Somatic Mutations within Myocilin due to Aging May Be a Potential Risk Factor for Glaucoma

Glaucoma is a chronic optic neuropathy that leads to irreversible vision loss. Aging and family history are the two most important risk factors of glaucoma. One of the most studied genes involved in the onset of open-angle glaucoma is myocilin (MYOC). About 105 germline mutations within MYOC are known to be associated with glaucoma and result in endoplasmic reticulum (ER) stress, which leads to trabecular meshwork (TM) cell death and subsequent intraocular pressure (IOP) elevation. However, only about 4% of the population carry these mutations. An analysis of MYOC somatic cancer-associated mutations revealed a notable overlap with pathogenic glaucoma variants. Because TM cells have the potential to accumulate somatic mutations at a rapid rate due to ultraviolet (UV) light exposure, we propose that an accumulation of somatic mutations within MYOC is an important contributor to the onset of glaucoma.

[Study on primary screening technique for children with autism spectrum disorder]

To explore screening tools for children with autism spectrum disorder (ASD), which are convenient for primary hospitals, it can provide basic data for formulating ASD prevention policies. This was a cross-sectional study by cluster sampling. Huyi District and Xincheng District were extracted for investigation in Xi'an City. From July 2021 to September 2022, all children aged from 3 months to 36 months who live in the two districts were subjected to primary screening. The child care physician used the routine screening tool "warning signs checklist for screening psychological, behavioral and developmental problems of children" and cartoon pictures of "early high-risk warning signs of autism", the children who were positive in the initial screening were referred to the district level maternal and child health hospital for re-screening, and those who were positive in the re-screening were referred to Xi 'an Children's Hospital for diagnosis. The results showed that a total of 17 905 children aged from 3 months to 36 months were initially screened in the two districts, including 10 588 children aged from 18 months to 36 months, 50 children who were positive in the initial screening and 50 children who were re-screened. 23 children (18 boys and 5 girls) were diagnosed with ASD. The prevalence rate of ASD in children was 2.17‰ (95% confidence interval:1.29‰-3.06‰). 42 children were positive for "warning signs checklist" at the preliminary screening, and 19 were confirmed as ASD. 27 children were positive for "cartoon pictures" in the preliminary screening, and 23 were confirmed with ASD. The "cartoon pictures" in the preliminary screening and diagnosis of consistent rate was higher than the "warning signs checklist", two kinds of screening methods comparison were statistically significant difference in the odds of consistent (χ2=11.01, P=0.001). In conclusion, relying on the three-level network of maternal and child health care, it is conducive to the whole process management of screening and diagnosis of children with ASD, and to guide the formulation of prevention policies. The cartoon pictures of "early high-risk warning signs of autism" can assist the identification of children with ASD based on the "warning signs checklist", which is simple, effective and suitable for promotion in the community health care.

Wnt activation as a potential therapeutic approach to treat partial limbal stem cell deficiency

Limbal epithelial stem/progenitor cells (LSCs) are adult stem cells located at the limbus, tightly regulated by their niche involving numerous signaling pathways, such as Wnt. Wnt proteins are secreted morphogens that play critical roles in embryonic development, stem cell proliferation, self-renewal, tissue regeneration, and remodeling in adults. It has been shown that a small molecule Wnt mimic could improve LSCs expansion ex vivo. Damage to the LSCs and/or their niche can lead to limbal stem cell deficiency (LSCD), a condition that can cause corneal blindness and is difficult to treat. This study explored if repopulating residual LSCs in partial LSCD through Wnt activation could be a novel therapeutic approach. To mimic LSCD due to a chemical injury, single cultured LSCs were exposed to various concentrations of sodium hydroxide. A progressive loss of the LSCs phenotype was observed: the percentage of p63bright cells and cytokeratin (K)14+ cells decreased while the percentage of K12+ increased. Wnt activation was attained by treating the LSCs with lithium chloride (LiCl) and a small-molecule Wnt mimic, respectively. After 18 h of treatment, LSCs proliferation was increased, and the LSCs phenotype was recovered, while the untreated cells did not proliferate and lost their phenotype. The percentage of p63bright cells was significantly higher in the Wnt mimic-treated cells compared with untreated cells, while the percentage of K12+ cells was significantly lower. These findings suggest that local Wnt activation may rescue LSCs upon alkaline injury.

[Curative effects of ultrathin anterolateral femoral flap in one-stage split-finger repair of palmar combined with multiple finger wounds]

Objective: To explore the curative effects of ultrathin anterolateral femoral flap in one-stage split-finger repair of palmar combined with multiple finger wounds. Methods: A retrospective observational study was conducted. From October 2016 to June 2018, 20 patients with wounds on palms and multiple fingers who met the inclusion criteria were admitted to Zhengzhou First People's Hospital, including 15 males and 5 females, aged 18 to 77 years. After debridement, the wound area was 8 cm×4 cm-17 cm×12 cm. The wound was repaired by ultrathin anterolateral femoral flap with area of 9 cm×5 cm to 19 cm×13 cm. According to the wound condition of finger, the finger division was performed in one stage, and the length-to-width ratio of the split-finger flap was 2.0:1.0-2.5:1.0. During the surgery, the descending branches of lateral circumflex femoral artery and accompanying vein of flap were anastomosed end-to-end to the radial artery and vein in the recipient area, respectively, and the anterolateral femoral cutaneous nerve of flap was bridged with the superficial branch of radial nerve in the recipient area. The wounds in the donor area of flap in 14 patients were sutured directly, the wounds in the donor area of flap in 3 patients were repaired by relay superficial iliac circumflex artery perforator flap, and the wounds in the donor area of flap in 3 patients were covered by free trunk medium-thick skin graft. The survival of flap, occurrence of vascular crisis and other complications, and healing of wounds in the donor area of flap were recorded. The appearance of flap, scar hyperplasia in the donor and recipient areas and the patients' satisfaction with the shape and function of the donor and recipient areas were followed up. In 1 year after surgery, the two-point discrimination distance of the flap was measured, and the recovery of hand function was evaluated by the trial standard for the evaluation of the functions of the upper limbs of the Hand Surgery Society of the Chinese Medical Association. Results: The flaps of 17 patients survived without vascular crisis or other complications after surgery. The flap of 1 patient had poor blood circulation and partial necrosis, and the wound was healed 14 days after dressing change and grafting of split-thickness skin graft from head. Two patients had mild cyanosis at the margin of flap after surgery, which disappeared spontaneously 5 days later. Incisions at donor site, relay flaps, and skin grafts of all patients survived well. After surgery, the color and texture of flap were basically the same as that of the normal skin of hand, and linear scars were observed in the donor and recipient areas. The patients were satisfied with the recovery of appearance and function of donor and recipient areas. After 1 year of follow-up, the patients' hand sensory function recovered well, the two-point discrimination distance of flap was 4-6 mm, and the recovery of hand function was evaluated as excellent in 18 cases and good in 2 cases. Conclusions: The ultrathin anterolateral femoral flap in repairing the palmar combined with multiple finger wounds in one-stage split-finger can significantly reduce the number of surgeries and improve the function and beauty of the hand, so it is worthy of clinical promotion.

Dexamethasone Modulates the Dynamics of Wnt Signaling in Human Trabecular Meshwork Cells

Trabecular meshwork (TM) tissue is highly specialized, and its structural integrity is crucial for maintaining homeostatic intraocular pressure (IOP). The administration of glucocorticoids, such as dexamethasone (DEX), can perturb the TM structure and significantly increase IOP in susceptible individuals, resulting in ocular diseases such as steroid-induced glaucoma, a form of open-angle glaucoma. Although the exact mechanism involved in steroid-induced glaucoma remains elusive, increasing evidence suggests that DEX may act through various signaling cascades in TM cells. Despite uncertainty surrounding the specific process by which steroid-induced glaucoma occurs, there is growing evidence to indicate that DEX can impact multiple signaling pathways within TM cells. In this study, we examined the impact of DEX treatment on the Wnt signaling pathway in TM cells, given that Wnt signaling has been reported to play a crucial role in regulating extracellular matrix (ECM) levels in the TM. To further elucidate the role of Wnt signaling in the glaucomatous phenotype, we examined mRNA expression patterns between Wnt signaling markers AXIN2 and sFRP1 and DEX-mediated induction of myocilin (MYOC) mRNA and protein levels over 10 days in DEX-treated primary TM cells. We observed a sequential pattern of peak expression between AXIN2, sFRP1, and MYOC. Based on the study, we propose that sFRP1 upregulation could be a result of a negative feedback mechanism generated by stressed TM cells to suppress abnormal Wnt signaling activities.

R-etodolac is a more potent Wnt signaling inhibitor than enantiomer, S-etodolac

Etodolac is an FDA-approved nonsteroidal anti-inflammatory drug (NSAID) used to treat a variety of inflammatory diseases. The drug is administered as a racemate (50/50 mixture of R- and S- enantiomers), however, studies have shown that the two enantiomers have distinct biologic and pharmacokinetic differences. Wnt signaling, which plays key roles in cell proliferation, polarity, and differentiation, has been shown to be inhibited by R-etodolac; however, comparative analyses of R- and S-etodolac in this function have not been conducted. We used in silico molecular docking and TOPflash functional biologic assays to compare R- and S-enantiomers effect on Wnt signaling inhibition. Further, we used a cultivated limbal stem epithelial cell (cLSCs) model to investigate enantiospecific changes in the colony-forming efficiency (CFE) of cLSCs. The data shows that R-etodolac is a more potent inhibitor of Wnt signaling. In addition, consistently, while both enantiomers demonstrate a dose-dependent decrease in CFE of cLSCs, R-etodolac is a more potent inhibitor.

Characterizing the metabolic profile of dexamethasone treated human trabecular meshwork cells

The trabecular meshwork (TM) is the leading site of aqueous humor outflow in the eye and plays a critical role in maintaining normal intraocular pressure. When the TM fails to maintain normal intraocular pressure, glaucoma may develop. Mitochondrial damage has previously been found in glaucomatous TM cells; however, the precise metabolic activity of glaucomatous TM cells has yet to be quantitatively assessed. Using dexamethasone (Dex) treated primary human TM cells to model glaucomatous TM cells, we measure the respiratory and glycolytic activity of Dex-treated TM cells with an extracellular flux assay. We found that Dex-treated TM cells had quantifiably altered metabolic profiles, including increased spare respiratory capacity and ATP production rate from oxidative phosphorylation. Therefore, we propose that reversing or preventing these metabolic changes may represent an avenue for future research.

Age at Glaucoma Diagnosis in Germline Myocilin Mutation Patients: Associations with Polymorphisms in Protein Stabilities

Glaucoma is the leading cause of irreversible blindness worldwide, with elevated intraocular pressure (IOP) as the only known modifiable risk factor. Trabecular meshwork (TM)-inducible myocilin (the MYOC gene) was the first to be identified and linked to juvenile and primary open-angle glaucoma. It has been suggested that mutations in the MYOC gene and the aggregation of mutant myocilin in the endoplasmic reticulum (ER) of TM may cause ER stress, resulting in a reduced outflow of aqueous humor and an increase in IOP. We selected 20 MYOC mutations with experimentally determined melting temperatures of mutated myocilin proteins. We included 40 published studies with at least one glaucoma patient with one of these 20 MYOC mutations and information on age at glaucoma diagnosis. Based on data from 458 patients, we found that a statistically significant but weak correlation was present between age and melting temperature based on various assumptions for age. We therefore conclude that genetic analysis of MYOC mutations alone cannot be used to accurately predict age at glaucoma diagnosis. However, it might be an important prognostic factor combined with other clinical factors for critical and early detection of glaucoma.

Loss of CDCP1 triggers FAK activation in detached prostate cancer cells

A major metastasis suppressing mechanism is the rapid apoptotic death of cancer cells upon detachment from extracellular matrix, a process called anoikis. Focal adhesion kinase (PTK2/FAK) is a key enzyme involved in evasion of anoikis. We show that loss of the Cub-domain containing protein-1 (CDCP1), paradoxically stimulates FAK activation in the detached state of prostate cancer cells. In CDCP1^low DU145 and PC3 prostate cancer cells, detachment-activation of FAK occurs through local production of PI(4,5)P₂. PI(4,5)P₂ is generated by the PIP5K1c-201 splicing isoform of PIP5K1c, which contains a unique SRC phosphorylation site. In the detached state, reduced expression of CDCP1 and an alternative CDCP1-independent SRC activation mechanism triggers PIP5K1c-pY644 phosphorylation by SRC. This causes a switch of Talin binding from β1-integrin to PIP5K1c-pY644 and leads to activation of PIP5K1c-FAK. Reduced CDCP1 expression also inactivates CDK5, a negative regulator of PIP5K1c. Furthermore, immersion of prostate cancer cells in 10% human plasma or fetal bovine serum is required for activation of PIP5K1c-FAK. The PIP5K1c induced detachment-activation of FAK in preclinical models sensitizes CDCP1^low prostate cancer cells to FAK inhibitors. In patients, CDCP1^High versus CDCP1^low circulating tumor cells differ in expression of AR-v7, ONECUT2 and HOXB13 oncogenes and TMPRSS2 and display intra-patient heterogeneity of FAK-pY397 expression. Taken together, CDCP1^low and CDCP1^high detached prostate cancer cells activate distinct cytoplasmic kinase complexes and targetable transcription factors, which has important therapeutic implications.

Wnt signaling activation: targets and therapeutic opportunities for stem cell therapy and regenerative medicine

Wnt proteins are secreted morphogens that play critical roles in embryonic development, stem cell proliferation, self-renewal, tissue regeneration and remodeling in adults. While aberrant Wnt signaling contributes to diseases such as cancer, activation of Wnt/β-catenin signaling is a target of interest in stem cell therapy and regenerative medicine. Recent high throughput screenings from chemical and biological libraries, combined with improved gene expression reporter assays of Wnt/β-catenin activation together with rational drug design, led to the development of a myriad of Wnt activators, with different mechanisms of actions. Among them, Wnt mimics, antibodies targeting Wnt inhibitors, glycogen-synthase-3β inhibitors, and indirubins and other natural product derivatives are emerging modalities to treat bone, neurodegenerative, eye, and metabolic disorders, as well as prevent ageing. Nevertheless, the creation of Wnt-based therapies has been hampered by challenges in developing potent and selective Wnt activators without off-target effects, such as oncogenesis. On the other hand, to avoid these risks, their use to promote ex vivo expansion during tissue engineering is a promising application.

Nonlinear microfluidics: device physics, functions, and applications

The microfluidic flow is typically laminar due to the dominant viscous effects. At Reynolds numbers far below 1 (Re ≪ 1), the fluid inertia can be neglected. For the steady flow of incompressible Newtonian fluids, it approaches linear Stokes flow. At intermediate Re, there exists a weak-inertia flow regime where secondary flows such as Dean vortices are accessible for microfluidic manipulations. Apart from the fluid inertia, other nonlinear factors such as the non-Newtonian fluid properties, concurrent flow of dissimilar fluids, compliant fluidic structures and stimuli-responsive materials can also cause intriguing flow behaviours. Through proper designs, they can be applied for a variety of microfluidic components including mixers, valves, oscillators, stabilizers and auto-regulators etc., greatly enriching the microfluidic flow control and manipulation strategies. Due to its unique working characteristics and advantages, nonlinear microfluidics has increasingly attracted extensive attention. This review presents a systematic survey on this subject. The designs of typical nonlinear microfluidic devices, their working mechanisms, key applications, and the perspective of their future developments will be discussed. The nonlinear microfluidic techniques are believed to play an essential role in the next generation of highly-integrated, automated, and intelligent microfluidics.

Three-dimensional Imaging Coupled with Topological Quantification Uncovers Retinal Vascular Plexuses Undergoing Obliteration

Introduction: Murine models provide microvascular insights into the 3-D network disarray seen in retinopathy and cardiovascular diseases. Light-sheet fluorescence microscopy (LSFM) has emerged to capture retinal vasculature in 3-D, allowing for assessment of the progression of retinopathy and the potential to screen new therapeutic targets in mice. We hereby coupled LSFM, also known as selective plane illumination microscopy, with topological quantification, to characterize the retinal vascular plexuses undergoing preferential obliteration. Method and Result: In postnatal mice, we revealed the 3-D retinal microvascular network in which the vertical sprouts bridge the primary (inner) and secondary (outer) plexuses, whereas, in an oxygen-induced retinopathy (OIR) mouse model, we demonstrated preferential obliteration of the secondary plexus and bridging vessels with a relatively unscathed primary plexus. Using clustering coefficients and Euler numbers, we computed the local versus global vascular connectivity. While local connectivity was preserved (p > 0.05, n = 5 vs. normoxia), the global vascular connectivity in hyperoxia-exposed retinas was significantly reduced (p < 0.05, n = 5 vs. normoxia). Applying principal component analysis (PCA) for auto-segmentation of the vertical sprouts, we corroborated the obliteration of the vertical sprouts bridging the secondary plexuses, as evidenced by impaired vascular branching and connectivity, and reduction in vessel volumes and lengths (p < 0.05, n = 5 vs. normoxia). Conclusion: Coupling 3-D LSFM with topological quantification uncovered the retinal vasculature undergoing hyperoxia-induced obliteration from the secondary (outer) plexus to the vertical sprouts. The use of clustering coefficients, Euler's number, and PCA provided new network insights into OIR-associated vascular obliteration, with translational significance for investigating therapeutic interventions to prevent visual impairment.

A Small-Molecule Wnt Mimic Improves Human Limbal Stem Cell Ex Vivo Expansion

Ex vivo cultured limbal stem/progenitor cells is an effective alternative to other surgical treatments for limbal stem cell deficiency, but a standard xenobiotic-free method for culturing the LSCs in vitro needs to be optimized. Because Wnt ligands are required for LSC expansion and preservation in vitro, to create a small-molecule Wnt mimic, we created a consolidated compound by linking a Wnt inhibitor that binds to the Wnt co-receptor Frizzled to a peptide derived from the N-terminal Dickkopf-1 that binds to Lrp (low-density lipoprotein receptor-related protein) 5/6, another Wnt co-receptor. This Wnt mimic not only enhances cellular Wnt signaling activation, but also improves the progenitor cell phenotype of in vitro cultured limbal epithelial cells. As the maintenance of stem cell characteristics in the process of culture expansion is essential for the success of ocular surface reconstruction, the small molecules generated in this study may be helpful in the development of pharmaceutical reagents for treating corneal wounds.

[Changes of sex hormones and sex hormone-binding globulin levels in male adults with hyperthyroidism before and after antithyroid drug treatment]

Objective: To observe the changes of sex hormone and sex hormone-binding globulin (SHBG) levels in young male patients with hyperthyroidism before and after antithyroid drug (ATD) treatment. Methods: Between January 2015 and July 2016, forty male patients with hyperthyroidism aged 19-52 years (with an median age of 33.1 years) were enrolled in the Department of Endocrinology of Peking Union Medical College Hospital. Blood samples were taken before treatment and at 1 month, 2 months, 3 months and 5 months after treatment to evaluate thyroid function, follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone(T), free testosterone(FT), estradiol(E2), prolactin and SHBG. Results: A total of 40 patients were enrolled but only 35 patients completed the follow-up. The patients had high levels of thyroid function, SHBG and sex hormones before treatment. Before treatment, free thyroxine (FT(4)), free triiodothyronine (FT(3)), SHBG, LH, estradiol, testosterone and free testosterone was (0.30±0.12) pmol/L, (9.68±4.73) pmol/L, (146±111) nmol/L, (8.41±3.61) U/L, (19.9±7.7) pmol/L, (29.9±9.5) nmol/L and (0.24±0.08) nmol/L, respectively. After treatment, the level of triiodothyronine, thyroxine, FT(3) and FT(4) gradually decreased to normal (all P<0.001). Thyroid stimulating hormone (TSH) gradually increased to normal (P<0.001). LH and estradiol levels gradually decreased (all P<0.001). FSH decreased but the difference was not statistically significant. Prolactin did not change significantly. Testosterone and SHBG levels decreased significantly while the levels of free testosterone, free testosterone percentage (FT%), bio-available testosterone (BAT), bio-available testosterone percentage (BAT%), free androgen index (FAI) gradually increased and stabilized (all P<0.001). The difference was not statistically significant between T/LH and E2/LH before and after treatment (all P>0.05). However FT/LH gradually increased and its difference was statistically significant (P<0.001). Conclusion: The levels of LH, estradiol, testosterone and SHBG in male patients with hyperthyroidism significantly increased, while the free testosterone level decreased, but they all gradually returned to normal with the lowering of thyroid hormone levels during ATD treatment.

Wnt Signaling Is Required for the Maintenance of Human Limbal Stem/Progenitor Cells In Vitro

Purpose

A chemical approach to examine the role of Wnt signaling in maintaining the stemness and/or proliferation of limbal stem/progenitor cells (LSCs).

Methods

LSCs were isolated from human donor eyes and cultured as single cells for 12 to 14 days with the following small molecules: IIIC3, an antagonist of the Wnt signaling inhibitor Dickkopf (DKK), and IC15, a Wnt signaling inhibitor. Proliferation of LSCs in the presence of IIIC3 and IC15 was determined by the number of cells and colonies established. Maintenance of stemness was determined by p63α, cytokeratin (K)12, and K14 expression.

Results

Activation of Wnt, through IIIC3-mediated DKK inhibition, resulted in similar colony forming efficiency (CFE) as in the untreated LSCs, but significantly increased the number of cultivated cells 7.21% with 5 μM. Inhibition of Wnt with IC15 significantly reduced the CFE (P ≤ 0.01) and the number of cultivated cells by 16% to 29%. Percentage of cells expressing high levels of p63α (p63α^bright) and quantity of small cells (≤12 μm), which contain the LSCs, increased 4.71% and 11.26% (both P < 0.05), respectively, with 5 μM IIIC3. All concentrations of IIIC3 and IC15 retained the K14 undifferentiated marker (97%), while differentiation, as detected by expression of K12, was found in up to 2% of cells in 1 μM IIIC3, 1 μM IC15, or 5 μM IIIC3.

Conclusions

Wnt signaling is required in LSC proliferation and maintenance of an undifferentiated state. The current study is a proof of concept that the Wnt pathway could be modulated in LSCs to enhance or decrease the efficiency of human LSC expansion.

Oxidative stress upregulates Wnt signaling in human retinal microvascular endothelial cells through activation of disheveled

Abnormal retinal neovascularization associated with various retinopathies can result in irreversible vision loss. Although the mechanisms involved in this occurrence is unclear, increasing evidence suggests that aberrant Wnt signaling participates in the pathogenesis of abnormal neovascularization. Because Wnt signaling upregulation can be induced by oxidative stress through the activation of disheveled (DVL), a key molecule in the Wnt signaling pathway, we investigated whether oxidative stress can activate Wnt signaling and induce angiogenic phenotypes in human retinal microvascular endothelial cells (HRMECs). We found that increased Wnt signaling activity, as well as enhanced angiogenic phenotypes, such as tube formation and cell migration, were detected in the hydrogen peroxide-treated HRMECs. Moreover, these effects were effectively suppressed by a small-molecule Wnt inhibitor targeting the PDZ domain of DVL. Therefore, we propose that targeting abnormal Wnt signaling at the DVL level with a small-molecule inhibitor may represent a novel approach in retinal neovascularization treatment and prevention.

[A study of bacterial distribution and drug resistance in skin and soft tissue infection]

Objective: To investigate pathogenic bacteria and drug resistance in the patients with skin and soft tissue infection in order to provide the scientific evidences for clinical reasonable use of antibiotics. Methods: A retrospective analysis was performed on patients with skin and soft tissue infections in Department of Dermatology, Peking University Third Hospital from January 2012 to December 2017. Pus, secretions, skin lesions, urine, throat swabs, and alveolar lavage fluid were collected for bacterial culture, bacterial species were identified by VITEK2 Compact system and BD-Bruker MALDI Biotyper system. Drug resistance was detected by K-B agar diffusion method recommended by CLSI. Results: A total of 392 strains of bacteria were isolated from 327 patients distributed in 21 genus and 56 species, of which 225 were gram-positive cocci (57.40%), 114 were gram-negative rods (29.08%), 46 were gram-positive rods (11.73%), and 7 were gram-negative cocci (1.79%). The top 3 bacteria were Staphylococcus aureus 91(23.21%), Staphylococcus epidermidis 42 (10.71%), and Pseudomonas aeruginosa 24 (6.12%). Staphylococcus had a high rate of resistance to penicillin and erythromycin (>50%). Gram-negative rods were resistant to ampicillin (86.1%), and also had certain resistance to most second-generation and some third-generation cephalosporin (about 50%). There was no significant change in the drug resistance rate of MRSA compared to MSSA. Only the resistance rate to tetracycline was statistically different (P<0.05). Conclusion: The emergence of drug-resistant strains is an important factor leading to refractory infections. There are a wide range of pathogenic bacteria species among the skin and soft tissue infection patients, and antimicrobial drugs should be chosen wisely according to drug sensitivity.

Tunable hybridization of graphene plasmons and dielectric modes for highly confined light transmit at terahertz wavelength

We theoretically report a novel graphene-based hybrid plasmonic waveguide (GHPW) by integrating a GaAs micro-tube on a silica spacer that is supported by a graphene-coated substrate. In comprehensive numerical simulations on guiding properties of the GHPW, it was found that the size of hybrid plasmonic mode (TM) can be reduced significantly to ~10^-4(λ²/4), in conjunction with long propagation distances up to tens of micrometers by tuning the the waveguide's key structure parameters and graphene's chemical potential. Moreover, crosstalk between two adjacent GHPWs that are placed on the same substrate has been analyzed and ultralow crosstalk can be realized. The proposed scheme potentially enables realization of the various high performance nanophotonic components-based subwavelength plasmonic waveguides in terahertz domain.

[Clinical analysis of candidemia in immunocompetent patients]

OBJECTIVE

To investigate the etiological and clinical characteristics of immunocompetent patients with candidemia.

METHODS

The clinical and microbiological data of patients diagnosed as candidemia admitted in Peking University Third Hospital from January 2010 to June 2016 were retrospectively analyzed. Underlying diseases, Candida spp. colonization, clinical manifestations, microbiological data, treatment and the outcome were compared between the HIV-negative immunocompromised (IC) and nonimmunocompromised (NIC) patients.

RESULTS

A total of 62 cases diagnosed as candidemia were analyzed including 36 men and 26 women, with 16 to 100 years of age [(66.02±17.65) years]. There were 30 NIC and 32 HIV-negative IC patients respectively. In the NIC patients, there were 19 cases (19/30, 63.33%) with admission in intensive care unit (ICU), 21 (21/30, 70.00%) associated diabetes mellitus or uncontrolled hyperglycemia and 22 (22/30,73.33%) receiving invasive mechanical ventilation, while in the HIV-negative IC patients, there were 8 (8/32, 25.00%), 13 (13/32, 40.63%) and 7 (7/32, 21.88%) respectively (P<0.05). The NIC patients had higher acute physiology and chronic health evaluation (APACHE II) scores and sequential organ failure assessment (SOFA) scores both at admission (19.98±5.81, 6.04±6.14) and candidemia onset (25.61±6.52, 12.75±8.42) than the HIV-negative IC patients (APACHEII 15.09±5.82, 22.15±5.98) and SOFA 2.87±2.73, 7.66±5.64 respectively (P<0.05). In the NIC patients, twenty-one cases (21/30, 70.00%) died in hospital, while 14 cases (14/32, 43.75%) in HIV-negative IC. The crude mortality was significantly different between the two groups (P<0.05). By blood culture, Canidia albicans remained the the most prevalent isolates in all the patients. Clinical manifestation, Candida spp. colonization, etiology and drug susceptibility were also similar between NIC and HIV-negative IC patients (P>0.05).

CONCLUSION

Candidemia in NIC patients tends to occur in those who are much more critically ill, more often admitted in ICU, and more frequently have diabetes mellitus or uncontrolled hyperglycemia and receive invasive mechanical ventilation than HIV-negative IC patients. NIC patients also have poorer prognosis than HIV-negative IC patients. Clinical manifestations, and microbiological characteristics are similar between HIV-negative IC and NIC patients.

[Application of fluoride releasing flowable resin in pit and fissure sealant of children with early enamel caries]

OBJECTIVE

To evaluate the clinical effect of fluoride releasing flowable resin used in treatment of early enamel caries of children compared with conventional sealant.

METHODS

Seventy-six patients, including fifty-two couples of permanent first molars and thirty couples of premolars were selected for this trial. Both sides of all the molars and premolars were diagnosed as early enamel caries based on International Caries Detection and Assessment System (ICDAS) dental caries diagnostic criteria. Using the contralateral control, the teeth were randomly divided into two groups. Molars/premolars in the experimental group were sealed with a fluoride releasing flowable resin; the contralateral molars/premolars were sealed with a conventional fissure sealant as a control group. The retention rate and progress of caries were evaluated at the end of 3, 6, 12 and 24 months.

RESULTS

There was no fissure sealant loss or caries progression in both groups 3 and 6 months after sealing the premolars by fluoride releasing flowable resin or conventional fissure sealants. At the end of 12 and 24 months, only one case of fissure sealant loss was observed in conventional fissure sealant group. There was no statistical significance between the two premolar groups. In the first molar group, fluoride releasing flowable resin showed 100%, 98.08%, 90.38% and 88.46% complete retention at the end of 3, 6, 12 and 24 months, respectively. The conventional fissure sealant retention rates were 96.15%, 92.31%, 76.92% and 73.08% at the corresponding time points. The data at the end of 24 months showed that fluoride releasing flowable resin had significantly higher retention rate than the conventional fissure sealant group (P<0.05). The incidence of caries progression at the end of 6, 12 and 24 months were 1.92%, 5.77% and 7.69%, respectively, in the fluoride releasing flowable resin group. In the conventional fissure sealant group, the incidence was 5.77%, 19.23% and 25.00%, respectively. At the end of 12 and 24 months, more significant decrease of caries progress incidence was observed in the fluoride releasing flowable resin group than in the control group, and there was statistical difference between the two groups (P<0.05).

CONCLUSION

Compared with conventional fissure sealant, using fluoride releasing flowable resin as a fissure sealant in children enamel caries of permanent molars can improve the sealant preservation rate and effectively prevent enamel caries progress.

[Expression of microRNA-155 in inflammatory bowel disease and its clinical significance]

Objective: To explore the expression of microRNA-155 in colonic mucosa and peripheral blood in patients with inflammatory bowel disease(IBD), and to examine the clinical value and significance of microRNA-155 in the diagnosis of IBD. Methods: Quatitative reverse-transcription PCR was performed to detect the expression of microRNA-155 in 20 patients with Crohn disease(CD), 21 patients with ulcerative colitis (UC), 18 patients with IBD type unclassified(IBDU), 25 healthy people(control group), 12 patients with infection colitis and 19 patients with ischemia colitis.Receiver operating characteristic (ROC) curve was performed to analyze the clincal value of microRNA-155 in diagnosis of IBD. Results: The expression of microRNA-155 in colonic mucosa in CD, UC and IBDU group was significantly higher than that in control group(P<0.05). MicroRNA-155 expression was also significantly higher in UC group in comparison to CD group (35.4±3.0 vs 18.6±5.9, P<0.01), IBDU group in comparison to CD group (23.0±3.7 vs 18.6±5.9, P<0.05) and UC group in comparison to IBDU group (35.4±3.0 vs 23.0±3.7, P<0.01). The plasma level of microRNA-155 in UC group (55.6±2.5) and IBDU group (48.1±6.2) was significantly higher than that in control group(P<0.05), while no significant difference in CD group was observed when compared with control group(P>0.05). ROC curve shows an AUC of 0.83 and 95%CI of 0.679-0.986 of microRNA-155 expression in colonic mucosa.The sensitivity and specificity of microRNA-155 expression in colonic mucosa in diagnosis of IBD was 68.4% and 78.6%, respectively. Conclusions: MicroRNA-155 showed high expression in colonic mucosa and peripheral blood in patients with IBD.MicroRNA-155 shows promise as a biomarker in diagnosis of IBD.Furthermore, the aberrant expression indicates that microRNA-155 may be involved in pathogenesis and progression of IBD.

[Research Progress of Sudden Cardiac Death in Forensic Medicine]

Sudden death （SD） is a special kind of death owing to disease, which severely threatening the lives of community population. As the most common type of SD, sudden cardiac death （SCD） has always been a crucial content of identification and research in forensic pathology. This article reviews the research progress from the aspects of epidemiology, morphology, molecular pathology and virtual anatomy of SCD in forensic medicine, so as to provide a reference for the morphological identification, determination of cause of death, and integrated control of this kind of SD.

[Effect of recombinant human growth hormone therapy on metabolic parameters in patients with craniopharyngioma]

Objective: To investigate the effects of recombinant human growth hormone (rhGH) on metabolic parameters in patients with craniopharyngioma surgeries. Methods: Totallys 30 patients with craniopharyngioma were included in this retrospective study. They were divided into growth hormone (GH) group and control group according to whether they received rhGH therapy or not. The following parameters, including body mass index (BMI), weight, waist circumstance, transaminase, fasting blood glucose, lipid profile and high-sensitivity C-reactive protein (hsCRP) were compared after rhGH therapy for 4-6 months. Results: In GH group, patients were 18-46 (30.0±8.8) years old. The duration after craniopharyngioma surgery was (12.9±5.4) years. Before rhGH therapy, they had got sufficient thyroid and glucocorticoid hormone replacement. After rhGH therapy, the body weight decreased from (92.3±20.1) to (87.6 ±14.6) kg (P=0.190), with a reduction of BMI from (30.1±5.9) to (28.2±3.7) kg/m(2) (P=0.120). The waist circumference decreased from (104.4±9.4) cm to (98.8±10.6) cm (P=0.002). Alanine aminotransferase (ALT) decreased from (52±34) to (28±19) U/L (P=0.029), with a reduction of aspartate transaminase (AST) from (46±21) to (33±18) U/L (P=0.035) and γ-glutamyl transpeptadase (GGT) from (59±42) to (29±15) U/L (P=0.02). hsCRP decreased from (5.3±4.9) to (2.3±2.8) mg/L (P=0.006) and triglyceride (TG) decreased from (1.8±0.7) to (1.5±0.6) mmol/L (P=0.028). Fasting blood glucose, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and free fat acid (FFA) were not significantly changed(all P>0.05). In the control group, the above mentioned parameters did not changed significantly during 4-6 months of observational period(all P>0.05). Conclusion: rhGH therapy improves metabolic parameters in patients after craniopharyngioma surgery by decreasing body weight, waist circumstance and fat deposit in liver, as well as lowering TG and hsCRP levels.

Alteration of RNA Splicing by Small-Molecule Inhibitors of the Interaction between NHP2L1 and U4

Splicing is an important eukaryotic mechanism for expanding the transcriptome and proteome, influencing a number of biological processes. Understanding its regulation and identifying small molecules that modulate this process remain a challenge. We developed an assay based on time-resolved fluorescence resonance energy transfer (TR-FRET) to detect the interaction between the protein NHP2L1 and U4 RNA, which are two key components of the spliceosome. We used this assay to identify small molecules that interfere with this interaction in a high-throughput screening (HTS) campaign. Topotecan and other camptothecin derivatives were among the top hits. We confirmed that topotecan disrupts the interaction between NHP2L1 and U4 by binding to U4 and inhibits RNA splicing. Our data reveal new functions of known drugs that could facilitate the development of therapeutic strategies to modify splicing and alter gene function.

Structural and functional insights into the interaction between the Cas family scaffolding protein p130Cas and the focal adhesion-associated protein paxillin

The Cas family scaffolding protein p130Cas is a Src substrate localized in focal adhesions (FAs) and functions in integrin signaling to promote cell motility, invasion, proliferation, and survival. p130Cas targeting to FAs is essential for its tyrosine phosphorylation and downstream signaling. Although the N-terminal SH3 domain is important for p130Cas localization, it has also been reported that the C-terminal region is involved in p130Cas FA targeting. The C-terminal region of p130Cas or Cas family homology domain (CCHD) has been reported to adopt a structure similar to that of the focal adhesion kinase C-terminal focal adhesion-targeting domain. The mechanism by which the CCHD promotes FA targeting of p130Cas, however, remains unclear. In this study, using a calorimetry approach, we identified the first LD motif (LD1) of the FA-associated protein paxillin as the binding partner of the p130Cas CCHD (in a 1:1 stoichiometry with a K_d ∼4.2 μm) and elucidated the structure of the p130Cas CCHD in complex with the paxillin LD1 motif by X-ray crystallography. Of note, a comparison of the CCHD/LD1 complex with a previously solved structure of CCHD in complex with the SH2-containing protein NSP3 revealed that LD1 had almost identical positioning of key hydrophobic and acidic residues relative to NSP3. Because paxillin is one of the key scaffold molecules in FAs, we propose that the interaction between the p130Cas CCHD and the LD1 motif of paxillin plays an important role in p130Cas FA targeting.

Targeting Histone Demethylases in MYC-Driven Neuroblastomas with Ciclopirox

Histone lysine demethylases facilitate the activity of oncogenic transcription factors, including possibly MYC. Here we show that multiple histone demethylases influence the viability and poor prognosis of neuroblastoma cells, where MYC is often overexpressed. We also identified the approved small-molecule antifungal agent ciclopirox as a novel pan-histone demethylase inhibitor. Ciclopirox targeted several histone demethylases, including KDM4B implicated in MYC function. Accordingly, ciclopirox inhibited Myc signaling in parallel with mitochondrial oxidative phosphorylation, resulting in suppression of neuroblastoma cell viability and inhibition of tumor growth associated with an induction of differentiation. Our findings provide new insights into epigenetic regulation of MYC function and suggest a novel pharmacologic basis to target histone demethylases as an indirect MYC-targeting approach for cancer therapy. Cancer Res; 77(17); 4626-38. ©2017 AACR.

Small-molecule inhibition of Wnt signaling abrogates dexamethasone-induced phenotype of primary human trabecular meshwork cells

Trabecular meshwork (TM) cells are the governing regulators of the TM structure. When the functionality of these cells is impaired, the structure of the TM is perturbed which often results in increased ocular hypertension. High intraocular pressure is the most significant risk factor for steroid-induced glaucoma. Dexamethasone (Dex)-induced phenotype of TM cells is widely utilized as a model system to gain insight into mechanisms underlying damaged TM in glaucoma. In this study, to assess the possible role of abnormal Wnt signaling in steroid-induced glaucoma, we analyzed the effects of small-molecule Wnt signaling modulators on Dex-induced expression extracellular matrix proteins of primary human TM cells. While Dex-treated TM cells exhibited increased collagen and fibronectin expression, we found that Wnt signaling inhibitor 3235-0367 suppressed these Dex-induced effects. We therefore propose that Wnt signaling plays an important role in Dex-mediated impairment of TM cell functions. Moreover, the use of small-molecule Wnt signaling inhibitors to treat TM cells may provide an opportunity of restoring TM tissue in steroid-induced glaucoma.

Modulating the wnt signaling pathway with small molecules

Wnt signaling is a critical component during embryonic development and also plays an important role in regulating adult tissue homeostasis. Abnormal activation of Wnt signaling has been implicated in many cancers, while reduced activity of Wnt signaling leads to poor wound healing and structural formations. Thus, extensive efforts have been focused on developing small molecules that have potential to either inhibit or activate the pathway, hoping these molecules can offer leads for novel approaches in treating different human diseases. Many small-molecule inhibitors specifically target various elements, such as Frizzled, Disheveled, Porcupine, or Tankyrase, within the Wnt signaling pathways. These small molecules not only have the potential to be further developed as therapeutic reagents, but they may also be used as chemical probes to dissect the underlying mechanism of the Wnt signaling pathways. Therefore, their respective mechanisms and effective dosages are highly pertinent. Aiming to provide an overview of those molecules in a concise, easy-to-use manner, we summarize and organize the current research on them so that it may be helpful for utilization in different studies.

Autoinhibition of Dishevelled protein regulated by its extreme C terminus plays a distinct role in Wnt/β-catenin and Wnt/planar cell polarity (PCP) signaling pathways

Dishevelled (Dvl) is a key intracellular signaling molecule that mediates the activation of divergent Wnt pathways. It contains three highly conserved domains known as DIX, PDZ, and DEP, the functions of which have been well characterized in β-catenin-dependent canonical and β-catenin-independent noncanonical Wnt signaling. The C-terminal region is also highly conserved from invertebrates to vertebrates. However, its function in regulating the activation of different Wnt signals remains unclear. We reported previously that Dvl conformational change triggered by the highly conserved PDZ-binding C terminus is important for the pathway specificity. Here we provide further evidence demonstrating that binding of the C terminus to the PDZ domain results in Dvl autoinhibition in the Wnt signaling pathways. Therefore, the forced binding of the C terminus to the PDZ domain reduces the activity of Dvl in noncanonical Wnt signaling, whereas obstruction of this interaction releases Dvl autoinhibition, impairs its functional interaction with LRP6 in canonical Wnt signaling, and increases its specificity in noncanonical Wnt signaling, which is closely correlated with an enhanced Dvl membrane localization. Our findings highlight the importance of the C terminus in keeping Dvl in an appropriate autoinhibited state, accessible for regulation by other partners to switch pathway specificity. Particularly, the C-terminally tagged Dvl fusion proteins that have been widely used to study the function and cellular localization of Dvl may not truly represent the wild-type Dvl because those proteins cannot be autoinhibited.

GNAI3: Another Candidate Gene to Screen in Persons with Ocular Albinism

Ocular albinism type 1 (OA), caused by mutations in the OA1 gene, encodes a G-protein coupled receptor, OA1, localized in melanosomal membranes of the retinal pigment epithelium (RPE). This disorder is characterized by both RPE macro-melanosomes and abnormal decussation of ganglion cell axons at the brain's optic chiasm. We demonstrated previously that Oa1 specifically activates Gαi3, which also signals in the Oa1 transduction pathway that regulates melanosomal biogenesis. In this study, we screened the human Gαi3 gene, GNAI3, in DNA samples from 26 patients who had all clinical characteristics of OA but in whom a specific mutation in the OA1 gene had not been found, and in 6 normal control individuals. Using the Agilent HaloPlex Target Enrichment System and next-generation sequencing (NGS) on the Illumina MiSeq platform, we identified 518 variants after rigorous filtering. Many of these variants were corroborated by Sanger sequencing. Overall, 98.8% coverage of the GNAI3 gene was obtained by the HaloPlex amplicons. Of all variants, 6 non-synonymous and 3 synonymous were in exons, 41 in a non-coding exon embedded in the 3' untranslated region (UTR), 6 in the 5' UTR, and 462 in introns. These variants included novel SNVs, insertions, deletions, and a frameshift mutation. All were found in at least one patient but none in control samples. Using computational methods, we modeled the GNAI3 protein and its non-synonymous exonic mutations and determined that several of these may be the cause of disease in the patients studied. Thus, we have identified GNAI3 as a second gene possibly responsible for X-linked ocular albinism.

Drug Repurposing Identifies Inhibitors of Oseltamivir-Resistant Influenza Viruses

The neuraminidase (NA) inhibitor, oseltamivir, is a widely used anti-influenza drug. However, oseltamivir-resistant H1N1 influenza viruses carrying the H275Y NA mutation spontaneously emerged as a result of natural genetic drift and drug treatment. Because H275Y and other potential mutations may generate a future pandemic influenza strain that is oseltamivir-resistant, alternative therapy options are needed. Herein, we show that a structure-based computational method can be used to identify existing drugs that inhibit resistant viruses, thereby providing a first line of pharmaceutical defense against this possible scenario. We identified two drugs, nalidixic acid and dorzolamide, that potently inhibit the NA activity of oseltamivir-resistant H1N1 viruses with the H275Y NA mutation at very low concentrations, but have no effect on wild-type H1N1 NA even at a much higher concentration, suggesting that the oseltamivir-resistance mutation itself caused susceptibility to these drugs.

Structural Basis for the Interaction between Pyk2-FAT Domain and Leupaxin LD Repeats

Proline-rich tyrosine kinase 2 (Pyk2) is a nonreceptor tyrosine kinase and belongs to the focal adhesion kinase (FAK) family. Like FAK, the C-terminal focal adhesion-targeting (FAT) domain of Pyk2 binds to paxillin, a scaffold protein in focal adhesions; however, the interaction between the FAT domain of Pyk2 and paxillin is dynamic and unstable. Leupaxin is another member in the paxillin family and was suggested to be the native binding partner of Pyk2; Pyk2 gene expression is strongly correlated with that of leupaxin in many tissues including primary breast cancer. Here, we report that leupaxin interacts with Pyk2-FAT. Leupaxin has four leucine–aspartate (LD) motifs. The first and third LD motifs of leupaxin preferably target the two LD-binding sites on the Pyk2-FAT domain, respectively. Moreover, the full-length leupaxin binds to Pyk2-FAT as a stable one-to-one complex. Together, we propose that there is an underlying selectivity between leupaxin and paxillin for Pyk2, which may influence the differing behavior of the two proteins at focal adhesion sites.

Structure-based Discovery of Novel Small Molecule Wnt Signaling Inhibitors by Targeting the Cysteine-rich Domain of Frizzled

Frizzled is the earliest discovered glycosylated Wnt protein receptor and is critical for the initiation of Wnt signaling. Antagonizing Frizzled is effective in inhibiting the growth of multiple tumor types. The extracellular N terminus of Frizzled contains a conserved cysteine-rich domain that directly interacts with Wnt ligands. Structure-based virtual screening and cell-based assays were used to identify five small molecules that can inhibit canonical Wnt signaling and have low IC₅₀ values in the micromolar range. NMR experiments confirmed that these compounds specifically bind to the Wnt binding site on the Frizzled8 cysteine-rich domain with submicromolar dissociation constants. Our study confirms the feasibility of targeting the Frizzled cysteine-rich domain as an effective way of regulating canonical Wnt signaling. These small molecules can be further optimized into more potent therapeutic agents for regulating abnormal Wnt signaling by targeting Frizzled.

Conformational change of Dishevelled plays a key regulatory role in the Wnt signaling pathways

The intracellular signaling molecule Dishevelled (Dvl) mediates canonical and non-canonical Wnt signaling via its PDZ domain. Different pathways diverge at this point by a mechanism that remains unclear. Here we show that the peptide-binding pocket of the Dvl PDZ domain can be occupied by Dvl's own highly conserved C-terminus, inducing a closed conformation. In Xenopus, Wnt-regulated convergent extension (CE) is readily affected by Dvl mutants unable to form the closed conformation than by wild-type Dvl. We also demonstrate that while Dvl cooperates with other Wnt pathway elements to activate canonical Wnt signaling, the open conformation of Dvl more effectively activates Jun N-terminal kinase (JNK). These results suggest that together with other players in the Wnt signaling pathway, the conformational change of Dvl regulates Wnt stimulated JNK activity in the non-canonical Wnt signaling.

DOI:http://dx.doi.org/10.7554/eLife.08142.001

The development of an animal embryo depends on a number of signaling pathways that pass information from the outside of the cell to the inside. These pathways include Wnt signaling, which also regulates cell growth. The pathways must be precisely controlled; abnormal Wnt activity has been implicated in several human diseases, ranging from heart disease to cancer.

Wnt signaling is complex, and actually comprises two major pathways: the canonical pathway (which depends on a protein called β-catenin) and the PCP pathway (which doesn't depend on β-catenin). Both pathways are triggered when Wnt molecules bind to receptors on the outside of the cell. These receptors pass the signal into the cell and to a protein called ‘Dishevelled’ (or ‘Dvl’ for short). This protein then passes the signal on through either the canonical or PCP pathway. Nevertheless it is not clear how the Dishevelled protein can direct the signal specifically down either one of these pathways.

Lee et al. now show that the Dishevelled protein can take on at least two different shapes. When it is ‘closed’, one end of the protein is tucked inside a pocket elsewhere on the protein's surface. But when Dishevelled is ‘open’, this end of the protein moves out of this pocket. Further experiments using frogs (called Xenopus, which are commonly used in research) reveal that mutant versions of Dishevelled that were unable to take on the closed form strongly affected an aspect of the frog's development that involves the PCP pathway.

Lee et al. then demonstrate that while Dishevelled cooperates with several other Wnt pathway components to activate the canonical pathway, the open form of Dishevelled activates the PCP pathway. The next challenge following on from this work is to find out how Wnt molecules binding to the receptor trigger the shape change in Dishevelled.

DOI:http://dx.doi.org/10.7554/eLife.08142.002

Association of an inherited genetic variant with vincristine-related peripheral neuropathy in children with acute lymphoblastic leukemia

IMPORTANCE

With cure rates of childhood acute lymphoblastic leukemia (ALL) exceeding 85%, there is a need to mitigate treatment toxicities that can compromise quality of life, including peripheral neuropathy from vincristine treatment.

OBJECTIVE

To identify genetic germline variants associated with the occurrence or severity of vincristine-induced peripheral neuropathy in children with ALL.

DESIGN, SETTING, AND PARTICIPANTS

Genome-wide association study of patients in 1 of 2 prospective clinical trials for childhood ALL that included treatment with 36 to 39 doses of vincristine. Genome-wide single-nucleotide polymorphism (SNP) analysis and vincristine-induced peripheral neuropathy were assessed in 321 patients from whom DNA was available: 222 patients (median age, 6.0 years; range, 0.1-18.8 years) enrolled in 1994-1998 in the St Jude Children's Research Hospital protocol Total XIIIB with toxic effects follow-up through January 2001, and 99 patients (median age, 11.4 years; range, 3.0-23.8 years) enrolled in 2007-2010 in the Children's Oncology Group (COG) protocol AALL0433 with toxic effects follow-up through May 2011. Human leukemia cells and induced pluripotent stem cell neurons were used to assess the effects of lower CEP72 expression on vincristine sensitivity.

EXPOSURE

Treatment with vincristine at a dose of 1.5 or 2.0 mg/m2.

MAIN OUTCOMES AND MEASURES

Vincristine-induced peripheral neuropathy was assessed at clinic visits using National Cancer Institute criteria and prospectively graded as mild (grade 1), moderate (grade 2), serious/disabling (grade 3), or life threatening (grade 4).

RESULTS

Grade 2 to 4 vincristine-induced neuropathy during continuation therapy occurred in 28.8% of patients (64/222) in the St Jude cohort and in 22.2% (22/99) in the COG cohort. A SNP in the promoter region of the CEP72 gene, which encodes a centrosomal protein involved in microtubule formation, had a significant association with vincristine neuropathy (meta-analysis P = 6.3×10(-9)). This SNP had a minor allele frequency of 37% (235/642), with 50 of 321 patients (16%; 95% CI, 11.6%-19.5%) homozygous for the risk allele (TT at rs924607). Among patients with the high-risk CEP72 genotype (TT at rs924607), 28 of 50 (56%; 95% CI, 41.2%-70.0%) developed at least 1 episode of grade 2 to 4 neuropathy, a higher rate than in patients with the CEP72 CC or CT genotypes (58/271 patients [21.4%; 95% CI, 16.9%-26.7%]; P = 2.4×10(-6)). The severity of neuropathy was greater in patients homozygous for the TT genotype compared with patients with the CC or CT genotype (2.4-fold by Poisson regression [P<.0001] and 2.7-fold based on mean grade of neuropathy: 1.23 [95% CI, 0.74-1.72] vs 0.45 [95% CI, 0.3-0.6]; P = .004 by t test). Reducing CEP72 expression in human neurons and leukemia cells increased their sensitivity to vincristine.

CONCLUSIONS AND RELEVANCE

In this preliminary study of children with ALL, an inherited polymorphism in the promoter region of CEP72 was associated with increased risk and severity of vincristine-related peripheral neuropathy. If replicated in additional populations, this finding may provide a basis for safer dosing of this widely prescribed anticancer agent.

Mechanism of polyubiquitination by human anaphase-promoting complex: RING repurposing for ubiquitin chain assembly

Polyubiquitination by E2 and E3 enzymes is a predominant mechanism regulating protein function. Some RING E3s, including anaphase-promoting complex/cyclosome (APC), catalyze polyubiquitination by sequential reactions with two different E2s. An initiating E2 ligates ubiquitin to an E3-bound substrate. Another E2 grows a polyubiquitin chain on the ubiquitin-primed substrate through poorly defined mechanisms. Here we show that human APC's RING domain is repurposed for dual functions in polyubiquitination. The canonical RING surface activates an initiating E2-ubiquitin intermediate for substrate modification. However, APC engages and activates its specialized ubiquitin chain-elongating E2 UBE2S in ways that differ from current paradigms. During chain assembly, a distinct APC11 RING surface helps deliver a substrate-linked ubiquitin to accept another ubiquitin from UBE2S. Our data define mechanisms of APC/UBE2S-mediated polyubiquitination, reveal diverse functions of RING E3s and E2s, and provide a framework for understanding distinctive RING E3 features specifying ubiquitin chain elongation.

Structural and mechanistic insights into the interaction between Pyk2 and paxillin LD motifs

Proline-rich tyrosine kinase 2 (Pyk2) is a member of the focal adhesion kinase (FAK) subfamily of cytoplasmic tyrosine kinases. The C-terminal Pyk2-focal adhesion targeting (FAT) domain binds to paxillin, an adhesion molecule. Paxillin has five leucine-aspartate (LD) motifs (LD1-LD5). Here, we show that the second LD motif of paxillin, LD2, interacts with Pyk2-FAT, similar to the known Pyk2-FAT/LD4 interaction. Both LD motifs can target two ligand binding sites on Pyk2-FAT. Interestingly, they also share similar binding affinity for Pyk2-FAT with preferential association to one site relative to the other. Nevertheless, the LD2-LD4 region of paxillin (paxillin(133-290)) binds to Pyk2-FAT as a 1:1 complex. However, our data suggest that the Pyk2-FAT and paxillin complex is dynamic and it appears to be a mixture of two distinct conformations of paxillin that almost equally compete for Pyk2-FAT binding. These studies provide insight into the underlying selectivity of paxillin for Pyk2 and FAK that may influence the differing behavior of these two closely related kinases in focal adhesion sites.

Catheter-directed thrombolysis in the treatment of acute deep venous thrombosis: a meta-analysis

We performed a meta-analysis for systematic evaluation of the status quo of catheter thrombolysis for the treatment of acute lower limb deep vein thrombosis in China. We searched the China Biomedical bibliographic database (CBM), China National Knowledge Infrastructure (CNKI), Weipu full-text electronic journals, Wanfang full-text database, and Medline (1990 through June 2011) for clinical randomized controlled trials of catheter-directed thrombolysis and superficial venous thrombolysis to compare their efficacies for the treatment of acute deep vein thrombosis. The results were analyzed by using the Cochrane-recommended RevMan 4.2 software package, and the odds ratio (OR) was used as the combined measure of efficacy. The search retrieved 8 randomized controlled trials, and meta-analysis using the total rate of effective treatment as the clinical observation index found that the combined OR for the catheter thrombolysis group versus the superficial venous thrombolysis group was significant (P < 0.01; OR = 11.78; 95% confidence interval = 6.99-19.87). In conclusion, the meta-analysis indicated that catheter thrombolysis was more effective than superficial venous thrombolysis for the treatment of acute deep vein thrombosis in the lower limb in Chinese individuals. However, the included trials were only of medium quality, so more rational and scientific clinical trials are needed to validate this conclusion.

Effects of rehabilitation management on gastric emptying function in older adults with diabetes

The relationship between gastric emptying dysfunction and blood glucose concentration in elderly with type 2 diabetes mellitus was investigated, and the effect of rehabilitation exercise prescription training on gastric emptying in the geriatric diabetic patients was evaluated. A total of 160 older type 2 diabetic adults and 30 cases of non-diabetic patients were studied with regard to the gastric half emptying time (GET1/2) of solid meals radiolabelled with 99mTc. Eighty delayed gastric emptying diabetic patients were randomly divided into 4 four groups: rehabilitation exercise + mosapride group (N = 20), rehabilitation exercise group (N = 20), mosapride group (N = 20), and control group (N = 20). The level of blood glucose was measured every six months in a two-year follow-up. The solid GET1/2 of regulated blood glycemic control patients showed no statistically significant differences from non-diabetic patients (P > 0.05). However, the value for poor blood glycemic control patients exhibited significant statistical differences compared with both non-diabetic (P < 0.01) and regulated blood glycemic control group patients (P < 0.01). It showed that the gastric emptying time improved in the rehabilitation exercise group, mosapride group and rehabilitation exercise group + mosapride group after two years of treatment (P < 0.05). Fasting blood glucose in both rehabilitation exercise group and rehabilitation exercise + mosapride group was significantly decreased. Postprandial blood glucose in the rehabilitation exercise group, mosapride group, rehabilitation exercise group + mosapride group was significantly decreased. High blood glucose level can delay gastric emptying in older type 2 diabetic patients. Gastric emptying and blood glucose control affect each other. It was shown that appropriate rehabilitation exercise combined with prokinetic agent may improve gastric emptying in some geriatric type 2 diabetic patients and help control their blood glucose.

The structural basis of DKK-mediated inhibition of Wnt/LRP signaling

Low-density lipoprotein receptor-related proteins 5 and 6 (LRP5/6) mediate canonical Wnt-β-catenin signaling by forming a complex with the co-receptor Frizzled, which binds to Wnt proteins. Dickkopf (DKK)-related proteins inhibit the Wnt signaling pathway by directly binding to the ectodomains of LRP5/6. However, the mechanism for DKK-mediated antagonism has not been fully understood as of yet. Crystal structures of the LRP6 ectodomain in complex with DKK1, along with mutagenesis studies, provide considerable insights into the molecular basis for DKK-mediated inhibition and Wnt signaling through LRP5/6.

Synthesis of potent dishevelled PDZ domain inhibitors guided by virtual screening and NMR studies

Dishevelled (Dvl) PDZ domains transduce Wnt signals from the membrane-bound receptor Frizzled to the downstream. As abnormal Wnt signaling has been implicated in tumorigenesis, the Dvl PDZ domain is a potential target for small-molecule inhibitors that block Wnt signaling at the Dvl level. We expanded our in silico search to examine the chemical space near previously developed PDZ binders and identified nine additional compounds bind to the Dvl PDZ. We then performed a quantitative structure-activity relationship (QSAR) analysis of these compounds and combined these results with structural studies of the PDZ domain in complex with the compounds to design and synthesize a group of new, further optimized compounds. Two rounds of synthesis and testing yielded a total of six compounds that have greatly improved binding affinity to the Dvl PDZ domain and most potent ones competitively displace Dapper peptide from the PDZ domain. In addition to providing more potent Dvl PDZ domain inhibitors, this study demonstrates that virtual screening and structural studies can be powerful tools in guiding the chemical synthesis hit-to-lead optimization stage during the drug discovery process.

Virtual ligand screening combined with NMR to identify Dvl PDZ domain inhibitors targeting the Wnt signaling

Virtual ligand screening is a powerful technique to identify potential hits of targets and to increase hit rates. Here, we describe how we used this technique combined with NMR (15)N HSQC experiments to obtain small molecules that bind to the PDZ domain of Dvl targeting the Wnt signaling pathway.

Tetraspanins regulate the protrusive activities of cell membrane

Tetraspanins have gained increased attention due to their functional versatility. But the universal cellular mechanism that governs such versatility remains unknown. Herein we present the evidence that tetraspanins CD81 and CD82 regulate the formation and/or development of cell membrane protrusions. We analyzed the ultrastructure of the cells in which a tetraspanin is either overexpressed or ablated using transmission electron microscopy. The numbers of microvilli on the cell surface were counted, and the radii of microvillar tips and the lengths of microvilli were measured. We found that tetraspanin CD81 promotes the microvillus formation and/or extension while tetraspanin CD82 inhibits these events. In addition, CD81 enhances the outward bending of the plasma membrane while CD82 inhibits it. We also found that CD81 and CD82 proteins are localized at microvilli using immunofluorescence. CD82 regulates microvillus morphogenesis likely by altering the plasma membrane curvature and/or the cortical actin cytoskeletal organization. We predict that membrane protrusions embody a common morphological phenotype and cellular mechanism for, at least some if not all, tetraspanins. The differential effects of tetraspanins on microvilli likely lead to the functional diversification of tetraspanins and appear to correlate with their functional propensity.

Pressure dependence of Mn2+ fluorescence in MnS/ZnS core-shell quantum dots

The high pressure photoluminescence spectra of MnS/ZnS core-shells quantum dots were measured using a diamond anvil cell up to 9.4 GPa. Orange emission at 590 nm from the 4T1 --> 6A1 transition of Mn2+ ions was observed. The Mn2+ emission shifted to red with increasing pressure. The experimental pressure coefficient was -48.3 meV/GPa, which is agreement with the calculated value based on the crystal field theory. The redshift is attributed to the increase of crystal field strength and decrease of Racah parameters during compression.

Identification of transmembrane protein 88 (TMEM88) as a dishevelled-binding protein

Wnt signaling pathways are involved in embryonic development and adult tissue maintenance and have been implicated in tumorigenesis. Dishevelled (Dvl/Dsh) protein is one of key components in Wnt signaling and plays essential roles in regulating these pathways through protein-protein interactions. Identifying and characterizing Dvl-binding proteins are key steps toward understanding biological functions. Given that the tripeptide VWV (Val-Trp-Val) binds to the PDZ domain of Dvl, we searched publically available databases to identify proteins containing the VWV motif at the C terminus that could be novel Dvl-binding partners. On the basis of the cellular localization and expression patterns of the candidates, we selected for further study the TMEM88 (target protein transmembrane 88), a two-transmembrane-type protein. The interaction between the PDZ domain of Dvl and the C-terminal tail of TMEM88 was confirmed by using NMR and fluorescence spectroscopy. Furthermore, in HEK293 cells, TMEM88 attenuated the Wnt/β-catenin signaling induced by Wnt-1 ligand in a dose-dependent manner, and TMEM88 knockdown by RNAi increased Wnt activity. In Xenopus, TMEM88 protein is sublocalized at the cell membrane and inhibits Wnt signaling induced by Xdsh but not β-catenin. In addition, TMEM88 protein inhibits the formation of a secondary axis normally induced by Xdsh. The findings suggest that TMEM88 plays a role in regulating Wnt signaling. Indeed, analysis of microarray data revealed that the expression of the Tmem88 gene was strongly correlated with that of Wnt signaling-related genes in embryonic mouse intestines. Together, we propose that TMEM88 associates with Dvl proteins and regulates Wnt signaling in a context-dependent manner.

PDZ domains and their binding partners: structure, specificity, and modification

PDZ domains are abundant protein interaction modules that often recognize short amino acid motifs at the C-termini of target proteins. They regulate multiple biological processes such as transport, ion channel signaling, and other signal transduction systems. This review discusses the structural characterization of PDZ domains and the use of recently emerging technologies such as proteomic arrays and peptide libraries to study the binding properties of PDZ-mediated interactions. Regulatory mechanisms responsible for PDZ-mediated interactions, such as phosphorylation in the PDZ ligands or PDZ domains, are also discussed. A better understanding of PDZ protein-protein interaction networks and regulatory mechanisms will improve our knowledge of many cellular and biological processes.