Co-clustering of EphB6 and ephrinB1 in trans restrains cancer cell invasion

EphB6 is an understudied ephrin receptor tyrosine pseudokinase that is downregulated in multiple types of metastatic cancers. Unlike its kinase-active counterparts which autophosphorylate and transmit signals upon intercellular interaction, little is known about how EphB6 functions in the absence of intrinsic kinase activity. Here, we unveil a molecular mechanism of cell-cell interaction driven by EphB6. We identify ephrinB1 as a cognate ligand of EphB6 and show that in trans interaction of EphB6 with ephrinB1 on neighboring cells leads to the formation of large co-clusters at the plasma membrane. These co-clusters exhibit a decreased propensity towards endocytosis, suggesting a unique characteristic for this type of cell-cell interaction. Using lattice light-sheet microscopy, 3D structured illumination microscopy and cryo-electron tomography techniques, we show that co-clustering of EphB6 and ephrinB1 promotes the formation of double-membrane tubular structures between cells. Importantly, we also demonstrate that these intercellular structures stabilize cell-cell adhesion, leading to a reduction in the invasive behavior of cancer cells. Our findings rationalize a role for EphB6 pseudokinase as a tumor suppressor when interacting with its ligands in trans.

Structural mapping of PEAK pseudokinase interactions identifies 14-3-3 as a molecular switch for PEAK3 signaling

PEAK pseudokinases regulate cell migration, invasion and proliferation by recruiting key signaling proteins to the cytoskeleton. Despite lacking catalytic activity, alteration in their expression level is associated with several aggressive cancers. Here, we elucidate the molecular details of key PEAK signaling interactions with the adapter proteins CrkII and Grb2 and the scaffold protein 14-3-3. Our findings rationalize why the dimerization of PEAK proteins has a crucial function in signal transduction and provide biophysical and structural data to unravel binding specificity within the PEAK interactome. We identify a conserved high affinity 14-3-3 motif on PEAK3 and demonstrate its role as a molecular switch to regulate CrkII binding and signaling via Grb2. Together, our studies provide a detailed structural snapshot of PEAK interaction networks and further elucidate how PEAK proteins, especially PEAK3, act as dynamic scaffolds that exploit adapter proteins to control signal transduction in cell growth/motility and cancer.

[Efficacy of a recombinant bovine basic fibroblast growth factor gel for the treatment of moderate dry eye: a multicenter randomized double-blind parallel controlled clinical trial]

Objective: To compare the clinical efficacy of a recombinant bovine basic fibroblast growth factor (rb-bFGF) gel and a gel matrix in the treatment of moderate dry eye. Methods: It was a prospective random double-blind controlled study. One hundred patients diagnosed as moderate dry eye in Eye Institute and Affiliated Xiamen Eye Center of Xiamen University, Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology, Beijing Tongren Hospital, Capital Medical University, Eye & ENT Hospital of Fudan University and Zhongshan Ophthalmic Center from August 2015 to April 2019 were divided into two groups: experimental group and control group. Two groups of patients were allocated to receive either a rb-bFGF gel or a gel matrix 4 times per day for 4 weeks. Subjective symptoms, break-up time of the tear film (BUT), Schirmer Ⅰ test (SⅠt) and corneal fluorescein sodium staining were assessed at baseline, 2 and 4 weeks after treatment. Bulbar impression cytology was evaluated at baseline and 4 weeks after treatment. Irritation of the rb-bFGF gel and the gel matrix was estimated after treatment. T test, Wilcoxon signed-rank test or Mann-Whitney U test was used for quantitative data, and Chi-square test was used for enumerative data. Results: Eighty-four subjects were included for statistical analyses after the exclusion of 16 subjects who were lost for followup, with an age of 43±14 years. There were 42 cases in the experimental group and the control group, respectively. There was no statistically significant difference between the two groups in demographic baseline characteristics before treatment (P>0.05). The total score of subjective symptoms was 7.17±3.60 and 5.95±3.25 at 2 and 4 weeks after therapy in the experimental group, which were lower than 9.48±3.88 before treatment (t=6.226, 6.563; both P<0.05); in the control group, it was 7.01±3.25 and 6.32±3.85 at 2 and 4 weeks after treatment, with a significant reduction in comparison with that before treatment (9.15±3.58; t=4.693, 4.726; both P<0.05). The median (lower quartile, upper quartile) BUT was 4.00 (2.40, 5.00) s and 4.64 (3.00, 5.00) s at 2 and 4 weeks after therapy in the experimental group, which were longer than 3.72 (2.00, 4.39) s before treatment (Z=-2.485, -3.152; both P<0.05). The BUT was 4.41 (2.79, 5.12) s at 2 weeks after therapy in the control group, which was of no statistical difference compared with 3.89 (2.09, 4.25) s before treatment (Z=-1.953, P>0.05). The BUT was 5.21 (3.00, 5.02) s at 4 weeks after therapy in the control group, which was longer than that before treatment (Z=-2.485, P<0.05). The SⅠt score was 7.31 (3.75, 10.00) mm and 8.50 (4.00, 11.00) mm at 2 and 4 weeks after therapy in the experimental group, which were significantly higher than 6.69 (2.00, 8.13) mm before treatment (Z=-2.031, -2.236; both P<0.05); in the control group, it was 6.82 (2.00, 8.25) mm and 6.86 (3.00, 9.25) mm at 2 and 4 weeks after therapy, which were not significantly increased compared with 6.50 (2.00, 7.75) mm before treatment (Z=-0.179, -1.161; both P>0.05). The corneal fluorescein sodium staining points were 5.00 (2.00, 5.00) and 3.71 (0.00, 5.00) at 2 and 4 weeks after therapy in the experimental group, which were significantly lower than 7.10 (5.00, 7.00) before treatment (t=-2.895, -4.639; both P<0.05); those in the control group were 5.52 (0.00, 7.00) and 6.19 (0.75, 6.25) at 2 and 4 weeks after treatment, with a significant reduction in comparison with 8.90 (5.00, 10.50) before treatment (t=-2.776, -1.991; both P<0.05). The differences in the average total score of subjective symptoms, BUT, SIt, and corneal fluorescein sodium staining points between both groups were not statistically significant at each time point. The impression cytology grade was decreased from 1.72 (1.00, 2.00) before treatment to 0.94 (0.00, 2.00) at 4 weeks after therapy in the experimental group (Z=-2.803, P<0.05). The staining grade of conjunctival imprinted cells in the control group was 1.42 (1.00, 2.00) at 4 weeks, which showed no statistical significance compared with 1.56 (1.00, 2.00) before treatment (Z=1.195, P>0.05). The impression cytology grade was significantly reduced in the experimental group compared with the control group at 4 weeks after treatment (Z=-3.308, P<0.05). The number of goblet cells was 10.90 (5.00, 20.00) at 4 weeks after therapy in the experimental group, which was significantly higher than 6.30 (5.00, 8.00) before treatment (Z=-2.383, P<0.05); in the control group, it was 8.36 (4.00, 12.00) at 4 weeks after treatment, with no significant increase in comparison with that before treatment [7.55 (5.00, 11.00)] (Z=-0.095, P>0.05). The number of goblet cells was not significantly increased in the experimental group compared with the control group at 4 weeks after treatment (Z=-1.162, P>0.05). Most patients indicated that the drug was non-irritating, and no patient had intolerable irritation affecting daily lives at 4 weeks after therapy; there was no difference between the two groups (Z=-0.290, P>0.05). Conclusions: Both the rb-bFGF gel and the gel matrix can effectively improve the symptoms and signs of moderate dry eye. However, compared with the gel matrix, the rb-bFGF gel shows obvious advantages in promoting conjunctival epithelial cell repair and increasing the number of goblet cells. (Chin J Ophthalmol, 2021, 57: 930-938).

Human RIPK3 maintains MLKL in an inactive conformation prior to cell death by necroptosis

The ancestral origins of the lytic cell death mode, necroptosis, lie in host defense. However, the dysregulation of necroptosis in inflammatory diseases has led to widespread interest in targeting the pathway therapeutically. This mode of cell death is executed by the terminal effector, the MLKL pseudokinase, which is licensed to kill following phosphorylation by its upstream regulator, RIPK3 kinase. The precise molecular details underlying MLKL activation are still emerging and, intriguingly, appear to mechanistically-diverge between species. Here, we report the structure of the human RIPK3 kinase domain alone and in complex with the MLKL pseudokinase. These structures reveal how human RIPK3 structurally differs from its mouse counterpart, and how human RIPK3 maintains MLKL in an inactive conformation prior to induction of necroptosis. Residues within the RIPK3:MLKL C-lobe interface are crucial to complex assembly and necroptotic signaling in human cells, thereby rationalizing the strict species specificity governing RIPK3 activation of MLKL.

The intracellular domains of the EphB6 and EphA10 receptor tyrosine pseudokinases function as dynamic signalling hubs

EphB6 and EphA10 are two poorly characterised pseudokinase members of the Eph receptor family, which collectively serves as mediators of contact-dependent cell-cell communication to transmit extracellular cues into intracellular signals. As per their active counterparts, EphB6 and EphA10 deregulation is strongly linked to proliferative diseases. However, unlike active Eph receptors, whose catalytic activities are thought to initiate an intracellular signalling cascade, EphB6 and EphA10 are classified as catalytically dead, raising the question of how non-catalytic functions contribute to Eph receptor signalling homeostasis. In this study, we have characterised the biochemical properties and topology of the EphB6 and EphA10 intracellular regions comprising the juxtamembrane (JM) region, pseudokinase and SAM domains. Using small-angle X-ray scattering and cross-linking-mass spectrometry, we observed high flexibility within their intracellular regions in solution and a propensity for interaction between the component domains. We identified tyrosine residues in the JM region of EphB6 as EphB4 substrates, which can bind the SH2 domains of signalling effectors, including Abl, Src and Vav3, consistent with cellular roles in recruiting these proteins for downstream signalling. Furthermore, our finding that EphB6 and EphA10 can bind ATP and ATP-competitive small molecules raises the prospect that these pseudokinase domains could be pharmacologically targeted to counter oncogenic signalling.

[Effect of binocular accommodation and vergence function examinations and interventions on subjective discomfort of dry eye]

Objective: To investigate the accommodation and vergence (AV) function of patients with mild to moderate refractory dry eye symptoms, and determine the impact of relevant interventions on subjective symptoms. Methods: A total of 103 patients with dry eye disease (DED) in Zhongshan Ophthalmic Center between December 2017 and June 2019 were included. After 3-month conventional treatment, the patients entered the treatment-responsive group if ocular surface disease index (OSDI) decreased ≥12.5, and others were recruited into the refractory symptoms group. Binocular AV function, OSDI, tear break-up time (TBUT), Schirmer's test (ST) and fluorescein staining (FL) were determined in all the patients. Corrective therapy on the AV dysfunction was added in the refractory symptoms group besides the conventional therapy. The above-mentioned indexes were reexamined 8 weeks later. The incidence of AV dysfunction was compared between the refractory symptoms group and the treatment-responsive group. Moreover, the differences of OSDI and tear film stability were compared before and after the corrective therapy in the refractory symptoms group. Results: Sixty of 103 DED patients were classified into the refractory symptoms group [mean age: (27±6) years; 18 males and 25 females] and 43 into the treatment-responsive group [mean age: (30±6) years; 32 males and 28 females]. The incidence of AV dysfunction in the refractory symptom group (100%) was higher than that of the treatment responsive group (72.1%) (P<0.001). Forty patients with refractory symptoms accomplished the 8-week corrective therapy, and the OSDI score was significant improved (23.4±16.0 vs 40.6±15.7, P<0.001). However, further changes in ST, TBUT and FL were not detected in these patients (all P>0.05). Conclusions: There is a high prevalence of AV dysfunction in patients with refractory symptomatic DED. The corrective therapy on AV may improve the subjective symptoms in these patients.

Ubiquitylation of MLKL at lysine 219 positively regulates necroptosis-induced tissue injury and pathogen clearance

Necroptosis is a lytic, inflammatory form of cell death that not only contributes to pathogen clearance but can also lead to disease pathogenesis. Necroptosis is triggered by RIPK3-mediated phosphorylation of MLKL, which is thought to initiate MLKL oligomerisation, membrane translocation and membrane rupture, although the precise mechanism is incompletely understood. Here, we show that K63-linked ubiquitin chains are attached to MLKL during necroptosis and that ubiquitylation of MLKL at K219 significantly contributes to the cytotoxic potential of phosphorylated MLKL. The K219R MLKL mutation protects animals from necroptosis-induced skin damage and renders cells resistant to pathogen-induced necroptosis. Mechanistically, we show that ubiquitylation of MLKL at K219 is required for higher-order assembly of MLKL at membranes, facilitating its rupture and necroptosis. We demonstrate that K219 ubiquitylation licenses MLKL activity to induce lytic cell death, suggesting that necroptotic clearance of pathogens as well as MLKL-dependent pathologies are influenced by the ubiquitin-signalling system.

Granulovirus PK-1 kinase activity relies on a side-to-side dimerization mode centered on the regulatory αC helix

The life cycle of Baculoviridae family insect viruses depends on the viral protein kinase, PK-1, to phosphorylate the regulatory protein, p6.9, to induce baculoviral genome release. Here, we report the crystal structure of Cydia pomenella granulovirus PK-1, which, owing to its likely ancestral origin among host cell AGC kinases, exhibits a eukaryotic protein kinase fold. PK-1 occurs as a rigid dimer, where an antiparallel arrangement of the αC helices at the dimer core stabilizes PK-1 in a closed, active conformation. Dimerization is facilitated by C-lobe:C-lobe and N-lobe:N-lobe interactions between protomers, including the domain-swapping of an N-terminal helix that crowns a contiguous β-sheet formed by the two N-lobes. PK-1 retains a dimeric conformation in solution, which is crucial for catalytic activity. Our studies raise the prospect that parallel, side-to-side dimeric arrangements that lock kinase domains in a catalytically-active conformation could function more broadly as a regulatory mechanism among eukaryotic protein kinases.

The viral Protein Kinase-1 (PK-1) phosphorylates the regulatory protein p6.9, which facilitates baculoviral genome release. Here, the authors combine X-ray crystallography with biophysical and biochemical analyses as well as molecular dynamics simulations to characterize Cydia pomenella granulovirus PK-1, which forms a dimer with a parallel side-to-side arrangement of the kinase domains and furthermore, they provide insights into its catalytic mechanism and evolutionary relationships with other kinases.

Viral MLKL Homologs Subvert Necroptotic Cell Death by Sequestering Cellular RIPK3

Necroptotic cell death has been implicated in many human pathologies and is thought to have evolved as an innate immunity mechanism. The pathway relies on two key effectors: the kinase receptor-interacting protein kinase 3 (RIPK3) and the terminal effector, the pseudokinase mixed-lineage kinase-domain-like (MLKL). We identify proteins with high sequence similarity to the pseudokinase domain of MLKL in poxvirus genomes. Expression of these proteins from the BeAn 58058 and Cotia poxviruses, but not swinepox, in human and mouse cells blocks cellular MLKL activation and necroptotic cell death. We show that viral MLKL-like proteins function as dominant-negative mimics of host MLKL, which inhibit necroptosis by sequestering RIPK3 via its kinase domain to thwart MLKL engagement and phosphorylation. These data support an ancestral role for necroptosis in defense against pathogens. Furthermore, mimicry of a cellular pseudokinase by a pathogen adds to the growing repertoire of functions performed by pseudokinases in signal transduction.

Potent Inhibition of Necroptosis by Simultaneously Targeting Multiple Effectors of the Pathway

Necroptosis is an inflammatory form of programmed cell death that has been implicated in various human diseases. Compound 2 is a more potent analogue of the published compound 1 and inhibits necroptosis in human and murine cells at nanomolar concentrations. Several target engagement strategies were employed, including cellular thermal shift assays (CETSA) and diazirine-mediated photoaffinity labeling via a bifunctional photoaffinity probe derived from compound 2. These target engagement studies demonstrate that compound 2 binds to all three necroptotic effector proteins (mixed lineage kinase domain-like protein (MLKL), receptor-interacting serine/threonine protein kinase 1 (RIPK1) and receptor-interacting serine/threonine protein kinase 3 (RIPK3)) at different levels in vitro and in cells. Compound 2 also shows efficacy in vivo in a murine model of systemic inflammatory response syndrome (SIRS).

Distinct pseudokinase domain conformations underlie divergent activation mechanisms among vertebrate MLKL orthologues

The MLKL pseudokinase is the terminal effector in the necroptosis cell death pathway. Phosphorylation by its upstream regulator, RIPK3, triggers MLKL's conversion from a dormant cytoplasmic protein into oligomers that translocate to, and permeabilize, the plasma membrane to kill cells. The precise mechanisms underlying these processes are incompletely understood, and were proposed to differ between mouse and human cells. Here, we examine the divergence of activation mechanisms among nine vertebrate MLKL orthologues, revealing remarkable specificity of mouse and human RIPK3 for MLKL orthologues. Pig MLKL can restore necroptotic signaling in human cells; while horse and pig, but not rat, MLKL can reconstitute the mouse pathway. This selectivity can be rationalized from the distinct conformations observed in the crystal structures of horse and rat MLKL pseudokinase domains. These studies identify important differences in necroptotic signaling between species, and suggest that, more broadly, divergent regulatory mechanisms may exist among orthologous pseudoenzymes.

The Roc-COR tandem domain of leucine-rich repeat kinase 2 forms dimers and exhibits conventional Ras-like GTPase properties

The Parkinson's disease (PD)-causative leucine-rich repeat kinase 2 (LRRK2) belongs to the Roco family of G-proteins comprising a Ras-of-complex (Roc) domain followed by a C-terminal of Roc (COR) domain in tandem (called Roc-COR domain). Two prokaryotic Roc-COR domains have been characterized as 'G proteins activated by guanine nucleotide-dependent dimerization' (GADs), which require dimerization for activation of their GTPase activity and bind guanine nucleotides with relatively low affinities. Additionally, LRRK2 Roc domain in isolation binds guanine nucleotides with relatively low affinities. As such, LRRK2 GTPase domain was predicted to be a GAD. Herein, we describe the design and high-level expression of human LRRK2 Roc-COR domain (LRRK2 Roc-COR). Biochemical analyses of LRRK2 Roc-COR reveal that it forms homodimers, with the C-terminal portion of COR mediating its dimerization. Furthermore, it co-purifies and binds Mg²⁺ GTP/GDP at 1 : 1 stoichiometry, and it hydrolyzes GTP with K_m  and k_cat  of 22 nM and 4.70 × 10^-4  min^-1 ,  respectively. Thus, even though LRRK2 Roc-COR forms GAD-like homodimers, it exhibits conventional Ras-like GTPase properties, with high-affinity binding of Mg²⁺ -GTP/GDP and low intrinsic catalytic activity. The PD-causative Y1699C mutation mapped to the COR domain was previously reported to reduce the GTPase activity of full-length LRRK2. In contrast, this mutation induces no change in the GTPase activity, and only slight perturbations in the secondary structure contents of LRRK2 Roc-COR. As this mutation does not directly affect the GTPase activity of the isolated Roc-COR tandem, it is possible that the effects of this mutation on full-length LRRK2 occur via other functional domains. Open Practices Open Science: This manuscript was awarded with the Open Materials Badge. For more information see: https://cos.io/our-services/open-science-badges/.

Eph receptor signalling: from catalytic to non-catalytic functions

Eph receptors, the largest subfamily of receptor tyrosine kinases, are linked with proliferative disease, such as cancer, as a result of their deregulated expression or mutation. Unlike other tyrosine kinases that have been clinically targeted, the development of therapeutics against Eph receptors remains at a relatively early stage. The major reason is the limited understanding on the Eph receptor regulatory mechanisms at a molecular level. The complexity in understanding Eph signalling in cells arises due to following reasons: (1) Eph receptors comprise 14 members, two of which are pseudokinases, EphA10 and EphB6, with relatively uncharacterised function; (2) activation of Eph receptors results in dimerisation, oligomerisation and formation of clustered signalling centres at the plasma membrane, which can comprise different combinations of Eph receptors, leading to diverse downstream signalling outputs; (3) the non-catalytic functions of Eph receptors have been overlooked. This review provides a structural perspective of the intricate molecular mechanisms that drive Eph receptor signalling, and investigates the contribution of intra- and inter-molecular interactions between Eph receptors intracellular domains and their major binding partners. We focus on the non-catalytic functions of Eph receptors with relevance to cancer, which are further substantiated by exploring the role of the two pseudokinase Eph receptors, EphA10 and EphB6. Throughout this review, we carefully analyse and reconcile the existing/conflicting data in the field, to allow researchers to further the current understanding of Eph receptor signalling.

[Diagnostic criteria of demodex blepharitis]

Demodex infestation is a common cause of blepharitis and now is drawing more and more attention from clinicians. Demodex mite is the most common age-related ectoparasite of human being and may be detected from asymptomatic normal population. Furthermore, the pathogenesis of demodicosis remains unclear. Therefore, the commonly accepted diagnostic criteria of demodex infestation related blepharitis have not been established. Herein, we summarize the related studies about ocular demodicosis and comment the debates about the diagnosis of the disease. We also propose diagnostic criteria of demodex blepharitis. (Chin J Ophthalmol, 2017, 53: 648-652).

The impact of daycare attendance on outdoor free play in young children

Background

Outdoor free play is important for healthy growth and development in early childhood. Recent studies suggest that the majority of time spent in daycare is sedentary. The objective of this study was to determine whether there was an association between daycare attendance and parent-reported outdoor free play.

Methods

Healthy children aged 1-5 years recruited to The Applied Research Group for Kids! (TARGet Kids!), a primary care research network, were included. Parents reported daycare use, outdoor free play and potential confounding variables. Multivariable linear regression was used to determine the association between daycare attendance and outdoor free play, adjusted for age, sex, maternal ethnicity, maternal education, neighborhood income and season.

Results

There were 2810 children included in this study. Children aged 1 to <3 years (n = 1388) and ≥3 to 5 years (n = 1284) who attended daycare had 14.70 min less (95% CI -20.52, -8.87; P < 0.01) and 9.44 min less (95% CI -13.67, -5.20; P < 0.01) per day of outdoor free play compared with children who did not attend daycare, respectively.

Conclusions

Children who spend more time in daycare have less parent-reported outdoor free play. Parents may be relying on daycare to provide opportunity for outdoor free play and interventions to promote increased active play opportunities outside of daycare are needed.

[Analysis of the influence of iron overload in glucose metabolism in thalassemia major patients]

Objective: This study aimed at determining the characteristics of the glucose homeostasis and its relationship with iron overload of the patients with β-thalassemia major (β-TM). Method: From Sun Yat-sen Memorial Hospital between January 2014 and December 2015, a total of 57 transfusion-dependent β-TM patients with 5-18 years old were enrolled in this study and fasting blood glucose(FBG) and insulin level, serum ferritin (SF), serum iron, transferrin, total iron binding capacity, unsaturated iron binding capacity were determined.Insulin resistance index (IRI), insulin sensitivity index and β-cell function index (BFI) were also estimated. Besides, in 36 patients cardiac T2* and liver T2* were estimated. Result: (1) Four patients(7%) with β-TM were diagnosed diabetes mellitus, and 14(24%) had impaired fasting glucose. (2) The incidence of abnormal glucose metabolism was significantly different according to levels of SF and degrees of the cardiac iron overload(χ(2)=9.737, P<0.05; χ(2)=17.027, P<0.05). It rose while the level of SF increased and the degree of cardiac iron overload aggravated. (3) The incidence of abnormal glucose level was not significantly different in cases with different degree of liver iron overload.The severe group of liver iron overload had significantly higher levels of INS, HOMA-βFI, HOMA-ISI, HOMA-βFI than the non-severe group (Z=-2.434, -2.515, F=8.658, all P<0.05), while no differences were found in the level of FBG, HOMA-βFI between two groups. (4) The result of logistic regression analysis indicated that the cardiac T2* was a significant predictor for the incidence of abnormal glucose metabolism in TM patients (P=0.035, OR=1.182%, 95%CI=1.048 to 1.332). Conclusion: The high prevalence of abnormal glucose metabolism in β-TM patients was mainly closely related with the internal iron overload, especially in organs.The cardiac T2* was an independent risk factor for the incidence of abnormal glucose metabolism in TM patients.

Conservation and population genetic diversity of Curcuma wenyujin (Zingiberaceae), a multifunctional medicinal herb

Curcuma wenyujin is an important multifunctional medicinal herb in China. Currently, populations of C. wenyujin are decreasing, and wild individuals have almost disappeared from their natural habitats. Moreover, little is known regarding the molecular characteristics of this plant. In this study, we investigated the genetic diversity and variation of five populations of C. wenyujin, using ran-dom amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. We found that the percentages of polymorphic loci (PPL) at the species level (98.25% by RAPD and 100% by ISSR) were significantly higher than those at the population level (66.32% by RAPD and 67.14% by ISSR). The highest values of PPL, expected heterozygosity, and Shannon's information index were in Pop1, while the lowest values were in Pop2. Both DNA markers revealed a short genetic distance between Pop1 and Pop2 (0.1424 by RAPD and 0.1904 by ISSR). Phylogenetic trees produced similar results, with Pop1, Pop2, and Pop5 in one group and Pop3 and Pop4 in another. There were no significant correlations between their genetic distances and their geographical distances. The highest genetic diversity was in Pop1 and the lowest was in Pop2, and genetic diversity at the species level was relatively low, but much higher than that at the population level. We recommended the establishment of a germplasm bank, in situ con-servation, and propagation of wild individuals. The present study will improve the evaluation, protection, and utilization of the population resources of C. wenyujin.

Increasing testicular temperature by exposure to elevated ambient temperatures restores spermatogenesis in adult Utp14b (jsd) mutant (jsd) mice

Because mutations in the human UTP14C gene are associated with male infertility, we sought to develop a method for fertility restoration in azoospermic mice with a mutation in the orthologous Utp14b(jsd) (jsd) gene that have spermatogonial arrest. The method is based on our observation that elevation of testicular temperatures restores spermatogonial differentiation in jsd mutant mice. To non-surgically raise intrascrotal temperatures we placed these mice in incubators at different elevated ambient temperatures. Exposure of jsd/jsd mice to ambient temperatures of 34.5 °C or 35.5 °C for 24 days increased the proportion of tubules with spermatocytes from 0% in untreated controls to over 80%. As those higher temperatures interfere with spermatid differentiation, the mice were then transferred to incubators at 32-32.5 °C for the next 24 days. These environments allowed differentiation to progress, resulting in up to 42% of tubules having late spermatids and about half of the mutant mice having spermatozoa in testicular suspensions. When these spermatozoa were used in intracytoplasmic sperm injection, all gave rise to viable healthy offspring with normal weight gain and fertility. The successful restoration of fertility in Utp14b mutant mice suggests that transient testicular warming might also be useful for spermatogenesis recovery in infertile men with UTP14C gene mutations.

Spironolactone prevents dietary-induced metabolic syndrome by inhibiting PI3-K/Akt and p38MAPK signaling pathways

OBJECTIVES

Aim of the study is to evaluate the impact of spironolactone (SPL) on indexes of metabolic syndrome (MS) and further investigate the mechanisms underlying its protective effects.

METHODS

A rat model of MS was established by administering a fat- and salt-enriched diet (FS diet). The occurrence of MS was examined by measurement of blood pressure (BP), aldosterone (ALD) content, blood lipid (BL), glucose and insulin levels. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Pancreatic gland tissue injury was assessed by β-cell apoptosis. Mineralocorticoid receptor (MR) activity, phosphatidylinositol 3- kinase/Akt (PI3-K/Akt), and phosphorylation of p38MAPK (Pp38MAPK) in pancreatic gland tissue were evaluated by western blot analysis.

RESULTS

SPL prevented hypertension, and dyslipidemia during MS induced by the intake of FS diet, but had no effect on K+ and Na+ disturbances. Furthermore, SPL significantly attenuated ALD and MR expression levels after FS diet. Finally, SPL inhibited phosphorylation protein kinase B (p- PKB) activation in the pancreatic gland tissue, a downstream target of PI3-K, and phosphorylation of p38MAPK pathway, critical for cellular apoptosis.

CONCLUSIONS

This study demonstrates that SPL exerts a protective effect on hypertension and dyslipidemia. This protective effect may depend, at least in part, on MAPK and PI3-K pathways.

Anti-inflammatory activities of fractions from Geranium nepalense and related polyphenols

Geranium nepalense Sweet is a common Chinese herbal medicine and has been used as influenza, dysentery, antiphlogistic and analgesic tonic, hemostatic, stomachic, and antidiabetic drugs. The anti-inflammatory effects of G. nepalense on tetradecanoyl phorbol acetate (TPA)-induced mouse ear edema were studied in this work. The results showed that ethyl acetate fraction of the water extract of G. nepalense possessed significant activity at 2.5 g/kg (p < 0.01) with aspirin as a positive control (0.6 g/kg). Six polyphenolic compounds, including three flavonoids, i.e. kaempferol, kaempferol-7-O-β-D-glucopyranoside, and quercetin-7-O-α-rhamnopyranoside, and two tannins, i.e. pyrogallol and gallic acid, and one lignin, i.e. epipinoresinol, were isolated and characterized from ethyl acetate fraction. The isolation of polyphenols provides a clue for beneficial effects of G. nepalense in the demonstrated anti-inflammatory activity.

MUC19 expression in human ocular surface and lacrimal gland and its alteration in Sjögren syndrome patients

This study investigated the expression of MUC19, a newly discovered gel-forming mucin gene, in normal human lacrimal functional unit components and its alteration in Sjögren syndrome patients. Real-time PCR and immunohistochemistry were performed to determine the expression of MUC19 and MUC5AC in human cornea, conjunctiva, and lacrimal gland tissues. Conjunctival impression cytology specimens were collected from normal control subjects and Sjögren syndrome patients for Real-time PCR, PAS staining, and immunohistochemistry assays. In addition, conjunctiva biopsy specimens from both groups were examined for the expression differences of MUC19 and MUC5AC at both mRNA and protein level. The MUC19 mRNA was found to be present in cornea, conjunctiva and lacrimal gland tissues. The immunohistochemical staining of mucins showed that MUC19 was expressed in epithelial cells from corneal, conjunctival, and lacrimal gland tissues. In contrast, MUC5AC mRNA was only present in conjunctiva and lacrimal gland tissues, but not in cornea. Immunostaining demonstrates the co-staining of MUC19 and MUC5AC in conjunctival goblet cells. Consistent with the significant decrease of mucous secretion, both MUC19 and MUC5AC were decreased in conjunctiva of Sjögren syndrome patients compared to normal subjects. Considering the contribution of gel-forming mucins to the homeostasis of the ocular surface, the decreased expression of MUC19 and MUC5AC in Sjögren syndrome patients suggested that these mucins may be involved in the disruption of the ocular surface homeostasis in this disease.

Two variants of zebrafish p100 are expressed during embryogenesis and regulated by Nodal signaling

Human p100 protein was first identified as a transcriptional coactivator of Epstein-Barr virus nuclear antigen 2, and has been shown to be a coactivator of other cellular transactivators. Its roles in development of vertebrate embryos, however, have not been reported. We have identified a zebrafish ortholog of the human p100 coactivator. The zebrafish p100 transcript is processed to two alternative variants, long and short forms, referred to as p100L and p100S, respectively. Both GFP-p100L and GFP-p100S fusion proteins are located in the cytoplasm of transfected culture cells and microinjected embryonic cells. Analysis of transcripts with Northern blots revealed the presence of p100L and lower amounts of p100S mRNAs from the one-cell stage throughout the life cycle. Whole-mount in situ hybridization shows that p100L and p100S share the same spatiotemporal expression pattern. Their zygotic expression is initially restricted to axial mesoderm precursors during gastrulation, and then spreads over other tissues during segmentation, and finally is constrained to some internal organs at day 5. We also find that Nodal signaling is essential for the zygotic expression of p100. These studies pave the way to understanding in depth the role of p100 during vertebrate embryogenesis.