SUCLG1 restricts POLRMT succinylation to enhance mitochondrial biogenesis and leukemia progression.

Mitochondria are cellular powerhouses that generate energy through the electron transport chain (ETC). The mitochondrial genome (mtDNA) encodes essential ETC proteins in a compartmentalized manner, however, the mechanism underlying metabolic regulation of mtDNA function remains unknown. Here, we report that expression of tricarboxylic acid cycle enzyme succinate-CoA ligase SUCLG1 strongly correlates with ETC genes across various TCGA cancer transcriptomes. Mechanistically, SUCLG1 restricts succinyl-CoA levels to suppress the succinylation of mitochondrial RNA polymerase (POLRMT). Lysine 622 succinylation disrupts the interaction of POLRMT with mtDNA and mitochondrial transcription factors. SUCLG1-mediated POLRMT hyposuccinylation maintains mtDNA transcription, mitochondrial biogenesis, and leukemia cell proliferation. Specifically, leukemia-promoting FMS-like tyrosine kinase 3 (FLT3) mutations modulate nuclear transcription and upregulate SUCLG1 expression to reduce succinyl-CoA and POLRMT succinylation, resulting in enhanced mitobiogenesis. In line, genetic depletion of POLRMT or SUCLG1 significantly delays disease progression in mouse and humanized leukemia models. Importantly, succinyl-CoA level and POLRMT succinylation are downregulated in FLT3-mutated clinical leukemia samples, linking enhanced mitobiogenesis to cancer progression. Together, SUCLG1 connects succinyl-CoA with POLRMT succinylation to modulate mitochondrial function and cancer development.

IL-27 signalling promotes adipocyte thermogenesis and energy expenditure.

Thermogenesis in brown and beige adipose tissue has important roles in maintaining body temperature and countering the development of metabolic disorders such as obesity and type 2 diabetes1,2. Although much is known about commitment and activation of brown and beige adipose tissue, its multiple and abundant immunological factors have not been well characterized3-6. Here we define a critical role of IL-27-IL-27Rα signalling in improving thermogenesis, protecting against diet-induced obesity and ameliorating insulin resistance. Mechanistic studies demonstrate that IL-27 directly targets adipocytes, activating p38 MAPK-PGC-1α signalling and stimulating the production of UCP1. Notably, therapeutic administration of IL-27 ameliorated metabolic morbidities in well-established mouse models of obesity. Consistently, individuals with obesity show significantly decreased levels of serum IL-27, which can be restored after bariatric surgery. Collectively, these findings show that IL-27 has an important role in orchestrating metabolic programs, and is a highly promising target for anti-obesity immunotherapy.

A predictive model for therapy failure in chronic myeloid leukemia patients receiving tyrosine kinase inhibitor therapy.

Although tyrosine kinase inhibitor (TKI) therapy has markedly improved the survival of people with chronic-phase chronic myeloid leukemia (CML), 20-30% of people still experienced therapy failure. Data from 1,955 consecutive subjects with chronic-phase CML diagnosed by the European LeukemiaNet (ELN) recommendations from 1 center receiving initial TKI imatinib or a second-generation (2G-) TKI therapy were interrogated to develop a clinical prediction model for TKI therapy failure. This model was subsequently validated in 3,454 subjects from 76 other centers. Using the predictive clinical co-variates associated with TKI therapy failure, we developed a model that stratified subjects into low-, intermediate- and high-risk subgroups with significantly different cumulative incidences of therapy failure (p < 0.001). There was good discrimination and calibration in the external validation dataset, and the performance was consistent with that of the training dataset. Our model had the better prediction discrimination than the Sokal and ELTS scores did, with the greater time-dependent area under the receiver-operator characteristic curve (AUROC) values and a better ability to re-defined the risk of therapy failure. Our model could help physicians estimate the likelihood of initial imatinib or 2G-TKI therapy failure in people with chronic-phase CML.

XIAP-mediated degradation of IFT88 disrupts HSC cilia to stimulate HSC activation and liver fibrosis.

Activation of hepatic stellate cells (HSCs) plays a critical role in liver fibrosis. However, the molecular basis for HSC activation remains poorly understood. Herein, we demonstrate that primary cilia are present on quiescent HSCs but exhibit a significant loss upon HSC activation which correlates with decreased levels of the ciliary protein intraflagellar transport 88 (IFT88). Ift88-knockout mice are more susceptible to chronic carbon tetrachloride-induced liver fibrosis. Mechanistic studies show that the X-linked inhibitor of apoptosis (XIAP) functions as an E3 ubiquitin ligase for IFT88. Transforming growth factor-ß (TGF-ß), a profibrotic factor, enhances XIAP-mediated ubiquitination of IFT88, promoting its proteasomal degradation. Blocking XIAP-mediated IFT88 degradation ablates TGF-ß-induced HSC activation and liver fibrosis. These findings reveal a previously unrecognized role for ciliary homeostasis in regulating HSC activation and identify the XIAP-IFT88 axis as a potential therapeutic target for liver fibrosis.

Safety and efficacy of flumatinib as later-line therapy in patients with chronic myeloid leukemia.

To evaluate the efficacy and safety of flumatinib in the later-line treatment of Chinese patients with Philadelphia chromosome-positive chronic-phase chronic myeloid leukemia (CP-CML previously treated with tyrosine kinase inhibitors (TKIs). Patients with CML-CP were evaluated for the probabilities of responses including complete hematologic response (CHR), cytogenetic response, and molecular response (MR) and adverse events (AEs) after the later-line flumatinib therapy. Of 336 enrolled patients with median age 50 years, median duration of treatment with flumatinib was 11.04 (2-25.23) months. Patients who achieved clinical responses at baseline showed maintenance of CHR, complete cytogenetic response (CCyR)/2-log molecular response (MR2), major molecular response (MMR), and 4-log molecular response or deep molecular response (MR4/DMR) in 100%, 98.9%, 98.6%, and 92.9% patients, respectively. CHR, CCyR/MR2, MMR, and MR4/DMR responses were achieved in 86.4%, 52.7%, 49.6%, and 23.5% patients respectively, which showed the lack of respective clinical responses at baseline. The patients without response at baseline, treated with flumatinib as 2L TKI, having no resistance to prior TKI or only resistance to imatinib, with response to last TKI, and with BCR::ABL ≤10% had higher CCyR/MR2, MMR, or MR4/DMR. The AEs observed during the later-line flumatinib treatment were tolerable and consistent with those reported with the first-line therapy. Flumatinib was effective and safe in patients who are resistant or intolerant to other TKIs. In particular, 2L flumatinib treatment induced high response rates and was more beneficial to patients without previous 2G TKI resistance, thus serving as a probable treatment option for these patients.

ENKD1 promotes CP110 removal through competing with CEP97 to initiate ciliogenesis.

Despite the importance of cilia in cell signaling and motility, the molecular mechanisms regulating cilium formation remain incompletely understood. Herein, we characterize enkurin domain-containing protein 1 (ENKD1) as a novel centrosomal protein that mediates the removal of centriolar coiled-coil protein 110 (CP110) from the mother centriole to promote ciliogenesis. We show that Enkd1 knockout mice possess ciliogenesis defects in multiple organs. Super-resolution microscopy reveals that ENKD1 is a stable component of the centrosome throughout the ciliogenesis process. Simultaneous knockdown of ENKD1 and CP110 significantly reverses the ciliogenesis defects induced by ENKD1 depletion. Protein interaction analysis shows that ENKD1 competes with centrosomal protein 97 (CEP97) in binding to CP110. Depletion of ENKD1 enhances the CP110-CEP97 interaction and detains CP110 at the mother centriole. These findings thus identify ENKD1 as a centrosomal protein and uncover a novel mechanism controlling CP110 removal from the mother centriole for the initiation of ciliogenesis.

Lipid droplets in pathogen infection and host immunity.

As the hub of cellular lipid metabolism, lipid droplets (LDs) have been linked to a variety of biological processes. During pathogen infection, the biogenesis, composition, and functions of LDs are tightly regulated. The accumulation of LDs has been described as a hallmark of pathogen infection and is thought to be driven by pathogens for their own benefit. Recent studies have revealed that LDs and their subsequent lipid mediators contribute to effective immunological responses to pathogen infection by promoting host stress tolerance and reducing toxicity. In this comprehensive review, we delve into the intricate roles of LDs in governing the replication and assembly of a wide spectrum of pathogens within host cells. We also discuss the regulatory function of LDs in host immunity and highlight the potential for targeting LDs for the diagnosis and treatment of infectious diseases.

Upregulation of ENKD1 disrupts cellular homeostasis to promote lymphoma development.

Diffuse large B cell lymphoma (DLBCL) is a common and aggressive form of B cell lymphoma. Approximately 40% of DLBCL patients are incurable despite modern therapeutic approaches. To explore the molecular mechanisms driving the growth and progression of DLBCL, we analyzed genes with differential expression in DLBCL using the Gene Expression Profiling Interactive Analysis database. Enkurin domain-containing protein 1 (ENKD1), a centrosomal protein-encoding gene, was found to be highly expressed in DLBCL samples compared with normal samples. The phylogenetic analysis revealed that ENKD1 is evolutionarily conserved. Depletion of ENKD1 in cultured DLBCL cells induced apoptosis, suppressed cell proliferation, and blocked cell cycle progression in the G2/M phase. Moreover, ENKD1 expression positively correlates with the expression levels of a number of cellular homeostatic regulators, including Sperm-associated antigen 5, a gene encoding an important mitotic regulator. These findings thus demonstrate a critical function for ENKD1 in regulating the cellular homeostasis and suggest a potential value of targeting ENKD1 for the treatment of DLBCL.

Two-Dimensional Pb Square Nets from Bulk (RO)nPb (R = Rare Earth Metals, n = 1,2).

All two-dimensional (2D) materials of group IV elements from Si to Pb are stabilized by carrier doping and interface bonding from substrates except graphene which can be free-standing. The involvement of strong hybrid of bonds, adsorption of exotic atomic species, and the high concentration of crystalline defects are often unavoidable, complicating the measurement of the intrinsic properties. In this work, we report the discovery of seven kinds of hitherto unreported bulk compounds (RO)nPb (R = rare earth metals, n = 1,2), which consist of quasi-2D Pb square nets that are spatially and electronically detached from the [RO]δ+ blocking layers. The band structures of these compounds near Fermi levels are relatively clean and dominantly contributed by Pb, resembling the electron-doped free-standing Pb monolayer. The R2O2Pb compounds are metallic at ambient pressure and become superconductors under high pressures with much enhanced critical fields. In particular, Gd2O2Pb (9.1 µB/Gd) exhibits an interesting bulk response of lattice distortion in conjunction with the emergence of superconductivity and magnetic anomalies at a critical pressure of 10 GPa. Our findings reveal the unexpected facets of 2D Pb sheets that are considerably different from their bulk counterparts and provide an alternative route for exploring 2D properties in bulk materials.

Angioimmunoblastic T-cell lymphoma: Novel recurrent mutations and prognostic biomarkers by cell-free DNA profiling.

Molecular and clinical stratification of patients with angioimmunoblastic T-cell lymphoma (AITL) is unsatisfactory, which hinders the development of personalized therapies. This study aimed to identify molecular biomarkers for AITL based on peripheral cell-free DNA (cfDNA) that could be used to predict prognosis and guide treatment non-invasively. A customized panel containing 46 genes was used to study pretreatment cfDNA and paired tumour tissues in 64 Chinese AITL patients from three clinical centres, and gene mutations in cfDNA and tumour tissue were assessed for concordance (34 paired samples). Then, the association of gene mutations and prognosis was analysed, and a functional enrichment analysis was performed. The sequencing results showed good consistency between cfDNA samples and paired tissue samples. KDM5A, STAT1, FANCM, ERBB4, PIK3R5 and NSD1 were identified as novel recurrent mutations. Mutations in FANCM or combinations of RHOA, KDM5A and FAT1 were associated with poor prognosis. Additionally, functional analysis revealed that RHOAG17 might serve as a predictive biomarker of PD-1 blockade respondence. Our findings confirmed the role of cfDNA as a liquid biopsy in AITL, and revealed novel molecular determinants that can stratify patients and guide treatment options.

Src inhibition induces mitotic arrest associated with chromosomal passenger complex.

The non-receptor tyrosine kinase Src plays a key role in cell division, migration, adhesion, and survival. Src is overactivated in several cancers, where it transmits signals that promote cell survival, mitosis, and other important cancer hallmarks. Src is therefore a promising target in cancer therapy, but the underlying mechanisms are still uncertain. Here we show that Src is highly conserved across different species. Src expression increases during mitosis and is localized to the chromosomal passenger complex. Knockdown or inhibition of Src induces multipolar spindle formation, resulting in abnormal expression of the Aurora B and INCENP components of the chromosomal passenger complex. Molecular mechanism studies have found that Src interacts with and phosphorylates INCENP. This then leads to incorrect chromosome arrangement and segregation, resulting in cell division failure. Herein, Src and chromosomal passenger complex co-localize and Src inhibition impedes mitotic progression by inducing multipolar spindle formation. These findings provide novel insights into the molecular basis for using Src inhibitors to treat cancer.

OGT suppresses S6K1-mediated macrophage inflammation and metabolic disturbance.

Enhanced inflammation is believed to contribute to overnutrition-induced metabolic disturbance. Nutrient flux has also been shown to be essential for immune cell activation. Here, we report an unexpected role of nutrient-sensing O-linked ß-N-acetylglucosamine (O-GlcNAc) signaling in suppressing macrophage proinflammatory activation and preventing diet-induced metabolic dysfunction. Overnutrition stimulates an increase in O-GlcNAc signaling in macrophages. O-GlcNAc signaling is down-regulated during macrophage proinflammatory activation. Suppressing O-GlcNAc signaling by O-GlcNAc transferase (OGT) knockout enhances macrophage proinflammatory polarization, promotes adipose tissue inflammation and lipolysis, increases lipid accumulation in peripheral tissues, and exacerbates tissue-specific and whole-body insulin resistance in high-fat-diet-induced obese mice. OGT inhibits macrophage proinflammatory activation by catalyzing ribosomal protein S6 kinase beta-1 (S6K1) O-GlcNAcylation and suppressing S6K1 phosphorylation and mTORC1 signaling. These findings thus identify macrophage O-GlcNAc signaling as a homeostatic mechanism maintaining whole-body metabolism under overnutrition.

GAD1 alleviates injury-induced optic neurodegeneration by inhibiting retinal ganglion cell apoptosis.

The degeneration of the optic nerve narrows the visual field, eventually causing overall vision loss. This study aimed to identify global protein changes in the retina of optic nerve crushing (ONC) mice and to identify key regulators and pathways involved in injury-induced cell death during the progression of optic neurodegeneration. Label-free quantitative proteomics combined with bioinformatic analysis was performed on retinal protein extracts from ONC and sham-operated mice. Among the 1433 proteins detected, 121 proteins were differentially expressed in the retina of ONC mice. Further bioinformatic analysis showed that various metabolic pathways, including glutamate metabolism and γ-aminobutyric acid (GABA) synthesis, were significantly dysregulated in the injured mouse retinas. Glutamate decarboxylase 1 (GAD1) is the enzyme that converts glutamate into GABA, which was significantly up-regulated during ONC injury. Exogenous GAD1 treatment increased retinal ganglion cell (RGC) survival in the ONC-injured retina. In addition, changes in GAD1 expression were also observed in several other ophthalmic diseases. Vascular endothelial growth factor B (VEGF-B) has previously been reported to protect RGCs from apoptosis and positively regulated the expression of GAD1 in the retina. Notably, combination treatment with GAD1 and VEGF-B also provided strong protection against injury-induced RGC apoptosis. These results suggest that GAD1 expression may serve as an intrinsic protective mechanism that is commonly activated during retinal injury. Targeting GAD1 may serve as a potential strategy to treat optic neurodegenerative diseases.

Low-dose ruxolitinib shows effective in treating myelofibrosis.

The aim of this study was to investigate the effect of low-dose ruxolitinib (daily dose ≤ 10 mg) for the treatment of myelofibrosis (MF). A retrospective analysis was performed on a total of 88 patients with myeloproliferative neoplasm-associated MF (MPN-MF) who were diagnosed and treated in West China Hospital, Sichuan University, China. A total of 44 MPN-MF patients received a low dose of ruxolitinib (daily dose ≤ 10 mg), while another 44 patients received 10-25 mg twice daily. Low-dose ruxolitinib treatment resulted in slow, but gradual spleen response. Compared with baseline, the mean changes in palpable spleen length in the low- and high-dose groups were -26.9 and -49.0% after 12 weeks of treatment, respectively, and -46.7 and -64.1% after 48 weeks of treatment, respectively. In the low dose group, the median myeloproliferative neoplasm symptom assessment form (MPN-SAF) total symptom score (TSS) decreased by 37.8 and 35.9% at the 12 weeks and 48 weeks after treatment, respectively. No statistical difference was observed in MPN-SAF TSS among different dose groups. After 48 weeks of treatment, bone marrow (BM) fibrosis improved in 43.3% (13/30) of evaluated patients and was stable in 56.7% (17/30) patients. In the low-dose treated group, BM fibrosis improved in 50% patients and was stable in remaining 50%. Low-dose ruxolitinib is effective in treating MF.

Substituent Effects on Excited-State Intramolecular Proton Transfer Reaction of 2-Aryloxazoline Derivatives.

Different substituents and benzene ring numbers had significant effects on the fluorescence phenomenon of 2-aryloxazoline derivatives as observed in an experiment. Here, we select five 2-aryloxazoline derivatives with different substituents and benzene ring numbers (2u, 2ad, 2af, 2ai, and 2ah) to analyze the effects on the fluorescence phenomena. For 2ad, 2ah, and 2ai, first, the geometric structures are optimized based on the density functional theory and time-dependent density functional theory methods. The analysis of the obtained bond parameters reveals the variation of hydrogen bond interactions from S0 to S1 states. Second, the calculated absorption and emission spectra are consistent with the experimental values, which proves that the theoretical method is feasible. Finally, through the analysis of the infrared vibrational spectrum, reduced density gradient isosurfaces, frontier molecular orbitals, and potential energy curves, the strengthening mechanism of the hydrogen bond interaction and the ability of the excited-state intramolecular proton transfer (ESIPT) reaction to occur are further explained. Since the proton transfer reactions of 2u and 2af occur spontaneously under photoexcitation, they have no stable structures in the S1 state. In conclusion, due to the different substituents, 2u is more prone to the proton transfer reaction than 2ad. For 2af, 2ai, and 2ah with different benzene ring numbers, the ESIPT reaction is more difficult to occur as the number of benzene rings increases. The ability of the ESIPT reaction to occur follows the order 2af → 2ah → 2ai. For 2-aryloxazoline derivatives with different substituents or different benzene ring numbers, the hydrogen bond strengthening mechanism has been authenticated, which promotes the occurrence of the ESIPT reactions.

[Re-evaluation of indications for prenatal diagnosis of advanced pregnant women under the new screening regime].

OBJECTIVE: To assess the value of non-invasive prenatal testing (NIPT) for women with advanced gestational age but normal measurement for nuchal translucency (NT). METHODS: A total of 9371 singleton pregnancies with negative NT screening at early pregnancy were reviewed. Among these, 8627 cases were selected to be screened again by NIPT, and their indications and results were analyzed. The results were compared with those of with other high risk factors and young gestational age. RESULTS: The incidence of fetal aneuploidies increased in women with advanced gestational age and ultrasound soft markers, in particular among those who were negative for NT screening but over the age of 37. The detection rate of pathological or likely pathological copy number variations was 1.88% among women who directly underwent invasive prenatal diagnosis because of the advanced age, but there was no correlation with the increase of age. 0.68% of the women where with negative NT screening and NIPT still need to undergo invasive prenatal diagnosis. CONCLUSION: After NT screening in early pregnancy, NIPT can replace invasive prenatal diagnosis for those below the age of 37, though there is still a possibility of missed detection of pathogenic copy number variation. It is necessary to strengthen ultrasonic monitoring in later period.

Transcriptional regulation of O-GlcNAc homeostasis is disrupted in pancreatic cancer.

Many intracellular proteins are reversibly modified by O-linked GlcNAc (O-GlcNAc), a post-translational modification that dynamically regulates fundamental cellular processes in response to diverse environmental cues. Accumulating evidence indicates that both excess and deficiency of protein O-GlcNAcylation can have deleterious effects on the cell, suggesting that maintenance of O-GlcNAc homeostasis is essential for proper cellular function. However, the mechanisms through which O-GlcNAc homeostasis is maintained in the physiologic state and altered in the disease state have not yet been investigated. Here, we demonstrate the existence of a homeostatic mechanism involving mutual regulation of the O-GlcNAc-cycling enzymes O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) at the transcriptional level. Specifically, we found that OGA promotes Ogt transcription through cooperation with the histone acetyltransferase p300 and transcription factor CCAAT/enhancer-binding protein ß (C/EBPß). To examine the role of mutual regulation of OGT and OGA in the disease state, we analyzed gene expression data from human cancer data sets, which revealed that OGT and OGA expression levels are highly correlated in numerous human cancers, particularly in pancreatic adenocarcinoma. Using a KrasG12D -driven primary mouse pancreatic ductal adenocarcinoma (PDAC) cell line, we found that inhibition of extracellular signal-regulated kinase (ERK) signaling decreases OGA glycosidase activity and reduces OGT mRNA and protein levels, suggesting that ERK signaling may alter O-GlcNAc homeostasis in PDAC by modulating OGA-mediated Ogt transcription. Our study elucidates a transcriptional mechanism that regulates cellular O-GlcNAc homeostasis, which may lay a foundation for exploring O-GlcNAc signaling as a therapeutic target for human disease.

Effect of solvent environment on excited state intramolecular proton transfer in 2-(4-(dimethylamino)phenyl)-3-hydroxy-6,7-dimethoxy-4h-chromen-4-one.

The new ratiometric fluorescent probe 2-(4-(dimethylamino)phenyl)-3-hydroxy-6,7-dimethoxy-4h-chromen-4-one (HOF) monitoring of methanol in biodiesel was discovered experimentally (T. Y. Qin et al., Sens. Actuators, B, 2018, 277, 484-491). But the experimental study did not report the reaction mechanism in detail. In this study, density functional theory (DFT) and time-density functional theory (TDDFT) methods were used to theoretically study the excited-state intramolecular proton transfer (ESIPT) process of the HOF molecule. The molecular structure in the ground state and the excited state was optimized, and the infrared vibrational spectra, the frontier molecular orbitals, the charge transfer, the potential energy curves and the transition-state structures were calculated. The calculated results prove that the solvent polarity has a great influence on the ESIPT reaction of the HOF molecule. As the solvent polarity increased, the intensity of the intramolecular hydrogen bond decreased, and ESIPT was more difficult to occur. This work has studied the mechanism of the ESIPT reaction in more detail, and paved the way for future research on HOF molecules.

CYLD - a deubiquitylase that acts to fine-tune microtubule properties and functions.

Microtubules are dynamic structures that are crucially involved in a variety of cellular activities. The dynamic properties and functions of microtubules are regulated by various factors, such as tubulin isotype composition and microtubule-binding proteins. Initially identified as a deubiquitylase with tumor-suppressing functions, the protein cylindromatosis (CYLD) has recently been revealed to interact with microtubules, modulate microtubule dynamics, and participate in the regulation of cell migration, cell cycle progression, chemotherapeutic drug sensitivity and ciliogenesis. These findings have greatly enriched our understanding of the roles of CYLD in physiological and pathological conditions. Here, we focus on recent literature that shows how CYLD impacts on microtubule properties and functions in various biological processes, and discuss the challenges we face when interpreting results obtained from different experimental systems.