IU Indianapolis ScholarWorks :: Browsing by Author "Cheon, In Su"

Browsing by Author "Cheon, In Su"

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BCL6 represses antiviral resistance in follicular T helper cells
(Wiley, 2017-08) Amet, Tohti; Son, Young Min; Jiang, Li; Cheon, In Su; Huang, Su; Gupta, Samir K.; Dent, Alexander L.; Montaner, Luis J.; Yu, Qigui; Sun, Jie; Microbiology and Immunology, School of Medicine
Follicular Th (Tfh) cells are a distinct subset of Th cells that help B cells produce class-switched antibodies. Studies have demonstrated that Tfh cells are highly prone to HIV infection and replication. However, the molecular mechanisms underlying this phenomenon are largely unclear. Here, we show that murine and human Tfh cells have diminished constitutive expression of IFN-stimulated genes (ISGs) inclusive of antiviral resistance factor MX dynamin-like GTPase 2 (MX2) and IFN-induced transmembrane 3 (IFITM3) compared with non-Tfh cells. A lower antiviral resistance in Tfh was consistent with a higher susceptibility to retroviral infections. Mechanistically, we found that BCL6, a master regulator of Tfh cell development, binds to ISG loci and inhibits the expression of MX2 and IFITM3 in Tfh cells. We demonstrate further that inhibition of the BCL6 BR-C, ttk, and bab (BTB) domain function increases the expression of ISGs and suppresses HIV infection and replication in Tfh cells. Our data reveal a regulatory role of BCL6 in inhibiting antiviral resistance factors in Tfh cells, thereby promoting the susceptibility Tfh cells to viral infections. Our results indicate that the modulation of BCL6 function in Tfh cells could be a potential strategy to enhance Tfh cell resistance to retroviral infections and potentially decrease cellular reservoirs of HIV infection.
Inhibition of stearoyl-CoA desaturases suppresses follicular help T- and germinal center B- cell responses
(Wiley, 2020-07) Son, Young Min; Cheon, In Su; Goplen, Nick P.; Dent, Alexander L.; Sun, Jie; Microbiology and Immunology, School of Medicine
Stearoyl-CoA desaturases (SCD) are endoplasmic reticulum (ER)-associated enzymes that catalyze the synthesis of the monounsaturated fatty acids (MUFAs). As such, SCD play important roles in maintaining the intracellular balance between saturated fatty acid (SFAs) and MUFAs. The roles of SCD in CD4+ T-helper cell responses are currently unexplored. Here, we have found that murine and human follicular helper T (TFH ) cells express higher levels of SCD compared to non-TFH cells. Further, the expression of SCD in TFH cells is dependent on the TFH lineage-specification transcription factor BCL6. We found that the inhibition of SCD impaired TFH cell maintenance and shifted the balance between TFH and follicular regulatory T (TFR ) cells in the spleen. Consequently, SCD inhibition dampened germinal center B-cell responses following influenza immunization. Mechanistically, we found that SCD inhibition led to increased ER stress and enhanced TFH cell apoptosis in vitro and in vivo. These results reveal a possible link between fatty acid metabolism and cellular and humoral responses induced by immunization or potentially, autoimmunity.
Inhibition of the mitochondrial pyruvate carrier simultaneously mitigates hyperinflammation and hyperglycemia in COVID-19
(American Association for the Advancement of Science, 2023) Zhu, Bibo; Wei, Xiaoqin; Narasimhan, Harish; Qian, Wei; Zhang, Ruixuan; Cheon, In Su; Wu, Yue; Li, Chaofan; Jones, Russell G.; Kaplan, Mark H.; Vassallo, Robert A.; Braciale, Thomas J.; Somerville, Lindsay; Colca, Jerry R.; Pandey, Akhilesh; Jackson, Patrick E. H.; Mann, Barbara J.; Krawczyk, Connie M.; Sturek, Jeffrey M.; Sun, Jie; Microbiology and Immunology, School of Medicine
The relationship between diabetes and coronavirus disease 2019 (COVID-19) is bidirectional: Although individuals with diabetes and high blood glucose (hyperglycemia) are predisposed to severe COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can also cause hyperglycemia and exacerbate underlying metabolic syndrome. Therefore, interventions capable of breaking the network of SARS-CoV-2 infection, hyperglycemia, and hyperinflammation, all factors that drive COVID-19 pathophysiology, are urgently needed. Here, we show that genetic ablation or pharmacological inhibition of mitochondrial pyruvate carrier (MPC) attenuates severe disease after influenza or SARS-CoV-2 pneumonia. MPC inhibition using a second-generation insulin sensitizer, MSDC-0602K (MSDC), dampened pulmonary inflammation and promoted lung recovery while concurrently reducing blood glucose levels and hyperlipidemia after viral pneumonia in obese mice. Mechanistically, MPC inhibition enhanced mitochondrial fitness and destabilized hypoxia-inducible factor-1α, leading to dampened virus-induced inflammatory responses in both murine and human lung macrophages. We further showed that MSDC enhanced responses to nirmatrelvir (the antiviral component of Paxlovid) to provide high levels of protection against severe host disease development after SARS-CoV-2 infection and suppressed cellular inflammation in human COVID-19 lung autopsies, demonstrating its translational potential for treating severe COVID-19. Collectively, we uncover a metabolic pathway that simultaneously modulates pulmonary inflammation, tissue recovery, and host metabolic health, presenting a synergistic therapeutic strategy to treat severe COVID-19, particularly in patients with underlying metabolic disease.
Neonatal hyperoxia promotes asthma-like features through IL-33–dependent ILC2 responses
(Elsevier, 2017) Cheon, In Su; Son, Young Min; Jiang, Li; Goplen, Nicholas P.; Kaplan, Mark H.; Limper, Andrew H.; Kita, Hirohito; Paczesny, Sophie; Prakash, Y. S.; Tepper, Robert; Ahlfeld, Shawn K.; Sun, Jie; Pediatrics, School of Medicine
Background Premature infants often require oxygen supplementation and, therefore, are exposed to oxidative stress. Following oxygen exposure, preterm infants frequently develop chronic lung disease and have a significantly increased risk of asthma. Objective We sought to identify the underlying mechanisms by which neonatal hyperoxia promotes asthma development. Methods Mice were exposed to neonatal hyperoxia followed by a period of room air recovery. A group of mice was also intranasally exposed to house dust mite antigen. Assessments were performed at various time points for evaluation of airway hyperresponsiveness, eosinophilia, mucus production, inflammatory gene expression, and TH and group 2 innate lymphoid cell (ILC2) responses. Sera from term- and preterm-born infants were also collected and levels of IL-33 and type 2 cytokines were measured. Results Neonatal hyperoxia induced asthma-like features including airway hyperresponsiveness, mucus hyperplasia, airway eosinophilia, and type 2 pulmonary inflammation. In addition, neonatal hyperoxia promoted allergic TH responses to house dust mite exposure. Elevated IL-33 levels and ILC2 responses were observed in the lungs most likely due to oxidative stress caused by neonatal hyperoxia. IL-33 receptor signaling and ILC2s were vital for the induction of asthma-like features following neonatal hyperoxia. Serum IL-33 levels correlated significantly with serum levels of IL-5 and IL-13 but not IL-4 in preterm infants. Conclusions These data demonstrate that an axis involving IL-33 and ILC2s is important for the development of asthma-like features following neonatal hyperoxia and suggest therapeutic potential for targeting IL-33, ILC2s, and oxidative stress to prevent and/or treat asthma development related to prematurity.
PD-1hi CD8+ resident memory T cells balance immunity and fibrotic sequelae
(Science Immunology, 2019-06-14) Wang, Zheng; Wang, Shaohua; Goplen, Nick P.; Li, Chaofan; Cheon, In Su; Dai, Qigang; Huang, Su; Shan, Jinjun; Ma, Chaoyu; Ye, Zhenqing; Xiang, Min; Limper, Andrew H.; Porquera, Eva-Carmona; Kohlmeier, Jacob E.; Kaplan, Mark H.; Zhang, Nu; Johnson, Aaron J.; Vassallo, Robert; Sun, Jie; Microbiology and Immunology, School of Medicine
CD8+ tissue-resident memory T (TRM) cells provide frontline immunity in mucosal tissues. The mechanisms regulating CD8+ TRM maintenance, heterogeneity, and protective and pathological functions are largely elusive. Here, we identify a population of CD8+ TRM cells that is maintained by major histocompatibility complex class I (MHC-I) signaling, and CD80 and CD86 costimulation after acute influenza infection. These TRM cells have both exhausted-like phenotypes and memory features and provide heterologous immunity against secondary infection. PD-L1 blockade after the resolution of primary infection promotes the rejuvenation of these exhausted-like TRM cells, restoring protective immunity at the cost of promoting postinfection inflammatory and fibrotic sequelae. Thus, PD-1 serves to limit the pathogenic capacity of exhausted-like TRM cells at the memory phase. Our data indicate that TRM cell exhaustion is the result of a tissue-specific cellular adaptation that balances fibrotic sequelae with protective immunity.
PPAR-γ in Macrophages Limits Pulmonary Inflammation and Promotes Host Recovery Following Respiratory Viral Infection
(American Society for Microbiology, 2019-05-01) Huang, Su; Zhu, Bibo; Cheon, In Su; Goplen, Nick P.; Jiang, Li; Zhang, Ruixuan; Peebles, R. Stokes; Mack, Matthias; Kaplan, Mark H.; Limper, Andrew H.; Sun, Jie; Pediatrics, School of Medicine
Alveolar macrophages (AM) play pivotal roles in modulating host defense, pulmonary inflammation, and tissue injury following respiratory viral infections. However, the transcriptional regulation of AM function during respiratory viral infections is still largely undefined. Here we have screened the expression of 84 transcription factors in AM in response to influenza A virus (IAV) infection. We found that the transcription factor PPAR-γ was downregulated following IAV infection in AM through type I interferon (IFN)-dependent signaling. PPAR-γ expression in AM was critical for the suppression of exaggerated antiviral and inflammatory responses of AM following IAV and respiratory syncytial virus (RSV) infections. Myeloid PPAR-γ deficiency resulted in enhanced host morbidity and increased pulmonary inflammation following both IAV and RSV infections, suggesting that macrophage PPAR-γ is vital for restricting severe host disease development. Using approaches to selectively deplete recruiting monocytes, we demonstrate that PPAR-γ expression in resident AM is likely important in regulating host disease development. Furthermore, we show that PPAR-γ was critical for the expression of wound healing genes in AM. As such, myeloid PPAR-γ deficiency resulted in impaired inflammation resolution and defective tissue repair following IAV infection. Our data suggest a critical role of PPAR-γ expression in lung macrophages in the modulation of pulmonary inflammation, the development of acute host diseases, and the proper restoration of tissue homeostasis following respiratory viral infections.IMPORTANCE Respiratory viral infections, like IAV and respiratory syncytial virus (RSV) infections, impose great challenges to public health. Alveolar macrophages (AM) are lung-resident immune cells that play important roles in protecting the host against IAV and RSV infections. However, the underlying molecular mechanisms by which AM modulate host inflammation, disease development, and tissue recovery are not very well understood. Here we identify that PPAR-γ expression in AM is crucial to suppress pulmonary inflammation and diseases and to promote fast host recovery from IAV and RSV infections. Our data suggest that targeting macrophage PPAR-γ may be a promising therapeutic option in the future to suppress acute inflammation and simultaneously promote recovery from severe diseases associated with respiratory viral infections.
Respiratory mucosal immunity against SARS-CoV-2 after mRNA vaccination
(American Association for the Advancement of Science, 2022) Tang, Jinyi; Zeng, Cong; Cox, Thomas M.; Li, Chaofan; Son, Young Min; Cheon, In Su; Wu, Yue; Behl, Supriya; Taylor, Justin J.; Chakraborty, Rana; Johnson, Aaron J.; Schiavo, Dante N.; Utz, James P.; Reisenauer, Janani S.; Midthun, David E.; Mullon, John J.; Edell, Eric S.; Alameh, Mohamad G.; Borish, Larry; Teague, William G.; Kaplan, Mark H.; Weissman, Drew; Kern, Ryan; Hu, Haitao; Vassallo, Robert; Liu, Shan-Lu; Sun, Jie; Microbiology and Immunology, School of Medicine
SARS-CoV-2 mRNA vaccination induces robust humoral and cellular immunity in the circulation; however, it is currently unknown whether it elicits effective immune responses in the respiratory tract, particularly against variants of concern (VOCs), including Omicron. We compared the SARS-CoV-2 S-specific total and neutralizing antibody responses, and B and T cell immunity, in the bronchoalveolar lavage fluid (BAL) and blood of COVID-19-vaccinated individuals and hospitalized patients. Vaccinated individuals had significantly lower levels of neutralizing antibody against D614G, Delta (B.1.617.2), and Omicron BA.1.1 in the BAL compared with COVID-19 convalescents despite robust S-specific antibody responses in the blood. Furthermore, mRNA vaccination induced circulating S-specific B and T cell immunity, but in contrast to COVID-19 convalescents, these responses were absent in the BAL of vaccinated individuals. Using a mouse immunization model, we demonstrated that systemic mRNA vaccination alone induced weak respiratory mucosal neutralizing antibody responses, especially against SARS-CoV-2 Omicron BA.1.1 in mice; however, a combination of systemic mRNA vaccination plus mucosal adenovirus-S immunization induced strong neutralizing antibody responses not only against the ancestral virus but also the Omicron BA.1.1 variant. Together, our study supports the contention that the current COVID-19 vaccines are highly effective against severe disease development, likely through recruiting circulating B and T cell responses during reinfection, but offer limited protection against breakthrough infection, especially by the Omicron sublineage. Hence, mucosal booster vaccination is needed to establish robust sterilizing immunity in the respiratory tract against SARS-CoV-2, including infection by the Omicron sublineage and future VOCs.
Targeting Peroxisome Proliferator-Activated Receptor-Gamma Decreases Host Mortality After Influenza Infection in Obese Mice
(Mary Ann Liebert, 2019-05-15) Huang, Su; Jiang, Li; Cheon, In Su; Su, Jie; Pediatrics, School of Medicine
Obesity is an independent risk factor for severe influenza infection. However, the underlying cellular and molecular mechanisms are still incompletely understood. In this study, we have utilized a murine influenza infection model in genetic-induced obese (db/db) mice to explore the mechanisms by which obesity increases host susceptibility to influenza infection. We find that db/db mice have enhanced viral replication, exaggerated inflammatory responses, and dysregulated lung repair process after influenza infection, and consequently increased host mortality. Furthermore, we demonstrate that the transcription factor peroxisome proliferator-activated receptor-gamma (PPAR-γ), an important inflammation regulator, was downregulated in the lung macrophages of db/db mice after influenza infection. Strikingly, the treatment of 15-deoxy-Δ12, 14-prostaglandin J2 (15d-PGJ2), a PPAR-γ agonist, largely rescued the survival of db/db mice after influenza infection. Interestingly, macrophage PPAR-γ-deficient mice exhibited enhanced mortality after influenza infection and 15d-PGJ2 fails to rescue host mortality in macrophage PPAR-γ-deficient mice, suggesting that PPAR-γ expression in macrophages is critical for the action of 15d-PGJ2. These data indicate that obesity attenuates lung antiviral immunity and hampers host recovery through the modulation of macrophage PPAR-γ expression. Furthermore, modalities targeting macrophage PPAR-γ expression and/or function may serve as promising therapeutics to treat severe influenza infection in obese patients.
Tissue-resident CD4+ T helper cells assist the development of protective respiratory B and CD8+ T cell memory responses
(American Association for the Advancement of Science, 2021) Son, Young Min; Cheon, In Su; Wu, Yue; Li, Chaofan; Wang, Zheng; Gao, Xiaochen; Chen, Yao; Takahashi, Yoshimasa; Fu, Yang-Xin; Dent, Alexander L.; Kaplan, Mark H.; Taylor, Justin J.; Cui, Weiguo; Sun, Jie; Microbiology and Immunology, School of Medicine
Much remains unknown about the roles of CD4+ T helper cells in shaping localized memory B cell and CD8+ T cell immunity in the mucosal tissues. Here, we report that lung T helper cells provide local assistance for the optimal development of tissue-resident memory B and CD8+ T cells after the resolution of primary influenza virus infection. We have identified a population of T cells in the lung that exhibit characteristics of both follicular T helper and TRM cells, and we have termed these cells as resident helper T (TRH) cells. Optimal TRH cell formation was dependent on transcription factors involved in T follicular helper and resident memory T cell development including BCL6 and Bhlhe40. We show that TRH cells deliver local help to CD8+ T cells through IL-21-dependent mechanisms. Our data have uncovered the presence of a tissue-resident helper T cell population in the lung that plays a critical role in promoting the development of protective B cell and CD8+ T cell responses.
Uncoupling of macrophage inflammation from self-renewal modulates host recovery from respiratory viral infection
(Cell Press, 2021) Zhu, Bibo; Wu, Yue; Huang, Su; Zhang, Ruixuan; Son, Young Min; Li, Chaofan; Cheon, In Su; Gao, Xiaochen; Wang, Min; Chen, Yao; Zhou, Xian; Nguyen, Quynh; Phan, Anthony T.; Behl, Supriya; Taketo, M. Mark; Mack, Matthias; Shapiro, Virginia S.; Zeng, Hu; Ebihara, Hideki; Mullon, John J.; Edell, Eric S.; Reisenauer, Janani S.; Demirel, Nadir; Kern, Ryan M.; Chakraborty, Rana; Cui, Weiguo; Kaplan, Mark H.; Zhou, Xiaobo; Goldrath, Ananda W.; Sun, Jie; Microbiology and Immunology, School of Medicine
Tissue macrophages self-renew during homeostasis and produce inflammatory mediators upon microbial infection. We examined the relationship between proliferative and inflammatory properties of tissue macrophages by defining the impact of the Wnt/β-catenin pathway, a central regulator of self-renewal, in alveolar macrophages (AMs). Activation of β-catenin by Wnt ligand inhibited AM proliferation and stemness, but promoted inflammatory activity. In a murine influenza viral pneumonia model, β-catenin-mediated AM inflammatory activity promoted acute host morbidity; in contrast, AM proliferation enabled repopulation of reparative AMs and tissue recovery following viral clearance. Mechanistically, Wnt treatment promoted β-catenin-HIF-1α interaction and glycolysis-dependent inflammation while suppressing mitochondrial metabolism and thereby, AM proliferation. Differential HIF-1α activities distinguished proliferative and inflammatory AMs in vivo. This β-catenin-HIF-1α axis was conserved in human AMs and enhanced HIF-1α expression associated with macrophage inflammation in COVID-19 patients. Thus, inflammatory and reparative activities of lung macrophages are regulated by β-catenin-HIF-1α signaling, with implications for the treatment of severe respiratory diseases.

Browsing by Author "Cheon, In Su"

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