Stage III Chorioamnionitis is Associated with Reduced Risk of Severe Retinopathy of Prematurity.

OBJECTIVE: To identify whether histologically confirmed chorioamnionitis (hCAM) is associated with development of retinopathy of prematurity (ROP). STUDY DESIGN: We retrospectively analyzed 2 different cohorts. Cohort 1 was the national database of newborns in Japan born at ≤1500g or <32 weeks' gestation (January 2003 through April 2021, n = 38 013). Cohort 2 was babies born at <1500g from a single institution in Tsuchiura, Japan, (April 2015 through March 2018, n = 118). RESULTS: For Cohort1, after adjusting for potential confounders, stage III CAM (n = 5554) was associated with lower odds of severe ROP (stage ≥3 or required peripheral retinal ablation) by 14% (OR: 0.86; 95% CI: 0.78-0.94]. CAM of stage I (n = 3277) and II (n = 4319) was not associated with the risk of ROP. For Cohort 2, the odds of severe ROP were significantly reduced in moderate to severe hCAM groups (stage II, OR: 0.06, 95% CI: 0.05-0.82; stage III, OR: 0.10, 95% CI: 0.01-0.84). Neonates with funisitis, comorbidity of hCAM, and a finding of fetal inflammatory response had lower odds of severe ROP (OR: 0.11; 95% CI: 0.01-0.93). CONCLUSIONS: After adjusting for confounders, severe hCAM with fetal inflammatory response was associated with reduced risk of ROP.

Pluripotent stem cell models of Blau syndrome reveal an IFN-γ-dependent inflammatory response in macrophages.

BACKGROUND: Blau syndrome, or early-onset sarcoidosis, is a juvenile-onset systemic granulomatosis associated with a mutation in nucleotide-binding oligomerization domain 2 (NOD2). The underlying mechanisms of Blau syndrome leading to autoinflammation are still unclear, and there is currently no effective specific treatment for Blau syndrome. OBJECTIVES: To elucidate the mechanisms of autoinflammation in patients with Blau syndrome, we sought to clarify the relation between disease-associated mutant NOD2 and the inflammatory response in human samples. METHODS: Blau syndrome-specific induced pluripotent stem cell (iPSC) lines were established. The disease-associated NOD2 mutation of iPSCs was corrected by using a CRISPR-Cas9 system to precisely evaluate the in vitro phenotype of iPSC-derived cells. We also introduced the same NOD2 mutation into a control iPSC line. These isogenic iPSCs were then differentiated into monocytic cell lineages, and the statuses of nuclear factor κB pathway and proinflammatory cytokine secretion were investigated. RESULTS: IFN-γ acted as a priming signal through upregulation of NOD2. In iPSC-derived macrophages with mutant NOD2, IFN-γ treatment induced ligand-independent nuclear factor κB activation and proinflammatory cytokine production. RNA sequencing analysis revealed distinct transcriptional profiles of mutant macrophages both before and after IFN-γ treatment. Patient-derived macrophages demonstrated a similar IFN-γ-dependent inflammatory response. CONCLUSIONS: Our data support the significance of ligand-independent autoinflammation in the pathophysiology of Blau syndrome. Our comprehensive isogenic disease-specific iPSC panel provides a useful platform for probing therapeutic and diagnostic clues for the treatment of patients with Blau syndrome.

Single transcription factor efficiently leads human induced pluripotent stem cells to functional microglia.

BACKGROUND: Microglia are innate immune cells that are the only residential macrophages in the central nervous system. They play vital physiological roles in the adult brain and during development. Microglia are particularly in the spotlight because many genetic risk factors recently identified for neurodegenerative diseases are largely expressed in microglia. Rare polymorphisms in these risk alleles lead to abnormal activity of microglia under traumatic or disease conditions. METHODS: In the present study, to investigate the multifaceted functions of human microglia, we established a novel robust protocol to generate microglia from human induced pluripotent stem cells (hiPSCs) using a combination of cytokines and small chemicals essential for microglia ontogeny. Moreover, we highly enhanced the microglial differentiation efficiency by forcing the expression of PU.1, a crucial transcription factor for microglial development, during posterior mesoderm differentiation. RESULTS: By our novel method, we demonstrated the generation of a greater number of hiPSC-derived microglia (hiMGLs, approximately 120-folds) than the prior methods (at most 40-folds). Over 90% of the hiMGLs expressed microglia-specific markers, such as CX3CR1 and IBA-1. Whole-transcriptome analysis revealed that these hiMGLs are similar to human primary microglia but differ from monocytes/macrophages. Furthermore, the specific physiological functions of microglia were confirmed through indices of lipopolysaccharide responsiveness, phagocytotic ability, and inflammasome formation. By co-culturing these hiMGLs with mouse primary neurons, we demonstrated that hiMGLs can regulate the activity and maturation of neurons. CONCLUSIONS: In this study, our new simple, rapid, and highly efficient method for generating microglia from hiPSCs will prove useful for future investigations on microglia in both physiological and disease conditions, as well as for drug discovery.

Pluripotent stem cell-based screening identifies CUDC-907 as an effective compound for restoring the in vitro phenotype of Nakajo-Nishimura syndrome.

Nakajo-Nishimura syndrome (NNS) is an autoinflammatory disorder caused by a homozygous mutations in the PSMB8 gene. The administration of systemic corticosteroids is partially effective, but continuous treatment causes severe side effects. We previously established a pluripotent stem cell (PSC)-derived NNS disease model that reproduces several inflammatory phenotypes, including the overproduction of monocyte chemoattractant protein-1 (MCP-1) and interferon gamma-induced protein-10 (IP-10). Here we performed high-throughput compound screening (HTS) using this PSC-derived NNS model to find potential therapeutic candidates and identified CUDC-907 as an effective inhibitor of the release of MCP-1 and IP-10. Short-term treatment of CUDC-907 did not induce cell death within therapeutic concentrations and was also effective on primary patient cells. Further analysis indicated that the inhibitory effect was post-transcriptional. These findings suggest that HTS with PSC-derived disease models is useful for finding drug candidates for autoinflammatory diseases.

Induced pluripotent stem cells representing Nakajo-Nishimura syndrome.

Nakajo-Nishimura syndrome is a proteasome-associated autoinflammatory syndrome with a distinct homozygous mutation in the PSMB8 gene encoding an inducible ß5i subunit of the immunoproteasome. Although it is considered that immunoproteasome dysfunction causes cellular stress and contributes to the production of inflammatory cytokines and chemokines, its detailed mechanism is still unknown. On the other hand, hereditary autoinflammatory diseases are considered as a good target for the analyses using induced pluripotent stem cells, whose differentiation systems to the innate immune cells such as neutrophils and monocytes have been established. Therefore, to elucidate the pathogenesis of Nakajo-Nishimura syndrome, we attempted in vitro disease modeling using patient-derived induced pluripotent stem cells. For analyses, isogenic control cells in which the responsible mutation was repaired and another pair of healthy embryonic stem cells and isogenic mutant cells in which the same mutation was introduced had also been prepared with genetic engineering. By comparing a pair of isogenic cells with the wild-type and the mutant PSMB8 gene after differentiation into monocytes and immortalization to synchronize their differentiation stages, the reduction of immunoproteasome enzyme activity and increased cytokine and chemokine production in the mutant cells without stimulation or with interferon-γ plus tumor necrosis factor-α stimulation were observed, and therefore, the autoinflammatory phenotype was successfully reproduced. Decreased cytokine production was observed by the addition of antioxidants as well as inhibitors for Janus kinase and p38-mitogen-activated protein kinase. At the same time, the increased production of reactive oxygen species and phosphorylation of both signal transducers and activator of transcription 1 and p38-mitogen-activated protein kinase were detected without stimulation. Notably, an antioxidant specifically decreased the constitutive phosphorylation of signal transducers and activator of transcription 1. These results indicate the usefulness of a disease modeling using pluripotent stem cell-derived cells in clarification of the pathomechanism and discovery of new therapeutic drugs for Nakajo-Nishimura syndrome and related proteasome-associated autoinflammatory syndromes.

Pluripotent Stem Cell Model of Nakajo-Nishimura Syndrome Untangles Proinflammatory Pathways Mediated by Oxidative Stress.

Nakajo-Nishimura syndrome (NNS) is an immunoproteasome-associated autoinflammatory disorder caused by a mutation of the PSMB8 gene. Although dysfunction of the immunoproteasome causes various cellular stresses attributed to the overproduction of inflammatory cytokines and chemokines in NNS, the underlying mechanisms of the autoinflammation are still largely unknown. To investigate and understand the mechanisms and signal pathways in NNS, we established a panel of isogenic pluripotent stem cell (PSC) lines with PSMB8 mutation. Activity of the immunoproteasome in PSMB8-mutant PSC-derived myeloid cell lines (MT-MLs) was reduced even without stimulation compared with non-mutant-MLs. In addition, MT-MLs showed an overproduction of inflammatory cytokines and chemokines, with elevated reactive oxygen species (ROS) and phosphorylated p38 MAPK levels. Treatment with p38 MAPK inhibitor and antioxidants decreased the abnormal production of cytokines and chemokines. The current PSC model revealed a specific ROS-mediated inflammatory pathway, providing a platform for the discovery of alternative therapeutic options for NNS and related immunoproteasome disorders.

Robust and highly-efficient differentiation of functional monocytic cells from human pluripotent stem cells under serum- and feeder cell-free conditions.

Monocytic lineage cells (monocytes, macrophages and dendritic cells) play important roles in immune responses and are involved in various pathological conditions. The development of monocytic cells from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) is of particular interest because it provides an unlimited cell source for clinical application and basic research on disease pathology. Although the methods for monocytic cell differentiation from ESCs/iPSCs using embryonic body or feeder co-culture systems have already been established, these methods depend on the use of xenogeneic materials and, therefore, have a relatively poor-reproducibility. Here, we established a robust and highly-efficient method to differentiate functional monocytic cells from ESCs/iPSCs under serum- and feeder cell-free conditions. This method produced 1.3 × 10(6) ± 0.3 × 10(6) floating monocytes from approximately 30 clusters of ESCs/iPSCs 5-6 times per course of differentiation. Such monocytes could be differentiated into functional macrophages and dendritic cells. This method should be useful for regenerative medicine, disease-specific iPSC studies and drug discovery.