TRANSFERRIN RESEARCH

noreply@blogger.com (Unknown) — Mon, 20 Sep 2010 20:46:00 +0000

Abstract
Transferrin is an essential ingredient used in cell culture media due to its crucial role in regulating cellular iron uptake, transport, and utilization. It is also a promising drug carrier used to increase a drug’s therapeutic index via the unique transferrin receptor-mediated endocytosis pathway. Due to the high risk of contamination with blood–borne pathogens from the use of human or animal plasma-derived transferrin, recombinant transferrin is preferred for use as a replacement for native transferrin.

We expressed recombinant human transferrin in rice (Oryza sativa L.) at a high level of 1% seed dry weight (10 g/kg). The recombinant human transferrin was able to be extracted with saline buffers and then purified by a one step anion exchange chromatographic process to greater than 95% purity. The rice-derived recombinant human transferrin was shown to be not only structurally similar to the native human transferrin, but also functionally the same as native transferrin in terms of reversible iron binding and promoting cell growth and productivity.

These results indicate that rice-derived recombinant human transferrin should be a safe and low cost alternative to human or animal plasma-derived transferrin for use in cell culture-based biopharmaceutical production of protein therapeutics and vaccines

Deshui Zhanga, , , Somen Nandia, 1, Paula Bryana, 2, Steve Pettitb, Diane Nguyena, Mary Ann Santosb and Ning Huanga, b,

Protein Expression and Purification
Volume 74, Issue 1, November 2010, Pages 69-79

Transferrin as a Luminal Target for Negatively Charged Liposomes in the Inflamed Colonic Mucosa

noreply@blogger.com (Unknown) — Wed, 19 Aug 2009 19:48:00 +0000

The need for improved specificity in the local treatment of inflammatory bowel diseases (IBD) led us to use negatively charged liposomes to target the inflamed colonic epithelium. The purpose of the present study was to elucidate the cause for our previous observations that such liposomes accumulate, preferentially, in the inflamed mucosa of rats that were induced with experimental colitis, following luminal administration. Protein analysis (tandem mass spectrometry, verified by Western blot) of inflamed mucosal specimens, extracted at pH 3, 5 and 7, revealed an increased expression of transferrin (TF) at pH 3. Histological examination indicated that the TF was located at the luminal side of the inflamed epithelium. Negatively charged (but not neutral) liposomes adhered to both commercial and mucosal TF at low pH, but not at neutral pH. Moreover, preincubation of negatively charged liposomes with TF profoundly attenuated their adherence to the inflamed mucosa of the rat colon. It is concluded that, at a low pH, typical of the colon lumen in ulcerative colitis, TF mediates specific mucoadhesion of negatively charged liposomes to the inflamed mucosa. This observation could be useful in the rational design of specific drug vehicles aimed at IBD therapy after luminal administration.

Tirosh B, Khatib N, Barenholz Y, Nissan A, Rubinstein A.
Department of Pharmacology and Experimental Therapeutics, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, P.O. Box 12065, Jerusalem 91120, Israel, Department of Pharmaceutics, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, P.O. Box 12065, Jerusalem 91120, Israel, Laboratory of Membrane and Liposome Research, The Hebrew University-Hadassah Medical School, Jerusalem, Israel, and Department of Surgery, Hadassah-Hebrew University Medical Center, Mount Scopus, P.O. Box 24035, Jerusalem 91240, Israel

Transferrin and ferritin response to bacterial infection: the role of the liver and brain in fish

noreply@blogger.com (Unknown) — Tue, 30 Jun 2009 18:28:00 +0000

Iron is essential for growth and survival, but it is also toxic when in excess. Thus, there is a tight regulation of iron that is accomplished by the interaction of several genes including the iron transporter transferrin and iron storage protein ferritin. These genes are also known to be involved in response to infection. The aim of this study was to understand the role of transferrin and ferritin in infection and iron metabolism in fish. Thus, sea bass transferrin and ferritin H cDNAs were isolated from liver, cloned and characterized. Transferrin constitutive expression was found to be highest in the liver, but also with significant expression in the brain, particularly in the highly vascularized region connecting the inferior lobe of the hypothalamus and the saccus vasculosus. Ferritin, on the other hand, was expressed in all tested organs, but also significantly higher in the liver. Fish were subjected to either experimental bacterial infection or iron modulation and transferrin and ferritin mRNA expression levels were analyzed, along with several iron regulatory parameters. Transferrin expression was found to decrease in the liver and increase in the brain in response to infection and to increase in the liver in iron deficiency. Ferritin expression was found to inversely reflect transferrin in the liver, increasing in infection and iron overload and decreasing in iron deficiency, whereas in the brain, ferritin expression was also increased in infection. These findings demonstrate the evolutionary conservation of transferrin and ferritin dual functions in vertebrates, being involved in both the immune response and iron metabolism.

Neves JV, Wilson JM, Rodrigues PN.
IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal

Ceruloplasmin/Transferrin System Is Related to Clinical Status in Acute Stroke

noreply@blogger.com (Unknown) — Thu, 14 May 2009 01:26:00 +0000

Background and Purpose— In acute stroke, Iron (Fe) may amplify reperfusion injury by catalyzing the conversion of superoxide and hydrogen peroxide into highly reactive radicals. Transferrin (Tf) is the main protein regulating Fe homeostasis, whereas Ceruplasmin (CP) is a circulating ferroxidase enzyme able to oxidize ferrous ions to less toxic ferric forms. This study aims at investigating whether CP, Copper (Cu), Tf, and Fe play a role in the pathophysiology of acute stroke.

Methods— We enrolled 35 acute stroke patients and 44 controls. All patients underwent: neurological examination assessed by National Institutes of Health Stroke Scale (NIHSS), ultrasound evaluation of carotid atherosclerosis, brain MRI to quantify ischemic lesion volume and measurement of serum levels of CP, Cu, Tf, Fe, hydro-peroxides, and Total plasmatic antioxidant capacity.

Results— In patients, NIHSS scores were associated with Tf (r=–0.48, P=0.004), hydro-peroxides (r=0.34, P=0.046), CP (r=0.43, P=0.012), and lesion volume (r=0.50, P=0.004). Lesion volume was inversely associated with Tf (r=–0.44, P=0.012). CP and hydro-peroxides were also largely related (r=0.81, P<0.001). The model multiple R was 0.57, resulting in a 32.5% of explained NIHSS variance with Tf accounting for 23.4% and CP for 9.1%.

Conclusions— CP and Tf levels are representative of clinical status in acute stroke patients. Our findings suggest a protective role of Tf in acute stroke and a possible ambivalent role of CP.

The Usefulness of the Serum Transferrin Receptor to Serum Ferritin Ratio for Discriminating between Iron Deficiency Anemia and Anemia of Inflammation

noreply@blogger.com (Unknown) — Fri, 08 Aug 2008 15:08:00 +0000

BACKGROUND: The incidence of iron deficiency anaemia in infants, which is caused by the increased iron demand for rapid growth during this period, is reported to range from 10 to 40%. This age group also suffers from a number of acute illnesses (urinary tract infection, pneumonia and other viral illness). The aim of this study was to evaluate the usefulness of soluble transferrin receptor (sTfR) values and the different methods of calculating the sTfR and serum ferritin (SF) ratio for differentiating anemia of inflammation (AI) from iron deficiency anemia (IDA) or a mixture of these two types of anemia.

METHODS: 173 infants among all the infants who visited Gyeongsang National University Hospital from 2000 to 2006 were enrolled in this study. The hemoglobin (Hb), SF and sTfR values were checked and the infants were divided into the Al subgroup (Hb <11g/dL and SF > 50microgram/L), the IDA subgroup (Hb <11g/dL and SF < 12microgram/L), the normal group (Hb > or =11g/dL and SF > or =12microgram/L), and the unclassified anemia (UCA) group (Hb <11g/dL and SF 12~50microgram/L).

RESULTS: The mean sTfR and sTfR/Log SF values in the AI group were 3.89 and 10.6microgram/mL, respectively (P<0.01). These values in the IDA group were 1.9 and 36.11, respectively (P<0.01). The mean Log (sTfR/SF) was statistically significant between all the subgroups (1.35 in AI, 3.29 in IDA, 1.76 in Nor and 2.35 in UCA). All the infants in the IDA group had a Log (sTfR/SF) value >2.55 whereas all the infants classified in AI group had a Log (sTfR/SF) value <2.55.

CONCLUSION: The Log (sTfR/SF) value is a useful criterion for discriminating between AI and IDA.

The Usefulness of the Serum Transferrin Receptor to Serum Ferritin Ratio for Discriminating between Iron Deficiency Anemia and Anemin of Inflamation

noreply@blogger.com (Unknown) — Thu, 24 Jul 2008 19:18:00 +0000

BACKGROUND:
The incidence of iron deficiency anaemia in infants, which is caused by the increased iron demand for rapid growth during this period, is reported to range from 10 to 40%. This age group also suffers from a number of acute illnesses (urinary tract infection, pneumonia and other viral illness). The aim of this study was to evaluate the usefulness of soluble transferrin receptor (sTfR) values and the different methods of calculating the sTfR and serum ferritin (SF) ratio for differentiating anemia of inflammation (AI) from iron deficiency anemia (IDA) or a mixture of these two types of anemia.

METHODS:
173 infants among all the infants who visited Gyeongsang National University Hospital from 2000 to 2006 were enrolled in this study. The hemoglobin (Hb), SF and sTfR values were checked and the infants were divided into the Al subgroup (Hb <11g/dL and SF > 50microgram/L), the IDA subgroup (Hb <11g/dL and SF < 12microgram/L), the normal group (Hb > or =11g/dL and SF > or =12microgram/L), and the unclassified anemia (UCA) group (Hb <11g/dL and SF 12~50microgram/L).

RESULTS:
The mean sTfR and sTfR/Log SF values in the AI group were 3.89 and 10.6 microgram/mL, respectively (P<0.01). These values in the IDA group were 1.9 and 36.11, respectively (P<0.01). The mean Log (sTfR/SF) was statistically significant between all the subgroups (1.35 in AI, 3.29 in IDA, 1.76 in Nor and 2.35 in UCA). All the infants in the IDA group had a Log (sTfR/SF) value >2.55 whereas all the infants classified in AI group had a Log (sTfR/SF) value <2.55.

CONCLUSION:
The Log (sTfR/SF) value is a useful criterion for discriminating between AI and IDA.

Taking iron measures - Human Transferrin

noreply@blogger.com (Unknown) — Tue, 05 Feb 2008 20:17:00 +0000

A more accurate method to measure iron in clinical samples is proving ahead of its time, say researchers in Spain.

The group at the University of Oviedo in Spain, led by Alfredo Sanz-Medel, has developed a technique that allows many variables that can indicate iron-related disease to be measured simultaneously and with great precision.

"Iron is used in numerous enzymes and processes throughout the human body"Any imbalance in the amount of iron in the body can lead to disease, said Sanz-Medel. But many different parameters need to be measured to detect such pathologies - since the metal is used not just as an oxygen transporter in the blood but also in numerous enzymes and processes throughout the human body. Until now these parameters have had to be measured separately, often needing multiple steps.

Sanz-Medel's method avoids this and uses transferrin (Tf), a blood plasma protein that transports iron around the body, to measure iron levels in serum. The group saturate the transferrin with either naturally-occurring iron or a non-radioactive isotope and use high performance liquid chromatography (HPLC) and inductively coupled plasma-mass spectrometry (ICP-MS) techniques to measure the amounts of the metal and protein. By comparing the iron isotope ratios, the data can be used to extrapolate clinically useful parameters including the amount of iron bound to tranferrin (Tf) and unbound in serum.

Ferritin and Transferrin Are Associated With Metabolic Syndrome Abnormalities

noreply@blogger.com (Unknown) — Fri, 14 Dec 2007 22:33:00 +0000

OBJECTIVE—The aim of this work was to study cross-sectional and longitudinal relations between iron stocks ( Ferritin ) and the iron transport protein ( transferrin ) with the metabolic syndrome and its abnormalities.

RESEARCH DESIGN AND METHODS—A total of 469 men and 278 premenopausal and 197 postmenopausal women from the French Data from an Epidemiological Study on the Insulin Resistance Syndrome (DESIR) cohort, aged 30–65 years, were followed over 6 years.

RESULTS—Higher concentrations of both ferritin and transferrin were associated with the International Diabetes Federation (IDF) and the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults Adult Treatment Panel III original and revised definitions of the metabolic syndrome at baseline: for the IDF definition of the metabolic syndrome , the standardized, age-adjusted odds ratios (95% CI) for log(ferritin) were 1.49 (1.14–1.94) for men, 2.10 (1.27–3.48) for premenopausal women , and 1.80 (1.21–2.68) for postmenopausal women; for transferrin they were, respectively, 1.94 (1.53–2.47), 2.22 (1.32–3.75), and 2.14 (1.47–3.10). After 6 years of follow-up, the change in the presence of the metabolic syndrome was associated with higher baseline values in all three groups: log(ferritin), 1.46 (1.13–1.89), 1.28 (0.85–1.94), and 1.62 (1.10–2.38); and transferrin, 1.41 (1.10–1.81), 1.63 (1.05–2.52), and 1.51 (1.02–2.22). Among syndrome components, hypertriglyceridemia at 6 years was the component most strongly associated with baseline ferritin and transferrin . The odds of an incident IDF-defined metabolic syndrome after 6 years was more than fourfold higher when ferritin and transferrin values were both above the group-specific top tertile, in comparison with participants with both parameters below these thresholds.

CONCLUSIONS—This is the first prospective study associating ferritin and transferrin with the metabolic syndrome and its components. When both markers of the iron metabolism are elevated, the incidence of the metabolic syndrome is increased in men and both pre- and postmenopausal women.

Diabetes Care 30:1795-1801, 2007
DOI: 10.2337/dc06-2312
Beverley Balkau , INSERM U780, Villejuif 94807, France

Bivariate mixture modeling of transferrin saturation

noreply@blogger.com (Unknown) — Fri, 23 Nov 2007 18:36:00 +0000

Bivariate mixture modeling was used to analyze joint population distributions of transferrin saturation (TS) and serum Ferritin concentration (SF) measured in the Hemochromatosis and Iron Overload Screening (HEIRS) Study.

Four components (C1, C2, C3, and C4) with successively age-adjusted increasing means for transferrin saturation and serum ferritin were identified in data from 26,832 African Americans, 12,620 Asians, 12,264 Hispanics, and 43,254 whites. The largest component, C2, had normal mean transferrin saturation Transferrin (21% to 26% for women, 29% to 30% for men) and Serum ferritin (43–82 μg/L for women, 165–242 μg/L for men), which consisted of component proportions greater than 0.59 for women and greater than 0.68 for men. C3 and C4 had progressively greater mean values for transferrin saturation and serum ferritin with progressively lesser component proportions.

C1 had mean Transferrin Saturation values less than 16% for women (<20% for men) and SF values less than 28 μg/L for women (<47 μg/L for men). Compared with C2, adjusted odds of iron deficiency were significantly greater in C1 (14.9–47.5 for women, 60.6–3530 for men), adjusted odds of liver disease were significantly greater in C3 and C4 for African-American women and all men, and adjusted odds of any HFE mutation were increased in C3 (1.4–1.8 for women, 1.2–1.9 for men) and in C4 for Hispanic and white women (1.5 and 5.2, respectively) and men (2.8 and 4.7, respectively). Joint mixture modeling identifies a component with lesser serum ferritin and transferrin saturation at risk for iron deficiency and 2 components with greater SF and TS at risk for liver disease or HFE mutations . This approach can identify populations in which hereditary or acquired factors influence metabolism measurement.

Abbreviations: EM, expectation-maximization; HFE, hemochromatosis gene on chromosome 6p; HEIRS, Hemochromatosis and Iron Overload Screening; SF, serum ferritin concentration; TS, transferrin saturation; wt, wild type

The HEIRS Study was initiated and funded by NHLBI in conjunction with NHGRI. Supported by contracts N01-HC-05185 ( University of Minnesota), N01-HC-05186 (Howard University ), N01-HC-05188 (University of Alabama at Birmingham), N01-HC-05189 (Kaiser Permanente Center for Health Research), N01-HC-05190 (University of California, Irvine), N01-HC-05191 (London Health Sciences Centre), and N01-HC-05192 (Wake Forest University). Also supported by Grant R01 HL083328-01A1 from the National Heart, Lung, and Blood Institute (to C.E.M.); Grant M01-RR00032 from the University of Alabama at Birmingham General Clinical Research Center (GCRC); the Southern Iron Disorders Center (to J.C.B.); Grant M01-RR10284 from Howard University GCRC; Howard University Research Scientist Award UH1-HL03679-05 from the National Heart, Lung, and Blood Institute and the Office of Research on Minority Health (to V.R.G.); and Grant UC Irvine M01RR 00827-29 from the General Clinical Research Centers Program of the National Center for Research Resources National Institutes of Health.

What is Human Transferrin

noreply@blogger.com (Unknown) — Fri, 19 Oct 2007 16:12:00 +0000

Human Transferrin is a plasma protein for iron ion delivery. Human Transferrin is a glycoprotein with homologous N-terminal and C-terminal iron binding domains. Transferrin(TF) is related to other iron binding proteins including lactoferrin . When human transferrin loaded with iron encounters a transferrin receptor on the surface of a cell, it binds to it and is consequently transported into the cell in a vesicle. The cell will acidify the vesicle, causing human transferrin(TF) to release its iron ions. Each human transferrin molecule has the ability to carry two iron ions in the ferric form (Fe3+). Commercially purified Human Apo Transferrin and human Holo Transferrin available from diagnostic raw material manufacturers such as Lee Biosolutions, Inc .

The Cytoplasmic Domain of Transferrin Receptor 2 Dictates Its Stability and Response to Holo-transferrin in Hep3B Cells

noreply@blogger.com (Unknown) — Fri, 19 Oct 2007 16:00:00 +0000

Transferrin receptor 2 (TfR2) is a homolog of transferrin receptor 1 (TfR1), the receptor responsible for the uptake of iron-loaded transferrin (holo-Tf) into cells.The half-life of the chimera increased 2.7-fold in cells exposed to Human Holo Transferrin holo-Tf like the endogenous TfR2 in HepG2 cells. Like TfR2 and unlike TfR1, the levels of the chimera did not respond to intracellular iron content. These results suggest that although holo-Tf binding to the ectodomain is necessary, the cytoplasmic domain of TfR2 is largely responsible for its stabilization by holo-Tf .