The fragilis interferon-inducible gene family of transmembrane proteins is associated with germ cell specification in mice

Biochemical evidence for conformational variants in the anti-viral and pro-metastatic protein IFITM1

Interferon induced transmembrane proteins (IFITMs) play a dual role in the restriction of RNA viruses and in cancer progression, yet the mechanism of their action remains unknown. Currently, there is no data about the basic biochemical features or biophysical properties of the IFITM1 protein. In this work, we report on description and biochemical characterization of three conformational variants/oligomeric species of recombinant IFITM1 protein derived from an Escherichia coli expression system. The protein was extracted from the membrane fraction, affinity purified, and separated by size exclusion chromatography where two distinct oligomeric species were observed in addition to the expected monomer. These species remained stable upon re-chromatography and were designated as "dimer" and "oligomer" according to their estimated molecular weight. The dimer was found to be less stable compared to the oligomer using circular dichroism thermal denaturation and incubation with a reducing agent. A two-site ELISA and HDX mass spectrometry suggested the existence of structural motif within the N-terminal part of IFITM1 which might be significant in oligomer formation. Together, these data show the unusual propensity of recombinant IFITM1 to naturally assemble into very stable oligomeric species whose study might shed light on IFITM1 anti-viral and pro-oncogenic functions in cells.

IFITM3-mediated activation of TRAF6/MAPK/AP-1 pathways induces acquired TKI resistance in clear cell renal cell carcinoma

PURPOSE

Vascular endothelial growth factor tyrosine kinase inhibitors (TKIs) have been the standard of care for advanced and metastatic clear cell renal cell carcinoma (ccRCC). However, the therapeutic effect of TKI monotherapy remains unsatisfactory given the high rates of acquired resistance to TKI therapy despite favorable initial tumor response.

MATERIALS AND METHODS

To define the TKI-resistance mechanism and identify new therapeutic target for TKI-resistant ccRCC, an integrative differential gene expression analysis was performed using acquired resistant cohort and a public dataset. Sunitinib-resistant RCC cell lines were established and used to test their malignant behaviors of TKI resistance through in vitro and in vivo studies. Immunohistochemistry was conducted to compare expression between the tumor and normal kidney and verify expression of pathway-related proteins.

RESULTS

Integrated differential gene expression analysis revealed increased interferon-induced transmembrane protein 3 (IFITM3) expression in post-TKI samples. IFITM3 expression was increased in ccRCC compared with the normal kidney. TKI-resistant RCC cells showed high expression of IFITM3 compared with TKI-sensitive cells and displayed aggressive biologic features such as higher proliferative ability, clonogenic survival, migration, and invasion while being treated with sunitinib. These aggressive features were suppressed by the inhibition of IFITM3 expression and promoted by IFITM3 overexpression, and these findings were confirmed in a xenograft model. IFITM3-mediated TKI resistance was associated with the activation of TRAF6 and MAPK/AP-1 pathways.

CONCLUSIONS

These results demonstrate IFITM3-mediated activation of the TRAF6/MAPK/AP-1 pathways as a mechanism of acquired TKI resistance, and suggest IFITM3 as a new target for TKI-resistant ccRCC.

Bisphenols and perfluoroalkyls alter human stem cells integrity: A possible link with infertility

Bisphenols and Perfluoroalkyls are chemical compounds widely used in industry known to be endocrine disruptors (EDs). Once ingested through contaminated aliments, they mimic the activity of endogenous hormones leading to a broad spectrum of diseases. Due to the extensive use of plastic in human life, particular attention should be paid to antenatal exposure to Bisphenols and Perfluoroalkyls since they cross the placental barrier and accumulates in developing embryo. Here we investigated the effects of Bisphenol-A (BPA), Bisphenol-S (BPS), perfluorooctane-sulfonate (PFOS) and perfluorooctanoic-acid (PFOA), alone or combined, on human-induced pluripotent stem cells (hiPSCs) that share several biological features with the stem cells of blastocysts. Our data show that these EDs affect hiPSC inducing a great mitotoxicity and dramatic changes in genes involved in the maintenance of pluripotency, germline specification, and epigenetic regulation. We also evidenced that these chemicals, when combined, may have additive, synergistic but also negative effects. All these data suggest that antenatal exposure to these EDs may affect the integrity of stem cells in the developing embryos, interfering with critical stages of early human development that might be determinant for fertility. The observation that the effects of exposure to a combination of these chemicals are not easily foreseeable further highlights the need for wider awareness of the complexity of the EDs effects on human health and of the social and economic burden attributable to these compounds.

The novel role of IFITM1-3 in myogenic differentiation of C2C12 cells

Interferon-induced transmembrane proteins (IFITMs 1, 2, and 3) play a critical role in preventing pathogen infection in vertebrates. They are also involved in the occurrence and prognosis of cancer. Myogenesis is a complex process regulated by several factors. This study disclosed that Ifitm1-3 were upregulated in the process of myogenic differentiation of C2C12 myoblasts on days 3, 5, and 7. This positively correlated with the expression of differentiation factors MyoD, myogenin, Mrf5, and desmin. Furthermore, knockdown of Ifitm1-3 by their individual siRNAs inhibited myogenesis of C2C12 myoblasts, with relative downregulation of MyoD, myogenin, Mrf5, and desmin. Subsequently, myotube formation and fusion percentage decreased. Co-immunoprecipitation combined with LC-MS/MS analysis uncovered the interaction proteins of IFITM1 and IFITM3 in C2C12 myoblasts. A total of 84 overlapped interaction proteins of IFITM1 and IFITM3 were identified, and one of the clusters was engaged in cytoskeletal and sarcomere proteins, including desmin, myosin, actin, vimentin, nestin, ankycorbin, and nucleolin. Hence, we hypothesize that these interacting proteins may function as scaffolds for IFITM1-3, possibly through the interaction protein desmin to initiate further interaction with other proteins to participate in myogenesis; however, the molecular mechanisms remain unclear. Our study may contribute to the development of novel therapeutics for myopathic diseases.

A Mesp1-dependent developmental breakpoint in transcriptional and epigenomic specification of early cardiac precursors

Transcriptional networks governing cardiac precursor cell (CPC) specification are incompletely understood owing, in part, to limitations in distinguishing CPCs from non-cardiac mesoderm in early gastrulation. We leveraged detection of early cardiac lineage transgenes within a granular single-cell transcriptomic time course of mouse embryos to identify emerging CPCs and describe their transcriptional profiles. Mesp1, a transiently expressed mesodermal transcription factor, is canonically described as an early regulator of cardiac specification. However, we observed perdurance of CPC transgene-expressing cells in Mesp1 mutants, albeit mislocalized, prompting us to investigate the scope of the role of Mesp1 in CPC emergence and differentiation. Mesp1 mutant CPCs failed to robustly activate markers of cardiomyocyte maturity and crucial cardiac transcription factors, yet they exhibited transcriptional profiles resembling cardiac mesoderm progressing towards cardiomyocyte fates. Single-cell chromatin accessibility analysis defined a Mesp1-dependent developmental breakpoint in cardiac lineage progression at a shift from mesendoderm transcriptional networks to those necessary for cardiac patterning and morphogenesis. These results reveal Mesp1-independent aspects of early CPC specification and underscore a Mesp1-dependent regulatory landscape required for progression through cardiogenesis.

Predicting diagnostic gene expression profiles associated with immune infiltration in patients with lupus nephritis

Objective

To identify potential diagnostic markers of lupus nephritis (LN) based on bioinformatics and machine learning and to explore the significance of immune cell infiltration in this pathology.

Methods

Seven LN gene expression datasets were downloaded from the GEO database, and the larger sample size was used as the training group to obtain differential genes (DEGs) between LN and healthy controls, and to perform gene function, disease ontology (DO), and gene set enrichment analyses (GSEA). Two machine learning algorithms, least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE), were applied to identify candidate biomarkers. The diagnostic value of LN diagnostic gene biomarkers was further evaluated in the area under the ROC curve observed in the validation dataset. CIBERSORT was used to analyze 22 immune cell fractions from LN patients and to analyze their correlation with diagnostic markers.

Results

Thirty and twenty-one DEGs were screened in kidney tissue and peripheral blood, respectively. Both of which covered macrophages and interferons. The disease enrichment analysis of DEGs in kidney tissues showed that they were mainly involved in immune and renal diseases, and in peripheral blood it was mainly enriched in cardiovascular system, bone marrow, and oral cavity. The machine learning algorithm combined with external dataset validation revealed that C1QA(AUC = 0.741), C1QB(AUC = 0.758), MX1(AUC = 0.865), RORC(AUC = 0.911), CD177(AUC = 0.855), DEFA4(AUC= 0.843)and HERC5(AUC = 0.880) had high diagnostic value and could be used as diagnostic biomarkers of LN. Compared to controls, pathways such as cell adhesion molecule cam, and systemic lupus erythematosus were activated in kidney tissues; cell cycle, cytoplasmic DNA sensing pathways, NOD-like receptor signaling pathways, proteasome, and RIG-1-like receptors were activated in peripheral blood. Immune cell infiltration analysis showed that diagnostic markers in kidney tissue were associated with T cells CD8 and Dendritic cells resting, and in blood were associated with T cells CD4 memory resting, suggesting that CD4 T cells, CD8 T cells and dendritic cells are closely related to the development and progression of LN.

Conclusion

C1QA, C1QB, MX1, RORC, CD177, DEFA4 and HERC5 could be used as new candidate molecular markers for LN. It may provide new insights into the diagnosis and molecular treatment of LN in the future.

IFITM protein regulation and functions: Far beyond the fight against viruses

Interferons (IFNs) are important cytokines that regulate immune responses through the activation of hundreds of genes, including interferon-induced transmembrane proteins (IFITMs). This evolutionarily conserved protein family includes five functionally active homologs in humans. Despite the high sequence homology, IFITMs vary in expression, subcellular localization and function. The initially described adhesive and antiproliferative or pro-oncogenic functions of IFITM proteins were diluted by the discovery of their antiviral properties. The large set of viruses that is inhibited by these proteins is constantly expanding, as are the possible mechanisms of action. In addition to their beneficial antiviral effects, IFITM proteins are often upregulated in a broad spectrum of cancers. IFITM proteins have been linked to most hallmarks of cancer, including tumor cell proliferation, therapeutic resistance, angiogenesis, invasion, and metastasis. Recent studies have described the involvement of IFITM proteins in antitumor immunity. This review summarizes various levels of IFITM protein regulation and the physiological and pathological functions of these proteins, with an emphasis on tumorigenesis and antitumor immunity.

MiR-504-3p Has Tumor-Suppressing Activity and Decreases IFITM1 Expression in Non-Small Cell Lung Cancer Cells

Objective: To analyze the impact of expression of miR-504-3p on the proliferation, migration, cell cycle transit and rate of apoptosis of NSCLC cells and explore the underlying mechanisms. Methods: The Cancer Genome Atlas (TCGA) database was used to compare the expression levels of miR-504 between NSCLC tissues and normal lung tissues. NSCLC cells were transfected with lentiviral vectors that either overexpressed or knocked down miR-504-3p to evaluate its effects on NSCLC biological behavior. Quantitative Real Time Polymerase Chain Reaction was used to measure the levels of miR-504-3p and Interferon-Induced Transmembrane Protein 1 (IFITM1). A luciferase reporter array was used to reveal whether miR-504-3p directly targets IFITM1. Results: The expression of miR-504 was significantly down-regulated in lung cancer tissues compared to normal lung tissues. Overexpression of miR-504-3p in NSCLC cell lines inhibited cell proliferation, migration and promoted cell apoptosis. Meanwhile, changes in the expression level of miR-504-3p had no significant effect on NSCLC cell cycle progression. Moreover, over-expressed miR-504-3p following its transfection significantly decreased the expression of IFITM1 in NSCLC cell lines and suppressed the activity of the luciferase reporter containing wild type but not mutant IFITM1 3' -UTR. Conclusion: miR-504-3p inhibits cell proliferation and migration and promotes cell apoptosis in NSCLC cells. MiR-504-3p decreases IFITM1 expression in NSCLC cells, which may be a potential mechanism of its tumor-suppressive functions in NSCLC.

Role of the Circadian Clock "Death-Loop" in the DNA Damage Response Underpinning Cancer Treatment Resistance

Here, we review the role of the circadian clock (CC) in the resistance of cancer cells to genotoxic treatments in relation to whole-genome duplication (WGD) and telomere-length regulation. The CC drives the normal cell cycle, tissue differentiation, and reciprocally regulates telomere elongation. However, it is deregulated in embryonic stem cells (ESCs), the early embryo, and cancer. Here, we review the DNA damage response of cancer cells and a similar impact on the cell cycle to that found in ESCs—overcoming G1/S, adapting DNA damage checkpoints, tolerating DNA damage, coupling telomere erosion to accelerated cell senescence, and favouring transition by mitotic slippage into the ploidy cycle (reversible polyploidy). Polyploidy decelerates the CC. We report an intriguing positive correlation between cancer WGD and the deregulation of the CC assessed by bioinformatics on 11 primary cancer datasets (rho = 0.83; p < 0.01). As previously shown, the cancer cells undergoing mitotic slippage cast off telomere fragments with TERT, restore the telomeres by ALT-recombination, and return their depolyploidised offspring to telomerase-dependent regulation. By reversing this polyploidy and the CC “death loop”, the mitotic cycle and Hayflick limit count are thus again renewed. Our review and proposed mechanism support a life-cycle concept of cancer and highlight the perspective of cancer treatment by differentiation.

LncRNA IFITM4P regulates host antiviral responses by acting as a ceRNA

Long noncoding RNAs (lncRNAs) are involved in numerous cellular processes. Increasing evidence suggests that some lncRNAs function in immunity through various complex mechanisms. However, implication of a large fraction of lncRNAs in antiviral innate immunity remains uncharacterized. Here, we identified a lncRNA called lncRNA IFITM4P that was transcribed from interferon induced transmembrane protein 4 pseudogene (IFITM4P), a pseudogene belonging to interferon induced transmembrane protein (IFITM) family. We found that expression of lncRNA IFITM4P was significantly induced by infection with several viruses including influenza A virus (IAV). Importantly, lncRNA IFITM4P acted as a positive regulator of innate antiviral immunity. Ectopic expression of lncRNA IFITM4P significantly suppressed IAV replication in vitro, whereas IFITM4P deficiency promoted the viral production. We further observed that expression of lncRNA IFITM4P was up-regulated by interferon (IFN) signaling during viral infection, and altering the expression of this lncRNA had significant effects on the mRNA levels of several IFITM family members including IFITM1, IFITM2 and IFITM3. Moreover, it was identified that lncRNA IFITM4P was a target of miR-24-3p that represses mRNA of IFITM1, IFITM2 and IFITM3. The experiments demonstrated that lncRNA IFITM4P was able to cross-regulate the expression of IFITM family members as a competing endogenous RNA (ceRNA), leading to increased stability of these IFITM mRNAs. Together, our results reveal that lncRNA IFITM4P, as a ceRNA, is involved in innate immunity against viral infection through the lncRNA IFITM4P-miR-24-3p- IFITM1/2/3 regulatory network. IMPORTANCE LncRNAs play important roles in various biological processes, but their involvement in host antiviral responses remains largely unknown. In this study, we revealed that the pseudogene IFITM4P belonging to IFITM family can transcribe a functional long noncoding RNA termed lncRNA IFITM4P. Importantly, results showed that lncRNA IFITM4P was involved in innate antiviral immunity, which resembles some interferon-stimulated genes (ISGs). Furthermore, lncRNA IFITM4P was identified as a target of miR-24-3p and acts as a ceRNA to inhibit the replication of IAV through regulating the mRNA levels of IFITM1, IFITM2 and IFITM3. These data provide a new insight into the role of a previously uncharacterized lncRNA encoded by a pseudogene in the host antiviral response, and a better understanding of the IFITM antiviral network.

Female Germ Cell Development, Functioning and Associated Adversities under Unfavorable Circumstances

In the present era, infertility is one of the major issues which restricts many couples to have their own children. Infertility is the inability to achieve a clinical pregnancy after regular unprotected sexual intercourse for the period of one year or more. Various factors including defective male or female germ cell development, unhealthy and improper lifestyles, diseases like cancer and associated chemo-or-radiation therapies, congenital disorders, etc., may be responsible for infertility. Therefore, it is highly important to understand the basic concepts of germ cell development including primordial germ cell (PGC) formation, specification, migration, entry to genital ridges and their molecular mechanisms, activated pathways, paracrine and autocrine signaling, along with possible alteration which can hamper germ cell development and can cause adversities like cancer progression and infertility. Knowing all these aspects in a proper way can be very much helpful in improving our understanding about gametogenesis and finding possible ways to cure related disorders. Here in this review, various aspects of gametogenesis especially female gametes and relevant factors causing functional impairment have been thoroughly discussed.

Malignancy and IFITM3: Friend or Foe?

The prevalence and incidence of cancers has risen over the last decade. Available treatments have improved outcomes, yet mortality and morbidity remain high, creating an urgent demand for personalized and new therapy targets. Interferon induced transmembrane protein (IFITM3) is highly expressed in cancers and is a marker of poor prognosis. In this review, we discuss recent advances in IFITM3 biology, the regulatory pathways, and its function within cancer as part of immunity and maintaining stemness. Overexpression of IFITM3 is likely an indirect effect of ongoing inflammation, immune and cancer epithelial-to-mesenchymal (EMT) related pathways i.e., interferons, TGF-β, WNT/β-catenin, etc. However, IFITM3 also influences tumorigenic phenotypes, such as cell proliferation, migration and invasion. Furthermore, IFITM3 plays a key role in cancer growth and maintenance. Silencing of IFITM3 reduces these phenotypes. Therefore, targeting of IFITM3 will likely have implications for potential cancer therapies.

Comparison of RNA m6A and DNA methylation profiles between mouse female germline stem cells and STO cells

N⁶-methyladenosine (m⁶A) methylation modification is the most prevalent and abundant internal modification of eukaryotic mRNAs. Increasing evidence has shown that mRNA m⁶A plays important roles in the development of stem cells. However, to the best of our knowledge, no reports about the roles of mRNA m⁶A in mouse female germline stem cells (mFGSCs) have been published. In this study, we compared the genome-wide profiles of mRNA m⁶A methylation and DNA methylation between FGSCs and sandosinbred mice (SIM) embryo-derived thioguanine and ouabain-resistant (STO) cells. qRT-PCR revealed that the expression levels of mRNA m⁶A-related genes (Mettl3, Alkbh5, Ythdf1, Ythdf2, Ythdc1, and Ythdc2) in FGSCs were significantly higher than those in STO cells. m⁶A RNA immunoprecipitation sequencing (MeRIP-seq) data further showed that the unique m⁶A-methylated mRNAs in FGSCs and STO cells were related to cell population proliferation and somatic development, respectively. Additionally, knockdown of Ythdf1 inhibited FGSC self-renewal. Comparison of methylated DNA immunoprecipitation sequencing (MeDIP-seq) results between FGSCs and STO cells identified that DNA methylation contributed to FGSC proliferation by suppressing the somatic program. These results suggested that m⁶A regulated FGSC self-renewal possibly through m⁶A binding protein YTHDF1, and DNA methylation repressed somatic programs in FGSCs to maintain FGSC characteristics.

The IFITM protein family in adaptive immunity

Interferon‐inducible transmembrane (IFITM) proteins are a family of small homologous proteins, localized in the plasma and endolysosomal membranes, which confer cellular resistance to many viruses. In addition, several distinct functions have been associated with different IFITM family members, including germ cell specification (IFITM1–IFITM3), osteoblast function and bone mineralization (IFITM5) and immune functions (IFITM1–3, IFITM6). IFITM1–3 are expressed by T cells and recent experiments have shown that the IFITM proteins are directly involved in adaptive immunity and that they regulate CD4⁺ T helper cell differentiation in a T‐cell‐intrinsic manner. Here we review the role of the IFITM proteins in T‐cell differentiation and function.

Distinct roles of retinoic acid and BMP4 pathways in the formation of chicken primordial germ cells and spermatogonial stem cells

This study demonstrated different effects of bone morphogenetic protein 4 (BMP4) and retinoic acid (RA) signaling on the induction of germ cell formation in chickens. In vitro, BMP4 significantly promoted primordial germ cell (PGC) formation, while RA promoted spermatogonial stem cell (SSC) formation. Hematoxylin-Eosin (HE) staining of reproductive ridge and testicular slices showed that BMP4 signaling was activated during PGC formation but was inhibited during PGC differentiation into SSC. In contrast, RA signaling was significantly activated during PGC differentiation to SSC. Mechanistically, elevated expression of phosphorylated mothers against decapentaplegic homolog 5 (p-Smad5) activated BMP4 signaling, while inhibition of p-Smad5 significantly reduced the PGC formation. Additionally, BMP4 regulated the PGC formation through histone acetylation and DNA methylation in deleted in azoospermia-like (DAZL) gene. Luciferase report showed RA binding to RARα regulated stimulated by RA 8 (Stra8) promoter activity during SSC formation, while mutations in RAR binding sites inhibited the Stra8 expression and SSC formation. Further, both HAT and HDAC regulated the RARα isoform, and HAT binding to RARα activated the Stra8 transcription. RNA-seq of embryonic stem cells (ESC), PGC, and SSC showed inverse expression of genes related to the BMP4 and RA pathways during PGC and SSC formation. Additionally, Smad5 and Smurf were critical for the interactions between the two pathways. Specifically, through Smurf promotion of Smad5 ubiquitination, RA could inhibit the BMP4 signal transduction. In conclusion, the BMP4 and RA signaling pathways play opposing roles in germ cell formation, driven by epigenetic processes such as phosphorylation, ubiquitination, and histone acetylation.

IFITM3 knockdown reduces the expression of CCND1 and CDK4 and suppresses the growth of oral squamous cell carcinoma cells

PURPOSE

Oral squamous cell carcinoma (OSCC) is a challenging disease to treat. Up to 50% of OSCC patients with advanced disease develop recurrences. Elucidation of key molecular mechanisms underlying OSCC development may provide opportunities to target specific genes and, thus, to improve patient survival. In this study, we examined the expression and functional role of interferon transmembrane protein 3 (IFITM3) in OSCC development.

METHODS

The expression of IFITM3 in OSCC and normal oral mucosal tissues was assessed by qRT-PCR and immunohistochemistry. The role of IFITM3 in driving OSCC cell proliferation and survival was examined using siRNA-mediated gene knockdown, and the role of IFITM3 in driving cell cycle regulators was examined using Western blotting.

RESULTS

We found that IFITM3 is overexpressed in more than 79% of primary OSCCs. We also found that IFITM3 knockdown led to impaired OSCC cell growth through inhibition of cell proliferation, induction of cell cycle arrest, senescence and apoptosis. In addition, we found that IFITM3 knockdown led to reduced expressions of CCND1 and CDK4 and reduced RB phosphorylation, leading to inhibition of OSCC cell growth. This information may be instrumental for the design of novel targeted therapeutic strategies.

CONCLUSIONS

From our data we conclude that IFITM3 is overexpressed in OSCC and may regulate the CCND1-CDK4/6-pRB axis to mediate OSCC cell growth.

Modern Technologies Deriving Human Primordial Germ Cells in vitro

Primordial germ cells (PGCs) are a unique type of stem cells capable of giving rise to totipotent stem cells and ensuring the fertility of an organism and the transfer of its genome to the next generation. PGC research is an important perspective research field of developmental biology that handles many questions of embryogenesis and holds promise for treatments of infertility in the future. Considering ethical concerns related to human embryos, the main research approach in understanding the biology of human PGCs is in vitro studies. In this review, we consider the historical perspective of human PGC studies in vitro, the main existing models, and further outlooks and applications in medicine and science.

IFITM5 pathogenic variant causes osteogenesis imperfecta V with various phenotype severity in Ukrainian and Vietnamese patients

BACKGROUND

Osteogenesis imperfecta (OI) covers a spectrum of bone fragility disorders. OI is classified into five types; however, the genetic causes of OI might hide in pathogenic variants of 20 different genes. Often clinical OI types mimic each other. This sometimes makes it impossible to identify the OI type clinically, which can be a risk for patients. Up to 90% of OI types I-IV are caused by pathogenic variants in the COL1A1/2 genes. OI type V is caused by the c.-14C > T pathogenic variant in the 5'UTR of the IFITM5 gene and is characterized by hyperplastic callus formation and the ossification of interosseous membranes.

RESULTS

In the current study, we performed IFITM5 5'UTR region mutational analysis using Sanger sequencing on 90 patients who were negative for COL1A1/2 pathogenic variants. We also investigated the phenotypes of five patients with genetically confirmed OI type V. The proportion of OI type V patients in our cohort of all OI patients was 1.48%. In one family, there was a history of OI in at least three generations. Phenotype severity differed from mild to extremely severe among patients, but all patients harbored the same typical pathogenic variant. One patient had no visible symptoms of OI type V and was suspected to have had OI type IV previously. We also identified a case of extremely severe hyperplastic callus in a 15-year-old male, who has hearing loss and brittleness of teeth.

CONCLUSIONS

OI type V is underlined with some unique clinical features; however, not all patients develop them. The phenotype spectrum might be even broader than previously suspected, including typical OI features: teeth brittleness, bluish sclera, hearing loss, long bones deformities, and joint laxity. We suggest that all patients negative for COL1A1/2 pathogenic variants be tested for the presence of an IFITM5 pathogenic variant, even if they are not expressing typical OI type V symptoms. Further studies on the pathological nature and hyperplastic callus formation mechanisms of OI type V are necessary.

Characterization of female germline stem cells from adult mouse ovaries and the role of rapamycin on them

Germline stem cells (GSCs) play an indispensable role in establishing the fertility of an organism. The isolation and culture of adult female GSCs (FGSCs) have provided a robust foundation to study the development of female germ cells in rodents. However, many problems still need to be identified, such as the origin and location of FGSCs and the specific markers for screening. In this study, we acquired FGSCs that stably expressed Oct4 from Oct4 promoter-GFP transgenic mouse ovarian surface epithelium and cortical layer, and identified the cells possessing the representative features including the expression of GSCs marker genes and the potentiality of differentiation into all three germ layers in vitro. Moreover, rapamycin was confirmed to promote proliferation of mouse FGSCs and inhibit the differentiation capability in vivo. In addition to the reported disinfection function, rapamycin inhibited the activation of primordial follicles, as the inhibitor of mechanistic target of rapamycin pathway. These results will contribute to the study on folliculogenesis or oogenesis mechanism and have important implications on developing new technology and therapeutic approach in medicine for premature ovarian failure, infertility and even ovary remodelling in future.

Mouse Germ Cell Development in-vivo and in-vitro

In mammalian development, primordial germ cells (PGCs) represent the initial population of cells that are committed to the germ cell lineage. PGCs segregate early in development, triggered by signals from the extra-embryonic ectoderm. They are distinguished from surrounding cells by their unique gene expression patterns. Some of the more common genes used to identify them are Blimp1, Oct3/4, Fragilis, Stella, c-Kit, Mvh, Dazl and Gcna1. These genes are involved in regulating their migration and differentiation, and in maintaining the pluripotency of these cells.

Recent research has demonstrated the possibility of obtaining PGCs, and subsequently, mature germ cells from a starting population of embryonic stem cells (ESCs) in culture. This phenomenon has been investigated using a variety of methods, and ESC lines of both mouse and human origin. Embryonic stem cells can differentiate into germ cells of both the male and female phenotype and in one case has resulted in the birth of live pups from the fertilization of oocytes with ESC derived sperm. This finding leads to the prospect of using ESC derived germ cells as a treatment for sterility. This review outlines the evolvement of germ cells from ESCs in vitro in relation to in vivo events.

The expression profile of IFITM family gene in rats

The interferon-inducible transmembrane proteins (IFITMs) are a family of small transmembrane proteins belonging to the interferon (IFN)-stimulated gene (ISG) superfamily and strongly induced by IFNs. In this paper, we studied the expression profile of IFITMs in 32 organ tissues. The IFITM mRNA expression profile showed that IFITM1, IFITM2 and IFITM3 were expressed in each tissue, especially, in spermatophore, spermaduct, testicle and epididymis. The expression of IFITM1, IFITM2 and IFITM3 showed a trend from high to low. Except for IFITM3 and IFITM6, the others IFITMs were highly expressed in the bone marrow, and the expression level of them was higher in the tibia than that in other parts of the long bones. In liver, the relative expression of IFITM1 and IFITM3 was higher than that of other members. The expression level of IFITM5 was the highest in bone marrow, successively in pancreas, and it was low in skin, smooth muscle and fat. Interestingly, the expression profile of IFITM2 and IFITM7 in tissues was similar to IFITM5. The expression of IFITM2, IFITM5 and IFITM10 were higher in smooth muscle than that in skeletal muscle. IFITM2, IFITM5, IFITM7 and IFITM10 were both highly expressed in esophagus and trachea. In addition, the expression of IFITM6 in eyes was high, and also in pancreas, gallbladder and bone. In the present study, we systematically analyzed the mRNA expression profile of IFITMs in 32 organ tissues, providing the foundation for the study of the function of the IFITMs.

The osteogenic cell surface marker BRIL/IFITM5 is dispensable for bone development and homeostasis in mice

BRIL (bone-restricted IFITM-like), is a short transmembrane protein expressed almost exclusively in osteoblasts. Although much is known about its bone-restricted gene expression pattern and protein biochemical and topological features, little information is available for BRIL physiological function. Two autosomal dominant forms of osteogenesis imperfecta (OI) are caused by distinct, but recurrent mutations in the BRIL gene. Yet, the underlying mechanisms by which those mutations lead to OI are still poorly understood. A previous report indicated that BRIL knockout (KO) mice had bone deformities, shortened long bones, and reproductive problems. Here we generated and systematically analyzed the skeletal phenotype of a new global Bril KO/LacZ knockin mouse model. KO mice reproduced and thrived normally up to 12 month of age. The skeletal phenotype of KO and WT littermates was assessed at embryonic (E13.5 to E18.5) and postnatal (2 days, 3 weeks, 3 months and 8 months) time-points. Embryos from E13.5 through to E18.5 showed significant X-Gal staining in all skeletal elements without any apparent patterning anomalies. Although bone deformities were never observed at any postnatal ages, minor and transient differences were noted in terms of bone length and static uCT parameters, but not systematically across all ages and genders. These changes, however, were not accompanied by significant alteration in bone material properties as assessed by a 3-point bending test. In addition, no changes were detected in circulating serum markers of bone turnover (P1NP, CTX-I, and osteocalcin). Gene expression monitoring also revealed no major impact of the loss of BRIL. Further, when mice were challenged with a surgically-induced fracture in tibia, bones repaired equally well in the KO mice as compared to WT. Finally, we showed that BRIL C-terminus is not a bona fide binding site for calcium. In conclusion, our in depth analysis suggest that skeletal patterning, bone mass accrual and remodeling in mice proceeded independent of BRIL.

Genetic causes and mechanisms of Osteogenesis Imperfecta

Osteogenesis Imperfecta (OI) is a genetic disorder characterized by various clinical features including bone deformities, low bone mass, brittle bones, and connective tissue manifestations. The predominant cause of OI is due to mutations in the two genes that encode type I collagen. However, recent advances in sequencing technology has led to the discovery of novel genes that are implicated in recessive and dominant OI. These include genes that regulate the post-translational modification, secretion and processing of type I collagen as well as those required for osteoblast differentiation and bone mineralization. As such, OI has become a spectrum of genetic disorders informing about the determinants of both bone quantity and quality. Here we summarize the known genetic causes of OI, animal models that recapitulate the human disease and mechanisms that underlie disease pathogenesis. Additionally, we discuss the effects of disrupted collagen networks on extracellular matrix signaling and its impact on disease progression.

Genetic studies in mice directly link oocytes produced during adulthood to ovarian function and natural fertility

Multiple labs have reported that mammalian ovaries contain oogonial stem cells (OSCs), which can differentiate into oocytes that fertilize to produce offspring. However, the physiological relevance of these observations to adult ovarian function is unknown. Here we performed targeted and reversible ablation of premeiotic germ cells undergoing differentiation into oocytes in transgenic mice expressing the suicide gene, herpes simplex virus thymidine kinase (HSVtk), driven by the promoter of stimulated by retinoic acid gene 8 (Stra8), a germ cell-specific gene activated during meiotic commitment. Over a 21-day ablation phase induced by the HSVtk pro-drug, ganciclovir (GCV), oocyte numbers declined due to a disruption of new oocyte input. However, germ cell differentiation resumed after ceasing the ablation protocol, enabling complete regeneration of the oocyte pool. We next employed inducible lineage tracing to fate map, through Cre recombinase-mediated fluorescent reporter gene activation only in Stra8-expressing cells, newly-formed oocytes. Induction of the system during adulthood yielded a mosaic pool of unmarked (pre-existing) and marked (newly-formed) oocytes. Marked oocytes matured and fertilized to produce offspring, which grew normally to adulthood and transmitted the reporter to second-generation offspring. These findings establish that oocytes generated during adulthood contribute directly to ovarian function and natural fertility in mammals.

An Initial Investigation of an Alternative Model to Study rat Primordial Germ Cell Epigenetic Reprogramming

BACKGROUND

Primordial germ cells (PGC) are the precursors of the gametes. During pre-natal development, PGC undergo an epigenetic reprogramming when bulk DNA demethylation occurs and is followed by sex-specific de novo methylation. The de novo methylation and the maintenance of the methylation patterns depend on DNA methyltransferases (DNMTs). PGC reprogramming has been widely studied in mice but not in rats. We have previously shown that the rat might be an interesting model to study germ cell development. In face of the difficulties of getting enough PGC for molecular studies, the aim of this study was to propose an alternative method to study rat PGC DNA methylation. Rat embryos were collected at 14, 15 and 19 days post-coitus (dpc) for the analysis of 5mC, 5hmC, DNMT1, DNMT3a and DNMT3b expression or at 16dpc for treatment 5-Aza-CdR, a DNMT inhibitor, in vitro.

METHODS

Once collected, the gonads were placed in 24-well plates previously containing 45μm pore membrane and medium with or without 5-Aza-CdR. The culture was kept for five days and medium was changed daily. The gonads were either fixed or submitted to RNA extraction.

RESULTS

5mC and DNMTs labelling suggests that PGC are undergoing epigenetic reprogramming around 14/15dpc. The in vitro treatment of rat embryonic gonads with 1 μM of 5-Aza-CdR lead to a loss of 5mC labelling and to the activation of Pax6 expression in PGC, but not in somatic cells, suggesting that 5-Aza-CdR promoted a PGC-specific global DNA hypomethylation.

CONCLUSIONS

This study suggests that the protocol used here can be a potential method to study the wide DNA demethylation that takes place during PGC reprogramming.

Localization and distribution of gonadal proteins in the oviparous lizard Sceloporus aeneus (Squamata: Phrynosomatidae)

Among vertebrates, several specific proteins are involved in the function and development of gonads. Several genes such as SOX9, FOXL2, DDX4, IFITM3, and DPPA3, are active during embryonic differentiation and maintain their expression in adult tissues, playing important roles in the function and development of the line cell, where these are produced. Among reptiles, molecular mechanisms for sex differentiation have been analyzed in turtles, crocodiles, and some lizards, while in adult stages such studies are scarce. The aim of this study was to locate and analyze the distribution of important gonadal proteins in adult and embryonic ovaries and testes of the oviparous lizard Sceloporus aeneus (Squamata: Phrynosomatidae). Adult specimens and embryos of the lizard S. aeneus were collected in Milpa Alta, a suburb located Southwest of Mexico City. Expression of gonadal proteins was analyzed using immunofluorescent staining and confocal microscopy. Our results showed that SOX9 is located in Sertoli cells of embryonic and adult testes. FOXL2 is expressed in follicular cells of adult ovaries. DDX4 and IFITM3 are located in germ line cells as well as in follicular cells of adult ovaries. DPPA3 was observed in somatic and germ line cells of adult and embryonic gonads. Our observations show that important molecules of vertebrate ovaries and testes are conserved in S. aeneus and it is suggested that these may have a similar role during gonadal development and function.

Interferon induced transmembrane protein 3 regulates the growth and invasion of human lung adenocarcinoma

Background

Interferon induced transmembrane protein 3 (IFITM3) plays an important role in the tumorigenesis and progression of multiple cancers. This study investigated the expression and function of IFITM3 in human lung adenocarcinoma.

Methods

Fifty human lung adenocarcinoma tissues were collected. IFITM3 expression was assessed by immunohistochemical staining. The clinicopathologic characteristics of all patients were analyzed.

Results

IFITM3 was mainly detected in the cytoplasm of advanced cancer tissues and its expression was correlated with tumor malignancy grade. Knockdown of IFITM3 in vitro markedly inhibited the proliferation and invasion of lung adenocarcinoma cells.

Conclusion

IFITM3 represents a potential therapeutic target for the treatment of lung adenocarcinoma.

Identification of IFITM1 and IFITM3 in Goose: Gene Structure, Expression Patterns, and Immune Reponses against Tembusu Virus Infection

As interferon-stimulated genes (ISGs), interferon-inducible transmembrane proteins 1 and 3 (IFITM1 and IFITM3) can effectively inhibit the replication of multiple viruses. Here, goose IFITM1 and IFITM3 were cloned and identified for the first time. The two proteins share the same topological structure and several important sites critical for the antiviral functions in other species are conserved in the goose. Goose IFITM1 and IFITM3 are most closely related to their respective orthologs in ducks; these proteins exhibited high mRNA transcript levels in immune-related tissues, including the thymus, bursa of Fabricius, and Harderian gland, compared to other tissues. Moreover, goose IFITM1 was highly constitutively expressed in gastrointestinal tract tissues, while goose IFITM3 was expressed in respiratory organs. Furthermore, goose IFITM3 was activated in goose peripheral blood mononuclear cells (PBMCs) infected with Tembusu virus (TMUV) or treated with Toll-like receptors (TLRs) agonists, while only the R848 and Poly (I:C) agonists induced significant upregulation of goose IFITM1. Furthermore, goose IFITM1 and IFITM3 were upregulated in the sampled tissues, to some extent, after TMUV infection. Notably, significant upregulation of goose IFITM1 and IFITM3 was detected in the cecum and cecal tonsil, where TMUV was primarily distributed. These data provide new insights into the immune effectors in geese and promote our understanding of the role of IFITM1 and IFITM3 in the defense against TMUV.

Evaluation of interferon-induced transmembrane protein-3 (IFITM3) rs7478728 and rs3888188 polymorphisms and the risk of pulmonary tuberculosis

The current study aimed to examine the possible association between the interferon-induced transmembrane protein-3 (IFITM3) gene polymorphisms and risk of pulmonary tuberculosis (PTB) in a sample population. This case-control study was conducted on 188 PTB patients and 169 healthy subjects. The rs7478728 and rs3888188 variants of IFITM3 were genotyped using polymerase chain reaction-restriction fragment length polymorphism. The findings showed no significant association between rs7478728 polymorphism and risk of PTB. Regarding rs3888188 polymorphism, the TG genotype as well as G allele significantly increased the risk of PTB [odds ratio (OR)=2.48, 95% confidence interval (CI): 1.42-4.53; P=0.002, and OR=2.26, 95% CI: 1.33-3.86; P=0.003, respectively]. In conclusion, the findings revealed that rs3888188 polymorphism increased the risk of PTB in a sample of Iranian population. Additional investigation with larger sample sizes and different ethnicities are needed to verify our findings.

The Interferon-Stimulated Gene Ifitm3 Restricts West Nile Virus Infection and Pathogenesis

The interferon-induced transmembrane protein (IFITM) family of proteins inhibit infection of several different enveloped viruses in cell culture by virtue of their ability to restrict entry and fusion from late endosomes. As few studies have evaluated the importance of Ifitm3 in vivo in restricting viral pathogenesis, we investigated its significance as an antiviral gene against West Nile virus (WNV), an encephalitic flavivirus, in cells and mice. Ifitm3(-/-) mice were more vulnerable to lethal WNV infection, and this was associated with greater virus accumulation in peripheral organs and central nervous system tissues. As no difference in viral burden in the brain or spinal cord was observed after direct intracranial inoculation, Ifitm3 likely functions as an antiviral protein in nonneuronal cells. Consistent with this, Ifitm3(-/-) fibroblasts but not dendritic cells resulted in higher yields of WNV in multistep growth analyses. Moreover, transcomplementation experiments showed that Ifitm3 inhibited WNV infection independently of Ifitm1, Ifitm2, Ifitm5, and Ifitm6. Beyond a direct effect on viral infection in cells, analysis of the immune response in WNV-infected Ifitm3(-/-) mice showed decreases in the total number of B cells, CD4(+) T cells, and antigen-specific CD8(+) T cells. Finally, bone marrow chimera experiments demonstrated that Ifitm3 functioned in both radioresistant and radiosensitive cells, as higher levels of WNV were observed in the brain only when Ifitm3 was absent from both compartments. Our analyses suggest that Ifitm3 restricts WNV pathogenesis likely through multiple mechanisms, including the direct control of infection in subsets of cells.

IMPORTANCE

As part of the mammalian host response to viral infections, hundreds of interferon-stimulated genes (ISGs) are induced. The inhibitory activity of individual ISGs varies depending on the specific cell type and viral pathogen. Among ISGs, the genes encoding interferon-induced transmembrane protein (IFITM) have been reported to inhibit multiple families of viruses in cell culture. However, few reports have evaluated the impact of IFITM genes on viral pathogenesis in vivo In this study, we characterized the antiviral activity of Ifitm3 against West Nile virus (WNV), an encephalitic flavivirus, using mice with a targeted gene deletion of Ifitm3 Based on extensive virological and immunological analyses, we determined that Ifitm3 protects mice from WNV-induced mortality by restricting virus accumulation in peripheral organs and, subsequently, in central nervous system tissues. Our data suggest that Ifitm3 restricts WNV pathogenesis by multiple mechanisms and functions in part by controlling infection in different cell types.

Does mouse embryo primordial germ cell activation start before implantation as suggested by single-cell transcriptomics dynamics?

STUDY HYPOTHESIS

Does primordial germ cell (PGC) activation start before mouse embryo implantation, and does the possible regulation of the DNA (cytosine-5-)-methyltransferase 3-like (Dnmt3l) by transcription factor AP-2, gamma (TCFAP2C) have a role in this activation and in the primitive endoderm (PE)-epiblast (EPI) lineage specification?

STUDY FINDING

A burst of expression of PGC markers, such as Dppa3/Stella, Ifitm2/Fragilis, Fkbp6 and Prdm4, is observed from embryonic day (E) 3.25, and some of them, together with the late germ cell markers Zp3, Mcf2 and Morc1, become restricted to the EPI subpopulation at E4.5, while the dynamics analysis of the PE-EPI transitions in the single-cell data suggests that TCFAP2C transitorily represses Dnmt3l in EPI cells at E3.5 and such repression is withdrawn with reactivation of Dnmt3l expression in PE and EPI cells at E4.5.

WHAT IS KNOWN ALREADY

In the mouse preimplantation embryo, cells with the same phenotype take different fates based on the orchestration between topological clues (cell polarity, positional history and division orientation) and gene regulatory rules (at transcriptomics and epigenomics level), prompting the proposal of positional, stochastic and combined models explaining the specification mechanism. PGC specification starts at E6.0-6.5 post-implantation. In view of the important role of DNA methylation in developmental events, the cross-talk between some transcription factors and DNA methyltransferases is of particular relevance. TCFAP2C has a CpG DNA methylation motif that is not methylated in pluripotent cells and that could potentially bind on DNMT3L, the stimulatory DNA methyltransferase co-factor that assists in the process of de novo DNA methylation. Chromatin-immunoprecipitation analysis has demonstrated that Dnmt3l is indeed a target of TCFAP2C.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

We aimed to assess the timing of early preimplantation events and to understand better the segregation of the inner cell mass (ICM) into PE and EPI. We designed a single-cell transcriptomics dynamics computational study to identify markers of the PE-EPI bifurcation in ICM cells through searching for statistically significant (using the Student's t-test method) differently expressed genes (DEGs) between PE and EPI cells from E3.5 to E4.5. The DEGs common for E3.5 and E4.5 were used as the markers defining the steady states. We collected microarray and next-generation sequencing transcriptomics data from public databases from bulk populations and single cells from mice at E3.25, E3.5 and E4.5. The results are based on three independent single-cell transcriptomics data sets, with a fold change of 3 and P-value <0.01 for the DEG selection.

MAIN RESULTS AND THE ROLE OF CHANCE

The dynamics analysis revealed new transitory E3.5 and steady PE and EPI markers. Among the transitory E3.5 PE markers (Dnmt3l, Dusp4, Cpne8, Akap13, Dcaf12l1, Aaed1, B4galt6, BC100530, Rnpc3, Tfpi, Lgalsl, Ckap4 and Fbxl20), several (Dusp4, Akap13, Cpn8, Dcaf12l1 and Tfpi) are related to the extracellular regulated kinase pathway. We also identified new transitory E3.5 EPI markers (Sgk1, Mal, Ubxn2a, Atg16l2, Gm13102, Tcfap2c, Hexb, Slc1a1, Svip, Liph and Mier3), six new stable PE markers (Sdc4, Cpn1, Dkk1, Havcr1, F2r/Par1 and Slc7a6os) as well as three new stable EPI markers (Zp3, Mcf2 and Hexb), which are known to be late stage germ cell markers. We found that mouse PGC marker activation starts at least at E3.25 preimplantation. The transcriptomics dynamics analyses support the regulation of Dnmt3l expression by TCFAP2C.

LIMITATIONS, REASONS FOR CAUTION

Since the regulation of Dnmt3l by TCFAP2C is based on computational prediction of DNA methylation motifs, Chip-Seq and transcriptomics data, functional studies are required to validate this result.

WIDER IMPLICATIONS OF THE FINDINGS

We identified a collection of previously undescribed E3.5-specific PE and EPI markers, and new steady PE and EPI markers. Identification of these genes, many of which encode cell membrane proteins, will facilitate the isolation and characterization of early PE and EPI populations. Since it is so well established in the literature that mouse PGC specification is a post-implantation event, it was surprising for us to see activation of PGC markers as early as E3.25 preimplantation, and identify the newly found steady EPI markers as late germ cell markers. The discovery of such early activation of PGC markers has important implications in the derivation of germ cells from pluripotent cells (embryonic stem cells or induced pluripotent stem cells), since the initial stages of such derivation resemble early development. The early activation of PGC markers points out the difficulty of separating PGC cells from pluripotent populations. Collectively, our results suggest that the combining of the precision of single-cell omics data with dynamic analysis of time-series data can establish the timing of some developmental stages as earlier than previously thought.

LARGE-SCALE DATA

Not applicable.

STUDY FUNDING AND COMPETING INTERESTS

This work was supported by grants DFG15/14 and DFG15/020 from Diputación Foral de Gipuzkoa (Spain), and grant II14/00016 from I + D + I National Plan 2013-2016 (Spain) and FEDER funds. The authors declare no conflict of interest.

Zebrafish Germ Cell Tumors

Germ cell tumors (GCTs) are malignant cancers that arise from embryonic precursors known as Primordial Germ Cells. GCTs occur in neonates, children, adolescents and young adults and can occur in the testis, the ovary or extragonadal sites. Because GCTs arise from pluripotent cells, the tumors can exhibit a wide range of different histologies. Current cisplatin-based combination therapies cures most patients, however at the cost of significant toxicity to normal tissues. While GWAS studies and genomic analysis of human GCTs have uncovered somatic mutations and loci that might confer tumor susceptibility, little is still known about the exact mechanisms that drive tumor development, and animal models that faithfully recapitulate all the different GCT subtypes are lacking. Here, we summarize current understanding of germline development in humans and zebrafish, describe the biology of human germ cell tumors, and discuss progress and prospects for zebrafish GCT models that may contribute to better understanding of human GCTs.

Age-related onset of obesity corresponds with metabolic dysregulation and altered microglia morphology in mice deficient for Ifitm proteins

The IfitmDel mouse lacks all five of the Ifitm genes via LoxP deletion. This animal breeds normally with no obvious defect in development. The IfitmDel animals exhibit a steady and significantly enhanced weight gain relative to wild-type controls beginning about three months of age and under normal feeding conditions. The increased weight corresponds with elevated fat mass, and in tolerance tests they are hyporesponsive to insulin but respond normally to glucose. Both young (4 mo) and older (12 mo) IfitmDel mice have enhanced levels of serum leptin suggesting a defect in leptin/leptin receptor signaling. Analysis of the gene expression profiles in the hypothalamus of IfitmDel animals, compared to WT, demonstrated an altered ratio of Pomc and Npy neuropeptide expression, which likely impairs the satiation response of the IfitmDel animal leading to an increased eating behavior. Also elevated in hypothalamus of IfitmDel mice were pro-inflammatory cytokine expression and reduced IL-10. Anatomical analysis of the hypothalamus using immunohistochemistry revealed that microglia exhibit an abnormal morphology in IfitmDel animals and respond abnormally to Poly:IC challenge. These abnormalities extend the phenotype of the IfitmDel mouse beyond abnormal responses to viral challenge to include a metabolic phenotype and weight gain. Further, this novel phenotype for the IfitmDel mouse could be related to abnormal neuropeptide production, inflammatory status and microglia status in the hypothalamus.

Importance of interferon inducible trans-membrane proteins and retinoic acid inducible gene I for influenza virus replication: A review

Understanding the interplay between Influenza viruses and host cells is key to elucidating the pathogenesis of these viruses. Several host factors have been identified that exert antiviral functions; however, influenza viruses continue to replicate utilizing host cell machinery. Herein, we review the mechanisms of action of two host-derived proteins on conferring cellular resistance to the influenza virus; (1) the interferon inducible trans-membrane proteins, 1, 2 and 3, a recently identified family of early restriction factors; and (2) retinoic acid inducible gene I, a key mediator of antiviral immunity. These data may contribute to the design of novel and efficient anti-influenza treatments.

Stem cells derived from human first-trimester umbilical cord have the potential to differentiate into oocyte-like cells in vitro

Compared to stem cells derived from human term umbilical cord, stem cells derived from human first-trimester umbilical cord (hFTUC) exhibit a significantly greater proliferative potential, and more efficiency in terms of their in vitro differentiation. In the present study, we investigated whether hFTUC-derived stem cells are able to differentiate into germ cells. The hFTUC-derived stem cells were first isolated, expanded and then cultured in differentiation medium containing human follicular fluid, follicle-stimulating hormone (FSH)/luteinizing hormone (LH) and estradiol for 24 days. During the period of induction, a subpopulation of the cultured cells appeared that had a morphological resemblance to primordial germ cells (PGCs) and cumulus-oocyte complex (COC)-like cells, and oocyte-like cells (OLCs). The PGC-like cells expressed specific markers indicative of germ cell formation such as octamer-binding transcription factor 4 (OCT4), stage-specific embryonic antigen 1 (SSEA1), B lymphocyte-induced maturation protein-1 (BLIMP1), PR domain containing 14 (PRDM14), transcription factor AP-2 gamma (TFAP2C), VASA, STELLA, deleted in azoospermia-like (DAZL) and interferon-induced transmembrane protein 3 (IFITM3). The OLCs, which contained a single germinal vesicle, expressed oocyte-specific markers, such as synaptonemal complex protein 3 (SCP3), growth/differentiation factor-9 (GDF9), GDF9B and zona pellucida (ZP)1, ZP2 and ZP3. The COC-like cells secreted estradiol, vascular endothelial growth factor and leukemia inhibitory factor. Thus, our findings suggest that hFTUC-derived stem cells have an intrinsic ability to differentiate into OLCs, which may provide an in vitro model for the identification of factors involved in germ cell formation and differentiation.

Stem cells, progenitor cells, and lineage decisions in the ovary

Exploring stem cells in the mammalian ovary has unleashed a Pandora's box of new insights and questions. Recent evidence supports the existence of stem cells of a number of the different cell types within the ovary. The evidence for a stem cell model producing mural granulosa cells and cumulus cells is strong, despite a limited number of reports. The recent identification of a precursor granulosa cell, the gonadal ridge epithelial-like cell, is exciting and novel. The identification of female germline (oogonial) stem cells is still very new and is currently limited to just a few species. Their origins and physiological roles, if any, are unknown, and their potential to produce oocytes and contribute to follicle formation in vivo lacks robust evidence. The precursor of thecal cells remains elusive, and more compelling data are needed. Similarly, claims of very small embryonic-like cells are also preliminary. Surface epithelial cells originating from gonadal ridge epithelial-like cells and from the mesonephric epithelium at the hilum of the ovary have also been proposed. Another important issue is the role of the stroma in guiding the formation of the ovary, ovigerous cords, follicles, and surface epithelium. Immune cells may also play key roles in developmental patterning, given their critical roles in corpora lutea formation and regression. Thus, while the cellular biology of the ovary is extremely important for its major endocrine and fertility roles, there is much still to be discovered. This review draws together the current evidence and perspectives on this topic.

Cloning and characterization of ifitm1 and ifitm3 expression during early zebrafish development

The family of interferon-inducible transmembrane proteins (IFITMs) plays a crucial role in inhibiting proliferation, promoting homotypic cell adhesion and mediating germ cell development. In the present study, the full-length cDNAs of zebrafish ifitm1 (744 bp) and ifitm3 (702 bp) were obtained by rapid amplification of cDNA ends (RACE). Reverse transcription polymerase chain reaction (RT-PCR) analysis showed that ifitm1 mRNA was expressed in the ovary, testis, brain, muscle, liver and kidney, while ifitm3 mRNA was only detected in the ovary. Based on in situ hybridization, ifitm1 mRNA was found to be strongly expressed in the ooplasm from stage I to stage II and ifitm3 mRNA was also strongly expressed in the ooplasm from stage I to stage II, furthermore ifitm3 expression ultimately localized to the cortex region beneath the plasma membrane of stage IV oocytes. During development, ifitm1 expression was initially detected in the enveloping layer cells and deep layer cells of shield stage embryos. Then, throughout the segmentation phase (10.25-24 hours post-fertilization (hpf)), ifitm1 expression was mainly detected in the head, trunk and tail regions. Unlike ifitm1, ifitm3 expression was initially detected in sphere stage embryos and was then broadly expressed throughout the embryo from the 70% epiboly stage to 24 hpf. Interestingly, ifitm3 was also expressed in primordial germ cells (PGCs) from the bud stage to 24 hpf. This expression analysis indicates that zebrafish ifitm1 may play a critical role in early organogenesis and may perform immune or hematopoietic functions and ifitm3 might be necessary for PGC migration and the formation of female germ cells.

IFITM-Family Proteins: The Cell's First Line of Antiviral Defense

Animal cells use a wide variety of mechanisms to slow or prevent replication of viruses. These mechanisms are usually mediated by antiviral proteins whose expression and activities can be constitutive but are frequently amplified by interferon induction. Among these interferon-stimulated proteins, members of the IFITM (interferon-induced transmembrane) family are unique because they prevent infection before a virus can traverse the lipid bilayer of the cell. At least three human IFITM proteins-IFITM1, IFITM2, and IFITM3-have antiviral activities. These activities limit infection in cultured cells by many viruses, including dengue virus, Ebola virus, influenza A virus, severe acute respiratory syndrome coronavirus, and West Nile virus. Murine Ifitm3 controls influenza A virus infection in vivo, and polymorphisms in human IFITM3 correlate with the severity of both seasonal and highly pathogenic avian influenza virus. Here we review the discovery and characterization of the IFITM proteins, describe the spectrum of their antiviral activities, and discuss potential mechanisms underlying these effects.

Mouse primordial germ cells: a reappraisal

Current dogma is that mouse primordial germ cells (PGCs) segregate within the allantois, or source of the umbilical cord, and translocate to the gonads, differentiating there into sperm and eggs. In light of emerging data on the posterior embryonic-extraembryonic interface, and the poorly studied but vital fetal-umbilical connection, we have reviewed the past century of experiments on mammalian PGCs and their relation to the allantois. We demonstrate that, despite best efforts and valuable data on the pluripotent state, what is and is not a PGC in vivo is obscure. Furthermore, sufficient experimental evidence has yet to be provided either for an extragonadal origin of mammalian PGCs or for their segregation within the posterior region. Rather, most evidence points to an alternative hypothesis that PGCs in the mouse allantois are part of a stem/progenitor cell pool that exhibits all known PGC "markers" and that builds/reinforces the fetal-umbilical interface, common to amniotes. We conclude by suggesting experiments to distinguish the mammalian germ line from the soma.

Mechanism and biological significance of the overexpression of IFITM3 in gastric cancer

Interferon‑induced transmembrane protein 3 (IFITM3) has been recently identified as a potential molecular marker. IFITM3 has been reported to be upregulated in various human diseases, including colon and breast cancer, astrocytoma, as well as ulcerative colitis. However, the clinical significance and underlying mechanisms of IFITM3 dysregulated expression in gastric cancer (GC) remain to be determined. The present study aimed to evaluate the expression of IFITM3 in human gastric tumor cells and specimens and investigate the effects of IFITM3 knockdown in the regulation of GC growth and its potential mechanism. IFITM3 expression was significantly overexpressed in the GC cell lines and GC tissues compared with corresponding normal controls by RT‑qPCR, western blot analysis and immunohistochemistry, and this overexpression was correlated with tumor differentiation, lymph node and distant metastasis, and advanced tumor node metastasis stages. Furthermore, knockdown of IFITM3 expression suppressed tumor cell migration, invasion and proliferation significantly in vitro, arrested tumor cells at the G0/G1 phase and reduced the cell numbers in the S phase of the cell cycle. We preliminarily confirmed that IFITM3 can be mediated by the activities of Wnt/β-catenin signaling. Further investigation revealed that silencing of IFITM3 effectively reversed the epithelial-to-mesenchymal transition (EMT) phenotype and reduced the activities of MMP-2 and MMP-9 expression. Taken together, these data suggested that IFITM3 is a potential therapeutic target for GC.

Contemporary Approaches for Identifying Rare Bone Disease Causing Genes

Recent improvements in the speed and accuracy of DNA sequencing, together with increasingly sophisticated mathematical approaches for annotating gene networks, have revolutionized the field of human genetics and made these once time consuming approaches assessable to most investigators. In the field of bone research, a particularly active area of gene discovery has occurred in patients with rare bone disorders such as osteogenesis imperfecta (OI) that are caused by mutations in single genes. In this perspective, we highlight some of these technological advances and describe how they have been used to identify the genetic determinants underlying two previously unexplained cases of OI. The widespread availability of advanced methods for DNA sequencing and bioinformatics analysis can be expected to greatly facilitate identification of novel gene networks that normally function to control bone formation and maintenance.

The role of IFITM3 in the growth and migration of human glioma cells

BACKGROUND

Interferon induced transmembrane protein 3 (IFITM3) is transcribed in most tissues and highly interferon-inducible. However, the role of IFITM3 in cancer is still poorly understood.

METHODS

Expression levels of IFITM3 were analyzed in 60 glioma patients by immunohistochemistry (IHC). Following closely, we investigated the phenotype of IFITM3 knockdown on glioma cell growth and tumorigenesis in vitro using lentivirus-mediated loss-of-function strategy.

RESULTS

Depletion of IFITM3in U251 cells dramatically inhibited cell proliferation and colony formation, which demonstrated that reduced IFITM3 protein levels could cause inhibition of tumorigenesis. Knockdown of IFITM3 also induced cell cycle arrest in G0/G1 phase, especially in the sub-G1 phase representing apoptotic cells. In addition, the migration of U251 cells was visibly weakened after IFITM3 knockdown, as determined by Transwell assay.

CONCLUSIONS

Our findings provide new evidence that IFITM3 plays an important role in glioma cell growth and migration, suggesting that silencing of IFITM3 by RNA interference (RNAi) may be a potential approach to suppress glioma growth.

Defining the neighborhoods that escort the oocyte through its early life events and into a functional follicle

The ovary functions to chaperone the most precious cargo for female individuals, the oocyte, thereby allowing the passage of genetic material to subsequent generations. Within the ovary, single oocytes are surrounded by a legion of granulosa cells inside each follicle. These two cell types depend upon one another to support follicle formation and oocyte survival. The infrastructure and events that work together to ultimately form these functional follicles within the ovary are unprecedented, given that the oocyte originates as a cell like all other neighboring cells within the embryo prior to gastrulation. This review discusses the journey of the germ cell in the context of the developing female mouse embryo, with a focus on specific signaling events and cell-cell interactions that escort the primordial germ cell as it is specified into the germ cell fate, migrates through the hindgut into the gonad, differentiates into an oocyte, and culminates upon formation of the primordial and then primary follicle.

Identification of the polymorphisms in IFITM1 gene and their association in a Korean population with ulcerative colitis

Interferon inducible transmembrane protein (IFITM) family genes have been implicated in several cellular processes such as the homotypic cell adhesion functions of IFNs and cellular anti-proliferative activities. We previously showed that the IFITM3 single nucleotide polymorphisms (SNPs) associated with susceptibility to ulcerative colitis (UC). The present study aimed to investigate whether the polymorphisms in the IFITM1 gene are associated with susceptibility to UC. We also evaluated the expression levels in the putative functional promoter polymorphisms to determine the change of their activity. Gene expression profiles in the tissues obtained from human digestive tracts by RT-PCR, and the possible variation sites and SNPs of IFITM1 were identified by direct sequencing method. Genotype analysis in the IFITM1 SNPs was performed by high resolution melting and TaqMan probe analysis, and the haplotype frequencies of IFITM1 SNPs for multiple loci were estimated using the expectation maximization (EM) algorithm. The expression levels in the putative functional promoter polymorphisms were evaluated by performing a luciferase reporter assay. We identified two SNPs and two variation sites, g.-1920G>A (rs77537847), g.-1547delA (novel) and g.-416C>G (rs11246062) in the promoter region, and g.364delA (rs200576757) in intron 1. The genotype and allele frequencies of the g.-1920G>A polymorphism of IFITM1 gene in the UC patients were significantly different from those of the healthy controls (P=0.002 and 0.042, respectively). These results suggest that the g.-1920G>A polymorphism in IFITM1 may be associated with susceptibility to UC.