ABSTRACT
Vitamin B12 (cobalamin) deficiency is prevalent worldwide and causes megaloblastic anemia and neurologic deficits. While the anemia can be treated, the neurologic deficits can become refractive to treatment as the disease progresses. Therefore, timely intervention is critical for a favorable outcome. Moreover, the metabolic basis for the neuro-pathologic changes and the role of cobalamin deficiency in the pathology still remains unexplained. Using a transcobalamin receptor / CD320 knockout mouse that lacks the receptor for cellular uptake of transcobalamin bound cobalamin, we aimed to determine whether cobalamin deficiency in the central nervous system produced functional neurologic deficits in the mouse that would parallel those observed in humans. Our behavioral analyses indicate elevated anxiety and deficits in learning, memory and set-shifting of a spatial memory task in the KO mouse. Consistent with the behavioral deficits, the knockout mouse shows impaired expression of the early phase of hippocampal long-term potentiation along with reduced expression of GluR1, decreased brain mass and a significant reduction in the size of nuclei of the hippocampal pyramidal neurons. Our study suggests that the CD320 knockout mouse develops behavioral deficits associated with cobalamin deficiency and therefore could provide a model to understand the metabolic and genetic basis of neuro-pathologic changes due to cobalamin deficiency.
Subject(s)
Hippocampus/pathology , Receptors, Cell Surface/genetics , Vitamin B 12 Deficiency/genetics , Animals , Anxiety Disorders/genetics , Avoidance Learning , Behavior, Animal , Learning , Memory/physiology , Mice, Inbred C57BL , Mice, Knockout , Neurons/pathology , Pyramidal Cells/pathology , Receptors, AMPA/metabolismABSTRACT
A new series of ferrocenyl selenoamides 7-11 (FcSeNH(CH(2))(n)CH(2)(R)OH, n = 1, 2, 3, R = H, Me, Ph) were prepared in good yields by selenative demetalation of Fischer aminocarbene complexes. The crystal structures of 7 [FcSeNH(CH(2))(2)OH] and 19 [PhSeNH(CH(2))(2)OH] reveal their capability to form intermolecular hydrogen bonding in solid state. Results of SRB assays show that these new selenium compounds have a good anticancer potency superior to tamoxifen and cisplatin, with IC(50) values ranging from 4.5 to 13.32 µM against human breast cancer cell lines. A preliminary model to explain the structure-cytotoxic activity relation is proposed where different structural parameters such as the alkyl chain length, the presence of bulky groups in the same chain, the effect of hydroxyl group, and also the role of ferrocene moiety are included as being responsible for the cytotoxic response.
Subject(s)
Amides/chemical synthesis , Antineoplastic Agents/chemical synthesis , Coordination Complexes/chemical synthesis , Ferrous Compounds/chemical synthesis , Organoselenium Compounds/chemical synthesis , Amides/chemistry , Amides/pharmacology , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Coordination Complexes/chemistry , Coordination Complexes/pharmacology , Crystallography, X-Ray , Drug Screening Assays, Antitumor , Ferrous Compounds/chemistry , Ferrous Compounds/pharmacology , Humans , Inhibitory Concentration 50 , Metallocenes , Organoselenium Compounds/chemistry , Organoselenium Compounds/pharmacology , Structure-Activity RelationshipABSTRACT
Early Alzheimer's disease (AD) pathophysiology is characterized by synaptic changes induced by degradation products of amyloid precursor protein (APP). The exact mechanisms of such modulation are unknown. Here, we report that nanomolar concentrations of intraaxonal oligomeric (o)Abeta42, but not oAbeta40 or extracellular oAbeta42, acutely inhibited synaptic transmission at the squid giant synapse. Further characterization of this phenotype demonstrated that presynaptic calcium currents were unaffected. However, electron microscopy experiments revealed diminished docked synaptic vesicles in oAbeta42-microinjected terminals, without affecting clathrin-coated vesicles. The molecular events of this modulation involved casein kinase 2 and the synaptic vesicle rapid endocytosis pathway. These findings open the possibility of a new therapeutic target aimed at ameliorating synaptic dysfunction in AD.
