Roles of heat shock factors in gametogenesis and development

Y2O3NPs induce selective cytotoxicity, genomic instability, oxidative stress and ROS mediated mitochondrial apoptosis in human epidermoid skin A-431 Cancer cells

Yttrium oxide nanoparticles (Y2O3NPs) have emerged as a promising avenue for cancer therapy, primarily due to their distinctive properties that facilitate selective targeting of cancer cells. Despite their potential, the therapeutic effects of Y2O3NPs on human epidermoid skin cancer remain largely unexplored. This study was thus conducted to investigate the impact of Y2O3NPs on both human skin normal and cancer cells, with an emphasis on assessing their cytotoxicity, genotoxicity, and the mechanisms underlying these effects. Cell viability and apoptosis induction were assessed using the Sulforhodamine B and chromatin diffusion assay, respectively. Reactive oxygen species (ROS) level, mitochondrial membrane potential integrity, oxidative stress markers and expression level of apoptotic and mitochondrial genes were also estimated. Our findings highlight the selective and significant cytotoxicity of Y2O3NPs against human epidermoid A-431 cancer cells. Notably, exposure to five Y2O3NPs concentrations (0.1, 1, 10, 100 and 1000 µg/ml) resulted in a high concentration-dependent reduction in cell viability and a corresponding increase in cell death observed 72 h post-treatment specifically in A-431 cancer cells, while normal skin fibroblast (HSF) cells exhibited minimal toxicity. When A-431 cancer cells were treated with the half-maximal inhibitory concentration (IC50) of Y2O3NPs for 72 h, a significant increase in ROS generation was noted. This led to oxidative stress, along with severe damage to genomic DNA and mitochondrial membrane potential, triggering substantial apoptosis. Furthermore, a concurrent significant upregulation of apoptotic p53 and mitochondrial ND3 genes was observed, coupled with a notable decrease in the anti-apoptotic Bcl2 gene expression.Overall, Y2O3NPs demonstrate considerable promise as a therapeutic agent for skin epidermoid cancer due to their ability to selectively target and induce cytotoxic effects in A-431 cancer cells, all while causing minimal harm to normal HSF cells. This selective cytotoxicity appears to be associated with Y2O3NPs' ability to induce excessive ROS production and subsequent oxidative stress, leading to significant genomic DNA fragmentation, loss of mitochondrial permeability, and alterations in apoptotic and mitochondrial genes' expression, ultimately promoting apoptosis in A-431 cancer cells. These findings establish a foundation for further research into the utilization of Y2O3NPs in targeted cancer therapies and underscore the necessity for ongoing investigation into their safety and efficacy in clinical applications.

Genome-wide analyses of genomic diversity, population structure and selection signatures in Italian turkey populations

Italian local turkey populations are an important source of genetic diversity that should be preserved through an in vivo approach. Whole genome sequencing (WGS) and genotyping datasets were used to assess genetic variability within and across populations, to perform a genome-wide comparative analysis among populations and to identify selection signatures in Italian turkey populations. We used new data from 73 WGS samples (12X) representing five turkey populations, together with previous data from 107 birds genotyped with the Affymetrix 600K single nucleotide polymorphism (SNP) turkey array from 11 populations. The PCA and Admixture show a relatively strong isolation effect between the populations. Moreover, the values of genomic inbreeding based on ROH (FROH) showed marked differences among populations and ranged from 0.096 to 0.643. Selective sweeps were identified using the integrated haplotype score (iHS) within the local group, the commercial line, and the Narragansett breed, resulting in the identification of 20, 19, and 27 regions with a total of 73, 48, and 90 candidate genes, respectively. Some of these genes such as FAM107B, MSTN, PDZRN4, HSF2 and GJA1 are associated with heat stress, growth, and carcass traits. We conclude that our results improve our understanding of the genomic architecture of the Italian turkey populations. The findings of iHS suggest that selection can play a significant role in shaping selection signatures in local turkey populations and could provide a basis for identifying gene mutations that may be beneficial in adaptation to climate change. Our results will be useful in developing and implementing conservation and selection plans for Italian turkey populations.

HSF1/HSP25 system protects mitochondria function from heat stress and assists steroidogenesis in MA-10 Leydig cells

Heat shock response is characterized by the induction of heat shock proteins (HSPs) or molecular chaperones that maintain protein homeostasis. Heat shock transcription factor 1 (HSF1) plays a central role in heat shock response in mammalian cells. To investigate the impact of the heat shock response mechanism on steroidogenesis, we generated MA-10 mouse Leydig tumor cells deficient in HSF1 using CRISPR-Cas9 genome editing. Under heat stress conditions, the levels of StAR protein, but not its mRNA, decreased more in HSF1-knockout cells than in wild-type cells, confirming that HSF1 stabilizes StAR protein. Simultaneously, HSP110, HSP70, and HSP25 were markedly upregulated in a manner dependent on HSF1. Mitochondrial membrane potential (MMP) and ATP synthesis were decreased in HSF1-knockout cells under heat stress conditions, and mitochondrial fragmentation was enhanced. Furthermore, treatment with carbonyl cyanide 3-chlorophenylhydrazone (CCCP), a disruptor of MMP, reduced the levels of StAR protein to a greater extent in HSF1-knockout cells than in wild-type cells, which was associated with decreased MMP and ATP synthesis. Unexpectedly, HSP25 expression was markedly increased in wild-type cells following CCCP treatment. HSP25 knockdown reduces MMP under heat stress conditions and decreases StAR protein levels and progesterone synthesis. HSP25 overexpression in HSF1KO cells restored StAR protein levels. These results show that the HSF1/HSP25 pathway protects mitochondrial function and maintains StAR synthesis.

Proteomic profiling identifies a direct interaction between heat shock transcription factor 2 and the focal adhesion adapter talin-1

Heat shock factor 2 (HSF2) is a versatile transcription factor that regulates gene expression under stress conditions, during development, and in disease. Despite recent advances in characterizing HSF2-dependent target genes, little is known about the protein networks associated with this transcription factor. In this study, we performed co-immunoprecipitation coupled with mass spectrometry analysis to identify the HSF2 interactome in mouse testes, where HSF2 is required for normal sperm development. Endogenous HSF2 was discovered to form a complex with several adhesion-associated proteins, a finding substantiated by mass spectrometry analysis conducted in human prostate carcinoma PC-3 cells. Notably, this group of proteins included the focal adhesion adapter protein talin-1 (TLN1). Through co-immunoprecipitation and proximity ligation assays, we demonstrate the conservation of the HSF2-TLN1 interaction from mouse to human. Additionally, employing sequence alignment analyses, we uncovered a TLN1-binding motif in the HSF2 C terminus that binds directly to multiple regions of TLN1 in vitro. We provide evidence that the 25 C-terminal amino acids of HSF2, fused to EGFP, are sufficient to establish a protein complex with TLN1 and modify cell-cell adhesion in human cells. Importantly, this TLN1-binding motif is absent in the C-terminus of a closely related HSF family member, HSF1, which does not form a complex with TLN1. These results highlight the unique molecular characteristics of HSF2 in comparison to HSF1. Taken together, our data unveil the protein partners associated with HSF2 in a physiologically relevant context and identifies TLN1 as the first adhesion-related HSF2-interacting partner.

The Expression and Epigenetic Characteristics of the HSF2 Gene in Cattle-Yak and the Correlation with Its Male Sterility

Aberrant expression of the heat shock proteins and factors was revealed to be closely associated with male reproduction. Heat shock factor 2 (HSF2) is a transcription factor that is involved in the regulation of diverse developmental pathways. However, the role and the corresponding molecular mechanism of HSF2 in male cattle-yak sterility are still poorly understood. Therefore, the aim of this study was to obtain the sequence and the biological information of the cattle-yak HSF2 gene and to investigate the spatiotemporal expression profiles of the locus during the development of cattle-yak testes. Additionally, the differential expression was analyzed between the cattle-yak and the yak, and the methylation of corresponding promoter regions was compared. Our results showed an additional 54 bp fragment and a missense mutation (lysine to glutamic acid) were presented in the cattle-yak HSF2 gene, which correlated with enriched expression in testicular tissue. In addition, the expression of the HSF2 gene showed dynamic changes during the growth of the testes, reaching a peak in adulthood. The IHC indicated that HSF2 protein was primarily located in spermatocytes (PS), spermatogonia (SP), and Sertoli cells (SC) in cattle-yak testes, compared with the corresponding cells of cattle and the yak. Furthermore, bisulfite-sequencing PCR (BSP) revealed that the methylated CpG sites in the promoter region of the cattle-yak HSF2 were more numerous than in the yak counterpart, which suggests hypermethylation of this region in the cattle-yak. Taken together, the low expression abundance and hypermethylation of HSF2 may underpin the obstruction of spermatogenesis, which leads to male cattle-yak infertility. Our study provided a basic guideline for the HSF2 gene in male reproduction and a new insight into the mechanisms of male cattle-yak sterility.

Atypical heat shock transcription factor HSF5 is critical for male meiotic prophase under non-stress conditions

Meiotic prophase progression is differently regulated in males and females. In males, pachytene transition during meiotic prophase is accompanied by robust alteration in gene expression. However, how gene expression is regulated differently to ensure meiotic prophase completion in males remains elusive. Herein, we identify HSF5 as a male germ cell-specific heat shock transcription factor (HSF) for meiotic prophase progression. Genetic analyzes and single-cell RNA-sequencing demonstrate that HSF5 is essential for progression beyond the pachytene stage under non-stress conditions rather than heat stress. Chromatin binding analysis in vivo and DNA-binding assays in vitro suggest that HSF5 binds to promoters in a subset of genes associated with chromatin organization. HSF5 recognizes a DNA motif different from typical heat shock elements recognized by other canonical HSFs. This study suggests that HSF5 is an atypical HSF that is required for the gene expression program for pachytene transition during meiotic prophase in males.

Screening of temperature-responsive signalling molecules during sex differentiation in Asian yellow pond turtle (Mauremys mutica)

BACKGROUND

The Asian yellow pond turtle (Mauremys mutica) is an important commercial freshwater aquaculture species in China. This species is a highly sexually dimorphic species, with males growing at a faster rate than females and exhibits temperature-dependent sex determination (TSD), in which the incubation temperature during embryonic development determines the sexual fate. However, the mechanisms of the sex determination or sex differentiation in the Asian yellow pond turtle are remain a mystery.

RESULTS

Temperature-specific gonadal transcriptomics of the Asian yellow pond turtle were performed during the thermosensitive period (stage 15) using RNA-seq technology to identify candidate genes that initiate gonadal differentiation. We uncovered candidates that were the first to respond to temperature. These candidates were sexually dimorphic in expression, reflecting differences in gonadal (Cirbp, Runx1) and germline differentiation (Vasa, Nanos1, Piwil2), gametogenesis (Hmgb3, Zar1, Ovoinhibitor-like, Kif4), steroid hormone biosynthesis (Hsd17b5, Hsd17b6), heat shock (Dnajb6, Hsp90b1, Hsp90aa1) and transient receptor potential channel genes (Trpm1, Trpm4, Trpm6, Trpv1).

CONCLUSIONS

Our work will provide important genetic information to elucidate the mechanisms of sex control in the Asian yellow pond turtles, and will contribute important genetic resources for further studies of temperature-dependent sex determination in turtles.

An Increase in HSF1 Expression Directs Human Mammary Epithelial Cells toward a Mesenchymal Phenotype

HSF1 is a well-known heat shock protein expression regulator in response to stress. It also regulates processes important for growth, development or tumorigenesis. We studied the HSF1 influence on the phenotype of non-tumorigenic human mammary epithelial (MCF10A and MCF12A) and several triple-negative breast cancer cell lines. MCF10A and MCF12A differ in terms of HSF1 levels, morphology, growth in Matrigel, expression of epithelial (CDH1) and mesenchymal (VIM) markers (MCF10A are epithelial cells; MCF12A resemble mesenchymal cells). HSF1 down-regulation led to a reduced proliferation rate and spheroid formation in Matrigel by MCF10A cells. However, it did not affect MCF12A proliferation but led to CDH1 up-regulation and the formation of better organized spheroids. HSF1 overexpression in MCF10A resulted in reduced CDH1 and increased VIM expression and the acquisition of elongated fibroblast-like morphology. The above-mentioned results suggest that elevated levels of HSF1 may direct mammary epithelial cells toward a mesenchymal phenotype, while a lowering of HSF1 could reverse the mesenchymal phenotype to an epithelial one. Therefore, HSF1 may be involved in the remodeling of mammary gland architecture over the female lifetime. Moreover, HSF1 levels positively correlated with the invasive phenotype of triple-negative breast cancer cells, and their growth was inhibited by the HSF1 inhibitor DTHIB.

Regulation of plant epigenetic memory in response to cold and heat stress: towards climate resilient agriculture

Plants have evolved to adapt and grow in hot and cold climatic conditions. Some also adapt to daily and seasonal temperature changes. Epigenetic modifications play an important role in regulating plant tolerance under such conditions. DNA methylation and post-translational modifications of histone proteins influence gene expression during plant developmental stages and under stress conditions, including cold and heat stress. While short-term modifications are common, some modifications may persist and result in stress memory that can be inherited by subsequent generations. Understanding the mechanisms of epigenomes responding to stress and the factors that trigger stress memory is crucial for developing climate-resilient agriculture, but such an integrated view is currently limited. This review focuses on the plant epigenetic stress memory during cold and heat stress. It also discusses the potential of machine learning to modify stress memory through epigenetics to develop climate-resilient crops.

S. M, Birudala G, Jamous YF, Alshargi O, Kotha KK, Sudhan HH, Mani RR, Muthumanickam A, Niranjan D, Jain NK, Agrawal A, Jadon AS, Mayasa V, Jha NK, Kolesarova A, Slama P, Roychoudhury S. Reactive oxygen species mediated apoptotic death of colon cancer cells: therapeutic potential of plant derived alkaloids

Colorectal cancer (CRC) is one of the most deaths causing diseases worldwide. Several risk factors including hormones like insulin and insulin like growth factors (e.g., IGF-1) have been considered responsible for growth and progression of colon cancer. Though there is a huge advancement in the available screening as well as treatment techniques for CRC. There is no significant decrease in the mortality of cancer patients. Moreover, the current treatment approaches for CRC are associated with serious challenges like drug resistance and cancer re-growth. Given the severity of the disease, there is an urgent need for novel therapeutic agents with ideal characteristics. Several pieces of evidence suggested that natural products, specifically medicinal plants, and derived phytochemicals may serve as potential sources for novel drug discovery for various diseases including cancer. On the other hand, cancer cells like colon cancer require a high basal level of reactive oxygen species (ROS) to maintain its own cellular functions. However, excess production of intracellular ROS leads to cancer cell death via disturbing cellular redox homeostasis. Therefore, medicinal plants and derived phytocompounds that can enhance the intracellular ROS and induce apoptotic cell death in cancer cells via modulating various molecular targets including IGF-1 could be potential therapeutic agents. Alkaloids form a major class of such phytoconstituents that can play a key role in cancer prevention. Moreover, several preclinical and clinical studies have also evidenced that these compounds show potent anti-colon cancer effects and exhibit negligible toxicity towards the normal cells. Hence, the present evidence-based study aimed to provide an update on various alkaloids that have been reported to induce ROS-mediated apoptosis in colon cancer cells via targeting various cellular components including hormones and growth factors, which play a role in metastasis, angiogenesis, proliferation, and invasion. This study also provides an individual account on each such alkaloid that underwent clinical trials either alone or in combination with other clinical drugs. In addition, various classes of phytochemicals that induce ROS-mediated cell death in different kinds of cancers including colon cancer are discussed.

miRNA expression profiles of peripheral white blood cells from beef heifers with varying reproductive potential

Reproductive performance is the most critical factor affecting production efficiency in the cow-calf industry. Heifers with low reproductive efficiency may fail to become pregnant during the breeding season or maintain a pregnancy. The cause of reproductive failure often remains unknown, and the non-pregnant heifers are not identified until several weeks after the breeding season. Therefore, improving heifer fertility utilizing genomic information has become increasingly important. One approach is using microRNAs (miRNA) in the maternal blood that play an important role in regulating the target genes underlying pregnancy success and thereby in selecting reproductively efficient heifers. Therefore, the current study hypothesized that miRNA expression profiles from peripheral white blood cells (PWBC) at weaning could predict the future reproductive outcome of beef heifers. To this end, we measured the miRNA profiles using small RNA-sequencing in Angus-Simmental crossbred heifers sampled at weaning and retrospectively classified as fertile (FH, n = 7) or subfertile (SFH, n = 7). In addition to differentially expressed miRNAs (DEMIs), their target genes were predicted from TargetScan. The PWBC gene expression from the same heifers were retrieved and co-expression networks were constructed between DEMIs and their target genes. We identified 16 differentially expressed miRNAs between the groups (p-value ≤0.05 and absolute (log2 fold change ≥0.05)). Interestingly, based on a strong negative correlation identified from miRNA-gene network analysis with PCIT (partial correlation and information theory), we identified miRNA-target genes in the SFH group. Additionally, TargetScan predictions and differential expression analysis identified bta-miR-1839 with ESR1 , bta-miR-92b with KLF4 and KAT2B, bta-miR-2419-5p with LILRA4, bta-miR-1260b with UBE2E1, SKAP2 and CLEC4D, and bta-let-7a-5p with GATM, MXD1 as miRNA-gene targets. The miRNA-target gene pairs in the FH group are over-represented for MAPK, ErbB, HIF-1, FoxO, p53, mTOR, T-cell receptor, insulin and GnRH signaling pathways, while those in the SFH group include cell cycle, p53 signaling pathway and apoptosis. Some miRNAs, miRNA-target genes and regulated pathways identified in this study have a potential role in fertility; other targets are identified as novel and need to be validated in a bigger cohort that could help to predict the future reproductive outcomes of beef heifers.

Regulation of germline proteostasis by HSF1 and insulin/IGF-1 signaling

Protein homeostasis (proteostasis) is essential for cellular function and organismal health and requires the concerted actions of protein synthesis, folding, transport, and turnover. In sexually reproducing organisms, the immortal germline lineage passes genetic information across generations. Accumulating evidence indicates the importance of proteome integrity for germ cells as genome stability. As gametogenesis involves very active protein synthesis and is highly energy-demanding, it has unique requirements for proteostasis regulation and is sensitive to stress and nutrient availability. The heat shock factor 1 (HSF1), a key transcriptional regulator of cellular response to cytosolic and nuclear protein misfolding has evolutionarily conserved roles in germline development. Similarly, insulin/insulin-like growth factor-1 (IGF-1) signaling, a major nutrient-sensing pathway, impacts many aspects of gametogenesis. Here, we focus on HSF1 and IIS to review insights into their roles in germline proteostasis and discuss the implications on gamete quality control during stress and aging.

Organismal Roles of Hsp90

Heat shock protein 90 (Hsp90) is a highly conserved molecular chaperone that assists in the maturation of many client proteins involved in cellular signal transduction. As a regulator of cellular signaling processes, it is vital for the maintenance of cellular proteostasis and adaptation to environmental stresses. Emerging research shows that Hsp90 function in an organism goes well beyond intracellular proteostasis. In metazoans, Hsp90, as an environmentally responsive chaperone, is involved in inter-tissue stress signaling responses that coordinate and safeguard cell nonautonomous proteostasis and organismal health. In this way, Hsp90 has the capacity to influence evolution and aging, and effect behavioral responses to facilitate tissue-defense systems that ensure organismal survival. In this review, I summarize the literature on the organismal roles of Hsp90 uncovered in multicellular organisms, from plants to invertebrates and mammals.

Seasonal variation in the morphokinetics of in-vitro-derived bovine embryos is associated with the blastocyst developmental competence and gene expression

Summer heat stress is a major cause of reduced development of preimplantation embryos. Nevertheless, seasonal effects on embryo morphokinetics have been less studied. We used a non-invasive time-lapse system that allows continuous monitoring of embryos to study the seasonal impact on embryo morphokinetics. The experiments were performed during the cold and the hot seasons. Cumulus-oocyte complexes were aspirated from ovaries, in-vitro-matured, and fertilized. Putative zygotes were cultured in an incubator equipped with a time-lapse system. The cleavage and blastocyst formation rates were lower in the hot vs. the cold season (p < 0.01). The kinetics of the embryos differed between seasons, reflected by a delay in the second cleavage in the hot vs. the cold season (p < 0.03). The distribution of the embryos into different morphological grades (good, fair, and poor) throughout the first three cleavages differed between seasons, with a higher proportion of good-grade embryos in the hot season (p < 0.03). Cleaved embryos were categorized as either normal or abnormal, based on their first cleavage pattern. Normal cleavage was defined as when the first cleavage resulted in two equal blastomeres and further classified as either synchronous or asynchronous, according to their subsequent cleavages. Abnormal cleavage was defined as when the embryo directly cleaved into more than two blastomeres, it cleaved unequally into two unevenly sized blastomeres, or when the fusion of already divided blastomeres occurred. The proportion of abnormally cleaved embryos was higher in the hot season vs. the cold one (p < 0.01), reflected by a higher proportion of unequally cleaved embryos (p < 0.02). In the cold season, abnormally cleaved embryos had a lower potential to develop into blastocysts relative to their normally cleaved counterparts (p < 0.001). Blastocysts that developed in the cold and the hot seasons differed in the expression of genes that related to the cell cycle (STAT1; p < 0.01), stress (HSF1; p < 0.03), and embryo development (ZP3; p < 0.05). A higher expression level was recorded for the STAT1 and UHRF1 genes in blastocysts that developed from unequally vs. the synchronously cleaved embryos (p < 0.04). We provide the first evidence for a seasonal effect on embryo morphokinetics, which might explain the reduced embryo development during the hot season.

The exploration of miRNAs and mRNA profiles revealed the molecular mechanisms of cattle-yak male infertility

Cattle-yak, the first-generation offspring of cattle and yak, inherited many excellent characteristics from their parents. However, F1 male hybrid infertility restricts the utilization of heterosis greatly. In this study, we first compared the testicular tissue histological characteristics of three cattle, three yaks, and three cattle-yak. Then we explored the miRNA profiles and the target functions of nine samples with RNA-seq technology. We further analyzed the function of DE gene sets of mRNA profiles identified previously with GSEA. Testicular histology indicated that the seminiferous tubules became vacuolated and few active germ cells can be seen. RNA-seq results showed 47 up-regulated and 34 down-regulated, 16 up-regulated and 21 down-regulated miRNAs in cattle and yaks compared with cattle-yak, respectively. From the intersection of DE miRNAs, we identified that bta-miR-7 in cattle-yak is down-regulated. Target prediction indicated that the filtered genes especially MYRFL, FANCA, INSL3, USP9X, and SHF of bta-miR-7 may play crucial roles in the reproductive process. With further network analysis and GSEA, we screened such hub genes and function terms, we also found some DE gene sets that enriched in ATP binding, DNA binding, and reproduction processes. We concluded that bta-miR-7 may play an important role in influencing fecundity. Our study provides new insights for explaining the molecular mechanism of cattle-yak infertility.

Arabidopsis HEAT SHOCK FACTOR BINDING PROTEIN is required to limit meiotic crossovers and HEI10 transcription

The number of meiotic crossovers is tightly controlled and most depend on pro-crossover ZMM proteins, such as the E3 ligase HEI10. Despite the importance of HEI10 dosage for crossover formation, how HEI10 transcription is controlled remains unexplored. In a forward genetic screen using a fluorescent crossover reporter in Arabidopsis thaliana, we identify heat shock factor binding protein (HSBP) as a repressor of HEI10 transcription and crossover numbers. Using genome-wide crossover mapping and cytogenetics, we show that hsbp mutations or meiotic HSBP knockdowns increase ZMM-dependent crossovers toward the telomeres, mirroring the effects of HEI10 overexpression. Through RNA sequencing, DNA methylome, and chromatin immunoprecipitation analysis, we reveal that HSBP is required to repress HEI10 transcription by binding with heat shock factors (HSFs) at the HEI10 promoter and maintaining DNA methylation over the HEI10 5' untranslated region. Our findings provide insights into how the temperature response regulator HSBP restricts meiotic HEI10 transcription and crossover number by attenuating HSF activity.

Protecting the future: balancing proteostasis for reproduction

The proteostasis network (PN) regulates protein synthesis, folding, and degradation and is critical for the health and function of all cells. The PN has been extensively studied in the context of aging and age-related diseases, and loss of proteostasis is regarded as a major contributor to many age-associated disorders. In contrast to somatic tissues, an important feature of germ cells is their ability to maintain a healthy proteome across generations. Accumulating evidence has now revealed multiple layers of PN regulation that support germ cell function, determine reproductive capacity during aging, and prioritize reproduction at the expense of somatic health. Here, we review recent insights into these different modes of regulation and their implications for reproductive and somatic aging.

FGD3 binds with HSF4 to suppress p65 expression and inhibit pancreatic cancer progression

Pancreatic cancer is regarded as the most lethal solid tumor worldwide. Deregulated and constitutively activated NF-κB signaling is one of the major characteristics of pancreatic cancer. The total expression level and subcellular localization of RelA/p65 have been shown to determine the activation of canonical NF-κB signaling in pancreatic cancer. FGD3, which is involved in regulating the actin cytoskeleton and cell shape, has been reported to inhibit cancer cell migration and predict a favorable prognosis in multiple types of cancer. However, the specific role of FGD3 in pancreatic cancer is still unknown. In this study, we conducted a systematic investigation of the cancer-related role of FGD3 in pancreatic cancer. We demonstrated that FGD3 was abnormally downregulated in pancreatic cancer tissues and that low expression of FGD3 was associated with unfavorable prognosis in patients with pancreatic cancer. Then, we showed that FGD3 inhibited pancreatic cancer cell proliferation, invasion and metastasis in vivo and in vitro. Moreover, we revealed that FGD3 silencing activated the NF-κB signaling pathway by promoting HSF4 nuclear translocation and increasing p65 expression in pancreatic cancer cells. Therefore, our results identified a novel and targetable FGD3/HSF4/p65 signaling axis in pancreatic cancer cells.

Stress Responses as Master Keys to Epigenomic Changes in Transcriptome and Metabolome for Cancer Etiology and Therapeutics

From initiation through progression, cancer cells are subjected to a magnitude of endogenous and exogenous stresses, which aid in their neoplastic transformation. Exposure to these classes of stress induces imbalance in cellular homeostasis and, in response, cancer cells employ informative adaptive mechanisms to rebalance biochemical processes that facilitate survival and maintain their existence. Different kinds of stress stimuli trigger epigenetic alterations in cancer cells, which leads to changes in their transcriptome and metabolome, ultimately resulting in suppression of growth inhibition or induction of apoptosis. Whether cancer cells show a protective response to stress or succumb to cell death depends on the type of stress and duration of exposure. A thorough understanding of epigenetic and molecular architecture of cancer cell stress response pathways can unveil a plethora of information required to develop novel anticancer therapeutics. The present view highlights current knowledge about alterations in epigenome and transcriptome of cancer cells as a consequence of exposure to different physicochemical stressful stimuli such as reactive oxygen species (ROS), hypoxia, radiation, hyperthermia, genotoxic agents, and nutrient deprivation. Currently, an anticancer treatment scenario involving the imposition of stress to target cancer cells is gaining traction to augment or even replace conventional therapeutic regimens. Therefore, a comprehensive understanding of stress response pathways is crucial for devising and implementing novel therapeutic strategies.

Heat Shock Factors in Protein Quality Control and Spermatogenesis

Proper regulation of cellular protein quality control is crucial for cellular health. It appears that the protein quality control machinery is subjected to distinct regulation in different cellular contexts such as in somatic cells and in germ cells. Heat shock factors (HSFs) play critical role in the control of quality of cellular proteins through controlling expression of many genes encoding different proteins including those for inducible protein chaperones. Mammalian cells exert distinct mechanism of cellular functions through maintenance of tissue-specific HSFs. Here, we have discussed different HSFs and their functions including those during spermatogenesis. We have also discussed the different heat shock proteins induced by the HSFs and their activities in those contexts. We have also identified several small molecule activators and inhibitors of HSFs from different sources reported so far.

Insulin/IGF-1 signaling and heat stress differentially regulate HSF1 activities in germline development

Germline development is sensitive to nutrient availability and environmental perturbation. Heat shock transcription factor 1 (HSF1), a key transcription factor driving the cellular heat shock response (HSR), is also involved in gametogenesis. The precise function of HSF1 (HSF-1 in C. elegans) and its regulation in germline development are poorly understood. Using the auxin-inducible degron system in C. elegans, we uncovered a role of HSF-1 in progenitor cell proliferation and early meiosis and identified a compact but important transcriptional program of HSF-1 in germline development. Interestingly, heat stress only induces the canonical HSR in a subset of germ cells but impairs HSF-1 binding at its developmental targets. Conversely, insulin/insulin growth factor 1 (IGF-1) signaling dictates the requirement for HSF-1 in germline development and functions through repressing FOXO/DAF-16 in the soma to activate HSF-1 in germ cells. We propose that this non-cell-autonomous mechanism couples nutrient-sensing insulin/IGF-1 signaling to HSF-1 activation to support homeostasis in rapid germline growth.

Role of heat shock transcription factor 2 in the NMDA-dependent neuroplasticity induced by chronic ethanol intake in mouse hippocampus

Ethanol consumption impairs learning and memory through disturbances of NMDA-type glutamate receptor-dependent synaptic plasticity (long-term depression [LTD] and long-term potentiation [LTP]) in the hippocampus. Recently, we demonstrated that two ethanol binge-like episodes in young adult rats selectively blocked NMDA-LTD in hippocampal slices, increased NMDA receptor sensitivity to a GluN2B subunit antagonist, and induced cognitive deficits. Here, using knockout adult mice, we show that a stress-responsive transcription factor of the heat shock factor family, HSF2, which is involved in the perturbation of brain development induced by ethanol, participates in these processes. In the absence of ethanol, hsf2^-/- mice show a selective loss of LTD in the hippocampus, which is associated with an increased sensitivity of NMDA-field excitatory postsynaptic potentials (fEPSPs) to a GluN2B antagonist, compared with wild-type (WT) mice. These results suggest that HSF2 is required for proper glutamatergic synaptic transmission and LTD plasticity. After 1 month of chronic ethanol consumption in a two-bottle choice paradigm, WT mice showed an increase in hippocampal synaptic transmission, an enhanced sensitivity to GluN2B antagonist, and a blockade of LTD. In contrast, such modulation of synaptic transmission and plasticity were absent in hsf2^-/- mice. We conclude that HSF2 is an important mediator of both glutamatergic neurotransmission and synaptic plasticity in basal conditions and also mediates ethanol-induced neuroadaptations of the hippocampus network after chronic ethanol intake.

The proteostasis guardian HSF1 directs the transcription of its paralog and interactor HSF2 during proteasome dysfunction

Protein homeostasis is essential for life in eukaryotes. Organisms respond to proteotoxic stress by activating heat shock transcription factors (HSFs), which play important roles in cytoprotection, longevity and development. Of six human HSFs, HSF1 acts as a proteostasis guardian regulating stress-induced transcriptional responses, whereas HSF2 has a critical role in development, in particular of brain and reproductive organs. Unlike HSF1, that is a stable protein constitutively expressed, HSF2 is a labile protein and its expression varies in different tissues; however, the mechanisms regulating HSF2 expression remain poorly understood. Herein we demonstrate that the proteasome inhibitor anticancer drug bortezomib (Velcade), at clinically relevant concentrations, triggers de novo HSF2 mRNA transcription in different types of cancers via HSF1 activation. Similar results were obtained with next-generation proteasome inhibitors ixazomib and carfilzomib, indicating that induction of HSF2 expression is a general response to proteasome dysfunction. HSF2-promoter analysis, electrophoretic mobility shift assays, and chromatin immunoprecipitation studies unexpectedly revealed that HSF1 is recruited to a heat shock element located at 1.397 bp upstream from the transcription start site in the HSF2-promoter. More importantly, we found that HSF1 is critical for HSF2 gene transcription during proteasome dysfunction, representing an interesting example of transcription factor involved in controlling the expression of members of the same family. Moreover, bortezomib-induced HSF2 was found to localize in the nucleus, interact with HSF1, and participate in bortezomib-mediated control of cancer cell migration. The results shed light on HSF2-expression regulation, revealing a novel level of HSF1/HSF2 interplay that may lead to advances in pharmacological modulation of these fundamental transcription factors.

Male hybrid sterility in the cattle-yak and other bovines: a review

Hybridization is important for both animal breeders attempting to fix new phenotypic traits and researchers trying to unravel the mechanism of reproductive barriers in hybrid species and the process of speciation. In interspecies animal hybrids, gains made in terms of adaptation to environmental conditions and hybrid vigor may be offset by reduced fertility or sterility. Bovine hybrids exhibit remarkable hybrid vigor compared to their parents. However, the F1 male hybrid exhibits sterility, whereas the female is fertile. This male-biased sterility is consistent with the Haldane rule where heterogametic sex is preferentially rare, absent, or sterile in the progeny of two different species. The obstacle of fixing favorable traits and passing them to subsequent generations due to the male sterility is a major setback in improving the reproductive potential of bovines through hybridization. Multiperspective approaches such as molecular genetics, proteomics, transcriptomics, physiology, and endocrinology have been used by several researchers over the past decade in an attempt to unravel the potential mechanisms underlying male hybrid sterility. However, the mechanism of sterility in the hybrid male is still not completely unravelled. This review seeks to provide an update of the mechanisms of the sterility in the cattle-yak and other bovines.

Molecular Mechanisms of Heat Shock Factors in Cancer

Malignant transformation is accompanied by alterations in the key cellular pathways that regulate development, metabolism, proliferation and motility as well as stress resilience. The members of the transcription factor family, called heat shock factors (HSFs), have been shown to play important roles in all of these biological processes, and in the past decade it has become evident that their activities are rewired during tumorigenesis. This review focuses on the expression patterns and functions of HSF1, HSF2, and HSF4 in specific cancer types, highlighting the mechanisms by which the regulatory functions of these transcription factors are modulated. Recently developed therapeutic approaches that target HSFs are also discussed.

The "HSF connection": Pleiotropic regulation and activities of Heat Shock Factors shape pathophysiological brain development

The Heat Shock Factors (HSFs) have been historically identified as a family of transcription factors that are activated and work in a stress-responsive manner, after exposure to a large variety of stimuli. However, they are also critical in normal conditions, in a life long manner, in a number of physiological processes that encompass gametogenesis, embryonic development and the integrity of adult organs and organisms. The importance of such roles is emphasized by the devastating impact of their deregulation on health, ranging from reproductive failure, neurodevelopmental disorders, cancer, and aging pathologies, including neurodegenerative disorders. Here, we provide an overview of the delicate choreography of the regulation of HSFs during neurodevelopment, at prenatal and postnatal stages. The regulation of HSFs acts at multiple layers and steps, and comprises the control of (i) HSF mRNA and protein levels, (ii) HSF activity in terms of DNA-binding and transcription, (iii) HSF homo- and hetero-oligomerization capacities, and (iv) HSF combinatory set of post-translational modifications. We also describe how these regulatory mechanisms operate in the normal developing brain and how their perturbation impact neurodevelopment under prenatal or perinatal stress conditions. In addition, we put into perspective the possible role of HSFs in the evolution of the vertebrate brains and the importance of the HSF pathway in a large variety of neurodevelopmental disorders.

Heat shock factor 5 is essential for spermatogenesis in mice: Detected by a new monoclonal antibody

OBJECTIVES

Here, we examined the function of our produced monoclonal antibody (mAb10C3) to recognize one of the most important members of the HEAT shock factor family, Hsf5, in embryonic development and in spermatogenic cells of adult mouse testis.

MATERIALS AND METHODS

The targeting effects of mAb10C3 were investigated by immunohistochemistry analysis in the different phases of the embryo and in the adult testis tissue sections.

RESULTS

The results of immunohistochemistry staining on the mouse embryos by the supernatant of hybridoma clone that produced mAb10C3, in the early and late phases (E7.5 and E14.5) of embryonic development, indicated that mAb10C3 could only detect Hsf5 in E7.5 and it did not have any targeting activity in the late phase of development. Therefore, we showed that the hsf5 gene has expressed in early mouse embryonic development. On the other hand, mAb10C3 could detect Hsf5 in spermatogonia and spermatocytes of adult testis in comparison with a known anti-Hsf5 antibody (ab98939) and an anti-PCNA antibody as a marker of spermatogonia cells.

CONCLUSION

Taken together, these data indicated that generated anti-testis mAb10C3 was generated against anti-testis proteins, specifically to target Hsf5, and can be useful as a scientific tool to investigate the critical genes in the development and spermatogenesis.

Heat Shock Factor 5 Is Essential for Spermatogenesis in Zebrafish

Heat shock factors (Hsfs) are transcription factors that regulate responses to heat shock and other environmental stimuli. Four heat shock factors (Hsf1-4) have been characterized from vertebrates to date. In addition to stress response, they also play important roles in development and gametogenesis. Here, we study the fifth member of heat shock factor family, Hsf5, using zebrafish as a model organism. Mutant hsf5^-/- males, generated by CRISPR/Cas9 technique, were infertile with drastically reduced sperm count, increased sperm head size, and abnormal tail architecture, whereas females remained fertile. We show that Hsf5 is required for progression through meiotic prophase 1 during spermatogenesis as suggested by the accumulation of cells in the leptotene and zygotene-pachytene stages and increased apoptosis in post-meiotic cells. hsf5^-/- mutants show gonadal misregulation of a substantial number of genes with roles in cell cycle, apoptosis, protein modifications, and signal transduction, indicating an important role of Hsf5 in early stages of spermatogenesis.

Expression of heat shock factor 1, heat shock protein 90 and associated signaling proteins in pregnant rat myometrium: Implications for myometrial proliferation

During pregnancy and labour the myometrium undergoes structural and physiological adaptations as part of a program of development. Heat shock factor 1 (HSF1) is a master regulator of both stress and developmental processes. A noted HSF1-induced gene is the 90 kDa heat shock protein (HSP90), which acts as a chaperone and regulator of cellular processes. Immunoblot analysis demonstrated HSF1 expression levels in pregnant rat myometrium on gestational day (d) 6 were maintained at a significantly higher level compared with d12 to post-partum (PP) time points (P < 0.05), while expression on d12 was significantly higher compared to d15 and d19. The transcriptionally active form pSer230-HSF1 was detected at a significantly greater level at d6 compared with d21 and d23 time points and also at d12 compared with d21, d22 and 23 (labour). Similarly, phosphorylated (P)-HSP90AA1 protein detection was significantly greater on d6 compared to d19 to d23 time points and on d12 compared with d15 to PP time points. In contrast, P-HSP90AB1 showed significantly greater detection levels on d12 compared with d15 while levels on d22 were significantly higher compared to d15, d17 and d19. Immunofluorescence analysis demonstrated that total HSF1 and HSP90 were localized mainly in the cytoplasm of myometrial cells with some detection of HSF1 in nuclei. This work advances our scientific knowledge of the myometrium during pregnancy and the expression profiles of HSF1 and HSP90 within the proliferative phase of myometrial programming suggests a role for them in this period of hyperplasia and myometrial adaptation.

HSB-1 Inhibition and HSF-1 Overexpression Trigger Overlapping Transcriptional Changes To Promote Longevity in Caenorhabditis elegans

Heat shock factor 1 (HSF-1) is a component of the heat shock response pathway that is induced by cytoplasmic proteotoxic stress. In addition to its role in stress response, HSF-1 also acts as a key regulator of the rate of organismal aging. Overexpression of HSF-1 promotes longevity in C. elegans via mechanisms that remain less understood. Moreover, genetic ablation of a negative regulator of HSF-1, termed as heat shock factor binding protein 1 (HSB-1), results in hsf-1-dependent life span extension in animals. Here we show that in the absence of HSB-1, HSF-1 acquires increased DNA binding activity to its genomic target sequence. Using RNA-Seq to compare the gene expression profiles of the hsb-1 mutant and hsf-1 overexpression strains, we found that while more than 1,500 transcripts show ≥1.5-fold upregulation due to HSF-1 overexpression, HSB-1 inhibition alters the expression of less than 500 genes in C. elegans. Roughly half of the differentially regulated transcripts in the hsb-1 mutant have altered expression also in hsf-1 overexpressing animals, with a strongly correlated fold-expression pattern between the two strains. In addition, genes that are upregulated via both HSB-1 inhibition and HSF-1 overexpression include numerous DAF-16 targets that have known functions in longevity regulation. This study identifies how HSB-1 acts as a specific regulator of the transactivation potential of HSF-1 in non-stressed conditions, thus providing a detailed understanding of the role of HSB-1/HSF-1 signaling pathway in transcriptional regulation and longevity in C. elegans.

Roles of Figla/figla in Juvenile Ovary Development and Follicle Formation During Zebrafish Gonadogenesis

Sex determination and differentiation are complex processes. As a juvenile hermaphrodite or undifferentiated gonochorist, zebrafish undergo a special juvenile ovarian phase during sex differentiation, making it an excellent model for studying early oogenesis and folliculogenesis. We provide lines of evidence at morphological, molecular, and genetic levels for roles of factor in the germline α (Figla), an oocyte-specific transcription factor, in early zebrafish gonadogenesis. As in mammals, Figla/figla was also expressed in the gonads and its expression in the ovary was also restricted to early oocytes. Disruption of figla gene by CRISPR/Cas9 led to an all-male phenotype in the mutant. Detailed analysis of early gonadal development showed that the germ cells in the mutant were clustered in cysts and underwent meiosis, forming oocytes at prefollicular chromatin nucleolar (CN) stage (stage IA). However, the subsequent transition from cystic CN oocytes to individual follicular perinucleolar oocytes (stage IB) was blocked, resulting in an all-male phenotype in the mutant. The phenotype of figla mutant could not be rescued by estrogen treatment, in contrast to cyp19a1a mutant, and introduction of tp53 mutation also had no effect, unlike in fancd1 and fancl mutants. Transcriptome analysis revealed that many biological processes and pathways related to germ cell development, especially oogenesis, were upregulated in the presence of Figla and that the regulation of figla expression may involve heat shock proteins. Our results strongly suggest important roles for Figla in juvenile ovary development, especially the formation of individual follicles from cystic oocytes.

Regulation by Hsp27/P53 in testis development and sperm apoptosis of male cattle (cattle-yak and yak)

Heat shock protein 27 (Hsp27)/protein 53 (P53) plays an important role in testis development and spermatozoa regulation, but the relationship between Hsp27/P53 and infertility in cattle is unclear. Here, we focus on male cattle-yak and yak to investigate the expression and localization of Hsp27/P53 in testis tissues and to explore the influence of Hsp27/P53 on infertility. In our study, a total of 54 cattle (24 cattle-yak and 30 yak) were examined. The Hsp27 and P53 messenger RNA (mRNA) of cattle-yak were cloned, and amino acid variations in Hsp27 and P53 were found; the variations led to differences in the protein spatial structure compared with yak. We used real-time quantitative polymerase chain reaction and western blot to investigate whether the expression of Hsp27/P53 mRNA and protein was different in cattle-yak and yak. We found that the expression levels of Hsp27/P53 mRNA and protein were different in the testis developmental stages and the highest expression was observed in testicles during adulthood. Moreover, the Hsp27 expression was significantly higher in yak, whereas P53 expression was higher in cattle-yak (p < 0.01). On this basis, we detected the location of Hsp27/P53 in the testis by immunohistochemistry and immunofluorescence. The results demonstrated that Hsp27 was located in spermatogenic cells at different developmental stages and mesenchymal cells of the yak testicles. However, P53 was located in the primary spermatocyte and interstitial cells of the cattle-yak testicles. In summary, our study proved that the expression of Hsp27/P53 differed across the testis developmental stages and the expression of P53 was higher in the testis of cattle-yak, which suggested that the infertility of cattle-yak may be caused by the upregulation of P53.

Alcohol exposure promotes DNA methyltransferase DNMT3A upregulation through reactive oxygen species-dependent mechanisms

Abundant evidence has accumulated showing that fetal alcohol exposure broadly modifies DNA methylation profiles in the brain. DNA methyltransferases (DNMTs), the enzymes responsible for DNA methylation, are likely implicated in this process. However, their regulation by ethanol exposure has been poorly addressed. Here, we show that alcohol exposure modulates DNMT protein levels through multiple mechanisms. Using a neural precursor cell line and primary mouse embryonic fibroblasts (MEFs), we found that ethanol exposure augments the levels of Dnmt3a, Dnmt3b, and Dnmt3l transcripts. We also unveil similar elevation of mRNA levels for other epigenetic actors upon ethanol exposure, among which the induction of lysine demethylase Kdm6a shows heat shock factor dependency. Furthermore, we show that ethanol exposure leads to specific increase in DNMT3A protein levels. This elevation not only relies on the upregulation of Dnmt3a mRNA but also depends on posttranscriptional mechanisms that are mediated by NADPH oxidase-dependent production of reactive oxygen species (ROS). Altogether, our work underlines complex regulation of epigenetic actors in response to alcohol exposure at both transcriptional and posttranscriptional levels. Notably, the upregulation of DNMT3A emerges as a prominent molecular event triggered by ethanol, driven by the generation of ROS.

The HSF1-PARP13-PARP1 complex facilitates DNA repair and promotes mammary tumorigenesis

Poly(ADP-ribose) polymerase 1 (PARP1) is involved in DNA repair, chromatin structure, and transcription. However, the mechanisms that regulate PARP1 distribution on DNA are poorly understood. Here, we show that heat shock transcription factor 1 (HSF1) recruits PARP1 through the scaffold protein PARP13. In response to DNA damage, activated and auto-poly-ADP-ribosylated PARP1 dissociates from HSF1–PARP13, and redistributes to DNA lesions and DNA damage-inducible gene loci. Histone deacetylase 1 maintains PARP1 in the ternary complex by inactivating PARP1 through deacetylation. Blocking ternary complex formation impairs redistribution of PARP1 during DNA damage, which reduces gene expression and DNA repair. Furthermore, ternary complex formation and PARP1 redistribution protect cells from DNA damage by promoting DNA repair, and support growth of BRCA1-null mammary tumors, which are sensitive to PARP inhibitors. Our findings identify HSF1 as a regulator of genome integrity and define this function as a guarding mechanism for a specific type of mammary tumorigenesis.

PARP1 recruitment to DNA lesions is critical for DNA damage repair but how DNA damage induces PARP1 redistribution is largely unknown. Here, the authors provide evidence that PARP1 redistribution and DNA repair in tumor cells depend on the formation of a HSF1–PARP13–PARP1 complex.

Comparing the dopaminergic neurotoxic effects of benzylpiperazine and benzoylpiperazine

Benzylpiperazine has been designated as Schedule I substance under the Controlled Substances Act by Drug Enforcement Administration. Benzylpiperazine is a piperazine derivative, elevates both dopamine and serotonin extracellular levels producing stimulatory and hallucinogenic effects, respectively, similar to methylenedioxymethamphetamine (MDMA). However, the comparative neurotoxic effects of Piperazine derivatives (benzylpiperazine and benzoylpiperazine) have not been elucidated. Here, piperazine derivatives (benzylpiperazine and benzoylpiperazine) were synthesized in our lab and the mechanisms of cellular-based neurotoxicity were elucidated in a dopaminergic human neuroblastoma cell line (SH-SY5Y). We evaluated the in vitro effects of benzylpiperazine and benzoylpiperazine on the generation of reactive oxygen species, lipid peroxidation, mitochondrial complex-I activity, catalase activity, superoxide dismutase activity, glutathione content, Bax, caspase-3, Bcl-2 and tyrosine hydroxylase expression. Benzylpiperazine and benzoylpiperazine induced oxidative stress, inhibited mitochondrial functions and stimulated apoptosis. This study provides a germinal assessment of the neurotoxic mechanisms induced by piperazine derivatives that lead to neuronal cell death.

Role of Heat Shock Factor 1 in Conserving Cholesterol Transportation in Leydig Cell Steroidogenesis via Steroidogenic Acute Regulatory Protein

Testicular testosterone synthesis begins with cholesterol transport into mitochondria via steroidogenic acute regulatory (StAR) protein in Leydig cells. Acute heat stress is known to obstruct testicular steroidogenesis by transcriptional repression of StAR. In contrast, chronic heat stress such as cryptorchidism or varicocele generally does not affect testicular steroidogenesis, suggesting that Leydig cells adapt to heat stress and retain their steroid synthesis ability. However, the mechanisms of the stress response in steroid-producing cells are unclear. We examined the relationship between the heat stress response and heat shock factor 1 (HSF1), which protects cells from proteotoxic stress by inducing heat shock protein as a molecular chaperone. The influences of HSF1 deficiency on cholesterol transport by StAR and the expression of steroidogenic enzymes under chronic heat stress were studied in testes of HSF1-knockout (HSF1KO) mice with experimental cryptorchidism. StAR protein in wild-type-cryptorchid mice was transiently decreased after induction of cryptorchidism and then gradually returned to basal levels. In contrast, StAR protein in HSF1KO mice continued to decrease and failed to recover, resulting in impaired serum testosterone. StAR messenger RNA was not decreased with cryptorchidism, indicating that posttranslational modification of StAR, not its transcription, was obstructed in cryptorchidism. Other steroidogenic enzymes, including CYP11A1, 3β-HSD, and CYP17A1, were not decreased. Lipid droplets were increased in the cytosol of HSF1KO-cryptorchid mice, suggesting dysfunctional cholesterol transportation. These findings provide insight into the role of HSF1 in Leydig cell steroidogenesis, suggesting that it maintains cholesterol transport by recovering StAR under chronic heat stress.

Human male infertility and its genetic causes

Background

Infertility affects about 15% of couples who wish to have children and half of these cases are associated with male factors. Genetic causes of azoospermia include chromosomal abnormalities, Y chromosome microdeletions, and specific mutations/deletions of several Y chromosome genes. Many researchers have analyzed genes in the AZF region on the Y chromosome; however, in 2003 the SYCP3 gene on chromosome 12 (12q23) was identified as causing azoospermia by meiotic arrest through a point mutation.

Methods

We mainly describe the SYCP3 and PLK4 genes that we have studied in our laboratory, and add comments on other genes associated with human male infertility.

Results

Up to now, The 17 genes causing male infertility by their mutation have been reported in human.

Conclusions

Infertility caused by nonobstructive azoospermia (NOA) is very important in the field of assisted reproductive technology. Even with the aid of chromosomal analysis, ultrasonography of the testis, and detailed endocrinology, only MD‐TESE can confirm the presence of immature spermatozoa in the testes. We strongly hope that these studies help clinics avoid ineffective MD‐TESE procedures.

HSF1 Relieves Amyloid-β-Induced Cardiomyocytes Apoptosis

Accumulation of amyloid-β in organs results in a series of diseases. Heat shock transcription factor 1 (HSF1) is the master regulator of genes encoding molecular chaperones and attenuates apoptosis induced by multiple factors. However, the role of HSF1 on amyloid-β-induced apoptosis is still unknown. The present study was aimed to explore the function of HSF1 in amyloid-β-induced cardiomyocytes apoptosis. TUNEL assay and flow cytometry analysis were used to detect cell apoptosis. Phalloidin staining was used to detect cytoskeleton injury. Changes in expression levels of proteins involved in apoptosis and endoplasmic reticulum stress were measured by Western blot. In our study, amyloid-β was found to promote apoptosis, impair cytoskeleton, and induce endoplasmic reticulum stress in isolated cardiomyocytes. However, these damaging effects of amyloid-β can be relieved by over-expression of HSF1, and the protective role of HSF1 might be associated with the regulation of HSPs expressions. Results of our study suggest that over-expression of HSF1 might become a promising gene therapeutic for the treatment of heart diseases associated with amyloid-β accumulation.

Regulatory elements and transcriptional control of chicken vasa homologue (CVH) promoter in chicken primordial germ cells

BACKGROUND

Primordial germ cells (PGCs), the precursors of functional gametes, have distinct characteristics and exhibit several unique molecular mechanisms to maintain pluripotency and germness in comparison to somatic cells. They express germ cell-specific RNA binding proteins (RBPs) by modulating tissue-specific cis- and trans-regulatory elements. Studies on gene structures of chicken vasa homologue (CVH), a chicken RNA binding protein, involved in temporal and spatial regulation are thus important not only for understanding the molecular mechanisms that regulate germ cell fate, but also for practical applications of primordial germ cells. However, very limited studies are available on regulatory elements that control germ cell-specific expression in chicken. Therefore, we investigated the intricate regulatory mechanism(s) that governs transcriptional control of CVH.

RESULTS

We constructed green fluorescence protein (GFP) or luciferase reporter vectors containing the various 5' flanking regions of CVH gene. From the 5' deletion and fragmented assays in chicken PGCs, we have identified a CVH promoter that locates at -316 to +275 base pair fragment with the highest luciferase activity. Additionally, we confirmed for the first time that the 5' untranslated region (UTR) containing intron 1 is required for promoter activity of the CVH gene in chicken PGCs. Furthermore, using a transcription factor binding prediction, transcriptome analysis and siRNA-mediated knockdown, we have identified that a set of transcription factors play a role in the PGC-specific CVH gene expression.

CONCLUSIONS

These results demonstrate that cis-elements and transcription factors localizing in the 5' flanking region including the 5' UTR and an intron are important for transcriptional regulation of the CVH gene in chicken PGCs. Finally, this information will contribute to research studies in areas of reproductive biology, constructing of germ cell-specific synthetic promoter for tracing primordial germ cells as well as understanding the transcriptional regulation for maintaining germness in PGCs.

Heat Shock Proteins and Maternal Contribution to Oogenesis and Early Embryogenesis

Early embryos develop from fertilized eggs using materials that are stored during oocyte growth and which can be defined as maternal contribution (molecules, factors, or determinants). Several heat shock proteins (HSPs) and the heat shock transcriptional factor (HSF) are part of the maternal contribution that is critical for successful embryogenesis and reproduction. A maternal role for heat shock-related genes was mainly demonstrated in genetic experimental organisms (e.g., fly, nematode, mouse). Nowadays, an increasing number of "omics" data are produced from a large panel of organisms implementing a catalog of maternal and/or embryonic HSPs and HSFs. However, for most of them, it remains to better understand their potential roles in this context. Existing and future genome-wide screens mainly set up to create loss-of-function are likely to improve this situation. This chapter will discuss available data from various experimental organisms following the developmental steps from egg production to early embryogenesis.

The Role of Heat Shock Factors in Mammalian Spermatogenesis

Heat shock transcription factors (HSFs), as regulators of heat shock proteins (HSPs) expression, are well known for their cytoprotective functions during cellular stress. They also play important yet less recognized roles in gametogenesis. All HSF family members are expressed during mammalian spermatogenesis, mainly in spermatocytes and round spermatids which are characterized by extensive chromatin remodeling. Different HSFs could cooperate to maintain proper spermatogenesis. Cooperation of HSF1 and HSF2 is especially well established since their double knockout results in meiosis arrest, spermatocyte apoptosis, and male infertility. Both factors are also involved in the repackaging of the DNA during spermatid differentiation. They can form heterotrimers regulating the basal level of transcription of target genes. Moreover, HSF1/HSF2 interactions are lost in elevated temperatures which can impair the transcription of genes essential for spermatogenesis. In most mammals, spermatogenesis occurs a few degrees below the body temperature and spermatogenic cells are extremely heat-sensitive. Pro-survival pathways are not induced by heat stress (e.g., cryptorchidism) in meiotic and postmeiotic cells. Instead, male germ cells are actively eliminated by apoptosis, which prevents transition of the potentially damaged genetic material to the next generation. Such a response depends on the transcriptional activity of HSF1 which in contrary to most somatic cells, acts as a proapoptotic factor in spermatogenic cells. HSF1 activation could be the main trigger of impaired spermatogenesis related not only to elevated temperature but also to other stress conditions; therefore, HSF1 has been proposed to be the quality control factor in male germ cells.

Medical morbidities and DNA methylation of NR3C1 in preterm infants

BACKGROUND

Although there are no accepted "normal" levels of circulating cortisol in preterm infants, critically ill preterm infants show lower cortisol levels than healthy preterm infants. The regulation of cortisol reactivity by epigenetic changes in glucocorticoid receptor gene (NR3C1) expression has been demonstrated. This study aims to examine the relationship between medical morbidities in preterm infants and DNA methylation of NR3C1.

METHODS

Pyrosequencing was used to determine DNA methylation in CpG sites 1-4 of promoter region 1F of NR3C1. Cluster analysis placed 67 preterm infants born <1,500 g into groups based on medical morbidities. The DNA methylation pattern was compared across groups.

RESULTS

Cluster analysis identified a high medical risk cluster and a low medical risk cluster. A Mann-Whitney U-test showed lower methylation at CpG1 for infants in the high-risk group (M = 0.336, SE = 0.084) than infants in the low-risk group (M = 0.617, SE = 0.109, P = 0.032). The false discovery rate was low (q = 0.025). Cohen's D effect size was moderate (0.525).

CONCLUSION

Decreased DNA methylation of CpG1 of NR3C1 in high-risk infants may allow for increased binding of transcription factors involved in the stress response, repair and regulation of NR3C1. This may ensure healthy growth in high-risk preterm infants over increasing cortisol levels.

Fluoride exposure changed the structure and the expressions of Y chromosome related genes in testes of mice

It is known that during spermatogenesis, pluripotent germ cells differentiate to become efficient delivery vehicles to the oocyte of paternal DNA, and the process is easily damaged by external poison. In this study, the effects of fluoride on the body weight, fluoride content in femur, testosterone levels in serum and testis, sperm quality, and the expressions of Y chromosome microdeletion genes and protein levels were examined in testes of Kunming male mice treated with different concentrations of 0, 25, 50, 100 mg/L of NaF in drinking water for 11 weeks, respectively. The results showed that compared with the control group, fluoride contents in three treatment groups were significantly increased and the structure of testes was seriously injured. The testosterone contents and the sperm count were decreased. Sperm malformation ratio was distinctly elevated. The expressions of Sly and HSF2 mRNA were markedly reduced in 100 mg/L NaF group and Ssty2 mRNA expression was dramatically decreased in 50 and 100 mg/L NaF groups. Meanwhile, the protein levels of Ssty2 and Sly were significantly reduced in 50 and 100 mg/L NaF groups and HSF2 protein levels were significantly decreased in 100 mg/L NaF group. These studies indicated that fluoride had toxic effects on male reproductive system by reducing the testosterone and sperm count, and increasing the sperm malformation ratio, supported by the damage of testicular structure, as a consequence of depressed HSF2 level, which resulted in the down-regulation of Ssty2 and Sly mRNA and protein.

Bone morphogenetic protein 4 and retinoic acid trigger bovine VASA homolog expression in differentiating bovine induced pluripotent stem cells

Primordial germ cells (PGCs) are the earliest identifiable and completely committed progenitors of female and male gametes. They are obvious targets for genome editing because they assure the transmission of desirable or introduced traits to future generations. PGCs are established at the earliest stages of embryo development and are difficult to propagate in vitro--two characteristics that pose a problem for their practical application. One alternative method to enrich for PGCs in vitro is to differentiate them from pluripotent stem cells derived from adult tissues. Here, we establish a reporter system for germ cell identification in bovine pluripotent stem cells based on green fluorescent protein expression driven by the minimal essential promoter of the bovine Vasa homolog (BVH) gene, whose regulatory elements were identified by orthologous modelling of regulatory units. We then evaluated the potential of bovine induced pluripotent stem cell (biPSC) lines carrying the reporter construct to differentiate toward the germ cell lineage. Our results showed that biPSCs undergo differentiation as embryoid bodies, and a fraction of the differentiating cells expressed BVH. The rate of differentiation towards BVH-positive cells increased up to tenfold in the presence of bone morphogenetic protein 4 or retinoic acid. Finally, we determined that the expression of key PGC genes, such as BVH or SOX2, can be modified by pre-differentiation cell culture conditions, although this increase is not necessarily mirrored by an increase in the rate of differentiation.

HSP70 overexpression may play a protective role in the mouse embryos stimulated by CUMS

BACKGROUND

We evaluated whether heat shock protein HSP70 plays a protective role in the embryos of Kunming mice subjected to chronic unpredictable mild stress.

METHODS

Female mice were stimulated for 4 weeks with nine stressors and then divided into mild, moderate and severe stress groups. Superovulation was induced with a gonadotropin preparation (PMSG/HCG) and HSP70 expression in 2-cell embryos and day 4 embryos was detected by immunofluorescence (IF) and real-time polymerase chain reaction (RT-PCR).

RESULTS

In the mild stress group, ovarian response and oocyte development potential were similar to those of the control group, while the HSP70 mRNA levels of the embryos were significantly higher (P < 0.05). In the severe stress group, ovarian response and oocyte development potential decreased compared with the control group (P < 0.05), while the HSP70 mRNA levels were similar. The results of the moderate stress group were intermediate among the three groups. Furthermore, HSP70 mRNA levels of the embryos were shown to be positively associated with parameters of oocyte and embryo development potential (P < 0.05).

CONCLUSIONS

HSP70 overexpression may play a protective role in the embryos of the mild or moderate stress mice stimulated by chronic unpredictable mild stress.