Synthesis of the Macrolactone Cores of Maltepolides via a Diene-Ene Ring-Closing Metathesis Strategy.

Synthesis of the C19-truncated maltepolide E has been accomplished via a diene-ene ring-closing metathesis (RCM) strategy without damage to the C11-C14 alkenyl epoxy unit. Upon release of the C17-OH group, it attacked at the C14 position with double bond migration and epoxide ring opening to furnish the C19-truncated maltepolides A and B as proposed for the biosynthesis of maltepolides.

Characterization of lodging variation of weedy rice.

Weedy rice (Oryza spp.), one of the most notorious weeds of cultivated rice, evades eradication through stem lodging and seed shattering. Many studies have focused on seed shattering, whereas variations in lodging have received less attention and the underlying mechanisms that cause the differences in lodging between weedy and cultivated rice have not been studied in detail. Here, we compared lodging variation among diverse Chinese weedy rice strains and between weedy rice and co-occurring cultivated rice. The chemical composition of basal stems was determined, and transcriptome and methylome sequencing were used to assess the variation in expression of lodging-related genes. The results showed that the degree of lodging varied between indica-derived weed strains with high lodging levels, which occurred predominantly in southern China, and japonica-derived strains with lower lodging levels, which were found primarily in the north. The more lodging-prone indica weedy rice had a smaller bending stress and lower lignin content than non-lodging accessions. In comparison to co-occurring cultivated rice, there was a lower ratio of cellulose to lignin content in the lodging-prone weedy rice. Variation in DNA methylation of lignin synthesis-related OsSWN1, OsMYBX9, OsPAL1, and Os4CL3 mediated the differences in their expression levels and affected the ratio of cellulose to lignin content. Taken together, our results show that DNA methylation in lignin-related genes regulates variations in stem strength and lodging in weedy rice, and between weed strains and co-occurring cultivated rice.

Effect of Decompressive Craniectomy with Stepwise Decompression of the Intracranial Compartment on Postoperative Neurologic Function, Hemodynamics, and Glasgow Outcome Scale Score of Patients with Severe Traumatic Brain Injury.

BACKGROUND: We assess the effects of standard decompressive craniectomy with stepwise decompression of the intracranial compartment on the postoperative neurologic function, hemodynamics, and Glasgow Outcome Scale (GOS) score of patients with severe traumatic brain injury (sTBI). METHODS: One hundred sTBI patients admitted from July 2017 to February 2019 were enrolled and randomly divided into step and standard groups (n = 50) using a random number table. The standard group received traditional standard decompression during surgery, while the step group underwent multistep decompression during surgery. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were measured immediately after surgery (T0), 3 hours after surgery (T1), 6 hours after surgery (T2), and 12 hours after surgery (T3). The postoperative Glasgow Coma Scale (GCS) score, neurologic function deficit score, and GOS score were evaluated. RESULTS: After treatment, the excellent/good rate of neurologic function improvement and GCS and GOS scores of the step group significantly exceeded those of the standard group (p < 0.05). Compared with the standard group, the HR, SBP, DBP, and MAP decreased significantly in the step group at T1, T2, and T3 (p < 0.05). CONCLUSION: Standard decompressive craniectomy under multistep decompression can markedly improve the neurologic function, hemodynamics, and prognosis of patients.

Cerebrospinal fluid exosomal miR-152-3p predicts the occurrence of subarachnoid haemorrhage and regulates vascular smooth muscle cell dysfunction.

INTRODUCTION: Ruptured intracranial aneurysm (RA) can lead to subarachnoid haemorrhage (SAH). This study was to explore the predictive value of cerebrospinal fluid (CSF) derived exosome miR-152-3p and its regulatory role in the human vascular smooth muscle cells (HVSMCs). MATERIAL AND METHODS: Real-time quantitative polymerase reaction was carried out to detect CSF exosome miR-152-3p in 66 patients with unruptured intracranial aneurysms (UA), 69 patients with RA, and 68 patients with hydrocephalus. Clinical predictive value of SAH occurrence was assessed using receiver operating characteristic curve (ROC) and logistics regression analysis. Cell Counting Kit-8 and Transwell were employed to detect the proliferation and migration of HVSMCs. The binding relationship between miR-152-3p and PTEN was confirmed by the dual-luciferase reporter assay. RESULTS: Compared with hydrocephalus, exosome miR-152-3p was lower in patients with intracranial aneurysms, and among them, RA was lower than in patients with UA (p < 0.001). ROC confirmed that exosome miR-152-3p not only distinguishes patients with UA from patients with hydrocephalus but also predicts SAH in patients with intracranial aneurysms. Logistic regression analysis showed that miR-152-3p (OR = 0.039, 95% CI = 0.015-0.106, p < 0.001) and aneurysm size (OR = 2.701, 95% CI = 1.045-6.890, p = 0.040) were independent predictors of progression for UA to RA. Increased miR-152-3p inhibited the proliferation and migration of HVSMCs. PTEN was the direct target gene of miR-152-3p, which was elevated in CSF-derived exosomes and negatively correlated with miR-152-3p levels. CONCLUSIONS: Our study confirmed that the CSF-derived exosome miR-152-3p was a feasible predictor of SAH and was involved in the dysfunction of HVSMCs.

XPA Enhances Temozolomide Resistance of Glioblastoma Cells by Promoting Nucleotide Excision Repair.

Glioblastoma is the most frequent, as well as aggressive kind of high-grade malignant glioma. Chemoresistance is posing a significant clinical barrier to the efficacy of temozolomide-based glioblastoma treatment. By suppressing xeroderma pigmentosum group A (XPA), a pivotal DNA damage recognition protein implicated in nucleotide excision repair (NER), we devised a novel method to enhance glioblastoma therapy and alleviate temozolomide resistance. On the basis of preliminary assessment, we found that XPA dramatically increased in glioblastoma compared with normal cells and contributed to temozolomide resistance. By constructing XPA stably knockdown cells, we illustrate that XPA protects glioma cells from temozolomide-triggered reproductive cell death, apoptosis, as well as DNA repair. Besides, XPA silencing remarkably enhances temozolomide efficacy in vivo. This study revealed a crucial function of XPA-dependent NER in the resistance of glioma cells to temozolomide.

Predictive value of serum visinin-like protein-1 for early neurologic deterioration and three-month clinical outcome in acute primary basal ganglia hemorrhage: A prospective and observational study.

BACKGROUND: Visinin-like protein 1 (VILIP-1) appears as a biomarker of neuronal injury. We investigated the correlation of serum VILIP-1 concentrations with severity, early neurologic deterioration (END) and functional outcome of intracerebral hemorrhage (ICH). METHODS: In this prospective and observational study, serum VILIP-1 concentrations were quantified in 106 patients with basal ganglia hemorrhage. Univariate and multivariable logistic regression analyses were used to analyze the relationship between serum VILIP-1 concentrations and END plus worse prognosis (modified Rankin Scale score of 3 or greater) at post-injury 3 months. RESULTS: Serum VILIP-1 concentrations of patients were closely correlated with hematoma volume and National Institutes of Health Stroke Scale score. Serum VILIP-1 concentrations were substantially elevated in patients with END or worse 3-month prognosis, as compared to other remainders. Also, serum VILIP-1 concentrations were independently associated with END and worse 3-month prognosis. Under ROC curve analysis, serum VILIP-1 concentrations exhibited marked accuracy for distinguishing patients with the development of END or worse 3-month prognosis. Its predictive ability was in the range of hematoma volume and National Institutes of Health Stroke Scale score. CONCLUSIONS: Serum VILIP-1 may be a good biomarker for assessing hemorrhagic severity and clinical outcomes after ICH.

Predictive Value of Insulin Resistance as Determined by Homeostasis Model Assessment in Acute Ischemic Stroke Patients: A Systematic Review and Meta-Analysis.

Studies on association between homeostasis model assessment of insulin resistance (HOMA-IR) and adverse outcomes have yielded conflicting results in patients with acute ischemic stroke (AIS). This meta-analysis aimed to assess the predictive value of HOMA-IR in AIS patients. Two authors comprehensively searched PubMed and Embase databases until February 28, 2021. All observational studies investigating the association between HOMA-IR and adverse outcomes in AIS patients were included. Outcome measures were poor functional outcome (Modified Rankin Scale≥3), all-cause mortality, stroke recurrence, and neurologic worsening. Seven studies (eight articles) involving 8330 AIS patients were identified. For the highest versus lowest HOMA-IR, the pooled risk ratio (RR) of poor functional outcome was 2.55 (95% CI 1.76-3.70) after adjustment of conventional confounding factors. In addition, elevated HOMA-IR was associated with higher risk of neurologic worsening (RR 1.93; 95% CI 1.15-3.26). However, there were conflicting findings on the association of HOMA-IR with stroke recurrence and all-cause mortality. This meta-analysis confirms that HOMA-IR is significantly associated with an increased risk of poor functional outcome in patients with AIS. However, interpretation of the results of mortality, stroke recurrence, and neurologic worsening should be done with caution due to small number of studies available.

Hydrogen-rich saline alleviates early brain injury through regulating of ER stress and autophagy after experimental subarachnoid hemorrhage.

PURPOSE: Subarachnoid hemorrhage (SAH) is a common complication of cerebral vascular disease. Hydrogen has been reported to alleviate early brain injury (EBI) through oxidative stress injury, reactive oxygen species (ROS), and autophagy. Autophagy is a programmed cell death mechanism that plays a vital role in neuronal cell death after SAH. However, the precise role of autophagy in hydrogen-mediated neuroprotection following SAH has not been confirmed. METHODS: In the present study, the objective was to investigate the neuroprotective effects and potential molecular mechanisms of hydrogen-rich saline in SAH-induced EBI by regulating neural autophagy in the C57BL/6 mice model. Mortality, neurological score, brain water content, ROS, malondialdehyde (MDA), and neuronal death were evaluated. RESULTS: The results show that hydrogen-rich saline treatment markedly increased the survival rate and neurological score, increased neuron survival, downregulated the autophagy protein expression of Beclin-1 and LC3, and endoplasmic reticulum (ER) stress. That indicates that hydrogen-rich saline-mediated inhibition of autophagy and ER stress ameliorate neuronal death after SAH. The neuroprotective capacity of hydrogen-rich saline is partly dependent on the ROS/Nrf2/heme oxygenase-1 (HO-1) signaling pathway. CONCLUSIONS: The results of this study demonstrate that hydrogen-rich saline improves neurological outcomes in mice and reduces neuronal death by protecting against neural autophagy and ER stress.

CircCDC45 promotes the malignant progression of glioblastoma by modulating the miR-485-5p/CSF-1 axis.

BACKGROUND: Glioblastoma (GBM) is characterized by progressive growth and metastasis. Numerous studies claim that the deregulation of circular RNAs (circRNAs) is associated with cancer progression. However, the role of circRNAs in GBM is largely limited. The purpose of this study was to investigate the functions of circCDC45 in GBM and provide a feasible functional mechanism to support its role. METHODS: The expression of circCDC45, miR-485-5p and colony-stimulating factor 1 (CSF-1) mRNA was examined using quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was assessed using cell counting kit - 8 (CCK-8) assay and colony formation assay. Cell migration and cell invasion were monitored using transwell assay. The protein levels of proliferation-related markers and CSF-1 were determined using western blot. The target relationship was predicted using bioinformatics tools and validated using dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Animal models were constructed to verify the role of circCDC45 in vivo. RESULTS: The expression of circCDC45 and CSF-1 was elevated in GBM tissues and cells, while the expression of miR-485-5p was declined. Downregulation of circCDC45 or CSF-1 blocked GBM cell proliferation, invasion and migration as well as tumor growth in vivo. In mechanism, circCDC45 positively regulated the expression of CSF-1 by targeting miR-485-5p. Inhibition of miR-485-5p reversed the biological effects caused by circCDC45 downregulation in GBM cells. CONCLUSION: CircCDC45 promoted the progression of GBM by mediating the miR-485-5p/CSF-1 axis, and circCDC45 might be a promising plasmatic biomarker for GBM diagnosis and treatment.

The Rapid Cytological Process of Grain Determines Early Maturity in Weedy Rice.

Shorter grain-filling period and rapid endosperm development endow weedy rice (WR) with early maturity compared to cultivated rice (CR). However, the role of the cytological features and antioxidative enzyme system during grain development are largely unexplored. We selected four biotypes of WR and their associated cultivated rice (ACR) types from different latitudes to conduct a common garden experiment. The difference in the cytological features of endosperm between WR and ACR was compared by chemical staining, and the cell viability and nuclear morphometry of endosperm cells were observed by optical microscopy. Furthermore, antioxidative enzyme activity was measured during grain filling. Anatomic observation of endosperm shows that the development process of endosperm cell in WR was more rapid and earlier than that in ACR. The percentage of degraded nuclei of WR was 2-83% more than that of ACR. Endosperm cells in WR lost viability 2-6 days earlier than those in ACR. The antioxidant enzyme activity of WR was lower than that of ACR during grain filling. The ability of WR to scavenge reactive oxygen species (ROS) was weaker than that of ACR, which may contribute to the rapid cytological process in the endosperm cells of WR. The rapid cytological process and weaker ability to scavenge ROS in endosperm cells may contribute to early maturity in WR.

Measuring serum melatonin concentrations to predict clinical outcome after aneurysmal subarachnoid hemorrhage.

BACKGROUND: Oxidative stress has a key role in brain injury and melatonin possesses antioxidant effects. We aimed to ascertain the potential relationship between serum melatonin concentrations and functional outcome following aneurysmal subarachnoid hemorrhage (aSAH). METHODS: This prospective and observational study was conducted of 169 aSAH patients. Baseline serum melatonin concentrations were determined. A worse 6-month functional outcome was defined as a Glasgow Outcome Scale score of 1-3. RESULTS: Patients with a worse outcome (56 cases) compared to those with a good outcome (113 cases) exhibited significantly higher concentrations of serum melatonin (P < 0.001). An area under the receiver operating curve of 0.819 was revealed for the prediction of 6-month worse outcome by serum melatonin concentrations. Multiple logistic regression analysis showed an independent association of serum melatonin concentrations with 6-month worse outcome (odds ratio = 1.204). An intimate correlation existed between serum melatonin concentrations and World Federation of Neurological Surgeons subarachnoid hemorrhage scale scores as well as between serum melatonin concentrations and modified Fisher scores (P < 0.001). CONCLUSIONS: Patients with higher serum melatonin concentrations are more likely to have a poor prognosis. Serum melatonin can be considered as an independent predictor of functional outcome after aSAH.

Hydrogen-rich saline alleviates early brain injury through regulating of ER stress and autophagy after experimental subarachnoid hemorrhage

ABSTRACT Purpose: Subarachnoid hemorrhage (SAH) is a common complication of cerebral vascular disease. Hydrogen has been reported to alleviate early brain injury (EBI) through oxidative stress injury, reactive oxygen species (ROS), and autophagy. Autophagy is a programmed cell death mechanism that plays a vital role in neuronal cell death after SAH. However, the precise role of autophagy in hydrogen-mediated neuroprotection following SAH has not been confirmed. Methods: In the present study, the objective was to investigate the neuroprotective effects and potential molecular mechanisms of hydrogen-rich saline in SAH-induced EBI by regulating neural autophagy in the C57BL/6 mice model. Mortality, neurological score, brain water content, ROS, malondialdehyde (MDA), and neuronal death were evaluated. Results: The results show that hydrogen-rich saline treatment markedly increased the survival rate and neurological score, increased neuron survival, downregulated the autophagy protein expression of Beclin-1 and LC3, and endoplasmic reticulum (ER) stress. That indicates that hydrogen-rich saline-mediated inhibition of autophagy and ER stress ameliorate neuronal death after SAH. The neuroprotective capacity of hydrogen-rich saline is partly dependent on the ROS/Nrf2/heme oxygenase-1 (HO-1) signaling pathway. Conclusions: The results of this study demonstrate that hydrogen-rich saline improves neurological outcomes in mice and reduces neuronal death by protecting against neural autophagy and ER stress.

Asymmetric Total Synthesis of the Highly Strained 4ß-Acetoxyprobotryane-9ß,15α-diol.

The first and asymmetric total synthesis of 4ß-acetoxyprobotryane-9ß,15α-diol, containing a rare and highly strained trans-fused bicyclo[3.3.0]octane ring system, has been achieved. The synthetically challenging [6-5-5] tricyclic ring system in the final product was efficiently and diastereoselectively synthesized via an asymmetric rhodium-catalyzed [4 + 2] cycloaddition reaction, followed by a unique benzilic acid type rearrangement under very mild conditions. The seven contiguous stereocenters were installed efficiently and diastereoselectively.

Climate-dependent variation in cold tolerance of weedy rice and rice mediated by OsICE1 promoter methylation.

The mechanisms by which weedy rice (Oryza sativa f. spontanea) has adapted to endure low-temperature stress in northern latitudes remain unresolved. In this study, we assessed cold tolerance of 100 rice varieties and 100 co-occurring weedy rice populations, which were sampled across a broad range of climates in China. A parallel pattern of latitude-dependent variation in cold tolerance was detected in cultivated rice and weedy rice. At the molecular level, differential cold tolerance was strongly correlated with relative expression levels of CBF cold response pathway genes and with methylation levels in the promoter region of OsICE1, a regulator of this pathway. Among all methylated cytosine sites of the OsICE1 promoter, levels of CHG and CHH methylation were found to be significantly correlated with cold tolerance among accessions. Furthermore, within many of the collection locales, weedy rice shared identical or near-identical OsICE1 methylation patterns with co-occurring cultivated rice. These findings provide new insights on the possible roles that methylation variation in the OsICE1 promoter may play in cold tolerance, and they suggest that weedy rice can rapidly acquire cold tolerance via methylation patterns that are shared with co-occurring rice cultivars.

Intramolecular Diels-Alder Cycloaddition Approach toward the cis-Fused Δ5,6-Hexahydroisoindol-1-one Core of Cytochalasins.

Synthesis of the cis-fused Δ5,6-hexahydroisoindol-1-one core of cytochalasins B2-B5, K, Z8, Z9, Z12-Z15, and Z17 has been established starting from an intramolecular Diels-Alder reaction of the amide-tethered (8 E)-1,3,8-nonatriene. The trans-fused 5/6-bicyclic adduct was then subjected to highly stereoselective C9-ß-hydroxylation and epimerization of the C7-α-OH group.

Antitumor Effect and Toxicity of an Albumin-Paclitaxel Nanocarrier System Constructed via Controllable Alkali-Induced Conformational Changes.

Various strategies have been developed to construct albumin nanomaterials via biophysical or chemical changes. In this work, a compound comprising albumin-paclitaxel nanoparticles (NPs-PTX) with a drug loading efficiency of 21% was constructed via manipulation of alkali induced conformation changes and hydrophilic-hydrophobicity transition. The toxicity of two PTX formulations (Taxol and NPs-PTX) in human umbilical vein endothelial cells (HUVECs), RAW264.7, K562, and HepG2 cells, and rats were determined. The half maximal inhibitory concentration (IC50) of Taxol was remarkably lower than that of NPs-PTX. Both PTX formulations promoted cell apoptosis, possibly via mitochondria-dependent (intrinsic) and mitochondria-independent pathways. The effect of PTX formulations (0.5 to 1 mg mL-1) on hemolysis and the median lethal dose (50% mortality, LD50) values of the PTX formulations were significantly different (p < 0.01). Reductions in the number of white blood cells (WBCs) and monocytes (MNCs) and obvious pathological changes in the spleen, thymus, and mesenteric lymph nodes were observed and may have been related to the bone marrow inhibition effect of PTX. The tumor inhibition rate of NPs-PTX (60.8%) was higher than that of Taxol (31.2%) (p < 0.05) when the dose of NPs-PTX (equivalent PTX) was 2.5 times as that of Taxol (30 vs 12 mg kg-1). Taxol is highly toxic, whereas NPs-PTX is moderately toxic. Thus, NPs-PTX has advantages over the commercially available Taxol formulation in terms of low toxicity and increased dosage, indicating NPs-PTX is a better option for safe and effective PTX delivery.

AQP9 promotes astrocytoma cell invasion and motility via the AKT pathway.

The aquaporin (AQP) family, which includes 13 members identified in mammalian cells, is involved in cancer development and progression. AQP9 expression is upregulated in several tumor tissue types. However, the functions of AQP9 in astrocytoma remain elusive. The present study identified that AQP9 was expressed in astrocytoma cells. AQP9 expression was silenced by transfection with small interfering RNAs and increased by transfection with a plasmid containing the AQP9 gene. Using invasion and wound-healing assays, it was revealed that the knockdown of AQP9 suppressed astrocytoma cell invasion and motility, whereas overexpression of AQP9 promoted the invasion and motility of astrocytoma cells. It was further revealed that AQP9 could induce RAC serine/threonine-protein kinase (AKT) activation and decrease E-cadherin expression in astrocytoma cells. Inhibition of the AKT pathway attenuated AQP9-mediated invasion, motility and E-cadherin expression. Taken together, the results of the present study indicated that AQP9 promoted the invasion and motility of cells via the AKT pathway. Therefore, AQP9 may represent a potential target for therapeutic use of astrocytoma.

Feral rice from introgression of weedy rice genes into transgenic herbicide-resistant hybrid-rice progeny.

Pollen-mediated transgenic flow of herbicide resistance occurs bidirectionally between transgenic cultivated rice and weedy rice. The potential risk of weedy traits introgressing into hybrid rice has been underestimated and is poorly understood. In this study, two glufosinate-resistant transgenic rice varieties, hybrid rice (F1), and their succeeding generations (F2-F4) were planted for 3 years in field plots free of weedy rice adjacent to experimental weedy-rice fields. Weedy-rice-like (feral) plants that were both glufosinate-resistant and had red-pericarp seed were initially found only among the F3 generations of the two glufosinate-resistant transgenic hybrid cultivars. The composite fitness (an index based on eight productivity and weediness traits) of the feral progeny was significantly higher than that of the glufosinate-resistant transgenic hybrid (the original female parent of the feral progeny) under monoculture common garden conditions. The hybrid rice progeny segregated into individuals of variable height and extended flowering. The hybrid rice F2 generations had higher outcrossing rates by pollen reception (0.96-1.65%) than their progenitors (0.07-0.98%). The results show that herbicide-resistant weedy rice can rapidly arise by pollen-mediated gene flow from weedy to transgenic hybrid rice, and their segregating pollen-receptive progeny pose a greater agro-ecological risk than transgenic varieties. The safety assessment and management regulations for transgenic hybrid rice should take into account the risk of bidirectional gene flow.

Total Synthesis of Laingolide B Stereoisomers and Assignment of Absolute Configuration.

Total synthesis of (-)-(2 R,9 S)- and (+)-(2 S,9 S)-stereoisomers of laingolide B has been accomplished by using sequential ring-closing metathesis (RCM) and alkene isomerization to construct the macrocyclic trans- N-methyl enamide moiety. The Myers alkylation was used to secure the C2 stereochemistry of the two RCM precursors from a common (9 S)-C3-C9 alkyl iodide. The absolute configuration of laingolide B has been assigned as (2 S,9 R) by comparison of the optical rotation data.

Early flowering and rapid grain filling determine early maturity and escape from harvesting in weedy rice.

BACKGROUND: Early maturity is an important trait that is essential to the survival of weedy rice. To explore the mechanism of early maturity in weedy rice, the reproductive development of a large sample of weedy rice accessions and cultivars was compared in a common garden study. A selected sample of both weedy and cultivated rice was sown at different dates in two years to study in more detail their flowering and grain-filling patterns. RESULTS: The weedy rice from three major cropping regions matured 7-8 days earlier than their associated cultivars. Representative weedy rice accessions planted on conventional sowing dates flowered 3-26 days earlier than cultivars; delayed sowing caused divergence in the flowering regimes in weedy rice. However, regardless of the sowing date, weedy rice filled its grain 7-21 days faster than cultivars in both study years. Vegetative and reproductive traits of weedy and cultivated rice have different patterns of variation with delayed planting. CONCLUSION: Early maturity is an essential factor determining the persistence of weedy rice by contributing to the escape of its seed from being harvested with the rice crop. Both early flowering and shorter grain-filling stages determine early maturity, and flowering is more plastic than grain filling. © 2017 Society of Chemical Industry.