piperidines and ursodoxicoltaurine

Microgravity exposure results in vascular remodeling and cardiovascular dysfunction. Here, the effects of mitochondrial oxidative stress on vascular smooth muscle cells (VSMCs) in rat cerebral arteries under microgravity simulated by hindlimb unweighting (HU) was studied. Endoplasmic reticulum (ER)-resident transmembrane sensor proteins and phenotypic markers of rat cerebral VSMCs were examined. In HU rats, CHOP expression was increased gradually, and the upregulation of the PERK-eIF2α-ATF4 pathway was the most pronounced in cerebral arteries. Furthermore, PERK/p-PERK signaling, CHOP, GRP78 and reactive oxygen species were augmented by PERK overexpression but attenuated by the mitochondria-targeting antioxidant MitoTEMPO. Meanwhile, p-PI3K, p-Akt and p-mTOR protein levels in VSMCs were increased in HU rat cerebral arteries. Compared with the control, HU rats exhibited lower α-SMA, calponin, SM-MHC and caldesmon protein levels but higher OPN and elastin levels in cerebral VSMCs. The cerebral VSMC phenotype transition from a contractile to synthetic phenotype in HU rats was augmented by PERK overexpression and 740Y-P but reversed by MitoTEMPO and the ER stress inhibitors tauroursodeoxycholic acid (TUDCA) and 4-phenylbutyric acid (4-PBA). In summary, mitochondrial oxidative stress and ER stress induced by simulated microgravity contribute to phenotype transition of cerebral VSMCs through the PERK-eIF2a-ATF4-CHOP pathway in a rat model.

Topics: Activating Transcription Factor 4; Animals; Antioxidants; Cerebral Arteries; eIF-2 Kinase; Endoplasmic Reticulum; Eukaryotic Initiation Factor-2; Gene Expression Regulation; Heat-Shock Proteins; Hindlimb Suspension; Male; Mitochondria; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Organophosphorus Compounds; Phenylbutyrates; Phosphatidylinositol 3-Kinases; Piperidines; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Signal Transduction; Taurochenodeoxycholic Acid; TOR Serine-Threonine Kinases; Transcription Factor CHOP

The current study mainly aims to evaluate the effects of ibrutinib on endoplasmic reticulum stress (ERS)-induced apoptosis in Reh cells, which may shed light on the treatment of acute lymphoblastic leukemia (ALL) among children. In line with previous studies, our data show that ibrutinib significantly suppressed Reh cell viability in a time- and dose-dependent manner. We further evaluated the role of ibrutinib on Reh cell colony formation and apoptosis. Ibrutinib inhibited clonogenic capacity and induced Reh cell apoptosis, suggesting an anti-tumor effects of ibrutinib in the progression of ALL. Further study showed that ibrutinib treatment increased ERS-related protein expression, including Bip, ATF4 and CHOP, suggesting the induction of ER-stress in Reh cells. More importantly, once ER-stress was suppressed by tauroursodeoxycholic acid (TUDCA), an ER-stress inhibitor, the upregulation of Bip, ATF4, CHOP, cleaved-caspase3 and cleaved-PARP after ibrutinib treatment was partially reversed, suggesting that induction of ALL cell apoptosis by ibrutinib was partially attributed to activation of ER stress. In summary, we showed novel data that ER-stress induced cell apoptosis plays a key role in the therapeutic effects of ibrutinib on ALL cell malignancies.

Topics: Activating Transcription Factor 4; Adenine; Apoptosis; Caspase 3; Cell Line, Tumor; Cell Survival; Endoplasmic Reticulum; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Heat-Shock Proteins; Humans; Piperidines; Poly (ADP-Ribose) Polymerase-1; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Protein Kinase Inhibitors; Pyrazoles; Pyrimidines; Taurochenodeoxycholic Acid; Transcription Factor CHOP

The rat liver organic anion transporting polypeptide (Oatp1) has been extensively characterized mainly in the Xenopus laevis expression system as a polyspecific carrier transporting organic anions (bile salts), neutral compounds, and even organic cations. In this study, we extended this characterization using a mammalian expression system and confirm the basolateral hepatic expression of Oatp1 with a new antibody. Besides sulfobromophthalein [Michaelis-Menten constant (Km) of approximately 3 microM], taurocholate (Km of approximately 32 microM), and estradiol- 17beta-glucuronide (Km of approximately 4 microM), substrates previously shown to be transported by Oatp1 in transfected HeLa cells, we determined the kinetic parameters for cholate (Km of approximately 54 microM), glycocholate (Km of approximately 54 microM), estrone-3-sulfate (Km of approximately 11 microM), CRC-220 (Km of approximately 57 microM), ouabain (Km of approximately 3,000 microM), and ochratoxin A (Km of approximately 29 microM) in stably transfected Chinese hamster ovary (CHO) cells. In addition, three new substrates, taurochenodeoxycholate (Km of approximately 7 microM), tauroursodeoxycholate (Km of approximately 13 microM), and dehydroepiandrosterone sulfate (Km of approximately 5 microM), were also investigated. The results establish the polyspecific nature of Oatp1 in a mammalian expression system and definitely identify conjugated dihydroxy bile salts and steroid conjugates as high-affinity endogenous substrates of Oatp1.

Topics: Animals; Anion Transport Proteins; Carrier Proteins; CHO Cells; Cholic Acid; Cricetinae; Dehydroepiandrosterone Sulfate; Dipeptides; Estradiol; Estrone; Glycocholic Acid; HeLa Cells; Humans; Kinetics; Liver; Ochratoxins; Ouabain; Piperidines; Rats; Recombinant Proteins; Substrate Specificity; Sulfobromophthalein; Taurochenodeoxycholic Acid; Taurocholic Acid; Transfection; Xenopus laevis