Hspa4l-deficient mice display increased incidence of male infertility and hydronephrosis development

Protein disulfide isomerase is essential for spermatogenesis in mice

Spermatogenesis requires precise posttranslational control in the endoplasmic reticulum (ER), but the mechanism remains largely unknown. The protein disulfide isomerase (PDI) family is a group of thiol oxidoreductases responsible for catalyzing the disulfide bond formation of nascent proteins. In this study, we generated 14 strains of KO mice lacking the PDI family enzymes and found that only PDI deficiency caused spermatogenesis defects. Both inducible whole-body PDI-KO (UBC-Cre/Pdifl/fl) mice and premeiotic PDI-KO (Stra8-Cre/Pdifl/fl) mice experienced a significant decrease in germ cells, testicular atrophy, oligospermia, and complete male infertility. Stra8-Cre/Pdifl/fl spermatocytes had significantly upregulated ER stress-related proteins (GRP78 and XBP1) and apoptosis-related proteins (Cleaved caspase-3 and BAX), together with cell apoptosis. PDI deletion led to delayed DNA double-strand break repair and improper crossover at the pachytene spermatocytes. Quantitative mass spectrometry indicated that PDI deficiency downregulated vital proteins in spermatogenesis such as HSPA4L, SHCBP1L, and DDX4, consistent with the proteins' physical association with PDI in normal testes tissue. Furthermore, PDI served as a thiol oxidase for disulfide bond formation of SHCBP1L. Thus, PDI plays an essential role in protein quality control for spermatogenesis in mice.

Characterization of runs of homozygosity islands in American mink using whole-genome sequencing data

The genome-wide analysis of runs of homozygosity (ROH) islands can be an effective strategy for identifying shared variants within a population and uncovering important genomic regions related to complex traits. The current study performed ROH analysis to characterize the genome-wide patterns of homozygosity, identify ROH islands and annotated genes within these candidate regions using whole-genome sequencing data from 100 American mink (Neogale vison). After sequence processing, variants were called using GATK and Samtools pipelines. Subsequent to quality control, 8,373,854 bi-allelic variants identified by both pipelines remained for further analysis. A total of 34,652 ROH segments were identified in all individuals, among which shorter segments (0.3-1 Mb) were abundant throughout the genome, approximately accounting for 84.39% of all ROH. Within these segments, we identified 63 ROH islands housing 156 annotated genes. The genes located in ROH islands were associated with fur quality (EDNRA, FGF2, FOXA2 and SLC24A4), body size/weight (MYLK4, PRIM2, FABP2, EYS and PHF3), immune capacity (IL2, IL21, PTP4A1, SEMA4C, JAK2, CCNA2 and TNIP3) and reproduction (ADAD1, KHDRBS2, INSL6, PGRMC2 and HSPA4L). Furthermore, Gene Ontology and KEGG pathway enrichment analyses revealed 56 and 9 significant terms (FDR-corrected p-value < 0.05), respectively, among which cGMP-PKG signalling pathway, regulation of actin cytoskeleton, and calcium signalling pathway were highlighted due to their functional roles in growth and fur characteristics. This is the first study to present ROH islands in American mink. The candidate genes from ROH islands and functional enrichment analysis suggest possible signatures of selection in response to the mink breeding targets, such as increased body length, reproductive performance and fur quality. These findings contribute to our understanding of genetic characteristics, and provide complementary information to assist with implementation of breeding strategies for genetic improvement in American mink.

Regulation of Epithelial and Endothelial Barriers by Molecular Chaperones

The integrity and permeability of epithelial and endothelial barriers depend on the formation of tight junctions, adherens junctions, and a junction-associated cytoskeleton. The establishment of this junction-cytoskeletal module relies on the correct folding and oligomerization of its protein components. Molecular chaperones are known regulators of protein folding and complex formation in different cellular compartments. Mammalian cells possess an elaborate chaperone network consisting of several hundred chaperones and co-chaperones. Only a small part of this network has been linked, however, to the regulation of intercellular adhesions, and the systematic analysis of chaperone functions at epithelial and endothelial barriers is lacking. This review describes the functions and mechanisms of the chaperone-assisted regulation of intercellular junctions. The major focus of this review is on heat shock protein chaperones, their co-chaperones, and chaperonins since these molecules are the focus of the majority of the articles published on the chaperone-mediated control of tissue barriers. This review discusses the roles of chaperones in the regulation of the steady-state integrity of epithelial and vascular barriers as well as the disruption of these barriers by pathogenic factors and extracellular stressors. Since cytoskeletal coupling is essential for junctional integrity and remodeling, chaperone-assisted assembly of the actomyosin cytoskeleton is also discussed.

A first-in-class inhibitor of Hsp110 molecular chaperones of pathogenic fungi

Proteins of the Hsp110 family are molecular chaperones that play important roles in protein homeostasis in eukaryotes. The pathogenic fungus Candida albicans, which causes infections in humans, has a single Hsp110, termed Msi3. Here, we provide proof-of-principle evidence supporting fungal Hsp110s as targets for the development of new antifungal drugs. We identify a pyrazolo[3,4-b] pyridine derivative, termed HLQ2H (or 2H), that inhibits the biochemical and chaperone activities of Msi3, as well as the growth and viability of C. albicans. Moreover, the fungicidal activity of 2H correlates with its inhibition of in vivo protein folding. We propose 2H and related compounds as promising leads for development of new antifungals and as pharmacological tools for the study of the molecular mechanisms and functions of Hsp110s.

Expression of TXNRD1, HSPA4L and ATP1B1 Genes Associated with the Freezability of Boar Sperm

Cryopreservation is associated with increased oxidative stress, which is responsible for sperm damage. We analyzed the effect of cryopreservation on mRNA and protein expression of thioredoxin reductase 1 (TXNRD1), heat shock protein family A (HSP 70) member 4 like (HSPA4L) and sodium/potassium-transporting ATPase subunit beta-1 (ATP1B1) genes in boar sperm with different freezability. Boars were classified as having good and poor semen freezability (GSF and PSF, respectively), according to the assessment of post-thaw sperm motility. Total RNA was isolated from fresh pre-freeze (PF) and frozen-thawed (FT) sperm from five boars of the GSF and PSF groups, respectively. Quantification of TXNRD1, HSPA4L and ATP1B1 gene expression was performed by RT-qPCR analysis. Proteins extracted from sperm were subjected to Western blotting and SDS-PAGE analyses. Poor freezability ejaculates were characterized by significantly higher relative mRNA expression levels of TXNRD1 and HSPA4L in FT sperm compared with the fresh PF sperm. Furthermore, the relative mRNA expression level of ATP1B1 was significantly higher in the fresh PF sperm of the GSF group. Western blotting analysis revealed significantly higher relative expression of TXNRD1 protein in the fresh PF sperm of the GSF group, while HSPA4L protein expression was markedly increased in FT sperm of the PSF group. Electrophoretic and densitometric analyses revealed a higher number of proteins in the fresh PF and FT sperm of the PSF and GSF groups, respectively. The results of this study indicate that ATP1B1 mRNA expression in the fresh PF sperm is a promising cryotolerance marker, while the variations of TXNRD1 and HSPA4L protein expression in the fresh PF or FT sperm provide useful information that may help to elucidate their biological significance in cryo-damage.

Stress-induced perturbations in intracellular amino acids reprogram mRNA translation in osmoadaptation independently of the ISR

The integrated stress response (ISR) plays a pivotal role in adaptation of translation machinery to cellular stress. Here, we demonstrate an ISR-independent osmoadaptation mechanism involving reprogramming of translation via coordinated but independent actions of mTOR and plasma membrane amino acid transporter SNAT2. This biphasic response entails reduced global protein synthesis and mTOR signaling followed by translation of SNAT2. Induction of SNAT2 leads to accumulation of amino acids and reactivation of mTOR and global protein synthesis, paralleled by partial reversal of the early-phase, stress-induced translatome. We propose SNAT2 functions as a molecular switch between inhibition of protein synthesis and establishment of an osmoadaptive translation program involving the formation of cytoplasmic condensates of SNAT2-regulated RNA-binding proteins DDX3X and FUS. In summary, we define key roles of SNAT2 in osmotolerance.

Comparative transcriptome analysis of heat-induced domesticated zebrafish during gonadal differentiation

BACKGROUND

The influence of environmental factors, especially temperature, on sex ratio is of great significance to elucidate the mechanism of sex determination. However, the molecular mechanisms by which temperature affects sex determination remains unclear, although a few candidate genes have been found to play a role in the process. In this study, we conducted transcriptome analysis of the effects induced by high temperature on zebrafish during gonad differentiation period.

RESULTS

Totals of 1171, 1022 and 2921 differentially expressed genes (DEGs) between high temperature and normal temperature were identified at 35, 45 and 60 days post-fertilization (dpf) respectively, revealing that heat shock proteins (HSPs) and DNA methyltransferases (DNMTs) were involved in the heat-exposed sex reversal. The Gene Ontology (GO) terms and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway that were enriched in individuals after heat treatment included Fanconi anemia (FA) pathway, cell cycle, oocyte meiosis and homologous recombination.

CONCLUSIONS

Our study provides the results of comparative transcriptome analyses between high temperature and normal temperature, and reveals that the molecular mechanism of heat-induced masculinization in zebrafish is strongly related to the expression of HSPs and DNMTs and FA pathway during gonad differentiation.

Comparison of miRNA and mRNA Expression in Sika Deer Testes With Age

To elucidate the complex physiological process of testis development and spermatogenesis in Sika deer, this study evaluated the changes of miRNA and mRNA profiles in the four developmental stages of testis in the juvenile (1-year-old), adolescence (3-year-old), adult (5-year-old), and aged (10-year-old) stages. The results showed that a total of 198 mature, 66 novel miRNAs, and 23,558 differentially expressed (DE) unigenes were obtained; 14,918 (8,413 up and 6,505 down), 4,988 (2,453 up and 2,535 down), and 5,681 (2,929 up and 2,752 down) DE unigenes, as well as 88 (43 up and 45 down), 102 (44 up and 58 down), and 54 (18 up and 36 down) DE miRNAs were identified in 3- vs. 1-, 5- vs. 3-, and 10- vs. 5-year-old testes, respectively. By integrating miRNA and mRNA expression profiles, we predicted 10,790 mRNA-mRNA and 69,883 miRNA-mRNA interaction sites. The target genes were enriched by GO and KEGG pathways to obtain DE mRNA (IGF1R, ALKBH5, Piwil, HIF1A, BRDT, etc.) and DE miRNA (miR-140, miR-145, miR-7, miR-26a, etc.), which play an important role in testis development and spermatogenesis. The data show that DE miRNAs could regulate testis developmental and spermatogenesis through signaling pathways, including the MAPK signaling pathway, p53 signaling pathway, PI3K-Akt signaling pathway, Hippo signaling pathway, etc. miR-140 was confirmed to directly target mutant IGF1R-3'UTR by the Luciferase reporter assays. This study provides a useful resource for future studies on the role of miRNA regulation in testis development and spermatogenesis.

Novel function of the C-Terminal region of the Hsp110 family member Osp94 in unfolded protein refolding

Osp94, a member of the Hsp110/Sse1 family of heat shock proteins, has a longer C-terminus than Hsc70/Hsp70, composed of the loop region with partial SBDβ (L), and SBDα and the C-terminal extension (H), but the functions of these domains are poorly understood. Osp94 suppressed heat-induced aggregation of luciferase (Luc). Osp94-bound heat-inactivated Luc was reactivated in the presence of rabbit reticulocyte lysate (RRL) and/or a combination of Hsc70 and Hsp40. Targeted deletion mutagenesis revealed that the SBDβ and H domains of Osp94 are critical for protein disaggregation and RRL-mediated refolding. Reactivation of Hsp90-bound heat-inactivated Luc was abolished in the absence of RRL but compensated by PA28α, a proteasome activator. Interestingly, the LH domain also reactivated heat-inactivated Luc, independent of PA28α. Biotin-tag cross-linking experiments indicated that the LH domain and PA28α interact with Luc bound by Hsp90 during refolding. A chimera protein in which the H domain was exchanged for PA28α also mediated disaggregation and reactivation of heat-inactivated Luc. These results indicate that Osp94 acts as a holdase and that the C-terminal region plays a PA28α-like role in the refolding of unfolded proteins.

miR-434 and miR-242 have a potential role in heat stress response in rainbow trout (Oncorhynchus mykiss)

MicroRNAs (miRNAs) are being extensively studied as they function as key metabolic regulators which play a role in the heat stress response. However, the role of miRNAs in heat stress remains uncertain and many new miRNAs have not yet been discovered. In a previous study, we performed high-throughput sequencing of differentially expressed miRNAs identified on exposing rainbow trout (Oncorhynchus mykiss) to heat stress (18 vs. 24°C), which led to the identification of two novel miRNAs, temporarily named novel miR-434 and -242. The differential expression level of these miRNAs was extremely significant (P < 0.01); we analysed target gene mRNA transcripts by bioinformatics software (miRanda). We found novel miR-434 and -242 were predicted to regulate the transcripts of heat shock 70-kDa protein 4-like (HSPA4L) and calreticulin (CRT), respectively, by bioinformatics software. Here our core objective was to validate if HSPA4L and CRT are indeed the target genes of novel miR-434 and -242, respectively, and for this purpose we used the dual-luciferase reporter assay system. Target gene sequences were synthesized and cloned into a dual-luciferase vector. To better understand the function of the target genes, we combined the previous sequencing results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. We found that novel miR-434 regulated HSPA4L expression by binding to a putative binding site in the 3'-UTR of HSPA4L, and luciferase activity inhibition was observed. In contrast, novel miR-242 was not involved in regulating CRT expression. To conclude, we believe our results should serve as a foundation for future studies aiming to comprehensively understand the mechanisms used by rainbow trout to cope with heat stress.

Expressions of HSPA1L and HSPA9 are associated with poor sperm quality of low-motility spermatozoa in fertile men

Human semen is a heterogeneous group containing a portion of low-motility sperm, which may determine the sperm quality evaluation. Abnormally expressed proteins in low-motility spermatozoa will be the candidates for sperm biology research. By comparing proteomes of high- or low-motility spermatozoa from the same semen of normal fertile men, 21 differentially expressed proteins were identified. Proteins with molecular chaperone function were significantly over-represented, of which HSPA1L and HSPA9 significantly decreased in low-motility sperm. Compared with young adult testes with normal spermatogenesis, HSPA1L and HSPA9 had decreased expressions in elderly testis characterised with poor spermatogenesis, suggesting their associations with spermatogenesis. Decreased expressions of HSPA1L and HSPA9 in low-motility spermatozoa were validated by Western Blot and immunofluorescence quantification analysis. HSPA1L was mainly expressed on sperm post-acrosome and midpiece, whilst HSAP9 was mainly expressed on acrosome and sperm tail. HSPA1L antibody could inhibit sperm motility validated by antibody blocking experiment, whilst HSPA9 antibody showed no significant effect on sperm motility. The study demonstrated that low-motility spermatozoa from fertile men had poor sperm quality, in which differential expressed proteins were promising markers for evaluating sperm quality, understanding mechanism of male infertility with unexplained causes, and providing new idea for male infertility research.

Functional differences between Hsp105/110 family proteins in cell proliferation, cell division, and drug sensitivity

The mammalian HSP105/110 family consists of four members, including Hsp105 and Apg-1, which function as molecular chaperones. Recently, we reported that Hsp105 knockdown increases sensitivity to the DNA-damaging agent Adriamycin but decreases sensitivity to the microtubule-targeting agent paclitaxel. However, whether the other Hsp105/110 family proteins have the same functional property is unknown. Here, we show that Apg-1 has different roles from Hsp105 in cell proliferation, cell division, and drug sensitivity. We generated the Apg-1-knockdown HeLa S3 cells by lentiviral expression of Apg-1-targeting short hairpin RNA. Knockdown of Apg-1 but not Hsp105 decreased cell proliferation. Apg-1 knockdown increased cell death upon Adriamycin treatment without affecting paclitaxel sensitivity. The cell synchronization experiment suggests that Apg-1 functions in mitotic progression at a different mitotic subphase from Hsp105, which cause difference in paclitaxel sensitivity. Since Apg-1 is overexpressed in certain types of tumors, Apg-1 may become a potential therapeutic target for cancer treatment without causing resistance to the microtubule-targeting agents.

Heat shock protein A4L is a potent autoantigen for testicular autoimmunity in mice

Experimental autoimmune orchitis (EAO) may be used as a model to investigate immunological infertility in men. Murine EAO is induced via immunization with auto-immunogenic antigens (AIAgs) from testicular germ cells (TGCs). CD4 + T cells play a crucial role in EAO induction. However, whether AIAgs induce an immune response remains unclear. We aimed to identify self-antigens that induce EAO by screening a phage display library of random TGC peptides using IgG from EAO-induced A/J mice. Twenty TGC-specific AIAgs were detected, and G protein-coupled receptor kinase 2 interacting protein-1 (GIT1) and heat shock protein A4L (HSPA4L) were identified as candidate AIAgs that induce EAO. Immunization with GIT1 or HSPA4L, emulsified in complete Freund's adjuvant, resulted in 66 % or 100 % incidence of EAO, respectively, indicating that HSPA4L is a most potent AIAg that induces EAO in mice. These findings may expectedly help improve the diagnostic procedures and treatment of immunological infertility in men.

DNA variants are an unlikely explanation for the changing quality of spermatozoa within the same individual

It has recently been suggested that the human sperm genome is highly unstable, which may be a reasonable explanation as to why men, even fertile men, produce defective spermatozoa. Furthermore, an unstable genome may also explain why the semen profile of the same man changes from one ejaculate to the next. As such, we took multiple ejaculates (between 3 and 6) from 7 individuals over a 6-month period and isolated sperm through density gradients. We then compared the DNA of: (i) good and poor-quality spermatozoa within the same ejaculate; and (ii) from multiple ejaculates from the same individual. Our results suggest that on a global level, DNA present within spermatozoa is actually quite stable and similar between both good and poor sperm. This is important information for the assisted reproductive community when it comes to sperm selection.

Gene expression profiling of cultured mouse testis fragments treated with ethinylestradiol

The assessment of xenobiotic-induced testicular toxicity is important in drug development. Nonetheless, in vitro models to test drugs and chemicals that may cause testicular toxicity are lacking, requiring the continued use of animal models for those studies. We previously evaluated an in vitro mouse testis organ culture system using ethinylestradiol (EE), a well-studied testicular toxicant, and demonstrated a dose-dependent relationship between adverse effects to germ cell differentiation and increasing EE concentrations. However, we terminated that study after 20 days of culture due to oxygen deficiency during germ cell differentiation. Therefore, in the current study, we aimed to identify gene(s) with potential for supporting the histopathological evaluations of testicular toxicity using in vitro testis organ culture system. We cultured testis fragments obtained from mice at postnatal day (PND) 5 in α-Minimal Essential Medium containing 40 mg/mL AlbuMAX^™ I and treated them with 0.01 or 1 nM EE on day 1 of culture. On day 20, we collected testis fragments for RNA sequencing analysis and quantitative polymerase chain reaction (qPCR). We found that phospholipase C, zeta 1 and testis-specific serine kinase 4 genes, that are involved in spermatogenesis and predominantly expressed in the testis, were significantly reduced in testis fragments treated with the highest concentration of EE. Also, cytochrome P450, family 26, subfamily b, polypeptide 1 (Cyp26b1) and interleukin 16 (Il16) were up-regulated in the highest EE-treated groups. Further studies are needed to confirm the variations of these gene expression using other testicular toxicants.

iTRAQ-based proteomics analysis reveals the deregulated proteins related to liver toxicity induced by melamine with or without cyanuric acid in mice

The administration of melamine alone or its combination with cyanuric acid was shown to have certain liver toxicity. However, the injury mechanism of melamine-related toxicity to liver remains poorly understood. In the present study, we investigated the deregulated proteins related to liver toxicity induced by melamine with or without cyanuric acid in mice using iTRAQ quantitative proteomics technique. A total of 166 proteins were significantly changed by the melamine treatment, of which, 36 proteins were up-regulated and 130 proteins were down-regulated. Whereas, 242 proteins were significantly changed by the combined treatment of melamine and cyanuric acid, of which 81 proteins were up-regulated and 161 proteins were down-regulated. The enriched analysis of GO terms and KEGG pathway on the altered proteins showed that both enriched main GO terms and KEGG pathways appear to be different between the two kinds of treatments: melamine and mixture of melamine and cyanuric acid. Based on western blotting technique, it was confirmed that the expression of three proteins: heat shock protein 70 (HSP70), protein disulphide isomerase 6 (PDIA6) and heat shock 70 kDa protein 4-like (HSPA4L) were agreement with the findings in iTRAQ-Based quantitative analysis. These identified proteins might participate in the regulation of a wide range of biological processes, such as immune and inflammatory function, unfolded proteins response in endoplasmic reticulum, DNA damage, and the apoptosis of liver cells. These results from this study provide a new way to gain insight into the mechanisms of melamine-related toxicity to liver in animals.

Dephosphorylation of protamine 2 at serine 56 is crucial for murine sperm maturation in vivo

The posttranslational modification of histones is crucial in spermatogenesis, as in other tissues; however, during spermiogenesis, histones are replaced with protamines, which are critical for the tight packaging of the DNA in sperm cells. Protamines are also posttranslationally modified by phosphorylation and dephosphorylation, which prompted our investigation of the underlying mechanisms and biological consequences of their regulation. On the basis of a screen that implicated the heat shock protein Hspa4l in spermatogenesis, we generated mice deficient in Hspa4l (Hspa4l-null mice), which showed male infertility and the malformation of sperm heads. These phenotypes are similar to those of Ppp1cc-deficient mice, and we found that the amount of a testis- and sperm-specific isoform of the Ppp1cc phosphatase (Ppp1cc2) in the chromatin-binding fraction was substantially less in Hspa4l-null spermatozoa than that in those of wild-type mice. We further showed that Ppp1cc2 was a substrate of the chaperones Hsc70 and Hsp70 and that Hspa4l enhanced the release of Ppp1cc2 from these complexes, enabling the freed Ppp1cc2 to localize to chromatin. Pull-down and in vitro phosphatase assays suggested the dephosphorylation of protamine 2 at serine 56 (Prm2 Ser⁵⁶) by Ppp1cc2. To confirm the biological importance of Prm2 Ser⁵⁶ dephosphorylation, we mutated Ser⁵⁶ to alanine in Prm2 (Prm2 S56A). Introduction of this mutation to Hspa4l-null mice (Hspa4l ^-/-; Prm2 ^S56A/S56A) restored the malformation of sperm heads and the infertility of Hspa4l ^-/- mice. The dephosphorylation signal to eliminate phosphate was crucial, and these results unveiled the mechanism and biological relevance of the dephosphorylation of Prm2 for sperm maturation in vivo.

Identification and profiling of microRNAs during gonadal development in the giant freshwater prawn Macrobrachium rosenbergii

As post-transcriptional regulators, microRNAs (miRNAs) play an important role in growth and reproductive processes. So far, there is limited information regarding crustacean miRNAs. To explore the potential role of miRNAs in the gonadal development of the prawn Macrobrachium rosenbergii, we constructed seven small RNA libraries from ovarian and testicular tissues at various stages using somatic tissue as the control. A total of 1,954 known and 129 novel miRNAs were retrieved. By comparing differentially expressed miRNAs (DEMs) between testes and ovaries, forty-one miRNAs were identified with sex-biased expression patterns, including 17 ovary-biased and 24 testis-biased patterns. Furthermore, the putative target genes of the sex-biased miRNAs, such as cyclin L1, mitogen-activated protein kinase 7 (MAPK 7), heat shock protein (HSP), and zinc finger protein, were significantly enriched in many reproduction-related pathways including the Gonadotropin-releasing hormone (GnRH) pathway, glycolysis, gluconeogenesis pathway, ovarian steroidogenesis, estrogen signaling pathway, MAPK pathway, Wnt pathway, and insulin signaling pathway, implicating potential regulatory roles of miRNAs in reproduction. These data aid in the further investigation of the mechanism of gonadal development and reproductive regulation mediated by miRNA in M. rosenbergii.

Decreased expression of heat shock protein A4L in spermatozoa is positively related to poor human sperm quality

Heat shock protein A4L (HSPA4L), which is highly expressed in the testis, is correlated with male fertility. However, the relationship between HSPA4L expression and sperm quality remains unknown. In the present study, a systematic characterization of HSPA4L expression on spermatozoa was performed. HSPA4L is highly expressed in the human testis, characterized by abundant localization in testicular spermatocytes and round spermatids. Compared with the testis from young adults (aged 27-36 years old), downregulated expression of HSPA4L in the testis from elderly adults (aged 78-82 years old) was observed. Immunofluorescence quantification demonstrated the localization of HSPA4L in the middle piece of sperm. Compared with mature spermatozoa, a similar lower intensity and localization percentage of HSPA4L in immature and asthenozoospermic spermatozoa were observed, and the consistently decreased expression of HSPA4L in immature and asthenozoospermic spermatozoa was validated by western blot analysis. Functional analysis revealed a correlation between HSPA4L and sperm motility by Spearman correlation analysis and its involvement in sperm-oocyte penetration by the human sperm-hamster egg penetration test. The current study demonstrates that HSPA4L is a promising marker for the assessment of sperm quality and provides clues for exploring biomarkers for the molecular diagnosis and treatment of male infertility.

Developmental pathology of congenital kidney and urinary tract anomalies

Congenital anomalies of the kidneys or lower urinary tract (CAKUT) are the most common causes of renal failure in children and account for 25% of end-stage renal disease in adults. The spectrum of anomalies includes renal agenesis; hypoplasia; dysplasia; supernumerary, ectopic or fused kidneys; duplication; ureteropelvic junction obstruction; primary megaureter or ureterovesical junction obstruction; vesicoureteral reflux; ureterocele; and posterior urethral valves. CAKUT originates from developmental defects and can occur in isolation or as part of other syndromes. In recent decades, along with better understanding of the pathological features of the human congenital urinary tract defects, researchers using animal models have provided valuable insights into the pathogenesis of these diseases. However, the genetic causes and etiology of many CAKUT cases remain unknown, presenting challenges in finding effective treatment. Here we provide an overview of the critical steps of normal development of the urinary system, followed by a description of the pathological features of major types of CAKUT with respect to developmental mechanisms of their etiology.

Exome-wide Association Study Identifies GREB1L Mutations in Congenital Kidney Malformations

Renal agenesis and hypodysplasia (RHD) are major causes of pediatric chronic kidney disease and are highly genetically heterogeneous. We conducted whole-exome sequencing in 202 case subjects with RHD and identified diagnostic mutations in genes known to be associated with RHD in 7/202 case subjects. In an additional affected individual with RHD and a congenital heart defect, we found a homozygous loss-of-function (LOF) variant in SLIT3, recapitulating phenotypes reported with Slit3 inactivation in the mouse. To identify genes associated with RHD, we performed an exome-wide association study with 195 unresolved case subjects and 6,905 control subjects. The top signal resided in GREB1L, a gene implicated previously in Hoxb1 and Shha signaling in zebrafish. The significance of the association, which was p = 2.0 × 10^-5 for novel LOF, increased to p = 4.1 × 10^-6 for LOF and deleterious missense variants combined, and augmented further after accounting for segregation and de novo inheritance of rare variants (joint p = 2.3 × 10^-7). Finally, CRISPR/Cas9 disruption or knockdown of greb1l in zebrafish caused specific pronephric defects, which were rescued by wild-type human GREB1L mRNA, but not mRNA containing alleles identified in case subjects. Together, our study provides insight into the genetic landscape of kidney malformations in humans, presents multiple candidates, and identifies SLIT3 and GREB1L as genes implicated in the pathogenesis of RHD.

Expression and function of HSP110 family in mouse testis after vasectomy

HSP110 functions to protect cells, tissues, and organs from noxious conditions. Vasectomy induces apoptosis in the testis; however, little is known about the reason leading to this outcome. The aim of the present study was to evaluate the expression and function of HSP110 in mouse testis after vasectomy. Following bilateral vasectomy, we used fluorescent Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) to detect apoptosis, Western blotting and immunohistochemistry to examine HSP110 expression and localization. Serum antisperm antibody (AsAb) and testosterone were measured by Enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay, respectively. Expression of endoplasmic reticulum stress (ERS) sensors and downstream signaling components was measured by Reverse Transcription-Polymerase Chain Reaction (RT-PCR), and the phosphorylation of eIF2α and JNK was detected by Western blotting. Vasectomy induced morphologic changes, increased apoptosis in the testis, increased serum AsAb, and decreased testosterone levels. After vasectomy, ORP150 mRNA level was increased first and then decreased, Bcl-2 was decreased, and the expression of HSPA4l, GRP78, GADD153, PERK, ATF6, IRE-1, XBP-1s, Bax, Bak, and caspases and the phosphorylation of eIF2α and JNK were increased. We present that an ER stress-mediated pathway is activated and involved in apoptosis in the testis after vasectomy. HSPA4l and ORP150 may play important roles in maintaining the normal structure and function of testis.

Potential contributions of heat shock proteins and related genes in sexual differentiation in yellow catfish (Pelteobagrus fulvidraco)

Sex determination and differentiation in ectotherms are very complicated affairs and usually affected by both genetic and environmental factors. Because of their temperature-sensitive expression, heat shock proteins (HSPs) are good candidates for temperature-dependent sex determination (TSD). Similar to most thermosensitive fish species, the male to female ratio increases with temperature in yellow catfish (Pelteobagrus fulvidraco). Yellow catfish is also a type of sexual size dimorphic fish, and the male individuals grow much faster than females of the same age. Therefore, research of sex differentiation in yellow catfish is important in aquiculture. In this attempt, a total of seven HSPs and related genes were identified from transcriptomes of yellow catfish by 454 pyrosequencing and Solexa sequencing that we did previously, including five genes with complete open reading frame (ORF). Phylogenetically, all these genes were compared with their counterparts from other vertebrates. All these genes were sex-biased expressed in gonads. Hspa5, Hip, and Cdc37 were expressed more highly in ovary than in testis, whereas Hsp90α, Hspb2, Hspb8, and Hspbp1 were expressed more highly in testis than in ovary. Additionally, the expression of these genes was assessed after 17α-methyltestosterone (MT) and 17α-ethinylestradiol (EE2) treatment, respectively. Our result showed that working as co-chaperones, these HSPs and related genes may regulate sex steroid receptor activities to influence gonad development in yellow catfish. Our work would help in the understanding of the mechanism of sexual differentiation in teleosts.

Maternal common variant rs2305957 spanning PLK4 is associated with blastocyst formation and early recurrent miscarriage

OBJECTIVE

To investigate whether the common variant rs2305957 spanning PLK4 (Polo-like kinase 4) confers risk to embryo development in Northern Chinese Han (CHN) women.

DESIGN

Genetic association study.

SETTING

University hospital.

PATIENT(S)

A total of 2,015 infertile women who underwent in vitro fertilization (IVF), 530 women with early recurrent miscarriage (ERM), and 600 fertile control women in the CHN population.

INTERVENTION(S)

Genotyping of rs2305957 was performed by means of high-resolution melting analysis.

MAIN OUTCOME MEASURE(S)

Blastocyst formation, implantation, early miscarriage, and live birth rates in infertile women; genotype distribution at rs2305957 in ERM case and control subjects.

RESULT(S)

In the first cohort of this study, infertile women with AA genotype had a lower blastocyst formation rate than those with AG or GG genotype. No significant differences were observed in implantation rate, early miscarriage rate, or live birth rate among AA, AG, and GG subgroups. In the second cohort, common variant rs2305957 was related to ERM. Genotype frequency differences were also significant in both additive model and dominant model.

CONCLUSION(S)

Common variant rs2305957 is associated with blastocyst formation and ERM in CHN women. Further investigations of PLK4 gene during embryo development could be worthwhile.

Heat Shock Protein A2 (HSPA2): Regulatory Roles in Germ Cell Development and Sperm Function

Among the numerous families of heat shock protein (HSP) that have been implicated in the regulation of reproductive system development and function, those belonging to the 70 kDa HSP family have emerged as being indispensable for male fertility. In particular, the testis-enriched heat shock 70 kDa protein 2 (HSPA2) has been shown to be critical for the progression of germ cell differentiation during spermatogenesis in the mouse model. Beyond this developmentally important window, mounting evidence has also implicated HSPA2 in the functional transformation of the human sperm cell during their ascent of the female reproductive tract. Specifically, HSPA2 appears to coordinate the remodelling of specialised sperm domains overlying the anterior region of the sperm head compatible with their principle role in oocyte recognition. The fact that levels of the HSPA2 protein in mature spermatozoa tightly correlate with the efficacy of oocyte binding highlight its utility as a powerful prognostic biomarker of male fertility. In this chapter, we consider the unique structural and biochemical characteristics of HSPA2 that enable this heat shock protein to fulfil its prominent roles in orchestrating the morphological differentiation of male germ cells during spermatogenesis as well as their functional transformation during post-testicular sperm maturation.

Integrated proteomics and metabolomics analysis of rat testis: Mechanism of arsenic-induced male reproductive toxicity

Arsenic is a widespread metalloid in environment, whose exposure has been associated with a broad spectrum of toxic effects. However, a global view of arsenic-induced male reproductive toxicity is still lack, and the underlying mechanisms remain largely unclear. Our results revealed that arsenic exposure decreased testosterone level and reduced sperm quality in rats. By conducting an integrated proteomics and metabolomics analysis, the present study aims to investigate the global influence of arsenic exposure on the proteome and metabolome in rat testis. The abundance of 70 proteins (36 up-regulated and 34 down-regulated) and 13 metabolites (8 increased and 5 decreased) were found to be significantly altered by arsenic treatment. Among these, 19 proteins and 2 metabolites were specifically related to male reproductive system development and function, including spermatogenesis, sperm function and fertilization, fertility, internal genitalia development, and mating behavior. It is further proposed that arsenic mainly impaired spermatogenesis and fertilization via aberrant modulation of these male reproduction-related proteins and metabolites, which may be mediated by the ERK/AKT/NF-κB-dependent signaling pathway. Overall, these findings will aid our understanding of the mechanisms responsible for arsenic-induced male reproductive toxicity, and from such studies useful biomarkers indicative of arsenic exposure could be discovered.

Formation and function of the manchette and flagellum during spermatogenesis

The last phase of spermatogenesis involves spermatid elongation (spermiogenesis), where the nucleus is remodeled by chromatin condensation, the excess cytoplasm is removed and the acrosome and sperm tail are formed. Protein transport during spermatid elongation is required for correct formation of the sperm tail and acrosome and shaping of the head. Two microtubular-based protein delivery platforms transport proteins to the developing head and tail: the manchette and the sperm tail axoneme. The manchette is a transient skirt-like structure surrounding the elongating spermatid head and is only present during spermatid elongation. In this review, we consider current understanding of the assembly, disassembly and function of the manchette and the roles of these processes in spermatid head shaping and sperm tail formation. Recent studies have shown that at least some of the structural proteins of the sperm tail are transported through the intra-manchette transport to the basal body at the base of the developing sperm tail and through the intra-flagellar transport to the construction site in the flagellum. This review focuses on the microtubule-based mechanisms involved and the consequences of their disruption in spermatid elongation.

Differential Genes Expression between Fertile and Infertile Spermatozoa Revealed by Transcriptome Analysis

Background

It was believed earlier that spermatozoa have no traces of RNA because of loss of most of the cytoplasm. Recent studies have revealed the presence of about 3000 different kinds of mRNAs in ejaculated spermatozoa. However, the correlation of transcriptome profile with infertility remains obscure.

Methods

Total RNA from sperm (after exclusion of somatic cells) of 60 men consisting of individuals with known fertility (n=20), idiopathic infertility (normozoospermic patients, n=20), and asthenozoospermia (n=20) was isolated. After RNA quality check on Bioanalyzer, AffymetrixGeneChip Human Gene 1.0 ST Array was used for expression profiling, which consisted of >30,000 coding transcripts and >11,000 long intergenic non-coding transcripts.

Results

Comparison between all three groups revealed that two thousand and eighty one transcripts were differentially expressed. Analysis of these transcripts showed that some transcripts [ribosomal proteins (RPS25, RPS11, RPS13, RPL30, RPL34, RPL27, RPS5), HINT1, HSP90AB1, SRSF9, EIF4G2, ILF2] were up-regulated in the normozoospermic group, but down-regulated in the asthenozoospermic group in comparison to the control group. Some transcripts were specific to the normozoospermic group (up-regulated: CAPNS1, FAM153C, ARF1, CFL1, RPL19, USP22; down-regulated: ZNF90, SMNDC1, c14orf126, HNRNPK), while some were specific to the asthenozoospermic group (up-regulated: RPL24, HNRNPM, RPL4, PRPF8, HTN3, RPL11, RPL28, RPS16, SLC25A3, C2orf24, RHOA, GDI2, NONO, PARK7; down-regulated: HNRNPC, SMARCAD1, RPS24, RPS24, RPS27A, KIFAP3). A number of differentially expressed transcripts in spermatozoa were related to reproduction (n = 58) and development (n= 210). Some of these transcripts were related to heat shock proteins (DNAJB4, DNAJB14), testis specific genes (TCP11, TESK1, TSPYL1, ADAD1), and Y-chromosome genes (DAZ1, TSPYL1).

Conclusion

A complex RNA population in spermatozoa consisted of coding and non-coding RNAs. A number of transcripts that participate in a host of cellular processes, including reproduction and development were differentially expressed between fertile and infertile individuals. Differences between comparison groups suggest that sperm RNA has strong potential of acting as markers for fertility evaluation.

Impact of precise modulation of reactive oxygen species levels on spermatozoa proteins in infertile men

Background

Elevated levels of reactive oxygen species (ROS) are detected in 25% to 80% of infertile men. They are involved in the pathology of male infertility. Understanding the effect of increasing levels of ROS on the differential expression of sperm proteins is important to understand the cellular processes and or/pathways that may be implicated in male infertility. The aim of this study was to examine differentially expressed proteins (DEPs) in spermatozoa from patients with low, medium and high ROS levels.

Methods

A total of 42 infertile men presenting for infertility and 17 proven fertile men were enrolled in the study. ROS levels were measured by chemiluminescence assay. Infertile men were divided into Low (0- < 93 RLU/s/10⁶ sperm) (n = 11), Medium (>93-500 RLU/s/10⁶ sperm) (n = 17) and High ROS (>500 RLU/s/10⁶ sperm) group (n = 14). All fertile men had ROS levels between 4-50 RLU/s/10⁶ sperm. 4 subjects from fertile group and 4 each from the Low, Medium and High ROS were pooled. Protein extraction, protein estimation, gel separation of the proteins, in-gel digestion, LTQ-orbitrap elite hybrid mass spectrometry system was conducted. The DEPs, the cellular localization and pathways of DEPs involved were examined utilizing bioinformatics tools.

Results

1035 proteins were identified in the 3 groups by global proteomic analysis. Of these, 305 were DEPs. 51 were unique to the Low ROS group, 47 Medium ROS group and 104 were unique to the High ROS group. 6 DEPs were identified by Uniprot and DAVID that had distinct reproductive functions and they were expressed only in 3 ROS groups but not in the control.

Conclusions

We have for the first time demonstrated the presence of 6 DEPs with distinct reproductive functions only in men with low, medium or high ROS levels. These DEPs can serve as potential biomarkers of oxidative stress induced male infertility.

Electronic supplementary material

The online version of this article (doi:10.1186/1559-0275-12-4) contains supplementary material, which is available to authorized users.

Involvement of heat shock protein a4/apg-2 in refractory inflammatory bowel disease

BACKGROUND

Expression of heat shock protein A4 (HSPA4, also called Apg-2), a member of the HSP110 family, is induced by several forms of stress. The physiological and pathological functions of HSPA4 in the intestine remain to be elucidated.

METHODS

We assessed HSPA4 expression and function by generating HSPA4-deficient mice and using 214 human intestinal mucosa samples from patients with inflammatory bowel disease (IBD).

RESULTS

In the colonic mucosa of patients with IBD, a significant correlation was observed between the expression of HSPA4 and antiapoptotic protein Bcl-2, a T-cell-derived cytokine IL-17 or stem cell markers, such as Sox2. In refractory ulcerative colitis, a condition associated with increased cancer risk, expression of HSPA4 and Bcl-2 was increased in inflammatory cells of colonic mucosae. HSPA4 was overexpressed both in cancer cells and immune cells of human colorectal cancers. Patients with high expression of HSPA4 or Bmi1 showed significantly lower response rates upon subsequent steroid therapy as compared with patients with low expression of each gene. HSPA4-deficient mice exhibit more apoptosis and less expression of IL-17/IL-23 in inflammatory cells and less number of Sox2 cells after administration of dextran sodium sulfate than control mice. Transduction of HspaA4 bone marrow into wild-type mice reduced the immune response.

CONCLUSIONS

Upregulation of Bcl-2 and IL-17 by HSPA4 would control apoptosis of inflammatory cells and immune response in the gut, which might develop treatment resistance in IBD. HSPA4 and Bmi1 would be a useful biomarker for refractory clinical course and a promising approach for a therapeutic strategy in patients with IBD.

Identification of proteins involved in human sperm motility using high-throughput differential proteomics

Mammalian sperm motility is a prerequisite for in vivo fertilization, and alterations in this parameter are commonly observed in infertile males. However, we still do not have a complete understanding of the molecular mechanisms controlling it. The aim of this study was to identify proteins involved in human sperm motility deficiency by using TMT protein labeling and LC-MS/MS. Two complementary approaches were used: comparison between sperm samples differing in motility (asthenozoospermic versus normozoospermic) and comparison between sperm subpopulations of fractionated normozoospermic samples differing in motility (non-migrated versus migrated). LC-MS/MS resulted in the identification of 1157 and 887 proteins in the first and second approaches, respectively. Remarkably, similar proteomic alterations were detected in the two experiments, with 80 proteins differentially expressed in the two groups of samples and 93 differentially expressed in the two groups of subpopulations. The differential proteins were analyzed by GO, cellular pathways, and clustering analyses and resulted in the identification of core deregulated proteins and pathways associated with sperm motility dysfunction. These included proteins associated with energetic metabolism, protein folding/degradation, vesicle trafficking, and the cytoskeleton. Contrary to what is usually accepted, the outcomes support the hypothesis that several metabolic pathways (notably, mitochondrial-related ones) contribute toward regulating sperm motility.

Investigation and identification of etiologies involved in the development of acquired hydronephrosis in aged laboratory mice with the use of high-frequency ultrasound imaging

Laboratory mice develop naturally occurring lesions that affect biomedical research. Hydronephrosis is a recognized pathologic abnormality of the mouse kidney. Acquired hydronephrosis can affect any mouse, as it is caused by any naturally occurring disease that impairs free urine flow. Many etiologies leading to this condition are of particular significance to aging mice. Non-invasive ultrasound imaging detects renal pelvic dilation, renal enlargement, and parenchymal loss for pre-mortem identification of this condition. High-frequency ultrasound transducers produce high-resolution images of small structures, ideal for detecting organ pathology in mice. Using a 40 MHz linear array transducer, we obtained high-resolution images of a diversity of pathologic lesions occurring within the abdomen of seven geriatric mice with acquired hydronephrosis that enabled a determination of the underlying etiology. Etiologies diagnosed from the imaging results include pyelonephritis, neoplasia, urolithiasis, mouse urologic syndrome, and spontaneous hydronephrosis, and were confirmed at necropsy. A retrospective review of abdominal scans from an additional 149 aging mice shows that the most common etiologies associated with acquired hydronephrosis are mouse urologic syndrome and abdominal neoplasia. This report highlights the utility of high-frequency ultrasound for surveying research mice for age-related pathology, and is the first comprehensive report of multiple cases of acquired hydronephrosis in mice.

Expressions of miR-15a and its target gene HSPA1B in the spermatozoa of patients with varicocele

Hyperthermia and oxidative stresses are the two central elements contributing to varicocele-related sperm damage. Growing evidence indicates that microRNAs (miRNAs) are involved in the regulation of the heat and oxidative stress responses. In this study, we analyzed the expressions of several stress-related miRNAs in the sperm and found that the expression of miR-15a was significantly decreased in patients with varicocele compared with the control. Furthermore, miR-15a repressed the expression of HSPA1B, which is a typical stress-induced chaperone protein, through directly binding its 3'-UTR. The expressions of miR-15a and HSPA1B exhibited an inverse correlation in sperm. Our results provide a valuable insight into the varicocele-related sperm impairment and male infertility, and may help to develop potential therapeutic targets and novel biomarkers for male infertility.

TAp73 is essential for germ cell adhesion and maturation in testis

The p53 family member TAp73 is required for sperm maturation through promotion of adhesion between developing germ cells and Sertoli nurse cells.

A core evolutionary function of the p53 family is to protect the genomic integrity of gametes. However, the role of p73 in the male germ line is unknown. Here, we reveal that TAp73 unexpectedly functions as an adhesion and maturation factor of the seminiferous epithelium orchestrating spermiogenesis. TAp73 knockout (TAp73KO) and p73KO mice, but not ΔNp73KO mice, display a “near-empty seminiferous tubule” phenotype due to massive premature loss of immature germ cells. The cellular basis of this phenotype is defective cell–cell adhesions of developing germ cells to Sertoli nurse cells, with likely secondary degeneration of Sertoli cells, including the blood–testis barrier, which leads to disruption of the adhesive integrity and maturation of the germ epithelium. At the molecular level, TAp73, which is produced in germ cells, controls a coordinated transcriptional program of adhesion- and migration-related proteins including peptidase inhibitors, proteases, receptors, and integrins required for germ–Sertoli cell adhesion and dynamic junctional restructuring. Thus, we propose the testis as a unique organ with strict division of labor among all family members: p63 and p53 safeguard germ line fidelity, whereas TAp73 ensures fertility by enabling sperm maturation.

Adult glucocorticoid exposure leads to transcriptional and DNA methylation changes in nuclear steroid receptors in the hippocampus and kidney of mouse male offspring

Synthetic glucocorticoids (sGCs) are commonly prescribed for the management of inflammatory and endocrine disorders. However, nothing is known regarding the effects of sGC on adult germline methylome and whether these effects can be transmitted to the next generation. We hypothesized that administration of sGC to adult male mice alters DNA methylation in mature sperm and modifies the transcription and methylation of steroid receptors in male F1 offspring. Adult C57BL/6 males (n = 10/group) were injected on five consecutive days with 1 mg/kg sGC (i.e., dexamethasone) or vehicle and euthanized 35 or 60 days after initial treatment or bred with control females (60 days postinitial treatment; n = 5/group). A significant increase in global non-CpG methylation was observed in F0 sperm 60 days following sGC treatment. In the hippocampus and kidney of Postnatal Day 50 (PND50) and PND240 male offspring derived from fathers exposed to sGC, significant differences in mineralocorticoid receptor (Nr3c2; Mr), estrogen alpha receptor (Nr3a1; Ers1), and glucocorticoid receptor (Nr3c1; Gr) expression were observed. Furthermore, significant demethylation in regulatory regions of Mr, Gr, and Esr1 was observed in the PND50 kidney derived from fathers exposed to sGC. This is the first demonstration that paternal pharmacological exposure to sGC can alter the expression and DNA methylation of nuclear steroid receptors in brain and somatic tissues of offspring. These findings provide proof of principle that adult male exposure to sGC can affect DNA methylation and gene expression in offspring, indicating the possibility that adult experiences that evoke increases in endogenous glucocorticoid (i.e., stress) might have similar effects.

αTAT1 is the major α-tubulin acetyltransferase in mice

Post-translational modification of tubulin serves as a powerful means for rapidly adjusting the functional diversity of microtubules. Acetylation of the ε-amino group of K40 in α-tubulin is one such modification that is highly conserved in ciliated organisms. Recently, αTAT1, a Gcn5-related N-acetyltransferase, was identified as an α-tubulin acetyltransferase in Tetrahymena and C. elegans. Here we generate mice with a targeted deletion of Atat1 to determine its function in mammals. Remarkably, we observe a loss of detectable K40 α-tubulin acetylation in these mice across multiple tissues and in cellular structures such as cilia and axons where acetylation is normally enriched. Mice are viable and develop normally, however, the absence of Atat1 impacts upon sperm motility and male mouse fertility, and increases microtubule stability. Thus, αTAT1 has a conserved function as the major α-tubulin acetyltransferase in ciliated organisms and has an important role in regulating subcellular specialization of subsets of microtubules.

Linking spermatid ribonucleic acid (RNA) binding protein and retrogene diversity to reproductive success

Spermiogenesis is a postmeiotic process that drives development of round spermatids into fully elongated spermatozoa. Spermatid elongation is largely controlled post-transcriptionally after global silencing of mRNA synthesis from the haploid genome. Here, rats that differentially express EGFP from a lentiviral transgene during early and late steps of spermiogenesis were used to flow sort fractions of round and elongating spermatids. Mass-spectral analysis of 2D gel protein spots enriched >3-fold in each fraction revealed a heterogeneous RNA binding proteome (hnRNPA2/b1, hnRNPA3, hnRPDL, hnRNPK, hnRNPL, hnRNPM, PABPC1, PABPC4, PCBP1, PCBP3, PTBP2, PSIP1, RGSL1, RUVBL2, SARNP2, TDRD6, TDRD7) abundantly expressed in round spermatids prior to their elongation. Notably, each protein within this ontology cluster regulates alternative splicing, sub-cellular transport, degradation and/or translational repression of mRNAs. In contrast, elongating spermatid fractions were enriched with glycolytic enzymes, redox enzymes and protein synthesis factors. Retrogene-encoded proteins were over-represented among the most abundant elongating spermatid factors identified. Consistent with these biochemical activities, plus corresponding histological profiles, the identified RNA processing factors are predicted to collectively drive post-transcriptional expression of an alternative exome that fuels finishing steps of sperm maturation and fitness.

Expression of osmotic stress protein 94 in murine endolymphatic hydrops model

CONCLUSION

The up-regulation of osmotic stress protein 94 (OSP94) in the murine endolymphatic hydrops (EH) models suggests that OSP94 might be involved in cellular adaptation in response to ionic and osmotic stress in the murine inner ear.

OBJECTIVES

The purpose of the present study was to investigate the expression of OSP94 in cochlear tissues of the murine EH models and control animals.

METHODS

Nine adult BALB/c mice were treated with both intratympanic injection of lipopolysaccharide and intraperitoneal administration of aldosterone to induce EH. Nine mice were used as control animals. The expression level of OSP94 in the EH and control groups was compared using immunohistochemistry and real-time RT-PCR.

RESULTS

Immunohistochemical staining of tissues in the EH group showed an up-regulation of OSP94 expression in the cochlea, especially in the stria vascularis and Reissner's membrane. Quantitative real-time PCR analysis also showed that transcription of the OSP94 gene in the cochlea was significantly up-regulated in the EH group.

Activation of transcriptional activity of HSE by a novel mouse zinc finger protein ZNFD specifically expressed in testis

Zinc finger proteins (ZFPs) that contain multiple cysteine and/or histidine residues perform important roles in various cellular functions, including transcriptional regulation, cell proliferation, differentiation, and apoptosis. The Cys-Cys-His-His (C(2)H(2)) type of ZFPs are the well-defined members of this super family and are the largest and most complex proteins in eukaryotic genomes. In this study, we identified a novel C(2)H(2) type of zinc finger gene ZNFD from mice which has a 1,002 bp open reading frame and encodes a protein with 333 amino acid residues. The predicted 37.4 kDa protein contains a C(2)H(2) zinc finger domain. ZNFD gene is located on chromosome 18qD1. RT-PCR analysis revealed that the ZNFD gene was specifically expressed in mouse testis but not in other tissues. Subcellular localization analysis demonstrated that ZNFD was localized in the nucleus. Reporter gene assays showed that overexpression of ZNFD in the COS7 cells activates the transcriptional activities of heat shock element (HSE). Overall, these results suggest that ZNFD is a member of the zinc finger transcription factor family and it participates in the transcriptional regulation of HSE. Many heat shock proteins regulated by HSE are involved in testicular development. Therefore, our results suggest that ZNFD may probably participate in the development of mouse testis and function as a transcription activator in HSE-mediated gene expression and signaling pathways.

Mammalian meiosis is more conserved by sex than by species: conserved co-expression networks of meiotic prophase

Despite the importance of meiosis to human reproduction, we know remarkably little about the genes and pathways that regulate meiotic progression through prophase in any mammalian species. Microarray expression profiles of mammalian gonads provide a valuable resource for probing gene networks. However, expression studies are confounded by mixed germ cell and somatic cell populations in the gonad and asynchronous germ cell populations. Further, widely used clustering methods for analyzing microarray profiles are unable to prioritize candidate genes for testing. To derive a comprehensive understanding of gene expression in mammalian meiotic prophase, we constructed conserved co-expression networks by linking expression profiles of male and female gonads across mouse and human. We demonstrate that conserved gene co-expression dramatically improved the accuracy of detecting known meiotic genes compared with using co-expression in individual studies. Interestingly, our results indicate that meiotic prophase is more conserved by sex than by species. The co-expression networks allowed us to identify genes involved in meiotic recombination, chromatin cohesion, and piRNA metabolism. Further, we were able to prioritize candidate genes based on quantitative co-expression links with known meiotic genes. Literature studies of these candidate genes suggest that some are human disease genes while others are associated with mammalian gonads. In conclusion, our co-expression networks provide a systematic understanding of cross-sex and cross-species conservations observed during meiotic prophase. This approach further allows us to prioritize candidate meiotic genes for in-depth mechanistic studies in the future.

Osmoadaptation of Mammalian cells - an orchestrated network of protective genes

In mammals, the cells of the renal medulla are physiologically exposed to interstitial osmolalities several-fold higher that found in any other tissue. Nevertheless, these cells not only have the ability to survive in this harsh environment, but also to function normally, which is critical for maintenance of systemic electrolyte and fluid homeostasis. Over the last two decades, a substantial body of evidence has accumulated, indicating that sequential and well orchestrated genomic responses are required to provide tolerance to osmotic stress. This includes the enhanced expression and action of immediate-early genes, growth arrest and DNA damage inducible genes (GADDs), genes involved in cell cycle control and apoptosis, heat shock proteins, and ultimately that of genes involved in the intracellular accumulation of nonperturbing organic osmolytes. The present review summarizes the sequence of genomic responses conferring resistance against osmotic stress. In addition, the regulatory mechanisms mediating the coordinated genomic response to osmotic stress will be highlighted.

TLRR (lrrc67) interacts with PP1 and is associated with a cytoskeletal complex in the testis

BACKGROUND INFORMATION

Spermatozoa are formed via a complex series of cellular transformations, including acrosome and flagellum formation, nuclear condensation and elongation and removal of residual cytoplasm. Nuclear elongation is accompanied by the formation of a unique cytoskeletal structure, the manchette. We have previously identified a leucine-rich repeat protein that we have named TLRR (testis leucine-rich repeat), associated with the manchette that contains a PP1 (protein phosphatase-1)-binding site. Leucine-rich repeat proteins often mediate protein-protein interactions; therefore, we hypothesize that TLRR acts as a scaffold to link signalling molecules, including PP1, to the manchette near potential substrate proteins important for spermatogenesis.

RESULTS

TLRR and PP1 interact with one another as demonstrated by co-immunoprecipitation and the yeast two-hybrid assay. TLRR binds more strongly to PP1 gamma 2 than it does to PP1 alpha. Anti-phosphoserine antibodies immunoprecipitate TLRR from testis lysate, indicating that TLRR is a phosphoprotein. TLRR is part of a complex in testis that includes cytoskeletal proteins and constituents of the ubiquitin-proteasome pathway. The TLRR complex purified from 3T3 cells contains similar proteins, co-localizes with microtubules and is enriched at the microtubule-organizing centre. TLRR is also detected near the centrosome of elongated, but not mid-stage, spermatids.

CONCLUSION

We demonstrate here that TLRR interacts with PP1, particularly the testis-specific isoform, PP1 gamma 2. Immunoaffinity purification confirms that TLRR is associated with the spermatid cytoskeleton. In addition, proteins involved in protein stability are part of the TLRR complex. These results support our hypothesis that TLRR links signalling molecules to the spermatid cytoskeleton in order to regulate important substrates involved in spermatid transformation. The translocation of TLRR from the manchette to the centrosome region suggests a possible role for this protein in tail formation. Our finding that TLRR is associated with microtubules in cultured cells suggests that TLRR may play a common role in modulating the cytoskeleton in other cell types besides male germ cells.

Heat shock proteins on the human sperm surface

The sperm plasma membrane is known to be critical to fertilization and to be highly regionalized into domains of head, mid- and principal pieces. However, the molecular composition of the sperm plasma membrane and its alterations during genital tract passage, capacitation and the acrosome reaction remains to be fully dissected. A two-dimensional gel-based proteomic study previously identified 98 human sperm proteins which were accessible for surface labelling with both biotin and radioiodine. In this report twelve dually labelled protein spots were excised from stained gels or PDVF membranes and analysed by mass spectrometry (MS) and Edman degradation. Seven members from four different heat shock protein (HSP) families were identified including HYOU1 (ORP150), HSPC1 (HSP86), HSPA5 (Bip), HSPD1 (HSP60), and several isoforms of the two testis-specific HSP70 chaperones HSPA2 and HSPA1L. An antiserum raised against the testis-specific HSPA2 chaperone reacted with three 65kDa HSPA2 isoforms and three high molecular weight surface proteins (78-79kDa, 84kDa and 90-93kDa). These proteins, together with seven 65kDa HSP70 forms, reacted with human anti-sperm IgG antibodies that blocked in vitro fertilization in humans. Three of these surface biotinylated human sperm antigens were immunoprecipitated with a rabbit antiserum raised against a linear peptide epitope in Chlamydia trachomatis HSP70. The results indicate diverse HSP chaperones are accessible for surface labelling on human sperm. Some of these share epitopes with C. trachomatis HSP70, suggesting an association between genital tract infection, immunity to HSP70 and reproductive failure.

Genetic and developmental basis for urinary tract obstruction

Urinary tract obstruction results in obstructive nephropathy and uropathy. It is the most frequent cause of renal failure in infants and children. In the past two decades studies of transgenic models and humans have greatly enhanced our understanding of the genetic factors and developmental processes important in urinary tract obstruction. The emerging picture is that development of the urinary tract requires precise integration of a variety of progenitor cell populations of different embryonic origins. Such integration is controlled by an intricate signaling network that undergoes dynamic changes as the embryo develops. Most congenital forms of urinary tract obstruction result from the disruption of diverse factors and genetic pathways involved in these processes, especially in the morphogenesis of the urinary conduit or the functional aspects of the pyeloureteral peristaltic machinery.