Interferon regulatory factor 1 (IRF1) regulates diverse biological functions, including modulation of cellular responses involved in tumorigenesis. Genetic mutations and altered IRF1 function are associated with several cancers. Although the function of IRF1 in the immunobiology of cancer is emerging, IRF1-specific mechanisms regulating tumorigenesis and tissue homeostasis in vivo are not clear. Here, we found that mice lacking IRF1 were hypersusceptible to colorectal tumorigenesis. IRF1 functions in both the myeloid and epithelial compartments to confer protection against AOM/DSS-induced colorectal tumorigenesis. We further found that IRF1 also prevents tumorigenesis in a spontaneous mouse model of colorectal cancer. The attenuated cell death in the colons of Irf1–/– mice was due to defective pyroptosis, apoptosis, and necroptosis (PANoptosis). IRF1 does not regulate inflammation and the inflammasome in the colon. Overall, our study identified IRF1 as an upstream regulator of PANoptosis to induce cell death during colitis-associated tumorigenesis.
Rajendra Karki, Bhesh Raj Sharma, Ein Lee, Balaji Banoth, R.K. Subbarao Malireddi, Parimal Samir, Shraddha Tuladhar, Harisankeerth Mummareddy, Amanda R. Burton, Peter Vogel, Thirumala-Devi Kanneganti
With the effectiveness of antimicrobials declining as antimicrobial resistance continues to threaten public health, we must look to alternative strategies for the treatment of infections. In this study, we investigated an innovative, drug-free, dual-wavelength irradiation approach that combines 2 wavelengths of light, 460 nm and 405 nm, against methicillin-resistant Staphylococcus aureus (MRSA). MRSA was initially irradiated with 460-nm light (90–360 J/cm2) and subsequently irradiated with aliquots of 405-nm light (54–324 J/cm2). For in vivo studies, mouse skin was abraded and infected with approximately 107 CFUs of MRSA and incubated for 3 hours before irradiating with 460 nm (360 J/cm2) and 405 nm (342 J/cm2). Naive mouse skin was also irradiated to investigate apoptosis. We found that staphyloxanthin, the carotenoid pigment in MRSA cells, promoted resistance to the antimicrobial effects of 405-nm light. In addition, we found that the photolytic effect of 460-nm light on staphyloxanthin attenuated resistance of MRSA to 405-nm light killing. Irradiation of 460 nm alone did not elicit any antimicrobial effect on MRSA. In a proof-of-principle mouse skin abrasion infection model, we observed significant killing of MRSA using the dual-wavelength irradiation approach. However, when either wavelength of light was administered alone, no significant decrease in bacterial viability was observed. Moreover, exposure of the dual-wavelength irradiation to naive mouse skin did not result in any visible apoptosis. In conclusion, a dual-wavelength irradiation strategy may offer an innovative, effective, and safe approach for the treatment of skin infections caused by MRSA.
Leon G. Leanse, Xueping Sharon Goh, Ji-Xin Cheng, David C. Hooper, Tianhong Dai
Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy. In the present study, when human induced pluripotent stem cells (hiPSCs) were differentiated into myoblasts, the myoblasts derived from DMD patient hiPSCs (DMD hiPSC–derived myoblasts) exhibited an identifiable DMD-relevant phenotype: myogenic fusion deficiency. Based on this model, we developed a DMD hiPSC–derived myoblast screening platform employing a high-content imaging (BD Pathway 855) approach to generate parameters describing morphological as well as myogenic marker protein expression. Following treatment of the cells with 1524 compounds from the Johns Hopkins Clinical Compound Library, compounds that enhanced myogenic fusion of DMD hiPSC–derived myoblasts were identified. The final hits were ginsenoside Rd and fenofibrate. Transcriptional profiling revealed that ginsenoside Rd is functionally related to FLT3 signaling, while fenofibrate is linked to TGF-β signaling. Preclinical tests in mdx mice showed that treatment with these 2 hit compounds can significantly ameliorate some of the skeletal muscle phenotypes caused by dystrophin deficiency, supporting their therapeutic potential. Further study revealed that fenofibrate could inhibit mitochondrion-induced apoptosis in DMD hiPSC–derived cardiomyocytes. We have developed a platform based on DMD hiPSC–derived myoblasts for drug screening and identified 2 promising small molecules with in vivo efficacy.
Congshan Sun, In Young Choi, Yazmin I. Rovira Gonzalez, Peter Andersen, C. Conover Talbot Jr., Shama R. Iyer, Richard M. Lovering, Kathryn R. Wagner, Gabsang Lee
HIV infection is associated with an increase in the proportion of activated CD8+ memory T cells (Tmem) that express CX3CR1, but how these cells are generated and maintained in vivo is unclear. We demonstrate that increased CX3CR1 expression on CD8+ Tmem in people living with HIV (PLWH) is dependent on coinfection with human CMV, and CX3CR1+CD8+ Tmem are enriched for a putatively immunosenescent CD57+CD28– phenotype. The cytokine IL-15 promotes the phenotype, survival, and proliferation of CX3CR1+CD57+CD8+ Tmem in vitro, whereas T cell receptor stimulation leads to their death. IL-15–driven survival is dependent on STAT5 and Bcl-2 activity, and IL-15–induced proliferation requires STAT5 and mTORC1. Thus, we identify mechanistic pathways that could explain how “inflammescent” CX3CR1+CD57+ CD8+ Tmem dominate the overall memory T cell pool in CMV-seropositive PLWH and that support reevaluation of immune senescence as a nonproliferative dead end.
Stephen R. Morris, Bonnie Chen, Joseph C. Mudd, Soumya Panigrahi, Carey L. Shive, Scott F. Sieg, Cheryl M. Cameron, David A. Zidar, Nicholas T. Funderburg, Souheil-Antoine Younes, Benigno Rodriguez, Sara Gianella, Michael M. Lederman, Michael L. Freeman
Insulin receptor signaling is crucial for white adipose tissue (WAT) function. Consequently, lack of insulin receptor (IR) in WAT results in a diabetes-like phenotype. Yet, causes for IR downregulation in WAT of patients with diabetes are not well understood. By using multiple mouse models of obesity and insulin resistance, we identify a common downregulation of IR with a reduction of mRNA expression of selenoproteins Txnrd3, Sephs2, and Gpx3 in gonadal adipose tissue. Consistently, GPX3 is also decreased in adipose tissue of insulin-resistant and obese patients. Inducing Gpx3 expression via selenite treatment enhances IR expression via activation of the transcription factor Sp1 in 3T3-L1 preadipocytes and improves adipocyte differentiation and function. Feeding mice a selenium-enriched high-fat diet alleviates diet-induced insulin resistance with increased insulin sensitivity, decreased tissue inflammation, and elevated IR expression in WAT. Again, IR expression correlated positively with Gpx3 expression, a phenotype that is also conserved in humans. Consequently, decreasing GPx3 using siRNA technique reduced IR expression and insulin sensitivity in 3T3-L1 preadipocytes. Overall, our data identify GPx3 as a potentially novel regulator of IR expression and insulin sensitivity in adipose tissue.
Robert Hauffe, Vanessa Stein, Chantal Chudoba, Tanina Flore, Michaela Rath, Katrin Ritter, Mareike Schell, Kristina Wardelmann, Stefanie Deubel, Johannes Florian Kopp, Maria Schwarz, Kai Kappert, Matthias Blüher, Tanja Schwerdtle, Anna P. Kipp, André Kleinridders
Tumor-associated macrophages (TAMs) contribute to the maintenance of a strong immunosuppressive environment, supporting tumor progression and resistance to treatment. To date, the mechanisms that drive acquisition of these immunosuppressive features are still poorly defined. Heme oxygenase-1 (HO-1) is the rate-limiting enzyme that catabolizes free heme. It displays important cytoprotective, antiinflammatory, and antioxidant properties. A growing body of evidence suggests that HO-1 may also promote tumor development. Herein, we show that HO-1 is highly expressed in monocytic cells in the tumor microenvironment (TME) once they differentiate into TAMs. Deletion of HO-1 in the myeloid compartment enhances the beneficial effects of a therapeutic antitumor vaccine by restoring CD8+ T cell proliferation and cytotoxicity. We further show that induction of HO-1 plays a major role in monocyte education by tumor cells by modulating their transcriptional and epigenetic programs. These results identify HO-1 as a valuable therapeutic target to reprogram the TME and synergize with current cancer therapies to facilitate antitumor response.
Emmanuelle Alaluf, Benoît Vokaer, Aurélie Detavernier, Abdulkader Azouz, Marion Splittgerber, Alice Carrette, Louis Boon, Frédérick Libert, Miguel Soares, Alain Le Moine, Stanislas Goriely
Protease-activated receptor 2 (PAR2) has long been implicated in inflammatory and visceral pain, but the cellular basis of PAR2-evoked pain has not been delineated. Although PAR2-evoked pain has been attributed to sensory neuron expression, RNA-sequencing experiments show ambiguous F2rl1 mRNA detection. Moreover, many pharmacological tools for PAR2 are nonspecific, acting also on the Mas-related GPCR family (Mrg) that are highly enriched in sensory neurons. We sought to clarify the cellular basis of PAR2-evoked pain. We developed a PAR2–conditional knockout mouse and specifically deleted PAR2 in all sensory neurons using the PirtCre mouse line. Our behavioral findings show that PAR2 agonist–evoked mechanical hyperalgesia and facial grimacing, but not thermal hyperalgesia, are dependent on PAR2 expression in sensory neurons that project to the hind paw in male and female mice. F2rl1 mRNA is expressed in a discrete population (~4%) of mostly small-diameter sensory neurons that coexpress the Nppb and IL31ra genes. This cell population has been implicated in itch, but our work shows that PAR2 activation in these cells causes clear pain-related behaviors from the skin. Our findings show that a discrete population of DRG sensory neurons mediate PAR2-evoked pain.
Shayne N. Hassler, Moeno Kume, Juliet M. Mwirigi, Ayesha Ahmad, Stephanie Shiers, Andi Wangzhou, Pradipta R. Ray, Serge N. Belugin, Dhananjay K. Naik, Michael D. Burton, Josef Vagner, Scott Boitano, Armen N. Akopian, Gregory Dussor, Theodore J. Price
Alveolar macrophages (AM) play a central role in initiation and resolution of lung inflammation, but the integration of these opposing core functions is poorly understood. AM expression of cholesterol 25-hydroxylase (CH25H), the primary biosynthetic enzyme for 25-hydroxycholesterol (25HC), far exceeds the expression of macrophages in other tissues, but no role for CH25H has been defined in lung biology. As 25HC is an agonist for the antiinflammatory nuclear receptor, liver X receptor (LXR), we speculated that CH25H might regulate inflammatory homeostasis in the lung. Here, we show that, of natural oxysterols or sterols, 25HC is induced in the inflamed lung of mice and humans. Ch25h–/– mice fail to induce 25HC and LXR target genes in the lung after LPS inhalation and exhibit delayed resolution of airway neutrophilia, which can be rescued by systemic treatment with either 25HC or synthetic LXR agonists. LXR-null mice also display delayed resolution, suggesting that native oxysterols promote resolution. During resolution, Ch25h is induced in macrophages upon their encounter with apoptotic cells and is required for LXR-dependent prevention of AM lipid overload, induction of Mertk, efferocytic resolution of airway neutrophilia, and induction of TGF-β. CH25H/25HC/LXR is, thus, an inducible metabolic axis that programs AMs for efferocytic resolution of inflammation.
Jennifer H. Madenspacher, Eric D. Morrell, Kymberly M. Gowdy, Jeffrey G. McDonald, Bonne M. Thompson, Ginger Muse, Jennifer Martinez, Seddon Thomas, Carmen Mikacenic, Jerry A. Nick, Edward Abraham, Stavros Garantziotis, Renee D. Stapleton, Julie M. Meacham, Mary Jane Thomassen, William J. Janssen, Donald N. Cook, Mark M. Wurfel, Michael B. Fessler
Eighty-six infants born without a thymus have been treated with allogeneic cultured thymus tissue implantation (CTTI). These infants, who lack T cells and are profoundly immunodeficient at birth, after CTTI from an unmatched donor develop T cells similar to those of recipient that are tolerant to both their own major histocompatibility antigens and those of the donor. We tested use of CTTI with the goal of inducing tolerance to unmatched heart transplants in immunocompetent rats. We thymectomized and T cell–depleted Lewis rats. The rats were then given cultured thymus tissue from F1 (Lewis × Dark Agouti ) under the kidney capsule and vascularized Dark Agouti (DA) heart transplants in the abdomen. Cyclosporine was administered for 4 months. The control group did not receive CTTI. Recipients with CTTI showed repopulation of naive and recent thymic emigrant CD4 T cells; controls had none. Recipients of CTTI did not reject DA cardiac allografts. Control animals did not reject DA grafts, due to lack of functional T cells. To confirm donor-specific unresponsiveness, MHC-mismatched Brown Norway (BN) hearts were transplanted 6 months after the initial DA heart transplant. LW rats with LWxDA CTTI rejected the third-party BN hearts (mean survival time 10 days); controls did not. CTTI recipients produced antibody against third-party BN donor but not against the DA thymus donor, demonstrating humoral donor-specific tolerance. Taken together, F1(LWxDA) CTTI given to Lewis rats resulted in specific tolerance to the allogeneic DA MHC expressed in the donor thymus, with resulting long-term survival of DA heart transplants after withdrawal of all immunosuppression.
Jean Kwun, Jie Li, Clay Rouse, Jae Berm Park, Alton B. Farris, Maragatha Kuchibhatla, Joseph W. Turek, Stuart J. Knechtle, Allan D. Kirk, M. Louise Markert
Extramedullary hematopoietic cells are present in the liver of normal neonates in the first few days of life and persist in infants with biliary atresia. Based on a previous report that liver genes are enriched by erythroid pathways, we examined the liver gene expression pattern at diagnosis and found the top 5 enriched pathways are related to erythrocyte pathobiology in children who survived with the native liver beyond 2 years of age. Using immunostaining, anti-CD71 antibodies identified CD71+ erythroid cells among extramedullary hematopoietic cells in the livers at the time of diagnosis. In mechanistic experiments, the preemptive antibody depletion of hepatic CD71+ erythroid cells in neonatal mice rendered them resistant to rhesus rotavirus–induced (RRV-induced) biliary atresia. The depletion of CD71+ erythroid cells increased the number of effector lymphocytes and delayed the RRV infection of livers and extrahepatic bile ducts. In coculture experiments, CD71+ erythroid cells suppressed the activation of hepatic mononuclear cells. These data uncover an immunoregulatory role for CD71+ erythroid cells in the neonatal liver.
Li Yang, Pranavkumar Shivakumar, Jeremy Kinder, Sing Sing Way, Bryan Donnelly, Reena Mourya, Zhenhua Luo, Jorge A. Bezerra
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