CatSper蛋白对精子超活化运动和男性不育影响的研究进展

CtaSper通道是目前公认的哺乳动物精子细胞膜上最重要的Ca~(2+)通道,对精子运动、精子超活化和受精功能起着关键作用。Cat Sper蛋白只表达于精子尾部主段,由CatSper1-4和5个辅助单元β、γ、δ、ε和ζ构成。CatSper蛋白是Ca~(2+)功能结构域的主体,在时空上均有序调控精子尾部蛋白酪氨酸磷酸化(P-Tyr),维持了精子超活化运动。CatSper~(-/-)小鼠超活化表现为早发式、爆发式、散发式,能量很快耗尽,超活化提前终止。胞内p H值、膜电位、类固醇激素、多种蛋白质、环腺苷酸类似物等通过调控CatSper通道参与精子超活化、精子游动至受精部位和穿透卵子外膜。近年来,许多研究证实CatSper蛋白功能缺陷会严重影响精子功能,9个CatSper亚基的中任何一个丢失最终导致男性生育功能障碍。本文结合目前最新研究进展,从CatSper蛋白表达、定位、结构、调控等多角度就CatSper对精子超活化和男性不育的影响进行综述。     

精子超活化结构蛋白——Catsper表达特性研究

目的:Catsper是精子特有的一种阳离子通道蛋白,对于精子超活化有重要的调节作用,为进一步了解其表达特性,本文主要研究其组织特异性表达及表达规律。方法:运用RT-PCR和免疫组织化学方法分析Catsper在2~8周龄昆明小鼠睾丸、附睾等8种组织中的表达情况,在精子上的精确定位以及随发育阶段变化表达量的变化。结果:Catsper特异性地表达于睾丸和附睾组织上;主要定位于精子尾部的主段;Catsper的表达量受到发育阶段的调控,该蛋白表达量随个体发育周龄的增长而呈增加的趋势,于3周龄开始检测到它的表达,随后表达量显著增加至6周龄,以后逐渐增长至一个平台期。结论:小鼠的Catsper基因特异性地表达于睾丸和附睾上,并且主要位于精子尾部的主段,其表达量与小鼠的发育阶段有密切的关系。     

“益精方”对小鼠精子尾部特异性钙通道CatSper1的影响

目的:观察"益精方"对环磷酰胺所致少弱精子症模型小鼠精子尾部特异性钙通道CatSper1的影响。方法:将40只雄性昆明小鼠随机分为对照组(CG)、模型组(MG)、小剂量中药治疗组(SG)和大剂量中药治疗组(LG),按60mg/kg体重给CG小鼠腹腔注射生理盐水(NS),给MG、SG、LG小鼠腹腔注射环磷酰胺,每天1次,连续5d,第6d开始按体重分别给SG和LG小鼠灌服"益精方",剂量分别为人类常规用量(以60kg为标准)的1倍和5倍,MG小鼠给予等体积的NS灌胃,每天1次,连续34d,CG常规饲养,然后对小鼠进行精液常规分析,并用RT-PCR法检测小鼠精子CatSper1的表达。结果:CG、MG、SG和LG组小鼠附睾精子密度分别为(5.20±1.34)、(1.73±0.03)、(2.08±0.01)、(3.31±0.56)×106/ml,a+b级精子百分率分别为(14.49±0.30)%、(6.64±1.88)%、(11.99±1.01)%、(19.40±3.13)%,a+b+c级精子百分率分别为(68.39±15.13)%、(39.96±4.89)%、(62.28±4.43)%、(73.61±5.05)%,MG组精子密度、a+b级精子百分率、a+b+c级精子百分率显著低于CG组(P<0.05),经治疗后LG组精子密度、a+b级精子百分率、a+b+c级精子百分率明显增加,与MG组比较有显著性差异(P<0.05),而与CG组在a+b级精子百分率和a+b+c级精子百分率上没有明显区别。CatSper1的表达量在CG、MG、SG和LG组分别为0.76±0.05、0.73±0.03、0.75±0.12、0.85±0.04,LG组显著高于MG组(P<0.05),而与CG组比较没有明显区别。结论:腹腔注射环磷酰胺可使小鼠精子密度、a+b级精子百分率、a+b+c级精子百分率降低,CatSper1表达量下降,大剂量"益精方"可以通过提高CatSper1的表达量,增加小鼠精子密度、a+b级和a+b+c级精子百分率,从而达到治疗少弱精子症的目的。     

用SYBR Green I实时逆转录-聚合酶链反应定量检测人、小鼠精子中CatSper1 mRNA

目的：建立并优化SYBR GreenI实时RT-PCR体系,定量检测人、小鼠成熟精子中的CatSper1 mRNA。方法：用TRIzol分别提取人、小鼠成熟精子中的总RNA,逆转录后用SYBR GreenI实时PCR定量检测CatSper1 mRNA。SYBR GreenI实时PCR采用普通PCR试剂,加入SYBR GreenI染料,优化退火温度、Mg^2＋浓度及上、下游引物比例,并在PCR循环时采用四步法以消除引物二聚体的影响。优化完成后用不同浓度的精子cDNA为模板做标准曲线,以检测SYBR GreenI实时PCR的扩增效率。结果：定量检测CatSper1 mRNA的SYBR GreenI实时PCR体系适宜退火温度、Mg^2＋浓度及上、下游引物比例分别为63℃、3.0mmol/L和1∶1,四步法中采集荧光的温度为88℃。优化后用人和小鼠精子cDNA为模板做标准曲线分别为Y=-3.402log（X）＋25.99和Y=-3.409log（X）＋24.09,扩增效率分别为96.8%和96.5%,可定量检测人、小鼠成熟精子中的CatSper1 mRNA。结论：用普通的逆转录及PCR系统和试剂,建立了一种方便、廉价、可靠的SYBR GreenI实时荧光定量RT-PCR系统,可用于人、小鼠精子中CatSper1 mRNA定量检测。     

用SYBR Green I实时逆转录-聚合酶链反应定量检测人、小鼠精子中CatSper1 mRNA

目的:建立并优化SYBR GreenI实时RT-PCR体系,定量检测人、小鼠成熟精子中的CatSper1 mRNA。方法:用TRIzol分别提取人、小鼠成熟精子中的总RNA,逆转录后用SYBR GreenI实时PCR定量检测CatSper1 mRNA。SYBR GreenI实时PCR采用普通PCR试剂,加入SYBR GreenI染料,优化退火温度、Mg2+浓度及上、下游引物比例,并在PCR循环时采用四步法以消除引物二聚体的影响。优化完成后用不同浓度的精子cDNA为模板做标准曲线,以检测SYBR GreenI实时PCR的扩增效率。结果:定量检测CatSper1 mRNA的SYBR GreenI实时PCR体系适宜退火温度、Mg2+浓度及上、下游引物比例分别为63℃、3.0mmol/L和1∶1,四步法中采集荧光的温度为88℃。优化后用人和小鼠精子cDNA为模板做标准曲线分别为Y=-3.402log(X)+25.99和Y=-3.409log(X)+24.09,扩增效率分别为96.8%和96.5%,可定量检测人、小鼠成熟精子中的CatSper1 mRNA。结论:用普通的逆转录及PCR系统和试剂,建立了一种方便、廉价、可靠的SYBR GreenI实时荧光定量RT-PCR系统,可用于人、小鼠精子中CatSper1 mRNA定量检测。     

CatSper基因家族在人和小鼠组织中的表达特征

目的研究CatSper基因家族在人和小鼠组织中的分布特点。方法将不同发育阶段的小鼠睾丸组织cDNA与Affymetrix全基因组芯片探针进行杂交,筛选出差异表达基因CatSper基因家族。RT—PCR验证差异表达基因在不同发育阶段的小鼠睾丸组织的表达特征,及其在人和小鼠不同组织中的分布。结果基因芯片分析发现CatSper1、CatSper2和CatSper3在小鼠睾丸的表达呈阶段特异性。RT-PCR结果表明该基因家族在睾丸的表达丰度明显高于其它组织;CatSper1和CatSper4在人体睾丸组织中特异性表达。结论CatSper基因家族在人和小鼠中呈现睾丸特异性表达或高表达,可能在精子发生中发挥重要功能。     

真核表达CatSper1用于筛选有效siRNA的体外实验研究

目的 构建pEGFP-N1-CatSper1重组质粒,在真核细胞中表达CatSper1,利用化学合成siRNA抑制小鼠CatSper1基因的表达,并筛选抑制效果最佳的siRNA序列. 方法 利用重组PCR克隆小鼠CatSper1全长cDNA,构建到真核表达载体中.生物信息分析软件校正结果,获得三条针对雄性小鼠CatSper1的siRNA序列,合成后分别与重组质粒pEGFP-N1-CatSper1共转染到小鼠成神经瘤N2a细胞株中,通过观察EGFP荧光强度、实时定量聚合酶链反应和WesternBlot等方法,分析干扰效果,筛选能显著降低N2a细胞中外源性CatSper1表达量的siRNA序列. 结果 成功克隆小鼠CatSper1基因的全长cDNA片段（2,061 bp）,并构建到pEGFP-N1表达载体中.三个siRNA干扰组的CatSper1 mRNA和蛋白表达与空白对照组相比均下降,其中以靠近3＇端的siRNA干扰作用更为明显,阴性对照siRNA组未引起CatSper1 mRNA和CatSper1蛋白表达明显变化. 结论 在小鼠神经瘤N2a细胞株中成功表达外源性CatSper1蛋白,并筛选出有效的siRNA,为深入研究CatSper1功能及用于避孕提供参考.     

促发精子获能的分子机制

获能是精子在雌性生殖道中转运期间获得受精能力的过程。获能的分子机制相当复杂 ,目前尚未明确 ,但促发获能的起始分子事件已初步确定 ,包括精子细胞膜表面胆固醇外流、膜电位的改变、蛋白磷酸化等。本文综述了促发精子获能的分子机制及其研究前景。     

输精管吻合术后睾丸cAMP含量与精子密度的关系

日本大耳白雄兔３２只，随机分为输精管结扎组（ＶＧ）、输精管结扎－吻合组（ＶＡＧ）和假手术组（ＳＯＧ）。结果显示：ＶＡＧ的精子密度明显低于ＳＯＧ（Ｐ＜０．０１），并且与睾丸组织ｃＡＭＰ含量呈明显正相关（ｒ＝０．８４１，Ｐ＜０．０１）。血清睾酮水平３组无显著差异。ＶＧ，ＶＡＧ的睾丸重量均低于ＳＯＧ（Ｐ＜０．０１，Ｐ＜０．０５），但ＶＡＧ与ＶＧ比较有显著差异（Ｐ＜０．０５），且ＶＡＧ和ＳＯＧ的睾丸重量与精子密度也呈明显正相关（ｒ＝０．６９９，Ｐ＜０．０１）．说明输精管结扎及吻合后一段时间内睾丸生精功能处于相对抑制状态，且与对垂体促性腺激素反应性下降有关。     

可溶性腺苷酸环化酶介导精子获能及其信号转导通路

研究证明,精子中存在一种可溶性腺苷酸环化酶(sAC),在获能中起重要作用。精子获能过程中存在着Ca2+、cAMP及sAC的调节系统。本文综述sAC的来源、结构及其作用机制,旨在探讨sAC在精子获能过程中的作用及其信号转导通路。     

Panax ginseng induces the expression of CatSper genes and sperm hyperactivation

The cation channel of sperm （CatSper） protein family plays important roles in male reproduction and infertility. The four members of this family are expressed exclusively in the testis and are localized differently in sperm. To investigate the effects of Panax ginseng treatment on the expression of CatSper genes and sperm hyperactivation in male mice, sperm motility and CatSper gene expression were assessed using a computer-assisted semen analysis system, a Fluoroskan Ascent microplate fluorometer to assess Ca2＊ influx, real.time polymerase chain reaction, Western blotting and immunofluorescence. The results suggested that the Ca2＊ levels of sperm cells treated with P. ginseng were increased significantly compared with the normal group. The P. ginseng-treated groups showed increased sperm motility parameters, such as the curvilinear velocity and amplitude of lateral head displacement. Taken together, the data suggest that CatSper messenger ribonucleic acid levels were increased significantly in mouse testes in the P. ginseng-treated group, as was the protein level, with the exception of CatSper2. In conclusion, P. ginseng plays an important role in improving sperm hyperactivation via CatSper gene expression.     

Single Nucieotide Polymorphisms in a male infertility-related cene CatSper

Aim: To identify the single nucleotide polymorphisms (SNPs) of human CatSper gene, the mouse homologous gene product. Methods: A systematic screening of SNPs in coding regions and flanking intronic regions of human CatSper gene in a sample subset from 210 Chinese Han males by DNA sequencing was demonstrated. PCR single-strand conformation polymorphism (SSCP) analysis was used to determine the allele frequencies of the possible SNPs. Results: Three SNPs, including two novels, were identified and their allele frequencies determined in 210 males. These SNPs were assembled into large SNP database that permits the analysis of the genetic basis of different diseases.     

Effects of dioxin on testicular histopathology,sperm parameters,and CatSper2 gene and protein expression in Naval Medical Research Institute male mice

The CatSper gene family is known to be solely expressed in sperm cells and is possibly associated with sperm motility and penetration through the zona pellucida. Despite its vital role in male fertility, factors regulating its expression are not widely known. The present study aimed at evaluating the effects of dioxin on CatSper2 gene and protein expression, testicular histopathology, sperm quality and biochemical parameters in a mice model. The experiments were performed on 32 Naval Medical Research Institute male mice (2–3 months). The animals were divided into four groups in a random manner: (a) control; (b) dioxin 1; (c) dioxin 2; and (d) dioxin 3. The treatment groups received 0.1, 0.5 and 1 µg/kg of dioxin intraperitoneally every day for 2 weeks. Administration of dioxin significantly downregulated the CatSper2 gene and protein expression. A greater reduction in gene and protein expression was found at higher doses of dioxin. At the same time, sperm parameters, especially sperm motility and count, decreased in mice exposed to dioxin. The results of testicular histopathology showed necrotic degeneration and epithelium thickness reduction in the dioxin groups in comparison with the controls. Besides, oxidative stress increased in seminiferous tubules.     

CATSPER1蛋白与特发性弱精子症关系的研究

目的:探讨CATSPER1蛋白在特发性弱精子症发病中的作用。方法:采用非连续密度梯度离心分离精子,免疫细胞化学技术检测CATSPER1蛋白在特发性弱精子症患者精子中的定位及表达变化;同时用蛋白印迹技术检测CATSPER1蛋白在正常对照组及轻度弱精子症组、中度弱精子症组和重度弱精子症组中表达的差异,进行统计学分析。结果:CATSPER1蛋白定位于精子鞭毛主段;与正常对照组相比,CATSPER1在弱精子症患者中的表达下降,差异具有显著性(t=2.188,P=0.042);CATSPER1蛋白在正常对照组、轻度弱精子症组、中度弱精子症组和重度弱精子症组中的相对含量分别为(0.806±0.266)、(0.669±0.207)、(0.505±0.214)、(0.295±0.162),与对照组相比,CATSPER1蛋白相对表达量在各弱精子症组均存在不同程度的下降,差异存在显著性(P<0.05)。前向运动精子(a+b级)百分率与CATSPER1蛋白的含量成正相关(r=0.633,P=0.000)。结论:CATSPER1蛋白表达下降或异常可能是导致特发性弱精子症发生的一个环节。