Computational design of transmembrane pores.

Transmembrane channels and pores have key roles in fundamental biological processes1 and in biotechnological applications such as DNA nanopore sequencing2-4, resulting in considerable interest in the design of pore-containing proteins. Synthetic amphiphilic peptides have been found to form ion channels5,6, and there have been recent advances in de novo membrane protein design7,8 and in redesigning naturally occurring channel-containing proteins9,10. However, the de novo design of stable, well-defined transmembrane protein pores that are capable of conducting ions selectively or are large enough to enable the passage of small-molecule fluorophores remains an outstanding challenge11,12. Here we report the computational design of protein pores formed by two concentric rings of α-helices that are stable and monodisperse in both their water-soluble and their transmembrane forms. Crystal structures of the water-soluble forms of a 12-helical pore and a 16-helical pore closely match the computational design models. Patch-clamp electrophysiology experiments show that, when expressed in insect cells, the transmembrane form of the 12-helix pore enables the passage of ions across the membrane with high selectivity for potassium over sodium; ion passage is blocked by specific chemical modification at the pore entrance. When incorporated into liposomes using in vitro protein synthesis, the transmembrane form of the 16-helix pore-but not the 12-helix pore-enables the passage of biotinylated Alexa Fluor 488. A cryo-electron microscopy structure of the 16-helix transmembrane pore closely matches the design model. The ability to produce structurally and functionally well-defined transmembrane pores opens the door to the creation of designer channels and pores for a wide variety of applications.

Zonular instability-associated morphologic features in eyes with primary angle closure disease using the swept-source anterior segment - optical coherence tomography system.

BACKGROUND: This study aims to investigate the morphologic features of the crystalline lens in Primary Angle Closure Disease (PACD) patients with zonular instability during cataract surgery using the swept-source CASIA 2 Anterior Segment-Optical Coherence Tomography (AS-OCT) system. METHODS: A total of 398 eyes (125 PACD eyes with zonular instability, 133 PACD eyes with zonular stability, and 140 cataract patient controls) of 398 patients who underwent cataract surgery combined or not glaucoma surgery between January 2021 and January 2023 were enrolled. The crystalline lens parameters were measured by CASIA2 AS-OCT. Then, logistic regression was performed to evaluate the risk factors associated with zonular instability. RESULTS: The results revealed that PACD eyes had a more anterior lens equator position, a steeper anterior curvature of lens, shorter Axial Length (AL), shallower Anterior Chamber Distance (ACD), higher Lens Vault (LV) and thicker Lens Thickness (LT), when compared to eyes in the cataract control group. Furthermore, PACD eyes in the zonular instability group had steeper front R, front Rs and Front Rf, flatter back Rf, thicker lens anterior part thickness, higher lens anterior-to-posterior part thickness ratios, shallower ACD, and greater LV, when compared to PACD eyes with zonular stability. The logistic regression analysis, which was adjusted for age and gender, revealed that zonular instability was positively correlated with anterior part thickness, lens anterior-to-posterior part thickness ratio, and LV, but was negatively correlated with lens anterior radius and ACD. CONCLUSION: Steeper anterior curvature, increased lens anterior part thickness, higher anterior-to-posterior part thickness ratio, shallower ACD, and greater LV are the anatomic features of PACD eyes associated with zonular instability.

Genome Resource of Streptomyces atratus PY-1, a Broad-Spectrum Antimicrobial Strain in Particular Antagonistic Against Plasmopara viticola.

Streptomyces atratus PY-1 exhibited promising antimicrobial properties; in particular, it is highly inhibitory to Plasmopara viticola, which causes downy mildew of grape. It is very necessary to carry out systematic and in-depth research on the PY-1 strain for the improvement, application, and promotion of biocontrol agents. The PY-1 genome was fully sequenced and assembled. We present the draft genome sequence of PY-1, with a size of 9, 254, and 781 bp. Preliminary analysis on the PY-1 genome sequence shows that at least 35 gene clusters are involved in the biosynthesis of polyketides, terpenes, and nonribosomally synthesized peptides.

Overexpression of the First Peanut-Susceptible Gene, AhS5H1 or AhS5H2, Enhanced Susceptibility to Pst DC3000 in Arabidopsis.

Salicylic acid (SA) serves as a pivotal plant hormone involved in regulating plant defense mechanisms against biotic stresses, but the extent of its biological significance in relation to peanut resistance is currently lacking. This study elucidated the involvement of salicylic acid (SA) in conferring broad-spectrum disease resistance in peanuts through the experimental approach of inoculating SA-treated leaves. In several other plants, the salicylate hydroxylase genes are the typical susceptible genes (S genes). Here, we characterized two SA hydroxylase genes (AhS5H1 and AhS5H2) as the first S genes in peanut. Recombinant AhS5H proteins catalyzed SA in vitro, and showed SA 5-ydroxylase (S5H) activity. Overexpression of AhS5H1 or AhS5H2 decreased SA content and increased 2,5-DHBA levels in Arabidopsis, suggesting that both enzymes had a similar role in planta. Moreover, overexpression of each AhS5H gene increased susceptibility to Pst DC3000. Analysis of the transcript levels of defense-related genes indicated that the expression of AhS5H genes, AhNPR1 and AhPR10 was simultaneously induced by chitin. Overexpression of each AhS5H in Arabidopsis abolished the induction of AtPR1 or AtPR2 upon chitin treatment. Eventually, AhS5H2 expression levels were highly correlated with SA content in different tissues of peanut. Hence, the expression of AhS5H1 and AhS5H2 was tissue-specific.

TSAd Plays a Major Role in Myo9b-Mediated Suppression of Malignant Pleural Effusion by Regulating TH1/TH17 Cell Response.

Emerging evidence indicates that Myo9b is a cancer metastasis-related protein and functions in a variety of immune-related diseases. However, it is not clear whether and how Myo9b functions in malignant pleural effusion (MPE). In this study, our data showed that Myo9b expression levels correlated with lung cancer pleural metastasis, and nucleated cells in MPE from either patients or mice expressed a lower level of Myo9b than those in the corresponding blood. Myo9b deficiency in cancer cells suppressed MPE development via inhibition of migration. Myo9b deficiency in mice suppressed MPE development by decreasing TH1 cells and increasing TH17 cells. CD4+ naive T cells isolated from Myo9b-/- mouse spleens exhibited less TH1 cell differentiation and more TH17 cell differentiation in vitro. mRNA sequencing of nucleated cells showed that T cell-specific adaptor protein (TSAd) was downregulated in Myo9b-/- mouse MPE, and enrichment of the H3K27me3 mark in the TSAd promoter region was found in the Myo9b-/- group. Naive T cells purified from wild type mouse spleens transfected with TSAd-specific small interfering RNAs (siRNAs) also showed less TH1 cell differentiation and more TH17 cell differentiation than those from the siRNA control group. Furthermore, downregulation of TSAd in mice using cholesterol-conjugated TSAd-specific siRNA suppressed MPE development, decreased TH1 cells, and increased TH17 cells in MPE in vivo. Taken together, Myo9b deficiency suppresses MPE development not only by suppressing pleural cancer metastasis but also by regulating TH1/TH17 cell response via a TSAd-dependent pathway. This work suggests Myo9b and TSAd as novel candidates for future basic and clinical investigations of cancer.

IL-10 promotes malignant pleural effusion in mice by regulating TH 1- and TH 17-cell differentiation and migration.

The role of IL-10 in malignant pleural effusion (MPE) remains unknown. By using murine MPE models, we observed that an increase in pleural IL-10 was a significant predictor of increased risk of death. We noted that TH 1- and TH 17-cell content in MPE was higher in IL-10-/- mice than in WT mice, and IL-10 deficiency promoted differentiation into TH 1 but not into TH 17 cells. A higher fraction of TH 1 and TH 17 cells in the MPE of IL-10-/- mice expressed CXCR3 compared with WT mice. We also demonstrated that Lewis lung cancer and colon adenocarcinoma cells secreted large amounts of CXCL10, a ligand of CXCR3, which induced the migration of TH 1 and TH 17 cells into the MPE, and IFN-γ could promote this signaling cascade. Furthermore, intrapleural injection of mice with CXCL10-deficient tumor cells led to decreased TH 1- and TH 17-cell content in MPE, increased MPE volume, and reduced survival of MPE-bearing mice. Taken together, we demonstrated that IL-10 deficiency promoted T-cell differentiation into TH 1 cells and upregulated the CXCR3-CXCL10 signaling pathway that recruits TH 1 and TH 17 cells into MPE, ultimately resulting in decreased MPE formation and longer survival time of mice-bearing MPE.

Evaporation Enhancement of Microscale Droplet Impact on Micro/Nanostructured Surfaces.

The vicinity of the droplet three-phase contact line can be divided into four regions depending on the dominant forces and the liquid film thickness: the absorbed film region, the transition region, the intrinsic meniscus region, and the microconvection region, wherein the transition region has the largest evaporation rate for smaller thermal resistance and weaker intermolecular force between the liquid-vapor interface and the solid surface. On the basis of this perception, micro/nanostructured surfaces (ZnO nanowire surface (ZnO-NW) and copper inverse opal surface (CIO)) were fabricated to enhance the droplet evaporation rate. The precursor film, which can be regarded as the greatly enlarged transition region, was observed on the structured surfaces and promoted the droplet evaporation rate dramatically. The mechanisms of the formation and evolution of the precursor film were studied. Moreover, the second fast spreading of the droplet resulting from vigorous boiling on the structured surfaces enhanced the heat transfer between the droplet and the surface and also promoted the Leidenfrost temperature of the impact droplet.

Interplay between the catabolite repression control protein Crc, Hfq and RNA in Hfq-dependent translational regulation in Pseudomonas aeruginosa.

In Pseudomonas aeruginosa the RNA chaperone Hfq and the catabolite repression control protein (Crc) act as post-transcriptional regulators during carbon catabolite repression (CCR). In this regard Crc is required for full-fledged Hfq-mediated translational repression of catabolic genes. RNAseq based transcriptome analyses revealed a significant overlap between the Crc and Hfq regulons, which in conjunction with genetic data supported a concerted action of both proteins. Biochemical and biophysical approaches further suggest that Crc and Hfq form an assembly in the presence of RNAs containing A-rich motifs, and that Crc interacts with both, Hfq and RNA. Through these interactions, Crc enhances the stability of Hfq/Crc/RNA complexes, which can explain its facilitating role in Hfq-mediated translational repression. Hence, these studies revealed for the first time insights into how an interacting protein can modulate Hfq function. Moreover, Crc is shown to interfere with binding of a regulatory RNA to Hfq, which bears implications for riboregulation. These results are discussed in terms of a working model, wherein Crc prioritizes the function of Hfq toward utilization of favored carbon sources.

IL-17A-Producing γδT Cells Inhibit the Formation of Malignant Pleural Effusions.

γδT cells are an important source of IL-17A and play an anti- or protumor role depending on the surrounding microenvironment. The precise role of γδT cells in the development of malignant pleural effusions (MPE) remains unknown. Using flow cytometry, we analyzed the distribution and differentiation of γδT cells in wild-type (WT) and IL-10-∕- mice. We carefully elucidated the influence of γδT cells on the formation of MPE by depleting γδT cells from WT, IL-10-∕-, and IL-17a-∕- mice. The distribution of γδT17 cells in human MPE and peripheral blood was also determined. Our data showed that both γδT cells and IL-17A-producing γδT (γδT17) cells accumulated in murine MPE, and IL-10 deficiency enhanced their accumulation. γδT cells were the main source of IL-17A in MPE for both WT and IL-10-∕- mice. IL-10 inhibited the chemotactic response of γδT cells to MPE and the proliferation of these cells. IL-10 suppressed γδT cell secretion of IL-17A via RORγt. The ablation of γδT cells accelerated MPE accumulation in both WT and IL-10-∕- mice, but it did not influence MPE accumulation in IL-17a-∕- mice. Patients with higher frequencies of γδT17 cells had significantly longer survival times than patients with lower frequencies of γδT17 cells. Taken together, our data demonstrate that γδT17 cells play an inhibitory role in the progression of MPE, and the accumulation of γδT17 cells in MPE is suppressed by IL-10.

Testis-specific protein, Y-linked 1 activates PI3K/AKT and RAS signaling pathways through suppressing IGFBP3 expression during tumor progression.

The testis-specific protein, Y-linked 1 (TSPY1), a newly recognized cancer/testis antigen, has been suggested to accelerate tumor progression. However, the mechanisms underlying TSPY1 cancer-related function remain limited. By mining the RNA sequencing data of lung and liver tumors from The Cancer Genome Atlas, we found frequent ectopic expression of TSPY1 in lung adenocarcinoma (LUAD) and liver hepatocellular carcinoma (LIHC), and the male-specific protein was associated with higher mortality rate and worse overall survival in patients with LUAD and LIHC. Overexpression of TSPY1 promotes cell proliferation, invasiveness, and cycle transition and inhibits apoptosis, whereas TSPY1 knockdown has the opposite effects on these cancer cell phenotypes. Transcriptomic analysis revealed the involvement of TSPY1 in PI3K/AKT and RAS signaling pathways in both LUAD and LIHC cells, which was further confirmed by the increase in the levels of phosphorylated proteins in the PI3K-AKT and RAS signaling pathways in TSPY1-overexpressing cancer cells, and by the suppression on the activity of these two pathways in TSPY1-knockdown cells. Further investigation identified that TSPY1 could directly bind to the promoter of insulin growth factor binding protein 3 (IGFBP3) to inhibit IGFBP3 expression and that downregulation of IGFBP3 increased the activity of PI3K/AKT/mTOR/BCL2 and RAS/RAF/MEK/ERK/JUN signaling in LUAD and LIHC cells. Taken together, the observations reveal a novel mechanism by which TSPY1 could contribute to the progression of LUAD and LIHC. Our finding is of importance for evaluating the potential of TSPY1 in immunotherapy of male tumor patients with TSPY1 expression.

DNA demethylation facilitates the specific transcription of the mouse X-linked Tsga8 gene in round spermatids†.

Some X-linked genes necessary for spermiogenesis are specifically activated in the postmeiotic germ cells. However, the regulatory mechanism about this activation is not clearly understood. Here, we examined the potential mechanism controlling the transcriptional activation of the mouse testis specific gene A8 (Tsga8) gene in round spermatids. We observed that the Tsga8 expression was negatively correlated with the methylation level of the CpG sites in its core promoter. During spermatogenesis, the Tsga8 promoter was methylated in spermatogonia, and then demethylated in spermatocytes. The demethylation status of Tsga8 promoter was maintained through the postmeiotic germ cells, providing a potentially active chromatin for Tsga8 transcription. In vitro investigation showed that the E12 and Spz1 transcription factors can enhance the Tsga8 promoter activity by binding to the unmethylated E-box motif within the Tsga8 promoter. Additionally, the core Tsga8 promoter drove green fluorescent protein (GFP) expression in the germ cells of Tsga8-GFP transgenic mice, and the GFP expression pattern was similar to that of endogenous Tsga8. Moreover, the DNA methylation profile of the Tsga8-promoter-driven transgene was consistent with that of the endogenous Tsga8 promoter, indicating the existence of a similar epigenetic modification for the Tsga8 promoter to ensure its spatiotemporal expression in vivo. Taken together, this study reports the details of a regulatory mechanism that includes DNA methylation and transcription factors to mediate the postmeiotic expression of an X-linked gene.

Exonuclease I and III improve the detection efficacy of hepatitis B virus covalently closed circular DNA.

BACKGROUND: Hepatitis B virus covalently closed circular DNA (HBV cccDNA) is an important biomarker of hepatitis B virus infection. However, the current methods are not specific and sensitive. The present study aimed to develop a specific and sensitive assay method for the quantification of HBV cccDNA. METHODS: Exonuclease I (Exo I) & Exonuclease III (Exo III) and specific primer probes are used in real-time PCR. The virus particles isolated from peripheral blood mononuclear cells were used as negative control and HBV1.3 recombinant plasmid 3.2 kb circular DNA fragment was used as positive control. The methods of cccDNA detection were evaluated in cell lines, plasmid, animal model, patient serum and liver biopsies. RESULTS: A linear range of 101-107 copies/assay using specific primers for HBV cccDNA was established. HBV cccDNA were only detected in cell lines, animal model and liver tissue. It cannot be detected in serum samples. Intrahepatic HBV cccDNA level had good correlation with intrahepatic total HBV DNA level (r = 0.765, P < 0.001). CONCLUSIONS: The real-time quantitative PCR is an effective and feasible method for sensitive and specific detection of low copy number of cccDNA. The novel detection method is fast, provides high sensitivity and specificity and can be used in clinical practice.

[Reflection of a case misdiagnosed as trisomy 21 syndrome by G-banded chromosomal karyotyping analysis].

OBJECTIVE: To emphasize the clinical significance of copy number variations (CNVs) detection by describing a case misdiagnosed as trisomy 21 syndrome by G-banded chromosomal karyotype analysis. METHODS: A girl with obesity and short stature was diagnosed as trisomy 21 syndrome by G-banded chromosomal karyotype analysis. Considering the discrepancy of her karyotype with her phenotype, genomic CNVs was detected by next-generation sequencing and the result was verified by quantitative PCR (qPCR). RESULTS: A microduplication of 16p11.2: 29 642 339-29 775 631 (133.292 kb) was detected. qPCR assay for QPRT and SPN located in the duplicated region confirmed the finding of CNVs assay. Meanwhile, her parents did not present similar duplication in 16p11.2. CONCLUSION: The 16p11.2 microduplication was a novel genomic structural variation in the girl, though it may not be associated with her clinical manifestations. Chromosomal microarray or next-generation sequencing-based CNVs detection can accurately determine the origin of small supernumerary marker chromosome and reduce the chance of misdiagnosis.

Activated naïve B cells promote development of malignant pleural effusion by differential regulation of TH1 and TH17 response.

Inflammatory signaling networks between tumor cells and immune cells contribute to the development of malignant pleural effusion (MPE). B cells have been found in MPE; however, little is known about their roles there. In the present study, by using mouse MPE models, we noted that although the total B cells in MPE were decreased as compared with the corresponding blood and spleen, the percentage of activated naïve B cells expressing higher levels of CD80, CD86, myosin heavy chain-II, CD44, CD69, and programmed cell death-ligand 1 (PD-L1) molecules were increased in wild-type mouse MPE. Compared with wild-type mice, decreased T helper (TH)1 cells and increased TH17 cells were present in B cell-deficient mouse MPE, which paralleled to the reduced MPE volume and longer survival time. Adoptive transfer of activated naïve B cells into B cell-deficient mice was able to increase TH1 cells and decrease TH17 cells in MPE and shorten the survival of mice bearing MPE. Furthermore, we demonstrated that activated naïve B cells inhibited TH17-cell expansion via the PD-1/PD-L1 pathway and promoted naïve CD4+ T-cell differentiation into TH1/TH17 cells through secreting IL-27/IL-6 independent of the PD-1/PD-L1 pathway. Collectively, our data uncovered a mechanism by which naïve B cells promote MPE formation by regulating TH1/TH17 cell responses, making these B cells an attractive target for therapeutic intervention in the fight against cancer.

Adipose mesenchymal stem cell-derived exosomes stimulated by hydrogen peroxide enhanced skin flap recovery in ischemia-reperfusion injury.

BACKGROUND: Mesenchymal stem cell (MSC)-derived exosomes have been recognized as new candidates for the treatment of ischemic disease or injury and may be an alternative treatment for cell therapy. This aim of the study was to evaluate whether exosomes derived from adipose mesenchymal stem cell (ADSC) can protect the skin flap during ischemia-reperfusion (I/R) injury and induce neovascularization. METHODS: To investigate the effects of exosomes in the I/R injury of flap transplantation in vivo, flaps were subjected to 6 h of ischemia by ligating the left superficial inferior epigastric vessels (SIEA) followed by blood perfusion. Exosomes derived from normal ADSC (ADSC-exos) and exosomes derived from ADSC preconditioned with H2O2 (H2O2-ADSC-exos) were injected into the flaps. Then, the blood perfusion unit (BPU) of the flaps was measured by Laser Doppler Perfusion Imaging (LDPI) and microvessel density was determined by the endothelial with cell marker CD31 with Immunohistochemistry (IHC) staining. Inflammatory cell infiltration of the skin flap and apoptosis were detected by hematoxylin & eosin staining (H&E) and the TdT-mediated biotinylated dUTP nick end-labeling (TUNEL) technique. RESULTS: In vivo, exosomes significantly increased flap survival and capillary density compared to I/R on postoperative day 5, and decreased the inflammatory reaction and apoptosis in the skin flap (P < 0.05). Furthermore, H2O2-ADSC-exos had better outcomes compared to normal exosomes (P < 0.05). ADSC-exos could significantly increase human umbilical vein endothelial cell (HUVEC) proliferation (P < 0.05), but no statistic difference was found in exosomes derived from different microenvironments (P > 0.05). HUVEC co-cultured with H2O2-ADSC-exos increased the migration ratio and generated more cord-like structures compared to ADSC-exos and the control group (P < 0.05). CONCLUSION: ADSC-exos can enhance skin flap survival, promote neovascularization and alleviate the inflammation reaction and apoptosis in the skin flap after I/R injury. The use of a specific microenvironment for in vitro stem cell culture, such as one containing a low concentration of H2O2, will facilitate the development of customized exosomes for cell-free therapeutic applications in skin flap transplantation.

Co-transplantation of exosomes derived from hypoxia-preconditioned adipose mesenchymal stem cells promotes neovascularization and graft survival in fat grafting.

BACKGROUND: Adipose-derived stromal cells (ADSCs)-derived exosomes (ADSC-Exos) account for the proangiogenic potential of stem cell. This study aimed to investigate the effect of ADSC-derived exosomes (ADSC-Exos) on the survival in fat grafting. METHODS: A nude mouse model of subcutaneous fat grafting was adopted. Hypoxic preconditioned ADSC-Exos and ADSC-Exos were injected around the grafted tissue. The fat graft sample was weighed and examined by hematoxylin and eosin (H&E) staining and immunohistochemistry. Laser Doppler flowmetry and CD31 immunofluorescence staining were used to analyze neovascularization. RESULTS: ADSC-Exo and hypoxic ADSC-Exo groups had a significantly higher weight of fat graft and more perilipin-positive adipocytes than the control groups from 2 to 8 weeks after grafting, and the hypoxic ADSC-Exo group had better outcomes (all P < 0.05). H&E staining showed that ADSC-Exos attenuated infiltration of inflammatory cells around the fat grafts. Laser Doppler flowmetry showed that the two ADSC-Exo groups had better blood perfusion in the graft tissue than the control groups (all P < 0.05). Immunofluorescence demonstrated that the hypoxic ADSC-Exo group had significantly more CD31-positive cells than the ADSC-Exo group. In vitro study showed that hypoxic ADSC-Exos treatment significantly increased the migration (at 12 and 24 h) and in vitro capillary network formation (at 12 h) in the human umbilical vein endothelial cells (HUVECs) as compared with the ADSC-Exo group and control group (all P < 0.05). CONCLUSIONS: Co-transplantation of ADSC-Exos can effectively promote the survival of graft, neovascularization and attenuated inflammation in the fat grafts. Hypoxia treatment can further enhance the beneficial effect of ADSC-Exos.

The unique GH5 cellulase member in the extreme halotolerant fungus Aspergillus glaucus CCHA is an endoglucanase with multiple tolerance to salt, alkali and heat: prospects for straw degradation applications.

In a halotolerant fungus Aspergillus glaucus CCHA, several functional proteins with stress-tolerant activity have been studied, but no secretory enzymes have been identified yet. The unique GH5 cellulase candidate from A. glaucus, an endoglucanase termed as AgCMCase, was cloned, expressed in the Pichia pastoris system and the purified enzyme was characterized. A large amount of recombinant enzyme secreted by the P. pastoris GS115 strain was purified to homogeneity. The molecular weight of the purified endoglucanase is about 55.0 kDa. The AgCMCase exhibited optimum catalytic activity at pH 5.0 and 55 °C. However, it remained relatively stable at temperatures ranging from 45 to 80 °C and pH ranging from 4.0 to 9.0. In addition, it showed higher activity at extreme NaCl concentrations from 1.0 to 4.0 M, suggesting it is an enzyme highly stable under heat, acid, alkaline and saline conditions. To evaluate the catalytic activity of AgCMCase, the hydrolysis products of rice and corn straws were successfully studied. In conclusion, the AgCMCase is a thermostable and salt-tolerant cellulase with potential for industrial application.

Spermatogenic phenotype of testis-specific protein, Y-encoded, 1 (TSPY1) dosage deficiency is independent of variations in TSPY-like 1 (TSPYL1) and TSPY-like 5 (TSPYL5): a case-control study in a Han Chinese population.

Testis-specific protein, Y-encoded, 1 (TSPY1) is involved in the regulation of spermatogenic efficiency via highly variable copy dosage, with dosage deficiency of the multicopy gene conferring an increased risk of spermatogenic failure. TSPY-like 1 (TSPYL1) and TSPY-like 5 (TSPYL5), two autosomal homologous genes originating from TSPY1, share a core sequence that encodes a functional nucleosome assembly protein (NAP) domain with TSPY1. To explore the potential effects of TSPYL1 and TSPYL5 on the TSPY1-related spermatogenic phenotype, we investigated the expression of these genes in 15 healthy and nonpathological human tissues (brain, kidney, liver, pancreas, thymus, prostate, spleen, muscle, leucocytes, placenta, intestine, ovary, lung, colon and testis) and explored associations between their variations and spermatogenic failure in 1558 Han Chinese men with different spermatogenic conditions, including 304 men with TSPY1 dosage deficiency. TSPYL1 and TSPYL5 were expressed in many different tissues, including the testis. An unreported rare variant that is likely pathogenic (c.1057A>G, p.Thr353Ala) and another of uncertain significance (c.1258C>T, p.Arg420Cys) in the NAP-coding sequence of TSPYL1 were observed in three spermatogenesis-impaired patients with heterozygous status. The distribution differences in the alleles, genotypes and haplotypes of eight TSPYL1- and TSPYL5-linked common variants did not reach statistical significance in comparisons of patients with spermatogenic failure and controls with normozoospermia. No difference in sperm production was observed among men with different genotypes of the variants. Similar results were obtained in men with TSPY1 dosage deficiencies. Although the distribution of missense variants of TSPYL1 found in the present and other studies suggests that patients with spermatogenic failure may have a statistically significant greater burden of rare variations in TSPYL1 relative to normozoospermic controls, the functional evidence suggests that TSPYL1 contributes to impaired spermatogenesis. Moreover, the present study suggests that the effects of TSPYL1 and TSPYL5 on the spermatogenic phenotype of TSPY1 dosage deficiency are limited, which may be due to the stability of their function resulting from high sequence conservation.

Linkage of catalysis and 5' end recognition in ribonuclease RNase J.

In diverse bacterial species, the turnover and processing of many RNAs is mediated by the ribonuclease RNase J, a member of the widely occurring metallo-ß-lactamase enzyme family. We present crystal structures of Streptomyces coelicolor RNase J with bound RNA in pre- and post-cleavage states, at 2.27 Å and 2.80 Å resolution, respectively. These structures reveal snapshots of the enzyme cleaving substrate directionally and sequentially from the 5' terminus. In the pre-cleavage state, a water molecule is coordinated to a zinc ion pair in the active site but is imperfectly oriented to launch a nucleophilic attack on the phosphate backbone. A conformational switch is envisaged that enables the in-line positioning of the attacking water and may be facilitated by magnesium ions. Adjacent to the scissile bond, four bases are stacked in a tightly sandwiching pocket, and mutagenesis results indicate that this organization helps to drive processive exo-ribonucleolytic cleavage. Like its numerous homologues, S. coelicolor RNase J can also cleave some RNA internally, and the structural data suggest how the preference for exo- versus endo-cleavage mode is linked with recognition of the chemical status of the substrate's 5' end.

MicroRNA-125b attenuates epithelial-mesenchymal transitions and targets stem-like liver cancer cells through small mothers against decapentaplegic 2 and 4.

UNLABELLED: Emerging evidence suggests that epithelial-mesenchymal transitions (EMTs) play important roles in tumor metastasis and recurrence. Understanding molecular mechanisms that regulate the EMT process is crucial for improving treatment of hepatocellular carcinoma (HCC). MicroRNAs (miRNAs) play important roles in HCC; however, the mechanisms by which miRNAs target the EMT and their therapeutic potential remains largely unknown. To better explore the roles of miRNAs in the EMT process, we established an EMT model in HCC cells by transforming growth factor beta 1 treatment and found that several tumor-related miRNAs were significantly decreased. Among these miRNAs, miR-125b expression was most strongly suppressed. We also found down-regulation of miR-125b in most HCC cells and clinical specimens, which correlated with cellular differentiation in HCC patients. We then demonstrated that miR-125b overexpression attenuated EMT phenotype in HCC cancer cells, whereas knockdown of miR-125b promoted the EMT phenotype in vitro and in vivo. Moreover, we found that miR-125b attenuated EMT-associated traits, including chemoresistance, migration, and stemness in HCC cells, and negatively correlated with EMT and cancer stem cell (CSC) marker expressions in HCC specimens. miR-125b overexpression could inhibit CSC generation and decrease tumor incidence in the mouse xenograft model. Mechanistically, our data revealed that miR-125b suppressed EMT and EMT-associated traits of HCC cells by targeting small mothers against decapentaplegic (SMAD)2 and 4. Most important, the therapeutic delivery of synthetic miR-125b mimics decreased the target molecule of CSC and inhibited metastasis in the mice model. These findings suggest a potential therapeutic treatment of miR-125b for liver cancer. CONCLUSION: miR-125b exerts inhibitory effects on EMT and EMT-associated traits in HCC by SMAD2 and 4. Ectopic expression of miR-125b provides a promising strategy to treat HCC.