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Items 3031 to 3035 of 3035 total

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  • Promotion of mitochondrial biogenesis via the regulation of PARIS and PGC-1α by parkin as a mechanism of neuroprotection by carnosic acid

    Lin, CY; Huang, YN; Fu, RH; Liao, YH; Kuo, TY; Tsai, CW
    Department of Nutrition, China Medical University, Taichung, Taiwan
    Product(s): Carnosic Acid
    Impairment of mitochondrial biogenesis is associated with the pathological progression of Parkinson's disease (PD). Parkin-interacting substrate (PARIS) can be ubiquitinated by parkin and prevents the repression of proliferator-activated receptor gamma coactivator-1-alpha (PGC-1α). This study investigated whether the neuroprotective mechanism of carnosic acid (CA) from rosemary is mediated via the regulation of PARIS and PGC-1α by parkin. The Western blotting and RT-PCR were used to determine protein and mRNA, respectively. To investigate the protein-protein interaction of between PARIS and ubiquitin, the immunoprecipitation assay (IP assay) was utilized. Silencing of endogenous parkin or PGC-1α was performed by using transient transfection of small interfering RNA (siRNA). SH-SY5Y cells treated with 6-hydroxydopamine (6-OHDA) increased PARIS protein, decreased PGC-1α protein, and reduced protein and mRNA of mitochondrial biogenesis-related genes. CA pretreatment reversed the effects of 6-OHDA. By IP assay, the interaction of PARIS with ubiquitin protein caused by CA was stronger than that caused by 6-OHDA. Moreover, knockdown of parkin attenuated the ability of CA to reverse the 6-OHDA-induced increase in PARIS and decrease in PGC-1α expression. PGC-1α siRNA was used to investigate how CA influenced the effect of 6-OHDA on the modulation of mitochondrial biogenesis and apoptosis. In the presence of PGC-1α siRNA, CA could no longer significantly reverse the reduction of mitochondrial biogenesis or the induction of cleavage of apoptotic-related proteins by 6-OHDA. The cytoprotective of CA is related to the enhancement of mitochondrial biogenesis by inhibiting PARIS and inducing PGC-1α by parkin. The activation of PGC-1α-mediated mitochondrial biogenesis by CA prevents the degeneration of dopaminergic neurons, CA may have therapeutic application in PD.
  • Arsenic compounds activate the MAPK and caspase pathways to induce apoptosis in OEC‑M1 gingival epidermal carcinoma

    Foo, NP; Ko, CL; Chu, CY; Wang, CY; So, EC; Huang, BM
    Department of Emergency Medicine, An Nan Hospital, China Medical University, Tainan 70965, Taiwan, R.O.C
    Product(s): Trypsin
    Arsenic is a well‑documented environmental toxicant that can induce neurotoxicity and peripheral vascular diseases. In fact, arsenic trioxide has been used to treat various cancer types. Oral cancer has been in the top ten common cancers for decades in Taiwan, and the incidence rate is continuously increasing. The majority of oral cancers are associated with excessive tobacco, alcohol consumption and betel chewing. To the best of our knowledge, no study has revealed the effect of arsenic compounds on oral cancers. Thus, the present study used OEC‑M1 oral squamous carcinoma cells treated with sodium arsenite (NaAsO2) and dimethylarsenic acid (DMA) to determine whether both arsenic compounds could exert anticancer effects on oral cancer. The results demonstrated that NaAsO2 and DMA induced rounding up and membrane blebbing in OEC‑M1 cells, which are morphological characteristics of apoptosis. Annexin V/PI double staining analysis further confirmed that both arsenic compounds induced apoptosis of OEC‑M1 cells. In addition, NaAsO2 and DMA significantly decreased the survival rate and increased the percentage of OEC‑M1 cells in the subG1 and G2/M phases (P<0.05). Furthermore, both arsenic compounds significantly activated the cleavage of caspase‑8, ‑9, ‑3 and PARP, and the phosphorylation of JNK, ERK1/2 and p38 in OEC‑M1 cells (P<0.05). Collectively, the findings of the present study indicated that NaAsO2 and DMA stimulate extrinsic and intrinsic apoptotic pathways through the activation of the MAPK pathways to induce apoptosis of OEC‑M1 cells, suggesting that NaAsO2 and DMA may be used as novel anticancer drugs for oral cancers.
  • Altered expression of ADM and ADM2 by hypoxia regulates migration of trophoblast and HLA-G expression†

    Gu, C; Park, S; Seok, J; Jang, HY; Bang, YJ; Kim, GIJ
    Metabolic and Biomolecular Engineering National Research Laboratory, Systems Metabolic Engineering and Systems Healthcare (SMESH) Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Plus Program), Institute for the BioCentury, Korea Adva
    Product(s): YC-1
    Preeclampsia (PE) is a placental disorder caused by endothelial dysfunction via trophoblast inadequate invasion activity. Adrenomedullin (ADM) and ADM2 are multi-functional peptides that can support vascular activity and placental growth. However, correlation between ADMs and trophoblast functions is currently unclear. The objective of this study was to analyze changes in expression of ADMs in placenta and HTR-8/SVneo trophoblast cells under hypoxia and their effects on invasion activity of trophoblast cells and expression of HLA-G. In placental tissues of PE, expression levels of ADM and HLA-G were significantly increased (P < 0.05) while expression of ADM2 was decreased compared to that in normal term placenta. Under hypoxia, expression levels of ADM, ADM2, and HLA-G and invasion ability of trophoblast cells were increased in hypoxia-inducible factor-1 (HIF-1α)- dependent manner (P < 0.05). Treatment with ADMs agonists reduced HIF-1α activity whereas enhanced invasion ability under hypoxia. However, they were not changed after co-treatment of ADMs and HIF-1α inhibitor, YC-1, although expression levels of invasion-related genes MMP2, MMP9, and Rac1 were altered (P < 0.05). ADMs also increased HLA-G expression under normoxia while ADM2 or co-treatment of ADMs under hypoxia attenuated HLA-G expression (P < 0.05). Our findings demonstrate that altered expression of ADMs plays a critical role in placental physiology, especially in trophoblast invasion and immune-modulation under hypoxia.
  • A developmental checkpoint directs metabolic remodelling as a strategy against starvation in Drosophila

    Yamada, T; Hironaka, KI; Habara, O; Morishita, Y; Nishimura, T
    Laboratory for Growth Control Signaling, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
    Product(s): Muristerone A
    Steroid hormones are crucial regulators of life-stage transitions during development in animals. However, the molecular mechanisms by which developmental transition through these stages is coupled with optimal metabolic homeostasis remains poorly understood. Here, we demonstrate through mathematical modelling and experimental validation that ecdysteroid-induced metabolic remodelling from resource consumption to conservation can be a successful life-history strategy to maximize fitness in Drosophila larvae in a fluctuating environment. Specifically, the ecdysteroid-inducible protein ImpL2 protects against hydrolysis of circulating trehalose following pupal commitment in larvae. Stored glycogen and triglycerides in the fat body are also conserved, even under fasting conditions. Moreover, pupal commitment dictates reduced energy expenditure upon starvation to maintain available resources, thus negotiating trade-offs in resource allocation at the physiological and behavioural levels. The optimal stage-specific metabolic shift elucidated by our predictive and empirical approaches reveals that Drosophila has developed a highly controlled system for ensuring robust development that may be conserved among higher-order organisms in response to intrinsic and extrinsic cues.
  • Targeting the Kaposi’s Sarcoma-associated Herpesvirus Genome With the CRISPR-Cas9 Platform in Latently Infected Cells

    Haddad, C; Kalt, I; Shovman, Y; Xia, L; Schlesinger, Y; Sarid, R; Parnas, O;
    Bar-Ilan University
    Kaposi’s sarcoma-associated herpesvirus (KSHV) is a transforming gammaherpes. Like other herpesviruses, KSHV infection is for life long and there is no treatment that can cure of patients from the virus. In addition, there is urgent need to target viral genes to study their role during the infection cycle. The CRISPR-Cas9 technology offers a means to target viral genomes and thus may offer a novel strategy for viral cure as well for better understanding of the infection process. We evaluated the suitability of this platform for the targeting of KSHV. Methods: We have used BAC16 genome, which contains an expression cassette encoding hygromycin-resistance and a GFP marker gene. Three genes were targeted: gfp which serves as a marker for infection; orf45 encoding a lytic viral protein; and orf73, encoding LANA which is crucial for latent infection. The fraction of cells expressing GFP as well as viral DNA levels and LANA expression were monitored and viral genomes were sequenced. Results: We found that KSHV episomes can be targeted by CRISPR-Cas9. Interestingly, the quantity of KSHV DNA declined, even when target sites were not functionally important for latency. In addition, we show that antibiotic selection, used to maintain infection, interferes with the outcome of targeting.Conclusions: Our study provides insights to the use of this fundamental approach for the study and manipulation of KSHV. It provides guidelines for the targeting CRISPR-Cas9 to the viral genome and for outcomes interpretation.

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