Cloning and characterization of the human lactoferrin receptor gene promoter

Lactoferrin/lactoferrin receptor: Neurodegenerative or neuroprotective in Parkinson's disease?

Lactoferrin (Lf) is a multifunctional protein in the transferrin family. It is involved in many physiological functions, including the regulation of iron absorption and immune response. It also has antibacterial, antiviral, anti-inflammatory, anticancer and antioxidant capabilities under pathophysiological conditions. The mammalian lactoferrin receptor (LfR) plays a key role in mediating multiple functions of Lf. Studies have shown that Lf/LfR is abnormally expressed in the brain of Parkinson's disease, and the excessive accumulation of iron in the brain caused by the overexpression of Lf and LfR is considered to be one of the initial causes of the degeneration of dopaminergic neurons in Parkinson's disease. On the other hand, a number of recent studies have reported that Lf/LfR has a significant neuroprotective effect on Parkinson's disease. In other words, it seems paradoxical that Lf/LfR has both neurodegenerative and neuroprotective effects in Parkinson's disease. This article focuses on recent advances in the possible mechanisms of the neurodegenerative and neuroprotective effects of Lf/LfR in Parkinson's disease and discusses why Lf/LfR has a seemingly contradictory role in the development of Parkinson's disease. Based on the evidence obtained so far, we believed that Lf/LfR has a neuroprotective effect on Parkinson's disease, while as to whether the overexpressed Lf/LfR is the cause of the development of Parkinson's disease, the current evidence is insufficient and further investigation needed.

Molecular Characterization and Expression of Lactoferrin Receptor (LfR) in Different Regions of the Brain Responding to Lactoferrin Intervention

Lactoferrin (LF), an iron-binding glycoprotein rich in human milk, promotes neurodevelopment and cognition, but whether it acts through the LF receptor (LfR) and its expression profile in the brain remains unknown. We characterized 972 bp of piglet brain LfR cDNA and found LfR mRNA was expressed all brain regions being highest in the frontal lobe, followed by parietal lobe, brainstem, occipital lobe, cingulate gyrus, subventricular zone, olfactory bulb, hippocampus, amygdala, cerebellum, and thalamus. LfR mRNA and protein in different regions of the brain responded to low (155 mg/kg/day) and high (285 mg/kg/day) LF supplementation of piglets from postnatal days 3 to 38. By postnatal day 39, the low LF diet significantly increased LfR protein expression in the occipital lobe compared to controls, but not the high LF diet. LfR protein in the subventricular zone of the high LF group was 42% and 38% higher than that of the low LF group and controls, respectively. There was a trend for a dose-response relationship between LF intervention and LfR protein expression only in the prefrontal and parietal lobes. LF supplementation significantly improved piglet working memory for a difficult task, which was positively correlated with LfR protein in the prefrontal, parietal, and occipital lobes, but no dose response. Brain LfR responds to dietary LF supplementation, a mechanism by which LF can promote learning and working memory through its receptor. LfR is expressed in the whole brain, and its expression level is anatomic region specific.

Intelectin-1 binds and alters the localization of the mucus barrier-modifying bacterium Akkermansia muciniphila

Intelectin-1 (ITLN1) is a lectin secreted by intestinal epithelial cells (IECs) and upregulated in human ulcerative colitis (UC). We investigated how ITLN1 production is regulated in IECs and the biological effects of ITLN1 at the host-microbiota interface using mouse models. Our data show that ITLN1 upregulation in IECs from UC patients is a consequence of activating the unfolded protein response. Analysis of microbes coated by ITLN1 in vivo revealed a restricted subset of microorganisms, including the mucolytic bacterium Akkermansia muciniphila. Mice overexpressing intestinal ITLN1 exhibited decreased inner colonic mucus layer thickness and closer apposition of A. muciniphila to the epithelial cell surface, similar to alterations reported in UC. The changes in the inner mucus layer were microbiota and A. muciniphila dependent and associated with enhanced sensitivity to chemically induced and T cell-mediated colitis. We conclude that by determining the localization of a select group of bacteria to the mucus layer, ITLN1 modifies this critical barrier. Together, these findings may explain the impact of ITLN1 dysregulation on UC pathogenesis.

Exercise training modulates adipokine dysregulations in metabolic syndrome

Metabolic syndrome (MetS) is a cluster of risk factors for various metabolic diseases, and it is characterized by central obesity, dyslipidemia, hypertension, and insulin resistance. The core component for MetS is adipose tissue, which releases adipokines and influences physical health. Adipokines consist of pro and anti-inflammatory cytokines and contribute to various physiological functions. Generally, a sedentary lifestyle promotes fat accumulation and secretion of pro-inflammatory adipokines. However, regular exercise has been known to exert various beneficial effects on metabolic and cognitive disorders. Although the mechanisms underlying exercise beneficial effects in MetS are not fully understood, changes in energy expenditure, fat accumulation, circulatory level of myokines, and adipokines might be involved. This review article focuses on some of the selected adipokines in MetS, and their responses to exercise training considering possible mechanisms.

Lactoferrin Efficacy versus Ferrous Sulfate in Treatment of Children with Iron Deficiency Anemia

Lactoferrin (LF) is an iron-binding globular glycoprotein that is structurally and chemically similar to serum transferrin. Many studies have been done to evaluate the effect of oral LF administration on iron deficiency anemia (IDA) with controversial results. This study was designed to compare the efficacy of LF versus oral ferrous sulfate (OFS) therapy in the treatment of children with IDA. A significant increase in mean hemoglobin and serum iron concentrations was noted in the group that received oral bovine LF (11.06 ± 0.96 and 42.79 ± 6.14, respectively) versus the group that received OFS (10.24 ± 0.57 and 28.94 ± 5.05, respectively, with p < 0.001 for each) after 30 days of the treatment with fewer side effects (9.3 vs. 33.3% with p = 0.043). Oral bovine LF is a more effective and safer alternative in treating iron deficiency and IDA compared with OFS with clinical benefits of fewer side effects and better patient compliance.

Recombinant human lactoferrin carrying humanized glycosylation exhibits antileukemia selective cytotoxicity, microfilament disruption, cell cycle arrest, and apoptosis activities

Lactoferrin has gained extensive attention due to its ample biological properties. In this study, recombinant human lactoferrin carrying humanized glycosylation (rhLf-h-glycan) expressed in the yeast Pichia pastoris SuperMan5, which is genetically glycoengineered to efficiently produce functional humanized glycoproteins inclosing (Man)5(GlcNAc)2 Asn-linked glycans, was analyzed, inspecting its potential toxicity against cancer cells. The live-cell differential nuclear staining assay was used to quantify the rhLf-h-glycan cytotoxicity, which was examined in four human cell lines: acute lymphoblastic leukemia (ALL) CCRF-CEM, T-cell lymphoblastic lymphoma SUP-T1, cervical adenocarcinoma HeLa, and as control, non-cancerous Hs27 cells. The defined CC50 values of rhLf-h-glycan in CCRF-CEM, SUP-T1, HeLa, and Hs27 cells were 144.45 ± 4.44, 548.47 ± 64.41, 350 ± 14.82, and 3359.07 ± 164 µg/mL, respectively. The rhLf-h-glycan exhibited a favorable selective cytotoxicity index (SCI), preferentially killing cancer cells: 23.25 for CCRF-CEM, 9.59 for HeLa, and 6.12 for SUP-T1, as compared with Hs27 cells. Also, rhLf-h-glycan showed significant antiproliferative activity (P < 0.0001) at 24, 48, and 72 h of incubation on CCRF-CEM cells. Additionally, it was observed via fluorescent staining and confocal microscopy that rhLf-h-glycan elicited apoptosis-associated morphological changes, such as blebbing, nuclear fragmentation, chromatin condensation, and apoptotic bodies in ALL cells. Furthermore, rhLf-h-glycan-treated HeLa cells revealed shrinkage of the microfilament structures, generating a speckled/punctuated pattern and also caused PARP-1 cleavage, a hallmark of apoptosis. Moreover, in ALL cells, rhLf-h-glycan altered cell cycle progression inducing the G2/M phase arrest, and caused apoptotic DNA fragmentation. Overall, our findings revealed that rhLf-h-glycan has potential as an anticancer agent and therefore deserves further in vivo evaluation.

Brain Delivery of Nanomedicines: Trojan Horse Liposomes for Plasmid DNA Gene Therapy of the Brain

Non-viral gene therapy of the brain is enabled by the development of plasmid DNA brain delivery technology, which requires the engineering and manufacturing of nanomedicines that cross the blood-brain barrier (BBB). The development of such nanomedicines is a multi-faceted problem that requires progress at multiple levels. First, the type of nanocontainer, e.g., nanoparticle or liposome, which encapsulates the plasmid DNA, must be developed. Second, the type of molecular Trojan horse, e.g., peptide or receptor-specific monoclonal antibody (MAb), must be selected for incorporation on the surface of the nanomedicine, as this Trojan horse engages specific receptors expressed on the BBB, and the brain cell membrane, to trigger transport of the nanomedicine from blood into brain cells beyond the BBB. Third, the plasmid DNA must be engineered without bacterial elements, such as antibiotic resistance genes, to enable administration to humans; the plasmid DNA must also be engineered with tissue-specific gene promoters upstream of the therapeutic gene, to insure gene expression in the target organ with minimal off-target expression. Fourth, upstream manufacturing of the nanomedicine must be developed and scalable so as to meet market demand for the target disease, e.g., annual long-term treatment of 1,000 patients with an orphan disease, short term treatment of 10,000 patients with malignant glioma, or 100,000 patients with new onset Parkinson's disease. Fifth, downstream manufacturing problems, such as nanomedicine lyophilization, must be solved to ensure the nanomedicine has a commercially viable shelf-life for treatment of CNS disease in humans.