liu.seSearch for publications in DiVA
Change search
Link to record
Permanent link

Direct link
BETA
Xu, Lihua
Publications (7 of 7) Show all publications
Yuan, X.-M., Osman, E., Miah, S., Zadeh, S. N., Xu, L., Forssell, C. & Li, W. (2010). p53 expression in human carotid atheroma is significantly related to plaque instability and clinical manifestations. Atherosclerosis, 210(2), 392-399
Open this publication in new window or tab >>p53 expression in human carotid atheroma is significantly related to plaque instability and clinical manifestations
Show others...
2010 (English)In: Atherosclerosis, ISSN 0021-9150, E-ISSN 1879-1484, Vol. 210, no 2, p. 392-399Article in journal (Refereed) Published
Abstract [en]

OBJECTIVE: The expression of p53 has been associated with DNA damage, cell senescence, proliferation and apoptosis in human atherosclerotic plaques. However, it is largely unknown whether p53 expression is related to the stability and clinical manifestations of atherosclerotic plaques in humans. In the present study, we examined whether p53 expression is related to clinical symptoms and plaque integrity in patients with carotid atherosclerosis (n=62). We also investigated p53 expression and its relation to apoptosis and apoptosis-related cathepsin L and ferritin in the carotid lesions. METHODS AND RESULTS: We found that smooth muscle cells often had nuclear p53 in the shoulder region of carotid lesions while CD68-positive macrophages, which had both nuclear and cytoplasmic p53, frequently appeared in the surrounding areas of necrotic cores or plaque cap regions. Quantitative image analysis of immunohistochemistry showed that p53 expression was significantly increased in plaques with necrotic core formation or cap rupture and lesions from patients with transient ischemic attacks (TIAs). The levels of p53 expression was significantly increased in more severe stenosed lesions but decreased with prolonged time between symptom onset and carotid endarterectomy. Furthermore, p53 expression was significantly correlated with the expression of ferritin, lysosomal cathepsin L, and apoptosis. CONCLUSION: The increased p53 expression, particularly macrophage p53 levels, is associated with the enlargement of necrotic cores, plaque rupture and clinical manifestations of carotid plaques. Concomitant increases of lysosomal cathepsin, ferritin, and p53 levels may promote the apoptosis and atheroma progression in patients with carotid atherosclerosis.

Keywords
Atherosclerosis, Cathepsin, Cell death, Ferritin, Iron, Lysosomes
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:liu:diva-56719 (URN)10.1016/j.atherosclerosis.2009.11.048 (DOI)000278036800013 ()20060114 (PubMedID)
Available from: 2010-06-01 Created: 2010-06-01 Last updated: 2018-01-12
Persson, K., Sauma, L., Safholm, A., Xu, L., Li, W. & Yuan, X. (2009). LDL and UV-oxidized LDL induce upregulation of iNOS and NO in unstimulated J774 macrophages and HUVEC. Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), 117(1), 1-9
Open this publication in new window or tab >>LDL and UV-oxidized LDL induce upregulation of iNOS and NO in unstimulated J774 macrophages and HUVEC
Show others...
2009 (English)In: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, E-ISSN 1600-0463, Vol. 117, no 1, p. 1-9Article in journal (Refereed) Published
Abstract [en]

Oxidized low-density lipoprotein (LDL) diminishes NO production from activated macrophages. The interaction between LDL and inactivated macrophages is neglected and controversial. This study examines the effect of LDL, 7-oxysterols and iron compounds on NO production in unstimulated J774 macrophages. J774 cells and human umbilical vein endothelial cells (HUVEC) were either incubated for 24 h with native LDL (LDL) or ultraviolet (UV)-oxidized LDL (UVoxLDL), in the absence or presence of an inducible nitric oxide synthase (iNOS)- or an endothelial constitutive nitric oxide synthase (eNOS)-inhibitor. J774 cells were also incubated with lipopolysaccharide (LPS), in the absence or presence of an iNOS- or an eNOS-inhibitor. Nitrite was analysed as a marker of NO production. The mRNA levels of iNOS were evaluated by reverse transcriptase polymerase chain reaction. LDL and UVoxLDL significantly increased NO production from unstimulated J774 macrophages. This increase in NO was accompanied by enhanced expression of iNOS mRNA, and was inhibited by the iNOS inhibitor. Furthermore, NO production was elevated and angiotensin-converting enzyme (ACE) activity was reduced in HUVEC following the exposure to LDL and UVoxLDL. In conclusion, LDL may serve as an important inflammatory activator of macrophages and HUVEC, inducing inducible nitric oxide production but diminishing ACE. After its oxidation, this function of LDL may be further enhanced and may contribute to the regulation and progression of atheroma formation.

Keywords
Low-density lipoprotein, macrophages, iNOS, nitric oxide
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-16631 (URN)10.1111/j.1600-0463.2008.00001.x (DOI)
Available from: 2009-02-08 Created: 2009-02-06 Last updated: 2017-12-14Bibliographically approved
Li, W., Xu, L., Forssell, C., Sullivan, J. & Yuan, X. (2008). Overexpression of transferrin receptor and ferritin related to clinical symptoms and destabilization of human carotid plaques. Experimental biology and medicine (Maywood, N.J.: Print), 233(7), 818-826
Open this publication in new window or tab >>Overexpression of transferrin receptor and ferritin related to clinical symptoms and destabilization of human carotid plaques
Show others...
2008 (English)In: Experimental biology and medicine (Maywood, N.J.: Print), ISSN 1535-3702, E-ISSN 1535-3699, Vol. 233, no 7, p. 818-826Article in journal (Refereed) Published
Abstract [en]

Accumulation of tissue iron has been implicated in development of atherosclerotic lesions mainly because of increased iron-catalyzed oxidative injury. However, it remains unknown whether cellular iron import and storage in human atheroma are related to human atheroma development. We found that transferrin receptor 1 (TfR1), a major iron importer, is highly expressed in foamy macrophages and some smooth muscle cells in intimal lesions of human carotid atheroma, mainly in cytoplasmic accumulation patterns. In 52 human carotid atherosclerotic lesions, TfR1 expression was positively correlated with macrophage infiltration, ectopic lysosomal cathepsin L, and ferritin expression. Highly expressed TfR1 and ferritin in CD68-positive macrophages were significantly associated with development and severity of human carotid plaques, smoking, and patient's symptoms. The findings suggest that pathologic macrophage iron metabolism may contribute to vulnerability of human atheroma, established risk factors, and their clinical symptoms. The cytoplasmic overexpression of TfR1 may be the result of lysosomal dysfunction and ectopic accumulation of lysosomal cathepsin I caused by atheroma-relevant lipids in atherogenesis. Copyright © 2008 by the Society for Experimental Biology and Medicine.

Keywords
Apoptosis, Atherosclerosis, Iron metabolism, Lysosomes, Macrophages, Plaque rupture
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-45822 (URN)10.3181/0711-RM-320 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13Bibliographically approved
Li, W., Östblom, M., Xu, L., Hellsten, A., Leanderson, P., Liedberg, B., . . . Yuan, X. (2006). Cytocidal effects of atheromatous plaque components: The death zone revisited. The FASEB Journal, 20(13), 2281-2290
Open this publication in new window or tab >>Cytocidal effects of atheromatous plaque components: The death zone revisited
Show others...
2006 (English)In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 20, no 13, p. 2281-2290Article in journal (Refereed) Published
Abstract [en]

Objective: Earlier we suggested that atheroma lesions constitute a "death zone" containing toxic materials that may cause dysfunction and demise of invading macrophages to prevent the removal of plaque materials. Here we have assessed the cytotoxic effects of nonfractionated gruel and insoluble (ceroid-like) material derived from advanced human atheroma. Methods and Results: The insoluble material within advanced atherosclerotic plaque was isolated following protease K digestion and extensive extraction with aqueous and organic solvents. FTIR, Raman, and atomic absorption spectroscopy suggested that, despite its fluorescent nature, this material closely resembled hydroxyapatite and dentin, but also contained a significant amount of iron and calcium. When added to J774 cells and human macrophages in culture, this insoluble substance was phagocytosed, and progressive cell death followed. However, an even more cytotoxic activity was found in the atheromatous "gruel" that contains abundant carbonyls/aldehydes. Cell death caused by both crude gruel and ceroid could be blocked by preincubating cells with the lipophilic iron chelator salicylaldehyde isonicotinoyl hydrazone, apoferritin, BAPTA/AM, or sodium borohydride, indicating that cellular iron, calcium, and reactive aldehyde(s) are responsible for the observed cytotoxicity. Conclusions: Toxic materials within atheromatous lesions include both ceroid and even more cytotoxic lipidaceous materials. The cytotoxic effects of these plaque components may help explain the persistence of atherosclerotic lesions. © FASEB.

Keywords
Apoferritin, Apoptosis, Atherosclerosis, Carbonyls, Ceroid, Iron, Macrophages
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-50100 (URN)10.1096/fj.06-6114com (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Li, W., Östblom, M., Xu, L., Hellsten, A., Leanderson, P., Liedberg, B., . . . Yuan, X. M. (2006). Cytocidal effects of atheromatous plaque components: the death zone revisited.. The FASEB Journal, 20, 2281-2290
Open this publication in new window or tab >>Cytocidal effects of atheromatous plaque components: the death zone revisited.
Show others...
2006 (English)In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 20, p. 2281-2290Article in journal (Refereed)
Abstract [en]

   

Identifiers
urn:nbn:se:liu:diva-35728 (URN)28331 (Local ID)28331 (Archive number)28331 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
Li, W., Hellsten, A., Xu, L., Zhuang, D.-M., Jansson, K., Brunk, U. & Yuan, X. M. (2005). Foam cell death induced by 7β-hydroxycholesterol is mediated by labile iron-driven oxidative injury: Mechanisms underlying induction of ferritin in human atheroma. Free Radical Biology & Medicine, 39(7), 864-875
Open this publication in new window or tab >>Foam cell death induced by 7β-hydroxycholesterol is mediated by labile iron-driven oxidative injury: Mechanisms underlying induction of ferritin in human atheroma
Show others...
2005 (English)In: Free Radical Biology & Medicine, ISSN 0891-5849, E-ISSN 1873-4596, Vol. 39, no 7, p. 864-875Article in journal (Refereed) Published
Abstract [en]

Human atherosclerotic lesions typically contain large amounts of ferritin associated with apoptotic macrophages and foam cells, although the reasons are unknown. In the present investigation, we studied the relationship between ferritin induction and occurrence of apoptosis in 7β-hydroxycholesterol (7β-OH)-treated monocytic cells and macrophages. We found that 7β-OH enlarges the intracellular labile iron pool, increases formation of reactive oxygen species (ROS), and induces ferritin and cytosolic accumulation of lipid droplets, lysosomal destabilization, and apoptototic macrophage death. Since ferritin is a phase II-type protective protein, our findings suggest that ferritin upregulation here worked as an inefficient defense mechanism. Addition to the culture medium of both a membrane-permeable iron chelator 10-phenanthroline and the non-membrane-permeable iron chelators apoferritin and desferrioxamine afforded significant protection against the 7β-OH-induced effects. Consequently, endocytosed iron compounds dramatically augmented 7β-OH-induced cytotoxicity. We conclude that oxidized lipid 7β-OH causes not only foam cell formation but also oxidative damage with abnormal metabolism of cellular iron. The findings suggest that modulation of iron metabolism in human atheroma may be a potential therapeutic strategy against atherosclerosis. © 2005 Elsevier Inc. All rights reserved.

Keywords
atherosclerosis, macrophage death, labile iron pool, lysosomes, oxysterols, ROS
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-29373 (URN)10.1016/j.freeradbiomed.2005.05.006 (DOI)14705 (Local ID)14705 (Archive number)14705 (OAI)
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13
Li, W., Xu, L. & Yuan, X. (2004). Macrophage hemoglobin scavenger receptor and ferritin accumulation in human atherosclerotic lesions. Annals of the New York Academy of Sciences, 1030, 196-201
Open this publication in new window or tab >>Macrophage hemoglobin scavenger receptor and ferritin accumulation in human atherosclerotic lesions
2004 (English)In: Annals of the New York Academy of Sciences, ISSN 0077-8923, E-ISSN 1749-6632, Vol. 1030, p. 196-201Article in journal (Refereed) Published
Abstract [en]

We previously proposed that erythrophagocytosis and iron metabolism by macrophages may contribute to iron-driven oxidative stress in atherogenesis. Recent studies have indicated that the macrophage hemoglobin scavenger receptor (HbSR/CD 163) is a key molecule in the process of removing hemoglobin released from senescent erythrocytes. In this study we investigated crythrophagocytosis and its relation to ferritin accumulation and the involvement of CD163 in ferritin induction in human atheroma lesions. Normal and atherosclerotic human arterial segments obtained at autopsy and surgery were collected for iron histochemistry, hemoglobin and ferritin immunohistochemistry, and computerized image analysis. The lesion-dependent accumulation of ferritin and hemoglobin was seen in atherosclerotic carotid and coronary arteries. The immunoreactivity of hemoglobin was significantly correlated to the same regions of ferritin immunoreactivity on serial sections. The staining intensity of hemoglobin and ferritin was also significantly correlated. Hemoglobin deposition is often associated with microvessels adjacent to the lipid core areas in advanced lesions, where most CD68-positive macrophages were. CD163 expression appeared in both early and advanced lesions. The accumulation of tissue iron and ferritin also frequently occurs in CD163-positive and vessel-rich regions in the advanced atheroma. Although they were not always correspondingly positive on the serial sections, tissue iron and ferritin were significantly correlated. We conclude that erythrophagocytosis and hemoglobin catabolism by macrophages contribute to iron deposition and ferritin induction in human atheroma. The involvement of CD163 during ferritin induction may play an important role in modulating inflammatory processes in atherogenesis.

Keywords
atherosclerosis, angiogenesis, erythrophagocytosis, ferritin, hemoglobin scavenger receptor, iron
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-46095 (URN)10.1196/annals.1329.025 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
Organisations

Search in DiVA

Show all publications