Biomedical subjects

Jun-Ichi Kawada

Publications and source records attributed to Jun-Ichi Kawada.

8 recordsLinked to original sources

PubMed2026

A Patient-Derived iPSC-Based Model Reveals Neural Lineage-Specific Transcription of Endogenous HHV-6B.

BACKGROUND: Endogenous human herpesvirus 6 (eHHV-6), in which the entire viral genome is integrated into human chromosomes, is present in approximately 1% of the population and has been associated with various clinical conditions, including neurological disorders. However, its biological significance remains unclear due to the lack of appropriate experimental models. METHODS: We established a patient-derived induced pluripotent stem cell (iPSC)-based tissue culture model using lymphoblastoid cell lines from individuals with eHHV-6B. iPSCs retaining the integrated viral genome were generated and subsequently differentiated into neural stem cells (NSCs). Viral gene expression was evaluated by RT-qPCR under basal conditions and following chemical stimulation. RESULTS: The integrated HHV-6B genome was transcriptionally silent in iPSCs but exhibited spontaneous low-level expression of the immediate-early gene U90 and the late gene U100 in NSCs. Chemical stimulation further enhanced U90 expression, whereas induction of U100 did not reach statistical significance. These findings indicate preferential activation of early viral transcriptional programs in neural lineage cells. CONCLUSIONS: Neural lineage cells provide a permissive environment for expression of eHHV-6B transcripts. This patient-derived iPSC-based model provides a platform for investigating the biological significance of neural lineage-specific eHHV-6 transcripts and may facilitate interpretation of HHV-6 DNA detection in patients with eHHV-6 by enabling studies of cell type-dependent viral transcription.

endogenous HHV-6↗

PubMed2026

Comprehensive Viral Detection and Profiling of Plasma Cell-Free RNA in Patients With Suspected Hemophagocytic Lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a severe, rapidly progressive disease. While viral infection is considered a common etiology of pediatric HLH, specific causative viruses other than the Epstein-Barr virus (EBV) have been rarely identified. This study utilized metagenomic next-generation sequencing (NGS) to identify potential causative pathogens in plasma samples from 17 pediatric patients with suspected HLH. Additionally, one case each of confirmed EBV- and cytomegalovirus (CMV)-associated HLH was analyzed for methodological validation. Plasma cell-free RNA (cfRNA) profiling was performed using NGS data to assess the host transcriptome response. Significant viral reads of human herpesvirus-6B, human herpesvirus-7, and Hubei reo-like virus (HRLV) 14 were detected using metagenomic NGS in one patient each. Plasma cfRNA profiles from five patients with viral infection (including EBV and CMV) were compared to those of 14 patients without viral infection. By comparing the two patient groups, 1053 differentially expressed genes were identified. The gene ontology (GO) term of "adaptive immune response" (GO: 0002250) was significantly enriched among upregulated genes in the virus-positive group. Furthermore, an isolated cluster consisting specifically of mitochondrial RNAs, was identified in the upregulated genes of the virus-positive group. Using metagenomic NGS, several candidate viral pathogens were identified in patients with suspected infection-related HLH. The viral genome of HRLV 14, previously undetected in human clinical samples, was identified in one patient. The results from plasma cfRNA profiling suggest that mitochondrial RNAs may reflect the underlying pathogenesis of virus-associated HLH and have potential utility as disease biomarkers.

Humans↗

PubMed2025

Plasma Proteomic Profiles of Pediatric Patients With Human Herpesvirus 6B Encephalitis Following Umbilical Cord Blood Transplantation.

Human herpesvirus 6B (HHV-6B) encephalitis is a rare but severe complication of hematopoietic cell transplantation. This study investigated the pathogenesis of HHV-6B encephalitis by comparing plasma proteomic profiles of four pediatric patients with HHV-6B encephalitis to three with asymptomatic HHV-6B reactivation following umbilical cord blood transplantation (UCBT). Plasma proteomic profiling was conducted using liquid chromatography-mass spectrometry. Overall, 260 proteins were identified and quantified in plasma samples. At the onset of HHV-6B encephalitis and asymptomatic reactivation, 20 and 24 proteins, respectively, were significantly upregulated compared to their respective pre-onset levels. Of these, 11 proteins were uniquely upregulated in HHV-6B encephalitis. S100-A9 and S100-A8 were the most and second-most upregulated proteins in HHV-6B encephalitis, respectively. Elevated plasma S100A8/A9 heterodimer levels were confirmed via enzyme-linked immunosorbent assay in three of the four patients with HHV-6B encephalitis. Pathway analysis identified neutrophil degranulation as the most enriched category among upregulated proteins in HHV-6B encephalitis. Additionally, proteins related to the protein-lipid complex remodeling pathway were more prominently upregulated in HHV-6B encephalitis than in asymptomatic reactivation. Proteomic analysis revealed distinct plasma protein profiles between HHV-6B encephalitis and asymptomatic HHV-6B reactivation in pediatric UCBT recipients. The inflammatory response mediated by S100A8/A9 proteins may play a critical role in the pathogenesis of HHV-6B encephalitis. These findings indicate that proteomic analysis may provide novel insights into the host response to HHV-6B reactivation and the subsequent development of HHV-6B encephalitis.

Humans↗

PubMed2006

Evaluation of apoptosis in Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis.

Epstein-Barr virus (EBV) is known to be a causative agent of hemophagocytic lymphohistiocytosis (HLH). To investigate association of apoptosis in the pathogenesis of EBV-associated HLH, the serum EBV loads, and serum concentrations of soluble tumor necrosis factor receptor 1 (sTNF-R1), soluble Fas ligand, and cytochrome c were examined in 15 patients with EBV-associated HLH and 24 patients with infectious mononucleosis (IM). Levels of sTNF-R1 are known to reflect the biological activity of TNF-alpha and cytochrome c is a specific marker of apoptosis. EBV loads, and concentrations of sTNF-R1 and cytochrome c were significantly higher in patients with EBV-associated HLH than in patients with IM. On the other hand, there were no statistically significant differences in the concentrations of soluble Fas ligand. In patients with EBV-associated HLH, EBV loads, concentrations of sTNF-R1, and cytochrome c were correlated with each other. These results suggest that apoptosis, which is dependent on the EBV load and could be mediated by TNF-alpha, plays a major role in the pathophysiology of EBV-associated HLH.

Apoptosis↗

PubMed2006

Analysis of gene-expression profiles by oligonucleotide microarray in children with influenza.

In order to clarify the mechanism of the host response to influenza virus, gene-expression profiles of peripheral blood obtained from paediatric patients with influenza were investigated by oligonucleotide microarray. In the acute phase of influenza, 200 genes were upregulated and 20 genes were downregulated compared with their expression in the convalescent phase. Interferon-regulated genes, such as interferon-induced protein with tetratricopeptide repeats 2 (IFIT2) and vipirin, were strongly upregulated in the acute phase. Gene ontology analysis showed that immune response genes were highly overrepresented among the upregulated genes. Gene-expression profiles of influenza patients with and without febrile convulsion were also studied. In patients with febrile convulsion, 22 genes were upregulated and five were downregulated compared with their expression in patients without febrile convulsion. These results should help to clarify the pathogenesis of influenza and its neurological complications.

Acute Disease↗

PubMed2005

Differences between T cell-type and natural killer cell-type chronic active Epstein-Barr virus infection.

Infections of T cells and natural killer (NK) cells play a central role in the pathogenesis of chronic active Epstein-Barr virus (CAEBV) infection. To characterize the virologic and cytokine profiles of T cell-type and NK cell-type infection, 39 patients with CAEBV infection were analyzed. Patients with T cell-type infection had higher titers of immunoglobulin G against early and late EBV antigens, suggesting lytic cycle infection. However, the pattern of EBV gene expression was latency type II; BZLF1, which is a hallmark of lytic cycle infection, could not be detected in any patients, regardless of infection type. Patients with CAEBV infection had high concentrations of proinflammatory, T helper cell type 1, and anti-inflammatory cytokines. The cytokine profile in patients with NK cell-type infection was similar to that in patients with T cell-type infection, but the concentration of IL-13 was high in patients with NK cell-type infection. These findings should help to clarify the pathogenesis of CAEBV infection and facilitate the development of more-effective treatments.

Adolescent↗

PubMed2004

Hemiconvulsion-hemiplegia syndrome and primary human herpesvirus 7 infection.

We report a case of hemiconvulsion-hemiplegia (HH) syndrome. An 18-month-old female infant had a hemiconvulsion followed by left hemiplegia. Magnetic resonance imaging immediately after the onset of hemiplegia showed high intensity in the right hemisphere in diffusion-weighted images (DWI), while T1- and T2-weighted images were normal. Single photon emission computed tomography showed hypoperfusion of the right hemisphere in the acute phase. Virological analyses proved primary human herpesvirus 7 (HHV-7) infection. DWI are useful for the early evaluation of HH syndrome. Vascular disorders due to HHV-7 infection may have been related to the development of HH syndrome in this patient.

Cerebral Cortex↗

PubMed2003

Absence of associations between influenza-associated encephalopathy and human herpesvirus 6 or human herpesvirus 7.

BACKGROUND: Influenza-associated encephalopathy is a severe complication of influenza virus infection, but its pathogenesis is unknown. It was recently suggested that the neurologic complications of influenza, including encephalopathy, are associated with human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7). AIM To confirm or refute the association between influenza-associated encephalopathy and HHV-6 or HHV-7. METHODS: Cerebrospinal fluid and serum from 25 patients with central nervous system complications of influenza (18 patients with encephalopathy and 7 patients with febrile convulsions) were investigated. The specimens were examined by real time polymerase chain reaction (PCR) and nested PCR for HHV-6 and HHV-7 DNA. RESULTS: In the cerebrospinal fluid samples neither HHV-6 DNA nor HHV-7 DNA was detected by real time PCR or nested PCR. HHV-6 DNA was detected in a single serum sample from a patient with febrile convulsions. CONCLUSION: In our study there was no association with HHV-6 or HHV-7 in most patients with central nervous system complications of influenza.

Age Distribution↗