Macrophages undergo a metabolic switch from oxidative phosphorylation to glycolysis when exposed to gram-negative bacterial lipopolysaccharide (LPS), which modulates antibacterial host defence mechanisms. Here, we show that LPS treatment of macrophages increased the classical oxidative burst response via the NADPH oxidase (NOX) 2 enzyme, which was blocked by 2-deoxyglucose (2-DG) inhibition of glycolysis. The inhibition of the pentose phosphate pathway with 6-aminonicotinamide (6-AN) also suppressed the LPS-induced increase in NOX2 activity and was associated with a significant reduction in the mRNA expression of NOX2 and its organizer protein p47phox. Notably, the LPS-dependent enhancement in NOX2 oxidase activity was independent of both succinate and mitochondrial reactive oxygen species (ROS) production. LPS also increased type I IFN-β expression, which was suppressed by 2-DG and 6-AN and, therefore, is dependent on glycolysis and the pentose phosphate pathway. The type I IFN-β response to LPS was also inhibited by apocynin pre-treatment, suggesting that NOX2-derived ROS promotes the TLR4-induced response to LPS. Moreover, recombinant IFN-β increased NOX2 oxidase-dependent ROS production, as well as NOX2 and p47phox expression. Our findings identify a previously undescribed molecular mechanism where both glycolysis and the pentose phosphate pathway are required to promote LPS-induced inflammation in macrophages.

Prostate cancer is ranked second in the world for cancer-related deaths in men, highlighting the lack of effective therapies for advanced-stage disease. Toll-like receptors (TLRs) and immunity have a direct role in prostate cancer pathogenesis, but TLR9 has been reported to contribute to both the progression and inhibition of prostate tumorigenesis. To further understand this apparent disparity, we have investigated the effect of TLR9 stimulation on prostate cancer progression in an immune-competent, syngeneic orthotopic mouse model of prostate cancer. Here, we utilized the class B synthetic agonist CPG-1668 to provoke a TLR9-mediated systemic immune response and demonstrate a significant impairment of prostate tumorigenesis. Untreated tumors contained a high abundance of immune-cell infiltrates. However, pharmacological activation of TLR9 resulted in smaller tumors containing significantly fewer M1 macrophages and T cells. TLR9 stimulation of tumor cells in vitro had no effect on cell viability or its downstream transcriptional targets, whereas stimulation in macrophages suppressed cancer cell growth via type I IFN. This suggests that the antitumorigenic effects of CPG-1668 were predominantly mediated by an antitumor immune response. This study demonstrated that systemic TLR9 stimulation negatively regulates prostate cancer tumorigenesis and highlights TLR9 agonists as a useful therapeutic for the treatment of prostate cancer.

Coccidioides species are thermally dimorphic fungal pathogens that cause coccidioidomycosis (Valley Fever) primarily in North and South America. Coccidioides grow as hyphae that differentiate into arthroconidia, which can be aerosolized upon soil disturbance, and inhaled by the mammalian host to cause pulmonary infections with occasional dissemination to other organs. In the context of mouse models, current methods of infection include intranasal, intravenous, and intraperitoneal delivery of the arthroconidia into mice. To explore an aerosol route of infection, we compared the intranasal method with aerosolization using the Glass-Col Inhalation Exposure System (IES). Infection with a dose of 2 × 10⁶ CFU/mL, nebulized in 5 mL of PBS, but not in water, was able to infect mice, albeit inconsistently, compared to intranasal challenge. Arthroconidia were detected inside the IES after the nebulization and decontamination cycles. These studies highlight some of the challenges with aerosolization of Coccidioides arthroconidia and serve as a reminder about biosafety considerations for use of the IES to aerosolize pathogens.

The Nod-like receptor family pyrin domain–containing 3 (NLRP3) inflammasome is a cytosolic multiprotein immune sensor that is restrained from assembling at steady state. Mutations in NLRP3 associated with cryopyrin-associated periodic syndrome (CAPS) enhance inflammasome formation and activation, resulting in neutrophil-predominant systemic and tissue inflammation. Here, we investigated how gasdermin D (GSDMD) and GSDME drive interleukin-1β (IL-1β) release, pyroptosis, and autoinflammation during constitutive and canonical NLRP3 activation in neutrophils. Mass cytometry analysis of neutrophils from patients with CAPS revealed heterogeneous subtypes with differing amounts of intracellular IL-1β. In mice, neutrophil-specific expression of activating Nlrp3 mutations orthologous to those in patients with CAPS uncovered nonredundant roles for GSDMD and GSDME downstream of inflammasome activation. Combined deletion of Gsdmd and Gsdme in these CAPS models reduced IL-1β secretion, prevented pyroptosis, and mitigated autoinflammation. Loss of both GSDMD and GSDME reduced caspase-1 cleavage and pro–IL-1β processing downstream of NLRP3 activation, whereas GSDMD deficiency alone increased cleavage of GSDME and caspase-8. Clusters of GSDMD and GSDME were closely associated with one another at the plasma membrane of activated neutrophils from CAPS mice. These findings indicate that the coordinated actions of membrane-associated GSDMD and GSDME reinforce cytosolic NLRP3 inflammasome activation to promote IL-1β secretion, lytic cell death, and autoinflammation.

Coccidioides is a dimorphic fungal pathogen that grows as a mold in soil and produces infectious arthroconidia. Inhaled arthroconidia transition to spherules containing endospores in mammalian hosts. How distinct developmental forms of Coccidioides interact with immune cells remains poorly defined. Here, we show that arthroconidia activates TLR2 and induces NLRP3-pyrin inflammasomes in macrophages, while ferroptotic signaling promotes arthroconidia killing. Upon transition to spherules, only ruptured spherules—not intact ones—trigger IL-1β production through NLRP3-pyrin inflammasomes and GSDMD-GSDME pores. A TLR2-NLRP3-pyrin-IL-18 axis in macrophages promotes spherule growth. Endospores activate NLRP3 but not pyrin inflammasomes. Caspase-1-deficient mice show improved disease tolerance to coccidioidomycosis despite equivalent fungal burdens, correlating with enhanced neutrophil extracellular trap formation in lung granulomas. Neutrophils respond to spherules through NLRP3-pyrin inflammasomes, GSDMD-GSDME, and MLKL. Together, these findings reveal that Coccidioides morphotypes elicit distinct yet overlapping immune programs, coordinating inflammasome activation and regulated cell death to shape host-pathogen dynamics.