Cells encountering hypoxic stress conserve resources and energy by downregulating the protein synthesis. Here we demonstrate that one mechanism in this response is the translational repression of TOP mRNAs that encode...Cells encountering hypoxic stress conserve resources and energy by downregulating the protein synthesis. Here we demonstrate that one mechanism in this response is the translational repression of TOP mRNAs that encode components of the translational apparatus. This mode of regulation involves TSC and Rheb, as knockout of TSC1 or TSC2 or overexpression of Rheb rescued TOP mRNA translation in oxygen-deprived celts. Stress-induced translational repression of these mRNAs closely correlates with the hypophosphorylated state of 4E-BP, a translational repressor. However, a series of 4E-BP loss- and gain-of-function experiments disprove a cause-and- effect relationship between the phosphorylation status of 4E-BP and the translational repression of TOP mRNAs under oxygen or growth factor deprivation. Furthermore, the repressive effect of anoxia is similar to that attained by the very efficient inhibition of mTOR activity by Torin 1, but much more pronounced than roptor or rictor knockouL Likewise, deficiency of raptor or rictor, even though it mildly downregulated basal translation efficiency of TOP mRNAs, failed to suppress the oxygen-mediated translational activation of TOP mRNAs. Finally, co-knockdown of TIA-1 and TIAR, two RNA-binding proteins previously implicated in translational repression of TOP mRNAs in amino acid-starved cells, failed to relieve TOP mRNA translation under other stress conditions. Thus, the nature of the proximal translational regulator of TOP m RNAs remains elusive.展开更多
Background and aims:Crohn’s disease(CD)and intestinal tuberculosis(ITB)are both chronic granulomatous conditions with similar phenotypic presentations.Hence,there is need for a biomarker to differentiate between both...Background and aims:Crohn’s disease(CD)and intestinal tuberculosis(ITB)are both chronic granulomatous conditions with similar phenotypic presentations.Hence,there is need for a biomarker to differentiate between both these two diseases.This study aimed at genome-wide gene expression analysis of colonic biopsies from confirmed cases of ITB and CD in comparison with controls.To evaluate the role of T regulatory cells,forkhead box P3(FOXP3)mRNA expression was quantified in serum as well as in colonic biopsies from patients with ITB and with the controls.Methods:Paired samples,including serum and colonic biopsies,were taken from 33 study subjects(CD,ITB and controls),and total RNA was extracted.Human whole genome gene expression microarray analysis was performed using the Illumina HumanWG-6 BeadChip Kit with six total RNA samples of the three groups in duplicates.Real-time PCR for FOXP3 mRNA expression was analyzed in serum samples and colonic biopsy samples(4-CD,5-ITB,4-controls).Results:In CD and ITB there was 1.5-fold upregulation of 92 and 382 genes and 1.5-fold downregulation of 91 and 256 genes,respectively.Peroxisome proliferators via the PPARc pathway were most significantly downregulated(P<0.005)in CD.Additionally,the IL4/5/6 signaling pathways and Toll-like receptor signaling pathway were identified as significantly differentially regulated(P<0.005)at>2-fold change.In ITB,the complement activation pathway,specifically the classical pathway,was the most significantly upregulated.FOXP3 mRNA expression was significantly elevated in colonic biopsies obtained from ITB patients as compared with CD cases(4.7062.21 vs 1.4860.31,P=0.016).Conclusions:FOXP3 mRNA expression in colonic mucosa could be a discriminatory marker between ITB and CD.Upregulation of the complement activation pathway in ITB suggests that pathogenetic mechanisms for ITB are similar to those of pulmonary tuberculosis.In CD,downregulation of PPARc was seen in colonic tissue,suggesting that restoration of PPARc-dependent anti-microbial barrier function may be a therapeutic target.展开更多
APOBEC3 protein families, a DNA cytidine deaminase, were up-regulated in multiple tumors. However, the relationship between Hepatocellular carcinoma(HCC) and APOBEC3B(A3B) remains unknown. It has been confirmed that i...APOBEC3 protein families, a DNA cytidine deaminase, were up-regulated in multiple tumors. However, the relationship between Hepatocellular carcinoma(HCC) and APOBEC3B(A3B) remains unknown. It has been confirmed that interleukin-6(IL-6)has significant impacts on oncogenesis of HCC. Here, we reported that the expression of IL-6 was substantially up-regulated by A3 B in HepG2 cells. A3 B induced IL-6 expression through relocating HuR to enhance the IL-6 mRNA stability. Further analysis indicated that IL-6 also increased the expression of A3 B through JAK1/STAT3 signaling pathway, which formed a positive feedback to maintain the continuous expression of A3 B and IL-6, and thereby promoted the prolonged non-resolving inflammation. Collectively, these findings suggest that A3 B is essential for oncogenesis of HCC, and is a potential target for preventive intervention.展开更多
文摘Cells encountering hypoxic stress conserve resources and energy by downregulating the protein synthesis. Here we demonstrate that one mechanism in this response is the translational repression of TOP mRNAs that encode components of the translational apparatus. This mode of regulation involves TSC and Rheb, as knockout of TSC1 or TSC2 or overexpression of Rheb rescued TOP mRNA translation in oxygen-deprived celts. Stress-induced translational repression of these mRNAs closely correlates with the hypophosphorylated state of 4E-BP, a translational repressor. However, a series of 4E-BP loss- and gain-of-function experiments disprove a cause-and- effect relationship between the phosphorylation status of 4E-BP and the translational repression of TOP mRNAs under oxygen or growth factor deprivation. Furthermore, the repressive effect of anoxia is similar to that attained by the very efficient inhibition of mTOR activity by Torin 1, but much more pronounced than roptor or rictor knockouL Likewise, deficiency of raptor or rictor, even though it mildly downregulated basal translation efficiency of TOP mRNAs, failed to suppress the oxygen-mediated translational activation of TOP mRNAs. Finally, co-knockdown of TIA-1 and TIAR, two RNA-binding proteins previously implicated in translational repression of TOP mRNAs in amino acid-starved cells, failed to relieve TOP mRNA translation under other stress conditions. Thus, the nature of the proximal translational regulator of TOP m RNAs remains elusive.
基金This project was undertaken under the‘FIST’scheme of Department of Science and Technology,Government of India.In addition,support was taken from ICMR Senior Research Fellowship granted to VM.
文摘Background and aims:Crohn’s disease(CD)and intestinal tuberculosis(ITB)are both chronic granulomatous conditions with similar phenotypic presentations.Hence,there is need for a biomarker to differentiate between both these two diseases.This study aimed at genome-wide gene expression analysis of colonic biopsies from confirmed cases of ITB and CD in comparison with controls.To evaluate the role of T regulatory cells,forkhead box P3(FOXP3)mRNA expression was quantified in serum as well as in colonic biopsies from patients with ITB and with the controls.Methods:Paired samples,including serum and colonic biopsies,were taken from 33 study subjects(CD,ITB and controls),and total RNA was extracted.Human whole genome gene expression microarray analysis was performed using the Illumina HumanWG-6 BeadChip Kit with six total RNA samples of the three groups in duplicates.Real-time PCR for FOXP3 mRNA expression was analyzed in serum samples and colonic biopsy samples(4-CD,5-ITB,4-controls).Results:In CD and ITB there was 1.5-fold upregulation of 92 and 382 genes and 1.5-fold downregulation of 91 and 256 genes,respectively.Peroxisome proliferators via the PPARc pathway were most significantly downregulated(P<0.005)in CD.Additionally,the IL4/5/6 signaling pathways and Toll-like receptor signaling pathway were identified as significantly differentially regulated(P<0.005)at>2-fold change.In ITB,the complement activation pathway,specifically the classical pathway,was the most significantly upregulated.FOXP3 mRNA expression was significantly elevated in colonic biopsies obtained from ITB patients as compared with CD cases(4.7062.21 vs 1.4860.31,P=0.016).Conclusions:FOXP3 mRNA expression in colonic mucosa could be a discriminatory marker between ITB and CD.Upregulation of the complement activation pathway in ITB suggests that pathogenetic mechanisms for ITB are similar to those of pulmonary tuberculosis.In CD,downregulation of PPARc was seen in colonic tissue,suggesting that restoration of PPARc-dependent anti-microbial barrier function may be a therapeutic target.
基金supported in part by the National Natural Science Foundation of China (91529304, 81502407, 81473230, 81273547, 81403020 and 91129731)the Jiangsu Province Natural Science Foundation of China (BK2014666)the Central College Fund (ZJ14020)
文摘APOBEC3 protein families, a DNA cytidine deaminase, were up-regulated in multiple tumors. However, the relationship between Hepatocellular carcinoma(HCC) and APOBEC3B(A3B) remains unknown. It has been confirmed that interleukin-6(IL-6)has significant impacts on oncogenesis of HCC. Here, we reported that the expression of IL-6 was substantially up-regulated by A3 B in HepG2 cells. A3 B induced IL-6 expression through relocating HuR to enhance the IL-6 mRNA stability. Further analysis indicated that IL-6 also increased the expression of A3 B through JAK1/STAT3 signaling pathway, which formed a positive feedback to maintain the continuous expression of A3 B and IL-6, and thereby promoted the prolonged non-resolving inflammation. Collectively, these findings suggest that A3 B is essential for oncogenesis of HCC, and is a potential target for preventive intervention.
