear. In this study, we found that the MAGED4B level was higher in glioma tissue than that in non-cancer tissue, and the level was positively correlated with glioma grade, tumor diameter, Ki-67 level, and patient age. The patients with higher levels had a worse prognosis than those with lower MAGED4B levels. In glioma cells, MAGED4B overexpression promoted proliferation, invasion, and migration, as well as decreasing apoptosis and the chemosensitivity to cisplatin and temozolomide. On the contrary, MAGED4B knockdown in glioma cells inhibited proliferation, invasion, and migration, as well as increasing apoptosis and the chemosensitivity to cisplatin and temozolomide. MAGED4B knockdown also inhibited the growth of gliomas implanted into the rat brain. The interaction between MAGED4B and tripartite motif-containing 27 (TRIM27) in glioma cells was detected by co-immunoprecipitation assay, which showed that MAGED4B was co-localized with TRIM27. In addition, MAGED4B overexpression down-regulated the TRIM27 protein level, and this was blocked by carbobenzoxyl-L-leucyl-L-leucyl-L-leucine (MG132), an inhibitor of the proteasome. On the contrary, MAGED4B knockdown up-regulated the TRIM27 level. Furthermore, MAGED4B overexpression increased TRIM27 ubiquitination in the presence of MG132. Accordingly, MAGED4B down-regulated the protein levels of genes downstream of ubiquitin-specific protease 7 (USP7) involved in the tumor necrosis factor-alpha (TNF-α)-induced apoptotic pathway. These findings indicate that MAGED4B promotes glioma growth via a TRIM27/USP7/receptor-interacting serine/threonine-protein kinase 1 (RIP1)-dependent TNF-α-induced apoptotic pathway, which suggests that MAGED4B is a potential target for glioma diagnosis and treatment.

Emerging roles of TRIM27 in cancer and other human diseases

As a member of the TRIM protein family, TRIM27 is a RING-mediated E3 ubiquitin ligase that can mark other proteins for degradation. Its ubiquitination targets include PTEN, IκBα and p53, which allows it to regulate many signaling pathways to exert its functions under both physiological and pathological conditions, such as cell proliferation, differentiation and apoptosis. During the past decades, TRIM27 was reported to be involved in many diseases, including cancer, lupus nephritis, ischemia-reperfusion injury and Parkinson’s disease. Although the research interest in TRIM27 is increasing, there are few reviews about the diverse roles of this protein. Here, we systematically review the roles of TRIM27 in cancer and other human diseases. Firstly, we introduce the biological functions of TRIM27. Next, we focus on the roles of TRIM27 in cancer, including ovarian cancer, breast cancer and lung cancer. At the same time, we also describe the roles of TRIM27 in other human diseases, such as lupus nephritis, ischemia-reperfusion injury and Parkinson’s disease. Finally, we discuss the future directions of TRIM27 research, especially its potential roles in tumor immunity.

TRIM27 contributes to glomerular endothelial cell injury in lupus nephritis by mediating the FoxO1 signaling pathway

Tripartite motif-containing 27 (TRIM27) belongs to the triple motif (TRIM) protein family, which plays a role in a variety of biological activities. Our previous study showed that the TRIM27 protein was highly expressed in the glomerular endothelial cells of patients suffering from lupus nephritis (LN). However, whether TRIM27 is involved in the injury of glomerular endothelial cells in lupus nephritis remains to be clarified. Here, we detected the expression of the TRIM27 protein in glomerular endothelial cells in vivo and in vitro. In addition, the influence of TRIM27 knockdown on endothelial cell damage in MRL/lpr mice and cultured human renal glomerular endothelial cells (HRGECs) was explored. The results revealed that the expression of TRIM27 in endothelial cells was significantly enhanced in vivo and in vitro. Downregulating the expression of TRIM27 inhibited the breakdown of the glycocalyx and the injury of endothelial cells via the FoxO1 pathway. Moreover, HRGECs transfected with the WT-FoxO1 plasmid showed a reduction in impairment caused by LN plasma. Furthermore, suppression of the protein kinase B (Akt) pathway could attenuate damage by mediating the expression of TRIM27. Thus, the present study showed that TRIM27 participated in the injury of glomerular endothelial cells and served as a potential therapeutic target for the treatment of lupus nephritis.

The amelioration of nicotine-induced reproductive impairment in male mouse by Sambucus ebulus L. fruit extract

Nicotine as a toxic agent in cigarette smoke impairs the reproductive system. Sambucus ebulus extract (SEE) is shown to have some beneficial effects such as antioxidant properties. The aim of this study was to evaluate the effects of SEE on the hormones of the pituitary-gonadal axis, lipid peroxidation index, antioxidant enzymes, spermatogenesis, and epididymal sperm parameters in male mice treated with nicotine. Adult male mice were divided into five groups; A: normal saline, B: 1 mg/kg nicotine, C: 1 mg/kg nicotine and 10 mg/kg SEE, D: 1 mg/kg nicotine and 50 mg/kg SEE, D: 1 mg/kg nicotine and 100 mg/kg SEE. Treatments lasted for 35 days. The spermicidal activity of SEE was tested in vitro. Sperm count, motility and morphology were assessed for fertility. Serum testosterone, prolactin and luteinizing hormone (LH) were measured, using ELISA. Serum malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) activity were measured, using colorimetric assays. Spermatogenesis was evaluated by Johnsen’s score and morphometry in histological slides. SEE at different doses did not have any spermicidal activity. Sperm parameters were reduced in the nicotine-treated group, compared with controls (P<0.01). Nicotine reduced testosterone and LH levels (P<0.01) and increased prolactin (P<0.01). A hike in MDA and a reduction in SOD activity without change on CAT, were observed in the nicotine group. Nicotine caused hypospermatogenesis. SEE improved most of the above-mentioned parameters, especially in the doses of 50 and 100 mg/kg. Beneficial effects of SEE in the doses of 50 and 100 mg/kg on male reproduction impairment, induced by nicotine might be partly attributed to the reduction of oxidative stress and changes in the hormones of the pituitary-gonadal axis.

Tripartite Motif-Containing 27 Attenuates Liver Ischemia/Reperfusion Injury by Suppressing Transforming Growth Factor β-Activated Kinase 1 (TAK1) by TAK1 Binding Protein 2/3 Degradation

BACKGROUND AND AIMS

Hepatic ischemia-reperfusion (I/R) injury, which mainly involves inflammatory responses and apoptosis, is a common cause of organ dysfunction in liver transplantation (LT). As a critical mediator of inflammation and apoptosis in various cell types, the role of tripartite motif-containing (TRIM) 27 in hepatic I/R injury remains worthy of study.

APPROACH AND RESULTS

This study systemically evaluated the putative role of TRIM27/transforming growth factor β-activated kinase 1 (TAK1)/JNK (c-Jun N-terminal kinase)/p38 signaling in hepatic I/R injury. TRIM27 expression was significantly down-regulated in liver tissue from LT patients, mice subjected to hepatic I/R surgery, and hepatocytes challenged by hypoxia/reoxygenation (H/R) treatment. Subsequently, using global Trim27 knockout mice (Trim27-KO mice) and hepatocyte-specific Trim27 transgenic mice (Trim27-HTG mice), TRIM27 functions to ameliorate liver damage, reduce the inflammatory response, and prevent cell apoptosis. In parallel in vitro studies, activating TRIM27 also prevented H/R-induced hepatocyte inflammation and apoptosis. Mechanistically, TRIM27 constitutively interacted with the critical components, TAK1 and TAK1 binding protein 2/3 (TAB2/3), and promoted the degradation of TAB2/3, leading to inactivation of TAK1 and the subsequent suppression of downstream JNK/p38 signaling.

CONCLUSIONS

TRIM27 is a key regulator of hepatic I/R injury by mediating the degradation of TAB2/3 and suppression of downstream TAK1-JNK/p38 signaling. TRIM27 may be a promising approach to protect the liver against I/R-mediated hepatocellular damage in transplant recipients.

TRIM27 acts as an oncogene and regulates cell proliferation and metastasis in non-small cell lung cancer through SIX3-β-catenin signaling

The Wnt/β-catenin pathway plays vital roles in diverse biological processes, including cell differentiation, proliferation, migration, and insulin sensitivity. A recent study reported that the DNA-binding transcriptional factor SIX3 is essential during embryonic development in vertebrates and capable of downregulating target genes of the Wnt/β-catenin pathway in lung cancer, indicating negative regulation of Wnt/β-catenin activation. However, regulation of the SIX3-Wnt/β-catenin pathway axis remains unknown. We measured the expression of TRIM27 and SIX3 as well as investigated whether there was a correlation between them in lung cancer tissue samples. Herein, we found that the E3 ubiquitin ligase, TRIM27, ubiquitinates, and degrades SIX3. TRIM27 induces non-small cell lung cancer (NSCLC) cell proliferation and metastasis, and the expression of β-catenin, S100P, TGFB3, and MMP-9 were significantly inhibited by SIX3. Furthermore, XAV939 is a selective β-catenin-mediated transcription inhibitor that inhibited TRIM27- and SIX3-mediated NSCLC cell proliferation, migration, and invasion. Clinically, lung tissue samples of cancer patients showed increased TRIM27 expression and decreased SIX3 expression. Taken together, these data demonstrate that TRIM27 acts as an oncogene regulating cell proliferation and metastasis in NSCLC through SIX3-β-catenin signaling.

Giardia duodenalis induces extrinsic pathway of apoptosis in intestinal epithelial cells through activation of TNFR1 and K63 de-ubiquitination of RIP1 in vitro

Giardia duodenalis is one of main causative agents of diarrhea that affects the health of millions of people on a global scale per year. It has been clear that attachment of G. duodenalis trophozoites to intestinal epithelium cells (IECs) can induce cell death, while the underlying cellular and molecular mechanisms remain to be explored. It was shown in this study that treatment of Caco-2 cells with Giardia trophozoites could result in reduced cell viability. RNA sequencing analysis demonstrated that expressions of many apoptosis-related genes and some deubiquitinase genes displayed marked changes in trophozoite-treated cells. Trophozoites activated the death-signaling receptor TNFR1 on the IEC surface and caspase-3/8 (CASP3/8) signaling pathways in Caco-2 cells. K63 ubiquitination level of RIP1 was reduced upon stimulation with trophozoites, in parallel, the expressions of deubiquitinases CYLD and A20 were increased. The caspase inhibitor Q-VD-OPH could rescue trophozoite-induced cell apoptosis. Likewise, TNFR1, CYLD, and A20 silencing decreased the levels of cleaved CASP3/8 in trophozoite-treated cells and reversed the pro-apoptosis induction effect of trophozoites. These data suggest that Giardia trophozoite stimulation can activate CASP3/8 signaling pathways via activation of TNFR1 and K63 de-ubiquitination of RIP1 caused by up-regulated expressions of CYLD and A20, and promote Caco-2 cell apoptosis. The present study deepens our understanding of the mechanism of interaction between Giardia and IECs.

Impact of nicotine, alcohol, and cocaine exposure on germline integrity and epigenome

Converging evidence suggests that parental exposure to drugs of abuse can affect offspring phenotypes. The impacts of drug abuse on germ cell quality may mediate multigenerational and transgenerational inheritance, although biological pathways underlying this mode of inheritance are not yet characterized. Germline epigenetic marks are modified by drug exposure and have emerged as promising mechanistic candidates in recent work. Drug exposure also impacts overall germline integrity and reproductive functioning, although the role of these consequences in multi/transgenerational inheritance is unclear. This review synthesizes literature on effects of exposure to alcohol, cocaine, and nicotine on the germline with a focus on epigenetic modifications following drug exposure and broader impacts on germline integrity and reproductive functioning. We discuss potential interactions between reproductive functioning, germline integrity, and germline epigenome/transcriptome in pathways underlying multi/transgenerational inheritance. We find that existing data may support independent or interactive contributions of these germline impacts on offspring phenotypes in a manner that may mediate multi/transgenerational inheritance.

Smoking and DNA methylation: Correlation of methylation with smoking behavior and association with diseases and fetus development following prenatal exposure

Among epigenetic mechanisms, DNA methylation has been widely studied with respect to many environmental factors. Smoking is a common factor which affects both global and gene-specific DNA methylation. It is supported that smoking directly affects DNA methylation, and these effects contribute to the development and progression of various diseases, such as cancer, lung and cardiovascular diseases and male infertility. In addition, prenatal smoking influences the normal development of the fetus via DNA methylation changes. The DNA methylation profile and its smoking-induced alterations helps to distinguish current from former smokers and non-smokers and can be used to predict the risk for the development of a disease. This review summarizes the DNA methylation changes induced by smoking, their correlation with smoking behavior and their association with various diseases and fetus development.