Impaired oxidative phosphorylation regulates necroptosis in human lung epithelial cells.

Cellular metabolism can impact cell life or death outcomes. While metabolic dysfunction has been linked to cell death, the mechanisms by which metabolic dysfunction regulates the cell death mode called necroptosis remain unclear. Our study demonstrates that mitochondrial oxidative phosphorylation (OXPHOS) activates programmed necrotic cell death (necroptosis) in human lung epithelial cells. Inhibition of mitochondrial respiration and ATP synthesis induced the phosphorylation of mixed lineage kinase domain-like protein (MLKL) and necroptotic cell death. Furthermore, we demonstrate that the activation of AMP-activated protein kinase (AMPK), resulting from impaired mitochondrial OXPHOS, regulates necroptotic cell death. These results suggest that impaired mitochondrial OXPHOS contributes to necroptosis in human lung epithelial cells.

Recurrence after postoperative intravesical instillation therapy in Hunner type interstitial cystitis.

We performed a prospective, single-arm study comparing outcomes between transurethral ablation plus postoperative instillation of hyaluronic acid and chondroitin sulfate (HACS group) and transurethral ablation only in patients with Hunner type interstitial cystitis (historical control group). A total of 78 patients were enrolled, and 51 were included in the per-protocol analysis set. The 2-year recurrence rate was 47.1% (95% CI, 32.9-61.5) in the HACS group, which was significantly lower than that in the control group (86.2%; 95% CI, 74.6-93.9, P < 0.001). After instillation therapy, the hazard ratio for recurrence was 0.38 (95% CI, 0.23-0.65, P < 0.001). The HACS group had an increased recurrence-free survival with the median interval not being reached, while it was 11.4 months in the control group (95% CI, 8.8-13.8, P < 0.001). Regardless of the instillation treatment, there were significant improvements in all symptom questionnaire scores and pain compared to the baseline. However, in the instillation group, improvement was stable even after 12 months. In patients with Hunner type interstitial cystitis, intravesical instillation of hyaluronic acid and chondroitin sulfate after transurethral ablation significantly reduced the recurrence rate and maintained symptom improvement for more than 1 year.

Utility of Contemporary Health Screening in the Diagnosis of Bladder Cancer.

BACKGROUND: To evaluate the utility of contemporary health screening (HS) in the diagnosis of bladder cancer (BCa). METHODS: We retrospectively reviewed 279,683 individuals who underwent HS between February 1995 and April 2015. Among these individuals, 74 were diagnosed with BCa within a year after the HS and were included in the analysis. Screen-detected BCa was defined as when a referral was made to a urologist due to microscopic hematuria (MH) on urinalysis, abnormal imaging, or any urological symptoms observed at the HS. Screen-undetected BCa was defined as when no referral was made to a urologist because of no abnormality observed at the HS, but a visit to a urological outpatient clinic later was followed by a BCa diagnosis. The incidences of screen-detected BCa and BCa in the Korean population were compared. Clinicopathological characteristics were compared between the screen-detected BCa and screen-undetected BCa groups. RESULTS: The detection rate of BCa was 17.2 per 100,000, which exceeded the 2020 estimated national crude incidence rate of 9.3 per 100,000 by approximately 1.7 times. Among the 74 patients diagnosed with BCa within a year after HS, 48 (64.9%) had screen-detected BCa. The screen-detected BCa group had a higher T stage (p = 0.009) and grade (p = 0.019) than the screen-undetected BCa group. However, the overall survival was not significantly different between the two groups (p = 0.677). A positive correlation between the MH grade and the T stage was identified (p = 0.001). CONCLUSION: Although HS is not focused on BCa screening, contemporary HS can contribute to the detection of BCa.

NOX4-dependent fatty acid oxidation promotes NLRP3 inflammasome activation in macrophages.

Altered metabolism has been implicated in the pathogenesis of inflammatory diseases. NADPH oxidase 4 (NOX4), a source of cellular superoxide anions, has multiple biological functions that may be of importance in inflammation and in the pathogenesis of human metabolic diseases, including diabetes. However, the mechanisms by which NOX4-dependent metabolic regulation affect the innate immune response remain unclear. Here we show that deficiency of NOX4 resulted in reduced expression of carnitine palmitoyltransferase 1A (CPT1A), which is a key mitochondrial enzyme in the fatty acid oxidation (FAO) pathway. The reduced FAO resulted in less activation of the nucleotide-binding domain, leucine-rich-repeat-containing receptor (NLR), pyrin-domain-containing 3 (NLRP3) inflammasome in human and mouse macrophages. In contrast, NOX4 deficiency did not inhibit the activation of the NLR family, CARD-domain-containing 4 (NLRC4), the NLRP1 or the absent in melanoma 2 (AIM2) inflammasomes. We also found that inhibition of FAO by etomoxir treatment suppressed NLRP3 inflammasome activation. Furthermore, Nox4-deficient mice showed substantial reduction in caspase-1 activation and in interleukin (IL)-1ß and IL-18 production, and there was improved survival in a mouse model of NLRP3-mediated Streptococcus pneumoniae infection. The pharmacologic inhibition of NOX4 by either GKT137831, which is currently in phase 2 clinical trials, or VAS-2870 attenuated NLRP3 inflammasome activation. Our results suggest that NOX4-mediated FAO promotes NLRP3 inflammasome activation.