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1.
Adipocyte ; 11(1): 276-286, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35481427

RESUMEN

Type 2 Diabetes (T2D) is associated with impaired vascularization of adipose tissue (AT) . IL8, GROα and IL15 are pro-angiogenic myokines, secreted at elevated levels by T2D myotubes. We explored the direct impact of these myokines on AT vascularization. AT explants from subjects with T2D and without diabetes (non-diabetic, ND) were treated with rIL8, rGROα and rIL15 in concentrations equal to those in conditioned media (CM) from T2D and ND myotubes, and sprout formation evaluated. Endothelial cells (EC) were isolated from T2D and ND-AT, treated with rGROα and tube formation evaluated. Finally, we investigated the involvement of MMP-2 and -9 in vascularization. ND and T2D concentrations of IL8 or IL15   caused similar stimulation of sprout formation in ND- and T2D-AT. GROα exerted a similar effect in ND-AT. When T2D-AT explants were exposed to GROα, sprout formation in response to T2D concentrations was reduced compared to ND. Exposure of EC from T2D-AT to GROα at T2D concentrations resulted in reduced tube formation. Reduced responses to GROα in T2D-AT and EC were also seen for secretion of MMP-2 and -9. The data indicate that skeletal muscle can potentially regulate AT vascularization, with T2D-AT having impairments in sensitivity to GROα, while responding normally to IL8 and IL15.


Asunto(s)
Diabetes Mellitus Tipo 2 , Tejido Adiposo , Quimiocina CXCL1 , Diabetes Mellitus Tipo 2/complicaciones , Células Endoteliales , Humanos , Interleucina-15 , Interleucina-8 , Metaloproteinasa 2 de la Matriz , Metaloproteinasa 9 de la Matriz
2.
Mol Biol Rep ; 48(1): 601-610, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33411234

RESUMEN

Angiogenesis is a multistep process requiring endothelial cell activation, migration, proliferation and tube formation. We recently reported that elevated secretion of interlukin 8 (IL8) by myotubes (MT) from subjects with Type-2 Diabetes (T2D) reduced angiogenesis by human umbilical vein endothelial cells (HUVEC) and human skeletal muscle explants. This lower vascularization was mediated through impaired activation of the phosphatidylinositol 3-kinase (PI3K)-pathway. We sought to investigate additional signaling elements that might mediate reduced angiogenesis. HUVEC were exposed to levels of IL8 equal to those secreted by MT from non-diabetic (ND) and T2D subjects and the involvement of components in the angiogenic response pathway examined. Cellular content of reactive oxygen species and Nitrate secretion were similar after treatment with [ND-IL8] and [T2D-IL8]. CXCR1 protein was down-regulated after treatment with [T2D-IL8] (p < 0.01 vs [ND-IL8] treatment); CXCR2 expression was unaltered. Addition of neutralizing antibodies against CXCR1 and CXCR2 to HUVEC treated with IL8 confirmed that CXCR1 alone mediated the angiogenic response to IL8. A key modulator of angiogenesis is matrix metalloproteinase-2 (MMP2). MMP2 secretion was higher after treatment with [ND-IL8] vs [T2D-IL8] (p < 0.01). MMP2 inhibition reduced tube formation to greater extent with [ND-IL8] than with [T2D-IL8] (p < 0.005). The PI3K-pathway inhibitor LY294002 reduced IL8-induced MMP2 release. IL8 regulation of MMP2 release was CXCR1 dependent, as anti-CXCR1 significantly reduced MMP2 release (p < 0.05). These results suggest that high levels of IL8 secreted by T2D MT trigger reduced capillarization via lower activation of a CXCR1-PI3K pathway, followed by impaired release and activity of MMP2.


Asunto(s)
Diabetes Mellitus Tipo 2/genética , Interleucina-8/genética , Metaloproteinasa 2 de la Matriz/genética , Fibras Musculares Esqueléticas/metabolismo , Receptores de Interleucina-8A/genética , Movimiento Celular/genética , Proliferación Celular/genética , Células Cultivadas , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Células Endoteliales de la Vena Umbilical Humana , Humanos , Interleucina-8/farmacología , Fibras Musculares Esqueléticas/patología , Músculo Esquelético/crecimiento & desarrollo , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Neovascularización Patológica/genética , Neovascularización Patológica/patología , Fosfatidilinositol 3-Quinasas/genética , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/efectos de los fármacos
4.
J Immigr Minor Health ; 20(1): 51-58, 2018 02.
Artículo en Inglés | MEDLINE | ID: mdl-27796701

RESUMEN

Patients' preferences in choosing obstetricians/gynecologists are widely investigated, but studies among traditional populations are lacking. Bedouins comprise a traditional Arab Muslim society in the Arabian Peninsula (Saudi Arabia), The Levant (Syria, Jordan and Israel) and North Africa (Egypt). Most of the Bedouins in Israel populate several villages, mostly in the southern part of the country. This cross-sectional study compared 200 Bedouin and 200 Jewish women who responded to an anonymous questionnaire. Queried on gender alone, more Bedouin responders preferred female obstetricians/gynecologists (59.5 vs. 33% Jewish responders, p value <0.0001). Bedouin women preferred a female obstetrician/gynecologist for intimate procedures [feeling more comfortable (66.3%) and believing that females were more gentle (50%)]. However, they and the Jewish participants ranked ability, experience and knowledge as the top 3 qualities of an obstetrician/gynecologist, putting reputation in 4th place and gender in 5th place. Bedouin women strongly preferred female obstetricians/gynecologists, although professional skills were an important factor in their choice of caregiver. The ideal obstetrician/gynecologist for Bedouin women would be a skilled, knowledgeable, and experienced female.


Asunto(s)
Conducta de Elección , Ginecología , Obstetricia , Prioridad del Paciente , Relaciones Médico-Paciente , Adolescente , Adulto , Anciano , Femenino , Humanos , Islamismo , Persona de Mediana Edad , Encuestas y Cuestionarios , Adulto Joven
5.
Am J Mens Health ; 12(5): 1379-1383, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-27222116

RESUMEN

There are several studies on patients' preference for same-gender physicians, especially female preference for same-gender gynecologists. Data regarding the preferences of urology patients, of whom the majority are males, are scarce. The objective of this study is to assess provider gender preference among urology patients. One hundred and nineteen consecutive men (mean age 57.6 years) who attended a urology clinic in one university-affiliated medical center were prospectively enrolled. A self-accomplished 26-item anonymous questionnaire was used to assess patients' preferences in selecting their urologist. Of the 119 patients, 51 (42.8%) preferred a male urologist. Patients exhibited more same-gender preference for physical examination (38.3%), or urological surgery (35.3%), than for consultation (24.4%). Most patients (97%) preferred a same-gender urologist because they felt less embarrassed. Four patient characteristics were identified to be significantly associated with preference for a male urologist: religious status, country of origin, marital status, and a prior management by a male urologist. Of these, religious status was the most predictive parameter for choosing a male urologist. The three most important factors that affected actual selection, however, were professional skills (84.6%), clinical experience (72.4%), and medical knowledge (61%), rather than physician gender per se. Many male patients express gender bias regarding their preference for urologist. However, professional skills of the clinician are considered to be more important factors when it comes to actually making a choice.


Asunto(s)
Conducta de Elección , Participación del Paciente/psicología , Prioridad del Paciente/psicología , Relaciones Médico-Paciente , Adulto , Comunicación , Humanos , Masculino , Persona de Mediana Edad , Prioridad del Paciente/estadística & datos numéricos , Satisfacción del Paciente/estadística & datos numéricos , Estudios Prospectivos , Encuestas y Cuestionarios , Urólogos
6.
Artículo en Inglés | MEDLINE | ID: mdl-27980717

RESUMEN

BACKGROUND: Patient preferences regarding the gender of their physicians is a highly sensitive issue, which can be particularly salient in intimate medical situations. Previously published studies found that women tend to prefer female physicians, especially in the case of obstetricians and gynecologists. Data regarding other intimate specialties, such as breast surgery, are scarce. The present study was undertaken to assess gender preferences of women regarding their choice of a breast surgeon. METHODS: Five hundred and fifteen consecutive women who attended breast clinics in two university-affiliated tertiary hospitals were prospectively enrolled. A 25-item anonymous questionnaire was completed by women independently and used to assess their preferences in selecting their breast surgeon. Of the 515 women, 500 (97 % response rate; mean age 50.6 ± 15.4 years) completed the anonymous questionnaire. RESULTS: Overall, 160 (32 %) women preferred to undergo breast examination by a female breast surgeon, 296 (59 %) had no preference, and only 44 (9 %) preferred a male surgeon. A same-gender preference was significantly and independently associated with younger age of the patients (Odds Ratio = 0.978, 95 % Confidence Interval 0.962-0.994, P = 0.007) and being married (Odds Ratio = 0.563, 95 % Confidence Interval 0.347-0.916, P = 0.021). However, only small and equal numbers of patients preferred to undergo breast surgery by a female (14 %) or a male (13 %) surgeon, and most patients (73 %) had no gender preferences. Furthermore, the three most important factors, which affected in general the actual selection, were surgical ability (93 %), experience (91.2 %) and knowledge (78.6 %), rather than physician gender per se. CONCLUSIONS: Overall, about a third of women prefer a female breast surgeon for their breast examination. Embarrassment during the examination was the major reason for same-gender preference. In contrast, when it comes to breast operations, preference for a female surgeon is less pronounced, with the professional skills of the surgeons becoming the predominant consideration. The fact that almost a third of the potential patients prefer female surgeons with regard to their breast examinations emphasizes the need to increase the number of female surgeons. Such an increase can be achieved through academic and economic changes that will enable more women to specialize in general surgery. TRIAL REGISTRATION: Trial registration is not required for this type of research.


Asunto(s)
Mama/cirugía , Conducta de Elección , Oncología Médica , Prioridad del Paciente/psicología , Médicos Mujeres/provisión & distribución , Adulto , Anciano , Femenino , Humanos , Oncología Médica/estadística & datos numéricos , Persona de Mediana Edad , Prioridad del Paciente/estadística & datos numéricos , Relaciones Médico-Paciente , Médicos Mujeres/estadística & datos numéricos , Estudios Prospectivos , Factores Sexuales , Encuestas y Cuestionarios , Recursos Humanos
7.
Artículo en Inglés | MEDLINE | ID: mdl-26034576

RESUMEN

BACKGROUND: Consideration and better understanding of patients' needs on the part of the healthcare system might help increase the number of people seeking necessary medical care. Many studies have been conducted on patients' preferences in choosing their health care provider, but the majority of them were conducted in modern western societies, establishing a need to explore other populations. The present study was performed in the Israeli Druze community which is composed of a uniquely traditional and religious population. We assessed the sex preference of Israeli Druze women regarding obstetricians/gynecologists, and identify other features that affect their choice. METHOD: We conducted a cross-sectional study that included 196 Israeli Druze women who anonymously completed a 36-item questionnaire between January-July, 2011. RESULTS: Most (63.8%) of the responders preferred female obstetricians/gynecologists, while 74.5% had no sex preference for their family physicians. 68.6% of the religious women preferred female obstetricians/gynecologists as compared to 51.76% of those women who self-identified as secular. Most of the women (65%) preferred female obstetricians/gynecologists for intimate procedures, such as pelvic examination and pregnancy follow-up. The main reasons given were: feeling more comfortable with a female practitioner (69.7%), the belief that females are more gentle (56.6%), and being more embarrassed with male obstetricians/gynecologists (45.4%). Three factors were associated with the responders' preferences for female obstetricians/gynecologists: their age and religious status, and the sex of their regular obstetricians/gynecologists. Women who preferred a female obstetrician/gynecologist assigned a lesser weight to the physician's knowledge when choosing them. Older and religious women as well as those who attributed less weight to the physician's professional knowledge were more likely to prefer a female obstetrician/gynecologist. CONCLUSIONS: The majority of responders to our survey (Israeli Druze women), like those in other communities where religiousness and modesty are deeply rooted, prefer female obstetricians/gynecologists, with the overwhelming reasons given being feeling more comfortable and less embarrassed with females, and the notion that female obstetricians/gynecologists are more gentle during intimate procedures.

8.
Elife ; 4: e05914, 2015 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-25955862

RESUMEN

Skeletal integrity is maintained by the co-ordinated activity of osteoblasts, the bone-forming cells, and osteoclasts, the bone-resorbing cells. In this study, we show that mice overexpressing galectin-8, a secreted mammalian lectin of the galectins family, exhibit accelerated osteoclasts activity and bone turnover, which culminates in reduced bone mass, similar to cases of postmenopausal osteoporosis and cancerous osteolysis. This phenotype can be attributed to a direct action of galectin-8 on primary cultures of osteoblasts that secrete the osteoclastogenic factor RANKL upon binding of galectin-8. This results in enhanced differentiation into osteoclasts of the bone marrow cells co-cultured with galectin-8-treated osteoblasts. Secretion of RANKL by galectin-8-treated osteoblasts can be attributed to binding of galectin-8 to receptor complexes that positively (uPAR and MRC2) and negatively (LRP1) regulate galectin-8 function. Our findings identify galectins as new players in osteoclastogenesis and bone remodeling, and highlight a potential regulation of bone mass by animal lectins.


Asunto(s)
Células de la Médula Ósea/metabolismo , Resorción Ósea/genética , Huesos/metabolismo , Galectinas/genética , Osteoblastos/metabolismo , Osteoclastos/metabolismo , Ligando RANK/genética , Animales , Densidad Ósea/genética , Células de la Médula Ósea/citología , Resorción Ósea/metabolismo , Resorción Ósea/patología , Huesos/citología , Técnicas de Cocultivo , Femenino , Galectinas/metabolismo , Regulación de la Expresión Génica , Proteína 1 Relacionada con Receptor de Lipoproteína de Baja Densidad , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Ratones , Ratones Transgénicos , Osteoblastos/citología , Osteoclastos/citología , Osteogénesis/genética , Cultivo Primario de Células , Unión Proteica , Ligando RANK/metabolismo , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Receptores de LDL/genética , Receptores de LDL/metabolismo , Receptores del Activador de Plasminógeno Tipo Uroquinasa/genética , Receptores del Activador de Plasminógeno Tipo Uroquinasa/metabolismo , Transducción de Señal , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo
9.
Am J Physiol Endocrinol Metab ; 309(1): E22-34, 2015 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-25944879

RESUMEN

Reduced capillary density is a feature of skeletal muscle (SkM) in type 2 diabetes (T2D), which is associated with multiple metabolic and functional abnormalities. SkM has been identified as a secretory tissue, releasing myokines that regulate multiple processes, including vascularization. We sought to determine how myokines secreted from T2D myotubes might influence SkM angiogenesis. Conditioned media (CM) were generated by myotubes from T2D and nondiabetic (ND) subjects. Primary human endothelial cells (HUVEC) and SkM explants were exposed to CM or recombinant myokines, and tube number or capillary outgrowth was determined as well as measurement of protein expression and phosphorylation. CM from ND myotubes stimulated tube formation of HUVEC to a greater extent than T2D myotubes (T2D-CM = 100%, ND-CM = 288 ± 90% after 48 h, P < 0.05). The effects of T2D myotube CM were mediated by IL-8, not IL-15 or GROα, and were due not to cell damage but rather through regulating tube production and maintenance (response to T2D-IL-8 = 100%, response to ND-IL-8 = 263 ± 46% after 48 h, P < 0.05). A similar effect was seen in SkM explants with exposure to IL-8. The dose-dependent effect of IL-8 on tube formation was also observable in the PI3K and FAK signaling pathways and mediated at least in part by PI3K, leading to regulation of Tie2 expression. These results suggest that elevated levels of IL-8 secreted from T2D myotubes create a muscle microenvironment that supports reduced capillarization in T2D. Impaired vascularization of SkM limits the availability of substrates, including glucose and contributes to the T2D phenotype.


Asunto(s)
Diabetes Mellitus Tipo 2/metabolismo , Interleucina-8/metabolismo , Fibras Musculares Esqueléticas/fisiología , Músculo Esquelético/metabolismo , Fosfatidilinositol 3-Quinasas/fisiología , Receptor TIE-2/fisiología , Estudios de Casos y Controles , Proliferación Celular , Células Cultivadas , Diabetes Mellitus Tipo 2/patología , Femenino , Células Endoteliales de la Vena Umbilical Humana , Humanos , Interleucina-8/sangre , Masculino , Persona de Mediana Edad , Fibras Musculares Esqueléticas/patología , Músculo Esquelético/patología , Transducción de Señal/fisiología
10.
J Neuroimmunol ; 278: 85-9, 2015 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-25595256

RESUMEN

Leukemia inhibitory factor (LIF) is known to potentiate the differentiation and survival of neuronal and oligodendrocyte precursors. Systemic therapy with LIF reportedly ameliorated the severity of experimental autoimmune encephalomyelitis and prevented oligodendrocyte death. We studied the secreted LIF levels from immune cells of relapsing remitting multiple sclerosis (RR-MS) patients compared to age- and gender-matched healthy controls (HCs). LIF was barely detected in the supernatants when the cells were not stimulated. After stimulation with anti-CD3/CD28 monoclonal antibody, LIF levels were up-regulated in both patients and controls, although to a significantly lower extent in RR-MS patients compared to HC. There were no significant differences between untreated patients and interferon-ß1a treated patients. This is a heretofore unreported aspect of immune dysregulation in patients with RR-MS that may be related to insufficient remyelination and neurogenesis in MS lesions.


Asunto(s)
Factor Inhibidor de Leucemia/metabolismo , Leucocitos Mononucleares/metabolismo , Esclerosis Múltiple Recurrente-Remitente/inmunología , Esclerosis Múltiple Recurrente-Remitente/patología , Adulto , Antígenos CD/metabolismo , Estudios de Casos y Controles , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Tiempo
11.
J Obstet Gynaecol Res ; 41(2): 283-93, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25227636

RESUMEN

AIM: The aim of this study was to explore lesbians' preferences when choosing obstetricians/gynecologists. MATERIAL AND METHODS: This cross-sectional study included 100 lesbian and 100 heterosexual women. A 40-item questionnaire assessed the correlation between a patient's sexual identity and her specific preferences for obstetricians/gynecologists. RESULTS: The top five most important parameters for both groups in choosing obstetricians/gynecologists overlapped greatly. Four of those were experience, ability, knowledge and personality. Only one parameter differed: lesbians ranked 'sexually tolerant' as the third most important characteristic while heterosexuals ranked 'availability' as the fifth most important characteristic. Lesbians rated 'sexual tolerance' significantly higher than heterosexuals (P < 0.001). More lesbians (56%) preferred female obstetricians/gynecologists compared to heterosexuals (21%) (P < 0.001). When compared to heterosexuals, more lesbians preferred female obstetricians/gynecologists for intimate and non-intimate procedures (P < 0.001). But within the lesbian population, a higher percentage of subjects showed a preference for female obstetricians/gynecologists only for intimate procedures. Lesbians used the following to describe their preference for female obstetricians/gynecologists: feeling more comfortable; gentle; sympathetic; patient; more understanding of women's health; better physicians in general; and more sexually tolerant (P < 0.001 vs heterosexual). However, when we looked only at the lesbian population, the majority did not exhibit a preference for a female obstetrician/gynecologist for any of these reasons. The main reason given by the 56% of the lesbians who said they prefer female obstetricians/gynecologists was feeling more comfortable. CONCLUSION: Overwhelmingly lesbians prefer sexually tolerant obstetricians/gynecologists regardless of their gender; however, only a small number of lesbian subjects in this study considered their obstetricians/gynecologists as displaying this characteristic.


Asunto(s)
Homosexualidad Femenina/psicología , Prioridad del Paciente , Relaciones Médico-Paciente , Adolescente , Adulto , Anciano , Actitud del Personal de Salud , Conducta de Elección , Competencia Clínica , Estudios Transversales , Femenino , Ginecología , Accesibilidad a los Servicios de Salud , Humanos , Israel , Persona de Mediana Edad , Obstetricia , Personalidad , Factores Sexuales , Encuestas y Cuestionarios , Adulto Joven
12.
Mult Scler Int ; 2014: 926134, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25610650

RESUMEN

Background. The neural stem cells (NSCs) migrate to the damaged sites in multiple sclerosis (MS) and in experimental autoimmune encephalomyelitis (EAE). However, the differentiation into neurons or oligodendrocytes is blocked. Epidermal growth factor (EGF) stimulates NSC proliferation and mobilization to demyelinated lesions but also induces astrogenesis and glial scar. Objective. To examine the clinical and histopathological effects of EGF neutralization on EAE. Methods. EAE-induced SJL mice were intravenously treated with either anti-EGF neutralizing antibody (Ab) or isotype control or PBS. On day 9 after immunization, 3 mice of each group were daily treated for 9 days with BrdU and then sacrificed for immunohistochemical analysis. Results. Treatment with anti-EGF Ab significantly ameliorated EAE symptoms during the second relapse. Anti-EGF Ab induced a shift from BrdU(+)GFAP(+) NSCs to BrdU(+)DCX(+) neuroblasts in the subventricular zone (SVZ), increased BrdU(+)NeuN(+) neurons in the granular cell layer of the dentate gyrus, and increased BrdU(+)O4(+) oligodendrocytes in the SVZ. There was no change in the inflammatory infiltrates in response to anti-EGF Ab. Conclusions. Therapy with anti-EGF Ab ameliorates EAE via induction of neurogenesis and oligodendrogenesis. No immunosuppressive effect was found. Further investigation is needed to support these notions of beneficial effect of anti-EGF Ab in MS.

13.
J Neuroimmunol ; 257(1-2): 82-9, 2013 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-23466131

RESUMEN

We studied the secretion and regulation of epidermal growth factor (EGF) from immune cells of patients with relapsing remitting multiple sclerosis (RR-MS), and the relevance of these levels to neuronal morphology and survival. Our data suggest that the immune-mediated neuronal and oligodendroglial regeneration may be defective by the increased EGF secretion from immune cells of RR-MS patients. We also suggest an increased neurotoxicity of the immune response in RR-MS via high levels of EGF secretion. This is a heretofore unreported aspect of the immune response of patients with RR-MS. Our results may support the inadequate tissue repair that has been observed in MS.


Asunto(s)
Factor de Crecimiento Epidérmico/metabolismo , Inmunidad Celular , Esclerosis Múltiple Recurrente-Remitente/inmunología , Esclerosis Múltiple Recurrente-Remitente/metabolismo , Adulto , Animales , Células Cultivadas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Monocitos/inmunología , Monocitos/metabolismo , Monocitos/patología , Esclerosis Múltiple Recurrente-Remitente/patología , Células PC12 , Ratas , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Subgrupos de Linfocitos T/patología , Adulto Joven
14.
Glycobiology ; 16(6): 463-76, 2006 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16501058

RESUMEN

Galectin-8, a member of the galectin family of mammalian lectins, is made of two carbohydrate-recognition domains (CRDs), joined by a "hinge" region. Ligation of integrins by galectin-8 induces a distinct cytoskeletal organization, associated with activation of the extracellular-regulated kinase (ERK) and phosphatidylinositol 3-kinase signaling cascades. We show that these properties of galectin-8 are mediated by the concerted action of its two CRDs and involve both protein-sugar and protein-protein interactions. Accordingly, the isolated N- or C-CRD domains of galectin-8 or galectin-8 mutated at selected residues implicated in sugar binding (E251Q; W85Y, W248Y, W[85,248]Y) exhibited reduced sugar binding, which was accompanied by severe impairment in the capacity of these mutants to promote the adhesive, spreading, and signaling functions of galectin-8. Other mutations that did not impair sugar binding (e.g. E88Q) still impeded the signaling and cell-adherence functions of galectin-8. Deletion of the "hinge" region similarly impaired the biological effects of galectin-8. These results provide evidence that cooperative interactions between the two CRDs and the "hinge" domain are required for the proper functioning of galectin-8.


Asunto(s)
Adhesión Celular/fisiología , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Galectinas/fisiología , Animales , Células CHO , Forma de la Célula/fisiología , Cricetinae , Cricetulus , Galactosa/metabolismo , Galectinas/genética , Hemaglutinación/fisiología , Mutación , Fosforilación , Unión Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
15.
J Biol Chem ; 280(19): 19105-14, 2005 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-15753078

RESUMEN

Galectin-8, a mammalian beta-galactoside binding lectin, functions as an extracellular matrix protein that forms high affinity interactions with integrins. Here we demonstrated that soluble galectin-8 inhibits cell cycle progression and induces growth arrest. These effects cannot be attributed to interference with cell adhesion but can be attributed to a 4-5-fold increase in the cellular content of the cyclin-dependent kinase inhibitor p21, which was already evident following a 4-h incubation of H1299 cells with galectin-8. The increase in p21 levels was preceded by a 3-5-fold increase in JNK and protein kinase B (PKB) activities. Accordingly, SP600125, the inhibitor of JNK, and wortmannin, the inhibitor of phosphatidylinositol 3-kinase, which is the upstream activator of PKB, inhibited the increase in the cellular content of p21. Furthermore, overexpression of a dominant inhibitory form of SEK1, the upstream kinase regulator of JNK, inhibited both JNK activation and p21 accumulation. When p21 expression was inhibited by cycloheximide, galectin-8 directed the cells toward apoptosis, which involves induction of poly(ADP-ribose) polymerase cleavage. Indeed, galectin-8-induced apoptosis was 2-fold higher in HTC (p21-null) cells when compared with parental HTC cells. Because overexpression of galectin-8 attenuates the rate of DNA synthesis, stable colonies that overexpress and secrete galectin-8 can be generated only in cells overexpressing a growth factor receptor, such as the insulin receptor. These results implicate galectin-8 as a modulator of cellular growth through up-regulation of p21. This process involves activation of JNK, which enhances the synthesis of p21, combined with the activation of PKB, which inhibits p21 degradation. These effects of the lectin depended upon protein-sugar interactions and were induced when galectin-8 was present as a soluble ligand or when it was overexpressed in cells.


Asunto(s)
Apoptosis , Galectinas/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Inhibidores de Proteínas Quinasas/metabolismo , Androstadienos/farmacología , Animales , Antracenos/farmacología , Northern Blotting , Western Blotting , Bromodesoxiuridina/farmacología , Células CHO , Adhesión Celular , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Proliferación Celular , Cricetinae , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Cicloheximida/farmacología , ADN/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Ligandos , MAP Quinasa Quinasa 4 , Fosfatidilinositol 3-Quinasas/metabolismo , Poli(ADP-Ribosa) Polimerasas/metabolismo , Inhibidores de la Síntesis de la Proteína/farmacología , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Timidina/farmacología , Factores de Tiempo , Regulación hacia Arriba , Wortmanina
16.
J Biol Chem ; 278(16): 14533-42, 2003 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-12569102

RESUMEN

Galectin-8, a member of the galectin family of mammalian lectins, is a secreted protein that promotes cell adhesion and migration upon binding to a subset of integrins through sugar-protein interactions. Ligation of integrins by galectin-8 triggers a distinct pattern of cytoskeletal organization, including formation of F-actin-containing microspikes. This is associated with activation of integrin-mediated signaling cascades (ERK and phosphatidylinositol 3 kinase (PI3K)) that are much more robust and are of longer duration than those induced upon cell adhesion to fibronectin. Indeed, formation of microspikes is enhanced 40% in cells that overexpress protein kinase B, the downstream effector of PI3K. Inhibition of PI3K activity induced by wortmannin partially inhibits cell adhesion and spreading while largely inhibiting microspike formation in cells adherent to galectin-8. Furthermore, the inhibitory effects of wortmannin are markedly accentuated in cells overexpressing PKB or p70S6K (CHO(PKB) and CHO(p70S6K) cells), whose adhesion and spreading on galectin-8 (but not on fibronectin) is inhibited approximately 25-35% in the presence of wortmannin. The above results suggest that galectin-8 is an extracellular matrix protein that triggers a unique repertoire of integrin-mediated signals, which leads to a distinctive cytoskeletal organization and microspike formation. They further suggest that downstream effectors of PI3K, including PKB and p70 S6 kinase, in part mediate cell adhesion, spreading, and microspike formation induced by galectin-8.


Asunto(s)
Actinas/metabolismo , Galectinas/metabolismo , Integrinas/metabolismo , Lectinas/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Serina-Treonina Quinasas , Proteínas , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Animales , Células CHO , Adhesión Celular , Movimiento Celular , Cricetinae , Inhibidores Enzimáticos/farmacología , Fibronectinas/metabolismo , Humanos , Immunoblotting , Ratones , Microscopía Fluorescente , Fosfatidilinositol 3-Quinasas/metabolismo , Fosfoproteínas/metabolismo , Fosforilación , Pruebas de Precipitina , Unión Proteica , Proteínas Proto-Oncogénicas c-akt , Proteína p130 Similar a la del Retinoblastoma , Transducción de Señal , Factores de Tiempo
17.
Glycoconj J ; 19(7-9): 517-26, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-14758075

RESUMEN

Galectin-8 belongs to the family of tandem-repeat type galectins. It consists as several isoforms, each made of two domains of approximately 140 amino-acids, both having a carbohydrate recognition domain (CRD). These domains are joined by a 'link peptide' of variable length. The human galectin-8 gene covers 33 kbp of genomic DNA. It is localized on chromosome 1 (1q42.11) and contains 11 exons. The gene produces by alternative splicing 14 different transcripts, altogether encoding 6 proteins. Galectin-8, like other galectins, is a secreted protein. Upon secretion galectin-8 acts as a physiological modulator of cell adhesion. When immobilized, it functions as a matrix protein equipotent to fibronectin in promoting cell adhesion by ligation and clustering of a selective subset of cell surface integrin receptors. Complex formation between galectin-8 and integrins involves sugar-protein interactions and triggers integrin-mediated signaling cascades such as Tyr phosphorylation of FAK and paxillin. In contrast, when present in excess as a soluble ligand, galectin-8 (like fibronectin) forms a complex with integrins that negatively regulates cell adhesion. Such a mechanism allows local signals emitted by secreted galectin-8 to specify territories available for cell adhesion and migration. Due to its dual effects on the adhesive properties of cells and its association with fibronectin, galectin-8 might be considered as a novel type of a matricellular protein. Galectin-8 levels of expression positively correlate with certain human neoplasms, prostate cancer being the best example studied thus far. The overexpressed lectin might give these neoplasms some growth and metastasis related advantages due to its ability to modulate cell adhesion and cellular growth. Hence, galectin-8 may modulate cell-matrix interactions and regulate cellular functions in a variety of physiological and pathological conditions.


Asunto(s)
Galectinas/metabolismo , Animales , Adhesión Celular , División Celular , Galectinas/química , Galectinas/genética , Humanos , Integrinas/metabolismo , Neoplasias/metabolismo
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