Neurons in visual, somatosensory, and auditory cortex can respond to the termination as well as the onset of a sensory stimulus. In auditory cortex, these off responses may underlie the ability of the auditory system to use sound offsets as cues for perceptual grouping. Off responses have been widely proposed to arise from postinhibitory rebound, but this hypothesis has never been directly tested. We used in vivo whole-cell recordings to measure the synaptic inhibition evoked by sound onset. We find that inhibition is invariably transient, indicating that off responses are not caused by post-inhibitory rebound in auditory cortical neurons. Instead, on and off responses appear to be driven by distinct sets of synapses, because they have distinct frequency tuning and different excitatory-inhibitory balance. Furthermore, an on-on sequence causes complete forward suppression, whereas an off-on sequence causes no suppression at all. We conclude that on and off responses are driven by largely nonoverlapping sets of synaptic inputs.
Biogenesis of lysosome-related organelles complex-1 (BLOC-1) is an eight-subunit complex involved in lysosomal trafficking. Interacting proteins of these subunits expand the understanding of its biological functions. With the implementation of the naïve Bayesian analysis, we found that a human uncharacterized 20 kDa coiled-coil KxDL protein, KXD1, is a BLOS1-interacting protein. In vitro binding assays confirmed the interaction between BLOS1 and KXD1. Mouse KXD1 homolog was widely expressed and absent in Kxd1 knockout (KO) mice. BLOS1 was apparently reduced in Kxd1-KO mice. Mild defects in the melanosomes of the retinal pigment epithelia and in the platelet dense granules of the Kxd1-KO mouse were observed, mimicking a mouse model of mild Hermansky-Pudlak syndrome that affects the biogenesis of lysosome-related organelles.
BLOC-1; KXD1; BLOS1; lysosome-related organelles; Hermansky-Pudlak syndrome
Previous cross-sectional studies suggested a positive association between restless legs syndrome (RLS) and coronary heart disease (CHD). This observation was not confirmed by subsequent prospective studies. However, these prospective studies did not take into account the duration of RLS symptoms. We thus prospectively examined whether RLS was associated with an increased risk of CHD in women who participated in the Nurses’ Health Study taking into account the duration of RLS symptoms.
Methods and Results
A total of 70, 694 women (mean age 67 years) who were free of CHD and stroke at baseline (2002) were followed until 2008. Physician-diagnosed RLS was collected via questionnaire. CHD was defined as nonfatal myocardial infarction or fatal CHD. Women with RLS at baseline had a marginally higher risk of developing CHD (multivariable-adjusted hazard ratio (HR), 1.46; 95% confidence interval (CI), 0.97–2.18) as compared with women without RLS. The risk was dependent on duration of symptoms-0.98 (95% CI, 0.44–2.19) for women with RLS less than three years and 1.72 (95% CI, 1.09–2.73) for women with RLS for three years or longer (P trend=0.03). The multivariable-adjusted HRs of women with RLS for three years or longer were 1.80 (95%CI, 1.07–3.01) for nonfatal myocardial infarction and 1.49 (95%CI, 0.55–4.04) for fatal CHD, relative to women without RLS.
We observed that women with RLS for at least three years had an elevated risk of CHD. These results suggest that RLS or RLS associated conditions may contribute to the etiology of cardiovascular disease.
Restless legs syndrome (Willis Ekbom Disease); coronary heart disease; sleep; prospective cohort study
Growing evidence suggests that type 2 diabetes mellitus (DM) is associated with age-dependent Alzheimer’s disease (AD), the latter of which has even been considered as type 3 diabetes. Several physiopathological features including hyperglycemia, oxidative stress, and dysfunctional insulin signaling relate DM to AD. In this study, high glucose-, oxidative stress-induced neuronal injury and intracerebroventricular-streptozotocin (ICV-STZ) animals as the possible models for diabetes-related AD were employed to investigate the effects of exendin-4 (Ex-4), a long-acting glucagon-like peptide-1 (GLP-1) receptor agonist, on diabetes-associated Alzheimer-like changes as well as the molecular mechanisms involved. Our study demonstrated that GLP-1/Ex-4 could exert a protective effect against reduced viability of PC12 cells caused by high glucose and that this protective effect was mediated via the PI3-kinase pathway. In addition, GLP-1/Ex-4 ameliorated oxidative stress-induced injury in PC12 cells. In rat models, bilateral ICV-STZ administration was used to produce impaired insulin signaling in the brain. Fourteen days following ICV-STZ injection, rats treated with twice-daily Ex-4 had better learning and memory performance in the Morris water maze test compared with rats treated with saline. Additionally, histopathological evaluation confirmed the protective effects of Ex-4 treatment on hippocampal neurons against degeneration. Furthermore, we demonstrated that Ex-4 reversed ICV-STZ-induced tau hyperphosphorylation through downregulation of GSK-3β activity, a key kinase in both DM and AD. Our findings suggests that Ex-4 can protect neurons from diabetes-associated glucose metabolic dysregulation insults in vitro and from ICV-STZ insult in vivo, and that Ex-4 may prove of therapeutic value in the treatment of AD especially DM-related AD.
Alzheimer’s disease; Diabetes mellitus; Exendin-4; Streptozotocin; Tau-protein; Glycogen synthase kinase 3β
Systemic administration of chemotherapy for cancer often has toxic side effects, limiting the doses that can be used in its treatment. In this study, we developed methoxy poly(ethylene glycol)-poly(caprolactone) (MPEG-PCL) micelles loaded with curcumin and doxorubicin (Cur-Dox/MPEG-PCL) that were tolerated by recipient mice and had enhanced antitumor effects and fewer side effects. It was shown that these Cur-Dox/MPEG-PCL micelles could release curcumin and doxorubicin slowly in vitro. The long circulation time of MPEG-PCL micelles and the slow rate of release of curcumin and doxorubicin in vivo may help to maintain plasma concentrations of active drug. We also demonstrated that Cur-Dox/MPEG-PCL had improved antitumor effects both in vivo and in vitro. The mechanism by which Cur-Dox/MPEG-PCL micelles inhibit lung cancer might involve increased apoptosis of tumor cells and inhibition of tumor angiogenesis. We found advantages using Cur-Dox/MPEG-PCL micelles in the treatment of cancer, with Cur-Dox/MPEG-PCL achieving better inhibition of LL/2 lung cancer growth in vivo and in vitro. Our study indicates that Cur-Dox/MPEG-PCL micelles may be an effective treatment strategy for cancer in the future.
methoxy poly(ethylene glycol); poly(caprolactone); curcumin; doxorubicin; micelles; cancer; treatment
Lactate dehydrogenase 5 (LDH-5) is one of the major isoenzymes catalyzing the biochemical process of pyruvate to lactate. The purpose of this study was to investigate the expression of serum LDH-5 and test whether this enzyme is regulated by tumor hypoxia and represents a prognostic marker in patients with Non-Hodgkin’s lymphoma (NHL). In this study, LDH-5 levels were detected using agarose gel electrophoresis in NHL patients (n = 266) and non-NHL controls including benign lymphadenectasis (n = 30) and healthy cohorts (n = 233). We also explored the expression of LDH-5 and hypoxia-inducible factor (HIF) 1α in NHL and benign controls by immunohistochemistry and immunofluorescence staining, respectively. Moreover, the role of LDH-5 in the progression of NHL was assessed by multivariate Cox analyses and Kaplan-Meier survival estimates. Serum concentrations of LDH-5 were significantly higher in NHL patients (9.3%) than in benign patients and healthy controls (7.5% and 7.2%, respectively, P<0.01). Application of LDH-5 detection increased the sensitivity of NHL detection, identifying 53.4% of NHL patients as positive, compared with the measurement of total LDH levels (36.5% sensitivity). LDH-5 concentrations increased with clinical stage, extra-nodal site involvement, and WHO performance status of patients with NHL. Exposure to a hypoxic environment induced the expression of LDH-5 and its overexpression correlated with HIF1α cytoplasmic accumulation in NHL cells. In multivariate analyses, LDH-5 was an independent marker for progression-free survival in patients with NHL (P<0.001). Overall, the expression of LDH-5 was elevated in NHL, showing an association with tumor hypoxia and unfavorable prognosis. Thus, LDH-5 emerges as a promising prognostic predictor for NHL patients.
To prospectively explore the association between non-high-density lipoprotein cholesterol (non-HDLC) and the risks of stroke and its subtypes.
A total of 95,916 participants (18-98 years old; 76,354 men and 19,562 women) from a Chinese urban community who were free of myocardial infarction and stroke at baseline time point (2006-2007) were eligible and enrolled in the study. The serum non-HDLC levels of participants were determined by subtracting the high-density lipoprotein cholesterol (HDLC) from total serum cholesterol. The primary outcome was the first occurrence of stroke, which was diagnosed according to the World Health Organization criteria and classified into three subtypes: ischemic stroke, intracerebral hemorrhage, or subarachnoid hemorrhage. The Cox proportional hazards models were used to estimate risk of stroke and its subtypes.
During the four-year follow-up, we identified 1614 stroke events (1,156 ischemic, 416 intracerebral hemorrhagic and 42 subarachnoid hemorrhagic). Statistical analyses showed that hazard ratios (HR) (95% Confidence Interval: CI) of serum Non-HDLC level for total and subtypes of stroke were: 1.08 (1.03-1.12) (total), 1.10 (1.05-1.16) (ischemic), 1.03 (0.96-1.10) (intracerebral hemorrhage) and 0.83 (0.66-1.05) (subarachnoid hemorrhage). HR for non-HDLC refers to the increase per each 20 mg/dl. For total and ischemic stroke, the risks were significantly higher in the fourth and fifth quintiles of non-HDLC concentrations compared to the first quintile after adjusting the confounding factors (total stroke: 4th quintile HR=1.33 (1.12-1.59); 5th quintile HR = 1.36 (1.15-1.62); ischemic stroke: 4th quintile HR =1.34 (1.09-1.66); 5th quintile HR = 1.53 (1.24-1.88)).
Our data suggest that serum non-HDLC level is an independent risk factor for total and ischemic stroke, and that higher serum non-HDLC concentrations are associated with increased risks for total stroke and ischemic stroke, but not for intracerebral and subarachnoid hemorrhage.
Mild traumatic brain injury (mTBI) leads to long-term cognitive and emotional difficulties and behavioral disturbances, but the diagnosis and treatment of mTBI have historically been hampered by a lack of evidence-based correlates of these clinical manifestations. Unlike moderate and severe TBI, mTBI does not show significant tissue lesions or cavities in the cortex. Moreover, neuroimaging by magnetic resonance imaging or computed tomography is usually negative, suggesting that the damage is beyond the resolution of current structure-based scanning technologies. Therefore, we investigated the morphologies of spared neurons in the mouse cortex after mTBI in a controlled cortical impact injury model. Our results indicate that, although mTBI caused only a mild extent of cell death, it led to extensive dendrite degeneration and synapse reduction in the cortex in this model. This study sheds light on the neuropathologic consequences of mTBI in humans and suggests that neurodegeneration may be a novel target for developing diagnostic methods and therapeutic approaches for mTBI.
Dendrite; mTBI; Neural degeneration; Spine; Synapse
Caffeine consumption has been associated with a reduced risk of Parkinson disease. The association is strong and consistent in men, but uncertain in women, possibly because of an interaction with hormone replacement therapy. We sought to confirm these findings using data on Parkinson disease incidence in the CPS II Nutrition Cohort, a large prospective study of men and women.
We conducted a prospective study of caffeine intake and risk of PD within the Cancer Prevention Study II Nutrition Cohort. Intakes of coffee and other sources of caffeine were assessed at baseline. Incident cases of PD (n = 317; 197 men and 120 women) were confirmed by treating physicians and medical record review. Relative risks (RR) were estimated using proportional hazards models, adjusting for age, smoking and alcohol consumption.
After adjustment for age, smoking and alcohol intake, high caffeine consumption was associated with a reduced risk of PD. The relative risk comparing the 5th to the 1st quintile of caffeine intake was 0.43 (CI: 0.26, 0.71, p-trend = <0.002) in men, and 0.61 (95% CI: 0.34, 1.09; p for trend =0.05) in women. Among women, this association was stronger among never users of hormone replacement therapy (RR=0.32) than among ever users (RR=0.81, p-interaction = 0.15). Consumption of decaffeinated coffee was not associated with PD risk.
Findings from this large prospective study of men and women are consistent with a protective effect of caffeine intake on PD incidence, with an attenuating influence of hormone replacement therapy in women.
Parkinson; epidemiology; coffee; caffeine; tea
Memory impairment is one of the most significant residual deficits following traumatic brain injury (TBI) and is among the most frequent complaints heard from patients and their relatives. It has been reported that the hippocampus is particularly vulnerable to TBI, which results in hippocampus-dependent cognitive impairment. There are different regions in the hippocampus, and each region is composed of different cell types, which might respond differently to TBI. However, regional and cell type-specific neuronal death following TBI is not well described. Here, we examined the distribution of degenerating neurons in the hippocampus of the mouse brain following controlled cortical impact (CCI) and found that the majority of degenerating neurons observed were in the dentate gyrus after moderate (0.5 mm cortical deformation) CCI-TBI. In contrast, there were only a few degenerating neurons observed in the hilus, and we did not observe any degenerating neurons in the CA3 or CA1 regions. Among those degenerating cells in the dentate gyrus, about 80% of them were found in the inner granular neuron layer. Analysis with cell type-specific markers showed that most of the degenerating neurons in the inner granular neuron layer are newborn immature neurons. Further quantitative analysis shows that the number of newborn immature neurons in the dentate gyrus is dramatically decreased in the ipsilateral hemisphere compared with the contralateral side. Collectively, our data demonstrate the selective death of newborn immature neurons in the hippocampal dentate gyrus following moderate injury with CCI in mice. This selective vulnerability of newborn immature dentate neurons may contribute to the persistent impairment of learning and memory post-TBI and provide an innovative target for neuroprotective treatment strategies.
traumatic brain injury; controlled cortical impact; cell death; dentate gyrus; Fluoro-Jade B
Recent evidence shows that traumatic brain injury (TBI) regulates proliferation of neural stem/progenitor cells in the dentate gyrus (DG) of adult hippocampus. There are distinct classes of neural stem/progenitor cells in the adult DG, including quiescent neural progenitors (QNPs), which carry stem cell properties, and their progeny, amplifying neural progenitors (ANPs). The response of each class of progenitors to TBI is not clear. We here used a transgenic reporter Nestin-GFP mouse line, in which QNP and ANP cells are easily visualized and quantified, to determine the targets of the TBI in the DG. We examined changes in proliferation of QNPs and ANPs in the acute phase following TBI and found that QNPs were induced by TBI insult to enter the cell cycle whereas proliferation of ANPs was not significantly affected. These results indicate that different subtypes of neural stem/progenitor cells respond differently to TBI insult. Stem cell activation by the TBI may reflect the induction of innate repair and plasticity mechanisms by the injured brain.
Traumatic brain injury; Neural stem/progenitor; Proliferation; Transgenic mice
Most research on the association between restless legs syndrome (RLS) and depression has involved cross-sectional data. The objective of the present study was to evaluate this issue prospectively among Nurses' Health Study participants. A total of 56,399 women (mean age = 68 years) who were free of depression symptoms at baseline (2002) were followed until 2008. Physician-diagnosed RLS was self-reported. During 300,155 person-years of follow-up, the authors identified 1,268 incident cases of clinical depression (regular use of antidepressant medication and physician-diagnosed depression). Women with RLS at baseline were more likely to develop clinical depression (multivariate-adjusted relative risk (RR) = 1.5, 95% confidence interval (CI): 1.1, 2.1; P = 0.02) than those without RLS. The presence of RLS at baseline was also associated with higher scores on the 10-item Center for Epidemiologic Studies Depression Scale (CESD-10) and the 15-item Geriatric Depression Scale (GDS-15) thereafter. Multivariable-adjusted mean differences were 1.00 (standard error, 0.12) for CESD-10 score and 0.47 (standard error, 0.07) for GDS-15 score between women with RLS and those without RLS (P < 0.0001). In conclusion, women with physician-diagnosed RLS had an increased risk of developing clinical depression and clinically relevant depression symptoms. Further prospective studies using refined approaches to ascertainment of RLS and depression are warranted.
depression; meta-analysis; prospective studies; restless legs syndrome
We sought to assess the quality of life in PD patients before the diagnosis, in comparison to age-matched individuals free of PD, among participants in two large prospective cohorts of men and women. Components of the Short-Form Health Status Survey (SF36) were administered to all participants in 1996 and 2008 in the Health Professionals Follow-up Study (HPFS), and in 1992, 1996, 2000 and 2004 in the Nurses’ Health Study (NHS). We used scores in 7 health-related quality of life-dimensions, that were rated from 1(worst) to 100(best) points. We fitted a multivariate mixed-effect model with repeated measures to estimate the expected decline with age and compared that to the decline observed among PD cases by time to diagnosis. 454 men and 414 women with PD contributed data to the analyses. A decline in physical function in PD patients relative to the whole cohort began approximately 7.5 years prior to diagnosis in women and 3 years prior to diagnosis in men, and continued to decline thereafter with a rate of 2.35 and 1.43 points per year in women and men respectively (p< 0.001 for both). For comparison, the average yearly decline in individuals without PD was 0.42 and 0.23 points per year in women and men respectively. Other measures of quality of life (only available in women) declined in a similar pattern to physical function. In summary, the quality of life in PD patients begins to decline years before the diagnosis.
Parkinson; Progression; Epidemiology; Quality of Life
Luteolin (Lu) is one of the flavonoids with anticancer activity, but its poor water solubility limits its use clinically. In this work, we used monomethoxy poly(ethylene glycol)-poly(e-caprolactone) (MPEG-PCL) micelles to encapsulate Lu by a self-assembly method, creating a water-soluble Lu/MPEG-PCL micelle. These micelles had a mean particle size of 38.6 ± 0.6 nm (polydispersity index = 0.16 ± 0.02), encapsulation efficiency of 98.32% ± 1.12%, and drug loading of 3.93% ± 0.25%. Lu/MPEG-PCL micelles could slowly release Lu in vitro. Encapsulation of Lu in MPEG-PCL micelles improved the half-life (t½; 152.25 ± 49.92 versus [vs] 7.16 ± 1.23 minutes, P = 0.007), area under the curve (0-t) (2914.05 ± 445.17 vs 502.65 ± 140.12 mg/L/minute, P = 0.001), area under the curve (0–∞) (2989.03 ± 433.22 vs 503.81 ± 141.41 mg/L/minute, P = 0.001), and peak concentration (92.70 ± 11.61 vs 38.98 ± 7.73 mg/L, P = 0.003) of Lu when the drug was intravenously administered at a dose of 30 mg/kg in rats. Also, Lu/MPEG-PCL micelles maintained the cytotoxicity of Lu on 4T1 breast cancer cells (IC50 = 6.4 ± 2.30 μg/mL) and C-26 colon carcinoma cells (IC50 = 12.62 ± 2.17 μg/mL) in vitro. These data suggested that encapsulation of Lu into MPEG-PCL micelles created an aqueous formulation of Lu with potential anticancer effect.
luteolin; micelle; MPEG-PCL; cancer therapy
Natural killer (NK) cells can kill tumor cells in a non-MHC-restricted manner. However, cancer cells frequently escape from the attack of NK cells by multiple ways. In this study, we investigated the effect of gefitinib on the interaction between NK cells and lung cancer cells.
51Cr release assay, CD107a assay, and IFN-γ secretion assay were performed to detect the sensitivity of lung cancer cell lines A549 and H1975 to NK cells cytotoxicity in the presence of gefitinib. Human NK cells were co-cultured with A549 and H1975 cell lines in the presence of gefitinib. NKG2D ligands, ULBP1, ULBP2, MICA, and MHC-I on tumor cells, and NKG2D, NKp44 and NKp46 on NK cells were evaluated with flow cytometry. 51Cr release assay was performed when NKG2D antibody were added into the co-culture system. Expressions of stat3 and LC3 I/II on tumor cells were determined with western blot after co-cultured with NK cells. After treated with gefitinib, mannose-6-phosphate receptor (MPR) on H1975 cells was evaluated by flow cytometry. 51Cr release assay were performed when MPR antagonist were used.
Gefitinib increased cytotoxicity of NK cells to human lung cancer H1975 cells with EGFR L858R + T790M mutations, while not in A549 cells with wild type EGFR. Gefitinib could block the immune escape by up-regulating the expression of NKG2D ligands ULBP1, ULBP2 or MICA on tumor cells and NKG2D on NK cells in the co-culture system. Gefitinib and NK cells up-regulated MHC-I expression in A549 while not in H1975 cells. NKG2D antibody blocked the enhanced NK cytotoxicity by gefitinib. The combination of NK cells and gefitinib could significantly down-regulate stat3 expression. Furthermore, NK cells-mediated tumor cell autophagy was observed in A549 cells while not in H1975 cells. Notably, gefitinib increased autophagy and MPR expression in H1975 cells, which improved the sensitivity to NK cell-based immunotherapy.
Gefitinib greatly enhanced NK cell cytotoxicity to lung cancer cells with EGFR L858R + T790M resistance mutation. Combination of EGFR tyrokinase inhibitors and NK cells adoptive immunotherapy may represent a potentially effective strategy for patients with non-small cell lung cancer.
Gefitinib; Natural killer cells; Immunotherapy; EGFR; NSCLC
In the budding yeast Saccharomyces cerevisiae, Rho4 GTPase partially plays a redundant role with Rho3 in the control of polarized growth, as deletion of RHO4 and RHO3 together, but not RHO4 alone, caused lethality and a loss of cell polarity at 30°C. Here, we show that overexpression of the constitutively active rho4Q131L mutant in an rdi1Δ strain caused a severe growth defect and generated large, round, unbudded cells, suggesting that an excess of Rho4 activity could block bud emergence. We also generated four temperature-sensitive rho4-Ts alleles in a rho3Δ rho4Δ strain. These mutants showed growth and morphological defects at 37°C. Interestingly, two rho4-Ts alleles contain mutations that cause amino acid substitutions in the N-terminal region of Rho4. Rho4 possesses a long N-terminal extension that is unique among the six Rho GTPases in the budding yeast but is common in Rho4 homologs in other yeasts and filamentous fungi. We show that the N-terminal extension plays an important role in Rho4 function since rho3Δ rho4Δ61 cells expressing truncated Rho4 lacking amino acids (aa) 1 to 61 exhibited morphological defects at 24°C and a growth defect at 37°C. Furthermore, we show that Rho4 interacts with Bem2, a Rho GTPase-activating protein (RhoGAP) for Cdc42 and Rho1, by yeast two-hybrid, bimolecular fluorescence complementation (BiFC), and glutathione S-transferase (GST) pulldown assays. Bem2 specifically interacts with the GTP-bound form of Rho4, and the interaction is mediated by its RhoGAP domain. Overexpression of BEM2 aggravates the defects of rho3Δ rho4 mutants. These results suggest that Bem2 might be a novel GAP for Rho4.
To determine the role of Toll-like receptor 3 in cardiac dysfunction during polymicrobial sepsis.
controlled animal study
University Research Laboratory
Male C57BL/6, Wild type, Toll-like receptor 3−/−
Myocardial dysfunction is a major consequence of septic shock and contributes to the high mortality of sepsis. Toll-like receptors (TLRs) play a critical role in the pathophysiology of sepsis/septic shock. TLR3 is located in intracellular endosomes and recognizes double stranded RNA. This study examined the role of TLR3 in cardiac dysfunction following cecal ligation and puncture (CLP)-induced sepsis. TLR3 knockout (TLR3−/−, n=12) and age-matched wild type (WT, n=12) mice were subjected to CLP. Cardiac function was measured by echocardiography before and 6 hrs after CLP.
Measurements and results
CLP resulted in significant cardiac dysfunction as evidenced by decreased ejection fraction by 25.7% and fractional shortening by 29.8%, respectively. However, TLR3−/− mice showed a maintenance of cardiac function at pre-CLP levels. Wild type mice showed 50% mortality at 58 hrs and 100% mortality at 154 hrs after CLP. In striking contrast, 70% of TLR3−/− mice survive indefinitely, i.e. >200 hrs. TLR3 deficiency significantly decreased CLP-induced cardiac myocyte apoptosis and attenuated CLP-induced Fas and FasL expression in the myocardium. CLP-activation of TLR4-meidated NF-κB and TRIF-dependent IFN signaling pathways was prevented by TLR3 deficiency. In addition, CLP-increased VCAM-1 and ICAM-1 expression and neutrophil and macrophage sequestration in the myocardium were also attenuated in septic TLR3−/− mice. More significantly, adoptive transfer of WT bone marrow stromal cells to TLR3−/− mice abolished the cardioprotective effect in sepsis.
These data indicate that TLR3 plays a deleterious role in mediating cardiac dysfunction in sepsis. Thus, modulation of TLR3 activity may be useful in preventing cardiac dysfunction in sepsis.
Cardiac function; sepsis; TLR3; apoptosis; neutrophils
Embelin, identified primarily from the Embelia ribes plant, has been shown to be a natural small molecule inhibitor of X-linked inhibitor of apoptosis protein (XIAP). It is also a potent inhibitor of NF-κB activation, which makes it a potentially effective suppressor of tumor cell survival, proliferation, invasion, angiogenesis, and inflammation. However, embelin itself is insoluble in water, which makes it unsuitable for in vivo applications. In this work, we developed a novel micelle system through conjugating embelin to a hydrophilic polymer, polyethylene glycol 3,500 (PEG3.5K) through an aspartic acid bridge. The PEG3.5k-embelin2 (PEG3.5k-EB2) conjugate readily forms micelles in aqueous solutions with a CMC of 0.0205mg/mL. Furthermore, PEG3.5k-EB2 micelles effectively solubilize paclitaxel (PTX), a model hydrophobic drug used in this study. Both drug-free and drug-loaded micelles were small in sizes (20 ~ 30 nm) with low polydispersity indexes. In vitro cytotoxicity studies with several tumor cell lines showed that PEG3.5k-EB2 is comparable to embelin in antitumor activity and synergizes with PTX at much lower doses. Our results suggest that PEG-derivatized embelin may represent a novel and dual-functional carrier to facilitate the in vivo applications of poorly water-soluble anticancer drugs such as PTX.
Adenosine, via activation of A1 receptors on the afferent arteriole (AA), mediates the tubuloglomerular feedback (TGF) mechanism. Angiotensin II and nitric oxide (NO) can modulate the sensitivity of the TGF mechanism. However, the interaction among these substances in regulating the TGF resetting phenomenon has been debated. Studies in isolated perfused AA have shown a biphasic response to accumulating doses of adenosine alone. In the nanomolar range adenosine has a weak contractile effect (7%), whereas vasodilatation is observed at high concentrations. However, a synergistic interaction between the contractile response by adenosine and that of angiotensin II has been demonstrated. Adenosine in low concentrations strongly enhances the response to angiotensin II. At the same time, angiotensin II in physiological concentrations increases significantly the contractile response to adenosine. Moreover, addition of a NO donor (spermine NONOate) to increase NO bioavailability abolished the contractile response from combined application of angiotensin II and adenosine. These mutual modulating effects of adenosine and angiotensin II, and the effect of NO on the response of AA can contribute to the resetting of the TGF sensitivity.
adenosine; angiotensin II; tubuloglomerular feedback; afferent arteriole; kidney
The gadE-mdtEF operon encodes a central acid resistance regulator GadE and two multidrug efflux proteins MdtEF. Although transcriptional regulation of gadE in the context of acid resistance under the aerobic growth environment of Escherichia coli has been extensively studied, regulation of the operon under the physiologically relevant environment of anaerobic growth and its effect on the expression of the multidrug efflux proteins MdtEF in the operon has not been disclosed. Our previous study revealed that anaerobic induction of the operon was dependent on ArcA, the response regulator of the ArcBA two-component system, in the M9 glucose minimal medium. However, the detailed regulatory mechanism remains unknown. In this study, we showed that anaerobic activation of mdtEF was driven by the 798 bp unusually long gadE promoter. Deletion of evgA, ydeO, rpoS, and gadX which has been shown to activate the gadE expression during acid stresses under aerobic condition did not have a significant effect on the anaerobic activation of the operon. Rather, anaerobic activation of the operon was largely dependent on the global regulator ArcA and a GTPase MnmE. Under aerobic condition, transcription of gadE was repressed by the global DNA silencer H-NS in M9 minimal medium. Interestingly, under anaerobic condition, while ΔarcA almost completely abolished transcription of gadE-mdtEF, further deletion of hns in ΔarcA mutant restored the transcription of the full-length PgadE-lacZ, and P1- and P3-lacZ fusions, suggesting an antagonistic effect of ArcA on the H-NS mediated repression. Taken together, we conclude that the anaerobic activation of the gadE-mdtEF was primarily mediated by the two-component system ArcBA through antagonizing the H-NS mediated repression.
multidrug efflux pump; acid resistance; anaerobic adaptation; H-NS; ArcBA two-component system; antagonization
Adhesions can form after almost any type of abdominal surgery. Postoperative adhesions can be prevented by improved surgical techniques, such as reducing surgical trauma, preventing ischemia, and avoiding exposure of the peritoneal cavity to foreign materials. Although improved surgical techniques can potentially reduce formation of adhesions, they cannot be eliminated completely. Therefore, finding more effective methods to prevent postoperative adhesions is imperative. Recently, we found that a novel thermosensitive hydrogel, ie, poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC) had the potential to prevent postoperative adhesions. Using the ring-opening polymerization method we prepared a PCEC copolymer which could be dissolved and assembled at 55°C into PCEC micelles with mean size of 25 nm. At body temperature, a solution containing PCEC micelles could convert into a hydrogel. The PCEC copolymer was biodegradable and had low toxicity in vitro and in vivo. We found that most animals in a hydrogel-treated group (n = 10) did not develop adhesions. In contrast, 10 untreated animals developed adhesions that could only be separated by sharp dissection (P < 0.001). The hydrogel could adhere to peritoneal wounds and degraded gradually over 7–9 days, transforming into a viscous fuid that was completely absorbed within 12 days. The injured parietal and visceral peritoneum remesothelialized over about seven and nine days, respectively. This study confirms that PCEC hydrogel has potential application in the prevention of postoperative adhesions.
poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone); thermosensitive; biodegradable; hydrogel; postoperative adhesions
The antimalaria drug chloroquine has been used as an anti-inflammatory agent for treating systemic lupus erythematosus and rheumatoid arthritis. We report that chloroquine promoted the transrepression of proinflammatory cytokines by the glucocorticoid receptor (GR). In a mouse collagen-induced arthritis model, chloroquine enhanced the therapeutic effects of glucocorticoid treatment. By inhibiting lysosome function, chloroquine synergistically activated glucocorticoid signaling. Lysosomal inhibition by either bafilomycin A1 (an inhibitor of the vacuolar adenosine triphosphatase) or knockdown of transcription factor EB (TFEB, a master activator of lysosomal biogenesis) mimicked the effects of chloroquine. The abundance of the GR, as well as that of the androgen receptor and estrogen receptor, correlated with changes in lysosomal biogenesis. Thus, we showed that glucocorticoid signaling is regulated by lysosomes, which provides a mechanistic basis for treating inflammation and autoimmune diseases with a combination of glucocorticoids and lysosomal inhibitors.
Msb1 is not essential for growth in the budding yeast Saccharomyces cerevisiae since msb1Δ cells do not display obvious phenotypes. Genetic studies suggest that Msb1 positively regulates Cdc42 function during bud development, since high-copy MSB1 suppressed the growth defect of temperature-sensitive cdc24 and cdc42 mutants at restrictive temperature, while deletion of MSB1 showed synthetic lethality with cdc24, bem1, and bem2 mutations. However, the mechanism of how Msb1 regulates Cdc42 function remains poorly understood. Here, we show that Msb1 localizes to sites of polarized growth during bud development and interacts with Cdc42 in the cells. In addition, Msb1 interacts with Boi1 and Boi2, two scaffold proteins that also interact with Cdc42 and Bem1. These findings suggest that Msb1 may positively regulate Cdc42 function by interacting with Cdc42, Boi1, and Boi2, which may promote the efficient assembly of Cdc42, Cdc24, and other proteins into a functional complex. We also show that Msb1 interacts with Rho1 in the cells and Msb1 overproduction inhibits the growth of rho1-104 and rho1-3 but not rho1-2 cells. The growth inhibition appears to result from the down-regulation of Rho1 function in glucan synthesis, specifically during early stage of bud development. These results suggest that Msb1 may coordinate Cdc42 and Rho1 functions during early stage of bud development by promoting Cdc42 function and inhibiting Rho1 function. Msb1 overproduction also affects cell morphology, septin organization, and causes increased, aberrant deposition of 1,3-β-glucan and chitin at the mother-bud neck. However, the stimulation of glucan synthesis mainly occurs during late, but not early, stage of bud development.
The aim of this study was to assess the association between non-high-density-lipoprotein-cholesterol (non-HDL-C) and the prevalence of asymptomatic intracranial arterial stenosis (ICAS).
Methods and Results
The Asymptomatic Polyvascular Abnormalities Community (APAC) study is a prospective cohort study based on the Kailuan district (China) population. A total of 5351 eligible subjects, aged ≥40, and without history of stroke or myocardial infarction, were enrolled in this study. Transcranial Doppler Ultrasonography (TCD) was performed on all enrolled subjects for the evaluation of ICAS presence. Out of 5351 patients, 698 subjects showed evidence of ICAS (prevalence of 13.04%). Multivariate analysis showed that non-HDL-C is an independent indicator for the presence of ICAS (OR = 1.15, 95%CI: 1.08 – 1.23), but with a gender difference (P for interaction<0.01): in men, non-HDL-C is an independent indicator for ICAS (multivariate-adjusted OR = 1.28, 95%CI: 1.18–1.39), but not in women (multivariate-adjusted OR = 1.03, 95%CI: 0.93–1.14). Subjects were divided into five subgroups based non-HDL-C levels and these levels correlated linearly with the prevalence of ICAS (P for trend <0.01). Compared with the first quintile, multivariate-adjusted OR (95%CI) of the second, third, fourth and fifth quintiles were: 1.05 (0.71–1.56), 1.33 (0.91–1.95), 1.83 (1.27–2.63), 2.48 (1.72–3.57), respectively.
Non-HDL-C is an independent predictor of ICAS prevalence in men but not in women, suggesting that non-HDL-C levels could be used as a surveillance factor in the primary prevention of ischemic stroke, especially in men.