ABSTRACT
Group 3 late embryogenesis abundant (G3LEA) proteins have amino acid sequences with characteristic 11-mer motifs and are known to reduce aggregation of proteins during dehydration. Previously, we clarified the structural and thermodynamic properties of the 11-mer repeating units in G3LEA proteins using synthetic peptides composed of two or four tandem repeats originating from an insect (Polypedilum vanderplanki), nematodes and plants. The purpose of the present study is to test the utility of such 22-mer peptides as protective reagents for aggregation-prone proteins. For lysozyme, desiccation-induced aggregation was abrogated by low molar ratios of a 22-mer peptide, PvLEA-22, derived from a P. vanderplanki G3LEA protein sequence. However, an unexpected behavior was noted for the milk protein, α-casein. On drying, the resultant aggregation was significantly suppressed in the presence of PvLEA-22 with its molar ratios>25 relative to α-casein. However, when the molar ratio was <10, aggregation occurred on addition of PvLEA-22 to aqueous solutions of α-casein. Other peptides derived from nematode, plant and randomized G3LEA protein sequences gave similar results. Such an anomalous solubility change in α-casein was shown to be due to a pH shift to ca. 4, a value nearly equal to the isoelectric point (pI) of α-casein, when any of the 22-mer peptides was mixed. These results demonstrate that synthetic peptides derived from G3LEA protein sequences can reduce protein aggregation caused both by desiccation and, at high molar ratios, also by pH effects, and therefore have potential as stabilization reagents.
Subject(s)
Bacterial Proteins/chemistry , Caseins/chemistry , Helminth Proteins/chemistry , Insect Proteins/chemistry , Muramidase/chemistry , Peptides/chemical synthesis , Plant Proteins/chemistry , Animals , Chemical Precipitation , Chironomidae/chemistry , Comamonadaceae/chemistry , Desiccation , Hydrogen-Ion Concentration , Kinetics , Nematoda/chemistry , Plants/chemistry , Protein Structure, Secondary , Solid-Phase Synthesis Techniques , ThermodynamicsABSTRACT
In order to clarify the clinical characteristics and effects of acetylcholinesterase inhibitors of patients with generalized myasthenia gravis with antibodies to muscle specific kinase (MuSK), we investigated seven patients with MuSK antibodies and eleven patients without both antibodies of acetylcholine receptor and MuSK. All patients with MuSK antibodies showed bulbar symptoms, which frequency was significantly higher compared to those in patients without double antibodies. The frequency of positive result of Tensilon test was significantly lower in patients with MuSK antibodies than in those without double antibodies. In response to intravenous edrophonium chloride, MuSK positive patients showed adverse reactions in a small dosage of edrophonium chloride, less than 5 mg, such as fasciculation on facial muscles and stuffy sensation of throat. The adverse responses to a small dosage of intravenous edrophonium chloride injection is useful information to distinguish patients with seronegative generalized MG, whether they have MuSK antibodies or not. When acetylcholinesterase inhibitors medication is tried to patients with MuSK antibodies, if necessary, a small dosage of inhibitors should be used to avoid cholinergic hypersensitivity.
Subject(s)
Autoantibodies/blood , Cholinesterase Inhibitors/therapeutic use , Myasthenia Gravis/drug therapy , Myasthenia Gravis/immunology , Receptor Protein-Tyrosine Kinases/immunology , Receptors, Cholinergic/immunology , Adult , Aged , Cholinesterase Inhibitors/administration & dosage , Female , Humans , Male , Middle AgedSubject(s)
Adrenergic alpha-Agonists , Cocaine , Dopamine Uptake Inhibitors , Parkinson Disease/diagnosis , Phenylephrine , Pupil/drug effects , Adrenergic alpha-Agonists/administration & dosage , Aged , Cocaine/administration & dosage , Dopamine Uptake Inhibitors/administration & dosage , Female , Humans , Male , Middle Aged , Mydriasis/chemically induced , Ophthalmic Solutions , Phenylephrine/administration & dosage , Sympathetic Nervous SystemABSTRACT
Parkinson's disease is characterized by dopaminergic neuronal death and the presence of Lewy bodies. alpha-Synuclein is a major component of Lewy bodies, but the process of its accumulation and its relationship to dopaminergic neuronal death has not been resolved. Although the pathogenesis has not been clarified, mitochondrial complex I is suppressed, and caspase-3 is activated in the affected midbrain. Here we report that a combination of 1-methyl-4-phenylpyridinium ion (MPP(+)) or rotenone and proteasome inhibition causes the appearance of alpha-synuclein-positive inclusion bodies. Unexpectedly, however, proteasome inhibition blocked MPP(+)- or rotenone-induced dopaminergic neuronal death. MPP(+) elevated proteasome activity, dephosphorylated mitogen-activating protein kinase (MAPK), and activated caspase-3. Proteasome inhibition reversed the MAPK dephosphorylation and blocked caspase-3 activation; the neuroprotection was blocked by a p42 and p44 MAPK kinase inhibitor. Thus, the proteasome plays an important role in both inclusion body formation and dopaminergic neuronal death but these processes form opposite sides on the proteasome regulation in this model.
