To explore the effect of retinoid X receptor (RXR) agonist bexarotene on atherosclerosis and the potential mechanism in streptozotocin (STZ) induced diabetic apolipoprotein E knockout (apoE(-/-)) mice.Eight C57BL/6 mice served as control, 46 apoE(-/-) mice were randomized into 4 groups: apoE(-/-) group (n = 10), STZ+apoE(-/-) group (n = 12), STZ+apoE(-/-)+Bex 10 (10 mg×kg⁻¹×d⁻¹)group (n = 12), STZ+ apoE(-/-)+Bex 30 (30 mg×kg⁻¹×d⁻¹) group (n = 12). Diabetic apoE(-/-) animal model was established by intraperitoneal injection of STZ. Blood glucose was determined by glucose oxidase method. Patch area in thoracic aorta was measured by HE staining. Western blotting was used to determine the RXR and gp91(phox) protein level in thoracic aorta. Reactive oxygen species (ROS) level in blood and thoracic aorta homogenates was detected by Fenton and Griess method.(1) Patch areas of thoracic aorta were larger in apoE(-/-) group than in C57BL/6 group [(38.40 ± 8.95)µm² vs. (0.10 ± 0.01) µm², P < 0.01], further increased in STZ+apoE(-/-) group [(94.06 ± 8.04)µm², P < 0.05 vs. apoE(-/-) group] and significantly reduced in STZ+apoE(-/-)+Bex 10 group [(78.72 ± 4.62)µm², P < 0.05 vs. STZ+apoE(-/-) group] and further educed in STZ+apoE(-/-)+Bex 30 group [(46.13 ± 7.56)µm², P < 0.05 vs. STZ+apoE(-/-)+Bex 10 group]. (2) Blood glucose level, TG, TC, LDL-C, thoracic aorta gp91(phox) protein level and ROS level in blood and thoracic aorta homogenates were significantly higher in STZ+apoE(-/-) group than in apoE(-/-) group (all P < 0.05). Blood glucose level and TG, TC, LDL-C levels were similar between STZ+apoE(-/-)+Bex10 and STZ+apoE(-/-) group. Thoracic aorta gp91(phox) protein level and ROS level in blood and thoracic aorta homogenates were lower in STZ+apoE(-/-)+Bex 10 group than in STZ+apoE(-/-) group (P < 0.05). Blood glucose level, TG, TC, LDL-C levels, gp91(phox) expression in thoracic aorta, ROS level in blood and thoracic in STZ+apoE(-/-)+Bex 30 group were lower than in STZ+apoE(-/-) group (all P < 0.05).Bexarotene treatment could attenuate arteriosclerosis progression in STZ induced diabetic apoE(-/-) mice, the underlying mechanism might be related to suppressing oxidative stress and decreasing blood glucose level and improving lipids metabolism.
Abstract Background Neuronal uptake and subsequent spread of proteopathic seeds, such as αS (alpha-synuclein), Tau, and TDP-43, contribute to neurodegeneration. The cellular machinery participating in this process is poorly understood. One proteinopathy called multisystem proteinopathy (MSP) is associated with dominant mutations in Valosin Containing Protein (VCP). MSP patients have muscle and neuronal degeneration characterized by aggregate pathology that can include αS, Tau and TDP-43. Methods We performed a fluorescent cell sorting based genome-wide CRISPR-Cas9 screen in αS biosensors. αS and TDP-43 seeding activity under varied conditions was assessed using FRET/Flow biosensor cells or immunofluorescence for phosphorylated αS or TDP-43 in primary cultured neurons. We analyzed in vivo seeding activity by immunostaining for phosphorylated αS following intrastriatal injection of αS seeds in control or VCP disease mutation carrying mice. Results One hundred fifty-four genes were identified as suppressors of αS seeding. One suppressor, VCP when chemically or genetically inhibited increased αS seeding in cells and neurons. This was not due to an increase in αS uptake or αS protein levels. MSP-VCP mutation expression increased αS seeding in cells and neurons. Intrastriatal injection of αS preformed fibrils (PFF) into VCP-MSP mutation carrying mice increased phospho αS expression as compared to control mice. Cells stably expressing fluorescently tagged TDP-43 C-terminal fragment FRET pairs (TDP-43 biosensors) generate FRET when seeded with TDP-43 PFF but not monomeric TDP-43. VCP inhibition or MSP-VCP mutant expression increases TDP-43 seeding in TDP-43 biosensors. Similarly, treatment of neurons with TDP-43 PFFs generates high molecular weight insoluble phosphorylated TDP-43 after 5 days. This TDP-43 seed dependent increase in phosphorlyated TDP-43 is further augmented in MSP-VCP mutant expressing neurons. Conclusion Using an unbiased screen, we identified the multifunctional AAA ATPase VCP as a suppressor of αS and TDP-43 aggregate seeding in cells and neurons. VCP facilitates the clearance of damaged lysosomes via lysophagy. We propose that VCP’s surveillance of permeabilized endosomes may protect against the proteopathic spread of pathogenic protein aggregates. The spread of distinct aggregate species may dictate the pleiotropic phenotypes and pathologies in VCP associated MSP.
SUMMARY Uptake and spread of proteopathic seeds, such as αS, Tau, and TDP-43, contribute to neurodegeneration. The cellular machinery necessary for this process is poorly understood. Using a genome-wide CRISPR-Cas9 screen, we identified Valosin Containing Protein (VCP) as a suppressor of αS seeding. Dominant mutations in VCP cause multisystem proteinopathy (MSP) with muscle and neuronal degeneration. VCP inhibition or disease mutations increase αS seeding in cells and neurons. This is not associated with an increase in seed uptake and is similar to treatment with the lysosomal damaging agent, LLoME. Intrastriatal injection of αS seeds into VCP disease mice enhances seeding efficiency compared with controls. This is not specific to αS since VCP inhibition or disease mutations increased TDP-43 seeding in neurons. These data support that VCP protects against proteopathic spread of pathogenic aggregates. The spread of distinct aggregate species may dictate pleiotropic phenotypes and pathologies in VCP associated MSP.
Cancer research over the past decades has focused on neoplastic cells, or a fraction of them, i.e. tumor stem cells, as the ultimate causes of tumorigenesis.However, during recent years, scientists have come to realize that tumorigenesis is not a solo act of neoplastic cells, but rather a cooperative process in which the roles of numerous types of non-neoplastic cells should be recognized.These tumor-residing non-neoplastic cells constitute the so-called tumor-associated stroma, which in certain cases even greatly surpasses the neoplastic cellular compartment that was previously thought of as a sole determiner leading to a seemingly autonomous growth pattern.In this review, we summarize several recent research highlights that have unveiled many previously unappreciated roles for microenvironmental factors, especially during the initiation stage of tumorigenesis.It is becoming increasingly clear that the stroma's regulatory effects constitute not only an essential force for maintaining tumor growth, but also primary causes initiating tumorigenesis.
The spontaneous hydrolysis reactions of 2-(4-nitrophenoxy)tetrahydropyran (6a) and 2-(4-cyanophenoxy)tetrahydropyran (6b) are accelerated in the presence of α-cyclodextrin (α-CD), but are slowed by the addition of β-CD, γ-CD, or mono[2-O-(carboxymethyl)]-β-CD (β-CD-acid 5). The observed rate constants for the hydrolysis reactions in the presence of CD are consistent with the CD-catalysed reaction occurring from a 1∶1 complex of cyclodextrin with the substrate. In contrast, hydrolysis does not occur from the 1∶1 complex for reactions conducted at high pH values at which ionisation of the CD becomes important. The spontaneous hydrolysis reactions for both anomers of 2-deoxyglucopyranosylpyridinium salts are markedly accelerated by the addition of β-CD. In these reactions, the binding affinity of the β-CD cavity for the heteroaromatic ring of the pyridinium substrate increases in response to a decreasing positive charge on the ring moiety that occurs with approach to the transition state, and this results in catalysis.
Histone deacetylase inhibitors (HDACi),such as trichostatin A (TSA),can significantly enhance the developmental competence of somatic cell nuclear transfer (SCNT) embryos.The present study was designed to examine the effect of TSA,especially the concentration of TSA and the treat period,on the development of pig SCNT embryos.The reaults showed that the treatment of cloned pig embryos with 40 nmol·L-1 TSA could significantly improve the in vitro blastocyst rate compared with the control group,whereas no significant deference of the blastocyst rate was observed between treatment period of 12 and 24 h.40 nmol·L-1 TSA treated 12 h could enhance the blstocyst rate of porcine SCNT embryos regardless of the difference of donor cells compared with control group,but there was no significant difference of the blastocyst rate between SCNT embryos reconstructed with diffirent donor cells.These results indicated that 40 nmol·L-1 TSA treated 12 or 24 h could enhance the porcine SCNT embryos in vitro development competence.
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