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

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

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

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.