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1.
Neurología (Barc., Ed. impr.) ; 39(4): 329-339, May. 2024. ilus, tab, graf
Article in English | IBECS | ID: ibc-232515

ABSTRACT

Introduction: In the present study, anticonvulsant effects of aqueous extract (AE), hydro-alcoholic crude extract (HE), and its fractions (F-CHCl3, F-EtOAc, F-MeOH) of Paeonia daurica subsp. macrophylla (P. daurica ssp. macrophylla) root examined by using a pentylenetetrazol-induced model (PTZ) on mice. Methods: HE and its fractions as well as AE, in concentrations of (100, 200 and 400 mg/kg), valproate (Val) (100 and 200 mg/kg), and saline (negative control) (10 mg/kg) were injected intraperitoneally (i.p.) 30 min before PTZ (80 mg/kg, i.p.). The time taken before the onset of myoclonic convulsions (MC), MC duration, time taken before the onset of generalized tonic-clonic seizures (GTCS), the duration of GTCS, and the percentage of GTCS and mortality protection recorded. The plant's anticonvulsant mechanisms were assessed using flumazenil (5 mg/kg, i.p.) before AE (100, 200, and 400 mg/kg, i.p.) injection. GraphPad Prism software was used to compare the differences between various treatment groups with one-way analysis of variance (ANOVA) followed by Tukey–Krammer multiple comparison tests. Results: All the plant samples except F-EtOAc significantly delayed the onset and decreased the duration of PTZ-induced MCS and GTCS, and significantly reduced the GTCS and mortality rate. Pretreatment with flumazenil diminished the significant anticonvulsant effects of AE against PTZ-induced seizures. Conclusions: It can report that extract of P. daurica ssp. macrophylla might be a helpful guide for future studies in the treatment of epilepsy.(AU)


Introducción: Epilepsia es el término usado para un grupo de trastornos caracterizado por las convulsiones espontáneas recurrentes. Un estudio enfocado en los productos naturales de los recursos tradicionales ofrece ventajas significativas que se están utilizando de manera más amplia en modelos animales de epilepsia y candidatos a mayor desarrollo clínico y sus fracciones (F-CHCl3, F-EtOAc, F-MeOH) de Paeonia daurica subsp. macrophylla (P. daurica ssp. macrophylla) raíz examinada utilizando un modelo inducido por pentilentetrazol (PTZ) en ratones. Métodos: La maceración dinámica utilizada para extraer HE de la planta y técnica de cromatografía en columna de sílice utilizada para obtener F-CHCl3, F-EtOAc, así como fracciones de F-MeOH. La extracción de raíces secas se utilizó con agua destilada y se provocó AE. Las muestras de plantas (100, 200 y 400 mg/kg), valproato (Val) (100 y 200 mg/kg) y suero (control negativo) se inyectaron por vía intraperitoneal (ip) 30 min antes de PTZ (80 mg/kg, ip). El tiempo transcurrido antes del comienzo de convulsiones mioclónicas (MC), duración de las MC, tiempo transcurrido antes del comienzo de convulsiones tónico-clónicas generalizadas (GTCS), la duración de GTCS, así como el porcentaje de GTCS y protección contra la mortalidad registrada. Los mecanismos anticonvulsivos de planta fueron evaluados mediante el uso de flumazenil (5 mg/kg, ip) antes de AE (100, 200 y 400 mg/kg, ip) inyección. Se utilizaba el software GraphPad Prism® comparando las diferencias entre varios grupos de tratamiento con un análisis unilateral de variación (ANOVA) seguido por las pruebas de comparación múltiple de Tukey's Krammer. Resultados: Todas las muestras de plantas, excepto F-EtOAc, retrasaron de manera considerable el inicio, y disminuyeron la duración de PTZ inducidos por MCS y GTCS, y redujo significativamente el GTCS, así como la tasa de mortalidad...(AU)


Subject(s)
Animals , Anticonvulsants , Seizures , Epilepsy/drug therapy , Flumazenil/therapeutic use , Receptors, GABA , Paeonia , Neurology , Nervous System Diseases , Models, Animal
2.
Neurologia (Engl Ed) ; 39(4): 329-339, 2024 May.
Article in English | MEDLINE | ID: mdl-38616060

ABSTRACT

INTRODUCTION: In the present study, anticonvulsant effects of aqueous extract (AE), hydro-alcoholic crude extract (HE), and its fractions (F-CHCl3, F-EtOAc, F-MeOH) of Paeonia daurica subsp. macrophylla (P. daurica ssp. macrophylla) root examined by using a pentylenetetrazol-induced model (PTZ) on mice. METHODS: HE and its fractions as well as AE, in concentrations of (100, 200 and 400mg/kg), valproate (Val) (100 and 200mg/kg), and saline (negative control) (10mg/kg) were injected intraperitoneally (i.p.) 30min before PTZ (80mg/kg, i.p.). The time taken before the onset of myoclonic convulsions (MC), MC duration, time taken before the onset of generalized tonic-clonic seizures (GTCS), the duration of GTCS, and the percentage of GTCS and mortality protection recorded. The plant's anticonvulsant mechanisms were assessed using flumazenil (5mg/kg, i.p.) before AE (100, 200, and 400mg/kg, i.p.) injection. GraphPad Prism software was used to compare the differences between various treatment groups with one-way analysis of variance (ANOVA) followed by Tukey-Krammer multiple comparison tests. RESULTS: All the plant samples except F-EtOAc significantly delayed the onset and decreased the duration of PTZ-induced MCS and GTCS, and significantly reduced the GTCS and mortality rate. Pretreatment with flumazenil diminished the significant anticonvulsant effects of AE against PTZ-induced seizures. CONCLUSIONS: It can report that extract of P. daurica ssp. macrophylla might be a helpful guide for future studies in the treatment of epilepsy.


Subject(s)
Anticonvulsants , Paeonia , Animals , Mice , Anticonvulsants/pharmacology , Anticonvulsants/therapeutic use , Pentylenetetrazole/toxicity , Flumazenil , Seizures/chemically induced , Seizures/drug therapy
3.
Neurologia (Engl Ed) ; 2021 Sep 09.
Article in English, Spanish | MEDLINE | ID: mdl-34511273

ABSTRACT

INTRODUCTION: In the present study, anticonvulsant effects of aqueous extract (AE), hydro-alcoholic crude extract (HE), and its fractions (F-CHCl3, F-EtOAc, F-MeOH) of Paeonia daurica subsp. macrophylla (P. daurica ssp. macrophylla) root examined by using a pentylenetetrazol-induced model (PTZ) on mice. METHODS: HE and its fractions as well as AE, in concentrations of (100, 200 and 400mg/kg), valproate (Val) (100 and 200mg/kg), and saline (negative control) (10mg/kg) were injected intraperitoneally (i.p.) 30min before PTZ (80mg/kg, i.p.). The time taken before the onset of myoclonic convulsions (MC), MC duration, time taken before the onset of generalized tonic-clonic seizures (GTCS), the duration of GTCS, and the percentage of GTCS and mortality protection recorded. The plant's anticonvulsant mechanisms were assessed using flumazenil (5mg/kg, i.p.) before AE (100, 200, and 400mg/kg, i.p.) injection. GraphPad Prism software was used to compare the differences between various treatment groups with one-way analysis of variance (ANOVA) followed by Tukey-Krammer multiple comparison tests. RESULTS: All the plant samples except F-EtOAc significantly delayed the onset and decreased the duration of PTZ-induced MCS and GTCS, and significantly reduced the GTCS and mortality rate. Pretreatment with flumazenil diminished the significant anticonvulsant effects of AE against PTZ-induced seizures. CONCLUSIONS: It can report that extract of P. daurica ssp. macrophylla might be a helpful guide for future studies in the treatment of epilepsy.

4.
Bratisl Lek Listy ; 120(10): 752-756, 2019.
Article in English | MEDLINE | ID: mdl-31663350

ABSTRACT

AIM: Tamoxifen engages mitochondrial estrogen receptor beta as an antagonist, increases mitochondrial cytotoxicity and induces tumor cell death. Tamoxifen also engages plasma membrane estrogen receptor alpha as an agonist, while it is suggested that in some users its activation is put into action by mechanism of resistance to tamoxifen. Apoptotic inducers have been shown to promote tamoxifen-induced cell death, which might be of great importance in overcoming tamoxifen resistance. Considering the pleiotropic effects of statins, in the present study, we investigated the effects of atorvastatin on tamoxifen-induced intrinsic apoptotic pathway activity in melanoma cells. METHODS: Melanoma B16F10 cells were treated for 24 and 48 h with various concentrations of tamoxifen, atorvastatin and combination of tamoxifen + atorvastatin. Cells with no treatment were considered a control group, and the study was then followed by quantitative RT- PCR assay. Bax and cytochrome c gene expressions were calculated by ΔΔct method. RESULTS: Co-treatment of atorvastatin + tamoxifen could strongly enhance the expression of pro/apoptotic factors of Bax and cytochrome c in melanoma cells compared to the tamoxifen and atorvastatin groups. CONCLUSION: In general, we conclude that the atorvastatin-induced increase in Bax and cytochrome c gene expression might be a permissive response to tamoxifen-induced cell death (Fig. 2, Ref. 37).


Subject(s)
Apoptosis/drug effects , Atorvastatin/pharmacology , Melanoma, Experimental , Tamoxifen/pharmacology , Animals , Cell Line, Tumor , Cytochromes c/metabolism , Drug Synergism , Mice , bcl-2-Associated X Protein/metabolism
5.
Iran J Ped Hematol Oncol ; 6(1): 1-8, 2016.
Article in English | MEDLINE | ID: mdl-27222696

ABSTRACT

BACKGROUND: Peripheral blood vessels, due to availability are used for many years in cancer patients, however in patients with potentially harmful drugs to skin (vesicant drugs) or difficult accessibility to vessels, the use of implantable port (totally implantable venous access port-TIVAP) devices with central vascular access are important. MATERIALS AND METHODS: In this retrospective study, 85 pediatric cancer patients younger than 16 years, with TIVAP implantation, were followed for their complications and outcome. In addition to demographic data, patients' port complications were assessed and compared with published articles. RESULTS: Mean days of implanted port usage were 531 ± 358 days in all patients. This period was 287 ±194 days in complicated patients. Complications included as infection (tunnel infection and catheter related blood-stream infection), malfunction and thrombosis, skin erosion, tube avulsion, and tube adhesion to the adjacent vessels were seen in 30.6% of patients. CONCLUSION: According to the published data and this experience, the most common complications in TIVAP are infection and catheter malfunction. It is important to notice that in order to prolong its efficacious life, effective sterilization methods, prevention of clot formation and trauma, are the most useful measures.

6.
Int J Immunogenet ; 43(3): 131-4, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27091308

ABSTRACT

Multiple sclerosis (MS) is an organ-specific autoimmune disease in central nervous system, affecting about 2.5 million people around the world. Probable involvement of two newly identified immunoregulator molecules, TIM-1 and TIM-3, has been reported in autoimmune diseases. In this study, for the first time, the association of TIM-1 5383-5397ins/del and TIM-3 -1541C>T polymorphisms with MS in an Iranian population was considered. The results of our study showed that there is no significant association between TIM-1 5383-5397ins/del and MS (P = 0.38); however, the frequency of CT genotype of TIM-3 -1541C>T in patient group was significantly higher than the control group, and there was a significant association between CT genotype and MS (P = 0.009, OR = 4.08).


Subject(s)
Genetic Association Studies , Hepatitis A Virus Cellular Receptor 1/genetics , Hepatitis A Virus Cellular Receptor 2/genetics , Multiple Sclerosis/genetics , Adult , Female , Genetic Predisposition to Disease , Genotype , Humans , INDEL Mutation , Iran , Male , Multiple Sclerosis/pathology , Polymorphism, Single Nucleotide
7.
Lab Anim ; 50(1): 15-20, 2016 Feb.
Article in English | MEDLINE | ID: mdl-25732574

ABSTRACT

Chemotherapy-induced neuropathic pain is one of the major problems for cancer patients. Although paclitaxel and cisplatin are widely used in women, most laboratory studies of chemotherapy-induced neuropathic pain have been conducted on male animals. The current study examined the gender differences in chemotherapy-induced neuropathic pain in mice. Neuropathic pain was induced by intraperitoneal injection of paclitaxel (2 mg/kg) for five consecutive days and cisplatin (1 mg/kg) for seven consecutive days. Cold allodynia was evaluated by measuring the paw withdrawal frequency and duration of paw licking in mice; however, mechanical allodynia was assessed by von Frey filaments. Neuropathic pain began to manifest after a few days (P < 0.001). Cold allodynia was more robust in female mice (P < 0.001) treated with paclitaxel, while no differences were observed between the two genders in the manifestation of paclitaxel-induced mechanical allodynia. Interestingly, no gender differences were observed in cisplatin-induced cold and mechanical allodynia tests. In conclusion, gender differences play a major role in neuropathic pain induced by paclitaxel. The differences between male and female animals should be considered in future studies and the findings should be generalized to humans with caution.


Subject(s)
Antineoplastic Agents/adverse effects , Cisplatin/adverse effects , Neuralgia/chemically induced , Paclitaxel/adverse effects , Animals , Antineoplastic Agents, Phytogenic/adverse effects , Disease Models, Animal , Female , Injections, Intraperitoneal , Male , Mice , Sex Factors
8.
Pflugers Arch ; 466(2): 237-51, 2014 Feb.
Article in English | MEDLINE | ID: mdl-23873354

ABSTRACT

The water channels, aquaporins (AQPs) are key mediators of transcellular fluid transport. However, their expression and role in cardiac tissue is poorly characterized. Particularly, AQP1 was suggested to transport other molecules (nitric oxide (NO), hydrogen peroxide (H2O2)) with potential major bearing on cardiovascular physiology. We therefore examined the expression of all AQPs and the phenotype of AQP1 knockout mice (vs. wild-type littermates) under implanted telemetry in vivo, as well as endothelium-dependent relaxation in isolated aortas and resistance vessels ex vivo. Four aquaporins were expressed in wild-type heart tissue (AQP1, AQP7, AQP4, AQP8) and two aquaporins in aortic and mesenteric vessels (AQP1-AQP7). AQP1 was expressed in endothelial as well as cardiac and vascular muscle cells and co-segregated with caveolin-1. AQP1 knockout (KO) mice exhibited a prominent microcardia and decreased myocyte transverse dimensions despite no change in capillary density. Both male and female AQP1 KO mice had lower mean BP, which was not attributable to altered water balance or autonomic dysfunction (from baroreflex and frequency analysis of BP and HR variability). NO-dependent BP variability was unperturbed. Accordingly, endothelium-derived hyperpolarizing factor (EDH(F)) or NO-dependent relaxation were unchanged in aorta or resistance vessels ex vivo. However, AQP1 KO mesenteric vessels exhibited an increase in endothelial prostanoids-dependent relaxation, together with increased expression of COX-2. This enhanced relaxation was abrogated by COX inhibition. We conclude that AQP1 does not regulate the endothelial EDH or NO-dependent relaxation ex vivo or in vivo, but its deletion decreases baseline BP together with increased prostanoids-dependent relaxation in resistance vessels. Strikingly, this was associated with microcardia, unrelated to perturbed angiogenesis. This may raise interest for new inhibitors of AQP1 and their use to treat hypertrophic cardiac remodeling.


Subject(s)
Aquaporin 1/deficiency , Blood Pressure/physiology , Animals , Aquaporin 1/physiology , Biological Factors/physiology , Female , Heart Defects, Congenital/pathology , Hypotension/physiopathology , Male , Mice , Mice, Knockout , Myocardial Contraction/physiology , Nitric Oxide/physiology
9.
Iran J Ped Hematol Oncol ; 4(4): 167-71, 2014.
Article in English | MEDLINE | ID: mdl-25598957

ABSTRACT

BACKGROUND: Recent studies suggest an association between H. pylori infection and disorders such as iron deficiency anemia and growth delay. Considering the high prevalence of H. pylori infection and iron deficiency anemia, this study was performed in order to evaluate their relevance in children undergoing an upper endoscopy. MATERIALS AND METHODS: In this case-control study, children aged 2 to 16 years old, undergoing endoscopy from March 2012 to March 2013 at Besat Hospital of Hamedan, were selected. Participants were divided in H.Pylori infected and non-infected groups. Then the two groups were compared in terms of body mass index (BMI) and the incidence of iron deficiency anemia. The presence of Helicobacter pylori infection in children was confirmed by Giemsa staining of gastric biopsy specimens. Collected data was analyzed by SPSS 17.0 (SPSS Inc., Chicago, IL) and t-test and chi-square. RESULTS: In this study, 200 children (94 male and 106 female) were evaluated. The most common presenting symptom in both groups was abdominal pain. 8.2 % (9 cases) of the infected patients and 10.5% (10 cases) of the non-infected patients had iron deficiency anemia which this difference was not statistically significant (p=270). Also, no statistically significant difference was noted between the two groups in terms of gender (p=0.32), hemoglobin (p=0.35), Ferritin levels (p= 0.275) and body mass index (p= 0.273). CONCLUSION: The results of this study not showed an association between H. pylori infection and iron deficiency anemia or body mass index in studied children.

10.
J Nat Med ; 66(3): 447-52, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22086673

ABSTRACT

Alkanna species are used in Iranian traditional medicine for treatment of rheumatoid arthritis and other inflammatory diseases. This study was designed to evaluate the anti-inflammatory and anti-nociceptive effects of Alkanna frigida and Alkanna orientalis ethanolic extracts via the carrageenan-induced paw edema test and formalin test in rat and mouse, respectively. Ethanolic extracts of plant root were prepared and were injected intraperitoneally 60 min before carrageenan-induced inflammation or formalin-induced nociception at 100, 200 and 400 mg/kg. Anti-inflammatory effects of plants were monitored for 3 h after carrageenan injection and anti-nociceptive effects were evaluated during the first hour after formalin injection. Diclofenac, a well-known anti-inflammatory and anti-nociceptive agent, was used as a positive control. Our results show that, in contrast to Alkanna orientalis, ethanolic extract of Alkanna frigida significantly decreases carrageenan-induced inflammation at 400 mg/kg, especially 3 h after inflammation induction. Both Alkanna frigida and Alkanna orientalis ethanolic extracts possess a remarkable anti-nociceptive effect at each dose (100, 200 and 400 mg/kg) in a dose-dependent manner during the first hour after formalin injection.The present findings provide more evidence for the potential anti-nociceptive effect of Alkanna sp. and the anti-inflammatory effect of Alkanna frigida. It supports their traditional indication in the treatment of pain and inflammatory-related diseases. These useful effects may result from the inhibitory interaction of the plant ethanolic extract with cyclooxygenase-2 enzyme and the subsequent reduction in prostaglandin production.


Subject(s)
Analgesics/therapeutic use , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/therapeutic use , Boraginaceae/chemistry , Ethanol/chemistry , Plant Extracts/chemistry , Plant Extracts/therapeutic use , Analgesics/chemistry , Animals , Carrageenan/toxicity , Female , Male , Mice , Pain/chemically induced , Pain/drug therapy , Rats
11.
Indian J Med Microbiol ; 28(3): 233-7, 2010.
Article in English | MEDLINE | ID: mdl-20644312

ABSTRACT

PURPOSE: To investigate the difference between the abilities of Helicobacter pylori and Escherichia coli to induce expression of TNF-alpha in human peripheral blood mononuclear cells (PBMC). MATERIALS AND METHODS: H pylori was isolated from gastric biopsy specimens. The mononuclear cells were isolated from human blood, cultured, and treated with either intact or sonicated E coli or H pylori, and mRNA expression for TNF-alpha was detected using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: TNF-alpha mRNA expression levels were significantly higher in PBMCs stimulated with E coli compared to those stimulated with H pylori at the same number and identical conditions (P < .001). The results also suggest that sonicated bacteria were significantly (P < .001) less stimulatory for PBMCs than intact bacteria for both E coli and H pylori. CONCLUSIONS: The ability of different H pylori strains isolated from biopsy samples to stimulate TNF-alpha from PBMCs was significantly lower than that of E coli. Sonicated bacteria, as compared to intact bacteria, was a very poor inducer of TNF-alpha mRNA expression, suggesting that the conformation of lipopolysaccharides (LPS) on the outer leaflet of the outer membrane is not totally conserved in sonicated bacteria.


Subject(s)
Escherichia coli/immunology , Helicobacter pylori/immunology , Leukocytes, Mononuclear/immunology , Tumor Necrosis Factor-alpha/biosynthesis , Adult , Cells, Cultured , Gene Expression Profiling , Humans , RNA, Bacterial/biosynthesis , RNA, Messenger/biosynthesis , Reverse Transcriptase Polymerase Chain Reaction
12.
Phytother Res ; 23(6): 797-800, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19172582

ABSTRACT

The enhancement of the antibacterial activity of ampicillin by different extracts of Berberis integerrima fruits was evaluated against Staphylococcus aureus. Disk diffusion and agar dilution methods were used to determine the antibacterial activity of ampicillin in the absence and presence of different plant extracts or various fractions eluted by column chromatography. A clinical isolate of S. aureus was used as a test strain. The active component of B. integerrima fruits involved in the enhancement of ampicillin activity was purified and identified as 1-methyl malate using different spectroscopic methods. Both the ethanol extract of B. integerrima fruits and 1-methyl malate enhanced the antibacterial activity of ampicillin. The total extract as well as 1-methyl malate increased the antibacterial activity of ampicillin against the test strain. The potency of ampicillin against the test strain was increased 64-fold when tested with a sub-toxic concentration of total extract of B. integerrima fruits. Also, 1-methyl malate increased the bactericidal activity of ampicillin. In the presence of 2 mg/mL of 1-methyl malate the MIC of ampicillin for S. aureus decreased from 128 to 1 microg/mL (128-fold).


Subject(s)
Ampicillin/pharmacology , Anti-Bacterial Agents/pharmacology , Malates/pharmacology , Plant Extracts/pharmacology , Staphylococcus aureus/drug effects , Berberis/chemistry , Drug Synergism , Fruit/chemistry , Microbial Sensitivity Tests , Molecular Structure
13.
J Food Sci ; 72(1): S055-8, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17995898

ABSTRACT

Therapy with antimicrobial drugs, such as clindamycin, that perturb the intestinal flora but fail to inhibit growth of other microorganisms can permit the proliferation of Clostridium difficile and the elaboration of exotoxin. Therefore, there has been increasing interest in the use of inhibitors of antibiotic resistance for use in combination therapy. The essential oil of Cinnamomum zeylanicum bark enhanced the bactericidal activity of clindamycin and decreased the minimum inhibitory concentration of clindamycin required for a toxicogenic strain of C. difficile. Thin-layer chromatography (TLC) analysis of the essential oil separated a fraction (R(f) = 0.54) that was the most effective at enhancing the clindamycin antimicrobial activity. Using gas liquid chromatography and known standards, the active fraction was identified as trans-cinnamaldehyde (3-phenyl-2-Propenal). Combinations of clindamycin and trans-cinnamaldehyde were tested to determine the fractional inhibitory concentration (FIC) index by conventional checkerboard titration. The FIC index for C. difficile was found to be 0.312, which confirmed the synergistic actions of clindamycin and trans-cinnamaldehyde. The presence of 20 microg/mL of trans-cinnamaldehyde decreased the MIC of clindamycin for C. difficile 16-fold, from 4.0 to 0.25 microg/mL. These results signify that low concentrations of trans-cinnamaldehyde elevate the antimicrobial action of clindamycin, suggesting a possible clinical benefit for utilizing these natural products for combination therapy against C. difficile.


Subject(s)
Acrolein/analogs & derivatives , Anti-Bacterial Agents/pharmacology , Cinnamomum zeylanicum/chemistry , Clindamycin/pharmacology , Clostridioides difficile/drug effects , Drug Resistance, Bacterial/drug effects , Acrolein/analysis , Acrolein/pharmacology , Anti-Bacterial Agents/analysis , Chromatography, Thin Layer , Clostridioides difficile/growth & development , Colony Count, Microbial , Dose-Response Relationship, Drug , Drug Synergism , Microbial Sensitivity Tests , Oils, Volatile/chemistry
14.
J Endocrinol ; 188(2): 251-61, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16461551

ABSTRACT

Growth hormone insensitivity syndrome (GHIS) has been reported in a family homozygous for a point mutation in the GH receptor (GHR) that activates an intronic pseudoexon. The resultant GHR (GHR1-656) includes a 36 amino-acids insertion after residue 207, in the region known to be important for homodimerization of GHR. We have examined the functional consequences of such an insertion in mammalian cells transfected with the wild type (GHRwt) and mutated GHR (GHR1-656). Radio-ligand binding and flow cytometry analysis showed that GHR1-656 is poorly expressed at the cell surface compared with GHRwt. Total membrane binding and Western blot analysis showed no such difference in the level of total cellular GHR expressed for GHR1-656 vs GHRwt. Immunofluorescence showed GHR1-656 to have different cellular distribution to the wild type receptor (GHRwt), with the mutated GHR being mainly perinuclear and less vesicular than GHRwt. Western blot analysis showed GH-induced phosphorylation of Jak2 and Stat5 for both GHR1-656 and GHRwt, although reduced Stat5 activity was detected with GHR1-656, consistent with lower levels of expression of GHR1-656 than GHRwt at the cell surface. In conclusion, we report that GHIS, due to a 36 amino-acids insertion in the extracellular domain of GHR, is likely to be explained by a trafficking defect rather than by a signalling defect of GHR.


Subject(s)
Laron Syndrome/genetics , Receptors, Somatotropin/genetics , Amino Acids/genetics , Blotting, Western , Cell Membrane , Cells, Cultured , Flow Cytometry/methods , Fluorescent Antibody Technique/methods , Gene Expression Regulation/genetics , Homozygote , Humans , Janus Kinase 2 , Luciferases/genetics , Male , Phosphorylation , Point Mutation/genetics , Protein-Tyrosine Kinases/genetics , Proto-Oncogene Proteins/genetics , STAT5 Transcription Factor/genetics , Signal Transduction/genetics , Transfection
15.
J Immunol ; 167(8): 4593-9, 2001 Oct 15.
Article in English | MEDLINE | ID: mdl-11591788

ABSTRACT

Leptin is capable of modulating the immune response. Proinflammatory cytokines induce leptin production, and we now demonstrate that leptin can directly activate the inflammatory response. RNA expression for the leptin receptor (Ob-R) was detectable in human PBMCs. Ob-R expression was examined at the protein level by whole blood flow cytometry using an anti-human Ob-R mAb 9F8. The percentage of cells expressing leptin receptor was 25 +/- 5% for monocytes, 12 +/- 4% for neutrophils, and 5 +/- 1% for lymphocytes (only B lymphocytes). Incubation of resting PBMCs with leptin induced rapid expression of TNF-alpha and IL-6 mRNA and a dose-dependent production of TNF-alpha and IL-6 by monocytes. Incubation of resting PBMCs with high-dose leptin (250 ng/ml, 3-5 days) induced proliferation of resting cultured PBMCs and their secretion of TNF-alpha (5-fold), IL-6 (19-fold), and IFN-gamma (2.5-fold), but had no effect on IL-4 secretion. The effect of leptin was distinct from, and additive to, that seen after exposure to endotoxin or activation by the mixed lymphocyte reaction. In conclusion, Ob-R is expressed on human circulating leukocytes, predominantly on monocytes. At high doses, leptin induces proinflammatory cytokine production by resting human PBMCs and augments the release of these cytokines from activated PBMCs in a pattern compatible with the induction of Th1 cytokines. These results demonstrate that leptin has a direct effect on the generation of an inflammatory response. This is of relevance when considering leptin therapy and may partly explain the relationship among leptin, proinflammatory cytokines, insulin resistance, and obesity.


Subject(s)
Carrier Proteins/metabolism , Leptin/pharmacology , Leukocytes, Mononuclear/immunology , Monocytes/metabolism , Receptors, Cell Surface , Receptors, Cytokine/metabolism , Adult , Antibodies, Monoclonal , Carrier Proteins/immunology , Carrier Proteins/isolation & purification , Cell Division , Cells, Cultured , Endotoxins/pharmacology , Humans , Interferon-gamma/metabolism , Interleukin-4/metabolism , Interleukin-6/metabolism , Lymphocyte Culture Test, Mixed , Middle Aged , Receptors, Leptin , Tumor Necrosis Factor-alpha/metabolism
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