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71 result(s) for "Jong-Ik Hwang"
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Deficiency of Ninjurin1 attenuates LPS/D‐galactosamine‐induced acute liver failure by reducing TNF‐α‐induced apoptosis in hepatocytes
Nerve injury‐induced protein 1 (Ninjurin1, Ninj1) is a membrane protein that mediates cell adhesion. The role of Ninj1 during inflammatory response has been widely investigated in macrophages and endothelial cells. Ninj1 is expressed in various tissues, and the liver also expresses high levels of Ninj1. Although the hepatic upregulation of Ninj1 has been reported in human hepatocellular carcinoma and septic mice, little is known of its function during the pathogenesis of liver diseases. In the present study, the role of Ninj1 in liver inflammation was explored using lipopolysaccharide (LPS)/D‐galactosamine (D‐gal)‐induced acute liver failure (ALF) model. When treated with LPS/D‐gal, conventional Ninj1 knock‐out (KO) mice exhibited a mild inflammatory phenotype as compared with wild‐type (WT) mice. Unexpectedly, myeloid‐specific Ninj1 KO mice showed no attenuation of LPS/D‐gal‐induced liver injury. Whereas, Ninj1 KO primary hepatocytes were relatively insensitive to TNF‐α‐induced caspase activation as compared with WT primary hepatocytes. Also, Ninj1 knock‐down in L929 and AML12 cells and Ninj1 KO in HepG2 cells ameliorated TNF‐α‐mediated apoptosis. Consistent with in vitro results, hepatocyte‐specific ablation of Ninj1 in mice alleviated LPS/D‐gal‐induced ALF. Summarizing, our in vivo and in vitro studies show that lack of Ninj1 in hepatocytes diminishes LPS/D‐gal‐induced ALF by alleviating TNF‐α/TNFR1‐induced cell death.
Partial FAM19A5 deficiency in mice leads to disrupted spine maturation, hyperactivity, and an altered fear response
The FAM19A5 polypeptide, encoded by the TAFA5 gene, is evolutionarily conserved among vertebral species. This protein is predominantly expressed in the brain, highlighting its crucial role in the central nervous system. Here, we investigated the potential roles of FAM19A5 in brain development and behavior using a FAM19A5-LacZ KI mouse model. This model exhibited a partial reduction in the FAM19A5 protein level. FAM19A5-LacZ KI mice displayed no significant alterations in gross brain structure but alterations in dendritic spine distribution, with a bias toward immature forms. These mice also had lower body weights. Behavioral tests revealed that compared with their wild-type littermates, FAM19A5-LacZ KI male mice displayed hyperactivity and a delayed innate fear response. These findings suggest that FAM19A5 plays a role in regulating spine maturation and maintenance, thereby contributing to neural connectivity and behavior.
Exploring neurokinin-1 receptor antagonism for depression with structurally differentiated inhibitors
The neurokinin-1 receptor (NK1R) has been investigated as a potential target for major depressive disorder owing to its role in stress regulation and neuroinflammation. However, clinical trials of NK1R antagonists have yielded inconsistent results, leaving it unclear whether these outcomes reflect limitations of NK1R as a therapeutic target or shortcomings inherent to the clinical candidates tested. The majority of previously developed NK1R antagonists contain a 3,5-bis-trifluoromethylphenyl moiety, which enhances receptor binding but may also influence drug metabolism, pharmacokinetics or receptor interactions, potentially affecting therapeutic efficacy. Whether structurally distinct NK1R antagonists exhibit different antidepressant potential remains an open question. Here we used computational approaches to identify NK1R antagonists lacking the 3,5-bis-trifluoromethylphenyl group and evaluated their effects in preclinical models of depression. Several compounds exhibited NK1R antagonistic activity and reduced depressive-like behaviors, with compound #15 demonstrating the most pronounced effects. Molecular docking and molecular dynamics simulations revealed a distinct binding mode for compound #15, characterized by a hydrogen bond interaction with Asn109 and π–π stacking with His197, suggesting structural differences that may influence NK1R modulation. These findings support the potential of structurally diverse NK1R antagonists to modulate behavior and neuroinflammatory responses in preclinical models. While the relevance of these structural differences to clinical outcomes remains to be determined, our results provide a preliminary framework for further investigation of chemically novel NK1R antagonists in the context of major depressive disorder.
Ninjurin1 Plays a Crucial Role in Pulmonary Fibrosis by Promoting Interaction between Macrophages and Alveolar Epithelial Cells
The transmembrane nerve injury-induced protein 1 (Ninjurin1 or Ninj1) is involved in progressing inflammatory diseases. In this study, we aimed to investigate a novel function of Ninj1 in pulmonary fibrosis. We found that the expression of Ninj1 in a patient cohort was upregulated in the lung specimens of idiopathic pulmonary fibrosis patients as well as mice with bleomycin-induced pulmonary fibrosis. In addition, the BLM-injected Ninj1 KO mice exhibited a mild fibrotic phenotype, as compared to WT mice. Therefore, we hypothesized that Ninj1 would play an important role in the development of pulmonary fibrosis. We discovered that Ninj1 expression increased in BLM-treated macrophages and alveolar epithelial cells (AECs). Interestingly, macrophages bound to BLM-treated AECs were activated. However, when Ninj1 expression was suppressed in either of AECs or macrophages, contact-dependent activation of macrophages with AECs was diminished. In addition, introduction of recombinant mouse Ninj1 1–50 to macrophages triggered an inflammatory response, but did not stimulate Ninj1-deficient macrophages. In conclusion, we propose that Ninj1 may contribute to activation of macrophages by enhancing interaction with AECs having elevated Ninj1 expression due to injury-inducing stimuli. Consequently, Ninj1 may be involved in the development of pulmonary fibrosis by enhancing inflammatory response of macrophages.
Identification of chemical scaffolds for targeting ubiquitin-specific protease 11 (USP11) through high-throughput virtual screening
USP11 is a promising therapeutic target implicated in Alzheimer's disease and various cancers; however, no specific inhibitors are currently available, with the only known inhibitor being mitoxantrone, which primarily targets topoisomerase II. To identify novel chemical starting points, we conducted high-throughput virtual screening using a USP11 homology model. Screening over 600,000 compounds yielded five structurally distinct hits with significant inhibitory activity. Biochemical validation highlighted two promising scaffolds: benzoxadiazole derivatives and pyrrolo-phenylamidine analogues, both demonstrating structure-dependent inhibition and tractable SAR profiles. Docking studies further characterised their binding modes, supporting their potential for optimisation. Hydroxyphenyl hydrazone analogues raised PAINS-related concerns, while compounds such as squalamine were deprioritized due to weak binding affinity and structural complexity. Overall, this study provides valuable scaffolds and mechanistic insights that can inform future development of potent, selective USP11 inhibitors.
Development of Spexin-based Human Galanin Receptor Type II-Specific Agonists with Increased Stability in Serum and Anxiolytic Effect in Mice
The novel neuropeptide spexin (SPX) was discovered to activate galanin receptor 2 (GALR2) and 3 (GALR3) but not galanin receptor 1 (GALR1). Although GALR2 is known to display a function, particularly in anxiety, depression, and appetite regulation, the further determination of its function would benefit from a more stable and selective agonist that acts only at GALR2. In the present study, we developed a GALR2-specific agonist with increased stability in serum. As galanin (GAL) showed a low affinity to GALR3, the residues in SPX were replaced with those in GAL, revealing that particular mutations such as Gln5 → Asn, Met7 → Ala, Lys11 → Phe, and Ala13 → Pro significantly decreased potencies toward GALR3 but not toward GALR2. Quadruple (Qu) mutation of these residues still retained potency to GALR2 but totally abolished the potency to both GALR3 and GALR1. The first amino acid modifications or D-Asn1 substitution significantly increased the stability when they are incubated in 100% fetal bovine serum. Intracerebroventricular administration of the mutant peptide with D-Asn1 and quadruple substitution (dN1-Qu) exhibited an anxiolytic effect in mice. Taken together, the GALR2-specific agonist with increased stability can greatly help delineation of GALR2-mediated functions and be very useful for treatments of anxiety disorder.
SP-8356, a (1S)-(–)-verbenone derivative, exerts in vitro and in vivo anti-breast cancer effects by inhibiting NF-κB signaling
Breast cancer exhibits high lethality in women because it is frequently detected at an advanced stage and aggressive forms such as triple-negative breast cancer (TNBC), which are often characterized by metastasis through colonization of secondary tumors. Thus, developing therapeutic agents that target the metastatic process is crucial to successfully treat aggressive breast cancer. We evaluated SP-8356, an anti-inflammatory synthetic verbenone derivative, with respect to its regulation of breast cancer cell behavior and cancer progression. Treatment of SP-8356 arrested cell cycle and reduced growth in various types of breast cancer cells with mild cytotoxicity. Particularly, SP-8356 significantly reduced the motility and invasiveness of TNBC cells. Assays using an in vivo xenograft mouse model confirmed the cell-specific anti-proliferative and anti-metastatic activity of SP-8356. Functional studies revealed that SP-8356 suppressed serum response element-dependent reporter gene expression and NF-κB-related signaling, resulting in downregulation of many genes related to cancer invasion. We conclude that SP-8356 suppresses breast cancer progression through multimodal functions, including inhibition of NF-κB signaling and growth-related signaling pathways.
LMT2368 (1-(4-Chlorophenyl)-3-(3-fluoro-5-(trifluoromethyl)phenyl)urea) Negatively Regulates Inflammation by Inhibiting NLRP3 Inflammasome Activation
Background/Objectives: The dysregulation of NLRP3 inflammasome activation has been established as a key driver of inflammatory disease pathology, which marks NLRP3 as an attractive therapeutic target. However, the clinical development of NLRP3 inhibitors such as MCC950 has been hampered by their associated toxicity profiles, highlighting an unmet clinical need. Methods: Herein, we present LMT2368, a novel urea-based NLRP3 inhibitor identified through screening of urea-based derivatives from our in-house compound library. Results: Biolayer interferometry confirmed direct binding of LMT2368 to the NLRP3 NACHT domain with a (KD = 27.4 ± 1.2 μM which was superior to MCC950. Molecular docking studies predicted enhanced binding interactions for LMT2368, consistent with its improved biological activity. In LPS-primed macrophages, LMT2368 dose-dependently suppressed IL-1β secretion (IC50 = 0.8 μM in J774A.1 cells) and caspase-1 activation without affecting NF-κB signaling. Importantly, LMT2368 inhibited ASC oligomerization and pyroptosis while maintaining excellent safety margins (CC50 > 50 μM). In a murine model of LPS-induced acute lung injury, LMT2368 (10 mg/kg) reduced bronchoalveolar lavage fluid immune cell infiltration by 68% (p < 0.001), suppressed pro-inflammatory cytokine release (IL-1β/IL-6/TNF-α), and preserved lung histoarchitecture. Notably, LMT2368 showed selectivity for NLRP3 inhibition without affecting TNF-α/IL-6 production during TLR4 priming in monocytic cell lines. Conclusions: Together, these findings establish LMT2368 as a promising lead compound for developing safer NLRP3 inhibitors with therapeutic potential for inflammasome-driven diseases.
The N-terminus of CXCR4 splice variants determines expression and functional properties
C-X-C motif chemokine ligand 12(CXCL12) is an essential chemokine for organ development and homeostasis in multiple tissues. Its receptor, C-X-C chemokine receptor type 4(CXCR4), is expressed on the surface of target cells. The chemokine and receptor are expressed almost ubiquitously in human tissues and cells throughout life, and abnormal expression of CXCL12 and CXCR4 is observed in pathological conditions, such as inflammation and cancer. CXCR4 is reportedly translated into five splicing variants of different lengths, which each have different amino acids in the N-terminus. As the N-terminus is the first recognition site for chemokines, CXCR4 variants may respond differently to CXCL12. Despite these differences, the molecular and functional properties of CXCR4 variants have not been thoroughly described or compared. Here, we explored the expression of CXCR4 variants in cell lines and analyzed their roles in cellular responses using biochemical approaches. RT-PCR revealed that most cell lines express more than one CXCR4 variant. When expressed in HEK293 cells, the CXCR4 variants differed in protein expression efficiency and cell surface localization. Although variant 2 demonstrated the strongest expression and cell surface localization, variants 1, 3, and 5 also mediated chemokine signaling and induced cellular responses. Our results demonstrate that the N-terminal sequences of each CXCR4 variant determine the expression of the receptor and affect ligand recognition. Functional analyses revealed that CXCR4 variants may also affect each other or interact during CXCL12-stimulated cellular responses. Altogether, our results suggest that CXCR4 variants may have distinct functional roles that warrant additional investigation and could contribute to future development of novel drug interventions.
The unique expression profile of FAM19A1 in the mouse brain and its association with hyperactivity, long-term memory and fear acquisition
Neurodevelopment and mature brain function are spatiotemporally regulated by various cytokines and chemokines. The chemokine-like neuropeptide FAM19A1 is a member of family with sequence similarity 19 (FAM19), which is predominantly expressed in the brain. Its highly conserved amino acid sequence among vertebrates suggests that FAM19A1 may play important physiological roles in neurodevelopment and brain function. Here we used a LacZ reporter gene system to map the expression pattern of the FAM19A1 gene in the mouse brain. The FAM19A1 expression was observed in several brain regions starting during embryonic brain development. As the brain matured, the FAM19A1 expression was detected in the pyramidal cells of cortical layers 2/3 and 5 and in several limbic areas, including the hippocampus and the amygdala. FAM19A1-deficient mice were used to evaluate the physiological contribution of FAM19A1 to various brain functions. In behavior analysis, FAM19A1-deficient mice exhibited several abnormal behaviors, including hyperactive locomotor behavior, long-term memory deficits and fear acquisition failure. These findings provide insight into the potential contributions of FAM19A1 to neurodevelopment and mature brain function.