Bioorthogonal Labeling and Enrichment of Histone Monoaminylation Reveal Its Accumulation and Regulatory Function in Cancer Cell Chromatin.

Histone monoaminylation (i.e., serotonylation and dopaminylation) is an emerging category of epigenetic mark occurring on the fifth glutamine (Q5) residue of H3 N-terminal tail, which plays significant roles in gene transcription. Current analysis of histone monoaminylation is mainly based on site-specific antibodies and mass spectrometry, which either lacks high resolution or is time-consuming. In this study, we report the development of chemical probes for bioorthogonal labeling and enrichment of histone serotonylation and dopaminylation. These probes were successfully applied for the monoaminylation analysis of in vitro biochemical assays, cells, and tissue samples. The enrichment of monoaminylated histones by the probes further confirmed the crosstalk between H3Q5 monoaminylation and H3K4 methylation. Finally, combining the ex vivo and in vitro analyses based on the developed probes, we have shown that both histone serotonylation and dopaminylation are highly enriched in tumor tissues that overexpress transglutaminase 2 (TGM2) and regulate the three-dimensional architecture of cellular chromatin.

Association of the triglyceride-glucose index with all-cause and cardiovascular mortality in patients with cardiometabolic syndrome: a national cohort study.

OBJECTIVE: This study aimed to evaluate the association of triglyceride-glucose (TyG) index with all-cause and cardiovascular mortality risk among patients with cardiometabolic syndrome (CMS). METHODS: We performed a cohort study of 5754 individuals with CMS from the 2001-2018 National Health and Nutrition Examination Survey. The TyG index was calculated as Ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. Multivariate Cox proportional hazards regression models assessed the associations between TyG index and mortality . Non-linear correlations and threshold effects were explored using restricted cubic splines and a two-piecewise Cox proportional hazards model. RESULTS: Over a median follow-up of 107 months, 1201 all-cause deaths occurred, including 398 cardiovascular disease-related deaths. The multivariate Cox proportional hazards regression model showed a positive association between the TyG index and all-cause and cardiovascular mortality. Each one-unit increase in the TyG index was associated with a 16% risk increase in all-cause mortality (HR: 1.16, 95% CI 1.03, 1.31, P = 0.017) and a 39% risk increase in cardiovascular mortality (HR: 1.39, 95% CI 1.14, 1.71, P = 0.001) after adjusting for confounders. The restricted cubic splines revealed a U-shaped association between the TyG index and all-cause (P for nonlinear < 0.001) and cardiovascular mortality (P for nonlinear = 0.044), identifying threshold values (all-cause mortality: 9.104; cardiovascular mortality: 8.758). A TyG index below these thresholds displayed a negative association with all-cause mortality (HR: 0.58, 95% CI 0.38, 0.90, P = 0.015) but not with cardiovascular mortality (HR: 0.39, 95% CI 0.12, 1.27, P = 0.119). Conversely, a TyG index exceeding these thresholds was positively associated with all-cause and cardiovascular mortality (HR: 1.35, 95% CI 1.17, 1.55, P < 0.001; HR: 1.54, 95% CI 1.25, 1.90, P < 0.001, respectively). Notably, a higher TyG index (≥ threshold values) was significantly associated with increased mortality only among individuals aged under 55 compared to those with a lower TyG index (< threshold values). CONCLUSIONS: The TyG index demonstrated a U-shaped correlation with all-cause and cardiovascular mortality in individuals with CMS. The thresholds of 9.104 and 8.758 for all-cause and cardiovascular mortality, respectively, may be used as intervention targets to reduce the risk of premature death and cardiovascular disease.

Wavelength and spin-decoupled metasurface based on single-parameter modulation.

Metasurfaces provide an unprecedented platform for precise and subwavelength-scale modulation of optical phases, leading to innovative advancements in wavefront shaping and holography devices. This study presents a single-layer umbrella-like metasurface capable of multichannel holography, encoded with both polarization and wavelength. By leveraging a unique chiral-assisted strategy, we achieve simultaneous decoupling of wavelength and spin states through single-parameter modulation. This approach circumvents the complex structure designs and multi-parameter adjustments typically required in previous methods. Numerical simulations confirm the effectiveness of this metasurface, demonstrating wavelength- and spin-decoupled phase modulation at 1550 and 980 nm. Furthermore, we successfully demonstrate a four-channel hologram operable in both transmission and reflection modes, showcasing the potential applications of this metasurface in compact functional integration, information encryption, and 3D displays. This work paves the way for the development of multifunctional optical devices with enhanced integration and performance.

Associations between Life's Essential 8 and abdominal aortic calcification among US Adults: a cross-sectional study.

BACKGROUND: Cardiovascular health (CVH) and abdominal aortic calcification (AAC) are closely linked to cardiovascular disease (CVD) and related mortality. However, the relationship between CVH metrics via Life's Essential 8 (LE8) and AAC remains unexplored. METHODS: The study analyzed data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) cohort, which included adults aged 40 or above. The research used the LE8 algorithm to evaluate CVH. Semi-quantitative AAC-24 scoring techniques were employed to assess AAC, categorized into no calcification, mild to moderate calcification, and severe calcification. RESULTS: The primary analysis involved 2,478 participants. Following adjustments for multiple factors, the LE8 score exhibited a significant association with ACC risk (Mild-moderate ACC: 0.87, 95% CI: 0.81,0.93; Severe ACC: 0.77, 95% CI: 0.69,0.87, all P < 0.001), indicating an almost linear dose-response relationship. Compared to the low CVH group, the moderate CVH group showed lower odds ratios (OR) for mild-moderate and severe calcification (OR = 0.78, 95% CI: 0.61-0.99, P = 0.041; OR = 0.68, 95% CI: 0.46-0.99, P = 0.047, respectively). Moreover, the high CVH group demonstrated even lower ORs for mild-moderate and severe calcification (OR = 0.46, 95% CI: 0.31, 0.69, P < 0.001; OR = 0.29, 95% CI: 0.14, 0.59, P = 0.001, respectively). Interactions were found between chronic kidney disease (CKD) condition, history of CVD, marital status and CVH metrics to ACC. Participants without CKD exhibited a more pronounced negative association between the CVH metric and both mild-moderate and severe ACC. Those lacking a history of CVD, and never married/widowed/divorced/separated showed a stronger negative association between the CVH metric and severe ACC. CONCLUSIONS: The novel CVH metrics demonstrated an inverse correlation with the risk of AAC. These findings suggest that embracing improved CVH levels may assist in alleviating the burden of ACC.

Balancing adipocyte production and lipid metabolism to treat obesity-induced diabetes with a novel proteoglycan from Ganoderma lucidum.

Obesity is often accompanied by metabolic disorder and insulin resistance, resulting in type 2 diabetes. Based on previous findings, FYGL, a natural hyperbranched proteoglycan extracted from the G. lucidum fruiting body, can decrease blood glucose and reduce body weight in diabetic mice. In this article, the underlying mechanism of FYGL in ameliorating obesity-induced diabetes was further investigated both in vivo and in vitro. FYGL upregulated expression of metabolic genes related to fatty acid biosynthesis, fatty acid ß-oxidation and thermogenesis; downregulated the expression of insulin resistance-related genes; and significantly increased the number of beige adipocytes in db/db mice. In addition, FYGL inhibited preadipocyte differentiation of 3T3-L1 cells by increasing the expression of FABP-4. FYGL not only promoted fatty acid synthesis but also more significantly promoted triglyceride degradation and metabolism by activating the AMPK signalling pathway, therefore preventing fat accumulation, balancing adipocyte production and lipid metabolism, and regulating metabolic disorders and unhealthy obesity. FYGL could be used as a promising pharmacological agent for the treatment of metabolic disorder-related obesity.

Diverse sequence determinants control human and mouse receptor interacting protein 3 (RIP3) and mixed lineage kinase domain-like (MLKL) interaction in necroptotic signaling.

Receptor interacting protein 3 (RIP3) is a protein kinase essential for TNF-induced necroptosis. Phosphorylation on Ser-227 in human RIP3 (hRIP3) is required for its interaction with human mixed lineage kinase domain-like (MLKL) in the necrosome, a signaling complex induced by TNF stimulation. RIP1 and RIP3 mediate necrosome aggregation leading to the formation of amyloid-like signaling complexes. We found that TNF induces Thr-231 and Ser-232 phosphorylation in mouse RIP3 (mRIP3) and this phosphorylation is required for mRIP3 to interact with mMLKL. Ser-232 in mRIP3 corresponds to Ser-227 in hRIP3, whereas Thr-231 is not conserved in hRIP3. Although the RIP3-MLKL interaction is required for necroptosis in both human and mouse cells, hRIP3 does not interact with mMLKL and mRIP3 cannot bind to hMLKL. The species specificity of the RIP3-MLKL interaction is primarily determined by the sequence differences in the phosphorylation sites and the flanking sequence around the phosphorylation sites in hRIP3 and mRIP3. It appears that the RIP3-MLKL interaction has been selected as an evolutionarily conserved mechanism in mediating necroptosis signaling despite that differing structural and mechanistic bases for this interaction emerged simultaneously in different organisms. In addition, we further revealed that the interaction of RIP3 with MLKL prevented massive abnormal RIP3 aggregation, and therefore should be crucial for formation of the amyloid signaling complex of necrosomes. We also found that the interaction between RIP3 and MLKL is required for the translocation of necrosomes to mitochondria-associated membranes. Our data demonstrate the importance of the RIP3-MLKL interaction in the formation of functional necrosomes and suggest that translocation of necrosomes to mitochondria-associated membranes is essential for necroptosis signaling.

Internet use, income mobility and the expansion of the rural middle-income group: Evidence from China.

The expansion of the rural middle-income group has been a global focus as it contributes to narrowing income gaps and reducing social inequality. Using data from the China Family Panel Studies (CFPS), this study examines the impact of Internet use on the mobility of rural low-income groups to the middle-income group from the perspective of income mobility. Controlling for household and provincial-level variables, the results of this study indicate that Internet use significantly promotes the mobility of rural low-income groups to the middle-income group, thereby facilitating the expansion of the rural middle-income group. These conclusions hold even after conducting endogeneity and robustness tests. Mechanism analysis shows that household entrepreneurship and non-agricultural employment are crucial pathways through which Internet use facilitates the mobility of rural low-income groups to middle-income groups. Further investigation shows that mobility from rural low-income to middle-income groups is more difficult in central-western regions and among those with lower levels of education. Internet use exacerbates the "digital divide" between different areas and education groups. In particular, the effect of Internet use in promoting mobility from rural low-income to middle-income groups is more pronounced in the eastern regions and among those with higher levels of education. The results of this study provide new evidence on the role of Internet use in expanding the rural middle-income group.

Design, Synthesis, and Bioevaluation of Novel NLRP3 Inhibitor with IBD Immunotherapy from the Virtual Screen.

NLRP3, a crucial member of the NLRP family, plays a pivotal role in immune regulation and inflammatory modulation. Here, we report a potent and specific NLRP3 inhibitor Z48 obtained though docking-based virtual screening and structure-activity relationship studies with an IC50 of 0.26 µM in THP-1 cells and 0.21 µM in mouse bone marrow-derived macrophages. Mechanistic studies indicated that Z48 could bind directly to the NLRP3 protein (KD = 1.05 µM), effectively blocking the assembly and activation of the NLRP3 inflammasome, consequently manifesting anti-inflammatory properties. Crucially, with acceptable mouse pharmacokinetic profiles, Z48 demonstrated notable therapeutic efficacy in a mouse model of DSS-induced ulcerative colitis, while displaying no significant therapeutic impact on NLRP3KO mice. In conclusion, this study provided a promising NLRP3 inflammasome inhibitor with novel molecular scaffold, poised for further development as a therapeutic candidate in the treatment of inflammatory bowel disease.

Decimeter-depth and polarization addressable color 3D meta-holography.

Fueled by the rapid advancement of nanofabrication, metasurface has provided unprecedented opportunities for 3D holography. Large depth 3D meta-holography not only greatly increases information storage capacity, but also enables distinguishing of the relative spatial relationship of 3D objects, which has important applications in fields like optical information storage and medical diagnosis. Although the methods based on Fresnel diffraction theory can reconstruct the real depth information of 3D objects, the maximum depth is only 2 mm. Here, we develop a 3D meta-holography based on angular spectrum diffraction theory to break through the depth limit. By developing the angular spectrum diffraction theory into meta-holography, the metasurface structure with independent polarization control is used to create a polarization multiplexing 3D meta-hologram. The fabricated amorphous silicon metasurface increases the depth range by 47.5 times and realizes 0.95 dm depth reconstruction for polarization independent and different color 3D meta-hologram in visible. Such polarization controlled large-depth color meta-holography is expected to open avenue for data storage, display, information security and virtual reality.

Bioorthogonal labeling and enrichment of histone monoaminylation reveal its accumulation and regulatory function in cancer cell chromatin.

Histone monoaminylation ( i . e ., serotonylation and dopaminylation) is an emerging category of epigenetic mark occurring on the fifth glutamine (Q5) residue of H3 N-terminal tail, which plays significant roles in gene transcription. Current analysis of histone monoaminylation is mainly based on site-specific antibodies and mass spectrometry, which either lacks high resolution or is time-consuming. In this study, we report the development of chemical probes for bioorthogonal labeling and enrichment of histone serotonylation and dopaminylation. These probes were successfully applied for the monoaminylation analysis of in vitro biochemical assays, cells, and tissue samples. The enrichment of monoaminylated histones by the probes further confirmed the crosstalk between H3Q5 monoaminylation and H3K4 methylation. Finally, combining the ex vivo and in vitro analyses based on the developed probes, we have shown that both histone serotonylation and dopaminylation are highly enriched in tumor tissues that overexpress transglutaminase 2 (TGM2) and regulate the three-dimensional architecture of cellular chromatin.

Riluzole Enhancing anti-PD-1 Efficacy by Activating cGAS/STING Signaling in Colorectal Cancer.

Colorectal cancer is the second leading cause of cancer mortality in the US. Although immune checkpoint blockade therapies including anti-PD-1/PD-L1 have been successful in treating a subset of colorectal cancer patients, response rates remain low. We have found that riluzole, a well-tolerated FDA-approved oral medicine for treating amyotrophic lateral sclerosis, increased intratumoral CD8+ T cells and suppressed tumor growth of colon cancer cells in syngeneic immune competent mice. Riluzole-mediated tumor suppression was dependent on the presence of CD8+ T cells. Riluzole activates the cytosolic DNA sensing cGAS/STING pathway in colon cancer cells, resulting in increased expression of interferon ß (IFNß) and IFNß-regulated genes including CXCL10. Inhibition of ATM, but not ATR, resulted in a synergistic increase in IFNß expression, suggesting that riluzole induces ATM-mediated damage response that contribute to cGAS/STING activation. Depletion of cGAS or STING significantly attenuated riluzole-induced expression of IFNß and CXCL10 as well as increase of intratumoral CD8+ T cells and suppression of tumor growth. These results indicate that riluzole-mediated tumor infiltration of CD8+ T cells and attenuation of tumor growth is dependent on tumor cell intrinsic STING activation. To determine whether riluzole treatment primes the tumor microenvironment for immune checkpoint modulation, riluzole was combined with anti-PD-1 treatment. This combination showed greater efficacy than either single agent, and strongly suppressed tumor growth in vivo. Taken together, our studies indicate that riluzole activates cGAS/STING-mediated innate immune responses, which might be exploited to sensitize colorectal tumors to anti-PD-1/PD-L1 therapies. .

SIX4 Controls Anti-PD-1 Efficacy by Regulating STING Expression.

The cGAS/STING cytosolic DNA-sensing pathway plays a significant role in antitumor immunity. Expression of STING is tightly regulated and commonly reduced or defective in many types of cancer. We have identified SIX4 as a significant regulator of STING expression in colon cancer cells. We showed that knockout of SIX4 decreased STING expression at the mRNA and protein levels while ectopic expression of SIX4 increased STING expression. Depletion of SIX4 led to attenuated STING activation and downstream signaling. Reexpression of SIX4 or ectopic expression of STING in SIX4 knockout cells reversed the effect. Ectopic expression of SIX4 enhanced DMXAA and cGAMP-induced STING activation and downstream signaling. Importantly, decrease of SIX4 expression substantially decreased tumor infiltration of CD8+ T cells and reduced the efficacy of PD-1 antibodies to diminish tumor growth in immune competent mice in vivo. Finally, analysis of The Cancer Genome Atlas colon cancer dataset indicated that tumors with high SIX4 expression were significantly enriched in the Inflammatory Response pathway. SIX4 expression also correlated with expression of multiple IFN-stimulated genes, inflammatory cytokines, and CD8A. Taken together, our results implicate that SIX4 is a principal regulator of STING expression in colon cancer cells, providing an additional mechanism and genetic marker to predict effective immune checkpoint blockade therapy responses. SIGNIFICANCE: Our studies demonstrate that SIX4 is an important regulator of STING expression, providing a genetic marker or a therapeutic target to predict or enhance immune checkpoint blockade therapy responses in colon cancer.

Modification of titanium orthopedic implants with bioactive glass: a systematic review of in vivo and in vitro studies.

Bioactive glasses (BGs) are ideal biomaterials in the field of bio-restoration due to their excellent biocompatibility. Titanium alloys are widely used as a bone graft substitute material because of their excellent corrosion resistance and mechanical properties; however, their biological inertness makes them prone to clinical failure. Surface modification of titanium alloys with bioactive glass can effectively combine the superior mechanical properties of the substrate with the biological properties of the coating material. In this review, the relevant articles published from 2013 to the present were searched in four databases, namely, Web of Science, PubMed, Embase, and Scopus, and after screening, 49 studies were included. We systematically reviewed the basic information and the study types of the included studies, which comprise in vitro experiments, animal tests, and clinical trials. In addition, we summarized the applied coating technologies, which include pulsed laser deposition (PLD), electrophoretic deposition, dip coating, and magnetron sputtering deposition. The superior biocompatibility of the materials in terms of cytotoxicity, cell activity, hemocompatibility, anti-inflammatory properties, bioactivity, and their good bioactivity in terms of osseointegration, osteogenesis, angiogenesis, and soft tissue adhesion are discussed. We also analyzed the advantages of the existing materials and the prospects for further research. Even though the current research status is not extensive enough, it is still believed that BG-coated Ti implants have great clinical application prospects.

ZIFs derived polyhedron with cobalt oxide nanoparticles as novel nanozyme for the biomimetic catalytic oxidation of glucose and non-enzymatic sensor.

The global prevalence of diabetes makes it a significant work to develop flagship sensors in glucose monitoring technology. Particularly, exploring highly active nanocomposites as biomimetic catalysts for the enzymatic reaction of glucose is extremely attractive in non-enzymatic glucose sensing. Herein, nitrogen-doped hollow carbon nano-polyhedron implanted with Co3O4 nanoparticles (NHCN-Co3O4) was introduced as nanozyme for the catalytic oxidation of glucose. NHCN-Co3O4 was synthesized by a two-step redox carbonization of zeolitic imidazolate frameworks. Morphology and structure characterizations revealed that NHCN-Co3O4 was a rhombic nano-dodecahedron with hollow N-doped carbon frameworks. In the frameworks, well-defined Co3O4 nanoparticles were embedded. With highly porous N-doped graphitization structure and embedded Co3O4, NHCN-Co3O4 displayed a distinguished biomimetic catalysis towards the direct oxidation of glucose at a low onset potential of 0.30 V. The biomimetic catalysis of glucose oxidation at NHCN-Co3O4 was so efficient that a steady-state current signal could be established within 3 s. By using NHCN-Co3O4 as nanozyme, a brilliant non-enzymatic glucose sensor was developed with a very low detection limit of 0.2 µM and broad detection range from 1.0 µM to 32.0 mM. Besides, NHCN-Co3O4 sensor also displayed an effective anti-interference capability towards the simulated interfering species including small biomolecules, amino acids, and chloride ion. Furthermore, notable repeatability, reproducibility and long-term stability were also presented. Finally, the successful blood sugar detection in human serum strongly manifests the possible real application of NHCN-Co3O4 sensor.

A Single-Celled Metasurface for Multipolarization Generation and Wavefront Manipulation.

Due to their unprecedented ability to flexibly manipulate the parameters of light, metasurfaces offer a new approach to integrating multiple functions in a single optical element. In this paper, based on a single-celled metasurface composed of chiral umbrella-shaped metal-insulator-metal (MIM) unit cells, a strategy for simultaneous multiple polarization generation and wavefront shaping is proposed. The unit cells can function as broadband and high-performance polarization-preserving mirrors. In addition, by introducing a chiral-assisted Aharonov-Anandan (AA) geometric phase, the phase profile and phase retardation of two spin-flipped orthogonal circular polarized components can be realized simultaneously and independently with a single-celled metasurface via two irrelevant parameters. Benefiting from this flexible phase manipulation ability, a vectorial hologram generator and metalens array with spatially varying polarizations were demonstrated. This work provides an effective approach to avoid the pixel and efficiency losses caused by the intrinsic symmetry of the PB geometric phase, and it may play an important role in the miniaturization and integration of multipolarization-involved displays, real-time imaging, and spectroscopy systems.

A Systematic Review and Network Meta-Analysis of Biomedical Mg Alloy and Surface Coatings in Orthopedic Application.

Magnesium alloys have great application prospects as ideal bone implant materials. However, their poor corrosion resistance limits their clinical orthopedic application. Surface modification promotes the corrosion resistance of magnesium. Conversion coatings, such as calcium phosphate (Ca-P) coating, microarc oxidation (MAO) treatment, and fluoride (FLU) treatment, have been extensively investigated in in vivo studies. This systematic review and network meta-analysis compared the influence of different conversion coatings on bone repair, material properties, and systemic host response in orthopedic applications. Using the PICOS model, the inclusion criteria for biodegradable magnesium and its alloys were determined for in vivo studies. Four databases were used. The standard and weight mean differences with 95% confidence intervals were used to analyze new bone formation and degradation rate. Network structure and forest plots were created, and ranking probabilities were estimated. The risk of bias and quality of evidence were assessed using SYRCLE, CERQual, and GRADE tools. In the qualitative analysis, 43 studies were selected, and the evaluation of each outcome indicator was not entirely consistent from article to article. In the quantitative analysis, 21 articles were subjected to network meta-analysis, with 16 articles on implant degradation and 8 articles for new bone formation. Additionally, SUCRA indicated that Ca-P coating exhibited the highest corrosion resistance, followed by FLU treatment. MAO demonstrated the best capability for new bone formation, followed by Ca-P coating. Ca-P coating exhibited the highest overall performance. To conclude, coated Mg can promote better new bone formation than bare Mg and has considerable biocompatibility. Ca-P-coated Mg and MAO-coated Mg have the greatest potential to significantly promote corrosion resistance and bone regeneration, respectively. The findings of this study will provide a theoretical basis for the investigation of composite coatings and guidance for the orthopedic application of Mg bone implants.

Nitrogen-doped carbon dodecahedron embedded with cobalt nanoparticles for the direct electro-oxidation of glucose and efficient nonenzymatic glucose sensing.

Developing high-performance sensors for glucose detection is extremely desirable for clinical diagnostics and life sciences. Particularly, it is greatly attractive to exploit composite materials with large surface area, doped heterojunction and non-precious metal as highly active electro-catalysts for nonenzymatic glucose sensing. Herein, we reported a N-doped carbon dodecahedron embedded with Co nanoparticles (Co@NCD) for the direct electro-oxidation of glucose and efficient nonenzymatic glucose detection. Co@NCD was synthesized by the pyrolysis of zeolitic imidazolate framework (ZIF). Field emission scanning electron microscope, high-resolution transmission electron microscope, powder X-ray diffraction, X-ray photoelectron spectroscopy and nitrogen adsorption-desorption experiments were performed to investigate Co@NCD. A well-defined dodecahedron morphology with uniform size and shape was observed. Besides, the original framework was carbonized after pyrolysis leading to a hollow and porous graphite dodecahedron containing N-doped carbon heterojunction. Moreover, Co nanoparticles were evenly distributed into the dodecahedron. With porous structure, N-doped carbon and embedded Co nanoparticles, Co@NCD displayed a notable electro-catalysis towards the direct oxidation of glucose (onset potential: 0.20 V). By using Co@NCD as electro-catalyst, an efficient nonenzymatic glucose sensor was obtained with a rapid amperometric response (within 1 s), low detection limit (0.11 µM) and broad detection range (0.2 µM-12.0 mM). In addition, remarkable selectivity, repeatability, reproducibility and long-term stability were also observed. Finally, Co@NCD prepared sensor was also successfully applied to the detection of glucose in human serum. Our results suggested that ZIF templated method could be an innovative solution for active composite catalysts in biomolecular electro-catalysis and Co@NCD prepared sensor could be a substantial preferable sensing platform for the nonenzymatic glucose detection.

D-galactose induces senescence of glioblastoma cells through YAP-CDK6 pathway.

Treatment of glioblastoma using radiotherapy and chemotherapy has various outcomes, key among them being cellular senescence. However, the molecular mechanisms of this process remain unclear. In the present study, we tested the ability of D-galactose (D-gal), a reducing sugar, to induce senescence in glioblastoma cells. Following pretreatment with D-gal, glioblastoma cell lines (C6 and U87MG) showed typical characteristics of senescence. These included the reduced cell proliferation, hypertrophic morphology, increased senescence-associated ß-galactosidase activity, downregulation of Lamin B1, and upregulation of several senescence-associated genes such as p16, p53, and NF-κB. Furthermore, our results showed that D-gal was more suitable than etoposide (a DNA-damage drug) in inducing senescence of glioblastoma cells. Mechanistically, D-gal inactivated the YAP-CDK6 signaling pathway, while overexpression of YAP or CDK6 could restore D-gal-induced senescence of C6 cells. Finally, metformin, an anti-aging agent, activated the YAP-CDK6 pathway and suppressed D-gal-induced senescence of C6 cells. Taken together, these findings established a new model for analyzing senescence in glioblastoma cells, which occurred through the YAP-CDK6 pathway. This is expected to provide a basis for development of novel therapies for the treatment of glioblastoma.

The MLKL Channel in Necroptosis Is an Octamer Formed by Tetramers in a Dyadic Process.

Oligomerization of the mixed-lineage kinase domain-like protein (MLKL) is essential for its cation channel function in necroptosis. Here we show that the MLKL channel is an octamer comprising two previously identified tetramers most likely in their side-by-side position. Intermolecule disulfide bonds are present in the tetramer but are not required for octamer assembly and necroptosis. MLKL forms oligomers in the necrosome and is then released from the necrosome before or during its membrane translocation. We identified two MLKL mutants that could not oligomerize into octamers, although they formed a tetramer, and also, one MLKL mutant could spontaneously form a disulfide bond-linked octamer. Subsequent analysis revealed that the tetramers fail to translocate to the plasma membrane and that the MLKL octamer formation depends on α-helices 4 and 5. While MLKL could be detected from outside the cells, its N- and C-terminal ends could not be detected, indicating that the MLKL octamer spans across the plasma membrane, leaving its N and C termini inside the cell. These data allowed us to propose a 180° symmetry model of the MLKL octamer and conclude that the fully assembled MLKL octamers, but not the previously described tetramers, act as effectors of necroptosis.

Ppm1b negatively regulates necroptosis through dephosphorylating Rip3.

The auto-phosphorylation of murine receptor-interacting protein 3 (Rip3) on Thr 231 and Ser 232 in the necrosome is required to trigger necroptosis. However, how Rip3 phosphorylation is regulated is still largely unknown. Here we identified protein phosphatase 1B (Ppm1b) as a Rip3 phosphatase and found that Ppm1b restricts necroptosis in two settings: spontaneous necroptosis caused by Rip3 auto-phosphorylation in resting cells, and tumour necrosis factor-α (TNF)-induced necroptosis in cultured cells. We revealed that Ppm1b selectively suppresses necroptosis through the dephosphorylation of Rip3, which then prevents the recruitment of mixed lineage kinase domain-like protein (Mlkl) to the necrosome. We further showed that Ppm1b deficiency (Ppm1b(d/d)) in mice enhanced TNF-induced death in a Rip3-dependent manner, and the role of Ppm1b in inhibiting necroptosis was evidenced by elevated Rip3 phosphorylation and tissue damage in the caecum of TNF-treated Ppm1b(d/d) mice. These data indicate that Ppm1b negatively regulates necroptosis through dephosphorylating Rip3 in vitro and in vivo.