Role of calcium-sensing receptor in regulating activation susceptibility of postovulatory aging mouse oocytes.

The mechanisms underlying postovulatory oocyte aging (POA) remain largely unknown. The expression of the calcium-sensing receptor (CaSR) in mouse oocytes and its role in POA need to be explored. Our objective was to observe CaSR expression and its role in the susceptibility to activating stimuli (STAS) in POA mouse oocytes. The results showed that, although none of the newly ovulated oocytes were activated, 40% and 94% of the oocytes recovered 19 and 25 h after human chorionic gonadotropin (hCG) injection were activated, respectively, after ethanol treatment. The level of the CaSR functional dimer protein in oocytes increased significantly from 13 to 25 h post hCG. Thus, the CaSR functional dimer level was positively correlated with the STAS of POA oocytes. Aging in vitro with a CaSR antagonist suppressed the elevation of STAS, and cytoplasmic calcium in oocytes recovered 19 h post hCG, whereas aging with a CaSR agonist increased STAS, and cytoplasmic calcium of oocytes recovered 13 h post hCG. Furthermore, the CaSR was more important than the Na-Ca2+ exchanger in regulating oocyte STAS, and T- and L-type calcium channels were inactive in aging oocytes. We conclude that the CaSR is involved in regulating STAS in POA mouse oocytes, and that it is more important than the other calcium channels tested in this connection.

Role of calcium-sensing receptor in regulating spontaneous activation of postovulatory aging rat oocytes.

Mechanisms for postovulatory aging (POA) of oocytes and for spontaneous activation (SA) of rat oocytes are largely unknown. Expression of calcium-sensing receptor (CaSR) in rat oocytes and its role in POA remain unexplored. In this study, expression of CaSR in rat oocytes aging for different times was detected by immunofluorescence microscopy, and western blotting and the role of CaSR in POA was determined by observing the effects of regulating its activity on SA susceptibility and cytoplasmic calcium levels. The results showed that CaSR was expressed in rat oocytes. Oocytes recovered 19 h post human chorionic gonadotropin (hCG) injection were more susceptible to SA and expressed more functional CaSR than oocytes recovered 13 h after hCG injection, although both expressed the same level of total CaSR protein. Treatment with CaSR antagonist significantly suppressed cytoplasmic calcium elevation and SA of oocytes. Activation of Na-Ca2+ exchanger with NaCl inhibited SA to a greater extent than suppression of CaSR with NPS-2143, suggesting that calcium sources other than CaSR-controlled channels contributed to the elevation of cytoplasmic calcium. Treatment with T- or L-type calcium channel blockers significantly reduced SA. Suppression of all calcium channels tested reduced SA to minimum. It is concluded that the level of CaSR functional dimer protein, but not that of the total CaSR protein, was positively correlated with the SA susceptibility during POA of rat oocytes confirming that CaSR is involved in POA regulation. Blocking multiple calcium channels might be a better choice for efficient control of SA in rat oocytes.

Corticotrophin-releasing hormone and corticosterone impair development of preimplantation embryos by inducing oviductal cell apoptosis via activating the Fas system: an in vitro study.

STUDY QUESTION: What are the mechanisms by which corticotrophin-releasing hormone (CRH) and corticosterone impair the development of preimplantation embryos in the oviduct. SUMMARY ANSWER: CRH and corticosterone do not affect preimplantation embryos directly, but impair their development indirectly by triggering apoptosis of oviductal epithelial cells (OECs) through activation of the Fas system. WHAT IS KNOWN ALREADY: Studies report that stress impairs embryo development with facilitated secretion of CRH and glucocorticoids. Although an in vivo study demonstrated that preimplantation stress impaired embryo development in conjunction with oviductal apoptosis and activation of the Fas system, whether CRH or glucocorticoids damage embryos directly or indirectly by way of oviductal cells remains to be clarified. STUDY DESIGN, SIZE, DURATION: Mice of Kunming strain, the generalized lymphoproliferative disorder (gld) mice with a germline mutation F273L in Fas ligand in a C57BL/6J genomic background and the wild-type C57BL/6J mice were used. Female mice were used 8-10 weeks after birth. PARTICIPANTS/MATERIALS, SETTING, METHODS: While some female mice were killed 48 h after being injected with equine CG to collect oviducts and prepare OECs, others were killed to recover zygotes after mating with males following superovulation with eCG and hCG. The zygotes obtained were cultured with or without CRH or corticosterone (CRH/Cort) either in Chatot-Ziomek-Bavister (CZB) medium with or without OECs or in conditioned medium (CM) conditioned with OECs pretreated or not with CRH/Cort. Preimplantation development, levels of redox potential and apoptosis, and expression of CRH receptor 1 (CRHR1), glucocorticoid receptor (GR), Fas and 11ß-hydroxysteroid dehydrogenase (HSD) were observed in embryos recovered at different times of in vitro culture. After culture of OECs with or without CRH/Cort, levels of redox potential and apoptosis, mRNA and protein expression of growth factors, and protein expression of CRHR1, GR and Fas were examined in OECs and the level of FasL was measured in CM. The gld mice were used to confirm a role for the Fas system in triggering apoptosis of embryos and oviducts. MAIN RESULTS AND THE ROLE OF CHANCE: This study showed that blastocyst development was unaffected when mouse zygotes were cultured in CZB medium containing various concentrations of CRH/Cort but was impaired when embryos were cultured with CRH/Cort plus OECs or in CM conditioned with OECs pretreated with CRH/Cort (treatment CM). Culture in treatment-CM induced oxidative stress and apoptosis in embryos. Preimplantation embryos expressed GR and Fas at all stages and CRHR1 at the blastocyst stage only. Mouse 4-cell embryos and blastocysts expressed HSD2 but not HSD1. Culture of OECs with CRH/Cort increased their oxidative stress, apoptosis, CRHR1, Fas and FasL while decreasing their GR and growth factors. Blastocyst development in treatment-CM conditioned with OECs from gld mice harboring FasL mutations was superior to treatment-CM conditioned with wild-type mouse OECs. The results suggest that CRH/Cort impairs embryo development indirectly by inducing oviductal apoptosis via activating the Fas system. The insensitivity of preimplantation embryos to CRH and corticosterone is due to, respectively, a lack of CRHR and the exclusive expression of HSD2 that inactivate corticosterone. LARGE SCALE DATA: Not applicable. LIMITATIONS, REASONS FOR CAUTION: Although significant, the conclusions were drawn from limited results obtained using mice and thus they need further verification in other species. For example, bovine embryos express both HSD1 and HSD2 at all the preimplantation stages whereas mouse preimplantation embryos express HSD2 exclusively without HSD1. WIDER IMPLICATIONS OF THE FINDINGS: The data are important for our understanding of the mechanisms by which stress affects female reproduction in both human and animals, as early stages of pregnancy are considered more vulnerable to stress than the late stages. STUDY FUNDING AND COMPETING INTEREST(S): This study was supported by grants from the National Basic Research Program of China (Nos. 2014CB138503 and 2012CB944403), the China National Natural Science Foundation (Nos. 31272444 and 30972096) and the Animal breeding improvement program of Shandong Province. All authors declare that their participation in the study did not involve factual or potential conflicts of interests.

Preimplantation maternal stress impairs embryo development by inducing oviductal apoptosis with activation of the Fas system.

STUDY QUESTION: What are the mechanisms by which the preimplantation restraint stress (PIRS) impairs embryo development and pregnancy outcome? SUMMARY ANSWER: PIRS impairs embryo development by triggering apoptosis in mouse oviducts and embryos,and this involves activation of the Fas system. WHAT IS KNOWN ALREADY: Although it is known that the early stages of pregnancy are more vulnerable than later stages to prenatalstress, studies on the effect of preimplantation stress on embryo developmentare limited. Furthermore, the mechanisms by which psychological stress impairs embryo development are largely unknown. These issues are worth exploring using the mouse PIRS models because restraint of mice is an efficient experimental procedure developed for studies of psychogenic stress. STUDY DESIGN, SIZE AND DURATION: Mice of Kunming strain, the generalized lymphoproliferative disorder (gld) mice with a germline mutation F273L in FasL in a C57BL/6J genomic background and the wild-type C57BL/6J mice were used. Female and male mice were used 8-10 weeks and 10-12 weeks after birth, respectively. Female mice showing vaginal plugs were paired by weight and randomly assigned to restraint treatments or as controls. For restraint treatment, an individual mouse was put in a micro-cage with food and water available. Control mice remained in their cages with food and water during the time treated females were stressed. PARTICIPANTS/MATERIALS, SETTING, METHODS: Female mice were exposed to PIRS for 48 h starting from 16:00 on the day of vaginal plug detection. At the end of PIRS, levels of glucorticoids (GC), corticotropin-releasing hormone (CRH)and redox potential were measured in serum, while levels of GC, GC receptor (GR), CRH, CRH receptor (CRHR), Fas and Fas ligand (FasL) protein, mRNAs for brain derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1), oxidative stress (OS) and apoptosis were examined in oviducts. Preimplantation development and levels of GR, Fas, redox potential and apoptosis were observed in embryos recovered at different times after the initiation of PIRS. The gld mice were used to confirm a role for the Fas system in triggering apoptosis of embryos and oviducts. MAIN RESULTS AND THE ROLE OF CHANCE: Compared to those in control mice, while the number of blastocysts/mouse (5.0 ± 0.7 versus 11.1 ± 0.5), cell number/blastocyst (49.1 ± 1.3 versus 61.5 ± 0.9), percentages of term pregnancy (37.5% versus 90.9%) and litter size (3.7 ± 0.1versus 9.6 ± 0.6) decreased, blood CRH (560 ± 23 versus 455 ± 37 pg/ml), cortisol (27.3 ± 3.4 versus 5 ± 0.5 ng/ml) and OS index (OSI: 2.8 versus 1.7) increased significantly (all P < 0.05) following PIRS. In the oviduct, while levels of CRH (1175 ± 85 versus 881 ± 33 pg/100 mg), cortisol (28.9 ± 1.7 versus14 ± 4 ng/g), CRHR (2.3 ± 0.3 versus 1.0 ± 0.0), FasL (1.31 ± 0.06 versus 1.08 ± 0.05 ng/g), Fas (1.42 ± 0.13 versus 1.0 ± 0.0) and apoptotic cells (19.1 ± 0.5% versus 8.4 ± 0.4%) increased, levels of GR proteins (0.67 ± 0.14 versus 1.0 ± 0.0) and Igf-1 (0.6 ± 0.09 versus 1.0 ± 0.0) and Bdnf (0.73 ± 0.03 versus 1.0 ± 0.0) mRNAs decreased significantly (all P < 0.05 versus control) after PIRS. Mouse embryos expressed GR and Fas at all stages of preimplantation development and embryo OS (GSH/GSSG ratio: 0.88 ± 0.03 versus 1.19 ± 0.13) and annexin-positive cells (blastocysts: 31.4 ± 3.8% versus 10.96 ± 3.4%) increased significantly (P < 0.05) following PIRS. Furthermore, the detrimental effects of PIRS on embryo development and oviductal apoptosis were much reduced in gld mice. Thus, PIRS triggered apoptosis in oviductal cells with activation of the Fas/FasL system. The apoptotic oviductal cells promoted embryo apoptosis with reduced production of IGF-1 and BDNF and increased production of FasL. LIMITATIONS, REASONS FOR CAUTION: Although important, the conclusions were drawn from limited results obtained using a single model in one species and thus they need further verification using other models and/or in other species. Furthermore, as differences in stressed samples were modest and sometimes not significant between gld and wild-type mice whereas differences between control and stressed samples were always present within gld mice, it is deduced that signaling pathways other than the Fas/FasL system might be involved as well in the PIRS-triggered apoptosis of oviducts and embryos. WIDER IMPLICATIONS OF THE FINDINGS: The data are important for studies on the mechanisms by which psychological stress affects female reproduction, as FasL expression has been observed in human oviduct epithelium. LARGE SCALE DATA: Not applicable. STUDY FUNDING AND COMPETING INTERESTS: This study was supported by grants from the National Basic Research Program of China (Nos. 2014CB138503 and 2012CB944403), the China National Natural Science Foundation (Nos. 31272444 and 30972096) and the Animal breeding improvement program of Shandong Province. All authors declare that their participation in the study did not involve factual or potential conflicts of interests.

Screening and cloning gene of a hepatocyte protein interacting with HCV NS5ATP4A protein / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To screen and clone hepatocyte protein interacting with hepatitis C virus NS5ATP4A protein for studying its biological functions.</p><p><b>METHODS</b>Bait plasmids of hepatitis C virus NS5ATP4A were constructed. After verifying that hepatitis C virus NS5ATP4A protein could be steadily expressed in AH109 yeast strain, yeast-two hybrid assay was performed by mating AH109 with Y187 which pre-transformed with liver cDNA library plasmids pACT2, and the diploidy yeast cells were plated on quadruple dropout (QDO) medium and assayed for X-a-gal activity. Nineteen yeast colonies which grew on QDO and had a-gal activity were obtained, and then the library plasmids were extracted and sequenced.</p><p><b>RESULTS</b>Seven genes were screened out and one of them was a formerly unknown gene. They were associated with RNA synthesis, protein translation, cell cycling and tumor immunity.</p><p><b>CONCLUSION</b>NS5ATP4A binding proteins were successfully screened, which offers new clues for further studying the signal transduction pathway of NS5ATP4A and the pathogenic mechanism of HCV.</p>

Construction and identification of matrix metalloproteinase inhibitor-1 siRNA eukaryotic expression vectors / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To construct TIMP-1 siRNA eukaryotic expression vectors and evaluate their effect on TIMP-1 mRNA expression in hepatic stellate cells.</p><p><b>METHODS</b>The combinant lone DNA with cutting sites of BamH I and Xho I enzyme according to the sequences of 447-465, 552-540 TIMP-1 of rats and nonspecific sequence were selected and cloned to pGEM-T vector and sub-cloned to pRNAT-U6.2. They were then identified by double enzyme digestion analysis and DNA sequencing. Three plasmids were transfected into T6 separately through an oligofectamine package. TIMP-1 mRNA expression was evaluated by RT-PCR.</p><p><b>RESULTS</b>Targeting sequences of TIMP-1 siRNA eukaryotic expression vectors were correct. TIMP-1 mRNA expression was significantly reduced by transfecting them into the T6.</p><p><b>CONCLUSION</b>We successfully constructed two TIMP-1 siRNA eukaryotic expression vectors and the transfected cells can significantly suppress the TIMP-1 expression.</p>

Study of huchang qingfei pellets on immune function in rats infected with Mycoplasma pneumoniae / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effects and mechanism of Huchang Qingfei pellets on immune function in rats infected with mycoplasma pneumoniae.</p><p><b>METHOD</b>A rat model of mycoplasmal pneumonia (MP) was developed in repeated intranasal infectious routes and then the humoral and cellular immunocompetences were detected by radioimmunoassay, immune-turbidimetry and flow cytometry.</p><p><b>RESULT</b>The levels of serum IgG,IgM and IL-2, IL-6 were enhinced obviously, the complement C3 and TNF-alpha were decreased and the ratio of CD4+ /CD8+ was improved significantly in the Huchang groups as compared with MP model group.</p><p><b>CONCLUSION</b>Huchang Qingfei pellets can reinforce immune function via preventing both cellular and humoral immunity from depression in the rats with MP.</p>

Effect of Huchang Qingfei concentrated pellets on E-cadherin expression in lung tissue of mice infected with Mycoplasma pneumoniae / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effects of Huchang Qingfei concentrated pellets on the expression of E-cadherin (E-cd) in the lung tissue from mice infected with Mycoplasma pneumoniae (MP).</p><p><b>METHOD</b>A mice model of Mycoplasmal pneumonia (MPP) was developed by repeatedly intranasal infectious route. Transmission electronic microscope (TEM) and immunohistochemistry stain were performed to observe the pathological changes and expression of E-cd in lung tissues.</p><p><b>RESULT</b>Under TEM it was found that the cellular membrane was ruptured, mitochondria was denatured, crista was broken in the pulmonary cells of the model group; the all above parameters in Huchang medicated group were improved obviously. The immunohistochemistry test showed that strong positive brown stain of E-cd expression was found in the pulmonary epithelial cell membrane and bronchial periphery in the model group, however, in the medicated group, the E-cd expression level in the cellular membrane was decreased and the expression ratio was dropped significantly as compared with the model controls.</p><p><b>CONCLUSION</b>Huchang Qingfei concentrated pellets can inhibit the overexpression of E-cd in the lung tissue of mice with MP-infection, which may be helpful for prevention and treatment of pulmonary injury caused by MPP.</p>