Activation of phospholipase A2 and stimulation of prostaglandin E2 production by transforming growth factor-α in rat thymic epithelial cells requires influx of calcium

Liu, Pingsheng; Wen, Minghua; Sun, Le; Hayashi, Jun

doi:10.1042/bj2930109

Cited by 17 publications

(6 citation statements)

References 26 publications

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“…This result is consistent with previous studies that EGF caused [ 3 H]-AA release in human mesangial cells and rat mesangial cells in culture [45]. Activation of PLA 2 and subsequent stimulation of PGE 2 production requires the activation of EGF receptor tyrosine kinase and Ca 2+ influx in rat thymic epithelial cells [46]. In primary cultures of rabbit PTCs, EGF increases 5,6-EET, a major metabolite of cytochrome P-450 epoxygen-ase, which induces Ca 2+ influx [47].…”

Section: Discussionsupporting

confidence: 82%

Epidermal Growth Factor Regulates Ca2+ Uptake in Primary Cultured Renal Proximal Tubule Cells: Involvement of cAMP, PKC and cPLA2

Han

Park

Lee

2003

Kidney Blood Press Res

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Epidermal growth factor (EGF) is known to play an important role in modulating renal transport functions. Thus, we investigated the effect of EGF on Ca²⁺ uptake and its related signals in the primary cultured rabbit renal proximal tubule cells. EGF (50 ng/ml, 1 h) stimulated Ca²⁺ uptake. Its effect was blocked by AG 1478 (an EGF receptor antagonist), genistein or herbimycin A (tyrosine kinase inhibitors). EGF increased intracellular cAMP level and SQ 22536 (an adenylate cyclase inhibitor), Rp-cAMP (a cAMP analogue), or PKI (a protein kinase A inhibitor) blocked the EGF-induced stimulation of Ca²⁺ uptake. EGF-induced stimulation of Ca²⁺ uptake was also blocked by neomycin or U-73122 (phospholipase C inhibitors), staurosporine, H-7, or bisindolylmaleimide I (protein kinase C inhibitors), nifedipine or methoxyverapamil (L-type Ca²⁺ channel blockers). It increased IPs formation by 167 ± 5% compare to control within 90 s. On the other hand, EGF increased [³H]-arachidonic acid release, which was significantly blocked by PKC inhibitors. In addition, PGE₂, one of cyclooxygenase metabolites, and 5,6-EET, one of cytochrome P-450 metabolites, increased Ca²⁺ uptake. These results suggest that cAMP, PLC/PKC, and PLA₂ are involved in EGF-induced stimulation of Ca²⁺ uptake.

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Section: Discussionsupporting

confidence: 82%

Epidermal Growth Factor Regulates Ca2+ Uptake in Primary Cultured Renal Proximal Tubule Cells: Involvement of cAMP, PKC and cPLA2

Han

Park

Lee

2003

Kidney Blood Press Res

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“…TGF‐α and EGFR are critical modulators of cytokine production from human and mouse TEC and therefore they can regulate thymocyte proliferation and development 21, 28–30. Previous studies showed a causal relationship between the EGFR stimulation and subsequent PGE 2 release from TEC‐derived cell lines or TEC primary cultures from rodents 30, 31, although the COX isozyme accounting for PGE 2 release was not specified. On the other hand, it is known that EGFR enhances COX‐2‐dependent PGE 2 synthesis in many mammalian epithelial cells other than TEC, such as normal human epidermal keratinocytes 32, human bronchial epithelial cells 33, human squamous carcinoma cell lines 32.…”

Section: Discussionmentioning

confidence: 99%

Distinct expression of cyclooxygenase-1 and -2 in the human thymus

et al. 2002

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Cyclooxygenase (COX)‐1 and ‐2 catalyze the formation of prostaglandins (PG). Given the role of COX and PG during intrathymic T cell development in the mouse, we investigated the expression andlocalization of these isozymes in the human thymus. mRNA and proteins correspondent to COX‐1 and ‐2 were observed from whole thymus extracts. By immunohistochemistry, COX‐2 was selectively localized in the medulla and it was predominant in a subset of stromal cells. By contrast, COX‐1 was diffusely and exclusively present in the cortex, both in thymocytes at early stages of differentiation and in cytokeratin‐positive epithelial cells, as demonstrated by double immunostaining and flow cytometry analysis. COX‐2‐positive cells in the medulla expressed cytokeratin and HLA‐DR molecules, but they were negative for dendritic or macrophagic antigens. In addition, COX‐2‐positive cells expressed both the epidermal growth factor receptor and its ligand, the transforming growth factor‐α. The inducible isoform of the PGE2 synthase was also present in the same cells, while was absent from COX‐1‐expressing cells of the cortex. Finally, electron microscopy confirmed that COX‐2 was mainly localized in the cytoplasm of cytokeratin‐positive cells, along the rough endoplasmic reticulum. In conclusion, COX‐2 and the inducible isoform of PGE2 synthase appear to be constitutively and selectively present in medullary epithelial cells of the human thymus, whereas COX‐1 is predominantly present in the thymic cortex, both in the stroma and in developing thymocytes.

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“…During this early period, the number of lamina propria lymphocytes also increases and changes occur in the subsets of resident R and T lymphocytes [Rothkotter, 1991], EGF and TGFa have been implicated in thymus development [Andersen et al. 1993] and in stim ulation of cytokine [review: Le and Singer, 1993] and prostaglandin [Liu et al, 1993] production in thymic ep ithelial cells; the possibility that TGFa is involved in the maturation and function of developing lymphoid tissue in suckling pigs is intriguing.…”

Section: Discussionmentioning

confidence: 99%

Immunohistochemical Localization of Transforming Growth Factor-Alpha in Suckling Porcine Intestine

Jaeger

1996

Cells Tissues Organs

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The distribution of transforming growth factor-alpha (TGFα), a member of the epidermal growth factor (EGF) family, was studied immunohistochemically in small intestinal tissues of suckling pigs which were 7, 14 and 21 days of age. TGFα immunostaining was similar in villous epithelium in all intestinal regions of all ages examined, and was diffuse throughout the epithelial cytoplasm and more prominent in the apical and brush-border regions of the cells. Cytoplasmic immunoreactive TGFα was also identified in crypt epithelial cells; the pattern and extent of immunostaining differed among intestinal regions and ages. In all cases, the relative number of TGFα-immunopositive crypt epithelial cells was fewer than the number of immunonegative cells within the compartment. In duodenal and jejunal segments, relative numbers of immunopositive crypt epithelial cells were greater in 14- and 21- than in 7-day-old pigs. In all 7-day-old pigs, a relatively greater number of immunopositive epithelial cells was present in the jejunal crypts than in the duodenal crypts. Intracellular TGFα immunostaining was present within Peyer’s patches of distal jejunum and ileum, and is a previously unreported finding. The presence of TGFα immunoreactive protein within small intestinal crypt epithelium has not been previously described in any species, and may be unique to suckling animals or, alternatively, the porcine species. These data suggest that TGFα may be an endogenous ligand for the EGF receptor in suckling porcine intestine. Increased expression of TGFα in suckling pigs during the period in which marked structural and functional changes occur within the small intestinal mucosa suggests a role for this growth factor in remodelling and maturation of the neonatal mucosa.

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Activation of phospholipase A2 and stimulation of prostaglandin E2 production by transforming growth factor-α in rat thymic epithelial cells requires influx of calcium

Cited by 17 publications

References 26 publications

Epidermal Growth Factor Regulates Ca<sup>2+</sup> Uptake in Primary Cultured Renal Proximal Tubule Cells: Involvement of cAMP, PKC and cPLA<sub>2</sub>

Epidermal Growth Factor Regulates Ca<sup>2+</sup> Uptake in Primary Cultured Renal Proximal Tubule Cells: Involvement of cAMP, PKC and cPLA<sub>2</sub>

Distinct expression of cyclooxygenase-1 and -2 in the human thymus

Immunohistochemical Localization of Transforming Growth Factor-Alpha in Suckling Porcine Intestine

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