The role of tyrosine phosphatase Shp2 in spermatogonial differentiation and spermatocyte meiosis / 亚洲男科学杂志(英文版)

The transition from spermatogonia to spermatocytes and the initiation of meiosis are key steps in spermatogenesis and are precisely regulated by a plethora of proteins. However, the underlying molecular mechanism remains largely unknown. Here, we report that Src homology domain tyrosine phosphatase 2 (Shp2; encoded by the protein tyrosine phosphatase, nonreceptor type 11 [Ptpn11] gene) is abundant in spermatogonia but markedly decreases in meiotic spermatocytes. Conditional knockout of Shp2 in spermatogonia in mice using stimulated by retinoic acid gene 8 (Stra8)-cre enhanced spermatogonial differentiation and disturbed the meiotic process. Depletion of Shp2 in spermatogonia caused many meiotic spermatocytes to die; moreover, the surviving spermatocytes reached the leptotene stage early at postnatal day 9 (PN9) and the pachytene stage at PN11-13. In preleptotene spermatocytes, Shp2 deletion disrupted the expression of meiotic genes, such as disrupted meiotic cDNA 1 (Dmc1), DNA repair recombinase rad51 (Rad51), and structural maintenance of chromosome 3 (Smc3), and these deficiencies interrupted spermatocyte meiosis. In GC-1 cells cultured in vitro, Shp2 knockdown suppressed the retinoic acid (RA)-induced phosphorylation of extracellular-regulated protein kinase (Erk) and protein kinase B (Akt/PKB) and the expression of target genes such as synaptonemal complex protein 3 (Sycp3) and Dmc1. Together, these data suggest that Shp2 plays a crucial role in spermatogenesis by governing the transition from spermatogonia to spermatocytes and by mediating meiotic progression through regulating gene transcription, thus providing a potential treatment target for male infertility.

G Protein–Coupled Receptor 30 Mediates the Anticancer Effects Induced by Eicosapentaenoic Acid in Ovarian Cancer Cells / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#While numerous epidemiological studies have indicated that omega-3 polyunsaturated fatty acids have anticancer properties in various cancers, the effects and mechanisms of eicosapentaenoic acid (EPA) in ovarian cancer cell growth are poorly understood. @*Materials and Methods@#ES2 ovarian clear cell carcinoma cells and SKOV3 adenocarcinoma cells were treated with palmitic acid or EPA, followed by flow cytometry and cell counting to measure apoptosis and proliferation, respectively. A modified protein lipid overlay assay was used to further verify whether EPA was a ligand of G protein–coupled receptor 30 (GPR30) in ES2 cells. The levels of apoptosis-related genes, phosphorylated AKT, and phosphorylated ERK1/2 were detected to explore the underlying mechanism. Finally, inhibitory effect of EPA on tumor growth via GPR30 was determined in vitro and in vivo. @*Results@#EPA suppressed ES2 ovarian clear cell carcinoma cells growth via GPR30, a novel EPA receptor, by inducing apoptosis. As a ligand of GPR30, EPA activated the GPR30-cAMP– protein kinase A signaling pathway. When GPR30 was suppressed by siRNA or its inhibitor G15, the antiproliferative action of EPA was impaired. Furthermore, EPA inhibited tumor growth by blocking the activation of AKT and ERK. In the mouse xenograft model, EPA decreased tumor volume and weight through GPR30 by blocking tumor cell proliferation. @*Conclusion@#These results confirm that EPA is a tumor suppressor in human ovarian clear cell carcinoma cells and functions through a novel fatty acid receptor, GPR30, indicating a mechanistic linkage between omega-3 fatty acids and cancers.

Comparative observation of protective effects of earplug and barrel on auditory organs of guinea pigs exposed to experimental blast underpressure / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To explore the protective effects of earplug and barrel on auditory organs of guinea pigs exposed to experimental blast underpressure (BUP).</p><p><b>METHODS</b>The hearing thresholds of the guinea pigs were assessed with auditory brainstem responses (ABR). The traumatic levels of tympanic membrane and ossicular chain were observed under stereo-microscope. The rate of outer hair cells (OHCs) loss was analyzed using a light microscope. The changes of guinea pigs protected with barrel and earplug were compared with those of the control group without any protection.</p><p><b>RESULTS</b>An important ABR threshold shift of the guinea pigs without any protection was detected from 8h to 14d after being exposed to BUP with a peak ranging from -64.5 kPa to -69.3 kPa ( P<0.01). The rate of perforation of tympanic membrane reached 87.5% and that of total OHCs loss was 19.46% +/- 5.38% at 14d after exposure. The guinea pigs protected with barrel and earplug had lower ABR threshold and total OHCs loss rate compared with the animals without any protection (P<0.01). All of the tympanic membrane and ossicular chain of the protected animals maintained their integrities. Meanwhile, the guinea pigs protected with the barrel had lower ABR threshold and total OHCs loss rate than those with earplug (P<0.01).</p><p><b>CONCLUSIONS</b>The earplug and barrel have protective effects against BUP-induced trauma on auditory organs of the guinea pigs and the protective effects of barrel are better than those of earplug.</p>

Mechanisms of action of transportation of liposomes and chitosan-coated liposomes containing leuprolide across intestine and Caco-2 cell / 药学学报

<p><b>AIM</b>To investigate the mechanisms of action of transportation of liposomes and chitosan-coated liposomes containing leuprolide across rat intestine and Caco-2 cell.</p><p><b>METHODS</b>Everted-gut technique and Caco-2 cell were used to study the transport properties of free leuprolide, liposomes and chitosan-coated liposomes containing leuprolide. Caco-2 cell was used to study the effect of chitosan concentration and the order of addition on the permeation of liposomes.</p><p><b>RESULTS</b>The transport of leuprolide was passive diffusion. Probably because the entrapment by liposomes prevents the transport of leuprolide across the rat intestine and Caco-2 cell, the permeation amount of leuprolide from liposomes was lower than that of the free drug. However, liposomes protected the leuprolide from degradation. Chitosan promoted the transport of leuprolide from liposomes and there was no obvious difference in enhancement effect from the concentration of 0.1% to 0.5%. On the other hand, the incubation of chitosan with liposomes may weak the enhancement effect of chitosan.</p><p><b>CONCLUSION</b>Chitosan-coated liposomes showed both protection and enhancement effect, therefore, they may promote the oral absorption of leuprolide.</p>

Study on trauma of tympanic membrane and ossicular chain of guinea pigs exposed to experimental blast underpressure / 中华创伤杂志

Objective To probe into the characteristics of traumatic effect of blast underpressure (BUP) on tympanic membrane and ossicular chain of guinea pigs exposed to blast underpressure. Methods The guinea pigs were exposed to experimental BUP generated by the underpressure generator and their tympanic membranes and auditory ossicules were observed with stereo-microscope.Results Most of the tympanic membranes in 72 guinea pigs (141 ears) presented with traumatic changes,such as engorgement,haemorrhage,epidermic desquamation and perforation,combined with fracture of ossicles in some guinea pigs.The traumatic severity of the tympanic membranes and auditory ossicules was related to the peak and the declinating duration of BUP.The minimum peak of the underpressure inducing perfo- ration was between-22.4kPa and-23.9kPa and the minimum peak inducing perforation of all the tym- panic membranes was between-83.1kPa and-87.2kPa.Conclusion The tympanic membrane in guinea pigs exposed to BUP changed traumatically,such as engorgement,haemorrhage,epidermic des- quamation,perforation and fracture of ossicles.The traumatic severity of the tympanic membranes and au- ditory ossicules is related to the peak and declinating duration of BUP.