Identification and epidemiological study of an uncultured flavivirus from ticks using viral metagenomics and pseudoinfectious viral particles.

During their blood-feeding process, ticks are known to transmit various viruses to vertebrates, including humans. Recent viral metagenomic analyses using next-generation sequencing (NGS) have revealed that blood-feeding arthropods like ticks harbor a large diversity of viruses. However, many of these viruses have not been isolated or cultured, and their basic characteristics remain unknown. This study aimed to present the identification of a difficult-to-culture virus in ticks using NGS and to understand its epidemic dynamics using molecular biology techniques. During routine tick-borne virus surveillance in Japan, an unknown flaviviral sequence was detected via virome analysis of host-questing ticks. Similar viral sequences have been detected in the sera of sika deer and wild boars in Japan, and this virus was tentatively named the Saruyama virus (SAYAV). Because SAYAV did not propagate in any cultured cells tested, single-round infectious virus particles (SRIP) were generated based on its structural protein gene sequence utilizing a yellow fever virus-based replicon system to understand its nationwide endemic status. Seroepidemiological studies using SRIP as antigens have demonstrated the presence of neutralizing antibodies against SAYAV in sika deer and wild boar captured at several locations in Japan, suggesting that SAYAV is endemic throughout Japan. Phylogenetic analyses have revealed that SAYAV forms a sister clade with the Orthoflavivirus genus, which includes important mosquito- and tick-borne pathogenic viruses. This shows that SAYAV evolved into a lineage independent of the known orthoflaviviruses. This study demonstrates a unique approach for understanding the epidemiology of uncultured viruses by combining viral metagenomics and pseudoinfectious viral particles.

A20 in hepatic stellate cells suppresses chronic hepatitis by inhibiting DCLK1-JNK pathway-dependent chemokines.

Hepatic stellate cells (HSCs) are responsible for liver fibrosis accompanied by its activation into myofibroblasts and the abundant production of extracellular matrix. However, the HSC contribution to progression of liver inflammation has been less known. We aimed to elucidate the mechanism in HSCs underlying the inflammatory response and the function of tumor necrosis factor α-related protein A20 (TNFAIP3). We established A20 conditional knockout (KO) mice crossing Twist2-Cre and A20 floxed mice. Using these mice, the effect of A20 was analyzed in mouse liver and HSCs. The human HSC line LX-2 was also used to examine the role and underlying molecular mechanism of A20. In this KO model, A20 was deficient in >80% of HSCs. Spontaneous inflammation with mild fibrosis was found in the liver of the mouse model without any exogenous agents, suggesting that A20 in HSCs suppresses chronic hepatitis. Comprehensive RNA sequence analysis revealed that A20-deficient HSCs exhibited an inflammatory phenotype and abnormally expressed chemokines. A20 suppressed JNK pathway activation in HSCs. Loss of A20 function in LX-2 cells also induced excessive chemokine expression, mimicking A20-deficient HSCs. A20 overexpression suppressed chemokine expression in LX-2. In addition, we identified DCLK1 in the genes regulated by A20. DCLK1 activated the JNK pathway and upregulates chemokine expression. DCLK1 inhibition significantly decreased chemokine induction by A20-silencing, suggesting that A20 controlled chemokine expression in HSCs via the DCLK1-JNK pathway. In conclusion, A20 suppresses chemokine induction dependent on the DCLK1-JNK signaling pathway. These findings demonstrate the therapeutic potential of A20 and the DCLK1-JNK pathway for the regulation of inflammation in chronic hepatitis.

Palliative use of self-expanding metal stents in initially anticancer treatment-intolerant patients with esophageal cancer.

BACKGROUND: The post-insertion clinical course of esophageal self-expandable metal stents (SEMS) in initially frail patients with esophageal carcinoma (EC) with dysphagia remains unclear. This study aimed to assess dysphagia improvement and evaluate prognosis in initially frail patients with advanced EC following SEMS insertion. METHODS: We retrospectively reviewed EC patients with EC who underwent esophageal SEMS insertion at our institution between January 2014 and March 2023. Inclusion criteria comprised Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥ 3 or ECOG PS 2 for individuals aged ≥ 75 years and recommendation for best supportive care by a multidisciplinary team. RESULTS: Forty-six patients met the inclusion criteria. Among them, 37 patients (80.4%) were ≥ 75 years old, and 21 patients (45.7%) exhibited ECOG PS 3 or 4. Dysphagia score (DS) ≥ 3 was observed in 27 patients (58.7%). All esophageal SEMS insertions were successfully completed. Post-procedure, there were two fatal cases of aspiration pneumonia and one perforation incident. DS improved to ≤ 1 in 25 patients (54.3%), with multivariate analysis indicating DS 3-4 and Glasgow Prognostic Score (GPS) 1-2 as negative predictive factors. The median overall survival was 4.1 months (95% confidence interval 1.8-6.5). CONCLUSIONS: Esophageal SEMS insertion effectively alleviated dysphagia in initially frail EC patients, yet prognosis remained poor, with occurrences of some fatal adverse events. Careful selection of candidates for esophageal SEMS insertions is crucial in this demographic, particularly considering the challenges in improving dysphagia for patients with DS 3-4 and GPS 1-2.

Optimization of transplantation methods using isolated mesenchymal stem/stromal cells: clinical trials of inflammatory bowel diseases as an example.

Mesenchymal stem/stromal cells (MSCs) are distributed in various tissues and are used in clinical applications as a source of transplanted cells because of their easy harvestability. Although MSCs express numerous cell-surface antigens, single-cell analyses have revealed a highly heterogeneous cell population depending on the original tissue and donor conditions, including age and interindividual differences. This heterogeneity leads to differences in their functions, such as multipotency and immunomodulatory effects, making it challenging to effectively treat targeted diseases. The therapeutic efficacy of MSCs is controversial and depends on the implantation site. Thus, there is no established recipe for the transplantation of MSCs (including the type of disease, type of origin, method of cell culture, form of transplanted cells, and site of delivery). Our recent preclinical study identified appropriate MSCs and their suitable transplantation routes in a mouse model of inflammatory bowel disease (IBD). Three-dimensional (3D) cultures of MSCs have been demonstrated to enhance their properties and sustain engraftment at the lesion site. In this note, we explore the methods of MSC transplantation for treating IBDs, especially Crohn's disease, from clinical trials published over the past decade. Given the functional changes in MSCs in 3D culture, we also investigate the clinical trials using 3D constructs of MSCs and explore suitable diseases that might benefit from this approach. Furthermore, we discuss the advantages of the prospective isolation of MSCs in terms of interindividual variability. This note highlights the need to define the method of MSC transplantation, including interindividual variability, the culture period, and the transplantation route.

Efficacy and safety of mirikizumab as induction and maintenance therapy for Japanese patients with moderately to severely active ulcerative colitis: a subgroup analysis of the global phase 3 LUCENT-1 and LUCENT-2 studies.

BACKGROUND/AIMS: Mirikizumab is a p19-directed anti-interleukin-23 antibody with potential efficacy against ulcerative colitis (UC). We evaluated the efficacy and safety of mirikizumab in a Japanese subpopulation with moderately to severely active UC from the LUCENT-1 and LUCENT-2 studies. METHODS: LUCENT-1 and LUCENT-2 were phase 3, randomized, double-blind, placebo-controlled trials of mirikizumab therapy in adults with moderately to severely active UC. LUCENT-1 was a 12-week induction trial where patients were randomized 3:1 to receive intravenous mirikizumab 300 mg or placebo every 4 weeks (Q4W). Patients achieving a clinical response with mirikizumab following the induction study were re-randomized 2:1 to double-blind treatment with either mirikizumab 200 mg or placebo subcutaneously Q4W during the 40-week maintenance study. The primary outcomes were clinical remission at week 12 of LUCENT-1 and week 40 of LUCENT-2. RESULTS: A total of 137 patients enrolled in Japan were randomized to mirikizumab (n = 102) or placebo (n = 35). Compared with placebo, patients who received mirikizumab showed numerically higher clinical remission at week 12 of induction (32.4% [n = 33] vs. 2.9% [n = 1]) and at week 40 of maintenance (48.9% [n = 23] vs. 28.0% [n = 7]). A greater number of patients achieved key secondary endpoints in the mirikizumab group compared with placebo. The frequency of treatment-emergent adverse events was similar across mirikizumab and placebo groups. Efficacy and safety results observed in the Japanese subpopulation were generally consistent with those in the overall population. CONCLUSIONS: Mirikizumab induction and maintenance treatments were effective in Japanese patients with moderately to severely active UC. No new safety concerns were identified.

Discovery of non-genomic drivers of YAP signaling modulating the cell plasticity in CRC tumor lines.

In normal intestines, a fetal/regenerative/revival cell state can be induced upon inflammation. This plasticity in cell fate is also one of the current topics in human colorectal cancer (CRC). To dissect the underlying mechanisms, we generated human CRC organoids with naturally selected genetic mutation profiles and exposed them to two different conditions by modulating the extracellular matrix (ECM). Among tested mutation profiles, a fetal/regenerative/revival state was induced following YAP activation via a collagen type I-enriched microenvironment. Mechanistically, YAP transcription was promoted by activating AP-1 and TEAD-dependent transcription and suppressing intestinal lineage-determining transcription via mechanotransduction. The phenotypic conversion was also involved in chemoresistance, which could be potentially resolved by targeting the underlying YAP regulatory elements, a potential target of CRC treatment.