Myeloid TLR4 signaling promotes post-injury withdrawal resolution of murine liver fibrosis.

The fate of resolution of liver fibrosis after withdrawal of liver injury is still incompletely elucidated. Toll-like receptor 4 (TLR4) in tissue fibroblasts is pro-fibrogenic. After withdrawal of liver injury, we unexpectedly observed a significant delay of fibrosis resolution as TLR4 signaling was pharmacologically inhibited in vivo in two murine models. Single-cell transcriptome analysis of hepatic CD11b+ cells, main producers of matrix metalloproteinases (MMPs), revealed a prominent cluster of restorative Tlr4-expressing Ly6c2-low myeloid cells. Delayed resolution after gut sterilization suggested its microbiome-dependent nature. Enrichment of a metabolic pathway linking to a significant increase of bile salt hydrolase-possessing family Erysipelotrichaceae during resolution. Farnesoid X receptor-stimulating secondary bile acids including 7-oxo-lithocholic acids upregulated MMP12 and TLR4 in myeloid cells in vitro. Fecal material transplant in germ-free mice confirmed phenotypical correlations in vivo. These findings highlight a pro-fibrolytic role of myeloid TLR4 signaling after injury withdrawal and may provide targets for anti-fibrotic therapy.

Enrichment of type I interferon signaling in colonic group 2 innate lymphoid cells in experimental colitis.

Group 2 innate lymphoid cells (ILC2s) serve as frontline defenses against parasites. However, excluding helminth infections, it is poorly understood how ILC2s function in intestinal inflammation, including inflammatory bowel disease. Here, we analyzed the global gene expression of ILC2s in healthy and colitic conditions and revealed that type I interferon (T1IFN)-stimulated genes were up-regulated in ILC2s in dextran sodium sulfate (DSS)-induced colitis. The enhancement of T1IFN signaling in ILC2s in DSS-induced colitis was correlated with the downregulation of cytokine production by ILC2s, such as interleukin-5. Blocking T1IFN signaling during colitis resulted in exaggeration of colitis in both wild-type and Rag2-deficient mice. The exacerbation of colitis induced by neutralization of T1IFN signaling was accompanied by reduction of amphiregulin (AREG) in ILC2s and was partially rescued by exogenous AREG treatment. Collectively, these findings show the potential roles of T1IFN in ILC2s that contribute to colitis manifestation.

DOCK2 is involved in the host genetics and biology of severe COVID-19.

Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge1-5. Here we conducted a genome-wide association study (GWAS) involving 2,393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3,289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target.

Association between Serum Biotin Levels and Cedar Pollinosis in Japanese Schoolchildren.

Biotin is a water-soluble B complex vitamin and coenzyme of five types of carboxylase and plays crucial roles in fatty acid, glucose, and amino acid metabolism. Nutritional biotin deficiency and defective enzymes essential for biotin metabolism cause inflammatory diseases such as eczema-like dermatitis and Crohn's disease; however, little is known about the pathophysiological roles of biotin. This study investigated the relationship between biotin metabolism and human allergic sensitization and diseases by measuring serum levels of biotin, total immunoglobulin E (IgE) and allergen-specific IgEs in more than 400 Japanese schoolchildren aged 6 to 12. The prevalence of allergic diseases, and environmental and life-style factors were also examined by a questionnaire. Like total IgE, serum biotin levels of children showed a log-normal distribution. Meanwhile, Spearman's rank correlation analysis showed weak but significant positive associations between serum biotin levels and total IgE (rho=0.147, p=0.0029) as well as allergen-specific IgEs against egg whites (rho=0.215, p=0.00013), cedar pollen (rho=0.176, p=0.00036), and cat dander (rho=0.130, p=0.0085). Furthermore, mean serum biotin levels in children with cedar pollinosis, but not with other allergic diseases such as asthma and allergic rhinitis, were significantly higher than in those without (p=0.0015). These results suggest a correlation between serum biotin levels and the development of cedar pollinosis. Further prospective studies are needed to evaluate the causal relationship between biotin metabolism and cedar pollen sensitization and pollinosis development.

Role of CC chemokine receptor 9 in the progression of murine and human non-alcoholic steatohepatitis.

BACKGROUND & AIMS: The number of patients with non-alcoholic steatohepatitis (NASH) is increasing globally. Recently, specific chemokine receptors have garnered interest as therapeutic targets in NASH. This is the first report to examine the role of the C-C chemokine receptor 9 (CCR9)/C-C chemokine receptor ligand 25 (CCL25) axis, and to reveal its therapeutic potential in NASH. METHODS: Patients with biopsy-proven non-alcoholic liver disease (NAFLD) were recruited and their serum and hepatic chemokine expression was examined. Furthermore, wild-type (WT) and Ccr9-/- mice were fed a high-fat high-cholesterol (HFHC) diet for 24 weeks to establish NASH. RESULTS: Serum CCL25, and hepatic CCR9 and CCL25 expression levels were increased in patients with NASH compared to healthy volunteers. Furthermore, Ccr9-/- mice were protected from HFHC diet-induced NASH progression both serologically and histologically. Flow cytometry and immunohistochemistry analysis showed that CCR9+CD11b+ inflammatory macrophages accumulated in the inflamed livers of HFHC diet-fed mice, while the number was reduced in Ccr9-/- mice. Consistent with human NASH livers, CCR9 was also expressed on hepatic stellate cells (HSCs) in mice with NASH, while CCR9-deficient HSCs showed less fibrogenic potential in vitro. Administration of a CCR9 antagonist hampered further fibrosis progression in mice with NASH, supporting its potential clinical application. Finally, we showed that CCR9 blockade attenuated the development of NAFLD-related hepatocellular carcinoma in HF diet-fed mice injected with diethylnitrosamine. CONCLUSIONS: These results highlight the role of the CCR9/CCL25 axis on macrophage recruitment and fibrosis formation in a murine NASH model, providing new insights into therapeutic strategies for NASH. LAY SUMMARY: Herein, we show that a specific chemokine axis involving a receptor (CCR9) and its ligand (CCL25) contributes to the progression of non-alcoholic steatohepatitis and carcinogenesis in humans and mice. Furthermore, treatment with a CCR9 antagonist ameliorates the development of steatohepatitis and holds promise for the treatment of patients with non-alcoholic steatohepatitis.

A training and education program for genome medical research coordinators in the genome cohort study of the Tohoku Medical Megabank Organization.

BACKGROUND: Genome cohort studies are used to analyze interactions between genetic and environmental factors, providing valuable information for personalized healthcare. Large-scale and long-term cohort studies require a number of specially trained personnel, of whom those involved in obtaining informed consent play a vital role, especially during the initial phase of such studies. The Japanese Society of Human Genetics (JSHG) previously established a certification system for genome medical research coordinators (GMRCs) responsible for obtaining written consent via face-to-face explanation. Meanwhile, in the Tohoku Medical Megabank Organization (ToMMo), GMRCs are expected to play important roles not only in obtaining informed consent and conducting various assessments, but also in communicating with participants throughout the long-term follow-up. Based on the JSHG program, we therefore developed a specific education and training program for ToMMo GMRCs consisting of 17 lectures, one practical training session on the informed consent procedure, and written and interview examinations. Re-education workshops aimed at self-improvement are also carried out following certification. In this study, we evaluated the education and training program in terms of overall understanding, usefulness, and satisfaction using an anonymous questionnaire. METHODS: An anonymous questionnaire addressing each aspect of the education and training program (understanding, usefulness, and satisfaction) was distributed among 152 qualified ToMMo GMRCs. Responses were received from 94 participants (61.8%). RESULTS: There was a significant association between the level of overall understanding of lectures and medical qualification (nurse or clinical laboratory technologist), but not with age or educational background. The level of understanding and overall usefulness were lower in sessions related to genetics and epidemiology than those dealing with ToMMo practices. In the re-education workshops, GMRCs showed a preference for and hoped to learn more about both background knowledge and research progress in the ToMMo. CONCLUSIONS: The results of our questionnaire suggest that not all ToMMo GMRCs are able to understand everything during the initial education and training program, especially in terms of genomic medicine. Continuous re-education is therefore vital in improving knowledge, skills and motivation, and preparing GMRCs for a specialist role in community-based personalized healthcare.

Intestinal epithelial cells promote secretion of leptin and adiponectin in adipocytes.

Although leptin and adiponectin are the predominant adipokines, how their circulating levels are regulated is incompletely understood. The present study tested whether intestinal epithelial cells influence the expression and secretion of these adipokines by adipocytes. Leptin gene expression and secretion by cultured human primary adipocytes and Simpson-Golabi-Behmel Syndrome adipocytes increased upon coculture with human enterocytic Caco-2 cells or incubation in conditioned medium of Caco-2 cells. Although adiponectin secretion increased, its mRNA levels decreased. Tissue homogenate of the ileum (but not the jejunum, colon, or liver) of nonobese C57BL/6J mice also stimulated leptin and adiponectin secretion by cultured murine 3T3-L1 adipocytes. However, ileal homogenate of obese KK-Ay mice had no effect on leptin and adiponectin secretion. We propose that as yet unidentified humoral factors released from intestinal epithelial cells are involved in regulating circulating leptin and adiponectin levels. Decreased production of such factors may contribute to hyperphagia in KK-Ay mice.