piRNA在生殖系统中的功能研究进展

piRNA（Piwi—interacting RNA）是2006年发现的一种新的小RNA，长度约24到30个核苷酸，其作用与Dicer酶无关．与Piwi蛋白家族成员相结合才能发挥作用。目前研究piRNA的功能都基本限定在生殖细胞中，近来研究表明piRNA对于生殖细胞功能的很多环节有巨大的影响，而且对生殖支持细胞的影响的研究也有了进展。本文就piRNA在生殖系统中的功能的研究进展作一综述。     

PIWI蛋白相互作用RNA与生殖功能的关系

PIWI蛋白相互作用RNA(PIWI-interacting RNA,piRNA)是长度大约有24～31个核苷酸的非编码RNA,特异性表达于动物的生殖细胞中。piRNA的生成过程可分为细胞核内的转录以及细胞质内的后期加工两部分。piRNA可以在PIWI家族蛋白的协助下发挥沉默转座子基因和调控mRNA等功能,并可进一步调控生殖功能。在雄性生殖功能中,piRNA可以在PIWI家族蛋白的协助下通过控制组蛋白泛素连接酶RNF8、谷胱甘肽过氧化物酶5等蛋白的表达调控精子发生,引起无精子症、少精子症和弱精子症等影响雄性生殖功能的疾病。在piRNA最初的研究中,学者普遍认为piRNA在雌性生殖方面作用不大,但是近年对金黄地鼠的研究发现piRNA/PIWI复合物在雌性生殖功能的调控过程中也发挥着重要作用。综述piRNA的产生及其与生殖功能的相关性。     

非编码RNA与哺乳动物生殖细胞生长发育

基因转录后调控是表观遗传学的主要内容,是指通过DNA层面的修饰使原来拥有相同基因型的不同组织或细胞呈现出不同的表型和功能。非编码RNA作为此表观遗传调控的主要执行者之一,能够在转录水平调控蛋白质丰度,在生殖系统中更是发挥了基础调节者的作用。广义的非编码RNA包含了rRNA、tRNA、微小RNA（miRNA）、小干扰RNA（siRNA）、Piwi蛋白相互作用的RNA（piRNA）和长链非编码RNA（lncRNA）等。由于rRNA、tRNA已被人们较为熟知,文章主要选取miRNA、siRNA、piRNA等非编码RNA,针对其近期的研究进展,阐述该类非编码RNA在哺乳动物生殖细胞中的表达以及对生殖细胞发生、成熟的影响及作用机制。与此同时,还对另一类非编码RNA——lncRNA做基本的介绍。     

非编码RNA在生殖调节中的研究进展

非编码RNA（ncRNAs）在高等生物体内大量存在,组成十分复杂的生物调控网络,是目前生物医学领域的研究热点。小干扰RNA（siRNA）、微小RNA（miRNA）和PIWI相互作用RNA（piRNA）作为细胞内基因调控网络的重要成员影响细胞的各种生命活动。近年研究表明,ncRNA通过沉默转座元件和调控编码基因等方式在生殖细胞发育、分化、凋亡及激素合成的调控过程中发挥重要作用,ncRNA的异常表达与多囊卵巢综合征（PCOS）和卵巢功能早衰（POF）等生殖疾病密切相关。综述ncRNA在卵泡和胚胎发育以及精子生成等方面的作用及其研究进展。     

piRNA在双酚A促进前列腺癌细胞侵袭和迁移中的作用机制研究

目的研究PIWI蛋白相互作用RNA(piRNA)在双酚A(BPA)促进前列腺癌细胞侵袭和迁移中的作用机制。方法利用癌症基因组图谱(TCGA)数据, 分析并筛选在前列腺癌组织中表达显著升高的piRNA。使用不同浓度BPA对前列腺癌PC-3细胞进行12、24和48 h染毒, 结合CCK-8实验确定20%抑制浓度(IC20), 并使用实时荧光定量PCR检测BPA染毒前后piRNA表达水平的改变。随后利用比较毒理基因组学数据库(CTD)筛选受BPA调控且与前列腺癌相关的靶基因, 经双荧光素酶报告基因实验验证piRNA与靶基因的靶向调控关系, 并通过Western blotting检测piRNA靶基因的表达水平, 并进行细胞侵袭和迁移实验探究piRNA及其拮抗剂对PC-3细胞恶性表型的影响。结果 160 μmol/L BPA处理PC-3细胞piR-sno48表达水平升高幅度较大(P<0.05)。转染piR-sno48拮抗剂可导致内源性piR-sno48表达下降及其靶基因GSTP1表达水平升高(P<0.05), 但是BPA染毒的细胞中GSTP1表达未见明显改变(P>0.05)。双...     

端粒酶生物学作用及活性调节

自Blackbum等在二十世纪八十年代先后发现了端粒、端粒酶以后，对它的研究已成为肿瘤学、毒理学、生殖遗传学等研究领域的热门课题。现已证明：端粒酶是一种由RNA和蛋白质组成的核糖核蛋白复合体，具有逆转录酶活性。它在正常组织细胞中不表达，仅在生殖细胞、干细胞、肿瘤细胞中表达。许多研究表明，端粒酶与细胞增殖、细胞衰老和生殖功能的稳定关系密切，因此近十多年来，     

非编码RNA在生殖调节中的研究进展

非编码RNA(ncRNAs)在高等生物体内大量存在,组成十分复杂的生物调控网络,是目前生物医学领域的研究热点。小干扰RNA(siRNA)、微小RNA(miRNA)和PIWI相互作用RNA(pi RNA)作为细胞内基因调控网络的重要成员影响细胞的各种生命活动。近年研究表明,ncRNA通过沉默转座元件和调控编码基因等方式在生殖细胞发育、分化、凋亡及激素合成的调控过程中发挥重要作用,ncRNA的异常表达与多囊卵巢综合征(PCOS)和卵巢功能早衰(POF)等生殖疾病密切相关。综述ncRNA在卵泡和胚胎发育以及精子生成等方面的作用及其研究进展。     

微小RNA在生殖发育领域中的研究进展

微小RNA（micro RNA,miRNA）是一类新发现的非编码的调控RNA,其主要在转录水平或转录后水平上发挥调控效应,控制着生长发育、分化、代谢和疾病等许多生物过程。miRNA调控精子与卵子的减数分裂,影响配子的生长发育。参与植入前小鼠胚胎早期发育时序的调节,干预植入过程中相关基因的表达。而且涉及到干细胞的自我更新与多潜能性的维持,控制多能胚胎干细胞潜系的决定。生殖细胞miRNA的异常表达与生育能力障碍存在一定相关性。就miRNA相关机制和功能,主要检测方法及其在生殖发育领域中研究进展综述。     

微小RNA在生殖发育领域中的研究进展

微小RNA（micro RNA, miRNA）是一类新发现的非编码的调控RNA,其主要在转录水平或转录后水平上发挥调控效应,控制着生长发育、分化、代谢和疾病等许多生物过程。miRNA调控精子与卵子的减数分裂,影响配子的生长发育。参与植入前小鼠胚胎早期发育时序的调节,干预植入过程中相关基因的表达。而且涉及到干细胞的自我更新与多潜能性的维持,控制多能胚胎干细胞谱系的决定。生殖细胞miRNA的异常表达与生育能力障碍存在一定相关性。就miRNA相关机制和功能,主要检测方法及其在生殖发育领域中研究进展综述。     

哺乳动物RNA干扰中的小干扰RNA表达载体

载体表达小干扰RNA的方法因便宜,稳定,操作方便的优点,在哺乳动物RNA干扰研究中有非常大的潜力和优势。本文对当前哺乳动物RNA干扰研究中的小干扰RNA表达用载体作一综述。小干扰RNA载体表达方法的广泛应用,将对功能基因组研究以及抗病毒和肿瘤的基因治疗产生深远的影响。     

Serum levels of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) in relation to markers of reproductive function in young males from the general Swedish population

A time-related deterioration in male reproductive function caused by exposure to endocrine disrupters, including persistent organochlorines (POCs), has been hypothesized. In animal studies, POCs were found to have adverse effects on male reproductive function. However, little is known about the impact of POC exposure on reproductive parameters in men. In a study of 305 young Swedish men 18-21 years old from the general population, we correlated lipid-adjusted serum levels of 2,2',4,4',5,5' -hexachlorobiphenyl (CB-153)--an index substance for POC exposure--to markers of male reproductive function: testis size assessed by ultrasound, sperm concentration, total sperm count, sperm motility assessed manually and with a computer-aided sperm analyzer (CASA), and serum levels of follicle-stimulating hormone, inhibin B, testosterone, sexual hormone-binding globulin (SHBG), luteinizing hormone, and estradiol. We found weak but statistically significant, negative correlations between CB-153 levels and both the testosterone:SHBG ratio (r = -0.25, p < 0.001)--a measure of the biologically active free testosterone fraction--and CASA sperm motility (r = -0.13, p = 0.02). No statistically significant association with other seminal, hormonal, or clinical markers of male reproductive function was found. In previous studies of more highly POC-exposed groups of adult men, the correlation between POC exposure, including CB-153, and free testosterone levels was not statistically significant. The present study gives some tentative support for weak negative effects of CB-153 exposure on sperm motility and free testosterone levels in young men, but further semen studies on more highly exposed groups may give more firm conclusions on the hazard for male reproductive function from dietary POC exposure.     

Sampling strategies for prospective studies of menstrual function

Little information is available about optimal sampling strategies for prospective studies of menstrual function. Sample size and study duration for menstrual studies have often been driven as much by feasibility and cost as by statistical principles, with follow-up lasting 6 months to 2 years and sample size ranging from 100 to 500 women. Whether these studies are sufficiently powered to address common study objectives has not been adequately evaluated, and sample size estimates rarely account for the repeated nature of menstrual cycle data. Using data from the Tremin Trust (a study of menstrual function across the reproductive life span initiated in Minneapolis, Minnesota, in 1935 with data collected through 1977), the authors determined sampling strategies for assessing differences in mean cycle length between two exposure groups and for assessing change in mean cycle length across the reproductive life span. Following a larger number of women for 1-2 years is optimal for studies of host and environmental exposures that alter menstrual function. In contrast, following fewer women for an extended period of time, for example, 4-5 years, is optimal when studying how menstrual patterns vary across the reproductive life span in different populations.     

Epidemiology of male reproductive function: a field searching for tools

BACKGROUND: An increase in the frequency of disorders of the male human reproductive organs has been described over recent decades. Neither its causes nor its consequences on fecundity, the ability of the couples to produce a live child, are clearly known. This lack of knowledge may partly be due to methodological difficulties specific to reproductive epidemiology. METHODS: We discuss the relevance and limits of some markers of the male aspects of human reproduction, focusing on semen parameters and fecundability, a measure of the probability of pregnancy. RESULTS: Semen parameters are associated with fecundability, although they have a relatively low sensitivity to detect couples with low fecundability. The study of semen parameters proved central to describe the influence of environmental factors on the male side of reproductive function. The main limitation of semen studies is low participation rates and the possible selection biases ensuing. Fecundability can be estimated by collecting waiting time to pregnancy. Its assessment in retrospective studies often excludes the least fecund, those couples remaining childless, which entails a bias and a decrease in statistical power. The prospective approach and an approach relying on the enrollment of a cross-sectional sample of the couples currently trying to obtain a pregnancy (current duration approach) do not have these limitations. Although it has never been used, the assessment of fecundability using the current duration approach is promising both for aetiologic research and monitoring. CONCLUSION: Most of the potential markers of male reproductive function are not assessed in the general population of France, with the exception of the incidence rate of testis cancer, which is currently increasing. We present some alternatives for a monitoring system of reproductive function.     

SARS-CoV-2 Nsp16蛋白分子特征及其对男性生殖功能潜在影响

目的 COVID-19可能并发生殖功能损伤的问题已引起关注.本研究分析SARS-CoV-2 Nsp16蛋白遗传特征、分子结构与生物功能,探讨病毒侵入睾丸组织后Nsp16对生殖细胞的潜在影响,为该病发病机制和治疗策略研究奠定基础.方法 应用生物信息技术和国际生物数据库,分析nsp16基因变异性、Nsp16空间结构与功能及...     

Male reproductive health in relation to occupational exposure to endocrine disrupting and other potent chemicals, a review of the epidemiologic literature

The line of research focusing on the human, especially male, reproductive system in relation to occupational exposure has diversified since the infiltration of the concept of endocrine disrupting chemicals (EDC), early in the 1990s. The main stream, until then, was the study of reproductive toxicity caused by single albeit relatively heavy exposures to chemicals of limited range (conventional scheme). The new and increasingly important stem is the search for a wider range of chemicals with endocrine disrupting potential, and health effects due to multiple low-dose exposures of potent chemicals (new scheme). There are also studies having aspects of both the conventional and new schemes. For studies with the new scheme, progress has been made in areas such as adherence to standardized techniques in evaluating male reproductive function and more sensitive study designs. Indeed, some studies have suggested the presence of EDCs in the occupational setting. However, epidemiological findings are still constrained by difficulties in the identification of occupationally-exposed populations and evaluation of exposure. There is thus a need for convergence of knowledge and a widening of the scope of epidemiological research targeting occupationally exposed populations under a carefully-designed protocol.     

NEW HOPE FOR INFERTILITY THERAPY: FABRICATING GAMETES FROM STEM CELLS

The field of reproductive and developmental biology has been revolutionized by recent advanced studies. These studies indicate that stem cells are capable of forming gametes in vivo and in vitro in both mouse and human. This has provided powerful tools for undertaking new types of reproductive studies, and particularly might provide new technology and novel approaches in assisted reproductive medicine.     

Effects of radiofrequency electromagnetic fields on mammalian spermatogenesis

This article reviews studies about the effects of radiofrequency electromagnetic (RF EM) fields on male reproductive system and reproductive health in mammals. According to current data, there are almost 4 million active mobile phone lines in Croatia while this number has risen to 2 billion in the world. Increased use of mobile technology raises scientific and public concern about possible hazardous effects of RF fields on human health. The effects of radiofrequencies on reproductive health and consequences for the offspring are still mainly unknown. A number of in vivo and in vitro studies indicated that RF fields could interact with charged intracellular macromolecular structures. Results of several laboratory studies on animal models showed how the RF fields could affect the mammalian reproductive system and sperm cells. Inasmuch as, in normal physiological conditions spermatogenesis is a balanced process of division, maturation and storage of cells, it is particularly vulnerable to the chemical and physical environmental stimuli. Especially sensitive could be the cytoskeleton, composed of charged proteins; actin, intermedial filaments and microtubules. Cytoskeleton is a functional and structural part of the cell that has important role in the sperm motility, and is actively involved in the morphologic changes that occur during mammalian spermiogenesis.     

Reproductive toxicity of metals in men

A combination of genetic, environmental and lifestyle factors contributes to adverse effects on the reproductive health in men. Metals are pervasive in food, water, air, tobacco smoke, and alcoholic beverages. Experimental studies suggest that many metals have adverse effects on the male reproductive function. However, information about reproductive effects of human exposure to metals is scarce and/or inconsistent. This review summarises the information from epidemiological studies of the effects of metal exposure on reproductive function in men. Factors capable of affecting these relationships were identified and discussed. A particular attention is given to the studies considering influence of concomitant exposure to various metals. These studies have generally confirmed that even moderate- to low-level exposure to lead affects certain reproductive parameters, and that exposure to cadmium affects the prostate function and serum testosterone levels. Adverse effects of mercury, manganese, chromium and arsenic on semen quality and altered serum hormone are less well documented. There is no clear evidence that boron exposure may impair reproductive health in men. Only a few studies have investigated reproductive effects of concomitant exposure to several metals and controlled for potential confounders. Future studies should consider the contribution of combined exposure to various metals and/or other factors that may influence individual susceptibility to reproductive health impairment in men.