Citations

Staphylococcus aureus is a well-known pathogen responsible for a wide range of diseases with life-threatening consequences. Its public health burden continues to be significant due to pervasive colonization and growing antimicrobial-resistance (i.e., methicillin-resistant S. aureus, MRSA). In the present study we found that exposure of human bronchial epithelial (hBE) cells to spent culture supernatants of the MRSA strain USA300 induced an increase in mitochondrial ROS production and ATP release that was inhibited by pretreatment with the ROS scavenger glutathione (GSH). ATP secretion involved activation of probenecid-sensitive pannexin 1 channels and bafilomycin A1-dependent exocytosis. ATP exocytosis was inhibited by an antagonist peptide targeting the Receptor for Advanced Glycation End (RAGE) products suggesting that RAGE activation was involved in regulating vesicular ATP release. ATP secretion produced a sustained increase in intracellular Ca 2+ concentration which was dependent upon Ca 2+ uptake from the extracellular solution. Moreover, the sustained JE2-induced Ca 2+ response was not observed in spent supernatants from the less virulent S. aureus agrA mutants used to stimulate hBE cells whereas media from fadX and codY mutants produced responses similar to JE2. Furthermore, wildtype, fadX and codY supernatants evoked secretion of the type-2 inflammatory cytokine IL-33, whereas no response was elicited by media from the less virulent argA mutant. These findings indicate that exposure to secreted virulence factors from S. aureus induces oxidative stress in hBE cells that leads to ATP secretion, sustained Ca 2+ uptake and IL-33 secretion, which has been previously shown to induce type-2 inflammation in airways. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Abstract Diffuse midline glioma (DMG) is a universally fatal pediatric brainstem cancer. Outside of clinical trials, palliative radiotherapy (RT) remains the only approved treatment, with a median overall survival (OS) of <12 months. The brain-penetrant oral therapy dordaviprone (ONC201) has demonstrated early clinical efficacy by activating the overexpressed mitochondrial protease ClpP, inducing mitochondrial dysfunction. Our previous studies identified that dordaviprone triggers compensatory energy production via the PI3K/mTOR pathway to avoid cell death. To overcome this adaptation, we combined dordaviprone with the brain-penetrant pan-PI3K/mTOR inhibitor paxalisib, showing synergistic anti-tumor effects across multiple immunocompromised patient-derived xenograft models. These results led to the international Phase II clinical trial (PNOC022/NCT05009992), where >20% of patients enrolled pre-radiation achieved survival beyond 2 years. However, approximately 20% of patients experienced immune-related toxicities-mucositis, colitis, and skin reactions, likely driven by paxalisib’s pan-PI3K inhibition, as PIK3CG (p110γ) and PIK3CD (p110δ) are enriched in hematopoietic cells. In contrast, PIK3CA (p110α) is a known genetic dependency in DMG. We hypothesized that the brain-penetrant, p110α-selective inhibitor GCT-007 could maintain therapeutic efficacy while reducing immune toxicity. DMG patient-derived cell lines showed comparable sensitivity to paxalisib and GCT-007 (mean IC50: 0.659 μM vs. 0.775 μM, respectively). Unbiased proteomic profiling in two DMG lines treated with GCT-007 identified robust downregulation of PI3K/AKT/mTOR signaling, confirmed via immunoblotting. Pathway enrichment further showed upregulation of oxidative phosphorylation, reinforcing the rationale for synergistic combination with dordaviprone. In aggressive immunocompetent syngeneic models, GCT-007 significantly extended overall survival (median 53 vs. 40 days, p=0.0001). When combined with dordaviprone, enzastaurin, or immune checkpoint inhibitors (ICI), GCT-007 increased survival in immune-competent DMG models by an average of 53% to 77% compared to vehicle (p=0.001), with 25% of mice in the GCT-007 + ICI cohort achieving long-term survival. Ongoing spatial profiling of the tumor immune microenvironment and organ-toxicity screening is underway to support translation.

IntroductionCervical spine defects result in spinal instability, putting the spinal cord and vertebral arteries at risk of damage and possibly devastating neurological injuries. The fibula free flap can span the spinal defects for stability. There is a paucity of literature on this technique.MethodMulti‐institutional retrospective case series reviewing patients who underwent cervical spine reconstruction with a fibula free flap. Patient demographic information, comorbidities, characteristics of cervical spine defects, and free flap complications were collected.ResultsA total of 1187 fibula free flaps across 10 different institutions were reviewed. Thirteen patients (1.09%) underwent cervical spine reconstruction with a fibula free flap. Average age was 52.3 years old with an age range of 12–79 years. There were six males (46.1%) and seven females (53.8%). The most common defect etiology was infection (n = 6, 46.1%). Most commonly involved cervical spine level of the defect was C5 (n = 10) followed by C6 (n = 9) and C4 (n = 8). The majority of reconstructed defects spanned three or more cervical levels, (n = 9, 69.2%). Facial artery was the most common arterial anastomosis (n = 8). Eight patients (61.5%) required a tracheostomy during their postoperative course. None of the patients had symptomatic or radiographic nonunion.ConclusionThis case series demonstrates that a vascularized fibula flap is a potential reconstructive option for cervical spine defects, especially in defects greater than three cervical levels, in the setting of infection, and previously radiated patients.Level of Evidence4 Laryngoscope, 134:4923–4928, 2024

Abstract H3K27M-mutant diffuse midline glioma (DMG) patients have no proven effective therapies beyond radiation. ONC201, a mitochondrial protease ClpP agonist, has recently demonstrated efficacy in these patients, but the mechanism behind this remains unknown. We assessed clinical outcomes, tumor sequencing, and tissue samples from patients treated in two completed multi-site clinical studies (n=71). Patients treated with ONC201 monotherapy following initial radiation but prior to recurrence (n=35) demonstrated a median overall survival of 21.7 months and a median progression-free survival of 12.2 months. Radiographic response was associated with increased expression of key tricarboxylic acid cycle-related genes in baseline tumor sequencing. Similar survival benefits were observed using in utero electroporation and orthotopic mouse models of H3K27M-DMG (median 107 versus 77 days [p=0.02] and median 97 versus 141 days [p=0.004], respectively). Integrated transcriptomic and metabolomic analysis of ONC201-treated H3K27M-DMG cells revealed downregulation of TCA cycle, glycolysis, and pyruvate metabolism genes, most notably oxoglutarate dehydrogenase (OGDH), and concomitant changes in levels of associated metabolites including ɑ-ketoglutarate (ɑ-KG). Interestingly, L-2-hydroxyglutarate (L-2HG), a known inhibitor of the Jumonji C domain family of histone lysine demethylases, was also increased. This corresponded with increases in repressive H3K27me3 in vitro and in human tumors accompanied by epigenetic downregulation of cell cycle regulation and neuro-glial differentiation genes. Genetic knockdown of OGDH recapitulated ONC201-mediated increases in H3K27me3. In contrast, genetic knockdown of ClpP or lactate dehydrogenase A or overexpression of L-2-hydroxyglutarate dehydrogenase (L-2HGDH), but not D-2HGDH, abrogated ONC201-mediated increases in H3K27me3, demonstrating that ONC201 induces the production of L-2HG in H3K27M-DMG cells leading to increased H3K27me3. Overall, our data demonstrates the efficacy of ONC201 in H3K27M-mutant DMG and supports ONC201 as the first monotherapy to improve outcomes in patients with H3K27M-mutant DMG for whom few therapeutic options currently exist. Mechanistically, ONC201 disrupts integrated metabolic and epigenetic pathways and reverses pathognomonic H3K27me3 reduction.

Hyponatraemia on hospital admission is associated with increased length of stay, healthcare expenditures and mortality. Urine studies collected before fluid or diuretic administration are essential to diagnose the underlying cause of hyponatraemia, thereby empowering admitting teams to employ the appropriate treatment. A multidisciplinary quality improvement (QI) team led by internal medicine residents performed a QI project from July 2020 through June 2021 to increase the rate of urine studies collected before fluid or diuretic administration in the emergency department (ED) in patients admitted with moderate to severe hyponatraemia. We implemented two plan-do-study-act (PDSA) cycles to address this goal. In PDSA Cycle #1, we displayed an educational poster in employee areas of the ED and met with nursing staff at their monthly meetings to communicate the project and answer questions. We also obtained agreement from ED attending physicians and nursing leaders to support the project. In PDSA Cycle #2, we implemented a structural change in the nursing triage process to issue every patient who qualified for bloodwork with a urine specimen container labelled with a medical record number on registration so that the patient could provide a sample at any point, including while in the waiting area. After PDSA Cycle #1, urine specimen collection increased from 34.5% to 57.5%. After PDSA Cycle #2, this increased further to 59%. We conclude that a combination of educational and structural changes led to a significant increase in urine specimen collection before fluid or diuretic administration among patients presenting with moderate-to-severe hyponatraemia in the ED.

Abstract Patients with H3K27M-mutant diffuse midline glioma (DMG) have no proven effective therapies. ONC201 has recently demonstrated efficacy in these patients, but the mechanism behind this finding remains unknown. We assessed clinical outcomes, tumor sequencing, and tissue/cerebrospinal fluid (CSF) correlate samples from patients treated in two completed multisite clinical studies. Patients treated with ONC201 following initial radiation but prior to recurrence demonstrated a median overall survival of 21.7 months, whereas those treated after recurrence had a median overall survival of 9.3 months. Radiographic response was associated with increased expression of key tricarboxylic acid cycle–related genes in baseline tumor sequencing. ONC201 treatment increased 2-hydroxyglutarate levels in cultured H3K27M-DMG cells and patient CSF samples. This corresponded with increases in repressive H3K27me3 in vitro and in human tumors accompanied by epigenetic downregulation of cell cycle regulation and neuroglial differentiation genes. Overall, ONC201 demonstrates efficacy in H3K27M-DMG by disrupting integrated metabolic and epigenetic pathways and reversing pathognomonic H3K27me3 reduction. Significance: The clinical, radiographic, and molecular analyses included in this study demonstrate the efficacy of ONC201 in H3K27M-mutant DMG and support ONC201 as the first monotherapy to improve outcomes in H3K27M-mutant DMG beyond radiation. Mechanistically, ONC201 disrupts integrated metabolic and epigenetic pathways and reverses pathognomonic H3K27me3 reduction. This article is featured in Selected Articles from This Issue, p. 2293