Sin-Hyeog Im

Pohang University of Sciences and Biotechnology & ImmunoBiome Inc. · Life Sciences

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease that mainly affects women in their reproductive years. A complex interaction of environmental and genetic factors leads to the disruption of immune tolerance towards self, causing overt immune activation and production of autoantibodies that attack multiple organs. Kidney damage, te...

Multifaceted functions displayed by both pro‐ and anti‐inflammatory properties of chitosan hinder its effective development as an immunomodulatory agent. Herein, the contributions of the bending stiffness of chitosan with regard to its immune regulatory properties toward inflammation are investigated. The anti‐inflammatory properties of chitosan mo...

Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in the nicotinamide adenine dinucleotide (NAD⁺) salvage pathway and plays a crucial role in the maintenance of the NAD⁺ pool during inflammation. Considering that macrophages are essential for tissue homeostasis and inflammation, we sought to examine the functional impact of...

Background and Objectives Wound healing is an important biomedical problem with various associated complications. Although cutaneous wound healing has been studied in vivo extensively using various optical imaging methods, early-stage cellular healing processes were difficult to study due to scab formation. The objective of this study is to demonst...

Yeast is an integral part of mammalian microbiome, and like commensal bacteria, has the potential of being harnessed to influence immunity in clinical settings. However, functional specificities of yeast-derived immunoregulatory molecules remain elusive. Here we find that while under steady state, β-1,3-glucan-containing polysaccharides potentiate...

The intestine harbors a complex community of bacterial species collectively known as commensal microbiota. Specific species of resident bacteria, as known as pathobiont, have pathogenic potential and can induce apparent damage to the host and intestinal inflammation in a certain condition. However, the host immune factors that permit its commensali...

Retinoic acid‐related orphan receptor γ (RORγ) maintains the circadian rhythms of its downstream genes. However, the mechanism behind the transcriptional activation of RORγ itself remains unclear. Here, we demonstrate that transcription of RORγ is activated by heterogeneous nuclear ribonucleoprotein K (hnRNP K) via the poly(C) motif within its prox...

Particulate matter (PM) induces neutrophilic inflammation and deteriorates the prognosis of diseases such as cardiovascular diseases, cancers, and infections, including COVID-19. Here, we addressed the role of γδ T cells and intestinal microbiome in PM-induced acute neutrophilia. γδ T cells are a heterogeneous population composed of Tγδ1, Tγδ2, Tγδ...

Objective To investigate the clinical effects of IRT5 probiotics in the environmental dry eye model. Methods Eight week old male C57BL/6 mice were randomly divided into two groups; control group (n = 16) received oral gavage of 300 μL phosphate-buffered saline (PBS) alone once daily, IRT5 group (n = 9) received oral gavage of 1 x 10 ⁹ CFU IRT5 pro...

Considerable evidence points to the critical role of the gut microbiota in physiology and disease. The administration of live microbes as a therapeutic modality is increasingly being considered. However, key questions such as how to identify candidate microorganisms and which preclinical models are relevant to recapitulate human microbiota remain l...

Type 1 autoimmune diabetes is an autoimmune disease characterized by specific destruction of pancreatic β-cells producing insulin. Recent studies have shown that gut microbiota and immunity are closely linked to systemic immunity, affecting the balance between pro-inflammatory and regulatory immune responses. Altered gut microbiota may be causally...

Retinal dehydrogenase (RALDH) enzymatic activities catalyze the conversion of vitamin A to its metabolite Retinoic acid (RA) in intestinal dendritic cells (DCs) and promote immunological tolerance. However, precise understanding of the exogenous factors that act as initial trigger of RALDH activity in these cells is still evolving. By using germ-fr...

ETS1 has shown dichotomous roles as an oncogene and a tumor suppressor gene in diverse cancers, but its functionality in breast cancer tumorigenesis still remains unclear. We utilized the Cancer Genome Atlas (TCGA) database to analyze comprehensive functions of ETS1 in human breast cancer (BRCA) patients by investigating its expression patterns and...

Intestinal microbiota impacts the host immune system and influences the outcomes of chronic diseases. However, it remains uncertain whether acute kidney injury (AKI) impacts intestinal microbiota or vice versa. To determine this, we investigated the mechanistic link between AKI, microbiota, and immune response in ischemia/reperfusion injury. Microb...

The capsular material from Lactobacillus plantarum IMB19, an isolate from fermented vegetables, has been analyzed and our results demonstrate that most of the coat of this bacterium consists of glycerol- and ribitol-type teichoic acids, further decorated with other substituents (α-glucose and alanine), and of a capsular polysaccharide (CPS) with a...

Purpose: While the association between the gut microbiome and the immune system has been studied in autoimmune disorders, little is known about ocular disease. Previously we reported that IRT5, a mixture of five probiotic strains, could suppress autoimmune dry eye. In this study, we investigated the mechanism by which IRT5 performs its immunomodul...

ABSTRACT Several gut commensals have been shown to modulate host immune response. Recently, many food derived microbes have also been reported to affect the immune system. However, a mechanism to identify immunostimulatory and immunoregulatory microbes is needed. Here, we successfully established an in vitro screening system and identified an immun...

Following publication of the original article [1], the authors have re-evaluated the authorship for this article. The updated author group is.

IL-2 is a pleiotropic cytokine that plays an essential role in the survival, expansion, and function of CD8 T cells, regulatory T cells (Tregs), and natural killer (NK) cells. Previous studies showed that binding IL-2 with an anti-IL-2 monoclonal antibody (mAb) with a particular specificity could block its interaction with IL-2Rα, which is mainly e...

The microbiota regulate hematopoiesis in the bone marrow (BM); however, the detailed mechanisms remain largely unknown. In this study, we explored how microbiota-derived molecules (MDMs) were transferred to the BM and sensed by the local immune cells to control hematopoiesis under steady-state conditions. We reveal that MDMs, including bacterial DN...

Foxp3 and its protein partners establish a regulatory T (T reg ) cell transcription profile and promote immunological tolerance. However, molecular features contributing to a T reg -specific gene expression program are still incompletely understood. We find that the transcription factor Bcl11b is a prominent Foxp3 cofactor with multifaceted functio...

The chemical structure of cell surface polysaccharides isolated from Bifidobacterium bifidum strain PRI1, an important member of the gut microbiota of breast-fed infants, has been elucidated by chemical and NMR spectroscopy analysis. Results demonstrated that the bacterium produces a complex mixture of polysaccharides that could be classified in tw...

Atopic dermatitis (AD) is a complex inflammatory skin disease mediated by immune cells of both adaptive and innate types. Among them, CD4+ Th cells are one of major players of AD pathogenesis. Although the pathogenic role of Th2 cells has been well characterized, Th17/Th22 cells are also implicated in the pathogenesis of AD. However, the molecular...

Single-nucleotide polymorphisms in ETS1 are associated with systemic lupus erythematosus (SLE). Ets1−/− mice develop SLE-like symptoms, suggesting that dysregulation of this transcription factor is important to the onset or progression of SLE. We used conditional deletion approaches to examine the impact of Ets1 expression in different immune cell...

Abstract Breast cancer is highly aggressive and is the leading cause of cancer-related mortality in women in developed countries. The ETS proto-oncogene 1 (Ets1) has versatile roles during the cellular processes of cancer development. It is often highly expressed in breast cancers and mediates migration and invasion of human breast cancer cells. Ho...

TH17 cells originating from regulatory T (Treg) cells upon loss of the Treg-specific transcription factor Foxp3 accumulate in sites of inflammation and aggravate autoimmune diseases. Whether an active mechanism drives the generation of these pathogenic ‘ex-Foxp3 TH17’ cells, remains unclear. Here we show that pro-inflammatory cytokines enhance the...

The prevalence of allergic disorders has dramatically increased over the past decade, particularly in developed countries. Apart from gastrointestinal disorders, neoplasia, genital and dermatological diseases etc., dysregulation of gut microbiota (dysbiosis) has also been found to be associated with increased risk of allergies. Probiotics are incre...

Regulatory T (Treg) cells, which are broadly classified as thymically derived (tTreg) or extrathymically induced (iTreg), suppress immune responses and display stringent dependence to the transcription factor Foxp3. However precise understanding of molecular events that promote and preserve Foxp3 expression in Treg cells is still evolving. Here we...

Dysregulation of intestinal microflora is linked to inflammatory disorders associated with compromised immunosuppressive functions of Foxp3 ⁺ T regulatory (T reg ) cells. Although mucosa-associated commensal microbiota has been implicated in T reg generation, molecular identities of the “effector” components controlling this process remain largely...

Paneth cells are one of the principal epithelial cell types in the small intestine, located at the base of intestinal crypts. Paneth cells play key roles in intestinal host-microbe homeostasis via granule secretion, and their dysfunction is implicated in pathogenesis of several diseases including Crohn's disease. Despite their physiological importa...

Microvilli on T cells have been proposed to survey surfaces of antigen-presenting cells (APC) or facilitate adhesion under flow; however, whether they serve essential functions during T cell activation remains unclear. Here we show that antigen-specific T cells deposit membrane particles derived from microvilli onto the surface of cognate antigen-b...

The fast and intense proliferative responses have been well documented for naïve T cells adoptively transferred into chronic lymphopenic hosts. This response known as spontaneous proliferation (SP), unlike antigen-independent lymphopenia-induced proliferation (LIP), is driven in a manner dependent on antigens derived from commensal microbiota. Howe...

Inflammatory bowel disease (IBD) is a chronic inflammatory disease where the intestinal epithelium loses its barrier function. Given the existence of the oxygen gradient in the intestinal epithelium and that inflammation further contributes to the tissue hypoxia, we investigated a role of hypoxia-inducible factor (HIF), a transcription factor activ...

Inflammatory bowel disease (IBD), encompassing ulcerative colitis and Crohn's disease, is a multifactorial inflammatory disease of the small intestine and colon. Many investigators have reported that l-glutamine (Gln) therapy improves outcomes of experimental colitis models, although the mechanism is not fully understood. Regarding the anti-inflamm...

Many itch mediators activate G-protein coupled receptor (GPCR), and trigger itch via activation of GPCR-mediated signaling pathways. GPCRs are desensitized by G protein-coupled receptor kinases (GRKs). The aim of this study is to explore the role of GRKs in itch response and the linkage between GRKs and glutamine (Gln), an amino acid previously dem...