Chemogenetic activation of PVN CRH neurons disrupts the estrous cycle and LH dynamics in female mice.

Introduction: The impact of stress on reproductive function is significant. Hypothalamic paraventricular nucleus (PVN) corticotrophin-releasing hormone (CRH) plays a major role in regulating the stress response. Understanding how the hypothalamic-pituitary-adrenal (HPA) axis and the hypothalamic-pituitary-gonadal (HPG) axis interact is crucial for comprehending how stress can lead to reproductive dysfunction. However, whether stress influences reproductive function via modulating PVN CRH or HPA sequelae is not fully elucidated. Methods: In this study, we investigated the impact of chemogenetic activation of PVN CRH neurons on reproductive function. We chronically and selectively stimulated PVN CRH neurons in female CRH-Cre mice using excitatory designer receptor exclusively activated by designer drugs (DREADDs) viral constructs, which were bilaterally injected into the PVN. The agonist compound-21 (C21) was delivered through the drinking water. We determined the effects of DREADDs activation of PVN CRH neurons on the estrous cycles, LH pulse frequency in diestrus and metestrus and LH surge in proestrus mice. The effect of long-term C21 administration on basal corticosterone secretion and the response to acute restraint stress during metestrus was also examined. Additionally, computer simulations of a mathematical model were used to determine the effects of DREADDs activation of PVN CRH neurons, simulating chronic stress, on the physiological parameters examined experimentally. Results: As a result, and consistent with our mathematical model predictions, the length of the estrous cycle was extended, with an increase in the time spent in estrus and metestrus, and a decrease in proestrus and diestrus. Additionally, the frequency of LH pulses during metestrus was decreased, but unaffected during diestrus. The occurrence of the preovulatory LH surge during proestrus was disrupted. The basal level of corticosterone during metestrus was not affected, but the response to acute restraint stress was diminished after long-term C21 application. Discussion: These data suggest that PVN CRH neurons play a functional role in disrupting ovarian cyclicity and the preovulatory LH surge, and that the activity of the GnRH pulse generator remains relatively robust during diestrus but not during metestrus under chronic stress exposure in accordance with our mathematical model predictions.

Impact of hyperglycaemia on complications in patients who had a stroke after thrombolysis.

BACKGROUND: We sought to investigate whether admission hyperglycaemia is associated with complications in patients who had an acute ischaemic stroke (AIS) treated with intravenous recombinant tissue plasminogen activator and, if so, whether complications during hospitalisation modify the effect of hyperglycaemia on 3-month poor outcome after thrombolysis. METHODS: Patients who were diagnosed with AIS after thrombolysis between July 2016 and January 2019 were enrolled in this study. Five prespecified complications, including infections, brain oedema, deep vein thrombosis (DVT), haemorrhagic transformation (HT) and gastrointestinal bleeding, were recorded during hospitalisation. RESULTS: Of 388 patients, 143 (36.86%) presented with hyperglycaemia. Patients with hyperglycaemia were more likely to experience one or more complications than patients without hyperglycaemia. After adjustment for potential confounders, hyperglycaemia was associated with brain oedema (OR 2.39; 95% CI 1.08 to 5.30), HT (OR 2.16, 95% CI 1.06 to 4.41), symptomatic intracerebral haemorrhage (sICH) (OR 7.32, 95% CI 2.35 to 22.80) and gastrointestinal bleeding (OR 3.62; 95% CI 1.93 to 6.80), but was not linked to infections (OR 1.48, 95% CI 0.76 to 2.9) and DVT (OR 0.60, 95% CI 0.23 to 1.5). Additional adjustment for the complications in the clinical outcome analysis, done to assess these complications as an intermediate in the pathway from admission hyperglycaemia to clinical outcome, did not substantially change the model (all p for interaction >0.05). CONCLUSION: Hyperglycaemia is an independent predictor of complications following stroke after thrombolysis, especially for brain oedema, gastrointestinal bleeding, HT and sICH. Complications during hospitalisation did not modify the effect of hyperglycaemia on the poor outcome at 3 months in ischaemic stroke.

Maternal High-Fat Diet Multigenerationally Impairs Hippocampal Synaptic Plasticity and Memory in Male Rat Offspring.

As advances are made in the field of developmental origins of health and disease, there is an emphasis on long-term influence of maternal environmental factors on offspring health. Maternal high-fat diet (HFD) consumption has been suggested to exert detrimental effects on cognitive function in offspring, but whether HFD-dependent brain remodeling can be transmitted to the next generations is still unclear. This study tested the hypothesis that HFD consumption during rat pregnancy and lactation multigenerationally influences male offspring hippocampal synaptic plasticity and cognitive function. We observed that hippocampus-dependent learning and memory was impaired in 3 generations from HFD-fed maternal ancestors (referred as F1-F3), as assessed by novel object recognition and Morris water maze tests. Moreover, maternal HFD exposure also affected electrophysiological and ultrastructure measures of hippocampal synaptic plasticity across generations. We observed that intranasal insulin replacement partially rescued hippocampal synaptic plasticity and cognitive deficits in F3 rats, suggesting central insulin resistance may play an important role in maternal diet-induced neuroplasticity impairment. Furthermore, maternal HFD exposure enhanced the palmitoylation of GluA1 critically involved in long-term potentiation induction, while palmitoylation inhibitor 2-bromopalmitate counteracts GluA1 hyperpalmitoylation and partially abolishes the detrimental effects of maternal diet on learning and memory in F3 offspring. Importantly, maternal HFD-dependent GluA1 hyperpalmitoylation was reversed by insulin replacement. Taken together, our data suggest that maternal HFD exposure multigenerationally influences adult male offspring hippocampal synaptic plasticity and cognitive performance, and central insulin resistance may serve as the cross-talk between maternal diet and cognitive impairment across generations.

Neutrophil-to-lymphocyte ratio, hyperglycemia, and outcomes in ischemic stroke patients treated with intravenous thrombolysis.

INTRODUCTION: Increased neutrophil-to-lymphocyte ratio (NLR) and hyperglycemia on admission are associated with poor outcomes in acute ischemic stroke (AIS) patients. We sought to evaluate the combined effect of increased NLR and hyperglycemia on the prognosis of ischemia stroke treated with intravenous thrombolysis (IVT). METHODS: Patients with acute ischemic stroke receiving IVT treatment were prospectively enrolled. All participants were followed for 3 months. According to the levels of NLR and blood glucose, patients were categorized into four groups: high NLR or nonhigh NLR with or without hyperglycemia. The associations between NLR values with or without hyperglycemia and outcomes of stroke after thrombolysis were assessed by multivariable logistic regression analysis. RESULTS: Among the 381 stroke patients (median age 68 years, 61.68% man) included, 155 (40.68%) had a poor outcome (modified Rankin Scale score 3-6) during 3 months. After multivariate adjustment, high NLR with hyperglycemia increased the risk of 3-month poor outcome (OR = 4.42; 95% CI, 2.13-9.16), early neurological deterioration (END) (OR = 4.81; 95% CI, 2.08-11.12), and 3-month mortality (OR = 6.56; 95% CI, 1.92-22.40). A significant multiplicative interaction of NLR and blood glucose on 3-month poor outcome in ischemic stroke patients after thrombolysis was observed. CONCLUSIONS: Ischemic stroke patients with concurrent high NLR and hyperglycemia increased risks of END, 3-month poor outcome, and mortality after thrombolysis.

Dynamic increase in neutrophil levels predicts parenchymal hemorrhage and function outcome of ischemic stroke with r-tPA thrombolysis.

BACKGROUND: The higher level of neutrophil on admission has been reported to predict worse 3-month outcomes in ischemic stroke patients. Our study was to explore the dynamic changes of neutrophil and lymphocyte after r-tPA thrombolysis of ischemic stroke and the relationship with parenchymal hemorrhage (PH) and 3-month function outcome. METHODS: A total of 208 acute ischemic stroke (AIS) patients with intravenous thrombolysis were included and then received 3-month follow-up in the present study. Blood samples for neutrophil and lymphocyte counts were obtained on admission, at 24 h and at 7 days after r-tPA infusion. The associations of increase in neutrophil, lymphocyte, and neutrophil to lymphocyte ratio (NLR) with PH or 3-month poor outcome were examined by logistic regression. RESULTS: Increasing trends in the neutrophil and NLR were observed in AIS patients after r-tPA treatment. Increased level of neutrophil at 24 h after r-tPA infusion but not that on admission was associated with PH (OR = 2.86, P = 0.029) and 3-month poorer functional outcomes (OR = 2.67, P = 0.009). Moreover, patients were divided into four groups according to the percent change in neutrophil within 24 h following r-tPA treatment, and we found that there was a trend of incremental OR when compared higher increase group with lower ones. CONCLUSIONS: Dynamic increase in neutrophil and NLR after stroke may predict PH and 3-month poor outcome in AIS patients receiving r-tPA treatment. Therefore, neutrophil and NLR may serve as activity markers for PH and 3-month poor prognosis in AIS patients with intravenous thrombolysis.

Photophysical Switching between Aggregation-Induced Phosphorescence and Dual-State Emission by Isomeric Substitution.

It is attractive but highly challenging to achieve controllable regulation of photophysical properties of pure organic luminogens, due to distinct work mechanisms and molecular structures. Here, a strategy to regulate in a controllable way the emission behavior of luminogens is reported, according to which long-lived aggregation-induced emission (AIE) can be switched to short-lived dual-state emission (DSE) by an isomer-based substitution reaction. Three luminogens with sharply different photophysical behaviors, including aggregation-induced phosphorescence and dual-state fluorescence emission, were obtained through a substitution reaction with three isomers. Freely rotating structures are attributed to aggregation-induced phosphorescence behavior, whereas twisted rigidification of the molecule greatly contributes to its dual-state emission phenomenon. This work contributes to the controlled regulation of photophysical behaviors through simple reactions and provides a solid evidence to support the key role of the prohibition of intramolecular rotation in aggregation-induced emission process and molecular design of dual-state emitters.

Rational Design of Dual-State Emission Luminogens with Solvatochromism by Combining a Partially Shared Donor-Acceptor Pattern and Twisted Structures.

We report a general design strategy for a new class of luminogens with dual-state emission (DSEgens) that are brightly emissive in both the solution and solid state, with solvatochromism properties, by constructing a partially shared donor-acceptor pattern based on a twisted molecule. The DSEgens with bright fluorescence emission in both the solid and solution state demonstrate a unique solvatochromism behaviour depending on solvent polarity and thus may have applications in anti-counterfeiting.

Engineering TiO2 supported Pt sub-nanoclusters via introducing variable valence Co ion in high-temperature flame for CO oxidation.

As a typical catalytic reaction model, CO catalytic oxidation has many practical applications in gas purification. TiO2 supported Pt sub-nanoclusters have been prepared by introducing variable valence Co ions into a one step flame spray pyrolysis process. Co2+ was oxidized to Co3+ in the high-temperature flame, and the released electrons were transferred to the surface of Pt and suppressed the aggregation of Pt nanoclusters supported on TiO2. As a result, the average size of Pt nanoclusters reduced from 2.47 nm to 0.72 nm with only 1% Co2+ ion doping. Moreover, due to the presence of Co, surface oxygen species were also affected, and these changes also led to a significant increase in the catalytic activity of CO oxidation. The temperature at 100% conversion was decreased from 120 °C to 70 °C, and the TOF increased by an order of magnitude. In addition, in situ DRIFTS was also used to investigate the cause of the significant increase in activity, and it was shown that adsorbed CO species on Pt could be desorbed more easily because of the electron transfer between Pt and Co species.

Nuclear Localizing Peptide-Conjugated, Redox-Sensitive Polymersomes for Delivering Curcumin and Doxorubicin to Pancreatic Cancer Microtumors.

Improving the therapeutic index of anticancer agents is an enormous challenge. Targeting decreases the side effects of the therapeutic agents by delivering the drugs to the intended destination. Nanocarriers containing the nuclear localizing peptide sequences (NLS) translocate to the cell nuclei. However, the nuclear localization peptides are nonselective and cannot distinguish the malignant cells from the healthy counterparts. In this study, we designed a "masked" NLS peptide which is activated only in the presence of overexpressed matrix metalloproteinase-7 (MMP-7) enzyme in the pancreatic cancer microenvironment. This peptide is conjugated to the surface of redox responsive polymersomes to deliver doxorubicin and curcumin to the pancreatic cancer cell nucleus. We have tested the formulation in both two- and three-dimensional cultures of pancreatic cancer and normal cells. Our studies revealed that the drug-encapsulated polymeric vesicles are significantly more toxic toward the cancer cells (shrinking the spheroids up to 49%) compared to the normal cells (shrinking the spheroids up to 24%). This study can lead to the development of other organelle targeted drug delivery systems for various human malignancies.

Real-time monitoring of conformational transitions of single-molecule histone deacetylase 8 with nanocircuits.

Using single-molecule approaches, we directly observed the dynamic interaction between HDAC8 and various ligands as well as conformational interconversions during the catalytic reaction. Statistical analysis identified key kinetic parameters, demonstrating that the enzymatic activity is highly sensitive to both minor variations in the ligand structures and small synthetic molecules.

Role of the Substrate Specificity-Defining Residues of Human SIRT5 in Modulating the Structural Stability and Inhibitory Features of the Enzyme.

Sirtuins are emerging as the key regulators of metabolism and aging, and their potential activators and inhibitors are being explored as therapeutics for improving health and treating associated diseases. Despite the global structural similarity among all seven isoforms of sirtuins (of which most of them catalyze the deacetylation reaction), SIRT5 is the only isoform that catalyzes the cleavage of negatively charged acylated substrates, and the latter feature appears to be encoded by the presence of Tyr102 and Arg105 residues at the active site pocket of the enzyme. To determine the contributions of the above residues in SIRT5 (vis a vis the corresponding residues of SIRT1) on substrate selectivity, inhibition by EX527 and nicotinamide, secondary structural features and thermal stability of the enzymes, we created single and double mutations (viz. Y102A, R105l, and Y102A/R105I) in SIRT5. The kinetic data revealed that while Y102A mutant enzyme catalyzed both deacetylation and desuccinylation reactions with comparable efficiencies, R105I and Y102A/R105I mutant enzymes favored the deacetylase reaction. Like SIRT1, the nicotinamide inhibition of SIRT5 double mutant (Y102A/R105I) exhibited the mixed non-competitive behavior. On the other hand, the desuccinylation reaction of both wild-type and Y102A mutant enzymes conformed to the competitive inhibition model. The inhibitory potency of EX527 progressively increased from Y102A, R105I, to Y102A/R105 mutant enzymes in SIRT5, but it did not reach to the level obtained with SIRT1. The CD spectroscopic data for the wild-type and mutant enzymes revealed changes in the secondary structural features of the enzymes, and such changes were more pronounced on examining their thermal denaturation patterns. A cumulative account of our experimental data reveal mutual cooperation between Y102 and R105 residues in promoting the desuccinylation versus deacetylation reaction in SIRT5, and the overall catalytic feature of the enzyme is manifested via the mutation induced modulation in the protein structure.

Mechanism of N-Acylthiourea-mediated activation of human histone deacetylase 8 (HDAC8) at molecular and cellular levels.

We reported previously that an N-acylthiourea derivative (TM-2-51) serves as a potent and isozyme-selective activator for human histone deacetylase 8 (HDAC8). To probe the molecular mechanism of the enzyme activation, we performed a detailed account of the steady-state kinetics, thermodynamics, molecular modeling, and cell biology studies. The steady-state kinetic data revealed that TM-2-51 binds to HDAC8 at two sites in a positive cooperative manner. Isothermal titration calorimetric and molecular modeling data conformed to the two-site binding model of the enzyme-activator complex. We evaluated the efficacy of TM-2-51 on SH-SY5Y and BE(2)-C neuroblastoma cells, wherein the HDAC8 expression has been correlated with cellular malignancy. Whereas TM-2-51 selectively induced cell growth inhibition and apoptosis in SH-SY5Y cells, it showed no such effects in BE(2)-C cells, and this discriminatory feature appears to be encoded in the p53 genotype of the above cells. Our mechanistic and cellular studies on HDAC8 activation have the potential to provide insight into the development of novel anticancer drugs.