UBXN1 promotes liver tumorigenesis by regulating mitochondrial homeostasis.

BACKGROUND: The maintenance of mitochondrial homeostasis is critical for tumor initiation and malignant progression because it increases tumor cell survival and growth. The molecular events controlling mitochondrial integrity that facilitate the development of hepatocellular carcinoma (HCC) remain unclear. Here, we report that UBX domain-containing protein 1 (UBXN1) hyperactivation is essential for mitochondrial homeostasis and liver tumorigenesis. METHODS: Oncogene-induced mouse liver tumor models were generated with the Sleeping Beauty (SB) transposon delivery system. Assessment of HCC cell growth in vivo and in vitro, including tumour formation, colony formation, TUNEL and FACS assays, was conducted to determine the effects of UBXN1 on HCC cells, as well as the involvement of the UBXN1-prohibitin (PHB) interaction in mitochondrial function. Coimmunoprecipitation (Co-IP) was used to assess the interaction between UBXN1 and PHB. Liver hepatocellular carcinoma (LIHC) datasets and HCC patient samples were used to assess the expression of UBXN1. RESULTS: UBXN1 expression is commonly upregulated in human HCCs and mouse liver tumors and is associated with poor overall survival in HCC patients. UBXN1 facilitates the growth of human HCC cells and promotes mouse liver tumorigenesis driven by the NRas/c-Myc or c-Myc/shp53 combination. UBXN1 interacts with the inner mitochondrial membrane protein PHB and sustains PHB expression. UBXN1 inhibition triggers mitochondrial damage and liver tumor cell apoptosis. CONCLUSIONS: UBXN1 interacts with PHB and promotes mitochondrial homeostasis during liver tumorigenesis.

Preparation of Ag@lignin nanotubes for the development of antimicrobial biodegradable films from corn straw.

Current environmental and energy issues have attracted considerable attention from industries, governments, and academia. Developing alternative diverse petrochemical-based plastics with biodegradable packaging materials from renewable resources is critical for ensuring both sustainability and safety. In this study, biodegradable films are fabricated from corn straw via a facile sol-gel process. Furthermore, these films are imbued with antimicrobial properties by coupling with silver@lignin nanotube hybrid antibacterial agents, formed via the in situ reduction of silver ions into elemental silver by lignin (mild reducing agent), followed by the self-assembly of lignin molecules into nanotubes assisted by an aqueous silver nitrate electrolyte solution. The developed antibacterial corn straw film exhibits strong mechanical and antibacterial properties, with a tensile strength and elongation at break of 68.7 MPa and 11.3 %, respectively, under optimum conditions and antibacterial activity against Escherichia coli and Staphylococcus aureus of 99.9 % and 97.2 %, respectively. The as-prepared corn straw films exhibit high hydrophobicity and ultraviolet resistance. The morphology, structure, and thermal properties of the corn straw films were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and thermogravimetric analysis. This study provides a straw-based biodegradable packaging film with antimicrobial properties.

Online advance respiration prediction model for percutaneous puncture robotics.

PURPOSE: Surgical robots have significant research value and clinical significance in the field of percutaneous punctures. There have been numerous studies on ultrasound-guided percutaneous surgical robots; however, addressing the respiratory compensation problem of deep punctures remains a significant obstacle. Herein we propose a robotic system for percutaneous puncture with respiratory compensation. METHODS: We proposed an online advance respiratory prediction model based on Bidirectional Gate Recurrent Unit (Bi-GRU) for the respiratory prediction requirements of surgical robot systems. By analyzing the main factors governing the accuracy of the respiratory motion prediction models, various parameters of the online advance prediction model were optimized. Subsequently, we integrated and developed ultrasound-guided percutaneous puncture robot software and a hardware platform to implement respiratory compensation, thus verifying the effectiveness and reliability of various key technologies in the system. RESULTS: The proposed respiratory prediction model has a significantly reduced update time, with an average root mean square error (RMSE) of less than 0.4 mm. This represents a reduction of ~ 20% compared to the online training long short-term memory(LSTM). By conducting puncture experiments based on a respiratory phantom, the average puncture error was 2.71 ± 0.65 mm and the average single-round puncture time was 65.00 ± 6.67 s. CONCLUSION: Herein we proposed and optimized an online training respiratory prediction network model based on Bi-GRU. The stability and reliability of this system are verified by conducting puncture experiments on a respiratory phantom.

Outward-oriented sites within clustered CTCF boundaries are key for intra-TAD chromatin interactions and gene regulation.

CTCF plays an important role in 3D genome organization by adjusting the strength of chromatin insulation at TAD boundaries, where clustered CBS (CTCF-binding site) elements are often arranged in a tandem array with a complex divergent or convergent orientation. Here, using Pcdh and HOXD loci as a paradigm, we look into the clustered CTCF TAD boundaries and find that, counterintuitively, outward-oriented CBS elements are crucial for inward enhancer-promoter interactions as well as for gene regulation. Specifically, by combinatorial deletions of a series of putative enhancer elements in mice in vivo or CBS elements in cultured cells in vitro, in conjunction with chromosome conformation capture and RNA-seq analyses, we show that deletions of outward-oriented CBS elements weaken the strength of long-distance intra-TAD promoter-enhancer interactions and enhancer activation of target genes. Our data highlight the crucial role of outward-oriented CBS elements within the clustered CTCF TAD boundaries in developmental gene regulation and have interesting implications on the organization principles of clustered CTCF sites within TAD boundaries.

Preparation of Bio-Foam Material from Steam-Exploded Corn Straw by In Situ Esterification Modification.

In this work, we engineered a corn-straw-based bio-foam material under the inspiration of the intrinsic morphology of the corn stem. The explosion pretreatment was applied to obtain a fibrillated cellulose starting material rich in lignin. The in situ esterification of cellulose was adopted to improve the cross-linking network of the as-developed foam bio-material. The esterification of lignin was observed in the same procedure, which provides a better cross-linking interaction. The esterified corn-straw-derived bio-foam material showed excellent elastic resilience performance with an elastic recovery ratio of 83% and an elastic modulus of 20 kPa. Meanwhile, with surface modification by hexachlorocyclotriphosphazene-functionalized lignin as the flame retardant (Lig-HCCP), the as-obtained bio-foam material demonstrated quite a good flame retardancy (with 27.3% of the LOI), as well as a heat insulation property. The corn-straw-derived bio-foam material is prospected to be a potential substitution packaging material for widely used petroleum-derived products. This work provides a new value-added application of the abundant agricultural straw biomass resources.

Method for Carotid Artery 3-D Ultrasound Image Segmentation Based on CSWin Transformer.

Precise segmentation of carotid artery (CA) structure is an important prerequisite for the medical assessment and detection of carotid plaques. For automatic segmentation of the media-adventitia boundary (MAB) and lumen-intima boundary (LIB) in 3-D ultrasound images of the CA, a U-shaped CSWin transformer (U-CSWT) is proposed. Both the encoder and decoder of the U-CSWT are composed of hierarchical CSWT modules, which can capture rich global context information in the 3-D image. Experiments were performed on a 3-D ultrasound image data set of the CA, and the results indicate that the U-CSWT performs better than other convolutional neural network (CNN)-based and CNN-transformer hybrid methods. The model yields Dice coefficients of 94.6 ± 3.0% and 90.8 ± 5.1% for the MAB and LIB in the common carotid artery (CCA) and 92.9 ± 4.9% and 89.6 ± 6.2% for MAB and LIB in the bifurcation, respectively. Our U-CSWT is expected to become an effective method for automatic segmentation of 3-D ultrasound images of CA.

Robotic system for accurate percutaneous puncture guided by 3D-2D ultrasound.

PURPOSE: Ultrasound (US)-guided robotic systems can reduce the reliance on the experience and skills of surgeons and enable automatic and accurate percutaneous puncture. Two-dimensional (2D) and three-dimensional (3D) US guidance have various advantages and disadvantages. The planned puncture path in the US data directly affects the puncture quality and tissue injury risk. It is difficult to define the optimal path in 2D US images and achieve accurate and safe puncture under the guidance of 3D US volume. This study aims to propose a robotic system guided by 3D-2D US to realize accurate and safe percutaneous puncture. METHODS: We proposed a 3D-2D US-guided percutaneous puncture robotic system by integrating a 3D US scanning robotic system and a 2D US-guided puncture robotic system. The optimal spatial puncture path that targets the lesion and avoids other important tissues was determined in the 3D US volume reconstructed through robotic US scanning. Thereafter, the puncture robot was placed at the puncture site determined according to the planned path. The optimal path was mapped to the 2D US image taken at the puncture site. Finally, the 2D US image and puncture path were used to guide the robot in performing an accurate and safe percutaneous puncture. RESULTS: The proposed robotic system based on the guidance of 3D-2D US exhibits the advantages of both 3D US and 2D US to improve the accuracy of percutaneous puncture and reduce the risk of tissue injury. The experimental results of phantom puncture demonstrate that the mean puncture accuracy of the system is 1.09 ± 0.35 mm, and the puncture success rate with single needle insertion is 100%. CONCLUSION: A percutaneous puncture robotic system based on 3D-2D US guidance was proposed and tested successfully. The experimental results demonstrate the feasibility of the proposed system for achieving accurate and safe robotic percutaneous puncture.

Design and implementation of a surgical planning system for robotic assisted mandible reconstruction with fibula free flap.

PURPOSE: Free fibula flap is the gold standard for the treatment of mandibular defects. However, the existing preoperative planning protocol is cumbersome to execute, costly to learn, and poorly collaborative with the robot-assisted cutting of the fibular osteotomy plane. METHODS: A surgical planning system for robotic assisted mandibular reconstruction with fibula free flap is proposed in this study. A fibular osteotomy planning algorithm is presented so that the virtual surgical planning of the fibular osteotomy segments can be obtained automatically with selected mandibular anatomical landmarks. The planned osteotomy planes are then converted into the motion path of the robotic arm, and the automatic fibula osteotomy is completed under optical navigation. RESULTS: Surgical planning was performed on 35 patients to verify the feasibility of our system's virtual surgical planning module, with an average time of 13 min. Phantom experiments were performed to evaluate the reliability and stability of this system. The average distance and angular deviations of the osteotomy planes are 1.04 ± 0.68 mm and 1.56 ±1.10°, respectively. CONCLUSIONS: Our system can achieve not only precise and convenient preoperative planning, but also safe and reliable osteotomy trajectory. The clinical applications of our system for mandibular reconstruction surgery are expected soon.

Paternal nicotine exposure promotes hepatic fibrosis in offspring.

Paternal nicotine exposure can alter phenotypes in future generations. The aim of this study is to explore whether paternal nicotine exposure affects the hepatic repair to chronic injury which leads to hepatic fibrosis in offspring. Our results demonstrate that nicotine down regulates mmu-miR-15b expression via the hyper-methylation on its CpG island shore region in the spermatozoa. This epigenetic modification imprinted in the liver of the offspring. The decreased mmu-miR-15b promotes the expression of Wnt4 and activates the Wnt pathway in the offspring mice liver. The activation of the Wnt pathway improves the activation and proliferation of hepatic stellate cells (HSCs) leading to liver fibrosis. Moreover, the Wnt pathway promotes the activation of the TGF-ß pathway and the two pathways cooperate to promote the transcription of extracellular matrix (ECM) genes. In conclusion, this study found that nicotine promotes hepatic fibrosis in the offspring via the activation of Wnt pathway by imprinting the hyper-methylation of mmu-miR-15b.

Paternal nicotine exposure induces hyperactivity in next-generation via down-regulating the expression of DAT.

Many substances in cigarette smoke can induce changes in DNA methylation. Our previous studies have confirmed paternal nicotine exposure causes hyperactivity in the offspring via mmu-miR-15b. The main aim of the present study is to explore the molecular mechanism underlying the cross-generation effects of paternal nicotine exposure more comprehensively. The male C57BL/6 mice were exposed to 2 mg/kg/d nicotine for 5 weeks, and then mated with wild-type females. The offspring male mice were subjected to behavioral tests at 8 weeks after birth. The results suggested that, paternal nicotine exposure led to hyperactivity in the offspring. An analysis of the changes in DNA methylation revealed that nicotine exposure induced a rise in the total DNA methylation level of Dat in murine spermatozoa, and the hyper-methylation could imprint in the brains of the offspring mice. Then these epigenetic modifications reduced the expression of DAT in the brain of the offspring, resulting in a rise in the level of extracellular dopamine. The activation of D2 receptors caused the dephosphorylation of AKT, which led to increased activation of GSK3α/ß, and ultimately caused hyperactivity in the offspring mice. Further, in wild-type mice, injection of DAT inhibitors simulated this hyperactive phenotype, while the injection of D2s inhibitors reversed the hyperactivity of the offspring caused by paternal nicotine exposure. In conclusion, all results indicated that paternal nicotine exposure could induce hyperactivity in the offspring via the hyper-methylation of Dat. Consequently, Dat may be one of the genes that mediate the cross-generation effects of nicotine besides mmu-mmiR-15b.

RNA profile of control and nicotine treated Murine Leydig single cell represented in TPM data.

Data provided in this article is RNA profile represented in RPKM and RPKM based TPM value for the research article titled Nicotine inhibits Murine Leydig cell differentiation and maturation via regulating Hedgehog signal pathway Jiajie et al., 2019. Nicotine treatment changes the RNA profile of Murine Leydig cells. RNA of 12 control group Leydig cells and 12 nicotine treated Leydig cells are sequenced and the data of 29943 genes are achieved. The information of the gene symbol, gene description, gene type, position and transcript length are provided.

Nicotine inhibits murine Leydig cell differentiation and maturation via regulating Hedgehog signal pathway.

Nicotine, the main toxic substance in cigarette smoke, significantly reduced the differentiation and maturation ratio of Leydig cell in murine testes. To investigate the underlying mechanism, C57BL/6J mice were divided into control (CT) and nicotine treated (NT) groups. Next generation RNA sequencing and bio-informatics analysis were carried out to analysis the effects of nicotine on the RNA profile of Leydig cells. Expression level of 7 pathways remarkably changed after nicotine treatment. As the positive regulating pathway of Leydig cell differentiation, Hedgehog signaling pathway was found among these pathways. PTCH1 and ß-TrCP were down-regulated in nicotine treated mice Leydig cells, while GSK3ß, Gli2 and Gli2 fragments increased significantly. Nicotine stimulated the destabilization of Gli2 via ß-TrCP induced ubiquitination and degradation. Gli2 was phosphorylated by up-expressed GSK3ß during this process. Destabilization of Gli2 reduced the activation rate of target genes of Hedgehog signaling pathway such as Ptch1. The differentiation of Leydig cell positively regulated by Hh pathway was thus inhibited by nicotine exposure. Consequently, the male reproduction process powered by Leydic cell-mediated androgen secretion was thus influenced. In conclusion, we find that nicotine inhibits murine Leydig cell differentiation and maturation via regulating Hedgehog signal pathway.

Prohibitin 2-mediated mitophagy attenuates renal tubular epithelial cells injury by regulating mitochondrial dysfunction and NLRP3 inflammasome activation.

Accumulating evidence demonstrates that mitochondrial dysfunction and inflammasome activation play a critical role in the pathogenesis of renal tubular injury through the production of reactive oxygen species and cytokines. Prohibitin 2 (PHB2) is a newly identified intracellular receptor of mitophagy (a type of autophagy) that mediates selective removal of damaged mitochondria, and it could possibly play a renoprotective role in kidney disease. In this study, we confirmed that autophagy is activated in tubular epithelial cells treated with angiotensin II and that inhibition of autophagy results in tubular cell injury. Strikingly, PHB2 knockdown reduced the level of mitophagy and augmented cell death, while overexpression of PHB2 provided protection against pyrin domain-containing protein 3 (NLRP3)-induced inflammatory pathways through amelioration of mitochondrial dysfunction. Our research is the first to experimentally demonstrate the role of PHB2 in renal proximal tubular cells and thereby to provide a better understanding of how autophagy modulates inflammation in renal tubules. These data highlight PHB2 as a therapeutic target in the future treatment of CKD.

Emission of sulfur dioxide from polyurethane foam and respiratory health effects.

Recently, health damage to children exposed to synthetic polyurethane (PU) running tracks has aroused social panic in China. Some possible toxic volatiles may be responsible for these damages. However, the exact cause remains unclear. We have detected a low concentration of sulfur dioxide (SO2; 1.80-3.30 mg/m3) on the surface of the PU running track. Surprisingly, we found that SO2 was generated from the PU running track, and even such a low concentration of SO2 could induce severe lung inflammation with hemorrhage, inflammatory cell infiltration, and inflammatory factor secretion in mice after 2-week exposure. Prolonged exposure (5 weeks) to the SO2 caused chronic pulmonary inflammation and pulmonary fibrosis in the mice. Peripheral hemogram results showed that platelet concentration increased significantly in the SO2 group compared to that in the control group, and the proportion of blood neutrophils and monocytes among total leukocytes was more imbalanced in the SO2 group (16.6%) than in the control group (8.0%). Further histopathology results of sternal marrow demonstrated that hematopoietic hyperplasia was severely suppressed with increased reticular stroma and adipocytes under SO2 exposure. These data indicate that a low concentration of SO2 generated spontaneously from PU running track outdoors as a secondary product is still harmful to health, as it impairs the respiratory system, hematopoiesis, and immunologic function. This indicates that the low-concentration SO2 could be a major cause of diseases induced by air pollution, such as chronic obstructive pulmonary disease.

Nicotine induced autophagy of Leydig cells rather than apoptosis is the major reason of the decrease of serum testosterone.

A new report has shown that nicotine exposure can decrease serum testosterone by apoptosis in Leydig cells; however, in our previous studies, we have almost never observed apoptosis there. The purpose of this study is to ensure whether apoptosis or autophagy in Leydig cells occurred. Our results confirmed again that the concentration of testosterone in the sera of nicotine-treated mice statistically decreased (P < 0.05). Furthermore, the data of single cell transcriptome indicated that the expression of autophagy-related genes was increased after nicotine exposure. Likewise, chemical and immune-histological staining demonstrated that autophagy of the Leydig cells increased after nicotine treatment rather than apoptosis. Apoptosis mainly exists in spermatids. Further, the expression of autophagy-related genes, such as Beclin1 and LC3, were up-regulated after nicotine exposure (P < 0.05). Additionally, the data of transmission electron microscopy showed more autophagosomes in the Leydig cells of the nicotine-exposed groups than the cells of the control groups. Moreover, immunofluorescent staining of LC3 in the TM3 Leydig cell line indicated that rapamycin and nicotine exposure up-regulates the autophagy phenotype/process and down-regulates their testosterone synthesis. In addition, the methylation level of the promoter region of TCL1 is increased in the nicotine-treated group compared to the control group, consequently decreasing the expression of TCL1. In conclusion, the autophagy in Leydig cells induced by nicotine, which is set by the hyper-methylation of the TCL1 promoter region via the TCL1-mTOR-autophagy signaling pathway.

Maternal nicotine exposure has severe cross-generational effects on offspring behavior.

Our previous studies showed that paternal nicotine exposure can lead to hyperactivity in the offspring. Nevertheless, the cross-generational effects of maternal and biparental nicotine exposure remain unclear. In this study, female and male mice were exposed respectively by nicotine before pregnancy. The maternal pre-pregnancy nicotine exposure led to depression-like behaviors in the F1 offspring. However, after biparental pre-pregnancy nicotine exposure, seventy percentage of the offspring exhibited a depressive phenotype while 20% were hyperactive, and the remaining exhibited no obvious abnormal behavior. The cross-generational effects appeared to be mediated via disruption of the balance between GSK3 and p-GKS3 by nicotine. These results suggested that pre-pregnancy nicotine exposure can induce alterations in the behavior of the offspring, and the cross-generational effects of maternal nicotine exposure were particularly serious.

Paternal nicotine exposure defines different behavior in subsequent generation via hyper-methylation of mmu-miR-15b.

The neurobehavioral effects of paternal smoking and nicotine use have not been widely reported. In the present study, nicotine exposure induced depression in the paternal generation, but reduced depression and promoted hyperactivity in F1 offspring. While this intergenerational effect was not passed down to the F2 generation. Further studies revealed that nicotine induced the down-regulation of mmu-miR-15b expression due to hyper-methylation in the CpG island shore region of mmu-miR-15b in both the spermatozoa of F0 mice and the brains of F1 mice. As the target gene of mmu-miR-15b, Wnt4 expression was elevated in the thalamus of F1 mice due to the inheritance of DNA methylation patterns from the paternal generation. Furthermore, the increased expression of Wnt4 elevated the phosphorylation level of its downstream protein GSK-3 through the canonical WNT4 pathway which involved in the behavioral alterations observed in F1 mice. Moreover, in vivo stereotaxic brain injections were used to induce the overexpression of mmu-miR-15b and WNT4 and confirm the neurobehavioral effects in vitro. The behavioral phenotype of the F1 mice resulting from paternal nicotine exposure could be attenuated by viral manipulation of mmu-miR-15b in the thalamus.

Evaluation of the C-domain of heparanase during AGE-induced macrophage inflammatory response.

Diabetic vasculopathy is intensified by macrophage inflammation caused by advanced glycation end products (AGEs). Heparanase (HPA) is a unique endoglycosidase, which cleaves heparan sulfate proteoglycans (HSPGs) including syndecan-1 (Syn-1) to further stimulate macrophage cell migration and inflammation. The present study was planned to evaluated the role of C-domain (if any) of HPA in AGE inflammatory response in macrophages. Cell viability was assessed using MTT assay, migration assay, ELISA for tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) levels, mRNA expression by RT-PCR and heparan degrading enzyme assay for HPA activity. In the present study, we found that pretreatment with anti-HPA antibody, which recognizes the C-domain of HPA inhibited macrophage migration, secretion of IL-1ß and TNF-α as well as decreased HPA enzymatic activity and increased Syn-1 protein expression in AGE-induced macrophages. Compared with anti-HPA antibody pretreatment, co-pretreatment with anti-HPA plus Syn-1 antibodies promoted macrophage migration, and secretion of IL-1ß and TNF-α significantly in AGE-induced macrophages. In addition, pretreatment with anti-HPA or anti-HPA plus Syn-1 antibodies did not markedly change the mRNA levels of IL-1ß and TNF-α concentration AGE-treated macrophages. The results showed that C-domain of HPA mediates AGE-induced macrophage migration and inflammatory cytokine release via Syn-1 protein expression. Furthermore, C-domain of HPA may have a key role in diabetic vascular complication-associated inflammatory response.

Nicotine facilitates VSMC dysfunction through a miR-200b/RhoGDIA/cytoskeleton module.

Nicotine can induce the abnormal migration and proliferation of vascular smooth muscle cells (VSMCs). We have previously shown that cytoskeletal proteins and RhoGDIA, a negative regulator of the Rho GTPase pathway, are involved in the nicotine-induced dysfunction of VSMCs. Here, we found that nicotine can activate the Rho GTPase pathway and induce the synthesis of the cytoskeletal proteins in VSMCs through the activation of intracellular downstream signaling pathways, including targets such as MYPT1, PAK1 and PI3K/AKT. Upon nicotine treatment, the mRNA level of RhoGDIA is increased but protein level is decreased both in vitro and in vivo, which suggested a mechanism of post-translational regulation. By the dual luciferase reporter assay, we identified the microRNA-200b (miR-200b) as a modulator of the behavioural changes of VSMCs in response to nicotine through targeting RhoGDIA directly. Introducing miR-200b inhibitors into cultured VSMCs significantly attenuated cell proliferation and migration. Additionally, we found that hypomethylation in the CpG island shore region of miR-200b was responsible for the nicotine-induced miR-200b up-regulation in VSMCs. The study demonstrates that nicotine facilitates VSMC dysfunction through a miR-200b/RhoGDIA/cytoskeleton module through the hypomethylation of miR-200b promoter and suggests that epigenetic modifications may play an important role in the pathological progression.

Nicotine induces Nme2-mediated apoptosis in mouse testes.

In mouse testes, germ cell apoptosis can be caused by cigarette smoke and lead to declining quality of semen, but the exact molecular mechanisms remain unclear. To evaluate the effects of nicotine exposure on apoptosis during spermatogenesis, we first constructed a nicotine-treated mouse model and detected germ cell apoptosis activity in the testes using the TUNEL method. Then we analyzed the variation of telomere length and telomerase activity by real-time PCR and TRAP-real-time PCR, respectively. Further, we investigated a highly expressed gene, Nme2, in mouse testes after nicotine treatment from our previous results, which has close correlation with the apoptosis activity predicted by bioinformatics. We performed NME2 overexpression in Hela cells to confirm whether telomere length and telomerase activity were regulated by the Nme2 gene. Finally, we examined methylation of CpG islands in the Nme2 promoter with the Bisulfite Sequencing (BSP) method. The results showed that apoptosis had increased significantly, and then telomerase activity became weak. Further, telomere length was shortened in the germ cells among the nicotine-treated group. In Hela cells, both overexpression of the Nme2 gene and nicotine exposure can suppress the activity of telomerase activity and shorten telomere length. BSP results revealed that the Nme2 promoter appeared with low methylation in mouse testes after nicotine treatment. We assume that nicotine-induced apoptosis may be caused by telomerase activity decline, which is inhibited by the up expression of Nme2 because of its hypomethylation in mouse germ cells.