[Effects of TNF-α on ICAM-1 and LFA-1 expression in peripheral blood mononuclear cells of children with febrile seizures].

OBJECTIVE: To study the effects of TNF-α on ICAM-1 and LFA-1 expression in peripheral blood mononuclear cells (PBMC) of children with febrile seizures (FS). METHODS: Sixteen children with FS and 16 age- and gender-matched healthy children were enrolled. The samples of PBMC from FS children were randomized into two groups with or without TNF-α treatment (TNF-α concentration 1.0 ng/mL). PBMC were purified and cultured with a conventional method in vitro. The expression of ICAM-1 and LFA-1 in PBMC was determined by flow cytometry (FCM). RESULTS: ICAM-1ï¼»(20±9)% vs (14±7)%)ï¼½and LFA-1ï¼»(43±16)% vs (30±16)%ï¼½expression in PBMC in the untreated FS group was significantly higher than that in the normal control group (P<0.05). Compared with the untreated FS group, the treatment with TNF-α remarkably increased the ICAM-1 expressionï¼»(27±11)%ï¼½(P<0.05). PBMC LFA-1 expressionï¼»(52±21)%ï¼½in the TNF-α-treated group was higher than that in the untreated FS group, although there were no statistical differences between the two groups. CONCLUSIONS: TNF-α treatment may increase LFA-1 and ICAM-1 expression in PBMC of children with FS.

[Hypersensitivity syndrome reactions to antiepileptic drugs, clinical characteristic and association with HLA-B*1502].

OBJECTIVE: To investigate the cutaneous adverse reactions to antiepileptic drugs (AEDs), clinical characteristic and the association with HLA-B*1502. METHODS: A retrospective analysis of four cases of antiepileptic drug hypersensitive syndrome (AHS) were performed on the basis of clinical data, cutaneous adverse reactions to carbamazepine (CBZ) (n = 2) including Stevens-Johnson syndrome (SJS) (n = 1) and hypersensitivity syndrome (HSS) (n = 1); phenobarbital-induced HSS (n = 1) and oxcarbazepine (OXC)-induced HSS (n = 1). All patients received the examinations of polymerase chain reaction (PCR) with sequence specific primers to analyze HLA-B*1502. Two healthy subjects had no history of using antiepileptic drugs as the control. RESULTS: All patients had manifestations of fever, eruption, mucosal involvement and visceral injury. Two cases were diagnosed as Stevens-Johnson syndrome associated with apparent bullae formation. Genotype positive for HLA-B*1502 was association with 2 patients with CBZ/OXC-induced SJS while the other 1 case of CBZ and 1 case of phenobarbital-induced HSS were genotype non-HLA-B*1502. CONCLUSION: AHS usually occurs within 1 to 2 weeks after initiation of AEDs therapy. The typical presentations are fever, eruption and internal organ involvements, etc. The epileptic patients with CBZ/OXC-induced SJS are related with HLA-B*1502 genotype. But it is not found in HSS patients.

Polyglutamine-expanded ataxin-7 decreases nuclear translocation of NF-kappaB p65 and impairs NF-kappaB activity by inhibiting proteasome activity of cerebellar neurons.

Our recent study indicated that polyglutamine-expanded ataxin-7-Q75 induced apoptotic death of cultured cerebellar neurons by downregulating Bcl-x(L) expression and activating mitochondrial apoptotic cascade. Mutant polyglutamine-expanded proteins are believed to impair the proteolytic function of ubiquitin-proteasome system by sequestering components of proteasomes. Proteasome degradation of IkappaBalpha permits nuclear translocation of NF-kappaB and is required for continuous NF-kappaB activity, which supports the survival of cultured cerebellar neurons by inducing Bcl-x(L) expression. Thus, we tested the hypothesis that mutant ataxin-7-Q75 causes proteasome dysfunction and impairs NF-kappaB activity, leading to reduced Bcl-x(L) expression, caspase activation and cerebellar neuronal death. EMSA assays indicate that DNA-binding activity of NF-kappaB was significantly decreased in cerebellar neurons expressing ataxin-7-Q75. Similar to mutant ataxin-7-Q75, NF-kappaB inhibitor APEQ induced cerebellar neuronal death by decreasing Bcl-x(L) expression and activating caspase-9. Mutant ataxin-7-Q75 inhibited the proteolytic activity of proteasomes in cerebellar neurons. Proteasome inhibitor MG132 also caused cerebellar neuronal death by decreasing Bcl-x(L) expression and activating caspase-9. Both ataxin-7-Q75 and MG132 caused the cytosolic accumulation of IkappaBalpha in cerebellar neurons. Mutant ataxin-7-Q75 or MG132 increased the cytosolic level of NF-kappaB p65 and decreased the nuclear NF-kappaB p65 level. Our study provides the evidence that polyglutamine-expanded ataxin-7-Q75 decreases nuclear translocation of NF-kappaB p65 and impairs NF-kappaB activity by inhibiting proteasome activity of cerebellar neurons.

Polyglutamine-expanded ataxin-7 activates mitochondrial apoptotic pathway of cerebellar neurons by upregulating Bax and downregulating Bcl-x(L).

Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant neurodegenerative disorder caused by polyglutamine-expanded ataxin-7. In the present investigation, we expressed disease-causing mutant ataxin-7-Q75 in the primary neuronal culture of cerebellum with the aid of recombinant adenoviruses. Subsequently, this in vitro cellular model of SCA7 was used to study the molecular mechanism by which mutant ataxin-7-Q75 induces neuronal death. TUNEL staining studies indicated that polyglutamine-expanded ataxin-7-Q75 caused apoptotic cell death of cultured cerebellar neurons. Mutant ataxin-7-Q75 induced the formation of active caspase-3 and caspase-9 without activating caspase-8. Polyglutamine-expanded ataxin-7-Q75 promoted the release of apoptogenic cytochrome-c and Smac from mitochondria, which was preceded by the downregulation of Bcl-x(L) protein and upregulation of Bax protein expression in cultured cerebellar neurons. Further real-time TaqMan RT-PCR assays showed that mutant ataxin-7-Q75 upregulated Bax mRNA level and downregulated Bcl-x(L) mRNA expression in the primary neuronal culture of cerebellum. The present study provides the evidence that polyglutamine-expanded ataxin-7-Q75 activates mitochondria-mediated apoptotic cascade and induces neuronal death by upregulating Bax expression and downregulating Bcl-x(L) expression of cerebellar neurons.