Abstract: Mutations of the telomeric copy of the survival motor neuron 1 (SMN1) gene cause spinal muscular atrophy. A deletion of the Eef1a2 gene leads to lower motor neuron degeneration in wasted mice. Indirect evidences have been shown that the eEF1A protein family may interact with SMN, and our previous study showed that abnormalities of neuromuscular junctions in wasted mice were similar to those of Smn mutant mice. To determine potential colocalization between SMN and tissue-specific translation elongation factor 1A2 (eEF1A2), an immunochemical analysis of HeLa cells transfected with the plasmid pcDNA3.1(+)C-hEEF1A2- myc and a new quantitative test of colocalization by intensity correlation analysis (ICA) was used to explore the association of SMN and eEF1A2. Here the results showed that eEF1A2 redistributed from the cytoplasm to the nucleus in response to serum and epidermal growth factor. In the cytoplasm, compelling evidence showed that staining for myc-tagged eEF1A2 varied in synchrony with that for SMN, consistent with the formation of a SMN-eEF1A2 complex in the cytoplasm of HeLa cells. These findings suggest that eEF1A2 may colocalize with SMN in the cytoplasm and may be a component of the SMN complex. However, the limitation of the ICA method is an inability to resolve colocalization in components of small organelles such as the nucleus.
Abstract: Acute disseminated encephalomyelitis (ADEM) has
been reported to develop after a hymenoptera sting, but its
pathogenesis is not known in detail. Myelin basic protein (MBP)-
specific T cells have been detected in the blood of patients with
ADEM, and a proportion of these patients develop multiple sclerosis
(MS). In an attempt to understand the mechanisms underlying
ADEM, molecular mimicry between hymenoptera venom peptides
and the human immunodominant MBP peptide was scrutinized,
based on the sequence and structural similarities, whether it was the
root of the disease. The results suggest that the three wasp venom
peptides have low sequence homology with the human
immunodominant MBP residues 85-99. Structural similarity analysis
among the three venom peptides and the MS-related HLA-DR2b
(DRA, DRB1*1501)-associated immunodominant MHC
binding/TCR contact residues 88-93, VVHFFK showed that
hyaluronidase residues 7-12, phospholipase A1 residues 98-103, and
antigen 5 residues 109-114 showed a high degree of similarity
83.3%, 100%, and 83.3% respectively. In conclusion, some wasp
venom peptides, particularly phospholipase A1, may potentially act
as the molecular motifs of the human 3HLA-DR2b-associated
immunodominant MBP88-93, and possibly present a mechanism for
induction of wasp sting-associated ADEM.
Abstract: Bone marrow-derived stem cells have been widely
studied as an alternative source of stem cells. Mesenchymal stem
cells (MSCs) were mostly investigated and studies showed MSCs can
promote neurogenesis. Little is known about the non-mesenchymal
mononuclear cell fraction, which contains both hematopoietic and
nonhematopoietic cells, including monocytes and endothelial
progenitor cells. This study focused on unfractionated bone marrow
mononuclear cells (BMMCs), which remained 72 h after MSCs were
adhered to the culture plates. We showed that BMMC-conditioned
medium promoted morphological changes of human SH-SY5Y
neuroblastoma cells from an epithelial-like phenotype towards a
neuron-like phenotype as indicated by an increase in neurite
outgrowth, like those observed in retinoic acid (RA)-treated cells.
The result could be explained by the effects of trophic factors
released from BMMCs, as shown in the RT-PCR results that
BMMCs expressed nerve growth factor (NGF), brain-derived
neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF).
Similar results on the cell proliferation rate were also observed
between RA-treated cells and cells cultured in BMMC-conditioned
medium, suggesting that cells creased proliferating and differentiated
into a neuronal phenotype. Using real-time RT-PCR, a significantly
increased expression of tyrosine hydroxylase (TH) mRNA in SHSY5Y
cells indicated that BMMC-conditioned medium induced
catecholaminergic identities in differentiated SH-SY5Y cells.