Showing papers by "Charlie Norwood VA Medical Center published in 2016"
TL;DR: It is suggested that persistent activation of autophagy in kidney proximal tubules promotes renal interstitial fibrosis during UUO.
Abstract: Renal fibrosis is the final, common pathway of end-stage renal disease. Whether and how autophagy contributes to renal fibrosis remains unclear. Here we first detected persistent autophagy in kidney proximal tubules in the renal fibrosis model of unilateral ureteral obstruction (UUO) in mice. UUO-associated fibrosis was suppressed by pharmacological inhibitors of autophagy and also by kidney proximal tubule-specific knockout of autophagy-related 7 (PT-Atg7 KO). Consistently, proliferation and activation of fibroblasts, as indicated by the expression of ACTA2/α-smooth muscle actin and VIM (vimentin), was inhibited in PT-Atg7 KO mice, so was the accumulation of extracellular matrix components including FN1 (fibronectin 1) and collagen fibrils. Tubular atrophy, apoptosis, nephron loss, and interstitial macrophage infiltration were all inhibited in these mice. Moreover, these mice showed a specific suppression of the expression of a profibrotic factor FGF2 (fibroblast growth factor 2). In vitro, TGFB1 (transforming growth factor β 1) induced autophagy, apoptosis, and FN1 accumulation in primary proximal tubular cells. Inhibition of autophagy suppressed FN1 accumulation and apoptosis, while enhancement of autophagy increased TGFB1-induced-cell death. These results suggest that persistent activation of autophagy in kidney proximal tubules promotes renal interstitial fibrosis during UUO. The profibrotic function of autophagy is related to the regulation on tubular cell death, interstitial inflammation, and the production of profibrotic factors.
171 citations
TL;DR: The data determine that PD-L1 is highly expressed in tumor-infiltrating MDSCs and in a lesser degree in lymphoid organs, and the pSTAT1-IRF1 axis regulates PD- L1 expression in M DSCs.
Abstract: Programmed death-ligand 1 (PD-L1) is an inhibitory ligand that binds to PD-1 to suppress T cell activation. PD-L1 is constitutively expressed and inducible in tumor cells, but the expression profiles and regulatory mechanism of PD-L1 in myeloid-derived suppressor cells (MDSCs) are largely unknown. We report that PD-L1 is abundantly expressed in tumor-infiltrating leukocytes in human patients with both microsatellite instable and microsatellite stable colon cancer. About 60% CD11b+CD33+HLA-DR- MDSCs from peripheral blood of human colon cancer patients are PD-L1+. PD-L1+ MDSCs are also significantly higher in tumor-bearing mice than in tumor-free mice. Interestingly, the highest PD-L1+ MDSCs were observed in the tumor microenvironment in which 56-71% tumor-infiltrating MDSCs are PD-L1+in vivo. In contrast, PD-L1+ MDSCs are significantly less in secondary lymphoid organs and peripheral blood as compared to the tumor tissues, whereas bone marrow MDSCs are essentially PD-L1- in tumor-bearing mice. IFNγ is highly expressed in cells of the tumor tissues and IFNγ neutralization significantly decreased PD-L1+ MDSCs in the tumor microenvironment in vivo. However, IFNγ-activated pSTAT1 does not bind to the cd274 promoter in MDSCs. Instead, pSTAT1 activates expression of IRF1, IRF5, IRF7 and IRF8 in MDSCs, and only pSTAT1-activated IRF1 binds to a unique IRF-binding sequence element in vitro and chromatin in vivo in the cd274 promoter to activate PD-L1 transcription. Our data determine that PD-L1 is highly expressed in tumor-infiltrating MDSCs and in a lesser degree in lymphoid organs, and the pSTAT1-IRF1 axis regulates PD-L1 expression in MDSCs.
156 citations
TL;DR: The basics of EVs are introduced, the present information about the involvement, diagnostic value, and therapeutic potential of EVs in major kidney diseases are analyzed, and the mechanism underlying EV production and secretion remains elusive.
Abstract: Extracellular vesicles (EV) are endogenously produced, membrane-bound vesicles that contain various molecules. Depending on their size and origins, EVs are classified into apoptotic bodies, microvesicles, and exosomes. A fundamental function of EVs is to mediate intercellular communication. In kidneys, recent research has begun to suggest a role of EVs, especially exosomes, in cell-cell communication by transferring proteins, mRNAs, and microRNAs to recipient cells as nanovectors. EVs may mediate the cross talk between various cell types within kidneys for the maintenance of tissue homeostasis. They may also mediate the cross talk between kidneys and other organs under physiological and pathological conditions. EVs have been implicated in the pathogenesis of both acute kidney injury and chronic kidney diseases, including renal fibrosis, end-stage renal disease, glomerular diseases, and diabetic nephropathy. The release of EVs with specific molecular contents into urine and plasma may be useful biomarkers for kidney disease. In addition, EVs produced by cultured cells may have therapeutic effects for these diseases. However, the role of EVs in kidney diseases is largely unclear, and the mechanism underlying EV production and secretion remains elusive. In this review, we introduce the basics of EVs and then analyze the present information about the involvement, diagnostic value, and therapeutic potential of EVs in major kidney diseases.
132 citations
TL;DR: It is suggested that breast CSCs are intrinsically sensitive to genetic and epigenetic modifications and can therefore be significantly affected by epigenetic-based therapies, warranting further investigation of combined DNMT and HDAC inhibition in refractory or drug-resistant breast cancer.
Abstract: Recently, impressive technical advancements have been made in the isolation and validation of mammary stem cells and cancer stem cells (CSC), but the signaling pathways that regulate stem cell self-renewal are largely unknown. Furthermore, CSCs are believed to contribute to chemo- and radioresistance. In this study, we used the MMTV-Neu-Tg mouse mammary tumor model to identify potential new strategies for eliminating CSCs. We found that both luminal progenitor and basal stem cells are susceptible to genetic and epigenetic modifications, which facilitate oncogenic transformation and tumorigenic potential. A combination of the DNMT inhibitor 5-azacytidine and the HDAC inhibitor butyrate markedly reduced CSC abundance and increased the overall survival in this mouse model. RNA-seq analysis of CSCs treated with 5-azacytidine plus butyrate provided evidence that inhibition of chromatin modifiers blocks growth-promoting signaling molecules such as RAD51AP1 and SPC25, which play key roles in DNA damage repair and kinetochore assembly. Moreover, RAD51AP1 and SPC25 were significantly overexpressed in human breast tumor tissues and were associated with reduced overall patient survival. In conclusion, our studies suggest that breast CSCs are intrinsically sensitive to genetic and epigenetic modifications and can therefore be significantly affected by epigenetic-based therapies, warranting further investigation of combined DNMT and HDAC inhibition in refractory or drug-resistant breast cancer. Cancer Res; 76(11); 3224-35. ©2016 AACR.
117 citations
TL;DR: The novel role of SFKs, particularly c-Src in mediating EMT, modulation of tumor endothelial-barrier, transendothelial migration (microinvasion) and metastasis of cancer cells, and the utility of Src inhibitors in vascular normalization and cancer therapy are reviewed.
112 citations
TL;DR: This review proposes experimental strategies for the identification of renoprotective agents or methods with clinical potential in acute kidney injury and proposes the consideration of combination therapy by targeting multiple targets in AKI.
88 citations
TL;DR: In the developing mouse neocortex, the YAP transcription factor is activated by BMP2 signaling, and in turn stabilises Smad1 to promote proliferation and differentiation of astrocytes.
Abstract: YAP (yes-associated protein), a key transcriptional co-factor that is negatively regulated by the Hippo pathway, is crucial for the development and size control of multiple organs, including the liver. However, its role in the brain remains unclear. Here, we provide evidence for YAP regulation of mouse neocortical astrocytic differentiation and proliferation. YAP was undetectable in neurons, but selectively expressed in neural stem cells (NSCs) and astrocytes. YAP in NSCs was required for neocortical astrocytic differentiation, with no apparent role in self-renewal or neural differentiation. However, YAP in astrocytes was necessary for astrocytic proliferation. Yap (Yap1) knockout, Yap(nestin) conditional knockout and Yap(GFAP) conditional knockout mice displayed fewer neocortical astrocytes and impaired astrocytic proliferation and, consequently, death of neocortical neurons. Mechanistically, YAP was activated by BMP2, and the active/nuclear YAP was crucial for BMP2 induction and stabilization of SMAD1 and astrocytic differentiation. Expression of SMAD1 in YAP-deficient NSCs partially rescued the astrocytic differentiation deficit in response to BMP2. Taken together, these results identify a novel function of YAP in neocortical astrocytic differentiation and proliferation, and reveal a BMP2-YAP-SMAD1 pathway underlying astrocytic differentiation in the developing mouse neocortex.
88 citations
TL;DR: Reactive astrogliosis was associated with blood–brain barrier dysfunction in YAP brain-selective knockout mice and a pathway of YAP-SOCS for the negatively control of neuro inflammation was revealed.
Abstract: Yes-associated protein (YAP) is a key transcriptional cofactor of the Hippo pathway, critical for the development of multiple organs. However, its role in the developing brain remains poorly understood. Here, we found that YAP was highly expressed in astrocytes and YAP deletion elevated the astrocytic activation in culture and in vivo, which was associated with microglial activation. At the molecular level, YAP in astrocytes was activated by IFNβ or ciliary neurotrophic factor (CNTF), which was necessary for IFNβ or CNTF induction of the suppressor of cytokine signaling 3 (SOCS3), a negative regulator of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) inflammatory pathway. YAP(-/-) astrocytes thus showed hyperactivation of the JAK-STAT inflammatory pathway and reactive astrogliosis. Expression of SOCS3 in YAP(-/-) astrocytes prevented the hyperactivation of STAT3 and partially restored the astrocytic activation. Finally, reactive astrogliosis was associated with blood-brain barrier dysfunction in YAP brain-selective knockout mice. Taken together, these results identify unrecognized functions of YAP in preventing reactive astrogliosis and reveal a pathway of YAP-SOCS for the negatively control of neuroinflammation.
79 citations
TL;DR: It is shown that autophagy was induced in kidney tubular cells in mice by the endotoxin lipopolysaccharide (LPS) and this work demonstrates convincing evidence ofAutophagy activation in endotoxic kidney injury and support a renoprotective role of Autophagy in kidney Tubules.
Abstract: Endotoxemia in sepsis, characterized by systemic inflammation, is a major cause of acute kidney injury (AKI) in hospitalized patients, especially in intensive care unit; however the underlying pathogenesis is poorly understood. Autophagy is a conserved, cellular catabolic pathway that plays crucial roles in cellular homeostasis including the maintenance of cellular function and viability. The regulation and role of autophagy in septic or endotoxic AKI remains unclear. Here we show that autophagy was induced in kidney tubular cells in mice by the endotoxin lipopolysaccharide (LPS). Pharmacological inhibition of autophagy with chloroquine enhanced LPS-induced AKI. Moreover, specific ablation of autophagy gene 7 (Atg7) from kidney proximal tubules worsened LPS-induced AKI. Together, the results demonstrate convincing evidence of autophagy activation in endotoxic kidney injury and support a renoprotective role of autophagy in kidney tubules.
79 citations
TL;DR: It is imperative to review this topic because recent discoveries have improved mechanistic understanding of the autophagic process and have highlighted its broad clinical applications, making autophagy a major target for drug development.
78 citations
TL;DR: Observations indicate that a ceramidase inhibitor is potentially an effective adjunct therapeutic agent for suppression of MDSCs to enhance the efficacy of CTL-based cancer immunotherapy.
Abstract: // Feiyan Liu 1 , Xia Li 1 , Chunwan Lu 2,3 , Aiping Bai 4 , Jacek Bielawski 4 , Alicja Bielawska 4 , Brendan Marshall 5 , Patricia V. Schoenlein 5 , Iryna O. Lebedyeva 6 and Kebin Liu 2,3,7 1 College of Life Sciences, Zhejiang University, Hangzhou, China 2 Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, GA, USA 3 Charlie Norwood VA Medical Center, Augusta, GA, USA 4 Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA 5 Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta, GA, USA 6 Department of Chemistry and Physics, Augusta University, Augusta, GA, USA 7 Georgia Cancer Center, Augusta University, Augusta, GA, USA Correspondence to: Feiyan Liu, email: // Keywords : MDSCs, cathepsin, ceramide, autophagy flux, Lysosomal cell death, Immunology and Microbiology Section, Immune response, Immunity Received : October 10, 2016 Accepted : November 07, 2016 Published : November 17, 2016 Abstract Myeloid-derived suppressor cells (MDSCs) are immune suppressive cells that are hallmarks of human cancer. MDSCs inhibit cytotoxic T lymphocytes (CTLs) and NK cell functions to promote tumor immune escape and progression, and therefore are considered key targets in cancer immunotherapy. Recent studies determined a key role of the apoptosis pathways in tumor-induced MDSC homeostasis and it is known that ceramide plays a key role in regulation of mammalian cell apoptosis. In this study, we aimed to determine the efficacy and underlying molecular mechanism of ceramide in suppression of MDSCs. Treatment of tumor-bearing mice with LCL521, a lysosomotropic inhibitor of acid ceramidase, significantly decreased MDSC accumulation in vivo . Using a MDSC-like myeloid cell model, we determined that LCL521 targets lysosomes and increases total cellular C16 ceramide level. Although MDSC-like cells have functional apoptosis pathways, LCL521-induced MDSC death occurs in an apoptosis- and necroptosis-independent mechanism. LCL521 treatment resulted in an increase in the number of autophagic vesicles, heterolysosomes and swollen ERs. Finally, concomitant inhibition of cathepsin B and cathepsin D was required to significantly decrease LCL521-induced cell death. Our observations indicate that LCL521 targets lysosomes to activate cathepsin B and cathepsin D, resulting in interrupted autophagy and ER stress that culminates in MDSC death. Therefore, a ceramidase inhibitor is potentially an effective adjunct therapeutic agent for suppression of MDSCs to enhance the efficacy of CTL-based cancer immunotherapy.
TL;DR: Targeting DDR for kidney protection in AKI relies on a thorough elucidation of the DDR pathways in various forms of AKI.
TL;DR: This mouse model is simple and yet sensitive in quantifying breast cancer cell growth in the primary site and progression kinetics to distant organs, and thus is an excellent model for studying breast cancer growth and progression, and for testing anti-metastasis therapeutic and immunotherapeutic agents in vivo.
Abstract: Metastasis is the primary cause of mortality of breast cancer patients. The mechanism underlying cancer cell metastasis, including breast cancer metastasis, is largely unknown and is a focus in cancer research. Various breast cancer spontaneous metastasis mouse models have been established. Here, we report a simplified procedure to establish orthotopic transplanted breast cancer primary tumor and resultant spontaneous metastasis that mimic human breast cancer metastasis. Combined with the bioluminescence live tumor imaging, this mouse model allows tumor growth and progression kinetics to be monitored and quantified. In this model, a low dose (1 x 104 cells) of 4T1-Luc breast cancer cells was injected into BALB/c mouse mammary fat pad using a tuberculin syringe. Mice were injected with luciferin and imaged at various time points using a bioluminescent imaging system. When the primary tumors grew to the size limit as in the IACUC-approved protocol (approximately 30 days), mice were anesthetized under constant flow of 2% isoflurane and oxygen. The tumor area was sterilized with 70% ethanol. The mouse skin around the tumor was excised to expose the tumor which was removed with a pair of sterile scissors. Removal of the primary tumor extends the survival of the 4T-1 tumor-bearing mice for one month. The mice were then repeatedly imaged for metastatic tumor spreading to distant organs. Therapeutic agents can be administered to suppress tumor metastasis at this point. This model is simple and yet sensitive in quantifying breast cancer cell growth in the primary site and progression kinetics to distant organs, and thus is an excellent model for studying breast cancer growth and progression, and for testing anti-metastasis therapeutic and immunotherapeutic agents in vivo.
TL;DR: A previously unappreciated enzymatic function of rapsyn and a role of neddylation in synapse formation are identified, and a potential target of therapeutic intervention for relevant neurological disorders is revealed.
TL;DR: Deletion of A2 was found to be beneficial in reducing neurovascular degeneration after I/R, and ERG showed improved positive scotopic threshold response with A2 deletion.
Abstract: Retinal ischemia is a major cause of visual impairment and blindness and is involved in various disorders including diabetic retinopathy, glaucoma, optic neuropathies and retinopathy of prematurity. Neurovascular degeneration is a common feature of these pathologies. Our lab has previously reported that the ureahydrolase arginase 2 (A2) is involved in ischemic retinopathies. Here, we are introducing A2 as a therapeutic target to prevent neurovascular injury after retinal ischemia/reperfusion (I/R) insult. Studies were performed with mice lacking both copies of A2 (A2-/-) and wild-type (WT) controls (C57BL6J). I/R insult was conducted on the right eye and the left eye was used as control. Retinas were collected for analysis at different times (3 h-4 week after injury). Neuronal and microvascular degeneration were evaluated using NeuN staining and vascular digests, respectively. Glial activation was evaluated by glial fibrillary acidic protein expression. Necrotic cell death was studied by propidium iodide labeling and western blot for RIP-3. Arginase expression was determined by western blot and quantitative RT-PCR. Retinal function was determined by electroretinography (ERG). A2 mRNA and protein levels were increased in WT I/R. A2 deletion significantly reduced ganglion cell loss and microvascular degeneration and preserved retinal morphology after I/R. Glial activation, reactive oxygen species formation and cell death by necroptosis were significantly reduced by A2 deletion. ERG showed improved positive scotopic threshold response with A2 deletion. This study shows for the first time that neurovascular injury after retinal I/R is mediated through increased expression of A2. Deletion of A2 was found to be beneficial in reducing neurovascular degeneration after I/R.
TL;DR: Hyperglycemia significantly increased MMP3 activity in the brain after stroke, and this was associated with exacerbated HT and worsened functional outcomes, pointing out M MP3 as a potential therapeutic target in hyperglycemic stroke.
Abstract: Background and Purpose— Acute hyperglycemia worsens the clinical outcomes and exacerbates cerebral hemorrhage after stroke. The mediators of hemorrhagic transformation (HT) in hyperglycemic stroke are not fully understood. Matrix metalloproteinase 3 (MMP3) plays a critical role in the tissue-type plasminogen activator–induced HT. However, the role of MMP3 in exacerbating the HT and worsening the functional outcomes in hyperglycemic stroke remains unknown.
Methods— Control/normoglycemic and hyperglycemic (blood glucose, 140–200 mg/dL) male Wistar rats were subjected to middle cerebral artery occlusion for 90 minutes and either 24 hours or 7 days reperfusion. MMP3 was inhibited pharmacologically (UK 356618, 15 mg/kg IV at reperfusion) or knocked down in the brain by shRNA lentiviral particles (injected intracerebroventricular). Neurovascular injury was assessed at 24 hours, and functional outcomes were assessed at 24 hours, day 3, and day 7. MMP3 activity was measured in brain homogenate and cerebral macrovessels. Localization of MMP3 within the neurovascular unit after hyperglycemic stroke was demonstrated by immunohistochemistry.
Results— Hyperglycemia significantly increased MMP3 activity in the brain after stroke, and this was associated with exacerbated HT and worsened functional outcomes. MMP3 inhibition significantly reduced HT and improved functional outcomes.
Conclusions— MMP3 plays a critical role in mediating cerebrovascular injury in hyperglycemic stroke. Our findings point out MMP3 as a potential therapeutic target in hyperglycemic stroke.
02 Jun 2016
TL;DR: In this paper, the authors detected persistent autophagy in kidney proximal tubules in the renal fibrosis model of unilateral ureteral obstruction (UUO) in mice.
Abstract: Renal fibrosis is the final, common pathway of end-stage renal disease. Whether and how autophagy contributes to renal fibrosis remains unclear. Here we first detected persistent autophagy in kidney proximal tubules in the renal fibrosis model of unilateral ureteral obstruction (UUO) in mice. UUO-associated fibrosis was suppressed by pharmacological inhibitors of autophagy and also by kidney proximal tubule-specific knockout of autophagy-related 7 (PT-Atg7 KO). Consistently, proliferation and activation of fibroblasts, as indicated by the expression of ACTA2/α-smooth muscle actin and VIM (vimentin), was inhibited in PT-Atg7 KO mice, so was the accumulation of extracellular matrix components including FN1 (fibronectin 1) and collagen fibrils. Tubular atrophy, apoptosis, nephron loss, and interstitial macrophage infiltration were all inhibited in these mice. Moreover, these mice showed a specific suppression of the expression of a profibrotic factor FGF2 (fibroblast growth factor 2). In vitro, TGFB1 (transforming growth factor β 1) induced autophagy, apoptosis, and FN1 accumulation in primary proximal tubular cells. Inhibition of autophagy suppressed FN1 accumulation and apoptosis, while enhancement of autophagy increased TGFB1-induced-cell death. These results suggest that persistent activation of autophagy in kidney proximal tubules promotes renal interstitial fibrosis during UUO. The profibrotic function of autophagy is related to the regulation on tubular cell death, interstitial inflammation, and the production of profibrotic factors.
TL;DR: Clinical and genetic evidence is provided that p53 was associated with the development of VAN induced AKI through upregulation of miR-192-5p through in vivo inhibition and suppression of p53-KO mice.
Abstract: Pathogenic role of p53 in AKI remains controversial and the underlying mechanism is unclear. Here, we tested whether the inhibition of p53 may ameliorate vancomycin (VAN) induced acute kidney injury (AKI). Mice with p53 knock out (p53-KO) were resistant to VAN induced AKI, indicated by the analysis of renal function, histology, and apoptosis. Mechanistically, AKI was associated with the upregulation of several known p53 target genes, including Bax and p21, and this association was attenuated in p53-KO mice. Furthermore, the expression of miR-192-5p was significantly decreased in the p53-KO kidney tissues. In human renal tubular epithelial cell line (HK-2), VAN induced p53 accumulation and miR-192-5p expression. Both apoptosis of HK-2 cells and expression of miR-192-5p were also suppressed by pifithrin-α. Anti-miR-192-5p significantly blocked VAN-induced apoptosis and caspase activity in HK-2 cells. Consistently, in vivo inhibition of miR-192-5p also suppressed VAN induced AKI. Thus, we provided clinical and genetic evidence that p53 was associated with the development of VAN induced AKI through upregulation of miR-192-5p.
TL;DR: Novel insights are provided on the endothelial-barrier protective role of VEGF in the long term and the importance of Akt1-FoxO signaling on tight-junction stabilization and prevention of vascular leakage through claudin expression.
Abstract: Vascular permeability regulated by the vascular endothelial growth factor (VEGF) through endothelial-barrier junctions is essential for inflammation. Mechanisms regulating vascular permeability remain elusive. Although 'Akt' and 'Src' have been implicated in the endothelial-barrier regulation, it is puzzling how both agents that protect and disrupt the endothelial-barrier activate these kinases to reciprocally regulate vascular permeability. To delineate the role of Akt1 in endothelial-barrier regulation, we created endothelial-specific, tamoxifen-inducible Akt1 knockout mice and stable ShRNA-mediated Akt1 knockdown in human microvascular endothelial cells. Akt1 loss leads to decreased basal and angiopoietin1-induced endothelial-barrier resistance, and enhanced VEGF-induced endothelial-barrier breakdown. Endothelial Akt1 deficiency resulted in enhanced VEGF-induced vascular leakage in mice ears, which was rescued upon re-expression with Adeno-myrAkt1. Furthermore, co-treatment with angiopoietin1 reversed VEGF-induced vascular leakage in an Akt1-dependent manner. Mechanistically, our study revealed that while VEGF-induced short-term vascular permeability is independent of Akt1, its recovery is reliant on Akt1 and FoxO-mediated claudin expression. Pharmacological inhibition of FoxO transcription factors rescued the defective endothelial barrier due to Akt1 deficiency. Here we provide novel insights on the endothelial-barrier protective role of VEGF in the long term and the importance of Akt1-FoxO signaling on tight-junction stabilization and prevention of vascular leakage through claudin expression.
TL;DR: Mitochondrial damage or dysfunction contribute critically to the pathogenesis of various diseases, including AKI, and upon stress, mitochondrial dynamics are disrupted and membrane integrity is compromised, resulting in the release of apoptogenic factors, mitochondrial permeability transition (MPT).
Abstract: Mitochondrial damage or dysfunction contribute critically to the pathogenesis of various diseases, including AKI. Upon stress, mitochondrial dynamics are disrupted and membrane integrity is compromised, resulting in the release of apoptogenic factors, mitochondrial permeability transition (MPT),
TL;DR: Owning a cat rather than a dog was significantly associated with a reduced hazard of dying from CVD events, in particular, stroke.
Abstract: In a recent statement, the American Heart Association stated “There are scant data on pet ownership and survival in people without established cardiovascular disease (CVD)”. This study sought to fill this gap. We analyzed nationally representative data of 3964 adults aged ≥50 who were free from major physical illnesses. Pet ownership was assessed at baseline between 1988 and 1994. Vital status was followed through December 31st 2006. With dogs being most popular pets owned by 22.0 (standard error 0.34) % of the participants, 34.6 % of the study population owned a pet. Pet ownership was associated with low rates of CVD deaths [hazard ratio (HR) = 0.69 (95 % CI 0.45–1.07)] and stroke [0.54 (0.28–1.01)] at borderline significant levels among women. These associations were adjusted for physical activity and largely attributed to having a cat rather than a dog. Among cat owners, the HR of all CVD deaths was 0.62 (0.36–1.05) and the HR of dying from stroke was 0.22 (0.07–0.68) compared with non-cat owners. The corresponding HRs among dog owners were 0.82 (0.51–1.34) and 0.76 (0.34–1.71) respectively. No similar associations were observed among men. The hazard of dying from hypertension was not associated with pet ownership for both men and women. Owning a cat rather than a dog was significantly associated with a reduced hazard of dying from CVD events, in particular, stroke. The protection pets confer may not be from physical activities, but possibly due to personality of the pet owners or stress-relieving effects of animal companionship.
TL;DR: Evidence supporting the concept that nuclear GM1 is associated with gene regulation in neuronal cells is presented, and it is demonstrated for the first time that GM1 interacts with chromatin via acetylated histones at the nuclear periphery of neuronal cells.
Abstract: Gangliosides are sialic acid-containing glycosphingolipids that are most abundant in the nerve tissues. The quantity and expression pattern of gangliosides in brain change drastically throughout development and are mainly regulated through stage-specific expression of glycosyltransferase (ganglioside synthase) genes. We previously demonstrated that acetylation of histones H3 and H4 on the N-acetylgalactosaminyltransferase I (GalNAcT, GA2/GM2/GD2/GT2-synthase) gene promoter resulted in recruitment of trans-activation factors. In addition, we reported that epigenetic activation of the GalNAcT gene was also detected as accompanied by an apparent induction of neuronal differentiation in neural stem cells responding to an exogenous supplement of ganglioside GM1. Here, we present evidence supporting the concept that nuclear GM1 is associated with gene regulation in neuronal cells. We found that nuclear GM1 binds acetylated histones on the promoters of the GalNAcT and NeuroD1 genes in differentiated neurons. Our study demonstrates for the first time that GM1 interacts with chromatin via acetylated histones at the nuclear periphery of neuronal cells.
TL;DR: It is reported here that 5-FU treatment selectively enriches a subset of CD133+ colon cancer cells in vitro, and it is determined thatCD133+CD24lo phenotype defines 5-fu-resistant human colon cancer stem cell-like cells.
Abstract: // Amy V. Paschall 1, 2, 3 , Dafeng Yang 1, 3 , Chunwan Lu 1, 3 , Priscilla S. Redd 1, 2, 3 , Jeong-Hyeon Choi 2 , Christopher M. Heaton 3 , Jeffrey R. Lee 3 , Asha Nayak-Kapoor 2, 3 , Kebin Liu 1, 2, 3 1 Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA 2 Georgia Cancer Center, Augusta University, Augusta, GA 30912, USA 3 Charlie Norwood VA Medical Center, Augusta, GA 30904, USA Correspondence to: Kebin Liu, email: Kliu@augusta.edu Keywords: CD133, CD24, colon cancer stem cells, 5-Fluorouracil Received: January 14, 2016 Accepted: September 12, 2016 Published: September 21, 2016 ABSTRACT The chemotherapeutic agent 5-Fluorouracil (5-FU) is the most commonly used drug for patients with advanced colon cancer. However, development of resistance to 5-FU is inevitable in almost all patients. The mechanism by which colon cancer develops 5-FU resistance is still unclear. One recently proposed theory is that cancer stem-like cells underlie colon cancer 5-FU resistance, but the phenotypes of 5-FU-resistant colon cancer stem cells are still controversial. We report here that 5-FU treatment selectively enriches a subset of CD133 + colon cancer cells in vitro . 5-FU chemotherapy also increases CD133 + tumor cells in human colon cancer patients. However, sorted CD133 + colon cancer cells exhibit no increased resistance to 5-FU, and CD133 levels exhibit no correlation with colon cancer patient survival or cancer recurrence. Genome-wide analysis of gene expression between sorted CD133 + colon cancer cells and 5-FU-selected colon cancer cells identifies 207 differentially expressed genes. CD24 is one of the genes whose expression level is lower in the CD133 + and 5-FU-resistant colon cancer cells as compared to CD133 + and 5-FU-sensitive colon cancer cells. Consequently, CD133 + CD24 lo cells exhibit decreased sensitivity to 5-FU. Therefore, we determine that CD133 + CD24 lo phenotype defines 5-FU-resistant human colon cancer stem cell-like cells.
TL;DR: This study reveals that β-AR2 functions as a tumor suppressor, underscoring its clinical importance in regulating CXCR7/EGFR–mediated tumor cell proliferation.
Abstract: The atypical 7-transmembrane chemokine receptor, CXCR7, transactivates the EGFR leading to increased tumor growth in several tumor types. However, the molecular mechanism of CXCR7 ligand–independent EGFR transactivation is unknown. We used cDNA knock-in, RNAi and analysis of mitogenic signaling components in both normal prostate epithelial cells and prostate cancer cells to decipher the proliferation-inducing mechanism of the CXCR7–EGFR interaction. The data demonstrate that CXCR7-induced EGFR transactivation is independent of both the release of cryptic EGFR ligands (e.g., AREG/amphiregulin) and G-protein–coupled receptor signaling. An alternate signaling mechanism involving β-arrestin-2 (ARRB2/β-AR2) was examined by manipulating the levels of β-AR2 and analyzing changes in LNCaP cell growth and phosphorylation of EGFR, ERK1/2, Src, and Akt. Depletion of β-AR2 in LNCaP cells increased proliferation/colony formation and significantly increased activation of Src, phosphorylation of EGFR at Tyr-1110, and phosphorylation/activation of ERK1/2 compared with that with control shRNA. Moreover, β-AR2 depletion downregulated the proliferation suppressor p21. Stimulation of β-AR2–expressing cells with EGF resulted in rapid nuclear translocation of phosphorylated/activated EGFR. Downregulation of β-AR2 enhanced this nuclear translocation. These results demonstrate that β-AR2 is a negative regulator of CXCR7/Src/EGFR–mediated mitogenic signaling.
Implications: This study reveals that β-AR2 functions as a tumor suppressor, underscoring its clinical importance in regulating CXCR7/EGFR–mediated tumor cell proliferation. Mol Cancer Res; 14(5); 493–503. ©2016 AACR .
This article is featured in Highlights of This Issue, [p. 409][1]
[1]: /lookup/volpage/14/409?iss=5
TL;DR: In this article, a sterically stabilized liposomal formulation of the PAK1 activation-3 (IPA-3) was used to inhibit prostate cancer cell growth in vitro with comparable efficacy to free IPA-3.
TL;DR: A central role of mitochondrial dysfunction is unraveled in a high fat diet-induced glomerulopathy and proximal tubular injury and the renoprotective effect of SS31, a mitochondria-targeted antioxidant, is demonstrated in related models.
TL;DR: This study provides evidence that deregulation of l-arginine metabolism plays a vital role in HFHS diet-induced diabetic complications and that these complications can be prevented by treatment with arginase inhibitors.
TL;DR: This study is the first to suggest that orosensory stimulation produced by consuming a sweetened solution and possibly the hedonic value of that sweet stimulation induces synaptic plasticity in dHC CA1 neurons in an experience‐dependent manner.
Abstract: There is limited knowledge regarding how the brain controls the timing of meals. Similarly, there is a large gap in our understanding of how top-down cognitive processes, such as memory influence energy intake. We hypothesize that dorsal hippocampal (dHC) neurons, which are critical for episodic memory, form a memory of a meal and inhibit meal onset during the postprandial period. In support, we showed previously that reversible inactivation of these neurons during the period following a sucrose meal accelerates the onset of the next meal. If dHC neurons form a memory of a meal, then consumption should induce synaptic plasticity in dHC neurons. To test this, we determined (1) whether a sucrose meal increases the expression of the synaptic plasticity marker activity-regulated cytoskeleton-associated protein (Arc) in dHC CA1 neurons, (2) whether previous experience with sucrose influences sucrose-induced Arc expression, and (3) whether the orosensory stimulation produced by the noncaloric sweetener saccharin is sufficient to induce Arc expression. Male Sprague-Dawley rats were trained to consume a sweetened solution at a scheduled time daily. On the experimental day, they were given a solution for 7 min, euthanized, and then fluorescence in situ hybridization procedures were used to measure meal-induced Arc mRNA. Compared to caged control rats, Arc expression was significantly higher in rats that consumed sucrose or saccharin. Interestingly, rats given additional experience with sucrose had less Arc expression than rats with less sucrose experience, even though both groups consumed similar amounts on the experimental day. Thus, this study is the first to suggest that orosensory stimulation produced by consuming a sweetened solution and possibly the hedonic value of that sweet stimulation induces synaptic plasticity in dHC CA1 neurons in an experience-dependent manner. Collectively, these findings are consistent with our hypothesis that dHC neurons form a memory of a meal.
TL;DR: The results of this analysis showed that MDL 72527 treatment significantly reduced hyperoxia-induced retinal vascular injury and enhanced vascular sprouting as compared with the vehicle controls, and protective effects were correlated with significant decreases in microglial activation as well as levels of inflammatory cytokines and chemokines.
TL;DR: This data suggests that different levels of anesthesia affect memory via different mechanisms: general anesthesia prevents elevation of mRNA levels of Arc and Zif268 which are necessary for normal memory formation, while anesthesia at lower doses affects the strength of memory by affecting levels of plasticity-related proteins.
Abstract: Background: Anterograde amnesia is a hallmark effect of volatile anesthetics. Isoflurane is known to affect both the translation and transcription of plasticity-associated genes required for normal memory formation in many brain regions. What is not known is whether isoflurane anesthesia prevents the initiation of transcription or whether it halts transcription already in progress. We tested the hypothesis that general anesthesia with isoflurane prevents learning-induced initiation of transcription of several memory-associated immediate-early genes (IEGs) correlated with amnesia; we also assessed whether it stops transcription initiated prior to anesthetic administration. Methods: Using a Tone Fear Conditioning paradigm, rats were trained to associate a tone with foot-shock. Animals received either no anesthesia, anesthesia immediately after training, or anesthesia before, during, and after training. Animals were either sacrificed after training or tested 24 hours later for memory. Using Cellular Compartment Analysis of Temporal Activity by Fluorescence in situ Hybridization (catFISH), we examined the percentage of neurons expressing the IEGs Arc/Arg3.1 and Zif268/Egr1/Ngfi-A/Krox-24 in the dorsal hippocampus, primary somatosensory cortex, and primary auditory cortex. Results: On a cellular level, isoflurane administered at high doses (general anesthesia) prevented initiation of transcription, but did not stop transcription of Arc and Zif268 mRNA initiated prior to anesthesia. On a behavioral level, the same level of isoflurane anesthesia produced anterograde amnesia for fear conditioning when administered before and during training, but did not produce retrograde amnesia when administered immediately after training. Conclusions: General anesthesia with isoflurane prevents initiation of learning-related transcription but does not stop ongoing transcription of two plasticity-related IEGs, Arc and Zif268, a pattern of disruption that parallels the effects of isoflurane on memory formation. Combined with published research on the effects of volatile anesthetics on memory in behaving animals, our data suggests that different levels of anesthesia affect memory via different mechanisms: general anesthesia prevents elevation of mRNA levels of Arc and Zif268 which are necessary for normal memory formation, while anesthesia at lower doses affects the strength of memory by affecting levels of plasticity-related proteins.