PTEN deficiency induces an extrahepatic cholangitis-cholangiocarcinoma continuum via aurora kinase A in mice.

BACKGROUND & AIMS: The PTEN-AKT pathway is frequently altered in extrahepatic cholangiocarcinoma (eCCA). We aimed to evaluate the role of PTEN in the pathogenesis of eCCA and identify novel therapeutic targets for this disease. METHODS: The Pten gene was genetically deleted using the Cre-loxp system in biliary epithelial cells. The pathologies were evaluated both macroscopically and histologically. The characteristics were further analyzed by immunohistochemistry, reverse-transcription PCR, cell culture, and RNA sequencing. Some features were compared to those in human eCCA samples. Further mechanistic studies utilized the conditional knockout of Trp53 and Aurora kinase A (Aurka) genes. We also tested the effectiveness of an Aurka inhibitor. RESULTS: We observed that genetic deletion of the Pten gene in the extrahepatic biliary epithelium and peri-ductal glands initiated sclerosing cholangitis-like lesions in mice, resulting in enlarged and distorted extrahepatic bile ducts in mice as early as 1 month after birth. Histologically, these lesions exhibited increased epithelial proliferation, inflammatory cell infiltration, and fibrosis. With aging, the lesions progressed from low-grade dysplasia to invasive carcinoma. Trp53 inactivation further accelerated disease progression, potentially by downregulating senescence. Further mechanistic studies showed that both human and mouse eCCA showed high expression of AURKA. Notably, the genetic deletion of Aurka completely eliminated Pten deficiency-induced extrahepatic bile duct lesions. Furthermore, pharmacological inhibition of Aurka alleviated disease progression. CONCLUSIONS: Pten deficiency in extrahepatic cholangiocytes and peribiliary glands led to a cholangitis-to-cholangiocarcinoma continuum that was dependent on Aurka. These findings offer new insights into preventive and therapeutic interventions for extrahepatic CCA. IMPACT AND IMPLICATIONS: The aberrant PTEN-PI3K-AKT signaling pathway is commonly observed in human extrahepatic cholangiocarcinoma (eCCA), a disease with a poor prognosis. In our study, we developed a mouse model mimicking cholangitis to eCCA progression by conditionally deleting the Pten gene via Pdx1-Cre in epithelial cells and peribiliary glands of the extrahepatic biliary duct. The conditional Pten deletion in these cells led to cholangitis, which gradually advanced to dysplasia, ultimately resulting in eCCA. The loss of Pten heightened Akt signaling, cell proliferation, inflammation, fibrosis, DNA damage, epigenetic signaling, epithelial-mesenchymal transition, cell dysplasia, and cellular senescence. Genetic deletion or pharmacological inhibition of Aurka successfully halted disease progression. This model will be valuable for testing novel therapies and unraveling the mechanisms of eCCA tumorigenesis.

Albumin promoter-driven FlpO expression induces efficient genetic recombination in mouse liver.

Tissue-specific gene manipulations are widely used in genetically engineered mouse models. A single recombinase system, such as the one using Alb-Cre, has been commonly used for liver-specific genetic manipulations. However, most diseases are complex, involving multiple genetic changes and various cell types. A dual recombinase system is required for conditionally modifying different genes sequentially in the same cell or inducing genetic changes in different cell types within the same organism. A FlpO cDNA was inserted between the last exon and 3'-UTR of the mouse albumin gene in a bacterial artificial chromosome (BAC-Alb-FlpO). The founders were crossed with various reporter mice to examine the efficiency of recombination. Liver cancer tumorigenesis was investigated by crossing the FlpO mice with FSF-KrasG12D mice and p53frt mice (KPF mice). BAC-Alb-FlpO mice exhibited highly efficient recombination capability in both hepatocytes and intrahepatic cholangiocytes. No recombination was observed in the duodenum and pancreatic cells. BAC-Alb-FlpO-mediated liver-specific expression of mutant KrasG12D and conditional deletion of p53 gene caused the development of liver cancer. Remarkably, liver cancer in these KPF mice manifested a distinctive mixed hepatocellular carcinoma and cholangiocarcinoma phenotype. A highly efficient and liver-specific BAC-Alb-FlpO mouse model was developed. In combination with other Cre lines, different genes can be manipulated sequentially in the same cell, or distinct genetic changes can be induced in different cell types of the same organism.NEW & NOTEWORTHY A liver-specific Alb-FlpO mouse line was generated. By coupling it with other existing CreERT or Cre lines, the dual recombinase approach can enable sequential gene modifications within the same cell or across various cell types in an organism for liver research through temporal and spatial gene manipulations.

Hf and Co Dual Single Atoms Co-Doped Carbon Catalyst Enhance the Oxygen Reduction Performance.

Single-atom metal-doped M-N-C (M═Fe, Co, Mn, or Ni) catalysts exhibit excellent catalytic activity toward oxygen reduction reactions (ORR). However, their performance still has a large gap considering the demand for their practical applications. This study reports a high-performance dual single-atom doped carbon catalyst (HfCo-N-C), which is prepared by pyrolyzing Co and Hf co-doped ZIF-8 . Co and Hf are atomically dispersed in the carbon framework and coordinated with N to form Co-N4 and Hf-N4 active moieties. The synergetic effect between Co-N4 and Hf-N4 significantly enhance the catalytic activity and durability of the catalyst. In an acidic medium, the ORR half-wave potential (E1/2) of the catalyst is up to 0.82 V , which is much higher than that of the Co-N-C catalyst without Hf co-doping (0.80 V). The kinetic current density of the catalyst is up to 2.49 A cm-2 at 0.85 V , which is 1.74 times that of the Co-N-C catalyst without Hf co-doping. Moreover, the catalyst exhibits excellent cathodic performance in single proton exchange membrane fuel cells and Zn-air batteries. Furthermore, Hf co-doping can effectively suppress the formation of H2O2, resulting in significantly improved stability and durability.

Melatonin alleviates di-butyl phthalate (DBP)-induced ferroptosis of mouse leydig cells via inhibiting Sp2/VDAC2 signals.

As one of the endocrine-disrupting chemicals (EDCs), dibutyl phthalate (DBP) has been extensively used in industry. DBP has been shown to cause damage to Leydig cells, yet its underlying mechanism remains elusive. In this study, we show that DBP induces ferroptosis of mouse Leydig cells via upregulating the expression of Sp2, a transcription factor. Also, Sp2 is identified to promote the transcription of Vdac2 gene by binding to its promoter and subsequently involved in DBP-induced ferroptosis of Leydig cells. In addition, DBP is proved to induce ferroptosis via inducing oxidative stress, while inhibition of oxidative stress by melatonin alleviates DBP-induced ferroptosis and upregulation of Sp2 and VDAC2. Taken together, our findings demonstrate that melatonin can alleviate DBP-induced ferroptosis of mouse Leydig cells via inhibiting oxidative stress-triggered Sp2/VDAC2 signals.

ARTS is essential for di-2-ethylhexyl phthalate (DEHP)-induced apoptosis of mouse Leydig cells.

As an extensively employed plasticizer in industrial applications, di-2-ethylhexyl phthalate (DEHP) can induce apoptosis of mouse Leydig cells, yet the precise mechanism remains elusive. In the current study, we identified that DEHP could specially induced apoptosis in the Leydig cells of the testis tissue, accompanied with the upregulation of apoptosis-related protein in the TGF-ß signaling pathway (ARTS) in the cells. Overexpression of ARTS significantly induced apoptosis of TM3 cells, while knockdown of ARTS inhibited apoptosis. Furthermore, DEHP-induced apoptosis of TM3 cells could be alleviated by knockdown of ARTS, which indicated that ARTS was involved in DEHP-induced apoptosis of mouse Leydig cells. Bioinformation assay predicts that there are four potential p53-responsive elements (p53-REs) located at - 6060, - 5726, - 5631 and - 5554 before the transcription start site of ARTS gene, implying that gene transcription of ARTS could be regulated by p53. Interestingly, DEHP was shown to specifically upregulate the expression of p53 in the Leydig cells of the testis tissue and TM3 cells. Consistently, p53 was proved to bind to the RE4 site of the ARTS gene promoter and transcriptionally activated the promoter-driven expression of the luciferase reporter gene. Overexpression of p53 could induce apoptosis of TM3 cells; while knockdown of p53 could not only rescue DEHP-induced apoptosis of the cells, but also inhibit DEHP-caused upregulation of ARTS. Meanwhile, we showed that oxidative stress could induce apoptosis of TM3 cells, accompanied with the increased protein levels of p53 and ARTS; while inhibition of oxidative stress dramatically alleviated DEHP-induced apoptosis and the up-regulation of p53 and ARTS. Taken together, these results indicated that DEHP-induced oxidative stress activates the p53-ARTS cascade to promote apoptosis of mouse Leydig cells.

Ultrathin Co-N-C Layer Modified Pt-Co Intermetallic Nanoparticles Leading to a High-Performance Electrocatalyst toward Oxygen Reduction and Methanol Oxidation.

The development of low platinum-based alloy electrocatalysts is crucial to accelerate the commercialization of fuel cells, yet remains a synthetic challenge and an incompatibility between activity and stability. Herein, a facile procedure to fabricate a high-performance composite that comprises Pt-Co intermetallic nanoparticles (IMNs) and Co, N co-doped carbon (Co-N-C) electrocatalyst is proposed. It is prepared by direct annealing of homemade carbon black-supported Pt nanoparticles (Pt/KB) covered with a Co-phenanthroline complex. During this process, most of Co atoms in the complex are alloyed with Pt to form ordered Pt-Co IMNs, while some Co atoms are atomically dispersed and doped in the framework of superthin carbon layer derived from phenanthroline, which is coordinated with N to form Co-Nx moieties. Moreover, the Co-N-C film obtained from complex is observed to cover the surface of Pt-Co IMNs, which prevent the dissolution and agglomeration of nanoparticles. The composite catalyst exhibits high activity and stability toward oxygen reduction reactions (ORR) and methanol oxidation reactions (MOR), delivering outstanding mass activities of 1.96 and 2.92 A mgPt -1 for ORR and MOR respectively, owing to the synergistic effect of Pt-Co IMNs and Co-N-C film. This study may provide a promising strategy to improve the electrocatalytic performance of Pt-based catalysts.

A mouse model for high-efficient Flp-recombinase-mediated genetic manipulation in the pancreas.

BACKGROUND: Tissue and cell-specific gene targeting has been widely employed in biomedical research. In the pancreas, the commonly used Cre recombinase recognizes and recombines loxP sites. However, to selectively target different genes in distinct cells, a dual recombinase system is required. METHOD: We developed an alternative recombination system mediated by FLPo, which recognizes frt DNA sequences for pancreatic dual recombinase-mediated genetic manipulation. An IRES-FLPo cassette was targeted between the translation stop code and 3-UTR of the mouse pdx1 gene in a Bacterial Artificial Chromosome using recombineering technology. Transgenic BAC-Pdx1-FLPo mice were developed by pronuclear injection. RESULTS: Highly efficient recombination activity was observed in the pancreas by crossing the founder mice with Flp reporter mice. When the BAC-Pdx1-FLPo mice were bred with conditional FSF-KRasG12D and p53 F/F mice, pancreatic cancer developed in the compound mice. The characteristics of pancreatic cancer resembled those derived from conditional LSL-KRasG12D and p53 L/L mice controlled by pdx1-Cre. CONCLUSIONS: We have generated a new transgenic mouse line expressing FLPo, which enables highly efficient pancreatic-specific gene recombination. When combined with other available Cre lines, this system can be utilized to target different genes in distinct cells for pancreatic research.

DDIT4 is essential for DINP-induced autophagy of ovarian granulosa cells.

As one of the most important phthalates, di-isononyl phthalate (DINP) has been widely used as a common plasticizer in the food and personal care products sectors. In our previous study, we found that DINP can induce autophagy of ovarian granulosa cells; while the underlying mechanism is unclear. In the study, we showed that DINP exposure could induce autophagy of ovarian granulosa cells and KGN cells, accompanied with the increase in the mRNA and protein level of DDIT4. Furthermore, overexpression of DDIT4 were shown to induce autophagy of KGN cells; while knockdown of DDIT4 inhibited DINP-induced autophagy, implying that DDIT4 played an important role in DINP-induced autophagy of ovarian granulosa cells. There were three putative binding sites of transcription factor ATF4 in the promoter region of DDIT4 gene, suggesting that DDIT4 might be regulated by ATF4. Herein, we found that overexpression of ATF4 could upregulate the expression of DDIT4 in KGN cells, while knockdown of ATF4 inhibited its expression. Subsequently, ATF4 was identified to bind to the promoter region of DDIT4 gene and promote its transcription. The expression of ATF4 was also increased in the DINP-exposed granulosa cells, and ATF4 overexpression promoted autophagy of KGN cells; whereas knockdown of ATF4 alleviated DINP-induced upregulation of DDIT4 and autophagy of the cells. Taken together, DINP triggered autophagy of ovarian granulosa cells through activating ATF4/DDIT4 signals.

Bisphenol A (BPA) induces apoptosis of mouse Leydig cells via oxidative stress.

As one of the most frequently produced synthetic compounds worldwide, bisphenol A (BPA) has been widely used in many kinds of products such as appliances, housewares, and beverage cans. BPA has been shown to cause damage to male reproductive system; however, the potential mechanism remains to be investigated. In the present study, BPA exposure decreased the testis and epididymis coefficient, caused a disintegration of germinal epithelium, decreased the density and motility of sperm in the epididymis tissue, and increased the number of abnormal sperm morphology, which indicated that BPA exposure could cause damage to testis. BPA was also shown to induce apoptosis and oxidative stress in the testis tissue. The serum testosterone concentration was decreased in the BPA-treated group, suggesting that BPA could lead to Leydig cell damage. Subsequently, mouse TM3 cell, a kind of mouse Leydig cell line, was utilized to investigate the potential mechanism. Herein, we showed that BPA exposure could inhibit cell viability and induce apoptosis of TM3 cells. Furthermore, oxidative stress in the cells could also be induced by BPA, while the inhibition of oxidative stress by N-acetyl-L-cysteine (NAC), an oxidative stress scavenger, could reverse the inhibition of cell viability and induction of apoptosis by BPA exposure, indicating that oxidative stress was involved in BPA-induced apoptosis of TM3 cells. Finally, RNA-sequencing and real-time PCR were utilized to screen and validate the potential oxidative stress-related genes involving in BPA-induced apoptosis. We found that BPA exposure increased the mRNA levels of oxidative stress-related genes such as Lonp1, Klf4, Rack1, Egln1, Txn2, Msrb1, Atox1, Mtr, and Atp2a2, as well as decreased the mRNA level of Dhfr gene; while NAC could rescue the expression of these genes. Taken together, oxidative stress was involved in BPA-induced apoptosis of mouse Leydig cells.

High-speed Ge-on-GaAs photodetector.

In this work, a germanium (Ge) on gallium arsenide (GaAs) photodetector is demonstrated with the optical response from 850 nm to 1600 nm, which has potential for monolithic integration with VCSELs on GaAs platform as transceiver working beyond 900 nm. The device exhibits a responsivity of 0.35A/W, 0.39 A/W and 0.11 A/W at 1000 nm, 1310 nm and 1550 nm, respectively and dark current of 8 nA at -1 V. The 10 µm diameter back-illuminated device achieves a 3-dB bandwidth of 9.3 GHz under -2 V bias. A donor-like trap at the interface between the Ge and GaAs collection layers is verified by capacitance-voltage curve and deep-level transient spectroscopy (DLTS) measurement, which impedes the depletion in GaAs collection layers.

Di-isononyl phthalate induces apoptosis and autophagy of mouse ovarian granulosa cells via oxidative stress.

Di-isononyl phthalate (DINP) has been widely utilized in industrial, commercial and medical applications for the past few years. Therefore, more attention should be paid to the toxicity of DINP. DINP can cause damage to female reproductive system; however, the potential mechanism remains to be further investigated. In this study, female mice were orally administered with 0, 2, 20 and 200 mg DINP/kg/day for 14 days. We found that DINP significantly affected the arrangement of granulosa cells in ovarian follicles. In addition, DINP could induce apoptosis, autophagy and oxidative stress of the ovary tissue. Meanwhile, the serum estradiol concentration distinctly decreased in the 20 and 200 mg/kg DINP-treated groups, suggesting that DINP might affect the function of ovarian granulosa cells. Primary mouse ovarian granulosa cells were utilized for further investigation after the cells were treated with 0, 100, 200, 400 µM DINP for 24 h. Similar to the in vivo experiment, DINP could also induce apoptosis and autophagy of ovarian granulosa cells, as well as oxidative stress; while inhibition of oxidative stress by NAC could alleviate DINP-induced apoptosis and autophagy. Furthermore, inhibition of autophagy by 3-MA could also rescue the induction of apoptosis by DINP. Taken together, these results indicated that DINP induced apoptosis and autophagy of mouse ovarian granulosa cells via oxidative stress, and autophagy played a cytotoxic role in DINP-induced apoptosis.

Role of autophagy in lysophosphatidylcholine-induced apoptosis in mouse Leydig cells.

Lysophosphatidylcholine (LPC), a major class of glycerophospholipids ubiquitously present in most tissues, plays a dominant role in many diseases, while it is still unknown about the potential mechanism of LPC affecting the testicular Leydig cells. In the present study, mouse TM3 Leydig cells in vitro were treated with LPC for 48 h. LPC was found to significantly induce apoptosis and oxidative stress of mouse TM3 Leydig cells; while inhibition of oxidative stress by N-acetyl-L-cysteine, an inhibitor of oxidative stress, could rescue the induction of apoptosis, indicating that LPC induced apoptosis of mouse TM3 Leydig cells via oxidative stress. Interestingly, LPC was showed to inhibit autophagy; however, induction of autophagy by rapamycin significantly alleviated the induction of apoptosis by LPC. Taken together, oxidative stress was involved in LPC-induced apoptosis of mouse TM3 Leydig cells, and autophagy might play a protective role in LPC-induced apoptosis.

Role of Autophagy in Lysophosphatidylcholine-Induced Apoptosis of Mouse Ovarian Granulosa Cells.

Lysophosphatidylcholine (LPC), also known as lysolecithin, is one of the major components of oxidized low-density lipoproteins (ox-LDL). In the pathogenetic process of diverse diseases, LPC acts as a significant lipid mediator. However, no evidence shows that LPC can affect the female reproductive system. In our study, we found that LPC inhibited the cell viability of primary mouse ovarian granulosa cells. Meanwhile, LPC was shown to induce apoptosis, which is accompanied by an increase in apoptosis-related protein levels, such as cleaved caspase-3, cleaved caspase-8 and Bax, as well as a decrease in Bcl-2. The total numbers of early and late apoptotic cells also increased in the LPC-treated cells. These results indicated that LPC could induce apoptosis of mouse ovarian granulosa cells. Furthermore, the increase in autophagy-related protein levels and the number of autophagic vesicles suggested that LPC could induce autophagy. The inhibition of oxidative stress by N-acetyl-L-cysteine (NAC) could rescue the induction of apoptosis and autophagy by LPC, which indicated that oxidative stress was involved in LPC-induced apoptosis and autophagy. Interestingly, the inhibition of autophagy by 3-MA could reserve the inhibition of cell viability and the induction of apoptosis by LPC. In conclusion, oxidative stress was involved in LPC-induced apoptosis, whileautophagy of mouse ovarian granulosa cells and the inhibition of autophagy could alleviate LPC-induced apoptosis.

Spectral caustics of high-order harmonics in one-dimensional periodic crystals.

We theoretically investigate the spectral caustics of high-order harmonics in solids. We analyze the one-dimensional model of high-order harmonic generation (HHG) in solids and find that apart from the caustics originating from the van Hove singularities in the energy band structure, another kind of catastrophe enhancement also emerges in solids when the different branches of electron-hole trajectories generating high-order harmonics coalesce into a single branch. We solve the time-dependent Schrödinger equation in terms of the periodic potential and demonstrate the control of this kind of singularity in HHG with the aid of two-color laser fields. The diffraction patterns of the harmonic spectrum near the caustics agree well with the interband electron-hole recombination trajectories predicted by the semiconductor semiclassical equation. This work is expected to improve our understanding of the HHG dynamics in solids and enable us to manipulate the harmonic spectrum by adjusting the driving field parameters.

The active fragments of ghrelin cross the blood-brain barrier and enter the brain to produce antinociceptive effects after systemic administration.

G (1-5)-NH2, G (1-7)-NH2, and G (1-9) are the active fragments of ghrelin. The aim of this study was to investigate the antinociceptive effects, their ability to cross the blood-brain barrier, and the receptor mechanism(s) of these fragments using the tail withdrawal test in male Kunming mice. The antinociceptive effects of these fragments (2, 6, 20, and 60 nmol/mouse) were tested at 5, 10, 20, 30, 40, 50, and 60 min after intravenous (i.v.) injection. These fragments induced dose- and time-related antinociceptive effects relative to saline. Using the near infrared fluorescence imaging experiments, our results showed that these fragments could cross the brain-blood barrier and enter the brain. The antinociceptive effects of these fragments were completely antagonized by naloxone (intracerebroventricular, i.c.v.); however, naloxone methiodide (intraperitoneal, i.p.), which is the peripheral restricted opioid receptor antagonist, did not antagonize these antinociceptive effects. Furthermore, the GHS-R1α antagonist [D-Lys3]-GHRP-6 (i.c.v.) completely antagonized these antinociceptive effects, too. These results suggested that these fragments induced antinociceptive effects through central opioid receptors and GHS-R1α. In conclusion, our studies indicated that these active fragments of ghrelin could cross the brain-blood barrier and enter the brain and induce antinociceptive effects through central opioid receptors and GHS-R1α after intravenous injection.

The role of protein kinase C alpha in tri-ortho-cresyl phosphate-induced autophagy in human neuroblastoma SK-N-SH cells.

As an organophosphorus ester, tri-ortho-cresyl phosphate (TOCP) has been widely used in agriculture and industry. It is reported that TOCP can induce organophosphate-induced delayed neuropathy (OPIDN) in sensitive animal and human species. However, the exact molecular mechanisms underlying TOCP-induced neurotoxicity are still unknown. In this study, we found that TOCP could induce autophagy by activating protein kinase C alpha (PKCα) signaling in neuroblastoma SK-N-SH cells. PKCα activators could positively regulate TOCP-induced autophagy by increasing the expression levels of neighbor BRCA1 gene protein 1 (NBR1), LC3 and P62 autophagic receptor protein. Furthermore, PKCα activation impaired the ubiquitin-proteasome system (UPS), resulting in inhibition of proteasome activity and accumulation of ubiquitinated proteins. UPS dysfunction could stimulate autophagy to serve as a compensatory pathway, which contributed to the accumulation of the abnormally hyperphosphorylated tau proteins and degradation of impaired proteins of the MAP 2 and NF-H families in neurodegenerative disorders.

Involvement of oxidative stress in ZnO NPs-induced apoptosis and autophagy of mouse GC-1 spg cells.

Zinc oxide nanoparticles (ZnO NPs) have been extensively used in various industries and reported to inhibit spermatogenesis, however, ZnO NPs-induced spermatogenesis failure is yet to be fully elucidated. Herein, mouse-derived spermatogonia cell line GC-1 spg cells were treated with ZnO NPs for 24 h in the presence or absence of radical scavenger N-acetyl-L-cysteine (NAC) or autophagy inhibitor 3-methyladenine (3-MA), then cell viability was observed by MTT assay; apoptosis was observed by western blotting analysis and AnnexinV-FITC/PI assay, respectively; autophagy was detected by western blotting analysis and transmission electron microscopy, respectively; and the contents of MDA and GSH and the activities of SOD and GSH-PX were measured by oxidative stress kits. The present study showed that ZnO NPs exposure inhibited viability and induced apoptosis of mouse GC-1 spg cells. Intriguingly, ZnO NPs markedly increased the protein content of LC3-II, the ratio of LC3-II/LC3-I, and the protein levels of ATG 5 and Beclin 1 in the cells. Furthermore, transmission electron microscopy (TEM) showed that autophagic vesicles in the cytoplasm increased significantly in the ZnO NPs-treated cells, indicating that ZnO NPs could induce autophagy of the cells. Oxidative stress could be induced by ZnO NPs; moreover, inhibition of oxidative stress could alleviate the induction of apoptosis and autophagy by ZnO NPs. Inhibition of autophagy by 3-MA could rescue the inhibition of cell viability and induction of apoptosis by ZnO NPs, which indicated that autophagy might have cytotoxic effect on ZnO NPs-induced apoptosis. In summary, oxidative stress was involved in ZnO NPs-induced apoptosis and autophagy of mouse GC-1 spg cells, and autophagy might play a cytotoxic role in ZnO NPs-induced apoptosis.

Di-2-ethylhexyl phthalate (DEHP) induces apoptosis and autophagy of mouse GC-1 spg cells.

As a widely used plasticizer in industry, di-2-ethylhexylphthalate (DEHP) can cause testicular toxicity, yet little is known about the potential mechanism. In this study, DEHP exposure dramatically inhibited cellviability and induced apoptosis of mouse GC-1 spg cells. Furthermore, DEHP significantly increased the levels of autophagy proteins LC3-II, Beclin1 and Atg5, as well as the ratio ofLC3-II/LC3-I. Transmission electron microscopy (TEM) further confirmed that DEHP induced autophagy of mouse GC-1 spg cells. DEHP was also shown to induceoxidative stress; while inhibition of oxidative stress with NAC could increase cell viability and inhibit DEHP-induced apoptosis and autophagy. These results suggested that DEHP induced apoptosis and autophagy of mouse GC-1 spg cells via oxidative stress. 3-MA, an inhibitor of autophagy, could rescue DEHP-induced apoptosis. In summary, DEHP induced apoptosis and autophagy of mouse GC-1 spg cells via oxidative stress, and autophagy might exert a cytotoxic effect on DEHP-induced apoptosis.

Tea polyphenols alleviate tri-ortho-cresyl phosphate-induced autophagy of mouse ovarian granulosa cells.

Tri-ortho-cresyl phosphate (TOCP), a widely used plasticizer in industry, can cause female reproductive damage. Tea polyphenols (TPs) have multiple health effects via inhibiting oxidative stress. However, the reproductive protection of TPs in TOCP-induced female reproductive system damage is yet to be elucidated. In the study, TOCP inhibited cell viability and induced autophagy of mouse ovarian granulosa cells; while TPs could rescue the inhibition of viability and induction of autophagy. 3-MA, an autophagy inhibitor, could also rescue the inhibition of cell viability. These results indicated that TPs played a protective role in TOCP-induced autophagy. Furthermore, TPs could inhibit the induction of oxidative stress of the cells by TOCP, which implying that TPs might alleviate TOCP-induced autophagy via inhibiting oxidative stress. Furthermore, TPs could rescue TOCP-induced autophagy and oxidative stress in the mouse ovarian tissues. Taken together, these results indicated that TPs could protect TOCP-induced ovarian damage via inhibiting oxidative stress.

Transgenic expression of cyclooxygenase-2 in pancreatic acinar cells induces chronic pancreatitis.

Replacement of the exocrine parenchyma by fibrous tissue is a main characteristic of chronic pancreatitis. Understanding the mechanisms of pancreatic fibrogenesis is critical for the development of preventive and therapeutic interventions. Cyclooxygenase-2 (COX-2), a rate-limiting enzyme for prostaglandin synthesis, is expressed in patients with chronic pancreatitis. However, it is unknown whether COX-2 can cause chronic pancreatitis. To investigate the roles of pancreatic acinar COX-2 in fibrogenesis and the development of chronic pancreatitis, COX-2 was ectopically expressed specifically in pancreatic acinar cells in transgenic mice. Histopathological changes and expression levels of several profibrogenic factors related to chronic pancreatitis were evaluated. COX-2 was expressed in the pancreas of the transgenic mice, as detected by Western blot analysis. Immunohistochemical staining showed COX-2 was specifically expressed in pancreatic acinar cells. COX-2 expression led to progressive changes in the pancreas, including pancreas megaly, persistent inflammation, collagen deposition, and acinar-to-ductal metaplasia. Quantitative RT-PCR and immunostaining showed that profibrogenic factors were upregulated and pancreatic stellate cells were activated in the COX-2 transgenic mice. Expression of COX-2 in pancreatic acinar cells is sufficient to induce chronic pancreatitis. Targeting this pathway may be valuable in the prevention of chronic pancreatitis. NEW & NOTEWORTHY COX-2 expression is observed in pancreatic tissues of human chronic pancreatitis. In this study, we showed that COX-2 expression caused the development of chronic pancreatitis in transgenic mice, supporting the idea that COX-2 inhibition may be an effective preventive and therapeutic strategy.