Identification of differentially expressed genes in blood cells of narcolepsy patients

Incoming human papillomavirus 16 genome is lost in PML protein-deficient HaCaT keratinocytes

Human papillomaviruses (HPVs) target promyelocytic leukemia (PML) nuclear bodies (NBs) during infectious entry and PML protein is important for efficient transcription of incoming viral genome. However, the transcriptional down regulation was shown to be promoter-independent in that heterologous promoters delivered by papillomavirus particles were also affected. To further investigate the role of PML protein in HPV entry, we used small hairpin RNA to knockdown PML protein in HaCaT keratinocytes. Confirming previous findings, PML knockdown in HaCaT cells reduced HPV16 transcript levels significantly following infectious entry without impairing binding and trafficking. However, when we quantified steady-state levels of pseudogenomes in interphase cells, we found strongly reduced genome levels compared with parental HaCaT cells. Because nuclear delivery was comparable in both cell lines, we conclude that viral pseudogenome must be removed after successful nuclear delivery. Transcriptome analysis by gene array revealed that PML knockdown in clonal HaCaT cells was associated with a constitutive interferon response. Abrogation of JAK1/2 signaling prevented genome loss, however, did not restore viral transcription. In contrast, knockdown of PML protein in HeLa cells did not affect HPV genome delivery and transcription. HeLa cells are transformed by HPV18 oncogenes E6 and E7, which have been shown to interfere with the JAK/Stat signaling pathway. Our data imply that PML NBs protect incoming HPV genomes. Furthermore, they provide evidence that PML NBs are key regulators of the innate immune response in keratinocytes.

IMPORTANCE

Promyelocytic leukemia nuclear bodies (PML NBs) are important for antiviral defense. Many DNA viruses target these subnuclear structures and reorganize them. Reorganization of PML NBs by viral proteins is important for establishment of infection. In contrast, HPVs require the presence of PML protein for efficient transcription of incoming viral genome. Our finding that PML protein prevents the loss of HPV genome following infection implies that the host cell may be able to recognize chromatinized HPV genome or the associated capsid proteins. A constitutively active interferon response in absence of PML protein suggests that PML NBs are key regulators of the innate immune response in keratinocytes.

Genome-wide gene expression profiling of human narcolepsy

The objective of this study was to perform global gene expression profiling of patients affected by narcolepsy with cataplexy (NRLCP). This enabled identifying new potential biomarkers and relevant molecules possibly involved in the disease pathogenesis. In this study 10 NRLCP patients and 10 healthy controls were compared. Total RNA isolated from blood specimens was analyzed using microarray technology followed by statistical data analysis to detect genome-wide differential gene expression between patients and controls. Functional analysis of the gene list was performed in order to interpret the biological significance of the data. One hundred and seventy-three genes showed significant (p < 0.01) differential expression between the two tested conditions. The biological interpretation allowed categorizing differentially expressed genes involved in neurite outgrowth/extension and brain development, which could be possibly regarded as peripheral markers of the disease. Moreover, the NRLCP-related gene expression profiles indicated a dysregulation of metabolic and immune-related mechanisms. In conclusion, the gene expression profile associated to NRLCP suggested that molecular markers of neurological impairment, dysmetabolic and immune-related mechanisms, can be detected in blood of NRLCP patients.

Anti-Tribbles homolog 2 autoantibodies in Japanese patients with narcolepsy

STUDY OBJECTIVES

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness and cataplexy. The association with human leukocyte antigen (HLA)-DQB1*0602 and T-cell receptor alpha locus suggests that autoimmunity plays a role in narcolepsy. A recent study reported an increased prevalence of autoantibodies against Tribbles homolog 2 (TRIB2) in patients with narcolepsy. To replicate this finding, we examined anti-TRIB2 autoantibodies in Japanese patients with narcolepsy.

DESIGN

We examined anti-TRIB2 autoantibodies against a full-length [35S]-labeled TRIB2 antigen in Japanese patients with narcolepsy-cataplexy (n = 88), narcolepsy without cataplexy (n = 18), and idiopathic hypersomnia with long sleep time (n = 11). The results were compared to Japanese healthy controls (n = 87). Thirty-seven healthy control subjects were positive for HLA-DRB1*1501-DQB1*0602. We also examined autoantibodies against another Tribbles homolog, TRIB3, as an experimental control.

MEASUREMENTS AND RESULTS

Autoantibodies against TRIB2 were found in 26.1% of patients with narcolepsy-cataplexy, a significantly higher prevalence than the 2.3% in healthy controls. We found that anti-TRIB3 autoantibodies were rare in patients with narcolepsy and showed no association with anti-TRIB2 indices. No significant correlation was found between anti-TRIB2 positivity and clinical information.

CONCLUSIONS

We confirmed the higher prevalence and specificity of anti-TRIB2 autoantibodies in Japanese patients with narcolepsy-cataplexy. This suggests a subgroup within narcolepsy-cataplexy might be affected by an anti-TRIB2 autoantibody-mediated autoimmune mechanism.

The genetics of sleep disorders in humans: narcolepsy, restless legs syndrome, and obstructive sleep apnea syndrome

Sleep disorders are a group of neurological disorders known to cause public health problems associated with interference with daily activities including cognitive problems, poor job performance and reduced productivity. There is strong evidence emerging for the presence of genes influencing sleep disorders, such as narcolepsy (NRCLP), restless legs syndrome (RLS), and obstructive sleep apnea syndrome (OSAS). NRCLP is typically characterized by excessive daytime sleepiness, cataplexy, sleep paralysis and hallucinations. RLS is manifested by compelling need to move the legs and usually experienced when trying to sleep. OSAS is major sleep problem characterized by recurrent episodes of upper airway collapse and obstruction during sleep. In the recent years, many research groups have attempted to identify the susceptibility and candidate genes for NRCLP, RLS, and OSAS through the sequential analyses of genetic linkage and association. The purpose of this review is to summarize some of remarkable molecular advances in sleep and sleep disorders, thereby providing a greater understanding of the complex sleep processes, and a platform for future therapeutic interventions.

MX2 gene expression tends to be downregulated in subjects with HLA-DQB1*0602

OBJECTIVE

There is a close association between narcolepsy and the human leukocyte antigen (HLA)-DQB1*0602. The detailed influence and function of this specific HLA allele with regard to narcolepsy have not yet been elucidated. Our previous report identified the myxovirus resistance 2 (MX2) gene as a narcolepsy-specific dysregulated gene; however, the report had a limitation-the control groups were not HLA matched. In this study, we examined the possibility of an association between MX2 expression and HLA haplotypes.

DESIGNS

The expression levels of the MX2 gene in 3 groups (24 narcolepsy with cataplexy patients; 24 age-, sex-, and HLA-DQB1 genotype-matched controls; and 24 age- and sex-matched controls without the HLA-DQB1*0602 allele) were measured by quantitative real-time RT-PCR.

RESULTS

The expression level of the MX2 gene tended to be downregulated in subjects carrying HLA-DQB1*0602, compared with that of the control subjects without this allele. There was no difference in the MX2 expression level between the narcolepsy subjects and the HLA-DQB1 genotype-matched control subjects.

CONCLUSION

Our previous finding-the narcolepsy-specific reduction of MX2 gene expression-was not replicated in this follow-up study. The expression level of the MX2 gene in white blood cells was found to be lower in subjects with the HLA-DQB1*0602 than in subjects without this allele, suggesting that there exists a relationship between the HLA-DQB1*0602 allele and MX2 gene expression. This might be a possible explanation for the strong HLA association observed in narcolepsy.